core.c 249.0 KB
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/*
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 * Performance events core code:
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 *
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 *  Copyright (C) 2008 Thomas Gleixner <tglx@linutronix.de>
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 *  Copyright (C) 2008-2011 Red Hat, Inc., Ingo Molnar
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 *  Copyright (C) 2008-2011 Red Hat, Inc., Peter Zijlstra
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 *  Copyright  ©  2009 Paul Mackerras, IBM Corp. <paulus@au1.ibm.com>
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 *
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 * For licensing details see kernel-base/COPYING
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 */

#include <linux/fs.h>
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#include <linux/mm.h>
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#include <linux/cpu.h>
#include <linux/smp.h>
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#include <linux/idr.h>
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#include <linux/file.h>
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#include <linux/poll.h>
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#include <linux/slab.h>
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#include <linux/hash.h>
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#include <linux/tick.h>
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#include <linux/sysfs.h>
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#include <linux/dcache.h>
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#include <linux/percpu.h>
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#include <linux/ptrace.h>
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#include <linux/reboot.h>
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#include <linux/vmstat.h>
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#include <linux/device.h>
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#include <linux/export.h>
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#include <linux/vmalloc.h>
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#include <linux/hardirq.h>
#include <linux/rculist.h>
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#include <linux/uaccess.h>
#include <linux/syscalls.h>
#include <linux/anon_inodes.h>
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#include <linux/kernel_stat.h>
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#include <linux/cgroup.h>
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#include <linux/perf_event.h>
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#include <linux/trace_events.h>
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#include <linux/hw_breakpoint.h>
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#include <linux/mm_types.h>
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#include <linux/module.h>
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#include <linux/mman.h>
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#include <linux/compat.h>
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#include <linux/bpf.h>
#include <linux/filter.h>
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#include <linux/namei.h>
#include <linux/parser.h>
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#include "internal.h"

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#include <asm/irq_regs.h>

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typedef int (*remote_function_f)(void *);

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struct remote_function_call {
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	struct task_struct	*p;
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	remote_function_f	func;
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	void			*info;
	int			ret;
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};

static void remote_function(void *data)
{
	struct remote_function_call *tfc = data;
	struct task_struct *p = tfc->p;

	if (p) {
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		/* -EAGAIN */
		if (task_cpu(p) != smp_processor_id())
			return;

		/*
		 * Now that we're on right CPU with IRQs disabled, we can test
		 * if we hit the right task without races.
		 */

		tfc->ret = -ESRCH; /* No such (running) process */
		if (p != current)
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			return;
	}

	tfc->ret = tfc->func(tfc->info);
}

/**
 * task_function_call - call a function on the cpu on which a task runs
 * @p:		the task to evaluate
 * @func:	the function to be called
 * @info:	the function call argument
 *
 * Calls the function @func when the task is currently running. This might
 * be on the current CPU, which just calls the function directly
 *
 * returns: @func return value, or
 *	    -ESRCH  - when the process isn't running
 *	    -EAGAIN - when the process moved away
 */
static int
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task_function_call(struct task_struct *p, remote_function_f func, void *info)
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{
	struct remote_function_call data = {
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		.p	= p,
		.func	= func,
		.info	= info,
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		.ret	= -EAGAIN,
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	};
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	int ret;
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	do {
		ret = smp_call_function_single(task_cpu(p), remote_function, &data, 1);
		if (!ret)
			ret = data.ret;
	} while (ret == -EAGAIN);
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	return ret;
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}

/**
 * cpu_function_call - call a function on the cpu
 * @func:	the function to be called
 * @info:	the function call argument
 *
 * Calls the function @func on the remote cpu.
 *
 * returns: @func return value or -ENXIO when the cpu is offline
 */
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static int cpu_function_call(int cpu, remote_function_f func, void *info)
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{
	struct remote_function_call data = {
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		.p	= NULL,
		.func	= func,
		.info	= info,
		.ret	= -ENXIO, /* No such CPU */
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	};

	smp_call_function_single(cpu, remote_function, &data, 1);

	return data.ret;
}

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static inline struct perf_cpu_context *
__get_cpu_context(struct perf_event_context *ctx)
{
	return this_cpu_ptr(ctx->pmu->pmu_cpu_context);
}

static void perf_ctx_lock(struct perf_cpu_context *cpuctx,
			  struct perf_event_context *ctx)
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{
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	raw_spin_lock(&cpuctx->ctx.lock);
	if (ctx)
		raw_spin_lock(&ctx->lock);
}

static void perf_ctx_unlock(struct perf_cpu_context *cpuctx,
			    struct perf_event_context *ctx)
{
	if (ctx)
		raw_spin_unlock(&ctx->lock);
	raw_spin_unlock(&cpuctx->ctx.lock);
}

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#define TASK_TOMBSTONE ((void *)-1L)

static bool is_kernel_event(struct perf_event *event)
{
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	return READ_ONCE(event->owner) == TASK_TOMBSTONE;
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}

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/*
 * On task ctx scheduling...
 *
 * When !ctx->nr_events a task context will not be scheduled. This means
 * we can disable the scheduler hooks (for performance) without leaving
 * pending task ctx state.
 *
 * This however results in two special cases:
 *
 *  - removing the last event from a task ctx; this is relatively straight
 *    forward and is done in __perf_remove_from_context.
 *
 *  - adding the first event to a task ctx; this is tricky because we cannot
 *    rely on ctx->is_active and therefore cannot use event_function_call().
 *    See perf_install_in_context().
 *
 * If ctx->nr_events, then ctx->is_active and cpuctx->task_ctx are set.
 */

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typedef void (*event_f)(struct perf_event *, struct perf_cpu_context *,
			struct perf_event_context *, void *);

struct event_function_struct {
	struct perf_event *event;
	event_f func;
	void *data;
};

static int event_function(void *info)
{
	struct event_function_struct *efs = info;
	struct perf_event *event = efs->event;
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	struct perf_event_context *ctx = event->ctx;
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	struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
	struct perf_event_context *task_ctx = cpuctx->task_ctx;
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	int ret = 0;
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	WARN_ON_ONCE(!irqs_disabled());

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	perf_ctx_lock(cpuctx, task_ctx);
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	/*
	 * Since we do the IPI call without holding ctx->lock things can have
	 * changed, double check we hit the task we set out to hit.
	 */
	if (ctx->task) {
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		if (ctx->task != current) {
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			ret = -ESRCH;
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			goto unlock;
		}
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		/*
		 * We only use event_function_call() on established contexts,
		 * and event_function() is only ever called when active (or
		 * rather, we'll have bailed in task_function_call() or the
		 * above ctx->task != current test), therefore we must have
		 * ctx->is_active here.
		 */
		WARN_ON_ONCE(!ctx->is_active);
		/*
		 * And since we have ctx->is_active, cpuctx->task_ctx must
		 * match.
		 */
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		WARN_ON_ONCE(task_ctx != ctx);
	} else {
		WARN_ON_ONCE(&cpuctx->ctx != ctx);
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	}
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	efs->func(event, cpuctx, ctx, efs->data);
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unlock:
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	perf_ctx_unlock(cpuctx, task_ctx);

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	return ret;
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}

static void event_function_call(struct perf_event *event, event_f func, void *data)
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{
	struct perf_event_context *ctx = event->ctx;
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	struct task_struct *task = READ_ONCE(ctx->task); /* verified in event_function */
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	struct event_function_struct efs = {
		.event = event,
		.func = func,
		.data = data,
	};
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	if (!event->parent) {
		/*
		 * If this is a !child event, we must hold ctx::mutex to
		 * stabilize the the event->ctx relation. See
		 * perf_event_ctx_lock().
		 */
		lockdep_assert_held(&ctx->mutex);
	}
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	if (!task) {
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		cpu_function_call(event->cpu, event_function, &efs);
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		return;
	}

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	if (task == TASK_TOMBSTONE)
		return;

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again:
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	if (!task_function_call(task, event_function, &efs))
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		return;

	raw_spin_lock_irq(&ctx->lock);
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	/*
	 * Reload the task pointer, it might have been changed by
	 * a concurrent perf_event_context_sched_out().
	 */
	task = ctx->task;
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	if (task == TASK_TOMBSTONE) {
		raw_spin_unlock_irq(&ctx->lock);
		return;
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	}
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	if (ctx->is_active) {
		raw_spin_unlock_irq(&ctx->lock);
		goto again;
	}
	func(event, NULL, ctx, data);
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	raw_spin_unlock_irq(&ctx->lock);
}

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/*
 * Similar to event_function_call() + event_function(), but hard assumes IRQs
 * are already disabled and we're on the right CPU.
 */
static void event_function_local(struct perf_event *event, event_f func, void *data)
{
	struct perf_event_context *ctx = event->ctx;
	struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
	struct task_struct *task = READ_ONCE(ctx->task);
	struct perf_event_context *task_ctx = NULL;

	WARN_ON_ONCE(!irqs_disabled());

	if (task) {
		if (task == TASK_TOMBSTONE)
			return;

		task_ctx = ctx;
	}

	perf_ctx_lock(cpuctx, task_ctx);

	task = ctx->task;
	if (task == TASK_TOMBSTONE)
		goto unlock;

	if (task) {
		/*
		 * We must be either inactive or active and the right task,
		 * otherwise we're screwed, since we cannot IPI to somewhere
		 * else.
		 */
		if (ctx->is_active) {
			if (WARN_ON_ONCE(task != current))
				goto unlock;

			if (WARN_ON_ONCE(cpuctx->task_ctx != ctx))
				goto unlock;
		}
	} else {
		WARN_ON_ONCE(&cpuctx->ctx != ctx);
	}

	func(event, cpuctx, ctx, data);
unlock:
	perf_ctx_unlock(cpuctx, task_ctx);
}

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#define PERF_FLAG_ALL (PERF_FLAG_FD_NO_GROUP |\
		       PERF_FLAG_FD_OUTPUT  |\
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		       PERF_FLAG_PID_CGROUP |\
		       PERF_FLAG_FD_CLOEXEC)
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/*
 * branch priv levels that need permission checks
 */
#define PERF_SAMPLE_BRANCH_PERM_PLM \
	(PERF_SAMPLE_BRANCH_KERNEL |\
	 PERF_SAMPLE_BRANCH_HV)

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enum event_type_t {
	EVENT_FLEXIBLE = 0x1,
	EVENT_PINNED = 0x2,
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	EVENT_TIME = 0x4,
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	EVENT_ALL = EVENT_FLEXIBLE | EVENT_PINNED,
};

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/*
 * perf_sched_events : >0 events exist
 * perf_cgroup_events: >0 per-cpu cgroup events exist on this cpu
 */
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static void perf_sched_delayed(struct work_struct *work);
DEFINE_STATIC_KEY_FALSE(perf_sched_events);
static DECLARE_DELAYED_WORK(perf_sched_work, perf_sched_delayed);
static DEFINE_MUTEX(perf_sched_mutex);
static atomic_t perf_sched_count;

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static DEFINE_PER_CPU(atomic_t, perf_cgroup_events);
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static DEFINE_PER_CPU(int, perf_sched_cb_usages);
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static DEFINE_PER_CPU(struct pmu_event_list, pmu_sb_events);
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static atomic_t nr_mmap_events __read_mostly;
static atomic_t nr_comm_events __read_mostly;
static atomic_t nr_task_events __read_mostly;
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static atomic_t nr_freq_events __read_mostly;
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static atomic_t nr_switch_events __read_mostly;
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static LIST_HEAD(pmus);
static DEFINE_MUTEX(pmus_lock);
static struct srcu_struct pmus_srcu;

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/*
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 * perf event paranoia level:
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 *  -1 - not paranoid at all
 *   0 - disallow raw tracepoint access for unpriv
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 *   1 - disallow cpu events for unpriv
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 *   2 - disallow kernel profiling for unpriv
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 */
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int sysctl_perf_event_paranoid __read_mostly = 2;
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/* Minimum for 512 kiB + 1 user control page */
int sysctl_perf_event_mlock __read_mostly = 512 + (PAGE_SIZE / 1024); /* 'free' kiB per user */
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/*
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 * max perf event sample rate
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 */
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#define DEFAULT_MAX_SAMPLE_RATE		100000
#define DEFAULT_SAMPLE_PERIOD_NS	(NSEC_PER_SEC / DEFAULT_MAX_SAMPLE_RATE)
#define DEFAULT_CPU_TIME_MAX_PERCENT	25

int sysctl_perf_event_sample_rate __read_mostly	= DEFAULT_MAX_SAMPLE_RATE;

static int max_samples_per_tick __read_mostly	= DIV_ROUND_UP(DEFAULT_MAX_SAMPLE_RATE, HZ);
static int perf_sample_period_ns __read_mostly	= DEFAULT_SAMPLE_PERIOD_NS;

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static int perf_sample_allowed_ns __read_mostly =
	DEFAULT_SAMPLE_PERIOD_NS * DEFAULT_CPU_TIME_MAX_PERCENT / 100;
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static void update_perf_cpu_limits(void)
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{
	u64 tmp = perf_sample_period_ns;

	tmp *= sysctl_perf_cpu_time_max_percent;
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	tmp = div_u64(tmp, 100);
	if (!tmp)
		tmp = 1;

	WRITE_ONCE(perf_sample_allowed_ns, tmp);
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}
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static int perf_rotate_context(struct perf_cpu_context *cpuctx);

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int perf_proc_update_handler(struct ctl_table *table, int write,
		void __user *buffer, size_t *lenp,
		loff_t *ppos)
{
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	int ret = proc_dointvec_minmax(table, write, buffer, lenp, ppos);
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	if (ret || !write)
		return ret;

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	/*
	 * If throttling is disabled don't allow the write:
	 */
	if (sysctl_perf_cpu_time_max_percent == 100 ||
	    sysctl_perf_cpu_time_max_percent == 0)
		return -EINVAL;

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	max_samples_per_tick = DIV_ROUND_UP(sysctl_perf_event_sample_rate, HZ);
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	perf_sample_period_ns = NSEC_PER_SEC / sysctl_perf_event_sample_rate;
	update_perf_cpu_limits();

	return 0;
}

int sysctl_perf_cpu_time_max_percent __read_mostly = DEFAULT_CPU_TIME_MAX_PERCENT;

int perf_cpu_time_max_percent_handler(struct ctl_table *table, int write,
				void __user *buffer, size_t *lenp,
				loff_t *ppos)
{
	int ret = proc_dointvec(table, write, buffer, lenp, ppos);

	if (ret || !write)
		return ret;

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	if (sysctl_perf_cpu_time_max_percent == 100 ||
	    sysctl_perf_cpu_time_max_percent == 0) {
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		printk(KERN_WARNING
		       "perf: Dynamic interrupt throttling disabled, can hang your system!\n");
		WRITE_ONCE(perf_sample_allowed_ns, 0);
	} else {
		update_perf_cpu_limits();
	}
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	return 0;
}
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/*
 * perf samples are done in some very critical code paths (NMIs).
 * If they take too much CPU time, the system can lock up and not
 * get any real work done.  This will drop the sample rate when
 * we detect that events are taking too long.
 */
#define NR_ACCUMULATED_SAMPLES 128
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static DEFINE_PER_CPU(u64, running_sample_length);
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static u64 __report_avg;
static u64 __report_allowed;

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static void perf_duration_warn(struct irq_work *w)
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{
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	printk_ratelimited(KERN_INFO
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		"perf: interrupt took too long (%lld > %lld), lowering "
		"kernel.perf_event_max_sample_rate to %d\n",
		__report_avg, __report_allowed,
		sysctl_perf_event_sample_rate);
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}

static DEFINE_IRQ_WORK(perf_duration_work, perf_duration_warn);

void perf_sample_event_took(u64 sample_len_ns)
{
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	u64 max_len = READ_ONCE(perf_sample_allowed_ns);
	u64 running_len;
	u64 avg_len;
	u32 max;
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	if (max_len == 0)
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		return;

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	/* Decay the counter by 1 average sample. */
	running_len = __this_cpu_read(running_sample_length);
	running_len -= running_len/NR_ACCUMULATED_SAMPLES;
	running_len += sample_len_ns;
	__this_cpu_write(running_sample_length, running_len);
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	/*
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	 * Note: this will be biased artifically low until we have
	 * seen NR_ACCUMULATED_SAMPLES. Doing it this way keeps us
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	 * from having to maintain a count.
	 */
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	avg_len = running_len/NR_ACCUMULATED_SAMPLES;
	if (avg_len <= max_len)
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		return;

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	__report_avg = avg_len;
	__report_allowed = max_len;
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	/*
	 * Compute a throttle threshold 25% below the current duration.
	 */
	avg_len += avg_len / 4;
	max = (TICK_NSEC / 100) * sysctl_perf_cpu_time_max_percent;
	if (avg_len < max)
		max /= (u32)avg_len;
	else
		max = 1;
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	WRITE_ONCE(perf_sample_allowed_ns, avg_len);
	WRITE_ONCE(max_samples_per_tick, max);

	sysctl_perf_event_sample_rate = max * HZ;
	perf_sample_period_ns = NSEC_PER_SEC / sysctl_perf_event_sample_rate;
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	if (!irq_work_queue(&perf_duration_work)) {
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		early_printk("perf: interrupt took too long (%lld > %lld), lowering "
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			     "kernel.perf_event_max_sample_rate to %d\n",
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			     __report_avg, __report_allowed,
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			     sysctl_perf_event_sample_rate);
	}
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}

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static atomic64_t perf_event_id;
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static void cpu_ctx_sched_out(struct perf_cpu_context *cpuctx,
			      enum event_type_t event_type);

static void cpu_ctx_sched_in(struct perf_cpu_context *cpuctx,
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			     enum event_type_t event_type,
			     struct task_struct *task);

static void update_context_time(struct perf_event_context *ctx);
static u64 perf_event_time(struct perf_event *event);
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void __weak perf_event_print_debug(void)	{ }
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extern __weak const char *perf_pmu_name(void)
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{
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	return "pmu";
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}

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static inline u64 perf_clock(void)
{
	return local_clock();
}

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static inline u64 perf_event_clock(struct perf_event *event)
{
	return event->clock();
}

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#ifdef CONFIG_CGROUP_PERF

static inline bool
perf_cgroup_match(struct perf_event *event)
{
	struct perf_event_context *ctx = event->ctx;
	struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);

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	/* @event doesn't care about cgroup */
	if (!event->cgrp)
		return true;

	/* wants specific cgroup scope but @cpuctx isn't associated with any */
	if (!cpuctx->cgrp)
		return false;

	/*
	 * Cgroup scoping is recursive.  An event enabled for a cgroup is
	 * also enabled for all its descendant cgroups.  If @cpuctx's
	 * cgroup is a descendant of @event's (the test covers identity
	 * case), it's a match.
	 */
	return cgroup_is_descendant(cpuctx->cgrp->css.cgroup,
				    event->cgrp->css.cgroup);
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}

static inline void perf_detach_cgroup(struct perf_event *event)
{
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	css_put(&event->cgrp->css);
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	event->cgrp = NULL;
}

static inline int is_cgroup_event(struct perf_event *event)
{
	return event->cgrp != NULL;
}

static inline u64 perf_cgroup_event_time(struct perf_event *event)
{
	struct perf_cgroup_info *t;

	t = per_cpu_ptr(event->cgrp->info, event->cpu);
	return t->time;
}

static inline void __update_cgrp_time(struct perf_cgroup *cgrp)
{
	struct perf_cgroup_info *info;
	u64 now;

	now = perf_clock();

	info = this_cpu_ptr(cgrp->info);

	info->time += now - info->timestamp;
	info->timestamp = now;
}

static inline void update_cgrp_time_from_cpuctx(struct perf_cpu_context *cpuctx)
{
	struct perf_cgroup *cgrp_out = cpuctx->cgrp;
	if (cgrp_out)
		__update_cgrp_time(cgrp_out);
}

static inline void update_cgrp_time_from_event(struct perf_event *event)
{
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	struct perf_cgroup *cgrp;

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	/*
647 648
	 * ensure we access cgroup data only when needed and
	 * when we know the cgroup is pinned (css_get)
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649
	 */
650
	if (!is_cgroup_event(event))
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		return;

653
	cgrp = perf_cgroup_from_task(current, event->ctx);
654 655 656 657 658
	/*
	 * Do not update time when cgroup is not active
	 */
	if (cgrp == event->cgrp)
		__update_cgrp_time(event->cgrp);
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}

static inline void
662 663
perf_cgroup_set_timestamp(struct task_struct *task,
			  struct perf_event_context *ctx)
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{
	struct perf_cgroup *cgrp;
	struct perf_cgroup_info *info;

668 669 670 671 672 673
	/*
	 * ctx->lock held by caller
	 * ensure we do not access cgroup data
	 * unless we have the cgroup pinned (css_get)
	 */
	if (!task || !ctx->nr_cgroups)
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		return;

676
	cgrp = perf_cgroup_from_task(task, ctx);
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	info = this_cpu_ptr(cgrp->info);
678
	info->timestamp = ctx->timestamp;
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}

#define PERF_CGROUP_SWOUT	0x1 /* cgroup switch out every event */
#define PERF_CGROUP_SWIN	0x2 /* cgroup switch in events based on task */

/*
 * reschedule events based on the cgroup constraint of task.
 *
 * mode SWOUT : schedule out everything
 * mode SWIN : schedule in based on cgroup for next
 */
690
static void perf_cgroup_switch(struct task_struct *task, int mode)
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{
	struct perf_cpu_context *cpuctx;
	struct pmu *pmu;
	unsigned long flags;

	/*
	 * disable interrupts to avoid geting nr_cgroup
	 * changes via __perf_event_disable(). Also
	 * avoids preemption.
	 */
	local_irq_save(flags);

	/*
	 * we reschedule only in the presence of cgroup
	 * constrained events.
	 */

	list_for_each_entry_rcu(pmu, &pmus, entry) {
		cpuctx = this_cpu_ptr(pmu->pmu_cpu_context);
710 711
		if (cpuctx->unique_pmu != pmu)
			continue; /* ensure we process each cpuctx once */
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		/*
		 * perf_cgroup_events says at least one
		 * context on this CPU has cgroup events.
		 *
		 * ctx->nr_cgroups reports the number of cgroup
		 * events for a context.
		 */
		if (cpuctx->ctx.nr_cgroups > 0) {
721 722
			perf_ctx_lock(cpuctx, cpuctx->task_ctx);
			perf_pmu_disable(cpuctx->ctx.pmu);
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			if (mode & PERF_CGROUP_SWOUT) {
				cpu_ctx_sched_out(cpuctx, EVENT_ALL);
				/*
				 * must not be done before ctxswout due
				 * to event_filter_match() in event_sched_out()
				 */
				cpuctx->cgrp = NULL;
			}

			if (mode & PERF_CGROUP_SWIN) {
734
				WARN_ON_ONCE(cpuctx->cgrp);
735 736 737 738
				/*
				 * set cgrp before ctxsw in to allow
				 * event_filter_match() to not have to pass
				 * task around
739 740
				 * we pass the cpuctx->ctx to perf_cgroup_from_task()
				 * because cgorup events are only per-cpu
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				 */
742
				cpuctx->cgrp = perf_cgroup_from_task(task, &cpuctx->ctx);
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				cpu_ctx_sched_in(cpuctx, EVENT_ALL, task);
			}
745 746
			perf_pmu_enable(cpuctx->ctx.pmu);
			perf_ctx_unlock(cpuctx, cpuctx->task_ctx);
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		}
	}

	local_irq_restore(flags);
}

753 754
static inline void perf_cgroup_sched_out(struct task_struct *task,
					 struct task_struct *next)
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{
756 757 758
	struct perf_cgroup *cgrp1;
	struct perf_cgroup *cgrp2 = NULL;

759
	rcu_read_lock();
760 761
	/*
	 * we come here when we know perf_cgroup_events > 0
762 763
	 * we do not need to pass the ctx here because we know
	 * we are holding the rcu lock
764
	 */
765
	cgrp1 = perf_cgroup_from_task(task, NULL);
766
	cgrp2 = perf_cgroup_from_task(next, NULL);
767 768 769 770 771 772 773 774

	/*
	 * only schedule out current cgroup events if we know
	 * that we are switching to a different cgroup. Otherwise,
	 * do no touch the cgroup events.
	 */
	if (cgrp1 != cgrp2)
		perf_cgroup_switch(task, PERF_CGROUP_SWOUT);
775 776

	rcu_read_unlock();
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}

779 780
static inline void perf_cgroup_sched_in(struct task_struct *prev,
					struct task_struct *task)
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{
782 783 784
	struct perf_cgroup *cgrp1;
	struct perf_cgroup *cgrp2 = NULL;

785
	rcu_read_lock();
786 787
	/*
	 * we come here when we know perf_cgroup_events > 0
788 789
	 * we do not need to pass the ctx here because we know
	 * we are holding the rcu lock
790
	 */
791 792
	cgrp1 = perf_cgroup_from_task(task, NULL);
	cgrp2 = perf_cgroup_from_task(prev, NULL);
793 794 795 796 797 798 799 800

	/*
	 * only need to schedule in cgroup events if we are changing
	 * cgroup during ctxsw. Cgroup events were not scheduled
	 * out of ctxsw out if that was not the case.
	 */
	if (cgrp1 != cgrp2)
		perf_cgroup_switch(task, PERF_CGROUP_SWIN);
801 802

	rcu_read_unlock();
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}

static inline int perf_cgroup_connect(int fd, struct perf_event *event,
				      struct perf_event_attr *attr,
				      struct perf_event *group_leader)
{
	struct perf_cgroup *cgrp;
	struct cgroup_subsys_state *css;
811 812
	struct fd f = fdget(fd);
	int ret = 0;
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814
	if (!f.file)
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815 816
		return -EBADF;

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	css = css_tryget_online_from_dir(f.file->f_path.dentry,
818
					 &perf_event_cgrp_subsys);
819 820 821 822
	if (IS_ERR(css)) {
		ret = PTR_ERR(css);
		goto out;
	}
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	cgrp = container_of(css, struct perf_cgroup, css);
	event->cgrp = cgrp;

	/*
	 * all events in a group must monitor
	 * the same cgroup because a task belongs
	 * to only one perf cgroup at a time
	 */
	if (group_leader && group_leader->cgrp != cgrp) {
		perf_detach_cgroup(event);
		ret = -EINVAL;
	}
836
out:
837
	fdput(f);
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	return ret;
}

static inline void
perf_cgroup_set_shadow_time(struct perf_event *event, u64 now)
{
	struct perf_cgroup_info *t;
	t = per_cpu_ptr(event->cgrp->info, event->cpu);
	event->shadow_ctx_time = now - t->timestamp;
}

static inline void
perf_cgroup_defer_enabled(struct perf_event *event)
{
	/*
	 * when the current task's perf cgroup does not match
	 * the event's, we need to remember to call the
	 * perf_mark_enable() function the first time a task with
	 * a matching perf cgroup is scheduled in.
	 */
	if (is_cgroup_event(event) && !perf_cgroup_match(event))
		event->cgrp_defer_enabled = 1;
}

static inline void
perf_cgroup_mark_enabled(struct perf_event *event,
			 struct perf_event_context *ctx)
{
	struct perf_event *sub;
	u64 tstamp = perf_event_time(event);

	if (!event->cgrp_defer_enabled)
		return;

	event->cgrp_defer_enabled = 0;

	event->tstamp_enabled = tstamp - event->total_time_enabled;
	list_for_each_entry(sub, &event->sibling_list, group_entry) {
		if (sub->state >= PERF_EVENT_STATE_INACTIVE) {
			sub->tstamp_enabled = tstamp - sub->total_time_enabled;
			sub->cgrp_defer_enabled = 0;
		}
	}
}
882 883 884 885 886 887 888 889 890 891 892 893 894 895 896 897 898 899 900 901 902 903 904 905 906 907

/*
 * Update cpuctx->cgrp so that it is set when first cgroup event is added and
 * cleared when last cgroup event is removed.
 */
static inline void
list_update_cgroup_event(struct perf_event *event,
			 struct perf_event_context *ctx, bool add)
{
	struct perf_cpu_context *cpuctx;

	if (!is_cgroup_event(event))
		return;

	if (add && ctx->nr_cgroups++)
		return;
	else if (!add && --ctx->nr_cgroups)
		return;
	/*
	 * Because cgroup events are always per-cpu events,
	 * this will always be called from the right CPU.
	 */
	cpuctx = __get_cpu_context(ctx);
	cpuctx->cgrp = add ? event->cgrp : NULL;
}

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#else /* !CONFIG_CGROUP_PERF */

static inline bool
perf_cgroup_match(struct perf_event *event)
{
	return true;
}

static inline void perf_detach_cgroup(struct perf_event *event)
{}

static inline int is_cgroup_event(struct perf_event *event)
{
	return 0;
}

static inline u64 perf_cgroup_event_cgrp_time(struct perf_event *event)
{
	return 0;
}

static inline void update_cgrp_time_from_event(struct perf_event *event)
{
}

static inline void update_cgrp_time_from_cpuctx(struct perf_cpu_context *cpuctx)
{
}

937 938
static inline void perf_cgroup_sched_out(struct task_struct *task,
					 struct task_struct *next)
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939 940 941
{
}

942 943
static inline void perf_cgroup_sched_in(struct task_struct *prev,
					struct task_struct *task)
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944 945 946 947 948 949 950 951 952 953 954
{
}

static inline int perf_cgroup_connect(pid_t pid, struct perf_event *event,
				      struct perf_event_attr *attr,
				      struct perf_event *group_leader)
{
	return -EINVAL;
}

static inline void
955 956
perf_cgroup_set_timestamp(struct task_struct *task,
			  struct perf_event_context *ctx)
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957 958 959 960 961 962 963 964 965 966 967 968 969 970 971 972 973 974 975 976 977 978 979 980 981 982 983 984
{
}

void
perf_cgroup_switch(struct task_struct *task, struct task_struct *next)
{
}

static inline void
perf_cgroup_set_shadow_time(struct perf_event *event, u64 now)
{
}

static inline u64 perf_cgroup_event_time(struct perf_event *event)
{
	return 0;
}

static inline void
perf_cgroup_defer_enabled(struct perf_event *event)
{
}

static inline void
perf_cgroup_mark_enabled(struct perf_event *event,
			 struct perf_event_context *ctx)
{
}
985 986 987 988 989 990 991

static inline void
list_update_cgroup_event(struct perf_event *event,
			 struct perf_event_context *ctx, bool add)
{
}

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992 993
#endif

994 995 996 997 998 999 1000 1001
/*
 * set default to be dependent on timer tick just
 * like original code
 */
#define PERF_CPU_HRTIMER (1000 / HZ)
/*
 * function must be called with interrupts disbled
 */
1002
static enum hrtimer_restart perf_mux_hrtimer_handler(struct hrtimer *hr)
1003 1004 1005 1006 1007 1008 1009 1010 1011
{
	struct perf_cpu_context *cpuctx;
	int rotations = 0;

	WARN_ON(!irqs_disabled());

	cpuctx = container_of(hr, struct perf_cpu_context, hrtimer);
	rotations = perf_rotate_context(cpuctx);

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	raw_spin_lock(&cpuctx->hrtimer_lock);
	if (rotations)
1014
		hrtimer_forward_now(hr, cpuctx->hrtimer_interval);
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	else
		cpuctx->hrtimer_active = 0;
	raw_spin_unlock(&cpuctx->hrtimer_lock);
1018

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1019
	return rotations ? HRTIMER_RESTART : HRTIMER_NORESTART;
1020 1021
}

1022
static void __perf_mux_hrtimer_init(struct perf_cpu_context *cpuctx, int cpu)
1023
{
1024
	struct hrtimer *timer = &cpuctx->hrtimer;
1025
	struct pmu *pmu = cpuctx->ctx.pmu;
1026
	u64 interval;
1027 1028 1029 1030 1031

	/* no multiplexing needed for SW PMU */
	if (pmu->task_ctx_nr == perf_sw_context)
		return;

1032 1033 1034 1035
	/*
	 * check default is sane, if not set then force to
	 * default interval (1/tick)
	 */
1036 1037 1038
	interval = pmu->hrtimer_interval_ms;
	if (interval < 1)
		interval = pmu->hrtimer_interval_ms = PERF_CPU_HRTIMER;
1039

1040
	cpuctx->hrtimer_interval = ns_to_ktime(NSEC_PER_MSEC * interval);
1041

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Peter Zijlstra 已提交
1042 1043
	raw_spin_lock_init(&cpuctx->hrtimer_lock);
	hrtimer_init(timer, CLOCK_MONOTONIC, HRTIMER_MODE_ABS_PINNED);
1044
	timer->function = perf_mux_hrtimer_handler;
1045 1046
}

1047
static int perf_mux_hrtimer_restart(struct perf_cpu_context *cpuctx)
1048
{
1049
	struct hrtimer *timer = &cpuctx->hrtimer;
1050
	struct pmu *pmu = cpuctx->ctx.pmu;
P
Peter Zijlstra 已提交
1051
	unsigned long flags;
1052 1053 1054

	/* not for SW PMU */
	if (pmu->task_ctx_nr == perf_sw_context)
1055
		return 0;
1056

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1057 1058 1059 1060 1061 1062 1063
	raw_spin_lock_irqsave(&cpuctx->hrtimer_lock, flags);
	if (!cpuctx->hrtimer_active) {
		cpuctx->hrtimer_active = 1;
		hrtimer_forward_now(timer, cpuctx->hrtimer_interval);
		hrtimer_start_expires(timer, HRTIMER_MODE_ABS_PINNED);
	}
	raw_spin_unlock_irqrestore(&cpuctx->hrtimer_lock, flags);
1064

1065
	return 0;
1066 1067
}

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1068
void perf_pmu_disable(struct pmu *pmu)
1069
{
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Peter Zijlstra 已提交
1070 1071 1072
	int *count = this_cpu_ptr(pmu->pmu_disable_count);
	if (!(*count)++)
		pmu->pmu_disable(pmu);
1073 1074
}

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1075
void perf_pmu_enable(struct pmu *pmu)
1076
{
P
Peter Zijlstra 已提交
1077 1078 1079
	int *count = this_cpu_ptr(pmu->pmu_disable_count);
	if (!--(*count))
		pmu->pmu_enable(pmu);
1080 1081
}

1082
static DEFINE_PER_CPU(struct list_head, active_ctx_list);
1083 1084

/*
1085 1086 1087 1088
 * perf_event_ctx_activate(), perf_event_ctx_deactivate(), and
 * perf_event_task_tick() are fully serialized because they're strictly cpu
 * affine and perf_event_ctx{activate,deactivate} are called with IRQs
 * disabled, while perf_event_task_tick is called from IRQ context.
1089
 */
1090
static void perf_event_ctx_activate(struct perf_event_context *ctx)
1091
{
1092
	struct list_head *head = this_cpu_ptr(&active_ctx_list);
1093

1094
	WARN_ON(!irqs_disabled());
1095

1096 1097 1098 1099 1100 1101 1102 1103 1104 1105 1106 1107
	WARN_ON(!list_empty(&ctx->active_ctx_list));

	list_add(&ctx->active_ctx_list, head);
}

static void perf_event_ctx_deactivate(struct perf_event_context *ctx)
{
	WARN_ON(!irqs_disabled());

	WARN_ON(list_empty(&ctx->active_ctx_list));

	list_del_init(&ctx->active_ctx_list);
1108 1109
}

1110
static void get_ctx(struct perf_event_context *ctx)
1111
{
1112
	WARN_ON(!atomic_inc_not_zero(&ctx->refcount));
1113 1114
}

1115 1116 1117 1118 1119 1120 1121 1122 1123
static void free_ctx(struct rcu_head *head)
{
	struct perf_event_context *ctx;

	ctx = container_of(head, struct perf_event_context, rcu_head);
	kfree(ctx->task_ctx_data);
	kfree(ctx);
}

1124
static void put_ctx(struct perf_event_context *ctx)
1125
{
1126 1127 1128
	if (atomic_dec_and_test(&ctx->refcount)) {
		if (ctx->parent_ctx)
			put_ctx(ctx->parent_ctx);
1129
		if (ctx->task && ctx->task != TASK_TOMBSTONE)
1130
			put_task_struct(ctx->task);
1131
		call_rcu(&ctx->rcu_head, free_ctx);
1132
	}
1133 1134
}

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1135 1136 1137 1138 1139 1140 1141
/*
 * Because of perf_event::ctx migration in sys_perf_event_open::move_group and
 * perf_pmu_migrate_context() we need some magic.
 *
 * Those places that change perf_event::ctx will hold both
 * perf_event_ctx::mutex of the 'old' and 'new' ctx value.
 *
1142 1143 1144 1145
 * Lock ordering is by mutex address. There are two other sites where
 * perf_event_context::mutex nests and those are:
 *
 *  - perf_event_exit_task_context()	[ child , 0 ]
1146 1147
 *      perf_event_exit_event()
 *        put_event()			[ parent, 1 ]
1148 1149 1150 1151 1152 1153 1154 1155 1156 1157 1158 1159 1160 1161 1162 1163 1164
 *
 *  - perf_event_init_context()		[ parent, 0 ]
 *      inherit_task_group()
 *        inherit_group()
 *          inherit_event()
 *            perf_event_alloc()
 *              perf_init_event()
 *                perf_try_init_event()	[ child , 1 ]
 *
 * While it appears there is an obvious deadlock here -- the parent and child
 * nesting levels are inverted between the two. This is in fact safe because
 * life-time rules separate them. That is an exiting task cannot fork, and a
 * spawning task cannot (yet) exit.
 *
 * But remember that that these are parent<->child context relations, and
 * migration does not affect children, therefore these two orderings should not
 * interact.
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1165 1166 1167 1168 1169 1170 1171 1172 1173 1174 1175 1176 1177 1178 1179 1180 1181 1182 1183 1184 1185 1186 1187
 *
 * The change in perf_event::ctx does not affect children (as claimed above)
 * because the sys_perf_event_open() case will install a new event and break
 * the ctx parent<->child relation, and perf_pmu_migrate_context() is only
 * concerned with cpuctx and that doesn't have children.
 *
 * The places that change perf_event::ctx will issue:
 *
 *   perf_remove_from_context();
 *   synchronize_rcu();
 *   perf_install_in_context();
 *
 * to affect the change. The remove_from_context() + synchronize_rcu() should
 * quiesce the event, after which we can install it in the new location. This
 * means that only external vectors (perf_fops, prctl) can perturb the event
 * while in transit. Therefore all such accessors should also acquire
 * perf_event_context::mutex to serialize against this.
 *
 * However; because event->ctx can change while we're waiting to acquire
 * ctx->mutex we must be careful and use the below perf_event_ctx_lock()
 * function.
 *
 * Lock order:
1188
 *    cred_guard_mutex
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1189 1190 1191
 *	task_struct::perf_event_mutex
 *	  perf_event_context::mutex
 *	    perf_event::child_mutex;
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1192
 *	      perf_event_context::lock
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1193 1194 1195
 *	    perf_event::mmap_mutex
 *	    mmap_sem
 */
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1196 1197
static struct perf_event_context *
perf_event_ctx_lock_nested(struct perf_event *event, int nesting)
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1198 1199 1200 1201 1202 1203 1204 1205 1206 1207 1208 1209
{
	struct perf_event_context *ctx;

again:
	rcu_read_lock();
	ctx = ACCESS_ONCE(event->ctx);
	if (!atomic_inc_not_zero(&ctx->refcount)) {
		rcu_read_unlock();
		goto again;
	}
	rcu_read_unlock();

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1210
	mutex_lock_nested(&ctx->mutex, nesting);
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1211 1212 1213 1214 1215 1216 1217 1218 1219
	if (event->ctx != ctx) {
		mutex_unlock(&ctx->mutex);
		put_ctx(ctx);
		goto again;
	}

	return ctx;
}

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static inline struct perf_event_context *
perf_event_ctx_lock(struct perf_event *event)
{
	return perf_event_ctx_lock_nested(event, 0);
}

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1226 1227 1228 1229 1230 1231 1232
static void perf_event_ctx_unlock(struct perf_event *event,
				  struct perf_event_context *ctx)
{
	mutex_unlock(&ctx->mutex);
	put_ctx(ctx);
}

1233 1234 1235 1236 1237 1238 1239
/*
 * This must be done under the ctx->lock, such as to serialize against
 * context_equiv(), therefore we cannot call put_ctx() since that might end up
 * calling scheduler related locks and ctx->lock nests inside those.
 */
static __must_check struct perf_event_context *
unclone_ctx(struct perf_event_context *ctx)
1240
{
1241 1242 1243 1244 1245
	struct perf_event_context *parent_ctx = ctx->parent_ctx;

	lockdep_assert_held(&ctx->lock);

	if (parent_ctx)
1246
		ctx->parent_ctx = NULL;
1247
	ctx->generation++;
1248 1249

	return parent_ctx;
1250 1251
}

1252 1253 1254 1255 1256 1257 1258 1259 1260 1261 1262 1263 1264 1265 1266 1267 1268 1269 1270 1271 1272 1273
static u32 perf_event_pid(struct perf_event *event, struct task_struct *p)
{
	/*
	 * only top level events have the pid namespace they were created in
	 */
	if (event->parent)
		event = event->parent;

	return task_tgid_nr_ns(p, event->ns);
}

static u32 perf_event_tid(struct perf_event *event, struct task_struct *p)
{
	/*
	 * only top level events have the pid namespace they were created in
	 */
	if (event->parent)
		event = event->parent;

	return task_pid_nr_ns(p, event->ns);
}

1274
/*
1275
 * If we inherit events we want to return the parent event id
1276 1277
 * to userspace.
 */
1278
static u64 primary_event_id(struct perf_event *event)
1279
{
1280
	u64 id = event->id;
1281

1282 1283
	if (event->parent)
		id = event->parent->id;
1284 1285 1286 1287

	return id;
}

1288
/*
1289
 * Get the perf_event_context for a task and lock it.
1290
 *
1291 1292 1293
 * This has to cope with with the fact that until it is locked,
 * the context could get moved to another task.
 */
1294
static struct perf_event_context *
P
Peter Zijlstra 已提交
1295
perf_lock_task_context(struct task_struct *task, int ctxn, unsigned long *flags)
1296
{
1297
	struct perf_event_context *ctx;
1298

P
Peter Zijlstra 已提交
1299
retry:
1300 1301 1302
	/*
	 * One of the few rules of preemptible RCU is that one cannot do
	 * rcu_read_unlock() while holding a scheduler (or nested) lock when
1303
	 * part of the read side critical section was irqs-enabled -- see
1304 1305 1306
	 * rcu_read_unlock_special().
	 *
	 * Since ctx->lock nests under rq->lock we must ensure the entire read
1307
	 * side critical section has interrupts disabled.
1308
	 */
1309
	local_irq_save(*flags);
1310
	rcu_read_lock();
P
Peter Zijlstra 已提交
1311
	ctx = rcu_dereference(task->perf_event_ctxp[ctxn]);
1312 1313 1314 1315
	if (ctx) {
		/*
		 * If this context is a clone of another, it might
		 * get swapped for another underneath us by
1316
		 * perf_event_task_sched_out, though the
1317 1318 1319 1320 1321 1322
		 * rcu_read_lock() protects us from any context
		 * getting freed.  Lock the context and check if it
		 * got swapped before we could get the lock, and retry
		 * if so.  If we locked the right context, then it
		 * can't get swapped on us any more.
		 */
1323
		raw_spin_lock(&ctx->lock);
P
Peter Zijlstra 已提交
1324
		if (ctx != rcu_dereference(task->perf_event_ctxp[ctxn])) {
1325
			raw_spin_unlock(&ctx->lock);
1326
			rcu_read_unlock();
1327
			local_irq_restore(*flags);
1328 1329
			goto retry;
		}
1330

1331 1332
		if (ctx->task == TASK_TOMBSTONE ||
		    !atomic_inc_not_zero(&ctx->refcount)) {
1333
			raw_spin_unlock(&ctx->lock);
1334
			ctx = NULL;
P
Peter Zijlstra 已提交
1335 1336
		} else {
			WARN_ON_ONCE(ctx->task != task);
1337
		}
1338 1339
	}
	rcu_read_unlock();
1340 1341
	if (!ctx)
		local_irq_restore(*flags);
1342 1343 1344 1345 1346 1347 1348 1349
	return ctx;
}

/*
 * Get the context for a task and increment its pin_count so it
 * can't get swapped to another task.  This also increments its
 * reference count so that the context can't get freed.
 */
P
Peter Zijlstra 已提交
1350 1351
static struct perf_event_context *
perf_pin_task_context(struct task_struct *task, int ctxn)
1352
{
1353
	struct perf_event_context *ctx;
1354 1355
	unsigned long flags;

P
Peter Zijlstra 已提交
1356
	ctx = perf_lock_task_context(task, ctxn, &flags);
1357 1358
	if (ctx) {
		++ctx->pin_count;
1359
		raw_spin_unlock_irqrestore(&ctx->lock, flags);
1360 1361 1362 1363
	}
	return ctx;
}

1364
static void perf_unpin_context(struct perf_event_context *ctx)
1365 1366 1367
{
	unsigned long flags;

1368
	raw_spin_lock_irqsave(&ctx->lock, flags);
1369
	--ctx->pin_count;
1370
	raw_spin_unlock_irqrestore(&ctx->lock, flags);
1371 1372
}

1373 1374 1375 1376 1377 1378 1379 1380 1381 1382 1383
/*
 * Update the record of the current time in a context.
 */
static void update_context_time(struct perf_event_context *ctx)
{
	u64 now = perf_clock();

	ctx->time += now - ctx->timestamp;
	ctx->timestamp = now;
}

1384 1385 1386
static u64 perf_event_time(struct perf_event *event)
{
	struct perf_event_context *ctx = event->ctx;
S
Stephane Eranian 已提交
1387 1388 1389 1390

	if (is_cgroup_event(event))
		return perf_cgroup_event_time(event);

1391 1392 1393
	return ctx ? ctx->time : 0;
}

1394 1395 1396 1397 1398 1399 1400 1401
/*
 * Update the total_time_enabled and total_time_running fields for a event.
 */
static void update_event_times(struct perf_event *event)
{
	struct perf_event_context *ctx = event->ctx;
	u64 run_end;

1402 1403
	lockdep_assert_held(&ctx->lock);

1404 1405 1406
	if (event->state < PERF_EVENT_STATE_INACTIVE ||
	    event->group_leader->state < PERF_EVENT_STATE_INACTIVE)
		return;
1407

S
Stephane Eranian 已提交
1408 1409 1410 1411 1412 1413 1414 1415 1416 1417 1418
	/*
	 * in cgroup mode, time_enabled represents
	 * the time the event was enabled AND active
	 * tasks were in the monitored cgroup. This is
	 * independent of the activity of the context as
	 * there may be a mix of cgroup and non-cgroup events.
	 *
	 * That is why we treat cgroup events differently
	 * here.
	 */
	if (is_cgroup_event(event))
1419
		run_end = perf_cgroup_event_time(event);
S
Stephane Eranian 已提交
1420 1421
	else if (ctx->is_active)
		run_end = ctx->time;
1422 1423 1424 1425
	else
		run_end = event->tstamp_stopped;

	event->total_time_enabled = run_end - event->tstamp_enabled;
1426 1427 1428 1429

	if (event->state == PERF_EVENT_STATE_INACTIVE)
		run_end = event->tstamp_stopped;
	else
1430
		run_end = perf_event_time(event);
1431 1432

	event->total_time_running = run_end - event->tstamp_running;
S
Stephane Eranian 已提交
1433

1434 1435
}

1436 1437 1438 1439 1440 1441 1442 1443 1444 1445 1446 1447
/*
 * Update total_time_enabled and total_time_running for all events in a group.
 */
static void update_group_times(struct perf_event *leader)
{
	struct perf_event *event;

	update_event_times(leader);
	list_for_each_entry(event, &leader->sibling_list, group_entry)
		update_event_times(event);
}

1448 1449 1450 1451 1452 1453 1454 1455 1456
static struct list_head *
ctx_group_list(struct perf_event *event, struct perf_event_context *ctx)
{
	if (event->attr.pinned)
		return &ctx->pinned_groups;
	else
		return &ctx->flexible_groups;
}

1457
/*
1458
 * Add a event from the lists for its context.
1459 1460
 * Must be called with ctx->mutex and ctx->lock held.
 */
1461
static void
1462
list_add_event(struct perf_event *event, struct perf_event_context *ctx)
1463
{
1464

P
Peter Zijlstra 已提交
1465 1466
	lockdep_assert_held(&ctx->lock);

1467 1468
	WARN_ON_ONCE(event->attach_state & PERF_ATTACH_CONTEXT);
	event->attach_state |= PERF_ATTACH_CONTEXT;
1469 1470

	/*
1471 1472 1473
	 * If we're a stand alone event or group leader, we go to the context
	 * list, group events are kept attached to the group so that
	 * perf_group_detach can, at all times, locate all siblings.
1474
	 */
1475
	if (event->group_leader == event) {
1476 1477
		struct list_head *list;

