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>
47 #include <linux/namei.h>
48 #include <linux/parser.h>
52 #include <asm/irq_regs.h>
54 typedef int (*remote_function_f)(void *);
56 struct remote_function_call {
57 struct task_struct *p;
58 remote_function_f func;
63 static void remote_function(void *data)
65 struct remote_function_call *tfc = data;
66 struct task_struct *p = tfc->p;
70 if (task_cpu(p) != smp_processor_id())
74 * Now that we're on right CPU with IRQs disabled, we can test
75 * if we hit the right task without races.
78 tfc->ret = -ESRCH; /* No such (running) process */
83 tfc->ret = tfc->func(tfc->info);
87 * task_function_call - call a function on the cpu on which a task runs
88 * @p: the task to evaluate
89 * @func: the function to be called
90 * @info: the function call argument
92 * Calls the function @func when the task is currently running. This might
93 * be on the current CPU, which just calls the function directly
95 * returns: @func return value, or
96 * -ESRCH - when the process isn't running
97 * -EAGAIN - when the process moved away
100 task_function_call(struct task_struct *p, remote_function_f func, void *info)
102 struct remote_function_call data = {
111 ret = smp_call_function_single(task_cpu(p), remote_function, &data, 1);
114 } while (ret == -EAGAIN);
120 * cpu_function_call - call a function on the cpu
121 * @func: the function to be called
122 * @info: the function call argument
124 * Calls the function @func on the remote cpu.
126 * returns: @func return value or -ENXIO when the cpu is offline
128 static int cpu_function_call(int cpu, remote_function_f func, void *info)
130 struct remote_function_call data = {
134 .ret = -ENXIO, /* No such CPU */
137 smp_call_function_single(cpu, remote_function, &data, 1);
142 static inline struct perf_cpu_context *
143 __get_cpu_context(struct perf_event_context *ctx)
145 return this_cpu_ptr(ctx->pmu->pmu_cpu_context);
148 static void perf_ctx_lock(struct perf_cpu_context *cpuctx,
149 struct perf_event_context *ctx)
151 raw_spin_lock(&cpuctx->ctx.lock);
153 raw_spin_lock(&ctx->lock);
156 static void perf_ctx_unlock(struct perf_cpu_context *cpuctx,
157 struct perf_event_context *ctx)
160 raw_spin_unlock(&ctx->lock);
161 raw_spin_unlock(&cpuctx->ctx.lock);
164 #define TASK_TOMBSTONE ((void *)-1L)
166 static bool is_kernel_event(struct perf_event *event)
168 return READ_ONCE(event->owner) == TASK_TOMBSTONE;
172 * On task ctx scheduling...
174 * When !ctx->nr_events a task context will not be scheduled. This means
175 * we can disable the scheduler hooks (for performance) without leaving
176 * pending task ctx state.
178 * This however results in two special cases:
180 * - removing the last event from a task ctx; this is relatively straight
181 * forward and is done in __perf_remove_from_context.
183 * - adding the first event to a task ctx; this is tricky because we cannot
184 * rely on ctx->is_active and therefore cannot use event_function_call().
185 * See perf_install_in_context().
187 * If ctx->nr_events, then ctx->is_active and cpuctx->task_ctx are set.
190 typedef void (*event_f)(struct perf_event *, struct perf_cpu_context *,
191 struct perf_event_context *, void *);
193 struct event_function_struct {
194 struct perf_event *event;
199 static int event_function(void *info)
201 struct event_function_struct *efs = info;
202 struct perf_event *event = efs->event;
203 struct perf_event_context *ctx = event->ctx;
204 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
205 struct perf_event_context *task_ctx = cpuctx->task_ctx;
208 WARN_ON_ONCE(!irqs_disabled());
210 perf_ctx_lock(cpuctx, task_ctx);
212 * Since we do the IPI call without holding ctx->lock things can have
213 * changed, double check we hit the task we set out to hit.
216 if (ctx->task != current) {
222 * We only use event_function_call() on established contexts,
223 * and event_function() is only ever called when active (or
224 * rather, we'll have bailed in task_function_call() or the
225 * above ctx->task != current test), therefore we must have
226 * ctx->is_active here.
228 WARN_ON_ONCE(!ctx->is_active);
230 * And since we have ctx->is_active, cpuctx->task_ctx must
233 WARN_ON_ONCE(task_ctx != ctx);
235 WARN_ON_ONCE(&cpuctx->ctx != ctx);
238 efs->func(event, cpuctx, ctx, efs->data);
240 perf_ctx_unlock(cpuctx, task_ctx);
245 static void event_function_local(struct perf_event *event, event_f func, void *data)
247 struct event_function_struct efs = {
253 int ret = event_function(&efs);
257 static void event_function_call(struct perf_event *event, event_f func, void *data)
259 struct perf_event_context *ctx = event->ctx;
260 struct task_struct *task = READ_ONCE(ctx->task); /* verified in event_function */
261 struct event_function_struct efs = {
267 if (!event->parent) {
269 * If this is a !child event, we must hold ctx::mutex to
270 * stabilize the the event->ctx relation. See
271 * perf_event_ctx_lock().
273 lockdep_assert_held(&ctx->mutex);
277 cpu_function_call(event->cpu, event_function, &efs);
281 if (task == TASK_TOMBSTONE)
285 if (!task_function_call(task, event_function, &efs))
288 raw_spin_lock_irq(&ctx->lock);
290 * Reload the task pointer, it might have been changed by
291 * a concurrent perf_event_context_sched_out().
294 if (task == TASK_TOMBSTONE) {
295 raw_spin_unlock_irq(&ctx->lock);
298 if (ctx->is_active) {
299 raw_spin_unlock_irq(&ctx->lock);
302 func(event, NULL, ctx, data);
303 raw_spin_unlock_irq(&ctx->lock);
306 #define PERF_FLAG_ALL (PERF_FLAG_FD_NO_GROUP |\
307 PERF_FLAG_FD_OUTPUT |\
308 PERF_FLAG_PID_CGROUP |\
309 PERF_FLAG_FD_CLOEXEC)
312 * branch priv levels that need permission checks
314 #define PERF_SAMPLE_BRANCH_PERM_PLM \
315 (PERF_SAMPLE_BRANCH_KERNEL |\
316 PERF_SAMPLE_BRANCH_HV)
319 EVENT_FLEXIBLE = 0x1,
322 EVENT_ALL = EVENT_FLEXIBLE | EVENT_PINNED,
326 * perf_sched_events : >0 events exist
327 * perf_cgroup_events: >0 per-cpu cgroup events exist on this cpu
330 static void perf_sched_delayed(struct work_struct *work);
331 DEFINE_STATIC_KEY_FALSE(perf_sched_events);
332 static DECLARE_DELAYED_WORK(perf_sched_work, perf_sched_delayed);
333 static DEFINE_MUTEX(perf_sched_mutex);
334 static atomic_t perf_sched_count;
336 static DEFINE_PER_CPU(atomic_t, perf_cgroup_events);
337 static DEFINE_PER_CPU(int, perf_sched_cb_usages);
338 static DEFINE_PER_CPU(struct pmu_event_list, pmu_sb_events);
340 static atomic_t nr_mmap_events __read_mostly;
341 static atomic_t nr_comm_events __read_mostly;
342 static atomic_t nr_task_events __read_mostly;
343 static atomic_t nr_freq_events __read_mostly;
344 static atomic_t nr_switch_events __read_mostly;
346 static LIST_HEAD(pmus);
347 static DEFINE_MUTEX(pmus_lock);
348 static struct srcu_struct pmus_srcu;
351 * perf event paranoia level:
352 * -1 - not paranoid at all
353 * 0 - disallow raw tracepoint access for unpriv
354 * 1 - disallow cpu events for unpriv
355 * 2 - disallow kernel profiling for unpriv
357 int sysctl_perf_event_paranoid __read_mostly = 2;
359 /* Minimum for 512 kiB + 1 user control page */
360 int sysctl_perf_event_mlock __read_mostly = 512 + (PAGE_SIZE / 1024); /* 'free' kiB per user */
363 * max perf event sample rate
365 #define DEFAULT_MAX_SAMPLE_RATE 100000
366 #define DEFAULT_SAMPLE_PERIOD_NS (NSEC_PER_SEC / DEFAULT_MAX_SAMPLE_RATE)
367 #define DEFAULT_CPU_TIME_MAX_PERCENT 25
369 int sysctl_perf_event_sample_rate __read_mostly = DEFAULT_MAX_SAMPLE_RATE;
371 static int max_samples_per_tick __read_mostly = DIV_ROUND_UP(DEFAULT_MAX_SAMPLE_RATE, HZ);
372 static int perf_sample_period_ns __read_mostly = DEFAULT_SAMPLE_PERIOD_NS;
374 static int perf_sample_allowed_ns __read_mostly =
375 DEFAULT_SAMPLE_PERIOD_NS * DEFAULT_CPU_TIME_MAX_PERCENT / 100;
377 static void update_perf_cpu_limits(void)
379 u64 tmp = perf_sample_period_ns;
381 tmp *= sysctl_perf_cpu_time_max_percent;
382 tmp = div_u64(tmp, 100);
386 WRITE_ONCE(perf_sample_allowed_ns, tmp);
389 static int perf_rotate_context(struct perf_cpu_context *cpuctx);
391 int perf_proc_update_handler(struct ctl_table *table, int write,
392 void __user *buffer, size_t *lenp,
395 int ret = proc_dointvec_minmax(table, write, buffer, lenp, ppos);
401 * If throttling is disabled don't allow the write:
403 if (sysctl_perf_cpu_time_max_percent == 100 ||
404 sysctl_perf_cpu_time_max_percent == 0)
407 max_samples_per_tick = DIV_ROUND_UP(sysctl_perf_event_sample_rate, HZ);
408 perf_sample_period_ns = NSEC_PER_SEC / sysctl_perf_event_sample_rate;
409 update_perf_cpu_limits();
414 int sysctl_perf_cpu_time_max_percent __read_mostly = DEFAULT_CPU_TIME_MAX_PERCENT;
416 int perf_cpu_time_max_percent_handler(struct ctl_table *table, int write,
417 void __user *buffer, size_t *lenp,
420 int ret = proc_dointvec(table, write, buffer, lenp, ppos);
425 if (sysctl_perf_cpu_time_max_percent == 100 ||
426 sysctl_perf_cpu_time_max_percent == 0) {
428 "perf: Dynamic interrupt throttling disabled, can hang your system!\n");
429 WRITE_ONCE(perf_sample_allowed_ns, 0);
431 update_perf_cpu_limits();
438 * perf samples are done in some very critical code paths (NMIs).
439 * If they take too much CPU time, the system can lock up and not
440 * get any real work done. This will drop the sample rate when
441 * we detect that events are taking too long.
443 #define NR_ACCUMULATED_SAMPLES 128
444 static DEFINE_PER_CPU(u64, running_sample_length);
446 static u64 __report_avg;
447 static u64 __report_allowed;
449 static void perf_duration_warn(struct irq_work *w)
451 printk_ratelimited(KERN_INFO
452 "perf: interrupt took too long (%lld > %lld), lowering "
453 "kernel.perf_event_max_sample_rate to %d\n",
454 __report_avg, __report_allowed,
455 sysctl_perf_event_sample_rate);
458 static DEFINE_IRQ_WORK(perf_duration_work, perf_duration_warn);
460 void perf_sample_event_took(u64 sample_len_ns)
462 u64 max_len = READ_ONCE(perf_sample_allowed_ns);
470 /* Decay the counter by 1 average sample. */
471 running_len = __this_cpu_read(running_sample_length);
472 running_len -= running_len/NR_ACCUMULATED_SAMPLES;
473 running_len += sample_len_ns;
474 __this_cpu_write(running_sample_length, running_len);
477 * Note: this will be biased artifically low until we have
478 * seen NR_ACCUMULATED_SAMPLES. Doing it this way keeps us
479 * from having to maintain a count.
481 avg_len = running_len/NR_ACCUMULATED_SAMPLES;
482 if (avg_len <= max_len)
485 __report_avg = avg_len;
486 __report_allowed = max_len;
489 * Compute a throttle threshold 25% below the current duration.
491 avg_len += avg_len / 4;
492 max = (TICK_NSEC / 100) * sysctl_perf_cpu_time_max_percent;
498 WRITE_ONCE(perf_sample_allowed_ns, avg_len);
499 WRITE_ONCE(max_samples_per_tick, max);
501 sysctl_perf_event_sample_rate = max * HZ;
502 perf_sample_period_ns = NSEC_PER_SEC / sysctl_perf_event_sample_rate;
504 if (!irq_work_queue(&perf_duration_work)) {
505 early_printk("perf: interrupt took too long (%lld > %lld), lowering "
506 "kernel.perf_event_max_sample_rate to %d\n",
507 __report_avg, __report_allowed,
508 sysctl_perf_event_sample_rate);
512 static atomic64_t perf_event_id;
514 static void cpu_ctx_sched_out(struct perf_cpu_context *cpuctx,
515 enum event_type_t event_type);
517 static void cpu_ctx_sched_in(struct perf_cpu_context *cpuctx,
518 enum event_type_t event_type,
519 struct task_struct *task);
521 static void update_context_time(struct perf_event_context *ctx);
522 static u64 perf_event_time(struct perf_event *event);
524 void __weak perf_event_print_debug(void) { }
526 extern __weak const char *perf_pmu_name(void)
531 static inline u64 perf_clock(void)
533 return local_clock();
536 static inline u64 perf_event_clock(struct perf_event *event)
538 return event->clock();
541 #ifdef CONFIG_CGROUP_PERF
544 perf_cgroup_match(struct perf_event *event)
546 struct perf_event_context *ctx = event->ctx;
547 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
549 /* @event doesn't care about cgroup */
553 /* wants specific cgroup scope but @cpuctx isn't associated with any */
558 * Cgroup scoping is recursive. An event enabled for a cgroup is
559 * also enabled for all its descendant cgroups. If @cpuctx's
560 * cgroup is a descendant of @event's (the test covers identity
561 * case), it's a match.
563 return cgroup_is_descendant(cpuctx->cgrp->css.cgroup,
564 event->cgrp->css.cgroup);
567 static inline void perf_detach_cgroup(struct perf_event *event)
569 css_put(&event->cgrp->css);
573 static inline int is_cgroup_event(struct perf_event *event)
575 return event->cgrp != NULL;
578 static inline u64 perf_cgroup_event_time(struct perf_event *event)
580 struct perf_cgroup_info *t;
582 t = per_cpu_ptr(event->cgrp->info, event->cpu);
586 static inline void __update_cgrp_time(struct perf_cgroup *cgrp)
588 struct perf_cgroup_info *info;
593 info = this_cpu_ptr(cgrp->info);
595 info->time += now - info->timestamp;
596 info->timestamp = now;
599 static inline void update_cgrp_time_from_cpuctx(struct perf_cpu_context *cpuctx)
601 struct perf_cgroup *cgrp_out = cpuctx->cgrp;
603 __update_cgrp_time(cgrp_out);
606 static inline void update_cgrp_time_from_event(struct perf_event *event)
608 struct perf_cgroup *cgrp;
611 * ensure we access cgroup data only when needed and
612 * when we know the cgroup is pinned (css_get)
614 if (!is_cgroup_event(event))
617 cgrp = perf_cgroup_from_task(current, event->ctx);
619 * Do not update time when cgroup is not active
621 if (cgrp == event->cgrp)
622 __update_cgrp_time(event->cgrp);
626 perf_cgroup_set_timestamp(struct task_struct *task,
627 struct perf_event_context *ctx)
629 struct perf_cgroup *cgrp;
630 struct perf_cgroup_info *info;
633 * ctx->lock held by caller
634 * ensure we do not access cgroup data
635 * unless we have the cgroup pinned (css_get)
637 if (!task || !ctx->nr_cgroups)
640 cgrp = perf_cgroup_from_task(task, ctx);
641 info = this_cpu_ptr(cgrp->info);
642 info->timestamp = ctx->timestamp;
645 #define PERF_CGROUP_SWOUT 0x1 /* cgroup switch out every event */
646 #define PERF_CGROUP_SWIN 0x2 /* cgroup switch in events based on task */
649 * reschedule events based on the cgroup constraint of task.
651 * mode SWOUT : schedule out everything
652 * mode SWIN : schedule in based on cgroup for next
654 static void perf_cgroup_switch(struct task_struct *task, int mode)
656 struct perf_cpu_context *cpuctx;
661 * disable interrupts to avoid geting nr_cgroup
662 * changes via __perf_event_disable(). Also
665 local_irq_save(flags);
668 * we reschedule only in the presence of cgroup
669 * constrained events.
672 list_for_each_entry_rcu(pmu, &pmus, entry) {
673 cpuctx = this_cpu_ptr(pmu->pmu_cpu_context);
674 if (cpuctx->unique_pmu != pmu)
675 continue; /* ensure we process each cpuctx once */
678 * perf_cgroup_events says at least one
679 * context on this CPU has cgroup events.
681 * ctx->nr_cgroups reports the number of cgroup
682 * events for a context.
684 if (cpuctx->ctx.nr_cgroups > 0) {
685 perf_ctx_lock(cpuctx, cpuctx->task_ctx);
686 perf_pmu_disable(cpuctx->ctx.pmu);
688 if (mode & PERF_CGROUP_SWOUT) {
689 cpu_ctx_sched_out(cpuctx, EVENT_ALL);
691 * must not be done before ctxswout due
692 * to event_filter_match() in event_sched_out()
697 if (mode & PERF_CGROUP_SWIN) {
698 WARN_ON_ONCE(cpuctx->cgrp);
700 * set cgrp before ctxsw in to allow
701 * event_filter_match() to not have to pass
703 * we pass the cpuctx->ctx to perf_cgroup_from_task()
704 * because cgorup events are only per-cpu
706 cpuctx->cgrp = perf_cgroup_from_task(task, &cpuctx->ctx);
707 cpu_ctx_sched_in(cpuctx, EVENT_ALL, task);
709 perf_pmu_enable(cpuctx->ctx.pmu);
710 perf_ctx_unlock(cpuctx, cpuctx->task_ctx);
714 local_irq_restore(flags);
717 static inline void perf_cgroup_sched_out(struct task_struct *task,
718 struct task_struct *next)
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(next, NULL);
733 * only schedule out current cgroup events if we know
734 * that we are switching to a different cgroup. Otherwise,
735 * do no touch the cgroup events.
738 perf_cgroup_switch(task, PERF_CGROUP_SWOUT);
743 static inline void perf_cgroup_sched_in(struct task_struct *prev,
744 struct task_struct *task)
746 struct perf_cgroup *cgrp1;
747 struct perf_cgroup *cgrp2 = NULL;
751 * we come here when we know perf_cgroup_events > 0
752 * we do not need to pass the ctx here because we know
753 * we are holding the rcu lock
755 cgrp1 = perf_cgroup_from_task(task, NULL);
756 cgrp2 = perf_cgroup_from_task(prev, NULL);
759 * only need to schedule in cgroup events if we are changing
760 * cgroup during ctxsw. Cgroup events were not scheduled
761 * out of ctxsw out if that was not the case.
764 perf_cgroup_switch(task, PERF_CGROUP_SWIN);
769 static inline int perf_cgroup_connect(int fd, struct perf_event *event,
770 struct perf_event_attr *attr,
771 struct perf_event *group_leader)
773 struct perf_cgroup *cgrp;
774 struct cgroup_subsys_state *css;
775 struct fd f = fdget(fd);
781 css = css_tryget_online_from_dir(f.file->f_path.dentry,
782 &perf_event_cgrp_subsys);
788 cgrp = container_of(css, struct perf_cgroup, css);
792 * all events in a group must monitor
793 * the same cgroup because a task belongs
794 * to only one perf cgroup at a time
796 if (group_leader && group_leader->cgrp != cgrp) {
797 perf_detach_cgroup(event);
806 perf_cgroup_set_shadow_time(struct perf_event *event, u64 now)
808 struct perf_cgroup_info *t;
809 t = per_cpu_ptr(event->cgrp->info, event->cpu);
810 event->shadow_ctx_time = now - t->timestamp;
814 perf_cgroup_defer_enabled(struct perf_event *event)
817 * when the current task's perf cgroup does not match
818 * the event's, we need to remember to call the
819 * perf_mark_enable() function the first time a task with
820 * a matching perf cgroup is scheduled in.
822 if (is_cgroup_event(event) && !perf_cgroup_match(event))
823 event->cgrp_defer_enabled = 1;
827 perf_cgroup_mark_enabled(struct perf_event *event,
828 struct perf_event_context *ctx)
830 struct perf_event *sub;
831 u64 tstamp = perf_event_time(event);
833 if (!event->cgrp_defer_enabled)
836 event->cgrp_defer_enabled = 0;
838 event->tstamp_enabled = tstamp - event->total_time_enabled;
839 list_for_each_entry(sub, &event->sibling_list, group_entry) {
840 if (sub->state >= PERF_EVENT_STATE_INACTIVE) {
841 sub->tstamp_enabled = tstamp - sub->total_time_enabled;
842 sub->cgrp_defer_enabled = 0;
846 #else /* !CONFIG_CGROUP_PERF */
849 perf_cgroup_match(struct perf_event *event)
854 static inline void perf_detach_cgroup(struct perf_event *event)
857 static inline int is_cgroup_event(struct perf_event *event)
862 static inline u64 perf_cgroup_event_cgrp_time(struct perf_event *event)
867 static inline void update_cgrp_time_from_event(struct perf_event *event)
871 static inline void update_cgrp_time_from_cpuctx(struct perf_cpu_context *cpuctx)
875 static inline void perf_cgroup_sched_out(struct task_struct *task,
876 struct task_struct *next)
880 static inline void perf_cgroup_sched_in(struct task_struct *prev,
881 struct task_struct *task)
885 static inline int perf_cgroup_connect(pid_t pid, struct perf_event *event,
886 struct perf_event_attr *attr,
887 struct perf_event *group_leader)
893 perf_cgroup_set_timestamp(struct task_struct *task,
894 struct perf_event_context *ctx)
899 perf_cgroup_switch(struct task_struct *task, struct task_struct *next)
904 perf_cgroup_set_shadow_time(struct perf_event *event, u64 now)
908 static inline u64 perf_cgroup_event_time(struct perf_event *event)
914 perf_cgroup_defer_enabled(struct perf_event *event)
919 perf_cgroup_mark_enabled(struct perf_event *event,
920 struct perf_event_context *ctx)
926 * set default to be dependent on timer tick just
929 #define PERF_CPU_HRTIMER (1000 / HZ)
931 * function must be called with interrupts disbled
933 static enum hrtimer_restart perf_mux_hrtimer_handler(struct hrtimer *hr)
935 struct perf_cpu_context *cpuctx;
938 WARN_ON(!irqs_disabled());
940 cpuctx = container_of(hr, struct perf_cpu_context, hrtimer);
941 rotations = perf_rotate_context(cpuctx);
943 raw_spin_lock(&cpuctx->hrtimer_lock);
945 hrtimer_forward_now(hr, cpuctx->hrtimer_interval);
947 cpuctx->hrtimer_active = 0;
948 raw_spin_unlock(&cpuctx->hrtimer_lock);
950 return rotations ? HRTIMER_RESTART : HRTIMER_NORESTART;
953 static void __perf_mux_hrtimer_init(struct perf_cpu_context *cpuctx, int cpu)
955 struct hrtimer *timer = &cpuctx->hrtimer;
956 struct pmu *pmu = cpuctx->ctx.pmu;
959 /* no multiplexing needed for SW PMU */
960 if (pmu->task_ctx_nr == perf_sw_context)
964 * check default is sane, if not set then force to
965 * default interval (1/tick)
967 interval = pmu->hrtimer_interval_ms;
969 interval = pmu->hrtimer_interval_ms = PERF_CPU_HRTIMER;
971 cpuctx->hrtimer_interval = ns_to_ktime(NSEC_PER_MSEC * interval);
973 raw_spin_lock_init(&cpuctx->hrtimer_lock);
974 hrtimer_init(timer, CLOCK_MONOTONIC, HRTIMER_MODE_ABS_PINNED);
975 timer->function = perf_mux_hrtimer_handler;
978 static int perf_mux_hrtimer_restart(struct perf_cpu_context *cpuctx)
980 struct hrtimer *timer = &cpuctx->hrtimer;
981 struct pmu *pmu = cpuctx->ctx.pmu;
985 if (pmu->task_ctx_nr == perf_sw_context)
988 raw_spin_lock_irqsave(&cpuctx->hrtimer_lock, flags);
989 if (!cpuctx->hrtimer_active) {
990 cpuctx->hrtimer_active = 1;
991 hrtimer_forward_now(timer, cpuctx->hrtimer_interval);
992 hrtimer_start_expires(timer, HRTIMER_MODE_ABS_PINNED);
994 raw_spin_unlock_irqrestore(&cpuctx->hrtimer_lock, flags);
999 void perf_pmu_disable(struct pmu *pmu)
1001 int *count = this_cpu_ptr(pmu->pmu_disable_count);
1003 pmu->pmu_disable(pmu);
1006 void perf_pmu_enable(struct pmu *pmu)
1008 int *count = this_cpu_ptr(pmu->pmu_disable_count);
1010 pmu->pmu_enable(pmu);
1013 static DEFINE_PER_CPU(struct list_head, active_ctx_list);
1016 * perf_event_ctx_activate(), perf_event_ctx_deactivate(), and
1017 * perf_event_task_tick() are fully serialized because they're strictly cpu
1018 * affine and perf_event_ctx{activate,deactivate} are called with IRQs
1019 * disabled, while perf_event_task_tick is called from IRQ context.
1021 static void perf_event_ctx_activate(struct perf_event_context *ctx)
1023 struct list_head *head = this_cpu_ptr(&active_ctx_list);
1025 WARN_ON(!irqs_disabled());
1027 WARN_ON(!list_empty(&ctx->active_ctx_list));
1029 list_add(&ctx->active_ctx_list, head);
1032 static void perf_event_ctx_deactivate(struct perf_event_context *ctx)
1034 WARN_ON(!irqs_disabled());
1036 WARN_ON(list_empty(&ctx->active_ctx_list));
1038 list_del_init(&ctx->active_ctx_list);
1041 static void get_ctx(struct perf_event_context *ctx)
1043 WARN_ON(!atomic_inc_not_zero(&ctx->refcount));
1046 static void free_ctx(struct rcu_head *head)
1048 struct perf_event_context *ctx;
1050 ctx = container_of(head, struct perf_event_context, rcu_head);
1051 kfree(ctx->task_ctx_data);
1055 static void put_ctx(struct perf_event_context *ctx)
1057 if (atomic_dec_and_test(&ctx->refcount)) {
1058 if (ctx->parent_ctx)
1059 put_ctx(ctx->parent_ctx);
1060 if (ctx->task && ctx->task != TASK_TOMBSTONE)
1061 put_task_struct(ctx->task);
1062 call_rcu(&ctx->rcu_head, free_ctx);
1067 * Because of perf_event::ctx migration in sys_perf_event_open::move_group and
1068 * perf_pmu_migrate_context() we need some magic.
1070 * Those places that change perf_event::ctx will hold both
1071 * perf_event_ctx::mutex of the 'old' and 'new' ctx value.
1073 * Lock ordering is by mutex address. There are two other sites where
1074 * perf_event_context::mutex nests and those are:
1076 * - perf_event_exit_task_context() [ child , 0 ]
1077 * perf_event_exit_event()
1078 * put_event() [ parent, 1 ]
1080 * - perf_event_init_context() [ parent, 0 ]
1081 * inherit_task_group()
1084 * perf_event_alloc()
1086 * perf_try_init_event() [ child , 1 ]
1088 * While it appears there is an obvious deadlock here -- the parent and child
1089 * nesting levels are inverted between the two. This is in fact safe because
1090 * life-time rules separate them. That is an exiting task cannot fork, and a
1091 * spawning task cannot (yet) exit.
1093 * But remember that that these are parent<->child context relations, and
1094 * migration does not affect children, therefore these two orderings should not
1097 * The change in perf_event::ctx does not affect children (as claimed above)
1098 * because the sys_perf_event_open() case will install a new event and break
1099 * the ctx parent<->child relation, and perf_pmu_migrate_context() is only
1100 * concerned with cpuctx and that doesn't have children.
1102 * The places that change perf_event::ctx will issue:
1104 * perf_remove_from_context();
1105 * synchronize_rcu();
1106 * perf_install_in_context();
1108 * to affect the change. The remove_from_context() + synchronize_rcu() should
1109 * quiesce the event, after which we can install it in the new location. This
1110 * means that only external vectors (perf_fops, prctl) can perturb the event
1111 * while in transit. Therefore all such accessors should also acquire
1112 * perf_event_context::mutex to serialize against this.
1114 * However; because event->ctx can change while we're waiting to acquire
1115 * ctx->mutex we must be careful and use the below perf_event_ctx_lock()
1120 * task_struct::perf_event_mutex
1121 * perf_event_context::mutex
1122 * perf_event::child_mutex;
1123 * perf_event_context::lock
1124 * perf_event::mmap_mutex
1127 static struct perf_event_context *
1128 perf_event_ctx_lock_nested(struct perf_event *event, int nesting)
1130 struct perf_event_context *ctx;
1134 ctx = ACCESS_ONCE(event->ctx);
1135 if (!atomic_inc_not_zero(&ctx->refcount)) {
1141 mutex_lock_nested(&ctx->mutex, nesting);
1142 if (event->ctx != ctx) {
1143 mutex_unlock(&ctx->mutex);
1151 static inline struct perf_event_context *
1152 perf_event_ctx_lock(struct perf_event *event)
1154 return perf_event_ctx_lock_nested(event, 0);
1157 static void perf_event_ctx_unlock(struct perf_event *event,
1158 struct perf_event_context *ctx)
1160 mutex_unlock(&ctx->mutex);
1165 * This must be done under the ctx->lock, such as to serialize against
1166 * context_equiv(), therefore we cannot call put_ctx() since that might end up
1167 * calling scheduler related locks and ctx->lock nests inside those.
1169 static __must_check struct perf_event_context *
1170 unclone_ctx(struct perf_event_context *ctx)
1172 struct perf_event_context *parent_ctx = ctx->parent_ctx;
1174 lockdep_assert_held(&ctx->lock);
1177 ctx->parent_ctx = NULL;
1183 static u32 perf_event_pid(struct perf_event *event, struct task_struct *p)
1186 * only top level events have the pid namespace they were created in
1189 event = event->parent;
1191 return task_tgid_nr_ns(p, event->ns);
1194 static u32 perf_event_tid(struct perf_event *event, struct task_struct *p)
1197 * only top level events have the pid namespace they were created in
1200 event = event->parent;
1202 return task_pid_nr_ns(p, event->ns);
1206 * If we inherit events we want to return the parent event id
1209 static u64 primary_event_id(struct perf_event *event)
1214 id = event->parent->id;
1220 * Get the perf_event_context for a task and lock it.
1222 * This has to cope with with the fact that until it is locked,
1223 * the context could get moved to another task.
1225 static struct perf_event_context *
1226 perf_lock_task_context(struct task_struct *task, int ctxn, unsigned long *flags)
1228 struct perf_event_context *ctx;
1232 * One of the few rules of preemptible RCU is that one cannot do
1233 * rcu_read_unlock() while holding a scheduler (or nested) lock when
1234 * part of the read side critical section was irqs-enabled -- see
1235 * rcu_read_unlock_special().
1237 * Since ctx->lock nests under rq->lock we must ensure the entire read
1238 * side critical section has interrupts disabled.
1240 local_irq_save(*flags);
1242 ctx = rcu_dereference(task->perf_event_ctxp[ctxn]);
1245 * If this context is a clone of another, it might
1246 * get swapped for another underneath us by
1247 * perf_event_task_sched_out, though the
1248 * rcu_read_lock() protects us from any context
1249 * getting freed. Lock the context and check if it
1250 * got swapped before we could get the lock, and retry
1251 * if so. If we locked the right context, then it
1252 * can't get swapped on us any more.
1254 raw_spin_lock(&ctx->lock);
1255 if (ctx != rcu_dereference(task->perf_event_ctxp[ctxn])) {
1256 raw_spin_unlock(&ctx->lock);
1258 local_irq_restore(*flags);
1262 if (ctx->task == TASK_TOMBSTONE ||
1263 !atomic_inc_not_zero(&ctx->refcount)) {
1264 raw_spin_unlock(&ctx->lock);
1267 WARN_ON_ONCE(ctx->task != task);
1272 local_irq_restore(*flags);
1277 * Get the context for a task and increment its pin_count so it
1278 * can't get swapped to another task. This also increments its
1279 * reference count so that the context can't get freed.
1281 static struct perf_event_context *
1282 perf_pin_task_context(struct task_struct *task, int ctxn)
1284 struct perf_event_context *ctx;
1285 unsigned long flags;
1287 ctx = perf_lock_task_context(task, ctxn, &flags);
1290 raw_spin_unlock_irqrestore(&ctx->lock, flags);
1295 static void perf_unpin_context(struct perf_event_context *ctx)
1297 unsigned long flags;
1299 raw_spin_lock_irqsave(&ctx->lock, flags);
1301 raw_spin_unlock_irqrestore(&ctx->lock, flags);
1305 * Update the record of the current time in a context.
1307 static void update_context_time(struct perf_event_context *ctx)
1309 u64 now = perf_clock();
1311 ctx->time += now - ctx->timestamp;
1312 ctx->timestamp = now;
1315 static u64 perf_event_time(struct perf_event *event)
1317 struct perf_event_context *ctx = event->ctx;
1319 if (is_cgroup_event(event))
1320 return perf_cgroup_event_time(event);
1322 return ctx ? ctx->time : 0;
1326 * Update the total_time_enabled and total_time_running fields for a event.
