core.c 185.7 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
 *  Copyright (C) 2008-2011 Red Hat, Inc., Peter Zijlstra <pzijlstr@redhat.com>
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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/perf_event.h>
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#include <linux/ftrace_event.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/cgroup.h>
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#include "internal.h"

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#include <asm/irq_regs.h>

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struct remote_function_call {
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	struct task_struct	*p;
	int			(*func)(void *info);
	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) {
		tfc->ret = -EAGAIN;
		if (task_cpu(p) != smp_processor_id() || !task_curr(p))
			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
task_function_call(struct task_struct *p, int (*func) (void *info), void *info)
{
	struct remote_function_call data = {
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		.p	= p,
		.func	= func,
		.info	= info,
		.ret	= -ESRCH, /* No such (running) process */
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	};

	if (task_curr(p))
		smp_call_function_single(task_cpu(p), remote_function, &data, 1);

	return data.ret;
}

/**
 * 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
 */
static int cpu_function_call(int cpu, int (*func) (void *info), void *info)
{
	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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#define PERF_FLAG_ALL (PERF_FLAG_FD_NO_GROUP |\
		       PERF_FLAG_FD_OUTPUT  |\
		       PERF_FLAG_PID_CGROUP)

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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,
	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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struct static_key_deferred perf_sched_events __read_mostly;
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static DEFINE_PER_CPU(atomic_t, perf_cgroup_events);
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static DEFINE_PER_CPU(atomic_t, perf_branch_stack_events);
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static atomic_t nr_mmap_events __read_mostly;
static atomic_t nr_comm_events __read_mostly;
static atomic_t nr_task_events __read_mostly;
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static atomic_t nr_freq_events __read_mostly;
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static 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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void update_perf_cpu_limits(void)
{
	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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void perf_sample_event_took(u64 sample_len_ns)
{
	u64 avg_local_sample_len;
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	u64 local_samples_len;
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	u64 allowed_ns = ACCESS_ONCE(perf_sample_allowed_ns);
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	if (allowed_ns == 0)
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		return;

	/* decay the counter by 1 average sample */
	local_samples_len = __get_cpu_var(running_sample_length);
	local_samples_len -= local_samples_len/NR_ACCUMULATED_SAMPLES;
	local_samples_len += sample_len_ns;
	__get_cpu_var(running_sample_length) = local_samples_len;

	/*
	 * 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;

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

	update_perf_cpu_limits();
}

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

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static void perf_ctx_lock(struct perf_cpu_context *cpuctx,
			  struct perf_event_context *ctx)
{
	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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#ifdef CONFIG_CGROUP_PERF

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/*
 * perf_cgroup_info keeps track of time_enabled for a cgroup.
 * This is a per-cpu dynamically allocated data structure.
 */
struct perf_cgroup_info {
	u64				time;
	u64				timestamp;
};

struct perf_cgroup {
	struct cgroup_subsys_state	css;
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	struct perf_cgroup_info	__percpu *info;
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};

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/*
 * Must ensure cgroup is pinned (css_get) before calling
 * this function. In other words, we cannot call this function
 * if there is no cgroup event for the current CPU context.
 */
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static inline struct perf_cgroup *
perf_cgroup_from_task(struct task_struct *task)
{
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	return container_of(task_css(task, perf_subsys_id),
			    struct perf_cgroup, css);
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}

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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}

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static inline bool perf_tryget_cgroup(struct perf_event *event)
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{
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	return css_tryget(&event->cgrp->css);
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}

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

static inline void perf_detach_cgroup(struct perf_event *event)
{
	perf_put_cgroup(event);
	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);
	/*
	 * 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;

	cgrp = perf_cgroup_from_task(task);
	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
 */
void perf_cgroup_switch(struct task_struct *task, int mode)
{
	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.
	 */
	rcu_read_lock();

	list_for_each_entry_rcu(pmu, &pmus, entry) {
		cpuctx = this_cpu_ptr(pmu->pmu_cpu_context);
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		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) {
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			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) {
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				WARN_ON_ONCE(cpuctx->cgrp);
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				/*
				 * set cgrp before ctxsw in to allow
				 * event_filter_match() to not have to pass
				 * task around
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				 */
				cpuctx->cgrp = perf_cgroup_from_task(task);
				cpu_ctx_sched_in(cpuctx, EVENT_ALL, task);
			}
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			perf_pmu_enable(cpuctx->ctx.pmu);
			perf_ctx_unlock(cpuctx, cpuctx->task_ctx);
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		}
	}

	rcu_read_unlock();

	local_irq_restore(flags);
}

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static inline void perf_cgroup_sched_out(struct task_struct *task,
					 struct task_struct *next)
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{
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	struct perf_cgroup *cgrp1;
	struct perf_cgroup *cgrp2 = NULL;

	/*
	 * we come here when we know perf_cgroup_events > 0
	 */
	cgrp1 = perf_cgroup_from_task(task);

	/*
	 * next is NULL when called from perf_event_enable_on_exec()
	 * that will systematically cause a cgroup_switch()
	 */
	if (next)
		cgrp2 = perf_cgroup_from_task(next);

	/*
	 * 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);
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}

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static inline void perf_cgroup_sched_in(struct task_struct *prev,
					struct task_struct *task)
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{
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	struct perf_cgroup *cgrp1;
	struct perf_cgroup *cgrp2 = NULL;

	/*
	 * we come here when we know perf_cgroup_events > 0
	 */
	cgrp1 = perf_cgroup_from_task(task);

	/* prev can never be NULL */
	cgrp2 = perf_cgroup_from_task(prev);

	/*
	 * 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);
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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;
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	struct fd f = fdget(fd);
	int ret = 0;
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	if (!f.file)
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		return -EBADF;

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	rcu_read_lock();

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	css = css_from_dir(f.file->f_dentry, &perf_subsys);
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	if (IS_ERR(css)) {
		ret = PTR_ERR(css);
		goto out;
	}
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	cgrp = container_of(css, struct perf_cgroup, css);
	event->cgrp = cgrp;

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	/* must be done before we fput() the file */
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	if (!perf_tryget_cgroup(event)) {
		event->cgrp = NULL;
		ret = -ENOENT;
		goto out;
	}
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	/*
	 * 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;
	}
622
out:
623
	rcu_read_unlock();
624
	fdput(f);
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625 626 627 628 629 630 631 632 633 634 635 636 637 638 639 640 641 642 643 644 645 646 647 648 649 650 651 652 653 654 655 656 657 658 659 660 661 662 663 664 665 666 667 668 669 670 671 672 673 674 675 676 677 678 679 680 681 682 683 684 685 686 687 688 689 690 691 692 693 694 695 696 697
	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)
{
}

698 699
static inline void perf_cgroup_sched_out(struct task_struct *task,
					 struct task_struct *next)
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{
}

703 704
static inline void perf_cgroup_sched_in(struct task_struct *prev,
					struct task_struct *task)
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{
}

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

static inline void
716 717
perf_cgroup_set_timestamp(struct task_struct *task,
			  struct perf_event_context *ctx)
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718 719 720 721 722 723 724 725 726 727 728 729 730 731 732 733 734 735 736 737 738 739 740 741 742 743 744 745 746 747
{
}

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

748 749 750 751 752 753 754 755 756 757 758 759 760 761 762 763 764 765 766 767 768 769 770 771 772 773 774 775 776 777 778 779 780 781 782 783 784 785 786 787 788 789 790 791 792 793 794 795 796 797 798 799 800 801 802 803 804 805 806 807 808 809 810
/*
 * 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
 */
static enum hrtimer_restart perf_cpu_hrtimer_handler(struct hrtimer *hr)
{
	struct perf_cpu_context *cpuctx;
	enum hrtimer_restart ret = HRTIMER_NORESTART;
	int rotations = 0;

	WARN_ON(!irqs_disabled());

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

	rotations = perf_rotate_context(cpuctx);

	/*
	 * arm timer if needed
	 */
	if (rotations) {
		hrtimer_forward_now(hr, cpuctx->hrtimer_interval);
		ret = HRTIMER_RESTART;
	}

	return ret;
}

/* CPU is going down */
void perf_cpu_hrtimer_cancel(int cpu)
{
	struct perf_cpu_context *cpuctx;
	struct pmu *pmu;
	unsigned long flags;

	if (WARN_ON(cpu != smp_processor_id()))
		return;

	local_irq_save(flags);

	rcu_read_lock();

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

		if (pmu->task_ctx_nr == perf_sw_context)
			continue;

		hrtimer_cancel(&cpuctx->hrtimer);
	}

	rcu_read_unlock();

	local_irq_restore(flags);
}

static void __perf_cpu_hrtimer_init(struct perf_cpu_context *cpuctx, int cpu)
{
	struct hrtimer *hr = &cpuctx->hrtimer;
	struct pmu *pmu = cpuctx->ctx.pmu;
811
	int timer;
812 813 814 815 816

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

817 818 819 820 821 822 823 824 825
	/*
	 * check default is sane, if not set then force to
	 * default interval (1/tick)
	 */
	timer = pmu->hrtimer_interval_ms;
	if (timer < 1)
		timer = pmu->hrtimer_interval_ms = PERF_CPU_HRTIMER;

	cpuctx->hrtimer_interval = ns_to_ktime(NSEC_PER_MSEC * timer);
826 827 828 829 830 831 832 833 834 835 836 837 838 839 840 841 842 843 844 845 846 847

	hrtimer_init(hr, CLOCK_MONOTONIC, HRTIMER_MODE_REL_PINNED);
	hr->function = perf_cpu_hrtimer_handler;
}

static void perf_cpu_hrtimer_restart(struct perf_cpu_context *cpuctx)
{
	struct hrtimer *hr = &cpuctx->hrtimer;
	struct pmu *pmu = cpuctx->ctx.pmu;

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

	if (hrtimer_active(hr))
		return;

	if (!hrtimer_callback_running(hr))
		__hrtimer_start_range_ns(hr, cpuctx->hrtimer_interval,
					 0, HRTIMER_MODE_REL_PINNED, 0);
}

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Peter Zijlstra 已提交
848
void perf_pmu_disable(struct pmu *pmu)
849
{
P
Peter Zijlstra 已提交
850 851 852
	int *count = this_cpu_ptr(pmu->pmu_disable_count);
	if (!(*count)++)
		pmu->pmu_disable(pmu);
853 854
}

P
Peter Zijlstra 已提交
855
void perf_pmu_enable(struct pmu *pmu)
856
{
P
Peter Zijlstra 已提交
857 858 859
	int *count = this_cpu_ptr(pmu->pmu_disable_count);
	if (!--(*count))
		pmu->pmu_enable(pmu);
860 861
}

862 863 864 865 866 867 868
static DEFINE_PER_CPU(struct list_head, rotation_list);

/*
 * perf_pmu_rotate_start() and perf_rotate_context() are fully serialized
 * because they're strictly cpu affine and rotate_start is called with IRQs
 * disabled, while rotate_context is called from IRQ context.
 */
P
Peter Zijlstra 已提交
869
static void perf_pmu_rotate_start(struct pmu *pmu)
870
{
P
Peter Zijlstra 已提交
871
	struct perf_cpu_context *cpuctx = this_cpu_ptr(pmu->pmu_cpu_context);
872
	struct list_head *head = &__get_cpu_var(rotation_list);
873

874
	WARN_ON(!irqs_disabled());
875

876
	if (list_empty(&cpuctx->rotation_list))
877
		list_add(&cpuctx->rotation_list, head);
878 879
}

880
static void get_ctx(struct perf_event_context *ctx)
881
{
882
	WARN_ON(!atomic_inc_not_zero(&ctx->refcount));
883 884
}

885
static void put_ctx(struct perf_event_context *ctx)
886
{
887 888 889
	if (atomic_dec_and_test(&ctx->refcount)) {
		if (ctx->parent_ctx)
			put_ctx(ctx->parent_ctx);
890 891
		if (ctx->task)
			put_task_struct(ctx->task);
892
		kfree_rcu(ctx, rcu_head);
893
	}
894 895
}

896
static void unclone_ctx(struct perf_event_context *ctx)
897 898 899 900 901
{
	if (ctx->parent_ctx) {
		put_ctx(ctx->parent_ctx);
		ctx->parent_ctx = NULL;
	}
902
	ctx->generation++;
903 904
}

905 906 907 908 909 910 911 912 913 914 915 916 917 918 919 920 921 922 923 924 925 926
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);
}

927
/*
928
 * If we inherit events we want to return the parent event id
929 930
 * to userspace.
 */
931
static u64 primary_event_id(struct perf_event *event)
932
{
933
	u64 id = event->id;
934

935 936
	if (event->parent)
		id = event->parent->id;
937 938 939 940

	return id;
}

941
/*
942
 * Get the perf_event_context for a task and lock it.
943 944 945
 * This has to cope with with the fact that until it is locked,
 * the context could get moved to another task.
 */
946
static struct perf_event_context *
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Peter Zijlstra 已提交
947
perf_lock_task_context(struct task_struct *task, int ctxn, unsigned long *flags)
948
{
949
	struct perf_event_context *ctx;
950

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951
retry:
952 953 954 955 956 957 958 959 960 961 962
	/*
	 * One of the few rules of preemptible RCU is that one cannot do
	 * rcu_read_unlock() while holding a scheduler (or nested) lock when
	 * part of the read side critical section was preemptible -- see
	 * rcu_read_unlock_special().
	 *
	 * Since ctx->lock nests under rq->lock we must ensure the entire read
	 * side critical section is non-preemptible.
	 */
	preempt_disable();
	rcu_read_lock();
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963
	ctx = rcu_dereference(task->perf_event_ctxp[ctxn]);
964 965 966 967
	if (ctx) {
		/*
		 * If this context is a clone of another, it might
		 * get swapped for another underneath us by
968
		 * perf_event_task_sched_out, though the
969 970 971 972 973 974
		 * 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.
		 */
975
		raw_spin_lock_irqsave(&ctx->lock, *flags);
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Peter Zijlstra 已提交
976
		if (ctx != rcu_dereference(task->perf_event_ctxp[ctxn])) {
977
			raw_spin_unlock_irqrestore(&ctx->lock, *flags);
978 979
			rcu_read_unlock();
			preempt_enable();
980 981
			goto retry;
		}
982 983

		if (!atomic_inc_not_zero(&ctx->refcount)) {
984
			raw_spin_unlock_irqrestore(&ctx->lock, *flags);
985 986
			ctx = NULL;
		}
987 988
	}
	rcu_read_unlock();
989
	preempt_enable();
990 991 992 993 994 995 996 997
	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.
 */
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static struct perf_event_context *
perf_pin_task_context(struct task_struct *task, int ctxn)
1000
{
1001
	struct perf_event_context *ctx;
1002 1003
	unsigned long flags;

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	ctx = perf_lock_task_context(task, ctxn, &flags);
1005 1006
	if (ctx) {
		++ctx->pin_count;
1007
		raw_spin_unlock_irqrestore(&ctx->lock, flags);
1008 1009 1010 1011
	}
	return ctx;
}

1012
static void perf_unpin_context(struct perf_event_context *ctx)
1013 1014 1015
{
	unsigned long flags;

1016
	raw_spin_lock_irqsave(&ctx->lock, flags);
1017
	--ctx->pin_count;
1018
	raw_spin_unlock_irqrestore(&ctx->lock, flags);
1019 1020
}

1021 1022 1023 1024 1025 1026 1027 1028 1029 1030 1031
/*
 * 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;
}

1032 1033 1034
static u64 perf_event_time(struct perf_event *event)
{
	struct perf_event_context *ctx = event->ctx;
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1035 1036 1037 1038

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

1039 1040 1041
	return ctx ? ctx->time : 0;
}

1042 1043
/*
 * Update the total_time_enabled and total_time_running fields for a event.
1044
 * The caller of this function needs to hold the ctx->lock.
1045 1046 1047 1048 1049 1050 1051 1052 1053
 */
static void update_event_times(struct perf_event *event)
{
	struct perf_event_context *ctx = event->ctx;
	u64 run_end;

	if (event->state < PERF_EVENT_STATE_INACTIVE ||
	    event->group_leader->state < PERF_EVENT_STATE_INACTIVE)
		return;
S
Stephane Eranian 已提交
1054 1055 1056 1057 1058 1059 1060 1061 1062 1063 1064
	/*
	 * 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))
1065
		run_end = perf_cgroup_event_time(event);
S
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1066 1067
	else if (ctx->is_active)
		run_end = ctx->time;
1068 1069 1070 1071
	else
		run_end = event->tstamp_stopped;

	event->total_time_enabled = run_end - event->tstamp_enabled;
1072 1073 1074 1075

	if (event->state == PERF_EVENT_STATE_INACTIVE)
		run_end = event->tstamp_stopped;
	else
1076
		run_end = perf_event_time(event);
1077 1078

	event->total_time_running = run_end - event->tstamp_running;
S
Stephane Eranian 已提交
1079

1080 1081
}

1082 1083 1084 1085 1086 1087 1088 1089 1090 1091 1092 1093
/*
 * 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);
}

1094 1095 1096 1097 1098 1099 1100 1101 1102
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;
}

1103
/*
1104
 * Add a event from the lists for its context.
1105 1106
 * Must be called with ctx->mutex and ctx->lock held.
 */
1107
static void
1108
list_add_event(struct perf_event *event, struct perf_event_context *ctx)
1109
{
1110 1111
	WARN_ON_ONCE(event->attach_state & PERF_ATTACH_CONTEXT);
	event->attach_state |= PERF_ATTACH_CONTEXT;
1112 1113

	/*
1114 1115 1116
	 * 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.
1117
	 */
1118
	if (event->group_leader == event) {
1119 1120
		struct list_head *list;

1121 1122 1123
		if (is_software_event(event))
			event->group_flags |= PERF_GROUP_SOFTWARE;

1124 1125
		list = ctx_group_list(event, ctx);
		list_add_tail(&event->group_entry, list);
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Peter Zijlstra 已提交
1126
	}
P
Peter Zijlstra 已提交
1127

1128
	if (is_cgroup_event(event))
S
Stephane Eranian 已提交
1129 1130
		ctx->nr_cgroups++;

1131 1132 1133
	if (has_branch_stack(event))
		ctx->nr_branch_stack++;

1134
	list_add_rcu(&event->event_entry, &ctx->event_list);
1135
	if (!ctx->nr_events)
P
Peter Zijlstra 已提交
1136
		perf_pmu_rotate_start(ctx->pmu);
1137 1138
	ctx->nr_events++;
	if (event->attr.inherit_stat)
1139
		ctx->nr_stat++;
1140 1141

	ctx->generation++;
1142 1143
}

J
Jiri Olsa 已提交
1144 1145 1146 1147 1148 1149 1150 1151 1152
/*
 * 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;
}

1153 1154 1155 1156 1157 1158 1159 1160 1161 1162 1163 1164 1165 1166 1167 1168 1169 1170 1171 1172 1173 1174 1175 1176 1177 1178 1179 1180 1181 1182 1183 1184 1185 1186 1187 1188 1189 1190 1191
/*
 * Called at perf_event creation and when events are attached/detached from a
 * group.
 */
static void perf_event__read_size(struct perf_event *event)
{
	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) {
		nr += event->group_leader->nr_siblings;
		size += sizeof(u64);
	}

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

static void perf_event__header_size(struct perf_event *event)
{
	struct perf_sample_data *data;
	u64 sample_type = event->attr.sample_type;
	u16 size = 0;

	perf_event__read_size(event);

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

1192 1193 1194 1195 1196 1197
	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
1198 1199 1200
	if (sample_type & PERF_SAMPLE_WEIGHT)
		size += sizeof(data->weight);

1201 1202 1203
	if (sample_type & PERF_SAMPLE_READ)
		size += event->read_size;

1204 1205 1206
	if (sample_type & PERF_SAMPLE_DATA_SRC)
		size += sizeof(data->data_src.val);

A
Andi Kleen 已提交
1207 1208 1209
	if (sample_type & PERF_SAMPLE_TRANSACTION)
		size += sizeof(data->txn);

1210 1211 1212 1213 1214 1215 1216 1217 1218
	event->header_size = size;
}

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;

1219 1220 1221 1222 1223 1224
	if (sample_type & PERF_SAMPLE_TID)
		size += sizeof(data->tid_entry);

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

1225 1226 1227
	if (sample_type & PERF_SAMPLE_IDENTIFIER)
		size += sizeof(data->id);

1228 1229 1230 1231 1232 1233 1234 1235 1236
	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);

1237
	event->id_header_size = size;
1238 1239
}

1240 1241
static void perf_group_attach(struct perf_event *event)
{
1242
	struct perf_event *group_leader = event->group_leader, *pos;
1243

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Peter Zijlstra 已提交
1244 1245 1246 1247 1248 1249
	/*
	 * We can have double attach due to group movement in perf_event_open.
	 */
	if (event->attach_state & PERF_ATTACH_GROUP)
		return;

1250 1251 1252 1253 1254 1255 1256 1257 1258 1259 1260
	event->attach_state |= PERF_ATTACH_GROUP;

	if (group_leader == event)
		return;

	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++;
1261 1262 1263 1264 1265

	perf_event__header_size(group_leader);

	list_for_each_entry(pos, &group_leader->sibling_list, group_entry)
		perf_event__header_size(pos);
1266 1267
}

1268
/*
1269
 * Remove a event from the lists for its context.
1270
 * Must be called with ctx->mutex and ctx->lock held.
1271
 */
1272
static void
1273
list_del_event(struct perf_event *event, struct perf_event_context *ctx)
1274
{
1275
	struct perf_cpu_context *cpuctx;
1276 1277 1278 1279
	/*
	 * We can have double detach due to exit/hot-unplug + close.
	 */
	if (!(event->attach_state & PERF_ATTACH_CONTEXT))
1280
		return;
1281 1282 1283

	event->attach_state &= ~PERF_ATTACH_CONTEXT;

1284
	if (is_cgroup_event(event)) {
S
Stephane Eranian 已提交
1285
		ctx->nr_cgroups--;
1286 1287 1288 1289 1290 1291 1292 1293 1294
		cpuctx = __get_cpu_context(ctx);
		/*
		 * if there are no more cgroup events
		 * then cler cgrp to avoid stale pointer
		 * in update_cgrp_time_from_cpuctx()
		 */
		if (!ctx->nr_cgroups)
			cpuctx->cgrp = NULL;
	}
S
Stephane Eranian 已提交
1295

1296 1297 1298
	if (has_branch_stack(event))
		ctx->nr_branch_stack--;

1299 1300
	ctx->nr_events--;
	if (event->attr.inherit_stat)
1301
		ctx->nr_stat--;
1302

1303
	list_del_rcu(&event->event_entry);
1304

1305 1306
	if (event->group_leader == event)
		list_del_init(&event->group_entry);
P
Peter Zijlstra 已提交
1307

1308
	update_group_times(event);
1309 1310 1311 1312 1313 1314 1315 1316 1317 1318

	/*
	 * 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;
1319 1320

	ctx->generation++;
1321 1322
}

1323
static void perf_group_detach(struct perf_event *event)
1324 1325
{
	struct perf_event *sibling, *tmp;
1326 1327 1328 1329 1330 1331 1332 1333 1334 1335 1336 1337 1338 1339 1340 1341
	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--;
1342
		goto out;
1343 1344 1345 1346
	}

	if (!list_empty(&event->group_entry))
		list = &event->group_entry;
1347

1348
	/*
1349 1350
	 * If this was a group event with sibling events then
	 * upgrade the siblings to singleton events by adding them
1351
	 * to whatever list we are on.
1352
	 */
1353
	list_for_each_entry_safe(sibling, tmp, &event->sibling_list, group_entry) {
1354 1355
		if (list)
			list_move_tail(&sibling->group_entry, list);
1356
		sibling->group_leader = sibling;
1357 1358 1359

		/* Inherit group flags from the previous leader */
		sibling->group_flags = event->group_flags;
1360
	}
1361 1362 1363 1364 1365 1366

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);
1367 1368
}

1369 1370 1371
static inline int
event_filter_match(struct perf_event *event)
{
S
Stephane Eranian 已提交
1372 1373
	return (event->cpu == -1 || event->cpu == smp_processor_id())
	    && perf_cgroup_match(event);
1374 1375
}

1376 1377
static void
event_sched_out(struct perf_event *event,
1378
		  struct perf_cpu_context *cpuctx,
1379
		  struct perf_event_context *ctx)
1380
{
1381
	u64 tstamp = perf_event_time(event);
1382 1383 1384 1385 1386 1387 1388 1389 1390
	u64 delta;
	/*
	 * 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
1391
		delta = tstamp - event->tstamp_stopped;
1392
		event->tstamp_running += delta;
1393
		event->tstamp_stopped = tstamp;
1394 1395
	}

1396
	if (event->state != PERF_EVENT_STATE_ACTIVE)
1397
		return;
1398

1399 1400 1401 1402
	event->state = PERF_EVENT_STATE_INACTIVE;
	if (event->pending_disable) {
		event->pending_disable = 0;
		event->state = PERF_EVENT_STATE_OFF;
1403
	}
1404
	event->tstamp_stopped = tstamp;
P
Peter Zijlstra 已提交
1405
	event->pmu->del(event, 0);
1406
	event->oncpu = -1;
1407

1408
	if (!is_software_event(event))
1409 1410
		cpuctx->active_oncpu--;
	ctx->nr_active--;
1411 1412
	if (event->attr.freq && event->attr.sample_freq)
		ctx->nr_freq--;
1413
	if (event->attr.exclusive || !cpuctx->active_oncpu)
1414 1415 1416
		cpuctx->exclusive = 0;
}

1417
static void
1418
group_sched_out(struct perf_event *group_event,
1419
		struct perf_cpu_context *cpuctx,
1420
		struct perf_event_context *ctx)
1421
{
1422
	struct perf_event *event;
1423
	int state = group_event->state;
1424

1425
	event_sched_out(group_event, cpuctx, ctx);
1426 1427 1428 1429

	/*
	 * Schedule out siblings (if any):
	 */
1430 1431
	list_for_each_entry(event, &group_event->sibling_list, group_entry)
		event_sched_out(event, cpuctx, ctx);
1432

1433
	if (state == PERF_EVENT_STATE_ACTIVE && group_event->attr.exclusive)
1434 1435 1436
		cpuctx->exclusive = 0;
}

T
Thomas Gleixner 已提交
1437
/*
1438
 * Cross CPU call to remove a performance event
T
Thomas Gleixner 已提交
1439
 *
1440
 * We disable the event on the hardware level first. After that we
T
Thomas Gleixner 已提交
1441 1442
 * remove it from the context list.
 */
1443
static int __perf_remove_from_context(void *info)
T
Thomas Gleixner 已提交
1444
{
1445 1446
	struct perf_event *event = info;
	struct perf_event_context *ctx = event->ctx;
P
Peter Zijlstra 已提交
1447
	struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
T
Thomas Gleixner 已提交
1448

1449
	raw_spin_lock(&ctx->lock);
1450 1451
	event_sched_out(event, cpuctx, ctx);
	list_del_event(event, ctx);
1452 1453 1454 1455
	if (!ctx->nr_events && cpuctx->task_ctx == ctx) {
		ctx->is_active = 0;
		cpuctx->task_ctx = NULL;
	}
1456
	raw_spin_unlock(&ctx->lock);
1457 1458

	return 0;
T
Thomas Gleixner 已提交
1459 1460 1461 1462
}


/*
1463
 * Remove the event from a task's (or a CPU's) list of events.
T
Thomas Gleixner 已提交
1464
 *
1465
 * CPU events are removed with a smp call. For task events we only
T
Thomas Gleixner 已提交
1466
 * call when the task is on a CPU.
1467
 *
1468 1469
 * If event->ctx is a cloned context, callers must make sure that
 * every task struct that event->ctx->task could possibly point to
1470 1471
 * 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.
1472
 * When called from perf_event_exit_task, it's OK because the
1473
 * context has been detached from its task.
T
Thomas Gleixner 已提交
1474
 */
1475
static void perf_remove_from_context(struct perf_event *event)
T
Thomas Gleixner 已提交
1476
{
1477
	struct perf_event_context *ctx = event->ctx;
T
Thomas Gleixner 已提交
1478 1479
	struct task_struct *task = ctx->task;

1480 1481
	lockdep_assert_held(&ctx->mutex);

