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 * Check whether we should attempt to schedule an event group based on
1689 * PMU-specific filtering. An event group can consist of HW and SW events,
1690 * potentially with a SW leader, so we must check all the filters, to
1691 * determine whether a group is schedulable:
1693 static inline int pmu_filter_match(struct perf_event *event)
1695 struct perf_event *child;
1697 if (!__pmu_filter_match(event))
1700 list_for_each_entry(child, &event->sibling_list, group_entry) {
1701 if (!__pmu_filter_match(child))
1709 event_filter_match(struct perf_event *event)
1711 return (event->cpu == -1 || event->cpu == smp_processor_id())
1712 && perf_cgroup_match(event) && pmu_filter_match(event);
1716 event_sched_out(struct perf_event *event,
1717 struct perf_cpu_context *cpuctx,
1718 struct perf_event_context *ctx)
1720 u64 tstamp = perf_event_time(event);
1723 WARN_ON_ONCE(event->ctx != ctx);
1724 lockdep_assert_held(&ctx->lock);
1727 * An event which could not be activated because of
1728 * filter mismatch still needs to have its timings
1729 * maintained, otherwise bogus information is return
1730 * via read() for time_enabled, time_running:
1732 if (event->state == PERF_EVENT_STATE_INACTIVE
1733 && !event_filter_match(event)) {
1734 delta = tstamp - event->tstamp_stopped;
1735 event->tstamp_running += delta;
1736 event->tstamp_stopped = tstamp;
1739 if (event->state != PERF_EVENT_STATE_ACTIVE)
1742 perf_pmu_disable(event->pmu);
1744 event->tstamp_stopped = tstamp;
1745 event->pmu->del(event, 0);
1747 event->state = PERF_EVENT_STATE_INACTIVE;
1748 if (event->pending_disable) {
1749 event->pending_disable = 0;
1750 event->state = PERF_EVENT_STATE_OFF;
1753 if (!is_software_event(event))
1754 cpuctx->active_oncpu--;
1755 if (!--ctx->nr_active)
1756 perf_event_ctx_deactivate(ctx);
1757 if (event->attr.freq && event->attr.sample_freq)
1759 if (event->attr.exclusive || !cpuctx->active_oncpu)
1760 cpuctx->exclusive = 0;
1762 perf_pmu_enable(event->pmu);
1766 group_sched_out(struct perf_event *group_event,
1767 struct perf_cpu_context *cpuctx,
1768 struct perf_event_context *ctx)
1770 struct perf_event *event;
1771 int state = group_event->state;
1773 event_sched_out(group_event, cpuctx, ctx);
1776 * Schedule out siblings (if any):
1778 list_for_each_entry(event, &group_event->sibling_list, group_entry)
1779 event_sched_out(event, cpuctx, ctx);
1781 if (state == PERF_EVENT_STATE_ACTIVE && group_event->attr.exclusive)
1782 cpuctx->exclusive = 0;
1785 #define DETACH_GROUP 0x01UL
1788 * Cross CPU call to remove a performance event
1790 * We disable the event on the hardware level first. After that we
1791 * remove it from the context list.
1794 __perf_remove_from_context(struct perf_event *event,
1795 struct perf_cpu_context *cpuctx,
1796 struct perf_event_context *ctx,
1799 unsigned long flags = (unsigned long)info;
1801 event_sched_out(event, cpuctx, ctx);
1802 if (flags & DETACH_GROUP)
1803 perf_group_detach(event);
1804 list_del_event(event, ctx);
1806 if (!ctx->nr_events && ctx->is_active) {
1809 WARN_ON_ONCE(cpuctx->task_ctx != ctx);
1810 cpuctx->task_ctx = NULL;
1816 * Remove the event from a task's (or a CPU's) list of events.
1818 * If event->ctx is a cloned context, callers must make sure that
1819 * every task struct that event->ctx->task could possibly point to
1820 * remains valid. This is OK when called from perf_release since
1821 * that only calls us on the top-level context, which can't be a clone.
1822 * When called from perf_event_exit_task, it's OK because the
1823 * context has been detached from its task.
1825 static void perf_remove_from_context(struct perf_event *event, unsigned long flags)
1827 lockdep_assert_held(&event->ctx->mutex);
1829 event_function_call(event, __perf_remove_from_context, (void *)flags);
1833 * Cross CPU call to disable a performance event
1835 static void __perf_event_disable(struct perf_event *event,
1836 struct perf_cpu_context *cpuctx,
1837 struct perf_event_context *ctx,
1840 if (event->state < PERF_EVENT_STATE_INACTIVE)
1843 update_context_time(ctx);
1844 update_cgrp_time_from_event(event);
1845 update_group_times(event);
1846 if (event == event->group_leader)
1847 group_sched_out(event, cpuctx, ctx);
1849 event_sched_out(event, cpuctx, ctx);
1850 event->state = PERF_EVENT_STATE_OFF;
1856 * If event->ctx is a cloned context, callers must make sure that
1857 * every task struct that event->ctx->task could possibly point to
1858 * remains valid. This condition is satisifed when called through
1859 * perf_event_for_each_child or perf_event_for_each because they
1860 * hold the top-level event's child_mutex, so any descendant that
1861 * goes to exit will block in perf_event_exit_event().
1863 * When called from perf_pending_event it's OK because event->ctx
1864 * is the current context on this CPU and preemption is disabled,
1865 * hence we can't get into perf_event_task_sched_out for this context.
1867 static void _perf_event_disable(struct perf_event *event)
1869 struct perf_event_context *ctx = event->ctx;
1871 raw_spin_lock_irq(&ctx->lock);
1872 if (event->state <= PERF_EVENT_STATE_OFF) {
1873 raw_spin_unlock_irq(&ctx->lock);
1876 raw_spin_unlock_irq(&ctx->lock);
1878 event_function_call(event, __perf_event_disable, NULL);
1881 void perf_event_disable_local(struct perf_event *event)
1883 event_function_local(event, __perf_event_disable, NULL);
1887 * Strictly speaking kernel users cannot create groups and therefore this
1888 * interface does not need the perf_event_ctx_lock() magic.
1890 void perf_event_disable(struct perf_event *event)
1892 struct perf_event_context *ctx;
1894 ctx = perf_event_ctx_lock(event);
1895 _perf_event_disable(event);
1896 perf_event_ctx_unlock(event, ctx);
1898 EXPORT_SYMBOL_GPL(perf_event_disable);
1900 static void perf_set_shadow_time(struct perf_event *event,
1901 struct perf_event_context *ctx,
1905 * use the correct time source for the time snapshot
1907 * We could get by without this by leveraging the
1908 * fact that to get to this function, the caller
1909 * has most likely already called update_context_time()
1910 * and update_cgrp_time_xx() and thus both timestamp
1911 * are identical (or very close). Given that tstamp is,
1912 * already adjusted for cgroup, we could say that:
1913 * tstamp - ctx->timestamp
1915 * tstamp - cgrp->timestamp.
1917 * Then, in perf_output_read(), the calculation would
1918 * work with no changes because:
1919 * - event is guaranteed scheduled in
1920 * - no scheduled out in between
1921 * - thus the timestamp would be the same
1923 * But this is a bit hairy.
1925 * So instead, we have an explicit cgroup call to remain
1926 * within the time time source all along. We believe it
1927 * is cleaner and simpler to understand.
1929 if (is_cgroup_event(event))
1930 perf_cgroup_set_shadow_time(event, tstamp);
1932 event->shadow_ctx_time = tstamp - ctx->timestamp;
1935 #define MAX_INTERRUPTS (~0ULL)
1937 static void perf_log_throttle(struct perf_event *event, int enable);
1938 static void perf_log_itrace_start(struct perf_event *event);
1941 event_sched_in(struct perf_event *event,
1942 struct perf_cpu_context *cpuctx,
1943 struct perf_event_context *ctx)
1945 u64 tstamp = perf_event_time(event);
1948 lockdep_assert_held(&ctx->lock);
1950 if (event->state <= PERF_EVENT_STATE_OFF)
1953 WRITE_ONCE(event->oncpu, smp_processor_id());
1955 * Order event::oncpu write to happen before the ACTIVE state
1959 WRITE_ONCE(event->state, PERF_EVENT_STATE_ACTIVE);
1962 * Unthrottle events, since we scheduled we might have missed several
1963 * ticks already, also for a heavily scheduling task there is little
1964 * guarantee it'll get a tick in a timely manner.
1966 if (unlikely(event->hw.interrupts == MAX_INTERRUPTS)) {
1967 perf_log_throttle(event, 1);
1968 event->hw.interrupts = 0;
1972 * The new state must be visible before we turn it on in the hardware:
1976 perf_pmu_disable(event->pmu);
1978 perf_set_shadow_time(event, ctx, tstamp);
1980 perf_log_itrace_start(event);
1982 if (event->pmu->add(event, PERF_EF_START)) {
1983 event->state = PERF_EVENT_STATE_INACTIVE;
1989 event->tstamp_running += tstamp - event->tstamp_stopped;
1991 if (!is_software_event(event))
1992 cpuctx->active_oncpu++;
1993 if (!ctx->nr_active++)
1994 perf_event_ctx_activate(ctx);
1995 if (event->attr.freq && event->attr.sample_freq)
1998 if (event->attr.exclusive)
1999 cpuctx->exclusive = 1;
2002 perf_pmu_enable(event->pmu);
2008 group_sched_in(struct perf_event *group_event,
2009 struct perf_cpu_context *cpuctx,
2010 struct perf_event_context *ctx)
2012 struct perf_event *event, *partial_group = NULL;
2013 struct pmu *pmu = ctx->pmu;
2014 u64 now = ctx->time;
2015 bool simulate = false;
2017 if (group_event->state == PERF_EVENT_STATE_OFF)
2020 pmu->start_txn(pmu, PERF_PMU_TXN_ADD);
2022 if (event_sched_in(group_event, cpuctx, ctx)) {
2023 pmu->cancel_txn(pmu);
2024 perf_mux_hrtimer_restart(cpuctx);
2029 * Schedule in siblings as one group (if any):
2031 list_for_each_entry(event, &group_event->sibling_list, group_entry) {
2032 if (event_sched_in(event, cpuctx, ctx)) {
2033 partial_group = event;
2038 if (!pmu->commit_txn(pmu))
2043 * Groups can be scheduled in as one unit only, so undo any
2044 * partial group before returning:
2045 * The events up to the failed event are scheduled out normally,
2046 * tstamp_stopped will be updated.
2048 * The failed events and the remaining siblings need to have
2049 * their timings updated as if they had gone thru event_sched_in()
2050 * and event_sched_out(). This is required to get consistent timings
2051 * across the group. This also takes care of the case where the group
2052 * could never be scheduled by ensuring tstamp_stopped is set to mark
2053 * the time the event was actually stopped, such that time delta
2054 * calculation in update_event_times() is correct.
2056 list_for_each_entry(event, &group_event->sibling_list, group_entry) {
2057 if (event == partial_group)
2061 event->tstamp_running += now - event->tstamp_stopped;
2062 event->tstamp_stopped = now;
2064 event_sched_out(event, cpuctx, ctx);
2067 event_sched_out(group_event, cpuctx, ctx);
2069 pmu->cancel_txn(pmu);
2071 perf_mux_hrtimer_restart(cpuctx);
2077 * Work out whether we can put this event group on the CPU now.
2079 static int group_can_go_on(struct perf_event *event,
2080 struct perf_cpu_context *cpuctx,
2084 * Groups consisting entirely of software events can always go on.
2086 if (event->group_flags & PERF_GROUP_SOFTWARE)
2089 * If an exclusive group is already on, no other hardware
2092 if (cpuctx->exclusive)
2095 * If this group is exclusive and there are already
2096 * events on the CPU, it can't go on.
2098 if (event->attr.exclusive && cpuctx->active_oncpu)
2101 * Otherwise, try to add it if all previous groups were able
2107 static void add_event_to_ctx(struct perf_event *event,
2108 struct perf_event_context *ctx)
2110 u64 tstamp = perf_event_time(event);
2112 list_add_event(event, ctx);
2113 perf_group_attach(event);
2114 event->tstamp_enabled = tstamp;
2115 event->tstamp_running = tstamp;
2116 event->tstamp_stopped = tstamp;
2119 static void ctx_sched_out(struct perf_event_context *ctx,
2120 struct perf_cpu_context *cpuctx,
2121 enum event_type_t event_type);
2123 ctx_sched_in(struct perf_event_context *ctx,
2124 struct perf_cpu_context *cpuctx,
2125 enum event_type_t event_type,
2126 struct task_struct *task);
2128 static void task_ctx_sched_out(struct perf_cpu_context *cpuctx,
2129 struct perf_event_context *ctx)
2131 if (!cpuctx->task_ctx)
2134 if (WARN_ON_ONCE(ctx != cpuctx->task_ctx))
2137 ctx_sched_out(ctx, cpuctx, EVENT_ALL);
2140 static void perf_event_sched_in(struct perf_cpu_context *cpuctx,
2141 struct perf_event_context *ctx,
2142 struct task_struct *task)
2144 cpu_ctx_sched_in(cpuctx, EVENT_PINNED, task);
2146 ctx_sched_in(ctx, cpuctx, EVENT_PINNED, task);
2147 cpu_ctx_sched_in(cpuctx, EVENT_FLEXIBLE, task);
2149 ctx_sched_in(ctx, cpuctx, EVENT_FLEXIBLE, task);
2152 static void ctx_resched(struct perf_cpu_context *cpuctx,
2153 struct perf_event_context *task_ctx)
2155 perf_pmu_disable(cpuctx->ctx.pmu);
2157 task_ctx_sched_out(cpuctx, task_ctx);
2158 cpu_ctx_sched_out(cpuctx, EVENT_ALL);
2159 perf_event_sched_in(cpuctx, task_ctx, current);
2160 perf_pmu_enable(cpuctx->ctx.pmu);
2164 * Cross CPU call to install and enable a performance event
2166 * Very similar to remote_function() + event_function() but cannot assume that
2167 * things like ctx->is_active and cpuctx->task_ctx are set.
2169 static int __perf_install_in_context(void *info)
2171 struct perf_event *event = info;
2172 struct perf_event_context *ctx = event->ctx;
2173 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
2174 struct perf_event_context *task_ctx = cpuctx->task_ctx;
2175 bool activate = true;
2178 raw_spin_lock(&cpuctx->ctx.lock);
2180 raw_spin_lock(&ctx->lock);
2183 /* If we're on the wrong CPU, try again */
2184 if (task_cpu(ctx->task) != smp_processor_id()) {
2190 * If we're on the right CPU, see if the task we target is
2191 * current, if not we don't have to activate the ctx, a future
2192 * context switch will do that for us.
2194 if (ctx->task != current)
2197 WARN_ON_ONCE(cpuctx->task_ctx && cpuctx->task_ctx != ctx);
2199 } else if (task_ctx) {
2200 raw_spin_lock(&task_ctx->lock);
2204 ctx_sched_out(ctx, cpuctx, EVENT_TIME);
2205 add_event_to_ctx(event, ctx);
2206 ctx_resched(cpuctx, task_ctx);
2208 add_event_to_ctx(event, ctx);
2212 perf_ctx_unlock(cpuctx, task_ctx);
2218 * Attach a performance event to a context.
2220 * Very similar to event_function_call, see comment there.
2223 perf_install_in_context(struct perf_event_context *ctx,
2224 struct perf_event *event,
2227 struct task_struct *task = READ_ONCE(ctx->task);
2229 lockdep_assert_held(&ctx->mutex);
2232 if (event->cpu != -1)
2236 cpu_function_call(cpu, __perf_install_in_context, event);
2241 * Should not happen, we validate the ctx is still alive before calling.