1478
		event->group_caps = event->event_caps;
1479

1480 1481
		list = ctx_group_list(event, ctx);
		list_add_tail(&event->group_entry, list);
P
Peter Zijlstra 已提交
1482
	}
P
Peter Zijlstra 已提交
1483

1484
	list_update_cgroup_event(event, ctx, true);
S
Stephane Eranian 已提交
1485

1486 1487 1488
	list_add_rcu(&event->event_entry, &ctx->event_list);
	ctx->nr_events++;
	if (event->attr.inherit_stat)
1489
		ctx->nr_stat++;
1490 1491

	ctx->generation++;
1492 1493
}

J
Jiri Olsa 已提交
1494 1495 1496 1497 1498 1499 1500 1501 1502
/*
 * Initialize event state based on the perf_event_attr::disabled.
 */
static inline void perf_event__state_init(struct perf_event *event)
{
	event->state = event->attr.disabled ? PERF_EVENT_STATE_OFF :
					      PERF_EVENT_STATE_INACTIVE;
}

P
Peter Zijlstra 已提交
1503
static void __perf_event_read_size(struct perf_event *event, int nr_siblings)
1504 1505 1506 1507 1508 1509 1510 1511 1512 1513 1514 1515 1516 1517 1518
{
	int entry = sizeof(u64); /* value */
	int size = 0;
	int nr = 1;

	if (event->attr.read_format & PERF_FORMAT_TOTAL_TIME_ENABLED)
		size += sizeof(u64);

	if (event->attr.read_format & PERF_FORMAT_TOTAL_TIME_RUNNING)
		size += sizeof(u64);

	if (event->attr.read_format & PERF_FORMAT_ID)
		entry += sizeof(u64);

	if (event->attr.read_format & PERF_FORMAT_GROUP) {
P
Peter Zijlstra 已提交
1519
		nr += nr_siblings;
1520 1521 1522 1523 1524 1525 1526
		size += sizeof(u64);
	}

	size += entry * nr;
	event->read_size = size;
}

P
Peter Zijlstra 已提交
1527
static void __perf_event_header_size(struct perf_event *event, u64 sample_type)
1528 1529 1530 1531 1532 1533 1534
{
	struct perf_sample_data *data;
	u16 size = 0;

	if (sample_type & PERF_SAMPLE_IP)
		size += sizeof(data->ip);

1535 1536 1537 1538 1539 1540
	if (sample_type & PERF_SAMPLE_ADDR)
		size += sizeof(data->addr);

	if (sample_type & PERF_SAMPLE_PERIOD)
		size += sizeof(data->period);

A
Andi Kleen 已提交
1541 1542 1543
	if (sample_type & PERF_SAMPLE_WEIGHT)
		size += sizeof(data->weight);

1544 1545 1546
	if (sample_type & PERF_SAMPLE_READ)
		size += event->read_size;

1547 1548 1549
	if (sample_type & PERF_SAMPLE_DATA_SRC)
		size += sizeof(data->data_src.val);

A
Andi Kleen 已提交
1550 1551 1552
	if (sample_type & PERF_SAMPLE_TRANSACTION)
		size += sizeof(data->txn);

1553 1554 1555
	event->header_size = size;
}

P
Peter Zijlstra 已提交
1556 1557 1558 1559 1560 1561 1562 1563 1564 1565 1566
/*
 * Called at perf_event creation and when events are attached/detached from a
 * group.
 */
static void perf_event__header_size(struct perf_event *event)
{
	__perf_event_read_size(event,
			       event->group_leader->nr_siblings);
	__perf_event_header_size(event, event->attr.sample_type);
}

1567 1568 1569 1570 1571 1572
static void perf_event__id_header_size(struct perf_event *event)
{
	struct perf_sample_data *data;
	u64 sample_type = event->attr.sample_type;
	u16 size = 0;

1573 1574 1575 1576 1577 1578
	if (sample_type & PERF_SAMPLE_TID)
		size += sizeof(data->tid_entry);

	if (sample_type & PERF_SAMPLE_TIME)
		size += sizeof(data->time);

1579 1580 1581
	if (sample_type & PERF_SAMPLE_IDENTIFIER)
		size += sizeof(data->id);

1582 1583 1584 1585 1586 1587 1588 1589 1590
	if (sample_type & PERF_SAMPLE_ID)
		size += sizeof(data->id);

	if (sample_type & PERF_SAMPLE_STREAM_ID)
		size += sizeof(data->stream_id);

	if (sample_type & PERF_SAMPLE_CPU)
		size += sizeof(data->cpu_entry);

1591
	event->id_header_size = size;
1592 1593
}

P
Peter Zijlstra 已提交
1594 1595 1596 1597 1598 1599 1600 1601 1602 1603 1604 1605 1606 1607 1608 1609 1610 1611 1612 1613 1614
static bool perf_event_validate_size(struct perf_event *event)
{
	/*
	 * The values computed here will be over-written when we actually
	 * attach the event.
	 */
	__perf_event_read_size(event, event->group_leader->nr_siblings + 1);
	__perf_event_header_size(event, event->attr.sample_type & ~PERF_SAMPLE_READ);
	perf_event__id_header_size(event);

	/*
	 * Sum the lot; should not exceed the 64k limit we have on records.
	 * Conservative limit to allow for callchains and other variable fields.
	 */
	if (event->read_size + event->header_size +
	    event->id_header_size + sizeof(struct perf_event_header) >= 16*1024)
		return false;

	return true;
}

1615 1616
static void perf_group_attach(struct perf_event *event)
{
1617
	struct perf_event *group_leader = event->group_leader, *pos;
1618

P
Peter Zijlstra 已提交
1619 1620 1621 1622 1623 1624
	/*
	 * We can have double attach due to group movement in perf_event_open.
	 */
	if (event->attach_state & PERF_ATTACH_GROUP)
		return;

1625 1626 1627 1628 1629
	event->attach_state |= PERF_ATTACH_GROUP;

	if (group_leader == event)
		return;

P
Peter Zijlstra 已提交
1630 1631
	WARN_ON_ONCE(group_leader->ctx != event->ctx);

1632
	group_leader->group_caps &= event->event_caps;
1633 1634 1635

	list_add_tail(&event->group_entry, &group_leader->sibling_list);
	group_leader->nr_siblings++;
1636 1637 1638 1639 1640

	perf_event__header_size(group_leader);

	list_for_each_entry(pos, &group_leader->sibling_list, group_entry)
		perf_event__header_size(pos);
1641 1642
}

1643
/*
1644
 * Remove a event from the lists for its context.
1645
 * Must be called with ctx->mutex and ctx->lock held.
1646
 */
1647
static void
1648
list_del_event(struct perf_event *event, struct perf_event_context *ctx)
1649
{
P
Peter Zijlstra 已提交
1650 1651 1652
	WARN_ON_ONCE(event->ctx != ctx);
	lockdep_assert_held(&ctx->lock);

1653 1654 1655 1656
	/*
	 * We can have double detach due to exit/hot-unplug + close.
	 */
	if (!(event->attach_state & PERF_ATTACH_CONTEXT))
1657
		return;
1658 1659 1660

	event->attach_state &= ~PERF_ATTACH_CONTEXT;

1661
	list_update_cgroup_event(event, ctx, false);
S
Stephane Eranian 已提交
1662

1663 1664
	ctx->nr_events--;
	if (event->attr.inherit_stat)
1665
		ctx->nr_stat--;
1666

1667
	list_del_rcu(&event->event_entry);
1668

1669 1670
	if (event->group_leader == event)
		list_del_init(&event->group_entry);
P
Peter Zijlstra 已提交
1671

1672
	update_group_times(event);
1673 1674 1675 1676 1677 1678 1679 1680 1681 1682

	/*
	 * If event was in error state, then keep it
	 * that way, otherwise bogus counts will be
	 * returned on read(). The only way to get out
	 * of error state is by explicit re-enabling
	 * of the event
	 */
	if (event->state > PERF_EVENT_STATE_OFF)
		event->state = PERF_EVENT_STATE_OFF;
1683 1684

	ctx->generation++;
1685 1686
}

1687
static void perf_group_detach(struct perf_event *event)
1688 1689
{
	struct perf_event *sibling, *tmp;
1690 1691 1692 1693 1694 1695 1696 1697 1698 1699 1700 1701 1702 1703 1704 1705
	struct list_head *list = NULL;

	/*
	 * We can have double detach due to exit/hot-unplug + close.
	 */
	if (!(event->attach_state & PERF_ATTACH_GROUP))
		return;

	event->attach_state &= ~PERF_ATTACH_GROUP;

	/*
	 * If this is a sibling, remove it from its group.
	 */
	if (event->group_leader != event) {
		list_del_init(&event->group_entry);
		event->group_leader->nr_siblings--;
1706
		goto out;
1707 1708 1709 1710
	}

	if (!list_empty(&event->group_entry))
		list = &event->group_entry;
1711

1712
	/*
1713 1714
	 * If this was a group event with sibling events then
	 * upgrade the siblings to singleton events by adding them
1715
	 * to whatever list we are on.
1716
	 */
1717
	list_for_each_entry_safe(sibling, tmp, &event->sibling_list, group_entry) {
1718 1719
		if (list)
			list_move_tail(&sibling->group_entry, list);
1720
		sibling->group_leader = sibling;
1721 1722

		/* Inherit group flags from the previous leader */
1723
		sibling->group_caps = event->group_caps;
P
Peter Zijlstra 已提交
1724 1725

		WARN_ON_ONCE(sibling->ctx != event->ctx);
1726
	}
1727 1728 1729 1730 1731 1732

out:
	perf_event__header_size(event->group_leader);

	list_for_each_entry(tmp, &event->group_leader->sibling_list, group_entry)
		perf_event__header_size(tmp);
1733 1734
}

1735 1736
static bool is_orphaned_event(struct perf_event *event)
{
P
Peter Zijlstra 已提交
1737
	return event->state == PERF_EVENT_STATE_DEAD;
1738 1739
}

1740
static inline int __pmu_filter_match(struct perf_event *event)
1741 1742 1743 1744 1745
{
	struct pmu *pmu = event->pmu;
	return pmu->filter_match ? pmu->filter_match(event) : 1;
}

1746 1747 1748 1749 1750 1751 1752 1753 1754 1755 1756 1757 1758 1759 1760 1761 1762 1763 1764 1765 1766
/*
 * Check whether we should attempt to schedule an event group based on
 * PMU-specific filtering. An event group can consist of HW and SW events,
 * potentially with a SW leader, so we must check all the filters, to
 * determine whether a group is schedulable:
 */
static inline int pmu_filter_match(struct perf_event *event)
{
	struct perf_event *child;

	if (!__pmu_filter_match(event))
		return 0;

	list_for_each_entry(child, &event->sibling_list, group_entry) {
		if (!__pmu_filter_match(child))
			return 0;
	}

	return 1;
}

1767 1768 1769
static inline int
event_filter_match(struct perf_event *event)
{
1770 1771
	return (event->cpu == -1 || event->cpu == smp_processor_id()) &&
	       perf_cgroup_match(event) && pmu_filter_match(event);
1772 1773
}

1774 1775
static void
event_sched_out(struct perf_event *event,
1776
		  struct perf_cpu_context *cpuctx,
1777
		  struct perf_event_context *ctx)
1778
{
1779
	u64 tstamp = perf_event_time(event);
1780
	u64 delta;
P
Peter Zijlstra 已提交
1781 1782 1783 1784

	WARN_ON_ONCE(event->ctx != ctx);
	lockdep_assert_held(&ctx->lock);

1785 1786 1787 1788 1789 1790
	/*
	 * An event which could not be activated because of
	 * filter mismatch still needs to have its timings
	 * maintained, otherwise bogus information is return
	 * via read() for time_enabled, time_running:
	 */
1791 1792
	if (event->state == PERF_EVENT_STATE_INACTIVE &&
	    !event_filter_match(event)) {
S
Stephane Eranian 已提交
1793
		delta = tstamp - event->tstamp_stopped;
1794
		event->tstamp_running += delta;
1795
		event->tstamp_stopped = tstamp;
1796 1797
	}

1798
	if (event->state != PERF_EVENT_STATE_ACTIVE)
1799
		return;
1800

1801 1802
	perf_pmu_disable(event->pmu);

1803 1804 1805
	event->tstamp_stopped = tstamp;
	event->pmu->del(event, 0);
	event->oncpu = -1;
1806 1807 1808 1809
	event->state = PERF_EVENT_STATE_INACTIVE;
	if (event->pending_disable) {
		event->pending_disable = 0;
		event->state = PERF_EVENT_STATE_OFF;
1810
	}
1811

1812
	if (!is_software_event(event))
1813
		cpuctx->active_oncpu--;
1814 1815
	if (!--ctx->nr_active)
		perf_event_ctx_deactivate(ctx);
1816 1817
	if (event->attr.freq && event->attr.sample_freq)
		ctx->nr_freq--;
1818
	if (event->attr.exclusive || !cpuctx->active_oncpu)
1819
		cpuctx->exclusive = 0;
1820 1821

	perf_pmu_enable(event->pmu);
1822 1823
}

1824
static void
1825
group_sched_out(struct perf_event *group_event,
1826
		struct perf_cpu_context *cpuctx,
1827
		struct perf_event_context *ctx)
1828
{
1829
	struct perf_event *event;
1830
	int state = group_event->state;
1831

1832 1833
	perf_pmu_disable(ctx->pmu);

1834
	event_sched_out(group_event, cpuctx, ctx);
1835 1836 1837 1838

	/*
	 * Schedule out siblings (if any):
	 */
1839 1840
	list_for_each_entry(event, &group_event->sibling_list, group_entry)
		event_sched_out(event, cpuctx, ctx);
1841

1842 1843
	perf_pmu_enable(ctx->pmu);

1844
	if (state == PERF_EVENT_STATE_ACTIVE && group_event->attr.exclusive)
1845 1846 1847
		cpuctx->exclusive = 0;
}

1848
#define DETACH_GROUP	0x01UL
1849

T
Thomas Gleixner 已提交
1850
/*
1851
 * Cross CPU call to remove a performance event
T
Thomas Gleixner 已提交
1852
 *
1853
 * We disable the event on the hardware level first. After that we
T
Thomas Gleixner 已提交
1854 1855
 * remove it from the context list.
 */
1856 1857 1858 1859 1860
static void
__perf_remove_from_context(struct perf_event *event,
			   struct perf_cpu_context *cpuctx,
			   struct perf_event_context *ctx,
			   void *info)
T
Thomas Gleixner 已提交
1861
{
1862
	unsigned long flags = (unsigned long)info;
T
Thomas Gleixner 已提交
1863

1864
	event_sched_out(event, cpuctx, ctx);
1865
	if (flags & DETACH_GROUP)
1866
		perf_group_detach(event);
1867
	list_del_event(event, ctx);
1868 1869

	if (!ctx->nr_events && ctx->is_active) {
1870
		ctx->is_active = 0;
1871 1872 1873 1874
		if (ctx->task) {
			WARN_ON_ONCE(cpuctx->task_ctx != ctx);
			cpuctx->task_ctx = NULL;
		}
1875
	}
T
Thomas Gleixner 已提交
1876 1877 1878
}

/*
1879
 * Remove the event from a task's (or a CPU's) list of events.
T
Thomas Gleixner 已提交
1880
 *
1881 1882
 * If event->ctx is a cloned context, callers must make sure that
 * every task struct that event->ctx->task could possibly point to
1883 1884
 * remains valid.  This is OK when called from perf_release since
 * that only calls us on the top-level context, which can't be a clone.
1885
 * When called from perf_event_exit_task, it's OK because the
1886
 * context has been detached from its task.
T
Thomas Gleixner 已提交
1887
 */
1888
static void perf_remove_from_context(struct perf_event *event, unsigned long flags)
T
Thomas Gleixner 已提交
1889
{
1890
	lockdep_assert_held(&event->ctx->mutex);
T
Thomas Gleixner 已提交
1891

1892
	event_function_call(event, __perf_remove_from_context, (void *)flags);
T
Thomas Gleixner 已提交
1893 1894
}

1895
/*
1896
 * Cross CPU call to disable a performance event
1897
 */
1898 1899 1900 1901
static void __perf_event_disable(struct perf_event *event,
				 struct perf_cpu_context *cpuctx,
				 struct perf_event_context *ctx,
				 void *info)
1902
{
1903 1904
	if (event->state < PERF_EVENT_STATE_INACTIVE)
		return;
1905

1906 1907 1908 1909 1910 1911 1912 1913
	update_context_time(ctx);
	update_cgrp_time_from_event(event);
	update_group_times(event);
	if (event == event->group_leader)
		group_sched_out(event, cpuctx, ctx);
	else
		event_sched_out(event, cpuctx, ctx);
	event->state = PERF_EVENT_STATE_OFF;
1914 1915
}

1916
/*
1917
 * Disable a event.
1918
 *
1919 1920
 * If event->ctx is a cloned context, callers must make sure that
 * every task struct that event->ctx->task could possibly point to
1921
 * remains valid.  This condition is satisifed when called through
1922 1923
 * perf_event_for_each_child or perf_event_for_each because they
 * hold the top-level event's child_mutex, so any descendant that
1924 1925
 * goes to exit will block in perf_event_exit_event().
 *
1926
 * When called from perf_pending_event it's OK because event->ctx
1927
 * is the current context on this CPU and preemption is disabled,
1928
 * hence we can't get into perf_event_task_sched_out for this context.
1929
 */
P
Peter Zijlstra 已提交
1930
static void _perf_event_disable(struct perf_event *event)
1931
{
1932
	struct perf_event_context *ctx = event->ctx;
1933

1934
	raw_spin_lock_irq(&ctx->lock);
1935
	if (event->state <= PERF_EVENT_STATE_OFF) {
1936
		raw_spin_unlock_irq(&ctx->lock);
1937
		return;
1938
	}
1939
	raw_spin_unlock_irq(&ctx->lock);
1940

1941 1942 1943 1944 1945 1946
	event_function_call(event, __perf_event_disable, NULL);
}

void perf_event_disable_local(struct perf_event *event)
{
	event_function_local(event, __perf_event_disable, NULL);
1947
}
P
Peter Zijlstra 已提交
1948 1949 1950 1951 1952 1953 1954 1955 1956 1957 1958 1959 1960

/*
 * Strictly speaking kernel users cannot create groups and therefore this
 * interface does not need the perf_event_ctx_lock() magic.
 */
void perf_event_disable(struct perf_event *event)
{
	struct perf_event_context *ctx;

	ctx = perf_event_ctx_lock(event);
	_perf_event_disable(event);
	perf_event_ctx_unlock(event, ctx);
}
1961
EXPORT_SYMBOL_GPL(perf_event_disable);
1962

S
Stephane Eranian 已提交
1963 1964 1965 1966 1967 1968 1969 1970 1971 1972 1973 1974 1975 1976 1977 1978 1979 1980 1981 1982 1983 1984 1985 1986 1987 1988 1989 1990 1991 1992 1993 1994 1995 1996 1997
static void perf_set_shadow_time(struct perf_event *event,
				 struct perf_event_context *ctx,
				 u64 tstamp)
{
	/*
	 * use the correct time source for the time snapshot
	 *
	 * We could get by without this by leveraging the
	 * fact that to get to this function, the caller
	 * has most likely already called update_context_time()
	 * and update_cgrp_time_xx() and thus both timestamp
	 * are identical (or very close). Given that tstamp is,
	 * already adjusted for cgroup, we could say that:
	 *    tstamp - ctx->timestamp
	 * is equivalent to
	 *    tstamp - cgrp->timestamp.
	 *
	 * Then, in perf_output_read(), the calculation would
	 * work with no changes because:
	 * - event is guaranteed scheduled in
	 * - no scheduled out in between
	 * - thus the timestamp would be the same
	 *
	 * But this is a bit hairy.
	 *
	 * So instead, we have an explicit cgroup call to remain
	 * within the time time source all along. We believe it
	 * is cleaner and simpler to understand.
	 */
	if (is_cgroup_event(event))
		perf_cgroup_set_shadow_time(event, tstamp);
	else
		event->shadow_ctx_time = tstamp - ctx->timestamp;
}

P
Peter Zijlstra 已提交
1998 1999 2000
#define MAX_INTERRUPTS (~0ULL)

static void perf_log_throttle(struct perf_event *event, int enable);
2001
static void perf_log_itrace_start(struct perf_event *event);
P
Peter Zijlstra 已提交
2002

2003
static int
2004
event_sched_in(struct perf_event *event,
2005
		 struct perf_cpu_context *cpuctx,
2006
		 struct perf_event_context *ctx)
2007
{
2008
	u64 tstamp = perf_event_time(event);
2009
	int ret = 0;
2010

2011 2012
	lockdep_assert_held(&ctx->lock);

2013
	if (event->state <= PERF_EVENT_STATE_OFF)
2014 2015
		return 0;

2016 2017 2018 2019 2020 2021 2022
	WRITE_ONCE(event->oncpu, smp_processor_id());
	/*
	 * Order event::oncpu write to happen before the ACTIVE state
	 * is visible.
	 */
	smp_wmb();
	WRITE_ONCE(event->state, PERF_EVENT_STATE_ACTIVE);
P
Peter Zijlstra 已提交
2023 2024 2025 2026 2027 2028 2029 2030 2031 2032 2033

	/*
	 * Unthrottle events, since we scheduled we might have missed several
	 * ticks already, also for a heavily scheduling task there is little
	 * guarantee it'll get a tick in a timely manner.
	 */
	if (unlikely(event->hw.interrupts == MAX_INTERRUPTS)) {
		perf_log_throttle(event, 1);
		event->hw.interrupts = 0;
	}

2034 2035 2036 2037 2038
	/*
	 * The new state must be visible before we turn it on in the hardware:
	 */
	smp_wmb();

2039 2040
	perf_pmu_disable(event->pmu);

2041 2042
	perf_set_shadow_time(event, ctx, tstamp);

2043 2044
	perf_log_itrace_start(event);

P
Peter Zijlstra 已提交
2045
	if (event->pmu->add(event, PERF_EF_START)) {
2046 2047
		event->state = PERF_EVENT_STATE_INACTIVE;
		event->oncpu = -1;
2048 2049
		ret = -EAGAIN;
		goto out;
2050 2051
	}

2052 2053
	event->tstamp_running += tstamp - event->tstamp_stopped;

2054
	if (!is_software_event(event))
2055
		cpuctx->active_oncpu++;
2056 2057
	if (!ctx->nr_active++)
		perf_event_ctx_activate(ctx);
2058 2059
	if (event->attr.freq && event->attr.sample_freq)
		ctx->nr_freq++;
2060

2061
	if (event->attr.exclusive)
2062 2063
		cpuctx->exclusive = 1;

2064 2065 2066 2067
out:
	perf_pmu_enable(event->pmu);

	return ret;
2068 2069
}

2070
static int
2071
group_sched_in(struct perf_event *group_event,
2072
	       struct perf_cpu_context *cpuctx,
2073
	       struct perf_event_context *ctx)
2074
{
2075
	struct perf_event *event, *partial_group = NULL;
P
Peter Zijlstra 已提交
2076
	struct pmu *pmu = ctx->pmu;
2077 2078
	u64 now = ctx->time;
	bool simulate = false;
2079

2080
	if (group_event->state == PERF_EVENT_STATE_OFF)
2081 2082
		return 0;

2083
	pmu->start_txn(pmu, PERF_PMU_TXN_ADD);
2084

2085
	if (event_sched_in(group_event, cpuctx, ctx)) {
P
Peter Zijlstra 已提交
2086
		pmu->cancel_txn(pmu);
2087
		perf_mux_hrtimer_restart(cpuctx);
2088
		return -EAGAIN;
2089
	}
2090 2091 2092 2093

	/*
	 * Schedule in siblings as one group (if any):
	 */
2094
	list_for_each_entry(event, &group_event->sibling_list, group_entry) {
2095
		if (event_sched_in(event, cpuctx, ctx)) {
2096
			partial_group = event;
2097 2098 2099 2100
			goto group_error;
		}
	}

2101
	if (!pmu->commit_txn(pmu))
2102
		return 0;
2103

2104 2105 2106 2107
group_error:
	/*
	 * Groups can be scheduled in as one unit only, so undo any
	 * partial group before returning:
2108 2109 2110 2111 2112 2113 2114 2115 2116 2117
	 * The events up to the failed event are scheduled out normally,
	 * tstamp_stopped will be updated.
	 *
	 * The failed events and the remaining siblings need to have
	 * their timings updated as if they had gone thru event_sched_in()
	 * and event_sched_out(). This is required to get consistent timings
	 * across the group. This also takes care of the case where the group
	 * could never be scheduled by ensuring tstamp_stopped is set to mark
	 * the time the event was actually stopped, such that time delta
	 * calculation in update_event_times() is correct.
2118
	 */
2119 2120
	list_for_each_entry(event, &group_event->sibling_list, group_entry) {
		if (event == partial_group)
2121 2122 2123 2124 2125 2126 2127 2128
			simulate = true;

		if (simulate) {
			event->tstamp_running += now - event->tstamp_stopped;
			event->tstamp_stopped = now;
		} else {
			event_sched_out(event, cpuctx, ctx);
		}
2129
	}
2130
	event_sched_out(group_event, cpuctx, ctx);
2131

P
Peter Zijlstra 已提交
2132
	pmu->cancel_txn(pmu);
2133

2134
	perf_mux_hrtimer_restart(cpuctx);
2135

2136 2137 2138
	return -EAGAIN;
}

2139
/*
2140
 * Work out whether we can put this event group on the CPU now.
2141
 */
2142
static int group_can_go_on(struct perf_event *event,
2143 2144 2145 2146
			   struct perf_cpu_context *cpuctx,
			   int can_add_hw)
{
	/*
2147
	 * Groups consisting entirely of software events can always go on.
2148
	 */
2149
	if (event->group_caps & PERF_EV_CAP_SOFTWARE)
2150 2151 2152
		return 1;
	/*
	 * If an exclusive group is already on, no other hardware
2153
	 * events can go on.
2154 2155 2156 2157 2158
	 */
	if (cpuctx->exclusive)
		return 0;
	/*
	 * If this group is exclusive and there are already
2159
	 * events on the CPU, it can't go on.
2160
	 */
2161
	if (event->attr.exclusive && cpuctx->active_oncpu)
2162 2163 2164 2165 2166 2167 2168 2169
		return 0;
	/*
	 * Otherwise, try to add it if all previous groups were able
	 * to go on.
	 */
	return can_add_hw;
}

2170 2171
static void add_event_to_ctx(struct perf_event *event,
			       struct perf_event_context *ctx)
2172
{
2173 2174
	u64 tstamp = perf_event_time(event);

2175
	list_add_event(event, ctx);
2176
	perf_group_attach(event);
2177 2178 2179
	event->tstamp_enabled = tstamp;
	event->tstamp_running = tstamp;
	event->tstamp_stopped = tstamp;
2180 2181
}

2182 2183 2184
static void ctx_sched_out(struct perf_event_context *ctx,
			  struct perf_cpu_context *cpuctx,
			  enum event_type_t event_type);
2185 2186 2187 2188 2189
static void
ctx_sched_in(struct perf_event_context *ctx,
	     struct perf_cpu_context *cpuctx,
	     enum event_type_t event_type,
	     struct task_struct *task);
2190

2191 2192 2193 2194 2195 2196 2197 2198 2199 2200 2201 2202
static void task_ctx_sched_out(struct perf_cpu_context *cpuctx,
			       struct perf_event_context *ctx)
{
	if (!cpuctx->task_ctx)
		return;

	if (WARN_ON_ONCE(ctx != cpuctx->task_ctx))
		return;

	ctx_sched_out(ctx, cpuctx, EVENT_ALL);
}

2203 2204 2205 2206 2207 2208 2209 2210 2211 2212 2213 2214
static void perf_event_sched_in(struct perf_cpu_context *cpuctx,
				struct perf_event_context *ctx,
				struct task_struct *task)
{
	cpu_ctx_sched_in(cpuctx, EVENT_PINNED, task);
	if (ctx)
		ctx_sched_in(ctx, cpuctx, EVENT_PINNED, task);
	cpu_ctx_sched_in(cpuctx, EVENT_FLEXIBLE, task);
	if (ctx)
		ctx_sched_in(ctx, cpuctx, EVENT_FLEXIBLE, task);
}

2215 2216
static void ctx_resched(struct perf_cpu_context *cpuctx,
			struct perf_event_context *task_ctx)
2217
{
2218 2219 2220 2221 2222 2223
	perf_pmu_disable(cpuctx->ctx.pmu);
	if (task_ctx)
		task_ctx_sched_out(cpuctx, task_ctx);
	cpu_ctx_sched_out(cpuctx, EVENT_ALL);
	perf_event_sched_in(cpuctx, task_ctx, current);
	perf_pmu_enable(cpuctx->ctx.pmu);
2224 2225
}

T
Thomas Gleixner 已提交
2226
/*
2227
 * Cross CPU call to install and enable a performance event
2228
 *
2229 2230
 * Very similar to remote_function() + event_function() but cannot assume that
 * things like ctx->is_active and cpuctx->task_ctx are set.
T
Thomas Gleixner 已提交
2231
 */
2232
static int  __perf_install_in_context(void *info)
T
Thomas Gleixner 已提交
2233
{
2234 2235
	struct perf_event *event = info;
	struct perf_event_context *ctx = event->ctx;
P
Peter Zijlstra 已提交
2236
	struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
2237
	struct perf_event_context *task_ctx = cpuctx->task_ctx;
2238 2239
	bool activate = true;
	int ret = 0;
T
Thomas Gleixner 已提交
2240

2241
	raw_spin_lock(&cpuctx->ctx.lock);
2242
	if (ctx->task) {
2243 2244
		raw_spin_lock(&ctx->lock);
		task_ctx = ctx;
2245 2246 2247 2248

		/* If we're on the wrong CPU, try again */
		if (task_cpu(ctx->task) != smp_processor_id()) {
			ret = -ESRCH;
2249
			goto unlock;
2250
		}
2251

2252
		/*
2253 2254 2255
		 * If we're on the right CPU, see if the task we target is
		 * current, if not we don't have to activate the ctx, a future
		 * context switch will do that for us.
2256
		 */
2257 2258 2259 2260 2261
		if (ctx->task != current)
			activate = false;
		else
			WARN_ON_ONCE(cpuctx->task_ctx && cpuctx->task_ctx != ctx);

2262 2263
	} else if (task_ctx) {
		raw_spin_lock(&task_ctx->lock);
2264
	}
2265

2266 2267 2268 2269 2270 2271 2272 2273
	if (activate) {
		ctx_sched_out(ctx, cpuctx, EVENT_TIME);
		add_event_to_ctx(event, ctx);
		ctx_resched(cpuctx, task_ctx);
	} else {
		add_event_to_ctx(event, ctx);
	}

2274
unlock:
2275
	perf_ctx_unlock(cpuctx, task_ctx);
2276

2277
	return ret;
T
Thomas Gleixner 已提交
2278 2279 2280
}

/*
2281 2282 2283
 * Attach a performance event to a context.
 *
 * Very similar to event_function_call, see comment there.
T
Thomas Gleixner 已提交
2284 2285
 */
static void
2286 2287
perf_install_in_context(struct perf_event_context *ctx,
			struct perf_event *event,
T
Thomas Gleixner 已提交
2288 2289
			int cpu)
{
2290
	struct task_struct *task = READ_ONCE(ctx->task);
2291

2292 2293
	lockdep_assert_held(&ctx->mutex);

2294 2295
	if (event->cpu != -1)
		event->cpu = cpu;
2296

2297 2298 2299 2300 2301 2302
	/*
	 * Ensures that if we can observe event->ctx, both the event and ctx
	 * will be 'complete'. See perf_iterate_sb_cpu().
	 */
	smp_store_release(&event->ctx, ctx);

2303 2304 2305 2306 2307 2308 2309 2310 2311 2312 2313
	if (!task) {
		cpu_function_call(cpu, __perf_install_in_context, event);
		return;
	}

	/*
	 * Should not happen, we validate the ctx is still alive before calling.
	 */
	if (WARN_ON_ONCE(task == TASK_TOMBSTONE))
		return;

2314 2315 2316 2317
	/*
	 * Installing events is tricky because we cannot rely on ctx->is_active
	 * to be set in case this is the nr_events 0 -> 1 transition.
	 */
2318
again:
2319
	/*
2320 2321
	 * Cannot use task_function_call() because we need to run on the task's
	 * CPU regardless of whether its current or not.
2322
	 */
2323 2324 2325 2326 2327
	if (!cpu_function_call(task_cpu(task), __perf_install_in_context, event))
		return;

	raw_spin_lock_irq(&ctx->lock);
	task = ctx->task;
2328
	if (WARN_ON_ONCE(task == TASK_TOMBSTONE)) {
2329 2330 2331 2332 2333
		/*
		 * Cannot happen because we already checked above (which also
		 * cannot happen), and we hold ctx->mutex, which serializes us
		 * against perf_event_exit_task_context().
		 */
2334 2335 2336
		raw_spin_unlock_irq(&ctx->lock);
		return;
	}
2337 2338
	raw_spin_unlock_irq(&ctx->lock);
	/*
2339 2340
	 * Since !ctx->is_active doesn't mean anything, we must IPI
	 * unconditionally.
2341
	 */
2342
	goto again;
T
Thomas Gleixner 已提交
2343 2344
}

2345
/*
2346
 * Put a event into inactive state and update time fields.
2347 2348 2349 2350 2351 2352
 * Enabling the leader of a group effectively enables all
 * the group members that aren't explicitly disabled, so we
 * have to update their ->tstamp_enabled also.
 * Note: this works for group members as well as group leaders
 * since the non-leader members' sibling_lists will be empty.
 */
2353
static void __perf_event_mark_enabled(struct perf_event *event)
2354
{
2355
	struct perf_event *sub;
2356
	u64 tstamp = perf_event_time(event);
2357

2358
	event->state = PERF_EVENT_STATE_INACTIVE;
2359
	event->tstamp_enabled = tstamp - event->total_time_enabled;
P
Peter Zijlstra 已提交
2360
	list_for_each_entry(sub, &event->sibling_list, group_entry) {
2361 2362
		if (sub->state >= PERF_EVENT_STATE_INACTIVE)
			sub->tstamp_enabled = tstamp - sub->total_time_enabled;
P
Peter Zijlstra 已提交
2363
	}
2364 2365
}

2366
/*
2367
 * Cross CPU call to enable a performance event
2368
 */
2369 2370 2371 2372
static void __perf_event_enable(struct perf_event *event,
				struct perf_cpu_context *cpuctx,
				struct perf_event_context *ctx,
				void *info)
2373
{
2374
	struct perf_event *leader = event->group_leader;
2375
	struct perf_event_context *task_ctx;
2376

P
Peter Zijlstra 已提交
2377 2378
	if (event->state >= PERF_EVENT_STATE_INACTIVE ||
	    event->state <= PERF_EVENT_STATE_ERROR)
2379
		return;
2380

2381 2382 2383
	if (ctx->is_active)
		ctx_sched_out(ctx, cpuctx, EVENT_TIME);

2384
	__perf_event_mark_enabled(event);
2385

2386 2387 2388
	if (!ctx->is_active)
		return;

S
Stephane Eranian 已提交
2389
	if (!event_filter_match(event)) {
2390
		if (is_cgroup_event(event))
S
Stephane Eranian 已提交
2391
			perf_cgroup_defer_enabled(event);
2392
		ctx_sched_in(ctx, cpuctx, EVENT_TIME, current);
2393
		return;
S
Stephane Eranian 已提交
2394
	}
2395

2396
	/*
2397
	 * If the event is in a group and isn't the group leader,
2398
	 * then don't put it on unless the group is on.
2399
	 */
2400 2401
	if (leader != event && leader->state != PERF_EVENT_STATE_ACTIVE) {
		ctx_sched_in(ctx, cpuctx, EVENT_TIME, current);
2402
		return;
2403
	}
2404

2405 2406 2407
	task_ctx = cpuctx->task_ctx;
	if (ctx->task)
		WARN_ON_ONCE(task_ctx != ctx);
2408

2409
	ctx_resched(cpuctx, task_ctx);
2410 2411
}

2412
/*
2413
 * Enable a event.
2414
 *
2415 2416
 * If event->ctx is a cloned context, callers must make sure that
 * every task struct that event->ctx->task could possibly point to
2417
 * remains valid.  This condition is satisfied when called through
2418 2419
 * perf_event_for_each_child or perf_event_for_each as described
 * for perf_event_disable.
2420
 */
P
Peter Zijlstra 已提交
2421
static void _perf_event_enable(struct perf_event *event)
2422
{
2423
	struct perf_event_context *ctx = event->ctx;
2424

2425
	raw_spin_lock_irq(&ctx->lock);
P
Peter Zijlstra 已提交
2426 2427
	if (event->state >= PERF_EVENT_STATE_INACTIVE ||
	    event->state <  PERF_EVENT_STATE_ERROR) {
2428
		raw_spin_unlock_irq(&ctx->lock);
2429 2430 2431 2432
		return;
	}

	/*
2433
	 * If the event is in error state, clear that first.
2434 2435 2436 2437
	 *
	 * That way, if we see the event in error state below, we know that it
	 * has gone back into error state, as distinct from the task having
	 * been scheduled away before the cross-call arrived.
2438
	 */
2439 2440
	if (event->state == PERF_EVENT_STATE_ERROR)
		event->state = PERF_EVENT_STATE_OFF;
2441
	raw_spin_unlock_irq(&ctx->lock);
2442

2443
	event_function_call(event, __perf_event_enable, NULL);
2444
}
P
Peter Zijlstra 已提交
2445 2446 2447 2448 2449 2450 2451 2452 2453 2454 2455 2456

/*
 * See perf_event_disable();
 */
void perf_event_enable(struct perf_event *event)
{
	struct perf_event_context *ctx;

	ctx = perf_event_ctx_lock(event);
	_perf_event_enable(event);
	perf_event_ctx_unlock(event, ctx);
}
2457
EXPORT_SYMBOL_GPL(perf_event_enable);
2458

2459 2460 2461 2462 2463
struct stop_event_data {
	struct perf_event	*event;
	unsigned int		restart;
};

2464 2465
static int __perf_event_stop(void *info)
{
2466 2467
	struct stop_event_data *sd = info;
	struct perf_event *event = sd->event;
2468

2469
	/* if it's already INACTIVE, do nothing */
2470 2471 2472 2473 2474 2475 2476 2477 2478 2479 2480 2481 2482 2483 2484
	if (READ_ONCE(event->state) != PERF_EVENT_STATE_ACTIVE)
		return 0;

	/* matches smp_wmb() in event_sched_in() */
	smp_rmb();

	/*
	 * There is a window with interrupts enabled before we get here,
	 * so we need to check again lest we try to stop another CPU's event.
	 */
	if (READ_ONCE(event->oncpu) != smp_processor_id())
		return -EAGAIN;

	event->pmu->stop(event, PERF_EF_UPDATE);

2485 2486 2487 2488 2489 2490 2491 2492 2493 2494 2495 2496
	/*
	 * May race with the actual stop (through perf_pmu_output_stop()),
	 * but it is only used for events with AUX ring buffer, and such
	 * events will refuse to restart because of rb::aux_mmap_count==0,
	 * see comments in perf_aux_output_begin().
	 *
	 * Since this is happening on a event-local CPU, no trace is lost
	 * while restarting.
	 */
	if (sd->restart)
		event->pmu->start(event, PERF_EF_START);

2497 2498 2499
	return 0;
}

2500 2501 2502 2503 2504 2505 2506 2507 2508 2509 2510 2511 2512 2513 2514 2515 2516 2517 2518 2519 2520 2521 2522 2523 2524 2525 2526 2527 2528 2529 2530 2531 2532 2533 2534 2535 2536 2537 2538 2539 2540 2541 2542 2543 2544 2545 2546 2547 2548 2549 2550 2551 2552 2553 2554 2555 2556 2557 2558 2559 2560 2561 2562 2563 2564
static int perf_event_restart(struct perf_event *event)
{
	struct stop_event_data sd = {
		.event		= event,
		.restart	= 1,
	};
	int ret = 0;

	do {
		if (READ_ONCE(event->state) != PERF_EVENT_STATE_ACTIVE)
			return 0;

		/* matches smp_wmb() in event_sched_in() */
		smp_rmb();

		/*
		 * We only want to restart ACTIVE events, so if the event goes
		 * inactive here (event->oncpu==-1), there's nothing more to do;
		 * fall through with ret==-ENXIO.
		 */
		ret = cpu_function_call(READ_ONCE(event->oncpu),
					__perf_event_stop, &sd);
	} while (ret == -EAGAIN);

	return ret;
}

/*
 * In order to contain the amount of racy and tricky in the address filter
 * configuration management, it is a two part process:
 *
 * (p1) when userspace mappings change as a result of (1) or (2) or (3) below,
 *      we update the addresses of corresponding vmas in
 *	event::addr_filters_offs array and bump the event::addr_filters_gen;
 * (p2) when an event is scheduled in (pmu::add), it calls
 *      perf_event_addr_filters_sync() which calls pmu::addr_filters_sync()
 *      if the generation has changed since the previous call.
 *
 * If (p1) happens while the event is active, we restart it to force (p2).
 *
 * (1) perf_addr_filters_apply(): adjusting filters' offsets based on
 *     pre-existing mappings, called once when new filters arrive via SET_FILTER
 *     ioctl;
 * (2) perf_addr_filters_adjust(): adjusting filters' offsets based on newly
 *     registered mapping, called for every new mmap(), with mm::mmap_sem down
 *     for reading;
 * (3) perf_event_addr_filters_exec(): clearing filters' offsets in the process
 *     of exec.
 */
void perf_event_addr_filters_sync(struct perf_event *event)
{
	struct perf_addr_filters_head *ifh = perf_event_addr_filters(event);

	if (!has_addr_filter(event))
		return;

	raw_spin_lock(&ifh->lock);
	if (event->addr_filters_gen != event->hw.addr_filters_gen) {
		event->pmu->addr_filters_sync(event);
		event->hw.addr_filters_gen = event->addr_filters_gen;
	}
	raw_spin_unlock(&ifh->lock);
}
EXPORT_SYMBOL_GPL(perf_event_addr_filters_sync);

P
Peter Zijlstra 已提交
2565
static int _perf_event_refresh(struct perf_event *event, int refresh)
2566
{
2567
	/*
2568
	 * not supported on inherited events
2569
	 */
2570
	if (event->attr.inherit || !is_sampling_event(event))
2571 2572
		return -EINVAL;

2573
	atomic_add(refresh, &event->event_limit);
P
Peter Zijlstra 已提交
2574
	_perf_event_enable(event);
2575 2576

	return 0;
2577
}
P
Peter Zijlstra 已提交
2578 2579 2580 2581 2582 2583 2584 2585 2586 2587 2588 2589 2590 2591 2592

/*
 * See perf_event_disable()
 */
int perf_event_refresh(struct perf_event *event, int refresh)
{
	struct perf_event_context *ctx;
	int ret;

	ctx = perf_event_ctx_lock(event);
	ret = _perf_event_refresh(event, refresh);
	perf_event_ctx_unlock(event, ctx);

	return ret;
}
2593
EXPORT_SYMBOL_GPL(perf_event_refresh);
2594

2595 2596 2597
static void ctx_sched_out(struct perf_event_context *ctx,
			  struct perf_cpu_context *cpuctx,
			  enum event_type_t event_type)
2598
{
2599
	int is_active = ctx->is_active;
P
Peter Zijlstra 已提交
2600
	struct perf_event *event;
2601

P
Peter Zijlstra 已提交
2602
	lockdep_assert_held(&ctx->lock);
2603

2604 2605 2606 2607 2608 2609 2610
	if (likely(!ctx->nr_events)) {
		/*
		 * See __perf_remove_from_context().
		 */
		WARN_ON_ONCE(ctx->is_active);
		if (ctx->task)
			WARN_ON_ONCE(cpuctx->task_ctx);
2611
		return;
2612 2613
	}

2614
	ctx->is_active &= ~event_type;
2615 2616 2617
	if (!(ctx->is_active & EVENT_ALL))
		ctx->is_active = 0;

2618 2619 2620 2621 2622
	if (ctx->task) {
		WARN_ON_ONCE(cpuctx->task_ctx != ctx);
		if (!ctx->is_active)
			cpuctx->task_ctx = NULL;
	}
2623

2624 2625 2626 2627 2628 2629 2630 2631 2632 2633
	/*
	 * Always update time if it was set; not only when it changes.
	 * Otherwise we can 'forget' to update time for any but the last
	 * context we sched out. For example:
	 *
	 *   ctx_sched_out(.event_type = EVENT_FLEXIBLE)
	 *   ctx_sched_out(.event_type = EVENT_PINNED)
	 *
	 * would only update time for the pinned events.
	 */
2634 2635 2636 2637 2638 2639
	if (is_active & EVENT_TIME) {
		/* update (and stop) ctx time */
		update_context_time(ctx);
		update_cgrp_time_from_cpuctx(cpuctx);
	}

2640 2641
	is_active ^= ctx->is_active; /* changed bits */

2642
	if (!ctx->nr_active || !(is_active & EVENT_ALL))
2643
		return;
2644

P
Peter Zijlstra 已提交
2645
	perf_pmu_disable(ctx->pmu);
2646
	if (is_active & EVENT_PINNED) {
2647 2648
		list_for_each_entry(event, &ctx->pinned_groups, group_entry)
			group_sched_out(event, cpuctx, ctx);
P
Peter Zijlstra 已提交
2649
	}
2650

2651
	if (is_active & EVENT_FLEXIBLE) {
2652
		list_for_each_entry(event, &ctx->flexible_groups, group_entry)
2653
			group_sched_out(event, cpuctx, ctx);
P
Peter Zijlstra 已提交
2654
	}
P
Peter Zijlstra 已提交
2655
	perf_pmu_enable(ctx->pmu);
2656 2657
}

2658
/*
2659 2660 2661 2662 2663 2664
 * Test whether two contexts are equivalent, i.e. whether they have both been
 * cloned from the same version of the same context.
 *
 * Equivalence is measured using a generation number in the context that is
 * incremented on each modification to it; see unclone_ctx(), list_add_event()
 * and list_del_event().
2665
 */
2666 2667
static int context_equiv(struct perf_event_context *ctx1,
			 struct perf_event_context *ctx2)
2668
{
2669 2670 2671
	lockdep_assert_held(&ctx1->lock);
	lockdep_assert_held(&ctx2->lock);

2672 2673 2674 2675 2676 2677 2678 2679 2680 2681 2682 2683 2684 2685 2686 2687 2688 2689 2690 2691 2692 2693
	/* Pinning disables the swap optimization */
	if (ctx1->pin_count || ctx2->pin_count)
		return 0;

	/* If ctx1 is the parent of ctx2 */
	if (ctx1 == ctx2->parent_ctx && ctx1->generation == ctx2->parent_gen)
		return 1;

	/* If ctx2 is the parent of ctx1 */
	if (ctx1->parent_ctx == ctx2 && ctx1->parent_gen == ctx2->generation)
		return 1;

	/*
	 * If ctx1 and ctx2 have the same parent; we flatten the parent
	 * hierarchy, see perf_event_init_context().
	 */
	if (ctx1->parent_ctx && ctx1->parent_ctx == ctx2->parent_ctx &&
			ctx1->parent_gen == ctx2->parent_gen)
		return 1;

	/* Unmatched */
	return 0;
2694 2695
}

2696 2697
static void __perf_event_sync_stat(struct perf_event *event,
				     struct perf_event *next_event)
2698 2699 2700
{
	u64 value;

2701
	if (!event->attr.inherit_stat)
2702 2703 2704
		return;

	/*
2705
	 * Update the event value, we cannot use perf_event_read()
2706 2707
	 * because we're in the middle of a context switch and have IRQs
	 * disabled, which upsets smp_call_function_single(), however
2708
	 * we know the event must be on the current CPU, therefore we
2709 2710
	 * don't need to use it.
	 */
2711 2712
	switch (event->state) {
	case PERF_EVENT_STATE_ACTIVE:
2713 2714
		event->pmu->read(event);
		/* fall-through */
2715

2716 2717
	case PERF_EVENT_STATE_INACTIVE:
		update_event_times(event);
2718 2719 2720 2721 2722 2723 2724
		break;

	default:
		break;
	}

	/*
2725
	 * In order to keep per-task stats reliable we need to flip the event
2726 2727
	 * values when we flip the contexts.
	 */
2728 2729 2730
	value = local64_read(&next_event->count);
	value = local64_xchg(&event->count, value);
	local64_set(&next_event->count, value);
2731

2732 2733
	swap(event->total_time_enabled, next_event->total_time_enabled);
	swap(event->total_time_running, next_event->total_time_running);
2734

2735
	/*
2736
	 * Since we swizzled the values, update the user visible data too.
2737
	 */
2738 2739
	perf_event_update_userpage(event);
	perf_event_update_userpage(next_event);
2740 2741
}

2742 2743
static void perf_event_sync_stat(struct perf_event_context *ctx,
				   struct perf_event_context *next_ctx)
2744
{
2745
	struct perf_event *event, *next_event;
2746 2747 2748 2749

	if (!ctx->nr_stat)
		return;