T
Thomas Gleixner 已提交
1482 1483
	if (!task) {
		/*
1484
		 * Per cpu events are removed via an smp call and
1485
		 * the removal is always successful.
T
Thomas Gleixner 已提交
1486
		 */
1487
		cpu_function_call(event->cpu, __perf_remove_from_context, event);
T
Thomas Gleixner 已提交
1488 1489 1490 1491
		return;
	}

retry:
1492 1493
	if (!task_function_call(task, __perf_remove_from_context, event))
		return;
T
Thomas Gleixner 已提交
1494

1495
	raw_spin_lock_irq(&ctx->lock);
T
Thomas Gleixner 已提交
1496
	/*
1497 1498
	 * If we failed to find a running task, but find the context active now
	 * that we've acquired the ctx->lock, retry.
T
Thomas Gleixner 已提交
1499
	 */
1500
	if (ctx->is_active) {
1501
		raw_spin_unlock_irq(&ctx->lock);
T
Thomas Gleixner 已提交
1502 1503 1504 1505
		goto retry;
	}

	/*
1506 1507
	 * Since the task isn't running, its safe to remove the event, us
	 * holding the ctx->lock ensures the task won't get scheduled in.
T
Thomas Gleixner 已提交
1508
	 */
1509
	list_del_event(event, ctx);
1510
	raw_spin_unlock_irq(&ctx->lock);
T
Thomas Gleixner 已提交
1511 1512
}

1513
/*
1514
 * Cross CPU call to disable a performance event
1515
 */
1516
int __perf_event_disable(void *info)
1517
{
1518 1519
	struct perf_event *event = info;
	struct perf_event_context *ctx = event->ctx;
P
Peter Zijlstra 已提交
1520
	struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
1521 1522

	/*
1523 1524
	 * If this is a per-task event, need to check whether this
	 * event's task is the current task on this cpu.
1525 1526 1527
	 *
	 * Can trigger due to concurrent perf_event_context_sched_out()
	 * flipping contexts around.
1528
	 */
1529
	if (ctx->task && cpuctx->task_ctx != ctx)
1530
		return -EINVAL;
1531

1532
	raw_spin_lock(&ctx->lock);
1533 1534

	/*
1535
	 * If the event is on, turn it off.
1536 1537
	 * If it is in error state, leave it in error state.
	 */
1538
	if (event->state >= PERF_EVENT_STATE_INACTIVE) {
1539
		update_context_time(ctx);
S
Stephane Eranian 已提交
1540
		update_cgrp_time_from_event(event);
1541 1542 1543
		update_group_times(event);
		if (event == event->group_leader)
			group_sched_out(event, cpuctx, ctx);
1544
		else
1545 1546
			event_sched_out(event, cpuctx, ctx);
		event->state = PERF_EVENT_STATE_OFF;
1547 1548
	}

1549
	raw_spin_unlock(&ctx->lock);
1550 1551

	return 0;
1552 1553 1554
}

/*
1555
 * Disable a event.
1556
 *
1557 1558
 * If event->ctx is a cloned context, callers must make sure that
 * every task struct that event->ctx->task could possibly point to
1559
 * remains valid.  This condition is satisifed when called through
1560 1561 1562 1563
 * perf_event_for_each_child or perf_event_for_each because they
 * hold the top-level event's child_mutex, so any descendant that
 * goes to exit will block in sync_child_event.
 * When called from perf_pending_event it's OK because event->ctx
1564
 * is the current context on this CPU and preemption is disabled,
1565
 * hence we can't get into perf_event_task_sched_out for this context.
1566
 */
1567
void perf_event_disable(struct perf_event *event)
1568
{
1569
	struct perf_event_context *ctx = event->ctx;
1570 1571 1572 1573
	struct task_struct *task = ctx->task;

	if (!task) {
		/*
1574
		 * Disable the event on the cpu that it's on
1575
		 */
1576
		cpu_function_call(event->cpu, __perf_event_disable, event);
1577 1578 1579
		return;
	}

P
Peter Zijlstra 已提交
1580
retry:
1581 1582
	if (!task_function_call(task, __perf_event_disable, event))
		return;
1583

1584
	raw_spin_lock_irq(&ctx->lock);
1585
	/*
1586
	 * If the event is still active, we need to retry the cross-call.
1587
	 */
1588
	if (event->state == PERF_EVENT_STATE_ACTIVE) {
1589
		raw_spin_unlock_irq(&ctx->lock);
1590 1591 1592 1593 1594
		/*
		 * Reload the task pointer, it might have been changed by
		 * a concurrent perf_event_context_sched_out().
		 */
		task = ctx->task;
1595 1596 1597 1598 1599 1600 1601
		goto retry;
	}

	/*
	 * Since we have the lock this context can't be scheduled
	 * in, so we can change the state safely.
	 */
1602 1603 1604
	if (event->state == PERF_EVENT_STATE_INACTIVE) {
		update_group_times(event);
		event->state = PERF_EVENT_STATE_OFF;
1605
	}
1606
	raw_spin_unlock_irq(&ctx->lock);
1607
}
1608
EXPORT_SYMBOL_GPL(perf_event_disable);
1609

S
Stephane Eranian 已提交
1610 1611 1612 1613 1614 1615 1616 1617 1618 1619 1620 1621 1622 1623 1624 1625 1626 1627 1628 1629 1630 1631 1632 1633 1634 1635 1636 1637 1638 1639 1640 1641 1642 1643 1644
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
1645 1646 1647 1648
#define MAX_INTERRUPTS (~0ULL)

static void perf_log_throttle(struct perf_event *event, int enable);

1649
static int
1650
event_sched_in(struct perf_event *event,
1651
		 struct perf_cpu_context *cpuctx,
1652
		 struct perf_event_context *ctx)
1653
{
1654 1655
	u64 tstamp = perf_event_time(event);

1656
	if (event->state <= PERF_EVENT_STATE_OFF)
1657 1658
		return 0;

1659
	event->state = PERF_EVENT_STATE_ACTIVE;
1660
	event->oncpu = smp_processor_id();
P
Peter Zijlstra 已提交
1661 1662 1663 1664 1665 1666 1667 1668 1669 1670 1671

	/*
	 * 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;
	}

1672 1673 1674 1675 1676
	/*
	 * The new state must be visible before we turn it on in the hardware:
	 */
	smp_wmb();

P
Peter Zijlstra 已提交
1677
	if (event->pmu->add(event, PERF_EF_START)) {
1678 1679
		event->state = PERF_EVENT_STATE_INACTIVE;
		event->oncpu = -1;
1680 1681 1682
		return -EAGAIN;
	}

1683
	event->tstamp_running += tstamp - event->tstamp_stopped;
1684

S
Stephane Eranian 已提交
1685
	perf_set_shadow_time(event, ctx, tstamp);
1686

1687
	if (!is_software_event(event))
1688
		cpuctx->active_oncpu++;
1689
	ctx->nr_active++;
1690 1691
	if (event->attr.freq && event->attr.sample_freq)
		ctx->nr_freq++;
1692

1693
	if (event->attr.exclusive)
1694 1695
		cpuctx->exclusive = 1;

1696 1697 1698
	return 0;
}

1699
static int
1700
group_sched_in(struct perf_event *group_event,
1701
	       struct perf_cpu_context *cpuctx,
1702
	       struct perf_event_context *ctx)
1703
{
1704
	struct perf_event *event, *partial_group = NULL;
P
Peter Zijlstra 已提交
1705
	struct pmu *pmu = group_event->pmu;
1706 1707
	u64 now = ctx->time;
	bool simulate = false;
1708

1709
	if (group_event->state == PERF_EVENT_STATE_OFF)
1710 1711
		return 0;

P
Peter Zijlstra 已提交
1712
	pmu->start_txn(pmu);
1713

1714
	if (event_sched_in(group_event, cpuctx, ctx)) {
P
Peter Zijlstra 已提交
1715
		pmu->cancel_txn(pmu);
1716
		perf_cpu_hrtimer_restart(cpuctx);
1717
		return -EAGAIN;
1718
	}
1719 1720 1721 1722

	/*
	 * Schedule in siblings as one group (if any):
	 */
1723
	list_for_each_entry(event, &group_event->sibling_list, group_entry) {
1724
		if (event_sched_in(event, cpuctx, ctx)) {
1725
			partial_group = event;
1726 1727 1728 1729
			goto group_error;
		}
	}

1730
	if (!pmu->commit_txn(pmu))
1731
		return 0;
1732

1733 1734 1735 1736
group_error:
	/*
	 * Groups can be scheduled in as one unit only, so undo any
	 * partial group before returning:
1737 1738 1739 1740 1741 1742 1743 1744 1745 1746
	 * 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.
1747
	 */
1748 1749
	list_for_each_entry(event, &group_event->sibling_list, group_entry) {
		if (event == partial_group)
1750 1751 1752 1753 1754 1755 1756 1757
			simulate = true;

		if (simulate) {
			event->tstamp_running += now - event->tstamp_stopped;
			event->tstamp_stopped = now;
		} else {
			event_sched_out(event, cpuctx, ctx);
		}
1758
	}
1759
	event_sched_out(group_event, cpuctx, ctx);
1760

P
Peter Zijlstra 已提交
1761
	pmu->cancel_txn(pmu);
1762

1763 1764
	perf_cpu_hrtimer_restart(cpuctx);

1765 1766 1767
	return -EAGAIN;
}

1768
/*
1769
 * Work out whether we can put this event group on the CPU now.
1770
 */
1771
static int group_can_go_on(struct perf_event *event,
1772 1773 1774 1775
			   struct perf_cpu_context *cpuctx,
			   int can_add_hw)
{
	/*
1776
	 * Groups consisting entirely of software events can always go on.
1777
	 */
1778
	if (event->group_flags & PERF_GROUP_SOFTWARE)
1779 1780 1781
		return 1;
	/*
	 * If an exclusive group is already on, no other hardware
1782
	 * events can go on.
1783 1784 1785 1786 1787
	 */
	if (cpuctx->exclusive)
		return 0;
	/*
	 * If this group is exclusive and there are already
1788
	 * events on the CPU, it can't go on.
1789
	 */
1790
	if (event->attr.exclusive && cpuctx->active_oncpu)
1791 1792 1793 1794 1795 1796 1797 1798
		return 0;
	/*
	 * Otherwise, try to add it if all previous groups were able
	 * to go on.
	 */
	return can_add_hw;
}

1799 1800
static void add_event_to_ctx(struct perf_event *event,
			       struct perf_event_context *ctx)
1801
{
1802 1803
	u64 tstamp = perf_event_time(event);

1804
	list_add_event(event, ctx);
1805
	perf_group_attach(event);
1806 1807 1808
	event->tstamp_enabled = tstamp;
	event->tstamp_running = tstamp;
	event->tstamp_stopped = tstamp;
1809 1810
}

1811 1812 1813 1814 1815 1816
static void task_ctx_sched_out(struct perf_event_context *ctx);
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);
1817

1818 1819 1820 1821 1822 1823 1824 1825 1826 1827 1828 1829
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);
}

T
Thomas Gleixner 已提交
1830
/*
1831
 * Cross CPU call to install and enable a performance event
1832 1833
 *
 * Must be called with ctx->mutex held
T
Thomas Gleixner 已提交
1834
 */
1835
static int  __perf_install_in_context(void *info)
T
Thomas Gleixner 已提交
1836
{
1837 1838
	struct perf_event *event = info;
	struct perf_event_context *ctx = event->ctx;
P
Peter Zijlstra 已提交
1839
	struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
1840 1841 1842
	struct perf_event_context *task_ctx = cpuctx->task_ctx;
	struct task_struct *task = current;

1843
	perf_ctx_lock(cpuctx, task_ctx);
1844
	perf_pmu_disable(cpuctx->ctx.pmu);
T
Thomas Gleixner 已提交
1845 1846

	/*
1847
	 * If there was an active task_ctx schedule it out.
T
Thomas Gleixner 已提交
1848
	 */
1849
	if (task_ctx)
1850
		task_ctx_sched_out(task_ctx);
1851 1852 1853 1854 1855 1856 1857 1858 1859 1860 1861 1862 1863 1864

	/*
	 * If the context we're installing events in is not the
	 * active task_ctx, flip them.
	 */
	if (ctx->task && task_ctx != ctx) {
		if (task_ctx)
			raw_spin_unlock(&task_ctx->lock);
		raw_spin_lock(&ctx->lock);
		task_ctx = ctx;
	}

	if (task_ctx) {
		cpuctx->task_ctx = task_ctx;
1865 1866
		task = task_ctx->task;
	}
1867

1868
	cpu_ctx_sched_out(cpuctx, EVENT_ALL);
T
Thomas Gleixner 已提交
1869

1870
	update_context_time(ctx);
S
Stephane Eranian 已提交
1871 1872 1873 1874 1875 1876
	/*
	 * update cgrp time only if current cgrp
	 * matches event->cgrp. Must be done before
	 * calling add_event_to_ctx()
	 */
	update_cgrp_time_from_event(event);
T
Thomas Gleixner 已提交
1877

1878
	add_event_to_ctx(event, ctx);
T
Thomas Gleixner 已提交
1879

1880
	/*
1881
	 * Schedule everything back in
1882
	 */
1883
	perf_event_sched_in(cpuctx, task_ctx, task);
1884 1885 1886

	perf_pmu_enable(cpuctx->ctx.pmu);
	perf_ctx_unlock(cpuctx, task_ctx);
1887 1888

	return 0;
T
Thomas Gleixner 已提交
1889 1890 1891
}

/*
1892
 * Attach a performance event to a context
T
Thomas Gleixner 已提交
1893
 *
1894 1895
 * First we add the event to the list with the hardware enable bit
 * in event->hw_config cleared.
T
Thomas Gleixner 已提交
1896
 *
1897
 * If the event is attached to a task which is on a CPU we use a smp
T
Thomas Gleixner 已提交
1898 1899 1900 1901
 * call to enable it in the task context. The task might have been
 * scheduled away, but we check this in the smp call again.
 */
static void
1902 1903
perf_install_in_context(struct perf_event_context *ctx,
			struct perf_event *event,
T
Thomas Gleixner 已提交
1904 1905 1906 1907
			int cpu)
{
	struct task_struct *task = ctx->task;

1908 1909
	lockdep_assert_held(&ctx->mutex);

1910
	event->ctx = ctx;
1911 1912
	if (event->cpu != -1)
		event->cpu = cpu;
1913

T
Thomas Gleixner 已提交
1914 1915
	if (!task) {
		/*
1916
		 * Per cpu events are installed via an smp call and
1917
		 * the install is always successful.
T
Thomas Gleixner 已提交
1918
		 */
1919
		cpu_function_call(cpu, __perf_install_in_context, event);
T
Thomas Gleixner 已提交
1920 1921 1922 1923
		return;
	}

retry:
1924 1925
	if (!task_function_call(task, __perf_install_in_context, event))
		return;
T
Thomas Gleixner 已提交
1926

1927
	raw_spin_lock_irq(&ctx->lock);
T
Thomas Gleixner 已提交
1928
	/*
1929 1930
	 * If we failed to find a running task, but find the context active now
	 * that we've acquired the ctx->lock, retry.
T
Thomas Gleixner 已提交
1931
	 */
1932
	if (ctx->is_active) {
1933
		raw_spin_unlock_irq(&ctx->lock);
T
Thomas Gleixner 已提交
1934 1935 1936 1937
		goto retry;
	}

	/*
1938 1939
	 * Since the task isn't running, its safe to add the event, us holding
	 * the ctx->lock ensures the task won't get scheduled in.
T
Thomas Gleixner 已提交
1940
	 */
1941
	add_event_to_ctx(event, ctx);
1942
	raw_spin_unlock_irq(&ctx->lock);
T
Thomas Gleixner 已提交
1943 1944
}

1945
/*
1946
 * Put a event into inactive state and update time fields.
1947 1948 1949 1950 1951 1952
 * 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.
 */
1953
static void __perf_event_mark_enabled(struct perf_event *event)
1954
{
1955
	struct perf_event *sub;
1956
	u64 tstamp = perf_event_time(event);
1957

1958
	event->state = PERF_EVENT_STATE_INACTIVE;
1959
	event->tstamp_enabled = tstamp - event->total_time_enabled;
P
Peter Zijlstra 已提交
1960
	list_for_each_entry(sub, &event->sibling_list, group_entry) {
1961 1962
		if (sub->state >= PERF_EVENT_STATE_INACTIVE)
			sub->tstamp_enabled = tstamp - sub->total_time_enabled;
P
Peter Zijlstra 已提交
1963
	}
1964 1965
}

1966
/*
1967
 * Cross CPU call to enable a performance event
1968
 */
1969
static int __perf_event_enable(void *info)
1970
{
1971 1972 1973
	struct perf_event *event = info;
	struct perf_event_context *ctx = event->ctx;
	struct perf_event *leader = event->group_leader;
P
Peter Zijlstra 已提交
1974
	struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
1975
	int err;
1976

1977 1978 1979 1980 1981 1982 1983 1984 1985 1986
	/*
	 * There's a time window between 'ctx->is_active' check
	 * in perf_event_enable function and this place having:
	 *   - IRQs on
	 *   - ctx->lock unlocked
	 *
	 * where the task could be killed and 'ctx' deactivated
	 * by perf_event_exit_task.
	 */
	if (!ctx->is_active)
1987
		return -EINVAL;
1988

1989
	raw_spin_lock(&ctx->lock);
1990
	update_context_time(ctx);
1991

1992
	if (event->state >= PERF_EVENT_STATE_INACTIVE)
1993
		goto unlock;
S
Stephane Eranian 已提交
1994 1995 1996 1997

	/*
	 * set current task's cgroup time reference point
	 */
1998
	perf_cgroup_set_timestamp(current, ctx);
S
Stephane Eranian 已提交
1999

2000
	__perf_event_mark_enabled(event);
2001

S
Stephane Eranian 已提交
2002 2003 2004
	if (!event_filter_match(event)) {
		if (is_cgroup_event(event))
			perf_cgroup_defer_enabled(event);
2005
		goto unlock;
S
Stephane Eranian 已提交
2006
	}
2007

2008
	/*
2009
	 * If the event is in a group and isn't the group leader,
2010
	 * then don't put it on unless the group is on.
2011
	 */
2012
	if (leader != event && leader->state != PERF_EVENT_STATE_ACTIVE)
2013
		goto unlock;
2014

2015
	if (!group_can_go_on(event, cpuctx, 1)) {
2016
		err = -EEXIST;
2017
	} else {
2018
		if (event == leader)
2019
			err = group_sched_in(event, cpuctx, ctx);
2020
		else
2021
			err = event_sched_in(event, cpuctx, ctx);
2022
	}
2023 2024 2025

	if (err) {
		/*
2026
		 * If this event can't go on and it's part of a
2027 2028
		 * group, then the whole group has to come off.
		 */
2029
		if (leader != event) {
2030
			group_sched_out(leader, cpuctx, ctx);
2031 2032
			perf_cpu_hrtimer_restart(cpuctx);
		}
2033
		if (leader->attr.pinned) {
2034
			update_group_times(leader);
2035
			leader->state = PERF_EVENT_STATE_ERROR;
2036
		}
2037 2038
	}

P
Peter Zijlstra 已提交
2039
unlock:
2040
	raw_spin_unlock(&ctx->lock);
2041 2042

	return 0;
2043 2044 2045
}

/*
2046
 * Enable a event.
2047
 *
2048 2049
 * If event->ctx is a cloned context, callers must make sure that
 * every task struct that event->ctx->task could possibly point to
2050
 * remains valid.  This condition is satisfied when called through
2051 2052
 * perf_event_for_each_child or perf_event_for_each as described
 * for perf_event_disable.
2053
 */
2054
void perf_event_enable(struct perf_event *event)
2055
{
2056
	struct perf_event_context *ctx = event->ctx;
2057 2058 2059 2060
	struct task_struct *task = ctx->task;

	if (!task) {
		/*
2061
		 * Enable the event on the cpu that it's on
2062
		 */
2063
		cpu_function_call(event->cpu, __perf_event_enable, event);
2064 2065 2066
		return;
	}

2067
	raw_spin_lock_irq(&ctx->lock);
2068
	if (event->state >= PERF_EVENT_STATE_INACTIVE)
2069 2070 2071
		goto out;

	/*
2072 2073
	 * If the event is in error state, clear that first.
	 * That way, if we see the event in error state below, we
2074 2075 2076 2077
	 * know that it has gone back into error state, as distinct
	 * from the task having been scheduled away before the
	 * cross-call arrived.
	 */
2078 2079
	if (event->state == PERF_EVENT_STATE_ERROR)
		event->state = PERF_EVENT_STATE_OFF;
2080

P
Peter Zijlstra 已提交
2081
retry:
2082
	if (!ctx->is_active) {
2083
		__perf_event_mark_enabled(event);
2084 2085 2086
		goto out;
	}

2087
	raw_spin_unlock_irq(&ctx->lock);
2088 2089 2090

	if (!task_function_call(task, __perf_event_enable, event))
		return;
2091

2092
	raw_spin_lock_irq(&ctx->lock);
2093 2094

	/*
2095
	 * If the context is active and the event is still off,
2096 2097
	 * we need to retry the cross-call.
	 */
2098 2099 2100 2101 2102 2103
	if (ctx->is_active && event->state == PERF_EVENT_STATE_OFF) {
		/*
		 * task could have been flipped by a concurrent
		 * perf_event_context_sched_out()
		 */
		task = ctx->task;
2104
		goto retry;
2105
	}
2106

P
Peter Zijlstra 已提交
2107
out:
2108
	raw_spin_unlock_irq(&ctx->lock);
2109
}
2110
EXPORT_SYMBOL_GPL(perf_event_enable);
2111

2112
int perf_event_refresh(struct perf_event *event, int refresh)
2113
{
2114
	/*
2115
	 * not supported on inherited events
2116
	 */
2117
	if (event->attr.inherit || !is_sampling_event(event))
2118 2119
		return -EINVAL;

2120 2121
	atomic_add(refresh, &event->event_limit);
	perf_event_enable(event);
2122 2123

	return 0;
2124
}
2125
EXPORT_SYMBOL_GPL(perf_event_refresh);
2126

2127 2128 2129
static void ctx_sched_out(struct perf_event_context *ctx,
			  struct perf_cpu_context *cpuctx,
			  enum event_type_t event_type)
2130
{
2131
	struct perf_event *event;
2132
	int is_active = ctx->is_active;
2133

2134
	ctx->is_active &= ~event_type;
2135
	if (likely(!ctx->nr_events))
2136 2137
		return;

2138
	update_context_time(ctx);
S
Stephane Eranian 已提交
2139
	update_cgrp_time_from_cpuctx(cpuctx);
2140
	if (!ctx->nr_active)
2141
		return;
2142

P
Peter Zijlstra 已提交
2143
	perf_pmu_disable(ctx->pmu);
2144
	if ((is_active & EVENT_PINNED) && (event_type & EVENT_PINNED)) {
2145 2146
		list_for_each_entry(event, &ctx->pinned_groups, group_entry)
			group_sched_out(event, cpuctx, ctx);
P
Peter Zijlstra 已提交
2147
	}
2148

2149
	if ((is_active & EVENT_FLEXIBLE) && (event_type & EVENT_FLEXIBLE)) {
2150
		list_for_each_entry(event, &ctx->flexible_groups, group_entry)
2151
			group_sched_out(event, cpuctx, ctx);
P
Peter Zijlstra 已提交
2152
	}
P
Peter Zijlstra 已提交
2153
	perf_pmu_enable(ctx->pmu);
2154 2155
}

2156
/*
2157 2158 2159 2160 2161 2162
 * 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().
2163
 */
2164 2165
static int context_equiv(struct perf_event_context *ctx1,
			 struct perf_event_context *ctx2)
2166
{
2167 2168 2169 2170 2171 2172 2173 2174 2175 2176 2177 2178 2179 2180 2181 2182 2183 2184 2185 2186 2187 2188
	/* 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;
2189 2190
}

2191 2192
static void __perf_event_sync_stat(struct perf_event *event,
				     struct perf_event *next_event)
2193 2194 2195
{
	u64 value;

2196
	if (!event->attr.inherit_stat)
2197 2198 2199
		return;

	/*
2200
	 * Update the event value, we cannot use perf_event_read()
2201 2202
	 * because we're in the middle of a context switch and have IRQs
	 * disabled, which upsets smp_call_function_single(), however
2203
	 * we know the event must be on the current CPU, therefore we
2204 2205
	 * don't need to use it.
	 */
2206 2207
	switch (event->state) {
	case PERF_EVENT_STATE_ACTIVE:
2208 2209
		event->pmu->read(event);
		/* fall-through */
2210

2211 2212
	case PERF_EVENT_STATE_INACTIVE:
		update_event_times(event);
2213 2214 2215 2216 2217 2218 2219
		break;

	default:
		break;
	}

	/*
2220
	 * In order to keep per-task stats reliable we need to flip the event
2221 2222
	 * values when we flip the contexts.
	 */
2223 2224 2225
	value = local64_read(&next_event->count);
	value = local64_xchg(&event->count, value);
	local64_set(&next_event->count, value);
2226

2227 2228
	swap(event->total_time_enabled, next_event->total_time_enabled);
	swap(event->total_time_running, next_event->total_time_running);
2229

2230
	/*
2231
	 * Since we swizzled the values, update the user visible data too.
2232
	 */
2233 2234
	perf_event_update_userpage(event);
	perf_event_update_userpage(next_event);
2235 2236
}

2237 2238
static void perf_event_sync_stat(struct perf_event_context *ctx,
				   struct perf_event_context *next_ctx)
2239
{
2240
	struct perf_event *event, *next_event;
2241 2242 2243 2244

	if (!ctx->nr_stat)
		return;

2245 2246
	update_context_time(ctx);

2247 2248
	event = list_first_entry(&ctx->event_list,
				   struct perf_event, event_entry);
2249

2250 2251
	next_event = list_first_entry(&next_ctx->event_list,
					struct perf_event, event_entry);
2252

2253 2254
	while (&event->event_entry != &ctx->event_list &&
	       &next_event->event_entry != &next_ctx->event_list) {
2255

2256
		__perf_event_sync_stat(event, next_event);
2257

2258 2259
		event = list_next_entry(event, event_entry);
		next_event = list_next_entry(next_event, event_entry);
2260 2261 2262
	}
}

2263 2264
static void perf_event_context_sched_out(struct task_struct *task, int ctxn,
					 struct task_struct *next)
T
Thomas Gleixner 已提交
2265
{
P
Peter Zijlstra 已提交
2266
	struct perf_event_context *ctx = task->perf_event_ctxp[ctxn];
2267
	struct perf_event_context *next_ctx;
2268
	struct perf_event_context *parent, *next_parent;
P
Peter Zijlstra 已提交
2269
	struct perf_cpu_context *cpuctx;
2270
	int do_switch = 1;
T
Thomas Gleixner 已提交
2271

P
Peter Zijlstra 已提交
2272 2273
	if (likely(!ctx))
		return;
2274

P
Peter Zijlstra 已提交
2275 2276
	cpuctx = __get_cpu_context(ctx);
	if (!cpuctx->task_ctx)
T
Thomas Gleixner 已提交
2277 2278
		return;

2279
	rcu_read_lock();
P
Peter Zijlstra 已提交
2280
	next_ctx = next->perf_event_ctxp[ctxn];
2281 2282 2283 2284 2285 2286 2287 2288 2289 2290 2291
	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. */
	if (!parent && !next_parent)
		goto unlock;

	if (next_parent == ctx || next_ctx == parent || next_parent == parent) {
2292 2293 2294 2295 2296 2297 2298 2299 2300
		/*
		 * 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.
		 */
2301 2302
		raw_spin_lock(&ctx->lock);
		raw_spin_lock_nested(&next_ctx->lock, SINGLE_DEPTH_NESTING);
2303
		if (context_equiv(ctx, next_ctx)) {
2304 2305
			/*
			 * XXX do we need a memory barrier of sorts
2306
			 * wrt to rcu_dereference() of perf_event_ctxp
2307
			 */
P
Peter Zijlstra 已提交
2308 2309
			task->perf_event_ctxp[ctxn] = next_ctx;
			next->perf_event_ctxp[ctxn] = ctx;
2310 2311 2312
			ctx->task = next;
			next_ctx->task = task;
			do_switch = 0;
2313

2314
			perf_event_sync_stat(ctx, next_ctx);
2315
		}
2316 2317
		raw_spin_unlock(&next_ctx->lock);
		raw_spin_unlock(&ctx->lock);
2318
	}
2319
unlock:
2320
	rcu_read_unlock();
2321

2322
	if (do_switch) {
2323
		raw_spin_lock(&ctx->lock);
2324
		ctx_sched_out(ctx, cpuctx, EVENT_ALL);
2325
		cpuctx->task_ctx = NULL;
2326
		raw_spin_unlock(&ctx->lock);
2327
	}
T
Thomas Gleixner 已提交
2328 2329
}

