2 * Performance events core code:
4 * Copyright (C) 2008 Thomas Gleixner <tglx@linutronix.de>
5 * Copyright (C) 2008-2011 Red Hat, Inc., Ingo Molnar
6 * Copyright (C) 2008-2011 Red Hat, Inc., Peter Zijlstra
7 * Copyright © 2009 Paul Mackerras, IBM Corp. <paulus@au1.ibm.com>
9 * For licensing details see kernel-base/COPYING
14 #include <linux/cpu.h>
15 #include <linux/smp.h>
16 #include <linux/idr.h>
17 #include <linux/file.h>
18 #include <linux/poll.h>
19 #include <linux/slab.h>
20 #include <linux/hash.h>
21 #include <linux/tick.h>
22 #include <linux/sysfs.h>
23 #include <linux/dcache.h>
24 #include <linux/percpu.h>
25 #include <linux/ptrace.h>
26 #include <linux/reboot.h>
27 #include <linux/vmstat.h>
28 #include <linux/device.h>
29 #include <linux/export.h>
30 #include <linux/vmalloc.h>
31 #include <linux/hardirq.h>
32 #include <linux/rculist.h>
33 #include <linux/uaccess.h>
34 #include <linux/syscalls.h>
35 #include <linux/anon_inodes.h>
36 #include <linux/kernel_stat.h>
37 #include <linux/cgroup.h>
38 #include <linux/perf_event.h>
39 #include <linux/trace_events.h>
40 #include <linux/hw_breakpoint.h>
41 #include <linux/mm_types.h>
42 #include <linux/module.h>
43 #include <linux/mman.h>
44 #include <linux/compat.h>
45 #include <linux/bpf.h>
46 #include <linux/filter.h>
50 #include <asm/irq_regs.h>
52 typedef int (*remote_function_f)(void *);
54 struct remote_function_call {
55 struct task_struct *p;
56 remote_function_f func;
61 static void remote_function(void *data)
63 struct remote_function_call *tfc = data;
64 struct task_struct *p = tfc->p;
68 if (task_cpu(p) != smp_processor_id())
72 * Now that we're on right CPU with IRQs disabled, we can test
73 * if we hit the right task without races.
76 tfc->ret = -ESRCH; /* No such (running) process */
81 tfc->ret = tfc->func(tfc->info);
85 * task_function_call - call a function on the cpu on which a task runs
86 * @p: the task to evaluate
87 * @func: the function to be called
88 * @info: the function call argument
90 * Calls the function @func when the task is currently running. This might
91 * be on the current CPU, which just calls the function directly
93 * returns: @func return value, or
94 * -ESRCH - when the process isn't running
95 * -EAGAIN - when the process moved away
98 task_function_call(struct task_struct *p, remote_function_f func, void *info)
100 struct remote_function_call data = {
109 ret = smp_call_function_single(task_cpu(p), remote_function, &data, 1);
112 } while (ret == -EAGAIN);
118 * cpu_function_call - call a function on the cpu
119 * @func: the function to be called
120 * @info: the function call argument
122 * Calls the function @func on the remote cpu.
124 * returns: @func return value or -ENXIO when the cpu is offline
126 static int cpu_function_call(int cpu, remote_function_f func, void *info)
128 struct remote_function_call data = {
132 .ret = -ENXIO, /* No such CPU */
135 smp_call_function_single(cpu, remote_function, &data, 1);
140 static inline struct perf_cpu_context *
141 __get_cpu_context(struct perf_event_context *ctx)
143 return this_cpu_ptr(ctx->pmu->pmu_cpu_context);
146 static void perf_ctx_lock(struct perf_cpu_context *cpuctx,
147 struct perf_event_context *ctx)
149 raw_spin_lock(&cpuctx->ctx.lock);
151 raw_spin_lock(&ctx->lock);
154 static void perf_ctx_unlock(struct perf_cpu_context *cpuctx,
155 struct perf_event_context *ctx)
158 raw_spin_unlock(&ctx->lock);
159 raw_spin_unlock(&cpuctx->ctx.lock);
162 #define TASK_TOMBSTONE ((void *)-1L)
164 static bool is_kernel_event(struct perf_event *event)
166 return READ_ONCE(event->owner) == TASK_TOMBSTONE;
170 * On task ctx scheduling...
172 * When !ctx->nr_events a task context will not be scheduled. This means
173 * we can disable the scheduler hooks (for performance) without leaving
174 * pending task ctx state.
176 * This however results in two special cases:
178 * - removing the last event from a task ctx; this is relatively straight
179 * forward and is done in __perf_remove_from_context.
181 * - adding the first event to a task ctx; this is tricky because we cannot
182 * rely on ctx->is_active and therefore cannot use event_function_call().
183 * See perf_install_in_context().
185 * If ctx->nr_events, then ctx->is_active and cpuctx->task_ctx are set.
188 typedef void (*event_f)(struct perf_event *, struct perf_cpu_context *,
189 struct perf_event_context *, void *);
191 struct event_function_struct {
192 struct perf_event *event;
197 static int event_function(void *info)
199 struct event_function_struct *efs = info;
200 struct perf_event *event = efs->event;
201 struct perf_event_context *ctx = event->ctx;
202 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
203 struct perf_event_context *task_ctx = cpuctx->task_ctx;
206 WARN_ON_ONCE(!irqs_disabled());
208 perf_ctx_lock(cpuctx, task_ctx);
210 * Since we do the IPI call without holding ctx->lock things can have
211 * changed, double check we hit the task we set out to hit.
214 if (ctx->task != current) {
220 * We only use event_function_call() on established contexts,
221 * and event_function() is only ever called when active (or
222 * rather, we'll have bailed in task_function_call() or the
223 * above ctx->task != current test), therefore we must have
224 * ctx->is_active here.
226 WARN_ON_ONCE(!ctx->is_active);
228 * And since we have ctx->is_active, cpuctx->task_ctx must
231 WARN_ON_ONCE(task_ctx != ctx);
233 WARN_ON_ONCE(&cpuctx->ctx != ctx);
236 efs->func(event, cpuctx, ctx, efs->data);
238 perf_ctx_unlock(cpuctx, task_ctx);
243 static void event_function_local(struct perf_event *event, event_f func, void *data)
245 struct event_function_struct efs = {
251 int ret = event_function(&efs);
255 static void event_function_call(struct perf_event *event, event_f func, void *data)
257 struct perf_event_context *ctx = event->ctx;
258 struct task_struct *task = READ_ONCE(ctx->task); /* verified in event_function */
259 struct event_function_struct efs = {
265 if (!event->parent) {
267 * If this is a !child event, we must hold ctx::mutex to
268 * stabilize the the event->ctx relation. See
269 * perf_event_ctx_lock().
271 lockdep_assert_held(&ctx->mutex);
275 cpu_function_call(event->cpu, event_function, &efs);
279 if (task == TASK_TOMBSTONE)
283 if (!task_function_call(task, event_function, &efs))
286 raw_spin_lock_irq(&ctx->lock);
288 * Reload the task pointer, it might have been changed by
289 * a concurrent perf_event_context_sched_out().
292 if (task == TASK_TOMBSTONE) {
293 raw_spin_unlock_irq(&ctx->lock);
296 if (ctx->is_active) {
297 raw_spin_unlock_irq(&ctx->lock);
300 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,
320 EVENT_ALL = EVENT_FLEXIBLE | EVENT_PINNED,
324 * perf_sched_events : >0 events exist
325 * perf_cgroup_events: >0 per-cpu cgroup events exist on this cpu
328 static void perf_sched_delayed(struct work_struct *work);
329 DEFINE_STATIC_KEY_FALSE(perf_sched_events);
330 static DECLARE_DELAYED_WORK(perf_sched_work, perf_sched_delayed);
331 static DEFINE_MUTEX(perf_sched_mutex);
332 static atomic_t perf_sched_count;
334 static DEFINE_PER_CPU(atomic_t, perf_cgroup_events);
335 static DEFINE_PER_CPU(int, perf_sched_cb_usages);
337 static atomic_t nr_mmap_events __read_mostly;
338 static atomic_t nr_comm_events __read_mostly;
339 static atomic_t nr_task_events __read_mostly;
340 static atomic_t nr_freq_events __read_mostly;
341 static atomic_t nr_switch_events __read_mostly;
343 static LIST_HEAD(pmus);
344 static DEFINE_MUTEX(pmus_lock);
345 static struct srcu_struct pmus_srcu;
348 * perf event paranoia level:
349 * -1 - not paranoid at all
350 * 0 - disallow raw tracepoint access for unpriv
351 * 1 - disallow cpu events for unpriv
352 * 2 - disallow kernel profiling for unpriv
354 int sysctl_perf_event_paranoid __read_mostly = 1;
356 /* Minimum for 512 kiB + 1 user control page */
357 int sysctl_perf_event_mlock __read_mostly = 512 + (PAGE_SIZE / 1024); /* 'free' kiB per user */
360 * max perf event sample rate
362 #define DEFAULT_MAX_SAMPLE_RATE 100000
363 #define DEFAULT_SAMPLE_PERIOD_NS (NSEC_PER_SEC / DEFAULT_MAX_SAMPLE_RATE)
364 #define DEFAULT_CPU_TIME_MAX_PERCENT 25
366 int sysctl_perf_event_sample_rate __read_mostly = DEFAULT_MAX_SAMPLE_RATE;
368 static int max_samples_per_tick __read_mostly = DIV_ROUND_UP(DEFAULT_MAX_SAMPLE_RATE, HZ);
369 static int perf_sample_period_ns __read_mostly = DEFAULT_SAMPLE_PERIOD_NS;
371 static int perf_sample_allowed_ns __read_mostly =
372 DEFAULT_SAMPLE_PERIOD_NS * DEFAULT_CPU_TIME_MAX_PERCENT / 100;
374 static void update_perf_cpu_limits(void)
376 u64 tmp = perf_sample_period_ns;
378 tmp *= sysctl_perf_cpu_time_max_percent;
380 ACCESS_ONCE(perf_sample_allowed_ns) = tmp;
383 static int perf_rotate_context(struct perf_cpu_context *cpuctx);
385 int perf_proc_update_handler(struct ctl_table *table, int write,
386 void __user *buffer, size_t *lenp,
389 int ret = proc_dointvec_minmax(table, write, buffer, lenp, ppos);
394 max_samples_per_tick = DIV_ROUND_UP(sysctl_perf_event_sample_rate, HZ);
395 perf_sample_period_ns = NSEC_PER_SEC / sysctl_perf_event_sample_rate;
396 update_perf_cpu_limits();
401 int sysctl_perf_cpu_time_max_percent __read_mostly = DEFAULT_CPU_TIME_MAX_PERCENT;
403 int perf_cpu_time_max_percent_handler(struct ctl_table *table, int write,
404 void __user *buffer, size_t *lenp,
407 int ret = proc_dointvec(table, write, buffer, lenp, ppos);
412 update_perf_cpu_limits();
418 * perf samples are done in some very critical code paths (NMIs).
419 * If they take too much CPU time, the system can lock up and not
420 * get any real work done. This will drop the sample rate when
421 * we detect that events are taking too long.
423 #define NR_ACCUMULATED_SAMPLES 128
424 static DEFINE_PER_CPU(u64, running_sample_length);
426 static void perf_duration_warn(struct irq_work *w)
428 u64 allowed_ns = ACCESS_ONCE(perf_sample_allowed_ns);
429 u64 avg_local_sample_len;
430 u64 local_samples_len;
432 local_samples_len = __this_cpu_read(running_sample_length);
433 avg_local_sample_len = local_samples_len/NR_ACCUMULATED_SAMPLES;
435 printk_ratelimited(KERN_WARNING
436 "perf interrupt took too long (%lld > %lld), lowering "
437 "kernel.perf_event_max_sample_rate to %d\n",
438 avg_local_sample_len, allowed_ns >> 1,
439 sysctl_perf_event_sample_rate);
442 static DEFINE_IRQ_WORK(perf_duration_work, perf_duration_warn);
444 void perf_sample_event_took(u64 sample_len_ns)
446 u64 allowed_ns = ACCESS_ONCE(perf_sample_allowed_ns);
447 u64 avg_local_sample_len;
448 u64 local_samples_len;
453 /* decay the counter by 1 average sample */
454 local_samples_len = __this_cpu_read(running_sample_length);
455 local_samples_len -= local_samples_len/NR_ACCUMULATED_SAMPLES;
456 local_samples_len += sample_len_ns;
457 __this_cpu_write(running_sample_length, local_samples_len);
460 * note: this will be biased artifically low until we have
461 * seen NR_ACCUMULATED_SAMPLES. Doing it this way keeps us
462 * from having to maintain a count.
464 avg_local_sample_len = local_samples_len/NR_ACCUMULATED_SAMPLES;
466 if (avg_local_sample_len <= allowed_ns)
469 if (max_samples_per_tick <= 1)
472 max_samples_per_tick = DIV_ROUND_UP(max_samples_per_tick, 2);
473 sysctl_perf_event_sample_rate = max_samples_per_tick * HZ;
474 perf_sample_period_ns = NSEC_PER_SEC / sysctl_perf_event_sample_rate;
476 update_perf_cpu_limits();
478 if (!irq_work_queue(&perf_duration_work)) {
479 early_printk("perf interrupt took too long (%lld > %lld), lowering "
480 "kernel.perf_event_max_sample_rate to %d\n",
481 avg_local_sample_len, allowed_ns >> 1,
482 sysctl_perf_event_sample_rate);
486 static atomic64_t perf_event_id;
488 static void cpu_ctx_sched_out(struct perf_cpu_context *cpuctx,
489 enum event_type_t event_type);
491 static void cpu_ctx_sched_in(struct perf_cpu_context *cpuctx,
492 enum event_type_t event_type,
493 struct task_struct *task);
495 static void update_context_time(struct perf_event_context *ctx);
496 static u64 perf_event_time(struct perf_event *event);
498 void __weak perf_event_print_debug(void) { }
500 extern __weak const char *perf_pmu_name(void)
505 static inline u64 perf_clock(void)
507 return local_clock();
510 static inline u64 perf_event_clock(struct perf_event *event)
512 return event->clock();
515 #ifdef CONFIG_CGROUP_PERF
518 perf_cgroup_match(struct perf_event *event)
520 struct perf_event_context *ctx = event->ctx;
521 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
523 /* @event doesn't care about cgroup */
527 /* wants specific cgroup scope but @cpuctx isn't associated with any */
532 * Cgroup scoping is recursive. An event enabled for a cgroup is
533 * also enabled for all its descendant cgroups. If @cpuctx's
534 * cgroup is a descendant of @event's (the test covers identity
535 * case), it's a match.
537 return cgroup_is_descendant(cpuctx->cgrp->css.cgroup,
538 event->cgrp->css.cgroup);
541 static inline void perf_detach_cgroup(struct perf_event *event)
543 css_put(&event->cgrp->css);
547 static inline int is_cgroup_event(struct perf_event *event)
549 return event->cgrp != NULL;
552 static inline u64 perf_cgroup_event_time(struct perf_event *event)
554 struct perf_cgroup_info *t;
556 t = per_cpu_ptr(event->cgrp->info, event->cpu);
560 static inline void __update_cgrp_time(struct perf_cgroup *cgrp)
562 struct perf_cgroup_info *info;
567 info = this_cpu_ptr(cgrp->info);
569 info->time += now - info->timestamp;
570 info->timestamp = now;
573 static inline void update_cgrp_time_from_cpuctx(struct perf_cpu_context *cpuctx)
575 struct perf_cgroup *cgrp_out = cpuctx->cgrp;
577 __update_cgrp_time(cgrp_out);
580 static inline void update_cgrp_time_from_event(struct perf_event *event)
582 struct perf_cgroup *cgrp;
585 * ensure we access cgroup data only when needed and
586 * when we know the cgroup is pinned (css_get)
588 if (!is_cgroup_event(event))
591 cgrp = perf_cgroup_from_task(current, event->ctx);
593 * Do not update time when cgroup is not active
595 if (cgrp == event->cgrp)
596 __update_cgrp_time(event->cgrp);
600 perf_cgroup_set_timestamp(struct task_struct *task,
601 struct perf_event_context *ctx)
603 struct perf_cgroup *cgrp;
604 struct perf_cgroup_info *info;
607 * ctx->lock held by caller
608 * ensure we do not access cgroup data
609 * unless we have the cgroup pinned (css_get)
611 if (!task || !ctx->nr_cgroups)
614 cgrp = perf_cgroup_from_task(task, ctx);
615 info = this_cpu_ptr(cgrp->info);
616 info->timestamp = ctx->timestamp;
619 #define PERF_CGROUP_SWOUT 0x1 /* cgroup switch out every event */
620 #define PERF_CGROUP_SWIN 0x2 /* cgroup switch in events based on task */
623 * reschedule events based on the cgroup constraint of task.
625 * mode SWOUT : schedule out everything
626 * mode SWIN : schedule in based on cgroup for next
628 static void perf_cgroup_switch(struct task_struct *task, int mode)
630 struct perf_cpu_context *cpuctx;
635 * disable interrupts to avoid geting nr_cgroup
636 * changes via __perf_event_disable(). Also
639 local_irq_save(flags);
642 * we reschedule only in the presence of cgroup
643 * constrained events.
646 list_for_each_entry_rcu(pmu, &pmus, entry) {
647 cpuctx = this_cpu_ptr(pmu->pmu_cpu_context);
648 if (cpuctx->unique_pmu != pmu)
649 continue; /* ensure we process each cpuctx once */
652 * perf_cgroup_events says at least one
653 * context on this CPU has cgroup events.
655 * ctx->nr_cgroups reports the number of cgroup
656 * events for a context.
658 if (cpuctx->ctx.nr_cgroups > 0) {
659 perf_ctx_lock(cpuctx, cpuctx->task_ctx);
660 perf_pmu_disable(cpuctx->ctx.pmu);
662 if (mode & PERF_CGROUP_SWOUT) {
663 cpu_ctx_sched_out(cpuctx, EVENT_ALL);
665 * must not be done before ctxswout due
666 * to event_filter_match() in event_sched_out()
671 if (mode & PERF_CGROUP_SWIN) {
672 WARN_ON_ONCE(cpuctx->cgrp);
674 * set cgrp before ctxsw in to allow
675 * event_filter_match() to not have to pass
677 * we pass the cpuctx->ctx to perf_cgroup_from_task()
678 * because cgorup events are only per-cpu
680 cpuctx->cgrp = perf_cgroup_from_task(task, &cpuctx->ctx);
681 cpu_ctx_sched_in(cpuctx, EVENT_ALL, task);
683 perf_pmu_enable(cpuctx->ctx.pmu);
684 perf_ctx_unlock(cpuctx, cpuctx->task_ctx);
688 local_irq_restore(flags);
691 static inline void perf_cgroup_sched_out(struct task_struct *task,
692 struct task_struct *next)
694 struct perf_cgroup *cgrp1;
695 struct perf_cgroup *cgrp2 = NULL;
699 * we come here when we know perf_cgroup_events > 0
700 * we do not need to pass the ctx here because we know
701 * we are holding the rcu lock
703 cgrp1 = perf_cgroup_from_task(task, NULL);
704 cgrp2 = perf_cgroup_from_task(next, NULL);
707 * only schedule out current cgroup events if we know
708 * that we are switching to a different cgroup. Otherwise,
709 * do no touch the cgroup events.
712 perf_cgroup_switch(task, PERF_CGROUP_SWOUT);
717 static inline void perf_cgroup_sched_in(struct task_struct *prev,
718 struct task_struct *task)
720 struct perf_cgroup *cgrp1;
721 struct perf_cgroup *cgrp2 = NULL;
725 * we come here when we know perf_cgroup_events > 0
726 * we do not need to pass the ctx here because we know
727 * we are holding the rcu lock
729 cgrp1 = perf_cgroup_from_task(task, NULL);
730 cgrp2 = perf_cgroup_from_task(prev, NULL);
733 * only need to schedule in cgroup events if we are changing
734 * cgroup during ctxsw. Cgroup events were not scheduled
735 * out of ctxsw out if that was not the case.
738 perf_cgroup_switch(task, PERF_CGROUP_SWIN);
743 static inline int perf_cgroup_connect(int fd, struct perf_event *event,
744 struct perf_event_attr *attr,
745 struct perf_event *group_leader)
747 struct perf_cgroup *cgrp;
748 struct cgroup_subsys_state *css;
749 struct fd f = fdget(fd);
755 css = css_tryget_online_from_dir(f.file->f_path.dentry,
756 &perf_event_cgrp_subsys);
762 cgrp = container_of(css, struct perf_cgroup, css);
766 * all events in a group must monitor
767 * the same cgroup because a task belongs
768 * to only one perf cgroup at a time
770 if (group_leader && group_leader->cgrp != cgrp) {
771 perf_detach_cgroup(event);
780 perf_cgroup_set_shadow_time(struct perf_event *event, u64 now)
782 struct perf_cgroup_info *t;
783 t = per_cpu_ptr(event->cgrp->info, event->cpu);
784 event->shadow_ctx_time = now - t->timestamp;
788 perf_cgroup_defer_enabled(struct perf_event *event)
791 * when the current task's perf cgroup does not match
792 * the event's, we need to remember to call the
793 * perf_mark_enable() function the first time a task with
794 * a matching perf cgroup is scheduled in.
796 if (is_cgroup_event(event) && !perf_cgroup_match(event))
797 event->cgrp_defer_enabled = 1;
801 perf_cgroup_mark_enabled(struct perf_event *event,
802 struct perf_event_context *ctx)
804 struct perf_event *sub;
805 u64 tstamp = perf_event_time(event);
807 if (!event->cgrp_defer_enabled)
810 event->cgrp_defer_enabled = 0;
812 event->tstamp_enabled = tstamp - event->total_time_enabled;
813 list_for_each_entry(sub, &event->sibling_list, group_entry) {
814 if (sub->state >= PERF_EVENT_STATE_INACTIVE) {
815 sub->tstamp_enabled = tstamp - sub->total_time_enabled;
816 sub->cgrp_defer_enabled = 0;
820 #else /* !CONFIG_CGROUP_PERF */
823 perf_cgroup_match(struct perf_event *event)
828 static inline void perf_detach_cgroup(struct perf_event *event)
831 static inline int is_cgroup_event(struct perf_event *event)
836 static inline u64 perf_cgroup_event_cgrp_time(struct perf_event *event)
841 static inline void update_cgrp_time_from_event(struct perf_event *event)
845 static inline void update_cgrp_time_from_cpuctx(struct perf_cpu_context *cpuctx)
849 static inline void perf_cgroup_sched_out(struct task_struct *task,
850 struct task_struct *next)
854 static inline void perf_cgroup_sched_in(struct task_struct *prev,
855 struct task_struct *task)
859 static inline int perf_cgroup_connect(pid_t pid, struct perf_event *event,
860 struct perf_event_attr *attr,
861 struct perf_event *group_leader)
867 perf_cgroup_set_timestamp(struct task_struct *task,
868 struct perf_event_context *ctx)
873 perf_cgroup_switch(struct task_struct *task, struct task_struct *next)
878 perf_cgroup_set_shadow_time(struct perf_event *event, u64 now)
882 static inline u64 perf_cgroup_event_time(struct perf_event *event)
888 perf_cgroup_defer_enabled(struct perf_event *event)
893 perf_cgroup_mark_enabled(struct perf_event *event,
894 struct perf_event_context *ctx)
900 * set default to be dependent on timer tick just
903 #define PERF_CPU_HRTIMER (1000 / HZ)
905 * function must be called with interrupts disbled
907 static enum hrtimer_restart perf_mux_hrtimer_handler(struct hrtimer *hr)
909 struct perf_cpu_context *cpuctx;
912 WARN_ON(!irqs_disabled());
914 cpuctx = container_of(hr, struct perf_cpu_context, hrtimer);
915 rotations = perf_rotate_context(cpuctx);
917 raw_spin_lock(&cpuctx->hrtimer_lock);
919 hrtimer_forward_now(hr, cpuctx->hrtimer_interval);
921 cpuctx->hrtimer_active = 0;
922 raw_spin_unlock(&cpuctx->hrtimer_lock);
924 return rotations ? HRTIMER_RESTART : HRTIMER_NORESTART;
927 static void __perf_mux_hrtimer_init(struct perf_cpu_context *cpuctx, int cpu)
929 struct hrtimer *timer = &cpuctx->hrtimer;
930 struct pmu *pmu = cpuctx->ctx.pmu;
933 /* no multiplexing needed for SW PMU */
934 if (pmu->task_ctx_nr == perf_sw_context)
938 * check default is sane, if not set then force to
939 * default interval (1/tick)
941 interval = pmu->hrtimer_interval_ms;
943 interval = pmu->hrtimer_interval_ms = PERF_CPU_HRTIMER;
945 cpuctx->hrtimer_interval = ns_to_ktime(NSEC_PER_MSEC * interval);
947 raw_spin_lock_init(&cpuctx->hrtimer_lock);
948 hrtimer_init(timer, CLOCK_MONOTONIC, HRTIMER_MODE_ABS_PINNED);
949 timer->function = perf_mux_hrtimer_handler;
952 static int perf_mux_hrtimer_restart(struct perf_cpu_context *cpuctx)
954 struct hrtimer *timer = &cpuctx->hrtimer;
955 struct pmu *pmu = cpuctx->ctx.pmu;
959 if (pmu->task_ctx_nr == perf_sw_context)
962 raw_spin_lock_irqsave(&cpuctx->hrtimer_lock, flags);
963 if (!cpuctx->hrtimer_active) {
964 cpuctx->hrtimer_active = 1;
965 hrtimer_forward_now(timer, cpuctx->hrtimer_interval);
966 hrtimer_start_expires(timer, HRTIMER_MODE_ABS_PINNED);
968 raw_spin_unlock_irqrestore(&cpuctx->hrtimer_lock, flags);
973 void perf_pmu_disable(struct pmu *pmu)
975 int *count = this_cpu_ptr(pmu->pmu_disable_count);
977 pmu->pmu_disable(pmu);
980 void perf_pmu_enable(struct pmu *pmu)
982 int *count = this_cpu_ptr(pmu->pmu_disable_count);
984 pmu->pmu_enable(pmu);
987 static DEFINE_PER_CPU(struct list_head, active_ctx_list);
990 * perf_event_ctx_activate(), perf_event_ctx_deactivate(), and
991 * perf_event_task_tick() are fully serialized because they're strictly cpu
992 * affine and perf_event_ctx{activate,deactivate} are called with IRQs
993 * disabled, while perf_event_task_tick is called from IRQ context.
995 static void perf_event_ctx_activate(struct perf_event_context *ctx)
997 struct list_head *head = this_cpu_ptr(&active_ctx_list);
999 WARN_ON(!irqs_disabled());
1001 WARN_ON(!list_empty(&ctx->active_ctx_list));
1003 list_add(&ctx->active_ctx_list, head);
1006 static void perf_event_ctx_deactivate(struct perf_event_context *ctx)
1008 WARN_ON(!irqs_disabled());
1010 WARN_ON(list_empty(&ctx->active_ctx_list));
1012 list_del_init(&ctx->active_ctx_list);
1015 static void get_ctx(struct perf_event_context *ctx)
1017 WARN_ON(!atomic_inc_not_zero(&ctx->refcount));
1020 static void free_ctx(struct rcu_head *head)
1022 struct perf_event_context *ctx;
1024 ctx = container_of(head, struct perf_event_context, rcu_head);
1025 kfree(ctx->task_ctx_data);
1029 static void put_ctx(struct perf_event_context *ctx)
1031 if (atomic_dec_and_test(&ctx->refcount)) {
1032 if (ctx->parent_ctx)
1033 put_ctx(ctx->parent_ctx);
1034 if (ctx->task && ctx->task != TASK_TOMBSTONE)
1035 put_task_struct(ctx->task);
1036 call_rcu(&ctx->rcu_head, free_ctx);
1041 * Because of perf_event::ctx migration in sys_perf_event_open::move_group and
1042 * perf_pmu_migrate_context() we need some magic.
1044 * Those places that change perf_event::ctx will hold both
1045 * perf_event_ctx::mutex of the 'old' and 'new' ctx value.
1047 * Lock ordering is by mutex address. There are two other sites where
1048 * perf_event_context::mutex nests and those are:
1050 * - perf_event_exit_task_context() [ child , 0 ]
1051 * perf_event_exit_event()
1052 * put_event() [ parent, 1 ]
1054 * - perf_event_init_context() [ parent, 0 ]
1055 * inherit_task_group()
1058 * perf_event_alloc()
1060 * perf_try_init_event() [ child , 1 ]
1062 * While it appears there is an obvious deadlock here -- the parent and child
1063 * nesting levels are inverted between the two. This is in fact safe because
1064 * life-time rules separate them. That is an exiting task cannot fork, and a
1065 * spawning task cannot (yet) exit.
1067 * But remember that that these are parent<->child context relations, and
1068 * migration does not affect children, therefore these two orderings should not
1071 * The change in perf_event::ctx does not affect children (as claimed above)
1072 * because the sys_perf_event_open() case will install a new event and break
1073 * the ctx parent<->child relation, and perf_pmu_migrate_context() is only
1074 * concerned with cpuctx and that doesn't have children.
1076 * The places that change perf_event::ctx will issue:
1078 * perf_remove_from_context();
1079 * synchronize_rcu();
1080 * perf_install_in_context();
1082 * to affect the change. The remove_from_context() + synchronize_rcu() should
1083 * quiesce the event, after which we can install it in the new location. This
1084 * means that only external vectors (perf_fops, prctl) can perturb the event
1085 * while in transit. Therefore all such accessors should also acquire
1086 * perf_event_context::mutex to serialize against this.
1088 * However; because event->ctx can change while we're waiting to acquire
1089 * ctx->mutex we must be careful and use the below perf_event_ctx_lock()
1093 * task_struct::perf_event_mutex
1094 * perf_event_context::mutex
1095 * perf_event::child_mutex;
1096 * perf_event_context::lock
1097 * perf_event::mmap_mutex
1100 static struct perf_event_context *
1101 perf_event_ctx_lock_nested(struct perf_event *event, int nesting)
1103 struct perf_event_context *ctx;
1107 ctx = ACCESS_ONCE(event->ctx);
1108 if (!atomic_inc_not_zero(&ctx->refcount)) {
1114 mutex_lock_nested(&ctx->mutex, nesting);
1115 if (event->ctx != ctx) {
1116 mutex_unlock(&ctx->mutex);
1124 static inline struct perf_event_context *
1125 perf_event_ctx_lock(struct perf_event *event)
1127 return perf_event_ctx_lock_nested(event, 0);
1130 static void perf_event_ctx_unlock(struct perf_event *event,
1131 struct perf_event_context *ctx)
1133 mutex_unlock(&ctx->mutex);
1138 * This must be done under the ctx->lock, such as to serialize against
1139 * context_equiv(), therefore we cannot call put_ctx() since that might end up
1140 * calling scheduler related locks and ctx->lock nests inside those.
