core.c 247.4 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_local(struct perf_event *event, event_f func, void *data)
{
	struct event_function_struct efs = {
		.event = event,
		.func = func,
		.data = data,
	};

	int ret = event_function(&efs);
	WARN_ON_ONCE(ret);
}

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

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	cgrp = perf_cgroup_from_task(current, event->ctx);
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	/*
	 * 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
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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;

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	/*
	 * 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;

640
	cgrp = perf_cgroup_from_task(task, ctx);
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	info = this_cpu_ptr(cgrp->info);
642
	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
 */
654
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);
674 675
		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) {
685 686
			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) {
698
				WARN_ON_ONCE(cpuctx->cgrp);
699 700 701 702
				/*
				 * set cgrp before ctxsw in to allow
				 * event_filter_match() to not have to pass
				 * task around
703 704
				 * we pass the cpuctx->ctx to perf_cgroup_from_task()
				 * because cgorup events are only per-cpu
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				 */
706
				cpuctx->cgrp = perf_cgroup_from_task(task, &cpuctx->ctx);
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				cpu_ctx_sched_in(cpuctx, EVENT_ALL, task);
			}
709 710
			perf_pmu_enable(cpuctx->ctx.pmu);
			perf_ctx_unlock(cpuctx, cpuctx->task_ctx);
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		}
	}

	local_irq_restore(flags);
}

717 718
static inline void perf_cgroup_sched_out(struct task_struct *task,
					 struct task_struct *next)
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{
720 721 722
	struct perf_cgroup *cgrp1;
	struct perf_cgroup *cgrp2 = NULL;

723
	rcu_read_lock();
724 725
	/*
	 * we come here when we know perf_cgroup_events > 0
726 727
	 * we do not need to pass the ctx here because we know
	 * we are holding the rcu lock
728
	 */
729
	cgrp1 = perf_cgroup_from_task(task, NULL);
730
	cgrp2 = perf_cgroup_from_task(next, NULL);
731 732 733 734 735 736 737 738

	/*
	 * 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);
739 740

	rcu_read_unlock();
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}

743 744
static inline void perf_cgroup_sched_in(struct task_struct *prev,
					struct task_struct *task)
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{
746 747 748
	struct perf_cgroup *cgrp1;
	struct perf_cgroup *cgrp2 = NULL;

749
	rcu_read_lock();
750 751
	/*
	 * we come here when we know perf_cgroup_events > 0
752 753
	 * we do not need to pass the ctx here because we know
	 * we are holding the rcu lock
754
	 */
755 756
	cgrp1 = perf_cgroup_from_task(task, NULL);
	cgrp2 = perf_cgroup_from_task(prev, NULL);
757 758 759 760 761 762 763 764

	/*
	 * 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);
765 766

	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;
775 776
	struct fd f = fdget(fd);
	int ret = 0;
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778
	if (!f.file)
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		return -EBADF;

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	css = css_tryget_online_from_dir(f.file->f_path.dentry,
782
					 &perf_event_cgrp_subsys);
783 784 785 786
	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;
	}
800
out:
801
	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;
		}
	}
}
846 847 848 849 850 851 852 853 854 855 856 857 858 859 860 861 862 863 864 865 866 867 868 869 870 871

/*
 * 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)
{
}

901 902
static inline void perf_cgroup_sched_out(struct task_struct *task,
					 struct task_struct *next)
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903 904 905
{
}

906 907
static inline void perf_cgroup_sched_in(struct task_struct *prev,
					struct task_struct *task)
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{
}

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
919 920
perf_cgroup_set_timestamp(struct task_struct *task,
			  struct perf_event_context *ctx)
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{
}

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)
{
}
949 950 951 952 953 954 955

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

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#endif

958 959 960 961 962 963 964 965
/*
 * 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
 */
966
static enum hrtimer_restart perf_mux_hrtimer_handler(struct hrtimer *hr)
967 968 969 970 971 972 973 974 975
{
	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)
978
		hrtimer_forward_now(hr, cpuctx->hrtimer_interval);
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	else
		cpuctx->hrtimer_active = 0;
	raw_spin_unlock(&cpuctx->hrtimer_lock);
982

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	return rotations ? HRTIMER_RESTART : HRTIMER_NORESTART;
984 985
}

986
static void __perf_mux_hrtimer_init(struct perf_cpu_context *cpuctx, int cpu)
987
{
988
	struct hrtimer *timer = &cpuctx->hrtimer;
989
	struct pmu *pmu = cpuctx->ctx.pmu;
990
	u64 interval;
991 992 993 994 995

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

996 997 998 999
	/*
	 * check default is sane, if not set then force to
	 * default interval (1/tick)
	 */
1000 1001 1002
	interval = pmu->hrtimer_interval_ms;
	if (interval < 1)
		interval = pmu->hrtimer_interval_ms = PERF_CPU_HRTIMER;
1003

1004
	cpuctx->hrtimer_interval = ns_to_ktime(NSEC_PER_MSEC * interval);
1005

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	raw_spin_lock_init(&cpuctx->hrtimer_lock);
	hrtimer_init(timer, CLOCK_MONOTONIC, HRTIMER_MODE_ABS_PINNED);
1008
	timer->function = perf_mux_hrtimer_handler;
1009 1010
}

1011
static int perf_mux_hrtimer_restart(struct perf_cpu_context *cpuctx)
1012
{
1013
	struct hrtimer *timer = &cpuctx->hrtimer;
1014
	struct pmu *pmu = cpuctx->ctx.pmu;
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1015
	unsigned long flags;
1016 1017 1018

	/* not for SW PMU */
	if (pmu->task_ctx_nr == perf_sw_context)
1019
		return 0;
1020

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1021 1022 1023 1024 1025 1026 1027
	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);
1028

1029
	return 0;
1030 1031
}

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1032
void perf_pmu_disable(struct pmu *pmu)
1033
{
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1034 1035 1036
	int *count = this_cpu_ptr(pmu->pmu_disable_count);
	if (!(*count)++)
		pmu->pmu_disable(pmu);
1037 1038
}

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1039
void perf_pmu_enable(struct pmu *pmu)
1040
{
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1041 1042 1043
	int *count = this_cpu_ptr(pmu->pmu_disable_count);
	if (!--(*count))
		pmu->pmu_enable(pmu);
1044 1045
}

1046
static DEFINE_PER_CPU(struct list_head, active_ctx_list);
1047 1048

/*
1049 1050 1051 1052
 * 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.
1053
 */
1054
static void perf_event_ctx_activate(struct perf_event_context *ctx)
1055
{
1056
	struct list_head *head = this_cpu_ptr(&active_ctx_list);
1057

1058
	WARN_ON(!irqs_disabled());
1059

1060 1061 1062 1063 1064 1065 1066 1067 1068 1069 1070 1071
	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);
1072 1073
}

1074
static void get_ctx(struct perf_event_context *ctx)
1075
{
1076
	WARN_ON(!atomic_inc_not_zero(&ctx->refcount));
1077 1078
}

1079 1080 1081 1082 1083 1084 1085 1086 1087
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);
}

1088
static void put_ctx(struct perf_event_context *ctx)
1089
{
1090 1091 1092
	if (atomic_dec_and_test(&ctx->refcount)) {
		if (ctx->parent_ctx)
			put_ctx(ctx->parent_ctx);
1093
		if (ctx->task && ctx->task != TASK_TOMBSTONE)
1094
			put_task_struct(ctx->task);
1095
		call_rcu(&ctx->rcu_head, free_ctx);
1096
	}
1097 1098
}

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1099 1100 1101 1102 1103 1104 1105
/*
 * 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.
 *
1106 1107 1108 1109
 * 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 ]
1110 1111
 *      perf_event_exit_event()
 *        put_event()			[ parent, 1 ]
1112 1113 1114 1115 1116 1117 1118 1119 1120 1121 1122 1123 1124 1125 1126 1127 1128
 *
 *  - 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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1129 1130 1131 1132 1133 1134 1135 1136 1137 1138 1139 1140 1141 1142 1143 1144 1145 1146 1147 1148 1149 1150 1151
 *
 * 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:
1152
 *    cred_guard_mutex
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 *	task_struct::perf_event_mutex
 *	  perf_event_context::mutex
 *	    perf_event::child_mutex;
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 *	      perf_event_context::lock
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1157 1158 1159
 *	    perf_event::mmap_mutex
 *	    mmap_sem
 */
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static struct perf_event_context *
perf_event_ctx_lock_nested(struct perf_event *event, int nesting)
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1162 1163 1164 1165 1166 1167 1168 1169 1170 1171 1172 1173
{
	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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1174
	mutex_lock_nested(&ctx->mutex, nesting);
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1175 1176 1177 1178 1179 1180 1181 1182 1183
	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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static void perf_event_ctx_unlock(struct perf_event *event,
				  struct perf_event_context *ctx)
{
	mutex_unlock(&ctx->mutex);
	put_ctx(ctx);
}

1197 1198 1199 1200 1201 1202 1203
/*
 * 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)
1204
{
1205 1206 1207 1208 1209
	struct perf_event_context *parent_ctx = ctx->parent_ctx;

	lockdep_assert_held(&ctx->lock);

	if (parent_ctx)
1210
		ctx->parent_ctx = NULL;
1211
	ctx->generation++;
1212 1213

	return parent_ctx;
1214 1215
}

1216 1217 1218 1219 1220 1221 1222 1223 1224 1225 1226 1227 1228 1229 1230 1231 1232 1233 1234 1235 1236 1237
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);
}

1238
/*
1239
 * If we inherit events we want to return the parent event id
1240 1241
 * to userspace.
 */
1242
static u64 primary_event_id(struct perf_event *event)
1243
{
1244
	u64 id = event->id;
1245

1246 1247
	if (event->parent)
		id = event->parent->id;
1248 1249 1250 1251

	return id;
}

1252
/*
1253
 * Get the perf_event_context for a task and lock it.
1254
 *
1255 1256 1257
 * This has to cope with with the fact that until it is locked,
 * the context could get moved to another task.
 */
1258
static struct perf_event_context *
P
Peter Zijlstra 已提交
1259
perf_lock_task_context(struct task_struct *task, int ctxn, unsigned long *flags)
1260
{
1261
	struct perf_event_context *ctx;
1262

P
Peter Zijlstra 已提交
1263
retry:
1264 1265 1266
	/*
	 * One of the few rules of preemptible RCU is that one cannot do
	 * rcu_read_unlock() while holding a scheduler (or nested) lock when
1267
	 * part of the read side critical section was irqs-enabled -- see
1268 1269 1270
	 * rcu_read_unlock_special().
	 *
	 * Since ctx->lock nests under rq->lock we must ensure the entire read
1271
	 * side critical section has interrupts disabled.
1272
	 */
1273
	local_irq_save(*flags);
1274
	rcu_read_lock();
P
Peter Zijlstra 已提交
1275
	ctx = rcu_dereference(task->perf_event_ctxp[ctxn]);
1276 1277 1278 1279
	if (ctx) {
		/*
		 * If this context is a clone of another, it might
		 * get swapped for another underneath us by
1280
		 * perf_event_task_sched_out, though the
1281 1282 1283 1284 1285 1286
		 * 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.
		 */
1287
		raw_spin_lock(&ctx->lock);
P
Peter Zijlstra 已提交
1288
		if (ctx != rcu_dereference(task->perf_event_ctxp[ctxn])) {
1289
			raw_spin_unlock(&ctx->lock);
1290
			rcu_read_unlock();
1291
			local_irq_restore(*flags);
1292 1293
			goto retry;
		}
1294

1295 1296
		if (ctx->task == TASK_TOMBSTONE ||
		    !atomic_inc_not_zero(&ctx->refcount)) {
1297
			raw_spin_unlock(&ctx->lock);
1298
			ctx = NULL;
P
Peter Zijlstra 已提交
1299 1300
		} else {
			WARN_ON_ONCE(ctx->task != task);
1301
		}
1302 1303
	}
	rcu_read_unlock();
1304 1305
	if (!ctx)
		local_irq_restore(*flags);
1306 1307 1308 1309 1310 1311 1312 1313
	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
1314 1315
static struct perf_event_context *
perf_pin_task_context(struct task_struct *task, int ctxn)
1316
{
1317
	struct perf_event_context *ctx;
1318 1319
	unsigned long flags;

P
Peter Zijlstra 已提交
1320
	ctx = perf_lock_task_context(task, ctxn, &flags);
1321 1322
	if (ctx) {
		++ctx->pin_count;
1323
		raw_spin_unlock_irqrestore(&ctx->lock, flags);
1324 1325 1326 1327
	}
	return ctx;
}

1328
static void perf_unpin_context(struct perf_event_context *ctx)
1329 1330 1331
{
	unsigned long flags;

1332
	raw_spin_lock_irqsave(&ctx->lock, flags);
1333
	--ctx->pin_count;
1334
	raw_spin_unlock_irqrestore(&ctx->lock, flags);
1335 1336
}

1337 1338 1339 1340 1341 1342 1343 1344 1345 1346 1347
/*
 * 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;
}

1348 1349 1350
static u64 perf_event_time(struct perf_event *event)
{
	struct perf_event_context *ctx = event->ctx;
S
Stephane Eranian 已提交
1351 1352 1353 1354

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

1355 1356 1357
	return ctx ? ctx->time : 0;
}

1358 1359 1360 1361 1362 1363 1364 1365
/*
 * 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;

1366 1367
	lockdep_assert_held(&ctx->lock);

1368 1369 1370
	if (event->state < PERF_EVENT_STATE_INACTIVE ||
	    event->group_leader->state < PERF_EVENT_STATE_INACTIVE)
		return;
1371

S
Stephane Eranian 已提交
1372 1373 1374 1375 1376 1377 1378 1379 1380 1381 1382
	/*
	 * 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))
1383
		run_end = perf_cgroup_event_time(event);
S
Stephane Eranian 已提交
1384 1385
	else if (ctx->is_active)
		run_end = ctx->time;
1386 1387 1388 1389
	else
		run_end = event->tstamp_stopped;

	event->total_time_enabled = run_end - event->tstamp_enabled;
1390 1391 1392 1393

	if (event->state == PERF_EVENT_STATE_INACTIVE)
		run_end = event->tstamp_stopped;
	else
1394
		run_end = perf_event_time(event);
1395 1396

	event->total_time_running = run_end - event->tstamp_running;
S
Stephane Eranian 已提交
1397

1398 1399
}

1400 1401 1402 1403 1404 1405 1406 1407 1408 1409 1410 1411
/*
 * 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);
}

1412 1413 1414 1415 1416 1417 1418 1419 1420
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;
}

1421
/*
1422
 * Add a event from the lists for its context.
1423 1424
 * Must be called with ctx->mutex and ctx->lock held.
 */
1425
static void
1426
list_add_event(struct perf_event *event, struct perf_event_context *ctx)
1427
{
1428

P
Peter Zijlstra 已提交
1429 1430
	lockdep_assert_held(&ctx->lock);

1431 1432
	WARN_ON_ONCE(event->attach_state & PERF_ATTACH_CONTEXT);
	event->attach_state |= PERF_ATTACH_CONTEXT;
1433 1434

	/*
1435 1436 1437
	 * 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.
1438
	 */
1439
	if (event->group_leader == event) {
1440 1441
		struct list_head *list;

1442 1443 1444
		if (is_software_event(event))
			event->group_flags |= PERF_GROUP_SOFTWARE;

1445 1446
		list = ctx_group_list(event, ctx);
		list_add_tail(&event->group_entry, list);
P
Peter Zijlstra 已提交
1447
	}
P
Peter Zijlstra 已提交
1448

1449
	list_update_cgroup_event(event, ctx, true);
S
Stephane Eranian 已提交
1450

1451 1452 1453
	list_add_rcu(&event->event_entry, &ctx->event_list);
	ctx->nr_events++;
	if (event->attr.inherit_stat)
1454
		ctx->nr_stat++;
1455 1456

	ctx->generation++;
1457 1458
}

J
Jiri Olsa 已提交
1459 1460 1461 1462 1463 1464 1465 1466 1467
/*
 * 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
1468
static void __perf_event_read_size(struct perf_event *event, int nr_siblings)
1469 1470 1471 1472 1473 1474 1475 1476 1477 1478 1479 1480 1481 1482 1483
{
	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
1484
		nr += nr_siblings;
1485 1486 1487 1488 1489 1490 1491
		size += sizeof(u64);
	}

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

P
Peter Zijlstra 已提交
1492
static void __perf_event_header_size(struct perf_event *event, u64 sample_type)
1493 1494 1495 1496 1497 1498 1499
{
	struct perf_sample_data *data;
	u16 size = 0;

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

1500 1501 1502 1503 1504 1505
	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
1506 1507 1508
	if (sample_type & PERF_SAMPLE_WEIGHT)
		size += sizeof(data->weight);

1509 1510 1511
	if (sample_type & PERF_SAMPLE_READ)
		size += event->read_size;

1512 1513 1514
	if (sample_type & PERF_SAMPLE_DATA_SRC)
		size += sizeof(data->data_src.val);

A
Andi Kleen 已提交
1515 1516 1517
	if (sample_type & PERF_SAMPLE_TRANSACTION)
		size += sizeof(data->txn);

1518 1519 1520
	event->header_size = size;
}

P
Peter Zijlstra 已提交
1521 1522 1523 1524 1525 1526 1527 1528 1529 1530 1531
/*
 * 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);
}

1532 1533 1534 1535 1536 1537
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;

1538 1539 1540 1541 1542 1543
	if (sample_type & PERF_SAMPLE_TID)
		size += sizeof(data->tid_entry);

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

1544 1545 1546
	if (sample_type & PERF_SAMPLE_IDENTIFIER)
		size += sizeof(data->id);

1547 1548 1549 1550 1551 1552 1553 1554 1555
	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);

1556
	event->id_header_size = size;
1557 1558
}

P
Peter Zijlstra 已提交
1559 1560 1561 1562 1563 1564 1565 1566 1567 1568 1569 1570 1571 1572 1573 1574 1575 1576 1577 1578 1579
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;
}

1580 1581
static void perf_group_attach(struct perf_event *event)
{
1582
	struct perf_event *group_leader = event->group_leader, *pos;
1583

P
Peter Zijlstra 已提交
1584 1585 1586 1587 1588 1589
	/*
	 * We can have double attach due to group movement in perf_event_open.
	 */
	if (event->attach_state & PERF_ATTACH_GROUP)
		return;

1590 1591 1592 1593 1594
	event->attach_state |= PERF_ATTACH_GROUP;

	if (group_leader == event)
		return;

P
Peter Zijlstra 已提交
1595 1596
	WARN_ON_ONCE(group_leader->ctx != event->ctx);

1597 1598 1599 1600 1601 1602
	if (group_leader->group_flags & PERF_GROUP_SOFTWARE &&
			!is_software_event(event))
		group_leader->group_flags &= ~PERF_GROUP_SOFTWARE;

	list_add_tail(&event->group_entry, &group_leader->sibling_list);
	group_leader->nr_siblings++;
1603 1604 1605 1606 1607

	perf_event__header_size(group_leader);

	list_for_each_entry(pos, &group_leader->sibling_list, group_entry)
		perf_event__header_size(pos);
1608 1609
}

1610
/*
1611
 * Remove a event from the lists for its context.
1612
 * Must be called with ctx->mutex and ctx->lock held.
1613
 */
1614
static void
1615
list_del_event(struct perf_event *event, struct perf_event_context *ctx)
1616
{
P
Peter Zijlstra 已提交
1617 1618 1619
	WARN_ON_ONCE(event->ctx != ctx);
	lockdep_assert_held(&ctx->lock);

1620 1621 1622 1623
	/*
	 * We can have double detach due to exit/hot-unplug + close.
	 */
	if (!(event->attach_state & PERF_ATTACH_CONTEXT))
1624
		return;
1625 1626 1627

	event->attach_state &= ~PERF_ATTACH_CONTEXT;

1628
	list_update_cgroup_event(event, ctx, false);
S
Stephane Eranian 已提交
1629

1630 1631
	ctx->nr_events--;
	if (event->attr.inherit_stat)
1632
		ctx->nr_stat--;
1633

1634
	list_del_rcu(&event->event_entry);
1635

1636 1637
	if (event->group_leader == event)
		list_del_init(&event->group_entry);
P
Peter Zijlstra 已提交
1638

1639
	update_group_times(event);
1640 1641 1642 1643 1644 1645 1646 1647 1648 1649

	/*
	 * 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;
1650 1651

	ctx->generation++;
1652 1653
}

1654
static void perf_group_detach(struct perf_event *event)
1655 1656
{
	struct perf_event *sibling, *tmp;
1657 1658 1659 1660 1661 1662 1663 1664 1665 1666 1667 1668 1669 1670 1671 1672
	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--;
1673
		goto out;
1674 1675 1676 1677
	}

	if (!list_empty(&event->group_entry))
		list = &event->group_entry;
1678

1679
	/*
1680 1681
	 * If this was a group event with sibling events then
	 * upgrade the siblings to singleton events by adding them
1682
	 * to whatever list we are on.
1683
	 */
1684
	list_for_each_entry_safe(sibling, tmp, &event->sibling_list, group_entry) {
1685 1686
		if (list)
			list_move_tail(&sibling->group_entry, list);
1687
		sibling->group_leader = sibling;
1688 1689 1690

		/* Inherit group flags from the previous leader */
		sibling->group_flags = event->group_flags;
P
Peter Zijlstra 已提交
1691 1692

		WARN_ON_ONCE(sibling->ctx != event->ctx);
1693
	}
1694 1695 1696 1697 1698 1699

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);
1700 1701
}

1702 1703
static bool is_orphaned_event(struct perf_event *event)
{
P
Peter Zijlstra 已提交
1704
	return event->state == PERF_EVENT_STATE_DEAD;
1705 1706
}

1707
static inline int __pmu_filter_match(struct perf_event *event)
1708 1709 1710 1711 1712
{
	struct pmu *pmu = event->pmu;
	return pmu->filter_match ? pmu->filter_match(event) : 1;
}

1713 1714 1715 1716 1717 1718 1719 1720 1721 1722 1723 1724 1725 1726 1727 1728 1729 1730 1731 1732 1733
/*
 * 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;
}

1734 1735 1736
static inline int
event_filter_match(struct perf_event *event)
{
1737 1738
	return (event->cpu == -1 || event->cpu == smp_processor_id()) &&
	       perf_cgroup_match(event) && pmu_filter_match(event);
1739 1740
}

1741 1742
static void
event_sched_out(struct perf_event *event,
1743
		  struct perf_cpu_context *cpuctx,
1744
		  struct perf_event_context *ctx)
1745
{
1746
	u64 tstamp = perf_event_time(event);
1747
	u64 delta;
P
Peter Zijlstra 已提交
1748 1749 1750 1751

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

1752 1753 1754 1755 1756 1757
	/*
	 * 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:
	 */
1758 1759
	if (event->state == PERF_EVENT_STATE_INACTIVE &&
	    !event_filter_match(event)) {
S
Stephane Eranian 已提交
1760
		delta = tstamp - event->tstamp_stopped;
1761
		event->tstamp_running += delta;
1762
		event->tstamp_stopped = tstamp;
1763 1764
	}

1765
	if (event->state != PERF_EVENT_STATE_ACTIVE)
1766
		return;
1767

1768 1769
	perf_pmu_disable(event->pmu);

1770 1771 1772
	event->tstamp_stopped = tstamp;
	event->pmu->del(event, 0);
	event->oncpu = -1;
1773 1774 1775 1776
	event->state = PERF_EVENT_STATE_INACTIVE;
	if (event->pending_disable) {
		event->pending_disable = 0;
		event->state = PERF_EVENT_STATE_OFF;
1777
	}
1778

1779
	if (!is_software_event(event))
1780
		cpuctx->active_oncpu--;
1781 1782
	if (!--ctx->nr_active)
		perf_event_ctx_deactivate(ctx);
1783 1784
	if (event->attr.freq && event->attr.sample_freq)
		ctx->nr_freq--;
1785
	if (event->attr.exclusive || !cpuctx->active_oncpu)
1786
		cpuctx->exclusive = 0;
1787 1788

	perf_pmu_enable(event->pmu);
1789 1790
}

1791
static void
1792
group_sched_out(struct perf_event *group_event,
1793
		struct perf_cpu_context *cpuctx,
1794
		struct perf_event_context *ctx)
1795
{
1796
	struct perf_event *event;
1797
	int state = group_event->state;
1798

1799 1800
	perf_pmu_disable(ctx->pmu);

1801
	event_sched_out(group_event, cpuctx, ctx);
1802 1803 1804 1805

	/*
	 * Schedule out siblings (if any):
	 */
1806 1807
	list_for_each_entry(event, &group_event->sibling_list, group_entry)
		event_sched_out(event, cpuctx, ctx);
1808

1809 1810
	perf_pmu_enable(ctx->pmu);

1811
	if (state == PERF_EVENT_STATE_ACTIVE && group_event->attr.exclusive)
1812 1813 1814
		cpuctx->exclusive = 0;
}

1815
#define DETACH_GROUP	0x01UL
1816

T
Thomas Gleixner 已提交
1817
/*
1818
 * Cross CPU call to remove a performance event
T
Thomas Gleixner 已提交
1819
 *
1820
 * We disable the event on the hardware level first. After that we
T
Thomas Gleixner 已提交
1821 1822
 * remove it from the context list.
 */
1823 1824 1825 1826 1827
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
1828
{
1829
	unsigned long flags = (unsigned long)info;
T
Thomas Gleixner 已提交
1830

1831
	event_sched_out(event, cpuctx, ctx);
1832
	if (flags & DETACH_GROUP)
1833
		perf_group_detach(event);
1834
	list_del_event(event, ctx);
1835 1836

	if (!ctx->nr_events && ctx->is_active) {
1837
		ctx->is_active = 0;
1838 1839 1840 1841
		if (ctx->task) {
			WARN_ON_ONCE(cpuctx->task_ctx != ctx);
			cpuctx->task_ctx = NULL;
		}
1842
	}
T
Thomas Gleixner 已提交
1843 1844 1845
}

/*
1846
 * Remove the event from a task's (or a CPU's) list of events.
T
Thomas Gleixner 已提交
1847
 *
1848 1849
 * If event->ctx is a cloned context, callers must make sure that
 * every task struct that event->ctx->task could possibly point to
1850 1851
 * 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.
1852
 * When called from perf_event_exit_task, it's OK because the
1853
 * context has been detached from its task.
T
Thomas Gleixner 已提交
1854
 */
1855
static void perf_remove_from_context(struct perf_event *event, unsigned long flags)
T
Thomas Gleixner 已提交
1856
{
1857
	lockdep_assert_held(&event->ctx->mutex);
T
Thomas Gleixner 已提交
1858

1859
	event_function_call(event, __perf_remove_from_context, (void *)flags);
T
Thomas Gleixner 已提交
1860 1861
}

1862
/*
1863
 * Cross CPU call to disable a performance event
1864
 */
1865 1866 1867 1868
static void __perf_event_disable(struct perf_event *event,
				 struct perf_cpu_context *cpuctx,
				 struct perf_event_context *ctx,
				 void *info)
1869
{
1870 1871
	if (event->state < PERF_EVENT_STATE_INACTIVE)
		return;
1872

1873 1874 1875 1876 1877 1878 1879 1880
	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;
1881 1882
}

1883
/*
1884
 * Disable a event.
1885
 *
1886 1887
 * If event->ctx is a cloned context, callers must make sure that
 * every task struct that event->ctx->task could possibly point to
1888
 * remains valid.  This condition is satisifed when called through
1889 1890
 * perf_event_for_each_child or perf_event_for_each because they
 * hold the top-level event's child_mutex, so any descendant that
1891 1892
 * goes to exit will block in perf_event_exit_event().
 *
1893
 * When called from perf_pending_event it's OK because event->ctx
1894
 * is the current context on this CPU and preemption is disabled,
1895
 * hence we can't get into perf_event_task_sched_out for this context.
1896
 */
P
Peter Zijlstra 已提交
1897
static void _perf_event_disable(struct perf_event *event)
1898
{
1899
	struct perf_event_context *ctx = event->ctx;
1900

1901
	raw_spin_lock_irq(&ctx->lock);
1902
	if (event->state <= PERF_EVENT_STATE_OFF) {
1903
		raw_spin_unlock_irq(&ctx->lock);
1904
		return;
1905
	}
1906
	raw_spin_unlock_irq(&ctx->lock);
1907

1908 1909 1910 1911 1912 1913
	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);
1914
}
P
Peter Zijlstra 已提交
1915 1916 1917 1918 1919 1920 1921 1922 1923 1924 1925 1926 1927

/*
 * 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);
}
1928
EXPORT_SYMBOL_GPL(perf_event_disable);
1929

S
Stephane Eranian 已提交
1930 1931 1932 1933 1934 1935 1936 1937 1938 1939 1940 1941 1942 1943 1944 1945 1946 1947 1948 1949 1950 1951 1952 1953 1954 1955 1956 1957 1958 1959 1960 1961 1962 1963 1964
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
1965 1966 1967
#define MAX_INTERRUPTS (~0ULL)

static void perf_log_throttle(struct perf_event *event, int enable);
1968
static void perf_log_itrace_start(struct perf_event *event);
P
Peter Zijlstra 已提交
1969

1970
static int
1971
event_sched_in(struct perf_event *event,
1972
		 struct perf_cpu_context *cpuctx,
1973
		 struct perf_event_context *ctx)
1974
{
1975
	u64 tstamp = perf_event_time(event);
1976
	int ret = 0;
1977

1978 1979
	lockdep_assert_held(&ctx->lock);

1980
	if (event->state <= PERF_EVENT_STATE_OFF)
1981 1982
		return 0;

1983 1984 1985 1986 1987 1988 1989
	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
1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000

	/*
	 * 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;
	}

2001 2002 2003 2004 2005
	/*
	 * The new state must be visible before we turn it on in the hardware:
	 */
	smp_wmb();

2006 2007
	perf_pmu_disable(event->pmu);

2008 2009
	perf_set_shadow_time(event, ctx, tstamp);

2010 2011
	perf_log_itrace_start(event);

P
Peter Zijlstra 已提交
2012
	if (event->pmu->add(event, PERF_EF_START)) {
2013 2014
		event->state = PERF_EVENT_STATE_INACTIVE;
		event->oncpu = -1;
2015 2016
		ret = -EAGAIN;
		goto out;
2017 2018
	}

2019 2020
	event->tstamp_running += tstamp - event->tstamp_stopped;

2021
	if (!is_software_event(event))
2022
		cpuctx->active_oncpu++;
2023 2024
	if (!ctx->nr_active++)
		perf_event_ctx_activate(ctx);
2025 2026
	if (event->attr.freq && event->attr.sample_freq)
		ctx->nr_freq++;
2027

2028
	if (event->attr.exclusive)
2029 2030
		cpuctx->exclusive = 1;

