2 * Performance events core code:
4 * Copyright (C) 2008 Thomas Gleixner <tglx@linutronix.de>
5 * Copyright (C) 2008-2011 Red Hat, Inc., Ingo Molnar
6 * Copyright (C) 2008-2011 Red Hat, Inc., Peter Zijlstra
7 * Copyright © 2009 Paul Mackerras, IBM Corp. <paulus@au1.ibm.com>
9 * For licensing details see kernel-base/COPYING
14 #include <linux/cpu.h>
15 #include <linux/smp.h>
16 #include <linux/idr.h>
17 #include <linux/file.h>
18 #include <linux/poll.h>
19 #include <linux/slab.h>
20 #include <linux/hash.h>
21 #include <linux/tick.h>
22 #include <linux/sysfs.h>
23 #include <linux/dcache.h>
24 #include <linux/percpu.h>
25 #include <linux/ptrace.h>
26 #include <linux/reboot.h>
27 #include <linux/vmstat.h>
28 #include <linux/device.h>
29 #include <linux/export.h>
30 #include <linux/vmalloc.h>
31 #include <linux/hardirq.h>
32 #include <linux/rculist.h>
33 #include <linux/uaccess.h>
34 #include <linux/syscalls.h>
35 #include <linux/anon_inodes.h>
36 #include <linux/kernel_stat.h>
37 #include <linux/cgroup.h>
38 #include <linux/perf_event.h>
39 #include <linux/trace_events.h>
40 #include <linux/hw_breakpoint.h>
41 #include <linux/mm_types.h>
42 #include <linux/module.h>
43 #include <linux/mman.h>
44 #include <linux/compat.h>
45 #include <linux/bpf.h>
46 #include <linux/filter.h>
50 #include <asm/irq_regs.h>
52 typedef int (*remote_function_f)(void *);
54 struct remote_function_call {
55 struct task_struct *p;
56 remote_function_f func;
61 static void remote_function(void *data)
63 struct remote_function_call *tfc = data;
64 struct task_struct *p = tfc->p;
68 if (task_cpu(p) != smp_processor_id())
72 * Now that we're on right CPU with IRQs disabled, we can test
73 * if we hit the right task without races.
76 tfc->ret = -ESRCH; /* No such (running) process */
81 tfc->ret = tfc->func(tfc->info);
85 * task_function_call - call a function on the cpu on which a task runs
86 * @p: the task to evaluate
87 * @func: the function to be called
88 * @info: the function call argument
90 * Calls the function @func when the task is currently running. This might
91 * be on the current CPU, which just calls the function directly
93 * returns: @func return value, or
94 * -ESRCH - when the process isn't running
95 * -EAGAIN - when the process moved away
98 task_function_call(struct task_struct *p, remote_function_f func, void *info)
100 struct remote_function_call data = {
109 ret = smp_call_function_single(task_cpu(p), remote_function, &data, 1);
112 } while (ret == -EAGAIN);
118 * cpu_function_call - call a function on the cpu
119 * @func: the function to be called
120 * @info: the function call argument
122 * Calls the function @func on the remote cpu.
124 * returns: @func return value or -ENXIO when the cpu is offline
126 static int cpu_function_call(int cpu, remote_function_f func, void *info)
128 struct remote_function_call data = {
132 .ret = -ENXIO, /* No such CPU */
135 smp_call_function_single(cpu, remote_function, &data, 1);
140 static inline struct perf_cpu_context *
141 __get_cpu_context(struct perf_event_context *ctx)
143 return this_cpu_ptr(ctx->pmu->pmu_cpu_context);
146 static void perf_ctx_lock(struct perf_cpu_context *cpuctx,
147 struct perf_event_context *ctx)
149 raw_spin_lock(&cpuctx->ctx.lock);
151 raw_spin_lock(&ctx->lock);
154 static void perf_ctx_unlock(struct perf_cpu_context *cpuctx,
155 struct perf_event_context *ctx)
158 raw_spin_unlock(&ctx->lock);
159 raw_spin_unlock(&cpuctx->ctx.lock);
162 #define TASK_TOMBSTONE ((void *)-1L)
164 static bool is_kernel_event(struct perf_event *event)
166 return READ_ONCE(event->owner) == TASK_TOMBSTONE;
170 * On task ctx scheduling...
172 * When !ctx->nr_events a task context will not be scheduled. This means
173 * we can disable the scheduler hooks (for performance) without leaving
174 * pending task ctx state.
176 * This however results in two special cases:
178 * - removing the last event from a task ctx; this is relatively straight
179 * forward and is done in __perf_remove_from_context.
181 * - adding the first event to a task ctx; this is tricky because we cannot
182 * rely on ctx->is_active and therefore cannot use event_function_call().
183 * See perf_install_in_context().
185 * If ctx->nr_events, then ctx->is_active and cpuctx->task_ctx are set.
188 typedef void (*event_f)(struct perf_event *, struct perf_cpu_context *,
189 struct perf_event_context *, void *);
191 struct event_function_struct {
192 struct perf_event *event;
197 static int event_function(void *info)
199 struct event_function_struct *efs = info;
200 struct perf_event *event = efs->event;
201 struct perf_event_context *ctx = event->ctx;
202 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
203 struct perf_event_context *task_ctx = cpuctx->task_ctx;
206 WARN_ON_ONCE(!irqs_disabled());
208 perf_ctx_lock(cpuctx, task_ctx);
210 * Since we do the IPI call without holding ctx->lock things can have
211 * changed, double check we hit the task we set out to hit.
214 if (ctx->task != current) {
220 * We only use event_function_call() on established contexts,
221 * and event_function() is only ever called when active (or
222 * rather, we'll have bailed in task_function_call() or the
223 * above ctx->task != current test), therefore we must have
224 * ctx->is_active here.
226 WARN_ON_ONCE(!ctx->is_active);
228 * And since we have ctx->is_active, cpuctx->task_ctx must
231 WARN_ON_ONCE(task_ctx != ctx);
233 WARN_ON_ONCE(&cpuctx->ctx != ctx);
236 efs->func(event, cpuctx, ctx, efs->data);
238 perf_ctx_unlock(cpuctx, task_ctx);
243 static void event_function_local(struct perf_event *event, event_f func, void *data)
245 struct event_function_struct efs = {
251 int ret = event_function(&efs);
255 static void event_function_call(struct perf_event *event, event_f func, void *data)
257 struct perf_event_context *ctx = event->ctx;
258 struct task_struct *task = READ_ONCE(ctx->task); /* verified in event_function */
259 struct event_function_struct efs = {
265 if (!event->parent) {
267 * If this is a !child event, we must hold ctx::mutex to
268 * stabilize the the event->ctx relation. See
269 * perf_event_ctx_lock().
271 lockdep_assert_held(&ctx->mutex);
275 cpu_function_call(event->cpu, event_function, &efs);
279 if (task == TASK_TOMBSTONE)
283 if (!task_function_call(task, event_function, &efs))
286 raw_spin_lock_irq(&ctx->lock);
288 * Reload the task pointer, it might have been changed by
289 * a concurrent perf_event_context_sched_out().
292 if (task == TASK_TOMBSTONE) {
293 raw_spin_unlock_irq(&ctx->lock);
296 if (ctx->is_active) {
297 raw_spin_unlock_irq(&ctx->lock);
300 func(event, NULL, ctx, data);
301 raw_spin_unlock_irq(&ctx->lock);
304 #define PERF_FLAG_ALL (PERF_FLAG_FD_NO_GROUP |\
305 PERF_FLAG_FD_OUTPUT |\
306 PERF_FLAG_PID_CGROUP |\
307 PERF_FLAG_FD_CLOEXEC)
310 * branch priv levels that need permission checks
312 #define PERF_SAMPLE_BRANCH_PERM_PLM \
313 (PERF_SAMPLE_BRANCH_KERNEL |\
314 PERF_SAMPLE_BRANCH_HV)
317 EVENT_FLEXIBLE = 0x1,
320 EVENT_ALL = EVENT_FLEXIBLE | EVENT_PINNED,
324 * perf_sched_events : >0 events exist
325 * perf_cgroup_events: >0 per-cpu cgroup events exist on this cpu
328 static void perf_sched_delayed(struct work_struct *work);
329 DEFINE_STATIC_KEY_FALSE(perf_sched_events);
330 static DECLARE_DELAYED_WORK(perf_sched_work, perf_sched_delayed);
331 static DEFINE_MUTEX(perf_sched_mutex);
332 static atomic_t perf_sched_count;
334 static DEFINE_PER_CPU(atomic_t, perf_cgroup_events);
335 static DEFINE_PER_CPU(int, perf_sched_cb_usages);
337 static atomic_t nr_mmap_events __read_mostly;
338 static atomic_t nr_comm_events __read_mostly;
339 static atomic_t nr_task_events __read_mostly;
340 static atomic_t nr_freq_events __read_mostly;
341 static atomic_t nr_switch_events __read_mostly;
343 static LIST_HEAD(pmus);
344 static DEFINE_MUTEX(pmus_lock);
345 static struct srcu_struct pmus_srcu;
348 * perf event paranoia level:
349 * -1 - not paranoid at all
350 * 0 - disallow raw tracepoint access for unpriv
351 * 1 - disallow cpu events for unpriv
352 * 2 - disallow kernel profiling for unpriv
354 int sysctl_perf_event_paranoid __read_mostly = 1;
356 /* Minimum for 512 kiB + 1 user control page */
357 int sysctl_perf_event_mlock __read_mostly = 512 + (PAGE_SIZE / 1024); /* 'free' kiB per user */
360 * max perf event sample rate
362 #define DEFAULT_MAX_SAMPLE_RATE 100000
363 #define DEFAULT_SAMPLE_PERIOD_NS (NSEC_PER_SEC / DEFAULT_MAX_SAMPLE_RATE)
364 #define DEFAULT_CPU_TIME_MAX_PERCENT 25
366 int sysctl_perf_event_sample_rate __read_mostly = DEFAULT_MAX_SAMPLE_RATE;
368 static int max_samples_per_tick __read_mostly = DIV_ROUND_UP(DEFAULT_MAX_SAMPLE_RATE, HZ);
369 static int perf_sample_period_ns __read_mostly = DEFAULT_SAMPLE_PERIOD_NS;
371 static int perf_sample_allowed_ns __read_mostly =
372 DEFAULT_SAMPLE_PERIOD_NS * DEFAULT_CPU_TIME_MAX_PERCENT / 100;
374 static void update_perf_cpu_limits(void)
376 u64 tmp = perf_sample_period_ns;
378 tmp *= sysctl_perf_cpu_time_max_percent;
379 tmp = div_u64(tmp, 100);
383 WRITE_ONCE(perf_sample_allowed_ns, tmp);
386 static int perf_rotate_context(struct perf_cpu_context *cpuctx);
388 int perf_proc_update_handler(struct ctl_table *table, int write,
389 void __user *buffer, size_t *lenp,
392 int ret = proc_dointvec_minmax(table, write, buffer, lenp, ppos);
397 max_samples_per_tick = DIV_ROUND_UP(sysctl_perf_event_sample_rate, HZ);
398 perf_sample_period_ns = NSEC_PER_SEC / sysctl_perf_event_sample_rate;
399 update_perf_cpu_limits();
404 int sysctl_perf_cpu_time_max_percent __read_mostly = DEFAULT_CPU_TIME_MAX_PERCENT;
406 int perf_cpu_time_max_percent_handler(struct ctl_table *table, int write,
407 void __user *buffer, size_t *lenp,
410 int ret = proc_dointvec(table, write, buffer, lenp, ppos);
415 if (sysctl_perf_cpu_time_max_percent == 100) {
417 "perf: Dynamic interrupt throttling disabled, can hang your system!\n");
418 WRITE_ONCE(perf_sample_allowed_ns, 0);
420 update_perf_cpu_limits();
427 * perf samples are done in some very critical code paths (NMIs).
428 * If they take too much CPU time, the system can lock up and not
429 * get any real work done. This will drop the sample rate when
430 * we detect that events are taking too long.
432 #define NR_ACCUMULATED_SAMPLES 128
433 static DEFINE_PER_CPU(u64, running_sample_length);
435 static u64 __report_avg;
436 static u64 __report_allowed;
438 static void perf_duration_warn(struct irq_work *w)
440 printk_ratelimited(KERN_WARNING
441 "perf: interrupt took too long (%lld > %lld), lowering "
442 "kernel.perf_event_max_sample_rate to %d\n",
443 __report_avg, __report_allowed,
444 sysctl_perf_event_sample_rate);
447 static DEFINE_IRQ_WORK(perf_duration_work, perf_duration_warn);
449 void perf_sample_event_took(u64 sample_len_ns)
451 u64 max_len = READ_ONCE(perf_sample_allowed_ns);
459 /* Decay the counter by 1 average sample. */
460 running_len = __this_cpu_read(running_sample_length);
461 running_len -= running_len/NR_ACCUMULATED_SAMPLES;
462 running_len += sample_len_ns;
463 __this_cpu_write(running_sample_length, running_len);
466 * Note: this will be biased artifically low until we have
467 * seen NR_ACCUMULATED_SAMPLES. Doing it this way keeps us
468 * from having to maintain a count.
470 avg_len = running_len/NR_ACCUMULATED_SAMPLES;
471 if (avg_len <= max_len)
474 __report_avg = avg_len;
475 __report_allowed = max_len;
478 * Compute a throttle threshold 25% below the current duration.
480 avg_len += avg_len / 4;
481 max = (TICK_NSEC / 100) * sysctl_perf_cpu_time_max_percent;
487 WRITE_ONCE(perf_sample_allowed_ns, avg_len);
488 WRITE_ONCE(max_samples_per_tick, max);
490 sysctl_perf_event_sample_rate = max * HZ;
491 perf_sample_period_ns = NSEC_PER_SEC / sysctl_perf_event_sample_rate;
493 if (!irq_work_queue(&perf_duration_work)) {
494 early_printk("perf: interrupt took too long (%lld > %lld), lowering "
495 "kernel.perf_event_max_sample_rate to %d\n",
496 __report_avg, __report_allowed,
497 sysctl_perf_event_sample_rate);
501 static atomic64_t perf_event_id;
503 static void cpu_ctx_sched_out(struct perf_cpu_context *cpuctx,
504 enum event_type_t event_type);
506 static void cpu_ctx_sched_in(struct perf_cpu_context *cpuctx,
507 enum event_type_t event_type,
508 struct task_struct *task);
510 static void update_context_time(struct perf_event_context *ctx);
511 static u64 perf_event_time(struct perf_event *event);
513 void __weak perf_event_print_debug(void) { }
515 extern __weak const char *perf_pmu_name(void)
520 static inline u64 perf_clock(void)
522 return local_clock();
525 static inline u64 perf_event_clock(struct perf_event *event)
527 return event->clock();
530 #ifdef CONFIG_CGROUP_PERF
533 perf_cgroup_match(struct perf_event *event)
535 struct perf_event_context *ctx = event->ctx;
536 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
538 /* @event doesn't care about cgroup */
542 /* wants specific cgroup scope but @cpuctx isn't associated with any */
547 * Cgroup scoping is recursive. An event enabled for a cgroup is
548 * also enabled for all its descendant cgroups. If @cpuctx's
549 * cgroup is a descendant of @event's (the test covers identity
550 * case), it's a match.
552 return cgroup_is_descendant(cpuctx->cgrp->css.cgroup,
553 event->cgrp->css.cgroup);
556 static inline void perf_detach_cgroup(struct perf_event *event)
558 css_put(&event->cgrp->css);
562 static inline int is_cgroup_event(struct perf_event *event)
564 return event->cgrp != NULL;
567 static inline u64 perf_cgroup_event_time(struct perf_event *event)
569 struct perf_cgroup_info *t;
571 t = per_cpu_ptr(event->cgrp->info, event->cpu);
575 static inline void __update_cgrp_time(struct perf_cgroup *cgrp)
577 struct perf_cgroup_info *info;
582 info = this_cpu_ptr(cgrp->info);
584 info->time += now - info->timestamp;
585 info->timestamp = now;
588 static inline void update_cgrp_time_from_cpuctx(struct perf_cpu_context *cpuctx)
590 struct perf_cgroup *cgrp_out = cpuctx->cgrp;
592 __update_cgrp_time(cgrp_out);
595 static inline void update_cgrp_time_from_event(struct perf_event *event)
597 struct perf_cgroup *cgrp;
600 * ensure we access cgroup data only when needed and
601 * when we know the cgroup is pinned (css_get)
603 if (!is_cgroup_event(event))
606 cgrp = perf_cgroup_from_task(current, event->ctx);
608 * Do not update time when cgroup is not active
610 if (cgrp == event->cgrp)
611 __update_cgrp_time(event->cgrp);
615 perf_cgroup_set_timestamp(struct task_struct *task,
616 struct perf_event_context *ctx)
618 struct perf_cgroup *cgrp;
619 struct perf_cgroup_info *info;
622 * ctx->lock held by caller
623 * ensure we do not access cgroup data
624 * unless we have the cgroup pinned (css_get)
626 if (!task || !ctx->nr_cgroups)
629 cgrp = perf_cgroup_from_task(task, ctx);
630 info = this_cpu_ptr(cgrp->info);
631 info->timestamp = ctx->timestamp;
634 #define PERF_CGROUP_SWOUT 0x1 /* cgroup switch out every event */
635 #define PERF_CGROUP_SWIN 0x2 /* cgroup switch in events based on task */
638 * reschedule events based on the cgroup constraint of task.
640 * mode SWOUT : schedule out everything
641 * mode SWIN : schedule in based on cgroup for next
643 static void perf_cgroup_switch(struct task_struct *task, int mode)
645 struct perf_cpu_context *cpuctx;
650 * disable interrupts to avoid geting nr_cgroup
651 * changes via __perf_event_disable(). Also
654 local_irq_save(flags);
657 * we reschedule only in the presence of cgroup
658 * constrained events.
661 list_for_each_entry_rcu(pmu, &pmus, entry) {
662 cpuctx = this_cpu_ptr(pmu->pmu_cpu_context);
663 if (cpuctx->unique_pmu != pmu)
664 continue; /* ensure we process each cpuctx once */
667 * perf_cgroup_events says at least one
668 * context on this CPU has cgroup events.
670 * ctx->nr_cgroups reports the number of cgroup
671 * events for a context.
673 if (cpuctx->ctx.nr_cgroups > 0) {
674 perf_ctx_lock(cpuctx, cpuctx->task_ctx);
675 perf_pmu_disable(cpuctx->ctx.pmu);
677 if (mode & PERF_CGROUP_SWOUT) {
678 cpu_ctx_sched_out(cpuctx, EVENT_ALL);
680 * must not be done before ctxswout due
681 * to event_filter_match() in event_sched_out()
686 if (mode & PERF_CGROUP_SWIN) {
687 WARN_ON_ONCE(cpuctx->cgrp);
689 * set cgrp before ctxsw in to allow
690 * event_filter_match() to not have to pass
692 * we pass the cpuctx->ctx to perf_cgroup_from_task()
693 * because cgorup events are only per-cpu
695 cpuctx->cgrp = perf_cgroup_from_task(task, &cpuctx->ctx);
696 cpu_ctx_sched_in(cpuctx, EVENT_ALL, task);
698 perf_pmu_enable(cpuctx->ctx.pmu);
699 perf_ctx_unlock(cpuctx, cpuctx->task_ctx);
703 local_irq_restore(flags);
706 static inline void perf_cgroup_sched_out(struct task_struct *task,
707 struct task_struct *next)
709 struct perf_cgroup *cgrp1;
710 struct perf_cgroup *cgrp2 = NULL;
714 * we come here when we know perf_cgroup_events > 0
715 * we do not need to pass the ctx here because we know
716 * we are holding the rcu lock
718 cgrp1 = perf_cgroup_from_task(task, NULL);
719 cgrp2 = perf_cgroup_from_task(next, NULL);
722 * only schedule out current cgroup events if we know
723 * that we are switching to a different cgroup. Otherwise,
724 * do no touch the cgroup events.
727 perf_cgroup_switch(task, PERF_CGROUP_SWOUT);
732 static inline void perf_cgroup_sched_in(struct task_struct *prev,
733 struct task_struct *task)
735 struct perf_cgroup *cgrp1;
736 struct perf_cgroup *cgrp2 = NULL;
740 * we come here when we know perf_cgroup_events > 0
741 * we do not need to pass the ctx here because we know
742 * we are holding the rcu lock
744 cgrp1 = perf_cgroup_from_task(task, NULL);
745 cgrp2 = perf_cgroup_from_task(prev, NULL);
748 * only need to schedule in cgroup events if we are changing
749 * cgroup during ctxsw. Cgroup events were not scheduled
750 * out of ctxsw out if that was not the case.
753 perf_cgroup_switch(task, PERF_CGROUP_SWIN);
758 static inline int perf_cgroup_connect(int fd, struct perf_event *event,
759 struct perf_event_attr *attr,
760 struct perf_event *group_leader)
762 struct perf_cgroup *cgrp;
763 struct cgroup_subsys_state *css;
764 struct fd f = fdget(fd);
770 css = css_tryget_online_from_dir(f.file->f_path.dentry,
771 &perf_event_cgrp_subsys);
777 cgrp = container_of(css, struct perf_cgroup, css);
781 * all events in a group must monitor
782 * the same cgroup because a task belongs
783 * to only one perf cgroup at a time
785 if (group_leader && group_leader->cgrp != cgrp) {
786 perf_detach_cgroup(event);
795 perf_cgroup_set_shadow_time(struct perf_event *event, u64 now)
797 struct perf_cgroup_info *t;
798 t = per_cpu_ptr(event->cgrp->info, event->cpu);
799 event->shadow_ctx_time = now - t->timestamp;
803 perf_cgroup_defer_enabled(struct perf_event *event)
806 * when the current task's perf cgroup does not match
807 * the event's, we need to remember to call the
808 * perf_mark_enable() function the first time a task with
809 * a matching perf cgroup is scheduled in.
811 if (is_cgroup_event(event) && !perf_cgroup_match(event))
812 event->cgrp_defer_enabled = 1;
816 perf_cgroup_mark_enabled(struct perf_event *event,
817 struct perf_event_context *ctx)
819 struct perf_event *sub;
820 u64 tstamp = perf_event_time(event);
822 if (!event->cgrp_defer_enabled)
825 event->cgrp_defer_enabled = 0;
827 event->tstamp_enabled = tstamp - event->total_time_enabled;
828 list_for_each_entry(sub, &event->sibling_list, group_entry) {
829 if (sub->state >= PERF_EVENT_STATE_INACTIVE) {
830 sub->tstamp_enabled = tstamp - sub->total_time_enabled;
831 sub->cgrp_defer_enabled = 0;
835 #else /* !CONFIG_CGROUP_PERF */
838 perf_cgroup_match(struct perf_event *event)
843 static inline void perf_detach_cgroup(struct perf_event *event)
846 static inline int is_cgroup_event(struct perf_event *event)
851 static inline u64 perf_cgroup_event_cgrp_time(struct perf_event *event)
856 static inline void update_cgrp_time_from_event(struct perf_event *event)
860 static inline void update_cgrp_time_from_cpuctx(struct perf_cpu_context *cpuctx)
864 static inline void perf_cgroup_sched_out(struct task_struct *task,
865 struct task_struct *next)
869 static inline void perf_cgroup_sched_in(struct task_struct *prev,
870 struct task_struct *task)
874 static inline int perf_cgroup_connect(pid_t pid, struct perf_event *event,
875 struct perf_event_attr *attr,
876 struct perf_event *group_leader)
882 perf_cgroup_set_timestamp(struct task_struct *task,
883 struct perf_event_context *ctx)
888 perf_cgroup_switch(struct task_struct *task, struct task_struct *next)
893 perf_cgroup_set_shadow_time(struct perf_event *event, u64 now)
897 static inline u64 perf_cgroup_event_time(struct perf_event *event)
903 perf_cgroup_defer_enabled(struct perf_event *event)
908 perf_cgroup_mark_enabled(struct perf_event *event,
909 struct perf_event_context *ctx)
915 * set default to be dependent on timer tick just
918 #define PERF_CPU_HRTIMER (1000 / HZ)
920 * function must be called with interrupts disbled
922 static enum hrtimer_restart perf_mux_hrtimer_handler(struct hrtimer *hr)
924 struct perf_cpu_context *cpuctx;
927 WARN_ON(!irqs_disabled());
929 cpuctx = container_of(hr, struct perf_cpu_context, hrtimer);
930 rotations = perf_rotate_context(cpuctx);
932 raw_spin_lock(&cpuctx->hrtimer_lock);
934 hrtimer_forward_now(hr, cpuctx->hrtimer_interval);
936 cpuctx->hrtimer_active = 0;
937 raw_spin_unlock(&cpuctx->hrtimer_lock);
939 return rotations ? HRTIMER_RESTART : HRTIMER_NORESTART;
942 static void __perf_mux_hrtimer_init(struct perf_cpu_context *cpuctx, int cpu)
944 struct hrtimer *timer = &cpuctx->hrtimer;
945 struct pmu *pmu = cpuctx->ctx.pmu;
948 /* no multiplexing needed for SW PMU */
949 if (pmu->task_ctx_nr == perf_sw_context)
953 * check default is sane, if not set then force to
954 * default interval (1/tick)
956 interval = pmu->hrtimer_interval_ms;
958 interval = pmu->hrtimer_interval_ms = PERF_CPU_HRTIMER;
960 cpuctx->hrtimer_interval = ns_to_ktime(NSEC_PER_MSEC * interval);
962 raw_spin_lock_init(&cpuctx->hrtimer_lock);
963 hrtimer_init(timer, CLOCK_MONOTONIC, HRTIMER_MODE_ABS_PINNED);
964 timer->function = perf_mux_hrtimer_handler;
967 static int perf_mux_hrtimer_restart(struct perf_cpu_context *cpuctx)
969 struct hrtimer *timer = &cpuctx->hrtimer;
970 struct pmu *pmu = cpuctx->ctx.pmu;
974 if (pmu->task_ctx_nr == perf_sw_context)
977 raw_spin_lock_irqsave(&cpuctx->hrtimer_lock, flags);
978 if (!cpuctx->hrtimer_active) {
979 cpuctx->hrtimer_active = 1;
980 hrtimer_forward_now(timer, cpuctx->hrtimer_interval);
981 hrtimer_start_expires(timer, HRTIMER_MODE_ABS_PINNED);
983 raw_spin_unlock_irqrestore(&cpuctx->hrtimer_lock, flags);
988 void perf_pmu_disable(struct pmu *pmu)
990 int *count = this_cpu_ptr(pmu->pmu_disable_count);
992 pmu->pmu_disable(pmu);
995 void perf_pmu_enable(struct pmu *pmu)
997 int *count = this_cpu_ptr(pmu->pmu_disable_count);
999 pmu->pmu_enable(pmu);
1002 static DEFINE_PER_CPU(struct list_head, active_ctx_list);
1005 * perf_event_ctx_activate(), perf_event_ctx_deactivate(), and
1006 * perf_event_task_tick() are fully serialized because they're strictly cpu
1007 * affine and perf_event_ctx{activate,deactivate} are called with IRQs
1008 * disabled, while perf_event_task_tick is called from IRQ context.
1010 static void perf_event_ctx_activate(struct perf_event_context *ctx)
1012 struct list_head *head = this_cpu_ptr(&active_ctx_list);
1014 WARN_ON(!irqs_disabled());
1016 WARN_ON(!list_empty(&ctx->active_ctx_list));
1018 list_add(&ctx->active_ctx_list, head);
1021 static void perf_event_ctx_deactivate(struct perf_event_context *ctx)
1023 WARN_ON(!irqs_disabled());
1025 WARN_ON(list_empty(&ctx->active_ctx_list));
1027 list_del_init(&ctx->active_ctx_list);
1030 static void get_ctx(struct perf_event_context *ctx)
1032 WARN_ON(!atomic_inc_not_zero(&ctx->refcount));
1035 static void free_ctx(struct rcu_head *head)
1037 struct perf_event_context *ctx;
1039 ctx = container_of(head, struct perf_event_context, rcu_head);
1040 kfree(ctx->task_ctx_data);
1044 static void put_ctx(struct perf_event_context *ctx)
1046 if (atomic_dec_and_test(&ctx->refcount)) {
1047 if (ctx->parent_ctx)
1048 put_ctx(ctx->parent_ctx);
1049 if (ctx->task && ctx->task != TASK_TOMBSTONE)
1050 put_task_struct(ctx->task);
1051 call_rcu(&ctx->rcu_head, free_ctx);
1056 * Because of perf_event::ctx migration in sys_perf_event_open::move_group and
1057 * perf_pmu_migrate_context() we need some magic.
1059 * Those places that change perf_event::ctx will hold both
1060 * perf_event_ctx::mutex of the 'old' and 'new' ctx value.
1062 * Lock ordering is by mutex address. There are two other sites where
1063 * perf_event_context::mutex nests and those are:
1065 * - perf_event_exit_task_context() [ child , 0 ]
1066 * perf_event_exit_event()
1067 * put_event() [ parent, 1 ]
1069 * - perf_event_init_context() [ parent, 0 ]
1070 * inherit_task_group()
1073 * perf_event_alloc()
1075 * perf_try_init_event() [ child , 1 ]
1077 * While it appears there is an obvious deadlock here -- the parent and child
1078 * nesting levels are inverted between the two. This is in fact safe because
1079 * life-time rules separate them. That is an exiting task cannot fork, and a
1080 * spawning task cannot (yet) exit.
1082 * But remember that that these are parent<->child context relations, and
1083 * migration does not affect children, therefore these two orderings should not
1086 * The change in perf_event::ctx does not affect children (as claimed above)
1087 * because the sys_perf_event_open() case will install a new event and break
1088 * the ctx parent<->child relation, and perf_pmu_migrate_context() is only
1089 * concerned with cpuctx and that doesn't have children.
1091 * The places that change perf_event::ctx will issue:
1093 * perf_remove_from_context();
1094 * synchronize_rcu();
1095 * perf_install_in_context();
1097 * to affect the change. The remove_from_context() + synchronize_rcu() should
1098 * quiesce the event, after which we can install it in the new location. This
1099 * means that only external vectors (perf_fops, prctl) can perturb the event
1100 * while in transit. Therefore all such accessors should also acquire
1101 * perf_event_context::mutex to serialize against this.