1142 static __must_check struct perf_event_context *
1143 unclone_ctx(struct perf_event_context *ctx)
1145 struct perf_event_context *parent_ctx = ctx->parent_ctx;
1147 lockdep_assert_held(&ctx->lock);
1150 ctx->parent_ctx = NULL;
1156 static u32 perf_event_pid(struct perf_event *event, struct task_struct *p)
1159 * only top level events have the pid namespace they were created in
1162 event = event->parent;
1164 return task_tgid_nr_ns(p, event->ns);
1167 static u32 perf_event_tid(struct perf_event *event, struct task_struct *p)
1170 * only top level events have the pid namespace they were created in
1173 event = event->parent;
1175 return task_pid_nr_ns(p, event->ns);
1179 * If we inherit events we want to return the parent event id
1182 static u64 primary_event_id(struct perf_event *event)
1187 id = event->parent->id;
1193 * Get the perf_event_context for a task and lock it.
1195 * This has to cope with with the fact that until it is locked,
1196 * the context could get moved to another task.
1198 static struct perf_event_context *
1199 perf_lock_task_context(struct task_struct *task, int ctxn, unsigned long *flags)
1201 struct perf_event_context *ctx;
1205 * One of the few rules of preemptible RCU is that one cannot do
1206 * rcu_read_unlock() while holding a scheduler (or nested) lock when
1207 * part of the read side critical section was irqs-enabled -- see
1208 * rcu_read_unlock_special().
1210 * Since ctx->lock nests under rq->lock we must ensure the entire read
1211 * side critical section has interrupts disabled.
1213 local_irq_save(*flags);
1215 ctx = rcu_dereference(task->perf_event_ctxp[ctxn]);
1218 * If this context is a clone of another, it might
1219 * get swapped for another underneath us by
1220 * perf_event_task_sched_out, though the
1221 * rcu_read_lock() protects us from any context
1222 * getting freed. Lock the context and check if it
1223 * got swapped before we could get the lock, and retry
1224 * if so. If we locked the right context, then it
1225 * can't get swapped on us any more.
1227 raw_spin_lock(&ctx->lock);
1228 if (ctx != rcu_dereference(task->perf_event_ctxp[ctxn])) {
1229 raw_spin_unlock(&ctx->lock);
1231 local_irq_restore(*flags);
1235 if (ctx->task == TASK_TOMBSTONE ||
1236 !atomic_inc_not_zero(&ctx->refcount)) {
1237 raw_spin_unlock(&ctx->lock);
1240 WARN_ON_ONCE(ctx->task != task);
1245 local_irq_restore(*flags);
1250 * Get the context for a task and increment its pin_count so it
1251 * can't get swapped to another task. This also increments its
1252 * reference count so that the context can't get freed.
1254 static struct perf_event_context *
1255 perf_pin_task_context(struct task_struct *task, int ctxn)
1257 struct perf_event_context *ctx;
1258 unsigned long flags;
1260 ctx = perf_lock_task_context(task, ctxn, &flags);
1263 raw_spin_unlock_irqrestore(&ctx->lock, flags);
1268 static void perf_unpin_context(struct perf_event_context *ctx)
1270 unsigned long flags;
1272 raw_spin_lock_irqsave(&ctx->lock, flags);
1274 raw_spin_unlock_irqrestore(&ctx->lock, flags);
1278 * Update the record of the current time in a context.
1280 static void update_context_time(struct perf_event_context *ctx)
1282 u64 now = perf_clock();
1284 ctx->time += now - ctx->timestamp;
1285 ctx->timestamp = now;
1288 static u64 perf_event_time(struct perf_event *event)
1290 struct perf_event_context *ctx = event->ctx;
1292 if (is_cgroup_event(event))
1293 return perf_cgroup_event_time(event);
1295 return ctx ? ctx->time : 0;
1299 * Update the total_time_enabled and total_time_running fields for a event.
1301 static void update_event_times(struct perf_event *event)
1303 struct perf_event_context *ctx = event->ctx;
1306 lockdep_assert_held(&ctx->lock);
1308 if (event->state < PERF_EVENT_STATE_INACTIVE ||
1309 event->group_leader->state < PERF_EVENT_STATE_INACTIVE)
1313 * in cgroup mode, time_enabled represents
1314 * the time the event was enabled AND active
1315 * tasks were in the monitored cgroup. This is
1316 * independent of the activity of the context as
1317 * there may be a mix of cgroup and non-cgroup events.
1319 * That is why we treat cgroup events differently
1322 if (is_cgroup_event(event))
1323 run_end = perf_cgroup_event_time(event);
1324 else if (ctx->is_active)
1325 run_end = ctx->time;
1327 run_end = event->tstamp_stopped;
1329 event->total_time_enabled = run_end - event->tstamp_enabled;
1331 if (event->state == PERF_EVENT_STATE_INACTIVE)
1332 run_end = event->tstamp_stopped;
1334 run_end = perf_event_time(event);
1336 event->total_time_running = run_end - event->tstamp_running;
1341 * Update total_time_enabled and total_time_running for all events in a group.
1343 static void update_group_times(struct perf_event *leader)
1345 struct perf_event *event;
1347 update_event_times(leader);
1348 list_for_each_entry(event, &leader->sibling_list, group_entry)
1349 update_event_times(event);
1352 static struct list_head *
1353 ctx_group_list(struct perf_event *event, struct perf_event_context *ctx)
1355 if (event->attr.pinned)
1356 return &ctx->pinned_groups;
1358 return &ctx->flexible_groups;
1362 * Add a event from the lists for its context.
1363 * Must be called with ctx->mutex and ctx->lock held.
1366 list_add_event(struct perf_event *event, struct perf_event_context *ctx)
1368 lockdep_assert_held(&ctx->lock);
1370 WARN_ON_ONCE(event->attach_state & PERF_ATTACH_CONTEXT);
1371 event->attach_state |= PERF_ATTACH_CONTEXT;
1374 * If we're a stand alone event or group leader, we go to the context
1375 * list, group events are kept attached to the group so that
1376 * perf_group_detach can, at all times, locate all siblings.
1378 if (event->group_leader == event) {
1379 struct list_head *list;
1381 if (is_software_event(event))
1382 event->group_flags |= PERF_GROUP_SOFTWARE;
1384 list = ctx_group_list(event, ctx);
1385 list_add_tail(&event->group_entry, list);
1388 if (is_cgroup_event(event))
1391 list_add_rcu(&event->event_entry, &ctx->event_list);
1393 if (event->attr.inherit_stat)
1400 * Initialize event state based on the perf_event_attr::disabled.
1402 static inline void perf_event__state_init(struct perf_event *event)
1404 event->state = event->attr.disabled ? PERF_EVENT_STATE_OFF :
1405 PERF_EVENT_STATE_INACTIVE;
1408 static void __perf_event_read_size(struct perf_event *event, int nr_siblings)
1410 int entry = sizeof(u64); /* value */
1414 if (event->attr.read_format & PERF_FORMAT_TOTAL_TIME_ENABLED)
1415 size += sizeof(u64);
1417 if (event->attr.read_format & PERF_FORMAT_TOTAL_TIME_RUNNING)
1418 size += sizeof(u64);
1420 if (event->attr.read_format & PERF_FORMAT_ID)
1421 entry += sizeof(u64);
1423 if (event->attr.read_format & PERF_FORMAT_GROUP) {
1425 size += sizeof(u64);
1429 event->read_size = size;
1432 static void __perf_event_header_size(struct perf_event *event, u64 sample_type)
1434 struct perf_sample_data *data;
1437 if (sample_type & PERF_SAMPLE_IP)
1438 size += sizeof(data->ip);
1440 if (sample_type & PERF_SAMPLE_ADDR)
1441 size += sizeof(data->addr);
1443 if (sample_type & PERF_SAMPLE_PERIOD)
1444 size += sizeof(data->period);
1446 if (sample_type & PERF_SAMPLE_WEIGHT)
1447 size += sizeof(data->weight);
1449 if (sample_type & PERF_SAMPLE_READ)
1450 size += event->read_size;
1452 if (sample_type & PERF_SAMPLE_DATA_SRC)
1453 size += sizeof(data->data_src.val);
1455 if (sample_type & PERF_SAMPLE_TRANSACTION)
1456 size += sizeof(data->txn);
1458 event->header_size = size;
1462 * Called at perf_event creation and when events are attached/detached from a
1465 static void perf_event__header_size(struct perf_event *event)
1467 __perf_event_read_size(event,
1468 event->group_leader->nr_siblings);
1469 __perf_event_header_size(event, event->attr.sample_type);
1472 static void perf_event__id_header_size(struct perf_event *event)
1474 struct perf_sample_data *data;
1475 u64 sample_type = event->attr.sample_type;
1478 if (sample_type & PERF_SAMPLE_TID)
1479 size += sizeof(data->tid_entry);
1481 if (sample_type & PERF_SAMPLE_TIME)
1482 size += sizeof(data->time);
1484 if (sample_type & PERF_SAMPLE_IDENTIFIER)
1485 size += sizeof(data->id);
1487 if (sample_type & PERF_SAMPLE_ID)
1488 size += sizeof(data->id);
1490 if (sample_type & PERF_SAMPLE_STREAM_ID)
1491 size += sizeof(data->stream_id);
1493 if (sample_type & PERF_SAMPLE_CPU)
1494 size += sizeof(data->cpu_entry);
1496 event->id_header_size = size;
1499 static bool perf_event_validate_size(struct perf_event *event)
1502 * The values computed here will be over-written when we actually
1505 __perf_event_read_size(event, event->group_leader->nr_siblings + 1);
1506 __perf_event_header_size(event, event->attr.sample_type & ~PERF_SAMPLE_READ);
1507 perf_event__id_header_size(event);
1510 * Sum the lot; should not exceed the 64k limit we have on records.
1511 * Conservative limit to allow for callchains and other variable fields.
1513 if (event->read_size + event->header_size +
1514 event->id_header_size + sizeof(struct perf_event_header) >= 16*1024)
1520 static void perf_group_attach(struct perf_event *event)
1522 struct perf_event *group_leader = event->group_leader, *pos;
1525 * We can have double attach due to group movement in perf_event_open.
1527 if (event->attach_state & PERF_ATTACH_GROUP)
1530 event->attach_state |= PERF_ATTACH_GROUP;
1532 if (group_leader == event)
1535 WARN_ON_ONCE(group_leader->ctx != event->ctx);
1537 if (group_leader->group_flags & PERF_GROUP_SOFTWARE &&
1538 !is_software_event(event))
1539 group_leader->group_flags &= ~PERF_GROUP_SOFTWARE;
1541 list_add_tail(&event->group_entry, &group_leader->sibling_list);
1542 group_leader->nr_siblings++;
1544 perf_event__header_size(group_leader);
1546 list_for_each_entry(pos, &group_leader->sibling_list, group_entry)
1547 perf_event__header_size(pos);
1551 * Remove a event from the lists for its context.
1552 * Must be called with ctx->mutex and ctx->lock held.
1555 list_del_event(struct perf_event *event, struct perf_event_context *ctx)
1557 struct perf_cpu_context *cpuctx;
1559 WARN_ON_ONCE(event->ctx != ctx);
1560 lockdep_assert_held(&ctx->lock);
1563 * We can have double detach due to exit/hot-unplug + close.
1565 if (!(event->attach_state & PERF_ATTACH_CONTEXT))
1568 event->attach_state &= ~PERF_ATTACH_CONTEXT;
1570 if (is_cgroup_event(event)) {
1573 * Because cgroup events are always per-cpu events, this will
1574 * always be called from the right CPU.
1576 cpuctx = __get_cpu_context(ctx);
1578 * If there are no more cgroup events then clear cgrp to avoid
1579 * stale pointer in update_cgrp_time_from_cpuctx().
1581 if (!ctx->nr_cgroups)
1582 cpuctx->cgrp = NULL;
1586 if (event->attr.inherit_stat)
1589 list_del_rcu(&event->event_entry);
1591 if (event->group_leader == event)
1592 list_del_init(&event->group_entry);
1594 update_group_times(event);
1597 * If event was in error state, then keep it
1598 * that way, otherwise bogus counts will be
1599 * returned on read(). The only way to get out
1600 * of error state is by explicit re-enabling
1603 if (event->state > PERF_EVENT_STATE_OFF)
1604 event->state = PERF_EVENT_STATE_OFF;
1609 static void perf_group_detach(struct perf_event *event)
1611 struct perf_event *sibling, *tmp;
1612 struct list_head *list = NULL;
1615 * We can have double detach due to exit/hot-unplug + close.
1617 if (!(event->attach_state & PERF_ATTACH_GROUP))
1620 event->attach_state &= ~PERF_ATTACH_GROUP;
1623 * If this is a sibling, remove it from its group.
1625 if (event->group_leader != event) {
1626 list_del_init(&event->group_entry);
1627 event->group_leader->nr_siblings--;
1631 if (!list_empty(&event->group_entry))
1632 list = &event->group_entry;
1635 * If this was a group event with sibling events then
1636 * upgrade the siblings to singleton events by adding them
1637 * to whatever list we are on.
1639 list_for_each_entry_safe(sibling, tmp, &event->sibling_list, group_entry) {
1641 list_move_tail(&sibling->group_entry, list);
1642 sibling->group_leader = sibling;
1644 /* Inherit group flags from the previous leader */
1645 sibling->group_flags = event->group_flags;
1647 WARN_ON_ONCE(sibling->ctx != event->ctx);
1651 perf_event__header_size(event->group_leader);
1653 list_for_each_entry(tmp, &event->group_leader->sibling_list, group_entry)
1654 perf_event__header_size(tmp);
1657 static bool is_orphaned_event(struct perf_event *event)
1659 return event->state == PERF_EVENT_STATE_DEAD;
1662 static inline int pmu_filter_match(struct perf_event *event)
1664 struct pmu *pmu = event->pmu;
1665 return pmu->filter_match ? pmu->filter_match(event) : 1;
1669 event_filter_match(struct perf_event *event)
1671 return (event->cpu == -1 || event->cpu == smp_processor_id())
1672 && perf_cgroup_match(event) && pmu_filter_match(event);
1676 event_sched_out(struct perf_event *event,
1677 struct perf_cpu_context *cpuctx,
1678 struct perf_event_context *ctx)
1680 u64 tstamp = perf_event_time(event);
1683 WARN_ON_ONCE(event->ctx != ctx);
1684 lockdep_assert_held(&ctx->lock);
1687 * An event which could not be activated because of
1688 * filter mismatch still needs to have its timings
1689 * maintained, otherwise bogus information is return
1690 * via read() for time_enabled, time_running:
1692 if (event->state == PERF_EVENT_STATE_INACTIVE
1693 && !event_filter_match(event)) {
1694 delta = tstamp - event->tstamp_stopped;
1695 event->tstamp_running += delta;
1696 event->tstamp_stopped = tstamp;
1699 if (event->state != PERF_EVENT_STATE_ACTIVE)
1702 perf_pmu_disable(event->pmu);
1704 event->tstamp_stopped = tstamp;
1705 event->pmu->del(event, 0);
1707 event->state = PERF_EVENT_STATE_INACTIVE;
1708 if (event->pending_disable) {
1709 event->pending_disable = 0;
1710 event->state = PERF_EVENT_STATE_OFF;
1713 if (!is_software_event(event))
1714 cpuctx->active_oncpu--;
1715 if (!--ctx->nr_active)
1716 perf_event_ctx_deactivate(ctx);
1717 if (event->attr.freq && event->attr.sample_freq)
1719 if (event->attr.exclusive || !cpuctx->active_oncpu)
1720 cpuctx->exclusive = 0;
1722 perf_pmu_enable(event->pmu);
1726 group_sched_out(struct perf_event *group_event,
1727 struct perf_cpu_context *cpuctx,
1728 struct perf_event_context *ctx)
1730 struct perf_event *event;
1731 int state = group_event->state;
1733 event_sched_out(group_event, cpuctx, ctx);
1736 * Schedule out siblings (if any):
1738 list_for_each_entry(event, &group_event->sibling_list, group_entry)
1739 event_sched_out(event, cpuctx, ctx);
1741 if (state == PERF_EVENT_STATE_ACTIVE && group_event->attr.exclusive)
1742 cpuctx->exclusive = 0;
1745 #define DETACH_GROUP 0x01UL
1748 * Cross CPU call to remove a performance event
1750 * We disable the event on the hardware level first. After that we
1751 * remove it from the context list.
1754 __perf_remove_from_context(struct perf_event *event,
1755 struct perf_cpu_context *cpuctx,
1756 struct perf_event_context *ctx,
1759 unsigned long flags = (unsigned long)info;
1761 event_sched_out(event, cpuctx, ctx);
1762 if (flags & DETACH_GROUP)
1763 perf_group_detach(event);
1764 list_del_event(event, ctx);
1766 if (!ctx->nr_events && ctx->is_active) {
1769 WARN_ON_ONCE(cpuctx->task_ctx != ctx);
1770 cpuctx->task_ctx = NULL;
1776 * Remove the event from a task's (or a CPU's) list of events.
1778 * If event->ctx is a cloned context, callers must make sure that
1779 * every task struct that event->ctx->task could possibly point to
1780 * remains valid. This is OK when called from perf_release since
1781 * that only calls us on the top-level context, which can't be a clone.
1782 * When called from perf_event_exit_task, it's OK because the
1783 * context has been detached from its task.
1785 static void perf_remove_from_context(struct perf_event *event, unsigned long flags)
1787 lockdep_assert_held(&event->ctx->mutex);
1789 event_function_call(event, __perf_remove_from_context, (void *)flags);
1793 * Cross CPU call to disable a performance event
1795 static void __perf_event_disable(struct perf_event *event,
1796 struct perf_cpu_context *cpuctx,
1797 struct perf_event_context *ctx,
1800 if (event->state < PERF_EVENT_STATE_INACTIVE)
1803 update_context_time(ctx);
1804 update_cgrp_time_from_event(event);
1805 update_group_times(event);
1806 if (event == event->group_leader)
1807 group_sched_out(event, cpuctx, ctx);
1809 event_sched_out(event, cpuctx, ctx);
1810 event->state = PERF_EVENT_STATE_OFF;
1816 * If event->ctx is a cloned context, callers must make sure that
1817 * every task struct that event->ctx->task could possibly point to
1818 * remains valid. This condition is satisifed when called through
1819 * perf_event_for_each_child or perf_event_for_each because they
1820 * hold the top-level event's child_mutex, so any descendant that
1821 * goes to exit will block in perf_event_exit_event().
1823 * When called from perf_pending_event it's OK because event->ctx
1824 * is the current context on this CPU and preemption is disabled,
1825 * hence we can't get into perf_event_task_sched_out for this context.
1827 static void _perf_event_disable(struct perf_event *event)
1829 struct perf_event_context *ctx = event->ctx;
1831 raw_spin_lock_irq(&ctx->lock);
1832 if (event->state <= PERF_EVENT_STATE_OFF) {
1833 raw_spin_unlock_irq(&ctx->lock);
1836 raw_spin_unlock_irq(&ctx->lock);
1838 event_function_call(event, __perf_event_disable, NULL);
1841 void perf_event_disable_local(struct perf_event *event)
1843 event_function_local(event, __perf_event_disable, NULL);
1847 * Strictly speaking kernel users cannot create groups and therefore this
1848 * interface does not need the perf_event_ctx_lock() magic.
1850 void perf_event_disable(struct perf_event *event)
1852 struct perf_event_context *ctx;
1854 ctx = perf_event_ctx_lock(event);
1855 _perf_event_disable(event);
1856 perf_event_ctx_unlock(event, ctx);
1858 EXPORT_SYMBOL_GPL(perf_event_disable);
1860 static void perf_set_shadow_time(struct perf_event *event,
1861 struct perf_event_context *ctx,
1865 * use the correct time source for the time snapshot
1867 * We could get by without this by leveraging the
1868 * fact that to get to this function, the caller
1869 * has most likely already called update_context_time()
1870 * and update_cgrp_time_xx() and thus both timestamp
1871 * are identical (or very close). Given that tstamp is,
1872 * already adjusted for cgroup, we could say that:
1873 * tstamp - ctx->timestamp
1875 * tstamp - cgrp->timestamp.
1877 * Then, in perf_output_read(), the calculation would
1878 * work with no changes because:
1879 * - event is guaranteed scheduled in
1880 * - no scheduled out in between
1881 * - thus the timestamp would be the same
1883 * But this is a bit hairy.
1885 * So instead, we have an explicit cgroup call to remain
1886 * within the time time source all along. We believe it
1887 * is cleaner and simpler to understand.
1889 if (is_cgroup_event(event))
1890 perf_cgroup_set_shadow_time(event, tstamp);
1892 event->shadow_ctx_time = tstamp - ctx->timestamp;
1895 #define MAX_INTERRUPTS (~0ULL)
1897 static void perf_log_throttle(struct perf_event *event, int enable);
1898 static void perf_log_itrace_start(struct perf_event *event);
1901 event_sched_in(struct perf_event *event,
1902 struct perf_cpu_context *cpuctx,
1903 struct perf_event_context *ctx)
1905 u64 tstamp = perf_event_time(event);
1908 lockdep_assert_held(&ctx->lock);
1910 if (event->state <= PERF_EVENT_STATE_OFF)
1913 event->state = PERF_EVENT_STATE_ACTIVE;
1914 event->oncpu = smp_processor_id();
1917 * Unthrottle events, since we scheduled we might have missed several
1918 * ticks already, also for a heavily scheduling task there is little
1919 * guarantee it'll get a tick in a timely manner.
1921 if (unlikely(event->hw.interrupts == MAX_INTERRUPTS)) {
1922 perf_log_throttle(event, 1);
1923 event->hw.interrupts = 0;
1927 * The new state must be visible before we turn it on in the hardware:
1931 perf_pmu_disable(event->pmu);
1933 perf_set_shadow_time(event, ctx, tstamp);
1935 perf_log_itrace_start(event);
1937 if (event->pmu->add(event, PERF_EF_START)) {
1938 event->state = PERF_EVENT_STATE_INACTIVE;
1944 event->tstamp_running += tstamp - event->tstamp_stopped;
1946 if (!is_software_event(event))
1947 cpuctx->active_oncpu++;
1948 if (!ctx->nr_active++)
1949 perf_event_ctx_activate(ctx);
1950 if (event->attr.freq && event->attr.sample_freq)
1953 if (event->attr.exclusive)
1954 cpuctx->exclusive = 1;
1957 perf_pmu_enable(event->pmu);
1963 group_sched_in(struct perf_event *group_event,
1964 struct perf_cpu_context *cpuctx,
1965 struct perf_event_context *ctx)
1967 struct perf_event *event, *partial_group = NULL;
1968 struct pmu *pmu = ctx->pmu;
1969 u64 now = ctx->time;
1970 bool simulate = false;
1972 if (group_event->state == PERF_EVENT_STATE_OFF)
1975 pmu->start_txn(pmu, PERF_PMU_TXN_ADD);
1977 if (event_sched_in(group_event, cpuctx, ctx)) {
1978 pmu->cancel_txn(pmu);
1979 perf_mux_hrtimer_restart(cpuctx);
1984 * Schedule in siblings as one group (if any):
1986 list_for_each_entry(event, &group_event->sibling_list, group_entry) {
1987 if (event_sched_in(event, cpuctx, ctx)) {
1988 partial_group = event;
1993 if (!pmu->commit_txn(pmu))
1998 * Groups can be scheduled in as one unit only, so undo any
1999 * partial group before returning:
2000 * The events up to the failed event are scheduled out normally,
2001 * tstamp_stopped will be updated.
2003 * The failed events and the remaining siblings need to have
2004 * their timings updated as if they had gone thru event_sched_in()
2005 * and event_sched_out(). This is required to get consistent timings
2006 * across the group. This also takes care of the case where the group
2007 * could never be scheduled by ensuring tstamp_stopped is set to mark
2008 * the time the event was actually stopped, such that time delta
2009 * calculation in update_event_times() is correct.
2011 list_for_each_entry(event, &group_event->sibling_list, group_entry) {
2012 if (event == partial_group)
2016 event->tstamp_running += now - event->tstamp_stopped;
2017 event->tstamp_stopped = now;
2019 event_sched_out(event, cpuctx, ctx);
2022 event_sched_out(group_event, cpuctx, ctx);
2024 pmu->cancel_txn(pmu);
2026 perf_mux_hrtimer_restart(cpuctx);
2032 * Work out whether we can put this event group on the CPU now.
2034 static int group_can_go_on(struct perf_event *event,
2035 struct perf_cpu_context *cpuctx,
2039 * Groups consisting entirely of software events can always go on.
2041 if (event->group_flags & PERF_GROUP_SOFTWARE)
2044 * If an exclusive group is already on, no other hardware
2047 if (cpuctx->exclusive)
2050 * If this group is exclusive and there are already
2051 * events on the CPU, it can't go on.
2053 if (event->attr.exclusive && cpuctx->active_oncpu)
2056 * Otherwise, try to add it if all previous groups were able
2062 static void add_event_to_ctx(struct perf_event *event,
2063 struct perf_event_context *ctx)
2065 u64 tstamp = perf_event_time(event);
2067 list_add_event(event, ctx);
2068 perf_group_attach(event);
2069 event->tstamp_enabled = tstamp;
2070 event->tstamp_running = tstamp;
2071 event->tstamp_stopped = tstamp;
2074 static void ctx_sched_out(struct perf_event_context *ctx,
2075 struct perf_cpu_context *cpuctx,
2076 enum event_type_t event_type);
2078 ctx_sched_in(struct perf_event_context *ctx,
2079 struct perf_cpu_context *cpuctx,
2080 enum event_type_t event_type,
2081 struct task_struct *task);
2083 static void task_ctx_sched_out(struct perf_cpu_context *cpuctx,
2084 struct perf_event_context *ctx)
2086 if (!cpuctx->task_ctx)
2089 if (WARN_ON_ONCE(ctx != cpuctx->task_ctx))
2092 ctx_sched_out(ctx, cpuctx, EVENT_ALL);
2095 static void perf_event_sched_in(struct perf_cpu_context *cpuctx,
2096 struct perf_event_context *ctx,
2097 struct task_struct *task)
2099 cpu_ctx_sched_in(cpuctx, EVENT_PINNED, task);
2101 ctx_sched_in(ctx, cpuctx, EVENT_PINNED, task);
2102 cpu_ctx_sched_in(cpuctx, EVENT_FLEXIBLE, task);
2104 ctx_sched_in(ctx, cpuctx, EVENT_FLEXIBLE, task);
2107 static void ctx_resched(struct perf_cpu_context *cpuctx,
2108 struct perf_event_context *task_ctx)
2110 perf_pmu_disable(cpuctx->ctx.pmu);
2112 task_ctx_sched_out(cpuctx, task_ctx);
2113 cpu_ctx_sched_out(cpuctx, EVENT_ALL);
2114 perf_event_sched_in(cpuctx, task_ctx, current);
2115 perf_pmu_enable(cpuctx->ctx.pmu);
2119 * Cross CPU call to install and enable a performance event
2121 * Very similar to remote_function() + event_function() but cannot assume that
2122 * things like ctx->is_active and cpuctx->task_ctx are set.
2124 static int __perf_install_in_context(void *info)
2126 struct perf_event *event = info;
2127 struct perf_event_context *ctx = event->ctx;
2128 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
2129 struct perf_event_context *task_ctx = cpuctx->task_ctx;
2130 bool activate = true;
2133 raw_spin_lock(&cpuctx->ctx.lock);
2135 raw_spin_lock(&ctx->lock);
2138 /* If we're on the wrong CPU, try again */
2139 if (task_cpu(ctx->task) != smp_processor_id()) {
2145 * If we're on the right CPU, see if the task we target is
2146 * current, if not we don't have to activate the ctx, a future
2147 * context switch will do that for us.
2149 if (ctx->task != current)
2152 WARN_ON_ONCE(cpuctx->task_ctx && cpuctx->task_ctx != ctx);
2154 } else if (task_ctx) {
2155 raw_spin_lock(&task_ctx->lock);
2159 ctx_sched_out(ctx, cpuctx, EVENT_TIME);
2160 add_event_to_ctx(event, ctx);
2161 ctx_resched(cpuctx, task_ctx);
2163 add_event_to_ctx(event, ctx);
2167 perf_ctx_unlock(cpuctx, task_ctx);
2173 * Attach a performance event to a context.
2175 * Very similar to event_function_call, see comment there.
2178 perf_install_in_context(struct perf_event_context *ctx,
2179 struct perf_event *event,
2182 struct task_struct *task = READ_ONCE(ctx->task);
2184 lockdep_assert_held(&ctx->mutex);
2187 if (event->cpu != -1)
2191 cpu_function_call(cpu, __perf_install_in_context, event);
2196 * Should not happen, we validate the ctx is still alive before calling.
2198 if (WARN_ON_ONCE(task == TASK_TOMBSTONE))
2202 * Installing events is tricky because we cannot rely on ctx->is_active
2203 * to be set in case this is the nr_events 0 -> 1 transition.
2207 * Cannot use task_function_call() because we need to run on the task's
2208 * CPU regardless of whether its current or not.
2210 if (!cpu_function_call(task_cpu(task), __perf_install_in_context, event))
2213 raw_spin_lock_irq(&ctx->lock);
2215 if (WARN_ON_ONCE(task == TASK_TOMBSTONE)) {
2217 * Cannot happen because we already checked above (which also
2218 * cannot happen), and we hold ctx->mutex, which serializes us
2219 * against perf_event_exit_task_context().
2221 raw_spin_unlock_irq(&ctx->lock);
2224 raw_spin_unlock_irq(&ctx->lock);
2226 * Since !ctx->is_active doesn't mean anything, we must IPI
2233 * Put a event into inactive state and update time fields.
2234 * Enabling the leader of a group effectively enables all
2235 * the group members that aren't explicitly disabled, so we
2236 * have to update their ->tstamp_enabled also.
2237 * Note: this works for group members as well as group leaders
2238 * since the non-leader members' sibling_lists will be empty.