2031 2032 2033 2034
out:
	perf_pmu_enable(event->pmu);

	return ret;
2035 2036
}

2037
static int
2038
group_sched_in(struct perf_event *group_event,
2039
	       struct perf_cpu_context *cpuctx,
2040
	       struct perf_event_context *ctx)
2041
{
2042
	struct perf_event *event, *partial_group = NULL;
P
Peter Zijlstra 已提交
2043
	struct pmu *pmu = ctx->pmu;
2044 2045
	u64 now = ctx->time;
	bool simulate = false;
2046

2047
	if (group_event->state == PERF_EVENT_STATE_OFF)
2048 2049
		return 0;

2050
	pmu->start_txn(pmu, PERF_PMU_TXN_ADD);
2051

2052
	if (event_sched_in(group_event, cpuctx, ctx)) {
P
Peter Zijlstra 已提交
2053
		pmu->cancel_txn(pmu);
2054
		perf_mux_hrtimer_restart(cpuctx);
2055
		return -EAGAIN;
2056
	}
2057 2058 2059 2060

	/*
	 * Schedule in siblings as one group (if any):
	 */
2061
	list_for_each_entry(event, &group_event->sibling_list, group_entry) {
2062
		if (event_sched_in(event, cpuctx, ctx)) {
2063
			partial_group = event;
2064 2065 2066 2067
			goto group_error;
		}
	}

2068
	if (!pmu->commit_txn(pmu))
2069
		return 0;
2070

2071 2072 2073 2074
group_error:
	/*
	 * Groups can be scheduled in as one unit only, so undo any
	 * partial group before returning:
2075 2076 2077 2078 2079 2080 2081 2082 2083 2084
	 * 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.
2085
	 */
2086 2087
	list_for_each_entry(event, &group_event->sibling_list, group_entry) {
		if (event == partial_group)
2088 2089 2090 2091 2092 2093 2094 2095
			simulate = true;

		if (simulate) {
			event->tstamp_running += now - event->tstamp_stopped;
			event->tstamp_stopped = now;
		} else {
			event_sched_out(event, cpuctx, ctx);
		}
2096
	}
2097
	event_sched_out(group_event, cpuctx, ctx);
2098

P
Peter Zijlstra 已提交
2099
	pmu->cancel_txn(pmu);
2100

2101
	perf_mux_hrtimer_restart(cpuctx);
2102

2103 2104 2105
	return -EAGAIN;
}

2106
/*
2107
 * Work out whether we can put this event group on the CPU now.
2108
 */
2109
static int group_can_go_on(struct perf_event *event,
2110 2111 2112 2113
			   struct perf_cpu_context *cpuctx,
			   int can_add_hw)
{
	/*
2114
	 * Groups consisting entirely of software events can always go on.
2115
	 */
2116
	if (event->group_flags & PERF_GROUP_SOFTWARE)
2117 2118 2119
		return 1;
	/*
	 * If an exclusive group is already on, no other hardware
2120
	 * events can go on.
2121 2122 2123 2124 2125
	 */
	if (cpuctx->exclusive)
		return 0;
	/*
	 * If this group is exclusive and there are already
2126
	 * events on the CPU, it can't go on.
2127
	 */
2128
	if (event->attr.exclusive && cpuctx->active_oncpu)
2129 2130 2131 2132 2133 2134 2135 2136
		return 0;
	/*
	 * Otherwise, try to add it if all previous groups were able
	 * to go on.
	 */
	return can_add_hw;
}

2137 2138
static void add_event_to_ctx(struct perf_event *event,
			       struct perf_event_context *ctx)
2139
{
2140 2141
	u64 tstamp = perf_event_time(event);

2142
	list_add_event(event, ctx);
2143
	perf_group_attach(event);
2144 2145 2146
	event->tstamp_enabled = tstamp;
	event->tstamp_running = tstamp;
	event->tstamp_stopped = tstamp;
2147 2148
}

2149 2150 2151
static void ctx_sched_out(struct perf_event_context *ctx,
			  struct perf_cpu_context *cpuctx,
			  enum event_type_t event_type);
2152 2153 2154 2155 2156
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);
2157

2158 2159 2160 2161 2162 2163 2164 2165 2166 2167 2168 2169
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);
}

2170 2171 2172 2173 2174 2175 2176 2177 2178 2179 2180 2181
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);
}

2182 2183
static void ctx_resched(struct perf_cpu_context *cpuctx,
			struct perf_event_context *task_ctx)
2184
{
2185 2186 2187 2188 2189 2190
	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);
2191 2192
}

T
Thomas Gleixner 已提交
2193
/*
2194
 * Cross CPU call to install and enable a performance event
2195
 *
2196 2197
 * 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
2198
 */
2199
static int  __perf_install_in_context(void *info)
T
Thomas Gleixner 已提交
2200
{
2201 2202
	struct perf_event *event = info;
	struct perf_event_context *ctx = event->ctx;
P
Peter Zijlstra 已提交
2203
	struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
2204
	struct perf_event_context *task_ctx = cpuctx->task_ctx;
2205 2206
	bool activate = true;
	int ret = 0;
T
Thomas Gleixner 已提交
2207

2208
	raw_spin_lock(&cpuctx->ctx.lock);
2209
	if (ctx->task) {
2210 2211
		raw_spin_lock(&ctx->lock);
		task_ctx = ctx;
2212 2213 2214 2215

		/* If we're on the wrong CPU, try again */
		if (task_cpu(ctx->task) != smp_processor_id()) {
			ret = -ESRCH;
2216
			goto unlock;
2217
		}
2218

2219
		/*
2220 2221 2222
		 * 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.
2223
		 */
2224 2225 2226 2227 2228
		if (ctx->task != current)
			activate = false;
		else
			WARN_ON_ONCE(cpuctx->task_ctx && cpuctx->task_ctx != ctx);

2229 2230
	} else if (task_ctx) {
		raw_spin_lock(&task_ctx->lock);
2231
	}
2232

2233 2234 2235 2236 2237 2238 2239 2240
	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);
	}

2241
unlock:
2242
	perf_ctx_unlock(cpuctx, task_ctx);
2243

2244
	return ret;
T
Thomas Gleixner 已提交
2245 2246 2247
}

/*
2248 2249 2250
 * Attach a performance event to a context.
 *
 * Very similar to event_function_call, see comment there.
T
Thomas Gleixner 已提交
2251 2252
 */
static void
2253 2254
perf_install_in_context(struct perf_event_context *ctx,
			struct perf_event *event,
T
Thomas Gleixner 已提交
2255 2256
			int cpu)
{
2257
	struct task_struct *task = READ_ONCE(ctx->task);
2258

2259 2260
	lockdep_assert_held(&ctx->mutex);

2261 2262
	if (event->cpu != -1)
		event->cpu = cpu;
2263

2264 2265 2266 2267 2268 2269
	/*
	 * 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);

2270 2271 2272 2273 2274 2275 2276 2277 2278 2279 2280
	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;

2281 2282 2283 2284
	/*
	 * 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.
	 */
2285
again:
2286
	/*
2287 2288
	 * Cannot use task_function_call() because we need to run on the task's
	 * CPU regardless of whether its current or not.
2289
	 */
2290 2291 2292 2293 2294
	if (!cpu_function_call(task_cpu(task), __perf_install_in_context, event))
		return;

	raw_spin_lock_irq(&ctx->lock);
	task = ctx->task;
2295
	if (WARN_ON_ONCE(task == TASK_TOMBSTONE)) {
2296 2297 2298 2299 2300
		/*
		 * 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().
		 */
2301 2302 2303
		raw_spin_unlock_irq(&ctx->lock);
		return;
	}
2304 2305
	raw_spin_unlock_irq(&ctx->lock);
	/*
2306 2307
	 * Since !ctx->is_active doesn't mean anything, we must IPI
	 * unconditionally.
2308
	 */
2309
	goto again;
T
Thomas Gleixner 已提交
2310 2311
}

2312
/*
2313
 * Put a event into inactive state and update time fields.
2314 2315 2316 2317 2318 2319
 * 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.
 */
2320
static void __perf_event_mark_enabled(struct perf_event *event)
2321
{
2322
	struct perf_event *sub;
2323
	u64 tstamp = perf_event_time(event);
2324

2325
	event->state = PERF_EVENT_STATE_INACTIVE;
2326
	event->tstamp_enabled = tstamp - event->total_time_enabled;
P
Peter Zijlstra 已提交
2327
	list_for_each_entry(sub, &event->sibling_list, group_entry) {
2328 2329
		if (sub->state >= PERF_EVENT_STATE_INACTIVE)
			sub->tstamp_enabled = tstamp - sub->total_time_enabled;
P
Peter Zijlstra 已提交
2330
	}
2331 2332
}

2333
/*
2334
 * Cross CPU call to enable a performance event
2335
 */
2336 2337 2338 2339
static void __perf_event_enable(struct perf_event *event,
				struct perf_cpu_context *cpuctx,
				struct perf_event_context *ctx,
				void *info)
2340
{
2341
	struct perf_event *leader = event->group_leader;
2342
	struct perf_event_context *task_ctx;
2343

P
Peter Zijlstra 已提交
2344 2345
	if (event->state >= PERF_EVENT_STATE_INACTIVE ||
	    event->state <= PERF_EVENT_STATE_ERROR)
2346
		return;
2347

2348 2349 2350
	if (ctx->is_active)
		ctx_sched_out(ctx, cpuctx, EVENT_TIME);

2351
	__perf_event_mark_enabled(event);
2352

2353 2354 2355
	if (!ctx->is_active)
		return;

S
Stephane Eranian 已提交
2356
	if (!event_filter_match(event)) {
2357
		if (is_cgroup_event(event))
S
Stephane Eranian 已提交
2358
			perf_cgroup_defer_enabled(event);
2359
		ctx_sched_in(ctx, cpuctx, EVENT_TIME, current);
2360
		return;
S
Stephane Eranian 已提交
2361
	}
2362

2363
	/*
2364
	 * If the event is in a group and isn't the group leader,
2365
	 * then don't put it on unless the group is on.
2366
	 */
2367 2368
	if (leader != event && leader->state != PERF_EVENT_STATE_ACTIVE) {
		ctx_sched_in(ctx, cpuctx, EVENT_TIME, current);
2369
		return;
2370
	}
2371

2372 2373 2374
	task_ctx = cpuctx->task_ctx;
	if (ctx->task)
		WARN_ON_ONCE(task_ctx != ctx);
2375

2376
	ctx_resched(cpuctx, task_ctx);
2377 2378
}

2379
/*
2380
 * Enable a event.
2381
 *
2382 2383
 * If event->ctx is a cloned context, callers must make sure that
 * every task struct that event->ctx->task could possibly point to
2384
 * remains valid.  This condition is satisfied when called through
2385 2386
 * perf_event_for_each_child or perf_event_for_each as described
 * for perf_event_disable.
2387
 */
P
Peter Zijlstra 已提交
2388
static void _perf_event_enable(struct perf_event *event)
2389
{
2390
	struct perf_event_context *ctx = event->ctx;
2391

2392
	raw_spin_lock_irq(&ctx->lock);
P
Peter Zijlstra 已提交
2393 2394
	if (event->state >= PERF_EVENT_STATE_INACTIVE ||
	    event->state <  PERF_EVENT_STATE_ERROR) {
2395
		raw_spin_unlock_irq(&ctx->lock);
2396 2397 2398 2399
		return;
	}

	/*
2400
	 * If the event is in error state, clear that first.
2401 2402 2403 2404
	 *
	 * 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.
2405
	 */
2406 2407
	if (event->state == PERF_EVENT_STATE_ERROR)
		event->state = PERF_EVENT_STATE_OFF;
2408
	raw_spin_unlock_irq(&ctx->lock);
2409

2410
	event_function_call(event, __perf_event_enable, NULL);
2411
}
P
Peter Zijlstra 已提交
2412 2413 2414 2415 2416 2417 2418 2419 2420 2421 2422 2423

/*
 * 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);
}
2424
EXPORT_SYMBOL_GPL(perf_event_enable);
2425

2426 2427 2428 2429 2430
struct stop_event_data {
	struct perf_event	*event;
	unsigned int		restart;
};

2431 2432
static int __perf_event_stop(void *info)
{
2433 2434
	struct stop_event_data *sd = info;
	struct perf_event *event = sd->event;
2435

2436
	/* if it's already INACTIVE, do nothing */
2437 2438 2439 2440 2441 2442 2443 2444 2445 2446 2447 2448 2449 2450 2451
	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);

2452 2453 2454 2455 2456 2457 2458 2459 2460 2461 2462 2463
	/*
	 * 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);

2464 2465 2466
	return 0;
}

2467 2468 2469 2470 2471 2472 2473 2474 2475 2476 2477 2478 2479 2480 2481 2482 2483 2484 2485 2486 2487 2488 2489 2490 2491 2492 2493 2494 2495 2496 2497 2498 2499 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
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
2532
static int _perf_event_refresh(struct perf_event *event, int refresh)
2533
{
2534
	/*
2535
	 * not supported on inherited events
2536
	 */
2537
	if (event->attr.inherit || !is_sampling_event(event))
2538 2539
		return -EINVAL;

2540
	atomic_add(refresh, &event->event_limit);
P
Peter Zijlstra 已提交
2541
	_perf_event_enable(event);
2542 2543

	return 0;
2544
}
P
Peter Zijlstra 已提交
2545 2546 2547 2548 2549 2550 2551 2552 2553 2554 2555 2556 2557 2558 2559

/*
 * 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;
}
2560
EXPORT_SYMBOL_GPL(perf_event_refresh);
2561

2562 2563 2564
static void ctx_sched_out(struct perf_event_context *ctx,
			  struct perf_cpu_context *cpuctx,
			  enum event_type_t event_type)
2565
{
2566
	int is_active = ctx->is_active;
P
Peter Zijlstra 已提交
2567
	struct perf_event *event;
2568

P
Peter Zijlstra 已提交
2569
	lockdep_assert_held(&ctx->lock);
2570

2571 2572 2573 2574 2575 2576 2577
	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);
2578
		return;
2579 2580
	}

2581
	ctx->is_active &= ~event_type;
2582 2583 2584
	if (!(ctx->is_active & EVENT_ALL))
		ctx->is_active = 0;

2585 2586 2587 2588 2589
	if (ctx->task) {
		WARN_ON_ONCE(cpuctx->task_ctx != ctx);
		if (!ctx->is_active)
			cpuctx->task_ctx = NULL;
	}
2590

2591 2592 2593 2594 2595 2596 2597 2598 2599 2600
	/*
	 * 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.
	 */
2601 2602 2603 2604 2605 2606
	if (is_active & EVENT_TIME) {
		/* update (and stop) ctx time */
		update_context_time(ctx);
		update_cgrp_time_from_cpuctx(cpuctx);
	}

2607 2608
	is_active ^= ctx->is_active; /* changed bits */

2609
	if (!ctx->nr_active || !(is_active & EVENT_ALL))
2610
		return;
2611

P
Peter Zijlstra 已提交
2612
	perf_pmu_disable(ctx->pmu);
2613
	if (is_active & EVENT_PINNED) {
2614 2615
		list_for_each_entry(event, &ctx->pinned_groups, group_entry)
			group_sched_out(event, cpuctx, ctx);
P
Peter Zijlstra 已提交
2616
	}
2617

2618
	if (is_active & EVENT_FLEXIBLE) {
2619
		list_for_each_entry(event, &ctx->flexible_groups, group_entry)
2620
			group_sched_out(event, cpuctx, ctx);
P
Peter Zijlstra 已提交
2621
	}
P
Peter Zijlstra 已提交
2622
	perf_pmu_enable(ctx->pmu);
2623 2624
}

2625
/*
2626 2627 2628 2629 2630 2631
 * 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().
2632
 */
2633 2634
static int context_equiv(struct perf_event_context *ctx1,
			 struct perf_event_context *ctx2)
2635
{
2636 2637 2638
	lockdep_assert_held(&ctx1->lock);
	lockdep_assert_held(&ctx2->lock);

2639 2640 2641 2642 2643 2644 2645 2646 2647 2648 2649 2650 2651 2652 2653 2654 2655 2656 2657 2658 2659 2660
	/* 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;
2661 2662
}

2663 2664
static void __perf_event_sync_stat(struct perf_event *event,
				     struct perf_event *next_event)
2665 2666 2667
{
	u64 value;

2668
	if (!event->attr.inherit_stat)
2669 2670 2671
		return;

	/*
2672
	 * Update the event value, we cannot use perf_event_read()
2673 2674
	 * because we're in the middle of a context switch and have IRQs
	 * disabled, which upsets smp_call_function_single(), however
2675
	 * we know the event must be on the current CPU, therefore we
2676 2677
	 * don't need to use it.
	 */
2678 2679
	switch (event->state) {
	case PERF_EVENT_STATE_ACTIVE:
2680 2681
		event->pmu->read(event);
		/* fall-through */
2682

2683 2684
	case PERF_EVENT_STATE_INACTIVE:
		update_event_times(event);
2685 2686 2687 2688 2689 2690 2691
		break;

	default:
		break;
	}

	/*
2692
	 * In order to keep per-task stats reliable we need to flip the event
2693 2694
	 * values when we flip the contexts.
	 */
2695 2696 2697
	value = local64_read(&next_event->count);
	value = local64_xchg(&event->count, value);
	local64_set(&next_event->count, value);
2698

2699 2700
	swap(event->total_time_enabled, next_event->total_time_enabled);
	swap(event->total_time_running, next_event->total_time_running);
2701

2702
	/*
2703
	 * Since we swizzled the values, update the user visible data too.
2704
	 */
2705 2706
	perf_event_update_userpage(event);
	perf_event_update_userpage(next_event);
2707 2708
}

2709 2710
static void perf_event_sync_stat(struct perf_event_context *ctx,
				   struct perf_event_context *next_ctx)
2711
{
2712
	struct perf_event *event, *next_event;
2713 2714 2715 2716

	if (!ctx->nr_stat)
		return;

2717 2718
	update_context_time(ctx);

2719 2720
	event = list_first_entry(&ctx->event_list,
				   struct perf_event, event_entry);
2721

2722 2723
	next_event = list_first_entry(&next_ctx->event_list,
					struct perf_event, event_entry);
2724

2725 2726
	while (&event->event_entry != &ctx->event_list &&
	       &next_event->event_entry != &next_ctx->event_list) {
2727

2728
		__perf_event_sync_stat(event, next_event);
2729

2730 2731
		event = list_next_entry(event, event_entry);
		next_event = list_next_entry(next_event, event_entry);
2732 2733 2734
	}
}

2735 2736
static void perf_event_context_sched_out(struct task_struct *task, int ctxn,
					 struct task_struct *next)
T
Thomas Gleixner 已提交
2737
{
P
Peter Zijlstra 已提交
2738
	struct perf_event_context *ctx = task->perf_event_ctxp[ctxn];
2739
	struct perf_event_context *next_ctx;
2740
	struct perf_event_context *parent, *next_parent;
P
Peter Zijlstra 已提交
2741
	struct perf_cpu_context *cpuctx;
2742
	int do_switch = 1;
T
Thomas Gleixner 已提交
2743

P
Peter Zijlstra 已提交
2744 2745
	if (likely(!ctx))
		return;
2746

P
Peter Zijlstra 已提交
2747 2748
	cpuctx = __get_cpu_context(ctx);
	if (!cpuctx->task_ctx)
T
Thomas Gleixner 已提交
2749 2750
		return;

2751
	rcu_read_lock();
P
Peter Zijlstra 已提交
2752
	next_ctx = next->perf_event_ctxp[ctxn];
2753 2754 2755 2756 2757 2758 2759
	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. */
2760
	if (!parent && !next_parent)
2761 2762 2763
		goto unlock;

	if (next_parent == ctx || next_ctx == parent || next_parent == parent) {
2764 2765 2766 2767 2768 2769 2770 2771 2772
		/*
		 * 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.
		 */
2773 2774
		raw_spin_lock(&ctx->lock);
		raw_spin_lock_nested(&next_ctx->lock, SINGLE_DEPTH_NESTING);
2775
		if (context_equiv(ctx, next_ctx)) {
2776 2777
			WRITE_ONCE(ctx->task, next);
			WRITE_ONCE(next_ctx->task, task);
2778 2779 2780

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

2781 2782 2783 2784 2785 2786 2787 2788 2789 2790
			/*
			 * 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);

2791
			do_switch = 0;
2792

2793
			perf_event_sync_stat(ctx, next_ctx);
2794
		}
2795 2796
		raw_spin_unlock(&next_ctx->lock);
		raw_spin_unlock(&ctx->lock);
2797
	}
2798
unlock:
2799
	rcu_read_unlock();
2800

2801
	if (do_switch) {
2802
		raw_spin_lock(&ctx->lock);
P
Peter Zijlstra 已提交
2803
		task_ctx_sched_out(cpuctx, ctx);
2804
		raw_spin_unlock(&ctx->lock);
2805
	}
T
Thomas Gleixner 已提交
2806 2807
}

2808 2809 2810 2811 2812 2813 2814 2815 2816 2817 2818 2819 2820 2821 2822 2823 2824 2825 2826 2827 2828 2829 2830 2831 2832 2833 2834 2835 2836 2837 2838 2839 2840 2841 2842 2843 2844 2845 2846 2847 2848 2849 2850 2851 2852 2853 2854 2855 2856 2857
void perf_sched_cb_dec(struct pmu *pmu)
{
	this_cpu_dec(perf_sched_cb_usages);
}

void perf_sched_cb_inc(struct pmu *pmu)
{
	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.
 */
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;
	unsigned long flags;

	if (prev == next)
		return;

	local_irq_save(flags);

	rcu_read_lock();

	list_for_each_entry_rcu(pmu, &pmus, entry) {
		if (pmu->sched_task) {
			cpuctx = this_cpu_ptr(pmu->pmu_cpu_context);

			perf_ctx_lock(cpuctx, cpuctx->task_ctx);

			perf_pmu_disable(pmu);

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

			perf_pmu_enable(pmu);

			perf_ctx_unlock(cpuctx, cpuctx->task_ctx);
		}
	}

	rcu_read_unlock();

	local_irq_restore(flags);
}

2858 2859 2860
static void perf_event_switch(struct task_struct *task,
			      struct task_struct *next_prev, bool sched_in);

P
Peter Zijlstra 已提交
2861 2862 2863 2864 2865 2866 2867 2868 2869 2870 2871 2872 2873 2874
#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.
 */
2875 2876
void __perf_event_task_sched_out(struct task_struct *task,
				 struct task_struct *next)
P
Peter Zijlstra 已提交
2877 2878 2879
{
	int ctxn;

2880 2881 2882
	if (__this_cpu_read(perf_sched_cb_usages))
		perf_pmu_sched_task(task, next, false);

2883 2884 2885
	if (atomic_read(&nr_switch_events))
		perf_event_switch(task, next, false);

P
Peter Zijlstra 已提交
2886 2887
	for_each_task_context_nr(ctxn)
		perf_event_context_sched_out(task, ctxn, next);
S
Stephane Eranian 已提交
2888 2889 2890 2891 2892 2893

	/*
	 * 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
	 */
2894
	if (atomic_read(this_cpu_ptr(&perf_cgroup_events)))
2895
		perf_cgroup_sched_out(task, next);
P
Peter Zijlstra 已提交
2896 2897
}

2898 2899 2900 2901 2902 2903 2904
/*
 * 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);
2905 2906
}

2907
static void
2908
ctx_pinned_sched_in(struct perf_event_context *ctx,
2909
		    struct perf_cpu_context *cpuctx)
T
Thomas Gleixner 已提交
2910
{
2911
	struct perf_event *event;
T
Thomas Gleixner 已提交
2912

2913 2914
	list_for_each_entry(event, &ctx->pinned_groups, group_entry) {
		if (event->state <= PERF_EVENT_STATE_OFF)
2915
			continue;
2916
		if (!event_filter_match(event))
2917 2918
			continue;

S
Stephane Eranian 已提交
2919 2920 2921 2922
		/* may need to reset tstamp_enabled */
		if (is_cgroup_event(event))
			perf_cgroup_mark_enabled(event, ctx);

2923
		if (group_can_go_on(event, cpuctx, 1))
2924
			group_sched_in(event, cpuctx, ctx);
2925 2926 2927 2928 2929

		/*
		 * If this pinned group hasn't been scheduled,
		 * put it in error state.
		 */
2930 2931 2932
		if (event->state == PERF_EVENT_STATE_INACTIVE) {
			update_group_times(event);
			event->state = PERF_EVENT_STATE_ERROR;
2933
		}
2934
	}
2935 2936 2937 2938
}

static void
ctx_flexible_sched_in(struct perf_event_context *ctx,
2939
		      struct perf_cpu_context *cpuctx)
2940 2941 2942
{
	struct perf_event *event;
	int can_add_hw = 1;
2943

2944 2945 2946
	list_for_each_entry(event, &ctx->flexible_groups, group_entry) {
		/* Ignore events in OFF or ERROR state */
		if (event->state <= PERF_EVENT_STATE_OFF)
2947
			continue;
2948 2949
		/*
		 * Listen to the 'cpu' scheduling filter constraint
2950
		 * of events:
2951
		 */
2952
		if (!event_filter_match(event))
T
Thomas Gleixner 已提交
2953 2954
			continue;

S
Stephane Eranian 已提交
2955 2956 2957 2958
		/* may need to reset tstamp_enabled */
		if (is_cgroup_event(event))
			perf_cgroup_mark_enabled(event, ctx);

P
Peter Zijlstra 已提交
2959
		if (group_can_go_on(event, cpuctx, can_add_hw)) {
2960
			if (group_sched_in(event, cpuctx, ctx))
2961
				can_add_hw = 0;
P
Peter Zijlstra 已提交
2962
		}
T
Thomas Gleixner 已提交
2963
	}
2964 2965 2966 2967 2968
}

static void
ctx_sched_in(struct perf_event_context *ctx,
	     struct perf_cpu_context *cpuctx,
S
Stephane Eranian 已提交
2969 2970
	     enum event_type_t event_type,
	     struct task_struct *task)
2971
{
2972
	int is_active = ctx->is_active;
P
Peter Zijlstra 已提交
2973 2974 2975
	u64 now;

	lockdep_assert_held(&ctx->lock);
S
Stephane Eranian 已提交
2976

2977
	if (likely(!ctx->nr_events))
2978
		return;
2979

2980
	ctx->is_active |= (event_type | EVENT_TIME);
2981 2982 2983 2984 2985 2986 2987
	if (ctx->task) {
		if (!is_active)
			cpuctx->task_ctx = ctx;
		else
			WARN_ON_ONCE(cpuctx->task_ctx != ctx);
	}

2988 2989 2990 2991 2992 2993 2994 2995 2996
	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);
	}

2997 2998 2999 3000
	/*
	 * First go through the list and put on any pinned groups
	 * in order to give them the best chance of going on.
	 */
3001
	if (is_active & EVENT_PINNED)
3002
		ctx_pinned_sched_in(ctx, cpuctx);
3003 3004

	/* Then walk through the lower prio flexible groups */
3005
	if (is_active & EVENT_FLEXIBLE)
3006
		ctx_flexible_sched_in(ctx, cpuctx);
3007 3008
}

3009
static void cpu_ctx_sched_in(struct perf_cpu_context *cpuctx,
S
Stephane Eranian 已提交
3010 3011
			     enum event_type_t event_type,
			     struct task_struct *task)
3012 3013 3014
{
	struct perf_event_context *ctx = &cpuctx->ctx;

S
Stephane Eranian 已提交
3015
	ctx_sched_in(ctx, cpuctx, event_type, task);
3016 3017
}

S
Stephane Eranian 已提交
3018 3019
static void perf_event_context_sched_in(struct perf_event_context *ctx,
					struct task_struct *task)
3020
{
P
Peter Zijlstra 已提交
3021
	struct perf_cpu_context *cpuctx;
3022

P
Peter Zijlstra 已提交
3023
	cpuctx = __get_cpu_context(ctx);
3024 3025 3026
	if (cpuctx->task_ctx == ctx)
		return;

3027
	perf_ctx_lock(cpuctx, ctx);
P
Peter Zijlstra 已提交
3028
	perf_pmu_disable(ctx->pmu);
3029 3030 3031 3032 3033 3034
	/*
	 * 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);
3035
	perf_event_sched_in(cpuctx, ctx, task);
3036 3037
	perf_pmu_enable(ctx->pmu);
	perf_ctx_unlock(cpuctx, ctx);
3038 3039
}

P
Peter Zijlstra 已提交
3040 3041 3042 3043 3044 3045 3046 3047 3048 3049 3050
/*
 * 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.
 */
3051 3052
void __perf_event_task_sched_in(struct task_struct *prev,
				struct task_struct *task)
P
Peter Zijlstra 已提交
3053 3054 3055 3056
{
	struct perf_event_context *ctx;
	int ctxn;

3057 3058 3059 3060 3061 3062 3063 3064 3065 3066
	/*
	 * 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
3067 3068 3069 3070 3071
	for_each_task_context_nr(ctxn) {
		ctx = task->perf_event_ctxp[ctxn];
		if (likely(!ctx))
			continue;

S
Stephane Eranian 已提交
3072
		perf_event_context_sched_in(ctx, task);
P
Peter Zijlstra 已提交
3073
	}
3074

3075 3076 3077
	if (atomic_read(&nr_switch_events))
		perf_event_switch(task, prev, true);

3078 3079
	if (__this_cpu_read(perf_sched_cb_usages))
		perf_pmu_sched_task(prev, task, true);
3080 3081
}

3082 3083 3084 3085 3086 3087 3088 3089 3090 3091 3092 3093 3094 3095 3096 3097 3098 3099 3100 3101 3102 3103 3104 3105 3106 3107 3108
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.
	 */
3109
#define REDUCE_FLS(a, b)		\
3110 3111 3112 3113 3114 3115 3116 3117 3118 3119 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
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;
	}

3149 3150 3151
	if (!divisor)
		return dividend;

3152 3153 3154
	return div64_u64(dividend, divisor);
}

3155 3156 3157
static DEFINE_PER_CPU(int, perf_throttled_count);
static DEFINE_PER_CPU(u64, perf_throttled_seq);

3158
static void perf_adjust_period(struct perf_event *event, u64 nsec, u64 count, bool disable)
3159
{
3160
	struct hw_perf_event *hwc = &event->hw;
3161
	s64 period, sample_period;
3162 3163
	s64 delta;

3164
	period = perf_calculate_period(event, nsec, count);
3165 3166 3167 3168 3169 3170 3171 3172 3173 3174

	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;
3175

3176
	if (local64_read(&hwc->period_left) > 8*sample_period) {
3177 3178 3179
		if (disable)
			event->pmu->stop(event, PERF_EF_UPDATE);