1328 static void update_event_times(struct perf_event *event)
1330 struct perf_event_context *ctx = event->ctx;
1333 lockdep_assert_held(&ctx->lock);
1335 if (event->state < PERF_EVENT_STATE_INACTIVE ||
1336 event->group_leader->state < PERF_EVENT_STATE_INACTIVE)
1340 * in cgroup mode, time_enabled represents
1341 * the time the event was enabled AND active
1342 * tasks were in the monitored cgroup. This is
1343 * independent of the activity of the context as
1344 * there may be a mix of cgroup and non-cgroup events.
1346 * That is why we treat cgroup events differently
1349 if (is_cgroup_event(event))
1350 run_end = perf_cgroup_event_time(event);
1351 else if (ctx->is_active)
1352 run_end = ctx->time;
1354 run_end = event->tstamp_stopped;
1356 event->total_time_enabled = run_end - event->tstamp_enabled;
1358 if (event->state == PERF_EVENT_STATE_INACTIVE)
1359 run_end = event->tstamp_stopped;
1361 run_end = perf_event_time(event);
1363 event->total_time_running = run_end - event->tstamp_running;
1368 * Update total_time_enabled and total_time_running for all events in a group.
1370 static void update_group_times(struct perf_event *leader)
1372 struct perf_event *event;
1374 update_event_times(leader);
1375 list_for_each_entry(event, &leader->sibling_list, group_entry)
1376 update_event_times(event);
1379 static struct list_head *
1380 ctx_group_list(struct perf_event *event, struct perf_event_context *ctx)
1382 if (event->attr.pinned)
1383 return &ctx->pinned_groups;
1385 return &ctx->flexible_groups;
1389 * Add a event from the lists for its context.
1390 * Must be called with ctx->mutex and ctx->lock held.
1393 list_add_event(struct perf_event *event, struct perf_event_context *ctx)
1395 lockdep_assert_held(&ctx->lock);
1397 WARN_ON_ONCE(event->attach_state & PERF_ATTACH_CONTEXT);
1398 event->attach_state |= PERF_ATTACH_CONTEXT;
1401 * If we're a stand alone event or group leader, we go to the context
1402 * list, group events are kept attached to the group so that
1403 * perf_group_detach can, at all times, locate all siblings.
1405 if (event->group_leader == event) {
1406 struct list_head *list;
1408 if (is_software_event(event))
1409 event->group_flags |= PERF_GROUP_SOFTWARE;
1411 list = ctx_group_list(event, ctx);
1412 list_add_tail(&event->group_entry, list);
1415 if (is_cgroup_event(event))
1418 list_add_rcu(&event->event_entry, &ctx->event_list);
1420 if (event->attr.inherit_stat)
1427 * Initialize event state based on the perf_event_attr::disabled.
1429 static inline void perf_event__state_init(struct perf_event *event)
1431 event->state = event->attr.disabled ? PERF_EVENT_STATE_OFF :
1432 PERF_EVENT_STATE_INACTIVE;
1435 static void __perf_event_read_size(struct perf_event *event, int nr_siblings)
1437 int entry = sizeof(u64); /* value */
1441 if (event->attr.read_format & PERF_FORMAT_TOTAL_TIME_ENABLED)
1442 size += sizeof(u64);
1444 if (event->attr.read_format & PERF_FORMAT_TOTAL_TIME_RUNNING)
1445 size += sizeof(u64);
1447 if (event->attr.read_format & PERF_FORMAT_ID)
1448 entry += sizeof(u64);
1450 if (event->attr.read_format & PERF_FORMAT_GROUP) {
1452 size += sizeof(u64);
1456 event->read_size = size;
1459 static void __perf_event_header_size(struct perf_event *event, u64 sample_type)
1461 struct perf_sample_data *data;
1464 if (sample_type & PERF_SAMPLE_IP)
1465 size += sizeof(data->ip);
1467 if (sample_type & PERF_SAMPLE_ADDR)
1468 size += sizeof(data->addr);
1470 if (sample_type & PERF_SAMPLE_PERIOD)
1471 size += sizeof(data->period);
1473 if (sample_type & PERF_SAMPLE_WEIGHT)
1474 size += sizeof(data->weight);
1476 if (sample_type & PERF_SAMPLE_READ)
1477 size += event->read_size;
1479 if (sample_type & PERF_SAMPLE_DATA_SRC)
1480 size += sizeof(data->data_src.val);
1482 if (sample_type & PERF_SAMPLE_TRANSACTION)
1483 size += sizeof(data->txn);
1485 event->header_size = size;
1489 * Called at perf_event creation and when events are attached/detached from a
1492 static void perf_event__header_size(struct perf_event *event)
1494 __perf_event_read_size(event,
1495 event->group_leader->nr_siblings);
1496 __perf_event_header_size(event, event->attr.sample_type);
1499 static void perf_event__id_header_size(struct perf_event *event)
1501 struct perf_sample_data *data;
1502 u64 sample_type = event->attr.sample_type;
1505 if (sample_type & PERF_SAMPLE_TID)
1506 size += sizeof(data->tid_entry);
1508 if (sample_type & PERF_SAMPLE_TIME)
1509 size += sizeof(data->time);
1511 if (sample_type & PERF_SAMPLE_IDENTIFIER)
1512 size += sizeof(data->id);
1514 if (sample_type & PERF_SAMPLE_ID)
1515 size += sizeof(data->id);
1517 if (sample_type & PERF_SAMPLE_STREAM_ID)
1518 size += sizeof(data->stream_id);
1520 if (sample_type & PERF_SAMPLE_CPU)
1521 size += sizeof(data->cpu_entry);
1523 event->id_header_size = size;
1526 static bool perf_event_validate_size(struct perf_event *event)
1529 * The values computed here will be over-written when we actually
1532 __perf_event_read_size(event, event->group_leader->nr_siblings + 1);
1533 __perf_event_header_size(event, event->attr.sample_type & ~PERF_SAMPLE_READ);
1534 perf_event__id_header_size(event);
1537 * Sum the lot; should not exceed the 64k limit we have on records.
1538 * Conservative limit to allow for callchains and other variable fields.
1540 if (event->read_size + event->header_size +
1541 event->id_header_size + sizeof(struct perf_event_header) >= 16*1024)
1547 static void perf_group_attach(struct perf_event *event)
1549 struct perf_event *group_leader = event->group_leader, *pos;
1552 * We can have double attach due to group movement in perf_event_open.
1554 if (event->attach_state & PERF_ATTACH_GROUP)
1557 event->attach_state |= PERF_ATTACH_GROUP;
1559 if (group_leader == event)
1562 WARN_ON_ONCE(group_leader->ctx != event->ctx);
1564 if (group_leader->group_flags & PERF_GROUP_SOFTWARE &&
1565 !is_software_event(event))
1566 group_leader->group_flags &= ~PERF_GROUP_SOFTWARE;
1568 list_add_tail(&event->group_entry, &group_leader->sibling_list);
1569 group_leader->nr_siblings++;
1571 perf_event__header_size(group_leader);
1573 list_for_each_entry(pos, &group_leader->sibling_list, group_entry)
1574 perf_event__header_size(pos);
1578 * Remove a event from the lists for its context.
1579 * Must be called with ctx->mutex and ctx->lock held.
1582 list_del_event(struct perf_event *event, struct perf_event_context *ctx)
1584 struct perf_cpu_context *cpuctx;
1586 WARN_ON_ONCE(event->ctx != ctx);
1587 lockdep_assert_held(&ctx->lock);
1590 * We can have double detach due to exit/hot-unplug + close.
1592 if (!(event->attach_state & PERF_ATTACH_CONTEXT))
1595 event->attach_state &= ~PERF_ATTACH_CONTEXT;
1597 if (is_cgroup_event(event)) {
1600 * Because cgroup events are always per-cpu events, this will
1601 * always be called from the right CPU.
1603 cpuctx = __get_cpu_context(ctx);
1605 * If there are no more cgroup events then clear cgrp to avoid
1606 * stale pointer in update_cgrp_time_from_cpuctx().
1608 if (!ctx->nr_cgroups)
1609 cpuctx->cgrp = NULL;
1613 if (event->attr.inherit_stat)
1616 list_del_rcu(&event->event_entry);
1618 if (event->group_leader == event)
1619 list_del_init(&event->group_entry);
1621 update_group_times(event);
1624 * If event was in error state, then keep it
1625 * that way, otherwise bogus counts will be
1626 * returned on read(). The only way to get out
1627 * of error state is by explicit re-enabling
1630 if (event->state > PERF_EVENT_STATE_OFF)
1631 event->state = PERF_EVENT_STATE_OFF;
1636 static void perf_group_detach(struct perf_event *event)
1638 struct perf_event *sibling, *tmp;
1639 struct list_head *list = NULL;
1642 * We can have double detach due to exit/hot-unplug + close.
1644 if (!(event->attach_state & PERF_ATTACH_GROUP))
1647 event->attach_state &= ~PERF_ATTACH_GROUP;
1650 * If this is a sibling, remove it from its group.
1652 if (event->group_leader != event) {
1653 list_del_init(&event->group_entry);
1654 event->group_leader->nr_siblings--;
1658 if (!list_empty(&event->group_entry))
1659 list = &event->group_entry;
1662 * If this was a group event with sibling events then
1663 * upgrade the siblings to singleton events by adding them
1664 * to whatever list we are on.
1666 list_for_each_entry_safe(sibling, tmp, &event->sibling_list, group_entry) {
1668 list_move_tail(&sibling->group_entry, list);
1669 sibling->group_leader = sibling;
1671 /* Inherit group flags from the previous leader */
1672 sibling->group_flags = event->group_flags;
1674 WARN_ON_ONCE(sibling->ctx != event->ctx);
1678 perf_event__header_size(event->group_leader);
1680 list_for_each_entry(tmp, &event->group_leader->sibling_list, group_entry)
1681 perf_event__header_size(tmp);
1684 static bool is_orphaned_event(struct perf_event *event)
1686 return event->state == PERF_EVENT_STATE_DEAD;
1689 static inline int __pmu_filter_match(struct perf_event *event)
1691 struct pmu *pmu = event->pmu;
1692 return pmu->filter_match ? pmu->filter_match(event) : 1;
1696 * Check whether we should attempt to schedule an event group based on
1697 * PMU-specific filtering. An event group can consist of HW and SW events,
1698 * potentially with a SW leader, so we must check all the filters, to
1699 * determine whether a group is schedulable:
1701 static inline int pmu_filter_match(struct perf_event *event)
1703 struct perf_event *child;
1705 if (!__pmu_filter_match(event))
1708 list_for_each_entry(child, &event->sibling_list, group_entry) {
1709 if (!__pmu_filter_match(child))
1717 event_filter_match(struct perf_event *event)
1719 return (event->cpu == -1 || event->cpu == smp_processor_id()) &&
1720 perf_cgroup_match(event) && pmu_filter_match(event);
1724 event_sched_out(struct perf_event *event,
1725 struct perf_cpu_context *cpuctx,
1726 struct perf_event_context *ctx)
1728 u64 tstamp = perf_event_time(event);
1731 WARN_ON_ONCE(event->ctx != ctx);
1732 lockdep_assert_held(&ctx->lock);
1735 * An event which could not be activated because of
1736 * filter mismatch still needs to have its timings
1737 * maintained, otherwise bogus information is return
1738 * via read() for time_enabled, time_running:
1740 if (event->state == PERF_EVENT_STATE_INACTIVE &&
1741 !event_filter_match(event)) {
1742 delta = tstamp - event->tstamp_stopped;
1743 event->tstamp_running += delta;
1744 event->tstamp_stopped = tstamp;
1747 if (event->state != PERF_EVENT_STATE_ACTIVE)
1750 perf_pmu_disable(event->pmu);
1752 event->tstamp_stopped = tstamp;
1753 event->pmu->del(event, 0);
1755 event->state = PERF_EVENT_STATE_INACTIVE;
1756 if (event->pending_disable) {
1757 event->pending_disable = 0;
1758 event->state = PERF_EVENT_STATE_OFF;
1761 if (!is_software_event(event))
1762 cpuctx->active_oncpu--;
1763 if (!--ctx->nr_active)
1764 perf_event_ctx_deactivate(ctx);
1765 if (event->attr.freq && event->attr.sample_freq)
1767 if (event->attr.exclusive || !cpuctx->active_oncpu)
1768 cpuctx->exclusive = 0;
1770 perf_pmu_enable(event->pmu);
1774 group_sched_out(struct perf_event *group_event,
1775 struct perf_cpu_context *cpuctx,
1776 struct perf_event_context *ctx)
1778 struct perf_event *event;
1779 int state = group_event->state;
1781 event_sched_out(group_event, cpuctx, ctx);
1784 * Schedule out siblings (if any):
1786 list_for_each_entry(event, &group_event->sibling_list, group_entry)
1787 event_sched_out(event, cpuctx, ctx);
1789 if (state == PERF_EVENT_STATE_ACTIVE && group_event->attr.exclusive)
1790 cpuctx->exclusive = 0;
1793 #define DETACH_GROUP 0x01UL
1796 * Cross CPU call to remove a performance event
1798 * We disable the event on the hardware level first. After that we
1799 * remove it from the context list.
1802 __perf_remove_from_context(struct perf_event *event,
1803 struct perf_cpu_context *cpuctx,
1804 struct perf_event_context *ctx,
1807 unsigned long flags = (unsigned long)info;
1809 event_sched_out(event, cpuctx, ctx);
1810 if (flags & DETACH_GROUP)
1811 perf_group_detach(event);
1812 list_del_event(event, ctx);
1814 if (!ctx->nr_events && ctx->is_active) {
1817 WARN_ON_ONCE(cpuctx->task_ctx != ctx);
1818 cpuctx->task_ctx = NULL;
1824 * Remove the event from a task's (or a CPU's) list of events.
1826 * If event->ctx is a cloned context, callers must make sure that
1827 * every task struct that event->ctx->task could possibly point to
1828 * remains valid. This is OK when called from perf_release since
1829 * that only calls us on the top-level context, which can't be a clone.
1830 * When called from perf_event_exit_task, it's OK because the
1831 * context has been detached from its task.
1833 static void perf_remove_from_context(struct perf_event *event, unsigned long flags)
1835 lockdep_assert_held(&event->ctx->mutex);
1837 event_function_call(event, __perf_remove_from_context, (void *)flags);
1841 * Cross CPU call to disable a performance event
1843 static void __perf_event_disable(struct perf_event *event,
1844 struct perf_cpu_context *cpuctx,
1845 struct perf_event_context *ctx,
1848 if (event->state < PERF_EVENT_STATE_INACTIVE)
1851 update_context_time(ctx);
1852 update_cgrp_time_from_event(event);
1853 update_group_times(event);
1854 if (event == event->group_leader)
1855 group_sched_out(event, cpuctx, ctx);
1857 event_sched_out(event, cpuctx, ctx);
1858 event->state = PERF_EVENT_STATE_OFF;
1864 * If event->ctx is a cloned context, callers must make sure that
1865 * every task struct that event->ctx->task could possibly point to
1866 * remains valid. This condition is satisifed when called through
1867 * perf_event_for_each_child or perf_event_for_each because they
1868 * hold the top-level event's child_mutex, so any descendant that
1869 * goes to exit will block in perf_event_exit_event().
1871 * When called from perf_pending_event it's OK because event->ctx
1872 * is the current context on this CPU and preemption is disabled,
1873 * hence we can't get into perf_event_task_sched_out for this context.
1875 static void _perf_event_disable(struct perf_event *event)
1877 struct perf_event_context *ctx = event->ctx;
1879 raw_spin_lock_irq(&ctx->lock);
1880 if (event->state <= PERF_EVENT_STATE_OFF) {
1881 raw_spin_unlock_irq(&ctx->lock);
1884 raw_spin_unlock_irq(&ctx->lock);
1886 event_function_call(event, __perf_event_disable, NULL);
1889 void perf_event_disable_local(struct perf_event *event)
1891 event_function_local(event, __perf_event_disable, NULL);
1895 * Strictly speaking kernel users cannot create groups and therefore this
1896 * interface does not need the perf_event_ctx_lock() magic.
1898 void perf_event_disable(struct perf_event *event)
1900 struct perf_event_context *ctx;
1902 ctx = perf_event_ctx_lock(event);
1903 _perf_event_disable(event);
1904 perf_event_ctx_unlock(event, ctx);
1906 EXPORT_SYMBOL_GPL(perf_event_disable);
1908 static void perf_set_shadow_time(struct perf_event *event,
1909 struct perf_event_context *ctx,
1913 * use the correct time source for the time snapshot
1915 * We could get by without this by leveraging the
1916 * fact that to get to this function, the caller
1917 * has most likely already called update_context_time()
1918 * and update_cgrp_time_xx() and thus both timestamp
1919 * are identical (or very close). Given that tstamp is,
1920 * already adjusted for cgroup, we could say that:
1921 * tstamp - ctx->timestamp
1923 * tstamp - cgrp->timestamp.
1925 * Then, in perf_output_read(), the calculation would
1926 * work with no changes because:
1927 * - event is guaranteed scheduled in
1928 * - no scheduled out in between
1929 * - thus the timestamp would be the same
1931 * But this is a bit hairy.
1933 * So instead, we have an explicit cgroup call to remain
1934 * within the time time source all along. We believe it
1935 * is cleaner and simpler to understand.
1937 if (is_cgroup_event(event))
1938 perf_cgroup_set_shadow_time(event, tstamp);
1940 event->shadow_ctx_time = tstamp - ctx->timestamp;
1943 #define MAX_INTERRUPTS (~0ULL)
1945 static void perf_log_throttle(struct perf_event *event, int enable);
1946 static void perf_log_itrace_start(struct perf_event *event);
1949 event_sched_in(struct perf_event *event,
1950 struct perf_cpu_context *cpuctx,
1951 struct perf_event_context *ctx)
1953 u64 tstamp = perf_event_time(event);
1956 lockdep_assert_held(&ctx->lock);
1958 if (event->state <= PERF_EVENT_STATE_OFF)
1961 WRITE_ONCE(event->oncpu, smp_processor_id());
1963 * Order event::oncpu write to happen before the ACTIVE state
1967 WRITE_ONCE(event->state, PERF_EVENT_STATE_ACTIVE);
1970 * Unthrottle events, since we scheduled we might have missed several
1971 * ticks already, also for a heavily scheduling task there is little
1972 * guarantee it'll get a tick in a timely manner.
1974 if (unlikely(event->hw.interrupts == MAX_INTERRUPTS)) {
1975 perf_log_throttle(event, 1);
1976 event->hw.interrupts = 0;
1980 * The new state must be visible before we turn it on in the hardware:
1984 perf_pmu_disable(event->pmu);
1986 perf_set_shadow_time(event, ctx, tstamp);
1988 perf_log_itrace_start(event);
1990 if (event->pmu->add(event, PERF_EF_START)) {
1991 event->state = PERF_EVENT_STATE_INACTIVE;
1997 event->tstamp_running += tstamp - event->tstamp_stopped;
1999 if (!is_software_event(event))
2000 cpuctx->active_oncpu++;
2001 if (!ctx->nr_active++)
2002 perf_event_ctx_activate(ctx);
2003 if (event->attr.freq && event->attr.sample_freq)
2006 if (event->attr.exclusive)
2007 cpuctx->exclusive = 1;
2010 perf_pmu_enable(event->pmu);
2016 group_sched_in(struct perf_event *group_event,
2017 struct perf_cpu_context *cpuctx,
2018 struct perf_event_context *ctx)
2020 struct perf_event *event, *partial_group = NULL;
2021 struct pmu *pmu = ctx->pmu;
2022 u64 now = ctx->time;
2023 bool simulate = false;
2025 if (group_event->state == PERF_EVENT_STATE_OFF)
2028 pmu->start_txn(pmu, PERF_PMU_TXN_ADD);
2030 if (event_sched_in(group_event, cpuctx, ctx)) {
2031 pmu->cancel_txn(pmu);
2032 perf_mux_hrtimer_restart(cpuctx);
2037 * Schedule in siblings as one group (if any):
2039 list_for_each_entry(event, &group_event->sibling_list, group_entry) {
2040 if (event_sched_in(event, cpuctx, ctx)) {
2041 partial_group = event;
2046 if (!pmu->commit_txn(pmu))
2051 * Groups can be scheduled in as one unit only, so undo any
2052 * partial group before returning:
2053 * The events up to the failed event are scheduled out normally,
2054 * tstamp_stopped will be updated.
2056 * The failed events and the remaining siblings need to have
2057 * their timings updated as if they had gone thru event_sched_in()
2058 * and event_sched_out(). This is required to get consistent timings
2059 * across the group. This also takes care of the case where the group
2060 * could never be scheduled by ensuring tstamp_stopped is set to mark
2061 * the time the event was actually stopped, such that time delta
2062 * calculation in update_event_times() is correct.
2064 list_for_each_entry(event, &group_event->sibling_list, group_entry) {
2065 if (event == partial_group)
2069 event->tstamp_running += now - event->tstamp_stopped;
2070 event->tstamp_stopped = now;
2072 event_sched_out(event, cpuctx, ctx);
2075 event_sched_out(group_event, cpuctx, ctx);
2077 pmu->cancel_txn(pmu);
2079 perf_mux_hrtimer_restart(cpuctx);
2085 * Work out whether we can put this event group on the CPU now.
2087 static int group_can_go_on(struct perf_event *event,
2088 struct perf_cpu_context *cpuctx,
2092 * Groups consisting entirely of software events can always go on.
2094 if (event->group_flags & PERF_GROUP_SOFTWARE)
2097 * If an exclusive group is already on, no other hardware
2100 if (cpuctx->exclusive)
2103 * If this group is exclusive and there are already
2104 * events on the CPU, it can't go on.
2106 if (event->attr.exclusive && cpuctx->active_oncpu)
2109 * Otherwise, try to add it if all previous groups were able
2115 static void add_event_to_ctx(struct perf_event *event,
2116 struct perf_event_context *ctx)
2118 u64 tstamp = perf_event_time(event);
2120 list_add_event(event, ctx);
2121 perf_group_attach(event);
2122 event->tstamp_enabled = tstamp;
2123 event->tstamp_running = tstamp;
2124 event->tstamp_stopped = tstamp;
2127 static void ctx_sched_out(struct perf_event_context *ctx,
2128 struct perf_cpu_context *cpuctx,
2129 enum event_type_t event_type);
2131 ctx_sched_in(struct perf_event_context *ctx,
2132 struct perf_cpu_context *cpuctx,
2133 enum event_type_t event_type,
2134 struct task_struct *task);
2136 static void task_ctx_sched_out(struct perf_cpu_context *cpuctx,
2137 struct perf_event_context *ctx)
2139 if (!cpuctx->task_ctx)
2142 if (WARN_ON_ONCE(ctx != cpuctx->task_ctx))
2145 ctx_sched_out(ctx, cpuctx, EVENT_ALL);
2148 static void perf_event_sched_in(struct perf_cpu_context *cpuctx,
2149 struct perf_event_context *ctx,
2150 struct task_struct *task)
2152 cpu_ctx_sched_in(cpuctx, EVENT_PINNED, task);
2154 ctx_sched_in(ctx, cpuctx, EVENT_PINNED, task);
2155 cpu_ctx_sched_in(cpuctx, EVENT_FLEXIBLE, task);
2157 ctx_sched_in(ctx, cpuctx, EVENT_FLEXIBLE, task);
2160 static void ctx_resched(struct perf_cpu_context *cpuctx,
2161 struct perf_event_context *task_ctx)
2163 perf_pmu_disable(cpuctx->ctx.pmu);
2165 task_ctx_sched_out(cpuctx, task_ctx);
2166 cpu_ctx_sched_out(cpuctx, EVENT_ALL);
2167 perf_event_sched_in(cpuctx, task_ctx, current);
2168 perf_pmu_enable(cpuctx->ctx.pmu);
2172 * Cross CPU call to install and enable a performance event
2174 * Very similar to remote_function() + event_function() but cannot assume that
2175 * things like ctx->is_active and cpuctx->task_ctx are set.
2177 static int __perf_install_in_context(void *info)
2179 struct perf_event *event = info;
2180 struct perf_event_context *ctx = event->ctx;
2181 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
2182 struct perf_event_context *task_ctx = cpuctx->task_ctx;
2183 bool activate = true;
2186 raw_spin_lock(&cpuctx->ctx.lock);
2188 raw_spin_lock(&ctx->lock);
2191 /* If we're on the wrong CPU, try again */
2192 if (task_cpu(ctx->task) != smp_processor_id()) {
2198 * If we're on the right CPU, see if the task we target is
2199 * current, if not we don't have to activate the ctx, a future
2200 * context switch will do that for us.
2202 if (ctx->task != current)
2205 WARN_ON_ONCE(cpuctx->task_ctx && cpuctx->task_ctx != ctx);
2207 } else if (task_ctx) {
2208 raw_spin_lock(&task_ctx->lock);
2212 ctx_sched_out(ctx, cpuctx, EVENT_TIME);
2213 add_event_to_ctx(event, ctx);
2214 ctx_resched(cpuctx, task_ctx);
2216 add_event_to_ctx(event, ctx);
2220 perf_ctx_unlock(cpuctx, task_ctx);
2226 * Attach a performance event to a context.
2228 * Very similar to event_function_call, see comment there.
2231 perf_install_in_context(struct perf_event_context *ctx,
2232 struct perf_event *event,
2235 struct task_struct *task = READ_ONCE(ctx->task);
2237 lockdep_assert_held(&ctx->mutex);
2239 if (event->cpu != -1)
2243 * Ensures that if we can observe event->ctx, both the event and ctx
2244 * will be 'complete'. See perf_iterate_sb_cpu().
2246 smp_store_release(&event->ctx, ctx);
2249 cpu_function_call(cpu, __perf_install_in_context, event);
2254 * Should not happen, we validate the ctx is still alive before calling.
2256 if (WARN_ON_ONCE(task == TASK_TOMBSTONE))
2260 * Installing events is tricky because we cannot rely on ctx->is_active
2261 * to be set in case this is the nr_events 0 -> 1 transition.
2265 * Cannot use task_function_call() because we need to run on the task's
2266 * CPU regardless of whether its current or not.
2268 if (!cpu_function_call(task_cpu(task), __perf_install_in_context, event))
2271 raw_spin_lock_irq(&ctx->lock);
2273 if (WARN_ON_ONCE(task == TASK_TOMBSTONE)) {
2275 * Cannot happen because we already checked above (which also
2276 * cannot happen), and we hold ctx->mutex, which serializes us
2277 * against perf_event_exit_task_context().
2279 raw_spin_unlock_irq(&ctx->lock);
2282 raw_spin_unlock_irq(&ctx->lock);
2284 * Since !ctx->is_active doesn't mean anything, we must IPI
2291 * Put a event into inactive state and update time fields.
2292 * Enabling the leader of a group effectively enables all
2293 * the group members that aren't explicitly disabled, so we
2294 * have to update their ->tstamp_enabled also.
2295 * Note: this works for group members as well as group leaders
2296 * since the non-leader members' sibling_lists will be empty.
2298 static void __perf_event_mark_enabled(struct perf_event *event)
2300 struct perf_event *sub;
2301 u64 tstamp = perf_event_time(event);
2303 event->state = PERF_EVENT_STATE_INACTIVE;
2304 event->tstamp_enabled = tstamp - event->total_time_enabled;
2305 list_for_each_entry(sub, &event->sibling_list, group_entry) {
2306 if (sub->state >= PERF_EVENT_STATE_INACTIVE)
2307 sub->tstamp_enabled = tstamp - sub->total_time_enabled;
2312 * Cross CPU call to enable a performance event
2314 static void __perf_event_enable(struct perf_event *event,
2315 struct perf_cpu_context *cpuctx,
2316 struct perf_event_context *ctx,
2319 struct perf_event *leader = event->group_leader;
2320 struct perf_event_context *task_ctx;
2322 if (event->state >= PERF_EVENT_STATE_INACTIVE ||
2323 event->state <= PERF_EVENT_STATE_ERROR)
2327 ctx_sched_out(ctx, cpuctx, EVENT_TIME);
2329 __perf_event_mark_enabled(event);
2331 if (!ctx->is_active)
2334 if (!event_filter_match(event)) {
2335 if (is_cgroup_event(event))
2336 perf_cgroup_defer_enabled(event);
2337 ctx_sched_in(ctx, cpuctx, EVENT_TIME, current);
2342 * If the event is in a group and isn't the group leader,
2343 * then don't put it on unless the group is on.
2345 if (leader != event && leader->state != PERF_EVENT_STATE_ACTIVE) {
2346 ctx_sched_in(ctx, cpuctx, EVENT_TIME, current);
2350 task_ctx = cpuctx->task_ctx;
2352 WARN_ON_ONCE(task_ctx != ctx);
2354 ctx_resched(cpuctx, task_ctx);
2360 * If event->ctx is a cloned context, callers must make sure that
2361 * every task struct that event->ctx->task could possibly point to
2362 * remains valid. This condition is satisfied when called through
2363 * perf_event_for_each_child or perf_event_for_each as described
2364 * for perf_event_disable.
2366 static void _perf_event_enable(struct perf_event *event)
2368 struct perf_event_context *ctx = event->ctx;
2370 raw_spin_lock_irq(&ctx->lock);
2371 if (event->state >= PERF_EVENT_STATE_INACTIVE ||
2372 event->state < PERF_EVENT_STATE_ERROR) {
2373 raw_spin_unlock_irq(&ctx->lock);
2378 * If the event is in error state, clear that first.
2380 * That way, if we see the event in error state below, we know that it
2381 * has gone back into error state, as distinct from the task having
2382 * been scheduled away before the cross-call arrived.
2384 if (event->state == PERF_EVENT_STATE_ERROR)
2385 event->state = PERF_EVENT_STATE_OFF;
2386 raw_spin_unlock_irq(&ctx->lock);
2388 event_function_call(event, __perf_event_enable, NULL);
2392 * See perf_event_disable();
2394 void perf_event_enable(struct perf_event *event)
2396 struct perf_event_context *ctx;
2398 ctx = perf_event_ctx_lock(event);
2399 _perf_event_enable(event);
2400 perf_event_ctx_unlock(event, ctx);
2402 EXPORT_SYMBOL_GPL(perf_event_enable);
2404 struct stop_event_data {
2405 struct perf_event *event;
2406 unsigned int restart;
2409 static int __perf_event_stop(void *info)
2411 struct stop_event_data *sd = info;
2412 struct perf_event *event = sd->event;
2414 /* if it's already INACTIVE, do nothing */
2415 if (READ_ONCE(event->state) != PERF_EVENT_STATE_ACTIVE)
2418 /* matches smp_wmb() in event_sched_in() */
2422 * There is a window with interrupts enabled before we get here,
2423 * so we need to check again lest we try to stop another CPU's event.
2425 if (READ_ONCE(event->oncpu) != smp_processor_id())
2428 event->pmu->stop(event, PERF_EF_UPDATE);
2431 * May race with the actual stop (through perf_pmu_output_stop()),
2432 * but it is only used for events with AUX ring buffer, and such
2433 * events will refuse to restart because of rb::aux_mmap_count==0,
2434 * see comments in perf_aux_output_begin().
2436 * Since this is happening on a event-local CPU, no trace is lost
2440 event->pmu->start(event, PERF_EF_START);
2445 static int perf_event_restart(struct perf_event *event)
2447 struct stop_event_data sd = {
2454 if (READ_ONCE(event->state) != PERF_EVENT_STATE_ACTIVE)
2457 /* matches smp_wmb() in event_sched_in() */
2461 * We only want to restart ACTIVE events, so if the event goes
2462 * inactive here (event->oncpu==-1), there's nothing more to do;
2463 * fall through with ret==-ENXIO.
2465 ret = cpu_function_call(READ_ONCE(event->oncpu),
2466 __perf_event_stop, &sd);
2467 } while (ret == -EAGAIN);
2473 * In order to contain the amount of racy and tricky in the address filter
2474 * configuration management, it is a two part process:
2476 * (p1) when userspace mappings change as a result of (1) or (2) or (3) below,
2477 * we update the addresses of corresponding vmas in
2478 * event::addr_filters_offs array and bump the event::addr_filters_gen;
2479 * (p2) when an event is scheduled in (pmu::add), it calls
2480 * perf_event_addr_filters_sync() which calls pmu::addr_filters_sync()
2481 * if the generation has changed since the previous call.
2483 * If (p1) happens while the event is active, we restart it to force (p2).
2485 * (1) perf_addr_filters_apply(): adjusting filters' offsets based on
2486 * pre-existing mappings, called once when new filters arrive via SET_FILTER
2488 * (2) perf_addr_filters_adjust(): adjusting filters' offsets based on newly
2489 * registered mapping, called for every new mmap(), with mm::mmap_sem down
2491 * (3) perf_event_addr_filters_exec(): clearing filters' offsets in the process
2494 void perf_event_addr_filters_sync(struct perf_event *event)
2496 struct perf_addr_filters_head *ifh = perf_event_addr_filters(event);
2498 if (!has_addr_filter(event))
2501 raw_spin_lock(&ifh->lock);
2502 if (event->addr_filters_gen != event->hw.addr_filters_gen) {
2503 event->pmu->addr_filters_sync(event);
2504 event->hw.addr_filters_gen = event->addr_filters_gen;
2506 raw_spin_unlock(&ifh->lock);
2508 EXPORT_SYMBOL_GPL(perf_event_addr_filters_sync);
2510 static int _perf_event_refresh(struct perf_event *event, int refresh)
2513 * not supported on inherited events
2515 if (event->attr.inherit || !is_sampling_event(event))
2518 atomic_add(refresh, &event->event_limit);
2519 _perf_event_enable(event);
2525 * See perf_event_disable()
2527 int perf_event_refresh(struct perf_event *event, int refresh)
2529 struct perf_event_context *ctx;
2532 ctx = perf_event_ctx_lock(event);
2533 ret = _perf_event_refresh(event, refresh);
2534 perf_event_ctx_unlock(event, ctx);
2538 EXPORT_SYMBOL_GPL(perf_event_refresh);
2540 static void ctx_sched_out(struct perf_event_context *ctx,
2541 struct perf_cpu_context *cpuctx,
2542 enum event_type_t event_type)
2544 int is_active = ctx->is_active;
2545 struct perf_event *event;
2547 lockdep_assert_held(&ctx->lock);
2549 if (likely(!ctx->nr_events)) {
2551 * See __perf_remove_from_context().