P
Peter Zijlstra 已提交
2330 2331 2332 2333 2334 2335 2336 2337 2338 2339 2340 2341 2342 2343
#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.
 */
2344 2345
void __perf_event_task_sched_out(struct task_struct *task,
				 struct task_struct *next)
P
Peter Zijlstra 已提交
2346 2347 2348 2349 2350
{
	int ctxn;

	for_each_task_context_nr(ctxn)
		perf_event_context_sched_out(task, ctxn, next);
S
Stephane Eranian 已提交
2351 2352 2353 2354 2355 2356 2357

	/*
	 * 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
	 */
	if (atomic_read(&__get_cpu_var(perf_cgroup_events)))
2358
		perf_cgroup_sched_out(task, next);
P
Peter Zijlstra 已提交
2359 2360
}

2361
static void task_ctx_sched_out(struct perf_event_context *ctx)
2362
{
P
Peter Zijlstra 已提交
2363
	struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
2364

2365 2366
	if (!cpuctx->task_ctx)
		return;
2367 2368 2369 2370

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

2371
	ctx_sched_out(ctx, cpuctx, EVENT_ALL);
2372 2373 2374
	cpuctx->task_ctx = NULL;
}

2375 2376 2377 2378 2379 2380 2381
/*
 * 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);
2382 2383
}

2384
static void
2385
ctx_pinned_sched_in(struct perf_event_context *ctx,
2386
		    struct perf_cpu_context *cpuctx)
T
Thomas Gleixner 已提交
2387
{
2388
	struct perf_event *event;
T
Thomas Gleixner 已提交
2389

2390 2391
	list_for_each_entry(event, &ctx->pinned_groups, group_entry) {
		if (event->state <= PERF_EVENT_STATE_OFF)
2392
			continue;
2393
		if (!event_filter_match(event))
2394 2395
			continue;

S
Stephane Eranian 已提交
2396 2397 2398 2399
		/* may need to reset tstamp_enabled */
		if (is_cgroup_event(event))
			perf_cgroup_mark_enabled(event, ctx);

2400
		if (group_can_go_on(event, cpuctx, 1))
2401
			group_sched_in(event, cpuctx, ctx);
2402 2403 2404 2405 2406

		/*
		 * If this pinned group hasn't been scheduled,
		 * put it in error state.
		 */
2407 2408 2409
		if (event->state == PERF_EVENT_STATE_INACTIVE) {
			update_group_times(event);
			event->state = PERF_EVENT_STATE_ERROR;
2410
		}
2411
	}
2412 2413 2414 2415
}

static void
ctx_flexible_sched_in(struct perf_event_context *ctx,
2416
		      struct perf_cpu_context *cpuctx)
2417 2418 2419
{
	struct perf_event *event;
	int can_add_hw = 1;
2420

2421 2422 2423
	list_for_each_entry(event, &ctx->flexible_groups, group_entry) {
		/* Ignore events in OFF or ERROR state */
		if (event->state <= PERF_EVENT_STATE_OFF)
2424
			continue;
2425 2426
		/*
		 * Listen to the 'cpu' scheduling filter constraint
2427
		 * of events:
2428
		 */
2429
		if (!event_filter_match(event))
T
Thomas Gleixner 已提交
2430 2431
			continue;

S
Stephane Eranian 已提交
2432 2433 2434 2435
		/* may need to reset tstamp_enabled */
		if (is_cgroup_event(event))
			perf_cgroup_mark_enabled(event, ctx);

P
Peter Zijlstra 已提交
2436
		if (group_can_go_on(event, cpuctx, can_add_hw)) {
2437
			if (group_sched_in(event, cpuctx, ctx))
2438
				can_add_hw = 0;
P
Peter Zijlstra 已提交
2439
		}
T
Thomas Gleixner 已提交
2440
	}
2441 2442 2443 2444 2445
}

static void
ctx_sched_in(struct perf_event_context *ctx,
	     struct perf_cpu_context *cpuctx,
S
Stephane Eranian 已提交
2446 2447
	     enum event_type_t event_type,
	     struct task_struct *task)
2448
{
S
Stephane Eranian 已提交
2449
	u64 now;
2450
	int is_active = ctx->is_active;
S
Stephane Eranian 已提交
2451

2452
	ctx->is_active |= event_type;
2453
	if (likely(!ctx->nr_events))
2454
		return;
2455

S
Stephane Eranian 已提交
2456 2457
	now = perf_clock();
	ctx->timestamp = now;
2458
	perf_cgroup_set_timestamp(task, ctx);
2459 2460 2461 2462
	/*
	 * First go through the list and put on any pinned groups
	 * in order to give them the best chance of going on.
	 */
2463
	if (!(is_active & EVENT_PINNED) && (event_type & EVENT_PINNED))
2464
		ctx_pinned_sched_in(ctx, cpuctx);
2465 2466

	/* Then walk through the lower prio flexible groups */
2467
	if (!(is_active & EVENT_FLEXIBLE) && (event_type & EVENT_FLEXIBLE))
2468
		ctx_flexible_sched_in(ctx, cpuctx);
2469 2470
}

2471
static void cpu_ctx_sched_in(struct perf_cpu_context *cpuctx,
S
Stephane Eranian 已提交
2472 2473
			     enum event_type_t event_type,
			     struct task_struct *task)
2474 2475 2476
{
	struct perf_event_context *ctx = &cpuctx->ctx;

S
Stephane Eranian 已提交
2477
	ctx_sched_in(ctx, cpuctx, event_type, task);
2478 2479
}

S
Stephane Eranian 已提交
2480 2481
static void perf_event_context_sched_in(struct perf_event_context *ctx,
					struct task_struct *task)
2482
{
P
Peter Zijlstra 已提交
2483
	struct perf_cpu_context *cpuctx;
2484

P
Peter Zijlstra 已提交
2485
	cpuctx = __get_cpu_context(ctx);
2486 2487 2488
	if (cpuctx->task_ctx == ctx)
		return;

2489
	perf_ctx_lock(cpuctx, ctx);
P
Peter Zijlstra 已提交
2490
	perf_pmu_disable(ctx->pmu);
2491 2492 2493 2494 2495 2496 2497
	/*
	 * 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);

2498 2499
	if (ctx->nr_events)
		cpuctx->task_ctx = ctx;
2500

2501 2502
	perf_event_sched_in(cpuctx, cpuctx->task_ctx, task);

2503 2504 2505
	perf_pmu_enable(ctx->pmu);
	perf_ctx_unlock(cpuctx, ctx);

2506 2507 2508 2509
	/*
	 * Since these rotations are per-cpu, we need to ensure the
	 * cpu-context we got scheduled on is actually rotating.
	 */
P
Peter Zijlstra 已提交
2510
	perf_pmu_rotate_start(ctx->pmu);
2511 2512
}

2513 2514 2515 2516 2517 2518 2519 2520 2521 2522 2523 2524 2525 2526 2527 2528 2529 2530 2531 2532 2533 2534 2535 2536 2537 2538 2539 2540 2541 2542 2543 2544 2545 2546 2547 2548 2549 2550 2551 2552 2553 2554 2555 2556 2557 2558 2559 2560 2561 2562 2563 2564 2565 2566 2567 2568 2569 2570 2571 2572
/*
 * When sampling the branck stack in system-wide, it may be necessary
 * to flush the stack on context switch. This happens when the branch
 * stack does not tag its entries with the pid of the current task.
 * Otherwise it becomes impossible to associate a branch entry with a
 * task. This ambiguity is more likely to appear when the branch stack
 * supports priv level filtering and the user sets it to monitor only
 * at the user level (which could be a useful measurement in system-wide
 * mode). In that case, the risk is high of having a branch stack with
 * branch from multiple tasks. Flushing may mean dropping the existing
 * entries or stashing them somewhere in the PMU specific code layer.
 *
 * This function provides the context switch callback to the lower code
 * layer. It is invoked ONLY when there is at least one system-wide context
 * with at least one active event using taken branch sampling.
 */
static void perf_branch_stack_sched_in(struct task_struct *prev,
				       struct task_struct *task)
{
	struct perf_cpu_context *cpuctx;
	struct pmu *pmu;
	unsigned long flags;

	/* no need to flush branch stack if not changing task */
	if (prev == task)
		return;

	local_irq_save(flags);

	rcu_read_lock();

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

		/*
		 * check if the context has at least one
		 * event using PERF_SAMPLE_BRANCH_STACK
		 */
		if (cpuctx->ctx.nr_branch_stack > 0
		    && pmu->flush_branch_stack) {

			pmu = cpuctx->ctx.pmu;

			perf_ctx_lock(cpuctx, cpuctx->task_ctx);

			perf_pmu_disable(pmu);

			pmu->flush_branch_stack();

			perf_pmu_enable(pmu);

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

	rcu_read_unlock();

	local_irq_restore(flags);
}

P
Peter Zijlstra 已提交
2573 2574 2575 2576 2577 2578 2579 2580 2581 2582 2583
/*
 * 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.
 */
2584 2585
void __perf_event_task_sched_in(struct task_struct *prev,
				struct task_struct *task)
P
Peter Zijlstra 已提交
2586 2587 2588 2589 2590 2591 2592 2593 2594
{
	struct perf_event_context *ctx;
	int ctxn;

	for_each_task_context_nr(ctxn) {
		ctx = task->perf_event_ctxp[ctxn];
		if (likely(!ctx))
			continue;

S
Stephane Eranian 已提交
2595
		perf_event_context_sched_in(ctx, task);
P
Peter Zijlstra 已提交
2596
	}
S
Stephane Eranian 已提交
2597 2598 2599 2600 2601 2602
	/*
	 * 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
	 */
	if (atomic_read(&__get_cpu_var(perf_cgroup_events)))
2603
		perf_cgroup_sched_in(prev, task);
2604 2605 2606 2607

	/* check for system-wide branch_stack events */
	if (atomic_read(&__get_cpu_var(perf_branch_stack_events)))
		perf_branch_stack_sched_in(prev, task);
2608 2609
}

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
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.
	 */
2637
#define REDUCE_FLS(a, b)		\
2638 2639 2640 2641 2642 2643 2644 2645 2646 2647 2648 2649 2650 2651 2652 2653 2654 2655 2656 2657 2658 2659 2660 2661 2662 2663 2664 2665 2666 2667 2668 2669 2670 2671 2672 2673 2674 2675 2676
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;
	}

2677 2678 2679
	if (!divisor)
		return dividend;

2680 2681 2682
	return div64_u64(dividend, divisor);
}

2683 2684 2685
static DEFINE_PER_CPU(int, perf_throttled_count);
static DEFINE_PER_CPU(u64, perf_throttled_seq);

2686
static void perf_adjust_period(struct perf_event *event, u64 nsec, u64 count, bool disable)
2687
{
2688
	struct hw_perf_event *hwc = &event->hw;
2689
	s64 period, sample_period;
2690 2691
	s64 delta;

2692
	period = perf_calculate_period(event, nsec, count);
2693 2694 2695 2696 2697 2698 2699 2700 2701 2702

	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;
2703

2704
	if (local64_read(&hwc->period_left) > 8*sample_period) {
2705 2706 2707
		if (disable)
			event->pmu->stop(event, PERF_EF_UPDATE);

2708
		local64_set(&hwc->period_left, 0);
2709 2710 2711

		if (disable)
			event->pmu->start(event, PERF_EF_RELOAD);
2712
	}
2713 2714
}

2715 2716 2717 2718 2719 2720 2721
/*
 * 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)
2722
{
2723 2724
	struct perf_event *event;
	struct hw_perf_event *hwc;
2725
	u64 now, period = TICK_NSEC;
2726
	s64 delta;
2727

2728 2729 2730 2731 2732 2733
	/*
	 * 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))
2734 2735
		return;

2736
	raw_spin_lock(&ctx->lock);
2737
	perf_pmu_disable(ctx->pmu);
2738

2739
	list_for_each_entry_rcu(event, &ctx->event_list, event_entry) {
2740
		if (event->state != PERF_EVENT_STATE_ACTIVE)
2741 2742
			continue;

2743
		if (!event_filter_match(event))
2744 2745
			continue;

2746
		hwc = &event->hw;
2747

2748
		if (hwc->interrupts == MAX_INTERRUPTS) {
2749
			hwc->interrupts = 0;
2750
			perf_log_throttle(event, 1);
P
Peter Zijlstra 已提交
2751
			event->pmu->start(event, 0);
2752 2753
		}

2754
		if (!event->attr.freq || !event->attr.sample_freq)
2755 2756
			continue;

2757 2758 2759 2760 2761
		/*
		 * stop the event and update event->count
		 */
		event->pmu->stop(event, PERF_EF_UPDATE);

2762
		now = local64_read(&event->count);
2763 2764
		delta = now - hwc->freq_count_stamp;
		hwc->freq_count_stamp = now;
2765

2766 2767 2768
		/*
		 * restart the event
		 * reload only if value has changed
2769 2770 2771
		 * we have stopped the event so tell that
		 * to perf_adjust_period() to avoid stopping it
		 * twice.
2772
		 */
2773
		if (delta > 0)
2774
			perf_adjust_period(event, period, delta, false);
2775 2776

		event->pmu->start(event, delta > 0 ? PERF_EF_RELOAD : 0);
2777
	}
2778

2779
	perf_pmu_enable(ctx->pmu);
2780
	raw_spin_unlock(&ctx->lock);
2781 2782
}

2783
/*
2784
 * Round-robin a context's events:
2785
 */
2786
static void rotate_ctx(struct perf_event_context *ctx)
T
Thomas Gleixner 已提交
2787
{
2788 2789 2790 2791 2792 2793
	/*
	 * 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);
2794 2795
}

2796
/*
2797 2798 2799
 * perf_pmu_rotate_start() and perf_rotate_context() are fully serialized
 * because they're strictly cpu affine and rotate_start is called with IRQs
 * disabled, while rotate_context is called from IRQ context.
2800
 */
2801
static int perf_rotate_context(struct perf_cpu_context *cpuctx)
2802
{
P
Peter Zijlstra 已提交
2803
	struct perf_event_context *ctx = NULL;
2804
	int rotate = 0, remove = 1;
2805

2806
	if (cpuctx->ctx.nr_events) {
2807
		remove = 0;
2808 2809 2810
		if (cpuctx->ctx.nr_events != cpuctx->ctx.nr_active)
			rotate = 1;
	}
2811

P
Peter Zijlstra 已提交
2812
	ctx = cpuctx->task_ctx;
2813
	if (ctx && ctx->nr_events) {
2814
		remove = 0;
2815 2816 2817
		if (ctx->nr_events != ctx->nr_active)
			rotate = 1;
	}
2818

2819
	if (!rotate)
2820 2821
		goto done;

2822
	perf_ctx_lock(cpuctx, cpuctx->task_ctx);
P
Peter Zijlstra 已提交
2823
	perf_pmu_disable(cpuctx->ctx.pmu);
2824

2825 2826 2827
	cpu_ctx_sched_out(cpuctx, EVENT_FLEXIBLE);
	if (ctx)
		ctx_sched_out(ctx, cpuctx, EVENT_FLEXIBLE);
T
Thomas Gleixner 已提交
2828

2829 2830 2831
	rotate_ctx(&cpuctx->ctx);
	if (ctx)
		rotate_ctx(ctx);
2832

2833
	perf_event_sched_in(cpuctx, ctx, current);
2834

2835 2836
	perf_pmu_enable(cpuctx->ctx.pmu);
	perf_ctx_unlock(cpuctx, cpuctx->task_ctx);
2837
done:
2838 2839
	if (remove)
		list_del_init(&cpuctx->rotation_list);
2840 2841

	return rotate;
2842 2843
}

2844 2845 2846
#ifdef CONFIG_NO_HZ_FULL
bool perf_event_can_stop_tick(void)
{
2847
	if (atomic_read(&nr_freq_events) ||
2848
	    __this_cpu_read(perf_throttled_count))
2849
		return false;
2850 2851
	else
		return true;
2852 2853 2854
}
#endif

2855 2856 2857 2858
void perf_event_task_tick(void)
{
	struct list_head *head = &__get_cpu_var(rotation_list);
	struct perf_cpu_context *cpuctx, *tmp;
2859 2860
	struct perf_event_context *ctx;
	int throttled;
2861

2862 2863
	WARN_ON(!irqs_disabled());

2864 2865 2866
	__this_cpu_inc(perf_throttled_seq);
	throttled = __this_cpu_xchg(perf_throttled_count, 0);

2867
	list_for_each_entry_safe(cpuctx, tmp, head, rotation_list) {
2868 2869 2870 2871 2872 2873
		ctx = &cpuctx->ctx;
		perf_adjust_freq_unthr_context(ctx, throttled);

		ctx = cpuctx->task_ctx;
		if (ctx)
			perf_adjust_freq_unthr_context(ctx, throttled);
2874
	}
T
Thomas Gleixner 已提交
2875 2876
}

2877 2878 2879 2880 2881 2882 2883 2884 2885 2886
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;

2887
	__perf_event_mark_enabled(event);
2888 2889 2890 2891

	return 1;
}

2892
/*
2893
 * Enable all of a task's events that have been marked enable-on-exec.
2894 2895
 * This expects task == current.
 */
P
Peter Zijlstra 已提交
2896
static void perf_event_enable_on_exec(struct perf_event_context *ctx)
2897
{
2898
	struct perf_event *event;
2899 2900
	unsigned long flags;
	int enabled = 0;
2901
	int ret;
2902 2903

	local_irq_save(flags);
2904
	if (!ctx || !ctx->nr_events)
2905 2906
		goto out;

2907 2908 2909 2910 2911 2912 2913
	/*
	 * We must ctxsw out cgroup events to avoid conflict
	 * when invoking perf_task_event_sched_in() later on
	 * in this function. Otherwise we end up trying to
	 * ctxswin cgroup events which are already scheduled
	 * in.
	 */
2914
	perf_cgroup_sched_out(current, NULL);
2915

2916
	raw_spin_lock(&ctx->lock);
2917
	task_ctx_sched_out(ctx);
2918

2919
	list_for_each_entry(event, &ctx->event_list, event_entry) {
2920 2921 2922
		ret = event_enable_on_exec(event, ctx);
		if (ret)
			enabled = 1;
2923 2924 2925
	}

	/*
2926
	 * Unclone this context if we enabled any event.
2927
	 */
2928 2929
	if (enabled)
		unclone_ctx(ctx);
2930

2931
	raw_spin_unlock(&ctx->lock);
2932

2933 2934 2935
	/*
	 * Also calls ctxswin for cgroup events, if any:
	 */
S
Stephane Eranian 已提交
2936
	perf_event_context_sched_in(ctx, ctx->task);
P
Peter Zijlstra 已提交
2937
out:
2938 2939 2940
	local_irq_restore(flags);
}

T
Thomas Gleixner 已提交
2941
/*
2942
 * Cross CPU call to read the hardware event
T
Thomas Gleixner 已提交
2943
 */
2944
static void __perf_event_read(void *info)
T
Thomas Gleixner 已提交
2945
{
2946 2947
	struct perf_event *event = info;
	struct perf_event_context *ctx = event->ctx;
P
Peter Zijlstra 已提交
2948
	struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
I
Ingo Molnar 已提交
2949

2950 2951 2952 2953
	/*
	 * 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
2954 2955
	 * event->count would have been updated to a recent sample
	 * when the event was scheduled out.
2956 2957 2958 2959
	 */
	if (ctx->task && cpuctx->task_ctx != ctx)
		return;

2960
	raw_spin_lock(&ctx->lock);
S
Stephane Eranian 已提交
2961
	if (ctx->is_active) {
2962
		update_context_time(ctx);
S
Stephane Eranian 已提交
2963 2964
		update_cgrp_time_from_event(event);
	}
2965
	update_event_times(event);
2966 2967
	if (event->state == PERF_EVENT_STATE_ACTIVE)
		event->pmu->read(event);
2968
	raw_spin_unlock(&ctx->lock);
T
Thomas Gleixner 已提交
2969 2970
}

P
Peter Zijlstra 已提交
2971 2972
static inline u64 perf_event_count(struct perf_event *event)
{
2973
	return local64_read(&event->count) + atomic64_read(&event->child_count);
P
Peter Zijlstra 已提交
2974 2975
}

2976
static u64 perf_event_read(struct perf_event *event)
T
Thomas Gleixner 已提交
2977 2978
{
	/*
2979 2980
	 * If event is enabled and currently active on a CPU, update the
	 * value in the event structure:
T
Thomas Gleixner 已提交
2981
	 */
2982 2983 2984 2985
	if (event->state == PERF_EVENT_STATE_ACTIVE) {
		smp_call_function_single(event->oncpu,
					 __perf_event_read, event, 1);
	} else if (event->state == PERF_EVENT_STATE_INACTIVE) {
P
Peter Zijlstra 已提交
2986 2987 2988
		struct perf_event_context *ctx = event->ctx;
		unsigned long flags;

2989
		raw_spin_lock_irqsave(&ctx->lock, flags);
2990 2991 2992 2993 2994
		/*
		 * 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
2995
		if (ctx->is_active) {
2996
			update_context_time(ctx);
S
Stephane Eranian 已提交
2997 2998
			update_cgrp_time_from_event(event);
		}
2999
		update_event_times(event);
3000
		raw_spin_unlock_irqrestore(&ctx->lock, flags);
T
Thomas Gleixner 已提交
3001 3002
	}

P
Peter Zijlstra 已提交
3003
	return perf_event_count(event);
T
Thomas Gleixner 已提交
3004 3005
}

3006
/*
3007
 * Initialize the perf_event context in a task_struct:
3008
 */
3009
static void __perf_event_init_context(struct perf_event_context *ctx)
3010
{
3011
	raw_spin_lock_init(&ctx->lock);
3012
	mutex_init(&ctx->mutex);
3013 3014
	INIT_LIST_HEAD(&ctx->pinned_groups);
	INIT_LIST_HEAD(&ctx->flexible_groups);
3015 3016
	INIT_LIST_HEAD(&ctx->event_list);
	atomic_set(&ctx->refcount, 1);
3017 3018 3019 3020 3021 3022 3023 3024 3025 3026 3027 3028 3029 3030 3031
}

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
3032
	}
3033 3034 3035
	ctx->pmu = pmu;

	return ctx;
3036 3037
}

3038 3039 3040 3041 3042
static struct task_struct *
find_lively_task_by_vpid(pid_t vpid)
{
	struct task_struct *task;
	int err;
T
Thomas Gleixner 已提交
3043 3044

	rcu_read_lock();
3045
	if (!vpid)
T
Thomas Gleixner 已提交
3046 3047
		task = current;
	else
3048
		task = find_task_by_vpid(vpid);
T
Thomas Gleixner 已提交
3049 3050 3051 3052 3053 3054 3055 3056
	if (task)
		get_task_struct(task);
	rcu_read_unlock();

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

	/* Reuse ptrace permission checks for now. */
3057 3058 3059 3060
	err = -EACCES;
	if (!ptrace_may_access(task, PTRACE_MODE_READ))
		goto errout;

3061 3062 3063 3064 3065 3066 3067
	return task;
errout:
	put_task_struct(task);
	return ERR_PTR(err);

}

3068 3069 3070
/*
 * Returns a matching context with refcount and pincount.
 */
P
Peter Zijlstra 已提交
3071
static struct perf_event_context *
M
Matt Helsley 已提交
3072
find_get_context(struct pmu *pmu, struct task_struct *task, int cpu)
T
Thomas Gleixner 已提交
3073
{
3074
	struct perf_event_context *ctx;
3075
	struct perf_cpu_context *cpuctx;
3076
	unsigned long flags;
P
Peter Zijlstra 已提交
3077
	int ctxn, err;
T
Thomas Gleixner 已提交
3078

3079
	if (!task) {
3080
		/* Must be root to operate on a CPU event: */
3081
		if (perf_paranoid_cpu() && !capable(CAP_SYS_ADMIN))
T
Thomas Gleixner 已提交
3082 3083 3084
			return ERR_PTR(-EACCES);

		/*
3085
		 * We could be clever and allow to attach a event to an
T
Thomas Gleixner 已提交
3086 3087 3088
		 * offline CPU and activate it when the CPU comes up, but
		 * that's for later.
		 */
3089
		if (!cpu_online(cpu))
T
Thomas Gleixner 已提交
3090 3091
			return ERR_PTR(-ENODEV);

P
Peter Zijlstra 已提交
3092
		cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
T
Thomas Gleixner 已提交
3093
		ctx = &cpuctx->ctx;
3094
		get_ctx(ctx);
3095
		++ctx->pin_count;
T
Thomas Gleixner 已提交
3096 3097 3098 3099

		return ctx;
	}

P
Peter Zijlstra 已提交
3100 3101 3102 3103 3104
	err = -EINVAL;
	ctxn = pmu->task_ctx_nr;
	if (ctxn < 0)
		goto errout;

P
Peter Zijlstra 已提交
3105
retry:
P
Peter Zijlstra 已提交
3106
	ctx = perf_lock_task_context(task, ctxn, &flags);
3107
	if (ctx) {
3108
		unclone_ctx(ctx);
3109
		++ctx->pin_count;
3110
		raw_spin_unlock_irqrestore(&ctx->lock, flags);
3111
	} else {
3112
		ctx = alloc_perf_context(pmu, task);
3113 3114 3115
		err = -ENOMEM;
		if (!ctx)
			goto errout;
3116

3117 3118 3119 3120 3121 3122 3123 3124 3125 3126
		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;
3127
		else {
3128
			get_ctx(ctx);
3129
			++ctx->pin_count;
3130
			rcu_assign_pointer(task->perf_event_ctxp[ctxn], ctx);
3131
		}
3132 3133 3134
		mutex_unlock(&task->perf_event_mutex);

		if (unlikely(err)) {
3135
			put_ctx(ctx);
3136 3137 3138 3139

			if (err == -EAGAIN)
				goto retry;
			goto errout;
3140 3141 3142
		}
	}

T
Thomas Gleixner 已提交
3143
	return ctx;
3144

P
Peter Zijlstra 已提交
3145
errout:
3146
	return ERR_PTR(err);
T
Thomas Gleixner 已提交
3147 3148
}

L
Li Zefan 已提交
3149 3150
static void perf_event_free_filter(struct perf_event *event);

3151
static void free_event_rcu(struct rcu_head *head)
P
Peter Zijlstra 已提交
3152
{
3153
	struct perf_event *event;
P
Peter Zijlstra 已提交
3154

3155 3156 3157
	event = container_of(head, struct perf_event, rcu_head);
	if (event->ns)
		put_pid_ns(event->ns);
L
Li Zefan 已提交
3158
	perf_event_free_filter(event);
3159
	kfree(event);
P
Peter Zijlstra 已提交
3160 3161
}

3162
static void ring_buffer_put(struct ring_buffer *rb);
3163
static void ring_buffer_detach(struct perf_event *event, struct ring_buffer *rb);
3164

3165
static void unaccount_event_cpu(struct perf_event *event, int cpu)
3166
{
3167 3168 3169 3170 3171 3172 3173 3174 3175 3176
	if (event->parent)
		return;

	if (has_branch_stack(event)) {
		if (!(event->attach_state & PERF_ATTACH_TASK))
			atomic_dec(&per_cpu(perf_branch_stack_events, cpu));
	}
	if (is_cgroup_event(event))
		atomic_dec(&per_cpu(perf_cgroup_events, cpu));
}
3177

3178 3179 3180 3181 3182 3183 3184 3185 3186 3187 3188 3189 3190
static void unaccount_event(struct perf_event *event)
{
	if (event->parent)
		return;

	if (event->attach_state & PERF_ATTACH_TASK)
		static_key_slow_dec_deferred(&perf_sched_events);
	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);
3191 3192
	if (event->attr.freq)
		atomic_dec(&nr_freq_events);
3193 3194 3195 3196 3197 3198 3199
	if (is_cgroup_event(event))
		static_key_slow_dec_deferred(&perf_sched_events);
	if (has_branch_stack(event))
		static_key_slow_dec_deferred(&perf_sched_events);

	unaccount_event_cpu(event, event->cpu);
}
3200

3201 3202
static void __free_event(struct perf_event *event)
{
3203
	if (!event->parent) {
3204 3205
		if (event->attr.sample_type & PERF_SAMPLE_CALLCHAIN)
			put_callchain_buffers();
3206
	}
3207

3208 3209 3210 3211 3212 3213 3214 3215
	if (event->destroy)
		event->destroy(event);