3180
		local64_set(&hwc->period_left, 0);
3181 3182 3183

		if (disable)
			event->pmu->start(event, PERF_EF_RELOAD);
3184
	}
3185 3186
}

3187 3188 3189 3190 3191 3192 3193
/*
 * 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)
3194
{
3195 3196
	struct perf_event *event;
	struct hw_perf_event *hwc;
3197
	u64 now, period = TICK_NSEC;
3198
	s64 delta;
3199

3200 3201 3202 3203 3204 3205
	/*
	 * 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))
3206 3207
		return;

3208
	raw_spin_lock(&ctx->lock);
3209
	perf_pmu_disable(ctx->pmu);
3210

3211
	list_for_each_entry_rcu(event, &ctx->event_list, event_entry) {
3212
		if (event->state != PERF_EVENT_STATE_ACTIVE)
3213 3214
			continue;

3215
		if (!event_filter_match(event))
3216 3217
			continue;

3218 3219
		perf_pmu_disable(event->pmu);

3220
		hwc = &event->hw;
3221

3222
		if (hwc->interrupts == MAX_INTERRUPTS) {
3223
			hwc->interrupts = 0;
3224
			perf_log_throttle(event, 1);
P
Peter Zijlstra 已提交
3225
			event->pmu->start(event, 0);
3226 3227
		}

3228
		if (!event->attr.freq || !event->attr.sample_freq)
3229
			goto next;
3230

3231 3232 3233 3234 3235
		/*
		 * stop the event and update event->count
		 */
		event->pmu->stop(event, PERF_EF_UPDATE);

3236
		now = local64_read(&event->count);
3237 3238
		delta = now - hwc->freq_count_stamp;
		hwc->freq_count_stamp = now;
3239

3240 3241 3242
		/*
		 * restart the event
		 * reload only if value has changed
3243 3244 3245
		 * we have stopped the event so tell that
		 * to perf_adjust_period() to avoid stopping it
		 * twice.
3246
		 */
3247
		if (delta > 0)
3248
			perf_adjust_period(event, period, delta, false);
3249 3250

		event->pmu->start(event, delta > 0 ? PERF_EF_RELOAD : 0);
3251 3252
	next:
		perf_pmu_enable(event->pmu);
3253
	}
3254

3255
	perf_pmu_enable(ctx->pmu);
3256
	raw_spin_unlock(&ctx->lock);
3257 3258
}

3259
/*
3260
 * Round-robin a context's events:
3261
 */
3262
static void rotate_ctx(struct perf_event_context *ctx)
T
Thomas Gleixner 已提交
3263
{
3264 3265 3266 3267 3268 3269
	/*
	 * 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);
3270 3271
}

3272
static int perf_rotate_context(struct perf_cpu_context *cpuctx)
3273
{
P
Peter Zijlstra 已提交
3274
	struct perf_event_context *ctx = NULL;
3275
	int rotate = 0;
3276

3277 3278 3279 3280
	if (cpuctx->ctx.nr_events) {
		if (cpuctx->ctx.nr_events != cpuctx->ctx.nr_active)
			rotate = 1;
	}
3281

P
Peter Zijlstra 已提交
3282
	ctx = cpuctx->task_ctx;
3283 3284 3285 3286
	if (ctx && ctx->nr_events) {
		if (ctx->nr_events != ctx->nr_active)
			rotate = 1;
	}
3287

3288
	if (!rotate)
3289 3290
		goto done;

3291
	perf_ctx_lock(cpuctx, cpuctx->task_ctx);
P
Peter Zijlstra 已提交
3292
	perf_pmu_disable(cpuctx->ctx.pmu);
3293

3294 3295 3296
	cpu_ctx_sched_out(cpuctx, EVENT_FLEXIBLE);
	if (ctx)
		ctx_sched_out(ctx, cpuctx, EVENT_FLEXIBLE);
T
Thomas Gleixner 已提交
3297

3298 3299 3300
	rotate_ctx(&cpuctx->ctx);
	if (ctx)
		rotate_ctx(ctx);
3301

3302
	perf_event_sched_in(cpuctx, ctx, current);
3303

3304 3305
	perf_pmu_enable(cpuctx->ctx.pmu);
	perf_ctx_unlock(cpuctx, cpuctx->task_ctx);
3306
done:
3307 3308

	return rotate;
3309 3310 3311 3312
}

void perf_event_task_tick(void)
{
3313 3314
	struct list_head *head = this_cpu_ptr(&active_ctx_list);
	struct perf_event_context *ctx, *tmp;
3315
	int throttled;
3316

3317 3318
	WARN_ON(!irqs_disabled());

3319 3320
	__this_cpu_inc(perf_throttled_seq);
	throttled = __this_cpu_xchg(perf_throttled_count, 0);
3321
	tick_dep_clear_cpu(smp_processor_id(), TICK_DEP_BIT_PERF_EVENTS);
3322

3323
	list_for_each_entry_safe(ctx, tmp, head, active_ctx_list)
3324
		perf_adjust_freq_unthr_context(ctx, throttled);
T
Thomas Gleixner 已提交
3325 3326
}

3327 3328 3329 3330 3331 3332 3333 3334 3335 3336
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;

3337
	__perf_event_mark_enabled(event);
3338 3339 3340 3341

	return 1;
}

3342
/*
3343
 * Enable all of a task's events that have been marked enable-on-exec.
3344 3345
 * This expects task == current.
 */
3346
static void perf_event_enable_on_exec(int ctxn)
3347
{
3348
	struct perf_event_context *ctx, *clone_ctx = NULL;
3349
	struct perf_cpu_context *cpuctx;
3350
	struct perf_event *event;
3351 3352 3353 3354
	unsigned long flags;
	int enabled = 0;

	local_irq_save(flags);
3355
	ctx = current->perf_event_ctxp[ctxn];
3356
	if (!ctx || !ctx->nr_events)
3357 3358
		goto out;

3359 3360
	cpuctx = __get_cpu_context(ctx);
	perf_ctx_lock(cpuctx, ctx);
3361
	ctx_sched_out(ctx, cpuctx, EVENT_TIME);
3362 3363
	list_for_each_entry(event, &ctx->event_list, event_entry)
		enabled |= event_enable_on_exec(event, ctx);
3364 3365

	/*
3366
	 * Unclone and reschedule this context if we enabled any event.
3367
	 */
3368
	if (enabled) {
3369
		clone_ctx = unclone_ctx(ctx);
3370 3371 3372
		ctx_resched(cpuctx, ctx);
	}
	perf_ctx_unlock(cpuctx, ctx);
3373

P
Peter Zijlstra 已提交
3374
out:
3375
	local_irq_restore(flags);
3376 3377 3378

	if (clone_ctx)
		put_ctx(clone_ctx);
3379 3380
}

3381 3382 3383
struct perf_read_data {
	struct perf_event *event;
	bool group;
3384
	int ret;
3385 3386
};

T
Thomas Gleixner 已提交
3387
/*
3388
 * Cross CPU call to read the hardware event
T
Thomas Gleixner 已提交
3389
 */
3390
static void __perf_event_read(void *info)
T
Thomas Gleixner 已提交
3391
{
3392 3393
	struct perf_read_data *data = info;
	struct perf_event *sub, *event = data->event;
3394
	struct perf_event_context *ctx = event->ctx;
P
Peter Zijlstra 已提交
3395
	struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
3396
	struct pmu *pmu = event->pmu;
I
Ingo Molnar 已提交
3397

3398 3399 3400 3401
	/*
	 * 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
3402 3403
	 * event->count would have been updated to a recent sample
	 * when the event was scheduled out.
3404 3405 3406 3407
	 */
	if (ctx->task && cpuctx->task_ctx != ctx)
		return;

3408
	raw_spin_lock(&ctx->lock);
S
Stephane Eranian 已提交
3409
	if (ctx->is_active) {
3410
		update_context_time(ctx);
S
Stephane Eranian 已提交
3411 3412
		update_cgrp_time_from_event(event);
	}
3413

3414
	update_event_times(event);
3415 3416
	if (event->state != PERF_EVENT_STATE_ACTIVE)
		goto unlock;
3417

3418 3419 3420
	if (!data->group) {
		pmu->read(event);
		data->ret = 0;
3421
		goto unlock;
3422 3423 3424 3425 3426
	}

	pmu->start_txn(pmu, PERF_PMU_TXN_READ);

	pmu->read(event);
3427 3428 3429

	list_for_each_entry(sub, &event->sibling_list, group_entry) {
		update_event_times(sub);
3430 3431 3432 3433 3434
		if (sub->state == PERF_EVENT_STATE_ACTIVE) {
			/*
			 * Use sibling's PMU rather than @event's since
			 * sibling could be on different (eg: software) PMU.
			 */
3435
			sub->pmu->read(sub);
3436
		}
3437
	}
3438 3439

	data->ret = pmu->commit_txn(pmu);
3440 3441

unlock:
3442
	raw_spin_unlock(&ctx->lock);
T
Thomas Gleixner 已提交
3443 3444
}

P
Peter Zijlstra 已提交
3445 3446
static inline u64 perf_event_count(struct perf_event *event)
{
3447 3448 3449 3450
	if (event->pmu->count)
		return event->pmu->count(event);

	return __perf_event_count(event);
P
Peter Zijlstra 已提交
3451 3452
}

3453 3454 3455 3456 3457 3458 3459 3460 3461 3462 3463 3464 3465 3466 3467 3468 3469 3470 3471 3472 3473 3474 3475 3476 3477 3478 3479 3480 3481 3482 3483 3484 3485 3486 3487 3488 3489 3490 3491 3492 3493 3494 3495 3496 3497 3498 3499 3500 3501 3502 3503 3504 3505
/*
 * 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;
}

3506
static int perf_event_read(struct perf_event *event, bool group)
T
Thomas Gleixner 已提交
3507
{
3508 3509
	int ret = 0;

T
Thomas Gleixner 已提交
3510
	/*
3511 3512
	 * If event is enabled and currently active on a CPU, update the
	 * value in the event structure:
T
Thomas Gleixner 已提交
3513
	 */
3514
	if (event->state == PERF_EVENT_STATE_ACTIVE) {
3515 3516 3517
		struct perf_read_data data = {
			.event = event,
			.group = group,
3518
			.ret = 0,
3519
		};
3520
		smp_call_function_single(event->oncpu,
3521
					 __perf_event_read, &data, 1);
3522
		ret = data.ret;
3523
	} else if (event->state == PERF_EVENT_STATE_INACTIVE) {
P
Peter Zijlstra 已提交
3524 3525 3526
		struct perf_event_context *ctx = event->ctx;
		unsigned long flags;

3527
		raw_spin_lock_irqsave(&ctx->lock, flags);
3528 3529 3530 3531 3532
		/*
		 * 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
3533
		if (ctx->is_active) {
3534
			update_context_time(ctx);
S
Stephane Eranian 已提交
3535 3536
			update_cgrp_time_from_event(event);
		}
3537 3538 3539 3540
		if (group)
			update_group_times(event);
		else
			update_event_times(event);
3541
		raw_spin_unlock_irqrestore(&ctx->lock, flags);
T
Thomas Gleixner 已提交
3542
	}
3543 3544

	return ret;
T
Thomas Gleixner 已提交
3545 3546
}

3547
/*
3548
 * Initialize the perf_event context in a task_struct:
3549
 */
3550
static void __perf_event_init_context(struct perf_event_context *ctx)
3551
{
3552
	raw_spin_lock_init(&ctx->lock);
3553
	mutex_init(&ctx->mutex);
3554
	INIT_LIST_HEAD(&ctx->active_ctx_list);
3555 3556
	INIT_LIST_HEAD(&ctx->pinned_groups);
	INIT_LIST_HEAD(&ctx->flexible_groups);
3557 3558
	INIT_LIST_HEAD(&ctx->event_list);
	atomic_set(&ctx->refcount, 1);
3559 3560 3561 3562 3563 3564 3565 3566 3567 3568 3569 3570 3571 3572 3573
}

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
3574
	}
3575 3576 3577
	ctx->pmu = pmu;

	return ctx;
3578 3579
}

3580 3581 3582 3583
static struct task_struct *
find_lively_task_by_vpid(pid_t vpid)
{
	struct task_struct *task;
T
Thomas Gleixner 已提交
3584 3585

	rcu_read_lock();
3586
	if (!vpid)
T
Thomas Gleixner 已提交
3587 3588
		task = current;
	else
3589
		task = find_task_by_vpid(vpid);
T
Thomas Gleixner 已提交
3590 3591 3592 3593 3594 3595 3596
	if (task)
		get_task_struct(task);
	rcu_read_unlock();

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

3597 3598 3599
	return task;
}

3600 3601 3602
/*
 * Returns a matching context with refcount and pincount.
 */
P
Peter Zijlstra 已提交
3603
static struct perf_event_context *
3604 3605
find_get_context(struct pmu *pmu, struct task_struct *task,
		struct perf_event *event)
T
Thomas Gleixner 已提交
3606
{
3607
	struct perf_event_context *ctx, *clone_ctx = NULL;
3608
	struct perf_cpu_context *cpuctx;
3609
	void *task_ctx_data = NULL;
3610
	unsigned long flags;
P
Peter Zijlstra 已提交
3611
	int ctxn, err;
3612
	int cpu = event->cpu;
T
Thomas Gleixner 已提交
3613

3614
	if (!task) {
3615
		/* Must be root to operate on a CPU event: */
3616
		if (perf_paranoid_cpu() && !capable(CAP_SYS_ADMIN))
T
Thomas Gleixner 已提交
3617 3618 3619
			return ERR_PTR(-EACCES);

		/*
3620
		 * We could be clever and allow to attach a event to an
T
Thomas Gleixner 已提交
3621 3622 3623
		 * offline CPU and activate it when the CPU comes up, but
		 * that's for later.
		 */
3624
		if (!cpu_online(cpu))
T
Thomas Gleixner 已提交
3625 3626
			return ERR_PTR(-ENODEV);

P
Peter Zijlstra 已提交
3627
		cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
T
Thomas Gleixner 已提交
3628
		ctx = &cpuctx->ctx;
3629
		get_ctx(ctx);
3630
		++ctx->pin_count;
T
Thomas Gleixner 已提交
3631 3632 3633 3634

		return ctx;
	}

P
Peter Zijlstra 已提交
3635 3636 3637 3638 3639
	err = -EINVAL;
	ctxn = pmu->task_ctx_nr;
	if (ctxn < 0)
		goto errout;

3640 3641 3642 3643 3644 3645 3646 3647
	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
3648
retry:
P
Peter Zijlstra 已提交
3649
	ctx = perf_lock_task_context(task, ctxn, &flags);
3650
	if (ctx) {
3651
		clone_ctx = unclone_ctx(ctx);
3652
		++ctx->pin_count;
3653 3654 3655 3656 3657

		if (task_ctx_data && !ctx->task_ctx_data) {
			ctx->task_ctx_data = task_ctx_data;
			task_ctx_data = NULL;
		}
3658
		raw_spin_unlock_irqrestore(&ctx->lock, flags);
3659 3660 3661

		if (clone_ctx)
			put_ctx(clone_ctx);
3662
	} else {
3663
		ctx = alloc_perf_context(pmu, task);
3664 3665 3666
		err = -ENOMEM;
		if (!ctx)
			goto errout;
3667

3668 3669 3670 3671 3672
		if (task_ctx_data) {
			ctx->task_ctx_data = task_ctx_data;
			task_ctx_data = NULL;
		}

3673 3674 3675 3676 3677 3678 3679 3680 3681 3682
		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;
3683
		else {
3684
			get_ctx(ctx);
3685
			++ctx->pin_count;
3686
			rcu_assign_pointer(task->perf_event_ctxp[ctxn], ctx);
3687
		}
3688 3689 3690
		mutex_unlock(&task->perf_event_mutex);

		if (unlikely(err)) {
3691
			put_ctx(ctx);
3692 3693 3694 3695

			if (err == -EAGAIN)
				goto retry;
			goto errout;
3696 3697 3698
		}
	}

3699
	kfree(task_ctx_data);
T
Thomas Gleixner 已提交
3700
	return ctx;
3701

P
Peter Zijlstra 已提交
3702
errout:
3703
	kfree(task_ctx_data);
3704
	return ERR_PTR(err);
T
Thomas Gleixner 已提交
3705 3706
}

L
Li Zefan 已提交
3707
static void perf_event_free_filter(struct perf_event *event);
3708
static void perf_event_free_bpf_prog(struct perf_event *event);
L
Li Zefan 已提交
3709

3710
static void free_event_rcu(struct rcu_head *head)
P
Peter Zijlstra 已提交
3711
{
3712
	struct perf_event *event;
P
Peter Zijlstra 已提交
3713

3714 3715 3716
	event = container_of(head, struct perf_event, rcu_head);
	if (event->ns)
		put_pid_ns(event->ns);
L
Li Zefan 已提交
3717
	perf_event_free_filter(event);
3718
	kfree(event);
P
Peter Zijlstra 已提交
3719 3720
}

3721 3722
static void ring_buffer_attach(struct perf_event *event,
			       struct ring_buffer *rb);
3723

3724 3725 3726 3727 3728 3729 3730 3731 3732
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);
}

3733
static bool is_sb_event(struct perf_event *event)
3734
{
3735 3736
	struct perf_event_attr *attr = &event->attr;

3737
	if (event->parent)
3738
		return false;
3739 3740

	if (event->attach_state & PERF_ATTACH_TASK)
3741
		return false;
3742

3743 3744 3745 3746 3747 3748 3749 3750 3751 3752 3753 3754
	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);
3755 3756
}

3757
static void unaccount_event_cpu(struct perf_event *event, int cpu)
3758
{
3759 3760 3761 3762 3763 3764
	if (event->parent)
		return;

	if (is_cgroup_event(event))
		atomic_dec(&per_cpu(perf_cgroup_events, cpu));
}
3765

3766 3767 3768 3769 3770 3771 3772 3773 3774 3775 3776 3777 3778 3779 3780 3781 3782 3783 3784 3785 3786 3787
#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);
}

3788 3789
static void unaccount_event(struct perf_event *event)
{
3790 3791
	bool dec = false;

3792 3793 3794 3795
	if (event->parent)
		return;

	if (event->attach_state & PERF_ATTACH_TASK)
3796
		dec = true;
3797 3798 3799 3800 3801 3802
	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);
3803
	if (event->attr.freq)
3804
		unaccount_freq_event();
3805
	if (event->attr.context_switch) {
3806
		dec = true;
3807 3808
		atomic_dec(&nr_switch_events);
	}
3809
	if (is_cgroup_event(event))
3810
		dec = true;
3811
	if (has_branch_stack(event))
3812 3813
		dec = true;

3814 3815 3816 3817
	if (dec) {
		if (!atomic_add_unless(&perf_sched_count, -1, 1))
			schedule_delayed_work(&perf_sched_work, HZ);
	}
3818 3819

	unaccount_event_cpu(event, event->cpu);
3820 3821

	unaccount_pmu_sb_event(event);
3822
}
3823

3824 3825 3826 3827 3828 3829 3830 3831
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);
}

3832 3833 3834 3835 3836 3837 3838 3839 3840 3841
/*
 * 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
3842
 * _free_event()), the latter -- before the first perf_install_in_context().
3843 3844 3845 3846 3847 3848 3849 3850 3851 3852 3853 3854 3855 3856 3857 3858 3859 3860 3861 3862 3863 3864 3865 3866 3867 3868 3869 3870 3871 3872 3873 3874 3875 3876 3877 3878 3879 3880 3881 3882 3883 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
 */
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;
}

3917 3918 3919
static void perf_addr_filters_splice(struct perf_event *event,
				       struct list_head *head);

P
Peter Zijlstra 已提交
3920
static void _free_event(struct perf_event *event)
3921
{
3922
	irq_work_sync(&event->pending);
3923

3924
	unaccount_event(event);
3925

3926
	if (event->rb) {
3927 3928 3929 3930 3931 3932 3933
		/*
		 * 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);
3934
		ring_buffer_attach(event, NULL);
3935
		mutex_unlock(&event->mmap_mutex);
3936 3937
	}

S
Stephane Eranian 已提交
3938 3939 3940
	if (is_cgroup_event(event))
		perf_detach_cgroup(event);

P
Peter Zijlstra 已提交
3941 3942 3943 3944 3945 3946
	if (!event->parent) {
		if (event->attr.sample_type & PERF_SAMPLE_CALLCHAIN)
			put_callchain_buffers();
	}

	perf_event_free_bpf_prog(event);
3947 3948
	perf_addr_filters_splice(event, NULL);
	kfree(event->addr_filters_offs);
P
Peter Zijlstra 已提交
3949 3950 3951 3952 3953 3954 3955

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

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

3956 3957
	exclusive_event_destroy(event);
	module_put(event->pmu->module);
P
Peter Zijlstra 已提交
3958 3959

	call_rcu(&event->rcu_head, free_event_rcu);
3960 3961
}

P
Peter Zijlstra 已提交
3962 3963 3964 3965 3966
/*
 * 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
3967
{
P
Peter Zijlstra 已提交
3968 3969 3970 3971 3972 3973
	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
3974

P
Peter Zijlstra 已提交
3975
	_free_event(event);
T
Thomas Gleixner 已提交
3976 3977
}

3978
/*
3979
 * Remove user event from the owner task.
3980
 */
3981
static void perf_remove_from_owner(struct perf_event *event)
3982
{
P
Peter Zijlstra 已提交
3983
	struct task_struct *owner;
3984

P
Peter Zijlstra 已提交
3985 3986
	rcu_read_lock();
	/*
3987 3988 3989
	 * 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
3990 3991
	 * owner->perf_event_mutex.
	 */
3992
	owner = lockless_dereference(event->owner);
P
Peter Zijlstra 已提交
3993 3994 3995 3996 3997 3998 3999 4000 4001 4002 4003
	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
4004 4005 4006 4007 4008 4009 4010 4011 4012 4013
		/*
		 * 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
4014 4015 4016 4017 4018 4019
		/*
		 * 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.
		 */
4020
		if (event->owner) {
P
Peter Zijlstra 已提交
4021
			list_del_init(&event->owner_entry);
4022 4023
			smp_store_release(&event->owner, NULL);
		}
P
Peter Zijlstra 已提交
4024 4025 4026
		mutex_unlock(&owner->perf_event_mutex);
		put_task_struct(owner);
	}
4027 4028 4029 4030 4031 4032 4033
}

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

4034 4035 4036 4037 4038 4039 4040 4041 4042 4043
	_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)
{
4044
	struct perf_event_context *ctx = event->ctx;
4045 4046
	struct perf_event *child, *tmp;

4047 4048 4049 4050 4051 4052 4053 4054 4055 4056
	/*
	 * 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;
	}

4057 4058
	if (!is_kernel_event(event))
		perf_remove_from_owner(event);
P
Peter Zijlstra 已提交
4059

4060
	ctx = perf_event_ctx_lock(event);
P
Peter Zijlstra 已提交
4061
	WARN_ON_ONCE(ctx->parent_ctx);
P
Peter Zijlstra 已提交
4062
	perf_remove_from_context(event, DETACH_GROUP);
P
Peter Zijlstra 已提交
4063

P
Peter Zijlstra 已提交
4064
	raw_spin_lock_irq(&ctx->lock);
P
Peter Zijlstra 已提交
4065
	/*
P
Peter Zijlstra 已提交
4066 4067
	 * Mark this even as STATE_DEAD, there is no external reference to it
	 * anymore.
P
Peter Zijlstra 已提交
4068
	 *
P
Peter Zijlstra 已提交
4069 4070 4071
	 * 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
4072
	 *
4073 4074
	 * Thus this guarantees that we will in fact observe and kill _ALL_
	 * child events.
P
Peter Zijlstra 已提交
4075
	 */
P
Peter Zijlstra 已提交
4076 4077 4078 4079
	event->state = PERF_EVENT_STATE_DEAD;
	raw_spin_unlock_irq(&ctx->lock);

	perf_event_ctx_unlock(event, ctx);
P
Peter Zijlstra 已提交
4080

4081 4082 4083
again:
	mutex_lock(&event->child_mutex);
	list_for_each_entry(child, &event->child_list, child_list) {
4084

4085 4086 4087 4088 4089 4090 4091 4092 4093 4094 4095 4096 4097 4098 4099 4100 4101 4102 4103 4104 4105 4106 4107 4108 4109 4110 4111 4112 4113 4114 4115 4116 4117 4118 4119 4120 4121 4122 4123 4124 4125 4126 4127 4128 4129 4130 4131 4132 4133
		/*
		 * 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);

4134 4135
no_ctx:
	put_event(event); /* Must be the 'last' reference */
P
Peter Zijlstra 已提交
4136 4137 4138 4139
	return 0;
}
EXPORT_SYMBOL_GPL(perf_event_release_kernel);

4140 4141 4142
/*
 * Called when the last reference to the file is gone.
 */
4143 4144
static int perf_release(struct inode *inode, struct file *file)
{
4145
	perf_event_release_kernel(file->private_data);
4146
	return 0;
4147 4148
}

4149
u64 perf_event_read_value(struct perf_event *event, u64 *enabled, u64 *running)
4150
{
4151
	struct perf_event *child;
4152 4153
	u64 total = 0;

4154 4155 4156
	*enabled = 0;
	*running = 0;

4157
	mutex_lock(&event->child_mutex);
4158

4159
	(void)perf_event_read(event, false);
4160 4161
	total += perf_event_count(event);

4162 4163 4164 4165 4166 4167
	*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) {
4168
		(void)perf_event_read(child, false);
4169
		total += perf_event_count(child);
4170 4171 4172
		*enabled += child->total_time_enabled;
		*running += child->total_time_running;
	}
4173
	mutex_unlock(&event->child_mutex);
4174 4175 4176

	return total;
}
4177
EXPORT_SYMBOL_GPL(perf_event_read_value);
4178

4179
static int __perf_read_group_add(struct perf_event *leader,
4180
					u64 read_format, u64 *values)
4181
{
4182 4183
	struct perf_event *sub;
	int n = 1; /* skip @nr */
4184
	int ret;
P
Peter Zijlstra 已提交
4185

4186 4187 4188
	ret = perf_event_read(leader, true);
	if (ret)
		return ret;
4189

4190 4191 4192 4193 4194 4195 4196 4197 4198
	/*
	 * 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);
	}
4199

4200 4201 4202 4203 4204 4205 4206 4207 4208
	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);
4209 4210
	if (read_format & PERF_FORMAT_ID)
		values[n++] = primary_event_id(leader);
4211

4212 4213 4214 4215 4216
	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);
	}
4217 4218

	return 0;
4219
}
4220

4221 4222 4223 4224 4225
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;
4226
	int ret;
4227
	u64 *values;
4228

4229
	lockdep_assert_held(&ctx->mutex);
4230

4231 4232 4233
	values = kzalloc(event->read_size, GFP_KERNEL);
	if (!values)
		return -ENOMEM;
4234

4235 4236 4237 4238 4239 4240 4241
	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);
4242

4243 4244 4245 4246 4247 4248 4249 4250 4251
	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;
	}
4252

4253
	mutex_unlock(&leader->child_mutex);
4254

4255
	ret = event->read_size;
4256 4257
	if (copy_to_user(buf, values, event->read_size))
		ret = -EFAULT;
4258
	goto out;
4259

4260 4261 4262
unlock:
	mutex_unlock(&leader->child_mutex);
out:
4263
	kfree(values);
4264
	return ret;
4265 4266
}

4267
static int perf_read_one(struct perf_event *event,
4268 4269
				 u64 read_format, char __user *buf)
{
4270
	u64 enabled, running;
4271 4272 4273
	u64 values[4];
	int n = 0;

4274 4275 4276 4277 4278
	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;
4279
	if (read_format & PERF_FORMAT_ID)
4280
		values[n++] = primary_event_id(event);
4281 4282 4283 4284 4285 4286 4287

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

	return n * sizeof(u64);
}

4288 4289 4290 4291
static bool is_event_hup(struct perf_event *event)
{
	bool no_children;

P
Peter Zijlstra 已提交
4292
	if (event->state > PERF_EVENT_STATE_EXIT)
4293 4294 4295 4296 4297 4298 4299 4300
		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
4301
/*
4302
 * Read the performance event - simple non blocking version for now
T
Thomas Gleixner 已提交
4303 4304
 */
static ssize_t
4305
__perf_read(struct perf_event *event, char __user *buf, size_t count)
T
Thomas Gleixner 已提交
4306
{
4307
	u64 read_format = event->attr.read_format;
4308
	int ret;
T
Thomas Gleixner 已提交
4309

4310
	/*
4311
	 * Return end-of-file for a read on a event that is in
4312 4313 4314
	 * error state (i.e. because it was pinned but it couldn't be
	 * scheduled on to the CPU at some point).
	 */
4315
	if (event->state == PERF_EVENT_STATE_ERROR)
4316 4317
		return 0;

4318
	if (count < event->read_size)
4319 4320
		return -ENOSPC;

4321
	WARN_ON_ONCE(event->ctx->parent_ctx);
4322
	if (read_format & PERF_FORMAT_GROUP)
4323
		ret = perf_read_group(event, read_format, buf);
4324
	else
4325
		ret = perf_read_one(event, read_format, buf);
T
Thomas Gleixner 已提交
4326

4327
	return ret;
T
Thomas Gleixner 已提交
4328 4329 4330 4331 4332
}

static ssize_t
perf_read(struct file *file, char __user *buf, size_t count, loff_t *ppos)
{
4333
	struct perf_event *event = file->private_data;
P
Peter Zijlstra 已提交
4334 4335
	struct perf_event_context *ctx;
	int ret;
T
Thomas Gleixner 已提交
4336

P
Peter Zijlstra 已提交
4337
	ctx = perf_event_ctx_lock(event);
4338
	ret = __perf_read(event, buf, count);
P
Peter Zijlstra 已提交
4339 4340 4341
	perf_event_ctx_unlock(event, ctx);

	return ret;
T
Thomas Gleixner 已提交
4342 4343 4344 4345
}

static unsigned int perf_poll(struct file *file, poll_table *wait)
{
4346
	struct perf_event *event = file->private_data;
4347
	struct ring_buffer *rb;
4348
	unsigned int events = POLLHUP;
P
Peter Zijlstra 已提交
4349

4350
	poll_wait(file, &event->waitq, wait);
4351

4352
	if (is_event_hup(event))
4353
		return events;
P
Peter Zijlstra 已提交
4354

4355
	/*
4356 4357
	 * Pin the event->rb by taking event->mmap_mutex; otherwise
	 * perf_event_set_output() can swizzle our rb and make us miss wakeups.
4358 4359
	 */
	mutex_lock(&event->mmap_mutex);
4360 4361
	rb = event->rb;
	if (rb)
4362
		events = atomic_xchg(&rb->poll, 0);
4363
	mutex_unlock(&event->mmap_mutex);
T
Thomas Gleixner 已提交
4364 4365 4366
	return events;
}