1103 * However; because event->ctx can change while we're waiting to acquire
1104 * ctx->mutex we must be careful and use the below perf_event_ctx_lock()
1108 * task_struct::perf_event_mutex
1109 * perf_event_context::mutex
1110 * perf_event::child_mutex;
1111 * perf_event_context::lock
1112 * perf_event::mmap_mutex
1115 static struct perf_event_context *
1116 perf_event_ctx_lock_nested(struct perf_event *event, int nesting)
1118 struct perf_event_context *ctx;
1122 ctx = ACCESS_ONCE(event->ctx);
1123 if (!atomic_inc_not_zero(&ctx->refcount)) {
1129 mutex_lock_nested(&ctx->mutex, nesting);
1130 if (event->ctx != ctx) {
1131 mutex_unlock(&ctx->mutex);
1139 static inline struct perf_event_context *
1140 perf_event_ctx_lock(struct perf_event *event)
1142 return perf_event_ctx_lock_nested(event, 0);
1145 static void perf_event_ctx_unlock(struct perf_event *event,
1146 struct perf_event_context *ctx)
1148 mutex_unlock(&ctx->mutex);
1153 * This must be done under the ctx->lock, such as to serialize against
1154 * context_equiv(), therefore we cannot call put_ctx() since that might end up
1155 * calling scheduler related locks and ctx->lock nests inside those.
1157 static __must_check struct perf_event_context *
1158 unclone_ctx(struct perf_event_context *ctx)
1160 struct perf_event_context *parent_ctx = ctx->parent_ctx;
1162 lockdep_assert_held(&ctx->lock);
1165 ctx->parent_ctx = NULL;
1171 static u32 perf_event_pid(struct perf_event *event, struct task_struct *p)
1174 * only top level events have the pid namespace they were created in
1177 event = event->parent;
1179 return task_tgid_nr_ns(p, event->ns);
1182 static u32 perf_event_tid(struct perf_event *event, struct task_struct *p)
1185 * only top level events have the pid namespace they were created in
1188 event = event->parent;
1190 return task_pid_nr_ns(p, event->ns);
1194 * If we inherit events we want to return the parent event id
1197 static u64 primary_event_id(struct perf_event *event)
1202 id = event->parent->id;
1208 * Get the perf_event_context for a task and lock it.
1210 * This has to cope with with the fact that until it is locked,
1211 * the context could get moved to another task.
1213 static struct perf_event_context *
1214 perf_lock_task_context(struct task_struct *task, int ctxn, unsigned long *flags)
1216 struct perf_event_context *ctx;
1220 * One of the few rules of preemptible RCU is that one cannot do
1221 * rcu_read_unlock() while holding a scheduler (or nested) lock when
1222 * part of the read side critical section was irqs-enabled -- see
1223 * rcu_read_unlock_special().
1225 * Since ctx->lock nests under rq->lock we must ensure the entire read
1226 * side critical section has interrupts disabled.
1228 local_irq_save(*flags);
1230 ctx = rcu_dereference(task->perf_event_ctxp[ctxn]);
1233 * If this context is a clone of another, it might
1234 * get swapped for another underneath us by
1235 * perf_event_task_sched_out, though the
1236 * rcu_read_lock() protects us from any context
1237 * getting freed. Lock the context and check if it
1238 * got swapped before we could get the lock, and retry
1239 * if so. If we locked the right context, then it
1240 * can't get swapped on us any more.
1242 raw_spin_lock(&ctx->lock);
1243 if (ctx != rcu_dereference(task->perf_event_ctxp[ctxn])) {
1244 raw_spin_unlock(&ctx->lock);
1246 local_irq_restore(*flags);
1250 if (ctx->task == TASK_TOMBSTONE ||
1251 !atomic_inc_not_zero(&ctx->refcount)) {
1252 raw_spin_unlock(&ctx->lock);
1255 WARN_ON_ONCE(ctx->task != task);
1260 local_irq_restore(*flags);
1265 * Get the context for a task and increment its pin_count so it
1266 * can't get swapped to another task. This also increments its
1267 * reference count so that the context can't get freed.
1269 static struct perf_event_context *
1270 perf_pin_task_context(struct task_struct *task, int ctxn)
1272 struct perf_event_context *ctx;
1273 unsigned long flags;
1275 ctx = perf_lock_task_context(task, ctxn, &flags);
1278 raw_spin_unlock_irqrestore(&ctx->lock, flags);
1283 static void perf_unpin_context(struct perf_event_context *ctx)
1285 unsigned long flags;
1287 raw_spin_lock_irqsave(&ctx->lock, flags);
1289 raw_spin_unlock_irqrestore(&ctx->lock, flags);
1293 * Update the record of the current time in a context.
1295 static void update_context_time(struct perf_event_context *ctx)
1297 u64 now = perf_clock();
1299 ctx->time += now - ctx->timestamp;
1300 ctx->timestamp = now;
1303 static u64 perf_event_time(struct perf_event *event)
1305 struct perf_event_context *ctx = event->ctx;
1307 if (is_cgroup_event(event))
1308 return perf_cgroup_event_time(event);
1310 return ctx ? ctx->time : 0;
1314 * Update the total_time_enabled and total_time_running fields for a event.
1316 static void update_event_times(struct perf_event *event)
1318 struct perf_event_context *ctx = event->ctx;
1321 lockdep_assert_held(&ctx->lock);
1323 if (event->state < PERF_EVENT_STATE_INACTIVE ||
1324 event->group_leader->state < PERF_EVENT_STATE_INACTIVE)
1328 * in cgroup mode, time_enabled represents
1329 * the time the event was enabled AND active
1330 * tasks were in the monitored cgroup. This is
1331 * independent of the activity of the context as
1332 * there may be a mix of cgroup and non-cgroup events.
1334 * That is why we treat cgroup events differently
1337 if (is_cgroup_event(event))
1338 run_end = perf_cgroup_event_time(event);
1339 else if (ctx->is_active)
1340 run_end = ctx->time;
1342 run_end = event->tstamp_stopped;
1344 event->total_time_enabled = run_end - event->tstamp_enabled;
1346 if (event->state == PERF_EVENT_STATE_INACTIVE)
1347 run_end = event->tstamp_stopped;
1349 run_end = perf_event_time(event);
1351 event->total_time_running = run_end - event->tstamp_running;
1356 * Update total_time_enabled and total_time_running for all events in a group.
1358 static void update_group_times(struct perf_event *leader)
1360 struct perf_event *event;
1362 update_event_times(leader);
1363 list_for_each_entry(event, &leader->sibling_list, group_entry)
1364 update_event_times(event);
1367 static struct list_head *
1368 ctx_group_list(struct perf_event *event, struct perf_event_context *ctx)
1370 if (event->attr.pinned)
1371 return &ctx->pinned_groups;
1373 return &ctx->flexible_groups;
1377 * Add a event from the lists for its context.
1378 * Must be called with ctx->mutex and ctx->lock held.
1381 list_add_event(struct perf_event *event, struct perf_event_context *ctx)
1383 lockdep_assert_held(&ctx->lock);
1385 WARN_ON_ONCE(event->attach_state & PERF_ATTACH_CONTEXT);
1386 event->attach_state |= PERF_ATTACH_CONTEXT;
1389 * If we're a stand alone event or group leader, we go to the context
1390 * list, group events are kept attached to the group so that
1391 * perf_group_detach can, at all times, locate all siblings.
1393 if (event->group_leader == event) {
1394 struct list_head *list;
1396 if (is_software_event(event))
1397 event->group_flags |= PERF_GROUP_SOFTWARE;
1399 list = ctx_group_list(event, ctx);
1400 list_add_tail(&event->group_entry, list);
1403 if (is_cgroup_event(event))
1406 list_add_rcu(&event->event_entry, &ctx->event_list);
1408 if (event->attr.inherit_stat)
1415 * Initialize event state based on the perf_event_attr::disabled.
1417 static inline void perf_event__state_init(struct perf_event *event)
1419 event->state = event->attr.disabled ? PERF_EVENT_STATE_OFF :
1420 PERF_EVENT_STATE_INACTIVE;
1423 static void __perf_event_read_size(struct perf_event *event, int nr_siblings)
1425 int entry = sizeof(u64); /* value */
1429 if (event->attr.read_format & PERF_FORMAT_TOTAL_TIME_ENABLED)
1430 size += sizeof(u64);
1432 if (event->attr.read_format & PERF_FORMAT_TOTAL_TIME_RUNNING)
1433 size += sizeof(u64);
1435 if (event->attr.read_format & PERF_FORMAT_ID)
1436 entry += sizeof(u64);
1438 if (event->attr.read_format & PERF_FORMAT_GROUP) {
1440 size += sizeof(u64);
1444 event->read_size = size;
1447 static void __perf_event_header_size(struct perf_event *event, u64 sample_type)
1449 struct perf_sample_data *data;
1452 if (sample_type & PERF_SAMPLE_IP)
1453 size += sizeof(data->ip);
1455 if (sample_type & PERF_SAMPLE_ADDR)
1456 size += sizeof(data->addr);
1458 if (sample_type & PERF_SAMPLE_PERIOD)
1459 size += sizeof(data->period);
1461 if (sample_type & PERF_SAMPLE_WEIGHT)
1462 size += sizeof(data->weight);
1464 if (sample_type & PERF_SAMPLE_READ)
1465 size += event->read_size;
1467 if (sample_type & PERF_SAMPLE_DATA_SRC)
1468 size += sizeof(data->data_src.val);
1470 if (sample_type & PERF_SAMPLE_TRANSACTION)
1471 size += sizeof(data->txn);
1473 event->header_size = size;
1477 * Called at perf_event creation and when events are attached/detached from a
1480 static void perf_event__header_size(struct perf_event *event)
1482 __perf_event_read_size(event,
1483 event->group_leader->nr_siblings);
1484 __perf_event_header_size(event, event->attr.sample_type);
1487 static void perf_event__id_header_size(struct perf_event *event)
1489 struct perf_sample_data *data;
1490 u64 sample_type = event->attr.sample_type;
1493 if (sample_type & PERF_SAMPLE_TID)
1494 size += sizeof(data->tid_entry);
1496 if (sample_type & PERF_SAMPLE_TIME)
1497 size += sizeof(data->time);
1499 if (sample_type & PERF_SAMPLE_IDENTIFIER)
1500 size += sizeof(data->id);
1502 if (sample_type & PERF_SAMPLE_ID)
1503 size += sizeof(data->id);
1505 if (sample_type & PERF_SAMPLE_STREAM_ID)
1506 size += sizeof(data->stream_id);
1508 if (sample_type & PERF_SAMPLE_CPU)
1509 size += sizeof(data->cpu_entry);
1511 event->id_header_size = size;
1514 static bool perf_event_validate_size(struct perf_event *event)
1517 * The values computed here will be over-written when we actually
1520 __perf_event_read_size(event, event->group_leader->nr_siblings + 1);
1521 __perf_event_header_size(event, event->attr.sample_type & ~PERF_SAMPLE_READ);
1522 perf_event__id_header_size(event);
1525 * Sum the lot; should not exceed the 64k limit we have on records.
1526 * Conservative limit to allow for callchains and other variable fields.
1528 if (event->read_size + event->header_size +
1529 event->id_header_size + sizeof(struct perf_event_header) >= 16*1024)
1535 static void perf_group_attach(struct perf_event *event)
1537 struct perf_event *group_leader = event->group_leader, *pos;
1540 * We can have double attach due to group movement in perf_event_open.
1542 if (event->attach_state & PERF_ATTACH_GROUP)
1545 event->attach_state |= PERF_ATTACH_GROUP;
1547 if (group_leader == event)
1550 WARN_ON_ONCE(group_leader->ctx != event->ctx);
1552 if (group_leader->group_flags & PERF_GROUP_SOFTWARE &&
1553 !is_software_event(event))
1554 group_leader->group_flags &= ~PERF_GROUP_SOFTWARE;
1556 list_add_tail(&event->group_entry, &group_leader->sibling_list);
1557 group_leader->nr_siblings++;
1559 perf_event__header_size(group_leader);
1561 list_for_each_entry(pos, &group_leader->sibling_list, group_entry)
1562 perf_event__header_size(pos);
1566 * Remove a event from the lists for its context.
1567 * Must be called with ctx->mutex and ctx->lock held.
1570 list_del_event(struct perf_event *event, struct perf_event_context *ctx)
1572 struct perf_cpu_context *cpuctx;
1574 WARN_ON_ONCE(event->ctx != ctx);
1575 lockdep_assert_held(&ctx->lock);
1578 * We can have double detach due to exit/hot-unplug + close.
1580 if (!(event->attach_state & PERF_ATTACH_CONTEXT))
1583 event->attach_state &= ~PERF_ATTACH_CONTEXT;
1585 if (is_cgroup_event(event)) {
1588 * Because cgroup events are always per-cpu events, this will
1589 * always be called from the right CPU.
1591 cpuctx = __get_cpu_context(ctx);
1593 * If there are no more cgroup events then clear cgrp to avoid
1594 * stale pointer in update_cgrp_time_from_cpuctx().
1596 if (!ctx->nr_cgroups)
1597 cpuctx->cgrp = NULL;
1601 if (event->attr.inherit_stat)
1604 list_del_rcu(&event->event_entry);
1606 if (event->group_leader == event)
1607 list_del_init(&event->group_entry);
1609 update_group_times(event);
1612 * If event was in error state, then keep it
1613 * that way, otherwise bogus counts will be
1614 * returned on read(). The only way to get out
1615 * of error state is by explicit re-enabling
1618 if (event->state > PERF_EVENT_STATE_OFF)
1619 event->state = PERF_EVENT_STATE_OFF;
1624 static void perf_group_detach(struct perf_event *event)
1626 struct perf_event *sibling, *tmp;
1627 struct list_head *list = NULL;
1630 * We can have double detach due to exit/hot-unplug + close.
1632 if (!(event->attach_state & PERF_ATTACH_GROUP))
1635 event->attach_state &= ~PERF_ATTACH_GROUP;
1638 * If this is a sibling, remove it from its group.
1640 if (event->group_leader != event) {
1641 list_del_init(&event->group_entry);
1642 event->group_leader->nr_siblings--;
1646 if (!list_empty(&event->group_entry))
1647 list = &event->group_entry;
1650 * If this was a group event with sibling events then
1651 * upgrade the siblings to singleton events by adding them
1652 * to whatever list we are on.
1654 list_for_each_entry_safe(sibling, tmp, &event->sibling_list, group_entry) {
1656 list_move_tail(&sibling->group_entry, list);
1657 sibling->group_leader = sibling;
1659 /* Inherit group flags from the previous leader */
1660 sibling->group_flags = event->group_flags;
1662 WARN_ON_ONCE(sibling->ctx != event->ctx);
1666 perf_event__header_size(event->group_leader);
1668 list_for_each_entry(tmp, &event->group_leader->sibling_list, group_entry)
1669 perf_event__header_size(tmp);
1672 static bool is_orphaned_event(struct perf_event *event)
1674 return event->state == PERF_EVENT_STATE_DEAD;
1677 static inline int pmu_filter_match(struct perf_event *event)
1679 struct pmu *pmu = event->pmu;
1680 return pmu->filter_match ? pmu->filter_match(event) : 1;
1684 event_filter_match(struct perf_event *event)
1686 return (event->cpu == -1 || event->cpu == smp_processor_id())
1687 && perf_cgroup_match(event) && pmu_filter_match(event);
1691 event_sched_out(struct perf_event *event,
1692 struct perf_cpu_context *cpuctx,
1693 struct perf_event_context *ctx)
1695 u64 tstamp = perf_event_time(event);
1698 WARN_ON_ONCE(event->ctx != ctx);
1699 lockdep_assert_held(&ctx->lock);
1702 * An event which could not be activated because of
1703 * filter mismatch still needs to have its timings
1704 * maintained, otherwise bogus information is return
1705 * via read() for time_enabled, time_running:
1707 if (event->state == PERF_EVENT_STATE_INACTIVE
1708 && !event_filter_match(event)) {
1709 delta = tstamp - event->tstamp_stopped;
1710 event->tstamp_running += delta;
1711 event->tstamp_stopped = tstamp;
1714 if (event->state != PERF_EVENT_STATE_ACTIVE)
1717 perf_pmu_disable(event->pmu);
1719 event->tstamp_stopped = tstamp;
1720 event->pmu->del(event, 0);
1722 event->state = PERF_EVENT_STATE_INACTIVE;
1723 if (event->pending_disable) {
1724 event->pending_disable = 0;
1725 event->state = PERF_EVENT_STATE_OFF;
1728 if (!is_software_event(event))
1729 cpuctx->active_oncpu--;
1730 if (!--ctx->nr_active)
1731 perf_event_ctx_deactivate(ctx);
1732 if (event->attr.freq && event->attr.sample_freq)
1734 if (event->attr.exclusive || !cpuctx->active_oncpu)
1735 cpuctx->exclusive = 0;
1737 perf_pmu_enable(event->pmu);
1741 group_sched_out(struct perf_event *group_event,
1742 struct perf_cpu_context *cpuctx,
1743 struct perf_event_context *ctx)
1745 struct perf_event *event;
1746 int state = group_event->state;
1748 event_sched_out(group_event, cpuctx, ctx);
1751 * Schedule out siblings (if any):
1753 list_for_each_entry(event, &group_event->sibling_list, group_entry)
1754 event_sched_out(event, cpuctx, ctx);
1756 if (state == PERF_EVENT_STATE_ACTIVE && group_event->attr.exclusive)
1757 cpuctx->exclusive = 0;
1760 #define DETACH_GROUP 0x01UL
1763 * Cross CPU call to remove a performance event
1765 * We disable the event on the hardware level first. After that we
1766 * remove it from the context list.
1769 __perf_remove_from_context(struct perf_event *event,
1770 struct perf_cpu_context *cpuctx,
1771 struct perf_event_context *ctx,
1774 unsigned long flags = (unsigned long)info;
1776 event_sched_out(event, cpuctx, ctx);
1777 if (flags & DETACH_GROUP)
1778 perf_group_detach(event);
1779 list_del_event(event, ctx);
1781 if (!ctx->nr_events && ctx->is_active) {
1784 WARN_ON_ONCE(cpuctx->task_ctx != ctx);
1785 cpuctx->task_ctx = NULL;
1791 * Remove the event from a task's (or a CPU's) list of events.
1793 * If event->ctx is a cloned context, callers must make sure that
1794 * every task struct that event->ctx->task could possibly point to
1795 * remains valid. This is OK when called from perf_release since
1796 * that only calls us on the top-level context, which can't be a clone.
1797 * When called from perf_event_exit_task, it's OK because the
1798 * context has been detached from its task.
1800 static void perf_remove_from_context(struct perf_event *event, unsigned long flags)
1802 lockdep_assert_held(&event->ctx->mutex);
1804 event_function_call(event, __perf_remove_from_context, (void *)flags);
1808 * Cross CPU call to disable a performance event
1810 static void __perf_event_disable(struct perf_event *event,
1811 struct perf_cpu_context *cpuctx,
1812 struct perf_event_context *ctx,
1815 if (event->state < PERF_EVENT_STATE_INACTIVE)
1818 update_context_time(ctx);
1819 update_cgrp_time_from_event(event);
1820 update_group_times(event);
1821 if (event == event->group_leader)
1822 group_sched_out(event, cpuctx, ctx);
1824 event_sched_out(event, cpuctx, ctx);
1825 event->state = PERF_EVENT_STATE_OFF;
1831 * If event->ctx is a cloned context, callers must make sure that
1832 * every task struct that event->ctx->task could possibly point to
1833 * remains valid. This condition is satisifed when called through
1834 * perf_event_for_each_child or perf_event_for_each because they
1835 * hold the top-level event's child_mutex, so any descendant that
1836 * goes to exit will block in perf_event_exit_event().
1838 * When called from perf_pending_event it's OK because event->ctx
1839 * is the current context on this CPU and preemption is disabled,
1840 * hence we can't get into perf_event_task_sched_out for this context.
1842 static void _perf_event_disable(struct perf_event *event)
1844 struct perf_event_context *ctx = event->ctx;
1846 raw_spin_lock_irq(&ctx->lock);
1847 if (event->state <= PERF_EVENT_STATE_OFF) {
1848 raw_spin_unlock_irq(&ctx->lock);
1851 raw_spin_unlock_irq(&ctx->lock);
1853 event_function_call(event, __perf_event_disable, NULL);
1856 void perf_event_disable_local(struct perf_event *event)
1858 event_function_local(event, __perf_event_disable, NULL);
1862 * Strictly speaking kernel users cannot create groups and therefore this
1863 * interface does not need the perf_event_ctx_lock() magic.
1865 void perf_event_disable(struct perf_event *event)
1867 struct perf_event_context *ctx;
1869 ctx = perf_event_ctx_lock(event);
1870 _perf_event_disable(event);
1871 perf_event_ctx_unlock(event, ctx);
1873 EXPORT_SYMBOL_GPL(perf_event_disable);
1875 static void perf_set_shadow_time(struct perf_event *event,
1876 struct perf_event_context *ctx,
1880 * use the correct time source for the time snapshot
1882 * We could get by without this by leveraging the
1883 * fact that to get to this function, the caller
1884 * has most likely already called update_context_time()
1885 * and update_cgrp_time_xx() and thus both timestamp
1886 * are identical (or very close). Given that tstamp is,
1887 * already adjusted for cgroup, we could say that:
1888 * tstamp - ctx->timestamp
1890 * tstamp - cgrp->timestamp.
1892 * Then, in perf_output_read(), the calculation would
1893 * work with no changes because:
1894 * - event is guaranteed scheduled in
1895 * - no scheduled out in between
1896 * - thus the timestamp would be the same
1898 * But this is a bit hairy.
1900 * So instead, we have an explicit cgroup call to remain
1901 * within the time time source all along. We believe it
1902 * is cleaner and simpler to understand.
1904 if (is_cgroup_event(event))
1905 perf_cgroup_set_shadow_time(event, tstamp);
1907 event->shadow_ctx_time = tstamp - ctx->timestamp;
1910 #define MAX_INTERRUPTS (~0ULL)
1912 static void perf_log_throttle(struct perf_event *event, int enable);
1913 static void perf_log_itrace_start(struct perf_event *event);
1916 event_sched_in(struct perf_event *event,
1917 struct perf_cpu_context *cpuctx,
1918 struct perf_event_context *ctx)
1920 u64 tstamp = perf_event_time(event);
1923 lockdep_assert_held(&ctx->lock);
1925 if (event->state <= PERF_EVENT_STATE_OFF)
1928 event->state = PERF_EVENT_STATE_ACTIVE;
1929 event->oncpu = smp_processor_id();
1932 * Unthrottle events, since we scheduled we might have missed several
1933 * ticks already, also for a heavily scheduling task there is little
1934 * guarantee it'll get a tick in a timely manner.
1936 if (unlikely(event->hw.interrupts == MAX_INTERRUPTS)) {
1937 perf_log_throttle(event, 1);
1938 event->hw.interrupts = 0;
1942 * The new state must be visible before we turn it on in the hardware:
1946 perf_pmu_disable(event->pmu);
1948 perf_set_shadow_time(event, ctx, tstamp);
1950 perf_log_itrace_start(event);
1952 if (event->pmu->add(event, PERF_EF_START)) {
1953 event->state = PERF_EVENT_STATE_INACTIVE;
1959 event->tstamp_running += tstamp - event->tstamp_stopped;
1961 if (!is_software_event(event))
1962 cpuctx->active_oncpu++;
1963 if (!ctx->nr_active++)
1964 perf_event_ctx_activate(ctx);
1965 if (event->attr.freq && event->attr.sample_freq)
1968 if (event->attr.exclusive)
1969 cpuctx->exclusive = 1;
1972 perf_pmu_enable(event->pmu);
1978 group_sched_in(struct perf_event *group_event,
1979 struct perf_cpu_context *cpuctx,
1980 struct perf_event_context *ctx)
1982 struct perf_event *event, *partial_group = NULL;
1983 struct pmu *pmu = ctx->pmu;
1984 u64 now = ctx->time;
1985 bool simulate = false;
1987 if (group_event->state == PERF_EVENT_STATE_OFF)
1990 pmu->start_txn(pmu, PERF_PMU_TXN_ADD);
1992 if (event_sched_in(group_event, cpuctx, ctx)) {
1993 pmu->cancel_txn(pmu);
1994 perf_mux_hrtimer_restart(cpuctx);
1999 * Schedule in siblings as one group (if any):
2001 list_for_each_entry(event, &group_event->sibling_list, group_entry) {
2002 if (event_sched_in(event, cpuctx, ctx)) {
2003 partial_group = event;
2008 if (!pmu->commit_txn(pmu))
2013 * Groups can be scheduled in as one unit only, so undo any
2014 * partial group before returning:
2015 * The events up to the failed event are scheduled out normally,
2016 * tstamp_stopped will be updated.
2018 * The failed events and the remaining siblings need to have
2019 * their timings updated as if they had gone thru event_sched_in()
2020 * and event_sched_out(). This is required to get consistent timings
2021 * across the group. This also takes care of the case where the group
2022 * could never be scheduled by ensuring tstamp_stopped is set to mark
2023 * the time the event was actually stopped, such that time delta
2024 * calculation in update_event_times() is correct.
2026 list_for_each_entry(event, &group_event->sibling_list, group_entry) {
2027 if (event == partial_group)
2031 event->tstamp_running += now - event->tstamp_stopped;
2032 event->tstamp_stopped = now;
2034 event_sched_out(event, cpuctx, ctx);
2037 event_sched_out(group_event, cpuctx, ctx);
2039 pmu->cancel_txn(pmu);
2041 perf_mux_hrtimer_restart(cpuctx);
2047 * Work out whether we can put this event group on the CPU now.
2049 static int group_can_go_on(struct perf_event *event,
2050 struct perf_cpu_context *cpuctx,
2054 * Groups consisting entirely of software events can always go on.
2056 if (event->group_flags & PERF_GROUP_SOFTWARE)
2059 * If an exclusive group is already on, no other hardware
2062 if (cpuctx->exclusive)
2065 * If this group is exclusive and there are already
2066 * events on the CPU, it can't go on.
2068 if (event->attr.exclusive && cpuctx->active_oncpu)
2071 * Otherwise, try to add it if all previous groups were able
2077 static void add_event_to_ctx(struct perf_event *event,
2078 struct perf_event_context *ctx)
2080 u64 tstamp = perf_event_time(event);
2082 list_add_event(event, ctx);
2083 perf_group_attach(event);
2084 event->tstamp_enabled = tstamp;
2085 event->tstamp_running = tstamp;
2086 event->tstamp_stopped = tstamp;
2089 static void ctx_sched_out(struct perf_event_context *ctx,
2090 struct perf_cpu_context *cpuctx,
2091 enum event_type_t event_type);
2093 ctx_sched_in(struct perf_event_context *ctx,
2094 struct perf_cpu_context *cpuctx,
2095 enum event_type_t event_type,
2096 struct task_struct *task);
2098 static void task_ctx_sched_out(struct perf_cpu_context *cpuctx,
2099 struct perf_event_context *ctx)
2101 if (!cpuctx->task_ctx)
2104 if (WARN_ON_ONCE(ctx != cpuctx->task_ctx))
2107 ctx_sched_out(ctx, cpuctx, EVENT_ALL);
2110 static void perf_event_sched_in(struct perf_cpu_context *cpuctx,
2111 struct perf_event_context *ctx,
2112 struct task_struct *task)
2114 cpu_ctx_sched_in(cpuctx, EVENT_PINNED, task);
2116 ctx_sched_in(ctx, cpuctx, EVENT_PINNED, task);
2117 cpu_ctx_sched_in(cpuctx, EVENT_FLEXIBLE, task);
2119 ctx_sched_in(ctx, cpuctx, EVENT_FLEXIBLE, task);
2122 static void ctx_resched(struct perf_cpu_context *cpuctx,
2123 struct perf_event_context *task_ctx)
2125 perf_pmu_disable(cpuctx->ctx.pmu);
2127 task_ctx_sched_out(cpuctx, task_ctx);
2128 cpu_ctx_sched_out(cpuctx, EVENT_ALL);
2129 perf_event_sched_in(cpuctx, task_ctx, current);
2130 perf_pmu_enable(cpuctx->ctx.pmu);
2134 * Cross CPU call to install and enable a performance event
2136 * Very similar to remote_function() + event_function() but cannot assume that
2137 * things like ctx->is_active and cpuctx->task_ctx are set.
2139 static int __perf_install_in_context(void *info)
2141 struct perf_event *event = info;
2142 struct perf_event_context *ctx = event->ctx;
2143 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
2144 struct perf_event_context *task_ctx = cpuctx->task_ctx;
2145 bool activate = true;
2148 raw_spin_lock(&cpuctx->ctx.lock);
2150 raw_spin_lock(&ctx->lock);
2153 /* If we're on the wrong CPU, try again */
2154 if (task_cpu(ctx->task) != smp_processor_id()) {
2160 * If we're on the right CPU, see if the task we target is
2161 * current, if not we don't have to activate the ctx, a future
2162 * context switch will do that for us.
2164 if (ctx->task != current)
2167 WARN_ON_ONCE(cpuctx->task_ctx && cpuctx->task_ctx != ctx);
2169 } else if (task_ctx) {
2170 raw_spin_lock(&task_ctx->lock);
2174 ctx_sched_out(ctx, cpuctx, EVENT_TIME);
2175 add_event_to_ctx(event, ctx);
2176 ctx_resched(cpuctx, task_ctx);
2178 add_event_to_ctx(event, ctx);
2182 perf_ctx_unlock(cpuctx, task_ctx);
2188 * Attach a performance event to a context.
2190 * Very similar to event_function_call, see comment there.
2193 perf_install_in_context(struct perf_event_context *ctx,
2194 struct perf_event *event,
2197 struct task_struct *task = READ_ONCE(ctx->task);
2199 lockdep_assert_held(&ctx->mutex);
2202 if (event->cpu != -1)
2206 cpu_function_call(cpu, __perf_install_in_context, event);
2211 * Should not happen, we validate the ctx is still alive before calling.
2213 if (WARN_ON_ONCE(task == TASK_TOMBSTONE))
2217 * Installing events is tricky because we cannot rely on ctx->is_active
2218 * to be set in case this is the nr_events 0 -> 1 transition.
2222 * Cannot use task_function_call() because we need to run on the task's
2223 * CPU regardless of whether its current or not.
2225 if (!cpu_function_call(task_cpu(task), __perf_install_in_context, event))
2228 raw_spin_lock_irq(&ctx->lock);
2230 if (WARN_ON_ONCE(task == TASK_TOMBSTONE)) {
2232 * Cannot happen because we already checked above (which also
2233 * cannot happen), and we hold ctx->mutex, which serializes us
2234 * against perf_event_exit_task_context().
2236 raw_spin_unlock_irq(&ctx->lock);
2239 raw_spin_unlock_irq(&ctx->lock);
2241 * Since !ctx->is_active doesn't mean anything, we must IPI
2248 * Put a event into inactive state and update time fields.
2249 * Enabling the leader of a group effectively enables all
2250 * the group members that aren't explicitly disabled, so we
2251 * have to update their ->tstamp_enabled also.
2252 * Note: this works for group members as well as group leaders
2253 * since the non-leader members' sibling_lists will be empty.