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

	call_rcu(&event->rcu_head, free_event_rcu);
}
3216
static void free_event(struct perf_event *event)
3217
{
3218
	irq_work_sync(&event->pending);
3219

3220
	unaccount_event(event);
3221

3222
	if (event->rb) {
3223 3224 3225 3226 3227 3228 3229 3230 3231 3232 3233 3234 3235 3236 3237 3238
		struct ring_buffer *rb;

		/*
		 * 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);
		rb = event->rb;
		if (rb) {
			rcu_assign_pointer(event->rb, NULL);
			ring_buffer_detach(event, rb);
			ring_buffer_put(rb); /* could be last */
		}
		mutex_unlock(&event->mmap_mutex);
3239 3240
	}

S
Stephane Eranian 已提交
3241 3242 3243
	if (is_cgroup_event(event))
		perf_detach_cgroup(event);

P
Peter Zijlstra 已提交
3244

3245
	__free_event(event);
3246 3247
}

3248
int perf_event_release_kernel(struct perf_event *event)
T
Thomas Gleixner 已提交
3249
{
3250
	struct perf_event_context *ctx = event->ctx;
T
Thomas Gleixner 已提交
3251

3252
	WARN_ON_ONCE(ctx->parent_ctx);
3253 3254 3255 3256 3257 3258 3259 3260 3261 3262 3263 3264 3265
	/*
	 * There are two ways this annotation is useful:
	 *
	 *  1) there is a lock recursion from perf_event_exit_task
	 *     see the comment there.
	 *
	 *  2) there is a lock-inversion with mmap_sem through
	 *     perf_event_read_group(), which takes faults while
	 *     holding ctx->mutex, however this is called after
	 *     the last filedesc died, so there is no possibility
	 *     to trigger the AB-BA case.
	 */
	mutex_lock_nested(&ctx->mutex, SINGLE_DEPTH_NESTING);
3266
	raw_spin_lock_irq(&ctx->lock);
3267
	perf_group_detach(event);
3268
	raw_spin_unlock_irq(&ctx->lock);
3269
	perf_remove_from_context(event);
3270
	mutex_unlock(&ctx->mutex);
T
Thomas Gleixner 已提交
3271

3272
	free_event(event);
T
Thomas Gleixner 已提交
3273 3274 3275

	return 0;
}
3276
EXPORT_SYMBOL_GPL(perf_event_release_kernel);
T
Thomas Gleixner 已提交
3277

3278 3279 3280
/*
 * Called when the last reference to the file is gone.
 */
3281
static void put_event(struct perf_event *event)
3282
{
P
Peter Zijlstra 已提交
3283
	struct task_struct *owner;
3284

3285 3286
	if (!atomic_long_dec_and_test(&event->refcount))
		return;
3287

P
Peter Zijlstra 已提交
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
	rcu_read_lock();
	owner = ACCESS_ONCE(event->owner);
	/*
	 * Matches the smp_wmb() 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
	 * owner->perf_event_mutex.
	 */
	smp_read_barrier_depends();
	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) {
		mutex_lock(&owner->perf_event_mutex);
		/*
		 * 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.
		 */
		if (event->owner)
			list_del_init(&event->owner_entry);
		mutex_unlock(&owner->perf_event_mutex);
		put_task_struct(owner);
	}

3321 3322 3323 3324 3325 3326 3327
	perf_event_release_kernel(event);
}

static int perf_release(struct inode *inode, struct file *file)
{
	put_event(file->private_data);
	return 0;
3328 3329
}

3330
u64 perf_event_read_value(struct perf_event *event, u64 *enabled, u64 *running)
3331
{
3332
	struct perf_event *child;
3333 3334
	u64 total = 0;

3335 3336 3337
	*enabled = 0;
	*running = 0;

3338
	mutex_lock(&event->child_mutex);
3339
	total += perf_event_read(event);
3340 3341 3342 3343 3344 3345
	*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) {
3346
		total += perf_event_read(child);
3347 3348 3349
		*enabled += child->total_time_enabled;
		*running += child->total_time_running;
	}
3350
	mutex_unlock(&event->child_mutex);
3351 3352 3353

	return total;
}
3354
EXPORT_SYMBOL_GPL(perf_event_read_value);
3355

3356
static int perf_event_read_group(struct perf_event *event,
3357 3358
				   u64 read_format, char __user *buf)
{
3359
	struct perf_event *leader = event->group_leader, *sub;
3360 3361
	int n = 0, size = 0, ret = -EFAULT;
	struct perf_event_context *ctx = leader->ctx;
3362
	u64 values[5];
3363
	u64 count, enabled, running;
3364

3365
	mutex_lock(&ctx->mutex);
3366
	count = perf_event_read_value(leader, &enabled, &running);
3367 3368

	values[n++] = 1 + leader->nr_siblings;
3369 3370 3371 3372
	if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED)
		values[n++] = enabled;
	if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING)
		values[n++] = running;
3373 3374 3375
	values[n++] = count;
	if (read_format & PERF_FORMAT_ID)
		values[n++] = primary_event_id(leader);
3376 3377 3378 3379

	size = n * sizeof(u64);

	if (copy_to_user(buf, values, size))
3380
		goto unlock;
3381

3382
	ret = size;
3383

3384
	list_for_each_entry(sub, &leader->sibling_list, group_entry) {
3385
		n = 0;
3386

3387
		values[n++] = perf_event_read_value(sub, &enabled, &running);
3388 3389 3390 3391 3392
		if (read_format & PERF_FORMAT_ID)
			values[n++] = primary_event_id(sub);

		size = n * sizeof(u64);

3393
		if (copy_to_user(buf + ret, values, size)) {
3394 3395 3396
			ret = -EFAULT;
			goto unlock;
		}
3397 3398

		ret += size;
3399
	}
3400 3401
unlock:
	mutex_unlock(&ctx->mutex);
3402

3403
	return ret;
3404 3405
}

3406
static int perf_event_read_one(struct perf_event *event,
3407 3408
				 u64 read_format, char __user *buf)
{
3409
	u64 enabled, running;
3410 3411 3412
	u64 values[4];
	int n = 0;

3413 3414 3415 3416 3417
	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;
3418
	if (read_format & PERF_FORMAT_ID)
3419
		values[n++] = primary_event_id(event);
3420 3421 3422 3423 3424 3425 3426

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

	return n * sizeof(u64);
}

T
Thomas Gleixner 已提交
3427
/*
3428
 * Read the performance event - simple non blocking version for now
T
Thomas Gleixner 已提交
3429 3430
 */
static ssize_t
3431
perf_read_hw(struct perf_event *event, char __user *buf, size_t count)
T
Thomas Gleixner 已提交
3432
{
3433
	u64 read_format = event->attr.read_format;
3434
	int ret;
T
Thomas Gleixner 已提交
3435

3436
	/*
3437
	 * Return end-of-file for a read on a event that is in
3438 3439 3440
	 * error state (i.e. because it was pinned but it couldn't be
	 * scheduled on to the CPU at some point).
	 */
3441
	if (event->state == PERF_EVENT_STATE_ERROR)
3442 3443
		return 0;

3444
	if (count < event->read_size)
3445 3446
		return -ENOSPC;

3447
	WARN_ON_ONCE(event->ctx->parent_ctx);
3448
	if (read_format & PERF_FORMAT_GROUP)
3449
		ret = perf_event_read_group(event, read_format, buf);
3450
	else
3451
		ret = perf_event_read_one(event, read_format, buf);
T
Thomas Gleixner 已提交
3452

3453
	return ret;
T
Thomas Gleixner 已提交
3454 3455 3456 3457 3458
}

static ssize_t
perf_read(struct file *file, char __user *buf, size_t count, loff_t *ppos)
{
3459
	struct perf_event *event = file->private_data;
T
Thomas Gleixner 已提交
3460

3461
	return perf_read_hw(event, buf, count);
T
Thomas Gleixner 已提交
3462 3463 3464 3465
}

static unsigned int perf_poll(struct file *file, poll_table *wait)
{
3466
	struct perf_event *event = file->private_data;
3467
	struct ring_buffer *rb;
3468
	unsigned int events = POLL_HUP;
P
Peter Zijlstra 已提交
3469

3470
	/*
3471 3472
	 * Pin the event->rb by taking event->mmap_mutex; otherwise
	 * perf_event_set_output() can swizzle our rb and make us miss wakeups.
3473 3474
	 */
	mutex_lock(&event->mmap_mutex);
3475 3476
	rb = event->rb;
	if (rb)
3477
		events = atomic_xchg(&rb->poll, 0);
3478 3479
	mutex_unlock(&event->mmap_mutex);

3480
	poll_wait(file, &event->waitq, wait);
T
Thomas Gleixner 已提交
3481 3482 3483 3484

	return events;
}

3485
static void perf_event_reset(struct perf_event *event)
3486
{
3487
	(void)perf_event_read(event);
3488
	local64_set(&event->count, 0);
3489
	perf_event_update_userpage(event);
P
Peter Zijlstra 已提交
3490 3491
}

3492
/*
3493 3494 3495 3496
 * Holding the top-level event's child_mutex means that any
 * descendant process that has inherited this event will block
 * in sync_child_event if it goes to exit, thus satisfying the
 * task existence requirements of perf_event_enable/disable.
3497
 */
3498 3499
static void perf_event_for_each_child(struct perf_event *event,
					void (*func)(struct perf_event *))
P
Peter Zijlstra 已提交
3500
{
3501
	struct perf_event *child;
P
Peter Zijlstra 已提交
3502

3503 3504 3505 3506
	WARN_ON_ONCE(event->ctx->parent_ctx);
	mutex_lock(&event->child_mutex);
	func(event);
	list_for_each_entry(child, &event->child_list, child_list)
P
Peter Zijlstra 已提交
3507
		func(child);
3508
	mutex_unlock(&event->child_mutex);
P
Peter Zijlstra 已提交
3509 3510
}

3511 3512
static void perf_event_for_each(struct perf_event *event,
				  void (*func)(struct perf_event *))
P
Peter Zijlstra 已提交
3513
{
3514 3515
	struct perf_event_context *ctx = event->ctx;
	struct perf_event *sibling;
P
Peter Zijlstra 已提交
3516

3517 3518
	WARN_ON_ONCE(ctx->parent_ctx);
	mutex_lock(&ctx->mutex);
3519
	event = event->group_leader;
3520

3521 3522
	perf_event_for_each_child(event, func);
	list_for_each_entry(sibling, &event->sibling_list, group_entry)
3523
		perf_event_for_each_child(sibling, func);
3524
	mutex_unlock(&ctx->mutex);
3525 3526
}

3527
static int perf_event_period(struct perf_event *event, u64 __user *arg)
3528
{
3529
	struct perf_event_context *ctx = event->ctx;
3530 3531 3532
	int ret = 0;
	u64 value;

3533
	if (!is_sampling_event(event))
3534 3535
		return -EINVAL;

3536
	if (copy_from_user(&value, arg, sizeof(value)))
3537 3538 3539 3540 3541
		return -EFAULT;

	if (!value)
		return -EINVAL;

3542
	raw_spin_lock_irq(&ctx->lock);
3543 3544
	if (event->attr.freq) {
		if (value > sysctl_perf_event_sample_rate) {
3545 3546 3547 3548
			ret = -EINVAL;
			goto unlock;
		}

3549
		event->attr.sample_freq = value;
3550
	} else {
3551 3552
		event->attr.sample_period = value;
		event->hw.sample_period = value;
3553 3554
	}
unlock:
3555
	raw_spin_unlock_irq(&ctx->lock);
3556 3557 3558 3559

	return ret;
}

3560 3561
static const struct file_operations perf_fops;

3562
static inline int perf_fget_light(int fd, struct fd *p)
3563
{
3564 3565 3566
	struct fd f = fdget(fd);
	if (!f.file)
		return -EBADF;
3567

3568 3569 3570
	if (f.file->f_op != &perf_fops) {
		fdput(f);
		return -EBADF;
3571
	}
3572 3573
	*p = f;
	return 0;
3574 3575 3576 3577
}

static int perf_event_set_output(struct perf_event *event,
				 struct perf_event *output_event);
L
Li Zefan 已提交
3578
static int perf_event_set_filter(struct perf_event *event, void __user *arg);
3579

3580 3581
static long perf_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
{
3582 3583
	struct perf_event *event = file->private_data;
	void (*func)(struct perf_event *);
P
Peter Zijlstra 已提交
3584
	u32 flags = arg;
3585 3586

	switch (cmd) {
3587 3588
	case PERF_EVENT_IOC_ENABLE:
		func = perf_event_enable;
3589
		break;
3590 3591
	case PERF_EVENT_IOC_DISABLE:
		func = perf_event_disable;
3592
		break;
3593 3594
	case PERF_EVENT_IOC_RESET:
		func = perf_event_reset;
3595
		break;
P
Peter Zijlstra 已提交
3596

3597 3598
	case PERF_EVENT_IOC_REFRESH:
		return perf_event_refresh(event, arg);
3599

3600 3601
	case PERF_EVENT_IOC_PERIOD:
		return perf_event_period(event, (u64 __user *)arg);
3602

3603 3604 3605 3606 3607 3608 3609 3610 3611
	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;
	}

3612
	case PERF_EVENT_IOC_SET_OUTPUT:
3613 3614 3615
	{
		int ret;
		if (arg != -1) {
3616 3617 3618 3619 3620 3621 3622 3623 3624 3625
			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);
3626 3627 3628
		}
		return ret;
	}
3629

L
Li Zefan 已提交
3630 3631 3632
	case PERF_EVENT_IOC_SET_FILTER:
		return perf_event_set_filter(event, (void __user *)arg);

3633
	default:
P
Peter Zijlstra 已提交
3634
		return -ENOTTY;
3635
	}
P
Peter Zijlstra 已提交
3636 3637

	if (flags & PERF_IOC_FLAG_GROUP)
3638
		perf_event_for_each(event, func);
P
Peter Zijlstra 已提交
3639
	else
3640
		perf_event_for_each_child(event, func);
P
Peter Zijlstra 已提交
3641 3642

	return 0;
3643 3644
}

3645
int perf_event_task_enable(void)
3646
{
3647
	struct perf_event *event;
3648

3649 3650 3651 3652
	mutex_lock(&current->perf_event_mutex);
	list_for_each_entry(event, &current->perf_event_list, owner_entry)
		perf_event_for_each_child(event, perf_event_enable);
	mutex_unlock(&current->perf_event_mutex);
3653 3654 3655 3656

	return 0;
}

3657
int perf_event_task_disable(void)
3658
{
3659
	struct perf_event *event;
3660

3661 3662 3663 3664
	mutex_lock(&current->perf_event_mutex);
	list_for_each_entry(event, &current->perf_event_list, owner_entry)
		perf_event_for_each_child(event, perf_event_disable);
	mutex_unlock(&current->perf_event_mutex);
3665 3666 3667 3668

	return 0;
}

3669
static int perf_event_index(struct perf_event *event)
3670
{
P
Peter Zijlstra 已提交
3671 3672 3673
	if (event->hw.state & PERF_HES_STOPPED)
		return 0;

3674
	if (event->state != PERF_EVENT_STATE_ACTIVE)
3675 3676
		return 0;

3677
	return event->pmu->event_idx(event);
3678 3679
}

3680
static void calc_timer_values(struct perf_event *event,
3681
				u64 *now,
3682 3683
				u64 *enabled,
				u64 *running)
3684
{
3685
	u64 ctx_time;
3686

3687 3688
	*now = perf_clock();
	ctx_time = event->shadow_ctx_time + *now;
3689 3690 3691 3692
	*enabled = ctx_time - event->tstamp_enabled;
	*running = ctx_time - event->tstamp_running;
}

3693 3694 3695 3696 3697 3698 3699 3700 3701 3702 3703 3704 3705 3706 3707 3708 3709 3710 3711 3712
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);

unlock:
	rcu_read_unlock();
}

3713
void __weak arch_perf_update_userpage(struct perf_event_mmap_page *userpg, u64 now)
3714 3715 3716
{
}

3717 3718 3719 3720 3721
/*
 * 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.
 */
3722
void perf_event_update_userpage(struct perf_event *event)
3723
{
3724
	struct perf_event_mmap_page *userpg;
3725
	struct ring_buffer *rb;
3726
	u64 enabled, running, now;
3727 3728

	rcu_read_lock();
3729 3730 3731 3732
	rb = rcu_dereference(event->rb);
	if (!rb)
		goto unlock;

3733 3734 3735 3736 3737 3738 3739 3740 3741
	/*
	 * 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
	 */
3742
	calc_timer_values(event, &now, &enabled, &running);
3743

3744
	userpg = rb->user_page;
3745 3746 3747 3748 3749
	/*
	 * Disable preemption so as to not let the corresponding user-space
	 * spin too long if we get preempted.
	 */
	preempt_disable();
3750
	++userpg->lock;
3751
	barrier();
3752
	userpg->index = perf_event_index(event);
P
Peter Zijlstra 已提交
3753
	userpg->offset = perf_event_count(event);
3754
	if (userpg->index)
3755
		userpg->offset -= local64_read(&event->hw.prev_count);
3756

3757
	userpg->time_enabled = enabled +
3758
			atomic64_read(&event->child_total_time_enabled);
3759

3760
	userpg->time_running = running +
3761
			atomic64_read(&event->child_total_time_running);
3762

3763
	arch_perf_update_userpage(userpg, now);
3764

3765
	barrier();
3766
	++userpg->lock;
3767
	preempt_enable();
3768
unlock:
3769
	rcu_read_unlock();
3770 3771
}

3772 3773 3774
static int perf_mmap_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
{
	struct perf_event *event = vma->vm_file->private_data;
3775
	struct ring_buffer *rb;
3776 3777 3778 3779 3780 3781 3782 3783 3784
	int ret = VM_FAULT_SIGBUS;

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

	rcu_read_lock();
3785 3786
	rb = rcu_dereference(event->rb);
	if (!rb)
3787 3788 3789 3790 3791
		goto unlock;

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

3792
	vmf->page = perf_mmap_to_page(rb, vmf->pgoff);
3793 3794 3795 3796 3797 3798 3799 3800 3801 3802 3803 3804 3805 3806
	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;
}

3807 3808 3809 3810 3811 3812 3813 3814 3815
static void ring_buffer_attach(struct perf_event *event,
			       struct ring_buffer *rb)
{
	unsigned long flags;

	if (!list_empty(&event->rb_entry))
		return;

	spin_lock_irqsave(&rb->event_lock, flags);
3816 3817
	if (list_empty(&event->rb_entry))
		list_add(&event->rb_entry, &rb->event_list);
3818 3819 3820
	spin_unlock_irqrestore(&rb->event_lock, flags);
}

3821
static void ring_buffer_detach(struct perf_event *event, struct ring_buffer *rb)
3822 3823 3824 3825 3826 3827 3828 3829 3830 3831 3832 3833 3834 3835 3836 3837 3838 3839
{
	unsigned long flags;

	if (list_empty(&event->rb_entry))
		return;

	spin_lock_irqsave(&rb->event_lock, flags);
	list_del_init(&event->rb_entry);
	wake_up_all(&event->waitq);
	spin_unlock_irqrestore(&rb->event_lock, flags);
}

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

	rcu_read_lock();
	rb = rcu_dereference(event->rb);
3840 3841 3842 3843
	if (rb) {
		list_for_each_entry_rcu(event, &rb->event_list, rb_entry)
			wake_up_all(&event->waitq);
	}
3844 3845 3846
	rcu_read_unlock();
}

3847
static void rb_free_rcu(struct rcu_head *rcu_head)
3848
{
3849
	struct ring_buffer *rb;
3850

3851 3852
	rb = container_of(rcu_head, struct ring_buffer, rcu_head);
	rb_free(rb);
3853 3854
}

3855
static struct ring_buffer *ring_buffer_get(struct perf_event *event)
3856
{
3857
	struct ring_buffer *rb;
3858

3859
	rcu_read_lock();
3860 3861 3862 3863
	rb = rcu_dereference(event->rb);
	if (rb) {
		if (!atomic_inc_not_zero(&rb->refcount))
			rb = NULL;
3864 3865 3866
	}
	rcu_read_unlock();

3867
	return rb;
3868 3869
}

3870
static void ring_buffer_put(struct ring_buffer *rb)
3871
{
3872
	if (!atomic_dec_and_test(&rb->refcount))
3873
		return;
3874

3875
	WARN_ON_ONCE(!list_empty(&rb->event_list));
3876

3877
	call_rcu(&rb->rcu_head, rb_free_rcu);
3878 3879 3880 3881
}

static void perf_mmap_open(struct vm_area_struct *vma)
{
3882
	struct perf_event *event = vma->vm_file->private_data;
3883

3884
	atomic_inc(&event->mmap_count);
3885
	atomic_inc(&event->rb->mmap_count);
3886 3887
}

3888 3889 3890 3891 3892 3893 3894 3895
/*
 * 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.
 */
3896 3897
static void perf_mmap_close(struct vm_area_struct *vma)
{
3898
	struct perf_event *event = vma->vm_file->private_data;
3899

3900 3901 3902 3903
	struct ring_buffer *rb = event->rb;
	struct user_struct *mmap_user = rb->mmap_user;
	int mmap_locked = rb->mmap_locked;
	unsigned long size = perf_data_size(rb);
3904

3905 3906 3907 3908 3909 3910 3911 3912 3913 3914 3915 3916 3917 3918 3919
	atomic_dec(&rb->mmap_count);

	if (!atomic_dec_and_mutex_lock(&event->mmap_count, &event->mmap_mutex))
		return;

	/* Detach current event from the buffer. */
	rcu_assign_pointer(event->rb, NULL);
	ring_buffer_detach(event, rb);
	mutex_unlock(&event->mmap_mutex);

	/* If there's still other mmap()s of this buffer, we're done. */
	if (atomic_read(&rb->mmap_count)) {
		ring_buffer_put(rb); /* can't be last */
		return;
	}
3920

3921 3922 3923 3924 3925 3926 3927 3928 3929 3930 3931 3932 3933 3934 3935 3936
	/*
	 * 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();
3937

3938 3939 3940 3941 3942 3943 3944 3945 3946 3947 3948 3949 3950 3951 3952
		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.
		 */
		if (event->rb == rb) {
			rcu_assign_pointer(event->rb, NULL);
			ring_buffer_detach(event, rb);
			ring_buffer_put(rb); /* can't be last, we still have one */
P
Peter Zijlstra 已提交
3953
		}
3954
		mutex_unlock(&event->mmap_mutex);
3955
		put_event(event);
3956

3957 3958 3959 3960 3961
		/*
		 * Restart the iteration; either we're on the wrong list or
		 * destroyed its integrity by doing a deletion.
		 */
		goto again;
3962
	}
3963 3964 3965 3966 3967 3968 3969 3970 3971 3972 3973 3974 3975 3976 3977 3978
	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);

	ring_buffer_put(rb); /* could be last */
3979 3980
}

3981
static const struct vm_operations_struct perf_mmap_vmops = {
3982 3983 3984 3985
	.open		= perf_mmap_open,
	.close		= perf_mmap_close,
	.fault		= perf_mmap_fault,
	.page_mkwrite	= perf_mmap_fault,
3986 3987 3988 3989
};

static int perf_mmap(struct file *file, struct vm_area_struct *vma)
{
3990
	struct perf_event *event = file->private_data;
3991
	unsigned long user_locked, user_lock_limit;
3992
	struct user_struct *user = current_user();
3993
	unsigned long locked, lock_limit;
3994
	struct ring_buffer *rb;
3995 3996
	unsigned long vma_size;
	unsigned long nr_pages;
3997
	long user_extra, extra;
3998
	int ret = 0, flags = 0;
3999

4000 4001 4002
	/*
	 * Don't allow mmap() of inherited per-task counters. This would
	 * create a performance issue due to all children writing to the
4003
	 * same rb.
4004 4005 4006 4007
	 */
	if (event->cpu == -1 && event->attr.inherit)
		return -EINVAL;

4008
	if (!(vma->vm_flags & VM_SHARED))
4009
		return -EINVAL;
4010 4011 4012 4013

	vma_size = vma->vm_end - vma->vm_start;
	nr_pages = (vma_size / PAGE_SIZE) - 1;

4014
	/*
4015
	 * If we have rb pages ensure they're a power-of-two number, so we
4016 4017 4018
	 * can do bitmasks instead of modulo.
	 */
	if (nr_pages != 0 && !is_power_of_2(nr_pages))
4019 4020
		return -EINVAL;

4021
	if (vma_size != PAGE_SIZE * (1 + nr_pages))
4022 4023
		return -EINVAL;

4024 4025
	if (vma->vm_pgoff != 0)
		return -EINVAL;
4026

4027
	WARN_ON_ONCE(event->ctx->parent_ctx);
4028
again:
4029
	mutex_lock(&event->mmap_mutex);
4030
	if (event->rb) {
4031
		if (event->rb->nr_pages != nr_pages) {
4032
			ret = -EINVAL;
4033 4034 4035 4036 4037 4038 4039 4040 4041 4042 4043 4044 4045
			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;
		}

4046 4047 4048
		goto unlock;
	}

4049
	user_extra = nr_pages + 1;
4050
	user_lock_limit = sysctl_perf_event_mlock >> (PAGE_SHIFT - 10);
I
Ingo Molnar 已提交
4051 4052 4053 4054 4055 4056

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

4057
	user_locked = atomic_long_read(&user->locked_vm) + user_extra;
4058

4059 4060 4061
	extra = 0;
	if (user_locked > user_lock_limit)
		extra = user_locked - user_lock_limit;
4062

4063
	lock_limit = rlimit(RLIMIT_MEMLOCK);
4064
	lock_limit >>= PAGE_SHIFT;
4065
	locked = vma->vm_mm->pinned_vm + extra;
4066

4067 4068
	if ((locked > lock_limit) && perf_paranoid_tracepoint_raw() &&
		!capable(CAP_IPC_LOCK)) {
4069 4070 4071
		ret = -EPERM;
		goto unlock;
	}
4072

4073
	WARN_ON(event->rb);
4074

4075
	if (vma->vm_flags & VM_WRITE)
4076
		flags |= RING_BUFFER_WRITABLE;
4077

4078 4079 4080 4081
	rb = rb_alloc(nr_pages, 
		event->attr.watermark ? event->attr.wakeup_watermark : 0,
		event->cpu, flags);

4082
	if (!rb) {
4083
		ret = -ENOMEM;
4084
		goto unlock;
4085
	}
P
Peter Zijlstra 已提交
4086

4087
	atomic_set(&rb->mmap_count, 1);
P
Peter Zijlstra 已提交
4088 4089
	rb->mmap_locked = extra;
	rb->mmap_user = get_current_user();
4090

4091
	atomic_long_add(user_extra, &user->locked_vm);
P
Peter Zijlstra 已提交
4092 4093
	vma->vm_mm->pinned_vm += extra;

4094
	ring_buffer_attach(event, rb);
P
Peter Zijlstra 已提交
4095
	rcu_assign_pointer(event->rb, rb);
4096

4097
	perf_event_init_userpage(event);
4098 4099
	perf_event_update_userpage(event);

4100
unlock:
4101 4102
	if (!ret)
		atomic_inc(&event->mmap_count);
4103
	mutex_unlock(&event->mmap_mutex);
4104

4105 4106 4107 4108
	/*
	 * Since pinned accounting is per vm we cannot allow fork() to copy our
	 * vma.
	 */
P
Peter Zijlstra 已提交
4109
	vma->vm_flags |= VM_DONTCOPY | VM_DONTEXPAND | VM_DONTDUMP;
4110
	vma->vm_ops = &perf_mmap_vmops;
4111 4112

	return ret;
4113 4114
}

P
Peter Zijlstra 已提交
4115 4116
static int perf_fasync(int fd, struct file *filp, int on)
{
A
Al Viro 已提交
4117
	struct inode *inode = file_inode(filp);
4118
	struct perf_event *event = filp->private_data;
P
Peter Zijlstra 已提交
4119 4120 4121
	int retval;

	mutex_lock(&inode->i_mutex);
4122
	retval = fasync_helper(fd, filp, on, &event->fasync);
P
Peter Zijlstra 已提交
4123 4124 4125 4126 4127 4128 4129 4130
	mutex_unlock(&inode->i_mutex);

	if (retval < 0)
		return retval;

	return 0;
}

T
Thomas Gleixner 已提交
4131
static const struct file_operations perf_fops = {
4132
	.llseek			= no_llseek,
T
Thomas Gleixner 已提交
4133 4134 4135
	.release		= perf_release,
	.read			= perf_read,
	.poll			= perf_poll,
4136 4137
	.unlocked_ioctl		= perf_ioctl,
	.compat_ioctl		= perf_ioctl,
4138
	.mmap			= perf_mmap,
P
Peter Zijlstra 已提交
4139
	.fasync			= perf_fasync,
T
Thomas Gleixner 已提交
4140 4141
};