P
Peter Zijlstra 已提交
4367
static void _perf_event_reset(struct perf_event *event)
4368
{
4369
	(void)perf_event_read(event, false);
4370
	local64_set(&event->count, 0);
4371
	perf_event_update_userpage(event);
P
Peter Zijlstra 已提交
4372 4373
}

4374
/*
4375 4376
 * Holding the top-level event's child_mutex means that any
 * descendant process that has inherited this event will block
4377
 * in perf_event_exit_event() if it goes to exit, thus satisfying the
4378
 * task existence requirements of perf_event_enable/disable.
4379
 */
4380 4381
static void perf_event_for_each_child(struct perf_event *event,
					void (*func)(struct perf_event *))
P
Peter Zijlstra 已提交
4382
{
4383
	struct perf_event *child;
P
Peter Zijlstra 已提交
4384

4385
	WARN_ON_ONCE(event->ctx->parent_ctx);
P
Peter Zijlstra 已提交
4386

4387 4388 4389
	mutex_lock(&event->child_mutex);
	func(event);
	list_for_each_entry(child, &event->child_list, child_list)
P
Peter Zijlstra 已提交
4390
		func(child);
4391
	mutex_unlock(&event->child_mutex);
P
Peter Zijlstra 已提交
4392 4393
}

4394 4395
static void perf_event_for_each(struct perf_event *event,
				  void (*func)(struct perf_event *))
P
Peter Zijlstra 已提交
4396
{
4397 4398
	struct perf_event_context *ctx = event->ctx;
	struct perf_event *sibling;
P
Peter Zijlstra 已提交
4399

P
Peter Zijlstra 已提交
4400 4401
	lockdep_assert_held(&ctx->mutex);

4402
	event = event->group_leader;
4403

4404 4405
	perf_event_for_each_child(event, func);
	list_for_each_entry(sibling, &event->sibling_list, group_entry)
4406
		perf_event_for_each_child(sibling, func);
4407 4408
}

4409 4410 4411 4412
static void __perf_event_period(struct perf_event *event,
				struct perf_cpu_context *cpuctx,
				struct perf_event_context *ctx,
				void *info)
4413
{
4414
	u64 value = *((u64 *)info);
4415
	bool active;
4416

4417 4418
	if (event->attr.freq) {
		event->attr.sample_freq = value;
4419
	} else {
4420 4421
		event->attr.sample_period = value;
		event->hw.sample_period = value;
4422
	}
4423 4424 4425 4426

	active = (event->state == PERF_EVENT_STATE_ACTIVE);
	if (active) {
		perf_pmu_disable(ctx->pmu);
4427 4428 4429 4430 4431 4432 4433 4434
		/*
		 * 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);
		}
4435 4436 4437 4438 4439 4440 4441 4442 4443
		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);
	}
4444 4445 4446 4447 4448 4449 4450 4451 4452 4453 4454 4455 4456 4457 4458 4459 4460 4461
}

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;

4462
	event_function_call(event, __perf_event_period, &value);
4463

4464
	return 0;
4465 4466
}

4467 4468
static const struct file_operations perf_fops;

4469
static inline int perf_fget_light(int fd, struct fd *p)
4470
{
4471 4472 4473
	struct fd f = fdget(fd);
	if (!f.file)
		return -EBADF;
4474

4475 4476 4477
	if (f.file->f_op != &perf_fops) {
		fdput(f);
		return -EBADF;
4478
	}
4479 4480
	*p = f;
	return 0;
4481 4482 4483 4484
}

static int perf_event_set_output(struct perf_event *event,
				 struct perf_event *output_event);
L
Li Zefan 已提交
4485
static int perf_event_set_filter(struct perf_event *event, void __user *arg);
4486
static int perf_event_set_bpf_prog(struct perf_event *event, u32 prog_fd);
4487

P
Peter Zijlstra 已提交
4488
static long _perf_ioctl(struct perf_event *event, unsigned int cmd, unsigned long arg)
4489
{
4490
	void (*func)(struct perf_event *);
P
Peter Zijlstra 已提交
4491
	u32 flags = arg;
4492 4493

	switch (cmd) {
4494
	case PERF_EVENT_IOC_ENABLE:
P
Peter Zijlstra 已提交
4495
		func = _perf_event_enable;
4496
		break;
4497
	case PERF_EVENT_IOC_DISABLE:
P
Peter Zijlstra 已提交
4498
		func = _perf_event_disable;
4499
		break;
4500
	case PERF_EVENT_IOC_RESET:
P
Peter Zijlstra 已提交
4501
		func = _perf_event_reset;
4502
		break;
P
Peter Zijlstra 已提交
4503

4504
	case PERF_EVENT_IOC_REFRESH:
P
Peter Zijlstra 已提交
4505
		return _perf_event_refresh(event, arg);
4506

4507 4508
	case PERF_EVENT_IOC_PERIOD:
		return perf_event_period(event, (u64 __user *)arg);
4509

4510 4511 4512 4513 4514 4515 4516 4517 4518
	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;
	}

4519
	case PERF_EVENT_IOC_SET_OUTPUT:
4520 4521 4522
	{
		int ret;
		if (arg != -1) {
4523 4524 4525 4526 4527 4528 4529 4530 4531 4532
			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);
4533 4534 4535
		}
		return ret;
	}
4536

L
Li Zefan 已提交
4537 4538 4539
	case PERF_EVENT_IOC_SET_FILTER:
		return perf_event_set_filter(event, (void __user *)arg);

4540 4541 4542
	case PERF_EVENT_IOC_SET_BPF:
		return perf_event_set_bpf_prog(event, arg);

4543 4544 4545 4546 4547 4548 4549 4550 4551 4552 4553 4554 4555
	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;
	}
4556
	default:
P
Peter Zijlstra 已提交
4557
		return -ENOTTY;
4558
	}
P
Peter Zijlstra 已提交
4559 4560

	if (flags & PERF_IOC_FLAG_GROUP)
4561
		perf_event_for_each(event, func);
P
Peter Zijlstra 已提交
4562
	else
4563
		perf_event_for_each_child(event, func);
P
Peter Zijlstra 已提交
4564 4565

	return 0;
4566 4567
}

P
Peter Zijlstra 已提交
4568 4569 4570 4571 4572 4573 4574 4575 4576 4577 4578 4579 4580
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
4581 4582 4583 4584 4585 4586 4587 4588 4589 4590 4591 4592 4593 4594 4595 4596 4597 4598 4599 4600
#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

4601
int perf_event_task_enable(void)
4602
{
P
Peter Zijlstra 已提交
4603
	struct perf_event_context *ctx;
4604
	struct perf_event *event;
4605

4606
	mutex_lock(&current->perf_event_mutex);
P
Peter Zijlstra 已提交
4607 4608 4609 4610 4611
	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);
	}
4612
	mutex_unlock(&current->perf_event_mutex);
4613 4614 4615 4616

	return 0;
}

4617
int perf_event_task_disable(void)
4618
{
P
Peter Zijlstra 已提交
4619
	struct perf_event_context *ctx;
4620
	struct perf_event *event;
4621

4622
	mutex_lock(&current->perf_event_mutex);
P
Peter Zijlstra 已提交
4623 4624 4625 4626 4627
	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);
	}
4628
	mutex_unlock(&current->perf_event_mutex);
4629 4630 4631 4632

	return 0;
}

4633
static int perf_event_index(struct perf_event *event)
4634
{
P
Peter Zijlstra 已提交
4635 4636 4637
	if (event->hw.state & PERF_HES_STOPPED)
		return 0;

4638
	if (event->state != PERF_EVENT_STATE_ACTIVE)
4639 4640
		return 0;

4641
	return event->pmu->event_idx(event);
4642 4643
}

4644
static void calc_timer_values(struct perf_event *event,
4645
				u64 *now,
4646 4647
				u64 *enabled,
				u64 *running)
4648
{
4649
	u64 ctx_time;
4650

4651 4652
	*now = perf_clock();
	ctx_time = event->shadow_ctx_time + *now;
4653 4654 4655 4656
	*enabled = ctx_time - event->tstamp_enabled;
	*running = ctx_time - event->tstamp_running;
}

4657 4658 4659 4660 4661 4662 4663 4664 4665 4666 4667 4668 4669 4670 4671
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);
4672 4673
	userpg->data_offset = PAGE_SIZE;
	userpg->data_size = perf_data_size(rb);
4674 4675 4676 4677 4678

unlock:
	rcu_read_unlock();
}

4679 4680
void __weak arch_perf_update_userpage(
	struct perf_event *event, struct perf_event_mmap_page *userpg, u64 now)
4681 4682 4683
{
}

4684 4685 4686 4687 4688
/*
 * 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.
 */
4689
void perf_event_update_userpage(struct perf_event *event)
4690
{
4691
	struct perf_event_mmap_page *userpg;
4692
	struct ring_buffer *rb;
4693
	u64 enabled, running, now;
4694 4695

	rcu_read_lock();
4696 4697 4698 4699
	rb = rcu_dereference(event->rb);
	if (!rb)
		goto unlock;

4700 4701 4702 4703 4704 4705 4706 4707 4708
	/*
	 * 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
	 */
4709
	calc_timer_values(event, &now, &enabled, &running);
4710

4711
	userpg = rb->user_page;
4712 4713 4714 4715 4716
	/*
	 * Disable preemption so as to not let the corresponding user-space
	 * spin too long if we get preempted.
	 */
	preempt_disable();
4717
	++userpg->lock;
4718
	barrier();
4719
	userpg->index = perf_event_index(event);
P
Peter Zijlstra 已提交
4720
	userpg->offset = perf_event_count(event);
4721
	if (userpg->index)
4722
		userpg->offset -= local64_read(&event->hw.prev_count);
4723

4724
	userpg->time_enabled = enabled +
4725
			atomic64_read(&event->child_total_time_enabled);
4726

4727
	userpg->time_running = running +
4728
			atomic64_read(&event->child_total_time_running);
4729

4730
	arch_perf_update_userpage(event, userpg, now);
4731

4732
	barrier();
4733
	++userpg->lock;
4734
	preempt_enable();
4735
unlock:
4736
	rcu_read_unlock();
4737 4738
}

4739 4740 4741
static int perf_mmap_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
{
	struct perf_event *event = vma->vm_file->private_data;
4742
	struct ring_buffer *rb;
4743 4744 4745 4746 4747 4748 4749 4750 4751
	int ret = VM_FAULT_SIGBUS;

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

	rcu_read_lock();
4752 4753
	rb = rcu_dereference(event->rb);
	if (!rb)
4754 4755 4756 4757 4758
		goto unlock;

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

4759
	vmf->page = perf_mmap_to_page(rb, vmf->pgoff);
4760 4761 4762 4763 4764 4765 4766 4767 4768 4769 4770 4771 4772 4773
	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;
}

4774 4775 4776
static void ring_buffer_attach(struct perf_event *event,
			       struct ring_buffer *rb)
{
4777
	struct ring_buffer *old_rb = NULL;
4778 4779
	unsigned long flags;

4780 4781 4782 4783 4784 4785
	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);
4786

4787 4788 4789 4790
		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);
4791

4792 4793
		event->rcu_batches = get_state_synchronize_rcu();
		event->rcu_pending = 1;
4794
	}
4795

4796
	if (rb) {
4797 4798 4799 4800 4801
		if (event->rcu_pending) {
			cond_synchronize_rcu(event->rcu_batches);
			event->rcu_pending = 0;
		}

4802 4803 4804 4805 4806 4807 4808 4809 4810 4811 4812 4813 4814 4815 4816 4817
		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);
	}
4818 4819 4820 4821 4822 4823 4824 4825
}

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

	rcu_read_lock();
	rb = rcu_dereference(event->rb);
4826 4827 4828 4829
	if (rb) {
		list_for_each_entry_rcu(event, &rb->event_list, rb_entry)
			wake_up_all(&event->waitq);
	}
4830 4831 4832
	rcu_read_unlock();
}

4833
struct ring_buffer *ring_buffer_get(struct perf_event *event)
4834
{
4835
	struct ring_buffer *rb;
4836

4837
	rcu_read_lock();
4838 4839 4840 4841
	rb = rcu_dereference(event->rb);
	if (rb) {
		if (!atomic_inc_not_zero(&rb->refcount))
			rb = NULL;
4842 4843 4844
	}
	rcu_read_unlock();

4845
	return rb;
4846 4847
}

4848
void ring_buffer_put(struct ring_buffer *rb)
4849
{
4850
	if (!atomic_dec_and_test(&rb->refcount))
4851
		return;
4852

4853
	WARN_ON_ONCE(!list_empty(&rb->event_list));
4854

4855
	call_rcu(&rb->rcu_head, rb_free_rcu);
4856 4857 4858 4859
}

static void perf_mmap_open(struct vm_area_struct *vma)
{
4860
	struct perf_event *event = vma->vm_file->private_data;
4861

4862
	atomic_inc(&event->mmap_count);
4863
	atomic_inc(&event->rb->mmap_count);
4864

4865 4866 4867
	if (vma->vm_pgoff)
		atomic_inc(&event->rb->aux_mmap_count);

4868 4869
	if (event->pmu->event_mapped)
		event->pmu->event_mapped(event);
4870 4871
}

4872 4873
static void perf_pmu_output_stop(struct perf_event *event);

4874 4875 4876 4877 4878 4879 4880 4881
/*
 * 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.
 */
4882 4883
static void perf_mmap_close(struct vm_area_struct *vma)
{
4884
	struct perf_event *event = vma->vm_file->private_data;
4885

4886
	struct ring_buffer *rb = ring_buffer_get(event);
4887 4888 4889
	struct user_struct *mmap_user = rb->mmap_user;
	int mmap_locked = rb->mmap_locked;
	unsigned long size = perf_data_size(rb);
4890

4891 4892 4893
	if (event->pmu->event_unmapped)
		event->pmu->event_unmapped(event);

4894 4895 4896 4897 4898 4899 4900
	/*
	 * 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)) {
4901 4902 4903 4904 4905 4906 4907 4908 4909
		/*
		 * 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 */
4910 4911 4912
		atomic_long_sub(rb->aux_nr_pages, &mmap_user->locked_vm);
		vma->vm_mm->pinned_vm -= rb->aux_mmap_locked;

4913
		/* this has to be the last one */
4914
		rb_free_aux(rb);
4915 4916
		WARN_ON_ONCE(atomic_read(&rb->aux_refcount));

4917 4918 4919
		mutex_unlock(&event->mmap_mutex);
	}

4920 4921 4922
	atomic_dec(&rb->mmap_count);

	if (!atomic_dec_and_mutex_lock(&event->mmap_count, &event->mmap_mutex))
4923
		goto out_put;
4924

4925
	ring_buffer_attach(event, NULL);
4926 4927 4928
	mutex_unlock(&event->mmap_mutex);

	/* If there's still other mmap()s of this buffer, we're done. */
4929 4930
	if (atomic_read(&rb->mmap_count))
		goto out_put;
4931

4932 4933 4934 4935 4936 4937 4938 4939 4940 4941 4942 4943 4944 4945 4946 4947
	/*
	 * 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();
4948

4949 4950 4951 4952 4953 4954 4955 4956 4957 4958 4959
		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.
		 */
4960 4961 4962
		if (event->rb == rb)
			ring_buffer_attach(event, NULL);

4963
		mutex_unlock(&event->mmap_mutex);
4964
		put_event(event);
4965

4966 4967 4968 4969 4970
		/*
		 * Restart the iteration; either we're on the wrong list or
		 * destroyed its integrity by doing a deletion.
		 */
		goto again;
4971
	}
4972 4973 4974 4975 4976 4977 4978 4979 4980 4981 4982 4983 4984 4985 4986
	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);

4987
out_put:
4988
	ring_buffer_put(rb); /* could be last */
4989 4990
}

4991
static const struct vm_operations_struct perf_mmap_vmops = {
4992
	.open		= perf_mmap_open,
4993
	.close		= perf_mmap_close, /* non mergable */
4994 4995
	.fault		= perf_mmap_fault,
	.page_mkwrite	= perf_mmap_fault,
4996 4997 4998 4999
};

static int perf_mmap(struct file *file, struct vm_area_struct *vma)
{
5000
	struct perf_event *event = file->private_data;
5001
	unsigned long user_locked, user_lock_limit;
5002
	struct user_struct *user = current_user();
5003
	unsigned long locked, lock_limit;
5004
	struct ring_buffer *rb = NULL;
5005 5006
	unsigned long vma_size;
	unsigned long nr_pages;
5007
	long user_extra = 0, extra = 0;
5008
	int ret = 0, flags = 0;
5009

5010 5011 5012
	/*
	 * Don't allow mmap() of inherited per-task counters. This would
	 * create a performance issue due to all children writing to the
5013
	 * same rb.
5014 5015 5016 5017
	 */
	if (event->cpu == -1 && event->attr.inherit)
		return -EINVAL;

5018
	if (!(vma->vm_flags & VM_SHARED))
5019
		return -EINVAL;
5020 5021

	vma_size = vma->vm_end - vma->vm_start;
5022 5023 5024 5025 5026 5027 5028 5029 5030 5031 5032 5033 5034 5035 5036 5037 5038 5039 5040 5041 5042 5043 5044 5045 5046 5047 5048 5049 5050 5051 5052 5053 5054 5055 5056 5057 5058 5059 5060 5061 5062 5063 5064 5065 5066 5067 5068 5069 5070 5071 5072 5073 5074 5075 5076 5077 5078 5079 5080 5081

	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;
	}
5082

5083
	/*
5084
	 * If we have rb pages ensure they're a power-of-two number, so we
5085 5086
	 * can do bitmasks instead of modulo.
	 */
5087
	if (nr_pages != 0 && !is_power_of_2(nr_pages))
5088 5089
		return -EINVAL;

5090
	if (vma_size != PAGE_SIZE * (1 + nr_pages))
5091 5092
		return -EINVAL;

5093
	WARN_ON_ONCE(event->ctx->parent_ctx);
5094
again:
5095
	mutex_lock(&event->mmap_mutex);
5096
	if (event->rb) {
5097
		if (event->rb->nr_pages != nr_pages) {
5098
			ret = -EINVAL;
5099 5100 5101 5102 5103 5104 5105 5106 5107 5108 5109 5110 5111
			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;
		}

5112 5113 5114
		goto unlock;
	}

5115
	user_extra = nr_pages + 1;
5116 5117

accounting:
5118
	user_lock_limit = sysctl_perf_event_mlock >> (PAGE_SHIFT - 10);
I
Ingo Molnar 已提交
5119 5120 5121 5122 5123 5124

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

5125
	user_locked = atomic_long_read(&user->locked_vm) + user_extra;
5126

5127 5128
	if (user_locked > user_lock_limit)
		extra = user_locked - user_lock_limit;
5129

5130
	lock_limit = rlimit(RLIMIT_MEMLOCK);
5131
	lock_limit >>= PAGE_SHIFT;
5132
	locked = vma->vm_mm->pinned_vm + extra;
5133

5134 5135
	if ((locked > lock_limit) && perf_paranoid_tracepoint_raw() &&
		!capable(CAP_IPC_LOCK)) {
5136 5137 5138
		ret = -EPERM;
		goto unlock;
	}
5139

5140
	WARN_ON(!rb && event->rb);
5141

5142
	if (vma->vm_flags & VM_WRITE)
5143
		flags |= RING_BUFFER_WRITABLE;
5144

5145
	if (!rb) {
5146 5147 5148
		rb = rb_alloc(nr_pages,
			      event->attr.watermark ? event->attr.wakeup_watermark : 0,
			      event->cpu, flags);
P
Peter Zijlstra 已提交
5149

5150 5151 5152 5153
		if (!rb) {
			ret = -ENOMEM;
			goto unlock;
		}
5154

5155 5156 5157
		atomic_set(&rb->mmap_count, 1);
		rb->mmap_user = get_current_user();
		rb->mmap_locked = extra;
P
Peter Zijlstra 已提交
5158

5159
		ring_buffer_attach(event, rb);
5160

5161 5162 5163
		perf_event_init_userpage(event);
		perf_event_update_userpage(event);
	} else {
5164 5165
		ret = rb_alloc_aux(rb, event, vma->vm_pgoff, nr_pages,
				   event->attr.aux_watermark, flags);
5166 5167 5168
		if (!ret)
			rb->aux_mmap_locked = extra;
	}
5169

5170
unlock:
5171 5172 5173 5174
	if (!ret) {
		atomic_long_add(user_extra, &user->locked_vm);
		vma->vm_mm->pinned_vm += extra;

5175
		atomic_inc(&event->mmap_count);
5176 5177 5178 5179
	} else if (rb) {
		atomic_dec(&rb->mmap_count);
	}
aux_unlock:
5180
	mutex_unlock(&event->mmap_mutex);
5181

5182 5183 5184 5185
	/*
	 * Since pinned accounting is per vm we cannot allow fork() to copy our
	 * vma.
	 */
P
Peter Zijlstra 已提交
5186
	vma->vm_flags |= VM_DONTCOPY | VM_DONTEXPAND | VM_DONTDUMP;
5187
	vma->vm_ops = &perf_mmap_vmops;
5188

5189 5190 5191
	if (event->pmu->event_mapped)
		event->pmu->event_mapped(event);

5192
	return ret;
5193 5194
}

P
Peter Zijlstra 已提交
5195 5196
static int perf_fasync(int fd, struct file *filp, int on)
{
A
Al Viro 已提交
5197
	struct inode *inode = file_inode(filp);
5198
	struct perf_event *event = filp->private_data;
P
Peter Zijlstra 已提交
5199 5200
	int retval;

A
Al Viro 已提交
5201
	inode_lock(inode);
5202
	retval = fasync_helper(fd, filp, on, &event->fasync);
A
Al Viro 已提交
5203
	inode_unlock(inode);
P
Peter Zijlstra 已提交
5204 5205 5206 5207 5208 5209 5210

	if (retval < 0)
		return retval;

	return 0;
}

T
Thomas Gleixner 已提交
5211
static const struct file_operations perf_fops = {
5212
	.llseek			= no_llseek,
T
Thomas Gleixner 已提交
5213 5214 5215
	.release		= perf_release,
	.read			= perf_read,
	.poll			= perf_poll,
5216
	.unlocked_ioctl		= perf_ioctl,
P
Pawel Moll 已提交
5217
	.compat_ioctl		= perf_compat_ioctl,
5218
	.mmap			= perf_mmap,
P
Peter Zijlstra 已提交
5219
	.fasync			= perf_fasync,
T
Thomas Gleixner 已提交
5220 5221
};

5222
/*
5223
 * Perf event wakeup
5224 5225 5226 5227 5228
 *
 * If there's data, ensure we set the poll() state and publish everything
 * to user-space before waking everybody up.
 */

5229 5230 5231 5232 5233 5234 5235 5236
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;
}

5237
void perf_event_wakeup(struct perf_event *event)
5238
{
5239
	ring_buffer_wakeup(event);
5240

5241
	if (event->pending_kill) {
5242
		kill_fasync(perf_event_fasync(event), SIGIO, event->pending_kill);
5243
		event->pending_kill = 0;
5244
	}
5245 5246
}

5247
static void perf_pending_event(struct irq_work *entry)
5248
{
5249 5250
	struct perf_event *event = container_of(entry,
			struct perf_event, pending);
5251 5252 5253 5254 5255 5256 5257
	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'.
	 */
5258

5259 5260
	if (event->pending_disable) {
		event->pending_disable = 0;
5261
		perf_event_disable_local(event);
5262 5263
	}

5264 5265 5266
	if (event->pending_wakeup) {
		event->pending_wakeup = 0;
		perf_event_wakeup(event);
5267
	}
5268 5269 5270

	if (rctx >= 0)
		perf_swevent_put_recursion_context(rctx);
5271 5272
}

5273 5274 5275 5276 5277 5278 5279 5280 5281 5282 5283 5284 5285 5286 5287 5288 5289 5290 5291 5292 5293
/*
 * 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);

5294 5295 5296 5297 5298 5299 5300 5301 5302 5303 5304 5305 5306 5307 5308
static void
perf_output_sample_regs(struct perf_output_handle *handle,
			struct pt_regs *regs, u64 mask)
{
	int bit;

	for_each_set_bit(bit, (const unsigned long *) &mask,
			 sizeof(mask) * BITS_PER_BYTE) {
		u64 val;

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

5309
static void perf_sample_regs_user(struct perf_regs *regs_user,
5310 5311
				  struct pt_regs *regs,
				  struct pt_regs *regs_user_copy)
5312
{
5313 5314
	if (user_mode(regs)) {
		regs_user->abi = perf_reg_abi(current);
5315
		regs_user->regs = regs;
5316 5317
	} else if (current->mm) {
		perf_get_regs_user(regs_user, regs, regs_user_copy);
5318 5319 5320
	} else {
		regs_user->abi = PERF_SAMPLE_REGS_ABI_NONE;
		regs_user->regs = NULL;
5321 5322 5323
	}
}

5324 5325 5326 5327 5328 5329 5330 5331
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);
}


5332 5333 5334 5335 5336 5337 5338 5339 5340 5341 5342 5343 5344 5345 5346 5347 5348 5349 5350 5351 5352 5353 5354 5355 5356 5357 5358 5359 5360 5361 5362 5363 5364 5365 5366 5367 5368 5369 5370 5371 5372 5373 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
/*
 * 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);
	}
}

5427 5428 5429
static void __perf_event_header__init_id(struct perf_event_header *header,
					 struct perf_sample_data *data,
					 struct perf_event *event)
5430 5431 5432 5433 5434 5435 5436 5437 5438 5439 5440 5441 5442
{
	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)
5443
		data->time = perf_event_clock(event);
5444

5445
	if (sample_type & (PERF_SAMPLE_ID | PERF_SAMPLE_IDENTIFIER))
5446 5447 5448 5449 5450 5451 5452 5453 5454 5455 5456
		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;
	}
}

5457 5458 5459
void perf_event_header__init_id(struct perf_event_header *header,
				struct perf_sample_data *data,
				struct perf_event *event)
5460 5461 5462 5463 5464 5465 5466 5467 5468 5469 5470 5471 5472 5473 5474 5475 5476 5477 5478 5479 5480 5481 5482 5483
{
	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);
5484 5485 5486

	if (sample_type & PERF_SAMPLE_IDENTIFIER)
		perf_output_put(handle, data->id);
5487 5488
}

5489 5490 5491
void perf_event__output_id_sample(struct perf_event *event,
				  struct perf_output_handle *handle,
				  struct perf_sample_data *sample)
5492 5493 5494 5495 5496
{
	if (event->attr.sample_id_all)
		__perf_event__output_id_sample(handle, sample);
}

5497
static void perf_output_read_one(struct perf_output_handle *handle,
5498 5499
				 struct perf_event *event,
				 u64 enabled, u64 running)
5500
{
5501
	u64 read_format = event->attr.read_format;
5502 5503 5504
	u64 values[4];
	int n = 0;

P
Peter Zijlstra 已提交
5505
	values[n++] = perf_event_count(event);
5506
	if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED) {
5507
		values[n++] = enabled +
5508
			atomic64_read(&event->child_total_time_enabled);
5509 5510
	}
	if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING) {
5511
		values[n++] = running +
5512
			atomic64_read(&event->child_total_time_running);
5513 5514
	}
	if (read_format & PERF_FORMAT_ID)
5515
		values[n++] = primary_event_id(event);
5516

5517
	__output_copy(handle, values, n * sizeof(u64));
5518 5519 5520
}

/*
5521
 * XXX PERF_FORMAT_GROUP vs inherited events seems difficult.
5522 5523
 */
static void perf_output_read_group(struct perf_output_handle *handle,
5524 5525
			    struct perf_event *event,
			    u64 enabled, u64 running)
5526
{
5527 5528
	struct perf_event *leader = event->group_leader, *sub;
	u64 read_format = event->attr.read_format;
5529 5530 5531 5532 5533 5534
	u64 values[5];
	int n = 0;

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

	if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED)
5535
		values[n++] = enabled;
5536 5537

	if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING)
5538
		values[n++] = running;
5539

5540
	if (leader != event)
5541 5542
		leader->pmu->read(leader);

P
Peter Zijlstra 已提交
5543
	values[n++] = perf_event_count(leader);
5544
	if (read_format & PERF_FORMAT_ID)
5545
		values[n++] = primary_event_id(leader);
5546

5547
	__output_copy(handle, values, n * sizeof(u64));
5548

5549
	list_for_each_entry(sub, &leader->sibling_list, group_entry) {
5550 5551
		n = 0;

5552 5553
		if ((sub != event) &&
		    (sub->state == PERF_EVENT_STATE_ACTIVE))
5554 5555
			sub->pmu->read(sub);

P
Peter Zijlstra 已提交
5556
		values[n++] = perf_event_count(sub);
5557
		if (read_format & PERF_FORMAT_ID)
5558
			values[n++] = primary_event_id(sub);
5559

5560
		__output_copy(handle, values, n * sizeof(u64));
5561 5562 5563
	}
}

5564 5565 5566
#define PERF_FORMAT_TOTAL_TIMES (PERF_FORMAT_TOTAL_TIME_ENABLED|\
				 PERF_FORMAT_TOTAL_TIME_RUNNING)

5567
static void perf_output_read(struct perf_output_handle *handle,
5568
			     struct perf_event *event)
5569
{
5570
	u64 enabled = 0, running = 0, now;
5571 5572 5573 5574 5575 5576 5577 5578 5579 5580 5581
	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
	 */
5582
	if (read_format & PERF_FORMAT_TOTAL_TIMES)
5583
		calc_timer_values(event, &now, &enabled, &running);
5584

5585
	if (event->attr.read_format & PERF_FORMAT_GROUP)
5586
		perf_output_read_group(handle, event, enabled, running);
5587
	else
5588
		perf_output_read_one(handle, event, enabled, running);
5589 5590
}

5591 5592 5593
void perf_output_sample(struct perf_output_handle *handle,
			struct perf_event_header *header,
			struct perf_sample_data *data,
5594
			struct perf_event *event)
5595 5596 5597 5598 5599
{
	u64 sample_type = data->type;

	perf_output_put(handle, *header);

5600 5601 5602
	if (sample_type & PERF_SAMPLE_IDENTIFIER)
		perf_output_put(handle, data->id);

5603 5604 5605 5606 5607 5608 5609 5610 5611 5612 5613 5614 5615 5616 5617 5618 5619 5620 5621 5622 5623 5624 5625 5626 5627
	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)
5628
		perf_output_read(handle, event);
5629 5630 5631 5632 5633 5634 5635 5636 5637 5638

	if (sample_type & PERF_SAMPLE_CALLCHAIN) {
		if (data->callchain) {
			int size = 1;

			if (data->callchain)
				size += data->callchain->nr;

			size *= sizeof(u64);

