core.c 245.6 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_WARNING
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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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638 639
		return;

640
	cgrp = perf_cgroup_from_task(task, ctx);
S
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641
	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
S
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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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745
{
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;
		}
	}
}
#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)
{
}

875 876
static inline void perf_cgroup_sched_out(struct task_struct *task,
					 struct task_struct *next)
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877 878 879
{
}

880 881
static inline void perf_cgroup_sched_in(struct task_struct *prev,
					struct task_struct *task)
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882 883 884 885 886 887 888 889 890 891 892
{
}

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
893 894
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)
{
}
#endif

925 926 927 928 929 930 931 932
/*
 * 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
 */
933
static enum hrtimer_restart perf_mux_hrtimer_handler(struct hrtimer *hr)
934 935 936 937 938 939 940 941 942
{
	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)
945
		hrtimer_forward_now(hr, cpuctx->hrtimer_interval);
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	else
		cpuctx->hrtimer_active = 0;
	raw_spin_unlock(&cpuctx->hrtimer_lock);
949

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	return rotations ? HRTIMER_RESTART : HRTIMER_NORESTART;
951 952
}

953
static void __perf_mux_hrtimer_init(struct perf_cpu_context *cpuctx, int cpu)
954
{
955
	struct hrtimer *timer = &cpuctx->hrtimer;
956
	struct pmu *pmu = cpuctx->ctx.pmu;
957
	u64 interval;
958 959 960 961 962

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

963 964 965 966
	/*
	 * check default is sane, if not set then force to
	 * default interval (1/tick)
	 */
967 968 969
	interval = pmu->hrtimer_interval_ms;
	if (interval < 1)
		interval = pmu->hrtimer_interval_ms = PERF_CPU_HRTIMER;
970

971
	cpuctx->hrtimer_interval = ns_to_ktime(NSEC_PER_MSEC * interval);
972

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973 974
	raw_spin_lock_init(&cpuctx->hrtimer_lock);
	hrtimer_init(timer, CLOCK_MONOTONIC, HRTIMER_MODE_ABS_PINNED);
975
	timer->function = perf_mux_hrtimer_handler;
976 977
}

978
static int perf_mux_hrtimer_restart(struct perf_cpu_context *cpuctx)
979
{
980
	struct hrtimer *timer = &cpuctx->hrtimer;
981
	struct pmu *pmu = cpuctx->ctx.pmu;
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Peter Zijlstra 已提交
982
	unsigned long flags;
983 984 985

	/* not for SW PMU */
	if (pmu->task_ctx_nr == perf_sw_context)
986
		return 0;
987

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988 989 990 991 992 993 994
	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);
995

996
	return 0;
997 998
}

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999
void perf_pmu_disable(struct pmu *pmu)
1000
{
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1001 1002 1003
	int *count = this_cpu_ptr(pmu->pmu_disable_count);
	if (!(*count)++)
		pmu->pmu_disable(pmu);
1004 1005
}

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1006
void perf_pmu_enable(struct pmu *pmu)
1007
{
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1008 1009 1010
	int *count = this_cpu_ptr(pmu->pmu_disable_count);
	if (!--(*count))
		pmu->pmu_enable(pmu);
1011 1012
}

1013
static DEFINE_PER_CPU(struct list_head, active_ctx_list);
1014 1015

/*
1016 1017 1018 1019
 * 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.
1020
 */
1021
static void perf_event_ctx_activate(struct perf_event_context *ctx)
1022
{
1023
	struct list_head *head = this_cpu_ptr(&active_ctx_list);
1024

1025
	WARN_ON(!irqs_disabled());
1026

1027 1028 1029 1030 1031 1032 1033 1034 1035 1036 1037 1038
	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);
1039 1040
}

1041
static void get_ctx(struct perf_event_context *ctx)
1042
{
1043
	WARN_ON(!atomic_inc_not_zero(&ctx->refcount));
1044 1045
}

1046 1047 1048 1049 1050 1051 1052 1053 1054
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);
}

1055
static void put_ctx(struct perf_event_context *ctx)
1056
{
1057 1058 1059
	if (atomic_dec_and_test(&ctx->refcount)) {
		if (ctx->parent_ctx)
			put_ctx(ctx->parent_ctx);
1060
		if (ctx->task && ctx->task != TASK_TOMBSTONE)
1061
			put_task_struct(ctx->task);
1062
		call_rcu(&ctx->rcu_head, free_ctx);
1063
	}
1064 1065
}

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1066 1067 1068 1069 1070 1071 1072
/*
 * 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.
 *
1073 1074 1075 1076
 * 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 ]
1077 1078
 *      perf_event_exit_event()
 *        put_event()			[ parent, 1 ]
1079 1080 1081 1082 1083 1084 1085 1086 1087 1088 1089 1090 1091 1092 1093 1094 1095
 *
 *  - 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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1096 1097 1098 1099 1100 1101 1102 1103 1104 1105 1106 1107 1108 1109 1110 1111 1112 1113 1114 1115 1116 1117 1118
 *
 * 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:
1119
 *    cred_guard_mutex
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1120 1121 1122
 *	task_struct::perf_event_mutex
 *	  perf_event_context::mutex
 *	    perf_event::child_mutex;
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1123
 *	      perf_event_context::lock
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1124 1125 1126
 *	    perf_event::mmap_mutex
 *	    mmap_sem
 */
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1127 1128
static struct perf_event_context *
perf_event_ctx_lock_nested(struct perf_event *event, int nesting)
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1129 1130 1131 1132 1133 1134 1135 1136 1137 1138 1139 1140
{
	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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1141
	mutex_lock_nested(&ctx->mutex, nesting);
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1142 1143 1144 1145 1146 1147 1148 1149 1150
	if (event->ctx != ctx) {
		mutex_unlock(&ctx->mutex);
		put_ctx(ctx);
		goto again;
	}

	return ctx;
}

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1151 1152 1153 1154 1155 1156
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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1157 1158 1159 1160 1161 1162 1163
static void perf_event_ctx_unlock(struct perf_event *event,
				  struct perf_event_context *ctx)
{
	mutex_unlock(&ctx->mutex);
	put_ctx(ctx);
}

1164 1165 1166 1167 1168 1169 1170
/*
 * 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)
1171
{
1172 1173 1174 1175 1176
	struct perf_event_context *parent_ctx = ctx->parent_ctx;

	lockdep_assert_held(&ctx->lock);

	if (parent_ctx)
1177
		ctx->parent_ctx = NULL;
1178
	ctx->generation++;
1179 1180

	return parent_ctx;
1181 1182
}

1183 1184 1185 1186 1187 1188 1189 1190 1191 1192 1193 1194 1195 1196 1197 1198 1199 1200 1201 1202 1203 1204
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);
}

1205
/*
1206
 * If we inherit events we want to return the parent event id
1207 1208
 * to userspace.
 */
1209
static u64 primary_event_id(struct perf_event *event)
1210
{
1211
	u64 id = event->id;
1212

1213 1214
	if (event->parent)
		id = event->parent->id;
1215 1216 1217 1218

	return id;
}

1219
/*
1220
 * Get the perf_event_context for a task and lock it.
1221
 *
1222 1223 1224
 * This has to cope with with the fact that until it is locked,
 * the context could get moved to another task.
 */
1225
static struct perf_event_context *
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1226
perf_lock_task_context(struct task_struct *task, int ctxn, unsigned long *flags)
1227
{
1228
	struct perf_event_context *ctx;
1229

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1230
retry:
1231 1232 1233
	/*
	 * One of the few rules of preemptible RCU is that one cannot do
	 * rcu_read_unlock() while holding a scheduler (or nested) lock when
1234
	 * part of the read side critical section was irqs-enabled -- see
1235 1236 1237
	 * rcu_read_unlock_special().
	 *
	 * Since ctx->lock nests under rq->lock we must ensure the entire read
1238
	 * side critical section has interrupts disabled.
1239
	 */
1240
	local_irq_save(*flags);
1241
	rcu_read_lock();
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Peter Zijlstra 已提交
1242
	ctx = rcu_dereference(task->perf_event_ctxp[ctxn]);
1243 1244 1245 1246
	if (ctx) {
		/*
		 * If this context is a clone of another, it might
		 * get swapped for another underneath us by
1247
		 * perf_event_task_sched_out, though the
1248 1249 1250 1251 1252 1253
		 * 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.
		 */
1254
		raw_spin_lock(&ctx->lock);
P
Peter Zijlstra 已提交
1255
		if (ctx != rcu_dereference(task->perf_event_ctxp[ctxn])) {
1256
			raw_spin_unlock(&ctx->lock);
1257
			rcu_read_unlock();
1258
			local_irq_restore(*flags);
1259 1260
			goto retry;
		}
1261

1262 1263
		if (ctx->task == TASK_TOMBSTONE ||
		    !atomic_inc_not_zero(&ctx->refcount)) {
1264
			raw_spin_unlock(&ctx->lock);
1265
			ctx = NULL;
P
Peter Zijlstra 已提交
1266 1267
		} else {
			WARN_ON_ONCE(ctx->task != task);
1268
		}
1269 1270
	}
	rcu_read_unlock();
1271 1272
	if (!ctx)
		local_irq_restore(*flags);
1273 1274 1275 1276 1277 1278 1279 1280
	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
1281 1282
static struct perf_event_context *
perf_pin_task_context(struct task_struct *task, int ctxn)
1283
{
1284
	struct perf_event_context *ctx;
1285 1286
	unsigned long flags;

P
Peter Zijlstra 已提交
1287
	ctx = perf_lock_task_context(task, ctxn, &flags);
1288 1289
	if (ctx) {
		++ctx->pin_count;
1290
		raw_spin_unlock_irqrestore(&ctx->lock, flags);
1291 1292 1293 1294
	}
	return ctx;
}

1295
static void perf_unpin_context(struct perf_event_context *ctx)
1296 1297 1298
{
	unsigned long flags;

1299
	raw_spin_lock_irqsave(&ctx->lock, flags);
1300
	--ctx->pin_count;
1301
	raw_spin_unlock_irqrestore(&ctx->lock, flags);
1302 1303
}

1304 1305 1306 1307 1308 1309 1310 1311 1312 1313 1314
/*
 * 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;
}

1315 1316 1317
static u64 perf_event_time(struct perf_event *event)
{
	struct perf_event_context *ctx = event->ctx;
S
Stephane Eranian 已提交
1318 1319 1320 1321

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

1322 1323 1324
	return ctx ? ctx->time : 0;
}

1325 1326 1327 1328 1329 1330 1331 1332
/*
 * 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;

1333 1334
	lockdep_assert_held(&ctx->lock);

1335 1336 1337
	if (event->state < PERF_EVENT_STATE_INACTIVE ||
	    event->group_leader->state < PERF_EVENT_STATE_INACTIVE)
		return;
1338

S
Stephane Eranian 已提交
1339 1340 1341 1342 1343 1344 1345 1346 1347 1348 1349
	/*
	 * 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))
1350
		run_end = perf_cgroup_event_time(event);
S
Stephane Eranian 已提交
1351 1352
	else if (ctx->is_active)
		run_end = ctx->time;
1353 1354 1355 1356
	else
		run_end = event->tstamp_stopped;

	event->total_time_enabled = run_end - event->tstamp_enabled;
1357 1358 1359 1360

	if (event->state == PERF_EVENT_STATE_INACTIVE)
		run_end = event->tstamp_stopped;
	else
1361
		run_end = perf_event_time(event);
1362 1363

	event->total_time_running = run_end - event->tstamp_running;
S
Stephane Eranian 已提交
1364

1365 1366
}

1367 1368 1369 1370 1371 1372 1373 1374 1375 1376 1377 1378
/*
 * 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);
}

1379 1380 1381 1382 1383 1384 1385 1386 1387
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;
}

1388
/*
1389
 * Add a event from the lists for its context.
1390 1391
 * Must be called with ctx->mutex and ctx->lock held.
 */
1392
static void
1393
list_add_event(struct perf_event *event, struct perf_event_context *ctx)
1394
{
P
Peter Zijlstra 已提交
1395 1396
	lockdep_assert_held(&ctx->lock);

1397 1398
	WARN_ON_ONCE(event->attach_state & PERF_ATTACH_CONTEXT);
	event->attach_state |= PERF_ATTACH_CONTEXT;
1399 1400

	/*
1401 1402 1403
	 * 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.
1404
	 */
1405
	if (event->group_leader == event) {
1406 1407
		struct list_head *list;

1408 1409 1410
		if (is_software_event(event))
			event->group_flags |= PERF_GROUP_SOFTWARE;

1411 1412
		list = ctx_group_list(event, ctx);
		list_add_tail(&event->group_entry, list);
P
Peter Zijlstra 已提交
1413
	}
P
Peter Zijlstra 已提交
1414

1415
	if (is_cgroup_event(event))
S
Stephane Eranian 已提交
1416 1417
		ctx->nr_cgroups++;

1418 1419 1420
	list_add_rcu(&event->event_entry, &ctx->event_list);
	ctx->nr_events++;
	if (event->attr.inherit_stat)
1421
		ctx->nr_stat++;
1422 1423

	ctx->generation++;
1424 1425
}

J
Jiri Olsa 已提交
1426 1427 1428 1429 1430 1431 1432 1433 1434
/*
 * 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
1435
static void __perf_event_read_size(struct perf_event *event, int nr_siblings)
1436 1437 1438 1439 1440 1441 1442 1443 1444 1445 1446 1447 1448 1449 1450
{
	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
1451
		nr += nr_siblings;
1452 1453 1454 1455 1456 1457 1458
		size += sizeof(u64);
	}

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

P
Peter Zijlstra 已提交
1459
static void __perf_event_header_size(struct perf_event *event, u64 sample_type)
1460 1461 1462 1463 1464 1465 1466
{
	struct perf_sample_data *data;
	u16 size = 0;

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

1467 1468 1469 1470 1471 1472
	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
1473 1474 1475
	if (sample_type & PERF_SAMPLE_WEIGHT)
		size += sizeof(data->weight);

1476 1477 1478
	if (sample_type & PERF_SAMPLE_READ)
		size += event->read_size;

1479 1480 1481
	if (sample_type & PERF_SAMPLE_DATA_SRC)
		size += sizeof(data->data_src.val);

A
Andi Kleen 已提交
1482 1483 1484
	if (sample_type & PERF_SAMPLE_TRANSACTION)
		size += sizeof(data->txn);

1485 1486 1487
	event->header_size = size;
}

P
Peter Zijlstra 已提交
1488 1489 1490 1491 1492 1493 1494 1495 1496 1497 1498
/*
 * 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);
}

1499 1500 1501 1502 1503 1504
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;

1505 1506 1507 1508 1509 1510
	if (sample_type & PERF_SAMPLE_TID)
		size += sizeof(data->tid_entry);

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

1511 1512 1513
	if (sample_type & PERF_SAMPLE_IDENTIFIER)
		size += sizeof(data->id);

1514 1515 1516 1517 1518 1519 1520 1521 1522
	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);

1523
	event->id_header_size = size;
1524 1525
}

P
Peter Zijlstra 已提交
1526 1527 1528 1529 1530 1531 1532 1533 1534 1535 1536 1537 1538 1539 1540 1541 1542 1543 1544 1545 1546
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;
}

1547 1548
static void perf_group_attach(struct perf_event *event)
{
1549
	struct perf_event *group_leader = event->group_leader, *pos;
1550

P
Peter Zijlstra 已提交
1551 1552 1553 1554 1555 1556
	/*
	 * We can have double attach due to group movement in perf_event_open.
	 */
	if (event->attach_state & PERF_ATTACH_GROUP)
		return;

1557 1558 1559 1560 1561
	event->attach_state |= PERF_ATTACH_GROUP;

	if (group_leader == event)
		return;

P
Peter Zijlstra 已提交
1562 1563
	WARN_ON_ONCE(group_leader->ctx != event->ctx);

1564 1565 1566 1567 1568 1569
	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++;
1570 1571 1572 1573 1574

	perf_event__header_size(group_leader);

	list_for_each_entry(pos, &group_leader->sibling_list, group_entry)
		perf_event__header_size(pos);
1575 1576
}

1577
/*
1578
 * Remove a event from the lists for its context.
1579
 * Must be called with ctx->mutex and ctx->lock held.
1580
 */
1581
static void
1582
list_del_event(struct perf_event *event, struct perf_event_context *ctx)
1583
{
1584
	struct perf_cpu_context *cpuctx;
P
Peter Zijlstra 已提交
1585 1586 1587 1588

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

1589 1590 1591 1592
	/*
	 * We can have double detach due to exit/hot-unplug + close.
	 */
	if (!(event->attach_state & PERF_ATTACH_CONTEXT))
1593
		return;
1594 1595 1596

	event->attach_state &= ~PERF_ATTACH_CONTEXT;

1597
	if (is_cgroup_event(event)) {
S
Stephane Eranian 已提交
1598
		ctx->nr_cgroups--;
1599 1600 1601 1602
		/*
		 * Because cgroup events are always per-cpu events, this will
		 * always be called from the right CPU.
		 */
1603 1604
		cpuctx = __get_cpu_context(ctx);
		/*
1605 1606
		 * If there are no more cgroup events then clear cgrp to avoid
		 * stale pointer in update_cgrp_time_from_cpuctx().
1607 1608 1609 1610
		 */
		if (!ctx->nr_cgroups)
			cpuctx->cgrp = NULL;
	}
S
Stephane Eranian 已提交
1611

1612 1613
	ctx->nr_events--;
	if (event->attr.inherit_stat)
1614
		ctx->nr_stat--;
1615

1616
	list_del_rcu(&event->event_entry);
1617

1618 1619
	if (event->group_leader == event)
		list_del_init(&event->group_entry);
P
Peter Zijlstra 已提交
1620

1621
	update_group_times(event);
1622 1623 1624 1625 1626 1627 1628 1629 1630 1631

	/*
	 * 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;
1632 1633

	ctx->generation++;
1634 1635
}

1636
static void perf_group_detach(struct perf_event *event)
1637 1638
{
	struct perf_event *sibling, *tmp;
1639 1640 1641 1642 1643 1644 1645 1646 1647 1648 1649 1650 1651 1652 1653 1654
	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--;
1655
		goto out;
1656 1657 1658 1659
	}

	if (!list_empty(&event->group_entry))
		list = &event->group_entry;
1660

1661
	/*
1662 1663
	 * If this was a group event with sibling events then
	 * upgrade the siblings to singleton events by adding them
1664
	 * to whatever list we are on.
1665
	 */
1666
	list_for_each_entry_safe(sibling, tmp, &event->sibling_list, group_entry) {
1667 1668
		if (list)
			list_move_tail(&sibling->group_entry, list);
1669
		sibling->group_leader = sibling;
1670 1671 1672

		/* Inherit group flags from the previous leader */
		sibling->group_flags = event->group_flags;
P
Peter Zijlstra 已提交
1673 1674

		WARN_ON_ONCE(sibling->ctx != event->ctx);
1675
	}
1676 1677 1678 1679 1680 1681

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);
1682 1683
}

1684 1685
static bool is_orphaned_event(struct perf_event *event)
{
P
Peter Zijlstra 已提交
1686
	return event->state == PERF_EVENT_STATE_DEAD;
1687 1688
}

1689 1690 1691 1692 1693 1694
static inline int pmu_filter_match(struct perf_event *event)
{
	struct pmu *pmu = event->pmu;
	return pmu->filter_match ? pmu->filter_match(event) : 1;
}

1695 1696 1697
static inline int
event_filter_match(struct perf_event *event)
{
S
Stephane Eranian 已提交
1698
	return (event->cpu == -1 || event->cpu == smp_processor_id())
1699
	    && perf_cgroup_match(event) && pmu_filter_match(event);
1700 1701
}

1702 1703
static void
event_sched_out(struct perf_event *event,
1704
		  struct perf_cpu_context *cpuctx,
1705
		  struct perf_event_context *ctx)
1706
{
1707
	u64 tstamp = perf_event_time(event);
1708
	u64 delta;
P
Peter Zijlstra 已提交
1709 1710 1711 1712

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

1713 1714 1715 1716 1717 1718 1719 1720
	/*
	 * 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:
	 */
	if (event->state == PERF_EVENT_STATE_INACTIVE
	    && !event_filter_match(event)) {
S
Stephane Eranian 已提交
1721
		delta = tstamp - event->tstamp_stopped;
1722
		event->tstamp_running += delta;
1723
		event->tstamp_stopped = tstamp;
1724 1725
	}

1726
	if (event->state != PERF_EVENT_STATE_ACTIVE)
1727
		return;
1728

1729 1730
	perf_pmu_disable(event->pmu);

1731 1732 1733
	event->tstamp_stopped = tstamp;
	event->pmu->del(event, 0);
	event->oncpu = -1;
1734 1735 1736 1737
	event->state = PERF_EVENT_STATE_INACTIVE;
	if (event->pending_disable) {
		event->pending_disable = 0;
		event->state = PERF_EVENT_STATE_OFF;
1738
	}
1739

1740
	if (!is_software_event(event))
1741
		cpuctx->active_oncpu--;
1742 1743
	if (!--ctx->nr_active)
		perf_event_ctx_deactivate(ctx);
1744 1745
	if (event->attr.freq && event->attr.sample_freq)
		ctx->nr_freq--;
1746
	if (event->attr.exclusive || !cpuctx->active_oncpu)
1747
		cpuctx->exclusive = 0;
1748 1749

	perf_pmu_enable(event->pmu);
1750 1751
}

1752
static void
1753
group_sched_out(struct perf_event *group_event,
1754
		struct perf_cpu_context *cpuctx,
1755
		struct perf_event_context *ctx)
1756
{
1757
	struct perf_event *event;
1758
	int state = group_event->state;
1759

1760
	event_sched_out(group_event, cpuctx, ctx);
1761 1762 1763 1764

	/*
	 * Schedule out siblings (if any):
	 */
1765 1766
	list_for_each_entry(event, &group_event->sibling_list, group_entry)
		event_sched_out(event, cpuctx, ctx);
1767

1768
	if (state == PERF_EVENT_STATE_ACTIVE && group_event->attr.exclusive)
1769 1770 1771
		cpuctx->exclusive = 0;
}

1772
#define DETACH_GROUP	0x01UL
1773

T
Thomas Gleixner 已提交
1774
/*
1775
 * Cross CPU call to remove a performance event
T
Thomas Gleixner 已提交
1776
 *
1777
 * We disable the event on the hardware level first. After that we
T
Thomas Gleixner 已提交
1778 1779
 * remove it from the context list.
 */
1780 1781 1782 1783 1784
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
1785
{
1786
	unsigned long flags = (unsigned long)info;
T
Thomas Gleixner 已提交
1787

1788
	event_sched_out(event, cpuctx, ctx);
1789
	if (flags & DETACH_GROUP)
1790
		perf_group_detach(event);
1791
	list_del_event(event, ctx);
1792 1793

	if (!ctx->nr_events && ctx->is_active) {
1794
		ctx->is_active = 0;
1795 1796 1797 1798
		if (ctx->task) {
			WARN_ON_ONCE(cpuctx->task_ctx != ctx);
			cpuctx->task_ctx = NULL;
		}
1799
	}
T
Thomas Gleixner 已提交
1800 1801 1802
}

/*
1803
 * Remove the event from a task's (or a CPU's) list of events.
T
Thomas Gleixner 已提交
1804
 *
1805 1806
 * If event->ctx is a cloned context, callers must make sure that
 * every task struct that event->ctx->task could possibly point to
1807 1808
 * 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.
1809
 * When called from perf_event_exit_task, it's OK because the
1810
 * context has been detached from its task.
T
Thomas Gleixner 已提交
1811
 */
1812
static void perf_remove_from_context(struct perf_event *event, unsigned long flags)
T
Thomas Gleixner 已提交
1813
{
1814
	lockdep_assert_held(&event->ctx->mutex);
T
Thomas Gleixner 已提交
1815

1816
	event_function_call(event, __perf_remove_from_context, (void *)flags);
T
Thomas Gleixner 已提交
1817 1818
}

1819
/*
1820
 * Cross CPU call to disable a performance event
1821
 */
1822 1823 1824 1825
static void __perf_event_disable(struct perf_event *event,
				 struct perf_cpu_context *cpuctx,
				 struct perf_event_context *ctx,
				 void *info)
1826
{
1827 1828
	if (event->state < PERF_EVENT_STATE_INACTIVE)
		return;
1829

1830 1831 1832 1833 1834 1835 1836 1837
	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;
1838 1839
}

1840
/*
1841
 * Disable a event.
1842
 *
1843 1844
 * If event->ctx is a cloned context, callers must make sure that
 * every task struct that event->ctx->task could possibly point to
1845
 * remains valid.  This condition is satisifed when called through
1846 1847
 * perf_event_for_each_child or perf_event_for_each because they
 * hold the top-level event's child_mutex, so any descendant that
1848 1849
 * goes to exit will block in perf_event_exit_event().
 *
1850
 * When called from perf_pending_event it's OK because event->ctx
1851
 * is the current context on this CPU and preemption is disabled,
1852
 * hence we can't get into perf_event_task_sched_out for this context.
1853
 */
P
Peter Zijlstra 已提交
1854
static void _perf_event_disable(struct perf_event *event)
1855
{
1856
	struct perf_event_context *ctx = event->ctx;
1857

1858
	raw_spin_lock_irq(&ctx->lock);
1859
	if (event->state <= PERF_EVENT_STATE_OFF) {
1860
		raw_spin_unlock_irq(&ctx->lock);
1861
		return;
1862
	}
1863
	raw_spin_unlock_irq(&ctx->lock);
1864

1865 1866 1867 1868 1869 1870
	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);
1871
}
P
Peter Zijlstra 已提交
1872 1873 1874 1875 1876 1877 1878 1879 1880 1881 1882 1883 1884

/*
 * 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);
}
1885
EXPORT_SYMBOL_GPL(perf_event_disable);
1886

S
Stephane Eranian 已提交
1887 1888 1889 1890 1891 1892 1893 1894 1895 1896 1897 1898 1899 1900 1901 1902 1903 1904 1905 1906 1907 1908 1909 1910 1911 1912 1913 1914 1915 1916 1917 1918 1919 1920 1921
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
1922 1923 1924
#define MAX_INTERRUPTS (~0ULL)

static void perf_log_throttle(struct perf_event *event, int enable);
1925
static void perf_log_itrace_start(struct perf_event *event);
P
Peter Zijlstra 已提交
1926

1927
static int
1928
event_sched_in(struct perf_event *event,
1929
		 struct perf_cpu_context *cpuctx,
1930
		 struct perf_event_context *ctx)
1931
{
1932
	u64 tstamp = perf_event_time(event);
1933
	int ret = 0;
1934

1935 1936
	lockdep_assert_held(&ctx->lock);

1937
	if (event->state <= PERF_EVENT_STATE_OFF)
1938 1939
		return 0;

1940 1941 1942 1943 1944 1945 1946
	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
1947 1948 1949 1950 1951 1952 1953 1954 1955 1956 1957

	/*
	 * 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;
	}

1958 1959 1960 1961 1962
	/*
	 * The new state must be visible before we turn it on in the hardware:
	 */
	smp_wmb();

1963 1964
	perf_pmu_disable(event->pmu);

1965 1966
	perf_set_shadow_time(event, ctx, tstamp);

1967 1968
	perf_log_itrace_start(event);

P
Peter Zijlstra 已提交
1969
	if (event->pmu->add(event, PERF_EF_START)) {
1970 1971
		event->state = PERF_EVENT_STATE_INACTIVE;
		event->oncpu = -1;
1972 1973
		ret = -EAGAIN;
		goto out;
1974 1975
	}

1976 1977
	event->tstamp_running += tstamp - event->tstamp_stopped;

1978
	if (!is_software_event(event))
1979
		cpuctx->active_oncpu++;
1980 1981
	if (!ctx->nr_active++)
		perf_event_ctx_activate(ctx);
1982 1983
	if (event->attr.freq && event->attr.sample_freq)
		ctx->nr_freq++;
1984

1985
	if (event->attr.exclusive)
1986 1987
		cpuctx->exclusive = 1;

1988 1989 1990 1991
out:
	perf_pmu_enable(event->pmu);

	return ret;
1992 1993
}

1994
static int
1995
group_sched_in(struct perf_event *group_event,
1996
	       struct perf_cpu_context *cpuctx,
1997
	       struct perf_event_context *ctx)
1998
{
1999
	struct perf_event *event, *partial_group = NULL;
P
Peter Zijlstra 已提交
2000
	struct pmu *pmu = ctx->pmu;
2001 2002
	u64 now = ctx->time;
	bool simulate = false;
2003

2004
	if (group_event->state == PERF_EVENT_STATE_OFF)
2005 2006
		return 0;

2007
	pmu->start_txn(pmu, PERF_PMU_TXN_ADD);
2008

2009
	if (event_sched_in(group_event, cpuctx, ctx)) {
P
Peter Zijlstra 已提交
2010
		pmu->cancel_txn(pmu);
2011
		perf_mux_hrtimer_restart(cpuctx);
2012
		return -EAGAIN;
2013
	}
2014 2015 2016 2017

	/*
	 * Schedule in siblings as one group (if any):
	 */
2018
	list_for_each_entry(event, &group_event->sibling_list, group_entry) {
2019
		if (event_sched_in(event, cpuctx, ctx)) {
2020
			partial_group = event;
2021 2022 2023 2024
			goto group_error;
		}
	}

2025
	if (!pmu->commit_txn(pmu))
2026
		return 0;
2027

2028 2029 2030 2031
group_error:
	/*
	 * Groups can be scheduled in as one unit only, so undo any
	 * partial group before returning:
2032 2033 2034 2035 2036 2037 2038 2039 2040 2041
	 * 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.
2042
	 */
2043 2044
	list_for_each_entry(event, &group_event->sibling_list, group_entry) {
		if (event == partial_group)
2045 2046 2047 2048 2049 2050 2051 2052
			simulate = true;

		if (simulate) {
			event->tstamp_running += now - event->tstamp_stopped;
			event->tstamp_stopped = now;
		} else {
			event_sched_out(event, cpuctx, ctx);
		}
2053
	}
2054
	event_sched_out(group_event, cpuctx, ctx);
2055