4142
/*
4143
 * Perf event wakeup
4144 4145 4146 4147 4148
 *
 * If there's data, ensure we set the poll() state and publish everything
 * to user-space before waking everybody up.
 */

4149
void perf_event_wakeup(struct perf_event *event)
4150
{
4151
	ring_buffer_wakeup(event);
4152

4153 4154 4155
	if (event->pending_kill) {
		kill_fasync(&event->fasync, SIGIO, event->pending_kill);
		event->pending_kill = 0;
4156
	}
4157 4158
}

4159
static void perf_pending_event(struct irq_work *entry)
4160
{
4161 4162
	struct perf_event *event = container_of(entry,
			struct perf_event, pending);
4163

4164 4165 4166
	if (event->pending_disable) {
		event->pending_disable = 0;
		__perf_event_disable(event);
4167 4168
	}

4169 4170 4171
	if (event->pending_wakeup) {
		event->pending_wakeup = 0;
		perf_event_wakeup(event);
4172 4173 4174
	}
}

4175 4176 4177 4178 4179 4180 4181 4182 4183 4184 4185 4186 4187 4188 4189 4190 4191 4192 4193 4194 4195
/*
 * 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);

4196 4197 4198 4199 4200 4201 4202 4203 4204 4205 4206 4207 4208 4209 4210 4211 4212 4213 4214 4215 4216 4217 4218 4219 4220 4221 4222 4223 4224 4225 4226
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);
	}
}

static void perf_sample_regs_user(struct perf_regs_user *regs_user,
				  struct pt_regs *regs)
{
	if (!user_mode(regs)) {
		if (current->mm)
			regs = task_pt_regs(current);
		else
			regs = NULL;
	}

	if (regs) {
		regs_user->regs = regs;
		regs_user->abi  = perf_reg_abi(current);
	}
}

4227 4228 4229 4230 4231 4232 4233 4234 4235 4236 4237 4238 4239 4240 4241 4242 4243 4244 4245 4246 4247 4248 4249 4250 4251 4252 4253 4254 4255 4256 4257 4258 4259 4260 4261 4262 4263 4264 4265 4266 4267 4268 4269 4270 4271 4272 4273 4274 4275 4276 4277 4278 4279 4280 4281 4282 4283 4284 4285 4286 4287 4288 4289 4290 4291 4292 4293 4294 4295 4296 4297 4298 4299 4300 4301 4302 4303 4304 4305 4306 4307 4308 4309 4310 4311 4312 4313 4314 4315 4316 4317 4318 4319 4320 4321
/*
 * 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);
	}
}

4322 4323 4324
static void __perf_event_header__init_id(struct perf_event_header *header,
					 struct perf_sample_data *data,
					 struct perf_event *event)
4325 4326 4327 4328 4329 4330 4331 4332 4333 4334 4335 4336 4337 4338 4339
{
	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)
		data->time = perf_clock();

4340
	if (sample_type & (PERF_SAMPLE_ID | PERF_SAMPLE_IDENTIFIER))
4341 4342 4343 4344 4345 4346 4347 4348 4349 4350 4351
		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;
	}
}

4352 4353 4354
void perf_event_header__init_id(struct perf_event_header *header,
				struct perf_sample_data *data,
				struct perf_event *event)
4355 4356 4357 4358 4359 4360 4361 4362 4363 4364 4365 4366 4367 4368 4369 4370 4371 4372 4373 4374 4375 4376 4377 4378
{
	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);
4379 4380 4381

	if (sample_type & PERF_SAMPLE_IDENTIFIER)
		perf_output_put(handle, data->id);
4382 4383
}

4384 4385 4386
void perf_event__output_id_sample(struct perf_event *event,
				  struct perf_output_handle *handle,
				  struct perf_sample_data *sample)
4387 4388 4389 4390 4391
{
	if (event->attr.sample_id_all)
		__perf_event__output_id_sample(handle, sample);
}

4392
static void perf_output_read_one(struct perf_output_handle *handle,
4393 4394
				 struct perf_event *event,
				 u64 enabled, u64 running)
4395
{
4396
	u64 read_format = event->attr.read_format;
4397 4398 4399
	u64 values[4];
	int n = 0;

P
Peter Zijlstra 已提交
4400
	values[n++] = perf_event_count(event);
4401
	if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED) {
4402
		values[n++] = enabled +
4403
			atomic64_read(&event->child_total_time_enabled);
4404 4405
	}
	if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING) {
4406
		values[n++] = running +
4407
			atomic64_read(&event->child_total_time_running);
4408 4409
	}
	if (read_format & PERF_FORMAT_ID)
4410
		values[n++] = primary_event_id(event);
4411

4412
	__output_copy(handle, values, n * sizeof(u64));
4413 4414 4415
}

/*
4416
 * XXX PERF_FORMAT_GROUP vs inherited events seems difficult.
4417 4418
 */
static void perf_output_read_group(struct perf_output_handle *handle,
4419 4420
			    struct perf_event *event,
			    u64 enabled, u64 running)
4421
{
4422 4423
	struct perf_event *leader = event->group_leader, *sub;
	u64 read_format = event->attr.read_format;
4424 4425 4426 4427 4428 4429
	u64 values[5];
	int n = 0;

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

	if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED)
4430
		values[n++] = enabled;
4431 4432

	if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING)
4433
		values[n++] = running;
4434

4435
	if (leader != event)
4436 4437
		leader->pmu->read(leader);

P
Peter Zijlstra 已提交
4438
	values[n++] = perf_event_count(leader);
4439
	if (read_format & PERF_FORMAT_ID)
4440
		values[n++] = primary_event_id(leader);
4441

4442
	__output_copy(handle, values, n * sizeof(u64));
4443

4444
	list_for_each_entry(sub, &leader->sibling_list, group_entry) {
4445 4446
		n = 0;

4447 4448
		if ((sub != event) &&
		    (sub->state == PERF_EVENT_STATE_ACTIVE))
4449 4450
			sub->pmu->read(sub);

P
Peter Zijlstra 已提交
4451
		values[n++] = perf_event_count(sub);
4452
		if (read_format & PERF_FORMAT_ID)
4453
			values[n++] = primary_event_id(sub);
4454

4455
		__output_copy(handle, values, n * sizeof(u64));
4456 4457 4458
	}
}

4459 4460 4461
#define PERF_FORMAT_TOTAL_TIMES (PERF_FORMAT_TOTAL_TIME_ENABLED|\
				 PERF_FORMAT_TOTAL_TIME_RUNNING)

4462
static void perf_output_read(struct perf_output_handle *handle,
4463
			     struct perf_event *event)
4464
{
4465
	u64 enabled = 0, running = 0, now;
4466 4467 4468 4469 4470 4471 4472 4473 4474 4475 4476
	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
	 */
4477
	if (read_format & PERF_FORMAT_TOTAL_TIMES)
4478
		calc_timer_values(event, &now, &enabled, &running);
4479

4480
	if (event->attr.read_format & PERF_FORMAT_GROUP)
4481
		perf_output_read_group(handle, event, enabled, running);
4482
	else
4483
		perf_output_read_one(handle, event, enabled, running);
4484 4485
}

4486 4487 4488
void perf_output_sample(struct perf_output_handle *handle,
			struct perf_event_header *header,
			struct perf_sample_data *data,
4489
			struct perf_event *event)
4490 4491 4492 4493 4494
{
	u64 sample_type = data->type;

	perf_output_put(handle, *header);

4495 4496 4497
	if (sample_type & PERF_SAMPLE_IDENTIFIER)
		perf_output_put(handle, data->id);

4498 4499 4500 4501 4502 4503 4504 4505 4506 4507 4508 4509 4510 4511 4512 4513 4514 4515 4516 4517 4518 4519 4520 4521 4522
	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)
4523
		perf_output_read(handle, event);
4524 4525 4526 4527 4528 4529 4530 4531 4532 4533

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

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

			size *= sizeof(u64);

4534
			__output_copy(handle, data->callchain, size);
4535 4536 4537 4538 4539 4540 4541 4542 4543
		} else {
			u64 nr = 0;
			perf_output_put(handle, nr);
		}
	}

	if (sample_type & PERF_SAMPLE_RAW) {
		if (data->raw) {
			perf_output_put(handle, data->raw->size);
4544 4545
			__output_copy(handle, data->raw->data,
					   data->raw->size);
4546 4547 4548 4549 4550 4551 4552 4553 4554 4555 4556
		} else {
			struct {
				u32	size;
				u32	data;
			} raw = {
				.size = sizeof(u32),
				.data = 0,
			};
			perf_output_put(handle, raw);
		}
	}
4557

4558 4559 4560 4561 4562 4563 4564 4565 4566 4567 4568 4569 4570 4571 4572 4573 4574
	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);
		}
	}
4575 4576 4577 4578 4579 4580 4581 4582 4583 4584 4585 4586 4587 4588 4589 4590 4591

	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);
		}
	}
4592

4593
	if (sample_type & PERF_SAMPLE_STACK_USER) {
4594 4595 4596
		perf_output_sample_ustack(handle,
					  data->stack_user_size,
					  data->regs_user.regs);
4597
	}
A
Andi Kleen 已提交
4598 4599 4600

	if (sample_type & PERF_SAMPLE_WEIGHT)
		perf_output_put(handle, data->weight);
4601 4602 4603

	if (sample_type & PERF_SAMPLE_DATA_SRC)
		perf_output_put(handle, data->data_src.val);
4604

A
Andi Kleen 已提交
4605 4606 4607
	if (sample_type & PERF_SAMPLE_TRANSACTION)
		perf_output_put(handle, data->txn);

4608 4609 4610 4611 4612 4613 4614 4615 4616 4617 4618 4619 4620
	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);
			}
		}
	}
4621 4622 4623 4624
}

void perf_prepare_sample(struct perf_event_header *header,
			 struct perf_sample_data *data,
4625
			 struct perf_event *event,
4626
			 struct pt_regs *regs)
4627
{
4628
	u64 sample_type = event->attr.sample_type;
4629

4630
	header->type = PERF_RECORD_SAMPLE;
4631
	header->size = sizeof(*header) + event->header_size;
4632 4633 4634

	header->misc = 0;
	header->misc |= perf_misc_flags(regs);
4635

4636
	__perf_event_header__init_id(header, data, event);
4637

4638
	if (sample_type & PERF_SAMPLE_IP)
4639 4640
		data->ip = perf_instruction_pointer(regs);

4641
	if (sample_type & PERF_SAMPLE_CALLCHAIN) {
4642
		int size = 1;
4643

4644
		data->callchain = perf_callchain(event, regs);
4645 4646 4647 4648 4649

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

		header->size += size * sizeof(u64);
4650 4651
	}

4652
	if (sample_type & PERF_SAMPLE_RAW) {
4653 4654 4655 4656 4657 4658 4659 4660
		int size = sizeof(u32);

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

		WARN_ON_ONCE(size & (sizeof(u64)-1));
4661
		header->size += size;
4662
	}
4663 4664 4665 4666 4667 4668 4669 4670 4671

	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;
	}
4672 4673 4674 4675 4676 4677 4678 4679 4680 4681 4682 4683 4684 4685

	if (sample_type & PERF_SAMPLE_REGS_USER) {
		/* regs dump ABI info */
		int size = sizeof(u64);

		perf_sample_regs_user(&data->regs_user, regs);

		if (data->regs_user.regs) {
			u64 mask = event->attr.sample_regs_user;
			size += hweight64(mask) * sizeof(u64);
		}

		header->size += size;
	}
4686 4687 4688 4689 4690 4691 4692 4693 4694 4695 4696 4697 4698 4699 4700 4701 4702 4703 4704 4705 4706 4707 4708 4709 4710 4711 4712 4713 4714

	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.
		 */
		struct perf_regs_user *uregs = &data->regs_user;
		u16 stack_size = event->attr.sample_stack_user;
		u16 size = sizeof(u64);

		if (!uregs->abi)
			perf_sample_regs_user(uregs, regs);

		stack_size = perf_sample_ustack_size(stack_size, header->size,
						     uregs->regs);

		/*
		 * 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;
	}
4715
}
4716

4717
static void perf_event_output(struct perf_event *event,
4718 4719 4720 4721 4722
				struct perf_sample_data *data,
				struct pt_regs *regs)
{
	struct perf_output_handle handle;
	struct perf_event_header header;
4723

4724 4725 4726
	/* protect the callchain buffers */
	rcu_read_lock();

4727
	perf_prepare_sample(&header, data, event, regs);
P
Peter Zijlstra 已提交
4728

4729
	if (perf_output_begin(&handle, event, header.size))
4730
		goto exit;
4731

4732
	perf_output_sample(&handle, &header, data, event);
4733

4734
	perf_output_end(&handle);
4735 4736 4737

exit:
	rcu_read_unlock();
4738 4739
}

4740
/*
4741
 * read event_id
4742 4743 4744 4745 4746 4747 4748 4749 4750 4751
 */

struct perf_read_event {
	struct perf_event_header	header;

	u32				pid;
	u32				tid;
};

static void
4752
perf_event_read_event(struct perf_event *event,
4753 4754 4755
			struct task_struct *task)
{
	struct perf_output_handle handle;
4756
	struct perf_sample_data sample;
4757
	struct perf_read_event read_event = {
4758
		.header = {
4759
			.type = PERF_RECORD_READ,
4760
			.misc = 0,
4761
			.size = sizeof(read_event) + event->read_size,
4762
		},
4763 4764
		.pid = perf_event_pid(event, task),
		.tid = perf_event_tid(event, task),
4765
	};
4766
	int ret;
4767

4768
	perf_event_header__init_id(&read_event.header, &sample, event);
4769
	ret = perf_output_begin(&handle, event, read_event.header.size);
4770 4771 4772
	if (ret)
		return;

4773
	perf_output_put(&handle, read_event);
4774
	perf_output_read(&handle, event);
4775
	perf_event__output_id_sample(event, &handle, &sample);
4776

4777 4778 4779
	perf_output_end(&handle);
}

4780 4781 4782 4783 4784 4785 4786 4787 4788 4789 4790 4791 4792 4793
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;
4794
		output(event, data);
4795 4796 4797 4798
	}
}

static void
4799
perf_event_aux(perf_event_aux_output_cb output, void *data,
4800 4801 4802 4803 4804 4805 4806 4807 4808 4809 4810 4811
	       struct perf_event_context *task_ctx)
{
	struct perf_cpu_context *cpuctx;
	struct perf_event_context *ctx;
	struct pmu *pmu;
	int ctxn;

	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;
4812
		perf_event_aux_ctx(&cpuctx->ctx, output, data);
4813 4814 4815 4816 4817 4818 4819
		if (task_ctx)
			goto next;
		ctxn = pmu->task_ctx_nr;
		if (ctxn < 0)
			goto next;
		ctx = rcu_dereference(current->perf_event_ctxp[ctxn]);
		if (ctx)
4820
			perf_event_aux_ctx(ctx, output, data);
4821 4822 4823 4824 4825 4826
next:
		put_cpu_ptr(pmu->pmu_cpu_context);
	}

	if (task_ctx) {
		preempt_disable();
4827
		perf_event_aux_ctx(task_ctx, output, data);
4828 4829 4830 4831 4832
		preempt_enable();
	}
	rcu_read_unlock();
}

P
Peter Zijlstra 已提交
4833
/*
P
Peter Zijlstra 已提交
4834 4835
 * task tracking -- fork/exit
 *
4836
 * enabled by: attr.comm | attr.mmap | attr.mmap2 | attr.mmap_data | attr.task
P
Peter Zijlstra 已提交
4837 4838
 */

P
Peter Zijlstra 已提交
4839
struct perf_task_event {
4840
	struct task_struct		*task;
4841
	struct perf_event_context	*task_ctx;
P
Peter Zijlstra 已提交
4842 4843 4844 4845 4846 4847

	struct {
		struct perf_event_header	header;

		u32				pid;
		u32				ppid;
P
Peter Zijlstra 已提交
4848 4849
		u32				tid;
		u32				ptid;
4850
		u64				time;
4851
	} event_id;
P
Peter Zijlstra 已提交
4852 4853
};

4854 4855
static int perf_event_task_match(struct perf_event *event)
{
4856 4857 4858
	return event->attr.comm  || event->attr.mmap ||
	       event->attr.mmap2 || event->attr.mmap_data ||
	       event->attr.task;
4859 4860
}

4861
static void perf_event_task_output(struct perf_event *event,
4862
				   void *data)
P
Peter Zijlstra 已提交
4863
{
4864
	struct perf_task_event *task_event = data;
P
Peter Zijlstra 已提交
4865
	struct perf_output_handle handle;
4866
	struct perf_sample_data	sample;
P
Peter Zijlstra 已提交
4867
	struct task_struct *task = task_event->task;
4868
	int ret, size = task_event->event_id.header.size;
4869

4870 4871 4872
	if (!perf_event_task_match(event))
		return;

4873
	perf_event_header__init_id(&task_event->event_id.header, &sample, event);
P
Peter Zijlstra 已提交
4874

4875
	ret = perf_output_begin(&handle, event,
4876
				task_event->event_id.header.size);
4877
	if (ret)
4878
		goto out;
P
Peter Zijlstra 已提交
4879

4880 4881
	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
4882

4883 4884
	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
4885

4886
	perf_output_put(&handle, task_event->event_id);
4887

4888 4889
	perf_event__output_id_sample(event, &handle, &sample);

P
Peter Zijlstra 已提交
4890
	perf_output_end(&handle);
4891 4892
out:
	task_event->event_id.header.size = size;
P
Peter Zijlstra 已提交
4893 4894
}

4895 4896
static void perf_event_task(struct task_struct *task,
			      struct perf_event_context *task_ctx,
4897
			      int new)
P
Peter Zijlstra 已提交
4898
{
P
Peter Zijlstra 已提交
4899
	struct perf_task_event task_event;
P
Peter Zijlstra 已提交
4900

4901 4902 4903
	if (!atomic_read(&nr_comm_events) &&
	    !atomic_read(&nr_mmap_events) &&
	    !atomic_read(&nr_task_events))
P
Peter Zijlstra 已提交
4904 4905
		return;

P
Peter Zijlstra 已提交
4906
	task_event = (struct perf_task_event){
4907 4908
		.task	  = task,
		.task_ctx = task_ctx,
4909
		.event_id    = {
P
Peter Zijlstra 已提交
4910
			.header = {
4911
				.type = new ? PERF_RECORD_FORK : PERF_RECORD_EXIT,
4912
				.misc = 0,
4913
				.size = sizeof(task_event.event_id),
P
Peter Zijlstra 已提交
4914
			},
4915 4916
			/* .pid  */
			/* .ppid */
P
Peter Zijlstra 已提交
4917 4918
			/* .tid  */
			/* .ptid */
P
Peter Zijlstra 已提交
4919
			.time = perf_clock(),
P
Peter Zijlstra 已提交
4920 4921 4922
		},
	};

4923
	perf_event_aux(perf_event_task_output,
4924 4925
		       &task_event,
		       task_ctx);
P
Peter Zijlstra 已提交
4926 4927
}

4928
void perf_event_fork(struct task_struct *task)
P
Peter Zijlstra 已提交
4929
{
4930
	perf_event_task(task, NULL, 1);
P
Peter Zijlstra 已提交
4931 4932
}

4933 4934 4935 4936 4937
/*
 * comm tracking
 */

struct perf_comm_event {
4938 4939
	struct task_struct	*task;
	char			*comm;
4940 4941 4942 4943 4944 4945 4946
	int			comm_size;

	struct {
		struct perf_event_header	header;

		u32				pid;
		u32				tid;
4947
	} event_id;
4948 4949
};

4950 4951 4952 4953 4954
static int perf_event_comm_match(struct perf_event *event)
{
	return event->attr.comm;
}

4955
static void perf_event_comm_output(struct perf_event *event,
4956
				   void *data)
4957
{
4958
	struct perf_comm_event *comm_event = data;
4959
	struct perf_output_handle handle;
4960
	struct perf_sample_data sample;
4961
	int size = comm_event->event_id.header.size;
4962 4963
	int ret;

4964 4965 4966
	if (!perf_event_comm_match(event))
		return;

4967 4968
	perf_event_header__init_id(&comm_event->event_id.header, &sample, event);
	ret = perf_output_begin(&handle, event,
4969
				comm_event->event_id.header.size);
4970 4971

	if (ret)
4972
		goto out;
4973

4974 4975
	comm_event->event_id.pid = perf_event_pid(event, comm_event->task);
	comm_event->event_id.tid = perf_event_tid(event, comm_event->task);
4976

4977
	perf_output_put(&handle, comm_event->event_id);
4978
	__output_copy(&handle, comm_event->comm,
4979
				   comm_event->comm_size);
4980 4981 4982

	perf_event__output_id_sample(event, &handle, &sample);

4983
	perf_output_end(&handle);
4984 4985
out:
	comm_event->event_id.header.size = size;
4986 4987
}

4988
static void perf_event_comm_event(struct perf_comm_event *comm_event)
4989
{
4990
	char comm[TASK_COMM_LEN];
4991 4992
	unsigned int size;

4993
	memset(comm, 0, sizeof(comm));
4994
	strlcpy(comm, comm_event->task->comm, sizeof(comm));
4995
	size = ALIGN(strlen(comm)+1, sizeof(u64));
4996 4997 4998 4999

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

5000
	comm_event->event_id.header.size = sizeof(comm_event->event_id) + size;
P
Peter Zijlstra 已提交
5001

5002
	perf_event_aux(perf_event_comm_output,
5003 5004
		       comm_event,
		       NULL);
5005 5006
}

5007
void perf_event_comm(struct task_struct *task)
5008
{
5009
	struct perf_comm_event comm_event;
P
Peter Zijlstra 已提交
5010 5011
	struct perf_event_context *ctx;
	int ctxn;
5012

5013
	rcu_read_lock();
P
Peter Zijlstra 已提交
5014 5015 5016 5017
	for_each_task_context_nr(ctxn) {
		ctx = task->perf_event_ctxp[ctxn];
		if (!ctx)
			continue;
5018

P
Peter Zijlstra 已提交
5019 5020
		perf_event_enable_on_exec(ctx);
	}
5021
	rcu_read_unlock();
5022

5023
	if (!atomic_read(&nr_comm_events))
5024
		return;
5025

5026
	comm_event = (struct perf_comm_event){
5027
		.task	= task,
5028 5029
		/* .comm      */
		/* .comm_size */
5030
		.event_id  = {
5031
			.header = {
5032
				.type = PERF_RECORD_COMM,
5033 5034 5035 5036 5037
				.misc = 0,
				/* .size */
			},
			/* .pid */
			/* .tid */
5038 5039 5040
		},
	};

5041
	perf_event_comm_event(&comm_event);
5042 5043
}

5044 5045 5046 5047 5048
/*
 * mmap tracking
 */

struct perf_mmap_event {
5049 5050 5051 5052
	struct vm_area_struct	*vma;

	const char		*file_name;
	int			file_size;
5053 5054 5055
	int			maj, min;
	u64			ino;
	u64			ino_generation;
5056 5057 5058 5059 5060 5061 5062 5063 5064

	struct {
		struct perf_event_header	header;

		u32				pid;
		u32				tid;
		u64				start;
		u64				len;
		u64				pgoff;
5065
	} event_id;
5066 5067
};

5068 5069 5070 5071 5072 5073 5074 5075
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) ||
5076
	       (executable && (event->attr.mmap || event->attr.mmap2));
5077 5078
}

5079
static void perf_event_mmap_output(struct perf_event *event,
5080
				   void *data)
5081
{
5082
	struct perf_mmap_event *mmap_event = data;
5083
	struct perf_output_handle handle;
5084
	struct perf_sample_data sample;
5085
	int size = mmap_event->event_id.header.size;
5086
	int ret;
5087

5088 5089 5090
	if (!perf_event_mmap_match(event, data))
		return;

5091 5092 5093 5094 5095
	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);
5096
		mmap_event->event_id.header.size += sizeof(mmap_event->ino_generation);
5097 5098
	}

5099 5100
	perf_event_header__init_id(&mmap_event->event_id.header, &sample, event);
	ret = perf_output_begin(&handle, event,
5101
				mmap_event->event_id.header.size);
5102
	if (ret)
5103
		goto out;
5104

5105 5106
	mmap_event->event_id.pid = perf_event_pid(event, current);
	mmap_event->event_id.tid = perf_event_tid(event, current);
5107

5108
	perf_output_put(&handle, mmap_event->event_id);
5109 5110 5111 5112 5113 5114 5115 5116

	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);
	}

5117
	__output_copy(&handle, mmap_event->file_name,
5118
				   mmap_event->file_size);
5119 5120 5121

	perf_event__output_id_sample(event, &handle, &sample);

5122
	perf_output_end(&handle);
5123 5124
out:
	mmap_event->event_id.header.size = size;
5125 5126
}

5127
static void perf_event_mmap_event(struct perf_mmap_event *mmap_event)
5128
{
5129 5130
	struct vm_area_struct *vma = mmap_event->vma;
	struct file *file = vma->vm_file;
5131 5132
	int maj = 0, min = 0;
	u64 ino = 0, gen = 0;
5133 5134 5135
	unsigned int size;
	char tmp[16];
	char *buf = NULL;
5136
	char *name;
5137

5138
	if (file) {
5139 5140
		struct inode *inode;
		dev_t dev;
5141

5142
		buf = kmalloc(PATH_MAX, GFP_KERNEL);
5143
		if (!buf) {
5144 5145
			name = "//enomem";
			goto cpy_name;
5146
		}
5147
		/*
5148
		 * d_path() works from the end of the rb backwards, so we
5149 5150 5151
		 * need to add enough zero bytes after the string to handle
		 * the 64bit alignment we do later.
		 */
5152
		name = d_path(&file->f_path, buf, PATH_MAX - sizeof(u64));
5153
		if (IS_ERR(name)) {
5154 5155
			name = "//toolong";
			goto cpy_name;
5156
		}
5157 5158 5159 5160 5161 5162
		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);
5163
		goto got_name;
5164
	} else {
5165
		name = (char *)arch_vma_name(vma);
5166 5167
		if (name)
			goto cpy_name;
5168

5169
		if (vma->vm_start <= vma->vm_mm->start_brk &&
5170
				vma->vm_end >= vma->vm_mm->brk) {
5171 5172
			name = "[heap]";
			goto cpy_name;
5173 5174
		}
		if (vma->vm_start <= vma->vm_mm->start_stack &&
5175
				vma->vm_end >= vma->vm_mm->start_stack) {
5176 5177
			name = "[stack]";
			goto cpy_name;
5178 5179
		}

5180 5181
		name = "//anon";
		goto cpy_name;
5182 5183
	}

5184 5185 5186
cpy_name:
	strlcpy(tmp, name, sizeof(tmp));
	name = tmp;
5187
got_name:
5188 5189 5190 5191 5192 5193 5194 5195
	/*
	 * 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';
5196 5197 5198

	mmap_event->file_name = name;
	mmap_event->file_size = size;
5199 5200 5201 5202
	mmap_event->maj = maj;
	mmap_event->min = min;
	mmap_event->ino = ino;
	mmap_event->ino_generation = gen;
5203

5204 5205 5206
	if (!(vma->vm_flags & VM_EXEC))
		mmap_event->event_id.header.misc |= PERF_RECORD_MISC_MMAP_DATA;

5207
	mmap_event->event_id.header.size = sizeof(mmap_event->event_id) + size;
5208

5209
	perf_event_aux(perf_event_mmap_output,
5210 5211
		       mmap_event,
		       NULL);
5212

5213 5214 5215
	kfree(buf);
}

5216
void perf_event_mmap(struct vm_area_struct *vma)
5217
{
5218 5219
	struct perf_mmap_event mmap_event;

