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 static struct workqueue_struct *perf_wq;
54 typedef int (*remote_function_f)(void *);
56 struct remote_function_call {
57 struct task_struct *p;
58 remote_function_f func;
63 static void remote_function(void *data)
65 struct remote_function_call *tfc = data;
66 struct task_struct *p = tfc->p;
70 if (task_cpu(p) != smp_processor_id() || !task_curr(p))
74 tfc->ret = tfc->func(tfc->info);
78 * task_function_call - call a function on the cpu on which a task runs
79 * @p: the task to evaluate
80 * @func: the function to be called
81 * @info: the function call argument
83 * Calls the function @func when the task is currently running. This might
84 * be on the current CPU, which just calls the function directly
86 * returns: @func return value, or
87 * -ESRCH - when the process isn't running
88 * -EAGAIN - when the process moved away
91 task_function_call(struct task_struct *p, remote_function_f func, void *info)
93 struct remote_function_call data = {
97 .ret = -ESRCH, /* No such (running) process */
101 smp_call_function_single(task_cpu(p), remote_function, &data, 1);
107 * cpu_function_call - call a function on the cpu
108 * @func: the function to be called
109 * @info: the function call argument
111 * Calls the function @func on the remote cpu.
113 * returns: @func return value or -ENXIO when the cpu is offline
115 static int cpu_function_call(int cpu, remote_function_f func, void *info)
117 struct remote_function_call data = {
121 .ret = -ENXIO, /* No such CPU */
124 smp_call_function_single(cpu, remote_function, &data, 1);
129 static inline struct perf_cpu_context *
130 __get_cpu_context(struct perf_event_context *ctx)
132 return this_cpu_ptr(ctx->pmu->pmu_cpu_context);
135 static void perf_ctx_lock(struct perf_cpu_context *cpuctx,
136 struct perf_event_context *ctx)
138 raw_spin_lock(&cpuctx->ctx.lock);
140 raw_spin_lock(&ctx->lock);
143 static void perf_ctx_unlock(struct perf_cpu_context *cpuctx,
144 struct perf_event_context *ctx)
147 raw_spin_unlock(&ctx->lock);
148 raw_spin_unlock(&cpuctx->ctx.lock);
151 #define TASK_TOMBSTONE ((void *)-1L)
153 static bool is_kernel_event(struct perf_event *event)
155 return READ_ONCE(event->owner) == TASK_TOMBSTONE;
159 * On task ctx scheduling...
161 * When !ctx->nr_events a task context will not be scheduled. This means
162 * we can disable the scheduler hooks (for performance) without leaving
163 * pending task ctx state.
165 * This however results in two special cases:
167 * - removing the last event from a task ctx; this is relatively straight
168 * forward and is done in __perf_remove_from_context.
170 * - adding the first event to a task ctx; this is tricky because we cannot
171 * rely on ctx->is_active and therefore cannot use event_function_call().
172 * See perf_install_in_context().
174 * This is because we need a ctx->lock serialized variable (ctx->is_active)
175 * to reliably determine if a particular task/context is scheduled in. The
176 * task_curr() use in task_function_call() is racy in that a remote context
177 * switch is not a single atomic operation.
179 * As is, the situation is 'safe' because we set rq->curr before we do the
180 * actual context switch. This means that task_curr() will fail early, but
181 * we'll continue spinning on ctx->is_active until we've passed
182 * perf_event_task_sched_out().
184 * Without this ctx->lock serialized variable we could have race where we find
185 * the task (and hence the context) would not be active while in fact they are.
187 * If ctx->nr_events, then ctx->is_active and cpuctx->task_ctx are set.
190 typedef void (*event_f)(struct perf_event *, struct perf_cpu_context *,
191 struct perf_event_context *, void *);
193 struct event_function_struct {
194 struct perf_event *event;
199 static int event_function(void *info)
201 struct event_function_struct *efs = info;
202 struct perf_event *event = efs->event;
203 struct perf_event_context *ctx = event->ctx;
204 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
205 struct perf_event_context *task_ctx = cpuctx->task_ctx;
208 WARN_ON_ONCE(!irqs_disabled());
210 perf_ctx_lock(cpuctx, task_ctx);
212 * Since we do the IPI call without holding ctx->lock things can have
213 * changed, double check we hit the task we set out to hit.
216 if (ctx->task != current) {
222 * We only use event_function_call() on established contexts,
223 * and event_function() is only ever called when active (or
224 * rather, we'll have bailed in task_function_call() or the
225 * above ctx->task != current test), therefore we must have
226 * ctx->is_active here.
228 WARN_ON_ONCE(!ctx->is_active);
230 * And since we have ctx->is_active, cpuctx->task_ctx must
233 WARN_ON_ONCE(task_ctx != ctx);
235 WARN_ON_ONCE(&cpuctx->ctx != ctx);
238 efs->func(event, cpuctx, ctx, efs->data);
240 perf_ctx_unlock(cpuctx, task_ctx);
245 static void event_function_local(struct perf_event *event, event_f func, void *data)
247 struct event_function_struct efs = {
253 int ret = event_function(&efs);
257 static void event_function_call(struct perf_event *event, event_f func, void *data)
259 struct perf_event_context *ctx = event->ctx;
260 struct task_struct *task = READ_ONCE(ctx->task); /* verified in event_function */
261 struct event_function_struct efs = {
267 if (!event->parent) {
269 * If this is a !child event, we must hold ctx::mutex to
270 * stabilize the the event->ctx relation. See
271 * perf_event_ctx_lock().
273 lockdep_assert_held(&ctx->mutex);
277 cpu_function_call(event->cpu, event_function, &efs);
282 if (task == TASK_TOMBSTONE)
285 if (!task_function_call(task, event_function, &efs))
288 raw_spin_lock_irq(&ctx->lock);
290 * Reload the task pointer, it might have been changed by
291 * a concurrent perf_event_context_sched_out().
294 if (task != TASK_TOMBSTONE) {
295 if (ctx->is_active) {
296 raw_spin_unlock_irq(&ctx->lock);
299 func(event, NULL, ctx, data);
301 raw_spin_unlock_irq(&ctx->lock);
304 #define PERF_FLAG_ALL (PERF_FLAG_FD_NO_GROUP |\
305 PERF_FLAG_FD_OUTPUT |\
306 PERF_FLAG_PID_CGROUP |\
307 PERF_FLAG_FD_CLOEXEC)
310 * branch priv levels that need permission checks
312 #define PERF_SAMPLE_BRANCH_PERM_PLM \
313 (PERF_SAMPLE_BRANCH_KERNEL |\
314 PERF_SAMPLE_BRANCH_HV)
317 EVENT_FLEXIBLE = 0x1,
319 EVENT_ALL = EVENT_FLEXIBLE | EVENT_PINNED,
323 * perf_sched_events : >0 events exist
324 * perf_cgroup_events: >0 per-cpu cgroup events exist on this cpu
326 struct static_key_deferred perf_sched_events __read_mostly;
327 static DEFINE_PER_CPU(atomic_t, perf_cgroup_events);
328 static DEFINE_PER_CPU(int, perf_sched_cb_usages);
330 static atomic_t nr_mmap_events __read_mostly;
331 static atomic_t nr_comm_events __read_mostly;
332 static atomic_t nr_task_events __read_mostly;
333 static atomic_t nr_freq_events __read_mostly;
334 static atomic_t nr_switch_events __read_mostly;
336 static LIST_HEAD(pmus);
337 static DEFINE_MUTEX(pmus_lock);
338 static struct srcu_struct pmus_srcu;
341 * perf event paranoia level:
342 * -1 - not paranoid at all
343 * 0 - disallow raw tracepoint access for unpriv
344 * 1 - disallow cpu events for unpriv
345 * 2 - disallow kernel profiling for unpriv
347 int sysctl_perf_event_paranoid __read_mostly = 1;
349 /* Minimum for 512 kiB + 1 user control page */
350 int sysctl_perf_event_mlock __read_mostly = 512 + (PAGE_SIZE / 1024); /* 'free' kiB per user */
353 * max perf event sample rate
355 #define DEFAULT_MAX_SAMPLE_RATE 100000
356 #define DEFAULT_SAMPLE_PERIOD_NS (NSEC_PER_SEC / DEFAULT_MAX_SAMPLE_RATE)
357 #define DEFAULT_CPU_TIME_MAX_PERCENT 25
359 int sysctl_perf_event_sample_rate __read_mostly = DEFAULT_MAX_SAMPLE_RATE;
361 static int max_samples_per_tick __read_mostly = DIV_ROUND_UP(DEFAULT_MAX_SAMPLE_RATE, HZ);
362 static int perf_sample_period_ns __read_mostly = DEFAULT_SAMPLE_PERIOD_NS;
364 static int perf_sample_allowed_ns __read_mostly =
365 DEFAULT_SAMPLE_PERIOD_NS * DEFAULT_CPU_TIME_MAX_PERCENT / 100;
367 static void update_perf_cpu_limits(void)
369 u64 tmp = perf_sample_period_ns;
371 tmp *= sysctl_perf_cpu_time_max_percent;
373 ACCESS_ONCE(perf_sample_allowed_ns) = tmp;
376 static int perf_rotate_context(struct perf_cpu_context *cpuctx);
378 int perf_proc_update_handler(struct ctl_table *table, int write,
379 void __user *buffer, size_t *lenp,
382 int ret = proc_dointvec_minmax(table, write, buffer, lenp, ppos);
387 max_samples_per_tick = DIV_ROUND_UP(sysctl_perf_event_sample_rate, HZ);
388 perf_sample_period_ns = NSEC_PER_SEC / sysctl_perf_event_sample_rate;
389 update_perf_cpu_limits();
394 int sysctl_perf_cpu_time_max_percent __read_mostly = DEFAULT_CPU_TIME_MAX_PERCENT;
396 int perf_cpu_time_max_percent_handler(struct ctl_table *table, int write,
397 void __user *buffer, size_t *lenp,
400 int ret = proc_dointvec(table, write, buffer, lenp, ppos);
405 update_perf_cpu_limits();
411 * perf samples are done in some very critical code paths (NMIs).
412 * If they take too much CPU time, the system can lock up and not
413 * get any real work done. This will drop the sample rate when
414 * we detect that events are taking too long.
416 #define NR_ACCUMULATED_SAMPLES 128
417 static DEFINE_PER_CPU(u64, running_sample_length);
419 static void perf_duration_warn(struct irq_work *w)
421 u64 allowed_ns = ACCESS_ONCE(perf_sample_allowed_ns);
422 u64 avg_local_sample_len;
423 u64 local_samples_len;
425 local_samples_len = __this_cpu_read(running_sample_length);
426 avg_local_sample_len = local_samples_len/NR_ACCUMULATED_SAMPLES;
428 printk_ratelimited(KERN_WARNING
429 "perf interrupt took too long (%lld > %lld), lowering "
430 "kernel.perf_event_max_sample_rate to %d\n",
431 avg_local_sample_len, allowed_ns >> 1,
432 sysctl_perf_event_sample_rate);
435 static DEFINE_IRQ_WORK(perf_duration_work, perf_duration_warn);
437 void perf_sample_event_took(u64 sample_len_ns)
439 u64 allowed_ns = ACCESS_ONCE(perf_sample_allowed_ns);
440 u64 avg_local_sample_len;
441 u64 local_samples_len;
446 /* decay the counter by 1 average sample */
447 local_samples_len = __this_cpu_read(running_sample_length);
448 local_samples_len -= local_samples_len/NR_ACCUMULATED_SAMPLES;
449 local_samples_len += sample_len_ns;
450 __this_cpu_write(running_sample_length, local_samples_len);
453 * note: this will be biased artifically low until we have
454 * seen NR_ACCUMULATED_SAMPLES. Doing it this way keeps us
455 * from having to maintain a count.
457 avg_local_sample_len = local_samples_len/NR_ACCUMULATED_SAMPLES;
459 if (avg_local_sample_len <= allowed_ns)
462 if (max_samples_per_tick <= 1)
465 max_samples_per_tick = DIV_ROUND_UP(max_samples_per_tick, 2);
466 sysctl_perf_event_sample_rate = max_samples_per_tick * HZ;
467 perf_sample_period_ns = NSEC_PER_SEC / sysctl_perf_event_sample_rate;
469 update_perf_cpu_limits();
471 if (!irq_work_queue(&perf_duration_work)) {
472 early_printk("perf interrupt took too long (%lld > %lld), lowering "
473 "kernel.perf_event_max_sample_rate to %d\n",
474 avg_local_sample_len, allowed_ns >> 1,
475 sysctl_perf_event_sample_rate);
479 static atomic64_t perf_event_id;
481 static void cpu_ctx_sched_out(struct perf_cpu_context *cpuctx,
482 enum event_type_t event_type);
484 static void cpu_ctx_sched_in(struct perf_cpu_context *cpuctx,
485 enum event_type_t event_type,
486 struct task_struct *task);
488 static void update_context_time(struct perf_event_context *ctx);
489 static u64 perf_event_time(struct perf_event *event);
491 void __weak perf_event_print_debug(void) { }
493 extern __weak const char *perf_pmu_name(void)
498 static inline u64 perf_clock(void)
500 return local_clock();
503 static inline u64 perf_event_clock(struct perf_event *event)
505 return event->clock();
508 #ifdef CONFIG_CGROUP_PERF
511 perf_cgroup_match(struct perf_event *event)
513 struct perf_event_context *ctx = event->ctx;
514 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
516 /* @event doesn't care about cgroup */
520 /* wants specific cgroup scope but @cpuctx isn't associated with any */
525 * Cgroup scoping is recursive. An event enabled for a cgroup is
526 * also enabled for all its descendant cgroups. If @cpuctx's
527 * cgroup is a descendant of @event's (the test covers identity
528 * case), it's a match.
530 return cgroup_is_descendant(cpuctx->cgrp->css.cgroup,
531 event->cgrp->css.cgroup);
534 static inline void perf_detach_cgroup(struct perf_event *event)
536 css_put(&event->cgrp->css);
540 static inline int is_cgroup_event(struct perf_event *event)
542 return event->cgrp != NULL;
545 static inline u64 perf_cgroup_event_time(struct perf_event *event)
547 struct perf_cgroup_info *t;
549 t = per_cpu_ptr(event->cgrp->info, event->cpu);
553 static inline void __update_cgrp_time(struct perf_cgroup *cgrp)
555 struct perf_cgroup_info *info;
560 info = this_cpu_ptr(cgrp->info);
562 info->time += now - info->timestamp;
563 info->timestamp = now;
566 static inline void update_cgrp_time_from_cpuctx(struct perf_cpu_context *cpuctx)
568 struct perf_cgroup *cgrp_out = cpuctx->cgrp;
570 __update_cgrp_time(cgrp_out);
573 static inline void update_cgrp_time_from_event(struct perf_event *event)
575 struct perf_cgroup *cgrp;
578 * ensure we access cgroup data only when needed and
579 * when we know the cgroup is pinned (css_get)
581 if (!is_cgroup_event(event))
584 cgrp = perf_cgroup_from_task(current, event->ctx);
586 * Do not update time when cgroup is not active
588 if (cgrp == event->cgrp)
589 __update_cgrp_time(event->cgrp);
593 perf_cgroup_set_timestamp(struct task_struct *task,
594 struct perf_event_context *ctx)
596 struct perf_cgroup *cgrp;
597 struct perf_cgroup_info *info;
600 * ctx->lock held by caller
601 * ensure we do not access cgroup data
602 * unless we have the cgroup pinned (css_get)
604 if (!task || !ctx->nr_cgroups)
607 cgrp = perf_cgroup_from_task(task, ctx);
608 info = this_cpu_ptr(cgrp->info);
609 info->timestamp = ctx->timestamp;
612 #define PERF_CGROUP_SWOUT 0x1 /* cgroup switch out every event */
613 #define PERF_CGROUP_SWIN 0x2 /* cgroup switch in events based on task */
616 * reschedule events based on the cgroup constraint of task.
618 * mode SWOUT : schedule out everything
619 * mode SWIN : schedule in based on cgroup for next
621 static void perf_cgroup_switch(struct task_struct *task, int mode)
623 struct perf_cpu_context *cpuctx;
628 * disable interrupts to avoid geting nr_cgroup
629 * changes via __perf_event_disable(). Also
632 local_irq_save(flags);
635 * we reschedule only in the presence of cgroup
636 * constrained events.
639 list_for_each_entry_rcu(pmu, &pmus, entry) {
640 cpuctx = this_cpu_ptr(pmu->pmu_cpu_context);
641 if (cpuctx->unique_pmu != pmu)
642 continue; /* ensure we process each cpuctx once */
645 * perf_cgroup_events says at least one
646 * context on this CPU has cgroup events.
648 * ctx->nr_cgroups reports the number of cgroup
649 * events for a context.
651 if (cpuctx->ctx.nr_cgroups > 0) {
652 perf_ctx_lock(cpuctx, cpuctx->task_ctx);
653 perf_pmu_disable(cpuctx->ctx.pmu);
655 if (mode & PERF_CGROUP_SWOUT) {
656 cpu_ctx_sched_out(cpuctx, EVENT_ALL);
658 * must not be done before ctxswout due
659 * to event_filter_match() in event_sched_out()
664 if (mode & PERF_CGROUP_SWIN) {
665 WARN_ON_ONCE(cpuctx->cgrp);
667 * set cgrp before ctxsw in to allow
668 * event_filter_match() to not have to pass
670 * we pass the cpuctx->ctx to perf_cgroup_from_task()
671 * because cgorup events are only per-cpu
673 cpuctx->cgrp = perf_cgroup_from_task(task, &cpuctx->ctx);
674 cpu_ctx_sched_in(cpuctx, EVENT_ALL, task);
676 perf_pmu_enable(cpuctx->ctx.pmu);
677 perf_ctx_unlock(cpuctx, cpuctx->task_ctx);
681 local_irq_restore(flags);
684 static inline void perf_cgroup_sched_out(struct task_struct *task,
685 struct task_struct *next)
687 struct perf_cgroup *cgrp1;
688 struct perf_cgroup *cgrp2 = NULL;
692 * we come here when we know perf_cgroup_events > 0
693 * we do not need to pass the ctx here because we know
694 * we are holding the rcu lock
696 cgrp1 = perf_cgroup_from_task(task, NULL);
697 cgrp2 = perf_cgroup_from_task(next, NULL);
700 * only schedule out current cgroup events if we know
701 * that we are switching to a different cgroup. Otherwise,
702 * do no touch the cgroup events.
705 perf_cgroup_switch(task, PERF_CGROUP_SWOUT);
710 static inline void perf_cgroup_sched_in(struct task_struct *prev,
711 struct task_struct *task)
713 struct perf_cgroup *cgrp1;
714 struct perf_cgroup *cgrp2 = NULL;
718 * we come here when we know perf_cgroup_events > 0
719 * we do not need to pass the ctx here because we know
720 * we are holding the rcu lock
722 cgrp1 = perf_cgroup_from_task(task, NULL);
723 cgrp2 = perf_cgroup_from_task(prev, NULL);
726 * only need to schedule in cgroup events if we are changing
727 * cgroup during ctxsw. Cgroup events were not scheduled
728 * out of ctxsw out if that was not the case.
731 perf_cgroup_switch(task, PERF_CGROUP_SWIN);
736 static inline int perf_cgroup_connect(int fd, struct perf_event *event,
737 struct perf_event_attr *attr,
738 struct perf_event *group_leader)
740 struct perf_cgroup *cgrp;
741 struct cgroup_subsys_state *css;
742 struct fd f = fdget(fd);
748 css = css_tryget_online_from_dir(f.file->f_path.dentry,
749 &perf_event_cgrp_subsys);
755 cgrp = container_of(css, struct perf_cgroup, css);
759 * all events in a group must monitor
760 * the same cgroup because a task belongs
761 * to only one perf cgroup at a time
763 if (group_leader && group_leader->cgrp != cgrp) {
764 perf_detach_cgroup(event);
773 perf_cgroup_set_shadow_time(struct perf_event *event, u64 now)
775 struct perf_cgroup_info *t;
776 t = per_cpu_ptr(event->cgrp->info, event->cpu);
777 event->shadow_ctx_time = now - t->timestamp;
781 perf_cgroup_defer_enabled(struct perf_event *event)
784 * when the current task's perf cgroup does not match
785 * the event's, we need to remember to call the
786 * perf_mark_enable() function the first time a task with
787 * a matching perf cgroup is scheduled in.
789 if (is_cgroup_event(event) && !perf_cgroup_match(event))
790 event->cgrp_defer_enabled = 1;
794 perf_cgroup_mark_enabled(struct perf_event *event,
795 struct perf_event_context *ctx)
797 struct perf_event *sub;
798 u64 tstamp = perf_event_time(event);
800 if (!event->cgrp_defer_enabled)
803 event->cgrp_defer_enabled = 0;
805 event->tstamp_enabled = tstamp - event->total_time_enabled;
806 list_for_each_entry(sub, &event->sibling_list, group_entry) {
807 if (sub->state >= PERF_EVENT_STATE_INACTIVE) {
808 sub->tstamp_enabled = tstamp - sub->total_time_enabled;
809 sub->cgrp_defer_enabled = 0;
813 #else /* !CONFIG_CGROUP_PERF */
816 perf_cgroup_match(struct perf_event *event)
821 static inline void perf_detach_cgroup(struct perf_event *event)
824 static inline int is_cgroup_event(struct perf_event *event)
829 static inline u64 perf_cgroup_event_cgrp_time(struct perf_event *event)
834 static inline void update_cgrp_time_from_event(struct perf_event *event)
838 static inline void update_cgrp_time_from_cpuctx(struct perf_cpu_context *cpuctx)
842 static inline void perf_cgroup_sched_out(struct task_struct *task,
843 struct task_struct *next)
847 static inline void perf_cgroup_sched_in(struct task_struct *prev,
848 struct task_struct *task)
852 static inline int perf_cgroup_connect(pid_t pid, struct perf_event *event,
853 struct perf_event_attr *attr,
854 struct perf_event *group_leader)
860 perf_cgroup_set_timestamp(struct task_struct *task,
861 struct perf_event_context *ctx)
866 perf_cgroup_switch(struct task_struct *task, struct task_struct *next)
871 perf_cgroup_set_shadow_time(struct perf_event *event, u64 now)
875 static inline u64 perf_cgroup_event_time(struct perf_event *event)
881 perf_cgroup_defer_enabled(struct perf_event *event)
886 perf_cgroup_mark_enabled(struct perf_event *event,
887 struct perf_event_context *ctx)
893 * set default to be dependent on timer tick just
896 #define PERF_CPU_HRTIMER (1000 / HZ)
898 * function must be called with interrupts disbled
900 static enum hrtimer_restart perf_mux_hrtimer_handler(struct hrtimer *hr)
902 struct perf_cpu_context *cpuctx;
905 WARN_ON(!irqs_disabled());
907 cpuctx = container_of(hr, struct perf_cpu_context, hrtimer);
908 rotations = perf_rotate_context(cpuctx);
910 raw_spin_lock(&cpuctx->hrtimer_lock);
912 hrtimer_forward_now(hr, cpuctx->hrtimer_interval);
914 cpuctx->hrtimer_active = 0;
915 raw_spin_unlock(&cpuctx->hrtimer_lock);
917 return rotations ? HRTIMER_RESTART : HRTIMER_NORESTART;
920 static void __perf_mux_hrtimer_init(struct perf_cpu_context *cpuctx, int cpu)
922 struct hrtimer *timer = &cpuctx->hrtimer;
923 struct pmu *pmu = cpuctx->ctx.pmu;
926 /* no multiplexing needed for SW PMU */
927 if (pmu->task_ctx_nr == perf_sw_context)
931 * check default is sane, if not set then force to
932 * default interval (1/tick)
934 interval = pmu->hrtimer_interval_ms;
936 interval = pmu->hrtimer_interval_ms = PERF_CPU_HRTIMER;
938 cpuctx->hrtimer_interval = ns_to_ktime(NSEC_PER_MSEC * interval);
940 raw_spin_lock_init(&cpuctx->hrtimer_lock);
941 hrtimer_init(timer, CLOCK_MONOTONIC, HRTIMER_MODE_ABS_PINNED);
942 timer->function = perf_mux_hrtimer_handler;
945 static int perf_mux_hrtimer_restart(struct perf_cpu_context *cpuctx)
947 struct hrtimer *timer = &cpuctx->hrtimer;
948 struct pmu *pmu = cpuctx->ctx.pmu;
952 if (pmu->task_ctx_nr == perf_sw_context)
955 raw_spin_lock_irqsave(&cpuctx->hrtimer_lock, flags);
956 if (!cpuctx->hrtimer_active) {
957 cpuctx->hrtimer_active = 1;
958 hrtimer_forward_now(timer, cpuctx->hrtimer_interval);
959 hrtimer_start_expires(timer, HRTIMER_MODE_ABS_PINNED);
961 raw_spin_unlock_irqrestore(&cpuctx->hrtimer_lock, flags);
966 void perf_pmu_disable(struct pmu *pmu)
968 int *count = this_cpu_ptr(pmu->pmu_disable_count);
970 pmu->pmu_disable(pmu);
973 void perf_pmu_enable(struct pmu *pmu)
975 int *count = this_cpu_ptr(pmu->pmu_disable_count);
977 pmu->pmu_enable(pmu);
980 static DEFINE_PER_CPU(struct list_head, active_ctx_list);
983 * perf_event_ctx_activate(), perf_event_ctx_deactivate(), and
984 * perf_event_task_tick() are fully serialized because they're strictly cpu
985 * affine and perf_event_ctx{activate,deactivate} are called with IRQs
986 * disabled, while perf_event_task_tick is called from IRQ context.
988 static void perf_event_ctx_activate(struct perf_event_context *ctx)
990 struct list_head *head = this_cpu_ptr(&active_ctx_list);
992 WARN_ON(!irqs_disabled());
994 WARN_ON(!list_empty(&ctx->active_ctx_list));
996 list_add(&ctx->active_ctx_list, head);
999 static void perf_event_ctx_deactivate(struct perf_event_context *ctx)
1001 WARN_ON(!irqs_disabled());
1003 WARN_ON(list_empty(&ctx->active_ctx_list));
1005 list_del_init(&ctx->active_ctx_list);
1008 static void get_ctx(struct perf_event_context *ctx)
1010 WARN_ON(!atomic_inc_not_zero(&ctx->refcount));
1013 static void free_ctx(struct rcu_head *head)
1015 struct perf_event_context *ctx;
1017 ctx = container_of(head, struct perf_event_context, rcu_head);
1018 kfree(ctx->task_ctx_data);
1022 static void put_ctx(struct perf_event_context *ctx)
1024 if (atomic_dec_and_test(&ctx->refcount)) {
1025 if (ctx->parent_ctx)
1026 put_ctx(ctx->parent_ctx);
1027 if (ctx->task && ctx->task != TASK_TOMBSTONE)
1028 put_task_struct(ctx->task);
1029 call_rcu(&ctx->rcu_head, free_ctx);
1034 * Because of perf_event::ctx migration in sys_perf_event_open::move_group and
1035 * perf_pmu_migrate_context() we need some magic.
1037 * Those places that change perf_event::ctx will hold both
1038 * perf_event_ctx::mutex of the 'old' and 'new' ctx value.
1040 * Lock ordering is by mutex address. There are two other sites where
1041 * perf_event_context::mutex nests and those are:
1043 * - perf_event_exit_task_context() [ child , 0 ]
1044 * perf_event_exit_event()
1045 * put_event() [ parent, 1 ]
1047 * - perf_event_init_context() [ parent, 0 ]
1048 * inherit_task_group()
1051 * perf_event_alloc()
1053 * perf_try_init_event() [ child , 1 ]
1055 * While it appears there is an obvious deadlock here -- the parent and child
1056 * nesting levels are inverted between the two. This is in fact safe because
1057 * life-time rules separate them. That is an exiting task cannot fork, and a
1058 * spawning task cannot (yet) exit.
1060 * But remember that that these are parent<->child context relations, and
1061 * migration does not affect children, therefore these two orderings should not
1064 * The change in perf_event::ctx does not affect children (as claimed above)
1065 * because the sys_perf_event_open() case will install a new event and break
1066 * the ctx parent<->child relation, and perf_pmu_migrate_context() is only
1067 * concerned with cpuctx and that doesn't have children.
1069 * The places that change perf_event::ctx will issue:
1071 * perf_remove_from_context();
1072 * synchronize_rcu();
1073 * perf_install_in_context();
1075 * to affect the change. The remove_from_context() + synchronize_rcu() should
1076 * quiesce the event, after which we can install it in the new location. This
1077 * means that only external vectors (perf_fops, prctl) can perturb the event
1078 * while in transit. Therefore all such accessors should also acquire
1079 * perf_event_context::mutex to serialize against this.
1081 * However; because event->ctx can change while we're waiting to acquire
1082 * ctx->mutex we must be careful and use the below perf_event_ctx_lock()
1086 * task_struct::perf_event_mutex
1087 * perf_event_context::mutex
1088 * perf_event::child_mutex;
1089 * perf_event_context::lock
1090 * perf_event::mmap_mutex
1093 static struct perf_event_context *
1094 perf_event_ctx_lock_nested(struct perf_event *event, int nesting)
1096 struct perf_event_context *ctx;
1100 ctx = ACCESS_ONCE(event->ctx);
1101 if (!atomic_inc_not_zero(&ctx->refcount)) {
1107 mutex_lock_nested(&ctx->mutex, nesting);
1108 if (event->ctx != ctx) {
1109 mutex_unlock(&ctx->mutex);
1117 static inline struct perf_event_context *
1118 perf_event_ctx_lock(struct perf_event *event)
1120 return perf_event_ctx_lock_nested(event, 0);
1123 static void perf_event_ctx_unlock(struct perf_event *event,
1124 struct perf_event_context *ctx)
1126 mutex_unlock(&ctx->mutex);
1131 * This must be done under the ctx->lock, such as to serialize against
1132 * context_equiv(), therefore we cannot call put_ctx() since that might end up
1133 * calling scheduler related locks and ctx->lock nests inside those.