2240 static void __perf_event_mark_enabled(struct perf_event *event)
2242 struct perf_event *sub;
2243 u64 tstamp = perf_event_time(event);
2245 event->state = PERF_EVENT_STATE_INACTIVE;
2246 event->tstamp_enabled = tstamp - event->total_time_enabled;
2247 list_for_each_entry(sub, &event->sibling_list, group_entry) {
2248 if (sub->state >= PERF_EVENT_STATE_INACTIVE)
2249 sub->tstamp_enabled = tstamp - sub->total_time_enabled;
2254 * Cross CPU call to enable a performance event
2256 static void __perf_event_enable(struct perf_event *event,
2257 struct perf_cpu_context *cpuctx,
2258 struct perf_event_context *ctx,
2261 struct perf_event *leader = event->group_leader;
2262 struct perf_event_context *task_ctx;
2264 if (event->state >= PERF_EVENT_STATE_INACTIVE ||
2265 event->state <= PERF_EVENT_STATE_ERROR)
2269 ctx_sched_out(ctx, cpuctx, EVENT_TIME);
2271 __perf_event_mark_enabled(event);
2273 if (!ctx->is_active)
2276 if (!event_filter_match(event)) {
2277 if (is_cgroup_event(event))
2278 perf_cgroup_defer_enabled(event);
2279 ctx_sched_in(ctx, cpuctx, EVENT_TIME, current);
2284 * If the event is in a group and isn't the group leader,
2285 * then don't put it on unless the group is on.
2287 if (leader != event && leader->state != PERF_EVENT_STATE_ACTIVE) {
2288 ctx_sched_in(ctx, cpuctx, EVENT_TIME, current);
2292 task_ctx = cpuctx->task_ctx;
2294 WARN_ON_ONCE(task_ctx != ctx);
2296 ctx_resched(cpuctx, task_ctx);
2302 * If event->ctx is a cloned context, callers must make sure that
2303 * every task struct that event->ctx->task could possibly point to
2304 * remains valid. This condition is satisfied when called through
2305 * perf_event_for_each_child or perf_event_for_each as described
2306 * for perf_event_disable.
2308 static void _perf_event_enable(struct perf_event *event)
2310 struct perf_event_context *ctx = event->ctx;
2312 raw_spin_lock_irq(&ctx->lock);
2313 if (event->state >= PERF_EVENT_STATE_INACTIVE ||
2314 event->state < PERF_EVENT_STATE_ERROR) {
2315 raw_spin_unlock_irq(&ctx->lock);
2320 * If the event is in error state, clear that first.
2322 * That way, if we see the event in error state below, we know that it
2323 * has gone back into error state, as distinct from the task having
2324 * been scheduled away before the cross-call arrived.
2326 if (event->state == PERF_EVENT_STATE_ERROR)
2327 event->state = PERF_EVENT_STATE_OFF;
2328 raw_spin_unlock_irq(&ctx->lock);
2330 event_function_call(event, __perf_event_enable, NULL);
2334 * See perf_event_disable();
2336 void perf_event_enable(struct perf_event *event)
2338 struct perf_event_context *ctx;
2340 ctx = perf_event_ctx_lock(event);
2341 _perf_event_enable(event);
2342 perf_event_ctx_unlock(event, ctx);
2344 EXPORT_SYMBOL_GPL(perf_event_enable);
2346 static int _perf_event_refresh(struct perf_event *event, int refresh)
2349 * not supported on inherited events
2351 if (event->attr.inherit || !is_sampling_event(event))
2354 atomic_add(refresh, &event->event_limit);
2355 _perf_event_enable(event);
2361 * See perf_event_disable()
2363 int perf_event_refresh(struct perf_event *event, int refresh)
2365 struct perf_event_context *ctx;
2368 ctx = perf_event_ctx_lock(event);
2369 ret = _perf_event_refresh(event, refresh);
2370 perf_event_ctx_unlock(event, ctx);
2374 EXPORT_SYMBOL_GPL(perf_event_refresh);
2376 static void ctx_sched_out(struct perf_event_context *ctx,
2377 struct perf_cpu_context *cpuctx,
2378 enum event_type_t event_type)
2380 int is_active = ctx->is_active;
2381 struct perf_event *event;
2383 lockdep_assert_held(&ctx->lock);
2385 if (likely(!ctx->nr_events)) {
2387 * See __perf_remove_from_context().
2389 WARN_ON_ONCE(ctx->is_active);
2391 WARN_ON_ONCE(cpuctx->task_ctx);
2395 ctx->is_active &= ~event_type;
2396 if (!(ctx->is_active & EVENT_ALL))
2400 WARN_ON_ONCE(cpuctx->task_ctx != ctx);
2401 if (!ctx->is_active)
2402 cpuctx->task_ctx = NULL;
2405 is_active ^= ctx->is_active; /* changed bits */
2407 if (is_active & EVENT_TIME) {
2408 /* update (and stop) ctx time */
2409 update_context_time(ctx);
2410 update_cgrp_time_from_cpuctx(cpuctx);
2413 if (!ctx->nr_active || !(is_active & EVENT_ALL))
2416 perf_pmu_disable(ctx->pmu);
2417 if (is_active & EVENT_PINNED) {
2418 list_for_each_entry(event, &ctx->pinned_groups, group_entry)
2419 group_sched_out(event, cpuctx, ctx);
2422 if (is_active & EVENT_FLEXIBLE) {
2423 list_for_each_entry(event, &ctx->flexible_groups, group_entry)
2424 group_sched_out(event, cpuctx, ctx);
2426 perf_pmu_enable(ctx->pmu);
2430 * Test whether two contexts are equivalent, i.e. whether they have both been
2431 * cloned from the same version of the same context.
2433 * Equivalence is measured using a generation number in the context that is
2434 * incremented on each modification to it; see unclone_ctx(), list_add_event()
2435 * and list_del_event().
2437 static int context_equiv(struct perf_event_context *ctx1,
2438 struct perf_event_context *ctx2)
2440 lockdep_assert_held(&ctx1->lock);
2441 lockdep_assert_held(&ctx2->lock);
2443 /* Pinning disables the swap optimization */
2444 if (ctx1->pin_count || ctx2->pin_count)
2447 /* If ctx1 is the parent of ctx2 */
2448 if (ctx1 == ctx2->parent_ctx && ctx1->generation == ctx2->parent_gen)
2451 /* If ctx2 is the parent of ctx1 */
2452 if (ctx1->parent_ctx == ctx2 && ctx1->parent_gen == ctx2->generation)
2456 * If ctx1 and ctx2 have the same parent; we flatten the parent
2457 * hierarchy, see perf_event_init_context().
2459 if (ctx1->parent_ctx && ctx1->parent_ctx == ctx2->parent_ctx &&
2460 ctx1->parent_gen == ctx2->parent_gen)
2467 static void __perf_event_sync_stat(struct perf_event *event,
2468 struct perf_event *next_event)
2472 if (!event->attr.inherit_stat)
2476 * Update the event value, we cannot use perf_event_read()
2477 * because we're in the middle of a context switch and have IRQs
2478 * disabled, which upsets smp_call_function_single(), however
2479 * we know the event must be on the current CPU, therefore we
2480 * don't need to use it.
2482 switch (event->state) {
2483 case PERF_EVENT_STATE_ACTIVE:
2484 event->pmu->read(event);
2487 case PERF_EVENT_STATE_INACTIVE:
2488 update_event_times(event);
2496 * In order to keep per-task stats reliable we need to flip the event
2497 * values when we flip the contexts.
2499 value = local64_read(&next_event->count);
2500 value = local64_xchg(&event->count, value);
2501 local64_set(&next_event->count, value);
2503 swap(event->total_time_enabled, next_event->total_time_enabled);
2504 swap(event->total_time_running, next_event->total_time_running);
2507 * Since we swizzled the values, update the user visible data too.
2509 perf_event_update_userpage(event);
2510 perf_event_update_userpage(next_event);
2513 static void perf_event_sync_stat(struct perf_event_context *ctx,
2514 struct perf_event_context *next_ctx)
2516 struct perf_event *event, *next_event;
2521 update_context_time(ctx);
2523 event = list_first_entry(&ctx->event_list,
2524 struct perf_event, event_entry);
2526 next_event = list_first_entry(&next_ctx->event_list,
2527 struct perf_event, event_entry);
2529 while (&event->event_entry != &ctx->event_list &&
2530 &next_event->event_entry != &next_ctx->event_list) {
2532 __perf_event_sync_stat(event, next_event);
2534 event = list_next_entry(event, event_entry);
2535 next_event = list_next_entry(next_event, event_entry);
2539 static void perf_event_context_sched_out(struct task_struct *task, int ctxn,
2540 struct task_struct *next)
2542 struct perf_event_context *ctx = task->perf_event_ctxp[ctxn];
2543 struct perf_event_context *next_ctx;
2544 struct perf_event_context *parent, *next_parent;
2545 struct perf_cpu_context *cpuctx;
2551 cpuctx = __get_cpu_context(ctx);
2552 if (!cpuctx->task_ctx)
2556 next_ctx = next->perf_event_ctxp[ctxn];
2560 parent = rcu_dereference(ctx->parent_ctx);
2561 next_parent = rcu_dereference(next_ctx->parent_ctx);
2563 /* If neither context have a parent context; they cannot be clones. */
2564 if (!parent && !next_parent)
2567 if (next_parent == ctx || next_ctx == parent || next_parent == parent) {
2569 * Looks like the two contexts are clones, so we might be
2570 * able to optimize the context switch. We lock both
2571 * contexts and check that they are clones under the
2572 * lock (including re-checking that neither has been
2573 * uncloned in the meantime). It doesn't matter which
2574 * order we take the locks because no other cpu could
2575 * be trying to lock both of these tasks.
2577 raw_spin_lock(&ctx->lock);
2578 raw_spin_lock_nested(&next_ctx->lock, SINGLE_DEPTH_NESTING);
2579 if (context_equiv(ctx, next_ctx)) {
2580 WRITE_ONCE(ctx->task, next);
2581 WRITE_ONCE(next_ctx->task, task);
2583 swap(ctx->task_ctx_data, next_ctx->task_ctx_data);
2586 * RCU_INIT_POINTER here is safe because we've not
2587 * modified the ctx and the above modification of
2588 * ctx->task and ctx->task_ctx_data are immaterial
2589 * since those values are always verified under
2590 * ctx->lock which we're now holding.
2592 RCU_INIT_POINTER(task->perf_event_ctxp[ctxn], next_ctx);
2593 RCU_INIT_POINTER(next->perf_event_ctxp[ctxn], ctx);
2597 perf_event_sync_stat(ctx, next_ctx);
2599 raw_spin_unlock(&next_ctx->lock);
2600 raw_spin_unlock(&ctx->lock);
2606 raw_spin_lock(&ctx->lock);
2607 task_ctx_sched_out(cpuctx, ctx);
2608 raw_spin_unlock(&ctx->lock);
2612 void perf_sched_cb_dec(struct pmu *pmu)
2614 this_cpu_dec(perf_sched_cb_usages);
2617 void perf_sched_cb_inc(struct pmu *pmu)
2619 this_cpu_inc(perf_sched_cb_usages);
2623 * This function provides the context switch callback to the lower code
2624 * layer. It is invoked ONLY when the context switch callback is enabled.
2626 static void perf_pmu_sched_task(struct task_struct *prev,
2627 struct task_struct *next,
2630 struct perf_cpu_context *cpuctx;
2632 unsigned long flags;
2637 local_irq_save(flags);
2641 list_for_each_entry_rcu(pmu, &pmus, entry) {
2642 if (pmu->sched_task) {
2643 cpuctx = this_cpu_ptr(pmu->pmu_cpu_context);
2645 perf_ctx_lock(cpuctx, cpuctx->task_ctx);
2647 perf_pmu_disable(pmu);
2649 pmu->sched_task(cpuctx->task_ctx, sched_in);
2651 perf_pmu_enable(pmu);
2653 perf_ctx_unlock(cpuctx, cpuctx->task_ctx);
2659 local_irq_restore(flags);
2662 static void perf_event_switch(struct task_struct *task,
2663 struct task_struct *next_prev, bool sched_in);
2665 #define for_each_task_context_nr(ctxn) \
2666 for ((ctxn) = 0; (ctxn) < perf_nr_task_contexts; (ctxn)++)
2669 * Called from scheduler to remove the events of the current task,
2670 * with interrupts disabled.
2672 * We stop each event and update the event value in event->count.
2674 * This does not protect us against NMI, but disable()
2675 * sets the disabled bit in the control field of event _before_
2676 * accessing the event control register. If a NMI hits, then it will
2677 * not restart the event.
2679 void __perf_event_task_sched_out(struct task_struct *task,
2680 struct task_struct *next)
2684 if (__this_cpu_read(perf_sched_cb_usages))
2685 perf_pmu_sched_task(task, next, false);
2687 if (atomic_read(&nr_switch_events))
2688 perf_event_switch(task, next, false);
2690 for_each_task_context_nr(ctxn)
2691 perf_event_context_sched_out(task, ctxn, next);
2694 * if cgroup events exist on this CPU, then we need
2695 * to check if we have to switch out PMU state.
2696 * cgroup event are system-wide mode only
2698 if (atomic_read(this_cpu_ptr(&perf_cgroup_events)))
2699 perf_cgroup_sched_out(task, next);
2703 * Called with IRQs disabled
2705 static void cpu_ctx_sched_out(struct perf_cpu_context *cpuctx,
2706 enum event_type_t event_type)
2708 ctx_sched_out(&cpuctx->ctx, cpuctx, event_type);
2712 ctx_pinned_sched_in(struct perf_event_context *ctx,
2713 struct perf_cpu_context *cpuctx)
2715 struct perf_event *event;
2717 list_for_each_entry(event, &ctx->pinned_groups, group_entry) {
2718 if (event->state <= PERF_EVENT_STATE_OFF)
2720 if (!event_filter_match(event))
2723 /* may need to reset tstamp_enabled */
2724 if (is_cgroup_event(event))
2725 perf_cgroup_mark_enabled(event, ctx);
2727 if (group_can_go_on(event, cpuctx, 1))
2728 group_sched_in(event, cpuctx, ctx);
2731 * If this pinned group hasn't been scheduled,
2732 * put it in error state.
2734 if (event->state == PERF_EVENT_STATE_INACTIVE) {
2735 update_group_times(event);
2736 event->state = PERF_EVENT_STATE_ERROR;
2742 ctx_flexible_sched_in(struct perf_event_context *ctx,
2743 struct perf_cpu_context *cpuctx)
2745 struct perf_event *event;
2748 list_for_each_entry(event, &ctx->flexible_groups, group_entry) {
2749 /* Ignore events in OFF or ERROR state */
2750 if (event->state <= PERF_EVENT_STATE_OFF)
2753 * Listen to the 'cpu' scheduling filter constraint
2756 if (!event_filter_match(event))
2759 /* may need to reset tstamp_enabled */
2760 if (is_cgroup_event(event))
2761 perf_cgroup_mark_enabled(event, ctx);
2763 if (group_can_go_on(event, cpuctx, can_add_hw)) {
2764 if (group_sched_in(event, cpuctx, ctx))
2771 ctx_sched_in(struct perf_event_context *ctx,
2772 struct perf_cpu_context *cpuctx,
2773 enum event_type_t event_type,
2774 struct task_struct *task)
2776 int is_active = ctx->is_active;
2779 lockdep_assert_held(&ctx->lock);
2781 if (likely(!ctx->nr_events))
2784 ctx->is_active |= (event_type | EVENT_TIME);
2787 cpuctx->task_ctx = ctx;
2789 WARN_ON_ONCE(cpuctx->task_ctx != ctx);
2792 is_active ^= ctx->is_active; /* changed bits */
2794 if (is_active & EVENT_TIME) {
2795 /* start ctx time */
2797 ctx->timestamp = now;
2798 perf_cgroup_set_timestamp(task, ctx);
2802 * First go through the list and put on any pinned groups
2803 * in order to give them the best chance of going on.
2805 if (is_active & EVENT_PINNED)
2806 ctx_pinned_sched_in(ctx, cpuctx);
2808 /* Then walk through the lower prio flexible groups */
2809 if (is_active & EVENT_FLEXIBLE)
2810 ctx_flexible_sched_in(ctx, cpuctx);
2813 static void cpu_ctx_sched_in(struct perf_cpu_context *cpuctx,
2814 enum event_type_t event_type,
2815 struct task_struct *task)
2817 struct perf_event_context *ctx = &cpuctx->ctx;
2819 ctx_sched_in(ctx, cpuctx, event_type, task);
2822 static void perf_event_context_sched_in(struct perf_event_context *ctx,
2823 struct task_struct *task)
2825 struct perf_cpu_context *cpuctx;
2827 cpuctx = __get_cpu_context(ctx);
2828 if (cpuctx->task_ctx == ctx)
2831 perf_ctx_lock(cpuctx, ctx);
2832 perf_pmu_disable(ctx->pmu);
2834 * We want to keep the following priority order:
2835 * cpu pinned (that don't need to move), task pinned,
2836 * cpu flexible, task flexible.
2838 cpu_ctx_sched_out(cpuctx, EVENT_FLEXIBLE);
2839 perf_event_sched_in(cpuctx, ctx, task);
2840 perf_pmu_enable(ctx->pmu);
2841 perf_ctx_unlock(cpuctx, ctx);
2845 * Called from scheduler to add the events of the current task
2846 * with interrupts disabled.
2848 * We restore the event value and then enable it.
2850 * This does not protect us against NMI, but enable()
2851 * sets the enabled bit in the control field of event _before_
2852 * accessing the event control register. If a NMI hits, then it will
2853 * keep the event running.
2855 void __perf_event_task_sched_in(struct task_struct *prev,
2856 struct task_struct *task)
2858 struct perf_event_context *ctx;
2862 * If cgroup events exist on this CPU, then we need to check if we have
2863 * to switch in PMU state; cgroup event are system-wide mode only.
2865 * Since cgroup events are CPU events, we must schedule these in before
2866 * we schedule in the task events.
2868 if (atomic_read(this_cpu_ptr(&perf_cgroup_events)))
2869 perf_cgroup_sched_in(prev, task);
2871 for_each_task_context_nr(ctxn) {
2872 ctx = task->perf_event_ctxp[ctxn];
2876 perf_event_context_sched_in(ctx, task);
2879 if (atomic_read(&nr_switch_events))
2880 perf_event_switch(task, prev, true);
2882 if (__this_cpu_read(perf_sched_cb_usages))
2883 perf_pmu_sched_task(prev, task, true);
2886 static u64 perf_calculate_period(struct perf_event *event, u64 nsec, u64 count)
2888 u64 frequency = event->attr.sample_freq;
2889 u64 sec = NSEC_PER_SEC;
2890 u64 divisor, dividend;
2892 int count_fls, nsec_fls, frequency_fls, sec_fls;
2894 count_fls = fls64(count);
2895 nsec_fls = fls64(nsec);
2896 frequency_fls = fls64(frequency);
2900 * We got @count in @nsec, with a target of sample_freq HZ
2901 * the target period becomes:
2904 * period = -------------------
2905 * @nsec * sample_freq
2910 * Reduce accuracy by one bit such that @a and @b converge
2911 * to a similar magnitude.
2913 #define REDUCE_FLS(a, b) \
2915 if (a##_fls > b##_fls) { \
2925 * Reduce accuracy until either term fits in a u64, then proceed with
2926 * the other, so that finally we can do a u64/u64 division.
2928 while (count_fls + sec_fls > 64 && nsec_fls + frequency_fls > 64) {
2929 REDUCE_FLS(nsec, frequency);
2930 REDUCE_FLS(sec, count);
2933 if (count_fls + sec_fls > 64) {
2934 divisor = nsec * frequency;
2936 while (count_fls + sec_fls > 64) {
2937 REDUCE_FLS(count, sec);
2941 dividend = count * sec;
2943 dividend = count * sec;
2945 while (nsec_fls + frequency_fls > 64) {
2946 REDUCE_FLS(nsec, frequency);
2950 divisor = nsec * frequency;
2956 return div64_u64(dividend, divisor);
2959 static DEFINE_PER_CPU(int, perf_throttled_count);
2960 static DEFINE_PER_CPU(u64, perf_throttled_seq);
2962 static void perf_adjust_period(struct perf_event *event, u64 nsec, u64 count, bool disable)
2964 struct hw_perf_event *hwc = &event->hw;
2965 s64 period, sample_period;
2968 period = perf_calculate_period(event, nsec, count);
2970 delta = (s64)(period - hwc->sample_period);
2971 delta = (delta + 7) / 8; /* low pass filter */
2973 sample_period = hwc->sample_period + delta;
2978 hwc->sample_period = sample_period;
2980 if (local64_read(&hwc->period_left) > 8*sample_period) {
2982 event->pmu->stop(event, PERF_EF_UPDATE);
2984 local64_set(&hwc->period_left, 0);
2987 event->pmu->start(event, PERF_EF_RELOAD);
2992 * combine freq adjustment with unthrottling to avoid two passes over the
2993 * events. At the same time, make sure, having freq events does not change
2994 * the rate of unthrottling as that would introduce bias.
2996 static void perf_adjust_freq_unthr_context(struct perf_event_context *ctx,
2999 struct perf_event *event;
3000 struct hw_perf_event *hwc;
3001 u64 now, period = TICK_NSEC;
3005 * only need to iterate over all events iff:
3006 * - context have events in frequency mode (needs freq adjust)
3007 * - there are events to unthrottle on this cpu
3009 if (!(ctx->nr_freq || needs_unthr))
3012 raw_spin_lock(&ctx->lock);
3013 perf_pmu_disable(ctx->pmu);
3015 list_for_each_entry_rcu(event, &ctx->event_list, event_entry) {
3016 if (event->state != PERF_EVENT_STATE_ACTIVE)
3019 if (!event_filter_match(event))
3022 perf_pmu_disable(event->pmu);
3026 if (hwc->interrupts == MAX_INTERRUPTS) {
3027 hwc->interrupts = 0;
3028 perf_log_throttle(event, 1);
3029 event->pmu->start(event, 0);
3032 if (!event->attr.freq || !event->attr.sample_freq)
3036 * stop the event and update event->count
3038 event->pmu->stop(event, PERF_EF_UPDATE);
3040 now = local64_read(&event->count);
3041 delta = now - hwc->freq_count_stamp;
3042 hwc->freq_count_stamp = now;
3046 * reload only if value has changed
3047 * we have stopped the event so tell that
3048 * to perf_adjust_period() to avoid stopping it
3052 perf_adjust_period(event, period, delta, false);
3054 event->pmu->start(event, delta > 0 ? PERF_EF_RELOAD : 0);
3056 perf_pmu_enable(event->pmu);
3059 perf_pmu_enable(ctx->pmu);
3060 raw_spin_unlock(&ctx->lock);
3064 * Round-robin a context's events:
3066 static void rotate_ctx(struct perf_event_context *ctx)
3069 * Rotate the first entry last of non-pinned groups. Rotation might be
3070 * disabled by the inheritance code.
3072 if (!ctx->rotate_disable)
3073 list_rotate_left(&ctx->flexible_groups);
3076 static int perf_rotate_context(struct perf_cpu_context *cpuctx)
3078 struct perf_event_context *ctx = NULL;
3081 if (cpuctx->ctx.nr_events) {
3082 if (cpuctx->ctx.nr_events != cpuctx->ctx.nr_active)
3086 ctx = cpuctx->task_ctx;
3087 if (ctx && ctx->nr_events) {
3088 if (ctx->nr_events != ctx->nr_active)
3095 perf_ctx_lock(cpuctx, cpuctx->task_ctx);
3096 perf_pmu_disable(cpuctx->ctx.pmu);
3098 cpu_ctx_sched_out(cpuctx, EVENT_FLEXIBLE);
3100 ctx_sched_out(ctx, cpuctx, EVENT_FLEXIBLE);
3102 rotate_ctx(&cpuctx->ctx);
3106 perf_event_sched_in(cpuctx, ctx, current);
3108 perf_pmu_enable(cpuctx->ctx.pmu);
3109 perf_ctx_unlock(cpuctx, cpuctx->task_ctx);
3115 #ifdef CONFIG_NO_HZ_FULL
3116 bool perf_event_can_stop_tick(void)
3118 if (atomic_read(&nr_freq_events) ||
3119 __this_cpu_read(perf_throttled_count))
3126 void perf_event_task_tick(void)
3128 struct list_head *head = this_cpu_ptr(&active_ctx_list);
3129 struct perf_event_context *ctx, *tmp;
3132 WARN_ON(!irqs_disabled());
3134 __this_cpu_inc(perf_throttled_seq);
3135 throttled = __this_cpu_xchg(perf_throttled_count, 0);
3137 list_for_each_entry_safe(ctx, tmp, head, active_ctx_list)
3138 perf_adjust_freq_unthr_context(ctx, throttled);
3141 static int event_enable_on_exec(struct perf_event *event,
3142 struct perf_event_context *ctx)
3144 if (!event->attr.enable_on_exec)
3147 event->attr.enable_on_exec = 0;
3148 if (event->state >= PERF_EVENT_STATE_INACTIVE)
3151 __perf_event_mark_enabled(event);
3157 * Enable all of a task's events that have been marked enable-on-exec.
3158 * This expects task == current.
3160 static void perf_event_enable_on_exec(int ctxn)
3162 struct perf_event_context *ctx, *clone_ctx = NULL;
3163 struct perf_cpu_context *cpuctx;
3164 struct perf_event *event;
3165 unsigned long flags;
3168 local_irq_save(flags);
3169 ctx = current->perf_event_ctxp[ctxn];
3170 if (!ctx || !ctx->nr_events)
3173 cpuctx = __get_cpu_context(ctx);
3174 perf_ctx_lock(cpuctx, ctx);
3175 ctx_sched_out(ctx, cpuctx, EVENT_TIME);
3176 list_for_each_entry(event, &ctx->event_list, event_entry)
3177 enabled |= event_enable_on_exec(event, ctx);
3180 * Unclone and reschedule this context if we enabled any event.
3183 clone_ctx = unclone_ctx(ctx);
3184 ctx_resched(cpuctx, ctx);
3186 perf_ctx_unlock(cpuctx, ctx);
3189 local_irq_restore(flags);
3195 void perf_event_exec(void)
3200 for_each_task_context_nr(ctxn)
3201 perf_event_enable_on_exec(ctxn);
3205 struct perf_read_data {
3206 struct perf_event *event;
3212 * Cross CPU call to read the hardware event
3214 static void __perf_event_read(void *info)
3216 struct perf_read_data *data = info;
3217 struct perf_event *sub, *event = data->event;
3218 struct perf_event_context *ctx = event->ctx;
3219 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
3220 struct pmu *pmu = event->pmu;
3223 * If this is a task context, we need to check whether it is
3224 * the current task context of this cpu. If not it has been
3225 * scheduled out before the smp call arrived. In that case
3226 * event->count would have been updated to a recent sample
3227 * when the event was scheduled out.
3229 if (ctx->task && cpuctx->task_ctx != ctx)
3232 raw_spin_lock(&ctx->lock);
3233 if (ctx->is_active) {
3234 update_context_time(ctx);
3235 update_cgrp_time_from_event(event);
3238 update_event_times(event);
3239 if (event->state != PERF_EVENT_STATE_ACTIVE)
3248 pmu->start_txn(pmu, PERF_PMU_TXN_READ);
3252 list_for_each_entry(sub, &event->sibling_list, group_entry) {
3253 update_event_times(sub);
3254 if (sub->state == PERF_EVENT_STATE_ACTIVE) {
3256 * Use sibling's PMU rather than @event's since
3257 * sibling could be on different (eg: software) PMU.
3259 sub->pmu->read(sub);
3263 data->ret = pmu->commit_txn(pmu);
3266 raw_spin_unlock(&ctx->lock);
3269 static inline u64 perf_event_count(struct perf_event *event)
3271 if (event->pmu->count)
3272 return event->pmu->count(event);
3274 return __perf_event_count(event);
3278 * NMI-safe method to read a local event, that is an event that
3280 * - either for the current task, or for this CPU
3281 * - does not have inherit set, for inherited task events
3282 * will not be local and we cannot read them atomically
3283 * - must not have a pmu::count method
3285 u64 perf_event_read_local(struct perf_event *event)
3287 unsigned long flags;
3291 * Disabling interrupts avoids all counter scheduling (context
3292 * switches, timer based rotation and IPIs).
3294 local_irq_save(flags);
3296 /* If this is a per-task event, it must be for current */
3297 WARN_ON_ONCE((event->attach_state & PERF_ATTACH_TASK) &&
3298 event->hw.target != current);
3300 /* If this is a per-CPU event, it must be for this CPU */
3301 WARN_ON_ONCE(!(event->attach_state & PERF_ATTACH_TASK) &&
3302 event->cpu != smp_processor_id());
3305 * It must not be an event with inherit set, we cannot read
3306 * all child counters from atomic context.
3308 WARN_ON_ONCE(event->attr.inherit);
3311 * It must not have a pmu::count method, those are not
3314 WARN_ON_ONCE(event->pmu->count);
3317 * If the event is currently on this CPU, its either a per-task event,
3318 * or local to this CPU. Furthermore it means its ACTIVE (otherwise
3321 if (event->oncpu == smp_processor_id())
3322 event->pmu->read(event);
3324 val = local64_read(&event->count);
3325 local_irq_restore(flags);
3330 static int perf_event_read(struct perf_event *event, bool group)
3335 * If event is enabled and currently active on a CPU, update the
3336 * value in the event structure:
3338 if (event->state == PERF_EVENT_STATE_ACTIVE) {
3339 struct perf_read_data data = {
3344 smp_call_function_single(event->oncpu,
3345 __perf_event_read, &data, 1);
3347 } else if (event->state == PERF_EVENT_STATE_INACTIVE) {
3348 struct perf_event_context *ctx = event->ctx;
3349 unsigned long flags;
3351 raw_spin_lock_irqsave(&ctx->lock, flags);
3353 * may read while context is not active
3354 * (e.g., thread is blocked), in that case
3355 * we cannot update context time
3357 if (ctx->is_active) {
3358 update_context_time(ctx);
3359 update_cgrp_time_from_event(event);
3362 update_group_times(event);
3364 update_event_times(event);
3365 raw_spin_unlock_irqrestore(&ctx->lock, flags);
3372 * Initialize the perf_event context in a task_struct:
3374 static void __perf_event_init_context(struct perf_event_context *ctx)
3376 raw_spin_lock_init(&ctx->lock);
3377 mutex_init(&ctx->mutex);
3378 INIT_LIST_HEAD(&ctx->active_ctx_list);
3379 INIT_LIST_HEAD(&ctx->pinned_groups);
3380 INIT_LIST_HEAD(&ctx->flexible_groups);
3381 INIT_LIST_HEAD(&ctx->event_list);
3382 atomic_set(&ctx->refcount, 1);
3385 static struct perf_event_context *
3386 alloc_perf_context(struct pmu *pmu, struct task_struct *task)
3388 struct perf_event_context *ctx;
3390 ctx = kzalloc(sizeof(struct perf_event_context), GFP_KERNEL);
3394 __perf_event_init_context(ctx);
3397 get_task_struct(task);
3404 static struct task_struct *
3405 find_lively_task_by_vpid(pid_t vpid)
3407 struct task_struct *task;
3414 task = find_task_by_vpid(vpid);
3416 get_task_struct(task);
3420 return ERR_PTR(-ESRCH);
3422 /* Reuse ptrace permission checks for now. */
3424 if (!ptrace_may_access(task, PTRACE_MODE_READ_REALCREDS))
3429 put_task_struct(task);
3430 return ERR_PTR(err);
3435 * Returns a matching context with refcount and pincount.