5220
	if (!atomic_read(&nr_mmap_events))
5221 5222 5223
		return;

	mmap_event = (struct perf_mmap_event){
5224
		.vma	= vma,
5225 5226
		/* .file_name */
		/* .file_size */
5227
		.event_id  = {
5228
			.header = {
5229
				.type = PERF_RECORD_MMAP,
5230
				.misc = PERF_RECORD_MISC_USER,
5231 5232 5233 5234
				/* .size */
			},
			/* .pid */
			/* .tid */
5235 5236
			.start  = vma->vm_start,
			.len    = vma->vm_end - vma->vm_start,
5237
			.pgoff  = (u64)vma->vm_pgoff << PAGE_SHIFT,
5238
		},
5239 5240 5241 5242
		/* .maj (attr_mmap2 only) */
		/* .min (attr_mmap2 only) */
		/* .ino (attr_mmap2 only) */
		/* .ino_generation (attr_mmap2 only) */
5243 5244
	};

5245
	perf_event_mmap_event(&mmap_event);
5246 5247
}

5248 5249 5250 5251
/*
 * IRQ throttle logging
 */

5252
static void perf_log_throttle(struct perf_event *event, int enable)
5253 5254
{
	struct perf_output_handle handle;
5255
	struct perf_sample_data sample;
5256 5257 5258 5259 5260
	int ret;

	struct {
		struct perf_event_header	header;
		u64				time;
5261
		u64				id;
5262
		u64				stream_id;
5263 5264
	} throttle_event = {
		.header = {
5265
			.type = PERF_RECORD_THROTTLE,
5266 5267 5268
			.misc = 0,
			.size = sizeof(throttle_event),
		},
P
Peter Zijlstra 已提交
5269
		.time		= perf_clock(),
5270 5271
		.id		= primary_event_id(event),
		.stream_id	= event->id,
5272 5273
	};

5274
	if (enable)
5275
		throttle_event.header.type = PERF_RECORD_UNTHROTTLE;
5276

5277 5278 5279
	perf_event_header__init_id(&throttle_event.header, &sample, event);

	ret = perf_output_begin(&handle, event,
5280
				throttle_event.header.size);
5281 5282 5283 5284
	if (ret)
		return;

	perf_output_put(&handle, throttle_event);
5285
	perf_event__output_id_sample(event, &handle, &sample);
5286 5287 5288
	perf_output_end(&handle);
}

5289
/*
5290
 * Generic event overflow handling, sampling.
5291 5292
 */

5293
static int __perf_event_overflow(struct perf_event *event,
5294 5295
				   int throttle, struct perf_sample_data *data,
				   struct pt_regs *regs)
5296
{
5297 5298
	int events = atomic_read(&event->event_limit);
	struct hw_perf_event *hwc = &event->hw;
5299
	u64 seq;
5300 5301
	int ret = 0;

5302 5303 5304 5305 5306 5307 5308
	/*
	 * Non-sampling counters might still use the PMI to fold short
	 * hardware counters, ignore those.
	 */
	if (unlikely(!is_sampling_event(event)))
		return 0;

5309 5310 5311 5312 5313 5314 5315 5316 5317
	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
5318 5319
			hwc->interrupts = MAX_INTERRUPTS;
			perf_log_throttle(event, 0);
5320
			tick_nohz_full_kick();
5321 5322
			ret = 1;
		}
5323
	}
5324

5325
	if (event->attr.freq) {
P
Peter Zijlstra 已提交
5326
		u64 now = perf_clock();
5327
		s64 delta = now - hwc->freq_time_stamp;
5328

5329
		hwc->freq_time_stamp = now;
5330

5331
		if (delta > 0 && delta < 2*TICK_NSEC)
5332
			perf_adjust_period(event, delta, hwc->last_period, true);
5333 5334
	}

5335 5336
	/*
	 * XXX event_limit might not quite work as expected on inherited
5337
	 * events
5338 5339
	 */

5340 5341
	event->pending_kill = POLL_IN;
	if (events && atomic_dec_and_test(&event->event_limit)) {
5342
		ret = 1;
5343
		event->pending_kill = POLL_HUP;
5344 5345
		event->pending_disable = 1;
		irq_work_queue(&event->pending);
5346 5347
	}

5348
	if (event->overflow_handler)
5349
		event->overflow_handler(event, data, regs);
5350
	else
5351
		perf_event_output(event, data, regs);
5352

P
Peter Zijlstra 已提交
5353
	if (event->fasync && event->pending_kill) {
5354 5355
		event->pending_wakeup = 1;
		irq_work_queue(&event->pending);
P
Peter Zijlstra 已提交
5356 5357
	}

5358
	return ret;
5359 5360
}

5361
int perf_event_overflow(struct perf_event *event,
5362 5363
			  struct perf_sample_data *data,
			  struct pt_regs *regs)
5364
{
5365
	return __perf_event_overflow(event, 1, data, regs);
5366 5367
}

5368
/*
5369
 * Generic software event infrastructure
5370 5371
 */

5372 5373 5374 5375 5376 5377 5378 5379 5380 5381 5382
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);

5383
/*
5384 5385
 * We directly increment event->count and keep a second value in
 * event->hw.period_left to count intervals. This period event
5386 5387 5388 5389
 * is kept in the range [-sample_period, 0] so that we can use the
 * sign as trigger.
 */

5390
u64 perf_swevent_set_period(struct perf_event *event)
5391
{
5392
	struct hw_perf_event *hwc = &event->hw;
5393 5394 5395 5396 5397
	u64 period = hwc->last_period;
	u64 nr, offset;
	s64 old, val;

	hwc->last_period = hwc->sample_period;
5398 5399

again:
5400
	old = val = local64_read(&hwc->period_left);
5401 5402
	if (val < 0)
		return 0;
5403

5404 5405 5406
	nr = div64_u64(period + val, period);
	offset = nr * period;
	val -= offset;
5407
	if (local64_cmpxchg(&hwc->period_left, old, val) != old)
5408
		goto again;
5409

5410
	return nr;
5411 5412
}

5413
static void perf_swevent_overflow(struct perf_event *event, u64 overflow,
5414
				    struct perf_sample_data *data,
5415
				    struct pt_regs *regs)
5416
{
5417
	struct hw_perf_event *hwc = &event->hw;
5418
	int throttle = 0;
5419

5420 5421
	if (!overflow)
		overflow = perf_swevent_set_period(event);
5422

5423 5424
	if (hwc->interrupts == MAX_INTERRUPTS)
		return;
5425

5426
	for (; overflow; overflow--) {
5427
		if (__perf_event_overflow(event, throttle,
5428
					    data, regs)) {
5429 5430 5431 5432 5433 5434
			/*
			 * We inhibit the overflow from happening when
			 * hwc->interrupts == MAX_INTERRUPTS.
			 */
			break;
		}
5435
		throttle = 1;
5436
	}
5437 5438
}

P
Peter Zijlstra 已提交
5439
static void perf_swevent_event(struct perf_event *event, u64 nr,
5440
			       struct perf_sample_data *data,
5441
			       struct pt_regs *regs)
5442
{
5443
	struct hw_perf_event *hwc = &event->hw;
5444

5445
	local64_add(nr, &event->count);
5446

5447 5448 5449
	if (!regs)
		return;

5450
	if (!is_sampling_event(event))
5451
		return;
5452

5453 5454 5455 5456 5457 5458
	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;

5459
	if (nr == 1 && hwc->sample_period == 1 && !event->attr.freq)
5460
		return perf_swevent_overflow(event, 1, data, regs);
5461

5462
	if (local64_add_negative(nr, &hwc->period_left))
5463
		return;
5464

5465
	perf_swevent_overflow(event, 0, data, regs);
5466 5467
}

5468 5469 5470
static int perf_exclude_event(struct perf_event *event,
			      struct pt_regs *regs)
{
P
Peter Zijlstra 已提交
5471
	if (event->hw.state & PERF_HES_STOPPED)
5472
		return 1;
P
Peter Zijlstra 已提交
5473

5474 5475 5476 5477 5478 5479 5480 5481 5482 5483 5484
	if (regs) {
		if (event->attr.exclude_user && user_mode(regs))
			return 1;

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

	return 0;
}

5485
static int perf_swevent_match(struct perf_event *event,
P
Peter Zijlstra 已提交
5486
				enum perf_type_id type,
L
Li Zefan 已提交
5487 5488 5489
				u32 event_id,
				struct perf_sample_data *data,
				struct pt_regs *regs)
5490
{
5491
	if (event->attr.type != type)
5492
		return 0;
5493

5494
	if (event->attr.config != event_id)
5495 5496
		return 0;

5497 5498
	if (perf_exclude_event(event, regs))
		return 0;
5499 5500 5501 5502

	return 1;
}

5503 5504 5505 5506 5507 5508 5509
static inline u64 swevent_hash(u64 type, u32 event_id)
{
	u64 val = event_id | (type << 32);

	return hash_64(val, SWEVENT_HLIST_BITS);
}

5510 5511
static inline struct hlist_head *
__find_swevent_head(struct swevent_hlist *hlist, u64 type, u32 event_id)
5512
{
5513 5514 5515 5516
	u64 hash = swevent_hash(type, event_id);

	return &hlist->heads[hash];
}
5517

5518 5519
/* For the read side: events when they trigger */
static inline struct hlist_head *
5520
find_swevent_head_rcu(struct swevent_htable *swhash, u64 type, u32 event_id)
5521 5522
{
	struct swevent_hlist *hlist;
5523

5524
	hlist = rcu_dereference(swhash->swevent_hlist);
5525 5526 5527
	if (!hlist)
		return NULL;

5528 5529 5530 5531 5532
	return __find_swevent_head(hlist, type, event_id);
}

/* For the event head insertion and removal in the hlist */
static inline struct hlist_head *
5533
find_swevent_head(struct swevent_htable *swhash, struct perf_event *event)
5534 5535 5536 5537 5538 5539 5540 5541 5542 5543
{
	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.
	 */
5544
	hlist = rcu_dereference_protected(swhash->swevent_hlist,
5545 5546 5547 5548 5549
					  lockdep_is_held(&event->ctx->lock));
	if (!hlist)
		return NULL;

	return __find_swevent_head(hlist, type, event_id);
5550 5551 5552
}

static void do_perf_sw_event(enum perf_type_id type, u32 event_id,
5553
				    u64 nr,
5554 5555
				    struct perf_sample_data *data,
				    struct pt_regs *regs)
5556
{
5557
	struct swevent_htable *swhash = &__get_cpu_var(swevent_htable);
5558
	struct perf_event *event;
5559
	struct hlist_head *head;
5560

5561
	rcu_read_lock();
5562
	head = find_swevent_head_rcu(swhash, type, event_id);
5563 5564 5565
	if (!head)
		goto end;

5566
	hlist_for_each_entry_rcu(event, head, hlist_entry) {
L
Li Zefan 已提交
5567
		if (perf_swevent_match(event, type, event_id, data, regs))
5568
			perf_swevent_event(event, nr, data, regs);
5569
	}
5570 5571
end:
	rcu_read_unlock();
5572 5573
}

5574
int perf_swevent_get_recursion_context(void)
P
Peter Zijlstra 已提交
5575
{
5576
	struct swevent_htable *swhash = &__get_cpu_var(swevent_htable);
P
Peter Zijlstra 已提交
5577

5578
	return get_recursion_context(swhash->recursion);
P
Peter Zijlstra 已提交
5579
}
I
Ingo Molnar 已提交
5580
EXPORT_SYMBOL_GPL(perf_swevent_get_recursion_context);
P
Peter Zijlstra 已提交
5581

5582
inline void perf_swevent_put_recursion_context(int rctx)
5583
{
5584
	struct swevent_htable *swhash = &__get_cpu_var(swevent_htable);
5585

5586
	put_recursion_context(swhash->recursion, rctx);
5587
}
5588

5589
void __perf_sw_event(u32 event_id, u64 nr, struct pt_regs *regs, u64 addr)
5590
{
5591
	struct perf_sample_data data;
5592 5593
	int rctx;

5594
	preempt_disable_notrace();
5595 5596 5597
	rctx = perf_swevent_get_recursion_context();
	if (rctx < 0)
		return;
5598

5599
	perf_sample_data_init(&data, addr, 0);
5600

5601
	do_perf_sw_event(PERF_TYPE_SOFTWARE, event_id, nr, &data, regs);
5602 5603

	perf_swevent_put_recursion_context(rctx);
5604
	preempt_enable_notrace();
5605 5606
}

5607
static void perf_swevent_read(struct perf_event *event)
5608 5609 5610
{
}

P
Peter Zijlstra 已提交
5611
static int perf_swevent_add(struct perf_event *event, int flags)
5612
{
5613
	struct swevent_htable *swhash = &__get_cpu_var(swevent_htable);
5614
	struct hw_perf_event *hwc = &event->hw;
5615 5616
	struct hlist_head *head;

5617
	if (is_sampling_event(event)) {
5618
		hwc->last_period = hwc->sample_period;
5619
		perf_swevent_set_period(event);
5620
	}
5621

P
Peter Zijlstra 已提交
5622 5623
	hwc->state = !(flags & PERF_EF_START);

5624
	head = find_swevent_head(swhash, event);
5625 5626 5627 5628 5629
	if (WARN_ON_ONCE(!head))
		return -EINVAL;

	hlist_add_head_rcu(&event->hlist_entry, head);

5630 5631 5632
	return 0;
}

P
Peter Zijlstra 已提交
5633
static void perf_swevent_del(struct perf_event *event, int flags)
5634
{
5635
	hlist_del_rcu(&event->hlist_entry);
5636 5637
}

P
Peter Zijlstra 已提交
5638
static void perf_swevent_start(struct perf_event *event, int flags)
5639
{
P
Peter Zijlstra 已提交
5640
	event->hw.state = 0;
5641
}
I
Ingo Molnar 已提交
5642

P
Peter Zijlstra 已提交
5643
static void perf_swevent_stop(struct perf_event *event, int flags)
5644
{
P
Peter Zijlstra 已提交
5645
	event->hw.state = PERF_HES_STOPPED;
5646 5647
}

5648 5649
/* Deref the hlist from the update side */
static inline struct swevent_hlist *
5650
swevent_hlist_deref(struct swevent_htable *swhash)
5651
{
5652 5653
	return rcu_dereference_protected(swhash->swevent_hlist,
					 lockdep_is_held(&swhash->hlist_mutex));
5654 5655
}

5656
static void swevent_hlist_release(struct swevent_htable *swhash)
5657
{
5658
	struct swevent_hlist *hlist = swevent_hlist_deref(swhash);
5659

5660
	if (!hlist)
5661 5662
		return;

5663
	rcu_assign_pointer(swhash->swevent_hlist, NULL);
5664
	kfree_rcu(hlist, rcu_head);
5665 5666 5667 5668
}

static void swevent_hlist_put_cpu(struct perf_event *event, int cpu)
{
5669
	struct swevent_htable *swhash = &per_cpu(swevent_htable, cpu);
5670

5671
	mutex_lock(&swhash->hlist_mutex);
5672

5673 5674
	if (!--swhash->hlist_refcount)
		swevent_hlist_release(swhash);
5675

5676
	mutex_unlock(&swhash->hlist_mutex);
5677 5678 5679 5680 5681 5682 5683 5684 5685 5686 5687 5688
}

static void swevent_hlist_put(struct perf_event *event)
{
	int cpu;

	for_each_possible_cpu(cpu)
		swevent_hlist_put_cpu(event, cpu);
}

static int swevent_hlist_get_cpu(struct perf_event *event, int cpu)
{
5689
	struct swevent_htable *swhash = &per_cpu(swevent_htable, cpu);
5690 5691
	int err = 0;

5692
	mutex_lock(&swhash->hlist_mutex);
5693

5694
	if (!swevent_hlist_deref(swhash) && cpu_online(cpu)) {
5695 5696 5697 5698 5699 5700 5701
		struct swevent_hlist *hlist;

		hlist = kzalloc(sizeof(*hlist), GFP_KERNEL);
		if (!hlist) {
			err = -ENOMEM;
			goto exit;
		}
5702
		rcu_assign_pointer(swhash->swevent_hlist, hlist);
5703
	}
5704
	swhash->hlist_refcount++;
P
Peter Zijlstra 已提交
5705
exit:
5706
	mutex_unlock(&swhash->hlist_mutex);
5707 5708 5709 5710 5711 5712 5713 5714 5715 5716 5717 5718 5719 5720 5721 5722 5723 5724 5725 5726

	return err;
}

static int swevent_hlist_get(struct perf_event *event)
{
	int err;
	int cpu, failed_cpu;

	get_online_cpus();
	for_each_possible_cpu(cpu) {
		err = swevent_hlist_get_cpu(event, cpu);
		if (err) {
			failed_cpu = cpu;
			goto fail;
		}
	}
	put_online_cpus();

	return 0;
P
Peter Zijlstra 已提交
5727
fail:
5728 5729 5730 5731 5732 5733 5734 5735 5736 5737
	for_each_possible_cpu(cpu) {
		if (cpu == failed_cpu)
			break;
		swevent_hlist_put_cpu(event, cpu);
	}

	put_online_cpus();
	return err;
}

5738
struct static_key perf_swevent_enabled[PERF_COUNT_SW_MAX];
5739

5740 5741 5742
static void sw_perf_event_destroy(struct perf_event *event)
{
	u64 event_id = event->attr.config;
5743

5744 5745
	WARN_ON(event->parent);

5746
	static_key_slow_dec(&perf_swevent_enabled[event_id]);
5747 5748 5749 5750 5751
	swevent_hlist_put(event);
}

static int perf_swevent_init(struct perf_event *event)
{
5752
	u64 event_id = event->attr.config;
5753 5754 5755 5756

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

5757 5758 5759 5760 5761 5762
	/*
	 * no branch sampling for software events
	 */
	if (has_branch_stack(event))
		return -EOPNOTSUPP;

5763 5764 5765 5766 5767 5768 5769 5770 5771
	switch (event_id) {
	case PERF_COUNT_SW_CPU_CLOCK:
	case PERF_COUNT_SW_TASK_CLOCK:
		return -ENOENT;

	default:
		break;
	}

5772
	if (event_id >= PERF_COUNT_SW_MAX)
5773 5774 5775 5776 5777 5778 5779 5780 5781
		return -ENOENT;

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

		err = swevent_hlist_get(event);
		if (err)
			return err;

5782
		static_key_slow_inc(&perf_swevent_enabled[event_id]);
5783 5784 5785 5786 5787 5788
		event->destroy = sw_perf_event_destroy;
	}

	return 0;
}

5789 5790 5791 5792 5793
static int perf_swevent_event_idx(struct perf_event *event)
{
	return 0;
}

5794
static struct pmu perf_swevent = {
5795
	.task_ctx_nr	= perf_sw_context,
5796

5797
	.event_init	= perf_swevent_init,
P
Peter Zijlstra 已提交
5798 5799 5800 5801
	.add		= perf_swevent_add,
	.del		= perf_swevent_del,
	.start		= perf_swevent_start,
	.stop		= perf_swevent_stop,
5802
	.read		= perf_swevent_read,
5803 5804

	.event_idx	= perf_swevent_event_idx,
5805 5806
};

5807 5808
#ifdef CONFIG_EVENT_TRACING

5809 5810 5811 5812 5813 5814 5815 5816 5817 5818 5819 5820 5821 5822
static int perf_tp_filter_match(struct perf_event *event,
				struct perf_sample_data *data)
{
	void *record = data->raw->data;

	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)
{
5823 5824
	if (event->hw.state & PERF_HES_STOPPED)
		return 0;
5825 5826 5827 5828
	/*
	 * All tracepoints are from kernel-space.
	 */
	if (event->attr.exclude_kernel)
5829 5830 5831 5832 5833 5834 5835 5836 5837
		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,
5838 5839
		   struct pt_regs *regs, struct hlist_head *head, int rctx,
		   struct task_struct *task)
5840 5841
{
	struct perf_sample_data data;
5842 5843
	struct perf_event *event;

5844 5845 5846 5847 5848
	struct perf_raw_record raw = {
		.size = entry_size,
		.data = record,
	};

5849
	perf_sample_data_init(&data, addr, 0);
5850 5851
	data.raw = &raw;

5852
	hlist_for_each_entry_rcu(event, head, hlist_entry) {
5853
		if (perf_tp_event_match(event, &data, regs))
5854
			perf_swevent_event(event, count, &data, regs);
5855
	}
5856

5857 5858 5859 5860 5861 5862 5863 5864 5865 5866 5867 5868 5869 5870 5871 5872 5873 5874 5875 5876 5877 5878 5879 5880 5881
	/*
	 * 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();
	}

5882
	perf_swevent_put_recursion_context(rctx);
5883 5884 5885
}
EXPORT_SYMBOL_GPL(perf_tp_event);

5886
static void tp_perf_event_destroy(struct perf_event *event)
5887
{
5888
	perf_trace_destroy(event);
5889 5890
}

5891
static int perf_tp_event_init(struct perf_event *event)
5892
{
5893 5894
	int err;

5895 5896 5897
	if (event->attr.type != PERF_TYPE_TRACEPOINT)
		return -ENOENT;

5898 5899 5900 5901 5902 5903
	/*
	 * no branch sampling for tracepoint events
	 */
	if (has_branch_stack(event))
		return -EOPNOTSUPP;

5904 5905
	err = perf_trace_init(event);
	if (err)
5906
		return err;
5907

5908
	event->destroy = tp_perf_event_destroy;
5909

5910 5911 5912 5913
	return 0;
}

static struct pmu perf_tracepoint = {
5914 5915
	.task_ctx_nr	= perf_sw_context,

5916
	.event_init	= perf_tp_event_init,
P
Peter Zijlstra 已提交
5917 5918 5919 5920
	.add		= perf_trace_add,
	.del		= perf_trace_del,
	.start		= perf_swevent_start,
	.stop		= perf_swevent_stop,
5921
	.read		= perf_swevent_read,
5922 5923

	.event_idx	= perf_swevent_event_idx,
5924 5925 5926 5927
};

static inline void perf_tp_register(void)
{
P
Peter Zijlstra 已提交
5928
	perf_pmu_register(&perf_tracepoint, "tracepoint", PERF_TYPE_TRACEPOINT);
5929
}
L
Li Zefan 已提交
5930 5931 5932 5933 5934 5935 5936 5937 5938 5939 5940 5941 5942 5943 5944 5945 5946 5947 5948 5949 5950 5951 5952 5953

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);
}

5954
#else
L
Li Zefan 已提交
5955

5956
static inline void perf_tp_register(void)
5957 5958
{
}
L
Li Zefan 已提交
5959 5960 5961 5962 5963 5964 5965 5966 5967 5968

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)
{
}

5969
#endif /* CONFIG_EVENT_TRACING */
5970

5971
#ifdef CONFIG_HAVE_HW_BREAKPOINT
5972
void perf_bp_event(struct perf_event *bp, void *data)
5973
{
5974 5975 5976
	struct perf_sample_data sample;
	struct pt_regs *regs = data;

5977
	perf_sample_data_init(&sample, bp->attr.bp_addr, 0);
5978

P
Peter Zijlstra 已提交
5979
	if (!bp->hw.state && !perf_exclude_event(bp, regs))
5980
		perf_swevent_event(bp, 1, &sample, regs);
5981 5982 5983
}
#endif

5984 5985 5986
/*
 * hrtimer based swevent callback
 */
5987

5988
static enum hrtimer_restart perf_swevent_hrtimer(struct hrtimer *hrtimer)
5989
{
5990 5991 5992 5993 5994
	enum hrtimer_restart ret = HRTIMER_RESTART;
	struct perf_sample_data data;
	struct pt_regs *regs;
	struct perf_event *event;
	u64 period;
5995

5996
	event = container_of(hrtimer, struct perf_event, hw.hrtimer);
P
Peter Zijlstra 已提交
5997 5998 5999 6000

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

6001
	event->pmu->read(event);
6002

6003
	perf_sample_data_init(&data, 0, event->hw.last_period);
6004 6005 6006
	regs = get_irq_regs();

	if (regs && !perf_exclude_event(event, regs)) {
6007
		if (!(event->attr.exclude_idle && is_idle_task(current)))
6008
			if (__perf_event_overflow(event, 1, &data, regs))
6009 6010
				ret = HRTIMER_NORESTART;
	}
6011

6012 6013
	period = max_t(u64, 10000, event->hw.sample_period);
	hrtimer_forward_now(hrtimer, ns_to_ktime(period));
6014

6015
	return ret;
6016 6017
}

6018
static void perf_swevent_start_hrtimer(struct perf_event *event)
6019
{
6020
	struct hw_perf_event *hwc = &event->hw;
6021 6022 6023 6024
	s64 period;

	if (!is_sampling_event(event))
		return;
6025

6026 6027 6028 6029
	period = local64_read(&hwc->period_left);
	if (period) {
		if (period < 0)
			period = 10000;
P
Peter Zijlstra 已提交
6030

6031 6032 6033 6034 6035
		local64_set(&hwc->period_left, 0);
	} else {
		period = max_t(u64, 10000, hwc->sample_period);
	}
	__hrtimer_start_range_ns(&hwc->hrtimer,
6036
				ns_to_ktime(period), 0,
6037
				HRTIMER_MODE_REL_PINNED, 0);
6038
}
6039 6040

static void perf_swevent_cancel_hrtimer(struct perf_event *event)
6041
{
6042 6043
	struct hw_perf_event *hwc = &event->hw;

6044
	if (is_sampling_event(event)) {
6045
		ktime_t remaining = hrtimer_get_remaining(&hwc->hrtimer);
P
Peter Zijlstra 已提交
6046
		local64_set(&hwc->period_left, ktime_to_ns(remaining));
6047 6048 6049

		hrtimer_cancel(&hwc->hrtimer);
	}
6050 6051
}

P
Peter Zijlstra 已提交
6052 6053 6054 6055 6056 6057 6058 6059 6060 6061 6062 6063 6064 6065 6066 6067 6068 6069 6070 6071
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);
6072
		hwc->last_period = hwc->sample_period;
P
Peter Zijlstra 已提交
6073 6074 6075 6076
		event->attr.freq = 0;
	}
}

6077 6078 6079 6080 6081
/*
 * Software event: cpu wall time clock
 */

static void cpu_clock_event_update(struct perf_event *event)
6082
{
6083 6084 6085
	s64 prev;
	u64 now;

P
Peter Zijlstra 已提交
6086
	now = local_clock();
6087 6088
	prev = local64_xchg(&event->hw.prev_count, now);
	local64_add(now - prev, &event->count);
6089 6090
}

P
Peter Zijlstra 已提交
6091
static void cpu_clock_event_start(struct perf_event *event, int flags)
6092
{
P
Peter Zijlstra 已提交
6093
	local64_set(&event->hw.prev_count, local_clock());
6094 6095 6096
	perf_swevent_start_hrtimer(event);
}

P
Peter Zijlstra 已提交
6097
static void cpu_clock_event_stop(struct perf_event *event, int flags)
6098
{
6099 6100 6101
	perf_swevent_cancel_hrtimer(event);
	cpu_clock_event_update(event);
}
6102

P
Peter Zijlstra 已提交
6103 6104 6105 6106 6107 6108 6109 6110 6111 6112 6113 6114 6115
static int cpu_clock_event_add(struct perf_event *event, int flags)
{
	if (flags & PERF_EF_START)
		cpu_clock_event_start(event, flags);

	return 0;
}

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

6116 6117 6118 6119
static void cpu_clock_event_read(struct perf_event *event)
{
	cpu_clock_event_update(event);
}
6120

6121 6122 6123 6124 6125 6126 6127 6128
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;

6129 6130 6131 6132 6133 6134
	/*
	 * no branch sampling for software events
	 */
	if (has_branch_stack(event))
		return -EOPNOTSUPP;

P
Peter Zijlstra 已提交
6135 6136
	perf_swevent_init_hrtimer(event);

6137
	return 0;
6138 6139
}

6140
static struct pmu perf_cpu_clock = {
6141 6142
	.task_ctx_nr	= perf_sw_context,

6143
	.event_init	= cpu_clock_event_init,
P
Peter Zijlstra 已提交
6144 6145 6146 6147
	.add		= cpu_clock_event_add,
	.del		= cpu_clock_event_del,
	.start		= cpu_clock_event_start,
	.stop		= cpu_clock_event_stop,
6148
	.read		= cpu_clock_event_read,
6149 6150

	.event_idx	= perf_swevent_event_idx,
6151 6152 6153 6154 6155 6156 6157
};

/*
 * Software event: task time clock
 */

static void task_clock_event_update(struct perf_event *event, u64 now)
6158
{
6159 6160
	u64 prev;
	s64 delta;
6161

6162 6163 6164 6165
	prev = local64_xchg(&event->hw.prev_count, now);
	delta = now - prev;
	local64_add(delta, &event->count);
}
6166