2255 static void __perf_event_mark_enabled(struct perf_event *event)
2257 struct perf_event *sub;
2258 u64 tstamp = perf_event_time(event);
2260 event->state = PERF_EVENT_STATE_INACTIVE;
2261 event->tstamp_enabled = tstamp - event->total_time_enabled;
2262 list_for_each_entry(sub, &event->sibling_list, group_entry) {
2263 if (sub->state >= PERF_EVENT_STATE_INACTIVE)
2264 sub->tstamp_enabled = tstamp - sub->total_time_enabled;
2269 * Cross CPU call to enable a performance event
2271 static void __perf_event_enable(struct perf_event *event,
2272 struct perf_cpu_context *cpuctx,
2273 struct perf_event_context *ctx,
2276 struct perf_event *leader = event->group_leader;
2277 struct perf_event_context *task_ctx;
2279 if (event->state >= PERF_EVENT_STATE_INACTIVE ||
2280 event->state <= PERF_EVENT_STATE_ERROR)
2284 ctx_sched_out(ctx, cpuctx, EVENT_TIME);
2286 __perf_event_mark_enabled(event);
2288 if (!ctx->is_active)
2291 if (!event_filter_match(event)) {
2292 if (is_cgroup_event(event))
2293 perf_cgroup_defer_enabled(event);
2294 ctx_sched_in(ctx, cpuctx, EVENT_TIME, current);
2299 * If the event is in a group and isn't the group leader,
2300 * then don't put it on unless the group is on.
2302 if (leader != event && leader->state != PERF_EVENT_STATE_ACTIVE) {
2303 ctx_sched_in(ctx, cpuctx, EVENT_TIME, current);
2307 task_ctx = cpuctx->task_ctx;
2309 WARN_ON_ONCE(task_ctx != ctx);
2311 ctx_resched(cpuctx, task_ctx);
2317 * If event->ctx is a cloned context, callers must make sure that
2318 * every task struct that event->ctx->task could possibly point to
2319 * remains valid. This condition is satisfied when called through
2320 * perf_event_for_each_child or perf_event_for_each as described
2321 * for perf_event_disable.
2323 static void _perf_event_enable(struct perf_event *event)
2325 struct perf_event_context *ctx = event->ctx;
2327 raw_spin_lock_irq(&ctx->lock);
2328 if (event->state >= PERF_EVENT_STATE_INACTIVE ||
2329 event->state < PERF_EVENT_STATE_ERROR) {
2330 raw_spin_unlock_irq(&ctx->lock);
2335 * If the event is in error state, clear that first.
2337 * That way, if we see the event in error state below, we know that it
2338 * has gone back into error state, as distinct from the task having
2339 * been scheduled away before the cross-call arrived.
2341 if (event->state == PERF_EVENT_STATE_ERROR)
2342 event->state = PERF_EVENT_STATE_OFF;
2343 raw_spin_unlock_irq(&ctx->lock);
2345 event_function_call(event, __perf_event_enable, NULL);
2349 * See perf_event_disable();
2351 void perf_event_enable(struct perf_event *event)
2353 struct perf_event_context *ctx;
2355 ctx = perf_event_ctx_lock(event);
2356 _perf_event_enable(event);
2357 perf_event_ctx_unlock(event, ctx);
2359 EXPORT_SYMBOL_GPL(perf_event_enable);
2361 static int _perf_event_refresh(struct perf_event *event, int refresh)
2364 * not supported on inherited events
2366 if (event->attr.inherit || !is_sampling_event(event))
2369 atomic_add(refresh, &event->event_limit);
2370 _perf_event_enable(event);
2376 * See perf_event_disable()
2378 int perf_event_refresh(struct perf_event *event, int refresh)
2380 struct perf_event_context *ctx;
2383 ctx = perf_event_ctx_lock(event);
2384 ret = _perf_event_refresh(event, refresh);
2385 perf_event_ctx_unlock(event, ctx);
2389 EXPORT_SYMBOL_GPL(perf_event_refresh);
2391 static void ctx_sched_out(struct perf_event_context *ctx,
2392 struct perf_cpu_context *cpuctx,
2393 enum event_type_t event_type)
2395 int is_active = ctx->is_active;
2396 struct perf_event *event;
2398 lockdep_assert_held(&ctx->lock);
2400 if (likely(!ctx->nr_events)) {
2402 * See __perf_remove_from_context().
2404 WARN_ON_ONCE(ctx->is_active);
2406 WARN_ON_ONCE(cpuctx->task_ctx);
2410 ctx->is_active &= ~event_type;
2411 if (!(ctx->is_active & EVENT_ALL))
2415 WARN_ON_ONCE(cpuctx->task_ctx != ctx);
2416 if (!ctx->is_active)
2417 cpuctx->task_ctx = NULL;
2420 is_active ^= ctx->is_active; /* changed bits */
2422 if (is_active & EVENT_TIME) {
2423 /* update (and stop) ctx time */
2424 update_context_time(ctx);
2425 update_cgrp_time_from_cpuctx(cpuctx);
2428 if (!ctx->nr_active || !(is_active & EVENT_ALL))
2431 perf_pmu_disable(ctx->pmu);
2432 if (is_active & EVENT_PINNED) {
2433 list_for_each_entry(event, &ctx->pinned_groups, group_entry)
2434 group_sched_out(event, cpuctx, ctx);
2437 if (is_active & EVENT_FLEXIBLE) {
2438 list_for_each_entry(event, &ctx->flexible_groups, group_entry)
2439 group_sched_out(event, cpuctx, ctx);
2441 perf_pmu_enable(ctx->pmu);
2445 * Test whether two contexts are equivalent, i.e. whether they have both been
2446 * cloned from the same version of the same context.
2448 * Equivalence is measured using a generation number in the context that is
2449 * incremented on each modification to it; see unclone_ctx(), list_add_event()
2450 * and list_del_event().
2452 static int context_equiv(struct perf_event_context *ctx1,
2453 struct perf_event_context *ctx2)
2455 lockdep_assert_held(&ctx1->lock);
2456 lockdep_assert_held(&ctx2->lock);
2458 /* Pinning disables the swap optimization */
2459 if (ctx1->pin_count || ctx2->pin_count)
2462 /* If ctx1 is the parent of ctx2 */
2463 if (ctx1 == ctx2->parent_ctx && ctx1->generation == ctx2->parent_gen)
2466 /* If ctx2 is the parent of ctx1 */
2467 if (ctx1->parent_ctx == ctx2 && ctx1->parent_gen == ctx2->generation)
2471 * If ctx1 and ctx2 have the same parent; we flatten the parent
2472 * hierarchy, see perf_event_init_context().
2474 if (ctx1->parent_ctx && ctx1->parent_ctx == ctx2->parent_ctx &&
2475 ctx1->parent_gen == ctx2->parent_gen)
2482 static void __perf_event_sync_stat(struct perf_event *event,
2483 struct perf_event *next_event)
2487 if (!event->attr.inherit_stat)
2491 * Update the event value, we cannot use perf_event_read()
2492 * because we're in the middle of a context switch and have IRQs
2493 * disabled, which upsets smp_call_function_single(), however
2494 * we know the event must be on the current CPU, therefore we
2495 * don't need to use it.
2497 switch (event->state) {
2498 case PERF_EVENT_STATE_ACTIVE:
2499 event->pmu->read(event);
2502 case PERF_EVENT_STATE_INACTIVE:
2503 update_event_times(event);
2511 * In order to keep per-task stats reliable we need to flip the event
2512 * values when we flip the contexts.
2514 value = local64_read(&next_event->count);
2515 value = local64_xchg(&event->count, value);
2516 local64_set(&next_event->count, value);
2518 swap(event->total_time_enabled, next_event->total_time_enabled);
2519 swap(event->total_time_running, next_event->total_time_running);
2522 * Since we swizzled the values, update the user visible data too.
2524 perf_event_update_userpage(event);
2525 perf_event_update_userpage(next_event);
2528 static void perf_event_sync_stat(struct perf_event_context *ctx,
2529 struct perf_event_context *next_ctx)
2531 struct perf_event *event, *next_event;
2536 update_context_time(ctx);
2538 event = list_first_entry(&ctx->event_list,
2539 struct perf_event, event_entry);
2541 next_event = list_first_entry(&next_ctx->event_list,
2542 struct perf_event, event_entry);
2544 while (&event->event_entry != &ctx->event_list &&
2545 &next_event->event_entry != &next_ctx->event_list) {
2547 __perf_event_sync_stat(event, next_event);
2549 event = list_next_entry(event, event_entry);
2550 next_event = list_next_entry(next_event, event_entry);
2554 static void perf_event_context_sched_out(struct task_struct *task, int ctxn,
2555 struct task_struct *next)
2557 struct perf_event_context *ctx = task->perf_event_ctxp[ctxn];
2558 struct perf_event_context *next_ctx;
2559 struct perf_event_context *parent, *next_parent;
2560 struct perf_cpu_context *cpuctx;
2566 cpuctx = __get_cpu_context(ctx);
2567 if (!cpuctx->task_ctx)
2571 next_ctx = next->perf_event_ctxp[ctxn];
2575 parent = rcu_dereference(ctx->parent_ctx);
2576 next_parent = rcu_dereference(next_ctx->parent_ctx);
2578 /* If neither context have a parent context; they cannot be clones. */
2579 if (!parent && !next_parent)
2582 if (next_parent == ctx || next_ctx == parent || next_parent == parent) {
2584 * Looks like the two contexts are clones, so we might be
2585 * able to optimize the context switch. We lock both
2586 * contexts and check that they are clones under the
2587 * lock (including re-checking that neither has been
2588 * uncloned in the meantime). It doesn't matter which
2589 * order we take the locks because no other cpu could
2590 * be trying to lock both of these tasks.
2592 raw_spin_lock(&ctx->lock);
2593 raw_spin_lock_nested(&next_ctx->lock, SINGLE_DEPTH_NESTING);
2594 if (context_equiv(ctx, next_ctx)) {
2595 WRITE_ONCE(ctx->task, next);
2596 WRITE_ONCE(next_ctx->task, task);
2598 swap(ctx->task_ctx_data, next_ctx->task_ctx_data);
2601 * RCU_INIT_POINTER here is safe because we've not
2602 * modified the ctx and the above modification of
2603 * ctx->task and ctx->task_ctx_data are immaterial
2604 * since those values are always verified under
2605 * ctx->lock which we're now holding.
2607 RCU_INIT_POINTER(task->perf_event_ctxp[ctxn], next_ctx);
2608 RCU_INIT_POINTER(next->perf_event_ctxp[ctxn], ctx);
2612 perf_event_sync_stat(ctx, next_ctx);
2614 raw_spin_unlock(&next_ctx->lock);
2615 raw_spin_unlock(&ctx->lock);
2621 raw_spin_lock(&ctx->lock);
2622 task_ctx_sched_out(cpuctx, ctx);
2623 raw_spin_unlock(&ctx->lock);
2627 void perf_sched_cb_dec(struct pmu *pmu)
2629 this_cpu_dec(perf_sched_cb_usages);
2632 void perf_sched_cb_inc(struct pmu *pmu)
2634 this_cpu_inc(perf_sched_cb_usages);
2638 * This function provides the context switch callback to the lower code
2639 * layer. It is invoked ONLY when the context switch callback is enabled.
2641 static void perf_pmu_sched_task(struct task_struct *prev,
2642 struct task_struct *next,
2645 struct perf_cpu_context *cpuctx;
2647 unsigned long flags;
2652 local_irq_save(flags);
2656 list_for_each_entry_rcu(pmu, &pmus, entry) {
2657 if (pmu->sched_task) {
2658 cpuctx = this_cpu_ptr(pmu->pmu_cpu_context);
2660 perf_ctx_lock(cpuctx, cpuctx->task_ctx);
2662 perf_pmu_disable(pmu);
2664 pmu->sched_task(cpuctx->task_ctx, sched_in);
2666 perf_pmu_enable(pmu);
2668 perf_ctx_unlock(cpuctx, cpuctx->task_ctx);
2674 local_irq_restore(flags);
2677 static void perf_event_switch(struct task_struct *task,
2678 struct task_struct *next_prev, bool sched_in);
2680 #define for_each_task_context_nr(ctxn) \
2681 for ((ctxn) = 0; (ctxn) < perf_nr_task_contexts; (ctxn)++)
2684 * Called from scheduler to remove the events of the current task,
2685 * with interrupts disabled.
2687 * We stop each event and update the event value in event->count.
2689 * This does not protect us against NMI, but disable()
2690 * sets the disabled bit in the control field of event _before_
2691 * accessing the event control register. If a NMI hits, then it will
2692 * not restart the event.
2694 void __perf_event_task_sched_out(struct task_struct *task,
2695 struct task_struct *next)
2699 if (__this_cpu_read(perf_sched_cb_usages))
2700 perf_pmu_sched_task(task, next, false);
2702 if (atomic_read(&nr_switch_events))
2703 perf_event_switch(task, next, false);
2705 for_each_task_context_nr(ctxn)
2706 perf_event_context_sched_out(task, ctxn, next);
2709 * if cgroup events exist on this CPU, then we need
2710 * to check if we have to switch out PMU state.
2711 * cgroup event are system-wide mode only
2713 if (atomic_read(this_cpu_ptr(&perf_cgroup_events)))
2714 perf_cgroup_sched_out(task, next);
2718 * Called with IRQs disabled
2720 static void cpu_ctx_sched_out(struct perf_cpu_context *cpuctx,
2721 enum event_type_t event_type)
2723 ctx_sched_out(&cpuctx->ctx, cpuctx, event_type);
2727 ctx_pinned_sched_in(struct perf_event_context *ctx,
2728 struct perf_cpu_context *cpuctx)
2730 struct perf_event *event;
2732 list_for_each_entry(event, &ctx->pinned_groups, group_entry) {
2733 if (event->state <= PERF_EVENT_STATE_OFF)
2735 if (!event_filter_match(event))
2738 /* may need to reset tstamp_enabled */
2739 if (is_cgroup_event(event))
2740 perf_cgroup_mark_enabled(event, ctx);
2742 if (group_can_go_on(event, cpuctx, 1))
2743 group_sched_in(event, cpuctx, ctx);
2746 * If this pinned group hasn't been scheduled,
2747 * put it in error state.
2749 if (event->state == PERF_EVENT_STATE_INACTIVE) {
2750 update_group_times(event);
2751 event->state = PERF_EVENT_STATE_ERROR;
2757 ctx_flexible_sched_in(struct perf_event_context *ctx,
2758 struct perf_cpu_context *cpuctx)
2760 struct perf_event *event;
2763 list_for_each_entry(event, &ctx->flexible_groups, group_entry) {
2764 /* Ignore events in OFF or ERROR state */
2765 if (event->state <= PERF_EVENT_STATE_OFF)
2768 * Listen to the 'cpu' scheduling filter constraint
2771 if (!event_filter_match(event))
2774 /* may need to reset tstamp_enabled */
2775 if (is_cgroup_event(event))
2776 perf_cgroup_mark_enabled(event, ctx);
2778 if (group_can_go_on(event, cpuctx, can_add_hw)) {
2779 if (group_sched_in(event, cpuctx, ctx))
2786 ctx_sched_in(struct perf_event_context *ctx,
2787 struct perf_cpu_context *cpuctx,
2788 enum event_type_t event_type,
2789 struct task_struct *task)
2791 int is_active = ctx->is_active;
2794 lockdep_assert_held(&ctx->lock);
2796 if (likely(!ctx->nr_events))
2799 ctx->is_active |= (event_type | EVENT_TIME);
2802 cpuctx->task_ctx = ctx;
2804 WARN_ON_ONCE(cpuctx->task_ctx != ctx);
2807 is_active ^= ctx->is_active; /* changed bits */
2809 if (is_active & EVENT_TIME) {
2810 /* start ctx time */
2812 ctx->timestamp = now;
2813 perf_cgroup_set_timestamp(task, ctx);
2817 * First go through the list and put on any pinned groups
2818 * in order to give them the best chance of going on.
2820 if (is_active & EVENT_PINNED)
2821 ctx_pinned_sched_in(ctx, cpuctx);
2823 /* Then walk through the lower prio flexible groups */
2824 if (is_active & EVENT_FLEXIBLE)
2825 ctx_flexible_sched_in(ctx, cpuctx);
2828 static void cpu_ctx_sched_in(struct perf_cpu_context *cpuctx,
2829 enum event_type_t event_type,
2830 struct task_struct *task)
2832 struct perf_event_context *ctx = &cpuctx->ctx;
2834 ctx_sched_in(ctx, cpuctx, event_type, task);
2837 static void perf_event_context_sched_in(struct perf_event_context *ctx,
2838 struct task_struct *task)
2840 struct perf_cpu_context *cpuctx;
2842 cpuctx = __get_cpu_context(ctx);
2843 if (cpuctx->task_ctx == ctx)
2846 perf_ctx_lock(cpuctx, ctx);
2847 perf_pmu_disable(ctx->pmu);
2849 * We want to keep the following priority order:
2850 * cpu pinned (that don't need to move), task pinned,
2851 * cpu flexible, task flexible.
2853 cpu_ctx_sched_out(cpuctx, EVENT_FLEXIBLE);
2854 perf_event_sched_in(cpuctx, ctx, task);
2855 perf_pmu_enable(ctx->pmu);
2856 perf_ctx_unlock(cpuctx, ctx);
2860 * Called from scheduler to add the events of the current task
2861 * with interrupts disabled.
2863 * We restore the event value and then enable it.
2865 * This does not protect us against NMI, but enable()
2866 * sets the enabled bit in the control field of event _before_
2867 * accessing the event control register. If a NMI hits, then it will
2868 * keep the event running.
2870 void __perf_event_task_sched_in(struct task_struct *prev,
2871 struct task_struct *task)
2873 struct perf_event_context *ctx;
2877 * If cgroup events exist on this CPU, then we need to check if we have
2878 * to switch in PMU state; cgroup event are system-wide mode only.
2880 * Since cgroup events are CPU events, we must schedule these in before
2881 * we schedule in the task events.
2883 if (atomic_read(this_cpu_ptr(&perf_cgroup_events)))
2884 perf_cgroup_sched_in(prev, task);
2886 for_each_task_context_nr(ctxn) {
2887 ctx = task->perf_event_ctxp[ctxn];
2891 perf_event_context_sched_in(ctx, task);
2894 if (atomic_read(&nr_switch_events))
2895 perf_event_switch(task, prev, true);
2897 if (__this_cpu_read(perf_sched_cb_usages))
2898 perf_pmu_sched_task(prev, task, true);
2901 static u64 perf_calculate_period(struct perf_event *event, u64 nsec, u64 count)
2903 u64 frequency = event->attr.sample_freq;
2904 u64 sec = NSEC_PER_SEC;
2905 u64 divisor, dividend;
2907 int count_fls, nsec_fls, frequency_fls, sec_fls;
2909 count_fls = fls64(count);
2910 nsec_fls = fls64(nsec);
2911 frequency_fls = fls64(frequency);
2915 * We got @count in @nsec, with a target of sample_freq HZ
2916 * the target period becomes:
2919 * period = -------------------
2920 * @nsec * sample_freq
2925 * Reduce accuracy by one bit such that @a and @b converge
2926 * to a similar magnitude.
2928 #define REDUCE_FLS(a, b) \
2930 if (a##_fls > b##_fls) { \
2940 * Reduce accuracy until either term fits in a u64, then proceed with
2941 * the other, so that finally we can do a u64/u64 division.
2943 while (count_fls + sec_fls > 64 && nsec_fls + frequency_fls > 64) {
2944 REDUCE_FLS(nsec, frequency);
2945 REDUCE_FLS(sec, count);
2948 if (count_fls + sec_fls > 64) {
2949 divisor = nsec * frequency;
2951 while (count_fls + sec_fls > 64) {
2952 REDUCE_FLS(count, sec);
2956 dividend = count * sec;
2958 dividend = count * sec;
2960 while (nsec_fls + frequency_fls > 64) {
2961 REDUCE_FLS(nsec, frequency);
2965 divisor = nsec * frequency;
2971 return div64_u64(dividend, divisor);
2974 static DEFINE_PER_CPU(int, perf_throttled_count);
2975 static DEFINE_PER_CPU(u64, perf_throttled_seq);
2977 static void perf_adjust_period(struct perf_event *event, u64 nsec, u64 count, bool disable)
2979 struct hw_perf_event *hwc = &event->hw;
2980 s64 period, sample_period;
2983 period = perf_calculate_period(event, nsec, count);
2985 delta = (s64)(period - hwc->sample_period);
2986 delta = (delta + 7) / 8; /* low pass filter */
2988 sample_period = hwc->sample_period + delta;
2993 hwc->sample_period = sample_period;
2995 if (local64_read(&hwc->period_left) > 8*sample_period) {
2997 event->pmu->stop(event, PERF_EF_UPDATE);
2999 local64_set(&hwc->period_left, 0);
3002 event->pmu->start(event, PERF_EF_RELOAD);
3007 * combine freq adjustment with unthrottling to avoid two passes over the
3008 * events. At the same time, make sure, having freq events does not change
3009 * the rate of unthrottling as that would introduce bias.
3011 static void perf_adjust_freq_unthr_context(struct perf_event_context *ctx,
3014 struct perf_event *event;
3015 struct hw_perf_event *hwc;
3016 u64 now, period = TICK_NSEC;
3020 * only need to iterate over all events iff:
3021 * - context have events in frequency mode (needs freq adjust)
3022 * - there are events to unthrottle on this cpu
3024 if (!(ctx->nr_freq || needs_unthr))
3027 raw_spin_lock(&ctx->lock);
3028 perf_pmu_disable(ctx->pmu);
3030 list_for_each_entry_rcu(event, &ctx->event_list, event_entry) {
3031 if (event->state != PERF_EVENT_STATE_ACTIVE)
3034 if (!event_filter_match(event))
3037 perf_pmu_disable(event->pmu);
3041 if (hwc->interrupts == MAX_INTERRUPTS) {
3042 hwc->interrupts = 0;
3043 perf_log_throttle(event, 1);
3044 event->pmu->start(event, 0);
3047 if (!event->attr.freq || !event->attr.sample_freq)
3051 * stop the event and update event->count
3053 event->pmu->stop(event, PERF_EF_UPDATE);
3055 now = local64_read(&event->count);
3056 delta = now - hwc->freq_count_stamp;
3057 hwc->freq_count_stamp = now;
3061 * reload only if value has changed
3062 * we have stopped the event so tell that
3063 * to perf_adjust_period() to avoid stopping it
3067 perf_adjust_period(event, period, delta, false);
3069 event->pmu->start(event, delta > 0 ? PERF_EF_RELOAD : 0);
3071 perf_pmu_enable(event->pmu);
3074 perf_pmu_enable(ctx->pmu);
3075 raw_spin_unlock(&ctx->lock);
3079 * Round-robin a context's events:
3081 static void rotate_ctx(struct perf_event_context *ctx)
3084 * Rotate the first entry last of non-pinned groups. Rotation might be
3085 * disabled by the inheritance code.
3087 if (!ctx->rotate_disable)
3088 list_rotate_left(&ctx->flexible_groups);
3091 static int perf_rotate_context(struct perf_cpu_context *cpuctx)
3093 struct perf_event_context *ctx = NULL;
3096 if (cpuctx->ctx.nr_events) {
3097 if (cpuctx->ctx.nr_events != cpuctx->ctx.nr_active)
3101 ctx = cpuctx->task_ctx;
3102 if (ctx && ctx->nr_events) {
3103 if (ctx->nr_events != ctx->nr_active)
3110 perf_ctx_lock(cpuctx, cpuctx->task_ctx);
3111 perf_pmu_disable(cpuctx->ctx.pmu);
3113 cpu_ctx_sched_out(cpuctx, EVENT_FLEXIBLE);
3115 ctx_sched_out(ctx, cpuctx, EVENT_FLEXIBLE);
3117 rotate_ctx(&cpuctx->ctx);
3121 perf_event_sched_in(cpuctx, ctx, current);
3123 perf_pmu_enable(cpuctx->ctx.pmu);
3124 perf_ctx_unlock(cpuctx, cpuctx->task_ctx);
3130 void perf_event_task_tick(void)
3132 struct list_head *head = this_cpu_ptr(&active_ctx_list);
3133 struct perf_event_context *ctx, *tmp;
3136 WARN_ON(!irqs_disabled());
3138 __this_cpu_inc(perf_throttled_seq);
3139 throttled = __this_cpu_xchg(perf_throttled_count, 0);
3140 tick_dep_clear_cpu(smp_processor_id(), TICK_DEP_BIT_PERF_EVENTS);
3142 list_for_each_entry_safe(ctx, tmp, head, active_ctx_list)
3143 perf_adjust_freq_unthr_context(ctx, throttled);
3146 static int event_enable_on_exec(struct perf_event *event,
3147 struct perf_event_context *ctx)
3149 if (!event->attr.enable_on_exec)
3152 event->attr.enable_on_exec = 0;
3153 if (event->state >= PERF_EVENT_STATE_INACTIVE)
3156 __perf_event_mark_enabled(event);
3162 * Enable all of a task's events that have been marked enable-on-exec.
3163 * This expects task == current.
3165 static void perf_event_enable_on_exec(int ctxn)
3167 struct perf_event_context *ctx, *clone_ctx = NULL;
3168 struct perf_cpu_context *cpuctx;
3169 struct perf_event *event;
3170 unsigned long flags;
3173 local_irq_save(flags);
3174 ctx = current->perf_event_ctxp[ctxn];
3175 if (!ctx || !ctx->nr_events)
3178 cpuctx = __get_cpu_context(ctx);
3179 perf_ctx_lock(cpuctx, ctx);
3180 ctx_sched_out(ctx, cpuctx, EVENT_TIME);
3181 list_for_each_entry(event, &ctx->event_list, event_entry)
3182 enabled |= event_enable_on_exec(event, ctx);
3185 * Unclone and reschedule this context if we enabled any event.
3188 clone_ctx = unclone_ctx(ctx);
3189 ctx_resched(cpuctx, ctx);
3191 perf_ctx_unlock(cpuctx, ctx);
3194 local_irq_restore(flags);
3200 void perf_event_exec(void)
3205 for_each_task_context_nr(ctxn)
3206 perf_event_enable_on_exec(ctxn);
3210 struct perf_read_data {
3211 struct perf_event *event;
3217 * Cross CPU call to read the hardware event
3219 static void __perf_event_read(void *info)
3221 struct perf_read_data *data = info;
3222 struct perf_event *sub, *event = data->event;
3223 struct perf_event_context *ctx = event->ctx;
3224 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
3225 struct pmu *pmu = event->pmu;
3228 * If this is a task context, we need to check whether it is
3229 * the current task context of this cpu. If not it has been
3230 * scheduled out before the smp call arrived. In that case
3231 * event->count would have been updated to a recent sample
3232 * when the event was scheduled out.
3234 if (ctx->task && cpuctx->task_ctx != ctx)
3237 raw_spin_lock(&ctx->lock);
3238 if (ctx->is_active) {
3239 update_context_time(ctx);
3240 update_cgrp_time_from_event(event);
3243 update_event_times(event);
3244 if (event->state != PERF_EVENT_STATE_ACTIVE)
3253 pmu->start_txn(pmu, PERF_PMU_TXN_READ);
3257 list_for_each_entry(sub, &event->sibling_list, group_entry) {
3258 update_event_times(sub);
3259 if (sub->state == PERF_EVENT_STATE_ACTIVE) {
3261 * Use sibling's PMU rather than @event's since
3262 * sibling could be on different (eg: software) PMU.
3264 sub->pmu->read(sub);
3268 data->ret = pmu->commit_txn(pmu);
3271 raw_spin_unlock(&ctx->lock);
3274 static inline u64 perf_event_count(struct perf_event *event)
3276 if (event->pmu->count)
3277 return event->pmu->count(event);
3279 return __perf_event_count(event);
3283 * NMI-safe method to read a local event, that is an event that
3285 * - either for the current task, or for this CPU
3286 * - does not have inherit set, for inherited task events
3287 * will not be local and we cannot read them atomically
3288 * - must not have a pmu::count method
3290 u64 perf_event_read_local(struct perf_event *event)
3292 unsigned long flags;
3296 * Disabling interrupts avoids all counter scheduling (context
3297 * switches, timer based rotation and IPIs).
3299 local_irq_save(flags);
3301 /* If this is a per-task event, it must be for current */
3302 WARN_ON_ONCE((event->attach_state & PERF_ATTACH_TASK) &&
3303 event->hw.target != current);
3305 /* If this is a per-CPU event, it must be for this CPU */
3306 WARN_ON_ONCE(!(event->attach_state & PERF_ATTACH_TASK) &&
3307 event->cpu != smp_processor_id());
3310 * It must not be an event with inherit set, we cannot read
3311 * all child counters from atomic context.
3313 WARN_ON_ONCE(event->attr.inherit);
3316 * It must not have a pmu::count method, those are not
3319 WARN_ON_ONCE(event->pmu->count);
3322 * If the event is currently on this CPU, its either a per-task event,
3323 * or local to this CPU. Furthermore it means its ACTIVE (otherwise
3326 if (event->oncpu == smp_processor_id())
3327 event->pmu->read(event);
3329 val = local64_read(&event->count);
3330 local_irq_restore(flags);
3335 static int perf_event_read(struct perf_event *event, bool group)
3340 * If event is enabled and currently active on a CPU, update the
3341 * value in the event structure:
3343 if (event->state == PERF_EVENT_STATE_ACTIVE) {
3344 struct perf_read_data data = {
3349 smp_call_function_single(event->oncpu,
3350 __perf_event_read, &data, 1);
3352 } else if (event->state == PERF_EVENT_STATE_INACTIVE) {
3353 struct perf_event_context *ctx = event->ctx;
3354 unsigned long flags;
3356 raw_spin_lock_irqsave(&ctx->lock, flags);
3358 * may read while context is not active
3359 * (e.g., thread is blocked), in that case
3360 * we cannot update context time
3362 if (ctx->is_active) {
3363 update_context_time(ctx);
3364 update_cgrp_time_from_event(event);
3367 update_group_times(event);
3369 update_event_times(event);
3370 raw_spin_unlock_irqrestore(&ctx->lock, flags);
3377 * Initialize the perf_event context in a task_struct:
3379 static void __perf_event_init_context(struct perf_event_context *ctx)
3381 raw_spin_lock_init(&ctx->lock);
3382 mutex_init(&ctx->mutex);
3383 INIT_LIST_HEAD(&ctx->active_ctx_list);
3384 INIT_LIST_HEAD(&ctx->pinned_groups);
3385 INIT_LIST_HEAD(&ctx->flexible_groups);
3386 INIT_LIST_HEAD(&ctx->event_list);
3387 atomic_set(&ctx->refcount, 1);
3390 static struct perf_event_context *
3391 alloc_perf_context(struct pmu *pmu, struct task_struct *task)
3393 struct perf_event_context *ctx;
3395 ctx = kzalloc(sizeof(struct perf_event_context), GFP_KERNEL);
3399 __perf_event_init_context(ctx);
3402 get_task_struct(task);
3409 static struct task_struct *
3410 find_lively_task_by_vpid(pid_t vpid)
3412 struct task_struct *task;
3419 task = find_task_by_vpid(vpid);
3421 get_task_struct(task);
3425 return ERR_PTR(-ESRCH);
3427 /* Reuse ptrace permission checks for now. */
3429 if (!ptrace_may_access(task, PTRACE_MODE_READ_REALCREDS))
3434 put_task_struct(task);
3435 return ERR_PTR(err);
3440 * Returns a matching context with refcount and pincount.