3437 static struct perf_event_context *
3438 find_get_context(struct pmu *pmu, struct task_struct *task,
3439 struct perf_event *event)
3441 struct perf_event_context *ctx, *clone_ctx = NULL;
3442 struct perf_cpu_context *cpuctx;
3443 void *task_ctx_data = NULL;
3444 unsigned long flags;
3446 int cpu = event->cpu;
3449 /* Must be root to operate on a CPU event: */
3450 if (perf_paranoid_cpu() && !capable(CAP_SYS_ADMIN))
3451 return ERR_PTR(-EACCES);
3454 * We could be clever and allow to attach a event to an
3455 * offline CPU and activate it when the CPU comes up, but
3458 if (!cpu_online(cpu))
3459 return ERR_PTR(-ENODEV);
3461 cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
3470 ctxn = pmu->task_ctx_nr;
3474 if (event->attach_state & PERF_ATTACH_TASK_DATA) {
3475 task_ctx_data = kzalloc(pmu->task_ctx_size, GFP_KERNEL);
3476 if (!task_ctx_data) {
3483 ctx = perf_lock_task_context(task, ctxn, &flags);
3485 clone_ctx = unclone_ctx(ctx);
3488 if (task_ctx_data && !ctx->task_ctx_data) {
3489 ctx->task_ctx_data = task_ctx_data;
3490 task_ctx_data = NULL;
3492 raw_spin_unlock_irqrestore(&ctx->lock, flags);
3497 ctx = alloc_perf_context(pmu, task);
3502 if (task_ctx_data) {
3503 ctx->task_ctx_data = task_ctx_data;
3504 task_ctx_data = NULL;
3508 mutex_lock(&task->perf_event_mutex);
3510 * If it has already passed perf_event_exit_task().
3511 * we must see PF_EXITING, it takes this mutex too.
3513 if (task->flags & PF_EXITING)
3515 else if (task->perf_event_ctxp[ctxn])
3520 rcu_assign_pointer(task->perf_event_ctxp[ctxn], ctx);
3522 mutex_unlock(&task->perf_event_mutex);
3524 if (unlikely(err)) {
3533 kfree(task_ctx_data);
3537 kfree(task_ctx_data);
3538 return ERR_PTR(err);
3541 static void perf_event_free_filter(struct perf_event *event);
3542 static void perf_event_free_bpf_prog(struct perf_event *event);
3544 static void free_event_rcu(struct rcu_head *head)
3546 struct perf_event *event;
3548 event = container_of(head, struct perf_event, rcu_head);
3550 put_pid_ns(event->ns);
3551 perf_event_free_filter(event);
3555 static void ring_buffer_attach(struct perf_event *event,
3556 struct ring_buffer *rb);
3558 static void unaccount_event_cpu(struct perf_event *event, int cpu)
3563 if (is_cgroup_event(event))
3564 atomic_dec(&per_cpu(perf_cgroup_events, cpu));
3567 static void unaccount_event(struct perf_event *event)
3574 if (event->attach_state & PERF_ATTACH_TASK)
3576 if (event->attr.mmap || event->attr.mmap_data)
3577 atomic_dec(&nr_mmap_events);
3578 if (event->attr.comm)
3579 atomic_dec(&nr_comm_events);
3580 if (event->attr.task)
3581 atomic_dec(&nr_task_events);
3582 if (event->attr.freq)
3583 atomic_dec(&nr_freq_events);
3584 if (event->attr.context_switch) {
3586 atomic_dec(&nr_switch_events);
3588 if (is_cgroup_event(event))
3590 if (has_branch_stack(event))
3594 if (!atomic_add_unless(&perf_sched_count, -1, 1))
3595 schedule_delayed_work(&perf_sched_work, HZ);
3598 unaccount_event_cpu(event, event->cpu);
3601 static void perf_sched_delayed(struct work_struct *work)
3603 mutex_lock(&perf_sched_mutex);
3604 if (atomic_dec_and_test(&perf_sched_count))
3605 static_branch_disable(&perf_sched_events);
3606 mutex_unlock(&perf_sched_mutex);
3610 * The following implement mutual exclusion of events on "exclusive" pmus
3611 * (PERF_PMU_CAP_EXCLUSIVE). Such pmus can only have one event scheduled
3612 * at a time, so we disallow creating events that might conflict, namely:
3614 * 1) cpu-wide events in the presence of per-task events,
3615 * 2) per-task events in the presence of cpu-wide events,
3616 * 3) two matching events on the same context.
3618 * The former two cases are handled in the allocation path (perf_event_alloc(),
3619 * _free_event()), the latter -- before the first perf_install_in_context().
3621 static int exclusive_event_init(struct perf_event *event)
3623 struct pmu *pmu = event->pmu;
3625 if (!(pmu->capabilities & PERF_PMU_CAP_EXCLUSIVE))
3629 * Prevent co-existence of per-task and cpu-wide events on the
3630 * same exclusive pmu.
3632 * Negative pmu::exclusive_cnt means there are cpu-wide
3633 * events on this "exclusive" pmu, positive means there are
3636 * Since this is called in perf_event_alloc() path, event::ctx
3637 * doesn't exist yet; it is, however, safe to use PERF_ATTACH_TASK
3638 * to mean "per-task event", because unlike other attach states it
3639 * never gets cleared.
3641 if (event->attach_state & PERF_ATTACH_TASK) {
3642 if (!atomic_inc_unless_negative(&pmu->exclusive_cnt))
3645 if (!atomic_dec_unless_positive(&pmu->exclusive_cnt))
3652 static void exclusive_event_destroy(struct perf_event *event)
3654 struct pmu *pmu = event->pmu;
3656 if (!(pmu->capabilities & PERF_PMU_CAP_EXCLUSIVE))
3659 /* see comment in exclusive_event_init() */
3660 if (event->attach_state & PERF_ATTACH_TASK)
3661 atomic_dec(&pmu->exclusive_cnt);
3663 atomic_inc(&pmu->exclusive_cnt);
3666 static bool exclusive_event_match(struct perf_event *e1, struct perf_event *e2)
3668 if ((e1->pmu->capabilities & PERF_PMU_CAP_EXCLUSIVE) &&
3669 (e1->cpu == e2->cpu ||
3676 /* Called under the same ctx::mutex as perf_install_in_context() */
3677 static bool exclusive_event_installable(struct perf_event *event,
3678 struct perf_event_context *ctx)
3680 struct perf_event *iter_event;
3681 struct pmu *pmu = event->pmu;
3683 if (!(pmu->capabilities & PERF_PMU_CAP_EXCLUSIVE))
3686 list_for_each_entry(iter_event, &ctx->event_list, event_entry) {
3687 if (exclusive_event_match(iter_event, event))
3694 static void _free_event(struct perf_event *event)
3696 irq_work_sync(&event->pending);
3698 unaccount_event(event);
3702 * Can happen when we close an event with re-directed output.
3704 * Since we have a 0 refcount, perf_mmap_close() will skip
3705 * over us; possibly making our ring_buffer_put() the last.
3707 mutex_lock(&event->mmap_mutex);
3708 ring_buffer_attach(event, NULL);
3709 mutex_unlock(&event->mmap_mutex);
3712 if (is_cgroup_event(event))
3713 perf_detach_cgroup(event);
3715 if (!event->parent) {
3716 if (event->attr.sample_type & PERF_SAMPLE_CALLCHAIN)
3717 put_callchain_buffers();
3720 perf_event_free_bpf_prog(event);
3723 event->destroy(event);
3726 put_ctx(event->ctx);
3729 exclusive_event_destroy(event);
3730 module_put(event->pmu->module);
3733 call_rcu(&event->rcu_head, free_event_rcu);
3737 * Used to free events which have a known refcount of 1, such as in error paths
3738 * where the event isn't exposed yet and inherited events.
3740 static void free_event(struct perf_event *event)
3742 if (WARN(atomic_long_cmpxchg(&event->refcount, 1, 0) != 1,
3743 "unexpected event refcount: %ld; ptr=%p\n",
3744 atomic_long_read(&event->refcount), event)) {
3745 /* leak to avoid use-after-free */
3753 * Remove user event from the owner task.
3755 static void perf_remove_from_owner(struct perf_event *event)
3757 struct task_struct *owner;
3761 * Matches the smp_store_release() in perf_event_exit_task(). If we
3762 * observe !owner it means the list deletion is complete and we can
3763 * indeed free this event, otherwise we need to serialize on
3764 * owner->perf_event_mutex.
3766 owner = lockless_dereference(event->owner);
3769 * Since delayed_put_task_struct() also drops the last
3770 * task reference we can safely take a new reference
3771 * while holding the rcu_read_lock().
3773 get_task_struct(owner);
3779 * If we're here through perf_event_exit_task() we're already
3780 * holding ctx->mutex which would be an inversion wrt. the
3781 * normal lock order.
3783 * However we can safely take this lock because its the child
3786 mutex_lock_nested(&owner->perf_event_mutex, SINGLE_DEPTH_NESTING);
3789 * We have to re-check the event->owner field, if it is cleared
3790 * we raced with perf_event_exit_task(), acquiring the mutex
3791 * ensured they're done, and we can proceed with freeing the
3795 list_del_init(&event->owner_entry);
3796 smp_store_release(&event->owner, NULL);
3798 mutex_unlock(&owner->perf_event_mutex);
3799 put_task_struct(owner);
3803 static void put_event(struct perf_event *event)
3805 if (!atomic_long_dec_and_test(&event->refcount))
3812 * Kill an event dead; while event:refcount will preserve the event
3813 * object, it will not preserve its functionality. Once the last 'user'
3814 * gives up the object, we'll destroy the thing.
3816 int perf_event_release_kernel(struct perf_event *event)
3818 struct perf_event_context *ctx = event->ctx;
3819 struct perf_event *child, *tmp;
3822 * If we got here through err_file: fput(event_file); we will not have
3823 * attached to a context yet.
3826 WARN_ON_ONCE(event->attach_state &
3827 (PERF_ATTACH_CONTEXT|PERF_ATTACH_GROUP));
3831 if (!is_kernel_event(event))
3832 perf_remove_from_owner(event);
3834 ctx = perf_event_ctx_lock(event);
3835 WARN_ON_ONCE(ctx->parent_ctx);
3836 perf_remove_from_context(event, DETACH_GROUP);
3838 raw_spin_lock_irq(&ctx->lock);
3840 * Mark this even as STATE_DEAD, there is no external reference to it
3843 * Anybody acquiring event->child_mutex after the below loop _must_
3844 * also see this, most importantly inherit_event() which will avoid
3845 * placing more children on the list.
3847 * Thus this guarantees that we will in fact observe and kill _ALL_
3850 event->state = PERF_EVENT_STATE_DEAD;
3851 raw_spin_unlock_irq(&ctx->lock);
3853 perf_event_ctx_unlock(event, ctx);
3856 mutex_lock(&event->child_mutex);
3857 list_for_each_entry(child, &event->child_list, child_list) {
3860 * Cannot change, child events are not migrated, see the
3861 * comment with perf_event_ctx_lock_nested().
3863 ctx = lockless_dereference(child->ctx);
3865 * Since child_mutex nests inside ctx::mutex, we must jump
3866 * through hoops. We start by grabbing a reference on the ctx.
3868 * Since the event cannot get freed while we hold the
3869 * child_mutex, the context must also exist and have a !0
3875 * Now that we have a ctx ref, we can drop child_mutex, and
3876 * acquire ctx::mutex without fear of it going away. Then we
3877 * can re-acquire child_mutex.
3879 mutex_unlock(&event->child_mutex);
3880 mutex_lock(&ctx->mutex);
3881 mutex_lock(&event->child_mutex);
3884 * Now that we hold ctx::mutex and child_mutex, revalidate our
3885 * state, if child is still the first entry, it didn't get freed
3886 * and we can continue doing so.
3888 tmp = list_first_entry_or_null(&event->child_list,
3889 struct perf_event, child_list);
3891 perf_remove_from_context(child, DETACH_GROUP);
3892 list_del(&child->child_list);
3895 * This matches the refcount bump in inherit_event();
3896 * this can't be the last reference.
3901 mutex_unlock(&event->child_mutex);
3902 mutex_unlock(&ctx->mutex);
3906 mutex_unlock(&event->child_mutex);
3909 put_event(event); /* Must be the 'last' reference */
3912 EXPORT_SYMBOL_GPL(perf_event_release_kernel);
3915 * Called when the last reference to the file is gone.
3917 static int perf_release(struct inode *inode, struct file *file)
3919 perf_event_release_kernel(file->private_data);
3923 u64 perf_event_read_value(struct perf_event *event, u64 *enabled, u64 *running)
3925 struct perf_event *child;
3931 mutex_lock(&event->child_mutex);
3933 (void)perf_event_read(event, false);
3934 total += perf_event_count(event);
3936 *enabled += event->total_time_enabled +
3937 atomic64_read(&event->child_total_time_enabled);
3938 *running += event->total_time_running +
3939 atomic64_read(&event->child_total_time_running);
3941 list_for_each_entry(child, &event->child_list, child_list) {
3942 (void)perf_event_read(child, false);
3943 total += perf_event_count(child);
3944 *enabled += child->total_time_enabled;
3945 *running += child->total_time_running;
3947 mutex_unlock(&event->child_mutex);
3951 EXPORT_SYMBOL_GPL(perf_event_read_value);
3953 static int __perf_read_group_add(struct perf_event *leader,
3954 u64 read_format, u64 *values)
3956 struct perf_event *sub;
3957 int n = 1; /* skip @nr */
3960 ret = perf_event_read(leader, true);
3965 * Since we co-schedule groups, {enabled,running} times of siblings
3966 * will be identical to those of the leader, so we only publish one
3969 if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED) {
3970 values[n++] += leader->total_time_enabled +
3971 atomic64_read(&leader->child_total_time_enabled);
3974 if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING) {
3975 values[n++] += leader->total_time_running +
3976 atomic64_read(&leader->child_total_time_running);
3980 * Write {count,id} tuples for every sibling.
3982 values[n++] += perf_event_count(leader);
3983 if (read_format & PERF_FORMAT_ID)
3984 values[n++] = primary_event_id(leader);
3986 list_for_each_entry(sub, &leader->sibling_list, group_entry) {
3987 values[n++] += perf_event_count(sub);
3988 if (read_format & PERF_FORMAT_ID)
3989 values[n++] = primary_event_id(sub);
3995 static int perf_read_group(struct perf_event *event,
3996 u64 read_format, char __user *buf)
3998 struct perf_event *leader = event->group_leader, *child;
3999 struct perf_event_context *ctx = leader->ctx;
4003 lockdep_assert_held(&ctx->mutex);
4005 values = kzalloc(event->read_size, GFP_KERNEL);
4009 values[0] = 1 + leader->nr_siblings;
4012 * By locking the child_mutex of the leader we effectively
4013 * lock the child list of all siblings.. XXX explain how.
4015 mutex_lock(&leader->child_mutex);
4017 ret = __perf_read_group_add(leader, read_format, values);
4021 list_for_each_entry(child, &leader->child_list, child_list) {
4022 ret = __perf_read_group_add(child, read_format, values);
4027 mutex_unlock(&leader->child_mutex);
4029 ret = event->read_size;
4030 if (copy_to_user(buf, values, event->read_size))
4035 mutex_unlock(&leader->child_mutex);
4041 static int perf_read_one(struct perf_event *event,
4042 u64 read_format, char __user *buf)
4044 u64 enabled, running;
4048 values[n++] = perf_event_read_value(event, &enabled, &running);
4049 if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED)
4050 values[n++] = enabled;
4051 if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING)
4052 values[n++] = running;
4053 if (read_format & PERF_FORMAT_ID)
4054 values[n++] = primary_event_id(event);
4056 if (copy_to_user(buf, values, n * sizeof(u64)))
4059 return n * sizeof(u64);
4062 static bool is_event_hup(struct perf_event *event)
4066 if (event->state > PERF_EVENT_STATE_EXIT)
4069 mutex_lock(&event->child_mutex);
4070 no_children = list_empty(&event->child_list);
4071 mutex_unlock(&event->child_mutex);
4076 * Read the performance event - simple non blocking version for now
4079 __perf_read(struct perf_event *event, char __user *buf, size_t count)
4081 u64 read_format = event->attr.read_format;
4085 * Return end-of-file for a read on a event that is in
4086 * error state (i.e. because it was pinned but it couldn't be
4087 * scheduled on to the CPU at some point).
4089 if (event->state == PERF_EVENT_STATE_ERROR)
4092 if (count < event->read_size)
4095 WARN_ON_ONCE(event->ctx->parent_ctx);
4096 if (read_format & PERF_FORMAT_GROUP)
4097 ret = perf_read_group(event, read_format, buf);
4099 ret = perf_read_one(event, read_format, buf);
4105 perf_read(struct file *file, char __user *buf, size_t count, loff_t *ppos)
4107 struct perf_event *event = file->private_data;
4108 struct perf_event_context *ctx;
4111 ctx = perf_event_ctx_lock(event);
4112 ret = __perf_read(event, buf, count);
4113 perf_event_ctx_unlock(event, ctx);
4118 static unsigned int perf_poll(struct file *file, poll_table *wait)
4120 struct perf_event *event = file->private_data;
4121 struct ring_buffer *rb;
4122 unsigned int events = POLLHUP;
4124 poll_wait(file, &event->waitq, wait);
4126 if (is_event_hup(event))
4130 * Pin the event->rb by taking event->mmap_mutex; otherwise
4131 * perf_event_set_output() can swizzle our rb and make us miss wakeups.
4133 mutex_lock(&event->mmap_mutex);
4136 events = atomic_xchg(&rb->poll, 0);
4137 mutex_unlock(&event->mmap_mutex);
4141 static void _perf_event_reset(struct perf_event *event)
4143 (void)perf_event_read(event, false);
4144 local64_set(&event->count, 0);
4145 perf_event_update_userpage(event);
4149 * Holding the top-level event's child_mutex means that any
4150 * descendant process that has inherited this event will block
4151 * in perf_event_exit_event() if it goes to exit, thus satisfying the
4152 * task existence requirements of perf_event_enable/disable.
4154 static void perf_event_for_each_child(struct perf_event *event,
4155 void (*func)(struct perf_event *))
4157 struct perf_event *child;
4159 WARN_ON_ONCE(event->ctx->parent_ctx);
4161 mutex_lock(&event->child_mutex);
4163 list_for_each_entry(child, &event->child_list, child_list)
4165 mutex_unlock(&event->child_mutex);
4168 static void perf_event_for_each(struct perf_event *event,
4169 void (*func)(struct perf_event *))
4171 struct perf_event_context *ctx = event->ctx;
4172 struct perf_event *sibling;
4174 lockdep_assert_held(&ctx->mutex);
4176 event = event->group_leader;
4178 perf_event_for_each_child(event, func);
4179 list_for_each_entry(sibling, &event->sibling_list, group_entry)
4180 perf_event_for_each_child(sibling, func);
4183 static void __perf_event_period(struct perf_event *event,
4184 struct perf_cpu_context *cpuctx,
4185 struct perf_event_context *ctx,
4188 u64 value = *((u64 *)info);
4191 if (event->attr.freq) {
4192 event->attr.sample_freq = value;
4194 event->attr.sample_period = value;
4195 event->hw.sample_period = value;
4198 active = (event->state == PERF_EVENT_STATE_ACTIVE);
4200 perf_pmu_disable(ctx->pmu);
4201 event->pmu->stop(event, PERF_EF_UPDATE);
4204 local64_set(&event->hw.period_left, 0);
4207 event->pmu->start(event, PERF_EF_RELOAD);
4208 perf_pmu_enable(ctx->pmu);
4212 static int perf_event_period(struct perf_event *event, u64 __user *arg)
4216 if (!is_sampling_event(event))
4219 if (copy_from_user(&value, arg, sizeof(value)))
4225 if (event->attr.freq && value > sysctl_perf_event_sample_rate)
4228 event_function_call(event, __perf_event_period, &value);
4233 static const struct file_operations perf_fops;
4235 static inline int perf_fget_light(int fd, struct fd *p)
4237 struct fd f = fdget(fd);
4241 if (f.file->f_op != &perf_fops) {
4249 static int perf_event_set_output(struct perf_event *event,
4250 struct perf_event *output_event);
4251 static int perf_event_set_filter(struct perf_event *event, void __user *arg);
4252 static int perf_event_set_bpf_prog(struct perf_event *event, u32 prog_fd);
4254 static long _perf_ioctl(struct perf_event *event, unsigned int cmd, unsigned long arg)
4256 void (*func)(struct perf_event *);
4260 case PERF_EVENT_IOC_ENABLE:
4261 func = _perf_event_enable;
4263 case PERF_EVENT_IOC_DISABLE:
4264 func = _perf_event_disable;
4266 case PERF_EVENT_IOC_RESET:
4267 func = _perf_event_reset;
4270 case PERF_EVENT_IOC_REFRESH:
4271 return _perf_event_refresh(event, arg);
4273 case PERF_EVENT_IOC_PERIOD:
4274 return perf_event_period(event, (u64 __user *)arg);
4276 case PERF_EVENT_IOC_ID:
4278 u64 id = primary_event_id(event);
4280 if (copy_to_user((void __user *)arg, &id, sizeof(id)))
4285 case PERF_EVENT_IOC_SET_OUTPUT:
4289 struct perf_event *output_event;
4291 ret = perf_fget_light(arg, &output);
4294 output_event = output.file->private_data;
4295 ret = perf_event_set_output(event, output_event);
4298 ret = perf_event_set_output(event, NULL);
4303 case PERF_EVENT_IOC_SET_FILTER:
4304 return perf_event_set_filter(event, (void __user *)arg);
4306 case PERF_EVENT_IOC_SET_BPF:
4307 return perf_event_set_bpf_prog(event, arg);
4313 if (flags & PERF_IOC_FLAG_GROUP)
4314 perf_event_for_each(event, func);
4316 perf_event_for_each_child(event, func);
4321 static long perf_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
4323 struct perf_event *event = file->private_data;
4324 struct perf_event_context *ctx;
4327 ctx = perf_event_ctx_lock(event);
4328 ret = _perf_ioctl(event, cmd, arg);
4329 perf_event_ctx_unlock(event, ctx);
4334 #ifdef CONFIG_COMPAT
4335 static long perf_compat_ioctl(struct file *file, unsigned int cmd,
4338 switch (_IOC_NR(cmd)) {
4339 case _IOC_NR(PERF_EVENT_IOC_SET_FILTER):
4340 case _IOC_NR(PERF_EVENT_IOC_ID):
4341 /* Fix up pointer size (usually 4 -> 8 in 32-on-64-bit case */
4342 if (_IOC_SIZE(cmd) == sizeof(compat_uptr_t)) {
4343 cmd &= ~IOCSIZE_MASK;
4344 cmd |= sizeof(void *) << IOCSIZE_SHIFT;
4348 return perf_ioctl(file, cmd, arg);
4351 # define perf_compat_ioctl NULL
4354 int perf_event_task_enable(void)
4356 struct perf_event_context *ctx;
4357 struct perf_event *event;
4359 mutex_lock(¤t->perf_event_mutex);
4360 list_for_each_entry(event, ¤t->perf_event_list, owner_entry) {
4361 ctx = perf_event_ctx_lock(event);
4362 perf_event_for_each_child(event, _perf_event_enable);
4363 perf_event_ctx_unlock(event, ctx);
4365 mutex_unlock(¤t->perf_event_mutex);
4370 int perf_event_task_disable(void)
4372 struct perf_event_context *ctx;
4373 struct perf_event *event;
4375 mutex_lock(¤t->perf_event_mutex);
4376 list_for_each_entry(event, ¤t->perf_event_list, owner_entry) {
4377 ctx = perf_event_ctx_lock(event);
4378 perf_event_for_each_child(event, _perf_event_disable);
4379 perf_event_ctx_unlock(event, ctx);
4381 mutex_unlock(¤t->perf_event_mutex);
4386 static int perf_event_index(struct perf_event *event)
4388 if (event->hw.state & PERF_HES_STOPPED)
4391 if (event->state != PERF_EVENT_STATE_ACTIVE)
4394 return event->pmu->event_idx(event);
4397 static void calc_timer_values(struct perf_event *event,
4404 *now = perf_clock();
4405 ctx_time = event->shadow_ctx_time + *now;
4406 *enabled = ctx_time - event->tstamp_enabled;
4407 *running = ctx_time - event->tstamp_running;
4410 static void perf_event_init_userpage(struct perf_event *event)
4412 struct perf_event_mmap_page *userpg;
4413 struct ring_buffer *rb;
4416 rb = rcu_dereference(event->rb);
4420 userpg = rb->user_page;
4422 /* Allow new userspace to detect that bit 0 is deprecated */
4423 userpg->cap_bit0_is_deprecated = 1;
4424 userpg->size = offsetof(struct perf_event_mmap_page, __reserved);
4425 userpg->data_offset = PAGE_SIZE;
4426 userpg->data_size = perf_data_size(rb);
4432 void __weak arch_perf_update_userpage(
4433 struct perf_event *event, struct perf_event_mmap_page *userpg, u64 now)
4438 * Callers need to ensure there can be no nesting of this function, otherwise
4439 * the seqlock logic goes bad. We can not serialize this because the arch
4440 * code calls this from NMI context.
4442 void perf_event_update_userpage(struct perf_event *event)
4444 struct perf_event_mmap_page *userpg;
4445 struct ring_buffer *rb;
4446 u64 enabled, running, now;
4449 rb = rcu_dereference(event->rb);
4454 * compute total_time_enabled, total_time_running
4455 * based on snapshot values taken when the event
4456 * was last scheduled in.
4458 * we cannot simply called update_context_time()
4459 * because of locking issue as we can be called in
4462 calc_timer_values(event, &now, &enabled, &running);
4464 userpg = rb->user_page;
4466 * Disable preemption so as to not let the corresponding user-space
4467 * spin too long if we get preempted.
4472 userpg->index = perf_event_index(event);
4473 userpg->offset = perf_event_count(event);
4475 userpg->offset -= local64_read(&event->hw.prev_count);
4477 userpg->time_enabled = enabled +
4478 atomic64_read(&event->child_total_time_enabled);
4480 userpg->time_running = running +
4481 atomic64_read(&event->child_total_time_running);
4483 arch_perf_update_userpage(event, userpg, now);
4492 static int perf_mmap_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
4494 struct perf_event *event = vma->vm_file->private_data;
4495 struct ring_buffer *rb;
4496 int ret = VM_FAULT_SIGBUS;
4498 if (vmf->flags & FAULT_FLAG_MKWRITE) {
4499 if (vmf->pgoff == 0)
4505 rb = rcu_dereference(event->rb);
4509 if (vmf->pgoff && (vmf->flags & FAULT_FLAG_WRITE))
4512 vmf->page = perf_mmap_to_page(rb, vmf->pgoff);
4516 get_page(vmf->page);
4517 vmf->page->mapping = vma->vm_file->f_mapping;
4518 vmf->page->index = vmf->pgoff;
4527 static void ring_buffer_attach(struct perf_event *event,
4528 struct ring_buffer *rb)
4530 struct ring_buffer *old_rb = NULL;
4531 unsigned long flags;
4535 * Should be impossible, we set this when removing
4536 * event->rb_entry and wait/clear when adding event->rb_entry.
4538 WARN_ON_ONCE(event->rcu_pending);
4541 spin_lock_irqsave(&old_rb->event_lock, flags);
4542 list_del_rcu(&event->rb_entry);
4543 spin_unlock_irqrestore(&old_rb->event_lock, flags);
4545 event->rcu_batches = get_state_synchronize_rcu();
4546 event->rcu_pending = 1;
4550 if (event->rcu_pending) {
4551 cond_synchronize_rcu(event->rcu_batches);
4552 event->rcu_pending = 0;
4555 spin_lock_irqsave(&rb->event_lock, flags);
4556 list_add_rcu(&event->rb_entry, &rb->event_list);
4557 spin_unlock_irqrestore(&rb->event_lock, flags);
4560 rcu_assign_pointer(event->rb, rb);
4563 ring_buffer_put(old_rb);
4565 * Since we detached before setting the new rb, so that we
4566 * could attach the new rb, we could have missed a wakeup.
4569 wake_up_all(&event->waitq);
4573 static void ring_buffer_wakeup(struct perf_event *event)
4575 struct ring_buffer *rb;
4578 rb = rcu_dereference(event->rb);
4580 list_for_each_entry_rcu(event, &rb->event_list, rb_entry)
4581 wake_up_all(&event->waitq);
4586 struct ring_buffer *ring_buffer_get(struct perf_event *event)
4588 struct ring_buffer *rb;
4591 rb = rcu_dereference(event->rb);
4593 if (!atomic_inc_not_zero(&rb->refcount))
4601 void ring_buffer_put(struct ring_buffer *rb)
4603 if (!atomic_dec_and_test(&rb->refcount))
4606 WARN_ON_ONCE(!list_empty(&rb->event_list));
4608 call_rcu(&rb->rcu_head, rb_free_rcu);
4611 static void perf_mmap_open(struct vm_area_struct *vma)
4613 struct perf_event *event = vma->vm_file->private_data;
4615 atomic_inc(&event->mmap_count);
4616 atomic_inc(&event->rb->mmap_count);
4619 atomic_inc(&event->rb->aux_mmap_count);
4621 if (event->pmu->event_mapped)
4622 event->pmu->event_mapped(event);
4626 * A buffer can be mmap()ed multiple times; either directly through the same
4627 * event, or through other events by use of perf_event_set_output().