2750 2751
	update_context_time(ctx);

2752 2753
	event = list_first_entry(&ctx->event_list,
				   struct perf_event, event_entry);
2754

2755 2756
	next_event = list_first_entry(&next_ctx->event_list,
					struct perf_event, event_entry);
2757

2758 2759
	while (&event->event_entry != &ctx->event_list &&
	       &next_event->event_entry != &next_ctx->event_list) {
2760

2761
		__perf_event_sync_stat(event, next_event);
2762

2763 2764
		event = list_next_entry(event, event_entry);
		next_event = list_next_entry(next_event, event_entry);
2765 2766 2767
	}
}

2768 2769
static void perf_event_context_sched_out(struct task_struct *task, int ctxn,
					 struct task_struct *next)
T
Thomas Gleixner 已提交
2770
{
P
Peter Zijlstra 已提交
2771
	struct perf_event_context *ctx = task->perf_event_ctxp[ctxn];
2772
	struct perf_event_context *next_ctx;
2773
	struct perf_event_context *parent, *next_parent;
P
Peter Zijlstra 已提交
2774
	struct perf_cpu_context *cpuctx;
2775
	int do_switch = 1;
T
Thomas Gleixner 已提交
2776

P
Peter Zijlstra 已提交
2777 2778
	if (likely(!ctx))
		return;
2779

P
Peter Zijlstra 已提交
2780 2781
	cpuctx = __get_cpu_context(ctx);
	if (!cpuctx->task_ctx)
T
Thomas Gleixner 已提交
2782 2783
		return;

2784
	rcu_read_lock();
P
Peter Zijlstra 已提交
2785
	next_ctx = next->perf_event_ctxp[ctxn];
2786 2787 2788 2789 2790 2791 2792
	if (!next_ctx)
		goto unlock;

	parent = rcu_dereference(ctx->parent_ctx);
	next_parent = rcu_dereference(next_ctx->parent_ctx);

	/* If neither context have a parent context; they cannot be clones. */
2793
	if (!parent && !next_parent)
2794 2795 2796
		goto unlock;

	if (next_parent == ctx || next_ctx == parent || next_parent == parent) {
2797 2798 2799 2800 2801 2802 2803 2804 2805
		/*
		 * Looks like the two contexts are clones, so we might be
		 * able to optimize the context switch.  We lock both
		 * contexts and check that they are clones under the
		 * lock (including re-checking that neither has been
		 * uncloned in the meantime).  It doesn't matter which
		 * order we take the locks because no other cpu could
		 * be trying to lock both of these tasks.
		 */
2806 2807
		raw_spin_lock(&ctx->lock);
		raw_spin_lock_nested(&next_ctx->lock, SINGLE_DEPTH_NESTING);
2808
		if (context_equiv(ctx, next_ctx)) {
2809 2810
			WRITE_ONCE(ctx->task, next);
			WRITE_ONCE(next_ctx->task, task);
2811 2812 2813

			swap(ctx->task_ctx_data, next_ctx->task_ctx_data);

2814 2815 2816 2817 2818 2819 2820 2821 2822 2823
			/*
			 * RCU_INIT_POINTER here is safe because we've not
			 * modified the ctx and the above modification of
			 * ctx->task and ctx->task_ctx_data are immaterial
			 * since those values are always verified under
			 * ctx->lock which we're now holding.
			 */
			RCU_INIT_POINTER(task->perf_event_ctxp[ctxn], next_ctx);
			RCU_INIT_POINTER(next->perf_event_ctxp[ctxn], ctx);

2824
			do_switch = 0;
2825

2826
			perf_event_sync_stat(ctx, next_ctx);
2827
		}
2828 2829
		raw_spin_unlock(&next_ctx->lock);
		raw_spin_unlock(&ctx->lock);
2830
	}
2831
unlock:
2832
	rcu_read_unlock();
2833

2834
	if (do_switch) {
2835
		raw_spin_lock(&ctx->lock);
P
Peter Zijlstra 已提交
2836
		task_ctx_sched_out(cpuctx, ctx);
2837
		raw_spin_unlock(&ctx->lock);
2838
	}
T
Thomas Gleixner 已提交
2839 2840
}

2841 2842
static DEFINE_PER_CPU(struct list_head, sched_cb_list);

2843 2844
void perf_sched_cb_dec(struct pmu *pmu)
{
2845 2846
	struct perf_cpu_context *cpuctx = this_cpu_ptr(pmu->pmu_cpu_context);

2847
	this_cpu_dec(perf_sched_cb_usages);
2848 2849 2850

	if (!--cpuctx->sched_cb_usage)
		list_del(&cpuctx->sched_cb_entry);
2851 2852
}

2853

2854 2855
void perf_sched_cb_inc(struct pmu *pmu)
{
2856 2857 2858 2859 2860
	struct perf_cpu_context *cpuctx = this_cpu_ptr(pmu->pmu_cpu_context);

	if (!cpuctx->sched_cb_usage++)
		list_add(&cpuctx->sched_cb_entry, this_cpu_ptr(&sched_cb_list));

2861 2862 2863 2864 2865 2866
	this_cpu_inc(perf_sched_cb_usages);
}

/*
 * This function provides the context switch callback to the lower code
 * layer. It is invoked ONLY when the context switch callback is enabled.
2867 2868 2869 2870
 *
 * This callback is relevant even to per-cpu events; for example multi event
 * PEBS requires this to provide PID/TID information. This requires we flush
 * all queued PEBS records before we context switch to a new task.
2871 2872 2873 2874 2875 2876 2877 2878 2879 2880 2881
 */
static void perf_pmu_sched_task(struct task_struct *prev,
				struct task_struct *next,
				bool sched_in)
{
	struct perf_cpu_context *cpuctx;
	struct pmu *pmu;

	if (prev == next)
		return;

2882 2883
	list_for_each_entry(cpuctx, this_cpu_ptr(&sched_cb_list), sched_cb_entry) {
		pmu = cpuctx->unique_pmu; /* software PMUs will not have sched_task */
2884

2885 2886
		if (WARN_ON_ONCE(!pmu->sched_task))
			continue;
2887

2888 2889
		perf_ctx_lock(cpuctx, cpuctx->task_ctx);
		perf_pmu_disable(pmu);
2890

2891
		pmu->sched_task(cpuctx->task_ctx, sched_in);
2892

2893 2894
		perf_pmu_enable(pmu);
		perf_ctx_unlock(cpuctx, cpuctx->task_ctx);
2895 2896 2897
	}
}

2898 2899 2900
static void perf_event_switch(struct task_struct *task,
			      struct task_struct *next_prev, bool sched_in);

P
Peter Zijlstra 已提交
2901 2902 2903 2904 2905 2906 2907 2908 2909 2910 2911 2912 2913 2914
#define for_each_task_context_nr(ctxn)					\
	for ((ctxn) = 0; (ctxn) < perf_nr_task_contexts; (ctxn)++)

/*
 * Called from scheduler to remove the events of the current task,
 * with interrupts disabled.
 *
 * We stop each event and update the event value in event->count.
 *
 * This does not protect us against NMI, but disable()
 * sets the disabled bit in the control field of event _before_
 * accessing the event control register. If a NMI hits, then it will
 * not restart the event.
 */
2915 2916
void __perf_event_task_sched_out(struct task_struct *task,
				 struct task_struct *next)
P
Peter Zijlstra 已提交
2917 2918 2919
{
	int ctxn;

2920 2921 2922
	if (__this_cpu_read(perf_sched_cb_usages))
		perf_pmu_sched_task(task, next, false);

2923 2924 2925
	if (atomic_read(&nr_switch_events))
		perf_event_switch(task, next, false);

P
Peter Zijlstra 已提交
2926 2927
	for_each_task_context_nr(ctxn)
		perf_event_context_sched_out(task, ctxn, next);
S
Stephane Eranian 已提交
2928 2929 2930 2931 2932 2933

	/*
	 * if cgroup events exist on this CPU, then we need
	 * to check if we have to switch out PMU state.
	 * cgroup event are system-wide mode only
	 */
2934
	if (atomic_read(this_cpu_ptr(&perf_cgroup_events)))
2935
		perf_cgroup_sched_out(task, next);
P
Peter Zijlstra 已提交
2936 2937
}

2938 2939 2940 2941 2942 2943 2944
/*
 * Called with IRQs disabled
 */
static void cpu_ctx_sched_out(struct perf_cpu_context *cpuctx,
			      enum event_type_t event_type)
{
	ctx_sched_out(&cpuctx->ctx, cpuctx, event_type);
2945 2946
}

2947
static void
2948
ctx_pinned_sched_in(struct perf_event_context *ctx,
2949
		    struct perf_cpu_context *cpuctx)
T
Thomas Gleixner 已提交
2950
{
2951
	struct perf_event *event;
T
Thomas Gleixner 已提交
2952

2953 2954
	list_for_each_entry(event, &ctx->pinned_groups, group_entry) {
		if (event->state <= PERF_EVENT_STATE_OFF)
2955
			continue;
2956
		if (!event_filter_match(event))
2957 2958
			continue;

S
Stephane Eranian 已提交
2959 2960 2961 2962
		/* may need to reset tstamp_enabled */
		if (is_cgroup_event(event))
			perf_cgroup_mark_enabled(event, ctx);

2963
		if (group_can_go_on(event, cpuctx, 1))
2964
			group_sched_in(event, cpuctx, ctx);
2965 2966 2967 2968 2969

		/*
		 * If this pinned group hasn't been scheduled,
		 * put it in error state.
		 */
2970 2971 2972
		if (event->state == PERF_EVENT_STATE_INACTIVE) {
			update_group_times(event);
			event->state = PERF_EVENT_STATE_ERROR;
2973
		}
2974
	}
2975 2976 2977 2978
}

static void
ctx_flexible_sched_in(struct perf_event_context *ctx,
2979
		      struct perf_cpu_context *cpuctx)
2980 2981 2982
{
	struct perf_event *event;
	int can_add_hw = 1;
2983

2984 2985 2986
	list_for_each_entry(event, &ctx->flexible_groups, group_entry) {
		/* Ignore events in OFF or ERROR state */
		if (event->state <= PERF_EVENT_STATE_OFF)
2987
			continue;
2988 2989
		/*
		 * Listen to the 'cpu' scheduling filter constraint
2990
		 * of events:
2991
		 */
2992
		if (!event_filter_match(event))
T
Thomas Gleixner 已提交
2993 2994
			continue;

S
Stephane Eranian 已提交
2995 2996 2997 2998
		/* may need to reset tstamp_enabled */
		if (is_cgroup_event(event))
			perf_cgroup_mark_enabled(event, ctx);

P
Peter Zijlstra 已提交
2999
		if (group_can_go_on(event, cpuctx, can_add_hw)) {
3000
			if (group_sched_in(event, cpuctx, ctx))
3001
				can_add_hw = 0;
P
Peter Zijlstra 已提交
3002
		}
T
Thomas Gleixner 已提交
3003
	}
3004 3005 3006 3007 3008
}

static void
ctx_sched_in(struct perf_event_context *ctx,
	     struct perf_cpu_context *cpuctx,
S
Stephane Eranian 已提交
3009 3010
	     enum event_type_t event_type,
	     struct task_struct *task)
3011
{
3012
	int is_active = ctx->is_active;
P
Peter Zijlstra 已提交
3013 3014 3015
	u64 now;

	lockdep_assert_held(&ctx->lock);
S
Stephane Eranian 已提交
3016

3017
	if (likely(!ctx->nr_events))
3018
		return;
3019

3020
	ctx->is_active |= (event_type | EVENT_TIME);
3021 3022 3023 3024 3025 3026 3027
	if (ctx->task) {
		if (!is_active)
			cpuctx->task_ctx = ctx;
		else
			WARN_ON_ONCE(cpuctx->task_ctx != ctx);
	}

3028 3029 3030 3031 3032 3033 3034 3035 3036
	is_active ^= ctx->is_active; /* changed bits */

	if (is_active & EVENT_TIME) {
		/* start ctx time */
		now = perf_clock();
		ctx->timestamp = now;
		perf_cgroup_set_timestamp(task, ctx);
	}

3037 3038 3039 3040
	/*
	 * First go through the list and put on any pinned groups
	 * in order to give them the best chance of going on.
	 */
3041
	if (is_active & EVENT_PINNED)
3042
		ctx_pinned_sched_in(ctx, cpuctx);
3043 3044

	/* Then walk through the lower prio flexible groups */
3045
	if (is_active & EVENT_FLEXIBLE)
3046
		ctx_flexible_sched_in(ctx, cpuctx);
3047 3048
}

3049
static void cpu_ctx_sched_in(struct perf_cpu_context *cpuctx,
S
Stephane Eranian 已提交
3050 3051
			     enum event_type_t event_type,
			     struct task_struct *task)
3052 3053 3054
{
	struct perf_event_context *ctx = &cpuctx->ctx;

S
Stephane Eranian 已提交
3055
	ctx_sched_in(ctx, cpuctx, event_type, task);
3056 3057
}

S
Stephane Eranian 已提交
3058 3059
static void perf_event_context_sched_in(struct perf_event_context *ctx,
					struct task_struct *task)
3060
{
P
Peter Zijlstra 已提交
3061
	struct perf_cpu_context *cpuctx;
3062

P
Peter Zijlstra 已提交
3063
	cpuctx = __get_cpu_context(ctx);
3064 3065 3066
	if (cpuctx->task_ctx == ctx)
		return;

3067
	perf_ctx_lock(cpuctx, ctx);
P
Peter Zijlstra 已提交
3068
	perf_pmu_disable(ctx->pmu);
3069 3070 3071 3072 3073 3074
	/*
	 * We want to keep the following priority order:
	 * cpu pinned (that don't need to move), task pinned,
	 * cpu flexible, task flexible.
	 */
	cpu_ctx_sched_out(cpuctx, EVENT_FLEXIBLE);
3075
	perf_event_sched_in(cpuctx, ctx, task);
3076 3077
	perf_pmu_enable(ctx->pmu);
	perf_ctx_unlock(cpuctx, ctx);
3078 3079
}

P
Peter Zijlstra 已提交
3080 3081 3082 3083 3084 3085 3086 3087 3088 3089 3090
/*
 * Called from scheduler to add the events of the current task
 * with interrupts disabled.
 *
 * We restore the event value and then enable it.
 *
 * This does not protect us against NMI, but enable()
 * sets the enabled bit in the control field of event _before_
 * accessing the event control register. If a NMI hits, then it will
 * keep the event running.
 */
3091 3092
void __perf_event_task_sched_in(struct task_struct *prev,
				struct task_struct *task)
P
Peter Zijlstra 已提交
3093 3094 3095 3096
{
	struct perf_event_context *ctx;
	int ctxn;

3097 3098 3099 3100 3101 3102 3103 3104 3105 3106
	/*
	 * If cgroup events exist on this CPU, then we need to check if we have
	 * to switch in PMU state; cgroup event are system-wide mode only.
	 *
	 * Since cgroup events are CPU events, we must schedule these in before
	 * we schedule in the task events.
	 */
	if (atomic_read(this_cpu_ptr(&perf_cgroup_events)))
		perf_cgroup_sched_in(prev, task);

P
Peter Zijlstra 已提交
3107 3108 3109 3110 3111
	for_each_task_context_nr(ctxn) {
		ctx = task->perf_event_ctxp[ctxn];
		if (likely(!ctx))
			continue;

S
Stephane Eranian 已提交
3112
		perf_event_context_sched_in(ctx, task);
P
Peter Zijlstra 已提交
3113
	}
3114

3115 3116 3117
	if (atomic_read(&nr_switch_events))
		perf_event_switch(task, prev, true);

3118 3119
	if (__this_cpu_read(perf_sched_cb_usages))
		perf_pmu_sched_task(prev, task, true);
3120 3121
}

3122 3123 3124 3125 3126 3127 3128 3129 3130 3131 3132 3133 3134 3135 3136 3137 3138 3139 3140 3141 3142 3143 3144 3145 3146 3147 3148
static u64 perf_calculate_period(struct perf_event *event, u64 nsec, u64 count)
{
	u64 frequency = event->attr.sample_freq;
	u64 sec = NSEC_PER_SEC;
	u64 divisor, dividend;

	int count_fls, nsec_fls, frequency_fls, sec_fls;

	count_fls = fls64(count);
	nsec_fls = fls64(nsec);
	frequency_fls = fls64(frequency);
	sec_fls = 30;

	/*
	 * We got @count in @nsec, with a target of sample_freq HZ
	 * the target period becomes:
	 *
	 *             @count * 10^9
	 * period = -------------------
	 *          @nsec * sample_freq
	 *
	 */

	/*
	 * Reduce accuracy by one bit such that @a and @b converge
	 * to a similar magnitude.
	 */
3149
#define REDUCE_FLS(a, b)		\
3150 3151 3152 3153 3154 3155 3156 3157 3158 3159 3160 3161 3162 3163 3164 3165 3166 3167 3168 3169 3170 3171 3172 3173 3174 3175 3176 3177 3178 3179 3180 3181 3182 3183 3184 3185 3186 3187 3188
do {					\
	if (a##_fls > b##_fls) {	\
		a >>= 1;		\
		a##_fls--;		\
	} else {			\
		b >>= 1;		\
		b##_fls--;		\
	}				\
} while (0)

	/*
	 * Reduce accuracy until either term fits in a u64, then proceed with
	 * the other, so that finally we can do a u64/u64 division.
	 */
	while (count_fls + sec_fls > 64 && nsec_fls + frequency_fls > 64) {
		REDUCE_FLS(nsec, frequency);
		REDUCE_FLS(sec, count);
	}

	if (count_fls + sec_fls > 64) {
		divisor = nsec * frequency;

		while (count_fls + sec_fls > 64) {
			REDUCE_FLS(count, sec);
			divisor >>= 1;
		}

		dividend = count * sec;
	} else {
		dividend = count * sec;

		while (nsec_fls + frequency_fls > 64) {
			REDUCE_FLS(nsec, frequency);
			dividend >>= 1;
		}

		divisor = nsec * frequency;
	}

3189 3190 3191
	if (!divisor)
		return dividend;

3192 3193 3194
	return div64_u64(dividend, divisor);
}

3195 3196 3197
static DEFINE_PER_CPU(int, perf_throttled_count);
static DEFINE_PER_CPU(u64, perf_throttled_seq);

3198
static void perf_adjust_period(struct perf_event *event, u64 nsec, u64 count, bool disable)
3199
{
3200
	struct hw_perf_event *hwc = &event->hw;
3201
	s64 period, sample_period;
3202 3203
	s64 delta;

3204
	period = perf_calculate_period(event, nsec, count);
3205 3206 3207 3208 3209 3210 3211 3212 3213 3214

	delta = (s64)(period - hwc->sample_period);
	delta = (delta + 7) / 8; /* low pass filter */

	sample_period = hwc->sample_period + delta;

	if (!sample_period)
		sample_period = 1;

	hwc->sample_period = sample_period;
3215

3216
	if (local64_read(&hwc->period_left) > 8*sample_period) {
3217 3218 3219
		if (disable)
			event->pmu->stop(event, PERF_EF_UPDATE);

3220
		local64_set(&hwc->period_left, 0);
3221 3222 3223

		if (disable)
			event->pmu->start(event, PERF_EF_RELOAD);
3224
	}
3225 3226
}

3227 3228 3229 3230 3231 3232 3233
/*
 * combine freq adjustment with unthrottling to avoid two passes over the
 * events. At the same time, make sure, having freq events does not change
 * the rate of unthrottling as that would introduce bias.
 */
static void perf_adjust_freq_unthr_context(struct perf_event_context *ctx,
					   int needs_unthr)
3234
{
3235 3236
	struct perf_event *event;
	struct hw_perf_event *hwc;
3237
	u64 now, period = TICK_NSEC;
3238
	s64 delta;
3239

3240 3241 3242 3243 3244 3245
	/*
	 * only need to iterate over all events iff:
	 * - context have events in frequency mode (needs freq adjust)
	 * - there are events to unthrottle on this cpu
	 */
	if (!(ctx->nr_freq || needs_unthr))
3246 3247
		return;

3248
	raw_spin_lock(&ctx->lock);
3249
	perf_pmu_disable(ctx->pmu);
3250

3251
	list_for_each_entry_rcu(event, &ctx->event_list, event_entry) {
3252
		if (event->state != PERF_EVENT_STATE_ACTIVE)
3253 3254
			continue;

3255
		if (!event_filter_match(event))
3256 3257
			continue;

3258 3259
		perf_pmu_disable(event->pmu);

3260
		hwc = &event->hw;
3261

3262
		if (hwc->interrupts == MAX_INTERRUPTS) {
3263
			hwc->interrupts = 0;
3264
			perf_log_throttle(event, 1);
P
Peter Zijlstra 已提交
3265
			event->pmu->start(event, 0);
3266 3267
		}

3268
		if (!event->attr.freq || !event->attr.sample_freq)
3269
			goto next;
3270

3271 3272 3273 3274 3275
		/*
		 * stop the event and update event->count
		 */
		event->pmu->stop(event, PERF_EF_UPDATE);

3276
		now = local64_read(&event->count);
3277 3278
		delta = now - hwc->freq_count_stamp;
		hwc->freq_count_stamp = now;
3279

3280 3281 3282
		/*
		 * restart the event
		 * reload only if value has changed
3283 3284 3285
		 * we have stopped the event so tell that
		 * to perf_adjust_period() to avoid stopping it
		 * twice.
3286
		 */
3287
		if (delta > 0)
3288
			perf_adjust_period(event, period, delta, false);
3289 3290

		event->pmu->start(event, delta > 0 ? PERF_EF_RELOAD : 0);
3291 3292
	next:
		perf_pmu_enable(event->pmu);
3293
	}
3294

3295
	perf_pmu_enable(ctx->pmu);
3296
	raw_spin_unlock(&ctx->lock);
3297 3298
}

3299
/*
3300
 * Round-robin a context's events:
3301
 */
3302
static void rotate_ctx(struct perf_event_context *ctx)
T
Thomas Gleixner 已提交
3303
{
3304 3305 3306 3307 3308 3309
	/*
	 * Rotate the first entry last of non-pinned groups. Rotation might be
	 * disabled by the inheritance code.
	 */
	if (!ctx->rotate_disable)
		list_rotate_left(&ctx->flexible_groups);
3310 3311
}

3312
static int perf_rotate_context(struct perf_cpu_context *cpuctx)
3313
{
P
Peter Zijlstra 已提交
3314
	struct perf_event_context *ctx = NULL;
3315
	int rotate = 0;
3316

3317 3318 3319 3320
	if (cpuctx->ctx.nr_events) {
		if (cpuctx->ctx.nr_events != cpuctx->ctx.nr_active)
			rotate = 1;
	}
3321

P
Peter Zijlstra 已提交
3322
	ctx = cpuctx->task_ctx;
3323 3324 3325 3326
	if (ctx && ctx->nr_events) {
		if (ctx->nr_events != ctx->nr_active)
			rotate = 1;
	}
3327

3328
	if (!rotate)
3329 3330
		goto done;

3331
	perf_ctx_lock(cpuctx, cpuctx->task_ctx);
P
Peter Zijlstra 已提交
3332
	perf_pmu_disable(cpuctx->ctx.pmu);
3333

3334 3335 3336
	cpu_ctx_sched_out(cpuctx, EVENT_FLEXIBLE);
	if (ctx)
		ctx_sched_out(ctx, cpuctx, EVENT_FLEXIBLE);
T
Thomas Gleixner 已提交
3337

3338 3339 3340
	rotate_ctx(&cpuctx->ctx);
	if (ctx)
		rotate_ctx(ctx);
3341

3342
	perf_event_sched_in(cpuctx, ctx, current);
3343

3344 3345
	perf_pmu_enable(cpuctx->ctx.pmu);
	perf_ctx_unlock(cpuctx, cpuctx->task_ctx);
3346
done:
3347 3348

	return rotate;
3349 3350 3351 3352
}

void perf_event_task_tick(void)
{
3353 3354
	struct list_head *head = this_cpu_ptr(&active_ctx_list);
	struct perf_event_context *ctx, *tmp;
3355
	int throttled;
3356

3357 3358
	WARN_ON(!irqs_disabled());

3359 3360
	__this_cpu_inc(perf_throttled_seq);
	throttled = __this_cpu_xchg(perf_throttled_count, 0);
3361
	tick_dep_clear_cpu(smp_processor_id(), TICK_DEP_BIT_PERF_EVENTS);
3362

3363
	list_for_each_entry_safe(ctx, tmp, head, active_ctx_list)
3364
		perf_adjust_freq_unthr_context(ctx, throttled);
T
Thomas Gleixner 已提交
3365 3366
}

3367 3368 3369 3370 3371 3372 3373 3374 3375 3376
static int event_enable_on_exec(struct perf_event *event,
				struct perf_event_context *ctx)
{
	if (!event->attr.enable_on_exec)
		return 0;

	event->attr.enable_on_exec = 0;
	if (event->state >= PERF_EVENT_STATE_INACTIVE)
		return 0;

3377
	__perf_event_mark_enabled(event);
3378 3379 3380 3381

	return 1;
}

3382
/*
3383
 * Enable all of a task's events that have been marked enable-on-exec.
3384 3385
 * This expects task == current.
 */
3386
static void perf_event_enable_on_exec(int ctxn)
3387
{
3388
	struct perf_event_context *ctx, *clone_ctx = NULL;
3389
	struct perf_cpu_context *cpuctx;
3390
	struct perf_event *event;
3391 3392 3393 3394
	unsigned long flags;
	int enabled = 0;

	local_irq_save(flags);
3395
	ctx = current->perf_event_ctxp[ctxn];
3396
	if (!ctx || !ctx->nr_events)
3397 3398
		goto out;

3399 3400
	cpuctx = __get_cpu_context(ctx);
	perf_ctx_lock(cpuctx, ctx);
3401
	ctx_sched_out(ctx, cpuctx, EVENT_TIME);
3402 3403
	list_for_each_entry(event, &ctx->event_list, event_entry)
		enabled |= event_enable_on_exec(event, ctx);
3404 3405

	/*
3406
	 * Unclone and reschedule this context if we enabled any event.
3407
	 */
3408
	if (enabled) {
3409
		clone_ctx = unclone_ctx(ctx);
3410 3411 3412
		ctx_resched(cpuctx, ctx);
	}
	perf_ctx_unlock(cpuctx, ctx);
3413

P
Peter Zijlstra 已提交
3414
out:
3415
	local_irq_restore(flags);
3416 3417 3418

	if (clone_ctx)
		put_ctx(clone_ctx);
3419 3420
}

3421 3422 3423
struct perf_read_data {
	struct perf_event *event;
	bool group;
3424
	int ret;
3425 3426
};

T
Thomas Gleixner 已提交
3427
/*
3428
 * Cross CPU call to read the hardware event
T
Thomas Gleixner 已提交
3429
 */
3430
static void __perf_event_read(void *info)
T
Thomas Gleixner 已提交
3431
{
3432 3433
	struct perf_read_data *data = info;
	struct perf_event *sub, *event = data->event;
3434
	struct perf_event_context *ctx = event->ctx;
P
Peter Zijlstra 已提交
3435
	struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
3436
	struct pmu *pmu = event->pmu;
I
Ingo Molnar 已提交
3437

3438 3439 3440 3441
	/*
	 * If this is a task context, we need to check whether it is
	 * the current task context of this cpu.  If not it has been
	 * scheduled out before the smp call arrived.  In that case
3442 3443
	 * event->count would have been updated to a recent sample
	 * when the event was scheduled out.
3444 3445 3446 3447
	 */
	if (ctx->task && cpuctx->task_ctx != ctx)
		return;

3448
	raw_spin_lock(&ctx->lock);
S
Stephane Eranian 已提交
3449
	if (ctx->is_active) {
3450
		update_context_time(ctx);
S
Stephane Eranian 已提交
3451 3452
		update_cgrp_time_from_event(event);
	}
3453

3454
	update_event_times(event);
3455 3456
	if (event->state != PERF_EVENT_STATE_ACTIVE)
		goto unlock;
3457

3458 3459 3460
	if (!data->group) {
		pmu->read(event);
		data->ret = 0;
3461
		goto unlock;
3462 3463 3464 3465 3466
	}

	pmu->start_txn(pmu, PERF_PMU_TXN_READ);

	pmu->read(event);
3467 3468 3469

	list_for_each_entry(sub, &event->sibling_list, group_entry) {
		update_event_times(sub);
3470 3471 3472 3473 3474
		if (sub->state == PERF_EVENT_STATE_ACTIVE) {
			/*
			 * Use sibling's PMU rather than @event's since
			 * sibling could be on different (eg: software) PMU.
			 */
3475
			sub->pmu->read(sub);
3476
		}
3477
	}
3478 3479

	data->ret = pmu->commit_txn(pmu);
3480 3481

unlock:
3482
	raw_spin_unlock(&ctx->lock);
T
Thomas Gleixner 已提交
3483 3484
}

P
Peter Zijlstra 已提交
3485 3486
static inline u64 perf_event_count(struct perf_event *event)
{
3487 3488 3489 3490
	if (event->pmu->count)
		return event->pmu->count(event);

	return __perf_event_count(event);
P
Peter Zijlstra 已提交
3491 3492
}

3493 3494 3495 3496 3497 3498 3499 3500 3501 3502 3503 3504 3505 3506 3507 3508 3509 3510 3511 3512 3513 3514 3515 3516 3517 3518 3519 3520 3521 3522 3523 3524 3525 3526 3527 3528 3529 3530 3531 3532 3533 3534 3535 3536 3537 3538 3539 3540 3541 3542 3543 3544 3545
/*
 * NMI-safe method to read a local event, that is an event that
 * is:
 *   - either for the current task, or for this CPU
 *   - does not have inherit set, for inherited task events
 *     will not be local and we cannot read them atomically
 *   - must not have a pmu::count method
 */
u64 perf_event_read_local(struct perf_event *event)
{
	unsigned long flags;
	u64 val;

	/*
	 * Disabling interrupts avoids all counter scheduling (context
	 * switches, timer based rotation and IPIs).
	 */
	local_irq_save(flags);

	/* If this is a per-task event, it must be for current */
	WARN_ON_ONCE((event->attach_state & PERF_ATTACH_TASK) &&
		     event->hw.target != current);

	/* If this is a per-CPU event, it must be for this CPU */
	WARN_ON_ONCE(!(event->attach_state & PERF_ATTACH_TASK) &&
		     event->cpu != smp_processor_id());

	/*
	 * It must not be an event with inherit set, we cannot read
	 * all child counters from atomic context.
	 */
	WARN_ON_ONCE(event->attr.inherit);

	/*
	 * It must not have a pmu::count method, those are not
	 * NMI safe.
	 */
	WARN_ON_ONCE(event->pmu->count);

	/*
	 * If the event is currently on this CPU, its either a per-task event,
	 * or local to this CPU. Furthermore it means its ACTIVE (otherwise
	 * oncpu == -1).
	 */
	if (event->oncpu == smp_processor_id())
		event->pmu->read(event);

	val = local64_read(&event->count);
	local_irq_restore(flags);

	return val;
}

3546
static int perf_event_read(struct perf_event *event, bool group)
T
Thomas Gleixner 已提交
3547
{
3548 3549
	int ret = 0;

T
Thomas Gleixner 已提交
3550
	/*
3551 3552
	 * If event is enabled and currently active on a CPU, update the
	 * value in the event structure:
T
Thomas Gleixner 已提交
3553
	 */
3554
	if (event->state == PERF_EVENT_STATE_ACTIVE) {
3555 3556 3557
		struct perf_read_data data = {
			.event = event,
			.group = group,
3558
			.ret = 0,
3559
		};
3560 3561 3562 3563
		ret = smp_call_function_single(event->oncpu, __perf_event_read, &data, 1);
		/* The event must have been read from an online CPU: */
		WARN_ON_ONCE(ret);
		ret = ret ? : data.ret;
3564
	} else if (event->state == PERF_EVENT_STATE_INACTIVE) {
P
Peter Zijlstra 已提交
3565 3566 3567
		struct perf_event_context *ctx = event->ctx;
		unsigned long flags;

3568
		raw_spin_lock_irqsave(&ctx->lock, flags);
3569 3570 3571 3572 3573
		/*
		 * may read while context is not active
		 * (e.g., thread is blocked), in that case
		 * we cannot update context time
		 */
S
Stephane Eranian 已提交
3574
		if (ctx->is_active) {
3575
			update_context_time(ctx);
S
Stephane Eranian 已提交
3576 3577
			update_cgrp_time_from_event(event);
		}
3578 3579 3580 3581
		if (group)
			update_group_times(event);
		else
			update_event_times(event);
3582
		raw_spin_unlock_irqrestore(&ctx->lock, flags);
T
Thomas Gleixner 已提交
3583
	}
3584 3585

	return ret;
T
Thomas Gleixner 已提交
3586 3587
}

3588
/*
3589
 * Initialize the perf_event context in a task_struct:
3590
 */
3591
static void __perf_event_init_context(struct perf_event_context *ctx)
3592
{
3593
	raw_spin_lock_init(&ctx->lock);
3594
	mutex_init(&ctx->mutex);
3595
	INIT_LIST_HEAD(&ctx->active_ctx_list);
3596 3597
	INIT_LIST_HEAD(&ctx->pinned_groups);
	INIT_LIST_HEAD(&ctx->flexible_groups);
3598 3599
	INIT_LIST_HEAD(&ctx->event_list);
	atomic_set(&ctx->refcount, 1);
3600 3601 3602 3603 3604 3605 3606 3607 3608 3609 3610 3611 3612 3613 3614
}

static struct perf_event_context *
alloc_perf_context(struct pmu *pmu, struct task_struct *task)
{
	struct perf_event_context *ctx;

	ctx = kzalloc(sizeof(struct perf_event_context), GFP_KERNEL);
	if (!ctx)
		return NULL;

	__perf_event_init_context(ctx);
	if (task) {
		ctx->task = task;
		get_task_struct(task);
T
Thomas Gleixner 已提交
3615
	}
3616 3617 3618
	ctx->pmu = pmu;

	return ctx;
3619 3620
}

3621 3622 3623 3624
static struct task_struct *
find_lively_task_by_vpid(pid_t vpid)
{
	struct task_struct *task;
T
Thomas Gleixner 已提交
3625 3626

	rcu_read_lock();
3627
	if (!vpid)
T
Thomas Gleixner 已提交
3628 3629
		task = current;
	else
3630
		task = find_task_by_vpid(vpid);
T
Thomas Gleixner 已提交
3631 3632 3633 3634 3635 3636 3637
	if (task)
		get_task_struct(task);
	rcu_read_unlock();

	if (!task)
		return ERR_PTR(-ESRCH);

3638 3639 3640
	return task;
}

3641 3642 3643
/*
 * Returns a matching context with refcount and pincount.
 */
P
Peter Zijlstra 已提交
3644
static struct perf_event_context *
3645 3646
find_get_context(struct pmu *pmu, struct task_struct *task,
		struct perf_event *event)
T
Thomas Gleixner 已提交
3647
{
3648
	struct perf_event_context *ctx, *clone_ctx = NULL;
3649
	struct perf_cpu_context *cpuctx;
3650
	void *task_ctx_data = NULL;
3651
	unsigned long flags;
P
Peter Zijlstra 已提交
3652
	int ctxn, err;
3653
	int cpu = event->cpu;
T
Thomas Gleixner 已提交
3654

3655
	if (!task) {
3656
		/* Must be root to operate on a CPU event: */
3657
		if (perf_paranoid_cpu() && !capable(CAP_SYS_ADMIN))
T
Thomas Gleixner 已提交
3658 3659 3660
			return ERR_PTR(-EACCES);

		/*
3661
		 * We could be clever and allow to attach a event to an
T
Thomas Gleixner 已提交
3662 3663 3664
		 * offline CPU and activate it when the CPU comes up, but
		 * that's for later.
		 */
3665
		if (!cpu_online(cpu))
T
Thomas Gleixner 已提交
3666 3667
			return ERR_PTR(-ENODEV);

P
Peter Zijlstra 已提交
3668
		cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
T
Thomas Gleixner 已提交
3669
		ctx = &cpuctx->ctx;
3670
		get_ctx(ctx);
3671
		++ctx->pin_count;
T
Thomas Gleixner 已提交
3672 3673 3674 3675

		return ctx;
	}

P
Peter Zijlstra 已提交
3676 3677 3678 3679 3680
	err = -EINVAL;
	ctxn = pmu->task_ctx_nr;
	if (ctxn < 0)
		goto errout;

3681 3682 3683 3684 3685 3686 3687 3688
	if (event->attach_state & PERF_ATTACH_TASK_DATA) {
		task_ctx_data = kzalloc(pmu->task_ctx_size, GFP_KERNEL);
		if (!task_ctx_data) {
			err = -ENOMEM;
			goto errout;
		}
	}

P
Peter Zijlstra 已提交
3689
retry:
P
Peter Zijlstra 已提交
3690
	ctx = perf_lock_task_context(task, ctxn, &flags);
3691
	if (ctx) {
3692
		clone_ctx = unclone_ctx(ctx);
3693
		++ctx->pin_count;
3694 3695 3696 3697 3698

		if (task_ctx_data && !ctx->task_ctx_data) {
			ctx->task_ctx_data = task_ctx_data;
			task_ctx_data = NULL;
		}
3699
		raw_spin_unlock_irqrestore(&ctx->lock, flags);
3700 3701 3702

		if (clone_ctx)
			put_ctx(clone_ctx);
3703
	} else {
3704
		ctx = alloc_perf_context(pmu, task);
3705 3706 3707
		err = -ENOMEM;
		if (!ctx)
			goto errout;
3708

3709 3710 3711 3712 3713
		if (task_ctx_data) {
			ctx->task_ctx_data = task_ctx_data;
			task_ctx_data = NULL;
		}

3714 3715 3716 3717 3718 3719 3720 3721 3722 3723
		err = 0;
		mutex_lock(&task->perf_event_mutex);
		/*
		 * If it has already passed perf_event_exit_task().
		 * we must see PF_EXITING, it takes this mutex too.
		 */
		if (task->flags & PF_EXITING)
			err = -ESRCH;
		else if (task->perf_event_ctxp[ctxn])
			err = -EAGAIN;
3724
		else {
3725
			get_ctx(ctx);
3726
			++ctx->pin_count;
3727
			rcu_assign_pointer(task->perf_event_ctxp[ctxn], ctx);
3728
		}
3729 3730 3731
		mutex_unlock(&task->perf_event_mutex);

		if (unlikely(err)) {
3732
			put_ctx(ctx);
3733 3734 3735 3736

			if (err == -EAGAIN)
				goto retry;
			goto errout;
3737 3738 3739
		}
	}

3740
	kfree(task_ctx_data);
T
Thomas Gleixner 已提交
3741
	return ctx;
3742

P
Peter Zijlstra 已提交
3743
errout:
3744
	kfree(task_ctx_data);
3745
	return ERR_PTR(err);
T
Thomas Gleixner 已提交
3746 3747
}

L
Li Zefan 已提交
3748
static void perf_event_free_filter(struct perf_event *event);
3749
static void perf_event_free_bpf_prog(struct perf_event *event);
L
Li Zefan 已提交
3750

3751
static void free_event_rcu(struct rcu_head *head)
P
Peter Zijlstra 已提交
3752
{
3753
	struct perf_event *event;
P
Peter Zijlstra 已提交
3754

3755 3756 3757
	event = container_of(head, struct perf_event, rcu_head);
	if (event->ns)
		put_pid_ns(event->ns);
L
Li Zefan 已提交
3758
	perf_event_free_filter(event);
3759
	kfree(event);
P
Peter Zijlstra 已提交
3760 3761
}

3762 3763
static void ring_buffer_attach(struct perf_event *event,
			       struct ring_buffer *rb);
3764

3765 3766 3767 3768 3769 3770 3771 3772 3773
static void detach_sb_event(struct perf_event *event)
{
	struct pmu_event_list *pel = per_cpu_ptr(&pmu_sb_events, event->cpu);

	raw_spin_lock(&pel->lock);
	list_del_rcu(&event->sb_list);
	raw_spin_unlock(&pel->lock);
}

3774
static bool is_sb_event(struct perf_event *event)
3775
{
3776 3777
	struct perf_event_attr *attr = &event->attr;

3778
	if (event->parent)
3779
		return false;
3780 3781

	if (event->attach_state & PERF_ATTACH_TASK)
3782
		return false;
3783

3784 3785 3786 3787 3788 3789 3790 3791 3792 3793 3794 3795
	if (attr->mmap || attr->mmap_data || attr->mmap2 ||
	    attr->comm || attr->comm_exec ||
	    attr->task ||
	    attr->context_switch)
		return true;
	return false;
}

static void unaccount_pmu_sb_event(struct perf_event *event)
{
	if (is_sb_event(event))
		detach_sb_event(event);
3796 3797
}

3798
static void unaccount_event_cpu(struct perf_event *event, int cpu)
3799
{
3800 3801 3802 3803 3804 3805
	if (event->parent)
		return;

	if (is_cgroup_event(event))
		atomic_dec(&per_cpu(perf_cgroup_events, cpu));
}
3806

3807 3808 3809 3810 3811 3812 3813 3814 3815 3816 3817 3818 3819 3820 3821 3822 3823 3824 3825 3826 3827 3828
#ifdef CONFIG_NO_HZ_FULL
static DEFINE_SPINLOCK(nr_freq_lock);
#endif

static void unaccount_freq_event_nohz(void)
{
#ifdef CONFIG_NO_HZ_FULL
	spin_lock(&nr_freq_lock);
	if (atomic_dec_and_test(&nr_freq_events))
		tick_nohz_dep_clear(TICK_DEP_BIT_PERF_EVENTS);
	spin_unlock(&nr_freq_lock);
#endif
}

static void unaccount_freq_event(void)
{
	if (tick_nohz_full_enabled())
		unaccount_freq_event_nohz();
	else
		atomic_dec(&nr_freq_events);
}

3829 3830
static void unaccount_event(struct perf_event *event)
{
3831 3832
	bool dec = false;

3833 3834 3835 3836
	if (event->parent)
		return;

	if (event->attach_state & PERF_ATTACH_TASK)
3837
		dec = true;
3838 3839 3840 3841 3842 3843
	if (event->attr.mmap || event->attr.mmap_data)
		atomic_dec(&nr_mmap_events);
	if (event->attr.comm)
		atomic_dec(&nr_comm_events);
	if (event->attr.task)
		atomic_dec(&nr_task_events);
3844
	if (event->attr.freq)
3845
		unaccount_freq_event();
3846
	if (event->attr.context_switch) {
3847
		dec = true;
3848 3849
		atomic_dec(&nr_switch_events);
	}
3850
	if (is_cgroup_event(event))
3851
		dec = true;
3852
	if (has_branch_stack(event))
3853 3854
		dec = true;

3855 3856 3857 3858
	if (dec) {
		if (!atomic_add_unless(&perf_sched_count, -1, 1))
			schedule_delayed_work(&perf_sched_work, HZ);
	}
3859 3860

	unaccount_event_cpu(event, event->cpu);
3861 3862

	unaccount_pmu_sb_event(event);
3863
}
3864

3865 3866 3867 3868 3869 3870 3871 3872
static void perf_sched_delayed(struct work_struct *work)
{
	mutex_lock(&perf_sched_mutex);
	if (atomic_dec_and_test(&perf_sched_count))
		static_branch_disable(&perf_sched_events);
	mutex_unlock(&perf_sched_mutex);
}

3873 3874 3875 3876 3877 3878 3879 3880 3881 3882
/*
 * The following implement mutual exclusion of events on "exclusive" pmus
 * (PERF_PMU_CAP_EXCLUSIVE). Such pmus can only have one event scheduled
 * at a time, so we disallow creating events that might conflict, namely:
 *
 *  1) cpu-wide events in the presence of per-task events,
 *  2) per-task events in the presence of cpu-wide events,
 *  3) two matching events on the same context.
 *
 * The former two cases are handled in the allocation path (perf_event_alloc(),
P
Peter Zijlstra 已提交
3883
 * _free_event()), the latter -- before the first perf_install_in_context().
3884 3885 3886 3887 3888 3889 3890 3891 3892 3893 3894 3895 3896 3897 3898 3899 3900 3901 3902 3903 3904 3905 3906 3907 3908 3909 3910 3911 3912 3913 3914 3915 3916 3917 3918 3919 3920 3921 3922 3923 3924 3925 3926 3927 3928 3929 3930 3931 3932 3933 3934 3935 3936 3937 3938 3939 3940 3941 3942 3943 3944 3945 3946 3947 3948 3949 3950 3951 3952 3953 3954 3955 3956 3957
 */
static int exclusive_event_init(struct perf_event *event)
{
	struct pmu *pmu = event->pmu;

	if (!(pmu->capabilities & PERF_PMU_CAP_EXCLUSIVE))
		return 0;

	/*
	 * Prevent co-existence of per-task and cpu-wide events on the
	 * same exclusive pmu.
	 *
	 * Negative pmu::exclusive_cnt means there are cpu-wide
	 * events on this "exclusive" pmu, positive means there are
	 * per-task events.
	 *
	 * Since this is called in perf_event_alloc() path, event::ctx
	 * doesn't exist yet; it is, however, safe to use PERF_ATTACH_TASK
	 * to mean "per-task event", because unlike other attach states it
	 * never gets cleared.
	 */
	if (event->attach_state & PERF_ATTACH_TASK) {
		if (!atomic_inc_unless_negative(&pmu->exclusive_cnt))
			return -EBUSY;
	} else {
		if (!atomic_dec_unless_positive(&pmu->exclusive_cnt))
			return -EBUSY;
	}

	return 0;
}

static void exclusive_event_destroy(struct perf_event *event)
{
	struct pmu *pmu = event->pmu;

	if (!(pmu->capabilities & PERF_PMU_CAP_EXCLUSIVE))
		return;

	/* see comment in exclusive_event_init() */
	if (event->attach_state & PERF_ATTACH_TASK)
		atomic_dec(&pmu->exclusive_cnt);
	else
		atomic_inc(&pmu->exclusive_cnt);
}

static bool exclusive_event_match(struct perf_event *e1, struct perf_event *e2)
{
	if ((e1->pmu->capabilities & PERF_PMU_CAP_EXCLUSIVE) &&
	    (e1->cpu == e2->cpu ||
	     e1->cpu == -1 ||
	     e2->cpu == -1))
		return true;
	return false;
}

/* Called under the same ctx::mutex as perf_install_in_context() */
static bool exclusive_event_installable(struct perf_event *event,
					struct perf_event_context *ctx)
{
	struct perf_event *iter_event;
	struct pmu *pmu = event->pmu;

	if (!(pmu->capabilities & PERF_PMU_CAP_EXCLUSIVE))
		return true;

	list_for_each_entry(iter_event, &ctx->event_list, event_entry) {
		if (exclusive_event_match(iter_event, event))
			return false;
	}

	return true;
}

3958 3959 3960
static void perf_addr_filters_splice(struct perf_event *event,
				       struct list_head *head);

P
Peter Zijlstra 已提交
3961
static void _free_event(struct perf_event *event)
3962
{
3963
	irq_work_sync(&event->pending);
3964

3965
	unaccount_event(event);
3966

3967
	if (event->rb) {
3968 3969 3970 3971 3972 3973 3974
		/*
		 * Can happen when we close an event with re-directed output.
		 *
		 * Since we have a 0 refcount, perf_mmap_close() will skip
		 * over us; possibly making our ring_buffer_put() the last.
		 */
		mutex_lock(&event->mmap_mutex);
3975
		ring_buffer_attach(event, NULL);
3976
		mutex_unlock(&event->mmap_mutex);
3977 3978
	}

S
Stephane Eranian 已提交
3979 3980 3981
	if (is_cgroup_event(event))
		perf_detach_cgroup(event);

P
Peter Zijlstra 已提交
3982 3983 3984 3985 3986 3987
	if (!event->parent) {
		if (event->attr.sample_type & PERF_SAMPLE_CALLCHAIN)
			put_callchain_buffers();
	}

	perf_event_free_bpf_prog(event);
3988 3989
	perf_addr_filters_splice(event, NULL);
	kfree(event->addr_filters_offs);
P
Peter Zijlstra 已提交
3990 3991 3992 3993 3994 3995 3996

	if (event->destroy)
		event->destroy(event);

	if (event->ctx)
		put_ctx(event->ctx);

3997 3998
	exclusive_event_destroy(event);
	module_put(event->pmu->module);
P
Peter Zijlstra 已提交
3999 4000

	call_rcu(&event->rcu_head, free_event_rcu);
4001 4002
}

P
Peter Zijlstra 已提交
4003 4004 4005 4006 4007
/*
 * Used to free events which have a known refcount of 1, such as in error paths
 * where the event isn't exposed yet and inherited events.
 */
static void free_event(struct perf_event *event)
T
Thomas Gleixner 已提交
4008
{
P
Peter Zijlstra 已提交
4009 4010 4011 4012 4013 4014
	if (WARN(atomic_long_cmpxchg(&event->refcount, 1, 0) != 1,
				"unexpected event refcount: %ld; ptr=%p\n",
				atomic_long_read(&event->refcount), event)) {
		/* leak to avoid use-after-free */
		return;
	}
T
Thomas Gleixner 已提交
4015

