2 * Performance events core code:
4 * Copyright (C) 2008 Thomas Gleixner <tglx@linutronix.de>
5 * Copyright (C) 2008-2011 Red Hat, Inc., Ingo Molnar
6 * Copyright (C) 2008-2011 Red Hat, Inc., Peter Zijlstra
7 * Copyright © 2009 Paul Mackerras, IBM Corp. <paulus@au1.ibm.com>
9 * For licensing details see kernel-base/COPYING
14 #include <linux/cpu.h>
15 #include <linux/smp.h>
16 #include <linux/idr.h>
17 #include <linux/file.h>
18 #include <linux/poll.h>
19 #include <linux/slab.h>
20 #include <linux/hash.h>
21 #include <linux/tick.h>
22 #include <linux/sysfs.h>
23 #include <linux/dcache.h>
24 #include <linux/percpu.h>
25 #include <linux/ptrace.h>
26 #include <linux/reboot.h>
27 #include <linux/vmstat.h>
28 #include <linux/device.h>
29 #include <linux/export.h>
30 #include <linux/vmalloc.h>
31 #include <linux/hardirq.h>
32 #include <linux/rculist.h>
33 #include <linux/uaccess.h>
34 #include <linux/syscalls.h>
35 #include <linux/anon_inodes.h>
36 #include <linux/kernel_stat.h>
37 #include <linux/cgroup.h>
38 #include <linux/perf_event.h>
39 #include <linux/trace_events.h>
40 #include <linux/hw_breakpoint.h>
41 #include <linux/mm_types.h>
42 #include <linux/module.h>
43 #include <linux/mman.h>
44 #include <linux/compat.h>
45 #include <linux/bpf.h>
46 #include <linux/filter.h>
47 #include <linux/namei.h>
48 #include <linux/parser.h>
52 #include <asm/irq_regs.h>
54 typedef int (*remote_function_f)(void *);
56 struct remote_function_call {
57 struct task_struct *p;
58 remote_function_f func;
63 static void remote_function(void *data)
65 struct remote_function_call *tfc = data;
66 struct task_struct *p = tfc->p;
70 if (task_cpu(p) != smp_processor_id())
74 * Now that we're on right CPU with IRQs disabled, we can test
75 * if we hit the right task without races.
78 tfc->ret = -ESRCH; /* No such (running) process */
83 tfc->ret = tfc->func(tfc->info);
87 * task_function_call - call a function on the cpu on which a task runs
88 * @p: the task to evaluate
89 * @func: the function to be called
90 * @info: the function call argument
92 * Calls the function @func when the task is currently running. This might
93 * be on the current CPU, which just calls the function directly
95 * returns: @func return value, or
96 * -ESRCH - when the process isn't running
97 * -EAGAIN - when the process moved away
100 task_function_call(struct task_struct *p, remote_function_f func, void *info)
102 struct remote_function_call data = {
111 ret = smp_call_function_single(task_cpu(p), remote_function, &data, 1);
114 } while (ret == -EAGAIN);
120 * cpu_function_call - call a function on the cpu
121 * @func: the function to be called
122 * @info: the function call argument
124 * Calls the function @func on the remote cpu.
126 * returns: @func return value or -ENXIO when the cpu is offline
128 static int cpu_function_call(int cpu, remote_function_f func, void *info)
130 struct remote_function_call data = {
134 .ret = -ENXIO, /* No such CPU */
137 smp_call_function_single(cpu, remote_function, &data, 1);
142 static inline struct perf_cpu_context *
143 __get_cpu_context(struct perf_event_context *ctx)
145 return this_cpu_ptr(ctx->pmu->pmu_cpu_context);
148 static void perf_ctx_lock(struct perf_cpu_context *cpuctx,
149 struct perf_event_context *ctx)
151 raw_spin_lock(&cpuctx->ctx.lock);
153 raw_spin_lock(&ctx->lock);
156 static void perf_ctx_unlock(struct perf_cpu_context *cpuctx,
157 struct perf_event_context *ctx)
160 raw_spin_unlock(&ctx->lock);
161 raw_spin_unlock(&cpuctx->ctx.lock);
164 #define TASK_TOMBSTONE ((void *)-1L)
166 static bool is_kernel_event(struct perf_event *event)
168 return READ_ONCE(event->owner) == TASK_TOMBSTONE;
172 * On task ctx scheduling...
174 * When !ctx->nr_events a task context will not be scheduled. This means
175 * we can disable the scheduler hooks (for performance) without leaving
176 * pending task ctx state.
178 * This however results in two special cases:
180 * - removing the last event from a task ctx; this is relatively straight
181 * forward and is done in __perf_remove_from_context.
183 * - adding the first event to a task ctx; this is tricky because we cannot
184 * rely on ctx->is_active and therefore cannot use event_function_call().
185 * See perf_install_in_context().
187 * If ctx->nr_events, then ctx->is_active and cpuctx->task_ctx are set.
190 typedef void (*event_f)(struct perf_event *, struct perf_cpu_context *,
191 struct perf_event_context *, void *);
193 struct event_function_struct {
194 struct perf_event *event;
199 static int event_function(void *info)
201 struct event_function_struct *efs = info;
202 struct perf_event *event = efs->event;
203 struct perf_event_context *ctx = event->ctx;
204 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
205 struct perf_event_context *task_ctx = cpuctx->task_ctx;
208 WARN_ON_ONCE(!irqs_disabled());
210 perf_ctx_lock(cpuctx, task_ctx);
212 * Since we do the IPI call without holding ctx->lock things can have
213 * changed, double check we hit the task we set out to hit.
216 if (ctx->task != current) {
222 * We only use event_function_call() on established contexts,
223 * and event_function() is only ever called when active (or
224 * rather, we'll have bailed in task_function_call() or the
225 * above ctx->task != current test), therefore we must have
226 * ctx->is_active here.
228 WARN_ON_ONCE(!ctx->is_active);
230 * And since we have ctx->is_active, cpuctx->task_ctx must
233 WARN_ON_ONCE(task_ctx != ctx);
235 WARN_ON_ONCE(&cpuctx->ctx != ctx);
238 efs->func(event, cpuctx, ctx, efs->data);
240 perf_ctx_unlock(cpuctx, task_ctx);
245 static void event_function_local(struct perf_event *event, event_f func, void *data)
247 struct event_function_struct efs = {
253 int ret = event_function(&efs);
257 static void event_function_call(struct perf_event *event, event_f func, void *data)
259 struct perf_event_context *ctx = event->ctx;
260 struct task_struct *task = READ_ONCE(ctx->task); /* verified in event_function */
261 struct event_function_struct efs = {
267 if (!event->parent) {
269 * If this is a !child event, we must hold ctx::mutex to
270 * stabilize the the event->ctx relation. See
271 * perf_event_ctx_lock().
273 lockdep_assert_held(&ctx->mutex);
277 cpu_function_call(event->cpu, event_function, &efs);
281 if (task == TASK_TOMBSTONE)
285 if (!task_function_call(task, event_function, &efs))
288 raw_spin_lock_irq(&ctx->lock);
290 * Reload the task pointer, it might have been changed by
291 * a concurrent perf_event_context_sched_out().
294 if (task == TASK_TOMBSTONE) {
295 raw_spin_unlock_irq(&ctx->lock);
298 if (ctx->is_active) {
299 raw_spin_unlock_irq(&ctx->lock);
302 func(event, NULL, ctx, data);
303 raw_spin_unlock_irq(&ctx->lock);
306 #define PERF_FLAG_ALL (PERF_FLAG_FD_NO_GROUP |\
307 PERF_FLAG_FD_OUTPUT |\
308 PERF_FLAG_PID_CGROUP |\
309 PERF_FLAG_FD_CLOEXEC)
312 * branch priv levels that need permission checks
314 #define PERF_SAMPLE_BRANCH_PERM_PLM \
315 (PERF_SAMPLE_BRANCH_KERNEL |\
316 PERF_SAMPLE_BRANCH_HV)
319 EVENT_FLEXIBLE = 0x1,
322 EVENT_ALL = EVENT_FLEXIBLE | EVENT_PINNED,
326 * perf_sched_events : >0 events exist
327 * perf_cgroup_events: >0 per-cpu cgroup events exist on this cpu
330 static void perf_sched_delayed(struct work_struct *work);
331 DEFINE_STATIC_KEY_FALSE(perf_sched_events);
332 static DECLARE_DELAYED_WORK(perf_sched_work, perf_sched_delayed);
333 static DEFINE_MUTEX(perf_sched_mutex);
334 static atomic_t perf_sched_count;
336 static DEFINE_PER_CPU(atomic_t, perf_cgroup_events);
337 static DEFINE_PER_CPU(int, perf_sched_cb_usages);
339 static atomic_t nr_mmap_events __read_mostly;
340 static atomic_t nr_comm_events __read_mostly;
341 static atomic_t nr_task_events __read_mostly;
342 static atomic_t nr_freq_events __read_mostly;
343 static atomic_t nr_switch_events __read_mostly;
345 static LIST_HEAD(pmus);
346 static DEFINE_MUTEX(pmus_lock);
347 static struct srcu_struct pmus_srcu;
350 * perf event paranoia level:
351 * -1 - not paranoid at all
352 * 0 - disallow raw tracepoint access for unpriv
353 * 1 - disallow cpu events for unpriv
354 * 2 - disallow kernel profiling for unpriv
356 int sysctl_perf_event_paranoid __read_mostly = 2;
358 /* Minimum for 512 kiB + 1 user control page */
359 int sysctl_perf_event_mlock __read_mostly = 512 + (PAGE_SIZE / 1024); /* 'free' kiB per user */
362 * max perf event sample rate
364 #define DEFAULT_MAX_SAMPLE_RATE 100000
365 #define DEFAULT_SAMPLE_PERIOD_NS (NSEC_PER_SEC / DEFAULT_MAX_SAMPLE_RATE)
366 #define DEFAULT_CPU_TIME_MAX_PERCENT 25
368 int sysctl_perf_event_sample_rate __read_mostly = DEFAULT_MAX_SAMPLE_RATE;
370 static int max_samples_per_tick __read_mostly = DIV_ROUND_UP(DEFAULT_MAX_SAMPLE_RATE, HZ);
371 static int perf_sample_period_ns __read_mostly = DEFAULT_SAMPLE_PERIOD_NS;
373 static int perf_sample_allowed_ns __read_mostly =
374 DEFAULT_SAMPLE_PERIOD_NS * DEFAULT_CPU_TIME_MAX_PERCENT / 100;
376 static void update_perf_cpu_limits(void)
378 u64 tmp = perf_sample_period_ns;
380 tmp *= sysctl_perf_cpu_time_max_percent;
381 tmp = div_u64(tmp, 100);
385 WRITE_ONCE(perf_sample_allowed_ns, tmp);
388 static int perf_rotate_context(struct perf_cpu_context *cpuctx);
390 int perf_proc_update_handler(struct ctl_table *table, int write,
391 void __user *buffer, size_t *lenp,
394 int ret = proc_dointvec_minmax(table, write, buffer, lenp, ppos);
399 max_samples_per_tick = DIV_ROUND_UP(sysctl_perf_event_sample_rate, HZ);
400 perf_sample_period_ns = NSEC_PER_SEC / sysctl_perf_event_sample_rate;
401 update_perf_cpu_limits();
406 int sysctl_perf_cpu_time_max_percent __read_mostly = DEFAULT_CPU_TIME_MAX_PERCENT;
408 int perf_cpu_time_max_percent_handler(struct ctl_table *table, int write,
409 void __user *buffer, size_t *lenp,
412 int ret = proc_dointvec(table, write, buffer, lenp, ppos);
417 if (sysctl_perf_cpu_time_max_percent == 100 ||
418 sysctl_perf_cpu_time_max_percent == 0) {
420 "perf: Dynamic interrupt throttling disabled, can hang your system!\n");
421 WRITE_ONCE(perf_sample_allowed_ns, 0);
423 update_perf_cpu_limits();
430 * perf samples are done in some very critical code paths (NMIs).
431 * If they take too much CPU time, the system can lock up and not
432 * get any real work done. This will drop the sample rate when
433 * we detect that events are taking too long.
435 #define NR_ACCUMULATED_SAMPLES 128
436 static DEFINE_PER_CPU(u64, running_sample_length);
438 static u64 __report_avg;
439 static u64 __report_allowed;
441 static void perf_duration_warn(struct irq_work *w)
443 printk_ratelimited(KERN_WARNING
444 "perf: interrupt took too long (%lld > %lld), lowering "
445 "kernel.perf_event_max_sample_rate to %d\n",
446 __report_avg, __report_allowed,
447 sysctl_perf_event_sample_rate);
450 static DEFINE_IRQ_WORK(perf_duration_work, perf_duration_warn);
452 void perf_sample_event_took(u64 sample_len_ns)
454 u64 max_len = READ_ONCE(perf_sample_allowed_ns);
462 /* Decay the counter by 1 average sample. */
463 running_len = __this_cpu_read(running_sample_length);
464 running_len -= running_len/NR_ACCUMULATED_SAMPLES;
465 running_len += sample_len_ns;
466 __this_cpu_write(running_sample_length, running_len);
469 * Note: this will be biased artifically low until we have
470 * seen NR_ACCUMULATED_SAMPLES. Doing it this way keeps us
471 * from having to maintain a count.
473 avg_len = running_len/NR_ACCUMULATED_SAMPLES;
474 if (avg_len <= max_len)
477 __report_avg = avg_len;
478 __report_allowed = max_len;
481 * Compute a throttle threshold 25% below the current duration.
483 avg_len += avg_len / 4;
484 max = (TICK_NSEC / 100) * sysctl_perf_cpu_time_max_percent;
490 WRITE_ONCE(perf_sample_allowed_ns, avg_len);
491 WRITE_ONCE(max_samples_per_tick, max);
493 sysctl_perf_event_sample_rate = max * HZ;
494 perf_sample_period_ns = NSEC_PER_SEC / sysctl_perf_event_sample_rate;
496 if (!irq_work_queue(&perf_duration_work)) {
497 early_printk("perf: interrupt took too long (%lld > %lld), lowering "
498 "kernel.perf_event_max_sample_rate to %d\n",
499 __report_avg, __report_allowed,
500 sysctl_perf_event_sample_rate);
504 static atomic64_t perf_event_id;
506 static void cpu_ctx_sched_out(struct perf_cpu_context *cpuctx,
507 enum event_type_t event_type);
509 static void cpu_ctx_sched_in(struct perf_cpu_context *cpuctx,
510 enum event_type_t event_type,
511 struct task_struct *task);
513 static void update_context_time(struct perf_event_context *ctx);
514 static u64 perf_event_time(struct perf_event *event);
516 void __weak perf_event_print_debug(void) { }
518 extern __weak const char *perf_pmu_name(void)
523 static inline u64 perf_clock(void)
525 return local_clock();
528 static inline u64 perf_event_clock(struct perf_event *event)
530 return event->clock();
533 #ifdef CONFIG_CGROUP_PERF
536 perf_cgroup_match(struct perf_event *event)
538 struct perf_event_context *ctx = event->ctx;
539 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
541 /* @event doesn't care about cgroup */
545 /* wants specific cgroup scope but @cpuctx isn't associated with any */
550 * Cgroup scoping is recursive. An event enabled for a cgroup is
551 * also enabled for all its descendant cgroups. If @cpuctx's
552 * cgroup is a descendant of @event's (the test covers identity
553 * case), it's a match.
555 return cgroup_is_descendant(cpuctx->cgrp->css.cgroup,
556 event->cgrp->css.cgroup);
559 static inline void perf_detach_cgroup(struct perf_event *event)
561 css_put(&event->cgrp->css);
565 static inline int is_cgroup_event(struct perf_event *event)
567 return event->cgrp != NULL;
570 static inline u64 perf_cgroup_event_time(struct perf_event *event)
572 struct perf_cgroup_info *t;
574 t = per_cpu_ptr(event->cgrp->info, event->cpu);
578 static inline void __update_cgrp_time(struct perf_cgroup *cgrp)
580 struct perf_cgroup_info *info;
585 info = this_cpu_ptr(cgrp->info);
587 info->time += now - info->timestamp;
588 info->timestamp = now;
591 static inline void update_cgrp_time_from_cpuctx(struct perf_cpu_context *cpuctx)
593 struct perf_cgroup *cgrp_out = cpuctx->cgrp;
595 __update_cgrp_time(cgrp_out);
598 static inline void update_cgrp_time_from_event(struct perf_event *event)
600 struct perf_cgroup *cgrp;
603 * ensure we access cgroup data only when needed and
604 * when we know the cgroup is pinned (css_get)
606 if (!is_cgroup_event(event))
609 cgrp = perf_cgroup_from_task(current, event->ctx);
611 * Do not update time when cgroup is not active
613 if (cgrp == event->cgrp)
614 __update_cgrp_time(event->cgrp);
618 perf_cgroup_set_timestamp(struct task_struct *task,
619 struct perf_event_context *ctx)
621 struct perf_cgroup *cgrp;
622 struct perf_cgroup_info *info;
625 * ctx->lock held by caller
626 * ensure we do not access cgroup data
627 * unless we have the cgroup pinned (css_get)
629 if (!task || !ctx->nr_cgroups)
632 cgrp = perf_cgroup_from_task(task, ctx);
633 info = this_cpu_ptr(cgrp->info);
634 info->timestamp = ctx->timestamp;
637 #define PERF_CGROUP_SWOUT 0x1 /* cgroup switch out every event */
638 #define PERF_CGROUP_SWIN 0x2 /* cgroup switch in events based on task */
641 * reschedule events based on the cgroup constraint of task.
643 * mode SWOUT : schedule out everything
644 * mode SWIN : schedule in based on cgroup for next
646 static void perf_cgroup_switch(struct task_struct *task, int mode)
648 struct perf_cpu_context *cpuctx;
653 * disable interrupts to avoid geting nr_cgroup
654 * changes via __perf_event_disable(). Also
657 local_irq_save(flags);
660 * we reschedule only in the presence of cgroup
661 * constrained events.
664 list_for_each_entry_rcu(pmu, &pmus, entry) {
665 cpuctx = this_cpu_ptr(pmu->pmu_cpu_context);
666 if (cpuctx->unique_pmu != pmu)
667 continue; /* ensure we process each cpuctx once */
670 * perf_cgroup_events says at least one
671 * context on this CPU has cgroup events.
673 * ctx->nr_cgroups reports the number of cgroup
674 * events for a context.
676 if (cpuctx->ctx.nr_cgroups > 0) {
677 perf_ctx_lock(cpuctx, cpuctx->task_ctx);
678 perf_pmu_disable(cpuctx->ctx.pmu);
680 if (mode & PERF_CGROUP_SWOUT) {
681 cpu_ctx_sched_out(cpuctx, EVENT_ALL);
683 * must not be done before ctxswout due
684 * to event_filter_match() in event_sched_out()
689 if (mode & PERF_CGROUP_SWIN) {
690 WARN_ON_ONCE(cpuctx->cgrp);
692 * set cgrp before ctxsw in to allow
693 * event_filter_match() to not have to pass
695 * we pass the cpuctx->ctx to perf_cgroup_from_task()
696 * because cgorup events are only per-cpu
698 cpuctx->cgrp = perf_cgroup_from_task(task, &cpuctx->ctx);
699 cpu_ctx_sched_in(cpuctx, EVENT_ALL, task);
701 perf_pmu_enable(cpuctx->ctx.pmu);
702 perf_ctx_unlock(cpuctx, cpuctx->task_ctx);
706 local_irq_restore(flags);
709 static inline void perf_cgroup_sched_out(struct task_struct *task,
710 struct task_struct *next)
712 struct perf_cgroup *cgrp1;
713 struct perf_cgroup *cgrp2 = NULL;
717 * we come here when we know perf_cgroup_events > 0
718 * we do not need to pass the ctx here because we know
719 * we are holding the rcu lock
721 cgrp1 = perf_cgroup_from_task(task, NULL);
722 cgrp2 = perf_cgroup_from_task(next, NULL);
725 * only schedule out current cgroup events if we know
726 * that we are switching to a different cgroup. Otherwise,
727 * do no touch the cgroup events.
730 perf_cgroup_switch(task, PERF_CGROUP_SWOUT);
735 static inline void perf_cgroup_sched_in(struct task_struct *prev,
736 struct task_struct *task)
738 struct perf_cgroup *cgrp1;
739 struct perf_cgroup *cgrp2 = NULL;
743 * we come here when we know perf_cgroup_events > 0
744 * we do not need to pass the ctx here because we know
745 * we are holding the rcu lock
747 cgrp1 = perf_cgroup_from_task(task, NULL);
748 cgrp2 = perf_cgroup_from_task(prev, NULL);
751 * only need to schedule in cgroup events if we are changing
752 * cgroup during ctxsw. Cgroup events were not scheduled
753 * out of ctxsw out if that was not the case.
756 perf_cgroup_switch(task, PERF_CGROUP_SWIN);
761 static inline int perf_cgroup_connect(int fd, struct perf_event *event,
762 struct perf_event_attr *attr,
763 struct perf_event *group_leader)
765 struct perf_cgroup *cgrp;
766 struct cgroup_subsys_state *css;
767 struct fd f = fdget(fd);
773 css = css_tryget_online_from_dir(f.file->f_path.dentry,
774 &perf_event_cgrp_subsys);
780 cgrp = container_of(css, struct perf_cgroup, css);
784 * all events in a group must monitor
785 * the same cgroup because a task belongs
786 * to only one perf cgroup at a time
788 if (group_leader && group_leader->cgrp != cgrp) {
789 perf_detach_cgroup(event);
798 perf_cgroup_set_shadow_time(struct perf_event *event, u64 now)
800 struct perf_cgroup_info *t;
801 t = per_cpu_ptr(event->cgrp->info, event->cpu);
802 event->shadow_ctx_time = now - t->timestamp;
806 perf_cgroup_defer_enabled(struct perf_event *event)
809 * when the current task's perf cgroup does not match
810 * the event's, we need to remember to call the
811 * perf_mark_enable() function the first time a task with
812 * a matching perf cgroup is scheduled in.
814 if (is_cgroup_event(event) && !perf_cgroup_match(event))
815 event->cgrp_defer_enabled = 1;
819 perf_cgroup_mark_enabled(struct perf_event *event,
820 struct perf_event_context *ctx)
822 struct perf_event *sub;
823 u64 tstamp = perf_event_time(event);
825 if (!event->cgrp_defer_enabled)
828 event->cgrp_defer_enabled = 0;
830 event->tstamp_enabled = tstamp - event->total_time_enabled;
831 list_for_each_entry(sub, &event->sibling_list, group_entry) {
832 if (sub->state >= PERF_EVENT_STATE_INACTIVE) {
833 sub->tstamp_enabled = tstamp - sub->total_time_enabled;
834 sub->cgrp_defer_enabled = 0;
838 #else /* !CONFIG_CGROUP_PERF */
841 perf_cgroup_match(struct perf_event *event)
846 static inline void perf_detach_cgroup(struct perf_event *event)
849 static inline int is_cgroup_event(struct perf_event *event)
854 static inline u64 perf_cgroup_event_cgrp_time(struct perf_event *event)
859 static inline void update_cgrp_time_from_event(struct perf_event *event)
863 static inline void update_cgrp_time_from_cpuctx(struct perf_cpu_context *cpuctx)
867 static inline void perf_cgroup_sched_out(struct task_struct *task,
868 struct task_struct *next)
872 static inline void perf_cgroup_sched_in(struct task_struct *prev,
873 struct task_struct *task)
877 static inline int perf_cgroup_connect(pid_t pid, struct perf_event *event,
878 struct perf_event_attr *attr,
879 struct perf_event *group_leader)
885 perf_cgroup_set_timestamp(struct task_struct *task,
886 struct perf_event_context *ctx)
891 perf_cgroup_switch(struct task_struct *task, struct task_struct *next)
896 perf_cgroup_set_shadow_time(struct perf_event *event, u64 now)
900 static inline u64 perf_cgroup_event_time(struct perf_event *event)
906 perf_cgroup_defer_enabled(struct perf_event *event)
911 perf_cgroup_mark_enabled(struct perf_event *event,
912 struct perf_event_context *ctx)
918 * set default to be dependent on timer tick just
921 #define PERF_CPU_HRTIMER (1000 / HZ)
923 * function must be called with interrupts disbled
925 static enum hrtimer_restart perf_mux_hrtimer_handler(struct hrtimer *hr)
927 struct perf_cpu_context *cpuctx;
930 WARN_ON(!irqs_disabled());
932 cpuctx = container_of(hr, struct perf_cpu_context, hrtimer);
933 rotations = perf_rotate_context(cpuctx);
935 raw_spin_lock(&cpuctx->hrtimer_lock);
937 hrtimer_forward_now(hr, cpuctx->hrtimer_interval);
939 cpuctx->hrtimer_active = 0;
940 raw_spin_unlock(&cpuctx->hrtimer_lock);
942 return rotations ? HRTIMER_RESTART : HRTIMER_NORESTART;
945 static void __perf_mux_hrtimer_init(struct perf_cpu_context *cpuctx, int cpu)
947 struct hrtimer *timer = &cpuctx->hrtimer;
948 struct pmu *pmu = cpuctx->ctx.pmu;
951 /* no multiplexing needed for SW PMU */
952 if (pmu->task_ctx_nr == perf_sw_context)
956 * check default is sane, if not set then force to
957 * default interval (1/tick)
959 interval = pmu->hrtimer_interval_ms;
961 interval = pmu->hrtimer_interval_ms = PERF_CPU_HRTIMER;
963 cpuctx->hrtimer_interval = ns_to_ktime(NSEC_PER_MSEC * interval);
965 raw_spin_lock_init(&cpuctx->hrtimer_lock);
966 hrtimer_init(timer, CLOCK_MONOTONIC, HRTIMER_MODE_ABS_PINNED);
967 timer->function = perf_mux_hrtimer_handler;
970 static int perf_mux_hrtimer_restart(struct perf_cpu_context *cpuctx)
972 struct hrtimer *timer = &cpuctx->hrtimer;
973 struct pmu *pmu = cpuctx->ctx.pmu;
977 if (pmu->task_ctx_nr == perf_sw_context)
980 raw_spin_lock_irqsave(&cpuctx->hrtimer_lock, flags);
981 if (!cpuctx->hrtimer_active) {
982 cpuctx->hrtimer_active = 1;
983 hrtimer_forward_now(timer, cpuctx->hrtimer_interval);
984 hrtimer_start_expires(timer, HRTIMER_MODE_ABS_PINNED);
986 raw_spin_unlock_irqrestore(&cpuctx->hrtimer_lock, flags);
991 void perf_pmu_disable(struct pmu *pmu)
993 int *count = this_cpu_ptr(pmu->pmu_disable_count);
995 pmu->pmu_disable(pmu);
998 void perf_pmu_enable(struct pmu *pmu)
1000 int *count = this_cpu_ptr(pmu->pmu_disable_count);
1002 pmu->pmu_enable(pmu);
1005 static DEFINE_PER_CPU(struct list_head, active_ctx_list);
1008 * perf_event_ctx_activate(), perf_event_ctx_deactivate(), and
1009 * perf_event_task_tick() are fully serialized because they're strictly cpu
1010 * affine and perf_event_ctx{activate,deactivate} are called with IRQs
1011 * disabled, while perf_event_task_tick is called from IRQ context.
1013 static void perf_event_ctx_activate(struct perf_event_context *ctx)
1015 struct list_head *head = this_cpu_ptr(&active_ctx_list);
1017 WARN_ON(!irqs_disabled());
1019 WARN_ON(!list_empty(&ctx->active_ctx_list));
1021 list_add(&ctx->active_ctx_list, head);
1024 static void perf_event_ctx_deactivate(struct perf_event_context *ctx)
1026 WARN_ON(!irqs_disabled());
1028 WARN_ON(list_empty(&ctx->active_ctx_list));
1030 list_del_init(&ctx->active_ctx_list);
1033 static void get_ctx(struct perf_event_context *ctx)
1035 WARN_ON(!atomic_inc_not_zero(&ctx->refcount));
1038 static void free_ctx(struct rcu_head *head)
1040 struct perf_event_context *ctx;
1042 ctx = container_of(head, struct perf_event_context, rcu_head);
1043 kfree(ctx->task_ctx_data);
1047 static void put_ctx(struct perf_event_context *ctx)
1049 if (atomic_dec_and_test(&ctx->refcount)) {
1050 if (ctx->parent_ctx)
1051 put_ctx(ctx->parent_ctx);
1052 if (ctx->task && ctx->task != TASK_TOMBSTONE)
1053 put_task_struct(ctx->task);
1054 call_rcu(&ctx->rcu_head, free_ctx);
1059 * Because of perf_event::ctx migration in sys_perf_event_open::move_group and
1060 * perf_pmu_migrate_context() we need some magic.
1062 * Those places that change perf_event::ctx will hold both
1063 * perf_event_ctx::mutex of the 'old' and 'new' ctx value.
1065 * Lock ordering is by mutex address. There are two other sites where
1066 * perf_event_context::mutex nests and those are:
1068 * - perf_event_exit_task_context() [ child , 0 ]
1069 * perf_event_exit_event()
1070 * put_event() [ parent, 1 ]
1072 * - perf_event_init_context() [ parent, 0 ]
1073 * inherit_task_group()
1076 * perf_event_alloc()
1078 * perf_try_init_event() [ child , 1 ]
1080 * While it appears there is an obvious deadlock here -- the parent and child
1081 * nesting levels are inverted between the two. This is in fact safe because
1082 * life-time rules separate them. That is an exiting task cannot fork, and a
1083 * spawning task cannot (yet) exit.
1085 * But remember that that these are parent<->child context relations, and
1086 * migration does not affect children, therefore these two orderings should not
1089 * The change in perf_event::ctx does not affect children (as claimed above)
1090 * because the sys_perf_event_open() case will install a new event and break
1091 * the ctx parent<->child relation, and perf_pmu_migrate_context() is only
1092 * concerned with cpuctx and that doesn't have children.
1094 * The places that change perf_event::ctx will issue:
1096 * perf_remove_from_context();
1097 * synchronize_rcu();
1098 * perf_install_in_context();
1100 * to affect the change. The remove_from_context() + synchronize_rcu() should
1101 * quiesce the event, after which we can install it in the new location. This
1102 * means that only external vectors (perf_fops, prctl) can perturb the event
1103 * while in transit. Therefore all such accessors should also acquire
1104 * perf_event_context::mutex to serialize against this.
1106 * However; because event->ctx can change while we're waiting to acquire
1107 * ctx->mutex we must be careful and use the below perf_event_ctx_lock()
1112 * task_struct::perf_event_mutex
1113 * perf_event_context::mutex
1114 * perf_event::child_mutex;
1115 * perf_event_context::lock
1116 * perf_event::mmap_mutex
1119 static struct perf_event_context *
1120 perf_event_ctx_lock_nested(struct perf_event *event, int nesting)
1122 struct perf_event_context *ctx;
1126 ctx = ACCESS_ONCE(event->ctx);
1127 if (!atomic_inc_not_zero(&ctx->refcount)) {
1133 mutex_lock_nested(&ctx->mutex, nesting);
1134 if (event->ctx != ctx) {
1135 mutex_unlock(&ctx->mutex);
1143 static inline struct perf_event_context *
1144 perf_event_ctx_lock(struct perf_event *event)
1146 return perf_event_ctx_lock_nested(event, 0);
1149 static void perf_event_ctx_unlock(struct perf_event *event,
1150 struct perf_event_context *ctx)
1152 mutex_unlock(&ctx->mutex);
1157 * This must be done under the ctx->lock, such as to serialize against
1158 * context_equiv(), therefore we cannot call put_ctx() since that might end up
1159 * calling scheduler related locks and ctx->lock nests inside those.
1161 static __must_check struct perf_event_context *
1162 unclone_ctx(struct perf_event_context *ctx)
1164 struct perf_event_context *parent_ctx = ctx->parent_ctx;
1166 lockdep_assert_held(&ctx->lock);
1169 ctx->parent_ctx = NULL;
1175 static u32 perf_event_pid(struct perf_event *event, struct task_struct *p)
1178 * only top level events have the pid namespace they were created in
1181 event = event->parent;
1183 return task_tgid_nr_ns(p, event->ns);
1186 static u32 perf_event_tid(struct perf_event *event, struct task_struct *p)
1189 * only top level events have the pid namespace they were created in
1192 event = event->parent;
1194 return task_pid_nr_ns(p, event->ns);
1198 * If we inherit events we want to return the parent event id
1201 static u64 primary_event_id(struct perf_event *event)
1206 id = event->parent->id;
1212 * Get the perf_event_context for a task and lock it.
1214 * This has to cope with with the fact that until it is locked,
1215 * the context could get moved to another task.
1217 static struct perf_event_context *
1218 perf_lock_task_context(struct task_struct *task, int ctxn, unsigned long *flags)
1220 struct perf_event_context *ctx;
1224 * One of the few rules of preemptible RCU is that one cannot do
1225 * rcu_read_unlock() while holding a scheduler (or nested) lock when
1226 * part of the read side critical section was irqs-enabled -- see
1227 * rcu_read_unlock_special().
1229 * Since ctx->lock nests under rq->lock we must ensure the entire read
1230 * side critical section has interrupts disabled.
1232 local_irq_save(*flags);
1234 ctx = rcu_dereference(task->perf_event_ctxp[ctxn]);
1237 * If this context is a clone of another, it might
1238 * get swapped for another underneath us by
1239 * perf_event_task_sched_out, though the
1240 * rcu_read_lock() protects us from any context
1241 * getting freed. Lock the context and check if it
1242 * got swapped before we could get the lock, and retry
1243 * if so. If we locked the right context, then it
1244 * can't get swapped on us any more.