P
Peter Zijlstra 已提交
2056
	pmu->cancel_txn(pmu);
2057

2058
	perf_mux_hrtimer_restart(cpuctx);
2059

2060 2061 2062
	return -EAGAIN;
}

2063
/*
2064
 * Work out whether we can put this event group on the CPU now.
2065
 */
2066
static int group_can_go_on(struct perf_event *event,
2067 2068 2069 2070
			   struct perf_cpu_context *cpuctx,
			   int can_add_hw)
{
	/*
2071
	 * Groups consisting entirely of software events can always go on.
2072
	 */
2073
	if (event->group_flags & PERF_GROUP_SOFTWARE)
2074 2075 2076
		return 1;
	/*
	 * If an exclusive group is already on, no other hardware
2077
	 * events can go on.
2078 2079 2080 2081 2082
	 */
	if (cpuctx->exclusive)
		return 0;
	/*
	 * If this group is exclusive and there are already
2083
	 * events on the CPU, it can't go on.
2084
	 */
2085
	if (event->attr.exclusive && cpuctx->active_oncpu)
2086 2087 2088 2089 2090 2091 2092 2093
		return 0;
	/*
	 * Otherwise, try to add it if all previous groups were able
	 * to go on.
	 */
	return can_add_hw;
}

2094 2095
static void add_event_to_ctx(struct perf_event *event,
			       struct perf_event_context *ctx)
2096
{
2097 2098
	u64 tstamp = perf_event_time(event);

2099
	list_add_event(event, ctx);
2100
	perf_group_attach(event);
2101 2102 2103
	event->tstamp_enabled = tstamp;
	event->tstamp_running = tstamp;
	event->tstamp_stopped = tstamp;
2104 2105
}

2106 2107 2108
static void ctx_sched_out(struct perf_event_context *ctx,
			  struct perf_cpu_context *cpuctx,
			  enum event_type_t event_type);
2109 2110 2111 2112 2113
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);
2114

2115 2116 2117 2118 2119 2120 2121 2122 2123 2124 2125 2126
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);
}

2127 2128 2129 2130 2131 2132 2133 2134 2135 2136 2137 2138
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);
}

2139 2140
static void ctx_resched(struct perf_cpu_context *cpuctx,
			struct perf_event_context *task_ctx)
2141
{
2142 2143 2144 2145 2146 2147
	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);
2148 2149
}

T
Thomas Gleixner 已提交
2150
/*
2151
 * Cross CPU call to install and enable a performance event
2152
 *
2153 2154
 * 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
2155
 */
2156
static int  __perf_install_in_context(void *info)
T
Thomas Gleixner 已提交
2157
{
2158 2159
	struct perf_event *event = info;
	struct perf_event_context *ctx = event->ctx;
P
Peter Zijlstra 已提交
2160
	struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
2161
	struct perf_event_context *task_ctx = cpuctx->task_ctx;
2162 2163
	bool activate = true;
	int ret = 0;
T
Thomas Gleixner 已提交
2164

2165
	raw_spin_lock(&cpuctx->ctx.lock);
2166
	if (ctx->task) {
2167 2168
		raw_spin_lock(&ctx->lock);
		task_ctx = ctx;
2169 2170 2171 2172

		/* If we're on the wrong CPU, try again */
		if (task_cpu(ctx->task) != smp_processor_id()) {
			ret = -ESRCH;
2173
			goto unlock;
2174
		}
2175

2176
		/*
2177 2178 2179
		 * 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.
2180
		 */
2181 2182 2183 2184 2185
		if (ctx->task != current)
			activate = false;
		else
			WARN_ON_ONCE(cpuctx->task_ctx && cpuctx->task_ctx != ctx);

2186 2187
	} else if (task_ctx) {
		raw_spin_lock(&task_ctx->lock);
2188
	}
2189

2190 2191 2192 2193 2194 2195 2196 2197
	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);
	}

2198
unlock:
2199
	perf_ctx_unlock(cpuctx, task_ctx);
2200

2201
	return ret;
T
Thomas Gleixner 已提交
2202 2203 2204
}

/*
2205 2206 2207
 * Attach a performance event to a context.
 *
 * Very similar to event_function_call, see comment there.
T
Thomas Gleixner 已提交
2208 2209
 */
static void
2210 2211
perf_install_in_context(struct perf_event_context *ctx,
			struct perf_event *event,
T
Thomas Gleixner 已提交
2212 2213
			int cpu)
{
2214
	struct task_struct *task = READ_ONCE(ctx->task);
2215

2216 2217
	lockdep_assert_held(&ctx->mutex);

2218
	event->ctx = ctx;
2219 2220
	if (event->cpu != -1)
		event->cpu = cpu;
2221

2222 2223 2224 2225 2226 2227 2228 2229 2230 2231 2232
	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;

2233 2234 2235 2236
	/*
	 * 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.
	 */
2237
again:
2238
	/*
2239 2240
	 * Cannot use task_function_call() because we need to run on the task's
	 * CPU regardless of whether its current or not.
2241
	 */
2242 2243 2244 2245 2246
	if (!cpu_function_call(task_cpu(task), __perf_install_in_context, event))
		return;

	raw_spin_lock_irq(&ctx->lock);
	task = ctx->task;
2247
	if (WARN_ON_ONCE(task == TASK_TOMBSTONE)) {
2248 2249 2250 2251 2252
		/*
		 * 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().
		 */
2253 2254 2255
		raw_spin_unlock_irq(&ctx->lock);
		return;
	}
2256 2257
	raw_spin_unlock_irq(&ctx->lock);
	/*
2258 2259
	 * Since !ctx->is_active doesn't mean anything, we must IPI
	 * unconditionally.
2260
	 */
2261
	goto again;
T
Thomas Gleixner 已提交
2262 2263
}

2264
/*
2265
 * Put a event into inactive state and update time fields.
2266 2267 2268 2269 2270 2271
 * 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.
 */
2272
static void __perf_event_mark_enabled(struct perf_event *event)
2273
{
2274
	struct perf_event *sub;
2275
	u64 tstamp = perf_event_time(event);
2276

2277
	event->state = PERF_EVENT_STATE_INACTIVE;
2278
	event->tstamp_enabled = tstamp - event->total_time_enabled;
P
Peter Zijlstra 已提交
2279
	list_for_each_entry(sub, &event->sibling_list, group_entry) {
2280 2281
		if (sub->state >= PERF_EVENT_STATE_INACTIVE)
			sub->tstamp_enabled = tstamp - sub->total_time_enabled;
P
Peter Zijlstra 已提交
2282
	}
2283 2284
}

2285
/*
2286
 * Cross CPU call to enable a performance event
2287
 */
2288 2289 2290 2291
static void __perf_event_enable(struct perf_event *event,
				struct perf_cpu_context *cpuctx,
				struct perf_event_context *ctx,
				void *info)
2292
{
2293
	struct perf_event *leader = event->group_leader;
2294
	struct perf_event_context *task_ctx;
2295

P
Peter Zijlstra 已提交
2296 2297
	if (event->state >= PERF_EVENT_STATE_INACTIVE ||
	    event->state <= PERF_EVENT_STATE_ERROR)
2298
		return;
2299

2300 2301 2302
	if (ctx->is_active)
		ctx_sched_out(ctx, cpuctx, EVENT_TIME);

2303
	__perf_event_mark_enabled(event);
2304

2305 2306 2307
	if (!ctx->is_active)
		return;

S
Stephane Eranian 已提交
2308
	if (!event_filter_match(event)) {
2309
		if (is_cgroup_event(event))
S
Stephane Eranian 已提交
2310
			perf_cgroup_defer_enabled(event);
2311
		ctx_sched_in(ctx, cpuctx, EVENT_TIME, current);
2312
		return;
S
Stephane Eranian 已提交
2313
	}
2314

2315
	/*
2316
	 * If the event is in a group and isn't the group leader,
2317
	 * then don't put it on unless the group is on.
2318
	 */
2319 2320
	if (leader != event && leader->state != PERF_EVENT_STATE_ACTIVE) {
		ctx_sched_in(ctx, cpuctx, EVENT_TIME, current);
2321
		return;
2322
	}
2323

2324 2325 2326
	task_ctx = cpuctx->task_ctx;
	if (ctx->task)
		WARN_ON_ONCE(task_ctx != ctx);
2327

2328
	ctx_resched(cpuctx, task_ctx);
2329 2330
}

2331
/*
2332
 * Enable a event.
2333
 *
2334 2335
 * If event->ctx is a cloned context, callers must make sure that
 * every task struct that event->ctx->task could possibly point to
2336
 * remains valid.  This condition is satisfied when called through
2337 2338
 * perf_event_for_each_child or perf_event_for_each as described
 * for perf_event_disable.
2339
 */
P
Peter Zijlstra 已提交
2340
static void _perf_event_enable(struct perf_event *event)
2341
{
2342
	struct perf_event_context *ctx = event->ctx;
2343

2344
	raw_spin_lock_irq(&ctx->lock);
P
Peter Zijlstra 已提交
2345 2346
	if (event->state >= PERF_EVENT_STATE_INACTIVE ||
	    event->state <  PERF_EVENT_STATE_ERROR) {
2347
		raw_spin_unlock_irq(&ctx->lock);
2348 2349 2350 2351
		return;
	}

	/*
2352
	 * If the event is in error state, clear that first.
2353 2354 2355 2356
	 *
	 * 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.
2357
	 */
2358 2359
	if (event->state == PERF_EVENT_STATE_ERROR)
		event->state = PERF_EVENT_STATE_OFF;
2360
	raw_spin_unlock_irq(&ctx->lock);
2361

2362
	event_function_call(event, __perf_event_enable, NULL);
2363
}
P
Peter Zijlstra 已提交
2364 2365 2366 2367 2368 2369 2370 2371 2372 2373 2374 2375

/*
 * 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);
}
2376
EXPORT_SYMBOL_GPL(perf_event_enable);
2377

2378 2379 2380 2381 2382
struct stop_event_data {
	struct perf_event	*event;
	unsigned int		restart;
};

2383 2384
static int __perf_event_stop(void *info)
{
2385 2386
	struct stop_event_data *sd = info;
	struct perf_event *event = sd->event;
2387

2388
	/* if it's already INACTIVE, do nothing */
2389 2390 2391 2392 2393 2394 2395 2396 2397 2398 2399 2400 2401 2402 2403
	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);

2404 2405 2406 2407 2408 2409 2410 2411 2412 2413 2414 2415
	/*
	 * 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);

2416 2417 2418
	return 0;
}

2419 2420 2421 2422 2423 2424 2425 2426 2427 2428 2429 2430 2431 2432 2433 2434 2435 2436 2437 2438 2439 2440 2441 2442 2443 2444 2445 2446 2447 2448 2449 2450 2451 2452 2453 2454 2455 2456 2457 2458 2459 2460 2461 2462 2463 2464 2465 2466 2467 2468 2469 2470 2471 2472 2473 2474 2475 2476 2477 2478 2479 2480 2481 2482 2483
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
2484
static int _perf_event_refresh(struct perf_event *event, int refresh)
2485
{
2486
	/*
2487
	 * not supported on inherited events
2488
	 */
2489
	if (event->attr.inherit || !is_sampling_event(event))
2490 2491
		return -EINVAL;

2492
	atomic_add(refresh, &event->event_limit);
P
Peter Zijlstra 已提交
2493
	_perf_event_enable(event);
2494 2495

	return 0;
2496
}
P
Peter Zijlstra 已提交
2497 2498 2499 2500 2501 2502 2503 2504 2505 2506 2507 2508 2509 2510 2511

/*
 * 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;
}
2512
EXPORT_SYMBOL_GPL(perf_event_refresh);
2513

2514 2515 2516
static void ctx_sched_out(struct perf_event_context *ctx,
			  struct perf_cpu_context *cpuctx,
			  enum event_type_t event_type)
2517
{
2518
	int is_active = ctx->is_active;
P
Peter Zijlstra 已提交
2519
	struct perf_event *event;
2520

P
Peter Zijlstra 已提交
2521
	lockdep_assert_held(&ctx->lock);
2522

2523 2524 2525 2526 2527 2528 2529
	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);
2530
		return;
2531 2532
	}

2533
	ctx->is_active &= ~event_type;
2534 2535 2536
	if (!(ctx->is_active & EVENT_ALL))
		ctx->is_active = 0;

2537 2538 2539 2540 2541
	if (ctx->task) {
		WARN_ON_ONCE(cpuctx->task_ctx != ctx);
		if (!ctx->is_active)
			cpuctx->task_ctx = NULL;
	}
2542

2543 2544 2545 2546 2547 2548 2549 2550 2551 2552
	/*
	 * 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.
	 */
2553 2554 2555 2556 2557 2558
	if (is_active & EVENT_TIME) {
		/* update (and stop) ctx time */
		update_context_time(ctx);
		update_cgrp_time_from_cpuctx(cpuctx);
	}

2559 2560
	is_active ^= ctx->is_active; /* changed bits */

2561
	if (!ctx->nr_active || !(is_active & EVENT_ALL))
2562
		return;
2563

P
Peter Zijlstra 已提交
2564
	perf_pmu_disable(ctx->pmu);
2565
	if (is_active & EVENT_PINNED) {
2566 2567
		list_for_each_entry(event, &ctx->pinned_groups, group_entry)
			group_sched_out(event, cpuctx, ctx);
P
Peter Zijlstra 已提交
2568
	}
2569

2570
	if (is_active & EVENT_FLEXIBLE) {
2571
		list_for_each_entry(event, &ctx->flexible_groups, group_entry)
2572
			group_sched_out(event, cpuctx, ctx);
P
Peter Zijlstra 已提交
2573
	}
P
Peter Zijlstra 已提交
2574
	perf_pmu_enable(ctx->pmu);
2575 2576
}

2577
/*
2578 2579 2580 2581 2582 2583
 * 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().
2584
 */
2585 2586
static int context_equiv(struct perf_event_context *ctx1,
			 struct perf_event_context *ctx2)
2587
{
2588 2589 2590
	lockdep_assert_held(&ctx1->lock);
	lockdep_assert_held(&ctx2->lock);

2591 2592 2593 2594 2595 2596 2597 2598 2599 2600 2601 2602 2603 2604 2605 2606 2607 2608 2609 2610 2611 2612
	/* 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;
2613 2614
}

2615 2616
static void __perf_event_sync_stat(struct perf_event *event,
				     struct perf_event *next_event)
2617 2618 2619
{
	u64 value;

2620
	if (!event->attr.inherit_stat)
2621 2622 2623
		return;

	/*
2624
	 * Update the event value, we cannot use perf_event_read()
2625 2626
	 * because we're in the middle of a context switch and have IRQs
	 * disabled, which upsets smp_call_function_single(), however
2627
	 * we know the event must be on the current CPU, therefore we
2628 2629
	 * don't need to use it.
	 */
2630 2631
	switch (event->state) {
	case PERF_EVENT_STATE_ACTIVE:
2632 2633
		event->pmu->read(event);
		/* fall-through */
2634

2635 2636
	case PERF_EVENT_STATE_INACTIVE:
		update_event_times(event);
2637 2638 2639 2640 2641 2642 2643
		break;

	default:
		break;
	}

	/*
2644
	 * In order to keep per-task stats reliable we need to flip the event
2645 2646
	 * values when we flip the contexts.
	 */
2647 2648 2649
	value = local64_read(&next_event->count);
	value = local64_xchg(&event->count, value);
	local64_set(&next_event->count, value);
2650

2651 2652
	swap(event->total_time_enabled, next_event->total_time_enabled);
	swap(event->total_time_running, next_event->total_time_running);
2653

2654
	/*
2655
	 * Since we swizzled the values, update the user visible data too.
2656
	 */
2657 2658
	perf_event_update_userpage(event);
	perf_event_update_userpage(next_event);
2659 2660
}

2661 2662
static void perf_event_sync_stat(struct perf_event_context *ctx,
				   struct perf_event_context *next_ctx)
2663
{
2664
	struct perf_event *event, *next_event;
2665 2666 2667 2668

	if (!ctx->nr_stat)
		return;

2669 2670
	update_context_time(ctx);

2671 2672
	event = list_first_entry(&ctx->event_list,
				   struct perf_event, event_entry);
2673

2674 2675
	next_event = list_first_entry(&next_ctx->event_list,
					struct perf_event, event_entry);
2676

2677 2678
	while (&event->event_entry != &ctx->event_list &&
	       &next_event->event_entry != &next_ctx->event_list) {
2679

2680
		__perf_event_sync_stat(event, next_event);
2681

2682 2683
		event = list_next_entry(event, event_entry);
		next_event = list_next_entry(next_event, event_entry);
2684 2685 2686
	}
}

2687 2688
static void perf_event_context_sched_out(struct task_struct *task, int ctxn,
					 struct task_struct *next)
T
Thomas Gleixner 已提交
2689
{
P
Peter Zijlstra 已提交
2690
	struct perf_event_context *ctx = task->perf_event_ctxp[ctxn];
2691
	struct perf_event_context *next_ctx;
2692
	struct perf_event_context *parent, *next_parent;
P
Peter Zijlstra 已提交
2693
	struct perf_cpu_context *cpuctx;
2694
	int do_switch = 1;
T
Thomas Gleixner 已提交
2695

P
Peter Zijlstra 已提交
2696 2697
	if (likely(!ctx))
		return;
2698

P
Peter Zijlstra 已提交
2699 2700
	cpuctx = __get_cpu_context(ctx);
	if (!cpuctx->task_ctx)
T
Thomas Gleixner 已提交
2701 2702
		return;

2703
	rcu_read_lock();
P
Peter Zijlstra 已提交
2704
	next_ctx = next->perf_event_ctxp[ctxn];
2705 2706 2707 2708 2709 2710 2711
	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. */
2712
	if (!parent && !next_parent)
2713 2714 2715
		goto unlock;

	if (next_parent == ctx || next_ctx == parent || next_parent == parent) {
2716 2717 2718 2719 2720 2721 2722 2723 2724
		/*
		 * 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.
		 */
2725 2726
		raw_spin_lock(&ctx->lock);
		raw_spin_lock_nested(&next_ctx->lock, SINGLE_DEPTH_NESTING);
2727
		if (context_equiv(ctx, next_ctx)) {
2728 2729
			WRITE_ONCE(ctx->task, next);
			WRITE_ONCE(next_ctx->task, task);
2730 2731 2732

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

2733 2734 2735 2736 2737 2738 2739 2740 2741 2742
			/*
			 * 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);

2743
			do_switch = 0;
2744

2745
			perf_event_sync_stat(ctx, next_ctx);
2746
		}
2747 2748
		raw_spin_unlock(&next_ctx->lock);
		raw_spin_unlock(&ctx->lock);
2749
	}
2750
unlock:
2751
	rcu_read_unlock();
2752

2753
	if (do_switch) {
2754
		raw_spin_lock(&ctx->lock);
P
Peter Zijlstra 已提交
2755
		task_ctx_sched_out(cpuctx, ctx);
2756
		raw_spin_unlock(&ctx->lock);
2757
	}
T
Thomas Gleixner 已提交
2758 2759
}

2760 2761 2762 2763 2764 2765 2766 2767 2768 2769 2770 2771 2772 2773 2774 2775 2776 2777 2778 2779 2780 2781 2782 2783 2784 2785 2786 2787 2788 2789 2790 2791 2792 2793 2794 2795 2796 2797 2798 2799 2800 2801 2802 2803 2804 2805 2806 2807 2808 2809
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);
}

2810 2811 2812
static void perf_event_switch(struct task_struct *task,
			      struct task_struct *next_prev, bool sched_in);

P
Peter Zijlstra 已提交
2813 2814 2815 2816 2817 2818 2819 2820 2821 2822 2823 2824 2825 2826
#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.
 */
2827 2828
void __perf_event_task_sched_out(struct task_struct *task,
				 struct task_struct *next)
P
Peter Zijlstra 已提交
2829 2830 2831
{
	int ctxn;

2832 2833 2834
	if (__this_cpu_read(perf_sched_cb_usages))
		perf_pmu_sched_task(task, next, false);

2835 2836 2837
	if (atomic_read(&nr_switch_events))
		perf_event_switch(task, next, false);

P
Peter Zijlstra 已提交
2838 2839
	for_each_task_context_nr(ctxn)
		perf_event_context_sched_out(task, ctxn, next);
S
Stephane Eranian 已提交
2840 2841 2842 2843 2844 2845

	/*
	 * 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
	 */
2846
	if (atomic_read(this_cpu_ptr(&perf_cgroup_events)))
2847
		perf_cgroup_sched_out(task, next);
P
Peter Zijlstra 已提交
2848 2849
}

2850 2851 2852 2853 2854 2855 2856
/*
 * 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);
2857 2858
}

2859
static void
2860
ctx_pinned_sched_in(struct perf_event_context *ctx,
2861
		    struct perf_cpu_context *cpuctx)
T
Thomas Gleixner 已提交
2862
{
2863
	struct perf_event *event;
T
Thomas Gleixner 已提交
2864

2865 2866
	list_for_each_entry(event, &ctx->pinned_groups, group_entry) {
		if (event->state <= PERF_EVENT_STATE_OFF)
2867
			continue;
2868
		if (!event_filter_match(event))
2869 2870
			continue;

S
Stephane Eranian 已提交
2871 2872 2873 2874
		/* may need to reset tstamp_enabled */
		if (is_cgroup_event(event))
			perf_cgroup_mark_enabled(event, ctx);

2875
		if (group_can_go_on(event, cpuctx, 1))
2876
			group_sched_in(event, cpuctx, ctx);
2877 2878 2879 2880 2881

		/*
		 * If this pinned group hasn't been scheduled,
		 * put it in error state.
		 */
2882 2883 2884
		if (event->state == PERF_EVENT_STATE_INACTIVE) {
			update_group_times(event);
			event->state = PERF_EVENT_STATE_ERROR;
2885
		}
2886
	}
2887 2888 2889 2890
}

static void
ctx_flexible_sched_in(struct perf_event_context *ctx,
2891
		      struct perf_cpu_context *cpuctx)
2892 2893 2894
{
	struct perf_event *event;
	int can_add_hw = 1;
2895

2896 2897 2898
	list_for_each_entry(event, &ctx->flexible_groups, group_entry) {
		/* Ignore events in OFF or ERROR state */
		if (event->state <= PERF_EVENT_STATE_OFF)
2899
			continue;
2900 2901
		/*
		 * Listen to the 'cpu' scheduling filter constraint
2902
		 * of events:
2903
		 */
2904
		if (!event_filter_match(event))
T
Thomas Gleixner 已提交
2905 2906
			continue;

S
Stephane Eranian 已提交
2907 2908 2909 2910
		/* may need to reset tstamp_enabled */
		if (is_cgroup_event(event))
			perf_cgroup_mark_enabled(event, ctx);

P
Peter Zijlstra 已提交
2911
		if (group_can_go_on(event, cpuctx, can_add_hw)) {
2912
			if (group_sched_in(event, cpuctx, ctx))
2913
				can_add_hw = 0;
P
Peter Zijlstra 已提交
2914
		}
T
Thomas Gleixner 已提交
2915
	}
2916 2917 2918 2919 2920
}

static void
ctx_sched_in(struct perf_event_context *ctx,
	     struct perf_cpu_context *cpuctx,
S
Stephane Eranian 已提交
2921 2922
	     enum event_type_t event_type,
	     struct task_struct *task)
2923
{
2924
	int is_active = ctx->is_active;
P
Peter Zijlstra 已提交
2925 2926 2927
	u64 now;

	lockdep_assert_held(&ctx->lock);
S
Stephane Eranian 已提交
2928

2929
	if (likely(!ctx->nr_events))
2930
		return;
2931

2932
	ctx->is_active |= (event_type | EVENT_TIME);
2933 2934 2935 2936 2937 2938 2939
	if (ctx->task) {
		if (!is_active)
			cpuctx->task_ctx = ctx;
		else
			WARN_ON_ONCE(cpuctx->task_ctx != ctx);
	}

2940 2941 2942 2943 2944 2945 2946 2947 2948
	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);
	}

2949 2950 2951 2952
	/*
	 * First go through the list and put on any pinned groups
	 * in order to give them the best chance of going on.
	 */
2953
	if (is_active & EVENT_PINNED)
2954
		ctx_pinned_sched_in(ctx, cpuctx);
2955 2956

	/* Then walk through the lower prio flexible groups */
2957
	if (is_active & EVENT_FLEXIBLE)
2958
		ctx_flexible_sched_in(ctx, cpuctx);
2959 2960
}

2961
static void cpu_ctx_sched_in(struct perf_cpu_context *cpuctx,
S
Stephane Eranian 已提交
2962 2963
			     enum event_type_t event_type,
			     struct task_struct *task)
2964 2965 2966
{
	struct perf_event_context *ctx = &cpuctx->ctx;

S
Stephane Eranian 已提交
2967
	ctx_sched_in(ctx, cpuctx, event_type, task);
2968 2969
}

S
Stephane Eranian 已提交
2970 2971
static void perf_event_context_sched_in(struct perf_event_context *ctx,
					struct task_struct *task)
2972
{
P
Peter Zijlstra 已提交
2973
	struct perf_cpu_context *cpuctx;
2974

P
Peter Zijlstra 已提交
2975
	cpuctx = __get_cpu_context(ctx);
2976 2977 2978
	if (cpuctx->task_ctx == ctx)
		return;

2979
	perf_ctx_lock(cpuctx, ctx);
P
Peter Zijlstra 已提交
2980
	perf_pmu_disable(ctx->pmu);
2981 2982 2983 2984 2985 2986
	/*
	 * 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);
2987
	perf_event_sched_in(cpuctx, ctx, task);
2988 2989
	perf_pmu_enable(ctx->pmu);
	perf_ctx_unlock(cpuctx, ctx);
2990 2991
}

P
Peter Zijlstra 已提交
2992 2993 2994 2995 2996 2997 2998 2999 3000 3001 3002
/*
 * 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.
 */
3003 3004
void __perf_event_task_sched_in(struct task_struct *prev,
				struct task_struct *task)
P
Peter Zijlstra 已提交
3005 3006 3007 3008
{
	struct perf_event_context *ctx;
	int ctxn;

3009 3010 3011 3012 3013 3014 3015 3016 3017 3018
	/*
	 * 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
3019 3020 3021 3022 3023
	for_each_task_context_nr(ctxn) {
		ctx = task->perf_event_ctxp[ctxn];
		if (likely(!ctx))
			continue;

S
Stephane Eranian 已提交
3024
		perf_event_context_sched_in(ctx, task);
P
Peter Zijlstra 已提交
3025
	}
3026

3027 3028 3029
	if (atomic_read(&nr_switch_events))
		perf_event_switch(task, prev, true);

3030 3031
	if (__this_cpu_read(perf_sched_cb_usages))
		perf_pmu_sched_task(prev, task, true);
3032 3033
}

3034 3035 3036 3037 3038 3039 3040 3041 3042 3043 3044 3045 3046 3047 3048 3049 3050 3051 3052 3053 3054 3055 3056 3057 3058 3059 3060
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.
	 */
3061
#define REDUCE_FLS(a, b)		\
3062 3063 3064 3065 3066 3067 3068 3069 3070 3071 3072 3073 3074 3075 3076 3077 3078 3079 3080 3081 3082 3083 3084 3085 3086 3087 3088 3089 3090 3091 3092 3093 3094 3095 3096 3097 3098 3099 3100
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;
	}

3101 3102 3103
	if (!divisor)
		return dividend;

3104 3105 3106
	return div64_u64(dividend, divisor);
}

3107 3108 3109
static DEFINE_PER_CPU(int, perf_throttled_count);
static DEFINE_PER_CPU(u64, perf_throttled_seq);

3110
static void perf_adjust_period(struct perf_event *event, u64 nsec, u64 count, bool disable)
3111
{
3112
	struct hw_perf_event *hwc = &event->hw;
3113
	s64 period, sample_period;
3114 3115
	s64 delta;

3116
	period = perf_calculate_period(event, nsec, count);
3117 3118 3119 3120 3121 3122 3123 3124 3125 3126

	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;
3127

3128
	if (local64_read(&hwc->period_left) > 8*sample_period) {
3129 3130 3131
		if (disable)
			event->pmu->stop(event, PERF_EF_UPDATE);

3132
		local64_set(&hwc->period_left, 0);
3133 3134 3135

		if (disable)
			event->pmu->start(event, PERF_EF_RELOAD);
3136
	}
3137 3138
}

3139 3140 3141 3142 3143 3144 3145
/*
 * 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)
3146
{
3147 3148
	struct perf_event *event;
	struct hw_perf_event *hwc;
3149
	u64 now, period = TICK_NSEC;
3150
	s64 delta;
3151

3152 3153 3154 3155 3156 3157
	/*
	 * 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))
3158 3159
		return;

3160
	raw_spin_lock(&ctx->lock);
3161
	perf_pmu_disable(ctx->pmu);
3162

3163
	list_for_each_entry_rcu(event, &ctx->event_list, event_entry) {
3164
		if (event->state != PERF_EVENT_STATE_ACTIVE)
3165 3166
			continue;

3167
		if (!event_filter_match(event))
3168 3169
			continue;

3170 3171
		perf_pmu_disable(event->pmu);

3172
		hwc = &event->hw;
3173

3174
		if (hwc->interrupts == MAX_INTERRUPTS) {
3175
			hwc->interrupts = 0;
3176
			perf_log_throttle(event, 1);
P
Peter Zijlstra 已提交
3177
			event->pmu->start(event, 0);
3178 3179
		}

3180
		if (!event->attr.freq || !event->attr.sample_freq)
3181
			goto next;
3182

3183 3184 3185 3186 3187
		/*
		 * stop the event and update event->count
		 */
		event->pmu->stop(event, PERF_EF_UPDATE);

3188
		now = local64_read(&event->count);
3189 3190
		delta = now - hwc->freq_count_stamp;
		hwc->freq_count_stamp = now;
3191

3192 3193 3194
		/*
		 * restart the event
		 * reload only if value has changed
3195 3196 3197
		 * we have stopped the event so tell that
		 * to perf_adjust_period() to avoid stopping it
		 * twice.
3198
		 */
3199
		if (delta > 0)
3200
			perf_adjust_period(event, period, delta, false);
3201 3202

		event->pmu->start(event, delta > 0 ? PERF_EF_RELOAD : 0);
3203 3204
	next:
		perf_pmu_enable(event->pmu);
3205
	}
3206

3207
	perf_pmu_enable(ctx->pmu);
3208
	raw_spin_unlock(&ctx->lock);
3209 3210
}

3211
/*
3212
 * Round-robin a context's events:
3213
 */
3214
static void rotate_ctx(struct perf_event_context *ctx)
T
Thomas Gleixner 已提交
3215
{
3216 3217 3218 3219 3220 3221
	/*
	 * 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);
3222 3223
}