2243 if (WARN_ON_ONCE(task == TASK_TOMBSTONE))
2247 * Installing events is tricky because we cannot rely on ctx->is_active
2248 * to be set in case this is the nr_events 0 -> 1 transition.
2252 * Cannot use task_function_call() because we need to run on the task's
2253 * CPU regardless of whether its current or not.
2255 if (!cpu_function_call(task_cpu(task), __perf_install_in_context, event))
2258 raw_spin_lock_irq(&ctx->lock);
2260 if (WARN_ON_ONCE(task == TASK_TOMBSTONE)) {
2262 * Cannot happen because we already checked above (which also
2263 * cannot happen), and we hold ctx->mutex, which serializes us
2264 * against perf_event_exit_task_context().
2266 raw_spin_unlock_irq(&ctx->lock);
2269 raw_spin_unlock_irq(&ctx->lock);
2271 * Since !ctx->is_active doesn't mean anything, we must IPI
2278 * Put a event into inactive state and update time fields.
2279 * Enabling the leader of a group effectively enables all
2280 * the group members that aren't explicitly disabled, so we
2281 * have to update their ->tstamp_enabled also.
2282 * Note: this works for group members as well as group leaders
2283 * since the non-leader members' sibling_lists will be empty.
2285 static void __perf_event_mark_enabled(struct perf_event *event)
2287 struct perf_event *sub;
2288 u64 tstamp = perf_event_time(event);
2290 event->state = PERF_EVENT_STATE_INACTIVE;
2291 event->tstamp_enabled = tstamp - event->total_time_enabled;
2292 list_for_each_entry(sub, &event->sibling_list, group_entry) {
2293 if (sub->state >= PERF_EVENT_STATE_INACTIVE)
2294 sub->tstamp_enabled = tstamp - sub->total_time_enabled;
2299 * Cross CPU call to enable a performance event
2301 static void __perf_event_enable(struct perf_event *event,
2302 struct perf_cpu_context *cpuctx,
2303 struct perf_event_context *ctx,
2306 struct perf_event *leader = event->group_leader;
2307 struct perf_event_context *task_ctx;
2309 if (event->state >= PERF_EVENT_STATE_INACTIVE ||
2310 event->state <= PERF_EVENT_STATE_ERROR)
2314 ctx_sched_out(ctx, cpuctx, EVENT_TIME);
2316 __perf_event_mark_enabled(event);
2318 if (!ctx->is_active)
2321 if (!event_filter_match(event)) {
2322 if (is_cgroup_event(event))
2323 perf_cgroup_defer_enabled(event);
2324 ctx_sched_in(ctx, cpuctx, EVENT_TIME, current);
2329 * If the event is in a group and isn't the group leader,
2330 * then don't put it on unless the group is on.
2332 if (leader != event && leader->state != PERF_EVENT_STATE_ACTIVE) {
2333 ctx_sched_in(ctx, cpuctx, EVENT_TIME, current);
2337 task_ctx = cpuctx->task_ctx;
2339 WARN_ON_ONCE(task_ctx != ctx);
2341 ctx_resched(cpuctx, task_ctx);
2347 * If event->ctx is a cloned context, callers must make sure that
2348 * every task struct that event->ctx->task could possibly point to
2349 * remains valid. This condition is satisfied when called through
2350 * perf_event_for_each_child or perf_event_for_each as described
2351 * for perf_event_disable.
2353 static void _perf_event_enable(struct perf_event *event)
2355 struct perf_event_context *ctx = event->ctx;
2357 raw_spin_lock_irq(&ctx->lock);
2358 if (event->state >= PERF_EVENT_STATE_INACTIVE ||
2359 event->state < PERF_EVENT_STATE_ERROR) {
2360 raw_spin_unlock_irq(&ctx->lock);
2365 * If the event is in error state, clear that first.
2367 * That way, if we see the event in error state below, we know that it
2368 * has gone back into error state, as distinct from the task having
2369 * been scheduled away before the cross-call arrived.
2371 if (event->state == PERF_EVENT_STATE_ERROR)
2372 event->state = PERF_EVENT_STATE_OFF;
2373 raw_spin_unlock_irq(&ctx->lock);
2375 event_function_call(event, __perf_event_enable, NULL);
2379 * See perf_event_disable();
2381 void perf_event_enable(struct perf_event *event)
2383 struct perf_event_context *ctx;
2385 ctx = perf_event_ctx_lock(event);
2386 _perf_event_enable(event);
2387 perf_event_ctx_unlock(event, ctx);
2389 EXPORT_SYMBOL_GPL(perf_event_enable);
2391 struct stop_event_data {
2392 struct perf_event *event;
2393 unsigned int restart;
2396 static int __perf_event_stop(void *info)
2398 struct stop_event_data *sd = info;
2399 struct perf_event *event = sd->event;
2401 /* if it's already INACTIVE, do nothing */
2402 if (READ_ONCE(event->state) != PERF_EVENT_STATE_ACTIVE)
2405 /* matches smp_wmb() in event_sched_in() */
2409 * There is a window with interrupts enabled before we get here,
2410 * so we need to check again lest we try to stop another CPU's event.
2412 if (READ_ONCE(event->oncpu) != smp_processor_id())
2415 event->pmu->stop(event, PERF_EF_UPDATE);
2418 * May race with the actual stop (through perf_pmu_output_stop()),
2419 * but it is only used for events with AUX ring buffer, and such
2420 * events will refuse to restart because of rb::aux_mmap_count==0,
2421 * see comments in perf_aux_output_begin().
2423 * Since this is happening on a event-local CPU, no trace is lost
2427 event->pmu->start(event, PERF_EF_START);
2432 static int perf_event_restart(struct perf_event *event)
2434 struct stop_event_data sd = {
2441 if (READ_ONCE(event->state) != PERF_EVENT_STATE_ACTIVE)
2444 /* matches smp_wmb() in event_sched_in() */
2448 * We only want to restart ACTIVE events, so if the event goes
2449 * inactive here (event->oncpu==-1), there's nothing more to do;
2450 * fall through with ret==-ENXIO.
2452 ret = cpu_function_call(READ_ONCE(event->oncpu),
2453 __perf_event_stop, &sd);
2454 } while (ret == -EAGAIN);
2460 * In order to contain the amount of racy and tricky in the address filter
2461 * configuration management, it is a two part process:
2463 * (p1) when userspace mappings change as a result of (1) or (2) or (3) below,
2464 * we update the addresses of corresponding vmas in
2465 * event::addr_filters_offs array and bump the event::addr_filters_gen;
2466 * (p2) when an event is scheduled in (pmu::add), it calls
2467 * perf_event_addr_filters_sync() which calls pmu::addr_filters_sync()
2468 * if the generation has changed since the previous call.
2470 * If (p1) happens while the event is active, we restart it to force (p2).
2472 * (1) perf_addr_filters_apply(): adjusting filters' offsets based on
2473 * pre-existing mappings, called once when new filters arrive via SET_FILTER
2475 * (2) perf_addr_filters_adjust(): adjusting filters' offsets based on newly
2476 * registered mapping, called for every new mmap(), with mm::mmap_sem down
2478 * (3) perf_event_addr_filters_exec(): clearing filters' offsets in the process
2481 void perf_event_addr_filters_sync(struct perf_event *event)
2483 struct perf_addr_filters_head *ifh = perf_event_addr_filters(event);
2485 if (!has_addr_filter(event))
2488 raw_spin_lock(&ifh->lock);
2489 if (event->addr_filters_gen != event->hw.addr_filters_gen) {
2490 event->pmu->addr_filters_sync(event);
2491 event->hw.addr_filters_gen = event->addr_filters_gen;
2493 raw_spin_unlock(&ifh->lock);
2495 EXPORT_SYMBOL_GPL(perf_event_addr_filters_sync);
2497 static int _perf_event_refresh(struct perf_event *event, int refresh)
2500 * not supported on inherited events
2502 if (event->attr.inherit || !is_sampling_event(event))
2505 atomic_add(refresh, &event->event_limit);
2506 _perf_event_enable(event);
2512 * See perf_event_disable()
2514 int perf_event_refresh(struct perf_event *event, int refresh)
2516 struct perf_event_context *ctx;
2519 ctx = perf_event_ctx_lock(event);
2520 ret = _perf_event_refresh(event, refresh);
2521 perf_event_ctx_unlock(event, ctx);
2525 EXPORT_SYMBOL_GPL(perf_event_refresh);
2527 static void ctx_sched_out(struct perf_event_context *ctx,
2528 struct perf_cpu_context *cpuctx,
2529 enum event_type_t event_type)
2531 int is_active = ctx->is_active;
2532 struct perf_event *event;
2534 lockdep_assert_held(&ctx->lock);
2536 if (likely(!ctx->nr_events)) {
2538 * See __perf_remove_from_context().
2540 WARN_ON_ONCE(ctx->is_active);
2542 WARN_ON_ONCE(cpuctx->task_ctx);
2546 ctx->is_active &= ~event_type;
2547 if (!(ctx->is_active & EVENT_ALL))
2551 WARN_ON_ONCE(cpuctx->task_ctx != ctx);
2552 if (!ctx->is_active)
2553 cpuctx->task_ctx = NULL;
2557 * Always update time if it was set; not only when it changes.
2558 * Otherwise we can 'forget' to update time for any but the last
2559 * context we sched out. For example:
2561 * ctx_sched_out(.event_type = EVENT_FLEXIBLE)
2562 * ctx_sched_out(.event_type = EVENT_PINNED)
2564 * would only update time for the pinned events.
2566 if (is_active & EVENT_TIME) {
2567 /* update (and stop) ctx time */
2568 update_context_time(ctx);
2569 update_cgrp_time_from_cpuctx(cpuctx);
2572 is_active ^= ctx->is_active; /* changed bits */
2574 if (!ctx->nr_active || !(is_active & EVENT_ALL))
2577 perf_pmu_disable(ctx->pmu);
2578 if (is_active & EVENT_PINNED) {
2579 list_for_each_entry(event, &ctx->pinned_groups, group_entry)
2580 group_sched_out(event, cpuctx, ctx);
2583 if (is_active & EVENT_FLEXIBLE) {
2584 list_for_each_entry(event, &ctx->flexible_groups, group_entry)
2585 group_sched_out(event, cpuctx, ctx);
2587 perf_pmu_enable(ctx->pmu);
2591 * Test whether two contexts are equivalent, i.e. whether they have both been
2592 * cloned from the same version of the same context.
2594 * Equivalence is measured using a generation number in the context that is
2595 * incremented on each modification to it; see unclone_ctx(), list_add_event()
2596 * and list_del_event().
2598 static int context_equiv(struct perf_event_context *ctx1,
2599 struct perf_event_context *ctx2)
2601 lockdep_assert_held(&ctx1->lock);
2602 lockdep_assert_held(&ctx2->lock);
2604 /* Pinning disables the swap optimization */
2605 if (ctx1->pin_count || ctx2->pin_count)
2608 /* If ctx1 is the parent of ctx2 */
2609 if (ctx1 == ctx2->parent_ctx && ctx1->generation == ctx2->parent_gen)
2612 /* If ctx2 is the parent of ctx1 */
2613 if (ctx1->parent_ctx == ctx2 && ctx1->parent_gen == ctx2->generation)
2617 * If ctx1 and ctx2 have the same parent; we flatten the parent
2618 * hierarchy, see perf_event_init_context().
2620 if (ctx1->parent_ctx && ctx1->parent_ctx == ctx2->parent_ctx &&
2621 ctx1->parent_gen == ctx2->parent_gen)
2628 static void __perf_event_sync_stat(struct perf_event *event,
2629 struct perf_event *next_event)
2633 if (!event->attr.inherit_stat)
2637 * Update the event value, we cannot use perf_event_read()
2638 * because we're in the middle of a context switch and have IRQs
2639 * disabled, which upsets smp_call_function_single(), however
2640 * we know the event must be on the current CPU, therefore we
2641 * don't need to use it.
2643 switch (event->state) {
2644 case PERF_EVENT_STATE_ACTIVE:
2645 event->pmu->read(event);
2648 case PERF_EVENT_STATE_INACTIVE:
2649 update_event_times(event);
2657 * In order to keep per-task stats reliable we need to flip the event
2658 * values when we flip the contexts.
2660 value = local64_read(&next_event->count);
2661 value = local64_xchg(&event->count, value);
2662 local64_set(&next_event->count, value);
2664 swap(event->total_time_enabled, next_event->total_time_enabled);
2665 swap(event->total_time_running, next_event->total_time_running);
2668 * Since we swizzled the values, update the user visible data too.
2670 perf_event_update_userpage(event);
2671 perf_event_update_userpage(next_event);
2674 static void perf_event_sync_stat(struct perf_event_context *ctx,
2675 struct perf_event_context *next_ctx)
2677 struct perf_event *event, *next_event;
2682 update_context_time(ctx);
2684 event = list_first_entry(&ctx->event_list,
2685 struct perf_event, event_entry);
2687 next_event = list_first_entry(&next_ctx->event_list,
2688 struct perf_event, event_entry);
2690 while (&event->event_entry != &ctx->event_list &&
2691 &next_event->event_entry != &next_ctx->event_list) {
2693 __perf_event_sync_stat(event, next_event);
2695 event = list_next_entry(event, event_entry);
2696 next_event = list_next_entry(next_event, event_entry);
2700 static void perf_event_context_sched_out(struct task_struct *task, int ctxn,
2701 struct task_struct *next)
2703 struct perf_event_context *ctx = task->perf_event_ctxp[ctxn];
2704 struct perf_event_context *next_ctx;
2705 struct perf_event_context *parent, *next_parent;
2706 struct perf_cpu_context *cpuctx;
2712 cpuctx = __get_cpu_context(ctx);
2713 if (!cpuctx->task_ctx)
2717 next_ctx = next->perf_event_ctxp[ctxn];
2721 parent = rcu_dereference(ctx->parent_ctx);
2722 next_parent = rcu_dereference(next_ctx->parent_ctx);
2724 /* If neither context have a parent context; they cannot be clones. */
2725 if (!parent && !next_parent)
2728 if (next_parent == ctx || next_ctx == parent || next_parent == parent) {
2730 * Looks like the two contexts are clones, so we might be
2731 * able to optimize the context switch. We lock both
2732 * contexts and check that they are clones under the
2733 * lock (including re-checking that neither has been
2734 * uncloned in the meantime). It doesn't matter which
2735 * order we take the locks because no other cpu could
2736 * be trying to lock both of these tasks.
2738 raw_spin_lock(&ctx->lock);
2739 raw_spin_lock_nested(&next_ctx->lock, SINGLE_DEPTH_NESTING);
2740 if (context_equiv(ctx, next_ctx)) {
2741 WRITE_ONCE(ctx->task, next);
2742 WRITE_ONCE(next_ctx->task, task);
2744 swap(ctx->task_ctx_data, next_ctx->task_ctx_data);
2747 * RCU_INIT_POINTER here is safe because we've not
2748 * modified the ctx and the above modification of
2749 * ctx->task and ctx->task_ctx_data are immaterial
2750 * since those values are always verified under
2751 * ctx->lock which we're now holding.
2753 RCU_INIT_POINTER(task->perf_event_ctxp[ctxn], next_ctx);
2754 RCU_INIT_POINTER(next->perf_event_ctxp[ctxn], ctx);
2758 perf_event_sync_stat(ctx, next_ctx);
2760 raw_spin_unlock(&next_ctx->lock);
2761 raw_spin_unlock(&ctx->lock);
2767 raw_spin_lock(&ctx->lock);
2768 task_ctx_sched_out(cpuctx, ctx);
2769 raw_spin_unlock(&ctx->lock);
2773 void perf_sched_cb_dec(struct pmu *pmu)
2775 this_cpu_dec(perf_sched_cb_usages);
2778 void perf_sched_cb_inc(struct pmu *pmu)
2780 this_cpu_inc(perf_sched_cb_usages);
2784 * This function provides the context switch callback to the lower code
2785 * layer. It is invoked ONLY when the context switch callback is enabled.
