core.c 222.2 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 "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 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 = 1;
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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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	do_div(tmp, 100);
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	ACCESS_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;

	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;

	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 void perf_duration_warn(struct irq_work *w)
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{
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	u64 allowed_ns = ACCESS_ONCE(perf_sample_allowed_ns);
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	u64 avg_local_sample_len;
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	u64 local_samples_len;
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	local_samples_len = __this_cpu_read(running_sample_length);
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	avg_local_sample_len = local_samples_len/NR_ACCUMULATED_SAMPLES;

	printk_ratelimited(KERN_WARNING
			"perf interrupt took too long (%lld > %lld), lowering "
			"kernel.perf_event_max_sample_rate to %d\n",
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			avg_local_sample_len, allowed_ns >> 1,
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			sysctl_perf_event_sample_rate);
}

static DEFINE_IRQ_WORK(perf_duration_work, perf_duration_warn);

void perf_sample_event_took(u64 sample_len_ns)
{
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	u64 allowed_ns = ACCESS_ONCE(perf_sample_allowed_ns);
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	u64 avg_local_sample_len;
	u64 local_samples_len;
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	if (allowed_ns == 0)
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		return;

	/* decay the counter by 1 average sample */
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	local_samples_len = __this_cpu_read(running_sample_length);
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	local_samples_len -= local_samples_len/NR_ACCUMULATED_SAMPLES;
	local_samples_len += sample_len_ns;
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	__this_cpu_write(running_sample_length, local_samples_len);
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	/*
	 * note: this will be biased artifically low until we have
	 * seen NR_ACCUMULATED_SAMPLES.  Doing it this way keeps us
	 * from having to maintain a count.
	 */
	avg_local_sample_len = local_samples_len/NR_ACCUMULATED_SAMPLES;

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	if (avg_local_sample_len <= allowed_ns)
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		return;

	if (max_samples_per_tick <= 1)
		return;

	max_samples_per_tick = DIV_ROUND_UP(max_samples_per_tick, 2);
	sysctl_perf_event_sample_rate = max_samples_per_tick * HZ;
	perf_sample_period_ns = NSEC_PER_SEC / sysctl_perf_event_sample_rate;

	update_perf_cpu_limits();
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	if (!irq_work_queue(&perf_duration_work)) {
		early_printk("perf interrupt took too long (%lld > %lld), lowering "
			     "kernel.perf_event_max_sample_rate to %d\n",
			     avg_local_sample_len, allowed_ns >> 1,
			     sysctl_perf_event_sample_rate);
	}
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}

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

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

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

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

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

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#ifdef CONFIG_CGROUP_PERF

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

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

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

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

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

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

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

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

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

	now = perf_clock();

	info = this_cpu_ptr(cgrp->info);

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

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

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

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

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

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

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

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	cgrp = perf_cgroup_from_task(task, ctx);
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	info = this_cpu_ptr(cgrp->info);
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	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
 */
628
static void perf_cgroup_switch(struct task_struct *task, int mode)
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629 630 631 632 633 634 635 636 637 638 639 640 641 642 643 644 645 646 647
{
	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);
648 649
		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) {
659 660
			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) {
672
				WARN_ON_ONCE(cpuctx->cgrp);
673 674 675 676
				/*
				 * set cgrp before ctxsw in to allow
				 * event_filter_match() to not have to pass
				 * task around
677 678
				 * we pass the cpuctx->ctx to perf_cgroup_from_task()
				 * because cgorup events are only per-cpu
S
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679
				 */
680
				cpuctx->cgrp = perf_cgroup_from_task(task, &cpuctx->ctx);
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				cpu_ctx_sched_in(cpuctx, EVENT_ALL, task);
			}
683 684
			perf_pmu_enable(cpuctx->ctx.pmu);
			perf_ctx_unlock(cpuctx, cpuctx->task_ctx);
S
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		}
	}

	local_irq_restore(flags);
}

691 692
static inline void perf_cgroup_sched_out(struct task_struct *task,
					 struct task_struct *next)
S
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693
{
694 695 696
	struct perf_cgroup *cgrp1;
	struct perf_cgroup *cgrp2 = NULL;

697
	rcu_read_lock();
698 699
	/*
	 * we come here when we know perf_cgroup_events > 0
700 701
	 * we do not need to pass the ctx here because we know
	 * we are holding the rcu lock
702
	 */
703
	cgrp1 = perf_cgroup_from_task(task, NULL);
704
	cgrp2 = perf_cgroup_from_task(next, NULL);
705 706 707 708 709 710 711 712

	/*
	 * 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);
713 714

	rcu_read_unlock();
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715 716
}

717 718
static inline void perf_cgroup_sched_in(struct task_struct *prev,
					struct task_struct *task)
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719
{
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
	 */
729 730
	cgrp1 = perf_cgroup_from_task(task, NULL);
	cgrp2 = perf_cgroup_from_task(prev, NULL);
731 732 733 734 735 736 737 738

	/*
	 * 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);
739 740

	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;
749 750
	struct fd f = fdget(fd);
	int ret = 0;
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752
	if (!f.file)
S
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753 754
		return -EBADF;

A
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	css = css_tryget_online_from_dir(f.file->f_path.dentry,
756
					 &perf_event_cgrp_subsys);
757 758 759 760
	if (IS_ERR(css)) {
		ret = PTR_ERR(css);
		goto out;
	}
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761 762 763 764 765 766 767 768 769 770 771 772 773

	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;
	}
774
out:
775
	fdput(f);
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776 777 778 779 780 781 782 783 784 785 786 787 788 789 790 791 792 793 794 795 796 797 798 799 800 801 802 803 804 805 806 807 808 809 810 811 812 813 814 815 816 817 818 819 820 821 822 823 824 825 826 827 828 829 830 831 832 833 834 835 836 837 838 839 840 841 842 843 844 845 846 847 848
	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)
{
}

849 850
static inline void perf_cgroup_sched_out(struct task_struct *task,
					 struct task_struct *next)
S
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851 852 853
{
}

854 855
static inline void perf_cgroup_sched_in(struct task_struct *prev,
					struct task_struct *task)
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856 857 858 859 860 861 862 863 864 865 866
{
}

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
867 868
perf_cgroup_set_timestamp(struct task_struct *task,
			  struct perf_event_context *ctx)
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869 870 871 872 873 874 875 876 877 878 879 880 881 882 883 884 885 886 887 888 889 890 891 892 893 894 895 896 897 898
{
}

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

899 900 901 902 903 904 905 906
/*
 * 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
 */
907
static enum hrtimer_restart perf_mux_hrtimer_handler(struct hrtimer *hr)
908 909 910 911 912 913 914 915 916
{
	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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917 918
	raw_spin_lock(&cpuctx->hrtimer_lock);
	if (rotations)
919
		hrtimer_forward_now(hr, cpuctx->hrtimer_interval);
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920 921 922
	else
		cpuctx->hrtimer_active = 0;
	raw_spin_unlock(&cpuctx->hrtimer_lock);
923

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924
	return rotations ? HRTIMER_RESTART : HRTIMER_NORESTART;
925 926
}

927
static void __perf_mux_hrtimer_init(struct perf_cpu_context *cpuctx, int cpu)
928
{
929
	struct hrtimer *timer = &cpuctx->hrtimer;
930
	struct pmu *pmu = cpuctx->ctx.pmu;
931
	u64 interval;
932 933 934 935 936

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

937 938 939 940
	/*
	 * check default is sane, if not set then force to
	 * default interval (1/tick)
	 */
941 942 943
	interval = pmu->hrtimer_interval_ms;
	if (interval < 1)
		interval = pmu->hrtimer_interval_ms = PERF_CPU_HRTIMER;
944

945
	cpuctx->hrtimer_interval = ns_to_ktime(NSEC_PER_MSEC * interval);
946

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947 948
	raw_spin_lock_init(&cpuctx->hrtimer_lock);
	hrtimer_init(timer, CLOCK_MONOTONIC, HRTIMER_MODE_ABS_PINNED);
949
	timer->function = perf_mux_hrtimer_handler;
950 951
}

952
static int perf_mux_hrtimer_restart(struct perf_cpu_context *cpuctx)
953
{
954
	struct hrtimer *timer = &cpuctx->hrtimer;
955
	struct pmu *pmu = cpuctx->ctx.pmu;
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Peter Zijlstra 已提交
956
	unsigned long flags;
957 958 959

	/* not for SW PMU */
	if (pmu->task_ctx_nr == perf_sw_context)
960
		return 0;
961

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962 963 964 965 966 967 968
	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);
969

970
	return 0;
971 972
}

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973
void perf_pmu_disable(struct pmu *pmu)
974
{
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975 976 977
	int *count = this_cpu_ptr(pmu->pmu_disable_count);
	if (!(*count)++)
		pmu->pmu_disable(pmu);
978 979
}

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980
void perf_pmu_enable(struct pmu *pmu)
981
{
P
Peter Zijlstra 已提交
982 983 984
	int *count = this_cpu_ptr(pmu->pmu_disable_count);
	if (!--(*count))
		pmu->pmu_enable(pmu);
985 986
}

987
static DEFINE_PER_CPU(struct list_head, active_ctx_list);
988 989

/*
990 991 992 993
 * 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.
994
 */
995
static void perf_event_ctx_activate(struct perf_event_context *ctx)
996
{
997
	struct list_head *head = this_cpu_ptr(&active_ctx_list);
998

999
	WARN_ON(!irqs_disabled());
1000

1001 1002 1003 1004 1005 1006 1007 1008 1009 1010 1011 1012
	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);
1013 1014
}

1015
static void get_ctx(struct perf_event_context *ctx)
1016
{
1017
	WARN_ON(!atomic_inc_not_zero(&ctx->refcount));
1018 1019
}

1020 1021 1022 1023 1024 1025 1026 1027 1028
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);
}

1029
static void put_ctx(struct perf_event_context *ctx)
1030
{
1031 1032 1033
	if (atomic_dec_and_test(&ctx->refcount)) {
		if (ctx->parent_ctx)
			put_ctx(ctx->parent_ctx);
1034
		if (ctx->task && ctx->task != TASK_TOMBSTONE)
1035
			put_task_struct(ctx->task);
1036
		call_rcu(&ctx->rcu_head, free_ctx);
1037
	}
1038 1039
}

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Peter Zijlstra 已提交
1040 1041 1042 1043 1044 1045 1046
/*
 * 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.
 *
1047 1048 1049 1050
 * 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 ]
1051 1052
 *      perf_event_exit_event()
 *        put_event()			[ parent, 1 ]
1053 1054 1055 1056 1057 1058 1059 1060 1061 1062 1063 1064 1065 1066 1067 1068 1069
 *
 *  - 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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1070 1071 1072 1073 1074 1075 1076 1077 1078 1079 1080 1081 1082 1083 1084 1085 1086 1087 1088 1089 1090 1091 1092 1093 1094 1095
 *
 * 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:
 *	task_struct::perf_event_mutex
 *	  perf_event_context::mutex
 *	    perf_event::child_mutex;
P
Peter Zijlstra 已提交
1096
 *	      perf_event_context::lock
P
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1097 1098 1099
 *	    perf_event::mmap_mutex
 *	    mmap_sem
 */
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1100 1101
static struct perf_event_context *
perf_event_ctx_lock_nested(struct perf_event *event, int nesting)
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1102 1103 1104 1105 1106 1107 1108 1109 1110 1111 1112 1113
{
	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();

P
Peter Zijlstra 已提交
1114
	mutex_lock_nested(&ctx->mutex, nesting);
P
Peter Zijlstra 已提交
1115 1116 1117 1118 1119 1120 1121 1122 1123
	if (event->ctx != ctx) {
		mutex_unlock(&ctx->mutex);
		put_ctx(ctx);
		goto again;
	}

	return ctx;
}

P
Peter Zijlstra 已提交
1124 1125 1126 1127 1128 1129
static inline struct perf_event_context *
perf_event_ctx_lock(struct perf_event *event)
{
	return perf_event_ctx_lock_nested(event, 0);
}

P
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1130 1131 1132 1133 1134 1135 1136
static void perf_event_ctx_unlock(struct perf_event *event,
				  struct perf_event_context *ctx)
{
	mutex_unlock(&ctx->mutex);
	put_ctx(ctx);
}

1137 1138 1139 1140 1141 1142 1143
/*
 * 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)
1144
{
1145 1146 1147 1148 1149
	struct perf_event_context *parent_ctx = ctx->parent_ctx;

	lockdep_assert_held(&ctx->lock);

	if (parent_ctx)
1150
		ctx->parent_ctx = NULL;
1151
	ctx->generation++;
1152 1153

	return parent_ctx;
1154 1155
}

1156 1157 1158 1159 1160 1161 1162 1163 1164 1165 1166 1167 1168 1169 1170 1171 1172 1173 1174 1175 1176 1177
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);
}

1178
/*
1179
 * If we inherit events we want to return the parent event id
1180 1181
 * to userspace.
 */
1182
static u64 primary_event_id(struct perf_event *event)
1183
{
1184
	u64 id = event->id;
1185

1186 1187
	if (event->parent)
		id = event->parent->id;
1188 1189 1190 1191

	return id;
}

1192
/*
1193
 * Get the perf_event_context for a task and lock it.
1194
 *
1195 1196 1197
 * This has to cope with with the fact that until it is locked,
 * the context could get moved to another task.
 */
1198
static struct perf_event_context *
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1199
perf_lock_task_context(struct task_struct *task, int ctxn, unsigned long *flags)
1200
{
1201
	struct perf_event_context *ctx;
1202

P
Peter Zijlstra 已提交
1203
retry:
1204 1205 1206
	/*
	 * One of the few rules of preemptible RCU is that one cannot do
	 * rcu_read_unlock() while holding a scheduler (or nested) lock when
1207
	 * part of the read side critical section was irqs-enabled -- see
1208 1209 1210
	 * rcu_read_unlock_special().
	 *
	 * Since ctx->lock nests under rq->lock we must ensure the entire read
1211
	 * side critical section has interrupts disabled.
1212
	 */
1213
	local_irq_save(*flags);
1214
	rcu_read_lock();
P
Peter Zijlstra 已提交
1215
	ctx = rcu_dereference(task->perf_event_ctxp[ctxn]);
1216 1217 1218 1219
	if (ctx) {
		/*
		 * If this context is a clone of another, it might
		 * get swapped for another underneath us by
1220
		 * perf_event_task_sched_out, though the
1221 1222 1223 1224 1225 1226
		 * 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.
		 */
1227
		raw_spin_lock(&ctx->lock);
P
Peter Zijlstra 已提交
1228
		if (ctx != rcu_dereference(task->perf_event_ctxp[ctxn])) {
1229
			raw_spin_unlock(&ctx->lock);
1230
			rcu_read_unlock();
1231
			local_irq_restore(*flags);
1232 1233
			goto retry;
		}
1234

1235 1236
		if (ctx->task == TASK_TOMBSTONE ||
		    !atomic_inc_not_zero(&ctx->refcount)) {
1237
			raw_spin_unlock(&ctx->lock);
1238
			ctx = NULL;
P
Peter Zijlstra 已提交
1239 1240
		} else {
			WARN_ON_ONCE(ctx->task != task);
1241
		}
1242 1243
	}
	rcu_read_unlock();
1244 1245
	if (!ctx)
		local_irq_restore(*flags);
1246 1247 1248 1249 1250 1251 1252 1253
	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
1254 1255
static struct perf_event_context *
perf_pin_task_context(struct task_struct *task, int ctxn)
1256
{
1257
	struct perf_event_context *ctx;
1258 1259
	unsigned long flags;

P
Peter Zijlstra 已提交
1260
	ctx = perf_lock_task_context(task, ctxn, &flags);
1261 1262
	if (ctx) {
		++ctx->pin_count;
1263
		raw_spin_unlock_irqrestore(&ctx->lock, flags);
1264 1265 1266 1267
	}
	return ctx;
}

1268
static void perf_unpin_context(struct perf_event_context *ctx)
1269 1270 1271
{
	unsigned long flags;

1272
	raw_spin_lock_irqsave(&ctx->lock, flags);
1273
	--ctx->pin_count;
1274
	raw_spin_unlock_irqrestore(&ctx->lock, flags);
1275 1276
}

1277 1278 1279 1280 1281 1282 1283 1284 1285 1286 1287
/*
 * 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;
}

1288 1289 1290
static u64 perf_event_time(struct perf_event *event)
{
	struct perf_event_context *ctx = event->ctx;
S
Stephane Eranian 已提交
1291 1292 1293 1294

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

1295 1296 1297
	return ctx ? ctx->time : 0;
}

1298 1299 1300 1301 1302 1303 1304 1305
/*
 * 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;

1306 1307
	lockdep_assert_held(&ctx->lock);

1308 1309 1310
	if (event->state < PERF_EVENT_STATE_INACTIVE ||
	    event->group_leader->state < PERF_EVENT_STATE_INACTIVE)
		return;
1311

S
Stephane Eranian 已提交
1312 1313 1314 1315 1316 1317 1318 1319 1320 1321 1322
	/*
	 * 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))
1323
		run_end = perf_cgroup_event_time(event);
S
Stephane Eranian 已提交
1324 1325
	else if (ctx->is_active)
		run_end = ctx->time;
1326 1327 1328 1329
	else
		run_end = event->tstamp_stopped;

	event->total_time_enabled = run_end - event->tstamp_enabled;
1330 1331 1332 1333

	if (event->state == PERF_EVENT_STATE_INACTIVE)
		run_end = event->tstamp_stopped;
	else
1334
		run_end = perf_event_time(event);
1335 1336

	event->total_time_running = run_end - event->tstamp_running;
S
Stephane Eranian 已提交
1337

1338 1339
}

1340 1341 1342 1343 1344 1345 1346 1347 1348 1349 1350 1351
/*
 * 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);
}

1352 1353 1354 1355 1356 1357 1358 1359 1360
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;
}

1361
/*
1362
 * Add a event from the lists for its context.
1363 1364
 * Must be called with ctx->mutex and ctx->lock held.
 */
1365
static void
1366
list_add_event(struct perf_event *event, struct perf_event_context *ctx)
1367
{
P
Peter Zijlstra 已提交
1368 1369
	lockdep_assert_held(&ctx->lock);

1370 1371
	WARN_ON_ONCE(event->attach_state & PERF_ATTACH_CONTEXT);
	event->attach_state |= PERF_ATTACH_CONTEXT;
1372 1373

	/*
1374 1375 1376
	 * 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.
1377
	 */
1378
	if (event->group_leader == event) {
1379 1380
		struct list_head *list;

1381 1382 1383
		if (is_software_event(event))
			event->group_flags |= PERF_GROUP_SOFTWARE;

1384 1385
		list = ctx_group_list(event, ctx);
		list_add_tail(&event->group_entry, list);
P
Peter Zijlstra 已提交
1386
	}
P
Peter Zijlstra 已提交
1387

1388
	if (is_cgroup_event(event))
S
Stephane Eranian 已提交
1389 1390
		ctx->nr_cgroups++;

1391 1392 1393
	list_add_rcu(&event->event_entry, &ctx->event_list);
	ctx->nr_events++;
	if (event->attr.inherit_stat)
1394
		ctx->nr_stat++;
1395 1396

	ctx->generation++;
1397 1398
}

J
Jiri Olsa 已提交
1399 1400 1401 1402 1403 1404 1405 1406 1407
/*
 * 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
1408
static void __perf_event_read_size(struct perf_event *event, int nr_siblings)
1409 1410 1411 1412 1413 1414 1415 1416 1417 1418 1419 1420 1421 1422 1423
{
	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
1424
		nr += nr_siblings;
1425 1426 1427 1428 1429 1430 1431
		size += sizeof(u64);
	}

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

P
Peter Zijlstra 已提交
1432
static void __perf_event_header_size(struct perf_event *event, u64 sample_type)
1433 1434 1435 1436 1437 1438 1439
{
	struct perf_sample_data *data;
	u16 size = 0;

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

1440 1441 1442 1443 1444 1445
	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
1446 1447 1448
	if (sample_type & PERF_SAMPLE_WEIGHT)
		size += sizeof(data->weight);

1449 1450 1451
	if (sample_type & PERF_SAMPLE_READ)
		size += event->read_size;

1452 1453 1454
	if (sample_type & PERF_SAMPLE_DATA_SRC)
		size += sizeof(data->data_src.val);

A
Andi Kleen 已提交
1455 1456 1457
	if (sample_type & PERF_SAMPLE_TRANSACTION)
		size += sizeof(data->txn);

1458 1459 1460
	event->header_size = size;
}

P
Peter Zijlstra 已提交
1461 1462 1463 1464 1465 1466 1467 1468 1469 1470 1471
/*
 * 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);
}

1472 1473 1474 1475 1476 1477
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;

1478 1479 1480 1481 1482 1483
	if (sample_type & PERF_SAMPLE_TID)
		size += sizeof(data->tid_entry);

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

1484 1485 1486
	if (sample_type & PERF_SAMPLE_IDENTIFIER)
		size += sizeof(data->id);

1487 1488 1489 1490 1491 1492 1493 1494 1495
	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);

1496
	event->id_header_size = size;
1497 1498
}

P
Peter Zijlstra 已提交
1499 1500 1501 1502 1503 1504 1505 1506 1507 1508 1509 1510 1511 1512 1513 1514 1515 1516 1517 1518 1519
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;
}

1520 1521
static void perf_group_attach(struct perf_event *event)
{
1522
	struct perf_event *group_leader = event->group_leader, *pos;
1523

P
Peter Zijlstra 已提交
1524 1525 1526 1527 1528 1529
	/*
	 * We can have double attach due to group movement in perf_event_open.
	 */
	if (event->attach_state & PERF_ATTACH_GROUP)
		return;

1530 1531 1532 1533 1534
	event->attach_state |= PERF_ATTACH_GROUP;

	if (group_leader == event)
		return;

P
Peter Zijlstra 已提交
1535 1536
	WARN_ON_ONCE(group_leader->ctx != event->ctx);

1537 1538 1539 1540 1541 1542
	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++;
1543 1544 1545 1546 1547

	perf_event__header_size(group_leader);

	list_for_each_entry(pos, &group_leader->sibling_list, group_entry)
		perf_event__header_size(pos);
1548 1549
}

1550
/*
1551
 * Remove a event from the lists for its context.
1552
 * Must be called with ctx->mutex and ctx->lock held.
1553
 */
1554
static void
1555
list_del_event(struct perf_event *event, struct perf_event_context *ctx)
1556
{
1557
	struct perf_cpu_context *cpuctx;
P
Peter Zijlstra 已提交
1558 1559 1560 1561

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

1562 1563 1564 1565
	/*
	 * We can have double detach due to exit/hot-unplug + close.
	 */
	if (!(event->attach_state & PERF_ATTACH_CONTEXT))
1566
		return;
1567 1568 1569

	event->attach_state &= ~PERF_ATTACH_CONTEXT;

1570
	if (is_cgroup_event(event)) {
S
Stephane Eranian 已提交
1571
		ctx->nr_cgroups--;
1572 1573 1574 1575
		/*
		 * Because cgroup events are always per-cpu events, this will
		 * always be called from the right CPU.
		 */
1576 1577
		cpuctx = __get_cpu_context(ctx);
		/*
1578 1579
		 * If there are no more cgroup events then clear cgrp to avoid
		 * stale pointer in update_cgrp_time_from_cpuctx().
1580 1581 1582 1583
		 */
		if (!ctx->nr_cgroups)
			cpuctx->cgrp = NULL;
	}
S
Stephane Eranian 已提交
1584

1585 1586
	ctx->nr_events--;
	if (event->attr.inherit_stat)
1587
		ctx->nr_stat--;
1588

1589
	list_del_rcu(&event->event_entry);
1590

1591 1592
	if (event->group_leader == event)
		list_del_init(&event->group_entry);
P
Peter Zijlstra 已提交
1593

1594
	update_group_times(event);
1595 1596 1597 1598 1599 1600 1601 1602 1603 1604

	/*
	 * 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;
1605 1606

	ctx->generation++;
1607 1608
}

1609
static void perf_group_detach(struct perf_event *event)
1610 1611
{
	struct perf_event *sibling, *tmp;
1612 1613 1614 1615 1616 1617 1618 1619 1620 1621 1622 1623 1624 1625 1626 1627
	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--;
1628
		goto out;
1629 1630 1631 1632
	}

	if (!list_empty(&event->group_entry))
		list = &event->group_entry;
1633

1634
	/*
1635 1636
	 * If this was a group event with sibling events then
	 * upgrade the siblings to singleton events by adding them
1637
	 * to whatever list we are on.
1638
	 */
1639
	list_for_each_entry_safe(sibling, tmp, &event->sibling_list, group_entry) {
1640 1641
		if (list)
			list_move_tail(&sibling->group_entry, list);
1642
		sibling->group_leader = sibling;
1643 1644 1645

		/* Inherit group flags from the previous leader */
		sibling->group_flags = event->group_flags;
P
Peter Zijlstra 已提交
1646 1647

		WARN_ON_ONCE(sibling->ctx != event->ctx);
1648
	}
1649 1650 1651 1652 1653 1654

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);
1655 1656
}

1657 1658
static bool is_orphaned_event(struct perf_event *event)
{
P
Peter Zijlstra 已提交
1659
	return event->state == PERF_EVENT_STATE_DEAD;
1660 1661
}

1662 1663 1664 1665 1666 1667
static inline int pmu_filter_match(struct perf_event *event)
{
	struct pmu *pmu = event->pmu;
	return pmu->filter_match ? pmu->filter_match(event) : 1;
}

1668 1669 1670
static inline int
event_filter_match(struct perf_event *event)
{
S
Stephane Eranian 已提交
1671
	return (event->cpu == -1 || event->cpu == smp_processor_id())
1672
	    && perf_cgroup_match(event) && pmu_filter_match(event);
1673 1674
}

1675 1676
static void
event_sched_out(struct perf_event *event,
1677
		  struct perf_cpu_context *cpuctx,
1678
		  struct perf_event_context *ctx)
1679
{
1680
	u64 tstamp = perf_event_time(event);
1681
	u64 delta;
P
Peter Zijlstra 已提交
1682 1683 1684 1685

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

1686 1687 1688 1689 1690 1691 1692 1693
	/*
	 * 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
1694
		delta = tstamp - event->tstamp_stopped;
1695
		event->tstamp_running += delta;
1696
		event->tstamp_stopped = tstamp;
1697 1698
	}

1699
	if (event->state != PERF_EVENT_STATE_ACTIVE)
1700
		return;
1701

1702 1703
	perf_pmu_disable(event->pmu);

1704 1705 1706
	event->tstamp_stopped = tstamp;
	event->pmu->del(event, 0);
	event->oncpu = -1;
1707 1708 1709 1710
	event->state = PERF_EVENT_STATE_INACTIVE;
	if (event->pending_disable) {
		event->pending_disable = 0;
		event->state = PERF_EVENT_STATE_OFF;
1711
	}
1712

1713
	if (!is_software_event(event))
1714
		cpuctx->active_oncpu--;
1715 1716
	if (!--ctx->nr_active)
		perf_event_ctx_deactivate(ctx);
1717 1718
	if (event->attr.freq && event->attr.sample_freq)
		ctx->nr_freq--;
1719
	if (event->attr.exclusive || !cpuctx->active_oncpu)
1720
		cpuctx->exclusive = 0;
1721 1722

	perf_pmu_enable(event->pmu);
1723 1724
}

1725
static void
1726
group_sched_out(struct perf_event *group_event,
1727
		struct perf_cpu_context *cpuctx,
1728
		struct perf_event_context *ctx)
1729
{
1730
	struct perf_event *event;
1731
	int state = group_event->state;
1732

1733
	event_sched_out(group_event, cpuctx, ctx);
1734 1735 1736 1737

	/*
	 * Schedule out siblings (if any):
	 */
1738 1739
	list_for_each_entry(event, &group_event->sibling_list, group_entry)
		event_sched_out(event, cpuctx, ctx);
1740

1741
	if (state == PERF_EVENT_STATE_ACTIVE && group_event->attr.exclusive)
1742 1743 1744
		cpuctx->exclusive = 0;
}

1745
#define DETACH_GROUP	0x01UL
1746

T
Thomas Gleixner 已提交
1747
/*
1748
 * Cross CPU call to remove a performance event
T
Thomas Gleixner 已提交
1749
 *
1750
 * We disable the event on the hardware level first. After that we
T
Thomas Gleixner 已提交
1751 1752
 * remove it from the context list.
 */
1753 1754 1755 1756 1757
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
1758
{
1759
	unsigned long flags = (unsigned long)info;
T
Thomas Gleixner 已提交
1760

1761
	event_sched_out(event, cpuctx, ctx);
1762
	if (flags & DETACH_GROUP)
1763
		perf_group_detach(event);
1764
	list_del_event(event, ctx);
1765 1766

	if (!ctx->nr_events && ctx->is_active) {
1767
		ctx->is_active = 0;
1768 1769 1770 1771
		if (ctx->task) {
			WARN_ON_ONCE(cpuctx->task_ctx != ctx);
			cpuctx->task_ctx = NULL;
		}
1772
	}
T
Thomas Gleixner 已提交
1773 1774 1775
}

/*
1776
 * Remove the event from a task's (or a CPU's) list of events.
T
Thomas Gleixner 已提交
1777
 *
1778 1779
 * If event->ctx is a cloned context, callers must make sure that
 * every task struct that event->ctx->task could possibly point to
1780 1781
 * 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.
1782
 * When called from perf_event_exit_task, it's OK because the
1783
 * context has been detached from its task.
T
Thomas Gleixner 已提交
1784
 */
1785
static void perf_remove_from_context(struct perf_event *event, unsigned long flags)
T
Thomas Gleixner 已提交
1786
{
1787
	lockdep_assert_held(&event->ctx->mutex);
T
Thomas Gleixner 已提交
1788

1789
	event_function_call(event, __perf_remove_from_context, (void *)flags);
T
Thomas Gleixner 已提交
1790 1791
}