1246 raw_spin_lock(&ctx->lock);
1247 if (ctx != rcu_dereference(task->perf_event_ctxp[ctxn])) {
1248 raw_spin_unlock(&ctx->lock);
1250 local_irq_restore(*flags);
1254 if (ctx->task == TASK_TOMBSTONE ||
1255 !atomic_inc_not_zero(&ctx->refcount)) {
1256 raw_spin_unlock(&ctx->lock);
1259 WARN_ON_ONCE(ctx->task != task);
1264 local_irq_restore(*flags);
1269 * Get the context for a task and increment its pin_count so it
1270 * can't get swapped to another task. This also increments its
1271 * reference count so that the context can't get freed.
1273 static struct perf_event_context *
1274 perf_pin_task_context(struct task_struct *task, int ctxn)
1276 struct perf_event_context *ctx;
1277 unsigned long flags;
1279 ctx = perf_lock_task_context(task, ctxn, &flags);
1282 raw_spin_unlock_irqrestore(&ctx->lock, flags);
1287 static void perf_unpin_context(struct perf_event_context *ctx)
1289 unsigned long flags;
1291 raw_spin_lock_irqsave(&ctx->lock, flags);
1293 raw_spin_unlock_irqrestore(&ctx->lock, flags);
1297 * Update the record of the current time in a context.
1299 static void update_context_time(struct perf_event_context *ctx)
1301 u64 now = perf_clock();
1303 ctx->time += now - ctx->timestamp;
1304 ctx->timestamp = now;
1307 static u64 perf_event_time(struct perf_event *event)
1309 struct perf_event_context *ctx = event->ctx;
1311 if (is_cgroup_event(event))
1312 return perf_cgroup_event_time(event);
1314 return ctx ? ctx->time : 0;
1318 * Update the total_time_enabled and total_time_running fields for a event.
1320 static void update_event_times(struct perf_event *event)
1322 struct perf_event_context *ctx = event->ctx;
1325 lockdep_assert_held(&ctx->lock);
1327 if (event->state < PERF_EVENT_STATE_INACTIVE ||
1328 event->group_leader->state < PERF_EVENT_STATE_INACTIVE)
1332 * in cgroup mode, time_enabled represents
1333 * the time the event was enabled AND active
1334 * tasks were in the monitored cgroup. This is
1335 * independent of the activity of the context as
1336 * there may be a mix of cgroup and non-cgroup events.
1338 * That is why we treat cgroup events differently
1341 if (is_cgroup_event(event))
1342 run_end = perf_cgroup_event_time(event);
1343 else if (ctx->is_active)
1344 run_end = ctx->time;
1346 run_end = event->tstamp_stopped;
1348 event->total_time_enabled = run_end - event->tstamp_enabled;
1350 if (event->state == PERF_EVENT_STATE_INACTIVE)
1351 run_end = event->tstamp_stopped;
1353 run_end = perf_event_time(event);
1355 event->total_time_running = run_end - event->tstamp_running;
1360 * Update total_time_enabled and total_time_running for all events in a group.
1362 static void update_group_times(struct perf_event *leader)
1364 struct perf_event *event;
1366 update_event_times(leader);
1367 list_for_each_entry(event, &leader->sibling_list, group_entry)
1368 update_event_times(event);
1371 static struct list_head *
1372 ctx_group_list(struct perf_event *event, struct perf_event_context *ctx)
1374 if (event->attr.pinned)
1375 return &ctx->pinned_groups;
1377 return &ctx->flexible_groups;
1381 * Add a event from the lists for its context.
1382 * Must be called with ctx->mutex and ctx->lock held.
1385 list_add_event(struct perf_event *event, struct perf_event_context *ctx)
1387 lockdep_assert_held(&ctx->lock);
1389 WARN_ON_ONCE(event->attach_state & PERF_ATTACH_CONTEXT);
1390 event->attach_state |= PERF_ATTACH_CONTEXT;
1393 * If we're a stand alone event or group leader, we go to the context
1394 * list, group events are kept attached to the group so that
1395 * perf_group_detach can, at all times, locate all siblings.
1397 if (event->group_leader == event) {
1398 struct list_head *list;
1400 if (is_software_event(event))
1401 event->group_flags |= PERF_GROUP_SOFTWARE;
1403 list = ctx_group_list(event, ctx);
1404 list_add_tail(&event->group_entry, list);
1407 if (is_cgroup_event(event))
1410 list_add_rcu(&event->event_entry, &ctx->event_list);
1412 if (event->attr.inherit_stat)
1419 * Initialize event state based on the perf_event_attr::disabled.
1421 static inline void perf_event__state_init(struct perf_event *event)
1423 event->state = event->attr.disabled ? PERF_EVENT_STATE_OFF :
1424 PERF_EVENT_STATE_INACTIVE;
1427 static void __perf_event_read_size(struct perf_event *event, int nr_siblings)
1429 int entry = sizeof(u64); /* value */
1433 if (event->attr.read_format & PERF_FORMAT_TOTAL_TIME_ENABLED)
1434 size += sizeof(u64);
1436 if (event->attr.read_format & PERF_FORMAT_TOTAL_TIME_RUNNING)
1437 size += sizeof(u64);
1439 if (event->attr.read_format & PERF_FORMAT_ID)
1440 entry += sizeof(u64);
1442 if (event->attr.read_format & PERF_FORMAT_GROUP) {
1444 size += sizeof(u64);
1448 event->read_size = size;
1451 static void __perf_event_header_size(struct perf_event *event, u64 sample_type)
1453 struct perf_sample_data *data;
1456 if (sample_type & PERF_SAMPLE_IP)
1457 size += sizeof(data->ip);
1459 if (sample_type & PERF_SAMPLE_ADDR)
1460 size += sizeof(data->addr);
1462 if (sample_type & PERF_SAMPLE_PERIOD)
1463 size += sizeof(data->period);
1465 if (sample_type & PERF_SAMPLE_WEIGHT)
1466 size += sizeof(data->weight);
1468 if (sample_type & PERF_SAMPLE_READ)
1469 size += event->read_size;
1471 if (sample_type & PERF_SAMPLE_DATA_SRC)
1472 size += sizeof(data->data_src.val);
1474 if (sample_type & PERF_SAMPLE_TRANSACTION)
1475 size += sizeof(data->txn);
1477 event->header_size = size;
1481 * Called at perf_event creation and when events are attached/detached from a
1484 static void perf_event__header_size(struct perf_event *event)
1486 __perf_event_read_size(event,
1487 event->group_leader->nr_siblings);
1488 __perf_event_header_size(event, event->attr.sample_type);
1491 static void perf_event__id_header_size(struct perf_event *event)
1493 struct perf_sample_data *data;
1494 u64 sample_type = event->attr.sample_type;
1497 if (sample_type & PERF_SAMPLE_TID)
1498 size += sizeof(data->tid_entry);
1500 if (sample_type & PERF_SAMPLE_TIME)
1501 size += sizeof(data->time);
1503 if (sample_type & PERF_SAMPLE_IDENTIFIER)
1504 size += sizeof(data->id);
1506 if (sample_type & PERF_SAMPLE_ID)
1507 size += sizeof(data->id);
1509 if (sample_type & PERF_SAMPLE_STREAM_ID)
1510 size += sizeof(data->stream_id);
1512 if (sample_type & PERF_SAMPLE_CPU)
1513 size += sizeof(data->cpu_entry);
1515 event->id_header_size = size;
1518 static bool perf_event_validate_size(struct perf_event *event)
1521 * The values computed here will be over-written when we actually
1524 __perf_event_read_size(event, event->group_leader->nr_siblings + 1);
1525 __perf_event_header_size(event, event->attr.sample_type & ~PERF_SAMPLE_READ);
1526 perf_event__id_header_size(event);
1529 * Sum the lot; should not exceed the 64k limit we have on records.
1530 * Conservative limit to allow for callchains and other variable fields.
1532 if (event->read_size + event->header_size +
1533 event->id_header_size + sizeof(struct perf_event_header) >= 16*1024)
1539 static void perf_group_attach(struct perf_event *event)
1541 struct perf_event *group_leader = event->group_leader, *pos;
1544 * We can have double attach due to group movement in perf_event_open.
1546 if (event->attach_state & PERF_ATTACH_GROUP)
1549 event->attach_state |= PERF_ATTACH_GROUP;
1551 if (group_leader == event)
1554 WARN_ON_ONCE(group_leader->ctx != event->ctx);
1556 if (group_leader->group_flags & PERF_GROUP_SOFTWARE &&
1557 !is_software_event(event))
1558 group_leader->group_flags &= ~PERF_GROUP_SOFTWARE;
1560 list_add_tail(&event->group_entry, &group_leader->sibling_list);
1561 group_leader->nr_siblings++;
1563 perf_event__header_size(group_leader);
1565 list_for_each_entry(pos, &group_leader->sibling_list, group_entry)
1566 perf_event__header_size(pos);
1570 * Remove a event from the lists for its context.
1571 * Must be called with ctx->mutex and ctx->lock held.
1574 list_del_event(struct perf_event *event, struct perf_event_context *ctx)
1576 struct perf_cpu_context *cpuctx;
1578 WARN_ON_ONCE(event->ctx != ctx);
1579 lockdep_assert_held(&ctx->lock);
1582 * We can have double detach due to exit/hot-unplug + close.
1584 if (!(event->attach_state & PERF_ATTACH_CONTEXT))
1587 event->attach_state &= ~PERF_ATTACH_CONTEXT;
1589 if (is_cgroup_event(event)) {
1592 * Because cgroup events are always per-cpu events, this will
1593 * always be called from the right CPU.
1595 cpuctx = __get_cpu_context(ctx);
1597 * If there are no more cgroup events then clear cgrp to avoid
1598 * stale pointer in update_cgrp_time_from_cpuctx().
1600 if (!ctx->nr_cgroups)
1601 cpuctx->cgrp = NULL;
1605 if (event->attr.inherit_stat)
1608 list_del_rcu(&event->event_entry);
1610 if (event->group_leader == event)
1611 list_del_init(&event->group_entry);
1613 update_group_times(event);
1616 * If event was in error state, then keep it
1617 * that way, otherwise bogus counts will be
1618 * returned on read(). The only way to get out
1619 * of error state is by explicit re-enabling
1622 if (event->state > PERF_EVENT_STATE_OFF)
1623 event->state = PERF_EVENT_STATE_OFF;
1628 static void perf_group_detach(struct perf_event *event)
1630 struct perf_event *sibling, *tmp;
1631 struct list_head *list = NULL;
1634 * We can have double detach due to exit/hot-unplug + close.
1636 if (!(event->attach_state & PERF_ATTACH_GROUP))
1639 event->attach_state &= ~PERF_ATTACH_GROUP;
1642 * If this is a sibling, remove it from its group.
1644 if (event->group_leader != event) {
1645 list_del_init(&event->group_entry);
1646 event->group_leader->nr_siblings--;
1650 if (!list_empty(&event->group_entry))
1651 list = &event->group_entry;
1654 * If this was a group event with sibling events then
1655 * upgrade the siblings to singleton events by adding them
1656 * to whatever list we are on.
1658 list_for_each_entry_safe(sibling, tmp, &event->sibling_list, group_entry) {
1660 list_move_tail(&sibling->group_entry, list);
1661 sibling->group_leader = sibling;
1663 /* Inherit group flags from the previous leader */
1664 sibling->group_flags = event->group_flags;
1666 WARN_ON_ONCE(sibling->ctx != event->ctx);
1670 perf_event__header_size(event->group_leader);
1672 list_for_each_entry(tmp, &event->group_leader->sibling_list, group_entry)
1673 perf_event__header_size(tmp);
1676 static bool is_orphaned_event(struct perf_event *event)
1678 return event->state == PERF_EVENT_STATE_DEAD;
1681 static inline int pmu_filter_match(struct perf_event *event)
1683 struct pmu *pmu = event->pmu;
1684 return pmu->filter_match ? pmu->filter_match(event) : 1;
1688 event_filter_match(struct perf_event *event)
1690 return (event->cpu == -1 || event->cpu == smp_processor_id())
1691 && perf_cgroup_match(event) && pmu_filter_match(event);
1695 event_sched_out(struct perf_event *event,
1696 struct perf_cpu_context *cpuctx,
1697 struct perf_event_context *ctx)
1699 u64 tstamp = perf_event_time(event);
1702 WARN_ON_ONCE(event->ctx != ctx);
1703 lockdep_assert_held(&ctx->lock);
1706 * An event which could not be activated because of
1707 * filter mismatch still needs to have its timings
1708 * maintained, otherwise bogus information is return
1709 * via read() for time_enabled, time_running:
1711 if (event->state == PERF_EVENT_STATE_INACTIVE
1712 && !event_filter_match(event)) {
1713 delta = tstamp - event->tstamp_stopped;
1714 event->tstamp_running += delta;
1715 event->tstamp_stopped = tstamp;
1718 if (event->state != PERF_EVENT_STATE_ACTIVE)
1721 perf_pmu_disable(event->pmu);
1723 event->tstamp_stopped = tstamp;
1724 event->pmu->del(event, 0);
1726 event->state = PERF_EVENT_STATE_INACTIVE;
1727 if (event->pending_disable) {
1728 event->pending_disable = 0;
1729 event->state = PERF_EVENT_STATE_OFF;
1732 if (!is_software_event(event))
1733 cpuctx->active_oncpu--;
1734 if (!--ctx->nr_active)
1735 perf_event_ctx_deactivate(ctx);
1736 if (event->attr.freq && event->attr.sample_freq)
1738 if (event->attr.exclusive || !cpuctx->active_oncpu)
1739 cpuctx->exclusive = 0;
1741 perf_pmu_enable(event->pmu);
1745 group_sched_out(struct perf_event *group_event,
1746 struct perf_cpu_context *cpuctx,
1747 struct perf_event_context *ctx)
1749 struct perf_event *event;
1750 int state = group_event->state;
1752 event_sched_out(group_event, cpuctx, ctx);
1755 * Schedule out siblings (if any):
1757 list_for_each_entry(event, &group_event->sibling_list, group_entry)
1758 event_sched_out(event, cpuctx, ctx);
1760 if (state == PERF_EVENT_STATE_ACTIVE && group_event->attr.exclusive)
1761 cpuctx->exclusive = 0;
1764 #define DETACH_GROUP 0x01UL
1767 * Cross CPU call to remove a performance event
1769 * We disable the event on the hardware level first. After that we
1770 * remove it from the context list.
1773 __perf_remove_from_context(struct perf_event *event,
1774 struct perf_cpu_context *cpuctx,
1775 struct perf_event_context *ctx,
1778 unsigned long flags = (unsigned long)info;
1780 event_sched_out(event, cpuctx, ctx);
1781 if (flags & DETACH_GROUP)
1782 perf_group_detach(event);
1783 list_del_event(event, ctx);
1785 if (!ctx->nr_events && ctx->is_active) {
1788 WARN_ON_ONCE(cpuctx->task_ctx != ctx);
1789 cpuctx->task_ctx = NULL;
1795 * Remove the event from a task's (or a CPU's) list of events.
1797 * If event->ctx is a cloned context, callers must make sure that
1798 * every task struct that event->ctx->task could possibly point to
1799 * remains valid. This is OK when called from perf_release since
1800 * that only calls us on the top-level context, which can't be a clone.
1801 * When called from perf_event_exit_task, it's OK because the
1802 * context has been detached from its task.
1804 static void perf_remove_from_context(struct perf_event *event, unsigned long flags)
1806 lockdep_assert_held(&event->ctx->mutex);
1808 event_function_call(event, __perf_remove_from_context, (void *)flags);
1812 * Cross CPU call to disable a performance event
1814 static void __perf_event_disable(struct perf_event *event,
1815 struct perf_cpu_context *cpuctx,
1816 struct perf_event_context *ctx,
1819 if (event->state < PERF_EVENT_STATE_INACTIVE)
1822 update_context_time(ctx);
1823 update_cgrp_time_from_event(event);
1824 update_group_times(event);
1825 if (event == event->group_leader)
1826 group_sched_out(event, cpuctx, ctx);
1828 event_sched_out(event, cpuctx, ctx);
1829 event->state = PERF_EVENT_STATE_OFF;
1835 * If event->ctx is a cloned context, callers must make sure that
1836 * every task struct that event->ctx->task could possibly point to
1837 * remains valid. This condition is satisifed when called through
1838 * perf_event_for_each_child or perf_event_for_each because they
1839 * hold the top-level event's child_mutex, so any descendant that
1840 * goes to exit will block in perf_event_exit_event().
1842 * When called from perf_pending_event it's OK because event->ctx
1843 * is the current context on this CPU and preemption is disabled,
1844 * hence we can't get into perf_event_task_sched_out for this context.
1846 static void _perf_event_disable(struct perf_event *event)
1848 struct perf_event_context *ctx = event->ctx;
1850 raw_spin_lock_irq(&ctx->lock);
1851 if (event->state <= PERF_EVENT_STATE_OFF) {
1852 raw_spin_unlock_irq(&ctx->lock);
1855 raw_spin_unlock_irq(&ctx->lock);
1857 event_function_call(event, __perf_event_disable, NULL);
1860 void perf_event_disable_local(struct perf_event *event)
1862 event_function_local(event, __perf_event_disable, NULL);
1866 * Strictly speaking kernel users cannot create groups and therefore this
1867 * interface does not need the perf_event_ctx_lock() magic.
1869 void perf_event_disable(struct perf_event *event)
1871 struct perf_event_context *ctx;
1873 ctx = perf_event_ctx_lock(event);
1874 _perf_event_disable(event);
1875 perf_event_ctx_unlock(event, ctx);
1877 EXPORT_SYMBOL_GPL(perf_event_disable);
1879 static void perf_set_shadow_time(struct perf_event *event,
1880 struct perf_event_context *ctx,
1884 * use the correct time source for the time snapshot
1886 * We could get by without this by leveraging the
1887 * fact that to get to this function, the caller
1888 * has most likely already called update_context_time()
1889 * and update_cgrp_time_xx() and thus both timestamp
1890 * are identical (or very close). Given that tstamp is,
1891 * already adjusted for cgroup, we could say that:
1892 * tstamp - ctx->timestamp
1894 * tstamp - cgrp->timestamp.
1896 * Then, in perf_output_read(), the calculation would
1897 * work with no changes because:
1898 * - event is guaranteed scheduled in
1899 * - no scheduled out in between
1900 * - thus the timestamp would be the same
1902 * But this is a bit hairy.
1904 * So instead, we have an explicit cgroup call to remain
1905 * within the time time source all along. We believe it
1906 * is cleaner and simpler to understand.
1908 if (is_cgroup_event(event))
1909 perf_cgroup_set_shadow_time(event, tstamp);
1911 event->shadow_ctx_time = tstamp - ctx->timestamp;
1914 #define MAX_INTERRUPTS (~0ULL)
1916 static void perf_log_throttle(struct perf_event *event, int enable);
1917 static void perf_log_itrace_start(struct perf_event *event);
1920 event_sched_in(struct perf_event *event,
1921 struct perf_cpu_context *cpuctx,
1922 struct perf_event_context *ctx)
1924 u64 tstamp = perf_event_time(event);
1927 lockdep_assert_held(&ctx->lock);
1929 if (event->state <= PERF_EVENT_STATE_OFF)
1932 WRITE_ONCE(event->oncpu, smp_processor_id());
1934 * Order event::oncpu write to happen before the ACTIVE state
1938 WRITE_ONCE(event->state, PERF_EVENT_STATE_ACTIVE);
1941 * Unthrottle events, since we scheduled we might have missed several
1942 * ticks already, also for a heavily scheduling task there is little
1943 * guarantee it'll get a tick in a timely manner.
1945 if (unlikely(event->hw.interrupts == MAX_INTERRUPTS)) {
1946 perf_log_throttle(event, 1);
1947 event->hw.interrupts = 0;
1951 * The new state must be visible before we turn it on in the hardware:
1955 perf_pmu_disable(event->pmu);
1957 perf_set_shadow_time(event, ctx, tstamp);
1959 perf_log_itrace_start(event);
1961 if (event->pmu->add(event, PERF_EF_START)) {
1962 event->state = PERF_EVENT_STATE_INACTIVE;
1968 event->tstamp_running += tstamp - event->tstamp_stopped;
1970 if (!is_software_event(event))
1971 cpuctx->active_oncpu++;
1972 if (!ctx->nr_active++)
1973 perf_event_ctx_activate(ctx);
1974 if (event->attr.freq && event->attr.sample_freq)
1977 if (event->attr.exclusive)
1978 cpuctx->exclusive = 1;
1981 perf_pmu_enable(event->pmu);
1987 group_sched_in(struct perf_event *group_event,
1988 struct perf_cpu_context *cpuctx,
1989 struct perf_event_context *ctx)
1991 struct perf_event *event, *partial_group = NULL;
1992 struct pmu *pmu = ctx->pmu;
1993 u64 now = ctx->time;
1994 bool simulate = false;
1996 if (group_event->state == PERF_EVENT_STATE_OFF)
1999 pmu->start_txn(pmu, PERF_PMU_TXN_ADD);
2001 if (event_sched_in(group_event, cpuctx, ctx)) {
2002 pmu->cancel_txn(pmu);
2003 perf_mux_hrtimer_restart(cpuctx);
2008 * Schedule in siblings as one group (if any):
2010 list_for_each_entry(event, &group_event->sibling_list, group_entry) {
2011 if (event_sched_in(event, cpuctx, ctx)) {
2012 partial_group = event;
2017 if (!pmu->commit_txn(pmu))
2022 * Groups can be scheduled in as one unit only, so undo any
2023 * partial group before returning:
2024 * The events up to the failed event are scheduled out normally,
2025 * tstamp_stopped will be updated.
2027 * The failed events and the remaining siblings need to have
2028 * their timings updated as if they had gone thru event_sched_in()
2029 * and event_sched_out(). This is required to get consistent timings
2030 * across the group. This also takes care of the case where the group
2031 * could never be scheduled by ensuring tstamp_stopped is set to mark
2032 * the time the event was actually stopped, such that time delta
2033 * calculation in update_event_times() is correct.
2035 list_for_each_entry(event, &group_event->sibling_list, group_entry) {
2036 if (event == partial_group)
2040 event->tstamp_running += now - event->tstamp_stopped;
2041 event->tstamp_stopped = now;
2043 event_sched_out(event, cpuctx, ctx);
2046 event_sched_out(group_event, cpuctx, ctx);
2048 pmu->cancel_txn(pmu);
2050 perf_mux_hrtimer_restart(cpuctx);
2056 * Work out whether we can put this event group on the CPU now.
2058 static int group_can_go_on(struct perf_event *event,
2059 struct perf_cpu_context *cpuctx,
2063 * Groups consisting entirely of software events can always go on.
2065 if (event->group_flags & PERF_GROUP_SOFTWARE)
2068 * If an exclusive group is already on, no other hardware
2071 if (cpuctx->exclusive)
2074 * If this group is exclusive and there are already
2075 * events on the CPU, it can't go on.
2077 if (event->attr.exclusive && cpuctx->active_oncpu)
2080 * Otherwise, try to add it if all previous groups were able
2086 static void add_event_to_ctx(struct perf_event *event,
2087 struct perf_event_context *ctx)
2089 u64 tstamp = perf_event_time(event);
2091 list_add_event(event, ctx);
2092 perf_group_attach(event);
2093 event->tstamp_enabled = tstamp;
2094 event->tstamp_running = tstamp;
2095 event->tstamp_stopped = tstamp;
2098 static void ctx_sched_out(struct perf_event_context *ctx,
2099 struct perf_cpu_context *cpuctx,
2100 enum event_type_t event_type);
2102 ctx_sched_in(struct perf_event_context *ctx,
2103 struct perf_cpu_context *cpuctx,
2104 enum event_type_t event_type,
2105 struct task_struct *task);
2107 static void task_ctx_sched_out(struct perf_cpu_context *cpuctx,
2108 struct perf_event_context *ctx)
2110 if (!cpuctx->task_ctx)
2113 if (WARN_ON_ONCE(ctx != cpuctx->task_ctx))
2116 ctx_sched_out(ctx, cpuctx, EVENT_ALL);
2119 static void perf_event_sched_in(struct perf_cpu_context *cpuctx,
2120 struct perf_event_context *ctx,
2121 struct task_struct *task)
2123 cpu_ctx_sched_in(cpuctx, EVENT_PINNED, task);
2125 ctx_sched_in(ctx, cpuctx, EVENT_PINNED, task);
2126 cpu_ctx_sched_in(cpuctx, EVENT_FLEXIBLE, task);
2128 ctx_sched_in(ctx, cpuctx, EVENT_FLEXIBLE, task);
2131 static void ctx_resched(struct perf_cpu_context *cpuctx,
2132 struct perf_event_context *task_ctx)
2134 perf_pmu_disable(cpuctx->ctx.pmu);
2136 task_ctx_sched_out(cpuctx, task_ctx);
2137 cpu_ctx_sched_out(cpuctx, EVENT_ALL);
2138 perf_event_sched_in(cpuctx, task_ctx, current);
2139 perf_pmu_enable(cpuctx->ctx.pmu);
2143 * Cross CPU call to install and enable a performance event
2145 * Very similar to remote_function() + event_function() but cannot assume that
2146 * things like ctx->is_active and cpuctx->task_ctx are set.
2148 static int __perf_install_in_context(void *info)
2150 struct perf_event *event = info;
2151 struct perf_event_context *ctx = event->ctx;
2152 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
2153 struct perf_event_context *task_ctx = cpuctx->task_ctx;
2154 bool activate = true;
2157 raw_spin_lock(&cpuctx->ctx.lock);
2159 raw_spin_lock(&ctx->lock);
2162 /* If we're on the wrong CPU, try again */
2163 if (task_cpu(ctx->task) != smp_processor_id()) {
2169 * If we're on the right CPU, see if the task we target is
2170 * current, if not we don't have to activate the ctx, a future
2171 * context switch will do that for us.
2173 if (ctx->task != current)
2176 WARN_ON_ONCE(cpuctx->task_ctx && cpuctx->task_ctx != ctx);
2178 } else if (task_ctx) {
2179 raw_spin_lock(&task_ctx->lock);
2183 ctx_sched_out(ctx, cpuctx, EVENT_TIME);
2184 add_event_to_ctx(event, ctx);
2185 ctx_resched(cpuctx, task_ctx);
2187 add_event_to_ctx(event, ctx);
2191 perf_ctx_unlock(cpuctx, task_ctx);
2197 * Attach a performance event to a context.
2199 * Very similar to event_function_call, see comment there.
2202 perf_install_in_context(struct perf_event_context *ctx,
2203 struct perf_event *event,
2206 struct task_struct *task = READ_ONCE(ctx->task);
2208 lockdep_assert_held(&ctx->mutex);
2211 if (event->cpu != -1)
2215 cpu_function_call(cpu, __perf_install_in_context, event);
2220 * Should not happen, we validate the ctx is still alive before calling.
2222 if (WARN_ON_ONCE(task == TASK_TOMBSTONE))
2226 * Installing events is tricky because we cannot rely on ctx->is_active
2227 * to be set in case this is the nr_events 0 -> 1 transition.
2231 * Cannot use task_function_call() because we need to run on the task's
2232 * CPU regardless of whether its current or not.
2234 if (!cpu_function_call(task_cpu(task), __perf_install_in_context, event))
2237 raw_spin_lock_irq(&ctx->lock);
2239 if (WARN_ON_ONCE(task == TASK_TOMBSTONE)) {
2241 * Cannot happen because we already checked above (which also
2242 * cannot happen), and we hold ctx->mutex, which serializes us
2243 * against perf_event_exit_task_context().
2245 raw_spin_unlock_irq(&ctx->lock);
2248 raw_spin_unlock_irq(&ctx->lock);
2250 * Since !ctx->is_active doesn't mean anything, we must IPI
2257 * Put a event into inactive state and update time fields.
2258 * Enabling the leader of a group effectively enables all
2259 * the group members that aren't explicitly disabled, so we
2260 * have to update their ->tstamp_enabled also.
2261 * Note: this works for group members as well as group leaders
2262 * since the non-leader members' sibling_lists will be empty.
2264 static void __perf_event_mark_enabled(struct perf_event *event)
2266 struct perf_event *sub;
2267 u64 tstamp = perf_event_time(event);
2269 event->state = PERF_EVENT_STATE_INACTIVE;
2270 event->tstamp_enabled = tstamp - event->total_time_enabled;
2271 list_for_each_entry(sub, &event->sibling_list, group_entry) {
2272 if (sub->state >= PERF_EVENT_STATE_INACTIVE)
2273 sub->tstamp_enabled = tstamp - sub->total_time_enabled;
2278 * Cross CPU call to enable a performance event
2280 static void __perf_event_enable(struct perf_event *event,
2281 struct perf_cpu_context *cpuctx,
2282 struct perf_event_context *ctx,
2285 struct perf_event *leader = event->group_leader;
2286 struct perf_event_context *task_ctx;
2288 if (event->state >= PERF_EVENT_STATE_INACTIVE ||
2289 event->state <= PERF_EVENT_STATE_ERROR)
2293 ctx_sched_out(ctx, cpuctx, EVENT_TIME);
2295 __perf_event_mark_enabled(event);
2297 if (!ctx->is_active)
2300 if (!event_filter_match(event)) {
2301 if (is_cgroup_event(event))
2302 perf_cgroup_defer_enabled(event);
2303 ctx_sched_in(ctx, cpuctx, EVENT_TIME, current);
2308 * If the event is in a group and isn't the group leader,
2309 * then don't put it on unless the group is on.
2311 if (leader != event && leader->state != PERF_EVENT_STATE_ACTIVE) {
2312 ctx_sched_in(ctx, cpuctx, EVENT_TIME, current);
2316 task_ctx = cpuctx->task_ctx;
2318 WARN_ON_ONCE(task_ctx != ctx);
2320 ctx_resched(cpuctx, task_ctx);
2326 * If event->ctx is a cloned context, callers must make sure that
2327 * every task struct that event->ctx->task could possibly point to
2328 * remains valid. This condition is satisfied when called through
2329 * perf_event_for_each_child or perf_event_for_each as described
2330 * for perf_event_disable.
2332 static void _perf_event_enable(struct perf_event *event)
2334 struct perf_event_context *ctx = event->ctx;
2336 raw_spin_lock_irq(&ctx->lock);
2337 if (event->state >= PERF_EVENT_STATE_INACTIVE ||
2338 event->state < PERF_EVENT_STATE_ERROR) {
2339 raw_spin_unlock_irq(&ctx->lock);
2344 * If the event is in error state, clear that first.
2346 * That way, if we see the event in error state below, we know that it
2347 * has gone back into error state, as distinct from the task having
2348 * been scheduled away before the cross-call arrived.
2350 if (event->state == PERF_EVENT_STATE_ERROR)
2351 event->state = PERF_EVENT_STATE_OFF;
2352 raw_spin_unlock_irq(&ctx->lock);
2354 event_function_call(event, __perf_event_enable, NULL);
2358 * See perf_event_disable();
2360 void perf_event_enable(struct perf_event *event)
2362 struct perf_event_context *ctx;
2364 ctx = perf_event_ctx_lock(event);
2365 _perf_event_enable(event);
2366 perf_event_ctx_unlock(event, ctx);
2368 EXPORT_SYMBOL_GPL(perf_event_enable);
2370 struct stop_event_data {
2371 struct perf_event *event;
2372 unsigned int restart;
2375 static int __perf_event_stop(void *info)
2377 struct stop_event_data *sd = info;
2378 struct perf_event *event = sd->event;
2380 /* if it's already INACTIVE, do nothing */
2381 if (READ_ONCE(event->state) != PERF_EVENT_STATE_ACTIVE)
2384 /* matches smp_wmb() in event_sched_in() */
2388 * There is a window with interrupts enabled before we get here,
2389 * so we need to check again lest we try to stop another CPU's event.
2391 if (READ_ONCE(event->oncpu) != smp_processor_id())
2394 event->pmu->stop(event, PERF_EF_UPDATE);
2397 * May race with the actual stop (through perf_pmu_output_stop()),
2398 * but it is only used for events with AUX ring buffer, and such
2399 * events will refuse to restart because of rb::aux_mmap_count==0,
2400 * see comments in perf_aux_output_begin().
2402 * Since this is happening on a event-local CPU, no trace is lost
2406 event->pmu->start(event, PERF_EF_START);
2411 static int perf_event_restart(struct perf_event *event)
2413 struct stop_event_data sd = {
2420 if (READ_ONCE(event->state) != PERF_EVENT_STATE_ACTIVE)
2423 /* matches smp_wmb() in event_sched_in() */
2427 * We only want to restart ACTIVE events, so if the event goes
2428 * inactive here (event->oncpu==-1), there's nothing more to do;
2429 * fall through with ret==-ENXIO.
2431 ret = cpu_function_call(READ_ONCE(event->oncpu),
2432 __perf_event_stop, &sd);
2433 } while (ret == -EAGAIN);
2439 * In order to contain the amount of racy and tricky in the address filter
2440 * configuration management, it is a two part process:
2442 * (p1) when userspace mappings change as a result of (1) or (2) or (3) below,
2443 * we update the addresses of corresponding vmas in
2444 * event::addr_filters_offs array and bump the event::addr_filters_gen;
2445 * (p2) when an event is scheduled in (pmu::add), it calls
2446 * perf_event_addr_filters_sync() which calls pmu::addr_filters_sync()
2447 * if the generation has changed since the previous call.