2787 static void perf_pmu_sched_task(struct task_struct *prev,
2788 struct task_struct *next,
2791 struct perf_cpu_context *cpuctx;
2793 unsigned long flags;
2798 local_irq_save(flags);
2802 list_for_each_entry_rcu(pmu, &pmus, entry) {
2803 if (pmu->sched_task) {
2804 cpuctx = this_cpu_ptr(pmu->pmu_cpu_context);
2806 perf_ctx_lock(cpuctx, cpuctx->task_ctx);
2808 perf_pmu_disable(pmu);
2810 pmu->sched_task(cpuctx->task_ctx, sched_in);
2812 perf_pmu_enable(pmu);
2814 perf_ctx_unlock(cpuctx, cpuctx->task_ctx);
2820 local_irq_restore(flags);
2823 static void perf_event_switch(struct task_struct *task,
2824 struct task_struct *next_prev, bool sched_in);
2826 #define for_each_task_context_nr(ctxn) \
2827 for ((ctxn) = 0; (ctxn) < perf_nr_task_contexts; (ctxn)++)
2830 * Called from scheduler to remove the events of the current task,
2831 * with interrupts disabled.
2833 * We stop each event and update the event value in event->count.
2835 * This does not protect us against NMI, but disable()
2836 * sets the disabled bit in the control field of event _before_
2837 * accessing the event control register. If a NMI hits, then it will
2838 * not restart the event.
2840 void __perf_event_task_sched_out(struct task_struct *task,
2841 struct task_struct *next)
2845 if (__this_cpu_read(perf_sched_cb_usages))
2846 perf_pmu_sched_task(task, next, false);
2848 if (atomic_read(&nr_switch_events))
2849 perf_event_switch(task, next, false);
2851 for_each_task_context_nr(ctxn)
2852 perf_event_context_sched_out(task, ctxn, next);
2855 * if cgroup events exist on this CPU, then we need
2856 * to check if we have to switch out PMU state.
2857 * cgroup event are system-wide mode only
2859 if (atomic_read(this_cpu_ptr(&perf_cgroup_events)))
2860 perf_cgroup_sched_out(task, next);
2864 * Called with IRQs disabled
2866 static void cpu_ctx_sched_out(struct perf_cpu_context *cpuctx,
2867 enum event_type_t event_type)
2869 ctx_sched_out(&cpuctx->ctx, cpuctx, event_type);
2873 ctx_pinned_sched_in(struct perf_event_context *ctx,
2874 struct perf_cpu_context *cpuctx)
2876 struct perf_event *event;
2878 list_for_each_entry(event, &ctx->pinned_groups, group_entry) {
2879 if (event->state <= PERF_EVENT_STATE_OFF)
2881 if (!event_filter_match(event))
2884 /* may need to reset tstamp_enabled */
2885 if (is_cgroup_event(event))
2886 perf_cgroup_mark_enabled(event, ctx);
2888 if (group_can_go_on(event, cpuctx, 1))
2889 group_sched_in(event, cpuctx, ctx);
2892 * If this pinned group hasn't been scheduled,
2893 * put it in error state.
2895 if (event->state == PERF_EVENT_STATE_INACTIVE) {
2896 update_group_times(event);
2897 event->state = PERF_EVENT_STATE_ERROR;
2903 ctx_flexible_sched_in(struct perf_event_context *ctx,
2904 struct perf_cpu_context *cpuctx)
2906 struct perf_event *event;
2909 list_for_each_entry(event, &ctx->flexible_groups, group_entry) {
2910 /* Ignore events in OFF or ERROR state */
2911 if (event->state <= PERF_EVENT_STATE_OFF)
2914 * Listen to the 'cpu' scheduling filter constraint
2917 if (!event_filter_match(event))
2920 /* may need to reset tstamp_enabled */
2921 if (is_cgroup_event(event))
2922 perf_cgroup_mark_enabled(event, ctx);
2924 if (group_can_go_on(event, cpuctx, can_add_hw)) {
2925 if (group_sched_in(event, cpuctx, ctx))
2932 ctx_sched_in(struct perf_event_context *ctx,
2933 struct perf_cpu_context *cpuctx,
2934 enum event_type_t event_type,
2935 struct task_struct *task)
2937 int is_active = ctx->is_active;
2940 lockdep_assert_held(&ctx->lock);
2942 if (likely(!ctx->nr_events))
2945 ctx->is_active |= (event_type | EVENT_TIME);
2948 cpuctx->task_ctx = ctx;
2950 WARN_ON_ONCE(cpuctx->task_ctx != ctx);
2953 is_active ^= ctx->is_active; /* changed bits */
2955 if (is_active & EVENT_TIME) {
2956 /* start ctx time */
2958 ctx->timestamp = now;
2959 perf_cgroup_set_timestamp(task, ctx);
2963 * First go through the list and put on any pinned groups
2964 * in order to give them the best chance of going on.
2966 if (is_active & EVENT_PINNED)
2967 ctx_pinned_sched_in(ctx, cpuctx);
2969 /* Then walk through the lower prio flexible groups */
2970 if (is_active & EVENT_FLEXIBLE)
2971 ctx_flexible_sched_in(ctx, cpuctx);
2974 static void cpu_ctx_sched_in(struct perf_cpu_context *cpuctx,
2975 enum event_type_t event_type,
2976 struct task_struct *task)
2978 struct perf_event_context *ctx = &cpuctx->ctx;
2980 ctx_sched_in(ctx, cpuctx, event_type, task);
2983 static void perf_event_context_sched_in(struct perf_event_context *ctx,
2984 struct task_struct *task)
2986 struct perf_cpu_context *cpuctx;
2988 cpuctx = __get_cpu_context(ctx);
2989 if (cpuctx->task_ctx == ctx)
2992 perf_ctx_lock(cpuctx, ctx);
2993 perf_pmu_disable(ctx->pmu);
2995 * We want to keep the following priority order:
2996 * cpu pinned (that don't need to move), task pinned,
2997 * cpu flexible, task flexible.
2999 cpu_ctx_sched_out(cpuctx, EVENT_FLEXIBLE);
3000 perf_event_sched_in(cpuctx, ctx, task);
3001 perf_pmu_enable(ctx->pmu);
3002 perf_ctx_unlock(cpuctx, ctx);
3006 * Called from scheduler to add the events of the current task
3007 * with interrupts disabled.
3009 * We restore the event value and then enable it.
3011 * This does not protect us against NMI, but enable()
3012 * sets the enabled bit in the control field of event _before_
3013 * accessing the event control register. If a NMI hits, then it will
3014 * keep the event running.
3016 void __perf_event_task_sched_in(struct task_struct *prev,
3017 struct task_struct *task)
3019 struct perf_event_context *ctx;
3023 * If cgroup events exist on this CPU, then we need to check if we have
3024 * to switch in PMU state; cgroup event are system-wide mode only.
3026 * Since cgroup events are CPU events, we must schedule these in before
3027 * we schedule in the task events.
3029 if (atomic_read(this_cpu_ptr(&perf_cgroup_events)))
3030 perf_cgroup_sched_in(prev, task);
3032 for_each_task_context_nr(ctxn) {
3033 ctx = task->perf_event_ctxp[ctxn];
3037 perf_event_context_sched_in(ctx, task);
3040 if (atomic_read(&nr_switch_events))
3041 perf_event_switch(task, prev, true);
3043 if (__this_cpu_read(perf_sched_cb_usages))
3044 perf_pmu_sched_task(prev, task, true);
3047 static u64 perf_calculate_period(struct perf_event *event, u64 nsec, u64 count)
3049 u64 frequency = event->attr.sample_freq;
3050 u64 sec = NSEC_PER_SEC;
3051 u64 divisor, dividend;
3053 int count_fls, nsec_fls, frequency_fls, sec_fls;
3055 count_fls = fls64(count);
3056 nsec_fls = fls64(nsec);
3057 frequency_fls = fls64(frequency);
3061 * We got @count in @nsec, with a target of sample_freq HZ
3062 * the target period becomes:
3065 * period = -------------------
3066 * @nsec * sample_freq
3071 * Reduce accuracy by one bit such that @a and @b converge
3072 * to a similar magnitude.
3074 #define REDUCE_FLS(a, b) \
3076 if (a##_fls > b##_fls) { \
3086 * Reduce accuracy until either term fits in a u64, then proceed with
3087 * the other, so that finally we can do a u64/u64 division.
3089 while (count_fls + sec_fls > 64 && nsec_fls + frequency_fls > 64) {
3090 REDUCE_FLS(nsec, frequency);
3091 REDUCE_FLS(sec, count);
3094 if (count_fls + sec_fls > 64) {
3095 divisor = nsec * frequency;
3097 while (count_fls + sec_fls > 64) {
3098 REDUCE_FLS(count, sec);
3102 dividend = count * sec;
3104 dividend = count * sec;
3106 while (nsec_fls + frequency_fls > 64) {
3107 REDUCE_FLS(nsec, frequency);
3111 divisor = nsec * frequency;
3117 return div64_u64(dividend, divisor);
3120 static DEFINE_PER_CPU(int, perf_throttled_count);
3121 static DEFINE_PER_CPU(u64, perf_throttled_seq);
3123 static void perf_adjust_period(struct perf_event *event, u64 nsec, u64 count, bool disable)
3125 struct hw_perf_event *hwc = &event->hw;
3126 s64 period, sample_period;
3129 period = perf_calculate_period(event, nsec, count);
3131 delta = (s64)(period - hwc->sample_period);
3132 delta = (delta + 7) / 8; /* low pass filter */
3134 sample_period = hwc->sample_period + delta;
3139 hwc->sample_period = sample_period;
3141 if (local64_read(&hwc->period_left) > 8*sample_period) {
3143 event->pmu->stop(event, PERF_EF_UPDATE);
3145 local64_set(&hwc->period_left, 0);
3148 event->pmu->start(event, PERF_EF_RELOAD);
3153 * combine freq adjustment with unthrottling to avoid two passes over the
3154 * events. At the same time, make sure, having freq events does not change
3155 * the rate of unthrottling as that would introduce bias.
3157 static void perf_adjust_freq_unthr_context(struct perf_event_context *ctx,
3160 struct perf_event *event;
3161 struct hw_perf_event *hwc;
3162 u64 now, period = TICK_NSEC;
3166 * only need to iterate over all events iff:
3167 * - context have events in frequency mode (needs freq adjust)
3168 * - there are events to unthrottle on this cpu
3170 if (!(ctx->nr_freq || needs_unthr))
3173 raw_spin_lock(&ctx->lock);
3174 perf_pmu_disable(ctx->pmu);
3176 list_for_each_entry_rcu(event, &ctx->event_list, event_entry) {
3177 if (event->state != PERF_EVENT_STATE_ACTIVE)
3180 if (!event_filter_match(event))
3183 perf_pmu_disable(event->pmu);
3187 if (hwc->interrupts == MAX_INTERRUPTS) {
3188 hwc->interrupts = 0;
3189 perf_log_throttle(event, 1);
3190 event->pmu->start(event, 0);
3193 if (!event->attr.freq || !event->attr.sample_freq)
3197 * stop the event and update event->count
3199 event->pmu->stop(event, PERF_EF_UPDATE);
3201 now = local64_read(&event->count);
3202 delta = now - hwc->freq_count_stamp;
3203 hwc->freq_count_stamp = now;
3207 * reload only if value has changed
3208 * we have stopped the event so tell that
3209 * to perf_adjust_period() to avoid stopping it
3213 perf_adjust_period(event, period, delta, false);
3215 event->pmu->start(event, delta > 0 ? PERF_EF_RELOAD : 0);
3217 perf_pmu_enable(event->pmu);
3220 perf_pmu_enable(ctx->pmu);
3221 raw_spin_unlock(&ctx->lock);
3225 * Round-robin a context's events:
3227 static void rotate_ctx(struct perf_event_context *ctx)
3230 * Rotate the first entry last of non-pinned groups. Rotation might be
3231 * disabled by the inheritance code.
3233 if (!ctx->rotate_disable)
3234 list_rotate_left(&ctx->flexible_groups);
3237 static int perf_rotate_context(struct perf_cpu_context *cpuctx)
3239 struct perf_event_context *ctx = NULL;
3242 if (cpuctx->ctx.nr_events) {
3243 if (cpuctx->ctx.nr_events != cpuctx->ctx.nr_active)
3247 ctx = cpuctx->task_ctx;
3248 if (ctx && ctx->nr_events) {
3249 if (ctx->nr_events != ctx->nr_active)
3256 perf_ctx_lock(cpuctx, cpuctx->task_ctx);
3257 perf_pmu_disable(cpuctx->ctx.pmu);
3259 cpu_ctx_sched_out(cpuctx, EVENT_FLEXIBLE);
3261 ctx_sched_out(ctx, cpuctx, EVENT_FLEXIBLE);
3263 rotate_ctx(&cpuctx->ctx);
3267 perf_event_sched_in(cpuctx, ctx, current);
3269 perf_pmu_enable(cpuctx->ctx.pmu);
3270 perf_ctx_unlock(cpuctx, cpuctx->task_ctx);
3276 void perf_event_task_tick(void)
3278 struct list_head *head = this_cpu_ptr(&active_ctx_list);
3279 struct perf_event_context *ctx, *tmp;
3282 WARN_ON(!irqs_disabled());
3284 __this_cpu_inc(perf_throttled_seq);
3285 throttled = __this_cpu_xchg(perf_throttled_count, 0);
3286 tick_dep_clear_cpu(smp_processor_id(), TICK_DEP_BIT_PERF_EVENTS);
3288 list_for_each_entry_safe(ctx, tmp, head, active_ctx_list)
3289 perf_adjust_freq_unthr_context(ctx, throttled);
3292 static int event_enable_on_exec(struct perf_event *event,
3293 struct perf_event_context *ctx)
3295 if (!event->attr.enable_on_exec)
3298 event->attr.enable_on_exec = 0;
3299 if (event->state >= PERF_EVENT_STATE_INACTIVE)
3302 __perf_event_mark_enabled(event);
3308 * Enable all of a task's events that have been marked enable-on-exec.
3309 * This expects task == current.
3311 static void perf_event_enable_on_exec(int ctxn)
3313 struct perf_event_context *ctx, *clone_ctx = NULL;
3314 struct perf_cpu_context *cpuctx;
3315 struct perf_event *event;
3316 unsigned long flags;
3319 local_irq_save(flags);
3320 ctx = current->perf_event_ctxp[ctxn];
3321 if (!ctx || !ctx->nr_events)
3324 cpuctx = __get_cpu_context(ctx);
3325 perf_ctx_lock(cpuctx, ctx);
3326 ctx_sched_out(ctx, cpuctx, EVENT_TIME);
3327 list_for_each_entry(event, &ctx->event_list, event_entry)
3328 enabled |= event_enable_on_exec(event, ctx);
3331 * Unclone and reschedule this context if we enabled any event.
3334 clone_ctx = unclone_ctx(ctx);
3335 ctx_resched(cpuctx, ctx);
3337 perf_ctx_unlock(cpuctx, ctx);
3340 local_irq_restore(flags);
3346 struct perf_read_data {
3347 struct perf_event *event;
3353 * Cross CPU call to read the hardware event
3355 static void __perf_event_read(void *info)
3357 struct perf_read_data *data = info;
3358 struct perf_event *sub, *event = data->event;
3359 struct perf_event_context *ctx = event->ctx;
3360 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
3361 struct pmu *pmu = event->pmu;
3364 * If this is a task context, we need to check whether it is
3365 * the current task context of this cpu. If not it has been
3366 * scheduled out before the smp call arrived. In that case
3367 * event->count would have been updated to a recent sample
3368 * when the event was scheduled out.