P
Peter Zijlstra 已提交
4016
	_free_event(event);
T
Thomas Gleixner 已提交
4017 4018
}

4019
/*
4020
 * Remove user event from the owner task.
4021
 */
4022
static void perf_remove_from_owner(struct perf_event *event)
4023
{
P
Peter Zijlstra 已提交
4024
	struct task_struct *owner;
4025

P
Peter Zijlstra 已提交
4026 4027
	rcu_read_lock();
	/*
4028 4029 4030
	 * Matches the smp_store_release() in perf_event_exit_task(). If we
	 * observe !owner it means the list deletion is complete and we can
	 * indeed free this event, otherwise we need to serialize on
P
Peter Zijlstra 已提交
4031 4032
	 * owner->perf_event_mutex.
	 */
4033
	owner = lockless_dereference(event->owner);
P
Peter Zijlstra 已提交
4034 4035 4036 4037 4038 4039 4040 4041 4042 4043 4044
	if (owner) {
		/*
		 * Since delayed_put_task_struct() also drops the last
		 * task reference we can safely take a new reference
		 * while holding the rcu_read_lock().
		 */
		get_task_struct(owner);
	}
	rcu_read_unlock();

	if (owner) {
P
Peter Zijlstra 已提交
4045 4046 4047 4048 4049 4050 4051 4052 4053 4054
		/*
		 * If we're here through perf_event_exit_task() we're already
		 * holding ctx->mutex which would be an inversion wrt. the
		 * normal lock order.
		 *
		 * However we can safely take this lock because its the child
		 * ctx->mutex.
		 */
		mutex_lock_nested(&owner->perf_event_mutex, SINGLE_DEPTH_NESTING);

P
Peter Zijlstra 已提交
4055 4056 4057 4058 4059 4060
		/*
		 * We have to re-check the event->owner field, if it is cleared
		 * we raced with perf_event_exit_task(), acquiring the mutex
		 * ensured they're done, and we can proceed with freeing the
		 * event.
		 */
4061
		if (event->owner) {
P
Peter Zijlstra 已提交
4062
			list_del_init(&event->owner_entry);
4063 4064
			smp_store_release(&event->owner, NULL);
		}
P
Peter Zijlstra 已提交
4065 4066 4067
		mutex_unlock(&owner->perf_event_mutex);
		put_task_struct(owner);
	}
4068 4069 4070 4071 4072 4073 4074
}

static void put_event(struct perf_event *event)
{
	if (!atomic_long_dec_and_test(&event->refcount))
		return;

4075 4076 4077 4078 4079 4080 4081 4082 4083 4084
	_free_event(event);
}

/*
 * Kill an event dead; while event:refcount will preserve the event
 * object, it will not preserve its functionality. Once the last 'user'
 * gives up the object, we'll destroy the thing.
 */
int perf_event_release_kernel(struct perf_event *event)
{
4085
	struct perf_event_context *ctx = event->ctx;
4086 4087
	struct perf_event *child, *tmp;

4088 4089 4090 4091 4092 4093 4094 4095 4096 4097
	/*
	 * If we got here through err_file: fput(event_file); we will not have
	 * attached to a context yet.
	 */
	if (!ctx) {
		WARN_ON_ONCE(event->attach_state &
				(PERF_ATTACH_CONTEXT|PERF_ATTACH_GROUP));
		goto no_ctx;
	}

4098 4099
	if (!is_kernel_event(event))
		perf_remove_from_owner(event);
P
Peter Zijlstra 已提交
4100

4101
	ctx = perf_event_ctx_lock(event);
P
Peter Zijlstra 已提交
4102
	WARN_ON_ONCE(ctx->parent_ctx);
P
Peter Zijlstra 已提交
4103
	perf_remove_from_context(event, DETACH_GROUP);
P
Peter Zijlstra 已提交
4104

P
Peter Zijlstra 已提交
4105
	raw_spin_lock_irq(&ctx->lock);
P
Peter Zijlstra 已提交
4106
	/*
P
Peter Zijlstra 已提交
4107 4108
	 * Mark this even as STATE_DEAD, there is no external reference to it
	 * anymore.
P
Peter Zijlstra 已提交
4109
	 *
P
Peter Zijlstra 已提交
4110 4111 4112
	 * Anybody acquiring event->child_mutex after the below loop _must_
	 * also see this, most importantly inherit_event() which will avoid
	 * placing more children on the list.
P
Peter Zijlstra 已提交
4113
	 *
4114 4115
	 * Thus this guarantees that we will in fact observe and kill _ALL_
	 * child events.
P
Peter Zijlstra 已提交
4116
	 */
P
Peter Zijlstra 已提交
4117 4118 4119 4120
	event->state = PERF_EVENT_STATE_DEAD;
	raw_spin_unlock_irq(&ctx->lock);

	perf_event_ctx_unlock(event, ctx);
P
Peter Zijlstra 已提交
4121

4122 4123 4124
again:
	mutex_lock(&event->child_mutex);
	list_for_each_entry(child, &event->child_list, child_list) {
4125

4126 4127 4128 4129 4130 4131 4132 4133 4134 4135 4136 4137 4138 4139 4140 4141 4142 4143 4144 4145 4146 4147 4148 4149 4150 4151 4152 4153 4154 4155 4156 4157 4158 4159 4160 4161 4162 4163 4164 4165 4166 4167 4168 4169 4170 4171 4172 4173 4174
		/*
		 * Cannot change, child events are not migrated, see the
		 * comment with perf_event_ctx_lock_nested().
		 */
		ctx = lockless_dereference(child->ctx);
		/*
		 * Since child_mutex nests inside ctx::mutex, we must jump
		 * through hoops. We start by grabbing a reference on the ctx.
		 *
		 * Since the event cannot get freed while we hold the
		 * child_mutex, the context must also exist and have a !0
		 * reference count.
		 */
		get_ctx(ctx);

		/*
		 * Now that we have a ctx ref, we can drop child_mutex, and
		 * acquire ctx::mutex without fear of it going away. Then we
		 * can re-acquire child_mutex.
		 */
		mutex_unlock(&event->child_mutex);
		mutex_lock(&ctx->mutex);
		mutex_lock(&event->child_mutex);

		/*
		 * Now that we hold ctx::mutex and child_mutex, revalidate our
		 * state, if child is still the first entry, it didn't get freed
		 * and we can continue doing so.
		 */
		tmp = list_first_entry_or_null(&event->child_list,
					       struct perf_event, child_list);
		if (tmp == child) {
			perf_remove_from_context(child, DETACH_GROUP);
			list_del(&child->child_list);
			free_event(child);
			/*
			 * This matches the refcount bump in inherit_event();
			 * this can't be the last reference.
			 */
			put_event(event);
		}

		mutex_unlock(&event->child_mutex);
		mutex_unlock(&ctx->mutex);
		put_ctx(ctx);
		goto again;
	}
	mutex_unlock(&event->child_mutex);

4175 4176
no_ctx:
	put_event(event); /* Must be the 'last' reference */
P
Peter Zijlstra 已提交
4177 4178 4179 4180
	return 0;
}
EXPORT_SYMBOL_GPL(perf_event_release_kernel);

4181 4182 4183
/*
 * Called when the last reference to the file is gone.
 */
4184 4185
static int perf_release(struct inode *inode, struct file *file)
{
4186
	perf_event_release_kernel(file->private_data);
4187
	return 0;
4188 4189
}

4190
u64 perf_event_read_value(struct perf_event *event, u64 *enabled, u64 *running)
4191
{
4192
	struct perf_event *child;
4193 4194
	u64 total = 0;

4195 4196 4197
	*enabled = 0;
	*running = 0;

4198
	mutex_lock(&event->child_mutex);
4199

4200
	(void)perf_event_read(event, false);
4201 4202
	total += perf_event_count(event);

4203 4204 4205 4206 4207 4208
	*enabled += event->total_time_enabled +
			atomic64_read(&event->child_total_time_enabled);
	*running += event->total_time_running +
			atomic64_read(&event->child_total_time_running);

	list_for_each_entry(child, &event->child_list, child_list) {
4209
		(void)perf_event_read(child, false);
4210
		total += perf_event_count(child);
4211 4212 4213
		*enabled += child->total_time_enabled;
		*running += child->total_time_running;
	}
4214
	mutex_unlock(&event->child_mutex);
4215 4216 4217

	return total;
}
4218
EXPORT_SYMBOL_GPL(perf_event_read_value);
4219

4220
static int __perf_read_group_add(struct perf_event *leader,
4221
					u64 read_format, u64 *values)
4222
{
4223 4224
	struct perf_event *sub;
	int n = 1; /* skip @nr */
4225
	int ret;
P
Peter Zijlstra 已提交
4226

4227 4228 4229
	ret = perf_event_read(leader, true);
	if (ret)
		return ret;
4230

4231 4232 4233 4234 4235 4236 4237 4238 4239
	/*
	 * Since we co-schedule groups, {enabled,running} times of siblings
	 * will be identical to those of the leader, so we only publish one
	 * set.
	 */
	if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED) {
		values[n++] += leader->total_time_enabled +
			atomic64_read(&leader->child_total_time_enabled);
	}
4240

4241 4242 4243 4244 4245 4246 4247 4248 4249
	if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING) {
		values[n++] += leader->total_time_running +
			atomic64_read(&leader->child_total_time_running);
	}

	/*
	 * Write {count,id} tuples for every sibling.
	 */
	values[n++] += perf_event_count(leader);
4250 4251
	if (read_format & PERF_FORMAT_ID)
		values[n++] = primary_event_id(leader);
4252

4253 4254 4255 4256 4257
	list_for_each_entry(sub, &leader->sibling_list, group_entry) {
		values[n++] += perf_event_count(sub);
		if (read_format & PERF_FORMAT_ID)
			values[n++] = primary_event_id(sub);
	}
4258 4259

	return 0;
4260
}
4261

4262 4263 4264 4265 4266
static int perf_read_group(struct perf_event *event,
				   u64 read_format, char __user *buf)
{
	struct perf_event *leader = event->group_leader, *child;
	struct perf_event_context *ctx = leader->ctx;
4267
	int ret;
4268
	u64 *values;
4269

4270
	lockdep_assert_held(&ctx->mutex);
4271

4272 4273 4274
	values = kzalloc(event->read_size, GFP_KERNEL);
	if (!values)
		return -ENOMEM;
4275

4276 4277 4278 4279 4280 4281 4282
	values[0] = 1 + leader->nr_siblings;

	/*
	 * By locking the child_mutex of the leader we effectively
	 * lock the child list of all siblings.. XXX explain how.
	 */
	mutex_lock(&leader->child_mutex);
4283

4284 4285 4286 4287 4288 4289 4290 4291 4292
	ret = __perf_read_group_add(leader, read_format, values);
	if (ret)
		goto unlock;

	list_for_each_entry(child, &leader->child_list, child_list) {
		ret = __perf_read_group_add(child, read_format, values);
		if (ret)
			goto unlock;
	}
4293

4294
	mutex_unlock(&leader->child_mutex);
4295

4296
	ret = event->read_size;
4297 4298
	if (copy_to_user(buf, values, event->read_size))
		ret = -EFAULT;
4299
	goto out;
4300

4301 4302 4303
unlock:
	mutex_unlock(&leader->child_mutex);
out:
4304
	kfree(values);
4305
	return ret;
4306 4307
}

4308
static int perf_read_one(struct perf_event *event,
4309 4310
				 u64 read_format, char __user *buf)
{
4311
	u64 enabled, running;
4312 4313 4314
	u64 values[4];
	int n = 0;

4315 4316 4317 4318 4319
	values[n++] = perf_event_read_value(event, &enabled, &running);
	if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED)
		values[n++] = enabled;
	if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING)
		values[n++] = running;
4320
	if (read_format & PERF_FORMAT_ID)
4321
		values[n++] = primary_event_id(event);
4322 4323 4324 4325 4326 4327 4328

	if (copy_to_user(buf, values, n * sizeof(u64)))
		return -EFAULT;

	return n * sizeof(u64);
}

4329 4330 4331 4332
static bool is_event_hup(struct perf_event *event)
{
	bool no_children;

P
Peter Zijlstra 已提交
4333
	if (event->state > PERF_EVENT_STATE_EXIT)
4334 4335 4336 4337 4338 4339 4340 4341
		return false;

	mutex_lock(&event->child_mutex);
	no_children = list_empty(&event->child_list);
	mutex_unlock(&event->child_mutex);
	return no_children;
}

T
Thomas Gleixner 已提交
4342
/*
4343
 * Read the performance event - simple non blocking version for now
T
Thomas Gleixner 已提交
4344 4345
 */
static ssize_t
4346
__perf_read(struct perf_event *event, char __user *buf, size_t count)
T
Thomas Gleixner 已提交
4347
{
4348
	u64 read_format = event->attr.read_format;
4349
	int ret;
T
Thomas Gleixner 已提交
4350

4351
	/*
4352
	 * Return end-of-file for a read on a event that is in
4353 4354 4355
	 * error state (i.e. because it was pinned but it couldn't be
	 * scheduled on to the CPU at some point).
	 */
4356
	if (event->state == PERF_EVENT_STATE_ERROR)
4357 4358
		return 0;

4359
	if (count < event->read_size)
4360 4361
		return -ENOSPC;

4362
	WARN_ON_ONCE(event->ctx->parent_ctx);
4363
	if (read_format & PERF_FORMAT_GROUP)
4364
		ret = perf_read_group(event, read_format, buf);
4365
	else
4366
		ret = perf_read_one(event, read_format, buf);
T
Thomas Gleixner 已提交
4367

4368
	return ret;
T
Thomas Gleixner 已提交
4369 4370 4371 4372 4373
}

static ssize_t
perf_read(struct file *file, char __user *buf, size_t count, loff_t *ppos)
{
4374
	struct perf_event *event = file->private_data;
P
Peter Zijlstra 已提交
4375 4376
	struct perf_event_context *ctx;
	int ret;
T
Thomas Gleixner 已提交
4377

P
Peter Zijlstra 已提交
4378
	ctx = perf_event_ctx_lock(event);
4379
	ret = __perf_read(event, buf, count);
P
Peter Zijlstra 已提交
4380 4381 4382
	perf_event_ctx_unlock(event, ctx);

	return ret;
T
Thomas Gleixner 已提交
4383 4384 4385 4386
}

static unsigned int perf_poll(struct file *file, poll_table *wait)
{
4387
	struct perf_event *event = file->private_data;
4388
	struct ring_buffer *rb;
4389
	unsigned int events = POLLHUP;
P
Peter Zijlstra 已提交
4390

4391
	poll_wait(file, &event->waitq, wait);
4392

4393
	if (is_event_hup(event))
4394
		return events;
P
Peter Zijlstra 已提交
4395

4396
	/*
4397 4398
	 * Pin the event->rb by taking event->mmap_mutex; otherwise
	 * perf_event_set_output() can swizzle our rb and make us miss wakeups.
4399 4400
	 */
	mutex_lock(&event->mmap_mutex);
4401 4402
	rb = event->rb;
	if (rb)
4403
		events = atomic_xchg(&rb->poll, 0);
4404
	mutex_unlock(&event->mmap_mutex);
T
Thomas Gleixner 已提交
4405 4406 4407
	return events;
}

P
Peter Zijlstra 已提交
4408
static void _perf_event_reset(struct perf_event *event)
4409
{
4410
	(void)perf_event_read(event, false);
4411
	local64_set(&event->count, 0);
4412
	perf_event_update_userpage(event);
P
Peter Zijlstra 已提交
4413 4414
}

4415
/*
4416 4417
 * Holding the top-level event's child_mutex means that any
 * descendant process that has inherited this event will block
4418
 * in perf_event_exit_event() if it goes to exit, thus satisfying the
4419
 * task existence requirements of perf_event_enable/disable.
4420
 */
4421 4422
static void perf_event_for_each_child(struct perf_event *event,
					void (*func)(struct perf_event *))
P
Peter Zijlstra 已提交
4423
{
4424
	struct perf_event *child;
P
Peter Zijlstra 已提交
4425

4426
	WARN_ON_ONCE(event->ctx->parent_ctx);
P
Peter Zijlstra 已提交
4427

4428 4429 4430
	mutex_lock(&event->child_mutex);
	func(event);
	list_for_each_entry(child, &event->child_list, child_list)
P
Peter Zijlstra 已提交
4431
		func(child);
4432
	mutex_unlock(&event->child_mutex);
P
Peter Zijlstra 已提交
4433 4434
}

4435 4436
static void perf_event_for_each(struct perf_event *event,
				  void (*func)(struct perf_event *))
P
Peter Zijlstra 已提交
4437
{
4438 4439
	struct perf_event_context *ctx = event->ctx;
	struct perf_event *sibling;
P
Peter Zijlstra 已提交
4440

P
Peter Zijlstra 已提交
4441 4442
	lockdep_assert_held(&ctx->mutex);

4443
	event = event->group_leader;
4444

4445 4446
	perf_event_for_each_child(event, func);
	list_for_each_entry(sibling, &event->sibling_list, group_entry)
4447
		perf_event_for_each_child(sibling, func);
4448 4449
}

4450 4451 4452 4453
static void __perf_event_period(struct perf_event *event,
				struct perf_cpu_context *cpuctx,
				struct perf_event_context *ctx,
				void *info)
4454
{
4455
	u64 value = *((u64 *)info);
4456
	bool active;
4457

4458 4459
	if (event->attr.freq) {
		event->attr.sample_freq = value;
4460
	} else {
4461 4462
		event->attr.sample_period = value;
		event->hw.sample_period = value;
4463
	}
4464 4465 4466 4467

	active = (event->state == PERF_EVENT_STATE_ACTIVE);
	if (active) {
		perf_pmu_disable(ctx->pmu);
4468 4469 4470 4471 4472 4473 4474 4475
		/*
		 * We could be throttled; unthrottle now to avoid the tick
		 * trying to unthrottle while we already re-started the event.
		 */
		if (event->hw.interrupts == MAX_INTERRUPTS) {
			event->hw.interrupts = 0;
			perf_log_throttle(event, 1);
		}
4476 4477 4478 4479 4480 4481 4482 4483 4484
		event->pmu->stop(event, PERF_EF_UPDATE);
	}

	local64_set(&event->hw.period_left, 0);

	if (active) {
		event->pmu->start(event, PERF_EF_RELOAD);
		perf_pmu_enable(ctx->pmu);
	}
4485 4486 4487 4488 4489 4490 4491 4492 4493 4494 4495 4496 4497 4498 4499 4500 4501 4502
}

static int perf_event_period(struct perf_event *event, u64 __user *arg)
{
	u64 value;

	if (!is_sampling_event(event))
		return -EINVAL;

	if (copy_from_user(&value, arg, sizeof(value)))
		return -EFAULT;

	if (!value)
		return -EINVAL;

	if (event->attr.freq && value > sysctl_perf_event_sample_rate)
		return -EINVAL;

4503
	event_function_call(event, __perf_event_period, &value);
4504

4505
	return 0;
4506 4507
}

4508 4509
static const struct file_operations perf_fops;

4510
static inline int perf_fget_light(int fd, struct fd *p)
4511
{
4512 4513 4514
	struct fd f = fdget(fd);
	if (!f.file)
		return -EBADF;
4515

4516 4517 4518
	if (f.file->f_op != &perf_fops) {
		fdput(f);
		return -EBADF;
4519
	}
4520 4521
	*p = f;
	return 0;
4522 4523 4524 4525
}

static int perf_event_set_output(struct perf_event *event,
				 struct perf_event *output_event);
L
Li Zefan 已提交
4526
static int perf_event_set_filter(struct perf_event *event, void __user *arg);
4527
static int perf_event_set_bpf_prog(struct perf_event *event, u32 prog_fd);
4528

P
Peter Zijlstra 已提交
4529
static long _perf_ioctl(struct perf_event *event, unsigned int cmd, unsigned long arg)
4530
{
4531
	void (*func)(struct perf_event *);
P
Peter Zijlstra 已提交
4532
	u32 flags = arg;
4533 4534

	switch (cmd) {
4535
	case PERF_EVENT_IOC_ENABLE:
P
Peter Zijlstra 已提交
4536
		func = _perf_event_enable;
4537
		break;
4538
	case PERF_EVENT_IOC_DISABLE:
P
Peter Zijlstra 已提交
4539
		func = _perf_event_disable;
4540
		break;
4541
	case PERF_EVENT_IOC_RESET:
P
Peter Zijlstra 已提交
4542
		func = _perf_event_reset;
4543
		break;
P
Peter Zijlstra 已提交
4544

4545
	case PERF_EVENT_IOC_REFRESH:
P
Peter Zijlstra 已提交
4546
		return _perf_event_refresh(event, arg);
4547

4548 4549
	case PERF_EVENT_IOC_PERIOD:
		return perf_event_period(event, (u64 __user *)arg);
4550

4551 4552 4553 4554 4555 4556 4557 4558 4559
	case PERF_EVENT_IOC_ID:
	{
		u64 id = primary_event_id(event);

		if (copy_to_user((void __user *)arg, &id, sizeof(id)))
			return -EFAULT;
		return 0;
	}

4560
	case PERF_EVENT_IOC_SET_OUTPUT:
4561 4562 4563
	{
		int ret;
		if (arg != -1) {
4564 4565 4566 4567 4568 4569 4570 4571 4572 4573
			struct perf_event *output_event;
			struct fd output;
			ret = perf_fget_light(arg, &output);
			if (ret)
				return ret;
			output_event = output.file->private_data;
			ret = perf_event_set_output(event, output_event);
			fdput(output);
		} else {
			ret = perf_event_set_output(event, NULL);
4574 4575 4576
		}
		return ret;
	}
4577

L
Li Zefan 已提交
4578 4579 4580
	case PERF_EVENT_IOC_SET_FILTER:
		return perf_event_set_filter(event, (void __user *)arg);

4581 4582 4583
	case PERF_EVENT_IOC_SET_BPF:
		return perf_event_set_bpf_prog(event, arg);

4584 4585 4586 4587 4588 4589 4590 4591 4592 4593 4594 4595 4596
	case PERF_EVENT_IOC_PAUSE_OUTPUT: {
		struct ring_buffer *rb;

		rcu_read_lock();
		rb = rcu_dereference(event->rb);
		if (!rb || !rb->nr_pages) {
			rcu_read_unlock();
			return -EINVAL;
		}
		rb_toggle_paused(rb, !!arg);
		rcu_read_unlock();
		return 0;
	}
4597
	default:
P
Peter Zijlstra 已提交
4598
		return -ENOTTY;
4599
	}
P
Peter Zijlstra 已提交
4600 4601

	if (flags & PERF_IOC_FLAG_GROUP)
4602
		perf_event_for_each(event, func);
P
Peter Zijlstra 已提交
4603
	else
4604
		perf_event_for_each_child(event, func);
P
Peter Zijlstra 已提交
4605 4606

	return 0;
4607 4608
}

P
Peter Zijlstra 已提交
4609 4610 4611 4612 4613 4614 4615 4616 4617 4618 4619 4620 4621
static long perf_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
{
	struct perf_event *event = file->private_data;
	struct perf_event_context *ctx;
	long ret;

	ctx = perf_event_ctx_lock(event);
	ret = _perf_ioctl(event, cmd, arg);
	perf_event_ctx_unlock(event, ctx);

	return ret;
}

P
Pawel Moll 已提交
4622 4623 4624 4625 4626 4627 4628 4629 4630 4631 4632 4633 4634 4635 4636 4637 4638 4639 4640 4641
#ifdef CONFIG_COMPAT
static long perf_compat_ioctl(struct file *file, unsigned int cmd,
				unsigned long arg)
{
	switch (_IOC_NR(cmd)) {
	case _IOC_NR(PERF_EVENT_IOC_SET_FILTER):
	case _IOC_NR(PERF_EVENT_IOC_ID):
		/* Fix up pointer size (usually 4 -> 8 in 32-on-64-bit case */
		if (_IOC_SIZE(cmd) == sizeof(compat_uptr_t)) {
			cmd &= ~IOCSIZE_MASK;
			cmd |= sizeof(void *) << IOCSIZE_SHIFT;
		}
		break;
	}
	return perf_ioctl(file, cmd, arg);
}
#else
# define perf_compat_ioctl NULL
#endif

4642
int perf_event_task_enable(void)
4643
{
P
Peter Zijlstra 已提交
4644
	struct perf_event_context *ctx;
4645
	struct perf_event *event;
4646

4647
	mutex_lock(&current->perf_event_mutex);
P
Peter Zijlstra 已提交
4648 4649 4650 4651 4652
	list_for_each_entry(event, &current->perf_event_list, owner_entry) {
		ctx = perf_event_ctx_lock(event);
		perf_event_for_each_child(event, _perf_event_enable);
		perf_event_ctx_unlock(event, ctx);
	}
4653
	mutex_unlock(&current->perf_event_mutex);
4654 4655 4656 4657

	return 0;
}

4658
int perf_event_task_disable(void)
4659
{
P
Peter Zijlstra 已提交
4660
	struct perf_event_context *ctx;
4661
	struct perf_event *event;
4662

4663
	mutex_lock(&current->perf_event_mutex);
P
Peter Zijlstra 已提交
4664 4665 4666 4667 4668
	list_for_each_entry(event, &current->perf_event_list, owner_entry) {
		ctx = perf_event_ctx_lock(event);
		perf_event_for_each_child(event, _perf_event_disable);
		perf_event_ctx_unlock(event, ctx);
	}
4669
	mutex_unlock(&current->perf_event_mutex);
4670 4671 4672 4673

	return 0;
}

4674
static int perf_event_index(struct perf_event *event)
4675
{
P
Peter Zijlstra 已提交
4676 4677 4678
	if (event->hw.state & PERF_HES_STOPPED)
		return 0;

4679
	if (event->state != PERF_EVENT_STATE_ACTIVE)
4680 4681
		return 0;

4682
	return event->pmu->event_idx(event);
4683 4684
}

4685
static void calc_timer_values(struct perf_event *event,
4686
				u64 *now,
4687 4688
				u64 *enabled,
				u64 *running)
4689
{
4690
	u64 ctx_time;
4691

4692 4693
	*now = perf_clock();
	ctx_time = event->shadow_ctx_time + *now;
4694 4695 4696 4697
	*enabled = ctx_time - event->tstamp_enabled;
	*running = ctx_time - event->tstamp_running;
}

4698 4699 4700 4701 4702 4703 4704 4705 4706 4707 4708 4709 4710 4711 4712
static void perf_event_init_userpage(struct perf_event *event)
{
	struct perf_event_mmap_page *userpg;
	struct ring_buffer *rb;

	rcu_read_lock();
	rb = rcu_dereference(event->rb);
	if (!rb)
		goto unlock;

	userpg = rb->user_page;

	/* Allow new userspace to detect that bit 0 is deprecated */
	userpg->cap_bit0_is_deprecated = 1;
	userpg->size = offsetof(struct perf_event_mmap_page, __reserved);
4713 4714
	userpg->data_offset = PAGE_SIZE;
	userpg->data_size = perf_data_size(rb);
4715 4716 4717 4718 4719

unlock:
	rcu_read_unlock();
}

4720 4721
void __weak arch_perf_update_userpage(
	struct perf_event *event, struct perf_event_mmap_page *userpg, u64 now)
4722 4723 4724
{
}

4725 4726 4727 4728 4729
/*
 * Callers need to ensure there can be no nesting of this function, otherwise
 * the seqlock logic goes bad. We can not serialize this because the arch
 * code calls this from NMI context.
 */
4730
void perf_event_update_userpage(struct perf_event *event)
4731
{
4732
	struct perf_event_mmap_page *userpg;
4733
	struct ring_buffer *rb;
4734
	u64 enabled, running, now;
4735 4736

	rcu_read_lock();
4737 4738 4739 4740
	rb = rcu_dereference(event->rb);
	if (!rb)
		goto unlock;

4741 4742 4743 4744 4745 4746 4747 4748 4749
	/*
	 * compute total_time_enabled, total_time_running
	 * based on snapshot values taken when the event
	 * was last scheduled in.
	 *
	 * we cannot simply called update_context_time()
	 * because of locking issue as we can be called in
	 * NMI context
	 */
4750
	calc_timer_values(event, &now, &enabled, &running);
4751

4752
	userpg = rb->user_page;
4753 4754 4755 4756 4757
	/*
	 * Disable preemption so as to not let the corresponding user-space
	 * spin too long if we get preempted.
	 */
	preempt_disable();
4758
	++userpg->lock;
4759
	barrier();
4760
	userpg->index = perf_event_index(event);
P
Peter Zijlstra 已提交
4761
	userpg->offset = perf_event_count(event);
4762
	if (userpg->index)
4763
		userpg->offset -= local64_read(&event->hw.prev_count);
4764

4765
	userpg->time_enabled = enabled +
4766
			atomic64_read(&event->child_total_time_enabled);
4767

4768
	userpg->time_running = running +
4769
			atomic64_read(&event->child_total_time_running);
4770

4771
	arch_perf_update_userpage(event, userpg, now);
4772

4773
	barrier();
4774
	++userpg->lock;
4775
	preempt_enable();
4776
unlock:
4777
	rcu_read_unlock();
4778 4779
}

4780 4781 4782
static int perf_mmap_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
{
	struct perf_event *event = vma->vm_file->private_data;
4783
	struct ring_buffer *rb;
4784 4785 4786 4787 4788 4789 4790 4791 4792
	int ret = VM_FAULT_SIGBUS;

	if (vmf->flags & FAULT_FLAG_MKWRITE) {
		if (vmf->pgoff == 0)
			ret = 0;
		return ret;
	}

	rcu_read_lock();
4793 4794
	rb = rcu_dereference(event->rb);
	if (!rb)
4795 4796 4797 4798 4799
		goto unlock;

	if (vmf->pgoff && (vmf->flags & FAULT_FLAG_WRITE))
		goto unlock;

4800
	vmf->page = perf_mmap_to_page(rb, vmf->pgoff);
4801 4802 4803 4804 4805 4806 4807 4808 4809 4810 4811 4812 4813 4814
	if (!vmf->page)
		goto unlock;

	get_page(vmf->page);
	vmf->page->mapping = vma->vm_file->f_mapping;
	vmf->page->index   = vmf->pgoff;

	ret = 0;
unlock:
	rcu_read_unlock();

	return ret;
}

4815 4816 4817
static void ring_buffer_attach(struct perf_event *event,
			       struct ring_buffer *rb)
{
4818
	struct ring_buffer *old_rb = NULL;
4819 4820
	unsigned long flags;

4821 4822 4823 4824 4825 4826
	if (event->rb) {
		/*
		 * Should be impossible, we set this when removing
		 * event->rb_entry and wait/clear when adding event->rb_entry.
		 */
		WARN_ON_ONCE(event->rcu_pending);
4827

4828 4829 4830 4831
		old_rb = event->rb;
		spin_lock_irqsave(&old_rb->event_lock, flags);
		list_del_rcu(&event->rb_entry);
		spin_unlock_irqrestore(&old_rb->event_lock, flags);
4832

4833 4834
		event->rcu_batches = get_state_synchronize_rcu();
		event->rcu_pending = 1;
4835
	}
4836

4837
	if (rb) {
4838 4839 4840 4841 4842
		if (event->rcu_pending) {
			cond_synchronize_rcu(event->rcu_batches);
			event->rcu_pending = 0;
		}

4843 4844 4845 4846 4847 4848 4849 4850 4851 4852 4853 4854 4855 4856 4857 4858
		spin_lock_irqsave(&rb->event_lock, flags);
		list_add_rcu(&event->rb_entry, &rb->event_list);
		spin_unlock_irqrestore(&rb->event_lock, flags);
	}

	rcu_assign_pointer(event->rb, rb);

	if (old_rb) {
		ring_buffer_put(old_rb);
		/*
		 * Since we detached before setting the new rb, so that we
		 * could attach the new rb, we could have missed a wakeup.
		 * Provide it now.
		 */
		wake_up_all(&event->waitq);
	}
4859 4860 4861 4862 4863 4864 4865 4866
}

static void ring_buffer_wakeup(struct perf_event *event)
{
	struct ring_buffer *rb;

	rcu_read_lock();
	rb = rcu_dereference(event->rb);
4867 4868 4869 4870
	if (rb) {
		list_for_each_entry_rcu(event, &rb->event_list, rb_entry)
			wake_up_all(&event->waitq);
	}
4871 4872 4873
	rcu_read_unlock();
}

4874
struct ring_buffer *ring_buffer_get(struct perf_event *event)
4875
{
4876
	struct ring_buffer *rb;
4877

4878
	rcu_read_lock();
4879 4880 4881 4882
	rb = rcu_dereference(event->rb);
	if (rb) {
		if (!atomic_inc_not_zero(&rb->refcount))
			rb = NULL;
4883 4884 4885
	}
	rcu_read_unlock();

4886
	return rb;
4887 4888
}

4889
void ring_buffer_put(struct ring_buffer *rb)
4890
{
4891
	if (!atomic_dec_and_test(&rb->refcount))
4892
		return;
4893

4894
	WARN_ON_ONCE(!list_empty(&rb->event_list));
4895

4896
	call_rcu(&rb->rcu_head, rb_free_rcu);
4897 4898 4899 4900
}

static void perf_mmap_open(struct vm_area_struct *vma)
{
4901
	struct perf_event *event = vma->vm_file->private_data;
4902

4903
	atomic_inc(&event->mmap_count);
4904
	atomic_inc(&event->rb->mmap_count);
4905

4906 4907 4908
	if (vma->vm_pgoff)
		atomic_inc(&event->rb->aux_mmap_count);

4909 4910
	if (event->pmu->event_mapped)
		event->pmu->event_mapped(event);
4911 4912
}

4913 4914
static void perf_pmu_output_stop(struct perf_event *event);

4915 4916 4917 4918 4919 4920 4921 4922
/*
 * A buffer can be mmap()ed multiple times; either directly through the same
 * event, or through other events by use of perf_event_set_output().
 *
 * In order to undo the VM accounting done by perf_mmap() we need to destroy
 * the buffer here, where we still have a VM context. This means we need
 * to detach all events redirecting to us.
 */
4923 4924
static void perf_mmap_close(struct vm_area_struct *vma)
{
4925
	struct perf_event *event = vma->vm_file->private_data;
4926

4927
	struct ring_buffer *rb = ring_buffer_get(event);
4928 4929 4930
	struct user_struct *mmap_user = rb->mmap_user;
	int mmap_locked = rb->mmap_locked;
	unsigned long size = perf_data_size(rb);
4931

4932 4933 4934
	if (event->pmu->event_unmapped)
		event->pmu->event_unmapped(event);

4935 4936 4937 4938 4939 4940 4941
	/*
	 * rb->aux_mmap_count will always drop before rb->mmap_count and
	 * event->mmap_count, so it is ok to use event->mmap_mutex to
	 * serialize with perf_mmap here.
	 */
	if (rb_has_aux(rb) && vma->vm_pgoff == rb->aux_pgoff &&
	    atomic_dec_and_mutex_lock(&rb->aux_mmap_count, &event->mmap_mutex)) {
4942 4943 4944 4945 4946 4947 4948 4949 4950
		/*
		 * Stop all AUX events that are writing to this buffer,
		 * so that we can free its AUX pages and corresponding PMU
		 * data. Note that after rb::aux_mmap_count dropped to zero,
		 * they won't start any more (see perf_aux_output_begin()).
		 */
		perf_pmu_output_stop(event);

		/* now it's safe to free the pages */
4951 4952 4953
		atomic_long_sub(rb->aux_nr_pages, &mmap_user->locked_vm);
		vma->vm_mm->pinned_vm -= rb->aux_mmap_locked;

4954
		/* this has to be the last one */
4955
		rb_free_aux(rb);
4956 4957
		WARN_ON_ONCE(atomic_read(&rb->aux_refcount));

4958 4959 4960
		mutex_unlock(&event->mmap_mutex);
	}

4961 4962 4963
	atomic_dec(&rb->mmap_count);

	if (!atomic_dec_and_mutex_lock(&event->mmap_count, &event->mmap_mutex))
4964
		goto out_put;
4965

4966
	ring_buffer_attach(event, NULL);
4967 4968 4969
	mutex_unlock(&event->mmap_mutex);

	/* If there's still other mmap()s of this buffer, we're done. */
4970 4971
	if (atomic_read(&rb->mmap_count))
		goto out_put;
4972

4973 4974 4975 4976 4977 4978 4979 4980 4981 4982 4983 4984 4985 4986 4987 4988
	/*
	 * No other mmap()s, detach from all other events that might redirect
	 * into the now unreachable buffer. Somewhat complicated by the
	 * fact that rb::event_lock otherwise nests inside mmap_mutex.
	 */
again:
	rcu_read_lock();
	list_for_each_entry_rcu(event, &rb->event_list, rb_entry) {
		if (!atomic_long_inc_not_zero(&event->refcount)) {
			/*
			 * This event is en-route to free_event() which will
			 * detach it and remove it from the list.
			 */
			continue;
		}
		rcu_read_unlock();
4989

4990 4991 4992 4993 4994 4995 4996 4997 4998 4999 5000
		mutex_lock(&event->mmap_mutex);
		/*
		 * Check we didn't race with perf_event_set_output() which can
		 * swizzle the rb from under us while we were waiting to
		 * acquire mmap_mutex.
		 *
		 * If we find a different rb; ignore this event, a next
		 * iteration will no longer find it on the list. We have to
		 * still restart the iteration to make sure we're not now
		 * iterating the wrong list.
		 */
5001 5002 5003
		if (event->rb == rb)
			ring_buffer_attach(event, NULL);

5004
		mutex_unlock(&event->mmap_mutex);
5005
		put_event(event);
5006

5007 5008 5009 5010 5011
		/*
		 * Restart the iteration; either we're on the wrong list or
		 * destroyed its integrity by doing a deletion.
		 */
		goto again;
5012
	}
5013 5014 5015 5016 5017 5018 5019 5020 5021 5022 5023 5024 5025 5026 5027
	rcu_read_unlock();

	/*
	 * It could be there's still a few 0-ref events on the list; they'll
	 * get cleaned up by free_event() -- they'll also still have their
	 * ref on the rb and will free it whenever they are done with it.
	 *
	 * Aside from that, this buffer is 'fully' detached and unmapped,
	 * undo the VM accounting.
	 */

	atomic_long_sub((size >> PAGE_SHIFT) + 1, &mmap_user->locked_vm);
	vma->vm_mm->pinned_vm -= mmap_locked;
	free_uid(mmap_user);

5028
out_put:
5029
	ring_buffer_put(rb); /* could be last */
5030 5031
}

5032
static const struct vm_operations_struct perf_mmap_vmops = {
5033
	.open		= perf_mmap_open,
5034
	.close		= perf_mmap_close, /* non mergable */
5035 5036
	.fault		= perf_mmap_fault,
	.page_mkwrite	= perf_mmap_fault,
5037 5038 5039 5040
};

static int perf_mmap(struct file *file, struct vm_area_struct *vma)
{
5041
	struct perf_event *event = file->private_data;
5042
	unsigned long user_locked, user_lock_limit;
5043
	struct user_struct *user = current_user();
5044
	unsigned long locked, lock_limit;
5045
	struct ring_buffer *rb = NULL;
5046 5047
	unsigned long vma_size;
	unsigned long nr_pages;
5048
	long user_extra = 0, extra = 0;
5049
	int ret = 0, flags = 0;
5050

5051 5052 5053
	/*
	 * Don't allow mmap() of inherited per-task counters. This would
	 * create a performance issue due to all children writing to the
5054
	 * same rb.
5055 5056 5057 5058
	 */
	if (event->cpu == -1 && event->attr.inherit)
		return -EINVAL;

5059
	if (!(vma->vm_flags & VM_SHARED))
5060
		return -EINVAL;
5061 5062

	vma_size = vma->vm_end - vma->vm_start;
5063 5064 5065 5066 5067 5068 5069 5070 5071 5072 5073 5074 5075 5076 5077 5078 5079 5080 5081 5082 5083 5084 5085 5086 5087 5088 5089 5090 5091 5092 5093 5094 5095 5096 5097 5098 5099 5100 5101 5102 5103 5104 5105 5106 5107 5108 5109 5110 5111 5112 5113 5114 5115 5116 5117 5118 5119 5120 5121 5122

	if (vma->vm_pgoff == 0) {
		nr_pages = (vma_size / PAGE_SIZE) - 1;
	} else {
		/*
		 * AUX area mapping: if rb->aux_nr_pages != 0, it's already
		 * mapped, all subsequent mappings should have the same size
		 * and offset. Must be above the normal perf buffer.
		 */
		u64 aux_offset, aux_size;

		if (!event->rb)
			return -EINVAL;

		nr_pages = vma_size / PAGE_SIZE;

		mutex_lock(&event->mmap_mutex);
		ret = -EINVAL;

		rb = event->rb;
		if (!rb)
			goto aux_unlock;

		aux_offset = ACCESS_ONCE(rb->user_page->aux_offset);
		aux_size = ACCESS_ONCE(rb->user_page->aux_size);

		if (aux_offset < perf_data_size(rb) + PAGE_SIZE)
			goto aux_unlock;

		if (aux_offset != vma->vm_pgoff << PAGE_SHIFT)
			goto aux_unlock;

		/* already mapped with a different offset */
		if (rb_has_aux(rb) && rb->aux_pgoff != vma->vm_pgoff)
			goto aux_unlock;

		if (aux_size != vma_size || aux_size != nr_pages * PAGE_SIZE)
			goto aux_unlock;

		/* already mapped with a different size */
		if (rb_has_aux(rb) && rb->aux_nr_pages != nr_pages)
			goto aux_unlock;

		if (!is_power_of_2(nr_pages))
			goto aux_unlock;

		if (!atomic_inc_not_zero(&rb->mmap_count))
			goto aux_unlock;

		if (rb_has_aux(rb)) {
			atomic_inc(&rb->aux_mmap_count);
			ret = 0;
			goto unlock;
		}

		atomic_set(&rb->aux_mmap_count, 1);
		user_extra = nr_pages;

		goto accounting;
	}
5123

5124
	/*
5125
	 * If we have rb pages ensure they're a power-of-two number, so we
5126 5127
	 * can do bitmasks instead of modulo.
	 */
5128
	if (nr_pages != 0 && !is_power_of_2(nr_pages))
5129 5130
		return -EINVAL;

5131
	if (vma_size != PAGE_SIZE * (1 + nr_pages))
5132 5133
		return -EINVAL;

5134
	WARN_ON_ONCE(event->ctx->parent_ctx);
5135
again:
5136
	mutex_lock(&event->mmap_mutex);
5137
	if (event->rb) {
5138
		if (event->rb->nr_pages != nr_pages) {
5139
			ret = -EINVAL;
5140 5141 5142 5143 5144 5145 5146 5147 5148 5149 5150 5151 5152
			goto unlock;
		}

		if (!atomic_inc_not_zero(&event->rb->mmap_count)) {
			/*
			 * Raced against perf_mmap_close() through
			 * perf_event_set_output(). Try again, hope for better
			 * luck.
			 */
			mutex_unlock(&event->mmap_mutex);
			goto again;
		}

5153 5154 5155
		goto unlock;
	}

5156
	user_extra = nr_pages + 1;
5157 5158

accounting:
5159
	user_lock_limit = sysctl_perf_event_mlock >> (PAGE_SHIFT - 10);
I
Ingo Molnar 已提交
5160 5161 5162 5163 5164 5165

	/*
	 * Increase the limit linearly with more CPUs:
	 */
	user_lock_limit *= num_online_cpus();

5166
	user_locked = atomic_long_read(&user->locked_vm) + user_extra;
5167

5168 5169
	if (user_locked > user_lock_limit)
		extra = user_locked - user_lock_limit;
5170

5171
	lock_limit = rlimit(RLIMIT_MEMLOCK);
5172
	lock_limit >>= PAGE_SHIFT;
5173
	locked = vma->vm_mm->pinned_vm + extra;
5174

5175 5176
	if ((locked > lock_limit) && perf_paranoid_tracepoint_raw() &&
		!capable(CAP_IPC_LOCK)) {
5177 5178 5179
		ret = -EPERM;
		goto unlock;
	}
5180

5181
	WARN_ON(!rb && event->rb);
5182

5183
	if (vma->vm_flags & VM_WRITE)
5184
		flags |= RING_BUFFER_WRITABLE;
5185

5186
	if (!rb) {
5187 5188 5189
		rb = rb_alloc(nr_pages,
			      event->attr.watermark ? event->attr.wakeup_watermark : 0,
			      event->cpu, flags);
P
Peter Zijlstra 已提交
5190

5191 5192 5193 5194
		if (!rb) {
			ret = -ENOMEM;
			goto unlock;
		}
5195

5196 5197 5198
		atomic_set(&rb->mmap_count, 1);
		rb->mmap_user = get_current_user();
		rb->mmap_locked = extra;
P
Peter Zijlstra 已提交
5199

5200
		ring_buffer_attach(event, rb);
5201

5202 5203 5204
		perf_event_init_userpage(event);
		perf_event_update_userpage(event);
	} else {
5205 5206
		ret = rb_alloc_aux(rb, event, vma->vm_pgoff, nr_pages,
				   event->attr.aux_watermark, flags);
5207 5208 5209
		if (!ret)
			rb->aux_mmap_locked = extra;
	}
5210

5211
unlock:
5212 5213 5214 5215
	if (!ret) {
		atomic_long_add(user_extra, &user->locked_vm);
		vma->vm_mm->pinned_vm += extra;

5216
		atomic_inc(&event->mmap_count);
5217 5218 5219 5220
	} else if (rb) {
		atomic_dec(&rb->mmap_count);
	}
aux_unlock:
5221
	mutex_unlock(&event->mmap_mutex);
5222

5223 5224 5225 5226
	/*
	 * Since pinned accounting is per vm we cannot allow fork() to copy our
	 * vma.
	 */
P
Peter Zijlstra 已提交
5227
	vma->vm_flags |= VM_DONTCOPY | VM_DONTEXPAND | VM_DONTDUMP;
5228
	vma->vm_ops = &perf_mmap_vmops;
5229

5230 5231 5232
	if (event->pmu->event_mapped)
		event->pmu->event_mapped(event);

5233
	return ret;
5234 5235
}

P
Peter Zijlstra 已提交
5236 5237
static int perf_fasync(int fd, struct file *filp, int on)
{
A
Al Viro 已提交
5238
	struct inode *inode = file_inode(filp);
5239
	struct perf_event *event = filp->private_data;
P
Peter Zijlstra 已提交
5240 5241
	int retval;

A
Al Viro 已提交
5242
	inode_lock(inode);
5243
	retval = fasync_helper(fd, filp, on, &event->fasync);
A
Al Viro 已提交
5244
	inode_unlock(inode);
P
Peter Zijlstra 已提交
5245 5246 5247 5248 5249 5250 5251

	if (retval < 0)
		return retval;

	return 0;
}

T
Thomas Gleixner 已提交
5252
static const struct file_operations perf_fops = {
5253
	.llseek			= no_llseek,
T
Thomas Gleixner 已提交
5254 5255 5256
	.release		= perf_release,
	.read			= perf_read,
	.poll			= perf_poll,
5257
	.unlocked_ioctl		= perf_ioctl,
P
Pawel Moll 已提交
5258
	.compat_ioctl		= perf_compat_ioctl,
5259
	.mmap			= perf_mmap,
P
Peter Zijlstra 已提交
5260
	.fasync			= perf_fasync,
T
Thomas Gleixner 已提交
5261 5262
};

5263
/*
5264
 * Perf event wakeup
5265 5266 5267 5268 5269
 *
 * If there's data, ensure we set the poll() state and publish everything
 * to user-space before waking everybody up.
 */

5270 5271 5272 5273 5274 5275 5276 5277
static inline struct fasync_struct **perf_event_fasync(struct perf_event *event)
{
	/* only the parent has fasync state */
	if (event->parent)
		event = event->parent;
	return &event->fasync;
}

5278
void perf_event_wakeup(struct perf_event *event)
5279
{
5280
	ring_buffer_wakeup(event);
5281

5282
	if (event->pending_kill) {
5283
		kill_fasync(perf_event_fasync(event), SIGIO, event->pending_kill);
5284
		event->pending_kill = 0;
5285
	}
5286 5287
}

5288
static void perf_pending_event(struct irq_work *entry)
5289
{
5290 5291
	struct perf_event *event = container_of(entry,
			struct perf_event, pending);
5292 5293 5294 5295 5296 5297 5298
	int rctx;

	rctx = perf_swevent_get_recursion_context();
	/*
	 * If we 'fail' here, that's OK, it means recursion is already disabled
	 * and we won't recurse 'further'.
	 */
5299

5300 5301
	if (event->pending_disable) {
		event->pending_disable = 0;
5302
		perf_event_disable_local(event);
5303 5304
	}