2553 WARN_ON_ONCE(ctx->is_active);
2555 WARN_ON_ONCE(cpuctx->task_ctx);
2559 ctx->is_active &= ~event_type;
2560 if (!(ctx->is_active & EVENT_ALL))
2564 WARN_ON_ONCE(cpuctx->task_ctx != ctx);
2565 if (!ctx->is_active)
2566 cpuctx->task_ctx = NULL;
2570 * Always update time if it was set; not only when it changes.
2571 * Otherwise we can 'forget' to update time for any but the last
2572 * context we sched out. For example:
2574 * ctx_sched_out(.event_type = EVENT_FLEXIBLE)
2575 * ctx_sched_out(.event_type = EVENT_PINNED)
2577 * would only update time for the pinned events.
2579 if (is_active & EVENT_TIME) {
2580 /* update (and stop) ctx time */
2581 update_context_time(ctx);
2582 update_cgrp_time_from_cpuctx(cpuctx);
2585 is_active ^= ctx->is_active; /* changed bits */
2587 if (!ctx->nr_active || !(is_active & EVENT_ALL))
2590 perf_pmu_disable(ctx->pmu);
2591 if (is_active & EVENT_PINNED) {
2592 list_for_each_entry(event, &ctx->pinned_groups, group_entry)
2593 group_sched_out(event, cpuctx, ctx);
2596 if (is_active & EVENT_FLEXIBLE) {
2597 list_for_each_entry(event, &ctx->flexible_groups, group_entry)
2598 group_sched_out(event, cpuctx, ctx);
2600 perf_pmu_enable(ctx->pmu);
2604 * Test whether two contexts are equivalent, i.e. whether they have both been
2605 * cloned from the same version of the same context.
2607 * Equivalence is measured using a generation number in the context that is
2608 * incremented on each modification to it; see unclone_ctx(), list_add_event()
2609 * and list_del_event().
2611 static int context_equiv(struct perf_event_context *ctx1,
2612 struct perf_event_context *ctx2)
2614 lockdep_assert_held(&ctx1->lock);
2615 lockdep_assert_held(&ctx2->lock);
2617 /* Pinning disables the swap optimization */
2618 if (ctx1->pin_count || ctx2->pin_count)
2621 /* If ctx1 is the parent of ctx2 */
2622 if (ctx1 == ctx2->parent_ctx && ctx1->generation == ctx2->parent_gen)
2625 /* If ctx2 is the parent of ctx1 */
2626 if (ctx1->parent_ctx == ctx2 && ctx1->parent_gen == ctx2->generation)
2630 * If ctx1 and ctx2 have the same parent; we flatten the parent
2631 * hierarchy, see perf_event_init_context().
2633 if (ctx1->parent_ctx && ctx1->parent_ctx == ctx2->parent_ctx &&
2634 ctx1->parent_gen == ctx2->parent_gen)
2641 static void __perf_event_sync_stat(struct perf_event *event,
2642 struct perf_event *next_event)
2646 if (!event->attr.inherit_stat)
2650 * Update the event value, we cannot use perf_event_read()
2651 * because we're in the middle of a context switch and have IRQs
2652 * disabled, which upsets smp_call_function_single(), however
2653 * we know the event must be on the current CPU, therefore we
2654 * don't need to use it.
2656 switch (event->state) {
2657 case PERF_EVENT_STATE_ACTIVE:
2658 event->pmu->read(event);
2661 case PERF_EVENT_STATE_INACTIVE:
2662 update_event_times(event);
2670 * In order to keep per-task stats reliable we need to flip the event
2671 * values when we flip the contexts.
2673 value = local64_read(&next_event->count);
2674 value = local64_xchg(&event->count, value);
2675 local64_set(&next_event->count, value);
2677 swap(event->total_time_enabled, next_event->total_time_enabled);
2678 swap(event->total_time_running, next_event->total_time_running);
2681 * Since we swizzled the values, update the user visible data too.
2683 perf_event_update_userpage(event);
2684 perf_event_update_userpage(next_event);
2687 static void perf_event_sync_stat(struct perf_event_context *ctx,
2688 struct perf_event_context *next_ctx)
2690 struct perf_event *event, *next_event;
2695 update_context_time(ctx);
2697 event = list_first_entry(&ctx->event_list,
2698 struct perf_event, event_entry);
2700 next_event = list_first_entry(&next_ctx->event_list,
2701 struct perf_event, event_entry);
2703 while (&event->event_entry != &ctx->event_list &&
2704 &next_event->event_entry != &next_ctx->event_list) {
2706 __perf_event_sync_stat(event, next_event);
2708 event = list_next_entry(event, event_entry);
2709 next_event = list_next_entry(next_event, event_entry);
2713 static void perf_event_context_sched_out(struct task_struct *task, int ctxn,
2714 struct task_struct *next)
2716 struct perf_event_context *ctx = task->perf_event_ctxp[ctxn];
2717 struct perf_event_context *next_ctx;
2718 struct perf_event_context *parent, *next_parent;
2719 struct perf_cpu_context *cpuctx;
2725 cpuctx = __get_cpu_context(ctx);
2726 if (!cpuctx->task_ctx)
2730 next_ctx = next->perf_event_ctxp[ctxn];
2734 parent = rcu_dereference(ctx->parent_ctx);
2735 next_parent = rcu_dereference(next_ctx->parent_ctx);
2737 /* If neither context have a parent context; they cannot be clones. */
2738 if (!parent && !next_parent)
2741 if (next_parent == ctx || next_ctx == parent || next_parent == parent) {
2743 * Looks like the two contexts are clones, so we might be
2744 * able to optimize the context switch. We lock both
2745 * contexts and check that they are clones under the
2746 * lock (including re-checking that neither has been
2747 * uncloned in the meantime). It doesn't matter which
2748 * order we take the locks because no other cpu could
2749 * be trying to lock both of these tasks.
2751 raw_spin_lock(&ctx->lock);
2752 raw_spin_lock_nested(&next_ctx->lock, SINGLE_DEPTH_NESTING);
2753 if (context_equiv(ctx, next_ctx)) {
2754 WRITE_ONCE(ctx->task, next);
2755 WRITE_ONCE(next_ctx->task, task);
2757 swap(ctx->task_ctx_data, next_ctx->task_ctx_data);
2760 * RCU_INIT_POINTER here is safe because we've not
2761 * modified the ctx and the above modification of
2762 * ctx->task and ctx->task_ctx_data are immaterial
2763 * since those values are always verified under
2764 * ctx->lock which we're now holding.
2766 RCU_INIT_POINTER(task->perf_event_ctxp[ctxn], next_ctx);
2767 RCU_INIT_POINTER(next->perf_event_ctxp[ctxn], ctx);
2771 perf_event_sync_stat(ctx, next_ctx);
2773 raw_spin_unlock(&next_ctx->lock);
2774 raw_spin_unlock(&ctx->lock);
2780 raw_spin_lock(&ctx->lock);
2781 task_ctx_sched_out(cpuctx, ctx);
2782 raw_spin_unlock(&ctx->lock);
2786 void perf_sched_cb_dec(struct pmu *pmu)
2788 this_cpu_dec(perf_sched_cb_usages);
2791 void perf_sched_cb_inc(struct pmu *pmu)
2793 this_cpu_inc(perf_sched_cb_usages);
2797 * This function provides the context switch callback to the lower code
2798 * layer. It is invoked ONLY when the context switch callback is enabled.
2800 static void perf_pmu_sched_task(struct task_struct *prev,
2801 struct task_struct *next,
2804 struct perf_cpu_context *cpuctx;
2806 unsigned long flags;
2811 local_irq_save(flags);
2815 list_for_each_entry_rcu(pmu, &pmus, entry) {
2816 if (pmu->sched_task) {
2817 cpuctx = this_cpu_ptr(pmu->pmu_cpu_context);
2819 perf_ctx_lock(cpuctx, cpuctx->task_ctx);
2821 perf_pmu_disable(pmu);
2823 pmu->sched_task(cpuctx->task_ctx, sched_in);
2825 perf_pmu_enable(pmu);
2827 perf_ctx_unlock(cpuctx, cpuctx->task_ctx);
2833 local_irq_restore(flags);
2836 static void perf_event_switch(struct task_struct *task,
2837 struct task_struct *next_prev, bool sched_in);
2839 #define for_each_task_context_nr(ctxn) \
2840 for ((ctxn) = 0; (ctxn) < perf_nr_task_contexts; (ctxn)++)
2843 * Called from scheduler to remove the events of the current task,
2844 * with interrupts disabled.
2846 * We stop each event and update the event value in event->count.
2848 * This does not protect us against NMI, but disable()
2849 * sets the disabled bit in the control field of event _before_
2850 * accessing the event control register. If a NMI hits, then it will
2851 * not restart the event.
2853 void __perf_event_task_sched_out(struct task_struct *task,
2854 struct task_struct *next)
2858 if (__this_cpu_read(perf_sched_cb_usages))
2859 perf_pmu_sched_task(task, next, false);
2861 if (atomic_read(&nr_switch_events))
2862 perf_event_switch(task, next, false);
2864 for_each_task_context_nr(ctxn)
2865 perf_event_context_sched_out(task, ctxn, next);
2868 * if cgroup events exist on this CPU, then we need
2869 * to check if we have to switch out PMU state.
2870 * cgroup event are system-wide mode only
2872 if (atomic_read(this_cpu_ptr(&perf_cgroup_events)))
2873 perf_cgroup_sched_out(task, next);
2877 * Called with IRQs disabled
2879 static void cpu_ctx_sched_out(struct perf_cpu_context *cpuctx,
2880 enum event_type_t event_type)
2882 ctx_sched_out(&cpuctx->ctx, cpuctx, event_type);
2886 ctx_pinned_sched_in(struct perf_event_context *ctx,
2887 struct perf_cpu_context *cpuctx)
2889 struct perf_event *event;
2891 list_for_each_entry(event, &ctx->pinned_groups, group_entry) {
2892 if (event->state <= PERF_EVENT_STATE_OFF)
2894 if (!event_filter_match(event))
2897 /* may need to reset tstamp_enabled */
2898 if (is_cgroup_event(event))
2899 perf_cgroup_mark_enabled(event, ctx);
2901 if (group_can_go_on(event, cpuctx, 1))
2902 group_sched_in(event, cpuctx, ctx);
2905 * If this pinned group hasn't been scheduled,
2906 * put it in error state.
2908 if (event->state == PERF_EVENT_STATE_INACTIVE) {
2909 update_group_times(event);
2910 event->state = PERF_EVENT_STATE_ERROR;
2916 ctx_flexible_sched_in(struct perf_event_context *ctx,
2917 struct perf_cpu_context *cpuctx)
2919 struct perf_event *event;
2922 list_for_each_entry(event, &ctx->flexible_groups, group_entry) {
2923 /* Ignore events in OFF or ERROR state */
2924 if (event->state <= PERF_EVENT_STATE_OFF)
2927 * Listen to the 'cpu' scheduling filter constraint
2930 if (!event_filter_match(event))
2933 /* may need to reset tstamp_enabled */
2934 if (is_cgroup_event(event))
2935 perf_cgroup_mark_enabled(event, ctx);
2937 if (group_can_go_on(event, cpuctx, can_add_hw)) {
2938 if (group_sched_in(event, cpuctx, ctx))
2945 ctx_sched_in(struct perf_event_context *ctx,
2946 struct perf_cpu_context *cpuctx,
2947 enum event_type_t event_type,
2948 struct task_struct *task)
2950 int is_active = ctx->is_active;
2953 lockdep_assert_held(&ctx->lock);
2955 if (likely(!ctx->nr_events))
2958 ctx->is_active |= (event_type | EVENT_TIME);
2961 cpuctx->task_ctx = ctx;
2963 WARN_ON_ONCE(cpuctx->task_ctx != ctx);
2966 is_active ^= ctx->is_active; /* changed bits */
2968 if (is_active & EVENT_TIME) {
2969 /* start ctx time */
2971 ctx->timestamp = now;
2972 perf_cgroup_set_timestamp(task, ctx);
2976 * First go through the list and put on any pinned groups
2977 * in order to give them the best chance of going on.
2979 if (is_active & EVENT_PINNED)
2980 ctx_pinned_sched_in(ctx, cpuctx);
2982 /* Then walk through the lower prio flexible groups */
2983 if (is_active & EVENT_FLEXIBLE)
2984 ctx_flexible_sched_in(ctx, cpuctx);
2987 static void cpu_ctx_sched_in(struct perf_cpu_context *cpuctx,
2988 enum event_type_t event_type,
2989 struct task_struct *task)
2991 struct perf_event_context *ctx = &cpuctx->ctx;
2993 ctx_sched_in(ctx, cpuctx, event_type, task);
2996 static void perf_event_context_sched_in(struct perf_event_context *ctx,
2997 struct task_struct *task)
2999 struct perf_cpu_context *cpuctx;
3001 cpuctx = __get_cpu_context(ctx);
3002 if (cpuctx->task_ctx == ctx)
3005 perf_ctx_lock(cpuctx, ctx);
3006 perf_pmu_disable(ctx->pmu);
3008 * We want to keep the following priority order:
3009 * cpu pinned (that don't need to move), task pinned,
3010 * cpu flexible, task flexible.
3012 cpu_ctx_sched_out(cpuctx, EVENT_FLEXIBLE);
3013 perf_event_sched_in(cpuctx, ctx, task);
3014 perf_pmu_enable(ctx->pmu);
3015 perf_ctx_unlock(cpuctx, ctx);
3019 * Called from scheduler to add the events of the current task
3020 * with interrupts disabled.
3022 * We restore the event value and then enable it.
3024 * This does not protect us against NMI, but enable()
3025 * sets the enabled bit in the control field of event _before_
3026 * accessing the event control register. If a NMI hits, then it will
3027 * keep the event running.
3029 void __perf_event_task_sched_in(struct task_struct *prev,
3030 struct task_struct *task)
3032 struct perf_event_context *ctx;
3036 * If cgroup events exist on this CPU, then we need to check if we have
3037 * to switch in PMU state; cgroup event are system-wide mode only.
3039 * Since cgroup events are CPU events, we must schedule these in before
3040 * we schedule in the task events.
3042 if (atomic_read(this_cpu_ptr(&perf_cgroup_events)))
3043 perf_cgroup_sched_in(prev, task);
3045 for_each_task_context_nr(ctxn) {
3046 ctx = task->perf_event_ctxp[ctxn];
3050 perf_event_context_sched_in(ctx, task);
3053 if (atomic_read(&nr_switch_events))
3054 perf_event_switch(task, prev, true);
3056 if (__this_cpu_read(perf_sched_cb_usages))
3057 perf_pmu_sched_task(prev, task, true);
3060 static u64 perf_calculate_period(struct perf_event *event, u64 nsec, u64 count)
3062 u64 frequency = event->attr.sample_freq;
3063 u64 sec = NSEC_PER_SEC;
3064 u64 divisor, dividend;
3066 int count_fls, nsec_fls, frequency_fls, sec_fls;
3068 count_fls = fls64(count);
3069 nsec_fls = fls64(nsec);
3070 frequency_fls = fls64(frequency);
3074 * We got @count in @nsec, with a target of sample_freq HZ
3075 * the target period becomes:
3078 * period = -------------------
3079 * @nsec * sample_freq
3084 * Reduce accuracy by one bit such that @a and @b converge
3085 * to a similar magnitude.
3087 #define REDUCE_FLS(a, b) \
3089 if (a##_fls > b##_fls) { \
3099 * Reduce accuracy until either term fits in a u64, then proceed with
3100 * the other, so that finally we can do a u64/u64 division.
3102 while (count_fls + sec_fls > 64 && nsec_fls + frequency_fls > 64) {
3103 REDUCE_FLS(nsec, frequency);
3104 REDUCE_FLS(sec, count);
3107 if (count_fls + sec_fls > 64) {
3108 divisor = nsec * frequency;
3110 while (count_fls + sec_fls > 64) {
3111 REDUCE_FLS(count, sec);
3115 dividend = count * sec;
3117 dividend = count * sec;
3119 while (nsec_fls + frequency_fls > 64) {
3120 REDUCE_FLS(nsec, frequency);
3124 divisor = nsec * frequency;
3130 return div64_u64(dividend, divisor);
3133 static DEFINE_PER_CPU(int, perf_throttled_count);
3134 static DEFINE_PER_CPU(u64, perf_throttled_seq);
3136 static void perf_adjust_period(struct perf_event *event, u64 nsec, u64 count, bool disable)
3138 struct hw_perf_event *hwc = &event->hw;
3139 s64 period, sample_period;
3142 period = perf_calculate_period(event, nsec, count);
3144 delta = (s64)(period - hwc->sample_period);
3145 delta = (delta + 7) / 8; /* low pass filter */
3147 sample_period = hwc->sample_period + delta;
3152 hwc->sample_period = sample_period;
3154 if (local64_read(&hwc->period_left) > 8*sample_period) {
3156 event->pmu->stop(event, PERF_EF_UPDATE);
3158 local64_set(&hwc->period_left, 0);
3161 event->pmu->start(event, PERF_EF_RELOAD);
3166 * combine freq adjustment with unthrottling to avoid two passes over the
3167 * events. At the same time, make sure, having freq events does not change
3168 * the rate of unthrottling as that would introduce bias.
3170 static void perf_adjust_freq_unthr_context(struct perf_event_context *ctx,
3173 struct perf_event *event;
3174 struct hw_perf_event *hwc;
3175 u64 now, period = TICK_NSEC;
3179 * only need to iterate over all events iff:
3180 * - context have events in frequency mode (needs freq adjust)
3181 * - there are events to unthrottle on this cpu
3183 if (!(ctx->nr_freq || needs_unthr))
3186 raw_spin_lock(&ctx->lock);
3187 perf_pmu_disable(ctx->pmu);
3189 list_for_each_entry_rcu(event, &ctx->event_list, event_entry) {
3190 if (event->state != PERF_EVENT_STATE_ACTIVE)
3193 if (!event_filter_match(event))
3196 perf_pmu_disable(event->pmu);
3200 if (hwc->interrupts == MAX_INTERRUPTS) {
3201 hwc->interrupts = 0;
3202 perf_log_throttle(event, 1);
3203 event->pmu->start(event, 0);
3206 if (!event->attr.freq || !event->attr.sample_freq)
3210 * stop the event and update event->count
3212 event->pmu->stop(event, PERF_EF_UPDATE);
3214 now = local64_read(&event->count);
3215 delta = now - hwc->freq_count_stamp;
3216 hwc->freq_count_stamp = now;
3220 * reload only if value has changed
3221 * we have stopped the event so tell that
3222 * to perf_adjust_period() to avoid stopping it
3226 perf_adjust_period(event, period, delta, false);
3228 event->pmu->start(event, delta > 0 ? PERF_EF_RELOAD : 0);
3230 perf_pmu_enable(event->pmu);
3233 perf_pmu_enable(ctx->pmu);
3234 raw_spin_unlock(&ctx->lock);
3238 * Round-robin a context's events:
3240 static void rotate_ctx(struct perf_event_context *ctx)
3243 * Rotate the first entry last of non-pinned groups. Rotation might be
3244 * disabled by the inheritance code.
3246 if (!ctx->rotate_disable)
3247 list_rotate_left(&ctx->flexible_groups);
3250 static int perf_rotate_context(struct perf_cpu_context *cpuctx)
3252 struct perf_event_context *ctx = NULL;
3255 if (cpuctx->ctx.nr_events) {
3256 if (cpuctx->ctx.nr_events != cpuctx->ctx.nr_active)
3260 ctx = cpuctx->task_ctx;
3261 if (ctx && ctx->nr_events) {
3262 if (ctx->nr_events != ctx->nr_active)
3269 perf_ctx_lock(cpuctx, cpuctx->task_ctx);
3270 perf_pmu_disable(cpuctx->ctx.pmu);
3272 cpu_ctx_sched_out(cpuctx, EVENT_FLEXIBLE);
3274 ctx_sched_out(ctx, cpuctx, EVENT_FLEXIBLE);
3276 rotate_ctx(&cpuctx->ctx);
3280 perf_event_sched_in(cpuctx, ctx, current);
3282 perf_pmu_enable(cpuctx->ctx.pmu);
3283 perf_ctx_unlock(cpuctx, cpuctx->task_ctx);
3289 void perf_event_task_tick(void)
3291 struct list_head *head = this_cpu_ptr(&active_ctx_list);
3292 struct perf_event_context *ctx, *tmp;
3295 WARN_ON(!irqs_disabled());
3297 __this_cpu_inc(perf_throttled_seq);
3298 throttled = __this_cpu_xchg(perf_throttled_count, 0);
3299 tick_dep_clear_cpu(smp_processor_id(), TICK_DEP_BIT_PERF_EVENTS);
3301 list_for_each_entry_safe(ctx, tmp, head, active_ctx_list)
3302 perf_adjust_freq_unthr_context(ctx, throttled);
3305 static int event_enable_on_exec(struct perf_event *event,
3306 struct perf_event_context *ctx)
3308 if (!event->attr.enable_on_exec)
3311 event->attr.enable_on_exec = 0;
3312 if (event->state >= PERF_EVENT_STATE_INACTIVE)
3315 __perf_event_mark_enabled(event);
3321 * Enable all of a task's events that have been marked enable-on-exec.
3322 * This expects task == current.
3324 static void perf_event_enable_on_exec(int ctxn)
3326 struct perf_event_context *ctx, *clone_ctx = NULL;
3327 struct perf_cpu_context *cpuctx;
3328 struct perf_event *event;
3329 unsigned long flags;
3332 local_irq_save(flags);
3333 ctx = current->perf_event_ctxp[ctxn];
3334 if (!ctx || !ctx->nr_events)
3337 cpuctx = __get_cpu_context(ctx);
3338 perf_ctx_lock(cpuctx, ctx);
3339 ctx_sched_out(ctx, cpuctx, EVENT_TIME);
3340 list_for_each_entry(event, &ctx->event_list, event_entry)
3341 enabled |= event_enable_on_exec(event, ctx);
3344 * Unclone and reschedule this context if we enabled any event.
3347 clone_ctx = unclone_ctx(ctx);
3348 ctx_resched(cpuctx, ctx);
3350 perf_ctx_unlock(cpuctx, ctx);
3353 local_irq_restore(flags);
3359 struct perf_read_data {
3360 struct perf_event *event;
3366 * Cross CPU call to read the hardware event
3368 static void __perf_event_read(void *info)
3370 struct perf_read_data *data = info;
3371 struct perf_event *sub, *event = data->event;
3372 struct perf_event_context *ctx = event->ctx;
3373 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
3374 struct pmu *pmu = event->pmu;
3377 * If this is a task context, we need to check whether it is
3378 * the current task context of this cpu. If not it has been
3379 * scheduled out before the smp call arrived. In that case
3380 * event->count would have been updated to a recent sample
3381 * when the event was scheduled out.
3383 if (ctx->task && cpuctx->task_ctx != ctx)
3386 raw_spin_lock(&ctx->lock);
3387 if (ctx->is_active) {
3388 update_context_time(ctx);
3389 update_cgrp_time_from_event(event);
3392 update_event_times(event);
3393 if (event->state != PERF_EVENT_STATE_ACTIVE)
3402 pmu->start_txn(pmu, PERF_PMU_TXN_READ);
3406 list_for_each_entry(sub, &event->sibling_list, group_entry) {
3407 update_event_times(sub);
3408 if (sub->state == PERF_EVENT_STATE_ACTIVE) {
3410 * Use sibling's PMU rather than @event's since
3411 * sibling could be on different (eg: software) PMU.
3413 sub->pmu->read(sub);
3417 data->ret = pmu->commit_txn(pmu);
3420 raw_spin_unlock(&ctx->lock);
3423 static inline u64 perf_event_count(struct perf_event *event)
3425 if (event->pmu->count)
3426 return event->pmu->count(event);
3428 return __perf_event_count(event);
3432 * NMI-safe method to read a local event, that is an event that
3434 * - either for the current task, or for this CPU
3435 * - does not have inherit set, for inherited task events
3436 * will not be local and we cannot read them atomically
3437 * - must not have a pmu::count method
3439 u64 perf_event_read_local(struct perf_event *event)
3441 unsigned long flags;
3445 * Disabling interrupts avoids all counter scheduling (context
3446 * switches, timer based rotation and IPIs).
3448 local_irq_save(flags);
3450 /* If this is a per-task event, it must be for current */
3451 WARN_ON_ONCE((event->attach_state & PERF_ATTACH_TASK) &&
3452 event->hw.target != current);
3454 /* If this is a per-CPU event, it must be for this CPU */
3455 WARN_ON_ONCE(!(event->attach_state & PERF_ATTACH_TASK) &&
3456 event->cpu != smp_processor_id());
3459 * It must not be an event with inherit set, we cannot read
3460 * all child counters from atomic context.
3462 WARN_ON_ONCE(event->attr.inherit);
3465 * It must not have a pmu::count method, those are not
3468 WARN_ON_ONCE(event->pmu->count);
3471 * If the event is currently on this CPU, its either a per-task event,
3472 * or local to this CPU. Furthermore it means its ACTIVE (otherwise
3475 if (event->oncpu == smp_processor_id())
3476 event->pmu->read(event);
3478 val = local64_read(&event->count);
3479 local_irq_restore(flags);
3484 static int perf_event_read(struct perf_event *event, bool group)
3489 * If event is enabled and currently active on a CPU, update the
3490 * value in the event structure:
3492 if (event->state == PERF_EVENT_STATE_ACTIVE) {
3493 struct perf_read_data data = {
3498 smp_call_function_single(event->oncpu,
3499 __perf_event_read, &data, 1);
3501 } else if (event->state == PERF_EVENT_STATE_INACTIVE) {
3502 struct perf_event_context *ctx = event->ctx;
3503 unsigned long flags;
3505 raw_spin_lock_irqsave(&ctx->lock, flags);
3507 * may read while context is not active
3508 * (e.g., thread is blocked), in that case
3509 * we cannot update context time
3511 if (ctx->is_active) {
3512 update_context_time(ctx);
3513 update_cgrp_time_from_event(event);
3516 update_group_times(event);
3518 update_event_times(event);
3519 raw_spin_unlock_irqrestore(&ctx->lock, flags);
3526 * Initialize the perf_event context in a task_struct:
3528 static void __perf_event_init_context(struct perf_event_context *ctx)
3530 raw_spin_lock_init(&ctx->lock);
3531 mutex_init(&ctx->mutex);
3532 INIT_LIST_HEAD(&ctx->active_ctx_list);
3533 INIT_LIST_HEAD(&ctx->pinned_groups);
3534 INIT_LIST_HEAD(&ctx->flexible_groups);
3535 INIT_LIST_HEAD(&ctx->event_list);
3536 atomic_set(&ctx->refcount, 1);
3539 static struct perf_event_context *
3540 alloc_perf_context(struct pmu *pmu, struct task_struct *task)
3542 struct perf_event_context *ctx;
3544 ctx = kzalloc(sizeof(struct perf_event_context), GFP_KERNEL);
3548 __perf_event_init_context(ctx);
3551 get_task_struct(task);
3558 static struct task_struct *
3559 find_lively_task_by_vpid(pid_t vpid)
3561 struct task_struct *task;
3567 task = find_task_by_vpid(vpid);
3569 get_task_struct(task);
3573 return ERR_PTR(-ESRCH);
3579 * Returns a matching context with refcount and pincount.
3581 static struct perf_event_context *
3582 find_get_context(struct pmu *pmu, struct task_struct *task,
3583 struct perf_event *event)
3585 struct perf_event_context *ctx, *clone_ctx = NULL;
3586 struct perf_cpu_context *cpuctx;
3587 void *task_ctx_data = NULL;
3588 unsigned long flags;
3590 int cpu = event->cpu;
3593 /* Must be root to operate on a CPU event: */
3594 if (perf_paranoid_cpu() && !capable(CAP_SYS_ADMIN))
3595 return ERR_PTR(-EACCES);
3598 * We could be clever and allow to attach a event to an
3599 * offline CPU and activate it when the CPU comes up, but
3602 if (!cpu_online(cpu))
3603 return ERR_PTR(-ENODEV);
3605 cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
3614 ctxn = pmu->task_ctx_nr;
3618 if (event->attach_state & PERF_ATTACH_TASK_DATA) {
3619 task_ctx_data = kzalloc(pmu->task_ctx_size, GFP_KERNEL);
3620 if (!task_ctx_data) {
3627 ctx = perf_lock_task_context(task, ctxn, &flags);
3629 clone_ctx = unclone_ctx(ctx);
3632 if (task_ctx_data && !ctx->task_ctx_data) {
3633 ctx->task_ctx_data = task_ctx_data;
3634 task_ctx_data = NULL;
3636 raw_spin_unlock_irqrestore(&ctx->lock, flags);
3641 ctx = alloc_perf_context(pmu, task);
3646 if (task_ctx_data) {
3647 ctx->task_ctx_data = task_ctx_data;
3648 task_ctx_data = NULL;
3652 mutex_lock(&task->perf_event_mutex);
3654 * If it has already passed perf_event_exit_task().
3655 * we must see PF_EXITING, it takes this mutex too.
3657 if (task->flags & PF_EXITING)
3659 else if (task->perf_event_ctxp[ctxn])
3664 rcu_assign_pointer(task->perf_event_ctxp[ctxn], ctx);
3666 mutex_unlock(&task->perf_event_mutex);
3668 if (unlikely(err)) {
3677 kfree(task_ctx_data);
3681 kfree(task_ctx_data);
3682 return ERR_PTR(err);
3685 static void perf_event_free_filter(struct perf_event *event);
3686 static void perf_event_free_bpf_prog(struct perf_event *event);
3688 static void free_event_rcu(struct rcu_head *head)
3690 struct perf_event *event;
3692 event = container_of(head, struct perf_event, rcu_head);
3694 put_pid_ns(event->ns);
3695 perf_event_free_filter(event);
3699 static void ring_buffer_attach(struct perf_event *event,
3700 struct ring_buffer *rb);
3702 static void detach_sb_event(struct perf_event *event)
3704 struct pmu_event_list *pel = per_cpu_ptr(&pmu_sb_events, event->cpu);
3706 raw_spin_lock(&pel->lock);
3707 list_del_rcu(&event->sb_list);
3708 raw_spin_unlock(&pel->lock);
3711 static bool is_sb_event(struct perf_event *event)
3713 struct perf_event_attr *attr = &event->attr;
3718 if (event->attach_state & PERF_ATTACH_TASK)
3721 if (attr->mmap || attr->mmap_data || attr->mmap2 ||
3722 attr->comm || attr->comm_exec ||
3724 attr->context_switch)
3729 static void unaccount_pmu_sb_event(struct perf_event *event)
3731 if (is_sb_event(event))
3732 detach_sb_event(event);
3735 static void unaccount_event_cpu(struct perf_event *event, int cpu)
3740 if (is_cgroup_event(event))
3741 atomic_dec(&per_cpu(perf_cgroup_events, cpu));
3744 #ifdef CONFIG_NO_HZ_FULL
3745 static DEFINE_SPINLOCK(nr_freq_lock);
3748 static void unaccount_freq_event_nohz(void)
3750 #ifdef CONFIG_NO_HZ_FULL
3751 spin_lock(&nr_freq_lock);
3752 if (atomic_dec_and_test(&nr_freq_events))
3753 tick_nohz_dep_clear(TICK_DEP_BIT_PERF_EVENTS);
3754 spin_unlock(&nr_freq_lock);
3758 static void unaccount_freq_event(void)
3760 if (tick_nohz_full_enabled())
3761 unaccount_freq_event_nohz();
3763 atomic_dec(&nr_freq_events);
3766 static void unaccount_event(struct perf_event *event)
3773 if (event->attach_state & PERF_ATTACH_TASK)
3775 if (event->attr.mmap || event->attr.mmap_data)
3776 atomic_dec(&nr_mmap_events);
3777 if (event->attr.comm)
3778 atomic_dec(&nr_comm_events);
3779 if (event->attr.task)
3780 atomic_dec(&nr_task_events);
3781 if (event->attr.freq)
3782 unaccount_freq_event();
3783 if (event->attr.context_switch) {
3785 atomic_dec(&nr_switch_events);
3787 if (is_cgroup_event(event))
3789 if (has_branch_stack(event))
3793 if (!atomic_add_unless(&perf_sched_count, -1, 1))
3794 schedule_delayed_work(&perf_sched_work, HZ);
3797 unaccount_event_cpu(event, event->cpu);
3799 unaccount_pmu_sb_event(event);
3802 static void perf_sched_delayed(struct work_struct *work)
3804 mutex_lock(&perf_sched_mutex);
3805 if (atomic_dec_and_test(&perf_sched_count))
3806 static_branch_disable(&perf_sched_events);
3807 mutex_unlock(&perf_sched_mutex);
3811 * The following implement mutual exclusion of events on "exclusive" pmus
3812 * (PERF_PMU_CAP_EXCLUSIVE). Such pmus can only have one event scheduled
3813 * at a time, so we disallow creating events that might conflict, namely:
3815 * 1) cpu-wide events in the presence of per-task events,
3816 * 2) per-task events in the presence of cpu-wide events,
3817 * 3) two matching events on the same context.