2449 * If (p1) happens while the event is active, we restart it to force (p2).
2451 * (1) perf_addr_filters_apply(): adjusting filters' offsets based on
2452 * pre-existing mappings, called once when new filters arrive via SET_FILTER
2454 * (2) perf_addr_filters_adjust(): adjusting filters' offsets based on newly
2455 * registered mapping, called for every new mmap(), with mm::mmap_sem down
2457 * (3) perf_event_addr_filters_exec(): clearing filters' offsets in the process
2460 void perf_event_addr_filters_sync(struct perf_event *event)
2462 struct perf_addr_filters_head *ifh = perf_event_addr_filters(event);
2464 if (!has_addr_filter(event))
2467 raw_spin_lock(&ifh->lock);
2468 if (event->addr_filters_gen != event->hw.addr_filters_gen) {
2469 event->pmu->addr_filters_sync(event);
2470 event->hw.addr_filters_gen = event->addr_filters_gen;
2472 raw_spin_unlock(&ifh->lock);
2474 EXPORT_SYMBOL_GPL(perf_event_addr_filters_sync);
2476 static int _perf_event_refresh(struct perf_event *event, int refresh)
2479 * not supported on inherited events
2481 if (event->attr.inherit || !is_sampling_event(event))
2484 atomic_add(refresh, &event->event_limit);
2485 _perf_event_enable(event);
2491 * See perf_event_disable()
2493 int perf_event_refresh(struct perf_event *event, int refresh)
2495 struct perf_event_context *ctx;
2498 ctx = perf_event_ctx_lock(event);
2499 ret = _perf_event_refresh(event, refresh);
2500 perf_event_ctx_unlock(event, ctx);
2504 EXPORT_SYMBOL_GPL(perf_event_refresh);
2506 static void ctx_sched_out(struct perf_event_context *ctx,
2507 struct perf_cpu_context *cpuctx,
2508 enum event_type_t event_type)
2510 int is_active = ctx->is_active;
2511 struct perf_event *event;
2513 lockdep_assert_held(&ctx->lock);
2515 if (likely(!ctx->nr_events)) {
2517 * See __perf_remove_from_context().
2519 WARN_ON_ONCE(ctx->is_active);
2521 WARN_ON_ONCE(cpuctx->task_ctx);
2525 ctx->is_active &= ~event_type;
2526 if (!(ctx->is_active & EVENT_ALL))
2530 WARN_ON_ONCE(cpuctx->task_ctx != ctx);
2531 if (!ctx->is_active)
2532 cpuctx->task_ctx = NULL;
2536 * Always update time if it was set; not only when it changes.
2537 * Otherwise we can 'forget' to update time for any but the last
2538 * context we sched out. For example:
2540 * ctx_sched_out(.event_type = EVENT_FLEXIBLE)
2541 * ctx_sched_out(.event_type = EVENT_PINNED)
2543 * would only update time for the pinned events.
2545 if (is_active & EVENT_TIME) {
2546 /* update (and stop) ctx time */
2547 update_context_time(ctx);
2548 update_cgrp_time_from_cpuctx(cpuctx);
2551 is_active ^= ctx->is_active; /* changed bits */
2553 if (!ctx->nr_active || !(is_active & EVENT_ALL))
2556 perf_pmu_disable(ctx->pmu);
2557 if (is_active & EVENT_PINNED) {
2558 list_for_each_entry(event, &ctx->pinned_groups, group_entry)
2559 group_sched_out(event, cpuctx, ctx);
2562 if (is_active & EVENT_FLEXIBLE) {
2563 list_for_each_entry(event, &ctx->flexible_groups, group_entry)
2564 group_sched_out(event, cpuctx, ctx);
2566 perf_pmu_enable(ctx->pmu);
2570 * Test whether two contexts are equivalent, i.e. whether they have both been
2571 * cloned from the same version of the same context.
2573 * Equivalence is measured using a generation number in the context that is
2574 * incremented on each modification to it; see unclone_ctx(), list_add_event()
2575 * and list_del_event().
2577 static int context_equiv(struct perf_event_context *ctx1,
2578 struct perf_event_context *ctx2)
2580 lockdep_assert_held(&ctx1->lock);
2581 lockdep_assert_held(&ctx2->lock);
2583 /* Pinning disables the swap optimization */
2584 if (ctx1->pin_count || ctx2->pin_count)
2587 /* If ctx1 is the parent of ctx2 */
2588 if (ctx1 == ctx2->parent_ctx && ctx1->generation == ctx2->parent_gen)
2591 /* If ctx2 is the parent of ctx1 */
2592 if (ctx1->parent_ctx == ctx2 && ctx1->parent_gen == ctx2->generation)
2596 * If ctx1 and ctx2 have the same parent; we flatten the parent
2597 * hierarchy, see perf_event_init_context().
2599 if (ctx1->parent_ctx && ctx1->parent_ctx == ctx2->parent_ctx &&
2600 ctx1->parent_gen == ctx2->parent_gen)
2607 static void __perf_event_sync_stat(struct perf_event *event,
2608 struct perf_event *next_event)
2612 if (!event->attr.inherit_stat)
2616 * Update the event value, we cannot use perf_event_read()
2617 * because we're in the middle of a context switch and have IRQs
2618 * disabled, which upsets smp_call_function_single(), however
2619 * we know the event must be on the current CPU, therefore we
2620 * don't need to use it.
2622 switch (event->state) {
2623 case PERF_EVENT_STATE_ACTIVE:
2624 event->pmu->read(event);
2627 case PERF_EVENT_STATE_INACTIVE:
2628 update_event_times(event);
2636 * In order to keep per-task stats reliable we need to flip the event
2637 * values when we flip the contexts.
2639 value = local64_read(&next_event->count);
2640 value = local64_xchg(&event->count, value);
2641 local64_set(&next_event->count, value);
2643 swap(event->total_time_enabled, next_event->total_time_enabled);
2644 swap(event->total_time_running, next_event->total_time_running);
2647 * Since we swizzled the values, update the user visible data too.
2649 perf_event_update_userpage(event);
2650 perf_event_update_userpage(next_event);
2653 static void perf_event_sync_stat(struct perf_event_context *ctx,
2654 struct perf_event_context *next_ctx)
2656 struct perf_event *event, *next_event;
2661 update_context_time(ctx);
2663 event = list_first_entry(&ctx->event_list,
2664 struct perf_event, event_entry);
2666 next_event = list_first_entry(&next_ctx->event_list,
2667 struct perf_event, event_entry);
2669 while (&event->event_entry != &ctx->event_list &&
2670 &next_event->event_entry != &next_ctx->event_list) {
2672 __perf_event_sync_stat(event, next_event);
2674 event = list_next_entry(event, event_entry);
2675 next_event = list_next_entry(next_event, event_entry);
2679 static void perf_event_context_sched_out(struct task_struct *task, int ctxn,
2680 struct task_struct *next)
2682 struct perf_event_context *ctx = task->perf_event_ctxp[ctxn];
2683 struct perf_event_context *next_ctx;
2684 struct perf_event_context *parent, *next_parent;
2685 struct perf_cpu_context *cpuctx;
2691 cpuctx = __get_cpu_context(ctx);
2692 if (!cpuctx->task_ctx)
2696 next_ctx = next->perf_event_ctxp[ctxn];
2700 parent = rcu_dereference(ctx->parent_ctx);
2701 next_parent = rcu_dereference(next_ctx->parent_ctx);
2703 /* If neither context have a parent context; they cannot be clones. */
2704 if (!parent && !next_parent)
2707 if (next_parent == ctx || next_ctx == parent || next_parent == parent) {
2709 * Looks like the two contexts are clones, so we might be
2710 * able to optimize the context switch. We lock both
2711 * contexts and check that they are clones under the
2712 * lock (including re-checking that neither has been
2713 * uncloned in the meantime). It doesn't matter which
2714 * order we take the locks because no other cpu could
2715 * be trying to lock both of these tasks.
2717 raw_spin_lock(&ctx->lock);
2718 raw_spin_lock_nested(&next_ctx->lock, SINGLE_DEPTH_NESTING);
2719 if (context_equiv(ctx, next_ctx)) {
2720 WRITE_ONCE(ctx->task, next);
2721 WRITE_ONCE(next_ctx->task, task);
2723 swap(ctx->task_ctx_data, next_ctx->task_ctx_data);
2726 * RCU_INIT_POINTER here is safe because we've not
2727 * modified the ctx and the above modification of
2728 * ctx->task and ctx->task_ctx_data are immaterial
2729 * since those values are always verified under
2730 * ctx->lock which we're now holding.
2732 RCU_INIT_POINTER(task->perf_event_ctxp[ctxn], next_ctx);
2733 RCU_INIT_POINTER(next->perf_event_ctxp[ctxn], ctx);
2737 perf_event_sync_stat(ctx, next_ctx);
2739 raw_spin_unlock(&next_ctx->lock);
2740 raw_spin_unlock(&ctx->lock);
2746 raw_spin_lock(&ctx->lock);
2747 task_ctx_sched_out(cpuctx, ctx);
2748 raw_spin_unlock(&ctx->lock);
2752 void perf_sched_cb_dec(struct pmu *pmu)
2754 this_cpu_dec(perf_sched_cb_usages);
2757 void perf_sched_cb_inc(struct pmu *pmu)
2759 this_cpu_inc(perf_sched_cb_usages);
2763 * This function provides the context switch callback to the lower code
2764 * layer. It is invoked ONLY when the context switch callback is enabled.
2766 static void perf_pmu_sched_task(struct task_struct *prev,
2767 struct task_struct *next,
2770 struct perf_cpu_context *cpuctx;
2772 unsigned long flags;
2777 local_irq_save(flags);
2781 list_for_each_entry_rcu(pmu, &pmus, entry) {
2782 if (pmu->sched_task) {
2783 cpuctx = this_cpu_ptr(pmu->pmu_cpu_context);
2785 perf_ctx_lock(cpuctx, cpuctx->task_ctx);
2787 perf_pmu_disable(pmu);
2789 pmu->sched_task(cpuctx->task_ctx, sched_in);
2791 perf_pmu_enable(pmu);
2793 perf_ctx_unlock(cpuctx, cpuctx->task_ctx);
2799 local_irq_restore(flags);
2802 static void perf_event_switch(struct task_struct *task,
2803 struct task_struct *next_prev, bool sched_in);
2805 #define for_each_task_context_nr(ctxn) \
2806 for ((ctxn) = 0; (ctxn) < perf_nr_task_contexts; (ctxn)++)
2809 * Called from scheduler to remove the events of the current task,
2810 * with interrupts disabled.
2812 * We stop each event and update the event value in event->count.
2814 * This does not protect us against NMI, but disable()
2815 * sets the disabled bit in the control field of event _before_
2816 * accessing the event control register. If a NMI hits, then it will
2817 * not restart the event.
2819 void __perf_event_task_sched_out(struct task_struct *task,
2820 struct task_struct *next)
2824 if (__this_cpu_read(perf_sched_cb_usages))
2825 perf_pmu_sched_task(task, next, false);
2827 if (atomic_read(&nr_switch_events))
2828 perf_event_switch(task, next, false);
2830 for_each_task_context_nr(ctxn)
2831 perf_event_context_sched_out(task, ctxn, next);
2834 * if cgroup events exist on this CPU, then we need
2835 * to check if we have to switch out PMU state.
2836 * cgroup event are system-wide mode only
2838 if (atomic_read(this_cpu_ptr(&perf_cgroup_events)))
2839 perf_cgroup_sched_out(task, next);
2843 * Called with IRQs disabled
2845 static void cpu_ctx_sched_out(struct perf_cpu_context *cpuctx,
2846 enum event_type_t event_type)
2848 ctx_sched_out(&cpuctx->ctx, cpuctx, event_type);
2852 ctx_pinned_sched_in(struct perf_event_context *ctx,
2853 struct perf_cpu_context *cpuctx)
2855 struct perf_event *event;
2857 list_for_each_entry(event, &ctx->pinned_groups, group_entry) {
2858 if (event->state <= PERF_EVENT_STATE_OFF)
2860 if (!event_filter_match(event))
2863 /* may need to reset tstamp_enabled */
2864 if (is_cgroup_event(event))
2865 perf_cgroup_mark_enabled(event, ctx);
2867 if (group_can_go_on(event, cpuctx, 1))
2868 group_sched_in(event, cpuctx, ctx);
2871 * If this pinned group hasn't been scheduled,
2872 * put it in error state.
2874 if (event->state == PERF_EVENT_STATE_INACTIVE) {
2875 update_group_times(event);
2876 event->state = PERF_EVENT_STATE_ERROR;
2882 ctx_flexible_sched_in(struct perf_event_context *ctx,
2883 struct perf_cpu_context *cpuctx)
2885 struct perf_event *event;
2888 list_for_each_entry(event, &ctx->flexible_groups, group_entry) {
2889 /* Ignore events in OFF or ERROR state */
2890 if (event->state <= PERF_EVENT_STATE_OFF)
2893 * Listen to the 'cpu' scheduling filter constraint
2896 if (!event_filter_match(event))
2899 /* may need to reset tstamp_enabled */
2900 if (is_cgroup_event(event))
2901 perf_cgroup_mark_enabled(event, ctx);
2903 if (group_can_go_on(event, cpuctx, can_add_hw)) {
2904 if (group_sched_in(event, cpuctx, ctx))
2911 ctx_sched_in(struct perf_event_context *ctx,
2912 struct perf_cpu_context *cpuctx,
2913 enum event_type_t event_type,
2914 struct task_struct *task)
2916 int is_active = ctx->is_active;
2919 lockdep_assert_held(&ctx->lock);
2921 if (likely(!ctx->nr_events))
2924 ctx->is_active |= (event_type | EVENT_TIME);
2927 cpuctx->task_ctx = ctx;
2929 WARN_ON_ONCE(cpuctx->task_ctx != ctx);
2932 is_active ^= ctx->is_active; /* changed bits */
2934 if (is_active & EVENT_TIME) {
2935 /* start ctx time */
2937 ctx->timestamp = now;
2938 perf_cgroup_set_timestamp(task, ctx);
2942 * First go through the list and put on any pinned groups
2943 * in order to give them the best chance of going on.
2945 if (is_active & EVENT_PINNED)
2946 ctx_pinned_sched_in(ctx, cpuctx);
2948 /* Then walk through the lower prio flexible groups */
2949 if (is_active & EVENT_FLEXIBLE)
2950 ctx_flexible_sched_in(ctx, cpuctx);
2953 static void cpu_ctx_sched_in(struct perf_cpu_context *cpuctx,
2954 enum event_type_t event_type,
2955 struct task_struct *task)
2957 struct perf_event_context *ctx = &cpuctx->ctx;
2959 ctx_sched_in(ctx, cpuctx, event_type, task);
2962 static void perf_event_context_sched_in(struct perf_event_context *ctx,
2963 struct task_struct *task)
2965 struct perf_cpu_context *cpuctx;
2967 cpuctx = __get_cpu_context(ctx);
2968 if (cpuctx->task_ctx == ctx)
2971 perf_ctx_lock(cpuctx, ctx);
2972 perf_pmu_disable(ctx->pmu);
2974 * We want to keep the following priority order:
2975 * cpu pinned (that don't need to move), task pinned,
2976 * cpu flexible, task flexible.
2978 cpu_ctx_sched_out(cpuctx, EVENT_FLEXIBLE);
2979 perf_event_sched_in(cpuctx, ctx, task);
2980 perf_pmu_enable(ctx->pmu);
2981 perf_ctx_unlock(cpuctx, ctx);
2985 * Called from scheduler to add the events of the current task
2986 * with interrupts disabled.
2988 * We restore the event value and then enable it.
2990 * This does not protect us against NMI, but enable()
2991 * sets the enabled bit in the control field of event _before_
2992 * accessing the event control register. If a NMI hits, then it will
2993 * keep the event running.
2995 void __perf_event_task_sched_in(struct task_struct *prev,
2996 struct task_struct *task)
2998 struct perf_event_context *ctx;
3002 * If cgroup events exist on this CPU, then we need to check if we have
3003 * to switch in PMU state; cgroup event are system-wide mode only.
3005 * Since cgroup events are CPU events, we must schedule these in before
3006 * we schedule in the task events.
3008 if (atomic_read(this_cpu_ptr(&perf_cgroup_events)))
3009 perf_cgroup_sched_in(prev, task);
3011 for_each_task_context_nr(ctxn) {
3012 ctx = task->perf_event_ctxp[ctxn];
3016 perf_event_context_sched_in(ctx, task);
3019 if (atomic_read(&nr_switch_events))
3020 perf_event_switch(task, prev, true);
3022 if (__this_cpu_read(perf_sched_cb_usages))
3023 perf_pmu_sched_task(prev, task, true);
3026 static u64 perf_calculate_period(struct perf_event *event, u64 nsec, u64 count)
3028 u64 frequency = event->attr.sample_freq;
3029 u64 sec = NSEC_PER_SEC;
3030 u64 divisor, dividend;
3032 int count_fls, nsec_fls, frequency_fls, sec_fls;
3034 count_fls = fls64(count);
3035 nsec_fls = fls64(nsec);
3036 frequency_fls = fls64(frequency);
3040 * We got @count in @nsec, with a target of sample_freq HZ
3041 * the target period becomes:
3044 * period = -------------------
3045 * @nsec * sample_freq
3050 * Reduce accuracy by one bit such that @a and @b converge
3051 * to a similar magnitude.
3053 #define REDUCE_FLS(a, b) \
3055 if (a##_fls > b##_fls) { \
3065 * Reduce accuracy until either term fits in a u64, then proceed with
3066 * the other, so that finally we can do a u64/u64 division.
3068 while (count_fls + sec_fls > 64 && nsec_fls + frequency_fls > 64) {
3069 REDUCE_FLS(nsec, frequency);
3070 REDUCE_FLS(sec, count);
3073 if (count_fls + sec_fls > 64) {
3074 divisor = nsec * frequency;
3076 while (count_fls + sec_fls > 64) {
3077 REDUCE_FLS(count, sec);
3081 dividend = count * sec;
3083 dividend = count * sec;
3085 while (nsec_fls + frequency_fls > 64) {
3086 REDUCE_FLS(nsec, frequency);
3090 divisor = nsec * frequency;
3096 return div64_u64(dividend, divisor);
3099 static DEFINE_PER_CPU(int, perf_throttled_count);
3100 static DEFINE_PER_CPU(u64, perf_throttled_seq);
3102 static void perf_adjust_period(struct perf_event *event, u64 nsec, u64 count, bool disable)
3104 struct hw_perf_event *hwc = &event->hw;
3105 s64 period, sample_period;
3108 period = perf_calculate_period(event, nsec, count);
3110 delta = (s64)(period - hwc->sample_period);
3111 delta = (delta + 7) / 8; /* low pass filter */
3113 sample_period = hwc->sample_period + delta;
3118 hwc->sample_period = sample_period;
3120 if (local64_read(&hwc->period_left) > 8*sample_period) {
3122 event->pmu->stop(event, PERF_EF_UPDATE);
3124 local64_set(&hwc->period_left, 0);
3127 event->pmu->start(event, PERF_EF_RELOAD);
3132 * combine freq adjustment with unthrottling to avoid two passes over the
3133 * events. At the same time, make sure, having freq events does not change
3134 * the rate of unthrottling as that would introduce bias.
3136 static void perf_adjust_freq_unthr_context(struct perf_event_context *ctx,
3139 struct perf_event *event;
3140 struct hw_perf_event *hwc;
3141 u64 now, period = TICK_NSEC;
3145 * only need to iterate over all events iff:
3146 * - context have events in frequency mode (needs freq adjust)
3147 * - there are events to unthrottle on this cpu
3149 if (!(ctx->nr_freq || needs_unthr))
3152 raw_spin_lock(&ctx->lock);
3153 perf_pmu_disable(ctx->pmu);
3155 list_for_each_entry_rcu(event, &ctx->event_list, event_entry) {
3156 if (event->state != PERF_EVENT_STATE_ACTIVE)
3159 if (!event_filter_match(event))
3162 perf_pmu_disable(event->pmu);
3166 if (hwc->interrupts == MAX_INTERRUPTS) {
3167 hwc->interrupts = 0;
3168 perf_log_throttle(event, 1);
3169 event->pmu->start(event, 0);
3172 if (!event->attr.freq || !event->attr.sample_freq)
3176 * stop the event and update event->count
3178 event->pmu->stop(event, PERF_EF_UPDATE);
3180 now = local64_read(&event->count);
3181 delta = now - hwc->freq_count_stamp;
3182 hwc->freq_count_stamp = now;
3186 * reload only if value has changed
3187 * we have stopped the event so tell that
3188 * to perf_adjust_period() to avoid stopping it
3192 perf_adjust_period(event, period, delta, false);
3194 event->pmu->start(event, delta > 0 ? PERF_EF_RELOAD : 0);
3196 perf_pmu_enable(event->pmu);
3199 perf_pmu_enable(ctx->pmu);
3200 raw_spin_unlock(&ctx->lock);
3204 * Round-robin a context's events:
3206 static void rotate_ctx(struct perf_event_context *ctx)
3209 * Rotate the first entry last of non-pinned groups. Rotation might be
3210 * disabled by the inheritance code.
3212 if (!ctx->rotate_disable)
3213 list_rotate_left(&ctx->flexible_groups);
3216 static int perf_rotate_context(struct perf_cpu_context *cpuctx)
3218 struct perf_event_context *ctx = NULL;
3221 if (cpuctx->ctx.nr_events) {
3222 if (cpuctx->ctx.nr_events != cpuctx->ctx.nr_active)
3226 ctx = cpuctx->task_ctx;
3227 if (ctx && ctx->nr_events) {
3228 if (ctx->nr_events != ctx->nr_active)
3235 perf_ctx_lock(cpuctx, cpuctx->task_ctx);
3236 perf_pmu_disable(cpuctx->ctx.pmu);
3238 cpu_ctx_sched_out(cpuctx, EVENT_FLEXIBLE);
3240 ctx_sched_out(ctx, cpuctx, EVENT_FLEXIBLE);
3242 rotate_ctx(&cpuctx->ctx);
3246 perf_event_sched_in(cpuctx, ctx, current);
3248 perf_pmu_enable(cpuctx->ctx.pmu);
3249 perf_ctx_unlock(cpuctx, cpuctx->task_ctx);
3255 void perf_event_task_tick(void)
3257 struct list_head *head = this_cpu_ptr(&active_ctx_list);
3258 struct perf_event_context *ctx, *tmp;
3261 WARN_ON(!irqs_disabled());
3263 __this_cpu_inc(perf_throttled_seq);
3264 throttled = __this_cpu_xchg(perf_throttled_count, 0);
3265 tick_dep_clear_cpu(smp_processor_id(), TICK_DEP_BIT_PERF_EVENTS);
3267 list_for_each_entry_safe(ctx, tmp, head, active_ctx_list)
3268 perf_adjust_freq_unthr_context(ctx, throttled);
3271 static int event_enable_on_exec(struct perf_event *event,
3272 struct perf_event_context *ctx)
3274 if (!event->attr.enable_on_exec)
3277 event->attr.enable_on_exec = 0;
3278 if (event->state >= PERF_EVENT_STATE_INACTIVE)
3281 __perf_event_mark_enabled(event);
3287 * Enable all of a task's events that have been marked enable-on-exec.
3288 * This expects task == current.
3290 static void perf_event_enable_on_exec(int ctxn)
3292 struct perf_event_context *ctx, *clone_ctx = NULL;
3293 struct perf_cpu_context *cpuctx;
3294 struct perf_event *event;
3295 unsigned long flags;
3298 local_irq_save(flags);
3299 ctx = current->perf_event_ctxp[ctxn];
3300 if (!ctx || !ctx->nr_events)
3303 cpuctx = __get_cpu_context(ctx);
3304 perf_ctx_lock(cpuctx, ctx);
3305 ctx_sched_out(ctx, cpuctx, EVENT_TIME);
3306 list_for_each_entry(event, &ctx->event_list, event_entry)
3307 enabled |= event_enable_on_exec(event, ctx);
3310 * Unclone and reschedule this context if we enabled any event.
3313 clone_ctx = unclone_ctx(ctx);
3314 ctx_resched(cpuctx, ctx);
3316 perf_ctx_unlock(cpuctx, ctx);
3319 local_irq_restore(flags);
3325 struct perf_read_data {
3326 struct perf_event *event;
3332 * Cross CPU call to read the hardware event
3334 static void __perf_event_read(void *info)
3336 struct perf_read_data *data = info;
3337 struct perf_event *sub, *event = data->event;
3338 struct perf_event_context *ctx = event->ctx;
3339 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
3340 struct pmu *pmu = event->pmu;
3343 * If this is a task context, we need to check whether it is
3344 * the current task context of this cpu. If not it has been
3345 * scheduled out before the smp call arrived. In that case
3346 * event->count would have been updated to a recent sample
3347 * when the event was scheduled out.
3349 if (ctx->task && cpuctx->task_ctx != ctx)
3352 raw_spin_lock(&ctx->lock);
3353 if (ctx->is_active) {
3354 update_context_time(ctx);
3355 update_cgrp_time_from_event(event);
3358 update_event_times(event);
3359 if (event->state != PERF_EVENT_STATE_ACTIVE)
3368 pmu->start_txn(pmu, PERF_PMU_TXN_READ);
3372 list_for_each_entry(sub, &event->sibling_list, group_entry) {
3373 update_event_times(sub);
3374 if (sub->state == PERF_EVENT_STATE_ACTIVE) {
3376 * Use sibling's PMU rather than @event's since
3377 * sibling could be on different (eg: software) PMU.
3379 sub->pmu->read(sub);
3383 data->ret = pmu->commit_txn(pmu);
3386 raw_spin_unlock(&ctx->lock);
3389 static inline u64 perf_event_count(struct perf_event *event)
3391 if (event->pmu->count)
3392 return event->pmu->count(event);
3394 return __perf_event_count(event);
3398 * NMI-safe method to read a local event, that is an event that
3400 * - either for the current task, or for this CPU
3401 * - does not have inherit set, for inherited task events
3402 * will not be local and we cannot read them atomically
3403 * - must not have a pmu::count method
3405 u64 perf_event_read_local(struct perf_event *event)
3407 unsigned long flags;
3411 * Disabling interrupts avoids all counter scheduling (context
3412 * switches, timer based rotation and IPIs).
3414 local_irq_save(flags);
3416 /* If this is a per-task event, it must be for current */
3417 WARN_ON_ONCE((event->attach_state & PERF_ATTACH_TASK) &&
3418 event->hw.target != current);
3420 /* If this is a per-CPU event, it must be for this CPU */
3421 WARN_ON_ONCE(!(event->attach_state & PERF_ATTACH_TASK) &&
3422 event->cpu != smp_processor_id());
3425 * It must not be an event with inherit set, we cannot read
3426 * all child counters from atomic context.
3428 WARN_ON_ONCE(event->attr.inherit);
3431 * It must not have a pmu::count method, those are not
3434 WARN_ON_ONCE(event->pmu->count);
3437 * If the event is currently on this CPU, its either a per-task event,
3438 * or local to this CPU. Furthermore it means its ACTIVE (otherwise
3441 if (event->oncpu == smp_processor_id())
3442 event->pmu->read(event);
3444 val = local64_read(&event->count);
3445 local_irq_restore(flags);
3450 static int perf_event_read(struct perf_event *event, bool group)
3455 * If event is enabled and currently active on a CPU, update the
3456 * value in the event structure:
3458 if (event->state == PERF_EVENT_STATE_ACTIVE) {
3459 struct perf_read_data data = {
3464 smp_call_function_single(event->oncpu,
3465 __perf_event_read, &data, 1);
3467 } else if (event->state == PERF_EVENT_STATE_INACTIVE) {
3468 struct perf_event_context *ctx = event->ctx;
3469 unsigned long flags;
3471 raw_spin_lock_irqsave(&ctx->lock, flags);
3473 * may read while context is not active
3474 * (e.g., thread is blocked), in that case
3475 * we cannot update context time
3477 if (ctx->is_active) {
3478 update_context_time(ctx);
3479 update_cgrp_time_from_event(event);
3482 update_group_times(event);
3484 update_event_times(event);
3485 raw_spin_unlock_irqrestore(&ctx->lock, flags);
3492 * Initialize the perf_event context in a task_struct:
3494 static void __perf_event_init_context(struct perf_event_context *ctx)
3496 raw_spin_lock_init(&ctx->lock);
3497 mutex_init(&ctx->mutex);
3498 INIT_LIST_HEAD(&ctx->active_ctx_list);
3499 INIT_LIST_HEAD(&ctx->pinned_groups);
3500 INIT_LIST_HEAD(&ctx->flexible_groups);
3501 INIT_LIST_HEAD(&ctx->event_list);
3502 atomic_set(&ctx->refcount, 1);
3505 static struct perf_event_context *
3506 alloc_perf_context(struct pmu *pmu, struct task_struct *task)
3508 struct perf_event_context *ctx;
3510 ctx = kzalloc(sizeof(struct perf_event_context), GFP_KERNEL);
3514 __perf_event_init_context(ctx);
3517 get_task_struct(task);
3524 static struct task_struct *
3525 find_lively_task_by_vpid(pid_t vpid)
3527 struct task_struct *task;
3533 task = find_task_by_vpid(vpid);
3535 get_task_struct(task);
3539 return ERR_PTR(-ESRCH);
3545 * Returns a matching context with refcount and pincount.
3547 static struct perf_event_context *
3548 find_get_context(struct pmu *pmu, struct task_struct *task,
3549 struct perf_event *event)
3551 struct perf_event_context *ctx, *clone_ctx = NULL;
3552 struct perf_cpu_context *cpuctx;
3553 void *task_ctx_data = NULL;
3554 unsigned long flags;
3556 int cpu = event->cpu;
3559 /* Must be root to operate on a CPU event: */
3560 if (perf_paranoid_cpu() && !capable(CAP_SYS_ADMIN))
3561 return ERR_PTR(-EACCES);
3564 * We could be clever and allow to attach a event to an
3565 * offline CPU and activate it when the CPU comes up, but
3568 if (!cpu_online(cpu))
3569 return ERR_PTR(-ENODEV);
3571 cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
3580 ctxn = pmu->task_ctx_nr;
3584 if (event->attach_state & PERF_ATTACH_TASK_DATA) {
3585 task_ctx_data = kzalloc(pmu->task_ctx_size, GFP_KERNEL);
3586 if (!task_ctx_data) {
3593 ctx = perf_lock_task_context(task, ctxn, &flags);
3595 clone_ctx = unclone_ctx(ctx);
3598 if (task_ctx_data && !ctx->task_ctx_data) {
3599 ctx->task_ctx_data = task_ctx_data;
3600 task_ctx_data = NULL;
3602 raw_spin_unlock_irqrestore(&ctx->lock, flags);
3607 ctx = alloc_perf_context(pmu, task);
3612 if (task_ctx_data) {
3613 ctx->task_ctx_data = task_ctx_data;
3614 task_ctx_data = NULL;
3618 mutex_lock(&task->perf_event_mutex);
3620 * If it has already passed perf_event_exit_task().
3621 * we must see PF_EXITING, it takes this mutex too.
3623 if (task->flags & PF_EXITING)
3625 else if (task->perf_event_ctxp[ctxn])
3630 rcu_assign_pointer(task->perf_event_ctxp[ctxn], ctx);
3632 mutex_unlock(&task->perf_event_mutex);
3634 if (unlikely(err)) {
3643 kfree(task_ctx_data);
3647 kfree(task_ctx_data);
3648 return ERR_PTR(err);
3651 static void perf_event_free_filter(struct perf_event *event);
3652 static void perf_event_free_bpf_prog(struct perf_event *event);
3654 static void free_event_rcu(struct rcu_head *head)
3656 struct perf_event *event;
3658 event = container_of(head, struct perf_event, rcu_head);
3660 put_pid_ns(event->ns);
3661 perf_event_free_filter(event);
3665 static void ring_buffer_attach(struct perf_event *event,
3666 struct ring_buffer *rb);
3668 static void unaccount_event_cpu(struct perf_event *event, int cpu)
3673 if (is_cgroup_event(event))
3674 atomic_dec(&per_cpu(perf_cgroup_events, cpu));
3677 #ifdef CONFIG_NO_HZ_FULL
3678 static DEFINE_SPINLOCK(nr_freq_lock);
3681 static void unaccount_freq_event_nohz(void)
3683 #ifdef CONFIG_NO_HZ_FULL
3684 spin_lock(&nr_freq_lock);
3685 if (atomic_dec_and_test(&nr_freq_events))
3686 tick_nohz_dep_clear(TICK_DEP_BIT_PERF_EVENTS);
3687 spin_unlock(&nr_freq_lock);
3691 static void unaccount_freq_event(void)
3693 if (tick_nohz_full_enabled())
3694 unaccount_freq_event_nohz();
3696 atomic_dec(&nr_freq_events);
3699 static void unaccount_event(struct perf_event *event)
3706 if (event->attach_state & PERF_ATTACH_TASK)
3708 if (event->attr.mmap || event->attr.mmap_data)
3709 atomic_dec(&nr_mmap_events);
3710 if (event->attr.comm)
3711 atomic_dec(&nr_comm_events);
3712 if (event->attr.task)
3713 atomic_dec(&nr_task_events);
3714 if (event->attr.freq)
3715 unaccount_freq_event();
3716 if (event->attr.context_switch) {
3718 atomic_dec(&nr_switch_events);
3720 if (is_cgroup_event(event))
3722 if (has_branch_stack(event))
3726 if (!atomic_add_unless(&perf_sched_count, -1, 1))
3727 schedule_delayed_work(&perf_sched_work, HZ);
3730 unaccount_event_cpu(event, event->cpu);
3733 static void perf_sched_delayed(struct work_struct *work)
3735 mutex_lock(&perf_sched_mutex);
3736 if (atomic_dec_and_test(&perf_sched_count))
3737 static_branch_disable(&perf_sched_events);
3738 mutex_unlock(&perf_sched_mutex);
3742 * The following implement mutual exclusion of events on "exclusive" pmus
3743 * (PERF_PMU_CAP_EXCLUSIVE). Such pmus can only have one event scheduled
3744 * at a time, so we disallow creating events that might conflict, namely:
3746 * 1) cpu-wide events in the presence of per-task events,
3747 * 2) per-task events in the presence of cpu-wide events,
3748 * 3) two matching events on the same context.