3442 static struct perf_event_context *
3443 find_get_context(struct pmu *pmu, struct task_struct *task,
3444 struct perf_event *event)
3446 struct perf_event_context *ctx, *clone_ctx = NULL;
3447 struct perf_cpu_context *cpuctx;
3448 void *task_ctx_data = NULL;
3449 unsigned long flags;
3451 int cpu = event->cpu;
3454 /* Must be root to operate on a CPU event: */
3455 if (perf_paranoid_cpu() && !capable(CAP_SYS_ADMIN))
3456 return ERR_PTR(-EACCES);
3459 * We could be clever and allow to attach a event to an
3460 * offline CPU and activate it when the CPU comes up, but
3463 if (!cpu_online(cpu))
3464 return ERR_PTR(-ENODEV);
3466 cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
3475 ctxn = pmu->task_ctx_nr;
3479 if (event->attach_state & PERF_ATTACH_TASK_DATA) {
3480 task_ctx_data = kzalloc(pmu->task_ctx_size, GFP_KERNEL);
3481 if (!task_ctx_data) {
3488 ctx = perf_lock_task_context(task, ctxn, &flags);
3490 clone_ctx = unclone_ctx(ctx);
3493 if (task_ctx_data && !ctx->task_ctx_data) {
3494 ctx->task_ctx_data = task_ctx_data;
3495 task_ctx_data = NULL;
3497 raw_spin_unlock_irqrestore(&ctx->lock, flags);
3502 ctx = alloc_perf_context(pmu, task);
3507 if (task_ctx_data) {
3508 ctx->task_ctx_data = task_ctx_data;
3509 task_ctx_data = NULL;
3513 mutex_lock(&task->perf_event_mutex);
3515 * If it has already passed perf_event_exit_task().
3516 * we must see PF_EXITING, it takes this mutex too.
3518 if (task->flags & PF_EXITING)
3520 else if (task->perf_event_ctxp[ctxn])
3525 rcu_assign_pointer(task->perf_event_ctxp[ctxn], ctx);
3527 mutex_unlock(&task->perf_event_mutex);
3529 if (unlikely(err)) {
3538 kfree(task_ctx_data);
3542 kfree(task_ctx_data);
3543 return ERR_PTR(err);
3546 static void perf_event_free_filter(struct perf_event *event);
3547 static void perf_event_free_bpf_prog(struct perf_event *event);
3549 static void free_event_rcu(struct rcu_head *head)
3551 struct perf_event *event;
3553 event = container_of(head, struct perf_event, rcu_head);
3555 put_pid_ns(event->ns);
3556 perf_event_free_filter(event);
3560 static void ring_buffer_attach(struct perf_event *event,
3561 struct ring_buffer *rb);
3563 static void unaccount_event_cpu(struct perf_event *event, int cpu)
3568 if (is_cgroup_event(event))
3569 atomic_dec(&per_cpu(perf_cgroup_events, cpu));
3572 #ifdef CONFIG_NO_HZ_FULL
3573 static DEFINE_SPINLOCK(nr_freq_lock);
3576 static void unaccount_freq_event_nohz(void)
3578 #ifdef CONFIG_NO_HZ_FULL
3579 spin_lock(&nr_freq_lock);
3580 if (atomic_dec_and_test(&nr_freq_events))
3581 tick_nohz_dep_clear(TICK_DEP_BIT_PERF_EVENTS);
3582 spin_unlock(&nr_freq_lock);
3586 static void unaccount_freq_event(void)
3588 if (tick_nohz_full_enabled())
3589 unaccount_freq_event_nohz();
3591 atomic_dec(&nr_freq_events);
3594 static void unaccount_event(struct perf_event *event)
3601 if (event->attach_state & PERF_ATTACH_TASK)
3603 if (event->attr.mmap || event->attr.mmap_data)
3604 atomic_dec(&nr_mmap_events);
3605 if (event->attr.comm)
3606 atomic_dec(&nr_comm_events);
3607 if (event->attr.task)
3608 atomic_dec(&nr_task_events);
3609 if (event->attr.freq)
3610 unaccount_freq_event();
3611 if (event->attr.context_switch) {
3613 atomic_dec(&nr_switch_events);
3615 if (is_cgroup_event(event))
3617 if (has_branch_stack(event))
3621 if (!atomic_add_unless(&perf_sched_count, -1, 1))
3622 schedule_delayed_work(&perf_sched_work, HZ);
3625 unaccount_event_cpu(event, event->cpu);
3628 static void perf_sched_delayed(struct work_struct *work)
3630 mutex_lock(&perf_sched_mutex);
3631 if (atomic_dec_and_test(&perf_sched_count))
3632 static_branch_disable(&perf_sched_events);
3633 mutex_unlock(&perf_sched_mutex);
3637 * The following implement mutual exclusion of events on "exclusive" pmus
3638 * (PERF_PMU_CAP_EXCLUSIVE). Such pmus can only have one event scheduled
3639 * at a time, so we disallow creating events that might conflict, namely:
3641 * 1) cpu-wide events in the presence of per-task events,
3642 * 2) per-task events in the presence of cpu-wide events,
3643 * 3) two matching events on the same context.
3645 * The former two cases are handled in the allocation path (perf_event_alloc(),
3646 * _free_event()), the latter -- before the first perf_install_in_context().
3648 static int exclusive_event_init(struct perf_event *event)
3650 struct pmu *pmu = event->pmu;
3652 if (!(pmu->capabilities & PERF_PMU_CAP_EXCLUSIVE))
3656 * Prevent co-existence of per-task and cpu-wide events on the
3657 * same exclusive pmu.
3659 * Negative pmu::exclusive_cnt means there are cpu-wide
3660 * events on this "exclusive" pmu, positive means there are
3663 * Since this is called in perf_event_alloc() path, event::ctx
3664 * doesn't exist yet; it is, however, safe to use PERF_ATTACH_TASK
3665 * to mean "per-task event", because unlike other attach states it
3666 * never gets cleared.
3668 if (event->attach_state & PERF_ATTACH_TASK) {
3669 if (!atomic_inc_unless_negative(&pmu->exclusive_cnt))
3672 if (!atomic_dec_unless_positive(&pmu->exclusive_cnt))
3679 static void exclusive_event_destroy(struct perf_event *event)
3681 struct pmu *pmu = event->pmu;
3683 if (!(pmu->capabilities & PERF_PMU_CAP_EXCLUSIVE))
3686 /* see comment in exclusive_event_init() */
3687 if (event->attach_state & PERF_ATTACH_TASK)
3688 atomic_dec(&pmu->exclusive_cnt);
3690 atomic_inc(&pmu->exclusive_cnt);
3693 static bool exclusive_event_match(struct perf_event *e1, struct perf_event *e2)
3695 if ((e1->pmu->capabilities & PERF_PMU_CAP_EXCLUSIVE) &&
3696 (e1->cpu == e2->cpu ||
3703 /* Called under the same ctx::mutex as perf_install_in_context() */
3704 static bool exclusive_event_installable(struct perf_event *event,
3705 struct perf_event_context *ctx)
3707 struct perf_event *iter_event;
3708 struct pmu *pmu = event->pmu;
3710 if (!(pmu->capabilities & PERF_PMU_CAP_EXCLUSIVE))
3713 list_for_each_entry(iter_event, &ctx->event_list, event_entry) {
3714 if (exclusive_event_match(iter_event, event))
3721 static void _free_event(struct perf_event *event)
3723 irq_work_sync(&event->pending);
3725 unaccount_event(event);
3729 * Can happen when we close an event with re-directed output.
3731 * Since we have a 0 refcount, perf_mmap_close() will skip
3732 * over us; possibly making our ring_buffer_put() the last.
3734 mutex_lock(&event->mmap_mutex);
3735 ring_buffer_attach(event, NULL);
3736 mutex_unlock(&event->mmap_mutex);
3739 if (is_cgroup_event(event))
3740 perf_detach_cgroup(event);
3742 if (!event->parent) {
3743 if (event->attr.sample_type & PERF_SAMPLE_CALLCHAIN)
3744 put_callchain_buffers();
3747 perf_event_free_bpf_prog(event);
3750 event->destroy(event);
3753 put_ctx(event->ctx);
3756 exclusive_event_destroy(event);
3757 module_put(event->pmu->module);
3760 call_rcu(&event->rcu_head, free_event_rcu);
3764 * Used to free events which have a known refcount of 1, such as in error paths
3765 * where the event isn't exposed yet and inherited events.
3767 static void free_event(struct perf_event *event)
3769 if (WARN(atomic_long_cmpxchg(&event->refcount, 1, 0) != 1,
3770 "unexpected event refcount: %ld; ptr=%p\n",
3771 atomic_long_read(&event->refcount), event)) {
3772 /* leak to avoid use-after-free */
3780 * Remove user event from the owner task.
3782 static void perf_remove_from_owner(struct perf_event *event)
3784 struct task_struct *owner;
3788 * Matches the smp_store_release() in perf_event_exit_task(). If we
3789 * observe !owner it means the list deletion is complete and we can
3790 * indeed free this event, otherwise we need to serialize on
3791 * owner->perf_event_mutex.
3793 owner = lockless_dereference(event->owner);
3796 * Since delayed_put_task_struct() also drops the last
3797 * task reference we can safely take a new reference
3798 * while holding the rcu_read_lock().
3800 get_task_struct(owner);
3806 * If we're here through perf_event_exit_task() we're already
3807 * holding ctx->mutex which would be an inversion wrt. the
3808 * normal lock order.
3810 * However we can safely take this lock because its the child
3813 mutex_lock_nested(&owner->perf_event_mutex, SINGLE_DEPTH_NESTING);
3816 * We have to re-check the event->owner field, if it is cleared
3817 * we raced with perf_event_exit_task(), acquiring the mutex
3818 * ensured they're done, and we can proceed with freeing the
3822 list_del_init(&event->owner_entry);
3823 smp_store_release(&event->owner, NULL);
3825 mutex_unlock(&owner->perf_event_mutex);
3826 put_task_struct(owner);
3830 static void put_event(struct perf_event *event)
3832 if (!atomic_long_dec_and_test(&event->refcount))
3839 * Kill an event dead; while event:refcount will preserve the event
3840 * object, it will not preserve its functionality. Once the last 'user'
3841 * gives up the object, we'll destroy the thing.
3843 int perf_event_release_kernel(struct perf_event *event)
3845 struct perf_event_context *ctx = event->ctx;
3846 struct perf_event *child, *tmp;
3849 * If we got here through err_file: fput(event_file); we will not have
3850 * attached to a context yet.
3853 WARN_ON_ONCE(event->attach_state &
3854 (PERF_ATTACH_CONTEXT|PERF_ATTACH_GROUP));
3858 if (!is_kernel_event(event))
3859 perf_remove_from_owner(event);
3861 ctx = perf_event_ctx_lock(event);
3862 WARN_ON_ONCE(ctx->parent_ctx);
3863 perf_remove_from_context(event, DETACH_GROUP);
3865 raw_spin_lock_irq(&ctx->lock);
3867 * Mark this even as STATE_DEAD, there is no external reference to it
3870 * Anybody acquiring event->child_mutex after the below loop _must_
3871 * also see this, most importantly inherit_event() which will avoid
3872 * placing more children on the list.
3874 * Thus this guarantees that we will in fact observe and kill _ALL_
3877 event->state = PERF_EVENT_STATE_DEAD;
3878 raw_spin_unlock_irq(&ctx->lock);
3880 perf_event_ctx_unlock(event, ctx);
3883 mutex_lock(&event->child_mutex);
3884 list_for_each_entry(child, &event->child_list, child_list) {
3887 * Cannot change, child events are not migrated, see the
3888 * comment with perf_event_ctx_lock_nested().
3890 ctx = lockless_dereference(child->ctx);
3892 * Since child_mutex nests inside ctx::mutex, we must jump
3893 * through hoops. We start by grabbing a reference on the ctx.
3895 * Since the event cannot get freed while we hold the
3896 * child_mutex, the context must also exist and have a !0
3902 * Now that we have a ctx ref, we can drop child_mutex, and
3903 * acquire ctx::mutex without fear of it going away. Then we
3904 * can re-acquire child_mutex.
3906 mutex_unlock(&event->child_mutex);
3907 mutex_lock(&ctx->mutex);
3908 mutex_lock(&event->child_mutex);
3911 * Now that we hold ctx::mutex and child_mutex, revalidate our
3912 * state, if child is still the first entry, it didn't get freed
3913 * and we can continue doing so.
3915 tmp = list_first_entry_or_null(&event->child_list,
3916 struct perf_event, child_list);
3918 perf_remove_from_context(child, DETACH_GROUP);
3919 list_del(&child->child_list);
3922 * This matches the refcount bump in inherit_event();
3923 * this can't be the last reference.
3928 mutex_unlock(&event->child_mutex);
3929 mutex_unlock(&ctx->mutex);
3933 mutex_unlock(&event->child_mutex);
3936 put_event(event); /* Must be the 'last' reference */
3939 EXPORT_SYMBOL_GPL(perf_event_release_kernel);
3942 * Called when the last reference to the file is gone.
3944 static int perf_release(struct inode *inode, struct file *file)
3946 perf_event_release_kernel(file->private_data);
3950 u64 perf_event_read_value(struct perf_event *event, u64 *enabled, u64 *running)
3952 struct perf_event *child;
3958 mutex_lock(&event->child_mutex);
3960 (void)perf_event_read(event, false);
3961 total += perf_event_count(event);
3963 *enabled += event->total_time_enabled +
3964 atomic64_read(&event->child_total_time_enabled);
3965 *running += event->total_time_running +
3966 atomic64_read(&event->child_total_time_running);
3968 list_for_each_entry(child, &event->child_list, child_list) {
3969 (void)perf_event_read(child, false);
3970 total += perf_event_count(child);
3971 *enabled += child->total_time_enabled;
3972 *running += child->total_time_running;
3974 mutex_unlock(&event->child_mutex);
3978 EXPORT_SYMBOL_GPL(perf_event_read_value);
3980 static int __perf_read_group_add(struct perf_event *leader,
3981 u64 read_format, u64 *values)
3983 struct perf_event *sub;
3984 int n = 1; /* skip @nr */
3987 ret = perf_event_read(leader, true);
3992 * Since we co-schedule groups, {enabled,running} times of siblings
3993 * will be identical to those of the leader, so we only publish one
3996 if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED) {
3997 values[n++] += leader->total_time_enabled +
3998 atomic64_read(&leader->child_total_time_enabled);
4001 if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING) {
4002 values[n++] += leader->total_time_running +
4003 atomic64_read(&leader->child_total_time_running);
4007 * Write {count,id} tuples for every sibling.
4009 values[n++] += perf_event_count(leader);
4010 if (read_format & PERF_FORMAT_ID)
4011 values[n++] = primary_event_id(leader);
4013 list_for_each_entry(sub, &leader->sibling_list, group_entry) {
4014 values[n++] += perf_event_count(sub);
4015 if (read_format & PERF_FORMAT_ID)
4016 values[n++] = primary_event_id(sub);
4022 static int perf_read_group(struct perf_event *event,
4023 u64 read_format, char __user *buf)
4025 struct perf_event *leader = event->group_leader, *child;
4026 struct perf_event_context *ctx = leader->ctx;
4030 lockdep_assert_held(&ctx->mutex);
4032 values = kzalloc(event->read_size, GFP_KERNEL);
4036 values[0] = 1 + leader->nr_siblings;
4039 * By locking the child_mutex of the leader we effectively
4040 * lock the child list of all siblings.. XXX explain how.
4042 mutex_lock(&leader->child_mutex);
4044 ret = __perf_read_group_add(leader, read_format, values);
4048 list_for_each_entry(child, &leader->child_list, child_list) {
4049 ret = __perf_read_group_add(child, read_format, values);
4054 mutex_unlock(&leader->child_mutex);
4056 ret = event->read_size;
4057 if (copy_to_user(buf, values, event->read_size))
4062 mutex_unlock(&leader->child_mutex);
4068 static int perf_read_one(struct perf_event *event,
4069 u64 read_format, char __user *buf)
4071 u64 enabled, running;
4075 values[n++] = perf_event_read_value(event, &enabled, &running);
4076 if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED)
4077 values[n++] = enabled;
4078 if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING)
4079 values[n++] = running;
4080 if (read_format & PERF_FORMAT_ID)
4081 values[n++] = primary_event_id(event);
4083 if (copy_to_user(buf, values, n * sizeof(u64)))
4086 return n * sizeof(u64);
4089 static bool is_event_hup(struct perf_event *event)
4093 if (event->state > PERF_EVENT_STATE_EXIT)
4096 mutex_lock(&event->child_mutex);
4097 no_children = list_empty(&event->child_list);
4098 mutex_unlock(&event->child_mutex);
4103 * Read the performance event - simple non blocking version for now
4106 __perf_read(struct perf_event *event, char __user *buf, size_t count)
4108 u64 read_format = event->attr.read_format;
4112 * Return end-of-file for a read on a event that is in
4113 * error state (i.e. because it was pinned but it couldn't be
4114 * scheduled on to the CPU at some point).
4116 if (event->state == PERF_EVENT_STATE_ERROR)
4119 if (count < event->read_size)
4122 WARN_ON_ONCE(event->ctx->parent_ctx);
4123 if (read_format & PERF_FORMAT_GROUP)
4124 ret = perf_read_group(event, read_format, buf);
4126 ret = perf_read_one(event, read_format, buf);
4132 perf_read(struct file *file, char __user *buf, size_t count, loff_t *ppos)
4134 struct perf_event *event = file->private_data;
4135 struct perf_event_context *ctx;
4138 ctx = perf_event_ctx_lock(event);
4139 ret = __perf_read(event, buf, count);
4140 perf_event_ctx_unlock(event, ctx);
4145 static unsigned int perf_poll(struct file *file, poll_table *wait)
4147 struct perf_event *event = file->private_data;
4148 struct ring_buffer *rb;
4149 unsigned int events = POLLHUP;
4151 poll_wait(file, &event->waitq, wait);
4153 if (is_event_hup(event))
4157 * Pin the event->rb by taking event->mmap_mutex; otherwise
4158 * perf_event_set_output() can swizzle our rb and make us miss wakeups.
4160 mutex_lock(&event->mmap_mutex);
4163 events = atomic_xchg(&rb->poll, 0);
4164 mutex_unlock(&event->mmap_mutex);
4168 static void _perf_event_reset(struct perf_event *event)
4170 (void)perf_event_read(event, false);
4171 local64_set(&event->count, 0);
4172 perf_event_update_userpage(event);
4176 * Holding the top-level event's child_mutex means that any
4177 * descendant process that has inherited this event will block
4178 * in perf_event_exit_event() if it goes to exit, thus satisfying the
4179 * task existence requirements of perf_event_enable/disable.
4181 static void perf_event_for_each_child(struct perf_event *event,
4182 void (*func)(struct perf_event *))
4184 struct perf_event *child;
4186 WARN_ON_ONCE(event->ctx->parent_ctx);
4188 mutex_lock(&event->child_mutex);
4190 list_for_each_entry(child, &event->child_list, child_list)
4192 mutex_unlock(&event->child_mutex);
4195 static void perf_event_for_each(struct perf_event *event,
4196 void (*func)(struct perf_event *))
4198 struct perf_event_context *ctx = event->ctx;
4199 struct perf_event *sibling;
4201 lockdep_assert_held(&ctx->mutex);
4203 event = event->group_leader;
4205 perf_event_for_each_child(event, func);
4206 list_for_each_entry(sibling, &event->sibling_list, group_entry)
4207 perf_event_for_each_child(sibling, func);
4210 static void __perf_event_period(struct perf_event *event,
4211 struct perf_cpu_context *cpuctx,
4212 struct perf_event_context *ctx,
4215 u64 value = *((u64 *)info);
4218 if (event->attr.freq) {
4219 event->attr.sample_freq = value;
4221 event->attr.sample_period = value;
4222 event->hw.sample_period = value;
4225 active = (event->state == PERF_EVENT_STATE_ACTIVE);
4227 perf_pmu_disable(ctx->pmu);
4229 * We could be throttled; unthrottle now to avoid the tick
4230 * trying to unthrottle while we already re-started the event.
4232 if (event->hw.interrupts == MAX_INTERRUPTS) {
4233 event->hw.interrupts = 0;
4234 perf_log_throttle(event, 1);
4236 event->pmu->stop(event, PERF_EF_UPDATE);
4239 local64_set(&event->hw.period_left, 0);
4242 event->pmu->start(event, PERF_EF_RELOAD);
4243 perf_pmu_enable(ctx->pmu);
4247 static int perf_event_period(struct perf_event *event, u64 __user *arg)
4251 if (!is_sampling_event(event))
4254 if (copy_from_user(&value, arg, sizeof(value)))
4260 if (event->attr.freq && value > sysctl_perf_event_sample_rate)
4263 event_function_call(event, __perf_event_period, &value);
4268 static const struct file_operations perf_fops;
4270 static inline int perf_fget_light(int fd, struct fd *p)
4272 struct fd f = fdget(fd);
4276 if (f.file->f_op != &perf_fops) {
4284 static int perf_event_set_output(struct perf_event *event,
4285 struct perf_event *output_event);
4286 static int perf_event_set_filter(struct perf_event *event, void __user *arg);
4287 static int perf_event_set_bpf_prog(struct perf_event *event, u32 prog_fd);
4289 static long _perf_ioctl(struct perf_event *event, unsigned int cmd, unsigned long arg)
4291 void (*func)(struct perf_event *);
4295 case PERF_EVENT_IOC_ENABLE:
4296 func = _perf_event_enable;
4298 case PERF_EVENT_IOC_DISABLE:
4299 func = _perf_event_disable;
4301 case PERF_EVENT_IOC_RESET:
4302 func = _perf_event_reset;
4305 case PERF_EVENT_IOC_REFRESH:
4306 return _perf_event_refresh(event, arg);
4308 case PERF_EVENT_IOC_PERIOD:
4309 return perf_event_period(event, (u64 __user *)arg);
4311 case PERF_EVENT_IOC_ID:
4313 u64 id = primary_event_id(event);
4315 if (copy_to_user((void __user *)arg, &id, sizeof(id)))
4320 case PERF_EVENT_IOC_SET_OUTPUT:
4324 struct perf_event *output_event;
4326 ret = perf_fget_light(arg, &output);
4329 output_event = output.file->private_data;
4330 ret = perf_event_set_output(event, output_event);
4333 ret = perf_event_set_output(event, NULL);
4338 case PERF_EVENT_IOC_SET_FILTER:
4339 return perf_event_set_filter(event, (void __user *)arg);
4341 case PERF_EVENT_IOC_SET_BPF:
4342 return perf_event_set_bpf_prog(event, arg);
4348 if (flags & PERF_IOC_FLAG_GROUP)
4349 perf_event_for_each(event, func);
4351 perf_event_for_each_child(event, func);
4356 static long perf_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
4358 struct perf_event *event = file->private_data;
4359 struct perf_event_context *ctx;
4362 ctx = perf_event_ctx_lock(event);
4363 ret = _perf_ioctl(event, cmd, arg);
4364 perf_event_ctx_unlock(event, ctx);
4369 #ifdef CONFIG_COMPAT
4370 static long perf_compat_ioctl(struct file *file, unsigned int cmd,
4373 switch (_IOC_NR(cmd)) {
4374 case _IOC_NR(PERF_EVENT_IOC_SET_FILTER):
4375 case _IOC_NR(PERF_EVENT_IOC_ID):
4376 /* Fix up pointer size (usually 4 -> 8 in 32-on-64-bit case */
4377 if (_IOC_SIZE(cmd) == sizeof(compat_uptr_t)) {
4378 cmd &= ~IOCSIZE_MASK;
4379 cmd |= sizeof(void *) << IOCSIZE_SHIFT;
4383 return perf_ioctl(file, cmd, arg);
4386 # define perf_compat_ioctl NULL
4389 int perf_event_task_enable(void)
4391 struct perf_event_context *ctx;
4392 struct perf_event *event;
4394 mutex_lock(¤t->perf_event_mutex);
4395 list_for_each_entry(event, ¤t->perf_event_list, owner_entry) {
4396 ctx = perf_event_ctx_lock(event);
4397 perf_event_for_each_child(event, _perf_event_enable);
4398 perf_event_ctx_unlock(event, ctx);
4400 mutex_unlock(¤t->perf_event_mutex);
4405 int perf_event_task_disable(void)
4407 struct perf_event_context *ctx;
4408 struct perf_event *event;
4410 mutex_lock(¤t->perf_event_mutex);
4411 list_for_each_entry(event, ¤t->perf_event_list, owner_entry) {
4412 ctx = perf_event_ctx_lock(event);
4413 perf_event_for_each_child(event, _perf_event_disable);
4414 perf_event_ctx_unlock(event, ctx);
4416 mutex_unlock(¤t->perf_event_mutex);
4421 static int perf_event_index(struct perf_event *event)
4423 if (event->hw.state & PERF_HES_STOPPED)
4426 if (event->state != PERF_EVENT_STATE_ACTIVE)
4429 return event->pmu->event_idx(event);
4432 static void calc_timer_values(struct perf_event *event,
4439 *now = perf_clock();
4440 ctx_time = event->shadow_ctx_time + *now;
4441 *enabled = ctx_time - event->tstamp_enabled;
4442 *running = ctx_time - event->tstamp_running;
4445 static void perf_event_init_userpage(struct perf_event *event)
4447 struct perf_event_mmap_page *userpg;
4448 struct ring_buffer *rb;
4451 rb = rcu_dereference(event->rb);
4455 userpg = rb->user_page;
4457 /* Allow new userspace to detect that bit 0 is deprecated */
4458 userpg->cap_bit0_is_deprecated = 1;
4459 userpg->size = offsetof(struct perf_event_mmap_page, __reserved);
4460 userpg->data_offset = PAGE_SIZE;
4461 userpg->data_size = perf_data_size(rb);
4467 void __weak arch_perf_update_userpage(
4468 struct perf_event *event, struct perf_event_mmap_page *userpg, u64 now)
4473 * Callers need to ensure there can be no nesting of this function, otherwise
4474 * the seqlock logic goes bad. We can not serialize this because the arch
4475 * code calls this from NMI context.
4477 void perf_event_update_userpage(struct perf_event *event)
4479 struct perf_event_mmap_page *userpg;
4480 struct ring_buffer *rb;
4481 u64 enabled, running, now;
4484 rb = rcu_dereference(event->rb);
4489 * compute total_time_enabled, total_time_running
4490 * based on snapshot values taken when the event
4491 * was last scheduled in.
4493 * we cannot simply called update_context_time()
4494 * because of locking issue as we can be called in
4497 calc_timer_values(event, &now, &enabled, &running);
4499 userpg = rb->user_page;
4501 * Disable preemption so as to not let the corresponding user-space
4502 * spin too long if we get preempted.
4507 userpg->index = perf_event_index(event);
4508 userpg->offset = perf_event_count(event);
4510 userpg->offset -= local64_read(&event->hw.prev_count);
4512 userpg->time_enabled = enabled +
4513 atomic64_read(&event->child_total_time_enabled);
4515 userpg->time_running = running +
4516 atomic64_read(&event->child_total_time_running);
4518 arch_perf_update_userpage(event, userpg, now);
4527 static int perf_mmap_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
4529 struct perf_event *event = vma->vm_file->private_data;
4530 struct ring_buffer *rb;
4531 int ret = VM_FAULT_SIGBUS;
4533 if (vmf->flags & FAULT_FLAG_MKWRITE) {
4534 if (vmf->pgoff == 0)
4540 rb = rcu_dereference(event->rb);
4544 if (vmf->pgoff && (vmf->flags & FAULT_FLAG_WRITE))
4547 vmf->page = perf_mmap_to_page(rb, vmf->pgoff);
4551 get_page(vmf->page);
4552 vmf->page->mapping = vma->vm_file->f_mapping;
4553 vmf->page->index = vmf->pgoff;
4562 static void ring_buffer_attach(struct perf_event *event,
4563 struct ring_buffer *rb)
4565 struct ring_buffer *old_rb = NULL;
4566 unsigned long flags;
4570 * Should be impossible, we set this when removing
4571 * event->rb_entry and wait/clear when adding event->rb_entry.
4573 WARN_ON_ONCE(event->rcu_pending);
4576 spin_lock_irqsave(&old_rb->event_lock, flags);
4577 list_del_rcu(&event->rb_entry);
4578 spin_unlock_irqrestore(&old_rb->event_lock, flags);
4580 event->rcu_batches = get_state_synchronize_rcu();
4581 event->rcu_pending = 1;
4585 if (event->rcu_pending) {
4586 cond_synchronize_rcu(event->rcu_batches);
4587 event->rcu_pending = 0;
4590 spin_lock_irqsave(&rb->event_lock, flags);
4591 list_add_rcu(&event->rb_entry, &rb->event_list);
4592 spin_unlock_irqrestore(&rb->event_lock, flags);
4595 rcu_assign_pointer(event->rb, rb);
4598 ring_buffer_put(old_rb);
4600 * Since we detached before setting the new rb, so that we
4601 * could attach the new rb, we could have missed a wakeup.
4604 wake_up_all(&event->waitq);
4608 static void ring_buffer_wakeup(struct perf_event *event)
4610 struct ring_buffer *rb;
4613 rb = rcu_dereference(event->rb);
4615 list_for_each_entry_rcu(event, &rb->event_list, rb_entry)
4616 wake_up_all(&event->waitq);
4621 struct ring_buffer *ring_buffer_get(struct perf_event *event)
4623 struct ring_buffer *rb;
4626 rb = rcu_dereference(event->rb);
4628 if (!atomic_inc_not_zero(&rb->refcount))
4636 void ring_buffer_put(struct ring_buffer *rb)
4638 if (!atomic_dec_and_test(&rb->refcount))
4641 WARN_ON_ONCE(!list_empty(&rb->event_list));
4643 call_rcu(&rb->rcu_head, rb_free_rcu);
4646 static void perf_mmap_open(struct vm_area_struct *vma)
4648 struct perf_event *event = vma->vm_file->private_data;
4650 atomic_inc(&event->mmap_count);
4651 atomic_inc(&event->rb->mmap_count);
4654 atomic_inc(&event->rb->aux_mmap_count);
4656 if (event->pmu->event_mapped)
4657 event->pmu->event_mapped(event);
4661 * A buffer can be mmap()ed multiple times; either directly through the same
4662 * event, or through other events by use of perf_event_set_output().