4629 * In order to undo the VM accounting done by perf_mmap() we need to destroy
4630 * the buffer here, where we still have a VM context. This means we need
4631 * to detach all events redirecting to us.
4633 static void perf_mmap_close(struct vm_area_struct *vma)
4635 struct perf_event *event = vma->vm_file->private_data;
4637 struct ring_buffer *rb = ring_buffer_get(event);
4638 struct user_struct *mmap_user = rb->mmap_user;
4639 int mmap_locked = rb->mmap_locked;
4640 unsigned long size = perf_data_size(rb);
4642 if (event->pmu->event_unmapped)
4643 event->pmu->event_unmapped(event);
4646 * rb->aux_mmap_count will always drop before rb->mmap_count and
4647 * event->mmap_count, so it is ok to use event->mmap_mutex to
4648 * serialize with perf_mmap here.
4650 if (rb_has_aux(rb) && vma->vm_pgoff == rb->aux_pgoff &&
4651 atomic_dec_and_mutex_lock(&rb->aux_mmap_count, &event->mmap_mutex)) {
4652 atomic_long_sub(rb->aux_nr_pages, &mmap_user->locked_vm);
4653 vma->vm_mm->pinned_vm -= rb->aux_mmap_locked;
4656 mutex_unlock(&event->mmap_mutex);
4659 atomic_dec(&rb->mmap_count);
4661 if (!atomic_dec_and_mutex_lock(&event->mmap_count, &event->mmap_mutex))
4664 ring_buffer_attach(event, NULL);
4665 mutex_unlock(&event->mmap_mutex);
4667 /* If there's still other mmap()s of this buffer, we're done. */
4668 if (atomic_read(&rb->mmap_count))
4672 * No other mmap()s, detach from all other events that might redirect
4673 * into the now unreachable buffer. Somewhat complicated by the
4674 * fact that rb::event_lock otherwise nests inside mmap_mutex.
4678 list_for_each_entry_rcu(event, &rb->event_list, rb_entry) {
4679 if (!atomic_long_inc_not_zero(&event->refcount)) {
4681 * This event is en-route to free_event() which will
4682 * detach it and remove it from the list.
4688 mutex_lock(&event->mmap_mutex);
4690 * Check we didn't race with perf_event_set_output() which can
4691 * swizzle the rb from under us while we were waiting to
4692 * acquire mmap_mutex.
4694 * If we find a different rb; ignore this event, a next
4695 * iteration will no longer find it on the list. We have to
4696 * still restart the iteration to make sure we're not now
4697 * iterating the wrong list.
4699 if (event->rb == rb)
4700 ring_buffer_attach(event, NULL);
4702 mutex_unlock(&event->mmap_mutex);
4706 * Restart the iteration; either we're on the wrong list or
4707 * destroyed its integrity by doing a deletion.
4714 * It could be there's still a few 0-ref events on the list; they'll
4715 * get cleaned up by free_event() -- they'll also still have their
4716 * ref on the rb and will free it whenever they are done with it.
4718 * Aside from that, this buffer is 'fully' detached and unmapped,
4719 * undo the VM accounting.
4722 atomic_long_sub((size >> PAGE_SHIFT) + 1, &mmap_user->locked_vm);
4723 vma->vm_mm->pinned_vm -= mmap_locked;
4724 free_uid(mmap_user);
4727 ring_buffer_put(rb); /* could be last */
4730 static const struct vm_operations_struct perf_mmap_vmops = {
4731 .open = perf_mmap_open,
4732 .close = perf_mmap_close, /* non mergable */
4733 .fault = perf_mmap_fault,
4734 .page_mkwrite = perf_mmap_fault,
4737 static int perf_mmap(struct file *file, struct vm_area_struct *vma)
4739 struct perf_event *event = file->private_data;
4740 unsigned long user_locked, user_lock_limit;
4741 struct user_struct *user = current_user();
4742 unsigned long locked, lock_limit;
4743 struct ring_buffer *rb = NULL;
4744 unsigned long vma_size;
4745 unsigned long nr_pages;
4746 long user_extra = 0, extra = 0;
4747 int ret = 0, flags = 0;
4750 * Don't allow mmap() of inherited per-task counters. This would
4751 * create a performance issue due to all children writing to the
4754 if (event->cpu == -1 && event->attr.inherit)
4757 if (!(vma->vm_flags & VM_SHARED))
4760 vma_size = vma->vm_end - vma->vm_start;
4762 if (vma->vm_pgoff == 0) {
4763 nr_pages = (vma_size / PAGE_SIZE) - 1;
4766 * AUX area mapping: if rb->aux_nr_pages != 0, it's already
4767 * mapped, all subsequent mappings should have the same size
4768 * and offset. Must be above the normal perf buffer.
4770 u64 aux_offset, aux_size;
4775 nr_pages = vma_size / PAGE_SIZE;
4777 mutex_lock(&event->mmap_mutex);
4784 aux_offset = ACCESS_ONCE(rb->user_page->aux_offset);
4785 aux_size = ACCESS_ONCE(rb->user_page->aux_size);
4787 if (aux_offset < perf_data_size(rb) + PAGE_SIZE)
4790 if (aux_offset != vma->vm_pgoff << PAGE_SHIFT)
4793 /* already mapped with a different offset */
4794 if (rb_has_aux(rb) && rb->aux_pgoff != vma->vm_pgoff)
4797 if (aux_size != vma_size || aux_size != nr_pages * PAGE_SIZE)
4800 /* already mapped with a different size */
4801 if (rb_has_aux(rb) && rb->aux_nr_pages != nr_pages)
4804 if (!is_power_of_2(nr_pages))
4807 if (!atomic_inc_not_zero(&rb->mmap_count))
4810 if (rb_has_aux(rb)) {
4811 atomic_inc(&rb->aux_mmap_count);
4816 atomic_set(&rb->aux_mmap_count, 1);
4817 user_extra = nr_pages;
4823 * If we have rb pages ensure they're a power-of-two number, so we
4824 * can do bitmasks instead of modulo.
4826 if (nr_pages != 0 && !is_power_of_2(nr_pages))
4829 if (vma_size != PAGE_SIZE * (1 + nr_pages))
4832 WARN_ON_ONCE(event->ctx->parent_ctx);
4834 mutex_lock(&event->mmap_mutex);
4836 if (event->rb->nr_pages != nr_pages) {
4841 if (!atomic_inc_not_zero(&event->rb->mmap_count)) {
4843 * Raced against perf_mmap_close() through
4844 * perf_event_set_output(). Try again, hope for better
4847 mutex_unlock(&event->mmap_mutex);
4854 user_extra = nr_pages + 1;
4857 user_lock_limit = sysctl_perf_event_mlock >> (PAGE_SHIFT - 10);
4860 * Increase the limit linearly with more CPUs:
4862 user_lock_limit *= num_online_cpus();
4864 user_locked = atomic_long_read(&user->locked_vm) + user_extra;
4866 if (user_locked > user_lock_limit)
4867 extra = user_locked - user_lock_limit;
4869 lock_limit = rlimit(RLIMIT_MEMLOCK);
4870 lock_limit >>= PAGE_SHIFT;
4871 locked = vma->vm_mm->pinned_vm + extra;
4873 if ((locked > lock_limit) && perf_paranoid_tracepoint_raw() &&
4874 !capable(CAP_IPC_LOCK)) {
4879 WARN_ON(!rb && event->rb);
4881 if (vma->vm_flags & VM_WRITE)
4882 flags |= RING_BUFFER_WRITABLE;
4885 rb = rb_alloc(nr_pages,
4886 event->attr.watermark ? event->attr.wakeup_watermark : 0,
4894 atomic_set(&rb->mmap_count, 1);
4895 rb->mmap_user = get_current_user();
4896 rb->mmap_locked = extra;
4898 ring_buffer_attach(event, rb);
4900 perf_event_init_userpage(event);
4901 perf_event_update_userpage(event);
4903 ret = rb_alloc_aux(rb, event, vma->vm_pgoff, nr_pages,
4904 event->attr.aux_watermark, flags);
4906 rb->aux_mmap_locked = extra;
4911 atomic_long_add(user_extra, &user->locked_vm);
4912 vma->vm_mm->pinned_vm += extra;
4914 atomic_inc(&event->mmap_count);
4916 atomic_dec(&rb->mmap_count);
4919 mutex_unlock(&event->mmap_mutex);
4922 * Since pinned accounting is per vm we cannot allow fork() to copy our
4925 vma->vm_flags |= VM_DONTCOPY | VM_DONTEXPAND | VM_DONTDUMP;
4926 vma->vm_ops = &perf_mmap_vmops;
4928 if (event->pmu->event_mapped)
4929 event->pmu->event_mapped(event);
4934 static int perf_fasync(int fd, struct file *filp, int on)
4936 struct inode *inode = file_inode(filp);
4937 struct perf_event *event = filp->private_data;
4941 retval = fasync_helper(fd, filp, on, &event->fasync);
4942 inode_unlock(inode);
4950 static const struct file_operations perf_fops = {
4951 .llseek = no_llseek,
4952 .release = perf_release,
4955 .unlocked_ioctl = perf_ioctl,
4956 .compat_ioctl = perf_compat_ioctl,
4958 .fasync = perf_fasync,
4964 * If there's data, ensure we set the poll() state and publish everything
4965 * to user-space before waking everybody up.
4968 static inline struct fasync_struct **perf_event_fasync(struct perf_event *event)
4970 /* only the parent has fasync state */
4972 event = event->parent;
4973 return &event->fasync;
4976 void perf_event_wakeup(struct perf_event *event)
4978 ring_buffer_wakeup(event);
4980 if (event->pending_kill) {
4981 kill_fasync(perf_event_fasync(event), SIGIO, event->pending_kill);
4982 event->pending_kill = 0;
4986 static void perf_pending_event(struct irq_work *entry)
4988 struct perf_event *event = container_of(entry,
4989 struct perf_event, pending);
4992 rctx = perf_swevent_get_recursion_context();
4994 * If we 'fail' here, that's OK, it means recursion is already disabled
4995 * and we won't recurse 'further'.
4998 if (event->pending_disable) {
4999 event->pending_disable = 0;
5000 perf_event_disable_local(event);
5003 if (event->pending_wakeup) {
5004 event->pending_wakeup = 0;
5005 perf_event_wakeup(event);
5009 perf_swevent_put_recursion_context(rctx);
5013 * We assume there is only KVM supporting the callbacks.
5014 * Later on, we might change it to a list if there is
5015 * another virtualization implementation supporting the callbacks.
5017 struct perf_guest_info_callbacks *perf_guest_cbs;
5019 int perf_register_guest_info_callbacks(struct perf_guest_info_callbacks *cbs)
5021 perf_guest_cbs = cbs;
5024 EXPORT_SYMBOL_GPL(perf_register_guest_info_callbacks);
5026 int perf_unregister_guest_info_callbacks(struct perf_guest_info_callbacks *cbs)
5028 perf_guest_cbs = NULL;
5031 EXPORT_SYMBOL_GPL(perf_unregister_guest_info_callbacks);
5034 perf_output_sample_regs(struct perf_output_handle *handle,
5035 struct pt_regs *regs, u64 mask)
5039 for_each_set_bit(bit, (const unsigned long *) &mask,
5040 sizeof(mask) * BITS_PER_BYTE) {
5043 val = perf_reg_value(regs, bit);
5044 perf_output_put(handle, val);
5048 static void perf_sample_regs_user(struct perf_regs *regs_user,
5049 struct pt_regs *regs,
5050 struct pt_regs *regs_user_copy)
5052 if (user_mode(regs)) {
5053 regs_user->abi = perf_reg_abi(current);
5054 regs_user->regs = regs;
5055 } else if (current->mm) {
5056 perf_get_regs_user(regs_user, regs, regs_user_copy);
5058 regs_user->abi = PERF_SAMPLE_REGS_ABI_NONE;
5059 regs_user->regs = NULL;
5063 static void perf_sample_regs_intr(struct perf_regs *regs_intr,
5064 struct pt_regs *regs)
5066 regs_intr->regs = regs;
5067 regs_intr->abi = perf_reg_abi(current);
5072 * Get remaining task size from user stack pointer.
5074 * It'd be better to take stack vma map and limit this more
5075 * precisly, but there's no way to get it safely under interrupt,
5076 * so using TASK_SIZE as limit.
5078 static u64 perf_ustack_task_size(struct pt_regs *regs)
5080 unsigned long addr = perf_user_stack_pointer(regs);
5082 if (!addr || addr >= TASK_SIZE)
5085 return TASK_SIZE - addr;
5089 perf_sample_ustack_size(u16 stack_size, u16 header_size,
5090 struct pt_regs *regs)
5094 /* No regs, no stack pointer, no dump. */
5099 * Check if we fit in with the requested stack size into the:
5101 * If we don't, we limit the size to the TASK_SIZE.
5103 * - remaining sample size
5104 * If we don't, we customize the stack size to
5105 * fit in to the remaining sample size.
5108 task_size = min((u64) USHRT_MAX, perf_ustack_task_size(regs));
5109 stack_size = min(stack_size, (u16) task_size);
5111 /* Current header size plus static size and dynamic size. */
5112 header_size += 2 * sizeof(u64);
5114 /* Do we fit in with the current stack dump size? */
5115 if ((u16) (header_size + stack_size) < header_size) {
5117 * If we overflow the maximum size for the sample,
5118 * we customize the stack dump size to fit in.
5120 stack_size = USHRT_MAX - header_size - sizeof(u64);
5121 stack_size = round_up(stack_size, sizeof(u64));
5128 perf_output_sample_ustack(struct perf_output_handle *handle, u64 dump_size,
5129 struct pt_regs *regs)
5131 /* Case of a kernel thread, nothing to dump */
5134 perf_output_put(handle, size);
5143 * - the size requested by user or the best one we can fit
5144 * in to the sample max size
5146 * - user stack dump data
5148 * - the actual dumped size
5152 perf_output_put(handle, dump_size);
5155 sp = perf_user_stack_pointer(regs);
5156 rem = __output_copy_user(handle, (void *) sp, dump_size);
5157 dyn_size = dump_size - rem;
5159 perf_output_skip(handle, rem);
5162 perf_output_put(handle, dyn_size);
5166 static void __perf_event_header__init_id(struct perf_event_header *header,
5167 struct perf_sample_data *data,
5168 struct perf_event *event)
5170 u64 sample_type = event->attr.sample_type;
5172 data->type = sample_type;
5173 header->size += event->id_header_size;
5175 if (sample_type & PERF_SAMPLE_TID) {
5176 /* namespace issues */
5177 data->tid_entry.pid = perf_event_pid(event, current);
5178 data->tid_entry.tid = perf_event_tid(event, current);
5181 if (sample_type & PERF_SAMPLE_TIME)
5182 data->time = perf_event_clock(event);
5184 if (sample_type & (PERF_SAMPLE_ID | PERF_SAMPLE_IDENTIFIER))
5185 data->id = primary_event_id(event);
5187 if (sample_type & PERF_SAMPLE_STREAM_ID)
5188 data->stream_id = event->id;
5190 if (sample_type & PERF_SAMPLE_CPU) {
5191 data->cpu_entry.cpu = raw_smp_processor_id();
5192 data->cpu_entry.reserved = 0;
5196 void perf_event_header__init_id(struct perf_event_header *header,
5197 struct perf_sample_data *data,
5198 struct perf_event *event)
5200 if (event->attr.sample_id_all)
5201 __perf_event_header__init_id(header, data, event);
5204 static void __perf_event__output_id_sample(struct perf_output_handle *handle,
5205 struct perf_sample_data *data)
5207 u64 sample_type = data->type;
5209 if (sample_type & PERF_SAMPLE_TID)
5210 perf_output_put(handle, data->tid_entry);
5212 if (sample_type & PERF_SAMPLE_TIME)
5213 perf_output_put(handle, data->time);
5215 if (sample_type & PERF_SAMPLE_ID)
5216 perf_output_put(handle, data->id);
5218 if (sample_type & PERF_SAMPLE_STREAM_ID)
5219 perf_output_put(handle, data->stream_id);
5221 if (sample_type & PERF_SAMPLE_CPU)
5222 perf_output_put(handle, data->cpu_entry);
5224 if (sample_type & PERF_SAMPLE_IDENTIFIER)
5225 perf_output_put(handle, data->id);
5228 void perf_event__output_id_sample(struct perf_event *event,
5229 struct perf_output_handle *handle,
5230 struct perf_sample_data *sample)
5232 if (event->attr.sample_id_all)
5233 __perf_event__output_id_sample(handle, sample);
5236 static void perf_output_read_one(struct perf_output_handle *handle,
5237 struct perf_event *event,
5238 u64 enabled, u64 running)
5240 u64 read_format = event->attr.read_format;
5244 values[n++] = perf_event_count(event);
5245 if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED) {
5246 values[n++] = enabled +
5247 atomic64_read(&event->child_total_time_enabled);
5249 if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING) {
5250 values[n++] = running +
5251 atomic64_read(&event->child_total_time_running);
5253 if (read_format & PERF_FORMAT_ID)
5254 values[n++] = primary_event_id(event);
5256 __output_copy(handle, values, n * sizeof(u64));
5260 * XXX PERF_FORMAT_GROUP vs inherited events seems difficult.
5262 static void perf_output_read_group(struct perf_output_handle *handle,
5263 struct perf_event *event,
5264 u64 enabled, u64 running)
5266 struct perf_event *leader = event->group_leader, *sub;
5267 u64 read_format = event->attr.read_format;
5271 values[n++] = 1 + leader->nr_siblings;
5273 if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED)
5274 values[n++] = enabled;
5276 if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING)
5277 values[n++] = running;
5279 if (leader != event)
5280 leader->pmu->read(leader);
5282 values[n++] = perf_event_count(leader);
5283 if (read_format & PERF_FORMAT_ID)
5284 values[n++] = primary_event_id(leader);
5286 __output_copy(handle, values, n * sizeof(u64));
5288 list_for_each_entry(sub, &leader->sibling_list, group_entry) {
5291 if ((sub != event) &&
5292 (sub->state == PERF_EVENT_STATE_ACTIVE))
5293 sub->pmu->read(sub);
5295 values[n++] = perf_event_count(sub);
5296 if (read_format & PERF_FORMAT_ID)
5297 values[n++] = primary_event_id(sub);
5299 __output_copy(handle, values, n * sizeof(u64));
5303 #define PERF_FORMAT_TOTAL_TIMES (PERF_FORMAT_TOTAL_TIME_ENABLED|\
5304 PERF_FORMAT_TOTAL_TIME_RUNNING)
5306 static void perf_output_read(struct perf_output_handle *handle,
5307 struct perf_event *event)
5309 u64 enabled = 0, running = 0, now;
5310 u64 read_format = event->attr.read_format;
5313 * compute total_time_enabled, total_time_running
5314 * based on snapshot values taken when the event
5315 * was last scheduled in.
5317 * we cannot simply called update_context_time()
5318 * because of locking issue as we are called in
5321 if (read_format & PERF_FORMAT_TOTAL_TIMES)
5322 calc_timer_values(event, &now, &enabled, &running);
5324 if (event->attr.read_format & PERF_FORMAT_GROUP)
5325 perf_output_read_group(handle, event, enabled, running);
5327 perf_output_read_one(handle, event, enabled, running);
5330 void perf_output_sample(struct perf_output_handle *handle,
5331 struct perf_event_header *header,
5332 struct perf_sample_data *data,
5333 struct perf_event *event)
5335 u64 sample_type = data->type;
5337 perf_output_put(handle, *header);
5339 if (sample_type & PERF_SAMPLE_IDENTIFIER)
5340 perf_output_put(handle, data->id);
5342 if (sample_type & PERF_SAMPLE_IP)
5343 perf_output_put(handle, data->ip);
5345 if (sample_type & PERF_SAMPLE_TID)
5346 perf_output_put(handle, data->tid_entry);
5348 if (sample_type & PERF_SAMPLE_TIME)
5349 perf_output_put(handle, data->time);
5351 if (sample_type & PERF_SAMPLE_ADDR)
5352 perf_output_put(handle, data->addr);
5354 if (sample_type & PERF_SAMPLE_ID)
5355 perf_output_put(handle, data->id);
5357 if (sample_type & PERF_SAMPLE_STREAM_ID)
5358 perf_output_put(handle, data->stream_id);
5360 if (sample_type & PERF_SAMPLE_CPU)
5361 perf_output_put(handle, data->cpu_entry);
5363 if (sample_type & PERF_SAMPLE_PERIOD)
5364 perf_output_put(handle, data->period);
5366 if (sample_type & PERF_SAMPLE_READ)
5367 perf_output_read(handle, event);
5369 if (sample_type & PERF_SAMPLE_CALLCHAIN) {
5370 if (data->callchain) {
5373 if (data->callchain)
5374 size += data->callchain->nr;
5376 size *= sizeof(u64);
5378 __output_copy(handle, data->callchain, size);
5381 perf_output_put(handle, nr);
5385 if (sample_type & PERF_SAMPLE_RAW) {
5387 u32 raw_size = data->raw->size;
5388 u32 real_size = round_up(raw_size + sizeof(u32),
5389 sizeof(u64)) - sizeof(u32);
5392 perf_output_put(handle, real_size);
5393 __output_copy(handle, data->raw->data, raw_size);
5394 if (real_size - raw_size)
5395 __output_copy(handle, &zero, real_size - raw_size);
5401 .size = sizeof(u32),
5404 perf_output_put(handle, raw);
5408 if (sample_type & PERF_SAMPLE_BRANCH_STACK) {
5409 if (data->br_stack) {
5412 size = data->br_stack->nr
5413 * sizeof(struct perf_branch_entry);
5415 perf_output_put(handle, data->br_stack->nr);
5416 perf_output_copy(handle, data->br_stack->entries, size);
5419 * we always store at least the value of nr
5422 perf_output_put(handle, nr);
5426 if (sample_type & PERF_SAMPLE_REGS_USER) {
5427 u64 abi = data->regs_user.abi;
5430 * If there are no regs to dump, notice it through
5431 * first u64 being zero (PERF_SAMPLE_REGS_ABI_NONE).
5433 perf_output_put(handle, abi);
5436 u64 mask = event->attr.sample_regs_user;
5437 perf_output_sample_regs(handle,
5438 data->regs_user.regs,
5443 if (sample_type & PERF_SAMPLE_STACK_USER) {
5444 perf_output_sample_ustack(handle,
5445 data->stack_user_size,
5446 data->regs_user.regs);
5449 if (sample_type & PERF_SAMPLE_WEIGHT)
5450 perf_output_put(handle, data->weight);
5452 if (sample_type & PERF_SAMPLE_DATA_SRC)
5453 perf_output_put(handle, data->data_src.val);
5455 if (sample_type & PERF_SAMPLE_TRANSACTION)
5456 perf_output_put(handle, data->txn);
5458 if (sample_type & PERF_SAMPLE_REGS_INTR) {
5459 u64 abi = data->regs_intr.abi;
5461 * If there are no regs to dump, notice it through
5462 * first u64 being zero (PERF_SAMPLE_REGS_ABI_NONE).
5464 perf_output_put(handle, abi);
5467 u64 mask = event->attr.sample_regs_intr;
5469 perf_output_sample_regs(handle,
5470 data->regs_intr.regs,
5475 if (!event->attr.watermark) {
5476 int wakeup_events = event->attr.wakeup_events;
5478 if (wakeup_events) {
5479 struct ring_buffer *rb = handle->rb;
5480 int events = local_inc_return(&rb->events);
5482 if (events >= wakeup_events) {
5483 local_sub(wakeup_events, &rb->events);
5484 local_inc(&rb->wakeup);
5490 void perf_prepare_sample(struct perf_event_header *header,
5491 struct perf_sample_data *data,
5492 struct perf_event *event,
5493 struct pt_regs *regs)
5495 u64 sample_type = event->attr.sample_type;
5497 header->type = PERF_RECORD_SAMPLE;
5498 header->size = sizeof(*header) + event->header_size;
5501 header->misc |= perf_misc_flags(regs);
5503 __perf_event_header__init_id(header, data, event);
5505 if (sample_type & PERF_SAMPLE_IP)
5506 data->ip = perf_instruction_pointer(regs);
5508 if (sample_type & PERF_SAMPLE_CALLCHAIN) {
5511 data->callchain = perf_callchain(event, regs);
5513 if (data->callchain)
5514 size += data->callchain->nr;
5516 header->size += size * sizeof(u64);
5519 if (sample_type & PERF_SAMPLE_RAW) {
5520 int size = sizeof(u32);
5523 size += data->raw->size;
5525 size += sizeof(u32);
5527 header->size += round_up(size, sizeof(u64));
5530 if (sample_type & PERF_SAMPLE_BRANCH_STACK) {
5531 int size = sizeof(u64); /* nr */
5532 if (data->br_stack) {
5533 size += data->br_stack->nr
5534 * sizeof(struct perf_branch_entry);
5536 header->size += size;
5539 if (sample_type & (PERF_SAMPLE_REGS_USER | PERF_SAMPLE_STACK_USER))
5540 perf_sample_regs_user(&data->regs_user, regs,
5541 &data->regs_user_copy);
5543 if (sample_type & PERF_SAMPLE_REGS_USER) {
5544 /* regs dump ABI info */
5545 int size = sizeof(u64);
5547 if (data->regs_user.regs) {
5548 u64 mask = event->attr.sample_regs_user;
5549 size += hweight64(mask) * sizeof(u64);
5552 header->size += size;
5555 if (sample_type & PERF_SAMPLE_STACK_USER) {
5557 * Either we need PERF_SAMPLE_STACK_USER bit to be allways
5558 * processed as the last one or have additional check added
5559 * in case new sample type is added, because we could eat
5560 * up the rest of the sample size.
5562 u16 stack_size = event->attr.sample_stack_user;
5563 u16 size = sizeof(u64);
5565 stack_size = perf_sample_ustack_size(stack_size, header->size,
5566 data->regs_user.regs);
5569 * If there is something to dump, add space for the dump
5570 * itself and for the field that tells the dynamic size,
5571 * which is how many have been actually dumped.