3750 * The former two cases are handled in the allocation path (perf_event_alloc(),
3751 * _free_event()), the latter -- before the first perf_install_in_context().
3753 static int exclusive_event_init(struct perf_event *event)
3755 struct pmu *pmu = event->pmu;
3757 if (!(pmu->capabilities & PERF_PMU_CAP_EXCLUSIVE))
3761 * Prevent co-existence of per-task and cpu-wide events on the
3762 * same exclusive pmu.
3764 * Negative pmu::exclusive_cnt means there are cpu-wide
3765 * events on this "exclusive" pmu, positive means there are
3768 * Since this is called in perf_event_alloc() path, event::ctx
3769 * doesn't exist yet; it is, however, safe to use PERF_ATTACH_TASK
3770 * to mean "per-task event", because unlike other attach states it
3771 * never gets cleared.
3773 if (event->attach_state & PERF_ATTACH_TASK) {
3774 if (!atomic_inc_unless_negative(&pmu->exclusive_cnt))
3777 if (!atomic_dec_unless_positive(&pmu->exclusive_cnt))
3784 static void exclusive_event_destroy(struct perf_event *event)
3786 struct pmu *pmu = event->pmu;
3788 if (!(pmu->capabilities & PERF_PMU_CAP_EXCLUSIVE))
3791 /* see comment in exclusive_event_init() */
3792 if (event->attach_state & PERF_ATTACH_TASK)
3793 atomic_dec(&pmu->exclusive_cnt);
3795 atomic_inc(&pmu->exclusive_cnt);
3798 static bool exclusive_event_match(struct perf_event *e1, struct perf_event *e2)
3800 if ((e1->pmu->capabilities & PERF_PMU_CAP_EXCLUSIVE) &&
3801 (e1->cpu == e2->cpu ||
3808 /* Called under the same ctx::mutex as perf_install_in_context() */
3809 static bool exclusive_event_installable(struct perf_event *event,
3810 struct perf_event_context *ctx)
3812 struct perf_event *iter_event;
3813 struct pmu *pmu = event->pmu;
3815 if (!(pmu->capabilities & PERF_PMU_CAP_EXCLUSIVE))
3818 list_for_each_entry(iter_event, &ctx->event_list, event_entry) {
3819 if (exclusive_event_match(iter_event, event))
3826 static void perf_addr_filters_splice(struct perf_event *event,
3827 struct list_head *head);
3829 static void _free_event(struct perf_event *event)
3831 irq_work_sync(&event->pending);
3833 unaccount_event(event);
3837 * Can happen when we close an event with re-directed output.
3839 * Since we have a 0 refcount, perf_mmap_close() will skip
3840 * over us; possibly making our ring_buffer_put() the last.
3842 mutex_lock(&event->mmap_mutex);
3843 ring_buffer_attach(event, NULL);
3844 mutex_unlock(&event->mmap_mutex);
3847 if (is_cgroup_event(event))
3848 perf_detach_cgroup(event);
3850 if (!event->parent) {
3851 if (event->attr.sample_type & PERF_SAMPLE_CALLCHAIN)
3852 put_callchain_buffers();
3855 perf_event_free_bpf_prog(event);
3856 perf_addr_filters_splice(event, NULL);
3857 kfree(event->addr_filters_offs);
3860 event->destroy(event);
3863 put_ctx(event->ctx);
3865 exclusive_event_destroy(event);
3866 module_put(event->pmu->module);
3868 call_rcu(&event->rcu_head, free_event_rcu);
3872 * Used to free events which have a known refcount of 1, such as in error paths
3873 * where the event isn't exposed yet and inherited events.
3875 static void free_event(struct perf_event *event)
3877 if (WARN(atomic_long_cmpxchg(&event->refcount, 1, 0) != 1,
3878 "unexpected event refcount: %ld; ptr=%p\n",
3879 atomic_long_read(&event->refcount), event)) {
3880 /* leak to avoid use-after-free */
3888 * Remove user event from the owner task.
3890 static void perf_remove_from_owner(struct perf_event *event)
3892 struct task_struct *owner;
3896 * Matches the smp_store_release() in perf_event_exit_task(). If we
3897 * observe !owner it means the list deletion is complete and we can
3898 * indeed free this event, otherwise we need to serialize on
3899 * owner->perf_event_mutex.
3901 owner = lockless_dereference(event->owner);
3904 * Since delayed_put_task_struct() also drops the last
3905 * task reference we can safely take a new reference
3906 * while holding the rcu_read_lock().
3908 get_task_struct(owner);
3914 * If we're here through perf_event_exit_task() we're already
3915 * holding ctx->mutex which would be an inversion wrt. the
3916 * normal lock order.
3918 * However we can safely take this lock because its the child
3921 mutex_lock_nested(&owner->perf_event_mutex, SINGLE_DEPTH_NESTING);
3924 * We have to re-check the event->owner field, if it is cleared
3925 * we raced with perf_event_exit_task(), acquiring the mutex
3926 * ensured they're done, and we can proceed with freeing the
3930 list_del_init(&event->owner_entry);
3931 smp_store_release(&event->owner, NULL);
3933 mutex_unlock(&owner->perf_event_mutex);
3934 put_task_struct(owner);
3938 static void put_event(struct perf_event *event)
3940 if (!atomic_long_dec_and_test(&event->refcount))
3947 * Kill an event dead; while event:refcount will preserve the event
3948 * object, it will not preserve its functionality. Once the last 'user'
3949 * gives up the object, we'll destroy the thing.
3951 int perf_event_release_kernel(struct perf_event *event)
3953 struct perf_event_context *ctx = event->ctx;
3954 struct perf_event *child, *tmp;
3957 * If we got here through err_file: fput(event_file); we will not have
3958 * attached to a context yet.
3961 WARN_ON_ONCE(event->attach_state &
3962 (PERF_ATTACH_CONTEXT|PERF_ATTACH_GROUP));
3966 if (!is_kernel_event(event))
3967 perf_remove_from_owner(event);
3969 ctx = perf_event_ctx_lock(event);
3970 WARN_ON_ONCE(ctx->parent_ctx);
3971 perf_remove_from_context(event, DETACH_GROUP);
3973 raw_spin_lock_irq(&ctx->lock);
3975 * Mark this even as STATE_DEAD, there is no external reference to it
3978 * Anybody acquiring event->child_mutex after the below loop _must_
3979 * also see this, most importantly inherit_event() which will avoid
3980 * placing more children on the list.
3982 * Thus this guarantees that we will in fact observe and kill _ALL_
3985 event->state = PERF_EVENT_STATE_DEAD;
3986 raw_spin_unlock_irq(&ctx->lock);
3988 perf_event_ctx_unlock(event, ctx);
3991 mutex_lock(&event->child_mutex);
3992 list_for_each_entry(child, &event->child_list, child_list) {
3995 * Cannot change, child events are not migrated, see the
3996 * comment with perf_event_ctx_lock_nested().
3998 ctx = lockless_dereference(child->ctx);
4000 * Since child_mutex nests inside ctx::mutex, we must jump
4001 * through hoops. We start by grabbing a reference on the ctx.
4003 * Since the event cannot get freed while we hold the
4004 * child_mutex, the context must also exist and have a !0
4010 * Now that we have a ctx ref, we can drop child_mutex, and
4011 * acquire ctx::mutex without fear of it going away. Then we
4012 * can re-acquire child_mutex.
4014 mutex_unlock(&event->child_mutex);
4015 mutex_lock(&ctx->mutex);
4016 mutex_lock(&event->child_mutex);
4019 * Now that we hold ctx::mutex and child_mutex, revalidate our
4020 * state, if child is still the first entry, it didn't get freed
4021 * and we can continue doing so.
4023 tmp = list_first_entry_or_null(&event->child_list,
4024 struct perf_event, child_list);
4026 perf_remove_from_context(child, DETACH_GROUP);
4027 list_del(&child->child_list);
4030 * This matches the refcount bump in inherit_event();
4031 * this can't be the last reference.
4036 mutex_unlock(&event->child_mutex);
4037 mutex_unlock(&ctx->mutex);
4041 mutex_unlock(&event->child_mutex);
4044 put_event(event); /* Must be the 'last' reference */
4047 EXPORT_SYMBOL_GPL(perf_event_release_kernel);
4050 * Called when the last reference to the file is gone.
4052 static int perf_release(struct inode *inode, struct file *file)
4054 perf_event_release_kernel(file->private_data);
4058 u64 perf_event_read_value(struct perf_event *event, u64 *enabled, u64 *running)
4060 struct perf_event *child;
4066 mutex_lock(&event->child_mutex);
4068 (void)perf_event_read(event, false);
4069 total += perf_event_count(event);
4071 *enabled += event->total_time_enabled +
4072 atomic64_read(&event->child_total_time_enabled);
4073 *running += event->total_time_running +
4074 atomic64_read(&event->child_total_time_running);
4076 list_for_each_entry(child, &event->child_list, child_list) {
4077 (void)perf_event_read(child, false);
4078 total += perf_event_count(child);
4079 *enabled += child->total_time_enabled;
4080 *running += child->total_time_running;
4082 mutex_unlock(&event->child_mutex);
4086 EXPORT_SYMBOL_GPL(perf_event_read_value);
4088 static int __perf_read_group_add(struct perf_event *leader,
4089 u64 read_format, u64 *values)
4091 struct perf_event *sub;
4092 int n = 1; /* skip @nr */
4095 ret = perf_event_read(leader, true);
4100 * Since we co-schedule groups, {enabled,running} times of siblings
4101 * will be identical to those of the leader, so we only publish one
4104 if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED) {
4105 values[n++] += leader->total_time_enabled +
4106 atomic64_read(&leader->child_total_time_enabled);
4109 if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING) {
4110 values[n++] += leader->total_time_running +
4111 atomic64_read(&leader->child_total_time_running);
4115 * Write {count,id} tuples for every sibling.
4117 values[n++] += perf_event_count(leader);
4118 if (read_format & PERF_FORMAT_ID)
4119 values[n++] = primary_event_id(leader);
4121 list_for_each_entry(sub, &leader->sibling_list, group_entry) {
4122 values[n++] += perf_event_count(sub);
4123 if (read_format & PERF_FORMAT_ID)
4124 values[n++] = primary_event_id(sub);
4130 static int perf_read_group(struct perf_event *event,
4131 u64 read_format, char __user *buf)
4133 struct perf_event *leader = event->group_leader, *child;
4134 struct perf_event_context *ctx = leader->ctx;
4138 lockdep_assert_held(&ctx->mutex);
4140 values = kzalloc(event->read_size, GFP_KERNEL);
4144 values[0] = 1 + leader->nr_siblings;
4147 * By locking the child_mutex of the leader we effectively
4148 * lock the child list of all siblings.. XXX explain how.
4150 mutex_lock(&leader->child_mutex);
4152 ret = __perf_read_group_add(leader, read_format, values);
4156 list_for_each_entry(child, &leader->child_list, child_list) {
4157 ret = __perf_read_group_add(child, read_format, values);
4162 mutex_unlock(&leader->child_mutex);
4164 ret = event->read_size;
4165 if (copy_to_user(buf, values, event->read_size))
4170 mutex_unlock(&leader->child_mutex);
4176 static int perf_read_one(struct perf_event *event,
4177 u64 read_format, char __user *buf)
4179 u64 enabled, running;
4183 values[n++] = perf_event_read_value(event, &enabled, &running);
4184 if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED)
4185 values[n++] = enabled;
4186 if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING)
4187 values[n++] = running;
4188 if (read_format & PERF_FORMAT_ID)
4189 values[n++] = primary_event_id(event);
4191 if (copy_to_user(buf, values, n * sizeof(u64)))
4194 return n * sizeof(u64);
4197 static bool is_event_hup(struct perf_event *event)
4201 if (event->state > PERF_EVENT_STATE_EXIT)
4204 mutex_lock(&event->child_mutex);
4205 no_children = list_empty(&event->child_list);
4206 mutex_unlock(&event->child_mutex);
4211 * Read the performance event - simple non blocking version for now
4214 __perf_read(struct perf_event *event, char __user *buf, size_t count)
4216 u64 read_format = event->attr.read_format;
4220 * Return end-of-file for a read on a event that is in
4221 * error state (i.e. because it was pinned but it couldn't be
4222 * scheduled on to the CPU at some point).
4224 if (event->state == PERF_EVENT_STATE_ERROR)
4227 if (count < event->read_size)
4230 WARN_ON_ONCE(event->ctx->parent_ctx);
4231 if (read_format & PERF_FORMAT_GROUP)
4232 ret = perf_read_group(event, read_format, buf);
4234 ret = perf_read_one(event, read_format, buf);
4240 perf_read(struct file *file, char __user *buf, size_t count, loff_t *ppos)
4242 struct perf_event *event = file->private_data;
4243 struct perf_event_context *ctx;
4246 ctx = perf_event_ctx_lock(event);
4247 ret = __perf_read(event, buf, count);
4248 perf_event_ctx_unlock(event, ctx);
4253 static unsigned int perf_poll(struct file *file, poll_table *wait)
4255 struct perf_event *event = file->private_data;
4256 struct ring_buffer *rb;
4257 unsigned int events = POLLHUP;
4259 poll_wait(file, &event->waitq, wait);
4261 if (is_event_hup(event))
4265 * Pin the event->rb by taking event->mmap_mutex; otherwise
4266 * perf_event_set_output() can swizzle our rb and make us miss wakeups.
4268 mutex_lock(&event->mmap_mutex);
4271 events = atomic_xchg(&rb->poll, 0);
4272 mutex_unlock(&event->mmap_mutex);
4276 static void _perf_event_reset(struct perf_event *event)
4278 (void)perf_event_read(event, false);
4279 local64_set(&event->count, 0);
4280 perf_event_update_userpage(event);
4284 * Holding the top-level event's child_mutex means that any
4285 * descendant process that has inherited this event will block
4286 * in perf_event_exit_event() if it goes to exit, thus satisfying the
4287 * task existence requirements of perf_event_enable/disable.
4289 static void perf_event_for_each_child(struct perf_event *event,
4290 void (*func)(struct perf_event *))
4292 struct perf_event *child;
4294 WARN_ON_ONCE(event->ctx->parent_ctx);
4296 mutex_lock(&event->child_mutex);
4298 list_for_each_entry(child, &event->child_list, child_list)
4300 mutex_unlock(&event->child_mutex);
4303 static void perf_event_for_each(struct perf_event *event,
4304 void (*func)(struct perf_event *))
4306 struct perf_event_context *ctx = event->ctx;
4307 struct perf_event *sibling;
4309 lockdep_assert_held(&ctx->mutex);
4311 event = event->group_leader;
4313 perf_event_for_each_child(event, func);
4314 list_for_each_entry(sibling, &event->sibling_list, group_entry)
4315 perf_event_for_each_child(sibling, func);
4318 static void __perf_event_period(struct perf_event *event,
4319 struct perf_cpu_context *cpuctx,
4320 struct perf_event_context *ctx,
4323 u64 value = *((u64 *)info);
4326 if (event->attr.freq) {
4327 event->attr.sample_freq = value;
4329 event->attr.sample_period = value;
4330 event->hw.sample_period = value;
4333 active = (event->state == PERF_EVENT_STATE_ACTIVE);
4335 perf_pmu_disable(ctx->pmu);
4337 * We could be throttled; unthrottle now to avoid the tick
4338 * trying to unthrottle while we already re-started the event.
4340 if (event->hw.interrupts == MAX_INTERRUPTS) {
4341 event->hw.interrupts = 0;
4342 perf_log_throttle(event, 1);
4344 event->pmu->stop(event, PERF_EF_UPDATE);
4347 local64_set(&event->hw.period_left, 0);
4350 event->pmu->start(event, PERF_EF_RELOAD);
4351 perf_pmu_enable(ctx->pmu);
4355 static int perf_event_period(struct perf_event *event, u64 __user *arg)
4359 if (!is_sampling_event(event))
4362 if (copy_from_user(&value, arg, sizeof(value)))
4368 if (event->attr.freq && value > sysctl_perf_event_sample_rate)
4371 event_function_call(event, __perf_event_period, &value);
4376 static const struct file_operations perf_fops;
4378 static inline int perf_fget_light(int fd, struct fd *p)
4380 struct fd f = fdget(fd);
4384 if (f.file->f_op != &perf_fops) {
4392 static int perf_event_set_output(struct perf_event *event,
4393 struct perf_event *output_event);
4394 static int perf_event_set_filter(struct perf_event *event, void __user *arg);
4395 static int perf_event_set_bpf_prog(struct perf_event *event, u32 prog_fd);
4397 static long _perf_ioctl(struct perf_event *event, unsigned int cmd, unsigned long arg)
4399 void (*func)(struct perf_event *);
4403 case PERF_EVENT_IOC_ENABLE:
4404 func = _perf_event_enable;
4406 case PERF_EVENT_IOC_DISABLE:
4407 func = _perf_event_disable;
4409 case PERF_EVENT_IOC_RESET:
4410 func = _perf_event_reset;
4413 case PERF_EVENT_IOC_REFRESH:
4414 return _perf_event_refresh(event, arg);
4416 case PERF_EVENT_IOC_PERIOD:
4417 return perf_event_period(event, (u64 __user *)arg);
4419 case PERF_EVENT_IOC_ID:
4421 u64 id = primary_event_id(event);
4423 if (copy_to_user((void __user *)arg, &id, sizeof(id)))
4428 case PERF_EVENT_IOC_SET_OUTPUT:
4432 struct perf_event *output_event;
4434 ret = perf_fget_light(arg, &output);
4437 output_event = output.file->private_data;
4438 ret = perf_event_set_output(event, output_event);
4441 ret = perf_event_set_output(event, NULL);
4446 case PERF_EVENT_IOC_SET_FILTER:
4447 return perf_event_set_filter(event, (void __user *)arg);
4449 case PERF_EVENT_IOC_SET_BPF:
4450 return perf_event_set_bpf_prog(event, arg);
4452 case PERF_EVENT_IOC_PAUSE_OUTPUT: {
4453 struct ring_buffer *rb;
4456 rb = rcu_dereference(event->rb);
4457 if (!rb || !rb->nr_pages) {
4461 rb_toggle_paused(rb, !!arg);
4469 if (flags & PERF_IOC_FLAG_GROUP)
4470 perf_event_for_each(event, func);
4472 perf_event_for_each_child(event, func);
4477 static long perf_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
4479 struct perf_event *event = file->private_data;
4480 struct perf_event_context *ctx;
4483 ctx = perf_event_ctx_lock(event);
4484 ret = _perf_ioctl(event, cmd, arg);
4485 perf_event_ctx_unlock(event, ctx);
4490 #ifdef CONFIG_COMPAT
4491 static long perf_compat_ioctl(struct file *file, unsigned int cmd,
4494 switch (_IOC_NR(cmd)) {
4495 case _IOC_NR(PERF_EVENT_IOC_SET_FILTER):
4496 case _IOC_NR(PERF_EVENT_IOC_ID):
4497 /* Fix up pointer size (usually 4 -> 8 in 32-on-64-bit case */
4498 if (_IOC_SIZE(cmd) == sizeof(compat_uptr_t)) {
4499 cmd &= ~IOCSIZE_MASK;
4500 cmd |= sizeof(void *) << IOCSIZE_SHIFT;
4504 return perf_ioctl(file, cmd, arg);
4507 # define perf_compat_ioctl NULL
4510 int perf_event_task_enable(void)
4512 struct perf_event_context *ctx;
4513 struct perf_event *event;
4515 mutex_lock(¤t->perf_event_mutex);
4516 list_for_each_entry(event, ¤t->perf_event_list, owner_entry) {
4517 ctx = perf_event_ctx_lock(event);
4518 perf_event_for_each_child(event, _perf_event_enable);
4519 perf_event_ctx_unlock(event, ctx);
4521 mutex_unlock(¤t->perf_event_mutex);
4526 int perf_event_task_disable(void)
4528 struct perf_event_context *ctx;
4529 struct perf_event *event;
4531 mutex_lock(¤t->perf_event_mutex);
4532 list_for_each_entry(event, ¤t->perf_event_list, owner_entry) {
4533 ctx = perf_event_ctx_lock(event);
4534 perf_event_for_each_child(event, _perf_event_disable);
4535 perf_event_ctx_unlock(event, ctx);
4537 mutex_unlock(¤t->perf_event_mutex);
4542 static int perf_event_index(struct perf_event *event)
4544 if (event->hw.state & PERF_HES_STOPPED)
4547 if (event->state != PERF_EVENT_STATE_ACTIVE)
4550 return event->pmu->event_idx(event);
4553 static void calc_timer_values(struct perf_event *event,
4560 *now = perf_clock();
4561 ctx_time = event->shadow_ctx_time + *now;
4562 *enabled = ctx_time - event->tstamp_enabled;
4563 *running = ctx_time - event->tstamp_running;
4566 static void perf_event_init_userpage(struct perf_event *event)
4568 struct perf_event_mmap_page *userpg;
4569 struct ring_buffer *rb;
4572 rb = rcu_dereference(event->rb);
4576 userpg = rb->user_page;
4578 /* Allow new userspace to detect that bit 0 is deprecated */
4579 userpg->cap_bit0_is_deprecated = 1;
4580 userpg->size = offsetof(struct perf_event_mmap_page, __reserved);
4581 userpg->data_offset = PAGE_SIZE;
4582 userpg->data_size = perf_data_size(rb);
4588 void __weak arch_perf_update_userpage(
4589 struct perf_event *event, struct perf_event_mmap_page *userpg, u64 now)
4594 * Callers need to ensure there can be no nesting of this function, otherwise
4595 * the seqlock logic goes bad. We can not serialize this because the arch
4596 * code calls this from NMI context.
4598 void perf_event_update_userpage(struct perf_event *event)
4600 struct perf_event_mmap_page *userpg;
4601 struct ring_buffer *rb;
4602 u64 enabled, running, now;
4605 rb = rcu_dereference(event->rb);
4610 * compute total_time_enabled, total_time_running
4611 * based on snapshot values taken when the event
4612 * was last scheduled in.
4614 * we cannot simply called update_context_time()
4615 * because of locking issue as we can be called in
4618 calc_timer_values(event, &now, &enabled, &running);
4620 userpg = rb->user_page;
4622 * Disable preemption so as to not let the corresponding user-space
4623 * spin too long if we get preempted.
4628 userpg->index = perf_event_index(event);
4629 userpg->offset = perf_event_count(event);
4631 userpg->offset -= local64_read(&event->hw.prev_count);
4633 userpg->time_enabled = enabled +
4634 atomic64_read(&event->child_total_time_enabled);
4636 userpg->time_running = running +
4637 atomic64_read(&event->child_total_time_running);
4639 arch_perf_update_userpage(event, userpg, now);
4648 static int perf_mmap_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
4650 struct perf_event *event = vma->vm_file->private_data;
4651 struct ring_buffer *rb;
4652 int ret = VM_FAULT_SIGBUS;
4654 if (vmf->flags & FAULT_FLAG_MKWRITE) {
4655 if (vmf->pgoff == 0)
4661 rb = rcu_dereference(event->rb);
4665 if (vmf->pgoff && (vmf->flags & FAULT_FLAG_WRITE))
4668 vmf->page = perf_mmap_to_page(rb, vmf->pgoff);
4672 get_page(vmf->page);
4673 vmf->page->mapping = vma->vm_file->f_mapping;
4674 vmf->page->index = vmf->pgoff;
4683 static void ring_buffer_attach(struct perf_event *event,
4684 struct ring_buffer *rb)
4686 struct ring_buffer *old_rb = NULL;
4687 unsigned long flags;
4691 * Should be impossible, we set this when removing
4692 * event->rb_entry and wait/clear when adding event->rb_entry.
4694 WARN_ON_ONCE(event->rcu_pending);
4697 spin_lock_irqsave(&old_rb->event_lock, flags);
4698 list_del_rcu(&event->rb_entry);
4699 spin_unlock_irqrestore(&old_rb->event_lock, flags);
4701 event->rcu_batches = get_state_synchronize_rcu();
4702 event->rcu_pending = 1;
4706 if (event->rcu_pending) {
4707 cond_synchronize_rcu(event->rcu_batches);
4708 event->rcu_pending = 0;
4711 spin_lock_irqsave(&rb->event_lock, flags);
4712 list_add_rcu(&event->rb_entry, &rb->event_list);
4713 spin_unlock_irqrestore(&rb->event_lock, flags);
4716 rcu_assign_pointer(event->rb, rb);
4719 ring_buffer_put(old_rb);
4721 * Since we detached before setting the new rb, so that we
4722 * could attach the new rb, we could have missed a wakeup.
4725 wake_up_all(&event->waitq);
4729 static void ring_buffer_wakeup(struct perf_event *event)
4731 struct ring_buffer *rb;
4734 rb = rcu_dereference(event->rb);
4736 list_for_each_entry_rcu(event, &rb->event_list, rb_entry)
4737 wake_up_all(&event->waitq);
4742 struct ring_buffer *ring_buffer_get(struct perf_event *event)
4744 struct ring_buffer *rb;
4747 rb = rcu_dereference(event->rb);
4749 if (!atomic_inc_not_zero(&rb->refcount))
4757 void ring_buffer_put(struct ring_buffer *rb)
4759 if (!atomic_dec_and_test(&rb->refcount))
4762 WARN_ON_ONCE(!list_empty(&rb->event_list));
4764 call_rcu(&rb->rcu_head, rb_free_rcu);
4767 static void perf_mmap_open(struct vm_area_struct *vma)
4769 struct perf_event *event = vma->vm_file->private_data;
4771 atomic_inc(&event->mmap_count);
4772 atomic_inc(&event->rb->mmap_count);
4775 atomic_inc(&event->rb->aux_mmap_count);
4777 if (event->pmu->event_mapped)
4778 event->pmu->event_mapped(event);
4781 static void perf_pmu_output_stop(struct perf_event *event);
4784 * A buffer can be mmap()ed multiple times; either directly through the same
4785 * event, or through other events by use of perf_event_set_output().
4787 * In order to undo the VM accounting done by perf_mmap() we need to destroy
4788 * the buffer here, where we still have a VM context. This means we need
4789 * to detach all events redirecting to us.
4791 static void perf_mmap_close(struct vm_area_struct *vma)
4793 struct perf_event *event = vma->vm_file->private_data;
4795 struct ring_buffer *rb = ring_buffer_get(event);
4796 struct user_struct *mmap_user = rb->mmap_user;
4797 int mmap_locked = rb->mmap_locked;
4798 unsigned long size = perf_data_size(rb);
4800 if (event->pmu->event_unmapped)
4801 event->pmu->event_unmapped(event);
4804 * rb->aux_mmap_count will always drop before rb->mmap_count and
4805 * event->mmap_count, so it is ok to use event->mmap_mutex to
4806 * serialize with perf_mmap here.
4808 if (rb_has_aux(rb) && vma->vm_pgoff == rb->aux_pgoff &&
4809 atomic_dec_and_mutex_lock(&rb->aux_mmap_count, &event->mmap_mutex)) {
4811 * Stop all AUX events that are writing to this buffer,
4812 * so that we can free its AUX pages and corresponding PMU
4813 * data. Note that after rb::aux_mmap_count dropped to zero,
4814 * they won't start any more (see perf_aux_output_begin()).
4816 perf_pmu_output_stop(event);
4818 /* now it's safe to free the pages */
4819 atomic_long_sub(rb->aux_nr_pages, &mmap_user->locked_vm);
4820 vma->vm_mm->pinned_vm -= rb->aux_mmap_locked;
4822 /* this has to be the last one */
4824 WARN_ON_ONCE(atomic_read(&rb->aux_refcount));
4826 mutex_unlock(&event->mmap_mutex);
4829 atomic_dec(&rb->mmap_count);
4831 if (!atomic_dec_and_mutex_lock(&event->mmap_count, &event->mmap_mutex))
4834 ring_buffer_attach(event, NULL);
4835 mutex_unlock(&event->mmap_mutex);
4837 /* If there's still other mmap()s of this buffer, we're done. */
4838 if (atomic_read(&rb->mmap_count))
4842 * No other mmap()s, detach from all other events that might redirect
4843 * into the now unreachable buffer. Somewhat complicated by the
4844 * fact that rb::event_lock otherwise nests inside mmap_mutex.
4848 list_for_each_entry_rcu(event, &rb->event_list, rb_entry) {
4849 if (!atomic_long_inc_not_zero(&event->refcount)) {
4851 * This event is en-route to free_event() which will
4852 * detach it and remove it from the list.
4858 mutex_lock(&event->mmap_mutex);
4860 * Check we didn't race with perf_event_set_output() which can
4861 * swizzle the rb from under us while we were waiting to
4862 * acquire mmap_mutex.
4864 * If we find a different rb; ignore this event, a next
4865 * iteration will no longer find it on the list. We have to
4866 * still restart the iteration to make sure we're not now
4867 * iterating the wrong list.
4869 if (event->rb == rb)
4870 ring_buffer_attach(event, NULL);
4872 mutex_unlock(&event->mmap_mutex);
4876 * Restart the iteration; either we're on the wrong list or
4877 * destroyed its integrity by doing a deletion.
4884 * It could be there's still a few 0-ref events on the list; they'll
4885 * get cleaned up by free_event() -- they'll also still have their
4886 * ref on the rb and will free it whenever they are done with it.
4888 * Aside from that, this buffer is 'fully' detached and unmapped,
4889 * undo the VM accounting.
4892 atomic_long_sub((size >> PAGE_SHIFT) + 1, &mmap_user->locked_vm);
4893 vma->vm_mm->pinned_vm -= mmap_locked;
4894 free_uid(mmap_user);
4897 ring_buffer_put(rb); /* could be last */
4900 static const struct vm_operations_struct perf_mmap_vmops = {
4901 .open = perf_mmap_open,
4902 .close = perf_mmap_close, /* non mergable */
4903 .fault = perf_mmap_fault,
4904 .page_mkwrite = perf_mmap_fault,
4907 static int perf_mmap(struct file *file, struct vm_area_struct *vma)
4909 struct perf_event *event = file->private_data;
4910 unsigned long user_locked, user_lock_limit;
4911 struct user_struct *user = current_user();
4912 unsigned long locked, lock_limit;
4913 struct ring_buffer *rb = NULL;
4914 unsigned long vma_size;
4915 unsigned long nr_pages;
4916 long user_extra = 0, extra = 0;
4917 int ret = 0, flags = 0;
4920 * Don't allow mmap() of inherited per-task counters. This would
4921 * create a performance issue due to all children writing to the
4924 if (event->cpu == -1 && event->attr.inherit)
4927 if (!(vma->vm_flags & VM_SHARED))
4930 vma_size = vma->vm_end - vma->vm_start;
4932 if (vma->vm_pgoff == 0) {
4933 nr_pages = (vma_size / PAGE_SIZE) - 1;
4936 * AUX area mapping: if rb->aux_nr_pages != 0, it's already
4937 * mapped, all subsequent mappings should have the same size
4938 * and offset. Must be above the normal perf buffer.
4940 u64 aux_offset, aux_size;
4945 nr_pages = vma_size / PAGE_SIZE;
4947 mutex_lock(&event->mmap_mutex);
4954 aux_offset = ACCESS_ONCE(rb->user_page->aux_offset);
4955 aux_size = ACCESS_ONCE(rb->user_page->aux_size);
4957 if (aux_offset < perf_data_size(rb) + PAGE_SIZE)
4960 if (aux_offset != vma->vm_pgoff << PAGE_SHIFT)
4963 /* already mapped with a different offset */
4964 if (rb_has_aux(rb) && rb->aux_pgoff != vma->vm_pgoff)
4967 if (aux_size != vma_size || aux_size != nr_pages * PAGE_SIZE)
4970 /* already mapped with a different size */
4971 if (rb_has_aux(rb) && rb->aux_nr_pages != nr_pages)
4974 if (!is_power_of_2(nr_pages))
4977 if (!atomic_inc_not_zero(&rb->mmap_count))
4980 if (rb_has_aux(rb)) {
4981 atomic_inc(&rb->aux_mmap_count);
4986 atomic_set(&rb->aux_mmap_count, 1);
4987 user_extra = nr_pages;
4993 * If we have rb pages ensure they're a power-of-two number, so we
4994 * can do bitmasks instead of modulo.