4664 * In order to undo the VM accounting done by perf_mmap() we need to destroy
4665 * the buffer here, where we still have a VM context. This means we need
4666 * to detach all events redirecting to us.
4668 static void perf_mmap_close(struct vm_area_struct *vma)
4670 struct perf_event *event = vma->vm_file->private_data;
4672 struct ring_buffer *rb = ring_buffer_get(event);
4673 struct user_struct *mmap_user = rb->mmap_user;
4674 int mmap_locked = rb->mmap_locked;
4675 unsigned long size = perf_data_size(rb);
4677 if (event->pmu->event_unmapped)
4678 event->pmu->event_unmapped(event);
4681 * rb->aux_mmap_count will always drop before rb->mmap_count and
4682 * event->mmap_count, so it is ok to use event->mmap_mutex to
4683 * serialize with perf_mmap here.
4685 if (rb_has_aux(rb) && vma->vm_pgoff == rb->aux_pgoff &&
4686 atomic_dec_and_mutex_lock(&rb->aux_mmap_count, &event->mmap_mutex)) {
4687 atomic_long_sub(rb->aux_nr_pages, &mmap_user->locked_vm);
4688 vma->vm_mm->pinned_vm -= rb->aux_mmap_locked;
4691 mutex_unlock(&event->mmap_mutex);
4694 atomic_dec(&rb->mmap_count);
4696 if (!atomic_dec_and_mutex_lock(&event->mmap_count, &event->mmap_mutex))
4699 ring_buffer_attach(event, NULL);
4700 mutex_unlock(&event->mmap_mutex);
4702 /* If there's still other mmap()s of this buffer, we're done. */
4703 if (atomic_read(&rb->mmap_count))
4707 * No other mmap()s, detach from all other events that might redirect
4708 * into the now unreachable buffer. Somewhat complicated by the
4709 * fact that rb::event_lock otherwise nests inside mmap_mutex.
4713 list_for_each_entry_rcu(event, &rb->event_list, rb_entry) {
4714 if (!atomic_long_inc_not_zero(&event->refcount)) {
4716 * This event is en-route to free_event() which will
4717 * detach it and remove it from the list.
4723 mutex_lock(&event->mmap_mutex);
4725 * Check we didn't race with perf_event_set_output() which can
4726 * swizzle the rb from under us while we were waiting to
4727 * acquire mmap_mutex.
4729 * If we find a different rb; ignore this event, a next
4730 * iteration will no longer find it on the list. We have to
4731 * still restart the iteration to make sure we're not now
4732 * iterating the wrong list.
4734 if (event->rb == rb)
4735 ring_buffer_attach(event, NULL);
4737 mutex_unlock(&event->mmap_mutex);
4741 * Restart the iteration; either we're on the wrong list or
4742 * destroyed its integrity by doing a deletion.
4749 * It could be there's still a few 0-ref events on the list; they'll
4750 * get cleaned up by free_event() -- they'll also still have their
4751 * ref on the rb and will free it whenever they are done with it.
4753 * Aside from that, this buffer is 'fully' detached and unmapped,
4754 * undo the VM accounting.
4757 atomic_long_sub((size >> PAGE_SHIFT) + 1, &mmap_user->locked_vm);
4758 vma->vm_mm->pinned_vm -= mmap_locked;
4759 free_uid(mmap_user);
4762 ring_buffer_put(rb); /* could be last */
4765 static const struct vm_operations_struct perf_mmap_vmops = {
4766 .open = perf_mmap_open,
4767 .close = perf_mmap_close, /* non mergable */
4768 .fault = perf_mmap_fault,
4769 .page_mkwrite = perf_mmap_fault,
4772 static int perf_mmap(struct file *file, struct vm_area_struct *vma)
4774 struct perf_event *event = file->private_data;
4775 unsigned long user_locked, user_lock_limit;
4776 struct user_struct *user = current_user();
4777 unsigned long locked, lock_limit;
4778 struct ring_buffer *rb = NULL;
4779 unsigned long vma_size;
4780 unsigned long nr_pages;
4781 long user_extra = 0, extra = 0;
4782 int ret = 0, flags = 0;
4785 * Don't allow mmap() of inherited per-task counters. This would
4786 * create a performance issue due to all children writing to the
4789 if (event->cpu == -1 && event->attr.inherit)
4792 if (!(vma->vm_flags & VM_SHARED))
4795 vma_size = vma->vm_end - vma->vm_start;
4797 if (vma->vm_pgoff == 0) {
4798 nr_pages = (vma_size / PAGE_SIZE) - 1;
4801 * AUX area mapping: if rb->aux_nr_pages != 0, it's already
4802 * mapped, all subsequent mappings should have the same size
4803 * and offset. Must be above the normal perf buffer.
4805 u64 aux_offset, aux_size;
4810 nr_pages = vma_size / PAGE_SIZE;
4812 mutex_lock(&event->mmap_mutex);
4819 aux_offset = ACCESS_ONCE(rb->user_page->aux_offset);
4820 aux_size = ACCESS_ONCE(rb->user_page->aux_size);
4822 if (aux_offset < perf_data_size(rb) + PAGE_SIZE)
4825 if (aux_offset != vma->vm_pgoff << PAGE_SHIFT)
4828 /* already mapped with a different offset */
4829 if (rb_has_aux(rb) && rb->aux_pgoff != vma->vm_pgoff)
4832 if (aux_size != vma_size || aux_size != nr_pages * PAGE_SIZE)
4835 /* already mapped with a different size */
4836 if (rb_has_aux(rb) && rb->aux_nr_pages != nr_pages)
4839 if (!is_power_of_2(nr_pages))
4842 if (!atomic_inc_not_zero(&rb->mmap_count))
4845 if (rb_has_aux(rb)) {
4846 atomic_inc(&rb->aux_mmap_count);
4851 atomic_set(&rb->aux_mmap_count, 1);
4852 user_extra = nr_pages;
4858 * If we have rb pages ensure they're a power-of-two number, so we
4859 * can do bitmasks instead of modulo.
4861 if (nr_pages != 0 && !is_power_of_2(nr_pages))
4864 if (vma_size != PAGE_SIZE * (1 + nr_pages))
4867 WARN_ON_ONCE(event->ctx->parent_ctx);
4869 mutex_lock(&event->mmap_mutex);
4871 if (event->rb->nr_pages != nr_pages) {
4876 if (!atomic_inc_not_zero(&event->rb->mmap_count)) {
4878 * Raced against perf_mmap_close() through
4879 * perf_event_set_output(). Try again, hope for better
4882 mutex_unlock(&event->mmap_mutex);
4889 user_extra = nr_pages + 1;
4892 user_lock_limit = sysctl_perf_event_mlock >> (PAGE_SHIFT - 10);
4895 * Increase the limit linearly with more CPUs:
4897 user_lock_limit *= num_online_cpus();
4899 user_locked = atomic_long_read(&user->locked_vm) + user_extra;
4901 if (user_locked > user_lock_limit)
4902 extra = user_locked - user_lock_limit;
4904 lock_limit = rlimit(RLIMIT_MEMLOCK);
4905 lock_limit >>= PAGE_SHIFT;
4906 locked = vma->vm_mm->pinned_vm + extra;
4908 if ((locked > lock_limit) && perf_paranoid_tracepoint_raw() &&
4909 !capable(CAP_IPC_LOCK)) {
4914 WARN_ON(!rb && event->rb);
4916 if (vma->vm_flags & VM_WRITE)
4917 flags |= RING_BUFFER_WRITABLE;
4920 rb = rb_alloc(nr_pages,
4921 event->attr.watermark ? event->attr.wakeup_watermark : 0,
4929 atomic_set(&rb->mmap_count, 1);
4930 rb->mmap_user = get_current_user();
4931 rb->mmap_locked = extra;
4933 ring_buffer_attach(event, rb);
4935 perf_event_init_userpage(event);
4936 perf_event_update_userpage(event);
4938 ret = rb_alloc_aux(rb, event, vma->vm_pgoff, nr_pages,
4939 event->attr.aux_watermark, flags);
4941 rb->aux_mmap_locked = extra;
4946 atomic_long_add(user_extra, &user->locked_vm);
4947 vma->vm_mm->pinned_vm += extra;
4949 atomic_inc(&event->mmap_count);
4951 atomic_dec(&rb->mmap_count);
4954 mutex_unlock(&event->mmap_mutex);
4957 * Since pinned accounting is per vm we cannot allow fork() to copy our
4960 vma->vm_flags |= VM_DONTCOPY | VM_DONTEXPAND | VM_DONTDUMP;
4961 vma->vm_ops = &perf_mmap_vmops;
4963 if (event->pmu->event_mapped)
4964 event->pmu->event_mapped(event);
4969 static int perf_fasync(int fd, struct file *filp, int on)
4971 struct inode *inode = file_inode(filp);
4972 struct perf_event *event = filp->private_data;
4976 retval = fasync_helper(fd, filp, on, &event->fasync);
4977 inode_unlock(inode);
4985 static const struct file_operations perf_fops = {
4986 .llseek = no_llseek,
4987 .release = perf_release,
4990 .unlocked_ioctl = perf_ioctl,
4991 .compat_ioctl = perf_compat_ioctl,
4993 .fasync = perf_fasync,
4999 * If there's data, ensure we set the poll() state and publish everything
5000 * to user-space before waking everybody up.
5003 static inline struct fasync_struct **perf_event_fasync(struct perf_event *event)
5005 /* only the parent has fasync state */
5007 event = event->parent;
5008 return &event->fasync;
5011 void perf_event_wakeup(struct perf_event *event)
5013 ring_buffer_wakeup(event);
5015 if (event->pending_kill) {
5016 kill_fasync(perf_event_fasync(event), SIGIO, event->pending_kill);
5017 event->pending_kill = 0;
5021 static void perf_pending_event(struct irq_work *entry)
5023 struct perf_event *event = container_of(entry,
5024 struct perf_event, pending);
5027 rctx = perf_swevent_get_recursion_context();
5029 * If we 'fail' here, that's OK, it means recursion is already disabled
5030 * and we won't recurse 'further'.
5033 if (event->pending_disable) {
5034 event->pending_disable = 0;
5035 perf_event_disable_local(event);
5038 if (event->pending_wakeup) {
5039 event->pending_wakeup = 0;
5040 perf_event_wakeup(event);
5044 perf_swevent_put_recursion_context(rctx);
5048 * We assume there is only KVM supporting the callbacks.
5049 * Later on, we might change it to a list if there is
5050 * another virtualization implementation supporting the callbacks.
5052 struct perf_guest_info_callbacks *perf_guest_cbs;
5054 int perf_register_guest_info_callbacks(struct perf_guest_info_callbacks *cbs)
5056 perf_guest_cbs = cbs;
5059 EXPORT_SYMBOL_GPL(perf_register_guest_info_callbacks);
5061 int perf_unregister_guest_info_callbacks(struct perf_guest_info_callbacks *cbs)
5063 perf_guest_cbs = NULL;
5066 EXPORT_SYMBOL_GPL(perf_unregister_guest_info_callbacks);
5069 perf_output_sample_regs(struct perf_output_handle *handle,
5070 struct pt_regs *regs, u64 mask)
5074 for_each_set_bit(bit, (const unsigned long *) &mask,
5075 sizeof(mask) * BITS_PER_BYTE) {
5078 val = perf_reg_value(regs, bit);
5079 perf_output_put(handle, val);
5083 static void perf_sample_regs_user(struct perf_regs *regs_user,
5084 struct pt_regs *regs,
5085 struct pt_regs *regs_user_copy)
5087 if (user_mode(regs)) {
5088 regs_user->abi = perf_reg_abi(current);
5089 regs_user->regs = regs;
5090 } else if (current->mm) {
5091 perf_get_regs_user(regs_user, regs, regs_user_copy);
5093 regs_user->abi = PERF_SAMPLE_REGS_ABI_NONE;
5094 regs_user->regs = NULL;
5098 static void perf_sample_regs_intr(struct perf_regs *regs_intr,
5099 struct pt_regs *regs)
5101 regs_intr->regs = regs;
5102 regs_intr->abi = perf_reg_abi(current);
5107 * Get remaining task size from user stack pointer.
5109 * It'd be better to take stack vma map and limit this more
5110 * precisly, but there's no way to get it safely under interrupt,
5111 * so using TASK_SIZE as limit.
5113 static u64 perf_ustack_task_size(struct pt_regs *regs)
5115 unsigned long addr = perf_user_stack_pointer(regs);
5117 if (!addr || addr >= TASK_SIZE)
5120 return TASK_SIZE - addr;
5124 perf_sample_ustack_size(u16 stack_size, u16 header_size,
5125 struct pt_regs *regs)
5129 /* No regs, no stack pointer, no dump. */
5134 * Check if we fit in with the requested stack size into the:
5136 * If we don't, we limit the size to the TASK_SIZE.
5138 * - remaining sample size
5139 * If we don't, we customize the stack size to
5140 * fit in to the remaining sample size.
5143 task_size = min((u64) USHRT_MAX, perf_ustack_task_size(regs));
5144 stack_size = min(stack_size, (u16) task_size);
5146 /* Current header size plus static size and dynamic size. */
5147 header_size += 2 * sizeof(u64);
5149 /* Do we fit in with the current stack dump size? */
5150 if ((u16) (header_size + stack_size) < header_size) {
5152 * If we overflow the maximum size for the sample,
5153 * we customize the stack dump size to fit in.
5155 stack_size = USHRT_MAX - header_size - sizeof(u64);
5156 stack_size = round_up(stack_size, sizeof(u64));
5163 perf_output_sample_ustack(struct perf_output_handle *handle, u64 dump_size,
5164 struct pt_regs *regs)
5166 /* Case of a kernel thread, nothing to dump */
5169 perf_output_put(handle, size);
5178 * - the size requested by user or the best one we can fit
5179 * in to the sample max size
5181 * - user stack dump data
5183 * - the actual dumped size
5187 perf_output_put(handle, dump_size);
5190 sp = perf_user_stack_pointer(regs);
5191 rem = __output_copy_user(handle, (void *) sp, dump_size);
5192 dyn_size = dump_size - rem;
5194 perf_output_skip(handle, rem);
5197 perf_output_put(handle, dyn_size);
5201 static void __perf_event_header__init_id(struct perf_event_header *header,
5202 struct perf_sample_data *data,
5203 struct perf_event *event)
5205 u64 sample_type = event->attr.sample_type;
5207 data->type = sample_type;
5208 header->size += event->id_header_size;
5210 if (sample_type & PERF_SAMPLE_TID) {
5211 /* namespace issues */
5212 data->tid_entry.pid = perf_event_pid(event, current);
5213 data->tid_entry.tid = perf_event_tid(event, current);
5216 if (sample_type & PERF_SAMPLE_TIME)
5217 data->time = perf_event_clock(event);
5219 if (sample_type & (PERF_SAMPLE_ID | PERF_SAMPLE_IDENTIFIER))
5220 data->id = primary_event_id(event);
5222 if (sample_type & PERF_SAMPLE_STREAM_ID)
5223 data->stream_id = event->id;
5225 if (sample_type & PERF_SAMPLE_CPU) {
5226 data->cpu_entry.cpu = raw_smp_processor_id();
5227 data->cpu_entry.reserved = 0;
5231 void perf_event_header__init_id(struct perf_event_header *header,
5232 struct perf_sample_data *data,
5233 struct perf_event *event)
5235 if (event->attr.sample_id_all)
5236 __perf_event_header__init_id(header, data, event);
5239 static void __perf_event__output_id_sample(struct perf_output_handle *handle,
5240 struct perf_sample_data *data)
5242 u64 sample_type = data->type;
5244 if (sample_type & PERF_SAMPLE_TID)
5245 perf_output_put(handle, data->tid_entry);
5247 if (sample_type & PERF_SAMPLE_TIME)
5248 perf_output_put(handle, data->time);
5250 if (sample_type & PERF_SAMPLE_ID)
5251 perf_output_put(handle, data->id);
5253 if (sample_type & PERF_SAMPLE_STREAM_ID)
5254 perf_output_put(handle, data->stream_id);
5256 if (sample_type & PERF_SAMPLE_CPU)
5257 perf_output_put(handle, data->cpu_entry);
5259 if (sample_type & PERF_SAMPLE_IDENTIFIER)
5260 perf_output_put(handle, data->id);
5263 void perf_event__output_id_sample(struct perf_event *event,
5264 struct perf_output_handle *handle,
5265 struct perf_sample_data *sample)
5267 if (event->attr.sample_id_all)
5268 __perf_event__output_id_sample(handle, sample);
5271 static void perf_output_read_one(struct perf_output_handle *handle,
5272 struct perf_event *event,
5273 u64 enabled, u64 running)
5275 u64 read_format = event->attr.read_format;
5279 values[n++] = perf_event_count(event);
5280 if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED) {
5281 values[n++] = enabled +
5282 atomic64_read(&event->child_total_time_enabled);
5284 if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING) {
5285 values[n++] = running +
5286 atomic64_read(&event->child_total_time_running);
5288 if (read_format & PERF_FORMAT_ID)
5289 values[n++] = primary_event_id(event);
5291 __output_copy(handle, values, n * sizeof(u64));
5295 * XXX PERF_FORMAT_GROUP vs inherited events seems difficult.
5297 static void perf_output_read_group(struct perf_output_handle *handle,
5298 struct perf_event *event,
5299 u64 enabled, u64 running)
5301 struct perf_event *leader = event->group_leader, *sub;
5302 u64 read_format = event->attr.read_format;
5306 values[n++] = 1 + leader->nr_siblings;
5308 if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED)
5309 values[n++] = enabled;
5311 if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING)
5312 values[n++] = running;
5314 if (leader != event)
5315 leader->pmu->read(leader);
5317 values[n++] = perf_event_count(leader);
5318 if (read_format & PERF_FORMAT_ID)
5319 values[n++] = primary_event_id(leader);
5321 __output_copy(handle, values, n * sizeof(u64));
5323 list_for_each_entry(sub, &leader->sibling_list, group_entry) {
5326 if ((sub != event) &&
5327 (sub->state == PERF_EVENT_STATE_ACTIVE))
5328 sub->pmu->read(sub);
5330 values[n++] = perf_event_count(sub);
5331 if (read_format & PERF_FORMAT_ID)
5332 values[n++] = primary_event_id(sub);
5334 __output_copy(handle, values, n * sizeof(u64));
5338 #define PERF_FORMAT_TOTAL_TIMES (PERF_FORMAT_TOTAL_TIME_ENABLED|\
5339 PERF_FORMAT_TOTAL_TIME_RUNNING)
5341 static void perf_output_read(struct perf_output_handle *handle,
5342 struct perf_event *event)
5344 u64 enabled = 0, running = 0, now;
5345 u64 read_format = event->attr.read_format;
5348 * compute total_time_enabled, total_time_running
5349 * based on snapshot values taken when the event
5350 * was last scheduled in.
5352 * we cannot simply called update_context_time()
5353 * because of locking issue as we are called in
5356 if (read_format & PERF_FORMAT_TOTAL_TIMES)
5357 calc_timer_values(event, &now, &enabled, &running);
5359 if (event->attr.read_format & PERF_FORMAT_GROUP)
5360 perf_output_read_group(handle, event, enabled, running);
5362 perf_output_read_one(handle, event, enabled, running);
5365 void perf_output_sample(struct perf_output_handle *handle,
5366 struct perf_event_header *header,
5367 struct perf_sample_data *data,
5368 struct perf_event *event)
5370 u64 sample_type = data->type;
5372 perf_output_put(handle, *header);
5374 if (sample_type & PERF_SAMPLE_IDENTIFIER)
5375 perf_output_put(handle, data->id);
5377 if (sample_type & PERF_SAMPLE_IP)
5378 perf_output_put(handle, data->ip);
5380 if (sample_type & PERF_SAMPLE_TID)
5381 perf_output_put(handle, data->tid_entry);
5383 if (sample_type & PERF_SAMPLE_TIME)
5384 perf_output_put(handle, data->time);
5386 if (sample_type & PERF_SAMPLE_ADDR)
5387 perf_output_put(handle, data->addr);
5389 if (sample_type & PERF_SAMPLE_ID)
5390 perf_output_put(handle, data->id);
5392 if (sample_type & PERF_SAMPLE_STREAM_ID)
5393 perf_output_put(handle, data->stream_id);
5395 if (sample_type & PERF_SAMPLE_CPU)
5396 perf_output_put(handle, data->cpu_entry);
5398 if (sample_type & PERF_SAMPLE_PERIOD)
5399 perf_output_put(handle, data->period);
5401 if (sample_type & PERF_SAMPLE_READ)
5402 perf_output_read(handle, event);
5404 if (sample_type & PERF_SAMPLE_CALLCHAIN) {
5405 if (data->callchain) {
5408 if (data->callchain)
5409 size += data->callchain->nr;
5411 size *= sizeof(u64);
5413 __output_copy(handle, data->callchain, size);
5416 perf_output_put(handle, nr);
5420 if (sample_type & PERF_SAMPLE_RAW) {
5422 u32 raw_size = data->raw->size;
5423 u32 real_size = round_up(raw_size + sizeof(u32),
5424 sizeof(u64)) - sizeof(u32);
5427 perf_output_put(handle, real_size);
5428 __output_copy(handle, data->raw->data, raw_size);
5429 if (real_size - raw_size)
5430 __output_copy(handle, &zero, real_size - raw_size);
5436 .size = sizeof(u32),
5439 perf_output_put(handle, raw);
5443 if (sample_type & PERF_SAMPLE_BRANCH_STACK) {
5444 if (data->br_stack) {
5447 size = data->br_stack->nr
5448 * sizeof(struct perf_branch_entry);
5450 perf_output_put(handle, data->br_stack->nr);
5451 perf_output_copy(handle, data->br_stack->entries, size);
5454 * we always store at least the value of nr
5457 perf_output_put(handle, nr);
5461 if (sample_type & PERF_SAMPLE_REGS_USER) {
5462 u64 abi = data->regs_user.abi;
5465 * If there are no regs to dump, notice it through
5466 * first u64 being zero (PERF_SAMPLE_REGS_ABI_NONE).
5468 perf_output_put(handle, abi);
5471 u64 mask = event->attr.sample_regs_user;
5472 perf_output_sample_regs(handle,
5473 data->regs_user.regs,
5478 if (sample_type & PERF_SAMPLE_STACK_USER) {
5479 perf_output_sample_ustack(handle,
5480 data->stack_user_size,
5481 data->regs_user.regs);
5484 if (sample_type & PERF_SAMPLE_WEIGHT)
5485 perf_output_put(handle, data->weight);
5487 if (sample_type & PERF_SAMPLE_DATA_SRC)
5488 perf_output_put(handle, data->data_src.val);
5490 if (sample_type & PERF_SAMPLE_TRANSACTION)
5491 perf_output_put(handle, data->txn);
5493 if (sample_type & PERF_SAMPLE_REGS_INTR) {
5494 u64 abi = data->regs_intr.abi;
5496 * If there are no regs to dump, notice it through
5497 * first u64 being zero (PERF_SAMPLE_REGS_ABI_NONE).
5499 perf_output_put(handle, abi);
5502 u64 mask = event->attr.sample_regs_intr;
5504 perf_output_sample_regs(handle,
5505 data->regs_intr.regs,
5510 if (!event->attr.watermark) {
5511 int wakeup_events = event->attr.wakeup_events;
5513 if (wakeup_events) {
5514 struct ring_buffer *rb = handle->rb;
5515 int events = local_inc_return(&rb->events);
5517 if (events >= wakeup_events) {
5518 local_sub(wakeup_events, &rb->events);
5519 local_inc(&rb->wakeup);
5525 void perf_prepare_sample(struct perf_event_header *header,
5526 struct perf_sample_data *data,
5527 struct perf_event *event,
5528 struct pt_regs *regs)
5530 u64 sample_type = event->attr.sample_type;
5532 header->type = PERF_RECORD_SAMPLE;
5533 header->size = sizeof(*header) + event->header_size;
5536 header->misc |= perf_misc_flags(regs);
5538 __perf_event_header__init_id(header, data, event);
5540 if (sample_type & PERF_SAMPLE_IP)
5541 data->ip = perf_instruction_pointer(regs);
5543 if (sample_type & PERF_SAMPLE_CALLCHAIN) {
5546 data->callchain = perf_callchain(event, regs);
5548 if (data->callchain)
5549 size += data->callchain->nr;
5551 header->size += size * sizeof(u64);
5554 if (sample_type & PERF_SAMPLE_RAW) {
5555 int size = sizeof(u32);
5558 size += data->raw->size;
5560 size += sizeof(u32);
5562 header->size += round_up(size, sizeof(u64));
5565 if (sample_type & PERF_SAMPLE_BRANCH_STACK) {
5566 int size = sizeof(u64); /* nr */
5567 if (data->br_stack) {
5568 size += data->br_stack->nr
5569 * sizeof(struct perf_branch_entry);
5571 header->size += size;
5574 if (sample_type & (PERF_SAMPLE_REGS_USER | PERF_SAMPLE_STACK_USER))
5575 perf_sample_regs_user(&data->regs_user, regs,
5576 &data->regs_user_copy);
5578 if (sample_type & PERF_SAMPLE_REGS_USER) {
5579 /* regs dump ABI info */
5580 int size = sizeof(u64);
5582 if (data->regs_user.regs) {
5583 u64 mask = event->attr.sample_regs_user;
5584 size += hweight64(mask) * sizeof(u64);
5587 header->size += size;
5590 if (sample_type & PERF_SAMPLE_STACK_USER) {
5592 * Either we need PERF_SAMPLE_STACK_USER bit to be allways
5593 * processed as the last one or have additional check added
5594 * in case new sample type is added, because we could eat
5595 * up the rest of the sample size.
5597 u16 stack_size = event->attr.sample_stack_user;
5598 u16 size = sizeof(u64);
5600 stack_size = perf_sample_ustack_size(stack_size, header->size,
5601 data->regs_user.regs);
5604 * If there is something to dump, add space for the dump
5605 * itself and for the field that tells the dynamic size,
5606 * which is how many have been actually dumped.