1135 static __must_check struct perf_event_context *
1136 unclone_ctx(struct perf_event_context *ctx)
1138 struct perf_event_context *parent_ctx = ctx->parent_ctx;
1140 lockdep_assert_held(&ctx->lock);
1143 ctx->parent_ctx = NULL;
1149 static u32 perf_event_pid(struct perf_event *event, struct task_struct *p)
1152 * only top level events have the pid namespace they were created in
1155 event = event->parent;
1157 return task_tgid_nr_ns(p, event->ns);
1160 static u32 perf_event_tid(struct perf_event *event, struct task_struct *p)
1163 * only top level events have the pid namespace they were created in
1166 event = event->parent;
1168 return task_pid_nr_ns(p, event->ns);
1172 * If we inherit events we want to return the parent event id
1175 static u64 primary_event_id(struct perf_event *event)
1180 id = event->parent->id;
1186 * Get the perf_event_context for a task and lock it.
1188 * This has to cope with with the fact that until it is locked,
1189 * the context could get moved to another task.
1191 static struct perf_event_context *
1192 perf_lock_task_context(struct task_struct *task, int ctxn, unsigned long *flags)
1194 struct perf_event_context *ctx;
1198 * One of the few rules of preemptible RCU is that one cannot do
1199 * rcu_read_unlock() while holding a scheduler (or nested) lock when
1200 * part of the read side critical section was irqs-enabled -- see
1201 * rcu_read_unlock_special().
1203 * Since ctx->lock nests under rq->lock we must ensure the entire read
1204 * side critical section has interrupts disabled.
1206 local_irq_save(*flags);
1208 ctx = rcu_dereference(task->perf_event_ctxp[ctxn]);
1211 * If this context is a clone of another, it might
1212 * get swapped for another underneath us by
1213 * perf_event_task_sched_out, though the
1214 * rcu_read_lock() protects us from any context
1215 * getting freed. Lock the context and check if it
1216 * got swapped before we could get the lock, and retry
1217 * if so. If we locked the right context, then it
1218 * can't get swapped on us any more.
1220 raw_spin_lock(&ctx->lock);
1221 if (ctx != rcu_dereference(task->perf_event_ctxp[ctxn])) {
1222 raw_spin_unlock(&ctx->lock);
1224 local_irq_restore(*flags);
1228 if (ctx->task == TASK_TOMBSTONE ||
1229 !atomic_inc_not_zero(&ctx->refcount)) {
1230 raw_spin_unlock(&ctx->lock);
1233 WARN_ON_ONCE(ctx->task != task);
1238 local_irq_restore(*flags);
1243 * Get the context for a task and increment its pin_count so it
1244 * can't get swapped to another task. This also increments its
1245 * reference count so that the context can't get freed.
1247 static struct perf_event_context *
1248 perf_pin_task_context(struct task_struct *task, int ctxn)
1250 struct perf_event_context *ctx;
1251 unsigned long flags;
1253 ctx = perf_lock_task_context(task, ctxn, &flags);
1256 raw_spin_unlock_irqrestore(&ctx->lock, flags);
1261 static void perf_unpin_context(struct perf_event_context *ctx)
1263 unsigned long flags;
1265 raw_spin_lock_irqsave(&ctx->lock, flags);
1267 raw_spin_unlock_irqrestore(&ctx->lock, flags);
1271 * Update the record of the current time in a context.
1273 static void update_context_time(struct perf_event_context *ctx)
1275 u64 now = perf_clock();
1277 ctx->time += now - ctx->timestamp;
1278 ctx->timestamp = now;
1281 static u64 perf_event_time(struct perf_event *event)
1283 struct perf_event_context *ctx = event->ctx;
1285 if (is_cgroup_event(event))
1286 return perf_cgroup_event_time(event);
1288 return ctx ? ctx->time : 0;
1292 * Update the total_time_enabled and total_time_running fields for a event.
1293 * The caller of this function needs to hold the ctx->lock.
1295 static void update_event_times(struct perf_event *event)
1297 struct perf_event_context *ctx = event->ctx;
1300 if (event->state < PERF_EVENT_STATE_INACTIVE ||
1301 event->group_leader->state < PERF_EVENT_STATE_INACTIVE)
1304 * in cgroup mode, time_enabled represents
1305 * the time the event was enabled AND active
1306 * tasks were in the monitored cgroup. This is
1307 * independent of the activity of the context as
1308 * there may be a mix of cgroup and non-cgroup events.
1310 * That is why we treat cgroup events differently
1313 if (is_cgroup_event(event))
1314 run_end = perf_cgroup_event_time(event);
1315 else if (ctx->is_active)
1316 run_end = ctx->time;
1318 run_end = event->tstamp_stopped;
1320 event->total_time_enabled = run_end - event->tstamp_enabled;
1322 if (event->state == PERF_EVENT_STATE_INACTIVE)
1323 run_end = event->tstamp_stopped;
1325 run_end = perf_event_time(event);
1327 event->total_time_running = run_end - event->tstamp_running;
1332 * Update total_time_enabled and total_time_running for all events in a group.
1334 static void update_group_times(struct perf_event *leader)
1336 struct perf_event *event;
1338 update_event_times(leader);
1339 list_for_each_entry(event, &leader->sibling_list, group_entry)
1340 update_event_times(event);
1343 static struct list_head *
1344 ctx_group_list(struct perf_event *event, struct perf_event_context *ctx)
1346 if (event->attr.pinned)
1347 return &ctx->pinned_groups;
1349 return &ctx->flexible_groups;
1353 * Add a event from the lists for its context.
1354 * Must be called with ctx->mutex and ctx->lock held.
1357 list_add_event(struct perf_event *event, struct perf_event_context *ctx)
1359 lockdep_assert_held(&ctx->lock);
1361 WARN_ON_ONCE(event->attach_state & PERF_ATTACH_CONTEXT);
1362 event->attach_state |= PERF_ATTACH_CONTEXT;
1365 * If we're a stand alone event or group leader, we go to the context
1366 * list, group events are kept attached to the group so that
1367 * perf_group_detach can, at all times, locate all siblings.
1369 if (event->group_leader == event) {
1370 struct list_head *list;
1372 if (is_software_event(event))
1373 event->group_flags |= PERF_GROUP_SOFTWARE;
1375 list = ctx_group_list(event, ctx);
1376 list_add_tail(&event->group_entry, list);
1379 if (is_cgroup_event(event))
1382 list_add_rcu(&event->event_entry, &ctx->event_list);
1384 if (event->attr.inherit_stat)
1391 * Initialize event state based on the perf_event_attr::disabled.
1393 static inline void perf_event__state_init(struct perf_event *event)
1395 event->state = event->attr.disabled ? PERF_EVENT_STATE_OFF :
1396 PERF_EVENT_STATE_INACTIVE;
1399 static void __perf_event_read_size(struct perf_event *event, int nr_siblings)
1401 int entry = sizeof(u64); /* value */
1405 if (event->attr.read_format & PERF_FORMAT_TOTAL_TIME_ENABLED)
1406 size += sizeof(u64);
1408 if (event->attr.read_format & PERF_FORMAT_TOTAL_TIME_RUNNING)
1409 size += sizeof(u64);
1411 if (event->attr.read_format & PERF_FORMAT_ID)
1412 entry += sizeof(u64);
1414 if (event->attr.read_format & PERF_FORMAT_GROUP) {
1416 size += sizeof(u64);
1420 event->read_size = size;
1423 static void __perf_event_header_size(struct perf_event *event, u64 sample_type)
1425 struct perf_sample_data *data;
1428 if (sample_type & PERF_SAMPLE_IP)
1429 size += sizeof(data->ip);
1431 if (sample_type & PERF_SAMPLE_ADDR)
1432 size += sizeof(data->addr);
1434 if (sample_type & PERF_SAMPLE_PERIOD)
1435 size += sizeof(data->period);
1437 if (sample_type & PERF_SAMPLE_WEIGHT)
1438 size += sizeof(data->weight);
1440 if (sample_type & PERF_SAMPLE_READ)
1441 size += event->read_size;
1443 if (sample_type & PERF_SAMPLE_DATA_SRC)
1444 size += sizeof(data->data_src.val);
1446 if (sample_type & PERF_SAMPLE_TRANSACTION)
1447 size += sizeof(data->txn);
1449 event->header_size = size;
1453 * Called at perf_event creation and when events are attached/detached from a
1456 static void perf_event__header_size(struct perf_event *event)
1458 __perf_event_read_size(event,
1459 event->group_leader->nr_siblings);
1460 __perf_event_header_size(event, event->attr.sample_type);
1463 static void perf_event__id_header_size(struct perf_event *event)
1465 struct perf_sample_data *data;
1466 u64 sample_type = event->attr.sample_type;
1469 if (sample_type & PERF_SAMPLE_TID)
1470 size += sizeof(data->tid_entry);
1472 if (sample_type & PERF_SAMPLE_TIME)
1473 size += sizeof(data->time);
1475 if (sample_type & PERF_SAMPLE_IDENTIFIER)
1476 size += sizeof(data->id);
1478 if (sample_type & PERF_SAMPLE_ID)
1479 size += sizeof(data->id);
1481 if (sample_type & PERF_SAMPLE_STREAM_ID)
1482 size += sizeof(data->stream_id);
1484 if (sample_type & PERF_SAMPLE_CPU)
1485 size += sizeof(data->cpu_entry);
1487 event->id_header_size = size;
1490 static bool perf_event_validate_size(struct perf_event *event)
1493 * The values computed here will be over-written when we actually
1496 __perf_event_read_size(event, event->group_leader->nr_siblings + 1);
1497 __perf_event_header_size(event, event->attr.sample_type & ~PERF_SAMPLE_READ);
1498 perf_event__id_header_size(event);
1501 * Sum the lot; should not exceed the 64k limit we have on records.
1502 * Conservative limit to allow for callchains and other variable fields.
1504 if (event->read_size + event->header_size +
1505 event->id_header_size + sizeof(struct perf_event_header) >= 16*1024)
1511 static void perf_group_attach(struct perf_event *event)
1513 struct perf_event *group_leader = event->group_leader, *pos;
1516 * We can have double attach due to group movement in perf_event_open.
1518 if (event->attach_state & PERF_ATTACH_GROUP)
1521 event->attach_state |= PERF_ATTACH_GROUP;
1523 if (group_leader == event)
1526 WARN_ON_ONCE(group_leader->ctx != event->ctx);
1528 if (group_leader->group_flags & PERF_GROUP_SOFTWARE &&
1529 !is_software_event(event))
1530 group_leader->group_flags &= ~PERF_GROUP_SOFTWARE;
1532 list_add_tail(&event->group_entry, &group_leader->sibling_list);
1533 group_leader->nr_siblings++;
1535 perf_event__header_size(group_leader);
1537 list_for_each_entry(pos, &group_leader->sibling_list, group_entry)
1538 perf_event__header_size(pos);
1542 * Remove a event from the lists for its context.
1543 * Must be called with ctx->mutex and ctx->lock held.
1546 list_del_event(struct perf_event *event, struct perf_event_context *ctx)
1548 struct perf_cpu_context *cpuctx;
1550 WARN_ON_ONCE(event->ctx != ctx);
1551 lockdep_assert_held(&ctx->lock);
1554 * We can have double detach due to exit/hot-unplug + close.
1556 if (!(event->attach_state & PERF_ATTACH_CONTEXT))
1559 event->attach_state &= ~PERF_ATTACH_CONTEXT;
1561 if (is_cgroup_event(event)) {
1564 * Because cgroup events are always per-cpu events, this will
1565 * always be called from the right CPU.
1567 cpuctx = __get_cpu_context(ctx);
1569 * If there are no more cgroup events then clear cgrp to avoid
1570 * stale pointer in update_cgrp_time_from_cpuctx().
1572 if (!ctx->nr_cgroups)
1573 cpuctx->cgrp = NULL;
1577 if (event->attr.inherit_stat)
1580 list_del_rcu(&event->event_entry);
1582 if (event->group_leader == event)
1583 list_del_init(&event->group_entry);
1585 update_group_times(event);
1588 * If event was in error state, then keep it
1589 * that way, otherwise bogus counts will be
1590 * returned on read(). The only way to get out
1591 * of error state is by explicit re-enabling
1594 if (event->state > PERF_EVENT_STATE_OFF)
1595 event->state = PERF_EVENT_STATE_OFF;
1600 static void perf_group_detach(struct perf_event *event)
1602 struct perf_event *sibling, *tmp;
1603 struct list_head *list = NULL;
1606 * We can have double detach due to exit/hot-unplug + close.
1608 if (!(event->attach_state & PERF_ATTACH_GROUP))
1611 event->attach_state &= ~PERF_ATTACH_GROUP;
1614 * If this is a sibling, remove it from its group.
1616 if (event->group_leader != event) {
1617 list_del_init(&event->group_entry);
1618 event->group_leader->nr_siblings--;
1622 if (!list_empty(&event->group_entry))
1623 list = &event->group_entry;
1626 * If this was a group event with sibling events then
1627 * upgrade the siblings to singleton events by adding them
1628 * to whatever list we are on.
1630 list_for_each_entry_safe(sibling, tmp, &event->sibling_list, group_entry) {
1632 list_move_tail(&sibling->group_entry, list);
1633 sibling->group_leader = sibling;
1635 /* Inherit group flags from the previous leader */
1636 sibling->group_flags = event->group_flags;
1638 WARN_ON_ONCE(sibling->ctx != event->ctx);
1642 perf_event__header_size(event->group_leader);
1644 list_for_each_entry(tmp, &event->group_leader->sibling_list, group_entry)
1645 perf_event__header_size(tmp);
1649 * User event without the task.
1651 static bool is_orphaned_event(struct perf_event *event)
1653 return event && !is_kernel_event(event) && !READ_ONCE(event->owner);
1657 * Event has a parent but parent's task finished and it's
1658 * alive only because of children holding refference.
1660 static bool is_orphaned_child(struct perf_event *event)
1662 return is_orphaned_event(event->parent);
1665 static void orphans_remove_work(struct work_struct *work);
1667 static void schedule_orphans_remove(struct perf_event_context *ctx)
1669 if (!ctx->task || ctx->orphans_remove_sched || !perf_wq)
1672 if (queue_delayed_work(perf_wq, &ctx->orphans_remove, 1)) {
1674 ctx->orphans_remove_sched = true;
1678 static int __init perf_workqueue_init(void)
1680 perf_wq = create_singlethread_workqueue("perf");
1681 WARN(!perf_wq, "failed to create perf workqueue\n");
1682 return perf_wq ? 0 : -1;
1685 core_initcall(perf_workqueue_init);
1687 static inline int pmu_filter_match(struct perf_event *event)
1689 struct pmu *pmu = event->pmu;
1690 return pmu->filter_match ? pmu->filter_match(event) : 1;
1694 event_filter_match(struct perf_event *event)
1696 return (event->cpu == -1 || event->cpu == smp_processor_id())
1697 && perf_cgroup_match(event) && pmu_filter_match(event);
1701 event_sched_out(struct perf_event *event,
1702 struct perf_cpu_context *cpuctx,
1703 struct perf_event_context *ctx)
1705 u64 tstamp = perf_event_time(event);
1708 WARN_ON_ONCE(event->ctx != ctx);
1709 lockdep_assert_held(&ctx->lock);
1712 * An event which could not be activated because of
1713 * filter mismatch still needs to have its timings
1714 * maintained, otherwise bogus information is return
1715 * via read() for time_enabled, time_running:
1717 if (event->state == PERF_EVENT_STATE_INACTIVE
1718 && !event_filter_match(event)) {
1719 delta = tstamp - event->tstamp_stopped;
1720 event->tstamp_running += delta;
1721 event->tstamp_stopped = tstamp;
1724 if (event->state != PERF_EVENT_STATE_ACTIVE)
1727 perf_pmu_disable(event->pmu);
1729 event->state = PERF_EVENT_STATE_INACTIVE;
1730 if (event->pending_disable) {
1731 event->pending_disable = 0;
1732 event->state = PERF_EVENT_STATE_OFF;
1734 event->tstamp_stopped = tstamp;
1735 event->pmu->del(event, 0);
1738 if (!is_software_event(event))
1739 cpuctx->active_oncpu--;
1740 if (!--ctx->nr_active)
1741 perf_event_ctx_deactivate(ctx);
1742 if (event->attr.freq && event->attr.sample_freq)
1744 if (event->attr.exclusive || !cpuctx->active_oncpu)
1745 cpuctx->exclusive = 0;
1747 if (is_orphaned_child(event))
1748 schedule_orphans_remove(ctx);
1750 perf_pmu_enable(event->pmu);
1754 group_sched_out(struct perf_event *group_event,
1755 struct perf_cpu_context *cpuctx,
1756 struct perf_event_context *ctx)
1758 struct perf_event *event;
1759 int state = group_event->state;
1761 event_sched_out(group_event, cpuctx, ctx);
1764 * Schedule out siblings (if any):
1766 list_for_each_entry(event, &group_event->sibling_list, group_entry)
1767 event_sched_out(event, cpuctx, ctx);
1769 if (state == PERF_EVENT_STATE_ACTIVE && group_event->attr.exclusive)
1770 cpuctx->exclusive = 0;
1773 #define DETACH_GROUP 0x01UL
1776 * Cross CPU call to remove a performance event
1778 * We disable the event on the hardware level first. After that we
1779 * remove it from the context list.
1782 __perf_remove_from_context(struct perf_event *event,
1783 struct perf_cpu_context *cpuctx,
1784 struct perf_event_context *ctx,
1787 unsigned long flags = (unsigned long)info;
1789 event_sched_out(event, cpuctx, ctx);
1790 if (flags & DETACH_GROUP)
1791 perf_group_detach(event);
1792 list_del_event(event, ctx);
1794 if (!ctx->nr_events && ctx->is_active) {
1797 WARN_ON_ONCE(cpuctx->task_ctx != ctx);
1798 cpuctx->task_ctx = NULL;
1804 * Remove the event from a task's (or a CPU's) list of events.
1806 * If event->ctx is a cloned context, callers must make sure that
1807 * every task struct that event->ctx->task could possibly point to
1808 * remains valid. This is OK when called from perf_release since
1809 * that only calls us on the top-level context, which can't be a clone.
1810 * When called from perf_event_exit_task, it's OK because the
1811 * context has been detached from its task.
1813 static void perf_remove_from_context(struct perf_event *event, unsigned long flags)
1815 lockdep_assert_held(&event->ctx->mutex);
1817 event_function_call(event, __perf_remove_from_context, (void *)flags);
1821 * Cross CPU call to disable a performance event
1823 static void __perf_event_disable(struct perf_event *event,
1824 struct perf_cpu_context *cpuctx,
1825 struct perf_event_context *ctx,
1828 if (event->state < PERF_EVENT_STATE_INACTIVE)
1831 update_context_time(ctx);
1832 update_cgrp_time_from_event(event);
1833 update_group_times(event);
1834 if (event == event->group_leader)
1835 group_sched_out(event, cpuctx, ctx);
1837 event_sched_out(event, cpuctx, ctx);
1838 event->state = PERF_EVENT_STATE_OFF;
1844 * If event->ctx is a cloned context, callers must make sure that
1845 * every task struct that event->ctx->task could possibly point to
1846 * remains valid. This condition is satisifed when called through
1847 * perf_event_for_each_child or perf_event_for_each because they
1848 * hold the top-level event's child_mutex, so any descendant that
1849 * goes to exit will block in perf_event_exit_event().
1851 * When called from perf_pending_event it's OK because event->ctx
1852 * is the current context on this CPU and preemption is disabled,
1853 * hence we can't get into perf_event_task_sched_out for this context.
1855 static void _perf_event_disable(struct perf_event *event)
1857 struct perf_event_context *ctx = event->ctx;
1859 raw_spin_lock_irq(&ctx->lock);
1860 if (event->state <= PERF_EVENT_STATE_OFF) {
1861 raw_spin_unlock_irq(&ctx->lock);
1864 raw_spin_unlock_irq(&ctx->lock);
1866 event_function_call(event, __perf_event_disable, NULL);
1869 void perf_event_disable_local(struct perf_event *event)
1871 event_function_local(event, __perf_event_disable, NULL);
1875 * Strictly speaking kernel users cannot create groups and therefore this
1876 * interface does not need the perf_event_ctx_lock() magic.
1878 void perf_event_disable(struct perf_event *event)
1880 struct perf_event_context *ctx;
1882 ctx = perf_event_ctx_lock(event);
1883 _perf_event_disable(event);
1884 perf_event_ctx_unlock(event, ctx);
1886 EXPORT_SYMBOL_GPL(perf_event_disable);
1888 static void perf_set_shadow_time(struct perf_event *event,
1889 struct perf_event_context *ctx,
1893 * use the correct time source for the time snapshot
1895 * We could get by without this by leveraging the
1896 * fact that to get to this function, the caller
1897 * has most likely already called update_context_time()
1898 * and update_cgrp_time_xx() and thus both timestamp
1899 * are identical (or very close). Given that tstamp is,
1900 * already adjusted for cgroup, we could say that:
1901 * tstamp - ctx->timestamp
1903 * tstamp - cgrp->timestamp.
1905 * Then, in perf_output_read(), the calculation would
1906 * work with no changes because:
1907 * - event is guaranteed scheduled in
1908 * - no scheduled out in between
1909 * - thus the timestamp would be the same
1911 * But this is a bit hairy.
1913 * So instead, we have an explicit cgroup call to remain
1914 * within the time time source all along. We believe it
1915 * is cleaner and simpler to understand.
1917 if (is_cgroup_event(event))
1918 perf_cgroup_set_shadow_time(event, tstamp);
1920 event->shadow_ctx_time = tstamp - ctx->timestamp;
1923 #define MAX_INTERRUPTS (~0ULL)
1925 static void perf_log_throttle(struct perf_event *event, int enable);
1926 static void perf_log_itrace_start(struct perf_event *event);
1929 event_sched_in(struct perf_event *event,
1930 struct perf_cpu_context *cpuctx,
1931 struct perf_event_context *ctx)
1933 u64 tstamp = perf_event_time(event);
1936 lockdep_assert_held(&ctx->lock);
1938 if (event->state <= PERF_EVENT_STATE_OFF)
1941 event->state = PERF_EVENT_STATE_ACTIVE;
1942 event->oncpu = smp_processor_id();
1945 * Unthrottle events, since we scheduled we might have missed several
1946 * ticks already, also for a heavily scheduling task there is little
1947 * guarantee it'll get a tick in a timely manner.
1949 if (unlikely(event->hw.interrupts == MAX_INTERRUPTS)) {
1950 perf_log_throttle(event, 1);
1951 event->hw.interrupts = 0;
1955 * The new state must be visible before we turn it on in the hardware:
1959 perf_pmu_disable(event->pmu);
1961 perf_set_shadow_time(event, ctx, tstamp);
1963 perf_log_itrace_start(event);
1965 if (event->pmu->add(event, PERF_EF_START)) {
1966 event->state = PERF_EVENT_STATE_INACTIVE;
1972 event->tstamp_running += tstamp - event->tstamp_stopped;
1974 if (!is_software_event(event))
1975 cpuctx->active_oncpu++;
1976 if (!ctx->nr_active++)
1977 perf_event_ctx_activate(ctx);
1978 if (event->attr.freq && event->attr.sample_freq)
1981 if (event->attr.exclusive)
1982 cpuctx->exclusive = 1;
1984 if (is_orphaned_child(event))
1985 schedule_orphans_remove(ctx);
1988 perf_pmu_enable(event->pmu);
1994 group_sched_in(struct perf_event *group_event,
1995 struct perf_cpu_context *cpuctx,
1996 struct perf_event_context *ctx)
1998 struct perf_event *event, *partial_group = NULL;
1999 struct pmu *pmu = ctx->pmu;
2000 u64 now = ctx->time;
2001 bool simulate = false;
2003 if (group_event->state == PERF_EVENT_STATE_OFF)
2006 pmu->start_txn(pmu, PERF_PMU_TXN_ADD);
2008 if (event_sched_in(group_event, cpuctx, ctx)) {
2009 pmu->cancel_txn(pmu);
2010 perf_mux_hrtimer_restart(cpuctx);
2015 * Schedule in siblings as one group (if any):
2017 list_for_each_entry(event, &group_event->sibling_list, group_entry) {
2018 if (event_sched_in(event, cpuctx, ctx)) {
2019 partial_group = event;
2024 if (!pmu->commit_txn(pmu))
2029 * Groups can be scheduled in as one unit only, so undo any
2030 * partial group before returning:
2031 * The events up to the failed event are scheduled out normally,
2032 * tstamp_stopped will be updated.
2034 * The failed events and the remaining siblings need to have
2035 * their timings updated as if they had gone thru event_sched_in()
2036 * and event_sched_out(). This is required to get consistent timings
2037 * across the group. This also takes care of the case where the group
2038 * could never be scheduled by ensuring tstamp_stopped is set to mark
2039 * the time the event was actually stopped, such that time delta
2040 * calculation in update_event_times() is correct.
2042 list_for_each_entry(event, &group_event->sibling_list, group_entry) {
2043 if (event == partial_group)
2047 event->tstamp_running += now - event->tstamp_stopped;
2048 event->tstamp_stopped = now;
2050 event_sched_out(event, cpuctx, ctx);
2053 event_sched_out(group_event, cpuctx, ctx);
2055 pmu->cancel_txn(pmu);
2057 perf_mux_hrtimer_restart(cpuctx);
2063 * Work out whether we can put this event group on the CPU now.
2065 static int group_can_go_on(struct perf_event *event,
2066 struct perf_cpu_context *cpuctx,
2070 * Groups consisting entirely of software events can always go on.
2072 if (event->group_flags & PERF_GROUP_SOFTWARE)
2075 * If an exclusive group is already on, no other hardware
2078 if (cpuctx->exclusive)
2081 * If this group is exclusive and there are already
2082 * events on the CPU, it can't go on.
2084 if (event->attr.exclusive && cpuctx->active_oncpu)
2087 * Otherwise, try to add it if all previous groups were able
2093 static void add_event_to_ctx(struct perf_event *event,
2094 struct perf_event_context *ctx)
2096 u64 tstamp = perf_event_time(event);
2098 list_add_event(event, ctx);
2099 perf_group_attach(event);
2100 event->tstamp_enabled = tstamp;
2101 event->tstamp_running = tstamp;
2102 event->tstamp_stopped = tstamp;
2105 static void task_ctx_sched_out(struct perf_cpu_context *cpuctx,
2106 struct perf_event_context *ctx);
2108 ctx_sched_in(struct perf_event_context *ctx,
2109 struct perf_cpu_context *cpuctx,
2110 enum event_type_t event_type,
2111 struct task_struct *task);
2113 static void perf_event_sched_in(struct perf_cpu_context *cpuctx,
2114 struct perf_event_context *ctx,
2115 struct task_struct *task)
2117 cpu_ctx_sched_in(cpuctx, EVENT_PINNED, task);
2119 ctx_sched_in(ctx, cpuctx, EVENT_PINNED, task);
2120 cpu_ctx_sched_in(cpuctx, EVENT_FLEXIBLE, task);
2122 ctx_sched_in(ctx, cpuctx, EVENT_FLEXIBLE, task);
2125 static void ctx_resched(struct perf_cpu_context *cpuctx,
2126 struct perf_event_context *task_ctx)
2128 perf_pmu_disable(cpuctx->ctx.pmu);
2130 task_ctx_sched_out(cpuctx, task_ctx);
2131 cpu_ctx_sched_out(cpuctx, EVENT_ALL);
2132 perf_event_sched_in(cpuctx, task_ctx, current);
2133 perf_pmu_enable(cpuctx->ctx.pmu);
2137 * Cross CPU call to install and enable a performance event
2139 * Must be called with ctx->mutex held
2141 static int __perf_install_in_context(void *info)
2143 struct perf_event_context *ctx = info;
2144 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
2145 struct perf_event_context *task_ctx = cpuctx->task_ctx;
2147 raw_spin_lock(&cpuctx->ctx.lock);
2149 raw_spin_lock(&ctx->lock);
2151 * If we hit the 'wrong' task, we've since scheduled and
2152 * everything should be sorted, nothing to do!
2155 if (ctx->task != current)
2159 * If task_ctx is set, it had better be to us.
2161 WARN_ON_ONCE(cpuctx->task_ctx != ctx && cpuctx->task_ctx);
2162 } else if (task_ctx) {
2163 raw_spin_lock(&task_ctx->lock);
2166 ctx_resched(cpuctx, task_ctx);
2168 perf_ctx_unlock(cpuctx, task_ctx);
2174 * Attach a performance event to a context
2177 perf_install_in_context(struct perf_event_context *ctx,
2178 struct perf_event *event,
2181 struct task_struct *task = NULL;
2183 lockdep_assert_held(&ctx->mutex);
2186 if (event->cpu != -1)
2190 * Installing events is tricky because we cannot rely on ctx->is_active
2191 * to be set in case this is the nr_events 0 -> 1 transition.
2193 * So what we do is we add the event to the list here, which will allow
2194 * a future context switch to DTRT and then send a racy IPI. If the IPI
2195 * fails to hit the right task, this means a context switch must have
2196 * happened and that will have taken care of business.
2198 raw_spin_lock_irq(&ctx->lock);
2201 * Worse, we cannot even rely on the ctx actually existing anymore. If
2202 * between find_get_context() and perf_install_in_context() the task
2203 * went through perf_event_exit_task() its dead and we should not be
2204 * adding new events.
2206 if (task == TASK_TOMBSTONE) {
2207 raw_spin_unlock_irq(&ctx->lock);
2210 update_context_time(ctx);
2212 * Update cgrp time only if current cgrp matches event->cgrp.
2213 * Must be done before calling add_event_to_ctx().
2215 update_cgrp_time_from_event(event);
2216 add_event_to_ctx(event, ctx);
2217 raw_spin_unlock_irq(&ctx->lock);
2220 task_function_call(task, __perf_install_in_context, ctx);
2222 cpu_function_call(cpu, __perf_install_in_context, ctx);
2226 * Put a event into inactive state and update time fields.
2227 * Enabling the leader of a group effectively enables all
2228 * the group members that aren't explicitly disabled, so we
2229 * have to update their ->tstamp_enabled also.
2230 * Note: this works for group members as well as group leaders
2231 * since the non-leader members' sibling_lists will be empty.