5574 size += sizeof(u64) + stack_size;
5576 data->stack_user_size = stack_size;
5577 header->size += size;
5580 if (sample_type & PERF_SAMPLE_REGS_INTR) {
5581 /* regs dump ABI info */
5582 int size = sizeof(u64);
5584 perf_sample_regs_intr(&data->regs_intr, regs);
5586 if (data->regs_intr.regs) {
5587 u64 mask = event->attr.sample_regs_intr;
5589 size += hweight64(mask) * sizeof(u64);
5592 header->size += size;
5596 void perf_event_output(struct perf_event *event,
5597 struct perf_sample_data *data,
5598 struct pt_regs *regs)
5600 struct perf_output_handle handle;
5601 struct perf_event_header header;
5603 /* protect the callchain buffers */
5606 perf_prepare_sample(&header, data, event, regs);
5608 if (perf_output_begin(&handle, event, header.size))
5611 perf_output_sample(&handle, &header, data, event);
5613 perf_output_end(&handle);
5623 struct perf_read_event {
5624 struct perf_event_header header;
5631 perf_event_read_event(struct perf_event *event,
5632 struct task_struct *task)
5634 struct perf_output_handle handle;
5635 struct perf_sample_data sample;
5636 struct perf_read_event read_event = {
5638 .type = PERF_RECORD_READ,
5640 .size = sizeof(read_event) + event->read_size,
5642 .pid = perf_event_pid(event, task),
5643 .tid = perf_event_tid(event, task),
5647 perf_event_header__init_id(&read_event.header, &sample, event);
5648 ret = perf_output_begin(&handle, event, read_event.header.size);
5652 perf_output_put(&handle, read_event);
5653 perf_output_read(&handle, event);
5654 perf_event__output_id_sample(event, &handle, &sample);
5656 perf_output_end(&handle);
5659 typedef void (perf_event_aux_output_cb)(struct perf_event *event, void *data);
5662 perf_event_aux_ctx(struct perf_event_context *ctx,
5663 perf_event_aux_output_cb output,
5666 struct perf_event *event;
5668 list_for_each_entry_rcu(event, &ctx->event_list, event_entry) {
5669 if (event->state < PERF_EVENT_STATE_INACTIVE)
5671 if (!event_filter_match(event))
5673 output(event, data);
5678 perf_event_aux_task_ctx(perf_event_aux_output_cb output, void *data,
5679 struct perf_event_context *task_ctx)
5683 perf_event_aux_ctx(task_ctx, output, data);
5689 perf_event_aux(perf_event_aux_output_cb output, void *data,
5690 struct perf_event_context *task_ctx)
5692 struct perf_cpu_context *cpuctx;
5693 struct perf_event_context *ctx;
5698 * If we have task_ctx != NULL we only notify
5699 * the task context itself. The task_ctx is set
5700 * only for EXIT events before releasing task
5704 perf_event_aux_task_ctx(output, data, task_ctx);
5709 list_for_each_entry_rcu(pmu, &pmus, entry) {
5710 cpuctx = get_cpu_ptr(pmu->pmu_cpu_context);
5711 if (cpuctx->unique_pmu != pmu)
5713 perf_event_aux_ctx(&cpuctx->ctx, output, data);
5714 ctxn = pmu->task_ctx_nr;
5717 ctx = rcu_dereference(current->perf_event_ctxp[ctxn]);
5719 perf_event_aux_ctx(ctx, output, data);
5721 put_cpu_ptr(pmu->pmu_cpu_context);
5727 * task tracking -- fork/exit
5729 * enabled by: attr.comm | attr.mmap | attr.mmap2 | attr.mmap_data | attr.task
5732 struct perf_task_event {
5733 struct task_struct *task;
5734 struct perf_event_context *task_ctx;
5737 struct perf_event_header header;
5747 static int perf_event_task_match(struct perf_event *event)
5749 return event->attr.comm || event->attr.mmap ||
5750 event->attr.mmap2 || event->attr.mmap_data ||
5754 static void perf_event_task_output(struct perf_event *event,
5757 struct perf_task_event *task_event = data;
5758 struct perf_output_handle handle;
5759 struct perf_sample_data sample;
5760 struct task_struct *task = task_event->task;
5761 int ret, size = task_event->event_id.header.size;
5763 if (!perf_event_task_match(event))
5766 perf_event_header__init_id(&task_event->event_id.header, &sample, event);
5768 ret = perf_output_begin(&handle, event,
5769 task_event->event_id.header.size);
5773 task_event->event_id.pid = perf_event_pid(event, task);
5774 task_event->event_id.ppid = perf_event_pid(event, current);
5776 task_event->event_id.tid = perf_event_tid(event, task);
5777 task_event->event_id.ptid = perf_event_tid(event, current);
5779 task_event->event_id.time = perf_event_clock(event);
5781 perf_output_put(&handle, task_event->event_id);
5783 perf_event__output_id_sample(event, &handle, &sample);
5785 perf_output_end(&handle);
5787 task_event->event_id.header.size = size;
5790 static void perf_event_task(struct task_struct *task,
5791 struct perf_event_context *task_ctx,
5794 struct perf_task_event task_event;
5796 if (!atomic_read(&nr_comm_events) &&
5797 !atomic_read(&nr_mmap_events) &&
5798 !atomic_read(&nr_task_events))
5801 task_event = (struct perf_task_event){
5803 .task_ctx = task_ctx,
5806 .type = new ? PERF_RECORD_FORK : PERF_RECORD_EXIT,
5808 .size = sizeof(task_event.event_id),
5818 perf_event_aux(perf_event_task_output,
5823 void perf_event_fork(struct task_struct *task)
5825 perf_event_task(task, NULL, 1);
5832 struct perf_comm_event {
5833 struct task_struct *task;
5838 struct perf_event_header header;
5845 static int perf_event_comm_match(struct perf_event *event)
5847 return event->attr.comm;
5850 static void perf_event_comm_output(struct perf_event *event,
5853 struct perf_comm_event *comm_event = data;
5854 struct perf_output_handle handle;
5855 struct perf_sample_data sample;
5856 int size = comm_event->event_id.header.size;
5859 if (!perf_event_comm_match(event))
5862 perf_event_header__init_id(&comm_event->event_id.header, &sample, event);
5863 ret = perf_output_begin(&handle, event,
5864 comm_event->event_id.header.size);
5869 comm_event->event_id.pid = perf_event_pid(event, comm_event->task);
5870 comm_event->event_id.tid = perf_event_tid(event, comm_event->task);
5872 perf_output_put(&handle, comm_event->event_id);
5873 __output_copy(&handle, comm_event->comm,
5874 comm_event->comm_size);
5876 perf_event__output_id_sample(event, &handle, &sample);
5878 perf_output_end(&handle);
5880 comm_event->event_id.header.size = size;
5883 static void perf_event_comm_event(struct perf_comm_event *comm_event)
5885 char comm[TASK_COMM_LEN];
5888 memset(comm, 0, sizeof(comm));
5889 strlcpy(comm, comm_event->task->comm, sizeof(comm));
5890 size = ALIGN(strlen(comm)+1, sizeof(u64));
5892 comm_event->comm = comm;
5893 comm_event->comm_size = size;
5895 comm_event->event_id.header.size = sizeof(comm_event->event_id) + size;
5897 perf_event_aux(perf_event_comm_output,
5902 void perf_event_comm(struct task_struct *task, bool exec)
5904 struct perf_comm_event comm_event;
5906 if (!atomic_read(&nr_comm_events))
5909 comm_event = (struct perf_comm_event){
5915 .type = PERF_RECORD_COMM,
5916 .misc = exec ? PERF_RECORD_MISC_COMM_EXEC : 0,
5924 perf_event_comm_event(&comm_event);
5931 struct perf_mmap_event {
5932 struct vm_area_struct *vma;
5934 const char *file_name;
5942 struct perf_event_header header;
5952 static int perf_event_mmap_match(struct perf_event *event,
5955 struct perf_mmap_event *mmap_event = data;
5956 struct vm_area_struct *vma = mmap_event->vma;
5957 int executable = vma->vm_flags & VM_EXEC;
5959 return (!executable && event->attr.mmap_data) ||
5960 (executable && (event->attr.mmap || event->attr.mmap2));
5963 static void perf_event_mmap_output(struct perf_event *event,
5966 struct perf_mmap_event *mmap_event = data;
5967 struct perf_output_handle handle;
5968 struct perf_sample_data sample;
5969 int size = mmap_event->event_id.header.size;
5972 if (!perf_event_mmap_match(event, data))
5975 if (event->attr.mmap2) {
5976 mmap_event->event_id.header.type = PERF_RECORD_MMAP2;
5977 mmap_event->event_id.header.size += sizeof(mmap_event->maj);
5978 mmap_event->event_id.header.size += sizeof(mmap_event->min);
5979 mmap_event->event_id.header.size += sizeof(mmap_event->ino);
5980 mmap_event->event_id.header.size += sizeof(mmap_event->ino_generation);
5981 mmap_event->event_id.header.size += sizeof(mmap_event->prot);
5982 mmap_event->event_id.header.size += sizeof(mmap_event->flags);
5985 perf_event_header__init_id(&mmap_event->event_id.header, &sample, event);
5986 ret = perf_output_begin(&handle, event,
5987 mmap_event->event_id.header.size);
5991 mmap_event->event_id.pid = perf_event_pid(event, current);
5992 mmap_event->event_id.tid = perf_event_tid(event, current);
5994 perf_output_put(&handle, mmap_event->event_id);
5996 if (event->attr.mmap2) {
5997 perf_output_put(&handle, mmap_event->maj);
5998 perf_output_put(&handle, mmap_event->min);
5999 perf_output_put(&handle, mmap_event->ino);
6000 perf_output_put(&handle, mmap_event->ino_generation);
6001 perf_output_put(&handle, mmap_event->prot);
6002 perf_output_put(&handle, mmap_event->flags);
6005 __output_copy(&handle, mmap_event->file_name,
6006 mmap_event->file_size);
6008 perf_event__output_id_sample(event, &handle, &sample);
6010 perf_output_end(&handle);
6012 mmap_event->event_id.header.size = size;
6015 static void perf_event_mmap_event(struct perf_mmap_event *mmap_event)
6017 struct vm_area_struct *vma = mmap_event->vma;
6018 struct file *file = vma->vm_file;
6019 int maj = 0, min = 0;
6020 u64 ino = 0, gen = 0;
6021 u32 prot = 0, flags = 0;
6028 struct inode *inode;
6031 buf = kmalloc(PATH_MAX, GFP_KERNEL);
6037 * d_path() works from the end of the rb backwards, so we
6038 * need to add enough zero bytes after the string to handle
6039 * the 64bit alignment we do later.
6041 name = file_path(file, buf, PATH_MAX - sizeof(u64));
6046 inode = file_inode(vma->vm_file);
6047 dev = inode->i_sb->s_dev;
6049 gen = inode->i_generation;
6053 if (vma->vm_flags & VM_READ)
6055 if (vma->vm_flags & VM_WRITE)
6057 if (vma->vm_flags & VM_EXEC)
6060 if (vma->vm_flags & VM_MAYSHARE)
6063 flags = MAP_PRIVATE;
6065 if (vma->vm_flags & VM_DENYWRITE)
6066 flags |= MAP_DENYWRITE;
6067 if (vma->vm_flags & VM_MAYEXEC)
6068 flags |= MAP_EXECUTABLE;
6069 if (vma->vm_flags & VM_LOCKED)
6070 flags |= MAP_LOCKED;
6071 if (vma->vm_flags & VM_HUGETLB)
6072 flags |= MAP_HUGETLB;
6076 if (vma->vm_ops && vma->vm_ops->name) {
6077 name = (char *) vma->vm_ops->name(vma);
6082 name = (char *)arch_vma_name(vma);
6086 if (vma->vm_start <= vma->vm_mm->start_brk &&
6087 vma->vm_end >= vma->vm_mm->brk) {
6091 if (vma->vm_start <= vma->vm_mm->start_stack &&
6092 vma->vm_end >= vma->vm_mm->start_stack) {
6102 strlcpy(tmp, name, sizeof(tmp));
6106 * Since our buffer works in 8 byte units we need to align our string
6107 * size to a multiple of 8. However, we must guarantee the tail end is
6108 * zero'd out to avoid leaking random bits to userspace.
6110 size = strlen(name)+1;
6111 while (!IS_ALIGNED(size, sizeof(u64)))
6112 name[size++] = '\0';
6114 mmap_event->file_name = name;
6115 mmap_event->file_size = size;
6116 mmap_event->maj = maj;
6117 mmap_event->min = min;
6118 mmap_event->ino = ino;
6119 mmap_event->ino_generation = gen;
6120 mmap_event->prot = prot;
6121 mmap_event->flags = flags;
6123 if (!(vma->vm_flags & VM_EXEC))
6124 mmap_event->event_id.header.misc |= PERF_RECORD_MISC_MMAP_DATA;
6126 mmap_event->event_id.header.size = sizeof(mmap_event->event_id) + size;
6128 perf_event_aux(perf_event_mmap_output,
6135 void perf_event_mmap(struct vm_area_struct *vma)
6137 struct perf_mmap_event mmap_event;
6139 if (!atomic_read(&nr_mmap_events))
6142 mmap_event = (struct perf_mmap_event){
6148 .type = PERF_RECORD_MMAP,
6149 .misc = PERF_RECORD_MISC_USER,
6154 .start = vma->vm_start,
6155 .len = vma->vm_end - vma->vm_start,
6156 .pgoff = (u64)vma->vm_pgoff << PAGE_SHIFT,
6158 /* .maj (attr_mmap2 only) */
6159 /* .min (attr_mmap2 only) */
6160 /* .ino (attr_mmap2 only) */
6161 /* .ino_generation (attr_mmap2 only) */
6162 /* .prot (attr_mmap2 only) */
6163 /* .flags (attr_mmap2 only) */
6166 perf_event_mmap_event(&mmap_event);
6169 void perf_event_aux_event(struct perf_event *event, unsigned long head,
6170 unsigned long size, u64 flags)
6172 struct perf_output_handle handle;
6173 struct perf_sample_data sample;
6174 struct perf_aux_event {
6175 struct perf_event_header header;
6181 .type = PERF_RECORD_AUX,
6183 .size = sizeof(rec),
6191 perf_event_header__init_id(&rec.header, &sample, event);
6192 ret = perf_output_begin(&handle, event, rec.header.size);
6197 perf_output_put(&handle, rec);
6198 perf_event__output_id_sample(event, &handle, &sample);
6200 perf_output_end(&handle);
6204 * Lost/dropped samples logging
6206 void perf_log_lost_samples(struct perf_event *event, u64 lost)
6208 struct perf_output_handle handle;
6209 struct perf_sample_data sample;
6213 struct perf_event_header header;
6215 } lost_samples_event = {
6217 .type = PERF_RECORD_LOST_SAMPLES,
6219 .size = sizeof(lost_samples_event),
6224 perf_event_header__init_id(&lost_samples_event.header, &sample, event);
6226 ret = perf_output_begin(&handle, event,
6227 lost_samples_event.header.size);
6231 perf_output_put(&handle, lost_samples_event);
6232 perf_event__output_id_sample(event, &handle, &sample);
6233 perf_output_end(&handle);
6237 * context_switch tracking
6240 struct perf_switch_event {
6241 struct task_struct *task;
6242 struct task_struct *next_prev;
6245 struct perf_event_header header;
6251 static int perf_event_switch_match(struct perf_event *event)
6253 return event->attr.context_switch;
6256 static void perf_event_switch_output(struct perf_event *event, void *data)
6258 struct perf_switch_event *se = data;
6259 struct perf_output_handle handle;
6260 struct perf_sample_data sample;
6263 if (!perf_event_switch_match(event))
6266 /* Only CPU-wide events are allowed to see next/prev pid/tid */
6267 if (event->ctx->task) {
6268 se->event_id.header.type = PERF_RECORD_SWITCH;
6269 se->event_id.header.size = sizeof(se->event_id.header);
6271 se->event_id.header.type = PERF_RECORD_SWITCH_CPU_WIDE;
6272 se->event_id.header.size = sizeof(se->event_id);
6273 se->event_id.next_prev_pid =
6274 perf_event_pid(event, se->next_prev);
6275 se->event_id.next_prev_tid =
6276 perf_event_tid(event, se->next_prev);
6279 perf_event_header__init_id(&se->event_id.header, &sample, event);
6281 ret = perf_output_begin(&handle, event, se->event_id.header.size);
6285 if (event->ctx->task)
6286 perf_output_put(&handle, se->event_id.header);
6288 perf_output_put(&handle, se->event_id);
6290 perf_event__output_id_sample(event, &handle, &sample);
6292 perf_output_end(&handle);
6295 static void perf_event_switch(struct task_struct *task,
6296 struct task_struct *next_prev, bool sched_in)
6298 struct perf_switch_event switch_event;
6300 /* N.B. caller checks nr_switch_events != 0 */
6302 switch_event = (struct perf_switch_event){
6304 .next_prev = next_prev,
6308 .misc = sched_in ? 0 : PERF_RECORD_MISC_SWITCH_OUT,
6311 /* .next_prev_pid */
6312 /* .next_prev_tid */
6316 perf_event_aux(perf_event_switch_output,
6322 * IRQ throttle logging
6325 static void perf_log_throttle(struct perf_event *event, int enable)
6327 struct perf_output_handle handle;
6328 struct perf_sample_data sample;
6332 struct perf_event_header header;
6336 } throttle_event = {
6338 .type = PERF_RECORD_THROTTLE,
6340 .size = sizeof(throttle_event),
6342 .time = perf_event_clock(event),
6343 .id = primary_event_id(event),
6344 .stream_id = event->id,
6348 throttle_event.header.type = PERF_RECORD_UNTHROTTLE;
6350 perf_event_header__init_id(&throttle_event.header, &sample, event);
6352 ret = perf_output_begin(&handle, event,
6353 throttle_event.header.size);
6357 perf_output_put(&handle, throttle_event);
6358 perf_event__output_id_sample(event, &handle, &sample);
6359 perf_output_end(&handle);
6362 static void perf_log_itrace_start(struct perf_event *event)
6364 struct perf_output_handle handle;
6365 struct perf_sample_data sample;
6366 struct perf_aux_event {
6367 struct perf_event_header header;
6374 event = event->parent;
6376 if (!(event->pmu->capabilities & PERF_PMU_CAP_ITRACE) ||
6377 event->hw.itrace_started)
6380 rec.header.type = PERF_RECORD_ITRACE_START;
6381 rec.header.misc = 0;
6382 rec.header.size = sizeof(rec);
6383 rec.pid = perf_event_pid(event, current);
6384 rec.tid = perf_event_tid(event, current);
6386 perf_event_header__init_id(&rec.header, &sample, event);
6387 ret = perf_output_begin(&handle, event, rec.header.size);
6392 perf_output_put(&handle, rec);
6393 perf_event__output_id_sample(event, &handle, &sample);
6395 perf_output_end(&handle);
6399 * Generic event overflow handling, sampling.
6402 static int __perf_event_overflow(struct perf_event *event,
6403 int throttle, struct perf_sample_data *data,
6404 struct pt_regs *regs)
6406 int events = atomic_read(&event->event_limit);
6407 struct hw_perf_event *hwc = &event->hw;
6412 * Non-sampling counters might still use the PMI to fold short
6413 * hardware counters, ignore those.
6415 if (unlikely(!is_sampling_event(event)))
6418 seq = __this_cpu_read(perf_throttled_seq);
6419 if (seq != hwc->interrupts_seq) {
6420 hwc->interrupts_seq = seq;
6421 hwc->interrupts = 1;
6424 if (unlikely(throttle
6425 && hwc->interrupts >= max_samples_per_tick)) {
6426 __this_cpu_inc(perf_throttled_count);
6427 hwc->interrupts = MAX_INTERRUPTS;
6428 perf_log_throttle(event, 0);
6429 tick_nohz_full_kick();
6434 if (event->attr.freq) {
6435 u64 now = perf_clock();
6436 s64 delta = now - hwc->freq_time_stamp;
6438 hwc->freq_time_stamp = now;
6440 if (delta > 0 && delta < 2*TICK_NSEC)
6441 perf_adjust_period(event, delta, hwc->last_period, true);
6445 * XXX event_limit might not quite work as expected on inherited
6449 event->pending_kill = POLL_IN;
6450 if (events && atomic_dec_and_test(&event->event_limit)) {
6452 event->pending_kill = POLL_HUP;
6453 event->pending_disable = 1;
6454 irq_work_queue(&event->pending);
6457 if (event->overflow_handler)
6458 event->overflow_handler(event, data, regs);
6460 perf_event_output(event, data, regs);
6462 if (*perf_event_fasync(event) && event->pending_kill) {
6463 event->pending_wakeup = 1;
6464 irq_work_queue(&event->pending);
6470 int perf_event_overflow(struct perf_event *event,
6471 struct perf_sample_data *data,
6472 struct pt_regs *regs)
6474 return __perf_event_overflow(event, 1, data, regs);
6478 * Generic software event infrastructure
6481 struct swevent_htable {
6482 struct swevent_hlist *swevent_hlist;
6483 struct mutex hlist_mutex;
6486 /* Recursion avoidance in each contexts */
6487 int recursion[PERF_NR_CONTEXTS];
6490 static DEFINE_PER_CPU(struct swevent_htable, swevent_htable);
6493 * We directly increment event->count and keep a second value in
6494 * event->hw.period_left to count intervals. This period event
6495 * is kept in the range [-sample_period, 0] so that we can use the
6499 u64 perf_swevent_set_period(struct perf_event *event)
6501 struct hw_perf_event *hwc = &event->hw;
6502 u64 period = hwc->last_period;
6506 hwc->last_period = hwc->sample_period;
6509 old = val = local64_read(&hwc->period_left);
6513 nr = div64_u64(period + val, period);
6514 offset = nr * period;
6516 if (local64_cmpxchg(&hwc->period_left, old, val) != old)
6522 static void perf_swevent_overflow(struct perf_event *event, u64 overflow,
6523 struct perf_sample_data *data,
6524 struct pt_regs *regs)
6526 struct hw_perf_event *hwc = &event->hw;
6530 overflow = perf_swevent_set_period(event);
6532 if (hwc->interrupts == MAX_INTERRUPTS)
6535 for (; overflow; overflow--) {
6536 if (__perf_event_overflow(event, throttle,
6539 * We inhibit the overflow from happening when
6540 * hwc->interrupts == MAX_INTERRUPTS.
6548 static void perf_swevent_event(struct perf_event *event, u64 nr,
6549 struct perf_sample_data *data,
6550 struct pt_regs *regs)
6552 struct hw_perf_event *hwc = &event->hw;
6554 local64_add(nr, &event->count);
6559 if (!is_sampling_event(event))
6562 if ((event->attr.sample_type & PERF_SAMPLE_PERIOD) && !event->attr.freq) {
6564 return perf_swevent_overflow(event, 1, data, regs);
6566 data->period = event->hw.last_period;
6568 if (nr == 1 && hwc->sample_period == 1 && !event->attr.freq)
6569 return perf_swevent_overflow(event, 1, data, regs);
6571 if (local64_add_negative(nr, &hwc->period_left))
6574 perf_swevent_overflow(event, 0, data, regs);
6577 static int perf_exclude_event(struct perf_event *event,
6578 struct pt_regs *regs)
6580 if (event->hw.state & PERF_HES_STOPPED)
6584 if (event->attr.exclude_user && user_mode(regs))
6587 if (event->attr.exclude_kernel && !user_mode(regs))
6594 static int perf_swevent_match(struct perf_event *event,
6595 enum perf_type_id type,
6597 struct perf_sample_data *data,
6598 struct pt_regs *regs)
6600 if (event->attr.type != type)
6603 if (event->attr.config != event_id)
6606 if (perf_exclude_event(event, regs))
6612 static inline u64 swevent_hash(u64 type, u32 event_id)
6614 u64 val = event_id | (type << 32);
6616 return hash_64(val, SWEVENT_HLIST_BITS);
6619 static inline struct hlist_head *
6620 __find_swevent_head(struct swevent_hlist *hlist, u64 type, u32 event_id)
6622 u64 hash = swevent_hash(type, event_id);
6624 return &hlist->heads[hash];
6627 /* For the read side: events when they trigger */
6628 static inline struct hlist_head *
6629 find_swevent_head_rcu(struct swevent_htable *swhash, u64 type, u32 event_id)
6631 struct swevent_hlist *hlist;
6633 hlist = rcu_dereference(swhash->swevent_hlist);
6637 return __find_swevent_head(hlist, type, event_id);
6640 /* For the event head insertion and removal in the hlist */
6641 static inline struct hlist_head *
6642 find_swevent_head(struct swevent_htable *swhash, struct perf_event *event)
6644 struct swevent_hlist *hlist;
6645 u32 event_id = event->attr.config;
6646 u64 type = event->attr.type;
6649 * Event scheduling is always serialized against hlist allocation
6650 * and release. Which makes the protected version suitable here.
6651 * The context lock guarantees that.
6653 hlist = rcu_dereference_protected(swhash->swevent_hlist,
6654 lockdep_is_held(&event->ctx->lock));
6658 return __find_swevent_head(hlist, type, event_id);
6661 static void do_perf_sw_event(enum perf_type_id type, u32 event_id,
6663 struct perf_sample_data *data,
6664 struct pt_regs *regs)
6666 struct swevent_htable *swhash = this_cpu_ptr(&swevent_htable);
6667 struct perf_event *event;
6668 struct hlist_head *head;
6671 head = find_swevent_head_rcu(swhash, type, event_id);
6675 hlist_for_each_entry_rcu(event, head, hlist_entry) {
6676 if (perf_swevent_match(event, type, event_id, data, regs))
6677 perf_swevent_event(event, nr, data, regs);
6683 DEFINE_PER_CPU(struct pt_regs, __perf_regs[4]);
6685 int perf_swevent_get_recursion_context(void)
6687 struct swevent_htable *swhash = this_cpu_ptr(&swevent_htable);
6689 return get_recursion_context(swhash->recursion);
6691 EXPORT_SYMBOL_GPL(perf_swevent_get_recursion_context);
6693 inline void perf_swevent_put_recursion_context(int rctx)
6695 struct swevent_htable *swhash = this_cpu_ptr(&swevent_htable);
6697 put_recursion_context(swhash->recursion, rctx);
6700 void ___perf_sw_event(u32 event_id, u64 nr, struct pt_regs *regs, u64 addr)
6702 struct perf_sample_data data;
6704 if (WARN_ON_ONCE(!regs))
6707 perf_sample_data_init(&data, addr, 0);
6708 do_perf_sw_event(PERF_TYPE_SOFTWARE, event_id, nr, &data, regs);
6711 void __perf_sw_event(u32 event_id, u64 nr, struct pt_regs *regs, u64 addr)
6715 preempt_disable_notrace();
6716 rctx = perf_swevent_get_recursion_context();
6717 if (unlikely(rctx < 0))
6720 ___perf_sw_event(event_id, nr, regs, addr);
6722 perf_swevent_put_recursion_context(rctx);
6724 preempt_enable_notrace();
6727 static void perf_swevent_read(struct perf_event *event)
6731 static int perf_swevent_add(struct perf_event *event, int flags)
6733 struct swevent_htable *swhash = this_cpu_ptr(&swevent_htable);
6734 struct hw_perf_event *hwc = &event->hw;
6735 struct hlist_head *head;
6737 if (is_sampling_event(event)) {
6738 hwc->last_period = hwc->sample_period;
6739 perf_swevent_set_period(event);
6742 hwc->state = !(flags & PERF_EF_START);
6744 head = find_swevent_head(swhash, event);
6745 if (WARN_ON_ONCE(!head))
6748 hlist_add_head_rcu(&event->hlist_entry, head);
6749 perf_event_update_userpage(event);
6754 static void perf_swevent_del(struct perf_event *event, int flags)
6756 hlist_del_rcu(&event->hlist_entry);
6759 static void perf_swevent_start(struct perf_event *event, int flags)
6761 event->hw.state = 0;
6764 static void perf_swevent_stop(struct perf_event *event, int flags)
6766 event->hw.state = PERF_HES_STOPPED;
6769 /* Deref the hlist from the update side */
6770 static inline struct swevent_hlist *
6771 swevent_hlist_deref(struct swevent_htable *swhash)
6773 return rcu_dereference_protected(swhash->swevent_hlist,
6774 lockdep_is_held(&swhash->hlist_mutex));
6777 static void swevent_hlist_release(struct swevent_htable *swhash)
6779 struct swevent_hlist *hlist = swevent_hlist_deref(swhash);
6784 RCU_INIT_POINTER(swhash->swevent_hlist, NULL);
6785 kfree_rcu(hlist, rcu_head);
6788 static void swevent_hlist_put_cpu(struct perf_event *event, int cpu)
6790 struct swevent_htable *swhash = &per_cpu(swevent_htable, cpu);
6792 mutex_lock(&swhash->hlist_mutex);
6794 if (!--swhash->hlist_refcount)
6795 swevent_hlist_release(swhash);
6797 mutex_unlock(&swhash->hlist_mutex);
6800 static void swevent_hlist_put(struct perf_event *event)
6804 for_each_possible_cpu(cpu)
6805 swevent_hlist_put_cpu(event, cpu);
6808 static int swevent_hlist_get_cpu(struct perf_event *event, int cpu)
6810 struct swevent_htable *swhash = &per_cpu(swevent_htable, cpu);
6813 mutex_lock(&swhash->hlist_mutex);
6814 if (!swevent_hlist_deref(swhash) && cpu_online(cpu)) {
6815 struct swevent_hlist *hlist;
6817 hlist = kzalloc(sizeof(*hlist), GFP_KERNEL);
6822 rcu_assign_pointer(swhash->swevent_hlist, hlist);
6824 swhash->hlist_refcount++;
6826 mutex_unlock(&swhash->hlist_mutex);
6831 static int swevent_hlist_get(struct perf_event *event)
6834 int cpu, failed_cpu;
6837 for_each_possible_cpu(cpu) {
6838 err = swevent_hlist_get_cpu(event, cpu);
6848 for_each_possible_cpu(cpu) {
6849 if (cpu == failed_cpu)
6851 swevent_hlist_put_cpu(event, cpu);
6858 struct static_key perf_swevent_enabled[PERF_COUNT_SW_MAX];
6860 static void sw_perf_event_destroy(struct perf_event *event)
6862 u64 event_id = event->attr.config;
6864 WARN_ON(event->parent);
6866 static_key_slow_dec(&perf_swevent_enabled[event_id]);
6867 swevent_hlist_put(event);
6870 static int perf_swevent_init(struct perf_event *event)
6872 u64 event_id = event->attr.config;
6874 if (event->attr.type != PERF_TYPE_SOFTWARE)
6878 * no branch sampling for software events
6880 if (has_branch_stack(event))
6884 case PERF_COUNT_SW_CPU_CLOCK:
6885 case PERF_COUNT_SW_TASK_CLOCK:
6892 if (event_id >= PERF_COUNT_SW_MAX)
6895 if (!event->parent) {
6898 err = swevent_hlist_get(event);
6902 static_key_slow_inc(&perf_swevent_enabled[event_id]);
6903 event->destroy = sw_perf_event_destroy;
6909 static struct pmu perf_swevent = {
6910 .task_ctx_nr = perf_sw_context,
6912 .capabilities = PERF_PMU_CAP_NO_NMI,
6914 .event_init = perf_swevent_init,
6915 .add = perf_swevent_add,
6916 .del = perf_swevent_del,
6917 .start = perf_swevent_start,
6918 .stop = perf_swevent_stop,
6919 .read = perf_swevent_read,
6922 #ifdef CONFIG_EVENT_TRACING
6924 static int perf_tp_filter_match(struct perf_event *event,
6925 struct perf_sample_data *data)
6927 void *record = data->raw->data;
6929 /* only top level events have filters set */
6931 event = event->parent;
6933 if (likely(!event->filter) || filter_match_preds(event->filter, record))
6938 static int perf_tp_event_match(struct perf_event *event,
6939 struct perf_sample_data *data,
6940 struct pt_regs *regs)
6942 if (event->hw.state & PERF_HES_STOPPED)
6945 * All tracepoints are from kernel-space.
6947 if (event->attr.exclude_kernel)
6950 if (!perf_tp_filter_match(event, data))
6956 void perf_tp_event(u64 addr, u64 count, void *record, int entry_size,
6957 struct pt_regs *regs, struct hlist_head *head, int rctx,
6958 struct task_struct *task)
6960 struct perf_sample_data data;
6961 struct perf_event *event;
6963 struct perf_raw_record raw = {
6968 perf_sample_data_init(&data, addr, 0);
6971 hlist_for_each_entry_rcu(event, head, hlist_entry) {
6972 if (perf_tp_event_match(event, &data, regs))
6973 perf_swevent_event(event, count, &data, regs);
6977 * If we got specified a target task, also iterate its context and
6978 * deliver this event there too.