5305 5306 5307
	if (event->pending_wakeup) {
		event->pending_wakeup = 0;
		perf_event_wakeup(event);
5308
	}
5309 5310 5311

	if (rctx >= 0)
		perf_swevent_put_recursion_context(rctx);
5312 5313
}

5314 5315 5316 5317 5318 5319 5320 5321 5322 5323 5324 5325 5326 5327 5328 5329 5330 5331 5332 5333 5334
/*
 * We assume there is only KVM supporting the callbacks.
 * Later on, we might change it to a list if there is
 * another virtualization implementation supporting the callbacks.
 */
struct perf_guest_info_callbacks *perf_guest_cbs;

int perf_register_guest_info_callbacks(struct perf_guest_info_callbacks *cbs)
{
	perf_guest_cbs = cbs;
	return 0;
}
EXPORT_SYMBOL_GPL(perf_register_guest_info_callbacks);

int perf_unregister_guest_info_callbacks(struct perf_guest_info_callbacks *cbs)
{
	perf_guest_cbs = NULL;
	return 0;
}
EXPORT_SYMBOL_GPL(perf_unregister_guest_info_callbacks);

5335 5336 5337 5338 5339
static void
perf_output_sample_regs(struct perf_output_handle *handle,
			struct pt_regs *regs, u64 mask)
{
	int bit;
5340
	DECLARE_BITMAP(_mask, 64);
5341

5342 5343
	bitmap_from_u64(_mask, mask);
	for_each_set_bit(bit, _mask, sizeof(mask) * BITS_PER_BYTE) {
5344 5345 5346 5347 5348 5349 5350
		u64 val;

		val = perf_reg_value(regs, bit);
		perf_output_put(handle, val);
	}
}

5351
static void perf_sample_regs_user(struct perf_regs *regs_user,
5352 5353
				  struct pt_regs *regs,
				  struct pt_regs *regs_user_copy)
5354
{
5355 5356
	if (user_mode(regs)) {
		regs_user->abi = perf_reg_abi(current);
5357
		regs_user->regs = regs;
5358 5359
	} else if (current->mm) {
		perf_get_regs_user(regs_user, regs, regs_user_copy);
5360 5361 5362
	} else {
		regs_user->abi = PERF_SAMPLE_REGS_ABI_NONE;
		regs_user->regs = NULL;
5363 5364 5365
	}
}

5366 5367 5368 5369 5370 5371 5372 5373
static void perf_sample_regs_intr(struct perf_regs *regs_intr,
				  struct pt_regs *regs)
{
	regs_intr->regs = regs;
	regs_intr->abi  = perf_reg_abi(current);
}


5374 5375 5376 5377 5378 5379 5380 5381 5382 5383 5384 5385 5386 5387 5388 5389 5390 5391 5392 5393 5394 5395 5396 5397 5398 5399 5400 5401 5402 5403 5404 5405 5406 5407 5408 5409 5410 5411 5412 5413 5414 5415 5416 5417 5418 5419 5420 5421 5422 5423 5424 5425 5426 5427 5428 5429 5430 5431 5432 5433 5434 5435 5436 5437 5438 5439 5440 5441 5442 5443 5444 5445 5446 5447 5448 5449 5450 5451 5452 5453 5454 5455 5456 5457 5458 5459 5460 5461 5462 5463 5464 5465 5466 5467 5468
/*
 * Get remaining task size from user stack pointer.
 *
 * It'd be better to take stack vma map and limit this more
 * precisly, but there's no way to get it safely under interrupt,
 * so using TASK_SIZE as limit.
 */
static u64 perf_ustack_task_size(struct pt_regs *regs)
{
	unsigned long addr = perf_user_stack_pointer(regs);

	if (!addr || addr >= TASK_SIZE)
		return 0;

	return TASK_SIZE - addr;
}

static u16
perf_sample_ustack_size(u16 stack_size, u16 header_size,
			struct pt_regs *regs)
{
	u64 task_size;

	/* No regs, no stack pointer, no dump. */
	if (!regs)
		return 0;

	/*
	 * Check if we fit in with the requested stack size into the:
	 * - TASK_SIZE
	 *   If we don't, we limit the size to the TASK_SIZE.
	 *
	 * - remaining sample size
	 *   If we don't, we customize the stack size to
	 *   fit in to the remaining sample size.
	 */

	task_size  = min((u64) USHRT_MAX, perf_ustack_task_size(regs));
	stack_size = min(stack_size, (u16) task_size);

	/* Current header size plus static size and dynamic size. */
	header_size += 2 * sizeof(u64);

	/* Do we fit in with the current stack dump size? */
	if ((u16) (header_size + stack_size) < header_size) {
		/*
		 * If we overflow the maximum size for the sample,
		 * we customize the stack dump size to fit in.
		 */
		stack_size = USHRT_MAX - header_size - sizeof(u64);
		stack_size = round_up(stack_size, sizeof(u64));
	}

	return stack_size;
}

static void
perf_output_sample_ustack(struct perf_output_handle *handle, u64 dump_size,
			  struct pt_regs *regs)
{
	/* Case of a kernel thread, nothing to dump */
	if (!regs) {
		u64 size = 0;
		perf_output_put(handle, size);
	} else {
		unsigned long sp;
		unsigned int rem;
		u64 dyn_size;

		/*
		 * We dump:
		 * static size
		 *   - the size requested by user or the best one we can fit
		 *     in to the sample max size
		 * data
		 *   - user stack dump data
		 * dynamic size
		 *   - the actual dumped size
		 */

		/* Static size. */
		perf_output_put(handle, dump_size);

		/* Data. */
		sp = perf_user_stack_pointer(regs);
		rem = __output_copy_user(handle, (void *) sp, dump_size);
		dyn_size = dump_size - rem;

		perf_output_skip(handle, rem);

		/* Dynamic size. */
		perf_output_put(handle, dyn_size);
	}
}

5469 5470 5471
static void __perf_event_header__init_id(struct perf_event_header *header,
					 struct perf_sample_data *data,
					 struct perf_event *event)
5472 5473 5474 5475 5476 5477 5478 5479 5480 5481 5482 5483 5484
{
	u64 sample_type = event->attr.sample_type;

	data->type = sample_type;
	header->size += event->id_header_size;

	if (sample_type & PERF_SAMPLE_TID) {
		/* namespace issues */
		data->tid_entry.pid = perf_event_pid(event, current);
		data->tid_entry.tid = perf_event_tid(event, current);
	}

	if (sample_type & PERF_SAMPLE_TIME)
5485
		data->time = perf_event_clock(event);
5486

5487
	if (sample_type & (PERF_SAMPLE_ID | PERF_SAMPLE_IDENTIFIER))
5488 5489 5490 5491 5492 5493 5494 5495 5496 5497 5498
		data->id = primary_event_id(event);

	if (sample_type & PERF_SAMPLE_STREAM_ID)
		data->stream_id = event->id;

	if (sample_type & PERF_SAMPLE_CPU) {
		data->cpu_entry.cpu	 = raw_smp_processor_id();
		data->cpu_entry.reserved = 0;
	}
}

5499 5500 5501
void perf_event_header__init_id(struct perf_event_header *header,
				struct perf_sample_data *data,
				struct perf_event *event)
5502 5503 5504 5505 5506 5507 5508 5509 5510 5511 5512 5513 5514 5515 5516 5517 5518 5519 5520 5521 5522 5523 5524 5525
{
	if (event->attr.sample_id_all)
		__perf_event_header__init_id(header, data, event);
}

static void __perf_event__output_id_sample(struct perf_output_handle *handle,
					   struct perf_sample_data *data)
{
	u64 sample_type = data->type;

	if (sample_type & PERF_SAMPLE_TID)
		perf_output_put(handle, data->tid_entry);

	if (sample_type & PERF_SAMPLE_TIME)
		perf_output_put(handle, data->time);

	if (sample_type & PERF_SAMPLE_ID)
		perf_output_put(handle, data->id);

	if (sample_type & PERF_SAMPLE_STREAM_ID)
		perf_output_put(handle, data->stream_id);

	if (sample_type & PERF_SAMPLE_CPU)
		perf_output_put(handle, data->cpu_entry);
5526 5527 5528

	if (sample_type & PERF_SAMPLE_IDENTIFIER)
		perf_output_put(handle, data->id);
5529 5530
}

5531 5532 5533
void perf_event__output_id_sample(struct perf_event *event,
				  struct perf_output_handle *handle,
				  struct perf_sample_data *sample)
5534 5535 5536 5537 5538
{
	if (event->attr.sample_id_all)
		__perf_event__output_id_sample(handle, sample);
}

5539
static void perf_output_read_one(struct perf_output_handle *handle,
5540 5541
				 struct perf_event *event,
				 u64 enabled, u64 running)
5542
{
5543
	u64 read_format = event->attr.read_format;
5544 5545 5546
	u64 values[4];
	int n = 0;

P
Peter Zijlstra 已提交
5547
	values[n++] = perf_event_count(event);
5548
	if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED) {
5549
		values[n++] = enabled +
5550
			atomic64_read(&event->child_total_time_enabled);
5551 5552
	}
	if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING) {
5553
		values[n++] = running +
5554
			atomic64_read(&event->child_total_time_running);
5555 5556
	}
	if (read_format & PERF_FORMAT_ID)
5557
		values[n++] = primary_event_id(event);
5558

5559
	__output_copy(handle, values, n * sizeof(u64));
5560 5561 5562
}

/*
5563
 * XXX PERF_FORMAT_GROUP vs inherited events seems difficult.
5564 5565
 */
static void perf_output_read_group(struct perf_output_handle *handle,
5566 5567
			    struct perf_event *event,
			    u64 enabled, u64 running)
5568
{
5569 5570
	struct perf_event *leader = event->group_leader, *sub;
	u64 read_format = event->attr.read_format;
5571 5572 5573 5574 5575 5576
	u64 values[5];
	int n = 0;

	values[n++] = 1 + leader->nr_siblings;

	if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED)
5577
		values[n++] = enabled;
5578 5579

	if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING)
5580
		values[n++] = running;
5581

5582
	if (leader != event)
5583 5584
		leader->pmu->read(leader);

P
Peter Zijlstra 已提交
5585
	values[n++] = perf_event_count(leader);
5586
	if (read_format & PERF_FORMAT_ID)
5587
		values[n++] = primary_event_id(leader);
5588

5589
	__output_copy(handle, values, n * sizeof(u64));
5590

5591
	list_for_each_entry(sub, &leader->sibling_list, group_entry) {
5592 5593
		n = 0;

5594 5595
		if ((sub != event) &&
		    (sub->state == PERF_EVENT_STATE_ACTIVE))
5596 5597
			sub->pmu->read(sub);

P
Peter Zijlstra 已提交
5598
		values[n++] = perf_event_count(sub);
5599
		if (read_format & PERF_FORMAT_ID)
5600
			values[n++] = primary_event_id(sub);
5601

5602
		__output_copy(handle, values, n * sizeof(u64));
5603 5604 5605
	}
}

5606 5607 5608
#define PERF_FORMAT_TOTAL_TIMES (PERF_FORMAT_TOTAL_TIME_ENABLED|\
				 PERF_FORMAT_TOTAL_TIME_RUNNING)

5609
static void perf_output_read(struct perf_output_handle *handle,
5610
			     struct perf_event *event)
5611
{
5612
	u64 enabled = 0, running = 0, now;
5613 5614 5615 5616 5617 5618 5619 5620 5621 5622 5623
	u64 read_format = event->attr.read_format;

	/*
	 * compute total_time_enabled, total_time_running
	 * based on snapshot values taken when the event
	 * was last scheduled in.
	 *
	 * we cannot simply called update_context_time()
	 * because of locking issue as we are called in
	 * NMI context
	 */
5624
	if (read_format & PERF_FORMAT_TOTAL_TIMES)
5625
		calc_timer_values(event, &now, &enabled, &running);
5626

5627
	if (event->attr.read_format & PERF_FORMAT_GROUP)
5628
		perf_output_read_group(handle, event, enabled, running);
5629
	else
5630
		perf_output_read_one(handle, event, enabled, running);
5631 5632
}

5633 5634 5635
void perf_output_sample(struct perf_output_handle *handle,
			struct perf_event_header *header,
			struct perf_sample_data *data,
5636
			struct perf_event *event)
5637 5638 5639 5640 5641
{
	u64 sample_type = data->type;

	perf_output_put(handle, *header);

5642 5643 5644
	if (sample_type & PERF_SAMPLE_IDENTIFIER)
		perf_output_put(handle, data->id);

5645 5646 5647 5648 5649 5650 5651 5652 5653 5654 5655 5656 5657 5658 5659 5660 5661 5662 5663 5664 5665 5666 5667 5668 5669
	if (sample_type & PERF_SAMPLE_IP)
		perf_output_put(handle, data->ip);

	if (sample_type & PERF_SAMPLE_TID)
		perf_output_put(handle, data->tid_entry);

	if (sample_type & PERF_SAMPLE_TIME)
		perf_output_put(handle, data->time);

	if (sample_type & PERF_SAMPLE_ADDR)
		perf_output_put(handle, data->addr);

	if (sample_type & PERF_SAMPLE_ID)
		perf_output_put(handle, data->id);

	if (sample_type & PERF_SAMPLE_STREAM_ID)
		perf_output_put(handle, data->stream_id);

	if (sample_type & PERF_SAMPLE_CPU)
		perf_output_put(handle, data->cpu_entry);

	if (sample_type & PERF_SAMPLE_PERIOD)
		perf_output_put(handle, data->period);

	if (sample_type & PERF_SAMPLE_READ)
5670
		perf_output_read(handle, event);
5671 5672 5673 5674 5675 5676 5677 5678 5679 5680

	if (sample_type & PERF_SAMPLE_CALLCHAIN) {
		if (data->callchain) {
			int size = 1;

			if (data->callchain)
				size += data->callchain->nr;

			size *= sizeof(u64);

5681
			__output_copy(handle, data->callchain, size);
5682 5683 5684 5685 5686 5687 5688
		} else {
			u64 nr = 0;
			perf_output_put(handle, nr);
		}
	}

	if (sample_type & PERF_SAMPLE_RAW) {
5689 5690 5691 5692 5693 5694 5695 5696 5697 5698 5699 5700 5701 5702 5703 5704 5705 5706 5707 5708
		struct perf_raw_record *raw = data->raw;

		if (raw) {
			struct perf_raw_frag *frag = &raw->frag;

			perf_output_put(handle, raw->size);
			do {
				if (frag->copy) {
					__output_custom(handle, frag->copy,
							frag->data, frag->size);
				} else {
					__output_copy(handle, frag->data,
						      frag->size);
				}
				if (perf_raw_frag_last(frag))
					break;
				frag = frag->next;
			} while (1);
			if (frag->pad)
				__output_skip(handle, NULL, frag->pad);
5709 5710 5711 5712 5713 5714 5715 5716 5717 5718 5719
		} else {
			struct {
				u32	size;
				u32	data;
			} raw = {
				.size = sizeof(u32),
				.data = 0,
			};
			perf_output_put(handle, raw);
		}
	}
5720

5721 5722 5723 5724 5725 5726 5727 5728 5729 5730 5731 5732 5733 5734 5735 5736 5737
	if (sample_type & PERF_SAMPLE_BRANCH_STACK) {
		if (data->br_stack) {
			size_t size;

			size = data->br_stack->nr
			     * sizeof(struct perf_branch_entry);

			perf_output_put(handle, data->br_stack->nr);
			perf_output_copy(handle, data->br_stack->entries, size);
		} else {
			/*
			 * we always store at least the value of nr
			 */
			u64 nr = 0;
			perf_output_put(handle, nr);
		}
	}
5738 5739 5740 5741 5742 5743 5744 5745 5746 5747 5748 5749 5750 5751 5752 5753 5754

	if (sample_type & PERF_SAMPLE_REGS_USER) {
		u64 abi = data->regs_user.abi;

		/*
		 * If there are no regs to dump, notice it through
		 * first u64 being zero (PERF_SAMPLE_REGS_ABI_NONE).
		 */
		perf_output_put(handle, abi);

		if (abi) {
			u64 mask = event->attr.sample_regs_user;
			perf_output_sample_regs(handle,
						data->regs_user.regs,
						mask);
		}
	}
5755

5756
	if (sample_type & PERF_SAMPLE_STACK_USER) {
5757 5758 5759
		perf_output_sample_ustack(handle,
					  data->stack_user_size,
					  data->regs_user.regs);
5760
	}
A
Andi Kleen 已提交
5761 5762 5763

	if (sample_type & PERF_SAMPLE_WEIGHT)
		perf_output_put(handle, data->weight);
5764 5765 5766

	if (sample_type & PERF_SAMPLE_DATA_SRC)
		perf_output_put(handle, data->data_src.val);
5767

A
Andi Kleen 已提交
5768 5769 5770
	if (sample_type & PERF_SAMPLE_TRANSACTION)
		perf_output_put(handle, data->txn);

5771 5772 5773 5774 5775 5776 5777 5778 5779 5780 5781 5782 5783 5784 5785 5786 5787
	if (sample_type & PERF_SAMPLE_REGS_INTR) {
		u64 abi = data->regs_intr.abi;
		/*
		 * If there are no regs to dump, notice it through
		 * first u64 being zero (PERF_SAMPLE_REGS_ABI_NONE).
		 */
		perf_output_put(handle, abi);

		if (abi) {
			u64 mask = event->attr.sample_regs_intr;

			perf_output_sample_regs(handle,
						data->regs_intr.regs,
						mask);
		}
	}

5788 5789 5790 5791 5792 5793 5794 5795 5796 5797 5798 5799 5800
	if (!event->attr.watermark) {
		int wakeup_events = event->attr.wakeup_events;

		if (wakeup_events) {
			struct ring_buffer *rb = handle->rb;
			int events = local_inc_return(&rb->events);

			if (events >= wakeup_events) {
				local_sub(wakeup_events, &rb->events);
				local_inc(&rb->wakeup);
			}
		}
	}
5801 5802 5803 5804
}

void perf_prepare_sample(struct perf_event_header *header,
			 struct perf_sample_data *data,
5805
			 struct perf_event *event,
5806
			 struct pt_regs *regs)
5807
{
5808
	u64 sample_type = event->attr.sample_type;
5809

5810
	header->type = PERF_RECORD_SAMPLE;
5811
	header->size = sizeof(*header) + event->header_size;
5812 5813 5814

	header->misc = 0;
	header->misc |= perf_misc_flags(regs);
5815

5816
	__perf_event_header__init_id(header, data, event);
5817

5818
	if (sample_type & PERF_SAMPLE_IP)
5819 5820
		data->ip = perf_instruction_pointer(regs);

5821
	if (sample_type & PERF_SAMPLE_CALLCHAIN) {
5822
		int size = 1;
5823

5824
		data->callchain = perf_callchain(event, regs);
5825 5826 5827 5828 5829

		if (data->callchain)
			size += data->callchain->nr;

		header->size += size * sizeof(u64);
5830 5831
	}

5832
	if (sample_type & PERF_SAMPLE_RAW) {
5833 5834 5835 5836 5837 5838 5839 5840 5841 5842 5843 5844 5845 5846 5847 5848 5849 5850 5851 5852
		struct perf_raw_record *raw = data->raw;
		int size;

		if (raw) {
			struct perf_raw_frag *frag = &raw->frag;
			u32 sum = 0;

			do {
				sum += frag->size;
				if (perf_raw_frag_last(frag))
					break;
				frag = frag->next;
			} while (1);

			size = round_up(sum + sizeof(u32), sizeof(u64));
			raw->size = size - sizeof(u32);
			frag->pad = raw->size - sum;
		} else {
			size = sizeof(u64);
		}
5853

5854
		header->size += size;
5855
	}
5856 5857 5858 5859 5860 5861 5862 5863 5864

	if (sample_type & PERF_SAMPLE_BRANCH_STACK) {
		int size = sizeof(u64); /* nr */
		if (data->br_stack) {
			size += data->br_stack->nr
			      * sizeof(struct perf_branch_entry);
		}
		header->size += size;
	}
5865

5866
	if (sample_type & (PERF_SAMPLE_REGS_USER | PERF_SAMPLE_STACK_USER))
5867 5868
		perf_sample_regs_user(&data->regs_user, regs,
				      &data->regs_user_copy);
5869

5870 5871 5872 5873 5874 5875 5876 5877 5878 5879 5880
	if (sample_type & PERF_SAMPLE_REGS_USER) {
		/* regs dump ABI info */
		int size = sizeof(u64);

		if (data->regs_user.regs) {
			u64 mask = event->attr.sample_regs_user;
			size += hweight64(mask) * sizeof(u64);
		}

		header->size += size;
	}
5881 5882 5883 5884 5885 5886 5887 5888 5889 5890 5891 5892

	if (sample_type & PERF_SAMPLE_STACK_USER) {
		/*
		 * Either we need PERF_SAMPLE_STACK_USER bit to be allways
		 * processed as the last one or have additional check added
		 * in case new sample type is added, because we could eat
		 * up the rest of the sample size.
		 */
		u16 stack_size = event->attr.sample_stack_user;
		u16 size = sizeof(u64);

		stack_size = perf_sample_ustack_size(stack_size, header->size,
5893
						     data->regs_user.regs);
5894 5895 5896 5897 5898 5899 5900 5901 5902 5903 5904 5905

		/*
		 * If there is something to dump, add space for the dump
		 * itself and for the field that tells the dynamic size,
		 * which is how many have been actually dumped.
		 */
		if (stack_size)
			size += sizeof(u64) + stack_size;

		data->stack_user_size = stack_size;
		header->size += size;
	}
5906 5907 5908 5909 5910 5911 5912 5913 5914 5915 5916 5917 5918 5919 5920

	if (sample_type & PERF_SAMPLE_REGS_INTR) {
		/* regs dump ABI info */
		int size = sizeof(u64);

		perf_sample_regs_intr(&data->regs_intr, regs);

		if (data->regs_intr.regs) {
			u64 mask = event->attr.sample_regs_intr;

			size += hweight64(mask) * sizeof(u64);
		}

		header->size += size;
	}
5921
}
5922

5923 5924 5925 5926 5927 5928 5929
static void __always_inline
__perf_event_output(struct perf_event *event,
		    struct perf_sample_data *data,
		    struct pt_regs *regs,
		    int (*output_begin)(struct perf_output_handle *,
					struct perf_event *,
					unsigned int))
5930 5931 5932
{
	struct perf_output_handle handle;
	struct perf_event_header header;
5933

5934 5935 5936
	/* protect the callchain buffers */
	rcu_read_lock();

5937
	perf_prepare_sample(&header, data, event, regs);
P
Peter Zijlstra 已提交
5938

5939
	if (output_begin(&handle, event, header.size))
5940
		goto exit;
5941

5942
	perf_output_sample(&handle, &header, data, event);
5943

5944
	perf_output_end(&handle);
5945 5946 5947

exit:
	rcu_read_unlock();
5948 5949
}

5950 5951 5952 5953 5954 5955 5956 5957 5958 5959 5960 5961 5962 5963 5964 5965 5966 5967 5968 5969 5970 5971 5972 5973
void
perf_event_output_forward(struct perf_event *event,
			 struct perf_sample_data *data,
			 struct pt_regs *regs)
{
	__perf_event_output(event, data, regs, perf_output_begin_forward);
}

void
perf_event_output_backward(struct perf_event *event,
			   struct perf_sample_data *data,
			   struct pt_regs *regs)
{
	__perf_event_output(event, data, regs, perf_output_begin_backward);
}

void
perf_event_output(struct perf_event *event,
		  struct perf_sample_data *data,
		  struct pt_regs *regs)
{
	__perf_event_output(event, data, regs, perf_output_begin);
}

5974
/*
5975
 * read event_id
5976 5977 5978 5979 5980 5981 5982 5983 5984 5985
 */

struct perf_read_event {
	struct perf_event_header	header;

	u32				pid;
	u32				tid;
};

static void
5986
perf_event_read_event(struct perf_event *event,
5987 5988 5989
			struct task_struct *task)
{
	struct perf_output_handle handle;
5990
	struct perf_sample_data sample;
5991
	struct perf_read_event read_event = {
5992
		.header = {
5993
			.type = PERF_RECORD_READ,
5994
			.misc = 0,
5995
			.size = sizeof(read_event) + event->read_size,
5996
		},
5997 5998
		.pid = perf_event_pid(event, task),
		.tid = perf_event_tid(event, task),
5999
	};
6000
	int ret;
6001

6002
	perf_event_header__init_id(&read_event.header, &sample, event);
6003
	ret = perf_output_begin(&handle, event, read_event.header.size);
6004 6005 6006
	if (ret)
		return;

6007
	perf_output_put(&handle, read_event);
6008
	perf_output_read(&handle, event);
6009
	perf_event__output_id_sample(event, &handle, &sample);
6010

6011 6012 6013
	perf_output_end(&handle);
}

6014
typedef void (perf_iterate_f)(struct perf_event *event, void *data);
6015 6016

static void
6017 6018
perf_iterate_ctx(struct perf_event_context *ctx,
		   perf_iterate_f output,
6019
		   void *data, bool all)
6020 6021 6022 6023
{
	struct perf_event *event;

	list_for_each_entry_rcu(event, &ctx->event_list, event_entry) {
6024 6025 6026 6027 6028 6029 6030
		if (!all) {
			if (event->state < PERF_EVENT_STATE_INACTIVE)
				continue;
			if (!event_filter_match(event))
				continue;
		}

6031
		output(event, data);
6032 6033 6034
	}
}

6035
static void perf_iterate_sb_cpu(perf_iterate_f output, void *data)
6036 6037 6038 6039 6040
{
	struct pmu_event_list *pel = this_cpu_ptr(&pmu_sb_events);
	struct perf_event *event;

	list_for_each_entry_rcu(event, &pel->list, sb_list) {
6041 6042 6043 6044 6045 6046 6047 6048
		/*
		 * Skip events that are not fully formed yet; ensure that
		 * if we observe event->ctx, both event and ctx will be
		 * complete enough. See perf_install_in_context().
		 */
		if (!smp_load_acquire(&event->ctx))
			continue;

6049 6050 6051 6052 6053 6054 6055 6056
		if (event->state < PERF_EVENT_STATE_INACTIVE)
			continue;
		if (!event_filter_match(event))
			continue;
		output(event, data);
	}
}

6057 6058 6059 6060 6061 6062
/*
 * Iterate all events that need to receive side-band events.
 *
 * For new callers; ensure that account_pmu_sb_event() includes
 * your event, otherwise it might not get delivered.
 */
6063
static void
6064
perf_iterate_sb(perf_iterate_f output, void *data,
6065 6066 6067 6068 6069
	       struct perf_event_context *task_ctx)
{
	struct perf_event_context *ctx;
	int ctxn;

6070 6071 6072
	rcu_read_lock();
	preempt_disable();

J
Jiri Olsa 已提交
6073
	/*
6074 6075
	 * If we have task_ctx != NULL we only notify the task context itself.
	 * The task_ctx is set only for EXIT events before releasing task
J
Jiri Olsa 已提交
6076 6077 6078
	 * context.
	 */
	if (task_ctx) {
6079 6080
		perf_iterate_ctx(task_ctx, output, data, false);
		goto done;
J
Jiri Olsa 已提交
6081 6082
	}

6083
	perf_iterate_sb_cpu(output, data);
6084 6085

	for_each_task_context_nr(ctxn) {
6086 6087
		ctx = rcu_dereference(current->perf_event_ctxp[ctxn]);
		if (ctx)
6088
			perf_iterate_ctx(ctx, output, data, false);
6089
	}
6090
done:
6091
	preempt_enable();
6092
	rcu_read_unlock();
6093 6094
}

6095 6096 6097 6098 6099 6100 6101 6102 6103 6104 6105 6106 6107 6108 6109 6110 6111 6112 6113 6114 6115 6116 6117 6118 6119 6120 6121 6122 6123 6124 6125 6126 6127 6128 6129 6130 6131 6132 6133 6134 6135 6136 6137 6138 6139
/*
 * Clear all file-based filters at exec, they'll have to be
 * re-instated when/if these objects are mmapped again.
 */
static void perf_event_addr_filters_exec(struct perf_event *event, void *data)
{
	struct perf_addr_filters_head *ifh = perf_event_addr_filters(event);
	struct perf_addr_filter *filter;
	unsigned int restart = 0, count = 0;
	unsigned long flags;

	if (!has_addr_filter(event))
		return;

	raw_spin_lock_irqsave(&ifh->lock, flags);
	list_for_each_entry(filter, &ifh->list, entry) {
		if (filter->inode) {
			event->addr_filters_offs[count] = 0;
			restart++;
		}

		count++;
	}

	if (restart)
		event->addr_filters_gen++;
	raw_spin_unlock_irqrestore(&ifh->lock, flags);

	if (restart)
		perf_event_restart(event);
}

void perf_event_exec(void)
{
	struct perf_event_context *ctx;
	int ctxn;

	rcu_read_lock();
	for_each_task_context_nr(ctxn) {
		ctx = current->perf_event_ctxp[ctxn];
		if (!ctx)
			continue;

		perf_event_enable_on_exec(ctxn);

6140
		perf_iterate_ctx(ctx, perf_event_addr_filters_exec, NULL,
6141 6142 6143 6144 6145
				   true);
	}
	rcu_read_unlock();
}

6146 6147 6148 6149 6150 6151 6152 6153 6154 6155
struct remote_output {
	struct ring_buffer	*rb;
	int			err;
};

static void __perf_event_output_stop(struct perf_event *event, void *data)
{
	struct perf_event *parent = event->parent;
	struct remote_output *ro = data;
	struct ring_buffer *rb = ro->rb;
6156 6157 6158
	struct stop_event_data sd = {
		.event	= event,
	};
6159 6160 6161 6162 6163 6164 6165 6166 6167 6168 6169 6170

	if (!has_aux(event))
		return;

	if (!parent)
		parent = event;

	/*
	 * In case of inheritance, it will be the parent that links to the
	 * ring-buffer, but it will be the child that's actually using it:
	 */
	if (rcu_dereference(parent->rb) == rb)
6171
		ro->err = __perf_event_stop(&sd);
6172 6173 6174 6175 6176 6177 6178 6179 6180 6181 6182 6183
}

static int __perf_pmu_output_stop(void *info)
{
	struct perf_event *event = info;
	struct pmu *pmu = event->pmu;
	struct perf_cpu_context *cpuctx = get_cpu_ptr(pmu->pmu_cpu_context);
	struct remote_output ro = {
		.rb	= event->rb,
	};

	rcu_read_lock();
6184
	perf_iterate_ctx(&cpuctx->ctx, __perf_event_output_stop, &ro, false);
6185
	if (cpuctx->task_ctx)
6186
		perf_iterate_ctx(cpuctx->task_ctx, __perf_event_output_stop,
6187
				   &ro, false);
6188 6189 6190 6191 6192 6193 6194 6195 6196 6197 6198 6199 6200 6201 6202 6203 6204 6205 6206 6207 6208 6209 6210 6211 6212 6213 6214 6215 6216 6217 6218 6219 6220
	rcu_read_unlock();

	return ro.err;
}

static void perf_pmu_output_stop(struct perf_event *event)
{
	struct perf_event *iter;
	int err, cpu;

restart:
	rcu_read_lock();
	list_for_each_entry_rcu(iter, &event->rb->event_list, rb_entry) {
		/*
		 * For per-CPU events, we need to make sure that neither they
		 * nor their children are running; for cpu==-1 events it's
		 * sufficient to stop the event itself if it's active, since
		 * it can't have children.
		 */
		cpu = iter->cpu;
		if (cpu == -1)
			cpu = READ_ONCE(iter->oncpu);

		if (cpu == -1)
			continue;

		err = cpu_function_call(cpu, __perf_pmu_output_stop, event);
		if (err == -EAGAIN) {
			rcu_read_unlock();
			goto restart;
		}
	}
	rcu_read_unlock();
6221 6222
}

P
Peter Zijlstra 已提交
6223
/*
P
Peter Zijlstra 已提交
6224 6225
 * task tracking -- fork/exit
 *
6226
 * enabled by: attr.comm | attr.mmap | attr.mmap2 | attr.mmap_data | attr.task
P
Peter Zijlstra 已提交
6227 6228
 */

P
Peter Zijlstra 已提交
6229
struct perf_task_event {
6230
	struct task_struct		*task;
6231
	struct perf_event_context	*task_ctx;
P
Peter Zijlstra 已提交
6232 6233 6234 6235 6236 6237

	struct {
		struct perf_event_header	header;

		u32				pid;
		u32				ppid;
P
Peter Zijlstra 已提交
6238 6239
		u32				tid;
		u32				ptid;
6240
		u64				time;
6241
	} event_id;
P
Peter Zijlstra 已提交
6242 6243
};

6244 6245
static int perf_event_task_match(struct perf_event *event)
{
6246 6247 6248
	return event->attr.comm  || event->attr.mmap ||
	       event->attr.mmap2 || event->attr.mmap_data ||
	       event->attr.task;
6249 6250
}

6251
static void perf_event_task_output(struct perf_event *event,
6252
				   void *data)
P
Peter Zijlstra 已提交
6253
{
6254
	struct perf_task_event *task_event = data;
P
Peter Zijlstra 已提交
6255
	struct perf_output_handle handle;
6256
	struct perf_sample_data	sample;
P
Peter Zijlstra 已提交
6257
	struct task_struct *task = task_event->task;
6258
	int ret, size = task_event->event_id.header.size;
6259

6260 6261 6262
	if (!perf_event_task_match(event))
		return;

6263
	perf_event_header__init_id(&task_event->event_id.header, &sample, event);
P
Peter Zijlstra 已提交
6264

6265
	ret = perf_output_begin(&handle, event,
6266
				task_event->event_id.header.size);
6267
	if (ret)
6268
		goto out;
P
Peter Zijlstra 已提交
6269

6270 6271
	task_event->event_id.pid = perf_event_pid(event, task);
	task_event->event_id.ppid = perf_event_pid(event, current);
P
Peter Zijlstra 已提交
6272

6273 6274
	task_event->event_id.tid = perf_event_tid(event, task);
	task_event->event_id.ptid = perf_event_tid(event, current);
P
Peter Zijlstra 已提交
6275

6276 6277
	task_event->event_id.time = perf_event_clock(event);

6278
	perf_output_put(&handle, task_event->event_id);
6279

6280 6281
	perf_event__output_id_sample(event, &handle, &sample);

P
Peter Zijlstra 已提交
6282
	perf_output_end(&handle);
6283 6284
out:
	task_event->event_id.header.size = size;
P
Peter Zijlstra 已提交
6285 6286
}

6287 6288
static void perf_event_task(struct task_struct *task,
			      struct perf_event_context *task_ctx,
6289
			      int new)
P
Peter Zijlstra 已提交
6290
{
P
Peter Zijlstra 已提交
6291
	struct perf_task_event task_event;
P
Peter Zijlstra 已提交
6292

6293 6294 6295
	if (!atomic_read(&nr_comm_events) &&
	    !atomic_read(&nr_mmap_events) &&
	    !atomic_read(&nr_task_events))
P
Peter Zijlstra 已提交
6296 6297
		return;

P
Peter Zijlstra 已提交
6298
	task_event = (struct perf_task_event){
6299 6300
		.task	  = task,
		.task_ctx = task_ctx,
6301
		.event_id    = {
P
Peter Zijlstra 已提交
6302
			.header = {
6303
				.type = new ? PERF_RECORD_FORK : PERF_RECORD_EXIT,
6304
				.misc = 0,
6305
				.size = sizeof(task_event.event_id),
P
Peter Zijlstra 已提交
6306
			},
6307 6308
			/* .pid  */
			/* .ppid */
P
Peter Zijlstra 已提交
6309 6310
			/* .tid  */
			/* .ptid */
6311
			/* .time */
P
Peter Zijlstra 已提交
6312 6313 6314
		},
	};

6315
	perf_iterate_sb(perf_event_task_output,
6316 6317
		       &task_event,
		       task_ctx);
P
Peter Zijlstra 已提交
6318 6319
}

6320
void perf_event_fork(struct task_struct *task)
P
Peter Zijlstra 已提交
6321
{
6322
	perf_event_task(task, NULL, 1);
P
Peter Zijlstra 已提交
6323 6324
}

6325 6326 6327 6328 6329
/*
 * comm tracking
 */

struct perf_comm_event {
6330 6331
	struct task_struct	*task;
	char			*comm;
6332 6333 6334 6335 6336 6337 6338
	int			comm_size;

	struct {
		struct perf_event_header	header;

		u32				pid;
		u32				tid;
6339
	} event_id;
6340 6341
};

6342 6343 6344 6345 6346
static int perf_event_comm_match(struct perf_event *event)
{
	return event->attr.comm;
}

6347
static void perf_event_comm_output(struct perf_event *event,
6348
				   void *data)
6349
{
6350
	struct perf_comm_event *comm_event = data;
6351
	struct perf_output_handle handle;
6352
	struct perf_sample_data sample;
6353
	int size = comm_event->event_id.header.size;
6354 6355
	int ret;

6356 6357 6358
	if (!perf_event_comm_match(event))
		return;

6359 6360
	perf_event_header__init_id(&comm_event->event_id.header, &sample, event);
	ret = perf_output_begin(&handle, event,
6361
				comm_event->event_id.header.size);
6362 6363

	if (ret)
6364
		goto out;
6365

6366 6367
	comm_event->event_id.pid = perf_event_pid(event, comm_event->task);
	comm_event->event_id.tid = perf_event_tid(event, comm_event->task);
6368

6369
	perf_output_put(&handle, comm_event->event_id);
6370
	__output_copy(&handle, comm_event->comm,
6371
				   comm_event->comm_size);
6372 6373 6374

	perf_event__output_id_sample(event, &handle, &sample);

6375
	perf_output_end(&handle);
6376 6377
out:
	comm_event->event_id.header.size = size;
6378 6379
}

6380
static void perf_event_comm_event(struct perf_comm_event *comm_event)
6381
{
6382
	char comm[TASK_COMM_LEN];
6383 6384
	unsigned int size;

6385
	memset(comm, 0, sizeof(comm));
6386
	strlcpy(comm, comm_event->task->comm, sizeof(comm));
6387
	size = ALIGN(strlen(comm)+1, sizeof(u64));
6388 6389 6390 6391

	comm_event->comm = comm;
	comm_event->comm_size = size;

6392
	comm_event->event_id.header.size = sizeof(comm_event->event_id) + size;
P
Peter Zijlstra 已提交
6393

6394
	perf_iterate_sb(perf_event_comm_output,
6395 6396
		       comm_event,
		       NULL);
6397 6398
}

6399
void perf_event_comm(struct task_struct *task, bool exec)
6400
{
6401 6402
	struct perf_comm_event comm_event;

6403
	if (!atomic_read(&nr_comm_events))
6404
		return;
6405

6406
	comm_event = (struct perf_comm_event){
6407
		.task	= task,
6408 6409
		/* .comm      */
		/* .comm_size */
6410
		.event_id  = {
6411
			.header = {
6412
				.type = PERF_RECORD_COMM,
6413
				.misc = exec ? PERF_RECORD_MISC_COMM_EXEC : 0,
6414 6415 6416 6417
				/* .size */
			},
			/* .pid */
			/* .tid */
6418 6419 6420
		},
	};

6421
	perf_event_comm_event(&comm_event);
6422 6423
}

6424 6425 6426 6427 6428
/*
 * mmap tracking
 */

struct perf_mmap_event {
6429 6430 6431 6432
	struct vm_area_struct	*vma;

	const char		*file_name;
	int			file_size;
6433 6434 6435
	int			maj, min;
	u64			ino;
	u64			ino_generation;
6436
	u32			prot, flags;
6437 6438 6439 6440 6441 6442 6443 6444 6445

	struct {
		struct perf_event_header	header;

		u32				pid;
		u32				tid;
		u64				start;
		u64				len;
		u64				pgoff;
6446
	} event_id;
6447 6448
};

6449 6450 6451 6452 6453 6454 6455 6456
static int perf_event_mmap_match(struct perf_event *event,
				 void *data)
{
	struct perf_mmap_event *mmap_event = data;
	struct vm_area_struct *vma = mmap_event->vma;
	int executable = vma->vm_flags & VM_EXEC;

	return (!executable && event->attr.mmap_data) ||
6457
	       (executable && (event->attr.mmap || event->attr.mmap2));
6458 6459
}

6460
static void perf_event_mmap_output(struct perf_event *event,
6461
				   void *data)
6462
{
6463
	struct perf_mmap_event *mmap_event = data;
6464
	struct perf_output_handle handle;
6465
	struct perf_sample_data sample;
6466
	int size = mmap_event->event_id.header.size;
6467
	int ret;
6468

6469 6470 6471
	if (!perf_event_mmap_match(event, data))
		return;

6472 6473 6474 6475 6476
	if (event->attr.mmap2) {
		mmap_event->event_id.header.type = PERF_RECORD_MMAP2;
		mmap_event->event_id.header.size += sizeof(mmap_event->maj);
		mmap_event->event_id.header.size += sizeof(mmap_event->min);
		mmap_event->event_id.header.size += sizeof(mmap_event->ino);
6477
		mmap_event->event_id.header.size += sizeof(mmap_event->ino_generation);
6478 6479
		mmap_event->event_id.header.size += sizeof(mmap_event->prot);
		mmap_event->event_id.header.size += sizeof(mmap_event->flags);
6480 6481
	}

6482 6483
	perf_event_header__init_id(&mmap_event->event_id.header, &sample, event);
	ret = perf_output_begin(&handle, event,
6484
				mmap_event->event_id.header.size);
6485
	if (ret)
6486
		goto out;
6487

6488 6489
	mmap_event->event_id.pid = perf_event_pid(event, current);
	mmap_event->event_id.tid = perf_event_tid(event, current);
6490

6491
	perf_output_put(&handle, mmap_event->event_id);
6492 6493 6494 6495 6496 6497

	if (event->attr.mmap2) {
		perf_output_put(&handle, mmap_event->maj);
		perf_output_put(&handle, mmap_event->min);
		perf_output_put(&handle, mmap_event->ino);
		perf_output_put(&handle, mmap_event->ino_generation);
6498 6499
		perf_output_put(&handle, mmap_event->prot);
		perf_output_put(&handle, mmap_event->flags);
6500 6501
	}

6502
	__output_copy(&handle, mmap_event->file_name,
6503
				   mmap_event->file_size);
6504 6505 6506

	perf_event__output_id_sample(event, &handle, &sample);

6507
	perf_output_end(&handle);
6508 6509
out:
	mmap_event->event_id.header.size = size;
6510 6511
}

6512
static void perf_event_mmap_event(struct perf_mmap_event *mmap_event)
6513
{
6514 6515
	struct vm_area_struct *vma = mmap_event->vma;
	struct file *file = vma->vm_file;
6516 6517
	int maj = 0, min = 0;
	u64 ino = 0, gen = 0;
6518
	u32 prot = 0, flags = 0;
6519 6520 6521
	unsigned int size;
	char tmp[16];
	char *buf = NULL;
6522
	char *name;
6523

6524
	if (file) {
6525 6526
		struct inode *inode;
		dev_t dev;
6527

6528
		buf = kmalloc(PATH_MAX, GFP_KERNEL);
6529
		if (!buf) {
6530 6531
			name = "//enomem";
			goto cpy_name;
6532
		}
6533
		/*
6534
		 * d_path() works from the end of the rb backwards, so we
6535 6536 6537
		 * need to add enough zero bytes after the string to handle
		 * the 64bit alignment we do later.
		 */
M
Miklos Szeredi 已提交
6538
		name = file_path(file, buf, PATH_MAX - sizeof(u64));
6539
		if (IS_ERR(name)) {
6540 6541
			name = "//toolong";
			goto cpy_name;
6542
		}
6543 6544 6545 6546 6547 6548
		inode = file_inode(vma->vm_file);
		dev = inode->i_sb->s_dev;
		ino = inode->i_ino;
		gen = inode->i_generation;
		maj = MAJOR(dev);
		min = MINOR(dev);
6549 6550 6551 6552 6553 6554 6555 6556 6557 6558 6559 6560 6561 6562 6563 6564 6565 6566 6567 6568 6569 6570

		if (vma->vm_flags & VM_READ)
			prot |= PROT_READ;
		if (vma->vm_flags & VM_WRITE)
			prot |= PROT_WRITE;
		if (vma->vm_flags & VM_EXEC)
			prot |= PROT_EXEC;

		if (vma->vm_flags & VM_MAYSHARE)
			flags = MAP_SHARED;
		else
			flags = MAP_PRIVATE;

		if (vma->vm_flags & VM_DENYWRITE)
			flags |= MAP_DENYWRITE;
		if (vma->vm_flags & VM_MAYEXEC)
			flags |= MAP_EXECUTABLE;
		if (vma->vm_flags & VM_LOCKED)
			flags |= MAP_LOCKED;
		if (vma->vm_flags & VM_HUGETLB)
			flags |= MAP_HUGETLB;

6571
		goto got_name;
6572
	} else {
6573 6574 6575 6576 6577 6578
		if (vma->vm_ops && vma->vm_ops->name) {
			name = (char *) vma->vm_ops->name(vma);
			if (name)
				goto cpy_name;
		}

6579
		name = (char *)arch_vma_name(vma);
6580 6581
		if (name)
			goto cpy_name;
6582

6583
		if (vma->vm_start <= vma->vm_mm->start_brk &&
6584
				vma->vm_end >= vma->vm_mm->brk) {
6585 6586
			name = "[heap]";
			goto cpy_name;
6587 6588
		}
		if (vma->vm_start <= vma->vm_mm->start_stack &&
6589
				vma->vm_end >= vma->vm_mm->start_stack) {
6590 6591
			name = "[stack]";
			goto cpy_name;
6592 6593
		}

6594 6595
		name = "//anon";
		goto cpy_name;
6596 6597
	}

6598 6599 6600
cpy_name:
	strlcpy(tmp, name, sizeof(tmp));
	name = tmp;
6601
got_name:
6602 6603 6604 6605 6606 6607 6608 6609
	/*
	 * Since our buffer works in 8 byte units we need to align our string
	 * size to a multiple of 8. However, we must guarantee the tail end is
	 * zero'd out to avoid leaking random bits to userspace.
	 */
	size = strlen(name)+1;
	while (!IS_ALIGNED(size, sizeof(u64)))
		name[size++] = '\0';
6610 6611 6612

	mmap_event->file_name = name;
	mmap_event->file_size = size;
6613 6614 6615 6616
	mmap_event->maj = maj;
	mmap_event->min = min;
	mmap_event->ino = ino;
	mmap_event->ino_generation = gen;
6617 6618
	mmap_event->prot = prot;
	mmap_event->flags = flags;
6619

6620 6621 6622
	if (!(vma->vm_flags & VM_EXEC))
		mmap_event->event_id.header.misc |= PERF_RECORD_MISC_MMAP_DATA;

6623
	mmap_event->event_id.header.size = sizeof(mmap_event->event_id) + size;
6624

6625
	perf_iterate_sb(perf_event_mmap_output,
6626 6627
		       mmap_event,
		       NULL);
6628

6629 6630 6631
	kfree(buf);
}

6632 6633 6634 6635 6636 6637 6638 6639 6640 6641 6642 6643 6644 6645 6646 6647 6648 6649 6650 6651 6652 6653 6654 6655 6656 6657 6658 6659 6660 6661 6662 6663 6664 6665 6666 6667 6668 6669 6670 6671 6672 6673 6674 6675 6676 6677 6678 6679 6680 6681 6682 6683 6684 6685 6686 6687 6688 6689 6690 6691 6692
/*
 * Check whether inode and address range match filter criteria.
 */
static bool perf_addr_filter_match(struct perf_addr_filter *filter,
				     struct file *file, unsigned long offset,
				     unsigned long size)
{
	if (filter->inode != file->f_inode)
		return false;

	if (filter->offset > offset + size)
		return false;

	if (filter->offset + filter->size < offset)
		return false;

	return true;
}

static void __perf_addr_filters_adjust(struct perf_event *event, void *data)
{
	struct perf_addr_filters_head *ifh = perf_event_addr_filters(event);
	struct vm_area_struct *vma = data;
	unsigned long off = vma->vm_pgoff << PAGE_SHIFT, flags;
	struct file *file = vma->vm_file;
	struct perf_addr_filter *filter;
	unsigned int restart = 0, count = 0;

	if (!has_addr_filter(event))
		return;

	if (!file)
		return;

	raw_spin_lock_irqsave(&ifh->lock, flags);
	list_for_each_entry(filter, &ifh->list, entry) {
		if (perf_addr_filter_match(filter, file, off,
					     vma->vm_end - vma->vm_start)) {
			event->addr_filters_offs[count] = vma->vm_start;
			restart++;
		}

		count++;
	}

	if (restart)
		event->addr_filters_gen++;
	raw_spin_unlock_irqrestore(&ifh->lock, flags);

	if (restart)
		perf_event_restart(event);
}

/*
 * Adjust all task's events' filters to the new vma
 */
static void perf_addr_filters_adjust(struct vm_area_struct *vma)
{
	struct perf_event_context *ctx;
	int ctxn;