3370 if (ctx->task && cpuctx->task_ctx != ctx)
3373 raw_spin_lock(&ctx->lock);
3374 if (ctx->is_active) {
3375 update_context_time(ctx);
3376 update_cgrp_time_from_event(event);
3379 update_event_times(event);
3380 if (event->state != PERF_EVENT_STATE_ACTIVE)
3389 pmu->start_txn(pmu, PERF_PMU_TXN_READ);
3393 list_for_each_entry(sub, &event->sibling_list, group_entry) {
3394 update_event_times(sub);
3395 if (sub->state == PERF_EVENT_STATE_ACTIVE) {
3397 * Use sibling's PMU rather than @event's since
3398 * sibling could be on different (eg: software) PMU.
3400 sub->pmu->read(sub);
3404 data->ret = pmu->commit_txn(pmu);
3407 raw_spin_unlock(&ctx->lock);
3410 static inline u64 perf_event_count(struct perf_event *event)
3412 if (event->pmu->count)
3413 return event->pmu->count(event);
3415 return __perf_event_count(event);
3419 * NMI-safe method to read a local event, that is an event that
3421 * - either for the current task, or for this CPU
3422 * - does not have inherit set, for inherited task events
3423 * will not be local and we cannot read them atomically
3424 * - must not have a pmu::count method
3426 u64 perf_event_read_local(struct perf_event *event)
3428 unsigned long flags;
3432 * Disabling interrupts avoids all counter scheduling (context
3433 * switches, timer based rotation and IPIs).
3435 local_irq_save(flags);
3437 /* If this is a per-task event, it must be for current */
3438 WARN_ON_ONCE((event->attach_state & PERF_ATTACH_TASK) &&
3439 event->hw.target != current);
3441 /* If this is a per-CPU event, it must be for this CPU */
3442 WARN_ON_ONCE(!(event->attach_state & PERF_ATTACH_TASK) &&
3443 event->cpu != smp_processor_id());
3446 * It must not be an event with inherit set, we cannot read
3447 * all child counters from atomic context.
3449 WARN_ON_ONCE(event->attr.inherit);
3452 * It must not have a pmu::count method, those are not
3455 WARN_ON_ONCE(event->pmu->count);
3458 * If the event is currently on this CPU, its either a per-task event,
3459 * or local to this CPU. Furthermore it means its ACTIVE (otherwise
3462 if (event->oncpu == smp_processor_id())
3463 event->pmu->read(event);
3465 val = local64_read(&event->count);
3466 local_irq_restore(flags);
3471 static int perf_event_read(struct perf_event *event, bool group)
3476 * If event is enabled and currently active on a CPU, update the
3477 * value in the event structure:
3479 if (event->state == PERF_EVENT_STATE_ACTIVE) {
3480 struct perf_read_data data = {
3485 smp_call_function_single(event->oncpu,
3486 __perf_event_read, &data, 1);
3488 } else if (event->state == PERF_EVENT_STATE_INACTIVE) {
3489 struct perf_event_context *ctx = event->ctx;
3490 unsigned long flags;
3492 raw_spin_lock_irqsave(&ctx->lock, flags);
3494 * may read while context is not active
3495 * (e.g., thread is blocked), in that case
3496 * we cannot update context time
3498 if (ctx->is_active) {
3499 update_context_time(ctx);
3500 update_cgrp_time_from_event(event);
3503 update_group_times(event);
3505 update_event_times(event);
3506 raw_spin_unlock_irqrestore(&ctx->lock, flags);
3513 * Initialize the perf_event context in a task_struct:
3515 static void __perf_event_init_context(struct perf_event_context *ctx)
3517 raw_spin_lock_init(&ctx->lock);
3518 mutex_init(&ctx->mutex);
3519 INIT_LIST_HEAD(&ctx->active_ctx_list);
3520 INIT_LIST_HEAD(&ctx->pinned_groups);
3521 INIT_LIST_HEAD(&ctx->flexible_groups);
3522 INIT_LIST_HEAD(&ctx->event_list);
3523 atomic_set(&ctx->refcount, 1);
3526 static struct perf_event_context *
3527 alloc_perf_context(struct pmu *pmu, struct task_struct *task)
3529 struct perf_event_context *ctx;
3531 ctx = kzalloc(sizeof(struct perf_event_context), GFP_KERNEL);
3535 __perf_event_init_context(ctx);
3538 get_task_struct(task);
3545 static struct task_struct *
3546 find_lively_task_by_vpid(pid_t vpid)
3548 struct task_struct *task;
3554 task = find_task_by_vpid(vpid);
3556 get_task_struct(task);
3560 return ERR_PTR(-ESRCH);
3566 * Returns a matching context with refcount and pincount.
3568 static struct perf_event_context *
3569 find_get_context(struct pmu *pmu, struct task_struct *task,
3570 struct perf_event *event)
3572 struct perf_event_context *ctx, *clone_ctx = NULL;
3573 struct perf_cpu_context *cpuctx;
3574 void *task_ctx_data = NULL;
3575 unsigned long flags;
3577 int cpu = event->cpu;
3580 /* Must be root to operate on a CPU event: */
3581 if (perf_paranoid_cpu() && !capable(CAP_SYS_ADMIN))
3582 return ERR_PTR(-EACCES);
3585 * We could be clever and allow to attach a event to an
3586 * offline CPU and activate it when the CPU comes up, but
3589 if (!cpu_online(cpu))
3590 return ERR_PTR(-ENODEV);
3592 cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
3601 ctxn = pmu->task_ctx_nr;
3605 if (event->attach_state & PERF_ATTACH_TASK_DATA) {
3606 task_ctx_data = kzalloc(pmu->task_ctx_size, GFP_KERNEL);
3607 if (!task_ctx_data) {
3614 ctx = perf_lock_task_context(task, ctxn, &flags);
3616 clone_ctx = unclone_ctx(ctx);
3619 if (task_ctx_data && !ctx->task_ctx_data) {
3620 ctx->task_ctx_data = task_ctx_data;
3621 task_ctx_data = NULL;
3623 raw_spin_unlock_irqrestore(&ctx->lock, flags);
3628 ctx = alloc_perf_context(pmu, task);
3633 if (task_ctx_data) {
3634 ctx->task_ctx_data = task_ctx_data;
3635 task_ctx_data = NULL;
3639 mutex_lock(&task->perf_event_mutex);
3641 * If it has already passed perf_event_exit_task().
3642 * we must see PF_EXITING, it takes this mutex too.
3644 if (task->flags & PF_EXITING)
3646 else if (task->perf_event_ctxp[ctxn])
3651 rcu_assign_pointer(task->perf_event_ctxp[ctxn], ctx);
3653 mutex_unlock(&task->perf_event_mutex);
3655 if (unlikely(err)) {
3664 kfree(task_ctx_data);
3668 kfree(task_ctx_data);
3669 return ERR_PTR(err);
3672 static void perf_event_free_filter(struct perf_event *event);
3673 static void perf_event_free_bpf_prog(struct perf_event *event);
3675 static void free_event_rcu(struct rcu_head *head)
3677 struct perf_event *event;
3679 event = container_of(head, struct perf_event, rcu_head);
3681 put_pid_ns(event->ns);
3682 perf_event_free_filter(event);
3686 static void ring_buffer_attach(struct perf_event *event,
3687 struct ring_buffer *rb);
3689 static void unaccount_event_cpu(struct perf_event *event, int cpu)
3694 if (is_cgroup_event(event))
3695 atomic_dec(&per_cpu(perf_cgroup_events, cpu));
3698 #ifdef CONFIG_NO_HZ_FULL
3699 static DEFINE_SPINLOCK(nr_freq_lock);
3702 static void unaccount_freq_event_nohz(void)
3704 #ifdef CONFIG_NO_HZ_FULL
3705 spin_lock(&nr_freq_lock);
3706 if (atomic_dec_and_test(&nr_freq_events))
3707 tick_nohz_dep_clear(TICK_DEP_BIT_PERF_EVENTS);
3708 spin_unlock(&nr_freq_lock);
3712 static void unaccount_freq_event(void)
3714 if (tick_nohz_full_enabled())
3715 unaccount_freq_event_nohz();
3717 atomic_dec(&nr_freq_events);
3720 static void unaccount_event(struct perf_event *event)
3727 if (event->attach_state & PERF_ATTACH_TASK)
3729 if (event->attr.mmap || event->attr.mmap_data)
3730 atomic_dec(&nr_mmap_events);
3731 if (event->attr.comm)
3732 atomic_dec(&nr_comm_events);
3733 if (event->attr.task)
3734 atomic_dec(&nr_task_events);
3735 if (event->attr.freq)
3736 unaccount_freq_event();
3737 if (event->attr.context_switch) {
3739 atomic_dec(&nr_switch_events);
3741 if (is_cgroup_event(event))
3743 if (has_branch_stack(event))
3747 if (!atomic_add_unless(&perf_sched_count, -1, 1))
3748 schedule_delayed_work(&perf_sched_work, HZ);
3751 unaccount_event_cpu(event, event->cpu);
3754 static void perf_sched_delayed(struct work_struct *work)
3756 mutex_lock(&perf_sched_mutex);
3757 if (atomic_dec_and_test(&perf_sched_count))
3758 static_branch_disable(&perf_sched_events);
3759 mutex_unlock(&perf_sched_mutex);
3763 * The following implement mutual exclusion of events on "exclusive" pmus
3764 * (PERF_PMU_CAP_EXCLUSIVE). Such pmus can only have one event scheduled
3765 * at a time, so we disallow creating events that might conflict, namely:
3767 * 1) cpu-wide events in the presence of per-task events,
3768 * 2) per-task events in the presence of cpu-wide events,
3769 * 3) two matching events on the same context.
3771 * The former two cases are handled in the allocation path (perf_event_alloc(),
3772 * _free_event()), the latter -- before the first perf_install_in_context().
3774 static int exclusive_event_init(struct perf_event *event)
3776 struct pmu *pmu = event->pmu;
3778 if (!(pmu->capabilities & PERF_PMU_CAP_EXCLUSIVE))
3782 * Prevent co-existence of per-task and cpu-wide events on the
3783 * same exclusive pmu.
3785 * Negative pmu::exclusive_cnt means there are cpu-wide
3786 * events on this "exclusive" pmu, positive means there are
3789 * Since this is called in perf_event_alloc() path, event::ctx
3790 * doesn't exist yet; it is, however, safe to use PERF_ATTACH_TASK
3791 * to mean "per-task event", because unlike other attach states it
3792 * never gets cleared.
3794 if (event->attach_state & PERF_ATTACH_TASK) {
3795 if (!atomic_inc_unless_negative(&pmu->exclusive_cnt))
3798 if (!atomic_dec_unless_positive(&pmu->exclusive_cnt))
3805 static void exclusive_event_destroy(struct perf_event *event)
3807 struct pmu *pmu = event->pmu;
3809 if (!(pmu->capabilities & PERF_PMU_CAP_EXCLUSIVE))
3812 /* see comment in exclusive_event_init() */
3813 if (event->attach_state & PERF_ATTACH_TASK)
3814 atomic_dec(&pmu->exclusive_cnt);
3816 atomic_inc(&pmu->exclusive_cnt);
3819 static bool exclusive_event_match(struct perf_event *e1, struct perf_event *e2)
3821 if ((e1->pmu->capabilities & PERF_PMU_CAP_EXCLUSIVE) &&
3822 (e1->cpu == e2->cpu ||
3829 /* Called under the same ctx::mutex as perf_install_in_context() */
3830 static bool exclusive_event_installable(struct perf_event *event,
3831 struct perf_event_context *ctx)
3833 struct perf_event *iter_event;
3834 struct pmu *pmu = event->pmu;
3836 if (!(pmu->capabilities & PERF_PMU_CAP_EXCLUSIVE))
3839 list_for_each_entry(iter_event, &ctx->event_list, event_entry) {
3840 if (exclusive_event_match(iter_event, event))
3847 static void perf_addr_filters_splice(struct perf_event *event,
3848 struct list_head *head);
3850 static void _free_event(struct perf_event *event)
3852 irq_work_sync(&event->pending);
3854 unaccount_event(event);
3858 * Can happen when we close an event with re-directed output.
3860 * Since we have a 0 refcount, perf_mmap_close() will skip
3861 * over us; possibly making our ring_buffer_put() the last.
3863 mutex_lock(&event->mmap_mutex);
3864 ring_buffer_attach(event, NULL);
3865 mutex_unlock(&event->mmap_mutex);
3868 if (is_cgroup_event(event))
3869 perf_detach_cgroup(event);
3871 if (!event->parent) {
3872 if (event->attr.sample_type & PERF_SAMPLE_CALLCHAIN)
3873 put_callchain_buffers();
3876 perf_event_free_bpf_prog(event);
3877 perf_addr_filters_splice(event, NULL);
3878 kfree(event->addr_filters_offs);
3881 event->destroy(event);
3884 put_ctx(event->ctx);
3886 exclusive_event_destroy(event);
3887 module_put(event->pmu->module);
3889 call_rcu(&event->rcu_head, free_event_rcu);
3893 * Used to free events which have a known refcount of 1, such as in error paths
3894 * where the event isn't exposed yet and inherited events.
3896 static void free_event(struct perf_event *event)
3898 if (WARN(atomic_long_cmpxchg(&event->refcount, 1, 0) != 1,
3899 "unexpected event refcount: %ld; ptr=%p\n",
3900 atomic_long_read(&event->refcount), event)) {
3901 /* leak to avoid use-after-free */
3909 * Remove user event from the owner task.
3911 static void perf_remove_from_owner(struct perf_event *event)
3913 struct task_struct *owner;
3917 * Matches the smp_store_release() in perf_event_exit_task(). If we
3918 * observe !owner it means the list deletion is complete and we can
3919 * indeed free this event, otherwise we need to serialize on
3920 * owner->perf_event_mutex.
3922 owner = lockless_dereference(event->owner);
3925 * Since delayed_put_task_struct() also drops the last
3926 * task reference we can safely take a new reference
3927 * while holding the rcu_read_lock().
3929 get_task_struct(owner);
3935 * If we're here through perf_event_exit_task() we're already
3936 * holding ctx->mutex which would be an inversion wrt. the
3937 * normal lock order.
3939 * However we can safely take this lock because its the child
3942 mutex_lock_nested(&owner->perf_event_mutex, SINGLE_DEPTH_NESTING);
3945 * We have to re-check the event->owner field, if it is cleared
3946 * we raced with perf_event_exit_task(), acquiring the mutex
3947 * ensured they're done, and we can proceed with freeing the
3951 list_del_init(&event->owner_entry);
3952 smp_store_release(&event->owner, NULL);
3954 mutex_unlock(&owner->perf_event_mutex);
3955 put_task_struct(owner);
3959 static void put_event(struct perf_event *event)
3961 if (!atomic_long_dec_and_test(&event->refcount))
3968 * Kill an event dead; while event:refcount will preserve the event
3969 * object, it will not preserve its functionality. Once the last 'user'
3970 * gives up the object, we'll destroy the thing.
3972 int perf_event_release_kernel(struct perf_event *event)
3974 struct perf_event_context *ctx = event->ctx;
3975 struct perf_event *child, *tmp;
3978 * If we got here through err_file: fput(event_file); we will not have
3979 * attached to a context yet.