6980 if (task && task != current) {
6981 struct perf_event_context *ctx;
6982 struct trace_entry *entry = record;
6985 ctx = rcu_dereference(task->perf_event_ctxp[perf_sw_context]);
6989 list_for_each_entry_rcu(event, &ctx->event_list, event_entry) {
6990 if (event->attr.type != PERF_TYPE_TRACEPOINT)
6992 if (event->attr.config != entry->type)
6994 if (perf_tp_event_match(event, &data, regs))
6995 perf_swevent_event(event, count, &data, regs);
7001 perf_swevent_put_recursion_context(rctx);
7003 EXPORT_SYMBOL_GPL(perf_tp_event);
7005 static void tp_perf_event_destroy(struct perf_event *event)
7007 perf_trace_destroy(event);
7010 static int perf_tp_event_init(struct perf_event *event)
7014 if (event->attr.type != PERF_TYPE_TRACEPOINT)
7018 * no branch sampling for tracepoint events
7020 if (has_branch_stack(event))
7023 err = perf_trace_init(event);
7027 event->destroy = tp_perf_event_destroy;
7032 static struct pmu perf_tracepoint = {
7033 .task_ctx_nr = perf_sw_context,
7035 .event_init = perf_tp_event_init,
7036 .add = perf_trace_add,
7037 .del = perf_trace_del,
7038 .start = perf_swevent_start,
7039 .stop = perf_swevent_stop,
7040 .read = perf_swevent_read,
7043 static inline void perf_tp_register(void)
7045 perf_pmu_register(&perf_tracepoint, "tracepoint", PERF_TYPE_TRACEPOINT);
7048 static int perf_event_set_filter(struct perf_event *event, void __user *arg)
7053 if (event->attr.type != PERF_TYPE_TRACEPOINT)
7056 filter_str = strndup_user(arg, PAGE_SIZE);
7057 if (IS_ERR(filter_str))
7058 return PTR_ERR(filter_str);
7060 ret = ftrace_profile_set_filter(event, event->attr.config, filter_str);
7066 static void perf_event_free_filter(struct perf_event *event)
7068 ftrace_profile_free_filter(event);
7071 static int perf_event_set_bpf_prog(struct perf_event *event, u32 prog_fd)
7073 struct bpf_prog *prog;
7075 if (event->attr.type != PERF_TYPE_TRACEPOINT)
7078 if (event->tp_event->prog)
7081 if (!(event->tp_event->flags & TRACE_EVENT_FL_UKPROBE))
7082 /* bpf programs can only be attached to u/kprobes */
7085 prog = bpf_prog_get(prog_fd);
7087 return PTR_ERR(prog);
7089 if (prog->type != BPF_PROG_TYPE_KPROBE) {
7090 /* valid fd, but invalid bpf program type */
7095 event->tp_event->prog = prog;
7100 static void perf_event_free_bpf_prog(struct perf_event *event)
7102 struct bpf_prog *prog;
7104 if (!event->tp_event)
7107 prog = event->tp_event->prog;
7109 event->tp_event->prog = NULL;
7116 static inline void perf_tp_register(void)
7120 static int perf_event_set_filter(struct perf_event *event, void __user *arg)
7125 static void perf_event_free_filter(struct perf_event *event)
7129 static int perf_event_set_bpf_prog(struct perf_event *event, u32 prog_fd)
7134 static void perf_event_free_bpf_prog(struct perf_event *event)
7137 #endif /* CONFIG_EVENT_TRACING */
7139 #ifdef CONFIG_HAVE_HW_BREAKPOINT
7140 void perf_bp_event(struct perf_event *bp, void *data)
7142 struct perf_sample_data sample;
7143 struct pt_regs *regs = data;
7145 perf_sample_data_init(&sample, bp->attr.bp_addr, 0);
7147 if (!bp->hw.state && !perf_exclude_event(bp, regs))
7148 perf_swevent_event(bp, 1, &sample, regs);
7153 * hrtimer based swevent callback
7156 static enum hrtimer_restart perf_swevent_hrtimer(struct hrtimer *hrtimer)
7158 enum hrtimer_restart ret = HRTIMER_RESTART;
7159 struct perf_sample_data data;
7160 struct pt_regs *regs;
7161 struct perf_event *event;
7164 event = container_of(hrtimer, struct perf_event, hw.hrtimer);
7166 if (event->state != PERF_EVENT_STATE_ACTIVE)
7167 return HRTIMER_NORESTART;
7169 event->pmu->read(event);
7171 perf_sample_data_init(&data, 0, event->hw.last_period);
7172 regs = get_irq_regs();
7174 if (regs && !perf_exclude_event(event, regs)) {
7175 if (!(event->attr.exclude_idle && is_idle_task(current)))
7176 if (__perf_event_overflow(event, 1, &data, regs))
7177 ret = HRTIMER_NORESTART;
7180 period = max_t(u64, 10000, event->hw.sample_period);
7181 hrtimer_forward_now(hrtimer, ns_to_ktime(period));
7186 static void perf_swevent_start_hrtimer(struct perf_event *event)
7188 struct hw_perf_event *hwc = &event->hw;
7191 if (!is_sampling_event(event))
7194 period = local64_read(&hwc->period_left);
7199 local64_set(&hwc->period_left, 0);
7201 period = max_t(u64, 10000, hwc->sample_period);
7203 hrtimer_start(&hwc->hrtimer, ns_to_ktime(period),
7204 HRTIMER_MODE_REL_PINNED);
7207 static void perf_swevent_cancel_hrtimer(struct perf_event *event)
7209 struct hw_perf_event *hwc = &event->hw;
7211 if (is_sampling_event(event)) {
7212 ktime_t remaining = hrtimer_get_remaining(&hwc->hrtimer);
7213 local64_set(&hwc->period_left, ktime_to_ns(remaining));
7215 hrtimer_cancel(&hwc->hrtimer);
7219 static void perf_swevent_init_hrtimer(struct perf_event *event)
7221 struct hw_perf_event *hwc = &event->hw;
7223 if (!is_sampling_event(event))
7226 hrtimer_init(&hwc->hrtimer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
7227 hwc->hrtimer.function = perf_swevent_hrtimer;
7230 * Since hrtimers have a fixed rate, we can do a static freq->period
7231 * mapping and avoid the whole period adjust feedback stuff.
7233 if (event->attr.freq) {
7234 long freq = event->attr.sample_freq;
7236 event->attr.sample_period = NSEC_PER_SEC / freq;
7237 hwc->sample_period = event->attr.sample_period;
7238 local64_set(&hwc->period_left, hwc->sample_period);
7239 hwc->last_period = hwc->sample_period;
7240 event->attr.freq = 0;
7245 * Software event: cpu wall time clock
7248 static void cpu_clock_event_update(struct perf_event *event)
7253 now = local_clock();
7254 prev = local64_xchg(&event->hw.prev_count, now);
7255 local64_add(now - prev, &event->count);
7258 static void cpu_clock_event_start(struct perf_event *event, int flags)
7260 local64_set(&event->hw.prev_count, local_clock());
7261 perf_swevent_start_hrtimer(event);
7264 static void cpu_clock_event_stop(struct perf_event *event, int flags)
7266 perf_swevent_cancel_hrtimer(event);
7267 cpu_clock_event_update(event);
7270 static int cpu_clock_event_add(struct perf_event *event, int flags)
7272 if (flags & PERF_EF_START)
7273 cpu_clock_event_start(event, flags);
7274 perf_event_update_userpage(event);
7279 static void cpu_clock_event_del(struct perf_event *event, int flags)
7281 cpu_clock_event_stop(event, flags);
7284 static void cpu_clock_event_read(struct perf_event *event)
7286 cpu_clock_event_update(event);
7289 static int cpu_clock_event_init(struct perf_event *event)
7291 if (event->attr.type != PERF_TYPE_SOFTWARE)
7294 if (event->attr.config != PERF_COUNT_SW_CPU_CLOCK)
7298 * no branch sampling for software events
7300 if (has_branch_stack(event))
7303 perf_swevent_init_hrtimer(event);
7308 static struct pmu perf_cpu_clock = {
7309 .task_ctx_nr = perf_sw_context,
7311 .capabilities = PERF_PMU_CAP_NO_NMI,
7313 .event_init = cpu_clock_event_init,
7314 .add = cpu_clock_event_add,
7315 .del = cpu_clock_event_del,
7316 .start = cpu_clock_event_start,
7317 .stop = cpu_clock_event_stop,
7318 .read = cpu_clock_event_read,
7322 * Software event: task time clock
7325 static void task_clock_event_update(struct perf_event *event, u64 now)
7330 prev = local64_xchg(&event->hw.prev_count, now);
7332 local64_add(delta, &event->count);
7335 static void task_clock_event_start(struct perf_event *event, int flags)
7337 local64_set(&event->hw.prev_count, event->ctx->time);
7338 perf_swevent_start_hrtimer(event);
7341 static void task_clock_event_stop(struct perf_event *event, int flags)
7343 perf_swevent_cancel_hrtimer(event);
7344 task_clock_event_update(event, event->ctx->time);
7347 static int task_clock_event_add(struct perf_event *event, int flags)
7349 if (flags & PERF_EF_START)
7350 task_clock_event_start(event, flags);
7351 perf_event_update_userpage(event);
7356 static void task_clock_event_del(struct perf_event *event, int flags)
7358 task_clock_event_stop(event, PERF_EF_UPDATE);
7361 static void task_clock_event_read(struct perf_event *event)
7363 u64 now = perf_clock();
7364 u64 delta = now - event->ctx->timestamp;
7365 u64 time = event->ctx->time + delta;
7367 task_clock_event_update(event, time);
7370 static int task_clock_event_init(struct perf_event *event)
7372 if (event->attr.type != PERF_TYPE_SOFTWARE)
7375 if (event->attr.config != PERF_COUNT_SW_TASK_CLOCK)
7379 * no branch sampling for software events
7381 if (has_branch_stack(event))
7384 perf_swevent_init_hrtimer(event);
7389 static struct pmu perf_task_clock = {
7390 .task_ctx_nr = perf_sw_context,
7392 .capabilities = PERF_PMU_CAP_NO_NMI,
7394 .event_init = task_clock_event_init,
7395 .add = task_clock_event_add,
7396 .del = task_clock_event_del,
7397 .start = task_clock_event_start,
7398 .stop = task_clock_event_stop,
7399 .read = task_clock_event_read,
7402 static void perf_pmu_nop_void(struct pmu *pmu)
7406 static void perf_pmu_nop_txn(struct pmu *pmu, unsigned int flags)
7410 static int perf_pmu_nop_int(struct pmu *pmu)
7415 static DEFINE_PER_CPU(unsigned int, nop_txn_flags);
7417 static void perf_pmu_start_txn(struct pmu *pmu, unsigned int flags)
7419 __this_cpu_write(nop_txn_flags, flags);
7421 if (flags & ~PERF_PMU_TXN_ADD)
7424 perf_pmu_disable(pmu);
7427 static int perf_pmu_commit_txn(struct pmu *pmu)
7429 unsigned int flags = __this_cpu_read(nop_txn_flags);
7431 __this_cpu_write(nop_txn_flags, 0);
7433 if (flags & ~PERF_PMU_TXN_ADD)
7436 perf_pmu_enable(pmu);
7440 static void perf_pmu_cancel_txn(struct pmu *pmu)
7442 unsigned int flags = __this_cpu_read(nop_txn_flags);
7444 __this_cpu_write(nop_txn_flags, 0);
7446 if (flags & ~PERF_PMU_TXN_ADD)
7449 perf_pmu_enable(pmu);
7452 static int perf_event_idx_default(struct perf_event *event)
7458 * Ensures all contexts with the same task_ctx_nr have the same
7459 * pmu_cpu_context too.
7461 static struct perf_cpu_context __percpu *find_pmu_context(int ctxn)
7468 list_for_each_entry(pmu, &pmus, entry) {
7469 if (pmu->task_ctx_nr == ctxn)
7470 return pmu->pmu_cpu_context;
7476 static void update_pmu_context(struct pmu *pmu, struct pmu *old_pmu)
7480 for_each_possible_cpu(cpu) {
7481 struct perf_cpu_context *cpuctx;
7483 cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
7485 if (cpuctx->unique_pmu == old_pmu)
7486 cpuctx->unique_pmu = pmu;
7490 static void free_pmu_context(struct pmu *pmu)
7494 mutex_lock(&pmus_lock);
7496 * Like a real lame refcount.
7498 list_for_each_entry(i, &pmus, entry) {
7499 if (i->pmu_cpu_context == pmu->pmu_cpu_context) {
7500 update_pmu_context(i, pmu);
7505 free_percpu(pmu->pmu_cpu_context);
7507 mutex_unlock(&pmus_lock);
7509 static struct idr pmu_idr;
7512 type_show(struct device *dev, struct device_attribute *attr, char *page)
7514 struct pmu *pmu = dev_get_drvdata(dev);
7516 return snprintf(page, PAGE_SIZE-1, "%d\n", pmu->type);
7518 static DEVICE_ATTR_RO(type);
7521 perf_event_mux_interval_ms_show(struct device *dev,
7522 struct device_attribute *attr,
7525 struct pmu *pmu = dev_get_drvdata(dev);
7527 return snprintf(page, PAGE_SIZE-1, "%d\n", pmu->hrtimer_interval_ms);
7530 static DEFINE_MUTEX(mux_interval_mutex);
7533 perf_event_mux_interval_ms_store(struct device *dev,
7534 struct device_attribute *attr,
7535 const char *buf, size_t count)
7537 struct pmu *pmu = dev_get_drvdata(dev);
7538 int timer, cpu, ret;
7540 ret = kstrtoint(buf, 0, &timer);
7547 /* same value, noting to do */
7548 if (timer == pmu->hrtimer_interval_ms)
7551 mutex_lock(&mux_interval_mutex);
7552 pmu->hrtimer_interval_ms = timer;
7554 /* update all cpuctx for this PMU */
7556 for_each_online_cpu(cpu) {
7557 struct perf_cpu_context *cpuctx;
7558 cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
7559 cpuctx->hrtimer_interval = ns_to_ktime(NSEC_PER_MSEC * timer);
7561 cpu_function_call(cpu,
7562 (remote_function_f)perf_mux_hrtimer_restart, cpuctx);
7565 mutex_unlock(&mux_interval_mutex);
7569 static DEVICE_ATTR_RW(perf_event_mux_interval_ms);
7571 static struct attribute *pmu_dev_attrs[] = {
7572 &dev_attr_type.attr,
7573 &dev_attr_perf_event_mux_interval_ms.attr,
7576 ATTRIBUTE_GROUPS(pmu_dev);
7578 static int pmu_bus_running;
7579 static struct bus_type pmu_bus = {
7580 .name = "event_source",
7581 .dev_groups = pmu_dev_groups,
7584 static void pmu_dev_release(struct device *dev)
7589 static int pmu_dev_alloc(struct pmu *pmu)
7593 pmu->dev = kzalloc(sizeof(struct device), GFP_KERNEL);
7597 pmu->dev->groups = pmu->attr_groups;
7598 device_initialize(pmu->dev);
7599 ret = dev_set_name(pmu->dev, "%s", pmu->name);
7603 dev_set_drvdata(pmu->dev, pmu);
7604 pmu->dev->bus = &pmu_bus;
7605 pmu->dev->release = pmu_dev_release;
7606 ret = device_add(pmu->dev);
7614 put_device(pmu->dev);
7618 static struct lock_class_key cpuctx_mutex;
7619 static struct lock_class_key cpuctx_lock;
7621 int perf_pmu_register(struct pmu *pmu, const char *name, int type)
7625 mutex_lock(&pmus_lock);
7627 pmu->pmu_disable_count = alloc_percpu(int);
7628 if (!pmu->pmu_disable_count)
7637 type = idr_alloc(&pmu_idr, pmu, PERF_TYPE_MAX, 0, GFP_KERNEL);
7645 if (pmu_bus_running) {
7646 ret = pmu_dev_alloc(pmu);
7652 pmu->pmu_cpu_context = find_pmu_context(pmu->task_ctx_nr);
7653 if (pmu->pmu_cpu_context)
7654 goto got_cpu_context;
7657 pmu->pmu_cpu_context = alloc_percpu(struct perf_cpu_context);
7658 if (!pmu->pmu_cpu_context)
7661 for_each_possible_cpu(cpu) {
7662 struct perf_cpu_context *cpuctx;
7664 cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
7665 __perf_event_init_context(&cpuctx->ctx);
7666 lockdep_set_class(&cpuctx->ctx.mutex, &cpuctx_mutex);
7667 lockdep_set_class(&cpuctx->ctx.lock, &cpuctx_lock);
7668 cpuctx->ctx.pmu = pmu;
7670 __perf_mux_hrtimer_init(cpuctx, cpu);
7672 cpuctx->unique_pmu = pmu;
7676 if (!pmu->start_txn) {
7677 if (pmu->pmu_enable) {
7679 * If we have pmu_enable/pmu_disable calls, install
7680 * transaction stubs that use that to try and batch
7681 * hardware accesses.
7683 pmu->start_txn = perf_pmu_start_txn;
7684 pmu->commit_txn = perf_pmu_commit_txn;
7685 pmu->cancel_txn = perf_pmu_cancel_txn;
7687 pmu->start_txn = perf_pmu_nop_txn;
7688 pmu->commit_txn = perf_pmu_nop_int;
7689 pmu->cancel_txn = perf_pmu_nop_void;
7693 if (!pmu->pmu_enable) {
7694 pmu->pmu_enable = perf_pmu_nop_void;
7695 pmu->pmu_disable = perf_pmu_nop_void;
7698 if (!pmu->event_idx)
7699 pmu->event_idx = perf_event_idx_default;
7701 list_add_rcu(&pmu->entry, &pmus);
7702 atomic_set(&pmu->exclusive_cnt, 0);
7705 mutex_unlock(&pmus_lock);
7710 device_del(pmu->dev);
7711 put_device(pmu->dev);
7714 if (pmu->type >= PERF_TYPE_MAX)
7715 idr_remove(&pmu_idr, pmu->type);
7718 free_percpu(pmu->pmu_disable_count);
7721 EXPORT_SYMBOL_GPL(perf_pmu_register);
7723 void perf_pmu_unregister(struct pmu *pmu)
7725 mutex_lock(&pmus_lock);
7726 list_del_rcu(&pmu->entry);
7727 mutex_unlock(&pmus_lock);
7730 * We dereference the pmu list under both SRCU and regular RCU, so
7731 * synchronize against both of those.
7733 synchronize_srcu(&pmus_srcu);
7736 free_percpu(pmu->pmu_disable_count);
7737 if (pmu->type >= PERF_TYPE_MAX)
7738 idr_remove(&pmu_idr, pmu->type);
7739 device_del(pmu->dev);
7740 put_device(pmu->dev);
7741 free_pmu_context(pmu);
7743 EXPORT_SYMBOL_GPL(perf_pmu_unregister);
7745 static int perf_try_init_event(struct pmu *pmu, struct perf_event *event)
7747 struct perf_event_context *ctx = NULL;
7750 if (!try_module_get(pmu->module))
7753 if (event->group_leader != event) {
7755 * This ctx->mutex can nest when we're called through
7756 * inheritance. See the perf_event_ctx_lock_nested() comment.
7758 ctx = perf_event_ctx_lock_nested(event->group_leader,
7759 SINGLE_DEPTH_NESTING);
7764 ret = pmu->event_init(event);
7767 perf_event_ctx_unlock(event->group_leader, ctx);
7770 module_put(pmu->module);
7775 static struct pmu *perf_init_event(struct perf_event *event)
7777 struct pmu *pmu = NULL;
7781 idx = srcu_read_lock(&pmus_srcu);
7784 pmu = idr_find(&pmu_idr, event->attr.type);
7787 ret = perf_try_init_event(pmu, event);
7793 list_for_each_entry_rcu(pmu, &pmus, entry) {
7794 ret = perf_try_init_event(pmu, event);
7798 if (ret != -ENOENT) {
7803 pmu = ERR_PTR(-ENOENT);
7805 srcu_read_unlock(&pmus_srcu, idx);
7810 static void account_event_cpu(struct perf_event *event, int cpu)
7815 if (is_cgroup_event(event))
7816 atomic_inc(&per_cpu(perf_cgroup_events, cpu));
7819 static void account_event(struct perf_event *event)
7826 if (event->attach_state & PERF_ATTACH_TASK)
7828 if (event->attr.mmap || event->attr.mmap_data)
7829 atomic_inc(&nr_mmap_events);
7830 if (event->attr.comm)
7831 atomic_inc(&nr_comm_events);
7832 if (event->attr.task)
7833 atomic_inc(&nr_task_events);
7834 if (event->attr.freq) {
7835 if (atomic_inc_return(&nr_freq_events) == 1)
7836 tick_nohz_full_kick_all();
7838 if (event->attr.context_switch) {
7839 atomic_inc(&nr_switch_events);
7842 if (has_branch_stack(event))
7844 if (is_cgroup_event(event))
7848 if (atomic_inc_not_zero(&perf_sched_count))
7851 mutex_lock(&perf_sched_mutex);
7852 if (!atomic_read(&perf_sched_count)) {
7853 static_branch_enable(&perf_sched_events);
7855 * Guarantee that all CPUs observe they key change and
7856 * call the perf scheduling hooks before proceeding to
7857 * install events that need them.
7859 synchronize_sched();
7862 * Now that we have waited for the sync_sched(), allow further
7863 * increments to by-pass the mutex.
7865 atomic_inc(&perf_sched_count);
7866 mutex_unlock(&perf_sched_mutex);
7870 account_event_cpu(event, event->cpu);
7874 * Allocate and initialize a event structure
7876 static struct perf_event *
7877 perf_event_alloc(struct perf_event_attr *attr, int cpu,
7878 struct task_struct *task,
7879 struct perf_event *group_leader,
7880 struct perf_event *parent_event,
7881 perf_overflow_handler_t overflow_handler,
7882 void *context, int cgroup_fd)
7885 struct perf_event *event;
7886 struct hw_perf_event *hwc;
7889 if ((unsigned)cpu >= nr_cpu_ids) {
7890 if (!task || cpu != -1)
7891 return ERR_PTR(-EINVAL);
7894 event = kzalloc(sizeof(*event), GFP_KERNEL);
7896 return ERR_PTR(-ENOMEM);
7899 * Single events are their own group leaders, with an
7900 * empty sibling list:
7903 group_leader = event;
7905 mutex_init(&event->child_mutex);
7906 INIT_LIST_HEAD(&event->child_list);
7908 INIT_LIST_HEAD(&event->group_entry);
7909 INIT_LIST_HEAD(&event->event_entry);
7910 INIT_LIST_HEAD(&event->sibling_list);
7911 INIT_LIST_HEAD(&event->rb_entry);
7912 INIT_LIST_HEAD(&event->active_entry);
7913 INIT_HLIST_NODE(&event->hlist_entry);
7916 init_waitqueue_head(&event->waitq);
7917 init_irq_work(&event->pending, perf_pending_event);
7919 mutex_init(&event->mmap_mutex);
7921 atomic_long_set(&event->refcount, 1);
7923 event->attr = *attr;
7924 event->group_leader = group_leader;
7928 event->parent = parent_event;
7930 event->ns = get_pid_ns(task_active_pid_ns(current));
7931 event->id = atomic64_inc_return(&perf_event_id);
7933 event->state = PERF_EVENT_STATE_INACTIVE;
7936 event->attach_state = PERF_ATTACH_TASK;
7938 * XXX pmu::event_init needs to know what task to account to
7939 * and we cannot use the ctx information because we need the
7940 * pmu before we get a ctx.
7942 event->hw.target = task;
7945 event->clock = &local_clock;
7947 event->clock = parent_event->clock;
7949 if (!overflow_handler && parent_event) {
7950 overflow_handler = parent_event->overflow_handler;
7951 context = parent_event->overflow_handler_context;
7954 event->overflow_handler = overflow_handler;
7955 event->overflow_handler_context = context;
7957 perf_event__state_init(event);
7962 hwc->sample_period = attr->sample_period;
7963 if (attr->freq && attr->sample_freq)
7964 hwc->sample_period = 1;
7965 hwc->last_period = hwc->sample_period;
7967 local64_set(&hwc->period_left, hwc->sample_period);
7970 * we currently do not support PERF_FORMAT_GROUP on inherited events
7972 if (attr->inherit && (attr->read_format & PERF_FORMAT_GROUP))
7975 if (!has_branch_stack(event))
7976 event->attr.branch_sample_type = 0;
7978 if (cgroup_fd != -1) {
7979 err = perf_cgroup_connect(cgroup_fd, event, attr, group_leader);
7984 pmu = perf_init_event(event);
7987 else if (IS_ERR(pmu)) {
7992 err = exclusive_event_init(event);
7996 if (!event->parent) {
7997 if (event->attr.sample_type & PERF_SAMPLE_CALLCHAIN) {
7998 err = get_callchain_buffers();
8007 exclusive_event_destroy(event);
8011 event->destroy(event);
8012 module_put(pmu->module);
8014 if (is_cgroup_event(event))
8015 perf_detach_cgroup(event);
8017 put_pid_ns(event->ns);
8020 return ERR_PTR(err);
8023 static int perf_copy_attr(struct perf_event_attr __user *uattr,
8024 struct perf_event_attr *attr)
8029 if (!access_ok(VERIFY_WRITE, uattr, PERF_ATTR_SIZE_VER0))
8033 * zero the full structure, so that a short copy will be nice.
8035 memset(attr, 0, sizeof(*attr));
8037 ret = get_user(size, &uattr->size);
8041 if (size > PAGE_SIZE) /* silly large */
8044 if (!size) /* abi compat */
8045 size = PERF_ATTR_SIZE_VER0;
8047 if (size < PERF_ATTR_SIZE_VER0)
8051 * If we're handed a bigger struct than we know of,
8052 * ensure all the unknown bits are 0 - i.e. new
8053 * user-space does not rely on any kernel feature
8054 * extensions we dont know about yet.
8056 if (size > sizeof(*attr)) {
8057 unsigned char __user *addr;
8058 unsigned char __user *end;
8061 addr = (void __user *)uattr + sizeof(*attr);
8062 end = (void __user *)uattr + size;
8064 for (; addr < end; addr++) {
8065 ret = get_user(val, addr);
8071 size = sizeof(*attr);
8074 ret = copy_from_user(attr, uattr, size);
8078 if (attr->__reserved_1)
8081 if (attr->sample_type & ~(PERF_SAMPLE_MAX-1))
8084 if (attr->read_format & ~(PERF_FORMAT_MAX-1))
8087 if (attr->sample_type & PERF_SAMPLE_BRANCH_STACK) {
8088 u64 mask = attr->branch_sample_type;
8090 /* only using defined bits */
8091 if (mask & ~(PERF_SAMPLE_BRANCH_MAX-1))
8094 /* at least one branch bit must be set */
8095 if (!(mask & ~PERF_SAMPLE_BRANCH_PLM_ALL))
8098 /* propagate priv level, when not set for branch */
8099 if (!(mask & PERF_SAMPLE_BRANCH_PLM_ALL)) {
8101 /* exclude_kernel checked on syscall entry */
8102 if (!attr->exclude_kernel)
8103 mask |= PERF_SAMPLE_BRANCH_KERNEL;
8105 if (!attr->exclude_user)
8106 mask |= PERF_SAMPLE_BRANCH_USER;
8108 if (!attr->exclude_hv)
8109 mask |= PERF_SAMPLE_BRANCH_HV;
8111 * adjust user setting (for HW filter setup)
8113 attr->branch_sample_type = mask;
8115 /* privileged levels capture (kernel, hv): check permissions */
8116 if ((mask & PERF_SAMPLE_BRANCH_PERM_PLM)
8117 && perf_paranoid_kernel() && !capable(CAP_SYS_ADMIN))
8121 if (attr->sample_type & PERF_SAMPLE_REGS_USER) {
8122 ret = perf_reg_validate(attr->sample_regs_user);
8127 if (attr->sample_type & PERF_SAMPLE_STACK_USER) {
8128 if (!arch_perf_have_user_stack_dump())
8132 * We have __u32 type for the size, but so far
8133 * we can only use __u16 as maximum due to the
8134 * __u16 sample size limit.
8136 if (attr->sample_stack_user >= USHRT_MAX)
8138 else if (!IS_ALIGNED(attr->sample_stack_user, sizeof(u64)))
8142 if (attr->sample_type & PERF_SAMPLE_REGS_INTR)
8143 ret = perf_reg_validate(attr->sample_regs_intr);
8148 put_user(sizeof(*attr), &uattr->size);
8154 perf_event_set_output(struct perf_event *event, struct perf_event *output_event)
8156 struct ring_buffer *rb = NULL;
8162 /* don't allow circular references */
8163 if (event == output_event)
8167 * Don't allow cross-cpu buffers
8169 if (output_event->cpu != event->cpu)
8173 * If its not a per-cpu rb, it must be the same task.
8175 if (output_event->cpu == -1 && output_event->ctx != event->ctx)
8179 * Mixing clocks in the same buffer is trouble you don't need.
8181 if (output_event->clock != event->clock)
8185 * If both events generate aux data, they must be on the same PMU
8187 if (has_aux(event) && has_aux(output_event) &&
8188 event->pmu != output_event->pmu)
8192 mutex_lock(&event->mmap_mutex);
8193 /* Can't redirect output if we've got an active mmap() */
8194 if (atomic_read(&event->mmap_count))
8198 /* get the rb we want to redirect to */
8199 rb = ring_buffer_get(output_event);
8204 ring_buffer_attach(event, rb);
8208 mutex_unlock(&event->mmap_mutex);
8214 static void mutex_lock_double(struct mutex *a, struct mutex *b)
8220 mutex_lock_nested(b, SINGLE_DEPTH_NESTING);
8223 static int perf_event_set_clock(struct perf_event *event, clockid_t clk_id)
8225 bool nmi_safe = false;
8228 case CLOCK_MONOTONIC:
8229 event->clock = &ktime_get_mono_fast_ns;
8233 case CLOCK_MONOTONIC_RAW:
8234 event->clock = &ktime_get_raw_fast_ns;
8238 case CLOCK_REALTIME:
8239 event->clock = &ktime_get_real_ns;
8242 case CLOCK_BOOTTIME:
8243 event->clock = &ktime_get_boot_ns;
8247 event->clock = &ktime_get_tai_ns;
8254 if (!nmi_safe && !(event->pmu->capabilities & PERF_PMU_CAP_NO_NMI))
8261 * sys_perf_event_open - open a performance event, associate it to a task/cpu
8263 * @attr_uptr: event_id type attributes for monitoring/sampling
8266 * @group_fd: group leader event fd
8268 SYSCALL_DEFINE5(perf_event_open,
8269 struct perf_event_attr __user *, attr_uptr,
8270 pid_t, pid, int, cpu, int, group_fd, unsigned long, flags)
8272 struct perf_event *group_leader = NULL, *output_event = NULL;
8273 struct perf_event *event, *sibling;
8274 struct perf_event_attr attr;
8275 struct perf_event_context *ctx, *uninitialized_var(gctx);
8276 struct file *event_file = NULL;
8277 struct fd group = {NULL, 0};
8278 struct task_struct *task = NULL;
8283 int f_flags = O_RDWR;
8286 /* for future expandability... */
8287 if (flags & ~PERF_FLAG_ALL)
8290 err = perf_copy_attr(attr_uptr, &attr);
8294 if (!attr.exclude_kernel) {
8295 if (perf_paranoid_kernel() && !capable(CAP_SYS_ADMIN))
8300 if (attr.sample_freq > sysctl_perf_event_sample_rate)
8303 if (attr.sample_period & (1ULL << 63))
8308 * In cgroup mode, the pid argument is used to pass the fd
8309 * opened to the cgroup directory in cgroupfs. The cpu argument
8310 * designates the cpu on which to monitor threads from that
8313 if ((flags & PERF_FLAG_PID_CGROUP) && (pid == -1 || cpu == -1))
8316 if (flags & PERF_FLAG_FD_CLOEXEC)
8317 f_flags |= O_CLOEXEC;
8319 event_fd = get_unused_fd_flags(f_flags);
8323 if (group_fd != -1) {
8324 err = perf_fget_light(group_fd, &group);
8327 group_leader = group.file->private_data;
8328 if (flags & PERF_FLAG_FD_OUTPUT)
8329 output_event = group_leader;
8330 if (flags & PERF_FLAG_FD_NO_GROUP)
8331 group_leader = NULL;
8334 if (pid != -1 && !(flags & PERF_FLAG_PID_CGROUP)) {
8335 task = find_lively_task_by_vpid(pid);
8337 err = PTR_ERR(task);
8342 if (task && group_leader &&
8343 group_leader->attr.inherit != attr.inherit) {
8350 if (flags & PERF_FLAG_PID_CGROUP)
8353 event = perf_event_alloc(&attr, cpu, task, group_leader, NULL,
8354 NULL, NULL, cgroup_fd);
8355 if (IS_ERR(event)) {
8356 err = PTR_ERR(event);
8360 if (is_sampling_event(event)) {
8361 if (event->pmu->capabilities & PERF_PMU_CAP_NO_INTERRUPT) {
8367 account_event(event);
8370 * Special case software events and allow them to be part of
8371 * any hardware group.