3819 * The former two cases are handled in the allocation path (perf_event_alloc(),
3820 * _free_event()), the latter -- before the first perf_install_in_context().
3822 static int exclusive_event_init(struct perf_event *event)
3824 struct pmu *pmu = event->pmu;
3826 if (!(pmu->capabilities & PERF_PMU_CAP_EXCLUSIVE))
3830 * Prevent co-existence of per-task and cpu-wide events on the
3831 * same exclusive pmu.
3833 * Negative pmu::exclusive_cnt means there are cpu-wide
3834 * events on this "exclusive" pmu, positive means there are
3837 * Since this is called in perf_event_alloc() path, event::ctx
3838 * doesn't exist yet; it is, however, safe to use PERF_ATTACH_TASK
3839 * to mean "per-task event", because unlike other attach states it
3840 * never gets cleared.
3842 if (event->attach_state & PERF_ATTACH_TASK) {
3843 if (!atomic_inc_unless_negative(&pmu->exclusive_cnt))
3846 if (!atomic_dec_unless_positive(&pmu->exclusive_cnt))
3853 static void exclusive_event_destroy(struct perf_event *event)
3855 struct pmu *pmu = event->pmu;
3857 if (!(pmu->capabilities & PERF_PMU_CAP_EXCLUSIVE))
3860 /* see comment in exclusive_event_init() */
3861 if (event->attach_state & PERF_ATTACH_TASK)
3862 atomic_dec(&pmu->exclusive_cnt);
3864 atomic_inc(&pmu->exclusive_cnt);
3867 static bool exclusive_event_match(struct perf_event *e1, struct perf_event *e2)
3869 if ((e1->pmu->capabilities & PERF_PMU_CAP_EXCLUSIVE) &&
3870 (e1->cpu == e2->cpu ||
3877 /* Called under the same ctx::mutex as perf_install_in_context() */
3878 static bool exclusive_event_installable(struct perf_event *event,
3879 struct perf_event_context *ctx)
3881 struct perf_event *iter_event;
3882 struct pmu *pmu = event->pmu;
3884 if (!(pmu->capabilities & PERF_PMU_CAP_EXCLUSIVE))
3887 list_for_each_entry(iter_event, &ctx->event_list, event_entry) {
3888 if (exclusive_event_match(iter_event, event))
3895 static void perf_addr_filters_splice(struct perf_event *event,
3896 struct list_head *head);
3898 static void _free_event(struct perf_event *event)
3900 irq_work_sync(&event->pending);
3902 unaccount_event(event);
3906 * Can happen when we close an event with re-directed output.
3908 * Since we have a 0 refcount, perf_mmap_close() will skip
3909 * over us; possibly making our ring_buffer_put() the last.
3911 mutex_lock(&event->mmap_mutex);
3912 ring_buffer_attach(event, NULL);
3913 mutex_unlock(&event->mmap_mutex);
3916 if (is_cgroup_event(event))
3917 perf_detach_cgroup(event);
3919 if (!event->parent) {
3920 if (event->attr.sample_type & PERF_SAMPLE_CALLCHAIN)
3921 put_callchain_buffers();
3924 perf_event_free_bpf_prog(event);
3925 perf_addr_filters_splice(event, NULL);
3926 kfree(event->addr_filters_offs);
3929 event->destroy(event);
3932 put_ctx(event->ctx);
3934 exclusive_event_destroy(event);
3935 module_put(event->pmu->module);
3937 call_rcu(&event->rcu_head, free_event_rcu);
3941 * Used to free events which have a known refcount of 1, such as in error paths
3942 * where the event isn't exposed yet and inherited events.
3944 static void free_event(struct perf_event *event)
3946 if (WARN(atomic_long_cmpxchg(&event->refcount, 1, 0) != 1,
3947 "unexpected event refcount: %ld; ptr=%p\n",
3948 atomic_long_read(&event->refcount), event)) {
3949 /* leak to avoid use-after-free */
3957 * Remove user event from the owner task.
3959 static void perf_remove_from_owner(struct perf_event *event)
3961 struct task_struct *owner;
3965 * Matches the smp_store_release() in perf_event_exit_task(). If we
3966 * observe !owner it means the list deletion is complete and we can
3967 * indeed free this event, otherwise we need to serialize on
3968 * owner->perf_event_mutex.
3970 owner = lockless_dereference(event->owner);
3973 * Since delayed_put_task_struct() also drops the last
3974 * task reference we can safely take a new reference
3975 * while holding the rcu_read_lock().
3977 get_task_struct(owner);
3983 * If we're here through perf_event_exit_task() we're already
3984 * holding ctx->mutex which would be an inversion wrt. the
3985 * normal lock order.
3987 * However we can safely take this lock because its the child
3990 mutex_lock_nested(&owner->perf_event_mutex, SINGLE_DEPTH_NESTING);
3993 * We have to re-check the event->owner field, if it is cleared
3994 * we raced with perf_event_exit_task(), acquiring the mutex
3995 * ensured they're done, and we can proceed with freeing the
3999 list_del_init(&event->owner_entry);
4000 smp_store_release(&event->owner, NULL);
4002 mutex_unlock(&owner->perf_event_mutex);
4003 put_task_struct(owner);
4007 static void put_event(struct perf_event *event)
4009 if (!atomic_long_dec_and_test(&event->refcount))
4016 * Kill an event dead; while event:refcount will preserve the event
4017 * object, it will not preserve its functionality. Once the last 'user'
4018 * gives up the object, we'll destroy the thing.
4020 int perf_event_release_kernel(struct perf_event *event)
4022 struct perf_event_context *ctx = event->ctx;
4023 struct perf_event *child, *tmp;
4026 * If we got here through err_file: fput(event_file); we will not have
4027 * attached to a context yet.
4030 WARN_ON_ONCE(event->attach_state &
4031 (PERF_ATTACH_CONTEXT|PERF_ATTACH_GROUP));
4035 if (!is_kernel_event(event))
4036 perf_remove_from_owner(event);
4038 ctx = perf_event_ctx_lock(event);
4039 WARN_ON_ONCE(ctx->parent_ctx);
4040 perf_remove_from_context(event, DETACH_GROUP);
4042 raw_spin_lock_irq(&ctx->lock);
4044 * Mark this even as STATE_DEAD, there is no external reference to it
4047 * Anybody acquiring event->child_mutex after the below loop _must_
4048 * also see this, most importantly inherit_event() which will avoid
4049 * placing more children on the list.
4051 * Thus this guarantees that we will in fact observe and kill _ALL_
4054 event->state = PERF_EVENT_STATE_DEAD;
4055 raw_spin_unlock_irq(&ctx->lock);
4057 perf_event_ctx_unlock(event, ctx);
4060 mutex_lock(&event->child_mutex);
4061 list_for_each_entry(child, &event->child_list, child_list) {
4064 * Cannot change, child events are not migrated, see the
4065 * comment with perf_event_ctx_lock_nested().
4067 ctx = lockless_dereference(child->ctx);
4069 * Since child_mutex nests inside ctx::mutex, we must jump
4070 * through hoops. We start by grabbing a reference on the ctx.
4072 * Since the event cannot get freed while we hold the
4073 * child_mutex, the context must also exist and have a !0
4079 * Now that we have a ctx ref, we can drop child_mutex, and
4080 * acquire ctx::mutex without fear of it going away. Then we
4081 * can re-acquire child_mutex.
4083 mutex_unlock(&event->child_mutex);
4084 mutex_lock(&ctx->mutex);
4085 mutex_lock(&event->child_mutex);
4088 * Now that we hold ctx::mutex and child_mutex, revalidate our
4089 * state, if child is still the first entry, it didn't get freed
4090 * and we can continue doing so.
4092 tmp = list_first_entry_or_null(&event->child_list,
4093 struct perf_event, child_list);
4095 perf_remove_from_context(child, DETACH_GROUP);
4096 list_del(&child->child_list);
4099 * This matches the refcount bump in inherit_event();
4100 * this can't be the last reference.
4105 mutex_unlock(&event->child_mutex);
4106 mutex_unlock(&ctx->mutex);
4110 mutex_unlock(&event->child_mutex);
4113 put_event(event); /* Must be the 'last' reference */
4116 EXPORT_SYMBOL_GPL(perf_event_release_kernel);
4119 * Called when the last reference to the file is gone.
4121 static int perf_release(struct inode *inode, struct file *file)
4123 perf_event_release_kernel(file->private_data);
4127 u64 perf_event_read_value(struct perf_event *event, u64 *enabled, u64 *running)
4129 struct perf_event *child;
4135 mutex_lock(&event->child_mutex);
4137 (void)perf_event_read(event, false);
4138 total += perf_event_count(event);
4140 *enabled += event->total_time_enabled +
4141 atomic64_read(&event->child_total_time_enabled);
4142 *running += event->total_time_running +
4143 atomic64_read(&event->child_total_time_running);
4145 list_for_each_entry(child, &event->child_list, child_list) {
4146 (void)perf_event_read(child, false);
4147 total += perf_event_count(child);
4148 *enabled += child->total_time_enabled;
4149 *running += child->total_time_running;
4151 mutex_unlock(&event->child_mutex);
4155 EXPORT_SYMBOL_GPL(perf_event_read_value);
4157 static int __perf_read_group_add(struct perf_event *leader,
4158 u64 read_format, u64 *values)
4160 struct perf_event *sub;
4161 int n = 1; /* skip @nr */
4164 ret = perf_event_read(leader, true);
4169 * Since we co-schedule groups, {enabled,running} times of siblings
4170 * will be identical to those of the leader, so we only publish one
4173 if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED) {
4174 values[n++] += leader->total_time_enabled +
4175 atomic64_read(&leader->child_total_time_enabled);
4178 if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING) {
4179 values[n++] += leader->total_time_running +
4180 atomic64_read(&leader->child_total_time_running);
4184 * Write {count,id} tuples for every sibling.
4186 values[n++] += perf_event_count(leader);
4187 if (read_format & PERF_FORMAT_ID)
4188 values[n++] = primary_event_id(leader);
4190 list_for_each_entry(sub, &leader->sibling_list, group_entry) {
4191 values[n++] += perf_event_count(sub);
4192 if (read_format & PERF_FORMAT_ID)
4193 values[n++] = primary_event_id(sub);
4199 static int perf_read_group(struct perf_event *event,
4200 u64 read_format, char __user *buf)
4202 struct perf_event *leader = event->group_leader, *child;
4203 struct perf_event_context *ctx = leader->ctx;
4207 lockdep_assert_held(&ctx->mutex);
4209 values = kzalloc(event->read_size, GFP_KERNEL);
4213 values[0] = 1 + leader->nr_siblings;
4216 * By locking the child_mutex of the leader we effectively
4217 * lock the child list of all siblings.. XXX explain how.
4219 mutex_lock(&leader->child_mutex);
4221 ret = __perf_read_group_add(leader, read_format, values);
4225 list_for_each_entry(child, &leader->child_list, child_list) {
4226 ret = __perf_read_group_add(child, read_format, values);
4231 mutex_unlock(&leader->child_mutex);
4233 ret = event->read_size;
4234 if (copy_to_user(buf, values, event->read_size))
4239 mutex_unlock(&leader->child_mutex);
4245 static int perf_read_one(struct perf_event *event,
4246 u64 read_format, char __user *buf)
4248 u64 enabled, running;
4252 values[n++] = perf_event_read_value(event, &enabled, &running);
4253 if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED)
4254 values[n++] = enabled;
4255 if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING)
4256 values[n++] = running;
4257 if (read_format & PERF_FORMAT_ID)
4258 values[n++] = primary_event_id(event);
4260 if (copy_to_user(buf, values, n * sizeof(u64)))
4263 return n * sizeof(u64);
4266 static bool is_event_hup(struct perf_event *event)
4270 if (event->state > PERF_EVENT_STATE_EXIT)
4273 mutex_lock(&event->child_mutex);
4274 no_children = list_empty(&event->child_list);
4275 mutex_unlock(&event->child_mutex);
4280 * Read the performance event - simple non blocking version for now
4283 __perf_read(struct perf_event *event, char __user *buf, size_t count)
4285 u64 read_format = event->attr.read_format;
4289 * Return end-of-file for a read on a event that is in
4290 * error state (i.e. because it was pinned but it couldn't be
4291 * scheduled on to the CPU at some point).
4293 if (event->state == PERF_EVENT_STATE_ERROR)
4296 if (count < event->read_size)
4299 WARN_ON_ONCE(event->ctx->parent_ctx);
4300 if (read_format & PERF_FORMAT_GROUP)
4301 ret = perf_read_group(event, read_format, buf);
4303 ret = perf_read_one(event, read_format, buf);
4309 perf_read(struct file *file, char __user *buf, size_t count, loff_t *ppos)
4311 struct perf_event *event = file->private_data;
4312 struct perf_event_context *ctx;
4315 ctx = perf_event_ctx_lock(event);
4316 ret = __perf_read(event, buf, count);
4317 perf_event_ctx_unlock(event, ctx);
4322 static unsigned int perf_poll(struct file *file, poll_table *wait)
4324 struct perf_event *event = file->private_data;
4325 struct ring_buffer *rb;
4326 unsigned int events = POLLHUP;
4328 poll_wait(file, &event->waitq, wait);
4330 if (is_event_hup(event))
4334 * Pin the event->rb by taking event->mmap_mutex; otherwise
4335 * perf_event_set_output() can swizzle our rb and make us miss wakeups.
4337 mutex_lock(&event->mmap_mutex);
4340 events = atomic_xchg(&rb->poll, 0);
4341 mutex_unlock(&event->mmap_mutex);
4345 static void _perf_event_reset(struct perf_event *event)
4347 (void)perf_event_read(event, false);
4348 local64_set(&event->count, 0);
4349 perf_event_update_userpage(event);
4353 * Holding the top-level event's child_mutex means that any
4354 * descendant process that has inherited this event will block
4355 * in perf_event_exit_event() if it goes to exit, thus satisfying the
4356 * task existence requirements of perf_event_enable/disable.
4358 static void perf_event_for_each_child(struct perf_event *event,
4359 void (*func)(struct perf_event *))
4361 struct perf_event *child;
4363 WARN_ON_ONCE(event->ctx->parent_ctx);
4365 mutex_lock(&event->child_mutex);
4367 list_for_each_entry(child, &event->child_list, child_list)
4369 mutex_unlock(&event->child_mutex);
4372 static void perf_event_for_each(struct perf_event *event,
4373 void (*func)(struct perf_event *))
4375 struct perf_event_context *ctx = event->ctx;
4376 struct perf_event *sibling;
4378 lockdep_assert_held(&ctx->mutex);
4380 event = event->group_leader;
4382 perf_event_for_each_child(event, func);
4383 list_for_each_entry(sibling, &event->sibling_list, group_entry)
4384 perf_event_for_each_child(sibling, func);
4387 static void __perf_event_period(struct perf_event *event,
4388 struct perf_cpu_context *cpuctx,
4389 struct perf_event_context *ctx,
4392 u64 value = *((u64 *)info);
4395 if (event->attr.freq) {
4396 event->attr.sample_freq = value;
4398 event->attr.sample_period = value;
4399 event->hw.sample_period = value;
4402 active = (event->state == PERF_EVENT_STATE_ACTIVE);
4404 perf_pmu_disable(ctx->pmu);
4406 * We could be throttled; unthrottle now to avoid the tick
4407 * trying to unthrottle while we already re-started the event.
4409 if (event->hw.interrupts == MAX_INTERRUPTS) {
4410 event->hw.interrupts = 0;
4411 perf_log_throttle(event, 1);
4413 event->pmu->stop(event, PERF_EF_UPDATE);
4416 local64_set(&event->hw.period_left, 0);
4419 event->pmu->start(event, PERF_EF_RELOAD);
4420 perf_pmu_enable(ctx->pmu);
4424 static int perf_event_period(struct perf_event *event, u64 __user *arg)
4428 if (!is_sampling_event(event))
4431 if (copy_from_user(&value, arg, sizeof(value)))
4437 if (event->attr.freq && value > sysctl_perf_event_sample_rate)
4440 event_function_call(event, __perf_event_period, &value);
4445 static const struct file_operations perf_fops;
4447 static inline int perf_fget_light(int fd, struct fd *p)
4449 struct fd f = fdget(fd);
4453 if (f.file->f_op != &perf_fops) {
4461 static int perf_event_set_output(struct perf_event *event,
4462 struct perf_event *output_event);
4463 static int perf_event_set_filter(struct perf_event *event, void __user *arg);
4464 static int perf_event_set_bpf_prog(struct perf_event *event, u32 prog_fd);
4466 static long _perf_ioctl(struct perf_event *event, unsigned int cmd, unsigned long arg)
4468 void (*func)(struct perf_event *);
4472 case PERF_EVENT_IOC_ENABLE:
4473 func = _perf_event_enable;
4475 case PERF_EVENT_IOC_DISABLE:
4476 func = _perf_event_disable;
4478 case PERF_EVENT_IOC_RESET:
4479 func = _perf_event_reset;
4482 case PERF_EVENT_IOC_REFRESH:
4483 return _perf_event_refresh(event, arg);
4485 case PERF_EVENT_IOC_PERIOD:
4486 return perf_event_period(event, (u64 __user *)arg);
4488 case PERF_EVENT_IOC_ID:
4490 u64 id = primary_event_id(event);
4492 if (copy_to_user((void __user *)arg, &id, sizeof(id)))
4497 case PERF_EVENT_IOC_SET_OUTPUT:
4501 struct perf_event *output_event;
4503 ret = perf_fget_light(arg, &output);
4506 output_event = output.file->private_data;
4507 ret = perf_event_set_output(event, output_event);
4510 ret = perf_event_set_output(event, NULL);
4515 case PERF_EVENT_IOC_SET_FILTER:
4516 return perf_event_set_filter(event, (void __user *)arg);
4518 case PERF_EVENT_IOC_SET_BPF:
4519 return perf_event_set_bpf_prog(event, arg);
4521 case PERF_EVENT_IOC_PAUSE_OUTPUT: {
4522 struct ring_buffer *rb;
4525 rb = rcu_dereference(event->rb);
4526 if (!rb || !rb->nr_pages) {
4530 rb_toggle_paused(rb, !!arg);
4538 if (flags & PERF_IOC_FLAG_GROUP)
4539 perf_event_for_each(event, func);
4541 perf_event_for_each_child(event, func);
4546 static long perf_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
4548 struct perf_event *event = file->private_data;
4549 struct perf_event_context *ctx;
4552 ctx = perf_event_ctx_lock(event);
4553 ret = _perf_ioctl(event, cmd, arg);
4554 perf_event_ctx_unlock(event, ctx);
4559 #ifdef CONFIG_COMPAT
4560 static long perf_compat_ioctl(struct file *file, unsigned int cmd,
4563 switch (_IOC_NR(cmd)) {
4564 case _IOC_NR(PERF_EVENT_IOC_SET_FILTER):
4565 case _IOC_NR(PERF_EVENT_IOC_ID):
4566 /* Fix up pointer size (usually 4 -> 8 in 32-on-64-bit case */
4567 if (_IOC_SIZE(cmd) == sizeof(compat_uptr_t)) {
4568 cmd &= ~IOCSIZE_MASK;
4569 cmd |= sizeof(void *) << IOCSIZE_SHIFT;
4573 return perf_ioctl(file, cmd, arg);
4576 # define perf_compat_ioctl NULL
4579 int perf_event_task_enable(void)
4581 struct perf_event_context *ctx;
4582 struct perf_event *event;
4584 mutex_lock(¤t->perf_event_mutex);
4585 list_for_each_entry(event, ¤t->perf_event_list, owner_entry) {
4586 ctx = perf_event_ctx_lock(event);
4587 perf_event_for_each_child(event, _perf_event_enable);
4588 perf_event_ctx_unlock(event, ctx);
4590 mutex_unlock(¤t->perf_event_mutex);
4595 int perf_event_task_disable(void)
4597 struct perf_event_context *ctx;
4598 struct perf_event *event;
4600 mutex_lock(¤t->perf_event_mutex);
4601 list_for_each_entry(event, ¤t->perf_event_list, owner_entry) {
4602 ctx = perf_event_ctx_lock(event);
4603 perf_event_for_each_child(event, _perf_event_disable);
4604 perf_event_ctx_unlock(event, ctx);
4606 mutex_unlock(¤t->perf_event_mutex);
4611 static int perf_event_index(struct perf_event *event)
4613 if (event->hw.state & PERF_HES_STOPPED)
4616 if (event->state != PERF_EVENT_STATE_ACTIVE)
4619 return event->pmu->event_idx(event);
4622 static void calc_timer_values(struct perf_event *event,
4629 *now = perf_clock();
4630 ctx_time = event->shadow_ctx_time + *now;
4631 *enabled = ctx_time - event->tstamp_enabled;
4632 *running = ctx_time - event->tstamp_running;
4635 static void perf_event_init_userpage(struct perf_event *event)
4637 struct perf_event_mmap_page *userpg;
4638 struct ring_buffer *rb;
4641 rb = rcu_dereference(event->rb);
4645 userpg = rb->user_page;
4647 /* Allow new userspace to detect that bit 0 is deprecated */
4648 userpg->cap_bit0_is_deprecated = 1;
4649 userpg->size = offsetof(struct perf_event_mmap_page, __reserved);
4650 userpg->data_offset = PAGE_SIZE;
4651 userpg->data_size = perf_data_size(rb);
4657 void __weak arch_perf_update_userpage(
4658 struct perf_event *event, struct perf_event_mmap_page *userpg, u64 now)
4663 * Callers need to ensure there can be no nesting of this function, otherwise
4664 * the seqlock logic goes bad. We can not serialize this because the arch
4665 * code calls this from NMI context.
4667 void perf_event_update_userpage(struct perf_event *event)
4669 struct perf_event_mmap_page *userpg;
4670 struct ring_buffer *rb;
4671 u64 enabled, running, now;
4674 rb = rcu_dereference(event->rb);
4679 * compute total_time_enabled, total_time_running
4680 * based on snapshot values taken when the event
4681 * was last scheduled in.
4683 * we cannot simply called update_context_time()
4684 * because of locking issue as we can be called in
4687 calc_timer_values(event, &now, &enabled, &running);
4689 userpg = rb->user_page;
4691 * Disable preemption so as to not let the corresponding user-space
4692 * spin too long if we get preempted.
4697 userpg->index = perf_event_index(event);
4698 userpg->offset = perf_event_count(event);
4700 userpg->offset -= local64_read(&event->hw.prev_count);
4702 userpg->time_enabled = enabled +
4703 atomic64_read(&event->child_total_time_enabled);
4705 userpg->time_running = running +
4706 atomic64_read(&event->child_total_time_running);
4708 arch_perf_update_userpage(event, userpg, now);
4717 static int perf_mmap_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
4719 struct perf_event *event = vma->vm_file->private_data;
4720 struct ring_buffer *rb;
4721 int ret = VM_FAULT_SIGBUS;
4723 if (vmf->flags & FAULT_FLAG_MKWRITE) {
4724 if (vmf->pgoff == 0)
4730 rb = rcu_dereference(event->rb);
4734 if (vmf->pgoff && (vmf->flags & FAULT_FLAG_WRITE))
4737 vmf->page = perf_mmap_to_page(rb, vmf->pgoff);
4741 get_page(vmf->page);
4742 vmf->page->mapping = vma->vm_file->f_mapping;
4743 vmf->page->index = vmf->pgoff;
4752 static void ring_buffer_attach(struct perf_event *event,
4753 struct ring_buffer *rb)
4755 struct ring_buffer *old_rb = NULL;
4756 unsigned long flags;
4760 * Should be impossible, we set this when removing
4761 * event->rb_entry and wait/clear when adding event->rb_entry.
4763 WARN_ON_ONCE(event->rcu_pending);
4766 spin_lock_irqsave(&old_rb->event_lock, flags);
4767 list_del_rcu(&event->rb_entry);
4768 spin_unlock_irqrestore(&old_rb->event_lock, flags);
4770 event->rcu_batches = get_state_synchronize_rcu();
4771 event->rcu_pending = 1;
4775 if (event->rcu_pending) {
4776 cond_synchronize_rcu(event->rcu_batches);
4777 event->rcu_pending = 0;
4780 spin_lock_irqsave(&rb->event_lock, flags);
4781 list_add_rcu(&event->rb_entry, &rb->event_list);
4782 spin_unlock_irqrestore(&rb->event_lock, flags);
4785 rcu_assign_pointer(event->rb, rb);
4788 ring_buffer_put(old_rb);
4790 * Since we detached before setting the new rb, so that we
4791 * could attach the new rb, we could have missed a wakeup.
4794 wake_up_all(&event->waitq);
4798 static void ring_buffer_wakeup(struct perf_event *event)
4800 struct ring_buffer *rb;
4803 rb = rcu_dereference(event->rb);
4805 list_for_each_entry_rcu(event, &rb->event_list, rb_entry)
4806 wake_up_all(&event->waitq);
4811 struct ring_buffer *ring_buffer_get(struct perf_event *event)
4813 struct ring_buffer *rb;
4816 rb = rcu_dereference(event->rb);
4818 if (!atomic_inc_not_zero(&rb->refcount))
4826 void ring_buffer_put(struct ring_buffer *rb)
4828 if (!atomic_dec_and_test(&rb->refcount))
4831 WARN_ON_ONCE(!list_empty(&rb->event_list));
4833 call_rcu(&rb->rcu_head, rb_free_rcu);
4836 static void perf_mmap_open(struct vm_area_struct *vma)
4838 struct perf_event *event = vma->vm_file->private_data;
4840 atomic_inc(&event->mmap_count);
4841 atomic_inc(&event->rb->mmap_count);
4844 atomic_inc(&event->rb->aux_mmap_count);
4846 if (event->pmu->event_mapped)
4847 event->pmu->event_mapped(event);
4850 static void perf_pmu_output_stop(struct perf_event *event);
4853 * A buffer can be mmap()ed multiple times; either directly through the same
4854 * event, or through other events by use of perf_event_set_output().
4856 * In order to undo the VM accounting done by perf_mmap() we need to destroy
4857 * the buffer here, where we still have a VM context. This means we need
4858 * to detach all events redirecting to us.
4860 static void perf_mmap_close(struct vm_area_struct *vma)
4862 struct perf_event *event = vma->vm_file->private_data;
4864 struct ring_buffer *rb = ring_buffer_get(event);
4865 struct user_struct *mmap_user = rb->mmap_user;
4866 int mmap_locked = rb->mmap_locked;
4867 unsigned long size = perf_data_size(rb);
4869 if (event->pmu->event_unmapped)
4870 event->pmu->event_unmapped(event);
4873 * rb->aux_mmap_count will always drop before rb->mmap_count and
4874 * event->mmap_count, so it is ok to use event->mmap_mutex to
4875 * serialize with perf_mmap here.
4877 if (rb_has_aux(rb) && vma->vm_pgoff == rb->aux_pgoff &&
4878 atomic_dec_and_mutex_lock(&rb->aux_mmap_count, &event->mmap_mutex)) {
4880 * Stop all AUX events that are writing to this buffer,
4881 * so that we can free its AUX pages and corresponding PMU
4882 * data. Note that after rb::aux_mmap_count dropped to zero,
4883 * they won't start any more (see perf_aux_output_begin()).
4885 perf_pmu_output_stop(event);
4887 /* now it's safe to free the pages */
4888 atomic_long_sub(rb->aux_nr_pages, &mmap_user->locked_vm);
4889 vma->vm_mm->pinned_vm -= rb->aux_mmap_locked;
4891 /* this has to be the last one */
4893 WARN_ON_ONCE(atomic_read(&rb->aux_refcount));
4895 mutex_unlock(&event->mmap_mutex);
4898 atomic_dec(&rb->mmap_count);
4900 if (!atomic_dec_and_mutex_lock(&event->mmap_count, &event->mmap_mutex))
4903 ring_buffer_attach(event, NULL);
4904 mutex_unlock(&event->mmap_mutex);
4906 /* If there's still other mmap()s of this buffer, we're done. */
4907 if (atomic_read(&rb->mmap_count))
4911 * No other mmap()s, detach from all other events that might redirect
4912 * into the now unreachable buffer. Somewhat complicated by the
4913 * fact that rb::event_lock otherwise nests inside mmap_mutex.
4917 list_for_each_entry_rcu(event, &rb->event_list, rb_entry) {
4918 if (!atomic_long_inc_not_zero(&event->refcount)) {
4920 * This event is en-route to free_event() which will
4921 * detach it and remove it from the list.
4927 mutex_lock(&event->mmap_mutex);
4929 * Check we didn't race with perf_event_set_output() which can
4930 * swizzle the rb from under us while we were waiting to
4931 * acquire mmap_mutex.
4933 * If we find a different rb; ignore this event, a next
4934 * iteration will no longer find it on the list. We have to
4935 * still restart the iteration to make sure we're not now
4936 * iterating the wrong list.
4938 if (event->rb == rb)
4939 ring_buffer_attach(event, NULL);
4941 mutex_unlock(&event->mmap_mutex);
4945 * Restart the iteration; either we're on the wrong list or
4946 * destroyed its integrity by doing a deletion.
4953 * It could be there's still a few 0-ref events on the list; they'll
4954 * get cleaned up by free_event() -- they'll also still have their
4955 * ref on the rb and will free it whenever they are done with it.
4957 * Aside from that, this buffer is 'fully' detached and unmapped,
4958 * undo the VM accounting.
4961 atomic_long_sub((size >> PAGE_SHIFT) + 1, &mmap_user->locked_vm);
4962 vma->vm_mm->pinned_vm -= mmap_locked;
4963 free_uid(mmap_user);
4966 ring_buffer_put(rb); /* could be last */
4969 static const struct vm_operations_struct perf_mmap_vmops = {
4970 .open = perf_mmap_open,
4971 .close = perf_mmap_close, /* non mergable */
4972 .fault = perf_mmap_fault,
4973 .page_mkwrite = perf_mmap_fault,
4976 static int perf_mmap(struct file *file, struct vm_area_struct *vma)
4978 struct perf_event *event = file->private_data;
4979 unsigned long user_locked, user_lock_limit;
4980 struct user_struct *user = current_user();
4981 unsigned long locked, lock_limit;
4982 struct ring_buffer *rb = NULL;
4983 unsigned long vma_size;
4984 unsigned long nr_pages;
4985 long user_extra = 0, extra = 0;
4986 int ret = 0, flags = 0;
4989 * Don't allow mmap() of inherited per-task counters. This would
4990 * create a performance issue due to all children writing to the
4993 if (event->cpu == -1 && event->attr.inherit)
4996 if (!(vma->vm_flags & VM_SHARED))
4999 vma_size = vma->vm_end - vma->vm_start;
5001 if (vma->vm_pgoff == 0) {
5002 nr_pages = (vma_size / PAGE_SIZE) - 1;
5005 * AUX area mapping: if rb->aux_nr_pages != 0, it's already
5006 * mapped, all subsequent mappings should have the same size
5007 * and offset. Must be above the normal perf buffer.
5009 u64 aux_offset, aux_size;
5014 nr_pages = vma_size / PAGE_SIZE;
5016 mutex_lock(&event->mmap_mutex);
5023 aux_offset = ACCESS_ONCE(rb->user_page->aux_offset);
5024 aux_size = ACCESS_ONCE(rb->user_page->aux_size);
5026 if (aux_offset < perf_data_size(rb) + PAGE_SIZE)
5029 if (aux_offset != vma->vm_pgoff << PAGE_SHIFT)
5032 /* already mapped with a different offset */
5033 if (rb_has_aux(rb) && rb->aux_pgoff != vma->vm_pgoff)
5036 if (aux_size != vma_size || aux_size != nr_pages * PAGE_SIZE)
5039 /* already mapped with a different size */
5040 if (rb_has_aux(rb) && rb->aux_nr_pages != nr_pages)
5043 if (!is_power_of_2(nr_pages))
5046 if (!atomic_inc_not_zero(&rb->mmap_count))
5049 if (rb_has_aux(rb)) {
5050 atomic_inc(&rb->aux_mmap_count);
5055 atomic_set(&rb->aux_mmap_count, 1);
5056 user_extra = nr_pages;
5062 * If we have rb pages ensure they're a power-of-two number, so we
5063 * can do bitmasks instead of modulo.
