2 * Performance events core code:
4 * Copyright (C) 2008 Thomas Gleixner <tglx@linutronix.de>
5 * Copyright (C) 2008-2011 Red Hat, Inc., Ingo Molnar
6 * Copyright (C) 2008-2011 Red Hat, Inc., Peter Zijlstra
7 * Copyright © 2009 Paul Mackerras, IBM Corp. <paulus@au1.ibm.com>
9 * For licensing details see kernel-base/COPYING
14 #include <linux/cpu.h>
15 #include <linux/smp.h>
16 #include <linux/idr.h>
17 #include <linux/file.h>
18 #include <linux/poll.h>
19 #include <linux/slab.h>
20 #include <linux/hash.h>
21 #include <linux/tick.h>
22 #include <linux/sysfs.h>
23 #include <linux/dcache.h>
24 #include <linux/percpu.h>
25 #include <linux/ptrace.h>
26 #include <linux/reboot.h>
27 #include <linux/vmstat.h>
28 #include <linux/device.h>
29 #include <linux/export.h>
30 #include <linux/vmalloc.h>
31 #include <linux/hardirq.h>
32 #include <linux/rculist.h>
33 #include <linux/uaccess.h>
34 #include <linux/syscalls.h>
35 #include <linux/anon_inodes.h>
36 #include <linux/kernel_stat.h>
37 #include <linux/cgroup.h>
38 #include <linux/perf_event.h>
39 #include <linux/trace_events.h>
40 #include <linux/hw_breakpoint.h>
41 #include <linux/mm_types.h>
42 #include <linux/module.h>
43 #include <linux/mman.h>
44 #include <linux/compat.h>
45 #include <linux/bpf.h>
46 #include <linux/filter.h>
50 #include <asm/irq_regs.h>
52 typedef int (*remote_function_f)(void *);
54 struct remote_function_call {
55 struct task_struct *p;
56 remote_function_f func;
61 static void remote_function(void *data)
63 struct remote_function_call *tfc = data;
64 struct task_struct *p = tfc->p;
68 if (task_cpu(p) != smp_processor_id() || !task_curr(p))
72 tfc->ret = tfc->func(tfc->info);
76 * task_function_call - call a function on the cpu on which a task runs
77 * @p: the task to evaluate
78 * @func: the function to be called
79 * @info: the function call argument
81 * Calls the function @func when the task is currently running. This might
82 * be on the current CPU, which just calls the function directly
84 * returns: @func return value, or
85 * -ESRCH - when the process isn't running
86 * -EAGAIN - when the process moved away
89 task_function_call(struct task_struct *p, remote_function_f func, void *info)
91 struct remote_function_call data = {
95 .ret = -ESRCH, /* No such (running) process */
99 smp_call_function_single(task_cpu(p), remote_function, &data, 1);
105 * cpu_function_call - call a function on the cpu
106 * @func: the function to be called
107 * @info: the function call argument
109 * Calls the function @func on the remote cpu.
111 * returns: @func return value or -ENXIO when the cpu is offline
113 static int cpu_function_call(int cpu, remote_function_f func, void *info)
115 struct remote_function_call data = {
119 .ret = -ENXIO, /* No such CPU */
122 smp_call_function_single(cpu, remote_function, &data, 1);
127 static inline struct perf_cpu_context *
128 __get_cpu_context(struct perf_event_context *ctx)
130 return this_cpu_ptr(ctx->pmu->pmu_cpu_context);
133 static void perf_ctx_lock(struct perf_cpu_context *cpuctx,
134 struct perf_event_context *ctx)
136 raw_spin_lock(&cpuctx->ctx.lock);
138 raw_spin_lock(&ctx->lock);
141 static void perf_ctx_unlock(struct perf_cpu_context *cpuctx,
142 struct perf_event_context *ctx)
145 raw_spin_unlock(&ctx->lock);
146 raw_spin_unlock(&cpuctx->ctx.lock);
149 #define TASK_TOMBSTONE ((void *)-1L)
151 static bool is_kernel_event(struct perf_event *event)
153 return READ_ONCE(event->owner) == TASK_TOMBSTONE;
157 * On task ctx scheduling...
159 * When !ctx->nr_events a task context will not be scheduled. This means
160 * we can disable the scheduler hooks (for performance) without leaving
161 * pending task ctx state.
163 * This however results in two special cases:
165 * - removing the last event from a task ctx; this is relatively straight
166 * forward and is done in __perf_remove_from_context.
168 * - adding the first event to a task ctx; this is tricky because we cannot
169 * rely on ctx->is_active and therefore cannot use event_function_call().
170 * See perf_install_in_context().
172 * This is because we need a ctx->lock serialized variable (ctx->is_active)
173 * to reliably determine if a particular task/context is scheduled in. The
174 * task_curr() use in task_function_call() is racy in that a remote context
175 * switch is not a single atomic operation.
177 * As is, the situation is 'safe' because we set rq->curr before we do the
178 * actual context switch. This means that task_curr() will fail early, but
179 * we'll continue spinning on ctx->is_active until we've passed
180 * perf_event_task_sched_out().
182 * Without this ctx->lock serialized variable we could have race where we find
183 * the task (and hence the context) would not be active while in fact they are.
185 * If ctx->nr_events, then ctx->is_active and cpuctx->task_ctx are set.
188 typedef void (*event_f)(struct perf_event *, struct perf_cpu_context *,
189 struct perf_event_context *, void *);
191 struct event_function_struct {
192 struct perf_event *event;
197 static int event_function(void *info)
199 struct event_function_struct *efs = info;
200 struct perf_event *event = efs->event;
201 struct perf_event_context *ctx = event->ctx;
202 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
203 struct perf_event_context *task_ctx = cpuctx->task_ctx;
206 WARN_ON_ONCE(!irqs_disabled());
208 perf_ctx_lock(cpuctx, task_ctx);
210 * Since we do the IPI call without holding ctx->lock things can have
211 * changed, double check we hit the task we set out to hit.
214 if (ctx->task != current) {
220 * We only use event_function_call() on established contexts,
221 * and event_function() is only ever called when active (or
222 * rather, we'll have bailed in task_function_call() or the
223 * above ctx->task != current test), therefore we must have
224 * ctx->is_active here.
226 WARN_ON_ONCE(!ctx->is_active);
228 * And since we have ctx->is_active, cpuctx->task_ctx must
231 WARN_ON_ONCE(task_ctx != ctx);
233 WARN_ON_ONCE(&cpuctx->ctx != ctx);
236 efs->func(event, cpuctx, ctx, efs->data);
238 perf_ctx_unlock(cpuctx, task_ctx);
243 static void event_function_local(struct perf_event *event, event_f func, void *data)
245 struct event_function_struct efs = {
251 int ret = event_function(&efs);
255 static void event_function_call(struct perf_event *event, event_f func, void *data)
257 struct perf_event_context *ctx = event->ctx;
258 struct task_struct *task = READ_ONCE(ctx->task); /* verified in event_function */
259 struct event_function_struct efs = {
265 if (!event->parent) {
267 * If this is a !child event, we must hold ctx::mutex to
268 * stabilize the the event->ctx relation. See
269 * perf_event_ctx_lock().
271 lockdep_assert_held(&ctx->mutex);
275 cpu_function_call(event->cpu, event_function, &efs);
280 if (task == TASK_TOMBSTONE)
283 if (!task_function_call(task, event_function, &efs))
286 raw_spin_lock_irq(&ctx->lock);
288 * Reload the task pointer, it might have been changed by
289 * a concurrent perf_event_context_sched_out().
292 if (task != TASK_TOMBSTONE) {
293 if (ctx->is_active) {
294 raw_spin_unlock_irq(&ctx->lock);
297 func(event, NULL, ctx, data);
299 raw_spin_unlock_irq(&ctx->lock);
302 #define PERF_FLAG_ALL (PERF_FLAG_FD_NO_GROUP |\
303 PERF_FLAG_FD_OUTPUT |\
304 PERF_FLAG_PID_CGROUP |\
305 PERF_FLAG_FD_CLOEXEC)
308 * branch priv levels that need permission checks
310 #define PERF_SAMPLE_BRANCH_PERM_PLM \
311 (PERF_SAMPLE_BRANCH_KERNEL |\
312 PERF_SAMPLE_BRANCH_HV)
315 EVENT_FLEXIBLE = 0x1,
317 EVENT_ALL = EVENT_FLEXIBLE | EVENT_PINNED,
321 * perf_sched_events : >0 events exist
322 * perf_cgroup_events: >0 per-cpu cgroup events exist on this cpu
324 struct static_key_deferred perf_sched_events __read_mostly;
325 static DEFINE_PER_CPU(atomic_t, perf_cgroup_events);
326 static DEFINE_PER_CPU(int, perf_sched_cb_usages);
328 static atomic_t nr_mmap_events __read_mostly;
329 static atomic_t nr_comm_events __read_mostly;
330 static atomic_t nr_task_events __read_mostly;
331 static atomic_t nr_freq_events __read_mostly;
332 static atomic_t nr_switch_events __read_mostly;
334 static LIST_HEAD(pmus);
335 static DEFINE_MUTEX(pmus_lock);
336 static struct srcu_struct pmus_srcu;
339 * perf event paranoia level:
340 * -1 - not paranoid at all
341 * 0 - disallow raw tracepoint access for unpriv
342 * 1 - disallow cpu events for unpriv
343 * 2 - disallow kernel profiling for unpriv
345 int sysctl_perf_event_paranoid __read_mostly = 1;
347 /* Minimum for 512 kiB + 1 user control page */
348 int sysctl_perf_event_mlock __read_mostly = 512 + (PAGE_SIZE / 1024); /* 'free' kiB per user */
351 * max perf event sample rate
353 #define DEFAULT_MAX_SAMPLE_RATE 100000
354 #define DEFAULT_SAMPLE_PERIOD_NS (NSEC_PER_SEC / DEFAULT_MAX_SAMPLE_RATE)
355 #define DEFAULT_CPU_TIME_MAX_PERCENT 25
357 int sysctl_perf_event_sample_rate __read_mostly = DEFAULT_MAX_SAMPLE_RATE;
359 static int max_samples_per_tick __read_mostly = DIV_ROUND_UP(DEFAULT_MAX_SAMPLE_RATE, HZ);
360 static int perf_sample_period_ns __read_mostly = DEFAULT_SAMPLE_PERIOD_NS;
362 static int perf_sample_allowed_ns __read_mostly =
363 DEFAULT_SAMPLE_PERIOD_NS * DEFAULT_CPU_TIME_MAX_PERCENT / 100;
365 static void update_perf_cpu_limits(void)
367 u64 tmp = perf_sample_period_ns;
369 tmp *= sysctl_perf_cpu_time_max_percent;
371 ACCESS_ONCE(perf_sample_allowed_ns) = tmp;
374 static int perf_rotate_context(struct perf_cpu_context *cpuctx);
376 int perf_proc_update_handler(struct ctl_table *table, int write,
377 void __user *buffer, size_t *lenp,
380 int ret = proc_dointvec_minmax(table, write, buffer, lenp, ppos);
385 max_samples_per_tick = DIV_ROUND_UP(sysctl_perf_event_sample_rate, HZ);
386 perf_sample_period_ns = NSEC_PER_SEC / sysctl_perf_event_sample_rate;
387 update_perf_cpu_limits();
392 int sysctl_perf_cpu_time_max_percent __read_mostly = DEFAULT_CPU_TIME_MAX_PERCENT;
394 int perf_cpu_time_max_percent_handler(struct ctl_table *table, int write,
395 void __user *buffer, size_t *lenp,
398 int ret = proc_dointvec(table, write, buffer, lenp, ppos);
403 update_perf_cpu_limits();
409 * perf samples are done in some very critical code paths (NMIs).
410 * If they take too much CPU time, the system can lock up and not
411 * get any real work done. This will drop the sample rate when
412 * we detect that events are taking too long.
414 #define NR_ACCUMULATED_SAMPLES 128
415 static DEFINE_PER_CPU(u64, running_sample_length);
417 static void perf_duration_warn(struct irq_work *w)
419 u64 allowed_ns = ACCESS_ONCE(perf_sample_allowed_ns);
420 u64 avg_local_sample_len;
421 u64 local_samples_len;
423 local_samples_len = __this_cpu_read(running_sample_length);
424 avg_local_sample_len = local_samples_len/NR_ACCUMULATED_SAMPLES;
426 printk_ratelimited(KERN_WARNING
427 "perf interrupt took too long (%lld > %lld), lowering "
428 "kernel.perf_event_max_sample_rate to %d\n",
429 avg_local_sample_len, allowed_ns >> 1,
430 sysctl_perf_event_sample_rate);
433 static DEFINE_IRQ_WORK(perf_duration_work, perf_duration_warn);
435 void perf_sample_event_took(u64 sample_len_ns)
437 u64 allowed_ns = ACCESS_ONCE(perf_sample_allowed_ns);
438 u64 avg_local_sample_len;
439 u64 local_samples_len;
444 /* decay the counter by 1 average sample */
445 local_samples_len = __this_cpu_read(running_sample_length);
446 local_samples_len -= local_samples_len/NR_ACCUMULATED_SAMPLES;
447 local_samples_len += sample_len_ns;
448 __this_cpu_write(running_sample_length, local_samples_len);
451 * note: this will be biased artifically low until we have
452 * seen NR_ACCUMULATED_SAMPLES. Doing it this way keeps us
453 * from having to maintain a count.
455 avg_local_sample_len = local_samples_len/NR_ACCUMULATED_SAMPLES;
457 if (avg_local_sample_len <= allowed_ns)
460 if (max_samples_per_tick <= 1)
463 max_samples_per_tick = DIV_ROUND_UP(max_samples_per_tick, 2);
464 sysctl_perf_event_sample_rate = max_samples_per_tick * HZ;
465 perf_sample_period_ns = NSEC_PER_SEC / sysctl_perf_event_sample_rate;
467 update_perf_cpu_limits();
469 if (!irq_work_queue(&perf_duration_work)) {
470 early_printk("perf interrupt took too long (%lld > %lld), lowering "
471 "kernel.perf_event_max_sample_rate to %d\n",
472 avg_local_sample_len, allowed_ns >> 1,
473 sysctl_perf_event_sample_rate);
477 static atomic64_t perf_event_id;
479 static void cpu_ctx_sched_out(struct perf_cpu_context *cpuctx,
480 enum event_type_t event_type);
482 static void cpu_ctx_sched_in(struct perf_cpu_context *cpuctx,
483 enum event_type_t event_type,
484 struct task_struct *task);
486 static void update_context_time(struct perf_event_context *ctx);
487 static u64 perf_event_time(struct perf_event *event);
489 void __weak perf_event_print_debug(void) { }
491 extern __weak const char *perf_pmu_name(void)
496 static inline u64 perf_clock(void)
498 return local_clock();
501 static inline u64 perf_event_clock(struct perf_event *event)
503 return event->clock();
506 #ifdef CONFIG_CGROUP_PERF
509 perf_cgroup_match(struct perf_event *event)
511 struct perf_event_context *ctx = event->ctx;
512 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
514 /* @event doesn't care about cgroup */
518 /* wants specific cgroup scope but @cpuctx isn't associated with any */
523 * Cgroup scoping is recursive. An event enabled for a cgroup is
524 * also enabled for all its descendant cgroups. If @cpuctx's
525 * cgroup is a descendant of @event's (the test covers identity
526 * case), it's a match.
528 return cgroup_is_descendant(cpuctx->cgrp->css.cgroup,
529 event->cgrp->css.cgroup);
532 static inline void perf_detach_cgroup(struct perf_event *event)
534 css_put(&event->cgrp->css);
538 static inline int is_cgroup_event(struct perf_event *event)
540 return event->cgrp != NULL;
543 static inline u64 perf_cgroup_event_time(struct perf_event *event)
545 struct perf_cgroup_info *t;
547 t = per_cpu_ptr(event->cgrp->info, event->cpu);
551 static inline void __update_cgrp_time(struct perf_cgroup *cgrp)
553 struct perf_cgroup_info *info;
558 info = this_cpu_ptr(cgrp->info);
560 info->time += now - info->timestamp;
561 info->timestamp = now;
564 static inline void update_cgrp_time_from_cpuctx(struct perf_cpu_context *cpuctx)
566 struct perf_cgroup *cgrp_out = cpuctx->cgrp;
568 __update_cgrp_time(cgrp_out);
571 static inline void update_cgrp_time_from_event(struct perf_event *event)
573 struct perf_cgroup *cgrp;
576 * ensure we access cgroup data only when needed and
577 * when we know the cgroup is pinned (css_get)
579 if (!is_cgroup_event(event))
582 cgrp = perf_cgroup_from_task(current, event->ctx);
584 * Do not update time when cgroup is not active
586 if (cgrp == event->cgrp)
587 __update_cgrp_time(event->cgrp);
591 perf_cgroup_set_timestamp(struct task_struct *task,
592 struct perf_event_context *ctx)
594 struct perf_cgroup *cgrp;
595 struct perf_cgroup_info *info;
598 * ctx->lock held by caller
599 * ensure we do not access cgroup data
600 * unless we have the cgroup pinned (css_get)
602 if (!task || !ctx->nr_cgroups)
605 cgrp = perf_cgroup_from_task(task, ctx);
606 info = this_cpu_ptr(cgrp->info);
607 info->timestamp = ctx->timestamp;
610 #define PERF_CGROUP_SWOUT 0x1 /* cgroup switch out every event */
611 #define PERF_CGROUP_SWIN 0x2 /* cgroup switch in events based on task */
614 * reschedule events based on the cgroup constraint of task.
616 * mode SWOUT : schedule out everything
617 * mode SWIN : schedule in based on cgroup for next
619 static void perf_cgroup_switch(struct task_struct *task, int mode)
621 struct perf_cpu_context *cpuctx;
626 * disable interrupts to avoid geting nr_cgroup
627 * changes via __perf_event_disable(). Also
630 local_irq_save(flags);
633 * we reschedule only in the presence of cgroup
634 * constrained events.
637 list_for_each_entry_rcu(pmu, &pmus, entry) {
638 cpuctx = this_cpu_ptr(pmu->pmu_cpu_context);
639 if (cpuctx->unique_pmu != pmu)
640 continue; /* ensure we process each cpuctx once */
643 * perf_cgroup_events says at least one
644 * context on this CPU has cgroup events.
646 * ctx->nr_cgroups reports the number of cgroup
647 * events for a context.
649 if (cpuctx->ctx.nr_cgroups > 0) {
650 perf_ctx_lock(cpuctx, cpuctx->task_ctx);
651 perf_pmu_disable(cpuctx->ctx.pmu);
653 if (mode & PERF_CGROUP_SWOUT) {
654 cpu_ctx_sched_out(cpuctx, EVENT_ALL);
656 * must not be done before ctxswout due
657 * to event_filter_match() in event_sched_out()
662 if (mode & PERF_CGROUP_SWIN) {
663 WARN_ON_ONCE(cpuctx->cgrp);
665 * set cgrp before ctxsw in to allow
666 * event_filter_match() to not have to pass
668 * we pass the cpuctx->ctx to perf_cgroup_from_task()
669 * because cgorup events are only per-cpu
671 cpuctx->cgrp = perf_cgroup_from_task(task, &cpuctx->ctx);
672 cpu_ctx_sched_in(cpuctx, EVENT_ALL, task);
674 perf_pmu_enable(cpuctx->ctx.pmu);
675 perf_ctx_unlock(cpuctx, cpuctx->task_ctx);
679 local_irq_restore(flags);
682 static inline void perf_cgroup_sched_out(struct task_struct *task,
683 struct task_struct *next)
685 struct perf_cgroup *cgrp1;
686 struct perf_cgroup *cgrp2 = NULL;
690 * we come here when we know perf_cgroup_events > 0
691 * we do not need to pass the ctx here because we know
692 * we are holding the rcu lock
694 cgrp1 = perf_cgroup_from_task(task, NULL);
695 cgrp2 = perf_cgroup_from_task(next, NULL);
698 * only schedule out current cgroup events if we know
699 * that we are switching to a different cgroup. Otherwise,
700 * do no touch the cgroup events.
703 perf_cgroup_switch(task, PERF_CGROUP_SWOUT);
708 static inline void perf_cgroup_sched_in(struct task_struct *prev,
709 struct task_struct *task)
711 struct perf_cgroup *cgrp1;
712 struct perf_cgroup *cgrp2 = NULL;
716 * we come here when we know perf_cgroup_events > 0
717 * we do not need to pass the ctx here because we know
718 * we are holding the rcu lock
720 cgrp1 = perf_cgroup_from_task(task, NULL);
721 cgrp2 = perf_cgroup_from_task(prev, NULL);
724 * only need to schedule in cgroup events if we are changing
725 * cgroup during ctxsw. Cgroup events were not scheduled
726 * out of ctxsw out if that was not the case.
729 perf_cgroup_switch(task, PERF_CGROUP_SWIN);
734 static inline int perf_cgroup_connect(int fd, struct perf_event *event,
735 struct perf_event_attr *attr,
736 struct perf_event *group_leader)
738 struct perf_cgroup *cgrp;
739 struct cgroup_subsys_state *css;
740 struct fd f = fdget(fd);
746 css = css_tryget_online_from_dir(f.file->f_path.dentry,
747 &perf_event_cgrp_subsys);
753 cgrp = container_of(css, struct perf_cgroup, css);
757 * all events in a group must monitor
758 * the same cgroup because a task belongs
759 * to only one perf cgroup at a time
761 if (group_leader && group_leader->cgrp != cgrp) {
762 perf_detach_cgroup(event);
771 perf_cgroup_set_shadow_time(struct perf_event *event, u64 now)
773 struct perf_cgroup_info *t;
774 t = per_cpu_ptr(event->cgrp->info, event->cpu);
775 event->shadow_ctx_time = now - t->timestamp;
779 perf_cgroup_defer_enabled(struct perf_event *event)
782 * when the current task's perf cgroup does not match
783 * the event's, we need to remember to call the
784 * perf_mark_enable() function the first time a task with
785 * a matching perf cgroup is scheduled in.
787 if (is_cgroup_event(event) && !perf_cgroup_match(event))
788 event->cgrp_defer_enabled = 1;
792 perf_cgroup_mark_enabled(struct perf_event *event,
793 struct perf_event_context *ctx)
795 struct perf_event *sub;
796 u64 tstamp = perf_event_time(event);
798 if (!event->cgrp_defer_enabled)
801 event->cgrp_defer_enabled = 0;
803 event->tstamp_enabled = tstamp - event->total_time_enabled;
804 list_for_each_entry(sub, &event->sibling_list, group_entry) {
805 if (sub->state >= PERF_EVENT_STATE_INACTIVE) {
806 sub->tstamp_enabled = tstamp - sub->total_time_enabled;
807 sub->cgrp_defer_enabled = 0;
811 #else /* !CONFIG_CGROUP_PERF */
814 perf_cgroup_match(struct perf_event *event)
819 static inline void perf_detach_cgroup(struct perf_event *event)
822 static inline int is_cgroup_event(struct perf_event *event)
827 static inline u64 perf_cgroup_event_cgrp_time(struct perf_event *event)
832 static inline void update_cgrp_time_from_event(struct perf_event *event)
836 static inline void update_cgrp_time_from_cpuctx(struct perf_cpu_context *cpuctx)
840 static inline void perf_cgroup_sched_out(struct task_struct *task,
841 struct task_struct *next)
845 static inline void perf_cgroup_sched_in(struct task_struct *prev,
846 struct task_struct *task)
850 static inline int perf_cgroup_connect(pid_t pid, struct perf_event *event,
851 struct perf_event_attr *attr,
852 struct perf_event *group_leader)
858 perf_cgroup_set_timestamp(struct task_struct *task,
859 struct perf_event_context *ctx)
864 perf_cgroup_switch(struct task_struct *task, struct task_struct *next)
869 perf_cgroup_set_shadow_time(struct perf_event *event, u64 now)
873 static inline u64 perf_cgroup_event_time(struct perf_event *event)
879 perf_cgroup_defer_enabled(struct perf_event *event)
884 perf_cgroup_mark_enabled(struct perf_event *event,
885 struct perf_event_context *ctx)
891 * set default to be dependent on timer tick just
894 #define PERF_CPU_HRTIMER (1000 / HZ)
896 * function must be called with interrupts disbled
898 static enum hrtimer_restart perf_mux_hrtimer_handler(struct hrtimer *hr)
900 struct perf_cpu_context *cpuctx;
903 WARN_ON(!irqs_disabled());
905 cpuctx = container_of(hr, struct perf_cpu_context, hrtimer);
906 rotations = perf_rotate_context(cpuctx);
908 raw_spin_lock(&cpuctx->hrtimer_lock);
910 hrtimer_forward_now(hr, cpuctx->hrtimer_interval);
912 cpuctx->hrtimer_active = 0;
913 raw_spin_unlock(&cpuctx->hrtimer_lock);
915 return rotations ? HRTIMER_RESTART : HRTIMER_NORESTART;
918 static void __perf_mux_hrtimer_init(struct perf_cpu_context *cpuctx, int cpu)
920 struct hrtimer *timer = &cpuctx->hrtimer;
921 struct pmu *pmu = cpuctx->ctx.pmu;
924 /* no multiplexing needed for SW PMU */
925 if (pmu->task_ctx_nr == perf_sw_context)
929 * check default is sane, if not set then force to
930 * default interval (1/tick)
932 interval = pmu->hrtimer_interval_ms;
934 interval = pmu->hrtimer_interval_ms = PERF_CPU_HRTIMER;
936 cpuctx->hrtimer_interval = ns_to_ktime(NSEC_PER_MSEC * interval);
938 raw_spin_lock_init(&cpuctx->hrtimer_lock);
939 hrtimer_init(timer, CLOCK_MONOTONIC, HRTIMER_MODE_ABS_PINNED);
940 timer->function = perf_mux_hrtimer_handler;
943 static int perf_mux_hrtimer_restart(struct perf_cpu_context *cpuctx)
945 struct hrtimer *timer = &cpuctx->hrtimer;
946 struct pmu *pmu = cpuctx->ctx.pmu;
950 if (pmu->task_ctx_nr == perf_sw_context)
953 raw_spin_lock_irqsave(&cpuctx->hrtimer_lock, flags);
954 if (!cpuctx->hrtimer_active) {
955 cpuctx->hrtimer_active = 1;
956 hrtimer_forward_now(timer, cpuctx->hrtimer_interval);
957 hrtimer_start_expires(timer, HRTIMER_MODE_ABS_PINNED);
959 raw_spin_unlock_irqrestore(&cpuctx->hrtimer_lock, flags);
964 void perf_pmu_disable(struct pmu *pmu)
966 int *count = this_cpu_ptr(pmu->pmu_disable_count);
968 pmu->pmu_disable(pmu);
971 void perf_pmu_enable(struct pmu *pmu)
973 int *count = this_cpu_ptr(pmu->pmu_disable_count);
975 pmu->pmu_enable(pmu);
978 static DEFINE_PER_CPU(struct list_head, active_ctx_list);
981 * perf_event_ctx_activate(), perf_event_ctx_deactivate(), and
982 * perf_event_task_tick() are fully serialized because they're strictly cpu
983 * affine and perf_event_ctx{activate,deactivate} are called with IRQs
984 * disabled, while perf_event_task_tick is called from IRQ context.
986 static void perf_event_ctx_activate(struct perf_event_context *ctx)
988 struct list_head *head = this_cpu_ptr(&active_ctx_list);
990 WARN_ON(!irqs_disabled());
992 WARN_ON(!list_empty(&ctx->active_ctx_list));
994 list_add(&ctx->active_ctx_list, head);
997 static void perf_event_ctx_deactivate(struct perf_event_context *ctx)
999 WARN_ON(!irqs_disabled());
1001 WARN_ON(list_empty(&ctx->active_ctx_list));
1003 list_del_init(&ctx->active_ctx_list);
1006 static void get_ctx(struct perf_event_context *ctx)
1008 WARN_ON(!atomic_inc_not_zero(&ctx->refcount));
1011 static void free_ctx(struct rcu_head *head)
1013 struct perf_event_context *ctx;
1015 ctx = container_of(head, struct perf_event_context, rcu_head);
1016 kfree(ctx->task_ctx_data);
1020 static void put_ctx(struct perf_event_context *ctx)
1022 if (atomic_dec_and_test(&ctx->refcount)) {
1023 if (ctx->parent_ctx)
1024 put_ctx(ctx->parent_ctx);
1025 if (ctx->task && ctx->task != TASK_TOMBSTONE)
1026 put_task_struct(ctx->task);
1027 call_rcu(&ctx->rcu_head, free_ctx);
1032 * Because of perf_event::ctx migration in sys_perf_event_open::move_group and
1033 * perf_pmu_migrate_context() we need some magic.
1035 * Those places that change perf_event::ctx will hold both
1036 * perf_event_ctx::mutex of the 'old' and 'new' ctx value.
1038 * Lock ordering is by mutex address. There are two other sites where
1039 * perf_event_context::mutex nests and those are:
1041 * - perf_event_exit_task_context() [ child , 0 ]
1042 * perf_event_exit_event()
1043 * put_event() [ parent, 1 ]
1045 * - perf_event_init_context() [ parent, 0 ]
1046 * inherit_task_group()
1049 * perf_event_alloc()
1051 * perf_try_init_event() [ child , 1 ]
1053 * While it appears there is an obvious deadlock here -- the parent and child
1054 * nesting levels are inverted between the two. This is in fact safe because
1055 * life-time rules separate them. That is an exiting task cannot fork, and a
1056 * spawning task cannot (yet) exit.
1058 * But remember that that these are parent<->child context relations, and
1059 * migration does not affect children, therefore these two orderings should not
1062 * The change in perf_event::ctx does not affect children (as claimed above)
1063 * because the sys_perf_event_open() case will install a new event and break
1064 * the ctx parent<->child relation, and perf_pmu_migrate_context() is only
1065 * concerned with cpuctx and that doesn't have children.
1067 * The places that change perf_event::ctx will issue:
1069 * perf_remove_from_context();
1070 * synchronize_rcu();
1071 * perf_install_in_context();
1073 * to affect the change. The remove_from_context() + synchronize_rcu() should
1074 * quiesce the event, after which we can install it in the new location. This
1075 * means that only external vectors (perf_fops, prctl) can perturb the event
1076 * while in transit. Therefore all such accessors should also acquire
1077 * perf_event_context::mutex to serialize against this.