3224
static int perf_rotate_context(struct perf_cpu_context *cpuctx)
3225
{
P
Peter Zijlstra 已提交
3226
	struct perf_event_context *ctx = NULL;
3227
	int rotate = 0;
3228

3229 3230 3231 3232
	if (cpuctx->ctx.nr_events) {
		if (cpuctx->ctx.nr_events != cpuctx->ctx.nr_active)
			rotate = 1;
	}
3233

P
Peter Zijlstra 已提交
3234
	ctx = cpuctx->task_ctx;
3235 3236 3237 3238
	if (ctx && ctx->nr_events) {
		if (ctx->nr_events != ctx->nr_active)
			rotate = 1;
	}
3239

3240
	if (!rotate)
3241 3242
		goto done;

3243
	perf_ctx_lock(cpuctx, cpuctx->task_ctx);
P
Peter Zijlstra 已提交
3244
	perf_pmu_disable(cpuctx->ctx.pmu);
3245

3246 3247 3248
	cpu_ctx_sched_out(cpuctx, EVENT_FLEXIBLE);
	if (ctx)
		ctx_sched_out(ctx, cpuctx, EVENT_FLEXIBLE);
T
Thomas Gleixner 已提交
3249

3250 3251 3252
	rotate_ctx(&cpuctx->ctx);
	if (ctx)
		rotate_ctx(ctx);
3253

3254
	perf_event_sched_in(cpuctx, ctx, current);
3255

3256 3257
	perf_pmu_enable(cpuctx->ctx.pmu);
	perf_ctx_unlock(cpuctx, cpuctx->task_ctx);
3258
done:
3259 3260

	return rotate;
3261 3262 3263 3264
}

void perf_event_task_tick(void)
{
3265 3266
	struct list_head *head = this_cpu_ptr(&active_ctx_list);
	struct perf_event_context *ctx, *tmp;
3267
	int throttled;
3268

3269 3270
	WARN_ON(!irqs_disabled());

3271 3272
	__this_cpu_inc(perf_throttled_seq);
	throttled = __this_cpu_xchg(perf_throttled_count, 0);
3273
	tick_dep_clear_cpu(smp_processor_id(), TICK_DEP_BIT_PERF_EVENTS);
3274

3275
	list_for_each_entry_safe(ctx, tmp, head, active_ctx_list)
3276
		perf_adjust_freq_unthr_context(ctx, throttled);
T
Thomas Gleixner 已提交
3277 3278
}

3279 3280 3281 3282 3283 3284 3285 3286 3287 3288
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;

3289
	__perf_event_mark_enabled(event);
3290 3291 3292 3293

	return 1;
}

3294
/*
3295
 * Enable all of a task's events that have been marked enable-on-exec.
3296 3297
 * This expects task == current.
 */
3298
static void perf_event_enable_on_exec(int ctxn)
3299
{
3300
	struct perf_event_context *ctx, *clone_ctx = NULL;
3301
	struct perf_cpu_context *cpuctx;
3302
	struct perf_event *event;
3303 3304 3305 3306
	unsigned long flags;
	int enabled = 0;

	local_irq_save(flags);
3307
	ctx = current->perf_event_ctxp[ctxn];
3308
	if (!ctx || !ctx->nr_events)
3309 3310
		goto out;

3311 3312
	cpuctx = __get_cpu_context(ctx);
	perf_ctx_lock(cpuctx, ctx);
3313
	ctx_sched_out(ctx, cpuctx, EVENT_TIME);
3314 3315
	list_for_each_entry(event, &ctx->event_list, event_entry)
		enabled |= event_enable_on_exec(event, ctx);
3316 3317

	/*
3318
	 * Unclone and reschedule this context if we enabled any event.
3319
	 */
3320
	if (enabled) {
3321
		clone_ctx = unclone_ctx(ctx);
3322 3323 3324
		ctx_resched(cpuctx, ctx);
	}
	perf_ctx_unlock(cpuctx, ctx);
3325

P
Peter Zijlstra 已提交
3326
out:
3327
	local_irq_restore(flags);
3328 3329 3330

	if (clone_ctx)
		put_ctx(clone_ctx);
3331 3332
}

3333 3334 3335
struct perf_read_data {
	struct perf_event *event;
	bool group;
3336
	int ret;
3337 3338
};

T
Thomas Gleixner 已提交
3339
/*
3340
 * Cross CPU call to read the hardware event
T
Thomas Gleixner 已提交
3341
 */
3342
static void __perf_event_read(void *info)
T
Thomas Gleixner 已提交
3343
{
3344 3345
	struct perf_read_data *data = info;
	struct perf_event *sub, *event = data->event;
3346
	struct perf_event_context *ctx = event->ctx;
P
Peter Zijlstra 已提交
3347
	struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
3348
	struct pmu *pmu = event->pmu;
I
Ingo Molnar 已提交
3349

3350 3351 3352 3353
	/*
	 * 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
3354 3355
	 * event->count would have been updated to a recent sample
	 * when the event was scheduled out.
3356 3357 3358 3359
	 */
	if (ctx->task && cpuctx->task_ctx != ctx)
		return;

3360
	raw_spin_lock(&ctx->lock);
S
Stephane Eranian 已提交
3361
	if (ctx->is_active) {
3362
		update_context_time(ctx);
S
Stephane Eranian 已提交
3363 3364
		update_cgrp_time_from_event(event);
	}
3365

3366
	update_event_times(event);
3367 3368
	if (event->state != PERF_EVENT_STATE_ACTIVE)
		goto unlock;
3369

3370 3371 3372
	if (!data->group) {
		pmu->read(event);
		data->ret = 0;
3373
		goto unlock;
3374 3375 3376 3377 3378
	}

	pmu->start_txn(pmu, PERF_PMU_TXN_READ);

	pmu->read(event);
3379 3380 3381

	list_for_each_entry(sub, &event->sibling_list, group_entry) {
		update_event_times(sub);
3382 3383 3384 3385 3386
		if (sub->state == PERF_EVENT_STATE_ACTIVE) {
			/*
			 * Use sibling's PMU rather than @event's since
			 * sibling could be on different (eg: software) PMU.
			 */
3387
			sub->pmu->read(sub);
3388
		}
3389
	}
3390 3391

	data->ret = pmu->commit_txn(pmu);
3392 3393

unlock:
3394
	raw_spin_unlock(&ctx->lock);
T
Thomas Gleixner 已提交
3395 3396
}

P
Peter Zijlstra 已提交
3397 3398
static inline u64 perf_event_count(struct perf_event *event)
{
3399 3400 3401 3402
	if (event->pmu->count)
		return event->pmu->count(event);

	return __perf_event_count(event);
P
Peter Zijlstra 已提交
3403 3404
}

3405 3406 3407 3408 3409 3410 3411 3412 3413 3414 3415 3416 3417 3418 3419 3420 3421 3422 3423 3424 3425 3426 3427 3428 3429 3430 3431 3432 3433 3434 3435 3436 3437 3438 3439 3440 3441 3442 3443 3444 3445 3446 3447 3448 3449 3450 3451 3452 3453 3454 3455 3456 3457
/*
 * 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;
}

3458
static int perf_event_read(struct perf_event *event, bool group)
T
Thomas Gleixner 已提交
3459
{
3460 3461
	int ret = 0;

T
Thomas Gleixner 已提交
3462
	/*
3463 3464
	 * If event is enabled and currently active on a CPU, update the
	 * value in the event structure:
T
Thomas Gleixner 已提交
3465
	 */
3466
	if (event->state == PERF_EVENT_STATE_ACTIVE) {
3467 3468 3469
		struct perf_read_data data = {
			.event = event,
			.group = group,
3470
			.ret = 0,
3471
		};
3472
		smp_call_function_single(event->oncpu,
3473
					 __perf_event_read, &data, 1);
3474
		ret = data.ret;
3475
	} else if (event->state == PERF_EVENT_STATE_INACTIVE) {
P
Peter Zijlstra 已提交
3476 3477 3478
		struct perf_event_context *ctx = event->ctx;
		unsigned long flags;

3479
		raw_spin_lock_irqsave(&ctx->lock, flags);
3480 3481 3482 3483 3484
		/*
		 * 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
3485
		if (ctx->is_active) {
3486
			update_context_time(ctx);
S
Stephane Eranian 已提交
3487 3488
			update_cgrp_time_from_event(event);
		}
3489 3490 3491 3492
		if (group)
			update_group_times(event);
		else
			update_event_times(event);
3493
		raw_spin_unlock_irqrestore(&ctx->lock, flags);
T
Thomas Gleixner 已提交
3494
	}
3495 3496

	return ret;
T
Thomas Gleixner 已提交
3497 3498
}

3499
/*
3500
 * Initialize the perf_event context in a task_struct:
3501
 */
3502
static void __perf_event_init_context(struct perf_event_context *ctx)
3503
{
3504
	raw_spin_lock_init(&ctx->lock);
3505
	mutex_init(&ctx->mutex);
3506
	INIT_LIST_HEAD(&ctx->active_ctx_list);
3507 3508
	INIT_LIST_HEAD(&ctx->pinned_groups);
	INIT_LIST_HEAD(&ctx->flexible_groups);
3509 3510
	INIT_LIST_HEAD(&ctx->event_list);
	atomic_set(&ctx->refcount, 1);
3511 3512 3513 3514 3515 3516 3517 3518 3519 3520 3521 3522 3523 3524 3525
}

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
3526
	}
3527 3528 3529
	ctx->pmu = pmu;

	return ctx;
3530 3531
}

3532 3533 3534 3535
static struct task_struct *
find_lively_task_by_vpid(pid_t vpid)
{
	struct task_struct *task;
T
Thomas Gleixner 已提交
3536 3537

	rcu_read_lock();
3538
	if (!vpid)
T
Thomas Gleixner 已提交
3539 3540
		task = current;
	else
3541
		task = find_task_by_vpid(vpid);
T
Thomas Gleixner 已提交
3542 3543 3544 3545 3546 3547 3548
	if (task)
		get_task_struct(task);
	rcu_read_unlock();

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

3549 3550 3551
	return task;
}

3552 3553 3554
/*
 * Returns a matching context with refcount and pincount.
 */
P
Peter Zijlstra 已提交
3555
static struct perf_event_context *
3556 3557
find_get_context(struct pmu *pmu, struct task_struct *task,
		struct perf_event *event)
T
Thomas Gleixner 已提交
3558
{
3559
	struct perf_event_context *ctx, *clone_ctx = NULL;
3560
	struct perf_cpu_context *cpuctx;
3561
	void *task_ctx_data = NULL;
3562
	unsigned long flags;
P
Peter Zijlstra 已提交
3563
	int ctxn, err;
3564
	int cpu = event->cpu;
T
Thomas Gleixner 已提交
3565

3566
	if (!task) {
3567
		/* Must be root to operate on a CPU event: */
3568
		if (perf_paranoid_cpu() && !capable(CAP_SYS_ADMIN))
T
Thomas Gleixner 已提交
3569 3570 3571
			return ERR_PTR(-EACCES);

		/*
3572
		 * We could be clever and allow to attach a event to an
T
Thomas Gleixner 已提交
3573 3574 3575
		 * offline CPU and activate it when the CPU comes up, but
		 * that's for later.
		 */
3576
		if (!cpu_online(cpu))
T
Thomas Gleixner 已提交
3577 3578
			return ERR_PTR(-ENODEV);

P
Peter Zijlstra 已提交
3579
		cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
T
Thomas Gleixner 已提交
3580
		ctx = &cpuctx->ctx;
3581
		get_ctx(ctx);
3582
		++ctx->pin_count;
T
Thomas Gleixner 已提交
3583 3584 3585 3586

		return ctx;
	}

P
Peter Zijlstra 已提交
3587 3588 3589 3590 3591
	err = -EINVAL;
	ctxn = pmu->task_ctx_nr;
	if (ctxn < 0)
		goto errout;

3592 3593 3594 3595 3596 3597 3598 3599
	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
3600
retry:
P
Peter Zijlstra 已提交
3601
	ctx = perf_lock_task_context(task, ctxn, &flags);
3602
	if (ctx) {
3603
		clone_ctx = unclone_ctx(ctx);
3604
		++ctx->pin_count;
3605 3606 3607 3608 3609

		if (task_ctx_data && !ctx->task_ctx_data) {
			ctx->task_ctx_data = task_ctx_data;
			task_ctx_data = NULL;
		}
3610
		raw_spin_unlock_irqrestore(&ctx->lock, flags);
3611 3612 3613

		if (clone_ctx)
			put_ctx(clone_ctx);
3614
	} else {
3615
		ctx = alloc_perf_context(pmu, task);
3616 3617 3618
		err = -ENOMEM;
		if (!ctx)
			goto errout;
3619

3620 3621 3622 3623 3624
		if (task_ctx_data) {
			ctx->task_ctx_data = task_ctx_data;
			task_ctx_data = NULL;
		}

3625 3626 3627 3628 3629 3630 3631 3632 3633 3634
		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;
3635
		else {
3636
			get_ctx(ctx);
3637
			++ctx->pin_count;
3638
			rcu_assign_pointer(task->perf_event_ctxp[ctxn], ctx);
3639
		}
3640 3641 3642
		mutex_unlock(&task->perf_event_mutex);

		if (unlikely(err)) {
3643
			put_ctx(ctx);
3644 3645 3646 3647

			if (err == -EAGAIN)
				goto retry;
			goto errout;
3648 3649 3650
		}
	}

3651
	kfree(task_ctx_data);
T
Thomas Gleixner 已提交
3652
	return ctx;
3653

P
Peter Zijlstra 已提交
3654
errout:
3655
	kfree(task_ctx_data);
3656
	return ERR_PTR(err);
T
Thomas Gleixner 已提交
3657 3658
}

L
Li Zefan 已提交
3659
static void perf_event_free_filter(struct perf_event *event);
3660
static void perf_event_free_bpf_prog(struct perf_event *event);
L
Li Zefan 已提交
3661

3662
static void free_event_rcu(struct rcu_head *head)
P
Peter Zijlstra 已提交
3663
{
3664
	struct perf_event *event;
P
Peter Zijlstra 已提交
3665

3666 3667 3668
	event = container_of(head, struct perf_event, rcu_head);
	if (event->ns)
		put_pid_ns(event->ns);
L
Li Zefan 已提交
3669
	perf_event_free_filter(event);
3670
	kfree(event);
P
Peter Zijlstra 已提交
3671 3672
}

3673 3674
static void ring_buffer_attach(struct perf_event *event,
			       struct ring_buffer *rb);
3675

3676 3677 3678 3679 3680 3681 3682 3683 3684 3685 3686 3687 3688 3689 3690 3691 3692 3693 3694 3695
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);
}

static void unaccount_pmu_sb_event(struct perf_event *event)
{
	if (event->parent)
		return;

	if (event->attach_state & PERF_ATTACH_TASK)
		return;

	detach_sb_event(event);
}

3696
static void unaccount_event_cpu(struct perf_event *event, int cpu)
3697
{
3698 3699 3700 3701 3702 3703
	if (event->parent)
		return;

	if (is_cgroup_event(event))
		atomic_dec(&per_cpu(perf_cgroup_events, cpu));
}
3704

3705 3706 3707 3708 3709 3710 3711 3712 3713 3714 3715 3716 3717 3718 3719 3720 3721 3722 3723 3724 3725 3726
#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);
}

3727 3728
static void unaccount_event(struct perf_event *event)
{
3729 3730
	bool dec = false;

3731 3732 3733 3734
	if (event->parent)
		return;

	if (event->attach_state & PERF_ATTACH_TASK)
3735
		dec = true;
3736 3737 3738 3739 3740 3741
	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);
3742
	if (event->attr.freq)
3743
		unaccount_freq_event();
3744
	if (event->attr.context_switch) {
3745
		dec = true;
3746 3747
		atomic_dec(&nr_switch_events);
	}
3748
	if (is_cgroup_event(event))
3749
		dec = true;
3750
	if (has_branch_stack(event))
3751 3752
		dec = true;

3753 3754 3755 3756
	if (dec) {
		if (!atomic_add_unless(&perf_sched_count, -1, 1))
			schedule_delayed_work(&perf_sched_work, HZ);
	}
3757 3758

	unaccount_event_cpu(event, event->cpu);
3759 3760

	unaccount_pmu_sb_event(event);
3761
}
3762

3763 3764 3765 3766 3767 3768 3769 3770
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);
}

3771 3772 3773 3774 3775 3776 3777 3778 3779 3780
/*
 * 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
3781
 * _free_event()), the latter -- before the first perf_install_in_context().
3782 3783 3784 3785 3786 3787 3788 3789 3790 3791 3792 3793 3794 3795 3796 3797 3798 3799 3800 3801 3802 3803 3804 3805 3806 3807 3808 3809 3810 3811 3812 3813 3814 3815 3816 3817 3818 3819 3820 3821 3822 3823 3824 3825 3826 3827 3828 3829 3830 3831 3832 3833 3834 3835 3836 3837 3838 3839 3840 3841 3842 3843 3844 3845 3846 3847 3848 3849 3850 3851 3852 3853 3854 3855
 */
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;
}

3856 3857 3858
static void perf_addr_filters_splice(struct perf_event *event,
				       struct list_head *head);

P
Peter Zijlstra 已提交
3859
static void _free_event(struct perf_event *event)
3860
{
3861
	irq_work_sync(&event->pending);
3862

3863
	unaccount_event(event);
3864

3865
	if (event->rb) {
3866 3867 3868 3869 3870 3871 3872
		/*
		 * 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);
3873
		ring_buffer_attach(event, NULL);
3874
		mutex_unlock(&event->mmap_mutex);
3875 3876
	}

S
Stephane Eranian 已提交
3877 3878 3879
	if (is_cgroup_event(event))
		perf_detach_cgroup(event);

P
Peter Zijlstra 已提交
3880 3881 3882 3883 3884 3885
	if (!event->parent) {
		if (event->attr.sample_type & PERF_SAMPLE_CALLCHAIN)
			put_callchain_buffers();
	}

	perf_event_free_bpf_prog(event);
3886 3887
	perf_addr_filters_splice(event, NULL);
	kfree(event->addr_filters_offs);
P
Peter Zijlstra 已提交
3888 3889 3890 3891 3892 3893 3894 3895 3896 3897 3898 3899 3900

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

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

	if (event->pmu) {
		exclusive_event_destroy(event);
		module_put(event->pmu->module);
	}

	call_rcu(&event->rcu_head, free_event_rcu);
3901 3902
}

P
Peter Zijlstra 已提交
3903 3904 3905 3906 3907
/*
 * 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
3908
{
P
Peter Zijlstra 已提交
3909 3910 3911 3912 3913 3914
	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
3915

P
Peter Zijlstra 已提交
3916
	_free_event(event);
T
Thomas Gleixner 已提交
3917 3918
}

3919
/*
3920
 * Remove user event from the owner task.
3921
 */
3922
static void perf_remove_from_owner(struct perf_event *event)
3923
{
P
Peter Zijlstra 已提交
3924
	struct task_struct *owner;
3925

P
Peter Zijlstra 已提交
3926 3927
	rcu_read_lock();
	/*
3928 3929 3930
	 * 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
3931 3932
	 * owner->perf_event_mutex.
	 */
3933
	owner = lockless_dereference(event->owner);
P
Peter Zijlstra 已提交
3934 3935 3936 3937 3938 3939 3940 3941 3942 3943 3944
	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
3945 3946 3947 3948 3949 3950 3951 3952 3953 3954
		/*
		 * 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
3955 3956 3957 3958 3959 3960
		/*
		 * 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.
		 */
3961
		if (event->owner) {
P
Peter Zijlstra 已提交
3962
			list_del_init(&event->owner_entry);
3963 3964
			smp_store_release(&event->owner, NULL);
		}
P
Peter Zijlstra 已提交
3965 3966 3967
		mutex_unlock(&owner->perf_event_mutex);
		put_task_struct(owner);
	}
3968 3969 3970 3971 3972 3973 3974
}

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

3975 3976 3977 3978 3979 3980 3981 3982 3983 3984
	_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)
{
3985
	struct perf_event_context *ctx = event->ctx;
3986 3987
	struct perf_event *child, *tmp;

3988 3989 3990 3991 3992 3993 3994 3995 3996 3997
	/*
	 * 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;
	}

3998 3999
	if (!is_kernel_event(event))
		perf_remove_from_owner(event);
P
Peter Zijlstra 已提交
4000

4001
	ctx = perf_event_ctx_lock(event);
P
Peter Zijlstra 已提交
4002
	WARN_ON_ONCE(ctx->parent_ctx);
P
Peter Zijlstra 已提交
4003
	perf_remove_from_context(event, DETACH_GROUP);
P
Peter Zijlstra 已提交
4004

P
Peter Zijlstra 已提交
4005
	raw_spin_lock_irq(&ctx->lock);
P
Peter Zijlstra 已提交
4006
	/*
P
Peter Zijlstra 已提交
4007 4008
	 * Mark this even as STATE_DEAD, there is no external reference to it
	 * anymore.
P
Peter Zijlstra 已提交
4009
	 *
P
Peter Zijlstra 已提交
4010 4011 4012
	 * 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
4013
	 *
4014 4015
	 * Thus this guarantees that we will in fact observe and kill _ALL_
	 * child events.
P
Peter Zijlstra 已提交
4016
	 */
P
Peter Zijlstra 已提交
4017 4018 4019 4020
	event->state = PERF_EVENT_STATE_DEAD;
	raw_spin_unlock_irq(&ctx->lock);

	perf_event_ctx_unlock(event, ctx);
P
Peter Zijlstra 已提交
4021

4022 4023 4024
again:
	mutex_lock(&event->child_mutex);
	list_for_each_entry(child, &event->child_list, child_list) {
4025

4026 4027 4028 4029 4030 4031 4032 4033 4034 4035 4036 4037 4038 4039 4040 4041 4042 4043 4044 4045 4046 4047 4048 4049 4050 4051 4052 4053 4054 4055 4056 4057 4058 4059 4060 4061 4062 4063 4064 4065 4066 4067 4068 4069 4070 4071 4072 4073 4074
		/*
		 * 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);

4075 4076
no_ctx:
	put_event(event); /* Must be the 'last' reference */
P
Peter Zijlstra 已提交
4077 4078 4079 4080
	return 0;
}
EXPORT_SYMBOL_GPL(perf_event_release_kernel);

4081 4082 4083
/*
 * Called when the last reference to the file is gone.
 */
4084 4085
static int perf_release(struct inode *inode, struct file *file)
{
4086
	perf_event_release_kernel(file->private_data);
4087
	return 0;
4088 4089
}

4090
u64 perf_event_read_value(struct perf_event *event, u64 *enabled, u64 *running)
4091
{
4092
	struct perf_event *child;
4093 4094
	u64 total = 0;

4095 4096 4097
	*enabled = 0;
	*running = 0;

4098
	mutex_lock(&event->child_mutex);
4099

4100
	(void)perf_event_read(event, false);
4101 4102
	total += perf_event_count(event);

4103 4104 4105 4106 4107 4108
	*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) {
4109
		(void)perf_event_read(child, false);
4110
		total += perf_event_count(child);
4111 4112 4113
		*enabled += child->total_time_enabled;
		*running += child->total_time_running;
	}
4114
	mutex_unlock(&event->child_mutex);
4115 4116 4117

	return total;
}
4118
EXPORT_SYMBOL_GPL(perf_event_read_value);
4119

4120
static int __perf_read_group_add(struct perf_event *leader,
4121
					u64 read_format, u64 *values)
4122
{
4123 4124
	struct perf_event *sub;
	int n = 1; /* skip @nr */
4125
	int ret;
P
Peter Zijlstra 已提交
4126

4127 4128 4129
	ret = perf_event_read(leader, true);
	if (ret)
		return ret;
4130

4131 4132 4133 4134 4135 4136 4137 4138 4139
	/*
	 * 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);
	}
4140

4141 4142 4143 4144 4145 4146 4147 4148 4149
	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);
4150 4151
	if (read_format & PERF_FORMAT_ID)
		values[n++] = primary_event_id(leader);
4152

4153 4154 4155 4156 4157
	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);
	}
4158 4159

	return 0;
4160
}
4161

4162 4163 4164 4165 4166
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;
4167
	int ret;
4168
	u64 *values;
4169

4170
	lockdep_assert_held(&ctx->mutex);
4171

4172 4173 4174
	values = kzalloc(event->read_size, GFP_KERNEL);
	if (!values)
		return -ENOMEM;
4175

4176 4177 4178 4179 4180 4181 4182
	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);
4183

4184 4185 4186 4187 4188 4189 4190 4191 4192
	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;
	}
4193

4194
	mutex_unlock(&leader->child_mutex);
4195

4196
	ret = event->read_size;
4197 4198
	if (copy_to_user(buf, values, event->read_size))
		ret = -EFAULT;
4199
	goto out;
4200

4201 4202 4203
unlock:
	mutex_unlock(&leader->child_mutex);
out:
4204
	kfree(values);
4205
	return ret;
4206 4207
}

4208
static int perf_read_one(struct perf_event *event,
4209 4210
				 u64 read_format, char __user *buf)
{
4211
	u64 enabled, running;
4212 4213 4214
	u64 values[4];
	int n = 0;

4215 4216 4217 4218 4219
	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;
4220
	if (read_format & PERF_FORMAT_ID)
4221
		values[n++] = primary_event_id(event);
4222 4223 4224 4225 4226 4227 4228

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

	return n * sizeof(u64);
}

4229 4230 4231 4232
static bool is_event_hup(struct perf_event *event)
{
	bool no_children;

P
Peter Zijlstra 已提交
4233
	if (event->state > PERF_EVENT_STATE_EXIT)
4234 4235 4236 4237 4238 4239 4240 4241
		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
4242
/*
4243
 * Read the performance event - simple non blocking version for now
T
Thomas Gleixner 已提交
4244 4245
 */
static ssize_t
4246
__perf_read(struct perf_event *event, char __user *buf, size_t count)
T
Thomas Gleixner 已提交
4247
{
4248
	u64 read_format = event->attr.read_format;
4249
	int ret;
T
Thomas Gleixner 已提交
4250

4251
	/*
4252
	 * Return end-of-file for a read on a event that is in
4253 4254 4255
	 * error state (i.e. because it was pinned but it couldn't be
	 * scheduled on to the CPU at some point).
	 */
4256
	if (event->state == PERF_EVENT_STATE_ERROR)
4257 4258
		return 0;

4259
	if (count < event->read_size)
4260 4261
		return -ENOSPC;

4262
	WARN_ON_ONCE(event->ctx->parent_ctx);
4263
	if (read_format & PERF_FORMAT_GROUP)
4264
		ret = perf_read_group(event, read_format, buf);
4265
	else
4266
		ret = perf_read_one(event, read_format, buf);
T
Thomas Gleixner 已提交
4267

4268
	return ret;
T
Thomas Gleixner 已提交
4269 4270 4271 4272 4273
}

static ssize_t
perf_read(struct file *file, char __user *buf, size_t count, loff_t *ppos)
{
4274
	struct perf_event *event = file->private_data;
P
Peter Zijlstra 已提交
4275 4276
	struct perf_event_context *ctx;
	int ret;
T
Thomas Gleixner 已提交
4277

P
Peter Zijlstra 已提交
4278
	ctx = perf_event_ctx_lock(event);
4279
	ret = __perf_read(event, buf, count);
P
Peter Zijlstra 已提交
4280 4281 4282
	perf_event_ctx_unlock(event, ctx);

	return ret;
T
Thomas Gleixner 已提交
4283 4284 4285 4286
}

static unsigned int perf_poll(struct file *file, poll_table *wait)
{
4287
	struct perf_event *event = file->private_data;
4288
	struct ring_buffer *rb;
4289
	unsigned int events = POLLHUP;
P
Peter Zijlstra 已提交
4290

4291
	poll_wait(file, &event->waitq, wait);
4292

4293
	if (is_event_hup(event))
4294
		return events;
P
Peter Zijlstra 已提交
4295

4296
	/*
4297 4298
	 * Pin the event->rb by taking event->mmap_mutex; otherwise
	 * perf_event_set_output() can swizzle our rb and make us miss wakeups.
4299 4300
	 */
	mutex_lock(&event->mmap_mutex);
4301 4302
	rb = event->rb;
	if (rb)
4303
		events = atomic_xchg(&rb->poll, 0);
4304
	mutex_unlock(&event->mmap_mutex);
T
Thomas Gleixner 已提交
4305 4306 4307
	return events;
}

P
Peter Zijlstra 已提交
4308
static void _perf_event_reset(struct perf_event *event)
4309
{
4310
	(void)perf_event_read(event, false);
4311
	local64_set(&event->count, 0);
4312
	perf_event_update_userpage(event);
P
Peter Zijlstra 已提交
4313 4314
}

4315
/*
4316 4317
 * Holding the top-level event's child_mutex means that any
 * descendant process that has inherited this event will block
4318
 * in perf_event_exit_event() if it goes to exit, thus satisfying the
4319
 * task existence requirements of perf_event_enable/disable.
4320
 */
4321 4322
static void perf_event_for_each_child(struct perf_event *event,
					void (*func)(struct perf_event *))
P
Peter Zijlstra 已提交
4323
{
4324
	struct perf_event *child;
P
Peter Zijlstra 已提交
4325

4326
	WARN_ON_ONCE(event->ctx->parent_ctx);
P
Peter Zijlstra 已提交
4327

4328 4329 4330
	mutex_lock(&event->child_mutex);
	func(event);
	list_for_each_entry(child, &event->child_list, child_list)
P
Peter Zijlstra 已提交
4331
		func(child);
4332
	mutex_unlock(&event->child_mutex);
P
Peter Zijlstra 已提交
4333 4334
}

4335 4336
static void perf_event_for_each(struct perf_event *event,
				  void (*func)(struct perf_event *))
P
Peter Zijlstra 已提交
4337
{
4338 4339
	struct perf_event_context *ctx = event->ctx;
	struct perf_event *sibling;
P
Peter Zijlstra 已提交
4340

P
Peter Zijlstra 已提交
4341 4342
	lockdep_assert_held(&ctx->mutex);

4343
	event = event->group_leader;
4344

4345 4346
	perf_event_for_each_child(event, func);
	list_for_each_entry(sibling, &event->sibling_list, group_entry)
4347
		perf_event_for_each_child(sibling, func);
4348 4349
}