5639
			__output_copy(handle, data->callchain, size);
5640 5641 5642 5643 5644 5645 5646
		} else {
			u64 nr = 0;
			perf_output_put(handle, nr);
		}
	}

	if (sample_type & PERF_SAMPLE_RAW) {
5647 5648 5649 5650 5651 5652 5653 5654 5655 5656 5657 5658 5659 5660 5661 5662 5663 5664 5665 5666
		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);
5667 5668 5669 5670 5671 5672 5673 5674 5675 5676 5677
		} else {
			struct {
				u32	size;
				u32	data;
			} raw = {
				.size = sizeof(u32),
				.data = 0,
			};
			perf_output_put(handle, raw);
		}
	}
5678

5679 5680 5681 5682 5683 5684 5685 5686 5687 5688 5689 5690 5691 5692 5693 5694 5695
	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);
		}
	}
5696 5697 5698 5699 5700 5701 5702 5703 5704 5705 5706 5707 5708 5709 5710 5711 5712

	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);
		}
	}
5713

5714
	if (sample_type & PERF_SAMPLE_STACK_USER) {
5715 5716 5717
		perf_output_sample_ustack(handle,
					  data->stack_user_size,
					  data->regs_user.regs);
5718
	}
A
Andi Kleen 已提交
5719 5720 5721

	if (sample_type & PERF_SAMPLE_WEIGHT)
		perf_output_put(handle, data->weight);
5722 5723 5724

	if (sample_type & PERF_SAMPLE_DATA_SRC)
		perf_output_put(handle, data->data_src.val);
5725

A
Andi Kleen 已提交
5726 5727 5728
	if (sample_type & PERF_SAMPLE_TRANSACTION)
		perf_output_put(handle, data->txn);

5729 5730 5731 5732 5733 5734 5735 5736 5737 5738 5739 5740 5741 5742 5743 5744 5745
	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);
		}
	}

5746 5747 5748 5749 5750 5751 5752 5753 5754 5755 5756 5757 5758
	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);
			}
		}
	}
5759 5760 5761 5762
}

void perf_prepare_sample(struct perf_event_header *header,
			 struct perf_sample_data *data,
5763
			 struct perf_event *event,
5764
			 struct pt_regs *regs)
5765
{
5766
	u64 sample_type = event->attr.sample_type;
5767

5768
	header->type = PERF_RECORD_SAMPLE;
5769
	header->size = sizeof(*header) + event->header_size;
5770 5771 5772

	header->misc = 0;
	header->misc |= perf_misc_flags(regs);
5773

5774
	__perf_event_header__init_id(header, data, event);
5775

5776
	if (sample_type & PERF_SAMPLE_IP)
5777 5778
		data->ip = perf_instruction_pointer(regs);

5779
	if (sample_type & PERF_SAMPLE_CALLCHAIN) {
5780
		int size = 1;
5781

5782
		data->callchain = perf_callchain(event, regs);
5783 5784 5785 5786 5787

		if (data->callchain)
			size += data->callchain->nr;

		header->size += size * sizeof(u64);
5788 5789
	}

5790
	if (sample_type & PERF_SAMPLE_RAW) {
5791 5792 5793 5794 5795 5796 5797 5798 5799 5800 5801 5802 5803 5804 5805 5806 5807 5808 5809 5810
		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);
		}
5811

5812
		header->size += size;
5813
	}
5814 5815 5816 5817 5818 5819 5820 5821 5822

	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;
	}
5823

5824
	if (sample_type & (PERF_SAMPLE_REGS_USER | PERF_SAMPLE_STACK_USER))
5825 5826
		perf_sample_regs_user(&data->regs_user, regs,
				      &data->regs_user_copy);
5827

5828 5829 5830 5831 5832 5833 5834 5835 5836 5837 5838
	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;
	}
5839 5840 5841 5842 5843 5844 5845 5846 5847 5848 5849 5850

	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,
5851
						     data->regs_user.regs);
5852 5853 5854 5855 5856 5857 5858 5859 5860 5861 5862 5863

		/*
		 * 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;
	}
5864 5865 5866 5867 5868 5869 5870 5871 5872 5873 5874 5875 5876 5877 5878

	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;
	}
5879
}
5880

5881 5882 5883 5884 5885 5886 5887
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))
5888 5889 5890
{
	struct perf_output_handle handle;
	struct perf_event_header header;
5891

5892 5893 5894
	/* protect the callchain buffers */
	rcu_read_lock();

5895
	perf_prepare_sample(&header, data, event, regs);
P
Peter Zijlstra 已提交
5896

5897
	if (output_begin(&handle, event, header.size))
5898
		goto exit;
5899

5900
	perf_output_sample(&handle, &header, data, event);
5901

5902
	perf_output_end(&handle);
5903 5904 5905

exit:
	rcu_read_unlock();
5906 5907
}

5908 5909 5910 5911 5912 5913 5914 5915 5916 5917 5918 5919 5920 5921 5922 5923 5924 5925 5926 5927 5928 5929 5930 5931
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);
}

5932
/*
5933
 * read event_id
5934 5935 5936 5937 5938 5939 5940 5941 5942 5943
 */

struct perf_read_event {
	struct perf_event_header	header;

	u32				pid;
	u32				tid;
};

static void
5944
perf_event_read_event(struct perf_event *event,
5945 5946 5947
			struct task_struct *task)
{
	struct perf_output_handle handle;
5948
	struct perf_sample_data sample;
5949
	struct perf_read_event read_event = {
5950
		.header = {
5951
			.type = PERF_RECORD_READ,
5952
			.misc = 0,
5953
			.size = sizeof(read_event) + event->read_size,
5954
		},
5955 5956
		.pid = perf_event_pid(event, task),
		.tid = perf_event_tid(event, task),
5957
	};
5958
	int ret;
5959

5960
	perf_event_header__init_id(&read_event.header, &sample, event);
5961
	ret = perf_output_begin(&handle, event, read_event.header.size);
5962 5963 5964
	if (ret)
		return;

5965
	perf_output_put(&handle, read_event);
5966
	perf_output_read(&handle, event);
5967
	perf_event__output_id_sample(event, &handle, &sample);
5968

5969 5970 5971
	perf_output_end(&handle);
}

5972
typedef void (perf_iterate_f)(struct perf_event *event, void *data);
5973 5974

static void
5975 5976
perf_iterate_ctx(struct perf_event_context *ctx,
		   perf_iterate_f output,
5977
		   void *data, bool all)
5978 5979 5980 5981
{
	struct perf_event *event;

	list_for_each_entry_rcu(event, &ctx->event_list, event_entry) {
5982 5983 5984 5985 5986 5987 5988
		if (!all) {
			if (event->state < PERF_EVENT_STATE_INACTIVE)
				continue;
			if (!event_filter_match(event))
				continue;
		}

5989
		output(event, data);
5990 5991 5992
	}
}

5993
static void perf_iterate_sb_cpu(perf_iterate_f output, void *data)
5994 5995 5996 5997 5998
{
	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) {
5999 6000 6001 6002 6003 6004 6005 6006
		/*
		 * 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;

6007 6008 6009 6010 6011 6012 6013 6014
		if (event->state < PERF_EVENT_STATE_INACTIVE)
			continue;
		if (!event_filter_match(event))
			continue;
		output(event, data);
	}
}

6015 6016 6017 6018 6019 6020
/*
 * 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.
 */
6021
static void
6022
perf_iterate_sb(perf_iterate_f output, void *data,
6023 6024 6025 6026 6027
	       struct perf_event_context *task_ctx)
{
	struct perf_event_context *ctx;
	int ctxn;

6028 6029 6030
	rcu_read_lock();
	preempt_disable();

J
Jiri Olsa 已提交
6031
	/*
6032 6033
	 * 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
6034 6035 6036
	 * context.
	 */
	if (task_ctx) {
6037 6038
		perf_iterate_ctx(task_ctx, output, data, false);
		goto done;
J
Jiri Olsa 已提交
6039 6040
	}

6041
	perf_iterate_sb_cpu(output, data);
6042 6043

	for_each_task_context_nr(ctxn) {
6044 6045
		ctx = rcu_dereference(current->perf_event_ctxp[ctxn]);
		if (ctx)
6046
			perf_iterate_ctx(ctx, output, data, false);
6047
	}
6048
done:
6049
	preempt_enable();
6050
	rcu_read_unlock();
6051 6052
}

6053 6054 6055 6056 6057 6058 6059 6060 6061 6062 6063 6064 6065 6066 6067 6068 6069 6070 6071 6072 6073 6074 6075 6076 6077 6078 6079 6080 6081 6082 6083 6084 6085 6086 6087 6088 6089 6090 6091 6092 6093 6094 6095 6096 6097
/*
 * 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);

6098
		perf_iterate_ctx(ctx, perf_event_addr_filters_exec, NULL,
6099 6100 6101 6102 6103
				   true);
	}
	rcu_read_unlock();
}

6104 6105 6106 6107 6108 6109 6110 6111 6112 6113
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;
6114 6115 6116
	struct stop_event_data sd = {
		.event	= event,
	};
6117 6118 6119 6120 6121 6122 6123 6124 6125 6126 6127 6128

	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)
6129
		ro->err = __perf_event_stop(&sd);
6130 6131 6132 6133 6134 6135 6136 6137 6138 6139 6140 6141
}

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();
6142
	perf_iterate_ctx(&cpuctx->ctx, __perf_event_output_stop, &ro, false);
6143
	if (cpuctx->task_ctx)
6144
		perf_iterate_ctx(cpuctx->task_ctx, __perf_event_output_stop,
6145
				   &ro, false);
6146 6147 6148 6149 6150 6151 6152 6153 6154 6155 6156 6157 6158 6159 6160 6161 6162 6163 6164 6165 6166 6167 6168 6169 6170 6171 6172 6173 6174 6175 6176 6177 6178
	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();
6179 6180
}

P
Peter Zijlstra 已提交
6181
/*
P
Peter Zijlstra 已提交
6182 6183
 * task tracking -- fork/exit
 *
6184
 * enabled by: attr.comm | attr.mmap | attr.mmap2 | attr.mmap_data | attr.task
P
Peter Zijlstra 已提交
6185 6186
 */

P
Peter Zijlstra 已提交
6187
struct perf_task_event {
6188
	struct task_struct		*task;
6189
	struct perf_event_context	*task_ctx;
P
Peter Zijlstra 已提交
6190 6191 6192 6193 6194 6195

	struct {
		struct perf_event_header	header;

		u32				pid;
		u32				ppid;
P
Peter Zijlstra 已提交
6196 6197
		u32				tid;
		u32				ptid;
6198
		u64				time;
6199
	} event_id;
P
Peter Zijlstra 已提交
6200 6201
};

6202 6203
static int perf_event_task_match(struct perf_event *event)
{
6204 6205 6206
	return event->attr.comm  || event->attr.mmap ||
	       event->attr.mmap2 || event->attr.mmap_data ||
	       event->attr.task;
6207 6208
}

6209
static void perf_event_task_output(struct perf_event *event,
6210
				   void *data)
P
Peter Zijlstra 已提交
6211
{
6212
	struct perf_task_event *task_event = data;
P
Peter Zijlstra 已提交
6213
	struct perf_output_handle handle;
6214
	struct perf_sample_data	sample;
P
Peter Zijlstra 已提交
6215
	struct task_struct *task = task_event->task;
6216
	int ret, size = task_event->event_id.header.size;
6217

6218 6219 6220
	if (!perf_event_task_match(event))
		return;

6221
	perf_event_header__init_id(&task_event->event_id.header, &sample, event);
P
Peter Zijlstra 已提交
6222

6223
	ret = perf_output_begin(&handle, event,
6224
				task_event->event_id.header.size);
6225
	if (ret)
6226
		goto out;
P
Peter Zijlstra 已提交
6227

6228 6229
	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
6230

6231 6232
	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
6233

6234 6235
	task_event->event_id.time = perf_event_clock(event);

6236
	perf_output_put(&handle, task_event->event_id);
6237

6238 6239
	perf_event__output_id_sample(event, &handle, &sample);

P
Peter Zijlstra 已提交
6240
	perf_output_end(&handle);
6241 6242
out:
	task_event->event_id.header.size = size;
P
Peter Zijlstra 已提交
6243 6244
}

6245 6246
static void perf_event_task(struct task_struct *task,
			      struct perf_event_context *task_ctx,
6247
			      int new)
P
Peter Zijlstra 已提交
6248
{
P
Peter Zijlstra 已提交
6249
	struct perf_task_event task_event;
P
Peter Zijlstra 已提交
6250

6251 6252 6253
	if (!atomic_read(&nr_comm_events) &&
	    !atomic_read(&nr_mmap_events) &&
	    !atomic_read(&nr_task_events))
P
Peter Zijlstra 已提交
6254 6255
		return;

P
Peter Zijlstra 已提交
6256
	task_event = (struct perf_task_event){
6257 6258
		.task	  = task,
		.task_ctx = task_ctx,
6259
		.event_id    = {
P
Peter Zijlstra 已提交
6260
			.header = {
6261
				.type = new ? PERF_RECORD_FORK : PERF_RECORD_EXIT,
6262
				.misc = 0,
6263
				.size = sizeof(task_event.event_id),
P
Peter Zijlstra 已提交
6264
			},
6265 6266
			/* .pid  */
			/* .ppid */
P
Peter Zijlstra 已提交
6267 6268
			/* .tid  */
			/* .ptid */
6269
			/* .time */
P
Peter Zijlstra 已提交
6270 6271 6272
		},
	};

6273
	perf_iterate_sb(perf_event_task_output,
6274 6275
		       &task_event,
		       task_ctx);
P
Peter Zijlstra 已提交
6276 6277
}

6278
void perf_event_fork(struct task_struct *task)
P
Peter Zijlstra 已提交
6279
{
6280
	perf_event_task(task, NULL, 1);
P
Peter Zijlstra 已提交
6281 6282
}

6283 6284 6285 6286 6287
/*
 * comm tracking
 */

struct perf_comm_event {
6288 6289
	struct task_struct	*task;
	char			*comm;
6290 6291 6292 6293 6294 6295 6296
	int			comm_size;

	struct {
		struct perf_event_header	header;

		u32				pid;
		u32				tid;
6297
	} event_id;
6298 6299
};

6300 6301 6302 6303 6304
static int perf_event_comm_match(struct perf_event *event)
{
	return event->attr.comm;
}

6305
static void perf_event_comm_output(struct perf_event *event,
6306
				   void *data)
6307
{
6308
	struct perf_comm_event *comm_event = data;
6309
	struct perf_output_handle handle;
6310
	struct perf_sample_data sample;
6311
	int size = comm_event->event_id.header.size;
6312 6313
	int ret;

6314 6315 6316
	if (!perf_event_comm_match(event))
		return;

6317 6318
	perf_event_header__init_id(&comm_event->event_id.header, &sample, event);
	ret = perf_output_begin(&handle, event,
6319
				comm_event->event_id.header.size);
6320 6321

	if (ret)
6322
		goto out;
6323

6324 6325
	comm_event->event_id.pid = perf_event_pid(event, comm_event->task);
	comm_event->event_id.tid = perf_event_tid(event, comm_event->task);
6326

6327
	perf_output_put(&handle, comm_event->event_id);
6328
	__output_copy(&handle, comm_event->comm,
6329
				   comm_event->comm_size);
6330 6331 6332

	perf_event__output_id_sample(event, &handle, &sample);

6333
	perf_output_end(&handle);
6334 6335
out:
	comm_event->event_id.header.size = size;
6336 6337
}

6338
static void perf_event_comm_event(struct perf_comm_event *comm_event)
6339
{
6340
	char comm[TASK_COMM_LEN];
6341 6342
	unsigned int size;

6343
	memset(comm, 0, sizeof(comm));
6344
	strlcpy(comm, comm_event->task->comm, sizeof(comm));
6345
	size = ALIGN(strlen(comm)+1, sizeof(u64));
6346 6347 6348 6349

	comm_event->comm = comm;
	comm_event->comm_size = size;

6350
	comm_event->event_id.header.size = sizeof(comm_event->event_id) + size;
P
Peter Zijlstra 已提交
6351

6352
	perf_iterate_sb(perf_event_comm_output,
6353 6354
		       comm_event,
		       NULL);
6355 6356
}

6357
void perf_event_comm(struct task_struct *task, bool exec)
6358
{
6359 6360
	struct perf_comm_event comm_event;

6361
	if (!atomic_read(&nr_comm_events))
6362
		return;
6363

6364
	comm_event = (struct perf_comm_event){
6365
		.task	= task,
6366 6367
		/* .comm      */
		/* .comm_size */
6368
		.event_id  = {
6369
			.header = {
6370
				.type = PERF_RECORD_COMM,
6371
				.misc = exec ? PERF_RECORD_MISC_COMM_EXEC : 0,
6372 6373 6374 6375
				/* .size */
			},
			/* .pid */
			/* .tid */
6376 6377 6378
		},
	};

6379
	perf_event_comm_event(&comm_event);
6380 6381
}

6382 6383 6384 6385 6386
/*
 * mmap tracking
 */

struct perf_mmap_event {
6387 6388 6389 6390
	struct vm_area_struct	*vma;

	const char		*file_name;
	int			file_size;
6391 6392 6393
	int			maj, min;
	u64			ino;
	u64			ino_generation;
6394
	u32			prot, flags;
6395 6396 6397 6398 6399 6400 6401 6402 6403

	struct {
		struct perf_event_header	header;

		u32				pid;
		u32				tid;
		u64				start;
		u64				len;
		u64				pgoff;
6404
	} event_id;
6405 6406
};

6407 6408 6409 6410 6411 6412 6413 6414
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) ||
6415
	       (executable && (event->attr.mmap || event->attr.mmap2));
6416 6417
}

6418
static void perf_event_mmap_output(struct perf_event *event,
6419
				   void *data)
6420
{
6421
	struct perf_mmap_event *mmap_event = data;
6422
	struct perf_output_handle handle;
6423
	struct perf_sample_data sample;
6424
	int size = mmap_event->event_id.header.size;
6425
	int ret;
6426

6427 6428 6429
	if (!perf_event_mmap_match(event, data))
		return;

6430 6431 6432 6433 6434
	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);
6435
		mmap_event->event_id.header.size += sizeof(mmap_event->ino_generation);
6436 6437
		mmap_event->event_id.header.size += sizeof(mmap_event->prot);
		mmap_event->event_id.header.size += sizeof(mmap_event->flags);
6438 6439
	}

6440 6441
	perf_event_header__init_id(&mmap_event->event_id.header, &sample, event);
	ret = perf_output_begin(&handle, event,
6442
				mmap_event->event_id.header.size);
6443
	if (ret)
6444
		goto out;
6445

6446 6447
	mmap_event->event_id.pid = perf_event_pid(event, current);
	mmap_event->event_id.tid = perf_event_tid(event, current);
6448

6449
	perf_output_put(&handle, mmap_event->event_id);
6450 6451 6452 6453 6454 6455

	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);
6456 6457
		perf_output_put(&handle, mmap_event->prot);
		perf_output_put(&handle, mmap_event->flags);
6458 6459
	}

6460
	__output_copy(&handle, mmap_event->file_name,
6461
				   mmap_event->file_size);
6462 6463 6464

	perf_event__output_id_sample(event, &handle, &sample);

6465
	perf_output_end(&handle);
6466 6467
out:
	mmap_event->event_id.header.size = size;
6468 6469
}

6470
static void perf_event_mmap_event(struct perf_mmap_event *mmap_event)
6471
{
6472 6473
	struct vm_area_struct *vma = mmap_event->vma;
	struct file *file = vma->vm_file;
6474 6475
	int maj = 0, min = 0;
	u64 ino = 0, gen = 0;
6476
	u32 prot = 0, flags = 0;
6477 6478 6479
	unsigned int size;
	char tmp[16];
	char *buf = NULL;
6480
	char *name;
6481

6482
	if (file) {
6483 6484
		struct inode *inode;
		dev_t dev;
6485

6486
		buf = kmalloc(PATH_MAX, GFP_KERNEL);
6487
		if (!buf) {
6488 6489
			name = "//enomem";
			goto cpy_name;
6490
		}
6491
		/*
6492
		 * d_path() works from the end of the rb backwards, so we
6493 6494 6495
		 * need to add enough zero bytes after the string to handle
		 * the 64bit alignment we do later.
		 */
M
Miklos Szeredi 已提交
6496
		name = file_path(file, buf, PATH_MAX - sizeof(u64));
6497
		if (IS_ERR(name)) {
6498 6499
			name = "//toolong";
			goto cpy_name;
6500
		}
6501 6502 6503 6504 6505 6506
		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);
6507 6508 6509 6510 6511 6512 6513 6514 6515 6516 6517 6518 6519 6520 6521 6522 6523 6524 6525 6526 6527 6528

		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;

6529
		goto got_name;
6530
	} else {
6531 6532 6533 6534 6535 6536
		if (vma->vm_ops && vma->vm_ops->name) {
			name = (char *) vma->vm_ops->name(vma);
			if (name)
				goto cpy_name;
		}

6537
		name = (char *)arch_vma_name(vma);
6538 6539
		if (name)
			goto cpy_name;
6540

6541
		if (vma->vm_start <= vma->vm_mm->start_brk &&
6542
				vma->vm_end >= vma->vm_mm->brk) {
6543 6544
			name = "[heap]";
			goto cpy_name;
6545 6546
		}
		if (vma->vm_start <= vma->vm_mm->start_stack &&
6547
				vma->vm_end >= vma->vm_mm->start_stack) {
6548 6549
			name = "[stack]";
			goto cpy_name;
6550 6551
		}

6552 6553
		name = "//anon";
		goto cpy_name;
6554 6555
	}

6556 6557 6558
cpy_name:
	strlcpy(tmp, name, sizeof(tmp));
	name = tmp;
6559
got_name:
6560 6561 6562 6563 6564 6565 6566 6567
	/*
	 * 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';
6568 6569 6570

	mmap_event->file_name = name;
	mmap_event->file_size = size;
6571 6572 6573 6574
	mmap_event->maj = maj;
	mmap_event->min = min;
	mmap_event->ino = ino;
	mmap_event->ino_generation = gen;
6575 6576
	mmap_event->prot = prot;
	mmap_event->flags = flags;
6577

6578 6579 6580
	if (!(vma->vm_flags & VM_EXEC))
		mmap_event->event_id.header.misc |= PERF_RECORD_MISC_MMAP_DATA;

6581
	mmap_event->event_id.header.size = sizeof(mmap_event->event_id) + size;
6582

6583
	perf_iterate_sb(perf_event_mmap_output,
6584 6585
		       mmap_event,
		       NULL);
6586

6587 6588 6589
	kfree(buf);
}

6590 6591 6592 6593 6594 6595 6596 6597 6598 6599 6600 6601 6602 6603 6604 6605 6606 6607 6608 6609 6610 6611 6612 6613 6614 6615 6616 6617 6618 6619 6620 6621 6622 6623 6624 6625 6626 6627 6628 6629 6630 6631 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
/*
 * Whether this @filter depends on a dynamic object which is not loaded
 * yet or its load addresses are not known.
 */
static bool perf_addr_filter_needs_mmap(struct perf_addr_filter *filter)
{
	return filter->filter && filter->inode;
}

/*
 * 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;

	rcu_read_lock();
	for_each_task_context_nr(ctxn) {
		ctx = rcu_dereference(current->perf_event_ctxp[ctxn]);
		if (!ctx)
			continue;

6666
		perf_iterate_ctx(ctx, __perf_addr_filters_adjust, vma, true);
6667 6668 6669 6670
	}
	rcu_read_unlock();
}

6671
void perf_event_mmap(struct vm_area_struct *vma)
6672
{
6673 6674
	struct perf_mmap_event mmap_event;

6675
	if (!atomic_read(&nr_mmap_events))
6676 6677 6678
		return;

	mmap_event = (struct perf_mmap_event){
6679
		.vma	= vma,
6680 6681
		/* .file_name */
		/* .file_size */
6682
		.event_id  = {
6683
			.header = {
6684
				.type = PERF_RECORD_MMAP,
6685
				.misc = PERF_RECORD_MISC_USER,
6686 6687 6688 6689
				/* .size */
			},
			/* .pid */
			/* .tid */
6690 6691
			.start  = vma->vm_start,
			.len    = vma->vm_end - vma->vm_start,
6692
			.pgoff  = (u64)vma->vm_pgoff << PAGE_SHIFT,
6693
		},
6694 6695 6696 6697
		/* .maj (attr_mmap2 only) */
		/* .min (attr_mmap2 only) */
		/* .ino (attr_mmap2 only) */
		/* .ino_generation (attr_mmap2 only) */
6698 6699
		/* .prot (attr_mmap2 only) */
		/* .flags (attr_mmap2 only) */
6700 6701
	};

6702
	perf_addr_filters_adjust(vma);
6703
	perf_event_mmap_event(&mmap_event);
6704 6705
}

A
Alexander Shishkin 已提交
6706 6707 6708 6709 6710 6711 6712 6713 6714 6715 6716 6717 6718 6719 6720 6721 6722 6723 6724 6725 6726 6727 6728 6729 6730 6731 6732 6733 6734 6735 6736 6737 6738 6739
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);
}

6740 6741 6742 6743 6744 6745 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
/*
 * 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);
}

6773 6774 6775 6776 6777 6778 6779 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 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
/*
 * 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 */
		},
	};

6853
	perf_iterate_sb(perf_event_switch_output,
6854 6855 6856 6857
		       &switch_event,
		       NULL);
}

6858 6859 6860 6861
/*
 * IRQ throttle logging
 */

6862
static void perf_log_throttle(struct perf_event *event, int enable)
6863 6864
{
	struct perf_output_handle handle;
6865
	struct perf_sample_data sample;
6866 6867 6868 6869 6870
	int ret;

	struct {
		struct perf_event_header	header;
		u64				time;
6871
		u64				id;
6872
		u64				stream_id;
6873 6874
	} throttle_event = {
		.header = {
6875
			.type = PERF_RECORD_THROTTLE,
6876 6877 6878
			.misc = 0,
			.size = sizeof(throttle_event),
		},
6879
		.time		= perf_event_clock(event),
6880 6881
		.id		= primary_event_id(event),
		.stream_id	= event->id,
6882 6883
	};

6884
	if (enable)
6885
		throttle_event.header.type = PERF_RECORD_UNTHROTTLE;
6886

6887 6888 6889
	perf_event_header__init_id(&throttle_event.header, &sample, event);

	ret = perf_output_begin(&handle, event,
6890
				throttle_event.header.size);
6891 6892 6893 6894
	if (ret)
		return;

	perf_output_put(&handle, throttle_event);
6895
	perf_event__output_id_sample(event, &handle, &sample);
6896 6897 6898
	perf_output_end(&handle);
}

6899 6900 6901 6902 6903 6904 6905 6906 6907 6908 6909 6910 6911 6912 6913 6914 6915 6916 6917 6918 6919 6920 6921 6922 6923 6924 6925 6926 6927 6928 6929 6930 6931 6932 6933 6934
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);
}

6935
/*
6936
 * Generic event overflow handling, sampling.
6937 6938
 */

6939
static int __perf_event_overflow(struct perf_event *event,
6940 6941
				   int throttle, struct perf_sample_data *data,
				   struct pt_regs *regs)
6942
{
6943 6944
	int events = atomic_read(&event->event_limit);
	struct hw_perf_event *hwc = &event->hw;
6945
	u64 seq;
6946 6947
	int ret = 0;

6948 6949 6950 6951 6952 6953 6954
	/*
	 * Non-sampling counters might still use the PMI to fold short
	 * hardware counters, ignore those.
	 */
	if (unlikely(!is_sampling_event(event)))
		return 0;

6955 6956 6957 6958 6959 6960 6961 6962 6963
	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);
6964
			tick_dep_set_cpu(smp_processor_id(), TICK_DEP_BIT_PERF_EVENTS);
P
Peter Zijlstra 已提交
6965 6966
			hwc->interrupts = MAX_INTERRUPTS;
			perf_log_throttle(event, 0);
6967 6968
			ret = 1;
		}
6969
	}
6970

6971
	if (event->attr.freq) {
P
Peter Zijlstra 已提交
6972
		u64 now = perf_clock();
6973
		s64 delta = now - hwc->freq_time_stamp;
6974

6975
		hwc->freq_time_stamp = now;
6976

6977
		if (delta > 0 && delta < 2*TICK_NSEC)
6978
			perf_adjust_period(event, delta, hwc->last_period, true);
6979 6980
	}

6981 6982
	/*
	 * XXX event_limit might not quite work as expected on inherited
6983
	 * events
6984 6985
	 */

6986 6987
	event->pending_kill = POLL_IN;
	if (events && atomic_dec_and_test(&event->event_limit)) {
6988
		ret = 1;
6989
		event->pending_kill = POLL_HUP;
6990 6991
		event->pending_disable = 1;
		irq_work_queue(&event->pending);
6992 6993
	}

6994
	event->overflow_handler(event, data, regs);
6995

6996
	if (*perf_event_fasync(event) && event->pending_kill) {
6997 6998
		event->pending_wakeup = 1;
		irq_work_queue(&event->pending);
P
Peter Zijlstra 已提交
6999 7000
	}

7001
	return ret;
7002 7003
}

7004
int perf_event_overflow(struct perf_event *event,
7005 7006
			  struct perf_sample_data *data,
			  struct pt_regs *regs)
7007
{
7008
	return __perf_event_overflow(event, 1, data, regs);
7009 7010
}

7011
/*
7012
 * Generic software event infrastructure
7013 7014
 */

7015 7016 7017 7018 7019 7020 7021 7022 7023 7024 7025
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);

7026
/*
7027 7028
 * We directly increment event->count and keep a second value in
 * event->hw.period_left to count intervals. This period event
7029 7030 7031 7032
 * is kept in the range [-sample_period, 0] so that we can use the
 * sign as trigger.
 */

7033
u64 perf_swevent_set_period(struct perf_event *event)
7034
{
7035
	struct hw_perf_event *hwc = &event->hw;
7036 7037 7038 7039 7040
	u64 period = hwc->last_period;
	u64 nr, offset;
	s64 old, val;

	hwc->last_period = hwc->sample_period;
7041 7042

again:
7043
	old = val = local64_read(&hwc->period_left);
7044 7045
	if (val < 0)
		return 0;
7046

7047 7048 7049
	nr = div64_u64(period + val, period);
	offset = nr * period;
	val -= offset;
7050
	if (local64_cmpxchg(&hwc->period_left, old, val) != old)
7051
		goto again;
7052

7053
	return nr;
7054 7055
}

7056
static void perf_swevent_overflow(struct perf_event *event, u64 overflow,
7057
				    struct perf_sample_data *data,
7058
				    struct pt_regs *regs)
7059
{
7060
	struct hw_perf_event *hwc = &event->hw;
7061
	int throttle = 0;
7062