5609 size += sizeof(u64) + stack_size;
5611 data->stack_user_size = stack_size;
5612 header->size += size;
5615 if (sample_type & PERF_SAMPLE_REGS_INTR) {
5616 /* regs dump ABI info */
5617 int size = sizeof(u64);
5619 perf_sample_regs_intr(&data->regs_intr, regs);
5621 if (data->regs_intr.regs) {
5622 u64 mask = event->attr.sample_regs_intr;
5624 size += hweight64(mask) * sizeof(u64);
5627 header->size += size;
5631 void perf_event_output(struct perf_event *event,
5632 struct perf_sample_data *data,
5633 struct pt_regs *regs)
5635 struct perf_output_handle handle;
5636 struct perf_event_header header;
5638 /* protect the callchain buffers */
5641 perf_prepare_sample(&header, data, event, regs);
5643 if (perf_output_begin(&handle, event, header.size))
5646 perf_output_sample(&handle, &header, data, event);
5648 perf_output_end(&handle);
5658 struct perf_read_event {
5659 struct perf_event_header header;
5666 perf_event_read_event(struct perf_event *event,
5667 struct task_struct *task)
5669 struct perf_output_handle handle;
5670 struct perf_sample_data sample;
5671 struct perf_read_event read_event = {
5673 .type = PERF_RECORD_READ,
5675 .size = sizeof(read_event) + event->read_size,
5677 .pid = perf_event_pid(event, task),
5678 .tid = perf_event_tid(event, task),
5682 perf_event_header__init_id(&read_event.header, &sample, event);
5683 ret = perf_output_begin(&handle, event, read_event.header.size);
5687 perf_output_put(&handle, read_event);
5688 perf_output_read(&handle, event);
5689 perf_event__output_id_sample(event, &handle, &sample);
5691 perf_output_end(&handle);
5694 typedef void (perf_event_aux_output_cb)(struct perf_event *event, void *data);
5697 perf_event_aux_ctx(struct perf_event_context *ctx,
5698 perf_event_aux_output_cb output,
5701 struct perf_event *event;
5703 list_for_each_entry_rcu(event, &ctx->event_list, event_entry) {
5704 if (event->state < PERF_EVENT_STATE_INACTIVE)
5706 if (!event_filter_match(event))
5708 output(event, data);
5713 perf_event_aux_task_ctx(perf_event_aux_output_cb output, void *data,
5714 struct perf_event_context *task_ctx)
5718 perf_event_aux_ctx(task_ctx, output, data);
5724 perf_event_aux(perf_event_aux_output_cb output, void *data,
5725 struct perf_event_context *task_ctx)
5727 struct perf_cpu_context *cpuctx;
5728 struct perf_event_context *ctx;
5733 * If we have task_ctx != NULL we only notify
5734 * the task context itself. The task_ctx is set
5735 * only for EXIT events before releasing task
5739 perf_event_aux_task_ctx(output, data, task_ctx);
5744 list_for_each_entry_rcu(pmu, &pmus, entry) {
5745 cpuctx = get_cpu_ptr(pmu->pmu_cpu_context);
5746 if (cpuctx->unique_pmu != pmu)
5748 perf_event_aux_ctx(&cpuctx->ctx, output, data);
5749 ctxn = pmu->task_ctx_nr;
5752 ctx = rcu_dereference(current->perf_event_ctxp[ctxn]);
5754 perf_event_aux_ctx(ctx, output, data);
5756 put_cpu_ptr(pmu->pmu_cpu_context);
5762 * task tracking -- fork/exit
5764 * enabled by: attr.comm | attr.mmap | attr.mmap2 | attr.mmap_data | attr.task
5767 struct perf_task_event {
5768 struct task_struct *task;
5769 struct perf_event_context *task_ctx;
5772 struct perf_event_header header;
5782 static int perf_event_task_match(struct perf_event *event)
5784 return event->attr.comm || event->attr.mmap ||
5785 event->attr.mmap2 || event->attr.mmap_data ||
5789 static void perf_event_task_output(struct perf_event *event,
5792 struct perf_task_event *task_event = data;
5793 struct perf_output_handle handle;
5794 struct perf_sample_data sample;
5795 struct task_struct *task = task_event->task;
5796 int ret, size = task_event->event_id.header.size;
5798 if (!perf_event_task_match(event))
5801 perf_event_header__init_id(&task_event->event_id.header, &sample, event);
5803 ret = perf_output_begin(&handle, event,
5804 task_event->event_id.header.size);
5808 task_event->event_id.pid = perf_event_pid(event, task);
5809 task_event->event_id.ppid = perf_event_pid(event, current);
5811 task_event->event_id.tid = perf_event_tid(event, task);
5812 task_event->event_id.ptid = perf_event_tid(event, current);
5814 task_event->event_id.time = perf_event_clock(event);
5816 perf_output_put(&handle, task_event->event_id);
5818 perf_event__output_id_sample(event, &handle, &sample);
5820 perf_output_end(&handle);
5822 task_event->event_id.header.size = size;
5825 static void perf_event_task(struct task_struct *task,
5826 struct perf_event_context *task_ctx,
5829 struct perf_task_event task_event;
5831 if (!atomic_read(&nr_comm_events) &&
5832 !atomic_read(&nr_mmap_events) &&
5833 !atomic_read(&nr_task_events))
5836 task_event = (struct perf_task_event){
5838 .task_ctx = task_ctx,
5841 .type = new ? PERF_RECORD_FORK : PERF_RECORD_EXIT,
5843 .size = sizeof(task_event.event_id),
5853 perf_event_aux(perf_event_task_output,
5858 void perf_event_fork(struct task_struct *task)
5860 perf_event_task(task, NULL, 1);
5867 struct perf_comm_event {
5868 struct task_struct *task;
5873 struct perf_event_header header;
5880 static int perf_event_comm_match(struct perf_event *event)
5882 return event->attr.comm;
5885 static void perf_event_comm_output(struct perf_event *event,
5888 struct perf_comm_event *comm_event = data;
5889 struct perf_output_handle handle;
5890 struct perf_sample_data sample;
5891 int size = comm_event->event_id.header.size;
5894 if (!perf_event_comm_match(event))
5897 perf_event_header__init_id(&comm_event->event_id.header, &sample, event);
5898 ret = perf_output_begin(&handle, event,
5899 comm_event->event_id.header.size);
5904 comm_event->event_id.pid = perf_event_pid(event, comm_event->task);
5905 comm_event->event_id.tid = perf_event_tid(event, comm_event->task);
5907 perf_output_put(&handle, comm_event->event_id);
5908 __output_copy(&handle, comm_event->comm,
5909 comm_event->comm_size);
5911 perf_event__output_id_sample(event, &handle, &sample);
5913 perf_output_end(&handle);
5915 comm_event->event_id.header.size = size;
5918 static void perf_event_comm_event(struct perf_comm_event *comm_event)
5920 char comm[TASK_COMM_LEN];
5923 memset(comm, 0, sizeof(comm));
5924 strlcpy(comm, comm_event->task->comm, sizeof(comm));
5925 size = ALIGN(strlen(comm)+1, sizeof(u64));
5927 comm_event->comm = comm;
5928 comm_event->comm_size = size;
5930 comm_event->event_id.header.size = sizeof(comm_event->event_id) + size;
5932 perf_event_aux(perf_event_comm_output,
5937 void perf_event_comm(struct task_struct *task, bool exec)
5939 struct perf_comm_event comm_event;
5941 if (!atomic_read(&nr_comm_events))
5944 comm_event = (struct perf_comm_event){
5950 .type = PERF_RECORD_COMM,
5951 .misc = exec ? PERF_RECORD_MISC_COMM_EXEC : 0,
5959 perf_event_comm_event(&comm_event);
5966 struct perf_mmap_event {
5967 struct vm_area_struct *vma;
5969 const char *file_name;
5977 struct perf_event_header header;
5987 static int perf_event_mmap_match(struct perf_event *event,
5990 struct perf_mmap_event *mmap_event = data;
5991 struct vm_area_struct *vma = mmap_event->vma;
5992 int executable = vma->vm_flags & VM_EXEC;
5994 return (!executable && event->attr.mmap_data) ||
5995 (executable && (event->attr.mmap || event->attr.mmap2));
5998 static void perf_event_mmap_output(struct perf_event *event,
6001 struct perf_mmap_event *mmap_event = data;
6002 struct perf_output_handle handle;
6003 struct perf_sample_data sample;
6004 int size = mmap_event->event_id.header.size;
6007 if (!perf_event_mmap_match(event, data))
6010 if (event->attr.mmap2) {
6011 mmap_event->event_id.header.type = PERF_RECORD_MMAP2;
6012 mmap_event->event_id.header.size += sizeof(mmap_event->maj);
6013 mmap_event->event_id.header.size += sizeof(mmap_event->min);
6014 mmap_event->event_id.header.size += sizeof(mmap_event->ino);
6015 mmap_event->event_id.header.size += sizeof(mmap_event->ino_generation);
6016 mmap_event->event_id.header.size += sizeof(mmap_event->prot);
6017 mmap_event->event_id.header.size += sizeof(mmap_event->flags);
6020 perf_event_header__init_id(&mmap_event->event_id.header, &sample, event);
6021 ret = perf_output_begin(&handle, event,
6022 mmap_event->event_id.header.size);
6026 mmap_event->event_id.pid = perf_event_pid(event, current);
6027 mmap_event->event_id.tid = perf_event_tid(event, current);
6029 perf_output_put(&handle, mmap_event->event_id);
6031 if (event->attr.mmap2) {
6032 perf_output_put(&handle, mmap_event->maj);
6033 perf_output_put(&handle, mmap_event->min);
6034 perf_output_put(&handle, mmap_event->ino);
6035 perf_output_put(&handle, mmap_event->ino_generation);
6036 perf_output_put(&handle, mmap_event->prot);
6037 perf_output_put(&handle, mmap_event->flags);
6040 __output_copy(&handle, mmap_event->file_name,
6041 mmap_event->file_size);
6043 perf_event__output_id_sample(event, &handle, &sample);
6045 perf_output_end(&handle);
6047 mmap_event->event_id.header.size = size;
6050 static void perf_event_mmap_event(struct perf_mmap_event *mmap_event)
6052 struct vm_area_struct *vma = mmap_event->vma;
6053 struct file *file = vma->vm_file;
6054 int maj = 0, min = 0;
6055 u64 ino = 0, gen = 0;
6056 u32 prot = 0, flags = 0;
6063 struct inode *inode;
6066 buf = kmalloc(PATH_MAX, GFP_KERNEL);
6072 * d_path() works from the end of the rb backwards, so we
6073 * need to add enough zero bytes after the string to handle
6074 * the 64bit alignment we do later.
6076 name = file_path(file, buf, PATH_MAX - sizeof(u64));
6081 inode = file_inode(vma->vm_file);
6082 dev = inode->i_sb->s_dev;
6084 gen = inode->i_generation;
6088 if (vma->vm_flags & VM_READ)
6090 if (vma->vm_flags & VM_WRITE)
6092 if (vma->vm_flags & VM_EXEC)
6095 if (vma->vm_flags & VM_MAYSHARE)
6098 flags = MAP_PRIVATE;
6100 if (vma->vm_flags & VM_DENYWRITE)
6101 flags |= MAP_DENYWRITE;
6102 if (vma->vm_flags & VM_MAYEXEC)
6103 flags |= MAP_EXECUTABLE;
6104 if (vma->vm_flags & VM_LOCKED)
6105 flags |= MAP_LOCKED;
6106 if (vma->vm_flags & VM_HUGETLB)
6107 flags |= MAP_HUGETLB;
6111 if (vma->vm_ops && vma->vm_ops->name) {
6112 name = (char *) vma->vm_ops->name(vma);
6117 name = (char *)arch_vma_name(vma);
6121 if (vma->vm_start <= vma->vm_mm->start_brk &&
6122 vma->vm_end >= vma->vm_mm->brk) {
6126 if (vma->vm_start <= vma->vm_mm->start_stack &&
6127 vma->vm_end >= vma->vm_mm->start_stack) {
6137 strlcpy(tmp, name, sizeof(tmp));
6141 * Since our buffer works in 8 byte units we need to align our string
6142 * size to a multiple of 8. However, we must guarantee the tail end is
6143 * zero'd out to avoid leaking random bits to userspace.
6145 size = strlen(name)+1;
6146 while (!IS_ALIGNED(size, sizeof(u64)))
6147 name[size++] = '\0';
6149 mmap_event->file_name = name;
6150 mmap_event->file_size = size;
6151 mmap_event->maj = maj;
6152 mmap_event->min = min;
6153 mmap_event->ino = ino;
6154 mmap_event->ino_generation = gen;
6155 mmap_event->prot = prot;
6156 mmap_event->flags = flags;
6158 if (!(vma->vm_flags & VM_EXEC))
6159 mmap_event->event_id.header.misc |= PERF_RECORD_MISC_MMAP_DATA;
6161 mmap_event->event_id.header.size = sizeof(mmap_event->event_id) + size;
6163 perf_event_aux(perf_event_mmap_output,
6170 void perf_event_mmap(struct vm_area_struct *vma)
6172 struct perf_mmap_event mmap_event;
6174 if (!atomic_read(&nr_mmap_events))
6177 mmap_event = (struct perf_mmap_event){
6183 .type = PERF_RECORD_MMAP,
6184 .misc = PERF_RECORD_MISC_USER,
6189 .start = vma->vm_start,
6190 .len = vma->vm_end - vma->vm_start,
6191 .pgoff = (u64)vma->vm_pgoff << PAGE_SHIFT,
6193 /* .maj (attr_mmap2 only) */
6194 /* .min (attr_mmap2 only) */
6195 /* .ino (attr_mmap2 only) */
6196 /* .ino_generation (attr_mmap2 only) */
6197 /* .prot (attr_mmap2 only) */
6198 /* .flags (attr_mmap2 only) */
6201 perf_event_mmap_event(&mmap_event);
6204 void perf_event_aux_event(struct perf_event *event, unsigned long head,
6205 unsigned long size, u64 flags)
6207 struct perf_output_handle handle;
6208 struct perf_sample_data sample;
6209 struct perf_aux_event {
6210 struct perf_event_header header;
6216 .type = PERF_RECORD_AUX,
6218 .size = sizeof(rec),
6226 perf_event_header__init_id(&rec.header, &sample, event);
6227 ret = perf_output_begin(&handle, event, rec.header.size);
6232 perf_output_put(&handle, rec);
6233 perf_event__output_id_sample(event, &handle, &sample);
6235 perf_output_end(&handle);
6239 * Lost/dropped samples logging
6241 void perf_log_lost_samples(struct perf_event *event, u64 lost)
6243 struct perf_output_handle handle;
6244 struct perf_sample_data sample;
6248 struct perf_event_header header;
6250 } lost_samples_event = {
6252 .type = PERF_RECORD_LOST_SAMPLES,
6254 .size = sizeof(lost_samples_event),
6259 perf_event_header__init_id(&lost_samples_event.header, &sample, event);
6261 ret = perf_output_begin(&handle, event,
6262 lost_samples_event.header.size);
6266 perf_output_put(&handle, lost_samples_event);
6267 perf_event__output_id_sample(event, &handle, &sample);
6268 perf_output_end(&handle);
6272 * context_switch tracking
6275 struct perf_switch_event {
6276 struct task_struct *task;
6277 struct task_struct *next_prev;
6280 struct perf_event_header header;
6286 static int perf_event_switch_match(struct perf_event *event)
6288 return event->attr.context_switch;
6291 static void perf_event_switch_output(struct perf_event *event, void *data)
6293 struct perf_switch_event *se = data;
6294 struct perf_output_handle handle;
6295 struct perf_sample_data sample;
6298 if (!perf_event_switch_match(event))
6301 /* Only CPU-wide events are allowed to see next/prev pid/tid */
6302 if (event->ctx->task) {
6303 se->event_id.header.type = PERF_RECORD_SWITCH;
6304 se->event_id.header.size = sizeof(se->event_id.header);
6306 se->event_id.header.type = PERF_RECORD_SWITCH_CPU_WIDE;
6307 se->event_id.header.size = sizeof(se->event_id);
6308 se->event_id.next_prev_pid =
6309 perf_event_pid(event, se->next_prev);
6310 se->event_id.next_prev_tid =
6311 perf_event_tid(event, se->next_prev);
6314 perf_event_header__init_id(&se->event_id.header, &sample, event);
6316 ret = perf_output_begin(&handle, event, se->event_id.header.size);
6320 if (event->ctx->task)
6321 perf_output_put(&handle, se->event_id.header);
6323 perf_output_put(&handle, se->event_id);
6325 perf_event__output_id_sample(event, &handle, &sample);
6327 perf_output_end(&handle);
6330 static void perf_event_switch(struct task_struct *task,
6331 struct task_struct *next_prev, bool sched_in)
6333 struct perf_switch_event switch_event;
6335 /* N.B. caller checks nr_switch_events != 0 */
6337 switch_event = (struct perf_switch_event){
6339 .next_prev = next_prev,
6343 .misc = sched_in ? 0 : PERF_RECORD_MISC_SWITCH_OUT,
6346 /* .next_prev_pid */
6347 /* .next_prev_tid */
6351 perf_event_aux(perf_event_switch_output,
6357 * IRQ throttle logging
6360 static void perf_log_throttle(struct perf_event *event, int enable)
6362 struct perf_output_handle handle;
6363 struct perf_sample_data sample;
6367 struct perf_event_header header;
6371 } throttle_event = {
6373 .type = PERF_RECORD_THROTTLE,
6375 .size = sizeof(throttle_event),
6377 .time = perf_event_clock(event),
6378 .id = primary_event_id(event),
6379 .stream_id = event->id,
6383 throttle_event.header.type = PERF_RECORD_UNTHROTTLE;
6385 perf_event_header__init_id(&throttle_event.header, &sample, event);
6387 ret = perf_output_begin(&handle, event,
6388 throttle_event.header.size);
6392 perf_output_put(&handle, throttle_event);
6393 perf_event__output_id_sample(event, &handle, &sample);
6394 perf_output_end(&handle);
6397 static void perf_log_itrace_start(struct perf_event *event)
6399 struct perf_output_handle handle;
6400 struct perf_sample_data sample;
6401 struct perf_aux_event {
6402 struct perf_event_header header;
6409 event = event->parent;
6411 if (!(event->pmu->capabilities & PERF_PMU_CAP_ITRACE) ||
6412 event->hw.itrace_started)
6415 rec.header.type = PERF_RECORD_ITRACE_START;
6416 rec.header.misc = 0;
6417 rec.header.size = sizeof(rec);
6418 rec.pid = perf_event_pid(event, current);
6419 rec.tid = perf_event_tid(event, current);
6421 perf_event_header__init_id(&rec.header, &sample, event);
6422 ret = perf_output_begin(&handle, event, rec.header.size);
6427 perf_output_put(&handle, rec);
6428 perf_event__output_id_sample(event, &handle, &sample);
6430 perf_output_end(&handle);
6434 * Generic event overflow handling, sampling.
6437 static int __perf_event_overflow(struct perf_event *event,
6438 int throttle, struct perf_sample_data *data,
6439 struct pt_regs *regs)
6441 int events = atomic_read(&event->event_limit);
6442 struct hw_perf_event *hwc = &event->hw;
6447 * Non-sampling counters might still use the PMI to fold short
6448 * hardware counters, ignore those.
6450 if (unlikely(!is_sampling_event(event)))
6453 seq = __this_cpu_read(perf_throttled_seq);
6454 if (seq != hwc->interrupts_seq) {
6455 hwc->interrupts_seq = seq;
6456 hwc->interrupts = 1;
6459 if (unlikely(throttle
6460 && hwc->interrupts >= max_samples_per_tick)) {
6461 __this_cpu_inc(perf_throttled_count);
6462 tick_dep_set_cpu(smp_processor_id(), TICK_DEP_BIT_PERF_EVENTS);
6463 hwc->interrupts = MAX_INTERRUPTS;
6464 perf_log_throttle(event, 0);
6469 if (event->attr.freq) {
6470 u64 now = perf_clock();
6471 s64 delta = now - hwc->freq_time_stamp;
6473 hwc->freq_time_stamp = now;
6475 if (delta > 0 && delta < 2*TICK_NSEC)
6476 perf_adjust_period(event, delta, hwc->last_period, true);
6480 * XXX event_limit might not quite work as expected on inherited
6484 event->pending_kill = POLL_IN;
6485 if (events && atomic_dec_and_test(&event->event_limit)) {
6487 event->pending_kill = POLL_HUP;
6488 event->pending_disable = 1;
6489 irq_work_queue(&event->pending);
6492 if (event->overflow_handler)
6493 event->overflow_handler(event, data, regs);
6495 perf_event_output(event, data, regs);
6497 if (*perf_event_fasync(event) && event->pending_kill) {
6498 event->pending_wakeup = 1;
6499 irq_work_queue(&event->pending);
6505 int perf_event_overflow(struct perf_event *event,
6506 struct perf_sample_data *data,
6507 struct pt_regs *regs)
6509 return __perf_event_overflow(event, 1, data, regs);
6513 * Generic software event infrastructure
6516 struct swevent_htable {
6517 struct swevent_hlist *swevent_hlist;
6518 struct mutex hlist_mutex;
6521 /* Recursion avoidance in each contexts */
6522 int recursion[PERF_NR_CONTEXTS];
6525 static DEFINE_PER_CPU(struct swevent_htable, swevent_htable);
6528 * We directly increment event->count and keep a second value in
6529 * event->hw.period_left to count intervals. This period event
6530 * is kept in the range [-sample_period, 0] so that we can use the
6534 u64 perf_swevent_set_period(struct perf_event *event)
6536 struct hw_perf_event *hwc = &event->hw;
6537 u64 period = hwc->last_period;
6541 hwc->last_period = hwc->sample_period;
6544 old = val = local64_read(&hwc->period_left);
6548 nr = div64_u64(period + val, period);
6549 offset = nr * period;
6551 if (local64_cmpxchg(&hwc->period_left, old, val) != old)
6557 static void perf_swevent_overflow(struct perf_event *event, u64 overflow,
6558 struct perf_sample_data *data,
6559 struct pt_regs *regs)
6561 struct hw_perf_event *hwc = &event->hw;
6565 overflow = perf_swevent_set_period(event);
6567 if (hwc->interrupts == MAX_INTERRUPTS)
6570 for (; overflow; overflow--) {
6571 if (__perf_event_overflow(event, throttle,
6574 * We inhibit the overflow from happening when
6575 * hwc->interrupts == MAX_INTERRUPTS.
6583 static void perf_swevent_event(struct perf_event *event, u64 nr,
6584 struct perf_sample_data *data,
6585 struct pt_regs *regs)
6587 struct hw_perf_event *hwc = &event->hw;
6589 local64_add(nr, &event->count);
6594 if (!is_sampling_event(event))
6597 if ((event->attr.sample_type & PERF_SAMPLE_PERIOD) && !event->attr.freq) {
6599 return perf_swevent_overflow(event, 1, data, regs);
6601 data->period = event->hw.last_period;
6603 if (nr == 1 && hwc->sample_period == 1 && !event->attr.freq)
6604 return perf_swevent_overflow(event, 1, data, regs);
6606 if (local64_add_negative(nr, &hwc->period_left))
6609 perf_swevent_overflow(event, 0, data, regs);
6612 static int perf_exclude_event(struct perf_event *event,
6613 struct pt_regs *regs)
6615 if (event->hw.state & PERF_HES_STOPPED)
6619 if (event->attr.exclude_user && user_mode(regs))
6622 if (event->attr.exclude_kernel && !user_mode(regs))
6629 static int perf_swevent_match(struct perf_event *event,
6630 enum perf_type_id type,
6632 struct perf_sample_data *data,
6633 struct pt_regs *regs)
6635 if (event->attr.type != type)
6638 if (event->attr.config != event_id)
6641 if (perf_exclude_event(event, regs))
6647 static inline u64 swevent_hash(u64 type, u32 event_id)
6649 u64 val = event_id | (type << 32);
6651 return hash_64(val, SWEVENT_HLIST_BITS);
6654 static inline struct hlist_head *
6655 __find_swevent_head(struct swevent_hlist *hlist, u64 type, u32 event_id)
6657 u64 hash = swevent_hash(type, event_id);
6659 return &hlist->heads[hash];
6662 /* For the read side: events when they trigger */
6663 static inline struct hlist_head *
6664 find_swevent_head_rcu(struct swevent_htable *swhash, u64 type, u32 event_id)
6666 struct swevent_hlist *hlist;
6668 hlist = rcu_dereference(swhash->swevent_hlist);
6672 return __find_swevent_head(hlist, type, event_id);
6675 /* For the event head insertion and removal in the hlist */
6676 static inline struct hlist_head *
6677 find_swevent_head(struct swevent_htable *swhash, struct perf_event *event)
6679 struct swevent_hlist *hlist;
6680 u32 event_id = event->attr.config;
6681 u64 type = event->attr.type;
6684 * Event scheduling is always serialized against hlist allocation
6685 * and release. Which makes the protected version suitable here.
6686 * The context lock guarantees that.
6688 hlist = rcu_dereference_protected(swhash->swevent_hlist,
6689 lockdep_is_held(&event->ctx->lock));
6693 return __find_swevent_head(hlist, type, event_id);
6696 static void do_perf_sw_event(enum perf_type_id type, u32 event_id,
6698 struct perf_sample_data *data,
6699 struct pt_regs *regs)
6701 struct swevent_htable *swhash = this_cpu_ptr(&swevent_htable);
6702 struct perf_event *event;
6703 struct hlist_head *head;
6706 head = find_swevent_head_rcu(swhash, type, event_id);
6710 hlist_for_each_entry_rcu(event, head, hlist_entry) {
6711 if (perf_swevent_match(event, type, event_id, data, regs))
6712 perf_swevent_event(event, nr, data, regs);
6718 DEFINE_PER_CPU(struct pt_regs, __perf_regs[4]);
6720 int perf_swevent_get_recursion_context(void)
6722 struct swevent_htable *swhash = this_cpu_ptr(&swevent_htable);
6724 return get_recursion_context(swhash->recursion);
6726 EXPORT_SYMBOL_GPL(perf_swevent_get_recursion_context);
6728 inline void perf_swevent_put_recursion_context(int rctx)
6730 struct swevent_htable *swhash = this_cpu_ptr(&swevent_htable);
6732 put_recursion_context(swhash->recursion, rctx);
6735 void ___perf_sw_event(u32 event_id, u64 nr, struct pt_regs *regs, u64 addr)
6737 struct perf_sample_data data;
6739 if (WARN_ON_ONCE(!regs))
6742 perf_sample_data_init(&data, addr, 0);
6743 do_perf_sw_event(PERF_TYPE_SOFTWARE, event_id, nr, &data, regs);
6746 void __perf_sw_event(u32 event_id, u64 nr, struct pt_regs *regs, u64 addr)
6750 preempt_disable_notrace();
6751 rctx = perf_swevent_get_recursion_context();
6752 if (unlikely(rctx < 0))
6755 ___perf_sw_event(event_id, nr, regs, addr);
6757 perf_swevent_put_recursion_context(rctx);
6759 preempt_enable_notrace();
6762 static void perf_swevent_read(struct perf_event *event)
6766 static int perf_swevent_add(struct perf_event *event, int flags)
6768 struct swevent_htable *swhash = this_cpu_ptr(&swevent_htable);
6769 struct hw_perf_event *hwc = &event->hw;
6770 struct hlist_head *head;
6772 if (is_sampling_event(event)) {
6773 hwc->last_period = hwc->sample_period;
6774 perf_swevent_set_period(event);
6777 hwc->state = !(flags & PERF_EF_START);
6779 head = find_swevent_head(swhash, event);
6780 if (WARN_ON_ONCE(!head))
6783 hlist_add_head_rcu(&event->hlist_entry, head);
6784 perf_event_update_userpage(event);
6789 static void perf_swevent_del(struct perf_event *event, int flags)
6791 hlist_del_rcu(&event->hlist_entry);
6794 static void perf_swevent_start(struct perf_event *event, int flags)
6796 event->hw.state = 0;
6799 static void perf_swevent_stop(struct perf_event *event, int flags)
6801 event->hw.state = PERF_HES_STOPPED;
6804 /* Deref the hlist from the update side */
6805 static inline struct swevent_hlist *
6806 swevent_hlist_deref(struct swevent_htable *swhash)
6808 return rcu_dereference_protected(swhash->swevent_hlist,
6809 lockdep_is_held(&swhash->hlist_mutex));
6812 static void swevent_hlist_release(struct swevent_htable *swhash)
6814 struct swevent_hlist *hlist = swevent_hlist_deref(swhash);
6819 RCU_INIT_POINTER(swhash->swevent_hlist, NULL);
6820 kfree_rcu(hlist, rcu_head);
6823 static void swevent_hlist_put_cpu(int cpu)
6825 struct swevent_htable *swhash = &per_cpu(swevent_htable, cpu);
6827 mutex_lock(&swhash->hlist_mutex);
6829 if (!--swhash->hlist_refcount)
6830 swevent_hlist_release(swhash);
6832 mutex_unlock(&swhash->hlist_mutex);
6835 static void swevent_hlist_put(void)
6839 for_each_possible_cpu(cpu)
6840 swevent_hlist_put_cpu(cpu);
6843 static int swevent_hlist_get_cpu(int cpu)
6845 struct swevent_htable *swhash = &per_cpu(swevent_htable, cpu);
6848 mutex_lock(&swhash->hlist_mutex);
6849 if (!swevent_hlist_deref(swhash) && cpu_online(cpu)) {
6850 struct swevent_hlist *hlist;
6852 hlist = kzalloc(sizeof(*hlist), GFP_KERNEL);
6857 rcu_assign_pointer(swhash->swevent_hlist, hlist);
6859 swhash->hlist_refcount++;
6861 mutex_unlock(&swhash->hlist_mutex);
6866 static int swevent_hlist_get(void)
6868 int err, cpu, failed_cpu;
6871 for_each_possible_cpu(cpu) {
6872 err = swevent_hlist_get_cpu(cpu);
6882 for_each_possible_cpu(cpu) {
6883 if (cpu == failed_cpu)
6885 swevent_hlist_put_cpu(cpu);
6892 struct static_key perf_swevent_enabled[PERF_COUNT_SW_MAX];
6894 static void sw_perf_event_destroy(struct perf_event *event)
6896 u64 event_id = event->attr.config;
6898 WARN_ON(event->parent);
6900 static_key_slow_dec(&perf_swevent_enabled[event_id]);
6901 swevent_hlist_put();
6904 static int perf_swevent_init(struct perf_event *event)
6906 u64 event_id = event->attr.config;
6908 if (event->attr.type != PERF_TYPE_SOFTWARE)
6912 * no branch sampling for software events
6914 if (has_branch_stack(event))
6918 case PERF_COUNT_SW_CPU_CLOCK:
6919 case PERF_COUNT_SW_TASK_CLOCK:
6926 if (event_id >= PERF_COUNT_SW_MAX)
6929 if (!event->parent) {
6932 err = swevent_hlist_get();
6936 static_key_slow_inc(&perf_swevent_enabled[event_id]);
6937 event->destroy = sw_perf_event_destroy;
6943 static struct pmu perf_swevent = {
6944 .task_ctx_nr = perf_sw_context,
6946 .capabilities = PERF_PMU_CAP_NO_NMI,
6948 .event_init = perf_swevent_init,
6949 .add = perf_swevent_add,
6950 .del = perf_swevent_del,
6951 .start = perf_swevent_start,
6952 .stop = perf_swevent_stop,
6953 .read = perf_swevent_read,
6956 #ifdef CONFIG_EVENT_TRACING
6958 static int perf_tp_filter_match(struct perf_event *event,
6959 struct perf_sample_data *data)
6961 void *record = data->raw->data;
6963 /* only top level events have filters set */
6965 event = event->parent;
6967 if (likely(!event->filter) || filter_match_preds(event->filter, record))
6972 static int perf_tp_event_match(struct perf_event *event,
6973 struct perf_sample_data *data,
6974 struct pt_regs *regs)
6976 if (event->hw.state & PERF_HES_STOPPED)
6979 * All tracepoints are from kernel-space.
6981 if (event->attr.exclude_kernel)
6984 if (!perf_tp_filter_match(event, data))
6990 void perf_tp_event(u64 addr, u64 count, void *record, int entry_size,
6991 struct pt_regs *regs, struct hlist_head *head, int rctx,
6992 struct task_struct *task)
6994 struct perf_sample_data data;
6995 struct perf_event *event;
6997 struct perf_raw_record raw = {
7002 perf_sample_data_init(&data, addr, 0);
7005 hlist_for_each_entry_rcu(event, head, hlist_entry) {
7006 if (perf_tp_event_match(event, &data, regs))
7007 perf_swevent_event(event, count, &data, regs);
7011 * If we got specified a target task, also iterate its context and
7012 * deliver this event there too.