4996 if (nr_pages != 0 && !is_power_of_2(nr_pages))
4999 if (vma_size != PAGE_SIZE * (1 + nr_pages))
5002 WARN_ON_ONCE(event->ctx->parent_ctx);
5004 mutex_lock(&event->mmap_mutex);
5006 if (event->rb->nr_pages != nr_pages) {
5011 if (!atomic_inc_not_zero(&event->rb->mmap_count)) {
5013 * Raced against perf_mmap_close() through
5014 * perf_event_set_output(). Try again, hope for better
5017 mutex_unlock(&event->mmap_mutex);
5024 user_extra = nr_pages + 1;
5027 user_lock_limit = sysctl_perf_event_mlock >> (PAGE_SHIFT - 10);
5030 * Increase the limit linearly with more CPUs:
5032 user_lock_limit *= num_online_cpus();
5034 user_locked = atomic_long_read(&user->locked_vm) + user_extra;
5036 if (user_locked > user_lock_limit)
5037 extra = user_locked - user_lock_limit;
5039 lock_limit = rlimit(RLIMIT_MEMLOCK);
5040 lock_limit >>= PAGE_SHIFT;
5041 locked = vma->vm_mm->pinned_vm + extra;
5043 if ((locked > lock_limit) && perf_paranoid_tracepoint_raw() &&
5044 !capable(CAP_IPC_LOCK)) {
5049 WARN_ON(!rb && event->rb);
5051 if (vma->vm_flags & VM_WRITE)
5052 flags |= RING_BUFFER_WRITABLE;
5055 rb = rb_alloc(nr_pages,
5056 event->attr.watermark ? event->attr.wakeup_watermark : 0,
5064 atomic_set(&rb->mmap_count, 1);
5065 rb->mmap_user = get_current_user();
5066 rb->mmap_locked = extra;
5068 ring_buffer_attach(event, rb);
5070 perf_event_init_userpage(event);
5071 perf_event_update_userpage(event);
5073 ret = rb_alloc_aux(rb, event, vma->vm_pgoff, nr_pages,
5074 event->attr.aux_watermark, flags);
5076 rb->aux_mmap_locked = extra;
5081 atomic_long_add(user_extra, &user->locked_vm);
5082 vma->vm_mm->pinned_vm += extra;
5084 atomic_inc(&event->mmap_count);
5086 atomic_dec(&rb->mmap_count);
5089 mutex_unlock(&event->mmap_mutex);
5092 * Since pinned accounting is per vm we cannot allow fork() to copy our
5095 vma->vm_flags |= VM_DONTCOPY | VM_DONTEXPAND | VM_DONTDUMP;
5096 vma->vm_ops = &perf_mmap_vmops;
5098 if (event->pmu->event_mapped)
5099 event->pmu->event_mapped(event);
5104 static int perf_fasync(int fd, struct file *filp, int on)
5106 struct inode *inode = file_inode(filp);
5107 struct perf_event *event = filp->private_data;
5111 retval = fasync_helper(fd, filp, on, &event->fasync);
5112 inode_unlock(inode);
5120 static const struct file_operations perf_fops = {
5121 .llseek = no_llseek,
5122 .release = perf_release,
5125 .unlocked_ioctl = perf_ioctl,
5126 .compat_ioctl = perf_compat_ioctl,
5128 .fasync = perf_fasync,
5134 * If there's data, ensure we set the poll() state and publish everything
5135 * to user-space before waking everybody up.
5138 static inline struct fasync_struct **perf_event_fasync(struct perf_event *event)
5140 /* only the parent has fasync state */
5142 event = event->parent;
5143 return &event->fasync;
5146 void perf_event_wakeup(struct perf_event *event)
5148 ring_buffer_wakeup(event);
5150 if (event->pending_kill) {
5151 kill_fasync(perf_event_fasync(event), SIGIO, event->pending_kill);
5152 event->pending_kill = 0;
5156 static void perf_pending_event(struct irq_work *entry)
5158 struct perf_event *event = container_of(entry,
5159 struct perf_event, pending);
5162 rctx = perf_swevent_get_recursion_context();
5164 * If we 'fail' here, that's OK, it means recursion is already disabled
5165 * and we won't recurse 'further'.
5168 if (event->pending_disable) {
5169 event->pending_disable = 0;
5170 perf_event_disable_local(event);
5173 if (event->pending_wakeup) {
5174 event->pending_wakeup = 0;
5175 perf_event_wakeup(event);
5179 perf_swevent_put_recursion_context(rctx);
5183 * We assume there is only KVM supporting the callbacks.
5184 * Later on, we might change it to a list if there is
5185 * another virtualization implementation supporting the callbacks.
5187 struct perf_guest_info_callbacks *perf_guest_cbs;
5189 int perf_register_guest_info_callbacks(struct perf_guest_info_callbacks *cbs)
5191 perf_guest_cbs = cbs;
5194 EXPORT_SYMBOL_GPL(perf_register_guest_info_callbacks);
5196 int perf_unregister_guest_info_callbacks(struct perf_guest_info_callbacks *cbs)
5198 perf_guest_cbs = NULL;
5201 EXPORT_SYMBOL_GPL(perf_unregister_guest_info_callbacks);
5204 perf_output_sample_regs(struct perf_output_handle *handle,
5205 struct pt_regs *regs, u64 mask)
5209 for_each_set_bit(bit, (const unsigned long *) &mask,
5210 sizeof(mask) * BITS_PER_BYTE) {
5213 val = perf_reg_value(regs, bit);
5214 perf_output_put(handle, val);
5218 static void perf_sample_regs_user(struct perf_regs *regs_user,
5219 struct pt_regs *regs,
5220 struct pt_regs *regs_user_copy)
5222 if (user_mode(regs)) {
5223 regs_user->abi = perf_reg_abi(current);
5224 regs_user->regs = regs;
5225 } else if (current->mm) {
5226 perf_get_regs_user(regs_user, regs, regs_user_copy);
5228 regs_user->abi = PERF_SAMPLE_REGS_ABI_NONE;
5229 regs_user->regs = NULL;
5233 static void perf_sample_regs_intr(struct perf_regs *regs_intr,
5234 struct pt_regs *regs)
5236 regs_intr->regs = regs;
5237 regs_intr->abi = perf_reg_abi(current);
5242 * Get remaining task size from user stack pointer.
5244 * It'd be better to take stack vma map and limit this more
5245 * precisly, but there's no way to get it safely under interrupt,
5246 * so using TASK_SIZE as limit.
5248 static u64 perf_ustack_task_size(struct pt_regs *regs)
5250 unsigned long addr = perf_user_stack_pointer(regs);
5252 if (!addr || addr >= TASK_SIZE)
5255 return TASK_SIZE - addr;
5259 perf_sample_ustack_size(u16 stack_size, u16 header_size,
5260 struct pt_regs *regs)
5264 /* No regs, no stack pointer, no dump. */
5269 * Check if we fit in with the requested stack size into the:
5271 * If we don't, we limit the size to the TASK_SIZE.
5273 * - remaining sample size
5274 * If we don't, we customize the stack size to
5275 * fit in to the remaining sample size.
5278 task_size = min((u64) USHRT_MAX, perf_ustack_task_size(regs));
5279 stack_size = min(stack_size, (u16) task_size);
5281 /* Current header size plus static size and dynamic size. */
5282 header_size += 2 * sizeof(u64);
5284 /* Do we fit in with the current stack dump size? */
5285 if ((u16) (header_size + stack_size) < header_size) {
5287 * If we overflow the maximum size for the sample,
5288 * we customize the stack dump size to fit in.
5290 stack_size = USHRT_MAX - header_size - sizeof(u64);
5291 stack_size = round_up(stack_size, sizeof(u64));
5298 perf_output_sample_ustack(struct perf_output_handle *handle, u64 dump_size,
5299 struct pt_regs *regs)
5301 /* Case of a kernel thread, nothing to dump */
5304 perf_output_put(handle, size);
5313 * - the size requested by user or the best one we can fit
5314 * in to the sample max size
5316 * - user stack dump data
5318 * - the actual dumped size
5322 perf_output_put(handle, dump_size);
5325 sp = perf_user_stack_pointer(regs);
5326 rem = __output_copy_user(handle, (void *) sp, dump_size);
5327 dyn_size = dump_size - rem;
5329 perf_output_skip(handle, rem);
5332 perf_output_put(handle, dyn_size);
5336 static void __perf_event_header__init_id(struct perf_event_header *header,
5337 struct perf_sample_data *data,
5338 struct perf_event *event)
5340 u64 sample_type = event->attr.sample_type;
5342 data->type = sample_type;
5343 header->size += event->id_header_size;
5345 if (sample_type & PERF_SAMPLE_TID) {
5346 /* namespace issues */
5347 data->tid_entry.pid = perf_event_pid(event, current);
5348 data->tid_entry.tid = perf_event_tid(event, current);
5351 if (sample_type & PERF_SAMPLE_TIME)
5352 data->time = perf_event_clock(event);
5354 if (sample_type & (PERF_SAMPLE_ID | PERF_SAMPLE_IDENTIFIER))
5355 data->id = primary_event_id(event);
5357 if (sample_type & PERF_SAMPLE_STREAM_ID)
5358 data->stream_id = event->id;
5360 if (sample_type & PERF_SAMPLE_CPU) {
5361 data->cpu_entry.cpu = raw_smp_processor_id();
5362 data->cpu_entry.reserved = 0;
5366 void perf_event_header__init_id(struct perf_event_header *header,
5367 struct perf_sample_data *data,
5368 struct perf_event *event)
5370 if (event->attr.sample_id_all)
5371 __perf_event_header__init_id(header, data, event);
5374 static void __perf_event__output_id_sample(struct perf_output_handle *handle,
5375 struct perf_sample_data *data)
5377 u64 sample_type = data->type;
5379 if (sample_type & PERF_SAMPLE_TID)
5380 perf_output_put(handle, data->tid_entry);
5382 if (sample_type & PERF_SAMPLE_TIME)
5383 perf_output_put(handle, data->time);
5385 if (sample_type & PERF_SAMPLE_ID)
5386 perf_output_put(handle, data->id);
5388 if (sample_type & PERF_SAMPLE_STREAM_ID)
5389 perf_output_put(handle, data->stream_id);
5391 if (sample_type & PERF_SAMPLE_CPU)
5392 perf_output_put(handle, data->cpu_entry);
5394 if (sample_type & PERF_SAMPLE_IDENTIFIER)
5395 perf_output_put(handle, data->id);
5398 void perf_event__output_id_sample(struct perf_event *event,
5399 struct perf_output_handle *handle,
5400 struct perf_sample_data *sample)
5402 if (event->attr.sample_id_all)
5403 __perf_event__output_id_sample(handle, sample);
5406 static void perf_output_read_one(struct perf_output_handle *handle,
5407 struct perf_event *event,
5408 u64 enabled, u64 running)
5410 u64 read_format = event->attr.read_format;
5414 values[n++] = perf_event_count(event);
5415 if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED) {
5416 values[n++] = enabled +
5417 atomic64_read(&event->child_total_time_enabled);
5419 if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING) {
5420 values[n++] = running +
5421 atomic64_read(&event->child_total_time_running);
5423 if (read_format & PERF_FORMAT_ID)
5424 values[n++] = primary_event_id(event);
5426 __output_copy(handle, values, n * sizeof(u64));
5430 * XXX PERF_FORMAT_GROUP vs inherited events seems difficult.
5432 static void perf_output_read_group(struct perf_output_handle *handle,
5433 struct perf_event *event,
5434 u64 enabled, u64 running)
5436 struct perf_event *leader = event->group_leader, *sub;
5437 u64 read_format = event->attr.read_format;
5441 values[n++] = 1 + leader->nr_siblings;
5443 if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED)
5444 values[n++] = enabled;
5446 if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING)
5447 values[n++] = running;
5449 if (leader != event)
5450 leader->pmu->read(leader);
5452 values[n++] = perf_event_count(leader);
5453 if (read_format & PERF_FORMAT_ID)
5454 values[n++] = primary_event_id(leader);
5456 __output_copy(handle, values, n * sizeof(u64));
5458 list_for_each_entry(sub, &leader->sibling_list, group_entry) {
5461 if ((sub != event) &&
5462 (sub->state == PERF_EVENT_STATE_ACTIVE))
5463 sub->pmu->read(sub);
5465 values[n++] = perf_event_count(sub);
5466 if (read_format & PERF_FORMAT_ID)
5467 values[n++] = primary_event_id(sub);
5469 __output_copy(handle, values, n * sizeof(u64));
5473 #define PERF_FORMAT_TOTAL_TIMES (PERF_FORMAT_TOTAL_TIME_ENABLED|\
5474 PERF_FORMAT_TOTAL_TIME_RUNNING)
5476 static void perf_output_read(struct perf_output_handle *handle,
5477 struct perf_event *event)
5479 u64 enabled = 0, running = 0, now;
5480 u64 read_format = event->attr.read_format;
5483 * compute total_time_enabled, total_time_running
5484 * based on snapshot values taken when the event
5485 * was last scheduled in.
5487 * we cannot simply called update_context_time()
5488 * because of locking issue as we are called in
5491 if (read_format & PERF_FORMAT_TOTAL_TIMES)
5492 calc_timer_values(event, &now, &enabled, &running);
5494 if (event->attr.read_format & PERF_FORMAT_GROUP)
5495 perf_output_read_group(handle, event, enabled, running);
5497 perf_output_read_one(handle, event, enabled, running);
5500 void perf_output_sample(struct perf_output_handle *handle,
5501 struct perf_event_header *header,
5502 struct perf_sample_data *data,
5503 struct perf_event *event)
5505 u64 sample_type = data->type;
5507 perf_output_put(handle, *header);
5509 if (sample_type & PERF_SAMPLE_IDENTIFIER)
5510 perf_output_put(handle, data->id);
5512 if (sample_type & PERF_SAMPLE_IP)
5513 perf_output_put(handle, data->ip);
5515 if (sample_type & PERF_SAMPLE_TID)
5516 perf_output_put(handle, data->tid_entry);
5518 if (sample_type & PERF_SAMPLE_TIME)
5519 perf_output_put(handle, data->time);
5521 if (sample_type & PERF_SAMPLE_ADDR)
5522 perf_output_put(handle, data->addr);
5524 if (sample_type & PERF_SAMPLE_ID)
5525 perf_output_put(handle, data->id);
5527 if (sample_type & PERF_SAMPLE_STREAM_ID)
5528 perf_output_put(handle, data->stream_id);
5530 if (sample_type & PERF_SAMPLE_CPU)
5531 perf_output_put(handle, data->cpu_entry);
5533 if (sample_type & PERF_SAMPLE_PERIOD)
5534 perf_output_put(handle, data->period);
5536 if (sample_type & PERF_SAMPLE_READ)
5537 perf_output_read(handle, event);
5539 if (sample_type & PERF_SAMPLE_CALLCHAIN) {
5540 if (data->callchain) {
5543 if (data->callchain)
5544 size += data->callchain->nr;
5546 size *= sizeof(u64);
5548 __output_copy(handle, data->callchain, size);
5551 perf_output_put(handle, nr);
5555 if (sample_type & PERF_SAMPLE_RAW) {
5557 u32 raw_size = data->raw->size;
5558 u32 real_size = round_up(raw_size + sizeof(u32),
5559 sizeof(u64)) - sizeof(u32);
5562 perf_output_put(handle, real_size);
5563 __output_copy(handle, data->raw->data, raw_size);
5564 if (real_size - raw_size)
5565 __output_copy(handle, &zero, real_size - raw_size);
5571 .size = sizeof(u32),
5574 perf_output_put(handle, raw);
5578 if (sample_type & PERF_SAMPLE_BRANCH_STACK) {
5579 if (data->br_stack) {
5582 size = data->br_stack->nr
5583 * sizeof(struct perf_branch_entry);
5585 perf_output_put(handle, data->br_stack->nr);
5586 perf_output_copy(handle, data->br_stack->entries, size);
5589 * we always store at least the value of nr
5592 perf_output_put(handle, nr);
5596 if (sample_type & PERF_SAMPLE_REGS_USER) {
5597 u64 abi = data->regs_user.abi;
5600 * If there are no regs to dump, notice it through
5601 * first u64 being zero (PERF_SAMPLE_REGS_ABI_NONE).
5603 perf_output_put(handle, abi);
5606 u64 mask = event->attr.sample_regs_user;
5607 perf_output_sample_regs(handle,
5608 data->regs_user.regs,
5613 if (sample_type & PERF_SAMPLE_STACK_USER) {
5614 perf_output_sample_ustack(handle,
5615 data->stack_user_size,
5616 data->regs_user.regs);
5619 if (sample_type & PERF_SAMPLE_WEIGHT)
5620 perf_output_put(handle, data->weight);
5622 if (sample_type & PERF_SAMPLE_DATA_SRC)
5623 perf_output_put(handle, data->data_src.val);
5625 if (sample_type & PERF_SAMPLE_TRANSACTION)
5626 perf_output_put(handle, data->txn);
5628 if (sample_type & PERF_SAMPLE_REGS_INTR) {
5629 u64 abi = data->regs_intr.abi;
5631 * If there are no regs to dump, notice it through
5632 * first u64 being zero (PERF_SAMPLE_REGS_ABI_NONE).
5634 perf_output_put(handle, abi);
5637 u64 mask = event->attr.sample_regs_intr;
5639 perf_output_sample_regs(handle,
5640 data->regs_intr.regs,
5645 if (!event->attr.watermark) {
5646 int wakeup_events = event->attr.wakeup_events;
5648 if (wakeup_events) {
5649 struct ring_buffer *rb = handle->rb;
5650 int events = local_inc_return(&rb->events);
5652 if (events >= wakeup_events) {
5653 local_sub(wakeup_events, &rb->events);
5654 local_inc(&rb->wakeup);
5660 void perf_prepare_sample(struct perf_event_header *header,
5661 struct perf_sample_data *data,
5662 struct perf_event *event,
5663 struct pt_regs *regs)
5665 u64 sample_type = event->attr.sample_type;
5667 header->type = PERF_RECORD_SAMPLE;
5668 header->size = sizeof(*header) + event->header_size;
5671 header->misc |= perf_misc_flags(regs);
5673 __perf_event_header__init_id(header, data, event);
5675 if (sample_type & PERF_SAMPLE_IP)
5676 data->ip = perf_instruction_pointer(regs);
5678 if (sample_type & PERF_SAMPLE_CALLCHAIN) {
5681 data->callchain = perf_callchain(event, regs);
5683 if (data->callchain)
5684 size += data->callchain->nr;
5686 header->size += size * sizeof(u64);
5689 if (sample_type & PERF_SAMPLE_RAW) {
5690 int size = sizeof(u32);
5693 size += data->raw->size;
5695 size += sizeof(u32);
5697 header->size += round_up(size, sizeof(u64));
5700 if (sample_type & PERF_SAMPLE_BRANCH_STACK) {
5701 int size = sizeof(u64); /* nr */
5702 if (data->br_stack) {
5703 size += data->br_stack->nr
5704 * sizeof(struct perf_branch_entry);
5706 header->size += size;
5709 if (sample_type & (PERF_SAMPLE_REGS_USER | PERF_SAMPLE_STACK_USER))
5710 perf_sample_regs_user(&data->regs_user, regs,
5711 &data->regs_user_copy);
5713 if (sample_type & PERF_SAMPLE_REGS_USER) {
5714 /* regs dump ABI info */
5715 int size = sizeof(u64);
5717 if (data->regs_user.regs) {
5718 u64 mask = event->attr.sample_regs_user;
5719 size += hweight64(mask) * sizeof(u64);
5722 header->size += size;
5725 if (sample_type & PERF_SAMPLE_STACK_USER) {
5727 * Either we need PERF_SAMPLE_STACK_USER bit to be allways
5728 * processed as the last one or have additional check added
5729 * in case new sample type is added, because we could eat
5730 * up the rest of the sample size.
5732 u16 stack_size = event->attr.sample_stack_user;
5733 u16 size = sizeof(u64);
5735 stack_size = perf_sample_ustack_size(stack_size, header->size,
5736 data->regs_user.regs);
5739 * If there is something to dump, add space for the dump
5740 * itself and for the field that tells the dynamic size,
5741 * which is how many have been actually dumped.
5744 size += sizeof(u64) + stack_size;
5746 data->stack_user_size = stack_size;
5747 header->size += size;
5750 if (sample_type & PERF_SAMPLE_REGS_INTR) {
5751 /* regs dump ABI info */
5752 int size = sizeof(u64);
5754 perf_sample_regs_intr(&data->regs_intr, regs);
5756 if (data->regs_intr.regs) {
5757 u64 mask = event->attr.sample_regs_intr;
5759 size += hweight64(mask) * sizeof(u64);
5762 header->size += size;
5766 static void __always_inline
5767 __perf_event_output(struct perf_event *event,
5768 struct perf_sample_data *data,
5769 struct pt_regs *regs,
5770 int (*output_begin)(struct perf_output_handle *,
5771 struct perf_event *,
5774 struct perf_output_handle handle;
5775 struct perf_event_header header;
5777 /* protect the callchain buffers */
5780 perf_prepare_sample(&header, data, event, regs);
5782 if (output_begin(&handle, event, header.size))
5785 perf_output_sample(&handle, &header, data, event);
5787 perf_output_end(&handle);
5794 perf_event_output_forward(struct perf_event *event,
5795 struct perf_sample_data *data,
5796 struct pt_regs *regs)
5798 __perf_event_output(event, data, regs, perf_output_begin_forward);
5802 perf_event_output_backward(struct perf_event *event,
5803 struct perf_sample_data *data,
5804 struct pt_regs *regs)
5806 __perf_event_output(event, data, regs, perf_output_begin_backward);
5810 perf_event_output(struct perf_event *event,
5811 struct perf_sample_data *data,
5812 struct pt_regs *regs)
5814 __perf_event_output(event, data, regs, perf_output_begin);
5821 struct perf_read_event {
5822 struct perf_event_header header;
5829 perf_event_read_event(struct perf_event *event,
5830 struct task_struct *task)
5832 struct perf_output_handle handle;
5833 struct perf_sample_data sample;
5834 struct perf_read_event read_event = {
5836 .type = PERF_RECORD_READ,
5838 .size = sizeof(read_event) + event->read_size,
5840 .pid = perf_event_pid(event, task),
5841 .tid = perf_event_tid(event, task),
5845 perf_event_header__init_id(&read_event.header, &sample, event);
5846 ret = perf_output_begin(&handle, event, read_event.header.size);
5850 perf_output_put(&handle, read_event);
5851 perf_output_read(&handle, event);
5852 perf_event__output_id_sample(event, &handle, &sample);
5854 perf_output_end(&handle);
5857 typedef void (perf_event_aux_output_cb)(struct perf_event *event, void *data);
5860 perf_event_aux_ctx(struct perf_event_context *ctx,
5861 perf_event_aux_output_cb output,
5862 void *data, bool all)
5864 struct perf_event *event;
5866 list_for_each_entry_rcu(event, &ctx->event_list, event_entry) {
5868 if (event->state < PERF_EVENT_STATE_INACTIVE)
5870 if (!event_filter_match(event))
5874 output(event, data);
5879 perf_event_aux_task_ctx(perf_event_aux_output_cb output, void *data,
5880 struct perf_event_context *task_ctx)
5884 perf_event_aux_ctx(task_ctx, output, data, false);
5890 perf_event_aux(perf_event_aux_output_cb output, void *data,
5891 struct perf_event_context *task_ctx)
5893 struct perf_cpu_context *cpuctx;
5894 struct perf_event_context *ctx;
5899 * If we have task_ctx != NULL we only notify
5900 * the task context itself. The task_ctx is set
5901 * only for EXIT events before releasing task
5905 perf_event_aux_task_ctx(output, data, task_ctx);
5910 list_for_each_entry_rcu(pmu, &pmus, entry) {
5911 cpuctx = get_cpu_ptr(pmu->pmu_cpu_context);
5912 if (cpuctx->unique_pmu != pmu)
5914 perf_event_aux_ctx(&cpuctx->ctx, output, data, false);
5915 ctxn = pmu->task_ctx_nr;
5918 ctx = rcu_dereference(current->perf_event_ctxp[ctxn]);
5920 perf_event_aux_ctx(ctx, output, data, false);
5922 put_cpu_ptr(pmu->pmu_cpu_context);
5928 * Clear all file-based filters at exec, they'll have to be
5929 * re-instated when/if these objects are mmapped again.
5931 static void perf_event_addr_filters_exec(struct perf_event *event, void *data)
5933 struct perf_addr_filters_head *ifh = perf_event_addr_filters(event);
5934 struct perf_addr_filter *filter;
5935 unsigned int restart = 0, count = 0;
5936 unsigned long flags;
5938 if (!has_addr_filter(event))
5941 raw_spin_lock_irqsave(&ifh->lock, flags);
5942 list_for_each_entry(filter, &ifh->list, entry) {
5943 if (filter->inode) {
5944 event->addr_filters_offs[count] = 0;
5952 event->addr_filters_gen++;
5953 raw_spin_unlock_irqrestore(&ifh->lock, flags);
5956 perf_event_restart(event);
5959 void perf_event_exec(void)
5961 struct perf_event_context *ctx;
5965 for_each_task_context_nr(ctxn) {
5966 ctx = current->perf_event_ctxp[ctxn];
5970 perf_event_enable_on_exec(ctxn);
5972 perf_event_aux_ctx(ctx, perf_event_addr_filters_exec, NULL,
5978 struct remote_output {
5979 struct ring_buffer *rb;
5983 static void __perf_event_output_stop(struct perf_event *event, void *data)
5985 struct perf_event *parent = event->parent;
5986 struct remote_output *ro = data;
5987 struct ring_buffer *rb = ro->rb;
5988 struct stop_event_data sd = {
5992 if (!has_aux(event))
5999 * In case of inheritance, it will be the parent that links to the
6000 * ring-buffer, but it will be the child that's actually using it:
6002 if (rcu_dereference(parent->rb) == rb)
6003 ro->err = __perf_event_stop(&sd);
6006 static int __perf_pmu_output_stop(void *info)
6008 struct perf_event *event = info;
6009 struct pmu *pmu = event->pmu;
6010 struct perf_cpu_context *cpuctx = get_cpu_ptr(pmu->pmu_cpu_context);
6011 struct remote_output ro = {
6016 perf_event_aux_ctx(&cpuctx->ctx, __perf_event_output_stop, &ro, false);
6017 if (cpuctx->task_ctx)
6018 perf_event_aux_ctx(cpuctx->task_ctx, __perf_event_output_stop,
6025 static void perf_pmu_output_stop(struct perf_event *event)
6027 struct perf_event *iter;
6032 list_for_each_entry_rcu(iter, &event->rb->event_list, rb_entry) {
6034 * For per-CPU events, we need to make sure that neither they
6035 * nor their children are running; for cpu==-1 events it's
6036 * sufficient to stop the event itself if it's active, since
6037 * it can't have children.
6041 cpu = READ_ONCE(iter->oncpu);
6046 err = cpu_function_call(cpu, __perf_pmu_output_stop, event);
6047 if (err == -EAGAIN) {
6056 * task tracking -- fork/exit
6058 * enabled by: attr.comm | attr.mmap | attr.mmap2 | attr.mmap_data | attr.task
6061 struct perf_task_event {
6062 struct task_struct *task;
6063 struct perf_event_context *task_ctx;
6066 struct perf_event_header header;
6076 static int perf_event_task_match(struct perf_event *event)
6078 return event->attr.comm || event->attr.mmap ||
6079 event->attr.mmap2 || event->attr.mmap_data ||
6083 static void perf_event_task_output(struct perf_event *event,
6086 struct perf_task_event *task_event = data;
6087 struct perf_output_handle handle;
6088 struct perf_sample_data sample;
6089 struct task_struct *task = task_event->task;
6090 int ret, size = task_event->event_id.header.size;
6092 if (!perf_event_task_match(event))
6095 perf_event_header__init_id(&task_event->event_id.header, &sample, event);
6097 ret = perf_output_begin(&handle, event,
6098 task_event->event_id.header.size);
6102 task_event->event_id.pid = perf_event_pid(event, task);
6103 task_event->event_id.ppid = perf_event_pid(event, current);
6105 task_event->event_id.tid = perf_event_tid(event, task);
6106 task_event->event_id.ptid = perf_event_tid(event, current);
6108 task_event->event_id.time = perf_event_clock(event);
6110 perf_output_put(&handle, task_event->event_id);
6112 perf_event__output_id_sample(event, &handle, &sample);
6114 perf_output_end(&handle);
6116 task_event->event_id.header.size = size;
6119 static void perf_event_task(struct task_struct *task,
6120 struct perf_event_context *task_ctx,
6123 struct perf_task_event task_event;
6125 if (!atomic_read(&nr_comm_events) &&
6126 !atomic_read(&nr_mmap_events) &&
6127 !atomic_read(&nr_task_events))
6130 task_event = (struct perf_task_event){
6132 .task_ctx = task_ctx,
6135 .type = new ? PERF_RECORD_FORK : PERF_RECORD_EXIT,
6137 .size = sizeof(task_event.event_id),
6147 perf_event_aux(perf_event_task_output,
6152 void perf_event_fork(struct task_struct *task)
6154 perf_event_task(task, NULL, 1);
6161 struct perf_comm_event {
6162 struct task_struct *task;
6167 struct perf_event_header header;
6174 static int perf_event_comm_match(struct perf_event *event)
6176 return event->attr.comm;
6179 static void perf_event_comm_output(struct perf_event *event,
6182 struct perf_comm_event *comm_event = data;
6183 struct perf_output_handle handle;
6184 struct perf_sample_data sample;
6185 int size = comm_event->event_id.header.size;
6188 if (!perf_event_comm_match(event))
6191 perf_event_header__init_id(&comm_event->event_id.header, &sample, event);
6192 ret = perf_output_begin(&handle, event,
6193 comm_event->event_id.header.size);
6198 comm_event->event_id.pid = perf_event_pid(event, comm_event->task);
6199 comm_event->event_id.tid = perf_event_tid(event, comm_event->task);
6201 perf_output_put(&handle, comm_event->event_id);
6202 __output_copy(&handle, comm_event->comm,
6203 comm_event->comm_size);
6205 perf_event__output_id_sample(event, &handle, &sample);
6207 perf_output_end(&handle);
6209 comm_event->event_id.header.size = size;
6212 static void perf_event_comm_event(struct perf_comm_event *comm_event)
6214 char comm[TASK_COMM_LEN];
6217 memset(comm, 0, sizeof(comm));
6218 strlcpy(comm, comm_event->task->comm, sizeof(comm));
6219 size = ALIGN(strlen(comm)+1, sizeof(u64));
6221 comm_event->comm = comm;
6222 comm_event->comm_size = size;
6224 comm_event->event_id.header.size = sizeof(comm_event->event_id) + size;
6226 perf_event_aux(perf_event_comm_output,
6231 void perf_event_comm(struct task_struct *task, bool exec)
6233 struct perf_comm_event comm_event;
6235 if (!atomic_read(&nr_comm_events))
6238 comm_event = (struct perf_comm_event){
6244 .type = PERF_RECORD_COMM,
6245 .misc = exec ? PERF_RECORD_MISC_COMM_EXEC : 0,
6253 perf_event_comm_event(&comm_event);
6260 struct perf_mmap_event {
6261 struct vm_area_struct *vma;
6263 const char *file_name;
6271 struct perf_event_header header;
6281 static int perf_event_mmap_match(struct perf_event *event,
6284 struct perf_mmap_event *mmap_event = data;
6285 struct vm_area_struct *vma = mmap_event->vma;
6286 int executable = vma->vm_flags & VM_EXEC;
6288 return (!executable && event->attr.mmap_data) ||
6289 (executable && (event->attr.mmap || event->attr.mmap2));
6292 static void perf_event_mmap_output(struct perf_event *event,
6295 struct perf_mmap_event *mmap_event = data;
6296 struct perf_output_handle handle;
6297 struct perf_sample_data sample;
6298 int size = mmap_event->event_id.header.size;
6301 if (!perf_event_mmap_match(event, data))
6304 if (event->attr.mmap2) {
6305 mmap_event->event_id.header.type = PERF_RECORD_MMAP2;
6306 mmap_event->event_id.header.size += sizeof(mmap_event->maj);
6307 mmap_event->event_id.header.size += sizeof(mmap_event->min);
6308 mmap_event->event_id.header.size += sizeof(mmap_event->ino);
6309 mmap_event->event_id.header.size += sizeof(mmap_event->ino_generation);
6310 mmap_event->event_id.header.size += sizeof(mmap_event->prot);
6311 mmap_event->event_id.header.size += sizeof(mmap_event->flags);
6314 perf_event_header__init_id(&mmap_event->event_id.header, &sample, event);
6315 ret = perf_output_begin(&handle, event,
6316 mmap_event->event_id.header.size);
6320 mmap_event->event_id.pid = perf_event_pid(event, current);
6321 mmap_event->event_id.tid = perf_event_tid(event, current);
6323 perf_output_put(&handle, mmap_event->event_id);
6325 if (event->attr.mmap2) {
6326 perf_output_put(&handle, mmap_event->maj);
6327 perf_output_put(&handle, mmap_event->min);
6328 perf_output_put(&handle, mmap_event->ino);
6329 perf_output_put(&handle, mmap_event->ino_generation);
6330 perf_output_put(&handle, mmap_event->prot);
6331 perf_output_put(&handle, mmap_event->flags);
6334 __output_copy(&handle, mmap_event->file_name,
6335 mmap_event->file_size);
6337 perf_event__output_id_sample(event, &handle, &sample);
6339 perf_output_end(&handle);
6341 mmap_event->event_id.header.size = size;
6344 static void perf_event_mmap_event(struct perf_mmap_event *mmap_event)
6346 struct vm_area_struct *vma = mmap_event->vma;
6347 struct file *file = vma->vm_file;
6348 int maj = 0, min = 0;
6349 u64 ino = 0, gen = 0;
6350 u32 prot = 0, flags = 0;
6357 struct inode *inode;
6360 buf = kmalloc(PATH_MAX, GFP_KERNEL);
6366 * d_path() works from the end of the rb backwards, so we
6367 * need to add enough zero bytes after the string to handle
6368 * the 64bit alignment we do later.