P
Peter Zijlstra 已提交
6167
static void task_clock_event_start(struct perf_event *event, int flags)
6168
{
P
Peter Zijlstra 已提交
6169
	local64_set(&event->hw.prev_count, event->ctx->time);
6170 6171 6172
	perf_swevent_start_hrtimer(event);
}

P
Peter Zijlstra 已提交
6173
static void task_clock_event_stop(struct perf_event *event, int flags)
6174 6175 6176
{
	perf_swevent_cancel_hrtimer(event);
	task_clock_event_update(event, event->ctx->time);
P
Peter Zijlstra 已提交
6177 6178 6179 6180 6181 6182
}

static int task_clock_event_add(struct perf_event *event, int flags)
{
	if (flags & PERF_EF_START)
		task_clock_event_start(event, flags);
6183

P
Peter Zijlstra 已提交
6184 6185 6186 6187 6188 6189
	return 0;
}

static void task_clock_event_del(struct perf_event *event, int flags)
{
	task_clock_event_stop(event, PERF_EF_UPDATE);
6190 6191 6192 6193
}

static void task_clock_event_read(struct perf_event *event)
{
6194 6195 6196
	u64 now = perf_clock();
	u64 delta = now - event->ctx->timestamp;
	u64 time = event->ctx->time + delta;
6197 6198 6199 6200 6201

	task_clock_event_update(event, time);
}

static int task_clock_event_init(struct perf_event *event)
L
Li Zefan 已提交
6202
{
6203 6204 6205 6206 6207 6208
	if (event->attr.type != PERF_TYPE_SOFTWARE)
		return -ENOENT;

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

6209 6210 6211 6212 6213 6214
	/*
	 * no branch sampling for software events
	 */
	if (has_branch_stack(event))
		return -EOPNOTSUPP;

P
Peter Zijlstra 已提交
6215 6216
	perf_swevent_init_hrtimer(event);

6217
	return 0;
L
Li Zefan 已提交
6218 6219
}

6220
static struct pmu perf_task_clock = {
6221 6222
	.task_ctx_nr	= perf_sw_context,

6223
	.event_init	= task_clock_event_init,
P
Peter Zijlstra 已提交
6224 6225 6226 6227
	.add		= task_clock_event_add,
	.del		= task_clock_event_del,
	.start		= task_clock_event_start,
	.stop		= task_clock_event_stop,
6228
	.read		= task_clock_event_read,
6229 6230

	.event_idx	= perf_swevent_event_idx,
6231
};
L
Li Zefan 已提交
6232

P
Peter Zijlstra 已提交
6233
static void perf_pmu_nop_void(struct pmu *pmu)
6234 6235
{
}
L
Li Zefan 已提交
6236

P
Peter Zijlstra 已提交
6237
static int perf_pmu_nop_int(struct pmu *pmu)
L
Li Zefan 已提交
6238
{
P
Peter Zijlstra 已提交
6239
	return 0;
L
Li Zefan 已提交
6240 6241
}

P
Peter Zijlstra 已提交
6242
static void perf_pmu_start_txn(struct pmu *pmu)
L
Li Zefan 已提交
6243
{
P
Peter Zijlstra 已提交
6244
	perf_pmu_disable(pmu);
L
Li Zefan 已提交
6245 6246
}

P
Peter Zijlstra 已提交
6247 6248 6249 6250 6251
static int perf_pmu_commit_txn(struct pmu *pmu)
{
	perf_pmu_enable(pmu);
	return 0;
}
6252

P
Peter Zijlstra 已提交
6253
static void perf_pmu_cancel_txn(struct pmu *pmu)
6254
{
P
Peter Zijlstra 已提交
6255
	perf_pmu_enable(pmu);
6256 6257
}

6258 6259 6260 6261 6262
static int perf_event_idx_default(struct perf_event *event)
{
	return event->hw.idx + 1;
}

P
Peter Zijlstra 已提交
6263 6264 6265 6266 6267
/*
 * Ensures all contexts with the same task_ctx_nr have the same
 * pmu_cpu_context too.
 */
static void *find_pmu_context(int ctxn)
6268
{
P
Peter Zijlstra 已提交
6269
	struct pmu *pmu;
6270

P
Peter Zijlstra 已提交
6271 6272
	if (ctxn < 0)
		return NULL;
6273

P
Peter Zijlstra 已提交
6274 6275 6276 6277
	list_for_each_entry(pmu, &pmus, entry) {
		if (pmu->task_ctx_nr == ctxn)
			return pmu->pmu_cpu_context;
	}
6278

P
Peter Zijlstra 已提交
6279
	return NULL;
6280 6281
}

6282
static void update_pmu_context(struct pmu *pmu, struct pmu *old_pmu)
6283
{
6284 6285 6286 6287 6288 6289 6290
	int cpu;

	for_each_possible_cpu(cpu) {
		struct perf_cpu_context *cpuctx;

		cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);

6291 6292
		if (cpuctx->unique_pmu == old_pmu)
			cpuctx->unique_pmu = pmu;
6293 6294 6295 6296 6297 6298
	}
}

static void free_pmu_context(struct pmu *pmu)
{
	struct pmu *i;
6299

P
Peter Zijlstra 已提交
6300
	mutex_lock(&pmus_lock);
6301
	/*
P
Peter Zijlstra 已提交
6302
	 * Like a real lame refcount.
6303
	 */
6304 6305 6306
	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
6307
			goto out;
6308
		}
P
Peter Zijlstra 已提交
6309
	}
6310

6311
	free_percpu(pmu->pmu_cpu_context);
P
Peter Zijlstra 已提交
6312 6313
out:
	mutex_unlock(&pmus_lock);
6314
}
P
Peter Zijlstra 已提交
6315
static struct idr pmu_idr;
6316

P
Peter Zijlstra 已提交
6317 6318 6319 6320 6321 6322 6323
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);
}
6324
static DEVICE_ATTR_RO(type);
P
Peter Zijlstra 已提交
6325

6326 6327 6328 6329 6330 6331 6332 6333 6334 6335 6336 6337 6338 6339 6340 6341 6342 6343 6344 6345 6346 6347 6348 6349 6350 6351 6352 6353 6354 6355 6356 6357 6358 6359 6360 6361 6362 6363 6364 6365 6366 6367 6368
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);
}

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;

	pmu->hrtimer_interval_ms = timer;

	/* update all cpuctx for this PMU */
	for_each_possible_cpu(cpu) {
		struct perf_cpu_context *cpuctx;
		cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
		cpuctx->hrtimer_interval = ns_to_ktime(NSEC_PER_MSEC * timer);

		if (hrtimer_active(&cpuctx->hrtimer))
			hrtimer_forward_now(&cpuctx->hrtimer, cpuctx->hrtimer_interval);
	}

	return count;
}
6369
static DEVICE_ATTR_RW(perf_event_mux_interval_ms);
6370

6371 6372 6373 6374
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
6375
};
6376
ATTRIBUTE_GROUPS(pmu_dev);
P
Peter Zijlstra 已提交
6377 6378 6379 6380

static int pmu_bus_running;
static struct bus_type pmu_bus = {
	.name		= "event_source",
6381
	.dev_groups	= pmu_dev_groups,
P
Peter Zijlstra 已提交
6382 6383 6384 6385 6386 6387 6388 6389 6390 6391 6392 6393 6394 6395 6396
};

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;

6397
	pmu->dev->groups = pmu->attr_groups;
P
Peter Zijlstra 已提交
6398 6399 6400 6401 6402 6403 6404 6405 6406 6407 6408 6409 6410 6411 6412 6413 6414 6415 6416 6417
	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;
}

6418
static struct lock_class_key cpuctx_mutex;
6419
static struct lock_class_key cpuctx_lock;
6420

6421
int perf_pmu_register(struct pmu *pmu, const char *name, int type)
6422
{
P
Peter Zijlstra 已提交
6423
	int cpu, ret;
6424

6425
	mutex_lock(&pmus_lock);
P
Peter Zijlstra 已提交
6426 6427 6428 6429
	ret = -ENOMEM;
	pmu->pmu_disable_count = alloc_percpu(int);
	if (!pmu->pmu_disable_count)
		goto unlock;
6430

P
Peter Zijlstra 已提交
6431 6432 6433 6434 6435 6436
	pmu->type = -1;
	if (!name)
		goto skip_type;
	pmu->name = name;

	if (type < 0) {
T
Tejun Heo 已提交
6437 6438 6439
		type = idr_alloc(&pmu_idr, pmu, PERF_TYPE_MAX, 0, GFP_KERNEL);
		if (type < 0) {
			ret = type;
P
Peter Zijlstra 已提交
6440 6441 6442 6443 6444
			goto free_pdc;
		}
	}
	pmu->type = type;

P
Peter Zijlstra 已提交
6445 6446 6447 6448 6449 6450
	if (pmu_bus_running) {
		ret = pmu_dev_alloc(pmu);
		if (ret)
			goto free_idr;
	}

P
Peter Zijlstra 已提交
6451
skip_type:
P
Peter Zijlstra 已提交
6452 6453 6454
	pmu->pmu_cpu_context = find_pmu_context(pmu->task_ctx_nr);
	if (pmu->pmu_cpu_context)
		goto got_cpu_context;
6455

W
Wei Yongjun 已提交
6456
	ret = -ENOMEM;
P
Peter Zijlstra 已提交
6457 6458
	pmu->pmu_cpu_context = alloc_percpu(struct perf_cpu_context);
	if (!pmu->pmu_cpu_context)
P
Peter Zijlstra 已提交
6459
		goto free_dev;
6460

P
Peter Zijlstra 已提交
6461 6462 6463 6464
	for_each_possible_cpu(cpu) {
		struct perf_cpu_context *cpuctx;

		cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
6465
		__perf_event_init_context(&cpuctx->ctx);
6466
		lockdep_set_class(&cpuctx->ctx.mutex, &cpuctx_mutex);
6467
		lockdep_set_class(&cpuctx->ctx.lock, &cpuctx_lock);
6468
		cpuctx->ctx.type = cpu_context;
P
Peter Zijlstra 已提交
6469
		cpuctx->ctx.pmu = pmu;
6470 6471 6472

		__perf_cpu_hrtimer_init(cpuctx, cpu);

6473
		INIT_LIST_HEAD(&cpuctx->rotation_list);
6474
		cpuctx->unique_pmu = pmu;
P
Peter Zijlstra 已提交
6475
	}
6476

P
Peter Zijlstra 已提交
6477
got_cpu_context:
P
Peter Zijlstra 已提交
6478 6479 6480 6481 6482 6483 6484 6485 6486 6487 6488 6489 6490 6491
	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 {
			pmu->start_txn  = perf_pmu_nop_void;
			pmu->commit_txn = perf_pmu_nop_int;
			pmu->cancel_txn = perf_pmu_nop_void;
6492
		}
6493
	}
6494

P
Peter Zijlstra 已提交
6495 6496 6497 6498 6499
	if (!pmu->pmu_enable) {
		pmu->pmu_enable  = perf_pmu_nop_void;
		pmu->pmu_disable = perf_pmu_nop_void;
	}

6500 6501 6502
	if (!pmu->event_idx)
		pmu->event_idx = perf_event_idx_default;

6503
	list_add_rcu(&pmu->entry, &pmus);
P
Peter Zijlstra 已提交
6504 6505
	ret = 0;
unlock:
6506 6507
	mutex_unlock(&pmus_lock);

P
Peter Zijlstra 已提交
6508
	return ret;
P
Peter Zijlstra 已提交
6509

P
Peter Zijlstra 已提交
6510 6511 6512 6513
free_dev:
	device_del(pmu->dev);
	put_device(pmu->dev);

P
Peter Zijlstra 已提交
6514 6515 6516 6517
free_idr:
	if (pmu->type >= PERF_TYPE_MAX)
		idr_remove(&pmu_idr, pmu->type);

P
Peter Zijlstra 已提交
6518 6519 6520
free_pdc:
	free_percpu(pmu->pmu_disable_count);
	goto unlock;
6521 6522
}

6523
void perf_pmu_unregister(struct pmu *pmu)
6524
{
6525 6526 6527
	mutex_lock(&pmus_lock);
	list_del_rcu(&pmu->entry);
	mutex_unlock(&pmus_lock);
6528

6529
	/*
P
Peter Zijlstra 已提交
6530 6531
	 * We dereference the pmu list under both SRCU and regular RCU, so
	 * synchronize against both of those.
6532
	 */
6533
	synchronize_srcu(&pmus_srcu);
P
Peter Zijlstra 已提交
6534
	synchronize_rcu();
6535

P
Peter Zijlstra 已提交
6536
	free_percpu(pmu->pmu_disable_count);
P
Peter Zijlstra 已提交
6537 6538
	if (pmu->type >= PERF_TYPE_MAX)
		idr_remove(&pmu_idr, pmu->type);
P
Peter Zijlstra 已提交
6539 6540
	device_del(pmu->dev);
	put_device(pmu->dev);
6541
	free_pmu_context(pmu);
6542
}
6543

6544 6545 6546 6547
struct pmu *perf_init_event(struct perf_event *event)
{
	struct pmu *pmu = NULL;
	int idx;
6548
	int ret;
6549 6550

	idx = srcu_read_lock(&pmus_srcu);
P
Peter Zijlstra 已提交
6551 6552 6553 6554

	rcu_read_lock();
	pmu = idr_find(&pmu_idr, event->attr.type);
	rcu_read_unlock();
6555
	if (pmu) {
6556
		event->pmu = pmu;
6557 6558 6559
		ret = pmu->event_init(event);
		if (ret)
			pmu = ERR_PTR(ret);
P
Peter Zijlstra 已提交
6560
		goto unlock;
6561
	}
P
Peter Zijlstra 已提交
6562

6563
	list_for_each_entry_rcu(pmu, &pmus, entry) {
6564
		event->pmu = pmu;
6565
		ret = pmu->event_init(event);
6566
		if (!ret)
P
Peter Zijlstra 已提交
6567
			goto unlock;
6568

6569 6570
		if (ret != -ENOENT) {
			pmu = ERR_PTR(ret);
P
Peter Zijlstra 已提交
6571
			goto unlock;
6572
		}
6573
	}
P
Peter Zijlstra 已提交
6574 6575
	pmu = ERR_PTR(-ENOENT);
unlock:
6576
	srcu_read_unlock(&pmus_srcu, idx);
6577

6578
	return pmu;
6579 6580
}

6581 6582 6583 6584 6585 6586 6587 6588 6589 6590 6591 6592 6593
static void account_event_cpu(struct perf_event *event, int cpu)
{
	if (event->parent)
		return;

	if (has_branch_stack(event)) {
		if (!(event->attach_state & PERF_ATTACH_TASK))
			atomic_inc(&per_cpu(perf_branch_stack_events, cpu));
	}
	if (is_cgroup_event(event))
		atomic_inc(&per_cpu(perf_cgroup_events, cpu));
}

6594 6595
static void account_event(struct perf_event *event)
{
6596 6597 6598
	if (event->parent)
		return;

6599 6600 6601 6602 6603 6604 6605 6606
	if (event->attach_state & PERF_ATTACH_TASK)
		static_key_slow_inc(&perf_sched_events.key);
	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);
6607 6608 6609 6610
	if (event->attr.freq) {
		if (atomic_inc_return(&nr_freq_events) == 1)
			tick_nohz_full_kick_all();
	}
6611
	if (has_branch_stack(event))
6612
		static_key_slow_inc(&perf_sched_events.key);
6613
	if (is_cgroup_event(event))
6614
		static_key_slow_inc(&perf_sched_events.key);
6615 6616

	account_event_cpu(event, event->cpu);
6617 6618
}

T
Thomas Gleixner 已提交
6619
/*
6620
 * Allocate and initialize a event structure
T
Thomas Gleixner 已提交
6621
 */
6622
static struct perf_event *
6623
perf_event_alloc(struct perf_event_attr *attr, int cpu,
6624 6625 6626
		 struct task_struct *task,
		 struct perf_event *group_leader,
		 struct perf_event *parent_event,
6627 6628
		 perf_overflow_handler_t overflow_handler,
		 void *context)
T
Thomas Gleixner 已提交
6629
{
P
Peter Zijlstra 已提交
6630
	struct pmu *pmu;
6631 6632
	struct perf_event *event;
	struct hw_perf_event *hwc;
6633
	long err = -EINVAL;
T
Thomas Gleixner 已提交
6634

6635 6636 6637 6638 6639
	if ((unsigned)cpu >= nr_cpu_ids) {
		if (!task || cpu != -1)
			return ERR_PTR(-EINVAL);
	}

6640
	event = kzalloc(sizeof(*event), GFP_KERNEL);
6641
	if (!event)
6642
		return ERR_PTR(-ENOMEM);
T
Thomas Gleixner 已提交
6643

6644
	/*
6645
	 * Single events are their own group leaders, with an
6646 6647 6648
	 * empty sibling list:
	 */
	if (!group_leader)
6649
		group_leader = event;
6650

6651 6652
	mutex_init(&event->child_mutex);
	INIT_LIST_HEAD(&event->child_list);
6653

6654 6655 6656
	INIT_LIST_HEAD(&event->group_entry);
	INIT_LIST_HEAD(&event->event_entry);
	INIT_LIST_HEAD(&event->sibling_list);
6657
	INIT_LIST_HEAD(&event->rb_entry);
6658
	INIT_LIST_HEAD(&event->active_entry);
6659

6660
	init_waitqueue_head(&event->waitq);
6661
	init_irq_work(&event->pending, perf_pending_event);
T
Thomas Gleixner 已提交
6662

6663
	mutex_init(&event->mmap_mutex);
6664

6665
	atomic_long_set(&event->refcount, 1);
6666 6667 6668 6669 6670
	event->cpu		= cpu;
	event->attr		= *attr;
	event->group_leader	= group_leader;
	event->pmu		= NULL;
	event->oncpu		= -1;
6671

6672
	event->parent		= parent_event;
6673

6674
	event->ns		= get_pid_ns(task_active_pid_ns(current));
6675
	event->id		= atomic64_inc_return(&perf_event_id);
6676

6677
	event->state		= PERF_EVENT_STATE_INACTIVE;
6678

6679 6680
	if (task) {
		event->attach_state = PERF_ATTACH_TASK;
6681 6682 6683

		if (attr->type == PERF_TYPE_TRACEPOINT)
			event->hw.tp_target = task;
6684 6685 6686 6687
#ifdef CONFIG_HAVE_HW_BREAKPOINT
		/*
		 * hw_breakpoint is a bit difficult here..
		 */
6688
		else if (attr->type == PERF_TYPE_BREAKPOINT)
6689 6690 6691 6692
			event->hw.bp_target = task;
#endif
	}

6693
	if (!overflow_handler && parent_event) {
6694
		overflow_handler = parent_event->overflow_handler;
6695 6696
		context = parent_event->overflow_handler_context;
	}
6697

6698
	event->overflow_handler	= overflow_handler;
6699
	event->overflow_handler_context = context;
6700

J
Jiri Olsa 已提交
6701
	perf_event__state_init(event);
6702

6703
	pmu = NULL;
6704

6705
	hwc = &event->hw;
6706
	hwc->sample_period = attr->sample_period;
6707
	if (attr->freq && attr->sample_freq)
6708
		hwc->sample_period = 1;
6709
	hwc->last_period = hwc->sample_period;
6710

6711
	local64_set(&hwc->period_left, hwc->sample_period);
6712

6713
	/*
6714
	 * we currently do not support PERF_FORMAT_GROUP on inherited events
6715
	 */
6716
	if (attr->inherit && (attr->read_format & PERF_FORMAT_GROUP))
6717
		goto err_ns;
6718

6719
	pmu = perf_init_event(event);
6720
	if (!pmu)
6721 6722
		goto err_ns;
	else if (IS_ERR(pmu)) {
6723
		err = PTR_ERR(pmu);
6724
		goto err_ns;
I
Ingo Molnar 已提交
6725
	}
6726

6727
	if (!event->parent) {
6728 6729
		if (event->attr.sample_type & PERF_SAMPLE_CALLCHAIN) {
			err = get_callchain_buffers();
6730 6731
			if (err)
				goto err_pmu;
6732
		}
6733
	}
6734

6735
	return event;
6736 6737 6738 6739 6740 6741 6742 6743 6744 6745

err_pmu:
	if (event->destroy)
		event->destroy(event);
err_ns:
	if (event->ns)
		put_pid_ns(event->ns);
	kfree(event);

	return ERR_PTR(err);
T
Thomas Gleixner 已提交
6746 6747
}

6748 6749
static int perf_copy_attr(struct perf_event_attr __user *uattr,
			  struct perf_event_attr *attr)
6750 6751
{
	u32 size;
6752
	int ret;
6753 6754 6755 6756 6757 6758 6759 6760 6761 6762 6763 6764 6765 6766 6767 6768 6769 6770 6771 6772 6773 6774 6775 6776

	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,
6777 6778 6779
	 * 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.
6780 6781
	 */
	if (size > sizeof(*attr)) {
6782 6783 6784
		unsigned char __user *addr;
		unsigned char __user *end;
		unsigned char val;
6785

6786 6787
		addr = (void __user *)uattr + sizeof(*attr);
		end  = (void __user *)uattr + size;
6788

6789
		for (; addr < end; addr++) {
6790 6791 6792 6793 6794 6795
			ret = get_user(val, addr);
			if (ret)
				return ret;
			if (val)
				goto err_size;
		}
6796
		size = sizeof(*attr);
6797 6798 6799 6800 6801 6802
	}

	ret = copy_from_user(attr, uattr, size);
	if (ret)
		return -EFAULT;

6803 6804 6805 6806
	/* disabled for now */
	if (attr->mmap2)
		return -EINVAL;

6807
	if (attr->__reserved_1)
6808 6809 6810 6811 6812 6813 6814 6815
		return -EINVAL;

	if (attr->sample_type & ~(PERF_SAMPLE_MAX-1))
		return -EINVAL;

	if (attr->read_format & ~(PERF_FORMAT_MAX-1))
		return -EINVAL;

6816 6817 6818 6819 6820 6821 6822 6823 6824 6825 6826 6827 6828 6829 6830 6831 6832 6833 6834 6835 6836 6837 6838 6839 6840 6841 6842 6843
	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;
		}
6844 6845
		/* privileged levels capture (kernel, hv): check permissions */
		if ((mask & PERF_SAMPLE_BRANCH_PERM_PLM)
6846 6847
		    && perf_paranoid_kernel() && !capable(CAP_SYS_ADMIN))
			return -EACCES;
6848
	}
6849

6850
	if (attr->sample_type & PERF_SAMPLE_REGS_USER) {
6851
		ret = perf_reg_validate(attr->sample_regs_user);
6852 6853 6854 6855 6856 6857 6858 6859 6860 6861 6862 6863 6864 6865 6866 6867 6868 6869
		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;
	}
6870

6871 6872 6873 6874 6875 6876 6877 6878 6879
out:
	return ret;

err_size:
	put_user(sizeof(*attr), &uattr->size);
	ret = -E2BIG;
	goto out;
}

6880 6881
static int
perf_event_set_output(struct perf_event *event, struct perf_event *output_event)
6882
{
6883
	struct ring_buffer *rb = NULL, *old_rb = NULL;
6884 6885
	int ret = -EINVAL;

6886
	if (!output_event)
6887 6888
		goto set;

6889 6890
	/* don't allow circular references */
	if (event == output_event)
6891 6892
		goto out;

6893 6894 6895 6896 6897 6898 6899
	/*
	 * Don't allow cross-cpu buffers
	 */
	if (output_event->cpu != event->cpu)
		goto out;

	/*
6900
	 * If its not a per-cpu rb, it must be the same task.
6901 6902 6903 6904
	 */
	if (output_event->cpu == -1 && output_event->ctx != event->ctx)
		goto out;

6905
set:
6906
	mutex_lock(&event->mmap_mutex);
6907 6908 6909
	/* Can't redirect output if we've got an active mmap() */
	if (atomic_read(&event->mmap_count))
		goto unlock;
6910

6911 6912
	old_rb = event->rb;

6913
	if (output_event) {
6914 6915 6916
		/* get the rb we want to redirect to */
		rb = ring_buffer_get(output_event);
		if (!rb)
6917
			goto unlock;
6918 6919
	}

6920 6921
	if (old_rb)
		ring_buffer_detach(event, old_rb);
6922 6923 6924 6925 6926 6927 6928 6929 6930 6931 6932 6933 6934 6935 6936 6937

	if (rb)
		ring_buffer_attach(event, rb);

	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);
	}

6938
	ret = 0;
6939 6940 6941
unlock:
	mutex_unlock(&event->mmap_mutex);

6942 6943 6944 6945
out:
	return ret;
}

T
Thomas Gleixner 已提交
6946
/**
6947
 * sys_perf_event_open - open a performance event, associate it to a task/cpu
I
Ingo Molnar 已提交
6948
 *
6949
 * @attr_uptr:	event_id type attributes for monitoring/sampling
T
Thomas Gleixner 已提交
6950
 * @pid:		target pid
I
Ingo Molnar 已提交
6951
 * @cpu:		target cpu
6952
 * @group_fd:		group leader event fd
T
Thomas Gleixner 已提交
6953
 */
6954 6955
SYSCALL_DEFINE5(perf_event_open,
		struct perf_event_attr __user *, attr_uptr,
6956
		pid_t, pid, int, cpu, int, group_fd, unsigned long, flags)
T
Thomas Gleixner 已提交
6957
{
6958 6959
	struct perf_event *group_leader = NULL, *output_event = NULL;
	struct perf_event *event, *sibling;
6960 6961 6962
	struct perf_event_attr attr;
	struct perf_event_context *ctx;
	struct file *event_file = NULL;
6963
	struct fd group = {NULL, 0};
M
Matt Helsley 已提交
6964
	struct task_struct *task = NULL;
6965
	struct pmu *pmu;
6966
	int event_fd;
6967
	int move_group = 0;
6968
	int err;
T
Thomas Gleixner 已提交
6969

6970
	/* for future expandability... */
S
Stephane Eranian 已提交
6971
	if (flags & ~PERF_FLAG_ALL)
6972 6973
		return -EINVAL;

6974 6975 6976
	err = perf_copy_attr(attr_uptr, &attr);
	if (err)
		return err;
6977

6978 6979 6980 6981 6982
	if (!attr.exclude_kernel) {
		if (perf_paranoid_kernel() && !capable(CAP_SYS_ADMIN))
			return -EACCES;
	}

6983
	if (attr.freq) {
6984
		if (attr.sample_freq > sysctl_perf_event_sample_rate)
6985 6986 6987
			return -EINVAL;
	}

S
Stephane Eranian 已提交
6988 6989 6990 6991 6992 6993 6994 6995 6996
	/*
	 * 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;

6997
	event_fd = get_unused_fd();
6998 6999 7000
	if (event_fd < 0)
		return event_fd;

7001
	if (group_fd != -1) {
7002 7003
		err = perf_fget_light(group_fd, &group);
		if (err)
7004
			goto err_fd;
7005
		group_leader = group.file->private_data;
7006 7007 7008 7009 7010 7011
		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
7012
	if (pid != -1 && !(flags & PERF_FLAG_PID_CGROUP)) {
7013 7014 7015 7016 7017 7018 7019
		task = find_lively_task_by_vpid(pid);
		if (IS_ERR(task)) {
			err = PTR_ERR(task);
			goto err_group_fd;
		}
	}

7020 7021
	get_online_cpus();

7022 7023
	event = perf_event_alloc(&attr, cpu, task, group_leader, NULL,
				 NULL, NULL);
7024 7025
	if (IS_ERR(event)) {
		err = PTR_ERR(event);
7026
		goto err_task;
7027 7028
	}

S
Stephane Eranian 已提交
7029 7030
	if (flags & PERF_FLAG_PID_CGROUP) {
		err = perf_cgroup_connect(pid, event, &attr, group_leader);
7031 7032 7033 7034
		if (err) {
			__free_event(event);
			goto err_task;
		}
S
Stephane Eranian 已提交
7035 7036
	}

7037 7038
	account_event(event);

7039 7040 7041 7042 7043
	/*
	 * Special case software events and allow them to be part of
	 * any hardware group.
	 */
	pmu = event->pmu;
7044 7045 7046 7047 7048 7049 7050 7051 7052 7053 7054 7055 7056 7057 7058 7059 7060 7061 7062 7063 7064 7065 7066

	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;
		}
	}
7067 7068 7069 7070

	/*
	 * Get the target context (task or percpu):
	 */
7071
	ctx = find_get_context(pmu, task, event->cpu);
7072 7073
	if (IS_ERR(ctx)) {
		err = PTR_ERR(ctx);
7074
		goto err_alloc;
7075 7076
	}