1079 * However; because event->ctx can change while we're waiting to acquire
1080 * ctx->mutex we must be careful and use the below perf_event_ctx_lock()
1084 * task_struct::perf_event_mutex
1085 * perf_event_context::mutex
1086 * perf_event::child_mutex;
1087 * perf_event_context::lock
1088 * perf_event::mmap_mutex
1091 static struct perf_event_context *
1092 perf_event_ctx_lock_nested(struct perf_event *event, int nesting)
1094 struct perf_event_context *ctx;
1098 ctx = ACCESS_ONCE(event->ctx);
1099 if (!atomic_inc_not_zero(&ctx->refcount)) {
1105 mutex_lock_nested(&ctx->mutex, nesting);
1106 if (event->ctx != ctx) {
1107 mutex_unlock(&ctx->mutex);
1115 static inline struct perf_event_context *
1116 perf_event_ctx_lock(struct perf_event *event)
1118 return perf_event_ctx_lock_nested(event, 0);
1121 static void perf_event_ctx_unlock(struct perf_event *event,
1122 struct perf_event_context *ctx)
1124 mutex_unlock(&ctx->mutex);
1129 * This must be done under the ctx->lock, such as to serialize against
1130 * context_equiv(), therefore we cannot call put_ctx() since that might end up
1131 * calling scheduler related locks and ctx->lock nests inside those.
1133 static __must_check struct perf_event_context *
1134 unclone_ctx(struct perf_event_context *ctx)
1136 struct perf_event_context *parent_ctx = ctx->parent_ctx;
1138 lockdep_assert_held(&ctx->lock);
1141 ctx->parent_ctx = NULL;
1147 static u32 perf_event_pid(struct perf_event *event, struct task_struct *p)
1150 * only top level events have the pid namespace they were created in
1153 event = event->parent;
1155 return task_tgid_nr_ns(p, event->ns);
1158 static u32 perf_event_tid(struct perf_event *event, struct task_struct *p)
1161 * only top level events have the pid namespace they were created in
1164 event = event->parent;
1166 return task_pid_nr_ns(p, event->ns);
1170 * If we inherit events we want to return the parent event id
1173 static u64 primary_event_id(struct perf_event *event)
1178 id = event->parent->id;
1184 * Get the perf_event_context for a task and lock it.
1186 * This has to cope with with the fact that until it is locked,
1187 * the context could get moved to another task.
1189 static struct perf_event_context *
1190 perf_lock_task_context(struct task_struct *task, int ctxn, unsigned long *flags)
1192 struct perf_event_context *ctx;
1196 * One of the few rules of preemptible RCU is that one cannot do
1197 * rcu_read_unlock() while holding a scheduler (or nested) lock when
1198 * part of the read side critical section was irqs-enabled -- see
1199 * rcu_read_unlock_special().
1201 * Since ctx->lock nests under rq->lock we must ensure the entire read
1202 * side critical section has interrupts disabled.
1204 local_irq_save(*flags);
1206 ctx = rcu_dereference(task->perf_event_ctxp[ctxn]);
1209 * If this context is a clone of another, it might
1210 * get swapped for another underneath us by
1211 * perf_event_task_sched_out, though the
1212 * rcu_read_lock() protects us from any context
1213 * getting freed. Lock the context and check if it
1214 * got swapped before we could get the lock, and retry
1215 * if so. If we locked the right context, then it
1216 * can't get swapped on us any more.
1218 raw_spin_lock(&ctx->lock);
1219 if (ctx != rcu_dereference(task->perf_event_ctxp[ctxn])) {
1220 raw_spin_unlock(&ctx->lock);
1222 local_irq_restore(*flags);
1226 if (ctx->task == TASK_TOMBSTONE ||
1227 !atomic_inc_not_zero(&ctx->refcount)) {
1228 raw_spin_unlock(&ctx->lock);
1231 WARN_ON_ONCE(ctx->task != task);
1236 local_irq_restore(*flags);
1241 * Get the context for a task and increment its pin_count so it
1242 * can't get swapped to another task. This also increments its
1243 * reference count so that the context can't get freed.
1245 static struct perf_event_context *
1246 perf_pin_task_context(struct task_struct *task, int ctxn)
1248 struct perf_event_context *ctx;
1249 unsigned long flags;
1251 ctx = perf_lock_task_context(task, ctxn, &flags);
1254 raw_spin_unlock_irqrestore(&ctx->lock, flags);
1259 static void perf_unpin_context(struct perf_event_context *ctx)
1261 unsigned long flags;
1263 raw_spin_lock_irqsave(&ctx->lock, flags);
1265 raw_spin_unlock_irqrestore(&ctx->lock, flags);
1269 * Update the record of the current time in a context.
1271 static void update_context_time(struct perf_event_context *ctx)
1273 u64 now = perf_clock();
1275 ctx->time += now - ctx->timestamp;
1276 ctx->timestamp = now;
1279 static u64 perf_event_time(struct perf_event *event)
1281 struct perf_event_context *ctx = event->ctx;
1283 if (is_cgroup_event(event))
1284 return perf_cgroup_event_time(event);
1286 return ctx ? ctx->time : 0;
1290 * Update the total_time_enabled and total_time_running fields for a event.
1291 * The caller of this function needs to hold the ctx->lock.
1293 static void update_event_times(struct perf_event *event)
1295 struct perf_event_context *ctx = event->ctx;
1298 if (event->state < PERF_EVENT_STATE_INACTIVE ||
1299 event->group_leader->state < PERF_EVENT_STATE_INACTIVE)
1302 * in cgroup mode, time_enabled represents
1303 * the time the event was enabled AND active
1304 * tasks were in the monitored cgroup. This is
1305 * independent of the activity of the context as
1306 * there may be a mix of cgroup and non-cgroup events.
1308 * That is why we treat cgroup events differently
1311 if (is_cgroup_event(event))
1312 run_end = perf_cgroup_event_time(event);
1313 else if (ctx->is_active)
1314 run_end = ctx->time;
1316 run_end = event->tstamp_stopped;
1318 event->total_time_enabled = run_end - event->tstamp_enabled;
1320 if (event->state == PERF_EVENT_STATE_INACTIVE)
1321 run_end = event->tstamp_stopped;
1323 run_end = perf_event_time(event);
1325 event->total_time_running = run_end - event->tstamp_running;
1330 * Update total_time_enabled and total_time_running for all events in a group.
1332 static void update_group_times(struct perf_event *leader)
1334 struct perf_event *event;
1336 update_event_times(leader);
1337 list_for_each_entry(event, &leader->sibling_list, group_entry)
1338 update_event_times(event);
1341 static struct list_head *
1342 ctx_group_list(struct perf_event *event, struct perf_event_context *ctx)
1344 if (event->attr.pinned)
1345 return &ctx->pinned_groups;
1347 return &ctx->flexible_groups;
1351 * Add a event from the lists for its context.
1352 * Must be called with ctx->mutex and ctx->lock held.
1355 list_add_event(struct perf_event *event, struct perf_event_context *ctx)
1357 lockdep_assert_held(&ctx->lock);
1359 WARN_ON_ONCE(event->attach_state & PERF_ATTACH_CONTEXT);
1360 event->attach_state |= PERF_ATTACH_CONTEXT;
1363 * If we're a stand alone event or group leader, we go to the context
1364 * list, group events are kept attached to the group so that
1365 * perf_group_detach can, at all times, locate all siblings.
1367 if (event->group_leader == event) {
1368 struct list_head *list;
1370 if (is_software_event(event))
1371 event->group_flags |= PERF_GROUP_SOFTWARE;
1373 list = ctx_group_list(event, ctx);
1374 list_add_tail(&event->group_entry, list);
1377 if (is_cgroup_event(event))
1380 list_add_rcu(&event->event_entry, &ctx->event_list);
1382 if (event->attr.inherit_stat)
1389 * Initialize event state based on the perf_event_attr::disabled.
1391 static inline void perf_event__state_init(struct perf_event *event)
1393 event->state = event->attr.disabled ? PERF_EVENT_STATE_OFF :
1394 PERF_EVENT_STATE_INACTIVE;
1397 static void __perf_event_read_size(struct perf_event *event, int nr_siblings)
1399 int entry = sizeof(u64); /* value */
1403 if (event->attr.read_format & PERF_FORMAT_TOTAL_TIME_ENABLED)
1404 size += sizeof(u64);
1406 if (event->attr.read_format & PERF_FORMAT_TOTAL_TIME_RUNNING)
1407 size += sizeof(u64);
1409 if (event->attr.read_format & PERF_FORMAT_ID)
1410 entry += sizeof(u64);
1412 if (event->attr.read_format & PERF_FORMAT_GROUP) {
1414 size += sizeof(u64);
1418 event->read_size = size;
1421 static void __perf_event_header_size(struct perf_event *event, u64 sample_type)
1423 struct perf_sample_data *data;
1426 if (sample_type & PERF_SAMPLE_IP)
1427 size += sizeof(data->ip);
1429 if (sample_type & PERF_SAMPLE_ADDR)
1430 size += sizeof(data->addr);
1432 if (sample_type & PERF_SAMPLE_PERIOD)
1433 size += sizeof(data->period);
1435 if (sample_type & PERF_SAMPLE_WEIGHT)
1436 size += sizeof(data->weight);
1438 if (sample_type & PERF_SAMPLE_READ)
1439 size += event->read_size;
1441 if (sample_type & PERF_SAMPLE_DATA_SRC)
1442 size += sizeof(data->data_src.val);
1444 if (sample_type & PERF_SAMPLE_TRANSACTION)
1445 size += sizeof(data->txn);
1447 event->header_size = size;
1451 * Called at perf_event creation and when events are attached/detached from a
1454 static void perf_event__header_size(struct perf_event *event)
1456 __perf_event_read_size(event,
1457 event->group_leader->nr_siblings);
1458 __perf_event_header_size(event, event->attr.sample_type);
1461 static void perf_event__id_header_size(struct perf_event *event)
1463 struct perf_sample_data *data;
1464 u64 sample_type = event->attr.sample_type;
1467 if (sample_type & PERF_SAMPLE_TID)
1468 size += sizeof(data->tid_entry);
1470 if (sample_type & PERF_SAMPLE_TIME)
1471 size += sizeof(data->time);
1473 if (sample_type & PERF_SAMPLE_IDENTIFIER)
1474 size += sizeof(data->id);
1476 if (sample_type & PERF_SAMPLE_ID)
1477 size += sizeof(data->id);
1479 if (sample_type & PERF_SAMPLE_STREAM_ID)
1480 size += sizeof(data->stream_id);
1482 if (sample_type & PERF_SAMPLE_CPU)
1483 size += sizeof(data->cpu_entry);
1485 event->id_header_size = size;
1488 static bool perf_event_validate_size(struct perf_event *event)
1491 * The values computed here will be over-written when we actually
1494 __perf_event_read_size(event, event->group_leader->nr_siblings + 1);
1495 __perf_event_header_size(event, event->attr.sample_type & ~PERF_SAMPLE_READ);
1496 perf_event__id_header_size(event);
1499 * Sum the lot; should not exceed the 64k limit we have on records.
1500 * Conservative limit to allow for callchains and other variable fields.
1502 if (event->read_size + event->header_size +
1503 event->id_header_size + sizeof(struct perf_event_header) >= 16*1024)
1509 static void perf_group_attach(struct perf_event *event)
1511 struct perf_event *group_leader = event->group_leader, *pos;
1514 * We can have double attach due to group movement in perf_event_open.
1516 if (event->attach_state & PERF_ATTACH_GROUP)
1519 event->attach_state |= PERF_ATTACH_GROUP;
1521 if (group_leader == event)
1524 WARN_ON_ONCE(group_leader->ctx != event->ctx);
1526 if (group_leader->group_flags & PERF_GROUP_SOFTWARE &&
1527 !is_software_event(event))
1528 group_leader->group_flags &= ~PERF_GROUP_SOFTWARE;
1530 list_add_tail(&event->group_entry, &group_leader->sibling_list);
1531 group_leader->nr_siblings++;
1533 perf_event__header_size(group_leader);
1535 list_for_each_entry(pos, &group_leader->sibling_list, group_entry)
1536 perf_event__header_size(pos);
1540 * Remove a event from the lists for its context.
1541 * Must be called with ctx->mutex and ctx->lock held.
1544 list_del_event(struct perf_event *event, struct perf_event_context *ctx)
1546 struct perf_cpu_context *cpuctx;
1548 WARN_ON_ONCE(event->ctx != ctx);
1549 lockdep_assert_held(&ctx->lock);
1552 * We can have double detach due to exit/hot-unplug + close.
1554 if (!(event->attach_state & PERF_ATTACH_CONTEXT))
1557 event->attach_state &= ~PERF_ATTACH_CONTEXT;
1559 if (is_cgroup_event(event)) {
1562 * Because cgroup events are always per-cpu events, this will
1563 * always be called from the right CPU.
1565 cpuctx = __get_cpu_context(ctx);
1567 * If there are no more cgroup events then clear cgrp to avoid
1568 * stale pointer in update_cgrp_time_from_cpuctx().
1570 if (!ctx->nr_cgroups)
1571 cpuctx->cgrp = NULL;
1575 if (event->attr.inherit_stat)
1578 list_del_rcu(&event->event_entry);
1580 if (event->group_leader == event)
1581 list_del_init(&event->group_entry);
1583 update_group_times(event);
1586 * If event was in error state, then keep it
1587 * that way, otherwise bogus counts will be
1588 * returned on read(). The only way to get out
1589 * of error state is by explicit re-enabling
1592 if (event->state > PERF_EVENT_STATE_OFF)
1593 event->state = PERF_EVENT_STATE_OFF;
1598 static void perf_group_detach(struct perf_event *event)
1600 struct perf_event *sibling, *tmp;
1601 struct list_head *list = NULL;
1604 * We can have double detach due to exit/hot-unplug + close.
1606 if (!(event->attach_state & PERF_ATTACH_GROUP))
1609 event->attach_state &= ~PERF_ATTACH_GROUP;
1612 * If this is a sibling, remove it from its group.
1614 if (event->group_leader != event) {
1615 list_del_init(&event->group_entry);
1616 event->group_leader->nr_siblings--;
1620 if (!list_empty(&event->group_entry))
1621 list = &event->group_entry;
1624 * If this was a group event with sibling events then
1625 * upgrade the siblings to singleton events by adding them
1626 * to whatever list we are on.
1628 list_for_each_entry_safe(sibling, tmp, &event->sibling_list, group_entry) {
1630 list_move_tail(&sibling->group_entry, list);
1631 sibling->group_leader = sibling;
1633 /* Inherit group flags from the previous leader */
1634 sibling->group_flags = event->group_flags;
1636 WARN_ON_ONCE(sibling->ctx != event->ctx);
1640 perf_event__header_size(event->group_leader);
1642 list_for_each_entry(tmp, &event->group_leader->sibling_list, group_entry)
1643 perf_event__header_size(tmp);
1646 static bool is_orphaned_event(struct perf_event *event)
1648 return event->state == PERF_EVENT_STATE_EXIT;
1651 static inline int pmu_filter_match(struct perf_event *event)
1653 struct pmu *pmu = event->pmu;
1654 return pmu->filter_match ? pmu->filter_match(event) : 1;
1658 event_filter_match(struct perf_event *event)
1660 return (event->cpu == -1 || event->cpu == smp_processor_id())
1661 && perf_cgroup_match(event) && pmu_filter_match(event);
1665 event_sched_out(struct perf_event *event,
1666 struct perf_cpu_context *cpuctx,
1667 struct perf_event_context *ctx)
1669 u64 tstamp = perf_event_time(event);
1672 WARN_ON_ONCE(event->ctx != ctx);
1673 lockdep_assert_held(&ctx->lock);
1676 * An event which could not be activated because of
1677 * filter mismatch still needs to have its timings
1678 * maintained, otherwise bogus information is return
1679 * via read() for time_enabled, time_running:
1681 if (event->state == PERF_EVENT_STATE_INACTIVE
1682 && !event_filter_match(event)) {
1683 delta = tstamp - event->tstamp_stopped;
1684 event->tstamp_running += delta;
1685 event->tstamp_stopped = tstamp;
1688 if (event->state != PERF_EVENT_STATE_ACTIVE)
1691 perf_pmu_disable(event->pmu);
1693 event->state = PERF_EVENT_STATE_INACTIVE;
1694 if (event->pending_disable) {
1695 event->pending_disable = 0;
1696 event->state = PERF_EVENT_STATE_OFF;
1698 event->tstamp_stopped = tstamp;
1699 event->pmu->del(event, 0);
1702 if (!is_software_event(event))
1703 cpuctx->active_oncpu--;
1704 if (!--ctx->nr_active)
1705 perf_event_ctx_deactivate(ctx);
1706 if (event->attr.freq && event->attr.sample_freq)
1708 if (event->attr.exclusive || !cpuctx->active_oncpu)
1709 cpuctx->exclusive = 0;
1711 perf_pmu_enable(event->pmu);
1715 group_sched_out(struct perf_event *group_event,
1716 struct perf_cpu_context *cpuctx,
1717 struct perf_event_context *ctx)
1719 struct perf_event *event;
1720 int state = group_event->state;
1722 event_sched_out(group_event, cpuctx, ctx);
1725 * Schedule out siblings (if any):
1727 list_for_each_entry(event, &group_event->sibling_list, group_entry)
1728 event_sched_out(event, cpuctx, ctx);
1730 if (state == PERF_EVENT_STATE_ACTIVE && group_event->attr.exclusive)
1731 cpuctx->exclusive = 0;
1734 #define DETACH_GROUP 0x01UL
1735 #define DETACH_STATE 0x02UL
1738 * Cross CPU call to remove a performance event
1740 * We disable the event on the hardware level first. After that we
1741 * remove it from the context list.
1744 __perf_remove_from_context(struct perf_event *event,
1745 struct perf_cpu_context *cpuctx,
1746 struct perf_event_context *ctx,
1749 unsigned long flags = (unsigned long)info;
1751 event_sched_out(event, cpuctx, ctx);
1752 if (flags & DETACH_GROUP)
1753 perf_group_detach(event);
1754 list_del_event(event, ctx);
1755 if (flags & DETACH_STATE)
1756 event->state = PERF_EVENT_STATE_EXIT;
1758 if (!ctx->nr_events && ctx->is_active) {
1761 WARN_ON_ONCE(cpuctx->task_ctx != ctx);
1762 cpuctx->task_ctx = NULL;
1768 * Remove the event from a task's (or a CPU's) list of events.
1770 * If event->ctx is a cloned context, callers must make sure that
1771 * every task struct that event->ctx->task could possibly point to
1772 * remains valid. This is OK when called from perf_release since
1773 * that only calls us on the top-level context, which can't be a clone.
1774 * When called from perf_event_exit_task, it's OK because the
1775 * context has been detached from its task.
1777 static void perf_remove_from_context(struct perf_event *event, unsigned long flags)
1779 lockdep_assert_held(&event->ctx->mutex);
1781 event_function_call(event, __perf_remove_from_context, (void *)flags);
1785 * Cross CPU call to disable a performance event
1787 static void __perf_event_disable(struct perf_event *event,
1788 struct perf_cpu_context *cpuctx,
1789 struct perf_event_context *ctx,
1792 if (event->state < PERF_EVENT_STATE_INACTIVE)
1795 update_context_time(ctx);
1796 update_cgrp_time_from_event(event);
1797 update_group_times(event);
1798 if (event == event->group_leader)
1799 group_sched_out(event, cpuctx, ctx);
1801 event_sched_out(event, cpuctx, ctx);
1802 event->state = PERF_EVENT_STATE_OFF;
1808 * If event->ctx is a cloned context, callers must make sure that
1809 * every task struct that event->ctx->task could possibly point to
1810 * remains valid. This condition is satisifed when called through
1811 * perf_event_for_each_child or perf_event_for_each because they
1812 * hold the top-level event's child_mutex, so any descendant that
1813 * goes to exit will block in perf_event_exit_event().
1815 * When called from perf_pending_event it's OK because event->ctx
1816 * is the current context on this CPU and preemption is disabled,
1817 * hence we can't get into perf_event_task_sched_out for this context.
1819 static void _perf_event_disable(struct perf_event *event)
1821 struct perf_event_context *ctx = event->ctx;
1823 raw_spin_lock_irq(&ctx->lock);
1824 if (event->state <= PERF_EVENT_STATE_OFF) {
1825 raw_spin_unlock_irq(&ctx->lock);
1828 raw_spin_unlock_irq(&ctx->lock);
1830 event_function_call(event, __perf_event_disable, NULL);
1833 void perf_event_disable_local(struct perf_event *event)
1835 event_function_local(event, __perf_event_disable, NULL);
1839 * Strictly speaking kernel users cannot create groups and therefore this
1840 * interface does not need the perf_event_ctx_lock() magic.
1842 void perf_event_disable(struct perf_event *event)
1844 struct perf_event_context *ctx;
1846 ctx = perf_event_ctx_lock(event);
1847 _perf_event_disable(event);
1848 perf_event_ctx_unlock(event, ctx);
1850 EXPORT_SYMBOL_GPL(perf_event_disable);
1852 static void perf_set_shadow_time(struct perf_event *event,
1853 struct perf_event_context *ctx,
1857 * use the correct time source for the time snapshot
1859 * We could get by without this by leveraging the
1860 * fact that to get to this function, the caller
1861 * has most likely already called update_context_time()
1862 * and update_cgrp_time_xx() and thus both timestamp
1863 * are identical (or very close). Given that tstamp is,
1864 * already adjusted for cgroup, we could say that:
1865 * tstamp - ctx->timestamp
1867 * tstamp - cgrp->timestamp.
1869 * Then, in perf_output_read(), the calculation would
1870 * work with no changes because:
1871 * - event is guaranteed scheduled in
1872 * - no scheduled out in between
1873 * - thus the timestamp would be the same
1875 * But this is a bit hairy.
1877 * So instead, we have an explicit cgroup call to remain
1878 * within the time time source all along. We believe it
1879 * is cleaner and simpler to understand.
1881 if (is_cgroup_event(event))
1882 perf_cgroup_set_shadow_time(event, tstamp);
1884 event->shadow_ctx_time = tstamp - ctx->timestamp;
1887 #define MAX_INTERRUPTS (~0ULL)
1889 static void perf_log_throttle(struct perf_event *event, int enable);
1890 static void perf_log_itrace_start(struct perf_event *event);
1893 event_sched_in(struct perf_event *event,
1894 struct perf_cpu_context *cpuctx,
1895 struct perf_event_context *ctx)
1897 u64 tstamp = perf_event_time(event);
1900 lockdep_assert_held(&ctx->lock);
1902 if (event->state <= PERF_EVENT_STATE_OFF)
1905 event->state = PERF_EVENT_STATE_ACTIVE;
1906 event->oncpu = smp_processor_id();
1909 * Unthrottle events, since we scheduled we might have missed several
1910 * ticks already, also for a heavily scheduling task there is little
1911 * guarantee it'll get a tick in a timely manner.
1913 if (unlikely(event->hw.interrupts == MAX_INTERRUPTS)) {
1914 perf_log_throttle(event, 1);
1915 event->hw.interrupts = 0;
1919 * The new state must be visible before we turn it on in the hardware:
1923 perf_pmu_disable(event->pmu);
1925 perf_set_shadow_time(event, ctx, tstamp);
1927 perf_log_itrace_start(event);
1929 if (event->pmu->add(event, PERF_EF_START)) {
1930 event->state = PERF_EVENT_STATE_INACTIVE;
1936 event->tstamp_running += tstamp - event->tstamp_stopped;
1938 if (!is_software_event(event))
1939 cpuctx->active_oncpu++;
1940 if (!ctx->nr_active++)
1941 perf_event_ctx_activate(ctx);
1942 if (event->attr.freq && event->attr.sample_freq)
1945 if (event->attr.exclusive)
1946 cpuctx->exclusive = 1;
1949 perf_pmu_enable(event->pmu);
1955 group_sched_in(struct perf_event *group_event,
1956 struct perf_cpu_context *cpuctx,
1957 struct perf_event_context *ctx)
1959 struct perf_event *event, *partial_group = NULL;
1960 struct pmu *pmu = ctx->pmu;
1961 u64 now = ctx->time;
1962 bool simulate = false;
1964 if (group_event->state == PERF_EVENT_STATE_OFF)
1967 pmu->start_txn(pmu, PERF_PMU_TXN_ADD);
1969 if (event_sched_in(group_event, cpuctx, ctx)) {
1970 pmu->cancel_txn(pmu);
1971 perf_mux_hrtimer_restart(cpuctx);
1976 * Schedule in siblings as one group (if any):
1978 list_for_each_entry(event, &group_event->sibling_list, group_entry) {
1979 if (event_sched_in(event, cpuctx, ctx)) {
1980 partial_group = event;
1985 if (!pmu->commit_txn(pmu))
1990 * Groups can be scheduled in as one unit only, so undo any
1991 * partial group before returning:
1992 * The events up to the failed event are scheduled out normally,
1993 * tstamp_stopped will be updated.
1995 * The failed events and the remaining siblings need to have
1996 * their timings updated as if they had gone thru event_sched_in()
1997 * and event_sched_out(). This is required to get consistent timings
1998 * across the group. This also takes care of the case where the group
1999 * could never be scheduled by ensuring tstamp_stopped is set to mark
2000 * the time the event was actually stopped, such that time delta
2001 * calculation in update_event_times() is correct.
2003 list_for_each_entry(event, &group_event->sibling_list, group_entry) {
2004 if (event == partial_group)
2008 event->tstamp_running += now - event->tstamp_stopped;
2009 event->tstamp_stopped = now;
2011 event_sched_out(event, cpuctx, ctx);
2014 event_sched_out(group_event, cpuctx, ctx);
2016 pmu->cancel_txn(pmu);
2018 perf_mux_hrtimer_restart(cpuctx);
2024 * Work out whether we can put this event group on the CPU now.
2026 static int group_can_go_on(struct perf_event *event,
2027 struct perf_cpu_context *cpuctx,
2031 * Groups consisting entirely of software events can always go on.
2033 if (event->group_flags & PERF_GROUP_SOFTWARE)
2036 * If an exclusive group is already on, no other hardware
2039 if (cpuctx->exclusive)
2042 * If this group is exclusive and there are already
2043 * events on the CPU, it can't go on.
2045 if (event->attr.exclusive && cpuctx->active_oncpu)
2048 * Otherwise, try to add it if all previous groups were able
2054 static void add_event_to_ctx(struct perf_event *event,
2055 struct perf_event_context *ctx)
2057 u64 tstamp = perf_event_time(event);
2059 list_add_event(event, ctx);
2060 perf_group_attach(event);
2061 event->tstamp_enabled = tstamp;
2062 event->tstamp_running = tstamp;
2063 event->tstamp_stopped = tstamp;
2066 static void task_ctx_sched_out(struct perf_cpu_context *cpuctx,
2067 struct perf_event_context *ctx);
2069 ctx_sched_in(struct perf_event_context *ctx,
2070 struct perf_cpu_context *cpuctx,
2071 enum event_type_t event_type,
2072 struct task_struct *task);
2074 static void perf_event_sched_in(struct perf_cpu_context *cpuctx,
2075 struct perf_event_context *ctx,
2076 struct task_struct *task)
2078 cpu_ctx_sched_in(cpuctx, EVENT_PINNED, task);
2080 ctx_sched_in(ctx, cpuctx, EVENT_PINNED, task);
2081 cpu_ctx_sched_in(cpuctx, EVENT_FLEXIBLE, task);
2083 ctx_sched_in(ctx, cpuctx, EVENT_FLEXIBLE, task);
2086 static void ctx_resched(struct perf_cpu_context *cpuctx,
2087 struct perf_event_context *task_ctx)
2089 perf_pmu_disable(cpuctx->ctx.pmu);
2091 task_ctx_sched_out(cpuctx, task_ctx);
2092 cpu_ctx_sched_out(cpuctx, EVENT_ALL);
2093 perf_event_sched_in(cpuctx, task_ctx, current);
2094 perf_pmu_enable(cpuctx->ctx.pmu);
2098 * Cross CPU call to install and enable a performance event
2100 * Must be called with ctx->mutex held
2102 static int __perf_install_in_context(void *info)
2104 struct perf_event_context *ctx = info;
2105 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
2106 struct perf_event_context *task_ctx = cpuctx->task_ctx;
2108 raw_spin_lock(&cpuctx->ctx.lock);
2110 raw_spin_lock(&ctx->lock);
2112 * If we hit the 'wrong' task, we've since scheduled and
2113 * everything should be sorted, nothing to do!
2116 if (ctx->task != current)
2120 * If task_ctx is set, it had better be to us.
2122 WARN_ON_ONCE(cpuctx->task_ctx != ctx && cpuctx->task_ctx);
2123 } else if (task_ctx) {
2124 raw_spin_lock(&task_ctx->lock);
2127 ctx_resched(cpuctx, task_ctx);
2129 perf_ctx_unlock(cpuctx, task_ctx);
2135 * Attach a performance event to a context
2138 perf_install_in_context(struct perf_event_context *ctx,
2139 struct perf_event *event,
2142 struct task_struct *task = NULL;
2144 lockdep_assert_held(&ctx->mutex);
2147 if (event->cpu != -1)
2151 * Installing events is tricky because we cannot rely on ctx->is_active
2152 * to be set in case this is the nr_events 0 -> 1 transition.
2154 * So what we do is we add the event to the list here, which will allow
2155 * a future context switch to DTRT and then send a racy IPI. If the IPI
2156 * fails to hit the right task, this means a context switch must have
2157 * happened and that will have taken care of business.
2159 raw_spin_lock_irq(&ctx->lock);
2163 * If between ctx = find_get_context() and mutex_lock(&ctx->mutex) the
2164 * ctx gets destroyed, we must not install an event into it.
2166 * This is normally tested for after we acquire the mutex, so this is
2169 if (WARN_ON_ONCE(task == TASK_TOMBSTONE)) {
2170 raw_spin_unlock_irq(&ctx->lock);
2174 if (ctx->is_active) {
2175 update_context_time(ctx);
2176 update_cgrp_time_from_event(event);
2179 add_event_to_ctx(event, ctx);
2180 raw_spin_unlock_irq(&ctx->lock);
2183 task_function_call(task, __perf_install_in_context, ctx);
2185 cpu_function_call(cpu, __perf_install_in_context, ctx);
2189 * Put a event into inactive state and update time fields.