7063 7064
	if (!overflow)
		overflow = perf_swevent_set_period(event);
7065

7066 7067
	if (hwc->interrupts == MAX_INTERRUPTS)
		return;
7068

7069
	for (; overflow; overflow--) {
7070
		if (__perf_event_overflow(event, throttle,
7071
					    data, regs)) {
7072 7073 7074 7075 7076 7077
			/*
			 * We inhibit the overflow from happening when
			 * hwc->interrupts == MAX_INTERRUPTS.
			 */
			break;
		}
7078
		throttle = 1;
7079
	}
7080 7081
}

P
Peter Zijlstra 已提交
7082
static void perf_swevent_event(struct perf_event *event, u64 nr,
7083
			       struct perf_sample_data *data,
7084
			       struct pt_regs *regs)
7085
{
7086
	struct hw_perf_event *hwc = &event->hw;
7087

7088
	local64_add(nr, &event->count);
7089

7090 7091 7092
	if (!regs)
		return;

7093
	if (!is_sampling_event(event))
7094
		return;
7095

7096 7097 7098 7099 7100 7101
	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;

7102
	if (nr == 1 && hwc->sample_period == 1 && !event->attr.freq)
7103
		return perf_swevent_overflow(event, 1, data, regs);
7104

7105
	if (local64_add_negative(nr, &hwc->period_left))
7106
		return;
7107

7108
	perf_swevent_overflow(event, 0, data, regs);
7109 7110
}

7111 7112 7113
static int perf_exclude_event(struct perf_event *event,
			      struct pt_regs *regs)
{
P
Peter Zijlstra 已提交
7114
	if (event->hw.state & PERF_HES_STOPPED)
7115
		return 1;
P
Peter Zijlstra 已提交
7116

7117 7118 7119 7120 7121 7122 7123 7124 7125 7126 7127
	if (regs) {
		if (event->attr.exclude_user && user_mode(regs))
			return 1;

		if (event->attr.exclude_kernel && !user_mode(regs))
			return 1;
	}

	return 0;
}

7128
static int perf_swevent_match(struct perf_event *event,
P
Peter Zijlstra 已提交
7129
				enum perf_type_id type,
L
Li Zefan 已提交
7130 7131 7132
				u32 event_id,
				struct perf_sample_data *data,
				struct pt_regs *regs)
7133
{
7134
	if (event->attr.type != type)
7135
		return 0;
7136

7137
	if (event->attr.config != event_id)
7138 7139
		return 0;

7140 7141
	if (perf_exclude_event(event, regs))
		return 0;
7142 7143 7144 7145

	return 1;
}

7146 7147 7148 7149 7150 7151 7152
static inline u64 swevent_hash(u64 type, u32 event_id)
{
	u64 val = event_id | (type << 32);

	return hash_64(val, SWEVENT_HLIST_BITS);
}

7153 7154
static inline struct hlist_head *
__find_swevent_head(struct swevent_hlist *hlist, u64 type, u32 event_id)
7155
{
7156 7157 7158 7159
	u64 hash = swevent_hash(type, event_id);

	return &hlist->heads[hash];
}
7160

7161 7162
/* For the read side: events when they trigger */
static inline struct hlist_head *
7163
find_swevent_head_rcu(struct swevent_htable *swhash, u64 type, u32 event_id)
7164 7165
{
	struct swevent_hlist *hlist;
7166

7167
	hlist = rcu_dereference(swhash->swevent_hlist);
7168 7169 7170
	if (!hlist)
		return NULL;

7171 7172 7173 7174 7175
	return __find_swevent_head(hlist, type, event_id);
}

/* For the event head insertion and removal in the hlist */
static inline struct hlist_head *
7176
find_swevent_head(struct swevent_htable *swhash, struct perf_event *event)
7177 7178 7179 7180 7181 7182 7183 7184 7185 7186
{
	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.
	 */
7187
	hlist = rcu_dereference_protected(swhash->swevent_hlist,
7188 7189 7190 7191 7192
					  lockdep_is_held(&event->ctx->lock));
	if (!hlist)
		return NULL;

	return __find_swevent_head(hlist, type, event_id);
7193 7194 7195
}

static void do_perf_sw_event(enum perf_type_id type, u32 event_id,
7196
				    u64 nr,
7197 7198
				    struct perf_sample_data *data,
				    struct pt_regs *regs)
7199
{
7200
	struct swevent_htable *swhash = this_cpu_ptr(&swevent_htable);
7201
	struct perf_event *event;
7202
	struct hlist_head *head;
7203

7204
	rcu_read_lock();
7205
	head = find_swevent_head_rcu(swhash, type, event_id);
7206 7207 7208
	if (!head)
		goto end;

7209
	hlist_for_each_entry_rcu(event, head, hlist_entry) {
L
Li Zefan 已提交
7210
		if (perf_swevent_match(event, type, event_id, data, regs))
7211
			perf_swevent_event(event, nr, data, regs);
7212
	}
7213 7214
end:
	rcu_read_unlock();
7215 7216
}

7217 7218
DEFINE_PER_CPU(struct pt_regs, __perf_regs[4]);

7219
int perf_swevent_get_recursion_context(void)
P
Peter Zijlstra 已提交
7220
{
7221
	struct swevent_htable *swhash = this_cpu_ptr(&swevent_htable);
P
Peter Zijlstra 已提交
7222

7223
	return get_recursion_context(swhash->recursion);
P
Peter Zijlstra 已提交
7224
}
I
Ingo Molnar 已提交
7225
EXPORT_SYMBOL_GPL(perf_swevent_get_recursion_context);
P
Peter Zijlstra 已提交
7226

7227
void perf_swevent_put_recursion_context(int rctx)
7228
{
7229
	struct swevent_htable *swhash = this_cpu_ptr(&swevent_htable);
7230

7231
	put_recursion_context(swhash->recursion, rctx);
7232
}
7233

7234
void ___perf_sw_event(u32 event_id, u64 nr, struct pt_regs *regs, u64 addr)
7235
{
7236
	struct perf_sample_data data;
7237

7238
	if (WARN_ON_ONCE(!regs))
7239
		return;
7240

7241
	perf_sample_data_init(&data, addr, 0);
7242
	do_perf_sw_event(PERF_TYPE_SOFTWARE, event_id, nr, &data, regs);
7243 7244 7245 7246 7247 7248 7249 7250 7251 7252 7253 7254
}

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);
7255 7256

	perf_swevent_put_recursion_context(rctx);
7257
fail:
7258
	preempt_enable_notrace();
7259 7260
}

7261
static void perf_swevent_read(struct perf_event *event)
7262 7263 7264
{
}

P
Peter Zijlstra 已提交
7265
static int perf_swevent_add(struct perf_event *event, int flags)
7266
{
7267
	struct swevent_htable *swhash = this_cpu_ptr(&swevent_htable);
7268
	struct hw_perf_event *hwc = &event->hw;
7269 7270
	struct hlist_head *head;

7271
	if (is_sampling_event(event)) {
7272
		hwc->last_period = hwc->sample_period;
7273
		perf_swevent_set_period(event);
7274
	}
7275

P
Peter Zijlstra 已提交
7276 7277
	hwc->state = !(flags & PERF_EF_START);

7278
	head = find_swevent_head(swhash, event);
P
Peter Zijlstra 已提交
7279
	if (WARN_ON_ONCE(!head))
7280 7281 7282
		return -EINVAL;

	hlist_add_head_rcu(&event->hlist_entry, head);
7283
	perf_event_update_userpage(event);
7284

7285 7286 7287
	return 0;
}

P
Peter Zijlstra 已提交
7288
static void perf_swevent_del(struct perf_event *event, int flags)
7289
{
7290
	hlist_del_rcu(&event->hlist_entry);
7291 7292
}

P
Peter Zijlstra 已提交
7293
static void perf_swevent_start(struct perf_event *event, int flags)
7294
{
P
Peter Zijlstra 已提交
7295
	event->hw.state = 0;
7296
}
I
Ingo Molnar 已提交
7297

P
Peter Zijlstra 已提交
7298
static void perf_swevent_stop(struct perf_event *event, int flags)
7299
{
P
Peter Zijlstra 已提交
7300
	event->hw.state = PERF_HES_STOPPED;
7301 7302
}

7303 7304
/* Deref the hlist from the update side */
static inline struct swevent_hlist *
7305
swevent_hlist_deref(struct swevent_htable *swhash)
7306
{
7307 7308
	return rcu_dereference_protected(swhash->swevent_hlist,
					 lockdep_is_held(&swhash->hlist_mutex));
7309 7310
}

7311
static void swevent_hlist_release(struct swevent_htable *swhash)
7312
{
7313
	struct swevent_hlist *hlist = swevent_hlist_deref(swhash);
7314

7315
	if (!hlist)
7316 7317
		return;

7318
	RCU_INIT_POINTER(swhash->swevent_hlist, NULL);
7319
	kfree_rcu(hlist, rcu_head);
7320 7321
}

7322
static void swevent_hlist_put_cpu(int cpu)
7323
{
7324
	struct swevent_htable *swhash = &per_cpu(swevent_htable, cpu);
7325

7326
	mutex_lock(&swhash->hlist_mutex);
7327

7328 7329
	if (!--swhash->hlist_refcount)
		swevent_hlist_release(swhash);
7330

7331
	mutex_unlock(&swhash->hlist_mutex);
7332 7333
}

7334
static void swevent_hlist_put(void)
7335 7336 7337 7338
{
	int cpu;

	for_each_possible_cpu(cpu)
7339
		swevent_hlist_put_cpu(cpu);
7340 7341
}

7342
static int swevent_hlist_get_cpu(int cpu)
7343
{
7344
	struct swevent_htable *swhash = &per_cpu(swevent_htable, cpu);
7345 7346
	int err = 0;

7347 7348
	mutex_lock(&swhash->hlist_mutex);
	if (!swevent_hlist_deref(swhash) && cpu_online(cpu)) {
7349 7350 7351 7352 7353 7354 7355
		struct swevent_hlist *hlist;

		hlist = kzalloc(sizeof(*hlist), GFP_KERNEL);
		if (!hlist) {
			err = -ENOMEM;
			goto exit;
		}
7356
		rcu_assign_pointer(swhash->swevent_hlist, hlist);
7357
	}
7358
	swhash->hlist_refcount++;
P
Peter Zijlstra 已提交
7359
exit:
7360
	mutex_unlock(&swhash->hlist_mutex);
7361 7362 7363 7364

	return err;
}

7365
static int swevent_hlist_get(void)
7366
{
7367
	int err, cpu, failed_cpu;
7368 7369 7370

	get_online_cpus();
	for_each_possible_cpu(cpu) {
7371
		err = swevent_hlist_get_cpu(cpu);
7372 7373 7374 7375 7376 7377 7378 7379
		if (err) {
			failed_cpu = cpu;
			goto fail;
		}
	}
	put_online_cpus();

	return 0;
P
Peter Zijlstra 已提交
7380
fail:
7381 7382 7383
	for_each_possible_cpu(cpu) {
		if (cpu == failed_cpu)
			break;
7384
		swevent_hlist_put_cpu(cpu);
7385 7386 7387 7388 7389 7390
	}

	put_online_cpus();
	return err;
}

7391
struct static_key perf_swevent_enabled[PERF_COUNT_SW_MAX];
7392

7393 7394 7395
static void sw_perf_event_destroy(struct perf_event *event)
{
	u64 event_id = event->attr.config;
7396

7397 7398
	WARN_ON(event->parent);

7399
	static_key_slow_dec(&perf_swevent_enabled[event_id]);
7400
	swevent_hlist_put();
7401 7402 7403 7404
}

static int perf_swevent_init(struct perf_event *event)
{
7405
	u64 event_id = event->attr.config;
7406 7407 7408 7409

	if (event->attr.type != PERF_TYPE_SOFTWARE)
		return -ENOENT;

7410 7411 7412 7413 7414 7415
	/*
	 * no branch sampling for software events
	 */
	if (has_branch_stack(event))
		return -EOPNOTSUPP;

7416 7417 7418 7419 7420 7421 7422 7423 7424
	switch (event_id) {
	case PERF_COUNT_SW_CPU_CLOCK:
	case PERF_COUNT_SW_TASK_CLOCK:
		return -ENOENT;

	default:
		break;
	}

7425
	if (event_id >= PERF_COUNT_SW_MAX)
7426 7427 7428 7429 7430
		return -ENOENT;

	if (!event->parent) {
		int err;

7431
		err = swevent_hlist_get();
7432 7433 7434
		if (err)
			return err;

7435
		static_key_slow_inc(&perf_swevent_enabled[event_id]);
7436 7437 7438 7439 7440 7441 7442
		event->destroy = sw_perf_event_destroy;
	}

	return 0;
}

static struct pmu perf_swevent = {
7443
	.task_ctx_nr	= perf_sw_context,
7444

7445 7446
	.capabilities	= PERF_PMU_CAP_NO_NMI,

7447
	.event_init	= perf_swevent_init,
P
Peter Zijlstra 已提交
7448 7449 7450 7451
	.add		= perf_swevent_add,
	.del		= perf_swevent_del,
	.start		= perf_swevent_start,
	.stop		= perf_swevent_stop,
7452 7453 7454
	.read		= perf_swevent_read,
};

7455 7456
#ifdef CONFIG_EVENT_TRACING

7457 7458 7459
static int perf_tp_filter_match(struct perf_event *event,
				struct perf_sample_data *data)
{
7460
	void *record = data->raw->frag.data;
7461

7462 7463 7464 7465
	/* only top level events have filters set */
	if (event->parent)
		event = event->parent;

7466 7467 7468 7469 7470 7471 7472 7473 7474
	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)
{
7475 7476
	if (event->hw.state & PERF_HES_STOPPED)
		return 0;
7477 7478 7479 7480
	/*
	 * All tracepoints are from kernel-space.
	 */
	if (event->attr.exclude_kernel)
7481 7482 7483 7484 7485 7486 7487 7488
		return 0;

	if (!perf_tp_filter_match(event, data))
		return 0;

	return 1;
}

7489 7490 7491 7492 7493 7494 7495 7496 7497 7498 7499 7500 7501 7502 7503 7504 7505 7506 7507
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);

7508
void perf_tp_event(u16 event_type, u64 count, void *record, int entry_size,
7509 7510
		   struct pt_regs *regs, struct hlist_head *head, int rctx,
		   struct task_struct *task)
7511 7512
{
	struct perf_sample_data data;
7513 7514
	struct perf_event *event;

7515
	struct perf_raw_record raw = {
7516 7517 7518 7519
		.frag = {
			.size = entry_size,
			.data = record,
		},
7520 7521
	};

7522
	perf_sample_data_init(&data, 0, 0);
7523 7524
	data.raw = &raw;

7525 7526
	perf_trace_buf_update(record, event_type);

7527
	hlist_for_each_entry_rcu(event, head, hlist_entry) {
7528
		if (perf_tp_event_match(event, &data, regs))
7529
			perf_swevent_event(event, count, &data, regs);
7530
	}
7531

7532 7533 7534 7535 7536 7537 7538 7539 7540 7541 7542 7543 7544 7545 7546 7547 7548 7549 7550 7551 7552 7553 7554 7555 7556
	/*
	 * 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();
	}

7557
	perf_swevent_put_recursion_context(rctx);
7558 7559 7560
}
EXPORT_SYMBOL_GPL(perf_tp_event);

7561
static void tp_perf_event_destroy(struct perf_event *event)
7562
{
7563
	perf_trace_destroy(event);
7564 7565
}

7566
static int perf_tp_event_init(struct perf_event *event)
7567
{
7568 7569
	int err;

7570 7571 7572
	if (event->attr.type != PERF_TYPE_TRACEPOINT)
		return -ENOENT;

7573 7574 7575 7576 7577 7578
	/*
	 * no branch sampling for tracepoint events
	 */
	if (has_branch_stack(event))
		return -EOPNOTSUPP;

7579 7580
	err = perf_trace_init(event);
	if (err)
7581
		return err;
7582

7583
	event->destroy = tp_perf_event_destroy;
7584

7585 7586 7587 7588
	return 0;
}

static struct pmu perf_tracepoint = {
7589 7590
	.task_ctx_nr	= perf_sw_context,

7591
	.event_init	= perf_tp_event_init,
P
Peter Zijlstra 已提交
7592 7593 7594 7595
	.add		= perf_trace_add,
	.del		= perf_trace_del,
	.start		= perf_swevent_start,
	.stop		= perf_swevent_stop,
7596 7597 7598 7599 7600
	.read		= perf_swevent_read,
};

static inline void perf_tp_register(void)
{
P
Peter Zijlstra 已提交
7601
	perf_pmu_register(&perf_tracepoint, "tracepoint", PERF_TYPE_TRACEPOINT);
7602
}
L
Li Zefan 已提交
7603 7604 7605 7606 7607 7608

static void perf_event_free_filter(struct perf_event *event)
{
	ftrace_profile_free_filter(event);
}

7609 7610
static int perf_event_set_bpf_prog(struct perf_event *event, u32 prog_fd)
{
7611
	bool is_kprobe, is_tracepoint;
7612 7613 7614 7615 7616 7617 7618 7619
	struct bpf_prog *prog;

	if (event->attr.type != PERF_TYPE_TRACEPOINT)
		return -EINVAL;

	if (event->tp_event->prog)
		return -EEXIST;

7620 7621 7622 7623
	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 */
7624 7625 7626 7627 7628 7629
		return -EINVAL;

	prog = bpf_prog_get(prog_fd);
	if (IS_ERR(prog))
		return PTR_ERR(prog);

7630 7631
	if ((is_kprobe && prog->type != BPF_PROG_TYPE_KPROBE) ||
	    (is_tracepoint && prog->type != BPF_PROG_TYPE_TRACEPOINT)) {
7632 7633 7634 7635 7636
		/* valid fd, but invalid bpf program type */
		bpf_prog_put(prog);
		return -EINVAL;
	}

7637 7638 7639 7640 7641 7642 7643 7644
	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;
		}
	}
7645 7646 7647 7648 7649 7650 7651 7652 7653 7654 7655 7656 7657 7658 7659
	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;
7660
		bpf_prog_put(prog);
7661 7662 7663
	}
}

7664
#else
L
Li Zefan 已提交
7665

7666
static inline void perf_tp_register(void)
7667 7668
{
}
L
Li Zefan 已提交
7669 7670 7671 7672 7673

static void perf_event_free_filter(struct perf_event *event)
{
}

7674 7675 7676 7677 7678 7679 7680 7681
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)
{
}
7682
#endif /* CONFIG_EVENT_TRACING */
7683

7684
#ifdef CONFIG_HAVE_HW_BREAKPOINT
7685
void perf_bp_event(struct perf_event *bp, void *data)
7686
{
7687 7688 7689
	struct perf_sample_data sample;
	struct pt_regs *regs = data;

7690
	perf_sample_data_init(&sample, bp->attr.bp_addr, 0);
7691

P
Peter Zijlstra 已提交
7692
	if (!bp->hw.state && !perf_exclude_event(bp, regs))
7693
		perf_swevent_event(bp, 1, &sample, regs);
7694 7695 7696
}
#endif

7697 7698 7699 7700 7701 7702 7703 7704 7705 7706 7707 7708 7709 7710 7711 7712 7713 7714 7715 7716 7717 7718 7719 7720 7721 7722 7723 7724 7725 7726 7727 7728 7729 7730 7731 7732 7733 7734 7735 7736 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 7852 7853 7854 7855 7856 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 7987 7988 7989 7990 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
/*
 * 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;

		if (perf_addr_filter_needs_mmap(filter))
			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;
			}

			if (token == IF_SRC_FILE) {
				filename = match_strdup(&args[2]);
				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;
}

8053 8054 8055 8056 8057
static int perf_event_set_filter(struct perf_event *event, void __user *arg)
{
	char *filter_str;
	int ret = -EINVAL;

8058 8059 8060
	if ((event->attr.type != PERF_TYPE_TRACEPOINT ||
	    !IS_ENABLED(CONFIG_EVENT_TRACING)) &&
	    !has_addr_filter(event))
8061 8062 8063 8064 8065 8066 8067 8068 8069 8070
		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);
8071 8072
	else if (has_addr_filter(event))
		ret = perf_event_set_addr_filter(event, filter_str);
8073 8074 8075 8076 8077

	kfree(filter_str);
	return ret;
}

8078 8079 8080
/*
 * hrtimer based swevent callback
 */
8081

8082
static enum hrtimer_restart perf_swevent_hrtimer(struct hrtimer *hrtimer)
8083
{
8084 8085 8086 8087 8088
	enum hrtimer_restart ret = HRTIMER_RESTART;
	struct perf_sample_data data;
	struct pt_regs *regs;
	struct perf_event *event;
	u64 period;
8089

8090
	event = container_of(hrtimer, struct perf_event, hw.hrtimer);
P
Peter Zijlstra 已提交
8091 8092 8093 8094

	if (event->state != PERF_EVENT_STATE_ACTIVE)
		return HRTIMER_NORESTART;

8095
	event->pmu->read(event);
8096

8097
	perf_sample_data_init(&data, 0, event->hw.last_period);
8098 8099 8100
	regs = get_irq_regs();

	if (regs && !perf_exclude_event(event, regs)) {
8101
		if (!(event->attr.exclude_idle && is_idle_task(current)))
8102
			if (__perf_event_overflow(event, 1, &data, regs))
8103 8104
				ret = HRTIMER_NORESTART;
	}
8105

8106 8107
	period = max_t(u64, 10000, event->hw.sample_period);
	hrtimer_forward_now(hrtimer, ns_to_ktime(period));
8108

8109
	return ret;
8110 8111
}

8112
static void perf_swevent_start_hrtimer(struct perf_event *event)
8113
{
8114
	struct hw_perf_event *hwc = &event->hw;
8115 8116 8117 8118
	s64 period;

	if (!is_sampling_event(event))
		return;
8119

8120 8121 8122 8123
	period = local64_read(&hwc->period_left);
	if (period) {
		if (period < 0)
			period = 10000;
P
Peter Zijlstra 已提交
8124

8125 8126 8127 8128
		local64_set(&hwc->period_left, 0);
	} else {
		period = max_t(u64, 10000, hwc->sample_period);
	}
8129 8130
	hrtimer_start(&hwc->hrtimer, ns_to_ktime(period),
		      HRTIMER_MODE_REL_PINNED);
8131
}
8132 8133

static void perf_swevent_cancel_hrtimer(struct perf_event *event)
8134
{
8135 8136
	struct hw_perf_event *hwc = &event->hw;

8137
	if (is_sampling_event(event)) {
8138
		ktime_t remaining = hrtimer_get_remaining(&hwc->hrtimer);
P
Peter Zijlstra 已提交
8139
		local64_set(&hwc->period_left, ktime_to_ns(remaining));
8140 8141 8142

		hrtimer_cancel(&hwc->hrtimer);
	}
8143 8144
}

P
Peter Zijlstra 已提交
8145 8146 8147 8148 8149 8150 8151 8152 8153 8154 8155 8156 8157 8158 8159 8160 8161 8162 8163 8164
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);
8165
		hwc->last_period = hwc->sample_period;
P
Peter Zijlstra 已提交
8166 8167 8168 8169
		event->attr.freq = 0;
	}
}

8170 8171 8172 8173 8174
/*
 * Software event: cpu wall time clock
 */

static void cpu_clock_event_update(struct perf_event *event)
8175
{
8176 8177 8178
	s64 prev;
	u64 now;

P
Peter Zijlstra 已提交
8179
	now = local_clock();
8180 8181
	prev = local64_xchg(&event->hw.prev_count, now);
	local64_add(now - prev, &event->count);
8182 8183
}

P
Peter Zijlstra 已提交
8184
static void cpu_clock_event_start(struct perf_event *event, int flags)
8185
{
P
Peter Zijlstra 已提交
8186
	local64_set(&event->hw.prev_count, local_clock());
8187 8188 8189
	perf_swevent_start_hrtimer(event);
}

P
Peter Zijlstra 已提交
8190
static void cpu_clock_event_stop(struct perf_event *event, int flags)
8191
{
8192 8193 8194
	perf_swevent_cancel_hrtimer(event);
	cpu_clock_event_update(event);
}
8195

P
Peter Zijlstra 已提交
8196 8197 8198 8199
static int cpu_clock_event_add(struct perf_event *event, int flags)
{
	if (flags & PERF_EF_START)
		cpu_clock_event_start(event, flags);
8200
	perf_event_update_userpage(event);
P
Peter Zijlstra 已提交
8201 8202 8203 8204 8205 8206 8207 8208 8209

	return 0;
}

static void cpu_clock_event_del(struct perf_event *event, int flags)
{
	cpu_clock_event_stop(event, flags);
}

8210 8211 8212 8213
static void cpu_clock_event_read(struct perf_event *event)
{
	cpu_clock_event_update(event);
}
8214

8215 8216 8217 8218 8219 8220 8221 8222
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;

8223 8224 8225 8226 8227 8228
	/*
	 * no branch sampling for software events
	 */
	if (has_branch_stack(event))
		return -EOPNOTSUPP;

P
Peter Zijlstra 已提交
8229 8230
	perf_swevent_init_hrtimer(event);

8231
	return 0;
8232 8233
}

8234
static struct pmu perf_cpu_clock = {
8235 8236
	.task_ctx_nr	= perf_sw_context,

8237 8238
	.capabilities	= PERF_PMU_CAP_NO_NMI,

8239
	.event_init	= cpu_clock_event_init,
P
Peter Zijlstra 已提交
8240 8241 8242 8243
	.add		= cpu_clock_event_add,
	.del		= cpu_clock_event_del,
	.start		= cpu_clock_event_start,
	.stop		= cpu_clock_event_stop,
8244 8245 8246 8247 8248 8249 8250 8251
	.read		= cpu_clock_event_read,
};

/*
 * Software event: task time clock
 */

static void task_clock_event_update(struct perf_event *event, u64 now)
8252
{
8253 8254
	u64 prev;
	s64 delta;
8255

8256 8257 8258 8259
	prev = local64_xchg(&event->hw.prev_count, now);
	delta = now - prev;
	local64_add(delta, &event->count);
}
8260

P
Peter Zijlstra 已提交
8261
static void task_clock_event_start(struct perf_event *event, int flags)
8262
{
P
Peter Zijlstra 已提交
8263
	local64_set(&event->hw.prev_count, event->ctx->time);
8264 8265 8266
	perf_swevent_start_hrtimer(event);
}

P
Peter Zijlstra 已提交
8267
static void task_clock_event_stop(struct perf_event *event, int flags)
8268 8269 8270
{
	perf_swevent_cancel_hrtimer(event);
	task_clock_event_update(event, event->ctx->time);
P
Peter Zijlstra 已提交
8271 8272 8273 8274 8275 8276
}

static int task_clock_event_add(struct perf_event *event, int flags)
{
	if (flags & PERF_EF_START)
		task_clock_event_start(event, flags);
8277
	perf_event_update_userpage(event);
8278

P
Peter Zijlstra 已提交
8279 8280 8281 8282 8283 8284
	return 0;
}

static void task_clock_event_del(struct perf_event *event, int flags)
{
	task_clock_event_stop(event, PERF_EF_UPDATE);
8285 8286 8287 8288
}

static void task_clock_event_read(struct perf_event *event)
{
8289 8290 8291
	u64 now = perf_clock();
	u64 delta = now - event->ctx->timestamp;
	u64 time = event->ctx->time + delta;
8292 8293 8294 8295 8296

	task_clock_event_update(event, time);
}

static int task_clock_event_init(struct perf_event *event)
L
Li Zefan 已提交
8297
{
8298 8299 8300 8301 8302 8303
	if (event->attr.type != PERF_TYPE_SOFTWARE)
		return -ENOENT;

	if (event->attr.config != PERF_COUNT_SW_TASK_CLOCK)
		return -ENOENT;

8304 8305 8306 8307 8308 8309
	/*
	 * no branch sampling for software events
	 */
	if (has_branch_stack(event))
		return -EOPNOTSUPP;

P
Peter Zijlstra 已提交
8310 8311
	perf_swevent_init_hrtimer(event);

8312
	return 0;
L
Li Zefan 已提交
8313 8314
}

8315
static struct pmu perf_task_clock = {
8316 8317
	.task_ctx_nr	= perf_sw_context,

8318 8319
	.capabilities	= PERF_PMU_CAP_NO_NMI,

8320
	.event_init	= task_clock_event_init,
P
Peter Zijlstra 已提交
8321 8322 8323 8324
	.add		= task_clock_event_add,
	.del		= task_clock_event_del,
	.start		= task_clock_event_start,
	.stop		= task_clock_event_stop,
8325 8326
	.read		= task_clock_event_read,
};
L
Li Zefan 已提交
8327

P
Peter Zijlstra 已提交
8328
static void perf_pmu_nop_void(struct pmu *pmu)
8329 8330
{
}
L
Li Zefan 已提交
8331

8332 8333 8334 8335
static void perf_pmu_nop_txn(struct pmu *pmu, unsigned int flags)
{
}

P
Peter Zijlstra 已提交
8336
static int perf_pmu_nop_int(struct pmu *pmu)
L
Li Zefan 已提交
8337
{
P
Peter Zijlstra 已提交
8338
	return 0;
L
Li Zefan 已提交
8339 8340
}

8341
static DEFINE_PER_CPU(unsigned int, nop_txn_flags);
8342 8343

static void perf_pmu_start_txn(struct pmu *pmu, unsigned int flags)
L
Li Zefan 已提交
8344
{
8345 8346 8347 8348 8349
	__this_cpu_write(nop_txn_flags, flags);

	if (flags & ~PERF_PMU_TXN_ADD)
		return;

P
Peter Zijlstra 已提交
8350
	perf_pmu_disable(pmu);
L
Li Zefan 已提交
8351 8352
}

P
Peter Zijlstra 已提交
8353 8354
static int perf_pmu_commit_txn(struct pmu *pmu)
{
8355 8356 8357 8358 8359 8360 8361
	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
8362 8363 8364
	perf_pmu_enable(pmu);
	return 0;
}
8365

P
Peter Zijlstra 已提交
8366
static void perf_pmu_cancel_txn(struct pmu *pmu)
8367
{
8368 8369 8370 8371 8372 8373 8374
	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
8375
	perf_pmu_enable(pmu);
8376 8377
}

8378 8379
static int perf_event_idx_default(struct perf_event *event)
{
8380
	return 0;
8381 8382
}

P
Peter Zijlstra 已提交
8383 8384 8385 8386
/*
 * Ensures all contexts with the same task_ctx_nr have the same
 * pmu_cpu_context too.
 */
8387
static struct perf_cpu_context __percpu *find_pmu_context(int ctxn)
8388
{
P
Peter Zijlstra 已提交
8389
	struct pmu *pmu;
8390