5065 if (nr_pages != 0 && !is_power_of_2(nr_pages))
5068 if (vma_size != PAGE_SIZE * (1 + nr_pages))
5071 WARN_ON_ONCE(event->ctx->parent_ctx);
5073 mutex_lock(&event->mmap_mutex);
5075 if (event->rb->nr_pages != nr_pages) {
5080 if (!atomic_inc_not_zero(&event->rb->mmap_count)) {
5082 * Raced against perf_mmap_close() through
5083 * perf_event_set_output(). Try again, hope for better
5086 mutex_unlock(&event->mmap_mutex);
5093 user_extra = nr_pages + 1;
5096 user_lock_limit = sysctl_perf_event_mlock >> (PAGE_SHIFT - 10);
5099 * Increase the limit linearly with more CPUs:
5101 user_lock_limit *= num_online_cpus();
5103 user_locked = atomic_long_read(&user->locked_vm) + user_extra;
5105 if (user_locked > user_lock_limit)
5106 extra = user_locked - user_lock_limit;
5108 lock_limit = rlimit(RLIMIT_MEMLOCK);
5109 lock_limit >>= PAGE_SHIFT;
5110 locked = vma->vm_mm->pinned_vm + extra;
5112 if ((locked > lock_limit) && perf_paranoid_tracepoint_raw() &&
5113 !capable(CAP_IPC_LOCK)) {
5118 WARN_ON(!rb && event->rb);
5120 if (vma->vm_flags & VM_WRITE)
5121 flags |= RING_BUFFER_WRITABLE;
5124 rb = rb_alloc(nr_pages,
5125 event->attr.watermark ? event->attr.wakeup_watermark : 0,
5133 atomic_set(&rb->mmap_count, 1);
5134 rb->mmap_user = get_current_user();
5135 rb->mmap_locked = extra;
5137 ring_buffer_attach(event, rb);
5139 perf_event_init_userpage(event);
5140 perf_event_update_userpage(event);
5142 ret = rb_alloc_aux(rb, event, vma->vm_pgoff, nr_pages,
5143 event->attr.aux_watermark, flags);
5145 rb->aux_mmap_locked = extra;
5150 atomic_long_add(user_extra, &user->locked_vm);
5151 vma->vm_mm->pinned_vm += extra;
5153 atomic_inc(&event->mmap_count);
5155 atomic_dec(&rb->mmap_count);
5158 mutex_unlock(&event->mmap_mutex);
5161 * Since pinned accounting is per vm we cannot allow fork() to copy our
5164 vma->vm_flags |= VM_DONTCOPY | VM_DONTEXPAND | VM_DONTDUMP;
5165 vma->vm_ops = &perf_mmap_vmops;
5167 if (event->pmu->event_mapped)
5168 event->pmu->event_mapped(event);
5173 static int perf_fasync(int fd, struct file *filp, int on)
5175 struct inode *inode = file_inode(filp);
5176 struct perf_event *event = filp->private_data;
5180 retval = fasync_helper(fd, filp, on, &event->fasync);
5181 inode_unlock(inode);
5189 static const struct file_operations perf_fops = {
5190 .llseek = no_llseek,
5191 .release = perf_release,
5194 .unlocked_ioctl = perf_ioctl,
5195 .compat_ioctl = perf_compat_ioctl,
5197 .fasync = perf_fasync,
5203 * If there's data, ensure we set the poll() state and publish everything
5204 * to user-space before waking everybody up.
5207 static inline struct fasync_struct **perf_event_fasync(struct perf_event *event)
5209 /* only the parent has fasync state */
5211 event = event->parent;
5212 return &event->fasync;
5215 void perf_event_wakeup(struct perf_event *event)
5217 ring_buffer_wakeup(event);
5219 if (event->pending_kill) {
5220 kill_fasync(perf_event_fasync(event), SIGIO, event->pending_kill);
5221 event->pending_kill = 0;
5225 static void perf_pending_event(struct irq_work *entry)
5227 struct perf_event *event = container_of(entry,
5228 struct perf_event, pending);
5231 rctx = perf_swevent_get_recursion_context();
5233 * If we 'fail' here, that's OK, it means recursion is already disabled
5234 * and we won't recurse 'further'.
5237 if (event->pending_disable) {
5238 event->pending_disable = 0;
5239 perf_event_disable_local(event);
5242 if (event->pending_wakeup) {
5243 event->pending_wakeup = 0;
5244 perf_event_wakeup(event);
5248 perf_swevent_put_recursion_context(rctx);
5252 * We assume there is only KVM supporting the callbacks.
5253 * Later on, we might change it to a list if there is
5254 * another virtualization implementation supporting the callbacks.
5256 struct perf_guest_info_callbacks *perf_guest_cbs;
5258 int perf_register_guest_info_callbacks(struct perf_guest_info_callbacks *cbs)
5260 perf_guest_cbs = cbs;
5263 EXPORT_SYMBOL_GPL(perf_register_guest_info_callbacks);
5265 int perf_unregister_guest_info_callbacks(struct perf_guest_info_callbacks *cbs)
5267 perf_guest_cbs = NULL;
5270 EXPORT_SYMBOL_GPL(perf_unregister_guest_info_callbacks);
5273 perf_output_sample_regs(struct perf_output_handle *handle,
5274 struct pt_regs *regs, u64 mask)
5278 for_each_set_bit(bit, (const unsigned long *) &mask,
5279 sizeof(mask) * BITS_PER_BYTE) {
5282 val = perf_reg_value(regs, bit);
5283 perf_output_put(handle, val);
5287 static void perf_sample_regs_user(struct perf_regs *regs_user,
5288 struct pt_regs *regs,
5289 struct pt_regs *regs_user_copy)
5291 if (user_mode(regs)) {
5292 regs_user->abi = perf_reg_abi(current);
5293 regs_user->regs = regs;
5294 } else if (current->mm) {
5295 perf_get_regs_user(regs_user, regs, regs_user_copy);
5297 regs_user->abi = PERF_SAMPLE_REGS_ABI_NONE;
5298 regs_user->regs = NULL;
5302 static void perf_sample_regs_intr(struct perf_regs *regs_intr,
5303 struct pt_regs *regs)
5305 regs_intr->regs = regs;
5306 regs_intr->abi = perf_reg_abi(current);
5311 * Get remaining task size from user stack pointer.
5313 * It'd be better to take stack vma map and limit this more
5314 * precisly, but there's no way to get it safely under interrupt,
5315 * so using TASK_SIZE as limit.
5317 static u64 perf_ustack_task_size(struct pt_regs *regs)
5319 unsigned long addr = perf_user_stack_pointer(regs);
5321 if (!addr || addr >= TASK_SIZE)
5324 return TASK_SIZE - addr;
5328 perf_sample_ustack_size(u16 stack_size, u16 header_size,
5329 struct pt_regs *regs)
5333 /* No regs, no stack pointer, no dump. */
5338 * Check if we fit in with the requested stack size into the:
5340 * If we don't, we limit the size to the TASK_SIZE.
5342 * - remaining sample size
5343 * If we don't, we customize the stack size to
5344 * fit in to the remaining sample size.
5347 task_size = min((u64) USHRT_MAX, perf_ustack_task_size(regs));
5348 stack_size = min(stack_size, (u16) task_size);
5350 /* Current header size plus static size and dynamic size. */
5351 header_size += 2 * sizeof(u64);
5353 /* Do we fit in with the current stack dump size? */
5354 if ((u16) (header_size + stack_size) < header_size) {
5356 * If we overflow the maximum size for the sample,
5357 * we customize the stack dump size to fit in.
5359 stack_size = USHRT_MAX - header_size - sizeof(u64);
5360 stack_size = round_up(stack_size, sizeof(u64));
5367 perf_output_sample_ustack(struct perf_output_handle *handle, u64 dump_size,
5368 struct pt_regs *regs)
5370 /* Case of a kernel thread, nothing to dump */
5373 perf_output_put(handle, size);
5382 * - the size requested by user or the best one we can fit
5383 * in to the sample max size
5385 * - user stack dump data
5387 * - the actual dumped size
5391 perf_output_put(handle, dump_size);
5394 sp = perf_user_stack_pointer(regs);
5395 rem = __output_copy_user(handle, (void *) sp, dump_size);
5396 dyn_size = dump_size - rem;
5398 perf_output_skip(handle, rem);
5401 perf_output_put(handle, dyn_size);
5405 static void __perf_event_header__init_id(struct perf_event_header *header,
5406 struct perf_sample_data *data,
5407 struct perf_event *event)
5409 u64 sample_type = event->attr.sample_type;
5411 data->type = sample_type;
5412 header->size += event->id_header_size;
5414 if (sample_type & PERF_SAMPLE_TID) {
5415 /* namespace issues */
5416 data->tid_entry.pid = perf_event_pid(event, current);
5417 data->tid_entry.tid = perf_event_tid(event, current);
5420 if (sample_type & PERF_SAMPLE_TIME)
5421 data->time = perf_event_clock(event);
5423 if (sample_type & (PERF_SAMPLE_ID | PERF_SAMPLE_IDENTIFIER))
5424 data->id = primary_event_id(event);
5426 if (sample_type & PERF_SAMPLE_STREAM_ID)
5427 data->stream_id = event->id;
5429 if (sample_type & PERF_SAMPLE_CPU) {
5430 data->cpu_entry.cpu = raw_smp_processor_id();
5431 data->cpu_entry.reserved = 0;
5435 void perf_event_header__init_id(struct perf_event_header *header,
5436 struct perf_sample_data *data,
5437 struct perf_event *event)
5439 if (event->attr.sample_id_all)
5440 __perf_event_header__init_id(header, data, event);
5443 static void __perf_event__output_id_sample(struct perf_output_handle *handle,
5444 struct perf_sample_data *data)
5446 u64 sample_type = data->type;
5448 if (sample_type & PERF_SAMPLE_TID)
5449 perf_output_put(handle, data->tid_entry);
5451 if (sample_type & PERF_SAMPLE_TIME)
5452 perf_output_put(handle, data->time);
5454 if (sample_type & PERF_SAMPLE_ID)
5455 perf_output_put(handle, data->id);
5457 if (sample_type & PERF_SAMPLE_STREAM_ID)
5458 perf_output_put(handle, data->stream_id);
5460 if (sample_type & PERF_SAMPLE_CPU)
5461 perf_output_put(handle, data->cpu_entry);
5463 if (sample_type & PERF_SAMPLE_IDENTIFIER)
5464 perf_output_put(handle, data->id);
5467 void perf_event__output_id_sample(struct perf_event *event,
5468 struct perf_output_handle *handle,
5469 struct perf_sample_data *sample)
5471 if (event->attr.sample_id_all)
5472 __perf_event__output_id_sample(handle, sample);
5475 static void perf_output_read_one(struct perf_output_handle *handle,
5476 struct perf_event *event,
5477 u64 enabled, u64 running)
5479 u64 read_format = event->attr.read_format;
5483 values[n++] = perf_event_count(event);
5484 if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED) {
5485 values[n++] = enabled +
5486 atomic64_read(&event->child_total_time_enabled);
5488 if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING) {
5489 values[n++] = running +
5490 atomic64_read(&event->child_total_time_running);
5492 if (read_format & PERF_FORMAT_ID)
5493 values[n++] = primary_event_id(event);
5495 __output_copy(handle, values, n * sizeof(u64));
5499 * XXX PERF_FORMAT_GROUP vs inherited events seems difficult.
5501 static void perf_output_read_group(struct perf_output_handle *handle,
5502 struct perf_event *event,
5503 u64 enabled, u64 running)
5505 struct perf_event *leader = event->group_leader, *sub;
5506 u64 read_format = event->attr.read_format;
5510 values[n++] = 1 + leader->nr_siblings;
5512 if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED)
5513 values[n++] = enabled;
5515 if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING)
5516 values[n++] = running;
5518 if (leader != event)
5519 leader->pmu->read(leader);
5521 values[n++] = perf_event_count(leader);
5522 if (read_format & PERF_FORMAT_ID)
5523 values[n++] = primary_event_id(leader);
5525 __output_copy(handle, values, n * sizeof(u64));
5527 list_for_each_entry(sub, &leader->sibling_list, group_entry) {
5530 if ((sub != event) &&
5531 (sub->state == PERF_EVENT_STATE_ACTIVE))
5532 sub->pmu->read(sub);
5534 values[n++] = perf_event_count(sub);
5535 if (read_format & PERF_FORMAT_ID)
5536 values[n++] = primary_event_id(sub);
5538 __output_copy(handle, values, n * sizeof(u64));
5542 #define PERF_FORMAT_TOTAL_TIMES (PERF_FORMAT_TOTAL_TIME_ENABLED|\
5543 PERF_FORMAT_TOTAL_TIME_RUNNING)
5545 static void perf_output_read(struct perf_output_handle *handle,
5546 struct perf_event *event)
5548 u64 enabled = 0, running = 0, now;
5549 u64 read_format = event->attr.read_format;
5552 * compute total_time_enabled, total_time_running
5553 * based on snapshot values taken when the event
5554 * was last scheduled in.
5556 * we cannot simply called update_context_time()
5557 * because of locking issue as we are called in
5560 if (read_format & PERF_FORMAT_TOTAL_TIMES)
5561 calc_timer_values(event, &now, &enabled, &running);
5563 if (event->attr.read_format & PERF_FORMAT_GROUP)
5564 perf_output_read_group(handle, event, enabled, running);
5566 perf_output_read_one(handle, event, enabled, running);
5569 void perf_output_sample(struct perf_output_handle *handle,
5570 struct perf_event_header *header,
5571 struct perf_sample_data *data,
5572 struct perf_event *event)
5574 u64 sample_type = data->type;
5576 perf_output_put(handle, *header);
5578 if (sample_type & PERF_SAMPLE_IDENTIFIER)
5579 perf_output_put(handle, data->id);
5581 if (sample_type & PERF_SAMPLE_IP)
5582 perf_output_put(handle, data->ip);
5584 if (sample_type & PERF_SAMPLE_TID)
5585 perf_output_put(handle, data->tid_entry);
5587 if (sample_type & PERF_SAMPLE_TIME)
5588 perf_output_put(handle, data->time);
5590 if (sample_type & PERF_SAMPLE_ADDR)
5591 perf_output_put(handle, data->addr);
5593 if (sample_type & PERF_SAMPLE_ID)
5594 perf_output_put(handle, data->id);
5596 if (sample_type & PERF_SAMPLE_STREAM_ID)
5597 perf_output_put(handle, data->stream_id);
5599 if (sample_type & PERF_SAMPLE_CPU)
5600 perf_output_put(handle, data->cpu_entry);
5602 if (sample_type & PERF_SAMPLE_PERIOD)
5603 perf_output_put(handle, data->period);
5605 if (sample_type & PERF_SAMPLE_READ)
5606 perf_output_read(handle, event);
5608 if (sample_type & PERF_SAMPLE_CALLCHAIN) {
5609 if (data->callchain) {
5612 if (data->callchain)
5613 size += data->callchain->nr;
5615 size *= sizeof(u64);
5617 __output_copy(handle, data->callchain, size);
5620 perf_output_put(handle, nr);
5624 if (sample_type & PERF_SAMPLE_RAW) {
5625 struct perf_raw_record *raw = data->raw;
5628 struct perf_raw_frag *frag = &raw->frag;
5630 perf_output_put(handle, raw->size);
5633 __output_custom(handle, frag->copy,
5634 frag->data, frag->size);
5636 __output_copy(handle, frag->data,
5639 if (perf_raw_frag_last(frag))
5644 __output_skip(handle, NULL, frag->pad);
5650 .size = sizeof(u32),
5653 perf_output_put(handle, raw);
5657 if (sample_type & PERF_SAMPLE_BRANCH_STACK) {
5658 if (data->br_stack) {
5661 size = data->br_stack->nr
5662 * sizeof(struct perf_branch_entry);
5664 perf_output_put(handle, data->br_stack->nr);
5665 perf_output_copy(handle, data->br_stack->entries, size);
5668 * we always store at least the value of nr
5671 perf_output_put(handle, nr);
5675 if (sample_type & PERF_SAMPLE_REGS_USER) {
5676 u64 abi = data->regs_user.abi;
5679 * If there are no regs to dump, notice it through
5680 * first u64 being zero (PERF_SAMPLE_REGS_ABI_NONE).
5682 perf_output_put(handle, abi);
5685 u64 mask = event->attr.sample_regs_user;
5686 perf_output_sample_regs(handle,
5687 data->regs_user.regs,
5692 if (sample_type & PERF_SAMPLE_STACK_USER) {
5693 perf_output_sample_ustack(handle,
5694 data->stack_user_size,
5695 data->regs_user.regs);
5698 if (sample_type & PERF_SAMPLE_WEIGHT)
5699 perf_output_put(handle, data->weight);
5701 if (sample_type & PERF_SAMPLE_DATA_SRC)
5702 perf_output_put(handle, data->data_src.val);
5704 if (sample_type & PERF_SAMPLE_TRANSACTION)
5705 perf_output_put(handle, data->txn);
5707 if (sample_type & PERF_SAMPLE_REGS_INTR) {
5708 u64 abi = data->regs_intr.abi;
5710 * If there are no regs to dump, notice it through
5711 * first u64 being zero (PERF_SAMPLE_REGS_ABI_NONE).
5713 perf_output_put(handle, abi);
5716 u64 mask = event->attr.sample_regs_intr;
5718 perf_output_sample_regs(handle,
5719 data->regs_intr.regs,
5724 if (!event->attr.watermark) {
5725 int wakeup_events = event->attr.wakeup_events;
5727 if (wakeup_events) {
5728 struct ring_buffer *rb = handle->rb;
5729 int events = local_inc_return(&rb->events);
5731 if (events >= wakeup_events) {
5732 local_sub(wakeup_events, &rb->events);
5733 local_inc(&rb->wakeup);
5739 void perf_prepare_sample(struct perf_event_header *header,
5740 struct perf_sample_data *data,
5741 struct perf_event *event,
5742 struct pt_regs *regs)
5744 u64 sample_type = event->attr.sample_type;
5746 header->type = PERF_RECORD_SAMPLE;
5747 header->size = sizeof(*header) + event->header_size;
5750 header->misc |= perf_misc_flags(regs);
5752 __perf_event_header__init_id(header, data, event);
5754 if (sample_type & PERF_SAMPLE_IP)
5755 data->ip = perf_instruction_pointer(regs);
5757 if (sample_type & PERF_SAMPLE_CALLCHAIN) {
5760 data->callchain = perf_callchain(event, regs);
5762 if (data->callchain)
5763 size += data->callchain->nr;
5765 header->size += size * sizeof(u64);
5768 if (sample_type & PERF_SAMPLE_RAW) {
5769 struct perf_raw_record *raw = data->raw;
5773 struct perf_raw_frag *frag = &raw->frag;
5778 if (perf_raw_frag_last(frag))
5783 size = round_up(sum + sizeof(u32), sizeof(u64));
5784 raw->size = size - sizeof(u32);
5785 frag->pad = raw->size - sum;
5790 header->size += size;
5793 if (sample_type & PERF_SAMPLE_BRANCH_STACK) {
5794 int size = sizeof(u64); /* nr */
5795 if (data->br_stack) {
5796 size += data->br_stack->nr
5797 * sizeof(struct perf_branch_entry);
5799 header->size += size;
5802 if (sample_type & (PERF_SAMPLE_REGS_USER | PERF_SAMPLE_STACK_USER))
5803 perf_sample_regs_user(&data->regs_user, regs,
5804 &data->regs_user_copy);
5806 if (sample_type & PERF_SAMPLE_REGS_USER) {
5807 /* regs dump ABI info */
5808 int size = sizeof(u64);
5810 if (data->regs_user.regs) {
5811 u64 mask = event->attr.sample_regs_user;
5812 size += hweight64(mask) * sizeof(u64);
5815 header->size += size;
5818 if (sample_type & PERF_SAMPLE_STACK_USER) {
5820 * Either we need PERF_SAMPLE_STACK_USER bit to be allways
5821 * processed as the last one or have additional check added
5822 * in case new sample type is added, because we could eat
5823 * up the rest of the sample size.
5825 u16 stack_size = event->attr.sample_stack_user;
5826 u16 size = sizeof(u64);
5828 stack_size = perf_sample_ustack_size(stack_size, header->size,
5829 data->regs_user.regs);
5832 * If there is something to dump, add space for the dump
5833 * itself and for the field that tells the dynamic size,
5834 * which is how many have been actually dumped.
5837 size += sizeof(u64) + stack_size;
5839 data->stack_user_size = stack_size;
5840 header->size += size;
5843 if (sample_type & PERF_SAMPLE_REGS_INTR) {
5844 /* regs dump ABI info */
5845 int size = sizeof(u64);
5847 perf_sample_regs_intr(&data->regs_intr, regs);
5849 if (data->regs_intr.regs) {
5850 u64 mask = event->attr.sample_regs_intr;
5852 size += hweight64(mask) * sizeof(u64);
5855 header->size += size;
5859 static void __always_inline
5860 __perf_event_output(struct perf_event *event,
5861 struct perf_sample_data *data,
5862 struct pt_regs *regs,
5863 int (*output_begin)(struct perf_output_handle *,
5864 struct perf_event *,
5867 struct perf_output_handle handle;
5868 struct perf_event_header header;
5870 /* protect the callchain buffers */
5873 perf_prepare_sample(&header, data, event, regs);
5875 if (output_begin(&handle, event, header.size))
5878 perf_output_sample(&handle, &header, data, event);
5880 perf_output_end(&handle);
5887 perf_event_output_forward(struct perf_event *event,
5888 struct perf_sample_data *data,
5889 struct pt_regs *regs)
5891 __perf_event_output(event, data, regs, perf_output_begin_forward);
5895 perf_event_output_backward(struct perf_event *event,
5896 struct perf_sample_data *data,
5897 struct pt_regs *regs)
5899 __perf_event_output(event, data, regs, perf_output_begin_backward);
5903 perf_event_output(struct perf_event *event,
5904 struct perf_sample_data *data,
5905 struct pt_regs *regs)
5907 __perf_event_output(event, data, regs, perf_output_begin);
5914 struct perf_read_event {
5915 struct perf_event_header header;
5922 perf_event_read_event(struct perf_event *event,
5923 struct task_struct *task)
5925 struct perf_output_handle handle;
5926 struct perf_sample_data sample;
5927 struct perf_read_event read_event = {
5929 .type = PERF_RECORD_READ,
5931 .size = sizeof(read_event) + event->read_size,
5933 .pid = perf_event_pid(event, task),
5934 .tid = perf_event_tid(event, task),
5938 perf_event_header__init_id(&read_event.header, &sample, event);
5939 ret = perf_output_begin(&handle, event, read_event.header.size);
5943 perf_output_put(&handle, read_event);
5944 perf_output_read(&handle, event);
5945 perf_event__output_id_sample(event, &handle, &sample);
5947 perf_output_end(&handle);
5950 typedef void (perf_iterate_f)(struct perf_event *event, void *data);
5953 perf_iterate_ctx(struct perf_event_context *ctx,
5954 perf_iterate_f output,
5955 void *data, bool all)
5957 struct perf_event *event;
5959 list_for_each_entry_rcu(event, &ctx->event_list, event_entry) {
5961 if (event->state < PERF_EVENT_STATE_INACTIVE)
5963 if (!event_filter_match(event))
5967 output(event, data);
5971 static void perf_iterate_sb_cpu(perf_iterate_f output, void *data)
5973 struct pmu_event_list *pel = this_cpu_ptr(&pmu_sb_events);
5974 struct perf_event *event;
5976 list_for_each_entry_rcu(event, &pel->list, sb_list) {
5978 * Skip events that are not fully formed yet; ensure that
5979 * if we observe event->ctx, both event and ctx will be
5980 * complete enough. See perf_install_in_context().
5982 if (!smp_load_acquire(&event->ctx))
5985 if (event->state < PERF_EVENT_STATE_INACTIVE)
5987 if (!event_filter_match(event))
5989 output(event, data);
5994 * Iterate all events that need to receive side-band events.
5996 * For new callers; ensure that account_pmu_sb_event() includes
5997 * your event, otherwise it might not get delivered.
6000 perf_iterate_sb(perf_iterate_f output, void *data,
6001 struct perf_event_context *task_ctx)
6003 struct perf_event_context *ctx;
6010 * If we have task_ctx != NULL we only notify the task context itself.
6011 * The task_ctx is set only for EXIT events before releasing task
6015 perf_iterate_ctx(task_ctx, output, data, false);
6019 perf_iterate_sb_cpu(output, data);
6021 for_each_task_context_nr(ctxn) {
6022 ctx = rcu_dereference(current->perf_event_ctxp[ctxn]);
6024 perf_iterate_ctx(ctx, output, data, false);
6032 * Clear all file-based filters at exec, they'll have to be
6033 * re-instated when/if these objects are mmapped again.
6035 static void perf_event_addr_filters_exec(struct perf_event *event, void *data)
6037 struct perf_addr_filters_head *ifh = perf_event_addr_filters(event);
6038 struct perf_addr_filter *filter;
6039 unsigned int restart = 0, count = 0;
6040 unsigned long flags;
6042 if (!has_addr_filter(event))
6045 raw_spin_lock_irqsave(&ifh->lock, flags);
6046 list_for_each_entry(filter, &ifh->list, entry) {
6047 if (filter->inode) {
6048 event->addr_filters_offs[count] = 0;
6056 event->addr_filters_gen++;
6057 raw_spin_unlock_irqrestore(&ifh->lock, flags);
6060 perf_event_restart(event);
6063 void perf_event_exec(void)
6065 struct perf_event_context *ctx;
6069 for_each_task_context_nr(ctxn) {
6070 ctx = current->perf_event_ctxp[ctxn];
6074 perf_event_enable_on_exec(ctxn);
6076 perf_iterate_ctx(ctx, perf_event_addr_filters_exec, NULL,
6082 struct remote_output {
6083 struct ring_buffer *rb;
6087 static void __perf_event_output_stop(struct perf_event *event, void *data)
6089 struct perf_event *parent = event->parent;
6090 struct remote_output *ro = data;
6091 struct ring_buffer *rb = ro->rb;
6092 struct stop_event_data sd = {
6096 if (!has_aux(event))
6103 * In case of inheritance, it will be the parent that links to the
6104 * ring-buffer, but it will be the child that's actually using it:
6106 if (rcu_dereference(parent->rb) == rb)
6107 ro->err = __perf_event_stop(&sd);
6110 static int __perf_pmu_output_stop(void *info)
6112 struct perf_event *event = info;
6113 struct pmu *pmu = event->pmu;
6114 struct perf_cpu_context *cpuctx = get_cpu_ptr(pmu->pmu_cpu_context);
6115 struct remote_output ro = {
6120 perf_iterate_ctx(&cpuctx->ctx, __perf_event_output_stop, &ro, false);
6121 if (cpuctx->task_ctx)
6122 perf_iterate_ctx(cpuctx->task_ctx, __perf_event_output_stop,
6129 static void perf_pmu_output_stop(struct perf_event *event)
6131 struct perf_event *iter;
6136 list_for_each_entry_rcu(iter, &event->rb->event_list, rb_entry) {
6138 * For per-CPU events, we need to make sure that neither they
6139 * nor their children are running; for cpu==-1 events it's
6140 * sufficient to stop the event itself if it's active, since
6141 * it can't have children.
6145 cpu = READ_ONCE(iter->oncpu);
6150 err = cpu_function_call(cpu, __perf_pmu_output_stop, event);
6151 if (err == -EAGAIN) {
6160 * task tracking -- fork/exit
6162 * enabled by: attr.comm | attr.mmap | attr.mmap2 | attr.mmap_data | attr.task
6165 struct perf_task_event {
6166 struct task_struct *task;
6167 struct perf_event_context *task_ctx;
6170 struct perf_event_header header;
6180 static int perf_event_task_match(struct perf_event *event)
6182 return event->attr.comm || event->attr.mmap ||
6183 event->attr.mmap2 || event->attr.mmap_data ||
6187 static void perf_event_task_output(struct perf_event *event,
6190 struct perf_task_event *task_event = data;
6191 struct perf_output_handle handle;
6192 struct perf_sample_data sample;
6193 struct task_struct *task = task_event->task;
6194 int ret, size = task_event->event_id.header.size;
6196 if (!perf_event_task_match(event))
6199 perf_event_header__init_id(&task_event->event_id.header, &sample, event);
6201 ret = perf_output_begin(&handle, event,
6202 task_event->event_id.header.size);
6206 task_event->event_id.pid = perf_event_pid(event, task);
6207 task_event->event_id.ppid = perf_event_pid(event, current);
6209 task_event->event_id.tid = perf_event_tid(event, task);
6210 task_event->event_id.ptid = perf_event_tid(event, current);
6212 task_event->event_id.time = perf_event_clock(event);
6214 perf_output_put(&handle, task_event->event_id);
6216 perf_event__output_id_sample(event, &handle, &sample);
6218 perf_output_end(&handle);
6220 task_event->event_id.header.size = size;
6223 static void perf_event_task(struct task_struct *task,
6224 struct perf_event_context *task_ctx,
6227 struct perf_task_event task_event;
6229 if (!atomic_read(&nr_comm_events) &&
6230 !atomic_read(&nr_mmap_events) &&
6231 !atomic_read(&nr_task_events))
6234 task_event = (struct perf_task_event){
6236 .task_ctx = task_ctx,
6239 .type = new ? PERF_RECORD_FORK : PERF_RECORD_EXIT,
6241 .size = sizeof(task_event.event_id),
6251 perf_iterate_sb(perf_event_task_output,
6256 void perf_event_fork(struct task_struct *task)
6258 perf_event_task(task, NULL, 1);
6265 struct perf_comm_event {
6266 struct task_struct *task;
6271 struct perf_event_header header;
6278 static int perf_event_comm_match(struct perf_event *event)
6280 return event->attr.comm;
6283 static void perf_event_comm_output(struct perf_event *event,
6286 struct perf_comm_event *comm_event = data;
6287 struct perf_output_handle handle;
6288 struct perf_sample_data sample;
6289 int size = comm_event->event_id.header.size;
6292 if (!perf_event_comm_match(event))
6295 perf_event_header__init_id(&comm_event->event_id.header, &sample, event);
6296 ret = perf_output_begin(&handle, event,
6297 comm_event->event_id.header.size);
6302 comm_event->event_id.pid = perf_event_pid(event, comm_event->task);
6303 comm_event->event_id.tid = perf_event_tid(event, comm_event->task);
6305 perf_output_put(&handle, comm_event->event_id);
6306 __output_copy(&handle, comm_event->comm,
6307 comm_event->comm_size);
6309 perf_event__output_id_sample(event, &handle, &sample);
6311 perf_output_end(&handle);
6313 comm_event->event_id.header.size = size;
6316 static void perf_event_comm_event(struct perf_comm_event *comm_event)
6318 char comm[TASK_COMM_LEN];
6321 memset(comm, 0, sizeof(comm));
6322 strlcpy(comm, comm_event->task->comm, sizeof(comm));
6323 size = ALIGN(strlen(comm)+1, sizeof(u64));
6325 comm_event->comm = comm;
6326 comm_event->comm_size = size;
6328 comm_event->event_id.header.size = sizeof(comm_event->event_id) + size;
6330 perf_iterate_sb(perf_event_comm_output,
6335 void perf_event_comm(struct task_struct *task, bool exec)
6337 struct perf_comm_event comm_event;
6339 if (!atomic_read(&nr_comm_events))
6342 comm_event = (struct perf_comm_event){
6348 .type = PERF_RECORD_COMM,
6349 .misc = exec ? PERF_RECORD_MISC_COMM_EXEC : 0,
6357 perf_event_comm_event(&comm_event);
6364 struct perf_mmap_event {
6365 struct vm_area_struct *vma;
6367 const char *file_name;
6375 struct perf_event_header header;
6385 static int perf_event_mmap_match(struct perf_event *event,
6388 struct perf_mmap_event *mmap_event = data;
6389 struct vm_area_struct *vma = mmap_event->vma;
6390 int executable = vma->vm_flags & VM_EXEC;
6392 return (!executable && event->attr.mmap_data) ||
6393 (executable && (event->attr.mmap || event->attr.mmap2));
6396 static void perf_event_mmap_output(struct perf_event *event,
6399 struct perf_mmap_event *mmap_event = data;
6400 struct perf_output_handle handle;
6401 struct perf_sample_data sample;
6402 int size = mmap_event->event_id.header.size;
6405 if (!perf_event_mmap_match(event, data))
6408 if (event->attr.mmap2) {
6409 mmap_event->event_id.header.type = PERF_RECORD_MMAP2;
6410 mmap_event->event_id.header.size += sizeof(mmap_event->maj);
6411 mmap_event->event_id.header.size += sizeof(mmap_event->min);
6412 mmap_event->event_id.header.size += sizeof(mmap_event->ino);
6413 mmap_event->event_id.header.size += sizeof(mmap_event->ino_generation);
6414 mmap_event->event_id.header.size += sizeof(mmap_event->prot);
6415 mmap_event->event_id.header.size += sizeof(mmap_event->flags);
6418 perf_event_header__init_id(&mmap_event->event_id.header, &sample, event);
6419 ret = perf_output_begin(&handle, event,
6420 mmap_event->event_id.header.size);
6424 mmap_event->event_id.pid = perf_event_pid(event, current);
6425 mmap_event->event_id.tid = perf_event_tid(event, current);
6427 perf_output_put(&handle, mmap_event->event_id);
6429 if (event->attr.mmap2) {
6430 perf_output_put(&handle, mmap_event->maj);
6431 perf_output_put(&handle, mmap_event->min);
6432 perf_output_put(&handle, mmap_event->ino);
6433 perf_output_put(&handle, mmap_event->ino_generation);
6434 perf_output_put(&handle, mmap_event->prot);
6435 perf_output_put(&handle, mmap_event->flags);
6438 __output_copy(&handle, mmap_event->file_name,
6439 mmap_event->file_size);
6441 perf_event__output_id_sample(event, &handle, &sample);
6443 perf_output_end(&handle);
6445 mmap_event->event_id.header.size = size;
6448 static void perf_event_mmap_event(struct perf_mmap_event *mmap_event)
6450 struct vm_area_struct *vma = mmap_event->vma;
6451 struct file *file = vma->vm_file;
6452 int maj = 0, min = 0;
6453 u64 ino = 0, gen = 0;
6454 u32 prot = 0, flags = 0;
6461 struct inode *inode;
6464 buf = kmalloc(PATH_MAX, GFP_KERNEL);
6470 * d_path() works from the end of the rb backwards, so we
6471 * need to add enough zero bytes after the string to handle
6472 * the 64bit alignment we do later.