2190 * Enabling the leader of a group effectively enables all
2191 * the group members that aren't explicitly disabled, so we
2192 * have to update their ->tstamp_enabled also.
2193 * Note: this works for group members as well as group leaders
2194 * since the non-leader members' sibling_lists will be empty.
2196 static void __perf_event_mark_enabled(struct perf_event *event)
2198 struct perf_event *sub;
2199 u64 tstamp = perf_event_time(event);
2201 event->state = PERF_EVENT_STATE_INACTIVE;
2202 event->tstamp_enabled = tstamp - event->total_time_enabled;
2203 list_for_each_entry(sub, &event->sibling_list, group_entry) {
2204 if (sub->state >= PERF_EVENT_STATE_INACTIVE)
2205 sub->tstamp_enabled = tstamp - sub->total_time_enabled;
2210 * Cross CPU call to enable a performance event
2212 static void __perf_event_enable(struct perf_event *event,
2213 struct perf_cpu_context *cpuctx,
2214 struct perf_event_context *ctx,
2217 struct perf_event *leader = event->group_leader;
2218 struct perf_event_context *task_ctx;
2220 if (event->state >= PERF_EVENT_STATE_INACTIVE ||
2221 event->state <= PERF_EVENT_STATE_ERROR)
2224 update_context_time(ctx);
2225 __perf_event_mark_enabled(event);
2227 if (!ctx->is_active)
2230 if (!event_filter_match(event)) {
2231 if (is_cgroup_event(event)) {
2232 perf_cgroup_set_timestamp(current, ctx); // XXX ?
2233 perf_cgroup_defer_enabled(event);
2239 * If the event is in a group and isn't the group leader,
2240 * then don't put it on unless the group is on.
2242 if (leader != event && leader->state != PERF_EVENT_STATE_ACTIVE)
2245 task_ctx = cpuctx->task_ctx;
2247 WARN_ON_ONCE(task_ctx != ctx);
2249 ctx_resched(cpuctx, task_ctx);
2255 * If event->ctx is a cloned context, callers must make sure that
2256 * every task struct that event->ctx->task could possibly point to
2257 * remains valid. This condition is satisfied when called through
2258 * perf_event_for_each_child or perf_event_for_each as described
2259 * for perf_event_disable.
2261 static void _perf_event_enable(struct perf_event *event)
2263 struct perf_event_context *ctx = event->ctx;
2265 raw_spin_lock_irq(&ctx->lock);
2266 if (event->state >= PERF_EVENT_STATE_INACTIVE ||
2267 event->state < PERF_EVENT_STATE_ERROR) {
2268 raw_spin_unlock_irq(&ctx->lock);
2273 * If the event is in error state, clear that first.
2275 * That way, if we see the event in error state below, we know that it
2276 * has gone back into error state, as distinct from the task having
2277 * been scheduled away before the cross-call arrived.
2279 if (event->state == PERF_EVENT_STATE_ERROR)
2280 event->state = PERF_EVENT_STATE_OFF;
2281 raw_spin_unlock_irq(&ctx->lock);
2283 event_function_call(event, __perf_event_enable, NULL);
2287 * See perf_event_disable();
2289 void perf_event_enable(struct perf_event *event)
2291 struct perf_event_context *ctx;
2293 ctx = perf_event_ctx_lock(event);
2294 _perf_event_enable(event);
2295 perf_event_ctx_unlock(event, ctx);
2297 EXPORT_SYMBOL_GPL(perf_event_enable);
2299 static int _perf_event_refresh(struct perf_event *event, int refresh)
2302 * not supported on inherited events
2304 if (event->attr.inherit || !is_sampling_event(event))
2307 atomic_add(refresh, &event->event_limit);
2308 _perf_event_enable(event);
2314 * See perf_event_disable()
2316 int perf_event_refresh(struct perf_event *event, int refresh)
2318 struct perf_event_context *ctx;
2321 ctx = perf_event_ctx_lock(event);
2322 ret = _perf_event_refresh(event, refresh);
2323 perf_event_ctx_unlock(event, ctx);
2327 EXPORT_SYMBOL_GPL(perf_event_refresh);
2329 static void ctx_sched_out(struct perf_event_context *ctx,
2330 struct perf_cpu_context *cpuctx,
2331 enum event_type_t event_type)
2333 int is_active = ctx->is_active;
2334 struct perf_event *event;
2336 lockdep_assert_held(&ctx->lock);
2338 if (likely(!ctx->nr_events)) {
2340 * See __perf_remove_from_context().
2342 WARN_ON_ONCE(ctx->is_active);
2344 WARN_ON_ONCE(cpuctx->task_ctx);
2348 ctx->is_active &= ~event_type;
2350 WARN_ON_ONCE(cpuctx->task_ctx != ctx);
2351 if (!ctx->is_active)
2352 cpuctx->task_ctx = NULL;
2355 update_context_time(ctx);
2356 update_cgrp_time_from_cpuctx(cpuctx);
2357 if (!ctx->nr_active)
2360 perf_pmu_disable(ctx->pmu);
2361 if ((is_active & EVENT_PINNED) && (event_type & EVENT_PINNED)) {
2362 list_for_each_entry(event, &ctx->pinned_groups, group_entry)
2363 group_sched_out(event, cpuctx, ctx);
2366 if ((is_active & EVENT_FLEXIBLE) && (event_type & EVENT_FLEXIBLE)) {
2367 list_for_each_entry(event, &ctx->flexible_groups, group_entry)
2368 group_sched_out(event, cpuctx, ctx);
2370 perf_pmu_enable(ctx->pmu);
2374 * Test whether two contexts are equivalent, i.e. whether they have both been
2375 * cloned from the same version of the same context.
2377 * Equivalence is measured using a generation number in the context that is
2378 * incremented on each modification to it; see unclone_ctx(), list_add_event()
2379 * and list_del_event().
2381 static int context_equiv(struct perf_event_context *ctx1,
2382 struct perf_event_context *ctx2)
2384 lockdep_assert_held(&ctx1->lock);
2385 lockdep_assert_held(&ctx2->lock);
2387 /* Pinning disables the swap optimization */
2388 if (ctx1->pin_count || ctx2->pin_count)
2391 /* If ctx1 is the parent of ctx2 */
2392 if (ctx1 == ctx2->parent_ctx && ctx1->generation == ctx2->parent_gen)
2395 /* If ctx2 is the parent of ctx1 */
2396 if (ctx1->parent_ctx == ctx2 && ctx1->parent_gen == ctx2->generation)
2400 * If ctx1 and ctx2 have the same parent; we flatten the parent
2401 * hierarchy, see perf_event_init_context().
2403 if (ctx1->parent_ctx && ctx1->parent_ctx == ctx2->parent_ctx &&
2404 ctx1->parent_gen == ctx2->parent_gen)
2411 static void __perf_event_sync_stat(struct perf_event *event,
2412 struct perf_event *next_event)
2416 if (!event->attr.inherit_stat)
2420 * Update the event value, we cannot use perf_event_read()
2421 * because we're in the middle of a context switch and have IRQs
2422 * disabled, which upsets smp_call_function_single(), however
2423 * we know the event must be on the current CPU, therefore we
2424 * don't need to use it.
2426 switch (event->state) {
2427 case PERF_EVENT_STATE_ACTIVE:
2428 event->pmu->read(event);
2431 case PERF_EVENT_STATE_INACTIVE:
2432 update_event_times(event);
2440 * In order to keep per-task stats reliable we need to flip the event
2441 * values when we flip the contexts.
2443 value = local64_read(&next_event->count);
2444 value = local64_xchg(&event->count, value);
2445 local64_set(&next_event->count, value);
2447 swap(event->total_time_enabled, next_event->total_time_enabled);
2448 swap(event->total_time_running, next_event->total_time_running);
2451 * Since we swizzled the values, update the user visible data too.
2453 perf_event_update_userpage(event);
2454 perf_event_update_userpage(next_event);
2457 static void perf_event_sync_stat(struct perf_event_context *ctx,
2458 struct perf_event_context *next_ctx)
2460 struct perf_event *event, *next_event;
2465 update_context_time(ctx);
2467 event = list_first_entry(&ctx->event_list,
2468 struct perf_event, event_entry);
2470 next_event = list_first_entry(&next_ctx->event_list,
2471 struct perf_event, event_entry);
2473 while (&event->event_entry != &ctx->event_list &&
2474 &next_event->event_entry != &next_ctx->event_list) {
2476 __perf_event_sync_stat(event, next_event);
2478 event = list_next_entry(event, event_entry);
2479 next_event = list_next_entry(next_event, event_entry);
2483 static void perf_event_context_sched_out(struct task_struct *task, int ctxn,
2484 struct task_struct *next)
2486 struct perf_event_context *ctx = task->perf_event_ctxp[ctxn];
2487 struct perf_event_context *next_ctx;
2488 struct perf_event_context *parent, *next_parent;
2489 struct perf_cpu_context *cpuctx;
2495 cpuctx = __get_cpu_context(ctx);
2496 if (!cpuctx->task_ctx)
2500 next_ctx = next->perf_event_ctxp[ctxn];
2504 parent = rcu_dereference(ctx->parent_ctx);
2505 next_parent = rcu_dereference(next_ctx->parent_ctx);
2507 /* If neither context have a parent context; they cannot be clones. */
2508 if (!parent && !next_parent)
2511 if (next_parent == ctx || next_ctx == parent || next_parent == parent) {
2513 * Looks like the two contexts are clones, so we might be
2514 * able to optimize the context switch. We lock both
2515 * contexts and check that they are clones under the
2516 * lock (including re-checking that neither has been
2517 * uncloned in the meantime). It doesn't matter which
2518 * order we take the locks because no other cpu could
2519 * be trying to lock both of these tasks.
2521 raw_spin_lock(&ctx->lock);
2522 raw_spin_lock_nested(&next_ctx->lock, SINGLE_DEPTH_NESTING);
2523 if (context_equiv(ctx, next_ctx)) {
2524 WRITE_ONCE(ctx->task, next);
2525 WRITE_ONCE(next_ctx->task, task);
2527 swap(ctx->task_ctx_data, next_ctx->task_ctx_data);
2530 * RCU_INIT_POINTER here is safe because we've not
2531 * modified the ctx and the above modification of
2532 * ctx->task and ctx->task_ctx_data are immaterial
2533 * since those values are always verified under
2534 * ctx->lock which we're now holding.
2536 RCU_INIT_POINTER(task->perf_event_ctxp[ctxn], next_ctx);
2537 RCU_INIT_POINTER(next->perf_event_ctxp[ctxn], ctx);
2541 perf_event_sync_stat(ctx, next_ctx);
2543 raw_spin_unlock(&next_ctx->lock);
2544 raw_spin_unlock(&ctx->lock);
2550 raw_spin_lock(&ctx->lock);
2551 task_ctx_sched_out(cpuctx, ctx);
2552 raw_spin_unlock(&ctx->lock);
2556 void perf_sched_cb_dec(struct pmu *pmu)
2558 this_cpu_dec(perf_sched_cb_usages);
2561 void perf_sched_cb_inc(struct pmu *pmu)
2563 this_cpu_inc(perf_sched_cb_usages);
2567 * This function provides the context switch callback to the lower code
2568 * layer. It is invoked ONLY when the context switch callback is enabled.
2570 static void perf_pmu_sched_task(struct task_struct *prev,
2571 struct task_struct *next,
2574 struct perf_cpu_context *cpuctx;
2576 unsigned long flags;
2581 local_irq_save(flags);
2585 list_for_each_entry_rcu(pmu, &pmus, entry) {
2586 if (pmu->sched_task) {
2587 cpuctx = this_cpu_ptr(pmu->pmu_cpu_context);
2589 perf_ctx_lock(cpuctx, cpuctx->task_ctx);
2591 perf_pmu_disable(pmu);
2593 pmu->sched_task(cpuctx->task_ctx, sched_in);
2595 perf_pmu_enable(pmu);
2597 perf_ctx_unlock(cpuctx, cpuctx->task_ctx);
2603 local_irq_restore(flags);
2606 static void perf_event_switch(struct task_struct *task,
2607 struct task_struct *next_prev, bool sched_in);
2609 #define for_each_task_context_nr(ctxn) \
2610 for ((ctxn) = 0; (ctxn) < perf_nr_task_contexts; (ctxn)++)
2613 * Called from scheduler to remove the events of the current task,
2614 * with interrupts disabled.
2616 * We stop each event and update the event value in event->count.
2618 * This does not protect us against NMI, but disable()
2619 * sets the disabled bit in the control field of event _before_
2620 * accessing the event control register. If a NMI hits, then it will
2621 * not restart the event.
2623 void __perf_event_task_sched_out(struct task_struct *task,
2624 struct task_struct *next)
2628 if (__this_cpu_read(perf_sched_cb_usages))
2629 perf_pmu_sched_task(task, next, false);
2631 if (atomic_read(&nr_switch_events))
2632 perf_event_switch(task, next, false);
2634 for_each_task_context_nr(ctxn)
2635 perf_event_context_sched_out(task, ctxn, next);
2638 * if cgroup events exist on this CPU, then we need
2639 * to check if we have to switch out PMU state.
2640 * cgroup event are system-wide mode only
2642 if (atomic_read(this_cpu_ptr(&perf_cgroup_events)))
2643 perf_cgroup_sched_out(task, next);
2646 static void task_ctx_sched_out(struct perf_cpu_context *cpuctx,
2647 struct perf_event_context *ctx)
2649 if (!cpuctx->task_ctx)
2652 if (WARN_ON_ONCE(ctx != cpuctx->task_ctx))
2655 ctx_sched_out(ctx, cpuctx, EVENT_ALL);
2659 * Called with IRQs disabled
2661 static void cpu_ctx_sched_out(struct perf_cpu_context *cpuctx,
2662 enum event_type_t event_type)
2664 ctx_sched_out(&cpuctx->ctx, cpuctx, event_type);
2668 ctx_pinned_sched_in(struct perf_event_context *ctx,
2669 struct perf_cpu_context *cpuctx)
2671 struct perf_event *event;
2673 list_for_each_entry(event, &ctx->pinned_groups, group_entry) {
2674 if (event->state <= PERF_EVENT_STATE_OFF)
2676 if (!event_filter_match(event))
2679 /* may need to reset tstamp_enabled */
2680 if (is_cgroup_event(event))
2681 perf_cgroup_mark_enabled(event, ctx);
2683 if (group_can_go_on(event, cpuctx, 1))
2684 group_sched_in(event, cpuctx, ctx);
2687 * If this pinned group hasn't been scheduled,
2688 * put it in error state.
2690 if (event->state == PERF_EVENT_STATE_INACTIVE) {
2691 update_group_times(event);
2692 event->state = PERF_EVENT_STATE_ERROR;
2698 ctx_flexible_sched_in(struct perf_event_context *ctx,
2699 struct perf_cpu_context *cpuctx)
2701 struct perf_event *event;
2704 list_for_each_entry(event, &ctx->flexible_groups, group_entry) {
2705 /* Ignore events in OFF or ERROR state */
2706 if (event->state <= PERF_EVENT_STATE_OFF)
2709 * Listen to the 'cpu' scheduling filter constraint
2712 if (!event_filter_match(event))
2715 /* may need to reset tstamp_enabled */
2716 if (is_cgroup_event(event))
2717 perf_cgroup_mark_enabled(event, ctx);
2719 if (group_can_go_on(event, cpuctx, can_add_hw)) {
2720 if (group_sched_in(event, cpuctx, ctx))
2727 ctx_sched_in(struct perf_event_context *ctx,
2728 struct perf_cpu_context *cpuctx,
2729 enum event_type_t event_type,
2730 struct task_struct *task)
2732 int is_active = ctx->is_active;
2735 lockdep_assert_held(&ctx->lock);
2737 if (likely(!ctx->nr_events))
2740 ctx->is_active |= event_type;
2743 cpuctx->task_ctx = ctx;
2745 WARN_ON_ONCE(cpuctx->task_ctx != ctx);
2749 ctx->timestamp = now;
2750 perf_cgroup_set_timestamp(task, ctx);
2752 * First go through the list and put on any pinned groups
2753 * in order to give them the best chance of going on.
2755 if (!(is_active & EVENT_PINNED) && (event_type & EVENT_PINNED))
2756 ctx_pinned_sched_in(ctx, cpuctx);
2758 /* Then walk through the lower prio flexible groups */
2759 if (!(is_active & EVENT_FLEXIBLE) && (event_type & EVENT_FLEXIBLE))
2760 ctx_flexible_sched_in(ctx, cpuctx);
2763 static void cpu_ctx_sched_in(struct perf_cpu_context *cpuctx,
2764 enum event_type_t event_type,
2765 struct task_struct *task)
2767 struct perf_event_context *ctx = &cpuctx->ctx;
2769 ctx_sched_in(ctx, cpuctx, event_type, task);
2772 static void perf_event_context_sched_in(struct perf_event_context *ctx,
2773 struct task_struct *task)
2775 struct perf_cpu_context *cpuctx;
2777 cpuctx = __get_cpu_context(ctx);
2778 if (cpuctx->task_ctx == ctx)
2781 perf_ctx_lock(cpuctx, ctx);
2782 perf_pmu_disable(ctx->pmu);
2784 * We want to keep the following priority order:
2785 * cpu pinned (that don't need to move), task pinned,
2786 * cpu flexible, task flexible.
2788 cpu_ctx_sched_out(cpuctx, EVENT_FLEXIBLE);
2789 perf_event_sched_in(cpuctx, ctx, task);
2790 perf_pmu_enable(ctx->pmu);
2791 perf_ctx_unlock(cpuctx, ctx);
2795 * Called from scheduler to add the events of the current task
2796 * with interrupts disabled.
2798 * We restore the event value and then enable it.
2800 * This does not protect us against NMI, but enable()
2801 * sets the enabled bit in the control field of event _before_
2802 * accessing the event control register. If a NMI hits, then it will
2803 * keep the event running.
2805 void __perf_event_task_sched_in(struct task_struct *prev,
2806 struct task_struct *task)
2808 struct perf_event_context *ctx;
2812 * If cgroup events exist on this CPU, then we need to check if we have
2813 * to switch in PMU state; cgroup event are system-wide mode only.
2815 * Since cgroup events are CPU events, we must schedule these in before
2816 * we schedule in the task events.
2818 if (atomic_read(this_cpu_ptr(&perf_cgroup_events)))
2819 perf_cgroup_sched_in(prev, task);
2821 for_each_task_context_nr(ctxn) {
2822 ctx = task->perf_event_ctxp[ctxn];
2826 perf_event_context_sched_in(ctx, task);
2829 if (atomic_read(&nr_switch_events))
2830 perf_event_switch(task, prev, true);
2832 if (__this_cpu_read(perf_sched_cb_usages))
2833 perf_pmu_sched_task(prev, task, true);
2836 static u64 perf_calculate_period(struct perf_event *event, u64 nsec, u64 count)
2838 u64 frequency = event->attr.sample_freq;
2839 u64 sec = NSEC_PER_SEC;
2840 u64 divisor, dividend;
2842 int count_fls, nsec_fls, frequency_fls, sec_fls;
2844 count_fls = fls64(count);
2845 nsec_fls = fls64(nsec);
2846 frequency_fls = fls64(frequency);
2850 * We got @count in @nsec, with a target of sample_freq HZ
2851 * the target period becomes:
2854 * period = -------------------
2855 * @nsec * sample_freq
2860 * Reduce accuracy by one bit such that @a and @b converge
2861 * to a similar magnitude.
2863 #define REDUCE_FLS(a, b) \
2865 if (a##_fls > b##_fls) { \
2875 * Reduce accuracy until either term fits in a u64, then proceed with
2876 * the other, so that finally we can do a u64/u64 division.
2878 while (count_fls + sec_fls > 64 && nsec_fls + frequency_fls > 64) {
2879 REDUCE_FLS(nsec, frequency);
2880 REDUCE_FLS(sec, count);
2883 if (count_fls + sec_fls > 64) {
2884 divisor = nsec * frequency;
2886 while (count_fls + sec_fls > 64) {
2887 REDUCE_FLS(count, sec);
2891 dividend = count * sec;
2893 dividend = count * sec;
2895 while (nsec_fls + frequency_fls > 64) {
2896 REDUCE_FLS(nsec, frequency);
2900 divisor = nsec * frequency;
2906 return div64_u64(dividend, divisor);
2909 static DEFINE_PER_CPU(int, perf_throttled_count);
2910 static DEFINE_PER_CPU(u64, perf_throttled_seq);
2912 static void perf_adjust_period(struct perf_event *event, u64 nsec, u64 count, bool disable)
2914 struct hw_perf_event *hwc = &event->hw;
2915 s64 period, sample_period;
2918 period = perf_calculate_period(event, nsec, count);
2920 delta = (s64)(period - hwc->sample_period);
2921 delta = (delta + 7) / 8; /* low pass filter */
2923 sample_period = hwc->sample_period + delta;
2928 hwc->sample_period = sample_period;
2930 if (local64_read(&hwc->period_left) > 8*sample_period) {
2932 event->pmu->stop(event, PERF_EF_UPDATE);
2934 local64_set(&hwc->period_left, 0);
2937 event->pmu->start(event, PERF_EF_RELOAD);
2942 * combine freq adjustment with unthrottling to avoid two passes over the
2943 * events. At the same time, make sure, having freq events does not change
2944 * the rate of unthrottling as that would introduce bias.
2946 static void perf_adjust_freq_unthr_context(struct perf_event_context *ctx,
2949 struct perf_event *event;
2950 struct hw_perf_event *hwc;
2951 u64 now, period = TICK_NSEC;
2955 * only need to iterate over all events iff:
2956 * - context have events in frequency mode (needs freq adjust)
2957 * - there are events to unthrottle on this cpu
2959 if (!(ctx->nr_freq || needs_unthr))
2962 raw_spin_lock(&ctx->lock);
2963 perf_pmu_disable(ctx->pmu);
2965 list_for_each_entry_rcu(event, &ctx->event_list, event_entry) {
2966 if (event->state != PERF_EVENT_STATE_ACTIVE)
2969 if (!event_filter_match(event))
2972 perf_pmu_disable(event->pmu);
2976 if (hwc->interrupts == MAX_INTERRUPTS) {
2977 hwc->interrupts = 0;
2978 perf_log_throttle(event, 1);
2979 event->pmu->start(event, 0);
2982 if (!event->attr.freq || !event->attr.sample_freq)
2986 * stop the event and update event->count
2988 event->pmu->stop(event, PERF_EF_UPDATE);
2990 now = local64_read(&event->count);
2991 delta = now - hwc->freq_count_stamp;
2992 hwc->freq_count_stamp = now;
2996 * reload only if value has changed
2997 * we have stopped the event so tell that
2998 * to perf_adjust_period() to avoid stopping it
3002 perf_adjust_period(event, period, delta, false);
3004 event->pmu->start(event, delta > 0 ? PERF_EF_RELOAD : 0);
3006 perf_pmu_enable(event->pmu);
3009 perf_pmu_enable(ctx->pmu);
3010 raw_spin_unlock(&ctx->lock);
3014 * Round-robin a context's events:
3016 static void rotate_ctx(struct perf_event_context *ctx)
3019 * Rotate the first entry last of non-pinned groups. Rotation might be
3020 * disabled by the inheritance code.
3022 if (!ctx->rotate_disable)
3023 list_rotate_left(&ctx->flexible_groups);
3026 static int perf_rotate_context(struct perf_cpu_context *cpuctx)
3028 struct perf_event_context *ctx = NULL;
3031 if (cpuctx->ctx.nr_events) {
3032 if (cpuctx->ctx.nr_events != cpuctx->ctx.nr_active)
3036 ctx = cpuctx->task_ctx;
3037 if (ctx && ctx->nr_events) {
3038 if (ctx->nr_events != ctx->nr_active)
3045 perf_ctx_lock(cpuctx, cpuctx->task_ctx);
3046 perf_pmu_disable(cpuctx->ctx.pmu);
3048 cpu_ctx_sched_out(cpuctx, EVENT_FLEXIBLE);
3050 ctx_sched_out(ctx, cpuctx, EVENT_FLEXIBLE);
3052 rotate_ctx(&cpuctx->ctx);
3056 perf_event_sched_in(cpuctx, ctx, current);
3058 perf_pmu_enable(cpuctx->ctx.pmu);
3059 perf_ctx_unlock(cpuctx, cpuctx->task_ctx);
3065 #ifdef CONFIG_NO_HZ_FULL
3066 bool perf_event_can_stop_tick(void)
3068 if (atomic_read(&nr_freq_events) ||
3069 __this_cpu_read(perf_throttled_count))
3076 void perf_event_task_tick(void)
3078 struct list_head *head = this_cpu_ptr(&active_ctx_list);
3079 struct perf_event_context *ctx, *tmp;
3082 WARN_ON(!irqs_disabled());
3084 __this_cpu_inc(perf_throttled_seq);
3085 throttled = __this_cpu_xchg(perf_throttled_count, 0);
3087 list_for_each_entry_safe(ctx, tmp, head, active_ctx_list)
3088 perf_adjust_freq_unthr_context(ctx, throttled);
3091 static int event_enable_on_exec(struct perf_event *event,
3092 struct perf_event_context *ctx)
3094 if (!event->attr.enable_on_exec)
3097 event->attr.enable_on_exec = 0;
3098 if (event->state >= PERF_EVENT_STATE_INACTIVE)
3101 __perf_event_mark_enabled(event);
3107 * Enable all of a task's events that have been marked enable-on-exec.
3108 * This expects task == current.
3110 static void perf_event_enable_on_exec(int ctxn)
3112 struct perf_event_context *ctx, *clone_ctx = NULL;
3113 struct perf_cpu_context *cpuctx;
3114 struct perf_event *event;
3115 unsigned long flags;
3118 local_irq_save(flags);
3119 ctx = current->perf_event_ctxp[ctxn];
3120 if (!ctx || !ctx->nr_events)
3123 cpuctx = __get_cpu_context(ctx);
3124 perf_ctx_lock(cpuctx, ctx);
3125 list_for_each_entry(event, &ctx->event_list, event_entry)
3126 enabled |= event_enable_on_exec(event, ctx);
3129 * Unclone and reschedule this context if we enabled any event.
3132 clone_ctx = unclone_ctx(ctx);
3133 ctx_resched(cpuctx, ctx);
3135 perf_ctx_unlock(cpuctx, ctx);
3138 local_irq_restore(flags);
3144 void perf_event_exec(void)
3149 for_each_task_context_nr(ctxn)
3150 perf_event_enable_on_exec(ctxn);
3154 struct perf_read_data {
3155 struct perf_event *event;
3161 * Cross CPU call to read the hardware event
3163 static void __perf_event_read(void *info)
3165 struct perf_read_data *data = info;
3166 struct perf_event *sub, *event = data->event;
3167 struct perf_event_context *ctx = event->ctx;
3168 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
3169 struct pmu *pmu = event->pmu;
3172 * If this is a task context, we need to check whether it is
3173 * the current task context of this cpu. If not it has been
3174 * scheduled out before the smp call arrived. In that case
3175 * event->count would have been updated to a recent sample
3176 * when the event was scheduled out.
3178 if (ctx->task && cpuctx->task_ctx != ctx)
3181 raw_spin_lock(&ctx->lock);
3182 if (ctx->is_active) {
3183 update_context_time(ctx);
3184 update_cgrp_time_from_event(event);
3187 update_event_times(event);
3188 if (event->state != PERF_EVENT_STATE_ACTIVE)
3197 pmu->start_txn(pmu, PERF_PMU_TXN_READ);
3201 list_for_each_entry(sub, &event->sibling_list, group_entry) {
3202 update_event_times(sub);
3203 if (sub->state == PERF_EVENT_STATE_ACTIVE) {
3205 * Use sibling's PMU rather than @event's since
3206 * sibling could be on different (eg: software) PMU.
3208 sub->pmu->read(sub);
3212 data->ret = pmu->commit_txn(pmu);
3215 raw_spin_unlock(&ctx->lock);
3218 static inline u64 perf_event_count(struct perf_event *event)
3220 if (event->pmu->count)
3221 return event->pmu->count(event);
3223 return __perf_event_count(event);
3227 * NMI-safe method to read a local event, that is an event that
3229 * - either for the current task, or for this CPU
3230 * - does not have inherit set, for inherited task events
3231 * will not be local and we cannot read them atomically
3232 * - must not have a pmu::count method
3234 u64 perf_event_read_local(struct perf_event *event)
3236 unsigned long flags;
3240 * Disabling interrupts avoids all counter scheduling (context
3241 * switches, timer based rotation and IPIs).
3243 local_irq_save(flags);
3245 /* If this is a per-task event, it must be for current */
3246 WARN_ON_ONCE((event->attach_state & PERF_ATTACH_TASK) &&
3247 event->hw.target != current);
3249 /* If this is a per-CPU event, it must be for this CPU */
3250 WARN_ON_ONCE(!(event->attach_state & PERF_ATTACH_TASK) &&
3251 event->cpu != smp_processor_id());
3254 * It must not be an event with inherit set, we cannot read
3255 * all child counters from atomic context.
3257 WARN_ON_ONCE(event->attr.inherit);
3260 * It must not have a pmu::count method, those are not
3263 WARN_ON_ONCE(event->pmu->count);
3266 * If the event is currently on this CPU, its either a per-task event,
3267 * or local to this CPU. Furthermore it means its ACTIVE (otherwise
3270 if (event->oncpu == smp_processor_id())
3271 event->pmu->read(event);
3273 val = local64_read(&event->count);
3274 local_irq_restore(flags);
3279 static int perf_event_read(struct perf_event *event, bool group)
3284 * If event is enabled and currently active on a CPU, update the
3285 * value in the event structure:
3287 if (event->state == PERF_EVENT_STATE_ACTIVE) {
3288 struct perf_read_data data = {
3293 smp_call_function_single(event->oncpu,
3294 __perf_event_read, &data, 1);
3296 } else if (event->state == PERF_EVENT_STATE_INACTIVE) {
3297 struct perf_event_context *ctx = event->ctx;
3298 unsigned long flags;
3300 raw_spin_lock_irqsave(&ctx->lock, flags);
3302 * may read while context is not active
3303 * (e.g., thread is blocked), in that case
3304 * we cannot update context time
3306 if (ctx->is_active) {
3307 update_context_time(ctx);
3308 update_cgrp_time_from_event(event);
3311 update_group_times(event);
3313 update_event_times(event);
3314 raw_spin_unlock_irqrestore(&ctx->lock, flags);
3321 * Initialize the perf_event context in a task_struct:
3323 static void __perf_event_init_context(struct perf_event_context *ctx)
3325 raw_spin_lock_init(&ctx->lock);
3326 mutex_init(&ctx->mutex);
3327 INIT_LIST_HEAD(&ctx->active_ctx_list);
3328 INIT_LIST_HEAD(&ctx->pinned_groups);
3329 INIT_LIST_HEAD(&ctx->flexible_groups);
3330 INIT_LIST_HEAD(&ctx->event_list);
3331 atomic_set(&ctx->refcount, 1);
3334 static struct perf_event_context *
3335 alloc_perf_context(struct pmu *pmu, struct task_struct *task)
3337 struct perf_event_context *ctx;
3339 ctx = kzalloc(sizeof(struct perf_event_context), GFP_KERNEL);
3343 __perf_event_init_context(ctx);
3346 get_task_struct(task);
3353 static struct task_struct *
3354 find_lively_task_by_vpid(pid_t vpid)
3356 struct task_struct *task;
3363 task = find_task_by_vpid(vpid);
3365 get_task_struct(task);
3369 return ERR_PTR(-ESRCH);
3371 /* Reuse ptrace permission checks for now. */
3373 if (!ptrace_may_access(task, PTRACE_MODE_READ_REALCREDS))
3378 put_task_struct(task);
3379 return ERR_PTR(err);
3384 * Returns a matching context with refcount and pincount.