P
Peter Zijlstra 已提交
8391 8392
	if (ctxn < 0)
		return NULL;
8393

P
Peter Zijlstra 已提交
8394 8395 8396 8397
	list_for_each_entry(pmu, &pmus, entry) {
		if (pmu->task_ctx_nr == ctxn)
			return pmu->pmu_cpu_context;
	}
8398

P
Peter Zijlstra 已提交
8399
	return NULL;
8400 8401
}

8402
static void update_pmu_context(struct pmu *pmu, struct pmu *old_pmu)
8403
{
8404 8405 8406 8407 8408 8409 8410
	int cpu;

	for_each_possible_cpu(cpu) {
		struct perf_cpu_context *cpuctx;

		cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);

8411 8412
		if (cpuctx->unique_pmu == old_pmu)
			cpuctx->unique_pmu = pmu;
8413 8414 8415 8416 8417 8418
	}
}

static void free_pmu_context(struct pmu *pmu)
{
	struct pmu *i;
8419

P
Peter Zijlstra 已提交
8420
	mutex_lock(&pmus_lock);
8421
	/*
P
Peter Zijlstra 已提交
8422
	 * Like a real lame refcount.
8423
	 */
8424 8425 8426
	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
8427
			goto out;
8428
		}
P
Peter Zijlstra 已提交
8429
	}
8430

8431
	free_percpu(pmu->pmu_cpu_context);
P
Peter Zijlstra 已提交
8432 8433
out:
	mutex_unlock(&pmus_lock);
8434
}
8435 8436 8437 8438 8439 8440 8441 8442 8443 8444 8445 8446 8447 8448

/*
 * 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
8449
static struct idr pmu_idr;
8450

P
Peter Zijlstra 已提交
8451 8452 8453 8454 8455 8456 8457
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);
}
8458
static DEVICE_ATTR_RO(type);
P
Peter Zijlstra 已提交
8459

8460 8461 8462 8463 8464 8465 8466 8467 8468 8469
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);
}

8470 8471
static DEFINE_MUTEX(mux_interval_mutex);

8472 8473 8474 8475 8476 8477 8478 8479 8480 8481 8482 8483 8484 8485 8486 8487 8488 8489 8490
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;

8491
	mutex_lock(&mux_interval_mutex);
8492 8493 8494
	pmu->hrtimer_interval_ms = timer;

	/* update all cpuctx for this PMU */
8495 8496
	get_online_cpus();
	for_each_online_cpu(cpu) {
8497 8498 8499 8500
		struct perf_cpu_context *cpuctx;
		cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
		cpuctx->hrtimer_interval = ns_to_ktime(NSEC_PER_MSEC * timer);

8501 8502
		cpu_function_call(cpu,
			(remote_function_f)perf_mux_hrtimer_restart, cpuctx);
8503
	}
8504 8505
	put_online_cpus();
	mutex_unlock(&mux_interval_mutex);
8506 8507 8508

	return count;
}
8509
static DEVICE_ATTR_RW(perf_event_mux_interval_ms);
8510

8511 8512 8513 8514
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
8515
};
8516
ATTRIBUTE_GROUPS(pmu_dev);
P
Peter Zijlstra 已提交
8517 8518 8519 8520

static int pmu_bus_running;
static struct bus_type pmu_bus = {
	.name		= "event_source",
8521
	.dev_groups	= pmu_dev_groups,
P
Peter Zijlstra 已提交
8522 8523 8524 8525 8526 8527 8528 8529 8530 8531 8532 8533 8534 8535 8536
};

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;

8537
	pmu->dev->groups = pmu->attr_groups;
P
Peter Zijlstra 已提交
8538 8539 8540 8541 8542 8543 8544 8545 8546 8547 8548 8549
	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;

8550 8551 8552 8553 8554 8555 8556
	/* 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
8557 8558 8559
out:
	return ret;

8560 8561 8562
del_dev:
	device_del(pmu->dev);

P
Peter Zijlstra 已提交
8563 8564 8565 8566 8567
free_dev:
	put_device(pmu->dev);
	goto out;
}

8568
static struct lock_class_key cpuctx_mutex;
8569
static struct lock_class_key cpuctx_lock;
8570

8571
int perf_pmu_register(struct pmu *pmu, const char *name, int type)
8572
{
P
Peter Zijlstra 已提交
8573
	int cpu, ret;
8574

8575
	mutex_lock(&pmus_lock);
P
Peter Zijlstra 已提交
8576 8577 8578 8579
	ret = -ENOMEM;
	pmu->pmu_disable_count = alloc_percpu(int);
	if (!pmu->pmu_disable_count)
		goto unlock;
8580

P
Peter Zijlstra 已提交
8581 8582 8583 8584 8585 8586
	pmu->type = -1;
	if (!name)
		goto skip_type;
	pmu->name = name;

	if (type < 0) {
T
Tejun Heo 已提交
8587 8588 8589
		type = idr_alloc(&pmu_idr, pmu, PERF_TYPE_MAX, 0, GFP_KERNEL);
		if (type < 0) {
			ret = type;
P
Peter Zijlstra 已提交
8590 8591 8592 8593 8594
			goto free_pdc;
		}
	}
	pmu->type = type;

P
Peter Zijlstra 已提交
8595 8596 8597 8598 8599 8600
	if (pmu_bus_running) {
		ret = pmu_dev_alloc(pmu);
		if (ret)
			goto free_idr;
	}

P
Peter Zijlstra 已提交
8601
skip_type:
8602 8603 8604
	if (pmu->task_ctx_nr == perf_hw_context) {
		static int hw_context_taken = 0;

8605 8606 8607 8608 8609 8610 8611
		/*
		 * 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)))
8612 8613 8614 8615 8616
			pmu->task_ctx_nr = perf_invalid_context;

		hw_context_taken = 1;
	}

P
Peter Zijlstra 已提交
8617 8618 8619
	pmu->pmu_cpu_context = find_pmu_context(pmu->task_ctx_nr);
	if (pmu->pmu_cpu_context)
		goto got_cpu_context;
8620

W
Wei Yongjun 已提交
8621
	ret = -ENOMEM;
P
Peter Zijlstra 已提交
8622 8623
	pmu->pmu_cpu_context = alloc_percpu(struct perf_cpu_context);
	if (!pmu->pmu_cpu_context)
P
Peter Zijlstra 已提交
8624
		goto free_dev;
8625

P
Peter Zijlstra 已提交
8626 8627 8628 8629
	for_each_possible_cpu(cpu) {
		struct perf_cpu_context *cpuctx;

		cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
8630
		__perf_event_init_context(&cpuctx->ctx);
8631
		lockdep_set_class(&cpuctx->ctx.mutex, &cpuctx_mutex);
8632
		lockdep_set_class(&cpuctx->ctx.lock, &cpuctx_lock);
P
Peter Zijlstra 已提交
8633
		cpuctx->ctx.pmu = pmu;
8634

8635
		__perf_mux_hrtimer_init(cpuctx, cpu);
8636

8637
		cpuctx->unique_pmu = pmu;
P
Peter Zijlstra 已提交
8638
	}
8639

P
Peter Zijlstra 已提交
8640
got_cpu_context:
P
Peter Zijlstra 已提交
8641 8642 8643 8644 8645 8646 8647 8648 8649 8650 8651
	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 {
8652
			pmu->start_txn  = perf_pmu_nop_txn;
P
Peter Zijlstra 已提交
8653 8654
			pmu->commit_txn = perf_pmu_nop_int;
			pmu->cancel_txn = perf_pmu_nop_void;
8655
		}
8656
	}
8657

P
Peter Zijlstra 已提交
8658 8659 8660 8661 8662
	if (!pmu->pmu_enable) {
		pmu->pmu_enable  = perf_pmu_nop_void;
		pmu->pmu_disable = perf_pmu_nop_void;
	}

8663 8664 8665
	if (!pmu->event_idx)
		pmu->event_idx = perf_event_idx_default;

8666
	list_add_rcu(&pmu->entry, &pmus);
8667
	atomic_set(&pmu->exclusive_cnt, 0);
P
Peter Zijlstra 已提交
8668 8669
	ret = 0;
unlock:
8670 8671
	mutex_unlock(&pmus_lock);

P
Peter Zijlstra 已提交
8672
	return ret;
P
Peter Zijlstra 已提交
8673

P
Peter Zijlstra 已提交
8674 8675 8676 8677
free_dev:
	device_del(pmu->dev);
	put_device(pmu->dev);

P
Peter Zijlstra 已提交
8678 8679 8680 8681
free_idr:
	if (pmu->type >= PERF_TYPE_MAX)
		idr_remove(&pmu_idr, pmu->type);

P
Peter Zijlstra 已提交
8682 8683 8684
free_pdc:
	free_percpu(pmu->pmu_disable_count);
	goto unlock;
8685
}
8686
EXPORT_SYMBOL_GPL(perf_pmu_register);
8687

8688
void perf_pmu_unregister(struct pmu *pmu)
8689
{
8690 8691 8692
	mutex_lock(&pmus_lock);
	list_del_rcu(&pmu->entry);
	mutex_unlock(&pmus_lock);
8693

8694
	/*
P
Peter Zijlstra 已提交
8695 8696
	 * We dereference the pmu list under both SRCU and regular RCU, so
	 * synchronize against both of those.
8697
	 */
8698
	synchronize_srcu(&pmus_srcu);
P
Peter Zijlstra 已提交
8699
	synchronize_rcu();
8700

P
Peter Zijlstra 已提交
8701
	free_percpu(pmu->pmu_disable_count);
P
Peter Zijlstra 已提交
8702 8703
	if (pmu->type >= PERF_TYPE_MAX)
		idr_remove(&pmu_idr, pmu->type);
8704 8705
	if (pmu->nr_addr_filters)
		device_remove_file(pmu->dev, &dev_attr_nr_addr_filters);
P
Peter Zijlstra 已提交
8706 8707
	device_del(pmu->dev);
	put_device(pmu->dev);
8708
	free_pmu_context(pmu);
8709
}
8710
EXPORT_SYMBOL_GPL(perf_pmu_unregister);
8711

8712 8713
static int perf_try_init_event(struct pmu *pmu, struct perf_event *event)
{
P
Peter Zijlstra 已提交
8714
	struct perf_event_context *ctx = NULL;
8715 8716 8717 8718
	int ret;

	if (!try_module_get(pmu->module))
		return -ENODEV;
P
Peter Zijlstra 已提交
8719 8720

	if (event->group_leader != event) {
8721 8722 8723 8724 8725 8726
		/*
		 * 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
8727 8728 8729
		BUG_ON(!ctx);
	}

8730 8731
	event->pmu = pmu;
	ret = pmu->event_init(event);
P
Peter Zijlstra 已提交
8732 8733 8734 8735

	if (ctx)
		perf_event_ctx_unlock(event->group_leader, ctx);

8736 8737 8738 8739 8740 8741
	if (ret)
		module_put(pmu->module);

	return ret;
}

8742
static struct pmu *perf_init_event(struct perf_event *event)
8743 8744 8745
{
	struct pmu *pmu = NULL;
	int idx;
8746
	int ret;
8747 8748

	idx = srcu_read_lock(&pmus_srcu);
P
Peter Zijlstra 已提交
8749 8750 8751 8752

	rcu_read_lock();
	pmu = idr_find(&pmu_idr, event->attr.type);
	rcu_read_unlock();
8753
	if (pmu) {
8754
		ret = perf_try_init_event(pmu, event);
8755 8756
		if (ret)
			pmu = ERR_PTR(ret);
P
Peter Zijlstra 已提交
8757
		goto unlock;
8758
	}
P
Peter Zijlstra 已提交
8759

8760
	list_for_each_entry_rcu(pmu, &pmus, entry) {
8761
		ret = perf_try_init_event(pmu, event);
8762
		if (!ret)
P
Peter Zijlstra 已提交
8763
			goto unlock;
8764

8765 8766
		if (ret != -ENOENT) {
			pmu = ERR_PTR(ret);
P
Peter Zijlstra 已提交
8767
			goto unlock;
8768
		}
8769
	}
P
Peter Zijlstra 已提交
8770 8771
	pmu = ERR_PTR(-ENOENT);
unlock:
8772
	srcu_read_unlock(&pmus_srcu, idx);
8773

8774
	return pmu;
8775 8776
}

8777 8778 8779 8780 8781 8782 8783 8784 8785
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);
}

8786 8787 8788 8789 8790 8791 8792
/*
 * 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.
 */
8793 8794
static void account_pmu_sb_event(struct perf_event *event)
{
8795
	if (is_sb_event(event))
8796 8797 8798
		attach_sb_event(event);
}

8799 8800 8801 8802 8803 8804 8805 8806 8807
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));
}

8808 8809 8810 8811 8812 8813 8814 8815 8816 8817 8818 8819 8820 8821 8822 8823 8824 8825 8826 8827 8828
/* 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);
}


8829 8830
static void account_event(struct perf_event *event)
{
8831 8832
	bool inc = false;

8833 8834 8835
	if (event->parent)
		return;

8836
	if (event->attach_state & PERF_ATTACH_TASK)
8837
		inc = true;
8838 8839 8840 8841 8842 8843
	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);
8844 8845
	if (event->attr.freq)
		account_freq_event();
8846 8847
	if (event->attr.context_switch) {
		atomic_inc(&nr_switch_events);
8848
		inc = true;
8849
	}
8850
	if (has_branch_stack(event))
8851
		inc = true;
8852
	if (is_cgroup_event(event))
8853 8854
		inc = true;

8855 8856 8857 8858 8859 8860 8861 8862 8863 8864 8865 8866 8867 8868 8869 8870 8871 8872 8873 8874 8875 8876
	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:
8877 8878

	account_event_cpu(event, event->cpu);
8879 8880

	account_pmu_sb_event(event);
8881 8882
}

T
Thomas Gleixner 已提交
8883
/*
8884
 * Allocate and initialize a event structure
T
Thomas Gleixner 已提交
8885
 */
8886
static struct perf_event *
8887
perf_event_alloc(struct perf_event_attr *attr, int cpu,
8888 8889 8890
		 struct task_struct *task,
		 struct perf_event *group_leader,
		 struct perf_event *parent_event,
8891
		 perf_overflow_handler_t overflow_handler,
8892
		 void *context, int cgroup_fd)
T
Thomas Gleixner 已提交
8893
{
P
Peter Zijlstra 已提交
8894
	struct pmu *pmu;
8895 8896
	struct perf_event *event;
	struct hw_perf_event *hwc;
8897
	long err = -EINVAL;
T
Thomas Gleixner 已提交
8898

8899 8900 8901 8902 8903
	if ((unsigned)cpu >= nr_cpu_ids) {
		if (!task || cpu != -1)
			return ERR_PTR(-EINVAL);
	}

8904
	event = kzalloc(sizeof(*event), GFP_KERNEL);
8905
	if (!event)
8906
		return ERR_PTR(-ENOMEM);
T
Thomas Gleixner 已提交
8907

8908
	/*
8909
	 * Single events are their own group leaders, with an
8910 8911 8912
	 * empty sibling list:
	 */
	if (!group_leader)
8913
		group_leader = event;
8914

8915 8916
	mutex_init(&event->child_mutex);
	INIT_LIST_HEAD(&event->child_list);
8917

8918 8919 8920
	INIT_LIST_HEAD(&event->group_entry);
	INIT_LIST_HEAD(&event->event_entry);
	INIT_LIST_HEAD(&event->sibling_list);
8921
	INIT_LIST_HEAD(&event->rb_entry);
8922
	INIT_LIST_HEAD(&event->active_entry);
8923
	INIT_LIST_HEAD(&event->addr_filters.list);
8924 8925
	INIT_HLIST_NODE(&event->hlist_entry);

8926

8927
	init_waitqueue_head(&event->waitq);
8928
	init_irq_work(&event->pending, perf_pending_event);
T
Thomas Gleixner 已提交
8929

8930
	mutex_init(&event->mmap_mutex);
8931
	raw_spin_lock_init(&event->addr_filters.lock);
8932

8933
	atomic_long_set(&event->refcount, 1);
8934 8935 8936 8937 8938
	event->cpu		= cpu;
	event->attr		= *attr;
	event->group_leader	= group_leader;
	event->pmu		= NULL;
	event->oncpu		= -1;
8939

8940
	event->parent		= parent_event;
8941

8942
	event->ns		= get_pid_ns(task_active_pid_ns(current));
8943
	event->id		= atomic64_inc_return(&perf_event_id);
8944

8945
	event->state		= PERF_EVENT_STATE_INACTIVE;
8946

8947 8948 8949
	if (task) {
		event->attach_state = PERF_ATTACH_TASK;
		/*
8950 8951 8952
		 * 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.
8953
		 */
8954
		event->hw.target = task;
8955 8956
	}

8957 8958 8959 8960
	event->clock = &local_clock;
	if (parent_event)
		event->clock = parent_event->clock;

8961
	if (!overflow_handler && parent_event) {
8962
		overflow_handler = parent_event->overflow_handler;
8963 8964
		context = parent_event->overflow_handler_context;
	}
8965

8966 8967 8968
	if (overflow_handler) {
		event->overflow_handler	= overflow_handler;
		event->overflow_handler_context = context;
8969 8970 8971
	} else if (is_write_backward(event)){
		event->overflow_handler = perf_event_output_backward;
		event->overflow_handler_context = NULL;
8972
	} else {
8973
		event->overflow_handler = perf_event_output_forward;
8974 8975
		event->overflow_handler_context = NULL;
	}
8976

J
Jiri Olsa 已提交
8977
	perf_event__state_init(event);
8978

8979
	pmu = NULL;
8980

8981
	hwc = &event->hw;
8982
	hwc->sample_period = attr->sample_period;
8983
	if (attr->freq && attr->sample_freq)
8984
		hwc->sample_period = 1;
8985
	hwc->last_period = hwc->sample_period;
8986

8987
	local64_set(&hwc->period_left, hwc->sample_period);
8988

8989
	/*
8990
	 * we currently do not support PERF_FORMAT_GROUP on inherited events
8991
	 */
8992
	if (attr->inherit && (attr->read_format & PERF_FORMAT_GROUP))
8993
		goto err_ns;
8994 8995 8996

	if (!has_branch_stack(event))
		event->attr.branch_sample_type = 0;
8997

8998 8999 9000 9001 9002 9003
	if (cgroup_fd != -1) {
		err = perf_cgroup_connect(cgroup_fd, event, attr, group_leader);
		if (err)
			goto err_ns;
	}

9004
	pmu = perf_init_event(event);
9005
	if (!pmu)
9006 9007
		goto err_ns;
	else if (IS_ERR(pmu)) {
9008
		err = PTR_ERR(pmu);
9009
		goto err_ns;
I
Ingo Molnar 已提交
9010
	}
9011

9012 9013 9014 9015
	err = exclusive_event_init(event);
	if (err)
		goto err_pmu;

9016 9017 9018 9019 9020 9021 9022 9023 9024 9025 9026
	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;
	}

9027
	if (!event->parent) {
9028
		if (event->attr.sample_type & PERF_SAMPLE_CALLCHAIN) {
9029
			err = get_callchain_buffers(attr->sample_max_stack);
9030
			if (err)
9031
				goto err_addr_filters;
9032
		}
9033
	}
9034

9035 9036 9037
	/* symmetric to unaccount_event() in _free_event() */
	account_event(event);

9038
	return event;
9039

9040 9041 9042
err_addr_filters:
	kfree(event->addr_filters_offs);

9043 9044 9045
err_per_task:
	exclusive_event_destroy(event);

9046 9047 9048
err_pmu:
	if (event->destroy)
		event->destroy(event);
9049
	module_put(pmu->module);
9050
err_ns:
9051 9052
	if (is_cgroup_event(event))
		perf_detach_cgroup(event);
9053 9054 9055 9056 9057
	if (event->ns)
		put_pid_ns(event->ns);
	kfree(event);

	return ERR_PTR(err);
T
Thomas Gleixner 已提交
9058 9059
}

9060 9061
static int perf_copy_attr(struct perf_event_attr __user *uattr,
			  struct perf_event_attr *attr)
9062 9063
{
	u32 size;
9064
	int ret;
9065 9066 9067 9068 9069 9070 9071 9072 9073 9074 9075 9076 9077 9078 9079 9080 9081 9082 9083 9084 9085 9086 9087 9088

	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,
9089 9090 9091
	 * 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.
9092 9093
	 */
	if (size > sizeof(*attr)) {
9094 9095 9096
		unsigned char __user *addr;
		unsigned char __user *end;
		unsigned char val;
9097

9098 9099
		addr = (void __user *)uattr + sizeof(*attr);
		end  = (void __user *)uattr + size;
9100

9101
		for (; addr < end; addr++) {
9102 9103 9104 9105 9106 9107
			ret = get_user(val, addr);
			if (ret)
				return ret;
			if (val)
				goto err_size;
		}
9108
		size = sizeof(*attr);
9109 9110 9111 9112 9113 9114
	}

	ret = copy_from_user(attr, uattr, size);
	if (ret)
		return -EFAULT;

9115
	if (attr->__reserved_1)
9116 9117 9118 9119 9120 9121 9122 9123
		return -EINVAL;

	if (attr->sample_type & ~(PERF_SAMPLE_MAX-1))
		return -EINVAL;

	if (attr->read_format & ~(PERF_FORMAT_MAX-1))
		return -EINVAL;

9124 9125 9126 9127 9128 9129 9130 9131 9132 9133 9134 9135 9136 9137 9138 9139 9140 9141 9142 9143 9144 9145 9146 9147 9148 9149 9150 9151
	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;
		}
9152 9153
		/* privileged levels capture (kernel, hv): check permissions */
		if ((mask & PERF_SAMPLE_BRANCH_PERM_PLM)
9154 9155
		    && perf_paranoid_kernel() && !capable(CAP_SYS_ADMIN))
			return -EACCES;
9156
	}
9157

9158
	if (attr->sample_type & PERF_SAMPLE_REGS_USER) {
9159
		ret = perf_reg_validate(attr->sample_regs_user);
9160 9161 9162 9163 9164 9165 9166 9167 9168 9169 9170 9171 9172 9173 9174 9175 9176 9177
		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;
	}
9178

9179 9180
	if (attr->sample_type & PERF_SAMPLE_REGS_INTR)
		ret = perf_reg_validate(attr->sample_regs_intr);
9181 9182 9183 9184 9185 9186 9187 9188 9189
out:
	return ret;

err_size:
	put_user(sizeof(*attr), &uattr->size);
	ret = -E2BIG;
	goto out;
}

9190 9191
static int
perf_event_set_output(struct perf_event *event, struct perf_event *output_event)
9192
{
9193
	struct ring_buffer *rb = NULL;
9194 9195
	int ret = -EINVAL;

9196
	if (!output_event)
9197 9198
		goto set;

9199 9200
	/* don't allow circular references */
	if (event == output_event)
9201 9202
		goto out;

9203 9204 9205 9206 9207 9208 9209
	/*
	 * Don't allow cross-cpu buffers
	 */
	if (output_event->cpu != event->cpu)
		goto out;

	/*
9210
	 * If its not a per-cpu rb, it must be the same task.
9211 9212 9213 9214
	 */
	if (output_event->cpu == -1 && output_event->ctx != event->ctx)
		goto out;

9215 9216 9217 9218 9219 9220
	/*
	 * Mixing clocks in the same buffer is trouble you don't need.
	 */
	if (output_event->clock != event->clock)
		goto out;

9221 9222 9223 9224 9225 9226 9227
	/*
	 * 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;

9228 9229 9230 9231 9232 9233 9234
	/*
	 * 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;

9235
set:
9236
	mutex_lock(&event->mmap_mutex);
9237 9238 9239
	/* Can't redirect output if we've got an active mmap() */
	if (atomic_read(&event->mmap_count))
		goto unlock;
9240

9241
	if (output_event) {
9242 9243 9244
		/* get the rb we want to redirect to */
		rb = ring_buffer_get(output_event);
		if (!rb)
9245
			goto unlock;
9246 9247
	}

9248
	ring_buffer_attach(event, rb);
9249

9250
	ret = 0;
9251 9252 9253
unlock:
	mutex_unlock(&event->mmap_mutex);

9254 9255 9256 9257
out:
	return ret;
}

P
Peter Zijlstra 已提交
9258 9259 9260 9261 9262 9263 9264 9265 9266
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);
}

9267 9268 9269 9270 9271 9272 9273 9274 9275 9276 9277 9278 9279 9280 9281 9282 9283 9284 9285 9286 9287 9288 9289 9290 9291 9292 9293 9294 9295 9296 9297 9298 9299 9300 9301 9302 9303
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
9304
/**
9305
 * sys_perf_event_open - open a performance event, associate it to a task/cpu
I
Ingo Molnar 已提交
9306
 *
9307
 * @attr_uptr:	event_id type attributes for monitoring/sampling
T
Thomas Gleixner 已提交
9308
 * @pid:		target pid
I
Ingo Molnar 已提交
9309
 * @cpu:		target cpu
9310
 * @group_fd:		group leader event fd
T
Thomas Gleixner 已提交
9311
 */
9312 9313
SYSCALL_DEFINE5(perf_event_open,
		struct perf_event_attr __user *, attr_uptr,
9314
		pid_t, pid, int, cpu, int, group_fd, unsigned long, flags)
T
Thomas Gleixner 已提交
9315
{
9316 9317
	struct perf_event *group_leader = NULL, *output_event = NULL;
	struct perf_event *event, *sibling;
9318
	struct perf_event_attr attr;
P
Peter Zijlstra 已提交
9319
	struct perf_event_context *ctx, *uninitialized_var(gctx);
9320
	struct file *event_file = NULL;
9321
	struct fd group = {NULL, 0};
M
Matt Helsley 已提交
9322
	struct task_struct *task = NULL;
9323
	struct pmu *pmu;
9324
	int event_fd;
9325
	int move_group = 0;
9326
	int err;
9327
	int f_flags = O_RDWR;
9328
	int cgroup_fd = -1;
T
Thomas Gleixner 已提交
9329

9330
	/* for future expandability... */
S
Stephane Eranian 已提交
9331
	if (flags & ~PERF_FLAG_ALL)
9332 9333
		return -EINVAL;

9334 9335 9336
	err = perf_copy_attr(attr_uptr, &attr);
	if (err)
		return err;
9337

9338 9339 9340 9341 9342
	if (!attr.exclude_kernel) {
		if (perf_paranoid_kernel() && !capable(CAP_SYS_ADMIN))
			return -EACCES;
	}

9343
	if (attr.freq) {
9344
		if (attr.sample_freq > sysctl_perf_event_sample_rate)
9345
			return -EINVAL;
9346 9347 9348
	} else {
		if (attr.sample_period & (1ULL << 63))
			return -EINVAL;
9349 9350
	}

9351 9352 9353
	if (!attr.sample_max_stack)
		attr.sample_max_stack = sysctl_perf_event_max_stack;

S
Stephane Eranian 已提交
9354 9355 9356 9357 9358 9359 9360 9361 9362
	/*
	 * 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;

9363 9364 9365 9366
	if (flags & PERF_FLAG_FD_CLOEXEC)
		f_flags |= O_CLOEXEC;

	event_fd = get_unused_fd_flags(f_flags);
9367 9368 9369
	if (event_fd < 0)
		return event_fd;

9370
	if (group_fd != -1) {
9371 9372
		err = perf_fget_light(group_fd, &group);
		if (err)
9373
			goto err_fd;
9374
		group_leader = group.file->private_data;
9375 9376 9377 9378 9379 9380
		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
9381
	if (pid != -1 && !(flags & PERF_FLAG_PID_CGROUP)) {
9382 9383 9384 9385 9386 9387 9388
		task = find_lively_task_by_vpid(pid);
		if (IS_ERR(task)) {
			err = PTR_ERR(task);
			goto err_group_fd;
		}
	}

9389 9390 9391 9392 9393 9394
	if (task && group_leader &&
	    group_leader->attr.inherit != attr.inherit) {
		err = -EINVAL;
		goto err_task;
	}

9395 9396
	get_online_cpus();

9397 9398 9399 9400 9401 9402 9403 9404 9405 9406 9407 9408 9409 9410 9411 9412 9413 9414
	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;
	}

9415 9416 9417
	if (flags & PERF_FLAG_PID_CGROUP)
		cgroup_fd = pid;

9418
	event = perf_event_alloc(&attr, cpu, task, group_leader, NULL,
9419
				 NULL, NULL, cgroup_fd);
9420 9421
	if (IS_ERR(event)) {
		err = PTR_ERR(event);
9422
		goto err_cred;
9423 9424
	}

9425 9426
	if (is_sampling_event(event)) {
		if (event->pmu->capabilities & PERF_PMU_CAP_NO_INTERRUPT) {
9427
			err = -EOPNOTSUPP;
9428 9429 9430 9431
			goto err_alloc;
		}
	}

9432 9433 9434 9435 9436
	/*
	 * Special case software events and allow them to be part of
	 * any hardware group.
	 */
	pmu = event->pmu;
9437

9438 9439 9440 9441 9442 9443
	if (attr.use_clockid) {
		err = perf_event_set_clock(event, attr.clockid);
		if (err)
			goto err_alloc;
	}

9444 9445 9446 9447 9448 9449 9450 9451 9452 9453 9454 9455 9456 9457 9458 9459 9460 9461 9462 9463 9464 9465
	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) &&
			   (group_leader->group_flags & PERF_GROUP_SOFTWARE)) {
			/*
			 * 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;
		}
	}
9466 9467 9468 9469

	/*
	 * Get the target context (task or percpu):
	 */
9470
	ctx = find_get_context(pmu, task, event);
9471 9472
	if (IS_ERR(ctx)) {
		err = PTR_ERR(ctx);
9473
		goto err_alloc;
9474 9475
	}

9476 9477 9478 9479 9480
	if ((pmu->capabilities & PERF_PMU_CAP_EXCLUSIVE) && group_leader) {
		err = -EBUSY;
		goto err_context;
	}

I
Ingo Molnar 已提交
9481
	/*
9482
	 * Look up the group leader (we will attach this event to it):
9483
	 */
9484
	if (group_leader) {
9485
		err = -EINVAL;
9486 9487

		/*
I
Ingo Molnar 已提交
9488 9489 9490 9491
		 * Do not allow a recursive hierarchy (this new sibling
		 * becoming part of another group-sibling):
		 */
		if (group_leader->group_leader != group_leader)
9492
			goto err_context;
9493 9494 9495 9496 9497

		/* 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
9498 9499 9500
		/*
		 * Do not allow to attach to a group in a different
		 * task or CPU context:
9501
		 */
9502
		if (move_group) {
9503 9504 9505 9506 9507 9508 9509 9510 9511 9512 9513 9514 9515
			/*
			 * 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)
9516 9517 9518 9519 9520 9521
				goto err_context;
		} else {
			if (group_leader->ctx != ctx)
				goto err_context;
		}