3982 WARN_ON_ONCE(event->attach_state &
3983 (PERF_ATTACH_CONTEXT|PERF_ATTACH_GROUP));
3987 if (!is_kernel_event(event))
3988 perf_remove_from_owner(event);
3990 ctx = perf_event_ctx_lock(event);
3991 WARN_ON_ONCE(ctx->parent_ctx);
3992 perf_remove_from_context(event, DETACH_GROUP);
3994 raw_spin_lock_irq(&ctx->lock);
3996 * Mark this even as STATE_DEAD, there is no external reference to it
3999 * Anybody acquiring event->child_mutex after the below loop _must_
4000 * also see this, most importantly inherit_event() which will avoid
4001 * placing more children on the list.
4003 * Thus this guarantees that we will in fact observe and kill _ALL_
4006 event->state = PERF_EVENT_STATE_DEAD;
4007 raw_spin_unlock_irq(&ctx->lock);
4009 perf_event_ctx_unlock(event, ctx);
4012 mutex_lock(&event->child_mutex);
4013 list_for_each_entry(child, &event->child_list, child_list) {
4016 * Cannot change, child events are not migrated, see the
4017 * comment with perf_event_ctx_lock_nested().
4019 ctx = lockless_dereference(child->ctx);
4021 * Since child_mutex nests inside ctx::mutex, we must jump
4022 * through hoops. We start by grabbing a reference on the ctx.
4024 * Since the event cannot get freed while we hold the
4025 * child_mutex, the context must also exist and have a !0
4031 * Now that we have a ctx ref, we can drop child_mutex, and
4032 * acquire ctx::mutex without fear of it going away. Then we
4033 * can re-acquire child_mutex.
4035 mutex_unlock(&event->child_mutex);
4036 mutex_lock(&ctx->mutex);
4037 mutex_lock(&event->child_mutex);
4040 * Now that we hold ctx::mutex and child_mutex, revalidate our
4041 * state, if child is still the first entry, it didn't get freed
4042 * and we can continue doing so.
4044 tmp = list_first_entry_or_null(&event->child_list,
4045 struct perf_event, child_list);
4047 perf_remove_from_context(child, DETACH_GROUP);
4048 list_del(&child->child_list);
4051 * This matches the refcount bump in inherit_event();
4052 * this can't be the last reference.
4057 mutex_unlock(&event->child_mutex);
4058 mutex_unlock(&ctx->mutex);
4062 mutex_unlock(&event->child_mutex);
4065 put_event(event); /* Must be the 'last' reference */
4068 EXPORT_SYMBOL_GPL(perf_event_release_kernel);
4071 * Called when the last reference to the file is gone.
4073 static int perf_release(struct inode *inode, struct file *file)
4075 perf_event_release_kernel(file->private_data);
4079 u64 perf_event_read_value(struct perf_event *event, u64 *enabled, u64 *running)
4081 struct perf_event *child;
4087 mutex_lock(&event->child_mutex);
4089 (void)perf_event_read(event, false);
4090 total += perf_event_count(event);
4092 *enabled += event->total_time_enabled +
4093 atomic64_read(&event->child_total_time_enabled);
4094 *running += event->total_time_running +
4095 atomic64_read(&event->child_total_time_running);
4097 list_for_each_entry(child, &event->child_list, child_list) {
4098 (void)perf_event_read(child, false);
4099 total += perf_event_count(child);
4100 *enabled += child->total_time_enabled;
4101 *running += child->total_time_running;
4103 mutex_unlock(&event->child_mutex);
4107 EXPORT_SYMBOL_GPL(perf_event_read_value);
4109 static int __perf_read_group_add(struct perf_event *leader,
4110 u64 read_format, u64 *values)
4112 struct perf_event *sub;
4113 int n = 1; /* skip @nr */
4116 ret = perf_event_read(leader, true);
4121 * Since we co-schedule groups, {enabled,running} times of siblings
4122 * will be identical to those of the leader, so we only publish one
4125 if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED) {
4126 values[n++] += leader->total_time_enabled +
4127 atomic64_read(&leader->child_total_time_enabled);
4130 if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING) {
4131 values[n++] += leader->total_time_running +
4132 atomic64_read(&leader->child_total_time_running);
4136 * Write {count,id} tuples for every sibling.
4138 values[n++] += perf_event_count(leader);
4139 if (read_format & PERF_FORMAT_ID)
4140 values[n++] = primary_event_id(leader);
4142 list_for_each_entry(sub, &leader->sibling_list, group_entry) {
4143 values[n++] += perf_event_count(sub);
4144 if (read_format & PERF_FORMAT_ID)
4145 values[n++] = primary_event_id(sub);
4151 static int perf_read_group(struct perf_event *event,
4152 u64 read_format, char __user *buf)
4154 struct perf_event *leader = event->group_leader, *child;
4155 struct perf_event_context *ctx = leader->ctx;
4159 lockdep_assert_held(&ctx->mutex);
4161 values = kzalloc(event->read_size, GFP_KERNEL);
4165 values[0] = 1 + leader->nr_siblings;
4168 * By locking the child_mutex of the leader we effectively
4169 * lock the child list of all siblings.. XXX explain how.
4171 mutex_lock(&leader->child_mutex);
4173 ret = __perf_read_group_add(leader, read_format, values);
4177 list_for_each_entry(child, &leader->child_list, child_list) {
4178 ret = __perf_read_group_add(child, read_format, values);
4183 mutex_unlock(&leader->child_mutex);
4185 ret = event->read_size;
4186 if (copy_to_user(buf, values, event->read_size))
4191 mutex_unlock(&leader->child_mutex);
4197 static int perf_read_one(struct perf_event *event,
4198 u64 read_format, char __user *buf)
4200 u64 enabled, running;
4204 values[n++] = perf_event_read_value(event, &enabled, &running);
4205 if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED)
4206 values[n++] = enabled;
4207 if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING)
4208 values[n++] = running;
4209 if (read_format & PERF_FORMAT_ID)
4210 values[n++] = primary_event_id(event);
4212 if (copy_to_user(buf, values, n * sizeof(u64)))
4215 return n * sizeof(u64);
4218 static bool is_event_hup(struct perf_event *event)
4222 if (event->state > PERF_EVENT_STATE_EXIT)
4225 mutex_lock(&event->child_mutex);
4226 no_children = list_empty(&event->child_list);
4227 mutex_unlock(&event->child_mutex);
4232 * Read the performance event - simple non blocking version for now
4235 __perf_read(struct perf_event *event, char __user *buf, size_t count)
4237 u64 read_format = event->attr.read_format;
4241 * Return end-of-file for a read on a event that is in
4242 * error state (i.e. because it was pinned but it couldn't be
4243 * scheduled on to the CPU at some point).
4245 if (event->state == PERF_EVENT_STATE_ERROR)
4248 if (count < event->read_size)
4251 WARN_ON_ONCE(event->ctx->parent_ctx);
4252 if (read_format & PERF_FORMAT_GROUP)
4253 ret = perf_read_group(event, read_format, buf);
4255 ret = perf_read_one(event, read_format, buf);
4261 perf_read(struct file *file, char __user *buf, size_t count, loff_t *ppos)
4263 struct perf_event *event = file->private_data;
4264 struct perf_event_context *ctx;
4267 ctx = perf_event_ctx_lock(event);
4268 ret = __perf_read(event, buf, count);
4269 perf_event_ctx_unlock(event, ctx);
4274 static unsigned int perf_poll(struct file *file, poll_table *wait)
4276 struct perf_event *event = file->private_data;
4277 struct ring_buffer *rb;
4278 unsigned int events = POLLHUP;
4280 poll_wait(file, &event->waitq, wait);
4282 if (is_event_hup(event))
4286 * Pin the event->rb by taking event->mmap_mutex; otherwise
4287 * perf_event_set_output() can swizzle our rb and make us miss wakeups.
4289 mutex_lock(&event->mmap_mutex);
4292 events = atomic_xchg(&rb->poll, 0);
4293 mutex_unlock(&event->mmap_mutex);
4297 static void _perf_event_reset(struct perf_event *event)
4299 (void)perf_event_read(event, false);
4300 local64_set(&event->count, 0);
4301 perf_event_update_userpage(event);
4305 * Holding the top-level event's child_mutex means that any
4306 * descendant process that has inherited this event will block
4307 * in perf_event_exit_event() if it goes to exit, thus satisfying the
4308 * task existence requirements of perf_event_enable/disable.
4310 static void perf_event_for_each_child(struct perf_event *event,
4311 void (*func)(struct perf_event *))
4313 struct perf_event *child;
4315 WARN_ON_ONCE(event->ctx->parent_ctx);
4317 mutex_lock(&event->child_mutex);
4319 list_for_each_entry(child, &event->child_list, child_list)
4321 mutex_unlock(&event->child_mutex);
4324 static void perf_event_for_each(struct perf_event *event,
4325 void (*func)(struct perf_event *))
4327 struct perf_event_context *ctx = event->ctx;
4328 struct perf_event *sibling;
4330 lockdep_assert_held(&ctx->mutex);
4332 event = event->group_leader;
4334 perf_event_for_each_child(event, func);
4335 list_for_each_entry(sibling, &event->sibling_list, group_entry)
4336 perf_event_for_each_child(sibling, func);
4339 static void __perf_event_period(struct perf_event *event,
4340 struct perf_cpu_context *cpuctx,
4341 struct perf_event_context *ctx,
4344 u64 value = *((u64 *)info);
4347 if (event->attr.freq) {
4348 event->attr.sample_freq = value;
4350 event->attr.sample_period = value;
4351 event->hw.sample_period = value;
4354 active = (event->state == PERF_EVENT_STATE_ACTIVE);
4356 perf_pmu_disable(ctx->pmu);
4358 * We could be throttled; unthrottle now to avoid the tick
4359 * trying to unthrottle while we already re-started the event.
4361 if (event->hw.interrupts == MAX_INTERRUPTS) {
4362 event->hw.interrupts = 0;
4363 perf_log_throttle(event, 1);
4365 event->pmu->stop(event, PERF_EF_UPDATE);
4368 local64_set(&event->hw.period_left, 0);
4371 event->pmu->start(event, PERF_EF_RELOAD);
4372 perf_pmu_enable(ctx->pmu);
4376 static int perf_event_period(struct perf_event *event, u64 __user *arg)
4380 if (!is_sampling_event(event))
4383 if (copy_from_user(&value, arg, sizeof(value)))
4389 if (event->attr.freq && value > sysctl_perf_event_sample_rate)
4392 event_function_call(event, __perf_event_period, &value);
4397 static const struct file_operations perf_fops;
4399 static inline int perf_fget_light(int fd, struct fd *p)
4401 struct fd f = fdget(fd);
4405 if (f.file->f_op != &perf_fops) {
4413 static int perf_event_set_output(struct perf_event *event,
4414 struct perf_event *output_event);
4415 static int perf_event_set_filter(struct perf_event *event, void __user *arg);
4416 static int perf_event_set_bpf_prog(struct perf_event *event, u32 prog_fd);
4418 static long _perf_ioctl(struct perf_event *event, unsigned int cmd, unsigned long arg)
4420 void (*func)(struct perf_event *);
4424 case PERF_EVENT_IOC_ENABLE:
4425 func = _perf_event_enable;
4427 case PERF_EVENT_IOC_DISABLE:
4428 func = _perf_event_disable;
4430 case PERF_EVENT_IOC_RESET:
4431 func = _perf_event_reset;
4434 case PERF_EVENT_IOC_REFRESH:
4435 return _perf_event_refresh(event, arg);
4437 case PERF_EVENT_IOC_PERIOD:
4438 return perf_event_period(event, (u64 __user *)arg);
4440 case PERF_EVENT_IOC_ID:
4442 u64 id = primary_event_id(event);
4444 if (copy_to_user((void __user *)arg, &id, sizeof(id)))
4449 case PERF_EVENT_IOC_SET_OUTPUT:
4453 struct perf_event *output_event;
4455 ret = perf_fget_light(arg, &output);
4458 output_event = output.file->private_data;
4459 ret = perf_event_set_output(event, output_event);
4462 ret = perf_event_set_output(event, NULL);
4467 case PERF_EVENT_IOC_SET_FILTER:
4468 return perf_event_set_filter(event, (void __user *)arg);
4470 case PERF_EVENT_IOC_SET_BPF:
4471 return perf_event_set_bpf_prog(event, arg);
4473 case PERF_EVENT_IOC_PAUSE_OUTPUT: {
4474 struct ring_buffer *rb;
4477 rb = rcu_dereference(event->rb);
4478 if (!rb || !rb->nr_pages) {
4482 rb_toggle_paused(rb, !!arg);
4490 if (flags & PERF_IOC_FLAG_GROUP)
4491 perf_event_for_each(event, func);
4493 perf_event_for_each_child(event, func);
4498 static long perf_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
4500 struct perf_event *event = file->private_data;
4501 struct perf_event_context *ctx;
4504 ctx = perf_event_ctx_lock(event);
4505 ret = _perf_ioctl(event, cmd, arg);
4506 perf_event_ctx_unlock(event, ctx);
4511 #ifdef CONFIG_COMPAT
4512 static long perf_compat_ioctl(struct file *file, unsigned int cmd,
4515 switch (_IOC_NR(cmd)) {
4516 case _IOC_NR(PERF_EVENT_IOC_SET_FILTER):
4517 case _IOC_NR(PERF_EVENT_IOC_ID):
4518 /* Fix up pointer size (usually 4 -> 8 in 32-on-64-bit case */
4519 if (_IOC_SIZE(cmd) == sizeof(compat_uptr_t)) {
4520 cmd &= ~IOCSIZE_MASK;
4521 cmd |= sizeof(void *) << IOCSIZE_SHIFT;
4525 return perf_ioctl(file, cmd, arg);
4528 # define perf_compat_ioctl NULL
4531 int perf_event_task_enable(void)
4533 struct perf_event_context *ctx;
4534 struct perf_event *event;
4536 mutex_lock(¤t->perf_event_mutex);
4537 list_for_each_entry(event, ¤t->perf_event_list, owner_entry) {
4538 ctx = perf_event_ctx_lock(event);
4539 perf_event_for_each_child(event, _perf_event_enable);
4540 perf_event_ctx_unlock(event, ctx);
4542 mutex_unlock(¤t->perf_event_mutex);
4547 int perf_event_task_disable(void)
4549 struct perf_event_context *ctx;
4550 struct perf_event *event;
4552 mutex_lock(¤t->perf_event_mutex);
4553 list_for_each_entry(event, ¤t->perf_event_list, owner_entry) {
4554 ctx = perf_event_ctx_lock(event);
4555 perf_event_for_each_child(event, _perf_event_disable);
4556 perf_event_ctx_unlock(event, ctx);
4558 mutex_unlock(¤t->perf_event_mutex);
4563 static int perf_event_index(struct perf_event *event)
4565 if (event->hw.state & PERF_HES_STOPPED)
4568 if (event->state != PERF_EVENT_STATE_ACTIVE)
4571 return event->pmu->event_idx(event);
4574 static void calc_timer_values(struct perf_event *event,
4581 *now = perf_clock();
4582 ctx_time = event->shadow_ctx_time + *now;
4583 *enabled = ctx_time - event->tstamp_enabled;
4584 *running = ctx_time - event->tstamp_running;
4587 static void perf_event_init_userpage(struct perf_event *event)
4589 struct perf_event_mmap_page *userpg;
4590 struct ring_buffer *rb;
4593 rb = rcu_dereference(event->rb);
4597 userpg = rb->user_page;
4599 /* Allow new userspace to detect that bit 0 is deprecated */
4600 userpg->cap_bit0_is_deprecated = 1;
4601 userpg->size = offsetof(struct perf_event_mmap_page, __reserved);
4602 userpg->data_offset = PAGE_SIZE;
4603 userpg->data_size = perf_data_size(rb);
4609 void __weak arch_perf_update_userpage(
4610 struct perf_event *event, struct perf_event_mmap_page *userpg, u64 now)
4615 * Callers need to ensure there can be no nesting of this function, otherwise
4616 * the seqlock logic goes bad. We can not serialize this because the arch
4617 * code calls this from NMI context.