6474 name = file_path(file, buf, PATH_MAX - sizeof(u64));
6479 inode = file_inode(vma->vm_file);
6480 dev = inode->i_sb->s_dev;
6482 gen = inode->i_generation;
6486 if (vma->vm_flags & VM_READ)
6488 if (vma->vm_flags & VM_WRITE)
6490 if (vma->vm_flags & VM_EXEC)
6493 if (vma->vm_flags & VM_MAYSHARE)
6496 flags = MAP_PRIVATE;
6498 if (vma->vm_flags & VM_DENYWRITE)
6499 flags |= MAP_DENYWRITE;
6500 if (vma->vm_flags & VM_MAYEXEC)
6501 flags |= MAP_EXECUTABLE;
6502 if (vma->vm_flags & VM_LOCKED)
6503 flags |= MAP_LOCKED;
6504 if (vma->vm_flags & VM_HUGETLB)
6505 flags |= MAP_HUGETLB;
6509 if (vma->vm_ops && vma->vm_ops->name) {
6510 name = (char *) vma->vm_ops->name(vma);
6515 name = (char *)arch_vma_name(vma);
6519 if (vma->vm_start <= vma->vm_mm->start_brk &&
6520 vma->vm_end >= vma->vm_mm->brk) {
6524 if (vma->vm_start <= vma->vm_mm->start_stack &&
6525 vma->vm_end >= vma->vm_mm->start_stack) {
6535 strlcpy(tmp, name, sizeof(tmp));
6539 * Since our buffer works in 8 byte units we need to align our string
6540 * size to a multiple of 8. However, we must guarantee the tail end is
6541 * zero'd out to avoid leaking random bits to userspace.
6543 size = strlen(name)+1;
6544 while (!IS_ALIGNED(size, sizeof(u64)))
6545 name[size++] = '\0';
6547 mmap_event->file_name = name;
6548 mmap_event->file_size = size;
6549 mmap_event->maj = maj;
6550 mmap_event->min = min;
6551 mmap_event->ino = ino;
6552 mmap_event->ino_generation = gen;
6553 mmap_event->prot = prot;
6554 mmap_event->flags = flags;
6556 if (!(vma->vm_flags & VM_EXEC))
6557 mmap_event->event_id.header.misc |= PERF_RECORD_MISC_MMAP_DATA;
6559 mmap_event->event_id.header.size = sizeof(mmap_event->event_id) + size;
6561 perf_iterate_sb(perf_event_mmap_output,
6569 * Whether this @filter depends on a dynamic object which is not loaded
6570 * yet or its load addresses are not known.
6572 static bool perf_addr_filter_needs_mmap(struct perf_addr_filter *filter)
6574 return filter->filter && filter->inode;
6578 * Check whether inode and address range match filter criteria.
6580 static bool perf_addr_filter_match(struct perf_addr_filter *filter,
6581 struct file *file, unsigned long offset,
6584 if (filter->inode != file->f_inode)
6587 if (filter->offset > offset + size)
6590 if (filter->offset + filter->size < offset)
6596 static void __perf_addr_filters_adjust(struct perf_event *event, void *data)
6598 struct perf_addr_filters_head *ifh = perf_event_addr_filters(event);
6599 struct vm_area_struct *vma = data;
6600 unsigned long off = vma->vm_pgoff << PAGE_SHIFT, flags;
6601 struct file *file = vma->vm_file;
6602 struct perf_addr_filter *filter;
6603 unsigned int restart = 0, count = 0;
6605 if (!has_addr_filter(event))
6611 raw_spin_lock_irqsave(&ifh->lock, flags);
6612 list_for_each_entry(filter, &ifh->list, entry) {
6613 if (perf_addr_filter_match(filter, file, off,
6614 vma->vm_end - vma->vm_start)) {
6615 event->addr_filters_offs[count] = vma->vm_start;
6623 event->addr_filters_gen++;
6624 raw_spin_unlock_irqrestore(&ifh->lock, flags);
6627 perf_event_restart(event);
6631 * Adjust all task's events' filters to the new vma
6633 static void perf_addr_filters_adjust(struct vm_area_struct *vma)
6635 struct perf_event_context *ctx;
6639 for_each_task_context_nr(ctxn) {
6640 ctx = rcu_dereference(current->perf_event_ctxp[ctxn]);
6644 perf_iterate_ctx(ctx, __perf_addr_filters_adjust, vma, true);
6649 void perf_event_mmap(struct vm_area_struct *vma)
6651 struct perf_mmap_event mmap_event;
6653 if (!atomic_read(&nr_mmap_events))
6656 mmap_event = (struct perf_mmap_event){
6662 .type = PERF_RECORD_MMAP,
6663 .misc = PERF_RECORD_MISC_USER,
6668 .start = vma->vm_start,
6669 .len = vma->vm_end - vma->vm_start,
6670 .pgoff = (u64)vma->vm_pgoff << PAGE_SHIFT,
6672 /* .maj (attr_mmap2 only) */
6673 /* .min (attr_mmap2 only) */
6674 /* .ino (attr_mmap2 only) */
6675 /* .ino_generation (attr_mmap2 only) */
6676 /* .prot (attr_mmap2 only) */
6677 /* .flags (attr_mmap2 only) */
6680 perf_addr_filters_adjust(vma);
6681 perf_event_mmap_event(&mmap_event);
6684 void perf_event_aux_event(struct perf_event *event, unsigned long head,
6685 unsigned long size, u64 flags)
6687 struct perf_output_handle handle;
6688 struct perf_sample_data sample;
6689 struct perf_aux_event {
6690 struct perf_event_header header;
6696 .type = PERF_RECORD_AUX,
6698 .size = sizeof(rec),
6706 perf_event_header__init_id(&rec.header, &sample, event);
6707 ret = perf_output_begin(&handle, event, rec.header.size);
6712 perf_output_put(&handle, rec);
6713 perf_event__output_id_sample(event, &handle, &sample);
6715 perf_output_end(&handle);
6719 * Lost/dropped samples logging
6721 void perf_log_lost_samples(struct perf_event *event, u64 lost)
6723 struct perf_output_handle handle;
6724 struct perf_sample_data sample;
6728 struct perf_event_header header;
6730 } lost_samples_event = {
6732 .type = PERF_RECORD_LOST_SAMPLES,
6734 .size = sizeof(lost_samples_event),
6739 perf_event_header__init_id(&lost_samples_event.header, &sample, event);
6741 ret = perf_output_begin(&handle, event,
6742 lost_samples_event.header.size);
6746 perf_output_put(&handle, lost_samples_event);
6747 perf_event__output_id_sample(event, &handle, &sample);
6748 perf_output_end(&handle);
6752 * context_switch tracking
6755 struct perf_switch_event {
6756 struct task_struct *task;
6757 struct task_struct *next_prev;
6760 struct perf_event_header header;
6766 static int perf_event_switch_match(struct perf_event *event)
6768 return event->attr.context_switch;
6771 static void perf_event_switch_output(struct perf_event *event, void *data)
6773 struct perf_switch_event *se = data;
6774 struct perf_output_handle handle;
6775 struct perf_sample_data sample;
6778 if (!perf_event_switch_match(event))
6781 /* Only CPU-wide events are allowed to see next/prev pid/tid */
6782 if (event->ctx->task) {
6783 se->event_id.header.type = PERF_RECORD_SWITCH;
6784 se->event_id.header.size = sizeof(se->event_id.header);
6786 se->event_id.header.type = PERF_RECORD_SWITCH_CPU_WIDE;
6787 se->event_id.header.size = sizeof(se->event_id);
6788 se->event_id.next_prev_pid =
6789 perf_event_pid(event, se->next_prev);
6790 se->event_id.next_prev_tid =
6791 perf_event_tid(event, se->next_prev);
6794 perf_event_header__init_id(&se->event_id.header, &sample, event);
6796 ret = perf_output_begin(&handle, event, se->event_id.header.size);
6800 if (event->ctx->task)
6801 perf_output_put(&handle, se->event_id.header);
6803 perf_output_put(&handle, se->event_id);
6805 perf_event__output_id_sample(event, &handle, &sample);
6807 perf_output_end(&handle);
6810 static void perf_event_switch(struct task_struct *task,
6811 struct task_struct *next_prev, bool sched_in)
6813 struct perf_switch_event switch_event;
6815 /* N.B. caller checks nr_switch_events != 0 */
6817 switch_event = (struct perf_switch_event){
6819 .next_prev = next_prev,
6823 .misc = sched_in ? 0 : PERF_RECORD_MISC_SWITCH_OUT,
6826 /* .next_prev_pid */
6827 /* .next_prev_tid */
6831 perf_iterate_sb(perf_event_switch_output,
6837 * IRQ throttle logging
6840 static void perf_log_throttle(struct perf_event *event, int enable)
6842 struct perf_output_handle handle;
6843 struct perf_sample_data sample;
6847 struct perf_event_header header;
6851 } throttle_event = {
6853 .type = PERF_RECORD_THROTTLE,
6855 .size = sizeof(throttle_event),
6857 .time = perf_event_clock(event),
6858 .id = primary_event_id(event),
6859 .stream_id = event->id,
6863 throttle_event.header.type = PERF_RECORD_UNTHROTTLE;
6865 perf_event_header__init_id(&throttle_event.header, &sample, event);
6867 ret = perf_output_begin(&handle, event,
6868 throttle_event.header.size);
6872 perf_output_put(&handle, throttle_event);
6873 perf_event__output_id_sample(event, &handle, &sample);
6874 perf_output_end(&handle);
6877 static void perf_log_itrace_start(struct perf_event *event)
6879 struct perf_output_handle handle;
6880 struct perf_sample_data sample;
6881 struct perf_aux_event {
6882 struct perf_event_header header;
6889 event = event->parent;
6891 if (!(event->pmu->capabilities & PERF_PMU_CAP_ITRACE) ||
6892 event->hw.itrace_started)
6895 rec.header.type = PERF_RECORD_ITRACE_START;
6896 rec.header.misc = 0;
6897 rec.header.size = sizeof(rec);
6898 rec.pid = perf_event_pid(event, current);
6899 rec.tid = perf_event_tid(event, current);
6901 perf_event_header__init_id(&rec.header, &sample, event);
6902 ret = perf_output_begin(&handle, event, rec.header.size);
6907 perf_output_put(&handle, rec);
6908 perf_event__output_id_sample(event, &handle, &sample);
6910 perf_output_end(&handle);
6914 * Generic event overflow handling, sampling.
6917 static int __perf_event_overflow(struct perf_event *event,
6918 int throttle, struct perf_sample_data *data,
6919 struct pt_regs *regs)
6921 int events = atomic_read(&event->event_limit);
6922 struct hw_perf_event *hwc = &event->hw;
6927 * Non-sampling counters might still use the PMI to fold short
6928 * hardware counters, ignore those.
6930 if (unlikely(!is_sampling_event(event)))
6933 seq = __this_cpu_read(perf_throttled_seq);
6934 if (seq != hwc->interrupts_seq) {
6935 hwc->interrupts_seq = seq;
6936 hwc->interrupts = 1;
6939 if (unlikely(throttle
6940 && hwc->interrupts >= max_samples_per_tick)) {
6941 __this_cpu_inc(perf_throttled_count);
6942 tick_dep_set_cpu(smp_processor_id(), TICK_DEP_BIT_PERF_EVENTS);
6943 hwc->interrupts = MAX_INTERRUPTS;
6944 perf_log_throttle(event, 0);
6949 if (event->attr.freq) {
6950 u64 now = perf_clock();
6951 s64 delta = now - hwc->freq_time_stamp;
6953 hwc->freq_time_stamp = now;
6955 if (delta > 0 && delta < 2*TICK_NSEC)
6956 perf_adjust_period(event, delta, hwc->last_period, true);
6960 * XXX event_limit might not quite work as expected on inherited
6964 event->pending_kill = POLL_IN;
6965 if (events && atomic_dec_and_test(&event->event_limit)) {
6967 event->pending_kill = POLL_HUP;
6968 event->pending_disable = 1;
6969 irq_work_queue(&event->pending);
6972 event->overflow_handler(event, data, regs);
6974 if (*perf_event_fasync(event) && event->pending_kill) {
6975 event->pending_wakeup = 1;
6976 irq_work_queue(&event->pending);
6982 int perf_event_overflow(struct perf_event *event,
6983 struct perf_sample_data *data,
6984 struct pt_regs *regs)
6986 return __perf_event_overflow(event, 1, data, regs);
6990 * Generic software event infrastructure
6993 struct swevent_htable {
6994 struct swevent_hlist *swevent_hlist;
6995 struct mutex hlist_mutex;
6998 /* Recursion avoidance in each contexts */
6999 int recursion[PERF_NR_CONTEXTS];
7002 static DEFINE_PER_CPU(struct swevent_htable, swevent_htable);
7005 * We directly increment event->count and keep a second value in
7006 * event->hw.period_left to count intervals. This period event
7007 * is kept in the range [-sample_period, 0] so that we can use the
7011 u64 perf_swevent_set_period(struct perf_event *event)
7013 struct hw_perf_event *hwc = &event->hw;
7014 u64 period = hwc->last_period;
7018 hwc->last_period = hwc->sample_period;
7021 old = val = local64_read(&hwc->period_left);
7025 nr = div64_u64(period + val, period);
7026 offset = nr * period;
7028 if (local64_cmpxchg(&hwc->period_left, old, val) != old)
7034 static void perf_swevent_overflow(struct perf_event *event, u64 overflow,
7035 struct perf_sample_data *data,
7036 struct pt_regs *regs)
7038 struct hw_perf_event *hwc = &event->hw;
7042 overflow = perf_swevent_set_period(event);
7044 if (hwc->interrupts == MAX_INTERRUPTS)
7047 for (; overflow; overflow--) {
7048 if (__perf_event_overflow(event, throttle,
7051 * We inhibit the overflow from happening when
7052 * hwc->interrupts == MAX_INTERRUPTS.
7060 static void perf_swevent_event(struct perf_event *event, u64 nr,
7061 struct perf_sample_data *data,
7062 struct pt_regs *regs)
7064 struct hw_perf_event *hwc = &event->hw;
7066 local64_add(nr, &event->count);
7071 if (!is_sampling_event(event))
7074 if ((event->attr.sample_type & PERF_SAMPLE_PERIOD) && !event->attr.freq) {
7076 return perf_swevent_overflow(event, 1, data, regs);
7078 data->period = event->hw.last_period;
7080 if (nr == 1 && hwc->sample_period == 1 && !event->attr.freq)
7081 return perf_swevent_overflow(event, 1, data, regs);
7083 if (local64_add_negative(nr, &hwc->period_left))
7086 perf_swevent_overflow(event, 0, data, regs);
7089 static int perf_exclude_event(struct perf_event *event,
7090 struct pt_regs *regs)
7092 if (event->hw.state & PERF_HES_STOPPED)
7096 if (event->attr.exclude_user && user_mode(regs))
7099 if (event->attr.exclude_kernel && !user_mode(regs))
7106 static int perf_swevent_match(struct perf_event *event,
7107 enum perf_type_id type,
7109 struct perf_sample_data *data,
7110 struct pt_regs *regs)
7112 if (event->attr.type != type)
7115 if (event->attr.config != event_id)
7118 if (perf_exclude_event(event, regs))
7124 static inline u64 swevent_hash(u64 type, u32 event_id)
7126 u64 val = event_id | (type << 32);
7128 return hash_64(val, SWEVENT_HLIST_BITS);
7131 static inline struct hlist_head *
7132 __find_swevent_head(struct swevent_hlist *hlist, u64 type, u32 event_id)
7134 u64 hash = swevent_hash(type, event_id);
7136 return &hlist->heads[hash];
7139 /* For the read side: events when they trigger */
7140 static inline struct hlist_head *
7141 find_swevent_head_rcu(struct swevent_htable *swhash, u64 type, u32 event_id)
7143 struct swevent_hlist *hlist;
7145 hlist = rcu_dereference(swhash->swevent_hlist);
7149 return __find_swevent_head(hlist, type, event_id);
7152 /* For the event head insertion and removal in the hlist */
7153 static inline struct hlist_head *
7154 find_swevent_head(struct swevent_htable *swhash, struct perf_event *event)
7156 struct swevent_hlist *hlist;
7157 u32 event_id = event->attr.config;
7158 u64 type = event->attr.type;
7161 * Event scheduling is always serialized against hlist allocation
7162 * and release. Which makes the protected version suitable here.
7163 * The context lock guarantees that.
7165 hlist = rcu_dereference_protected(swhash->swevent_hlist,
7166 lockdep_is_held(&event->ctx->lock));
7170 return __find_swevent_head(hlist, type, event_id);
7173 static void do_perf_sw_event(enum perf_type_id type, u32 event_id,
7175 struct perf_sample_data *data,
7176 struct pt_regs *regs)
7178 struct swevent_htable *swhash = this_cpu_ptr(&swevent_htable);
7179 struct perf_event *event;
7180 struct hlist_head *head;
7183 head = find_swevent_head_rcu(swhash, type, event_id);
7187 hlist_for_each_entry_rcu(event, head, hlist_entry) {
7188 if (perf_swevent_match(event, type, event_id, data, regs))
7189 perf_swevent_event(event, nr, data, regs);
7195 DEFINE_PER_CPU(struct pt_regs, __perf_regs[4]);
7197 int perf_swevent_get_recursion_context(void)
7199 struct swevent_htable *swhash = this_cpu_ptr(&swevent_htable);
7201 return get_recursion_context(swhash->recursion);
7203 EXPORT_SYMBOL_GPL(perf_swevent_get_recursion_context);
7205 void perf_swevent_put_recursion_context(int rctx)
7207 struct swevent_htable *swhash = this_cpu_ptr(&swevent_htable);
7209 put_recursion_context(swhash->recursion, rctx);
7212 void ___perf_sw_event(u32 event_id, u64 nr, struct pt_regs *regs, u64 addr)
7214 struct perf_sample_data data;
7216 if (WARN_ON_ONCE(!regs))
7219 perf_sample_data_init(&data, addr, 0);
7220 do_perf_sw_event(PERF_TYPE_SOFTWARE, event_id, nr, &data, regs);
7223 void __perf_sw_event(u32 event_id, u64 nr, struct pt_regs *regs, u64 addr)
7227 preempt_disable_notrace();
7228 rctx = perf_swevent_get_recursion_context();
7229 if (unlikely(rctx < 0))
7232 ___perf_sw_event(event_id, nr, regs, addr);
7234 perf_swevent_put_recursion_context(rctx);
7236 preempt_enable_notrace();
7239 static void perf_swevent_read(struct perf_event *event)
7243 static int perf_swevent_add(struct perf_event *event, int flags)
7245 struct swevent_htable *swhash = this_cpu_ptr(&swevent_htable);
7246 struct hw_perf_event *hwc = &event->hw;
7247 struct hlist_head *head;
7249 if (is_sampling_event(event)) {
7250 hwc->last_period = hwc->sample_period;
7251 perf_swevent_set_period(event);
7254 hwc->state = !(flags & PERF_EF_START);
7256 head = find_swevent_head(swhash, event);
7257 if (WARN_ON_ONCE(!head))
7260 hlist_add_head_rcu(&event->hlist_entry, head);
7261 perf_event_update_userpage(event);
7266 static void perf_swevent_del(struct perf_event *event, int flags)
7268 hlist_del_rcu(&event->hlist_entry);
7271 static void perf_swevent_start(struct perf_event *event, int flags)
7273 event->hw.state = 0;
7276 static void perf_swevent_stop(struct perf_event *event, int flags)
7278 event->hw.state = PERF_HES_STOPPED;
7281 /* Deref the hlist from the update side */
7282 static inline struct swevent_hlist *
7283 swevent_hlist_deref(struct swevent_htable *swhash)
7285 return rcu_dereference_protected(swhash->swevent_hlist,
7286 lockdep_is_held(&swhash->hlist_mutex));
7289 static void swevent_hlist_release(struct swevent_htable *swhash)
7291 struct swevent_hlist *hlist = swevent_hlist_deref(swhash);
7296 RCU_INIT_POINTER(swhash->swevent_hlist, NULL);
7297 kfree_rcu(hlist, rcu_head);
7300 static void swevent_hlist_put_cpu(int cpu)
7302 struct swevent_htable *swhash = &per_cpu(swevent_htable, cpu);
7304 mutex_lock(&swhash->hlist_mutex);
7306 if (!--swhash->hlist_refcount)
7307 swevent_hlist_release(swhash);
7309 mutex_unlock(&swhash->hlist_mutex);
7312 static void swevent_hlist_put(void)
7316 for_each_possible_cpu(cpu)
7317 swevent_hlist_put_cpu(cpu);
7320 static int swevent_hlist_get_cpu(int cpu)
7322 struct swevent_htable *swhash = &per_cpu(swevent_htable, cpu);
7325 mutex_lock(&swhash->hlist_mutex);
7326 if (!swevent_hlist_deref(swhash) && cpu_online(cpu)) {
7327 struct swevent_hlist *hlist;
7329 hlist = kzalloc(sizeof(*hlist), GFP_KERNEL);
7334 rcu_assign_pointer(swhash->swevent_hlist, hlist);
7336 swhash->hlist_refcount++;
7338 mutex_unlock(&swhash->hlist_mutex);
7343 static int swevent_hlist_get(void)
7345 int err, cpu, failed_cpu;
7348 for_each_possible_cpu(cpu) {
7349 err = swevent_hlist_get_cpu(cpu);
7359 for_each_possible_cpu(cpu) {
7360 if (cpu == failed_cpu)
7362 swevent_hlist_put_cpu(cpu);
7369 struct static_key perf_swevent_enabled[PERF_COUNT_SW_MAX];
7371 static void sw_perf_event_destroy(struct perf_event *event)
7373 u64 event_id = event->attr.config;
7375 WARN_ON(event->parent);
7377 static_key_slow_dec(&perf_swevent_enabled[event_id]);
7378 swevent_hlist_put();
7381 static int perf_swevent_init(struct perf_event *event)
7383 u64 event_id = event->attr.config;
7385 if (event->attr.type != PERF_TYPE_SOFTWARE)
7389 * no branch sampling for software events
7391 if (has_branch_stack(event))
7395 case PERF_COUNT_SW_CPU_CLOCK:
7396 case PERF_COUNT_SW_TASK_CLOCK:
7403 if (event_id >= PERF_COUNT_SW_MAX)
7406 if (!event->parent) {
7409 err = swevent_hlist_get();
7413 static_key_slow_inc(&perf_swevent_enabled[event_id]);
7414 event->destroy = sw_perf_event_destroy;
7420 static struct pmu perf_swevent = {
7421 .task_ctx_nr = perf_sw_context,
7423 .capabilities = PERF_PMU_CAP_NO_NMI,
7425 .event_init = perf_swevent_init,
7426 .add = perf_swevent_add,
7427 .del = perf_swevent_del,
7428 .start = perf_swevent_start,
7429 .stop = perf_swevent_stop,
7430 .read = perf_swevent_read,
7433 #ifdef CONFIG_EVENT_TRACING
7435 static int perf_tp_filter_match(struct perf_event *event,
7436 struct perf_sample_data *data)
7438 void *record = data->raw->frag.data;
7440 /* only top level events have filters set */
7442 event = event->parent;
7444 if (likely(!event->filter) || filter_match_preds(event->filter, record))
7449 static int perf_tp_event_match(struct perf_event *event,
7450 struct perf_sample_data *data,
7451 struct pt_regs *regs)
7453 if (event->hw.state & PERF_HES_STOPPED)
7456 * All tracepoints are from kernel-space.
7458 if (event->attr.exclude_kernel)
7461 if (!perf_tp_filter_match(event, data))
7467 void perf_trace_run_bpf_submit(void *raw_data, int size, int rctx,
7468 struct trace_event_call *call, u64 count,
7469 struct pt_regs *regs, struct hlist_head *head,
7470 struct task_struct *task)
7472 struct bpf_prog *prog = call->prog;
7475 *(struct pt_regs **)raw_data = regs;
7476 if (!trace_call_bpf(prog, raw_data) || hlist_empty(head)) {
7477 perf_swevent_put_recursion_context(rctx);
7481 perf_tp_event(call->event.type, count, raw_data, size, regs, head,
7484 EXPORT_SYMBOL_GPL(perf_trace_run_bpf_submit);
7486 void perf_tp_event(u16 event_type, u64 count, void *record, int entry_size,
7487 struct pt_regs *regs, struct hlist_head *head, int rctx,
7488 struct task_struct *task)
7490 struct perf_sample_data data;
7491 struct perf_event *event;
7493 struct perf_raw_record raw = {
7500 perf_sample_data_init(&data, 0, 0);
7503 perf_trace_buf_update(record, event_type);
7505 hlist_for_each_entry_rcu(event, head, hlist_entry) {
7506 if (perf_tp_event_match(event, &data, regs))
7507 perf_swevent_event(event, count, &data, regs);
7511 * If we got specified a target task, also iterate its context and
7512 * deliver this event there too.
7514 if (task && task != current) {
7515 struct perf_event_context *ctx;
7516 struct trace_entry *entry = record;
7519 ctx = rcu_dereference(task->perf_event_ctxp[perf_sw_context]);
7523 list_for_each_entry_rcu(event, &ctx->event_list, event_entry) {
7524 if (event->attr.type != PERF_TYPE_TRACEPOINT)
7526 if (event->attr.config != entry->type)
7528 if (perf_tp_event_match(event, &data, regs))
7529 perf_swevent_event(event, count, &data, regs);
7535 perf_swevent_put_recursion_context(rctx);
7537 EXPORT_SYMBOL_GPL(perf_tp_event);
7539 static void tp_perf_event_destroy(struct perf_event *event)
7541 perf_trace_destroy(event);
7544 static int perf_tp_event_init(struct perf_event *event)
7548 if (event->attr.type != PERF_TYPE_TRACEPOINT)
7552 * no branch sampling for tracepoint events
7554 if (has_branch_stack(event))
7557 err = perf_trace_init(event);
7561 event->destroy = tp_perf_event_destroy;
7566 static struct pmu perf_tracepoint = {
7567 .task_ctx_nr = perf_sw_context,
7569 .event_init = perf_tp_event_init,
7570 .add = perf_trace_add,
7571 .del = perf_trace_del,
7572 .start = perf_swevent_start,
7573 .stop = perf_swevent_stop,
7574 .read = perf_swevent_read,
7577 static inline void perf_tp_register(void)
7579 perf_pmu_register(&perf_tracepoint, "tracepoint", PERF_TYPE_TRACEPOINT);
7582 static void perf_event_free_filter(struct perf_event *event)
7584 ftrace_profile_free_filter(event);
7587 static int perf_event_set_bpf_prog(struct perf_event *event, u32 prog_fd)
7589 bool is_kprobe, is_tracepoint;
7590 struct bpf_prog *prog;
7592 if (event->attr.type != PERF_TYPE_TRACEPOINT)
7595 if (event->tp_event->prog)
7598 is_kprobe = event->tp_event->flags & TRACE_EVENT_FL_UKPROBE;
7599 is_tracepoint = event->tp_event->flags & TRACE_EVENT_FL_TRACEPOINT;
7600 if (!is_kprobe && !is_tracepoint)
7601 /* bpf programs can only be attached to u/kprobe or tracepoint */
7604 prog = bpf_prog_get(prog_fd);
7606 return PTR_ERR(prog);
7608 if ((is_kprobe && prog->type != BPF_PROG_TYPE_KPROBE) ||
7609 (is_tracepoint && prog->type != BPF_PROG_TYPE_TRACEPOINT)) {
7610 /* valid fd, but invalid bpf program type */
7615 if (is_tracepoint) {
7616 int off = trace_event_get_offsets(event->tp_event);
7618 if (prog->aux->max_ctx_offset > off) {
7623 event->tp_event->prog = prog;
7628 static void perf_event_free_bpf_prog(struct perf_event *event)
7630 struct bpf_prog *prog;
7632 if (!event->tp_event)
7635 prog = event->tp_event->prog;
7637 event->tp_event->prog = NULL;
7644 static inline void perf_tp_register(void)
7648 static void perf_event_free_filter(struct perf_event *event)
7652 static int perf_event_set_bpf_prog(struct perf_event *event, u32 prog_fd)
7657 static void perf_event_free_bpf_prog(struct perf_event *event)
7660 #endif /* CONFIG_EVENT_TRACING */
7662 #ifdef CONFIG_HAVE_HW_BREAKPOINT
7663 void perf_bp_event(struct perf_event *bp, void *data)
7665 struct perf_sample_data sample;
7666 struct pt_regs *regs = data;
7668 perf_sample_data_init(&sample, bp->attr.bp_addr, 0);
7670 if (!bp->hw.state && !perf_exclude_event(bp, regs))
7671 perf_swevent_event(bp, 1, &sample, regs);
7676 * Allocate a new address filter
7678 static struct perf_addr_filter *
7679 perf_addr_filter_new(struct perf_event *event, struct list_head *filters)
7681 int node = cpu_to_node(event->cpu == -1 ? 0 : event->cpu);
7682 struct perf_addr_filter *filter;
7684 filter = kzalloc_node(sizeof(*filter), GFP_KERNEL, node);
7688 INIT_LIST_HEAD(&filter->entry);
7689 list_add_tail(&filter->entry, filters);
7694 static void free_filters_list(struct list_head *filters)
7696 struct perf_addr_filter *filter, *iter;
7698 list_for_each_entry_safe(filter, iter, filters, entry) {
7700 iput(filter->inode);
7701 list_del(&filter->entry);
7707 * Free existing address filters and optionally install new ones
7709 static void perf_addr_filters_splice(struct perf_event *event,
7710 struct list_head *head)
7712 unsigned long flags;
7715 if (!has_addr_filter(event))
7718 /* don't bother with children, they don't have their own filters */
7722 raw_spin_lock_irqsave(&event->addr_filters.lock, flags);
7724 list_splice_init(&event->addr_filters.list, &list);
7726 list_splice(head, &event->addr_filters.list);
7728 raw_spin_unlock_irqrestore(&event->addr_filters.lock, flags);
7730 free_filters_list(&list);
7734 * Scan through mm's vmas and see if one of them matches the
7735 * @filter; if so, adjust filter's address range.
7736 * Called with mm::mmap_sem down for reading.
7738 static unsigned long perf_addr_filter_apply(struct perf_addr_filter *filter,
7739 struct mm_struct *mm)
7741 struct vm_area_struct *vma;
7743 for (vma = mm->mmap; vma; vma = vma->vm_next) {
7744 struct file *file = vma->vm_file;
7745 unsigned long off = vma->vm_pgoff << PAGE_SHIFT;
7746 unsigned long vma_size = vma->vm_end - vma->vm_start;
7751 if (!perf_addr_filter_match(filter, file, off, vma_size))
7754 return vma->vm_start;
7761 * Update event's address range filters based on the
7762 * task's existing mappings, if any.
7764 static void perf_event_addr_filters_apply(struct perf_event *event)
7766 struct perf_addr_filters_head *ifh = perf_event_addr_filters(event);
7767 struct task_struct *task = READ_ONCE(event->ctx->task);
7768 struct perf_addr_filter *filter;
7769 struct mm_struct *mm = NULL;
7770 unsigned int count = 0;
7771 unsigned long flags;
7774 * We may observe TASK_TOMBSTONE, which means that the event tear-down
7775 * will stop on the parent's child_mutex that our caller is also holding
7777 if (task == TASK_TOMBSTONE)
7780 mm = get_task_mm(event->ctx->task);
7784 down_read(&mm->mmap_sem);
7786 raw_spin_lock_irqsave(&ifh->lock, flags);
7787 list_for_each_entry(filter, &ifh->list, entry) {
7788 event->addr_filters_offs[count] = 0;
7790 if (perf_addr_filter_needs_mmap(filter))
7791 event->addr_filters_offs[count] =
7792 perf_addr_filter_apply(filter, mm);
7797 event->addr_filters_gen++;
7798 raw_spin_unlock_irqrestore(&ifh->lock, flags);
7800 up_read(&mm->mmap_sem);
7805 perf_event_restart(event);
7809 * Address range filtering: limiting the data to certain
7810 * instruction address ranges. Filters are ioctl()ed to us from
7811 * userspace as ascii strings.
7813 * Filter string format:
7816 * where ACTION is one of the
7817 * * "filter": limit the trace to this region
7818 * * "start": start tracing from this address
7819 * * "stop": stop tracing at this address/region;
7821 * * for kernel addresses: <start address>[/<size>]
7822 * * for object files: <start address>[/<size>]@</path/to/object/file>
7824 * if <size> is not specified, the range is treated as a single address.