1792
/*
1793
 * Cross CPU call to disable a performance event
1794
 */
1795 1796 1797 1798
static void __perf_event_disable(struct perf_event *event,
				 struct perf_cpu_context *cpuctx,
				 struct perf_event_context *ctx,
				 void *info)
1799
{
1800 1801
	if (event->state < PERF_EVENT_STATE_INACTIVE)
		return;
1802

1803 1804 1805 1806 1807 1808 1809 1810
	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;
1811 1812
}

1813
/*
1814
 * Disable a event.
1815
 *
1816 1817
 * If event->ctx is a cloned context, callers must make sure that
 * every task struct that event->ctx->task could possibly point to
1818
 * remains valid.  This condition is satisifed when called through
1819 1820
 * perf_event_for_each_child or perf_event_for_each because they
 * hold the top-level event's child_mutex, so any descendant that
1821 1822
 * goes to exit will block in perf_event_exit_event().
 *
1823
 * When called from perf_pending_event it's OK because event->ctx
1824
 * is the current context on this CPU and preemption is disabled,
1825
 * hence we can't get into perf_event_task_sched_out for this context.
1826
 */
P
Peter Zijlstra 已提交
1827
static void _perf_event_disable(struct perf_event *event)
1828
{
1829
	struct perf_event_context *ctx = event->ctx;
1830

1831
	raw_spin_lock_irq(&ctx->lock);
1832
	if (event->state <= PERF_EVENT_STATE_OFF) {
1833
		raw_spin_unlock_irq(&ctx->lock);
1834
		return;
1835
	}
1836
	raw_spin_unlock_irq(&ctx->lock);
1837

1838 1839 1840 1841 1842 1843
	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);
1844
}
P
Peter Zijlstra 已提交
1845 1846 1847 1848 1849 1850 1851 1852 1853 1854 1855 1856 1857

/*
 * 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);
}
1858
EXPORT_SYMBOL_GPL(perf_event_disable);
1859

S
Stephane Eranian 已提交
1860 1861 1862 1863 1864 1865 1866 1867 1868 1869 1870 1871 1872 1873 1874 1875 1876 1877 1878 1879 1880 1881 1882 1883 1884 1885 1886 1887 1888 1889 1890 1891 1892 1893 1894
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
1895 1896 1897
#define MAX_INTERRUPTS (~0ULL)

static void perf_log_throttle(struct perf_event *event, int enable);
1898
static void perf_log_itrace_start(struct perf_event *event);
P
Peter Zijlstra 已提交
1899

1900
static int
1901
event_sched_in(struct perf_event *event,
1902
		 struct perf_cpu_context *cpuctx,
1903
		 struct perf_event_context *ctx)
1904
{
1905
	u64 tstamp = perf_event_time(event);
1906
	int ret = 0;
1907

1908 1909
	lockdep_assert_held(&ctx->lock);

1910
	if (event->state <= PERF_EVENT_STATE_OFF)
1911 1912
		return 0;

1913
	event->state = PERF_EVENT_STATE_ACTIVE;
1914
	event->oncpu = smp_processor_id();
P
Peter Zijlstra 已提交
1915 1916 1917 1918 1919 1920 1921 1922 1923 1924 1925

	/*
	 * 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;
	}

1926 1927 1928 1929 1930
	/*
	 * The new state must be visible before we turn it on in the hardware:
	 */
	smp_wmb();

1931 1932
	perf_pmu_disable(event->pmu);

1933 1934
	perf_set_shadow_time(event, ctx, tstamp);

1935 1936
	perf_log_itrace_start(event);

P
Peter Zijlstra 已提交
1937
	if (event->pmu->add(event, PERF_EF_START)) {
1938 1939
		event->state = PERF_EVENT_STATE_INACTIVE;
		event->oncpu = -1;
1940 1941
		ret = -EAGAIN;
		goto out;
1942 1943
	}

1944 1945
	event->tstamp_running += tstamp - event->tstamp_stopped;

1946
	if (!is_software_event(event))
1947
		cpuctx->active_oncpu++;
1948 1949
	if (!ctx->nr_active++)
		perf_event_ctx_activate(ctx);
1950 1951
	if (event->attr.freq && event->attr.sample_freq)
		ctx->nr_freq++;
1952

1953
	if (event->attr.exclusive)
1954 1955
		cpuctx->exclusive = 1;

1956 1957 1958 1959
out:
	perf_pmu_enable(event->pmu);

	return ret;
1960 1961
}

1962
static int
1963
group_sched_in(struct perf_event *group_event,
1964
	       struct perf_cpu_context *cpuctx,
1965
	       struct perf_event_context *ctx)
1966
{
1967
	struct perf_event *event, *partial_group = NULL;
P
Peter Zijlstra 已提交
1968
	struct pmu *pmu = ctx->pmu;
1969 1970
	u64 now = ctx->time;
	bool simulate = false;
1971

1972
	if (group_event->state == PERF_EVENT_STATE_OFF)
1973 1974
		return 0;

1975
	pmu->start_txn(pmu, PERF_PMU_TXN_ADD);
1976

1977
	if (event_sched_in(group_event, cpuctx, ctx)) {
P
Peter Zijlstra 已提交
1978
		pmu->cancel_txn(pmu);
1979
		perf_mux_hrtimer_restart(cpuctx);
1980
		return -EAGAIN;
1981
	}
1982 1983 1984 1985

	/*
	 * Schedule in siblings as one group (if any):
	 */
1986
	list_for_each_entry(event, &group_event->sibling_list, group_entry) {
1987
		if (event_sched_in(event, cpuctx, ctx)) {
1988
			partial_group = event;
1989 1990 1991 1992
			goto group_error;
		}
	}

1993
	if (!pmu->commit_txn(pmu))
1994
		return 0;
1995

1996 1997 1998 1999
group_error:
	/*
	 * Groups can be scheduled in as one unit only, so undo any
	 * partial group before returning:
2000 2001 2002 2003 2004 2005 2006 2007 2008 2009
	 * 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.
2010
	 */
2011 2012
	list_for_each_entry(event, &group_event->sibling_list, group_entry) {
		if (event == partial_group)
2013 2014 2015 2016 2017 2018 2019 2020
			simulate = true;

		if (simulate) {
			event->tstamp_running += now - event->tstamp_stopped;
			event->tstamp_stopped = now;
		} else {
			event_sched_out(event, cpuctx, ctx);
		}
2021
	}
2022
	event_sched_out(group_event, cpuctx, ctx);
2023

P
Peter Zijlstra 已提交
2024
	pmu->cancel_txn(pmu);
2025

2026
	perf_mux_hrtimer_restart(cpuctx);
2027

2028 2029 2030
	return -EAGAIN;
}

2031
/*
2032
 * Work out whether we can put this event group on the CPU now.
2033
 */
2034
static int group_can_go_on(struct perf_event *event,
2035 2036 2037 2038
			   struct perf_cpu_context *cpuctx,
			   int can_add_hw)
{
	/*
2039
	 * Groups consisting entirely of software events can always go on.
2040
	 */
2041
	if (event->group_flags & PERF_GROUP_SOFTWARE)
2042 2043 2044
		return 1;
	/*
	 * If an exclusive group is already on, no other hardware
2045
	 * events can go on.
2046 2047 2048 2049 2050
	 */
	if (cpuctx->exclusive)
		return 0;
	/*
	 * If this group is exclusive and there are already
2051
	 * events on the CPU, it can't go on.
2052
	 */
2053
	if (event->attr.exclusive && cpuctx->active_oncpu)
2054 2055 2056 2057 2058 2059 2060 2061
		return 0;
	/*
	 * Otherwise, try to add it if all previous groups were able
	 * to go on.
	 */
	return can_add_hw;
}

2062 2063
static void add_event_to_ctx(struct perf_event *event,
			       struct perf_event_context *ctx)
2064
{
2065 2066
	u64 tstamp = perf_event_time(event);

2067
	list_add_event(event, ctx);
2068
	perf_group_attach(event);
2069 2070 2071
	event->tstamp_enabled = tstamp;
	event->tstamp_running = tstamp;
	event->tstamp_stopped = tstamp;
2072 2073
}

2074 2075 2076
static void ctx_sched_out(struct perf_event_context *ctx,
			  struct perf_cpu_context *cpuctx,
			  enum event_type_t event_type);
2077 2078 2079 2080 2081
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);
2082

2083 2084 2085 2086 2087 2088 2089 2090 2091 2092 2093 2094
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);
}

2095 2096 2097 2098 2099 2100 2101 2102 2103 2104 2105 2106
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);
}

2107 2108
static void ctx_resched(struct perf_cpu_context *cpuctx,
			struct perf_event_context *task_ctx)
2109
{
2110 2111 2112 2113 2114 2115
	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);
2116 2117
}

T
Thomas Gleixner 已提交
2118
/*
2119
 * Cross CPU call to install and enable a performance event
2120
 *
2121 2122
 * 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
2123
 */
2124
static int  __perf_install_in_context(void *info)
T
Thomas Gleixner 已提交
2125
{
2126 2127
	struct perf_event *event = info;
	struct perf_event_context *ctx = event->ctx;
P
Peter Zijlstra 已提交
2128
	struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
2129
	struct perf_event_context *task_ctx = cpuctx->task_ctx;
2130 2131
	bool activate = true;
	int ret = 0;
T
Thomas Gleixner 已提交
2132

2133
	raw_spin_lock(&cpuctx->ctx.lock);
2134
	if (ctx->task) {
2135 2136
		raw_spin_lock(&ctx->lock);
		task_ctx = ctx;
2137 2138 2139 2140

		/* If we're on the wrong CPU, try again */
		if (task_cpu(ctx->task) != smp_processor_id()) {
			ret = -ESRCH;
2141
			goto unlock;
2142
		}
2143

2144
		/*
2145 2146 2147
		 * 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.
2148
		 */
2149 2150 2151 2152 2153
		if (ctx->task != current)
			activate = false;
		else
			WARN_ON_ONCE(cpuctx->task_ctx && cpuctx->task_ctx != ctx);

2154 2155
	} else if (task_ctx) {
		raw_spin_lock(&task_ctx->lock);
2156
	}
2157

2158 2159 2160 2161 2162 2163 2164 2165
	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);
	}

2166
unlock:
2167
	perf_ctx_unlock(cpuctx, task_ctx);
2168

2169
	return ret;
T
Thomas Gleixner 已提交
2170 2171 2172
}

/*
2173 2174 2175
 * Attach a performance event to a context.
 *
 * Very similar to event_function_call, see comment there.
T
Thomas Gleixner 已提交
2176 2177
 */
static void
2178 2179
perf_install_in_context(struct perf_event_context *ctx,
			struct perf_event *event,
T
Thomas Gleixner 已提交
2180 2181
			int cpu)
{
2182
	struct task_struct *task = READ_ONCE(ctx->task);
2183

2184 2185
	lockdep_assert_held(&ctx->mutex);

2186
	event->ctx = ctx;
2187 2188
	if (event->cpu != -1)
		event->cpu = cpu;
2189

2190 2191 2192 2193 2194 2195 2196 2197 2198 2199 2200
	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;

2201 2202 2203 2204
	/*
	 * 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.
	 */
2205
again:
2206
	/*
2207 2208
	 * Cannot use task_function_call() because we need to run on the task's
	 * CPU regardless of whether its current or not.
2209
	 */
2210 2211 2212 2213 2214
	if (!cpu_function_call(task_cpu(task), __perf_install_in_context, event))
		return;

	raw_spin_lock_irq(&ctx->lock);
	task = ctx->task;
2215
	if (WARN_ON_ONCE(task == TASK_TOMBSTONE)) {
2216 2217 2218 2219 2220
		/*
		 * 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().
		 */
2221 2222 2223
		raw_spin_unlock_irq(&ctx->lock);
		return;
	}
2224 2225
	raw_spin_unlock_irq(&ctx->lock);
	/*
2226 2227
	 * Since !ctx->is_active doesn't mean anything, we must IPI
	 * unconditionally.
2228
	 */
2229
	goto again;
T
Thomas Gleixner 已提交
2230 2231
}

2232
/*
2233
 * Put a event into inactive state and update time fields.
2234 2235 2236 2237 2238 2239
 * 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.
 */
2240
static void __perf_event_mark_enabled(struct perf_event *event)
2241
{
2242
	struct perf_event *sub;
2243
	u64 tstamp = perf_event_time(event);
2244

2245
	event->state = PERF_EVENT_STATE_INACTIVE;
2246
	event->tstamp_enabled = tstamp - event->total_time_enabled;
P
Peter Zijlstra 已提交
2247
	list_for_each_entry(sub, &event->sibling_list, group_entry) {
2248 2249
		if (sub->state >= PERF_EVENT_STATE_INACTIVE)
			sub->tstamp_enabled = tstamp - sub->total_time_enabled;
P
Peter Zijlstra 已提交
2250
	}
2251 2252
}

2253
/*
2254
 * Cross CPU call to enable a performance event
2255
 */
2256 2257 2258 2259
static void __perf_event_enable(struct perf_event *event,
				struct perf_cpu_context *cpuctx,
				struct perf_event_context *ctx,
				void *info)
2260
{
2261
	struct perf_event *leader = event->group_leader;
2262
	struct perf_event_context *task_ctx;
2263

P
Peter Zijlstra 已提交
2264 2265
	if (event->state >= PERF_EVENT_STATE_INACTIVE ||
	    event->state <= PERF_EVENT_STATE_ERROR)
2266
		return;
2267

2268 2269 2270
	if (ctx->is_active)
		ctx_sched_out(ctx, cpuctx, EVENT_TIME);

2271
	__perf_event_mark_enabled(event);
2272

2273 2274 2275
	if (!ctx->is_active)
		return;

S
Stephane Eranian 已提交
2276
	if (!event_filter_match(event)) {
2277
		if (is_cgroup_event(event))
S
Stephane Eranian 已提交
2278
			perf_cgroup_defer_enabled(event);
2279
		ctx_sched_in(ctx, cpuctx, EVENT_TIME, current);
2280
		return;
S
Stephane Eranian 已提交
2281
	}
2282

2283
	/*
2284
	 * If the event is in a group and isn't the group leader,
2285
	 * then don't put it on unless the group is on.
2286
	 */
2287 2288
	if (leader != event && leader->state != PERF_EVENT_STATE_ACTIVE) {
		ctx_sched_in(ctx, cpuctx, EVENT_TIME, current);
2289
		return;
2290
	}
2291

2292 2293 2294
	task_ctx = cpuctx->task_ctx;
	if (ctx->task)
		WARN_ON_ONCE(task_ctx != ctx);
2295

2296
	ctx_resched(cpuctx, task_ctx);
2297 2298
}

2299
/*
2300
 * Enable a event.
2301
 *
2302 2303
 * If event->ctx is a cloned context, callers must make sure that
 * every task struct that event->ctx->task could possibly point to
2304
 * remains valid.  This condition is satisfied when called through
2305 2306
 * perf_event_for_each_child or perf_event_for_each as described
 * for perf_event_disable.
2307
 */
P
Peter Zijlstra 已提交
2308
static void _perf_event_enable(struct perf_event *event)
2309
{
2310
	struct perf_event_context *ctx = event->ctx;
2311

2312
	raw_spin_lock_irq(&ctx->lock);
P
Peter Zijlstra 已提交
2313 2314
	if (event->state >= PERF_EVENT_STATE_INACTIVE ||
	    event->state <  PERF_EVENT_STATE_ERROR) {
2315
		raw_spin_unlock_irq(&ctx->lock);
2316 2317 2318 2319
		return;
	}

	/*
2320
	 * If the event is in error state, clear that first.
2321 2322 2323 2324
	 *
	 * 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.
2325
	 */
2326 2327
	if (event->state == PERF_EVENT_STATE_ERROR)
		event->state = PERF_EVENT_STATE_OFF;
2328
	raw_spin_unlock_irq(&ctx->lock);
2329

2330
	event_function_call(event, __perf_event_enable, NULL);
2331
}
P
Peter Zijlstra 已提交
2332 2333 2334 2335 2336 2337 2338 2339 2340 2341 2342 2343

/*
 * 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);
}
2344
EXPORT_SYMBOL_GPL(perf_event_enable);
2345

P
Peter Zijlstra 已提交
2346
static int _perf_event_refresh(struct perf_event *event, int refresh)
2347
{
2348
	/*
2349
	 * not supported on inherited events
2350
	 */
2351
	if (event->attr.inherit || !is_sampling_event(event))
2352 2353
		return -EINVAL;

2354
	atomic_add(refresh, &event->event_limit);
P
Peter Zijlstra 已提交
2355
	_perf_event_enable(event);
2356 2357

	return 0;
2358
}
P
Peter Zijlstra 已提交
2359 2360 2361 2362 2363 2364 2365 2366 2367 2368 2369 2370 2371 2372 2373

/*
 * 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;
}
2374
EXPORT_SYMBOL_GPL(perf_event_refresh);
2375

2376 2377 2378
static void ctx_sched_out(struct perf_event_context *ctx,
			  struct perf_cpu_context *cpuctx,
			  enum event_type_t event_type)
2379
{
2380
	int is_active = ctx->is_active;
P
Peter Zijlstra 已提交
2381
	struct perf_event *event;
2382

P
Peter Zijlstra 已提交
2383
	lockdep_assert_held(&ctx->lock);
2384

2385 2386 2387 2388 2389 2390 2391
	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);
2392
		return;
2393 2394
	}

2395
	ctx->is_active &= ~event_type;
2396 2397 2398
	if (!(ctx->is_active & EVENT_ALL))
		ctx->is_active = 0;

2399 2400 2401 2402 2403
	if (ctx->task) {
		WARN_ON_ONCE(cpuctx->task_ctx != ctx);
		if (!ctx->is_active)
			cpuctx->task_ctx = NULL;
	}
2404

2405 2406 2407 2408 2409 2410 2411 2412 2413
	is_active ^= ctx->is_active; /* changed bits */

	if (is_active & EVENT_TIME) {
		/* update (and stop) ctx time */
		update_context_time(ctx);
		update_cgrp_time_from_cpuctx(cpuctx);
	}

	if (!ctx->nr_active || !(is_active & EVENT_ALL))
2414
		return;
2415

P
Peter Zijlstra 已提交
2416
	perf_pmu_disable(ctx->pmu);
2417
	if (is_active & EVENT_PINNED) {
2418 2419
		list_for_each_entry(event, &ctx->pinned_groups, group_entry)
			group_sched_out(event, cpuctx, ctx);
P
Peter Zijlstra 已提交
2420
	}
2421

2422
	if (is_active & EVENT_FLEXIBLE) {
2423
		list_for_each_entry(event, &ctx->flexible_groups, group_entry)
2424
			group_sched_out(event, cpuctx, ctx);
P
Peter Zijlstra 已提交
2425
	}
P
Peter Zijlstra 已提交
2426
	perf_pmu_enable(ctx->pmu);
2427 2428
}

2429
/*
2430 2431 2432 2433 2434 2435
 * 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().
2436
 */
2437 2438
static int context_equiv(struct perf_event_context *ctx1,
			 struct perf_event_context *ctx2)
2439
{
2440 2441 2442
	lockdep_assert_held(&ctx1->lock);
	lockdep_assert_held(&ctx2->lock);

2443 2444 2445 2446 2447 2448 2449 2450 2451 2452 2453 2454 2455 2456 2457 2458 2459 2460 2461 2462 2463 2464
	/* 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;
2465 2466
}

2467 2468
static void __perf_event_sync_stat(struct perf_event *event,
				     struct perf_event *next_event)
2469 2470 2471
{
	u64 value;

2472
	if (!event->attr.inherit_stat)
2473 2474 2475
		return;

	/*
2476
	 * Update the event value, we cannot use perf_event_read()
2477 2478
	 * because we're in the middle of a context switch and have IRQs
	 * disabled, which upsets smp_call_function_single(), however
2479
	 * we know the event must be on the current CPU, therefore we
2480 2481
	 * don't need to use it.
	 */
2482 2483
	switch (event->state) {
	case PERF_EVENT_STATE_ACTIVE:
2484 2485
		event->pmu->read(event);
		/* fall-through */
2486

2487 2488
	case PERF_EVENT_STATE_INACTIVE:
		update_event_times(event);
2489 2490 2491 2492 2493 2494 2495
		break;

	default:
		break;
	}

	/*
2496
	 * In order to keep per-task stats reliable we need to flip the event
2497 2498
	 * values when we flip the contexts.
	 */
2499 2500 2501
	value = local64_read(&next_event->count);
	value = local64_xchg(&event->count, value);
	local64_set(&next_event->count, value);
2502

2503 2504
	swap(event->total_time_enabled, next_event->total_time_enabled);
	swap(event->total_time_running, next_event->total_time_running);
2505

2506
	/*
2507
	 * Since we swizzled the values, update the user visible data too.
2508
	 */
2509 2510
	perf_event_update_userpage(event);
	perf_event_update_userpage(next_event);
2511 2512
}

2513 2514
static void perf_event_sync_stat(struct perf_event_context *ctx,
				   struct perf_event_context *next_ctx)
2515
{
2516
	struct perf_event *event, *next_event;
2517 2518 2519 2520

	if (!ctx->nr_stat)
		return;

2521 2522
	update_context_time(ctx);

2523 2524
	event = list_first_entry(&ctx->event_list,
				   struct perf_event, event_entry);
2525

2526 2527
	next_event = list_first_entry(&next_ctx->event_list,
					struct perf_event, event_entry);
2528

2529 2530
	while (&event->event_entry != &ctx->event_list &&
	       &next_event->event_entry != &next_ctx->event_list) {
2531

2532
		__perf_event_sync_stat(event, next_event);
2533

2534 2535
		event = list_next_entry(event, event_entry);
		next_event = list_next_entry(next_event, event_entry);
2536 2537 2538
	}
}

2539 2540
static void perf_event_context_sched_out(struct task_struct *task, int ctxn,
					 struct task_struct *next)
T
Thomas Gleixner 已提交
2541
{
P
Peter Zijlstra 已提交
2542
	struct perf_event_context *ctx = task->perf_event_ctxp[ctxn];
2543
	struct perf_event_context *next_ctx;
2544
	struct perf_event_context *parent, *next_parent;
P
Peter Zijlstra 已提交
2545
	struct perf_cpu_context *cpuctx;
2546
	int do_switch = 1;
T
Thomas Gleixner 已提交
2547

P
Peter Zijlstra 已提交
2548 2549
	if (likely(!ctx))
		return;
2550

P
Peter Zijlstra 已提交
2551 2552
	cpuctx = __get_cpu_context(ctx);
	if (!cpuctx->task_ctx)
T
Thomas Gleixner 已提交
2553 2554
		return;

2555
	rcu_read_lock();
P
Peter Zijlstra 已提交
2556
	next_ctx = next->perf_event_ctxp[ctxn];
2557 2558 2559 2560 2561 2562 2563
	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. */
2564
	if (!parent && !next_parent)
2565 2566 2567
		goto unlock;

	if (next_parent == ctx || next_ctx == parent || next_parent == parent) {
2568 2569 2570 2571 2572 2573 2574 2575 2576
		/*
		 * 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.
		 */
2577 2578
		raw_spin_lock(&ctx->lock);
		raw_spin_lock_nested(&next_ctx->lock, SINGLE_DEPTH_NESTING);
2579
		if (context_equiv(ctx, next_ctx)) {
2580 2581
			WRITE_ONCE(ctx->task, next);
			WRITE_ONCE(next_ctx->task, task);
2582 2583 2584

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

2585 2586 2587 2588 2589 2590 2591 2592 2593 2594
			/*
			 * 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);

2595
			do_switch = 0;
2596

2597
			perf_event_sync_stat(ctx, next_ctx);
2598
		}
2599 2600
		raw_spin_unlock(&next_ctx->lock);
		raw_spin_unlock(&ctx->lock);
2601
	}
2602
unlock:
2603
	rcu_read_unlock();
2604

2605
	if (do_switch) {
2606
		raw_spin_lock(&ctx->lock);
P
Peter Zijlstra 已提交
2607
		task_ctx_sched_out(cpuctx, ctx);
2608
		raw_spin_unlock(&ctx->lock);
2609
	}
T
Thomas Gleixner 已提交
2610 2611
}

2612 2613 2614 2615 2616 2617 2618 2619 2620 2621 2622 2623 2624 2625 2626 2627 2628 2629 2630 2631 2632 2633 2634 2635 2636 2637 2638 2639 2640 2641 2642 2643 2644 2645 2646 2647 2648 2649 2650 2651 2652 2653 2654 2655 2656 2657 2658 2659 2660 2661
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);
}

2662 2663 2664
static void perf_event_switch(struct task_struct *task,
			      struct task_struct *next_prev, bool sched_in);

P
Peter Zijlstra 已提交
2665 2666 2667 2668 2669 2670 2671 2672 2673 2674 2675 2676 2677 2678
#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.
 */
2679 2680
void __perf_event_task_sched_out(struct task_struct *task,
				 struct task_struct *next)
P
Peter Zijlstra 已提交
2681 2682 2683
{
	int ctxn;

2684 2685 2686
	if (__this_cpu_read(perf_sched_cb_usages))
		perf_pmu_sched_task(task, next, false);

2687 2688 2689
	if (atomic_read(&nr_switch_events))
		perf_event_switch(task, next, false);

P
Peter Zijlstra 已提交
2690 2691
	for_each_task_context_nr(ctxn)
		perf_event_context_sched_out(task, ctxn, next);
S
Stephane Eranian 已提交
2692 2693 2694 2695 2696 2697

	/*
	 * 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
	 */
2698
	if (atomic_read(this_cpu_ptr(&perf_cgroup_events)))
2699
		perf_cgroup_sched_out(task, next);
P
Peter Zijlstra 已提交
2700 2701
}

2702 2703 2704 2705 2706 2707 2708
/*
 * 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);
2709 2710
}

2711
static void
2712
ctx_pinned_sched_in(struct perf_event_context *ctx,
2713
		    struct perf_cpu_context *cpuctx)
T
Thomas Gleixner 已提交
2714
{
2715
	struct perf_event *event;
T
Thomas Gleixner 已提交
2716

2717 2718
	list_for_each_entry(event, &ctx->pinned_groups, group_entry) {
		if (event->state <= PERF_EVENT_STATE_OFF)
2719
			continue;
2720
		if (!event_filter_match(event))
2721 2722
			continue;

S
Stephane Eranian 已提交
2723 2724 2725 2726
		/* may need to reset tstamp_enabled */
		if (is_cgroup_event(event))
			perf_cgroup_mark_enabled(event, ctx);

2727
		if (group_can_go_on(event, cpuctx, 1))
2728
			group_sched_in(event, cpuctx, ctx);
2729 2730 2731 2732 2733

		/*
		 * If this pinned group hasn't been scheduled,
		 * put it in error state.
		 */
2734 2735 2736
		if (event->state == PERF_EVENT_STATE_INACTIVE) {
			update_group_times(event);
			event->state = PERF_EVENT_STATE_ERROR;
2737
		}
2738
	}
2739 2740 2741 2742
}

static void
ctx_flexible_sched_in(struct perf_event_context *ctx,
2743
		      struct perf_cpu_context *cpuctx)
2744 2745 2746
{
	struct perf_event *event;
	int can_add_hw = 1;
2747

2748 2749 2750
	list_for_each_entry(event, &ctx->flexible_groups, group_entry) {
		/* Ignore events in OFF or ERROR state */
		if (event->state <= PERF_EVENT_STATE_OFF)
2751
			continue;
2752 2753
		/*
		 * Listen to the 'cpu' scheduling filter constraint
2754
		 * of events:
2755
		 */
2756
		if (!event_filter_match(event))
T
Thomas Gleixner 已提交
2757 2758
			continue;

S
Stephane Eranian 已提交
2759 2760 2761 2762
		/* may need to reset tstamp_enabled */
		if (is_cgroup_event(event))
			perf_cgroup_mark_enabled(event, ctx);

P
Peter Zijlstra 已提交
2763
		if (group_can_go_on(event, cpuctx, can_add_hw)) {
2764
			if (group_sched_in(event, cpuctx, ctx))
2765
				can_add_hw = 0;
P
Peter Zijlstra 已提交
2766
		}
T
Thomas Gleixner 已提交
2767
	}
2768 2769 2770 2771 2772
}

static void
ctx_sched_in(struct perf_event_context *ctx,
	     struct perf_cpu_context *cpuctx,
S
Stephane Eranian 已提交
2773 2774
	     enum event_type_t event_type,
	     struct task_struct *task)
2775
{
2776
	int is_active = ctx->is_active;
P
Peter Zijlstra 已提交
2777 2778 2779
	u64 now;

	lockdep_assert_held(&ctx->lock);
S
Stephane Eranian 已提交
2780

2781
	if (likely(!ctx->nr_events))
2782
		return;
2783

2784
	ctx->is_active |= (event_type | EVENT_TIME);
2785 2786 2787 2788 2789 2790 2791
	if (ctx->task) {
		if (!is_active)
			cpuctx->task_ctx = ctx;
		else
			WARN_ON_ONCE(cpuctx->task_ctx != ctx);
	}

2792 2793 2794 2795 2796 2797 2798 2799 2800
	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);
	}

2801 2802 2803 2804
	/*
	 * First go through the list and put on any pinned groups
	 * in order to give them the best chance of going on.
	 */
2805
	if (is_active & EVENT_PINNED)
2806
		ctx_pinned_sched_in(ctx, cpuctx);
2807 2808

	/* Then walk through the lower prio flexible groups */
2809
	if (is_active & EVENT_FLEXIBLE)
2810
		ctx_flexible_sched_in(ctx, cpuctx);
2811 2812
}

2813
static void cpu_ctx_sched_in(struct perf_cpu_context *cpuctx,
S
Stephane Eranian 已提交
2814 2815
			     enum event_type_t event_type,
			     struct task_struct *task)
2816 2817 2818
{
	struct perf_event_context *ctx = &cpuctx->ctx;

S
Stephane Eranian 已提交
2819
	ctx_sched_in(ctx, cpuctx, event_type, task);
2820 2821
}

S
Stephane Eranian 已提交
2822 2823
static void perf_event_context_sched_in(struct perf_event_context *ctx,
					struct task_struct *task)
2824
{
P
Peter Zijlstra 已提交
2825
	struct perf_cpu_context *cpuctx;
2826