4619 void perf_event_update_userpage(struct perf_event *event)
4621 struct perf_event_mmap_page *userpg;
4622 struct ring_buffer *rb;
4623 u64 enabled, running, now;
4626 rb = rcu_dereference(event->rb);
4631 * compute total_time_enabled, total_time_running
4632 * based on snapshot values taken when the event
4633 * was last scheduled in.
4635 * we cannot simply called update_context_time()
4636 * because of locking issue as we can be called in
4639 calc_timer_values(event, &now, &enabled, &running);
4641 userpg = rb->user_page;
4643 * Disable preemption so as to not let the corresponding user-space
4644 * spin too long if we get preempted.
4649 userpg->index = perf_event_index(event);
4650 userpg->offset = perf_event_count(event);
4652 userpg->offset -= local64_read(&event->hw.prev_count);
4654 userpg->time_enabled = enabled +
4655 atomic64_read(&event->child_total_time_enabled);
4657 userpg->time_running = running +
4658 atomic64_read(&event->child_total_time_running);
4660 arch_perf_update_userpage(event, userpg, now);
4669 static int perf_mmap_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
4671 struct perf_event *event = vma->vm_file->private_data;
4672 struct ring_buffer *rb;
4673 int ret = VM_FAULT_SIGBUS;
4675 if (vmf->flags & FAULT_FLAG_MKWRITE) {
4676 if (vmf->pgoff == 0)
4682 rb = rcu_dereference(event->rb);
4686 if (vmf->pgoff && (vmf->flags & FAULT_FLAG_WRITE))
4689 vmf->page = perf_mmap_to_page(rb, vmf->pgoff);
4693 get_page(vmf->page);
4694 vmf->page->mapping = vma->vm_file->f_mapping;
4695 vmf->page->index = vmf->pgoff;
4704 static void ring_buffer_attach(struct perf_event *event,
4705 struct ring_buffer *rb)
4707 struct ring_buffer *old_rb = NULL;
4708 unsigned long flags;
4712 * Should be impossible, we set this when removing
4713 * event->rb_entry and wait/clear when adding event->rb_entry.
4715 WARN_ON_ONCE(event->rcu_pending);
4718 spin_lock_irqsave(&old_rb->event_lock, flags);
4719 list_del_rcu(&event->rb_entry);
4720 spin_unlock_irqrestore(&old_rb->event_lock, flags);
4722 event->rcu_batches = get_state_synchronize_rcu();
4723 event->rcu_pending = 1;
4727 if (event->rcu_pending) {
4728 cond_synchronize_rcu(event->rcu_batches);
4729 event->rcu_pending = 0;
4732 spin_lock_irqsave(&rb->event_lock, flags);
4733 list_add_rcu(&event->rb_entry, &rb->event_list);
4734 spin_unlock_irqrestore(&rb->event_lock, flags);
4737 rcu_assign_pointer(event->rb, rb);
4740 ring_buffer_put(old_rb);
4742 * Since we detached before setting the new rb, so that we
4743 * could attach the new rb, we could have missed a wakeup.
4746 wake_up_all(&event->waitq);
4750 static void ring_buffer_wakeup(struct perf_event *event)
4752 struct ring_buffer *rb;
4755 rb = rcu_dereference(event->rb);
4757 list_for_each_entry_rcu(event, &rb->event_list, rb_entry)
4758 wake_up_all(&event->waitq);
4763 struct ring_buffer *ring_buffer_get(struct perf_event *event)
4765 struct ring_buffer *rb;
4768 rb = rcu_dereference(event->rb);
4770 if (!atomic_inc_not_zero(&rb->refcount))
4778 void ring_buffer_put(struct ring_buffer *rb)
4780 if (!atomic_dec_and_test(&rb->refcount))
4783 WARN_ON_ONCE(!list_empty(&rb->event_list));
4785 call_rcu(&rb->rcu_head, rb_free_rcu);
4788 static void perf_mmap_open(struct vm_area_struct *vma)
4790 struct perf_event *event = vma->vm_file->private_data;
4792 atomic_inc(&event->mmap_count);
4793 atomic_inc(&event->rb->mmap_count);
4796 atomic_inc(&event->rb->aux_mmap_count);
4798 if (event->pmu->event_mapped)
4799 event->pmu->event_mapped(event);
4802 static void perf_pmu_output_stop(struct perf_event *event);
4805 * A buffer can be mmap()ed multiple times; either directly through the same
4806 * event, or through other events by use of perf_event_set_output().
4808 * In order to undo the VM accounting done by perf_mmap() we need to destroy
4809 * the buffer here, where we still have a VM context. This means we need
4810 * to detach all events redirecting to us.
4812 static void perf_mmap_close(struct vm_area_struct *vma)
4814 struct perf_event *event = vma->vm_file->private_data;
4816 struct ring_buffer *rb = ring_buffer_get(event);
4817 struct user_struct *mmap_user = rb->mmap_user;
4818 int mmap_locked = rb->mmap_locked;
4819 unsigned long size = perf_data_size(rb);
4821 if (event->pmu->event_unmapped)
4822 event->pmu->event_unmapped(event);
4825 * rb->aux_mmap_count will always drop before rb->mmap_count and
4826 * event->mmap_count, so it is ok to use event->mmap_mutex to
4827 * serialize with perf_mmap here.
4829 if (rb_has_aux(rb) && vma->vm_pgoff == rb->aux_pgoff &&
4830 atomic_dec_and_mutex_lock(&rb->aux_mmap_count, &event->mmap_mutex)) {
4832 * Stop all AUX events that are writing to this buffer,
4833 * so that we can free its AUX pages and corresponding PMU
4834 * data. Note that after rb::aux_mmap_count dropped to zero,
4835 * they won't start any more (see perf_aux_output_begin()).
4837 perf_pmu_output_stop(event);
4839 /* now it's safe to free the pages */
4840 atomic_long_sub(rb->aux_nr_pages, &mmap_user->locked_vm);
4841 vma->vm_mm->pinned_vm -= rb->aux_mmap_locked;
4843 /* this has to be the last one */
4845 WARN_ON_ONCE(atomic_read(&rb->aux_refcount));
4847 mutex_unlock(&event->mmap_mutex);
4850 atomic_dec(&rb->mmap_count);
4852 if (!atomic_dec_and_mutex_lock(&event->mmap_count, &event->mmap_mutex))
4855 ring_buffer_attach(event, NULL);
4856 mutex_unlock(&event->mmap_mutex);
4858 /* If there's still other mmap()s of this buffer, we're done. */
4859 if (atomic_read(&rb->mmap_count))
4863 * No other mmap()s, detach from all other events that might redirect
4864 * into the now unreachable buffer. Somewhat complicated by the
4865 * fact that rb::event_lock otherwise nests inside mmap_mutex.
4869 list_for_each_entry_rcu(event, &rb->event_list, rb_entry) {
4870 if (!atomic_long_inc_not_zero(&event->refcount)) {
4872 * This event is en-route to free_event() which will
4873 * detach it and remove it from the list.
4879 mutex_lock(&event->mmap_mutex);
4881 * Check we didn't race with perf_event_set_output() which can
4882 * swizzle the rb from under us while we were waiting to
4883 * acquire mmap_mutex.
4885 * If we find a different rb; ignore this event, a next
4886 * iteration will no longer find it on the list. We have to
4887 * still restart the iteration to make sure we're not now
4888 * iterating the wrong list.
4890 if (event->rb == rb)
4891 ring_buffer_attach(event, NULL);
4893 mutex_unlock(&event->mmap_mutex);
4897 * Restart the iteration; either we're on the wrong list or
4898 * destroyed its integrity by doing a deletion.
4905 * It could be there's still a few 0-ref events on the list; they'll
4906 * get cleaned up by free_event() -- they'll also still have their
4907 * ref on the rb and will free it whenever they are done with it.
4909 * Aside from that, this buffer is 'fully' detached and unmapped,
4910 * undo the VM accounting.
4913 atomic_long_sub((size >> PAGE_SHIFT) + 1, &mmap_user->locked_vm);
4914 vma->vm_mm->pinned_vm -= mmap_locked;
4915 free_uid(mmap_user);
4918 ring_buffer_put(rb); /* could be last */
4921 static const struct vm_operations_struct perf_mmap_vmops = {
4922 .open = perf_mmap_open,
4923 .close = perf_mmap_close, /* non mergable */
4924 .fault = perf_mmap_fault,
4925 .page_mkwrite = perf_mmap_fault,
4928 static int perf_mmap(struct file *file, struct vm_area_struct *vma)
4930 struct perf_event *event = file->private_data;
4931 unsigned long user_locked, user_lock_limit;
4932 struct user_struct *user = current_user();
4933 unsigned long locked, lock_limit;
4934 struct ring_buffer *rb = NULL;
4935 unsigned long vma_size;
4936 unsigned long nr_pages;
4937 long user_extra = 0, extra = 0;
4938 int ret = 0, flags = 0;
4941 * Don't allow mmap() of inherited per-task counters. This would
4942 * create a performance issue due to all children writing to the
4945 if (event->cpu == -1 && event->attr.inherit)
4948 if (!(vma->vm_flags & VM_SHARED))
4951 vma_size = vma->vm_end - vma->vm_start;
4953 if (vma->vm_pgoff == 0) {
4954 nr_pages = (vma_size / PAGE_SIZE) - 1;
4957 * AUX area mapping: if rb->aux_nr_pages != 0, it's already
4958 * mapped, all subsequent mappings should have the same size
4959 * and offset. Must be above the normal perf buffer.
4961 u64 aux_offset, aux_size;
4966 nr_pages = vma_size / PAGE_SIZE;
4968 mutex_lock(&event->mmap_mutex);
4975 aux_offset = ACCESS_ONCE(rb->user_page->aux_offset);
4976 aux_size = ACCESS_ONCE(rb->user_page->aux_size);
4978 if (aux_offset < perf_data_size(rb) + PAGE_SIZE)
4981 if (aux_offset != vma->vm_pgoff << PAGE_SHIFT)
4984 /* already mapped with a different offset */
4985 if (rb_has_aux(rb) && rb->aux_pgoff != vma->vm_pgoff)
4988 if (aux_size != vma_size || aux_size != nr_pages * PAGE_SIZE)
4991 /* already mapped with a different size */
4992 if (rb_has_aux(rb) && rb->aux_nr_pages != nr_pages)
4995 if (!is_power_of_2(nr_pages))
4998 if (!atomic_inc_not_zero(&rb->mmap_count))
5001 if (rb_has_aux(rb)) {
5002 atomic_inc(&rb->aux_mmap_count);
5007 atomic_set(&rb->aux_mmap_count, 1);
5008 user_extra = nr_pages;
5014 * If we have rb pages ensure they're a power-of-two number, so we
5015 * can do bitmasks instead of modulo.
5017 if (nr_pages != 0 && !is_power_of_2(nr_pages))
5020 if (vma_size != PAGE_SIZE * (1 + nr_pages))
5023 WARN_ON_ONCE(event->ctx->parent_ctx);
5025 mutex_lock(&event->mmap_mutex);
5027 if (event->rb->nr_pages != nr_pages) {
5032 if (!atomic_inc_not_zero(&event->rb->mmap_count)) {
5034 * Raced against perf_mmap_close() through
5035 * perf_event_set_output(). Try again, hope for better
5038 mutex_unlock(&event->mmap_mutex);
5045 user_extra = nr_pages + 1;
5048 user_lock_limit = sysctl_perf_event_mlock >> (PAGE_SHIFT - 10);
5051 * Increase the limit linearly with more CPUs:
5053 user_lock_limit *= num_online_cpus();
5055 user_locked = atomic_long_read(&user->locked_vm) + user_extra;
5057 if (user_locked > user_lock_limit)
5058 extra = user_locked - user_lock_limit;
5060 lock_limit = rlimit(RLIMIT_MEMLOCK);
5061 lock_limit >>= PAGE_SHIFT;
5062 locked = vma->vm_mm->pinned_vm + extra;
5064 if ((locked > lock_limit) && perf_paranoid_tracepoint_raw() &&
5065 !capable(CAP_IPC_LOCK)) {
5070 WARN_ON(!rb && event->rb);
5072 if (vma->vm_flags & VM_WRITE)
5073 flags |= RING_BUFFER_WRITABLE;
5076 rb = rb_alloc(nr_pages,
5077 event->attr.watermark ? event->attr.wakeup_watermark : 0,
5085 atomic_set(&rb->mmap_count, 1);
5086 rb->mmap_user = get_current_user();
5087 rb->mmap_locked = extra;
5089 ring_buffer_attach(event, rb);
5091 perf_event_init_userpage(event);
5092 perf_event_update_userpage(event);
5094 ret = rb_alloc_aux(rb, event, vma->vm_pgoff, nr_pages,
5095 event->attr.aux_watermark, flags);
5097 rb->aux_mmap_locked = extra;
5102 atomic_long_add(user_extra, &user->locked_vm);
5103 vma->vm_mm->pinned_vm += extra;
5105 atomic_inc(&event->mmap_count);
5107 atomic_dec(&rb->mmap_count);
5110 mutex_unlock(&event->mmap_mutex);
5113 * Since pinned accounting is per vm we cannot allow fork() to copy our
5116 vma->vm_flags |= VM_DONTCOPY | VM_DONTEXPAND | VM_DONTDUMP;
5117 vma->vm_ops = &perf_mmap_vmops;
5119 if (event->pmu->event_mapped)
5120 event->pmu->event_mapped(event);
5125 static int perf_fasync(int fd, struct file *filp, int on)
5127 struct inode *inode = file_inode(filp);
5128 struct perf_event *event = filp->private_data;
5132 retval = fasync_helper(fd, filp, on, &event->fasync);
5133 inode_unlock(inode);
5141 static const struct file_operations perf_fops = {
5142 .llseek = no_llseek,
5143 .release = perf_release,
5146 .unlocked_ioctl = perf_ioctl,
5147 .compat_ioctl = perf_compat_ioctl,
5149 .fasync = perf_fasync,
5155 * If there's data, ensure we set the poll() state and publish everything
5156 * to user-space before waking everybody up.
5159 static inline struct fasync_struct **perf_event_fasync(struct perf_event *event)
5161 /* only the parent has fasync state */
5163 event = event->parent;
5164 return &event->fasync;
5167 void perf_event_wakeup(struct perf_event *event)
5169 ring_buffer_wakeup(event);
5171 if (event->pending_kill) {
5172 kill_fasync(perf_event_fasync(event), SIGIO, event->pending_kill);
5173 event->pending_kill = 0;
5177 static void perf_pending_event(struct irq_work *entry)
5179 struct perf_event *event = container_of(entry,
5180 struct perf_event, pending);
5183 rctx = perf_swevent_get_recursion_context();
5185 * If we 'fail' here, that's OK, it means recursion is already disabled
5186 * and we won't recurse 'further'.
5189 if (event->pending_disable) {
5190 event->pending_disable = 0;
5191 perf_event_disable_local(event);
5194 if (event->pending_wakeup) {
5195 event->pending_wakeup = 0;
5196 perf_event_wakeup(event);
5200 perf_swevent_put_recursion_context(rctx);
5204 * We assume there is only KVM supporting the callbacks.
5205 * Later on, we might change it to a list if there is
5206 * another virtualization implementation supporting the callbacks.