3386 static struct perf_event_context *
3387 find_get_context(struct pmu *pmu, struct task_struct *task,
3388 struct perf_event *event)
3390 struct perf_event_context *ctx, *clone_ctx = NULL;
3391 struct perf_cpu_context *cpuctx;
3392 void *task_ctx_data = NULL;
3393 unsigned long flags;
3395 int cpu = event->cpu;
3398 /* Must be root to operate on a CPU event: */
3399 if (perf_paranoid_cpu() && !capable(CAP_SYS_ADMIN))
3400 return ERR_PTR(-EACCES);
3403 * We could be clever and allow to attach a event to an
3404 * offline CPU and activate it when the CPU comes up, but
3407 if (!cpu_online(cpu))
3408 return ERR_PTR(-ENODEV);
3410 cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
3419 ctxn = pmu->task_ctx_nr;
3423 if (event->attach_state & PERF_ATTACH_TASK_DATA) {
3424 task_ctx_data = kzalloc(pmu->task_ctx_size, GFP_KERNEL);
3425 if (!task_ctx_data) {
3432 ctx = perf_lock_task_context(task, ctxn, &flags);
3434 clone_ctx = unclone_ctx(ctx);
3437 if (task_ctx_data && !ctx->task_ctx_data) {
3438 ctx->task_ctx_data = task_ctx_data;
3439 task_ctx_data = NULL;
3441 raw_spin_unlock_irqrestore(&ctx->lock, flags);
3446 ctx = alloc_perf_context(pmu, task);
3451 if (task_ctx_data) {
3452 ctx->task_ctx_data = task_ctx_data;
3453 task_ctx_data = NULL;
3457 mutex_lock(&task->perf_event_mutex);
3459 * If it has already passed perf_event_exit_task().
3460 * we must see PF_EXITING, it takes this mutex too.
3462 if (task->flags & PF_EXITING)
3464 else if (task->perf_event_ctxp[ctxn])
3469 rcu_assign_pointer(task->perf_event_ctxp[ctxn], ctx);
3471 mutex_unlock(&task->perf_event_mutex);
3473 if (unlikely(err)) {
3482 kfree(task_ctx_data);
3486 kfree(task_ctx_data);
3487 return ERR_PTR(err);
3490 static void perf_event_free_filter(struct perf_event *event);
3491 static void perf_event_free_bpf_prog(struct perf_event *event);
3493 static void free_event_rcu(struct rcu_head *head)
3495 struct perf_event *event;
3497 event = container_of(head, struct perf_event, rcu_head);
3499 put_pid_ns(event->ns);
3500 perf_event_free_filter(event);
3504 static void ring_buffer_attach(struct perf_event *event,
3505 struct ring_buffer *rb);
3507 static void unaccount_event_cpu(struct perf_event *event, int cpu)
3512 if (is_cgroup_event(event))
3513 atomic_dec(&per_cpu(perf_cgroup_events, cpu));
3516 static void unaccount_event(struct perf_event *event)
3523 if (event->attach_state & PERF_ATTACH_TASK)
3525 if (event->attr.mmap || event->attr.mmap_data)
3526 atomic_dec(&nr_mmap_events);
3527 if (event->attr.comm)
3528 atomic_dec(&nr_comm_events);
3529 if (event->attr.task)
3530 atomic_dec(&nr_task_events);
3531 if (event->attr.freq)
3532 atomic_dec(&nr_freq_events);
3533 if (event->attr.context_switch) {
3535 atomic_dec(&nr_switch_events);
3537 if (is_cgroup_event(event))
3539 if (has_branch_stack(event))
3543 static_key_slow_dec_deferred(&perf_sched_events);
3545 unaccount_event_cpu(event, event->cpu);
3549 * The following implement mutual exclusion of events on "exclusive" pmus
3550 * (PERF_PMU_CAP_EXCLUSIVE). Such pmus can only have one event scheduled
3551 * at a time, so we disallow creating events that might conflict, namely:
3553 * 1) cpu-wide events in the presence of per-task events,
3554 * 2) per-task events in the presence of cpu-wide events,
3555 * 3) two matching events on the same context.
3557 * The former two cases are handled in the allocation path (perf_event_alloc(),
3558 * _free_event()), the latter -- before the first perf_install_in_context().
3560 static int exclusive_event_init(struct perf_event *event)
3562 struct pmu *pmu = event->pmu;
3564 if (!(pmu->capabilities & PERF_PMU_CAP_EXCLUSIVE))
3568 * Prevent co-existence of per-task and cpu-wide events on the
3569 * same exclusive pmu.
3571 * Negative pmu::exclusive_cnt means there are cpu-wide
3572 * events on this "exclusive" pmu, positive means there are
3575 * Since this is called in perf_event_alloc() path, event::ctx
3576 * doesn't exist yet; it is, however, safe to use PERF_ATTACH_TASK
3577 * to mean "per-task event", because unlike other attach states it
3578 * never gets cleared.
3580 if (event->attach_state & PERF_ATTACH_TASK) {
3581 if (!atomic_inc_unless_negative(&pmu->exclusive_cnt))
3584 if (!atomic_dec_unless_positive(&pmu->exclusive_cnt))
3591 static void exclusive_event_destroy(struct perf_event *event)
3593 struct pmu *pmu = event->pmu;
3595 if (!(pmu->capabilities & PERF_PMU_CAP_EXCLUSIVE))
3598 /* see comment in exclusive_event_init() */
3599 if (event->attach_state & PERF_ATTACH_TASK)
3600 atomic_dec(&pmu->exclusive_cnt);
3602 atomic_inc(&pmu->exclusive_cnt);
3605 static bool exclusive_event_match(struct perf_event *e1, struct perf_event *e2)
3607 if ((e1->pmu->capabilities & PERF_PMU_CAP_EXCLUSIVE) &&
3608 (e1->cpu == e2->cpu ||
3615 /* Called under the same ctx::mutex as perf_install_in_context() */
3616 static bool exclusive_event_installable(struct perf_event *event,
3617 struct perf_event_context *ctx)
3619 struct perf_event *iter_event;
3620 struct pmu *pmu = event->pmu;
3622 if (!(pmu->capabilities & PERF_PMU_CAP_EXCLUSIVE))
3625 list_for_each_entry(iter_event, &ctx->event_list, event_entry) {
3626 if (exclusive_event_match(iter_event, event))
3633 static void _free_event(struct perf_event *event)
3635 irq_work_sync(&event->pending);
3637 unaccount_event(event);
3641 * Can happen when we close an event with re-directed output.
3643 * Since we have a 0 refcount, perf_mmap_close() will skip
3644 * over us; possibly making our ring_buffer_put() the last.
3646 mutex_lock(&event->mmap_mutex);
3647 ring_buffer_attach(event, NULL);
3648 mutex_unlock(&event->mmap_mutex);
3651 if (is_cgroup_event(event))
3652 perf_detach_cgroup(event);
3654 if (!event->parent) {
3655 if (event->attr.sample_type & PERF_SAMPLE_CALLCHAIN)
3656 put_callchain_buffers();
3659 perf_event_free_bpf_prog(event);
3662 event->destroy(event);
3665 put_ctx(event->ctx);
3668 exclusive_event_destroy(event);
3669 module_put(event->pmu->module);
3672 call_rcu(&event->rcu_head, free_event_rcu);
3676 * Used to free events which have a known refcount of 1, such as in error paths
3677 * where the event isn't exposed yet and inherited events.
3679 static void free_event(struct perf_event *event)
3681 if (WARN(atomic_long_cmpxchg(&event->refcount, 1, 0) != 1,
3682 "unexpected event refcount: %ld; ptr=%p\n",
3683 atomic_long_read(&event->refcount), event)) {
3684 /* leak to avoid use-after-free */
3692 * Remove user event from the owner task.
3694 static void perf_remove_from_owner(struct perf_event *event)
3696 struct task_struct *owner;
3700 * Matches the smp_store_release() in perf_event_exit_task(). If we
3701 * observe !owner it means the list deletion is complete and we can
3702 * indeed free this event, otherwise we need to serialize on
3703 * owner->perf_event_mutex.
3705 owner = lockless_dereference(event->owner);
3708 * Since delayed_put_task_struct() also drops the last
3709 * task reference we can safely take a new reference
3710 * while holding the rcu_read_lock().
3712 get_task_struct(owner);
3718 * If we're here through perf_event_exit_task() we're already
3719 * holding ctx->mutex which would be an inversion wrt. the
3720 * normal lock order.
3722 * However we can safely take this lock because its the child
3725 mutex_lock_nested(&owner->perf_event_mutex, SINGLE_DEPTH_NESTING);
3728 * We have to re-check the event->owner field, if it is cleared
3729 * we raced with perf_event_exit_task(), acquiring the mutex
3730 * ensured they're done, and we can proceed with freeing the
3734 list_del_init(&event->owner_entry);
3735 smp_store_release(&event->owner, NULL);
3737 mutex_unlock(&owner->perf_event_mutex);
3738 put_task_struct(owner);
3742 static void put_event(struct perf_event *event)
3744 if (!atomic_long_dec_and_test(&event->refcount))
3751 * Kill an event dead; while event:refcount will preserve the event
3752 * object, it will not preserve its functionality. Once the last 'user'
3753 * gives up the object, we'll destroy the thing.
3755 int perf_event_release_kernel(struct perf_event *event)
3757 struct perf_event_context *ctx = event->ctx;
3758 struct perf_event *child, *tmp;
3761 * If we got here through err_file: fput(event_file); we will not have
3762 * attached to a context yet.
3765 WARN_ON_ONCE(event->attach_state &
3766 (PERF_ATTACH_CONTEXT|PERF_ATTACH_GROUP));
3770 if (!is_kernel_event(event))
3771 perf_remove_from_owner(event);
3773 ctx = perf_event_ctx_lock(event);
3774 WARN_ON_ONCE(ctx->parent_ctx);
3775 perf_remove_from_context(event, DETACH_GROUP | DETACH_STATE);
3776 perf_event_ctx_unlock(event, ctx);
3779 * At this point we must have event->state == PERF_EVENT_STATE_EXIT,
3780 * either from the above perf_remove_from_context() or through
3781 * perf_event_exit_event().
3783 * Therefore, anybody acquiring event->child_mutex after the below
3784 * loop _must_ also see this, most importantly inherit_event() which
3785 * will avoid placing more children on the list.
3787 * Thus this guarantees that we will in fact observe and kill _ALL_
3790 WARN_ON_ONCE(event->state != PERF_EVENT_STATE_EXIT);
3793 mutex_lock(&event->child_mutex);
3794 list_for_each_entry(child, &event->child_list, child_list) {
3797 * Cannot change, child events are not migrated, see the
3798 * comment with perf_event_ctx_lock_nested().
3800 ctx = lockless_dereference(child->ctx);
3802 * Since child_mutex nests inside ctx::mutex, we must jump
3803 * through hoops. We start by grabbing a reference on the ctx.
3805 * Since the event cannot get freed while we hold the
3806 * child_mutex, the context must also exist and have a !0
3812 * Now that we have a ctx ref, we can drop child_mutex, and
3813 * acquire ctx::mutex without fear of it going away. Then we
3814 * can re-acquire child_mutex.
3816 mutex_unlock(&event->child_mutex);
3817 mutex_lock(&ctx->mutex);
3818 mutex_lock(&event->child_mutex);
3821 * Now that we hold ctx::mutex and child_mutex, revalidate our
3822 * state, if child is still the first entry, it didn't get freed
3823 * and we can continue doing so.
3825 tmp = list_first_entry_or_null(&event->child_list,
3826 struct perf_event, child_list);
3828 perf_remove_from_context(child, DETACH_GROUP);
3829 list_del(&child->child_list);
3832 * This matches the refcount bump in inherit_event();
3833 * this can't be the last reference.
3838 mutex_unlock(&event->child_mutex);
3839 mutex_unlock(&ctx->mutex);
3843 mutex_unlock(&event->child_mutex);
3846 put_event(event); /* Must be the 'last' reference */
3849 EXPORT_SYMBOL_GPL(perf_event_release_kernel);
3852 * Called when the last reference to the file is gone.
3854 static int perf_release(struct inode *inode, struct file *file)
3856 perf_event_release_kernel(file->private_data);
3860 u64 perf_event_read_value(struct perf_event *event, u64 *enabled, u64 *running)
3862 struct perf_event *child;
3868 mutex_lock(&event->child_mutex);
3870 (void)perf_event_read(event, false);
3871 total += perf_event_count(event);
3873 *enabled += event->total_time_enabled +
3874 atomic64_read(&event->child_total_time_enabled);
3875 *running += event->total_time_running +
3876 atomic64_read(&event->child_total_time_running);
3878 list_for_each_entry(child, &event->child_list, child_list) {
3879 (void)perf_event_read(child, false);
3880 total += perf_event_count(child);
3881 *enabled += child->total_time_enabled;
3882 *running += child->total_time_running;
3884 mutex_unlock(&event->child_mutex);
3888 EXPORT_SYMBOL_GPL(perf_event_read_value);
3890 static int __perf_read_group_add(struct perf_event *leader,
3891 u64 read_format, u64 *values)
3893 struct perf_event *sub;
3894 int n = 1; /* skip @nr */
3897 ret = perf_event_read(leader, true);
3902 * Since we co-schedule groups, {enabled,running} times of siblings
3903 * will be identical to those of the leader, so we only publish one
3906 if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED) {
3907 values[n++] += leader->total_time_enabled +
3908 atomic64_read(&leader->child_total_time_enabled);
3911 if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING) {
3912 values[n++] += leader->total_time_running +
3913 atomic64_read(&leader->child_total_time_running);
3917 * Write {count,id} tuples for every sibling.
3919 values[n++] += perf_event_count(leader);
3920 if (read_format & PERF_FORMAT_ID)
3921 values[n++] = primary_event_id(leader);
3923 list_for_each_entry(sub, &leader->sibling_list, group_entry) {
3924 values[n++] += perf_event_count(sub);
3925 if (read_format & PERF_FORMAT_ID)
3926 values[n++] = primary_event_id(sub);
3932 static int perf_read_group(struct perf_event *event,
3933 u64 read_format, char __user *buf)
3935 struct perf_event *leader = event->group_leader, *child;
3936 struct perf_event_context *ctx = leader->ctx;
3940 lockdep_assert_held(&ctx->mutex);
3942 values = kzalloc(event->read_size, GFP_KERNEL);
3946 values[0] = 1 + leader->nr_siblings;
3949 * By locking the child_mutex of the leader we effectively
3950 * lock the child list of all siblings.. XXX explain how.
3952 mutex_lock(&leader->child_mutex);
3954 ret = __perf_read_group_add(leader, read_format, values);
3958 list_for_each_entry(child, &leader->child_list, child_list) {
3959 ret = __perf_read_group_add(child, read_format, values);
3964 mutex_unlock(&leader->child_mutex);
3966 ret = event->read_size;
3967 if (copy_to_user(buf, values, event->read_size))
3972 mutex_unlock(&leader->child_mutex);
3978 static int perf_read_one(struct perf_event *event,
3979 u64 read_format, char __user *buf)
3981 u64 enabled, running;
3985 values[n++] = perf_event_read_value(event, &enabled, &running);
3986 if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED)
3987 values[n++] = enabled;
3988 if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING)
3989 values[n++] = running;
3990 if (read_format & PERF_FORMAT_ID)
3991 values[n++] = primary_event_id(event);
3993 if (copy_to_user(buf, values, n * sizeof(u64)))
3996 return n * sizeof(u64);
3999 static bool is_event_hup(struct perf_event *event)
4003 if (event->state != PERF_EVENT_STATE_EXIT)
4006 mutex_lock(&event->child_mutex);
4007 no_children = list_empty(&event->child_list);
4008 mutex_unlock(&event->child_mutex);
4013 * Read the performance event - simple non blocking version for now
4016 __perf_read(struct perf_event *event, char __user *buf, size_t count)
4018 u64 read_format = event->attr.read_format;
4022 * Return end-of-file for a read on a event that is in
4023 * error state (i.e. because it was pinned but it couldn't be
4024 * scheduled on to the CPU at some point).
4026 if (event->state == PERF_EVENT_STATE_ERROR)
4029 if (count < event->read_size)
4032 WARN_ON_ONCE(event->ctx->parent_ctx);
4033 if (read_format & PERF_FORMAT_GROUP)
4034 ret = perf_read_group(event, read_format, buf);
4036 ret = perf_read_one(event, read_format, buf);
4042 perf_read(struct file *file, char __user *buf, size_t count, loff_t *ppos)
4044 struct perf_event *event = file->private_data;
4045 struct perf_event_context *ctx;
4048 ctx = perf_event_ctx_lock(event);
4049 ret = __perf_read(event, buf, count);
4050 perf_event_ctx_unlock(event, ctx);
4055 static unsigned int perf_poll(struct file *file, poll_table *wait)
4057 struct perf_event *event = file->private_data;
4058 struct ring_buffer *rb;
4059 unsigned int events = POLLHUP;
4061 poll_wait(file, &event->waitq, wait);
4063 if (is_event_hup(event))
4067 * Pin the event->rb by taking event->mmap_mutex; otherwise
4068 * perf_event_set_output() can swizzle our rb and make us miss wakeups.
4070 mutex_lock(&event->mmap_mutex);
4073 events = atomic_xchg(&rb->poll, 0);
4074 mutex_unlock(&event->mmap_mutex);
4078 static void _perf_event_reset(struct perf_event *event)
4080 (void)perf_event_read(event, false);
4081 local64_set(&event->count, 0);
4082 perf_event_update_userpage(event);
4086 * Holding the top-level event's child_mutex means that any
4087 * descendant process that has inherited this event will block
4088 * in perf_event_exit_event() if it goes to exit, thus satisfying the
4089 * task existence requirements of perf_event_enable/disable.
4091 static void perf_event_for_each_child(struct perf_event *event,
4092 void (*func)(struct perf_event *))
4094 struct perf_event *child;
4096 WARN_ON_ONCE(event->ctx->parent_ctx);
4098 mutex_lock(&event->child_mutex);
4100 list_for_each_entry(child, &event->child_list, child_list)
4102 mutex_unlock(&event->child_mutex);
4105 static void perf_event_for_each(struct perf_event *event,
4106 void (*func)(struct perf_event *))
4108 struct perf_event_context *ctx = event->ctx;
4109 struct perf_event *sibling;
4111 lockdep_assert_held(&ctx->mutex);
4113 event = event->group_leader;
4115 perf_event_for_each_child(event, func);
4116 list_for_each_entry(sibling, &event->sibling_list, group_entry)
4117 perf_event_for_each_child(sibling, func);
4120 static void __perf_event_period(struct perf_event *event,
4121 struct perf_cpu_context *cpuctx,
4122 struct perf_event_context *ctx,
4125 u64 value = *((u64 *)info);
4128 if (event->attr.freq) {
4129 event->attr.sample_freq = value;
4131 event->attr.sample_period = value;
4132 event->hw.sample_period = value;
4135 active = (event->state == PERF_EVENT_STATE_ACTIVE);
4137 perf_pmu_disable(ctx->pmu);
4138 event->pmu->stop(event, PERF_EF_UPDATE);
4141 local64_set(&event->hw.period_left, 0);
4144 event->pmu->start(event, PERF_EF_RELOAD);
4145 perf_pmu_enable(ctx->pmu);
4149 static int perf_event_period(struct perf_event *event, u64 __user *arg)
4153 if (!is_sampling_event(event))
4156 if (copy_from_user(&value, arg, sizeof(value)))
4162 if (event->attr.freq && value > sysctl_perf_event_sample_rate)
4165 event_function_call(event, __perf_event_period, &value);
4170 static const struct file_operations perf_fops;
4172 static inline int perf_fget_light(int fd, struct fd *p)
4174 struct fd f = fdget(fd);
4178 if (f.file->f_op != &perf_fops) {
4186 static int perf_event_set_output(struct perf_event *event,
4187 struct perf_event *output_event);
4188 static int perf_event_set_filter(struct perf_event *event, void __user *arg);
4189 static int perf_event_set_bpf_prog(struct perf_event *event, u32 prog_fd);
4191 static long _perf_ioctl(struct perf_event *event, unsigned int cmd, unsigned long arg)
4193 void (*func)(struct perf_event *);
4197 case PERF_EVENT_IOC_ENABLE:
4198 func = _perf_event_enable;
4200 case PERF_EVENT_IOC_DISABLE:
4201 func = _perf_event_disable;
4203 case PERF_EVENT_IOC_RESET:
4204 func = _perf_event_reset;
4207 case PERF_EVENT_IOC_REFRESH:
4208 return _perf_event_refresh(event, arg);
4210 case PERF_EVENT_IOC_PERIOD:
4211 return perf_event_period(event, (u64 __user *)arg);
4213 case PERF_EVENT_IOC_ID:
4215 u64 id = primary_event_id(event);
4217 if (copy_to_user((void __user *)arg, &id, sizeof(id)))
4222 case PERF_EVENT_IOC_SET_OUTPUT:
4226 struct perf_event *output_event;
4228 ret = perf_fget_light(arg, &output);
4231 output_event = output.file->private_data;
4232 ret = perf_event_set_output(event, output_event);
4235 ret = perf_event_set_output(event, NULL);
4240 case PERF_EVENT_IOC_SET_FILTER:
4241 return perf_event_set_filter(event, (void __user *)arg);
4243 case PERF_EVENT_IOC_SET_BPF:
4244 return perf_event_set_bpf_prog(event, arg);
4250 if (flags & PERF_IOC_FLAG_GROUP)
4251 perf_event_for_each(event, func);
4253 perf_event_for_each_child(event, func);
4258 static long perf_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
4260 struct perf_event *event = file->private_data;
4261 struct perf_event_context *ctx;
4264 ctx = perf_event_ctx_lock(event);
4265 ret = _perf_ioctl(event, cmd, arg);
4266 perf_event_ctx_unlock(event, ctx);
4271 #ifdef CONFIG_COMPAT
4272 static long perf_compat_ioctl(struct file *file, unsigned int cmd,
4275 switch (_IOC_NR(cmd)) {
4276 case _IOC_NR(PERF_EVENT_IOC_SET_FILTER):
4277 case _IOC_NR(PERF_EVENT_IOC_ID):
4278 /* Fix up pointer size (usually 4 -> 8 in 32-on-64-bit case */
4279 if (_IOC_SIZE(cmd) == sizeof(compat_uptr_t)) {
4280 cmd &= ~IOCSIZE_MASK;
4281 cmd |= sizeof(void *) << IOCSIZE_SHIFT;
4285 return perf_ioctl(file, cmd, arg);
4288 # define perf_compat_ioctl NULL
4291 int perf_event_task_enable(void)
4293 struct perf_event_context *ctx;
4294 struct perf_event *event;
4296 mutex_lock(¤t->perf_event_mutex);
4297 list_for_each_entry(event, ¤t->perf_event_list, owner_entry) {
4298 ctx = perf_event_ctx_lock(event);
4299 perf_event_for_each_child(event, _perf_event_enable);
4300 perf_event_ctx_unlock(event, ctx);
4302 mutex_unlock(¤t->perf_event_mutex);
4307 int perf_event_task_disable(void)
4309 struct perf_event_context *ctx;
4310 struct perf_event *event;
4312 mutex_lock(¤t->perf_event_mutex);
4313 list_for_each_entry(event, ¤t->perf_event_list, owner_entry) {
4314 ctx = perf_event_ctx_lock(event);
4315 perf_event_for_each_child(event, _perf_event_disable);
4316 perf_event_ctx_unlock(event, ctx);
4318 mutex_unlock(¤t->perf_event_mutex);
4323 static int perf_event_index(struct perf_event *event)
4325 if (event->hw.state & PERF_HES_STOPPED)
4328 if (event->state != PERF_EVENT_STATE_ACTIVE)
4331 return event->pmu->event_idx(event);
4334 static void calc_timer_values(struct perf_event *event,
4341 *now = perf_clock();
4342 ctx_time = event->shadow_ctx_time + *now;
4343 *enabled = ctx_time - event->tstamp_enabled;
4344 *running = ctx_time - event->tstamp_running;
4347 static void perf_event_init_userpage(struct perf_event *event)
4349 struct perf_event_mmap_page *userpg;
4350 struct ring_buffer *rb;
4353 rb = rcu_dereference(event->rb);
4357 userpg = rb->user_page;
4359 /* Allow new userspace to detect that bit 0 is deprecated */
4360 userpg->cap_bit0_is_deprecated = 1;
4361 userpg->size = offsetof(struct perf_event_mmap_page, __reserved);
4362 userpg->data_offset = PAGE_SIZE;
4363 userpg->data_size = perf_data_size(rb);
4369 void __weak arch_perf_update_userpage(
4370 struct perf_event *event, struct perf_event_mmap_page *userpg, u64 now)
4375 * Callers need to ensure there can be no nesting of this function, otherwise
4376 * the seqlock logic goes bad. We can not serialize this because the arch
4377 * code calls this from NMI context.
4379 void perf_event_update_userpage(struct perf_event *event)
4381 struct perf_event_mmap_page *userpg;
4382 struct ring_buffer *rb;
4383 u64 enabled, running, now;
4386 rb = rcu_dereference(event->rb);
4391 * compute total_time_enabled, total_time_running
4392 * based on snapshot values taken when the event
4393 * was last scheduled in.
4395 * we cannot simply called update_context_time()
4396 * because of locking issue as we can be called in
4399 calc_timer_values(event, &now, &enabled, &running);
4401 userpg = rb->user_page;
4403 * Disable preemption so as to not let the corresponding user-space
4404 * spin too long if we get preempted.
4409 userpg->index = perf_event_index(event);
4410 userpg->offset = perf_event_count(event);
4412 userpg->offset -= local64_read(&event->hw.prev_count);
4414 userpg->time_enabled = enabled +
4415 atomic64_read(&event->child_total_time_enabled);
4417 userpg->time_running = running +
4418 atomic64_read(&event->child_total_time_running);
4420 arch_perf_update_userpage(event, userpg, now);
4429 static int perf_mmap_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
4431 struct perf_event *event = vma->vm_file->private_data;
4432 struct ring_buffer *rb;
4433 int ret = VM_FAULT_SIGBUS;
4435 if (vmf->flags & FAULT_FLAG_MKWRITE) {
4436 if (vmf->pgoff == 0)
4442 rb = rcu_dereference(event->rb);
4446 if (vmf->pgoff && (vmf->flags & FAULT_FLAG_WRITE))
4449 vmf->page = perf_mmap_to_page(rb, vmf->pgoff);
4453 get_page(vmf->page);
4454 vmf->page->mapping = vma->vm_file->f_mapping;
4455 vmf->page->index = vmf->pgoff;
4464 static void ring_buffer_attach(struct perf_event *event,
4465 struct ring_buffer *rb)
4467 struct ring_buffer *old_rb = NULL;
4468 unsigned long flags;
4472 * Should be impossible, we set this when removing
4473 * event->rb_entry and wait/clear when adding event->rb_entry.
4475 WARN_ON_ONCE(event->rcu_pending);
4478 spin_lock_irqsave(&old_rb->event_lock, flags);
4479 list_del_rcu(&event->rb_entry);
4480 spin_unlock_irqrestore(&old_rb->event_lock, flags);
4482 event->rcu_batches = get_state_synchronize_rcu();
4483 event->rcu_pending = 1;
4487 if (event->rcu_pending) {
4488 cond_synchronize_rcu(event->rcu_batches);
4489 event->rcu_pending = 0;
4492 spin_lock_irqsave(&rb->event_lock, flags);
4493 list_add_rcu(&event->rb_entry, &rb->event_list);
4494 spin_unlock_irqrestore(&rb->event_lock, flags);
4497 rcu_assign_pointer(event->rb, rb);
4500 ring_buffer_put(old_rb);
4502 * Since we detached before setting the new rb, so that we
4503 * could attach the new rb, we could have missed a wakeup.
4506 wake_up_all(&event->waitq);
4510 static void ring_buffer_wakeup(struct perf_event *event)
4512 struct ring_buffer *rb;
4515 rb = rcu_dereference(event->rb);
4517 list_for_each_entry_rcu(event, &rb->event_list, rb_entry)
4518 wake_up_all(&event->waitq);
4523 struct ring_buffer *ring_buffer_get(struct perf_event *event)
4525 struct ring_buffer *rb;
4528 rb = rcu_dereference(event->rb);
4530 if (!atomic_inc_not_zero(&rb->refcount))
4538 void ring_buffer_put(struct ring_buffer *rb)
4540 if (!atomic_dec_and_test(&rb->refcount))
4543 WARN_ON_ONCE(!list_empty(&rb->event_list));
4545 call_rcu(&rb->rcu_head, rb_free_rcu);
4548 static void perf_mmap_open(struct vm_area_struct *vma)
4550 struct perf_event *event = vma->vm_file->private_data;
4552 atomic_inc(&event->mmap_count);
4553 atomic_inc(&event->rb->mmap_count);
4556 atomic_inc(&event->rb->aux_mmap_count);
4558 if (event->pmu->event_mapped)
4559 event->pmu->event_mapped(event);
4563 * A buffer can be mmap()ed multiple times; either directly through the same
4564 * event, or through other events by use of perf_event_set_output().