P
Peter Zijlstra 已提交
2827
	cpuctx = __get_cpu_context(ctx);
2828 2829 2830
	if (cpuctx->task_ctx == ctx)
		return;

2831
	perf_ctx_lock(cpuctx, ctx);
P
Peter Zijlstra 已提交
2832
	perf_pmu_disable(ctx->pmu);
2833 2834 2835 2836 2837 2838
	/*
	 * 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);
2839
	perf_event_sched_in(cpuctx, ctx, task);
2840 2841
	perf_pmu_enable(ctx->pmu);
	perf_ctx_unlock(cpuctx, ctx);
2842 2843
}

P
Peter Zijlstra 已提交
2844 2845 2846 2847 2848 2849 2850 2851 2852 2853 2854
/*
 * 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.
 */
2855 2856
void __perf_event_task_sched_in(struct task_struct *prev,
				struct task_struct *task)
P
Peter Zijlstra 已提交
2857 2858 2859 2860
{
	struct perf_event_context *ctx;
	int ctxn;

2861 2862 2863 2864 2865 2866 2867 2868 2869 2870
	/*
	 * 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
2871 2872 2873 2874 2875
	for_each_task_context_nr(ctxn) {
		ctx = task->perf_event_ctxp[ctxn];
		if (likely(!ctx))
			continue;

S
Stephane Eranian 已提交
2876
		perf_event_context_sched_in(ctx, task);
P
Peter Zijlstra 已提交
2877
	}
2878

2879 2880 2881
	if (atomic_read(&nr_switch_events))
		perf_event_switch(task, prev, true);

2882 2883
	if (__this_cpu_read(perf_sched_cb_usages))
		perf_pmu_sched_task(prev, task, true);
2884 2885
}

2886 2887 2888 2889 2890 2891 2892 2893 2894 2895 2896 2897 2898 2899 2900 2901 2902 2903 2904 2905 2906 2907 2908 2909 2910 2911 2912
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.
	 */
2913
#define REDUCE_FLS(a, b)		\
2914 2915 2916 2917 2918 2919 2920 2921 2922 2923 2924 2925 2926 2927 2928 2929 2930 2931 2932 2933 2934 2935 2936 2937 2938 2939 2940 2941 2942 2943 2944 2945 2946 2947 2948 2949 2950 2951 2952
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;
	}

2953 2954 2955
	if (!divisor)
		return dividend;

2956 2957 2958
	return div64_u64(dividend, divisor);
}

2959 2960 2961
static DEFINE_PER_CPU(int, perf_throttled_count);
static DEFINE_PER_CPU(u64, perf_throttled_seq);

2962
static void perf_adjust_period(struct perf_event *event, u64 nsec, u64 count, bool disable)
2963
{
2964
	struct hw_perf_event *hwc = &event->hw;
2965
	s64 period, sample_period;
2966 2967
	s64 delta;

2968
	period = perf_calculate_period(event, nsec, count);
2969 2970 2971 2972 2973 2974 2975 2976 2977 2978

	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;
2979

2980
	if (local64_read(&hwc->period_left) > 8*sample_period) {
2981 2982 2983
		if (disable)
			event->pmu->stop(event, PERF_EF_UPDATE);

2984
		local64_set(&hwc->period_left, 0);
2985 2986 2987

		if (disable)
			event->pmu->start(event, PERF_EF_RELOAD);
2988
	}
2989 2990
}

2991 2992 2993 2994 2995 2996 2997
/*
 * 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)
2998
{
2999 3000
	struct perf_event *event;
	struct hw_perf_event *hwc;
3001
	u64 now, period = TICK_NSEC;
3002
	s64 delta;
3003

3004 3005 3006 3007 3008 3009
	/*
	 * 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))
3010 3011
		return;

3012
	raw_spin_lock(&ctx->lock);
3013
	perf_pmu_disable(ctx->pmu);
3014

3015
	list_for_each_entry_rcu(event, &ctx->event_list, event_entry) {
3016
		if (event->state != PERF_EVENT_STATE_ACTIVE)
3017 3018
			continue;

3019
		if (!event_filter_match(event))
3020 3021
			continue;

3022 3023
		perf_pmu_disable(event->pmu);

3024
		hwc = &event->hw;
3025

3026
		if (hwc->interrupts == MAX_INTERRUPTS) {
3027
			hwc->interrupts = 0;
3028
			perf_log_throttle(event, 1);
P
Peter Zijlstra 已提交
3029
			event->pmu->start(event, 0);
3030 3031
		}

3032
		if (!event->attr.freq || !event->attr.sample_freq)
3033
			goto next;
3034

3035 3036 3037 3038 3039
		/*
		 * stop the event and update event->count
		 */
		event->pmu->stop(event, PERF_EF_UPDATE);

3040
		now = local64_read(&event->count);
3041 3042
		delta = now - hwc->freq_count_stamp;
		hwc->freq_count_stamp = now;
3043

3044 3045 3046
		/*
		 * restart the event
		 * reload only if value has changed
3047 3048 3049
		 * we have stopped the event so tell that
		 * to perf_adjust_period() to avoid stopping it
		 * twice.
3050
		 */
3051
		if (delta > 0)
3052
			perf_adjust_period(event, period, delta, false);
3053 3054

		event->pmu->start(event, delta > 0 ? PERF_EF_RELOAD : 0);
3055 3056
	next:
		perf_pmu_enable(event->pmu);
3057
	}
3058

3059
	perf_pmu_enable(ctx->pmu);
3060
	raw_spin_unlock(&ctx->lock);
3061 3062
}

3063
/*
3064
 * Round-robin a context's events:
3065
 */
3066
static void rotate_ctx(struct perf_event_context *ctx)
T
Thomas Gleixner 已提交
3067
{
3068 3069 3070 3071 3072 3073
	/*
	 * 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);
3074 3075
}

3076
static int perf_rotate_context(struct perf_cpu_context *cpuctx)
3077
{
P
Peter Zijlstra 已提交
3078
	struct perf_event_context *ctx = NULL;
3079
	int rotate = 0;
3080

3081 3082 3083 3084
	if (cpuctx->ctx.nr_events) {
		if (cpuctx->ctx.nr_events != cpuctx->ctx.nr_active)
			rotate = 1;
	}
3085

P
Peter Zijlstra 已提交
3086
	ctx = cpuctx->task_ctx;
3087 3088 3089 3090
	if (ctx && ctx->nr_events) {
		if (ctx->nr_events != ctx->nr_active)
			rotate = 1;
	}
3091

3092
	if (!rotate)
3093 3094
		goto done;

3095
	perf_ctx_lock(cpuctx, cpuctx->task_ctx);
P
Peter Zijlstra 已提交
3096
	perf_pmu_disable(cpuctx->ctx.pmu);
3097

3098 3099 3100
	cpu_ctx_sched_out(cpuctx, EVENT_FLEXIBLE);
	if (ctx)
		ctx_sched_out(ctx, cpuctx, EVENT_FLEXIBLE);
T
Thomas Gleixner 已提交
3101

3102 3103 3104
	rotate_ctx(&cpuctx->ctx);
	if (ctx)
		rotate_ctx(ctx);
3105

3106
	perf_event_sched_in(cpuctx, ctx, current);
3107

3108 3109
	perf_pmu_enable(cpuctx->ctx.pmu);
	perf_ctx_unlock(cpuctx, cpuctx->task_ctx);
3110
done:
3111 3112

	return rotate;
3113 3114
}

3115 3116 3117
#ifdef CONFIG_NO_HZ_FULL
bool perf_event_can_stop_tick(void)
{
3118
	if (atomic_read(&nr_freq_events) ||
3119
	    __this_cpu_read(perf_throttled_count))
3120
		return false;
3121 3122
	else
		return true;
3123 3124 3125
}
#endif

3126 3127
void perf_event_task_tick(void)
{
3128 3129
	struct list_head *head = this_cpu_ptr(&active_ctx_list);
	struct perf_event_context *ctx, *tmp;
3130
	int throttled;
3131

3132 3133
	WARN_ON(!irqs_disabled());

3134 3135 3136
	__this_cpu_inc(perf_throttled_seq);
	throttled = __this_cpu_xchg(perf_throttled_count, 0);

3137
	list_for_each_entry_safe(ctx, tmp, head, active_ctx_list)
3138
		perf_adjust_freq_unthr_context(ctx, throttled);
T
Thomas Gleixner 已提交
3139 3140
}

3141 3142 3143 3144 3145 3146 3147 3148 3149 3150
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;

3151
	__perf_event_mark_enabled(event);
3152 3153 3154 3155

	return 1;
}

3156
/*
3157
 * Enable all of a task's events that have been marked enable-on-exec.
3158 3159
 * This expects task == current.
 */
3160
static void perf_event_enable_on_exec(int ctxn)
3161
{
3162
	struct perf_event_context *ctx, *clone_ctx = NULL;
3163
	struct perf_cpu_context *cpuctx;
3164
	struct perf_event *event;
3165 3166 3167 3168
	unsigned long flags;
	int enabled = 0;

	local_irq_save(flags);
3169
	ctx = current->perf_event_ctxp[ctxn];
3170
	if (!ctx || !ctx->nr_events)
3171 3172
		goto out;

3173 3174
	cpuctx = __get_cpu_context(ctx);
	perf_ctx_lock(cpuctx, ctx);
3175
	ctx_sched_out(ctx, cpuctx, EVENT_TIME);
3176 3177
	list_for_each_entry(event, &ctx->event_list, event_entry)
		enabled |= event_enable_on_exec(event, ctx);
3178 3179

	/*
3180
	 * Unclone and reschedule this context if we enabled any event.
3181
	 */
3182
	if (enabled) {
3183
		clone_ctx = unclone_ctx(ctx);
3184 3185 3186
		ctx_resched(cpuctx, ctx);
	}
	perf_ctx_unlock(cpuctx, ctx);
3187

P
Peter Zijlstra 已提交
3188
out:
3189
	local_irq_restore(flags);
3190 3191 3192

	if (clone_ctx)
		put_ctx(clone_ctx);
3193 3194
}

3195 3196 3197 3198 3199
void perf_event_exec(void)
{
	int ctxn;

	rcu_read_lock();
3200 3201
	for_each_task_context_nr(ctxn)
		perf_event_enable_on_exec(ctxn);
3202 3203 3204
	rcu_read_unlock();
}

3205 3206 3207
struct perf_read_data {
	struct perf_event *event;
	bool group;
3208
	int ret;
3209 3210
};

T
Thomas Gleixner 已提交
3211
/*
3212
 * Cross CPU call to read the hardware event
T
Thomas Gleixner 已提交
3213
 */
3214
static void __perf_event_read(void *info)
T
Thomas Gleixner 已提交
3215
{
3216 3217
	struct perf_read_data *data = info;
	struct perf_event *sub, *event = data->event;
3218
	struct perf_event_context *ctx = event->ctx;
P
Peter Zijlstra 已提交
3219
	struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
3220
	struct pmu *pmu = event->pmu;
I
Ingo Molnar 已提交
3221

3222 3223 3224 3225
	/*
	 * 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
3226 3227
	 * event->count would have been updated to a recent sample
	 * when the event was scheduled out.
3228 3229 3230 3231
	 */
	if (ctx->task && cpuctx->task_ctx != ctx)
		return;

3232
	raw_spin_lock(&ctx->lock);
S
Stephane Eranian 已提交
3233
	if (ctx->is_active) {
3234
		update_context_time(ctx);
S
Stephane Eranian 已提交
3235 3236
		update_cgrp_time_from_event(event);
	}
3237

3238
	update_event_times(event);
3239 3240
	if (event->state != PERF_EVENT_STATE_ACTIVE)
		goto unlock;
3241

3242 3243 3244
	if (!data->group) {
		pmu->read(event);
		data->ret = 0;
3245
		goto unlock;
3246 3247 3248 3249 3250
	}

	pmu->start_txn(pmu, PERF_PMU_TXN_READ);

	pmu->read(event);
3251 3252 3253

	list_for_each_entry(sub, &event->sibling_list, group_entry) {
		update_event_times(sub);
3254 3255 3256 3257 3258
		if (sub->state == PERF_EVENT_STATE_ACTIVE) {
			/*
			 * Use sibling's PMU rather than @event's since
			 * sibling could be on different (eg: software) PMU.
			 */
3259
			sub->pmu->read(sub);
3260
		}
3261
	}
3262 3263

	data->ret = pmu->commit_txn(pmu);
3264 3265

unlock:
3266
	raw_spin_unlock(&ctx->lock);
T
Thomas Gleixner 已提交
3267 3268
}

P
Peter Zijlstra 已提交
3269 3270
static inline u64 perf_event_count(struct perf_event *event)
{
3271 3272 3273 3274
	if (event->pmu->count)
		return event->pmu->count(event);

	return __perf_event_count(event);
P
Peter Zijlstra 已提交
3275 3276
}

3277 3278 3279 3280 3281 3282 3283 3284 3285 3286 3287 3288 3289 3290 3291 3292 3293 3294 3295 3296 3297 3298 3299 3300 3301 3302 3303 3304 3305 3306 3307 3308 3309 3310 3311 3312 3313 3314 3315 3316 3317 3318 3319 3320 3321 3322 3323 3324 3325 3326 3327 3328 3329
/*
 * 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;
}

3330
static int perf_event_read(struct perf_event *event, bool group)
T
Thomas Gleixner 已提交
3331
{
3332 3333
	int ret = 0;

T
Thomas Gleixner 已提交
3334
	/*
3335 3336
	 * If event is enabled and currently active on a CPU, update the
	 * value in the event structure:
T
Thomas Gleixner 已提交
3337
	 */
3338
	if (event->state == PERF_EVENT_STATE_ACTIVE) {
3339 3340 3341
		struct perf_read_data data = {
			.event = event,
			.group = group,
3342
			.ret = 0,
3343
		};
3344
		smp_call_function_single(event->oncpu,
3345
					 __perf_event_read, &data, 1);
3346
		ret = data.ret;
3347
	} else if (event->state == PERF_EVENT_STATE_INACTIVE) {
P
Peter Zijlstra 已提交
3348 3349 3350
		struct perf_event_context *ctx = event->ctx;
		unsigned long flags;

3351
		raw_spin_lock_irqsave(&ctx->lock, flags);
3352 3353 3354 3355 3356
		/*
		 * 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
3357
		if (ctx->is_active) {
3358
			update_context_time(ctx);
S
Stephane Eranian 已提交
3359 3360
			update_cgrp_time_from_event(event);
		}
3361 3362 3363 3364
		if (group)
			update_group_times(event);
		else
			update_event_times(event);
3365
		raw_spin_unlock_irqrestore(&ctx->lock, flags);
T
Thomas Gleixner 已提交
3366
	}
3367 3368

	return ret;
T
Thomas Gleixner 已提交
3369 3370
}

3371
/*
3372
 * Initialize the perf_event context in a task_struct:
3373
 */
3374
static void __perf_event_init_context(struct perf_event_context *ctx)
3375
{
3376
	raw_spin_lock_init(&ctx->lock);
3377
	mutex_init(&ctx->mutex);
3378
	INIT_LIST_HEAD(&ctx->active_ctx_list);
3379 3380
	INIT_LIST_HEAD(&ctx->pinned_groups);
	INIT_LIST_HEAD(&ctx->flexible_groups);
3381 3382
	INIT_LIST_HEAD(&ctx->event_list);
	atomic_set(&ctx->refcount, 1);
3383 3384 3385 3386 3387 3388 3389 3390 3391 3392 3393 3394 3395 3396 3397
}

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
3398
	}
3399 3400 3401
	ctx->pmu = pmu;

	return ctx;
3402 3403
}

3404 3405 3406 3407 3408
static struct task_struct *
find_lively_task_by_vpid(pid_t vpid)
{
	struct task_struct *task;
	int err;
T
Thomas Gleixner 已提交
3409 3410

	rcu_read_lock();
3411
	if (!vpid)
T
Thomas Gleixner 已提交
3412 3413
		task = current;
	else
3414
		task = find_task_by_vpid(vpid);
T
Thomas Gleixner 已提交
3415 3416 3417 3418 3419 3420 3421 3422
	if (task)
		get_task_struct(task);
	rcu_read_unlock();

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

	/* Reuse ptrace permission checks for now. */
3423
	err = -EACCES;
3424
	if (!ptrace_may_access(task, PTRACE_MODE_READ_REALCREDS))
3425 3426
		goto errout;

3427 3428 3429 3430 3431 3432 3433
	return task;
errout:
	put_task_struct(task);
	return ERR_PTR(err);

}

3434 3435 3436
/*
 * Returns a matching context with refcount and pincount.
 */
P
Peter Zijlstra 已提交
3437
static struct perf_event_context *
3438 3439
find_get_context(struct pmu *pmu, struct task_struct *task,
		struct perf_event *event)
T
Thomas Gleixner 已提交
3440
{
3441
	struct perf_event_context *ctx, *clone_ctx = NULL;
3442
	struct perf_cpu_context *cpuctx;
3443
	void *task_ctx_data = NULL;
3444
	unsigned long flags;
P
Peter Zijlstra 已提交
3445
	int ctxn, err;
3446
	int cpu = event->cpu;
T
Thomas Gleixner 已提交
3447

3448
	if (!task) {
3449
		/* Must be root to operate on a CPU event: */
3450
		if (perf_paranoid_cpu() && !capable(CAP_SYS_ADMIN))
T
Thomas Gleixner 已提交
3451 3452 3453
			return ERR_PTR(-EACCES);

		/*
3454
		 * We could be clever and allow to attach a event to an
T
Thomas Gleixner 已提交
3455 3456 3457
		 * offline CPU and activate it when the CPU comes up, but
		 * that's for later.
		 */
3458
		if (!cpu_online(cpu))
T
Thomas Gleixner 已提交
3459 3460
			return ERR_PTR(-ENODEV);

P
Peter Zijlstra 已提交
3461
		cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
T
Thomas Gleixner 已提交
3462
		ctx = &cpuctx->ctx;
3463
		get_ctx(ctx);
3464
		++ctx->pin_count;
T
Thomas Gleixner 已提交
3465 3466 3467 3468

		return ctx;
	}

P
Peter Zijlstra 已提交
3469 3470 3471 3472 3473
	err = -EINVAL;
	ctxn = pmu->task_ctx_nr;
	if (ctxn < 0)
		goto errout;

3474 3475 3476 3477 3478 3479 3480 3481
	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
3482
retry:
P
Peter Zijlstra 已提交
3483
	ctx = perf_lock_task_context(task, ctxn, &flags);
3484
	if (ctx) {
3485
		clone_ctx = unclone_ctx(ctx);
3486
		++ctx->pin_count;
3487 3488 3489 3490 3491

		if (task_ctx_data && !ctx->task_ctx_data) {
			ctx->task_ctx_data = task_ctx_data;
			task_ctx_data = NULL;
		}
3492
		raw_spin_unlock_irqrestore(&ctx->lock, flags);
3493 3494 3495

		if (clone_ctx)
			put_ctx(clone_ctx);
3496
	} else {
3497
		ctx = alloc_perf_context(pmu, task);
3498 3499 3500
		err = -ENOMEM;
		if (!ctx)
			goto errout;
3501

3502 3503 3504 3505 3506
		if (task_ctx_data) {
			ctx->task_ctx_data = task_ctx_data;
			task_ctx_data = NULL;
		}

3507 3508 3509 3510 3511 3512 3513 3514 3515 3516
		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;
3517
		else {
3518
			get_ctx(ctx);
3519
			++ctx->pin_count;
3520
			rcu_assign_pointer(task->perf_event_ctxp[ctxn], ctx);
3521
		}
3522 3523 3524
		mutex_unlock(&task->perf_event_mutex);

		if (unlikely(err)) {
3525
			put_ctx(ctx);
3526 3527 3528 3529

			if (err == -EAGAIN)
				goto retry;
			goto errout;
3530 3531 3532
		}
	}

3533
	kfree(task_ctx_data);
T
Thomas Gleixner 已提交
3534
	return ctx;
3535

P
Peter Zijlstra 已提交
3536
errout:
3537
	kfree(task_ctx_data);
3538
	return ERR_PTR(err);
T
Thomas Gleixner 已提交
3539 3540
}

L
Li Zefan 已提交
3541
static void perf_event_free_filter(struct perf_event *event);
3542
static void perf_event_free_bpf_prog(struct perf_event *event);
L
Li Zefan 已提交
3543

3544
static void free_event_rcu(struct rcu_head *head)
P
Peter Zijlstra 已提交
3545
{
3546
	struct perf_event *event;
P
Peter Zijlstra 已提交
3547

3548 3549 3550
	event = container_of(head, struct perf_event, rcu_head);
	if (event->ns)
		put_pid_ns(event->ns);
L
Li Zefan 已提交
3551
	perf_event_free_filter(event);
3552
	kfree(event);
P
Peter Zijlstra 已提交
3553 3554
}

3555 3556
static void ring_buffer_attach(struct perf_event *event,
			       struct ring_buffer *rb);
3557

3558
static void unaccount_event_cpu(struct perf_event *event, int cpu)
3559
{
3560 3561 3562 3563 3564 3565
	if (event->parent)
		return;

	if (is_cgroup_event(event))
		atomic_dec(&per_cpu(perf_cgroup_events, cpu));
}
3566

3567 3568
static void unaccount_event(struct perf_event *event)
{
3569 3570
	bool dec = false;

3571 3572 3573 3574
	if (event->parent)
		return;

	if (event->attach_state & PERF_ATTACH_TASK)
3575
		dec = true;
3576 3577 3578 3579 3580 3581
	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);
3582 3583
	if (event->attr.freq)
		atomic_dec(&nr_freq_events);
3584
	if (event->attr.context_switch) {
3585
		dec = true;
3586 3587
		atomic_dec(&nr_switch_events);
	}
3588
	if (is_cgroup_event(event))
3589
		dec = true;
3590
	if (has_branch_stack(event))
3591 3592
		dec = true;

3593 3594 3595 3596
	if (dec) {
		if (!atomic_add_unless(&perf_sched_count, -1, 1))
			schedule_delayed_work(&perf_sched_work, HZ);
	}
3597 3598 3599

	unaccount_event_cpu(event, event->cpu);
}
3600

3601 3602 3603 3604 3605 3606 3607 3608
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);
}

3609 3610 3611 3612 3613 3614 3615 3616 3617 3618
/*
 * 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
3619
 * _free_event()), the latter -- before the first perf_install_in_context().
3620 3621 3622 3623 3624 3625 3626 3627 3628 3629 3630 3631 3632 3633 3634 3635 3636 3637 3638 3639 3640 3641 3642 3643 3644 3645 3646 3647 3648 3649 3650 3651 3652 3653 3654 3655 3656 3657 3658 3659 3660 3661 3662 3663 3664 3665 3666 3667 3668 3669 3670 3671 3672 3673 3674 3675 3676 3677 3678 3679 3680 3681 3682 3683 3684 3685 3686 3687 3688 3689 3690 3691 3692 3693
 */
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;
}

P
Peter Zijlstra 已提交
3694
static void _free_event(struct perf_event *event)
3695
{
3696
	irq_work_sync(&event->pending);
3697

3698
	unaccount_event(event);
3699

3700
	if (event->rb) {
3701 3702 3703 3704 3705 3706 3707
		/*
		 * 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);
3708
		ring_buffer_attach(event, NULL);
3709
		mutex_unlock(&event->mmap_mutex);
3710 3711
	}

S
Stephane Eranian 已提交
3712 3713 3714
	if (is_cgroup_event(event))
		perf_detach_cgroup(event);

P
Peter Zijlstra 已提交
3715 3716 3717 3718 3719 3720 3721 3722 3723 3724 3725 3726 3727 3728 3729 3730 3731 3732 3733
	if (!event->parent) {
		if (event->attr.sample_type & PERF_SAMPLE_CALLCHAIN)
			put_callchain_buffers();
	}

	perf_event_free_bpf_prog(event);

	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);
3734 3735
}

P
Peter Zijlstra 已提交
3736 3737 3738 3739 3740
/*
 * 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
3741
{
P
Peter Zijlstra 已提交
3742 3743 3744 3745 3746 3747
	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
3748

P
Peter Zijlstra 已提交
3749
	_free_event(event);
T
Thomas Gleixner 已提交
3750 3751
}

3752
/*
3753
 * Remove user event from the owner task.
3754
 */
3755
static void perf_remove_from_owner(struct perf_event *event)
3756
{
P
Peter Zijlstra 已提交
3757
	struct task_struct *owner;
3758

P
Peter Zijlstra 已提交
3759 3760
	rcu_read_lock();
	/*
3761 3762 3763
	 * 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
3764 3765
	 * owner->perf_event_mutex.
	 */
3766
	owner = lockless_dereference(event->owner);
P
Peter Zijlstra 已提交
3767 3768 3769 3770 3771 3772 3773 3774 3775 3776 3777
	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
3778 3779 3780 3781 3782 3783 3784 3785 3786 3787
		/*
		 * 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
3788 3789 3790 3791 3792 3793
		/*
		 * 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.
		 */
3794
		if (event->owner) {
P
Peter Zijlstra 已提交
3795
			list_del_init(&event->owner_entry);
3796 3797
			smp_store_release(&event->owner, NULL);
		}
P
Peter Zijlstra 已提交
3798 3799 3800
		mutex_unlock(&owner->perf_event_mutex);
		put_task_struct(owner);
	}
3801 3802 3803 3804 3805 3806 3807
}

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

3808 3809 3810 3811 3812 3813 3814 3815 3816 3817
	_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)
{
3818
	struct perf_event_context *ctx = event->ctx;
3819 3820
	struct perf_event *child, *tmp;

3821 3822 3823 3824 3825 3826 3827 3828 3829 3830
	/*
	 * 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;
	}

3831 3832
	if (!is_kernel_event(event))
		perf_remove_from_owner(event);
P
Peter Zijlstra 已提交
3833

3834
	ctx = perf_event_ctx_lock(event);
P
Peter Zijlstra 已提交
3835
	WARN_ON_ONCE(ctx->parent_ctx);
P
Peter Zijlstra 已提交
3836
	perf_remove_from_context(event, DETACH_GROUP);
P
Peter Zijlstra 已提交
3837

P
Peter Zijlstra 已提交
3838
	raw_spin_lock_irq(&ctx->lock);
P
Peter Zijlstra 已提交
3839
	/*
P
Peter Zijlstra 已提交
3840 3841
	 * Mark this even as STATE_DEAD, there is no external reference to it
	 * anymore.
P
Peter Zijlstra 已提交
3842
	 *
P
Peter Zijlstra 已提交
3843 3844 3845
	 * 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
3846
	 *
3847 3848
	 * Thus this guarantees that we will in fact observe and kill _ALL_
	 * child events.
P
Peter Zijlstra 已提交
3849
	 */
P
Peter Zijlstra 已提交
3850 3851 3852 3853
	event->state = PERF_EVENT_STATE_DEAD;
	raw_spin_unlock_irq(&ctx->lock);

	perf_event_ctx_unlock(event, ctx);
P
Peter Zijlstra 已提交
3854

3855 3856 3857
again:
	mutex_lock(&event->child_mutex);
	list_for_each_entry(child, &event->child_list, child_list) {
3858

3859 3860 3861 3862 3863 3864 3865 3866 3867 3868 3869 3870 3871 3872 3873 3874 3875 3876 3877 3878 3879 3880 3881 3882 3883 3884 3885 3886 3887 3888 3889 3890 3891 3892 3893 3894 3895 3896 3897 3898 3899 3900 3901 3902 3903 3904 3905 3906 3907
		/*
		 * 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);

3908 3909
no_ctx:
	put_event(event); /* Must be the 'last' reference */
P
Peter Zijlstra 已提交
3910 3911 3912 3913
	return 0;
}
EXPORT_SYMBOL_GPL(perf_event_release_kernel);

3914 3915 3916
/*
 * Called when the last reference to the file is gone.
 */
3917 3918
static int perf_release(struct inode *inode, struct file *file)
{
3919
	perf_event_release_kernel(file->private_data);
3920
	return 0;
3921 3922
}

3923
u64 perf_event_read_value(struct perf_event *event, u64 *enabled, u64 *running)
3924
{
3925
	struct perf_event *child;
3926 3927
	u64 total = 0;

3928 3929 3930
	*enabled = 0;
	*running = 0;

3931
	mutex_lock(&event->child_mutex);
3932

3933
	(void)perf_event_read(event, false);
3934 3935
	total += perf_event_count(event);

3936 3937 3938 3939 3940 3941
	*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) {
3942
		(void)perf_event_read(child, false);
3943
		total += perf_event_count(child);
3944 3945 3946
		*enabled += child->total_time_enabled;
		*running += child->total_time_running;
	}
3947
	mutex_unlock(&event->child_mutex);
3948 3949 3950

	return total;
}
3951
EXPORT_SYMBOL_GPL(perf_event_read_value);
3952

3953
static int __perf_read_group_add(struct perf_event *leader,
3954
					u64 read_format, u64 *values)
3955
{
3956 3957
	struct perf_event *sub;
	int n = 1; /* skip @nr */
3958
	int ret;
P
Peter Zijlstra 已提交
3959

3960 3961 3962
	ret = perf_event_read(leader, true);
	if (ret)
		return ret;
3963

3964 3965 3966 3967 3968 3969 3970 3971 3972
	/*
	 * 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);
	}
3973

3974 3975 3976 3977 3978 3979 3980 3981 3982
	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);
3983 3984
	if (read_format & PERF_FORMAT_ID)
		values[n++] = primary_event_id(leader);
3985

3986 3987 3988 3989 3990
	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);
	}
3991 3992

	return 0;
3993
}
3994

3995 3996 3997 3998 3999
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;
4000
	int ret;
4001
	u64 *values;
4002

4003
	lockdep_assert_held(&ctx->mutex);
4004

4005 4006 4007
	values = kzalloc(event->read_size, GFP_KERNEL);
	if (!values)
		return -ENOMEM;
4008

4009 4010 4011 4012 4013 4014 4015
	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);
4016

4017 4018 4019 4020 4021 4022 4023 4024 4025
	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;
	}
4026