5208 struct perf_guest_info_callbacks *perf_guest_cbs;
5210 int perf_register_guest_info_callbacks(struct perf_guest_info_callbacks *cbs)
5212 perf_guest_cbs = cbs;
5215 EXPORT_SYMBOL_GPL(perf_register_guest_info_callbacks);
5217 int perf_unregister_guest_info_callbacks(struct perf_guest_info_callbacks *cbs)
5219 perf_guest_cbs = NULL;
5222 EXPORT_SYMBOL_GPL(perf_unregister_guest_info_callbacks);
5225 perf_output_sample_regs(struct perf_output_handle *handle,
5226 struct pt_regs *regs, u64 mask)
5230 for_each_set_bit(bit, (const unsigned long *) &mask,
5231 sizeof(mask) * BITS_PER_BYTE) {
5234 val = perf_reg_value(regs, bit);
5235 perf_output_put(handle, val);
5239 static void perf_sample_regs_user(struct perf_regs *regs_user,
5240 struct pt_regs *regs,
5241 struct pt_regs *regs_user_copy)
5243 if (user_mode(regs)) {
5244 regs_user->abi = perf_reg_abi(current);
5245 regs_user->regs = regs;
5246 } else if (current->mm) {
5247 perf_get_regs_user(regs_user, regs, regs_user_copy);
5249 regs_user->abi = PERF_SAMPLE_REGS_ABI_NONE;
5250 regs_user->regs = NULL;
5254 static void perf_sample_regs_intr(struct perf_regs *regs_intr,
5255 struct pt_regs *regs)
5257 regs_intr->regs = regs;
5258 regs_intr->abi = perf_reg_abi(current);
5263 * Get remaining task size from user stack pointer.
5265 * It'd be better to take stack vma map and limit this more
5266 * precisly, but there's no way to get it safely under interrupt,
5267 * so using TASK_SIZE as limit.
5269 static u64 perf_ustack_task_size(struct pt_regs *regs)
5271 unsigned long addr = perf_user_stack_pointer(regs);
5273 if (!addr || addr >= TASK_SIZE)
5276 return TASK_SIZE - addr;
5280 perf_sample_ustack_size(u16 stack_size, u16 header_size,
5281 struct pt_regs *regs)
5285 /* No regs, no stack pointer, no dump. */
5290 * Check if we fit in with the requested stack size into the:
5292 * If we don't, we limit the size to the TASK_SIZE.
5294 * - remaining sample size
5295 * If we don't, we customize the stack size to
5296 * fit in to the remaining sample size.
5299 task_size = min((u64) USHRT_MAX, perf_ustack_task_size(regs));
5300 stack_size = min(stack_size, (u16) task_size);
5302 /* Current header size plus static size and dynamic size. */
5303 header_size += 2 * sizeof(u64);
5305 /* Do we fit in with the current stack dump size? */
5306 if ((u16) (header_size + stack_size) < header_size) {
5308 * If we overflow the maximum size for the sample,
5309 * we customize the stack dump size to fit in.
5311 stack_size = USHRT_MAX - header_size - sizeof(u64);
5312 stack_size = round_up(stack_size, sizeof(u64));
5319 perf_output_sample_ustack(struct perf_output_handle *handle, u64 dump_size,
5320 struct pt_regs *regs)
5322 /* Case of a kernel thread, nothing to dump */
5325 perf_output_put(handle, size);
5334 * - the size requested by user or the best one we can fit
5335 * in to the sample max size
5337 * - user stack dump data
5339 * - the actual dumped size
5343 perf_output_put(handle, dump_size);
5346 sp = perf_user_stack_pointer(regs);
5347 rem = __output_copy_user(handle, (void *) sp, dump_size);
5348 dyn_size = dump_size - rem;
5350 perf_output_skip(handle, rem);
5353 perf_output_put(handle, dyn_size);
5357 static void __perf_event_header__init_id(struct perf_event_header *header,
5358 struct perf_sample_data *data,
5359 struct perf_event *event)
5361 u64 sample_type = event->attr.sample_type;
5363 data->type = sample_type;
5364 header->size += event->id_header_size;
5366 if (sample_type & PERF_SAMPLE_TID) {
5367 /* namespace issues */
5368 data->tid_entry.pid = perf_event_pid(event, current);
5369 data->tid_entry.tid = perf_event_tid(event, current);
5372 if (sample_type & PERF_SAMPLE_TIME)
5373 data->time = perf_event_clock(event);
5375 if (sample_type & (PERF_SAMPLE_ID | PERF_SAMPLE_IDENTIFIER))
5376 data->id = primary_event_id(event);
5378 if (sample_type & PERF_SAMPLE_STREAM_ID)
5379 data->stream_id = event->id;
5381 if (sample_type & PERF_SAMPLE_CPU) {
5382 data->cpu_entry.cpu = raw_smp_processor_id();
5383 data->cpu_entry.reserved = 0;
5387 void perf_event_header__init_id(struct perf_event_header *header,
5388 struct perf_sample_data *data,
5389 struct perf_event *event)
5391 if (event->attr.sample_id_all)
5392 __perf_event_header__init_id(header, data, event);
5395 static void __perf_event__output_id_sample(struct perf_output_handle *handle,
5396 struct perf_sample_data *data)
5398 u64 sample_type = data->type;
5400 if (sample_type & PERF_SAMPLE_TID)
5401 perf_output_put(handle, data->tid_entry);
5403 if (sample_type & PERF_SAMPLE_TIME)
5404 perf_output_put(handle, data->time);
5406 if (sample_type & PERF_SAMPLE_ID)
5407 perf_output_put(handle, data->id);
5409 if (sample_type & PERF_SAMPLE_STREAM_ID)
5410 perf_output_put(handle, data->stream_id);
5412 if (sample_type & PERF_SAMPLE_CPU)
5413 perf_output_put(handle, data->cpu_entry);
5415 if (sample_type & PERF_SAMPLE_IDENTIFIER)
5416 perf_output_put(handle, data->id);
5419 void perf_event__output_id_sample(struct perf_event *event,
5420 struct perf_output_handle *handle,
5421 struct perf_sample_data *sample)
5423 if (event->attr.sample_id_all)
5424 __perf_event__output_id_sample(handle, sample);
5427 static void perf_output_read_one(struct perf_output_handle *handle,
5428 struct perf_event *event,
5429 u64 enabled, u64 running)
5431 u64 read_format = event->attr.read_format;
5435 values[n++] = perf_event_count(event);
5436 if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED) {
5437 values[n++] = enabled +
5438 atomic64_read(&event->child_total_time_enabled);
5440 if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING) {
5441 values[n++] = running +
5442 atomic64_read(&event->child_total_time_running);
5444 if (read_format & PERF_FORMAT_ID)
5445 values[n++] = primary_event_id(event);
5447 __output_copy(handle, values, n * sizeof(u64));
5451 * XXX PERF_FORMAT_GROUP vs inherited events seems difficult.
5453 static void perf_output_read_group(struct perf_output_handle *handle,
5454 struct perf_event *event,
5455 u64 enabled, u64 running)
5457 struct perf_event *leader = event->group_leader, *sub;
5458 u64 read_format = event->attr.read_format;
5462 values[n++] = 1 + leader->nr_siblings;
5464 if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED)
5465 values[n++] = enabled;
5467 if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING)
5468 values[n++] = running;
5470 if (leader != event)
5471 leader->pmu->read(leader);
5473 values[n++] = perf_event_count(leader);
5474 if (read_format & PERF_FORMAT_ID)
5475 values[n++] = primary_event_id(leader);
5477 __output_copy(handle, values, n * sizeof(u64));
5479 list_for_each_entry(sub, &leader->sibling_list, group_entry) {
5482 if ((sub != event) &&
5483 (sub->state == PERF_EVENT_STATE_ACTIVE))
5484 sub->pmu->read(sub);
5486 values[n++] = perf_event_count(sub);
5487 if (read_format & PERF_FORMAT_ID)
5488 values[n++] = primary_event_id(sub);
5490 __output_copy(handle, values, n * sizeof(u64));
5494 #define PERF_FORMAT_TOTAL_TIMES (PERF_FORMAT_TOTAL_TIME_ENABLED|\
5495 PERF_FORMAT_TOTAL_TIME_RUNNING)
5497 static void perf_output_read(struct perf_output_handle *handle,
5498 struct perf_event *event)
5500 u64 enabled = 0, running = 0, now;
5501 u64 read_format = event->attr.read_format;
5504 * compute total_time_enabled, total_time_running
5505 * based on snapshot values taken when the event
5506 * was last scheduled in.
5508 * we cannot simply called update_context_time()
5509 * because of locking issue as we are called in
5512 if (read_format & PERF_FORMAT_TOTAL_TIMES)
5513 calc_timer_values(event, &now, &enabled, &running);
5515 if (event->attr.read_format & PERF_FORMAT_GROUP)
5516 perf_output_read_group(handle, event, enabled, running);
5518 perf_output_read_one(handle, event, enabled, running);
5521 void perf_output_sample(struct perf_output_handle *handle,
5522 struct perf_event_header *header,
5523 struct perf_sample_data *data,
5524 struct perf_event *event)
5526 u64 sample_type = data->type;
5528 perf_output_put(handle, *header);
5530 if (sample_type & PERF_SAMPLE_IDENTIFIER)
5531 perf_output_put(handle, data->id);
5533 if (sample_type & PERF_SAMPLE_IP)
5534 perf_output_put(handle, data->ip);
5536 if (sample_type & PERF_SAMPLE_TID)
5537 perf_output_put(handle, data->tid_entry);
5539 if (sample_type & PERF_SAMPLE_TIME)
5540 perf_output_put(handle, data->time);
5542 if (sample_type & PERF_SAMPLE_ADDR)
5543 perf_output_put(handle, data->addr);
5545 if (sample_type & PERF_SAMPLE_ID)
5546 perf_output_put(handle, data->id);
5548 if (sample_type & PERF_SAMPLE_STREAM_ID)
5549 perf_output_put(handle, data->stream_id);
5551 if (sample_type & PERF_SAMPLE_CPU)
5552 perf_output_put(handle, data->cpu_entry);
5554 if (sample_type & PERF_SAMPLE_PERIOD)
5555 perf_output_put(handle, data->period);
5557 if (sample_type & PERF_SAMPLE_READ)
5558 perf_output_read(handle, event);
5560 if (sample_type & PERF_SAMPLE_CALLCHAIN) {
5561 if (data->callchain) {
5564 if (data->callchain)
5565 size += data->callchain->nr;
5567 size *= sizeof(u64);
5569 __output_copy(handle, data->callchain, size);
5572 perf_output_put(handle, nr);
5576 if (sample_type & PERF_SAMPLE_RAW) {
5578 u32 raw_size = data->raw->size;
5579 u32 real_size = round_up(raw_size + sizeof(u32),
5580 sizeof(u64)) - sizeof(u32);
5583 perf_output_put(handle, real_size);
5584 __output_copy(handle, data->raw->data, raw_size);
5585 if (real_size - raw_size)
5586 __output_copy(handle, &zero, real_size - raw_size);
5592 .size = sizeof(u32),
5595 perf_output_put(handle, raw);
5599 if (sample_type & PERF_SAMPLE_BRANCH_STACK) {
5600 if (data->br_stack) {
5603 size = data->br_stack->nr
5604 * sizeof(struct perf_branch_entry);
5606 perf_output_put(handle, data->br_stack->nr);
5607 perf_output_copy(handle, data->br_stack->entries, size);
5610 * we always store at least the value of nr
5613 perf_output_put(handle, nr);
5617 if (sample_type & PERF_SAMPLE_REGS_USER) {
5618 u64 abi = data->regs_user.abi;
5621 * If there are no regs to dump, notice it through
5622 * first u64 being zero (PERF_SAMPLE_REGS_ABI_NONE).
5624 perf_output_put(handle, abi);
5627 u64 mask = event->attr.sample_regs_user;
5628 perf_output_sample_regs(handle,
5629 data->regs_user.regs,
5634 if (sample_type & PERF_SAMPLE_STACK_USER) {
5635 perf_output_sample_ustack(handle,
5636 data->stack_user_size,
5637 data->regs_user.regs);
5640 if (sample_type & PERF_SAMPLE_WEIGHT)
5641 perf_output_put(handle, data->weight);
5643 if (sample_type & PERF_SAMPLE_DATA_SRC)
5644 perf_output_put(handle, data->data_src.val);
5646 if (sample_type & PERF_SAMPLE_TRANSACTION)
5647 perf_output_put(handle, data->txn);
5649 if (sample_type & PERF_SAMPLE_REGS_INTR) {
5650 u64 abi = data->regs_intr.abi;
5652 * If there are no regs to dump, notice it through
5653 * first u64 being zero (PERF_SAMPLE_REGS_ABI_NONE).
5655 perf_output_put(handle, abi);
5658 u64 mask = event->attr.sample_regs_intr;
5660 perf_output_sample_regs(handle,
5661 data->regs_intr.regs,
5666 if (!event->attr.watermark) {
5667 int wakeup_events = event->attr.wakeup_events;
5669 if (wakeup_events) {
5670 struct ring_buffer *rb = handle->rb;
5671 int events = local_inc_return(&rb->events);
5673 if (events >= wakeup_events) {
5674 local_sub(wakeup_events, &rb->events);
5675 local_inc(&rb->wakeup);
5681 void perf_prepare_sample(struct perf_event_header *header,
5682 struct perf_sample_data *data,
5683 struct perf_event *event,
5684 struct pt_regs *regs)
5686 u64 sample_type = event->attr.sample_type;
5688 header->type = PERF_RECORD_SAMPLE;
5689 header->size = sizeof(*header) + event->header_size;
5692 header->misc |= perf_misc_flags(regs);
5694 __perf_event_header__init_id(header, data, event);
5696 if (sample_type & PERF_SAMPLE_IP)
5697 data->ip = perf_instruction_pointer(regs);
5699 if (sample_type & PERF_SAMPLE_CALLCHAIN) {
5702 data->callchain = perf_callchain(event, regs);
5704 if (data->callchain)
5705 size += data->callchain->nr;
5707 header->size += size * sizeof(u64);
5710 if (sample_type & PERF_SAMPLE_RAW) {
5711 int size = sizeof(u32);
5714 size += data->raw->size;
5716 size += sizeof(u32);
5718 header->size += round_up(size, sizeof(u64));
5721 if (sample_type & PERF_SAMPLE_BRANCH_STACK) {
5722 int size = sizeof(u64); /* nr */
5723 if (data->br_stack) {
5724 size += data->br_stack->nr
5725 * sizeof(struct perf_branch_entry);
5727 header->size += size;
5730 if (sample_type & (PERF_SAMPLE_REGS_USER | PERF_SAMPLE_STACK_USER))
5731 perf_sample_regs_user(&data->regs_user, regs,
5732 &data->regs_user_copy);
5734 if (sample_type & PERF_SAMPLE_REGS_USER) {
5735 /* regs dump ABI info */
5736 int size = sizeof(u64);
5738 if (data->regs_user.regs) {
5739 u64 mask = event->attr.sample_regs_user;
5740 size += hweight64(mask) * sizeof(u64);
5743 header->size += size;
5746 if (sample_type & PERF_SAMPLE_STACK_USER) {
5748 * Either we need PERF_SAMPLE_STACK_USER bit to be allways
5749 * processed as the last one or have additional check added
5750 * in case new sample type is added, because we could eat
5751 * up the rest of the sample size.
5753 u16 stack_size = event->attr.sample_stack_user;
5754 u16 size = sizeof(u64);
5756 stack_size = perf_sample_ustack_size(stack_size, header->size,
5757 data->regs_user.regs);
5760 * If there is something to dump, add space for the dump
5761 * itself and for the field that tells the dynamic size,
5762 * which is how many have been actually dumped.