4350 4351 4352 4353
static void __perf_event_period(struct perf_event *event,
				struct perf_cpu_context *cpuctx,
				struct perf_event_context *ctx,
				void *info)
4354
{
4355
	u64 value = *((u64 *)info);
4356
	bool active;
4357

4358 4359
	if (event->attr.freq) {
		event->attr.sample_freq = value;
4360
	} else {
4361 4362
		event->attr.sample_period = value;
		event->hw.sample_period = value;
4363
	}
4364 4365 4366 4367

	active = (event->state == PERF_EVENT_STATE_ACTIVE);
	if (active) {
		perf_pmu_disable(ctx->pmu);
4368 4369 4370 4371 4372 4373 4374 4375
		/*
		 * 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);
		}
4376 4377 4378 4379 4380 4381 4382 4383 4384
		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);
	}
4385 4386 4387 4388 4389 4390 4391 4392 4393 4394 4395 4396 4397 4398 4399 4400 4401 4402
}

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;

4403
	event_function_call(event, __perf_event_period, &value);
4404

4405
	return 0;
4406 4407
}

4408 4409
static const struct file_operations perf_fops;

4410
static inline int perf_fget_light(int fd, struct fd *p)
4411
{
4412 4413 4414
	struct fd f = fdget(fd);
	if (!f.file)
		return -EBADF;
4415

4416 4417 4418
	if (f.file->f_op != &perf_fops) {
		fdput(f);
		return -EBADF;
4419
	}
4420 4421
	*p = f;
	return 0;
4422 4423 4424 4425
}

static int perf_event_set_output(struct perf_event *event,
				 struct perf_event *output_event);
L
Li Zefan 已提交
4426
static int perf_event_set_filter(struct perf_event *event, void __user *arg);
4427
static int perf_event_set_bpf_prog(struct perf_event *event, u32 prog_fd);
4428

P
Peter Zijlstra 已提交
4429
static long _perf_ioctl(struct perf_event *event, unsigned int cmd, unsigned long arg)
4430
{
4431
	void (*func)(struct perf_event *);
P
Peter Zijlstra 已提交
4432
	u32 flags = arg;
4433 4434

	switch (cmd) {
4435
	case PERF_EVENT_IOC_ENABLE:
P
Peter Zijlstra 已提交
4436
		func = _perf_event_enable;
4437
		break;
4438
	case PERF_EVENT_IOC_DISABLE:
P
Peter Zijlstra 已提交
4439
		func = _perf_event_disable;
4440
		break;
4441
	case PERF_EVENT_IOC_RESET:
P
Peter Zijlstra 已提交
4442
		func = _perf_event_reset;
4443
		break;
P
Peter Zijlstra 已提交
4444

4445
	case PERF_EVENT_IOC_REFRESH:
P
Peter Zijlstra 已提交
4446
		return _perf_event_refresh(event, arg);
4447

4448 4449
	case PERF_EVENT_IOC_PERIOD:
		return perf_event_period(event, (u64 __user *)arg);
4450

4451 4452 4453 4454 4455 4456 4457 4458 4459
	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;
	}

4460
	case PERF_EVENT_IOC_SET_OUTPUT:
4461 4462 4463
	{
		int ret;
		if (arg != -1) {
4464 4465 4466 4467 4468 4469 4470 4471 4472 4473
			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);
4474 4475 4476
		}
		return ret;
	}
4477

L
Li Zefan 已提交
4478 4479 4480
	case PERF_EVENT_IOC_SET_FILTER:
		return perf_event_set_filter(event, (void __user *)arg);

4481 4482 4483
	case PERF_EVENT_IOC_SET_BPF:
		return perf_event_set_bpf_prog(event, arg);

4484 4485 4486 4487 4488 4489 4490 4491 4492 4493 4494 4495 4496
	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;
	}
4497
	default:
P
Peter Zijlstra 已提交
4498
		return -ENOTTY;
4499
	}
P
Peter Zijlstra 已提交
4500 4501

	if (flags & PERF_IOC_FLAG_GROUP)
4502
		perf_event_for_each(event, func);
P
Peter Zijlstra 已提交
4503
	else
4504
		perf_event_for_each_child(event, func);
P
Peter Zijlstra 已提交
4505 4506

	return 0;
4507 4508
}

P
Peter Zijlstra 已提交
4509 4510 4511 4512 4513 4514 4515 4516 4517 4518 4519 4520 4521
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
4522 4523 4524 4525 4526 4527 4528 4529 4530 4531 4532 4533 4534 4535 4536 4537 4538 4539 4540 4541
#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

4542
int perf_event_task_enable(void)
4543
{
P
Peter Zijlstra 已提交
4544
	struct perf_event_context *ctx;
4545
	struct perf_event *event;
4546

4547
	mutex_lock(&current->perf_event_mutex);
P
Peter Zijlstra 已提交
4548 4549 4550 4551 4552
	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);
	}
4553
	mutex_unlock(&current->perf_event_mutex);
4554 4555 4556 4557

	return 0;
}

4558
int perf_event_task_disable(void)
4559
{
P
Peter Zijlstra 已提交
4560
	struct perf_event_context *ctx;
4561
	struct perf_event *event;
4562

4563
	mutex_lock(&current->perf_event_mutex);
P
Peter Zijlstra 已提交
4564 4565 4566 4567 4568
	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);
	}
4569
	mutex_unlock(&current->perf_event_mutex);
4570 4571 4572 4573

	return 0;
}

4574
static int perf_event_index(struct perf_event *event)
4575
{
P
Peter Zijlstra 已提交
4576 4577 4578
	if (event->hw.state & PERF_HES_STOPPED)
		return 0;

4579
	if (event->state != PERF_EVENT_STATE_ACTIVE)
4580 4581
		return 0;

4582
	return event->pmu->event_idx(event);
4583 4584
}

4585
static void calc_timer_values(struct perf_event *event,
4586
				u64 *now,
4587 4588
				u64 *enabled,
				u64 *running)
4589
{
4590
	u64 ctx_time;
4591

4592 4593
	*now = perf_clock();
	ctx_time = event->shadow_ctx_time + *now;
4594 4595 4596 4597
	*enabled = ctx_time - event->tstamp_enabled;
	*running = ctx_time - event->tstamp_running;
}

4598 4599 4600 4601 4602 4603 4604 4605 4606 4607 4608 4609 4610 4611 4612
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);
4613 4614
	userpg->data_offset = PAGE_SIZE;
	userpg->data_size = perf_data_size(rb);
4615 4616 4617 4618 4619

unlock:
	rcu_read_unlock();
}

4620 4621
void __weak arch_perf_update_userpage(
	struct perf_event *event, struct perf_event_mmap_page *userpg, u64 now)
4622 4623 4624
{
}

4625 4626 4627 4628 4629
/*
 * 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.
 */
4630
void perf_event_update_userpage(struct perf_event *event)
4631
{
4632
	struct perf_event_mmap_page *userpg;
4633
	struct ring_buffer *rb;
4634
	u64 enabled, running, now;
4635 4636

	rcu_read_lock();
4637 4638 4639 4640
	rb = rcu_dereference(event->rb);
	if (!rb)
		goto unlock;

4641 4642 4643 4644 4645 4646 4647 4648 4649
	/*
	 * 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
	 */
4650
	calc_timer_values(event, &now, &enabled, &running);
4651

4652
	userpg = rb->user_page;
4653 4654 4655 4656 4657
	/*
	 * Disable preemption so as to not let the corresponding user-space
	 * spin too long if we get preempted.
	 */
	preempt_disable();
4658
	++userpg->lock;
4659
	barrier();
4660
	userpg->index = perf_event_index(event);
P
Peter Zijlstra 已提交
4661
	userpg->offset = perf_event_count(event);
4662
	if (userpg->index)
4663
		userpg->offset -= local64_read(&event->hw.prev_count);
4664

4665
	userpg->time_enabled = enabled +
4666
			atomic64_read(&event->child_total_time_enabled);
4667

4668
	userpg->time_running = running +
4669
			atomic64_read(&event->child_total_time_running);
4670

4671
	arch_perf_update_userpage(event, userpg, now);
4672

4673
	barrier();
4674
	++userpg->lock;
4675
	preempt_enable();
4676
unlock:
4677
	rcu_read_unlock();
4678 4679
}

4680 4681 4682
static int perf_mmap_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
{
	struct perf_event *event = vma->vm_file->private_data;
4683
	struct ring_buffer *rb;
4684 4685 4686 4687 4688 4689 4690 4691 4692
	int ret = VM_FAULT_SIGBUS;

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

	rcu_read_lock();
4693 4694
	rb = rcu_dereference(event->rb);
	if (!rb)
4695 4696 4697 4698 4699
		goto unlock;

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

4700
	vmf->page = perf_mmap_to_page(rb, vmf->pgoff);
4701 4702 4703 4704 4705 4706 4707 4708 4709 4710 4711 4712 4713 4714
	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;
}

4715 4716 4717
static void ring_buffer_attach(struct perf_event *event,
			       struct ring_buffer *rb)
{
4718
	struct ring_buffer *old_rb = NULL;
4719 4720
	unsigned long flags;

4721 4722 4723 4724 4725 4726
	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);
4727

4728 4729 4730 4731
		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);
4732

4733 4734
		event->rcu_batches = get_state_synchronize_rcu();
		event->rcu_pending = 1;
4735
	}
4736

4737
	if (rb) {
4738 4739 4740 4741 4742
		if (event->rcu_pending) {
			cond_synchronize_rcu(event->rcu_batches);
			event->rcu_pending = 0;
		}

4743 4744 4745 4746 4747 4748 4749 4750 4751 4752 4753 4754 4755 4756 4757 4758
		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);
	}
4759 4760 4761 4762 4763 4764 4765 4766
}

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

	rcu_read_lock();
	rb = rcu_dereference(event->rb);
4767 4768 4769 4770
	if (rb) {
		list_for_each_entry_rcu(event, &rb->event_list, rb_entry)
			wake_up_all(&event->waitq);
	}
4771 4772 4773
	rcu_read_unlock();
}

4774
struct ring_buffer *ring_buffer_get(struct perf_event *event)
4775
{
4776
	struct ring_buffer *rb;
4777

4778
	rcu_read_lock();
4779 4780 4781 4782
	rb = rcu_dereference(event->rb);
	if (rb) {
		if (!atomic_inc_not_zero(&rb->refcount))
			rb = NULL;
4783 4784 4785
	}
	rcu_read_unlock();

4786
	return rb;
4787 4788
}

4789
void ring_buffer_put(struct ring_buffer *rb)
4790
{
4791
	if (!atomic_dec_and_test(&rb->refcount))
4792
		return;
4793

4794
	WARN_ON_ONCE(!list_empty(&rb->event_list));
4795

4796
	call_rcu(&rb->rcu_head, rb_free_rcu);
4797 4798 4799 4800
}

static void perf_mmap_open(struct vm_area_struct *vma)
{
4801
	struct perf_event *event = vma->vm_file->private_data;
4802

4803
	atomic_inc(&event->mmap_count);
4804
	atomic_inc(&event->rb->mmap_count);
4805

4806 4807 4808
	if (vma->vm_pgoff)
		atomic_inc(&event->rb->aux_mmap_count);

4809 4810
	if (event->pmu->event_mapped)
		event->pmu->event_mapped(event);
4811 4812
}

4813 4814
static void perf_pmu_output_stop(struct perf_event *event);

4815 4816 4817 4818 4819 4820 4821 4822
/*
 * 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.
 */
4823 4824
static void perf_mmap_close(struct vm_area_struct *vma)
{
4825
	struct perf_event *event = vma->vm_file->private_data;
4826

4827
	struct ring_buffer *rb = ring_buffer_get(event);
4828 4829 4830
	struct user_struct *mmap_user = rb->mmap_user;
	int mmap_locked = rb->mmap_locked;
	unsigned long size = perf_data_size(rb);
4831

4832 4833 4834
	if (event->pmu->event_unmapped)
		event->pmu->event_unmapped(event);

4835 4836 4837 4838 4839 4840 4841
	/*
	 * 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)) {
4842 4843 4844 4845 4846 4847 4848 4849 4850
		/*
		 * 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 */
4851 4852 4853
		atomic_long_sub(rb->aux_nr_pages, &mmap_user->locked_vm);
		vma->vm_mm->pinned_vm -= rb->aux_mmap_locked;

4854
		/* this has to be the last one */
4855
		rb_free_aux(rb);
4856 4857
		WARN_ON_ONCE(atomic_read(&rb->aux_refcount));

4858 4859 4860
		mutex_unlock(&event->mmap_mutex);
	}

4861 4862 4863
	atomic_dec(&rb->mmap_count);

	if (!atomic_dec_and_mutex_lock(&event->mmap_count, &event->mmap_mutex))
4864
		goto out_put;
4865

4866
	ring_buffer_attach(event, NULL);
4867 4868 4869
	mutex_unlock(&event->mmap_mutex);

	/* If there's still other mmap()s of this buffer, we're done. */
4870 4871
	if (atomic_read(&rb->mmap_count))
		goto out_put;
4872

4873 4874 4875 4876 4877 4878 4879 4880 4881 4882 4883 4884 4885 4886 4887 4888
	/*
	 * 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();
4889

4890 4891 4892 4893 4894 4895 4896 4897 4898 4899 4900
		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.
		 */
4901 4902 4903
		if (event->rb == rb)
			ring_buffer_attach(event, NULL);

4904
		mutex_unlock(&event->mmap_mutex);
4905
		put_event(event);
4906

4907 4908 4909 4910 4911
		/*
		 * Restart the iteration; either we're on the wrong list or
		 * destroyed its integrity by doing a deletion.
		 */
		goto again;
4912
	}
4913 4914 4915 4916 4917 4918 4919 4920 4921 4922 4923 4924 4925 4926 4927
	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);

4928
out_put:
4929
	ring_buffer_put(rb); /* could be last */
4930 4931
}

4932
static const struct vm_operations_struct perf_mmap_vmops = {
4933
	.open		= perf_mmap_open,
4934
	.close		= perf_mmap_close, /* non mergable */
4935 4936
	.fault		= perf_mmap_fault,
	.page_mkwrite	= perf_mmap_fault,
4937 4938 4939 4940
};

static int perf_mmap(struct file *file, struct vm_area_struct *vma)
{
4941
	struct perf_event *event = file->private_data;
4942
	unsigned long user_locked, user_lock_limit;
4943
	struct user_struct *user = current_user();
4944
	unsigned long locked, lock_limit;
4945
	struct ring_buffer *rb = NULL;
4946 4947
	unsigned long vma_size;
	unsigned long nr_pages;
4948
	long user_extra = 0, extra = 0;
4949
	int ret = 0, flags = 0;
4950

4951 4952 4953
	/*
	 * Don't allow mmap() of inherited per-task counters. This would
	 * create a performance issue due to all children writing to the
4954
	 * same rb.
4955 4956 4957 4958
	 */
	if (event->cpu == -1 && event->attr.inherit)
		return -EINVAL;

4959
	if (!(vma->vm_flags & VM_SHARED))
4960
		return -EINVAL;
4961 4962

	vma_size = vma->vm_end - vma->vm_start;
4963 4964 4965 4966 4967 4968 4969 4970 4971 4972 4973 4974 4975 4976 4977 4978 4979 4980 4981 4982 4983 4984 4985 4986 4987 4988 4989 4990 4991 4992 4993 4994 4995 4996 4997 4998 4999 5000 5001 5002 5003 5004 5005 5006 5007 5008 5009 5010 5011 5012 5013 5014 5015 5016 5017 5018 5019 5020 5021 5022

	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;
	}
5023

5024
	/*
5025
	 * If we have rb pages ensure they're a power-of-two number, so we
5026 5027
	 * can do bitmasks instead of modulo.
	 */
5028
	if (nr_pages != 0 && !is_power_of_2(nr_pages))
5029 5030
		return -EINVAL;

5031
	if (vma_size != PAGE_SIZE * (1 + nr_pages))
5032 5033
		return -EINVAL;

5034
	WARN_ON_ONCE(event->ctx->parent_ctx);
5035
again:
5036
	mutex_lock(&event->mmap_mutex);
5037
	if (event->rb) {
5038
		if (event->rb->nr_pages != nr_pages) {
5039
			ret = -EINVAL;
5040 5041 5042 5043 5044 5045 5046 5047 5048 5049 5050 5051 5052
			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;
		}

5053 5054 5055
		goto unlock;
	}

5056
	user_extra = nr_pages + 1;
5057 5058

accounting:
5059
	user_lock_limit = sysctl_perf_event_mlock >> (PAGE_SHIFT - 10);
I
Ingo Molnar 已提交
5060 5061 5062 5063 5064 5065

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

5066
	user_locked = atomic_long_read(&user->locked_vm) + user_extra;
5067

5068 5069
	if (user_locked > user_lock_limit)
		extra = user_locked - user_lock_limit;
5070

5071
	lock_limit = rlimit(RLIMIT_MEMLOCK);
5072
	lock_limit >>= PAGE_SHIFT;
5073
	locked = vma->vm_mm->pinned_vm + extra;
5074

5075 5076
	if ((locked > lock_limit) && perf_paranoid_tracepoint_raw() &&
		!capable(CAP_IPC_LOCK)) {
5077 5078 5079
		ret = -EPERM;
		goto unlock;
	}
5080

5081
	WARN_ON(!rb && event->rb);
5082

5083
	if (vma->vm_flags & VM_WRITE)
5084
		flags |= RING_BUFFER_WRITABLE;
5085

5086
	if (!rb) {
5087 5088 5089
		rb = rb_alloc(nr_pages,
			      event->attr.watermark ? event->attr.wakeup_watermark : 0,
			      event->cpu, flags);
P
Peter Zijlstra 已提交
5090

5091 5092 5093 5094
		if (!rb) {
			ret = -ENOMEM;
			goto unlock;
		}
5095

5096 5097 5098
		atomic_set(&rb->mmap_count, 1);
		rb->mmap_user = get_current_user();
		rb->mmap_locked = extra;
P
Peter Zijlstra 已提交
5099

5100
		ring_buffer_attach(event, rb);
5101

5102 5103 5104
		perf_event_init_userpage(event);
		perf_event_update_userpage(event);
	} else {
5105 5106
		ret = rb_alloc_aux(rb, event, vma->vm_pgoff, nr_pages,
				   event->attr.aux_watermark, flags);
5107 5108 5109
		if (!ret)
			rb->aux_mmap_locked = extra;
	}
5110

5111
unlock:
5112 5113 5114 5115
	if (!ret) {
		atomic_long_add(user_extra, &user->locked_vm);
		vma->vm_mm->pinned_vm += extra;

5116
		atomic_inc(&event->mmap_count);
5117 5118 5119 5120
	} else if (rb) {
		atomic_dec(&rb->mmap_count);
	}
aux_unlock:
5121
	mutex_unlock(&event->mmap_mutex);
5122

5123 5124 5125 5126
	/*
	 * Since pinned accounting is per vm we cannot allow fork() to copy our
	 * vma.
	 */
P
Peter Zijlstra 已提交
5127
	vma->vm_flags |= VM_DONTCOPY | VM_DONTEXPAND | VM_DONTDUMP;
5128
	vma->vm_ops = &perf_mmap_vmops;
5129

5130 5131 5132
	if (event->pmu->event_mapped)
		event->pmu->event_mapped(event);

5133
	return ret;
5134 5135
}

P
Peter Zijlstra 已提交
5136 5137
static int perf_fasync(int fd, struct file *filp, int on)
{
A
Al Viro 已提交
5138
	struct inode *inode = file_inode(filp);
5139
	struct perf_event *event = filp->private_data;
P
Peter Zijlstra 已提交
5140 5141
	int retval;

A
Al Viro 已提交
5142
	inode_lock(inode);
5143
	retval = fasync_helper(fd, filp, on, &event->fasync);
A
Al Viro 已提交
5144
	inode_unlock(inode);
P
Peter Zijlstra 已提交
5145 5146 5147 5148 5149 5150 5151

	if (retval < 0)
		return retval;

	return 0;
}

T
Thomas Gleixner 已提交
5152
static const struct file_operations perf_fops = {
5153
	.llseek			= no_llseek,
T
Thomas Gleixner 已提交
5154 5155 5156
	.release		= perf_release,
	.read			= perf_read,
	.poll			= perf_poll,
5157
	.unlocked_ioctl		= perf_ioctl,
P
Pawel Moll 已提交
5158
	.compat_ioctl		= perf_compat_ioctl,
5159
	.mmap			= perf_mmap,
P
Peter Zijlstra 已提交
5160
	.fasync			= perf_fasync,
T
Thomas Gleixner 已提交
5161 5162
};

5163
/*
5164
 * Perf event wakeup
5165 5166 5167 5168 5169
 *
 * If there's data, ensure we set the poll() state and publish everything
 * to user-space before waking everybody up.
 */

5170 5171 5172 5173 5174 5175 5176 5177
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;
}

5178
void perf_event_wakeup(struct perf_event *event)
5179
{
5180
	ring_buffer_wakeup(event);
5181

5182
	if (event->pending_kill) {
5183
		kill_fasync(perf_event_fasync(event), SIGIO, event->pending_kill);
5184
		event->pending_kill = 0;
5185
	}
5186 5187
}

5188
static void perf_pending_event(struct irq_work *entry)
5189
{
5190 5191
	struct perf_event *event = container_of(entry,
			struct perf_event, pending);
5192 5193 5194 5195 5196 5197 5198
	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'.
	 */
5199

5200 5201
	if (event->pending_disable) {
		event->pending_disable = 0;
5202
		perf_event_disable_local(event);
5203 5204
	}

5205 5206 5207
	if (event->pending_wakeup) {
		event->pending_wakeup = 0;
		perf_event_wakeup(event);
5208
	}
5209 5210 5211

	if (rctx >= 0)
		perf_swevent_put_recursion_context(rctx);
5212 5213
}

5214 5215 5216 5217 5218 5219 5220 5221 5222 5223 5224 5225 5226 5227 5228 5229 5230 5231 5232 5233 5234
/*
 * 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);

5235 5236 5237 5238 5239 5240 5241 5242 5243 5244 5245 5246 5247 5248 5249
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);
	}
}

5250
static void perf_sample_regs_user(struct perf_regs *regs_user,
5251 5252
				  struct pt_regs *regs,
				  struct pt_regs *regs_user_copy)
5253
{
5254 5255
	if (user_mode(regs)) {
		regs_user->abi = perf_reg_abi(current);
5256
		regs_user->regs = regs;
5257 5258
	} else if (current->mm) {
		perf_get_regs_user(regs_user, regs, regs_user_copy);
5259 5260 5261
	} else {
		regs_user->abi = PERF_SAMPLE_REGS_ABI_NONE;
		regs_user->regs = NULL;
5262 5263 5264
	}
}

5265 5266 5267 5268 5269 5270 5271 5272
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);
}


5273 5274 5275 5276 5277 5278 5279 5280 5281 5282 5283 5284 5285 5286 5287 5288 5289 5290 5291 5292 5293 5294 5295 5296 5297 5298 5299 5300 5301 5302 5303 5304 5305 5306 5307 5308 5309 5310 5311 5312 5313 5314 5315 5316 5317 5318 5319 5320 5321 5322 5323 5324 5325 5326 5327 5328 5329 5330 5331 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
/*
 * 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);
	}
}

5368 5369 5370
static void __perf_event_header__init_id(struct perf_event_header *header,
					 struct perf_sample_data *data,
					 struct perf_event *event)
5371 5372 5373 5374 5375 5376 5377 5378 5379 5380 5381 5382 5383
{
	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)
5384
		data->time = perf_event_clock(event);
5385

5386
	if (sample_type & (PERF_SAMPLE_ID | PERF_SAMPLE_IDENTIFIER))
5387 5388 5389 5390 5391 5392 5393 5394 5395 5396 5397
		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;
	}
}

5398 5399 5400
void perf_event_header__init_id(struct perf_event_header *header,
				struct perf_sample_data *data,
				struct perf_event *event)
5401 5402 5403 5404 5405 5406 5407 5408 5409 5410 5411 5412 5413 5414 5415 5416 5417 5418 5419 5420 5421 5422 5423 5424
{
	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);
5425 5426 5427

	if (sample_type & PERF_SAMPLE_IDENTIFIER)
		perf_output_put(handle, data->id);
5428 5429
}

5430 5431 5432
void perf_event__output_id_sample(struct perf_event *event,
				  struct perf_output_handle *handle,
				  struct perf_sample_data *sample)
5433 5434 5435 5436 5437
{
	if (event->attr.sample_id_all)
		__perf_event__output_id_sample(handle, sample);
}

5438
static void perf_output_read_one(struct perf_output_handle *handle,
5439 5440
				 struct perf_event *event,
				 u64 enabled, u64 running)
5441
{
5442
	u64 read_format = event->attr.read_format;
5443 5444 5445
	u64 values[4];
	int n = 0;

P
Peter Zijlstra 已提交
5446
	values[n++] = perf_event_count(event);
5447
	if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED) {
5448
		values[n++] = enabled +
5449
			atomic64_read(&event->child_total_time_enabled);
5450 5451
	}
	if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING) {
5452
		values[n++] = running +
5453
			atomic64_read(&event->child_total_time_running);
5454 5455
	}
	if (read_format & PERF_FORMAT_ID)
5456
		values[n++] = primary_event_id(event);
5457

5458
	__output_copy(handle, values, n * sizeof(u64));
5459 5460 5461
}

/*
5462
 * XXX PERF_FORMAT_GROUP vs inherited events seems difficult.
5463 5464
 */
static void perf_output_read_group(struct perf_output_handle *handle,
5465 5466
			    struct perf_event *event,
			    u64 enabled, u64 running)
5467
{
5468 5469
	struct perf_event *leader = event->group_leader, *sub;
	u64 read_format = event->attr.read_format;
5470 5471 5472 5473 5474 5475
	u64 values[5];
	int n = 0;

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

	if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED)
5476
		values[n++] = enabled;
5477 5478

	if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING)
5479
		values[n++] = running;
5480

5481
	if (leader != event)
5482 5483
		leader->pmu->read(leader);

P
Peter Zijlstra 已提交
5484
	values[n++] = perf_event_count(leader);
5485
	if (read_format & PERF_FORMAT_ID)
5486
		values[n++] = primary_event_id(leader);
5487

5488
	__output_copy(handle, values, n * sizeof(u64));
5489

5490
	list_for_each_entry(sub, &leader->sibling_list, group_entry) {
5491 5492
		n = 0;

5493 5494
		if ((sub != event) &&
		    (sub->state == PERF_EVENT_STATE_ACTIVE))
5495 5496
			sub->pmu->read(sub);

P
Peter Zijlstra 已提交
5497
		values[n++] = perf_event_count(sub);
5498
		if (read_format & PERF_FORMAT_ID)
5499
			values[n++] = primary_event_id(sub);
5500

5501
		__output_copy(handle, values, n * sizeof(u64));
5502 5503 5504
	}
}

5505 5506 5507
#define PERF_FORMAT_TOTAL_TIMES (PERF_FORMAT_TOTAL_TIME_ENABLED|\
				 PERF_FORMAT_TOTAL_TIME_RUNNING)

5508
static void perf_output_read(struct perf_output_handle *handle,
5509
			     struct perf_event *event)
5510
{
5511
	u64 enabled = 0, running = 0, now;
5512 5513 5514 5515 5516 5517 5518 5519 5520 5521 5522
	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
	 */
5523
	if (read_format & PERF_FORMAT_TOTAL_TIMES)
5524
		calc_timer_values(event, &now, &enabled, &running);
5525

5526
	if (event->attr.read_format & PERF_FORMAT_GROUP)
5527
		perf_output_read_group(handle, event, enabled, running);
5528
	else
5529
		perf_output_read_one(handle, event, enabled, running);
5530 5531
}

5532 5533 5534
void perf_output_sample(struct perf_output_handle *handle,
			struct perf_event_header *header,
			struct perf_sample_data *data,
5535
			struct perf_event *event)
5536 5537 5538 5539 5540
{
	u64 sample_type = data->type;

	perf_output_put(handle, *header);

5541 5542 5543
	if (sample_type & PERF_SAMPLE_IDENTIFIER)
		perf_output_put(handle, data->id);

5544 5545 5546 5547 5548 5549 5550 5551 5552 5553 5554 5555 5556 5557 5558 5559 5560 5561 5562 5563 5564 5565 5566 5567 5568
	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)
5569
		perf_output_read(handle, event);
5570 5571 5572 5573 5574 5575 5576 5577 5578 5579

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

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

			size *= sizeof(u64);

5580
			__output_copy(handle, data->callchain, size);
5581 5582 5583 5584 5585 5586 5587 5588
		} else {
			u64 nr = 0;
			perf_output_put(handle, nr);
		}
	}

	if (sample_type & PERF_SAMPLE_RAW) {
		if (data->raw) {
5589 5590 5591 5592 5593 5594 5595 5596 5597
			u32 raw_size = data->raw->size;
			u32 real_size = round_up(raw_size + sizeof(u32),
						 sizeof(u64)) - sizeof(u32);
			u64 zero = 0;

			perf_output_put(handle, real_size);
			__output_copy(handle, data->raw->data, raw_size);
			if (real_size - raw_size)
				__output_copy(handle, &zero, real_size - raw_size);
5598 5599 5600 5601 5602 5603 5604 5605 5606 5607 5608
		} else {
			struct {
				u32	size;
				u32	data;
			} raw = {
				.size = sizeof(u32),
				.data = 0,
			};
			perf_output_put(handle, raw);
		}
	}
5609

5610 5611 5612 5613 5614 5615 5616 5617 5618 5619 5620 5621 5622 5623 5624 5625 5626
	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);
		}
	}
5627 5628 5629 5630 5631 5632 5633 5634 5635 5636 5637 5638 5639 5640 5641 5642 5643

	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);
		}
	}
5644

5645
	if (sample_type & PERF_SAMPLE_STACK_USER) {
5646 5647 5648
		perf_output_sample_ustack(handle,
					  data->stack_user_size,
					  data->regs_user.regs);
5649
	}
A
Andi Kleen 已提交
5650 5651 5652

	if (sample_type & PERF_SAMPLE_WEIGHT)
		perf_output_put(handle, data->weight);
5653 5654 5655

	if (sample_type & PERF_SAMPLE_DATA_SRC)
		perf_output_put(handle, data->data_src.val);
5656

A
Andi Kleen 已提交
5657 5658 5659
	if (sample_type & PERF_SAMPLE_TRANSACTION)
		perf_output_put(handle, data->txn);