7837 IF_STATE_ACTION = 0,
7842 static const match_table_t if_tokens = {
7843 { IF_ACT_FILTER, "filter" },
7844 { IF_ACT_START, "start" },
7845 { IF_ACT_STOP, "stop" },
7846 { IF_SRC_FILE, "%u/%u@%s" },
7847 { IF_SRC_KERNEL, "%u/%u" },
7848 { IF_SRC_FILEADDR, "%u@%s" },
7849 { IF_SRC_KERNELADDR, "%u" },
7853 * Address filter string parser
7856 perf_event_parse_addr_filter(struct perf_event *event, char *fstr,
7857 struct list_head *filters)
7859 struct perf_addr_filter *filter = NULL;
7860 char *start, *orig, *filename = NULL;
7862 substring_t args[MAX_OPT_ARGS];
7863 int state = IF_STATE_ACTION, token;
7864 unsigned int kernel = 0;
7867 orig = fstr = kstrdup(fstr, GFP_KERNEL);
7871 while ((start = strsep(&fstr, " ,\n")) != NULL) {
7877 /* filter definition begins */
7878 if (state == IF_STATE_ACTION) {
7879 filter = perf_addr_filter_new(event, filters);
7884 token = match_token(start, if_tokens, args);
7891 if (state != IF_STATE_ACTION)
7894 state = IF_STATE_SOURCE;
7897 case IF_SRC_KERNELADDR:
7901 case IF_SRC_FILEADDR:
7903 if (state != IF_STATE_SOURCE)
7906 if (token == IF_SRC_FILE || token == IF_SRC_KERNEL)
7910 ret = kstrtoul(args[0].from, 0, &filter->offset);
7914 if (filter->range) {
7916 ret = kstrtoul(args[1].from, 0, &filter->size);
7921 if (token == IF_SRC_FILE) {
7922 filename = match_strdup(&args[2]);
7929 state = IF_STATE_END;
7937 * Filter definition is fully parsed, validate and install it.
7938 * Make sure that it doesn't contradict itself or the event's
7941 if (state == IF_STATE_END) {
7942 if (kernel && event->attr.exclude_kernel)
7949 /* look up the path and grab its inode */
7950 ret = kern_path(filename, LOOKUP_FOLLOW, &path);
7952 goto fail_free_name;
7954 filter->inode = igrab(d_inode(path.dentry));
7960 if (!filter->inode ||
7961 !S_ISREG(filter->inode->i_mode))
7962 /* free_filters_list() will iput() */
7966 /* ready to consume more filters */
7967 state = IF_STATE_ACTION;
7972 if (state != IF_STATE_ACTION)
7982 free_filters_list(filters);
7989 perf_event_set_addr_filter(struct perf_event *event, char *filter_str)
7995 * Since this is called in perf_ioctl() path, we're already holding
7998 lockdep_assert_held(&event->ctx->mutex);
8000 if (WARN_ON_ONCE(event->parent))
8004 * For now, we only support filtering in per-task events; doing so
8005 * for CPU-wide events requires additional context switching trickery,
8006 * since same object code will be mapped at different virtual
8007 * addresses in different processes.
8009 if (!event->ctx->task)
8012 ret = perf_event_parse_addr_filter(event, filter_str, &filters);
8016 ret = event->pmu->addr_filters_validate(&filters);
8018 free_filters_list(&filters);
8022 /* remove existing filters, if any */
8023 perf_addr_filters_splice(event, &filters);
8025 /* install new filters */
8026 perf_event_for_each_child(event, perf_event_addr_filters_apply);
8031 static int perf_event_set_filter(struct perf_event *event, void __user *arg)
8036 if ((event->attr.type != PERF_TYPE_TRACEPOINT ||
8037 !IS_ENABLED(CONFIG_EVENT_TRACING)) &&
8038 !has_addr_filter(event))
8041 filter_str = strndup_user(arg, PAGE_SIZE);
8042 if (IS_ERR(filter_str))
8043 return PTR_ERR(filter_str);
8045 if (IS_ENABLED(CONFIG_EVENT_TRACING) &&
8046 event->attr.type == PERF_TYPE_TRACEPOINT)
8047 ret = ftrace_profile_set_filter(event, event->attr.config,
8049 else if (has_addr_filter(event))
8050 ret = perf_event_set_addr_filter(event, filter_str);
8057 * hrtimer based swevent callback
8060 static enum hrtimer_restart perf_swevent_hrtimer(struct hrtimer *hrtimer)
8062 enum hrtimer_restart ret = HRTIMER_RESTART;
8063 struct perf_sample_data data;
8064 struct pt_regs *regs;
8065 struct perf_event *event;
8068 event = container_of(hrtimer, struct perf_event, hw.hrtimer);
8070 if (event->state != PERF_EVENT_STATE_ACTIVE)
8071 return HRTIMER_NORESTART;
8073 event->pmu->read(event);
8075 perf_sample_data_init(&data, 0, event->hw.last_period);
8076 regs = get_irq_regs();
8078 if (regs && !perf_exclude_event(event, regs)) {
8079 if (!(event->attr.exclude_idle && is_idle_task(current)))
8080 if (__perf_event_overflow(event, 1, &data, regs))
8081 ret = HRTIMER_NORESTART;
8084 period = max_t(u64, 10000, event->hw.sample_period);
8085 hrtimer_forward_now(hrtimer, ns_to_ktime(period));
8090 static void perf_swevent_start_hrtimer(struct perf_event *event)
8092 struct hw_perf_event *hwc = &event->hw;
8095 if (!is_sampling_event(event))
8098 period = local64_read(&hwc->period_left);
8103 local64_set(&hwc->period_left, 0);
8105 period = max_t(u64, 10000, hwc->sample_period);
8107 hrtimer_start(&hwc->hrtimer, ns_to_ktime(period),
8108 HRTIMER_MODE_REL_PINNED);
8111 static void perf_swevent_cancel_hrtimer(struct perf_event *event)
8113 struct hw_perf_event *hwc = &event->hw;
8115 if (is_sampling_event(event)) {
8116 ktime_t remaining = hrtimer_get_remaining(&hwc->hrtimer);
8117 local64_set(&hwc->period_left, ktime_to_ns(remaining));
8119 hrtimer_cancel(&hwc->hrtimer);
8123 static void perf_swevent_init_hrtimer(struct perf_event *event)
8125 struct hw_perf_event *hwc = &event->hw;
8127 if (!is_sampling_event(event))
8130 hrtimer_init(&hwc->hrtimer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
8131 hwc->hrtimer.function = perf_swevent_hrtimer;
8134 * Since hrtimers have a fixed rate, we can do a static freq->period
8135 * mapping and avoid the whole period adjust feedback stuff.
8137 if (event->attr.freq) {
8138 long freq = event->attr.sample_freq;
8140 event->attr.sample_period = NSEC_PER_SEC / freq;
8141 hwc->sample_period = event->attr.sample_period;
8142 local64_set(&hwc->period_left, hwc->sample_period);
8143 hwc->last_period = hwc->sample_period;
8144 event->attr.freq = 0;
8149 * Software event: cpu wall time clock
8152 static void cpu_clock_event_update(struct perf_event *event)
8157 now = local_clock();
8158 prev = local64_xchg(&event->hw.prev_count, now);
8159 local64_add(now - prev, &event->count);
8162 static void cpu_clock_event_start(struct perf_event *event, int flags)
8164 local64_set(&event->hw.prev_count, local_clock());
8165 perf_swevent_start_hrtimer(event);
8168 static void cpu_clock_event_stop(struct perf_event *event, int flags)
8170 perf_swevent_cancel_hrtimer(event);
8171 cpu_clock_event_update(event);
8174 static int cpu_clock_event_add(struct perf_event *event, int flags)
8176 if (flags & PERF_EF_START)
8177 cpu_clock_event_start(event, flags);
8178 perf_event_update_userpage(event);
8183 static void cpu_clock_event_del(struct perf_event *event, int flags)
8185 cpu_clock_event_stop(event, flags);
8188 static void cpu_clock_event_read(struct perf_event *event)
8190 cpu_clock_event_update(event);
8193 static int cpu_clock_event_init(struct perf_event *event)
8195 if (event->attr.type != PERF_TYPE_SOFTWARE)
8198 if (event->attr.config != PERF_COUNT_SW_CPU_CLOCK)
8202 * no branch sampling for software events
8204 if (has_branch_stack(event))
8207 perf_swevent_init_hrtimer(event);
8212 static struct pmu perf_cpu_clock = {
8213 .task_ctx_nr = perf_sw_context,
8215 .capabilities = PERF_PMU_CAP_NO_NMI,
8217 .event_init = cpu_clock_event_init,
8218 .add = cpu_clock_event_add,
8219 .del = cpu_clock_event_del,
8220 .start = cpu_clock_event_start,
8221 .stop = cpu_clock_event_stop,
8222 .read = cpu_clock_event_read,
8226 * Software event: task time clock
8229 static void task_clock_event_update(struct perf_event *event, u64 now)
8234 prev = local64_xchg(&event->hw.prev_count, now);
8236 local64_add(delta, &event->count);
8239 static void task_clock_event_start(struct perf_event *event, int flags)
8241 local64_set(&event->hw.prev_count, event->ctx->time);
8242 perf_swevent_start_hrtimer(event);
8245 static void task_clock_event_stop(struct perf_event *event, int flags)
8247 perf_swevent_cancel_hrtimer(event);
8248 task_clock_event_update(event, event->ctx->time);
8251 static int task_clock_event_add(struct perf_event *event, int flags)
8253 if (flags & PERF_EF_START)
8254 task_clock_event_start(event, flags);
8255 perf_event_update_userpage(event);
8260 static void task_clock_event_del(struct perf_event *event, int flags)
8262 task_clock_event_stop(event, PERF_EF_UPDATE);
8265 static void task_clock_event_read(struct perf_event *event)
8267 u64 now = perf_clock();
8268 u64 delta = now - event->ctx->timestamp;
8269 u64 time = event->ctx->time + delta;
8271 task_clock_event_update(event, time);
8274 static int task_clock_event_init(struct perf_event *event)
8276 if (event->attr.type != PERF_TYPE_SOFTWARE)
8279 if (event->attr.config != PERF_COUNT_SW_TASK_CLOCK)
8283 * no branch sampling for software events
8285 if (has_branch_stack(event))
8288 perf_swevent_init_hrtimer(event);
8293 static struct pmu perf_task_clock = {
8294 .task_ctx_nr = perf_sw_context,
8296 .capabilities = PERF_PMU_CAP_NO_NMI,
8298 .event_init = task_clock_event_init,
8299 .add = task_clock_event_add,
8300 .del = task_clock_event_del,
8301 .start = task_clock_event_start,
8302 .stop = task_clock_event_stop,
8303 .read = task_clock_event_read,
8306 static void perf_pmu_nop_void(struct pmu *pmu)
8310 static void perf_pmu_nop_txn(struct pmu *pmu, unsigned int flags)
8314 static int perf_pmu_nop_int(struct pmu *pmu)
8319 static DEFINE_PER_CPU(unsigned int, nop_txn_flags);
8321 static void perf_pmu_start_txn(struct pmu *pmu, unsigned int flags)
8323 __this_cpu_write(nop_txn_flags, flags);
8325 if (flags & ~PERF_PMU_TXN_ADD)
8328 perf_pmu_disable(pmu);
8331 static int perf_pmu_commit_txn(struct pmu *pmu)
8333 unsigned int flags = __this_cpu_read(nop_txn_flags);
8335 __this_cpu_write(nop_txn_flags, 0);
8337 if (flags & ~PERF_PMU_TXN_ADD)
8340 perf_pmu_enable(pmu);
8344 static void perf_pmu_cancel_txn(struct pmu *pmu)
8346 unsigned int flags = __this_cpu_read(nop_txn_flags);
8348 __this_cpu_write(nop_txn_flags, 0);
8350 if (flags & ~PERF_PMU_TXN_ADD)
8353 perf_pmu_enable(pmu);
8356 static int perf_event_idx_default(struct perf_event *event)
8362 * Ensures all contexts with the same task_ctx_nr have the same
8363 * pmu_cpu_context too.
8365 static struct perf_cpu_context __percpu *find_pmu_context(int ctxn)
8372 list_for_each_entry(pmu, &pmus, entry) {
8373 if (pmu->task_ctx_nr == ctxn)
8374 return pmu->pmu_cpu_context;
8380 static void update_pmu_context(struct pmu *pmu, struct pmu *old_pmu)
8384 for_each_possible_cpu(cpu) {
8385 struct perf_cpu_context *cpuctx;
8387 cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
8389 if (cpuctx->unique_pmu == old_pmu)
8390 cpuctx->unique_pmu = pmu;
8394 static void free_pmu_context(struct pmu *pmu)
8398 mutex_lock(&pmus_lock);
8400 * Like a real lame refcount.
8402 list_for_each_entry(i, &pmus, entry) {
8403 if (i->pmu_cpu_context == pmu->pmu_cpu_context) {
8404 update_pmu_context(i, pmu);
8409 free_percpu(pmu->pmu_cpu_context);
8411 mutex_unlock(&pmus_lock);
8415 * Let userspace know that this PMU supports address range filtering:
8417 static ssize_t nr_addr_filters_show(struct device *dev,
8418 struct device_attribute *attr,
8421 struct pmu *pmu = dev_get_drvdata(dev);
8423 return snprintf(page, PAGE_SIZE - 1, "%d\n", pmu->nr_addr_filters);
8425 DEVICE_ATTR_RO(nr_addr_filters);
8427 static struct idr pmu_idr;
8430 type_show(struct device *dev, struct device_attribute *attr, char *page)
8432 struct pmu *pmu = dev_get_drvdata(dev);
8434 return snprintf(page, PAGE_SIZE-1, "%d\n", pmu->type);
8436 static DEVICE_ATTR_RO(type);
8439 perf_event_mux_interval_ms_show(struct device *dev,
8440 struct device_attribute *attr,
8443 struct pmu *pmu = dev_get_drvdata(dev);
8445 return snprintf(page, PAGE_SIZE-1, "%d\n", pmu->hrtimer_interval_ms);
8448 static DEFINE_MUTEX(mux_interval_mutex);
8451 perf_event_mux_interval_ms_store(struct device *dev,
8452 struct device_attribute *attr,
8453 const char *buf, size_t count)
8455 struct pmu *pmu = dev_get_drvdata(dev);
8456 int timer, cpu, ret;
8458 ret = kstrtoint(buf, 0, &timer);
8465 /* same value, noting to do */
8466 if (timer == pmu->hrtimer_interval_ms)
8469 mutex_lock(&mux_interval_mutex);
8470 pmu->hrtimer_interval_ms = timer;
8472 /* update all cpuctx for this PMU */
8474 for_each_online_cpu(cpu) {
8475 struct perf_cpu_context *cpuctx;
8476 cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
8477 cpuctx->hrtimer_interval = ns_to_ktime(NSEC_PER_MSEC * timer);
8479 cpu_function_call(cpu,
8480 (remote_function_f)perf_mux_hrtimer_restart, cpuctx);
8483 mutex_unlock(&mux_interval_mutex);
8487 static DEVICE_ATTR_RW(perf_event_mux_interval_ms);
8489 static struct attribute *pmu_dev_attrs[] = {
8490 &dev_attr_type.attr,
8491 &dev_attr_perf_event_mux_interval_ms.attr,
8494 ATTRIBUTE_GROUPS(pmu_dev);
8496 static int pmu_bus_running;
8497 static struct bus_type pmu_bus = {
8498 .name = "event_source",
8499 .dev_groups = pmu_dev_groups,
8502 static void pmu_dev_release(struct device *dev)
8507 static int pmu_dev_alloc(struct pmu *pmu)
8511 pmu->dev = kzalloc(sizeof(struct device), GFP_KERNEL);
8515 pmu->dev->groups = pmu->attr_groups;
8516 device_initialize(pmu->dev);
8517 ret = dev_set_name(pmu->dev, "%s", pmu->name);
8521 dev_set_drvdata(pmu->dev, pmu);
8522 pmu->dev->bus = &pmu_bus;
8523 pmu->dev->release = pmu_dev_release;
8524 ret = device_add(pmu->dev);
8528 /* For PMUs with address filters, throw in an extra attribute: */
8529 if (pmu->nr_addr_filters)
8530 ret = device_create_file(pmu->dev, &dev_attr_nr_addr_filters);
8539 device_del(pmu->dev);
8542 put_device(pmu->dev);
8546 static struct lock_class_key cpuctx_mutex;
8547 static struct lock_class_key cpuctx_lock;
8549 int perf_pmu_register(struct pmu *pmu, const char *name, int type)
8553 mutex_lock(&pmus_lock);
8555 pmu->pmu_disable_count = alloc_percpu(int);
8556 if (!pmu->pmu_disable_count)
8565 type = idr_alloc(&pmu_idr, pmu, PERF_TYPE_MAX, 0, GFP_KERNEL);
8573 if (pmu_bus_running) {
8574 ret = pmu_dev_alloc(pmu);
8580 if (pmu->task_ctx_nr == perf_hw_context) {
8581 static int hw_context_taken = 0;
8584 * Other than systems with heterogeneous CPUs, it never makes
8585 * sense for two PMUs to share perf_hw_context. PMUs which are
8586 * uncore must use perf_invalid_context.
8588 if (WARN_ON_ONCE(hw_context_taken &&
8589 !(pmu->capabilities & PERF_PMU_CAP_HETEROGENEOUS_CPUS)))
8590 pmu->task_ctx_nr = perf_invalid_context;
8592 hw_context_taken = 1;
8595 pmu->pmu_cpu_context = find_pmu_context(pmu->task_ctx_nr);
8596 if (pmu->pmu_cpu_context)
8597 goto got_cpu_context;
8600 pmu->pmu_cpu_context = alloc_percpu(struct perf_cpu_context);
8601 if (!pmu->pmu_cpu_context)
8604 for_each_possible_cpu(cpu) {
8605 struct perf_cpu_context *cpuctx;
8607 cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
8608 __perf_event_init_context(&cpuctx->ctx);
8609 lockdep_set_class(&cpuctx->ctx.mutex, &cpuctx_mutex);
8610 lockdep_set_class(&cpuctx->ctx.lock, &cpuctx_lock);
8611 cpuctx->ctx.pmu = pmu;
8613 __perf_mux_hrtimer_init(cpuctx, cpu);
8615 cpuctx->unique_pmu = pmu;
8619 if (!pmu->start_txn) {
8620 if (pmu->pmu_enable) {
8622 * If we have pmu_enable/pmu_disable calls, install
8623 * transaction stubs that use that to try and batch
8624 * hardware accesses.
8626 pmu->start_txn = perf_pmu_start_txn;
8627 pmu->commit_txn = perf_pmu_commit_txn;
8628 pmu->cancel_txn = perf_pmu_cancel_txn;
8630 pmu->start_txn = perf_pmu_nop_txn;
8631 pmu->commit_txn = perf_pmu_nop_int;
8632 pmu->cancel_txn = perf_pmu_nop_void;
8636 if (!pmu->pmu_enable) {
8637 pmu->pmu_enable = perf_pmu_nop_void;
8638 pmu->pmu_disable = perf_pmu_nop_void;
8641 if (!pmu->event_idx)
8642 pmu->event_idx = perf_event_idx_default;
8644 list_add_rcu(&pmu->entry, &pmus);
8645 atomic_set(&pmu->exclusive_cnt, 0);
8648 mutex_unlock(&pmus_lock);
8653 device_del(pmu->dev);
8654 put_device(pmu->dev);
8657 if (pmu->type >= PERF_TYPE_MAX)
8658 idr_remove(&pmu_idr, pmu->type);
8661 free_percpu(pmu->pmu_disable_count);
8664 EXPORT_SYMBOL_GPL(perf_pmu_register);
8666 void perf_pmu_unregister(struct pmu *pmu)
8668 mutex_lock(&pmus_lock);
8669 list_del_rcu(&pmu->entry);
8670 mutex_unlock(&pmus_lock);
8673 * We dereference the pmu list under both SRCU and regular RCU, so
8674 * synchronize against both of those.
8676 synchronize_srcu(&pmus_srcu);
8679 free_percpu(pmu->pmu_disable_count);
8680 if (pmu->type >= PERF_TYPE_MAX)
8681 idr_remove(&pmu_idr, pmu->type);
8682 if (pmu->nr_addr_filters)
8683 device_remove_file(pmu->dev, &dev_attr_nr_addr_filters);
8684 device_del(pmu->dev);
8685 put_device(pmu->dev);
8686 free_pmu_context(pmu);
8688 EXPORT_SYMBOL_GPL(perf_pmu_unregister);
8690 static int perf_try_init_event(struct pmu *pmu, struct perf_event *event)
8692 struct perf_event_context *ctx = NULL;
8695 if (!try_module_get(pmu->module))
8698 if (event->group_leader != event) {
8700 * This ctx->mutex can nest when we're called through
8701 * inheritance. See the perf_event_ctx_lock_nested() comment.
8703 ctx = perf_event_ctx_lock_nested(event->group_leader,
8704 SINGLE_DEPTH_NESTING);
8709 ret = pmu->event_init(event);
8712 perf_event_ctx_unlock(event->group_leader, ctx);
8715 module_put(pmu->module);
8720 static struct pmu *perf_init_event(struct perf_event *event)
8722 struct pmu *pmu = NULL;
8726 idx = srcu_read_lock(&pmus_srcu);
8729 pmu = idr_find(&pmu_idr, event->attr.type);
8732 ret = perf_try_init_event(pmu, event);
8738 list_for_each_entry_rcu(pmu, &pmus, entry) {
8739 ret = perf_try_init_event(pmu, event);
8743 if (ret != -ENOENT) {
8748 pmu = ERR_PTR(-ENOENT);
8750 srcu_read_unlock(&pmus_srcu, idx);
8755 static void attach_sb_event(struct perf_event *event)
8757 struct pmu_event_list *pel = per_cpu_ptr(&pmu_sb_events, event->cpu);
8759 raw_spin_lock(&pel->lock);
8760 list_add_rcu(&event->sb_list, &pel->list);
8761 raw_spin_unlock(&pel->lock);
8765 * We keep a list of all !task (and therefore per-cpu) events
8766 * that need to receive side-band records.
8768 * This avoids having to scan all the various PMU per-cpu contexts
8771 static void account_pmu_sb_event(struct perf_event *event)
8773 if (is_sb_event(event))
8774 attach_sb_event(event);
8777 static void account_event_cpu(struct perf_event *event, int cpu)
8782 if (is_cgroup_event(event))
8783 atomic_inc(&per_cpu(perf_cgroup_events, cpu));
8786 /* Freq events need the tick to stay alive (see perf_event_task_tick). */
8787 static void account_freq_event_nohz(void)
8789 #ifdef CONFIG_NO_HZ_FULL
8790 /* Lock so we don't race with concurrent unaccount */
8791 spin_lock(&nr_freq_lock);
8792 if (atomic_inc_return(&nr_freq_events) == 1)
8793 tick_nohz_dep_set(TICK_DEP_BIT_PERF_EVENTS);
8794 spin_unlock(&nr_freq_lock);
8798 static void account_freq_event(void)
8800 if (tick_nohz_full_enabled())
8801 account_freq_event_nohz();
8803 atomic_inc(&nr_freq_events);
8807 static void account_event(struct perf_event *event)
8814 if (event->attach_state & PERF_ATTACH_TASK)
8816 if (event->attr.mmap || event->attr.mmap_data)
8817 atomic_inc(&nr_mmap_events);
8818 if (event->attr.comm)
8819 atomic_inc(&nr_comm_events);
8820 if (event->attr.task)
8821 atomic_inc(&nr_task_events);
8822 if (event->attr.freq)
8823 account_freq_event();
8824 if (event->attr.context_switch) {
8825 atomic_inc(&nr_switch_events);
8828 if (has_branch_stack(event))
8830 if (is_cgroup_event(event))
8834 if (atomic_inc_not_zero(&perf_sched_count))
8837 mutex_lock(&perf_sched_mutex);
8838 if (!atomic_read(&perf_sched_count)) {
8839 static_branch_enable(&perf_sched_events);
8841 * Guarantee that all CPUs observe they key change and
8842 * call the perf scheduling hooks before proceeding to
8843 * install events that need them.
8845 synchronize_sched();
8848 * Now that we have waited for the sync_sched(), allow further
8849 * increments to by-pass the mutex.
8851 atomic_inc(&perf_sched_count);
8852 mutex_unlock(&perf_sched_mutex);
8856 account_event_cpu(event, event->cpu);
8858 account_pmu_sb_event(event);
8862 * Allocate and initialize a event structure
8864 static struct perf_event *
8865 perf_event_alloc(struct perf_event_attr *attr, int cpu,
8866 struct task_struct *task,
8867 struct perf_event *group_leader,
8868 struct perf_event *parent_event,
8869 perf_overflow_handler_t overflow_handler,
8870 void *context, int cgroup_fd)
8873 struct perf_event *event;
8874 struct hw_perf_event *hwc;
8877 if ((unsigned)cpu >= nr_cpu_ids) {
8878 if (!task || cpu != -1)
8879 return ERR_PTR(-EINVAL);
8882 event = kzalloc(sizeof(*event), GFP_KERNEL);
8884 return ERR_PTR(-ENOMEM);
8887 * Single events are their own group leaders, with an
8888 * empty sibling list:
8891 group_leader = event;
8893 mutex_init(&event->child_mutex);
8894 INIT_LIST_HEAD(&event->child_list);
8896 INIT_LIST_HEAD(&event->group_entry);
8897 INIT_LIST_HEAD(&event->event_entry);
8898 INIT_LIST_HEAD(&event->sibling_list);
8899 INIT_LIST_HEAD(&event->rb_entry);
8900 INIT_LIST_HEAD(&event->active_entry);
8901 INIT_LIST_HEAD(&event->addr_filters.list);
8902 INIT_HLIST_NODE(&event->hlist_entry);
8905 init_waitqueue_head(&event->waitq);
8906 init_irq_work(&event->pending, perf_pending_event);
8908 mutex_init(&event->mmap_mutex);
8909 raw_spin_lock_init(&event->addr_filters.lock);
8911 atomic_long_set(&event->refcount, 1);
8913 event->attr = *attr;
8914 event->group_leader = group_leader;
8918 event->parent = parent_event;
8920 event->ns = get_pid_ns(task_active_pid_ns(current));
8921 event->id = atomic64_inc_return(&perf_event_id);
8923 event->state = PERF_EVENT_STATE_INACTIVE;
8926 event->attach_state = PERF_ATTACH_TASK;
8928 * XXX pmu::event_init needs to know what task to account to
8929 * and we cannot use the ctx information because we need the
8930 * pmu before we get a ctx.
8932 event->hw.target = task;
8935 event->clock = &local_clock;
8937 event->clock = parent_event->clock;
8939 if (!overflow_handler && parent_event) {
8940 overflow_handler = parent_event->overflow_handler;
8941 context = parent_event->overflow_handler_context;
8944 if (overflow_handler) {
8945 event->overflow_handler = overflow_handler;
8946 event->overflow_handler_context = context;
8947 } else if (is_write_backward(event)){
8948 event->overflow_handler = perf_event_output_backward;
8949 event->overflow_handler_context = NULL;
8951 event->overflow_handler = perf_event_output_forward;
8952 event->overflow_handler_context = NULL;
8955 perf_event__state_init(event);
8960 hwc->sample_period = attr->sample_period;
8961 if (attr->freq && attr->sample_freq)
8962 hwc->sample_period = 1;
8963 hwc->last_period = hwc->sample_period;
8965 local64_set(&hwc->period_left, hwc->sample_period);
8968 * we currently do not support PERF_FORMAT_GROUP on inherited events
8970 if (attr->inherit && (attr->read_format & PERF_FORMAT_GROUP))
8973 if (!has_branch_stack(event))
8974 event->attr.branch_sample_type = 0;
8976 if (cgroup_fd != -1) {
8977 err = perf_cgroup_connect(cgroup_fd, event, attr, group_leader);
8982 pmu = perf_init_event(event);
8985 else if (IS_ERR(pmu)) {
8990 err = exclusive_event_init(event);
8994 if (has_addr_filter(event)) {
8995 event->addr_filters_offs = kcalloc(pmu->nr_addr_filters,
8996 sizeof(unsigned long),
8998 if (!event->addr_filters_offs)
9001 /* force hw sync on the address filters */
9002 event->addr_filters_gen = 1;
9005 if (!event->parent) {
9006 if (event->attr.sample_type & PERF_SAMPLE_CALLCHAIN) {
9007 err = get_callchain_buffers(attr->sample_max_stack);
9009 goto err_addr_filters;
9013 /* symmetric to unaccount_event() in _free_event() */
9014 account_event(event);
9019 kfree(event->addr_filters_offs);
9022 exclusive_event_destroy(event);
9026 event->destroy(event);
9027 module_put(pmu->module);
9029 if (is_cgroup_event(event))
9030 perf_detach_cgroup(event);
9032 put_pid_ns(event->ns);
9035 return ERR_PTR(err);
9038 static int perf_copy_attr(struct perf_event_attr __user *uattr,
9039 struct perf_event_attr *attr)
9044 if (!access_ok(VERIFY_WRITE, uattr, PERF_ATTR_SIZE_VER0))
9048 * zero the full structure, so that a short copy will be nice.
9050 memset(attr, 0, sizeof(*attr));
9052 ret = get_user(size, &uattr->size);
9056 if (size > PAGE_SIZE) /* silly large */
9059 if (!size) /* abi compat */
9060 size = PERF_ATTR_SIZE_VER0;
9062 if (size < PERF_ATTR_SIZE_VER0)
9066 * If we're handed a bigger struct than we know of,
9067 * ensure all the unknown bits are 0 - i.e. new
9068 * user-space does not rely on any kernel feature
9069 * extensions we dont know about yet.
9071 if (size > sizeof(*attr)) {
9072 unsigned char __user *addr;
9073 unsigned char __user *end;
9076 addr = (void __user *)uattr + sizeof(*attr);
9077 end = (void __user *)uattr + size;
9079 for (; addr < end; addr++) {
9080 ret = get_user(val, addr);
9086 size = sizeof(*attr);
9089 ret = copy_from_user(attr, uattr, size);
9093 if (attr->__reserved_1)
9096 if (attr->sample_type & ~(PERF_SAMPLE_MAX-1))
9099 if (attr->read_format & ~(PERF_FORMAT_MAX-1))
9102 if (attr->sample_type & PERF_SAMPLE_BRANCH_STACK) {
9103 u64 mask = attr->branch_sample_type;
9105 /* only using defined bits */
9106 if (mask & ~(PERF_SAMPLE_BRANCH_MAX-1))
9109 /* at least one branch bit must be set */
9110 if (!(mask & ~PERF_SAMPLE_BRANCH_PLM_ALL))
9113 /* propagate priv level, when not set for branch */
9114 if (!(mask & PERF_SAMPLE_BRANCH_PLM_ALL)) {
9116 /* exclude_kernel checked on syscall entry */
9117 if (!attr->exclude_kernel)
9118 mask |= PERF_SAMPLE_BRANCH_KERNEL;
9120 if (!attr->exclude_user)
9121 mask |= PERF_SAMPLE_BRANCH_USER;
9123 if (!attr->exclude_hv)
9124 mask |= PERF_SAMPLE_BRANCH_HV;
9126 * adjust user setting (for HW filter setup)
9128 attr->branch_sample_type = mask;
9130 /* privileged levels capture (kernel, hv): check permissions */
9131 if ((mask & PERF_SAMPLE_BRANCH_PERM_PLM)
9132 && perf_paranoid_kernel() && !capable(CAP_SYS_ADMIN))
9136 if (attr->sample_type & PERF_SAMPLE_REGS_USER) {
9137 ret = perf_reg_validate(attr->sample_regs_user);
9142 if (attr->sample_type & PERF_SAMPLE_STACK_USER) {
9143 if (!arch_perf_have_user_stack_dump())
9147 * We have __u32 type for the size, but so far
9148 * we can only use __u16 as maximum due to the
9149 * __u16 sample size limit.
9151 if (attr->sample_stack_user >= USHRT_MAX)
9153 else if (!IS_ALIGNED(attr->sample_stack_user, sizeof(u64)))
9157 if (attr->sample_type & PERF_SAMPLE_REGS_INTR)
9158 ret = perf_reg_validate(attr->sample_regs_intr);
9163 put_user(sizeof(*attr), &uattr->size);
9169 perf_event_set_output(struct perf_event *event, struct perf_event *output_event)
9171 struct ring_buffer *rb = NULL;
9177 /* don't allow circular references */
9178 if (event == output_event)
9182 * Don't allow cross-cpu buffers
9184 if (output_event->cpu != event->cpu)
9188 * If its not a per-cpu rb, it must be the same task.
9190 if (output_event->cpu == -1 && output_event->ctx != event->ctx)
9194 * Mixing clocks in the same buffer is trouble you don't need.
9196 if (output_event->clock != event->clock)
9200 * Either writing ring buffer from beginning or from end.
9201 * Mixing is not allowed.