4566 * In order to undo the VM accounting done by perf_mmap() we need to destroy
4567 * the buffer here, where we still have a VM context. This means we need
4568 * to detach all events redirecting to us.
4570 static void perf_mmap_close(struct vm_area_struct *vma)
4572 struct perf_event *event = vma->vm_file->private_data;
4574 struct ring_buffer *rb = ring_buffer_get(event);
4575 struct user_struct *mmap_user = rb->mmap_user;
4576 int mmap_locked = rb->mmap_locked;
4577 unsigned long size = perf_data_size(rb);
4579 if (event->pmu->event_unmapped)
4580 event->pmu->event_unmapped(event);
4583 * rb->aux_mmap_count will always drop before rb->mmap_count and
4584 * event->mmap_count, so it is ok to use event->mmap_mutex to
4585 * serialize with perf_mmap here.
4587 if (rb_has_aux(rb) && vma->vm_pgoff == rb->aux_pgoff &&
4588 atomic_dec_and_mutex_lock(&rb->aux_mmap_count, &event->mmap_mutex)) {
4589 atomic_long_sub(rb->aux_nr_pages, &mmap_user->locked_vm);
4590 vma->vm_mm->pinned_vm -= rb->aux_mmap_locked;
4593 mutex_unlock(&event->mmap_mutex);
4596 atomic_dec(&rb->mmap_count);
4598 if (!atomic_dec_and_mutex_lock(&event->mmap_count, &event->mmap_mutex))
4601 ring_buffer_attach(event, NULL);
4602 mutex_unlock(&event->mmap_mutex);
4604 /* If there's still other mmap()s of this buffer, we're done. */
4605 if (atomic_read(&rb->mmap_count))
4609 * No other mmap()s, detach from all other events that might redirect
4610 * into the now unreachable buffer. Somewhat complicated by the
4611 * fact that rb::event_lock otherwise nests inside mmap_mutex.
4615 list_for_each_entry_rcu(event, &rb->event_list, rb_entry) {
4616 if (!atomic_long_inc_not_zero(&event->refcount)) {
4618 * This event is en-route to free_event() which will
4619 * detach it and remove it from the list.
4625 mutex_lock(&event->mmap_mutex);
4627 * Check we didn't race with perf_event_set_output() which can
4628 * swizzle the rb from under us while we were waiting to
4629 * acquire mmap_mutex.
4631 * If we find a different rb; ignore this event, a next
4632 * iteration will no longer find it on the list. We have to
4633 * still restart the iteration to make sure we're not now
4634 * iterating the wrong list.
4636 if (event->rb == rb)
4637 ring_buffer_attach(event, NULL);
4639 mutex_unlock(&event->mmap_mutex);
4643 * Restart the iteration; either we're on the wrong list or
4644 * destroyed its integrity by doing a deletion.
4651 * It could be there's still a few 0-ref events on the list; they'll
4652 * get cleaned up by free_event() -- they'll also still have their
4653 * ref on the rb and will free it whenever they are done with it.
4655 * Aside from that, this buffer is 'fully' detached and unmapped,
4656 * undo the VM accounting.
4659 atomic_long_sub((size >> PAGE_SHIFT) + 1, &mmap_user->locked_vm);
4660 vma->vm_mm->pinned_vm -= mmap_locked;
4661 free_uid(mmap_user);
4664 ring_buffer_put(rb); /* could be last */
4667 static const struct vm_operations_struct perf_mmap_vmops = {
4668 .open = perf_mmap_open,
4669 .close = perf_mmap_close, /* non mergable */
4670 .fault = perf_mmap_fault,
4671 .page_mkwrite = perf_mmap_fault,
4674 static int perf_mmap(struct file *file, struct vm_area_struct *vma)
4676 struct perf_event *event = file->private_data;
4677 unsigned long user_locked, user_lock_limit;
4678 struct user_struct *user = current_user();
4679 unsigned long locked, lock_limit;
4680 struct ring_buffer *rb = NULL;
4681 unsigned long vma_size;
4682 unsigned long nr_pages;
4683 long user_extra = 0, extra = 0;
4684 int ret = 0, flags = 0;
4687 * Don't allow mmap() of inherited per-task counters. This would
4688 * create a performance issue due to all children writing to the
4691 if (event->cpu == -1 && event->attr.inherit)
4694 if (!(vma->vm_flags & VM_SHARED))
4697 vma_size = vma->vm_end - vma->vm_start;
4699 if (vma->vm_pgoff == 0) {
4700 nr_pages = (vma_size / PAGE_SIZE) - 1;
4703 * AUX area mapping: if rb->aux_nr_pages != 0, it's already
4704 * mapped, all subsequent mappings should have the same size
4705 * and offset. Must be above the normal perf buffer.
4707 u64 aux_offset, aux_size;
4712 nr_pages = vma_size / PAGE_SIZE;
4714 mutex_lock(&event->mmap_mutex);
4721 aux_offset = ACCESS_ONCE(rb->user_page->aux_offset);
4722 aux_size = ACCESS_ONCE(rb->user_page->aux_size);
4724 if (aux_offset < perf_data_size(rb) + PAGE_SIZE)
4727 if (aux_offset != vma->vm_pgoff << PAGE_SHIFT)
4730 /* already mapped with a different offset */
4731 if (rb_has_aux(rb) && rb->aux_pgoff != vma->vm_pgoff)
4734 if (aux_size != vma_size || aux_size != nr_pages * PAGE_SIZE)
4737 /* already mapped with a different size */
4738 if (rb_has_aux(rb) && rb->aux_nr_pages != nr_pages)
4741 if (!is_power_of_2(nr_pages))
4744 if (!atomic_inc_not_zero(&rb->mmap_count))
4747 if (rb_has_aux(rb)) {
4748 atomic_inc(&rb->aux_mmap_count);
4753 atomic_set(&rb->aux_mmap_count, 1);
4754 user_extra = nr_pages;
4760 * If we have rb pages ensure they're a power-of-two number, so we
4761 * can do bitmasks instead of modulo.
4763 if (nr_pages != 0 && !is_power_of_2(nr_pages))
4766 if (vma_size != PAGE_SIZE * (1 + nr_pages))
4769 WARN_ON_ONCE(event->ctx->parent_ctx);
4771 mutex_lock(&event->mmap_mutex);
4773 if (event->rb->nr_pages != nr_pages) {
4778 if (!atomic_inc_not_zero(&event->rb->mmap_count)) {
4780 * Raced against perf_mmap_close() through
4781 * perf_event_set_output(). Try again, hope for better
4784 mutex_unlock(&event->mmap_mutex);
4791 user_extra = nr_pages + 1;
4794 user_lock_limit = sysctl_perf_event_mlock >> (PAGE_SHIFT - 10);
4797 * Increase the limit linearly with more CPUs:
4799 user_lock_limit *= num_online_cpus();
4801 user_locked = atomic_long_read(&user->locked_vm) + user_extra;
4803 if (user_locked > user_lock_limit)
4804 extra = user_locked - user_lock_limit;
4806 lock_limit = rlimit(RLIMIT_MEMLOCK);
4807 lock_limit >>= PAGE_SHIFT;
4808 locked = vma->vm_mm->pinned_vm + extra;
4810 if ((locked > lock_limit) && perf_paranoid_tracepoint_raw() &&
4811 !capable(CAP_IPC_LOCK)) {
4816 WARN_ON(!rb && event->rb);
4818 if (vma->vm_flags & VM_WRITE)
4819 flags |= RING_BUFFER_WRITABLE;
4822 rb = rb_alloc(nr_pages,
4823 event->attr.watermark ? event->attr.wakeup_watermark : 0,
4831 atomic_set(&rb->mmap_count, 1);
4832 rb->mmap_user = get_current_user();
4833 rb->mmap_locked = extra;
4835 ring_buffer_attach(event, rb);
4837 perf_event_init_userpage(event);
4838 perf_event_update_userpage(event);
4840 ret = rb_alloc_aux(rb, event, vma->vm_pgoff, nr_pages,
4841 event->attr.aux_watermark, flags);
4843 rb->aux_mmap_locked = extra;
4848 atomic_long_add(user_extra, &user->locked_vm);
4849 vma->vm_mm->pinned_vm += extra;
4851 atomic_inc(&event->mmap_count);
4853 atomic_dec(&rb->mmap_count);
4856 mutex_unlock(&event->mmap_mutex);
4859 * Since pinned accounting is per vm we cannot allow fork() to copy our
4862 vma->vm_flags |= VM_DONTCOPY | VM_DONTEXPAND | VM_DONTDUMP;
4863 vma->vm_ops = &perf_mmap_vmops;
4865 if (event->pmu->event_mapped)
4866 event->pmu->event_mapped(event);
4871 static int perf_fasync(int fd, struct file *filp, int on)
4873 struct inode *inode = file_inode(filp);
4874 struct perf_event *event = filp->private_data;
4878 retval = fasync_helper(fd, filp, on, &event->fasync);
4879 inode_unlock(inode);
4887 static const struct file_operations perf_fops = {
4888 .llseek = no_llseek,
4889 .release = perf_release,
4892 .unlocked_ioctl = perf_ioctl,
4893 .compat_ioctl = perf_compat_ioctl,
4895 .fasync = perf_fasync,
4901 * If there's data, ensure we set the poll() state and publish everything
4902 * to user-space before waking everybody up.
4905 static inline struct fasync_struct **perf_event_fasync(struct perf_event *event)
4907 /* only the parent has fasync state */
4909 event = event->parent;
4910 return &event->fasync;
4913 void perf_event_wakeup(struct perf_event *event)
4915 ring_buffer_wakeup(event);
4917 if (event->pending_kill) {
4918 kill_fasync(perf_event_fasync(event), SIGIO, event->pending_kill);
4919 event->pending_kill = 0;
4923 static void perf_pending_event(struct irq_work *entry)
4925 struct perf_event *event = container_of(entry,
4926 struct perf_event, pending);
4929 rctx = perf_swevent_get_recursion_context();
4931 * If we 'fail' here, that's OK, it means recursion is already disabled
4932 * and we won't recurse 'further'.
4935 if (event->pending_disable) {
4936 event->pending_disable = 0;
4937 perf_event_disable_local(event);
4940 if (event->pending_wakeup) {
4941 event->pending_wakeup = 0;
4942 perf_event_wakeup(event);
4946 perf_swevent_put_recursion_context(rctx);
4950 * We assume there is only KVM supporting the callbacks.
4951 * Later on, we might change it to a list if there is
4952 * another virtualization implementation supporting the callbacks.
4954 struct perf_guest_info_callbacks *perf_guest_cbs;
4956 int perf_register_guest_info_callbacks(struct perf_guest_info_callbacks *cbs)
4958 perf_guest_cbs = cbs;
4961 EXPORT_SYMBOL_GPL(perf_register_guest_info_callbacks);
4963 int perf_unregister_guest_info_callbacks(struct perf_guest_info_callbacks *cbs)
4965 perf_guest_cbs = NULL;
4968 EXPORT_SYMBOL_GPL(perf_unregister_guest_info_callbacks);
4971 perf_output_sample_regs(struct perf_output_handle *handle,
4972 struct pt_regs *regs, u64 mask)
4976 for_each_set_bit(bit, (const unsigned long *) &mask,
4977 sizeof(mask) * BITS_PER_BYTE) {
4980 val = perf_reg_value(regs, bit);
4981 perf_output_put(handle, val);
4985 static void perf_sample_regs_user(struct perf_regs *regs_user,
4986 struct pt_regs *regs,
4987 struct pt_regs *regs_user_copy)
4989 if (user_mode(regs)) {
4990 regs_user->abi = perf_reg_abi(current);
4991 regs_user->regs = regs;
4992 } else if (current->mm) {
4993 perf_get_regs_user(regs_user, regs, regs_user_copy);
4995 regs_user->abi = PERF_SAMPLE_REGS_ABI_NONE;
4996 regs_user->regs = NULL;
5000 static void perf_sample_regs_intr(struct perf_regs *regs_intr,
5001 struct pt_regs *regs)
5003 regs_intr->regs = regs;
5004 regs_intr->abi = perf_reg_abi(current);
5009 * Get remaining task size from user stack pointer.
5011 * It'd be better to take stack vma map and limit this more
5012 * precisly, but there's no way to get it safely under interrupt,
5013 * so using TASK_SIZE as limit.
5015 static u64 perf_ustack_task_size(struct pt_regs *regs)
5017 unsigned long addr = perf_user_stack_pointer(regs);
5019 if (!addr || addr >= TASK_SIZE)
5022 return TASK_SIZE - addr;
5026 perf_sample_ustack_size(u16 stack_size, u16 header_size,
5027 struct pt_regs *regs)
5031 /* No regs, no stack pointer, no dump. */
5036 * Check if we fit in with the requested stack size into the:
5038 * If we don't, we limit the size to the TASK_SIZE.
5040 * - remaining sample size
5041 * If we don't, we customize the stack size to
5042 * fit in to the remaining sample size.
5045 task_size = min((u64) USHRT_MAX, perf_ustack_task_size(regs));
5046 stack_size = min(stack_size, (u16) task_size);
5048 /* Current header size plus static size and dynamic size. */
5049 header_size += 2 * sizeof(u64);
5051 /* Do we fit in with the current stack dump size? */
5052 if ((u16) (header_size + stack_size) < header_size) {
5054 * If we overflow the maximum size for the sample,
5055 * we customize the stack dump size to fit in.
5057 stack_size = USHRT_MAX - header_size - sizeof(u64);
5058 stack_size = round_up(stack_size, sizeof(u64));
5065 perf_output_sample_ustack(struct perf_output_handle *handle, u64 dump_size,
5066 struct pt_regs *regs)
5068 /* Case of a kernel thread, nothing to dump */
5071 perf_output_put(handle, size);
5080 * - the size requested by user or the best one we can fit
5081 * in to the sample max size
5083 * - user stack dump data
5085 * - the actual dumped size
5089 perf_output_put(handle, dump_size);
5092 sp = perf_user_stack_pointer(regs);
5093 rem = __output_copy_user(handle, (void *) sp, dump_size);
5094 dyn_size = dump_size - rem;
5096 perf_output_skip(handle, rem);
5099 perf_output_put(handle, dyn_size);
5103 static void __perf_event_header__init_id(struct perf_event_header *header,
5104 struct perf_sample_data *data,
5105 struct perf_event *event)
5107 u64 sample_type = event->attr.sample_type;
5109 data->type = sample_type;
5110 header->size += event->id_header_size;
5112 if (sample_type & PERF_SAMPLE_TID) {
5113 /* namespace issues */
5114 data->tid_entry.pid = perf_event_pid(event, current);
5115 data->tid_entry.tid = perf_event_tid(event, current);
5118 if (sample_type & PERF_SAMPLE_TIME)
5119 data->time = perf_event_clock(event);
5121 if (sample_type & (PERF_SAMPLE_ID | PERF_SAMPLE_IDENTIFIER))
5122 data->id = primary_event_id(event);
5124 if (sample_type & PERF_SAMPLE_STREAM_ID)
5125 data->stream_id = event->id;
5127 if (sample_type & PERF_SAMPLE_CPU) {
5128 data->cpu_entry.cpu = raw_smp_processor_id();
5129 data->cpu_entry.reserved = 0;
5133 void perf_event_header__init_id(struct perf_event_header *header,
5134 struct perf_sample_data *data,
5135 struct perf_event *event)
5137 if (event->attr.sample_id_all)
5138 __perf_event_header__init_id(header, data, event);
5141 static void __perf_event__output_id_sample(struct perf_output_handle *handle,
5142 struct perf_sample_data *data)
5144 u64 sample_type = data->type;
5146 if (sample_type & PERF_SAMPLE_TID)
5147 perf_output_put(handle, data->tid_entry);
5149 if (sample_type & PERF_SAMPLE_TIME)
5150 perf_output_put(handle, data->time);
5152 if (sample_type & PERF_SAMPLE_ID)
5153 perf_output_put(handle, data->id);
5155 if (sample_type & PERF_SAMPLE_STREAM_ID)
5156 perf_output_put(handle, data->stream_id);
5158 if (sample_type & PERF_SAMPLE_CPU)
5159 perf_output_put(handle, data->cpu_entry);
5161 if (sample_type & PERF_SAMPLE_IDENTIFIER)
5162 perf_output_put(handle, data->id);
5165 void perf_event__output_id_sample(struct perf_event *event,
5166 struct perf_output_handle *handle,
5167 struct perf_sample_data *sample)
5169 if (event->attr.sample_id_all)
5170 __perf_event__output_id_sample(handle, sample);
5173 static void perf_output_read_one(struct perf_output_handle *handle,
5174 struct perf_event *event,
5175 u64 enabled, u64 running)
5177 u64 read_format = event->attr.read_format;
5181 values[n++] = perf_event_count(event);
5182 if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED) {
5183 values[n++] = enabled +
5184 atomic64_read(&event->child_total_time_enabled);
5186 if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING) {
5187 values[n++] = running +
5188 atomic64_read(&event->child_total_time_running);
5190 if (read_format & PERF_FORMAT_ID)
5191 values[n++] = primary_event_id(event);
5193 __output_copy(handle, values, n * sizeof(u64));
5197 * XXX PERF_FORMAT_GROUP vs inherited events seems difficult.
5199 static void perf_output_read_group(struct perf_output_handle *handle,
5200 struct perf_event *event,
5201 u64 enabled, u64 running)
5203 struct perf_event *leader = event->group_leader, *sub;
5204 u64 read_format = event->attr.read_format;
5208 values[n++] = 1 + leader->nr_siblings;
5210 if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED)
5211 values[n++] = enabled;
5213 if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING)
5214 values[n++] = running;
5216 if (leader != event)
5217 leader->pmu->read(leader);
5219 values[n++] = perf_event_count(leader);
5220 if (read_format & PERF_FORMAT_ID)
5221 values[n++] = primary_event_id(leader);
5223 __output_copy(handle, values, n * sizeof(u64));
5225 list_for_each_entry(sub, &leader->sibling_list, group_entry) {
5228 if ((sub != event) &&
5229 (sub->state == PERF_EVENT_STATE_ACTIVE))
5230 sub->pmu->read(sub);
5232 values[n++] = perf_event_count(sub);
5233 if (read_format & PERF_FORMAT_ID)
5234 values[n++] = primary_event_id(sub);
5236 __output_copy(handle, values, n * sizeof(u64));
5240 #define PERF_FORMAT_TOTAL_TIMES (PERF_FORMAT_TOTAL_TIME_ENABLED|\
5241 PERF_FORMAT_TOTAL_TIME_RUNNING)
5243 static void perf_output_read(struct perf_output_handle *handle,
5244 struct perf_event *event)
5246 u64 enabled = 0, running = 0, now;
5247 u64 read_format = event->attr.read_format;
5250 * compute total_time_enabled, total_time_running
5251 * based on snapshot values taken when the event
5252 * was last scheduled in.
5254 * we cannot simply called update_context_time()
5255 * because of locking issue as we are called in
5258 if (read_format & PERF_FORMAT_TOTAL_TIMES)
5259 calc_timer_values(event, &now, &enabled, &running);
5261 if (event->attr.read_format & PERF_FORMAT_GROUP)
5262 perf_output_read_group(handle, event, enabled, running);
5264 perf_output_read_one(handle, event, enabled, running);
5267 void perf_output_sample(struct perf_output_handle *handle,
5268 struct perf_event_header *header,
5269 struct perf_sample_data *data,
5270 struct perf_event *event)
5272 u64 sample_type = data->type;
5274 perf_output_put(handle, *header);
5276 if (sample_type & PERF_SAMPLE_IDENTIFIER)
5277 perf_output_put(handle, data->id);
5279 if (sample_type & PERF_SAMPLE_IP)
5280 perf_output_put(handle, data->ip);
5282 if (sample_type & PERF_SAMPLE_TID)
5283 perf_output_put(handle, data->tid_entry);
5285 if (sample_type & PERF_SAMPLE_TIME)
5286 perf_output_put(handle, data->time);
5288 if (sample_type & PERF_SAMPLE_ADDR)
5289 perf_output_put(handle, data->addr);
5291 if (sample_type & PERF_SAMPLE_ID)
5292 perf_output_put(handle, data->id);
5294 if (sample_type & PERF_SAMPLE_STREAM_ID)
5295 perf_output_put(handle, data->stream_id);
5297 if (sample_type & PERF_SAMPLE_CPU)
5298 perf_output_put(handle, data->cpu_entry);
5300 if (sample_type & PERF_SAMPLE_PERIOD)
5301 perf_output_put(handle, data->period);
5303 if (sample_type & PERF_SAMPLE_READ)
5304 perf_output_read(handle, event);
5306 if (sample_type & PERF_SAMPLE_CALLCHAIN) {
5307 if (data->callchain) {
5310 if (data->callchain)
5311 size += data->callchain->nr;
5313 size *= sizeof(u64);
5315 __output_copy(handle, data->callchain, size);
5318 perf_output_put(handle, nr);
5322 if (sample_type & PERF_SAMPLE_RAW) {
5324 u32 raw_size = data->raw->size;
5325 u32 real_size = round_up(raw_size + sizeof(u32),
5326 sizeof(u64)) - sizeof(u32);
5329 perf_output_put(handle, real_size);
5330 __output_copy(handle, data->raw->data, raw_size);
5331 if (real_size - raw_size)
5332 __output_copy(handle, &zero, real_size - raw_size);
5338 .size = sizeof(u32),
5341 perf_output_put(handle, raw);
5345 if (sample_type & PERF_SAMPLE_BRANCH_STACK) {
5346 if (data->br_stack) {
5349 size = data->br_stack->nr
5350 * sizeof(struct perf_branch_entry);
5352 perf_output_put(handle, data->br_stack->nr);
5353 perf_output_copy(handle, data->br_stack->entries, size);
5356 * we always store at least the value of nr
5359 perf_output_put(handle, nr);
5363 if (sample_type & PERF_SAMPLE_REGS_USER) {
5364 u64 abi = data->regs_user.abi;
5367 * If there are no regs to dump, notice it through
5368 * first u64 being zero (PERF_SAMPLE_REGS_ABI_NONE).
5370 perf_output_put(handle, abi);
5373 u64 mask = event->attr.sample_regs_user;
5374 perf_output_sample_regs(handle,
5375 data->regs_user.regs,
5380 if (sample_type & PERF_SAMPLE_STACK_USER) {
5381 perf_output_sample_ustack(handle,
5382 data->stack_user_size,
5383 data->regs_user.regs);
5386 if (sample_type & PERF_SAMPLE_WEIGHT)
5387 perf_output_put(handle, data->weight);
5389 if (sample_type & PERF_SAMPLE_DATA_SRC)
5390 perf_output_put(handle, data->data_src.val);
5392 if (sample_type & PERF_SAMPLE_TRANSACTION)
5393 perf_output_put(handle, data->txn);
5395 if (sample_type & PERF_SAMPLE_REGS_INTR) {
5396 u64 abi = data->regs_intr.abi;
5398 * If there are no regs to dump, notice it through
5399 * first u64 being zero (PERF_SAMPLE_REGS_ABI_NONE).
5401 perf_output_put(handle, abi);
5404 u64 mask = event->attr.sample_regs_intr;
5406 perf_output_sample_regs(handle,
5407 data->regs_intr.regs,
5412 if (!event->attr.watermark) {
5413 int wakeup_events = event->attr.wakeup_events;
5415 if (wakeup_events) {
5416 struct ring_buffer *rb = handle->rb;
5417 int events = local_inc_return(&rb->events);
5419 if (events >= wakeup_events) {
5420 local_sub(wakeup_events, &rb->events);
5421 local_inc(&rb->wakeup);
5427 void perf_prepare_sample(struct perf_event_header *header,
5428 struct perf_sample_data *data,
5429 struct perf_event *event,
5430 struct pt_regs *regs)
5432 u64 sample_type = event->attr.sample_type;
5434 header->type = PERF_RECORD_SAMPLE;
5435 header->size = sizeof(*header) + event->header_size;
5438 header->misc |= perf_misc_flags(regs);
5440 __perf_event_header__init_id(header, data, event);
5442 if (sample_type & PERF_SAMPLE_IP)
5443 data->ip = perf_instruction_pointer(regs);
5445 if (sample_type & PERF_SAMPLE_CALLCHAIN) {
5448 data->callchain = perf_callchain(event, regs);
5450 if (data->callchain)
5451 size += data->callchain->nr;
5453 header->size += size * sizeof(u64);
5456 if (sample_type & PERF_SAMPLE_RAW) {
5457 int size = sizeof(u32);
5460 size += data->raw->size;
5462 size += sizeof(u32);
5464 header->size += round_up(size, sizeof(u64));
5467 if (sample_type & PERF_SAMPLE_BRANCH_STACK) {
5468 int size = sizeof(u64); /* nr */
5469 if (data->br_stack) {
5470 size += data->br_stack->nr
5471 * sizeof(struct perf_branch_entry);
5473 header->size += size;
5476 if (sample_type & (PERF_SAMPLE_REGS_USER | PERF_SAMPLE_STACK_USER))
5477 perf_sample_regs_user(&data->regs_user, regs,
5478 &data->regs_user_copy);
5480 if (sample_type & PERF_SAMPLE_REGS_USER) {
5481 /* regs dump ABI info */
5482 int size = sizeof(u64);
5484 if (data->regs_user.regs) {
5485 u64 mask = event->attr.sample_regs_user;
5486 size += hweight64(mask) * sizeof(u64);
5489 header->size += size;
5492 if (sample_type & PERF_SAMPLE_STACK_USER) {
5494 * Either we need PERF_SAMPLE_STACK_USER bit to be allways
5495 * processed as the last one or have additional check added
5496 * in case new sample type is added, because we could eat
5497 * up the rest of the sample size.
5499 u16 stack_size = event->attr.sample_stack_user;
5500 u16 size = sizeof(u64);
5502 stack_size = perf_sample_ustack_size(stack_size, header->size,
5503 data->regs_user.regs);
5506 * If there is something to dump, add space for the dump
5507 * itself and for the field that tells the dynamic size,
5508 * which is how many have been actually dumped.