5660 5661 5662 5663 5664 5665 5666 5667 5668 5669 5670 5671 5672 5673 5674 5675 5676
	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);
		}
	}

5677 5678 5679 5680 5681 5682 5683 5684 5685 5686 5687 5688 5689
	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);
			}
		}
	}
5690 5691 5692 5693
}

void perf_prepare_sample(struct perf_event_header *header,
			 struct perf_sample_data *data,
5694
			 struct perf_event *event,
5695
			 struct pt_regs *regs)
5696
{
5697
	u64 sample_type = event->attr.sample_type;
5698

5699
	header->type = PERF_RECORD_SAMPLE;
5700
	header->size = sizeof(*header) + event->header_size;
5701 5702 5703

	header->misc = 0;
	header->misc |= perf_misc_flags(regs);
5704

5705
	__perf_event_header__init_id(header, data, event);
5706

5707
	if (sample_type & PERF_SAMPLE_IP)
5708 5709
		data->ip = perf_instruction_pointer(regs);

5710
	if (sample_type & PERF_SAMPLE_CALLCHAIN) {
5711
		int size = 1;
5712

5713
		data->callchain = perf_callchain(event, regs);
5714 5715 5716 5717 5718

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

		header->size += size * sizeof(u64);
5719 5720
	}

5721
	if (sample_type & PERF_SAMPLE_RAW) {
5722 5723 5724 5725 5726 5727 5728
		int size = sizeof(u32);

		if (data->raw)
			size += data->raw->size;
		else
			size += sizeof(u32);

5729
		header->size += round_up(size, sizeof(u64));
5730
	}
5731 5732 5733 5734 5735 5736 5737 5738 5739

	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;
	}
5740

5741
	if (sample_type & (PERF_SAMPLE_REGS_USER | PERF_SAMPLE_STACK_USER))
5742 5743
		perf_sample_regs_user(&data->regs_user, regs,
				      &data->regs_user_copy);
5744

5745 5746 5747 5748 5749 5750 5751 5752 5753 5754 5755
	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;
	}
5756 5757 5758 5759 5760 5761 5762 5763 5764 5765 5766 5767

	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,
5768
						     data->regs_user.regs);
5769 5770 5771 5772 5773 5774 5775 5776 5777 5778 5779 5780

		/*
		 * 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;
	}
5781 5782 5783 5784 5785 5786 5787 5788 5789 5790 5791 5792 5793 5794 5795

	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;
	}
5796
}
5797

5798 5799 5800 5801 5802 5803 5804
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))
5805 5806 5807
{
	struct perf_output_handle handle;
	struct perf_event_header header;
5808

5809 5810 5811
	/* protect the callchain buffers */
	rcu_read_lock();

5812
	perf_prepare_sample(&header, data, event, regs);
P
Peter Zijlstra 已提交
5813

5814
	if (output_begin(&handle, event, header.size))
5815
		goto exit;
5816

5817
	perf_output_sample(&handle, &header, data, event);
5818

5819
	perf_output_end(&handle);
5820 5821 5822

exit:
	rcu_read_unlock();
5823 5824
}

5825 5826 5827 5828 5829 5830 5831 5832 5833 5834 5835 5836 5837 5838 5839 5840 5841 5842 5843 5844 5845 5846 5847 5848
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);
}

5849
/*
5850
 * read event_id
5851 5852 5853 5854 5855 5856 5857 5858 5859 5860
 */

struct perf_read_event {
	struct perf_event_header	header;

	u32				pid;
	u32				tid;
};

static void
5861
perf_event_read_event(struct perf_event *event,
5862 5863 5864
			struct task_struct *task)
{
	struct perf_output_handle handle;
5865
	struct perf_sample_data sample;
5866
	struct perf_read_event read_event = {
5867
		.header = {
5868
			.type = PERF_RECORD_READ,
5869
			.misc = 0,
5870
			.size = sizeof(read_event) + event->read_size,
5871
		},
5872 5873
		.pid = perf_event_pid(event, task),
		.tid = perf_event_tid(event, task),
5874
	};
5875
	int ret;
5876

5877
	perf_event_header__init_id(&read_event.header, &sample, event);
5878
	ret = perf_output_begin(&handle, event, read_event.header.size);
5879 5880 5881
	if (ret)
		return;

5882
	perf_output_put(&handle, read_event);
5883
	perf_output_read(&handle, event);
5884
	perf_event__output_id_sample(event, &handle, &sample);
5885

5886 5887 5888
	perf_output_end(&handle);
}

5889
typedef void (perf_iterate_f)(struct perf_event *event, void *data);
5890 5891

static void
5892 5893
perf_iterate_ctx(struct perf_event_context *ctx,
		   perf_iterate_f output,
5894
		   void *data, bool all)
5895 5896 5897 5898
{
	struct perf_event *event;

	list_for_each_entry_rcu(event, &ctx->event_list, event_entry) {
5899 5900 5901 5902 5903 5904 5905
		if (!all) {
			if (event->state < PERF_EVENT_STATE_INACTIVE)
				continue;
			if (!event_filter_match(event))
				continue;
		}

5906
		output(event, data);
5907 5908 5909
	}
}

5910
static void perf_iterate_sb_cpu(perf_iterate_f output, void *data)
5911 5912 5913 5914 5915 5916 5917 5918 5919 5920 5921 5922 5923
{
	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) {
		if (event->state < PERF_EVENT_STATE_INACTIVE)
			continue;
		if (!event_filter_match(event))
			continue;
		output(event, data);
	}
}

5924 5925 5926 5927 5928 5929
/*
 * 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.
 */
5930
static void
5931
perf_iterate_sb(perf_iterate_f output, void *data,
5932 5933 5934 5935 5936
	       struct perf_event_context *task_ctx)
{
	struct perf_event_context *ctx;
	int ctxn;

5937 5938 5939
	rcu_read_lock();
	preempt_disable();

J
Jiri Olsa 已提交
5940
	/*
5941 5942
	 * 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
5943 5944 5945
	 * context.
	 */
	if (task_ctx) {
5946 5947
		perf_iterate_ctx(task_ctx, output, data, false);
		goto done;
J
Jiri Olsa 已提交
5948 5949
	}

5950
	perf_iterate_sb_cpu(output, data);
5951 5952

	for_each_task_context_nr(ctxn) {
5953 5954
		ctx = rcu_dereference(current->perf_event_ctxp[ctxn]);
		if (ctx)
5955
			perf_iterate_ctx(ctx, output, data, false);
5956
	}
5957
done:
5958
	preempt_enable();
5959
	rcu_read_unlock();
5960 5961
}

5962 5963 5964 5965 5966 5967 5968 5969 5970 5971 5972 5973 5974 5975 5976 5977 5978 5979 5980 5981 5982 5983 5984 5985 5986 5987 5988 5989 5990 5991 5992 5993 5994 5995 5996 5997 5998 5999 6000 6001 6002 6003 6004 6005 6006
/*
 * 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);

6007
		perf_iterate_ctx(ctx, perf_event_addr_filters_exec, NULL,
6008 6009 6010 6011 6012
				   true);
	}
	rcu_read_unlock();
}

6013 6014 6015 6016 6017 6018 6019 6020 6021 6022
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;
6023 6024 6025
	struct stop_event_data sd = {
		.event	= event,
	};
6026 6027 6028 6029 6030 6031 6032 6033 6034 6035 6036 6037

	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)
6038
		ro->err = __perf_event_stop(&sd);
6039 6040 6041 6042 6043 6044 6045 6046 6047 6048 6049 6050
}

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();
6051
	perf_iterate_ctx(&cpuctx->ctx, __perf_event_output_stop, &ro, false);
6052
	if (cpuctx->task_ctx)
6053
		perf_iterate_ctx(cpuctx->task_ctx, __perf_event_output_stop,
6054
				   &ro, false);
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
	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();
6088 6089
}

P
Peter Zijlstra 已提交
6090
/*
P
Peter Zijlstra 已提交
6091 6092
 * task tracking -- fork/exit
 *
6093
 * enabled by: attr.comm | attr.mmap | attr.mmap2 | attr.mmap_data | attr.task
P
Peter Zijlstra 已提交
6094 6095
 */

P
Peter Zijlstra 已提交
6096
struct perf_task_event {
6097
	struct task_struct		*task;
6098
	struct perf_event_context	*task_ctx;
P
Peter Zijlstra 已提交
6099 6100 6101 6102 6103 6104

	struct {
		struct perf_event_header	header;

		u32				pid;
		u32				ppid;
P
Peter Zijlstra 已提交
6105 6106
		u32				tid;
		u32				ptid;
6107
		u64				time;
6108
	} event_id;
P
Peter Zijlstra 已提交
6109 6110
};

6111 6112
static int perf_event_task_match(struct perf_event *event)
{
6113 6114 6115
	return event->attr.comm  || event->attr.mmap ||
	       event->attr.mmap2 || event->attr.mmap_data ||
	       event->attr.task;
6116 6117
}

6118
static void perf_event_task_output(struct perf_event *event,
6119
				   void *data)
P
Peter Zijlstra 已提交
6120
{
6121
	struct perf_task_event *task_event = data;
P
Peter Zijlstra 已提交
6122
	struct perf_output_handle handle;
6123
	struct perf_sample_data	sample;
P
Peter Zijlstra 已提交
6124
	struct task_struct *task = task_event->task;
6125
	int ret, size = task_event->event_id.header.size;
6126

6127 6128 6129
	if (!perf_event_task_match(event))
		return;

6130
	perf_event_header__init_id(&task_event->event_id.header, &sample, event);
P
Peter Zijlstra 已提交
6131

6132
	ret = perf_output_begin(&handle, event,
6133
				task_event->event_id.header.size);
6134
	if (ret)
6135
		goto out;
P
Peter Zijlstra 已提交
6136

6137 6138
	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
6139

6140 6141
	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
6142

6143 6144
	task_event->event_id.time = perf_event_clock(event);

6145
	perf_output_put(&handle, task_event->event_id);
6146

6147 6148
	perf_event__output_id_sample(event, &handle, &sample);

P
Peter Zijlstra 已提交
6149
	perf_output_end(&handle);
6150 6151
out:
	task_event->event_id.header.size = size;
P
Peter Zijlstra 已提交
6152 6153
}

6154 6155
static void perf_event_task(struct task_struct *task,
			      struct perf_event_context *task_ctx,
6156
			      int new)
P
Peter Zijlstra 已提交
6157
{
P
Peter Zijlstra 已提交
6158
	struct perf_task_event task_event;
P
Peter Zijlstra 已提交
6159

6160 6161 6162
	if (!atomic_read(&nr_comm_events) &&
	    !atomic_read(&nr_mmap_events) &&
	    !atomic_read(&nr_task_events))
P
Peter Zijlstra 已提交
6163 6164
		return;

P
Peter Zijlstra 已提交
6165
	task_event = (struct perf_task_event){
6166 6167
		.task	  = task,
		.task_ctx = task_ctx,
6168
		.event_id    = {
P
Peter Zijlstra 已提交
6169
			.header = {
6170
				.type = new ? PERF_RECORD_FORK : PERF_RECORD_EXIT,
6171
				.misc = 0,
6172
				.size = sizeof(task_event.event_id),
P
Peter Zijlstra 已提交
6173
			},
6174 6175
			/* .pid  */
			/* .ppid */
P
Peter Zijlstra 已提交
6176 6177
			/* .tid  */
			/* .ptid */
6178
			/* .time */
P
Peter Zijlstra 已提交
6179 6180 6181
		},
	};

6182
	perf_iterate_sb(perf_event_task_output,
6183 6184
		       &task_event,
		       task_ctx);
P
Peter Zijlstra 已提交
6185 6186
}

6187
void perf_event_fork(struct task_struct *task)
P
Peter Zijlstra 已提交
6188
{
6189
	perf_event_task(task, NULL, 1);
P
Peter Zijlstra 已提交
6190 6191
}

6192 6193 6194 6195 6196
/*
 * comm tracking
 */

struct perf_comm_event {
6197 6198
	struct task_struct	*task;
	char			*comm;
6199 6200 6201 6202 6203 6204 6205
	int			comm_size;

	struct {
		struct perf_event_header	header;

		u32				pid;
		u32				tid;
6206
	} event_id;
6207 6208
};

6209 6210 6211 6212 6213
static int perf_event_comm_match(struct perf_event *event)
{
	return event->attr.comm;
}

6214
static void perf_event_comm_output(struct perf_event *event,
6215
				   void *data)
6216
{
6217
	struct perf_comm_event *comm_event = data;
6218
	struct perf_output_handle handle;
6219
	struct perf_sample_data sample;
6220
	int size = comm_event->event_id.header.size;
6221 6222
	int ret;

6223 6224 6225
	if (!perf_event_comm_match(event))
		return;

6226 6227
	perf_event_header__init_id(&comm_event->event_id.header, &sample, event);
	ret = perf_output_begin(&handle, event,
6228
				comm_event->event_id.header.size);
6229 6230

	if (ret)
6231
		goto out;
6232

6233 6234
	comm_event->event_id.pid = perf_event_pid(event, comm_event->task);
	comm_event->event_id.tid = perf_event_tid(event, comm_event->task);
6235

6236
	perf_output_put(&handle, comm_event->event_id);
6237
	__output_copy(&handle, comm_event->comm,
6238
				   comm_event->comm_size);
6239 6240 6241

	perf_event__output_id_sample(event, &handle, &sample);

6242
	perf_output_end(&handle);
6243 6244
out:
	comm_event->event_id.header.size = size;
6245 6246
}

6247
static void perf_event_comm_event(struct perf_comm_event *comm_event)
6248
{
6249
	char comm[TASK_COMM_LEN];
6250 6251
	unsigned int size;

6252
	memset(comm, 0, sizeof(comm));
6253
	strlcpy(comm, comm_event->task->comm, sizeof(comm));
6254
	size = ALIGN(strlen(comm)+1, sizeof(u64));
6255 6256 6257 6258

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

6259
	comm_event->event_id.header.size = sizeof(comm_event->event_id) + size;
P
Peter Zijlstra 已提交
6260

6261
	perf_iterate_sb(perf_event_comm_output,
6262 6263
		       comm_event,
		       NULL);
6264 6265
}

6266
void perf_event_comm(struct task_struct *task, bool exec)
6267
{
6268 6269
	struct perf_comm_event comm_event;

6270
	if (!atomic_read(&nr_comm_events))
6271
		return;
6272

6273
	comm_event = (struct perf_comm_event){
6274
		.task	= task,
6275 6276
		/* .comm      */
		/* .comm_size */
6277
		.event_id  = {
6278
			.header = {
6279
				.type = PERF_RECORD_COMM,
6280
				.misc = exec ? PERF_RECORD_MISC_COMM_EXEC : 0,
6281 6282 6283 6284
				/* .size */
			},
			/* .pid */
			/* .tid */
6285 6286 6287
		},
	};

6288
	perf_event_comm_event(&comm_event);
6289 6290
}

6291 6292 6293 6294 6295
/*
 * mmap tracking
 */

struct perf_mmap_event {
6296 6297 6298 6299
	struct vm_area_struct	*vma;

	const char		*file_name;
	int			file_size;
6300 6301 6302
	int			maj, min;
	u64			ino;
	u64			ino_generation;
6303
	u32			prot, flags;
6304 6305 6306 6307 6308 6309 6310 6311 6312

	struct {
		struct perf_event_header	header;

		u32				pid;
		u32				tid;
		u64				start;
		u64				len;
		u64				pgoff;
6313
	} event_id;
6314 6315
};

6316 6317 6318 6319 6320 6321 6322 6323
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) ||
6324
	       (executable && (event->attr.mmap || event->attr.mmap2));
6325 6326
}

6327
static void perf_event_mmap_output(struct perf_event *event,
6328
				   void *data)
6329
{
6330
	struct perf_mmap_event *mmap_event = data;
6331
	struct perf_output_handle handle;
6332
	struct perf_sample_data sample;
6333
	int size = mmap_event->event_id.header.size;
6334
	int ret;
6335

6336 6337 6338
	if (!perf_event_mmap_match(event, data))
		return;

6339 6340 6341 6342 6343
	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);
6344
		mmap_event->event_id.header.size += sizeof(mmap_event->ino_generation);
6345 6346
		mmap_event->event_id.header.size += sizeof(mmap_event->prot);
		mmap_event->event_id.header.size += sizeof(mmap_event->flags);
6347 6348
	}

6349 6350
	perf_event_header__init_id(&mmap_event->event_id.header, &sample, event);
	ret = perf_output_begin(&handle, event,
6351
				mmap_event->event_id.header.size);
6352
	if (ret)
6353
		goto out;
6354

6355 6356
	mmap_event->event_id.pid = perf_event_pid(event, current);
	mmap_event->event_id.tid = perf_event_tid(event, current);
6357

6358
	perf_output_put(&handle, mmap_event->event_id);
6359 6360 6361 6362 6363 6364

	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);
6365 6366
		perf_output_put(&handle, mmap_event->prot);
		perf_output_put(&handle, mmap_event->flags);
6367 6368
	}

6369
	__output_copy(&handle, mmap_event->file_name,
6370
				   mmap_event->file_size);
6371 6372 6373

	perf_event__output_id_sample(event, &handle, &sample);

6374
	perf_output_end(&handle);
6375 6376
out:
	mmap_event->event_id.header.size = size;
6377 6378
}

6379
static void perf_event_mmap_event(struct perf_mmap_event *mmap_event)
6380
{
6381 6382
	struct vm_area_struct *vma = mmap_event->vma;
	struct file *file = vma->vm_file;
6383 6384
	int maj = 0, min = 0;
	u64 ino = 0, gen = 0;
6385
	u32 prot = 0, flags = 0;
6386 6387 6388
	unsigned int size;
	char tmp[16];
	char *buf = NULL;
6389
	char *name;
6390

6391
	if (file) {
6392 6393
		struct inode *inode;
		dev_t dev;
6394

6395
		buf = kmalloc(PATH_MAX, GFP_KERNEL);
6396
		if (!buf) {
6397 6398
			name = "//enomem";
			goto cpy_name;
6399
		}
6400
		/*
6401
		 * d_path() works from the end of the rb backwards, so we
6402 6403 6404
		 * need to add enough zero bytes after the string to handle
		 * the 64bit alignment we do later.
		 */
M
Miklos Szeredi 已提交
6405
		name = file_path(file, buf, PATH_MAX - sizeof(u64));
6406
		if (IS_ERR(name)) {
6407 6408
			name = "//toolong";
			goto cpy_name;
6409
		}
6410 6411 6412 6413 6414 6415
		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);
6416 6417 6418 6419 6420 6421 6422 6423 6424 6425 6426 6427 6428 6429 6430 6431 6432 6433 6434 6435 6436 6437

		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;

6438
		goto got_name;
6439
	} else {
6440 6441 6442 6443 6444 6445
		if (vma->vm_ops && vma->vm_ops->name) {
			name = (char *) vma->vm_ops->name(vma);
			if (name)
				goto cpy_name;
		}

6446
		name = (char *)arch_vma_name(vma);
6447 6448
		if (name)
			goto cpy_name;
6449

6450
		if (vma->vm_start <= vma->vm_mm->start_brk &&
6451
				vma->vm_end >= vma->vm_mm->brk) {
6452 6453
			name = "[heap]";
			goto cpy_name;
6454 6455
		}
		if (vma->vm_start <= vma->vm_mm->start_stack &&
6456
				vma->vm_end >= vma->vm_mm->start_stack) {
6457 6458
			name = "[stack]";
			goto cpy_name;
6459 6460
		}

6461 6462
		name = "//anon";
		goto cpy_name;
6463 6464
	}

6465 6466 6467
cpy_name:
	strlcpy(tmp, name, sizeof(tmp));
	name = tmp;
6468
got_name:
6469 6470 6471 6472 6473 6474 6475 6476
	/*
	 * 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';
6477 6478 6479

	mmap_event->file_name = name;
	mmap_event->file_size = size;
6480 6481 6482 6483
	mmap_event->maj = maj;
	mmap_event->min = min;
	mmap_event->ino = ino;
	mmap_event->ino_generation = gen;
6484 6485
	mmap_event->prot = prot;
	mmap_event->flags = flags;
6486

6487 6488 6489
	if (!(vma->vm_flags & VM_EXEC))
		mmap_event->event_id.header.misc |= PERF_RECORD_MISC_MMAP_DATA;

6490
	mmap_event->event_id.header.size = sizeof(mmap_event->event_id) + size;
6491

6492
	perf_iterate_sb(perf_event_mmap_output,
6493 6494
		       mmap_event,
		       NULL);
6495

6496 6497 6498
	kfree(buf);
}

6499 6500 6501 6502 6503 6504 6505 6506 6507 6508 6509 6510 6511 6512 6513 6514 6515 6516 6517 6518 6519 6520 6521 6522 6523 6524 6525 6526 6527 6528 6529 6530 6531 6532 6533 6534 6535 6536 6537 6538 6539 6540 6541 6542 6543 6544 6545 6546 6547 6548 6549 6550 6551 6552 6553 6554 6555 6556 6557 6558 6559 6560 6561 6562 6563 6564 6565 6566 6567 6568 6569 6570 6571 6572 6573 6574
/*
 * 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;

6575
		perf_iterate_ctx(ctx, __perf_addr_filters_adjust, vma, true);
6576 6577 6578 6579
	}
	rcu_read_unlock();
}

6580
void perf_event_mmap(struct vm_area_struct *vma)
6581
{
6582 6583
	struct perf_mmap_event mmap_event;

6584
	if (!atomic_read(&nr_mmap_events))
6585 6586 6587
		return;

	mmap_event = (struct perf_mmap_event){
6588
		.vma	= vma,
6589 6590
		/* .file_name */
		/* .file_size */
6591
		.event_id  = {
6592
			.header = {
6593
				.type = PERF_RECORD_MMAP,
6594
				.misc = PERF_RECORD_MISC_USER,
6595 6596 6597 6598
				/* .size */
			},
			/* .pid */
			/* .tid */
6599 6600
			.start  = vma->vm_start,
			.len    = vma->vm_end - vma->vm_start,
6601
			.pgoff  = (u64)vma->vm_pgoff << PAGE_SHIFT,
6602
		},
6603 6604 6605 6606
		/* .maj (attr_mmap2 only) */
		/* .min (attr_mmap2 only) */
		/* .ino (attr_mmap2 only) */
		/* .ino_generation (attr_mmap2 only) */
6607 6608
		/* .prot (attr_mmap2 only) */
		/* .flags (attr_mmap2 only) */
6609 6610
	};

6611
	perf_addr_filters_adjust(vma);
6612
	perf_event_mmap_event(&mmap_event);
6613 6614
}

A
Alexander Shishkin 已提交
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
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);
}

6649 6650 6651 6652 6653 6654 6655 6656 6657 6658 6659 6660 6661 6662 6663 6664 6665 6666 6667 6668 6669 6670 6671 6672 6673 6674 6675 6676 6677 6678 6679 6680 6681
/*
 * 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);
}

6682 6683 6684 6685 6686 6687 6688 6689 6690 6691 6692 6693 6694 6695 6696 6697 6698 6699 6700 6701 6702 6703 6704 6705 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 6740 6741 6742 6743 6744 6745 6746 6747 6748 6749 6750 6751 6752 6753 6754 6755 6756 6757 6758 6759 6760 6761
/*
 * 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 */
		},
	};

6762
	perf_iterate_sb(perf_event_switch_output,
6763 6764 6765 6766
		       &switch_event,
		       NULL);
}

6767 6768 6769 6770
/*
 * IRQ throttle logging
 */

6771
static void perf_log_throttle(struct perf_event *event, int enable)
6772 6773
{
	struct perf_output_handle handle;
6774
	struct perf_sample_data sample;
6775 6776 6777 6778 6779
	int ret;

	struct {
		struct perf_event_header	header;
		u64				time;
6780
		u64				id;
6781
		u64				stream_id;
6782 6783
	} throttle_event = {
		.header = {
6784
			.type = PERF_RECORD_THROTTLE,
6785 6786 6787
			.misc = 0,
			.size = sizeof(throttle_event),
		},
6788
		.time		= perf_event_clock(event),
6789 6790
		.id		= primary_event_id(event),
		.stream_id	= event->id,
6791 6792
	};

6793
	if (enable)
6794
		throttle_event.header.type = PERF_RECORD_UNTHROTTLE;
6795

6796 6797 6798
	perf_event_header__init_id(&throttle_event.header, &sample, event);

	ret = perf_output_begin(&handle, event,
6799
				throttle_event.header.size);
6800 6801 6802 6803
	if (ret)
		return;

	perf_output_put(&handle, throttle_event);
6804
	perf_event__output_id_sample(event, &handle, &sample);
6805 6806 6807
	perf_output_end(&handle);
}

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
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);
}

6844
/*
6845
 * Generic event overflow handling, sampling.
6846 6847
 */

6848
static int __perf_event_overflow(struct perf_event *event,
6849 6850
				   int throttle, struct perf_sample_data *data,
				   struct pt_regs *regs)
6851
{
6852 6853
	int events = atomic_read(&event->event_limit);
	struct hw_perf_event *hwc = &event->hw;
6854
	u64 seq;
6855 6856
	int ret = 0;

6857 6858 6859 6860 6861 6862 6863
	/*
	 * Non-sampling counters might still use the PMI to fold short
	 * hardware counters, ignore those.
	 */
	if (unlikely(!is_sampling_event(event)))
		return 0;

6864 6865 6866 6867 6868 6869 6870 6871 6872
	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);
6873
			tick_dep_set_cpu(smp_processor_id(), TICK_DEP_BIT_PERF_EVENTS);
P
Peter Zijlstra 已提交
6874 6875
			hwc->interrupts = MAX_INTERRUPTS;
			perf_log_throttle(event, 0);
6876 6877
			ret = 1;
		}
6878
	}
6879

6880
	if (event->attr.freq) {
P
Peter Zijlstra 已提交
6881
		u64 now = perf_clock();
6882
		s64 delta = now - hwc->freq_time_stamp;
6883

6884
		hwc->freq_time_stamp = now;
6885

6886
		if (delta > 0 && delta < 2*TICK_NSEC)
6887
			perf_adjust_period(event, delta, hwc->last_period, true);
6888 6889
	}

6890 6891
	/*
	 * XXX event_limit might not quite work as expected on inherited
6892
	 * events
6893 6894
	 */

6895 6896
	event->pending_kill = POLL_IN;
	if (events && atomic_dec_and_test(&event->event_limit)) {
6897
		ret = 1;
6898
		event->pending_kill = POLL_HUP;
6899 6900
		event->pending_disable = 1;
		irq_work_queue(&event->pending);
6901 6902
	}

6903
	event->overflow_handler(event, data, regs);
6904

6905
	if (*perf_event_fasync(event) && event->pending_kill) {
6906 6907
		event->pending_wakeup = 1;
		irq_work_queue(&event->pending);
P
Peter Zijlstra 已提交
6908 6909
	}

6910
	return ret;
6911 6912
}

6913
int perf_event_overflow(struct perf_event *event,
6914 6915
			  struct perf_sample_data *data,
			  struct pt_regs *regs)
6916
{
6917
	return __perf_event_overflow(event, 1, data, regs);
6918 6919
}

6920
/*
6921
 * Generic software event infrastructure
6922 6923
 */

6924 6925 6926 6927 6928 6929 6930 6931 6932 6933 6934
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);

6935
/*
6936 6937
 * We directly increment event->count and keep a second value in
 * event->hw.period_left to count intervals. This period event
6938 6939 6940 6941
 * is kept in the range [-sample_period, 0] so that we can use the
 * sign as trigger.
 */

6942
u64 perf_swevent_set_period(struct perf_event *event)
6943
{
6944
	struct hw_perf_event *hwc = &event->hw;
6945 6946 6947 6948 6949
	u64 period = hwc->last_period;
	u64 nr, offset;
	s64 old, val;

	hwc->last_period = hwc->sample_period;
6950 6951

again:
6952
	old = val = local64_read(&hwc->period_left);
6953 6954
	if (val < 0)
		return 0;
6955

6956 6957 6958
	nr = div64_u64(period + val, period);
	offset = nr * period;
	val -= offset;
6959
	if (local64_cmpxchg(&hwc->period_left, old, val) != old)
6960
		goto again;
6961

6962
	return nr;
6963 6964
}

6965
static void perf_swevent_overflow(struct perf_event *event, u64 overflow,
6966
				    struct perf_sample_data *data,
6967
				    struct pt_regs *regs)
6968
{
6969
	struct hw_perf_event *hwc = &event->hw;
6970
	int throttle = 0;
6971

6972 6973
	if (!overflow)
		overflow = perf_swevent_set_period(event);
6974

6975 6976
	if (hwc->interrupts == MAX_INTERRUPTS)
		return;
6977

6978
	for (; overflow; overflow--) {
6979
		if (__perf_event_overflow(event, throttle,
6980
					    data, regs)) {
6981 6982 6983 6984 6985 6986
			/*
			 * We inhibit the overflow from happening when
			 * hwc->interrupts == MAX_INTERRUPTS.
			 */
			break;
		}
6987
		throttle = 1;
6988
	}
6989 6990
}

P
Peter Zijlstra 已提交
6991
static void perf_swevent_event(struct perf_event *event, u64 nr,
6992
			       struct perf_sample_data *data,
6993
			       struct pt_regs *regs)
6994
{
6995
	struct hw_perf_event *hwc = &event->hw;
6996

6997
	local64_add(nr, &event->count);
6998

6999 7000 7001
	if (!regs)
		return;

7002
	if (!is_sampling_event(event))
7003
		return;
7004

7005 7006 7007 7008 7009 7010
	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;

7011
	if (nr == 1 && hwc->sample_period == 1 && !event->attr.freq)
7012
		return perf_swevent_overflow(event, 1, data, regs);
7013

7014
	if (local64_add_negative(nr, &hwc->period_left))
7015
		return;
7016

7017
	perf_swevent_overflow(event, 0, data, regs);
7018 7019
}

7020 7021 7022
static int perf_exclude_event(struct perf_event *event,
			      struct pt_regs *regs)
{
P
Peter Zijlstra 已提交
7023
	if (event->hw.state & PERF_HES_STOPPED)
7024
		return 1;
P
Peter Zijlstra 已提交
7025

7026 7027 7028 7029 7030 7031 7032 7033 7034 7035 7036
	if (regs) {
		if (event->attr.exclude_user && user_mode(regs))
			return 1;