2233 static void __perf_event_mark_enabled(struct perf_event *event)
2235 struct perf_event *sub;
2236 u64 tstamp = perf_event_time(event);
2238 event->state = PERF_EVENT_STATE_INACTIVE;
2239 event->tstamp_enabled = tstamp - event->total_time_enabled;
2240 list_for_each_entry(sub, &event->sibling_list, group_entry) {
2241 if (sub->state >= PERF_EVENT_STATE_INACTIVE)
2242 sub->tstamp_enabled = tstamp - sub->total_time_enabled;
2247 * Cross CPU call to enable a performance event
2249 static void __perf_event_enable(struct perf_event *event,
2250 struct perf_cpu_context *cpuctx,
2251 struct perf_event_context *ctx,
2254 struct perf_event *leader = event->group_leader;
2255 struct perf_event_context *task_ctx;
2257 if (event->state >= PERF_EVENT_STATE_INACTIVE ||
2258 event->state <= PERF_EVENT_STATE_ERROR)
2261 update_context_time(ctx);
2262 __perf_event_mark_enabled(event);
2264 if (!ctx->is_active)
2267 if (!event_filter_match(event)) {
2268 if (is_cgroup_event(event)) {
2269 perf_cgroup_set_timestamp(current, ctx); // XXX ?
2270 perf_cgroup_defer_enabled(event);
2276 * If the event is in a group and isn't the group leader,
2277 * then don't put it on unless the group is on.
2279 if (leader != event && leader->state != PERF_EVENT_STATE_ACTIVE)
2282 task_ctx = cpuctx->task_ctx;
2284 WARN_ON_ONCE(task_ctx != ctx);
2286 ctx_resched(cpuctx, task_ctx);
2292 * If event->ctx is a cloned context, callers must make sure that
2293 * every task struct that event->ctx->task could possibly point to
2294 * remains valid. This condition is satisfied when called through
2295 * perf_event_for_each_child or perf_event_for_each as described
2296 * for perf_event_disable.
2298 static void _perf_event_enable(struct perf_event *event)
2300 struct perf_event_context *ctx = event->ctx;
2302 raw_spin_lock_irq(&ctx->lock);
2303 if (event->state >= PERF_EVENT_STATE_INACTIVE ||
2304 event->state < PERF_EVENT_STATE_ERROR) {
2305 raw_spin_unlock_irq(&ctx->lock);
2310 * If the event is in error state, clear that first.
2312 * That way, if we see the event in error state below, we know that it
2313 * has gone back into error state, as distinct from the task having
2314 * been scheduled away before the cross-call arrived.
2316 if (event->state == PERF_EVENT_STATE_ERROR)
2317 event->state = PERF_EVENT_STATE_OFF;
2318 raw_spin_unlock_irq(&ctx->lock);
2320 event_function_call(event, __perf_event_enable, NULL);
2324 * See perf_event_disable();
2326 void perf_event_enable(struct perf_event *event)
2328 struct perf_event_context *ctx;
2330 ctx = perf_event_ctx_lock(event);
2331 _perf_event_enable(event);
2332 perf_event_ctx_unlock(event, ctx);
2334 EXPORT_SYMBOL_GPL(perf_event_enable);
2336 static int _perf_event_refresh(struct perf_event *event, int refresh)
2339 * not supported on inherited events
2341 if (event->attr.inherit || !is_sampling_event(event))
2344 atomic_add(refresh, &event->event_limit);
2345 _perf_event_enable(event);
2351 * See perf_event_disable()
2353 int perf_event_refresh(struct perf_event *event, int refresh)
2355 struct perf_event_context *ctx;
2358 ctx = perf_event_ctx_lock(event);
2359 ret = _perf_event_refresh(event, refresh);
2360 perf_event_ctx_unlock(event, ctx);
2364 EXPORT_SYMBOL_GPL(perf_event_refresh);
2366 static void ctx_sched_out(struct perf_event_context *ctx,
2367 struct perf_cpu_context *cpuctx,
2368 enum event_type_t event_type)
2370 int is_active = ctx->is_active;
2371 struct perf_event *event;
2373 lockdep_assert_held(&ctx->lock);
2375 if (likely(!ctx->nr_events)) {
2377 * See __perf_remove_from_context().
2379 WARN_ON_ONCE(ctx->is_active);
2381 WARN_ON_ONCE(cpuctx->task_ctx);
2385 ctx->is_active &= ~event_type;
2387 WARN_ON_ONCE(cpuctx->task_ctx != ctx);
2388 if (!ctx->is_active)
2389 cpuctx->task_ctx = NULL;
2392 update_context_time(ctx);
2393 update_cgrp_time_from_cpuctx(cpuctx);
2394 if (!ctx->nr_active)
2397 perf_pmu_disable(ctx->pmu);
2398 if ((is_active & EVENT_PINNED) && (event_type & EVENT_PINNED)) {
2399 list_for_each_entry(event, &ctx->pinned_groups, group_entry)
2400 group_sched_out(event, cpuctx, ctx);
2403 if ((is_active & EVENT_FLEXIBLE) && (event_type & EVENT_FLEXIBLE)) {
2404 list_for_each_entry(event, &ctx->flexible_groups, group_entry)
2405 group_sched_out(event, cpuctx, ctx);
2407 perf_pmu_enable(ctx->pmu);
2411 * Test whether two contexts are equivalent, i.e. whether they have both been
2412 * cloned from the same version of the same context.
2414 * Equivalence is measured using a generation number in the context that is
2415 * incremented on each modification to it; see unclone_ctx(), list_add_event()
2416 * and list_del_event().
2418 static int context_equiv(struct perf_event_context *ctx1,
2419 struct perf_event_context *ctx2)
2421 lockdep_assert_held(&ctx1->lock);
2422 lockdep_assert_held(&ctx2->lock);
2424 /* Pinning disables the swap optimization */
2425 if (ctx1->pin_count || ctx2->pin_count)
2428 /* If ctx1 is the parent of ctx2 */
2429 if (ctx1 == ctx2->parent_ctx && ctx1->generation == ctx2->parent_gen)
2432 /* If ctx2 is the parent of ctx1 */
2433 if (ctx1->parent_ctx == ctx2 && ctx1->parent_gen == ctx2->generation)
2437 * If ctx1 and ctx2 have the same parent; we flatten the parent
2438 * hierarchy, see perf_event_init_context().
2440 if (ctx1->parent_ctx && ctx1->parent_ctx == ctx2->parent_ctx &&
2441 ctx1->parent_gen == ctx2->parent_gen)
2448 static void __perf_event_sync_stat(struct perf_event *event,
2449 struct perf_event *next_event)
2453 if (!event->attr.inherit_stat)
2457 * Update the event value, we cannot use perf_event_read()
2458 * because we're in the middle of a context switch and have IRQs
2459 * disabled, which upsets smp_call_function_single(), however
2460 * we know the event must be on the current CPU, therefore we
2461 * don't need to use it.
2463 switch (event->state) {
2464 case PERF_EVENT_STATE_ACTIVE:
2465 event->pmu->read(event);
2468 case PERF_EVENT_STATE_INACTIVE:
2469 update_event_times(event);
2477 * In order to keep per-task stats reliable we need to flip the event
2478 * values when we flip the contexts.
2480 value = local64_read(&next_event->count);
2481 value = local64_xchg(&event->count, value);
2482 local64_set(&next_event->count, value);
2484 swap(event->total_time_enabled, next_event->total_time_enabled);
2485 swap(event->total_time_running, next_event->total_time_running);
2488 * Since we swizzled the values, update the user visible data too.
2490 perf_event_update_userpage(event);
2491 perf_event_update_userpage(next_event);
2494 static void perf_event_sync_stat(struct perf_event_context *ctx,
2495 struct perf_event_context *next_ctx)
2497 struct perf_event *event, *next_event;
2502 update_context_time(ctx);
2504 event = list_first_entry(&ctx->event_list,
2505 struct perf_event, event_entry);
2507 next_event = list_first_entry(&next_ctx->event_list,
2508 struct perf_event, event_entry);
2510 while (&event->event_entry != &ctx->event_list &&
2511 &next_event->event_entry != &next_ctx->event_list) {
2513 __perf_event_sync_stat(event, next_event);
2515 event = list_next_entry(event, event_entry);
2516 next_event = list_next_entry(next_event, event_entry);
2520 static void perf_event_context_sched_out(struct task_struct *task, int ctxn,
2521 struct task_struct *next)
2523 struct perf_event_context *ctx = task->perf_event_ctxp[ctxn];
2524 struct perf_event_context *next_ctx;
2525 struct perf_event_context *parent, *next_parent;
2526 struct perf_cpu_context *cpuctx;
2532 cpuctx = __get_cpu_context(ctx);
2533 if (!cpuctx->task_ctx)
2537 next_ctx = next->perf_event_ctxp[ctxn];
2541 parent = rcu_dereference(ctx->parent_ctx);
2542 next_parent = rcu_dereference(next_ctx->parent_ctx);
2544 /* If neither context have a parent context; they cannot be clones. */
2545 if (!parent && !next_parent)
2548 if (next_parent == ctx || next_ctx == parent || next_parent == parent) {
2550 * Looks like the two contexts are clones, so we might be
2551 * able to optimize the context switch. We lock both
2552 * contexts and check that they are clones under the
2553 * lock (including re-checking that neither has been
2554 * uncloned in the meantime). It doesn't matter which
2555 * order we take the locks because no other cpu could
2556 * be trying to lock both of these tasks.
2558 raw_spin_lock(&ctx->lock);
2559 raw_spin_lock_nested(&next_ctx->lock, SINGLE_DEPTH_NESTING);
2560 if (context_equiv(ctx, next_ctx)) {
2561 WRITE_ONCE(ctx->task, next);
2562 WRITE_ONCE(next_ctx->task, task);
2564 swap(ctx->task_ctx_data, next_ctx->task_ctx_data);
2567 * RCU_INIT_POINTER here is safe because we've not
2568 * modified the ctx and the above modification of
2569 * ctx->task and ctx->task_ctx_data are immaterial
2570 * since those values are always verified under
2571 * ctx->lock which we're now holding.
2573 RCU_INIT_POINTER(task->perf_event_ctxp[ctxn], next_ctx);
2574 RCU_INIT_POINTER(next->perf_event_ctxp[ctxn], ctx);
2578 perf_event_sync_stat(ctx, next_ctx);
2580 raw_spin_unlock(&next_ctx->lock);
2581 raw_spin_unlock(&ctx->lock);
2587 raw_spin_lock(&ctx->lock);
2588 task_ctx_sched_out(cpuctx, ctx);
2589 raw_spin_unlock(&ctx->lock);
2593 void perf_sched_cb_dec(struct pmu *pmu)
2595 this_cpu_dec(perf_sched_cb_usages);
2598 void perf_sched_cb_inc(struct pmu *pmu)
2600 this_cpu_inc(perf_sched_cb_usages);
2604 * This function provides the context switch callback to the lower code
2605 * layer. It is invoked ONLY when the context switch callback is enabled.
2607 static void perf_pmu_sched_task(struct task_struct *prev,
2608 struct task_struct *next,
2611 struct perf_cpu_context *cpuctx;
2613 unsigned long flags;
2618 local_irq_save(flags);
2622 list_for_each_entry_rcu(pmu, &pmus, entry) {
2623 if (pmu->sched_task) {
2624 cpuctx = this_cpu_ptr(pmu->pmu_cpu_context);
2626 perf_ctx_lock(cpuctx, cpuctx->task_ctx);
2628 perf_pmu_disable(pmu);
2630 pmu->sched_task(cpuctx->task_ctx, sched_in);
2632 perf_pmu_enable(pmu);
2634 perf_ctx_unlock(cpuctx, cpuctx->task_ctx);
2640 local_irq_restore(flags);
2643 static void perf_event_switch(struct task_struct *task,
2644 struct task_struct *next_prev, bool sched_in);
2646 #define for_each_task_context_nr(ctxn) \
2647 for ((ctxn) = 0; (ctxn) < perf_nr_task_contexts; (ctxn)++)
2650 * Called from scheduler to remove the events of the current task,
2651 * with interrupts disabled.
2653 * We stop each event and update the event value in event->count.
2655 * This does not protect us against NMI, but disable()
2656 * sets the disabled bit in the control field of event _before_
2657 * accessing the event control register. If a NMI hits, then it will
2658 * not restart the event.
2660 void __perf_event_task_sched_out(struct task_struct *task,
2661 struct task_struct *next)
2665 if (__this_cpu_read(perf_sched_cb_usages))
2666 perf_pmu_sched_task(task, next, false);
2668 if (atomic_read(&nr_switch_events))
2669 perf_event_switch(task, next, false);
2671 for_each_task_context_nr(ctxn)
2672 perf_event_context_sched_out(task, ctxn, next);
2675 * if cgroup events exist on this CPU, then we need
2676 * to check if we have to switch out PMU state.
2677 * cgroup event are system-wide mode only
2679 if (atomic_read(this_cpu_ptr(&perf_cgroup_events)))
2680 perf_cgroup_sched_out(task, next);
2683 static void task_ctx_sched_out(struct perf_cpu_context *cpuctx,
2684 struct perf_event_context *ctx)
2686 if (!cpuctx->task_ctx)
2689 if (WARN_ON_ONCE(ctx != cpuctx->task_ctx))
2692 ctx_sched_out(ctx, cpuctx, EVENT_ALL);
2696 * Called with IRQs disabled
2698 static void cpu_ctx_sched_out(struct perf_cpu_context *cpuctx,
2699 enum event_type_t event_type)
2701 ctx_sched_out(&cpuctx->ctx, cpuctx, event_type);
2705 ctx_pinned_sched_in(struct perf_event_context *ctx,
2706 struct perf_cpu_context *cpuctx)
2708 struct perf_event *event;
2710 list_for_each_entry(event, &ctx->pinned_groups, group_entry) {
2711 if (event->state <= PERF_EVENT_STATE_OFF)
2713 if (!event_filter_match(event))
2716 /* may need to reset tstamp_enabled */
2717 if (is_cgroup_event(event))
2718 perf_cgroup_mark_enabled(event, ctx);
2720 if (group_can_go_on(event, cpuctx, 1))
2721 group_sched_in(event, cpuctx, ctx);
2724 * If this pinned group hasn't been scheduled,
2725 * put it in error state.
2727 if (event->state == PERF_EVENT_STATE_INACTIVE) {
2728 update_group_times(event);
2729 event->state = PERF_EVENT_STATE_ERROR;
2735 ctx_flexible_sched_in(struct perf_event_context *ctx,
2736 struct perf_cpu_context *cpuctx)
2738 struct perf_event *event;
2741 list_for_each_entry(event, &ctx->flexible_groups, group_entry) {
2742 /* Ignore events in OFF or ERROR state */
2743 if (event->state <= PERF_EVENT_STATE_OFF)
2746 * Listen to the 'cpu' scheduling filter constraint
2749 if (!event_filter_match(event))
2752 /* may need to reset tstamp_enabled */
2753 if (is_cgroup_event(event))
2754 perf_cgroup_mark_enabled(event, ctx);
2756 if (group_can_go_on(event, cpuctx, can_add_hw)) {
2757 if (group_sched_in(event, cpuctx, ctx))
2764 ctx_sched_in(struct perf_event_context *ctx,
2765 struct perf_cpu_context *cpuctx,
2766 enum event_type_t event_type,
2767 struct task_struct *task)
2769 int is_active = ctx->is_active;
2772 lockdep_assert_held(&ctx->lock);
2774 if (likely(!ctx->nr_events))
2777 ctx->is_active |= event_type;
2780 cpuctx->task_ctx = ctx;
2782 WARN_ON_ONCE(cpuctx->task_ctx != ctx);
2786 ctx->timestamp = now;
2787 perf_cgroup_set_timestamp(task, ctx);
2789 * First go through the list and put on any pinned groups
2790 * in order to give them the best chance of going on.
2792 if (!(is_active & EVENT_PINNED) && (event_type & EVENT_PINNED))
2793 ctx_pinned_sched_in(ctx, cpuctx);
2795 /* Then walk through the lower prio flexible groups */
2796 if (!(is_active & EVENT_FLEXIBLE) && (event_type & EVENT_FLEXIBLE))
2797 ctx_flexible_sched_in(ctx, cpuctx);
2800 static void cpu_ctx_sched_in(struct perf_cpu_context *cpuctx,
2801 enum event_type_t event_type,
2802 struct task_struct *task)
2804 struct perf_event_context *ctx = &cpuctx->ctx;
2806 ctx_sched_in(ctx, cpuctx, event_type, task);
2809 static void perf_event_context_sched_in(struct perf_event_context *ctx,
2810 struct task_struct *task)
2812 struct perf_cpu_context *cpuctx;
2814 cpuctx = __get_cpu_context(ctx);
2815 if (cpuctx->task_ctx == ctx)
2818 perf_ctx_lock(cpuctx, ctx);
2819 perf_pmu_disable(ctx->pmu);
2821 * We want to keep the following priority order:
2822 * cpu pinned (that don't need to move), task pinned,
2823 * cpu flexible, task flexible.
2825 cpu_ctx_sched_out(cpuctx, EVENT_FLEXIBLE);
2826 perf_event_sched_in(cpuctx, ctx, task);
2827 perf_pmu_enable(ctx->pmu);
2828 perf_ctx_unlock(cpuctx, ctx);
2832 * Called from scheduler to add the events of the current task
2833 * with interrupts disabled.
2835 * We restore the event value and then enable it.
2837 * This does not protect us against NMI, but enable()
2838 * sets the enabled bit in the control field of event _before_
2839 * accessing the event control register. If a NMI hits, then it will
2840 * keep the event running.
2842 void __perf_event_task_sched_in(struct task_struct *prev,
2843 struct task_struct *task)
2845 struct perf_event_context *ctx;
2849 * If cgroup events exist on this CPU, then we need to check if we have
2850 * to switch in PMU state; cgroup event are system-wide mode only.
2852 * Since cgroup events are CPU events, we must schedule these in before
2853 * we schedule in the task events.
2855 if (atomic_read(this_cpu_ptr(&perf_cgroup_events)))
2856 perf_cgroup_sched_in(prev, task);
2858 for_each_task_context_nr(ctxn) {
2859 ctx = task->perf_event_ctxp[ctxn];
2863 perf_event_context_sched_in(ctx, task);
2866 if (atomic_read(&nr_switch_events))
2867 perf_event_switch(task, prev, true);
2869 if (__this_cpu_read(perf_sched_cb_usages))
2870 perf_pmu_sched_task(prev, task, true);
2873 static u64 perf_calculate_period(struct perf_event *event, u64 nsec, u64 count)
2875 u64 frequency = event->attr.sample_freq;
2876 u64 sec = NSEC_PER_SEC;
2877 u64 divisor, dividend;
2879 int count_fls, nsec_fls, frequency_fls, sec_fls;
2881 count_fls = fls64(count);
2882 nsec_fls = fls64(nsec);
2883 frequency_fls = fls64(frequency);
2887 * We got @count in @nsec, with a target of sample_freq HZ
2888 * the target period becomes:
2891 * period = -------------------
2892 * @nsec * sample_freq
2897 * Reduce accuracy by one bit such that @a and @b converge
2898 * to a similar magnitude.
2900 #define REDUCE_FLS(a, b) \
2902 if (a##_fls > b##_fls) { \
2912 * Reduce accuracy until either term fits in a u64, then proceed with
2913 * the other, so that finally we can do a u64/u64 division.
2915 while (count_fls + sec_fls > 64 && nsec_fls + frequency_fls > 64) {
2916 REDUCE_FLS(nsec, frequency);
2917 REDUCE_FLS(sec, count);
2920 if (count_fls + sec_fls > 64) {
2921 divisor = nsec * frequency;
2923 while (count_fls + sec_fls > 64) {
2924 REDUCE_FLS(count, sec);
2928 dividend = count * sec;
2930 dividend = count * sec;
2932 while (nsec_fls + frequency_fls > 64) {
2933 REDUCE_FLS(nsec, frequency);
2937 divisor = nsec * frequency;
2943 return div64_u64(dividend, divisor);
2946 static DEFINE_PER_CPU(int, perf_throttled_count);
2947 static DEFINE_PER_CPU(u64, perf_throttled_seq);
2949 static void perf_adjust_period(struct perf_event *event, u64 nsec, u64 count, bool disable)
2951 struct hw_perf_event *hwc = &event->hw;
2952 s64 period, sample_period;
2955 period = perf_calculate_period(event, nsec, count);
2957 delta = (s64)(period - hwc->sample_period);
2958 delta = (delta + 7) / 8; /* low pass filter */
2960 sample_period = hwc->sample_period + delta;
2965 hwc->sample_period = sample_period;
2967 if (local64_read(&hwc->period_left) > 8*sample_period) {
2969 event->pmu->stop(event, PERF_EF_UPDATE);
2971 local64_set(&hwc->period_left, 0);
2974 event->pmu->start(event, PERF_EF_RELOAD);
2979 * combine freq adjustment with unthrottling to avoid two passes over the
2980 * events. At the same time, make sure, having freq events does not change
2981 * the rate of unthrottling as that would introduce bias.
2983 static void perf_adjust_freq_unthr_context(struct perf_event_context *ctx,
2986 struct perf_event *event;
2987 struct hw_perf_event *hwc;
2988 u64 now, period = TICK_NSEC;
2992 * only need to iterate over all events iff:
2993 * - context have events in frequency mode (needs freq adjust)
2994 * - there are events to unthrottle on this cpu
2996 if (!(ctx->nr_freq || needs_unthr))
2999 raw_spin_lock(&ctx->lock);
3000 perf_pmu_disable(ctx->pmu);
3002 list_for_each_entry_rcu(event, &ctx->event_list, event_entry) {
3003 if (event->state != PERF_EVENT_STATE_ACTIVE)
3006 if (!event_filter_match(event))
3009 perf_pmu_disable(event->pmu);
3013 if (hwc->interrupts == MAX_INTERRUPTS) {
3014 hwc->interrupts = 0;
3015 perf_log_throttle(event, 1);
3016 event->pmu->start(event, 0);
3019 if (!event->attr.freq || !event->attr.sample_freq)
3023 * stop the event and update event->count
3025 event->pmu->stop(event, PERF_EF_UPDATE);
3027 now = local64_read(&event->count);
3028 delta = now - hwc->freq_count_stamp;
3029 hwc->freq_count_stamp = now;
3033 * reload only if value has changed
3034 * we have stopped the event so tell that
3035 * to perf_adjust_period() to avoid stopping it
3039 perf_adjust_period(event, period, delta, false);
3041 event->pmu->start(event, delta > 0 ? PERF_EF_RELOAD : 0);
3043 perf_pmu_enable(event->pmu);
3046 perf_pmu_enable(ctx->pmu);
3047 raw_spin_unlock(&ctx->lock);
3051 * Round-robin a context's events:
3053 static void rotate_ctx(struct perf_event_context *ctx)
3056 * Rotate the first entry last of non-pinned groups. Rotation might be
3057 * disabled by the inheritance code.
3059 if (!ctx->rotate_disable)
3060 list_rotate_left(&ctx->flexible_groups);
3063 static int perf_rotate_context(struct perf_cpu_context *cpuctx)
3065 struct perf_event_context *ctx = NULL;
3068 if (cpuctx->ctx.nr_events) {
3069 if (cpuctx->ctx.nr_events != cpuctx->ctx.nr_active)
3073 ctx = cpuctx->task_ctx;
3074 if (ctx && ctx->nr_events) {
3075 if (ctx->nr_events != ctx->nr_active)
3082 perf_ctx_lock(cpuctx, cpuctx->task_ctx);
3083 perf_pmu_disable(cpuctx->ctx.pmu);
3085 cpu_ctx_sched_out(cpuctx, EVENT_FLEXIBLE);
3087 ctx_sched_out(ctx, cpuctx, EVENT_FLEXIBLE);
3089 rotate_ctx(&cpuctx->ctx);
3093 perf_event_sched_in(cpuctx, ctx, current);
3095 perf_pmu_enable(cpuctx->ctx.pmu);
3096 perf_ctx_unlock(cpuctx, cpuctx->task_ctx);
3102 #ifdef CONFIG_NO_HZ_FULL
3103 bool perf_event_can_stop_tick(void)
3105 if (atomic_read(&nr_freq_events) ||
3106 __this_cpu_read(perf_throttled_count))
3113 void perf_event_task_tick(void)
3115 struct list_head *head = this_cpu_ptr(&active_ctx_list);
3116 struct perf_event_context *ctx, *tmp;
3119 WARN_ON(!irqs_disabled());
3121 __this_cpu_inc(perf_throttled_seq);
3122 throttled = __this_cpu_xchg(perf_throttled_count, 0);
3124 list_for_each_entry_safe(ctx, tmp, head, active_ctx_list)
3125 perf_adjust_freq_unthr_context(ctx, throttled);
3128 static int event_enable_on_exec(struct perf_event *event,
3129 struct perf_event_context *ctx)
3131 if (!event->attr.enable_on_exec)
3134 event->attr.enable_on_exec = 0;
3135 if (event->state >= PERF_EVENT_STATE_INACTIVE)
3138 __perf_event_mark_enabled(event);
3144 * Enable all of a task's events that have been marked enable-on-exec.
3145 * This expects task == current.
3147 static void perf_event_enable_on_exec(int ctxn)
3149 struct perf_event_context *ctx, *clone_ctx = NULL;
3150 struct perf_cpu_context *cpuctx;
3151 struct perf_event *event;
3152 unsigned long flags;
3155 local_irq_save(flags);
3156 ctx = current->perf_event_ctxp[ctxn];
3157 if (!ctx || !ctx->nr_events)
3160 cpuctx = __get_cpu_context(ctx);
3161 perf_ctx_lock(cpuctx, ctx);
3162 list_for_each_entry(event, &ctx->event_list, event_entry)
3163 enabled |= event_enable_on_exec(event, ctx);
3166 * Unclone and reschedule this context if we enabled any event.
3169 clone_ctx = unclone_ctx(ctx);
3170 ctx_resched(cpuctx, ctx);
3172 perf_ctx_unlock(cpuctx, ctx);
3175 local_irq_restore(flags);
3181 void perf_event_exec(void)
3186 for_each_task_context_nr(ctxn)
3187 perf_event_enable_on_exec(ctxn);
3191 struct perf_read_data {
3192 struct perf_event *event;
3198 * Cross CPU call to read the hardware event
3200 static void __perf_event_read(void *info)
3202 struct perf_read_data *data = info;
3203 struct perf_event *sub, *event = data->event;
3204 struct perf_event_context *ctx = event->ctx;
3205 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
3206 struct pmu *pmu = event->pmu;
3209 * If this is a task context, we need to check whether it is
3210 * the current task context of this cpu. If not it has been
3211 * scheduled out before the smp call arrived. In that case
3212 * event->count would have been updated to a recent sample
3213 * when the event was scheduled out.
3215 if (ctx->task && cpuctx->task_ctx != ctx)
3218 raw_spin_lock(&ctx->lock);
3219 if (ctx->is_active) {
3220 update_context_time(ctx);
3221 update_cgrp_time_from_event(event);
3224 update_event_times(event);
3225 if (event->state != PERF_EVENT_STATE_ACTIVE)
3234 pmu->start_txn(pmu, PERF_PMU_TXN_READ);
3238 list_for_each_entry(sub, &event->sibling_list, group_entry) {
3239 update_event_times(sub);
3240 if (sub->state == PERF_EVENT_STATE_ACTIVE) {
3242 * Use sibling's PMU rather than @event's since
3243 * sibling could be on different (eg: software) PMU.
3245 sub->pmu->read(sub);
3249 data->ret = pmu->commit_txn(pmu);
3252 raw_spin_unlock(&ctx->lock);
3255 static inline u64 perf_event_count(struct perf_event *event)
3257 if (event->pmu->count)
3258 return event->pmu->count(event);
3260 return __perf_event_count(event);
3264 * NMI-safe method to read a local event, that is an event that
3266 * - either for the current task, or for this CPU
3267 * - does not have inherit set, for inherited task events
3268 * will not be local and we cannot read them atomically
3269 * - must not have a pmu::count method
3271 u64 perf_event_read_local(struct perf_event *event)
3273 unsigned long flags;
3277 * Disabling interrupts avoids all counter scheduling (context
3278 * switches, timer based rotation and IPIs).
3280 local_irq_save(flags);
3282 /* If this is a per-task event, it must be for current */
3283 WARN_ON_ONCE((event->attach_state & PERF_ATTACH_TASK) &&
3284 event->hw.target != current);
3286 /* If this is a per-CPU event, it must be for this CPU */
3287 WARN_ON_ONCE(!(event->attach_state & PERF_ATTACH_TASK) &&
3288 event->cpu != smp_processor_id());
3291 * It must not be an event with inherit set, we cannot read
3292 * all child counters from atomic context.