5511 size += sizeof(u64) + stack_size;
5513 data->stack_user_size = stack_size;
5514 header->size += size;
5517 if (sample_type & PERF_SAMPLE_REGS_INTR) {
5518 /* regs dump ABI info */
5519 int size = sizeof(u64);
5521 perf_sample_regs_intr(&data->regs_intr, regs);
5523 if (data->regs_intr.regs) {
5524 u64 mask = event->attr.sample_regs_intr;
5526 size += hweight64(mask) * sizeof(u64);
5529 header->size += size;
5533 void perf_event_output(struct perf_event *event,
5534 struct perf_sample_data *data,
5535 struct pt_regs *regs)
5537 struct perf_output_handle handle;
5538 struct perf_event_header header;
5540 /* protect the callchain buffers */
5543 perf_prepare_sample(&header, data, event, regs);
5545 if (perf_output_begin(&handle, event, header.size))
5548 perf_output_sample(&handle, &header, data, event);
5550 perf_output_end(&handle);
5560 struct perf_read_event {
5561 struct perf_event_header header;
5568 perf_event_read_event(struct perf_event *event,
5569 struct task_struct *task)
5571 struct perf_output_handle handle;
5572 struct perf_sample_data sample;
5573 struct perf_read_event read_event = {
5575 .type = PERF_RECORD_READ,
5577 .size = sizeof(read_event) + event->read_size,
5579 .pid = perf_event_pid(event, task),
5580 .tid = perf_event_tid(event, task),
5584 perf_event_header__init_id(&read_event.header, &sample, event);
5585 ret = perf_output_begin(&handle, event, read_event.header.size);
5589 perf_output_put(&handle, read_event);
5590 perf_output_read(&handle, event);
5591 perf_event__output_id_sample(event, &handle, &sample);
5593 perf_output_end(&handle);
5596 typedef void (perf_event_aux_output_cb)(struct perf_event *event, void *data);
5599 perf_event_aux_ctx(struct perf_event_context *ctx,
5600 perf_event_aux_output_cb output,
5603 struct perf_event *event;
5605 list_for_each_entry_rcu(event, &ctx->event_list, event_entry) {
5606 if (event->state < PERF_EVENT_STATE_INACTIVE)
5608 if (!event_filter_match(event))
5610 output(event, data);
5615 perf_event_aux_task_ctx(perf_event_aux_output_cb output, void *data,
5616 struct perf_event_context *task_ctx)
5620 perf_event_aux_ctx(task_ctx, output, data);
5626 perf_event_aux(perf_event_aux_output_cb output, void *data,
5627 struct perf_event_context *task_ctx)
5629 struct perf_cpu_context *cpuctx;
5630 struct perf_event_context *ctx;
5635 * If we have task_ctx != NULL we only notify
5636 * the task context itself. The task_ctx is set
5637 * only for EXIT events before releasing task
5641 perf_event_aux_task_ctx(output, data, task_ctx);
5646 list_for_each_entry_rcu(pmu, &pmus, entry) {
5647 cpuctx = get_cpu_ptr(pmu->pmu_cpu_context);
5648 if (cpuctx->unique_pmu != pmu)
5650 perf_event_aux_ctx(&cpuctx->ctx, output, data);
5651 ctxn = pmu->task_ctx_nr;
5654 ctx = rcu_dereference(current->perf_event_ctxp[ctxn]);
5656 perf_event_aux_ctx(ctx, output, data);
5658 put_cpu_ptr(pmu->pmu_cpu_context);
5664 * task tracking -- fork/exit
5666 * enabled by: attr.comm | attr.mmap | attr.mmap2 | attr.mmap_data | attr.task
5669 struct perf_task_event {
5670 struct task_struct *task;
5671 struct perf_event_context *task_ctx;
5674 struct perf_event_header header;
5684 static int perf_event_task_match(struct perf_event *event)
5686 return event->attr.comm || event->attr.mmap ||
5687 event->attr.mmap2 || event->attr.mmap_data ||
5691 static void perf_event_task_output(struct perf_event *event,
5694 struct perf_task_event *task_event = data;
5695 struct perf_output_handle handle;
5696 struct perf_sample_data sample;
5697 struct task_struct *task = task_event->task;
5698 int ret, size = task_event->event_id.header.size;
5700 if (!perf_event_task_match(event))
5703 perf_event_header__init_id(&task_event->event_id.header, &sample, event);
5705 ret = perf_output_begin(&handle, event,
5706 task_event->event_id.header.size);
5710 task_event->event_id.pid = perf_event_pid(event, task);
5711 task_event->event_id.ppid = perf_event_pid(event, current);
5713 task_event->event_id.tid = perf_event_tid(event, task);
5714 task_event->event_id.ptid = perf_event_tid(event, current);
5716 task_event->event_id.time = perf_event_clock(event);
5718 perf_output_put(&handle, task_event->event_id);
5720 perf_event__output_id_sample(event, &handle, &sample);
5722 perf_output_end(&handle);
5724 task_event->event_id.header.size = size;
5727 static void perf_event_task(struct task_struct *task,
5728 struct perf_event_context *task_ctx,
5731 struct perf_task_event task_event;
5733 if (!atomic_read(&nr_comm_events) &&
5734 !atomic_read(&nr_mmap_events) &&
5735 !atomic_read(&nr_task_events))
5738 task_event = (struct perf_task_event){
5740 .task_ctx = task_ctx,
5743 .type = new ? PERF_RECORD_FORK : PERF_RECORD_EXIT,
5745 .size = sizeof(task_event.event_id),
5755 perf_event_aux(perf_event_task_output,
5760 void perf_event_fork(struct task_struct *task)
5762 perf_event_task(task, NULL, 1);
5769 struct perf_comm_event {
5770 struct task_struct *task;
5775 struct perf_event_header header;
5782 static int perf_event_comm_match(struct perf_event *event)
5784 return event->attr.comm;
5787 static void perf_event_comm_output(struct perf_event *event,
5790 struct perf_comm_event *comm_event = data;
5791 struct perf_output_handle handle;
5792 struct perf_sample_data sample;
5793 int size = comm_event->event_id.header.size;
5796 if (!perf_event_comm_match(event))
5799 perf_event_header__init_id(&comm_event->event_id.header, &sample, event);
5800 ret = perf_output_begin(&handle, event,
5801 comm_event->event_id.header.size);
5806 comm_event->event_id.pid = perf_event_pid(event, comm_event->task);
5807 comm_event->event_id.tid = perf_event_tid(event, comm_event->task);
5809 perf_output_put(&handle, comm_event->event_id);
5810 __output_copy(&handle, comm_event->comm,
5811 comm_event->comm_size);
5813 perf_event__output_id_sample(event, &handle, &sample);
5815 perf_output_end(&handle);
5817 comm_event->event_id.header.size = size;
5820 static void perf_event_comm_event(struct perf_comm_event *comm_event)
5822 char comm[TASK_COMM_LEN];
5825 memset(comm, 0, sizeof(comm));
5826 strlcpy(comm, comm_event->task->comm, sizeof(comm));
5827 size = ALIGN(strlen(comm)+1, sizeof(u64));
5829 comm_event->comm = comm;
5830 comm_event->comm_size = size;
5832 comm_event->event_id.header.size = sizeof(comm_event->event_id) + size;
5834 perf_event_aux(perf_event_comm_output,
5839 void perf_event_comm(struct task_struct *task, bool exec)
5841 struct perf_comm_event comm_event;
5843 if (!atomic_read(&nr_comm_events))
5846 comm_event = (struct perf_comm_event){
5852 .type = PERF_RECORD_COMM,
5853 .misc = exec ? PERF_RECORD_MISC_COMM_EXEC : 0,
5861 perf_event_comm_event(&comm_event);
5868 struct perf_mmap_event {
5869 struct vm_area_struct *vma;
5871 const char *file_name;
5879 struct perf_event_header header;
5889 static int perf_event_mmap_match(struct perf_event *event,
5892 struct perf_mmap_event *mmap_event = data;
5893 struct vm_area_struct *vma = mmap_event->vma;
5894 int executable = vma->vm_flags & VM_EXEC;
5896 return (!executable && event->attr.mmap_data) ||
5897 (executable && (event->attr.mmap || event->attr.mmap2));
5900 static void perf_event_mmap_output(struct perf_event *event,
5903 struct perf_mmap_event *mmap_event = data;
5904 struct perf_output_handle handle;
5905 struct perf_sample_data sample;
5906 int size = mmap_event->event_id.header.size;
5909 if (!perf_event_mmap_match(event, data))
5912 if (event->attr.mmap2) {
5913 mmap_event->event_id.header.type = PERF_RECORD_MMAP2;
5914 mmap_event->event_id.header.size += sizeof(mmap_event->maj);
5915 mmap_event->event_id.header.size += sizeof(mmap_event->min);
5916 mmap_event->event_id.header.size += sizeof(mmap_event->ino);
5917 mmap_event->event_id.header.size += sizeof(mmap_event->ino_generation);
5918 mmap_event->event_id.header.size += sizeof(mmap_event->prot);
5919 mmap_event->event_id.header.size += sizeof(mmap_event->flags);
5922 perf_event_header__init_id(&mmap_event->event_id.header, &sample, event);
5923 ret = perf_output_begin(&handle, event,
5924 mmap_event->event_id.header.size);
5928 mmap_event->event_id.pid = perf_event_pid(event, current);
5929 mmap_event->event_id.tid = perf_event_tid(event, current);
5931 perf_output_put(&handle, mmap_event->event_id);
5933 if (event->attr.mmap2) {
5934 perf_output_put(&handle, mmap_event->maj);
5935 perf_output_put(&handle, mmap_event->min);
5936 perf_output_put(&handle, mmap_event->ino);
5937 perf_output_put(&handle, mmap_event->ino_generation);
5938 perf_output_put(&handle, mmap_event->prot);
5939 perf_output_put(&handle, mmap_event->flags);
5942 __output_copy(&handle, mmap_event->file_name,
5943 mmap_event->file_size);
5945 perf_event__output_id_sample(event, &handle, &sample);
5947 perf_output_end(&handle);
5949 mmap_event->event_id.header.size = size;
5952 static void perf_event_mmap_event(struct perf_mmap_event *mmap_event)
5954 struct vm_area_struct *vma = mmap_event->vma;
5955 struct file *file = vma->vm_file;
5956 int maj = 0, min = 0;
5957 u64 ino = 0, gen = 0;
5958 u32 prot = 0, flags = 0;
5965 struct inode *inode;
5968 buf = kmalloc(PATH_MAX, GFP_KERNEL);
5974 * d_path() works from the end of the rb backwards, so we
5975 * need to add enough zero bytes after the string to handle
5976 * the 64bit alignment we do later.
5978 name = file_path(file, buf, PATH_MAX - sizeof(u64));
5983 inode = file_inode(vma->vm_file);
5984 dev = inode->i_sb->s_dev;
5986 gen = inode->i_generation;
5990 if (vma->vm_flags & VM_READ)
5992 if (vma->vm_flags & VM_WRITE)
5994 if (vma->vm_flags & VM_EXEC)
5997 if (vma->vm_flags & VM_MAYSHARE)
6000 flags = MAP_PRIVATE;
6002 if (vma->vm_flags & VM_DENYWRITE)
6003 flags |= MAP_DENYWRITE;
6004 if (vma->vm_flags & VM_MAYEXEC)
6005 flags |= MAP_EXECUTABLE;
6006 if (vma->vm_flags & VM_LOCKED)
6007 flags |= MAP_LOCKED;
6008 if (vma->vm_flags & VM_HUGETLB)
6009 flags |= MAP_HUGETLB;
6013 if (vma->vm_ops && vma->vm_ops->name) {
6014 name = (char *) vma->vm_ops->name(vma);
6019 name = (char *)arch_vma_name(vma);
6023 if (vma->vm_start <= vma->vm_mm->start_brk &&
6024 vma->vm_end >= vma->vm_mm->brk) {
6028 if (vma->vm_start <= vma->vm_mm->start_stack &&
6029 vma->vm_end >= vma->vm_mm->start_stack) {
6039 strlcpy(tmp, name, sizeof(tmp));
6043 * Since our buffer works in 8 byte units we need to align our string
6044 * size to a multiple of 8. However, we must guarantee the tail end is
6045 * zero'd out to avoid leaking random bits to userspace.
6047 size = strlen(name)+1;
6048 while (!IS_ALIGNED(size, sizeof(u64)))
6049 name[size++] = '\0';
6051 mmap_event->file_name = name;
6052 mmap_event->file_size = size;
6053 mmap_event->maj = maj;
6054 mmap_event->min = min;
6055 mmap_event->ino = ino;
6056 mmap_event->ino_generation = gen;
6057 mmap_event->prot = prot;
6058 mmap_event->flags = flags;
6060 if (!(vma->vm_flags & VM_EXEC))
6061 mmap_event->event_id.header.misc |= PERF_RECORD_MISC_MMAP_DATA;
6063 mmap_event->event_id.header.size = sizeof(mmap_event->event_id) + size;
6065 perf_event_aux(perf_event_mmap_output,
6072 void perf_event_mmap(struct vm_area_struct *vma)
6074 struct perf_mmap_event mmap_event;
6076 if (!atomic_read(&nr_mmap_events))
6079 mmap_event = (struct perf_mmap_event){
6085 .type = PERF_RECORD_MMAP,
6086 .misc = PERF_RECORD_MISC_USER,
6091 .start = vma->vm_start,
6092 .len = vma->vm_end - vma->vm_start,
6093 .pgoff = (u64)vma->vm_pgoff << PAGE_SHIFT,
6095 /* .maj (attr_mmap2 only) */
6096 /* .min (attr_mmap2 only) */
6097 /* .ino (attr_mmap2 only) */
6098 /* .ino_generation (attr_mmap2 only) */
6099 /* .prot (attr_mmap2 only) */
6100 /* .flags (attr_mmap2 only) */
6103 perf_event_mmap_event(&mmap_event);
6106 void perf_event_aux_event(struct perf_event *event, unsigned long head,
6107 unsigned long size, u64 flags)
6109 struct perf_output_handle handle;
6110 struct perf_sample_data sample;
6111 struct perf_aux_event {
6112 struct perf_event_header header;
6118 .type = PERF_RECORD_AUX,
6120 .size = sizeof(rec),
6128 perf_event_header__init_id(&rec.header, &sample, event);
6129 ret = perf_output_begin(&handle, event, rec.header.size);
6134 perf_output_put(&handle, rec);
6135 perf_event__output_id_sample(event, &handle, &sample);
6137 perf_output_end(&handle);
6141 * Lost/dropped samples logging
6143 void perf_log_lost_samples(struct perf_event *event, u64 lost)
6145 struct perf_output_handle handle;
6146 struct perf_sample_data sample;
6150 struct perf_event_header header;
6152 } lost_samples_event = {
6154 .type = PERF_RECORD_LOST_SAMPLES,
6156 .size = sizeof(lost_samples_event),
6161 perf_event_header__init_id(&lost_samples_event.header, &sample, event);
6163 ret = perf_output_begin(&handle, event,
6164 lost_samples_event.header.size);
6168 perf_output_put(&handle, lost_samples_event);
6169 perf_event__output_id_sample(event, &handle, &sample);
6170 perf_output_end(&handle);
6174 * context_switch tracking
6177 struct perf_switch_event {
6178 struct task_struct *task;
6179 struct task_struct *next_prev;
6182 struct perf_event_header header;
6188 static int perf_event_switch_match(struct perf_event *event)
6190 return event->attr.context_switch;
6193 static void perf_event_switch_output(struct perf_event *event, void *data)
6195 struct perf_switch_event *se = data;
6196 struct perf_output_handle handle;
6197 struct perf_sample_data sample;
6200 if (!perf_event_switch_match(event))
6203 /* Only CPU-wide events are allowed to see next/prev pid/tid */
6204 if (event->ctx->task) {
6205 se->event_id.header.type = PERF_RECORD_SWITCH;
6206 se->event_id.header.size = sizeof(se->event_id.header);
6208 se->event_id.header.type = PERF_RECORD_SWITCH_CPU_WIDE;
6209 se->event_id.header.size = sizeof(se->event_id);
6210 se->event_id.next_prev_pid =
6211 perf_event_pid(event, se->next_prev);
6212 se->event_id.next_prev_tid =
6213 perf_event_tid(event, se->next_prev);
6216 perf_event_header__init_id(&se->event_id.header, &sample, event);
6218 ret = perf_output_begin(&handle, event, se->event_id.header.size);
6222 if (event->ctx->task)
6223 perf_output_put(&handle, se->event_id.header);
6225 perf_output_put(&handle, se->event_id);
6227 perf_event__output_id_sample(event, &handle, &sample);
6229 perf_output_end(&handle);
6232 static void perf_event_switch(struct task_struct *task,
6233 struct task_struct *next_prev, bool sched_in)
6235 struct perf_switch_event switch_event;
6237 /* N.B. caller checks nr_switch_events != 0 */
6239 switch_event = (struct perf_switch_event){
6241 .next_prev = next_prev,
6245 .misc = sched_in ? 0 : PERF_RECORD_MISC_SWITCH_OUT,
6248 /* .next_prev_pid */
6249 /* .next_prev_tid */
6253 perf_event_aux(perf_event_switch_output,
6259 * IRQ throttle logging
6262 static void perf_log_throttle(struct perf_event *event, int enable)
6264 struct perf_output_handle handle;
6265 struct perf_sample_data sample;
6269 struct perf_event_header header;
6273 } throttle_event = {
6275 .type = PERF_RECORD_THROTTLE,
6277 .size = sizeof(throttle_event),
6279 .time = perf_event_clock(event),
6280 .id = primary_event_id(event),
6281 .stream_id = event->id,
6285 throttle_event.header.type = PERF_RECORD_UNTHROTTLE;
6287 perf_event_header__init_id(&throttle_event.header, &sample, event);
6289 ret = perf_output_begin(&handle, event,
6290 throttle_event.header.size);
6294 perf_output_put(&handle, throttle_event);
6295 perf_event__output_id_sample(event, &handle, &sample);
6296 perf_output_end(&handle);
6299 static void perf_log_itrace_start(struct perf_event *event)
6301 struct perf_output_handle handle;
6302 struct perf_sample_data sample;
6303 struct perf_aux_event {
6304 struct perf_event_header header;
6311 event = event->parent;
6313 if (!(event->pmu->capabilities & PERF_PMU_CAP_ITRACE) ||
6314 event->hw.itrace_started)
6317 rec.header.type = PERF_RECORD_ITRACE_START;
6318 rec.header.misc = 0;
6319 rec.header.size = sizeof(rec);
6320 rec.pid = perf_event_pid(event, current);
6321 rec.tid = perf_event_tid(event, current);
6323 perf_event_header__init_id(&rec.header, &sample, event);
6324 ret = perf_output_begin(&handle, event, rec.header.size);
6329 perf_output_put(&handle, rec);
6330 perf_event__output_id_sample(event, &handle, &sample);
6332 perf_output_end(&handle);
6336 * Generic event overflow handling, sampling.
6339 static int __perf_event_overflow(struct perf_event *event,
6340 int throttle, struct perf_sample_data *data,
6341 struct pt_regs *regs)
6343 int events = atomic_read(&event->event_limit);
6344 struct hw_perf_event *hwc = &event->hw;
6349 * Non-sampling counters might still use the PMI to fold short
6350 * hardware counters, ignore those.
6352 if (unlikely(!is_sampling_event(event)))
6355 seq = __this_cpu_read(perf_throttled_seq);
6356 if (seq != hwc->interrupts_seq) {
6357 hwc->interrupts_seq = seq;
6358 hwc->interrupts = 1;
6361 if (unlikely(throttle
6362 && hwc->interrupts >= max_samples_per_tick)) {
6363 __this_cpu_inc(perf_throttled_count);
6364 hwc->interrupts = MAX_INTERRUPTS;
6365 perf_log_throttle(event, 0);
6366 tick_nohz_full_kick();
6371 if (event->attr.freq) {
6372 u64 now = perf_clock();
6373 s64 delta = now - hwc->freq_time_stamp;
6375 hwc->freq_time_stamp = now;
6377 if (delta > 0 && delta < 2*TICK_NSEC)
6378 perf_adjust_period(event, delta, hwc->last_period, true);
6382 * XXX event_limit might not quite work as expected on inherited
6386 event->pending_kill = POLL_IN;
6387 if (events && atomic_dec_and_test(&event->event_limit)) {
6389 event->pending_kill = POLL_HUP;
6390 event->pending_disable = 1;
6391 irq_work_queue(&event->pending);
6394 if (event->overflow_handler)
6395 event->overflow_handler(event, data, regs);
6397 perf_event_output(event, data, regs);
6399 if (*perf_event_fasync(event) && event->pending_kill) {
6400 event->pending_wakeup = 1;
6401 irq_work_queue(&event->pending);
6407 int perf_event_overflow(struct perf_event *event,
6408 struct perf_sample_data *data,
6409 struct pt_regs *regs)
6411 return __perf_event_overflow(event, 1, data, regs);
6415 * Generic software event infrastructure
6418 struct swevent_htable {
6419 struct swevent_hlist *swevent_hlist;
6420 struct mutex hlist_mutex;
6423 /* Recursion avoidance in each contexts */
6424 int recursion[PERF_NR_CONTEXTS];
6427 static DEFINE_PER_CPU(struct swevent_htable, swevent_htable);
6430 * We directly increment event->count and keep a second value in
6431 * event->hw.period_left to count intervals. This period event
6432 * is kept in the range [-sample_period, 0] so that we can use the
6436 u64 perf_swevent_set_period(struct perf_event *event)
6438 struct hw_perf_event *hwc = &event->hw;
6439 u64 period = hwc->last_period;
6443 hwc->last_period = hwc->sample_period;
6446 old = val = local64_read(&hwc->period_left);
6450 nr = div64_u64(period + val, period);
6451 offset = nr * period;
6453 if (local64_cmpxchg(&hwc->period_left, old, val) != old)
6459 static void perf_swevent_overflow(struct perf_event *event, u64 overflow,
6460 struct perf_sample_data *data,
6461 struct pt_regs *regs)
6463 struct hw_perf_event *hwc = &event->hw;
6467 overflow = perf_swevent_set_period(event);
6469 if (hwc->interrupts == MAX_INTERRUPTS)
6472 for (; overflow; overflow--) {
6473 if (__perf_event_overflow(event, throttle,
6476 * We inhibit the overflow from happening when
6477 * hwc->interrupts == MAX_INTERRUPTS.
6485 static void perf_swevent_event(struct perf_event *event, u64 nr,
6486 struct perf_sample_data *data,
6487 struct pt_regs *regs)
6489 struct hw_perf_event *hwc = &event->hw;
6491 local64_add(nr, &event->count);
6496 if (!is_sampling_event(event))
6499 if ((event->attr.sample_type & PERF_SAMPLE_PERIOD) && !event->attr.freq) {
6501 return perf_swevent_overflow(event, 1, data, regs);
6503 data->period = event->hw.last_period;
6505 if (nr == 1 && hwc->sample_period == 1 && !event->attr.freq)
6506 return perf_swevent_overflow(event, 1, data, regs);
6508 if (local64_add_negative(nr, &hwc->period_left))
6511 perf_swevent_overflow(event, 0, data, regs);
6514 static int perf_exclude_event(struct perf_event *event,
6515 struct pt_regs *regs)
6517 if (event->hw.state & PERF_HES_STOPPED)
6521 if (event->attr.exclude_user && user_mode(regs))
6524 if (event->attr.exclude_kernel && !user_mode(regs))
6531 static int perf_swevent_match(struct perf_event *event,
6532 enum perf_type_id type,
6534 struct perf_sample_data *data,
6535 struct pt_regs *regs)
6537 if (event->attr.type != type)
6540 if (event->attr.config != event_id)
6543 if (perf_exclude_event(event, regs))
6549 static inline u64 swevent_hash(u64 type, u32 event_id)
6551 u64 val = event_id | (type << 32);
6553 return hash_64(val, SWEVENT_HLIST_BITS);
6556 static inline struct hlist_head *
6557 __find_swevent_head(struct swevent_hlist *hlist, u64 type, u32 event_id)
6559 u64 hash = swevent_hash(type, event_id);
6561 return &hlist->heads[hash];
6564 /* For the read side: events when they trigger */
6565 static inline struct hlist_head *
6566 find_swevent_head_rcu(struct swevent_htable *swhash, u64 type, u32 event_id)
6568 struct swevent_hlist *hlist;
6570 hlist = rcu_dereference(swhash->swevent_hlist);
6574 return __find_swevent_head(hlist, type, event_id);
6577 /* For the event head insertion and removal in the hlist */
6578 static inline struct hlist_head *
6579 find_swevent_head(struct swevent_htable *swhash, struct perf_event *event)
6581 struct swevent_hlist *hlist;
6582 u32 event_id = event->attr.config;
6583 u64 type = event->attr.type;
6586 * Event scheduling is always serialized against hlist allocation
6587 * and release. Which makes the protected version suitable here.
6588 * The context lock guarantees that.
6590 hlist = rcu_dereference_protected(swhash->swevent_hlist,
6591 lockdep_is_held(&event->ctx->lock));
6595 return __find_swevent_head(hlist, type, event_id);
6598 static void do_perf_sw_event(enum perf_type_id type, u32 event_id,
6600 struct perf_sample_data *data,
6601 struct pt_regs *regs)
6603 struct swevent_htable *swhash = this_cpu_ptr(&swevent_htable);
6604 struct perf_event *event;
6605 struct hlist_head *head;
6608 head = find_swevent_head_rcu(swhash, type, event_id);
6612 hlist_for_each_entry_rcu(event, head, hlist_entry) {
6613 if (perf_swevent_match(event, type, event_id, data, regs))
6614 perf_swevent_event(event, nr, data, regs);
6620 DEFINE_PER_CPU(struct pt_regs, __perf_regs[4]);
6622 int perf_swevent_get_recursion_context(void)
6624 struct swevent_htable *swhash = this_cpu_ptr(&swevent_htable);
6626 return get_recursion_context(swhash->recursion);
6628 EXPORT_SYMBOL_GPL(perf_swevent_get_recursion_context);
6630 inline void perf_swevent_put_recursion_context(int rctx)
6632 struct swevent_htable *swhash = this_cpu_ptr(&swevent_htable);
6634 put_recursion_context(swhash->recursion, rctx);
6637 void ___perf_sw_event(u32 event_id, u64 nr, struct pt_regs *regs, u64 addr)
6639 struct perf_sample_data data;
6641 if (WARN_ON_ONCE(!regs))
6644 perf_sample_data_init(&data, addr, 0);
6645 do_perf_sw_event(PERF_TYPE_SOFTWARE, event_id, nr, &data, regs);
6648 void __perf_sw_event(u32 event_id, u64 nr, struct pt_regs *regs, u64 addr)
6652 preempt_disable_notrace();
6653 rctx = perf_swevent_get_recursion_context();
6654 if (unlikely(rctx < 0))
6657 ___perf_sw_event(event_id, nr, regs, addr);
6659 perf_swevent_put_recursion_context(rctx);
6661 preempt_enable_notrace();
6664 static void perf_swevent_read(struct perf_event *event)
6668 static int perf_swevent_add(struct perf_event *event, int flags)
6670 struct swevent_htable *swhash = this_cpu_ptr(&swevent_htable);
6671 struct hw_perf_event *hwc = &event->hw;
6672 struct hlist_head *head;
6674 if (is_sampling_event(event)) {
6675 hwc->last_period = hwc->sample_period;
6676 perf_swevent_set_period(event);
6679 hwc->state = !(flags & PERF_EF_START);
6681 head = find_swevent_head(swhash, event);
6682 if (WARN_ON_ONCE(!head))
6685 hlist_add_head_rcu(&event->hlist_entry, head);
6686 perf_event_update_userpage(event);
6691 static void perf_swevent_del(struct perf_event *event, int flags)
6693 hlist_del_rcu(&event->hlist_entry);
6696 static void perf_swevent_start(struct perf_event *event, int flags)
6698 event->hw.state = 0;
6701 static void perf_swevent_stop(struct perf_event *event, int flags)
6703 event->hw.state = PERF_HES_STOPPED;
6706 /* Deref the hlist from the update side */
6707 static inline struct swevent_hlist *
6708 swevent_hlist_deref(struct swevent_htable *swhash)
6710 return rcu_dereference_protected(swhash->swevent_hlist,
6711 lockdep_is_held(&swhash->hlist_mutex));
6714 static void swevent_hlist_release(struct swevent_htable *swhash)
6716 struct swevent_hlist *hlist = swevent_hlist_deref(swhash);
6721 RCU_INIT_POINTER(swhash->swevent_hlist, NULL);
6722 kfree_rcu(hlist, rcu_head);
6725 static void swevent_hlist_put_cpu(struct perf_event *event, int cpu)
6727 struct swevent_htable *swhash = &per_cpu(swevent_htable, cpu);
6729 mutex_lock(&swhash->hlist_mutex);
6731 if (!--swhash->hlist_refcount)
6732 swevent_hlist_release(swhash);
6734 mutex_unlock(&swhash->hlist_mutex);
6737 static void swevent_hlist_put(struct perf_event *event)
6741 for_each_possible_cpu(cpu)
6742 swevent_hlist_put_cpu(event, cpu);
6745 static int swevent_hlist_get_cpu(struct perf_event *event, int cpu)
6747 struct swevent_htable *swhash = &per_cpu(swevent_htable, cpu);
6750 mutex_lock(&swhash->hlist_mutex);
6751 if (!swevent_hlist_deref(swhash) && cpu_online(cpu)) {
6752 struct swevent_hlist *hlist;
6754 hlist = kzalloc(sizeof(*hlist), GFP_KERNEL);
6759 rcu_assign_pointer(swhash->swevent_hlist, hlist);
6761 swhash->hlist_refcount++;
6763 mutex_unlock(&swhash->hlist_mutex);
6768 static int swevent_hlist_get(struct perf_event *event)
6771 int cpu, failed_cpu;
6774 for_each_possible_cpu(cpu) {
6775 err = swevent_hlist_get_cpu(event, cpu);
6785 for_each_possible_cpu(cpu) {
6786 if (cpu == failed_cpu)
6788 swevent_hlist_put_cpu(event, cpu);
6795 struct static_key perf_swevent_enabled[PERF_COUNT_SW_MAX];
6797 static void sw_perf_event_destroy(struct perf_event *event)
6799 u64 event_id = event->attr.config;
6801 WARN_ON(event->parent);
6803 static_key_slow_dec(&perf_swevent_enabled[event_id]);
6804 swevent_hlist_put(event);
6807 static int perf_swevent_init(struct perf_event *event)
6809 u64 event_id = event->attr.config;
6811 if (event->attr.type != PERF_TYPE_SOFTWARE)
6815 * no branch sampling for software events
6817 if (has_branch_stack(event))
6821 case PERF_COUNT_SW_CPU_CLOCK:
6822 case PERF_COUNT_SW_TASK_CLOCK:
6829 if (event_id >= PERF_COUNT_SW_MAX)
6832 if (!event->parent) {
6835 err = swevent_hlist_get(event);
6839 static_key_slow_inc(&perf_swevent_enabled[event_id]);
6840 event->destroy = sw_perf_event_destroy;
6846 static struct pmu perf_swevent = {
6847 .task_ctx_nr = perf_sw_context,
6849 .capabilities = PERF_PMU_CAP_NO_NMI,
6851 .event_init = perf_swevent_init,
6852 .add = perf_swevent_add,
6853 .del = perf_swevent_del,
6854 .start = perf_swevent_start,
6855 .stop = perf_swevent_stop,
6856 .read = perf_swevent_read,
6859 #ifdef CONFIG_EVENT_TRACING
6861 static int perf_tp_filter_match(struct perf_event *event,
6862 struct perf_sample_data *data)
6864 void *record = data->raw->data;
6866 /* only top level events have filters set */
6868 event = event->parent;
6870 if (likely(!event->filter) || filter_match_preds(event->filter, record))
6875 static int perf_tp_event_match(struct perf_event *event,
6876 struct perf_sample_data *data,
6877 struct pt_regs *regs)
6879 if (event->hw.state & PERF_HES_STOPPED)
6882 * All tracepoints are from kernel-space.
6884 if (event->attr.exclude_kernel)
6887 if (!perf_tp_filter_match(event, data))
6893 void perf_tp_event(u64 addr, u64 count, void *record, int entry_size,
6894 struct pt_regs *regs, struct hlist_head *head, int rctx,
6895 struct task_struct *task)
6897 struct perf_sample_data data;
6898 struct perf_event *event;
6900 struct perf_raw_record raw = {
6905 perf_sample_data_init(&data, addr, 0);
6908 hlist_for_each_entry_rcu(event, head, hlist_entry) {
6909 if (perf_tp_event_match(event, &data, regs))
6910 perf_swevent_event(event, count, &data, regs);
6914 * If we got specified a target task, also iterate its context and
6915 * deliver this event there too.