7077 7078 7079 7080 7081
	if (task) {
		put_task_struct(task);
		task = NULL;
	}

I
Ingo Molnar 已提交
7082
	/*
7083
	 * Look up the group leader (we will attach this event to it):
7084
	 */
7085
	if (group_leader) {
7086
		err = -EINVAL;
7087 7088

		/*
I
Ingo Molnar 已提交
7089 7090 7091 7092
		 * Do not allow a recursive hierarchy (this new sibling
		 * becoming part of another group-sibling):
		 */
		if (group_leader->group_leader != group_leader)
7093
			goto err_context;
I
Ingo Molnar 已提交
7094 7095 7096
		/*
		 * Do not allow to attach to a group in a different
		 * task or CPU context:
7097
		 */
7098 7099 7100 7101 7102 7103 7104 7105
		if (move_group) {
			if (group_leader->ctx->type != ctx->type)
				goto err_context;
		} else {
			if (group_leader->ctx != ctx)
				goto err_context;
		}

7106 7107 7108
		/*
		 * Only a group leader can be exclusive or pinned
		 */
7109
		if (attr.exclusive || attr.pinned)
7110
			goto err_context;
7111 7112 7113 7114 7115
	}

	if (output_event) {
		err = perf_event_set_output(event, output_event);
		if (err)
7116
			goto err_context;
7117
	}
T
Thomas Gleixner 已提交
7118

7119 7120 7121
	event_file = anon_inode_getfile("[perf_event]", &perf_fops, event, O_RDWR);
	if (IS_ERR(event_file)) {
		err = PTR_ERR(event_file);
7122
		goto err_context;
7123
	}
7124

7125 7126 7127 7128
	if (move_group) {
		struct perf_event_context *gctx = group_leader->ctx;

		mutex_lock(&gctx->mutex);
7129
		perf_remove_from_context(group_leader);
J
Jiri Olsa 已提交
7130 7131 7132 7133 7134 7135 7136

		/*
		 * 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);
7137 7138
		list_for_each_entry(sibling, &group_leader->sibling_list,
				    group_entry) {
7139
			perf_remove_from_context(sibling);
J
Jiri Olsa 已提交
7140
			perf_event__state_init(sibling);
7141 7142 7143 7144
			put_ctx(gctx);
		}
		mutex_unlock(&gctx->mutex);
		put_ctx(gctx);
7145
	}
7146

7147
	WARN_ON_ONCE(ctx->parent_ctx);
7148
	mutex_lock(&ctx->mutex);
7149 7150

	if (move_group) {
7151
		synchronize_rcu();
7152
		perf_install_in_context(ctx, group_leader, event->cpu);
7153 7154 7155
		get_ctx(ctx);
		list_for_each_entry(sibling, &group_leader->sibling_list,
				    group_entry) {
7156
			perf_install_in_context(ctx, sibling, event->cpu);
7157 7158 7159 7160
			get_ctx(ctx);
		}
	}

7161
	perf_install_in_context(ctx, event, event->cpu);
7162
	perf_unpin_context(ctx);
7163
	mutex_unlock(&ctx->mutex);
7164

7165 7166
	put_online_cpus();

7167
	event->owner = current;
P
Peter Zijlstra 已提交
7168

7169 7170 7171
	mutex_lock(&current->perf_event_mutex);
	list_add_tail(&event->owner_entry, &current->perf_event_list);
	mutex_unlock(&current->perf_event_mutex);
7172

7173 7174 7175 7176
	/*
	 * Precalculate sample_data sizes
	 */
	perf_event__header_size(event);
7177
	perf_event__id_header_size(event);
7178

7179 7180 7181 7182 7183 7184
	/*
	 * 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().
	 */
7185
	fdput(group);
7186 7187
	fd_install(event_fd, event_file);
	return event_fd;
T
Thomas Gleixner 已提交
7188

7189
err_context:
7190
	perf_unpin_context(ctx);
7191
	put_ctx(ctx);
7192
err_alloc:
7193
	free_event(event);
P
Peter Zijlstra 已提交
7194
err_task:
7195
	put_online_cpus();
P
Peter Zijlstra 已提交
7196 7197
	if (task)
		put_task_struct(task);
7198
err_group_fd:
7199
	fdput(group);
7200 7201
err_fd:
	put_unused_fd(event_fd);
7202
	return err;
T
Thomas Gleixner 已提交
7203 7204
}

7205 7206 7207 7208 7209
/**
 * 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
7210
 * @task: task to profile (NULL for percpu)
7211 7212 7213
 */
struct perf_event *
perf_event_create_kernel_counter(struct perf_event_attr *attr, int cpu,
M
Matt Helsley 已提交
7214
				 struct task_struct *task,
7215 7216
				 perf_overflow_handler_t overflow_handler,
				 void *context)
7217 7218
{
	struct perf_event_context *ctx;
7219
	struct perf_event *event;
7220
	int err;
7221

7222 7223 7224
	/*
	 * Get the target context (task or percpu):
	 */
7225

7226 7227
	event = perf_event_alloc(attr, cpu, task, NULL, NULL,
				 overflow_handler, context);
7228 7229 7230 7231
	if (IS_ERR(event)) {
		err = PTR_ERR(event);
		goto err;
	}
7232

7233 7234
	account_event(event);

M
Matt Helsley 已提交
7235
	ctx = find_get_context(event->pmu, task, cpu);
7236 7237
	if (IS_ERR(ctx)) {
		err = PTR_ERR(ctx);
7238
		goto err_free;
7239
	}
7240 7241 7242 7243

	WARN_ON_ONCE(ctx->parent_ctx);
	mutex_lock(&ctx->mutex);
	perf_install_in_context(ctx, event, cpu);
7244
	perf_unpin_context(ctx);
7245 7246 7247 7248
	mutex_unlock(&ctx->mutex);

	return event;

7249 7250 7251
err_free:
	free_event(event);
err:
7252
	return ERR_PTR(err);
7253
}
7254
EXPORT_SYMBOL_GPL(perf_event_create_kernel_counter);
7255

7256 7257 7258 7259 7260 7261 7262 7263 7264 7265 7266 7267 7268 7269
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;

	mutex_lock(&src_ctx->mutex);
	list_for_each_entry_safe(event, tmp, &src_ctx->event_list,
				 event_entry) {
		perf_remove_from_context(event);
7270
		unaccount_event_cpu(event, src_cpu);
7271
		put_ctx(src_ctx);
7272
		list_add(&event->migrate_entry, &events);
7273 7274 7275 7276 7277 7278
	}
	mutex_unlock(&src_ctx->mutex);

	synchronize_rcu();

	mutex_lock(&dst_ctx->mutex);
7279 7280
	list_for_each_entry_safe(event, tmp, &events, migrate_entry) {
		list_del(&event->migrate_entry);
7281 7282
		if (event->state >= PERF_EVENT_STATE_OFF)
			event->state = PERF_EVENT_STATE_INACTIVE;
7283
		account_event_cpu(event, dst_cpu);
7284 7285 7286 7287 7288 7289 7290
		perf_install_in_context(dst_ctx, event, dst_cpu);
		get_ctx(dst_ctx);
	}
	mutex_unlock(&dst_ctx->mutex);
}
EXPORT_SYMBOL_GPL(perf_pmu_migrate_context);

7291
static void sync_child_event(struct perf_event *child_event,
7292
			       struct task_struct *child)
7293
{
7294
	struct perf_event *parent_event = child_event->parent;
7295
	u64 child_val;
7296

7297 7298
	if (child_event->attr.inherit_stat)
		perf_event_read_event(child_event, child);
7299

P
Peter Zijlstra 已提交
7300
	child_val = perf_event_count(child_event);
7301 7302 7303 7304

	/*
	 * Add back the child's count to the parent's count:
	 */
7305
	atomic64_add(child_val, &parent_event->child_count);
7306 7307 7308 7309
	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);
7310 7311

	/*
7312
	 * Remove this event from the parent's list
7313
	 */
7314 7315 7316 7317
	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);
7318 7319

	/*
7320
	 * Release the parent event, if this was the last
7321 7322
	 * reference to it.
	 */
7323
	put_event(parent_event);
7324 7325
}

7326
static void
7327 7328
__perf_event_exit_task(struct perf_event *child_event,
			 struct perf_event_context *child_ctx,
7329
			 struct task_struct *child)
7330
{
7331 7332 7333 7334 7335
	if (child_event->parent) {
		raw_spin_lock_irq(&child_ctx->lock);
		perf_group_detach(child_event);
		raw_spin_unlock_irq(&child_ctx->lock);
	}
7336

7337
	perf_remove_from_context(child_event);
7338

7339
	/*
7340
	 * It can happen that the parent exits first, and has events
7341
	 * that are still around due to the child reference. These
7342
	 * events need to be zapped.
7343
	 */
7344
	if (child_event->parent) {
7345 7346
		sync_child_event(child_event, child);
		free_event(child_event);
7347
	}
7348 7349
}

P
Peter Zijlstra 已提交
7350
static void perf_event_exit_task_context(struct task_struct *child, int ctxn)
7351
{
7352 7353
	struct perf_event *child_event, *tmp;
	struct perf_event_context *child_ctx;
7354
	unsigned long flags;
7355

P
Peter Zijlstra 已提交
7356
	if (likely(!child->perf_event_ctxp[ctxn])) {
7357
		perf_event_task(child, NULL, 0);
7358
		return;
P
Peter Zijlstra 已提交
7359
	}
7360

7361
	local_irq_save(flags);
7362 7363 7364 7365 7366 7367
	/*
	 * We can't reschedule here because interrupts are disabled,
	 * and either child is current or it is a task that can't be
	 * scheduled, so we are now safe from rescheduling changing
	 * our context.
	 */
7368
	child_ctx = rcu_dereference_raw(child->perf_event_ctxp[ctxn]);
7369 7370 7371

	/*
	 * Take the context lock here so that if find_get_context is
7372
	 * reading child->perf_event_ctxp, we wait until it has
7373 7374
	 * incremented the context's refcount before we do put_ctx below.
	 */
7375
	raw_spin_lock(&child_ctx->lock);
7376
	task_ctx_sched_out(child_ctx);
P
Peter Zijlstra 已提交
7377
	child->perf_event_ctxp[ctxn] = NULL;
7378 7379 7380
	/*
	 * If this context is a clone; unclone it so it can't get
	 * swapped to another process while we're removing all
7381
	 * the events from it.
7382 7383
	 */
	unclone_ctx(child_ctx);
7384
	update_context_time(child_ctx);
7385
	raw_spin_unlock_irqrestore(&child_ctx->lock, flags);
P
Peter Zijlstra 已提交
7386 7387

	/*
7388 7389 7390
	 * 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
7391
	 */
7392
	perf_event_task(child, child_ctx, 0);
7393

7394 7395 7396
	/*
	 * We can recurse on the same lock type through:
	 *
7397 7398
	 *   __perf_event_exit_task()
	 *     sync_child_event()
7399 7400
	 *       put_event()
	 *         mutex_lock(&ctx->mutex)
7401 7402 7403
	 *
	 * But since its the parent context it won't be the same instance.
	 */
7404
	mutex_lock(&child_ctx->mutex);
7405

7406
again:
7407 7408 7409 7410 7411
	list_for_each_entry_safe(child_event, tmp, &child_ctx->pinned_groups,
				 group_entry)
		__perf_event_exit_task(child_event, child_ctx, child);

	list_for_each_entry_safe(child_event, tmp, &child_ctx->flexible_groups,
7412
				 group_entry)
7413
		__perf_event_exit_task(child_event, child_ctx, child);
7414 7415

	/*
7416
	 * If the last event was a group event, it will have appended all
7417 7418 7419
	 * its siblings to the list, but we obtained 'tmp' before that which
	 * will still point to the list head terminating the iteration.
	 */
7420 7421
	if (!list_empty(&child_ctx->pinned_groups) ||
	    !list_empty(&child_ctx->flexible_groups))
7422
		goto again;
7423 7424 7425 7426

	mutex_unlock(&child_ctx->mutex);

	put_ctx(child_ctx);
7427 7428
}

P
Peter Zijlstra 已提交
7429 7430 7431 7432 7433
/*
 * 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
7434
	struct perf_event *event, *tmp;
P
Peter Zijlstra 已提交
7435 7436
	int ctxn;

P
Peter Zijlstra 已提交
7437 7438 7439 7440 7441 7442 7443 7444 7445 7446 7447 7448 7449 7450 7451
	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.
		 */
		smp_wmb();
		event->owner = NULL;
	}
	mutex_unlock(&child->perf_event_mutex);

P
Peter Zijlstra 已提交
7452 7453 7454 7455
	for_each_task_context_nr(ctxn)
		perf_event_exit_task_context(child, ctxn);
}

7456 7457 7458 7459 7460 7461 7462 7463 7464 7465 7466 7467
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);

7468
	put_event(parent);
7469

7470
	perf_group_detach(event);
7471 7472 7473 7474
	list_del_event(event, ctx);
	free_event(event);
}

7475 7476
/*
 * free an unexposed, unused context as created by inheritance by
P
Peter Zijlstra 已提交
7477
 * perf_event_init_task below, used by fork() in case of fail.
7478
 */
7479
void perf_event_free_task(struct task_struct *task)
7480
{
P
Peter Zijlstra 已提交
7481
	struct perf_event_context *ctx;
7482
	struct perf_event *event, *tmp;
P
Peter Zijlstra 已提交
7483
	int ctxn;
7484

P
Peter Zijlstra 已提交
7485 7486 7487 7488
	for_each_task_context_nr(ctxn) {
		ctx = task->perf_event_ctxp[ctxn];
		if (!ctx)
			continue;
7489

P
Peter Zijlstra 已提交
7490
		mutex_lock(&ctx->mutex);
7491
again:
P
Peter Zijlstra 已提交
7492 7493 7494
		list_for_each_entry_safe(event, tmp, &ctx->pinned_groups,
				group_entry)
			perf_free_event(event, ctx);
7495

P
Peter Zijlstra 已提交
7496 7497 7498
		list_for_each_entry_safe(event, tmp, &ctx->flexible_groups,
				group_entry)
			perf_free_event(event, ctx);
7499

P
Peter Zijlstra 已提交
7500 7501 7502
		if (!list_empty(&ctx->pinned_groups) ||
				!list_empty(&ctx->flexible_groups))
			goto again;
7503

P
Peter Zijlstra 已提交
7504
		mutex_unlock(&ctx->mutex);
7505

P
Peter Zijlstra 已提交
7506 7507
		put_ctx(ctx);
	}
7508 7509
}

7510 7511 7512 7513 7514 7515 7516 7517
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]);
}

P
Peter Zijlstra 已提交
7518 7519 7520 7521 7522 7523 7524 7525 7526 7527 7528 7529
/*
 * 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)
{
	struct perf_event *child_event;
7530
	unsigned long flags;
P
Peter Zijlstra 已提交
7531 7532 7533 7534 7535 7536 7537 7538 7539 7540 7541 7542

	/*
	 * 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,
7543
					   child,
P
Peter Zijlstra 已提交
7544
					   group_leader, parent_event,
7545
				           NULL, NULL);
P
Peter Zijlstra 已提交
7546 7547
	if (IS_ERR(child_event))
		return child_event;
7548 7549 7550 7551 7552 7553

	if (!atomic_long_inc_not_zero(&parent_event->refcount)) {
		free_event(child_event);
		return NULL;
	}

P
Peter Zijlstra 已提交
7554 7555 7556 7557 7558 7559 7560 7561 7562 7563 7564 7565 7566 7567 7568 7569 7570 7571 7572 7573 7574 7575 7576 7577
	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.
	 */
	if (parent_event->state >= PERF_EVENT_STATE_INACTIVE)
		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;
7578 7579
	child_event->overflow_handler_context
		= parent_event->overflow_handler_context;
P
Peter Zijlstra 已提交
7580

7581 7582 7583 7584
	/*
	 * Precalculate sample_data sizes
	 */
	perf_event__header_size(child_event);
7585
	perf_event__id_header_size(child_event);
7586

P
Peter Zijlstra 已提交
7587 7588 7589
	/*
	 * Link it up in the child's context:
	 */
7590
	raw_spin_lock_irqsave(&child_ctx->lock, flags);
P
Peter Zijlstra 已提交
7591
	add_event_to_ctx(child_event, child_ctx);
7592
	raw_spin_unlock_irqrestore(&child_ctx->lock, flags);
P
Peter Zijlstra 已提交
7593 7594 7595 7596 7597 7598 7599 7600 7601 7602 7603 7604 7605 7606 7607 7608 7609 7610 7611 7612 7613 7614 7615 7616 7617 7618 7619 7620 7621 7622 7623 7624 7625

	/*
	 * Link this into the parent event's child list
	 */
	WARN_ON_ONCE(parent_event->ctx->parent_ctx);
	mutex_lock(&parent_event->child_mutex);
	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;
7626 7627 7628 7629 7630
}

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
7631
		   struct task_struct *child, int ctxn,
7632 7633 7634
		   int *inherited_all)
{
	int ret;
P
Peter Zijlstra 已提交
7635
	struct perf_event_context *child_ctx;
7636 7637 7638 7639

	if (!event->attr.inherit) {
		*inherited_all = 0;
		return 0;
7640 7641
	}

7642
	child_ctx = child->perf_event_ctxp[ctxn];
7643 7644 7645 7646 7647 7648 7649
	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.
		 */
7650

7651
		child_ctx = alloc_perf_context(parent_ctx->pmu, child);
7652 7653
		if (!child_ctx)
			return -ENOMEM;
7654

P
Peter Zijlstra 已提交
7655
		child->perf_event_ctxp[ctxn] = child_ctx;
7656 7657 7658 7659 7660 7661 7662 7663 7664
	}

	ret = inherit_group(event, parent, parent_ctx,
			    child, child_ctx);

	if (ret)
		*inherited_all = 0;

	return ret;
7665 7666
}

7667
/*
7668
 * Initialize the perf_event context in task_struct
7669
 */
P
Peter Zijlstra 已提交
7670
int perf_event_init_context(struct task_struct *child, int ctxn)
7671
{
7672
	struct perf_event_context *child_ctx, *parent_ctx;
7673 7674
	struct perf_event_context *cloned_ctx;
	struct perf_event *event;
7675
	struct task_struct *parent = current;
7676
	int inherited_all = 1;
7677
	unsigned long flags;
7678
	int ret = 0;
7679

P
Peter Zijlstra 已提交
7680
	if (likely(!parent->perf_event_ctxp[ctxn]))
7681 7682
		return 0;

7683
	/*
7684 7685
	 * If the parent's context is a clone, pin it so it won't get
	 * swapped under us.
7686
	 */
P
Peter Zijlstra 已提交
7687
	parent_ctx = perf_pin_task_context(parent, ctxn);
7688

7689 7690 7691 7692 7693 7694 7695
	/*
	 * 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.
	 */

7696 7697 7698 7699
	/*
	 * Lock the parent list. No need to lock the child - not PID
	 * hashed yet and not running, so nobody can access it.
	 */
7700
	mutex_lock(&parent_ctx->mutex);
7701 7702 7703 7704 7705

	/*
	 * We dont have to disable NMIs - we are only looking at
	 * the list, not manipulating it:
	 */
7706
	list_for_each_entry(event, &parent_ctx->pinned_groups, group_entry) {
P
Peter Zijlstra 已提交
7707 7708
		ret = inherit_task_group(event, parent, parent_ctx,
					 child, ctxn, &inherited_all);
7709 7710 7711
		if (ret)
			break;
	}
7712

7713 7714 7715 7716 7717 7718 7719 7720 7721
	/*
	 * 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);

7722
	list_for_each_entry(event, &parent_ctx->flexible_groups, group_entry) {
P
Peter Zijlstra 已提交
7723 7724
		ret = inherit_task_group(event, parent, parent_ctx,
					 child, ctxn, &inherited_all);
7725
		if (ret)
7726
			break;
7727 7728
	}

7729 7730 7731
	raw_spin_lock_irqsave(&parent_ctx->lock, flags);
	parent_ctx->rotate_disable = 0;

P
Peter Zijlstra 已提交
7732
	child_ctx = child->perf_event_ctxp[ctxn];
7733

7734
	if (child_ctx && inherited_all) {
7735 7736 7737
		/*
		 * 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
7738 7739 7740
		 *
		 * Note that if the parent is a clone, the holding of
		 * parent_ctx->lock avoids it from being uncloned.
7741
		 */
P
Peter Zijlstra 已提交
7742
		cloned_ctx = parent_ctx->parent_ctx;
7743 7744
		if (cloned_ctx) {
			child_ctx->parent_ctx = cloned_ctx;
7745
			child_ctx->parent_gen = parent_ctx->parent_gen;
7746 7747 7748 7749 7750
		} else {
			child_ctx->parent_ctx = parent_ctx;
			child_ctx->parent_gen = parent_ctx->generation;
		}
		get_ctx(child_ctx->parent_ctx);
7751 7752
	}

P
Peter Zijlstra 已提交
7753
	raw_spin_unlock_irqrestore(&parent_ctx->lock, flags);
7754
	mutex_unlock(&parent_ctx->mutex);
7755

7756
	perf_unpin_context(parent_ctx);
7757
	put_ctx(parent_ctx);
7758

7759
	return ret;
7760 7761
}

P
Peter Zijlstra 已提交
7762 7763 7764 7765 7766 7767 7768
/*
 * Initialize the perf_event context in task_struct
 */
int perf_event_init_task(struct task_struct *child)
{
	int ctxn, ret;

7769 7770 7771 7772
	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
7773 7774 7775 7776 7777 7778 7779 7780 7781
	for_each_task_context_nr(ctxn) {
		ret = perf_event_init_context(child, ctxn);
		if (ret)
			return ret;
	}

	return 0;
}

7782 7783
static void __init perf_event_init_all_cpus(void)
{
7784
	struct swevent_htable *swhash;
7785 7786 7787
	int cpu;

	for_each_possible_cpu(cpu) {
7788 7789
		swhash = &per_cpu(swevent_htable, cpu);
		mutex_init(&swhash->hlist_mutex);
7790
		INIT_LIST_HEAD(&per_cpu(rotation_list, cpu));
7791 7792 7793
	}
}

7794
static void perf_event_init_cpu(int cpu)
T
Thomas Gleixner 已提交
7795
{
P
Peter Zijlstra 已提交
7796
	struct swevent_htable *swhash = &per_cpu(swevent_htable, cpu);
T
Thomas Gleixner 已提交
7797

7798
	mutex_lock(&swhash->hlist_mutex);
7799
	if (swhash->hlist_refcount > 0) {
7800 7801
		struct swevent_hlist *hlist;

7802 7803 7804
		hlist = kzalloc_node(sizeof(*hlist), GFP_KERNEL, cpu_to_node(cpu));
		WARN_ON(!hlist);
		rcu_assign_pointer(swhash->swevent_hlist, hlist);
7805
	}
7806
	mutex_unlock(&swhash->hlist_mutex);
T
Thomas Gleixner 已提交
7807 7808
}

P
Peter Zijlstra 已提交
7809
#if defined CONFIG_HOTPLUG_CPU || defined CONFIG_KEXEC
7810
static void perf_pmu_rotate_stop(struct pmu *pmu)
T
Thomas Gleixner 已提交
7811
{
7812 7813 7814 7815 7816 7817 7818
	struct perf_cpu_context *cpuctx = this_cpu_ptr(pmu->pmu_cpu_context);

	WARN_ON(!irqs_disabled());

	list_del_init(&cpuctx->rotation_list);
}

P
Peter Zijlstra 已提交
7819
static void __perf_event_exit_context(void *__info)
T
Thomas Gleixner 已提交
7820
{
P
Peter Zijlstra 已提交
7821
	struct perf_event_context *ctx = __info;
7822
	struct perf_event *event, *tmp;
T
Thomas Gleixner 已提交
7823

P
Peter Zijlstra 已提交
7824
	perf_pmu_rotate_stop(ctx->pmu);
7825

7826
	list_for_each_entry_safe(event, tmp, &ctx->pinned_groups, group_entry)
7827
		__perf_remove_from_context(event);
7828
	list_for_each_entry_safe(event, tmp, &ctx->flexible_groups, group_entry)
7829
		__perf_remove_from_context(event);
T
Thomas Gleixner 已提交
7830
}
P
Peter Zijlstra 已提交
7831 7832 7833 7834 7835 7836 7837 7838 7839

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) {
7840
		ctx = &per_cpu_ptr(pmu->pmu_cpu_context, cpu)->ctx;
P
Peter Zijlstra 已提交
7841 7842 7843 7844 7845 7846 7847 7848

		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);
}

7849
static void perf_event_exit_cpu(int cpu)
T
Thomas Gleixner 已提交
7850
{
7851
	struct swevent_htable *swhash = &per_cpu(swevent_htable, cpu);
7852

7853 7854 7855
	mutex_lock(&swhash->hlist_mutex);
	swevent_hlist_release(swhash);
	mutex_unlock(&swhash->hlist_mutex);
7856

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7857
	perf_event_exit_cpu_context(cpu);
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7858 7859
}
#else
7860
static inline void perf_event_exit_cpu(int cpu) { }
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#endif

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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,
};

7883
static int
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perf_cpu_notify(struct notifier_block *self, unsigned long action, void *hcpu)
{
	unsigned int cpu = (long)hcpu;

7888
	switch (action & ~CPU_TASKS_FROZEN) {
T
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	case CPU_UP_PREPARE:
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7891
	case CPU_DOWN_FAILED:
7892
		perf_event_init_cpu(cpu);
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		break;

P
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7895
	case CPU_UP_CANCELED:
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7896
	case CPU_DOWN_PREPARE:
7897
		perf_event_exit_cpu(cpu);
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		break;
	default:
		break;
	}

	return NOTIFY_OK;
}

7906
void __init perf_event_init(void)
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{
7908 7909
	int ret;

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7910 7911
	idr_init(&pmu_idr);

7912
	perf_event_init_all_cpus();
7913
	init_srcu_struct(&pmus_srcu);
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	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);
7917 7918
	perf_tp_register();
	perf_cpu_notifier(perf_cpu_notify);
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	register_reboot_notifier(&perf_reboot_notifier);
7920 7921 7922

	ret = init_hw_breakpoint();
	WARN(ret, "hw_breakpoint initialization failed with: %d", ret);
7923 7924 7925

	/* do not patch jump label more than once per second */
	jump_label_rate_limit(&perf_sched_events, HZ);
7926 7927 7928 7929 7930 7931 7932

	/*
	 * 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);
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}
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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
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#ifdef CONFIG_CGROUP_PERF
7964 7965
static struct cgroup_subsys_state *
perf_cgroup_css_alloc(struct cgroup_subsys_state *parent_css)
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{
	struct perf_cgroup *jc;

7969
	jc = kzalloc(sizeof(*jc), GFP_KERNEL);
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	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;
}

7982
static void perf_cgroup_css_free(struct cgroup_subsys_state *css)
S
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7983
{
7984 7985
	struct perf_cgroup *jc = container_of(css, struct perf_cgroup, css);

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	free_percpu(jc->info);
	kfree(jc);
}

static int __perf_cgroup_move(void *info)
{
	struct task_struct *task = info;
	perf_cgroup_switch(task, PERF_CGROUP_SWOUT | PERF_CGROUP_SWIN);
	return 0;
}

7997 7998
static void perf_cgroup_attach(struct cgroup_subsys_state *css,
			       struct cgroup_taskset *tset)
S
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7999
{
8000 8001
	struct task_struct *task;

8002
	cgroup_taskset_for_each(task, css, tset)
8003
		task_function_call(task, __perf_cgroup_move, task);
S
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}

8006 8007
static void perf_cgroup_exit(struct cgroup_subsys_state *css,
			     struct cgroup_subsys_state *old_css,
8008
			     struct task_struct *task)
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{
	/*
	 * cgroup_exit() is called in the copy_process() failure path.
	 * Ignore this case since the task hasn't ran yet, this avoids
	 * trying to poke a half freed task state from generic code.
	 */
	if (!(task->flags & PF_EXITING))
		return;

8018
	task_function_call(task, __perf_cgroup_move, task);
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}

struct cgroup_subsys perf_subsys = {
8022 8023
	.name		= "perf_event",
	.subsys_id	= perf_subsys_id,
8024 8025
	.css_alloc	= perf_cgroup_css_alloc,
	.css_free	= perf_cgroup_css_free,
8026
	.exit		= perf_cgroup_exit,
8027
	.attach		= perf_cgroup_attach,
S
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};
#endif /* CONFIG_CGROUP_PERF */