6370 name = file_path(file, buf, PATH_MAX - sizeof(u64));
6375 inode = file_inode(vma->vm_file);
6376 dev = inode->i_sb->s_dev;
6378 gen = inode->i_generation;
6382 if (vma->vm_flags & VM_READ)
6384 if (vma->vm_flags & VM_WRITE)
6386 if (vma->vm_flags & VM_EXEC)
6389 if (vma->vm_flags & VM_MAYSHARE)
6392 flags = MAP_PRIVATE;
6394 if (vma->vm_flags & VM_DENYWRITE)
6395 flags |= MAP_DENYWRITE;
6396 if (vma->vm_flags & VM_MAYEXEC)
6397 flags |= MAP_EXECUTABLE;
6398 if (vma->vm_flags & VM_LOCKED)
6399 flags |= MAP_LOCKED;
6400 if (vma->vm_flags & VM_HUGETLB)
6401 flags |= MAP_HUGETLB;
6405 if (vma->vm_ops && vma->vm_ops->name) {
6406 name = (char *) vma->vm_ops->name(vma);
6411 name = (char *)arch_vma_name(vma);
6415 if (vma->vm_start <= vma->vm_mm->start_brk &&
6416 vma->vm_end >= vma->vm_mm->brk) {
6420 if (vma->vm_start <= vma->vm_mm->start_stack &&
6421 vma->vm_end >= vma->vm_mm->start_stack) {
6431 strlcpy(tmp, name, sizeof(tmp));
6435 * Since our buffer works in 8 byte units we need to align our string
6436 * size to a multiple of 8. However, we must guarantee the tail end is
6437 * zero'd out to avoid leaking random bits to userspace.
6439 size = strlen(name)+1;
6440 while (!IS_ALIGNED(size, sizeof(u64)))
6441 name[size++] = '\0';
6443 mmap_event->file_name = name;
6444 mmap_event->file_size = size;
6445 mmap_event->maj = maj;
6446 mmap_event->min = min;
6447 mmap_event->ino = ino;
6448 mmap_event->ino_generation = gen;
6449 mmap_event->prot = prot;
6450 mmap_event->flags = flags;
6452 if (!(vma->vm_flags & VM_EXEC))
6453 mmap_event->event_id.header.misc |= PERF_RECORD_MISC_MMAP_DATA;
6455 mmap_event->event_id.header.size = sizeof(mmap_event->event_id) + size;
6457 perf_event_aux(perf_event_mmap_output,
6465 * Whether this @filter depends on a dynamic object which is not loaded
6466 * yet or its load addresses are not known.
6468 static bool perf_addr_filter_needs_mmap(struct perf_addr_filter *filter)
6470 return filter->filter && filter->inode;
6474 * Check whether inode and address range match filter criteria.
6476 static bool perf_addr_filter_match(struct perf_addr_filter *filter,
6477 struct file *file, unsigned long offset,
6480 if (filter->inode != file->f_inode)
6483 if (filter->offset > offset + size)
6486 if (filter->offset + filter->size < offset)
6492 static void __perf_addr_filters_adjust(struct perf_event *event, void *data)
6494 struct perf_addr_filters_head *ifh = perf_event_addr_filters(event);
6495 struct vm_area_struct *vma = data;
6496 unsigned long off = vma->vm_pgoff << PAGE_SHIFT, flags;
6497 struct file *file = vma->vm_file;
6498 struct perf_addr_filter *filter;
6499 unsigned int restart = 0, count = 0;
6501 if (!has_addr_filter(event))
6507 raw_spin_lock_irqsave(&ifh->lock, flags);
6508 list_for_each_entry(filter, &ifh->list, entry) {
6509 if (perf_addr_filter_match(filter, file, off,
6510 vma->vm_end - vma->vm_start)) {
6511 event->addr_filters_offs[count] = vma->vm_start;
6519 event->addr_filters_gen++;
6520 raw_spin_unlock_irqrestore(&ifh->lock, flags);
6523 perf_event_restart(event);
6527 * Adjust all task's events' filters to the new vma
6529 static void perf_addr_filters_adjust(struct vm_area_struct *vma)
6531 struct perf_event_context *ctx;
6535 for_each_task_context_nr(ctxn) {
6536 ctx = rcu_dereference(current->perf_event_ctxp[ctxn]);
6540 perf_event_aux_ctx(ctx, __perf_addr_filters_adjust, vma, true);
6545 void perf_event_mmap(struct vm_area_struct *vma)
6547 struct perf_mmap_event mmap_event;
6549 if (!atomic_read(&nr_mmap_events))
6552 mmap_event = (struct perf_mmap_event){
6558 .type = PERF_RECORD_MMAP,
6559 .misc = PERF_RECORD_MISC_USER,
6564 .start = vma->vm_start,
6565 .len = vma->vm_end - vma->vm_start,
6566 .pgoff = (u64)vma->vm_pgoff << PAGE_SHIFT,
6568 /* .maj (attr_mmap2 only) */
6569 /* .min (attr_mmap2 only) */
6570 /* .ino (attr_mmap2 only) */
6571 /* .ino_generation (attr_mmap2 only) */
6572 /* .prot (attr_mmap2 only) */
6573 /* .flags (attr_mmap2 only) */
6576 perf_addr_filters_adjust(vma);
6577 perf_event_mmap_event(&mmap_event);
6580 void perf_event_aux_event(struct perf_event *event, unsigned long head,
6581 unsigned long size, u64 flags)
6583 struct perf_output_handle handle;
6584 struct perf_sample_data sample;
6585 struct perf_aux_event {
6586 struct perf_event_header header;
6592 .type = PERF_RECORD_AUX,
6594 .size = sizeof(rec),
6602 perf_event_header__init_id(&rec.header, &sample, event);
6603 ret = perf_output_begin(&handle, event, rec.header.size);
6608 perf_output_put(&handle, rec);
6609 perf_event__output_id_sample(event, &handle, &sample);
6611 perf_output_end(&handle);
6615 * Lost/dropped samples logging
6617 void perf_log_lost_samples(struct perf_event *event, u64 lost)
6619 struct perf_output_handle handle;
6620 struct perf_sample_data sample;
6624 struct perf_event_header header;
6626 } lost_samples_event = {
6628 .type = PERF_RECORD_LOST_SAMPLES,
6630 .size = sizeof(lost_samples_event),
6635 perf_event_header__init_id(&lost_samples_event.header, &sample, event);
6637 ret = perf_output_begin(&handle, event,
6638 lost_samples_event.header.size);
6642 perf_output_put(&handle, lost_samples_event);
6643 perf_event__output_id_sample(event, &handle, &sample);
6644 perf_output_end(&handle);
6648 * context_switch tracking
6651 struct perf_switch_event {
6652 struct task_struct *task;
6653 struct task_struct *next_prev;
6656 struct perf_event_header header;
6662 static int perf_event_switch_match(struct perf_event *event)
6664 return event->attr.context_switch;
6667 static void perf_event_switch_output(struct perf_event *event, void *data)
6669 struct perf_switch_event *se = data;
6670 struct perf_output_handle handle;
6671 struct perf_sample_data sample;
6674 if (!perf_event_switch_match(event))
6677 /* Only CPU-wide events are allowed to see next/prev pid/tid */
6678 if (event->ctx->task) {
6679 se->event_id.header.type = PERF_RECORD_SWITCH;
6680 se->event_id.header.size = sizeof(se->event_id.header);
6682 se->event_id.header.type = PERF_RECORD_SWITCH_CPU_WIDE;
6683 se->event_id.header.size = sizeof(se->event_id);
6684 se->event_id.next_prev_pid =
6685 perf_event_pid(event, se->next_prev);
6686 se->event_id.next_prev_tid =
6687 perf_event_tid(event, se->next_prev);
6690 perf_event_header__init_id(&se->event_id.header, &sample, event);
6692 ret = perf_output_begin(&handle, event, se->event_id.header.size);
6696 if (event->ctx->task)
6697 perf_output_put(&handle, se->event_id.header);
6699 perf_output_put(&handle, se->event_id);
6701 perf_event__output_id_sample(event, &handle, &sample);
6703 perf_output_end(&handle);
6706 static void perf_event_switch(struct task_struct *task,
6707 struct task_struct *next_prev, bool sched_in)
6709 struct perf_switch_event switch_event;
6711 /* N.B. caller checks nr_switch_events != 0 */
6713 switch_event = (struct perf_switch_event){
6715 .next_prev = next_prev,
6719 .misc = sched_in ? 0 : PERF_RECORD_MISC_SWITCH_OUT,
6722 /* .next_prev_pid */
6723 /* .next_prev_tid */
6727 perf_event_aux(perf_event_switch_output,
6733 * IRQ throttle logging
6736 static void perf_log_throttle(struct perf_event *event, int enable)
6738 struct perf_output_handle handle;
6739 struct perf_sample_data sample;
6743 struct perf_event_header header;
6747 } throttle_event = {
6749 .type = PERF_RECORD_THROTTLE,
6751 .size = sizeof(throttle_event),
6753 .time = perf_event_clock(event),
6754 .id = primary_event_id(event),
6755 .stream_id = event->id,
6759 throttle_event.header.type = PERF_RECORD_UNTHROTTLE;
6761 perf_event_header__init_id(&throttle_event.header, &sample, event);
6763 ret = perf_output_begin(&handle, event,
6764 throttle_event.header.size);
6768 perf_output_put(&handle, throttle_event);
6769 perf_event__output_id_sample(event, &handle, &sample);
6770 perf_output_end(&handle);
6773 static void perf_log_itrace_start(struct perf_event *event)
6775 struct perf_output_handle handle;
6776 struct perf_sample_data sample;
6777 struct perf_aux_event {
6778 struct perf_event_header header;
6785 event = event->parent;
6787 if (!(event->pmu->capabilities & PERF_PMU_CAP_ITRACE) ||
6788 event->hw.itrace_started)
6791 rec.header.type = PERF_RECORD_ITRACE_START;
6792 rec.header.misc = 0;
6793 rec.header.size = sizeof(rec);
6794 rec.pid = perf_event_pid(event, current);
6795 rec.tid = perf_event_tid(event, current);
6797 perf_event_header__init_id(&rec.header, &sample, event);
6798 ret = perf_output_begin(&handle, event, rec.header.size);
6803 perf_output_put(&handle, rec);
6804 perf_event__output_id_sample(event, &handle, &sample);
6806 perf_output_end(&handle);
6810 * Generic event overflow handling, sampling.
6813 static int __perf_event_overflow(struct perf_event *event,
6814 int throttle, struct perf_sample_data *data,
6815 struct pt_regs *regs)
6817 int events = atomic_read(&event->event_limit);
6818 struct hw_perf_event *hwc = &event->hw;
6823 * Non-sampling counters might still use the PMI to fold short
6824 * hardware counters, ignore those.
6826 if (unlikely(!is_sampling_event(event)))
6829 seq = __this_cpu_read(perf_throttled_seq);
6830 if (seq != hwc->interrupts_seq) {
6831 hwc->interrupts_seq = seq;
6832 hwc->interrupts = 1;
6835 if (unlikely(throttle
6836 && hwc->interrupts >= max_samples_per_tick)) {
6837 __this_cpu_inc(perf_throttled_count);
6838 tick_dep_set_cpu(smp_processor_id(), TICK_DEP_BIT_PERF_EVENTS);
6839 hwc->interrupts = MAX_INTERRUPTS;
6840 perf_log_throttle(event, 0);
6845 if (event->attr.freq) {
6846 u64 now = perf_clock();
6847 s64 delta = now - hwc->freq_time_stamp;
6849 hwc->freq_time_stamp = now;
6851 if (delta > 0 && delta < 2*TICK_NSEC)
6852 perf_adjust_period(event, delta, hwc->last_period, true);
6856 * XXX event_limit might not quite work as expected on inherited
6860 event->pending_kill = POLL_IN;
6861 if (events && atomic_dec_and_test(&event->event_limit)) {
6863 event->pending_kill = POLL_HUP;
6864 event->pending_disable = 1;
6865 irq_work_queue(&event->pending);
6868 event->overflow_handler(event, data, regs);
6870 if (*perf_event_fasync(event) && event->pending_kill) {
6871 event->pending_wakeup = 1;
6872 irq_work_queue(&event->pending);
6878 int perf_event_overflow(struct perf_event *event,
6879 struct perf_sample_data *data,
6880 struct pt_regs *regs)
6882 return __perf_event_overflow(event, 1, data, regs);
6886 * Generic software event infrastructure
6889 struct swevent_htable {
6890 struct swevent_hlist *swevent_hlist;
6891 struct mutex hlist_mutex;
6894 /* Recursion avoidance in each contexts */
6895 int recursion[PERF_NR_CONTEXTS];
6898 static DEFINE_PER_CPU(struct swevent_htable, swevent_htable);
6901 * We directly increment event->count and keep a second value in
6902 * event->hw.period_left to count intervals. This period event
6903 * is kept in the range [-sample_period, 0] so that we can use the
6907 u64 perf_swevent_set_period(struct perf_event *event)
6909 struct hw_perf_event *hwc = &event->hw;
6910 u64 period = hwc->last_period;
6914 hwc->last_period = hwc->sample_period;
6917 old = val = local64_read(&hwc->period_left);
6921 nr = div64_u64(period + val, period);
6922 offset = nr * period;
6924 if (local64_cmpxchg(&hwc->period_left, old, val) != old)
6930 static void perf_swevent_overflow(struct perf_event *event, u64 overflow,
6931 struct perf_sample_data *data,
6932 struct pt_regs *regs)
6934 struct hw_perf_event *hwc = &event->hw;
6938 overflow = perf_swevent_set_period(event);
6940 if (hwc->interrupts == MAX_INTERRUPTS)
6943 for (; overflow; overflow--) {
6944 if (__perf_event_overflow(event, throttle,
6947 * We inhibit the overflow from happening when
6948 * hwc->interrupts == MAX_INTERRUPTS.
6956 static void perf_swevent_event(struct perf_event *event, u64 nr,
6957 struct perf_sample_data *data,
6958 struct pt_regs *regs)
6960 struct hw_perf_event *hwc = &event->hw;
6962 local64_add(nr, &event->count);
6967 if (!is_sampling_event(event))
6970 if ((event->attr.sample_type & PERF_SAMPLE_PERIOD) && !event->attr.freq) {
6972 return perf_swevent_overflow(event, 1, data, regs);
6974 data->period = event->hw.last_period;
6976 if (nr == 1 && hwc->sample_period == 1 && !event->attr.freq)
6977 return perf_swevent_overflow(event, 1, data, regs);
6979 if (local64_add_negative(nr, &hwc->period_left))
6982 perf_swevent_overflow(event, 0, data, regs);
6985 static int perf_exclude_event(struct perf_event *event,
6986 struct pt_regs *regs)
6988 if (event->hw.state & PERF_HES_STOPPED)
6992 if (event->attr.exclude_user && user_mode(regs))
6995 if (event->attr.exclude_kernel && !user_mode(regs))
7002 static int perf_swevent_match(struct perf_event *event,
7003 enum perf_type_id type,
7005 struct perf_sample_data *data,
7006 struct pt_regs *regs)
7008 if (event->attr.type != type)
7011 if (event->attr.config != event_id)
7014 if (perf_exclude_event(event, regs))
7020 static inline u64 swevent_hash(u64 type, u32 event_id)
7022 u64 val = event_id | (type << 32);
7024 return hash_64(val, SWEVENT_HLIST_BITS);
7027 static inline struct hlist_head *
7028 __find_swevent_head(struct swevent_hlist *hlist, u64 type, u32 event_id)
7030 u64 hash = swevent_hash(type, event_id);
7032 return &hlist->heads[hash];
7035 /* For the read side: events when they trigger */
7036 static inline struct hlist_head *
7037 find_swevent_head_rcu(struct swevent_htable *swhash, u64 type, u32 event_id)
7039 struct swevent_hlist *hlist;
7041 hlist = rcu_dereference(swhash->swevent_hlist);
7045 return __find_swevent_head(hlist, type, event_id);
7048 /* For the event head insertion and removal in the hlist */
7049 static inline struct hlist_head *
7050 find_swevent_head(struct swevent_htable *swhash, struct perf_event *event)
7052 struct swevent_hlist *hlist;
7053 u32 event_id = event->attr.config;
7054 u64 type = event->attr.type;
7057 * Event scheduling is always serialized against hlist allocation
7058 * and release. Which makes the protected version suitable here.
7059 * The context lock guarantees that.
7061 hlist = rcu_dereference_protected(swhash->swevent_hlist,
7062 lockdep_is_held(&event->ctx->lock));
7066 return __find_swevent_head(hlist, type, event_id);
7069 static void do_perf_sw_event(enum perf_type_id type, u32 event_id,
7071 struct perf_sample_data *data,
7072 struct pt_regs *regs)
7074 struct swevent_htable *swhash = this_cpu_ptr(&swevent_htable);
7075 struct perf_event *event;
7076 struct hlist_head *head;
7079 head = find_swevent_head_rcu(swhash, type, event_id);
7083 hlist_for_each_entry_rcu(event, head, hlist_entry) {
7084 if (perf_swevent_match(event, type, event_id, data, regs))
7085 perf_swevent_event(event, nr, data, regs);
7091 DEFINE_PER_CPU(struct pt_regs, __perf_regs[4]);
7093 int perf_swevent_get_recursion_context(void)
7095 struct swevent_htable *swhash = this_cpu_ptr(&swevent_htable);
7097 return get_recursion_context(swhash->recursion);
7099 EXPORT_SYMBOL_GPL(perf_swevent_get_recursion_context);
7101 void perf_swevent_put_recursion_context(int rctx)
7103 struct swevent_htable *swhash = this_cpu_ptr(&swevent_htable);
7105 put_recursion_context(swhash->recursion, rctx);
7108 void ___perf_sw_event(u32 event_id, u64 nr, struct pt_regs *regs, u64 addr)
7110 struct perf_sample_data data;
7112 if (WARN_ON_ONCE(!regs))
7115 perf_sample_data_init(&data, addr, 0);
7116 do_perf_sw_event(PERF_TYPE_SOFTWARE, event_id, nr, &data, regs);
7119 void __perf_sw_event(u32 event_id, u64 nr, struct pt_regs *regs, u64 addr)
7123 preempt_disable_notrace();
7124 rctx = perf_swevent_get_recursion_context();
7125 if (unlikely(rctx < 0))
7128 ___perf_sw_event(event_id, nr, regs, addr);
7130 perf_swevent_put_recursion_context(rctx);
7132 preempt_enable_notrace();
7135 static void perf_swevent_read(struct perf_event *event)
7139 static int perf_swevent_add(struct perf_event *event, int flags)
7141 struct swevent_htable *swhash = this_cpu_ptr(&swevent_htable);
7142 struct hw_perf_event *hwc = &event->hw;
7143 struct hlist_head *head;
7145 if (is_sampling_event(event)) {
7146 hwc->last_period = hwc->sample_period;
7147 perf_swevent_set_period(event);
7150 hwc->state = !(flags & PERF_EF_START);
7152 head = find_swevent_head(swhash, event);
7153 if (WARN_ON_ONCE(!head))
7156 hlist_add_head_rcu(&event->hlist_entry, head);
7157 perf_event_update_userpage(event);
7162 static void perf_swevent_del(struct perf_event *event, int flags)
7164 hlist_del_rcu(&event->hlist_entry);
7167 static void perf_swevent_start(struct perf_event *event, int flags)
7169 event->hw.state = 0;
7172 static void perf_swevent_stop(struct perf_event *event, int flags)
7174 event->hw.state = PERF_HES_STOPPED;
7177 /* Deref the hlist from the update side */
7178 static inline struct swevent_hlist *
7179 swevent_hlist_deref(struct swevent_htable *swhash)
7181 return rcu_dereference_protected(swhash->swevent_hlist,
7182 lockdep_is_held(&swhash->hlist_mutex));
7185 static void swevent_hlist_release(struct swevent_htable *swhash)
7187 struct swevent_hlist *hlist = swevent_hlist_deref(swhash);
7192 RCU_INIT_POINTER(swhash->swevent_hlist, NULL);
7193 kfree_rcu(hlist, rcu_head);
7196 static void swevent_hlist_put_cpu(int cpu)
7198 struct swevent_htable *swhash = &per_cpu(swevent_htable, cpu);
7200 mutex_lock(&swhash->hlist_mutex);
7202 if (!--swhash->hlist_refcount)
7203 swevent_hlist_release(swhash);
7205 mutex_unlock(&swhash->hlist_mutex);
7208 static void swevent_hlist_put(void)
7212 for_each_possible_cpu(cpu)
7213 swevent_hlist_put_cpu(cpu);
7216 static int swevent_hlist_get_cpu(int cpu)
7218 struct swevent_htable *swhash = &per_cpu(swevent_htable, cpu);
7221 mutex_lock(&swhash->hlist_mutex);
7222 if (!swevent_hlist_deref(swhash) && cpu_online(cpu)) {
7223 struct swevent_hlist *hlist;
7225 hlist = kzalloc(sizeof(*hlist), GFP_KERNEL);
7230 rcu_assign_pointer(swhash->swevent_hlist, hlist);
7232 swhash->hlist_refcount++;
7234 mutex_unlock(&swhash->hlist_mutex);
7239 static int swevent_hlist_get(void)
7241 int err, cpu, failed_cpu;
7244 for_each_possible_cpu(cpu) {
7245 err = swevent_hlist_get_cpu(cpu);
7255 for_each_possible_cpu(cpu) {
7256 if (cpu == failed_cpu)
7258 swevent_hlist_put_cpu(cpu);
7265 struct static_key perf_swevent_enabled[PERF_COUNT_SW_MAX];
7267 static void sw_perf_event_destroy(struct perf_event *event)
7269 u64 event_id = event->attr.config;
7271 WARN_ON(event->parent);
7273 static_key_slow_dec(&perf_swevent_enabled[event_id]);
7274 swevent_hlist_put();
7277 static int perf_swevent_init(struct perf_event *event)
7279 u64 event_id = event->attr.config;
7281 if (event->attr.type != PERF_TYPE_SOFTWARE)
7285 * no branch sampling for software events
7287 if (has_branch_stack(event))
7291 case PERF_COUNT_SW_CPU_CLOCK:
7292 case PERF_COUNT_SW_TASK_CLOCK:
7299 if (event_id >= PERF_COUNT_SW_MAX)
7302 if (!event->parent) {
7305 err = swevent_hlist_get();
7309 static_key_slow_inc(&perf_swevent_enabled[event_id]);
7310 event->destroy = sw_perf_event_destroy;
7316 static struct pmu perf_swevent = {
7317 .task_ctx_nr = perf_sw_context,
7319 .capabilities = PERF_PMU_CAP_NO_NMI,
7321 .event_init = perf_swevent_init,
7322 .add = perf_swevent_add,
7323 .del = perf_swevent_del,
7324 .start = perf_swevent_start,
7325 .stop = perf_swevent_stop,
7326 .read = perf_swevent_read,
7329 #ifdef CONFIG_EVENT_TRACING
7331 static int perf_tp_filter_match(struct perf_event *event,
7332 struct perf_sample_data *data)
7334 void *record = data->raw->data;
7336 /* only top level events have filters set */
7338 event = event->parent;
7340 if (likely(!event->filter) || filter_match_preds(event->filter, record))
7345 static int perf_tp_event_match(struct perf_event *event,
7346 struct perf_sample_data *data,
7347 struct pt_regs *regs)
7349 if (event->hw.state & PERF_HES_STOPPED)
7352 * All tracepoints are from kernel-space.
7354 if (event->attr.exclude_kernel)
7357 if (!perf_tp_filter_match(event, data))
7363 void perf_trace_run_bpf_submit(void *raw_data, int size, int rctx,
7364 struct trace_event_call *call, u64 count,
7365 struct pt_regs *regs, struct hlist_head *head,
7366 struct task_struct *task)
7368 struct bpf_prog *prog = call->prog;
7371 *(struct pt_regs **)raw_data = regs;
7372 if (!trace_call_bpf(prog, raw_data) || hlist_empty(head)) {
7373 perf_swevent_put_recursion_context(rctx);
7377 perf_tp_event(call->event.type, count, raw_data, size, regs, head,
7380 EXPORT_SYMBOL_GPL(perf_trace_run_bpf_submit);
7382 void perf_tp_event(u16 event_type, u64 count, void *record, int entry_size,
7383 struct pt_regs *regs, struct hlist_head *head, int rctx,
7384 struct task_struct *task)
7386 struct perf_sample_data data;
7387 struct perf_event *event;
7389 struct perf_raw_record raw = {
7394 perf_sample_data_init(&data, 0, 0);
7397 perf_trace_buf_update(record, event_type);
7399 hlist_for_each_entry_rcu(event, head, hlist_entry) {
7400 if (perf_tp_event_match(event, &data, regs))
7401 perf_swevent_event(event, count, &data, regs);
7405 * If we got specified a target task, also iterate its context and
7406 * deliver this event there too.
7408 if (task && task != current) {
7409 struct perf_event_context *ctx;
7410 struct trace_entry *entry = record;
7413 ctx = rcu_dereference(task->perf_event_ctxp[perf_sw_context]);
7417 list_for_each_entry_rcu(event, &ctx->event_list, event_entry) {
7418 if (event->attr.type != PERF_TYPE_TRACEPOINT)
7420 if (event->attr.config != entry->type)
7422 if (perf_tp_event_match(event, &data, regs))
7423 perf_swevent_event(event, count, &data, regs);
7429 perf_swevent_put_recursion_context(rctx);
7431 EXPORT_SYMBOL_GPL(perf_tp_event);
7433 static void tp_perf_event_destroy(struct perf_event *event)
7435 perf_trace_destroy(event);
7438 static int perf_tp_event_init(struct perf_event *event)
7442 if (event->attr.type != PERF_TYPE_TRACEPOINT)
7446 * no branch sampling for tracepoint events
7448 if (has_branch_stack(event))
7451 err = perf_trace_init(event);
7455 event->destroy = tp_perf_event_destroy;
7460 static struct pmu perf_tracepoint = {
7461 .task_ctx_nr = perf_sw_context,
7463 .event_init = perf_tp_event_init,
7464 .add = perf_trace_add,
7465 .del = perf_trace_del,
7466 .start = perf_swevent_start,
7467 .stop = perf_swevent_stop,
7468 .read = perf_swevent_read,
7471 static inline void perf_tp_register(void)
7473 perf_pmu_register(&perf_tracepoint, "tracepoint", PERF_TYPE_TRACEPOINT);
7476 static void perf_event_free_filter(struct perf_event *event)
7478 ftrace_profile_free_filter(event);
7481 static int perf_event_set_bpf_prog(struct perf_event *event, u32 prog_fd)
7483 bool is_kprobe, is_tracepoint;
7484 struct bpf_prog *prog;
7486 if (event->attr.type != PERF_TYPE_TRACEPOINT)
7489 if (event->tp_event->prog)
7492 is_kprobe = event->tp_event->flags & TRACE_EVENT_FL_UKPROBE;
7493 is_tracepoint = event->tp_event->flags & TRACE_EVENT_FL_TRACEPOINT;
7494 if (!is_kprobe && !is_tracepoint)
7495 /* bpf programs can only be attached to u/kprobe or tracepoint */
7498 prog = bpf_prog_get(prog_fd);
7500 return PTR_ERR(prog);
7502 if ((is_kprobe && prog->type != BPF_PROG_TYPE_KPROBE) ||
7503 (is_tracepoint && prog->type != BPF_PROG_TYPE_TRACEPOINT)) {
7504 /* valid fd, but invalid bpf program type */
7509 if (is_tracepoint) {
7510 int off = trace_event_get_offsets(event->tp_event);
7512 if (prog->aux->max_ctx_offset > off) {
7517 event->tp_event->prog = prog;
7522 static void perf_event_free_bpf_prog(struct perf_event *event)
7524 struct bpf_prog *prog;
7526 if (!event->tp_event)
7529 prog = event->tp_event->prog;
7531 event->tp_event->prog = NULL;
7532 bpf_prog_put_rcu(prog);
7538 static inline void perf_tp_register(void)
7542 static void perf_event_free_filter(struct perf_event *event)
7546 static int perf_event_set_bpf_prog(struct perf_event *event, u32 prog_fd)
7551 static void perf_event_free_bpf_prog(struct perf_event *event)
7554 #endif /* CONFIG_EVENT_TRACING */
7556 #ifdef CONFIG_HAVE_HW_BREAKPOINT
7557 void perf_bp_event(struct perf_event *bp, void *data)
7559 struct perf_sample_data sample;
7560 struct pt_regs *regs = data;
7562 perf_sample_data_init(&sample, bp->attr.bp_addr, 0);
7564 if (!bp->hw.state && !perf_exclude_event(bp, regs))
7565 perf_swevent_event(bp, 1, &sample, regs);
7570 * Allocate a new address filter
7572 static struct perf_addr_filter *
7573 perf_addr_filter_new(struct perf_event *event, struct list_head *filters)
7575 int node = cpu_to_node(event->cpu == -1 ? 0 : event->cpu);
7576 struct perf_addr_filter *filter;
7578 filter = kzalloc_node(sizeof(*filter), GFP_KERNEL, node);
7582 INIT_LIST_HEAD(&filter->entry);
7583 list_add_tail(&filter->entry, filters);
7588 static void free_filters_list(struct list_head *filters)
7590 struct perf_addr_filter *filter, *iter;
7592 list_for_each_entry_safe(filter, iter, filters, entry) {
7594 iput(filter->inode);
7595 list_del(&filter->entry);
7601 * Free existing address filters and optionally install new ones
7603 static void perf_addr_filters_splice(struct perf_event *event,
7604 struct list_head *head)
7606 unsigned long flags;
7609 if (!has_addr_filter(event))
7612 /* don't bother with children, they don't have their own filters */
7616 raw_spin_lock_irqsave(&event->addr_filters.lock, flags);
7618 list_splice_init(&event->addr_filters.list, &list);
7620 list_splice(head, &event->addr_filters.list);
7622 raw_spin_unlock_irqrestore(&event->addr_filters.lock, flags);
7624 free_filters_list(&list);
7628 * Scan through mm's vmas and see if one of them matches the
7629 * @filter; if so, adjust filter's address range.
7630 * Called with mm::mmap_sem down for reading.
7632 static unsigned long perf_addr_filter_apply(struct perf_addr_filter *filter,
7633 struct mm_struct *mm)
7635 struct vm_area_struct *vma;
7637 for (vma = mm->mmap; vma; vma = vma->vm_next) {
7638 struct file *file = vma->vm_file;
7639 unsigned long off = vma->vm_pgoff << PAGE_SHIFT;
7640 unsigned long vma_size = vma->vm_end - vma->vm_start;
7645 if (!perf_addr_filter_match(filter, file, off, vma_size))
7648 return vma->vm_start;
7655 * Update event's address range filters based on the
7656 * task's existing mappings, if any.
7658 static void perf_event_addr_filters_apply(struct perf_event *event)
7660 struct perf_addr_filters_head *ifh = perf_event_addr_filters(event);
7661 struct task_struct *task = READ_ONCE(event->ctx->task);
7662 struct perf_addr_filter *filter;
7663 struct mm_struct *mm = NULL;
7664 unsigned int count = 0;
7665 unsigned long flags;
7668 * We may observe TASK_TOMBSTONE, which means that the event tear-down
7669 * will stop on the parent's child_mutex that our caller is also holding
7671 if (task == TASK_TOMBSTONE)
7674 mm = get_task_mm(event->ctx->task);
7678 down_read(&mm->mmap_sem);
7680 raw_spin_lock_irqsave(&ifh->lock, flags);
7681 list_for_each_entry(filter, &ifh->list, entry) {
7682 event->addr_filters_offs[count] = 0;
7684 if (perf_addr_filter_needs_mmap(filter))
7685 event->addr_filters_offs[count] =
7686 perf_addr_filter_apply(filter, mm);
7691 event->addr_filters_gen++;
7692 raw_spin_unlock_irqrestore(&ifh->lock, flags);
7694 up_read(&mm->mmap_sem);
7699 perf_event_restart(event);
7703 * Address range filtering: limiting the data to certain
7704 * instruction address ranges. Filters are ioctl()ed to us from
7705 * userspace as ascii strings.
7707 * Filter string format:
7710 * where ACTION is one of the
7711 * * "filter": limit the trace to this region
7712 * * "start": start tracing from this address
7713 * * "stop": stop tracing at this address/region;
7715 * * for kernel addresses: <start address>[/<size>]
7716 * * for object files: <start address>[/<size>]@</path/to/object/file>
7718 * if <size> is not specified, the range is treated as a single address.