4027
	mutex_unlock(&leader->child_mutex);
4028

4029
	ret = event->read_size;
4030 4031
	if (copy_to_user(buf, values, event->read_size))
		ret = -EFAULT;
4032
	goto out;
4033

4034 4035 4036
unlock:
	mutex_unlock(&leader->child_mutex);
out:
4037
	kfree(values);
4038
	return ret;
4039 4040
}

4041
static int perf_read_one(struct perf_event *event,
4042 4043
				 u64 read_format, char __user *buf)
{
4044
	u64 enabled, running;
4045 4046 4047
	u64 values[4];
	int n = 0;

4048 4049 4050 4051 4052
	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;
4053
	if (read_format & PERF_FORMAT_ID)
4054
		values[n++] = primary_event_id(event);
4055 4056 4057 4058 4059 4060 4061

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

	return n * sizeof(u64);
}

4062 4063 4064 4065
static bool is_event_hup(struct perf_event *event)
{
	bool no_children;

P
Peter Zijlstra 已提交
4066
	if (event->state > PERF_EVENT_STATE_EXIT)
4067 4068 4069 4070 4071 4072 4073 4074
		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
4075
/*
4076
 * Read the performance event - simple non blocking version for now
T
Thomas Gleixner 已提交
4077 4078
 */
static ssize_t
4079
__perf_read(struct perf_event *event, char __user *buf, size_t count)
T
Thomas Gleixner 已提交
4080
{
4081
	u64 read_format = event->attr.read_format;
4082
	int ret;
T
Thomas Gleixner 已提交
4083

4084
	/*
4085
	 * Return end-of-file for a read on a event that is in
4086 4087 4088
	 * error state (i.e. because it was pinned but it couldn't be
	 * scheduled on to the CPU at some point).
	 */
4089
	if (event->state == PERF_EVENT_STATE_ERROR)
4090 4091
		return 0;

4092
	if (count < event->read_size)
4093 4094
		return -ENOSPC;

4095
	WARN_ON_ONCE(event->ctx->parent_ctx);
4096
	if (read_format & PERF_FORMAT_GROUP)
4097
		ret = perf_read_group(event, read_format, buf);
4098
	else
4099
		ret = perf_read_one(event, read_format, buf);
T
Thomas Gleixner 已提交
4100

4101
	return ret;
T
Thomas Gleixner 已提交
4102 4103 4104 4105 4106
}

static ssize_t
perf_read(struct file *file, char __user *buf, size_t count, loff_t *ppos)
{
4107
	struct perf_event *event = file->private_data;
P
Peter Zijlstra 已提交
4108 4109
	struct perf_event_context *ctx;
	int ret;
T
Thomas Gleixner 已提交
4110

P
Peter Zijlstra 已提交
4111
	ctx = perf_event_ctx_lock(event);
4112
	ret = __perf_read(event, buf, count);
P
Peter Zijlstra 已提交
4113 4114 4115
	perf_event_ctx_unlock(event, ctx);

	return ret;
T
Thomas Gleixner 已提交
4116 4117 4118 4119
}

static unsigned int perf_poll(struct file *file, poll_table *wait)
{
4120
	struct perf_event *event = file->private_data;
4121
	struct ring_buffer *rb;
4122
	unsigned int events = POLLHUP;
P
Peter Zijlstra 已提交
4123

4124
	poll_wait(file, &event->waitq, wait);
4125

4126
	if (is_event_hup(event))
4127
		return events;
P
Peter Zijlstra 已提交
4128

4129
	/*
4130 4131
	 * Pin the event->rb by taking event->mmap_mutex; otherwise
	 * perf_event_set_output() can swizzle our rb and make us miss wakeups.
4132 4133
	 */
	mutex_lock(&event->mmap_mutex);
4134 4135
	rb = event->rb;
	if (rb)
4136
		events = atomic_xchg(&rb->poll, 0);
4137
	mutex_unlock(&event->mmap_mutex);
T
Thomas Gleixner 已提交
4138 4139 4140
	return events;
}

P
Peter Zijlstra 已提交
4141
static void _perf_event_reset(struct perf_event *event)
4142
{
4143
	(void)perf_event_read(event, false);
4144
	local64_set(&event->count, 0);
4145
	perf_event_update_userpage(event);
P
Peter Zijlstra 已提交
4146 4147
}

4148
/*
4149 4150
 * Holding the top-level event's child_mutex means that any
 * descendant process that has inherited this event will block
4151
 * in perf_event_exit_event() if it goes to exit, thus satisfying the
4152
 * task existence requirements of perf_event_enable/disable.
4153
 */
4154 4155
static void perf_event_for_each_child(struct perf_event *event,
					void (*func)(struct perf_event *))
P
Peter Zijlstra 已提交
4156
{
4157
	struct perf_event *child;
P
Peter Zijlstra 已提交
4158

4159
	WARN_ON_ONCE(event->ctx->parent_ctx);
P
Peter Zijlstra 已提交
4160

4161 4162 4163
	mutex_lock(&event->child_mutex);
	func(event);
	list_for_each_entry(child, &event->child_list, child_list)
P
Peter Zijlstra 已提交
4164
		func(child);
4165
	mutex_unlock(&event->child_mutex);
P
Peter Zijlstra 已提交
4166 4167
}

4168 4169
static void perf_event_for_each(struct perf_event *event,
				  void (*func)(struct perf_event *))
P
Peter Zijlstra 已提交
4170
{
4171 4172
	struct perf_event_context *ctx = event->ctx;
	struct perf_event *sibling;
P
Peter Zijlstra 已提交
4173

P
Peter Zijlstra 已提交
4174 4175
	lockdep_assert_held(&ctx->mutex);

4176
	event = event->group_leader;
4177

4178 4179
	perf_event_for_each_child(event, func);
	list_for_each_entry(sibling, &event->sibling_list, group_entry)
4180
		perf_event_for_each_child(sibling, func);
4181 4182
}

4183 4184 4185 4186
static void __perf_event_period(struct perf_event *event,
				struct perf_cpu_context *cpuctx,
				struct perf_event_context *ctx,
				void *info)
4187
{
4188
	u64 value = *((u64 *)info);
4189
	bool active;
4190

4191 4192
	if (event->attr.freq) {
		event->attr.sample_freq = value;
4193
	} else {
4194 4195
		event->attr.sample_period = value;
		event->hw.sample_period = value;
4196
	}
4197 4198 4199 4200 4201 4202 4203 4204 4205 4206 4207 4208 4209

	active = (event->state == PERF_EVENT_STATE_ACTIVE);
	if (active) {
		perf_pmu_disable(ctx->pmu);
		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);
	}
4210 4211 4212 4213 4214 4215 4216 4217 4218 4219 4220 4221 4222 4223 4224 4225 4226 4227
}

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;

4228
	event_function_call(event, __perf_event_period, &value);
4229

4230
	return 0;
4231 4232
}

4233 4234
static const struct file_operations perf_fops;

4235
static inline int perf_fget_light(int fd, struct fd *p)
4236
{
4237 4238 4239
	struct fd f = fdget(fd);
	if (!f.file)
		return -EBADF;
4240

4241 4242 4243
	if (f.file->f_op != &perf_fops) {
		fdput(f);
		return -EBADF;
4244
	}
4245 4246
	*p = f;
	return 0;
4247 4248 4249 4250
}

static int perf_event_set_output(struct perf_event *event,
				 struct perf_event *output_event);
L
Li Zefan 已提交
4251
static int perf_event_set_filter(struct perf_event *event, void __user *arg);
4252
static int perf_event_set_bpf_prog(struct perf_event *event, u32 prog_fd);
4253

P
Peter Zijlstra 已提交
4254
static long _perf_ioctl(struct perf_event *event, unsigned int cmd, unsigned long arg)
4255
{
4256
	void (*func)(struct perf_event *);
P
Peter Zijlstra 已提交
4257
	u32 flags = arg;
4258 4259

	switch (cmd) {
4260
	case PERF_EVENT_IOC_ENABLE:
P
Peter Zijlstra 已提交
4261
		func = _perf_event_enable;
4262
		break;
4263
	case PERF_EVENT_IOC_DISABLE:
P
Peter Zijlstra 已提交
4264
		func = _perf_event_disable;
4265
		break;
4266
	case PERF_EVENT_IOC_RESET:
P
Peter Zijlstra 已提交
4267
		func = _perf_event_reset;
4268
		break;
P
Peter Zijlstra 已提交
4269

4270
	case PERF_EVENT_IOC_REFRESH:
P
Peter Zijlstra 已提交
4271
		return _perf_event_refresh(event, arg);
4272

4273 4274
	case PERF_EVENT_IOC_PERIOD:
		return perf_event_period(event, (u64 __user *)arg);
4275

4276 4277 4278 4279 4280 4281 4282 4283 4284
	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;
	}

4285
	case PERF_EVENT_IOC_SET_OUTPUT:
4286 4287 4288
	{
		int ret;
		if (arg != -1) {
4289 4290 4291 4292 4293 4294 4295 4296 4297 4298
			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);
4299 4300 4301
		}
		return ret;
	}
4302

L
Li Zefan 已提交
4303 4304 4305
	case PERF_EVENT_IOC_SET_FILTER:
		return perf_event_set_filter(event, (void __user *)arg);

4306 4307 4308
	case PERF_EVENT_IOC_SET_BPF:
		return perf_event_set_bpf_prog(event, arg);

4309
	default:
P
Peter Zijlstra 已提交
4310
		return -ENOTTY;
4311
	}
P
Peter Zijlstra 已提交
4312 4313

	if (flags & PERF_IOC_FLAG_GROUP)
4314
		perf_event_for_each(event, func);
P
Peter Zijlstra 已提交
4315
	else
4316
		perf_event_for_each_child(event, func);
P
Peter Zijlstra 已提交
4317 4318

	return 0;
4319 4320
}

P
Peter Zijlstra 已提交
4321 4322 4323 4324 4325 4326 4327 4328 4329 4330 4331 4332 4333
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
4334 4335 4336 4337 4338 4339 4340 4341 4342 4343 4344 4345 4346 4347 4348 4349 4350 4351 4352 4353
#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

4354
int perf_event_task_enable(void)
4355
{
P
Peter Zijlstra 已提交
4356
	struct perf_event_context *ctx;
4357
	struct perf_event *event;
4358

4359
	mutex_lock(&current->perf_event_mutex);
P
Peter Zijlstra 已提交
4360 4361 4362 4363 4364
	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);
	}
4365
	mutex_unlock(&current->perf_event_mutex);
4366 4367 4368 4369

	return 0;
}

4370
int perf_event_task_disable(void)
4371
{
P
Peter Zijlstra 已提交
4372
	struct perf_event_context *ctx;
4373
	struct perf_event *event;
4374

4375
	mutex_lock(&current->perf_event_mutex);
P
Peter Zijlstra 已提交
4376 4377 4378 4379 4380
	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);
	}
4381
	mutex_unlock(&current->perf_event_mutex);
4382 4383 4384 4385

	return 0;
}

4386
static int perf_event_index(struct perf_event *event)
4387
{
P
Peter Zijlstra 已提交
4388 4389 4390
	if (event->hw.state & PERF_HES_STOPPED)
		return 0;

4391
	if (event->state != PERF_EVENT_STATE_ACTIVE)
4392 4393
		return 0;

4394
	return event->pmu->event_idx(event);
4395 4396
}

4397
static void calc_timer_values(struct perf_event *event,
4398
				u64 *now,
4399 4400
				u64 *enabled,
				u64 *running)
4401
{
4402
	u64 ctx_time;
4403

4404 4405
	*now = perf_clock();
	ctx_time = event->shadow_ctx_time + *now;
4406 4407 4408 4409
	*enabled = ctx_time - event->tstamp_enabled;
	*running = ctx_time - event->tstamp_running;
}

4410 4411 4412 4413 4414 4415 4416 4417 4418 4419 4420 4421 4422 4423 4424
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);
4425 4426
	userpg->data_offset = PAGE_SIZE;
	userpg->data_size = perf_data_size(rb);
4427 4428 4429 4430 4431

unlock:
	rcu_read_unlock();
}

4432 4433
void __weak arch_perf_update_userpage(
	struct perf_event *event, struct perf_event_mmap_page *userpg, u64 now)
4434 4435 4436
{
}

4437 4438 4439 4440 4441
/*
 * 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.
 */
4442
void perf_event_update_userpage(struct perf_event *event)
4443
{
4444
	struct perf_event_mmap_page *userpg;
4445
	struct ring_buffer *rb;
4446
	u64 enabled, running, now;
4447 4448

	rcu_read_lock();
4449 4450 4451 4452
	rb = rcu_dereference(event->rb);
	if (!rb)
		goto unlock;

4453 4454 4455 4456 4457 4458 4459 4460 4461
	/*
	 * 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
	 */
4462
	calc_timer_values(event, &now, &enabled, &running);
4463

4464
	userpg = rb->user_page;
4465 4466 4467 4468 4469
	/*
	 * Disable preemption so as to not let the corresponding user-space
	 * spin too long if we get preempted.
	 */
	preempt_disable();
4470
	++userpg->lock;
4471
	barrier();
4472
	userpg->index = perf_event_index(event);
P
Peter Zijlstra 已提交
4473
	userpg->offset = perf_event_count(event);
4474
	if (userpg->index)
4475
		userpg->offset -= local64_read(&event->hw.prev_count);
4476

4477
	userpg->time_enabled = enabled +
4478
			atomic64_read(&event->child_total_time_enabled);
4479

4480
	userpg->time_running = running +
4481
			atomic64_read(&event->child_total_time_running);
4482

4483
	arch_perf_update_userpage(event, userpg, now);
4484

4485
	barrier();
4486
	++userpg->lock;
4487
	preempt_enable();
4488
unlock:
4489
	rcu_read_unlock();
4490 4491
}

4492 4493 4494
static int perf_mmap_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
{
	struct perf_event *event = vma->vm_file->private_data;
4495
	struct ring_buffer *rb;
4496 4497 4498 4499 4500 4501 4502 4503 4504
	int ret = VM_FAULT_SIGBUS;

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

	rcu_read_lock();
4505 4506
	rb = rcu_dereference(event->rb);
	if (!rb)
4507 4508 4509 4510 4511
		goto unlock;

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

4512
	vmf->page = perf_mmap_to_page(rb, vmf->pgoff);
4513 4514 4515 4516 4517 4518 4519 4520 4521 4522 4523 4524 4525 4526
	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;
}

4527 4528 4529
static void ring_buffer_attach(struct perf_event *event,
			       struct ring_buffer *rb)
{
4530
	struct ring_buffer *old_rb = NULL;
4531 4532
	unsigned long flags;

4533 4534 4535 4536 4537 4538
	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);
4539

4540 4541 4542 4543
		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);
4544

4545 4546
		event->rcu_batches = get_state_synchronize_rcu();
		event->rcu_pending = 1;
4547
	}
4548

4549
	if (rb) {
4550 4551 4552 4553 4554
		if (event->rcu_pending) {
			cond_synchronize_rcu(event->rcu_batches);
			event->rcu_pending = 0;
		}

4555 4556 4557 4558 4559 4560 4561 4562 4563 4564 4565 4566 4567 4568 4569 4570
		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);
	}
4571 4572 4573 4574 4575 4576 4577 4578
}

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

	rcu_read_lock();
	rb = rcu_dereference(event->rb);
4579 4580 4581 4582
	if (rb) {
		list_for_each_entry_rcu(event, &rb->event_list, rb_entry)
			wake_up_all(&event->waitq);
	}
4583 4584 4585
	rcu_read_unlock();
}

4586
struct ring_buffer *ring_buffer_get(struct perf_event *event)
4587
{
4588
	struct ring_buffer *rb;
4589

4590
	rcu_read_lock();
4591 4592 4593 4594
	rb = rcu_dereference(event->rb);
	if (rb) {
		if (!atomic_inc_not_zero(&rb->refcount))
			rb = NULL;
4595 4596 4597
	}
	rcu_read_unlock();

4598
	return rb;
4599 4600
}

4601
void ring_buffer_put(struct ring_buffer *rb)
4602
{
4603
	if (!atomic_dec_and_test(&rb->refcount))
4604
		return;
4605

4606
	WARN_ON_ONCE(!list_empty(&rb->event_list));
4607

4608
	call_rcu(&rb->rcu_head, rb_free_rcu);
4609 4610 4611 4612
}

static void perf_mmap_open(struct vm_area_struct *vma)
{
4613
	struct perf_event *event = vma->vm_file->private_data;
4614

4615
	atomic_inc(&event->mmap_count);
4616
	atomic_inc(&event->rb->mmap_count);
4617

4618 4619 4620
	if (vma->vm_pgoff)
		atomic_inc(&event->rb->aux_mmap_count);

4621 4622
	if (event->pmu->event_mapped)
		event->pmu->event_mapped(event);
4623 4624
}

4625 4626 4627 4628 4629 4630 4631 4632
/*
 * 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.
 */
4633 4634
static void perf_mmap_close(struct vm_area_struct *vma)
{
4635
	struct perf_event *event = vma->vm_file->private_data;
4636

4637
	struct ring_buffer *rb = ring_buffer_get(event);
4638 4639 4640
	struct user_struct *mmap_user = rb->mmap_user;
	int mmap_locked = rb->mmap_locked;
	unsigned long size = perf_data_size(rb);
4641

4642 4643 4644
	if (event->pmu->event_unmapped)
		event->pmu->event_unmapped(event);

4645 4646 4647 4648 4649 4650 4651 4652 4653 4654 4655 4656 4657 4658
	/*
	 * 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)) {
		atomic_long_sub(rb->aux_nr_pages, &mmap_user->locked_vm);
		vma->vm_mm->pinned_vm -= rb->aux_mmap_locked;

		rb_free_aux(rb);
		mutex_unlock(&event->mmap_mutex);
	}

4659 4660 4661
	atomic_dec(&rb->mmap_count);

	if (!atomic_dec_and_mutex_lock(&event->mmap_count, &event->mmap_mutex))
4662
		goto out_put;
4663

4664
	ring_buffer_attach(event, NULL);
4665 4666 4667
	mutex_unlock(&event->mmap_mutex);

	/* If there's still other mmap()s of this buffer, we're done. */
4668 4669
	if (atomic_read(&rb->mmap_count))
		goto out_put;
4670

4671 4672 4673 4674 4675 4676 4677 4678 4679 4680 4681 4682 4683 4684 4685 4686
	/*
	 * 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();
4687

4688 4689 4690 4691 4692 4693 4694 4695 4696 4697 4698
		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.
		 */
4699 4700 4701
		if (event->rb == rb)
			ring_buffer_attach(event, NULL);

4702
		mutex_unlock(&event->mmap_mutex);
4703
		put_event(event);
4704

4705 4706 4707 4708 4709
		/*
		 * Restart the iteration; either we're on the wrong list or
		 * destroyed its integrity by doing a deletion.
		 */
		goto again;
4710
	}
4711 4712 4713 4714 4715 4716 4717 4718 4719 4720 4721 4722 4723 4724 4725
	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);

4726
out_put:
4727
	ring_buffer_put(rb); /* could be last */
4728 4729
}

4730
static const struct vm_operations_struct perf_mmap_vmops = {
4731
	.open		= perf_mmap_open,
4732
	.close		= perf_mmap_close, /* non mergable */
4733 4734
	.fault		= perf_mmap_fault,
	.page_mkwrite	= perf_mmap_fault,
4735 4736 4737 4738
};

static int perf_mmap(struct file *file, struct vm_area_struct *vma)
{
4739
	struct perf_event *event = file->private_data;
4740
	unsigned long user_locked, user_lock_limit;
4741
	struct user_struct *user = current_user();
4742
	unsigned long locked, lock_limit;
4743
	struct ring_buffer *rb = NULL;
4744 4745
	unsigned long vma_size;
	unsigned long nr_pages;
4746
	long user_extra = 0, extra = 0;
4747
	int ret = 0, flags = 0;
4748

4749 4750 4751
	/*
	 * Don't allow mmap() of inherited per-task counters. This would
	 * create a performance issue due to all children writing to the
4752
	 * same rb.
4753 4754 4755 4756
	 */
	if (event->cpu == -1 && event->attr.inherit)
		return -EINVAL;

4757
	if (!(vma->vm_flags & VM_SHARED))
4758
		return -EINVAL;
4759 4760

	vma_size = vma->vm_end - vma->vm_start;
4761 4762 4763 4764 4765 4766 4767 4768 4769 4770 4771 4772 4773 4774 4775 4776 4777 4778 4779 4780 4781 4782 4783 4784 4785 4786 4787 4788 4789 4790 4791 4792 4793 4794 4795 4796 4797 4798 4799 4800 4801 4802 4803 4804 4805 4806 4807 4808 4809 4810 4811 4812 4813 4814 4815 4816 4817 4818 4819 4820

	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;
	}
4821

4822
	/*
4823
	 * If we have rb pages ensure they're a power-of-two number, so we
4824 4825
	 * can do bitmasks instead of modulo.
	 */
4826
	if (nr_pages != 0 && !is_power_of_2(nr_pages))
4827 4828
		return -EINVAL;

4829
	if (vma_size != PAGE_SIZE * (1 + nr_pages))
4830 4831
		return -EINVAL;

4832
	WARN_ON_ONCE(event->ctx->parent_ctx);
4833
again:
4834
	mutex_lock(&event->mmap_mutex);
4835
	if (event->rb) {
4836
		if (event->rb->nr_pages != nr_pages) {
4837
			ret = -EINVAL;
4838 4839 4840 4841 4842 4843 4844 4845 4846 4847 4848 4849 4850
			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;
		}

4851 4852 4853
		goto unlock;
	}

4854
	user_extra = nr_pages + 1;
4855 4856

accounting:
4857
	user_lock_limit = sysctl_perf_event_mlock >> (PAGE_SHIFT - 10);
I
Ingo Molnar 已提交
4858 4859 4860 4861 4862 4863

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

4864
	user_locked = atomic_long_read(&user->locked_vm) + user_extra;
4865

4866 4867
	if (user_locked > user_lock_limit)
		extra = user_locked - user_lock_limit;
4868

4869
	lock_limit = rlimit(RLIMIT_MEMLOCK);
4870
	lock_limit >>= PAGE_SHIFT;
4871
	locked = vma->vm_mm->pinned_vm + extra;
4872

4873 4874
	if ((locked > lock_limit) && perf_paranoid_tracepoint_raw() &&
		!capable(CAP_IPC_LOCK)) {
4875 4876 4877
		ret = -EPERM;
		goto unlock;
	}
4878

4879
	WARN_ON(!rb && event->rb);
4880

4881
	if (vma->vm_flags & VM_WRITE)
4882
		flags |= RING_BUFFER_WRITABLE;
4883

4884
	if (!rb) {
4885 4886 4887
		rb = rb_alloc(nr_pages,
			      event->attr.watermark ? event->attr.wakeup_watermark : 0,
			      event->cpu, flags);
P
Peter Zijlstra 已提交
4888

4889 4890 4891 4892
		if (!rb) {
			ret = -ENOMEM;
			goto unlock;
		}
4893

4894 4895 4896
		atomic_set(&rb->mmap_count, 1);
		rb->mmap_user = get_current_user();
		rb->mmap_locked = extra;
P
Peter Zijlstra 已提交
4897

4898
		ring_buffer_attach(event, rb);
4899

4900 4901 4902
		perf_event_init_userpage(event);
		perf_event_update_userpage(event);
	} else {
4903 4904
		ret = rb_alloc_aux(rb, event, vma->vm_pgoff, nr_pages,
				   event->attr.aux_watermark, flags);
4905 4906 4907
		if (!ret)
			rb->aux_mmap_locked = extra;
	}
4908

4909
unlock:
4910 4911 4912 4913
	if (!ret) {
		atomic_long_add(user_extra, &user->locked_vm);
		vma->vm_mm->pinned_vm += extra;

4914
		atomic_inc(&event->mmap_count);
4915 4916 4917 4918
	} else if (rb) {
		atomic_dec(&rb->mmap_count);
	}
aux_unlock:
4919
	mutex_unlock(&event->mmap_mutex);
4920

4921 4922 4923 4924
	/*
	 * Since pinned accounting is per vm we cannot allow fork() to copy our
	 * vma.
	 */
P
Peter Zijlstra 已提交
4925
	vma->vm_flags |= VM_DONTCOPY | VM_DONTEXPAND | VM_DONTDUMP;
4926
	vma->vm_ops = &perf_mmap_vmops;
4927

4928 4929 4930
	if (event->pmu->event_mapped)
		event->pmu->event_mapped(event);

4931
	return ret;
4932 4933
}

P
Peter Zijlstra 已提交
4934 4935
static int perf_fasync(int fd, struct file *filp, int on)
{
A
Al Viro 已提交
4936
	struct inode *inode = file_inode(filp);
4937
	struct perf_event *event = filp->private_data;
P
Peter Zijlstra 已提交
4938 4939
	int retval;

A
Al Viro 已提交
4940
	inode_lock(inode);
4941
	retval = fasync_helper(fd, filp, on, &event->fasync);
A
Al Viro 已提交
4942
	inode_unlock(inode);
P
Peter Zijlstra 已提交
4943 4944 4945 4946 4947 4948 4949

	if (retval < 0)
		return retval;

	return 0;
}

T
Thomas Gleixner 已提交
4950
static const struct file_operations perf_fops = {
4951
	.llseek			= no_llseek,
T
Thomas Gleixner 已提交
4952 4953 4954
	.release		= perf_release,
	.read			= perf_read,
	.poll			= perf_poll,
4955
	.unlocked_ioctl		= perf_ioctl,
P
Pawel Moll 已提交
4956
	.compat_ioctl		= perf_compat_ioctl,
4957
	.mmap			= perf_mmap,
P
Peter Zijlstra 已提交
4958
	.fasync			= perf_fasync,
T
Thomas Gleixner 已提交
4959 4960
};

4961
/*
4962
 * Perf event wakeup
4963 4964 4965 4966 4967
 *
 * If there's data, ensure we set the poll() state and publish everything
 * to user-space before waking everybody up.
 */

4968 4969 4970 4971 4972 4973 4974 4975
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;
}

4976
void perf_event_wakeup(struct perf_event *event)
4977
{
4978
	ring_buffer_wakeup(event);
4979

4980
	if (event->pending_kill) {
4981
		kill_fasync(perf_event_fasync(event), SIGIO, event->pending_kill);
4982
		event->pending_kill = 0;
4983
	}
4984 4985
}

4986
static void perf_pending_event(struct irq_work *entry)
4987
{
4988 4989
	struct perf_event *event = container_of(entry,
			struct perf_event, pending);
4990 4991 4992 4993 4994 4995 4996
	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'.
	 */
4997

4998 4999
	if (event->pending_disable) {
		event->pending_disable = 0;
5000
		perf_event_disable_local(event);
5001 5002
	}

5003 5004 5005
	if (event->pending_wakeup) {
		event->pending_wakeup = 0;
		perf_event_wakeup(event);
5006
	}
5007 5008 5009

	if (rctx >= 0)
		perf_swevent_put_recursion_context(rctx);
5010 5011
}

5012 5013 5014 5015 5016 5017 5018 5019 5020 5021 5022 5023 5024 5025 5026 5027 5028 5029 5030 5031 5032
/*
 * 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);

5033 5034 5035 5036 5037 5038 5039 5040 5041 5042 5043 5044 5045 5046 5047
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);
	}
}

5048
static void perf_sample_regs_user(struct perf_regs *regs_user,
5049 5050
				  struct pt_regs *regs,
				  struct pt_regs *regs_user_copy)
5051
{
5052 5053
	if (user_mode(regs)) {
		regs_user->abi = perf_reg_abi(current);
5054
		regs_user->regs = regs;
5055 5056
	} else if (current->mm) {
		perf_get_regs_user(regs_user, regs, regs_user_copy);
5057 5058 5059
	} else {
		regs_user->abi = PERF_SAMPLE_REGS_ABI_NONE;
		regs_user->regs = NULL;
5060 5061 5062
	}
}

5063 5064 5065 5066 5067 5068 5069 5070
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);
}


5071 5072 5073 5074 5075 5076 5077 5078 5079 5080 5081 5082 5083 5084 5085 5086 5087 5088 5089 5090 5091 5092 5093 5094 5095 5096 5097 5098 5099 5100 5101 5102 5103 5104 5105 5106 5107 5108 5109 5110 5111 5112 5113 5114 5115 5116 5117 5118 5119 5120 5121 5122 5123 5124 5125 5126 5127 5128 5129 5130 5131 5132 5133 5134 5135 5136 5137 5138 5139 5140 5141 5142 5143 5144 5145 5146 5147 5148 5149 5150 5151 5152 5153 5154 5155 5156 5157 5158 5159 5160 5161 5162 5163 5164 5165
/*
 * 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);
	}
}

5166 5167 5168
static void __perf_event_header__init_id(struct perf_event_header *header,
					 struct perf_sample_data *data,
					 struct perf_event *event)
5169 5170 5171 5172 5173 5174 5175 5176 5177 5178 5179 5180 5181
{
	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)
5182
		data->time = perf_event_clock(event);
5183

5184
	if (sample_type & (PERF_SAMPLE_ID | PERF_SAMPLE_IDENTIFIER))
5185 5186 5187 5188 5189 5190 5191 5192 5193 5194 5195
		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;
	}
}

5196 5197 5198
void perf_event_header__init_id(struct perf_event_header *header,
				struct perf_sample_data *data,
				struct perf_event *event)
5199 5200 5201 5202 5203 5204 5205 5206 5207 5208 5209 5210 5211 5212 5213 5214 5215 5216 5217 5218 5219 5220 5221 5222
{
	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);
5223 5224 5225

	if (sample_type & PERF_SAMPLE_IDENTIFIER)
		perf_output_put(handle, data->id);
5226 5227
}

5228 5229 5230
void perf_event__output_id_sample(struct perf_event *event,
				  struct perf_output_handle *handle,
				  struct perf_sample_data *sample)
5231 5232 5233 5234 5235
{
	if (event->attr.sample_id_all)
		__perf_event__output_id_sample(handle, sample);
}