9522 9523 9524
		/*
		 * Only a group leader can be exclusive or pinned
		 */
9525
		if (attr.exclusive || attr.pinned)
9526
			goto err_context;
9527 9528 9529 9530 9531
	}

	if (output_event) {
		err = perf_event_set_output(event, output_event);
		if (err)
9532
			goto err_context;
9533
	}
T
Thomas Gleixner 已提交
9534

9535 9536
	event_file = anon_inode_getfile("[perf_event]", &perf_fops, event,
					f_flags);
9537 9538
	if (IS_ERR(event_file)) {
		err = PTR_ERR(event_file);
9539
		event_file = NULL;
9540
		goto err_context;
9541
	}
9542

9543
	if (move_group) {
P
Peter Zijlstra 已提交
9544
		gctx = group_leader->ctx;
9545
		mutex_lock_double(&gctx->mutex, &ctx->mutex);
9546 9547 9548 9549
		if (gctx->task == TASK_TOMBSTONE) {
			err = -ESRCH;
			goto err_locked;
		}
9550 9551 9552 9553
	} else {
		mutex_lock(&ctx->mutex);
	}

9554 9555 9556 9557 9558
	if (ctx->task == TASK_TOMBSTONE) {
		err = -ESRCH;
		goto err_locked;
	}

P
Peter Zijlstra 已提交
9559 9560 9561 9562 9563
	if (!perf_event_validate_size(event)) {
		err = -E2BIG;
		goto err_locked;
	}

9564 9565 9566 9567 9568 9569 9570
	/*
	 * 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
9571

9572 9573 9574
		err = -EBUSY;
		goto err_locked;
	}
P
Peter Zijlstra 已提交
9575

9576 9577
	WARN_ON_ONCE(ctx->parent_ctx);

9578 9579 9580 9581 9582
	/*
	 * This is the point on no return; we cannot fail hereafter. This is
	 * where we start modifying current state.
	 */

9583
	if (move_group) {
P
Peter Zijlstra 已提交
9584 9585 9586 9587
		/*
		 * See perf_event_ctx_lock() for comments on the details
		 * of swizzling perf_event::ctx.
		 */
9588
		perf_remove_from_context(group_leader, 0);
J
Jiri Olsa 已提交
9589

9590 9591
		list_for_each_entry(sibling, &group_leader->sibling_list,
				    group_entry) {
9592
			perf_remove_from_context(sibling, 0);
9593 9594 9595
			put_ctx(gctx);
		}

P
Peter Zijlstra 已提交
9596 9597 9598 9599
		/*
		 * Wait for everybody to stop referencing the events through
		 * the old lists, before installing it on new lists.
		 */
9600
		synchronize_rcu();
P
Peter Zijlstra 已提交
9601

9602 9603 9604 9605 9606 9607 9608 9609 9610 9611
		/*
		 * 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.
		 */
9612 9613
		list_for_each_entry(sibling, &group_leader->sibling_list,
				    group_entry) {
9614
			perf_event__state_init(sibling);
9615
			perf_install_in_context(ctx, sibling, sibling->cpu);
9616 9617
			get_ctx(ctx);
		}
9618 9619 9620 9621 9622 9623 9624 9625 9626

		/*
		 * 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);
9627

9628 9629 9630 9631 9632 9633
		/*
		 * Now that all events are installed in @ctx, nothing
		 * references @gctx anymore, so drop the last reference we have
		 * on it.
		 */
		put_ctx(gctx);
9634 9635
	}

9636 9637 9638 9639 9640 9641 9642 9643 9644
	/*
	 * 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
9645 9646
	event->owner = current;

9647
	perf_install_in_context(ctx, event, event->cpu);
9648
	perf_unpin_context(ctx);
P
Peter Zijlstra 已提交
9649

9650
	if (move_group)
P
Peter Zijlstra 已提交
9651
		mutex_unlock(&gctx->mutex);
9652
	mutex_unlock(&ctx->mutex);
9653

9654 9655 9656 9657 9658
	if (task) {
		mutex_unlock(&task->signal->cred_guard_mutex);
		put_task_struct(task);
	}

9659 9660
	put_online_cpus();

9661 9662 9663
	mutex_lock(&current->perf_event_mutex);
	list_add_tail(&event->owner_entry, &current->perf_event_list);
	mutex_unlock(&current->perf_event_mutex);
9664

9665 9666 9667 9668 9669 9670
	/*
	 * 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().
	 */
9671
	fdput(group);
9672 9673
	fd_install(event_fd, event_file);
	return event_fd;
T
Thomas Gleixner 已提交
9674

9675 9676 9677 9678 9679 9680
err_locked:
	if (move_group)
		mutex_unlock(&gctx->mutex);
	mutex_unlock(&ctx->mutex);
/* err_file: */
	fput(event_file);
9681
err_context:
9682
	perf_unpin_context(ctx);
9683
	put_ctx(ctx);
9684
err_alloc:
P
Peter Zijlstra 已提交
9685 9686 9687 9688 9689 9690
	/*
	 * 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);
9691 9692 9693
err_cred:
	if (task)
		mutex_unlock(&task->signal->cred_guard_mutex);
9694
err_cpus:
9695
	put_online_cpus();
9696
err_task:
P
Peter Zijlstra 已提交
9697 9698
	if (task)
		put_task_struct(task);
9699
err_group_fd:
9700
	fdput(group);
9701 9702
err_fd:
	put_unused_fd(event_fd);
9703
	return err;
T
Thomas Gleixner 已提交
9704 9705
}

9706 9707 9708 9709 9710
/**
 * 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
9711
 * @task: task to profile (NULL for percpu)
9712 9713 9714
 */
struct perf_event *
perf_event_create_kernel_counter(struct perf_event_attr *attr, int cpu,
M
Matt Helsley 已提交
9715
				 struct task_struct *task,
9716 9717
				 perf_overflow_handler_t overflow_handler,
				 void *context)
9718 9719
{
	struct perf_event_context *ctx;
9720
	struct perf_event *event;
9721
	int err;
9722

9723 9724 9725
	/*
	 * Get the target context (task or percpu):
	 */
9726

9727
	event = perf_event_alloc(attr, cpu, task, NULL, NULL,
9728
				 overflow_handler, context, -1);
9729 9730 9731 9732
	if (IS_ERR(event)) {
		err = PTR_ERR(event);
		goto err;
	}
9733

9734
	/* Mark owner so we could distinguish it from user events. */
9735
	event->owner = TASK_TOMBSTONE;
9736

9737
	ctx = find_get_context(event->pmu, task, event);
9738 9739
	if (IS_ERR(ctx)) {
		err = PTR_ERR(ctx);
9740
		goto err_free;
9741
	}
9742 9743 9744

	WARN_ON_ONCE(ctx->parent_ctx);
	mutex_lock(&ctx->mutex);
9745 9746 9747 9748 9749
	if (ctx->task == TASK_TOMBSTONE) {
		err = -ESRCH;
		goto err_unlock;
	}

9750 9751
	if (!exclusive_event_installable(event, ctx)) {
		err = -EBUSY;
9752
		goto err_unlock;
9753 9754
	}

9755
	perf_install_in_context(ctx, event, cpu);
9756
	perf_unpin_context(ctx);
9757 9758 9759 9760
	mutex_unlock(&ctx->mutex);

	return event;

9761 9762 9763 9764
err_unlock:
	mutex_unlock(&ctx->mutex);
	perf_unpin_context(ctx);
	put_ctx(ctx);
9765 9766 9767
err_free:
	free_event(event);
err:
9768
	return ERR_PTR(err);
9769
}
9770
EXPORT_SYMBOL_GPL(perf_event_create_kernel_counter);
9771

9772 9773 9774 9775 9776 9777 9778 9779 9780 9781
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
9782 9783 9784 9785 9786
	/*
	 * See perf_event_ctx_lock() for comments on the details
	 * of swizzling perf_event::ctx.
	 */
	mutex_lock_double(&src_ctx->mutex, &dst_ctx->mutex);
9787 9788
	list_for_each_entry_safe(event, tmp, &src_ctx->event_list,
				 event_entry) {
9789
		perf_remove_from_context(event, 0);
9790
		unaccount_event_cpu(event, src_cpu);
9791
		put_ctx(src_ctx);
9792
		list_add(&event->migrate_entry, &events);
9793 9794
	}

9795 9796 9797
	/*
	 * Wait for the events to quiesce before re-instating them.
	 */
9798 9799
	synchronize_rcu();

9800 9801 9802 9803 9804 9805 9806 9807 9808 9809 9810 9811 9812 9813 9814 9815 9816 9817 9818 9819 9820 9821 9822 9823
	/*
	 * 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.
	 */
9824 9825
	list_for_each_entry_safe(event, tmp, &events, migrate_entry) {
		list_del(&event->migrate_entry);
9826 9827
		if (event->state >= PERF_EVENT_STATE_OFF)
			event->state = PERF_EVENT_STATE_INACTIVE;
9828
		account_event_cpu(event, dst_cpu);
9829 9830 9831 9832
		perf_install_in_context(dst_ctx, event, dst_cpu);
		get_ctx(dst_ctx);
	}
	mutex_unlock(&dst_ctx->mutex);
P
Peter Zijlstra 已提交
9833
	mutex_unlock(&src_ctx->mutex);
9834 9835 9836
}
EXPORT_SYMBOL_GPL(perf_pmu_migrate_context);

9837
static void sync_child_event(struct perf_event *child_event,
9838
			       struct task_struct *child)
9839
{
9840
	struct perf_event *parent_event = child_event->parent;
9841
	u64 child_val;
9842

9843 9844
	if (child_event->attr.inherit_stat)
		perf_event_read_event(child_event, child);
9845

P
Peter Zijlstra 已提交
9846
	child_val = perf_event_count(child_event);
9847 9848 9849 9850

	/*
	 * Add back the child's count to the parent's count:
	 */
9851
	atomic64_add(child_val, &parent_event->child_count);
9852 9853 9854 9855
	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);
9856 9857
}

9858
static void
9859 9860 9861
perf_event_exit_event(struct perf_event *child_event,
		      struct perf_event_context *child_ctx,
		      struct task_struct *child)
9862
{
9863 9864
	struct perf_event *parent_event = child_event->parent;

9865 9866 9867 9868 9869 9870 9871 9872 9873 9874 9875 9876
	/*
	 * 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.
	 */
9877 9878 9879
	raw_spin_lock_irq(&child_ctx->lock);
	WARN_ON_ONCE(child_ctx->is_active);

9880
	if (parent_event)
9881 9882
		perf_group_detach(child_event);
	list_del_event(child_event, child_ctx);
P
Peter Zijlstra 已提交
9883
	child_event->state = PERF_EVENT_STATE_EXIT; /* is_event_hup() */
9884
	raw_spin_unlock_irq(&child_ctx->lock);
9885

9886
	/*
9887
	 * Parent events are governed by their filedesc, retain them.
9888
	 */
9889
	if (!parent_event) {
9890
		perf_event_wakeup(child_event);
9891
		return;
9892
	}
9893 9894 9895 9896 9897 9898 9899 9900 9901 9902 9903 9904 9905 9906 9907 9908 9909 9910 9911 9912
	/*
	 * 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);
9913 9914
}

P
Peter Zijlstra 已提交
9915
static void perf_event_exit_task_context(struct task_struct *child, int ctxn)
9916
{
9917
	struct perf_event_context *child_ctx, *clone_ctx = NULL;
9918 9919 9920
	struct perf_event *child_event, *next;

	WARN_ON_ONCE(child != current);
9921

9922
	child_ctx = perf_pin_task_context(child, ctxn);
9923
	if (!child_ctx)
9924 9925
		return;

9926
	/*
9927 9928 9929 9930 9931 9932 9933 9934
	 * 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().
9935
	 */
9936
	mutex_lock(&child_ctx->mutex);
9937 9938

	/*
9939 9940 9941
	 * 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.
9942
	 */
9943
	raw_spin_lock_irq(&child_ctx->lock);
9944
	task_ctx_sched_out(__get_cpu_context(child_ctx), child_ctx);
9945

9946
	/*
9947 9948
	 * Now that the context is inactive, destroy the task <-> ctx relation
	 * and mark the context dead.
9949
	 */
9950 9951 9952 9953
	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 */
9954

9955
	clone_ctx = unclone_ctx(child_ctx);
9956
	raw_spin_unlock_irq(&child_ctx->lock);
P
Peter Zijlstra 已提交
9957

9958 9959
	if (clone_ctx)
		put_ctx(clone_ctx);
9960

P
Peter Zijlstra 已提交
9961
	/*
9962 9963 9964
	 * 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
9965
	 */
9966
	perf_event_task(child, child_ctx, 0);
9967

9968
	list_for_each_entry_safe(child_event, next, &child_ctx->event_list, event_entry)
9969
		perf_event_exit_event(child_event, child_ctx, child);
9970

9971 9972 9973
	mutex_unlock(&child_ctx->mutex);

	put_ctx(child_ctx);
9974 9975
}

P
Peter Zijlstra 已提交
9976 9977
/*
 * When a child task exits, feed back event values to parent events.
9978 9979 9980
 *
 * Can be called with cred_guard_mutex held when called from
 * install_exec_creds().
P
Peter Zijlstra 已提交
9981 9982 9983
 */
void perf_event_exit_task(struct task_struct *child)
{
P
Peter Zijlstra 已提交
9984
	struct perf_event *event, *tmp;
P
Peter Zijlstra 已提交
9985 9986
	int ctxn;

P
Peter Zijlstra 已提交
9987 9988 9989 9990 9991 9992 9993 9994 9995 9996
	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.
		 */
9997
		smp_store_release(&event->owner, NULL);
P
Peter Zijlstra 已提交
9998 9999 10000
	}
	mutex_unlock(&child->perf_event_mutex);

P
Peter Zijlstra 已提交
10001 10002
	for_each_task_context_nr(ctxn)
		perf_event_exit_task_context(child, ctxn);
J
Jiri Olsa 已提交
10003 10004 10005 10006 10007 10008 10009 10010

	/*
	 * 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
10011 10012
}

10013 10014 10015 10016 10017 10018 10019 10020 10021 10022 10023 10024
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);

10025
	put_event(parent);
10026

P
Peter Zijlstra 已提交
10027
	raw_spin_lock_irq(&ctx->lock);
10028
	perf_group_detach(event);
10029
	list_del_event(event, ctx);
P
Peter Zijlstra 已提交
10030
	raw_spin_unlock_irq(&ctx->lock);
10031 10032 10033
	free_event(event);
}

10034
/*
P
Peter Zijlstra 已提交
10035
 * Free an unexposed, unused context as created by inheritance by
P
Peter Zijlstra 已提交
10036
 * perf_event_init_task below, used by fork() in case of fail.
P
Peter Zijlstra 已提交
10037 10038 10039
 *
 * Not all locks are strictly required, but take them anyway to be nice and
 * help out with the lockdep assertions.
10040
 */
10041
void perf_event_free_task(struct task_struct *task)
10042
{
P
Peter Zijlstra 已提交
10043
	struct perf_event_context *ctx;
10044
	struct perf_event *event, *tmp;
P
Peter Zijlstra 已提交
10045
	int ctxn;
10046

P
Peter Zijlstra 已提交
10047 10048 10049 10050
	for_each_task_context_nr(ctxn) {
		ctx = task->perf_event_ctxp[ctxn];
		if (!ctx)
			continue;
10051

P
Peter Zijlstra 已提交
10052
		mutex_lock(&ctx->mutex);
10053
again:
P
Peter Zijlstra 已提交
10054 10055 10056
		list_for_each_entry_safe(event, tmp, &ctx->pinned_groups,
				group_entry)
			perf_free_event(event, ctx);
10057

P
Peter Zijlstra 已提交
10058 10059 10060
		list_for_each_entry_safe(event, tmp, &ctx->flexible_groups,
				group_entry)
			perf_free_event(event, ctx);
10061

P
Peter Zijlstra 已提交
10062 10063 10064
		if (!list_empty(&ctx->pinned_groups) ||
				!list_empty(&ctx->flexible_groups))
			goto again;
10065

P
Peter Zijlstra 已提交
10066
		mutex_unlock(&ctx->mutex);
10067

P
Peter Zijlstra 已提交
10068 10069
		put_ctx(ctx);
	}
10070 10071
}

10072 10073 10074 10075 10076 10077 10078 10079
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]);
}

10080
struct file *perf_event_get(unsigned int fd)
10081
{
10082
	struct file *file;
10083

10084 10085 10086
	file = fget_raw(fd);
	if (!file)
		return ERR_PTR(-EBADF);
10087

10088 10089 10090 10091
	if (file->f_op != &perf_fops) {
		fput(file);
		return ERR_PTR(-EBADF);
	}
10092

10093
	return file;
10094 10095 10096 10097 10098 10099 10100 10101 10102 10103
}

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
10104 10105 10106 10107 10108 10109 10110 10111 10112 10113 10114
/*
 * 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)
{
10115
	enum perf_event_active_state parent_state = parent_event->state;
P
Peter Zijlstra 已提交
10116
	struct perf_event *child_event;
10117
	unsigned long flags;
P
Peter Zijlstra 已提交
10118 10119 10120 10121 10122 10123 10124 10125 10126 10127 10128 10129

	/*
	 * 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,
10130
					   child,
P
Peter Zijlstra 已提交
10131
					   group_leader, parent_event,
10132
					   NULL, NULL, -1);
P
Peter Zijlstra 已提交
10133 10134
	if (IS_ERR(child_event))
		return child_event;
10135

10136 10137 10138 10139 10140 10141 10142
	/*
	 * 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);
10143 10144
	if (is_orphaned_event(parent_event) ||
	    !atomic_long_inc_not_zero(&parent_event->refcount)) {
10145
		mutex_unlock(&parent_event->child_mutex);
10146 10147 10148 10149
		free_event(child_event);
		return NULL;
	}

P
Peter Zijlstra 已提交
10150 10151 10152 10153 10154 10155 10156
	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.
	 */
10157
	if (parent_state >= PERF_EVENT_STATE_INACTIVE)
P
Peter Zijlstra 已提交
10158 10159 10160 10161 10162 10163 10164 10165 10166 10167 10168 10169 10170 10171 10172 10173
		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;
10174 10175
	child_event->overflow_handler_context
		= parent_event->overflow_handler_context;
P
Peter Zijlstra 已提交
10176

10177 10178 10179 10180
	/*
	 * Precalculate sample_data sizes
	 */
	perf_event__header_size(child_event);
10181
	perf_event__id_header_size(child_event);
10182

P
Peter Zijlstra 已提交
10183 10184 10185
	/*
	 * Link it up in the child's context:
	 */
10186
	raw_spin_lock_irqsave(&child_ctx->lock, flags);
P
Peter Zijlstra 已提交
10187
	add_event_to_ctx(child_event, child_ctx);
10188
	raw_spin_unlock_irqrestore(&child_ctx->lock, flags);
P
Peter Zijlstra 已提交
10189 10190 10191 10192 10193 10194 10195 10196 10197 10198 10199 10200 10201 10202 10203 10204 10205 10206 10207 10208 10209 10210 10211 10212 10213 10214 10215 10216 10217 10218 10219

	/*
	 * 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;
10220 10221 10222 10223 10224
}

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
10225
		   struct task_struct *child, int ctxn,
10226 10227 10228
		   int *inherited_all)
{
	int ret;
P
Peter Zijlstra 已提交
10229
	struct perf_event_context *child_ctx;
10230 10231 10232 10233

	if (!event->attr.inherit) {
		*inherited_all = 0;
		return 0;
10234 10235
	}

10236
	child_ctx = child->perf_event_ctxp[ctxn];
10237 10238 10239 10240 10241 10242 10243
	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.
		 */
10244

10245
		child_ctx = alloc_perf_context(parent_ctx->pmu, child);
10246 10247
		if (!child_ctx)
			return -ENOMEM;
10248

P
Peter Zijlstra 已提交
10249
		child->perf_event_ctxp[ctxn] = child_ctx;
10250 10251 10252 10253 10254 10255 10256 10257 10258
	}

	ret = inherit_group(event, parent, parent_ctx,
			    child, child_ctx);

	if (ret)
		*inherited_all = 0;

	return ret;
10259 10260
}

10261
/*
10262
 * Initialize the perf_event context in task_struct
10263
 */
10264
static int perf_event_init_context(struct task_struct *child, int ctxn)
10265
{
10266
	struct perf_event_context *child_ctx, *parent_ctx;
10267 10268
	struct perf_event_context *cloned_ctx;
	struct perf_event *event;
10269
	struct task_struct *parent = current;
10270
	int inherited_all = 1;
10271
	unsigned long flags;
10272
	int ret = 0;
10273

P
Peter Zijlstra 已提交
10274
	if (likely(!parent->perf_event_ctxp[ctxn]))
10275 10276
		return 0;

10277
	/*
10278 10279
	 * If the parent's context is a clone, pin it so it won't get
	 * swapped under us.
10280
	 */
P
Peter Zijlstra 已提交
10281
	parent_ctx = perf_pin_task_context(parent, ctxn);
10282 10283
	if (!parent_ctx)
		return 0;
10284

10285 10286 10287 10288 10289 10290 10291
	/*
	 * 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.
	 */

10292 10293 10294 10295
	/*
	 * Lock the parent list. No need to lock the child - not PID
	 * hashed yet and not running, so nobody can access it.
	 */
10296
	mutex_lock(&parent_ctx->mutex);
10297 10298 10299 10300 10301

	/*
	 * We dont have to disable NMIs - we are only looking at
	 * the list, not manipulating it:
	 */
10302
	list_for_each_entry(event, &parent_ctx->pinned_groups, group_entry) {
P
Peter Zijlstra 已提交
10303 10304
		ret = inherit_task_group(event, parent, parent_ctx,
					 child, ctxn, &inherited_all);
10305 10306 10307
		if (ret)
			break;
	}
10308

10309 10310 10311 10312 10313 10314 10315 10316 10317
	/*
	 * 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);

10318
	list_for_each_entry(event, &parent_ctx->flexible_groups, group_entry) {
P
Peter Zijlstra 已提交
10319 10320
		ret = inherit_task_group(event, parent, parent_ctx,
					 child, ctxn, &inherited_all);
10321
		if (ret)
10322
			break;
10323 10324
	}

10325 10326 10327
	raw_spin_lock_irqsave(&parent_ctx->lock, flags);
	parent_ctx->rotate_disable = 0;

P
Peter Zijlstra 已提交
10328
	child_ctx = child->perf_event_ctxp[ctxn];
10329

10330
	if (child_ctx && inherited_all) {
10331 10332 10333
		/*
		 * 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
10334 10335 10336
		 *
		 * Note that if the parent is a clone, the holding of
		 * parent_ctx->lock avoids it from being uncloned.
10337
		 */
P
Peter Zijlstra 已提交
10338
		cloned_ctx = parent_ctx->parent_ctx;
10339 10340
		if (cloned_ctx) {
			child_ctx->parent_ctx = cloned_ctx;
10341
			child_ctx->parent_gen = parent_ctx->parent_gen;
10342 10343 10344 10345 10346
		} else {
			child_ctx->parent_ctx = parent_ctx;
			child_ctx->parent_gen = parent_ctx->generation;
		}
		get_ctx(child_ctx->parent_ctx);
10347 10348
	}

P
Peter Zijlstra 已提交
10349
	raw_spin_unlock_irqrestore(&parent_ctx->lock, flags);
10350
	mutex_unlock(&parent_ctx->mutex);
10351

10352
	perf_unpin_context(parent_ctx);
10353
	put_ctx(parent_ctx);
10354

10355
	return ret;
10356 10357
}

P
Peter Zijlstra 已提交
10358 10359 10360 10361 10362 10363 10364
/*
 * Initialize the perf_event context in task_struct
 */
int perf_event_init_task(struct task_struct *child)
{
	int ctxn, ret;

10365 10366 10367 10368
	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
10369 10370
	for_each_task_context_nr(ctxn) {
		ret = perf_event_init_context(child, ctxn);
P
Peter Zijlstra 已提交
10371 10372
		if (ret) {
			perf_event_free_task(child);
P
Peter Zijlstra 已提交
10373
			return ret;
P
Peter Zijlstra 已提交
10374
		}
P
Peter Zijlstra 已提交
10375 10376 10377 10378 10379
	}

	return 0;
}

10380 10381
static void __init perf_event_init_all_cpus(void)
{
10382
	struct swevent_htable *swhash;
10383 10384 10385
	int cpu;

	for_each_possible_cpu(cpu) {
10386 10387
		swhash = &per_cpu(swevent_htable, cpu);
		mutex_init(&swhash->hlist_mutex);
10388
		INIT_LIST_HEAD(&per_cpu(active_ctx_list, cpu));
10389 10390 10391

		INIT_LIST_HEAD(&per_cpu(pmu_sb_events.list, cpu));
		raw_spin_lock_init(&per_cpu(pmu_sb_events.lock, cpu));
10392 10393 10394
	}
}

10395
int perf_event_init_cpu(unsigned int cpu)
T
Thomas Gleixner 已提交
10396
{
P
Peter Zijlstra 已提交
10397
	struct swevent_htable *swhash = &per_cpu(swevent_htable, cpu);
T
Thomas Gleixner 已提交
10398

10399
	mutex_lock(&swhash->hlist_mutex);
10400
	if (swhash->hlist_refcount > 0 && !swevent_hlist_deref(swhash)) {
10401 10402
		struct swevent_hlist *hlist;

10403 10404 10405
		hlist = kzalloc_node(sizeof(*hlist), GFP_KERNEL, cpu_to_node(cpu));
		WARN_ON(!hlist);
		rcu_assign_pointer(swhash->swevent_hlist, hlist);
10406
	}
10407
	mutex_unlock(&swhash->hlist_mutex);
10408
	return 0;
T
Thomas Gleixner 已提交
10409 10410
}

10411
#if defined CONFIG_HOTPLUG_CPU || defined CONFIG_KEXEC_CORE
P
Peter Zijlstra 已提交
10412
static void __perf_event_exit_context(void *__info)
T
Thomas Gleixner 已提交
10413
{
P
Peter Zijlstra 已提交
10414
	struct perf_event_context *ctx = __info;
10415 10416
	struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
	struct perf_event *event;
T
Thomas Gleixner 已提交
10417

10418 10419
	raw_spin_lock(&ctx->lock);
	list_for_each_entry(event, &ctx->event_list, event_entry)
10420
		__perf_remove_from_context(event, cpuctx, ctx, (void *)DETACH_GROUP);
10421
	raw_spin_unlock(&ctx->lock);
T
Thomas Gleixner 已提交
10422
}
P
Peter Zijlstra 已提交
10423 10424 10425 10426 10427 10428 10429 10430 10431

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) {
10432
		ctx = &per_cpu_ptr(pmu->pmu_cpu_context, cpu)->ctx;
P
Peter Zijlstra 已提交
10433 10434 10435 10436 10437 10438 10439

		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);
}
10440 10441 10442 10443 10444
#else

static void perf_event_exit_cpu_context(int cpu) { }

#endif
P
Peter Zijlstra 已提交
10445

10446
int perf_event_exit_cpu(unsigned int cpu)
T
Thomas Gleixner 已提交
10447
{
P
Peter Zijlstra 已提交
10448
	perf_event_exit_cpu_context(cpu);
10449
	return 0;
T
Thomas Gleixner 已提交
10450 10451
}

P
Peter Zijlstra 已提交
10452 10453 10454 10455 10456 10457 10458 10459 10460 10461 10462 10463 10464 10465 10466 10467 10468 10469 10470 10471
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,
};

10472
void __init perf_event_init(void)
T
Thomas Gleixner 已提交
10473
{
10474 10475
	int ret;

P
Peter Zijlstra 已提交
10476 10477
	idr_init(&pmu_idr);

10478
	perf_event_init_all_cpus();
10479
	init_srcu_struct(&pmus_srcu);
P
Peter Zijlstra 已提交
10480 10481 10482
	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);
10483
	perf_tp_register();
10484
	perf_event_init_cpu(smp_processor_id());
P
Peter Zijlstra 已提交
10485
	register_reboot_notifier(&perf_reboot_notifier);
10486 10487 10488

	ret = init_hw_breakpoint();
	WARN(ret, "hw_breakpoint initialization failed with: %d", ret);
10489

10490 10491 10492 10493 10494 10495
	/*
	 * 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
10496
}
P
Peter Zijlstra 已提交
10497

10498 10499 10500 10501 10502 10503 10504 10505 10506 10507 10508
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;
}
10509
EXPORT_SYMBOL_GPL(perf_event_sysfs_show);
10510

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Peter Zijlstra 已提交
10511 10512 10513 10514 10515 10516 10517 10518 10519 10520 10521 10522 10523 10524 10525 10526 10527 10528 10529 10530 10531 10532 10533 10534 10535 10536 10537
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
10538 10539

#ifdef CONFIG_CGROUP_PERF
10540 10541
static struct cgroup_subsys_state *
perf_cgroup_css_alloc(struct cgroup_subsys_state *parent_css)
S
Stephane Eranian 已提交
10542 10543 10544
{
	struct perf_cgroup *jc;

10545
	jc = kzalloc(sizeof(*jc), GFP_KERNEL);
S
Stephane Eranian 已提交
10546 10547 10548 10549 10550 10551 10552 10553 10554 10555 10556 10557
	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;
}

10558
static void perf_cgroup_css_free(struct cgroup_subsys_state *css)
S
Stephane Eranian 已提交
10559
{
10560 10561
	struct perf_cgroup *jc = container_of(css, struct perf_cgroup, css);

S
Stephane Eranian 已提交
10562 10563 10564 10565 10566 10567 10568
	free_percpu(jc->info);
	kfree(jc);
}

static int __perf_cgroup_move(void *info)
{
	struct task_struct *task = info;
10569
	rcu_read_lock();
S
Stephane Eranian 已提交
10570
	perf_cgroup_switch(task, PERF_CGROUP_SWOUT | PERF_CGROUP_SWIN);
10571
	rcu_read_unlock();
S
Stephane Eranian 已提交
10572 10573 10574
	return 0;
}

10575
static void perf_cgroup_attach(struct cgroup_taskset *tset)
S
Stephane Eranian 已提交
10576
{
10577
	struct task_struct *task;
10578
	struct cgroup_subsys_state *css;
10579

10580
	cgroup_taskset_for_each(task, css, tset)
10581
		task_function_call(task, __perf_cgroup_move, task);
S
Stephane Eranian 已提交
10582 10583
}

10584
struct cgroup_subsys perf_event_cgrp_subsys = {
10585 10586
	.css_alloc	= perf_cgroup_css_alloc,
	.css_free	= perf_cgroup_css_free,
10587
	.attach		= perf_cgroup_attach,
S
Stephane Eranian 已提交
10588 10589
};
#endif /* CONFIG_CGROUP_PERF */