7014 if (task && task != current) {
7015 struct perf_event_context *ctx;
7016 struct trace_entry *entry = record;
7019 ctx = rcu_dereference(task->perf_event_ctxp[perf_sw_context]);
7023 list_for_each_entry_rcu(event, &ctx->event_list, event_entry) {
7024 if (event->attr.type != PERF_TYPE_TRACEPOINT)
7026 if (event->attr.config != entry->type)
7028 if (perf_tp_event_match(event, &data, regs))
7029 perf_swevent_event(event, count, &data, regs);
7035 perf_swevent_put_recursion_context(rctx);
7037 EXPORT_SYMBOL_GPL(perf_tp_event);
7039 static void tp_perf_event_destroy(struct perf_event *event)
7041 perf_trace_destroy(event);
7044 static int perf_tp_event_init(struct perf_event *event)
7048 if (event->attr.type != PERF_TYPE_TRACEPOINT)
7052 * no branch sampling for tracepoint events
7054 if (has_branch_stack(event))
7057 err = perf_trace_init(event);
7061 event->destroy = tp_perf_event_destroy;
7066 static struct pmu perf_tracepoint = {
7067 .task_ctx_nr = perf_sw_context,
7069 .event_init = perf_tp_event_init,
7070 .add = perf_trace_add,
7071 .del = perf_trace_del,
7072 .start = perf_swevent_start,
7073 .stop = perf_swevent_stop,
7074 .read = perf_swevent_read,
7077 static inline void perf_tp_register(void)
7079 perf_pmu_register(&perf_tracepoint, "tracepoint", PERF_TYPE_TRACEPOINT);
7082 static int perf_event_set_filter(struct perf_event *event, void __user *arg)
7087 if (event->attr.type != PERF_TYPE_TRACEPOINT)
7090 filter_str = strndup_user(arg, PAGE_SIZE);
7091 if (IS_ERR(filter_str))
7092 return PTR_ERR(filter_str);
7094 ret = ftrace_profile_set_filter(event, event->attr.config, filter_str);
7100 static void perf_event_free_filter(struct perf_event *event)
7102 ftrace_profile_free_filter(event);
7105 static int perf_event_set_bpf_prog(struct perf_event *event, u32 prog_fd)
7107 struct bpf_prog *prog;
7109 if (event->attr.type != PERF_TYPE_TRACEPOINT)
7112 if (event->tp_event->prog)
7115 if (!(event->tp_event->flags & TRACE_EVENT_FL_UKPROBE))
7116 /* bpf programs can only be attached to u/kprobes */
7119 prog = bpf_prog_get(prog_fd);
7121 return PTR_ERR(prog);
7123 if (prog->type != BPF_PROG_TYPE_KPROBE) {
7124 /* valid fd, but invalid bpf program type */
7129 event->tp_event->prog = prog;
7134 static void perf_event_free_bpf_prog(struct perf_event *event)
7136 struct bpf_prog *prog;
7138 if (!event->tp_event)
7141 prog = event->tp_event->prog;
7143 event->tp_event->prog = NULL;
7150 static inline void perf_tp_register(void)
7154 static int perf_event_set_filter(struct perf_event *event, void __user *arg)
7159 static void perf_event_free_filter(struct perf_event *event)
7163 static int perf_event_set_bpf_prog(struct perf_event *event, u32 prog_fd)
7168 static void perf_event_free_bpf_prog(struct perf_event *event)
7171 #endif /* CONFIG_EVENT_TRACING */
7173 #ifdef CONFIG_HAVE_HW_BREAKPOINT
7174 void perf_bp_event(struct perf_event *bp, void *data)
7176 struct perf_sample_data sample;
7177 struct pt_regs *regs = data;
7179 perf_sample_data_init(&sample, bp->attr.bp_addr, 0);
7181 if (!bp->hw.state && !perf_exclude_event(bp, regs))
7182 perf_swevent_event(bp, 1, &sample, regs);
7187 * hrtimer based swevent callback
7190 static enum hrtimer_restart perf_swevent_hrtimer(struct hrtimer *hrtimer)
7192 enum hrtimer_restart ret = HRTIMER_RESTART;
7193 struct perf_sample_data data;
7194 struct pt_regs *regs;
7195 struct perf_event *event;
7198 event = container_of(hrtimer, struct perf_event, hw.hrtimer);
7200 if (event->state != PERF_EVENT_STATE_ACTIVE)
7201 return HRTIMER_NORESTART;
7203 event->pmu->read(event);
7205 perf_sample_data_init(&data, 0, event->hw.last_period);
7206 regs = get_irq_regs();
7208 if (regs && !perf_exclude_event(event, regs)) {
7209 if (!(event->attr.exclude_idle && is_idle_task(current)))
7210 if (__perf_event_overflow(event, 1, &data, regs))
7211 ret = HRTIMER_NORESTART;
7214 period = max_t(u64, 10000, event->hw.sample_period);
7215 hrtimer_forward_now(hrtimer, ns_to_ktime(period));
7220 static void perf_swevent_start_hrtimer(struct perf_event *event)
7222 struct hw_perf_event *hwc = &event->hw;
7225 if (!is_sampling_event(event))
7228 period = local64_read(&hwc->period_left);
7233 local64_set(&hwc->period_left, 0);
7235 period = max_t(u64, 10000, hwc->sample_period);
7237 hrtimer_start(&hwc->hrtimer, ns_to_ktime(period),
7238 HRTIMER_MODE_REL_PINNED);
7241 static void perf_swevent_cancel_hrtimer(struct perf_event *event)
7243 struct hw_perf_event *hwc = &event->hw;
7245 if (is_sampling_event(event)) {
7246 ktime_t remaining = hrtimer_get_remaining(&hwc->hrtimer);
7247 local64_set(&hwc->period_left, ktime_to_ns(remaining));
7249 hrtimer_cancel(&hwc->hrtimer);
7253 static void perf_swevent_init_hrtimer(struct perf_event *event)
7255 struct hw_perf_event *hwc = &event->hw;
7257 if (!is_sampling_event(event))
7260 hrtimer_init(&hwc->hrtimer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
7261 hwc->hrtimer.function = perf_swevent_hrtimer;
7264 * Since hrtimers have a fixed rate, we can do a static freq->period
7265 * mapping and avoid the whole period adjust feedback stuff.
7267 if (event->attr.freq) {
7268 long freq = event->attr.sample_freq;
7270 event->attr.sample_period = NSEC_PER_SEC / freq;
7271 hwc->sample_period = event->attr.sample_period;
7272 local64_set(&hwc->period_left, hwc->sample_period);
7273 hwc->last_period = hwc->sample_period;
7274 event->attr.freq = 0;
7279 * Software event: cpu wall time clock
7282 static void cpu_clock_event_update(struct perf_event *event)
7287 now = local_clock();
7288 prev = local64_xchg(&event->hw.prev_count, now);
7289 local64_add(now - prev, &event->count);
7292 static void cpu_clock_event_start(struct perf_event *event, int flags)
7294 local64_set(&event->hw.prev_count, local_clock());
7295 perf_swevent_start_hrtimer(event);
7298 static void cpu_clock_event_stop(struct perf_event *event, int flags)
7300 perf_swevent_cancel_hrtimer(event);
7301 cpu_clock_event_update(event);
7304 static int cpu_clock_event_add(struct perf_event *event, int flags)
7306 if (flags & PERF_EF_START)
7307 cpu_clock_event_start(event, flags);
7308 perf_event_update_userpage(event);
7313 static void cpu_clock_event_del(struct perf_event *event, int flags)
7315 cpu_clock_event_stop(event, flags);
7318 static void cpu_clock_event_read(struct perf_event *event)
7320 cpu_clock_event_update(event);
7323 static int cpu_clock_event_init(struct perf_event *event)
7325 if (event->attr.type != PERF_TYPE_SOFTWARE)
7328 if (event->attr.config != PERF_COUNT_SW_CPU_CLOCK)
7332 * no branch sampling for software events
7334 if (has_branch_stack(event))
7337 perf_swevent_init_hrtimer(event);
7342 static struct pmu perf_cpu_clock = {
7343 .task_ctx_nr = perf_sw_context,
7345 .capabilities = PERF_PMU_CAP_NO_NMI,
7347 .event_init = cpu_clock_event_init,
7348 .add = cpu_clock_event_add,
7349 .del = cpu_clock_event_del,
7350 .start = cpu_clock_event_start,
7351 .stop = cpu_clock_event_stop,
7352 .read = cpu_clock_event_read,
7356 * Software event: task time clock
7359 static void task_clock_event_update(struct perf_event *event, u64 now)
7364 prev = local64_xchg(&event->hw.prev_count, now);
7366 local64_add(delta, &event->count);
7369 static void task_clock_event_start(struct perf_event *event, int flags)
7371 local64_set(&event->hw.prev_count, event->ctx->time);
7372 perf_swevent_start_hrtimer(event);
7375 static void task_clock_event_stop(struct perf_event *event, int flags)
7377 perf_swevent_cancel_hrtimer(event);
7378 task_clock_event_update(event, event->ctx->time);
7381 static int task_clock_event_add(struct perf_event *event, int flags)
7383 if (flags & PERF_EF_START)
7384 task_clock_event_start(event, flags);
7385 perf_event_update_userpage(event);
7390 static void task_clock_event_del(struct perf_event *event, int flags)
7392 task_clock_event_stop(event, PERF_EF_UPDATE);
7395 static void task_clock_event_read(struct perf_event *event)
7397 u64 now = perf_clock();
7398 u64 delta = now - event->ctx->timestamp;
7399 u64 time = event->ctx->time + delta;
7401 task_clock_event_update(event, time);
7404 static int task_clock_event_init(struct perf_event *event)
7406 if (event->attr.type != PERF_TYPE_SOFTWARE)
7409 if (event->attr.config != PERF_COUNT_SW_TASK_CLOCK)
7413 * no branch sampling for software events
7415 if (has_branch_stack(event))
7418 perf_swevent_init_hrtimer(event);
7423 static struct pmu perf_task_clock = {
7424 .task_ctx_nr = perf_sw_context,
7426 .capabilities = PERF_PMU_CAP_NO_NMI,
7428 .event_init = task_clock_event_init,
7429 .add = task_clock_event_add,
7430 .del = task_clock_event_del,
7431 .start = task_clock_event_start,
7432 .stop = task_clock_event_stop,
7433 .read = task_clock_event_read,
7436 static void perf_pmu_nop_void(struct pmu *pmu)
7440 static void perf_pmu_nop_txn(struct pmu *pmu, unsigned int flags)
7444 static int perf_pmu_nop_int(struct pmu *pmu)
7449 static DEFINE_PER_CPU(unsigned int, nop_txn_flags);
7451 static void perf_pmu_start_txn(struct pmu *pmu, unsigned int flags)
7453 __this_cpu_write(nop_txn_flags, flags);
7455 if (flags & ~PERF_PMU_TXN_ADD)
7458 perf_pmu_disable(pmu);
7461 static int perf_pmu_commit_txn(struct pmu *pmu)
7463 unsigned int flags = __this_cpu_read(nop_txn_flags);
7465 __this_cpu_write(nop_txn_flags, 0);
7467 if (flags & ~PERF_PMU_TXN_ADD)
7470 perf_pmu_enable(pmu);
7474 static void perf_pmu_cancel_txn(struct pmu *pmu)
7476 unsigned int flags = __this_cpu_read(nop_txn_flags);
7478 __this_cpu_write(nop_txn_flags, 0);
7480 if (flags & ~PERF_PMU_TXN_ADD)
7483 perf_pmu_enable(pmu);
7486 static int perf_event_idx_default(struct perf_event *event)
7492 * Ensures all contexts with the same task_ctx_nr have the same
7493 * pmu_cpu_context too.
7495 static struct perf_cpu_context __percpu *find_pmu_context(int ctxn)
7502 list_for_each_entry(pmu, &pmus, entry) {
7503 if (pmu->task_ctx_nr == ctxn)
7504 return pmu->pmu_cpu_context;
7510 static void update_pmu_context(struct pmu *pmu, struct pmu *old_pmu)
7514 for_each_possible_cpu(cpu) {
7515 struct perf_cpu_context *cpuctx;
7517 cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
7519 if (cpuctx->unique_pmu == old_pmu)
7520 cpuctx->unique_pmu = pmu;
7524 static void free_pmu_context(struct pmu *pmu)
7528 mutex_lock(&pmus_lock);
7530 * Like a real lame refcount.
7532 list_for_each_entry(i, &pmus, entry) {
7533 if (i->pmu_cpu_context == pmu->pmu_cpu_context) {
7534 update_pmu_context(i, pmu);
7539 free_percpu(pmu->pmu_cpu_context);
7541 mutex_unlock(&pmus_lock);
7543 static struct idr pmu_idr;
7546 type_show(struct device *dev, struct device_attribute *attr, char *page)
7548 struct pmu *pmu = dev_get_drvdata(dev);
7550 return snprintf(page, PAGE_SIZE-1, "%d\n", pmu->type);
7552 static DEVICE_ATTR_RO(type);
7555 perf_event_mux_interval_ms_show(struct device *dev,
7556 struct device_attribute *attr,
7559 struct pmu *pmu = dev_get_drvdata(dev);
7561 return snprintf(page, PAGE_SIZE-1, "%d\n", pmu->hrtimer_interval_ms);
7564 static DEFINE_MUTEX(mux_interval_mutex);
7567 perf_event_mux_interval_ms_store(struct device *dev,
7568 struct device_attribute *attr,
7569 const char *buf, size_t count)
7571 struct pmu *pmu = dev_get_drvdata(dev);
7572 int timer, cpu, ret;
7574 ret = kstrtoint(buf, 0, &timer);
7581 /* same value, noting to do */
7582 if (timer == pmu->hrtimer_interval_ms)
7585 mutex_lock(&mux_interval_mutex);
7586 pmu->hrtimer_interval_ms = timer;
7588 /* update all cpuctx for this PMU */
7590 for_each_online_cpu(cpu) {
7591 struct perf_cpu_context *cpuctx;
7592 cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
7593 cpuctx->hrtimer_interval = ns_to_ktime(NSEC_PER_MSEC * timer);
7595 cpu_function_call(cpu,
7596 (remote_function_f)perf_mux_hrtimer_restart, cpuctx);
7599 mutex_unlock(&mux_interval_mutex);
7603 static DEVICE_ATTR_RW(perf_event_mux_interval_ms);
7605 static struct attribute *pmu_dev_attrs[] = {
7606 &dev_attr_type.attr,
7607 &dev_attr_perf_event_mux_interval_ms.attr,
7610 ATTRIBUTE_GROUPS(pmu_dev);
7612 static int pmu_bus_running;
7613 static struct bus_type pmu_bus = {
7614 .name = "event_source",
7615 .dev_groups = pmu_dev_groups,
7618 static void pmu_dev_release(struct device *dev)
7623 static int pmu_dev_alloc(struct pmu *pmu)
7627 pmu->dev = kzalloc(sizeof(struct device), GFP_KERNEL);
7631 pmu->dev->groups = pmu->attr_groups;
7632 device_initialize(pmu->dev);
7633 ret = dev_set_name(pmu->dev, "%s", pmu->name);
7637 dev_set_drvdata(pmu->dev, pmu);
7638 pmu->dev->bus = &pmu_bus;
7639 pmu->dev->release = pmu_dev_release;
7640 ret = device_add(pmu->dev);
7648 put_device(pmu->dev);
7652 static struct lock_class_key cpuctx_mutex;
7653 static struct lock_class_key cpuctx_lock;
7655 int perf_pmu_register(struct pmu *pmu, const char *name, int type)
7659 mutex_lock(&pmus_lock);
7661 pmu->pmu_disable_count = alloc_percpu(int);
7662 if (!pmu->pmu_disable_count)
7671 type = idr_alloc(&pmu_idr, pmu, PERF_TYPE_MAX, 0, GFP_KERNEL);
7679 if (pmu_bus_running) {
7680 ret = pmu_dev_alloc(pmu);
7686 pmu->pmu_cpu_context = find_pmu_context(pmu->task_ctx_nr);
7687 if (pmu->pmu_cpu_context)
7688 goto got_cpu_context;
7691 pmu->pmu_cpu_context = alloc_percpu(struct perf_cpu_context);
7692 if (!pmu->pmu_cpu_context)
7695 for_each_possible_cpu(cpu) {
7696 struct perf_cpu_context *cpuctx;
7698 cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
7699 __perf_event_init_context(&cpuctx->ctx);
7700 lockdep_set_class(&cpuctx->ctx.mutex, &cpuctx_mutex);
7701 lockdep_set_class(&cpuctx->ctx.lock, &cpuctx_lock);
7702 cpuctx->ctx.pmu = pmu;
7704 __perf_mux_hrtimer_init(cpuctx, cpu);
7706 cpuctx->unique_pmu = pmu;
7710 if (!pmu->start_txn) {
7711 if (pmu->pmu_enable) {
7713 * If we have pmu_enable/pmu_disable calls, install
7714 * transaction stubs that use that to try and batch
7715 * hardware accesses.
7717 pmu->start_txn = perf_pmu_start_txn;
7718 pmu->commit_txn = perf_pmu_commit_txn;
7719 pmu->cancel_txn = perf_pmu_cancel_txn;
7721 pmu->start_txn = perf_pmu_nop_txn;
7722 pmu->commit_txn = perf_pmu_nop_int;
7723 pmu->cancel_txn = perf_pmu_nop_void;
7727 if (!pmu->pmu_enable) {
7728 pmu->pmu_enable = perf_pmu_nop_void;
7729 pmu->pmu_disable = perf_pmu_nop_void;
7732 if (!pmu->event_idx)
7733 pmu->event_idx = perf_event_idx_default;
7735 list_add_rcu(&pmu->entry, &pmus);
7736 atomic_set(&pmu->exclusive_cnt, 0);
7739 mutex_unlock(&pmus_lock);
7744 device_del(pmu->dev);
7745 put_device(pmu->dev);
7748 if (pmu->type >= PERF_TYPE_MAX)
7749 idr_remove(&pmu_idr, pmu->type);
7752 free_percpu(pmu->pmu_disable_count);
7755 EXPORT_SYMBOL_GPL(perf_pmu_register);
7757 void perf_pmu_unregister(struct pmu *pmu)
7759 mutex_lock(&pmus_lock);
7760 list_del_rcu(&pmu->entry);
7761 mutex_unlock(&pmus_lock);
7764 * We dereference the pmu list under both SRCU and regular RCU, so
7765 * synchronize against both of those.
7767 synchronize_srcu(&pmus_srcu);
7770 free_percpu(pmu->pmu_disable_count);
7771 if (pmu->type >= PERF_TYPE_MAX)
7772 idr_remove(&pmu_idr, pmu->type);
7773 device_del(pmu->dev);
7774 put_device(pmu->dev);
7775 free_pmu_context(pmu);
7777 EXPORT_SYMBOL_GPL(perf_pmu_unregister);
7779 static int perf_try_init_event(struct pmu *pmu, struct perf_event *event)
7781 struct perf_event_context *ctx = NULL;
7784 if (!try_module_get(pmu->module))
7787 if (event->group_leader != event) {
7789 * This ctx->mutex can nest when we're called through
7790 * inheritance. See the perf_event_ctx_lock_nested() comment.
7792 ctx = perf_event_ctx_lock_nested(event->group_leader,
7793 SINGLE_DEPTH_NESTING);
7798 ret = pmu->event_init(event);
7801 perf_event_ctx_unlock(event->group_leader, ctx);
7804 module_put(pmu->module);
7809 static struct pmu *perf_init_event(struct perf_event *event)
7811 struct pmu *pmu = NULL;
7815 idx = srcu_read_lock(&pmus_srcu);
7818 pmu = idr_find(&pmu_idr, event->attr.type);
7821 ret = perf_try_init_event(pmu, event);
7827 list_for_each_entry_rcu(pmu, &pmus, entry) {
7828 ret = perf_try_init_event(pmu, event);
7832 if (ret != -ENOENT) {
7837 pmu = ERR_PTR(-ENOENT);
7839 srcu_read_unlock(&pmus_srcu, idx);
7844 static void account_event_cpu(struct perf_event *event, int cpu)
7849 if (is_cgroup_event(event))
7850 atomic_inc(&per_cpu(perf_cgroup_events, cpu));
7853 /* Freq events need the tick to stay alive (see perf_event_task_tick). */
7854 static void account_freq_event_nohz(void)
7856 #ifdef CONFIG_NO_HZ_FULL
7857 /* Lock so we don't race with concurrent unaccount */
7858 spin_lock(&nr_freq_lock);
7859 if (atomic_inc_return(&nr_freq_events) == 1)
7860 tick_nohz_dep_set(TICK_DEP_BIT_PERF_EVENTS);
7861 spin_unlock(&nr_freq_lock);
7865 static void account_freq_event(void)
7867 if (tick_nohz_full_enabled())
7868 account_freq_event_nohz();
7870 atomic_inc(&nr_freq_events);
7874 static void account_event(struct perf_event *event)
7881 if (event->attach_state & PERF_ATTACH_TASK)
7883 if (event->attr.mmap || event->attr.mmap_data)
7884 atomic_inc(&nr_mmap_events);
7885 if (event->attr.comm)
7886 atomic_inc(&nr_comm_events);
7887 if (event->attr.task)
7888 atomic_inc(&nr_task_events);
7889 if (event->attr.freq)
7890 account_freq_event();
7891 if (event->attr.context_switch) {
7892 atomic_inc(&nr_switch_events);
7895 if (has_branch_stack(event))
7897 if (is_cgroup_event(event))
7901 if (atomic_inc_not_zero(&perf_sched_count))
7904 mutex_lock(&perf_sched_mutex);
7905 if (!atomic_read(&perf_sched_count)) {
7906 static_branch_enable(&perf_sched_events);
7908 * Guarantee that all CPUs observe they key change and
7909 * call the perf scheduling hooks before proceeding to
7910 * install events that need them.
7912 synchronize_sched();
7915 * Now that we have waited for the sync_sched(), allow further
7916 * increments to by-pass the mutex.
7918 atomic_inc(&perf_sched_count);
7919 mutex_unlock(&perf_sched_mutex);
7923 account_event_cpu(event, event->cpu);
7927 * Allocate and initialize a event structure
7929 static struct perf_event *
7930 perf_event_alloc(struct perf_event_attr *attr, int cpu,
7931 struct task_struct *task,
7932 struct perf_event *group_leader,
7933 struct perf_event *parent_event,
7934 perf_overflow_handler_t overflow_handler,
7935 void *context, int cgroup_fd)
7938 struct perf_event *event;
7939 struct hw_perf_event *hwc;
7942 if ((unsigned)cpu >= nr_cpu_ids) {
7943 if (!task || cpu != -1)
7944 return ERR_PTR(-EINVAL);
7947 event = kzalloc(sizeof(*event), GFP_KERNEL);
7949 return ERR_PTR(-ENOMEM);
7952 * Single events are their own group leaders, with an
7953 * empty sibling list:
7956 group_leader = event;
7958 mutex_init(&event->child_mutex);
7959 INIT_LIST_HEAD(&event->child_list);
7961 INIT_LIST_HEAD(&event->group_entry);
7962 INIT_LIST_HEAD(&event->event_entry);
7963 INIT_LIST_HEAD(&event->sibling_list);
7964 INIT_LIST_HEAD(&event->rb_entry);
7965 INIT_LIST_HEAD(&event->active_entry);
7966 INIT_HLIST_NODE(&event->hlist_entry);
7969 init_waitqueue_head(&event->waitq);
7970 init_irq_work(&event->pending, perf_pending_event);
7972 mutex_init(&event->mmap_mutex);
7974 atomic_long_set(&event->refcount, 1);
7976 event->attr = *attr;
7977 event->group_leader = group_leader;
7981 event->parent = parent_event;
7983 event->ns = get_pid_ns(task_active_pid_ns(current));
7984 event->id = atomic64_inc_return(&perf_event_id);
7986 event->state = PERF_EVENT_STATE_INACTIVE;
7989 event->attach_state = PERF_ATTACH_TASK;
7991 * XXX pmu::event_init needs to know what task to account to
7992 * and we cannot use the ctx information because we need the
7993 * pmu before we get a ctx.
7995 event->hw.target = task;
7998 event->clock = &local_clock;
8000 event->clock = parent_event->clock;
8002 if (!overflow_handler && parent_event) {
8003 overflow_handler = parent_event->overflow_handler;
8004 context = parent_event->overflow_handler_context;
8007 event->overflow_handler = overflow_handler;
8008 event->overflow_handler_context = context;
8010 perf_event__state_init(event);
8015 hwc->sample_period = attr->sample_period;
8016 if (attr->freq && attr->sample_freq)
8017 hwc->sample_period = 1;
8018 hwc->last_period = hwc->sample_period;
8020 local64_set(&hwc->period_left, hwc->sample_period);
8023 * we currently do not support PERF_FORMAT_GROUP on inherited events
8025 if (attr->inherit && (attr->read_format & PERF_FORMAT_GROUP))
8028 if (!has_branch_stack(event))
8029 event->attr.branch_sample_type = 0;
8031 if (cgroup_fd != -1) {
8032 err = perf_cgroup_connect(cgroup_fd, event, attr, group_leader);
8037 pmu = perf_init_event(event);
8040 else if (IS_ERR(pmu)) {
8045 err = exclusive_event_init(event);
8049 if (!event->parent) {
8050 if (event->attr.sample_type & PERF_SAMPLE_CALLCHAIN) {
8051 err = get_callchain_buffers();
8057 /* symmetric to unaccount_event() in _free_event() */
8058 account_event(event);
8063 exclusive_event_destroy(event);
8067 event->destroy(event);
8068 module_put(pmu->module);
8070 if (is_cgroup_event(event))
8071 perf_detach_cgroup(event);
8073 put_pid_ns(event->ns);
8076 return ERR_PTR(err);
8079 static int perf_copy_attr(struct perf_event_attr __user *uattr,
8080 struct perf_event_attr *attr)
8085 if (!access_ok(VERIFY_WRITE, uattr, PERF_ATTR_SIZE_VER0))
8089 * zero the full structure, so that a short copy will be nice.
8091 memset(attr, 0, sizeof(*attr));
8093 ret = get_user(size, &uattr->size);
8097 if (size > PAGE_SIZE) /* silly large */
8100 if (!size) /* abi compat */
8101 size = PERF_ATTR_SIZE_VER0;
8103 if (size < PERF_ATTR_SIZE_VER0)
8107 * If we're handed a bigger struct than we know of,
8108 * ensure all the unknown bits are 0 - i.e. new
8109 * user-space does not rely on any kernel feature
8110 * extensions we dont know about yet.
8112 if (size > sizeof(*attr)) {
8113 unsigned char __user *addr;
8114 unsigned char __user *end;
8117 addr = (void __user *)uattr + sizeof(*attr);
8118 end = (void __user *)uattr + size;
8120 for (; addr < end; addr++) {
8121 ret = get_user(val, addr);
8127 size = sizeof(*attr);
8130 ret = copy_from_user(attr, uattr, size);
8134 if (attr->__reserved_1)
8137 if (attr->sample_type & ~(PERF_SAMPLE_MAX-1))
8140 if (attr->read_format & ~(PERF_FORMAT_MAX-1))
8143 if (attr->sample_type & PERF_SAMPLE_BRANCH_STACK) {
8144 u64 mask = attr->branch_sample_type;
8146 /* only using defined bits */
8147 if (mask & ~(PERF_SAMPLE_BRANCH_MAX-1))
8150 /* at least one branch bit must be set */
8151 if (!(mask & ~PERF_SAMPLE_BRANCH_PLM_ALL))
8154 /* propagate priv level, when not set for branch */
8155 if (!(mask & PERF_SAMPLE_BRANCH_PLM_ALL)) {
8157 /* exclude_kernel checked on syscall entry */
8158 if (!attr->exclude_kernel)
8159 mask |= PERF_SAMPLE_BRANCH_KERNEL;
8161 if (!attr->exclude_user)
8162 mask |= PERF_SAMPLE_BRANCH_USER;
8164 if (!attr->exclude_hv)
8165 mask |= PERF_SAMPLE_BRANCH_HV;
8167 * adjust user setting (for HW filter setup)
8169 attr->branch_sample_type = mask;
8171 /* privileged levels capture (kernel, hv): check permissions */
8172 if ((mask & PERF_SAMPLE_BRANCH_PERM_PLM)
8173 && perf_paranoid_kernel() && !capable(CAP_SYS_ADMIN))
8177 if (attr->sample_type & PERF_SAMPLE_REGS_USER) {
8178 ret = perf_reg_validate(attr->sample_regs_user);
8183 if (attr->sample_type & PERF_SAMPLE_STACK_USER) {
8184 if (!arch_perf_have_user_stack_dump())
8188 * We have __u32 type for the size, but so far
8189 * we can only use __u16 as maximum due to the
8190 * __u16 sample size limit.
8192 if (attr->sample_stack_user >= USHRT_MAX)
8194 else if (!IS_ALIGNED(attr->sample_stack_user, sizeof(u64)))
8198 if (attr->sample_type & PERF_SAMPLE_REGS_INTR)
8199 ret = perf_reg_validate(attr->sample_regs_intr);
8204 put_user(sizeof(*attr), &uattr->size);
8210 perf_event_set_output(struct perf_event *event, struct perf_event *output_event)
8212 struct ring_buffer *rb = NULL;
8218 /* don't allow circular references */
8219 if (event == output_event)
8223 * Don't allow cross-cpu buffers
8225 if (output_event->cpu != event->cpu)
8229 * If its not a per-cpu rb, it must be the same task.
8231 if (output_event->cpu == -1 && output_event->ctx != event->ctx)
8235 * Mixing clocks in the same buffer is trouble you don't need.
8237 if (output_event->clock != event->clock)
8241 * If both events generate aux data, they must be on the same PMU
8243 if (has_aux(event) && has_aux(output_event) &&
8244 event->pmu != output_event->pmu)
8248 mutex_lock(&event->mmap_mutex);
8249 /* Can't redirect output if we've got an active mmap() */
8250 if (atomic_read(&event->mmap_count))
8254 /* get the rb we want to redirect to */
8255 rb = ring_buffer_get(output_event);
8260 ring_buffer_attach(event, rb);
8264 mutex_unlock(&event->mmap_mutex);
8270 static void mutex_lock_double(struct mutex *a, struct mutex *b)
8276 mutex_lock_nested(b, SINGLE_DEPTH_NESTING);
8279 static int perf_event_set_clock(struct perf_event *event, clockid_t clk_id)
8281 bool nmi_safe = false;
8284 case CLOCK_MONOTONIC:
8285 event->clock = &ktime_get_mono_fast_ns;
8289 case CLOCK_MONOTONIC_RAW:
8290 event->clock = &ktime_get_raw_fast_ns;
8294 case CLOCK_REALTIME:
8295 event->clock = &ktime_get_real_ns;
8298 case CLOCK_BOOTTIME:
8299 event->clock = &ktime_get_boot_ns;
8303 event->clock = &ktime_get_tai_ns;
8310 if (!nmi_safe && !(event->pmu->capabilities & PERF_PMU_CAP_NO_NMI))
8317 * sys_perf_event_open - open a performance event, associate it to a task/cpu
8319 * @attr_uptr: event_id type attributes for monitoring/sampling
8322 * @group_fd: group leader event fd
8324 SYSCALL_DEFINE5(perf_event_open,
8325 struct perf_event_attr __user *, attr_uptr,
8326 pid_t, pid, int, cpu, int, group_fd, unsigned long, flags)
8328 struct perf_event *group_leader = NULL, *output_event = NULL;
8329 struct perf_event *event, *sibling;
8330 struct perf_event_attr attr;
8331 struct perf_event_context *ctx, *uninitialized_var(gctx);
8332 struct file *event_file = NULL;
8333 struct fd group = {NULL, 0};
8334 struct task_struct *task = NULL;
8339 int f_flags = O_RDWR;
8342 /* for future expandability... */
8343 if (flags & ~PERF_FLAG_ALL)
8346 err = perf_copy_attr(attr_uptr, &attr);
8350 if (!attr.exclude_kernel) {
8351 if (perf_paranoid_kernel() && !capable(CAP_SYS_ADMIN))
8356 if (attr.sample_freq > sysctl_perf_event_sample_rate)
8359 if (attr.sample_period & (1ULL << 63))
8364 * In cgroup mode, the pid argument is used to pass the fd
8365 * opened to the cgroup directory in cgroupfs. The cpu argument
8366 * designates the cpu on which to monitor threads from that
8369 if ((flags & PERF_FLAG_PID_CGROUP) && (pid == -1 || cpu == -1))
8372 if (flags & PERF_FLAG_FD_CLOEXEC)
8373 f_flags |= O_CLOEXEC;
8375 event_fd = get_unused_fd_flags(f_flags);
8379 if (group_fd != -1) {
8380 err = perf_fget_light(group_fd, &group);
8383 group_leader = group.file->private_data;
8384 if (flags & PERF_FLAG_FD_OUTPUT)
8385 output_event = group_leader;
8386 if (flags & PERF_FLAG_FD_NO_GROUP)
8387 group_leader = NULL;
8390 if (pid != -1 && !(flags & PERF_FLAG_PID_CGROUP)) {
8391 task = find_lively_task_by_vpid(pid);
8393 err = PTR_ERR(task);
8398 if (task && group_leader &&
8399 group_leader->attr.inherit != attr.inherit) {
8406 if (flags & PERF_FLAG_PID_CGROUP)
8409 event = perf_event_alloc(&attr, cpu, task, group_leader, NULL,
8410 NULL, NULL, cgroup_fd);
8411 if (IS_ERR(event)) {
8412 err = PTR_ERR(event);
8416 if (is_sampling_event(event)) {
8417 if (event->pmu->capabilities & PERF_PMU_CAP_NO_INTERRUPT) {
8424 * Special case software events and allow them to be part of
8425 * any hardware group.