6693 6694 6695 6696 6697 6698 6699
	/*
	 * Data tracing isn't supported yet and as such there is no need
	 * to keep track of anything that isn't related to executable code:
	 */
	if (!(vma->vm_flags & VM_EXEC))
		return;

6700 6701 6702 6703 6704 6705
	rcu_read_lock();
	for_each_task_context_nr(ctxn) {
		ctx = rcu_dereference(current->perf_event_ctxp[ctxn]);
		if (!ctx)
			continue;

6706
		perf_iterate_ctx(ctx, __perf_addr_filters_adjust, vma, true);
6707 6708 6709 6710
	}
	rcu_read_unlock();
}

6711
void perf_event_mmap(struct vm_area_struct *vma)
6712
{
6713 6714
	struct perf_mmap_event mmap_event;

6715
	if (!atomic_read(&nr_mmap_events))
6716 6717 6718
		return;

	mmap_event = (struct perf_mmap_event){
6719
		.vma	= vma,
6720 6721
		/* .file_name */
		/* .file_size */
6722
		.event_id  = {
6723
			.header = {
6724
				.type = PERF_RECORD_MMAP,
6725
				.misc = PERF_RECORD_MISC_USER,
6726 6727 6728 6729
				/* .size */
			},
			/* .pid */
			/* .tid */
6730 6731
			.start  = vma->vm_start,
			.len    = vma->vm_end - vma->vm_start,
6732
			.pgoff  = (u64)vma->vm_pgoff << PAGE_SHIFT,
6733
		},
6734 6735 6736 6737
		/* .maj (attr_mmap2 only) */
		/* .min (attr_mmap2 only) */
		/* .ino (attr_mmap2 only) */
		/* .ino_generation (attr_mmap2 only) */
6738 6739
		/* .prot (attr_mmap2 only) */
		/* .flags (attr_mmap2 only) */
6740 6741
	};

6742
	perf_addr_filters_adjust(vma);
6743
	perf_event_mmap_event(&mmap_event);
6744 6745
}

A
Alexander Shishkin 已提交
6746 6747 6748 6749 6750 6751 6752 6753 6754 6755 6756 6757 6758 6759 6760 6761 6762 6763 6764 6765 6766 6767 6768 6769 6770 6771 6772 6773 6774 6775 6776 6777 6778 6779
void perf_event_aux_event(struct perf_event *event, unsigned long head,
			  unsigned long size, u64 flags)
{
	struct perf_output_handle handle;
	struct perf_sample_data sample;
	struct perf_aux_event {
		struct perf_event_header	header;
		u64				offset;
		u64				size;
		u64				flags;
	} rec = {
		.header = {
			.type = PERF_RECORD_AUX,
			.misc = 0,
			.size = sizeof(rec),
		},
		.offset		= head,
		.size		= size,
		.flags		= flags,
	};
	int ret;

	perf_event_header__init_id(&rec.header, &sample, event);
	ret = perf_output_begin(&handle, event, rec.header.size);

	if (ret)
		return;

	perf_output_put(&handle, rec);
	perf_event__output_id_sample(event, &handle, &sample);

	perf_output_end(&handle);
}

6780 6781 6782 6783 6784 6785 6786 6787 6788 6789 6790 6791 6792 6793 6794 6795 6796 6797 6798 6799 6800 6801 6802 6803 6804 6805 6806 6807 6808 6809 6810 6811 6812
/*
 * Lost/dropped samples logging
 */
void perf_log_lost_samples(struct perf_event *event, u64 lost)
{
	struct perf_output_handle handle;
	struct perf_sample_data sample;
	int ret;

	struct {
		struct perf_event_header	header;
		u64				lost;
	} lost_samples_event = {
		.header = {
			.type = PERF_RECORD_LOST_SAMPLES,
			.misc = 0,
			.size = sizeof(lost_samples_event),
		},
		.lost		= lost,
	};

	perf_event_header__init_id(&lost_samples_event.header, &sample, event);

	ret = perf_output_begin(&handle, event,
				lost_samples_event.header.size);
	if (ret)
		return;

	perf_output_put(&handle, lost_samples_event);
	perf_event__output_id_sample(event, &handle, &sample);
	perf_output_end(&handle);
}

6813 6814 6815 6816 6817 6818 6819 6820 6821 6822 6823 6824 6825 6826 6827 6828 6829 6830 6831 6832 6833 6834 6835 6836 6837 6838 6839 6840 6841 6842 6843 6844 6845 6846 6847 6848 6849 6850 6851 6852 6853 6854 6855 6856 6857 6858 6859 6860 6861 6862 6863 6864 6865 6866 6867 6868 6869 6870 6871 6872 6873 6874 6875 6876 6877 6878 6879 6880 6881 6882 6883 6884 6885 6886 6887 6888 6889 6890 6891 6892
/*
 * context_switch tracking
 */

struct perf_switch_event {
	struct task_struct	*task;
	struct task_struct	*next_prev;

	struct {
		struct perf_event_header	header;
		u32				next_prev_pid;
		u32				next_prev_tid;
	} event_id;
};

static int perf_event_switch_match(struct perf_event *event)
{
	return event->attr.context_switch;
}

static void perf_event_switch_output(struct perf_event *event, void *data)
{
	struct perf_switch_event *se = data;
	struct perf_output_handle handle;
	struct perf_sample_data sample;
	int ret;

	if (!perf_event_switch_match(event))
		return;

	/* Only CPU-wide events are allowed to see next/prev pid/tid */
	if (event->ctx->task) {
		se->event_id.header.type = PERF_RECORD_SWITCH;
		se->event_id.header.size = sizeof(se->event_id.header);
	} else {
		se->event_id.header.type = PERF_RECORD_SWITCH_CPU_WIDE;
		se->event_id.header.size = sizeof(se->event_id);
		se->event_id.next_prev_pid =
					perf_event_pid(event, se->next_prev);
		se->event_id.next_prev_tid =
					perf_event_tid(event, se->next_prev);
	}

	perf_event_header__init_id(&se->event_id.header, &sample, event);

	ret = perf_output_begin(&handle, event, se->event_id.header.size);
	if (ret)
		return;

	if (event->ctx->task)
		perf_output_put(&handle, se->event_id.header);
	else
		perf_output_put(&handle, se->event_id);

	perf_event__output_id_sample(event, &handle, &sample);

	perf_output_end(&handle);
}

static void perf_event_switch(struct task_struct *task,
			      struct task_struct *next_prev, bool sched_in)
{
	struct perf_switch_event switch_event;

	/* N.B. caller checks nr_switch_events != 0 */

	switch_event = (struct perf_switch_event){
		.task		= task,
		.next_prev	= next_prev,
		.event_id	= {
			.header = {
				/* .type */
				.misc = sched_in ? 0 : PERF_RECORD_MISC_SWITCH_OUT,
				/* .size */
			},
			/* .next_prev_pid */
			/* .next_prev_tid */
		},
	};

6893
	perf_iterate_sb(perf_event_switch_output,
6894 6895 6896 6897
		       &switch_event,
		       NULL);
}

6898 6899 6900 6901
/*
 * IRQ throttle logging
 */

6902
static void perf_log_throttle(struct perf_event *event, int enable)
6903 6904
{
	struct perf_output_handle handle;
6905
	struct perf_sample_data sample;
6906 6907 6908 6909 6910
	int ret;

	struct {
		struct perf_event_header	header;
		u64				time;
6911
		u64				id;
6912
		u64				stream_id;
6913 6914
	} throttle_event = {
		.header = {
6915
			.type = PERF_RECORD_THROTTLE,
6916 6917 6918
			.misc = 0,
			.size = sizeof(throttle_event),
		},
6919
		.time		= perf_event_clock(event),
6920 6921
		.id		= primary_event_id(event),
		.stream_id	= event->id,
6922 6923
	};

6924
	if (enable)
6925
		throttle_event.header.type = PERF_RECORD_UNTHROTTLE;
6926

6927 6928 6929
	perf_event_header__init_id(&throttle_event.header, &sample, event);

	ret = perf_output_begin(&handle, event,
6930
				throttle_event.header.size);
6931 6932 6933 6934
	if (ret)
		return;

	perf_output_put(&handle, throttle_event);
6935
	perf_event__output_id_sample(event, &handle, &sample);
6936 6937 6938
	perf_output_end(&handle);
}

6939 6940 6941 6942 6943 6944 6945 6946 6947 6948 6949 6950 6951 6952 6953 6954 6955 6956 6957 6958 6959 6960 6961 6962 6963 6964 6965 6966 6967 6968 6969 6970 6971 6972 6973 6974
static void perf_log_itrace_start(struct perf_event *event)
{
	struct perf_output_handle handle;
	struct perf_sample_data sample;
	struct perf_aux_event {
		struct perf_event_header        header;
		u32				pid;
		u32				tid;
	} rec;
	int ret;

	if (event->parent)
		event = event->parent;

	if (!(event->pmu->capabilities & PERF_PMU_CAP_ITRACE) ||
	    event->hw.itrace_started)
		return;

	rec.header.type	= PERF_RECORD_ITRACE_START;
	rec.header.misc	= 0;
	rec.header.size	= sizeof(rec);
	rec.pid	= perf_event_pid(event, current);
	rec.tid	= perf_event_tid(event, current);

	perf_event_header__init_id(&rec.header, &sample, event);
	ret = perf_output_begin(&handle, event, rec.header.size);

	if (ret)
		return;

	perf_output_put(&handle, rec);
	perf_event__output_id_sample(event, &handle, &sample);

	perf_output_end(&handle);
}

6975
/*
6976
 * Generic event overflow handling, sampling.
6977 6978
 */

6979
static int __perf_event_overflow(struct perf_event *event,
6980 6981
				   int throttle, struct perf_sample_data *data,
				   struct pt_regs *regs)
6982
{
6983 6984
	int events = atomic_read(&event->event_limit);
	struct hw_perf_event *hwc = &event->hw;
6985
	u64 seq;
6986 6987
	int ret = 0;

6988 6989 6990 6991 6992 6993 6994
	/*
	 * Non-sampling counters might still use the PMI to fold short
	 * hardware counters, ignore those.
	 */
	if (unlikely(!is_sampling_event(event)))
		return 0;

6995 6996 6997 6998 6999 7000 7001 7002 7003
	seq = __this_cpu_read(perf_throttled_seq);
	if (seq != hwc->interrupts_seq) {
		hwc->interrupts_seq = seq;
		hwc->interrupts = 1;
	} else {
		hwc->interrupts++;
		if (unlikely(throttle
			     && hwc->interrupts >= max_samples_per_tick)) {
			__this_cpu_inc(perf_throttled_count);
7004
			tick_dep_set_cpu(smp_processor_id(), TICK_DEP_BIT_PERF_EVENTS);
P
Peter Zijlstra 已提交
7005 7006
			hwc->interrupts = MAX_INTERRUPTS;
			perf_log_throttle(event, 0);
7007 7008
			ret = 1;
		}
7009
	}
7010

7011
	if (event->attr.freq) {
P
Peter Zijlstra 已提交
7012
		u64 now = perf_clock();
7013
		s64 delta = now - hwc->freq_time_stamp;
7014

7015
		hwc->freq_time_stamp = now;
7016

7017
		if (delta > 0 && delta < 2*TICK_NSEC)
7018
			perf_adjust_period(event, delta, hwc->last_period, true);
7019 7020
	}

7021 7022
	/*
	 * XXX event_limit might not quite work as expected on inherited
7023
	 * events
7024 7025
	 */

7026 7027
	event->pending_kill = POLL_IN;
	if (events && atomic_dec_and_test(&event->event_limit)) {
7028
		ret = 1;
7029
		event->pending_kill = POLL_HUP;
7030 7031
		event->pending_disable = 1;
		irq_work_queue(&event->pending);
7032 7033
	}

7034
	event->overflow_handler(event, data, regs);
7035

7036
	if (*perf_event_fasync(event) && event->pending_kill) {
7037 7038
		event->pending_wakeup = 1;
		irq_work_queue(&event->pending);
P
Peter Zijlstra 已提交
7039 7040
	}

7041
	return ret;
7042 7043
}

7044
int perf_event_overflow(struct perf_event *event,
7045 7046
			  struct perf_sample_data *data,
			  struct pt_regs *regs)
7047
{
7048
	return __perf_event_overflow(event, 1, data, regs);
7049 7050
}

7051
/*
7052
 * Generic software event infrastructure
7053 7054
 */

7055 7056 7057 7058 7059 7060 7061 7062 7063 7064 7065
struct swevent_htable {
	struct swevent_hlist		*swevent_hlist;
	struct mutex			hlist_mutex;
	int				hlist_refcount;

	/* Recursion avoidance in each contexts */
	int				recursion[PERF_NR_CONTEXTS];
};

static DEFINE_PER_CPU(struct swevent_htable, swevent_htable);

7066
/*
7067 7068
 * We directly increment event->count and keep a second value in
 * event->hw.period_left to count intervals. This period event
7069 7070 7071 7072
 * is kept in the range [-sample_period, 0] so that we can use the
 * sign as trigger.
 */

7073
u64 perf_swevent_set_period(struct perf_event *event)
7074
{
7075
	struct hw_perf_event *hwc = &event->hw;
7076 7077 7078 7079 7080
	u64 period = hwc->last_period;
	u64 nr, offset;
	s64 old, val;

	hwc->last_period = hwc->sample_period;
7081 7082

again:
7083
	old = val = local64_read(&hwc->period_left);
7084 7085
	if (val < 0)
		return 0;
7086

7087 7088 7089
	nr = div64_u64(period + val, period);
	offset = nr * period;
	val -= offset;
7090
	if (local64_cmpxchg(&hwc->period_left, old, val) != old)
7091
		goto again;
7092

7093
	return nr;
7094 7095
}

7096
static void perf_swevent_overflow(struct perf_event *event, u64 overflow,
7097
				    struct perf_sample_data *data,
7098
				    struct pt_regs *regs)
7099
{
7100
	struct hw_perf_event *hwc = &event->hw;
7101
	int throttle = 0;
7102

7103 7104
	if (!overflow)
		overflow = perf_swevent_set_period(event);
7105

7106 7107
	if (hwc->interrupts == MAX_INTERRUPTS)
		return;
7108

7109
	for (; overflow; overflow--) {
7110
		if (__perf_event_overflow(event, throttle,
7111
					    data, regs)) {
7112 7113 7114 7115 7116 7117
			/*
			 * We inhibit the overflow from happening when
			 * hwc->interrupts == MAX_INTERRUPTS.
			 */
			break;
		}
7118
		throttle = 1;
7119
	}
7120 7121
}

P
Peter Zijlstra 已提交
7122
static void perf_swevent_event(struct perf_event *event, u64 nr,
7123
			       struct perf_sample_data *data,
7124
			       struct pt_regs *regs)
7125
{
7126
	struct hw_perf_event *hwc = &event->hw;
7127

7128
	local64_add(nr, &event->count);
7129

7130 7131 7132
	if (!regs)
		return;

7133
	if (!is_sampling_event(event))
7134
		return;
7135

7136 7137 7138 7139 7140 7141
	if ((event->attr.sample_type & PERF_SAMPLE_PERIOD) && !event->attr.freq) {
		data->period = nr;
		return perf_swevent_overflow(event, 1, data, regs);
	} else
		data->period = event->hw.last_period;

7142
	if (nr == 1 && hwc->sample_period == 1 && !event->attr.freq)
7143
		return perf_swevent_overflow(event, 1, data, regs);
7144

7145
	if (local64_add_negative(nr, &hwc->period_left))
7146
		return;
7147

7148
	perf_swevent_overflow(event, 0, data, regs);
7149 7150
}

7151 7152 7153
static int perf_exclude_event(struct perf_event *event,
			      struct pt_regs *regs)
{
P
Peter Zijlstra 已提交
7154
	if (event->hw.state & PERF_HES_STOPPED)
7155
		return 1;
P
Peter Zijlstra 已提交
7156

7157 7158 7159 7160 7161 7162 7163 7164 7165 7166 7167
	if (regs) {
		if (event->attr.exclude_user && user_mode(regs))
			return 1;

		if (event->attr.exclude_kernel && !user_mode(regs))
			return 1;
	}

	return 0;
}

7168
static int perf_swevent_match(struct perf_event *event,
P
Peter Zijlstra 已提交
7169
				enum perf_type_id type,
L
Li Zefan 已提交
7170 7171 7172
				u32 event_id,
				struct perf_sample_data *data,
				struct pt_regs *regs)
7173
{
7174
	if (event->attr.type != type)
7175
		return 0;
7176

7177
	if (event->attr.config != event_id)
7178 7179
		return 0;

7180 7181
	if (perf_exclude_event(event, regs))
		return 0;
7182 7183 7184 7185

	return 1;
}

7186 7187 7188 7189 7190 7191 7192
static inline u64 swevent_hash(u64 type, u32 event_id)
{
	u64 val = event_id | (type << 32);

	return hash_64(val, SWEVENT_HLIST_BITS);
}

7193 7194
static inline struct hlist_head *
__find_swevent_head(struct swevent_hlist *hlist, u64 type, u32 event_id)
7195
{
7196 7197 7198 7199
	u64 hash = swevent_hash(type, event_id);

	return &hlist->heads[hash];
}
7200

7201 7202
/* For the read side: events when they trigger */
static inline struct hlist_head *
7203
find_swevent_head_rcu(struct swevent_htable *swhash, u64 type, u32 event_id)
7204 7205
{
	struct swevent_hlist *hlist;
7206

7207
	hlist = rcu_dereference(swhash->swevent_hlist);
7208 7209 7210
	if (!hlist)
		return NULL;

7211 7212 7213 7214 7215
	return __find_swevent_head(hlist, type, event_id);
}

/* For the event head insertion and removal in the hlist */
static inline struct hlist_head *
7216
find_swevent_head(struct swevent_htable *swhash, struct perf_event *event)
7217 7218 7219 7220 7221 7222 7223 7224 7225 7226
{
	struct swevent_hlist *hlist;
	u32 event_id = event->attr.config;
	u64 type = event->attr.type;

	/*
	 * Event scheduling is always serialized against hlist allocation
	 * and release. Which makes the protected version suitable here.
	 * The context lock guarantees that.
	 */
7227
	hlist = rcu_dereference_protected(swhash->swevent_hlist,
7228 7229 7230 7231 7232
					  lockdep_is_held(&event->ctx->lock));
	if (!hlist)
		return NULL;

	return __find_swevent_head(hlist, type, event_id);
7233 7234 7235
}

static void do_perf_sw_event(enum perf_type_id type, u32 event_id,
7236
				    u64 nr,
7237 7238
				    struct perf_sample_data *data,
				    struct pt_regs *regs)
7239
{
7240
	struct swevent_htable *swhash = this_cpu_ptr(&swevent_htable);
7241
	struct perf_event *event;
7242
	struct hlist_head *head;
7243

7244
	rcu_read_lock();
7245
	head = find_swevent_head_rcu(swhash, type, event_id);
7246 7247 7248
	if (!head)
		goto end;

7249
	hlist_for_each_entry_rcu(event, head, hlist_entry) {
L
Li Zefan 已提交
7250
		if (perf_swevent_match(event, type, event_id, data, regs))
7251
			perf_swevent_event(event, nr, data, regs);
7252
	}
7253 7254
end:
	rcu_read_unlock();
7255 7256
}

7257 7258
DEFINE_PER_CPU(struct pt_regs, __perf_regs[4]);

7259
int perf_swevent_get_recursion_context(void)
P
Peter Zijlstra 已提交
7260
{
7261
	struct swevent_htable *swhash = this_cpu_ptr(&swevent_htable);
P
Peter Zijlstra 已提交
7262

7263
	return get_recursion_context(swhash->recursion);
P
Peter Zijlstra 已提交
7264
}
I
Ingo Molnar 已提交
7265
EXPORT_SYMBOL_GPL(perf_swevent_get_recursion_context);
P
Peter Zijlstra 已提交
7266

7267
void perf_swevent_put_recursion_context(int rctx)
7268
{
7269
	struct swevent_htable *swhash = this_cpu_ptr(&swevent_htable);
7270

7271
	put_recursion_context(swhash->recursion, rctx);
7272
}
7273

7274
void ___perf_sw_event(u32 event_id, u64 nr, struct pt_regs *regs, u64 addr)
7275
{
7276
	struct perf_sample_data data;
7277

7278
	if (WARN_ON_ONCE(!regs))
7279
		return;
7280

7281
	perf_sample_data_init(&data, addr, 0);
7282
	do_perf_sw_event(PERF_TYPE_SOFTWARE, event_id, nr, &data, regs);
7283 7284 7285 7286 7287 7288 7289 7290 7291 7292 7293 7294
}

void __perf_sw_event(u32 event_id, u64 nr, struct pt_regs *regs, u64 addr)
{
	int rctx;

	preempt_disable_notrace();
	rctx = perf_swevent_get_recursion_context();
	if (unlikely(rctx < 0))
		goto fail;

	___perf_sw_event(event_id, nr, regs, addr);
7295 7296

	perf_swevent_put_recursion_context(rctx);
7297
fail:
7298
	preempt_enable_notrace();
7299 7300
}

7301
static void perf_swevent_read(struct perf_event *event)
7302 7303 7304
{
}

P
Peter Zijlstra 已提交
7305
static int perf_swevent_add(struct perf_event *event, int flags)
7306
{
7307
	struct swevent_htable *swhash = this_cpu_ptr(&swevent_htable);
7308
	struct hw_perf_event *hwc = &event->hw;
7309 7310
	struct hlist_head *head;

7311
	if (is_sampling_event(event)) {
7312
		hwc->last_period = hwc->sample_period;
7313
		perf_swevent_set_period(event);
7314
	}
7315

P
Peter Zijlstra 已提交
7316 7317
	hwc->state = !(flags & PERF_EF_START);

7318
	head = find_swevent_head(swhash, event);
P
Peter Zijlstra 已提交
7319
	if (WARN_ON_ONCE(!head))
7320 7321 7322
		return -EINVAL;

	hlist_add_head_rcu(&event->hlist_entry, head);
7323
	perf_event_update_userpage(event);
7324

7325 7326 7327
	return 0;
}

P
Peter Zijlstra 已提交
7328
static void perf_swevent_del(struct perf_event *event, int flags)
7329
{
7330
	hlist_del_rcu(&event->hlist_entry);
7331 7332
}

P
Peter Zijlstra 已提交
7333
static void perf_swevent_start(struct perf_event *event, int flags)
7334
{
P
Peter Zijlstra 已提交
7335
	event->hw.state = 0;
7336
}
I
Ingo Molnar 已提交
7337

P
Peter Zijlstra 已提交
7338
static void perf_swevent_stop(struct perf_event *event, int flags)
7339
{
P
Peter Zijlstra 已提交
7340
	event->hw.state = PERF_HES_STOPPED;
7341 7342
}

7343 7344
/* Deref the hlist from the update side */
static inline struct swevent_hlist *
7345
swevent_hlist_deref(struct swevent_htable *swhash)
7346
{
7347 7348
	return rcu_dereference_protected(swhash->swevent_hlist,
					 lockdep_is_held(&swhash->hlist_mutex));
7349 7350
}

7351
static void swevent_hlist_release(struct swevent_htable *swhash)
7352
{
7353
	struct swevent_hlist *hlist = swevent_hlist_deref(swhash);
7354

7355
	if (!hlist)
7356 7357
		return;

7358
	RCU_INIT_POINTER(swhash->swevent_hlist, NULL);
7359
	kfree_rcu(hlist, rcu_head);
7360 7361
}

7362
static void swevent_hlist_put_cpu(int cpu)
7363
{
7364
	struct swevent_htable *swhash = &per_cpu(swevent_htable, cpu);
7365

7366
	mutex_lock(&swhash->hlist_mutex);
7367

7368 7369
	if (!--swhash->hlist_refcount)
		swevent_hlist_release(swhash);
7370

7371
	mutex_unlock(&swhash->hlist_mutex);
7372 7373
}

7374
static void swevent_hlist_put(void)
7375 7376 7377 7378
{
	int cpu;

	for_each_possible_cpu(cpu)
7379
		swevent_hlist_put_cpu(cpu);
7380 7381
}

7382
static int swevent_hlist_get_cpu(int cpu)
7383
{
7384
	struct swevent_htable *swhash = &per_cpu(swevent_htable, cpu);
7385 7386
	int err = 0;

7387 7388
	mutex_lock(&swhash->hlist_mutex);
	if (!swevent_hlist_deref(swhash) && cpu_online(cpu)) {
7389 7390 7391 7392 7393 7394 7395
		struct swevent_hlist *hlist;

		hlist = kzalloc(sizeof(*hlist), GFP_KERNEL);
		if (!hlist) {
			err = -ENOMEM;
			goto exit;
		}
7396
		rcu_assign_pointer(swhash->swevent_hlist, hlist);
7397
	}
7398
	swhash->hlist_refcount++;
P
Peter Zijlstra 已提交
7399
exit:
7400
	mutex_unlock(&swhash->hlist_mutex);
7401 7402 7403 7404

	return err;
}

7405
static int swevent_hlist_get(void)
7406
{
7407
	int err, cpu, failed_cpu;
7408 7409 7410

	get_online_cpus();
	for_each_possible_cpu(cpu) {
7411
		err = swevent_hlist_get_cpu(cpu);
7412 7413 7414 7415 7416 7417 7418 7419
		if (err) {
			failed_cpu = cpu;
			goto fail;
		}
	}
	put_online_cpus();

	return 0;
P
Peter Zijlstra 已提交
7420
fail:
7421 7422 7423
	for_each_possible_cpu(cpu) {
		if (cpu == failed_cpu)
			break;
7424
		swevent_hlist_put_cpu(cpu);
7425 7426 7427 7428 7429 7430
	}

	put_online_cpus();
	return err;
}

7431
struct static_key perf_swevent_enabled[PERF_COUNT_SW_MAX];
7432

7433 7434 7435
static void sw_perf_event_destroy(struct perf_event *event)
{
	u64 event_id = event->attr.config;
7436

7437 7438
	WARN_ON(event->parent);

7439
	static_key_slow_dec(&perf_swevent_enabled[event_id]);
7440
	swevent_hlist_put();
7441 7442 7443 7444
}

static int perf_swevent_init(struct perf_event *event)
{
7445
	u64 event_id = event->attr.config;
7446 7447 7448 7449

	if (event->attr.type != PERF_TYPE_SOFTWARE)
		return -ENOENT;

7450 7451 7452 7453 7454 7455
	/*
	 * no branch sampling for software events
	 */
	if (has_branch_stack(event))
		return -EOPNOTSUPP;

7456 7457 7458 7459 7460 7461 7462 7463 7464
	switch (event_id) {
	case PERF_COUNT_SW_CPU_CLOCK:
	case PERF_COUNT_SW_TASK_CLOCK:
		return -ENOENT;

	default:
		break;
	}

7465
	if (event_id >= PERF_COUNT_SW_MAX)
7466 7467 7468 7469 7470
		return -ENOENT;

	if (!event->parent) {
		int err;

7471
		err = swevent_hlist_get();
7472 7473 7474
		if (err)
			return err;

7475
		static_key_slow_inc(&perf_swevent_enabled[event_id]);
7476 7477 7478 7479 7480 7481 7482
		event->destroy = sw_perf_event_destroy;
	}

	return 0;
}

static struct pmu perf_swevent = {
7483
	.task_ctx_nr	= perf_sw_context,
7484

7485 7486
	.capabilities	= PERF_PMU_CAP_NO_NMI,

7487
	.event_init	= perf_swevent_init,
P
Peter Zijlstra 已提交
7488 7489 7490 7491
	.add		= perf_swevent_add,
	.del		= perf_swevent_del,
	.start		= perf_swevent_start,
	.stop		= perf_swevent_stop,
7492 7493 7494
	.read		= perf_swevent_read,
};

7495 7496
#ifdef CONFIG_EVENT_TRACING

7497 7498 7499
static int perf_tp_filter_match(struct perf_event *event,
				struct perf_sample_data *data)
{
7500
	void *record = data->raw->frag.data;
7501

7502 7503 7504 7505
	/* only top level events have filters set */
	if (event->parent)
		event = event->parent;

7506 7507 7508 7509 7510 7511 7512 7513 7514
	if (likely(!event->filter) || filter_match_preds(event->filter, record))
		return 1;
	return 0;
}

static int perf_tp_event_match(struct perf_event *event,
				struct perf_sample_data *data,
				struct pt_regs *regs)
{
7515 7516
	if (event->hw.state & PERF_HES_STOPPED)
		return 0;
7517 7518 7519 7520
	/*
	 * All tracepoints are from kernel-space.
	 */
	if (event->attr.exclude_kernel)
7521 7522 7523 7524 7525 7526 7527 7528
		return 0;

	if (!perf_tp_filter_match(event, data))
		return 0;

	return 1;
}

7529 7530 7531 7532 7533 7534 7535 7536 7537 7538 7539 7540 7541 7542 7543 7544 7545 7546 7547
void perf_trace_run_bpf_submit(void *raw_data, int size, int rctx,
			       struct trace_event_call *call, u64 count,
			       struct pt_regs *regs, struct hlist_head *head,
			       struct task_struct *task)
{
	struct bpf_prog *prog = call->prog;

	if (prog) {
		*(struct pt_regs **)raw_data = regs;
		if (!trace_call_bpf(prog, raw_data) || hlist_empty(head)) {
			perf_swevent_put_recursion_context(rctx);
			return;
		}
	}
	perf_tp_event(call->event.type, count, raw_data, size, regs, head,
		      rctx, task);
}
EXPORT_SYMBOL_GPL(perf_trace_run_bpf_submit);

7548
void perf_tp_event(u16 event_type, u64 count, void *record, int entry_size,
7549 7550
		   struct pt_regs *regs, struct hlist_head *head, int rctx,
		   struct task_struct *task)
7551 7552
{
	struct perf_sample_data data;
7553 7554
	struct perf_event *event;

7555
	struct perf_raw_record raw = {
7556 7557 7558 7559
		.frag = {
			.size = entry_size,
			.data = record,
		},
7560 7561
	};

7562
	perf_sample_data_init(&data, 0, 0);
7563 7564
	data.raw = &raw;

7565 7566
	perf_trace_buf_update(record, event_type);

7567
	hlist_for_each_entry_rcu(event, head, hlist_entry) {
7568
		if (perf_tp_event_match(event, &data, regs))
7569
			perf_swevent_event(event, count, &data, regs);
7570
	}
7571

7572 7573 7574 7575 7576 7577 7578 7579 7580 7581 7582 7583 7584 7585 7586 7587 7588 7589 7590 7591 7592 7593 7594 7595 7596
	/*
	 * If we got specified a target task, also iterate its context and
	 * deliver this event there too.
	 */
	if (task && task != current) {
		struct perf_event_context *ctx;
		struct trace_entry *entry = record;

		rcu_read_lock();
		ctx = rcu_dereference(task->perf_event_ctxp[perf_sw_context]);
		if (!ctx)
			goto unlock;

		list_for_each_entry_rcu(event, &ctx->event_list, event_entry) {
			if (event->attr.type != PERF_TYPE_TRACEPOINT)
				continue;
			if (event->attr.config != entry->type)
				continue;
			if (perf_tp_event_match(event, &data, regs))
				perf_swevent_event(event, count, &data, regs);
		}
unlock:
		rcu_read_unlock();
	}

7597
	perf_swevent_put_recursion_context(rctx);
7598 7599 7600
}
EXPORT_SYMBOL_GPL(perf_tp_event);

7601
static void tp_perf_event_destroy(struct perf_event *event)
7602
{
7603
	perf_trace_destroy(event);
7604 7605
}

7606
static int perf_tp_event_init(struct perf_event *event)
7607
{
7608 7609
	int err;

7610 7611 7612
	if (event->attr.type != PERF_TYPE_TRACEPOINT)
		return -ENOENT;

7613 7614 7615 7616 7617 7618
	/*
	 * no branch sampling for tracepoint events
	 */
	if (has_branch_stack(event))
		return -EOPNOTSUPP;

7619 7620
	err = perf_trace_init(event);
	if (err)
7621
		return err;
7622

7623
	event->destroy = tp_perf_event_destroy;
7624

7625 7626 7627 7628
	return 0;
}

static struct pmu perf_tracepoint = {
7629 7630
	.task_ctx_nr	= perf_sw_context,

7631
	.event_init	= perf_tp_event_init,
P
Peter Zijlstra 已提交
7632 7633 7634 7635
	.add		= perf_trace_add,
	.del		= perf_trace_del,
	.start		= perf_swevent_start,
	.stop		= perf_swevent_stop,
7636 7637 7638 7639 7640
	.read		= perf_swevent_read,
};

static inline void perf_tp_register(void)
{
P
Peter Zijlstra 已提交
7641
	perf_pmu_register(&perf_tracepoint, "tracepoint", PERF_TYPE_TRACEPOINT);
7642
}
L
Li Zefan 已提交
7643 7644 7645 7646 7647 7648

static void perf_event_free_filter(struct perf_event *event)
{
	ftrace_profile_free_filter(event);
}

7649 7650
static int perf_event_set_bpf_prog(struct perf_event *event, u32 prog_fd)
{
7651
	bool is_kprobe, is_tracepoint;
7652 7653 7654 7655 7656 7657 7658 7659
	struct bpf_prog *prog;

	if (event->attr.type != PERF_TYPE_TRACEPOINT)
		return -EINVAL;

	if (event->tp_event->prog)
		return -EEXIST;

7660 7661 7662 7663
	is_kprobe = event->tp_event->flags & TRACE_EVENT_FL_UKPROBE;
	is_tracepoint = event->tp_event->flags & TRACE_EVENT_FL_TRACEPOINT;
	if (!is_kprobe && !is_tracepoint)
		/* bpf programs can only be attached to u/kprobe or tracepoint */
7664 7665 7666 7667 7668 7669
		return -EINVAL;

	prog = bpf_prog_get(prog_fd);
	if (IS_ERR(prog))
		return PTR_ERR(prog);

7670 7671
	if ((is_kprobe && prog->type != BPF_PROG_TYPE_KPROBE) ||
	    (is_tracepoint && prog->type != BPF_PROG_TYPE_TRACEPOINT)) {
7672 7673 7674 7675 7676
		/* valid fd, but invalid bpf program type */
		bpf_prog_put(prog);
		return -EINVAL;
	}

7677 7678 7679 7680 7681 7682 7683 7684
	if (is_tracepoint) {
		int off = trace_event_get_offsets(event->tp_event);

		if (prog->aux->max_ctx_offset > off) {
			bpf_prog_put(prog);
			return -EACCES;
		}
	}
7685 7686 7687 7688 7689 7690 7691 7692 7693 7694 7695 7696 7697 7698 7699
	event->tp_event->prog = prog;

	return 0;
}

static void perf_event_free_bpf_prog(struct perf_event *event)
{
	struct bpf_prog *prog;

	if (!event->tp_event)
		return;

	prog = event->tp_event->prog;
	if (prog) {
		event->tp_event->prog = NULL;
7700
		bpf_prog_put(prog);
7701 7702 7703
	}
}

7704
#else
L
Li Zefan 已提交
7705

7706
static inline void perf_tp_register(void)
7707 7708
{
}
L
Li Zefan 已提交
7709 7710 7711 7712 7713

static void perf_event_free_filter(struct perf_event *event)
{
}

7714 7715 7716 7717 7718 7719 7720 7721
static int perf_event_set_bpf_prog(struct perf_event *event, u32 prog_fd)
{
	return -ENOENT;
}

static void perf_event_free_bpf_prog(struct perf_event *event)
{
}
7722
#endif /* CONFIG_EVENT_TRACING */
7723

7724
#ifdef CONFIG_HAVE_HW_BREAKPOINT
7725
void perf_bp_event(struct perf_event *bp, void *data)
7726
{
7727 7728 7729
	struct perf_sample_data sample;
	struct pt_regs *regs = data;

7730
	perf_sample_data_init(&sample, bp->attr.bp_addr, 0);
7731

P
Peter Zijlstra 已提交
7732
	if (!bp->hw.state && !perf_exclude_event(bp, regs))
7733
		perf_swevent_event(bp, 1, &sample, regs);
7734 7735 7736
}
#endif

7737 7738 7739 7740 7741 7742 7743 7744 7745 7746 7747 7748 7749 7750 7751 7752 7753 7754 7755 7756 7757 7758 7759 7760 7761 7762 7763 7764 7765 7766 7767 7768 7769 7770 7771 7772 7773 7774 7775 7776 7777 7778 7779 7780 7781 7782 7783 7784 7785 7786 7787 7788 7789 7790 7791 7792 7793 7794 7795 7796 7797 7798 7799 7800 7801 7802 7803 7804 7805 7806 7807 7808 7809 7810 7811 7812 7813 7814 7815 7816 7817 7818 7819 7820 7821 7822 7823 7824 7825 7826 7827 7828 7829 7830 7831 7832 7833 7834 7835 7836 7837 7838 7839 7840 7841 7842 7843 7844 7845 7846 7847 7848 7849 7850 7851
/*
 * Allocate a new address filter
 */
static struct perf_addr_filter *
perf_addr_filter_new(struct perf_event *event, struct list_head *filters)
{
	int node = cpu_to_node(event->cpu == -1 ? 0 : event->cpu);
	struct perf_addr_filter *filter;

	filter = kzalloc_node(sizeof(*filter), GFP_KERNEL, node);
	if (!filter)
		return NULL;

	INIT_LIST_HEAD(&filter->entry);
	list_add_tail(&filter->entry, filters);

	return filter;
}

static void free_filters_list(struct list_head *filters)
{
	struct perf_addr_filter *filter, *iter;

	list_for_each_entry_safe(filter, iter, filters, entry) {
		if (filter->inode)
			iput(filter->inode);
		list_del(&filter->entry);
		kfree(filter);
	}
}

/*
 * Free existing address filters and optionally install new ones
 */
static void perf_addr_filters_splice(struct perf_event *event,
				     struct list_head *head)
{
	unsigned long flags;
	LIST_HEAD(list);

	if (!has_addr_filter(event))
		return;

	/* don't bother with children, they don't have their own filters */
	if (event->parent)
		return;

	raw_spin_lock_irqsave(&event->addr_filters.lock, flags);

	list_splice_init(&event->addr_filters.list, &list);
	if (head)
		list_splice(head, &event->addr_filters.list);

	raw_spin_unlock_irqrestore(&event->addr_filters.lock, flags);

	free_filters_list(&list);
}

/*
 * Scan through mm's vmas and see if one of them matches the
 * @filter; if so, adjust filter's address range.
 * Called with mm::mmap_sem down for reading.
 */
static unsigned long perf_addr_filter_apply(struct perf_addr_filter *filter,
					    struct mm_struct *mm)
{
	struct vm_area_struct *vma;

	for (vma = mm->mmap; vma; vma = vma->vm_next) {
		struct file *file = vma->vm_file;
		unsigned long off = vma->vm_pgoff << PAGE_SHIFT;
		unsigned long vma_size = vma->vm_end - vma->vm_start;

		if (!file)
			continue;

		if (!perf_addr_filter_match(filter, file, off, vma_size))
			continue;

		return vma->vm_start;
	}

	return 0;
}

/*
 * Update event's address range filters based on the
 * task's existing mappings, if any.
 */
static void perf_event_addr_filters_apply(struct perf_event *event)
{
	struct perf_addr_filters_head *ifh = perf_event_addr_filters(event);
	struct task_struct *task = READ_ONCE(event->ctx->task);
	struct perf_addr_filter *filter;
	struct mm_struct *mm = NULL;
	unsigned int count = 0;
	unsigned long flags;

	/*
	 * We may observe TASK_TOMBSTONE, which means that the event tear-down
	 * will stop on the parent's child_mutex that our caller is also holding
	 */
	if (task == TASK_TOMBSTONE)
		return;

	mm = get_task_mm(event->ctx->task);
	if (!mm)
		goto restart;

	down_read(&mm->mmap_sem);

	raw_spin_lock_irqsave(&ifh->lock, flags);
	list_for_each_entry(filter, &ifh->list, entry) {
		event->addr_filters_offs[count] = 0;

7852 7853 7854 7855 7856
		/*
		 * Adjust base offset if the filter is associated to a binary
		 * that needs to be mapped:
		 */
		if (filter->inode)
7857 7858 7859 7860 7861 7862 7863 7864 7865 7866 7867 7868 7869 7870 7871 7872 7873 7874 7875 7876 7877 7878 7879 7880 7881 7882 7883 7884 7885 7886 7887 7888 7889 7890 7891 7892 7893 7894 7895 7896 7897 7898 7899 7900 7901 7902 7903 7904 7905 7906 7907 7908 7909 7910 7911 7912 7913 7914 7915 7916 7917 7918 7919 7920 7921 7922 7923 7924 7925 7926 7927 7928 7929 7930 7931 7932 7933 7934 7935 7936 7937 7938 7939 7940 7941 7942 7943 7944 7945 7946 7947 7948 7949 7950 7951 7952 7953 7954 7955 7956 7957 7958 7959 7960 7961 7962 7963 7964 7965 7966 7967 7968 7969 7970 7971 7972 7973 7974 7975 7976 7977 7978 7979 7980 7981 7982 7983 7984 7985 7986
			event->addr_filters_offs[count] =
				perf_addr_filter_apply(filter, mm);

		count++;
	}

	event->addr_filters_gen++;
	raw_spin_unlock_irqrestore(&ifh->lock, flags);

	up_read(&mm->mmap_sem);

	mmput(mm);

restart:
	perf_event_restart(event);
}

/*
 * Address range filtering: limiting the data to certain
 * instruction address ranges. Filters are ioctl()ed to us from
 * userspace as ascii strings.
 *
 * Filter string format:
 *
 * ACTION RANGE_SPEC
 * where ACTION is one of the
 *  * "filter": limit the trace to this region
 *  * "start": start tracing from this address
 *  * "stop": stop tracing at this address/region;
 * RANGE_SPEC is
 *  * for kernel addresses: <start address>[/<size>]
 *  * for object files:     <start address>[/<size>]@</path/to/object/file>
 *
 * if <size> is not specified, the range is treated as a single address.
 */
enum {
	IF_ACT_FILTER,
	IF_ACT_START,
	IF_ACT_STOP,
	IF_SRC_FILE,
	IF_SRC_KERNEL,
	IF_SRC_FILEADDR,
	IF_SRC_KERNELADDR,
};

enum {
	IF_STATE_ACTION = 0,
	IF_STATE_SOURCE,
	IF_STATE_END,
};

static const match_table_t if_tokens = {
	{ IF_ACT_FILTER,	"filter" },
	{ IF_ACT_START,		"start" },
	{ IF_ACT_STOP,		"stop" },
	{ IF_SRC_FILE,		"%u/%u@%s" },
	{ IF_SRC_KERNEL,	"%u/%u" },
	{ IF_SRC_FILEADDR,	"%u@%s" },
	{ IF_SRC_KERNELADDR,	"%u" },
};

/*
 * Address filter string parser
 */
static int
perf_event_parse_addr_filter(struct perf_event *event, char *fstr,
			     struct list_head *filters)
{
	struct perf_addr_filter *filter = NULL;
	char *start, *orig, *filename = NULL;
	struct path path;
	substring_t args[MAX_OPT_ARGS];
	int state = IF_STATE_ACTION, token;
	unsigned int kernel = 0;
	int ret = -EINVAL;

	orig = fstr = kstrdup(fstr, GFP_KERNEL);
	if (!fstr)
		return -ENOMEM;

	while ((start = strsep(&fstr, " ,\n")) != NULL) {
		ret = -EINVAL;

		if (!*start)
			continue;

		/* filter definition begins */
		if (state == IF_STATE_ACTION) {
			filter = perf_addr_filter_new(event, filters);
			if (!filter)
				goto fail;
		}

		token = match_token(start, if_tokens, args);
		switch (token) {
		case IF_ACT_FILTER:
		case IF_ACT_START:
			filter->filter = 1;

		case IF_ACT_STOP:
			if (state != IF_STATE_ACTION)
				goto fail;

			state = IF_STATE_SOURCE;
			break;

		case IF_SRC_KERNELADDR:
		case IF_SRC_KERNEL:
			kernel = 1;

		case IF_SRC_FILEADDR:
		case IF_SRC_FILE:
			if (state != IF_STATE_SOURCE)
				goto fail;

			if (token == IF_SRC_FILE || token == IF_SRC_KERNEL)
				filter->range = 1;

			*args[0].to = 0;
			ret = kstrtoul(args[0].from, 0, &filter->offset);
			if (ret)
				goto fail;

			if (filter->range) {
				*args[1].to = 0;
				ret = kstrtoul(args[1].from, 0, &filter->size);
				if (ret)
					goto fail;
			}

7987 7988 7989 7990
			if (token == IF_SRC_FILE || token == IF_SRC_FILEADDR) {
				int fpos = filter->range ? 2 : 1;

				filename = match_strdup(&args[fpos]);
7991 7992 7993 7994 7995 7996 7997 7998 7999 8000 8001 8002 8003 8004 8005 8006 8007 8008 8009 8010 8011 8012 8013 8014 8015 8016 8017 8018 8019 8020 8021 8022 8023 8024 8025 8026 8027 8028 8029 8030 8031 8032 8033 8034 8035 8036 8037 8038 8039 8040 8041 8042 8043 8044 8045 8046 8047 8048 8049 8050 8051 8052 8053 8054 8055 8056 8057 8058 8059 8060 8061 8062 8063 8064 8065 8066 8067 8068 8069 8070 8071 8072 8073 8074 8075 8076 8077 8078 8079 8080 8081 8082 8083 8084 8085 8086 8087 8088 8089 8090 8091 8092 8093 8094 8095 8096 8097 8098
				if (!filename) {
					ret = -ENOMEM;
					goto fail;
				}
			}

			state = IF_STATE_END;
			break;

		default:
			goto fail;
		}

		/*
		 * Filter definition is fully parsed, validate and install it.
		 * Make sure that it doesn't contradict itself or the event's
		 * attribute.
		 */
		if (state == IF_STATE_END) {
			if (kernel && event->attr.exclude_kernel)
				goto fail;

			if (!kernel) {
				if (!filename)
					goto fail;

				/* look up the path and grab its inode */
				ret = kern_path(filename, LOOKUP_FOLLOW, &path);
				if (ret)
					goto fail_free_name;

				filter->inode = igrab(d_inode(path.dentry));
				path_put(&path);
				kfree(filename);
				filename = NULL;

				ret = -EINVAL;
				if (!filter->inode ||
				    !S_ISREG(filter->inode->i_mode))
					/* free_filters_list() will iput() */
					goto fail;
			}

			/* ready to consume more filters */
			state = IF_STATE_ACTION;
			filter = NULL;
		}
	}

	if (state != IF_STATE_ACTION)
		goto fail;

	kfree(orig);

	return 0;

fail_free_name:
	kfree(filename);
fail:
	free_filters_list(filters);
	kfree(orig);

	return ret;
}

static int
perf_event_set_addr_filter(struct perf_event *event, char *filter_str)
{
	LIST_HEAD(filters);
	int ret;

	/*
	 * Since this is called in perf_ioctl() path, we're already holding
	 * ctx::mutex.
	 */
	lockdep_assert_held(&event->ctx->mutex);

	if (WARN_ON_ONCE(event->parent))
		return -EINVAL;

	/*
	 * For now, we only support filtering in per-task events; doing so
	 * for CPU-wide events requires additional context switching trickery,
	 * since same object code will be mapped at different virtual
	 * addresses in different processes.
	 */
	if (!event->ctx->task)
		return -EOPNOTSUPP;

	ret = perf_event_parse_addr_filter(event, filter_str, &filters);
	if (ret)
		return ret;

	ret = event->pmu->addr_filters_validate(&filters);
	if (ret) {
		free_filters_list(&filters);
		return ret;
	}

	/* remove existing filters, if any */
	perf_addr_filters_splice(event, &filters);

	/* install new filters */
	perf_event_for_each_child(event, perf_event_addr_filters_apply);

	return ret;
}

8099 8100 8101 8102 8103
static int perf_event_set_filter(struct perf_event *event, void __user *arg)
{
	char *filter_str;
	int ret = -EINVAL;

8104 8105 8106
	if ((event->attr.type != PERF_TYPE_TRACEPOINT ||
	    !IS_ENABLED(CONFIG_EVENT_TRACING)) &&
	    !has_addr_filter(event))
8107 8108 8109 8110 8111 8112 8113 8114 8115 8116
		return -EINVAL;

	filter_str = strndup_user(arg, PAGE_SIZE);
	if (IS_ERR(filter_str))
		return PTR_ERR(filter_str);

	if (IS_ENABLED(CONFIG_EVENT_TRACING) &&
	    event->attr.type == PERF_TYPE_TRACEPOINT)
		ret = ftrace_profile_set_filter(event, event->attr.config,
						filter_str);
8117 8118
	else if (has_addr_filter(event))
		ret = perf_event_set_addr_filter(event, filter_str);
8119 8120 8121 8122 8123

	kfree(filter_str);
	return ret;
}

8124 8125 8126
/*
 * hrtimer based swevent callback
 */
8127

8128
static enum hrtimer_restart perf_swevent_hrtimer(struct hrtimer *hrtimer)
8129
{
8130 8131 8132 8133 8134
	enum hrtimer_restart ret = HRTIMER_RESTART;
	struct perf_sample_data data;
	struct pt_regs *regs;
	struct perf_event *event;
	u64 period;
8135