3294 WARN_ON_ONCE(event->attr.inherit);
3297 * It must not have a pmu::count method, those are not
3300 WARN_ON_ONCE(event->pmu->count);
3303 * If the event is currently on this CPU, its either a per-task event,
3304 * or local to this CPU. Furthermore it means its ACTIVE (otherwise
3307 if (event->oncpu == smp_processor_id())
3308 event->pmu->read(event);
3310 val = local64_read(&event->count);
3311 local_irq_restore(flags);
3316 static int perf_event_read(struct perf_event *event, bool group)
3321 * If event is enabled and currently active on a CPU, update the
3322 * value in the event structure:
3324 if (event->state == PERF_EVENT_STATE_ACTIVE) {
3325 struct perf_read_data data = {
3330 smp_call_function_single(event->oncpu,
3331 __perf_event_read, &data, 1);
3333 } else if (event->state == PERF_EVENT_STATE_INACTIVE) {
3334 struct perf_event_context *ctx = event->ctx;
3335 unsigned long flags;
3337 raw_spin_lock_irqsave(&ctx->lock, flags);
3339 * may read while context is not active
3340 * (e.g., thread is blocked), in that case
3341 * we cannot update context time
3343 if (ctx->is_active) {
3344 update_context_time(ctx);
3345 update_cgrp_time_from_event(event);
3348 update_group_times(event);
3350 update_event_times(event);
3351 raw_spin_unlock_irqrestore(&ctx->lock, flags);
3358 * Initialize the perf_event context in a task_struct:
3360 static void __perf_event_init_context(struct perf_event_context *ctx)
3362 raw_spin_lock_init(&ctx->lock);
3363 mutex_init(&ctx->mutex);
3364 INIT_LIST_HEAD(&ctx->active_ctx_list);
3365 INIT_LIST_HEAD(&ctx->pinned_groups);
3366 INIT_LIST_HEAD(&ctx->flexible_groups);
3367 INIT_LIST_HEAD(&ctx->event_list);
3368 atomic_set(&ctx->refcount, 1);
3369 INIT_DELAYED_WORK(&ctx->orphans_remove, orphans_remove_work);
3372 static struct perf_event_context *
3373 alloc_perf_context(struct pmu *pmu, struct task_struct *task)
3375 struct perf_event_context *ctx;
3377 ctx = kzalloc(sizeof(struct perf_event_context), GFP_KERNEL);
3381 __perf_event_init_context(ctx);
3384 get_task_struct(task);
3391 static struct task_struct *
3392 find_lively_task_by_vpid(pid_t vpid)
3394 struct task_struct *task;
3401 task = find_task_by_vpid(vpid);
3403 get_task_struct(task);
3407 return ERR_PTR(-ESRCH);
3409 /* Reuse ptrace permission checks for now. */
3411 if (!ptrace_may_access(task, PTRACE_MODE_READ))
3416 put_task_struct(task);
3417 return ERR_PTR(err);
3422 * Returns a matching context with refcount and pincount.
3424 static struct perf_event_context *
3425 find_get_context(struct pmu *pmu, struct task_struct *task,
3426 struct perf_event *event)
3428 struct perf_event_context *ctx, *clone_ctx = NULL;
3429 struct perf_cpu_context *cpuctx;
3430 void *task_ctx_data = NULL;
3431 unsigned long flags;
3433 int cpu = event->cpu;
3436 /* Must be root to operate on a CPU event: */
3437 if (perf_paranoid_cpu() && !capable(CAP_SYS_ADMIN))
3438 return ERR_PTR(-EACCES);
3441 * We could be clever and allow to attach a event to an
3442 * offline CPU and activate it when the CPU comes up, but
3445 if (!cpu_online(cpu))
3446 return ERR_PTR(-ENODEV);
3448 cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
3457 ctxn = pmu->task_ctx_nr;
3461 if (event->attach_state & PERF_ATTACH_TASK_DATA) {
3462 task_ctx_data = kzalloc(pmu->task_ctx_size, GFP_KERNEL);
3463 if (!task_ctx_data) {
3470 ctx = perf_lock_task_context(task, ctxn, &flags);
3472 clone_ctx = unclone_ctx(ctx);
3475 if (task_ctx_data && !ctx->task_ctx_data) {
3476 ctx->task_ctx_data = task_ctx_data;
3477 task_ctx_data = NULL;
3479 raw_spin_unlock_irqrestore(&ctx->lock, flags);
3484 ctx = alloc_perf_context(pmu, task);
3489 if (task_ctx_data) {
3490 ctx->task_ctx_data = task_ctx_data;
3491 task_ctx_data = NULL;
3495 mutex_lock(&task->perf_event_mutex);
3497 * If it has already passed perf_event_exit_task().
3498 * we must see PF_EXITING, it takes this mutex too.
3500 if (task->flags & PF_EXITING)
3502 else if (task->perf_event_ctxp[ctxn])
3507 rcu_assign_pointer(task->perf_event_ctxp[ctxn], ctx);
3509 mutex_unlock(&task->perf_event_mutex);
3511 if (unlikely(err)) {
3520 kfree(task_ctx_data);
3524 kfree(task_ctx_data);
3525 return ERR_PTR(err);
3528 static void perf_event_free_filter(struct perf_event *event);
3529 static void perf_event_free_bpf_prog(struct perf_event *event);
3531 static void free_event_rcu(struct rcu_head *head)
3533 struct perf_event *event;
3535 event = container_of(head, struct perf_event, rcu_head);
3537 put_pid_ns(event->ns);
3538 perf_event_free_filter(event);
3542 static void ring_buffer_attach(struct perf_event *event,
3543 struct ring_buffer *rb);
3545 static void unaccount_event_cpu(struct perf_event *event, int cpu)
3550 if (is_cgroup_event(event))
3551 atomic_dec(&per_cpu(perf_cgroup_events, cpu));
3554 static void unaccount_event(struct perf_event *event)
3561 if (event->attach_state & PERF_ATTACH_TASK)
3563 if (event->attr.mmap || event->attr.mmap_data)
3564 atomic_dec(&nr_mmap_events);
3565 if (event->attr.comm)
3566 atomic_dec(&nr_comm_events);
3567 if (event->attr.task)
3568 atomic_dec(&nr_task_events);
3569 if (event->attr.freq)
3570 atomic_dec(&nr_freq_events);
3571 if (event->attr.context_switch) {
3573 atomic_dec(&nr_switch_events);
3575 if (is_cgroup_event(event))
3577 if (has_branch_stack(event))
3581 static_key_slow_dec_deferred(&perf_sched_events);
3583 unaccount_event_cpu(event, event->cpu);
3587 * The following implement mutual exclusion of events on "exclusive" pmus
3588 * (PERF_PMU_CAP_EXCLUSIVE). Such pmus can only have one event scheduled
3589 * at a time, so we disallow creating events that might conflict, namely:
3591 * 1) cpu-wide events in the presence of per-task events,
3592 * 2) per-task events in the presence of cpu-wide events,
3593 * 3) two matching events on the same context.
3595 * The former two cases are handled in the allocation path (perf_event_alloc(),
3596 * _free_event()), the latter -- before the first perf_install_in_context().
3598 static int exclusive_event_init(struct perf_event *event)
3600 struct pmu *pmu = event->pmu;
3602 if (!(pmu->capabilities & PERF_PMU_CAP_EXCLUSIVE))
3606 * Prevent co-existence of per-task and cpu-wide events on the
3607 * same exclusive pmu.
3609 * Negative pmu::exclusive_cnt means there are cpu-wide
3610 * events on this "exclusive" pmu, positive means there are
3613 * Since this is called in perf_event_alloc() path, event::ctx
3614 * doesn't exist yet; it is, however, safe to use PERF_ATTACH_TASK
3615 * to mean "per-task event", because unlike other attach states it
3616 * never gets cleared.
3618 if (event->attach_state & PERF_ATTACH_TASK) {
3619 if (!atomic_inc_unless_negative(&pmu->exclusive_cnt))
3622 if (!atomic_dec_unless_positive(&pmu->exclusive_cnt))
3629 static void exclusive_event_destroy(struct perf_event *event)
3631 struct pmu *pmu = event->pmu;
3633 if (!(pmu->capabilities & PERF_PMU_CAP_EXCLUSIVE))
3636 /* see comment in exclusive_event_init() */
3637 if (event->attach_state & PERF_ATTACH_TASK)
3638 atomic_dec(&pmu->exclusive_cnt);
3640 atomic_inc(&pmu->exclusive_cnt);
3643 static bool exclusive_event_match(struct perf_event *e1, struct perf_event *e2)
3645 if ((e1->pmu->capabilities & PERF_PMU_CAP_EXCLUSIVE) &&
3646 (e1->cpu == e2->cpu ||
3653 /* Called under the same ctx::mutex as perf_install_in_context() */
3654 static bool exclusive_event_installable(struct perf_event *event,
3655 struct perf_event_context *ctx)
3657 struct perf_event *iter_event;
3658 struct pmu *pmu = event->pmu;
3660 if (!(pmu->capabilities & PERF_PMU_CAP_EXCLUSIVE))
3663 list_for_each_entry(iter_event, &ctx->event_list, event_entry) {
3664 if (exclusive_event_match(iter_event, event))
3671 static void _free_event(struct perf_event *event)
3673 irq_work_sync(&event->pending);
3675 unaccount_event(event);
3679 * Can happen when we close an event with re-directed output.
3681 * Since we have a 0 refcount, perf_mmap_close() will skip
3682 * over us; possibly making our ring_buffer_put() the last.
3684 mutex_lock(&event->mmap_mutex);
3685 ring_buffer_attach(event, NULL);
3686 mutex_unlock(&event->mmap_mutex);
3689 if (is_cgroup_event(event))
3690 perf_detach_cgroup(event);
3692 if (!event->parent) {
3693 if (event->attr.sample_type & PERF_SAMPLE_CALLCHAIN)
3694 put_callchain_buffers();
3697 perf_event_free_bpf_prog(event);
3700 event->destroy(event);
3703 put_ctx(event->ctx);
3706 exclusive_event_destroy(event);
3707 module_put(event->pmu->module);
3710 call_rcu(&event->rcu_head, free_event_rcu);
3714 * Used to free events which have a known refcount of 1, such as in error paths
3715 * where the event isn't exposed yet and inherited events.
3717 static void free_event(struct perf_event *event)
3719 if (WARN(atomic_long_cmpxchg(&event->refcount, 1, 0) != 1,
3720 "unexpected event refcount: %ld; ptr=%p\n",
3721 atomic_long_read(&event->refcount), event)) {
3722 /* leak to avoid use-after-free */
3730 * Remove user event from the owner task.
3732 static void perf_remove_from_owner(struct perf_event *event)
3734 struct task_struct *owner;
3738 * Matches the smp_store_release() in perf_event_exit_task(). If we
3739 * observe !owner it means the list deletion is complete and we can
3740 * indeed free this event, otherwise we need to serialize on
3741 * owner->perf_event_mutex.
3743 owner = lockless_dereference(event->owner);
3746 * Since delayed_put_task_struct() also drops the last
3747 * task reference we can safely take a new reference
3748 * while holding the rcu_read_lock().
3750 get_task_struct(owner);
3756 * If we're here through perf_event_exit_task() we're already
3757 * holding ctx->mutex which would be an inversion wrt. the
3758 * normal lock order.
3760 * However we can safely take this lock because its the child
3763 mutex_lock_nested(&owner->perf_event_mutex, SINGLE_DEPTH_NESTING);
3766 * We have to re-check the event->owner field, if it is cleared
3767 * we raced with perf_event_exit_task(), acquiring the mutex
3768 * ensured they're done, and we can proceed with freeing the
3772 list_del_init(&event->owner_entry);
3773 smp_store_release(&event->owner, NULL);
3775 mutex_unlock(&owner->perf_event_mutex);
3776 put_task_struct(owner);
3780 static void put_event(struct perf_event *event)
3782 struct perf_event_context *ctx;
3784 if (!atomic_long_dec_and_test(&event->refcount))
3787 if (!is_kernel_event(event))
3788 perf_remove_from_owner(event);
3791 * There are two ways this annotation is useful:
3793 * 1) there is a lock recursion from perf_event_exit_task
3794 * see the comment there.
3796 * 2) there is a lock-inversion with mmap_sem through
3797 * perf_read_group(), which takes faults while
3798 * holding ctx->mutex, however this is called after
3799 * the last filedesc died, so there is no possibility
3800 * to trigger the AB-BA case.
3802 ctx = perf_event_ctx_lock_nested(event, SINGLE_DEPTH_NESTING);
3803 WARN_ON_ONCE(ctx->parent_ctx);
3804 perf_remove_from_context(event, DETACH_GROUP);
3805 perf_event_ctx_unlock(event, ctx);
3810 int perf_event_release_kernel(struct perf_event *event)
3815 EXPORT_SYMBOL_GPL(perf_event_release_kernel);
3818 * Called when the last reference to the file is gone.
3820 static int perf_release(struct inode *inode, struct file *file)
3822 put_event(file->private_data);
3827 * Remove all orphanes events from the context.
3829 static void orphans_remove_work(struct work_struct *work)
3831 struct perf_event_context *ctx;
3832 struct perf_event *event, *tmp;
3834 ctx = container_of(work, struct perf_event_context,
3835 orphans_remove.work);
3837 mutex_lock(&ctx->mutex);
3838 list_for_each_entry_safe(event, tmp, &ctx->event_list, event_entry) {
3839 struct perf_event *parent_event = event->parent;
3841 if (!is_orphaned_child(event))
3844 perf_remove_from_context(event, DETACH_GROUP);
3846 mutex_lock(&parent_event->child_mutex);
3847 list_del_init(&event->child_list);
3848 mutex_unlock(&parent_event->child_mutex);
3851 put_event(parent_event);
3854 raw_spin_lock_irq(&ctx->lock);
3855 ctx->orphans_remove_sched = false;
3856 raw_spin_unlock_irq(&ctx->lock);
3857 mutex_unlock(&ctx->mutex);
3862 u64 perf_event_read_value(struct perf_event *event, u64 *enabled, u64 *running)
3864 struct perf_event *child;
3870 mutex_lock(&event->child_mutex);
3872 (void)perf_event_read(event, false);
3873 total += perf_event_count(event);
3875 *enabled += event->total_time_enabled +
3876 atomic64_read(&event->child_total_time_enabled);
3877 *running += event->total_time_running +
3878 atomic64_read(&event->child_total_time_running);
3880 list_for_each_entry(child, &event->child_list, child_list) {
3881 (void)perf_event_read(child, false);
3882 total += perf_event_count(child);
3883 *enabled += child->total_time_enabled;
3884 *running += child->total_time_running;
3886 mutex_unlock(&event->child_mutex);
3890 EXPORT_SYMBOL_GPL(perf_event_read_value);
3892 static int __perf_read_group_add(struct perf_event *leader,
3893 u64 read_format, u64 *values)
3895 struct perf_event *sub;
3896 int n = 1; /* skip @nr */
3899 ret = perf_event_read(leader, true);
3904 * Since we co-schedule groups, {enabled,running} times of siblings
3905 * will be identical to those of the leader, so we only publish one
3908 if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED) {
3909 values[n++] += leader->total_time_enabled +
3910 atomic64_read(&leader->child_total_time_enabled);
3913 if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING) {
3914 values[n++] += leader->total_time_running +
3915 atomic64_read(&leader->child_total_time_running);
3919 * Write {count,id} tuples for every sibling.
3921 values[n++] += perf_event_count(leader);
3922 if (read_format & PERF_FORMAT_ID)
3923 values[n++] = primary_event_id(leader);
3925 list_for_each_entry(sub, &leader->sibling_list, group_entry) {
3926 values[n++] += perf_event_count(sub);
3927 if (read_format & PERF_FORMAT_ID)
3928 values[n++] = primary_event_id(sub);
3934 static int perf_read_group(struct perf_event *event,
3935 u64 read_format, char __user *buf)
3937 struct perf_event *leader = event->group_leader, *child;
3938 struct perf_event_context *ctx = leader->ctx;
3942 lockdep_assert_held(&ctx->mutex);
3944 values = kzalloc(event->read_size, GFP_KERNEL);
3948 values[0] = 1 + leader->nr_siblings;
3951 * By locking the child_mutex of the leader we effectively
3952 * lock the child list of all siblings.. XXX explain how.
3954 mutex_lock(&leader->child_mutex);
3956 ret = __perf_read_group_add(leader, read_format, values);
3960 list_for_each_entry(child, &leader->child_list, child_list) {
3961 ret = __perf_read_group_add(child, read_format, values);
3966 mutex_unlock(&leader->child_mutex);
3968 ret = event->read_size;
3969 if (copy_to_user(buf, values, event->read_size))
3974 mutex_unlock(&leader->child_mutex);
3980 static int perf_read_one(struct perf_event *event,
3981 u64 read_format, char __user *buf)
3983 u64 enabled, running;
3987 values[n++] = perf_event_read_value(event, &enabled, &running);
3988 if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED)
3989 values[n++] = enabled;
3990 if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING)
3991 values[n++] = running;
3992 if (read_format & PERF_FORMAT_ID)
3993 values[n++] = primary_event_id(event);
3995 if (copy_to_user(buf, values, n * sizeof(u64)))
3998 return n * sizeof(u64);
4001 static bool is_event_hup(struct perf_event *event)
4005 if (event->state != PERF_EVENT_STATE_EXIT)
4008 mutex_lock(&event->child_mutex);
4009 no_children = list_empty(&event->child_list);
4010 mutex_unlock(&event->child_mutex);
4015 * Read the performance event - simple non blocking version for now
4018 __perf_read(struct perf_event *event, char __user *buf, size_t count)
4020 u64 read_format = event->attr.read_format;
4024 * Return end-of-file for a read on a event that is in
4025 * error state (i.e. because it was pinned but it couldn't be
4026 * scheduled on to the CPU at some point).
4028 if (event->state == PERF_EVENT_STATE_ERROR)
4031 if (count < event->read_size)
4034 WARN_ON_ONCE(event->ctx->parent_ctx);
4035 if (read_format & PERF_FORMAT_GROUP)
4036 ret = perf_read_group(event, read_format, buf);
4038 ret = perf_read_one(event, read_format, buf);
4044 perf_read(struct file *file, char __user *buf, size_t count, loff_t *ppos)
4046 struct perf_event *event = file->private_data;
4047 struct perf_event_context *ctx;
4050 ctx = perf_event_ctx_lock(event);
4051 ret = __perf_read(event, buf, count);
4052 perf_event_ctx_unlock(event, ctx);
4057 static unsigned int perf_poll(struct file *file, poll_table *wait)
4059 struct perf_event *event = file->private_data;
4060 struct ring_buffer *rb;
4061 unsigned int events = POLLHUP;
4063 poll_wait(file, &event->waitq, wait);
4065 if (is_event_hup(event))
4069 * Pin the event->rb by taking event->mmap_mutex; otherwise
4070 * perf_event_set_output() can swizzle our rb and make us miss wakeups.
4072 mutex_lock(&event->mmap_mutex);
4075 events = atomic_xchg(&rb->poll, 0);
4076 mutex_unlock(&event->mmap_mutex);
4080 static void _perf_event_reset(struct perf_event *event)
4082 (void)perf_event_read(event, false);
4083 local64_set(&event->count, 0);
4084 perf_event_update_userpage(event);
4088 * Holding the top-level event's child_mutex means that any
4089 * descendant process that has inherited this event will block
4090 * in perf_event_exit_event() if it goes to exit, thus satisfying the
4091 * task existence requirements of perf_event_enable/disable.
4093 static void perf_event_for_each_child(struct perf_event *event,
4094 void (*func)(struct perf_event *))
4096 struct perf_event *child;
4098 WARN_ON_ONCE(event->ctx->parent_ctx);
4100 mutex_lock(&event->child_mutex);
4102 list_for_each_entry(child, &event->child_list, child_list)
4104 mutex_unlock(&event->child_mutex);
4107 static void perf_event_for_each(struct perf_event *event,
4108 void (*func)(struct perf_event *))
4110 struct perf_event_context *ctx = event->ctx;
4111 struct perf_event *sibling;
4113 lockdep_assert_held(&ctx->mutex);
4115 event = event->group_leader;
4117 perf_event_for_each_child(event, func);
4118 list_for_each_entry(sibling, &event->sibling_list, group_entry)
4119 perf_event_for_each_child(sibling, func);
4122 static void __perf_event_period(struct perf_event *event,
4123 struct perf_cpu_context *cpuctx,
4124 struct perf_event_context *ctx,
4127 u64 value = *((u64 *)info);
4130 if (event->attr.freq) {
4131 event->attr.sample_freq = value;
4133 event->attr.sample_period = value;
4134 event->hw.sample_period = value;
4137 active = (event->state == PERF_EVENT_STATE_ACTIVE);
4139 perf_pmu_disable(ctx->pmu);
4140 event->pmu->stop(event, PERF_EF_UPDATE);
4143 local64_set(&event->hw.period_left, 0);
4146 event->pmu->start(event, PERF_EF_RELOAD);
4147 perf_pmu_enable(ctx->pmu);
4151 static int perf_event_period(struct perf_event *event, u64 __user *arg)
4155 if (!is_sampling_event(event))
4158 if (copy_from_user(&value, arg, sizeof(value)))
4164 if (event->attr.freq && value > sysctl_perf_event_sample_rate)
4167 event_function_call(event, __perf_event_period, &value);
4172 static const struct file_operations perf_fops;
4174 static inline int perf_fget_light(int fd, struct fd *p)
4176 struct fd f = fdget(fd);
4180 if (f.file->f_op != &perf_fops) {
4188 static int perf_event_set_output(struct perf_event *event,
4189 struct perf_event *output_event);
4190 static int perf_event_set_filter(struct perf_event *event, void __user *arg);
4191 static int perf_event_set_bpf_prog(struct perf_event *event, u32 prog_fd);
4193 static long _perf_ioctl(struct perf_event *event, unsigned int cmd, unsigned long arg)
4195 void (*func)(struct perf_event *);
4199 case PERF_EVENT_IOC_ENABLE:
4200 func = _perf_event_enable;
4202 case PERF_EVENT_IOC_DISABLE:
4203 func = _perf_event_disable;
4205 case PERF_EVENT_IOC_RESET:
4206 func = _perf_event_reset;
4209 case PERF_EVENT_IOC_REFRESH:
4210 return _perf_event_refresh(event, arg);
4212 case PERF_EVENT_IOC_PERIOD:
4213 return perf_event_period(event, (u64 __user *)arg);
4215 case PERF_EVENT_IOC_ID:
4217 u64 id = primary_event_id(event);
4219 if (copy_to_user((void __user *)arg, &id, sizeof(id)))
4224 case PERF_EVENT_IOC_SET_OUTPUT:
4228 struct perf_event *output_event;
4230 ret = perf_fget_light(arg, &output);
4233 output_event = output.file->private_data;
4234 ret = perf_event_set_output(event, output_event);
4237 ret = perf_event_set_output(event, NULL);
4242 case PERF_EVENT_IOC_SET_FILTER:
4243 return perf_event_set_filter(event, (void __user *)arg);
4245 case PERF_EVENT_IOC_SET_BPF:
4246 return perf_event_set_bpf_prog(event, arg);
4252 if (flags & PERF_IOC_FLAG_GROUP)
4253 perf_event_for_each(event, func);
4255 perf_event_for_each_child(event, func);
4260 static long perf_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
4262 struct perf_event *event = file->private_data;
4263 struct perf_event_context *ctx;
4266 ctx = perf_event_ctx_lock(event);
4267 ret = _perf_ioctl(event, cmd, arg);
4268 perf_event_ctx_unlock(event, ctx);
4273 #ifdef CONFIG_COMPAT
4274 static long perf_compat_ioctl(struct file *file, unsigned int cmd,
4277 switch (_IOC_NR(cmd)) {
4278 case _IOC_NR(PERF_EVENT_IOC_SET_FILTER):
4279 case _IOC_NR(PERF_EVENT_IOC_ID):
4280 /* Fix up pointer size (usually 4 -> 8 in 32-on-64-bit case */
4281 if (_IOC_SIZE(cmd) == sizeof(compat_uptr_t)) {
4282 cmd &= ~IOCSIZE_MASK;
4283 cmd |= sizeof(void *) << IOCSIZE_SHIFT;
4287 return perf_ioctl(file, cmd, arg);
4290 # define perf_compat_ioctl NULL
4293 int perf_event_task_enable(void)
4295 struct perf_event_context *ctx;
4296 struct perf_event *event;
4298 mutex_lock(¤t->perf_event_mutex);
4299 list_for_each_entry(event, ¤t->perf_event_list, owner_entry) {
4300 ctx = perf_event_ctx_lock(event);
4301 perf_event_for_each_child(event, _perf_event_enable);
4302 perf_event_ctx_unlock(event, ctx);
4304 mutex_unlock(¤t->perf_event_mutex);
4309 int perf_event_task_disable(void)
4311 struct perf_event_context *ctx;
4312 struct perf_event *event;
4314 mutex_lock(¤t->perf_event_mutex);
4315 list_for_each_entry(event, ¤t->perf_event_list, owner_entry) {
4316 ctx = perf_event_ctx_lock(event);
4317 perf_event_for_each_child(event, _perf_event_disable);
4318 perf_event_ctx_unlock(event, ctx);
4320 mutex_unlock(¤t->perf_event_mutex);
4325 static int perf_event_index(struct perf_event *event)
4327 if (event->hw.state & PERF_HES_STOPPED)
4330 if (event->state != PERF_EVENT_STATE_ACTIVE)
4333 return event->pmu->event_idx(event);
4336 static void calc_timer_values(struct perf_event *event,
4343 *now = perf_clock();
4344 ctx_time = event->shadow_ctx_time + *now;
4345 *enabled = ctx_time - event->tstamp_enabled;
4346 *running = ctx_time - event->tstamp_running;
4349 static void perf_event_init_userpage(struct perf_event *event)
4351 struct perf_event_mmap_page *userpg;
4352 struct ring_buffer *rb;
4355 rb = rcu_dereference(event->rb);
4359 userpg = rb->user_page;
4361 /* Allow new userspace to detect that bit 0 is deprecated */
4362 userpg->cap_bit0_is_deprecated = 1;
4363 userpg->size = offsetof(struct perf_event_mmap_page, __reserved);
4364 userpg->data_offset = PAGE_SIZE;
4365 userpg->data_size = perf_data_size(rb);
4371 void __weak arch_perf_update_userpage(
4372 struct perf_event *event, struct perf_event_mmap_page *userpg, u64 now)
4377 * Callers need to ensure there can be no nesting of this function, otherwise
4378 * the seqlock logic goes bad. We can not serialize this because the arch
4379 * code calls this from NMI context.
4381 void perf_event_update_userpage(struct perf_event *event)
4383 struct perf_event_mmap_page *userpg;
4384 struct ring_buffer *rb;
4385 u64 enabled, running, now;
4388 rb = rcu_dereference(event->rb);
4393 * compute total_time_enabled, total_time_running
4394 * based on snapshot values taken when the event
4395 * was last scheduled in.
4397 * we cannot simply called update_context_time()
4398 * because of locking issue as we can be called in
4401 calc_timer_values(event, &now, &enabled, &running);
4403 userpg = rb->user_page;
4405 * Disable preemption so as to not let the corresponding user-space
4406 * spin too long if we get preempted.
4411 userpg->index = perf_event_index(event);
4412 userpg->offset = perf_event_count(event);
4414 userpg->offset -= local64_read(&event->hw.prev_count);
4416 userpg->time_enabled = enabled +
4417 atomic64_read(&event->child_total_time_enabled);
4419 userpg->time_running = running +
4420 atomic64_read(&event->child_total_time_running);
4422 arch_perf_update_userpage(event, userpg, now);
4431 static int perf_mmap_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
4433 struct perf_event *event = vma->vm_file->private_data;
4434 struct ring_buffer *rb;
4435 int ret = VM_FAULT_SIGBUS;
4437 if (vmf->flags & FAULT_FLAG_MKWRITE) {
4438 if (vmf->pgoff == 0)
4444 rb = rcu_dereference(event->rb);
4448 if (vmf->pgoff && (vmf->flags & FAULT_FLAG_WRITE))
4451 vmf->page = perf_mmap_to_page(rb, vmf->pgoff);
4455 get_page(vmf->page);
4456 vmf->page->mapping = vma->vm_file->f_mapping;
4457 vmf->page->index = vmf->pgoff;
4466 static void ring_buffer_attach(struct perf_event *event,
4467 struct ring_buffer *rb)
4469 struct ring_buffer *old_rb = NULL;
4470 unsigned long flags;
4474 * Should be impossible, we set this when removing
4475 * event->rb_entry and wait/clear when adding event->rb_entry.
4477 WARN_ON_ONCE(event->rcu_pending);
4480 spin_lock_irqsave(&old_rb->event_lock, flags);
4481 list_del_rcu(&event->rb_entry);
4482 spin_unlock_irqrestore(&old_rb->event_lock, flags);
4484 event->rcu_batches = get_state_synchronize_rcu();
4485 event->rcu_pending = 1;
4489 if (event->rcu_pending) {
4490 cond_synchronize_rcu(event->rcu_batches);
4491 event->rcu_pending = 0;
4494 spin_lock_irqsave(&rb->event_lock, flags);
4495 list_add_rcu(&event->rb_entry, &rb->event_list);
4496 spin_unlock_irqrestore(&rb->event_lock, flags);
4499 rcu_assign_pointer(event->rb, rb);
4502 ring_buffer_put(old_rb);
4504 * Since we detached before setting the new rb, so that we
4505 * could attach the new rb, we could have missed a wakeup.
4508 wake_up_all(&event->waitq);
4512 static void ring_buffer_wakeup(struct perf_event *event)
4514 struct ring_buffer *rb;
4517 rb = rcu_dereference(event->rb);
4519 list_for_each_entry_rcu(event, &rb->event_list, rb_entry)
4520 wake_up_all(&event->waitq);
4525 struct ring_buffer *ring_buffer_get(struct perf_event *event)
4527 struct ring_buffer *rb;
4530 rb = rcu_dereference(event->rb);
4532 if (!atomic_inc_not_zero(&rb->refcount))
4540 void ring_buffer_put(struct ring_buffer *rb)
4542 if (!atomic_dec_and_test(&rb->refcount))
4545 WARN_ON_ONCE(!list_empty(&rb->event_list));
4547 call_rcu(&rb->rcu_head, rb_free_rcu);
4550 static void perf_mmap_open(struct vm_area_struct *vma)
4552 struct perf_event *event = vma->vm_file->private_data;
4554 atomic_inc(&event->mmap_count);
4555 atomic_inc(&event->rb->mmap_count);
4558 atomic_inc(&event->rb->aux_mmap_count);
4560 if (event->pmu->event_mapped)
4561 event->pmu->event_mapped(event);
4565 * A buffer can be mmap()ed multiple times; either directly through the same
4566 * event, or through other events by use of perf_event_set_output().
4568 * In order to undo the VM accounting done by perf_mmap() we need to destroy
4569 * the buffer here, where we still have a VM context. This means we need
4570 * to detach all events redirecting to us.
4572 static void perf_mmap_close(struct vm_area_struct *vma)
4574 struct perf_event *event = vma->vm_file->private_data;
4576 struct ring_buffer *rb = ring_buffer_get(event);
4577 struct user_struct *mmap_user = rb->mmap_user;
4578 int mmap_locked = rb->mmap_locked;
4579 unsigned long size = perf_data_size(rb);
4581 if (event->pmu->event_unmapped)
4582 event->pmu->event_unmapped(event);
4585 * rb->aux_mmap_count will always drop before rb->mmap_count and
4586 * event->mmap_count, so it is ok to use event->mmap_mutex to
4587 * serialize with perf_mmap here.