8429 if (attr.use_clockid) {
8430 err = perf_event_set_clock(event, attr.clockid);
8436 (is_software_event(event) != is_software_event(group_leader))) {
8437 if (is_software_event(event)) {
8439 * If event and group_leader are not both a software
8440 * event, and event is, then group leader is not.
8442 * Allow the addition of software events to !software
8443 * groups, this is safe because software events never
8446 pmu = group_leader->pmu;
8447 } else if (is_software_event(group_leader) &&
8448 (group_leader->group_flags & PERF_GROUP_SOFTWARE)) {
8450 * In case the group is a pure software group, and we
8451 * try to add a hardware event, move the whole group to
8452 * the hardware context.
8459 * Get the target context (task or percpu):
8461 ctx = find_get_context(pmu, task, event);
8467 if ((pmu->capabilities & PERF_PMU_CAP_EXCLUSIVE) && group_leader) {
8473 put_task_struct(task);
8478 * Look up the group leader (we will attach this event to it):
8484 * Do not allow a recursive hierarchy (this new sibling
8485 * becoming part of another group-sibling):
8487 if (group_leader->group_leader != group_leader)
8490 /* All events in a group should have the same clock */
8491 if (group_leader->clock != event->clock)
8495 * Do not allow to attach to a group in a different
8496 * task or CPU context:
8500 * Make sure we're both on the same task, or both
8503 if (group_leader->ctx->task != ctx->task)
8507 * Make sure we're both events for the same CPU;
8508 * grouping events for different CPUs is broken; since
8509 * you can never concurrently schedule them anyhow.
8511 if (group_leader->cpu != event->cpu)
8514 if (group_leader->ctx != ctx)
8519 * Only a group leader can be exclusive or pinned
8521 if (attr.exclusive || attr.pinned)
8526 err = perf_event_set_output(event, output_event);
8531 event_file = anon_inode_getfile("[perf_event]", &perf_fops, event,
8533 if (IS_ERR(event_file)) {
8534 err = PTR_ERR(event_file);
8539 gctx = group_leader->ctx;
8540 mutex_lock_double(&gctx->mutex, &ctx->mutex);
8541 if (gctx->task == TASK_TOMBSTONE) {
8546 mutex_lock(&ctx->mutex);
8549 if (ctx->task == TASK_TOMBSTONE) {
8554 if (!perf_event_validate_size(event)) {
8560 * Must be under the same ctx::mutex as perf_install_in_context(),
8561 * because we need to serialize with concurrent event creation.
8563 if (!exclusive_event_installable(event, ctx)) {
8564 /* exclusive and group stuff are assumed mutually exclusive */
8565 WARN_ON_ONCE(move_group);
8571 WARN_ON_ONCE(ctx->parent_ctx);
8575 * See perf_event_ctx_lock() for comments on the details
8576 * of swizzling perf_event::ctx.
8578 perf_remove_from_context(group_leader, 0);
8580 list_for_each_entry(sibling, &group_leader->sibling_list,
8582 perf_remove_from_context(sibling, 0);
8587 * Wait for everybody to stop referencing the events through
8588 * the old lists, before installing it on new lists.
8593 * Install the group siblings before the group leader.
8595 * Because a group leader will try and install the entire group
8596 * (through the sibling list, which is still in-tact), we can
8597 * end up with siblings installed in the wrong context.
8599 * By installing siblings first we NO-OP because they're not
8600 * reachable through the group lists.
8602 list_for_each_entry(sibling, &group_leader->sibling_list,
8604 perf_event__state_init(sibling);
8605 perf_install_in_context(ctx, sibling, sibling->cpu);
8610 * Removing from the context ends up with disabled
8611 * event. What we want here is event in the initial
8612 * startup state, ready to be add into new context.
8614 perf_event__state_init(group_leader);
8615 perf_install_in_context(ctx, group_leader, group_leader->cpu);
8619 * Now that all events are installed in @ctx, nothing
8620 * references @gctx anymore, so drop the last reference we have
8627 * Precalculate sample_data sizes; do while holding ctx::mutex such
8628 * that we're serialized against further additions and before
8629 * perf_install_in_context() which is the point the event is active and
8630 * can use these values.
8632 perf_event__header_size(event);
8633 perf_event__id_header_size(event);
8635 event->owner = current;
8637 perf_install_in_context(ctx, event, event->cpu);
8638 perf_unpin_context(ctx);
8641 mutex_unlock(&gctx->mutex);
8642 mutex_unlock(&ctx->mutex);
8646 mutex_lock(¤t->perf_event_mutex);
8647 list_add_tail(&event->owner_entry, ¤t->perf_event_list);
8648 mutex_unlock(¤t->perf_event_mutex);
8651 * Drop the reference on the group_event after placing the
8652 * new event on the sibling_list. This ensures destruction
8653 * of the group leader will find the pointer to itself in
8654 * perf_group_detach().
8657 fd_install(event_fd, event_file);
8662 mutex_unlock(&gctx->mutex);
8663 mutex_unlock(&ctx->mutex);
8667 perf_unpin_context(ctx);
8671 * If event_file is set, the fput() above will have called ->release()
8672 * and that will take care of freeing the event.
8680 put_task_struct(task);
8684 put_unused_fd(event_fd);
8689 * perf_event_create_kernel_counter
8691 * @attr: attributes of the counter to create
8692 * @cpu: cpu in which the counter is bound
8693 * @task: task to profile (NULL for percpu)
8696 perf_event_create_kernel_counter(struct perf_event_attr *attr, int cpu,
8697 struct task_struct *task,
8698 perf_overflow_handler_t overflow_handler,
8701 struct perf_event_context *ctx;
8702 struct perf_event *event;
8706 * Get the target context (task or percpu):
8709 event = perf_event_alloc(attr, cpu, task, NULL, NULL,
8710 overflow_handler, context, -1);
8711 if (IS_ERR(event)) {
8712 err = PTR_ERR(event);
8716 /* Mark owner so we could distinguish it from user events. */
8717 event->owner = TASK_TOMBSTONE;
8719 ctx = find_get_context(event->pmu, task, event);
8725 WARN_ON_ONCE(ctx->parent_ctx);
8726 mutex_lock(&ctx->mutex);
8727 if (ctx->task == TASK_TOMBSTONE) {
8732 if (!exclusive_event_installable(event, ctx)) {
8737 perf_install_in_context(ctx, event, cpu);
8738 perf_unpin_context(ctx);
8739 mutex_unlock(&ctx->mutex);
8744 mutex_unlock(&ctx->mutex);
8745 perf_unpin_context(ctx);
8750 return ERR_PTR(err);
8752 EXPORT_SYMBOL_GPL(perf_event_create_kernel_counter);
8754 void perf_pmu_migrate_context(struct pmu *pmu, int src_cpu, int dst_cpu)
8756 struct perf_event_context *src_ctx;
8757 struct perf_event_context *dst_ctx;
8758 struct perf_event *event, *tmp;
8761 src_ctx = &per_cpu_ptr(pmu->pmu_cpu_context, src_cpu)->ctx;
8762 dst_ctx = &per_cpu_ptr(pmu->pmu_cpu_context, dst_cpu)->ctx;
8765 * See perf_event_ctx_lock() for comments on the details
8766 * of swizzling perf_event::ctx.
8768 mutex_lock_double(&src_ctx->mutex, &dst_ctx->mutex);
8769 list_for_each_entry_safe(event, tmp, &src_ctx->event_list,
8771 perf_remove_from_context(event, 0);
8772 unaccount_event_cpu(event, src_cpu);
8774 list_add(&event->migrate_entry, &events);
8778 * Wait for the events to quiesce before re-instating them.
8783 * Re-instate events in 2 passes.
8785 * Skip over group leaders and only install siblings on this first
8786 * pass, siblings will not get enabled without a leader, however a
8787 * leader will enable its siblings, even if those are still on the old
8790 list_for_each_entry_safe(event, tmp, &events, migrate_entry) {
8791 if (event->group_leader == event)
8794 list_del(&event->migrate_entry);
8795 if (event->state >= PERF_EVENT_STATE_OFF)
8796 event->state = PERF_EVENT_STATE_INACTIVE;
8797 account_event_cpu(event, dst_cpu);
8798 perf_install_in_context(dst_ctx, event, dst_cpu);
8803 * Once all the siblings are setup properly, install the group leaders
8806 list_for_each_entry_safe(event, tmp, &events, migrate_entry) {
8807 list_del(&event->migrate_entry);
8808 if (event->state >= PERF_EVENT_STATE_OFF)
8809 event->state = PERF_EVENT_STATE_INACTIVE;
8810 account_event_cpu(event, dst_cpu);
8811 perf_install_in_context(dst_ctx, event, dst_cpu);
8814 mutex_unlock(&dst_ctx->mutex);
8815 mutex_unlock(&src_ctx->mutex);
8817 EXPORT_SYMBOL_GPL(perf_pmu_migrate_context);
8819 static void sync_child_event(struct perf_event *child_event,
8820 struct task_struct *child)
8822 struct perf_event *parent_event = child_event->parent;
8825 if (child_event->attr.inherit_stat)
8826 perf_event_read_event(child_event, child);
8828 child_val = perf_event_count(child_event);
8831 * Add back the child's count to the parent's count:
8833 atomic64_add(child_val, &parent_event->child_count);
8834 atomic64_add(child_event->total_time_enabled,
8835 &parent_event->child_total_time_enabled);
8836 atomic64_add(child_event->total_time_running,
8837 &parent_event->child_total_time_running);
8841 perf_event_exit_event(struct perf_event *child_event,
8842 struct perf_event_context *child_ctx,
8843 struct task_struct *child)
8845 struct perf_event *parent_event = child_event->parent;
8848 * Do not destroy the 'original' grouping; because of the context
8849 * switch optimization the original events could've ended up in a
8850 * random child task.
8852 * If we were to destroy the original group, all group related
8853 * operations would cease to function properly after this random
8856 * Do destroy all inherited groups, we don't care about those
8857 * and being thorough is better.
8859 raw_spin_lock_irq(&child_ctx->lock);
8860 WARN_ON_ONCE(child_ctx->is_active);
8863 perf_group_detach(child_event);
8864 list_del_event(child_event, child_ctx);
8865 child_event->state = PERF_EVENT_STATE_EXIT; /* is_event_hup() */
8866 raw_spin_unlock_irq(&child_ctx->lock);
8869 * Parent events are governed by their filedesc, retain them.
8871 if (!parent_event) {
8872 perf_event_wakeup(child_event);
8876 * Child events can be cleaned up.
8879 sync_child_event(child_event, child);
8882 * Remove this event from the parent's list
8884 WARN_ON_ONCE(parent_event->ctx->parent_ctx);
8885 mutex_lock(&parent_event->child_mutex);
8886 list_del_init(&child_event->child_list);
8887 mutex_unlock(&parent_event->child_mutex);
8890 * Kick perf_poll() for is_event_hup().
8892 perf_event_wakeup(parent_event);
8893 free_event(child_event);
8894 put_event(parent_event);
8897 static void perf_event_exit_task_context(struct task_struct *child, int ctxn)
8899 struct perf_event_context *child_ctx, *clone_ctx = NULL;
8900 struct perf_event *child_event, *next;
8902 WARN_ON_ONCE(child != current);
8904 child_ctx = perf_pin_task_context(child, ctxn);
8909 * In order to reduce the amount of tricky in ctx tear-down, we hold
8910 * ctx::mutex over the entire thing. This serializes against almost
8911 * everything that wants to access the ctx.
8913 * The exception is sys_perf_event_open() /
8914 * perf_event_create_kernel_count() which does find_get_context()
8915 * without ctx::mutex (it cannot because of the move_group double mutex
8916 * lock thing). See the comments in perf_install_in_context().
8918 mutex_lock(&child_ctx->mutex);
8921 * In a single ctx::lock section, de-schedule the events and detach the
8922 * context from the task such that we cannot ever get it scheduled back
8925 raw_spin_lock_irq(&child_ctx->lock);
8926 task_ctx_sched_out(__get_cpu_context(child_ctx), child_ctx);
8929 * Now that the context is inactive, destroy the task <-> ctx relation
8930 * and mark the context dead.
8932 RCU_INIT_POINTER(child->perf_event_ctxp[ctxn], NULL);
8933 put_ctx(child_ctx); /* cannot be last */
8934 WRITE_ONCE(child_ctx->task, TASK_TOMBSTONE);
8935 put_task_struct(current); /* cannot be last */
8937 clone_ctx = unclone_ctx(child_ctx);
8938 raw_spin_unlock_irq(&child_ctx->lock);
8944 * Report the task dead after unscheduling the events so that we
8945 * won't get any samples after PERF_RECORD_EXIT. We can however still
8946 * get a few PERF_RECORD_READ events.
8948 perf_event_task(child, child_ctx, 0);
8950 list_for_each_entry_safe(child_event, next, &child_ctx->event_list, event_entry)
8951 perf_event_exit_event(child_event, child_ctx, child);
8953 mutex_unlock(&child_ctx->mutex);
8959 * When a child task exits, feed back event values to parent events.
8961 void perf_event_exit_task(struct task_struct *child)
8963 struct perf_event *event, *tmp;
8966 mutex_lock(&child->perf_event_mutex);
8967 list_for_each_entry_safe(event, tmp, &child->perf_event_list,
8969 list_del_init(&event->owner_entry);
8972 * Ensure the list deletion is visible before we clear
8973 * the owner, closes a race against perf_release() where
8974 * we need to serialize on the owner->perf_event_mutex.
8976 smp_store_release(&event->owner, NULL);
8978 mutex_unlock(&child->perf_event_mutex);
8980 for_each_task_context_nr(ctxn)
8981 perf_event_exit_task_context(child, ctxn);
8984 * The perf_event_exit_task_context calls perf_event_task
8985 * with child's task_ctx, which generates EXIT events for
8986 * child contexts and sets child->perf_event_ctxp[] to NULL.
8987 * At this point we need to send EXIT events to cpu contexts.
8989 perf_event_task(child, NULL, 0);
8992 static void perf_free_event(struct perf_event *event,
8993 struct perf_event_context *ctx)
8995 struct perf_event *parent = event->parent;
8997 if (WARN_ON_ONCE(!parent))
9000 mutex_lock(&parent->child_mutex);
9001 list_del_init(&event->child_list);
9002 mutex_unlock(&parent->child_mutex);
9006 raw_spin_lock_irq(&ctx->lock);
9007 perf_group_detach(event);
9008 list_del_event(event, ctx);
9009 raw_spin_unlock_irq(&ctx->lock);
9014 * Free an unexposed, unused context as created by inheritance by
9015 * perf_event_init_task below, used by fork() in case of fail.
9017 * Not all locks are strictly required, but take them anyway to be nice and
9018 * help out with the lockdep assertions.
9020 void perf_event_free_task(struct task_struct *task)
9022 struct perf_event_context *ctx;
9023 struct perf_event *event, *tmp;
9026 for_each_task_context_nr(ctxn) {
9027 ctx = task->perf_event_ctxp[ctxn];
9031 mutex_lock(&ctx->mutex);
9033 list_for_each_entry_safe(event, tmp, &ctx->pinned_groups,
9035 perf_free_event(event, ctx);
9037 list_for_each_entry_safe(event, tmp, &ctx->flexible_groups,
9039 perf_free_event(event, ctx);
9041 if (!list_empty(&ctx->pinned_groups) ||
9042 !list_empty(&ctx->flexible_groups))
9045 mutex_unlock(&ctx->mutex);
9051 void perf_event_delayed_put(struct task_struct *task)
9055 for_each_task_context_nr(ctxn)
9056 WARN_ON_ONCE(task->perf_event_ctxp[ctxn]);
9059 struct file *perf_event_get(unsigned int fd)
9063 file = fget_raw(fd);
9065 return ERR_PTR(-EBADF);
9067 if (file->f_op != &perf_fops) {
9069 return ERR_PTR(-EBADF);
9075 const struct perf_event_attr *perf_event_attrs(struct perf_event *event)
9078 return ERR_PTR(-EINVAL);
9080 return &event->attr;
9084 * inherit a event from parent task to child task:
9086 static struct perf_event *
9087 inherit_event(struct perf_event *parent_event,
9088 struct task_struct *parent,
9089 struct perf_event_context *parent_ctx,
9090 struct task_struct *child,
9091 struct perf_event *group_leader,
9092 struct perf_event_context *child_ctx)
9094 enum perf_event_active_state parent_state = parent_event->state;
9095 struct perf_event *child_event;
9096 unsigned long flags;
9099 * Instead of creating recursive hierarchies of events,
9100 * we link inherited events back to the original parent,
9101 * which has a filp for sure, which we use as the reference
9104 if (parent_event->parent)
9105 parent_event = parent_event->parent;
9107 child_event = perf_event_alloc(&parent_event->attr,
9110 group_leader, parent_event,
9112 if (IS_ERR(child_event))
9116 * is_orphaned_event() and list_add_tail(&parent_event->child_list)
9117 * must be under the same lock in order to serialize against
9118 * perf_event_release_kernel(), such that either we must observe
9119 * is_orphaned_event() or they will observe us on the child_list.
9121 mutex_lock(&parent_event->child_mutex);
9122 if (is_orphaned_event(parent_event) ||
9123 !atomic_long_inc_not_zero(&parent_event->refcount)) {
9124 mutex_unlock(&parent_event->child_mutex);
9125 free_event(child_event);
9132 * Make the child state follow the state of the parent event,
9133 * not its attr.disabled bit. We hold the parent's mutex,
9134 * so we won't race with perf_event_{en, dis}able_family.
9136 if (parent_state >= PERF_EVENT_STATE_INACTIVE)
9137 child_event->state = PERF_EVENT_STATE_INACTIVE;
9139 child_event->state = PERF_EVENT_STATE_OFF;
9141 if (parent_event->attr.freq) {
9142 u64 sample_period = parent_event->hw.sample_period;
9143 struct hw_perf_event *hwc = &child_event->hw;
9145 hwc->sample_period = sample_period;
9146 hwc->last_period = sample_period;
9148 local64_set(&hwc->period_left, sample_period);
9151 child_event->ctx = child_ctx;
9152 child_event->overflow_handler = parent_event->overflow_handler;
9153 child_event->overflow_handler_context
9154 = parent_event->overflow_handler_context;
9157 * Precalculate sample_data sizes
9159 perf_event__header_size(child_event);
9160 perf_event__id_header_size(child_event);
9163 * Link it up in the child's context:
9165 raw_spin_lock_irqsave(&child_ctx->lock, flags);
9166 add_event_to_ctx(child_event, child_ctx);
9167 raw_spin_unlock_irqrestore(&child_ctx->lock, flags);
9170 * Link this into the parent event's child list
9172 list_add_tail(&child_event->child_list, &parent_event->child_list);
9173 mutex_unlock(&parent_event->child_mutex);
9178 static int inherit_group(struct perf_event *parent_event,
9179 struct task_struct *parent,
9180 struct perf_event_context *parent_ctx,
9181 struct task_struct *child,
9182 struct perf_event_context *child_ctx)
9184 struct perf_event *leader;
9185 struct perf_event *sub;
9186 struct perf_event *child_ctr;
9188 leader = inherit_event(parent_event, parent, parent_ctx,
9189 child, NULL, child_ctx);
9191 return PTR_ERR(leader);
9192 list_for_each_entry(sub, &parent_event->sibling_list, group_entry) {
9193 child_ctr = inherit_event(sub, parent, parent_ctx,
9194 child, leader, child_ctx);
9195 if (IS_ERR(child_ctr))
9196 return PTR_ERR(child_ctr);
9202 inherit_task_group(struct perf_event *event, struct task_struct *parent,
9203 struct perf_event_context *parent_ctx,
9204 struct task_struct *child, int ctxn,
9208 struct perf_event_context *child_ctx;
9210 if (!event->attr.inherit) {
9215 child_ctx = child->perf_event_ctxp[ctxn];
9218 * This is executed from the parent task context, so
9219 * inherit events that have been marked for cloning.
9220 * First allocate and initialize a context for the
9224 child_ctx = alloc_perf_context(parent_ctx->pmu, child);
9228 child->perf_event_ctxp[ctxn] = child_ctx;
9231 ret = inherit_group(event, parent, parent_ctx,
9241 * Initialize the perf_event context in task_struct
9243 static int perf_event_init_context(struct task_struct *child, int ctxn)
9245 struct perf_event_context *child_ctx, *parent_ctx;
9246 struct perf_event_context *cloned_ctx;
9247 struct perf_event *event;
9248 struct task_struct *parent = current;
9249 int inherited_all = 1;
9250 unsigned long flags;
9253 if (likely(!parent->perf_event_ctxp[ctxn]))
9257 * If the parent's context is a clone, pin it so it won't get
9260 parent_ctx = perf_pin_task_context(parent, ctxn);
9265 * No need to check if parent_ctx != NULL here; since we saw
9266 * it non-NULL earlier, the only reason for it to become NULL
9267 * is if we exit, and since we're currently in the middle of
9268 * a fork we can't be exiting at the same time.
9272 * Lock the parent list. No need to lock the child - not PID
9273 * hashed yet and not running, so nobody can access it.
9275 mutex_lock(&parent_ctx->mutex);
9278 * We dont have to disable NMIs - we are only looking at
9279 * the list, not manipulating it:
9281 list_for_each_entry(event, &parent_ctx->pinned_groups, group_entry) {
9282 ret = inherit_task_group(event, parent, parent_ctx,
9283 child, ctxn, &inherited_all);
9289 * We can't hold ctx->lock when iterating the ->flexible_group list due
9290 * to allocations, but we need to prevent rotation because
9291 * rotate_ctx() will change the list from interrupt context.
9293 raw_spin_lock_irqsave(&parent_ctx->lock, flags);
9294 parent_ctx->rotate_disable = 1;
9295 raw_spin_unlock_irqrestore(&parent_ctx->lock, flags);
9297 list_for_each_entry(event, &parent_ctx->flexible_groups, group_entry) {
9298 ret = inherit_task_group(event, parent, parent_ctx,
9299 child, ctxn, &inherited_all);
9304 raw_spin_lock_irqsave(&parent_ctx->lock, flags);
9305 parent_ctx->rotate_disable = 0;
9307 child_ctx = child->perf_event_ctxp[ctxn];
9309 if (child_ctx && inherited_all) {
9311 * Mark the child context as a clone of the parent
9312 * context, or of whatever the parent is a clone of.
9314 * Note that if the parent is a clone, the holding of
9315 * parent_ctx->lock avoids it from being uncloned.
9317 cloned_ctx = parent_ctx->parent_ctx;
9319 child_ctx->parent_ctx = cloned_ctx;
9320 child_ctx->parent_gen = parent_ctx->parent_gen;
9322 child_ctx->parent_ctx = parent_ctx;
9323 child_ctx->parent_gen = parent_ctx->generation;
9325 get_ctx(child_ctx->parent_ctx);
9328 raw_spin_unlock_irqrestore(&parent_ctx->lock, flags);
9329 mutex_unlock(&parent_ctx->mutex);
9331 perf_unpin_context(parent_ctx);
9332 put_ctx(parent_ctx);
9338 * Initialize the perf_event context in task_struct
9340 int perf_event_init_task(struct task_struct *child)
9344 memset(child->perf_event_ctxp, 0, sizeof(child->perf_event_ctxp));
9345 mutex_init(&child->perf_event_mutex);
9346 INIT_LIST_HEAD(&child->perf_event_list);
9348 for_each_task_context_nr(ctxn) {
9349 ret = perf_event_init_context(child, ctxn);
9351 perf_event_free_task(child);
9359 static void __init perf_event_init_all_cpus(void)
9361 struct swevent_htable *swhash;
9364 for_each_possible_cpu(cpu) {
9365 swhash = &per_cpu(swevent_htable, cpu);
9366 mutex_init(&swhash->hlist_mutex);
9367 INIT_LIST_HEAD(&per_cpu(active_ctx_list, cpu));
9371 static void perf_event_init_cpu(int cpu)
9373 struct swevent_htable *swhash = &per_cpu(swevent_htable, cpu);
9375 mutex_lock(&swhash->hlist_mutex);
9376 if (swhash->hlist_refcount > 0 && !swevent_hlist_deref(swhash)) {
9377 struct swevent_hlist *hlist;
9379 hlist = kzalloc_node(sizeof(*hlist), GFP_KERNEL, cpu_to_node(cpu));
9381 rcu_assign_pointer(swhash->swevent_hlist, hlist);
9383 mutex_unlock(&swhash->hlist_mutex);
9386 #if defined CONFIG_HOTPLUG_CPU || defined CONFIG_KEXEC_CORE
9387 static void __perf_event_exit_context(void *__info)
9389 struct perf_event_context *ctx = __info;
9390 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
9391 struct perf_event *event;
9393 raw_spin_lock(&ctx->lock);
9394 list_for_each_entry(event, &ctx->event_list, event_entry)
9395 __perf_remove_from_context(event, cpuctx, ctx, (void *)DETACH_GROUP);
9396 raw_spin_unlock(&ctx->lock);
9399 static void perf_event_exit_cpu_context(int cpu)
9401 struct perf_event_context *ctx;
9405 idx = srcu_read_lock(&pmus_srcu);
9406 list_for_each_entry_rcu(pmu, &pmus, entry) {
9407 ctx = &per_cpu_ptr(pmu->pmu_cpu_context, cpu)->ctx;
9409 mutex_lock(&ctx->mutex);
9410 smp_call_function_single(cpu, __perf_event_exit_context, ctx, 1);
9411 mutex_unlock(&ctx->mutex);
9413 srcu_read_unlock(&pmus_srcu, idx);
9416 static void perf_event_exit_cpu(int cpu)
9418 perf_event_exit_cpu_context(cpu);
9421 static inline void perf_event_exit_cpu(int cpu) { }
9425 perf_reboot(struct notifier_block *notifier, unsigned long val, void *v)
9429 for_each_online_cpu(cpu)
9430 perf_event_exit_cpu(cpu);
9436 * Run the perf reboot notifier at the very last possible moment so that
9437 * the generic watchdog code runs as long as possible.
9439 static struct notifier_block perf_reboot_notifier = {
9440 .notifier_call = perf_reboot,
9441 .priority = INT_MIN,
9445 perf_cpu_notify(struct notifier_block *self, unsigned long action, void *hcpu)
9447 unsigned int cpu = (long)hcpu;
9449 switch (action & ~CPU_TASKS_FROZEN) {
9451 case CPU_UP_PREPARE:
9453 * This must be done before the CPU comes alive, because the
9454 * moment we can run tasks we can encounter (software) events.
9456 * Specifically, someone can have inherited events on kthreadd
9457 * or a pre-existing worker thread that gets re-bound.
9459 perf_event_init_cpu(cpu);
9462 case CPU_DOWN_PREPARE:
9464 * This must be done before the CPU dies because after that an
9465 * active event might want to IPI the CPU and that'll not work
9466 * so great for dead CPUs.
9468 * XXX smp_call_function_single() return -ENXIO without a warn
9469 * so we could possibly deal with this.
9471 * This is safe against new events arriving because
9472 * sys_perf_event_open() serializes against hotplug using
9473 * get_online_cpus().
9475 perf_event_exit_cpu(cpu);
9484 void __init perf_event_init(void)
9490 perf_event_init_all_cpus();
9491 init_srcu_struct(&pmus_srcu);
9492 perf_pmu_register(&perf_swevent, "software", PERF_TYPE_SOFTWARE);
9493 perf_pmu_register(&perf_cpu_clock, NULL, -1);
9494 perf_pmu_register(&perf_task_clock, NULL, -1);
9496 perf_cpu_notifier(perf_cpu_notify);
9497 register_reboot_notifier(&perf_reboot_notifier);
9499 ret = init_hw_breakpoint();
9500 WARN(ret, "hw_breakpoint initialization failed with: %d", ret);
9503 * Build time assertion that we keep the data_head at the intended
9504 * location. IOW, validation we got the __reserved[] size right.
9506 BUILD_BUG_ON((offsetof(struct perf_event_mmap_page, data_head))
9510 ssize_t perf_event_sysfs_show(struct device *dev, struct device_attribute *attr,
9513 struct perf_pmu_events_attr *pmu_attr =
9514 container_of(attr, struct perf_pmu_events_attr, attr);
9516 if (pmu_attr->event_str)
9517 return sprintf(page, "%s\n", pmu_attr->event_str);
9521 EXPORT_SYMBOL_GPL(perf_event_sysfs_show);
9523 static int __init perf_event_sysfs_init(void)
9528 mutex_lock(&pmus_lock);
9530 ret = bus_register(&pmu_bus);
9534 list_for_each_entry(pmu, &pmus, entry) {
9535 if (!pmu->name || pmu->type < 0)
9538 ret = pmu_dev_alloc(pmu);
9539 WARN(ret, "Failed to register pmu: %s, reason %d\n", pmu->name, ret);
9541 pmu_bus_running = 1;
9545 mutex_unlock(&pmus_lock);
9549 device_initcall(perf_event_sysfs_init);
9551 #ifdef CONFIG_CGROUP_PERF
9552 static struct cgroup_subsys_state *
9553 perf_cgroup_css_alloc(struct cgroup_subsys_state *parent_css)
9555 struct perf_cgroup *jc;
9557 jc = kzalloc(sizeof(*jc), GFP_KERNEL);
9559 return ERR_PTR(-ENOMEM);
9561 jc->info = alloc_percpu(struct perf_cgroup_info);
9564 return ERR_PTR(-ENOMEM);
9570 static void perf_cgroup_css_free(struct cgroup_subsys_state *css)
9572 struct perf_cgroup *jc = container_of(css, struct perf_cgroup, css);
9574 free_percpu(jc->info);
9578 static int __perf_cgroup_move(void *info)
9580 struct task_struct *task = info;
9582 perf_cgroup_switch(task, PERF_CGROUP_SWOUT | PERF_CGROUP_SWIN);
9587 static void perf_cgroup_attach(struct cgroup_taskset *tset)
9589 struct task_struct *task;
9590 struct cgroup_subsys_state *css;
9592 cgroup_taskset_for_each(task, css, tset)
9593 task_function_call(task, __perf_cgroup_move, task);
9596 struct cgroup_subsys perf_event_cgrp_subsys = {
9597 .css_alloc = perf_cgroup_css_alloc,
9598 .css_free = perf_cgroup_css_free,
9599 .attach = perf_cgroup_attach,
9601 #endif /* CONFIG_CGROUP_PERF */