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

	return 0;
}

7037
static int perf_swevent_match(struct perf_event *event,
P
Peter Zijlstra 已提交
7038
				enum perf_type_id type,
L
Li Zefan 已提交
7039 7040 7041
				u32 event_id,
				struct perf_sample_data *data,
				struct pt_regs *regs)
7042
{
7043
	if (event->attr.type != type)
7044
		return 0;
7045

7046
	if (event->attr.config != event_id)
7047 7048
		return 0;

7049 7050
	if (perf_exclude_event(event, regs))
		return 0;
7051 7052 7053 7054

	return 1;
}

7055 7056 7057 7058 7059 7060 7061
static inline u64 swevent_hash(u64 type, u32 event_id)
{
	u64 val = event_id | (type << 32);

	return hash_64(val, SWEVENT_HLIST_BITS);
}

7062 7063
static inline struct hlist_head *
__find_swevent_head(struct swevent_hlist *hlist, u64 type, u32 event_id)
7064
{
7065 7066 7067 7068
	u64 hash = swevent_hash(type, event_id);

	return &hlist->heads[hash];
}
7069

7070 7071
/* For the read side: events when they trigger */
static inline struct hlist_head *
7072
find_swevent_head_rcu(struct swevent_htable *swhash, u64 type, u32 event_id)
7073 7074
{
	struct swevent_hlist *hlist;
7075

7076
	hlist = rcu_dereference(swhash->swevent_hlist);
7077 7078 7079
	if (!hlist)
		return NULL;

7080 7081 7082 7083 7084
	return __find_swevent_head(hlist, type, event_id);
}

/* For the event head insertion and removal in the hlist */
static inline struct hlist_head *
7085
find_swevent_head(struct swevent_htable *swhash, struct perf_event *event)
7086 7087 7088 7089 7090 7091 7092 7093 7094 7095
{
	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.
	 */
7096
	hlist = rcu_dereference_protected(swhash->swevent_hlist,
7097 7098 7099 7100 7101
					  lockdep_is_held(&event->ctx->lock));
	if (!hlist)
		return NULL;

	return __find_swevent_head(hlist, type, event_id);
7102 7103 7104
}

static void do_perf_sw_event(enum perf_type_id type, u32 event_id,
7105
				    u64 nr,
7106 7107
				    struct perf_sample_data *data,
				    struct pt_regs *regs)
7108
{
7109
	struct swevent_htable *swhash = this_cpu_ptr(&swevent_htable);
7110
	struct perf_event *event;
7111
	struct hlist_head *head;
7112

7113
	rcu_read_lock();
7114
	head = find_swevent_head_rcu(swhash, type, event_id);
7115 7116 7117
	if (!head)
		goto end;

7118
	hlist_for_each_entry_rcu(event, head, hlist_entry) {
L
Li Zefan 已提交
7119
		if (perf_swevent_match(event, type, event_id, data, regs))
7120
			perf_swevent_event(event, nr, data, regs);
7121
	}
7122 7123
end:
	rcu_read_unlock();
7124 7125
}

7126 7127
DEFINE_PER_CPU(struct pt_regs, __perf_regs[4]);

7128
int perf_swevent_get_recursion_context(void)
P
Peter Zijlstra 已提交
7129
{
7130
	struct swevent_htable *swhash = this_cpu_ptr(&swevent_htable);
P
Peter Zijlstra 已提交
7131

7132
	return get_recursion_context(swhash->recursion);
P
Peter Zijlstra 已提交
7133
}
I
Ingo Molnar 已提交
7134
EXPORT_SYMBOL_GPL(perf_swevent_get_recursion_context);
P
Peter Zijlstra 已提交
7135

7136
inline void perf_swevent_put_recursion_context(int rctx)
7137
{
7138
	struct swevent_htable *swhash = this_cpu_ptr(&swevent_htable);
7139

7140
	put_recursion_context(swhash->recursion, rctx);
7141
}
7142

7143
void ___perf_sw_event(u32 event_id, u64 nr, struct pt_regs *regs, u64 addr)
7144
{
7145
	struct perf_sample_data data;
7146

7147
	if (WARN_ON_ONCE(!regs))
7148
		return;
7149

7150
	perf_sample_data_init(&data, addr, 0);
7151
	do_perf_sw_event(PERF_TYPE_SOFTWARE, event_id, nr, &data, regs);
7152 7153 7154 7155 7156 7157 7158 7159 7160 7161 7162 7163
}

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);
7164 7165

	perf_swevent_put_recursion_context(rctx);
7166
fail:
7167
	preempt_enable_notrace();
7168 7169
}

7170
static void perf_swevent_read(struct perf_event *event)
7171 7172 7173
{
}

P
Peter Zijlstra 已提交
7174
static int perf_swevent_add(struct perf_event *event, int flags)
7175
{
7176
	struct swevent_htable *swhash = this_cpu_ptr(&swevent_htable);
7177
	struct hw_perf_event *hwc = &event->hw;
7178 7179
	struct hlist_head *head;

7180
	if (is_sampling_event(event)) {
7181
		hwc->last_period = hwc->sample_period;
7182
		perf_swevent_set_period(event);
7183
	}
7184

P
Peter Zijlstra 已提交
7185 7186
	hwc->state = !(flags & PERF_EF_START);

7187
	head = find_swevent_head(swhash, event);
P
Peter Zijlstra 已提交
7188
	if (WARN_ON_ONCE(!head))
7189 7190 7191
		return -EINVAL;

	hlist_add_head_rcu(&event->hlist_entry, head);
7192
	perf_event_update_userpage(event);
7193

7194 7195 7196
	return 0;
}

P
Peter Zijlstra 已提交
7197
static void perf_swevent_del(struct perf_event *event, int flags)
7198
{
7199
	hlist_del_rcu(&event->hlist_entry);
7200 7201
}

P
Peter Zijlstra 已提交
7202
static void perf_swevent_start(struct perf_event *event, int flags)
7203
{
P
Peter Zijlstra 已提交
7204
	event->hw.state = 0;
7205
}
I
Ingo Molnar 已提交
7206

P
Peter Zijlstra 已提交
7207
static void perf_swevent_stop(struct perf_event *event, int flags)
7208
{
P
Peter Zijlstra 已提交
7209
	event->hw.state = PERF_HES_STOPPED;
7210 7211
}

7212 7213
/* Deref the hlist from the update side */
static inline struct swevent_hlist *
7214
swevent_hlist_deref(struct swevent_htable *swhash)
7215
{
7216 7217
	return rcu_dereference_protected(swhash->swevent_hlist,
					 lockdep_is_held(&swhash->hlist_mutex));
7218 7219
}

7220
static void swevent_hlist_release(struct swevent_htable *swhash)
7221
{
7222
	struct swevent_hlist *hlist = swevent_hlist_deref(swhash);
7223

7224
	if (!hlist)
7225 7226
		return;

7227
	RCU_INIT_POINTER(swhash->swevent_hlist, NULL);
7228
	kfree_rcu(hlist, rcu_head);
7229 7230
}

7231
static void swevent_hlist_put_cpu(int cpu)
7232
{
7233
	struct swevent_htable *swhash = &per_cpu(swevent_htable, cpu);
7234

7235
	mutex_lock(&swhash->hlist_mutex);
7236

7237 7238
	if (!--swhash->hlist_refcount)
		swevent_hlist_release(swhash);
7239

7240
	mutex_unlock(&swhash->hlist_mutex);
7241 7242
}

7243
static void swevent_hlist_put(void)
7244 7245 7246 7247
{
	int cpu;

	for_each_possible_cpu(cpu)
7248
		swevent_hlist_put_cpu(cpu);
7249 7250
}

7251
static int swevent_hlist_get_cpu(int cpu)
7252
{
7253
	struct swevent_htable *swhash = &per_cpu(swevent_htable, cpu);
7254 7255
	int err = 0;

7256 7257
	mutex_lock(&swhash->hlist_mutex);
	if (!swevent_hlist_deref(swhash) && cpu_online(cpu)) {
7258 7259 7260 7261 7262 7263 7264
		struct swevent_hlist *hlist;

		hlist = kzalloc(sizeof(*hlist), GFP_KERNEL);
		if (!hlist) {
			err = -ENOMEM;
			goto exit;
		}
7265
		rcu_assign_pointer(swhash->swevent_hlist, hlist);
7266
	}
7267
	swhash->hlist_refcount++;
P
Peter Zijlstra 已提交
7268
exit:
7269
	mutex_unlock(&swhash->hlist_mutex);
7270 7271 7272 7273

	return err;
}

7274
static int swevent_hlist_get(void)
7275
{
7276
	int err, cpu, failed_cpu;
7277 7278 7279

	get_online_cpus();
	for_each_possible_cpu(cpu) {
7280
		err = swevent_hlist_get_cpu(cpu);
7281 7282 7283 7284 7285 7286 7287 7288
		if (err) {
			failed_cpu = cpu;
			goto fail;
		}
	}
	put_online_cpus();

	return 0;
P
Peter Zijlstra 已提交
7289
fail:
7290 7291 7292
	for_each_possible_cpu(cpu) {
		if (cpu == failed_cpu)
			break;
7293
		swevent_hlist_put_cpu(cpu);
7294 7295 7296 7297 7298 7299
	}

	put_online_cpus();
	return err;
}

7300
struct static_key perf_swevent_enabled[PERF_COUNT_SW_MAX];
7301

7302 7303 7304
static void sw_perf_event_destroy(struct perf_event *event)
{
	u64 event_id = event->attr.config;
7305

7306 7307
	WARN_ON(event->parent);

7308
	static_key_slow_dec(&perf_swevent_enabled[event_id]);
7309
	swevent_hlist_put();
7310 7311 7312 7313
}

static int perf_swevent_init(struct perf_event *event)
{
7314
	u64 event_id = event->attr.config;
7315 7316 7317 7318

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

7319 7320 7321 7322 7323 7324
	/*
	 * no branch sampling for software events
	 */
	if (has_branch_stack(event))
		return -EOPNOTSUPP;

7325 7326 7327 7328 7329 7330 7331 7332 7333
	switch (event_id) {
	case PERF_COUNT_SW_CPU_CLOCK:
	case PERF_COUNT_SW_TASK_CLOCK:
		return -ENOENT;

	default:
		break;
	}

7334
	if (event_id >= PERF_COUNT_SW_MAX)
7335 7336 7337 7338 7339
		return -ENOENT;

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

7340
		err = swevent_hlist_get();
7341 7342 7343
		if (err)
			return err;

7344
		static_key_slow_inc(&perf_swevent_enabled[event_id]);
7345 7346 7347 7348 7349 7350 7351
		event->destroy = sw_perf_event_destroy;
	}

	return 0;
}

static struct pmu perf_swevent = {
7352
	.task_ctx_nr	= perf_sw_context,
7353

7354 7355
	.capabilities	= PERF_PMU_CAP_NO_NMI,

7356
	.event_init	= perf_swevent_init,
P
Peter Zijlstra 已提交
7357 7358 7359 7360
	.add		= perf_swevent_add,
	.del		= perf_swevent_del,
	.start		= perf_swevent_start,
	.stop		= perf_swevent_stop,
7361 7362 7363
	.read		= perf_swevent_read,
};

7364 7365
#ifdef CONFIG_EVENT_TRACING

7366 7367 7368 7369 7370
static int perf_tp_filter_match(struct perf_event *event,
				struct perf_sample_data *data)
{
	void *record = data->raw->data;

7371 7372 7373 7374
	/* only top level events have filters set */
	if (event->parent)
		event = event->parent;

7375 7376 7377 7378 7379 7380 7381 7382 7383
	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)
{
7384 7385
	if (event->hw.state & PERF_HES_STOPPED)
		return 0;
7386 7387 7388 7389
	/*
	 * All tracepoints are from kernel-space.
	 */
	if (event->attr.exclude_kernel)
7390 7391 7392 7393 7394 7395 7396 7397 7398
		return 0;

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

	return 1;
}

void perf_tp_event(u64 addr, u64 count, void *record, int entry_size,
7399 7400
		   struct pt_regs *regs, struct hlist_head *head, int rctx,
		   struct task_struct *task)
7401 7402
{
	struct perf_sample_data data;
7403 7404
	struct perf_event *event;

7405 7406 7407 7408 7409
	struct perf_raw_record raw = {
		.size = entry_size,
		.data = record,
	};

7410
	perf_sample_data_init(&data, addr, 0);
7411 7412
	data.raw = &raw;

7413
	hlist_for_each_entry_rcu(event, head, hlist_entry) {
7414
		if (perf_tp_event_match(event, &data, regs))
7415
			perf_swevent_event(event, count, &data, regs);
7416
	}
7417

7418 7419 7420 7421 7422 7423 7424 7425 7426 7427 7428 7429 7430 7431 7432 7433 7434 7435 7436 7437 7438 7439 7440 7441 7442
	/*
	 * 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();
	}

7443
	perf_swevent_put_recursion_context(rctx);
7444 7445 7446
}
EXPORT_SYMBOL_GPL(perf_tp_event);

7447
static void tp_perf_event_destroy(struct perf_event *event)
7448
{
7449
	perf_trace_destroy(event);
7450 7451
}

7452
static int perf_tp_event_init(struct perf_event *event)
7453
{
7454 7455
	int err;

7456 7457 7458
	if (event->attr.type != PERF_TYPE_TRACEPOINT)
		return -ENOENT;

7459 7460 7461 7462 7463 7464
	/*
	 * no branch sampling for tracepoint events
	 */
	if (has_branch_stack(event))
		return -EOPNOTSUPP;

7465 7466
	err = perf_trace_init(event);
	if (err)
7467
		return err;
7468

7469
	event->destroy = tp_perf_event_destroy;
7470

7471 7472 7473 7474
	return 0;
}

static struct pmu perf_tracepoint = {
7475 7476
	.task_ctx_nr	= perf_sw_context,

7477
	.event_init	= perf_tp_event_init,
P
Peter Zijlstra 已提交
7478 7479 7480 7481
	.add		= perf_trace_add,
	.del		= perf_trace_del,
	.start		= perf_swevent_start,
	.stop		= perf_swevent_stop,
7482 7483 7484 7485 7486
	.read		= perf_swevent_read,
};

static inline void perf_tp_register(void)
{
P
Peter Zijlstra 已提交
7487
	perf_pmu_register(&perf_tracepoint, "tracepoint", PERF_TYPE_TRACEPOINT);
7488
}
L
Li Zefan 已提交
7489 7490 7491 7492 7493 7494

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

7495 7496 7497 7498 7499 7500 7501 7502 7503 7504
static int perf_event_set_bpf_prog(struct perf_event *event, u32 prog_fd)
{
	struct bpf_prog *prog;

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

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

7505 7506
	if (!(event->tp_event->flags & TRACE_EVENT_FL_UKPROBE))
		/* bpf programs can only be attached to u/kprobes */
7507 7508 7509 7510 7511 7512
		return -EINVAL;

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

7513
	if (prog->type != BPF_PROG_TYPE_KPROBE) {
7514 7515 7516 7517 7518 7519 7520 7521 7522 7523 7524 7525 7526 7527 7528 7529 7530 7531 7532 7533 7534 7535 7536 7537
		/* valid fd, but invalid bpf program type */
		bpf_prog_put(prog);
		return -EINVAL;
	}

	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;
		bpf_prog_put(prog);
	}
}

7538
#else
L
Li Zefan 已提交
7539

7540
static inline void perf_tp_register(void)
7541 7542
{
}
L
Li Zefan 已提交
7543 7544 7545 7546 7547

static void perf_event_free_filter(struct perf_event *event)
{
}

7548 7549 7550 7551 7552 7553 7554 7555
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)
{
}
7556
#endif /* CONFIG_EVENT_TRACING */
7557

7558
#ifdef CONFIG_HAVE_HW_BREAKPOINT
7559
void perf_bp_event(struct perf_event *bp, void *data)
7560
{
7561 7562 7563
	struct perf_sample_data sample;
	struct pt_regs *regs = data;

7564
	perf_sample_data_init(&sample, bp->attr.bp_addr, 0);
7565

P
Peter Zijlstra 已提交
7566
	if (!bp->hw.state && !perf_exclude_event(bp, regs))
7567
		perf_swevent_event(bp, 1, &sample, regs);
7568 7569 7570
}
#endif

7571 7572 7573 7574 7575 7576 7577 7578 7579 7580 7581 7582 7583 7584 7585 7586 7587 7588 7589 7590 7591 7592 7593 7594 7595 7596 7597 7598 7599 7600 7601 7602 7603 7604 7605 7606 7607 7608 7609 7610 7611 7612 7613 7614 7615 7616 7617 7618 7619 7620 7621 7622 7623 7624 7625 7626 7627 7628 7629 7630 7631 7632 7633 7634 7635 7636 7637 7638 7639 7640 7641 7642 7643 7644 7645 7646 7647 7648 7649 7650 7651 7652 7653 7654 7655 7656 7657 7658 7659 7660 7661 7662 7663 7664 7665 7666 7667 7668 7669 7670 7671 7672 7673 7674 7675 7676 7677 7678 7679 7680 7681 7682 7683 7684 7685 7686 7687 7688 7689 7690 7691 7692 7693 7694 7695 7696 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
/*
 * 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;
}

7927 7928 7929 7930 7931
static int perf_event_set_filter(struct perf_event *event, void __user *arg)
{
	char *filter_str;
	int ret = -EINVAL;

7932 7933 7934
	if ((event->attr.type != PERF_TYPE_TRACEPOINT ||
	    !IS_ENABLED(CONFIG_EVENT_TRACING)) &&
	    !has_addr_filter(event))
7935 7936 7937 7938 7939 7940 7941 7942 7943 7944
		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);
7945 7946
	else if (has_addr_filter(event))
		ret = perf_event_set_addr_filter(event, filter_str);
7947 7948 7949 7950 7951

	kfree(filter_str);
	return ret;
}

7952 7953 7954
/*
 * hrtimer based swevent callback
 */
7955

7956
static enum hrtimer_restart perf_swevent_hrtimer(struct hrtimer *hrtimer)
7957
{
7958 7959 7960 7961 7962
	enum hrtimer_restart ret = HRTIMER_RESTART;
	struct perf_sample_data data;
	struct pt_regs *regs;
	struct perf_event *event;
	u64 period;
7963

7964
	event = container_of(hrtimer, struct perf_event, hw.hrtimer);
P
Peter Zijlstra 已提交
7965 7966 7967 7968

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

7969
	event->pmu->read(event);
7970

7971
	perf_sample_data_init(&data, 0, event->hw.last_period);
7972 7973 7974
	regs = get_irq_regs();

	if (regs && !perf_exclude_event(event, regs)) {
7975
		if (!(event->attr.exclude_idle && is_idle_task(current)))
7976
			if (__perf_event_overflow(event, 1, &data, regs))
7977 7978
				ret = HRTIMER_NORESTART;
	}
7979

7980 7981
	period = max_t(u64, 10000, event->hw.sample_period);
	hrtimer_forward_now(hrtimer, ns_to_ktime(period));
7982

7983
	return ret;
7984 7985
}

7986
static void perf_swevent_start_hrtimer(struct perf_event *event)
7987
{
7988
	struct hw_perf_event *hwc = &event->hw;
7989 7990 7991 7992
	s64 period;

	if (!is_sampling_event(event))
		return;
7993

7994 7995 7996 7997
	period = local64_read(&hwc->period_left);
	if (period) {
		if (period < 0)
			period = 10000;
P
Peter Zijlstra 已提交
7998

7999 8000 8001 8002
		local64_set(&hwc->period_left, 0);
	} else {
		period = max_t(u64, 10000, hwc->sample_period);
	}
8003 8004
	hrtimer_start(&hwc->hrtimer, ns_to_ktime(period),
		      HRTIMER_MODE_REL_PINNED);
8005
}
8006 8007

static void perf_swevent_cancel_hrtimer(struct perf_event *event)
8008
{
8009 8010
	struct hw_perf_event *hwc = &event->hw;

8011
	if (is_sampling_event(event)) {
8012
		ktime_t remaining = hrtimer_get_remaining(&hwc->hrtimer);
P
Peter Zijlstra 已提交
8013
		local64_set(&hwc->period_left, ktime_to_ns(remaining));
8014 8015 8016

		hrtimer_cancel(&hwc->hrtimer);
	}
8017 8018
}

P
Peter Zijlstra 已提交
8019 8020 8021 8022 8023 8024 8025 8026 8027 8028 8029 8030 8031 8032 8033 8034 8035 8036 8037 8038
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);
8039
		hwc->last_period = hwc->sample_period;
P
Peter Zijlstra 已提交
8040 8041 8042 8043
		event->attr.freq = 0;
	}
}

8044 8045 8046 8047 8048
/*
 * Software event: cpu wall time clock
 */

static void cpu_clock_event_update(struct perf_event *event)
8049
{
8050 8051 8052
	s64 prev;
	u64 now;

P
Peter Zijlstra 已提交
8053
	now = local_clock();
8054 8055
	prev = local64_xchg(&event->hw.prev_count, now);
	local64_add(now - prev, &event->count);
8056 8057
}

P
Peter Zijlstra 已提交
8058
static void cpu_clock_event_start(struct perf_event *event, int flags)
8059
{
P
Peter Zijlstra 已提交
8060
	local64_set(&event->hw.prev_count, local_clock());
8061 8062 8063
	perf_swevent_start_hrtimer(event);
}

P
Peter Zijlstra 已提交
8064
static void cpu_clock_event_stop(struct perf_event *event, int flags)
8065
{
8066 8067 8068
	perf_swevent_cancel_hrtimer(event);
	cpu_clock_event_update(event);
}
8069

P
Peter Zijlstra 已提交
8070 8071 8072 8073
static int cpu_clock_event_add(struct perf_event *event, int flags)
{
	if (flags & PERF_EF_START)
		cpu_clock_event_start(event, flags);
8074
	perf_event_update_userpage(event);
P
Peter Zijlstra 已提交
8075 8076 8077 8078 8079 8080 8081 8082 8083

	return 0;
}

static void cpu_clock_event_del(struct perf_event *event, int flags)
{
	cpu_clock_event_stop(event, flags);
}

8084 8085 8086 8087
static void cpu_clock_event_read(struct perf_event *event)
{
	cpu_clock_event_update(event);
}
8088

8089 8090 8091 8092 8093 8094 8095 8096
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;

8097 8098 8099 8100 8101 8102
	/*
	 * no branch sampling for software events
	 */
	if (has_branch_stack(event))
		return -EOPNOTSUPP;

P
Peter Zijlstra 已提交
8103 8104
	perf_swevent_init_hrtimer(event);

8105
	return 0;
8106 8107
}

8108
static struct pmu perf_cpu_clock = {
8109 8110
	.task_ctx_nr	= perf_sw_context,

8111 8112
	.capabilities	= PERF_PMU_CAP_NO_NMI,

8113
	.event_init	= cpu_clock_event_init,
P
Peter Zijlstra 已提交
8114 8115 8116 8117
	.add		= cpu_clock_event_add,
	.del		= cpu_clock_event_del,
	.start		= cpu_clock_event_start,
	.stop		= cpu_clock_event_stop,
8118 8119 8120 8121 8122 8123 8124 8125
	.read		= cpu_clock_event_read,
};

/*
 * Software event: task time clock
 */

static void task_clock_event_update(struct perf_event *event, u64 now)
8126
{
8127 8128
	u64 prev;
	s64 delta;
8129

8130 8131 8132 8133
	prev = local64_xchg(&event->hw.prev_count, now);
	delta = now - prev;
	local64_add(delta, &event->count);
}
8134

P
Peter Zijlstra 已提交
8135
static void task_clock_event_start(struct perf_event *event, int flags)
8136
{
P
Peter Zijlstra 已提交
8137
	local64_set(&event->hw.prev_count, event->ctx->time);
8138 8139 8140
	perf_swevent_start_hrtimer(event);
}

P
Peter Zijlstra 已提交
8141
static void task_clock_event_stop(struct perf_event *event, int flags)
8142 8143 8144
{
	perf_swevent_cancel_hrtimer(event);
	task_clock_event_update(event, event->ctx->time);
P
Peter Zijlstra 已提交
8145 8146 8147 8148 8149 8150
}

static int task_clock_event_add(struct perf_event *event, int flags)
{
	if (flags & PERF_EF_START)
		task_clock_event_start(event, flags);
8151
	perf_event_update_userpage(event);
8152

P
Peter Zijlstra 已提交
8153 8154 8155 8156 8157 8158
	return 0;
}

static void task_clock_event_del(struct perf_event *event, int flags)
{
	task_clock_event_stop(event, PERF_EF_UPDATE);
8159 8160 8161 8162
}

static void task_clock_event_read(struct perf_event *event)
{
8163 8164 8165
	u64 now = perf_clock();
	u64 delta = now - event->ctx->timestamp;
	u64 time = event->ctx->time + delta;
8166 8167 8168 8169 8170

	task_clock_event_update(event, time);
}

static int task_clock_event_init(struct perf_event *event)
L
Li Zefan 已提交
8171
{
8172 8173 8174 8175 8176 8177
	if (event->attr.type != PERF_TYPE_SOFTWARE)
		return -ENOENT;

	if (event->attr.config != PERF_COUNT_SW_TASK_CLOCK)
		return -ENOENT;

8178 8179 8180 8181 8182 8183
	/*
	 * no branch sampling for software events
	 */
	if (has_branch_stack(event))
		return -EOPNOTSUPP;

P
Peter Zijlstra 已提交
8184 8185
	perf_swevent_init_hrtimer(event);

8186
	return 0;
L
Li Zefan 已提交
8187 8188
}

8189
static struct pmu perf_task_clock = {
8190 8191
	.task_ctx_nr	= perf_sw_context,

8192 8193
	.capabilities	= PERF_PMU_CAP_NO_NMI,

8194
	.event_init	= task_clock_event_init,
P
Peter Zijlstra 已提交
8195 8196 8197 8198
	.add		= task_clock_event_add,
	.del		= task_clock_event_del,
	.start		= task_clock_event_start,
	.stop		= task_clock_event_stop,
8199 8200
	.read		= task_clock_event_read,
};
L
Li Zefan 已提交
8201

P
Peter Zijlstra 已提交
8202
static void perf_pmu_nop_void(struct pmu *pmu)
8203 8204
{
}
L
Li Zefan 已提交
8205

8206 8207 8208 8209
static void perf_pmu_nop_txn(struct pmu *pmu, unsigned int flags)
{
}

P
Peter Zijlstra 已提交
8210
static int perf_pmu_nop_int(struct pmu *pmu)
L
Li Zefan 已提交
8211
{
P
Peter Zijlstra 已提交
8212
	return 0;
L
Li Zefan 已提交
8213 8214
}

8215
static DEFINE_PER_CPU(unsigned int, nop_txn_flags);
8216 8217

static void perf_pmu_start_txn(struct pmu *pmu, unsigned int flags)
L
Li Zefan 已提交
8218
{
8219 8220 8221 8222 8223
	__this_cpu_write(nop_txn_flags, flags);

	if (flags & ~PERF_PMU_TXN_ADD)
		return;

P
Peter Zijlstra 已提交
8224
	perf_pmu_disable(pmu);
L
Li Zefan 已提交
8225 8226
}

P
Peter Zijlstra 已提交
8227 8228
static int perf_pmu_commit_txn(struct pmu *pmu)
{
8229 8230 8231 8232 8233 8234 8235
	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
8236 8237 8238
	perf_pmu_enable(pmu);
	return 0;
}
8239

P
Peter Zijlstra 已提交
8240
static void perf_pmu_cancel_txn(struct pmu *pmu)
8241
{
8242 8243 8244 8245 8246 8247 8248
	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
8249
	perf_pmu_enable(pmu);
8250 8251
}

8252 8253
static int perf_event_idx_default(struct perf_event *event)
{
8254
	return 0;
8255 8256
}

P
Peter Zijlstra 已提交
8257 8258 8259 8260
/*
 * Ensures all contexts with the same task_ctx_nr have the same
 * pmu_cpu_context too.
 */
8261
static struct perf_cpu_context __percpu *find_pmu_context(int ctxn)
8262
{
P
Peter Zijlstra 已提交
8263
	struct pmu *pmu;
8264

P
Peter Zijlstra 已提交
8265 8266
	if (ctxn < 0)
		return NULL;
8267

P
Peter Zijlstra 已提交
8268 8269 8270 8271
	list_for_each_entry(pmu, &pmus, entry) {
		if (pmu->task_ctx_nr == ctxn)
			return pmu->pmu_cpu_context;
	}
8272

P
Peter Zijlstra 已提交
8273
	return NULL;
8274 8275
}

8276
static void update_pmu_context(struct pmu *pmu, struct pmu *old_pmu)
8277
{
8278 8279 8280 8281 8282 8283 8284
	int cpu;

	for_each_possible_cpu(cpu) {
		struct perf_cpu_context *cpuctx;

		cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);

8285 8286
		if (cpuctx->unique_pmu == old_pmu)
			cpuctx->unique_pmu = pmu;
8287 8288 8289 8290 8291 8292
	}
}

static void free_pmu_context(struct pmu *pmu)
{
	struct pmu *i;
8293

P
Peter Zijlstra 已提交
8294
	mutex_lock(&pmus_lock);
8295
	/*
P
Peter Zijlstra 已提交
8296
	 * Like a real lame refcount.
8297
	 */
8298 8299 8300
	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
8301
			goto out;
8302
		}
P
Peter Zijlstra 已提交
8303
	}
8304

8305
	free_percpu(pmu->pmu_cpu_context);
P
Peter Zijlstra 已提交
8306 8307
out:
	mutex_unlock(&pmus_lock);
8308
}
8309 8310 8311 8312 8313 8314 8315 8316 8317 8318 8319 8320 8321 8322

/*
 * 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
8323
static struct idr pmu_idr;
8324

P
Peter Zijlstra 已提交
8325 8326 8327 8328 8329 8330 8331
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);
}
8332
static DEVICE_ATTR_RO(type);
P
Peter Zijlstra 已提交
8333

8334 8335 8336 8337 8338 8339 8340 8341 8342 8343
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);
}

8344 8345
static DEFINE_MUTEX(mux_interval_mutex);

8346 8347 8348 8349 8350 8351 8352 8353 8354 8355 8356 8357 8358 8359 8360 8361 8362 8363 8364
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;

8365
	mutex_lock(&mux_interval_mutex);
8366 8367 8368
	pmu->hrtimer_interval_ms = timer;

	/* update all cpuctx for this PMU */
8369 8370
	get_online_cpus();
	for_each_online_cpu(cpu) {
8371 8372 8373 8374
		struct perf_cpu_context *cpuctx;
		cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
		cpuctx->hrtimer_interval = ns_to_ktime(NSEC_PER_MSEC * timer);