5236
static void perf_output_read_one(struct perf_output_handle *handle,
5237 5238
				 struct perf_event *event,
				 u64 enabled, u64 running)
5239
{
5240
	u64 read_format = event->attr.read_format;
5241 5242 5243
	u64 values[4];
	int n = 0;

P
Peter Zijlstra 已提交
5244
	values[n++] = perf_event_count(event);
5245
	if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED) {
5246
		values[n++] = enabled +
5247
			atomic64_read(&event->child_total_time_enabled);
5248 5249
	}
	if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING) {
5250
		values[n++] = running +
5251
			atomic64_read(&event->child_total_time_running);
5252 5253
	}
	if (read_format & PERF_FORMAT_ID)
5254
		values[n++] = primary_event_id(event);
5255

5256
	__output_copy(handle, values, n * sizeof(u64));
5257 5258 5259
}

/*
5260
 * XXX PERF_FORMAT_GROUP vs inherited events seems difficult.
5261 5262
 */
static void perf_output_read_group(struct perf_output_handle *handle,
5263 5264
			    struct perf_event *event,
			    u64 enabled, u64 running)
5265
{
5266 5267
	struct perf_event *leader = event->group_leader, *sub;
	u64 read_format = event->attr.read_format;
5268 5269 5270 5271 5272 5273
	u64 values[5];
	int n = 0;

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

	if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED)
5274
		values[n++] = enabled;
5275 5276

	if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING)
5277
		values[n++] = running;
5278

5279
	if (leader != event)
5280 5281
		leader->pmu->read(leader);

P
Peter Zijlstra 已提交
5282
	values[n++] = perf_event_count(leader);
5283
	if (read_format & PERF_FORMAT_ID)
5284
		values[n++] = primary_event_id(leader);
5285

5286
	__output_copy(handle, values, n * sizeof(u64));
5287

5288
	list_for_each_entry(sub, &leader->sibling_list, group_entry) {
5289 5290
		n = 0;

5291 5292
		if ((sub != event) &&
		    (sub->state == PERF_EVENT_STATE_ACTIVE))
5293 5294
			sub->pmu->read(sub);

P
Peter Zijlstra 已提交
5295
		values[n++] = perf_event_count(sub);
5296
		if (read_format & PERF_FORMAT_ID)
5297
			values[n++] = primary_event_id(sub);
5298

5299
		__output_copy(handle, values, n * sizeof(u64));
5300 5301 5302
	}
}

5303 5304 5305
#define PERF_FORMAT_TOTAL_TIMES (PERF_FORMAT_TOTAL_TIME_ENABLED|\
				 PERF_FORMAT_TOTAL_TIME_RUNNING)

5306
static void perf_output_read(struct perf_output_handle *handle,
5307
			     struct perf_event *event)
5308
{
5309
	u64 enabled = 0, running = 0, now;
5310 5311 5312 5313 5314 5315 5316 5317 5318 5319 5320
	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
	 */
5321
	if (read_format & PERF_FORMAT_TOTAL_TIMES)
5322
		calc_timer_values(event, &now, &enabled, &running);
5323

5324
	if (event->attr.read_format & PERF_FORMAT_GROUP)
5325
		perf_output_read_group(handle, event, enabled, running);
5326
	else
5327
		perf_output_read_one(handle, event, enabled, running);
5328 5329
}

5330 5331 5332
void perf_output_sample(struct perf_output_handle *handle,
			struct perf_event_header *header,
			struct perf_sample_data *data,
5333
			struct perf_event *event)
5334 5335 5336 5337 5338
{
	u64 sample_type = data->type;

	perf_output_put(handle, *header);

5339 5340 5341
	if (sample_type & PERF_SAMPLE_IDENTIFIER)
		perf_output_put(handle, data->id);

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
	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)
5367
		perf_output_read(handle, event);
5368 5369 5370 5371 5372 5373 5374 5375 5376 5377

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

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

			size *= sizeof(u64);

5378
			__output_copy(handle, data->callchain, size);
5379 5380 5381 5382 5383 5384 5385 5386
		} else {
			u64 nr = 0;
			perf_output_put(handle, nr);
		}
	}

	if (sample_type & PERF_SAMPLE_RAW) {
		if (data->raw) {
5387 5388 5389 5390 5391 5392 5393 5394 5395
			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);
5396 5397 5398 5399 5400 5401 5402 5403 5404 5405 5406
		} else {
			struct {
				u32	size;
				u32	data;
			} raw = {
				.size = sizeof(u32),
				.data = 0,
			};
			perf_output_put(handle, raw);
		}
	}
5407

5408 5409 5410 5411 5412 5413 5414 5415 5416 5417 5418 5419 5420 5421 5422 5423 5424
	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);
		}
	}
5425 5426 5427 5428 5429 5430 5431 5432 5433 5434 5435 5436 5437 5438 5439 5440 5441

	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);
		}
	}
5442

5443
	if (sample_type & PERF_SAMPLE_STACK_USER) {
5444 5445 5446
		perf_output_sample_ustack(handle,
					  data->stack_user_size,
					  data->regs_user.regs);
5447
	}
A
Andi Kleen 已提交
5448 5449 5450

	if (sample_type & PERF_SAMPLE_WEIGHT)
		perf_output_put(handle, data->weight);
5451 5452 5453

	if (sample_type & PERF_SAMPLE_DATA_SRC)
		perf_output_put(handle, data->data_src.val);
5454

A
Andi Kleen 已提交
5455 5456 5457
	if (sample_type & PERF_SAMPLE_TRANSACTION)
		perf_output_put(handle, data->txn);

5458 5459 5460 5461 5462 5463 5464 5465 5466 5467 5468 5469 5470 5471 5472 5473 5474
	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);
		}
	}

5475 5476 5477 5478 5479 5480 5481 5482 5483 5484 5485 5486 5487
	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);
			}
		}
	}
5488 5489 5490 5491
}

void perf_prepare_sample(struct perf_event_header *header,
			 struct perf_sample_data *data,
5492
			 struct perf_event *event,
5493
			 struct pt_regs *regs)
5494
{
5495
	u64 sample_type = event->attr.sample_type;
5496

5497
	header->type = PERF_RECORD_SAMPLE;
5498
	header->size = sizeof(*header) + event->header_size;
5499 5500 5501

	header->misc = 0;
	header->misc |= perf_misc_flags(regs);
5502

5503
	__perf_event_header__init_id(header, data, event);
5504

5505
	if (sample_type & PERF_SAMPLE_IP)
5506 5507
		data->ip = perf_instruction_pointer(regs);

5508
	if (sample_type & PERF_SAMPLE_CALLCHAIN) {
5509
		int size = 1;
5510

5511
		data->callchain = perf_callchain(event, regs);
5512 5513 5514 5515 5516

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

		header->size += size * sizeof(u64);
5517 5518
	}

5519
	if (sample_type & PERF_SAMPLE_RAW) {
5520 5521 5522 5523 5524 5525 5526
		int size = sizeof(u32);

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

5527
		header->size += round_up(size, sizeof(u64));
5528
	}
5529 5530 5531 5532 5533 5534 5535 5536 5537

	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;
	}
5538

5539
	if (sample_type & (PERF_SAMPLE_REGS_USER | PERF_SAMPLE_STACK_USER))
5540 5541
		perf_sample_regs_user(&data->regs_user, regs,
				      &data->regs_user_copy);
5542

5543 5544 5545 5546 5547 5548 5549 5550 5551 5552 5553
	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;
	}
5554 5555 5556 5557 5558 5559 5560 5561 5562 5563 5564 5565

	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,
5566
						     data->regs_user.regs);
5567 5568 5569 5570 5571 5572 5573 5574 5575 5576 5577 5578

		/*
		 * 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;
	}
5579 5580 5581 5582 5583 5584 5585 5586 5587 5588 5589 5590 5591 5592 5593

	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;
	}
5594
}
5595

5596 5597 5598
void perf_event_output(struct perf_event *event,
			struct perf_sample_data *data,
			struct pt_regs *regs)
5599 5600 5601
{
	struct perf_output_handle handle;
	struct perf_event_header header;
5602

5603 5604 5605
	/* protect the callchain buffers */
	rcu_read_lock();

5606
	perf_prepare_sample(&header, data, event, regs);
P
Peter Zijlstra 已提交
5607

5608
	if (perf_output_begin(&handle, event, header.size))
5609
		goto exit;
5610

5611
	perf_output_sample(&handle, &header, data, event);
5612

5613
	perf_output_end(&handle);
5614 5615 5616

exit:
	rcu_read_unlock();
5617 5618
}

5619
/*
5620
 * read event_id
5621 5622 5623 5624 5625 5626 5627 5628 5629 5630
 */

struct perf_read_event {
	struct perf_event_header	header;

	u32				pid;
	u32				tid;
};

static void
5631
perf_event_read_event(struct perf_event *event,
5632 5633 5634
			struct task_struct *task)
{
	struct perf_output_handle handle;
5635
	struct perf_sample_data sample;
5636
	struct perf_read_event read_event = {
5637
		.header = {
5638
			.type = PERF_RECORD_READ,
5639
			.misc = 0,
5640
			.size = sizeof(read_event) + event->read_size,
5641
		},
5642 5643
		.pid = perf_event_pid(event, task),
		.tid = perf_event_tid(event, task),
5644
	};
5645
	int ret;
5646

5647
	perf_event_header__init_id(&read_event.header, &sample, event);
5648
	ret = perf_output_begin(&handle, event, read_event.header.size);
5649 5650 5651
	if (ret)
		return;

5652
	perf_output_put(&handle, read_event);
5653
	perf_output_read(&handle, event);
5654
	perf_event__output_id_sample(event, &handle, &sample);
5655

5656 5657 5658
	perf_output_end(&handle);
}

5659 5660 5661 5662 5663 5664 5665 5666 5667 5668 5669 5670 5671 5672
typedef void (perf_event_aux_output_cb)(struct perf_event *event, void *data);

static void
perf_event_aux_ctx(struct perf_event_context *ctx,
		   perf_event_aux_output_cb output,
		   void *data)
{
	struct perf_event *event;

	list_for_each_entry_rcu(event, &ctx->event_list, event_entry) {
		if (event->state < PERF_EVENT_STATE_INACTIVE)
			continue;
		if (!event_filter_match(event))
			continue;
5673
		output(event, data);
5674 5675 5676
	}
}

J
Jiri Olsa 已提交
5677 5678 5679 5680 5681 5682 5683 5684 5685 5686 5687
static void
perf_event_aux_task_ctx(perf_event_aux_output_cb output, void *data,
			struct perf_event_context *task_ctx)
{
	rcu_read_lock();
	preempt_disable();
	perf_event_aux_ctx(task_ctx, output, data);
	preempt_enable();
	rcu_read_unlock();
}

5688
static void
5689
perf_event_aux(perf_event_aux_output_cb output, void *data,
5690 5691 5692 5693 5694 5695 5696
	       struct perf_event_context *task_ctx)
{
	struct perf_cpu_context *cpuctx;
	struct perf_event_context *ctx;
	struct pmu *pmu;
	int ctxn;

J
Jiri Olsa 已提交
5697 5698 5699 5700 5701 5702 5703 5704 5705 5706 5707
	/*
	 * 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
	 * context.
	 */
	if (task_ctx) {
		perf_event_aux_task_ctx(output, data, task_ctx);
		return;
	}

5708 5709 5710 5711 5712
	rcu_read_lock();
	list_for_each_entry_rcu(pmu, &pmus, entry) {
		cpuctx = get_cpu_ptr(pmu->pmu_cpu_context);
		if (cpuctx->unique_pmu != pmu)
			goto next;
5713
		perf_event_aux_ctx(&cpuctx->ctx, output, data);
5714 5715 5716 5717 5718
		ctxn = pmu->task_ctx_nr;
		if (ctxn < 0)
			goto next;
		ctx = rcu_dereference(current->perf_event_ctxp[ctxn]);
		if (ctx)
5719
			perf_event_aux_ctx(ctx, output, data);
5720 5721 5722 5723 5724 5725
next:
		put_cpu_ptr(pmu->pmu_cpu_context);
	}
	rcu_read_unlock();
}

P
Peter Zijlstra 已提交
5726
/*
P
Peter Zijlstra 已提交
5727 5728
 * task tracking -- fork/exit
 *
5729
 * enabled by: attr.comm | attr.mmap | attr.mmap2 | attr.mmap_data | attr.task
P
Peter Zijlstra 已提交
5730 5731
 */

P
Peter Zijlstra 已提交
5732
struct perf_task_event {
5733
	struct task_struct		*task;
5734
	struct perf_event_context	*task_ctx;
P
Peter Zijlstra 已提交
5735 5736 5737 5738 5739 5740

	struct {
		struct perf_event_header	header;

		u32				pid;
		u32				ppid;
P
Peter Zijlstra 已提交
5741 5742
		u32				tid;
		u32				ptid;
5743
		u64				time;
5744
	} event_id;
P
Peter Zijlstra 已提交
5745 5746
};

5747 5748
static int perf_event_task_match(struct perf_event *event)
{
5749 5750 5751
	return event->attr.comm  || event->attr.mmap ||
	       event->attr.mmap2 || event->attr.mmap_data ||
	       event->attr.task;
5752 5753
}

5754
static void perf_event_task_output(struct perf_event *event,
5755
				   void *data)
P
Peter Zijlstra 已提交
5756
{
5757
	struct perf_task_event *task_event = data;
P
Peter Zijlstra 已提交
5758
	struct perf_output_handle handle;
5759
	struct perf_sample_data	sample;
P
Peter Zijlstra 已提交
5760
	struct task_struct *task = task_event->task;
5761
	int ret, size = task_event->event_id.header.size;
5762

5763 5764 5765
	if (!perf_event_task_match(event))
		return;

5766
	perf_event_header__init_id(&task_event->event_id.header, &sample, event);
P
Peter Zijlstra 已提交
5767

5768
	ret = perf_output_begin(&handle, event,
5769
				task_event->event_id.header.size);
5770
	if (ret)
5771
		goto out;
P
Peter Zijlstra 已提交
5772

5773 5774
	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
5775

5776 5777
	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
5778

5779 5780
	task_event->event_id.time = perf_event_clock(event);

5781
	perf_output_put(&handle, task_event->event_id);
5782

5783 5784
	perf_event__output_id_sample(event, &handle, &sample);

P
Peter Zijlstra 已提交
5785
	perf_output_end(&handle);
5786 5787
out:
	task_event->event_id.header.size = size;
P
Peter Zijlstra 已提交
5788 5789
}

5790 5791
static void perf_event_task(struct task_struct *task,
			      struct perf_event_context *task_ctx,
5792
			      int new)
P
Peter Zijlstra 已提交
5793
{
P
Peter Zijlstra 已提交
5794
	struct perf_task_event task_event;
P
Peter Zijlstra 已提交
5795

5796 5797 5798
	if (!atomic_read(&nr_comm_events) &&
	    !atomic_read(&nr_mmap_events) &&
	    !atomic_read(&nr_task_events))
P
Peter Zijlstra 已提交
5799 5800
		return;

P
Peter Zijlstra 已提交
5801
	task_event = (struct perf_task_event){
5802 5803
		.task	  = task,
		.task_ctx = task_ctx,
5804
		.event_id    = {
P
Peter Zijlstra 已提交
5805
			.header = {
5806
				.type = new ? PERF_RECORD_FORK : PERF_RECORD_EXIT,
5807
				.misc = 0,
5808
				.size = sizeof(task_event.event_id),
P
Peter Zijlstra 已提交
5809
			},
5810 5811
			/* .pid  */
			/* .ppid */
P
Peter Zijlstra 已提交
5812 5813
			/* .tid  */
			/* .ptid */
5814
			/* .time */
P
Peter Zijlstra 已提交
5815 5816 5817
		},
	};

5818
	perf_event_aux(perf_event_task_output,
5819 5820
		       &task_event,
		       task_ctx);
P
Peter Zijlstra 已提交
5821 5822
}

5823
void perf_event_fork(struct task_struct *task)
P
Peter Zijlstra 已提交
5824
{
5825
	perf_event_task(task, NULL, 1);
P
Peter Zijlstra 已提交
5826 5827
}

5828 5829 5830 5831 5832
/*
 * comm tracking
 */

struct perf_comm_event {
5833 5834
	struct task_struct	*task;
	char			*comm;
5835 5836 5837 5838 5839 5840 5841
	int			comm_size;

	struct {
		struct perf_event_header	header;

		u32				pid;
		u32				tid;
5842
	} event_id;
5843 5844
};

5845 5846 5847 5848 5849
static int perf_event_comm_match(struct perf_event *event)
{
	return event->attr.comm;
}

5850
static void perf_event_comm_output(struct perf_event *event,
5851
				   void *data)
5852
{
5853
	struct perf_comm_event *comm_event = data;
5854
	struct perf_output_handle handle;
5855
	struct perf_sample_data sample;
5856
	int size = comm_event->event_id.header.size;
5857 5858
	int ret;

5859 5860 5861
	if (!perf_event_comm_match(event))
		return;

5862 5863
	perf_event_header__init_id(&comm_event->event_id.header, &sample, event);
	ret = perf_output_begin(&handle, event,
5864
				comm_event->event_id.header.size);
5865 5866

	if (ret)
5867
		goto out;
5868

5869 5870
	comm_event->event_id.pid = perf_event_pid(event, comm_event->task);
	comm_event->event_id.tid = perf_event_tid(event, comm_event->task);
5871

5872
	perf_output_put(&handle, comm_event->event_id);
5873
	__output_copy(&handle, comm_event->comm,
5874
				   comm_event->comm_size);
5875 5876 5877

	perf_event__output_id_sample(event, &handle, &sample);

5878
	perf_output_end(&handle);
5879 5880
out:
	comm_event->event_id.header.size = size;
5881 5882
}

5883
static void perf_event_comm_event(struct perf_comm_event *comm_event)
5884
{
5885
	char comm[TASK_COMM_LEN];
5886 5887
	unsigned int size;

5888
	memset(comm, 0, sizeof(comm));
5889
	strlcpy(comm, comm_event->task->comm, sizeof(comm));
5890
	size = ALIGN(strlen(comm)+1, sizeof(u64));
5891 5892 5893 5894

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

5895
	comm_event->event_id.header.size = sizeof(comm_event->event_id) + size;
P
Peter Zijlstra 已提交
5896

5897
	perf_event_aux(perf_event_comm_output,
5898 5899
		       comm_event,
		       NULL);
5900 5901
}

5902
void perf_event_comm(struct task_struct *task, bool exec)
5903
{
5904 5905
	struct perf_comm_event comm_event;

5906
	if (!atomic_read(&nr_comm_events))
5907
		return;
5908

5909
	comm_event = (struct perf_comm_event){
5910
		.task	= task,
5911 5912
		/* .comm      */
		/* .comm_size */
5913
		.event_id  = {
5914
			.header = {
5915
				.type = PERF_RECORD_COMM,
5916
				.misc = exec ? PERF_RECORD_MISC_COMM_EXEC : 0,
5917 5918 5919 5920
				/* .size */
			},
			/* .pid */
			/* .tid */
5921 5922 5923
		},
	};

5924
	perf_event_comm_event(&comm_event);
5925 5926
}

5927 5928 5929 5930 5931
/*
 * mmap tracking
 */

struct perf_mmap_event {
5932 5933 5934 5935
	struct vm_area_struct	*vma;

	const char		*file_name;
	int			file_size;
5936 5937 5938
	int			maj, min;
	u64			ino;
	u64			ino_generation;
5939
	u32			prot, flags;
5940 5941 5942 5943 5944 5945 5946 5947 5948

	struct {
		struct perf_event_header	header;

		u32				pid;
		u32				tid;
		u64				start;
		u64				len;
		u64				pgoff;
5949
	} event_id;
5950 5951
};

5952 5953 5954 5955 5956 5957 5958 5959
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) ||
5960
	       (executable && (event->attr.mmap || event->attr.mmap2));
5961 5962
}

5963
static void perf_event_mmap_output(struct perf_event *event,
5964
				   void *data)
5965
{
5966
	struct perf_mmap_event *mmap_event = data;
5967
	struct perf_output_handle handle;
5968
	struct perf_sample_data sample;
5969
	int size = mmap_event->event_id.header.size;
5970
	int ret;
5971

5972 5973 5974
	if (!perf_event_mmap_match(event, data))
		return;

5975 5976 5977 5978 5979
	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);
5980
		mmap_event->event_id.header.size += sizeof(mmap_event->ino_generation);
5981 5982
		mmap_event->event_id.header.size += sizeof(mmap_event->prot);
		mmap_event->event_id.header.size += sizeof(mmap_event->flags);
5983 5984
	}

5985 5986
	perf_event_header__init_id(&mmap_event->event_id.header, &sample, event);
	ret = perf_output_begin(&handle, event,
5987
				mmap_event->event_id.header.size);
5988
	if (ret)
5989
		goto out;
5990

5991 5992
	mmap_event->event_id.pid = perf_event_pid(event, current);
	mmap_event->event_id.tid = perf_event_tid(event, current);
5993

5994
	perf_output_put(&handle, mmap_event->event_id);
5995 5996 5997 5998 5999 6000

	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);
6001 6002
		perf_output_put(&handle, mmap_event->prot);
		perf_output_put(&handle, mmap_event->flags);
6003 6004
	}

6005
	__output_copy(&handle, mmap_event->file_name,
6006
				   mmap_event->file_size);
6007 6008 6009

	perf_event__output_id_sample(event, &handle, &sample);

6010
	perf_output_end(&handle);
6011 6012
out:
	mmap_event->event_id.header.size = size;
6013 6014
}

6015
static void perf_event_mmap_event(struct perf_mmap_event *mmap_event)
6016
{
6017 6018
	struct vm_area_struct *vma = mmap_event->vma;
	struct file *file = vma->vm_file;
6019 6020
	int maj = 0, min = 0;
	u64 ino = 0, gen = 0;
6021
	u32 prot = 0, flags = 0;
6022 6023 6024
	unsigned int size;
	char tmp[16];
	char *buf = NULL;
6025
	char *name;
6026

6027
	if (file) {
6028 6029
		struct inode *inode;
		dev_t dev;
6030

6031
		buf = kmalloc(PATH_MAX, GFP_KERNEL);
6032
		if (!buf) {
6033 6034
			name = "//enomem";
			goto cpy_name;
6035
		}
6036
		/*
6037
		 * d_path() works from the end of the rb backwards, so we
6038 6039 6040
		 * need to add enough zero bytes after the string to handle
		 * the 64bit alignment we do later.
		 */
M
Miklos Szeredi 已提交
6041
		name = file_path(file, buf, PATH_MAX - sizeof(u64));
6042
		if (IS_ERR(name)) {
6043 6044
			name = "//toolong";
			goto cpy_name;
6045
		}
6046 6047 6048 6049 6050 6051
		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);
6052 6053 6054 6055 6056 6057 6058 6059 6060 6061 6062 6063 6064 6065 6066 6067 6068 6069 6070 6071 6072 6073

		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;

6074
		goto got_name;
6075
	} else {
6076 6077 6078 6079 6080 6081
		if (vma->vm_ops && vma->vm_ops->name) {
			name = (char *) vma->vm_ops->name(vma);
			if (name)
				goto cpy_name;
		}

6082
		name = (char *)arch_vma_name(vma);
6083 6084
		if (name)
			goto cpy_name;
6085

6086
		if (vma->vm_start <= vma->vm_mm->start_brk &&
6087
				vma->vm_end >= vma->vm_mm->brk) {
6088 6089
			name = "[heap]";
			goto cpy_name;
6090 6091
		}
		if (vma->vm_start <= vma->vm_mm->start_stack &&
6092
				vma->vm_end >= vma->vm_mm->start_stack) {
6093 6094
			name = "[stack]";
			goto cpy_name;
6095 6096
		}

6097 6098
		name = "//anon";
		goto cpy_name;
6099 6100
	}

6101 6102 6103
cpy_name:
	strlcpy(tmp, name, sizeof(tmp));
	name = tmp;
6104
got_name:
6105 6106 6107 6108 6109 6110 6111 6112
	/*
	 * 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';
6113 6114 6115

	mmap_event->file_name = name;
	mmap_event->file_size = size;
6116 6117 6118 6119
	mmap_event->maj = maj;
	mmap_event->min = min;
	mmap_event->ino = ino;
	mmap_event->ino_generation = gen;
6120 6121
	mmap_event->prot = prot;
	mmap_event->flags = flags;
6122

6123 6124 6125
	if (!(vma->vm_flags & VM_EXEC))
		mmap_event->event_id.header.misc |= PERF_RECORD_MISC_MMAP_DATA;

6126
	mmap_event->event_id.header.size = sizeof(mmap_event->event_id) + size;
6127

6128
	perf_event_aux(perf_event_mmap_output,
6129 6130
		       mmap_event,
		       NULL);
6131

6132 6133 6134
	kfree(buf);
}

6135
void perf_event_mmap(struct vm_area_struct *vma)
6136
{
6137 6138
	struct perf_mmap_event mmap_event;

6139
	if (!atomic_read(&nr_mmap_events))
6140 6141 6142
		return;

	mmap_event = (struct perf_mmap_event){
6143
		.vma	= vma,
6144 6145
		/* .file_name */
		/* .file_size */
6146
		.event_id  = {
6147
			.header = {
6148
				.type = PERF_RECORD_MMAP,
6149
				.misc = PERF_RECORD_MISC_USER,
6150 6151 6152 6153
				/* .size */
			},
			/* .pid */
			/* .tid */
6154 6155
			.start  = vma->vm_start,
			.len    = vma->vm_end - vma->vm_start,
6156
			.pgoff  = (u64)vma->vm_pgoff << PAGE_SHIFT,
6157
		},
6158 6159 6160 6161
		/* .maj (attr_mmap2 only) */
		/* .min (attr_mmap2 only) */
		/* .ino (attr_mmap2 only) */
		/* .ino_generation (attr_mmap2 only) */
6162 6163
		/* .prot (attr_mmap2 only) */
		/* .flags (attr_mmap2 only) */
6164 6165
	};

6166
	perf_event_mmap_event(&mmap_event);
6167 6168
}

A
Alexander Shishkin 已提交
6169 6170 6171 6172 6173 6174 6175 6176 6177 6178 6179 6180 6181 6182 6183 6184 6185 6186 6187 6188 6189 6190 6191 6192 6193 6194 6195 6196 6197 6198 6199 6200 6201 6202
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);
}

6203 6204 6205 6206 6207 6208 6209 6210 6211 6212 6213 6214 6215 6216 6217 6218 6219 6220 6221 6222 6223 6224 6225 6226 6227 6228 6229 6230 6231 6232 6233 6234 6235
/*
 * 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);
}

6236 6237 6238 6239 6240 6241 6242 6243 6244 6245 6246 6247 6248 6249 6250 6251 6252 6253 6254 6255 6256 6257 6258 6259 6260 6261 6262 6263 6264 6265 6266 6267 6268 6269 6270 6271 6272 6273 6274 6275 6276 6277 6278 6279 6280 6281 6282 6283 6284 6285 6286 6287 6288 6289 6290 6291 6292 6293 6294 6295 6296 6297 6298 6299 6300 6301 6302 6303 6304 6305 6306 6307 6308 6309 6310 6311 6312 6313 6314 6315 6316 6317 6318 6319 6320
/*
 * 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 */
		},
	};

	perf_event_aux(perf_event_switch_output,
		       &switch_event,
		       NULL);
}

6321 6322 6323 6324
/*
 * IRQ throttle logging
 */

6325
static void perf_log_throttle(struct perf_event *event, int enable)
6326 6327
{
	struct perf_output_handle handle;
6328
	struct perf_sample_data sample;
6329 6330 6331 6332 6333
	int ret;

	struct {
		struct perf_event_header	header;
		u64				time;
6334
		u64				id;
6335
		u64				stream_id;
6336 6337
	} throttle_event = {
		.header = {
6338
			.type = PERF_RECORD_THROTTLE,
6339 6340 6341
			.misc = 0,
			.size = sizeof(throttle_event),
		},
6342
		.time		= perf_event_clock(event),
6343 6344
		.id		= primary_event_id(event),
		.stream_id	= event->id,
6345 6346
	};

6347
	if (enable)
6348
		throttle_event.header.type = PERF_RECORD_UNTHROTTLE;
6349

6350 6351 6352
	perf_event_header__init_id(&throttle_event.header, &sample, event);

	ret = perf_output_begin(&handle, event,
6353
				throttle_event.header.size);
6354 6355 6356 6357
	if (ret)
		return;

	perf_output_put(&handle, throttle_event);
6358
	perf_event__output_id_sample(event, &handle, &sample);
6359 6360 6361
	perf_output_end(&handle);
}

6362 6363 6364 6365 6366 6367 6368 6369 6370 6371 6372 6373 6374 6375 6376 6377 6378 6379 6380 6381 6382 6383 6384 6385 6386 6387 6388 6389 6390 6391 6392 6393 6394 6395 6396 6397
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);
}

6398
/*
6399
 * Generic event overflow handling, sampling.
6400 6401
 */

6402
static int __perf_event_overflow(struct perf_event *event,
6403 6404
				   int throttle, struct perf_sample_data *data,
				   struct pt_regs *regs)
6405
{
6406 6407
	int events = atomic_read(&event->event_limit);
	struct hw_perf_event *hwc = &event->hw;
6408
	u64 seq;
6409 6410
	int ret = 0;

6411 6412 6413 6414 6415 6416 6417
	/*
	 * Non-sampling counters might still use the PMI to fold short
	 * hardware counters, ignore those.
	 */
	if (unlikely(!is_sampling_event(event)))
		return 0;

6418 6419 6420 6421 6422 6423 6424 6425 6426
	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);
P
Peter Zijlstra 已提交
6427 6428
			hwc->interrupts = MAX_INTERRUPTS;
			perf_log_throttle(event, 0);
6429
			tick_nohz_full_kick();
6430 6431
			ret = 1;
		}
6432
	}
6433

6434
	if (event->attr.freq) {
P
Peter Zijlstra 已提交
6435
		u64 now = perf_clock();
6436
		s64 delta = now - hwc->freq_time_stamp;
6437