6917 if (task && task != current) {
6918 struct perf_event_context *ctx;
6919 struct trace_entry *entry = record;
6922 ctx = rcu_dereference(task->perf_event_ctxp[perf_sw_context]);
6926 list_for_each_entry_rcu(event, &ctx->event_list, event_entry) {
6927 if (event->attr.type != PERF_TYPE_TRACEPOINT)
6929 if (event->attr.config != entry->type)
6931 if (perf_tp_event_match(event, &data, regs))
6932 perf_swevent_event(event, count, &data, regs);
6938 perf_swevent_put_recursion_context(rctx);
6940 EXPORT_SYMBOL_GPL(perf_tp_event);
6942 static void tp_perf_event_destroy(struct perf_event *event)
6944 perf_trace_destroy(event);
6947 static int perf_tp_event_init(struct perf_event *event)
6951 if (event->attr.type != PERF_TYPE_TRACEPOINT)
6955 * no branch sampling for tracepoint events
6957 if (has_branch_stack(event))
6960 err = perf_trace_init(event);
6964 event->destroy = tp_perf_event_destroy;
6969 static struct pmu perf_tracepoint = {
6970 .task_ctx_nr = perf_sw_context,
6972 .event_init = perf_tp_event_init,
6973 .add = perf_trace_add,
6974 .del = perf_trace_del,
6975 .start = perf_swevent_start,
6976 .stop = perf_swevent_stop,
6977 .read = perf_swevent_read,
6980 static inline void perf_tp_register(void)
6982 perf_pmu_register(&perf_tracepoint, "tracepoint", PERF_TYPE_TRACEPOINT);
6985 static int perf_event_set_filter(struct perf_event *event, void __user *arg)
6990 if (event->attr.type != PERF_TYPE_TRACEPOINT)
6993 filter_str = strndup_user(arg, PAGE_SIZE);
6994 if (IS_ERR(filter_str))
6995 return PTR_ERR(filter_str);
6997 ret = ftrace_profile_set_filter(event, event->attr.config, filter_str);
7003 static void perf_event_free_filter(struct perf_event *event)
7005 ftrace_profile_free_filter(event);
7008 static int perf_event_set_bpf_prog(struct perf_event *event, u32 prog_fd)
7010 struct bpf_prog *prog;
7012 if (event->attr.type != PERF_TYPE_TRACEPOINT)
7015 if (event->tp_event->prog)
7018 if (!(event->tp_event->flags & TRACE_EVENT_FL_UKPROBE))
7019 /* bpf programs can only be attached to u/kprobes */
7022 prog = bpf_prog_get(prog_fd);
7024 return PTR_ERR(prog);
7026 if (prog->type != BPF_PROG_TYPE_KPROBE) {
7027 /* valid fd, but invalid bpf program type */
7032 event->tp_event->prog = prog;
7037 static void perf_event_free_bpf_prog(struct perf_event *event)
7039 struct bpf_prog *prog;
7041 if (!event->tp_event)
7044 prog = event->tp_event->prog;
7046 event->tp_event->prog = NULL;
7053 static inline void perf_tp_register(void)
7057 static int perf_event_set_filter(struct perf_event *event, void __user *arg)
7062 static void perf_event_free_filter(struct perf_event *event)
7066 static int perf_event_set_bpf_prog(struct perf_event *event, u32 prog_fd)
7071 static void perf_event_free_bpf_prog(struct perf_event *event)
7074 #endif /* CONFIG_EVENT_TRACING */
7076 #ifdef CONFIG_HAVE_HW_BREAKPOINT
7077 void perf_bp_event(struct perf_event *bp, void *data)
7079 struct perf_sample_data sample;
7080 struct pt_regs *regs = data;
7082 perf_sample_data_init(&sample, bp->attr.bp_addr, 0);
7084 if (!bp->hw.state && !perf_exclude_event(bp, regs))
7085 perf_swevent_event(bp, 1, &sample, regs);
7090 * hrtimer based swevent callback
7093 static enum hrtimer_restart perf_swevent_hrtimer(struct hrtimer *hrtimer)
7095 enum hrtimer_restart ret = HRTIMER_RESTART;
7096 struct perf_sample_data data;
7097 struct pt_regs *regs;
7098 struct perf_event *event;
7101 event = container_of(hrtimer, struct perf_event, hw.hrtimer);
7103 if (event->state != PERF_EVENT_STATE_ACTIVE)
7104 return HRTIMER_NORESTART;
7106 event->pmu->read(event);
7108 perf_sample_data_init(&data, 0, event->hw.last_period);
7109 regs = get_irq_regs();
7111 if (regs && !perf_exclude_event(event, regs)) {
7112 if (!(event->attr.exclude_idle && is_idle_task(current)))
7113 if (__perf_event_overflow(event, 1, &data, regs))
7114 ret = HRTIMER_NORESTART;
7117 period = max_t(u64, 10000, event->hw.sample_period);
7118 hrtimer_forward_now(hrtimer, ns_to_ktime(period));
7123 static void perf_swevent_start_hrtimer(struct perf_event *event)
7125 struct hw_perf_event *hwc = &event->hw;
7128 if (!is_sampling_event(event))
7131 period = local64_read(&hwc->period_left);
7136 local64_set(&hwc->period_left, 0);
7138 period = max_t(u64, 10000, hwc->sample_period);
7140 hrtimer_start(&hwc->hrtimer, ns_to_ktime(period),
7141 HRTIMER_MODE_REL_PINNED);
7144 static void perf_swevent_cancel_hrtimer(struct perf_event *event)
7146 struct hw_perf_event *hwc = &event->hw;
7148 if (is_sampling_event(event)) {
7149 ktime_t remaining = hrtimer_get_remaining(&hwc->hrtimer);
7150 local64_set(&hwc->period_left, ktime_to_ns(remaining));
7152 hrtimer_cancel(&hwc->hrtimer);
7156 static void perf_swevent_init_hrtimer(struct perf_event *event)
7158 struct hw_perf_event *hwc = &event->hw;
7160 if (!is_sampling_event(event))
7163 hrtimer_init(&hwc->hrtimer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
7164 hwc->hrtimer.function = perf_swevent_hrtimer;
7167 * Since hrtimers have a fixed rate, we can do a static freq->period
7168 * mapping and avoid the whole period adjust feedback stuff.
7170 if (event->attr.freq) {
7171 long freq = event->attr.sample_freq;
7173 event->attr.sample_period = NSEC_PER_SEC / freq;
7174 hwc->sample_period = event->attr.sample_period;
7175 local64_set(&hwc->period_left, hwc->sample_period);
7176 hwc->last_period = hwc->sample_period;
7177 event->attr.freq = 0;
7182 * Software event: cpu wall time clock
7185 static void cpu_clock_event_update(struct perf_event *event)
7190 now = local_clock();
7191 prev = local64_xchg(&event->hw.prev_count, now);
7192 local64_add(now - prev, &event->count);
7195 static void cpu_clock_event_start(struct perf_event *event, int flags)
7197 local64_set(&event->hw.prev_count, local_clock());
7198 perf_swevent_start_hrtimer(event);
7201 static void cpu_clock_event_stop(struct perf_event *event, int flags)
7203 perf_swevent_cancel_hrtimer(event);
7204 cpu_clock_event_update(event);
7207 static int cpu_clock_event_add(struct perf_event *event, int flags)
7209 if (flags & PERF_EF_START)
7210 cpu_clock_event_start(event, flags);
7211 perf_event_update_userpage(event);
7216 static void cpu_clock_event_del(struct perf_event *event, int flags)
7218 cpu_clock_event_stop(event, flags);
7221 static void cpu_clock_event_read(struct perf_event *event)
7223 cpu_clock_event_update(event);
7226 static int cpu_clock_event_init(struct perf_event *event)
7228 if (event->attr.type != PERF_TYPE_SOFTWARE)
7231 if (event->attr.config != PERF_COUNT_SW_CPU_CLOCK)
7235 * no branch sampling for software events
7237 if (has_branch_stack(event))
7240 perf_swevent_init_hrtimer(event);
7245 static struct pmu perf_cpu_clock = {
7246 .task_ctx_nr = perf_sw_context,
7248 .capabilities = PERF_PMU_CAP_NO_NMI,
7250 .event_init = cpu_clock_event_init,
7251 .add = cpu_clock_event_add,
7252 .del = cpu_clock_event_del,
7253 .start = cpu_clock_event_start,
7254 .stop = cpu_clock_event_stop,
7255 .read = cpu_clock_event_read,
7259 * Software event: task time clock
7262 static void task_clock_event_update(struct perf_event *event, u64 now)
7267 prev = local64_xchg(&event->hw.prev_count, now);
7269 local64_add(delta, &event->count);
7272 static void task_clock_event_start(struct perf_event *event, int flags)
7274 local64_set(&event->hw.prev_count, event->ctx->time);
7275 perf_swevent_start_hrtimer(event);
7278 static void task_clock_event_stop(struct perf_event *event, int flags)
7280 perf_swevent_cancel_hrtimer(event);
7281 task_clock_event_update(event, event->ctx->time);
7284 static int task_clock_event_add(struct perf_event *event, int flags)
7286 if (flags & PERF_EF_START)
7287 task_clock_event_start(event, flags);
7288 perf_event_update_userpage(event);
7293 static void task_clock_event_del(struct perf_event *event, int flags)
7295 task_clock_event_stop(event, PERF_EF_UPDATE);
7298 static void task_clock_event_read(struct perf_event *event)
7300 u64 now = perf_clock();
7301 u64 delta = now - event->ctx->timestamp;
7302 u64 time = event->ctx->time + delta;
7304 task_clock_event_update(event, time);
7307 static int task_clock_event_init(struct perf_event *event)
7309 if (event->attr.type != PERF_TYPE_SOFTWARE)
7312 if (event->attr.config != PERF_COUNT_SW_TASK_CLOCK)
7316 * no branch sampling for software events
7318 if (has_branch_stack(event))
7321 perf_swevent_init_hrtimer(event);
7326 static struct pmu perf_task_clock = {
7327 .task_ctx_nr = perf_sw_context,
7329 .capabilities = PERF_PMU_CAP_NO_NMI,
7331 .event_init = task_clock_event_init,
7332 .add = task_clock_event_add,
7333 .del = task_clock_event_del,
7334 .start = task_clock_event_start,
7335 .stop = task_clock_event_stop,
7336 .read = task_clock_event_read,
7339 static void perf_pmu_nop_void(struct pmu *pmu)
7343 static void perf_pmu_nop_txn(struct pmu *pmu, unsigned int flags)
7347 static int perf_pmu_nop_int(struct pmu *pmu)
7352 static DEFINE_PER_CPU(unsigned int, nop_txn_flags);
7354 static void perf_pmu_start_txn(struct pmu *pmu, unsigned int flags)
7356 __this_cpu_write(nop_txn_flags, flags);
7358 if (flags & ~PERF_PMU_TXN_ADD)
7361 perf_pmu_disable(pmu);
7364 static int perf_pmu_commit_txn(struct pmu *pmu)
7366 unsigned int flags = __this_cpu_read(nop_txn_flags);
7368 __this_cpu_write(nop_txn_flags, 0);
7370 if (flags & ~PERF_PMU_TXN_ADD)
7373 perf_pmu_enable(pmu);
7377 static void perf_pmu_cancel_txn(struct pmu *pmu)
7379 unsigned int flags = __this_cpu_read(nop_txn_flags);
7381 __this_cpu_write(nop_txn_flags, 0);
7383 if (flags & ~PERF_PMU_TXN_ADD)
7386 perf_pmu_enable(pmu);
7389 static int perf_event_idx_default(struct perf_event *event)
7395 * Ensures all contexts with the same task_ctx_nr have the same
7396 * pmu_cpu_context too.
7398 static struct perf_cpu_context __percpu *find_pmu_context(int ctxn)
7405 list_for_each_entry(pmu, &pmus, entry) {
7406 if (pmu->task_ctx_nr == ctxn)
7407 return pmu->pmu_cpu_context;
7413 static void update_pmu_context(struct pmu *pmu, struct pmu *old_pmu)
7417 for_each_possible_cpu(cpu) {
7418 struct perf_cpu_context *cpuctx;
7420 cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
7422 if (cpuctx->unique_pmu == old_pmu)
7423 cpuctx->unique_pmu = pmu;
7427 static void free_pmu_context(struct pmu *pmu)
7431 mutex_lock(&pmus_lock);
7433 * Like a real lame refcount.
7435 list_for_each_entry(i, &pmus, entry) {
7436 if (i->pmu_cpu_context == pmu->pmu_cpu_context) {
7437 update_pmu_context(i, pmu);
7442 free_percpu(pmu->pmu_cpu_context);
7444 mutex_unlock(&pmus_lock);
7446 static struct idr pmu_idr;
7449 type_show(struct device *dev, struct device_attribute *attr, char *page)
7451 struct pmu *pmu = dev_get_drvdata(dev);
7453 return snprintf(page, PAGE_SIZE-1, "%d\n", pmu->type);
7455 static DEVICE_ATTR_RO(type);
7458 perf_event_mux_interval_ms_show(struct device *dev,
7459 struct device_attribute *attr,
7462 struct pmu *pmu = dev_get_drvdata(dev);
7464 return snprintf(page, PAGE_SIZE-1, "%d\n", pmu->hrtimer_interval_ms);
7467 static DEFINE_MUTEX(mux_interval_mutex);
7470 perf_event_mux_interval_ms_store(struct device *dev,
7471 struct device_attribute *attr,
7472 const char *buf, size_t count)
7474 struct pmu *pmu = dev_get_drvdata(dev);
7475 int timer, cpu, ret;
7477 ret = kstrtoint(buf, 0, &timer);
7484 /* same value, noting to do */
7485 if (timer == pmu->hrtimer_interval_ms)
7488 mutex_lock(&mux_interval_mutex);
7489 pmu->hrtimer_interval_ms = timer;
7491 /* update all cpuctx for this PMU */
7493 for_each_online_cpu(cpu) {
7494 struct perf_cpu_context *cpuctx;
7495 cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
7496 cpuctx->hrtimer_interval = ns_to_ktime(NSEC_PER_MSEC * timer);
7498 cpu_function_call(cpu,
7499 (remote_function_f)perf_mux_hrtimer_restart, cpuctx);
7502 mutex_unlock(&mux_interval_mutex);
7506 static DEVICE_ATTR_RW(perf_event_mux_interval_ms);
7508 static struct attribute *pmu_dev_attrs[] = {
7509 &dev_attr_type.attr,
7510 &dev_attr_perf_event_mux_interval_ms.attr,
7513 ATTRIBUTE_GROUPS(pmu_dev);
7515 static int pmu_bus_running;
7516 static struct bus_type pmu_bus = {
7517 .name = "event_source",
7518 .dev_groups = pmu_dev_groups,
7521 static void pmu_dev_release(struct device *dev)
7526 static int pmu_dev_alloc(struct pmu *pmu)
7530 pmu->dev = kzalloc(sizeof(struct device), GFP_KERNEL);
7534 pmu->dev->groups = pmu->attr_groups;
7535 device_initialize(pmu->dev);
7536 ret = dev_set_name(pmu->dev, "%s", pmu->name);
7540 dev_set_drvdata(pmu->dev, pmu);
7541 pmu->dev->bus = &pmu_bus;
7542 pmu->dev->release = pmu_dev_release;
7543 ret = device_add(pmu->dev);
7551 put_device(pmu->dev);
7555 static struct lock_class_key cpuctx_mutex;
7556 static struct lock_class_key cpuctx_lock;
7558 int perf_pmu_register(struct pmu *pmu, const char *name, int type)
7562 mutex_lock(&pmus_lock);
7564 pmu->pmu_disable_count = alloc_percpu(int);
7565 if (!pmu->pmu_disable_count)
7574 type = idr_alloc(&pmu_idr, pmu, PERF_TYPE_MAX, 0, GFP_KERNEL);
7582 if (pmu_bus_running) {
7583 ret = pmu_dev_alloc(pmu);
7589 pmu->pmu_cpu_context = find_pmu_context(pmu->task_ctx_nr);
7590 if (pmu->pmu_cpu_context)
7591 goto got_cpu_context;
7594 pmu->pmu_cpu_context = alloc_percpu(struct perf_cpu_context);
7595 if (!pmu->pmu_cpu_context)
7598 for_each_possible_cpu(cpu) {
7599 struct perf_cpu_context *cpuctx;
7601 cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
7602 __perf_event_init_context(&cpuctx->ctx);
7603 lockdep_set_class(&cpuctx->ctx.mutex, &cpuctx_mutex);
7604 lockdep_set_class(&cpuctx->ctx.lock, &cpuctx_lock);
7605 cpuctx->ctx.pmu = pmu;
7607 __perf_mux_hrtimer_init(cpuctx, cpu);
7609 cpuctx->unique_pmu = pmu;
7613 if (!pmu->start_txn) {
7614 if (pmu->pmu_enable) {
7616 * If we have pmu_enable/pmu_disable calls, install
7617 * transaction stubs that use that to try and batch
7618 * hardware accesses.
7620 pmu->start_txn = perf_pmu_start_txn;
7621 pmu->commit_txn = perf_pmu_commit_txn;
7622 pmu->cancel_txn = perf_pmu_cancel_txn;
7624 pmu->start_txn = perf_pmu_nop_txn;
7625 pmu->commit_txn = perf_pmu_nop_int;
7626 pmu->cancel_txn = perf_pmu_nop_void;
7630 if (!pmu->pmu_enable) {
7631 pmu->pmu_enable = perf_pmu_nop_void;
7632 pmu->pmu_disable = perf_pmu_nop_void;
7635 if (!pmu->event_idx)
7636 pmu->event_idx = perf_event_idx_default;
7638 list_add_rcu(&pmu->entry, &pmus);
7639 atomic_set(&pmu->exclusive_cnt, 0);
7642 mutex_unlock(&pmus_lock);
7647 device_del(pmu->dev);
7648 put_device(pmu->dev);
7651 if (pmu->type >= PERF_TYPE_MAX)
7652 idr_remove(&pmu_idr, pmu->type);
7655 free_percpu(pmu->pmu_disable_count);
7658 EXPORT_SYMBOL_GPL(perf_pmu_register);
7660 void perf_pmu_unregister(struct pmu *pmu)
7662 mutex_lock(&pmus_lock);
7663 list_del_rcu(&pmu->entry);
7664 mutex_unlock(&pmus_lock);
7667 * We dereference the pmu list under both SRCU and regular RCU, so
7668 * synchronize against both of those.
7670 synchronize_srcu(&pmus_srcu);
7673 free_percpu(pmu->pmu_disable_count);
7674 if (pmu->type >= PERF_TYPE_MAX)
7675 idr_remove(&pmu_idr, pmu->type);
7676 device_del(pmu->dev);
7677 put_device(pmu->dev);
7678 free_pmu_context(pmu);
7680 EXPORT_SYMBOL_GPL(perf_pmu_unregister);
7682 static int perf_try_init_event(struct pmu *pmu, struct perf_event *event)
7684 struct perf_event_context *ctx = NULL;
7687 if (!try_module_get(pmu->module))
7690 if (event->group_leader != event) {
7692 * This ctx->mutex can nest when we're called through
7693 * inheritance. See the perf_event_ctx_lock_nested() comment.
7695 ctx = perf_event_ctx_lock_nested(event->group_leader,
7696 SINGLE_DEPTH_NESTING);
7701 ret = pmu->event_init(event);
7704 perf_event_ctx_unlock(event->group_leader, ctx);
7707 module_put(pmu->module);
7712 static struct pmu *perf_init_event(struct perf_event *event)
7714 struct pmu *pmu = NULL;
7718 idx = srcu_read_lock(&pmus_srcu);
7721 pmu = idr_find(&pmu_idr, event->attr.type);
7724 ret = perf_try_init_event(pmu, event);
7730 list_for_each_entry_rcu(pmu, &pmus, entry) {
7731 ret = perf_try_init_event(pmu, event);
7735 if (ret != -ENOENT) {
7740 pmu = ERR_PTR(-ENOENT);
7742 srcu_read_unlock(&pmus_srcu, idx);
7747 static void account_event_cpu(struct perf_event *event, int cpu)
7752 if (is_cgroup_event(event))
7753 atomic_inc(&per_cpu(perf_cgroup_events, cpu));
7756 static void account_event(struct perf_event *event)
7763 if (event->attach_state & PERF_ATTACH_TASK)
7765 if (event->attr.mmap || event->attr.mmap_data)
7766 atomic_inc(&nr_mmap_events);
7767 if (event->attr.comm)
7768 atomic_inc(&nr_comm_events);
7769 if (event->attr.task)
7770 atomic_inc(&nr_task_events);
7771 if (event->attr.freq) {
7772 if (atomic_inc_return(&nr_freq_events) == 1)
7773 tick_nohz_full_kick_all();
7775 if (event->attr.context_switch) {
7776 atomic_inc(&nr_switch_events);
7779 if (has_branch_stack(event))
7781 if (is_cgroup_event(event))
7785 static_key_slow_inc(&perf_sched_events.key);
7787 account_event_cpu(event, event->cpu);
7791 * Allocate and initialize a event structure
7793 static struct perf_event *
7794 perf_event_alloc(struct perf_event_attr *attr, int cpu,
7795 struct task_struct *task,
7796 struct perf_event *group_leader,
7797 struct perf_event *parent_event,
7798 perf_overflow_handler_t overflow_handler,
7799 void *context, int cgroup_fd)
7802 struct perf_event *event;
7803 struct hw_perf_event *hwc;
7806 if ((unsigned)cpu >= nr_cpu_ids) {
7807 if (!task || cpu != -1)
7808 return ERR_PTR(-EINVAL);
7811 event = kzalloc(sizeof(*event), GFP_KERNEL);
7813 return ERR_PTR(-ENOMEM);
7816 * Single events are their own group leaders, with an
7817 * empty sibling list:
7820 group_leader = event;
7822 mutex_init(&event->child_mutex);
7823 INIT_LIST_HEAD(&event->child_list);
7825 INIT_LIST_HEAD(&event->group_entry);
7826 INIT_LIST_HEAD(&event->event_entry);
7827 INIT_LIST_HEAD(&event->sibling_list);
7828 INIT_LIST_HEAD(&event->rb_entry);
7829 INIT_LIST_HEAD(&event->active_entry);
7830 INIT_HLIST_NODE(&event->hlist_entry);
7833 init_waitqueue_head(&event->waitq);
7834 init_irq_work(&event->pending, perf_pending_event);
7836 mutex_init(&event->mmap_mutex);
7838 atomic_long_set(&event->refcount, 1);
7840 event->attr = *attr;
7841 event->group_leader = group_leader;
7845 event->parent = parent_event;
7847 event->ns = get_pid_ns(task_active_pid_ns(current));
7848 event->id = atomic64_inc_return(&perf_event_id);
7850 event->state = PERF_EVENT_STATE_INACTIVE;
7853 event->attach_state = PERF_ATTACH_TASK;
7855 * XXX pmu::event_init needs to know what task to account to
7856 * and we cannot use the ctx information because we need the
7857 * pmu before we get a ctx.
7859 event->hw.target = task;
7862 event->clock = &local_clock;
7864 event->clock = parent_event->clock;
7866 if (!overflow_handler && parent_event) {
7867 overflow_handler = parent_event->overflow_handler;
7868 context = parent_event->overflow_handler_context;
7871 event->overflow_handler = overflow_handler;
7872 event->overflow_handler_context = context;
7874 perf_event__state_init(event);
7879 hwc->sample_period = attr->sample_period;
7880 if (attr->freq && attr->sample_freq)
7881 hwc->sample_period = 1;
7882 hwc->last_period = hwc->sample_period;
7884 local64_set(&hwc->period_left, hwc->sample_period);
7887 * we currently do not support PERF_FORMAT_GROUP on inherited events
7889 if (attr->inherit && (attr->read_format & PERF_FORMAT_GROUP))
7892 if (!has_branch_stack(event))
7893 event->attr.branch_sample_type = 0;
7895 if (cgroup_fd != -1) {
7896 err = perf_cgroup_connect(cgroup_fd, event, attr, group_leader);
7901 pmu = perf_init_event(event);
7904 else if (IS_ERR(pmu)) {
7909 err = exclusive_event_init(event);
7913 if (!event->parent) {
7914 if (event->attr.sample_type & PERF_SAMPLE_CALLCHAIN) {
7915 err = get_callchain_buffers();
7924 exclusive_event_destroy(event);
7928 event->destroy(event);
7929 module_put(pmu->module);
7931 if (is_cgroup_event(event))
7932 perf_detach_cgroup(event);
7934 put_pid_ns(event->ns);
7937 return ERR_PTR(err);
7940 static int perf_copy_attr(struct perf_event_attr __user *uattr,
7941 struct perf_event_attr *attr)
7946 if (!access_ok(VERIFY_WRITE, uattr, PERF_ATTR_SIZE_VER0))
7950 * zero the full structure, so that a short copy will be nice.
7952 memset(attr, 0, sizeof(*attr));
7954 ret = get_user(size, &uattr->size);
7958 if (size > PAGE_SIZE) /* silly large */
7961 if (!size) /* abi compat */
7962 size = PERF_ATTR_SIZE_VER0;
7964 if (size < PERF_ATTR_SIZE_VER0)
7968 * If we're handed a bigger struct than we know of,
7969 * ensure all the unknown bits are 0 - i.e. new
7970 * user-space does not rely on any kernel feature
7971 * extensions we dont know about yet.
7973 if (size > sizeof(*attr)) {
7974 unsigned char __user *addr;
7975 unsigned char __user *end;
7978 addr = (void __user *)uattr + sizeof(*attr);
7979 end = (void __user *)uattr + size;
7981 for (; addr < end; addr++) {
7982 ret = get_user(val, addr);
7988 size = sizeof(*attr);
7991 ret = copy_from_user(attr, uattr, size);
7995 if (attr->__reserved_1)
7998 if (attr->sample_type & ~(PERF_SAMPLE_MAX-1))
8001 if (attr->read_format & ~(PERF_FORMAT_MAX-1))
8004 if (attr->sample_type & PERF_SAMPLE_BRANCH_STACK) {
8005 u64 mask = attr->branch_sample_type;
8007 /* only using defined bits */
8008 if (mask & ~(PERF_SAMPLE_BRANCH_MAX-1))
8011 /* at least one branch bit must be set */
8012 if (!(mask & ~PERF_SAMPLE_BRANCH_PLM_ALL))
8015 /* propagate priv level, when not set for branch */
8016 if (!(mask & PERF_SAMPLE_BRANCH_PLM_ALL)) {
8018 /* exclude_kernel checked on syscall entry */
8019 if (!attr->exclude_kernel)
8020 mask |= PERF_SAMPLE_BRANCH_KERNEL;
8022 if (!attr->exclude_user)
8023 mask |= PERF_SAMPLE_BRANCH_USER;
8025 if (!attr->exclude_hv)
8026 mask |= PERF_SAMPLE_BRANCH_HV;
8028 * adjust user setting (for HW filter setup)
8030 attr->branch_sample_type = mask;
8032 /* privileged levels capture (kernel, hv): check permissions */
8033 if ((mask & PERF_SAMPLE_BRANCH_PERM_PLM)
8034 && perf_paranoid_kernel() && !capable(CAP_SYS_ADMIN))
8038 if (attr->sample_type & PERF_SAMPLE_REGS_USER) {
8039 ret = perf_reg_validate(attr->sample_regs_user);
8044 if (attr->sample_type & PERF_SAMPLE_STACK_USER) {
8045 if (!arch_perf_have_user_stack_dump())
8049 * We have __u32 type for the size, but so far
8050 * we can only use __u16 as maximum due to the
8051 * __u16 sample size limit.
8053 if (attr->sample_stack_user >= USHRT_MAX)
8055 else if (!IS_ALIGNED(attr->sample_stack_user, sizeof(u64)))
8059 if (attr->sample_type & PERF_SAMPLE_REGS_INTR)
8060 ret = perf_reg_validate(attr->sample_regs_intr);
8065 put_user(sizeof(*attr), &uattr->size);
8071 perf_event_set_output(struct perf_event *event, struct perf_event *output_event)
8073 struct ring_buffer *rb = NULL;
8079 /* don't allow circular references */
8080 if (event == output_event)
8084 * Don't allow cross-cpu buffers
8086 if (output_event->cpu != event->cpu)
8090 * If its not a per-cpu rb, it must be the same task.
8092 if (output_event->cpu == -1 && output_event->ctx != event->ctx)
8096 * Mixing clocks in the same buffer is trouble you don't need.
8098 if (output_event->clock != event->clock)
8102 * If both events generate aux data, they must be on the same PMU
8104 if (has_aux(event) && has_aux(output_event) &&
8105 event->pmu != output_event->pmu)
8109 mutex_lock(&event->mmap_mutex);
8110 /* Can't redirect output if we've got an active mmap() */
8111 if (atomic_read(&event->mmap_count))
8115 /* get the rb we want to redirect to */
8116 rb = ring_buffer_get(output_event);
8121 ring_buffer_attach(event, rb);
8125 mutex_unlock(&event->mmap_mutex);
8131 static void mutex_lock_double(struct mutex *a, struct mutex *b)
8137 mutex_lock_nested(b, SINGLE_DEPTH_NESTING);
8140 static int perf_event_set_clock(struct perf_event *event, clockid_t clk_id)
8142 bool nmi_safe = false;
8145 case CLOCK_MONOTONIC:
8146 event->clock = &ktime_get_mono_fast_ns;
8150 case CLOCK_MONOTONIC_RAW:
8151 event->clock = &ktime_get_raw_fast_ns;
8155 case CLOCK_REALTIME:
8156 event->clock = &ktime_get_real_ns;
8159 case CLOCK_BOOTTIME:
8160 event->clock = &ktime_get_boot_ns;
8164 event->clock = &ktime_get_tai_ns;
8171 if (!nmi_safe && !(event->pmu->capabilities & PERF_PMU_CAP_NO_NMI))
8178 * sys_perf_event_open - open a performance event, associate it to a task/cpu
8180 * @attr_uptr: event_id type attributes for monitoring/sampling
8183 * @group_fd: group leader event fd
8185 SYSCALL_DEFINE5(perf_event_open,
8186 struct perf_event_attr __user *, attr_uptr,
8187 pid_t, pid, int, cpu, int, group_fd, unsigned long, flags)
8189 struct perf_event *group_leader = NULL, *output_event = NULL;
8190 struct perf_event *event, *sibling;
8191 struct perf_event_attr attr;
8192 struct perf_event_context *ctx, *uninitialized_var(gctx);
8193 struct file *event_file = NULL;
8194 struct fd group = {NULL, 0};
8195 struct task_struct *task = NULL;
8200 int f_flags = O_RDWR;
8203 /* for future expandability... */
8204 if (flags & ~PERF_FLAG_ALL)
8207 err = perf_copy_attr(attr_uptr, &attr);
8211 if (!attr.exclude_kernel) {
8212 if (perf_paranoid_kernel() && !capable(CAP_SYS_ADMIN))
8217 if (attr.sample_freq > sysctl_perf_event_sample_rate)
8220 if (attr.sample_period & (1ULL << 63))
8225 * In cgroup mode, the pid argument is used to pass the fd
8226 * opened to the cgroup directory in cgroupfs. The cpu argument
8227 * designates the cpu on which to monitor threads from that
8230 if ((flags & PERF_FLAG_PID_CGROUP) && (pid == -1 || cpu == -1))
8233 if (flags & PERF_FLAG_FD_CLOEXEC)
8234 f_flags |= O_CLOEXEC;
8236 event_fd = get_unused_fd_flags(f_flags);
8240 if (group_fd != -1) {
8241 err = perf_fget_light(group_fd, &group);
8244 group_leader = group.file->private_data;
8245 if (flags & PERF_FLAG_FD_OUTPUT)
8246 output_event = group_leader;
8247 if (flags & PERF_FLAG_FD_NO_GROUP)
8248 group_leader = NULL;
8251 if (pid != -1 && !(flags & PERF_FLAG_PID_CGROUP)) {
8252 task = find_lively_task_by_vpid(pid);
8254 err = PTR_ERR(task);
8259 if (task && group_leader &&
8260 group_leader->attr.inherit != attr.inherit) {
8267 if (flags & PERF_FLAG_PID_CGROUP)
8270 event = perf_event_alloc(&attr, cpu, task, group_leader, NULL,
8271 NULL, NULL, cgroup_fd);
8272 if (IS_ERR(event)) {
8273 err = PTR_ERR(event);
8277 if (is_sampling_event(event)) {
8278 if (event->pmu->capabilities & PERF_PMU_CAP_NO_INTERRUPT) {
8284 account_event(event);
8287 * Special case software events and allow them to be part of
8288 * any hardware group.