4589 if (rb_has_aux(rb) && vma->vm_pgoff == rb->aux_pgoff &&
4590 atomic_dec_and_mutex_lock(&rb->aux_mmap_count, &event->mmap_mutex)) {
4591 atomic_long_sub(rb->aux_nr_pages, &mmap_user->locked_vm);
4592 vma->vm_mm->pinned_vm -= rb->aux_mmap_locked;
4595 mutex_unlock(&event->mmap_mutex);
4598 atomic_dec(&rb->mmap_count);
4600 if (!atomic_dec_and_mutex_lock(&event->mmap_count, &event->mmap_mutex))
4603 ring_buffer_attach(event, NULL);
4604 mutex_unlock(&event->mmap_mutex);
4606 /* If there's still other mmap()s of this buffer, we're done. */
4607 if (atomic_read(&rb->mmap_count))
4611 * No other mmap()s, detach from all other events that might redirect
4612 * into the now unreachable buffer. Somewhat complicated by the
4613 * fact that rb::event_lock otherwise nests inside mmap_mutex.
4617 list_for_each_entry_rcu(event, &rb->event_list, rb_entry) {
4618 if (!atomic_long_inc_not_zero(&event->refcount)) {
4620 * This event is en-route to free_event() which will
4621 * detach it and remove it from the list.
4627 mutex_lock(&event->mmap_mutex);
4629 * Check we didn't race with perf_event_set_output() which can
4630 * swizzle the rb from under us while we were waiting to
4631 * acquire mmap_mutex.
4633 * If we find a different rb; ignore this event, a next
4634 * iteration will no longer find it on the list. We have to
4635 * still restart the iteration to make sure we're not now
4636 * iterating the wrong list.
4638 if (event->rb == rb)
4639 ring_buffer_attach(event, NULL);
4641 mutex_unlock(&event->mmap_mutex);
4645 * Restart the iteration; either we're on the wrong list or
4646 * destroyed its integrity by doing a deletion.
4653 * It could be there's still a few 0-ref events on the list; they'll
4654 * get cleaned up by free_event() -- they'll also still have their
4655 * ref on the rb and will free it whenever they are done with it.
4657 * Aside from that, this buffer is 'fully' detached and unmapped,
4658 * undo the VM accounting.
4661 atomic_long_sub((size >> PAGE_SHIFT) + 1, &mmap_user->locked_vm);
4662 vma->vm_mm->pinned_vm -= mmap_locked;
4663 free_uid(mmap_user);
4666 ring_buffer_put(rb); /* could be last */
4669 static const struct vm_operations_struct perf_mmap_vmops = {
4670 .open = perf_mmap_open,
4671 .close = perf_mmap_close, /* non mergable */
4672 .fault = perf_mmap_fault,
4673 .page_mkwrite = perf_mmap_fault,
4676 static int perf_mmap(struct file *file, struct vm_area_struct *vma)
4678 struct perf_event *event = file->private_data;
4679 unsigned long user_locked, user_lock_limit;
4680 struct user_struct *user = current_user();
4681 unsigned long locked, lock_limit;
4682 struct ring_buffer *rb = NULL;
4683 unsigned long vma_size;
4684 unsigned long nr_pages;
4685 long user_extra = 0, extra = 0;
4686 int ret = 0, flags = 0;
4689 * Don't allow mmap() of inherited per-task counters. This would
4690 * create a performance issue due to all children writing to the
4693 if (event->cpu == -1 && event->attr.inherit)
4696 if (!(vma->vm_flags & VM_SHARED))
4699 vma_size = vma->vm_end - vma->vm_start;
4701 if (vma->vm_pgoff == 0) {
4702 nr_pages = (vma_size / PAGE_SIZE) - 1;
4705 * AUX area mapping: if rb->aux_nr_pages != 0, it's already
4706 * mapped, all subsequent mappings should have the same size
4707 * and offset. Must be above the normal perf buffer.
4709 u64 aux_offset, aux_size;
4714 nr_pages = vma_size / PAGE_SIZE;
4716 mutex_lock(&event->mmap_mutex);
4723 aux_offset = ACCESS_ONCE(rb->user_page->aux_offset);
4724 aux_size = ACCESS_ONCE(rb->user_page->aux_size);
4726 if (aux_offset < perf_data_size(rb) + PAGE_SIZE)
4729 if (aux_offset != vma->vm_pgoff << PAGE_SHIFT)
4732 /* already mapped with a different offset */
4733 if (rb_has_aux(rb) && rb->aux_pgoff != vma->vm_pgoff)
4736 if (aux_size != vma_size || aux_size != nr_pages * PAGE_SIZE)
4739 /* already mapped with a different size */
4740 if (rb_has_aux(rb) && rb->aux_nr_pages != nr_pages)
4743 if (!is_power_of_2(nr_pages))
4746 if (!atomic_inc_not_zero(&rb->mmap_count))
4749 if (rb_has_aux(rb)) {
4750 atomic_inc(&rb->aux_mmap_count);
4755 atomic_set(&rb->aux_mmap_count, 1);
4756 user_extra = nr_pages;
4762 * If we have rb pages ensure they're a power-of-two number, so we
4763 * can do bitmasks instead of modulo.
4765 if (nr_pages != 0 && !is_power_of_2(nr_pages))
4768 if (vma_size != PAGE_SIZE * (1 + nr_pages))
4771 WARN_ON_ONCE(event->ctx->parent_ctx);
4773 mutex_lock(&event->mmap_mutex);
4775 if (event->rb->nr_pages != nr_pages) {
4780 if (!atomic_inc_not_zero(&event->rb->mmap_count)) {
4782 * Raced against perf_mmap_close() through
4783 * perf_event_set_output(). Try again, hope for better
4786 mutex_unlock(&event->mmap_mutex);
4793 user_extra = nr_pages + 1;
4796 user_lock_limit = sysctl_perf_event_mlock >> (PAGE_SHIFT - 10);
4799 * Increase the limit linearly with more CPUs:
4801 user_lock_limit *= num_online_cpus();
4803 user_locked = atomic_long_read(&user->locked_vm) + user_extra;
4805 if (user_locked > user_lock_limit)
4806 extra = user_locked - user_lock_limit;
4808 lock_limit = rlimit(RLIMIT_MEMLOCK);
4809 lock_limit >>= PAGE_SHIFT;
4810 locked = vma->vm_mm->pinned_vm + extra;
4812 if ((locked > lock_limit) && perf_paranoid_tracepoint_raw() &&
4813 !capable(CAP_IPC_LOCK)) {
4818 WARN_ON(!rb && event->rb);
4820 if (vma->vm_flags & VM_WRITE)
4821 flags |= RING_BUFFER_WRITABLE;
4824 rb = rb_alloc(nr_pages,
4825 event->attr.watermark ? event->attr.wakeup_watermark : 0,
4833 atomic_set(&rb->mmap_count, 1);
4834 rb->mmap_user = get_current_user();
4835 rb->mmap_locked = extra;
4837 ring_buffer_attach(event, rb);
4839 perf_event_init_userpage(event);
4840 perf_event_update_userpage(event);
4842 ret = rb_alloc_aux(rb, event, vma->vm_pgoff, nr_pages,
4843 event->attr.aux_watermark, flags);
4845 rb->aux_mmap_locked = extra;
4850 atomic_long_add(user_extra, &user->locked_vm);
4851 vma->vm_mm->pinned_vm += extra;
4853 atomic_inc(&event->mmap_count);
4855 atomic_dec(&rb->mmap_count);
4858 mutex_unlock(&event->mmap_mutex);
4861 * Since pinned accounting is per vm we cannot allow fork() to copy our
4864 vma->vm_flags |= VM_DONTCOPY | VM_DONTEXPAND | VM_DONTDUMP;
4865 vma->vm_ops = &perf_mmap_vmops;
4867 if (event->pmu->event_mapped)
4868 event->pmu->event_mapped(event);
4873 static int perf_fasync(int fd, struct file *filp, int on)
4875 struct inode *inode = file_inode(filp);
4876 struct perf_event *event = filp->private_data;
4879 mutex_lock(&inode->i_mutex);
4880 retval = fasync_helper(fd, filp, on, &event->fasync);
4881 mutex_unlock(&inode->i_mutex);
4889 static const struct file_operations perf_fops = {
4890 .llseek = no_llseek,
4891 .release = perf_release,
4894 .unlocked_ioctl = perf_ioctl,
4895 .compat_ioctl = perf_compat_ioctl,
4897 .fasync = perf_fasync,
4903 * If there's data, ensure we set the poll() state and publish everything
4904 * to user-space before waking everybody up.
4907 static inline struct fasync_struct **perf_event_fasync(struct perf_event *event)
4909 /* only the parent has fasync state */
4911 event = event->parent;
4912 return &event->fasync;
4915 void perf_event_wakeup(struct perf_event *event)
4917 ring_buffer_wakeup(event);
4919 if (event->pending_kill) {
4920 kill_fasync(perf_event_fasync(event), SIGIO, event->pending_kill);
4921 event->pending_kill = 0;
4925 static void perf_pending_event(struct irq_work *entry)
4927 struct perf_event *event = container_of(entry,
4928 struct perf_event, pending);
4931 rctx = perf_swevent_get_recursion_context();
4933 * If we 'fail' here, that's OK, it means recursion is already disabled
4934 * and we won't recurse 'further'.
4937 if (event->pending_disable) {
4938 event->pending_disable = 0;
4939 perf_event_disable_local(event);
4942 if (event->pending_wakeup) {
4943 event->pending_wakeup = 0;
4944 perf_event_wakeup(event);
4948 perf_swevent_put_recursion_context(rctx);
4952 * We assume there is only KVM supporting the callbacks.
4953 * Later on, we might change it to a list if there is
4954 * another virtualization implementation supporting the callbacks.
4956 struct perf_guest_info_callbacks *perf_guest_cbs;
4958 int perf_register_guest_info_callbacks(struct perf_guest_info_callbacks *cbs)
4960 perf_guest_cbs = cbs;
4963 EXPORT_SYMBOL_GPL(perf_register_guest_info_callbacks);
4965 int perf_unregister_guest_info_callbacks(struct perf_guest_info_callbacks *cbs)
4967 perf_guest_cbs = NULL;
4970 EXPORT_SYMBOL_GPL(perf_unregister_guest_info_callbacks);
4973 perf_output_sample_regs(struct perf_output_handle *handle,
4974 struct pt_regs *regs, u64 mask)
4978 for_each_set_bit(bit, (const unsigned long *) &mask,
4979 sizeof(mask) * BITS_PER_BYTE) {
4982 val = perf_reg_value(regs, bit);
4983 perf_output_put(handle, val);
4987 static void perf_sample_regs_user(struct perf_regs *regs_user,
4988 struct pt_regs *regs,
4989 struct pt_regs *regs_user_copy)
4991 if (user_mode(regs)) {
4992 regs_user->abi = perf_reg_abi(current);
4993 regs_user->regs = regs;
4994 } else if (current->mm) {
4995 perf_get_regs_user(regs_user, regs, regs_user_copy);
4997 regs_user->abi = PERF_SAMPLE_REGS_ABI_NONE;
4998 regs_user->regs = NULL;
5002 static void perf_sample_regs_intr(struct perf_regs *regs_intr,
5003 struct pt_regs *regs)
5005 regs_intr->regs = regs;
5006 regs_intr->abi = perf_reg_abi(current);
5011 * Get remaining task size from user stack pointer.
5013 * It'd be better to take stack vma map and limit this more
5014 * precisly, but there's no way to get it safely under interrupt,
5015 * so using TASK_SIZE as limit.
5017 static u64 perf_ustack_task_size(struct pt_regs *regs)
5019 unsigned long addr = perf_user_stack_pointer(regs);
5021 if (!addr || addr >= TASK_SIZE)
5024 return TASK_SIZE - addr;
5028 perf_sample_ustack_size(u16 stack_size, u16 header_size,
5029 struct pt_regs *regs)
5033 /* No regs, no stack pointer, no dump. */
5038 * Check if we fit in with the requested stack size into the:
5040 * If we don't, we limit the size to the TASK_SIZE.
5042 * - remaining sample size
5043 * If we don't, we customize the stack size to
5044 * fit in to the remaining sample size.
5047 task_size = min((u64) USHRT_MAX, perf_ustack_task_size(regs));
5048 stack_size = min(stack_size, (u16) task_size);
5050 /* Current header size plus static size and dynamic size. */
5051 header_size += 2 * sizeof(u64);
5053 /* Do we fit in with the current stack dump size? */
5054 if ((u16) (header_size + stack_size) < header_size) {
5056 * If we overflow the maximum size for the sample,
5057 * we customize the stack dump size to fit in.
5059 stack_size = USHRT_MAX - header_size - sizeof(u64);
5060 stack_size = round_up(stack_size, sizeof(u64));
5067 perf_output_sample_ustack(struct perf_output_handle *handle, u64 dump_size,
5068 struct pt_regs *regs)
5070 /* Case of a kernel thread, nothing to dump */
5073 perf_output_put(handle, size);
5082 * - the size requested by user or the best one we can fit
5083 * in to the sample max size
5085 * - user stack dump data
5087 * - the actual dumped size
5091 perf_output_put(handle, dump_size);
5094 sp = perf_user_stack_pointer(regs);
5095 rem = __output_copy_user(handle, (void *) sp, dump_size);
5096 dyn_size = dump_size - rem;
5098 perf_output_skip(handle, rem);
5101 perf_output_put(handle, dyn_size);
5105 static void __perf_event_header__init_id(struct perf_event_header *header,
5106 struct perf_sample_data *data,
5107 struct perf_event *event)
5109 u64 sample_type = event->attr.sample_type;
5111 data->type = sample_type;
5112 header->size += event->id_header_size;
5114 if (sample_type & PERF_SAMPLE_TID) {
5115 /* namespace issues */
5116 data->tid_entry.pid = perf_event_pid(event, current);
5117 data->tid_entry.tid = perf_event_tid(event, current);
5120 if (sample_type & PERF_SAMPLE_TIME)
5121 data->time = perf_event_clock(event);
5123 if (sample_type & (PERF_SAMPLE_ID | PERF_SAMPLE_IDENTIFIER))
5124 data->id = primary_event_id(event);
5126 if (sample_type & PERF_SAMPLE_STREAM_ID)
5127 data->stream_id = event->id;
5129 if (sample_type & PERF_SAMPLE_CPU) {
5130 data->cpu_entry.cpu = raw_smp_processor_id();
5131 data->cpu_entry.reserved = 0;
5135 void perf_event_header__init_id(struct perf_event_header *header,
5136 struct perf_sample_data *data,
5137 struct perf_event *event)
5139 if (event->attr.sample_id_all)
5140 __perf_event_header__init_id(header, data, event);
5143 static void __perf_event__output_id_sample(struct perf_output_handle *handle,
5144 struct perf_sample_data *data)
5146 u64 sample_type = data->type;
5148 if (sample_type & PERF_SAMPLE_TID)
5149 perf_output_put(handle, data->tid_entry);
5151 if (sample_type & PERF_SAMPLE_TIME)
5152 perf_output_put(handle, data->time);
5154 if (sample_type & PERF_SAMPLE_ID)
5155 perf_output_put(handle, data->id);
5157 if (sample_type & PERF_SAMPLE_STREAM_ID)
5158 perf_output_put(handle, data->stream_id);
5160 if (sample_type & PERF_SAMPLE_CPU)
5161 perf_output_put(handle, data->cpu_entry);
5163 if (sample_type & PERF_SAMPLE_IDENTIFIER)
5164 perf_output_put(handle, data->id);
5167 void perf_event__output_id_sample(struct perf_event *event,
5168 struct perf_output_handle *handle,
5169 struct perf_sample_data *sample)
5171 if (event->attr.sample_id_all)
5172 __perf_event__output_id_sample(handle, sample);
5175 static void perf_output_read_one(struct perf_output_handle *handle,
5176 struct perf_event *event,
5177 u64 enabled, u64 running)
5179 u64 read_format = event->attr.read_format;
5183 values[n++] = perf_event_count(event);
5184 if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED) {
5185 values[n++] = enabled +
5186 atomic64_read(&event->child_total_time_enabled);
5188 if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING) {
5189 values[n++] = running +
5190 atomic64_read(&event->child_total_time_running);
5192 if (read_format & PERF_FORMAT_ID)
5193 values[n++] = primary_event_id(event);
5195 __output_copy(handle, values, n * sizeof(u64));
5199 * XXX PERF_FORMAT_GROUP vs inherited events seems difficult.
5201 static void perf_output_read_group(struct perf_output_handle *handle,
5202 struct perf_event *event,
5203 u64 enabled, u64 running)
5205 struct perf_event *leader = event->group_leader, *sub;
5206 u64 read_format = event->attr.read_format;
5210 values[n++] = 1 + leader->nr_siblings;
5212 if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED)
5213 values[n++] = enabled;
5215 if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING)
5216 values[n++] = running;
5218 if (leader != event)
5219 leader->pmu->read(leader);
5221 values[n++] = perf_event_count(leader);
5222 if (read_format & PERF_FORMAT_ID)
5223 values[n++] = primary_event_id(leader);
5225 __output_copy(handle, values, n * sizeof(u64));
5227 list_for_each_entry(sub, &leader->sibling_list, group_entry) {
5230 if ((sub != event) &&
5231 (sub->state == PERF_EVENT_STATE_ACTIVE))
5232 sub->pmu->read(sub);
5234 values[n++] = perf_event_count(sub);
5235 if (read_format & PERF_FORMAT_ID)
5236 values[n++] = primary_event_id(sub);
5238 __output_copy(handle, values, n * sizeof(u64));
5242 #define PERF_FORMAT_TOTAL_TIMES (PERF_FORMAT_TOTAL_TIME_ENABLED|\
5243 PERF_FORMAT_TOTAL_TIME_RUNNING)
5245 static void perf_output_read(struct perf_output_handle *handle,
5246 struct perf_event *event)
5248 u64 enabled = 0, running = 0, now;
5249 u64 read_format = event->attr.read_format;
5252 * compute total_time_enabled, total_time_running
5253 * based on snapshot values taken when the event
5254 * was last scheduled in.
5256 * we cannot simply called update_context_time()
5257 * because of locking issue as we are called in
5260 if (read_format & PERF_FORMAT_TOTAL_TIMES)
5261 calc_timer_values(event, &now, &enabled, &running);
5263 if (event->attr.read_format & PERF_FORMAT_GROUP)
5264 perf_output_read_group(handle, event, enabled, running);
5266 perf_output_read_one(handle, event, enabled, running);
5269 void perf_output_sample(struct perf_output_handle *handle,
5270 struct perf_event_header *header,
5271 struct perf_sample_data *data,
5272 struct perf_event *event)
5274 u64 sample_type = data->type;
5276 perf_output_put(handle, *header);
5278 if (sample_type & PERF_SAMPLE_IDENTIFIER)
5279 perf_output_put(handle, data->id);
5281 if (sample_type & PERF_SAMPLE_IP)
5282 perf_output_put(handle, data->ip);
5284 if (sample_type & PERF_SAMPLE_TID)
5285 perf_output_put(handle, data->tid_entry);
5287 if (sample_type & PERF_SAMPLE_TIME)
5288 perf_output_put(handle, data->time);
5290 if (sample_type & PERF_SAMPLE_ADDR)
5291 perf_output_put(handle, data->addr);
5293 if (sample_type & PERF_SAMPLE_ID)
5294 perf_output_put(handle, data->id);
5296 if (sample_type & PERF_SAMPLE_STREAM_ID)
5297 perf_output_put(handle, data->stream_id);
5299 if (sample_type & PERF_SAMPLE_CPU)
5300 perf_output_put(handle, data->cpu_entry);
5302 if (sample_type & PERF_SAMPLE_PERIOD)
5303 perf_output_put(handle, data->period);
5305 if (sample_type & PERF_SAMPLE_READ)
5306 perf_output_read(handle, event);
5308 if (sample_type & PERF_SAMPLE_CALLCHAIN) {
5309 if (data->callchain) {
5312 if (data->callchain)
5313 size += data->callchain->nr;
5315 size *= sizeof(u64);
5317 __output_copy(handle, data->callchain, size);
5320 perf_output_put(handle, nr);
5324 if (sample_type & PERF_SAMPLE_RAW) {
5326 u32 raw_size = data->raw->size;
5327 u32 real_size = round_up(raw_size + sizeof(u32),
5328 sizeof(u64)) - sizeof(u32);
5331 perf_output_put(handle, real_size);
5332 __output_copy(handle, data->raw->data, raw_size);
5333 if (real_size - raw_size)
5334 __output_copy(handle, &zero, real_size - raw_size);
5340 .size = sizeof(u32),
5343 perf_output_put(handle, raw);
5347 if (sample_type & PERF_SAMPLE_BRANCH_STACK) {
5348 if (data->br_stack) {
5351 size = data->br_stack->nr
5352 * sizeof(struct perf_branch_entry);
5354 perf_output_put(handle, data->br_stack->nr);
5355 perf_output_copy(handle, data->br_stack->entries, size);
5358 * we always store at least the value of nr
5361 perf_output_put(handle, nr);
5365 if (sample_type & PERF_SAMPLE_REGS_USER) {
5366 u64 abi = data->regs_user.abi;
5369 * If there are no regs to dump, notice it through
5370 * first u64 being zero (PERF_SAMPLE_REGS_ABI_NONE).
5372 perf_output_put(handle, abi);
5375 u64 mask = event->attr.sample_regs_user;
5376 perf_output_sample_regs(handle,
5377 data->regs_user.regs,
5382 if (sample_type & PERF_SAMPLE_STACK_USER) {
5383 perf_output_sample_ustack(handle,
5384 data->stack_user_size,
5385 data->regs_user.regs);
5388 if (sample_type & PERF_SAMPLE_WEIGHT)
5389 perf_output_put(handle, data->weight);
5391 if (sample_type & PERF_SAMPLE_DATA_SRC)
5392 perf_output_put(handle, data->data_src.val);
5394 if (sample_type & PERF_SAMPLE_TRANSACTION)
5395 perf_output_put(handle, data->txn);
5397 if (sample_type & PERF_SAMPLE_REGS_INTR) {
5398 u64 abi = data->regs_intr.abi;
5400 * If there are no regs to dump, notice it through
5401 * first u64 being zero (PERF_SAMPLE_REGS_ABI_NONE).
5403 perf_output_put(handle, abi);
5406 u64 mask = event->attr.sample_regs_intr;
5408 perf_output_sample_regs(handle,
5409 data->regs_intr.regs,
5414 if (!event->attr.watermark) {
5415 int wakeup_events = event->attr.wakeup_events;
5417 if (wakeup_events) {
5418 struct ring_buffer *rb = handle->rb;
5419 int events = local_inc_return(&rb->events);
5421 if (events >= wakeup_events) {
5422 local_sub(wakeup_events, &rb->events);
5423 local_inc(&rb->wakeup);
5429 void perf_prepare_sample(struct perf_event_header *header,
5430 struct perf_sample_data *data,
5431 struct perf_event *event,
5432 struct pt_regs *regs)
5434 u64 sample_type = event->attr.sample_type;
5436 header->type = PERF_RECORD_SAMPLE;
5437 header->size = sizeof(*header) + event->header_size;
5440 header->misc |= perf_misc_flags(regs);
5442 __perf_event_header__init_id(header, data, event);
5444 if (sample_type & PERF_SAMPLE_IP)
5445 data->ip = perf_instruction_pointer(regs);
5447 if (sample_type & PERF_SAMPLE_CALLCHAIN) {
5450 data->callchain = perf_callchain(event, regs);
5452 if (data->callchain)
5453 size += data->callchain->nr;
5455 header->size += size * sizeof(u64);
5458 if (sample_type & PERF_SAMPLE_RAW) {
5459 int size = sizeof(u32);
5462 size += data->raw->size;
5464 size += sizeof(u32);
5466 header->size += round_up(size, sizeof(u64));
5469 if (sample_type & PERF_SAMPLE_BRANCH_STACK) {
5470 int size = sizeof(u64); /* nr */
5471 if (data->br_stack) {
5472 size += data->br_stack->nr
5473 * sizeof(struct perf_branch_entry);
5475 header->size += size;
5478 if (sample_type & (PERF_SAMPLE_REGS_USER | PERF_SAMPLE_STACK_USER))
5479 perf_sample_regs_user(&data->regs_user, regs,
5480 &data->regs_user_copy);
5482 if (sample_type & PERF_SAMPLE_REGS_USER) {
5483 /* regs dump ABI info */
5484 int size = sizeof(u64);
5486 if (data->regs_user.regs) {
5487 u64 mask = event->attr.sample_regs_user;
5488 size += hweight64(mask) * sizeof(u64);
5491 header->size += size;
5494 if (sample_type & PERF_SAMPLE_STACK_USER) {
5496 * Either we need PERF_SAMPLE_STACK_USER bit to be allways
5497 * processed as the last one or have additional check added
5498 * in case new sample type is added, because we could eat
5499 * up the rest of the sample size.
5501 u16 stack_size = event->attr.sample_stack_user;
5502 u16 size = sizeof(u64);
5504 stack_size = perf_sample_ustack_size(stack_size, header->size,
5505 data->regs_user.regs);
5508 * If there is something to dump, add space for the dump
5509 * itself and for the field that tells the dynamic size,
5510 * which is how many have been actually dumped.