6438
		hwc->freq_time_stamp = now;
6439

6440
		if (delta > 0 && delta < 2*TICK_NSEC)
6441
			perf_adjust_period(event, delta, hwc->last_period, true);
6442 6443
	}

6444 6445
	/*
	 * XXX event_limit might not quite work as expected on inherited
6446
	 * events
6447 6448
	 */

6449 6450
	event->pending_kill = POLL_IN;
	if (events && atomic_dec_and_test(&event->event_limit)) {
6451
		ret = 1;
6452
		event->pending_kill = POLL_HUP;
6453 6454
		event->pending_disable = 1;
		irq_work_queue(&event->pending);
6455 6456
	}

6457
	if (event->overflow_handler)
6458
		event->overflow_handler(event, data, regs);
6459
	else
6460
		perf_event_output(event, data, regs);
6461

6462
	if (*perf_event_fasync(event) && event->pending_kill) {
6463 6464
		event->pending_wakeup = 1;
		irq_work_queue(&event->pending);
P
Peter Zijlstra 已提交
6465 6466
	}

6467
	return ret;
6468 6469
}

6470
int perf_event_overflow(struct perf_event *event,
6471 6472
			  struct perf_sample_data *data,
			  struct pt_regs *regs)
6473
{
6474
	return __perf_event_overflow(event, 1, data, regs);
6475 6476
}

6477
/*
6478
 * Generic software event infrastructure
6479 6480
 */

6481 6482 6483 6484 6485 6486 6487 6488 6489 6490 6491
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);

6492
/*
6493 6494
 * We directly increment event->count and keep a second value in
 * event->hw.period_left to count intervals. This period event
6495 6496 6497 6498
 * is kept in the range [-sample_period, 0] so that we can use the
 * sign as trigger.
 */

6499
u64 perf_swevent_set_period(struct perf_event *event)
6500
{
6501
	struct hw_perf_event *hwc = &event->hw;
6502 6503 6504 6505 6506
	u64 period = hwc->last_period;
	u64 nr, offset;
	s64 old, val;

	hwc->last_period = hwc->sample_period;
6507 6508

again:
6509
	old = val = local64_read(&hwc->period_left);
6510 6511
	if (val < 0)
		return 0;
6512

6513 6514 6515
	nr = div64_u64(period + val, period);
	offset = nr * period;
	val -= offset;
6516
	if (local64_cmpxchg(&hwc->period_left, old, val) != old)
6517
		goto again;
6518

6519
	return nr;
6520 6521
}

6522
static void perf_swevent_overflow(struct perf_event *event, u64 overflow,
6523
				    struct perf_sample_data *data,
6524
				    struct pt_regs *regs)
6525
{
6526
	struct hw_perf_event *hwc = &event->hw;
6527
	int throttle = 0;
6528

6529 6530
	if (!overflow)
		overflow = perf_swevent_set_period(event);
6531

6532 6533
	if (hwc->interrupts == MAX_INTERRUPTS)
		return;
6534

6535
	for (; overflow; overflow--) {
6536
		if (__perf_event_overflow(event, throttle,
6537
					    data, regs)) {
6538 6539 6540 6541 6542 6543
			/*
			 * We inhibit the overflow from happening when
			 * hwc->interrupts == MAX_INTERRUPTS.
			 */
			break;
		}
6544
		throttle = 1;
6545
	}
6546 6547
}

P
Peter Zijlstra 已提交
6548
static void perf_swevent_event(struct perf_event *event, u64 nr,
6549
			       struct perf_sample_data *data,
6550
			       struct pt_regs *regs)
6551
{
6552
	struct hw_perf_event *hwc = &event->hw;
6553

6554
	local64_add(nr, &event->count);
6555

6556 6557 6558
	if (!regs)
		return;

6559
	if (!is_sampling_event(event))
6560
		return;
6561

6562 6563 6564 6565 6566 6567
	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;

6568
	if (nr == 1 && hwc->sample_period == 1 && !event->attr.freq)
6569
		return perf_swevent_overflow(event, 1, data, regs);
6570

6571
	if (local64_add_negative(nr, &hwc->period_left))
6572
		return;
6573

6574
	perf_swevent_overflow(event, 0, data, regs);
6575 6576
}

6577 6578 6579
static int perf_exclude_event(struct perf_event *event,
			      struct pt_regs *regs)
{
P
Peter Zijlstra 已提交
6580
	if (event->hw.state & PERF_HES_STOPPED)
6581
		return 1;
P
Peter Zijlstra 已提交
6582

6583 6584 6585 6586 6587 6588 6589 6590 6591 6592 6593
	if (regs) {
		if (event->attr.exclude_user && user_mode(regs))
			return 1;

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

	return 0;
}

6594
static int perf_swevent_match(struct perf_event *event,
P
Peter Zijlstra 已提交
6595
				enum perf_type_id type,
L
Li Zefan 已提交
6596 6597 6598
				u32 event_id,
				struct perf_sample_data *data,
				struct pt_regs *regs)
6599
{
6600
	if (event->attr.type != type)
6601
		return 0;
6602

6603
	if (event->attr.config != event_id)
6604 6605
		return 0;

6606 6607
	if (perf_exclude_event(event, regs))
		return 0;
6608 6609 6610 6611

	return 1;
}

6612 6613 6614 6615 6616 6617 6618
static inline u64 swevent_hash(u64 type, u32 event_id)
{
	u64 val = event_id | (type << 32);

	return hash_64(val, SWEVENT_HLIST_BITS);
}

6619 6620
static inline struct hlist_head *
__find_swevent_head(struct swevent_hlist *hlist, u64 type, u32 event_id)
6621
{
6622 6623 6624 6625
	u64 hash = swevent_hash(type, event_id);

	return &hlist->heads[hash];
}
6626

6627 6628
/* For the read side: events when they trigger */
static inline struct hlist_head *
6629
find_swevent_head_rcu(struct swevent_htable *swhash, u64 type, u32 event_id)
6630 6631
{
	struct swevent_hlist *hlist;
6632

6633
	hlist = rcu_dereference(swhash->swevent_hlist);
6634 6635 6636
	if (!hlist)
		return NULL;

6637 6638 6639 6640 6641
	return __find_swevent_head(hlist, type, event_id);
}

/* For the event head insertion and removal in the hlist */
static inline struct hlist_head *
6642
find_swevent_head(struct swevent_htable *swhash, struct perf_event *event)
6643 6644 6645 6646 6647 6648 6649 6650 6651 6652
{
	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.
	 */
6653
	hlist = rcu_dereference_protected(swhash->swevent_hlist,
6654 6655 6656 6657 6658
					  lockdep_is_held(&event->ctx->lock));
	if (!hlist)
		return NULL;

	return __find_swevent_head(hlist, type, event_id);
6659 6660 6661
}

static void do_perf_sw_event(enum perf_type_id type, u32 event_id,
6662
				    u64 nr,
6663 6664
				    struct perf_sample_data *data,
				    struct pt_regs *regs)
6665
{
6666
	struct swevent_htable *swhash = this_cpu_ptr(&swevent_htable);
6667
	struct perf_event *event;
6668
	struct hlist_head *head;
6669

6670
	rcu_read_lock();
6671
	head = find_swevent_head_rcu(swhash, type, event_id);
6672 6673 6674
	if (!head)
		goto end;

6675
	hlist_for_each_entry_rcu(event, head, hlist_entry) {
L
Li Zefan 已提交
6676
		if (perf_swevent_match(event, type, event_id, data, regs))
6677
			perf_swevent_event(event, nr, data, regs);
6678
	}
6679 6680
end:
	rcu_read_unlock();
6681 6682
}

6683 6684
DEFINE_PER_CPU(struct pt_regs, __perf_regs[4]);

6685
int perf_swevent_get_recursion_context(void)
P
Peter Zijlstra 已提交
6686
{
6687
	struct swevent_htable *swhash = this_cpu_ptr(&swevent_htable);
P
Peter Zijlstra 已提交
6688

6689
	return get_recursion_context(swhash->recursion);
P
Peter Zijlstra 已提交
6690
}
I
Ingo Molnar 已提交
6691
EXPORT_SYMBOL_GPL(perf_swevent_get_recursion_context);
P
Peter Zijlstra 已提交
6692

6693
inline void perf_swevent_put_recursion_context(int rctx)
6694
{
6695
	struct swevent_htable *swhash = this_cpu_ptr(&swevent_htable);
6696

6697
	put_recursion_context(swhash->recursion, rctx);
6698
}
6699

6700
void ___perf_sw_event(u32 event_id, u64 nr, struct pt_regs *regs, u64 addr)
6701
{
6702
	struct perf_sample_data data;
6703

6704
	if (WARN_ON_ONCE(!regs))
6705
		return;
6706

6707
	perf_sample_data_init(&data, addr, 0);
6708
	do_perf_sw_event(PERF_TYPE_SOFTWARE, event_id, nr, &data, regs);
6709 6710 6711 6712 6713 6714 6715 6716 6717 6718 6719 6720
}

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);
6721 6722

	perf_swevent_put_recursion_context(rctx);
6723
fail:
6724
	preempt_enable_notrace();
6725 6726
}

6727
static void perf_swevent_read(struct perf_event *event)
6728 6729 6730
{
}

P
Peter Zijlstra 已提交
6731
static int perf_swevent_add(struct perf_event *event, int flags)
6732
{
6733
	struct swevent_htable *swhash = this_cpu_ptr(&swevent_htable);
6734
	struct hw_perf_event *hwc = &event->hw;
6735 6736
	struct hlist_head *head;

6737
	if (is_sampling_event(event)) {
6738
		hwc->last_period = hwc->sample_period;
6739
		perf_swevent_set_period(event);
6740
	}
6741

P
Peter Zijlstra 已提交
6742 6743
	hwc->state = !(flags & PERF_EF_START);

6744
	head = find_swevent_head(swhash, event);
P
Peter Zijlstra 已提交
6745
	if (WARN_ON_ONCE(!head))
6746 6747 6748
		return -EINVAL;

	hlist_add_head_rcu(&event->hlist_entry, head);
6749
	perf_event_update_userpage(event);
6750

6751 6752 6753
	return 0;
}

P
Peter Zijlstra 已提交
6754
static void perf_swevent_del(struct perf_event *event, int flags)
6755
{
6756
	hlist_del_rcu(&event->hlist_entry);
6757 6758
}

P
Peter Zijlstra 已提交
6759
static void perf_swevent_start(struct perf_event *event, int flags)
6760
{
P
Peter Zijlstra 已提交
6761
	event->hw.state = 0;
6762
}
I
Ingo Molnar 已提交
6763

P
Peter Zijlstra 已提交
6764
static void perf_swevent_stop(struct perf_event *event, int flags)
6765
{
P
Peter Zijlstra 已提交
6766
	event->hw.state = PERF_HES_STOPPED;
6767 6768
}

6769 6770
/* Deref the hlist from the update side */
static inline struct swevent_hlist *
6771
swevent_hlist_deref(struct swevent_htable *swhash)
6772
{
6773 6774
	return rcu_dereference_protected(swhash->swevent_hlist,
					 lockdep_is_held(&swhash->hlist_mutex));
6775 6776
}

6777
static void swevent_hlist_release(struct swevent_htable *swhash)
6778
{
6779
	struct swevent_hlist *hlist = swevent_hlist_deref(swhash);
6780

6781
	if (!hlist)
6782 6783
		return;

6784
	RCU_INIT_POINTER(swhash->swevent_hlist, NULL);
6785
	kfree_rcu(hlist, rcu_head);
6786 6787
}

6788
static void swevent_hlist_put_cpu(int cpu)
6789
{
6790
	struct swevent_htable *swhash = &per_cpu(swevent_htable, cpu);
6791

6792
	mutex_lock(&swhash->hlist_mutex);
6793

6794 6795
	if (!--swhash->hlist_refcount)
		swevent_hlist_release(swhash);
6796

6797
	mutex_unlock(&swhash->hlist_mutex);
6798 6799
}

6800
static void swevent_hlist_put(void)
6801 6802 6803 6804
{
	int cpu;

	for_each_possible_cpu(cpu)
6805
		swevent_hlist_put_cpu(cpu);
6806 6807
}

6808
static int swevent_hlist_get_cpu(int cpu)
6809
{
6810
	struct swevent_htable *swhash = &per_cpu(swevent_htable, cpu);
6811 6812
	int err = 0;

6813 6814
	mutex_lock(&swhash->hlist_mutex);
	if (!swevent_hlist_deref(swhash) && cpu_online(cpu)) {
6815 6816 6817 6818 6819 6820 6821
		struct swevent_hlist *hlist;

		hlist = kzalloc(sizeof(*hlist), GFP_KERNEL);
		if (!hlist) {
			err = -ENOMEM;
			goto exit;
		}
6822
		rcu_assign_pointer(swhash->swevent_hlist, hlist);
6823
	}
6824
	swhash->hlist_refcount++;
P
Peter Zijlstra 已提交
6825
exit:
6826
	mutex_unlock(&swhash->hlist_mutex);
6827 6828 6829 6830

	return err;
}

6831
static int swevent_hlist_get(void)
6832
{
6833
	int err, cpu, failed_cpu;
6834 6835 6836

	get_online_cpus();
	for_each_possible_cpu(cpu) {
6837
		err = swevent_hlist_get_cpu(cpu);
6838 6839 6840 6841 6842 6843 6844 6845
		if (err) {
			failed_cpu = cpu;
			goto fail;
		}
	}
	put_online_cpus();

	return 0;
P
Peter Zijlstra 已提交
6846
fail:
6847 6848 6849
	for_each_possible_cpu(cpu) {
		if (cpu == failed_cpu)
			break;
6850
		swevent_hlist_put_cpu(cpu);
6851 6852 6853 6854 6855 6856
	}

	put_online_cpus();
	return err;
}

6857
struct static_key perf_swevent_enabled[PERF_COUNT_SW_MAX];
6858

6859 6860 6861
static void sw_perf_event_destroy(struct perf_event *event)
{
	u64 event_id = event->attr.config;
6862

6863 6864
	WARN_ON(event->parent);

6865
	static_key_slow_dec(&perf_swevent_enabled[event_id]);
6866
	swevent_hlist_put();
6867 6868 6869 6870
}

static int perf_swevent_init(struct perf_event *event)
{
6871
	u64 event_id = event->attr.config;
6872 6873 6874 6875

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

6876 6877 6878 6879 6880 6881
	/*
	 * no branch sampling for software events
	 */
	if (has_branch_stack(event))
		return -EOPNOTSUPP;

6882 6883 6884 6885 6886 6887 6888 6889 6890
	switch (event_id) {
	case PERF_COUNT_SW_CPU_CLOCK:
	case PERF_COUNT_SW_TASK_CLOCK:
		return -ENOENT;

	default:
		break;
	}

6891
	if (event_id >= PERF_COUNT_SW_MAX)
6892 6893 6894 6895 6896
		return -ENOENT;

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

6897
		err = swevent_hlist_get();
6898 6899 6900
		if (err)
			return err;

6901
		static_key_slow_inc(&perf_swevent_enabled[event_id]);
6902 6903 6904 6905 6906 6907 6908
		event->destroy = sw_perf_event_destroy;
	}

	return 0;
}

static struct pmu perf_swevent = {
6909
	.task_ctx_nr	= perf_sw_context,
6910

6911 6912
	.capabilities	= PERF_PMU_CAP_NO_NMI,

6913
	.event_init	= perf_swevent_init,
P
Peter Zijlstra 已提交
6914 6915 6916 6917
	.add		= perf_swevent_add,
	.del		= perf_swevent_del,
	.start		= perf_swevent_start,
	.stop		= perf_swevent_stop,
6918 6919 6920
	.read		= perf_swevent_read,
};

6921 6922
#ifdef CONFIG_EVENT_TRACING

6923 6924 6925 6926 6927
static int perf_tp_filter_match(struct perf_event *event,
				struct perf_sample_data *data)
{
	void *record = data->raw->data;

6928 6929 6930 6931
	/* only top level events have filters set */
	if (event->parent)
		event = event->parent;

6932 6933 6934 6935 6936 6937 6938 6939 6940
	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)
{
6941 6942
	if (event->hw.state & PERF_HES_STOPPED)
		return 0;
6943 6944 6945 6946
	/*
	 * All tracepoints are from kernel-space.
	 */
	if (event->attr.exclude_kernel)
6947 6948 6949 6950 6951 6952 6953 6954 6955
		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,
6956 6957
		   struct pt_regs *regs, struct hlist_head *head, int rctx,
		   struct task_struct *task)
6958 6959
{
	struct perf_sample_data data;
6960 6961
	struct perf_event *event;

6962 6963 6964 6965 6966
	struct perf_raw_record raw = {
		.size = entry_size,
		.data = record,
	};

6967
	perf_sample_data_init(&data, addr, 0);
6968 6969
	data.raw = &raw;

6970
	hlist_for_each_entry_rcu(event, head, hlist_entry) {
6971
		if (perf_tp_event_match(event, &data, regs))
6972
			perf_swevent_event(event, count, &data, regs);
6973
	}
6974

6975 6976 6977 6978 6979 6980 6981 6982 6983 6984 6985 6986 6987 6988 6989 6990 6991 6992 6993 6994 6995 6996 6997 6998 6999
	/*
	 * 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();
	}

7000
	perf_swevent_put_recursion_context(rctx);
7001 7002 7003
}
EXPORT_SYMBOL_GPL(perf_tp_event);

7004
static void tp_perf_event_destroy(struct perf_event *event)
7005
{
7006
	perf_trace_destroy(event);
7007 7008
}

7009
static int perf_tp_event_init(struct perf_event *event)
7010
{
7011 7012
	int err;

7013 7014 7015
	if (event->attr.type != PERF_TYPE_TRACEPOINT)
		return -ENOENT;

7016 7017 7018 7019 7020 7021
	/*
	 * no branch sampling for tracepoint events
	 */
	if (has_branch_stack(event))
		return -EOPNOTSUPP;

7022 7023
	err = perf_trace_init(event);
	if (err)
7024
		return err;
7025

7026
	event->destroy = tp_perf_event_destroy;
7027

7028 7029 7030 7031
	return 0;
}

static struct pmu perf_tracepoint = {
7032 7033
	.task_ctx_nr	= perf_sw_context,

7034
	.event_init	= perf_tp_event_init,
P
Peter Zijlstra 已提交
7035 7036 7037 7038
	.add		= perf_trace_add,
	.del		= perf_trace_del,
	.start		= perf_swevent_start,
	.stop		= perf_swevent_stop,
7039 7040 7041 7042 7043
	.read		= perf_swevent_read,
};

static inline void perf_tp_register(void)
{
P
Peter Zijlstra 已提交
7044
	perf_pmu_register(&perf_tracepoint, "tracepoint", PERF_TYPE_TRACEPOINT);
7045
}
L
Li Zefan 已提交
7046 7047 7048 7049 7050 7051 7052 7053 7054 7055 7056 7057 7058 7059 7060 7061 7062 7063 7064 7065 7066 7067 7068 7069

static int perf_event_set_filter(struct perf_event *event, void __user *arg)
{
	char *filter_str;
	int ret;

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

	filter_str = strndup_user(arg, PAGE_SIZE);
	if (IS_ERR(filter_str))
		return PTR_ERR(filter_str);

	ret = ftrace_profile_set_filter(event, event->attr.config, filter_str);

	kfree(filter_str);
	return ret;
}

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

7070 7071 7072 7073 7074 7075 7076 7077 7078 7079
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;

7080 7081
	if (!(event->tp_event->flags & TRACE_EVENT_FL_UKPROBE))
		/* bpf programs can only be attached to u/kprobes */
7082 7083 7084 7085 7086 7087
		return -EINVAL;

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

7088
	if (prog->type != BPF_PROG_TYPE_KPROBE) {
7089 7090 7091 7092 7093 7094 7095 7096 7097 7098 7099 7100 7101 7102 7103 7104 7105 7106 7107 7108 7109 7110 7111 7112
		/* 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);
	}
}

7113
#else
L
Li Zefan 已提交
7114

7115
static inline void perf_tp_register(void)
7116 7117
{
}
L
Li Zefan 已提交
7118 7119 7120 7121 7122 7123 7124 7125 7126 7127

static int perf_event_set_filter(struct perf_event *event, void __user *arg)
{
	return -ENOENT;
}

static void perf_event_free_filter(struct perf_event *event)
{
}

7128 7129 7130 7131 7132 7133 7134 7135
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)
{
}
7136
#endif /* CONFIG_EVENT_TRACING */
7137

7138
#ifdef CONFIG_HAVE_HW_BREAKPOINT
7139
void perf_bp_event(struct perf_event *bp, void *data)
7140
{
7141 7142 7143
	struct perf_sample_data sample;
	struct pt_regs *regs = data;

7144
	perf_sample_data_init(&sample, bp->attr.bp_addr, 0);
7145

P
Peter Zijlstra 已提交
7146
	if (!bp->hw.state && !perf_exclude_event(bp, regs))
7147
		perf_swevent_event(bp, 1, &sample, regs);
7148 7149 7150
}
#endif

7151 7152 7153
/*
 * hrtimer based swevent callback
 */
7154

7155
static enum hrtimer_restart perf_swevent_hrtimer(struct hrtimer *hrtimer)
7156
{
7157 7158 7159 7160 7161
	enum hrtimer_restart ret = HRTIMER_RESTART;
	struct perf_sample_data data;
	struct pt_regs *regs;
	struct perf_event *event;
	u64 period;
7162

7163
	event = container_of(hrtimer, struct perf_event, hw.hrtimer);
P
Peter Zijlstra 已提交
7164 7165 7166 7167

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

7168
	event->pmu->read(event);
7169

7170
	perf_sample_data_init(&data, 0, event->hw.last_period);
7171 7172 7173
	regs = get_irq_regs();

	if (regs && !perf_exclude_event(event, regs)) {
7174
		if (!(event->attr.exclude_idle && is_idle_task(current)))
7175
			if (__perf_event_overflow(event, 1, &data, regs))
7176 7177
				ret = HRTIMER_NORESTART;
	}
7178

7179 7180
	period = max_t(u64, 10000, event->hw.sample_period);
	hrtimer_forward_now(hrtimer, ns_to_ktime(period));
7181

7182
	return ret;
7183 7184
}

7185
static void perf_swevent_start_hrtimer(struct perf_event *event)
7186
{
7187
	struct hw_perf_event *hwc = &event->hw;
7188 7189 7190 7191
	s64 period;

	if (!is_sampling_event(event))
		return;
7192

7193 7194 7195 7196
	period = local64_read(&hwc->period_left);
	if (period) {
		if (period < 0)
			period = 10000;
P
Peter Zijlstra 已提交
7197

7198 7199 7200 7201
		local64_set(&hwc->period_left, 0);
	} else {
		period = max_t(u64, 10000, hwc->sample_period);
	}
7202 7203
	hrtimer_start(&hwc->hrtimer, ns_to_ktime(period),
		      HRTIMER_MODE_REL_PINNED);
7204
}
7205 7206

static void perf_swevent_cancel_hrtimer(struct perf_event *event)
7207
{
7208 7209
	struct hw_perf_event *hwc = &event->hw;

7210
	if (is_sampling_event(event)) {
7211
		ktime_t remaining = hrtimer_get_remaining(&hwc->hrtimer);
P
Peter Zijlstra 已提交
7212
		local64_set(&hwc->period_left, ktime_to_ns(remaining));
7213 7214 7215

		hrtimer_cancel(&hwc->hrtimer);
	}
7216 7217
}

P
Peter Zijlstra 已提交
7218 7219 7220 7221 7222 7223 7224 7225 7226 7227 7228 7229 7230 7231 7232 7233 7234 7235 7236 7237
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);
7238
		hwc->last_period = hwc->sample_period;
P
Peter Zijlstra 已提交
7239 7240 7241 7242
		event->attr.freq = 0;
	}
}

7243 7244 7245 7246 7247
/*
 * Software event: cpu wall time clock
 */

static void cpu_clock_event_update(struct perf_event *event)
7248
{
7249 7250 7251
	s64 prev;
	u64 now;

P
Peter Zijlstra 已提交
7252
	now = local_clock();
7253 7254
	prev = local64_xchg(&event->hw.prev_count, now);
	local64_add(now - prev, &event->count);
7255 7256
}

P
Peter Zijlstra 已提交
7257
static void cpu_clock_event_start(struct perf_event *event, int flags)
7258
{
P
Peter Zijlstra 已提交
7259
	local64_set(&event->hw.prev_count, local_clock());
7260 7261 7262
	perf_swevent_start_hrtimer(event);
}

P
Peter Zijlstra 已提交
7263
static void cpu_clock_event_stop(struct perf_event *event, int flags)
7264
{
7265 7266 7267
	perf_swevent_cancel_hrtimer(event);
	cpu_clock_event_update(event);
}
7268

P
Peter Zijlstra 已提交
7269 7270 7271 7272
static int cpu_clock_event_add(struct perf_event *event, int flags)
{
	if (flags & PERF_EF_START)
		cpu_clock_event_start(event, flags);
7273
	perf_event_update_userpage(event);
P
Peter Zijlstra 已提交
7274 7275 7276 7277 7278 7279 7280 7281 7282

	return 0;
}

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

7283 7284 7285 7286
static void cpu_clock_event_read(struct perf_event *event)
{
	cpu_clock_event_update(event);
}
7287

7288 7289 7290 7291 7292 7293 7294 7295
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;

7296 7297 7298 7299 7300 7301
	/*
	 * no branch sampling for software events
	 */
	if (has_branch_stack(event))
		return -EOPNOTSUPP;

P
Peter Zijlstra 已提交
7302 7303
	perf_swevent_init_hrtimer(event);

7304
	return 0;
7305 7306
}

7307
static struct pmu perf_cpu_clock = {
7308 7309
	.task_ctx_nr	= perf_sw_context,

7310 7311
	.capabilities	= PERF_PMU_CAP_NO_NMI,

7312
	.event_init	= cpu_clock_event_init,
P
Peter Zijlstra 已提交
7313 7314 7315 7316
	.add		= cpu_clock_event_add,
	.del		= cpu_clock_event_del,
	.start		= cpu_clock_event_start,
	.stop		= cpu_clock_event_stop,
7317 7318 7319 7320 7321 7322 7323 7324
	.read		= cpu_clock_event_read,
};

/*
 * Software event: task time clock
 */

static void task_clock_event_update(struct perf_event *event, u64 now)
7325
{
7326 7327
	u64 prev;
	s64 delta;
7328

7329 7330 7331 7332
	prev = local64_xchg(&event->hw.prev_count, now);
	delta = now - prev;
	local64_add(delta, &event->count);
}
7333

P
Peter Zijlstra 已提交
7334
static void task_clock_event_start(struct perf_event *event, int flags)
7335
{
P
Peter Zijlstra 已提交
7336
	local64_set(&event->hw.prev_count, event->ctx->time);
7337 7338 7339
	perf_swevent_start_hrtimer(event);
}

P
Peter Zijlstra 已提交
7340
static void task_clock_event_stop(struct perf_event *event, int flags)
7341 7342 7343
{
	perf_swevent_cancel_hrtimer(event);
	task_clock_event_update(event, event->ctx->time);
P
Peter Zijlstra 已提交
7344 7345 7346 7347 7348 7349
}

static int task_clock_event_add(struct perf_event *event, int flags)
{
	if (flags & PERF_EF_START)
		task_clock_event_start(event, flags);
7350
	perf_event_update_userpage(event);
7351

P
Peter Zijlstra 已提交
7352 7353 7354 7355 7356 7357
	return 0;
}

static void task_clock_event_del(struct perf_event *event, int flags)
{
	task_clock_event_stop(event, PERF_EF_UPDATE);
7358 7359 7360 7361
}

static void task_clock_event_read(struct perf_event *event)
{
7362 7363 7364
	u64 now = perf_clock();
	u64 delta = now - event->ctx->timestamp;
	u64 time = event->ctx->time + delta;
7365 7366 7367 7368 7369

	task_clock_event_update(event, time);
}

static int task_clock_event_init(struct perf_event *event)
L
Li Zefan 已提交
7370
{
7371 7372 7373 7374 7375 7376
	if (event->attr.type != PERF_TYPE_SOFTWARE)
		return -ENOENT;

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

7377 7378 7379 7380 7381 7382
	/*
	 * no branch sampling for software events
	 */
	if (has_branch_stack(event))
		return -EOPNOTSUPP;

P
Peter Zijlstra 已提交
7383 7384
	perf_swevent_init_hrtimer(event);

7385
	return 0;
L
Li Zefan 已提交
7386 7387
}

7388
static struct pmu perf_task_clock = {
7389 7390
	.task_ctx_nr	= perf_sw_context,

7391 7392
	.capabilities	= PERF_PMU_CAP_NO_NMI,

7393
	.event_init	= task_clock_event_init,
P
Peter Zijlstra 已提交
7394 7395 7396 7397
	.add		= task_clock_event_add,
	.del		= task_clock_event_del,
	.start		= task_clock_event_start,
	.stop		= task_clock_event_stop,
7398 7399
	.read		= task_clock_event_read,
};
L
Li Zefan 已提交
7400

P
Peter Zijlstra 已提交
7401
static void perf_pmu_nop_void(struct pmu *pmu)
7402 7403
{
}
L
Li Zefan 已提交
7404

7405 7406 7407 7408
static void perf_pmu_nop_txn(struct pmu *pmu, unsigned int flags)
{
}

P
Peter Zijlstra 已提交
7409
static int perf_pmu_nop_int(struct pmu *pmu)
L
Li Zefan 已提交
7410
{
P
Peter Zijlstra 已提交
7411
	return 0;
L
Li Zefan 已提交
7412 7413
}

7414
static DEFINE_PER_CPU(unsigned int, nop_txn_flags);
7415 7416

static void perf_pmu_start_txn(struct pmu *pmu, unsigned int flags)
L
Li Zefan 已提交
7417
{
7418 7419 7420 7421 7422
	__this_cpu_write(nop_txn_flags, flags);

	if (flags & ~PERF_PMU_TXN_ADD)
		return;