8375 8376
		cpu_function_call(cpu,
			(remote_function_f)perf_mux_hrtimer_restart, cpuctx);
8377
	}
8378 8379
	put_online_cpus();
	mutex_unlock(&mux_interval_mutex);
8380 8381 8382

	return count;
}
8383
static DEVICE_ATTR_RW(perf_event_mux_interval_ms);
8384

8385 8386 8387 8388
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
8389
};
8390
ATTRIBUTE_GROUPS(pmu_dev);
P
Peter Zijlstra 已提交
8391 8392 8393 8394

static int pmu_bus_running;
static struct bus_type pmu_bus = {
	.name		= "event_source",
8395
	.dev_groups	= pmu_dev_groups,
P
Peter Zijlstra 已提交
8396 8397 8398 8399 8400 8401 8402 8403 8404 8405 8406 8407 8408 8409 8410
};

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;

8411
	pmu->dev->groups = pmu->attr_groups;
P
Peter Zijlstra 已提交
8412 8413 8414 8415 8416 8417 8418 8419 8420 8421 8422 8423
	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;

8424 8425 8426 8427 8428 8429 8430
	/* 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
8431 8432 8433
out:
	return ret;

8434 8435 8436
del_dev:
	device_del(pmu->dev);

P
Peter Zijlstra 已提交
8437 8438 8439 8440 8441
free_dev:
	put_device(pmu->dev);
	goto out;
}

8442
static struct lock_class_key cpuctx_mutex;
8443
static struct lock_class_key cpuctx_lock;
8444

8445
int perf_pmu_register(struct pmu *pmu, const char *name, int type)
8446
{
P
Peter Zijlstra 已提交
8447
	int cpu, ret;
8448

8449
	mutex_lock(&pmus_lock);
P
Peter Zijlstra 已提交
8450 8451 8452 8453
	ret = -ENOMEM;
	pmu->pmu_disable_count = alloc_percpu(int);
	if (!pmu->pmu_disable_count)
		goto unlock;
8454

P
Peter Zijlstra 已提交
8455 8456 8457 8458 8459 8460
	pmu->type = -1;
	if (!name)
		goto skip_type;
	pmu->name = name;

	if (type < 0) {
T
Tejun Heo 已提交
8461 8462 8463
		type = idr_alloc(&pmu_idr, pmu, PERF_TYPE_MAX, 0, GFP_KERNEL);
		if (type < 0) {
			ret = type;
P
Peter Zijlstra 已提交
8464 8465 8466 8467 8468
			goto free_pdc;
		}
	}
	pmu->type = type;

P
Peter Zijlstra 已提交
8469 8470 8471 8472 8473 8474
	if (pmu_bus_running) {
		ret = pmu_dev_alloc(pmu);
		if (ret)
			goto free_idr;
	}

P
Peter Zijlstra 已提交
8475
skip_type:
8476 8477 8478
	if (pmu->task_ctx_nr == perf_hw_context) {
		static int hw_context_taken = 0;

8479 8480 8481 8482 8483 8484 8485
		/*
		 * 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)))
8486 8487 8488 8489 8490
			pmu->task_ctx_nr = perf_invalid_context;

		hw_context_taken = 1;
	}

P
Peter Zijlstra 已提交
8491 8492 8493
	pmu->pmu_cpu_context = find_pmu_context(pmu->task_ctx_nr);
	if (pmu->pmu_cpu_context)
		goto got_cpu_context;
8494

W
Wei Yongjun 已提交
8495
	ret = -ENOMEM;
P
Peter Zijlstra 已提交
8496 8497
	pmu->pmu_cpu_context = alloc_percpu(struct perf_cpu_context);
	if (!pmu->pmu_cpu_context)
P
Peter Zijlstra 已提交
8498
		goto free_dev;
8499

P
Peter Zijlstra 已提交
8500 8501 8502 8503
	for_each_possible_cpu(cpu) {
		struct perf_cpu_context *cpuctx;

		cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
8504
		__perf_event_init_context(&cpuctx->ctx);
8505
		lockdep_set_class(&cpuctx->ctx.mutex, &cpuctx_mutex);
8506
		lockdep_set_class(&cpuctx->ctx.lock, &cpuctx_lock);
P
Peter Zijlstra 已提交
8507
		cpuctx->ctx.pmu = pmu;
8508

8509
		__perf_mux_hrtimer_init(cpuctx, cpu);
8510

8511
		cpuctx->unique_pmu = pmu;
P
Peter Zijlstra 已提交
8512
	}
8513

P
Peter Zijlstra 已提交
8514
got_cpu_context:
P
Peter Zijlstra 已提交
8515 8516 8517 8518 8519 8520 8521 8522 8523 8524 8525
	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 {
8526
			pmu->start_txn  = perf_pmu_nop_txn;
P
Peter Zijlstra 已提交
8527 8528
			pmu->commit_txn = perf_pmu_nop_int;
			pmu->cancel_txn = perf_pmu_nop_void;
8529
		}
8530
	}
8531

P
Peter Zijlstra 已提交
8532 8533 8534 8535 8536
	if (!pmu->pmu_enable) {
		pmu->pmu_enable  = perf_pmu_nop_void;
		pmu->pmu_disable = perf_pmu_nop_void;
	}

8537 8538 8539
	if (!pmu->event_idx)
		pmu->event_idx = perf_event_idx_default;

8540
	list_add_rcu(&pmu->entry, &pmus);
8541
	atomic_set(&pmu->exclusive_cnt, 0);
P
Peter Zijlstra 已提交
8542 8543
	ret = 0;
unlock:
8544 8545
	mutex_unlock(&pmus_lock);

P
Peter Zijlstra 已提交
8546
	return ret;
P
Peter Zijlstra 已提交
8547

P
Peter Zijlstra 已提交
8548 8549 8550 8551
free_dev:
	device_del(pmu->dev);
	put_device(pmu->dev);

P
Peter Zijlstra 已提交
8552 8553 8554 8555
free_idr:
	if (pmu->type >= PERF_TYPE_MAX)
		idr_remove(&pmu_idr, pmu->type);

P
Peter Zijlstra 已提交
8556 8557 8558
free_pdc:
	free_percpu(pmu->pmu_disable_count);
	goto unlock;
8559
}
8560
EXPORT_SYMBOL_GPL(perf_pmu_register);
8561

8562
void perf_pmu_unregister(struct pmu *pmu)
8563
{
8564 8565 8566
	mutex_lock(&pmus_lock);
	list_del_rcu(&pmu->entry);
	mutex_unlock(&pmus_lock);
8567

8568
	/*
P
Peter Zijlstra 已提交
8569 8570
	 * We dereference the pmu list under both SRCU and regular RCU, so
	 * synchronize against both of those.
8571
	 */
8572
	synchronize_srcu(&pmus_srcu);
P
Peter Zijlstra 已提交
8573
	synchronize_rcu();
8574

P
Peter Zijlstra 已提交
8575
	free_percpu(pmu->pmu_disable_count);
P
Peter Zijlstra 已提交
8576 8577
	if (pmu->type >= PERF_TYPE_MAX)
		idr_remove(&pmu_idr, pmu->type);
8578 8579
	if (pmu->nr_addr_filters)
		device_remove_file(pmu->dev, &dev_attr_nr_addr_filters);
P
Peter Zijlstra 已提交
8580 8581
	device_del(pmu->dev);
	put_device(pmu->dev);
8582
	free_pmu_context(pmu);
8583
}
8584
EXPORT_SYMBOL_GPL(perf_pmu_unregister);
8585

8586 8587
static int perf_try_init_event(struct pmu *pmu, struct perf_event *event)
{
P
Peter Zijlstra 已提交
8588
	struct perf_event_context *ctx = NULL;
8589 8590 8591 8592
	int ret;

	if (!try_module_get(pmu->module))
		return -ENODEV;
P
Peter Zijlstra 已提交
8593 8594

	if (event->group_leader != event) {
8595 8596 8597 8598 8599 8600
		/*
		 * 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
8601 8602 8603
		BUG_ON(!ctx);
	}

8604 8605
	event->pmu = pmu;
	ret = pmu->event_init(event);
P
Peter Zijlstra 已提交
8606 8607 8608 8609

	if (ctx)
		perf_event_ctx_unlock(event->group_leader, ctx);

8610 8611 8612 8613 8614 8615
	if (ret)
		module_put(pmu->module);

	return ret;
}

8616
static struct pmu *perf_init_event(struct perf_event *event)
8617 8618 8619
{
	struct pmu *pmu = NULL;
	int idx;
8620
	int ret;
8621 8622

	idx = srcu_read_lock(&pmus_srcu);
P
Peter Zijlstra 已提交
8623 8624 8625 8626

	rcu_read_lock();
	pmu = idr_find(&pmu_idr, event->attr.type);
	rcu_read_unlock();
8627
	if (pmu) {
8628
		ret = perf_try_init_event(pmu, event);
8629 8630
		if (ret)
			pmu = ERR_PTR(ret);
P
Peter Zijlstra 已提交
8631
		goto unlock;
8632
	}
P
Peter Zijlstra 已提交
8633

8634
	list_for_each_entry_rcu(pmu, &pmus, entry) {
8635
		ret = perf_try_init_event(pmu, event);
8636
		if (!ret)
P
Peter Zijlstra 已提交
8637
			goto unlock;
8638

8639 8640
		if (ret != -ENOENT) {
			pmu = ERR_PTR(ret);
P
Peter Zijlstra 已提交
8641
			goto unlock;
8642
		}
8643
	}
P
Peter Zijlstra 已提交
8644 8645
	pmu = ERR_PTR(-ENOENT);
unlock:
8646
	srcu_read_unlock(&pmus_srcu, idx);
8647

8648
	return pmu;
8649 8650
}

8651 8652 8653 8654 8655 8656 8657 8658 8659
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);
}

8660 8661 8662 8663 8664 8665 8666
/*
 * 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.
 */
8667 8668 8669 8670 8671 8672 8673 8674 8675 8676 8677 8678 8679 8680 8681 8682 8683
static void account_pmu_sb_event(struct perf_event *event)
{
	struct perf_event_attr *attr = &event->attr;

	if (event->parent)
		return;

	if (event->attach_state & PERF_ATTACH_TASK)
		return;

	if (attr->mmap || attr->mmap_data || attr->mmap2 ||
	    attr->comm || attr->comm_exec ||
	    attr->task ||
	    attr->context_switch)
		attach_sb_event(event);
}

8684 8685 8686 8687 8688 8689 8690 8691 8692
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));
}

8693 8694 8695 8696 8697 8698 8699 8700 8701 8702 8703 8704 8705 8706 8707 8708 8709 8710 8711 8712 8713
/* 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);
}


8714 8715
static void account_event(struct perf_event *event)
{
8716 8717
	bool inc = false;

8718 8719 8720
	if (event->parent)
		return;

8721
	if (event->attach_state & PERF_ATTACH_TASK)
8722
		inc = true;
8723 8724 8725 8726 8727 8728
	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);
8729 8730
	if (event->attr.freq)
		account_freq_event();
8731 8732
	if (event->attr.context_switch) {
		atomic_inc(&nr_switch_events);
8733
		inc = true;
8734
	}
8735
	if (has_branch_stack(event))
8736
		inc = true;
8737
	if (is_cgroup_event(event))
8738 8739
		inc = true;

8740 8741 8742 8743 8744 8745 8746 8747 8748 8749 8750 8751 8752 8753 8754 8755 8756 8757 8758 8759 8760 8761
	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:
8762 8763

	account_event_cpu(event, event->cpu);
8764 8765

	account_pmu_sb_event(event);
8766 8767
}

T
Thomas Gleixner 已提交
8768
/*
8769
 * Allocate and initialize a event structure
T
Thomas Gleixner 已提交
8770
 */
8771
static struct perf_event *
8772
perf_event_alloc(struct perf_event_attr *attr, int cpu,
8773 8774 8775
		 struct task_struct *task,
		 struct perf_event *group_leader,
		 struct perf_event *parent_event,
8776
		 perf_overflow_handler_t overflow_handler,
8777
		 void *context, int cgroup_fd)
T
Thomas Gleixner 已提交
8778
{
P
Peter Zijlstra 已提交
8779
	struct pmu *pmu;
8780 8781
	struct perf_event *event;
	struct hw_perf_event *hwc;
8782
	long err = -EINVAL;
T
Thomas Gleixner 已提交
8783

8784 8785 8786 8787 8788
	if ((unsigned)cpu >= nr_cpu_ids) {
		if (!task || cpu != -1)
			return ERR_PTR(-EINVAL);
	}

8789
	event = kzalloc(sizeof(*event), GFP_KERNEL);
8790
	if (!event)
8791
		return ERR_PTR(-ENOMEM);
T
Thomas Gleixner 已提交
8792

8793
	/*
8794
	 * Single events are their own group leaders, with an
8795 8796 8797
	 * empty sibling list:
	 */
	if (!group_leader)
8798
		group_leader = event;
8799

8800 8801
	mutex_init(&event->child_mutex);
	INIT_LIST_HEAD(&event->child_list);
8802

8803 8804 8805
	INIT_LIST_HEAD(&event->group_entry);
	INIT_LIST_HEAD(&event->event_entry);
	INIT_LIST_HEAD(&event->sibling_list);
8806
	INIT_LIST_HEAD(&event->rb_entry);
8807
	INIT_LIST_HEAD(&event->active_entry);
8808
	INIT_LIST_HEAD(&event->addr_filters.list);
8809 8810
	INIT_HLIST_NODE(&event->hlist_entry);

8811

8812
	init_waitqueue_head(&event->waitq);
8813
	init_irq_work(&event->pending, perf_pending_event);
T
Thomas Gleixner 已提交
8814

8815
	mutex_init(&event->mmap_mutex);
8816
	raw_spin_lock_init(&event->addr_filters.lock);
8817

8818
	atomic_long_set(&event->refcount, 1);
8819 8820 8821 8822 8823
	event->cpu		= cpu;
	event->attr		= *attr;
	event->group_leader	= group_leader;
	event->pmu		= NULL;
	event->oncpu		= -1;
8824

8825
	event->parent		= parent_event;
8826

8827
	event->ns		= get_pid_ns(task_active_pid_ns(current));
8828
	event->id		= atomic64_inc_return(&perf_event_id);
8829

8830
	event->state		= PERF_EVENT_STATE_INACTIVE;
8831

8832 8833 8834
	if (task) {
		event->attach_state = PERF_ATTACH_TASK;
		/*
8835 8836 8837
		 * 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.
8838
		 */
8839
		event->hw.target = task;
8840 8841
	}

8842 8843 8844 8845
	event->clock = &local_clock;
	if (parent_event)
		event->clock = parent_event->clock;

8846
	if (!overflow_handler && parent_event) {
8847
		overflow_handler = parent_event->overflow_handler;
8848 8849
		context = parent_event->overflow_handler_context;
	}
8850

8851 8852 8853
	if (overflow_handler) {
		event->overflow_handler	= overflow_handler;
		event->overflow_handler_context = context;
8854 8855 8856
	} else if (is_write_backward(event)){
		event->overflow_handler = perf_event_output_backward;
		event->overflow_handler_context = NULL;
8857
	} else {
8858
		event->overflow_handler = perf_event_output_forward;
8859 8860
		event->overflow_handler_context = NULL;
	}
8861

J
Jiri Olsa 已提交
8862
	perf_event__state_init(event);
8863

8864
	pmu = NULL;
8865

8866
	hwc = &event->hw;
8867
	hwc->sample_period = attr->sample_period;
8868
	if (attr->freq && attr->sample_freq)
8869
		hwc->sample_period = 1;
8870
	hwc->last_period = hwc->sample_period;
8871

8872
	local64_set(&hwc->period_left, hwc->sample_period);
8873

8874
	/*
8875
	 * we currently do not support PERF_FORMAT_GROUP on inherited events
8876
	 */
8877
	if (attr->inherit && (attr->read_format & PERF_FORMAT_GROUP))
8878
		goto err_ns;
8879 8880 8881

	if (!has_branch_stack(event))
		event->attr.branch_sample_type = 0;
8882

8883 8884 8885 8886 8887 8888
	if (cgroup_fd != -1) {
		err = perf_cgroup_connect(cgroup_fd, event, attr, group_leader);
		if (err)
			goto err_ns;
	}

8889
	pmu = perf_init_event(event);
8890
	if (!pmu)
8891 8892
		goto err_ns;
	else if (IS_ERR(pmu)) {
8893
		err = PTR_ERR(pmu);
8894
		goto err_ns;
I
Ingo Molnar 已提交
8895
	}
8896

8897 8898 8899 8900
	err = exclusive_event_init(event);
	if (err)
		goto err_pmu;

8901 8902 8903 8904 8905 8906 8907 8908 8909 8910 8911
	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;
	}

8912
	if (!event->parent) {
8913
		if (event->attr.sample_type & PERF_SAMPLE_CALLCHAIN) {
8914
			err = get_callchain_buffers(attr->sample_max_stack);
8915
			if (err)
8916
				goto err_addr_filters;
8917
		}
8918
	}
8919

8920 8921 8922
	/* symmetric to unaccount_event() in _free_event() */
	account_event(event);

8923
	return event;
8924

8925 8926 8927
err_addr_filters:
	kfree(event->addr_filters_offs);

8928 8929 8930
err_per_task:
	exclusive_event_destroy(event);

8931 8932 8933
err_pmu:
	if (event->destroy)
		event->destroy(event);
8934
	module_put(pmu->module);
8935
err_ns:
8936 8937
	if (is_cgroup_event(event))
		perf_detach_cgroup(event);
8938 8939 8940 8941 8942
	if (event->ns)
		put_pid_ns(event->ns);
	kfree(event);

	return ERR_PTR(err);
T
Thomas Gleixner 已提交
8943 8944
}

8945 8946
static int perf_copy_attr(struct perf_event_attr __user *uattr,
			  struct perf_event_attr *attr)
8947 8948
{
	u32 size;
8949
	int ret;
8950 8951 8952 8953 8954 8955 8956 8957 8958 8959 8960 8961 8962 8963 8964 8965 8966 8967 8968 8969 8970 8971 8972 8973

	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,
8974 8975 8976
	 * 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.
8977 8978
	 */
	if (size > sizeof(*attr)) {
8979 8980 8981
		unsigned char __user *addr;
		unsigned char __user *end;
		unsigned char val;
8982

8983 8984
		addr = (void __user *)uattr + sizeof(*attr);
		end  = (void __user *)uattr + size;
8985

8986
		for (; addr < end; addr++) {
8987 8988 8989 8990 8991 8992
			ret = get_user(val, addr);
			if (ret)
				return ret;
			if (val)
				goto err_size;
		}
8993
		size = sizeof(*attr);
8994 8995 8996 8997 8998 8999
	}

	ret = copy_from_user(attr, uattr, size);
	if (ret)
		return -EFAULT;

9000
	if (attr->__reserved_1)
9001 9002 9003 9004 9005 9006 9007 9008
		return -EINVAL;

	if (attr->sample_type & ~(PERF_SAMPLE_MAX-1))
		return -EINVAL;

	if (attr->read_format & ~(PERF_FORMAT_MAX-1))
		return -EINVAL;

9009 9010 9011 9012 9013 9014 9015 9016 9017 9018 9019 9020 9021 9022 9023 9024 9025 9026 9027 9028 9029 9030 9031 9032 9033 9034 9035 9036
	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;
		}
9037 9038
		/* privileged levels capture (kernel, hv): check permissions */
		if ((mask & PERF_SAMPLE_BRANCH_PERM_PLM)
9039 9040
		    && perf_paranoid_kernel() && !capable(CAP_SYS_ADMIN))
			return -EACCES;
9041
	}
9042

9043
	if (attr->sample_type & PERF_SAMPLE_REGS_USER) {
9044
		ret = perf_reg_validate(attr->sample_regs_user);
9045 9046 9047 9048 9049 9050 9051 9052 9053 9054 9055 9056 9057 9058 9059 9060 9061 9062
		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;
	}
9063

9064 9065
	if (attr->sample_type & PERF_SAMPLE_REGS_INTR)
		ret = perf_reg_validate(attr->sample_regs_intr);
9066 9067 9068 9069 9070 9071 9072 9073 9074
out:
	return ret;

err_size:
	put_user(sizeof(*attr), &uattr->size);
	ret = -E2BIG;
	goto out;
}

9075 9076
static int
perf_event_set_output(struct perf_event *event, struct perf_event *output_event)
9077
{
9078
	struct ring_buffer *rb = NULL;
9079 9080
	int ret = -EINVAL;

9081
	if (!output_event)
9082 9083
		goto set;

9084 9085
	/* don't allow circular references */
	if (event == output_event)
9086 9087
		goto out;

9088 9089 9090 9091 9092 9093 9094
	/*
	 * Don't allow cross-cpu buffers
	 */
	if (output_event->cpu != event->cpu)
		goto out;

	/*
9095
	 * If its not a per-cpu rb, it must be the same task.
9096 9097 9098 9099
	 */
	if (output_event->cpu == -1 && output_event->ctx != event->ctx)
		goto out;

9100 9101 9102 9103 9104 9105
	/*
	 * Mixing clocks in the same buffer is trouble you don't need.
	 */
	if (output_event->clock != event->clock)
		goto out;

9106 9107 9108 9109 9110 9111 9112
	/*
	 * 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;

9113 9114 9115 9116 9117 9118 9119
	/*
	 * 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;

9120
set:
9121
	mutex_lock(&event->mmap_mutex);
9122 9123 9124
	/* Can't redirect output if we've got an active mmap() */
	if (atomic_read(&event->mmap_count))
		goto unlock;
9125

9126
	if (output_event) {
9127 9128 9129
		/* get the rb we want to redirect to */
		rb = ring_buffer_get(output_event);
		if (!rb)
9130
			goto unlock;
9131 9132
	}

9133
	ring_buffer_attach(event, rb);
9134

9135
	ret = 0;
9136 9137 9138
unlock:
	mutex_unlock(&event->mmap_mutex);

9139 9140 9141 9142
out:
	return ret;
}

P
Peter Zijlstra 已提交
9143 9144 9145 9146 9147 9148 9149 9150 9151
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);
}

9152 9153 9154 9155 9156 9157 9158 9159 9160 9161 9162 9163 9164 9165 9166 9167 9168 9169 9170 9171 9172 9173 9174 9175 9176 9177 9178 9179 9180 9181 9182 9183 9184 9185 9186 9187 9188
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
9189
/**
9190
 * sys_perf_event_open - open a performance event, associate it to a task/cpu
I
Ingo Molnar 已提交
9191
 *
9192
 * @attr_uptr:	event_id type attributes for monitoring/sampling
T
Thomas Gleixner 已提交
9193
 * @pid:		target pid
I
Ingo Molnar 已提交
9194
 * @cpu:		target cpu
9195
 * @group_fd:		group leader event fd
T
Thomas Gleixner 已提交
9196
 */
9197 9198
SYSCALL_DEFINE5(perf_event_open,
		struct perf_event_attr __user *, attr_uptr,
9199
		pid_t, pid, int, cpu, int, group_fd, unsigned long, flags)
T
Thomas Gleixner 已提交
9200
{
9201 9202
	struct perf_event *group_leader = NULL, *output_event = NULL;
	struct perf_event *event, *sibling;
9203
	struct perf_event_attr attr;
P
Peter Zijlstra 已提交
9204
	struct perf_event_context *ctx, *uninitialized_var(gctx);
9205
	struct file *event_file = NULL;
9206
	struct fd group = {NULL, 0};
M
Matt Helsley 已提交
9207
	struct task_struct *task = NULL;
9208
	struct pmu *pmu;
9209
	int event_fd;
9210
	int move_group = 0;
9211
	int err;
9212
	int f_flags = O_RDWR;
9213
	int cgroup_fd = -1;
T
Thomas Gleixner 已提交
9214

9215
	/* for future expandability... */
S
Stephane Eranian 已提交
9216
	if (flags & ~PERF_FLAG_ALL)
9217 9218
		return -EINVAL;

9219 9220 9221
	err = perf_copy_attr(attr_uptr, &attr);
	if (err)
		return err;
9222

9223 9224 9225 9226 9227
	if (!attr.exclude_kernel) {
		if (perf_paranoid_kernel() && !capable(CAP_SYS_ADMIN))
			return -EACCES;
	}

9228
	if (attr.freq) {
9229
		if (attr.sample_freq > sysctl_perf_event_sample_rate)
9230
			return -EINVAL;
9231 9232 9233
	} else {
		if (attr.sample_period & (1ULL << 63))
			return -EINVAL;
9234 9235
	}

9236 9237 9238
	if (!attr.sample_max_stack)
		attr.sample_max_stack = sysctl_perf_event_max_stack;

S
Stephane Eranian 已提交
9239 9240 9241 9242 9243 9244 9245 9246 9247
	/*
	 * 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;

9248 9249 9250 9251
	if (flags & PERF_FLAG_FD_CLOEXEC)
		f_flags |= O_CLOEXEC;

	event_fd = get_unused_fd_flags(f_flags);
9252 9253 9254
	if (event_fd < 0)
		return event_fd;

9255
	if (group_fd != -1) {
9256 9257
		err = perf_fget_light(group_fd, &group);
		if (err)
9258
			goto err_fd;
9259
		group_leader = group.file->private_data;
9260 9261 9262 9263 9264 9265
		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
9266
	if (pid != -1 && !(flags & PERF_FLAG_PID_CGROUP)) {
9267 9268 9269 9270 9271 9272 9273
		task = find_lively_task_by_vpid(pid);
		if (IS_ERR(task)) {
			err = PTR_ERR(task);
			goto err_group_fd;
		}
	}

9274 9275 9276 9277 9278 9279
	if (task && group_leader &&
	    group_leader->attr.inherit != attr.inherit) {
		err = -EINVAL;
		goto err_task;
	}

9280 9281
	get_online_cpus();

9282 9283 9284 9285 9286 9287 9288 9289 9290 9291 9292 9293 9294 9295 9296 9297 9298 9299
	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;
	}

9300 9301 9302
	if (flags & PERF_FLAG_PID_CGROUP)
		cgroup_fd = pid;

9303
	event = perf_event_alloc(&attr, cpu, task, group_leader, NULL,
9304
				 NULL, NULL, cgroup_fd);
9305 9306
	if (IS_ERR(event)) {
		err = PTR_ERR(event);
9307
		goto err_cred;
9308 9309
	}

9310 9311
	if (is_sampling_event(event)) {
		if (event->pmu->capabilities & PERF_PMU_CAP_NO_INTERRUPT) {
9312
			err = -EOPNOTSUPP;
9313 9314 9315 9316
			goto err_alloc;
		}
	}

9317 9318 9319 9320 9321
	/*
	 * Special case software events and allow them to be part of
	 * any hardware group.
	 */
	pmu = event->pmu;
9322

9323 9324 9325 9326 9327 9328
	if (attr.use_clockid) {
		err = perf_event_set_clock(event, attr.clockid);
		if (err)
			goto err_alloc;
	}

9329 9330 9331 9332 9333 9334 9335 9336 9337 9338 9339 9340 9341 9342 9343 9344 9345 9346 9347 9348 9349 9350
	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;
		}
	}
9351 9352 9353 9354

	/*
	 * Get the target context (task or percpu):
	 */
9355
	ctx = find_get_context(pmu, task, event);
9356 9357
	if (IS_ERR(ctx)) {
		err = PTR_ERR(ctx);
9358
		goto err_alloc;
9359 9360
	}

9361 9362 9363 9364 9365
	if ((pmu->capabilities & PERF_PMU_CAP_EXCLUSIVE) && group_leader) {
		err = -EBUSY;
		goto err_context;
	}

I
Ingo Molnar 已提交
9366
	/*
9367
	 * Look up the group leader (we will attach this event to it):
9368
	 */
9369
	if (group_leader) {
9370
		err = -EINVAL;
9371 9372

		/*
I
Ingo Molnar 已提交
9373 9374 9375 9376
		 * Do not allow a recursive hierarchy (this new sibling
		 * becoming part of another group-sibling):
		 */
		if (group_leader->group_leader != group_leader)
9377
			goto err_context;
9378 9379 9380 9381 9382

		/* 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
9383 9384 9385
		/*
		 * Do not allow to attach to a group in a different
		 * task or CPU context:
9386
		 */
9387
		if (move_group) {
9388 9389 9390 9391 9392 9393 9394 9395 9396 9397 9398 9399 9400
			/*
			 * 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)
9401 9402 9403 9404 9405 9406
				goto err_context;
		} else {
			if (group_leader->ctx != ctx)
				goto err_context;
		}

9407 9408 9409
		/*
		 * Only a group leader can be exclusive or pinned
		 */
9410
		if (attr.exclusive || attr.pinned)
9411
			goto err_context;
9412 9413 9414 9415 9416
	}

	if (output_event) {
		err = perf_event_set_output(event, output_event);
		if (err)
9417
			goto err_context;
9418
	}
T
Thomas Gleixner 已提交
9419

9420 9421
	event_file = anon_inode_getfile("[perf_event]", &perf_fops, event,
					f_flags);
9422 9423
	if (IS_ERR(event_file)) {
		err = PTR_ERR(event_file);
9424
		event_file = NULL;
9425
		goto err_context;
9426
	}
9427

9428
	if (move_group) {
P
Peter Zijlstra 已提交
9429
		gctx = group_leader->ctx;
9430
		mutex_lock_double(&gctx->mutex, &ctx->mutex);
9431 9432 9433 9434
		if (gctx->task == TASK_TOMBSTONE) {
			err = -ESRCH;
			goto err_locked;
		}
9435 9436 9437 9438
	} else {
		mutex_lock(&ctx->mutex);
	}

9439 9440 9441 9442 9443
	if (ctx->task == TASK_TOMBSTONE) {
		err = -ESRCH;
		goto err_locked;
	}

P
Peter Zijlstra 已提交
9444 9445 9446 9447 9448
	if (!perf_event_validate_size(event)) {
		err = -E2BIG;
		goto err_locked;
	}

9449 9450 9451 9452 9453 9454 9455
	/*
	 * 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
9456

9457 9458 9459
		err = -EBUSY;
		goto err_locked;
	}
P
Peter Zijlstra 已提交
9460

9461 9462
	WARN_ON_ONCE(ctx->parent_ctx);

9463 9464 9465 9466 9467
	/*
	 * This is the point on no return; we cannot fail hereafter. This is
	 * where we start modifying current state.
	 */