8292 if (attr.use_clockid) {
8293 err = perf_event_set_clock(event, attr.clockid);
8299 (is_software_event(event) != is_software_event(group_leader))) {
8300 if (is_software_event(event)) {
8302 * If event and group_leader are not both a software
8303 * event, and event is, then group leader is not.
8305 * Allow the addition of software events to !software
8306 * groups, this is safe because software events never
8309 pmu = group_leader->pmu;
8310 } else if (is_software_event(group_leader) &&
8311 (group_leader->group_flags & PERF_GROUP_SOFTWARE)) {
8313 * In case the group is a pure software group, and we
8314 * try to add a hardware event, move the whole group to
8315 * the hardware context.
8322 * Get the target context (task or percpu):
8324 ctx = find_get_context(pmu, task, event);
8330 if ((pmu->capabilities & PERF_PMU_CAP_EXCLUSIVE) && group_leader) {
8336 put_task_struct(task);
8341 * Look up the group leader (we will attach this event to it):
8347 * Do not allow a recursive hierarchy (this new sibling
8348 * becoming part of another group-sibling):
8350 if (group_leader->group_leader != group_leader)
8353 /* All events in a group should have the same clock */
8354 if (group_leader->clock != event->clock)
8358 * Do not allow to attach to a group in a different
8359 * task or CPU context:
8363 * Make sure we're both on the same task, or both
8366 if (group_leader->ctx->task != ctx->task)
8370 * Make sure we're both events for the same CPU;
8371 * grouping events for different CPUs is broken; since
8372 * you can never concurrently schedule them anyhow.
8374 if (group_leader->cpu != event->cpu)
8377 if (group_leader->ctx != ctx)
8382 * Only a group leader can be exclusive or pinned
8384 if (attr.exclusive || attr.pinned)
8389 err = perf_event_set_output(event, output_event);
8394 event_file = anon_inode_getfile("[perf_event]", &perf_fops, event,
8396 if (IS_ERR(event_file)) {
8397 err = PTR_ERR(event_file);
8402 gctx = group_leader->ctx;
8403 mutex_lock_double(&gctx->mutex, &ctx->mutex);
8404 if (gctx->task == TASK_TOMBSTONE) {
8409 mutex_lock(&ctx->mutex);
8412 if (ctx->task == TASK_TOMBSTONE) {
8417 if (!perf_event_validate_size(event)) {
8423 * Must be under the same ctx::mutex as perf_install_in_context(),
8424 * because we need to serialize with concurrent event creation.
8426 if (!exclusive_event_installable(event, ctx)) {
8427 /* exclusive and group stuff are assumed mutually exclusive */
8428 WARN_ON_ONCE(move_group);
8434 WARN_ON_ONCE(ctx->parent_ctx);
8438 * See perf_event_ctx_lock() for comments on the details
8439 * of swizzling perf_event::ctx.
8441 perf_remove_from_context(group_leader, 0);
8443 list_for_each_entry(sibling, &group_leader->sibling_list,
8445 perf_remove_from_context(sibling, 0);
8450 * Wait for everybody to stop referencing the events through
8451 * the old lists, before installing it on new lists.
8456 * Install the group siblings before the group leader.
8458 * Because a group leader will try and install the entire group
8459 * (through the sibling list, which is still in-tact), we can
8460 * end up with siblings installed in the wrong context.
8462 * By installing siblings first we NO-OP because they're not
8463 * reachable through the group lists.
8465 list_for_each_entry(sibling, &group_leader->sibling_list,
8467 perf_event__state_init(sibling);
8468 perf_install_in_context(ctx, sibling, sibling->cpu);
8473 * Removing from the context ends up with disabled
8474 * event. What we want here is event in the initial
8475 * startup state, ready to be add into new context.
8477 perf_event__state_init(group_leader);
8478 perf_install_in_context(ctx, group_leader, group_leader->cpu);
8482 * Now that all events are installed in @ctx, nothing
8483 * references @gctx anymore, so drop the last reference we have
8490 * Precalculate sample_data sizes; do while holding ctx::mutex such
8491 * that we're serialized against further additions and before
8492 * perf_install_in_context() which is the point the event is active and
8493 * can use these values.
8495 perf_event__header_size(event);
8496 perf_event__id_header_size(event);
8498 event->owner = current;
8500 perf_install_in_context(ctx, event, event->cpu);
8501 perf_unpin_context(ctx);
8504 mutex_unlock(&gctx->mutex);
8505 mutex_unlock(&ctx->mutex);
8509 mutex_lock(¤t->perf_event_mutex);
8510 list_add_tail(&event->owner_entry, ¤t->perf_event_list);
8511 mutex_unlock(¤t->perf_event_mutex);
8514 * Drop the reference on the group_event after placing the
8515 * new event on the sibling_list. This ensures destruction
8516 * of the group leader will find the pointer to itself in
8517 * perf_group_detach().
8520 fd_install(event_fd, event_file);
8525 mutex_unlock(&gctx->mutex);
8526 mutex_unlock(&ctx->mutex);
8530 perf_unpin_context(ctx);
8534 * If event_file is set, the fput() above will have called ->release()
8535 * and that will take care of freeing the event.
8543 put_task_struct(task);
8547 put_unused_fd(event_fd);
8552 * perf_event_create_kernel_counter
8554 * @attr: attributes of the counter to create
8555 * @cpu: cpu in which the counter is bound
8556 * @task: task to profile (NULL for percpu)
8559 perf_event_create_kernel_counter(struct perf_event_attr *attr, int cpu,
8560 struct task_struct *task,
8561 perf_overflow_handler_t overflow_handler,
8564 struct perf_event_context *ctx;
8565 struct perf_event *event;
8569 * Get the target context (task or percpu):
8572 event = perf_event_alloc(attr, cpu, task, NULL, NULL,
8573 overflow_handler, context, -1);
8574 if (IS_ERR(event)) {
8575 err = PTR_ERR(event);
8579 /* Mark owner so we could distinguish it from user events. */
8580 event->owner = TASK_TOMBSTONE;
8582 account_event(event);
8584 ctx = find_get_context(event->pmu, task, event);
8590 WARN_ON_ONCE(ctx->parent_ctx);
8591 mutex_lock(&ctx->mutex);
8592 if (ctx->task == TASK_TOMBSTONE) {
8597 if (!exclusive_event_installable(event, ctx)) {
8602 perf_install_in_context(ctx, event, cpu);
8603 perf_unpin_context(ctx);
8604 mutex_unlock(&ctx->mutex);
8609 mutex_unlock(&ctx->mutex);
8610 perf_unpin_context(ctx);
8615 return ERR_PTR(err);
8617 EXPORT_SYMBOL_GPL(perf_event_create_kernel_counter);
8619 void perf_pmu_migrate_context(struct pmu *pmu, int src_cpu, int dst_cpu)
8621 struct perf_event_context *src_ctx;
8622 struct perf_event_context *dst_ctx;
8623 struct perf_event *event, *tmp;
8626 src_ctx = &per_cpu_ptr(pmu->pmu_cpu_context, src_cpu)->ctx;
8627 dst_ctx = &per_cpu_ptr(pmu->pmu_cpu_context, dst_cpu)->ctx;
8630 * See perf_event_ctx_lock() for comments on the details
8631 * of swizzling perf_event::ctx.
8633 mutex_lock_double(&src_ctx->mutex, &dst_ctx->mutex);
8634 list_for_each_entry_safe(event, tmp, &src_ctx->event_list,
8636 perf_remove_from_context(event, 0);
8637 unaccount_event_cpu(event, src_cpu);
8639 list_add(&event->migrate_entry, &events);
8643 * Wait for the events to quiesce before re-instating them.
8648 * Re-instate events in 2 passes.
8650 * Skip over group leaders and only install siblings on this first
8651 * pass, siblings will not get enabled without a leader, however a
8652 * leader will enable its siblings, even if those are still on the old
8655 list_for_each_entry_safe(event, tmp, &events, migrate_entry) {
8656 if (event->group_leader == event)
8659 list_del(&event->migrate_entry);
8660 if (event->state >= PERF_EVENT_STATE_OFF)
8661 event->state = PERF_EVENT_STATE_INACTIVE;
8662 account_event_cpu(event, dst_cpu);
8663 perf_install_in_context(dst_ctx, event, dst_cpu);
8668 * Once all the siblings are setup properly, install the group leaders
8671 list_for_each_entry_safe(event, tmp, &events, migrate_entry) {
8672 list_del(&event->migrate_entry);
8673 if (event->state >= PERF_EVENT_STATE_OFF)
8674 event->state = PERF_EVENT_STATE_INACTIVE;
8675 account_event_cpu(event, dst_cpu);
8676 perf_install_in_context(dst_ctx, event, dst_cpu);
8679 mutex_unlock(&dst_ctx->mutex);
8680 mutex_unlock(&src_ctx->mutex);
8682 EXPORT_SYMBOL_GPL(perf_pmu_migrate_context);
8684 static void sync_child_event(struct perf_event *child_event,
8685 struct task_struct *child)
8687 struct perf_event *parent_event = child_event->parent;
8690 if (child_event->attr.inherit_stat)
8691 perf_event_read_event(child_event, child);
8693 child_val = perf_event_count(child_event);
8696 * Add back the child's count to the parent's count:
8698 atomic64_add(child_val, &parent_event->child_count);
8699 atomic64_add(child_event->total_time_enabled,
8700 &parent_event->child_total_time_enabled);
8701 atomic64_add(child_event->total_time_running,
8702 &parent_event->child_total_time_running);
8706 perf_event_exit_event(struct perf_event *child_event,
8707 struct perf_event_context *child_ctx,
8708 struct task_struct *child)
8710 struct perf_event *parent_event = child_event->parent;
8713 * Do not destroy the 'original' grouping; because of the context
8714 * switch optimization the original events could've ended up in a
8715 * random child task.
8717 * If we were to destroy the original group, all group related
8718 * operations would cease to function properly after this random
8721 * Do destroy all inherited groups, we don't care about those
8722 * and being thorough is better.
8724 raw_spin_lock_irq(&child_ctx->lock);
8725 WARN_ON_ONCE(child_ctx->is_active);
8728 perf_group_detach(child_event);
8729 list_del_event(child_event, child_ctx);
8730 child_event->state = PERF_EVENT_STATE_EXIT; /* see perf_event_release_kernel() */
8731 raw_spin_unlock_irq(&child_ctx->lock);
8734 * Parent events are governed by their filedesc, retain them.
8736 if (!parent_event) {
8737 perf_event_wakeup(child_event);
8741 * Child events can be cleaned up.
8744 sync_child_event(child_event, child);
8747 * Remove this event from the parent's list
8749 WARN_ON_ONCE(parent_event->ctx->parent_ctx);
8750 mutex_lock(&parent_event->child_mutex);
8751 list_del_init(&child_event->child_list);
8752 mutex_unlock(&parent_event->child_mutex);
8755 * Kick perf_poll() for is_event_hup().
8757 perf_event_wakeup(parent_event);
8758 free_event(child_event);
8759 put_event(parent_event);
8762 static void perf_event_exit_task_context(struct task_struct *child, int ctxn)
8764 struct perf_event_context *child_ctx, *clone_ctx = NULL;
8765 struct perf_event *child_event, *next;
8767 WARN_ON_ONCE(child != current);
8769 child_ctx = perf_pin_task_context(child, ctxn);
8774 * In order to reduce the amount of tricky in ctx tear-down, we hold
8775 * ctx::mutex over the entire thing. This serializes against almost
8776 * everything that wants to access the ctx.
8778 * The exception is sys_perf_event_open() /
8779 * perf_event_create_kernel_count() which does find_get_context()
8780 * without ctx::mutex (it cannot because of the move_group double mutex
8781 * lock thing). See the comments in perf_install_in_context().
8783 mutex_lock(&child_ctx->mutex);
8786 * In a single ctx::lock section, de-schedule the events and detach the
8787 * context from the task such that we cannot ever get it scheduled back
8790 raw_spin_lock_irq(&child_ctx->lock);
8791 task_ctx_sched_out(__get_cpu_context(child_ctx), child_ctx);
8794 * Now that the context is inactive, destroy the task <-> ctx relation
8795 * and mark the context dead.
8797 RCU_INIT_POINTER(child->perf_event_ctxp[ctxn], NULL);
8798 put_ctx(child_ctx); /* cannot be last */
8799 WRITE_ONCE(child_ctx->task, TASK_TOMBSTONE);
8800 put_task_struct(current); /* cannot be last */
8802 clone_ctx = unclone_ctx(child_ctx);
8803 raw_spin_unlock_irq(&child_ctx->lock);
8809 * Report the task dead after unscheduling the events so that we
8810 * won't get any samples after PERF_RECORD_EXIT. We can however still
8811 * get a few PERF_RECORD_READ events.
8813 perf_event_task(child, child_ctx, 0);
8815 list_for_each_entry_safe(child_event, next, &child_ctx->event_list, event_entry)
8816 perf_event_exit_event(child_event, child_ctx, child);
8818 mutex_unlock(&child_ctx->mutex);
8824 * When a child task exits, feed back event values to parent events.
8826 void perf_event_exit_task(struct task_struct *child)
8828 struct perf_event *event, *tmp;
8831 mutex_lock(&child->perf_event_mutex);
8832 list_for_each_entry_safe(event, tmp, &child->perf_event_list,
8834 list_del_init(&event->owner_entry);
8837 * Ensure the list deletion is visible before we clear
8838 * the owner, closes a race against perf_release() where
8839 * we need to serialize on the owner->perf_event_mutex.
8841 smp_store_release(&event->owner, NULL);
8843 mutex_unlock(&child->perf_event_mutex);
8845 for_each_task_context_nr(ctxn)
8846 perf_event_exit_task_context(child, ctxn);
8849 * The perf_event_exit_task_context calls perf_event_task
8850 * with child's task_ctx, which generates EXIT events for
8851 * child contexts and sets child->perf_event_ctxp[] to NULL.
8852 * At this point we need to send EXIT events to cpu contexts.
8854 perf_event_task(child, NULL, 0);
8857 static void perf_free_event(struct perf_event *event,
8858 struct perf_event_context *ctx)
8860 struct perf_event *parent = event->parent;
8862 if (WARN_ON_ONCE(!parent))
8865 mutex_lock(&parent->child_mutex);
8866 list_del_init(&event->child_list);
8867 mutex_unlock(&parent->child_mutex);
8871 raw_spin_lock_irq(&ctx->lock);
8872 perf_group_detach(event);
8873 list_del_event(event, ctx);
8874 raw_spin_unlock_irq(&ctx->lock);
8879 * Free an unexposed, unused context as created by inheritance by
8880 * perf_event_init_task below, used by fork() in case of fail.
8882 * Not all locks are strictly required, but take them anyway to be nice and
8883 * help out with the lockdep assertions.
8885 void perf_event_free_task(struct task_struct *task)
8887 struct perf_event_context *ctx;
8888 struct perf_event *event, *tmp;
8891 for_each_task_context_nr(ctxn) {
8892 ctx = task->perf_event_ctxp[ctxn];
8896 mutex_lock(&ctx->mutex);
8898 list_for_each_entry_safe(event, tmp, &ctx->pinned_groups,
8900 perf_free_event(event, ctx);
8902 list_for_each_entry_safe(event, tmp, &ctx->flexible_groups,
8904 perf_free_event(event, ctx);
8906 if (!list_empty(&ctx->pinned_groups) ||
8907 !list_empty(&ctx->flexible_groups))
8910 mutex_unlock(&ctx->mutex);
8916 void perf_event_delayed_put(struct task_struct *task)
8920 for_each_task_context_nr(ctxn)
8921 WARN_ON_ONCE(task->perf_event_ctxp[ctxn]);
8924 struct file *perf_event_get(unsigned int fd)
8928 file = fget_raw(fd);
8930 return ERR_PTR(-EBADF);
8932 if (file->f_op != &perf_fops) {
8934 return ERR_PTR(-EBADF);
8940 const struct perf_event_attr *perf_event_attrs(struct perf_event *event)
8943 return ERR_PTR(-EINVAL);
8945 return &event->attr;
8949 * inherit a event from parent task to child task:
8951 static struct perf_event *
8952 inherit_event(struct perf_event *parent_event,
8953 struct task_struct *parent,
8954 struct perf_event_context *parent_ctx,
8955 struct task_struct *child,
8956 struct perf_event *group_leader,
8957 struct perf_event_context *child_ctx)
8959 enum perf_event_active_state parent_state = parent_event->state;
8960 struct perf_event *child_event;
8961 unsigned long flags;
8964 * Instead of creating recursive hierarchies of events,
8965 * we link inherited events back to the original parent,
8966 * which has a filp for sure, which we use as the reference
8969 if (parent_event->parent)
8970 parent_event = parent_event->parent;
8972 child_event = perf_event_alloc(&parent_event->attr,
8975 group_leader, parent_event,
8977 if (IS_ERR(child_event))
8981 * is_orphaned_event() and list_add_tail(&parent_event->child_list)
8982 * must be under the same lock in order to serialize against
8983 * perf_event_release_kernel(), such that either we must observe
8984 * is_orphaned_event() or they will observe us on the child_list.
8986 mutex_lock(&parent_event->child_mutex);
8987 if (is_orphaned_event(parent_event) ||
8988 !atomic_long_inc_not_zero(&parent_event->refcount)) {
8989 mutex_unlock(&parent_event->child_mutex);
8990 free_event(child_event);
8997 * Make the child state follow the state of the parent event,
8998 * not its attr.disabled bit. We hold the parent's mutex,
8999 * so we won't race with perf_event_{en, dis}able_family.
9001 if (parent_state >= PERF_EVENT_STATE_INACTIVE)
9002 child_event->state = PERF_EVENT_STATE_INACTIVE;
9004 child_event->state = PERF_EVENT_STATE_OFF;
9006 if (parent_event->attr.freq) {
9007 u64 sample_period = parent_event->hw.sample_period;
9008 struct hw_perf_event *hwc = &child_event->hw;
9010 hwc->sample_period = sample_period;
9011 hwc->last_period = sample_period;
9013 local64_set(&hwc->period_left, sample_period);
9016 child_event->ctx = child_ctx;
9017 child_event->overflow_handler = parent_event->overflow_handler;
9018 child_event->overflow_handler_context
9019 = parent_event->overflow_handler_context;
9022 * Precalculate sample_data sizes
9024 perf_event__header_size(child_event);
9025 perf_event__id_header_size(child_event);
9028 * Link it up in the child's context:
9030 raw_spin_lock_irqsave(&child_ctx->lock, flags);
9031 add_event_to_ctx(child_event, child_ctx);
9032 raw_spin_unlock_irqrestore(&child_ctx->lock, flags);
9035 * Link this into the parent event's child list
9037 list_add_tail(&child_event->child_list, &parent_event->child_list);
9038 mutex_unlock(&parent_event->child_mutex);
9043 static int inherit_group(struct perf_event *parent_event,
9044 struct task_struct *parent,
9045 struct perf_event_context *parent_ctx,
9046 struct task_struct *child,
9047 struct perf_event_context *child_ctx)
9049 struct perf_event *leader;
9050 struct perf_event *sub;
9051 struct perf_event *child_ctr;
9053 leader = inherit_event(parent_event, parent, parent_ctx,
9054 child, NULL, child_ctx);
9056 return PTR_ERR(leader);
9057 list_for_each_entry(sub, &parent_event->sibling_list, group_entry) {
9058 child_ctr = inherit_event(sub, parent, parent_ctx,
9059 child, leader, child_ctx);
9060 if (IS_ERR(child_ctr))
9061 return PTR_ERR(child_ctr);
9067 inherit_task_group(struct perf_event *event, struct task_struct *parent,
9068 struct perf_event_context *parent_ctx,
9069 struct task_struct *child, int ctxn,
9073 struct perf_event_context *child_ctx;
9075 if (!event->attr.inherit) {
9080 child_ctx = child->perf_event_ctxp[ctxn];
9083 * This is executed from the parent task context, so
9084 * inherit events that have been marked for cloning.
9085 * First allocate and initialize a context for the
9089 child_ctx = alloc_perf_context(parent_ctx->pmu, child);
9093 child->perf_event_ctxp[ctxn] = child_ctx;
9096 ret = inherit_group(event, parent, parent_ctx,
9106 * Initialize the perf_event context in task_struct
9108 static int perf_event_init_context(struct task_struct *child, int ctxn)
9110 struct perf_event_context *child_ctx, *parent_ctx;
9111 struct perf_event_context *cloned_ctx;
9112 struct perf_event *event;
9113 struct task_struct *parent = current;
9114 int inherited_all = 1;
9115 unsigned long flags;
9118 if (likely(!parent->perf_event_ctxp[ctxn]))
9122 * If the parent's context is a clone, pin it so it won't get
9125 parent_ctx = perf_pin_task_context(parent, ctxn);
9130 * No need to check if parent_ctx != NULL here; since we saw
9131 * it non-NULL earlier, the only reason for it to become NULL
9132 * is if we exit, and since we're currently in the middle of
9133 * a fork we can't be exiting at the same time.
9137 * Lock the parent list. No need to lock the child - not PID
9138 * hashed yet and not running, so nobody can access it.
9140 mutex_lock(&parent_ctx->mutex);
9143 * We dont have to disable NMIs - we are only looking at
9144 * the list, not manipulating it:
9146 list_for_each_entry(event, &parent_ctx->pinned_groups, group_entry) {
9147 ret = inherit_task_group(event, parent, parent_ctx,
9148 child, ctxn, &inherited_all);
9154 * We can't hold ctx->lock when iterating the ->flexible_group list due
9155 * to allocations, but we need to prevent rotation because
9156 * rotate_ctx() will change the list from interrupt context.
9158 raw_spin_lock_irqsave(&parent_ctx->lock, flags);
9159 parent_ctx->rotate_disable = 1;
9160 raw_spin_unlock_irqrestore(&parent_ctx->lock, flags);
9162 list_for_each_entry(event, &parent_ctx->flexible_groups, group_entry) {
9163 ret = inherit_task_group(event, parent, parent_ctx,
9164 child, ctxn, &inherited_all);
9169 raw_spin_lock_irqsave(&parent_ctx->lock, flags);
9170 parent_ctx->rotate_disable = 0;
9172 child_ctx = child->perf_event_ctxp[ctxn];
9174 if (child_ctx && inherited_all) {
9176 * Mark the child context as a clone of the parent
9177 * context, or of whatever the parent is a clone of.
9179 * Note that if the parent is a clone, the holding of
9180 * parent_ctx->lock avoids it from being uncloned.
9182 cloned_ctx = parent_ctx->parent_ctx;
9184 child_ctx->parent_ctx = cloned_ctx;
9185 child_ctx->parent_gen = parent_ctx->parent_gen;
9187 child_ctx->parent_ctx = parent_ctx;
9188 child_ctx->parent_gen = parent_ctx->generation;
9190 get_ctx(child_ctx->parent_ctx);
9193 raw_spin_unlock_irqrestore(&parent_ctx->lock, flags);
9194 mutex_unlock(&parent_ctx->mutex);
9196 perf_unpin_context(parent_ctx);
9197 put_ctx(parent_ctx);
9203 * Initialize the perf_event context in task_struct
9205 int perf_event_init_task(struct task_struct *child)
9209 memset(child->perf_event_ctxp, 0, sizeof(child->perf_event_ctxp));
9210 mutex_init(&child->perf_event_mutex);
9211 INIT_LIST_HEAD(&child->perf_event_list);
9213 for_each_task_context_nr(ctxn) {
9214 ret = perf_event_init_context(child, ctxn);
9216 perf_event_free_task(child);
9224 static void __init perf_event_init_all_cpus(void)
9226 struct swevent_htable *swhash;
9229 for_each_possible_cpu(cpu) {
9230 swhash = &per_cpu(swevent_htable, cpu);
9231 mutex_init(&swhash->hlist_mutex);
9232 INIT_LIST_HEAD(&per_cpu(active_ctx_list, cpu));
9236 static void perf_event_init_cpu(int cpu)
9238 struct swevent_htable *swhash = &per_cpu(swevent_htable, cpu);
9240 mutex_lock(&swhash->hlist_mutex);
9241 if (swhash->hlist_refcount > 0 && !swevent_hlist_deref(swhash)) {
9242 struct swevent_hlist *hlist;
9244 hlist = kzalloc_node(sizeof(*hlist), GFP_KERNEL, cpu_to_node(cpu));
9246 rcu_assign_pointer(swhash->swevent_hlist, hlist);
9248 mutex_unlock(&swhash->hlist_mutex);
9251 #if defined CONFIG_HOTPLUG_CPU || defined CONFIG_KEXEC_CORE
9252 static void __perf_event_exit_context(void *__info)
9254 struct perf_event_context *ctx = __info;
9255 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
9256 struct perf_event *event;
9258 raw_spin_lock(&ctx->lock);
9259 list_for_each_entry(event, &ctx->event_list, event_entry)
9260 __perf_remove_from_context(event, cpuctx, ctx, (void *)DETACH_GROUP);
9261 raw_spin_unlock(&ctx->lock);
9264 static void perf_event_exit_cpu_context(int cpu)
9266 struct perf_event_context *ctx;
9270 idx = srcu_read_lock(&pmus_srcu);
9271 list_for_each_entry_rcu(pmu, &pmus, entry) {
9272 ctx = &per_cpu_ptr(pmu->pmu_cpu_context, cpu)->ctx;
9274 mutex_lock(&ctx->mutex);
9275 smp_call_function_single(cpu, __perf_event_exit_context, ctx, 1);
9276 mutex_unlock(&ctx->mutex);
9278 srcu_read_unlock(&pmus_srcu, idx);
9281 static void perf_event_exit_cpu(int cpu)
9283 perf_event_exit_cpu_context(cpu);
9286 static inline void perf_event_exit_cpu(int cpu) { }
9290 perf_reboot(struct notifier_block *notifier, unsigned long val, void *v)
9294 for_each_online_cpu(cpu)
9295 perf_event_exit_cpu(cpu);
9301 * Run the perf reboot notifier at the very last possible moment so that
9302 * the generic watchdog code runs as long as possible.
9304 static struct notifier_block perf_reboot_notifier = {
9305 .notifier_call = perf_reboot,
9306 .priority = INT_MIN,
9310 perf_cpu_notify(struct notifier_block *self, unsigned long action, void *hcpu)
9312 unsigned int cpu = (long)hcpu;
9314 switch (action & ~CPU_TASKS_FROZEN) {
9316 case CPU_UP_PREPARE:
9317 perf_event_init_cpu(cpu);
9320 case CPU_DOWN_PREPARE:
9321 perf_event_exit_cpu(cpu);
9330 void __init perf_event_init(void)
9336 perf_event_init_all_cpus();
9337 init_srcu_struct(&pmus_srcu);
9338 perf_pmu_register(&perf_swevent, "software", PERF_TYPE_SOFTWARE);
9339 perf_pmu_register(&perf_cpu_clock, NULL, -1);
9340 perf_pmu_register(&perf_task_clock, NULL, -1);
9342 perf_cpu_notifier(perf_cpu_notify);
9343 register_reboot_notifier(&perf_reboot_notifier);
9345 ret = init_hw_breakpoint();
9346 WARN(ret, "hw_breakpoint initialization failed with: %d", ret);
9348 /* do not patch jump label more than once per second */
9349 jump_label_rate_limit(&perf_sched_events, HZ);
9352 * Build time assertion that we keep the data_head at the intended
9353 * location. IOW, validation we got the __reserved[] size right.
9355 BUILD_BUG_ON((offsetof(struct perf_event_mmap_page, data_head))
9359 ssize_t perf_event_sysfs_show(struct device *dev, struct device_attribute *attr,
9362 struct perf_pmu_events_attr *pmu_attr =
9363 container_of(attr, struct perf_pmu_events_attr, attr);
9365 if (pmu_attr->event_str)
9366 return sprintf(page, "%s\n", pmu_attr->event_str);
9371 static int __init perf_event_sysfs_init(void)
9376 mutex_lock(&pmus_lock);
9378 ret = bus_register(&pmu_bus);
9382 list_for_each_entry(pmu, &pmus, entry) {
9383 if (!pmu->name || pmu->type < 0)
9386 ret = pmu_dev_alloc(pmu);
9387 WARN(ret, "Failed to register pmu: %s, reason %d\n", pmu->name, ret);
9389 pmu_bus_running = 1;
9393 mutex_unlock(&pmus_lock);
9397 device_initcall(perf_event_sysfs_init);
9399 #ifdef CONFIG_CGROUP_PERF
9400 static struct cgroup_subsys_state *
9401 perf_cgroup_css_alloc(struct cgroup_subsys_state *parent_css)
9403 struct perf_cgroup *jc;
9405 jc = kzalloc(sizeof(*jc), GFP_KERNEL);
9407 return ERR_PTR(-ENOMEM);
9409 jc->info = alloc_percpu(struct perf_cgroup_info);
9412 return ERR_PTR(-ENOMEM);
9418 static void perf_cgroup_css_free(struct cgroup_subsys_state *css)
9420 struct perf_cgroup *jc = container_of(css, struct perf_cgroup, css);
9422 free_percpu(jc->info);
9426 static int __perf_cgroup_move(void *info)
9428 struct task_struct *task = info;
9430 perf_cgroup_switch(task, PERF_CGROUP_SWOUT | PERF_CGROUP_SWIN);
9435 static void perf_cgroup_attach(struct cgroup_taskset *tset)
9437 struct task_struct *task;
9438 struct cgroup_subsys_state *css;
9440 cgroup_taskset_for_each(task, css, tset)
9441 task_function_call(task, __perf_cgroup_move, task);
9444 struct cgroup_subsys perf_event_cgrp_subsys = {
9445 .css_alloc = perf_cgroup_css_alloc,
9446 .css_free = perf_cgroup_css_free,
9447 .attach = perf_cgroup_attach,
9449 #endif /* CONFIG_CGROUP_PERF */