5513 size += sizeof(u64) + stack_size;
5515 data->stack_user_size = stack_size;
5516 header->size += size;
5519 if (sample_type & PERF_SAMPLE_REGS_INTR) {
5520 /* regs dump ABI info */
5521 int size = sizeof(u64);
5523 perf_sample_regs_intr(&data->regs_intr, regs);
5525 if (data->regs_intr.regs) {
5526 u64 mask = event->attr.sample_regs_intr;
5528 size += hweight64(mask) * sizeof(u64);
5531 header->size += size;
5535 void perf_event_output(struct perf_event *event,
5536 struct perf_sample_data *data,
5537 struct pt_regs *regs)
5539 struct perf_output_handle handle;
5540 struct perf_event_header header;
5542 /* protect the callchain buffers */
5545 perf_prepare_sample(&header, data, event, regs);
5547 if (perf_output_begin(&handle, event, header.size))
5550 perf_output_sample(&handle, &header, data, event);
5552 perf_output_end(&handle);
5562 struct perf_read_event {
5563 struct perf_event_header header;
5570 perf_event_read_event(struct perf_event *event,
5571 struct task_struct *task)
5573 struct perf_output_handle handle;
5574 struct perf_sample_data sample;
5575 struct perf_read_event read_event = {
5577 .type = PERF_RECORD_READ,
5579 .size = sizeof(read_event) + event->read_size,
5581 .pid = perf_event_pid(event, task),
5582 .tid = perf_event_tid(event, task),
5586 perf_event_header__init_id(&read_event.header, &sample, event);
5587 ret = perf_output_begin(&handle, event, read_event.header.size);
5591 perf_output_put(&handle, read_event);
5592 perf_output_read(&handle, event);
5593 perf_event__output_id_sample(event, &handle, &sample);
5595 perf_output_end(&handle);
5598 typedef void (perf_event_aux_output_cb)(struct perf_event *event, void *data);
5601 perf_event_aux_ctx(struct perf_event_context *ctx,
5602 perf_event_aux_output_cb output,
5605 struct perf_event *event;
5607 list_for_each_entry_rcu(event, &ctx->event_list, event_entry) {
5608 if (event->state < PERF_EVENT_STATE_INACTIVE)
5610 if (!event_filter_match(event))
5612 output(event, data);
5617 perf_event_aux_task_ctx(perf_event_aux_output_cb output, void *data,
5618 struct perf_event_context *task_ctx)
5622 perf_event_aux_ctx(task_ctx, output, data);
5628 perf_event_aux(perf_event_aux_output_cb output, void *data,
5629 struct perf_event_context *task_ctx)
5631 struct perf_cpu_context *cpuctx;
5632 struct perf_event_context *ctx;
5637 * If we have task_ctx != NULL we only notify
5638 * the task context itself. The task_ctx is set
5639 * only for EXIT events before releasing task
5643 perf_event_aux_task_ctx(output, data, task_ctx);
5648 list_for_each_entry_rcu(pmu, &pmus, entry) {
5649 cpuctx = get_cpu_ptr(pmu->pmu_cpu_context);
5650 if (cpuctx->unique_pmu != pmu)
5652 perf_event_aux_ctx(&cpuctx->ctx, output, data);
5653 ctxn = pmu->task_ctx_nr;
5656 ctx = rcu_dereference(current->perf_event_ctxp[ctxn]);
5658 perf_event_aux_ctx(ctx, output, data);
5660 put_cpu_ptr(pmu->pmu_cpu_context);
5666 * task tracking -- fork/exit
5668 * enabled by: attr.comm | attr.mmap | attr.mmap2 | attr.mmap_data | attr.task
5671 struct perf_task_event {
5672 struct task_struct *task;
5673 struct perf_event_context *task_ctx;
5676 struct perf_event_header header;
5686 static int perf_event_task_match(struct perf_event *event)
5688 return event->attr.comm || event->attr.mmap ||
5689 event->attr.mmap2 || event->attr.mmap_data ||
5693 static void perf_event_task_output(struct perf_event *event,
5696 struct perf_task_event *task_event = data;
5697 struct perf_output_handle handle;
5698 struct perf_sample_data sample;
5699 struct task_struct *task = task_event->task;
5700 int ret, size = task_event->event_id.header.size;
5702 if (!perf_event_task_match(event))
5705 perf_event_header__init_id(&task_event->event_id.header, &sample, event);
5707 ret = perf_output_begin(&handle, event,
5708 task_event->event_id.header.size);
5712 task_event->event_id.pid = perf_event_pid(event, task);
5713 task_event->event_id.ppid = perf_event_pid(event, current);
5715 task_event->event_id.tid = perf_event_tid(event, task);
5716 task_event->event_id.ptid = perf_event_tid(event, current);
5718 task_event->event_id.time = perf_event_clock(event);
5720 perf_output_put(&handle, task_event->event_id);
5722 perf_event__output_id_sample(event, &handle, &sample);
5724 perf_output_end(&handle);
5726 task_event->event_id.header.size = size;
5729 static void perf_event_task(struct task_struct *task,
5730 struct perf_event_context *task_ctx,
5733 struct perf_task_event task_event;
5735 if (!atomic_read(&nr_comm_events) &&
5736 !atomic_read(&nr_mmap_events) &&
5737 !atomic_read(&nr_task_events))
5740 task_event = (struct perf_task_event){
5742 .task_ctx = task_ctx,
5745 .type = new ? PERF_RECORD_FORK : PERF_RECORD_EXIT,
5747 .size = sizeof(task_event.event_id),
5757 perf_event_aux(perf_event_task_output,
5762 void perf_event_fork(struct task_struct *task)
5764 perf_event_task(task, NULL, 1);
5771 struct perf_comm_event {
5772 struct task_struct *task;
5777 struct perf_event_header header;
5784 static int perf_event_comm_match(struct perf_event *event)
5786 return event->attr.comm;
5789 static void perf_event_comm_output(struct perf_event *event,
5792 struct perf_comm_event *comm_event = data;
5793 struct perf_output_handle handle;
5794 struct perf_sample_data sample;
5795 int size = comm_event->event_id.header.size;
5798 if (!perf_event_comm_match(event))
5801 perf_event_header__init_id(&comm_event->event_id.header, &sample, event);
5802 ret = perf_output_begin(&handle, event,
5803 comm_event->event_id.header.size);
5808 comm_event->event_id.pid = perf_event_pid(event, comm_event->task);
5809 comm_event->event_id.tid = perf_event_tid(event, comm_event->task);
5811 perf_output_put(&handle, comm_event->event_id);
5812 __output_copy(&handle, comm_event->comm,
5813 comm_event->comm_size);
5815 perf_event__output_id_sample(event, &handle, &sample);
5817 perf_output_end(&handle);
5819 comm_event->event_id.header.size = size;
5822 static void perf_event_comm_event(struct perf_comm_event *comm_event)
5824 char comm[TASK_COMM_LEN];
5827 memset(comm, 0, sizeof(comm));
5828 strlcpy(comm, comm_event->task->comm, sizeof(comm));
5829 size = ALIGN(strlen(comm)+1, sizeof(u64));
5831 comm_event->comm = comm;
5832 comm_event->comm_size = size;
5834 comm_event->event_id.header.size = sizeof(comm_event->event_id) + size;
5836 perf_event_aux(perf_event_comm_output,
5841 void perf_event_comm(struct task_struct *task, bool exec)
5843 struct perf_comm_event comm_event;
5845 if (!atomic_read(&nr_comm_events))
5848 comm_event = (struct perf_comm_event){
5854 .type = PERF_RECORD_COMM,
5855 .misc = exec ? PERF_RECORD_MISC_COMM_EXEC : 0,
5863 perf_event_comm_event(&comm_event);
5870 struct perf_mmap_event {
5871 struct vm_area_struct *vma;
5873 const char *file_name;
5881 struct perf_event_header header;
5891 static int perf_event_mmap_match(struct perf_event *event,
5894 struct perf_mmap_event *mmap_event = data;
5895 struct vm_area_struct *vma = mmap_event->vma;
5896 int executable = vma->vm_flags & VM_EXEC;
5898 return (!executable && event->attr.mmap_data) ||
5899 (executable && (event->attr.mmap || event->attr.mmap2));
5902 static void perf_event_mmap_output(struct perf_event *event,
5905 struct perf_mmap_event *mmap_event = data;
5906 struct perf_output_handle handle;
5907 struct perf_sample_data sample;
5908 int size = mmap_event->event_id.header.size;
5911 if (!perf_event_mmap_match(event, data))
5914 if (event->attr.mmap2) {
5915 mmap_event->event_id.header.type = PERF_RECORD_MMAP2;
5916 mmap_event->event_id.header.size += sizeof(mmap_event->maj);
5917 mmap_event->event_id.header.size += sizeof(mmap_event->min);
5918 mmap_event->event_id.header.size += sizeof(mmap_event->ino);
5919 mmap_event->event_id.header.size += sizeof(mmap_event->ino_generation);
5920 mmap_event->event_id.header.size += sizeof(mmap_event->prot);
5921 mmap_event->event_id.header.size += sizeof(mmap_event->flags);
5924 perf_event_header__init_id(&mmap_event->event_id.header, &sample, event);
5925 ret = perf_output_begin(&handle, event,
5926 mmap_event->event_id.header.size);
5930 mmap_event->event_id.pid = perf_event_pid(event, current);
5931 mmap_event->event_id.tid = perf_event_tid(event, current);
5933 perf_output_put(&handle, mmap_event->event_id);
5935 if (event->attr.mmap2) {
5936 perf_output_put(&handle, mmap_event->maj);
5937 perf_output_put(&handle, mmap_event->min);
5938 perf_output_put(&handle, mmap_event->ino);
5939 perf_output_put(&handle, mmap_event->ino_generation);
5940 perf_output_put(&handle, mmap_event->prot);
5941 perf_output_put(&handle, mmap_event->flags);
5944 __output_copy(&handle, mmap_event->file_name,
5945 mmap_event->file_size);
5947 perf_event__output_id_sample(event, &handle, &sample);
5949 perf_output_end(&handle);
5951 mmap_event->event_id.header.size = size;
5954 static void perf_event_mmap_event(struct perf_mmap_event *mmap_event)
5956 struct vm_area_struct *vma = mmap_event->vma;
5957 struct file *file = vma->vm_file;
5958 int maj = 0, min = 0;
5959 u64 ino = 0, gen = 0;
5960 u32 prot = 0, flags = 0;
5967 struct inode *inode;
5970 buf = kmalloc(PATH_MAX, GFP_KERNEL);
5976 * d_path() works from the end of the rb backwards, so we
5977 * need to add enough zero bytes after the string to handle
5978 * the 64bit alignment we do later.
5980 name = file_path(file, buf, PATH_MAX - sizeof(u64));
5985 inode = file_inode(vma->vm_file);
5986 dev = inode->i_sb->s_dev;
5988 gen = inode->i_generation;
5992 if (vma->vm_flags & VM_READ)
5994 if (vma->vm_flags & VM_WRITE)
5996 if (vma->vm_flags & VM_EXEC)
5999 if (vma->vm_flags & VM_MAYSHARE)
6002 flags = MAP_PRIVATE;
6004 if (vma->vm_flags & VM_DENYWRITE)
6005 flags |= MAP_DENYWRITE;
6006 if (vma->vm_flags & VM_MAYEXEC)
6007 flags |= MAP_EXECUTABLE;
6008 if (vma->vm_flags & VM_LOCKED)
6009 flags |= MAP_LOCKED;
6010 if (vma->vm_flags & VM_HUGETLB)
6011 flags |= MAP_HUGETLB;
6015 if (vma->vm_ops && vma->vm_ops->name) {
6016 name = (char *) vma->vm_ops->name(vma);
6021 name = (char *)arch_vma_name(vma);
6025 if (vma->vm_start <= vma->vm_mm->start_brk &&
6026 vma->vm_end >= vma->vm_mm->brk) {
6030 if (vma->vm_start <= vma->vm_mm->start_stack &&
6031 vma->vm_end >= vma->vm_mm->start_stack) {
6041 strlcpy(tmp, name, sizeof(tmp));
6045 * Since our buffer works in 8 byte units we need to align our string
6046 * size to a multiple of 8. However, we must guarantee the tail end is
6047 * zero'd out to avoid leaking random bits to userspace.
6049 size = strlen(name)+1;
6050 while (!IS_ALIGNED(size, sizeof(u64)))
6051 name[size++] = '\0';
6053 mmap_event->file_name = name;
6054 mmap_event->file_size = size;
6055 mmap_event->maj = maj;
6056 mmap_event->min = min;
6057 mmap_event->ino = ino;
6058 mmap_event->ino_generation = gen;
6059 mmap_event->prot = prot;
6060 mmap_event->flags = flags;
6062 if (!(vma->vm_flags & VM_EXEC))
6063 mmap_event->event_id.header.misc |= PERF_RECORD_MISC_MMAP_DATA;
6065 mmap_event->event_id.header.size = sizeof(mmap_event->event_id) + size;
6067 perf_event_aux(perf_event_mmap_output,
6074 void perf_event_mmap(struct vm_area_struct *vma)
6076 struct perf_mmap_event mmap_event;
6078 if (!atomic_read(&nr_mmap_events))
6081 mmap_event = (struct perf_mmap_event){
6087 .type = PERF_RECORD_MMAP,
6088 .misc = PERF_RECORD_MISC_USER,
6093 .start = vma->vm_start,
6094 .len = vma->vm_end - vma->vm_start,
6095 .pgoff = (u64)vma->vm_pgoff << PAGE_SHIFT,
6097 /* .maj (attr_mmap2 only) */
6098 /* .min (attr_mmap2 only) */
6099 /* .ino (attr_mmap2 only) */
6100 /* .ino_generation (attr_mmap2 only) */
6101 /* .prot (attr_mmap2 only) */
6102 /* .flags (attr_mmap2 only) */
6105 perf_event_mmap_event(&mmap_event);
6108 void perf_event_aux_event(struct perf_event *event, unsigned long head,
6109 unsigned long size, u64 flags)
6111 struct perf_output_handle handle;
6112 struct perf_sample_data sample;
6113 struct perf_aux_event {
6114 struct perf_event_header header;
6120 .type = PERF_RECORD_AUX,
6122 .size = sizeof(rec),
6130 perf_event_header__init_id(&rec.header, &sample, event);
6131 ret = perf_output_begin(&handle, event, rec.header.size);
6136 perf_output_put(&handle, rec);
6137 perf_event__output_id_sample(event, &handle, &sample);
6139 perf_output_end(&handle);
6143 * Lost/dropped samples logging
6145 void perf_log_lost_samples(struct perf_event *event, u64 lost)
6147 struct perf_output_handle handle;
6148 struct perf_sample_data sample;
6152 struct perf_event_header header;
6154 } lost_samples_event = {
6156 .type = PERF_RECORD_LOST_SAMPLES,
6158 .size = sizeof(lost_samples_event),
6163 perf_event_header__init_id(&lost_samples_event.header, &sample, event);
6165 ret = perf_output_begin(&handle, event,
6166 lost_samples_event.header.size);
6170 perf_output_put(&handle, lost_samples_event);
6171 perf_event__output_id_sample(event, &handle, &sample);
6172 perf_output_end(&handle);
6176 * context_switch tracking
6179 struct perf_switch_event {
6180 struct task_struct *task;
6181 struct task_struct *next_prev;
6184 struct perf_event_header header;
6190 static int perf_event_switch_match(struct perf_event *event)
6192 return event->attr.context_switch;
6195 static void perf_event_switch_output(struct perf_event *event, void *data)
6197 struct perf_switch_event *se = data;
6198 struct perf_output_handle handle;
6199 struct perf_sample_data sample;
6202 if (!perf_event_switch_match(event))
6205 /* Only CPU-wide events are allowed to see next/prev pid/tid */
6206 if (event->ctx->task) {
6207 se->event_id.header.type = PERF_RECORD_SWITCH;
6208 se->event_id.header.size = sizeof(se->event_id.header);
6210 se->event_id.header.type = PERF_RECORD_SWITCH_CPU_WIDE;
6211 se->event_id.header.size = sizeof(se->event_id);
6212 se->event_id.next_prev_pid =
6213 perf_event_pid(event, se->next_prev);
6214 se->event_id.next_prev_tid =
6215 perf_event_tid(event, se->next_prev);
6218 perf_event_header__init_id(&se->event_id.header, &sample, event);
6220 ret = perf_output_begin(&handle, event, se->event_id.header.size);
6224 if (event->ctx->task)
6225 perf_output_put(&handle, se->event_id.header);
6227 perf_output_put(&handle, se->event_id);
6229 perf_event__output_id_sample(event, &handle, &sample);
6231 perf_output_end(&handle);
6234 static void perf_event_switch(struct task_struct *task,
6235 struct task_struct *next_prev, bool sched_in)
6237 struct perf_switch_event switch_event;
6239 /* N.B. caller checks nr_switch_events != 0 */
6241 switch_event = (struct perf_switch_event){
6243 .next_prev = next_prev,
6247 .misc = sched_in ? 0 : PERF_RECORD_MISC_SWITCH_OUT,
6250 /* .next_prev_pid */
6251 /* .next_prev_tid */
6255 perf_event_aux(perf_event_switch_output,
6261 * IRQ throttle logging
6264 static void perf_log_throttle(struct perf_event *event, int enable)
6266 struct perf_output_handle handle;
6267 struct perf_sample_data sample;
6271 struct perf_event_header header;
6275 } throttle_event = {
6277 .type = PERF_RECORD_THROTTLE,
6279 .size = sizeof(throttle_event),
6281 .time = perf_event_clock(event),
6282 .id = primary_event_id(event),
6283 .stream_id = event->id,
6287 throttle_event.header.type = PERF_RECORD_UNTHROTTLE;
6289 perf_event_header__init_id(&throttle_event.header, &sample, event);
6291 ret = perf_output_begin(&handle, event,
6292 throttle_event.header.size);
6296 perf_output_put(&handle, throttle_event);
6297 perf_event__output_id_sample(event, &handle, &sample);
6298 perf_output_end(&handle);
6301 static void perf_log_itrace_start(struct perf_event *event)
6303 struct perf_output_handle handle;
6304 struct perf_sample_data sample;
6305 struct perf_aux_event {
6306 struct perf_event_header header;
6313 event = event->parent;
6315 if (!(event->pmu->capabilities & PERF_PMU_CAP_ITRACE) ||
6316 event->hw.itrace_started)
6319 rec.header.type = PERF_RECORD_ITRACE_START;
6320 rec.header.misc = 0;
6321 rec.header.size = sizeof(rec);
6322 rec.pid = perf_event_pid(event, current);
6323 rec.tid = perf_event_tid(event, current);
6325 perf_event_header__init_id(&rec.header, &sample, event);
6326 ret = perf_output_begin(&handle, event, rec.header.size);
6331 perf_output_put(&handle, rec);
6332 perf_event__output_id_sample(event, &handle, &sample);
6334 perf_output_end(&handle);
6338 * Generic event overflow handling, sampling.
6341 static int __perf_event_overflow(struct perf_event *event,
6342 int throttle, struct perf_sample_data *data,
6343 struct pt_regs *regs)
6345 int events = atomic_read(&event->event_limit);
6346 struct hw_perf_event *hwc = &event->hw;
6351 * Non-sampling counters might still use the PMI to fold short
6352 * hardware counters, ignore those.
6354 if (unlikely(!is_sampling_event(event)))
6357 seq = __this_cpu_read(perf_throttled_seq);
6358 if (seq != hwc->interrupts_seq) {
6359 hwc->interrupts_seq = seq;
6360 hwc->interrupts = 1;
6363 if (unlikely(throttle
6364 && hwc->interrupts >= max_samples_per_tick)) {
6365 __this_cpu_inc(perf_throttled_count);
6366 hwc->interrupts = MAX_INTERRUPTS;
6367 perf_log_throttle(event, 0);
6368 tick_nohz_full_kick();
6373 if (event->attr.freq) {
6374 u64 now = perf_clock();
6375 s64 delta = now - hwc->freq_time_stamp;
6377 hwc->freq_time_stamp = now;
6379 if (delta > 0 && delta < 2*TICK_NSEC)
6380 perf_adjust_period(event, delta, hwc->last_period, true);
6384 * XXX event_limit might not quite work as expected on inherited
6388 event->pending_kill = POLL_IN;
6389 if (events && atomic_dec_and_test(&event->event_limit)) {
6391 event->pending_kill = POLL_HUP;
6392 event->pending_disable = 1;
6393 irq_work_queue(&event->pending);
6396 if (event->overflow_handler)
6397 event->overflow_handler(event, data, regs);
6399 perf_event_output(event, data, regs);
6401 if (*perf_event_fasync(event) && event->pending_kill) {
6402 event->pending_wakeup = 1;
6403 irq_work_queue(&event->pending);
6409 int perf_event_overflow(struct perf_event *event,
6410 struct perf_sample_data *data,
6411 struct pt_regs *regs)
6413 return __perf_event_overflow(event, 1, data, regs);
6417 * Generic software event infrastructure
6420 struct swevent_htable {
6421 struct swevent_hlist *swevent_hlist;
6422 struct mutex hlist_mutex;
6425 /* Recursion avoidance in each contexts */
6426 int recursion[PERF_NR_CONTEXTS];
6429 static DEFINE_PER_CPU(struct swevent_htable, swevent_htable);
6432 * We directly increment event->count and keep a second value in
6433 * event->hw.period_left to count intervals. This period event
6434 * is kept in the range [-sample_period, 0] so that we can use the
6438 u64 perf_swevent_set_period(struct perf_event *event)
6440 struct hw_perf_event *hwc = &event->hw;
6441 u64 period = hwc->last_period;
6445 hwc->last_period = hwc->sample_period;
6448 old = val = local64_read(&hwc->period_left);
6452 nr = div64_u64(period + val, period);
6453 offset = nr * period;
6455 if (local64_cmpxchg(&hwc->period_left, old, val) != old)
6461 static void perf_swevent_overflow(struct perf_event *event, u64 overflow,
6462 struct perf_sample_data *data,
6463 struct pt_regs *regs)
6465 struct hw_perf_event *hwc = &event->hw;
6469 overflow = perf_swevent_set_period(event);
6471 if (hwc->interrupts == MAX_INTERRUPTS)
6474 for (; overflow; overflow--) {
6475 if (__perf_event_overflow(event, throttle,
6478 * We inhibit the overflow from happening when
6479 * hwc->interrupts == MAX_INTERRUPTS.
6487 static void perf_swevent_event(struct perf_event *event, u64 nr,
6488 struct perf_sample_data *data,
6489 struct pt_regs *regs)
6491 struct hw_perf_event *hwc = &event->hw;
6493 local64_add(nr, &event->count);
6498 if (!is_sampling_event(event))
6501 if ((event->attr.sample_type & PERF_SAMPLE_PERIOD) && !event->attr.freq) {
6503 return perf_swevent_overflow(event, 1, data, regs);
6505 data->period = event->hw.last_period;
6507 if (nr == 1 && hwc->sample_period == 1 && !event->attr.freq)
6508 return perf_swevent_overflow(event, 1, data, regs);
6510 if (local64_add_negative(nr, &hwc->period_left))
6513 perf_swevent_overflow(event, 0, data, regs);
6516 static int perf_exclude_event(struct perf_event *event,
6517 struct pt_regs *regs)
6519 if (event->hw.state & PERF_HES_STOPPED)
6523 if (event->attr.exclude_user && user_mode(regs))
6526 if (event->attr.exclude_kernel && !user_mode(regs))
6533 static int perf_swevent_match(struct perf_event *event,
6534 enum perf_type_id type,
6536 struct perf_sample_data *data,
6537 struct pt_regs *regs)
6539 if (event->attr.type != type)
6542 if (event->attr.config != event_id)
6545 if (perf_exclude_event(event, regs))
6551 static inline u64 swevent_hash(u64 type, u32 event_id)
6553 u64 val = event_id | (type << 32);
6555 return hash_64(val, SWEVENT_HLIST_BITS);
6558 static inline struct hlist_head *
6559 __find_swevent_head(struct swevent_hlist *hlist, u64 type, u32 event_id)
6561 u64 hash = swevent_hash(type, event_id);
6563 return &hlist->heads[hash];
6566 /* For the read side: events when they trigger */
6567 static inline struct hlist_head *
6568 find_swevent_head_rcu(struct swevent_htable *swhash, u64 type, u32 event_id)
6570 struct swevent_hlist *hlist;
6572 hlist = rcu_dereference(swhash->swevent_hlist);
6576 return __find_swevent_head(hlist, type, event_id);
6579 /* For the event head insertion and removal in the hlist */
6580 static inline struct hlist_head *
6581 find_swevent_head(struct swevent_htable *swhash, struct perf_event *event)
6583 struct swevent_hlist *hlist;
6584 u32 event_id = event->attr.config;
6585 u64 type = event->attr.type;
6588 * Event scheduling is always serialized against hlist allocation
6589 * and release. Which makes the protected version suitable here.
6590 * The context lock guarantees that.
6592 hlist = rcu_dereference_protected(swhash->swevent_hlist,
6593 lockdep_is_held(&event->ctx->lock));
6597 return __find_swevent_head(hlist, type, event_id);
6600 static void do_perf_sw_event(enum perf_type_id type, u32 event_id,
6602 struct perf_sample_data *data,
6603 struct pt_regs *regs)
6605 struct swevent_htable *swhash = this_cpu_ptr(&swevent_htable);
6606 struct perf_event *event;
6607 struct hlist_head *head;
6610 head = find_swevent_head_rcu(swhash, type, event_id);
6614 hlist_for_each_entry_rcu(event, head, hlist_entry) {
6615 if (perf_swevent_match(event, type, event_id, data, regs))
6616 perf_swevent_event(event, nr, data, regs);
6622 DEFINE_PER_CPU(struct pt_regs, __perf_regs[4]);
6624 int perf_swevent_get_recursion_context(void)
6626 struct swevent_htable *swhash = this_cpu_ptr(&swevent_htable);
6628 return get_recursion_context(swhash->recursion);
6630 EXPORT_SYMBOL_GPL(perf_swevent_get_recursion_context);
6632 inline void perf_swevent_put_recursion_context(int rctx)
6634 struct swevent_htable *swhash = this_cpu_ptr(&swevent_htable);
6636 put_recursion_context(swhash->recursion, rctx);
6639 void ___perf_sw_event(u32 event_id, u64 nr, struct pt_regs *regs, u64 addr)
6641 struct perf_sample_data data;
6643 if (WARN_ON_ONCE(!regs))
6646 perf_sample_data_init(&data, addr, 0);
6647 do_perf_sw_event(PERF_TYPE_SOFTWARE, event_id, nr, &data, regs);
6650 void __perf_sw_event(u32 event_id, u64 nr, struct pt_regs *regs, u64 addr)
6654 preempt_disable_notrace();
6655 rctx = perf_swevent_get_recursion_context();
6656 if (unlikely(rctx < 0))
6659 ___perf_sw_event(event_id, nr, regs, addr);
6661 perf_swevent_put_recursion_context(rctx);
6663 preempt_enable_notrace();
6666 static void perf_swevent_read(struct perf_event *event)
6670 static int perf_swevent_add(struct perf_event *event, int flags)
6672 struct swevent_htable *swhash = this_cpu_ptr(&swevent_htable);
6673 struct hw_perf_event *hwc = &event->hw;
6674 struct hlist_head *head;
6676 if (is_sampling_event(event)) {
6677 hwc->last_period = hwc->sample_period;
6678 perf_swevent_set_period(event);
6681 hwc->state = !(flags & PERF_EF_START);
6683 head = find_swevent_head(swhash, event);
6684 if (WARN_ON_ONCE(!head))
6687 hlist_add_head_rcu(&event->hlist_entry, head);
6688 perf_event_update_userpage(event);
6693 static void perf_swevent_del(struct perf_event *event, int flags)
6695 hlist_del_rcu(&event->hlist_entry);
6698 static void perf_swevent_start(struct perf_event *event, int flags)
6700 event->hw.state = 0;
6703 static void perf_swevent_stop(struct perf_event *event, int flags)
6705 event->hw.state = PERF_HES_STOPPED;
6708 /* Deref the hlist from the update side */
6709 static inline struct swevent_hlist *
6710 swevent_hlist_deref(struct swevent_htable *swhash)
6712 return rcu_dereference_protected(swhash->swevent_hlist,
6713 lockdep_is_held(&swhash->hlist_mutex));
6716 static void swevent_hlist_release(struct swevent_htable *swhash)
6718 struct swevent_hlist *hlist = swevent_hlist_deref(swhash);
6723 RCU_INIT_POINTER(swhash->swevent_hlist, NULL);
6724 kfree_rcu(hlist, rcu_head);
6727 static void swevent_hlist_put_cpu(struct perf_event *event, int cpu)
6729 struct swevent_htable *swhash = &per_cpu(swevent_htable, cpu);
6731 mutex_lock(&swhash->hlist_mutex);
6733 if (!--swhash->hlist_refcount)
6734 swevent_hlist_release(swhash);
6736 mutex_unlock(&swhash->hlist_mutex);
6739 static void swevent_hlist_put(struct perf_event *event)
6743 for_each_possible_cpu(cpu)
6744 swevent_hlist_put_cpu(event, cpu);
6747 static int swevent_hlist_get_cpu(struct perf_event *event, int cpu)
6749 struct swevent_htable *swhash = &per_cpu(swevent_htable, cpu);
6752 mutex_lock(&swhash->hlist_mutex);
6753 if (!swevent_hlist_deref(swhash) && cpu_online(cpu)) {
6754 struct swevent_hlist *hlist;
6756 hlist = kzalloc(sizeof(*hlist), GFP_KERNEL);
6761 rcu_assign_pointer(swhash->swevent_hlist, hlist);
6763 swhash->hlist_refcount++;
6765 mutex_unlock(&swhash->hlist_mutex);
6770 static int swevent_hlist_get(struct perf_event *event)
6773 int cpu, failed_cpu;
6776 for_each_possible_cpu(cpu) {
6777 err = swevent_hlist_get_cpu(event, cpu);
6787 for_each_possible_cpu(cpu) {
6788 if (cpu == failed_cpu)
6790 swevent_hlist_put_cpu(event, cpu);
6797 struct static_key perf_swevent_enabled[PERF_COUNT_SW_MAX];
6799 static void sw_perf_event_destroy(struct perf_event *event)
6801 u64 event_id = event->attr.config;
6803 WARN_ON(event->parent);
6805 static_key_slow_dec(&perf_swevent_enabled[event_id]);
6806 swevent_hlist_put(event);
6809 static int perf_swevent_init(struct perf_event *event)
6811 u64 event_id = event->attr.config;
6813 if (event->attr.type != PERF_TYPE_SOFTWARE)
6817 * no branch sampling for software events
6819 if (has_branch_stack(event))
6823 case PERF_COUNT_SW_CPU_CLOCK:
6824 case PERF_COUNT_SW_TASK_CLOCK:
6831 if (event_id >= PERF_COUNT_SW_MAX)
6834 if (!event->parent) {
6837 err = swevent_hlist_get(event);
6841 static_key_slow_inc(&perf_swevent_enabled[event_id]);
6842 event->destroy = sw_perf_event_destroy;
6848 static struct pmu perf_swevent = {
6849 .task_ctx_nr = perf_sw_context,
6851 .capabilities = PERF_PMU_CAP_NO_NMI,
6853 .event_init = perf_swevent_init,
6854 .add = perf_swevent_add,
6855 .del = perf_swevent_del,
6856 .start = perf_swevent_start,
6857 .stop = perf_swevent_stop,
6858 .read = perf_swevent_read,
6861 #ifdef CONFIG_EVENT_TRACING
6863 static int perf_tp_filter_match(struct perf_event *event,
6864 struct perf_sample_data *data)
6866 void *record = data->raw->data;
6868 /* only top level events have filters set */
6870 event = event->parent;
6872 if (likely(!event->filter) || filter_match_preds(event->filter, record))
6877 static int perf_tp_event_match(struct perf_event *event,
6878 struct perf_sample_data *data,
6879 struct pt_regs *regs)
6881 if (event->hw.state & PERF_HES_STOPPED)
6884 * All tracepoints are from kernel-space.
6886 if (event->attr.exclude_kernel)
6889 if (!perf_tp_filter_match(event, data))
6895 void perf_tp_event(u64 addr, u64 count, void *record, int entry_size,
6896 struct pt_regs *regs, struct hlist_head *head, int rctx,
6897 struct task_struct *task)
6899 struct perf_sample_data data;
6900 struct perf_event *event;
6902 struct perf_raw_record raw = {
6907 perf_sample_data_init(&data, addr, 0);
6910 hlist_for_each_entry_rcu(event, head, hlist_entry) {
6911 if (perf_tp_event_match(event, &data, regs))
6912 perf_swevent_event(event, count, &data, regs);
6916 * If we got specified a target task, also iterate its context and
6917 * deliver this event there too.