P
Peter Zijlstra 已提交
7423
	perf_pmu_disable(pmu);
L
Li Zefan 已提交
7424 7425
}

P
Peter Zijlstra 已提交
7426 7427
static int perf_pmu_commit_txn(struct pmu *pmu)
{
7428 7429 7430 7431 7432 7433 7434
	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
7435 7436 7437
	perf_pmu_enable(pmu);
	return 0;
}
7438

P
Peter Zijlstra 已提交
7439
static void perf_pmu_cancel_txn(struct pmu *pmu)
7440
{
7441 7442 7443 7444 7445 7446 7447
	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
7448
	perf_pmu_enable(pmu);
7449 7450
}

7451 7452
static int perf_event_idx_default(struct perf_event *event)
{
7453
	return 0;
7454 7455
}

P
Peter Zijlstra 已提交
7456 7457 7458 7459
/*
 * Ensures all contexts with the same task_ctx_nr have the same
 * pmu_cpu_context too.
 */
7460
static struct perf_cpu_context __percpu *find_pmu_context(int ctxn)
7461
{
P
Peter Zijlstra 已提交
7462
	struct pmu *pmu;
7463

P
Peter Zijlstra 已提交
7464 7465
	if (ctxn < 0)
		return NULL;
7466

P
Peter Zijlstra 已提交
7467 7468 7469 7470
	list_for_each_entry(pmu, &pmus, entry) {
		if (pmu->task_ctx_nr == ctxn)
			return pmu->pmu_cpu_context;
	}
7471

P
Peter Zijlstra 已提交
7472
	return NULL;
7473 7474
}

7475
static void update_pmu_context(struct pmu *pmu, struct pmu *old_pmu)
7476
{
7477 7478 7479 7480 7481 7482 7483
	int cpu;

	for_each_possible_cpu(cpu) {
		struct perf_cpu_context *cpuctx;

		cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);

7484 7485
		if (cpuctx->unique_pmu == old_pmu)
			cpuctx->unique_pmu = pmu;
7486 7487 7488 7489 7490 7491
	}
}

static void free_pmu_context(struct pmu *pmu)
{
	struct pmu *i;
7492

P
Peter Zijlstra 已提交
7493
	mutex_lock(&pmus_lock);
7494
	/*
P
Peter Zijlstra 已提交
7495
	 * Like a real lame refcount.
7496
	 */
7497 7498 7499
	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
7500
			goto out;
7501
		}
P
Peter Zijlstra 已提交
7502
	}
7503

7504
	free_percpu(pmu->pmu_cpu_context);
P
Peter Zijlstra 已提交
7505 7506
out:
	mutex_unlock(&pmus_lock);
7507
}
P
Peter Zijlstra 已提交
7508
static struct idr pmu_idr;
7509

P
Peter Zijlstra 已提交
7510 7511 7512 7513 7514 7515 7516
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);
}
7517
static DEVICE_ATTR_RO(type);
P
Peter Zijlstra 已提交
7518

7519 7520 7521 7522 7523 7524 7525 7526 7527 7528
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);
}

7529 7530
static DEFINE_MUTEX(mux_interval_mutex);

7531 7532 7533 7534 7535 7536 7537 7538 7539 7540 7541 7542 7543 7544 7545 7546 7547 7548 7549
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;

7550
	mutex_lock(&mux_interval_mutex);
7551 7552 7553
	pmu->hrtimer_interval_ms = timer;

	/* update all cpuctx for this PMU */
7554 7555
	get_online_cpus();
	for_each_online_cpu(cpu) {
7556 7557 7558 7559
		struct perf_cpu_context *cpuctx;
		cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
		cpuctx->hrtimer_interval = ns_to_ktime(NSEC_PER_MSEC * timer);

7560 7561
		cpu_function_call(cpu,
			(remote_function_f)perf_mux_hrtimer_restart, cpuctx);
7562
	}
7563 7564
	put_online_cpus();
	mutex_unlock(&mux_interval_mutex);
7565 7566 7567

	return count;
}
7568
static DEVICE_ATTR_RW(perf_event_mux_interval_ms);
7569

7570 7571 7572 7573
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
7574
};
7575
ATTRIBUTE_GROUPS(pmu_dev);
P
Peter Zijlstra 已提交
7576 7577 7578 7579

static int pmu_bus_running;
static struct bus_type pmu_bus = {
	.name		= "event_source",
7580
	.dev_groups	= pmu_dev_groups,
P
Peter Zijlstra 已提交
7581 7582 7583 7584 7585 7586 7587 7588 7589 7590 7591 7592 7593 7594 7595
};

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;

7596
	pmu->dev->groups = pmu->attr_groups;
P
Peter Zijlstra 已提交
7597 7598 7599 7600 7601 7602 7603 7604 7605 7606 7607 7608 7609 7610 7611 7612 7613 7614 7615 7616
	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;

out:
	return ret;

free_dev:
	put_device(pmu->dev);
	goto out;
}

7617
static struct lock_class_key cpuctx_mutex;
7618
static struct lock_class_key cpuctx_lock;
7619

7620
int perf_pmu_register(struct pmu *pmu, const char *name, int type)
7621
{
P
Peter Zijlstra 已提交
7622
	int cpu, ret;
7623

7624
	mutex_lock(&pmus_lock);
P
Peter Zijlstra 已提交
7625 7626 7627 7628
	ret = -ENOMEM;
	pmu->pmu_disable_count = alloc_percpu(int);
	if (!pmu->pmu_disable_count)
		goto unlock;
7629

P
Peter Zijlstra 已提交
7630 7631 7632 7633 7634 7635
	pmu->type = -1;
	if (!name)
		goto skip_type;
	pmu->name = name;

	if (type < 0) {
T
Tejun Heo 已提交
7636 7637 7638
		type = idr_alloc(&pmu_idr, pmu, PERF_TYPE_MAX, 0, GFP_KERNEL);
		if (type < 0) {
			ret = type;
P
Peter Zijlstra 已提交
7639 7640 7641 7642 7643
			goto free_pdc;
		}
	}
	pmu->type = type;

P
Peter Zijlstra 已提交
7644 7645 7646 7647 7648 7649
	if (pmu_bus_running) {
		ret = pmu_dev_alloc(pmu);
		if (ret)
			goto free_idr;
	}

P
Peter Zijlstra 已提交
7650
skip_type:
P
Peter Zijlstra 已提交
7651 7652 7653
	pmu->pmu_cpu_context = find_pmu_context(pmu->task_ctx_nr);
	if (pmu->pmu_cpu_context)
		goto got_cpu_context;
7654

W
Wei Yongjun 已提交
7655
	ret = -ENOMEM;
P
Peter Zijlstra 已提交
7656 7657
	pmu->pmu_cpu_context = alloc_percpu(struct perf_cpu_context);
	if (!pmu->pmu_cpu_context)
P
Peter Zijlstra 已提交
7658
		goto free_dev;
7659

P
Peter Zijlstra 已提交
7660 7661 7662 7663
	for_each_possible_cpu(cpu) {
		struct perf_cpu_context *cpuctx;

		cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
7664
		__perf_event_init_context(&cpuctx->ctx);
7665
		lockdep_set_class(&cpuctx->ctx.mutex, &cpuctx_mutex);
7666
		lockdep_set_class(&cpuctx->ctx.lock, &cpuctx_lock);
P
Peter Zijlstra 已提交
7667
		cpuctx->ctx.pmu = pmu;
7668

7669
		__perf_mux_hrtimer_init(cpuctx, cpu);
7670

7671
		cpuctx->unique_pmu = pmu;
P
Peter Zijlstra 已提交
7672
	}
7673

P
Peter Zijlstra 已提交
7674
got_cpu_context:
P
Peter Zijlstra 已提交
7675 7676 7677 7678 7679 7680 7681 7682 7683 7684 7685
	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 {
7686
			pmu->start_txn  = perf_pmu_nop_txn;
P
Peter Zijlstra 已提交
7687 7688
			pmu->commit_txn = perf_pmu_nop_int;
			pmu->cancel_txn = perf_pmu_nop_void;
7689
		}
7690
	}
7691

P
Peter Zijlstra 已提交
7692 7693 7694 7695 7696
	if (!pmu->pmu_enable) {
		pmu->pmu_enable  = perf_pmu_nop_void;
		pmu->pmu_disable = perf_pmu_nop_void;
	}

7697 7698 7699
	if (!pmu->event_idx)
		pmu->event_idx = perf_event_idx_default;

7700
	list_add_rcu(&pmu->entry, &pmus);
7701
	atomic_set(&pmu->exclusive_cnt, 0);
P
Peter Zijlstra 已提交
7702 7703
	ret = 0;
unlock:
7704 7705
	mutex_unlock(&pmus_lock);

P
Peter Zijlstra 已提交
7706
	return ret;
P
Peter Zijlstra 已提交
7707

P
Peter Zijlstra 已提交
7708 7709 7710 7711
free_dev:
	device_del(pmu->dev);
	put_device(pmu->dev);

P
Peter Zijlstra 已提交
7712 7713 7714 7715
free_idr:
	if (pmu->type >= PERF_TYPE_MAX)
		idr_remove(&pmu_idr, pmu->type);

P
Peter Zijlstra 已提交
7716 7717 7718
free_pdc:
	free_percpu(pmu->pmu_disable_count);
	goto unlock;
7719
}
7720
EXPORT_SYMBOL_GPL(perf_pmu_register);
7721

7722
void perf_pmu_unregister(struct pmu *pmu)
7723
{
7724 7725 7726
	mutex_lock(&pmus_lock);
	list_del_rcu(&pmu->entry);
	mutex_unlock(&pmus_lock);
7727

7728
	/*
P
Peter Zijlstra 已提交
7729 7730
	 * We dereference the pmu list under both SRCU and regular RCU, so
	 * synchronize against both of those.
7731
	 */
7732
	synchronize_srcu(&pmus_srcu);
P
Peter Zijlstra 已提交
7733
	synchronize_rcu();
7734

P
Peter Zijlstra 已提交
7735
	free_percpu(pmu->pmu_disable_count);
P
Peter Zijlstra 已提交
7736 7737
	if (pmu->type >= PERF_TYPE_MAX)
		idr_remove(&pmu_idr, pmu->type);
P
Peter Zijlstra 已提交
7738 7739
	device_del(pmu->dev);
	put_device(pmu->dev);
7740
	free_pmu_context(pmu);
7741
}
7742
EXPORT_SYMBOL_GPL(perf_pmu_unregister);
7743

7744 7745
static int perf_try_init_event(struct pmu *pmu, struct perf_event *event)
{
P
Peter Zijlstra 已提交
7746
	struct perf_event_context *ctx = NULL;
7747 7748 7749 7750
	int ret;

	if (!try_module_get(pmu->module))
		return -ENODEV;
P
Peter Zijlstra 已提交
7751 7752

	if (event->group_leader != event) {
7753 7754 7755 7756 7757 7758
		/*
		 * 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
7759 7760 7761
		BUG_ON(!ctx);
	}

7762 7763
	event->pmu = pmu;
	ret = pmu->event_init(event);
P
Peter Zijlstra 已提交
7764 7765 7766 7767

	if (ctx)
		perf_event_ctx_unlock(event->group_leader, ctx);

7768 7769 7770 7771 7772 7773
	if (ret)
		module_put(pmu->module);

	return ret;
}

7774
static struct pmu *perf_init_event(struct perf_event *event)
7775 7776 7777
{
	struct pmu *pmu = NULL;
	int idx;
7778
	int ret;
7779 7780

	idx = srcu_read_lock(&pmus_srcu);
P
Peter Zijlstra 已提交
7781 7782 7783 7784

	rcu_read_lock();
	pmu = idr_find(&pmu_idr, event->attr.type);
	rcu_read_unlock();
7785
	if (pmu) {
7786
		ret = perf_try_init_event(pmu, event);
7787 7788
		if (ret)
			pmu = ERR_PTR(ret);
P
Peter Zijlstra 已提交
7789
		goto unlock;
7790
	}
P
Peter Zijlstra 已提交
7791

7792
	list_for_each_entry_rcu(pmu, &pmus, entry) {
7793
		ret = perf_try_init_event(pmu, event);
7794
		if (!ret)
P
Peter Zijlstra 已提交
7795
			goto unlock;
7796

7797 7798
		if (ret != -ENOENT) {
			pmu = ERR_PTR(ret);
P
Peter Zijlstra 已提交
7799
			goto unlock;
7800
		}
7801
	}
P
Peter Zijlstra 已提交
7802 7803
	pmu = ERR_PTR(-ENOENT);
unlock:
7804
	srcu_read_unlock(&pmus_srcu, idx);
7805

7806
	return pmu;
7807 7808
}

7809 7810 7811 7812 7813 7814 7815 7816 7817
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));
}

7818 7819
static void account_event(struct perf_event *event)
{
7820 7821
	bool inc = false;

7822 7823 7824
	if (event->parent)
		return;

7825
	if (event->attach_state & PERF_ATTACH_TASK)
7826
		inc = true;
7827 7828 7829 7830 7831 7832
	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);
7833 7834 7835 7836
	if (event->attr.freq) {
		if (atomic_inc_return(&nr_freq_events) == 1)
			tick_nohz_full_kick_all();
	}
7837 7838
	if (event->attr.context_switch) {
		atomic_inc(&nr_switch_events);
7839
		inc = true;
7840
	}
7841
	if (has_branch_stack(event))
7842
		inc = true;
7843
	if (is_cgroup_event(event))
7844 7845
		inc = true;

7846 7847 7848 7849 7850 7851 7852 7853 7854 7855 7856 7857 7858 7859 7860 7861 7862 7863 7864 7865 7866 7867
	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:
7868 7869

	account_event_cpu(event, event->cpu);
7870 7871
}

T
Thomas Gleixner 已提交
7872
/*
7873
 * Allocate and initialize a event structure
T
Thomas Gleixner 已提交
7874
 */
7875
static struct perf_event *
7876
perf_event_alloc(struct perf_event_attr *attr, int cpu,
7877 7878 7879
		 struct task_struct *task,
		 struct perf_event *group_leader,
		 struct perf_event *parent_event,
7880
		 perf_overflow_handler_t overflow_handler,
7881
		 void *context, int cgroup_fd)
T
Thomas Gleixner 已提交
7882
{
P
Peter Zijlstra 已提交
7883
	struct pmu *pmu;
7884 7885
	struct perf_event *event;
	struct hw_perf_event *hwc;
7886
	long err = -EINVAL;
T
Thomas Gleixner 已提交
7887

7888 7889 7890 7891 7892
	if ((unsigned)cpu >= nr_cpu_ids) {
		if (!task || cpu != -1)
			return ERR_PTR(-EINVAL);
	}

7893
	event = kzalloc(sizeof(*event), GFP_KERNEL);
7894
	if (!event)
7895
		return ERR_PTR(-ENOMEM);
T
Thomas Gleixner 已提交
7896

7897
	/*
7898
	 * Single events are their own group leaders, with an
7899 7900 7901
	 * empty sibling list:
	 */
	if (!group_leader)
7902
		group_leader = event;
7903

7904 7905
	mutex_init(&event->child_mutex);
	INIT_LIST_HEAD(&event->child_list);
7906

7907 7908 7909
	INIT_LIST_HEAD(&event->group_entry);
	INIT_LIST_HEAD(&event->event_entry);
	INIT_LIST_HEAD(&event->sibling_list);
7910
	INIT_LIST_HEAD(&event->rb_entry);
7911
	INIT_LIST_HEAD(&event->active_entry);
7912 7913
	INIT_HLIST_NODE(&event->hlist_entry);

7914

7915
	init_waitqueue_head(&event->waitq);
7916
	init_irq_work(&event->pending, perf_pending_event);
T
Thomas Gleixner 已提交
7917

7918
	mutex_init(&event->mmap_mutex);
7919

7920
	atomic_long_set(&event->refcount, 1);
7921 7922 7923 7924 7925
	event->cpu		= cpu;
	event->attr		= *attr;
	event->group_leader	= group_leader;
	event->pmu		= NULL;
	event->oncpu		= -1;
7926

7927
	event->parent		= parent_event;
7928

7929
	event->ns		= get_pid_ns(task_active_pid_ns(current));
7930
	event->id		= atomic64_inc_return(&perf_event_id);
7931

7932
	event->state		= PERF_EVENT_STATE_INACTIVE;
7933

7934 7935 7936
	if (task) {
		event->attach_state = PERF_ATTACH_TASK;
		/*
7937 7938 7939
		 * 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.
7940
		 */
7941
		event->hw.target = task;
7942 7943
	}

7944 7945 7946 7947
	event->clock = &local_clock;
	if (parent_event)
		event->clock = parent_event->clock;

7948
	if (!overflow_handler && parent_event) {
7949
		overflow_handler = parent_event->overflow_handler;
7950 7951
		context = parent_event->overflow_handler_context;
	}
7952

7953
	event->overflow_handler	= overflow_handler;
7954
	event->overflow_handler_context = context;
7955

J
Jiri Olsa 已提交
7956
	perf_event__state_init(event);
7957

7958
	pmu = NULL;
7959

7960
	hwc = &event->hw;
7961
	hwc->sample_period = attr->sample_period;
7962
	if (attr->freq && attr->sample_freq)
7963
		hwc->sample_period = 1;
7964
	hwc->last_period = hwc->sample_period;
7965

7966
	local64_set(&hwc->period_left, hwc->sample_period);
7967

7968
	/*
7969
	 * we currently do not support PERF_FORMAT_GROUP on inherited events
7970
	 */
7971
	if (attr->inherit && (attr->read_format & PERF_FORMAT_GROUP))
7972
		goto err_ns;
7973 7974 7975

	if (!has_branch_stack(event))
		event->attr.branch_sample_type = 0;
7976

7977 7978 7979 7980 7981 7982
	if (cgroup_fd != -1) {
		err = perf_cgroup_connect(cgroup_fd, event, attr, group_leader);
		if (err)
			goto err_ns;
	}

7983
	pmu = perf_init_event(event);
7984
	if (!pmu)
7985 7986
		goto err_ns;
	else if (IS_ERR(pmu)) {
7987
		err = PTR_ERR(pmu);
7988
		goto err_ns;
I
Ingo Molnar 已提交
7989
	}
7990

7991 7992 7993 7994
	err = exclusive_event_init(event);
	if (err)
		goto err_pmu;

7995
	if (!event->parent) {
7996 7997
		if (event->attr.sample_type & PERF_SAMPLE_CALLCHAIN) {
			err = get_callchain_buffers();
7998
			if (err)
7999
				goto err_per_task;
8000
		}
8001
	}
8002

8003
	return event;
8004

8005 8006 8007
err_per_task:
	exclusive_event_destroy(event);

8008 8009 8010
err_pmu:
	if (event->destroy)
		event->destroy(event);
8011
	module_put(pmu->module);
8012
err_ns:
8013 8014
	if (is_cgroup_event(event))
		perf_detach_cgroup(event);
8015 8016 8017 8018 8019
	if (event->ns)
		put_pid_ns(event->ns);
	kfree(event);

	return ERR_PTR(err);
T
Thomas Gleixner 已提交
8020 8021
}

8022 8023
static int perf_copy_attr(struct perf_event_attr __user *uattr,
			  struct perf_event_attr *attr)
8024 8025
{
	u32 size;
8026
	int ret;
8027 8028 8029 8030 8031 8032 8033 8034 8035 8036 8037 8038 8039 8040 8041 8042 8043 8044 8045 8046 8047 8048 8049 8050

	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,
8051 8052 8053
	 * 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.
8054 8055
	 */
	if (size > sizeof(*attr)) {
8056 8057 8058
		unsigned char __user *addr;
		unsigned char __user *end;
		unsigned char val;
8059

8060 8061
		addr = (void __user *)uattr + sizeof(*attr);
		end  = (void __user *)uattr + size;
8062

8063
		for (; addr < end; addr++) {
8064 8065 8066 8067 8068 8069
			ret = get_user(val, addr);
			if (ret)
				return ret;
			if (val)
				goto err_size;
		}
8070
		size = sizeof(*attr);
8071 8072 8073 8074 8075 8076
	}

	ret = copy_from_user(attr, uattr, size);
	if (ret)
		return -EFAULT;

8077
	if (attr->__reserved_1)
8078 8079 8080 8081 8082 8083 8084 8085
		return -EINVAL;

	if (attr->sample_type & ~(PERF_SAMPLE_MAX-1))
		return -EINVAL;

	if (attr->read_format & ~(PERF_FORMAT_MAX-1))
		return -EINVAL;

8086 8087 8088 8089 8090 8091 8092 8093 8094 8095 8096 8097 8098 8099 8100 8101 8102 8103 8104 8105 8106 8107 8108 8109 8110 8111 8112 8113
	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;
		}
8114 8115
		/* privileged levels capture (kernel, hv): check permissions */
		if ((mask & PERF_SAMPLE_BRANCH_PERM_PLM)
8116 8117
		    && perf_paranoid_kernel() && !capable(CAP_SYS_ADMIN))
			return -EACCES;
8118
	}
8119

8120
	if (attr->sample_type & PERF_SAMPLE_REGS_USER) {
8121
		ret = perf_reg_validate(attr->sample_regs_user);
8122 8123 8124 8125 8126 8127 8128 8129 8130 8131 8132 8133 8134 8135 8136 8137 8138 8139
		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;
	}
8140

8141 8142
	if (attr->sample_type & PERF_SAMPLE_REGS_INTR)
		ret = perf_reg_validate(attr->sample_regs_intr);
8143 8144 8145 8146 8147 8148 8149 8150 8151
out:
	return ret;

err_size:
	put_user(sizeof(*attr), &uattr->size);
	ret = -E2BIG;
	goto out;
}

8152 8153
static int
perf_event_set_output(struct perf_event *event, struct perf_event *output_event)
8154
{
8155
	struct ring_buffer *rb = NULL;
8156 8157
	int ret = -EINVAL;

8158
	if (!output_event)
8159 8160
		goto set;

8161 8162
	/* don't allow circular references */
	if (event == output_event)
8163 8164
		goto out;

8165 8166 8167 8168 8169 8170 8171
	/*
	 * Don't allow cross-cpu buffers
	 */
	if (output_event->cpu != event->cpu)
		goto out;

	/*
8172
	 * If its not a per-cpu rb, it must be the same task.
8173 8174 8175 8176
	 */
	if (output_event->cpu == -1 && output_event->ctx != event->ctx)
		goto out;

8177 8178 8179 8180 8181 8182
	/*
	 * Mixing clocks in the same buffer is trouble you don't need.
	 */
	if (output_event->clock != event->clock)
		goto out;

8183 8184 8185 8186 8187 8188 8189
	/*
	 * 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;

8190
set:
8191
	mutex_lock(&event->mmap_mutex);
8192 8193 8194
	/* Can't redirect output if we've got an active mmap() */
	if (atomic_read(&event->mmap_count))
		goto unlock;
8195

8196
	if (output_event) {
8197 8198 8199
		/* get the rb we want to redirect to */
		rb = ring_buffer_get(output_event);
		if (!rb)
8200
			goto unlock;
8201 8202
	}

8203
	ring_buffer_attach(event, rb);
8204

8205
	ret = 0;
8206 8207 8208
unlock:
	mutex_unlock(&event->mmap_mutex);

8209 8210 8211 8212
out:
	return ret;
}

P
Peter Zijlstra 已提交
8213 8214 8215 8216 8217 8218 8219 8220 8221
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);
}

8222 8223 8224 8225 8226 8227 8228 8229 8230 8231 8232 8233 8234 8235 8236 8237 8238 8239 8240 8241 8242 8243 8244 8245 8246 8247 8248 8249 8250 8251 8252 8253 8254 8255 8256 8257 8258
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
8259
/**
8260
 * sys_perf_event_open - open a performance event, associate it to a task/cpu
I
Ingo Molnar 已提交
8261
 *
8262
 * @attr_uptr:	event_id type attributes for monitoring/sampling
T
Thomas Gleixner 已提交
8263
 * @pid:		target pid
I
Ingo Molnar 已提交
8264
 * @cpu:		target cpu
8265
 * @group_fd:		group leader event fd
T
Thomas Gleixner 已提交
8266
 */
8267 8268
SYSCALL_DEFINE5(perf_event_open,
		struct perf_event_attr __user *, attr_uptr,
8269
		pid_t, pid, int, cpu, int, group_fd, unsigned long, flags)
T
Thomas Gleixner 已提交
8270
{
8271 8272
	struct perf_event *group_leader = NULL, *output_event = NULL;
	struct perf_event *event, *sibling;
8273
	struct perf_event_attr attr;
P
Peter Zijlstra 已提交
8274
	struct perf_event_context *ctx, *uninitialized_var(gctx);
8275
	struct file *event_file = NULL;
8276
	struct fd group = {NULL, 0};
M
Matt Helsley 已提交
8277
	struct task_struct *task = NULL;
8278
	struct pmu *pmu;
8279
	int event_fd;
8280
	int move_group = 0;
8281
	int err;
8282
	int f_flags = O_RDWR;
8283
	int cgroup_fd = -1;
T
Thomas Gleixner 已提交
8284

8285
	/* for future expandability... */
S
Stephane Eranian 已提交
8286
	if (flags & ~PERF_FLAG_ALL)
8287 8288
		return -EINVAL;

8289 8290 8291
	err = perf_copy_attr(attr_uptr, &attr);
	if (err)
		return err;
8292

8293 8294 8295 8296 8297
	if (!attr.exclude_kernel) {
		if (perf_paranoid_kernel() && !capable(CAP_SYS_ADMIN))
			return -EACCES;
	}

8298
	if (attr.freq) {
8299
		if (attr.sample_freq > sysctl_perf_event_sample_rate)
8300
			return -EINVAL;
8301 8302 8303
	} else {
		if (attr.sample_period & (1ULL << 63))
			return -EINVAL;
8304 8305
	}

S
Stephane Eranian 已提交
8306 8307 8308 8309 8310 8311 8312 8313 8314
	/*
	 * 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;

8315 8316 8317 8318
	if (flags & PERF_FLAG_FD_CLOEXEC)
		f_flags |= O_CLOEXEC;

	event_fd = get_unused_fd_flags(f_flags);
8319 8320 8321
	if (event_fd < 0)
		return event_fd;

8322
	if (group_fd != -1) {
8323 8324
		err = perf_fget_light(group_fd, &group);
		if (err)
8325
			goto err_fd;
8326
		group_leader = group.file->private_data;
8327 8328 8329 8330 8331 8332
		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
8333
	if (pid != -1 && !(flags & PERF_FLAG_PID_CGROUP)) {
8334 8335 8336 8337 8338 8339 8340
		task = find_lively_task_by_vpid(pid);
		if (IS_ERR(task)) {
			err = PTR_ERR(task);
			goto err_group_fd;
		}
	}

8341 8342 8343 8344 8345 8346
	if (task && group_leader &&
	    group_leader->attr.inherit != attr.inherit) {
		err = -EINVAL;
		goto err_task;
	}

8347 8348
	get_online_cpus();

8349 8350 8351
	if (flags & PERF_FLAG_PID_CGROUP)
		cgroup_fd = pid;

8352
	event = perf_event_alloc(&attr, cpu, task, group_leader, NULL,
8353
				 NULL, NULL, cgroup_fd);
8354 8355
	if (IS_ERR(event)) {
		err = PTR_ERR(event);
8356
		goto err_cpus;
8357 8358
	}

8359 8360 8361 8362 8363 8364 8365
	if (is_sampling_event(event)) {
		if (event->pmu->capabilities & PERF_PMU_CAP_NO_INTERRUPT) {
			err = -ENOTSUPP;
			goto err_alloc;
		}
	}

8366 8367
	account_event(event);

8368 8369 8370 8371 8372
	/*
	 * Special case software events and allow them to be part of
	 * any hardware group.
	 */
	pmu = event->pmu;
8373

8374 8375 8376 8377 8378 8379
	if (attr.use_clockid) {
		err = perf_event_set_clock(event, attr.clockid);
		if (err)
			goto err_alloc;
	}

8380 8381 8382 8383 8384 8385 8386 8387 8388 8389 8390 8391 8392 8393 8394 8395 8396 8397 8398 8399 8400 8401
	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;
		}
	}
8402 8403 8404 8405

	/*
	 * Get the target context (task or percpu):
	 */
8406
	ctx = find_get_context(pmu, task, event);
8407 8408
	if (IS_ERR(ctx)) {
		err = PTR_ERR(ctx);
8409
		goto err_alloc;
8410 8411
	}

8412 8413 8414 8415 8416
	if ((pmu->capabilities & PERF_PMU_CAP_EXCLUSIVE) && group_leader) {
		err = -EBUSY;
		goto err_context;
	}

8417 8418 8419 8420 8421
	if (task) {
		put_task_struct(task);
		task = NULL;
	}

I
Ingo Molnar 已提交
8422
	/*
8423
	 * Look up the group leader (we will attach this event to it):
8424
	 */
8425
	if (group_leader) {
8426
		err = -EINVAL;
8427 8428

		/*
I
Ingo Molnar 已提交
8429 8430 8431 8432
		 * Do not allow a recursive hierarchy (this new sibling
		 * becoming part of another group-sibling):
		 */
		if (group_leader->group_leader != group_leader)
8433
			goto err_context;
8434 8435 8436 8437 8438

		/* 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
8439 8440 8441
		/*
		 * Do not allow to attach to a group in a different
		 * task or CPU context:
8442
		 */
8443
		if (move_group) {
8444 8445 8446 8447 8448 8449 8450 8451 8452 8453 8454 8455 8456
			/*
			 * 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)
8457 8458 8459 8460 8461 8462
				goto err_context;
		} else {
			if (group_leader->ctx != ctx)
				goto err_context;
		}

8463 8464 8465
		/*
		 * Only a group leader can be exclusive or pinned
		 */
8466
		if (attr.exclusive || attr.pinned)
8467
			goto err_context;
8468 8469 8470 8471 8472
	}

	if (output_event) {
		err = perf_event_set_output(event, output_event);
		if (err)
8473
			goto err_context;
8474
	}
T
Thomas Gleixner 已提交
8475

8476 8477
	event_file = anon_inode_getfile("[perf_event]", &perf_fops, event,
					f_flags);
8478 8479
	if (IS_ERR(event_file)) {
		err = PTR_ERR(event_file);
8480
		goto err_context;
8481
	}
8482