7731 IF_STATE_ACTION = 0,
7736 static const match_table_t if_tokens = {
7737 { IF_ACT_FILTER, "filter" },
7738 { IF_ACT_START, "start" },
7739 { IF_ACT_STOP, "stop" },
7740 { IF_SRC_FILE, "%u/%u@%s" },
7741 { IF_SRC_KERNEL, "%u/%u" },
7742 { IF_SRC_FILEADDR, "%u@%s" },
7743 { IF_SRC_KERNELADDR, "%u" },
7747 * Address filter string parser
7750 perf_event_parse_addr_filter(struct perf_event *event, char *fstr,
7751 struct list_head *filters)
7753 struct perf_addr_filter *filter = NULL;
7754 char *start, *orig, *filename = NULL;
7756 substring_t args[MAX_OPT_ARGS];
7757 int state = IF_STATE_ACTION, token;
7758 unsigned int kernel = 0;
7761 orig = fstr = kstrdup(fstr, GFP_KERNEL);
7765 while ((start = strsep(&fstr, " ,\n")) != NULL) {
7771 /* filter definition begins */
7772 if (state == IF_STATE_ACTION) {
7773 filter = perf_addr_filter_new(event, filters);
7778 token = match_token(start, if_tokens, args);
7785 if (state != IF_STATE_ACTION)
7788 state = IF_STATE_SOURCE;
7791 case IF_SRC_KERNELADDR:
7795 case IF_SRC_FILEADDR:
7797 if (state != IF_STATE_SOURCE)
7800 if (token == IF_SRC_FILE || token == IF_SRC_KERNEL)
7804 ret = kstrtoul(args[0].from, 0, &filter->offset);
7808 if (filter->range) {
7810 ret = kstrtoul(args[1].from, 0, &filter->size);
7815 if (token == IF_SRC_FILE) {
7816 filename = match_strdup(&args[2]);
7823 state = IF_STATE_END;
7831 * Filter definition is fully parsed, validate and install it.
7832 * Make sure that it doesn't contradict itself or the event's
7835 if (state == IF_STATE_END) {
7836 if (kernel && event->attr.exclude_kernel)
7843 /* look up the path and grab its inode */
7844 ret = kern_path(filename, LOOKUP_FOLLOW, &path);
7846 goto fail_free_name;
7848 filter->inode = igrab(d_inode(path.dentry));
7854 if (!filter->inode ||
7855 !S_ISREG(filter->inode->i_mode))
7856 /* free_filters_list() will iput() */
7860 /* ready to consume more filters */
7861 state = IF_STATE_ACTION;
7866 if (state != IF_STATE_ACTION)
7876 free_filters_list(filters);
7883 perf_event_set_addr_filter(struct perf_event *event, char *filter_str)
7889 * Since this is called in perf_ioctl() path, we're already holding
7892 lockdep_assert_held(&event->ctx->mutex);
7894 if (WARN_ON_ONCE(event->parent))
7898 * For now, we only support filtering in per-task events; doing so
7899 * for CPU-wide events requires additional context switching trickery,
7900 * since same object code will be mapped at different virtual
7901 * addresses in different processes.
7903 if (!event->ctx->task)
7906 ret = perf_event_parse_addr_filter(event, filter_str, &filters);
7910 ret = event->pmu->addr_filters_validate(&filters);
7912 free_filters_list(&filters);
7916 /* remove existing filters, if any */
7917 perf_addr_filters_splice(event, &filters);
7919 /* install new filters */
7920 perf_event_for_each_child(event, perf_event_addr_filters_apply);
7925 static int perf_event_set_filter(struct perf_event *event, void __user *arg)
7930 if ((event->attr.type != PERF_TYPE_TRACEPOINT ||
7931 !IS_ENABLED(CONFIG_EVENT_TRACING)) &&
7932 !has_addr_filter(event))
7935 filter_str = strndup_user(arg, PAGE_SIZE);
7936 if (IS_ERR(filter_str))
7937 return PTR_ERR(filter_str);
7939 if (IS_ENABLED(CONFIG_EVENT_TRACING) &&
7940 event->attr.type == PERF_TYPE_TRACEPOINT)
7941 ret = ftrace_profile_set_filter(event, event->attr.config,
7943 else if (has_addr_filter(event))
7944 ret = perf_event_set_addr_filter(event, filter_str);
7951 * hrtimer based swevent callback
7954 static enum hrtimer_restart perf_swevent_hrtimer(struct hrtimer *hrtimer)
7956 enum hrtimer_restart ret = HRTIMER_RESTART;
7957 struct perf_sample_data data;
7958 struct pt_regs *regs;
7959 struct perf_event *event;
7962 event = container_of(hrtimer, struct perf_event, hw.hrtimer);
7964 if (event->state != PERF_EVENT_STATE_ACTIVE)
7965 return HRTIMER_NORESTART;
7967 event->pmu->read(event);
7969 perf_sample_data_init(&data, 0, event->hw.last_period);
7970 regs = get_irq_regs();
7972 if (regs && !perf_exclude_event(event, regs)) {
7973 if (!(event->attr.exclude_idle && is_idle_task(current)))
7974 if (__perf_event_overflow(event, 1, &data, regs))
7975 ret = HRTIMER_NORESTART;
7978 period = max_t(u64, 10000, event->hw.sample_period);
7979 hrtimer_forward_now(hrtimer, ns_to_ktime(period));
7984 static void perf_swevent_start_hrtimer(struct perf_event *event)
7986 struct hw_perf_event *hwc = &event->hw;
7989 if (!is_sampling_event(event))
7992 period = local64_read(&hwc->period_left);
7997 local64_set(&hwc->period_left, 0);
7999 period = max_t(u64, 10000, hwc->sample_period);
8001 hrtimer_start(&hwc->hrtimer, ns_to_ktime(period),
8002 HRTIMER_MODE_REL_PINNED);
8005 static void perf_swevent_cancel_hrtimer(struct perf_event *event)
8007 struct hw_perf_event *hwc = &event->hw;
8009 if (is_sampling_event(event)) {
8010 ktime_t remaining = hrtimer_get_remaining(&hwc->hrtimer);
8011 local64_set(&hwc->period_left, ktime_to_ns(remaining));
8013 hrtimer_cancel(&hwc->hrtimer);
8017 static void perf_swevent_init_hrtimer(struct perf_event *event)
8019 struct hw_perf_event *hwc = &event->hw;
8021 if (!is_sampling_event(event))
8024 hrtimer_init(&hwc->hrtimer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
8025 hwc->hrtimer.function = perf_swevent_hrtimer;
8028 * Since hrtimers have a fixed rate, we can do a static freq->period
8029 * mapping and avoid the whole period adjust feedback stuff.
8031 if (event->attr.freq) {
8032 long freq = event->attr.sample_freq;
8034 event->attr.sample_period = NSEC_PER_SEC / freq;
8035 hwc->sample_period = event->attr.sample_period;
8036 local64_set(&hwc->period_left, hwc->sample_period);
8037 hwc->last_period = hwc->sample_period;
8038 event->attr.freq = 0;
8043 * Software event: cpu wall time clock
8046 static void cpu_clock_event_update(struct perf_event *event)
8051 now = local_clock();
8052 prev = local64_xchg(&event->hw.prev_count, now);
8053 local64_add(now - prev, &event->count);
8056 static void cpu_clock_event_start(struct perf_event *event, int flags)
8058 local64_set(&event->hw.prev_count, local_clock());
8059 perf_swevent_start_hrtimer(event);
8062 static void cpu_clock_event_stop(struct perf_event *event, int flags)
8064 perf_swevent_cancel_hrtimer(event);
8065 cpu_clock_event_update(event);
8068 static int cpu_clock_event_add(struct perf_event *event, int flags)
8070 if (flags & PERF_EF_START)
8071 cpu_clock_event_start(event, flags);
8072 perf_event_update_userpage(event);
8077 static void cpu_clock_event_del(struct perf_event *event, int flags)
8079 cpu_clock_event_stop(event, flags);
8082 static void cpu_clock_event_read(struct perf_event *event)
8084 cpu_clock_event_update(event);
8087 static int cpu_clock_event_init(struct perf_event *event)
8089 if (event->attr.type != PERF_TYPE_SOFTWARE)
8092 if (event->attr.config != PERF_COUNT_SW_CPU_CLOCK)
8096 * no branch sampling for software events
8098 if (has_branch_stack(event))
8101 perf_swevent_init_hrtimer(event);
8106 static struct pmu perf_cpu_clock = {
8107 .task_ctx_nr = perf_sw_context,
8109 .capabilities = PERF_PMU_CAP_NO_NMI,
8111 .event_init = cpu_clock_event_init,
8112 .add = cpu_clock_event_add,
8113 .del = cpu_clock_event_del,
8114 .start = cpu_clock_event_start,
8115 .stop = cpu_clock_event_stop,
8116 .read = cpu_clock_event_read,
8120 * Software event: task time clock
8123 static void task_clock_event_update(struct perf_event *event, u64 now)
8128 prev = local64_xchg(&event->hw.prev_count, now);
8130 local64_add(delta, &event->count);
8133 static void task_clock_event_start(struct perf_event *event, int flags)
8135 local64_set(&event->hw.prev_count, event->ctx->time);
8136 perf_swevent_start_hrtimer(event);
8139 static void task_clock_event_stop(struct perf_event *event, int flags)
8141 perf_swevent_cancel_hrtimer(event);
8142 task_clock_event_update(event, event->ctx->time);
8145 static int task_clock_event_add(struct perf_event *event, int flags)
8147 if (flags & PERF_EF_START)
8148 task_clock_event_start(event, flags);
8149 perf_event_update_userpage(event);
8154 static void task_clock_event_del(struct perf_event *event, int flags)
8156 task_clock_event_stop(event, PERF_EF_UPDATE);
8159 static void task_clock_event_read(struct perf_event *event)
8161 u64 now = perf_clock();
8162 u64 delta = now - event->ctx->timestamp;
8163 u64 time = event->ctx->time + delta;
8165 task_clock_event_update(event, time);
8168 static int task_clock_event_init(struct perf_event *event)
8170 if (event->attr.type != PERF_TYPE_SOFTWARE)
8173 if (event->attr.config != PERF_COUNT_SW_TASK_CLOCK)
8177 * no branch sampling for software events
8179 if (has_branch_stack(event))
8182 perf_swevent_init_hrtimer(event);
8187 static struct pmu perf_task_clock = {
8188 .task_ctx_nr = perf_sw_context,
8190 .capabilities = PERF_PMU_CAP_NO_NMI,
8192 .event_init = task_clock_event_init,
8193 .add = task_clock_event_add,
8194 .del = task_clock_event_del,
8195 .start = task_clock_event_start,
8196 .stop = task_clock_event_stop,
8197 .read = task_clock_event_read,
8200 static void perf_pmu_nop_void(struct pmu *pmu)
8204 static void perf_pmu_nop_txn(struct pmu *pmu, unsigned int flags)
8208 static int perf_pmu_nop_int(struct pmu *pmu)
8213 static DEFINE_PER_CPU(unsigned int, nop_txn_flags);
8215 static void perf_pmu_start_txn(struct pmu *pmu, unsigned int flags)
8217 __this_cpu_write(nop_txn_flags, flags);
8219 if (flags & ~PERF_PMU_TXN_ADD)
8222 perf_pmu_disable(pmu);
8225 static int perf_pmu_commit_txn(struct pmu *pmu)
8227 unsigned int flags = __this_cpu_read(nop_txn_flags);
8229 __this_cpu_write(nop_txn_flags, 0);
8231 if (flags & ~PERF_PMU_TXN_ADD)
8234 perf_pmu_enable(pmu);
8238 static void perf_pmu_cancel_txn(struct pmu *pmu)
8240 unsigned int flags = __this_cpu_read(nop_txn_flags);
8242 __this_cpu_write(nop_txn_flags, 0);
8244 if (flags & ~PERF_PMU_TXN_ADD)
8247 perf_pmu_enable(pmu);
8250 static int perf_event_idx_default(struct perf_event *event)
8256 * Ensures all contexts with the same task_ctx_nr have the same
8257 * pmu_cpu_context too.
8259 static struct perf_cpu_context __percpu *find_pmu_context(int ctxn)
8266 list_for_each_entry(pmu, &pmus, entry) {
8267 if (pmu->task_ctx_nr == ctxn)
8268 return pmu->pmu_cpu_context;
8274 static void update_pmu_context(struct pmu *pmu, struct pmu *old_pmu)
8278 for_each_possible_cpu(cpu) {
8279 struct perf_cpu_context *cpuctx;
8281 cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
8283 if (cpuctx->unique_pmu == old_pmu)
8284 cpuctx->unique_pmu = pmu;
8288 static void free_pmu_context(struct pmu *pmu)
8292 mutex_lock(&pmus_lock);
8294 * Like a real lame refcount.
8296 list_for_each_entry(i, &pmus, entry) {
8297 if (i->pmu_cpu_context == pmu->pmu_cpu_context) {
8298 update_pmu_context(i, pmu);
8303 free_percpu(pmu->pmu_cpu_context);
8305 mutex_unlock(&pmus_lock);
8309 * Let userspace know that this PMU supports address range filtering:
8311 static ssize_t nr_addr_filters_show(struct device *dev,
8312 struct device_attribute *attr,
8315 struct pmu *pmu = dev_get_drvdata(dev);
8317 return snprintf(page, PAGE_SIZE - 1, "%d\n", pmu->nr_addr_filters);
8319 DEVICE_ATTR_RO(nr_addr_filters);
8321 static struct idr pmu_idr;
8324 type_show(struct device *dev, struct device_attribute *attr, char *page)
8326 struct pmu *pmu = dev_get_drvdata(dev);
8328 return snprintf(page, PAGE_SIZE-1, "%d\n", pmu->type);
8330 static DEVICE_ATTR_RO(type);
8333 perf_event_mux_interval_ms_show(struct device *dev,
8334 struct device_attribute *attr,
8337 struct pmu *pmu = dev_get_drvdata(dev);
8339 return snprintf(page, PAGE_SIZE-1, "%d\n", pmu->hrtimer_interval_ms);
8342 static DEFINE_MUTEX(mux_interval_mutex);
8345 perf_event_mux_interval_ms_store(struct device *dev,
8346 struct device_attribute *attr,
8347 const char *buf, size_t count)
8349 struct pmu *pmu = dev_get_drvdata(dev);
8350 int timer, cpu, ret;
8352 ret = kstrtoint(buf, 0, &timer);
8359 /* same value, noting to do */
8360 if (timer == pmu->hrtimer_interval_ms)
8363 mutex_lock(&mux_interval_mutex);
8364 pmu->hrtimer_interval_ms = timer;
8366 /* update all cpuctx for this PMU */
8368 for_each_online_cpu(cpu) {
8369 struct perf_cpu_context *cpuctx;
8370 cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
8371 cpuctx->hrtimer_interval = ns_to_ktime(NSEC_PER_MSEC * timer);
8373 cpu_function_call(cpu,
8374 (remote_function_f)perf_mux_hrtimer_restart, cpuctx);
8377 mutex_unlock(&mux_interval_mutex);
8381 static DEVICE_ATTR_RW(perf_event_mux_interval_ms);
8383 static struct attribute *pmu_dev_attrs[] = {
8384 &dev_attr_type.attr,
8385 &dev_attr_perf_event_mux_interval_ms.attr,
8388 ATTRIBUTE_GROUPS(pmu_dev);
8390 static int pmu_bus_running;
8391 static struct bus_type pmu_bus = {
8392 .name = "event_source",
8393 .dev_groups = pmu_dev_groups,
8396 static void pmu_dev_release(struct device *dev)
8401 static int pmu_dev_alloc(struct pmu *pmu)
8405 pmu->dev = kzalloc(sizeof(struct device), GFP_KERNEL);
8409 pmu->dev->groups = pmu->attr_groups;
8410 device_initialize(pmu->dev);
8411 ret = dev_set_name(pmu->dev, "%s", pmu->name);
8415 dev_set_drvdata(pmu->dev, pmu);
8416 pmu->dev->bus = &pmu_bus;
8417 pmu->dev->release = pmu_dev_release;
8418 ret = device_add(pmu->dev);
8422 /* For PMUs with address filters, throw in an extra attribute: */
8423 if (pmu->nr_addr_filters)
8424 ret = device_create_file(pmu->dev, &dev_attr_nr_addr_filters);
8433 device_del(pmu->dev);
8436 put_device(pmu->dev);
8440 static struct lock_class_key cpuctx_mutex;
8441 static struct lock_class_key cpuctx_lock;
8443 int perf_pmu_register(struct pmu *pmu, const char *name, int type)
8447 mutex_lock(&pmus_lock);
8449 pmu->pmu_disable_count = alloc_percpu(int);
8450 if (!pmu->pmu_disable_count)
8459 type = idr_alloc(&pmu_idr, pmu, PERF_TYPE_MAX, 0, GFP_KERNEL);
8467 if (pmu_bus_running) {
8468 ret = pmu_dev_alloc(pmu);
8474 if (pmu->task_ctx_nr == perf_hw_context) {
8475 static int hw_context_taken = 0;
8478 * Other than systems with heterogeneous CPUs, it never makes
8479 * sense for two PMUs to share perf_hw_context. PMUs which are
8480 * uncore must use perf_invalid_context.
8482 if (WARN_ON_ONCE(hw_context_taken &&
8483 !(pmu->capabilities & PERF_PMU_CAP_HETEROGENEOUS_CPUS)))
8484 pmu->task_ctx_nr = perf_invalid_context;
8486 hw_context_taken = 1;
8489 pmu->pmu_cpu_context = find_pmu_context(pmu->task_ctx_nr);
8490 if (pmu->pmu_cpu_context)
8491 goto got_cpu_context;
8494 pmu->pmu_cpu_context = alloc_percpu(struct perf_cpu_context);
8495 if (!pmu->pmu_cpu_context)
8498 for_each_possible_cpu(cpu) {
8499 struct perf_cpu_context *cpuctx;
8501 cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
8502 __perf_event_init_context(&cpuctx->ctx);
8503 lockdep_set_class(&cpuctx->ctx.mutex, &cpuctx_mutex);
8504 lockdep_set_class(&cpuctx->ctx.lock, &cpuctx_lock);
8505 cpuctx->ctx.pmu = pmu;
8507 __perf_mux_hrtimer_init(cpuctx, cpu);
8509 cpuctx->unique_pmu = pmu;
8513 if (!pmu->start_txn) {
8514 if (pmu->pmu_enable) {
8516 * If we have pmu_enable/pmu_disable calls, install
8517 * transaction stubs that use that to try and batch
8518 * hardware accesses.
8520 pmu->start_txn = perf_pmu_start_txn;
8521 pmu->commit_txn = perf_pmu_commit_txn;
8522 pmu->cancel_txn = perf_pmu_cancel_txn;
8524 pmu->start_txn = perf_pmu_nop_txn;
8525 pmu->commit_txn = perf_pmu_nop_int;
8526 pmu->cancel_txn = perf_pmu_nop_void;
8530 if (!pmu->pmu_enable) {
8531 pmu->pmu_enable = perf_pmu_nop_void;
8532 pmu->pmu_disable = perf_pmu_nop_void;
8535 if (!pmu->event_idx)
8536 pmu->event_idx = perf_event_idx_default;
8538 list_add_rcu(&pmu->entry, &pmus);
8539 atomic_set(&pmu->exclusive_cnt, 0);
8542 mutex_unlock(&pmus_lock);
8547 device_del(pmu->dev);
8548 put_device(pmu->dev);
8551 if (pmu->type >= PERF_TYPE_MAX)
8552 idr_remove(&pmu_idr, pmu->type);
8555 free_percpu(pmu->pmu_disable_count);
8558 EXPORT_SYMBOL_GPL(perf_pmu_register);
8560 void perf_pmu_unregister(struct pmu *pmu)
8562 mutex_lock(&pmus_lock);
8563 list_del_rcu(&pmu->entry);
8564 mutex_unlock(&pmus_lock);
8567 * We dereference the pmu list under both SRCU and regular RCU, so
8568 * synchronize against both of those.
8570 synchronize_srcu(&pmus_srcu);
8573 free_percpu(pmu->pmu_disable_count);
8574 if (pmu->type >= PERF_TYPE_MAX)
8575 idr_remove(&pmu_idr, pmu->type);
8576 if (pmu->nr_addr_filters)
8577 device_remove_file(pmu->dev, &dev_attr_nr_addr_filters);
8578 device_del(pmu->dev);
8579 put_device(pmu->dev);
8580 free_pmu_context(pmu);
8582 EXPORT_SYMBOL_GPL(perf_pmu_unregister);
8584 static int perf_try_init_event(struct pmu *pmu, struct perf_event *event)
8586 struct perf_event_context *ctx = NULL;
8589 if (!try_module_get(pmu->module))
8592 if (event->group_leader != event) {
8594 * This ctx->mutex can nest when we're called through
8595 * inheritance. See the perf_event_ctx_lock_nested() comment.
8597 ctx = perf_event_ctx_lock_nested(event->group_leader,
8598 SINGLE_DEPTH_NESTING);
8603 ret = pmu->event_init(event);
8606 perf_event_ctx_unlock(event->group_leader, ctx);
8609 module_put(pmu->module);
8614 static struct pmu *perf_init_event(struct perf_event *event)
8616 struct pmu *pmu = NULL;
8620 idx = srcu_read_lock(&pmus_srcu);
8623 pmu = idr_find(&pmu_idr, event->attr.type);
8626 ret = perf_try_init_event(pmu, event);
8632 list_for_each_entry_rcu(pmu, &pmus, entry) {
8633 ret = perf_try_init_event(pmu, event);
8637 if (ret != -ENOENT) {
8642 pmu = ERR_PTR(-ENOENT);
8644 srcu_read_unlock(&pmus_srcu, idx);
8649 static void account_event_cpu(struct perf_event *event, int cpu)
8654 if (is_cgroup_event(event))
8655 atomic_inc(&per_cpu(perf_cgroup_events, cpu));
8658 /* Freq events need the tick to stay alive (see perf_event_task_tick). */
8659 static void account_freq_event_nohz(void)
8661 #ifdef CONFIG_NO_HZ_FULL
8662 /* Lock so we don't race with concurrent unaccount */
8663 spin_lock(&nr_freq_lock);
8664 if (atomic_inc_return(&nr_freq_events) == 1)
8665 tick_nohz_dep_set(TICK_DEP_BIT_PERF_EVENTS);
8666 spin_unlock(&nr_freq_lock);
8670 static void account_freq_event(void)
8672 if (tick_nohz_full_enabled())
8673 account_freq_event_nohz();
8675 atomic_inc(&nr_freq_events);
8679 static void account_event(struct perf_event *event)
8686 if (event->attach_state & PERF_ATTACH_TASK)
8688 if (event->attr.mmap || event->attr.mmap_data)
8689 atomic_inc(&nr_mmap_events);
8690 if (event->attr.comm)
8691 atomic_inc(&nr_comm_events);
8692 if (event->attr.task)
8693 atomic_inc(&nr_task_events);
8694 if (event->attr.freq)
8695 account_freq_event();
8696 if (event->attr.context_switch) {
8697 atomic_inc(&nr_switch_events);
8700 if (has_branch_stack(event))
8702 if (is_cgroup_event(event))
8706 if (atomic_inc_not_zero(&perf_sched_count))
8709 mutex_lock(&perf_sched_mutex);
8710 if (!atomic_read(&perf_sched_count)) {
8711 static_branch_enable(&perf_sched_events);
8713 * Guarantee that all CPUs observe they key change and
8714 * call the perf scheduling hooks before proceeding to
8715 * install events that need them.
8717 synchronize_sched();
8720 * Now that we have waited for the sync_sched(), allow further
8721 * increments to by-pass the mutex.
8723 atomic_inc(&perf_sched_count);
8724 mutex_unlock(&perf_sched_mutex);
8728 account_event_cpu(event, event->cpu);
8732 * Allocate and initialize a event structure
8734 static struct perf_event *
8735 perf_event_alloc(struct perf_event_attr *attr, int cpu,
8736 struct task_struct *task,
8737 struct perf_event *group_leader,
8738 struct perf_event *parent_event,
8739 perf_overflow_handler_t overflow_handler,
8740 void *context, int cgroup_fd)
8743 struct perf_event *event;
8744 struct hw_perf_event *hwc;
8747 if ((unsigned)cpu >= nr_cpu_ids) {
8748 if (!task || cpu != -1)
8749 return ERR_PTR(-EINVAL);
8752 event = kzalloc(sizeof(*event), GFP_KERNEL);
8754 return ERR_PTR(-ENOMEM);
8757 * Single events are their own group leaders, with an
8758 * empty sibling list:
8761 group_leader = event;
8763 mutex_init(&event->child_mutex);
8764 INIT_LIST_HEAD(&event->child_list);
8766 INIT_LIST_HEAD(&event->group_entry);
8767 INIT_LIST_HEAD(&event->event_entry);
8768 INIT_LIST_HEAD(&event->sibling_list);
8769 INIT_LIST_HEAD(&event->rb_entry);
8770 INIT_LIST_HEAD(&event->active_entry);
8771 INIT_LIST_HEAD(&event->addr_filters.list);
8772 INIT_HLIST_NODE(&event->hlist_entry);
8775 init_waitqueue_head(&event->waitq);
8776 init_irq_work(&event->pending, perf_pending_event);
8778 mutex_init(&event->mmap_mutex);
8779 raw_spin_lock_init(&event->addr_filters.lock);
8781 atomic_long_set(&event->refcount, 1);
8783 event->attr = *attr;
8784 event->group_leader = group_leader;
8788 event->parent = parent_event;
8790 event->ns = get_pid_ns(task_active_pid_ns(current));
8791 event->id = atomic64_inc_return(&perf_event_id);
8793 event->state = PERF_EVENT_STATE_INACTIVE;
8796 event->attach_state = PERF_ATTACH_TASK;
8798 * XXX pmu::event_init needs to know what task to account to
8799 * and we cannot use the ctx information because we need the
8800 * pmu before we get a ctx.
8802 event->hw.target = task;
8805 event->clock = &local_clock;
8807 event->clock = parent_event->clock;
8809 if (!overflow_handler && parent_event) {
8810 overflow_handler = parent_event->overflow_handler;
8811 context = parent_event->overflow_handler_context;
8814 if (overflow_handler) {
8815 event->overflow_handler = overflow_handler;
8816 event->overflow_handler_context = context;
8817 } else if (is_write_backward(event)){
8818 event->overflow_handler = perf_event_output_backward;
8819 event->overflow_handler_context = NULL;
8821 event->overflow_handler = perf_event_output_forward;
8822 event->overflow_handler_context = NULL;
8825 perf_event__state_init(event);
8830 hwc->sample_period = attr->sample_period;
8831 if (attr->freq && attr->sample_freq)
8832 hwc->sample_period = 1;
8833 hwc->last_period = hwc->sample_period;
8835 local64_set(&hwc->period_left, hwc->sample_period);
8838 * we currently do not support PERF_FORMAT_GROUP on inherited events
8840 if (attr->inherit && (attr->read_format & PERF_FORMAT_GROUP))
8843 if (!has_branch_stack(event))
8844 event->attr.branch_sample_type = 0;
8846 if (cgroup_fd != -1) {
8847 err = perf_cgroup_connect(cgroup_fd, event, attr, group_leader);
8852 pmu = perf_init_event(event);
8855 else if (IS_ERR(pmu)) {
8860 err = exclusive_event_init(event);
8864 if (has_addr_filter(event)) {
8865 event->addr_filters_offs = kcalloc(pmu->nr_addr_filters,
8866 sizeof(unsigned long),
8868 if (!event->addr_filters_offs)
8871 /* force hw sync on the address filters */
8872 event->addr_filters_gen = 1;
8875 if (!event->parent) {
8876 if (event->attr.sample_type & PERF_SAMPLE_CALLCHAIN) {
8877 err = get_callchain_buffers();
8879 goto err_addr_filters;
8883 /* symmetric to unaccount_event() in _free_event() */
8884 account_event(event);
8889 kfree(event->addr_filters_offs);
8892 exclusive_event_destroy(event);
8896 event->destroy(event);
8897 module_put(pmu->module);
8899 if (is_cgroup_event(event))
8900 perf_detach_cgroup(event);
8902 put_pid_ns(event->ns);
8905 return ERR_PTR(err);
8908 static int perf_copy_attr(struct perf_event_attr __user *uattr,
8909 struct perf_event_attr *attr)
8914 if (!access_ok(VERIFY_WRITE, uattr, PERF_ATTR_SIZE_VER0))
8918 * zero the full structure, so that a short copy will be nice.
8920 memset(attr, 0, sizeof(*attr));
8922 ret = get_user(size, &uattr->size);
8926 if (size > PAGE_SIZE) /* silly large */
8929 if (!size) /* abi compat */
8930 size = PERF_ATTR_SIZE_VER0;
8932 if (size < PERF_ATTR_SIZE_VER0)
8936 * If we're handed a bigger struct than we know of,
8937 * ensure all the unknown bits are 0 - i.e. new
8938 * user-space does not rely on any kernel feature
8939 * extensions we dont know about yet.
8941 if (size > sizeof(*attr)) {
8942 unsigned char __user *addr;
8943 unsigned char __user *end;
8946 addr = (void __user *)uattr + sizeof(*attr);
8947 end = (void __user *)uattr + size;
8949 for (; addr < end; addr++) {
8950 ret = get_user(val, addr);
8956 size = sizeof(*attr);
8959 ret = copy_from_user(attr, uattr, size);
8963 if (attr->__reserved_1)
8966 if (attr->sample_type & ~(PERF_SAMPLE_MAX-1))
8969 if (attr->read_format & ~(PERF_FORMAT_MAX-1))
8972 if (attr->sample_type & PERF_SAMPLE_BRANCH_STACK) {
8973 u64 mask = attr->branch_sample_type;
8975 /* only using defined bits */
8976 if (mask & ~(PERF_SAMPLE_BRANCH_MAX-1))
8979 /* at least one branch bit must be set */
8980 if (!(mask & ~PERF_SAMPLE_BRANCH_PLM_ALL))
8983 /* propagate priv level, when not set for branch */
8984 if (!(mask & PERF_SAMPLE_BRANCH_PLM_ALL)) {
8986 /* exclude_kernel checked on syscall entry */
8987 if (!attr->exclude_kernel)
8988 mask |= PERF_SAMPLE_BRANCH_KERNEL;
8990 if (!attr->exclude_user)
8991 mask |= PERF_SAMPLE_BRANCH_USER;
8993 if (!attr->exclude_hv)
8994 mask |= PERF_SAMPLE_BRANCH_HV;
8996 * adjust user setting (for HW filter setup)
8998 attr->branch_sample_type = mask;
9000 /* privileged levels capture (kernel, hv): check permissions */
9001 if ((mask & PERF_SAMPLE_BRANCH_PERM_PLM)
9002 && perf_paranoid_kernel() && !capable(CAP_SYS_ADMIN))
9006 if (attr->sample_type & PERF_SAMPLE_REGS_USER) {
9007 ret = perf_reg_validate(attr->sample_regs_user);
9012 if (attr->sample_type & PERF_SAMPLE_STACK_USER) {
9013 if (!arch_perf_have_user_stack_dump())
9017 * We have __u32 type for the size, but so far
9018 * we can only use __u16 as maximum due to the
9019 * __u16 sample size limit.
9021 if (attr->sample_stack_user >= USHRT_MAX)
9023 else if (!IS_ALIGNED(attr->sample_stack_user, sizeof(u64)))
9027 if (attr->sample_type & PERF_SAMPLE_REGS_INTR)
9028 ret = perf_reg_validate(attr->sample_regs_intr);
9033 put_user(sizeof(*attr), &uattr->size);
9039 perf_event_set_output(struct perf_event *event, struct perf_event *output_event)
9041 struct ring_buffer *rb = NULL;
9047 /* don't allow circular references */
9048 if (event == output_event)
9052 * Don't allow cross-cpu buffers
9054 if (output_event->cpu != event->cpu)
9058 * If its not a per-cpu rb, it must be the same task.
9060 if (output_event->cpu == -1 && output_event->ctx != event->ctx)
9064 * Mixing clocks in the same buffer is trouble you don't need.
9066 if (output_event->clock != event->clock)
9070 * Either writing ring buffer from beginning or from end.
9071 * Mixing is not allowed.
9073 if (is_write_backward(output_event) != is_write_backward(event))
9077 * If both events generate aux data, they must be on the same PMU
9079 if (has_aux(event) && has_aux(output_event) &&
9080 event->pmu != output_event->pmu)
9084 mutex_lock(&event->mmap_mutex);
9085 /* Can't redirect output if we've got an active mmap() */
9086 if (atomic_read(&event->mmap_count))
9090 /* get the rb we want to redirect to */
9091 rb = ring_buffer_get(output_event);
9096 ring_buffer_attach(event, rb);
9100 mutex_unlock(&event->mmap_mutex);
9106 static void mutex_lock_double(struct mutex *a, struct mutex *b)
9112 mutex_lock_nested(b, SINGLE_DEPTH_NESTING);
9115 static int perf_event_set_clock(struct perf_event *event, clockid_t clk_id)
9117 bool nmi_safe = false;
9120 case CLOCK_MONOTONIC:
9121 event->clock = &ktime_get_mono_fast_ns;
9125 case CLOCK_MONOTONIC_RAW:
9126 event->clock = &ktime_get_raw_fast_ns;
9130 case CLOCK_REALTIME:
9131 event->clock = &ktime_get_real_ns;
9134 case CLOCK_BOOTTIME:
9135 event->clock = &ktime_get_boot_ns;
9139 event->clock = &ktime_get_tai_ns;
9146 if (!nmi_safe && !(event->pmu->capabilities & PERF_PMU_CAP_NO_NMI))
9153 * sys_perf_event_open - open a performance event, associate it to a task/cpu
9155 * @attr_uptr: event_id type attributes for monitoring/sampling
9158 * @group_fd: group leader event fd
9160 SYSCALL_DEFINE5(perf_event_open,
9161 struct perf_event_attr __user *, attr_uptr,
9162 pid_t, pid, int, cpu, int, group_fd, unsigned long, flags)
9164 struct perf_event *group_leader = NULL, *output_event = NULL;
9165 struct perf_event *event, *sibling;
9166 struct perf_event_attr attr;
9167 struct perf_event_context *ctx, *uninitialized_var(gctx);
9168 struct file *event_file = NULL;
9169 struct fd group = {NULL, 0};
9170 struct task_struct *task = NULL;
9175 int f_flags = O_RDWR;
9178 /* for future expandability... */
9179 if (flags & ~PERF_FLAG_ALL)
9182 err = perf_copy_attr(attr_uptr, &attr);
9186 if (!attr.exclude_kernel) {
9187 if (perf_paranoid_kernel() && !capable(CAP_SYS_ADMIN))
9192 if (attr.sample_freq > sysctl_perf_event_sample_rate)
9195 if (attr.sample_period & (1ULL << 63))
9200 * In cgroup mode, the pid argument is used to pass the fd
9201 * opened to the cgroup directory in cgroupfs. The cpu argument
9202 * designates the cpu on which to monitor threads from that
9205 if ((flags & PERF_FLAG_PID_CGROUP) && (pid == -1 || cpu == -1))
9208 if (flags & PERF_FLAG_FD_CLOEXEC)
9209 f_flags |= O_CLOEXEC;
9211 event_fd = get_unused_fd_flags(f_flags);
9215 if (group_fd != -1) {
9216 err = perf_fget_light(group_fd, &group);
9219 group_leader = group.file->private_data;
9220 if (flags & PERF_FLAG_FD_OUTPUT)
9221 output_event = group_leader;
9222 if (flags & PERF_FLAG_FD_NO_GROUP)
9223 group_leader = NULL;
9226 if (pid != -1 && !(flags & PERF_FLAG_PID_CGROUP)) {
9227 task = find_lively_task_by_vpid(pid);
9229 err = PTR_ERR(task);
9234 if (task && group_leader &&
9235 group_leader->attr.inherit != attr.inherit) {
9243 err = mutex_lock_interruptible(&task->signal->cred_guard_mutex);
9248 * Reuse ptrace permission checks for now.