6919 if (task && task != current) {
6920 struct perf_event_context *ctx;
6921 struct trace_entry *entry = record;
6924 ctx = rcu_dereference(task->perf_event_ctxp[perf_sw_context]);
6928 list_for_each_entry_rcu(event, &ctx->event_list, event_entry) {
6929 if (event->attr.type != PERF_TYPE_TRACEPOINT)
6931 if (event->attr.config != entry->type)
6933 if (perf_tp_event_match(event, &data, regs))
6934 perf_swevent_event(event, count, &data, regs);
6940 perf_swevent_put_recursion_context(rctx);
6942 EXPORT_SYMBOL_GPL(perf_tp_event);
6944 static void tp_perf_event_destroy(struct perf_event *event)
6946 perf_trace_destroy(event);
6949 static int perf_tp_event_init(struct perf_event *event)
6953 if (event->attr.type != PERF_TYPE_TRACEPOINT)
6957 * no branch sampling for tracepoint events
6959 if (has_branch_stack(event))
6962 err = perf_trace_init(event);
6966 event->destroy = tp_perf_event_destroy;
6971 static struct pmu perf_tracepoint = {
6972 .task_ctx_nr = perf_sw_context,
6974 .event_init = perf_tp_event_init,
6975 .add = perf_trace_add,
6976 .del = perf_trace_del,
6977 .start = perf_swevent_start,
6978 .stop = perf_swevent_stop,
6979 .read = perf_swevent_read,
6982 static inline void perf_tp_register(void)
6984 perf_pmu_register(&perf_tracepoint, "tracepoint", PERF_TYPE_TRACEPOINT);
6987 static int perf_event_set_filter(struct perf_event *event, void __user *arg)
6992 if (event->attr.type != PERF_TYPE_TRACEPOINT)
6995 filter_str = strndup_user(arg, PAGE_SIZE);
6996 if (IS_ERR(filter_str))
6997 return PTR_ERR(filter_str);
6999 ret = ftrace_profile_set_filter(event, event->attr.config, filter_str);
7005 static void perf_event_free_filter(struct perf_event *event)
7007 ftrace_profile_free_filter(event);
7010 static int perf_event_set_bpf_prog(struct perf_event *event, u32 prog_fd)
7012 struct bpf_prog *prog;
7014 if (event->attr.type != PERF_TYPE_TRACEPOINT)
7017 if (event->tp_event->prog)
7020 if (!(event->tp_event->flags & TRACE_EVENT_FL_UKPROBE))
7021 /* bpf programs can only be attached to u/kprobes */
7024 prog = bpf_prog_get(prog_fd);
7026 return PTR_ERR(prog);
7028 if (prog->type != BPF_PROG_TYPE_KPROBE) {
7029 /* valid fd, but invalid bpf program type */
7034 event->tp_event->prog = prog;
7039 static void perf_event_free_bpf_prog(struct perf_event *event)
7041 struct bpf_prog *prog;
7043 if (!event->tp_event)
7046 prog = event->tp_event->prog;
7048 event->tp_event->prog = NULL;
7055 static inline void perf_tp_register(void)
7059 static int perf_event_set_filter(struct perf_event *event, void __user *arg)
7064 static void perf_event_free_filter(struct perf_event *event)
7068 static int perf_event_set_bpf_prog(struct perf_event *event, u32 prog_fd)
7073 static void perf_event_free_bpf_prog(struct perf_event *event)
7076 #endif /* CONFIG_EVENT_TRACING */
7078 #ifdef CONFIG_HAVE_HW_BREAKPOINT
7079 void perf_bp_event(struct perf_event *bp, void *data)
7081 struct perf_sample_data sample;
7082 struct pt_regs *regs = data;
7084 perf_sample_data_init(&sample, bp->attr.bp_addr, 0);
7086 if (!bp->hw.state && !perf_exclude_event(bp, regs))
7087 perf_swevent_event(bp, 1, &sample, regs);
7092 * hrtimer based swevent callback
7095 static enum hrtimer_restart perf_swevent_hrtimer(struct hrtimer *hrtimer)
7097 enum hrtimer_restart ret = HRTIMER_RESTART;
7098 struct perf_sample_data data;
7099 struct pt_regs *regs;
7100 struct perf_event *event;
7103 event = container_of(hrtimer, struct perf_event, hw.hrtimer);
7105 if (event->state != PERF_EVENT_STATE_ACTIVE)
7106 return HRTIMER_NORESTART;
7108 event->pmu->read(event);
7110 perf_sample_data_init(&data, 0, event->hw.last_period);
7111 regs = get_irq_regs();
7113 if (regs && !perf_exclude_event(event, regs)) {
7114 if (!(event->attr.exclude_idle && is_idle_task(current)))
7115 if (__perf_event_overflow(event, 1, &data, regs))
7116 ret = HRTIMER_NORESTART;
7119 period = max_t(u64, 10000, event->hw.sample_period);
7120 hrtimer_forward_now(hrtimer, ns_to_ktime(period));
7125 static void perf_swevent_start_hrtimer(struct perf_event *event)
7127 struct hw_perf_event *hwc = &event->hw;
7130 if (!is_sampling_event(event))
7133 period = local64_read(&hwc->period_left);
7138 local64_set(&hwc->period_left, 0);
7140 period = max_t(u64, 10000, hwc->sample_period);
7142 hrtimer_start(&hwc->hrtimer, ns_to_ktime(period),
7143 HRTIMER_MODE_REL_PINNED);
7146 static void perf_swevent_cancel_hrtimer(struct perf_event *event)
7148 struct hw_perf_event *hwc = &event->hw;
7150 if (is_sampling_event(event)) {
7151 ktime_t remaining = hrtimer_get_remaining(&hwc->hrtimer);
7152 local64_set(&hwc->period_left, ktime_to_ns(remaining));
7154 hrtimer_cancel(&hwc->hrtimer);
7158 static void perf_swevent_init_hrtimer(struct perf_event *event)
7160 struct hw_perf_event *hwc = &event->hw;
7162 if (!is_sampling_event(event))
7165 hrtimer_init(&hwc->hrtimer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
7166 hwc->hrtimer.function = perf_swevent_hrtimer;
7169 * Since hrtimers have a fixed rate, we can do a static freq->period
7170 * mapping and avoid the whole period adjust feedback stuff.
7172 if (event->attr.freq) {
7173 long freq = event->attr.sample_freq;
7175 event->attr.sample_period = NSEC_PER_SEC / freq;
7176 hwc->sample_period = event->attr.sample_period;
7177 local64_set(&hwc->period_left, hwc->sample_period);
7178 hwc->last_period = hwc->sample_period;
7179 event->attr.freq = 0;
7184 * Software event: cpu wall time clock
7187 static void cpu_clock_event_update(struct perf_event *event)
7192 now = local_clock();
7193 prev = local64_xchg(&event->hw.prev_count, now);
7194 local64_add(now - prev, &event->count);
7197 static void cpu_clock_event_start(struct perf_event *event, int flags)
7199 local64_set(&event->hw.prev_count, local_clock());
7200 perf_swevent_start_hrtimer(event);
7203 static void cpu_clock_event_stop(struct perf_event *event, int flags)
7205 perf_swevent_cancel_hrtimer(event);
7206 cpu_clock_event_update(event);
7209 static int cpu_clock_event_add(struct perf_event *event, int flags)
7211 if (flags & PERF_EF_START)
7212 cpu_clock_event_start(event, flags);
7213 perf_event_update_userpage(event);
7218 static void cpu_clock_event_del(struct perf_event *event, int flags)
7220 cpu_clock_event_stop(event, flags);
7223 static void cpu_clock_event_read(struct perf_event *event)
7225 cpu_clock_event_update(event);
7228 static int cpu_clock_event_init(struct perf_event *event)
7230 if (event->attr.type != PERF_TYPE_SOFTWARE)
7233 if (event->attr.config != PERF_COUNT_SW_CPU_CLOCK)
7237 * no branch sampling for software events
7239 if (has_branch_stack(event))
7242 perf_swevent_init_hrtimer(event);
7247 static struct pmu perf_cpu_clock = {
7248 .task_ctx_nr = perf_sw_context,
7250 .capabilities = PERF_PMU_CAP_NO_NMI,
7252 .event_init = cpu_clock_event_init,
7253 .add = cpu_clock_event_add,
7254 .del = cpu_clock_event_del,
7255 .start = cpu_clock_event_start,
7256 .stop = cpu_clock_event_stop,
7257 .read = cpu_clock_event_read,
7261 * Software event: task time clock
7264 static void task_clock_event_update(struct perf_event *event, u64 now)
7269 prev = local64_xchg(&event->hw.prev_count, now);
7271 local64_add(delta, &event->count);
7274 static void task_clock_event_start(struct perf_event *event, int flags)
7276 local64_set(&event->hw.prev_count, event->ctx->time);
7277 perf_swevent_start_hrtimer(event);
7280 static void task_clock_event_stop(struct perf_event *event, int flags)
7282 perf_swevent_cancel_hrtimer(event);
7283 task_clock_event_update(event, event->ctx->time);
7286 static int task_clock_event_add(struct perf_event *event, int flags)
7288 if (flags & PERF_EF_START)
7289 task_clock_event_start(event, flags);
7290 perf_event_update_userpage(event);
7295 static void task_clock_event_del(struct perf_event *event, int flags)
7297 task_clock_event_stop(event, PERF_EF_UPDATE);
7300 static void task_clock_event_read(struct perf_event *event)
7302 u64 now = perf_clock();
7303 u64 delta = now - event->ctx->timestamp;
7304 u64 time = event->ctx->time + delta;
7306 task_clock_event_update(event, time);
7309 static int task_clock_event_init(struct perf_event *event)
7311 if (event->attr.type != PERF_TYPE_SOFTWARE)
7314 if (event->attr.config != PERF_COUNT_SW_TASK_CLOCK)
7318 * no branch sampling for software events
7320 if (has_branch_stack(event))
7323 perf_swevent_init_hrtimer(event);
7328 static struct pmu perf_task_clock = {
7329 .task_ctx_nr = perf_sw_context,
7331 .capabilities = PERF_PMU_CAP_NO_NMI,
7333 .event_init = task_clock_event_init,
7334 .add = task_clock_event_add,
7335 .del = task_clock_event_del,
7336 .start = task_clock_event_start,
7337 .stop = task_clock_event_stop,
7338 .read = task_clock_event_read,
7341 static void perf_pmu_nop_void(struct pmu *pmu)
7345 static void perf_pmu_nop_txn(struct pmu *pmu, unsigned int flags)
7349 static int perf_pmu_nop_int(struct pmu *pmu)
7354 static DEFINE_PER_CPU(unsigned int, nop_txn_flags);
7356 static void perf_pmu_start_txn(struct pmu *pmu, unsigned int flags)
7358 __this_cpu_write(nop_txn_flags, flags);
7360 if (flags & ~PERF_PMU_TXN_ADD)
7363 perf_pmu_disable(pmu);
7366 static int perf_pmu_commit_txn(struct pmu *pmu)
7368 unsigned int flags = __this_cpu_read(nop_txn_flags);
7370 __this_cpu_write(nop_txn_flags, 0);
7372 if (flags & ~PERF_PMU_TXN_ADD)
7375 perf_pmu_enable(pmu);
7379 static void perf_pmu_cancel_txn(struct pmu *pmu)
7381 unsigned int flags = __this_cpu_read(nop_txn_flags);
7383 __this_cpu_write(nop_txn_flags, 0);
7385 if (flags & ~PERF_PMU_TXN_ADD)
7388 perf_pmu_enable(pmu);
7391 static int perf_event_idx_default(struct perf_event *event)
7397 * Ensures all contexts with the same task_ctx_nr have the same
7398 * pmu_cpu_context too.
7400 static struct perf_cpu_context __percpu *find_pmu_context(int ctxn)
7407 list_for_each_entry(pmu, &pmus, entry) {
7408 if (pmu->task_ctx_nr == ctxn)
7409 return pmu->pmu_cpu_context;
7415 static void update_pmu_context(struct pmu *pmu, struct pmu *old_pmu)
7419 for_each_possible_cpu(cpu) {
7420 struct perf_cpu_context *cpuctx;
7422 cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
7424 if (cpuctx->unique_pmu == old_pmu)
7425 cpuctx->unique_pmu = pmu;
7429 static void free_pmu_context(struct pmu *pmu)
7433 mutex_lock(&pmus_lock);
7435 * Like a real lame refcount.
7437 list_for_each_entry(i, &pmus, entry) {
7438 if (i->pmu_cpu_context == pmu->pmu_cpu_context) {
7439 update_pmu_context(i, pmu);
7444 free_percpu(pmu->pmu_cpu_context);
7446 mutex_unlock(&pmus_lock);
7448 static struct idr pmu_idr;
7451 type_show(struct device *dev, struct device_attribute *attr, char *page)
7453 struct pmu *pmu = dev_get_drvdata(dev);
7455 return snprintf(page, PAGE_SIZE-1, "%d\n", pmu->type);
7457 static DEVICE_ATTR_RO(type);
7460 perf_event_mux_interval_ms_show(struct device *dev,
7461 struct device_attribute *attr,
7464 struct pmu *pmu = dev_get_drvdata(dev);
7466 return snprintf(page, PAGE_SIZE-1, "%d\n", pmu->hrtimer_interval_ms);
7469 static DEFINE_MUTEX(mux_interval_mutex);
7472 perf_event_mux_interval_ms_store(struct device *dev,
7473 struct device_attribute *attr,
7474 const char *buf, size_t count)
7476 struct pmu *pmu = dev_get_drvdata(dev);
7477 int timer, cpu, ret;
7479 ret = kstrtoint(buf, 0, &timer);
7486 /* same value, noting to do */
7487 if (timer == pmu->hrtimer_interval_ms)
7490 mutex_lock(&mux_interval_mutex);
7491 pmu->hrtimer_interval_ms = timer;
7493 /* update all cpuctx for this PMU */
7495 for_each_online_cpu(cpu) {
7496 struct perf_cpu_context *cpuctx;
7497 cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
7498 cpuctx->hrtimer_interval = ns_to_ktime(NSEC_PER_MSEC * timer);
7500 cpu_function_call(cpu,
7501 (remote_function_f)perf_mux_hrtimer_restart, cpuctx);
7504 mutex_unlock(&mux_interval_mutex);
7508 static DEVICE_ATTR_RW(perf_event_mux_interval_ms);
7510 static struct attribute *pmu_dev_attrs[] = {
7511 &dev_attr_type.attr,
7512 &dev_attr_perf_event_mux_interval_ms.attr,
7515 ATTRIBUTE_GROUPS(pmu_dev);
7517 static int pmu_bus_running;
7518 static struct bus_type pmu_bus = {
7519 .name = "event_source",
7520 .dev_groups = pmu_dev_groups,
7523 static void pmu_dev_release(struct device *dev)
7528 static int pmu_dev_alloc(struct pmu *pmu)
7532 pmu->dev = kzalloc(sizeof(struct device), GFP_KERNEL);
7536 pmu->dev->groups = pmu->attr_groups;
7537 device_initialize(pmu->dev);
7538 ret = dev_set_name(pmu->dev, "%s", pmu->name);
7542 dev_set_drvdata(pmu->dev, pmu);
7543 pmu->dev->bus = &pmu_bus;
7544 pmu->dev->release = pmu_dev_release;
7545 ret = device_add(pmu->dev);
7553 put_device(pmu->dev);
7557 static struct lock_class_key cpuctx_mutex;
7558 static struct lock_class_key cpuctx_lock;
7560 int perf_pmu_register(struct pmu *pmu, const char *name, int type)
7564 mutex_lock(&pmus_lock);
7566 pmu->pmu_disable_count = alloc_percpu(int);
7567 if (!pmu->pmu_disable_count)
7576 type = idr_alloc(&pmu_idr, pmu, PERF_TYPE_MAX, 0, GFP_KERNEL);
7584 if (pmu_bus_running) {
7585 ret = pmu_dev_alloc(pmu);
7591 pmu->pmu_cpu_context = find_pmu_context(pmu->task_ctx_nr);
7592 if (pmu->pmu_cpu_context)
7593 goto got_cpu_context;
7596 pmu->pmu_cpu_context = alloc_percpu(struct perf_cpu_context);
7597 if (!pmu->pmu_cpu_context)
7600 for_each_possible_cpu(cpu) {
7601 struct perf_cpu_context *cpuctx;
7603 cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
7604 __perf_event_init_context(&cpuctx->ctx);
7605 lockdep_set_class(&cpuctx->ctx.mutex, &cpuctx_mutex);
7606 lockdep_set_class(&cpuctx->ctx.lock, &cpuctx_lock);
7607 cpuctx->ctx.pmu = pmu;
7609 __perf_mux_hrtimer_init(cpuctx, cpu);
7611 cpuctx->unique_pmu = pmu;
7615 if (!pmu->start_txn) {
7616 if (pmu->pmu_enable) {
7618 * If we have pmu_enable/pmu_disable calls, install
7619 * transaction stubs that use that to try and batch
7620 * hardware accesses.
7622 pmu->start_txn = perf_pmu_start_txn;
7623 pmu->commit_txn = perf_pmu_commit_txn;
7624 pmu->cancel_txn = perf_pmu_cancel_txn;
7626 pmu->start_txn = perf_pmu_nop_txn;
7627 pmu->commit_txn = perf_pmu_nop_int;
7628 pmu->cancel_txn = perf_pmu_nop_void;
7632 if (!pmu->pmu_enable) {
7633 pmu->pmu_enable = perf_pmu_nop_void;
7634 pmu->pmu_disable = perf_pmu_nop_void;
7637 if (!pmu->event_idx)
7638 pmu->event_idx = perf_event_idx_default;
7640 list_add_rcu(&pmu->entry, &pmus);
7641 atomic_set(&pmu->exclusive_cnt, 0);
7644 mutex_unlock(&pmus_lock);
7649 device_del(pmu->dev);
7650 put_device(pmu->dev);
7653 if (pmu->type >= PERF_TYPE_MAX)
7654 idr_remove(&pmu_idr, pmu->type);
7657 free_percpu(pmu->pmu_disable_count);
7660 EXPORT_SYMBOL_GPL(perf_pmu_register);
7662 void perf_pmu_unregister(struct pmu *pmu)
7664 mutex_lock(&pmus_lock);
7665 list_del_rcu(&pmu->entry);
7666 mutex_unlock(&pmus_lock);
7669 * We dereference the pmu list under both SRCU and regular RCU, so
7670 * synchronize against both of those.
7672 synchronize_srcu(&pmus_srcu);
7675 free_percpu(pmu->pmu_disable_count);
7676 if (pmu->type >= PERF_TYPE_MAX)
7677 idr_remove(&pmu_idr, pmu->type);
7678 device_del(pmu->dev);
7679 put_device(pmu->dev);
7680 free_pmu_context(pmu);
7682 EXPORT_SYMBOL_GPL(perf_pmu_unregister);
7684 static int perf_try_init_event(struct pmu *pmu, struct perf_event *event)
7686 struct perf_event_context *ctx = NULL;
7689 if (!try_module_get(pmu->module))
7692 if (event->group_leader != event) {
7694 * This ctx->mutex can nest when we're called through
7695 * inheritance. See the perf_event_ctx_lock_nested() comment.
7697 ctx = perf_event_ctx_lock_nested(event->group_leader,
7698 SINGLE_DEPTH_NESTING);
7703 ret = pmu->event_init(event);
7706 perf_event_ctx_unlock(event->group_leader, ctx);
7709 module_put(pmu->module);
7714 static struct pmu *perf_init_event(struct perf_event *event)
7716 struct pmu *pmu = NULL;
7720 idx = srcu_read_lock(&pmus_srcu);
7723 pmu = idr_find(&pmu_idr, event->attr.type);
7726 ret = perf_try_init_event(pmu, event);
7732 list_for_each_entry_rcu(pmu, &pmus, entry) {
7733 ret = perf_try_init_event(pmu, event);
7737 if (ret != -ENOENT) {
7742 pmu = ERR_PTR(-ENOENT);
7744 srcu_read_unlock(&pmus_srcu, idx);
7749 static void account_event_cpu(struct perf_event *event, int cpu)
7754 if (is_cgroup_event(event))
7755 atomic_inc(&per_cpu(perf_cgroup_events, cpu));
7758 static void account_event(struct perf_event *event)
7765 if (event->attach_state & PERF_ATTACH_TASK)
7767 if (event->attr.mmap || event->attr.mmap_data)
7768 atomic_inc(&nr_mmap_events);
7769 if (event->attr.comm)
7770 atomic_inc(&nr_comm_events);
7771 if (event->attr.task)
7772 atomic_inc(&nr_task_events);
7773 if (event->attr.freq) {
7774 if (atomic_inc_return(&nr_freq_events) == 1)
7775 tick_nohz_full_kick_all();
7777 if (event->attr.context_switch) {
7778 atomic_inc(&nr_switch_events);
7781 if (has_branch_stack(event))
7783 if (is_cgroup_event(event))
7787 static_key_slow_inc(&perf_sched_events.key);
7789 account_event_cpu(event, event->cpu);
7793 * Allocate and initialize a event structure
7795 static struct perf_event *
7796 perf_event_alloc(struct perf_event_attr *attr, int cpu,
7797 struct task_struct *task,
7798 struct perf_event *group_leader,
7799 struct perf_event *parent_event,
7800 perf_overflow_handler_t overflow_handler,
7801 void *context, int cgroup_fd)
7804 struct perf_event *event;
7805 struct hw_perf_event *hwc;
7808 if ((unsigned)cpu >= nr_cpu_ids) {
7809 if (!task || cpu != -1)
7810 return ERR_PTR(-EINVAL);
7813 event = kzalloc(sizeof(*event), GFP_KERNEL);
7815 return ERR_PTR(-ENOMEM);
7818 * Single events are their own group leaders, with an
7819 * empty sibling list:
7822 group_leader = event;
7824 mutex_init(&event->child_mutex);
7825 INIT_LIST_HEAD(&event->child_list);
7827 INIT_LIST_HEAD(&event->group_entry);
7828 INIT_LIST_HEAD(&event->event_entry);
7829 INIT_LIST_HEAD(&event->sibling_list);
7830 INIT_LIST_HEAD(&event->rb_entry);
7831 INIT_LIST_HEAD(&event->active_entry);
7832 INIT_HLIST_NODE(&event->hlist_entry);
7835 init_waitqueue_head(&event->waitq);
7836 init_irq_work(&event->pending, perf_pending_event);
7838 mutex_init(&event->mmap_mutex);
7840 atomic_long_set(&event->refcount, 1);
7842 event->attr = *attr;
7843 event->group_leader = group_leader;
7847 event->parent = parent_event;
7849 event->ns = get_pid_ns(task_active_pid_ns(current));
7850 event->id = atomic64_inc_return(&perf_event_id);
7852 event->state = PERF_EVENT_STATE_INACTIVE;
7855 event->attach_state = PERF_ATTACH_TASK;
7857 * XXX pmu::event_init needs to know what task to account to
7858 * and we cannot use the ctx information because we need the
7859 * pmu before we get a ctx.
7861 event->hw.target = task;
7864 event->clock = &local_clock;
7866 event->clock = parent_event->clock;
7868 if (!overflow_handler && parent_event) {
7869 overflow_handler = parent_event->overflow_handler;
7870 context = parent_event->overflow_handler_context;
7873 event->overflow_handler = overflow_handler;
7874 event->overflow_handler_context = context;
7876 perf_event__state_init(event);
7881 hwc->sample_period = attr->sample_period;
7882 if (attr->freq && attr->sample_freq)
7883 hwc->sample_period = 1;
7884 hwc->last_period = hwc->sample_period;
7886 local64_set(&hwc->period_left, hwc->sample_period);
7889 * we currently do not support PERF_FORMAT_GROUP on inherited events
7891 if (attr->inherit && (attr->read_format & PERF_FORMAT_GROUP))
7894 if (!has_branch_stack(event))
7895 event->attr.branch_sample_type = 0;
7897 if (cgroup_fd != -1) {
7898 err = perf_cgroup_connect(cgroup_fd, event, attr, group_leader);
7903 pmu = perf_init_event(event);
7906 else if (IS_ERR(pmu)) {
7911 err = exclusive_event_init(event);
7915 if (!event->parent) {
7916 if (event->attr.sample_type & PERF_SAMPLE_CALLCHAIN) {
7917 err = get_callchain_buffers();
7926 exclusive_event_destroy(event);
7930 event->destroy(event);
7931 module_put(pmu->module);
7933 if (is_cgroup_event(event))
7934 perf_detach_cgroup(event);
7936 put_pid_ns(event->ns);
7939 return ERR_PTR(err);
7942 static int perf_copy_attr(struct perf_event_attr __user *uattr,
7943 struct perf_event_attr *attr)
7948 if (!access_ok(VERIFY_WRITE, uattr, PERF_ATTR_SIZE_VER0))
7952 * zero the full structure, so that a short copy will be nice.
7954 memset(attr, 0, sizeof(*attr));
7956 ret = get_user(size, &uattr->size);
7960 if (size > PAGE_SIZE) /* silly large */
7963 if (!size) /* abi compat */
7964 size = PERF_ATTR_SIZE_VER0;
7966 if (size < PERF_ATTR_SIZE_VER0)
7970 * If we're handed a bigger struct than we know of,
7971 * ensure all the unknown bits are 0 - i.e. new
7972 * user-space does not rely on any kernel feature
7973 * extensions we dont know about yet.
7975 if (size > sizeof(*attr)) {
7976 unsigned char __user *addr;
7977 unsigned char __user *end;
7980 addr = (void __user *)uattr + sizeof(*attr);
7981 end = (void __user *)uattr + size;
7983 for (; addr < end; addr++) {
7984 ret = get_user(val, addr);
7990 size = sizeof(*attr);
7993 ret = copy_from_user(attr, uattr, size);
7997 if (attr->__reserved_1)
8000 if (attr->sample_type & ~(PERF_SAMPLE_MAX-1))
8003 if (attr->read_format & ~(PERF_FORMAT_MAX-1))
8006 if (attr->sample_type & PERF_SAMPLE_BRANCH_STACK) {
8007 u64 mask = attr->branch_sample_type;
8009 /* only using defined bits */
8010 if (mask & ~(PERF_SAMPLE_BRANCH_MAX-1))
8013 /* at least one branch bit must be set */
8014 if (!(mask & ~PERF_SAMPLE_BRANCH_PLM_ALL))
8017 /* propagate priv level, when not set for branch */
8018 if (!(mask & PERF_SAMPLE_BRANCH_PLM_ALL)) {
8020 /* exclude_kernel checked on syscall entry */
8021 if (!attr->exclude_kernel)
8022 mask |= PERF_SAMPLE_BRANCH_KERNEL;
8024 if (!attr->exclude_user)
8025 mask |= PERF_SAMPLE_BRANCH_USER;
8027 if (!attr->exclude_hv)
8028 mask |= PERF_SAMPLE_BRANCH_HV;
8030 * adjust user setting (for HW filter setup)
8032 attr->branch_sample_type = mask;
8034 /* privileged levels capture (kernel, hv): check permissions */
8035 if ((mask & PERF_SAMPLE_BRANCH_PERM_PLM)
8036 && perf_paranoid_kernel() && !capable(CAP_SYS_ADMIN))
8040 if (attr->sample_type & PERF_SAMPLE_REGS_USER) {
8041 ret = perf_reg_validate(attr->sample_regs_user);
8046 if (attr->sample_type & PERF_SAMPLE_STACK_USER) {
8047 if (!arch_perf_have_user_stack_dump())
8051 * We have __u32 type for the size, but so far
8052 * we can only use __u16 as maximum due to the
8053 * __u16 sample size limit.
8055 if (attr->sample_stack_user >= USHRT_MAX)
8057 else if (!IS_ALIGNED(attr->sample_stack_user, sizeof(u64)))
8061 if (attr->sample_type & PERF_SAMPLE_REGS_INTR)
8062 ret = perf_reg_validate(attr->sample_regs_intr);
8067 put_user(sizeof(*attr), &uattr->size);
8073 perf_event_set_output(struct perf_event *event, struct perf_event *output_event)
8075 struct ring_buffer *rb = NULL;
8081 /* don't allow circular references */
8082 if (event == output_event)
8086 * Don't allow cross-cpu buffers
8088 if (output_event->cpu != event->cpu)
8092 * If its not a per-cpu rb, it must be the same task.
8094 if (output_event->cpu == -1 && output_event->ctx != event->ctx)
8098 * Mixing clocks in the same buffer is trouble you don't need.
8100 if (output_event->clock != event->clock)
8104 * If both events generate aux data, they must be on the same PMU
8106 if (has_aux(event) && has_aux(output_event) &&
8107 event->pmu != output_event->pmu)
8111 mutex_lock(&event->mmap_mutex);
8112 /* Can't redirect output if we've got an active mmap() */
8113 if (atomic_read(&event->mmap_count))
8117 /* get the rb we want to redirect to */
8118 rb = ring_buffer_get(output_event);
8123 ring_buffer_attach(event, rb);
8127 mutex_unlock(&event->mmap_mutex);
8133 static void mutex_lock_double(struct mutex *a, struct mutex *b)
8139 mutex_lock_nested(b, SINGLE_DEPTH_NESTING);
8142 static int perf_event_set_clock(struct perf_event *event, clockid_t clk_id)
8144 bool nmi_safe = false;
8147 case CLOCK_MONOTONIC:
8148 event->clock = &ktime_get_mono_fast_ns;
8152 case CLOCK_MONOTONIC_RAW:
8153 event->clock = &ktime_get_raw_fast_ns;
8157 case CLOCK_REALTIME:
8158 event->clock = &ktime_get_real_ns;
8161 case CLOCK_BOOTTIME:
8162 event->clock = &ktime_get_boot_ns;
8166 event->clock = &ktime_get_tai_ns;
8173 if (!nmi_safe && !(event->pmu->capabilities & PERF_PMU_CAP_NO_NMI))
8180 * sys_perf_event_open - open a performance event, associate it to a task/cpu
8182 * @attr_uptr: event_id type attributes for monitoring/sampling
8185 * @group_fd: group leader event fd
8187 SYSCALL_DEFINE5(perf_event_open,
8188 struct perf_event_attr __user *, attr_uptr,
8189 pid_t, pid, int, cpu, int, group_fd, unsigned long, flags)
8191 struct perf_event *group_leader = NULL, *output_event = NULL;
8192 struct perf_event *event, *sibling;
8193 struct perf_event_attr attr;
8194 struct perf_event_context *ctx, *uninitialized_var(gctx);
8195 struct file *event_file = NULL;
8196 struct fd group = {NULL, 0};
8197 struct task_struct *task = NULL;
8202 int f_flags = O_RDWR;
8205 /* for future expandability... */
8206 if (flags & ~PERF_FLAG_ALL)
8209 err = perf_copy_attr(attr_uptr, &attr);
8213 if (!attr.exclude_kernel) {
8214 if (perf_paranoid_kernel() && !capable(CAP_SYS_ADMIN))
8219 if (attr.sample_freq > sysctl_perf_event_sample_rate)
8222 if (attr.sample_period & (1ULL << 63))
8227 * In cgroup mode, the pid argument is used to pass the fd
8228 * opened to the cgroup directory in cgroupfs. The cpu argument
8229 * designates the cpu on which to monitor threads from that
8232 if ((flags & PERF_FLAG_PID_CGROUP) && (pid == -1 || cpu == -1))
8235 if (flags & PERF_FLAG_FD_CLOEXEC)
8236 f_flags |= O_CLOEXEC;
8238 event_fd = get_unused_fd_flags(f_flags);
8242 if (group_fd != -1) {
8243 err = perf_fget_light(group_fd, &group);
8246 group_leader = group.file->private_data;
8247 if (flags & PERF_FLAG_FD_OUTPUT)
8248 output_event = group_leader;
8249 if (flags & PERF_FLAG_FD_NO_GROUP)
8250 group_leader = NULL;
8253 if (pid != -1 && !(flags & PERF_FLAG_PID_CGROUP)) {
8254 task = find_lively_task_by_vpid(pid);
8256 err = PTR_ERR(task);
8261 if (task && group_leader &&
8262 group_leader->attr.inherit != attr.inherit) {
8269 if (flags & PERF_FLAG_PID_CGROUP)
8272 event = perf_event_alloc(&attr, cpu, task, group_leader, NULL,
8273 NULL, NULL, cgroup_fd);
8274 if (IS_ERR(event)) {
8275 err = PTR_ERR(event);
8279 if (is_sampling_event(event)) {
8280 if (event->pmu->capabilities & PERF_PMU_CAP_NO_INTERRUPT) {
8286 account_event(event);
8289 * Special case software events and allow them to be part of
8290 * any hardware group.