9203 if (is_write_backward(output_event) != is_write_backward(event))
9207 * If both events generate aux data, they must be on the same PMU
9209 if (has_aux(event) && has_aux(output_event) &&
9210 event->pmu != output_event->pmu)
9214 mutex_lock(&event->mmap_mutex);
9215 /* Can't redirect output if we've got an active mmap() */
9216 if (atomic_read(&event->mmap_count))
9220 /* get the rb we want to redirect to */
9221 rb = ring_buffer_get(output_event);
9226 ring_buffer_attach(event, rb);
9230 mutex_unlock(&event->mmap_mutex);
9236 static void mutex_lock_double(struct mutex *a, struct mutex *b)
9242 mutex_lock_nested(b, SINGLE_DEPTH_NESTING);
9245 static int perf_event_set_clock(struct perf_event *event, clockid_t clk_id)
9247 bool nmi_safe = false;
9250 case CLOCK_MONOTONIC:
9251 event->clock = &ktime_get_mono_fast_ns;
9255 case CLOCK_MONOTONIC_RAW:
9256 event->clock = &ktime_get_raw_fast_ns;
9260 case CLOCK_REALTIME:
9261 event->clock = &ktime_get_real_ns;
9264 case CLOCK_BOOTTIME:
9265 event->clock = &ktime_get_boot_ns;
9269 event->clock = &ktime_get_tai_ns;
9276 if (!nmi_safe && !(event->pmu->capabilities & PERF_PMU_CAP_NO_NMI))
9283 * sys_perf_event_open - open a performance event, associate it to a task/cpu
9285 * @attr_uptr: event_id type attributes for monitoring/sampling
9288 * @group_fd: group leader event fd
9290 SYSCALL_DEFINE5(perf_event_open,
9291 struct perf_event_attr __user *, attr_uptr,
9292 pid_t, pid, int, cpu, int, group_fd, unsigned long, flags)
9294 struct perf_event *group_leader = NULL, *output_event = NULL;
9295 struct perf_event *event, *sibling;
9296 struct perf_event_attr attr;
9297 struct perf_event_context *ctx, *uninitialized_var(gctx);
9298 struct file *event_file = NULL;
9299 struct fd group = {NULL, 0};
9300 struct task_struct *task = NULL;
9305 int f_flags = O_RDWR;
9308 /* for future expandability... */
9309 if (flags & ~PERF_FLAG_ALL)
9312 err = perf_copy_attr(attr_uptr, &attr);
9316 if (!attr.exclude_kernel) {
9317 if (perf_paranoid_kernel() && !capable(CAP_SYS_ADMIN))
9322 if (attr.sample_freq > sysctl_perf_event_sample_rate)
9325 if (attr.sample_period & (1ULL << 63))
9329 if (!attr.sample_max_stack)
9330 attr.sample_max_stack = sysctl_perf_event_max_stack;
9333 * In cgroup mode, the pid argument is used to pass the fd
9334 * opened to the cgroup directory in cgroupfs. The cpu argument
9335 * designates the cpu on which to monitor threads from that
9338 if ((flags & PERF_FLAG_PID_CGROUP) && (pid == -1 || cpu == -1))
9341 if (flags & PERF_FLAG_FD_CLOEXEC)
9342 f_flags |= O_CLOEXEC;
9344 event_fd = get_unused_fd_flags(f_flags);
9348 if (group_fd != -1) {
9349 err = perf_fget_light(group_fd, &group);
9352 group_leader = group.file->private_data;
9353 if (flags & PERF_FLAG_FD_OUTPUT)
9354 output_event = group_leader;
9355 if (flags & PERF_FLAG_FD_NO_GROUP)
9356 group_leader = NULL;
9359 if (pid != -1 && !(flags & PERF_FLAG_PID_CGROUP)) {
9360 task = find_lively_task_by_vpid(pid);
9362 err = PTR_ERR(task);
9367 if (task && group_leader &&
9368 group_leader->attr.inherit != attr.inherit) {
9376 err = mutex_lock_interruptible(&task->signal->cred_guard_mutex);
9381 * Reuse ptrace permission checks for now.
9383 * We must hold cred_guard_mutex across this and any potential
9384 * perf_install_in_context() call for this new event to
9385 * serialize against exec() altering our credentials (and the
9386 * perf_event_exit_task() that could imply).
9389 if (!ptrace_may_access(task, PTRACE_MODE_READ_REALCREDS))
9393 if (flags & PERF_FLAG_PID_CGROUP)
9396 event = perf_event_alloc(&attr, cpu, task, group_leader, NULL,
9397 NULL, NULL, cgroup_fd);
9398 if (IS_ERR(event)) {
9399 err = PTR_ERR(event);
9403 if (is_sampling_event(event)) {
9404 if (event->pmu->capabilities & PERF_PMU_CAP_NO_INTERRUPT) {
9411 * Special case software events and allow them to be part of
9412 * any hardware group.
9416 if (attr.use_clockid) {
9417 err = perf_event_set_clock(event, attr.clockid);
9423 (is_software_event(event) != is_software_event(group_leader))) {
9424 if (is_software_event(event)) {
9426 * If event and group_leader are not both a software
9427 * event, and event is, then group leader is not.
9429 * Allow the addition of software events to !software
9430 * groups, this is safe because software events never
9433 pmu = group_leader->pmu;
9434 } else if (is_software_event(group_leader) &&
9435 (group_leader->group_flags & PERF_GROUP_SOFTWARE)) {
9437 * In case the group is a pure software group, and we
9438 * try to add a hardware event, move the whole group to
9439 * the hardware context.
9446 * Get the target context (task or percpu):
9448 ctx = find_get_context(pmu, task, event);
9454 if ((pmu->capabilities & PERF_PMU_CAP_EXCLUSIVE) && group_leader) {
9460 * Look up the group leader (we will attach this event to it):
9466 * Do not allow a recursive hierarchy (this new sibling
9467 * becoming part of another group-sibling):
9469 if (group_leader->group_leader != group_leader)
9472 /* All events in a group should have the same clock */
9473 if (group_leader->clock != event->clock)
9477 * Do not allow to attach to a group in a different
9478 * task or CPU context:
9482 * Make sure we're both on the same task, or both
9485 if (group_leader->ctx->task != ctx->task)
9489 * Make sure we're both events for the same CPU;
9490 * grouping events for different CPUs is broken; since
9491 * you can never concurrently schedule them anyhow.
9493 if (group_leader->cpu != event->cpu)
9496 if (group_leader->ctx != ctx)
9501 * Only a group leader can be exclusive or pinned
9503 if (attr.exclusive || attr.pinned)
9508 err = perf_event_set_output(event, output_event);
9513 event_file = anon_inode_getfile("[perf_event]", &perf_fops, event,
9515 if (IS_ERR(event_file)) {
9516 err = PTR_ERR(event_file);
9522 gctx = group_leader->ctx;
9523 mutex_lock_double(&gctx->mutex, &ctx->mutex);
9524 if (gctx->task == TASK_TOMBSTONE) {
9529 mutex_lock(&ctx->mutex);
9532 if (ctx->task == TASK_TOMBSTONE) {
9537 if (!perf_event_validate_size(event)) {
9543 * Must be under the same ctx::mutex as perf_install_in_context(),
9544 * because we need to serialize with concurrent event creation.
9546 if (!exclusive_event_installable(event, ctx)) {
9547 /* exclusive and group stuff are assumed mutually exclusive */
9548 WARN_ON_ONCE(move_group);
9554 WARN_ON_ONCE(ctx->parent_ctx);
9557 * This is the point on no return; we cannot fail hereafter. This is
9558 * where we start modifying current state.
9563 * See perf_event_ctx_lock() for comments on the details
9564 * of swizzling perf_event::ctx.
9566 perf_remove_from_context(group_leader, 0);
9568 list_for_each_entry(sibling, &group_leader->sibling_list,
9570 perf_remove_from_context(sibling, 0);
9575 * Wait for everybody to stop referencing the events through
9576 * the old lists, before installing it on new lists.
9581 * Install the group siblings before the group leader.
9583 * Because a group leader will try and install the entire group
9584 * (through the sibling list, which is still in-tact), we can
9585 * end up with siblings installed in the wrong context.
9587 * By installing siblings first we NO-OP because they're not
9588 * reachable through the group lists.
9590 list_for_each_entry(sibling, &group_leader->sibling_list,
9592 perf_event__state_init(sibling);
9593 perf_install_in_context(ctx, sibling, sibling->cpu);
9598 * Removing from the context ends up with disabled
9599 * event. What we want here is event in the initial
9600 * startup state, ready to be add into new context.
9602 perf_event__state_init(group_leader);
9603 perf_install_in_context(ctx, group_leader, group_leader->cpu);
9607 * Now that all events are installed in @ctx, nothing
9608 * references @gctx anymore, so drop the last reference we have
9615 * Precalculate sample_data sizes; do while holding ctx::mutex such
9616 * that we're serialized against further additions and before
9617 * perf_install_in_context() which is the point the event is active and
9618 * can use these values.
9620 perf_event__header_size(event);
9621 perf_event__id_header_size(event);
9623 event->owner = current;
9625 perf_install_in_context(ctx, event, event->cpu);
9626 perf_unpin_context(ctx);
9629 mutex_unlock(&gctx->mutex);
9630 mutex_unlock(&ctx->mutex);
9633 mutex_unlock(&task->signal->cred_guard_mutex);
9634 put_task_struct(task);
9639 mutex_lock(¤t->perf_event_mutex);
9640 list_add_tail(&event->owner_entry, ¤t->perf_event_list);
9641 mutex_unlock(¤t->perf_event_mutex);
9644 * Drop the reference on the group_event after placing the
9645 * new event on the sibling_list. This ensures destruction
9646 * of the group leader will find the pointer to itself in
9647 * perf_group_detach().
9650 fd_install(event_fd, event_file);
9655 mutex_unlock(&gctx->mutex);
9656 mutex_unlock(&ctx->mutex);
9660 perf_unpin_context(ctx);
9664 * If event_file is set, the fput() above will have called ->release()
9665 * and that will take care of freeing the event.
9671 mutex_unlock(&task->signal->cred_guard_mutex);
9676 put_task_struct(task);
9680 put_unused_fd(event_fd);
9685 * perf_event_create_kernel_counter
9687 * @attr: attributes of the counter to create
9688 * @cpu: cpu in which the counter is bound
9689 * @task: task to profile (NULL for percpu)
9692 perf_event_create_kernel_counter(struct perf_event_attr *attr, int cpu,
9693 struct task_struct *task,
9694 perf_overflow_handler_t overflow_handler,
9697 struct perf_event_context *ctx;
9698 struct perf_event *event;
9702 * Get the target context (task or percpu):
9705 event = perf_event_alloc(attr, cpu, task, NULL, NULL,
9706 overflow_handler, context, -1);
9707 if (IS_ERR(event)) {
9708 err = PTR_ERR(event);
9712 /* Mark owner so we could distinguish it from user events. */
9713 event->owner = TASK_TOMBSTONE;
9715 ctx = find_get_context(event->pmu, task, event);
9721 WARN_ON_ONCE(ctx->parent_ctx);
9722 mutex_lock(&ctx->mutex);
9723 if (ctx->task == TASK_TOMBSTONE) {
9728 if (!exclusive_event_installable(event, ctx)) {
9733 perf_install_in_context(ctx, event, cpu);
9734 perf_unpin_context(ctx);
9735 mutex_unlock(&ctx->mutex);
9740 mutex_unlock(&ctx->mutex);
9741 perf_unpin_context(ctx);
9746 return ERR_PTR(err);
9748 EXPORT_SYMBOL_GPL(perf_event_create_kernel_counter);
9750 void perf_pmu_migrate_context(struct pmu *pmu, int src_cpu, int dst_cpu)
9752 struct perf_event_context *src_ctx;
9753 struct perf_event_context *dst_ctx;
9754 struct perf_event *event, *tmp;
9757 src_ctx = &per_cpu_ptr(pmu->pmu_cpu_context, src_cpu)->ctx;
9758 dst_ctx = &per_cpu_ptr(pmu->pmu_cpu_context, dst_cpu)->ctx;
9761 * See perf_event_ctx_lock() for comments on the details
9762 * of swizzling perf_event::ctx.
9764 mutex_lock_double(&src_ctx->mutex, &dst_ctx->mutex);
9765 list_for_each_entry_safe(event, tmp, &src_ctx->event_list,
9767 perf_remove_from_context(event, 0);
9768 unaccount_event_cpu(event, src_cpu);
9770 list_add(&event->migrate_entry, &events);
9774 * Wait for the events to quiesce before re-instating them.
9779 * Re-instate events in 2 passes.
9781 * Skip over group leaders and only install siblings on this first
9782 * pass, siblings will not get enabled without a leader, however a
9783 * leader will enable its siblings, even if those are still on the old
9786 list_for_each_entry_safe(event, tmp, &events, migrate_entry) {
9787 if (event->group_leader == event)
9790 list_del(&event->migrate_entry);
9791 if (event->state >= PERF_EVENT_STATE_OFF)
9792 event->state = PERF_EVENT_STATE_INACTIVE;
9793 account_event_cpu(event, dst_cpu);
9794 perf_install_in_context(dst_ctx, event, dst_cpu);
9799 * Once all the siblings are setup properly, install the group leaders
9802 list_for_each_entry_safe(event, tmp, &events, migrate_entry) {
9803 list_del(&event->migrate_entry);
9804 if (event->state >= PERF_EVENT_STATE_OFF)
9805 event->state = PERF_EVENT_STATE_INACTIVE;
9806 account_event_cpu(event, dst_cpu);
9807 perf_install_in_context(dst_ctx, event, dst_cpu);
9810 mutex_unlock(&dst_ctx->mutex);
9811 mutex_unlock(&src_ctx->mutex);
9813 EXPORT_SYMBOL_GPL(perf_pmu_migrate_context);
9815 static void sync_child_event(struct perf_event *child_event,
9816 struct task_struct *child)
9818 struct perf_event *parent_event = child_event->parent;
9821 if (child_event->attr.inherit_stat)
9822 perf_event_read_event(child_event, child);
9824 child_val = perf_event_count(child_event);
9827 * Add back the child's count to the parent's count:
9829 atomic64_add(child_val, &parent_event->child_count);
9830 atomic64_add(child_event->total_time_enabled,
9831 &parent_event->child_total_time_enabled);
9832 atomic64_add(child_event->total_time_running,
9833 &parent_event->child_total_time_running);
9837 perf_event_exit_event(struct perf_event *child_event,
9838 struct perf_event_context *child_ctx,
9839 struct task_struct *child)
9841 struct perf_event *parent_event = child_event->parent;
9844 * Do not destroy the 'original' grouping; because of the context
9845 * switch optimization the original events could've ended up in a
9846 * random child task.
9848 * If we were to destroy the original group, all group related
9849 * operations would cease to function properly after this random
9852 * Do destroy all inherited groups, we don't care about those
9853 * and being thorough is better.
9855 raw_spin_lock_irq(&child_ctx->lock);
9856 WARN_ON_ONCE(child_ctx->is_active);
9859 perf_group_detach(child_event);
9860 list_del_event(child_event, child_ctx);
9861 child_event->state = PERF_EVENT_STATE_EXIT; /* is_event_hup() */
9862 raw_spin_unlock_irq(&child_ctx->lock);
9865 * Parent events are governed by their filedesc, retain them.
9867 if (!parent_event) {
9868 perf_event_wakeup(child_event);
9872 * Child events can be cleaned up.
9875 sync_child_event(child_event, child);
9878 * Remove this event from the parent's list
9880 WARN_ON_ONCE(parent_event->ctx->parent_ctx);
9881 mutex_lock(&parent_event->child_mutex);
9882 list_del_init(&child_event->child_list);
9883 mutex_unlock(&parent_event->child_mutex);
9886 * Kick perf_poll() for is_event_hup().
9888 perf_event_wakeup(parent_event);
9889 free_event(child_event);
9890 put_event(parent_event);
9893 static void perf_event_exit_task_context(struct task_struct *child, int ctxn)
9895 struct perf_event_context *child_ctx, *clone_ctx = NULL;
9896 struct perf_event *child_event, *next;
9898 WARN_ON_ONCE(child != current);
9900 child_ctx = perf_pin_task_context(child, ctxn);
9905 * In order to reduce the amount of tricky in ctx tear-down, we hold
9906 * ctx::mutex over the entire thing. This serializes against almost
9907 * everything that wants to access the ctx.
9909 * The exception is sys_perf_event_open() /
9910 * perf_event_create_kernel_count() which does find_get_context()
9911 * without ctx::mutex (it cannot because of the move_group double mutex
9912 * lock thing). See the comments in perf_install_in_context().
9914 mutex_lock(&child_ctx->mutex);
9917 * In a single ctx::lock section, de-schedule the events and detach the
9918 * context from the task such that we cannot ever get it scheduled back
9921 raw_spin_lock_irq(&child_ctx->lock);
9922 task_ctx_sched_out(__get_cpu_context(child_ctx), child_ctx);
9925 * Now that the context is inactive, destroy the task <-> ctx relation
9926 * and mark the context dead.
9928 RCU_INIT_POINTER(child->perf_event_ctxp[ctxn], NULL);
9929 put_ctx(child_ctx); /* cannot be last */
9930 WRITE_ONCE(child_ctx->task, TASK_TOMBSTONE);
9931 put_task_struct(current); /* cannot be last */
9933 clone_ctx = unclone_ctx(child_ctx);
9934 raw_spin_unlock_irq(&child_ctx->lock);
9940 * Report the task dead after unscheduling the events so that we
9941 * won't get any samples after PERF_RECORD_EXIT. We can however still
9942 * get a few PERF_RECORD_READ events.
9944 perf_event_task(child, child_ctx, 0);
9946 list_for_each_entry_safe(child_event, next, &child_ctx->event_list, event_entry)
9947 perf_event_exit_event(child_event, child_ctx, child);
9949 mutex_unlock(&child_ctx->mutex);
9955 * When a child task exits, feed back event values to parent events.
9957 * Can be called with cred_guard_mutex held when called from
9958 * install_exec_creds().
9960 void perf_event_exit_task(struct task_struct *child)
9962 struct perf_event *event, *tmp;
9965 mutex_lock(&child->perf_event_mutex);
9966 list_for_each_entry_safe(event, tmp, &child->perf_event_list,
9968 list_del_init(&event->owner_entry);
9971 * Ensure the list deletion is visible before we clear
9972 * the owner, closes a race against perf_release() where
9973 * we need to serialize on the owner->perf_event_mutex.
9975 smp_store_release(&event->owner, NULL);
9977 mutex_unlock(&child->perf_event_mutex);
9979 for_each_task_context_nr(ctxn)
9980 perf_event_exit_task_context(child, ctxn);
9983 * The perf_event_exit_task_context calls perf_event_task
9984 * with child's task_ctx, which generates EXIT events for
9985 * child contexts and sets child->perf_event_ctxp[] to NULL.
9986 * At this point we need to send EXIT events to cpu contexts.
9988 perf_event_task(child, NULL, 0);
9991 static void perf_free_event(struct perf_event *event,
9992 struct perf_event_context *ctx)
9994 struct perf_event *parent = event->parent;
9996 if (WARN_ON_ONCE(!parent))
9999 mutex_lock(&parent->child_mutex);
10000 list_del_init(&event->child_list);
10001 mutex_unlock(&parent->child_mutex);
10005 raw_spin_lock_irq(&ctx->lock);
10006 perf_group_detach(event);
10007 list_del_event(event, ctx);
10008 raw_spin_unlock_irq(&ctx->lock);
10013 * Free an unexposed, unused context as created by inheritance by
10014 * perf_event_init_task below, used by fork() in case of fail.
10016 * Not all locks are strictly required, but take them anyway to be nice and
10017 * help out with the lockdep assertions.
10019 void perf_event_free_task(struct task_struct *task)
10021 struct perf_event_context *ctx;
10022 struct perf_event *event, *tmp;
10025 for_each_task_context_nr(ctxn) {
10026 ctx = task->perf_event_ctxp[ctxn];
10030 mutex_lock(&ctx->mutex);
10032 list_for_each_entry_safe(event, tmp, &ctx->pinned_groups,
10034 perf_free_event(event, ctx);
10036 list_for_each_entry_safe(event, tmp, &ctx->flexible_groups,
10038 perf_free_event(event, ctx);
10040 if (!list_empty(&ctx->pinned_groups) ||
10041 !list_empty(&ctx->flexible_groups))
10044 mutex_unlock(&ctx->mutex);
10050 void perf_event_delayed_put(struct task_struct *task)
10054 for_each_task_context_nr(ctxn)
10055 WARN_ON_ONCE(task->perf_event_ctxp[ctxn]);
10058 struct file *perf_event_get(unsigned int fd)
10062 file = fget_raw(fd);
10064 return ERR_PTR(-EBADF);
10066 if (file->f_op != &perf_fops) {
10068 return ERR_PTR(-EBADF);
10074 const struct perf_event_attr *perf_event_attrs(struct perf_event *event)
10077 return ERR_PTR(-EINVAL);
10079 return &event->attr;
10083 * inherit a event from parent task to child task:
10085 static struct perf_event *
10086 inherit_event(struct perf_event *parent_event,
10087 struct task_struct *parent,
10088 struct perf_event_context *parent_ctx,
10089 struct task_struct *child,
10090 struct perf_event *group_leader,
10091 struct perf_event_context *child_ctx)
10093 enum perf_event_active_state parent_state = parent_event->state;
10094 struct perf_event *child_event;
10095 unsigned long flags;
10098 * Instead of creating recursive hierarchies of events,
10099 * we link inherited events back to the original parent,
10100 * which has a filp for sure, which we use as the reference
10103 if (parent_event->parent)
10104 parent_event = parent_event->parent;
10106 child_event = perf_event_alloc(&parent_event->attr,
10109 group_leader, parent_event,
10111 if (IS_ERR(child_event))
10112 return child_event;
10115 * is_orphaned_event() and list_add_tail(&parent_event->child_list)
10116 * must be under the same lock in order to serialize against
10117 * perf_event_release_kernel(), such that either we must observe
10118 * is_orphaned_event() or they will observe us on the child_list.
10120 mutex_lock(&parent_event->child_mutex);
10121 if (is_orphaned_event(parent_event) ||
10122 !atomic_long_inc_not_zero(&parent_event->refcount)) {
10123 mutex_unlock(&parent_event->child_mutex);
10124 free_event(child_event);
10128 get_ctx(child_ctx);
10131 * Make the child state follow the state of the parent event,
10132 * not its attr.disabled bit. We hold the parent's mutex,
10133 * so we won't race with perf_event_{en, dis}able_family.
10135 if (parent_state >= PERF_EVENT_STATE_INACTIVE)
10136 child_event->state = PERF_EVENT_STATE_INACTIVE;
10138 child_event->state = PERF_EVENT_STATE_OFF;
10140 if (parent_event->attr.freq) {
10141 u64 sample_period = parent_event->hw.sample_period;
10142 struct hw_perf_event *hwc = &child_event->hw;
10144 hwc->sample_period = sample_period;
10145 hwc->last_period = sample_period;
10147 local64_set(&hwc->period_left, sample_period);
10150 child_event->ctx = child_ctx;
10151 child_event->overflow_handler = parent_event->overflow_handler;
10152 child_event->overflow_handler_context
10153 = parent_event->overflow_handler_context;
10156 * Precalculate sample_data sizes
10158 perf_event__header_size(child_event);
10159 perf_event__id_header_size(child_event);
10162 * Link it up in the child's context:
10164 raw_spin_lock_irqsave(&child_ctx->lock, flags);
10165 add_event_to_ctx(child_event, child_ctx);
10166 raw_spin_unlock_irqrestore(&child_ctx->lock, flags);
10169 * Link this into the parent event's child list
10171 list_add_tail(&child_event->child_list, &parent_event->child_list);
10172 mutex_unlock(&parent_event->child_mutex);
10174 return child_event;
10177 static int inherit_group(struct perf_event *parent_event,
10178 struct task_struct *parent,
10179 struct perf_event_context *parent_ctx,
10180 struct task_struct *child,
10181 struct perf_event_context *child_ctx)
10183 struct perf_event *leader;
10184 struct perf_event *sub;
10185 struct perf_event *child_ctr;
10187 leader = inherit_event(parent_event, parent, parent_ctx,
10188 child, NULL, child_ctx);
10189 if (IS_ERR(leader))
10190 return PTR_ERR(leader);
10191 list_for_each_entry(sub, &parent_event->sibling_list, group_entry) {
10192 child_ctr = inherit_event(sub, parent, parent_ctx,
10193 child, leader, child_ctx);
10194 if (IS_ERR(child_ctr))
10195 return PTR_ERR(child_ctr);
10201 inherit_task_group(struct perf_event *event, struct task_struct *parent,
10202 struct perf_event_context *parent_ctx,
10203 struct task_struct *child, int ctxn,
10204 int *inherited_all)
10207 struct perf_event_context *child_ctx;
10209 if (!event->attr.inherit) {
10210 *inherited_all = 0;
10214 child_ctx = child->perf_event_ctxp[ctxn];
10217 * This is executed from the parent task context, so
10218 * inherit events that have been marked for cloning.
10219 * First allocate and initialize a context for the
10223 child_ctx = alloc_perf_context(parent_ctx->pmu, child);
10227 child->perf_event_ctxp[ctxn] = child_ctx;
10230 ret = inherit_group(event, parent, parent_ctx,
10234 *inherited_all = 0;
10240 * Initialize the perf_event context in task_struct
10242 static int perf_event_init_context(struct task_struct *child, int ctxn)
10244 struct perf_event_context *child_ctx, *parent_ctx;
10245 struct perf_event_context *cloned_ctx;
10246 struct perf_event *event;
10247 struct task_struct *parent = current;
10248 int inherited_all = 1;
10249 unsigned long flags;
10252 if (likely(!parent->perf_event_ctxp[ctxn]))
10256 * If the parent's context is a clone, pin it so it won't get
10257 * swapped under us.
10259 parent_ctx = perf_pin_task_context(parent, ctxn);
10264 * No need to check if parent_ctx != NULL here; since we saw
10265 * it non-NULL earlier, the only reason for it to become NULL
10266 * is if we exit, and since we're currently in the middle of
10267 * a fork we can't be exiting at the same time.
10271 * Lock the parent list. No need to lock the child - not PID
10272 * hashed yet and not running, so nobody can access it.
10274 mutex_lock(&parent_ctx->mutex);
10277 * We dont have to disable NMIs - we are only looking at
10278 * the list, not manipulating it:
10280 list_for_each_entry(event, &parent_ctx->pinned_groups, group_entry) {
10281 ret = inherit_task_group(event, parent, parent_ctx,
10282 child, ctxn, &inherited_all);
10288 * We can't hold ctx->lock when iterating the ->flexible_group list due
10289 * to allocations, but we need to prevent rotation because
10290 * rotate_ctx() will change the list from interrupt context.
10292 raw_spin_lock_irqsave(&parent_ctx->lock, flags);
10293 parent_ctx->rotate_disable = 1;
10294 raw_spin_unlock_irqrestore(&parent_ctx->lock, flags);
10296 list_for_each_entry(event, &parent_ctx->flexible_groups, group_entry) {
10297 ret = inherit_task_group(event, parent, parent_ctx,
10298 child, ctxn, &inherited_all);
10303 raw_spin_lock_irqsave(&parent_ctx->lock, flags);
10304 parent_ctx->rotate_disable = 0;
10306 child_ctx = child->perf_event_ctxp[ctxn];
10308 if (child_ctx && inherited_all) {
10310 * Mark the child context as a clone of the parent
10311 * context, or of whatever the parent is a clone of.
10313 * Note that if the parent is a clone, the holding of
10314 * parent_ctx->lock avoids it from being uncloned.
10316 cloned_ctx = parent_ctx->parent_ctx;
10318 child_ctx->parent_ctx = cloned_ctx;
10319 child_ctx->parent_gen = parent_ctx->parent_gen;
10321 child_ctx->parent_ctx = parent_ctx;
10322 child_ctx->parent_gen = parent_ctx->generation;
10324 get_ctx(child_ctx->parent_ctx);
10327 raw_spin_unlock_irqrestore(&parent_ctx->lock, flags);
10328 mutex_unlock(&parent_ctx->mutex);
10330 perf_unpin_context(parent_ctx);
10331 put_ctx(parent_ctx);
10337 * Initialize the perf_event context in task_struct
10339 int perf_event_init_task(struct task_struct *child)
10343 memset(child->perf_event_ctxp, 0, sizeof(child->perf_event_ctxp));
10344 mutex_init(&child->perf_event_mutex);
10345 INIT_LIST_HEAD(&child->perf_event_list);
10347 for_each_task_context_nr(ctxn) {
10348 ret = perf_event_init_context(child, ctxn);
10350 perf_event_free_task(child);
10358 static void __init perf_event_init_all_cpus(void)
10360 struct swevent_htable *swhash;
10363 for_each_possible_cpu(cpu) {
10364 swhash = &per_cpu(swevent_htable, cpu);
10365 mutex_init(&swhash->hlist_mutex);
10366 INIT_LIST_HEAD(&per_cpu(active_ctx_list, cpu));
10368 INIT_LIST_HEAD(&per_cpu(pmu_sb_events.list, cpu));
10369 raw_spin_lock_init(&per_cpu(pmu_sb_events.lock, cpu));
10373 int perf_event_init_cpu(unsigned int cpu)
10375 struct swevent_htable *swhash = &per_cpu(swevent_htable, cpu);
10377 mutex_lock(&swhash->hlist_mutex);
10378 if (swhash->hlist_refcount > 0 && !swevent_hlist_deref(swhash)) {
10379 struct swevent_hlist *hlist;
10381 hlist = kzalloc_node(sizeof(*hlist), GFP_KERNEL, cpu_to_node(cpu));
10383 rcu_assign_pointer(swhash->swevent_hlist, hlist);
10385 mutex_unlock(&swhash->hlist_mutex);
10389 #if defined CONFIG_HOTPLUG_CPU || defined CONFIG_KEXEC_CORE
10390 static void __perf_event_exit_context(void *__info)
10392 struct perf_event_context *ctx = __info;
10393 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
10394 struct perf_event *event;
10396 raw_spin_lock(&ctx->lock);
10397 list_for_each_entry(event, &ctx->event_list, event_entry)
10398 __perf_remove_from_context(event, cpuctx, ctx, (void *)DETACH_GROUP);
10399 raw_spin_unlock(&ctx->lock);
10402 static void perf_event_exit_cpu_context(int cpu)
10404 struct perf_event_context *ctx;
10408 idx = srcu_read_lock(&pmus_srcu);
10409 list_for_each_entry_rcu(pmu, &pmus, entry) {
10410 ctx = &per_cpu_ptr(pmu->pmu_cpu_context, cpu)->ctx;
10412 mutex_lock(&ctx->mutex);
10413 smp_call_function_single(cpu, __perf_event_exit_context, ctx, 1);
10414 mutex_unlock(&ctx->mutex);
10416 srcu_read_unlock(&pmus_srcu, idx);
10420 static void perf_event_exit_cpu_context(int cpu) { }
10424 int perf_event_exit_cpu(unsigned int cpu)
10426 perf_event_exit_cpu_context(cpu);
10431 perf_reboot(struct notifier_block *notifier, unsigned long val, void *v)
10435 for_each_online_cpu(cpu)
10436 perf_event_exit_cpu(cpu);
10442 * Run the perf reboot notifier at the very last possible moment so that
10443 * the generic watchdog code runs as long as possible.
10445 static struct notifier_block perf_reboot_notifier = {
10446 .notifier_call = perf_reboot,
10447 .priority = INT_MIN,
10450 void __init perf_event_init(void)
10454 idr_init(&pmu_idr);
10456 perf_event_init_all_cpus();
10457 init_srcu_struct(&pmus_srcu);
10458 perf_pmu_register(&perf_swevent, "software", PERF_TYPE_SOFTWARE);
10459 perf_pmu_register(&perf_cpu_clock, NULL, -1);
10460 perf_pmu_register(&perf_task_clock, NULL, -1);
10461 perf_tp_register();
10462 perf_event_init_cpu(smp_processor_id());
10463 register_reboot_notifier(&perf_reboot_notifier);
10465 ret = init_hw_breakpoint();
10466 WARN(ret, "hw_breakpoint initialization failed with: %d", ret);
10469 * Build time assertion that we keep the data_head at the intended
10470 * location. IOW, validation we got the __reserved[] size right.
10472 BUILD_BUG_ON((offsetof(struct perf_event_mmap_page, data_head))
10476 ssize_t perf_event_sysfs_show(struct device *dev, struct device_attribute *attr,
10479 struct perf_pmu_events_attr *pmu_attr =
10480 container_of(attr, struct perf_pmu_events_attr, attr);
10482 if (pmu_attr->event_str)
10483 return sprintf(page, "%s\n", pmu_attr->event_str);
10487 EXPORT_SYMBOL_GPL(perf_event_sysfs_show);
10489 static int __init perf_event_sysfs_init(void)
10494 mutex_lock(&pmus_lock);
10496 ret = bus_register(&pmu_bus);
10500 list_for_each_entry(pmu, &pmus, entry) {
10501 if (!pmu->name || pmu->type < 0)
10504 ret = pmu_dev_alloc(pmu);
10505 WARN(ret, "Failed to register pmu: %s, reason %d\n", pmu->name, ret);
10507 pmu_bus_running = 1;
10511 mutex_unlock(&pmus_lock);
10515 device_initcall(perf_event_sysfs_init);
10517 #ifdef CONFIG_CGROUP_PERF
10518 static struct cgroup_subsys_state *
10519 perf_cgroup_css_alloc(struct cgroup_subsys_state *parent_css)
10521 struct perf_cgroup *jc;
10523 jc = kzalloc(sizeof(*jc), GFP_KERNEL);
10525 return ERR_PTR(-ENOMEM);
10527 jc->info = alloc_percpu(struct perf_cgroup_info);
10530 return ERR_PTR(-ENOMEM);
10536 static void perf_cgroup_css_free(struct cgroup_subsys_state *css)
10538 struct perf_cgroup *jc = container_of(css, struct perf_cgroup, css);
10540 free_percpu(jc->info);
10544 static int __perf_cgroup_move(void *info)
10546 struct task_struct *task = info;
10548 perf_cgroup_switch(task, PERF_CGROUP_SWOUT | PERF_CGROUP_SWIN);
10553 static void perf_cgroup_attach(struct cgroup_taskset *tset)
10555 struct task_struct *task;
10556 struct cgroup_subsys_state *css;
10558 cgroup_taskset_for_each(task, css, tset)
10559 task_function_call(task, __perf_cgroup_move, task);
10562 struct cgroup_subsys perf_event_cgrp_subsys = {
10563 .css_alloc = perf_cgroup_css_alloc,
10564 .css_free = perf_cgroup_css_free,
10565 .attach = perf_cgroup_attach,
10567 #endif /* CONFIG_CGROUP_PERF */