9250 * We must hold cred_guard_mutex across this and any potential
9251 * perf_install_in_context() call for this new event to
9252 * serialize against exec() altering our credentials (and the
9253 * perf_event_exit_task() that could imply).
9256 if (!ptrace_may_access(task, PTRACE_MODE_READ_REALCREDS))
9260 if (flags & PERF_FLAG_PID_CGROUP)
9263 event = perf_event_alloc(&attr, cpu, task, group_leader, NULL,
9264 NULL, NULL, cgroup_fd);
9265 if (IS_ERR(event)) {
9266 err = PTR_ERR(event);
9270 if (is_sampling_event(event)) {
9271 if (event->pmu->capabilities & PERF_PMU_CAP_NO_INTERRUPT) {
9278 * Special case software events and allow them to be part of
9279 * any hardware group.
9283 if (attr.use_clockid) {
9284 err = perf_event_set_clock(event, attr.clockid);
9290 (is_software_event(event) != is_software_event(group_leader))) {
9291 if (is_software_event(event)) {
9293 * If event and group_leader are not both a software
9294 * event, and event is, then group leader is not.
9296 * Allow the addition of software events to !software
9297 * groups, this is safe because software events never
9300 pmu = group_leader->pmu;
9301 } else if (is_software_event(group_leader) &&
9302 (group_leader->group_flags & PERF_GROUP_SOFTWARE)) {
9304 * In case the group is a pure software group, and we
9305 * try to add a hardware event, move the whole group to
9306 * the hardware context.
9313 * Get the target context (task or percpu):
9315 ctx = find_get_context(pmu, task, event);
9321 if ((pmu->capabilities & PERF_PMU_CAP_EXCLUSIVE) && group_leader) {
9327 * Look up the group leader (we will attach this event to it):
9333 * Do not allow a recursive hierarchy (this new sibling
9334 * becoming part of another group-sibling):
9336 if (group_leader->group_leader != group_leader)
9339 /* All events in a group should have the same clock */
9340 if (group_leader->clock != event->clock)
9344 * Do not allow to attach to a group in a different
9345 * task or CPU context:
9349 * Make sure we're both on the same task, or both
9352 if (group_leader->ctx->task != ctx->task)
9356 * Make sure we're both events for the same CPU;
9357 * grouping events for different CPUs is broken; since
9358 * you can never concurrently schedule them anyhow.
9360 if (group_leader->cpu != event->cpu)
9363 if (group_leader->ctx != ctx)
9368 * Only a group leader can be exclusive or pinned
9370 if (attr.exclusive || attr.pinned)
9375 err = perf_event_set_output(event, output_event);
9380 event_file = anon_inode_getfile("[perf_event]", &perf_fops, event,
9382 if (IS_ERR(event_file)) {
9383 err = PTR_ERR(event_file);
9389 gctx = group_leader->ctx;
9390 mutex_lock_double(&gctx->mutex, &ctx->mutex);
9391 if (gctx->task == TASK_TOMBSTONE) {
9396 mutex_lock(&ctx->mutex);
9399 if (ctx->task == TASK_TOMBSTONE) {
9404 if (!perf_event_validate_size(event)) {
9410 * Must be under the same ctx::mutex as perf_install_in_context(),
9411 * because we need to serialize with concurrent event creation.
9413 if (!exclusive_event_installable(event, ctx)) {
9414 /* exclusive and group stuff are assumed mutually exclusive */
9415 WARN_ON_ONCE(move_group);
9421 WARN_ON_ONCE(ctx->parent_ctx);
9424 * This is the point on no return; we cannot fail hereafter. This is
9425 * where we start modifying current state.
9430 * See perf_event_ctx_lock() for comments on the details
9431 * of swizzling perf_event::ctx.
9433 perf_remove_from_context(group_leader, 0);
9435 list_for_each_entry(sibling, &group_leader->sibling_list,
9437 perf_remove_from_context(sibling, 0);
9442 * Wait for everybody to stop referencing the events through
9443 * the old lists, before installing it on new lists.
9448 * Install the group siblings before the group leader.
9450 * Because a group leader will try and install the entire group
9451 * (through the sibling list, which is still in-tact), we can
9452 * end up with siblings installed in the wrong context.
9454 * By installing siblings first we NO-OP because they're not
9455 * reachable through the group lists.
9457 list_for_each_entry(sibling, &group_leader->sibling_list,
9459 perf_event__state_init(sibling);
9460 perf_install_in_context(ctx, sibling, sibling->cpu);
9465 * Removing from the context ends up with disabled
9466 * event. What we want here is event in the initial
9467 * startup state, ready to be add into new context.
9469 perf_event__state_init(group_leader);
9470 perf_install_in_context(ctx, group_leader, group_leader->cpu);
9474 * Now that all events are installed in @ctx, nothing
9475 * references @gctx anymore, so drop the last reference we have
9482 * Precalculate sample_data sizes; do while holding ctx::mutex such
9483 * that we're serialized against further additions and before
9484 * perf_install_in_context() which is the point the event is active and
9485 * can use these values.
9487 perf_event__header_size(event);
9488 perf_event__id_header_size(event);
9490 event->owner = current;
9492 perf_install_in_context(ctx, event, event->cpu);
9493 perf_unpin_context(ctx);
9496 mutex_unlock(&gctx->mutex);
9497 mutex_unlock(&ctx->mutex);
9500 mutex_unlock(&task->signal->cred_guard_mutex);
9501 put_task_struct(task);
9506 mutex_lock(¤t->perf_event_mutex);
9507 list_add_tail(&event->owner_entry, ¤t->perf_event_list);
9508 mutex_unlock(¤t->perf_event_mutex);
9511 * Drop the reference on the group_event after placing the
9512 * new event on the sibling_list. This ensures destruction
9513 * of the group leader will find the pointer to itself in
9514 * perf_group_detach().
9517 fd_install(event_fd, event_file);
9522 mutex_unlock(&gctx->mutex);
9523 mutex_unlock(&ctx->mutex);
9527 perf_unpin_context(ctx);
9531 * If event_file is set, the fput() above will have called ->release()
9532 * and that will take care of freeing the event.
9538 mutex_unlock(&task->signal->cred_guard_mutex);
9543 put_task_struct(task);
9547 put_unused_fd(event_fd);
9552 * perf_event_create_kernel_counter
9554 * @attr: attributes of the counter to create
9555 * @cpu: cpu in which the counter is bound
9556 * @task: task to profile (NULL for percpu)
9559 perf_event_create_kernel_counter(struct perf_event_attr *attr, int cpu,
9560 struct task_struct *task,
9561 perf_overflow_handler_t overflow_handler,
9564 struct perf_event_context *ctx;
9565 struct perf_event *event;
9569 * Get the target context (task or percpu):
9572 event = perf_event_alloc(attr, cpu, task, NULL, NULL,
9573 overflow_handler, context, -1);
9574 if (IS_ERR(event)) {
9575 err = PTR_ERR(event);
9579 /* Mark owner so we could distinguish it from user events. */
9580 event->owner = TASK_TOMBSTONE;
9582 ctx = find_get_context(event->pmu, task, event);
9588 WARN_ON_ONCE(ctx->parent_ctx);
9589 mutex_lock(&ctx->mutex);
9590 if (ctx->task == TASK_TOMBSTONE) {
9595 if (!exclusive_event_installable(event, ctx)) {
9600 perf_install_in_context(ctx, event, cpu);
9601 perf_unpin_context(ctx);
9602 mutex_unlock(&ctx->mutex);
9607 mutex_unlock(&ctx->mutex);
9608 perf_unpin_context(ctx);
9613 return ERR_PTR(err);
9615 EXPORT_SYMBOL_GPL(perf_event_create_kernel_counter);
9617 void perf_pmu_migrate_context(struct pmu *pmu, int src_cpu, int dst_cpu)
9619 struct perf_event_context *src_ctx;
9620 struct perf_event_context *dst_ctx;
9621 struct perf_event *event, *tmp;
9624 src_ctx = &per_cpu_ptr(pmu->pmu_cpu_context, src_cpu)->ctx;
9625 dst_ctx = &per_cpu_ptr(pmu->pmu_cpu_context, dst_cpu)->ctx;
9628 * See perf_event_ctx_lock() for comments on the details
9629 * of swizzling perf_event::ctx.
9631 mutex_lock_double(&src_ctx->mutex, &dst_ctx->mutex);
9632 list_for_each_entry_safe(event, tmp, &src_ctx->event_list,
9634 perf_remove_from_context(event, 0);
9635 unaccount_event_cpu(event, src_cpu);
9637 list_add(&event->migrate_entry, &events);
9641 * Wait for the events to quiesce before re-instating them.
9646 * Re-instate events in 2 passes.
9648 * Skip over group leaders and only install siblings on this first
9649 * pass, siblings will not get enabled without a leader, however a
9650 * leader will enable its siblings, even if those are still on the old
9653 list_for_each_entry_safe(event, tmp, &events, migrate_entry) {
9654 if (event->group_leader == event)
9657 list_del(&event->migrate_entry);
9658 if (event->state >= PERF_EVENT_STATE_OFF)
9659 event->state = PERF_EVENT_STATE_INACTIVE;
9660 account_event_cpu(event, dst_cpu);
9661 perf_install_in_context(dst_ctx, event, dst_cpu);
9666 * Once all the siblings are setup properly, install the group leaders
9669 list_for_each_entry_safe(event, tmp, &events, migrate_entry) {
9670 list_del(&event->migrate_entry);
9671 if (event->state >= PERF_EVENT_STATE_OFF)
9672 event->state = PERF_EVENT_STATE_INACTIVE;
9673 account_event_cpu(event, dst_cpu);
9674 perf_install_in_context(dst_ctx, event, dst_cpu);
9677 mutex_unlock(&dst_ctx->mutex);
9678 mutex_unlock(&src_ctx->mutex);
9680 EXPORT_SYMBOL_GPL(perf_pmu_migrate_context);
9682 static void sync_child_event(struct perf_event *child_event,
9683 struct task_struct *child)
9685 struct perf_event *parent_event = child_event->parent;
9688 if (child_event->attr.inherit_stat)
9689 perf_event_read_event(child_event, child);
9691 child_val = perf_event_count(child_event);
9694 * Add back the child's count to the parent's count:
9696 atomic64_add(child_val, &parent_event->child_count);
9697 atomic64_add(child_event->total_time_enabled,
9698 &parent_event->child_total_time_enabled);
9699 atomic64_add(child_event->total_time_running,
9700 &parent_event->child_total_time_running);
9704 perf_event_exit_event(struct perf_event *child_event,
9705 struct perf_event_context *child_ctx,
9706 struct task_struct *child)
9708 struct perf_event *parent_event = child_event->parent;
9711 * Do not destroy the 'original' grouping; because of the context
9712 * switch optimization the original events could've ended up in a
9713 * random child task.
9715 * If we were to destroy the original group, all group related
9716 * operations would cease to function properly after this random
9719 * Do destroy all inherited groups, we don't care about those
9720 * and being thorough is better.
9722 raw_spin_lock_irq(&child_ctx->lock);
9723 WARN_ON_ONCE(child_ctx->is_active);
9726 perf_group_detach(child_event);
9727 list_del_event(child_event, child_ctx);
9728 child_event->state = PERF_EVENT_STATE_EXIT; /* is_event_hup() */
9729 raw_spin_unlock_irq(&child_ctx->lock);
9732 * Parent events are governed by their filedesc, retain them.
9734 if (!parent_event) {
9735 perf_event_wakeup(child_event);
9739 * Child events can be cleaned up.
9742 sync_child_event(child_event, child);
9745 * Remove this event from the parent's list
9747 WARN_ON_ONCE(parent_event->ctx->parent_ctx);
9748 mutex_lock(&parent_event->child_mutex);
9749 list_del_init(&child_event->child_list);
9750 mutex_unlock(&parent_event->child_mutex);
9753 * Kick perf_poll() for is_event_hup().
9755 perf_event_wakeup(parent_event);
9756 free_event(child_event);
9757 put_event(parent_event);
9760 static void perf_event_exit_task_context(struct task_struct *child, int ctxn)
9762 struct perf_event_context *child_ctx, *clone_ctx = NULL;
9763 struct perf_event *child_event, *next;
9765 WARN_ON_ONCE(child != current);
9767 child_ctx = perf_pin_task_context(child, ctxn);
9772 * In order to reduce the amount of tricky in ctx tear-down, we hold
9773 * ctx::mutex over the entire thing. This serializes against almost
9774 * everything that wants to access the ctx.
9776 * The exception is sys_perf_event_open() /
9777 * perf_event_create_kernel_count() which does find_get_context()
9778 * without ctx::mutex (it cannot because of the move_group double mutex
9779 * lock thing). See the comments in perf_install_in_context().
9781 mutex_lock(&child_ctx->mutex);
9784 * In a single ctx::lock section, de-schedule the events and detach the
9785 * context from the task such that we cannot ever get it scheduled back
9788 raw_spin_lock_irq(&child_ctx->lock);
9789 task_ctx_sched_out(__get_cpu_context(child_ctx), child_ctx);
9792 * Now that the context is inactive, destroy the task <-> ctx relation
9793 * and mark the context dead.
9795 RCU_INIT_POINTER(child->perf_event_ctxp[ctxn], NULL);
9796 put_ctx(child_ctx); /* cannot be last */
9797 WRITE_ONCE(child_ctx->task, TASK_TOMBSTONE);
9798 put_task_struct(current); /* cannot be last */
9800 clone_ctx = unclone_ctx(child_ctx);
9801 raw_spin_unlock_irq(&child_ctx->lock);
9807 * Report the task dead after unscheduling the events so that we
9808 * won't get any samples after PERF_RECORD_EXIT. We can however still
9809 * get a few PERF_RECORD_READ events.
9811 perf_event_task(child, child_ctx, 0);
9813 list_for_each_entry_safe(child_event, next, &child_ctx->event_list, event_entry)
9814 perf_event_exit_event(child_event, child_ctx, child);
9816 mutex_unlock(&child_ctx->mutex);
9822 * When a child task exits, feed back event values to parent events.
9824 * Can be called with cred_guard_mutex held when called from
9825 * install_exec_creds().
9827 void perf_event_exit_task(struct task_struct *child)
9829 struct perf_event *event, *tmp;
9832 mutex_lock(&child->perf_event_mutex);
9833 list_for_each_entry_safe(event, tmp, &child->perf_event_list,
9835 list_del_init(&event->owner_entry);
9838 * Ensure the list deletion is visible before we clear
9839 * the owner, closes a race against perf_release() where
9840 * we need to serialize on the owner->perf_event_mutex.
9842 smp_store_release(&event->owner, NULL);
9844 mutex_unlock(&child->perf_event_mutex);
9846 for_each_task_context_nr(ctxn)
9847 perf_event_exit_task_context(child, ctxn);
9850 * The perf_event_exit_task_context calls perf_event_task
9851 * with child's task_ctx, which generates EXIT events for
9852 * child contexts and sets child->perf_event_ctxp[] to NULL.
9853 * At this point we need to send EXIT events to cpu contexts.
9855 perf_event_task(child, NULL, 0);
9858 static void perf_free_event(struct perf_event *event,
9859 struct perf_event_context *ctx)
9861 struct perf_event *parent = event->parent;
9863 if (WARN_ON_ONCE(!parent))
9866 mutex_lock(&parent->child_mutex);
9867 list_del_init(&event->child_list);
9868 mutex_unlock(&parent->child_mutex);
9872 raw_spin_lock_irq(&ctx->lock);
9873 perf_group_detach(event);
9874 list_del_event(event, ctx);
9875 raw_spin_unlock_irq(&ctx->lock);
9880 * Free an unexposed, unused context as created by inheritance by
9881 * perf_event_init_task below, used by fork() in case of fail.
9883 * Not all locks are strictly required, but take them anyway to be nice and
9884 * help out with the lockdep assertions.
9886 void perf_event_free_task(struct task_struct *task)
9888 struct perf_event_context *ctx;
9889 struct perf_event *event, *tmp;
9892 for_each_task_context_nr(ctxn) {
9893 ctx = task->perf_event_ctxp[ctxn];
9897 mutex_lock(&ctx->mutex);
9899 list_for_each_entry_safe(event, tmp, &ctx->pinned_groups,
9901 perf_free_event(event, ctx);
9903 list_for_each_entry_safe(event, tmp, &ctx->flexible_groups,
9905 perf_free_event(event, ctx);
9907 if (!list_empty(&ctx->pinned_groups) ||
9908 !list_empty(&ctx->flexible_groups))
9911 mutex_unlock(&ctx->mutex);
9917 void perf_event_delayed_put(struct task_struct *task)
9921 for_each_task_context_nr(ctxn)
9922 WARN_ON_ONCE(task->perf_event_ctxp[ctxn]);
9925 struct file *perf_event_get(unsigned int fd)
9929 file = fget_raw(fd);
9931 return ERR_PTR(-EBADF);
9933 if (file->f_op != &perf_fops) {
9935 return ERR_PTR(-EBADF);
9941 const struct perf_event_attr *perf_event_attrs(struct perf_event *event)
9944 return ERR_PTR(-EINVAL);
9946 return &event->attr;
9950 * inherit a event from parent task to child task:
9952 static struct perf_event *
9953 inherit_event(struct perf_event *parent_event,
9954 struct task_struct *parent,
9955 struct perf_event_context *parent_ctx,
9956 struct task_struct *child,
9957 struct perf_event *group_leader,
9958 struct perf_event_context *child_ctx)
9960 enum perf_event_active_state parent_state = parent_event->state;
9961 struct perf_event *child_event;
9962 unsigned long flags;
9965 * Instead of creating recursive hierarchies of events,
9966 * we link inherited events back to the original parent,
9967 * which has a filp for sure, which we use as the reference
9970 if (parent_event->parent)
9971 parent_event = parent_event->parent;
9973 child_event = perf_event_alloc(&parent_event->attr,
9976 group_leader, parent_event,
9978 if (IS_ERR(child_event))
9982 * is_orphaned_event() and list_add_tail(&parent_event->child_list)
9983 * must be under the same lock in order to serialize against
9984 * perf_event_release_kernel(), such that either we must observe
9985 * is_orphaned_event() or they will observe us on the child_list.
9987 mutex_lock(&parent_event->child_mutex);
9988 if (is_orphaned_event(parent_event) ||
9989 !atomic_long_inc_not_zero(&parent_event->refcount)) {
9990 mutex_unlock(&parent_event->child_mutex);
9991 free_event(child_event);
9998 * Make the child state follow the state of the parent event,
9999 * not its attr.disabled bit. We hold the parent's mutex,
10000 * so we won't race with perf_event_{en, dis}able_family.
10002 if (parent_state >= PERF_EVENT_STATE_INACTIVE)
10003 child_event->state = PERF_EVENT_STATE_INACTIVE;
10005 child_event->state = PERF_EVENT_STATE_OFF;
10007 if (parent_event->attr.freq) {
10008 u64 sample_period = parent_event->hw.sample_period;
10009 struct hw_perf_event *hwc = &child_event->hw;
10011 hwc->sample_period = sample_period;
10012 hwc->last_period = sample_period;
10014 local64_set(&hwc->period_left, sample_period);
10017 child_event->ctx = child_ctx;
10018 child_event->overflow_handler = parent_event->overflow_handler;
10019 child_event->overflow_handler_context
10020 = parent_event->overflow_handler_context;
10023 * Precalculate sample_data sizes
10025 perf_event__header_size(child_event);
10026 perf_event__id_header_size(child_event);
10029 * Link it up in the child's context:
10031 raw_spin_lock_irqsave(&child_ctx->lock, flags);
10032 add_event_to_ctx(child_event, child_ctx);
10033 raw_spin_unlock_irqrestore(&child_ctx->lock, flags);
10036 * Link this into the parent event's child list
10038 list_add_tail(&child_event->child_list, &parent_event->child_list);
10039 mutex_unlock(&parent_event->child_mutex);
10041 return child_event;
10044 static int inherit_group(struct perf_event *parent_event,
10045 struct task_struct *parent,
10046 struct perf_event_context *parent_ctx,
10047 struct task_struct *child,
10048 struct perf_event_context *child_ctx)
10050 struct perf_event *leader;
10051 struct perf_event *sub;
10052 struct perf_event *child_ctr;
10054 leader = inherit_event(parent_event, parent, parent_ctx,
10055 child, NULL, child_ctx);
10056 if (IS_ERR(leader))
10057 return PTR_ERR(leader);
10058 list_for_each_entry(sub, &parent_event->sibling_list, group_entry) {
10059 child_ctr = inherit_event(sub, parent, parent_ctx,
10060 child, leader, child_ctx);
10061 if (IS_ERR(child_ctr))
10062 return PTR_ERR(child_ctr);
10068 inherit_task_group(struct perf_event *event, struct task_struct *parent,
10069 struct perf_event_context *parent_ctx,
10070 struct task_struct *child, int ctxn,
10071 int *inherited_all)
10074 struct perf_event_context *child_ctx;
10076 if (!event->attr.inherit) {
10077 *inherited_all = 0;
10081 child_ctx = child->perf_event_ctxp[ctxn];
10084 * This is executed from the parent task context, so
10085 * inherit events that have been marked for cloning.
10086 * First allocate and initialize a context for the
10090 child_ctx = alloc_perf_context(parent_ctx->pmu, child);
10094 child->perf_event_ctxp[ctxn] = child_ctx;
10097 ret = inherit_group(event, parent, parent_ctx,
10101 *inherited_all = 0;
10107 * Initialize the perf_event context in task_struct
10109 static int perf_event_init_context(struct task_struct *child, int ctxn)
10111 struct perf_event_context *child_ctx, *parent_ctx;
10112 struct perf_event_context *cloned_ctx;
10113 struct perf_event *event;
10114 struct task_struct *parent = current;
10115 int inherited_all = 1;
10116 unsigned long flags;
10119 if (likely(!parent->perf_event_ctxp[ctxn]))
10123 * If the parent's context is a clone, pin it so it won't get
10124 * swapped under us.
10126 parent_ctx = perf_pin_task_context(parent, ctxn);
10131 * No need to check if parent_ctx != NULL here; since we saw
10132 * it non-NULL earlier, the only reason for it to become NULL
10133 * is if we exit, and since we're currently in the middle of
10134 * a fork we can't be exiting at the same time.
10138 * Lock the parent list. No need to lock the child - not PID
10139 * hashed yet and not running, so nobody can access it.
10141 mutex_lock(&parent_ctx->mutex);
10144 * We dont have to disable NMIs - we are only looking at
10145 * the list, not manipulating it:
10147 list_for_each_entry(event, &parent_ctx->pinned_groups, group_entry) {
10148 ret = inherit_task_group(event, parent, parent_ctx,
10149 child, ctxn, &inherited_all);
10155 * We can't hold ctx->lock when iterating the ->flexible_group list due
10156 * to allocations, but we need to prevent rotation because
10157 * rotate_ctx() will change the list from interrupt context.
10159 raw_spin_lock_irqsave(&parent_ctx->lock, flags);
10160 parent_ctx->rotate_disable = 1;
10161 raw_spin_unlock_irqrestore(&parent_ctx->lock, flags);
10163 list_for_each_entry(event, &parent_ctx->flexible_groups, group_entry) {
10164 ret = inherit_task_group(event, parent, parent_ctx,
10165 child, ctxn, &inherited_all);
10170 raw_spin_lock_irqsave(&parent_ctx->lock, flags);
10171 parent_ctx->rotate_disable = 0;
10173 child_ctx = child->perf_event_ctxp[ctxn];
10175 if (child_ctx && inherited_all) {
10177 * Mark the child context as a clone of the parent
10178 * context, or of whatever the parent is a clone of.
10180 * Note that if the parent is a clone, the holding of
10181 * parent_ctx->lock avoids it from being uncloned.
10183 cloned_ctx = parent_ctx->parent_ctx;
10185 child_ctx->parent_ctx = cloned_ctx;
10186 child_ctx->parent_gen = parent_ctx->parent_gen;
10188 child_ctx->parent_ctx = parent_ctx;
10189 child_ctx->parent_gen = parent_ctx->generation;
10191 get_ctx(child_ctx->parent_ctx);
10194 raw_spin_unlock_irqrestore(&parent_ctx->lock, flags);
10195 mutex_unlock(&parent_ctx->mutex);
10197 perf_unpin_context(parent_ctx);
10198 put_ctx(parent_ctx);
10204 * Initialize the perf_event context in task_struct
10206 int perf_event_init_task(struct task_struct *child)
10210 memset(child->perf_event_ctxp, 0, sizeof(child->perf_event_ctxp));
10211 mutex_init(&child->perf_event_mutex);
10212 INIT_LIST_HEAD(&child->perf_event_list);
10214 for_each_task_context_nr(ctxn) {
10215 ret = perf_event_init_context(child, ctxn);
10217 perf_event_free_task(child);
10225 static void __init perf_event_init_all_cpus(void)
10227 struct swevent_htable *swhash;
10230 for_each_possible_cpu(cpu) {
10231 swhash = &per_cpu(swevent_htable, cpu);
10232 mutex_init(&swhash->hlist_mutex);
10233 INIT_LIST_HEAD(&per_cpu(active_ctx_list, cpu));
10237 static void perf_event_init_cpu(int cpu)
10239 struct swevent_htable *swhash = &per_cpu(swevent_htable, cpu);
10241 mutex_lock(&swhash->hlist_mutex);
10242 if (swhash->hlist_refcount > 0 && !swevent_hlist_deref(swhash)) {
10243 struct swevent_hlist *hlist;
10245 hlist = kzalloc_node(sizeof(*hlist), GFP_KERNEL, cpu_to_node(cpu));
10247 rcu_assign_pointer(swhash->swevent_hlist, hlist);
10249 mutex_unlock(&swhash->hlist_mutex);
10252 #if defined CONFIG_HOTPLUG_CPU || defined CONFIG_KEXEC_CORE
10253 static void __perf_event_exit_context(void *__info)
10255 struct perf_event_context *ctx = __info;
10256 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
10257 struct perf_event *event;
10259 raw_spin_lock(&ctx->lock);
10260 list_for_each_entry(event, &ctx->event_list, event_entry)
10261 __perf_remove_from_context(event, cpuctx, ctx, (void *)DETACH_GROUP);
10262 raw_spin_unlock(&ctx->lock);
10265 static void perf_event_exit_cpu_context(int cpu)
10267 struct perf_event_context *ctx;
10271 idx = srcu_read_lock(&pmus_srcu);
10272 list_for_each_entry_rcu(pmu, &pmus, entry) {
10273 ctx = &per_cpu_ptr(pmu->pmu_cpu_context, cpu)->ctx;
10275 mutex_lock(&ctx->mutex);
10276 smp_call_function_single(cpu, __perf_event_exit_context, ctx, 1);
10277 mutex_unlock(&ctx->mutex);
10279 srcu_read_unlock(&pmus_srcu, idx);
10282 static void perf_event_exit_cpu(int cpu)
10284 perf_event_exit_cpu_context(cpu);
10287 static inline void perf_event_exit_cpu(int cpu) { }
10291 perf_reboot(struct notifier_block *notifier, unsigned long val, void *v)
10295 for_each_online_cpu(cpu)
10296 perf_event_exit_cpu(cpu);
10302 * Run the perf reboot notifier at the very last possible moment so that
10303 * the generic watchdog code runs as long as possible.
10305 static struct notifier_block perf_reboot_notifier = {
10306 .notifier_call = perf_reboot,
10307 .priority = INT_MIN,
10311 perf_cpu_notify(struct notifier_block *self, unsigned long action, void *hcpu)
10313 unsigned int cpu = (long)hcpu;
10315 switch (action & ~CPU_TASKS_FROZEN) {
10317 case CPU_UP_PREPARE:
10319 * This must be done before the CPU comes alive, because the
10320 * moment we can run tasks we can encounter (software) events.
10322 * Specifically, someone can have inherited events on kthreadd
10323 * or a pre-existing worker thread that gets re-bound.
10325 perf_event_init_cpu(cpu);
10328 case CPU_DOWN_PREPARE:
10330 * This must be done before the CPU dies because after that an
10331 * active event might want to IPI the CPU and that'll not work
10332 * so great for dead CPUs.
10334 * XXX smp_call_function_single() return -ENXIO without a warn
10335 * so we could possibly deal with this.
10337 * This is safe against new events arriving because
10338 * sys_perf_event_open() serializes against hotplug using
10339 * get_online_cpus().
10341 perf_event_exit_cpu(cpu);
10350 void __init perf_event_init(void)
10354 idr_init(&pmu_idr);
10356 perf_event_init_all_cpus();
10357 init_srcu_struct(&pmus_srcu);
10358 perf_pmu_register(&perf_swevent, "software", PERF_TYPE_SOFTWARE);
10359 perf_pmu_register(&perf_cpu_clock, NULL, -1);
10360 perf_pmu_register(&perf_task_clock, NULL, -1);
10361 perf_tp_register();
10362 perf_cpu_notifier(perf_cpu_notify);
10363 register_reboot_notifier(&perf_reboot_notifier);
10365 ret = init_hw_breakpoint();
10366 WARN(ret, "hw_breakpoint initialization failed with: %d", ret);
10369 * Build time assertion that we keep the data_head at the intended
10370 * location. IOW, validation we got the __reserved[] size right.
10372 BUILD_BUG_ON((offsetof(struct perf_event_mmap_page, data_head))
10376 ssize_t perf_event_sysfs_show(struct device *dev, struct device_attribute *attr,
10379 struct perf_pmu_events_attr *pmu_attr =
10380 container_of(attr, struct perf_pmu_events_attr, attr);
10382 if (pmu_attr->event_str)
10383 return sprintf(page, "%s\n", pmu_attr->event_str);
10387 EXPORT_SYMBOL_GPL(perf_event_sysfs_show);
10389 static int __init perf_event_sysfs_init(void)
10394 mutex_lock(&pmus_lock);
10396 ret = bus_register(&pmu_bus);
10400 list_for_each_entry(pmu, &pmus, entry) {
10401 if (!pmu->name || pmu->type < 0)
10404 ret = pmu_dev_alloc(pmu);
10405 WARN(ret, "Failed to register pmu: %s, reason %d\n", pmu->name, ret);
10407 pmu_bus_running = 1;
10411 mutex_unlock(&pmus_lock);
10415 device_initcall(perf_event_sysfs_init);
10417 #ifdef CONFIG_CGROUP_PERF
10418 static struct cgroup_subsys_state *
10419 perf_cgroup_css_alloc(struct cgroup_subsys_state *parent_css)
10421 struct perf_cgroup *jc;
10423 jc = kzalloc(sizeof(*jc), GFP_KERNEL);
10425 return ERR_PTR(-ENOMEM);
10427 jc->info = alloc_percpu(struct perf_cgroup_info);
10430 return ERR_PTR(-ENOMEM);
10436 static void perf_cgroup_css_free(struct cgroup_subsys_state *css)
10438 struct perf_cgroup *jc = container_of(css, struct perf_cgroup, css);
10440 free_percpu(jc->info);
10444 static int __perf_cgroup_move(void *info)
10446 struct task_struct *task = info;
10448 perf_cgroup_switch(task, PERF_CGROUP_SWOUT | PERF_CGROUP_SWIN);
10453 static void perf_cgroup_attach(struct cgroup_taskset *tset)
10455 struct task_struct *task;
10456 struct cgroup_subsys_state *css;
10458 cgroup_taskset_for_each(task, css, tset)
10459 task_function_call(task, __perf_cgroup_move, task);
10462 struct cgroup_subsys perf_event_cgrp_subsys = {
10463 .css_alloc = perf_cgroup_css_alloc,
10464 .css_free = perf_cgroup_css_free,
10465 .attach = perf_cgroup_attach,
10467 #endif /* CONFIG_CGROUP_PERF */