8375 if (attr.use_clockid) {
8376 err = perf_event_set_clock(event, attr.clockid);
8382 (is_software_event(event) != is_software_event(group_leader))) {
8383 if (is_software_event(event)) {
8385 * If event and group_leader are not both a software
8386 * event, and event is, then group leader is not.
8388 * Allow the addition of software events to !software
8389 * groups, this is safe because software events never
8392 pmu = group_leader->pmu;
8393 } else if (is_software_event(group_leader) &&
8394 (group_leader->group_flags & PERF_GROUP_SOFTWARE)) {
8396 * In case the group is a pure software group, and we
8397 * try to add a hardware event, move the whole group to
8398 * the hardware context.
8405 * Get the target context (task or percpu):
8407 ctx = find_get_context(pmu, task, event);
8413 if ((pmu->capabilities & PERF_PMU_CAP_EXCLUSIVE) && group_leader) {
8419 put_task_struct(task);
8424 * Look up the group leader (we will attach this event to it):
8430 * Do not allow a recursive hierarchy (this new sibling
8431 * becoming part of another group-sibling):
8433 if (group_leader->group_leader != group_leader)
8436 /* All events in a group should have the same clock */
8437 if (group_leader->clock != event->clock)
8441 * Do not allow to attach to a group in a different
8442 * task or CPU context:
8446 * Make sure we're both on the same task, or both
8449 if (group_leader->ctx->task != ctx->task)
8453 * Make sure we're both events for the same CPU;
8454 * grouping events for different CPUs is broken; since
8455 * you can never concurrently schedule them anyhow.
8457 if (group_leader->cpu != event->cpu)
8460 if (group_leader->ctx != ctx)
8465 * Only a group leader can be exclusive or pinned
8467 if (attr.exclusive || attr.pinned)
8472 err = perf_event_set_output(event, output_event);
8477 event_file = anon_inode_getfile("[perf_event]", &perf_fops, event,
8479 if (IS_ERR(event_file)) {
8480 err = PTR_ERR(event_file);
8485 gctx = group_leader->ctx;
8486 mutex_lock_double(&gctx->mutex, &ctx->mutex);
8487 if (gctx->task == TASK_TOMBSTONE) {
8492 mutex_lock(&ctx->mutex);
8495 if (ctx->task == TASK_TOMBSTONE) {
8500 if (!perf_event_validate_size(event)) {
8506 * Must be under the same ctx::mutex as perf_install_in_context(),
8507 * because we need to serialize with concurrent event creation.
8509 if (!exclusive_event_installable(event, ctx)) {
8510 /* exclusive and group stuff are assumed mutually exclusive */
8511 WARN_ON_ONCE(move_group);
8517 WARN_ON_ONCE(ctx->parent_ctx);
8521 * See perf_event_ctx_lock() for comments on the details
8522 * of swizzling perf_event::ctx.
8524 perf_remove_from_context(group_leader, 0);
8526 list_for_each_entry(sibling, &group_leader->sibling_list,
8528 perf_remove_from_context(sibling, 0);
8533 * Wait for everybody to stop referencing the events through
8534 * the old lists, before installing it on new lists.
8539 * Install the group siblings before the group leader.
8541 * Because a group leader will try and install the entire group
8542 * (through the sibling list, which is still in-tact), we can
8543 * end up with siblings installed in the wrong context.
8545 * By installing siblings first we NO-OP because they're not
8546 * reachable through the group lists.
8548 list_for_each_entry(sibling, &group_leader->sibling_list,
8550 perf_event__state_init(sibling);
8551 perf_install_in_context(ctx, sibling, sibling->cpu);
8556 * Removing from the context ends up with disabled
8557 * event. What we want here is event in the initial
8558 * startup state, ready to be add into new context.
8560 perf_event__state_init(group_leader);
8561 perf_install_in_context(ctx, group_leader, group_leader->cpu);
8565 * Now that all events are installed in @ctx, nothing
8566 * references @gctx anymore, so drop the last reference we have
8573 * Precalculate sample_data sizes; do while holding ctx::mutex such
8574 * that we're serialized against further additions and before
8575 * perf_install_in_context() which is the point the event is active and
8576 * can use these values.
8578 perf_event__header_size(event);
8579 perf_event__id_header_size(event);
8581 event->owner = current;
8583 perf_install_in_context(ctx, event, event->cpu);
8584 perf_unpin_context(ctx);
8587 mutex_unlock(&gctx->mutex);
8588 mutex_unlock(&ctx->mutex);
8592 mutex_lock(¤t->perf_event_mutex);
8593 list_add_tail(&event->owner_entry, ¤t->perf_event_list);
8594 mutex_unlock(¤t->perf_event_mutex);
8597 * Drop the reference on the group_event after placing the
8598 * new event on the sibling_list. This ensures destruction
8599 * of the group leader will find the pointer to itself in
8600 * perf_group_detach().
8603 fd_install(event_fd, event_file);
8608 mutex_unlock(&gctx->mutex);
8609 mutex_unlock(&ctx->mutex);
8613 perf_unpin_context(ctx);
8617 * If event_file is set, the fput() above will have called ->release()
8618 * and that will take care of freeing the event.
8626 put_task_struct(task);
8630 put_unused_fd(event_fd);
8635 * perf_event_create_kernel_counter
8637 * @attr: attributes of the counter to create
8638 * @cpu: cpu in which the counter is bound
8639 * @task: task to profile (NULL for percpu)
8642 perf_event_create_kernel_counter(struct perf_event_attr *attr, int cpu,
8643 struct task_struct *task,
8644 perf_overflow_handler_t overflow_handler,
8647 struct perf_event_context *ctx;
8648 struct perf_event *event;
8652 * Get the target context (task or percpu):
8655 event = perf_event_alloc(attr, cpu, task, NULL, NULL,
8656 overflow_handler, context, -1);
8657 if (IS_ERR(event)) {
8658 err = PTR_ERR(event);
8662 /* Mark owner so we could distinguish it from user events. */
8663 event->owner = TASK_TOMBSTONE;
8665 account_event(event);
8667 ctx = find_get_context(event->pmu, task, event);
8673 WARN_ON_ONCE(ctx->parent_ctx);
8674 mutex_lock(&ctx->mutex);
8675 if (ctx->task == TASK_TOMBSTONE) {
8680 if (!exclusive_event_installable(event, ctx)) {
8685 perf_install_in_context(ctx, event, cpu);
8686 perf_unpin_context(ctx);
8687 mutex_unlock(&ctx->mutex);
8692 mutex_unlock(&ctx->mutex);
8693 perf_unpin_context(ctx);
8698 return ERR_PTR(err);
8700 EXPORT_SYMBOL_GPL(perf_event_create_kernel_counter);
8702 void perf_pmu_migrate_context(struct pmu *pmu, int src_cpu, int dst_cpu)
8704 struct perf_event_context *src_ctx;
8705 struct perf_event_context *dst_ctx;
8706 struct perf_event *event, *tmp;
8709 src_ctx = &per_cpu_ptr(pmu->pmu_cpu_context, src_cpu)->ctx;
8710 dst_ctx = &per_cpu_ptr(pmu->pmu_cpu_context, dst_cpu)->ctx;
8713 * See perf_event_ctx_lock() for comments on the details
8714 * of swizzling perf_event::ctx.
8716 mutex_lock_double(&src_ctx->mutex, &dst_ctx->mutex);
8717 list_for_each_entry_safe(event, tmp, &src_ctx->event_list,
8719 perf_remove_from_context(event, 0);
8720 unaccount_event_cpu(event, src_cpu);
8722 list_add(&event->migrate_entry, &events);
8726 * Wait for the events to quiesce before re-instating them.
8731 * Re-instate events in 2 passes.
8733 * Skip over group leaders and only install siblings on this first
8734 * pass, siblings will not get enabled without a leader, however a
8735 * leader will enable its siblings, even if those are still on the old
8738 list_for_each_entry_safe(event, tmp, &events, migrate_entry) {
8739 if (event->group_leader == event)
8742 list_del(&event->migrate_entry);
8743 if (event->state >= PERF_EVENT_STATE_OFF)
8744 event->state = PERF_EVENT_STATE_INACTIVE;
8745 account_event_cpu(event, dst_cpu);
8746 perf_install_in_context(dst_ctx, event, dst_cpu);
8751 * Once all the siblings are setup properly, install the group leaders
8754 list_for_each_entry_safe(event, tmp, &events, migrate_entry) {
8755 list_del(&event->migrate_entry);
8756 if (event->state >= PERF_EVENT_STATE_OFF)
8757 event->state = PERF_EVENT_STATE_INACTIVE;
8758 account_event_cpu(event, dst_cpu);
8759 perf_install_in_context(dst_ctx, event, dst_cpu);
8762 mutex_unlock(&dst_ctx->mutex);
8763 mutex_unlock(&src_ctx->mutex);
8765 EXPORT_SYMBOL_GPL(perf_pmu_migrate_context);
8767 static void sync_child_event(struct perf_event *child_event,
8768 struct task_struct *child)
8770 struct perf_event *parent_event = child_event->parent;
8773 if (child_event->attr.inherit_stat)
8774 perf_event_read_event(child_event, child);
8776 child_val = perf_event_count(child_event);
8779 * Add back the child's count to the parent's count:
8781 atomic64_add(child_val, &parent_event->child_count);
8782 atomic64_add(child_event->total_time_enabled,
8783 &parent_event->child_total_time_enabled);
8784 atomic64_add(child_event->total_time_running,
8785 &parent_event->child_total_time_running);
8789 perf_event_exit_event(struct perf_event *child_event,
8790 struct perf_event_context *child_ctx,
8791 struct task_struct *child)
8793 struct perf_event *parent_event = child_event->parent;
8796 * Do not destroy the 'original' grouping; because of the context
8797 * switch optimization the original events could've ended up in a
8798 * random child task.
8800 * If we were to destroy the original group, all group related
8801 * operations would cease to function properly after this random
8804 * Do destroy all inherited groups, we don't care about those
8805 * and being thorough is better.
8807 raw_spin_lock_irq(&child_ctx->lock);
8808 WARN_ON_ONCE(child_ctx->is_active);
8811 perf_group_detach(child_event);
8812 list_del_event(child_event, child_ctx);
8813 child_event->state = PERF_EVENT_STATE_EXIT; /* is_event_hup() */
8814 raw_spin_unlock_irq(&child_ctx->lock);
8817 * Parent events are governed by their filedesc, retain them.
8819 if (!parent_event) {
8820 perf_event_wakeup(child_event);
8824 * Child events can be cleaned up.
8827 sync_child_event(child_event, child);
8830 * Remove this event from the parent's list
8832 WARN_ON_ONCE(parent_event->ctx->parent_ctx);
8833 mutex_lock(&parent_event->child_mutex);
8834 list_del_init(&child_event->child_list);
8835 mutex_unlock(&parent_event->child_mutex);
8838 * Kick perf_poll() for is_event_hup().
8840 perf_event_wakeup(parent_event);
8841 free_event(child_event);
8842 put_event(parent_event);
8845 static void perf_event_exit_task_context(struct task_struct *child, int ctxn)
8847 struct perf_event_context *child_ctx, *clone_ctx = NULL;
8848 struct perf_event *child_event, *next;
8850 WARN_ON_ONCE(child != current);
8852 child_ctx = perf_pin_task_context(child, ctxn);
8857 * In order to reduce the amount of tricky in ctx tear-down, we hold
8858 * ctx::mutex over the entire thing. This serializes against almost
8859 * everything that wants to access the ctx.
8861 * The exception is sys_perf_event_open() /
8862 * perf_event_create_kernel_count() which does find_get_context()
8863 * without ctx::mutex (it cannot because of the move_group double mutex
8864 * lock thing). See the comments in perf_install_in_context().
8866 mutex_lock(&child_ctx->mutex);
8869 * In a single ctx::lock section, de-schedule the events and detach the
8870 * context from the task such that we cannot ever get it scheduled back
8873 raw_spin_lock_irq(&child_ctx->lock);
8874 task_ctx_sched_out(__get_cpu_context(child_ctx), child_ctx);
8877 * Now that the context is inactive, destroy the task <-> ctx relation
8878 * and mark the context dead.
8880 RCU_INIT_POINTER(child->perf_event_ctxp[ctxn], NULL);
8881 put_ctx(child_ctx); /* cannot be last */
8882 WRITE_ONCE(child_ctx->task, TASK_TOMBSTONE);
8883 put_task_struct(current); /* cannot be last */
8885 clone_ctx = unclone_ctx(child_ctx);
8886 raw_spin_unlock_irq(&child_ctx->lock);
8892 * Report the task dead after unscheduling the events so that we
8893 * won't get any samples after PERF_RECORD_EXIT. We can however still
8894 * get a few PERF_RECORD_READ events.
8896 perf_event_task(child, child_ctx, 0);
8898 list_for_each_entry_safe(child_event, next, &child_ctx->event_list, event_entry)
8899 perf_event_exit_event(child_event, child_ctx, child);
8901 mutex_unlock(&child_ctx->mutex);
8907 * When a child task exits, feed back event values to parent events.
8909 void perf_event_exit_task(struct task_struct *child)
8911 struct perf_event *event, *tmp;
8914 mutex_lock(&child->perf_event_mutex);
8915 list_for_each_entry_safe(event, tmp, &child->perf_event_list,
8917 list_del_init(&event->owner_entry);
8920 * Ensure the list deletion is visible before we clear
8921 * the owner, closes a race against perf_release() where
8922 * we need to serialize on the owner->perf_event_mutex.
8924 smp_store_release(&event->owner, NULL);
8926 mutex_unlock(&child->perf_event_mutex);
8928 for_each_task_context_nr(ctxn)
8929 perf_event_exit_task_context(child, ctxn);
8932 * The perf_event_exit_task_context calls perf_event_task
8933 * with child's task_ctx, which generates EXIT events for
8934 * child contexts and sets child->perf_event_ctxp[] to NULL.
8935 * At this point we need to send EXIT events to cpu contexts.
8937 perf_event_task(child, NULL, 0);
8940 static void perf_free_event(struct perf_event *event,
8941 struct perf_event_context *ctx)
8943 struct perf_event *parent = event->parent;
8945 if (WARN_ON_ONCE(!parent))
8948 mutex_lock(&parent->child_mutex);
8949 list_del_init(&event->child_list);
8950 mutex_unlock(&parent->child_mutex);
8954 raw_spin_lock_irq(&ctx->lock);
8955 perf_group_detach(event);
8956 list_del_event(event, ctx);
8957 raw_spin_unlock_irq(&ctx->lock);
8962 * Free an unexposed, unused context as created by inheritance by
8963 * perf_event_init_task below, used by fork() in case of fail.
8965 * Not all locks are strictly required, but take them anyway to be nice and
8966 * help out with the lockdep assertions.
8968 void perf_event_free_task(struct task_struct *task)
8970 struct perf_event_context *ctx;
8971 struct perf_event *event, *tmp;
8974 for_each_task_context_nr(ctxn) {
8975 ctx = task->perf_event_ctxp[ctxn];
8979 mutex_lock(&ctx->mutex);
8981 list_for_each_entry_safe(event, tmp, &ctx->pinned_groups,
8983 perf_free_event(event, ctx);
8985 list_for_each_entry_safe(event, tmp, &ctx->flexible_groups,
8987 perf_free_event(event, ctx);
8989 if (!list_empty(&ctx->pinned_groups) ||
8990 !list_empty(&ctx->flexible_groups))
8993 mutex_unlock(&ctx->mutex);
8999 void perf_event_delayed_put(struct task_struct *task)
9003 for_each_task_context_nr(ctxn)
9004 WARN_ON_ONCE(task->perf_event_ctxp[ctxn]);
9007 struct file *perf_event_get(unsigned int fd)
9011 file = fget_raw(fd);
9013 return ERR_PTR(-EBADF);
9015 if (file->f_op != &perf_fops) {
9017 return ERR_PTR(-EBADF);
9023 const struct perf_event_attr *perf_event_attrs(struct perf_event *event)
9026 return ERR_PTR(-EINVAL);
9028 return &event->attr;
9032 * inherit a event from parent task to child task:
9034 static struct perf_event *
9035 inherit_event(struct perf_event *parent_event,
9036 struct task_struct *parent,
9037 struct perf_event_context *parent_ctx,
9038 struct task_struct *child,
9039 struct perf_event *group_leader,
9040 struct perf_event_context *child_ctx)
9042 enum perf_event_active_state parent_state = parent_event->state;
9043 struct perf_event *child_event;
9044 unsigned long flags;
9047 * Instead of creating recursive hierarchies of events,
9048 * we link inherited events back to the original parent,
9049 * which has a filp for sure, which we use as the reference
9052 if (parent_event->parent)
9053 parent_event = parent_event->parent;
9055 child_event = perf_event_alloc(&parent_event->attr,
9058 group_leader, parent_event,
9060 if (IS_ERR(child_event))
9064 * is_orphaned_event() and list_add_tail(&parent_event->child_list)
9065 * must be under the same lock in order to serialize against
9066 * perf_event_release_kernel(), such that either we must observe
9067 * is_orphaned_event() or they will observe us on the child_list.
9069 mutex_lock(&parent_event->child_mutex);
9070 if (is_orphaned_event(parent_event) ||
9071 !atomic_long_inc_not_zero(&parent_event->refcount)) {
9072 mutex_unlock(&parent_event->child_mutex);
9073 free_event(child_event);
9080 * Make the child state follow the state of the parent event,
9081 * not its attr.disabled bit. We hold the parent's mutex,
9082 * so we won't race with perf_event_{en, dis}able_family.
9084 if (parent_state >= PERF_EVENT_STATE_INACTIVE)
9085 child_event->state = PERF_EVENT_STATE_INACTIVE;
9087 child_event->state = PERF_EVENT_STATE_OFF;
9089 if (parent_event->attr.freq) {
9090 u64 sample_period = parent_event->hw.sample_period;
9091 struct hw_perf_event *hwc = &child_event->hw;
9093 hwc->sample_period = sample_period;
9094 hwc->last_period = sample_period;
9096 local64_set(&hwc->period_left, sample_period);
9099 child_event->ctx = child_ctx;
9100 child_event->overflow_handler = parent_event->overflow_handler;
9101 child_event->overflow_handler_context
9102 = parent_event->overflow_handler_context;
9105 * Precalculate sample_data sizes
9107 perf_event__header_size(child_event);
9108 perf_event__id_header_size(child_event);
9111 * Link it up in the child's context:
9113 raw_spin_lock_irqsave(&child_ctx->lock, flags);
9114 add_event_to_ctx(child_event, child_ctx);
9115 raw_spin_unlock_irqrestore(&child_ctx->lock, flags);
9118 * Link this into the parent event's child list
9120 list_add_tail(&child_event->child_list, &parent_event->child_list);
9121 mutex_unlock(&parent_event->child_mutex);
9126 static int inherit_group(struct perf_event *parent_event,
9127 struct task_struct *parent,
9128 struct perf_event_context *parent_ctx,
9129 struct task_struct *child,
9130 struct perf_event_context *child_ctx)
9132 struct perf_event *leader;
9133 struct perf_event *sub;
9134 struct perf_event *child_ctr;
9136 leader = inherit_event(parent_event, parent, parent_ctx,
9137 child, NULL, child_ctx);
9139 return PTR_ERR(leader);
9140 list_for_each_entry(sub, &parent_event->sibling_list, group_entry) {
9141 child_ctr = inherit_event(sub, parent, parent_ctx,
9142 child, leader, child_ctx);
9143 if (IS_ERR(child_ctr))
9144 return PTR_ERR(child_ctr);
9150 inherit_task_group(struct perf_event *event, struct task_struct *parent,
9151 struct perf_event_context *parent_ctx,
9152 struct task_struct *child, int ctxn,
9156 struct perf_event_context *child_ctx;
9158 if (!event->attr.inherit) {
9163 child_ctx = child->perf_event_ctxp[ctxn];
9166 * This is executed from the parent task context, so
9167 * inherit events that have been marked for cloning.
9168 * First allocate and initialize a context for the
9172 child_ctx = alloc_perf_context(parent_ctx->pmu, child);
9176 child->perf_event_ctxp[ctxn] = child_ctx;
9179 ret = inherit_group(event, parent, parent_ctx,
9189 * Initialize the perf_event context in task_struct
9191 static int perf_event_init_context(struct task_struct *child, int ctxn)
9193 struct perf_event_context *child_ctx, *parent_ctx;
9194 struct perf_event_context *cloned_ctx;
9195 struct perf_event *event;
9196 struct task_struct *parent = current;
9197 int inherited_all = 1;
9198 unsigned long flags;
9201 if (likely(!parent->perf_event_ctxp[ctxn]))
9205 * If the parent's context is a clone, pin it so it won't get
9208 parent_ctx = perf_pin_task_context(parent, ctxn);
9213 * No need to check if parent_ctx != NULL here; since we saw
9214 * it non-NULL earlier, the only reason for it to become NULL
9215 * is if we exit, and since we're currently in the middle of
9216 * a fork we can't be exiting at the same time.
9220 * Lock the parent list. No need to lock the child - not PID
9221 * hashed yet and not running, so nobody can access it.
9223 mutex_lock(&parent_ctx->mutex);
9226 * We dont have to disable NMIs - we are only looking at
9227 * the list, not manipulating it:
9229 list_for_each_entry(event, &parent_ctx->pinned_groups, group_entry) {
9230 ret = inherit_task_group(event, parent, parent_ctx,
9231 child, ctxn, &inherited_all);
9237 * We can't hold ctx->lock when iterating the ->flexible_group list due
9238 * to allocations, but we need to prevent rotation because
9239 * rotate_ctx() will change the list from interrupt context.
9241 raw_spin_lock_irqsave(&parent_ctx->lock, flags);
9242 parent_ctx->rotate_disable = 1;
9243 raw_spin_unlock_irqrestore(&parent_ctx->lock, flags);
9245 list_for_each_entry(event, &parent_ctx->flexible_groups, group_entry) {
9246 ret = inherit_task_group(event, parent, parent_ctx,
9247 child, ctxn, &inherited_all);
9252 raw_spin_lock_irqsave(&parent_ctx->lock, flags);
9253 parent_ctx->rotate_disable = 0;
9255 child_ctx = child->perf_event_ctxp[ctxn];
9257 if (child_ctx && inherited_all) {
9259 * Mark the child context as a clone of the parent
9260 * context, or of whatever the parent is a clone of.
9262 * Note that if the parent is a clone, the holding of
9263 * parent_ctx->lock avoids it from being uncloned.
9265 cloned_ctx = parent_ctx->parent_ctx;
9267 child_ctx->parent_ctx = cloned_ctx;
9268 child_ctx->parent_gen = parent_ctx->parent_gen;
9270 child_ctx->parent_ctx = parent_ctx;
9271 child_ctx->parent_gen = parent_ctx->generation;
9273 get_ctx(child_ctx->parent_ctx);
9276 raw_spin_unlock_irqrestore(&parent_ctx->lock, flags);
9277 mutex_unlock(&parent_ctx->mutex);
9279 perf_unpin_context(parent_ctx);
9280 put_ctx(parent_ctx);
9286 * Initialize the perf_event context in task_struct
9288 int perf_event_init_task(struct task_struct *child)
9292 memset(child->perf_event_ctxp, 0, sizeof(child->perf_event_ctxp));
9293 mutex_init(&child->perf_event_mutex);
9294 INIT_LIST_HEAD(&child->perf_event_list);
9296 for_each_task_context_nr(ctxn) {
9297 ret = perf_event_init_context(child, ctxn);
9299 perf_event_free_task(child);
9307 static void __init perf_event_init_all_cpus(void)
9309 struct swevent_htable *swhash;
9312 for_each_possible_cpu(cpu) {
9313 swhash = &per_cpu(swevent_htable, cpu);
9314 mutex_init(&swhash->hlist_mutex);
9315 INIT_LIST_HEAD(&per_cpu(active_ctx_list, cpu));
9319 static void perf_event_init_cpu(int cpu)
9321 struct swevent_htable *swhash = &per_cpu(swevent_htable, cpu);
9323 mutex_lock(&swhash->hlist_mutex);
9324 if (swhash->hlist_refcount > 0 && !swevent_hlist_deref(swhash)) {
9325 struct swevent_hlist *hlist;
9327 hlist = kzalloc_node(sizeof(*hlist), GFP_KERNEL, cpu_to_node(cpu));
9329 rcu_assign_pointer(swhash->swevent_hlist, hlist);
9331 mutex_unlock(&swhash->hlist_mutex);
9334 #if defined CONFIG_HOTPLUG_CPU || defined CONFIG_KEXEC_CORE
9335 static void __perf_event_exit_context(void *__info)
9337 struct perf_event_context *ctx = __info;
9338 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
9339 struct perf_event *event;
9341 raw_spin_lock(&ctx->lock);
9342 list_for_each_entry(event, &ctx->event_list, event_entry)
9343 __perf_remove_from_context(event, cpuctx, ctx, (void *)DETACH_GROUP);
9344 raw_spin_unlock(&ctx->lock);
9347 static void perf_event_exit_cpu_context(int cpu)
9349 struct perf_event_context *ctx;
9353 idx = srcu_read_lock(&pmus_srcu);
9354 list_for_each_entry_rcu(pmu, &pmus, entry) {
9355 ctx = &per_cpu_ptr(pmu->pmu_cpu_context, cpu)->ctx;
9357 mutex_lock(&ctx->mutex);
9358 smp_call_function_single(cpu, __perf_event_exit_context, ctx, 1);
9359 mutex_unlock(&ctx->mutex);
9361 srcu_read_unlock(&pmus_srcu, idx);
9364 static void perf_event_exit_cpu(int cpu)
9366 perf_event_exit_cpu_context(cpu);
9369 static inline void perf_event_exit_cpu(int cpu) { }
9373 perf_reboot(struct notifier_block *notifier, unsigned long val, void *v)
9377 for_each_online_cpu(cpu)
9378 perf_event_exit_cpu(cpu);
9384 * Run the perf reboot notifier at the very last possible moment so that
9385 * the generic watchdog code runs as long as possible.
9387 static struct notifier_block perf_reboot_notifier = {
9388 .notifier_call = perf_reboot,
9389 .priority = INT_MIN,
9393 perf_cpu_notify(struct notifier_block *self, unsigned long action, void *hcpu)
9395 unsigned int cpu = (long)hcpu;
9397 switch (action & ~CPU_TASKS_FROZEN) {
9399 case CPU_UP_PREPARE:
9400 perf_event_init_cpu(cpu);
9403 case CPU_DOWN_PREPARE:
9404 perf_event_exit_cpu(cpu);
9413 void __init perf_event_init(void)
9419 perf_event_init_all_cpus();
9420 init_srcu_struct(&pmus_srcu);
9421 perf_pmu_register(&perf_swevent, "software", PERF_TYPE_SOFTWARE);
9422 perf_pmu_register(&perf_cpu_clock, NULL, -1);
9423 perf_pmu_register(&perf_task_clock, NULL, -1);
9425 perf_cpu_notifier(perf_cpu_notify);
9426 register_reboot_notifier(&perf_reboot_notifier);
9428 ret = init_hw_breakpoint();
9429 WARN(ret, "hw_breakpoint initialization failed with: %d", ret);
9432 * Build time assertion that we keep the data_head at the intended
9433 * location. IOW, validation we got the __reserved[] size right.
9435 BUILD_BUG_ON((offsetof(struct perf_event_mmap_page, data_head))
9439 ssize_t perf_event_sysfs_show(struct device *dev, struct device_attribute *attr,
9442 struct perf_pmu_events_attr *pmu_attr =
9443 container_of(attr, struct perf_pmu_events_attr, attr);
9445 if (pmu_attr->event_str)
9446 return sprintf(page, "%s\n", pmu_attr->event_str);
9451 static int __init perf_event_sysfs_init(void)
9456 mutex_lock(&pmus_lock);
9458 ret = bus_register(&pmu_bus);
9462 list_for_each_entry(pmu, &pmus, entry) {
9463 if (!pmu->name || pmu->type < 0)
9466 ret = pmu_dev_alloc(pmu);
9467 WARN(ret, "Failed to register pmu: %s, reason %d\n", pmu->name, ret);
9469 pmu_bus_running = 1;
9473 mutex_unlock(&pmus_lock);
9477 device_initcall(perf_event_sysfs_init);
9479 #ifdef CONFIG_CGROUP_PERF
9480 static struct cgroup_subsys_state *
9481 perf_cgroup_css_alloc(struct cgroup_subsys_state *parent_css)
9483 struct perf_cgroup *jc;
9485 jc = kzalloc(sizeof(*jc), GFP_KERNEL);
9487 return ERR_PTR(-ENOMEM);
9489 jc->info = alloc_percpu(struct perf_cgroup_info);
9492 return ERR_PTR(-ENOMEM);
9498 static void perf_cgroup_css_free(struct cgroup_subsys_state *css)
9500 struct perf_cgroup *jc = container_of(css, struct perf_cgroup, css);
9502 free_percpu(jc->info);
9506 static int __perf_cgroup_move(void *info)
9508 struct task_struct *task = info;
9510 perf_cgroup_switch(task, PERF_CGROUP_SWOUT | PERF_CGROUP_SWIN);
9515 static void perf_cgroup_attach(struct cgroup_taskset *tset)
9517 struct task_struct *task;
9518 struct cgroup_subsys_state *css;
9520 cgroup_taskset_for_each(task, css, tset)
9521 task_function_call(task, __perf_cgroup_move, task);
9524 struct cgroup_subsys perf_event_cgrp_subsys = {
9525 .css_alloc = perf_cgroup_css_alloc,
9526 .css_free = perf_cgroup_css_free,
9527 .attach = perf_cgroup_attach,
9529 #endif /* CONFIG_CGROUP_PERF */