8136
	event = container_of(hrtimer, struct perf_event, hw.hrtimer);
P
Peter Zijlstra 已提交
8137 8138 8139 8140

	if (event->state != PERF_EVENT_STATE_ACTIVE)
		return HRTIMER_NORESTART;

8141
	event->pmu->read(event);
8142

8143
	perf_sample_data_init(&data, 0, event->hw.last_period);
8144 8145 8146
	regs = get_irq_regs();

	if (regs && !perf_exclude_event(event, regs)) {
8147
		if (!(event->attr.exclude_idle && is_idle_task(current)))
8148
			if (__perf_event_overflow(event, 1, &data, regs))
8149 8150
				ret = HRTIMER_NORESTART;
	}
8151

8152 8153
	period = max_t(u64, 10000, event->hw.sample_period);
	hrtimer_forward_now(hrtimer, ns_to_ktime(period));
8154

8155
	return ret;
8156 8157
}

8158
static void perf_swevent_start_hrtimer(struct perf_event *event)
8159
{
8160
	struct hw_perf_event *hwc = &event->hw;
8161 8162 8163 8164
	s64 period;

	if (!is_sampling_event(event))
		return;
8165

8166 8167 8168 8169
	period = local64_read(&hwc->period_left);
	if (period) {
		if (period < 0)
			period = 10000;
P
Peter Zijlstra 已提交
8170

8171 8172 8173 8174
		local64_set(&hwc->period_left, 0);
	} else {
		period = max_t(u64, 10000, hwc->sample_period);
	}
8175 8176
	hrtimer_start(&hwc->hrtimer, ns_to_ktime(period),
		      HRTIMER_MODE_REL_PINNED);
8177
}
8178 8179

static void perf_swevent_cancel_hrtimer(struct perf_event *event)
8180
{
8181 8182
	struct hw_perf_event *hwc = &event->hw;

8183
	if (is_sampling_event(event)) {
8184
		ktime_t remaining = hrtimer_get_remaining(&hwc->hrtimer);
P
Peter Zijlstra 已提交
8185
		local64_set(&hwc->period_left, ktime_to_ns(remaining));
8186 8187 8188

		hrtimer_cancel(&hwc->hrtimer);
	}
8189 8190
}

P
Peter Zijlstra 已提交
8191 8192 8193 8194 8195 8196 8197 8198 8199 8200 8201 8202 8203 8204 8205 8206 8207 8208 8209 8210
static void perf_swevent_init_hrtimer(struct perf_event *event)
{
	struct hw_perf_event *hwc = &event->hw;

	if (!is_sampling_event(event))
		return;

	hrtimer_init(&hwc->hrtimer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
	hwc->hrtimer.function = perf_swevent_hrtimer;

	/*
	 * Since hrtimers have a fixed rate, we can do a static freq->period
	 * mapping and avoid the whole period adjust feedback stuff.
	 */
	if (event->attr.freq) {
		long freq = event->attr.sample_freq;

		event->attr.sample_period = NSEC_PER_SEC / freq;
		hwc->sample_period = event->attr.sample_period;
		local64_set(&hwc->period_left, hwc->sample_period);
8211
		hwc->last_period = hwc->sample_period;
P
Peter Zijlstra 已提交
8212 8213 8214 8215
		event->attr.freq = 0;
	}
}

8216 8217 8218 8219 8220
/*
 * Software event: cpu wall time clock
 */

static void cpu_clock_event_update(struct perf_event *event)
8221
{
8222 8223 8224
	s64 prev;
	u64 now;

P
Peter Zijlstra 已提交
8225
	now = local_clock();
8226 8227
	prev = local64_xchg(&event->hw.prev_count, now);
	local64_add(now - prev, &event->count);
8228 8229
}

P
Peter Zijlstra 已提交
8230
static void cpu_clock_event_start(struct perf_event *event, int flags)
8231
{
P
Peter Zijlstra 已提交
8232
	local64_set(&event->hw.prev_count, local_clock());
8233 8234 8235
	perf_swevent_start_hrtimer(event);
}

P
Peter Zijlstra 已提交
8236
static void cpu_clock_event_stop(struct perf_event *event, int flags)
8237
{
8238 8239 8240
	perf_swevent_cancel_hrtimer(event);
	cpu_clock_event_update(event);
}
8241

P
Peter Zijlstra 已提交
8242 8243 8244 8245
static int cpu_clock_event_add(struct perf_event *event, int flags)
{
	if (flags & PERF_EF_START)
		cpu_clock_event_start(event, flags);
8246
	perf_event_update_userpage(event);
P
Peter Zijlstra 已提交
8247 8248 8249 8250 8251 8252 8253 8254 8255

	return 0;
}

static void cpu_clock_event_del(struct perf_event *event, int flags)
{
	cpu_clock_event_stop(event, flags);
}

8256 8257 8258 8259
static void cpu_clock_event_read(struct perf_event *event)
{
	cpu_clock_event_update(event);
}
8260

8261 8262 8263 8264 8265 8266 8267 8268
static int cpu_clock_event_init(struct perf_event *event)
{
	if (event->attr.type != PERF_TYPE_SOFTWARE)
		return -ENOENT;

	if (event->attr.config != PERF_COUNT_SW_CPU_CLOCK)
		return -ENOENT;

8269 8270 8271 8272 8273 8274
	/*
	 * no branch sampling for software events
	 */
	if (has_branch_stack(event))
		return -EOPNOTSUPP;

P
Peter Zijlstra 已提交
8275 8276
	perf_swevent_init_hrtimer(event);

8277
	return 0;
8278 8279
}

8280
static struct pmu perf_cpu_clock = {
8281 8282
	.task_ctx_nr	= perf_sw_context,

8283 8284
	.capabilities	= PERF_PMU_CAP_NO_NMI,

8285
	.event_init	= cpu_clock_event_init,
P
Peter Zijlstra 已提交
8286 8287 8288 8289
	.add		= cpu_clock_event_add,
	.del		= cpu_clock_event_del,
	.start		= cpu_clock_event_start,
	.stop		= cpu_clock_event_stop,
8290 8291 8292 8293 8294 8295 8296 8297
	.read		= cpu_clock_event_read,
};

/*
 * Software event: task time clock
 */

static void task_clock_event_update(struct perf_event *event, u64 now)
8298
{
8299 8300
	u64 prev;
	s64 delta;
8301

8302 8303 8304 8305
	prev = local64_xchg(&event->hw.prev_count, now);
	delta = now - prev;
	local64_add(delta, &event->count);
}
8306

P
Peter Zijlstra 已提交
8307
static void task_clock_event_start(struct perf_event *event, int flags)
8308
{
P
Peter Zijlstra 已提交
8309
	local64_set(&event->hw.prev_count, event->ctx->time);
8310 8311 8312
	perf_swevent_start_hrtimer(event);
}

P
Peter Zijlstra 已提交
8313
static void task_clock_event_stop(struct perf_event *event, int flags)
8314 8315 8316
{
	perf_swevent_cancel_hrtimer(event);
	task_clock_event_update(event, event->ctx->time);
P
Peter Zijlstra 已提交
8317 8318 8319 8320 8321 8322
}

static int task_clock_event_add(struct perf_event *event, int flags)
{
	if (flags & PERF_EF_START)
		task_clock_event_start(event, flags);
8323
	perf_event_update_userpage(event);
8324

P
Peter Zijlstra 已提交
8325 8326 8327 8328 8329 8330
	return 0;
}

static void task_clock_event_del(struct perf_event *event, int flags)
{
	task_clock_event_stop(event, PERF_EF_UPDATE);
8331 8332 8333 8334
}

static void task_clock_event_read(struct perf_event *event)
{
8335 8336 8337
	u64 now = perf_clock();
	u64 delta = now - event->ctx->timestamp;
	u64 time = event->ctx->time + delta;
8338 8339 8340 8341 8342

	task_clock_event_update(event, time);
}

static int task_clock_event_init(struct perf_event *event)
L
Li Zefan 已提交
8343
{
8344 8345 8346 8347 8348 8349
	if (event->attr.type != PERF_TYPE_SOFTWARE)
		return -ENOENT;

	if (event->attr.config != PERF_COUNT_SW_TASK_CLOCK)
		return -ENOENT;

8350 8351 8352 8353 8354 8355
	/*
	 * no branch sampling for software events
	 */
	if (has_branch_stack(event))
		return -EOPNOTSUPP;

P
Peter Zijlstra 已提交
8356 8357
	perf_swevent_init_hrtimer(event);

8358
	return 0;
L
Li Zefan 已提交
8359 8360
}

8361
static struct pmu perf_task_clock = {
8362 8363
	.task_ctx_nr	= perf_sw_context,

8364 8365
	.capabilities	= PERF_PMU_CAP_NO_NMI,

8366
	.event_init	= task_clock_event_init,
P
Peter Zijlstra 已提交
8367 8368 8369 8370
	.add		= task_clock_event_add,
	.del		= task_clock_event_del,
	.start		= task_clock_event_start,
	.stop		= task_clock_event_stop,
8371 8372
	.read		= task_clock_event_read,
};
L
Li Zefan 已提交
8373

P
Peter Zijlstra 已提交
8374
static void perf_pmu_nop_void(struct pmu *pmu)
8375 8376
{
}
L
Li Zefan 已提交
8377

8378 8379 8380 8381
static void perf_pmu_nop_txn(struct pmu *pmu, unsigned int flags)
{
}

P
Peter Zijlstra 已提交
8382
static int perf_pmu_nop_int(struct pmu *pmu)
L
Li Zefan 已提交
8383
{
P
Peter Zijlstra 已提交
8384
	return 0;
L
Li Zefan 已提交
8385 8386
}

8387
static DEFINE_PER_CPU(unsigned int, nop_txn_flags);
8388 8389

static void perf_pmu_start_txn(struct pmu *pmu, unsigned int flags)
L
Li Zefan 已提交
8390
{
8391 8392 8393 8394 8395
	__this_cpu_write(nop_txn_flags, flags);

	if (flags & ~PERF_PMU_TXN_ADD)
		return;

P
Peter Zijlstra 已提交
8396
	perf_pmu_disable(pmu);
L
Li Zefan 已提交
8397 8398
}

P
Peter Zijlstra 已提交
8399 8400
static int perf_pmu_commit_txn(struct pmu *pmu)
{
8401 8402 8403 8404 8405 8406 8407
	unsigned int flags = __this_cpu_read(nop_txn_flags);

	__this_cpu_write(nop_txn_flags, 0);

	if (flags & ~PERF_PMU_TXN_ADD)
		return 0;

P
Peter Zijlstra 已提交
8408 8409 8410
	perf_pmu_enable(pmu);
	return 0;
}
8411

P
Peter Zijlstra 已提交
8412
static void perf_pmu_cancel_txn(struct pmu *pmu)
8413
{
8414 8415 8416 8417 8418 8419 8420
	unsigned int flags =  __this_cpu_read(nop_txn_flags);

	__this_cpu_write(nop_txn_flags, 0);

	if (flags & ~PERF_PMU_TXN_ADD)
		return;

P
Peter Zijlstra 已提交
8421
	perf_pmu_enable(pmu);
8422 8423
}

8424 8425
static int perf_event_idx_default(struct perf_event *event)
{
8426
	return 0;
8427 8428
}

P
Peter Zijlstra 已提交
8429 8430 8431 8432
/*
 * Ensures all contexts with the same task_ctx_nr have the same
 * pmu_cpu_context too.
 */
8433
static struct perf_cpu_context __percpu *find_pmu_context(int ctxn)
8434
{
P
Peter Zijlstra 已提交
8435
	struct pmu *pmu;
8436

P
Peter Zijlstra 已提交
8437 8438
	if (ctxn < 0)
		return NULL;
8439

P
Peter Zijlstra 已提交
8440 8441 8442 8443
	list_for_each_entry(pmu, &pmus, entry) {
		if (pmu->task_ctx_nr == ctxn)
			return pmu->pmu_cpu_context;
	}
8444

P
Peter Zijlstra 已提交
8445
	return NULL;
8446 8447
}

8448
static void update_pmu_context(struct pmu *pmu, struct pmu *old_pmu)
8449
{
8450 8451 8452 8453 8454 8455 8456
	int cpu;

	for_each_possible_cpu(cpu) {
		struct perf_cpu_context *cpuctx;

		cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);

8457 8458
		if (cpuctx->unique_pmu == old_pmu)
			cpuctx->unique_pmu = pmu;
8459 8460 8461 8462 8463 8464
	}
}

static void free_pmu_context(struct pmu *pmu)
{
	struct pmu *i;
8465

P
Peter Zijlstra 已提交
8466
	mutex_lock(&pmus_lock);
8467
	/*
P
Peter Zijlstra 已提交
8468
	 * Like a real lame refcount.
8469
	 */
8470 8471 8472
	list_for_each_entry(i, &pmus, entry) {
		if (i->pmu_cpu_context == pmu->pmu_cpu_context) {
			update_pmu_context(i, pmu);
P
Peter Zijlstra 已提交
8473
			goto out;
8474
		}
P
Peter Zijlstra 已提交
8475
	}
8476

8477
	free_percpu(pmu->pmu_cpu_context);
P
Peter Zijlstra 已提交
8478 8479
out:
	mutex_unlock(&pmus_lock);
8480
}
8481 8482 8483 8484 8485 8486 8487 8488 8489 8490 8491 8492 8493 8494

/*
 * Let userspace know that this PMU supports address range filtering:
 */
static ssize_t nr_addr_filters_show(struct device *dev,
				    struct device_attribute *attr,
				    char *page)
{
	struct pmu *pmu = dev_get_drvdata(dev);

	return snprintf(page, PAGE_SIZE - 1, "%d\n", pmu->nr_addr_filters);
}
DEVICE_ATTR_RO(nr_addr_filters);

P
Peter Zijlstra 已提交
8495
static struct idr pmu_idr;
8496

P
Peter Zijlstra 已提交
8497 8498 8499 8500 8501 8502 8503
static ssize_t
type_show(struct device *dev, struct device_attribute *attr, char *page)
{
	struct pmu *pmu = dev_get_drvdata(dev);

	return snprintf(page, PAGE_SIZE-1, "%d\n", pmu->type);
}
8504
static DEVICE_ATTR_RO(type);
P
Peter Zijlstra 已提交
8505

8506 8507 8508 8509 8510 8511 8512 8513 8514 8515
static ssize_t
perf_event_mux_interval_ms_show(struct device *dev,
				struct device_attribute *attr,
				char *page)
{
	struct pmu *pmu = dev_get_drvdata(dev);

	return snprintf(page, PAGE_SIZE-1, "%d\n", pmu->hrtimer_interval_ms);
}

8516 8517
static DEFINE_MUTEX(mux_interval_mutex);

8518 8519 8520 8521 8522 8523 8524 8525 8526 8527 8528 8529 8530 8531 8532 8533 8534 8535 8536
static ssize_t
perf_event_mux_interval_ms_store(struct device *dev,
				 struct device_attribute *attr,
				 const char *buf, size_t count)
{
	struct pmu *pmu = dev_get_drvdata(dev);
	int timer, cpu, ret;

	ret = kstrtoint(buf, 0, &timer);
	if (ret)
		return ret;

	if (timer < 1)
		return -EINVAL;

	/* same value, noting to do */
	if (timer == pmu->hrtimer_interval_ms)
		return count;

8537
	mutex_lock(&mux_interval_mutex);
8538 8539 8540
	pmu->hrtimer_interval_ms = timer;

	/* update all cpuctx for this PMU */
8541 8542
	get_online_cpus();
	for_each_online_cpu(cpu) {
8543 8544 8545 8546
		struct perf_cpu_context *cpuctx;
		cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
		cpuctx->hrtimer_interval = ns_to_ktime(NSEC_PER_MSEC * timer);

8547 8548
		cpu_function_call(cpu,
			(remote_function_f)perf_mux_hrtimer_restart, cpuctx);
8549
	}
8550 8551
	put_online_cpus();
	mutex_unlock(&mux_interval_mutex);
8552 8553 8554

	return count;
}
8555
static DEVICE_ATTR_RW(perf_event_mux_interval_ms);
8556

8557 8558 8559 8560
static struct attribute *pmu_dev_attrs[] = {
	&dev_attr_type.attr,
	&dev_attr_perf_event_mux_interval_ms.attr,
	NULL,
P
Peter Zijlstra 已提交
8561
};
8562
ATTRIBUTE_GROUPS(pmu_dev);
P
Peter Zijlstra 已提交
8563 8564 8565 8566

static int pmu_bus_running;
static struct bus_type pmu_bus = {
	.name		= "event_source",
8567
	.dev_groups	= pmu_dev_groups,
P
Peter Zijlstra 已提交
8568 8569 8570 8571 8572 8573 8574 8575 8576 8577 8578 8579 8580 8581 8582
};

static void pmu_dev_release(struct device *dev)
{
	kfree(dev);
}

static int pmu_dev_alloc(struct pmu *pmu)
{
	int ret = -ENOMEM;

	pmu->dev = kzalloc(sizeof(struct device), GFP_KERNEL);
	if (!pmu->dev)
		goto out;

8583
	pmu->dev->groups = pmu->attr_groups;
P
Peter Zijlstra 已提交
8584 8585 8586 8587 8588 8589 8590 8591 8592 8593 8594 8595
	device_initialize(pmu->dev);
	ret = dev_set_name(pmu->dev, "%s", pmu->name);
	if (ret)
		goto free_dev;

	dev_set_drvdata(pmu->dev, pmu);
	pmu->dev->bus = &pmu_bus;
	pmu->dev->release = pmu_dev_release;
	ret = device_add(pmu->dev);
	if (ret)
		goto free_dev;

8596 8597 8598 8599 8600 8601 8602
	/* For PMUs with address filters, throw in an extra attribute: */
	if (pmu->nr_addr_filters)
		ret = device_create_file(pmu->dev, &dev_attr_nr_addr_filters);

	if (ret)
		goto del_dev;

P
Peter Zijlstra 已提交
8603 8604 8605
out:
	return ret;

8606 8607 8608
del_dev:
	device_del(pmu->dev);

P
Peter Zijlstra 已提交
8609 8610 8611 8612 8613
free_dev:
	put_device(pmu->dev);
	goto out;
}

8614
static struct lock_class_key cpuctx_mutex;
8615
static struct lock_class_key cpuctx_lock;
8616

8617
int perf_pmu_register(struct pmu *pmu, const char *name, int type)
8618
{
P
Peter Zijlstra 已提交
8619
	int cpu, ret;
8620

8621
	mutex_lock(&pmus_lock);
P
Peter Zijlstra 已提交
8622 8623 8624 8625
	ret = -ENOMEM;
	pmu->pmu_disable_count = alloc_percpu(int);
	if (!pmu->pmu_disable_count)
		goto unlock;
8626

P
Peter Zijlstra 已提交
8627 8628 8629 8630 8631 8632
	pmu->type = -1;
	if (!name)
		goto skip_type;
	pmu->name = name;

	if (type < 0) {
T
Tejun Heo 已提交
8633 8634 8635
		type = idr_alloc(&pmu_idr, pmu, PERF_TYPE_MAX, 0, GFP_KERNEL);
		if (type < 0) {
			ret = type;
P
Peter Zijlstra 已提交
8636 8637 8638 8639 8640
			goto free_pdc;
		}
	}
	pmu->type = type;

P
Peter Zijlstra 已提交
8641 8642 8643 8644 8645 8646
	if (pmu_bus_running) {
		ret = pmu_dev_alloc(pmu);
		if (ret)
			goto free_idr;
	}

P
Peter Zijlstra 已提交
8647
skip_type:
8648 8649 8650
	if (pmu->task_ctx_nr == perf_hw_context) {
		static int hw_context_taken = 0;

8651 8652 8653 8654 8655 8656 8657
		/*
		 * Other than systems with heterogeneous CPUs, it never makes
		 * sense for two PMUs to share perf_hw_context. PMUs which are
		 * uncore must use perf_invalid_context.
		 */
		if (WARN_ON_ONCE(hw_context_taken &&
		    !(pmu->capabilities & PERF_PMU_CAP_HETEROGENEOUS_CPUS)))
8658 8659 8660 8661 8662
			pmu->task_ctx_nr = perf_invalid_context;

		hw_context_taken = 1;
	}

P
Peter Zijlstra 已提交
8663 8664 8665
	pmu->pmu_cpu_context = find_pmu_context(pmu->task_ctx_nr);
	if (pmu->pmu_cpu_context)
		goto got_cpu_context;
8666

W
Wei Yongjun 已提交
8667
	ret = -ENOMEM;
P
Peter Zijlstra 已提交
8668 8669
	pmu->pmu_cpu_context = alloc_percpu(struct perf_cpu_context);
	if (!pmu->pmu_cpu_context)
P
Peter Zijlstra 已提交
8670
		goto free_dev;
8671

P
Peter Zijlstra 已提交
8672 8673 8674 8675
	for_each_possible_cpu(cpu) {
		struct perf_cpu_context *cpuctx;

		cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
8676
		__perf_event_init_context(&cpuctx->ctx);
8677
		lockdep_set_class(&cpuctx->ctx.mutex, &cpuctx_mutex);
8678
		lockdep_set_class(&cpuctx->ctx.lock, &cpuctx_lock);
P
Peter Zijlstra 已提交
8679
		cpuctx->ctx.pmu = pmu;
8680

8681
		__perf_mux_hrtimer_init(cpuctx, cpu);
8682

8683
		cpuctx->unique_pmu = pmu;
P
Peter Zijlstra 已提交
8684
	}
8685

P
Peter Zijlstra 已提交
8686
got_cpu_context:
P
Peter Zijlstra 已提交
8687 8688 8689 8690 8691 8692 8693 8694 8695 8696 8697
	if (!pmu->start_txn) {
		if (pmu->pmu_enable) {
			/*
			 * If we have pmu_enable/pmu_disable calls, install
			 * transaction stubs that use that to try and batch
			 * hardware accesses.
			 */
			pmu->start_txn  = perf_pmu_start_txn;
			pmu->commit_txn = perf_pmu_commit_txn;
			pmu->cancel_txn = perf_pmu_cancel_txn;
		} else {
8698
			pmu->start_txn  = perf_pmu_nop_txn;
P
Peter Zijlstra 已提交
8699 8700
			pmu->commit_txn = perf_pmu_nop_int;
			pmu->cancel_txn = perf_pmu_nop_void;
8701
		}
8702
	}
8703

P
Peter Zijlstra 已提交
8704 8705 8706 8707 8708
	if (!pmu->pmu_enable) {
		pmu->pmu_enable  = perf_pmu_nop_void;
		pmu->pmu_disable = perf_pmu_nop_void;
	}

8709 8710 8711
	if (!pmu->event_idx)
		pmu->event_idx = perf_event_idx_default;

8712
	list_add_rcu(&pmu->entry, &pmus);
8713
	atomic_set(&pmu->exclusive_cnt, 0);
P
Peter Zijlstra 已提交
8714 8715
	ret = 0;
unlock:
8716 8717
	mutex_unlock(&pmus_lock);

P
Peter Zijlstra 已提交
8718
	return ret;
P
Peter Zijlstra 已提交
8719

P
Peter Zijlstra 已提交
8720 8721 8722 8723
free_dev:
	device_del(pmu->dev);
	put_device(pmu->dev);

P
Peter Zijlstra 已提交
8724 8725 8726 8727
free_idr:
	if (pmu->type >= PERF_TYPE_MAX)
		idr_remove(&pmu_idr, pmu->type);

P
Peter Zijlstra 已提交
8728 8729 8730
free_pdc:
	free_percpu(pmu->pmu_disable_count);
	goto unlock;
8731
}
8732
EXPORT_SYMBOL_GPL(perf_pmu_register);
8733

8734
void perf_pmu_unregister(struct pmu *pmu)
8735
{
8736 8737 8738
	mutex_lock(&pmus_lock);
	list_del_rcu(&pmu->entry);
	mutex_unlock(&pmus_lock);
8739

8740
	/*
P
Peter Zijlstra 已提交
8741 8742
	 * We dereference the pmu list under both SRCU and regular RCU, so
	 * synchronize against both of those.
8743
	 */
8744
	synchronize_srcu(&pmus_srcu);
P
Peter Zijlstra 已提交
8745
	synchronize_rcu();
8746

P
Peter Zijlstra 已提交
8747
	free_percpu(pmu->pmu_disable_count);
P
Peter Zijlstra 已提交
8748 8749
	if (pmu->type >= PERF_TYPE_MAX)
		idr_remove(&pmu_idr, pmu->type);
8750 8751
	if (pmu->nr_addr_filters)
		device_remove_file(pmu->dev, &dev_attr_nr_addr_filters);
P
Peter Zijlstra 已提交
8752 8753
	device_del(pmu->dev);
	put_device(pmu->dev);
8754
	free_pmu_context(pmu);
8755
}
8756
EXPORT_SYMBOL_GPL(perf_pmu_unregister);
8757

8758 8759
static int perf_try_init_event(struct pmu *pmu, struct perf_event *event)
{
P
Peter Zijlstra 已提交
8760
	struct perf_event_context *ctx = NULL;
8761 8762 8763 8764
	int ret;

	if (!try_module_get(pmu->module))
		return -ENODEV;
P
Peter Zijlstra 已提交
8765 8766

	if (event->group_leader != event) {
8767 8768 8769 8770 8771 8772
		/*
		 * This ctx->mutex can nest when we're called through
		 * inheritance. See the perf_event_ctx_lock_nested() comment.
		 */
		ctx = perf_event_ctx_lock_nested(event->group_leader,
						 SINGLE_DEPTH_NESTING);
P
Peter Zijlstra 已提交
8773 8774 8775
		BUG_ON(!ctx);
	}

8776 8777
	event->pmu = pmu;
	ret = pmu->event_init(event);
P
Peter Zijlstra 已提交
8778 8779 8780 8781

	if (ctx)
		perf_event_ctx_unlock(event->group_leader, ctx);

8782 8783 8784 8785 8786 8787
	if (ret)
		module_put(pmu->module);

	return ret;
}

8788
static struct pmu *perf_init_event(struct perf_event *event)
8789 8790 8791
{
	struct pmu *pmu = NULL;
	int idx;
8792
	int ret;
8793 8794

	idx = srcu_read_lock(&pmus_srcu);
P
Peter Zijlstra 已提交
8795 8796 8797 8798

	rcu_read_lock();
	pmu = idr_find(&pmu_idr, event->attr.type);
	rcu_read_unlock();
8799
	if (pmu) {
8800
		ret = perf_try_init_event(pmu, event);
8801 8802
		if (ret)
			pmu = ERR_PTR(ret);
P
Peter Zijlstra 已提交
8803
		goto unlock;
8804
	}
P
Peter Zijlstra 已提交
8805

8806
	list_for_each_entry_rcu(pmu, &pmus, entry) {
8807
		ret = perf_try_init_event(pmu, event);
8808
		if (!ret)
P
Peter Zijlstra 已提交
8809
			goto unlock;
8810

8811 8812
		if (ret != -ENOENT) {
			pmu = ERR_PTR(ret);
P
Peter Zijlstra 已提交
8813
			goto unlock;
8814
		}
8815
	}
P
Peter Zijlstra 已提交
8816 8817
	pmu = ERR_PTR(-ENOENT);
unlock:
8818
	srcu_read_unlock(&pmus_srcu, idx);
8819

8820
	return pmu;
8821 8822
}

8823 8824 8825 8826 8827 8828 8829 8830 8831
static void attach_sb_event(struct perf_event *event)
{
	struct pmu_event_list *pel = per_cpu_ptr(&pmu_sb_events, event->cpu);

	raw_spin_lock(&pel->lock);
	list_add_rcu(&event->sb_list, &pel->list);
	raw_spin_unlock(&pel->lock);
}

8832 8833 8834 8835 8836 8837 8838
/*
 * We keep a list of all !task (and therefore per-cpu) events
 * that need to receive side-band records.
 *
 * This avoids having to scan all the various PMU per-cpu contexts
 * looking for them.
 */
8839 8840
static void account_pmu_sb_event(struct perf_event *event)
{
8841
	if (is_sb_event(event))
8842 8843 8844
		attach_sb_event(event);
}

8845 8846 8847 8848 8849 8850 8851 8852 8853
static void account_event_cpu(struct perf_event *event, int cpu)
{
	if (event->parent)
		return;

	if (is_cgroup_event(event))
		atomic_inc(&per_cpu(perf_cgroup_events, cpu));
}

8854 8855 8856 8857 8858 8859 8860 8861 8862 8863 8864 8865 8866 8867 8868 8869 8870 8871 8872 8873 8874
/* Freq events need the tick to stay alive (see perf_event_task_tick). */
static void account_freq_event_nohz(void)
{
#ifdef CONFIG_NO_HZ_FULL
	/* Lock so we don't race with concurrent unaccount */
	spin_lock(&nr_freq_lock);
	if (atomic_inc_return(&nr_freq_events) == 1)
		tick_nohz_dep_set(TICK_DEP_BIT_PERF_EVENTS);
	spin_unlock(&nr_freq_lock);
#endif
}

static void account_freq_event(void)
{
	if (tick_nohz_full_enabled())
		account_freq_event_nohz();
	else
		atomic_inc(&nr_freq_events);
}


8875 8876
static void account_event(struct perf_event *event)
{
8877 8878
	bool inc = false;

8879 8880 8881
	if (event->parent)
		return;

8882
	if (event->attach_state & PERF_ATTACH_TASK)
8883
		inc = true;
8884 8885 8886 8887 8888 8889
	if (event->attr.mmap || event->attr.mmap_data)
		atomic_inc(&nr_mmap_events);
	if (event->attr.comm)
		atomic_inc(&nr_comm_events);
	if (event->attr.task)
		atomic_inc(&nr_task_events);
8890 8891
	if (event->attr.freq)
		account_freq_event();
8892 8893
	if (event->attr.context_switch) {
		atomic_inc(&nr_switch_events);
8894
		inc = true;
8895
	}
8896
	if (has_branch_stack(event))
8897
		inc = true;
8898
	if (is_cgroup_event(event))
8899 8900
		inc = true;

8901 8902 8903 8904 8905 8906 8907 8908 8909 8910 8911 8912 8913 8914 8915 8916 8917 8918 8919 8920 8921 8922
	if (inc) {
		if (atomic_inc_not_zero(&perf_sched_count))
			goto enabled;

		mutex_lock(&perf_sched_mutex);
		if (!atomic_read(&perf_sched_count)) {
			static_branch_enable(&perf_sched_events);
			/*
			 * Guarantee that all CPUs observe they key change and
			 * call the perf scheduling hooks before proceeding to
			 * install events that need them.
			 */
			synchronize_sched();
		}
		/*
		 * Now that we have waited for the sync_sched(), allow further
		 * increments to by-pass the mutex.
		 */
		atomic_inc(&perf_sched_count);
		mutex_unlock(&perf_sched_mutex);
	}
enabled:
8923 8924

	account_event_cpu(event, event->cpu);
8925 8926

	account_pmu_sb_event(event);
8927 8928
}

T
Thomas Gleixner 已提交
8929
/*
8930
 * Allocate and initialize a event structure
T
Thomas Gleixner 已提交
8931
 */
8932
static struct perf_event *
8933
perf_event_alloc(struct perf_event_attr *attr, int cpu,
8934 8935 8936
		 struct task_struct *task,
		 struct perf_event *group_leader,
		 struct perf_event *parent_event,
8937
		 perf_overflow_handler_t overflow_handler,
8938
		 void *context, int cgroup_fd)
T
Thomas Gleixner 已提交
8939
{
P
Peter Zijlstra 已提交
8940
	struct pmu *pmu;
8941 8942
	struct perf_event *event;
	struct hw_perf_event *hwc;
8943
	long err = -EINVAL;
T
Thomas Gleixner 已提交
8944

8945 8946 8947 8948 8949
	if ((unsigned)cpu >= nr_cpu_ids) {
		if (!task || cpu != -1)
			return ERR_PTR(-EINVAL);
	}

8950
	event = kzalloc(sizeof(*event), GFP_KERNEL);
8951
	if (!event)
8952
		return ERR_PTR(-ENOMEM);
T
Thomas Gleixner 已提交
8953

8954
	/*
8955
	 * Single events are their own group leaders, with an
8956 8957 8958
	 * empty sibling list:
	 */
	if (!group_leader)
8959
		group_leader = event;
8960

8961 8962
	mutex_init(&event->child_mutex);
	INIT_LIST_HEAD(&event->child_list);
8963

8964 8965 8966
	INIT_LIST_HEAD(&event->group_entry);
	INIT_LIST_HEAD(&event->event_entry);
	INIT_LIST_HEAD(&event->sibling_list);
8967
	INIT_LIST_HEAD(&event->rb_entry);
8968
	INIT_LIST_HEAD(&event->active_entry);
8969
	INIT_LIST_HEAD(&event->addr_filters.list);
8970 8971
	INIT_HLIST_NODE(&event->hlist_entry);

8972

8973
	init_waitqueue_head(&event->waitq);
8974
	init_irq_work(&event->pending, perf_pending_event);
T
Thomas Gleixner 已提交
8975

8976
	mutex_init(&event->mmap_mutex);
8977
	raw_spin_lock_init(&event->addr_filters.lock);
8978

8979
	atomic_long_set(&event->refcount, 1);
8980 8981 8982 8983 8984
	event->cpu		= cpu;
	event->attr		= *attr;
	event->group_leader	= group_leader;
	event->pmu		= NULL;
	event->oncpu		= -1;
8985

8986
	event->parent		= parent_event;
8987

8988
	event->ns		= get_pid_ns(task_active_pid_ns(current));
8989
	event->id		= atomic64_inc_return(&perf_event_id);
8990

8991
	event->state		= PERF_EVENT_STATE_INACTIVE;
8992

8993 8994 8995
	if (task) {
		event->attach_state = PERF_ATTACH_TASK;
		/*
8996 8997 8998
		 * XXX pmu::event_init needs to know what task to account to
		 * and we cannot use the ctx information because we need the
		 * pmu before we get a ctx.
8999
		 */
9000
		event->hw.target = task;
9001 9002
	}

9003 9004 9005 9006
	event->clock = &local_clock;
	if (parent_event)
		event->clock = parent_event->clock;

9007
	if (!overflow_handler && parent_event) {
9008
		overflow_handler = parent_event->overflow_handler;
9009 9010
		context = parent_event->overflow_handler_context;
	}
9011

9012 9013 9014
	if (overflow_handler) {
		event->overflow_handler	= overflow_handler;
		event->overflow_handler_context = context;
9015 9016 9017
	} else if (is_write_backward(event)){
		event->overflow_handler = perf_event_output_backward;
		event->overflow_handler_context = NULL;
9018
	} else {
9019
		event->overflow_handler = perf_event_output_forward;
9020 9021
		event->overflow_handler_context = NULL;
	}
9022

J
Jiri Olsa 已提交
9023
	perf_event__state_init(event);
9024

9025
	pmu = NULL;
9026

9027
	hwc = &event->hw;
9028
	hwc->sample_period = attr->sample_period;
9029
	if (attr->freq && attr->sample_freq)
9030
		hwc->sample_period = 1;
9031
	hwc->last_period = hwc->sample_period;
9032

9033
	local64_set(&hwc->period_left, hwc->sample_period);
9034

9035
	/*
9036
	 * we currently do not support PERF_FORMAT_GROUP on inherited events
9037
	 */
9038
	if (attr->inherit && (attr->read_format & PERF_FORMAT_GROUP))
9039
		goto err_ns;
9040 9041 9042

	if (!has_branch_stack(event))
		event->attr.branch_sample_type = 0;
9043

9044 9045 9046 9047 9048 9049
	if (cgroup_fd != -1) {
		err = perf_cgroup_connect(cgroup_fd, event, attr, group_leader);
		if (err)
			goto err_ns;
	}

9050
	pmu = perf_init_event(event);
9051
	if (!pmu)
9052 9053
		goto err_ns;
	else if (IS_ERR(pmu)) {
9054
		err = PTR_ERR(pmu);
9055
		goto err_ns;
I
Ingo Molnar 已提交
9056
	}
9057

9058 9059 9060 9061
	err = exclusive_event_init(event);
	if (err)
		goto err_pmu;

9062 9063 9064 9065 9066 9067 9068 9069 9070 9071 9072
	if (has_addr_filter(event)) {
		event->addr_filters_offs = kcalloc(pmu->nr_addr_filters,
						   sizeof(unsigned long),
						   GFP_KERNEL);
		if (!event->addr_filters_offs)
			goto err_per_task;

		/* force hw sync on the address filters */
		event->addr_filters_gen = 1;
	}

9073
	if (!event->parent) {
9074
		if (event->attr.sample_type & PERF_SAMPLE_CALLCHAIN) {
9075
			err = get_callchain_buffers(attr->sample_max_stack);
9076
			if (err)
9077
				goto err_addr_filters;
9078
		}
9079
	}
9080

9081 9082 9083
	/* symmetric to unaccount_event() in _free_event() */
	account_event(event);

9084
	return event;
9085

9086 9087 9088
err_addr_filters:
	kfree(event->addr_filters_offs);

9089 9090 9091
err_per_task:
	exclusive_event_destroy(event);

9092 9093 9094
err_pmu:
	if (event->destroy)
		event->destroy(event);
9095
	module_put(pmu->module);
9096
err_ns:
9097 9098
	if (is_cgroup_event(event))
		perf_detach_cgroup(event);
9099 9100 9101 9102 9103
	if (event->ns)
		put_pid_ns(event->ns);
	kfree(event);

	return ERR_PTR(err);
T
Thomas Gleixner 已提交
9104 9105
}

9106 9107
static int perf_copy_attr(struct perf_event_attr __user *uattr,
			  struct perf_event_attr *attr)
9108 9109
{
	u32 size;
9110
	int ret;
9111 9112 9113 9114 9115 9116 9117 9118 9119 9120 9121 9122 9123 9124 9125 9126 9127 9128 9129 9130 9131 9132 9133 9134

	if (!access_ok(VERIFY_WRITE, uattr, PERF_ATTR_SIZE_VER0))
		return -EFAULT;

	/*
	 * zero the full structure, so that a short copy will be nice.
	 */
	memset(attr, 0, sizeof(*attr));

	ret = get_user(size, &uattr->size);
	if (ret)
		return ret;

	if (size > PAGE_SIZE)	/* silly large */
		goto err_size;

	if (!size)		/* abi compat */
		size = PERF_ATTR_SIZE_VER0;

	if (size < PERF_ATTR_SIZE_VER0)
		goto err_size;

	/*
	 * If we're handed a bigger struct than we know of,
9135 9136 9137
	 * ensure all the unknown bits are 0 - i.e. new
	 * user-space does not rely on any kernel feature
	 * extensions we dont know about yet.
9138 9139
	 */
	if (size > sizeof(*attr)) {
9140 9141 9142
		unsigned char __user *addr;
		unsigned char __user *end;
		unsigned char val;
9143

9144 9145
		addr = (void __user *)uattr + sizeof(*attr);
		end  = (void __user *)uattr + size;
9146

9147
		for (; addr < end; addr++) {
9148 9149 9150 9151 9152 9153
			ret = get_user(val, addr);
			if (ret)
				return ret;
			if (val)
				goto err_size;
		}
9154
		size = sizeof(*attr);
9155 9156 9157 9158 9159 9160
	}

	ret = copy_from_user(attr, uattr, size);
	if (ret)
		return -EFAULT;

9161
	if (attr->__reserved_1)
9162 9163 9164 9165 9166 9167 9168 9169
		return -EINVAL;

	if (attr->sample_type & ~(PERF_SAMPLE_MAX-1))
		return -EINVAL;

	if (attr->read_format & ~(PERF_FORMAT_MAX-1))
		return -EINVAL;

9170 9171 9172 9173 9174 9175 9176 9177 9178 9179 9180 9181 9182 9183 9184 9185 9186 9187 9188 9189 9190 9191 9192 9193 9194 9195 9196 9197
	if (attr->sample_type & PERF_SAMPLE_BRANCH_STACK) {
		u64 mask = attr->branch_sample_type;

		/* only using defined bits */
		if (mask & ~(PERF_SAMPLE_BRANCH_MAX-1))
			return -EINVAL;

		/* at least one branch bit must be set */
		if (!(mask & ~PERF_SAMPLE_BRANCH_PLM_ALL))
			return -EINVAL;

		/* propagate priv level, when not set for branch */
		if (!(mask & PERF_SAMPLE_BRANCH_PLM_ALL)) {

			/* exclude_kernel checked on syscall entry */
			if (!attr->exclude_kernel)
				mask |= PERF_SAMPLE_BRANCH_KERNEL;

			if (!attr->exclude_user)
				mask |= PERF_SAMPLE_BRANCH_USER;

			if (!attr->exclude_hv)
				mask |= PERF_SAMPLE_BRANCH_HV;
			/*
			 * adjust user setting (for HW filter setup)
			 */
			attr->branch_sample_type = mask;
		}
9198 9199
		/* privileged levels capture (kernel, hv): check permissions */
		if ((mask & PERF_SAMPLE_BRANCH_PERM_PLM)
9200 9201
		    && perf_paranoid_kernel() && !capable(CAP_SYS_ADMIN))
			return -EACCES;
9202
	}
9203

9204
	if (attr->sample_type & PERF_SAMPLE_REGS_USER) {
9205
		ret = perf_reg_validate(attr->sample_regs_user);
9206 9207 9208 9209 9210 9211 9212 9213 9214 9215 9216 9217 9218 9219 9220 9221 9222 9223
		if (ret)
			return ret;
	}

	if (attr->sample_type & PERF_SAMPLE_STACK_USER) {
		if (!arch_perf_have_user_stack_dump())
			return -ENOSYS;

		/*
		 * We have __u32 type for the size, but so far
		 * we can only use __u16 as maximum due to the
		 * __u16 sample size limit.
		 */
		if (attr->sample_stack_user >= USHRT_MAX)
			ret = -EINVAL;
		else if (!IS_ALIGNED(attr->sample_stack_user, sizeof(u64)))
			ret = -EINVAL;
	}
9224

9225 9226
	if (attr->sample_type & PERF_SAMPLE_REGS_INTR)
		ret = perf_reg_validate(attr->sample_regs_intr);
9227 9228 9229 9230 9231 9232 9233 9234 9235
out:
	return ret;

err_size:
	put_user(sizeof(*attr), &uattr->size);
	ret = -E2BIG;
	goto out;
}

9236 9237
static int
perf_event_set_output(struct perf_event *event, struct perf_event *output_event)
9238
{
9239
	struct ring_buffer *rb = NULL;
9240 9241
	int ret = -EINVAL;

9242
	if (!output_event)
9243 9244
		goto set;

9245 9246
	/* don't allow circular references */
	if (event == output_event)
9247 9248
		goto out;

9249 9250 9251 9252 9253 9254 9255
	/*
	 * Don't allow cross-cpu buffers
	 */
	if (output_event->cpu != event->cpu)
		goto out;

	/*
9256
	 * If its not a per-cpu rb, it must be the same task.
9257 9258 9259 9260
	 */
	if (output_event->cpu == -1 && output_event->ctx != event->ctx)
		goto out;

9261 9262 9263 9264 9265 9266
	/*
	 * Mixing clocks in the same buffer is trouble you don't need.
	 */
	if (output_event->clock != event->clock)
		goto out;

9267 9268 9269 9270 9271 9272 9273
	/*
	 * Either writing ring buffer from beginning or from end.
	 * Mixing is not allowed.
	 */
	if (is_write_backward(output_event) != is_write_backward(event))
		goto out;

9274 9275 9276 9277 9278 9279 9280
	/*
	 * If both events generate aux data, they must be on the same PMU
	 */
	if (has_aux(event) && has_aux(output_event) &&
	    event->pmu != output_event->pmu)
		goto out;

9281
set:
9282
	mutex_lock(&event->mmap_mutex);
9283 9284 9285
	/* Can't redirect output if we've got an active mmap() */
	if (atomic_read(&event->mmap_count))
		goto unlock;
9286

9287
	if (output_event) {
9288 9289 9290
		/* get the rb we want to redirect to */
		rb = ring_buffer_get(output_event);
		if (!rb)
9291
			goto unlock;
9292 9293
	}

9294
	ring_buffer_attach(event, rb);
9295

9296
	ret = 0;
9297 9298 9299
unlock:
	mutex_unlock(&event->mmap_mutex);

9300 9301 9302 9303
out:
	return ret;
}

P
Peter Zijlstra 已提交
9304 9305 9306 9307 9308 9309 9310 9311 9312
static void mutex_lock_double(struct mutex *a, struct mutex *b)
{
	if (b < a)
		swap(a, b);

	mutex_lock(a);
	mutex_lock_nested(b, SINGLE_DEPTH_NESTING);
}

9313 9314 9315 9316 9317 9318 9319 9320 9321 9322 9323 9324 9325 9326 9327 9328 9329 9330 9331 9332 9333 9334 9335 9336 9337 9338 9339 9340 9341 9342 9343 9344 9345 9346 9347 9348 9349
static int perf_event_set_clock(struct perf_event *event, clockid_t clk_id)
{
	bool nmi_safe = false;

	switch (clk_id) {
	case CLOCK_MONOTONIC:
		event->clock = &ktime_get_mono_fast_ns;
		nmi_safe = true;
		break;

	case CLOCK_MONOTONIC_RAW:
		event->clock = &ktime_get_raw_fast_ns;
		nmi_safe = true;
		break;

	case CLOCK_REALTIME:
		event->clock = &ktime_get_real_ns;
		break;

	case CLOCK_BOOTTIME:
		event->clock = &ktime_get_boot_ns;
		break;

	case CLOCK_TAI:
		event->clock = &ktime_get_tai_ns;
		break;

	default:
		return -EINVAL;
	}

	if (!nmi_safe && !(event->pmu->capabilities & PERF_PMU_CAP_NO_NMI))
		return -EINVAL;

	return 0;
}

T
Thomas Gleixner 已提交
9350
/**
9351
 * sys_perf_event_open - open a performance event, associate it to a task/cpu
I
Ingo Molnar 已提交
9352
 *
9353
 * @attr_uptr:	event_id type attributes for monitoring/sampling
T
Thomas Gleixner 已提交
9354
 * @pid:		target pid
I
Ingo Molnar 已提交
9355
 * @cpu:		target cpu
9356
 * @group_fd:		group leader event fd
T
Thomas Gleixner 已提交
9357
 */
9358 9359
SYSCALL_DEFINE5(perf_event_open,
		struct perf_event_attr __user *, attr_uptr,
9360
		pid_t, pid, int, cpu, int, group_fd, unsigned long, flags)
T
Thomas Gleixner 已提交
9361
{
9362 9363
	struct perf_event *group_leader = NULL, *output_event = NULL;
	struct perf_event *event, *sibling;
9364
	struct perf_event_attr attr;
P
Peter Zijlstra 已提交
9365
	struct perf_event_context *ctx, *uninitialized_var(gctx);
9366
	struct file *event_file = NULL;
9367
	struct fd group = {NULL, 0};
M
Matt Helsley 已提交
9368
	struct task_struct *task = NULL;
9369
	struct pmu *pmu;
9370
	int event_fd;
9371
	int move_group = 0;
9372
	int err;
9373
	int f_flags = O_RDWR;
9374
	int cgroup_fd = -1;
T
Thomas Gleixner 已提交
9375

9376
	/* for future expandability... */
S
Stephane Eranian 已提交
9377
	if (flags & ~PERF_FLAG_ALL)
9378 9379
		return -EINVAL;

9380 9381 9382
	err = perf_copy_attr(attr_uptr, &attr);
	if (err)
		return err;
9383

9384 9385 9386 9387 9388
	if (!attr.exclude_kernel) {
		if (perf_paranoid_kernel() && !capable(CAP_SYS_ADMIN))
			return -EACCES;
	}

9389
	if (attr.freq) {
9390
		if (attr.sample_freq > sysctl_perf_event_sample_rate)
9391
			return -EINVAL;
9392 9393 9394
	} else {
		if (attr.sample_period & (1ULL << 63))
			return -EINVAL;
9395 9396
	}

9397 9398 9399
	if (!attr.sample_max_stack)
		attr.sample_max_stack = sysctl_perf_event_max_stack;

S
Stephane Eranian 已提交
9400 9401 9402 9403 9404 9405 9406 9407 9408
	/*
	 * In cgroup mode, the pid argument is used to pass the fd
	 * opened to the cgroup directory in cgroupfs. The cpu argument
	 * designates the cpu on which to monitor threads from that
	 * cgroup.
	 */
	if ((flags & PERF_FLAG_PID_CGROUP) && (pid == -1 || cpu == -1))
		return -EINVAL;