8483
	if (move_group) {
P
Peter Zijlstra 已提交
8484
		gctx = group_leader->ctx;
8485
		mutex_lock_double(&gctx->mutex, &ctx->mutex);
8486 8487 8488 8489
		if (gctx->task == TASK_TOMBSTONE) {
			err = -ESRCH;
			goto err_locked;
		}
8490 8491 8492 8493
	} else {
		mutex_lock(&ctx->mutex);
	}

8494 8495 8496 8497 8498
	if (ctx->task == TASK_TOMBSTONE) {
		err = -ESRCH;
		goto err_locked;
	}

P
Peter Zijlstra 已提交
8499 8500 8501 8502 8503
	if (!perf_event_validate_size(event)) {
		err = -E2BIG;
		goto err_locked;
	}

8504 8505 8506 8507 8508 8509 8510
	/*
	 * 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
8511

8512 8513 8514
		err = -EBUSY;
		goto err_locked;
	}
P
Peter Zijlstra 已提交
8515

8516 8517 8518
	WARN_ON_ONCE(ctx->parent_ctx);

	if (move_group) {
P
Peter Zijlstra 已提交
8519 8520 8521 8522
		/*
		 * See perf_event_ctx_lock() for comments on the details
		 * of swizzling perf_event::ctx.
		 */
8523
		perf_remove_from_context(group_leader, 0);
J
Jiri Olsa 已提交
8524

8525 8526
		list_for_each_entry(sibling, &group_leader->sibling_list,
				    group_entry) {
8527
			perf_remove_from_context(sibling, 0);
8528 8529 8530
			put_ctx(gctx);
		}

P
Peter Zijlstra 已提交
8531 8532 8533 8534
		/*
		 * Wait for everybody to stop referencing the events through
		 * the old lists, before installing it on new lists.
		 */
8535
		synchronize_rcu();
P
Peter Zijlstra 已提交
8536

8537 8538 8539 8540 8541 8542 8543 8544 8545 8546
		/*
		 * 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.
		 */
8547 8548
		list_for_each_entry(sibling, &group_leader->sibling_list,
				    group_entry) {
8549
			perf_event__state_init(sibling);
8550
			perf_install_in_context(ctx, sibling, sibling->cpu);
8551 8552
			get_ctx(ctx);
		}
8553 8554 8555 8556 8557 8558 8559 8560 8561

		/*
		 * 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);
8562

8563 8564 8565 8566 8567 8568
		/*
		 * Now that all events are installed in @ctx, nothing
		 * references @gctx anymore, so drop the last reference we have
		 * on it.
		 */
		put_ctx(gctx);
8569 8570
	}

8571 8572 8573 8574 8575 8576 8577 8578 8579
	/*
	 * 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
8580 8581
	event->owner = current;

8582
	perf_install_in_context(ctx, event, event->cpu);
8583
	perf_unpin_context(ctx);
P
Peter Zijlstra 已提交
8584

8585
	if (move_group)
P
Peter Zijlstra 已提交
8586
		mutex_unlock(&gctx->mutex);
8587
	mutex_unlock(&ctx->mutex);
8588

8589 8590
	put_online_cpus();

8591 8592 8593
	mutex_lock(&current->perf_event_mutex);
	list_add_tail(&event->owner_entry, &current->perf_event_list);
	mutex_unlock(&current->perf_event_mutex);
8594

8595 8596 8597 8598 8599 8600
	/*
	 * 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().
	 */
8601
	fdput(group);
8602 8603
	fd_install(event_fd, event_file);
	return event_fd;
T
Thomas Gleixner 已提交
8604

8605 8606 8607 8608 8609 8610
err_locked:
	if (move_group)
		mutex_unlock(&gctx->mutex);
	mutex_unlock(&ctx->mutex);
/* err_file: */
	fput(event_file);
8611
err_context:
8612
	perf_unpin_context(ctx);
8613
	put_ctx(ctx);
8614
err_alloc:
P
Peter Zijlstra 已提交
8615 8616 8617 8618 8619 8620
	/*
	 * 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);
8621
err_cpus:
8622
	put_online_cpus();
8623
err_task:
P
Peter Zijlstra 已提交
8624 8625
	if (task)
		put_task_struct(task);
8626
err_group_fd:
8627
	fdput(group);
8628 8629
err_fd:
	put_unused_fd(event_fd);
8630
	return err;
T
Thomas Gleixner 已提交
8631 8632
}

8633 8634 8635 8636 8637
/**
 * 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
8638
 * @task: task to profile (NULL for percpu)
8639 8640 8641
 */
struct perf_event *
perf_event_create_kernel_counter(struct perf_event_attr *attr, int cpu,
M
Matt Helsley 已提交
8642
				 struct task_struct *task,
8643 8644
				 perf_overflow_handler_t overflow_handler,
				 void *context)
8645 8646
{
	struct perf_event_context *ctx;
8647
	struct perf_event *event;
8648
	int err;
8649

8650 8651 8652
	/*
	 * Get the target context (task or percpu):
	 */
8653

8654
	event = perf_event_alloc(attr, cpu, task, NULL, NULL,
8655
				 overflow_handler, context, -1);
8656 8657 8658 8659
	if (IS_ERR(event)) {
		err = PTR_ERR(event);
		goto err;
	}
8660

8661
	/* Mark owner so we could distinguish it from user events. */
8662
	event->owner = TASK_TOMBSTONE;
8663

8664 8665
	account_event(event);

8666
	ctx = find_get_context(event->pmu, task, event);
8667 8668
	if (IS_ERR(ctx)) {
		err = PTR_ERR(ctx);
8669
		goto err_free;
8670
	}
8671 8672 8673

	WARN_ON_ONCE(ctx->parent_ctx);
	mutex_lock(&ctx->mutex);
8674 8675 8676 8677 8678
	if (ctx->task == TASK_TOMBSTONE) {
		err = -ESRCH;
		goto err_unlock;
	}

8679 8680
	if (!exclusive_event_installable(event, ctx)) {
		err = -EBUSY;
8681
		goto err_unlock;
8682 8683
	}

8684
	perf_install_in_context(ctx, event, cpu);
8685
	perf_unpin_context(ctx);
8686 8687 8688 8689
	mutex_unlock(&ctx->mutex);

	return event;

8690 8691 8692 8693
err_unlock:
	mutex_unlock(&ctx->mutex);
	perf_unpin_context(ctx);
	put_ctx(ctx);
8694 8695 8696
err_free:
	free_event(event);
err:
8697
	return ERR_PTR(err);
8698
}
8699
EXPORT_SYMBOL_GPL(perf_event_create_kernel_counter);
8700

8701 8702 8703 8704 8705 8706 8707 8708 8709 8710
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
8711 8712 8713 8714 8715
	/*
	 * See perf_event_ctx_lock() for comments on the details
	 * of swizzling perf_event::ctx.
	 */
	mutex_lock_double(&src_ctx->mutex, &dst_ctx->mutex);
8716 8717
	list_for_each_entry_safe(event, tmp, &src_ctx->event_list,
				 event_entry) {
8718
		perf_remove_from_context(event, 0);
8719
		unaccount_event_cpu(event, src_cpu);
8720
		put_ctx(src_ctx);
8721
		list_add(&event->migrate_entry, &events);
8722 8723
	}

8724 8725 8726
	/*
	 * Wait for the events to quiesce before re-instating them.
	 */
8727 8728
	synchronize_rcu();

8729 8730 8731 8732 8733 8734 8735 8736 8737 8738 8739 8740 8741 8742 8743 8744 8745 8746 8747 8748 8749 8750 8751 8752
	/*
	 * 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.
	 */
8753 8754
	list_for_each_entry_safe(event, tmp, &events, migrate_entry) {
		list_del(&event->migrate_entry);
8755 8756
		if (event->state >= PERF_EVENT_STATE_OFF)
			event->state = PERF_EVENT_STATE_INACTIVE;
8757
		account_event_cpu(event, dst_cpu);
8758 8759 8760 8761
		perf_install_in_context(dst_ctx, event, dst_cpu);
		get_ctx(dst_ctx);
	}
	mutex_unlock(&dst_ctx->mutex);
P
Peter Zijlstra 已提交
8762
	mutex_unlock(&src_ctx->mutex);
8763 8764 8765
}
EXPORT_SYMBOL_GPL(perf_pmu_migrate_context);

8766
static void sync_child_event(struct perf_event *child_event,
8767
			       struct task_struct *child)
8768
{
8769
	struct perf_event *parent_event = child_event->parent;
8770
	u64 child_val;
8771

8772 8773
	if (child_event->attr.inherit_stat)
		perf_event_read_event(child_event, child);
8774

P
Peter Zijlstra 已提交
8775
	child_val = perf_event_count(child_event);
8776 8777 8778 8779

	/*
	 * Add back the child's count to the parent's count:
	 */
8780
	atomic64_add(child_val, &parent_event->child_count);
8781 8782 8783 8784
	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);
8785 8786
}

8787
static void
8788 8789 8790
perf_event_exit_event(struct perf_event *child_event,
		      struct perf_event_context *child_ctx,
		      struct task_struct *child)
8791
{
8792 8793
	struct perf_event *parent_event = child_event->parent;

8794 8795 8796 8797 8798 8799 8800 8801 8802 8803 8804 8805
	/*
	 * 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.
	 */
8806 8807 8808
	raw_spin_lock_irq(&child_ctx->lock);
	WARN_ON_ONCE(child_ctx->is_active);

8809
	if (parent_event)
8810 8811
		perf_group_detach(child_event);
	list_del_event(child_event, child_ctx);
P
Peter Zijlstra 已提交
8812
	child_event->state = PERF_EVENT_STATE_EXIT; /* is_event_hup() */
8813
	raw_spin_unlock_irq(&child_ctx->lock);
8814

8815
	/*
8816
	 * Parent events are governed by their filedesc, retain them.
8817
	 */
8818
	if (!parent_event) {
8819
		perf_event_wakeup(child_event);
8820
		return;
8821
	}
8822 8823 8824 8825 8826 8827 8828 8829 8830 8831 8832 8833 8834 8835 8836 8837 8838 8839 8840 8841
	/*
	 * 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);
8842 8843
}

P
Peter Zijlstra 已提交
8844
static void perf_event_exit_task_context(struct task_struct *child, int ctxn)
8845
{
8846
	struct perf_event_context *child_ctx, *clone_ctx = NULL;
8847 8848 8849
	struct perf_event *child_event, *next;

	WARN_ON_ONCE(child != current);
8850

8851
	child_ctx = perf_pin_task_context(child, ctxn);
8852
	if (!child_ctx)
8853 8854
		return;

8855
	/*
8856 8857 8858 8859 8860 8861 8862 8863
	 * 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().
8864
	 */
8865
	mutex_lock(&child_ctx->mutex);
8866 8867

	/*
8868 8869 8870
	 * 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.
8871
	 */
8872
	raw_spin_lock_irq(&child_ctx->lock);
8873
	task_ctx_sched_out(__get_cpu_context(child_ctx), child_ctx);
8874

8875
	/*
8876 8877
	 * Now that the context is inactive, destroy the task <-> ctx relation
	 * and mark the context dead.
8878
	 */
8879 8880 8881 8882
	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 */
8883

8884
	clone_ctx = unclone_ctx(child_ctx);
8885
	raw_spin_unlock_irq(&child_ctx->lock);
P
Peter Zijlstra 已提交
8886

8887 8888
	if (clone_ctx)
		put_ctx(clone_ctx);
8889

P
Peter Zijlstra 已提交
8890
	/*
8891 8892 8893
	 * 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
8894
	 */
8895
	perf_event_task(child, child_ctx, 0);
8896

8897
	list_for_each_entry_safe(child_event, next, &child_ctx->event_list, event_entry)
8898
		perf_event_exit_event(child_event, child_ctx, child);
8899

8900 8901 8902
	mutex_unlock(&child_ctx->mutex);

	put_ctx(child_ctx);
8903 8904
}

P
Peter Zijlstra 已提交
8905 8906 8907 8908 8909
/*
 * When a child task exits, feed back event values to parent events.
 */
void perf_event_exit_task(struct task_struct *child)
{
P
Peter Zijlstra 已提交
8910
	struct perf_event *event, *tmp;
P
Peter Zijlstra 已提交
8911 8912
	int ctxn;

P
Peter Zijlstra 已提交
8913 8914 8915 8916 8917 8918 8919 8920 8921 8922
	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.
		 */
8923
		smp_store_release(&event->owner, NULL);
P
Peter Zijlstra 已提交
8924 8925 8926
	}
	mutex_unlock(&child->perf_event_mutex);

P
Peter Zijlstra 已提交
8927 8928
	for_each_task_context_nr(ctxn)
		perf_event_exit_task_context(child, ctxn);
J
Jiri Olsa 已提交
8929 8930 8931 8932 8933 8934 8935 8936

	/*
	 * 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
8937 8938
}

8939 8940 8941 8942 8943 8944 8945 8946 8947 8948 8949 8950
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);

8951
	put_event(parent);
8952

P
Peter Zijlstra 已提交
8953
	raw_spin_lock_irq(&ctx->lock);
8954
	perf_group_detach(event);
8955
	list_del_event(event, ctx);
P
Peter Zijlstra 已提交
8956
	raw_spin_unlock_irq(&ctx->lock);
8957 8958 8959
	free_event(event);
}

8960
/*
P
Peter Zijlstra 已提交
8961
 * Free an unexposed, unused context as created by inheritance by
P
Peter Zijlstra 已提交
8962
 * perf_event_init_task below, used by fork() in case of fail.
P
Peter Zijlstra 已提交
8963 8964 8965
 *
 * Not all locks are strictly required, but take them anyway to be nice and
 * help out with the lockdep assertions.
8966
 */
8967
void perf_event_free_task(struct task_struct *task)
8968
{
P
Peter Zijlstra 已提交
8969
	struct perf_event_context *ctx;
8970
	struct perf_event *event, *tmp;
P
Peter Zijlstra 已提交
8971
	int ctxn;
8972

P
Peter Zijlstra 已提交
8973 8974 8975 8976
	for_each_task_context_nr(ctxn) {
		ctx = task->perf_event_ctxp[ctxn];
		if (!ctx)
			continue;
8977

P
Peter Zijlstra 已提交
8978
		mutex_lock(&ctx->mutex);
8979
again:
P
Peter Zijlstra 已提交
8980 8981 8982
		list_for_each_entry_safe(event, tmp, &ctx->pinned_groups,
				group_entry)
			perf_free_event(event, ctx);
8983

P
Peter Zijlstra 已提交
8984 8985 8986
		list_for_each_entry_safe(event, tmp, &ctx->flexible_groups,
				group_entry)
			perf_free_event(event, ctx);
8987

P
Peter Zijlstra 已提交
8988 8989 8990
		if (!list_empty(&ctx->pinned_groups) ||
				!list_empty(&ctx->flexible_groups))
			goto again;
8991

P
Peter Zijlstra 已提交
8992
		mutex_unlock(&ctx->mutex);
8993

P
Peter Zijlstra 已提交
8994 8995
		put_ctx(ctx);
	}
8996 8997
}

8998 8999 9000 9001 9002 9003 9004 9005
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]);
}

9006
struct file *perf_event_get(unsigned int fd)
9007
{
9008
	struct file *file;
9009

9010 9011 9012
	file = fget_raw(fd);
	if (!file)
		return ERR_PTR(-EBADF);
9013

9014 9015 9016 9017
	if (file->f_op != &perf_fops) {
		fput(file);
		return ERR_PTR(-EBADF);
	}
9018

9019
	return file;
9020 9021 9022 9023 9024 9025 9026 9027 9028 9029
}

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
9030 9031 9032 9033 9034 9035 9036 9037 9038 9039 9040
/*
 * 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)
{
9041
	enum perf_event_active_state parent_state = parent_event->state;
P
Peter Zijlstra 已提交
9042
	struct perf_event *child_event;
9043
	unsigned long flags;
P
Peter Zijlstra 已提交
9044 9045 9046 9047 9048 9049 9050 9051 9052 9053 9054 9055

	/*
	 * 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,
9056
					   child,
P
Peter Zijlstra 已提交
9057
					   group_leader, parent_event,
9058
					   NULL, NULL, -1);
P
Peter Zijlstra 已提交
9059 9060
	if (IS_ERR(child_event))
		return child_event;
9061

9062 9063 9064 9065 9066 9067 9068
	/*
	 * 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);
9069 9070
	if (is_orphaned_event(parent_event) ||
	    !atomic_long_inc_not_zero(&parent_event->refcount)) {
9071
		mutex_unlock(&parent_event->child_mutex);
9072 9073 9074 9075
		free_event(child_event);
		return NULL;
	}

P
Peter Zijlstra 已提交
9076 9077 9078 9079 9080 9081 9082
	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.
	 */
9083
	if (parent_state >= PERF_EVENT_STATE_INACTIVE)
P
Peter Zijlstra 已提交
9084 9085 9086 9087 9088 9089 9090 9091 9092 9093 9094 9095 9096 9097 9098 9099
		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;
9100 9101
	child_event->overflow_handler_context
		= parent_event->overflow_handler_context;
P
Peter Zijlstra 已提交
9102

9103 9104 9105 9106
	/*
	 * Precalculate sample_data sizes
	 */
	perf_event__header_size(child_event);
9107
	perf_event__id_header_size(child_event);
9108

P
Peter Zijlstra 已提交
9109 9110 9111
	/*
	 * Link it up in the child's context:
	 */
9112
	raw_spin_lock_irqsave(&child_ctx->lock, flags);
P
Peter Zijlstra 已提交
9113
	add_event_to_ctx(child_event, child_ctx);
9114
	raw_spin_unlock_irqrestore(&child_ctx->lock, flags);
P
Peter Zijlstra 已提交
9115 9116 9117 9118 9119 9120 9121 9122 9123 9124 9125 9126 9127 9128 9129 9130 9131 9132 9133 9134 9135 9136 9137 9138 9139 9140 9141 9142 9143 9144 9145

	/*
	 * 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;
9146 9147 9148 9149 9150
}

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
9151
		   struct task_struct *child, int ctxn,
9152 9153 9154
		   int *inherited_all)
{
	int ret;
P
Peter Zijlstra 已提交
9155
	struct perf_event_context *child_ctx;
9156 9157 9158 9159

	if (!event->attr.inherit) {
		*inherited_all = 0;
		return 0;
9160 9161
	}

9162
	child_ctx = child->perf_event_ctxp[ctxn];
9163 9164 9165 9166 9167 9168 9169
	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.
		 */
9170

9171
		child_ctx = alloc_perf_context(parent_ctx->pmu, child);
9172 9173
		if (!child_ctx)
			return -ENOMEM;
9174

P
Peter Zijlstra 已提交
9175
		child->perf_event_ctxp[ctxn] = child_ctx;
9176 9177 9178 9179 9180 9181 9182 9183 9184
	}

	ret = inherit_group(event, parent, parent_ctx,
			    child, child_ctx);

	if (ret)
		*inherited_all = 0;

	return ret;
9185 9186
}

9187
/*
9188
 * Initialize the perf_event context in task_struct
9189
 */
9190
static int perf_event_init_context(struct task_struct *child, int ctxn)
9191
{
9192
	struct perf_event_context *child_ctx, *parent_ctx;
9193 9194
	struct perf_event_context *cloned_ctx;
	struct perf_event *event;
9195
	struct task_struct *parent = current;
9196
	int inherited_all = 1;
9197
	unsigned long flags;
9198
	int ret = 0;
9199

P
Peter Zijlstra 已提交
9200
	if (likely(!parent->perf_event_ctxp[ctxn]))
9201 9202
		return 0;

9203
	/*
9204 9205
	 * If the parent's context is a clone, pin it so it won't get
	 * swapped under us.
9206
	 */
P
Peter Zijlstra 已提交
9207
	parent_ctx = perf_pin_task_context(parent, ctxn);
9208 9209
	if (!parent_ctx)
		return 0;
9210

9211 9212 9213 9214 9215 9216 9217
	/*
	 * 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.
	 */

9218 9219 9220 9221
	/*
	 * Lock the parent list. No need to lock the child - not PID
	 * hashed yet and not running, so nobody can access it.
	 */
9222
	mutex_lock(&parent_ctx->mutex);
9223 9224 9225 9226 9227

	/*
	 * We dont have to disable NMIs - we are only looking at
	 * the list, not manipulating it:
	 */
9228
	list_for_each_entry(event, &parent_ctx->pinned_groups, group_entry) {
P
Peter Zijlstra 已提交
9229 9230
		ret = inherit_task_group(event, parent, parent_ctx,
					 child, ctxn, &inherited_all);
9231 9232 9233
		if (ret)
			break;
	}
9234

9235 9236 9237 9238 9239 9240 9241 9242 9243
	/*
	 * 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);

9244
	list_for_each_entry(event, &parent_ctx->flexible_groups, group_entry) {
P
Peter Zijlstra 已提交
9245 9246
		ret = inherit_task_group(event, parent, parent_ctx,
					 child, ctxn, &inherited_all);
9247
		if (ret)
9248
			break;
9249 9250
	}

9251 9252 9253
	raw_spin_lock_irqsave(&parent_ctx->lock, flags);
	parent_ctx->rotate_disable = 0;

P
Peter Zijlstra 已提交
9254
	child_ctx = child->perf_event_ctxp[ctxn];
9255

9256
	if (child_ctx && inherited_all) {
9257 9258 9259
		/*
		 * 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
9260 9261 9262
		 *
		 * Note that if the parent is a clone, the holding of
		 * parent_ctx->lock avoids it from being uncloned.
9263
		 */
P
Peter Zijlstra 已提交
9264
		cloned_ctx = parent_ctx->parent_ctx;
9265 9266
		if (cloned_ctx) {
			child_ctx->parent_ctx = cloned_ctx;
9267
			child_ctx->parent_gen = parent_ctx->parent_gen;
9268 9269 9270 9271 9272
		} else {
			child_ctx->parent_ctx = parent_ctx;
			child_ctx->parent_gen = parent_ctx->generation;
		}
		get_ctx(child_ctx->parent_ctx);
9273 9274
	}

P
Peter Zijlstra 已提交
9275
	raw_spin_unlock_irqrestore(&parent_ctx->lock, flags);
9276
	mutex_unlock(&parent_ctx->mutex);
9277

9278
	perf_unpin_context(parent_ctx);
9279
	put_ctx(parent_ctx);
9280

9281
	return ret;
9282 9283
}

P
Peter Zijlstra 已提交
9284 9285 9286 9287 9288 9289 9290
/*
 * Initialize the perf_event context in task_struct
 */
int perf_event_init_task(struct task_struct *child)
{
	int ctxn, ret;

9291 9292 9293 9294
	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
9295 9296
	for_each_task_context_nr(ctxn) {
		ret = perf_event_init_context(child, ctxn);
P
Peter Zijlstra 已提交
9297 9298
		if (ret) {
			perf_event_free_task(child);
P
Peter Zijlstra 已提交
9299
			return ret;
P
Peter Zijlstra 已提交
9300
		}
P
Peter Zijlstra 已提交
9301 9302 9303 9304 9305
	}

	return 0;
}

9306 9307
static void __init perf_event_init_all_cpus(void)
{
9308
	struct swevent_htable *swhash;
9309 9310 9311
	int cpu;

	for_each_possible_cpu(cpu) {
9312 9313
		swhash = &per_cpu(swevent_htable, cpu);
		mutex_init(&swhash->hlist_mutex);
9314
		INIT_LIST_HEAD(&per_cpu(active_ctx_list, cpu));
9315 9316 9317
	}
}

9318
static void perf_event_init_cpu(int cpu)
T
Thomas Gleixner 已提交
9319
{
P
Peter Zijlstra 已提交
9320
	struct swevent_htable *swhash = &per_cpu(swevent_htable, cpu);
T
Thomas Gleixner 已提交
9321

9322
	mutex_lock(&swhash->hlist_mutex);
9323
	if (swhash->hlist_refcount > 0 && !swevent_hlist_deref(swhash)) {
9324 9325
		struct swevent_hlist *hlist;

9326 9327 9328
		hlist = kzalloc_node(sizeof(*hlist), GFP_KERNEL, cpu_to_node(cpu));
		WARN_ON(!hlist);
		rcu_assign_pointer(swhash->swevent_hlist, hlist);
9329
	}
9330
	mutex_unlock(&swhash->hlist_mutex);
T
Thomas Gleixner 已提交
9331 9332
}

9333
#if defined CONFIG_HOTPLUG_CPU || defined CONFIG_KEXEC_CORE
P
Peter Zijlstra 已提交
9334
static void __perf_event_exit_context(void *__info)
T
Thomas Gleixner 已提交
9335
{
P
Peter Zijlstra 已提交
9336
	struct perf_event_context *ctx = __info;
9337 9338
	struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
	struct perf_event *event;
T
Thomas Gleixner 已提交
9339

9340 9341
	raw_spin_lock(&ctx->lock);
	list_for_each_entry(event, &ctx->event_list, event_entry)
9342
		__perf_remove_from_context(event, cpuctx, ctx, (void *)DETACH_GROUP);
9343
	raw_spin_unlock(&ctx->lock);
T
Thomas Gleixner 已提交
9344
}
P
Peter Zijlstra 已提交
9345 9346 9347 9348 9349 9350 9351 9352 9353

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) {
9354
		ctx = &per_cpu_ptr(pmu->pmu_cpu_context, cpu)->ctx;
P
Peter Zijlstra 已提交
9355 9356 9357 9358 9359 9360 9361 9362

		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);
}

9363
static void perf_event_exit_cpu(int cpu)
T
Thomas Gleixner 已提交
9364
{
P
Peter Zijlstra 已提交
9365
	perf_event_exit_cpu_context(cpu);
T
Thomas Gleixner 已提交
9366 9367
}
#else
9368
static inline void perf_event_exit_cpu(int cpu) { }
T
Thomas Gleixner 已提交
9369 9370
#endif

P
Peter Zijlstra 已提交
9371 9372 9373 9374 9375 9376 9377 9378 9379 9380 9381 9382 9383 9384 9385 9386 9387 9388 9389 9390
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,
};

9391
static int
T
Thomas Gleixner 已提交
9392 9393 9394 9395
perf_cpu_notify(struct notifier_block *self, unsigned long action, void *hcpu)
{
	unsigned int cpu = (long)hcpu;

9396
	switch (action & ~CPU_TASKS_FROZEN) {
T
Thomas Gleixner 已提交
9397 9398

	case CPU_UP_PREPARE:
9399
		perf_event_init_cpu(cpu);
T
Thomas Gleixner 已提交
9400 9401 9402
		break;

	case CPU_DOWN_PREPARE:
9403
		perf_event_exit_cpu(cpu);
T
Thomas Gleixner 已提交
9404 9405 9406 9407 9408 9409 9410 9411
		break;
	default:
		break;
	}

	return NOTIFY_OK;
}

9412
void __init perf_event_init(void)
T
Thomas Gleixner 已提交
9413
{
9414 9415
	int ret;

P
Peter Zijlstra 已提交
9416 9417
	idr_init(&pmu_idr);

9418
	perf_event_init_all_cpus();
9419
	init_srcu_struct(&pmus_srcu);
P
Peter Zijlstra 已提交
9420 9421 9422
	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);
9423 9424
	perf_tp_register();
	perf_cpu_notifier(perf_cpu_notify);
P
Peter Zijlstra 已提交
9425
	register_reboot_notifier(&perf_reboot_notifier);
9426 9427 9428

	ret = init_hw_breakpoint();
	WARN(ret, "hw_breakpoint initialization failed with: %d", ret);
9429

9430 9431 9432 9433 9434 9435
	/*
	 * 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
9436
}
P
Peter Zijlstra 已提交
9437

9438 9439 9440 9441 9442 9443 9444 9445 9446 9447 9448
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;
}
9449
EXPORT_SYMBOL_GPL(perf_event_sysfs_show);
9450

P
Peter Zijlstra 已提交
9451 9452 9453 9454 9455 9456 9457 9458 9459 9460 9461 9462 9463 9464 9465 9466 9467 9468 9469 9470 9471 9472 9473 9474 9475 9476 9477
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
9478 9479

#ifdef CONFIG_CGROUP_PERF
9480 9481
static struct cgroup_subsys_state *
perf_cgroup_css_alloc(struct cgroup_subsys_state *parent_css)
S
Stephane Eranian 已提交
9482 9483 9484
{
	struct perf_cgroup *jc;

9485
	jc = kzalloc(sizeof(*jc), GFP_KERNEL);
S
Stephane Eranian 已提交
9486 9487 9488 9489 9490 9491 9492 9493 9494 9495 9496 9497
	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;
}

9498
static void perf_cgroup_css_free(struct cgroup_subsys_state *css)
S
Stephane Eranian 已提交
9499
{
9500 9501
	struct perf_cgroup *jc = container_of(css, struct perf_cgroup, css);

S
Stephane Eranian 已提交
9502 9503 9504 9505 9506 9507 9508
	free_percpu(jc->info);
	kfree(jc);
}

static int __perf_cgroup_move(void *info)
{
	struct task_struct *task = info;
9509
	rcu_read_lock();
S
Stephane Eranian 已提交
9510
	perf_cgroup_switch(task, PERF_CGROUP_SWOUT | PERF_CGROUP_SWIN);
9511
	rcu_read_unlock();
S
Stephane Eranian 已提交
9512 9513 9514
	return 0;
}

9515
static void perf_cgroup_attach(struct cgroup_taskset *tset)
S
Stephane Eranian 已提交
9516
{
9517
	struct task_struct *task;
9518
	struct cgroup_subsys_state *css;
9519

9520
	cgroup_taskset_for_each(task, css, tset)
9521
		task_function_call(task, __perf_cgroup_move, task);
S
Stephane Eranian 已提交
9522 9523
}

9524
struct cgroup_subsys perf_event_cgrp_subsys = {
9525 9526
	.css_alloc	= perf_cgroup_css_alloc,
	.css_free	= perf_cgroup_css_free,
9527
	.attach		= perf_cgroup_attach,
S
Stephane Eranian 已提交
9528 9529
};
#endif /* CONFIG_CGROUP_PERF */