8294 if (attr.use_clockid) {
8295 err = perf_event_set_clock(event, attr.clockid);
8301 (is_software_event(event) != is_software_event(group_leader))) {
8302 if (is_software_event(event)) {
8304 * If event and group_leader are not both a software
8305 * event, and event is, then group leader is not.
8307 * Allow the addition of software events to !software
8308 * groups, this is safe because software events never
8311 pmu = group_leader->pmu;
8312 } else if (is_software_event(group_leader) &&
8313 (group_leader->group_flags & PERF_GROUP_SOFTWARE)) {
8315 * In case the group is a pure software group, and we
8316 * try to add a hardware event, move the whole group to
8317 * the hardware context.
8324 * Get the target context (task or percpu):
8326 ctx = find_get_context(pmu, task, event);
8332 if ((pmu->capabilities & PERF_PMU_CAP_EXCLUSIVE) && group_leader) {
8338 put_task_struct(task);
8343 * Look up the group leader (we will attach this event to it):
8349 * Do not allow a recursive hierarchy (this new sibling
8350 * becoming part of another group-sibling):
8352 if (group_leader->group_leader != group_leader)
8355 /* All events in a group should have the same clock */
8356 if (group_leader->clock != event->clock)
8360 * Do not allow to attach to a group in a different
8361 * task or CPU context:
8365 * Make sure we're both on the same task, or both
8368 if (group_leader->ctx->task != ctx->task)
8372 * Make sure we're both events for the same CPU;
8373 * grouping events for different CPUs is broken; since
8374 * you can never concurrently schedule them anyhow.
8376 if (group_leader->cpu != event->cpu)
8379 if (group_leader->ctx != ctx)
8384 * Only a group leader can be exclusive or pinned
8386 if (attr.exclusive || attr.pinned)
8391 err = perf_event_set_output(event, output_event);
8396 event_file = anon_inode_getfile("[perf_event]", &perf_fops, event,
8398 if (IS_ERR(event_file)) {
8399 err = PTR_ERR(event_file);
8404 gctx = group_leader->ctx;
8405 mutex_lock_double(&gctx->mutex, &ctx->mutex);
8407 mutex_lock(&ctx->mutex);
8410 if (!perf_event_validate_size(event)) {
8416 * Must be under the same ctx::mutex as perf_install_in_context(),
8417 * because we need to serialize with concurrent event creation.
8419 if (!exclusive_event_installable(event, ctx)) {
8420 /* exclusive and group stuff are assumed mutually exclusive */
8421 WARN_ON_ONCE(move_group);
8427 WARN_ON_ONCE(ctx->parent_ctx);
8431 * See perf_event_ctx_lock() for comments on the details
8432 * of swizzling perf_event::ctx.
8434 perf_remove_from_context(group_leader, 0);
8436 list_for_each_entry(sibling, &group_leader->sibling_list,
8438 perf_remove_from_context(sibling, 0);
8443 * Wait for everybody to stop referencing the events through
8444 * the old lists, before installing it on new lists.
8449 * Install the group siblings before the group leader.
8451 * Because a group leader will try and install the entire group
8452 * (through the sibling list, which is still in-tact), we can
8453 * end up with siblings installed in the wrong context.
8455 * By installing siblings first we NO-OP because they're not
8456 * reachable through the group lists.
8458 list_for_each_entry(sibling, &group_leader->sibling_list,
8460 perf_event__state_init(sibling);
8461 perf_install_in_context(ctx, sibling, sibling->cpu);
8466 * Removing from the context ends up with disabled
8467 * event. What we want here is event in the initial
8468 * startup state, ready to be add into new context.
8470 perf_event__state_init(group_leader);
8471 perf_install_in_context(ctx, group_leader, group_leader->cpu);
8475 * Now that all events are installed in @ctx, nothing
8476 * references @gctx anymore, so drop the last reference we have
8483 * Precalculate sample_data sizes; do while holding ctx::mutex such
8484 * that we're serialized against further additions and before
8485 * perf_install_in_context() which is the point the event is active and
8486 * can use these values.
8488 perf_event__header_size(event);
8489 perf_event__id_header_size(event);
8491 event->owner = current;
8493 perf_install_in_context(ctx, event, event->cpu);
8494 perf_unpin_context(ctx);
8497 mutex_unlock(&gctx->mutex);
8498 mutex_unlock(&ctx->mutex);
8502 mutex_lock(¤t->perf_event_mutex);
8503 list_add_tail(&event->owner_entry, ¤t->perf_event_list);
8504 mutex_unlock(¤t->perf_event_mutex);
8507 * Drop the reference on the group_event after placing the
8508 * new event on the sibling_list. This ensures destruction
8509 * of the group leader will find the pointer to itself in
8510 * perf_group_detach().
8513 fd_install(event_fd, event_file);
8518 mutex_unlock(&gctx->mutex);
8519 mutex_unlock(&ctx->mutex);
8523 perf_unpin_context(ctx);
8531 put_task_struct(task);
8535 put_unused_fd(event_fd);
8540 * perf_event_create_kernel_counter
8542 * @attr: attributes of the counter to create
8543 * @cpu: cpu in which the counter is bound
8544 * @task: task to profile (NULL for percpu)
8547 perf_event_create_kernel_counter(struct perf_event_attr *attr, int cpu,
8548 struct task_struct *task,
8549 perf_overflow_handler_t overflow_handler,
8552 struct perf_event_context *ctx;
8553 struct perf_event *event;
8557 * Get the target context (task or percpu):
8560 event = perf_event_alloc(attr, cpu, task, NULL, NULL,
8561 overflow_handler, context, -1);
8562 if (IS_ERR(event)) {
8563 err = PTR_ERR(event);
8567 /* Mark owner so we could distinguish it from user events. */
8568 event->owner = TASK_TOMBSTONE;
8570 account_event(event);
8572 ctx = find_get_context(event->pmu, task, event);
8578 WARN_ON_ONCE(ctx->parent_ctx);
8579 mutex_lock(&ctx->mutex);
8580 if (!exclusive_event_installable(event, ctx)) {
8581 mutex_unlock(&ctx->mutex);
8582 perf_unpin_context(ctx);
8588 perf_install_in_context(ctx, event, cpu);
8589 perf_unpin_context(ctx);
8590 mutex_unlock(&ctx->mutex);
8597 return ERR_PTR(err);
8599 EXPORT_SYMBOL_GPL(perf_event_create_kernel_counter);
8601 void perf_pmu_migrate_context(struct pmu *pmu, int src_cpu, int dst_cpu)
8603 struct perf_event_context *src_ctx;
8604 struct perf_event_context *dst_ctx;
8605 struct perf_event *event, *tmp;
8608 src_ctx = &per_cpu_ptr(pmu->pmu_cpu_context, src_cpu)->ctx;
8609 dst_ctx = &per_cpu_ptr(pmu->pmu_cpu_context, dst_cpu)->ctx;
8612 * See perf_event_ctx_lock() for comments on the details
8613 * of swizzling perf_event::ctx.
8615 mutex_lock_double(&src_ctx->mutex, &dst_ctx->mutex);
8616 list_for_each_entry_safe(event, tmp, &src_ctx->event_list,
8618 perf_remove_from_context(event, 0);
8619 unaccount_event_cpu(event, src_cpu);
8621 list_add(&event->migrate_entry, &events);
8625 * Wait for the events to quiesce before re-instating them.
8630 * Re-instate events in 2 passes.
8632 * Skip over group leaders and only install siblings on this first
8633 * pass, siblings will not get enabled without a leader, however a
8634 * leader will enable its siblings, even if those are still on the old
8637 list_for_each_entry_safe(event, tmp, &events, migrate_entry) {
8638 if (event->group_leader == event)
8641 list_del(&event->migrate_entry);
8642 if (event->state >= PERF_EVENT_STATE_OFF)
8643 event->state = PERF_EVENT_STATE_INACTIVE;
8644 account_event_cpu(event, dst_cpu);
8645 perf_install_in_context(dst_ctx, event, dst_cpu);
8650 * Once all the siblings are setup properly, install the group leaders
8653 list_for_each_entry_safe(event, tmp, &events, migrate_entry) {
8654 list_del(&event->migrate_entry);
8655 if (event->state >= PERF_EVENT_STATE_OFF)
8656 event->state = PERF_EVENT_STATE_INACTIVE;
8657 account_event_cpu(event, dst_cpu);
8658 perf_install_in_context(dst_ctx, event, dst_cpu);
8661 mutex_unlock(&dst_ctx->mutex);
8662 mutex_unlock(&src_ctx->mutex);
8664 EXPORT_SYMBOL_GPL(perf_pmu_migrate_context);
8666 static void sync_child_event(struct perf_event *child_event,
8667 struct task_struct *child)
8669 struct perf_event *parent_event = child_event->parent;
8672 if (child_event->attr.inherit_stat)
8673 perf_event_read_event(child_event, child);
8675 child_val = perf_event_count(child_event);
8678 * Add back the child's count to the parent's count:
8680 atomic64_add(child_val, &parent_event->child_count);
8681 atomic64_add(child_event->total_time_enabled,
8682 &parent_event->child_total_time_enabled);
8683 atomic64_add(child_event->total_time_running,
8684 &parent_event->child_total_time_running);
8688 perf_event_exit_event(struct perf_event *child_event,
8689 struct perf_event_context *child_ctx,
8690 struct task_struct *child)
8692 struct perf_event *parent_event = child_event->parent;
8695 * Do not destroy the 'original' grouping; because of the context
8696 * switch optimization the original events could've ended up in a
8697 * random child task.
8699 * If we were to destroy the original group, all group related
8700 * operations would cease to function properly after this random
8703 * Do destroy all inherited groups, we don't care about those
8704 * and being thorough is better.
8706 raw_spin_lock_irq(&child_ctx->lock);
8707 WARN_ON_ONCE(child_ctx->is_active);
8710 perf_group_detach(child_event);
8711 list_del_event(child_event, child_ctx);
8712 child_event->state = PERF_EVENT_STATE_EXIT;
8713 raw_spin_unlock_irq(&child_ctx->lock);
8716 * Parent events are governed by their filedesc, retain them.
8718 if (!parent_event) {
8719 perf_event_wakeup(child_event);
8723 * Child events can be cleaned up.
8726 sync_child_event(child_event, child);
8729 * Remove this event from the parent's list
8731 WARN_ON_ONCE(parent_event->ctx->parent_ctx);
8732 mutex_lock(&parent_event->child_mutex);
8733 list_del_init(&child_event->child_list);
8734 mutex_unlock(&parent_event->child_mutex);
8737 * Kick perf_poll() for is_event_hup().
8739 perf_event_wakeup(parent_event);
8740 free_event(child_event);
8741 put_event(parent_event);
8744 static void perf_event_exit_task_context(struct task_struct *child, int ctxn)
8746 struct perf_event_context *child_ctx, *clone_ctx = NULL;
8747 struct perf_event *child_event, *next;
8749 WARN_ON_ONCE(child != current);
8751 child_ctx = perf_pin_task_context(child, ctxn);
8756 * In order to reduce the amount of tricky in ctx tear-down, we hold
8757 * ctx::mutex over the entire thing. This serializes against almost
8758 * everything that wants to access the ctx.
8760 * The exception is sys_perf_event_open() /
8761 * perf_event_create_kernel_count() which does find_get_context()
8762 * without ctx::mutex (it cannot because of the move_group double mutex
8763 * lock thing). See the comments in perf_install_in_context().
8765 * We can recurse on the same lock type through:
8767 * perf_event_exit_event()
8769 * mutex_lock(&ctx->mutex)
8771 * But since its the parent context it won't be the same instance.
8773 mutex_lock(&child_ctx->mutex);
8776 * In a single ctx::lock section, de-schedule the events and detach the
8777 * context from the task such that we cannot ever get it scheduled back
8780 raw_spin_lock_irq(&child_ctx->lock);
8781 task_ctx_sched_out(__get_cpu_context(child_ctx), child_ctx);
8784 * Now that the context is inactive, destroy the task <-> ctx relation
8785 * and mark the context dead.
8787 RCU_INIT_POINTER(child->perf_event_ctxp[ctxn], NULL);
8788 put_ctx(child_ctx); /* cannot be last */
8789 WRITE_ONCE(child_ctx->task, TASK_TOMBSTONE);
8790 put_task_struct(current); /* cannot be last */
8792 clone_ctx = unclone_ctx(child_ctx);
8793 raw_spin_unlock_irq(&child_ctx->lock);
8799 * Report the task dead after unscheduling the events so that we
8800 * won't get any samples after PERF_RECORD_EXIT. We can however still
8801 * get a few PERF_RECORD_READ events.
8803 perf_event_task(child, child_ctx, 0);
8805 list_for_each_entry_safe(child_event, next, &child_ctx->event_list, event_entry)
8806 perf_event_exit_event(child_event, child_ctx, child);
8808 mutex_unlock(&child_ctx->mutex);
8814 * When a child task exits, feed back event values to parent events.
8816 void perf_event_exit_task(struct task_struct *child)
8818 struct perf_event *event, *tmp;
8821 mutex_lock(&child->perf_event_mutex);
8822 list_for_each_entry_safe(event, tmp, &child->perf_event_list,
8824 list_del_init(&event->owner_entry);
8827 * Ensure the list deletion is visible before we clear
8828 * the owner, closes a race against perf_release() where
8829 * we need to serialize on the owner->perf_event_mutex.
8831 smp_store_release(&event->owner, NULL);
8833 mutex_unlock(&child->perf_event_mutex);
8835 for_each_task_context_nr(ctxn)
8836 perf_event_exit_task_context(child, ctxn);
8839 * The perf_event_exit_task_context calls perf_event_task
8840 * with child's task_ctx, which generates EXIT events for
8841 * child contexts and sets child->perf_event_ctxp[] to NULL.
8842 * At this point we need to send EXIT events to cpu contexts.
8844 perf_event_task(child, NULL, 0);
8847 static void perf_free_event(struct perf_event *event,
8848 struct perf_event_context *ctx)
8850 struct perf_event *parent = event->parent;
8852 if (WARN_ON_ONCE(!parent))
8855 mutex_lock(&parent->child_mutex);
8856 list_del_init(&event->child_list);
8857 mutex_unlock(&parent->child_mutex);
8861 raw_spin_lock_irq(&ctx->lock);
8862 perf_group_detach(event);
8863 list_del_event(event, ctx);
8864 raw_spin_unlock_irq(&ctx->lock);
8869 * Free an unexposed, unused context as created by inheritance by
8870 * perf_event_init_task below, used by fork() in case of fail.
8872 * Not all locks are strictly required, but take them anyway to be nice and
8873 * help out with the lockdep assertions.
8875 void perf_event_free_task(struct task_struct *task)
8877 struct perf_event_context *ctx;
8878 struct perf_event *event, *tmp;
8881 for_each_task_context_nr(ctxn) {
8882 ctx = task->perf_event_ctxp[ctxn];
8886 mutex_lock(&ctx->mutex);
8888 list_for_each_entry_safe(event, tmp, &ctx->pinned_groups,
8890 perf_free_event(event, ctx);
8892 list_for_each_entry_safe(event, tmp, &ctx->flexible_groups,
8894 perf_free_event(event, ctx);
8896 if (!list_empty(&ctx->pinned_groups) ||
8897 !list_empty(&ctx->flexible_groups))
8900 mutex_unlock(&ctx->mutex);
8906 void perf_event_delayed_put(struct task_struct *task)
8910 for_each_task_context_nr(ctxn)
8911 WARN_ON_ONCE(task->perf_event_ctxp[ctxn]);
8914 struct file *perf_event_get(unsigned int fd)
8918 file = fget_raw(fd);
8920 return ERR_PTR(-EBADF);
8922 if (file->f_op != &perf_fops) {
8924 return ERR_PTR(-EBADF);
8930 const struct perf_event_attr *perf_event_attrs(struct perf_event *event)
8933 return ERR_PTR(-EINVAL);
8935 return &event->attr;
8939 * inherit a event from parent task to child task:
8941 static struct perf_event *
8942 inherit_event(struct perf_event *parent_event,
8943 struct task_struct *parent,
8944 struct perf_event_context *parent_ctx,
8945 struct task_struct *child,
8946 struct perf_event *group_leader,
8947 struct perf_event_context *child_ctx)
8949 enum perf_event_active_state parent_state = parent_event->state;
8950 struct perf_event *child_event;
8951 unsigned long flags;
8954 * Instead of creating recursive hierarchies of events,
8955 * we link inherited events back to the original parent,
8956 * which has a filp for sure, which we use as the reference
8959 if (parent_event->parent)
8960 parent_event = parent_event->parent;
8962 child_event = perf_event_alloc(&parent_event->attr,
8965 group_leader, parent_event,
8967 if (IS_ERR(child_event))
8970 if (is_orphaned_event(parent_event) ||
8971 !atomic_long_inc_not_zero(&parent_event->refcount)) {
8972 free_event(child_event);
8979 * Make the child state follow the state of the parent event,
8980 * not its attr.disabled bit. We hold the parent's mutex,
8981 * so we won't race with perf_event_{en, dis}able_family.
8983 if (parent_state >= PERF_EVENT_STATE_INACTIVE)
8984 child_event->state = PERF_EVENT_STATE_INACTIVE;
8986 child_event->state = PERF_EVENT_STATE_OFF;
8988 if (parent_event->attr.freq) {
8989 u64 sample_period = parent_event->hw.sample_period;
8990 struct hw_perf_event *hwc = &child_event->hw;
8992 hwc->sample_period = sample_period;
8993 hwc->last_period = sample_period;
8995 local64_set(&hwc->period_left, sample_period);
8998 child_event->ctx = child_ctx;
8999 child_event->overflow_handler = parent_event->overflow_handler;
9000 child_event->overflow_handler_context
9001 = parent_event->overflow_handler_context;
9004 * Precalculate sample_data sizes
9006 perf_event__header_size(child_event);
9007 perf_event__id_header_size(child_event);
9010 * Link it up in the child's context:
9012 raw_spin_lock_irqsave(&child_ctx->lock, flags);
9013 add_event_to_ctx(child_event, child_ctx);
9014 raw_spin_unlock_irqrestore(&child_ctx->lock, flags);
9017 * Link this into the parent event's child list
9019 WARN_ON_ONCE(parent_event->ctx->parent_ctx);
9020 mutex_lock(&parent_event->child_mutex);
9021 list_add_tail(&child_event->child_list, &parent_event->child_list);
9022 mutex_unlock(&parent_event->child_mutex);
9027 static int inherit_group(struct perf_event *parent_event,
9028 struct task_struct *parent,
9029 struct perf_event_context *parent_ctx,
9030 struct task_struct *child,
9031 struct perf_event_context *child_ctx)
9033 struct perf_event *leader;
9034 struct perf_event *sub;
9035 struct perf_event *child_ctr;
9037 leader = inherit_event(parent_event, parent, parent_ctx,
9038 child, NULL, child_ctx);
9040 return PTR_ERR(leader);
9041 list_for_each_entry(sub, &parent_event->sibling_list, group_entry) {
9042 child_ctr = inherit_event(sub, parent, parent_ctx,
9043 child, leader, child_ctx);
9044 if (IS_ERR(child_ctr))
9045 return PTR_ERR(child_ctr);
9051 inherit_task_group(struct perf_event *event, struct task_struct *parent,
9052 struct perf_event_context *parent_ctx,
9053 struct task_struct *child, int ctxn,
9057 struct perf_event_context *child_ctx;
9059 if (!event->attr.inherit) {
9064 child_ctx = child->perf_event_ctxp[ctxn];
9067 * This is executed from the parent task context, so
9068 * inherit events that have been marked for cloning.
9069 * First allocate and initialize a context for the
9073 child_ctx = alloc_perf_context(parent_ctx->pmu, child);
9077 child->perf_event_ctxp[ctxn] = child_ctx;
9080 ret = inherit_group(event, parent, parent_ctx,
9090 * Initialize the perf_event context in task_struct
9092 static int perf_event_init_context(struct task_struct *child, int ctxn)
9094 struct perf_event_context *child_ctx, *parent_ctx;
9095 struct perf_event_context *cloned_ctx;
9096 struct perf_event *event;
9097 struct task_struct *parent = current;
9098 int inherited_all = 1;
9099 unsigned long flags;
9102 if (likely(!parent->perf_event_ctxp[ctxn]))
9106 * If the parent's context is a clone, pin it so it won't get
9109 parent_ctx = perf_pin_task_context(parent, ctxn);
9114 * No need to check if parent_ctx != NULL here; since we saw
9115 * it non-NULL earlier, the only reason for it to become NULL
9116 * is if we exit, and since we're currently in the middle of
9117 * a fork we can't be exiting at the same time.
9121 * Lock the parent list. No need to lock the child - not PID
9122 * hashed yet and not running, so nobody can access it.
9124 mutex_lock(&parent_ctx->mutex);
9127 * We dont have to disable NMIs - we are only looking at
9128 * the list, not manipulating it:
9130 list_for_each_entry(event, &parent_ctx->pinned_groups, group_entry) {
9131 ret = inherit_task_group(event, parent, parent_ctx,
9132 child, ctxn, &inherited_all);
9138 * We can't hold ctx->lock when iterating the ->flexible_group list due
9139 * to allocations, but we need to prevent rotation because
9140 * rotate_ctx() will change the list from interrupt context.
9142 raw_spin_lock_irqsave(&parent_ctx->lock, flags);
9143 parent_ctx->rotate_disable = 1;
9144 raw_spin_unlock_irqrestore(&parent_ctx->lock, flags);
9146 list_for_each_entry(event, &parent_ctx->flexible_groups, group_entry) {
9147 ret = inherit_task_group(event, parent, parent_ctx,
9148 child, ctxn, &inherited_all);
9153 raw_spin_lock_irqsave(&parent_ctx->lock, flags);
9154 parent_ctx->rotate_disable = 0;
9156 child_ctx = child->perf_event_ctxp[ctxn];
9158 if (child_ctx && inherited_all) {
9160 * Mark the child context as a clone of the parent
9161 * context, or of whatever the parent is a clone of.
9163 * Note that if the parent is a clone, the holding of
9164 * parent_ctx->lock avoids it from being uncloned.
9166 cloned_ctx = parent_ctx->parent_ctx;
9168 child_ctx->parent_ctx = cloned_ctx;
9169 child_ctx->parent_gen = parent_ctx->parent_gen;
9171 child_ctx->parent_ctx = parent_ctx;
9172 child_ctx->parent_gen = parent_ctx->generation;
9174 get_ctx(child_ctx->parent_ctx);
9177 raw_spin_unlock_irqrestore(&parent_ctx->lock, flags);
9178 mutex_unlock(&parent_ctx->mutex);
9180 perf_unpin_context(parent_ctx);
9181 put_ctx(parent_ctx);
9187 * Initialize the perf_event context in task_struct
9189 int perf_event_init_task(struct task_struct *child)
9193 memset(child->perf_event_ctxp, 0, sizeof(child->perf_event_ctxp));
9194 mutex_init(&child->perf_event_mutex);
9195 INIT_LIST_HEAD(&child->perf_event_list);
9197 for_each_task_context_nr(ctxn) {
9198 ret = perf_event_init_context(child, ctxn);
9200 perf_event_free_task(child);
9208 static void __init perf_event_init_all_cpus(void)
9210 struct swevent_htable *swhash;
9213 for_each_possible_cpu(cpu) {
9214 swhash = &per_cpu(swevent_htable, cpu);
9215 mutex_init(&swhash->hlist_mutex);
9216 INIT_LIST_HEAD(&per_cpu(active_ctx_list, cpu));
9220 static void perf_event_init_cpu(int cpu)
9222 struct swevent_htable *swhash = &per_cpu(swevent_htable, cpu);
9224 mutex_lock(&swhash->hlist_mutex);
9225 if (swhash->hlist_refcount > 0) {
9226 struct swevent_hlist *hlist;
9228 hlist = kzalloc_node(sizeof(*hlist), GFP_KERNEL, cpu_to_node(cpu));
9230 rcu_assign_pointer(swhash->swevent_hlist, hlist);
9232 mutex_unlock(&swhash->hlist_mutex);
9235 #if defined CONFIG_HOTPLUG_CPU || defined CONFIG_KEXEC_CORE
9236 static void __perf_event_exit_context(void *__info)
9238 struct perf_event_context *ctx = __info;
9239 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
9240 struct perf_event *event;
9242 raw_spin_lock(&ctx->lock);
9243 list_for_each_entry(event, &ctx->event_list, event_entry)
9244 __perf_remove_from_context(event, cpuctx, ctx, (void *)DETACH_GROUP);
9245 raw_spin_unlock(&ctx->lock);
9248 static void perf_event_exit_cpu_context(int cpu)
9250 struct perf_event_context *ctx;
9254 idx = srcu_read_lock(&pmus_srcu);
9255 list_for_each_entry_rcu(pmu, &pmus, entry) {
9256 ctx = &per_cpu_ptr(pmu->pmu_cpu_context, cpu)->ctx;
9258 mutex_lock(&ctx->mutex);
9259 smp_call_function_single(cpu, __perf_event_exit_context, ctx, 1);
9260 mutex_unlock(&ctx->mutex);
9262 srcu_read_unlock(&pmus_srcu, idx);
9265 static void perf_event_exit_cpu(int cpu)
9267 perf_event_exit_cpu_context(cpu);
9270 static inline void perf_event_exit_cpu(int cpu) { }
9274 perf_reboot(struct notifier_block *notifier, unsigned long val, void *v)
9278 for_each_online_cpu(cpu)
9279 perf_event_exit_cpu(cpu);
9285 * Run the perf reboot notifier at the very last possible moment so that
9286 * the generic watchdog code runs as long as possible.
9288 static struct notifier_block perf_reboot_notifier = {
9289 .notifier_call = perf_reboot,
9290 .priority = INT_MIN,
9294 perf_cpu_notify(struct notifier_block *self, unsigned long action, void *hcpu)
9296 unsigned int cpu = (long)hcpu;
9298 switch (action & ~CPU_TASKS_FROZEN) {
9300 case CPU_UP_PREPARE:
9301 case CPU_DOWN_FAILED:
9302 perf_event_init_cpu(cpu);
9305 case CPU_UP_CANCELED:
9306 case CPU_DOWN_PREPARE:
9307 perf_event_exit_cpu(cpu);
9316 void __init perf_event_init(void)
9322 perf_event_init_all_cpus();
9323 init_srcu_struct(&pmus_srcu);
9324 perf_pmu_register(&perf_swevent, "software", PERF_TYPE_SOFTWARE);
9325 perf_pmu_register(&perf_cpu_clock, NULL, -1);
9326 perf_pmu_register(&perf_task_clock, NULL, -1);
9328 perf_cpu_notifier(perf_cpu_notify);
9329 register_reboot_notifier(&perf_reboot_notifier);
9331 ret = init_hw_breakpoint();
9332 WARN(ret, "hw_breakpoint initialization failed with: %d", ret);
9334 /* do not patch jump label more than once per second */
9335 jump_label_rate_limit(&perf_sched_events, HZ);
9338 * Build time assertion that we keep the data_head at the intended
9339 * location. IOW, validation we got the __reserved[] size right.
9341 BUILD_BUG_ON((offsetof(struct perf_event_mmap_page, data_head))
9345 ssize_t perf_event_sysfs_show(struct device *dev, struct device_attribute *attr,
9348 struct perf_pmu_events_attr *pmu_attr =
9349 container_of(attr, struct perf_pmu_events_attr, attr);
9351 if (pmu_attr->event_str)
9352 return sprintf(page, "%s\n", pmu_attr->event_str);
9357 static int __init perf_event_sysfs_init(void)
9362 mutex_lock(&pmus_lock);
9364 ret = bus_register(&pmu_bus);
9368 list_for_each_entry(pmu, &pmus, entry) {
9369 if (!pmu->name || pmu->type < 0)
9372 ret = pmu_dev_alloc(pmu);
9373 WARN(ret, "Failed to register pmu: %s, reason %d\n", pmu->name, ret);
9375 pmu_bus_running = 1;
9379 mutex_unlock(&pmus_lock);
9383 device_initcall(perf_event_sysfs_init);
9385 #ifdef CONFIG_CGROUP_PERF
9386 static struct cgroup_subsys_state *
9387 perf_cgroup_css_alloc(struct cgroup_subsys_state *parent_css)
9389 struct perf_cgroup *jc;
9391 jc = kzalloc(sizeof(*jc), GFP_KERNEL);
9393 return ERR_PTR(-ENOMEM);
9395 jc->info = alloc_percpu(struct perf_cgroup_info);
9398 return ERR_PTR(-ENOMEM);
9404 static void perf_cgroup_css_free(struct cgroup_subsys_state *css)
9406 struct perf_cgroup *jc = container_of(css, struct perf_cgroup, css);
9408 free_percpu(jc->info);
9412 static int __perf_cgroup_move(void *info)
9414 struct task_struct *task = info;
9416 perf_cgroup_switch(task, PERF_CGROUP_SWOUT | PERF_CGROUP_SWIN);
9421 static void perf_cgroup_attach(struct cgroup_taskset *tset)
9423 struct task_struct *task;
9424 struct cgroup_subsys_state *css;
9426 cgroup_taskset_for_each(task, css, tset)
9427 task_function_call(task, __perf_cgroup_move, task);
9430 struct cgroup_subsys perf_event_cgrp_subsys = {
9431 .css_alloc = perf_cgroup_css_alloc,
9432 .css_free = perf_cgroup_css_free,
9433 .attach = perf_cgroup_attach,
9435 #endif /* CONFIG_CGROUP_PERF */