9409 9410 9411 9412
	if (flags & PERF_FLAG_FD_CLOEXEC)
		f_flags |= O_CLOEXEC;

	event_fd = get_unused_fd_flags(f_flags);
9413 9414 9415
	if (event_fd < 0)
		return event_fd;

9416
	if (group_fd != -1) {
9417 9418
		err = perf_fget_light(group_fd, &group);
		if (err)
9419
			goto err_fd;
9420
		group_leader = group.file->private_data;
9421 9422 9423 9424 9425 9426
		if (flags & PERF_FLAG_FD_OUTPUT)
			output_event = group_leader;
		if (flags & PERF_FLAG_FD_NO_GROUP)
			group_leader = NULL;
	}

S
Stephane Eranian 已提交
9427
	if (pid != -1 && !(flags & PERF_FLAG_PID_CGROUP)) {
9428 9429 9430 9431 9432 9433 9434
		task = find_lively_task_by_vpid(pid);
		if (IS_ERR(task)) {
			err = PTR_ERR(task);
			goto err_group_fd;
		}
	}

9435 9436 9437 9438 9439 9440
	if (task && group_leader &&
	    group_leader->attr.inherit != attr.inherit) {
		err = -EINVAL;
		goto err_task;
	}

9441 9442
	get_online_cpus();

9443 9444 9445 9446 9447 9448 9449 9450 9451 9452 9453 9454 9455 9456 9457 9458 9459 9460
	if (task) {
		err = mutex_lock_interruptible(&task->signal->cred_guard_mutex);
		if (err)
			goto err_cpus;

		/*
		 * Reuse ptrace permission checks for now.
		 *
		 * We must hold cred_guard_mutex across this and any potential
		 * perf_install_in_context() call for this new event to
		 * serialize against exec() altering our credentials (and the
		 * perf_event_exit_task() that could imply).
		 */
		err = -EACCES;
		if (!ptrace_may_access(task, PTRACE_MODE_READ_REALCREDS))
			goto err_cred;
	}

9461 9462 9463
	if (flags & PERF_FLAG_PID_CGROUP)
		cgroup_fd = pid;

9464
	event = perf_event_alloc(&attr, cpu, task, group_leader, NULL,
9465
				 NULL, NULL, cgroup_fd);
9466 9467
	if (IS_ERR(event)) {
		err = PTR_ERR(event);
9468
		goto err_cred;
9469 9470
	}

9471 9472
	if (is_sampling_event(event)) {
		if (event->pmu->capabilities & PERF_PMU_CAP_NO_INTERRUPT) {
9473
			err = -EOPNOTSUPP;
9474 9475 9476 9477
			goto err_alloc;
		}
	}

9478 9479 9480 9481 9482
	/*
	 * Special case software events and allow them to be part of
	 * any hardware group.
	 */
	pmu = event->pmu;
9483

9484 9485 9486 9487 9488 9489
	if (attr.use_clockid) {
		err = perf_event_set_clock(event, attr.clockid);
		if (err)
			goto err_alloc;
	}

9490 9491 9492
	if (pmu->task_ctx_nr == perf_sw_context)
		event->event_caps |= PERF_EV_CAP_SOFTWARE;

9493 9494 9495 9496 9497 9498 9499 9500 9501 9502 9503 9504 9505
	if (group_leader &&
	    (is_software_event(event) != is_software_event(group_leader))) {
		if (is_software_event(event)) {
			/*
			 * If event and group_leader are not both a software
			 * event, and event is, then group leader is not.
			 *
			 * Allow the addition of software events to !software
			 * groups, this is safe because software events never
			 * fail to schedule.
			 */
			pmu = group_leader->pmu;
		} else if (is_software_event(group_leader) &&
9506
			   (group_leader->group_caps & PERF_EV_CAP_SOFTWARE)) {
9507 9508 9509 9510 9511 9512 9513 9514
			/*
			 * In case the group is a pure software group, and we
			 * try to add a hardware event, move the whole group to
			 * the hardware context.
			 */
			move_group = 1;
		}
	}
9515 9516 9517 9518

	/*
	 * Get the target context (task or percpu):
	 */
9519
	ctx = find_get_context(pmu, task, event);
9520 9521
	if (IS_ERR(ctx)) {
		err = PTR_ERR(ctx);
9522
		goto err_alloc;
9523 9524
	}

9525 9526 9527 9528 9529
	if ((pmu->capabilities & PERF_PMU_CAP_EXCLUSIVE) && group_leader) {
		err = -EBUSY;
		goto err_context;
	}

I
Ingo Molnar 已提交
9530
	/*
9531
	 * Look up the group leader (we will attach this event to it):
9532
	 */
9533
	if (group_leader) {
9534
		err = -EINVAL;
9535 9536

		/*
I
Ingo Molnar 已提交
9537 9538 9539 9540
		 * Do not allow a recursive hierarchy (this new sibling
		 * becoming part of another group-sibling):
		 */
		if (group_leader->group_leader != group_leader)
9541
			goto err_context;
9542 9543 9544 9545 9546

		/* All events in a group should have the same clock */
		if (group_leader->clock != event->clock)
			goto err_context;

I
Ingo Molnar 已提交
9547 9548 9549
		/*
		 * Do not allow to attach to a group in a different
		 * task or CPU context:
9550
		 */
9551
		if (move_group) {
9552 9553 9554 9555 9556 9557 9558 9559 9560 9561 9562 9563 9564
			/*
			 * Make sure we're both on the same task, or both
			 * per-cpu events.
			 */
			if (group_leader->ctx->task != ctx->task)
				goto err_context;

			/*
			 * Make sure we're both events for the same CPU;
			 * grouping events for different CPUs is broken; since
			 * you can never concurrently schedule them anyhow.
			 */
			if (group_leader->cpu != event->cpu)
9565 9566 9567 9568 9569 9570
				goto err_context;
		} else {
			if (group_leader->ctx != ctx)
				goto err_context;
		}

9571 9572 9573
		/*
		 * Only a group leader can be exclusive or pinned
		 */
9574
		if (attr.exclusive || attr.pinned)
9575
			goto err_context;
9576 9577 9578 9579 9580
	}

	if (output_event) {
		err = perf_event_set_output(event, output_event);
		if (err)
9581
			goto err_context;
9582
	}
T
Thomas Gleixner 已提交
9583

9584 9585
	event_file = anon_inode_getfile("[perf_event]", &perf_fops, event,
					f_flags);
9586 9587
	if (IS_ERR(event_file)) {
		err = PTR_ERR(event_file);
9588
		event_file = NULL;
9589
		goto err_context;
9590
	}
9591

9592
	if (move_group) {
P
Peter Zijlstra 已提交
9593
		gctx = group_leader->ctx;
9594
		mutex_lock_double(&gctx->mutex, &ctx->mutex);
9595 9596 9597 9598
		if (gctx->task == TASK_TOMBSTONE) {
			err = -ESRCH;
			goto err_locked;
		}
9599 9600 9601 9602
	} else {
		mutex_lock(&ctx->mutex);
	}

9603 9604 9605 9606 9607
	if (ctx->task == TASK_TOMBSTONE) {
		err = -ESRCH;
		goto err_locked;
	}

P
Peter Zijlstra 已提交
9608 9609 9610 9611 9612
	if (!perf_event_validate_size(event)) {
		err = -E2BIG;
		goto err_locked;
	}

9613 9614 9615 9616 9617 9618 9619
	/*
	 * Must be under the same ctx::mutex as perf_install_in_context(),
	 * because we need to serialize with concurrent event creation.
	 */
	if (!exclusive_event_installable(event, ctx)) {
		/* exclusive and group stuff are assumed mutually exclusive */
		WARN_ON_ONCE(move_group);
P
Peter Zijlstra 已提交
9620

9621 9622 9623
		err = -EBUSY;
		goto err_locked;
	}
P
Peter Zijlstra 已提交
9624

9625 9626
	WARN_ON_ONCE(ctx->parent_ctx);

9627 9628 9629 9630 9631
	/*
	 * This is the point on no return; we cannot fail hereafter. This is
	 * where we start modifying current state.
	 */

9632
	if (move_group) {
P
Peter Zijlstra 已提交
9633 9634 9635 9636
		/*
		 * See perf_event_ctx_lock() for comments on the details
		 * of swizzling perf_event::ctx.
		 */
9637
		perf_remove_from_context(group_leader, 0);
J
Jiri Olsa 已提交
9638

9639 9640
		list_for_each_entry(sibling, &group_leader->sibling_list,
				    group_entry) {
9641
			perf_remove_from_context(sibling, 0);
9642 9643 9644
			put_ctx(gctx);
		}

P
Peter Zijlstra 已提交
9645 9646 9647 9648
		/*
		 * Wait for everybody to stop referencing the events through
		 * the old lists, before installing it on new lists.
		 */
9649
		synchronize_rcu();
P
Peter Zijlstra 已提交
9650

9651 9652 9653 9654 9655 9656 9657 9658 9659 9660
		/*
		 * Install the group siblings before the group leader.
		 *
		 * Because a group leader will try and install the entire group
		 * (through the sibling list, which is still in-tact), we can
		 * end up with siblings installed in the wrong context.
		 *
		 * By installing siblings first we NO-OP because they're not
		 * reachable through the group lists.
		 */
9661 9662
		list_for_each_entry(sibling, &group_leader->sibling_list,
				    group_entry) {
9663
			perf_event__state_init(sibling);
9664
			perf_install_in_context(ctx, sibling, sibling->cpu);
9665 9666
			get_ctx(ctx);
		}
9667 9668 9669 9670 9671 9672 9673 9674 9675

		/*
		 * Removing from the context ends up with disabled
		 * event. What we want here is event in the initial
		 * startup state, ready to be add into new context.
		 */
		perf_event__state_init(group_leader);
		perf_install_in_context(ctx, group_leader, group_leader->cpu);
		get_ctx(ctx);
9676

9677 9678 9679 9680 9681 9682
		/*
		 * Now that all events are installed in @ctx, nothing
		 * references @gctx anymore, so drop the last reference we have
		 * on it.
		 */
		put_ctx(gctx);
9683 9684
	}

9685 9686 9687 9688 9689 9690 9691 9692 9693
	/*
	 * Precalculate sample_data sizes; do while holding ctx::mutex such
	 * that we're serialized against further additions and before
	 * perf_install_in_context() which is the point the event is active and
	 * can use these values.
	 */
	perf_event__header_size(event);
	perf_event__id_header_size(event);

P
Peter Zijlstra 已提交
9694 9695
	event->owner = current;

9696
	perf_install_in_context(ctx, event, event->cpu);
9697
	perf_unpin_context(ctx);
P
Peter Zijlstra 已提交
9698

9699
	if (move_group)
P
Peter Zijlstra 已提交
9700
		mutex_unlock(&gctx->mutex);
9701
	mutex_unlock(&ctx->mutex);
9702

9703 9704 9705 9706 9707
	if (task) {
		mutex_unlock(&task->signal->cred_guard_mutex);
		put_task_struct(task);
	}

9708 9709
	put_online_cpus();

9710 9711 9712
	mutex_lock(&current->perf_event_mutex);
	list_add_tail(&event->owner_entry, &current->perf_event_list);
	mutex_unlock(&current->perf_event_mutex);
9713

9714 9715 9716 9717 9718 9719
	/*
	 * Drop the reference on the group_event after placing the
	 * new event on the sibling_list. This ensures destruction
	 * of the group leader will find the pointer to itself in
	 * perf_group_detach().
	 */
9720
	fdput(group);
9721 9722
	fd_install(event_fd, event_file);
	return event_fd;
T
Thomas Gleixner 已提交
9723

9724 9725 9726 9727 9728 9729
err_locked:
	if (move_group)
		mutex_unlock(&gctx->mutex);
	mutex_unlock(&ctx->mutex);
/* err_file: */
	fput(event_file);
9730
err_context:
9731
	perf_unpin_context(ctx);
9732
	put_ctx(ctx);
9733
err_alloc:
P
Peter Zijlstra 已提交
9734 9735 9736 9737 9738 9739
	/*
	 * If event_file is set, the fput() above will have called ->release()
	 * and that will take care of freeing the event.
	 */
	if (!event_file)
		free_event(event);
9740 9741 9742
err_cred:
	if (task)
		mutex_unlock(&task->signal->cred_guard_mutex);
9743
err_cpus:
9744
	put_online_cpus();
9745
err_task:
P
Peter Zijlstra 已提交
9746 9747
	if (task)
		put_task_struct(task);
9748
err_group_fd:
9749
	fdput(group);
9750 9751
err_fd:
	put_unused_fd(event_fd);
9752
	return err;
T
Thomas Gleixner 已提交
9753 9754
}

9755 9756 9757 9758 9759
/**
 * perf_event_create_kernel_counter
 *
 * @attr: attributes of the counter to create
 * @cpu: cpu in which the counter is bound
M
Matt Helsley 已提交
9760
 * @task: task to profile (NULL for percpu)
9761 9762 9763
 */
struct perf_event *
perf_event_create_kernel_counter(struct perf_event_attr *attr, int cpu,
M
Matt Helsley 已提交
9764
				 struct task_struct *task,
9765 9766
				 perf_overflow_handler_t overflow_handler,
				 void *context)
9767 9768
{
	struct perf_event_context *ctx;
9769
	struct perf_event *event;
9770
	int err;
9771

9772 9773 9774
	/*
	 * Get the target context (task or percpu):
	 */
9775

9776
	event = perf_event_alloc(attr, cpu, task, NULL, NULL,
9777
				 overflow_handler, context, -1);
9778 9779 9780 9781
	if (IS_ERR(event)) {
		err = PTR_ERR(event);
		goto err;
	}
9782

9783
	/* Mark owner so we could distinguish it from user events. */
9784
	event->owner = TASK_TOMBSTONE;
9785

9786
	ctx = find_get_context(event->pmu, task, event);
9787 9788
	if (IS_ERR(ctx)) {
		err = PTR_ERR(ctx);
9789
		goto err_free;
9790
	}
9791 9792 9793

	WARN_ON_ONCE(ctx->parent_ctx);
	mutex_lock(&ctx->mutex);
9794 9795 9796 9797 9798
	if (ctx->task == TASK_TOMBSTONE) {
		err = -ESRCH;
		goto err_unlock;
	}

9799 9800
	if (!exclusive_event_installable(event, ctx)) {
		err = -EBUSY;
9801
		goto err_unlock;
9802 9803
	}

9804
	perf_install_in_context(ctx, event, cpu);
9805
	perf_unpin_context(ctx);
9806 9807 9808 9809
	mutex_unlock(&ctx->mutex);

	return event;

9810 9811 9812 9813
err_unlock:
	mutex_unlock(&ctx->mutex);
	perf_unpin_context(ctx);
	put_ctx(ctx);
9814 9815 9816
err_free:
	free_event(event);
err:
9817
	return ERR_PTR(err);
9818
}
9819
EXPORT_SYMBOL_GPL(perf_event_create_kernel_counter);
9820

9821 9822 9823 9824 9825 9826 9827 9828 9829 9830
void perf_pmu_migrate_context(struct pmu *pmu, int src_cpu, int dst_cpu)
{
	struct perf_event_context *src_ctx;
	struct perf_event_context *dst_ctx;
	struct perf_event *event, *tmp;
	LIST_HEAD(events);

	src_ctx = &per_cpu_ptr(pmu->pmu_cpu_context, src_cpu)->ctx;
	dst_ctx = &per_cpu_ptr(pmu->pmu_cpu_context, dst_cpu)->ctx;

P
Peter Zijlstra 已提交
9831 9832 9833 9834 9835
	/*
	 * See perf_event_ctx_lock() for comments on the details
	 * of swizzling perf_event::ctx.
	 */
	mutex_lock_double(&src_ctx->mutex, &dst_ctx->mutex);
9836 9837
	list_for_each_entry_safe(event, tmp, &src_ctx->event_list,
				 event_entry) {
9838
		perf_remove_from_context(event, 0);
9839
		unaccount_event_cpu(event, src_cpu);
9840
		put_ctx(src_ctx);
9841
		list_add(&event->migrate_entry, &events);
9842 9843
	}

9844 9845 9846
	/*
	 * Wait for the events to quiesce before re-instating them.
	 */
9847 9848
	synchronize_rcu();

9849 9850 9851 9852 9853 9854 9855 9856 9857 9858 9859 9860 9861 9862 9863 9864 9865 9866 9867 9868 9869 9870 9871 9872
	/*
	 * Re-instate events in 2 passes.
	 *
	 * Skip over group leaders and only install siblings on this first
	 * pass, siblings will not get enabled without a leader, however a
	 * leader will enable its siblings, even if those are still on the old
	 * context.
	 */
	list_for_each_entry_safe(event, tmp, &events, migrate_entry) {
		if (event->group_leader == event)
			continue;

		list_del(&event->migrate_entry);
		if (event->state >= PERF_EVENT_STATE_OFF)
			event->state = PERF_EVENT_STATE_INACTIVE;
		account_event_cpu(event, dst_cpu);
		perf_install_in_context(dst_ctx, event, dst_cpu);
		get_ctx(dst_ctx);
	}

	/*
	 * Once all the siblings are setup properly, install the group leaders
	 * to make it go.
	 */
9873 9874
	list_for_each_entry_safe(event, tmp, &events, migrate_entry) {
		list_del(&event->migrate_entry);
9875 9876
		if (event->state >= PERF_EVENT_STATE_OFF)
			event->state = PERF_EVENT_STATE_INACTIVE;
9877
		account_event_cpu(event, dst_cpu);
9878 9879 9880 9881
		perf_install_in_context(dst_ctx, event, dst_cpu);
		get_ctx(dst_ctx);
	}
	mutex_unlock(&dst_ctx->mutex);
P
Peter Zijlstra 已提交
9882
	mutex_unlock(&src_ctx->mutex);
9883 9884 9885
}
EXPORT_SYMBOL_GPL(perf_pmu_migrate_context);

9886
static void sync_child_event(struct perf_event *child_event,
9887
			       struct task_struct *child)
9888
{
9889
	struct perf_event *parent_event = child_event->parent;
9890
	u64 child_val;
9891

9892 9893
	if (child_event->attr.inherit_stat)
		perf_event_read_event(child_event, child);
9894

P
Peter Zijlstra 已提交
9895
	child_val = perf_event_count(child_event);
9896 9897 9898 9899

	/*
	 * Add back the child's count to the parent's count:
	 */
9900
	atomic64_add(child_val, &parent_event->child_count);
9901 9902 9903 9904
	atomic64_add(child_event->total_time_enabled,
		     &parent_event->child_total_time_enabled);
	atomic64_add(child_event->total_time_running,
		     &parent_event->child_total_time_running);
9905 9906
}

9907
static void
9908 9909 9910
perf_event_exit_event(struct perf_event *child_event,
		      struct perf_event_context *child_ctx,
		      struct task_struct *child)
9911
{
9912 9913
	struct perf_event *parent_event = child_event->parent;

9914 9915 9916 9917 9918 9919 9920 9921 9922 9923 9924 9925
	/*
	 * Do not destroy the 'original' grouping; because of the context
	 * switch optimization the original events could've ended up in a
	 * random child task.
	 *
	 * If we were to destroy the original group, all group related
	 * operations would cease to function properly after this random
	 * child dies.
	 *
	 * Do destroy all inherited groups, we don't care about those
	 * and being thorough is better.
	 */
9926 9927 9928
	raw_spin_lock_irq(&child_ctx->lock);
	WARN_ON_ONCE(child_ctx->is_active);

9929
	if (parent_event)
9930 9931
		perf_group_detach(child_event);
	list_del_event(child_event, child_ctx);
P
Peter Zijlstra 已提交
9932
	child_event->state = PERF_EVENT_STATE_EXIT; /* is_event_hup() */
9933
	raw_spin_unlock_irq(&child_ctx->lock);
9934

9935
	/*
9936
	 * Parent events are governed by their filedesc, retain them.
9937
	 */
9938
	if (!parent_event) {
9939
		perf_event_wakeup(child_event);
9940
		return;
9941
	}
9942 9943 9944 9945 9946 9947 9948 9949 9950 9951 9952 9953 9954 9955 9956 9957 9958 9959 9960 9961
	/*
	 * Child events can be cleaned up.
	 */

	sync_child_event(child_event, child);

	/*
	 * Remove this event from the parent's list
	 */
	WARN_ON_ONCE(parent_event->ctx->parent_ctx);
	mutex_lock(&parent_event->child_mutex);
	list_del_init(&child_event->child_list);
	mutex_unlock(&parent_event->child_mutex);

	/*
	 * Kick perf_poll() for is_event_hup().
	 */
	perf_event_wakeup(parent_event);
	free_event(child_event);
	put_event(parent_event);
9962 9963
}

P
Peter Zijlstra 已提交
9964
static void perf_event_exit_task_context(struct task_struct *child, int ctxn)
9965
{
9966
	struct perf_event_context *child_ctx, *clone_ctx = NULL;
9967 9968 9969
	struct perf_event *child_event, *next;

	WARN_ON_ONCE(child != current);
9970

9971
	child_ctx = perf_pin_task_context(child, ctxn);
9972
	if (!child_ctx)
9973 9974
		return;

9975
	/*
9976 9977 9978 9979 9980 9981 9982 9983
	 * In order to reduce the amount of tricky in ctx tear-down, we hold
	 * ctx::mutex over the entire thing. This serializes against almost
	 * everything that wants to access the ctx.
	 *
	 * The exception is sys_perf_event_open() /
	 * perf_event_create_kernel_count() which does find_get_context()
	 * without ctx::mutex (it cannot because of the move_group double mutex
	 * lock thing). See the comments in perf_install_in_context().
9984
	 */
9985
	mutex_lock(&child_ctx->mutex);
9986 9987

	/*
9988 9989 9990
	 * In a single ctx::lock section, de-schedule the events and detach the
	 * context from the task such that we cannot ever get it scheduled back
	 * in.
9991
	 */
9992
	raw_spin_lock_irq(&child_ctx->lock);
9993
	task_ctx_sched_out(__get_cpu_context(child_ctx), child_ctx);
9994

9995
	/*
9996 9997
	 * Now that the context is inactive, destroy the task <-> ctx relation
	 * and mark the context dead.
9998
	 */
9999 10000 10001 10002
	RCU_INIT_POINTER(child->perf_event_ctxp[ctxn], NULL);
	put_ctx(child_ctx); /* cannot be last */
	WRITE_ONCE(child_ctx->task, TASK_TOMBSTONE);
	put_task_struct(current); /* cannot be last */
10003

10004
	clone_ctx = unclone_ctx(child_ctx);
10005
	raw_spin_unlock_irq(&child_ctx->lock);
P
Peter Zijlstra 已提交
10006

10007 10008
	if (clone_ctx)
		put_ctx(clone_ctx);
10009

P
Peter Zijlstra 已提交
10010
	/*
10011 10012 10013
	 * Report the task dead after unscheduling the events so that we
	 * won't get any samples after PERF_RECORD_EXIT. We can however still
	 * get a few PERF_RECORD_READ events.
P
Peter Zijlstra 已提交
10014
	 */
10015
	perf_event_task(child, child_ctx, 0);
10016

10017
	list_for_each_entry_safe(child_event, next, &child_ctx->event_list, event_entry)
10018
		perf_event_exit_event(child_event, child_ctx, child);
10019

10020 10021 10022
	mutex_unlock(&child_ctx->mutex);

	put_ctx(child_ctx);
10023 10024
}

P
Peter Zijlstra 已提交
10025 10026
/*
 * When a child task exits, feed back event values to parent events.
10027 10028 10029
 *
 * Can be called with cred_guard_mutex held when called from
 * install_exec_creds().
P
Peter Zijlstra 已提交
10030 10031 10032
 */
void perf_event_exit_task(struct task_struct *child)
{
P
Peter Zijlstra 已提交
10033
	struct perf_event *event, *tmp;
P
Peter Zijlstra 已提交
10034 10035
	int ctxn;

P
Peter Zijlstra 已提交
10036 10037 10038 10039 10040 10041 10042 10043 10044 10045
	mutex_lock(&child->perf_event_mutex);
	list_for_each_entry_safe(event, tmp, &child->perf_event_list,
				 owner_entry) {
		list_del_init(&event->owner_entry);

		/*
		 * Ensure the list deletion is visible before we clear
		 * the owner, closes a race against perf_release() where
		 * we need to serialize on the owner->perf_event_mutex.
		 */
10046
		smp_store_release(&event->owner, NULL);
P
Peter Zijlstra 已提交
10047 10048 10049
	}
	mutex_unlock(&child->perf_event_mutex);

P
Peter Zijlstra 已提交
10050 10051
	for_each_task_context_nr(ctxn)
		perf_event_exit_task_context(child, ctxn);
J
Jiri Olsa 已提交
10052 10053 10054 10055 10056 10057 10058 10059

	/*
	 * The perf_event_exit_task_context calls perf_event_task
	 * with child's task_ctx, which generates EXIT events for
	 * child contexts and sets child->perf_event_ctxp[] to NULL.
	 * At this point we need to send EXIT events to cpu contexts.
	 */
	perf_event_task(child, NULL, 0);
P
Peter Zijlstra 已提交
10060 10061
}

10062 10063 10064 10065 10066 10067 10068 10069 10070 10071 10072 10073
static void perf_free_event(struct perf_event *event,
			    struct perf_event_context *ctx)
{
	struct perf_event *parent = event->parent;

	if (WARN_ON_ONCE(!parent))
		return;

	mutex_lock(&parent->child_mutex);
	list_del_init(&event->child_list);
	mutex_unlock(&parent->child_mutex);

10074
	put_event(parent);
10075

P
Peter Zijlstra 已提交
10076
	raw_spin_lock_irq(&ctx->lock);
10077
	perf_group_detach(event);
10078
	list_del_event(event, ctx);
P
Peter Zijlstra 已提交
10079
	raw_spin_unlock_irq(&ctx->lock);
10080 10081 10082
	free_event(event);
}

10083
/*
P
Peter Zijlstra 已提交
10084
 * Free an unexposed, unused context as created by inheritance by
P
Peter Zijlstra 已提交
10085
 * perf_event_init_task below, used by fork() in case of fail.
P
Peter Zijlstra 已提交
10086 10087 10088
 *
 * Not all locks are strictly required, but take them anyway to be nice and
 * help out with the lockdep assertions.
10089
 */
10090
void perf_event_free_task(struct task_struct *task)
10091
{
P
Peter Zijlstra 已提交
10092
	struct perf_event_context *ctx;
10093
	struct perf_event *event, *tmp;
P
Peter Zijlstra 已提交
10094
	int ctxn;
10095

P
Peter Zijlstra 已提交
10096 10097 10098 10099
	for_each_task_context_nr(ctxn) {
		ctx = task->perf_event_ctxp[ctxn];
		if (!ctx)
			continue;
10100

P
Peter Zijlstra 已提交
10101
		mutex_lock(&ctx->mutex);
10102
again:
P
Peter Zijlstra 已提交
10103 10104 10105
		list_for_each_entry_safe(event, tmp, &ctx->pinned_groups,
				group_entry)
			perf_free_event(event, ctx);
10106

P
Peter Zijlstra 已提交
10107 10108 10109
		list_for_each_entry_safe(event, tmp, &ctx->flexible_groups,
				group_entry)
			perf_free_event(event, ctx);
10110

P
Peter Zijlstra 已提交
10111 10112 10113
		if (!list_empty(&ctx->pinned_groups) ||
				!list_empty(&ctx->flexible_groups))
			goto again;
10114

P
Peter Zijlstra 已提交
10115
		mutex_unlock(&ctx->mutex);
10116

P
Peter Zijlstra 已提交
10117 10118
		put_ctx(ctx);
	}
10119 10120
}

10121 10122 10123 10124 10125 10126 10127 10128
void perf_event_delayed_put(struct task_struct *task)
{
	int ctxn;

	for_each_task_context_nr(ctxn)
		WARN_ON_ONCE(task->perf_event_ctxp[ctxn]);
}

10129
struct file *perf_event_get(unsigned int fd)
10130
{
10131
	struct file *file;
10132

10133 10134 10135
	file = fget_raw(fd);
	if (!file)
		return ERR_PTR(-EBADF);
10136

10137 10138 10139 10140
	if (file->f_op != &perf_fops) {
		fput(file);
		return ERR_PTR(-EBADF);
	}
10141

10142
	return file;
10143 10144 10145 10146 10147 10148 10149 10150 10151 10152
}

const struct perf_event_attr *perf_event_attrs(struct perf_event *event)
{
	if (!event)
		return ERR_PTR(-EINVAL);

	return &event->attr;
}

P
Peter Zijlstra 已提交
10153 10154 10155 10156 10157 10158 10159 10160 10161 10162 10163
/*
 * inherit a event from parent task to child task:
 */
static struct perf_event *
inherit_event(struct perf_event *parent_event,
	      struct task_struct *parent,
	      struct perf_event_context *parent_ctx,
	      struct task_struct *child,
	      struct perf_event *group_leader,
	      struct perf_event_context *child_ctx)
{
10164
	enum perf_event_active_state parent_state = parent_event->state;
P
Peter Zijlstra 已提交
10165
	struct perf_event *child_event;
10166
	unsigned long flags;
P
Peter Zijlstra 已提交
10167 10168 10169 10170 10171 10172 10173 10174 10175 10176 10177 10178

	/*
	 * Instead of creating recursive hierarchies of events,
	 * we link inherited events back to the original parent,
	 * which has a filp for sure, which we use as the reference
	 * count:
	 */
	if (parent_event->parent)
		parent_event = parent_event->parent;

	child_event = perf_event_alloc(&parent_event->attr,
					   parent_event->cpu,
10179
					   child,
P
Peter Zijlstra 已提交
10180
					   group_leader, parent_event,
10181
					   NULL, NULL, -1);
P
Peter Zijlstra 已提交
10182 10183
	if (IS_ERR(child_event))
		return child_event;
10184

10185 10186 10187 10188 10189 10190 10191
	/*
	 * is_orphaned_event() and list_add_tail(&parent_event->child_list)
	 * must be under the same lock in order to serialize against
	 * perf_event_release_kernel(), such that either we must observe
	 * is_orphaned_event() or they will observe us on the child_list.
	 */
	mutex_lock(&parent_event->child_mutex);
10192 10193
	if (is_orphaned_event(parent_event) ||
	    !atomic_long_inc_not_zero(&parent_event->refcount)) {
10194
		mutex_unlock(&parent_event->child_mutex);
10195 10196 10197 10198
		free_event(child_event);
		return NULL;
	}

P
Peter Zijlstra 已提交
10199 10200 10201 10202 10203 10204 10205
	get_ctx(child_ctx);

	/*
	 * Make the child state follow the state of the parent event,
	 * not its attr.disabled bit.  We hold the parent's mutex,
	 * so we won't race with perf_event_{en, dis}able_family.
	 */
10206
	if (parent_state >= PERF_EVENT_STATE_INACTIVE)
P
Peter Zijlstra 已提交
10207 10208 10209 10210 10211 10212 10213 10214 10215 10216 10217 10218 10219 10220 10221 10222
		child_event->state = PERF_EVENT_STATE_INACTIVE;
	else
		child_event->state = PERF_EVENT_STATE_OFF;

	if (parent_event->attr.freq) {
		u64 sample_period = parent_event->hw.sample_period;
		struct hw_perf_event *hwc = &child_event->hw;

		hwc->sample_period = sample_period;
		hwc->last_period   = sample_period;

		local64_set(&hwc->period_left, sample_period);
	}

	child_event->ctx = child_ctx;
	child_event->overflow_handler = parent_event->overflow_handler;
10223 10224
	child_event->overflow_handler_context
		= parent_event->overflow_handler_context;
P
Peter Zijlstra 已提交
10225

10226 10227 10228 10229
	/*
	 * Precalculate sample_data sizes
	 */
	perf_event__header_size(child_event);
10230
	perf_event__id_header_size(child_event);
10231

P
Peter Zijlstra 已提交
10232 10233 10234
	/*
	 * Link it up in the child's context:
	 */
10235
	raw_spin_lock_irqsave(&child_ctx->lock, flags);
P
Peter Zijlstra 已提交
10236
	add_event_to_ctx(child_event, child_ctx);
10237
	raw_spin_unlock_irqrestore(&child_ctx->lock, flags);
P
Peter Zijlstra 已提交
10238 10239 10240 10241 10242 10243 10244 10245 10246 10247 10248 10249 10250 10251 10252 10253 10254 10255 10256 10257 10258 10259 10260 10261 10262 10263 10264 10265 10266 10267 10268

	/*
	 * Link this into the parent event's child list
	 */
	list_add_tail(&child_event->child_list, &parent_event->child_list);
	mutex_unlock(&parent_event->child_mutex);

	return child_event;
}

static int inherit_group(struct perf_event *parent_event,
	      struct task_struct *parent,
	      struct perf_event_context *parent_ctx,
	      struct task_struct *child,
	      struct perf_event_context *child_ctx)
{
	struct perf_event *leader;
	struct perf_event *sub;
	struct perf_event *child_ctr;

	leader = inherit_event(parent_event, parent, parent_ctx,
				 child, NULL, child_ctx);
	if (IS_ERR(leader))
		return PTR_ERR(leader);
	list_for_each_entry(sub, &parent_event->sibling_list, group_entry) {
		child_ctr = inherit_event(sub, parent, parent_ctx,
					    child, leader, child_ctx);
		if (IS_ERR(child_ctr))
			return PTR_ERR(child_ctr);
	}
	return 0;
10269 10270 10271 10272 10273
}

static int
inherit_task_group(struct perf_event *event, struct task_struct *parent,
		   struct perf_event_context *parent_ctx,
P
Peter Zijlstra 已提交
10274
		   struct task_struct *child, int ctxn,
10275 10276 10277
		   int *inherited_all)
{
	int ret;
P
Peter Zijlstra 已提交
10278
	struct perf_event_context *child_ctx;
10279 10280 10281 10282

	if (!event->attr.inherit) {
		*inherited_all = 0;
		return 0;
10283 10284
	}

10285
	child_ctx = child->perf_event_ctxp[ctxn];
10286 10287 10288 10289 10290 10291 10292
	if (!child_ctx) {
		/*
		 * This is executed from the parent task context, so
		 * inherit events that have been marked for cloning.
		 * First allocate and initialize a context for the
		 * child.
		 */
10293

10294
		child_ctx = alloc_perf_context(parent_ctx->pmu, child);
10295 10296
		if (!child_ctx)
			return -ENOMEM;
10297

P
Peter Zijlstra 已提交
10298
		child->perf_event_ctxp[ctxn] = child_ctx;
10299 10300 10301 10302 10303 10304 10305 10306 10307
	}

	ret = inherit_group(event, parent, parent_ctx,
			    child, child_ctx);

	if (ret)
		*inherited_all = 0;

	return ret;
10308 10309
}

10310
/*
10311
 * Initialize the perf_event context in task_struct
10312
 */
10313
static int perf_event_init_context(struct task_struct *child, int ctxn)
10314
{
10315
	struct perf_event_context *child_ctx, *parent_ctx;
10316 10317
	struct perf_event_context *cloned_ctx;
	struct perf_event *event;
10318
	struct task_struct *parent = current;
10319
	int inherited_all = 1;
10320
	unsigned long flags;
10321
	int ret = 0;
10322

P
Peter Zijlstra 已提交
10323
	if (likely(!parent->perf_event_ctxp[ctxn]))
10324 10325
		return 0;

10326
	/*
10327 10328
	 * If the parent's context is a clone, pin it so it won't get
	 * swapped under us.
10329
	 */
P
Peter Zijlstra 已提交
10330
	parent_ctx = perf_pin_task_context(parent, ctxn);
10331 10332
	if (!parent_ctx)
		return 0;
10333

10334 10335 10336 10337 10338 10339 10340
	/*
	 * No need to check if parent_ctx != NULL here; since we saw
	 * it non-NULL earlier, the only reason for it to become NULL
	 * is if we exit, and since we're currently in the middle of
	 * a fork we can't be exiting at the same time.
	 */

10341 10342 10343 10344
	/*
	 * Lock the parent list. No need to lock the child - not PID
	 * hashed yet and not running, so nobody can access it.
	 */
10345
	mutex_lock(&parent_ctx->mutex);
10346 10347 10348 10349 10350

	/*
	 * We dont have to disable NMIs - we are only looking at
	 * the list, not manipulating it:
	 */
10351
	list_for_each_entry(event, &parent_ctx->pinned_groups, group_entry) {
P
Peter Zijlstra 已提交
10352 10353
		ret = inherit_task_group(event, parent, parent_ctx,
					 child, ctxn, &inherited_all);
10354 10355 10356
		if (ret)
			break;
	}
10357

10358 10359 10360 10361 10362 10363 10364 10365 10366
	/*
	 * We can't hold ctx->lock when iterating the ->flexible_group list due
	 * to allocations, but we need to prevent rotation because
	 * rotate_ctx() will change the list from interrupt context.
	 */
	raw_spin_lock_irqsave(&parent_ctx->lock, flags);
	parent_ctx->rotate_disable = 1;
	raw_spin_unlock_irqrestore(&parent_ctx->lock, flags);

10367
	list_for_each_entry(event, &parent_ctx->flexible_groups, group_entry) {
P
Peter Zijlstra 已提交
10368 10369
		ret = inherit_task_group(event, parent, parent_ctx,
					 child, ctxn, &inherited_all);
10370
		if (ret)
10371
			break;
10372 10373
	}

10374 10375 10376
	raw_spin_lock_irqsave(&parent_ctx->lock, flags);
	parent_ctx->rotate_disable = 0;

P
Peter Zijlstra 已提交
10377
	child_ctx = child->perf_event_ctxp[ctxn];
10378

10379
	if (child_ctx && inherited_all) {
10380 10381 10382
		/*
		 * Mark the child context as a clone of the parent
		 * context, or of whatever the parent is a clone of.
P
Peter Zijlstra 已提交
10383 10384 10385
		 *
		 * Note that if the parent is a clone, the holding of
		 * parent_ctx->lock avoids it from being uncloned.
10386
		 */
P
Peter Zijlstra 已提交
10387
		cloned_ctx = parent_ctx->parent_ctx;
10388 10389
		if (cloned_ctx) {
			child_ctx->parent_ctx = cloned_ctx;
10390
			child_ctx->parent_gen = parent_ctx->parent_gen;
10391 10392 10393 10394 10395
		} else {
			child_ctx->parent_ctx = parent_ctx;
			child_ctx->parent_gen = parent_ctx->generation;
		}
		get_ctx(child_ctx->parent_ctx);
10396 10397
	}

P
Peter Zijlstra 已提交
10398
	raw_spin_unlock_irqrestore(&parent_ctx->lock, flags);
10399
	mutex_unlock(&parent_ctx->mutex);
10400

10401
	perf_unpin_context(parent_ctx);
10402
	put_ctx(parent_ctx);
10403

10404
	return ret;
10405 10406
}

P
Peter Zijlstra 已提交
10407 10408 10409 10410 10411 10412 10413
/*
 * Initialize the perf_event context in task_struct
 */
int perf_event_init_task(struct task_struct *child)
{
	int ctxn, ret;

10414 10415 10416 10417
	memset(child->perf_event_ctxp, 0, sizeof(child->perf_event_ctxp));
	mutex_init(&child->perf_event_mutex);
	INIT_LIST_HEAD(&child->perf_event_list);

P
Peter Zijlstra 已提交
10418 10419
	for_each_task_context_nr(ctxn) {
		ret = perf_event_init_context(child, ctxn);
P
Peter Zijlstra 已提交
10420 10421
		if (ret) {
			perf_event_free_task(child);
P
Peter Zijlstra 已提交
10422
			return ret;
P
Peter Zijlstra 已提交
10423
		}
P
Peter Zijlstra 已提交
10424 10425 10426 10427 10428
	}

	return 0;
}

10429 10430
static void __init perf_event_init_all_cpus(void)
{
10431
	struct swevent_htable *swhash;
10432 10433 10434
	int cpu;

	for_each_possible_cpu(cpu) {
10435 10436
		swhash = &per_cpu(swevent_htable, cpu);
		mutex_init(&swhash->hlist_mutex);
10437
		INIT_LIST_HEAD(&per_cpu(active_ctx_list, cpu));
10438 10439 10440

		INIT_LIST_HEAD(&per_cpu(pmu_sb_events.list, cpu));
		raw_spin_lock_init(&per_cpu(pmu_sb_events.lock, cpu));
10441 10442

		INIT_LIST_HEAD(&per_cpu(sched_cb_list, cpu));
10443 10444 10445
	}
}

10446
int perf_event_init_cpu(unsigned int cpu)
T
Thomas Gleixner 已提交
10447
{
P
Peter Zijlstra 已提交
10448
	struct swevent_htable *swhash = &per_cpu(swevent_htable, cpu);
T
Thomas Gleixner 已提交
10449

10450
	mutex_lock(&swhash->hlist_mutex);
10451
	if (swhash->hlist_refcount > 0 && !swevent_hlist_deref(swhash)) {
10452 10453
		struct swevent_hlist *hlist;

10454 10455 10456
		hlist = kzalloc_node(sizeof(*hlist), GFP_KERNEL, cpu_to_node(cpu));
		WARN_ON(!hlist);
		rcu_assign_pointer(swhash->swevent_hlist, hlist);
10457
	}
10458
	mutex_unlock(&swhash->hlist_mutex);
10459
	return 0;
T
Thomas Gleixner 已提交
10460 10461
}

10462
#if defined CONFIG_HOTPLUG_CPU || defined CONFIG_KEXEC_CORE
P
Peter Zijlstra 已提交
10463
static void __perf_event_exit_context(void *__info)
T
Thomas Gleixner 已提交
10464
{
P
Peter Zijlstra 已提交
10465
	struct perf_event_context *ctx = __info;
10466 10467
	struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
	struct perf_event *event;
T
Thomas Gleixner 已提交
10468

10469 10470
	raw_spin_lock(&ctx->lock);
	list_for_each_entry(event, &ctx->event_list, event_entry)
10471
		__perf_remove_from_context(event, cpuctx, ctx, (void *)DETACH_GROUP);
10472
	raw_spin_unlock(&ctx->lock);
T
Thomas Gleixner 已提交
10473
}
P
Peter Zijlstra 已提交
10474 10475 10476 10477 10478 10479 10480 10481 10482

static void perf_event_exit_cpu_context(int cpu)
{
	struct perf_event_context *ctx;
	struct pmu *pmu;
	int idx;

	idx = srcu_read_lock(&pmus_srcu);
	list_for_each_entry_rcu(pmu, &pmus, entry) {
10483
		ctx = &per_cpu_ptr(pmu->pmu_cpu_context, cpu)->ctx;
P
Peter Zijlstra 已提交
10484 10485 10486 10487 10488 10489 10490

		mutex_lock(&ctx->mutex);
		smp_call_function_single(cpu, __perf_event_exit_context, ctx, 1);
		mutex_unlock(&ctx->mutex);
	}
	srcu_read_unlock(&pmus_srcu, idx);
}
10491 10492 10493 10494 10495
#else

static void perf_event_exit_cpu_context(int cpu) { }

#endif
P
Peter Zijlstra 已提交
10496

10497
int perf_event_exit_cpu(unsigned int cpu)
T
Thomas Gleixner 已提交
10498
{
P
Peter Zijlstra 已提交
10499
	perf_event_exit_cpu_context(cpu);
10500
	return 0;
T
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10501 10502
}

P
Peter Zijlstra 已提交
10503 10504 10505 10506 10507 10508 10509 10510 10511 10512 10513 10514 10515 10516 10517 10518 10519 10520 10521 10522
static int
perf_reboot(struct notifier_block *notifier, unsigned long val, void *v)
{
	int cpu;

	for_each_online_cpu(cpu)
		perf_event_exit_cpu(cpu);

	return NOTIFY_OK;
}

/*
 * Run the perf reboot notifier at the very last possible moment so that
 * the generic watchdog code runs as long as possible.
 */
static struct notifier_block perf_reboot_notifier = {
	.notifier_call = perf_reboot,
	.priority = INT_MIN,
};

10523
void __init perf_event_init(void)
T
Thomas Gleixner 已提交
10524
{
10525 10526
	int ret;

P
Peter Zijlstra 已提交
10527 10528
	idr_init(&pmu_idr);

10529
	perf_event_init_all_cpus();
10530
	init_srcu_struct(&pmus_srcu);
P
Peter Zijlstra 已提交
10531 10532 10533
	perf_pmu_register(&perf_swevent, "software", PERF_TYPE_SOFTWARE);
	perf_pmu_register(&perf_cpu_clock, NULL, -1);
	perf_pmu_register(&perf_task_clock, NULL, -1);
10534
	perf_tp_register();
10535
	perf_event_init_cpu(smp_processor_id());
P
Peter Zijlstra 已提交
10536
	register_reboot_notifier(&perf_reboot_notifier);
10537 10538 10539

	ret = init_hw_breakpoint();
	WARN(ret, "hw_breakpoint initialization failed with: %d", ret);
10540

10541 10542 10543 10544 10545 10546
	/*
	 * Build time assertion that we keep the data_head at the intended
	 * location.  IOW, validation we got the __reserved[] size right.
	 */
	BUILD_BUG_ON((offsetof(struct perf_event_mmap_page, data_head))
		     != 1024);
T
Thomas Gleixner 已提交
10547
}
P
Peter Zijlstra 已提交
10548

10549 10550 10551 10552 10553 10554 10555 10556 10557 10558 10559
ssize_t perf_event_sysfs_show(struct device *dev, struct device_attribute *attr,
			      char *page)
{
	struct perf_pmu_events_attr *pmu_attr =
		container_of(attr, struct perf_pmu_events_attr, attr);

	if (pmu_attr->event_str)
		return sprintf(page, "%s\n", pmu_attr->event_str);

	return 0;
}
10560
EXPORT_SYMBOL_GPL(perf_event_sysfs_show);
10561

P
Peter Zijlstra 已提交
10562 10563 10564 10565 10566 10567 10568 10569 10570 10571 10572 10573 10574 10575 10576 10577 10578 10579 10580 10581 10582 10583 10584 10585 10586 10587 10588
static int __init perf_event_sysfs_init(void)
{
	struct pmu *pmu;
	int ret;

	mutex_lock(&pmus_lock);

	ret = bus_register(&pmu_bus);
	if (ret)
		goto unlock;

	list_for_each_entry(pmu, &pmus, entry) {
		if (!pmu->name || pmu->type < 0)
			continue;

		ret = pmu_dev_alloc(pmu);
		WARN(ret, "Failed to register pmu: %s, reason %d\n", pmu->name, ret);
	}
	pmu_bus_running = 1;
	ret = 0;

unlock:
	mutex_unlock(&pmus_lock);

	return ret;
}
device_initcall(perf_event_sysfs_init);
S
Stephane Eranian 已提交
10589 10590

#ifdef CONFIG_CGROUP_PERF
10591 10592
static struct cgroup_subsys_state *
perf_cgroup_css_alloc(struct cgroup_subsys_state *parent_css)
S
Stephane Eranian 已提交
10593 10594 10595
{
	struct perf_cgroup *jc;

10596
	jc = kzalloc(sizeof(*jc), GFP_KERNEL);
S
Stephane Eranian 已提交
10597 10598 10599 10600 10601 10602 10603 10604 10605 10606 10607 10608
	if (!jc)
		return ERR_PTR(-ENOMEM);

	jc->info = alloc_percpu(struct perf_cgroup_info);
	if (!jc->info) {
		kfree(jc);
		return ERR_PTR(-ENOMEM);
	}

	return &jc->css;
}

10609
static void perf_cgroup_css_free(struct cgroup_subsys_state *css)
S
Stephane Eranian 已提交
10610
{
10611 10612
	struct perf_cgroup *jc = container_of(css, struct perf_cgroup, css);

S
Stephane Eranian 已提交
10613 10614 10615 10616 10617 10618 10619
	free_percpu(jc->info);
	kfree(jc);
}

static int __perf_cgroup_move(void *info)
{
	struct task_struct *task = info;
10620
	rcu_read_lock();
S
Stephane Eranian 已提交
10621
	perf_cgroup_switch(task, PERF_CGROUP_SWOUT | PERF_CGROUP_SWIN);
10622
	rcu_read_unlock();
S
Stephane Eranian 已提交
10623 10624 10625
	return 0;
}

10626
static void perf_cgroup_attach(struct cgroup_taskset *tset)
S
Stephane Eranian 已提交
10627
{
10628
	struct task_struct *task;
10629
	struct cgroup_subsys_state *css;
10630

10631
	cgroup_taskset_for_each(task, css, tset)
10632
		task_function_call(task, __perf_cgroup_move, task);
S
Stephane Eranian 已提交
10633 10634
}

10635
struct cgroup_subsys perf_event_cgrp_subsys = {
10636 10637
	.css_alloc	= perf_cgroup_css_alloc,
	.css_free	= perf_cgroup_css_free,
10638
	.attach		= perf_cgroup_attach,
S
Stephane Eranian 已提交
10639 10640
};
#endif /* CONFIG_CGROUP_PERF */