9468
	if (move_group) {
P
Peter Zijlstra 已提交
9469 9470 9471 9472
		/*
		 * See perf_event_ctx_lock() for comments on the details
		 * of swizzling perf_event::ctx.
		 */
9473
		perf_remove_from_context(group_leader, 0);
J
Jiri Olsa 已提交
9474

9475 9476
		list_for_each_entry(sibling, &group_leader->sibling_list,
				    group_entry) {
9477
			perf_remove_from_context(sibling, 0);
9478 9479 9480
			put_ctx(gctx);
		}

P
Peter Zijlstra 已提交
9481 9482 9483 9484
		/*
		 * Wait for everybody to stop referencing the events through
		 * the old lists, before installing it on new lists.
		 */
9485
		synchronize_rcu();
P
Peter Zijlstra 已提交
9486

9487 9488 9489 9490 9491 9492 9493 9494 9495 9496
		/*
		 * 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.
		 */
9497 9498
		list_for_each_entry(sibling, &group_leader->sibling_list,
				    group_entry) {
9499
			perf_event__state_init(sibling);
9500
			perf_install_in_context(ctx, sibling, sibling->cpu);
9501 9502
			get_ctx(ctx);
		}
9503 9504 9505 9506 9507 9508 9509 9510 9511

		/*
		 * 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);
9512

9513 9514 9515 9516 9517 9518
		/*
		 * Now that all events are installed in @ctx, nothing
		 * references @gctx anymore, so drop the last reference we have
		 * on it.
		 */
		put_ctx(gctx);
9519 9520
	}

9521 9522 9523 9524 9525 9526 9527 9528 9529
	/*
	 * 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
9530 9531
	event->owner = current;

9532
	perf_install_in_context(ctx, event, event->cpu);
9533
	perf_unpin_context(ctx);
P
Peter Zijlstra 已提交
9534

9535
	if (move_group)
P
Peter Zijlstra 已提交
9536
		mutex_unlock(&gctx->mutex);
9537
	mutex_unlock(&ctx->mutex);
9538

9539 9540 9541 9542 9543
	if (task) {
		mutex_unlock(&task->signal->cred_guard_mutex);
		put_task_struct(task);
	}

9544 9545
	put_online_cpus();

9546 9547 9548
	mutex_lock(&current->perf_event_mutex);
	list_add_tail(&event->owner_entry, &current->perf_event_list);
	mutex_unlock(&current->perf_event_mutex);
9549

9550 9551 9552 9553 9554 9555
	/*
	 * 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().
	 */
9556
	fdput(group);
9557 9558
	fd_install(event_fd, event_file);
	return event_fd;
T
Thomas Gleixner 已提交
9559

9560 9561 9562 9563 9564 9565
err_locked:
	if (move_group)
		mutex_unlock(&gctx->mutex);
	mutex_unlock(&ctx->mutex);
/* err_file: */
	fput(event_file);
9566
err_context:
9567
	perf_unpin_context(ctx);
9568
	put_ctx(ctx);
9569
err_alloc:
P
Peter Zijlstra 已提交
9570 9571 9572 9573 9574 9575
	/*
	 * 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);
9576 9577 9578
err_cred:
	if (task)
		mutex_unlock(&task->signal->cred_guard_mutex);
9579
err_cpus:
9580
	put_online_cpus();
9581
err_task:
P
Peter Zijlstra 已提交
9582 9583
	if (task)
		put_task_struct(task);
9584
err_group_fd:
9585
	fdput(group);
9586 9587
err_fd:
	put_unused_fd(event_fd);
9588
	return err;
T
Thomas Gleixner 已提交
9589 9590
}

9591 9592 9593 9594 9595
/**
 * 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
9596
 * @task: task to profile (NULL for percpu)
9597 9598 9599
 */
struct perf_event *
perf_event_create_kernel_counter(struct perf_event_attr *attr, int cpu,
M
Matt Helsley 已提交
9600
				 struct task_struct *task,
9601 9602
				 perf_overflow_handler_t overflow_handler,
				 void *context)
9603 9604
{
	struct perf_event_context *ctx;
9605
	struct perf_event *event;
9606
	int err;
9607

9608 9609 9610
	/*
	 * Get the target context (task or percpu):
	 */
9611

9612
	event = perf_event_alloc(attr, cpu, task, NULL, NULL,
9613
				 overflow_handler, context, -1);
9614 9615 9616 9617
	if (IS_ERR(event)) {
		err = PTR_ERR(event);
		goto err;
	}
9618

9619
	/* Mark owner so we could distinguish it from user events. */
9620
	event->owner = TASK_TOMBSTONE;
9621

9622
	ctx = find_get_context(event->pmu, task, event);
9623 9624
	if (IS_ERR(ctx)) {
		err = PTR_ERR(ctx);
9625
		goto err_free;
9626
	}
9627 9628 9629

	WARN_ON_ONCE(ctx->parent_ctx);
	mutex_lock(&ctx->mutex);
9630 9631 9632 9633 9634
	if (ctx->task == TASK_TOMBSTONE) {
		err = -ESRCH;
		goto err_unlock;
	}

9635 9636
	if (!exclusive_event_installable(event, ctx)) {
		err = -EBUSY;
9637
		goto err_unlock;
9638 9639
	}

9640
	perf_install_in_context(ctx, event, cpu);
9641
	perf_unpin_context(ctx);
9642 9643 9644 9645
	mutex_unlock(&ctx->mutex);

	return event;

9646 9647 9648 9649
err_unlock:
	mutex_unlock(&ctx->mutex);
	perf_unpin_context(ctx);
	put_ctx(ctx);
9650 9651 9652
err_free:
	free_event(event);
err:
9653
	return ERR_PTR(err);
9654
}
9655
EXPORT_SYMBOL_GPL(perf_event_create_kernel_counter);
9656

9657 9658 9659 9660 9661 9662 9663 9664 9665 9666
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
9667 9668 9669 9670 9671
	/*
	 * See perf_event_ctx_lock() for comments on the details
	 * of swizzling perf_event::ctx.
	 */
	mutex_lock_double(&src_ctx->mutex, &dst_ctx->mutex);
9672 9673
	list_for_each_entry_safe(event, tmp, &src_ctx->event_list,
				 event_entry) {
9674
		perf_remove_from_context(event, 0);
9675
		unaccount_event_cpu(event, src_cpu);
9676
		put_ctx(src_ctx);
9677
		list_add(&event->migrate_entry, &events);
9678 9679
	}

9680 9681 9682
	/*
	 * Wait for the events to quiesce before re-instating them.
	 */
9683 9684
	synchronize_rcu();

9685 9686 9687 9688 9689 9690 9691 9692 9693 9694 9695 9696 9697 9698 9699 9700 9701 9702 9703 9704 9705 9706 9707 9708
	/*
	 * 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.
	 */
9709 9710
	list_for_each_entry_safe(event, tmp, &events, migrate_entry) {
		list_del(&event->migrate_entry);
9711 9712
		if (event->state >= PERF_EVENT_STATE_OFF)
			event->state = PERF_EVENT_STATE_INACTIVE;
9713
		account_event_cpu(event, dst_cpu);
9714 9715 9716 9717
		perf_install_in_context(dst_ctx, event, dst_cpu);
		get_ctx(dst_ctx);
	}
	mutex_unlock(&dst_ctx->mutex);
P
Peter Zijlstra 已提交
9718
	mutex_unlock(&src_ctx->mutex);
9719 9720 9721
}
EXPORT_SYMBOL_GPL(perf_pmu_migrate_context);

9722
static void sync_child_event(struct perf_event *child_event,
9723
			       struct task_struct *child)
9724
{
9725
	struct perf_event *parent_event = child_event->parent;
9726
	u64 child_val;
9727

9728 9729
	if (child_event->attr.inherit_stat)
		perf_event_read_event(child_event, child);
9730

P
Peter Zijlstra 已提交
9731
	child_val = perf_event_count(child_event);
9732 9733 9734 9735

	/*
	 * Add back the child's count to the parent's count:
	 */
9736
	atomic64_add(child_val, &parent_event->child_count);
9737 9738 9739 9740
	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);
9741 9742
}

9743
static void
9744 9745 9746
perf_event_exit_event(struct perf_event *child_event,
		      struct perf_event_context *child_ctx,
		      struct task_struct *child)
9747
{
9748 9749
	struct perf_event *parent_event = child_event->parent;

9750 9751 9752 9753 9754 9755 9756 9757 9758 9759 9760 9761
	/*
	 * 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.
	 */
9762 9763 9764
	raw_spin_lock_irq(&child_ctx->lock);
	WARN_ON_ONCE(child_ctx->is_active);

9765
	if (parent_event)
9766 9767
		perf_group_detach(child_event);
	list_del_event(child_event, child_ctx);
P
Peter Zijlstra 已提交
9768
	child_event->state = PERF_EVENT_STATE_EXIT; /* is_event_hup() */
9769
	raw_spin_unlock_irq(&child_ctx->lock);
9770

9771
	/*
9772
	 * Parent events are governed by their filedesc, retain them.
9773
	 */
9774
	if (!parent_event) {
9775
		perf_event_wakeup(child_event);
9776
		return;
9777
	}
9778 9779 9780 9781 9782 9783 9784 9785 9786 9787 9788 9789 9790 9791 9792 9793 9794 9795 9796 9797
	/*
	 * 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);
9798 9799
}

P
Peter Zijlstra 已提交
9800
static void perf_event_exit_task_context(struct task_struct *child, int ctxn)
9801
{
9802
	struct perf_event_context *child_ctx, *clone_ctx = NULL;
9803 9804 9805
	struct perf_event *child_event, *next;

	WARN_ON_ONCE(child != current);
9806

9807
	child_ctx = perf_pin_task_context(child, ctxn);
9808
	if (!child_ctx)
9809 9810
		return;

9811
	/*
9812 9813 9814 9815 9816 9817 9818 9819
	 * 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().
9820
	 */
9821
	mutex_lock(&child_ctx->mutex);
9822 9823

	/*
9824 9825 9826
	 * 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.
9827
	 */
9828
	raw_spin_lock_irq(&child_ctx->lock);
9829
	task_ctx_sched_out(__get_cpu_context(child_ctx), child_ctx);
9830

9831
	/*
9832 9833
	 * Now that the context is inactive, destroy the task <-> ctx relation
	 * and mark the context dead.
9834
	 */
9835 9836 9837 9838
	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 */
9839

9840
	clone_ctx = unclone_ctx(child_ctx);
9841
	raw_spin_unlock_irq(&child_ctx->lock);
P
Peter Zijlstra 已提交
9842

9843 9844
	if (clone_ctx)
		put_ctx(clone_ctx);
9845

P
Peter Zijlstra 已提交
9846
	/*
9847 9848 9849
	 * 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
9850
	 */
9851
	perf_event_task(child, child_ctx, 0);
9852

9853
	list_for_each_entry_safe(child_event, next, &child_ctx->event_list, event_entry)
9854
		perf_event_exit_event(child_event, child_ctx, child);
9855

9856 9857 9858
	mutex_unlock(&child_ctx->mutex);

	put_ctx(child_ctx);
9859 9860
}

P
Peter Zijlstra 已提交
9861 9862
/*
 * When a child task exits, feed back event values to parent events.
9863 9864 9865
 *
 * Can be called with cred_guard_mutex held when called from
 * install_exec_creds().
P
Peter Zijlstra 已提交
9866 9867 9868
 */
void perf_event_exit_task(struct task_struct *child)
{
P
Peter Zijlstra 已提交
9869
	struct perf_event *event, *tmp;
P
Peter Zijlstra 已提交
9870 9871
	int ctxn;

P
Peter Zijlstra 已提交
9872 9873 9874 9875 9876 9877 9878 9879 9880 9881
	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.
		 */
9882
		smp_store_release(&event->owner, NULL);
P
Peter Zijlstra 已提交
9883 9884 9885
	}
	mutex_unlock(&child->perf_event_mutex);

P
Peter Zijlstra 已提交
9886 9887
	for_each_task_context_nr(ctxn)
		perf_event_exit_task_context(child, ctxn);
J
Jiri Olsa 已提交
9888 9889 9890 9891 9892 9893 9894 9895

	/*
	 * 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
9896 9897
}

9898 9899 9900 9901 9902 9903 9904 9905 9906 9907 9908 9909
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);

9910
	put_event(parent);
9911

P
Peter Zijlstra 已提交
9912
	raw_spin_lock_irq(&ctx->lock);
9913
	perf_group_detach(event);
9914
	list_del_event(event, ctx);
P
Peter Zijlstra 已提交
9915
	raw_spin_unlock_irq(&ctx->lock);
9916 9917 9918
	free_event(event);
}

9919
/*
P
Peter Zijlstra 已提交
9920
 * Free an unexposed, unused context as created by inheritance by
P
Peter Zijlstra 已提交
9921
 * perf_event_init_task below, used by fork() in case of fail.
P
Peter Zijlstra 已提交
9922 9923 9924
 *
 * Not all locks are strictly required, but take them anyway to be nice and
 * help out with the lockdep assertions.
9925
 */
9926
void perf_event_free_task(struct task_struct *task)
9927
{
P
Peter Zijlstra 已提交
9928
	struct perf_event_context *ctx;
9929
	struct perf_event *event, *tmp;
P
Peter Zijlstra 已提交
9930
	int ctxn;
9931

P
Peter Zijlstra 已提交
9932 9933 9934 9935
	for_each_task_context_nr(ctxn) {
		ctx = task->perf_event_ctxp[ctxn];
		if (!ctx)
			continue;
9936

P
Peter Zijlstra 已提交
9937
		mutex_lock(&ctx->mutex);
9938
again:
P
Peter Zijlstra 已提交
9939 9940 9941
		list_for_each_entry_safe(event, tmp, &ctx->pinned_groups,
				group_entry)
			perf_free_event(event, ctx);
9942

P
Peter Zijlstra 已提交
9943 9944 9945
		list_for_each_entry_safe(event, tmp, &ctx->flexible_groups,
				group_entry)
			perf_free_event(event, ctx);
9946

P
Peter Zijlstra 已提交
9947 9948 9949
		if (!list_empty(&ctx->pinned_groups) ||
				!list_empty(&ctx->flexible_groups))
			goto again;
9950

P
Peter Zijlstra 已提交
9951
		mutex_unlock(&ctx->mutex);
9952

P
Peter Zijlstra 已提交
9953 9954
		put_ctx(ctx);
	}
9955 9956
}

9957 9958 9959 9960 9961 9962 9963 9964
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]);
}

9965
struct file *perf_event_get(unsigned int fd)
9966
{
9967
	struct file *file;
9968

9969 9970 9971
	file = fget_raw(fd);
	if (!file)
		return ERR_PTR(-EBADF);
9972

9973 9974 9975 9976
	if (file->f_op != &perf_fops) {
		fput(file);
		return ERR_PTR(-EBADF);
	}
9977

9978
	return file;
9979 9980 9981 9982 9983 9984 9985 9986 9987 9988
}

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
9989 9990 9991 9992 9993 9994 9995 9996 9997 9998 9999
/*
 * 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)
{
10000
	enum perf_event_active_state parent_state = parent_event->state;
P
Peter Zijlstra 已提交
10001
	struct perf_event *child_event;
10002
	unsigned long flags;
P
Peter Zijlstra 已提交
10003 10004 10005 10006 10007 10008 10009 10010 10011 10012 10013 10014

	/*
	 * 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,
10015
					   child,
P
Peter Zijlstra 已提交
10016
					   group_leader, parent_event,
10017
					   NULL, NULL, -1);
P
Peter Zijlstra 已提交
10018 10019
	if (IS_ERR(child_event))
		return child_event;
10020

10021 10022 10023 10024 10025 10026 10027
	/*
	 * 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);
10028 10029
	if (is_orphaned_event(parent_event) ||
	    !atomic_long_inc_not_zero(&parent_event->refcount)) {
10030
		mutex_unlock(&parent_event->child_mutex);
10031 10032 10033 10034
		free_event(child_event);
		return NULL;
	}

P
Peter Zijlstra 已提交
10035 10036 10037 10038 10039 10040 10041
	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.
	 */
10042
	if (parent_state >= PERF_EVENT_STATE_INACTIVE)
P
Peter Zijlstra 已提交
10043 10044 10045 10046 10047 10048 10049 10050 10051 10052 10053 10054 10055 10056 10057 10058
		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;
10059 10060
	child_event->overflow_handler_context
		= parent_event->overflow_handler_context;
P
Peter Zijlstra 已提交
10061

10062 10063 10064 10065
	/*
	 * Precalculate sample_data sizes
	 */
	perf_event__header_size(child_event);
10066
	perf_event__id_header_size(child_event);
10067

P
Peter Zijlstra 已提交
10068 10069 10070
	/*
	 * Link it up in the child's context:
	 */
10071
	raw_spin_lock_irqsave(&child_ctx->lock, flags);
P
Peter Zijlstra 已提交
10072
	add_event_to_ctx(child_event, child_ctx);
10073
	raw_spin_unlock_irqrestore(&child_ctx->lock, flags);
P
Peter Zijlstra 已提交
10074 10075 10076 10077 10078 10079 10080 10081 10082 10083 10084 10085 10086 10087 10088 10089 10090 10091 10092 10093 10094 10095 10096 10097 10098 10099 10100 10101 10102 10103 10104

	/*
	 * 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;
10105 10106 10107 10108 10109
}

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
10110
		   struct task_struct *child, int ctxn,
10111 10112 10113
		   int *inherited_all)
{
	int ret;
P
Peter Zijlstra 已提交
10114
	struct perf_event_context *child_ctx;
10115 10116 10117 10118

	if (!event->attr.inherit) {
		*inherited_all = 0;
		return 0;
10119 10120
	}

10121
	child_ctx = child->perf_event_ctxp[ctxn];
10122 10123 10124 10125 10126 10127 10128
	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.
		 */
10129

10130
		child_ctx = alloc_perf_context(parent_ctx->pmu, child);
10131 10132
		if (!child_ctx)
			return -ENOMEM;
10133

P
Peter Zijlstra 已提交
10134
		child->perf_event_ctxp[ctxn] = child_ctx;
10135 10136 10137 10138 10139 10140 10141 10142 10143
	}

	ret = inherit_group(event, parent, parent_ctx,
			    child, child_ctx);

	if (ret)
		*inherited_all = 0;

	return ret;
10144 10145
}

10146
/*
10147
 * Initialize the perf_event context in task_struct
10148
 */
10149
static int perf_event_init_context(struct task_struct *child, int ctxn)
10150
{
10151
	struct perf_event_context *child_ctx, *parent_ctx;
10152 10153
	struct perf_event_context *cloned_ctx;
	struct perf_event *event;
10154
	struct task_struct *parent = current;
10155
	int inherited_all = 1;
10156
	unsigned long flags;
10157
	int ret = 0;
10158

P
Peter Zijlstra 已提交
10159
	if (likely(!parent->perf_event_ctxp[ctxn]))
10160 10161
		return 0;

10162
	/*
10163 10164
	 * If the parent's context is a clone, pin it so it won't get
	 * swapped under us.
10165
	 */
P
Peter Zijlstra 已提交
10166
	parent_ctx = perf_pin_task_context(parent, ctxn);
10167 10168
	if (!parent_ctx)
		return 0;
10169

10170 10171 10172 10173 10174 10175 10176
	/*
	 * 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.
	 */

10177 10178 10179 10180
	/*
	 * Lock the parent list. No need to lock the child - not PID
	 * hashed yet and not running, so nobody can access it.
	 */
10181
	mutex_lock(&parent_ctx->mutex);
10182 10183 10184 10185 10186

	/*
	 * We dont have to disable NMIs - we are only looking at
	 * the list, not manipulating it:
	 */
10187
	list_for_each_entry(event, &parent_ctx->pinned_groups, group_entry) {
P
Peter Zijlstra 已提交
10188 10189
		ret = inherit_task_group(event, parent, parent_ctx,
					 child, ctxn, &inherited_all);
10190 10191 10192
		if (ret)
			break;
	}
10193

10194 10195 10196 10197 10198 10199 10200 10201 10202
	/*
	 * 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);

10203
	list_for_each_entry(event, &parent_ctx->flexible_groups, group_entry) {
P
Peter Zijlstra 已提交
10204 10205
		ret = inherit_task_group(event, parent, parent_ctx,
					 child, ctxn, &inherited_all);
10206
		if (ret)
10207
			break;
10208 10209
	}

10210 10211 10212
	raw_spin_lock_irqsave(&parent_ctx->lock, flags);
	parent_ctx->rotate_disable = 0;

P
Peter Zijlstra 已提交
10213
	child_ctx = child->perf_event_ctxp[ctxn];
10214

10215
	if (child_ctx && inherited_all) {
10216 10217 10218
		/*
		 * 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
10219 10220 10221
		 *
		 * Note that if the parent is a clone, the holding of
		 * parent_ctx->lock avoids it from being uncloned.
10222
		 */
P
Peter Zijlstra 已提交
10223
		cloned_ctx = parent_ctx->parent_ctx;
10224 10225
		if (cloned_ctx) {
			child_ctx->parent_ctx = cloned_ctx;
10226
			child_ctx->parent_gen = parent_ctx->parent_gen;
10227 10228 10229 10230 10231
		} else {
			child_ctx->parent_ctx = parent_ctx;
			child_ctx->parent_gen = parent_ctx->generation;
		}
		get_ctx(child_ctx->parent_ctx);
10232 10233
	}

P
Peter Zijlstra 已提交
10234
	raw_spin_unlock_irqrestore(&parent_ctx->lock, flags);
10235
	mutex_unlock(&parent_ctx->mutex);
10236

10237
	perf_unpin_context(parent_ctx);
10238
	put_ctx(parent_ctx);
10239

10240
	return ret;
10241 10242
}

P
Peter Zijlstra 已提交
10243 10244 10245 10246 10247 10248 10249
/*
 * Initialize the perf_event context in task_struct
 */
int perf_event_init_task(struct task_struct *child)
{
	int ctxn, ret;

10250 10251 10252 10253
	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
10254 10255
	for_each_task_context_nr(ctxn) {
		ret = perf_event_init_context(child, ctxn);
P
Peter Zijlstra 已提交
10256 10257
		if (ret) {
			perf_event_free_task(child);
P
Peter Zijlstra 已提交
10258
			return ret;
P
Peter Zijlstra 已提交
10259
		}
P
Peter Zijlstra 已提交
10260 10261 10262 10263 10264
	}

	return 0;
}

10265 10266
static void __init perf_event_init_all_cpus(void)
{
10267
	struct swevent_htable *swhash;
10268 10269 10270
	int cpu;

	for_each_possible_cpu(cpu) {
10271 10272
		swhash = &per_cpu(swevent_htable, cpu);
		mutex_init(&swhash->hlist_mutex);
10273
		INIT_LIST_HEAD(&per_cpu(active_ctx_list, cpu));
10274 10275 10276

		INIT_LIST_HEAD(&per_cpu(pmu_sb_events.list, cpu));
		raw_spin_lock_init(&per_cpu(pmu_sb_events.lock, cpu));
10277 10278 10279
	}
}

10280
static void perf_event_init_cpu(int cpu)
T
Thomas Gleixner 已提交
10281
{
P
Peter Zijlstra 已提交
10282
	struct swevent_htable *swhash = &per_cpu(swevent_htable, cpu);
T
Thomas Gleixner 已提交
10283

10284
	mutex_lock(&swhash->hlist_mutex);
10285
	if (swhash->hlist_refcount > 0 && !swevent_hlist_deref(swhash)) {
10286 10287
		struct swevent_hlist *hlist;

10288 10289 10290
		hlist = kzalloc_node(sizeof(*hlist), GFP_KERNEL, cpu_to_node(cpu));
		WARN_ON(!hlist);
		rcu_assign_pointer(swhash->swevent_hlist, hlist);
10291
	}
10292
	mutex_unlock(&swhash->hlist_mutex);
T
Thomas Gleixner 已提交
10293 10294
}

10295
#if defined CONFIG_HOTPLUG_CPU || defined CONFIG_KEXEC_CORE
P
Peter Zijlstra 已提交
10296
static void __perf_event_exit_context(void *__info)
T
Thomas Gleixner 已提交
10297
{
P
Peter Zijlstra 已提交
10298
	struct perf_event_context *ctx = __info;
10299 10300
	struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
	struct perf_event *event;
T
Thomas Gleixner 已提交
10301

10302 10303
	raw_spin_lock(&ctx->lock);
	list_for_each_entry(event, &ctx->event_list, event_entry)
10304
		__perf_remove_from_context(event, cpuctx, ctx, (void *)DETACH_GROUP);
10305
	raw_spin_unlock(&ctx->lock);
T
Thomas Gleixner 已提交
10306
}
P
Peter Zijlstra 已提交
10307 10308 10309 10310 10311 10312 10313 10314 10315

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) {
10316
		ctx = &per_cpu_ptr(pmu->pmu_cpu_context, cpu)->ctx;
P
Peter Zijlstra 已提交
10317 10318 10319 10320 10321 10322 10323 10324

		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);
}

10325
static void perf_event_exit_cpu(int cpu)
T
Thomas Gleixner 已提交
10326
{
P
Peter Zijlstra 已提交
10327
	perf_event_exit_cpu_context(cpu);
T
Thomas Gleixner 已提交
10328 10329
}
#else
10330
static inline void perf_event_exit_cpu(int cpu) { }
T
Thomas Gleixner 已提交
10331 10332
#endif

P
Peter Zijlstra 已提交
10333 10334 10335 10336 10337 10338 10339 10340 10341 10342 10343 10344 10345 10346 10347 10348 10349 10350 10351 10352
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,
};

10353
static int
T
Thomas Gleixner 已提交
10354 10355 10356 10357
perf_cpu_notify(struct notifier_block *self, unsigned long action, void *hcpu)
{
	unsigned int cpu = (long)hcpu;

10358
	switch (action & ~CPU_TASKS_FROZEN) {
T
Thomas Gleixner 已提交
10359 10360

	case CPU_UP_PREPARE:
10361 10362 10363 10364 10365 10366 10367
		/*
		 * This must be done before the CPU comes alive, because the
		 * moment we can run tasks we can encounter (software) events.
		 *
		 * Specifically, someone can have inherited events on kthreadd
		 * or a pre-existing worker thread that gets re-bound.
		 */
10368
		perf_event_init_cpu(cpu);
T
Thomas Gleixner 已提交
10369 10370 10371
		break;

	case CPU_DOWN_PREPARE:
10372 10373 10374 10375 10376 10377 10378 10379 10380 10381 10382 10383
		/*
		 * This must be done before the CPU dies because after that an
		 * active event might want to IPI the CPU and that'll not work
		 * so great for dead CPUs.
		 *
		 * XXX smp_call_function_single() return -ENXIO without a warn
		 * so we could possibly deal with this.
		 *
		 * This is safe against new events arriving because
		 * sys_perf_event_open() serializes against hotplug using
		 * get_online_cpus().
		 */
10384
		perf_event_exit_cpu(cpu);
T
Thomas Gleixner 已提交
10385 10386 10387 10388 10389 10390 10391 10392
		break;
	default:
		break;
	}

	return NOTIFY_OK;
}

10393
void __init perf_event_init(void)
T
Thomas Gleixner 已提交
10394
{
10395 10396
	int ret;

P
Peter Zijlstra 已提交
10397 10398
	idr_init(&pmu_idr);

10399
	perf_event_init_all_cpus();
10400
	init_srcu_struct(&pmus_srcu);
P
Peter Zijlstra 已提交
10401 10402 10403
	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);
10404 10405
	perf_tp_register();
	perf_cpu_notifier(perf_cpu_notify);
P
Peter Zijlstra 已提交
10406
	register_reboot_notifier(&perf_reboot_notifier);
10407 10408 10409

	ret = init_hw_breakpoint();
	WARN(ret, "hw_breakpoint initialization failed with: %d", ret);
10410

10411 10412 10413 10414 10415 10416
	/*
	 * 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
10417
}
P
Peter Zijlstra 已提交
10418

10419 10420 10421 10422 10423 10424 10425 10426 10427 10428 10429
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;
}
10430
EXPORT_SYMBOL_GPL(perf_event_sysfs_show);
10431

P
Peter Zijlstra 已提交
10432 10433 10434 10435 10436 10437 10438 10439 10440 10441 10442 10443 10444 10445 10446 10447 10448 10449 10450 10451 10452 10453 10454 10455 10456 10457 10458
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
10459 10460

#ifdef CONFIG_CGROUP_PERF
10461 10462
static struct cgroup_subsys_state *
perf_cgroup_css_alloc(struct cgroup_subsys_state *parent_css)
S
Stephane Eranian 已提交
10463 10464 10465
{
	struct perf_cgroup *jc;

10466
	jc = kzalloc(sizeof(*jc), GFP_KERNEL);
S
Stephane Eranian 已提交
10467 10468 10469 10470 10471 10472 10473 10474 10475 10476 10477 10478
	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;
}

10479
static void perf_cgroup_css_free(struct cgroup_subsys_state *css)
S
Stephane Eranian 已提交
10480
{
10481 10482
	struct perf_cgroup *jc = container_of(css, struct perf_cgroup, css);

S
Stephane Eranian 已提交
10483 10484 10485 10486 10487 10488 10489
	free_percpu(jc->info);
	kfree(jc);
}

static int __perf_cgroup_move(void *info)
{
	struct task_struct *task = info;
10490
	rcu_read_lock();
S
Stephane Eranian 已提交
10491
	perf_cgroup_switch(task, PERF_CGROUP_SWOUT | PERF_CGROUP_SWIN);
10492
	rcu_read_unlock();
S
Stephane Eranian 已提交
10493 10494 10495
	return 0;
}

10496
static void perf_cgroup_attach(struct cgroup_taskset *tset)
S
Stephane Eranian 已提交
10497
{
10498
	struct task_struct *task;
10499
	struct cgroup_subsys_state *css;
10500

10501
	cgroup_taskset_for_each(task, css, tset)
10502
		task_function_call(task, __perf_cgroup_move, task);
S
Stephane Eranian 已提交
10503 10504
}

10505
struct cgroup_subsys perf_event_cgrp_subsys = {
10506 10507
	.css_alloc	= perf_cgroup_css_alloc,
	.css_free	= perf_cgroup_css_free,
10508
	.attach		= perf_cgroup_attach,
S
Stephane Eranian 已提交
10509 10510
};
#endif /* CONFIG_CGROUP_PERF */