5765 size += sizeof(u64) + stack_size;
5767 data->stack_user_size = stack_size;
5768 header->size += size;
5771 if (sample_type & PERF_SAMPLE_REGS_INTR) {
5772 /* regs dump ABI info */
5773 int size = sizeof(u64);
5775 perf_sample_regs_intr(&data->regs_intr, regs);
5777 if (data->regs_intr.regs) {
5778 u64 mask = event->attr.sample_regs_intr;
5780 size += hweight64(mask) * sizeof(u64);
5783 header->size += size;
5787 static void __always_inline
5788 __perf_event_output(struct perf_event *event,
5789 struct perf_sample_data *data,
5790 struct pt_regs *regs,
5791 int (*output_begin)(struct perf_output_handle *,
5792 struct perf_event *,
5795 struct perf_output_handle handle;
5796 struct perf_event_header header;
5798 /* protect the callchain buffers */
5801 perf_prepare_sample(&header, data, event, regs);
5803 if (output_begin(&handle, event, header.size))
5806 perf_output_sample(&handle, &header, data, event);
5808 perf_output_end(&handle);
5815 perf_event_output_forward(struct perf_event *event,
5816 struct perf_sample_data *data,
5817 struct pt_regs *regs)
5819 __perf_event_output(event, data, regs, perf_output_begin_forward);
5823 perf_event_output_backward(struct perf_event *event,
5824 struct perf_sample_data *data,
5825 struct pt_regs *regs)
5827 __perf_event_output(event, data, regs, perf_output_begin_backward);
5831 perf_event_output(struct perf_event *event,
5832 struct perf_sample_data *data,
5833 struct pt_regs *regs)
5835 __perf_event_output(event, data, regs, perf_output_begin);
5842 struct perf_read_event {
5843 struct perf_event_header header;
5850 perf_event_read_event(struct perf_event *event,
5851 struct task_struct *task)
5853 struct perf_output_handle handle;
5854 struct perf_sample_data sample;
5855 struct perf_read_event read_event = {
5857 .type = PERF_RECORD_READ,
5859 .size = sizeof(read_event) + event->read_size,
5861 .pid = perf_event_pid(event, task),
5862 .tid = perf_event_tid(event, task),
5866 perf_event_header__init_id(&read_event.header, &sample, event);
5867 ret = perf_output_begin(&handle, event, read_event.header.size);
5871 perf_output_put(&handle, read_event);
5872 perf_output_read(&handle, event);
5873 perf_event__output_id_sample(event, &handle, &sample);
5875 perf_output_end(&handle);
5878 typedef void (perf_event_aux_output_cb)(struct perf_event *event, void *data);
5881 perf_event_aux_ctx(struct perf_event_context *ctx,
5882 perf_event_aux_output_cb output,
5883 void *data, bool all)
5885 struct perf_event *event;
5887 list_for_each_entry_rcu(event, &ctx->event_list, event_entry) {
5889 if (event->state < PERF_EVENT_STATE_INACTIVE)
5891 if (!event_filter_match(event))
5895 output(event, data);
5900 perf_event_aux_task_ctx(perf_event_aux_output_cb output, void *data,
5901 struct perf_event_context *task_ctx)
5905 perf_event_aux_ctx(task_ctx, output, data, false);
5911 perf_event_aux(perf_event_aux_output_cb output, void *data,
5912 struct perf_event_context *task_ctx)
5914 struct perf_cpu_context *cpuctx;
5915 struct perf_event_context *ctx;
5920 * If we have task_ctx != NULL we only notify
5921 * the task context itself. The task_ctx is set
5922 * only for EXIT events before releasing task
5926 perf_event_aux_task_ctx(output, data, task_ctx);
5931 list_for_each_entry_rcu(pmu, &pmus, entry) {
5932 cpuctx = get_cpu_ptr(pmu->pmu_cpu_context);
5933 if (cpuctx->unique_pmu != pmu)
5935 perf_event_aux_ctx(&cpuctx->ctx, output, data, false);
5936 ctxn = pmu->task_ctx_nr;
5939 ctx = rcu_dereference(current->perf_event_ctxp[ctxn]);
5941 perf_event_aux_ctx(ctx, output, data, false);
5943 put_cpu_ptr(pmu->pmu_cpu_context);
5949 * Clear all file-based filters at exec, they'll have to be
5950 * re-instated when/if these objects are mmapped again.
5952 static void perf_event_addr_filters_exec(struct perf_event *event, void *data)
5954 struct perf_addr_filters_head *ifh = perf_event_addr_filters(event);
5955 struct perf_addr_filter *filter;
5956 unsigned int restart = 0, count = 0;
5957 unsigned long flags;
5959 if (!has_addr_filter(event))
5962 raw_spin_lock_irqsave(&ifh->lock, flags);
5963 list_for_each_entry(filter, &ifh->list, entry) {
5964 if (filter->inode) {
5965 event->addr_filters_offs[count] = 0;
5973 event->addr_filters_gen++;
5974 raw_spin_unlock_irqrestore(&ifh->lock, flags);
5977 perf_event_restart(event);
5980 void perf_event_exec(void)
5982 struct perf_event_context *ctx;
5986 for_each_task_context_nr(ctxn) {
5987 ctx = current->perf_event_ctxp[ctxn];
5991 perf_event_enable_on_exec(ctxn);
5993 perf_event_aux_ctx(ctx, perf_event_addr_filters_exec, NULL,
5999 struct remote_output {
6000 struct ring_buffer *rb;
6004 static void __perf_event_output_stop(struct perf_event *event, void *data)
6006 struct perf_event *parent = event->parent;
6007 struct remote_output *ro = data;
6008 struct ring_buffer *rb = ro->rb;
6009 struct stop_event_data sd = {
6013 if (!has_aux(event))
6020 * In case of inheritance, it will be the parent that links to the
6021 * ring-buffer, but it will be the child that's actually using it:
6023 if (rcu_dereference(parent->rb) == rb)
6024 ro->err = __perf_event_stop(&sd);
6027 static int __perf_pmu_output_stop(void *info)
6029 struct perf_event *event = info;
6030 struct pmu *pmu = event->pmu;
6031 struct perf_cpu_context *cpuctx = get_cpu_ptr(pmu->pmu_cpu_context);
6032 struct remote_output ro = {
6037 perf_event_aux_ctx(&cpuctx->ctx, __perf_event_output_stop, &ro, false);
6038 if (cpuctx->task_ctx)
6039 perf_event_aux_ctx(cpuctx->task_ctx, __perf_event_output_stop,
6046 static void perf_pmu_output_stop(struct perf_event *event)
6048 struct perf_event *iter;
6053 list_for_each_entry_rcu(iter, &event->rb->event_list, rb_entry) {
6055 * For per-CPU events, we need to make sure that neither they
6056 * nor their children are running; for cpu==-1 events it's
6057 * sufficient to stop the event itself if it's active, since
6058 * it can't have children.
6062 cpu = READ_ONCE(iter->oncpu);
6067 err = cpu_function_call(cpu, __perf_pmu_output_stop, event);
6068 if (err == -EAGAIN) {
6077 * task tracking -- fork/exit
6079 * enabled by: attr.comm | attr.mmap | attr.mmap2 | attr.mmap_data | attr.task
6082 struct perf_task_event {
6083 struct task_struct *task;
6084 struct perf_event_context *task_ctx;
6087 struct perf_event_header header;
6097 static int perf_event_task_match(struct perf_event *event)
6099 return event->attr.comm || event->attr.mmap ||
6100 event->attr.mmap2 || event->attr.mmap_data ||
6104 static void perf_event_task_output(struct perf_event *event,
6107 struct perf_task_event *task_event = data;
6108 struct perf_output_handle handle;
6109 struct perf_sample_data sample;
6110 struct task_struct *task = task_event->task;
6111 int ret, size = task_event->event_id.header.size;
6113 if (!perf_event_task_match(event))
6116 perf_event_header__init_id(&task_event->event_id.header, &sample, event);
6118 ret = perf_output_begin(&handle, event,
6119 task_event->event_id.header.size);
6123 task_event->event_id.pid = perf_event_pid(event, task);
6124 task_event->event_id.ppid = perf_event_pid(event, current);
6126 task_event->event_id.tid = perf_event_tid(event, task);
6127 task_event->event_id.ptid = perf_event_tid(event, current);
6129 task_event->event_id.time = perf_event_clock(event);
6131 perf_output_put(&handle, task_event->event_id);
6133 perf_event__output_id_sample(event, &handle, &sample);
6135 perf_output_end(&handle);
6137 task_event->event_id.header.size = size;
6140 static void perf_event_task(struct task_struct *task,
6141 struct perf_event_context *task_ctx,
6144 struct perf_task_event task_event;
6146 if (!atomic_read(&nr_comm_events) &&
6147 !atomic_read(&nr_mmap_events) &&
6148 !atomic_read(&nr_task_events))
6151 task_event = (struct perf_task_event){
6153 .task_ctx = task_ctx,
6156 .type = new ? PERF_RECORD_FORK : PERF_RECORD_EXIT,
6158 .size = sizeof(task_event.event_id),
6168 perf_event_aux(perf_event_task_output,
6173 void perf_event_fork(struct task_struct *task)
6175 perf_event_task(task, NULL, 1);
6182 struct perf_comm_event {
6183 struct task_struct *task;
6188 struct perf_event_header header;
6195 static int perf_event_comm_match(struct perf_event *event)
6197 return event->attr.comm;
6200 static void perf_event_comm_output(struct perf_event *event,
6203 struct perf_comm_event *comm_event = data;
6204 struct perf_output_handle handle;
6205 struct perf_sample_data sample;
6206 int size = comm_event->event_id.header.size;
6209 if (!perf_event_comm_match(event))
6212 perf_event_header__init_id(&comm_event->event_id.header, &sample, event);
6213 ret = perf_output_begin(&handle, event,
6214 comm_event->event_id.header.size);
6219 comm_event->event_id.pid = perf_event_pid(event, comm_event->task);
6220 comm_event->event_id.tid = perf_event_tid(event, comm_event->task);
6222 perf_output_put(&handle, comm_event->event_id);
6223 __output_copy(&handle, comm_event->comm,
6224 comm_event->comm_size);
6226 perf_event__output_id_sample(event, &handle, &sample);
6228 perf_output_end(&handle);
6230 comm_event->event_id.header.size = size;
6233 static void perf_event_comm_event(struct perf_comm_event *comm_event)
6235 char comm[TASK_COMM_LEN];
6238 memset(comm, 0, sizeof(comm));
6239 strlcpy(comm, comm_event->task->comm, sizeof(comm));
6240 size = ALIGN(strlen(comm)+1, sizeof(u64));
6242 comm_event->comm = comm;
6243 comm_event->comm_size = size;
6245 comm_event->event_id.header.size = sizeof(comm_event->event_id) + size;
6247 perf_event_aux(perf_event_comm_output,
6252 void perf_event_comm(struct task_struct *task, bool exec)
6254 struct perf_comm_event comm_event;
6256 if (!atomic_read(&nr_comm_events))
6259 comm_event = (struct perf_comm_event){
6265 .type = PERF_RECORD_COMM,
6266 .misc = exec ? PERF_RECORD_MISC_COMM_EXEC : 0,
6274 perf_event_comm_event(&comm_event);
6281 struct perf_mmap_event {
6282 struct vm_area_struct *vma;
6284 const char *file_name;
6292 struct perf_event_header header;
6302 static int perf_event_mmap_match(struct perf_event *event,
6305 struct perf_mmap_event *mmap_event = data;
6306 struct vm_area_struct *vma = mmap_event->vma;
6307 int executable = vma->vm_flags & VM_EXEC;
6309 return (!executable && event->attr.mmap_data) ||
6310 (executable && (event->attr.mmap || event->attr.mmap2));
6313 static void perf_event_mmap_output(struct perf_event *event,
6316 struct perf_mmap_event *mmap_event = data;
6317 struct perf_output_handle handle;
6318 struct perf_sample_data sample;
6319 int size = mmap_event->event_id.header.size;
6322 if (!perf_event_mmap_match(event, data))
6325 if (event->attr.mmap2) {
6326 mmap_event->event_id.header.type = PERF_RECORD_MMAP2;
6327 mmap_event->event_id.header.size += sizeof(mmap_event->maj);
6328 mmap_event->event_id.header.size += sizeof(mmap_event->min);
6329 mmap_event->event_id.header.size += sizeof(mmap_event->ino);
6330 mmap_event->event_id.header.size += sizeof(mmap_event->ino_generation);
6331 mmap_event->event_id.header.size += sizeof(mmap_event->prot);
6332 mmap_event->event_id.header.size += sizeof(mmap_event->flags);
6335 perf_event_header__init_id(&mmap_event->event_id.header, &sample, event);
6336 ret = perf_output_begin(&handle, event,
6337 mmap_event->event_id.header.size);
6341 mmap_event->event_id.pid = perf_event_pid(event, current);
6342 mmap_event->event_id.tid = perf_event_tid(event, current);
6344 perf_output_put(&handle, mmap_event->event_id);
6346 if (event->attr.mmap2) {
6347 perf_output_put(&handle, mmap_event->maj);
6348 perf_output_put(&handle, mmap_event->min);
6349 perf_output_put(&handle, mmap_event->ino);
6350 perf_output_put(&handle, mmap_event->ino_generation);
6351 perf_output_put(&handle, mmap_event->prot);
6352 perf_output_put(&handle, mmap_event->flags);
6355 __output_copy(&handle, mmap_event->file_name,
6356 mmap_event->file_size);
6358 perf_event__output_id_sample(event, &handle, &sample);
6360 perf_output_end(&handle);
6362 mmap_event->event_id.header.size = size;
6365 static void perf_event_mmap_event(struct perf_mmap_event *mmap_event)
6367 struct vm_area_struct *vma = mmap_event->vma;
6368 struct file *file = vma->vm_file;
6369 int maj = 0, min = 0;
6370 u64 ino = 0, gen = 0;
6371 u32 prot = 0, flags = 0;
6378 struct inode *inode;
6381 buf = kmalloc(PATH_MAX, GFP_KERNEL);
6387 * d_path() works from the end of the rb backwards, so we
6388 * need to add enough zero bytes after the string to handle
6389 * the 64bit alignment we do later.
6391 name = file_path(file, buf, PATH_MAX - sizeof(u64));
6396 inode = file_inode(vma->vm_file);
6397 dev = inode->i_sb->s_dev;
6399 gen = inode->i_generation;
6403 if (vma->vm_flags & VM_READ)
6405 if (vma->vm_flags & VM_WRITE)
6407 if (vma->vm_flags & VM_EXEC)
6410 if (vma->vm_flags & VM_MAYSHARE)
6413 flags = MAP_PRIVATE;
6415 if (vma->vm_flags & VM_DENYWRITE)
6416 flags |= MAP_DENYWRITE;
6417 if (vma->vm_flags & VM_MAYEXEC)
6418 flags |= MAP_EXECUTABLE;
6419 if (vma->vm_flags & VM_LOCKED)
6420 flags |= MAP_LOCKED;
6421 if (vma->vm_flags & VM_HUGETLB)
6422 flags |= MAP_HUGETLB;
6426 if (vma->vm_ops && vma->vm_ops->name) {
6427 name = (char *) vma->vm_ops->name(vma);
6432 name = (char *)arch_vma_name(vma);
6436 if (vma->vm_start <= vma->vm_mm->start_brk &&
6437 vma->vm_end >= vma->vm_mm->brk) {
6441 if (vma->vm_start <= vma->vm_mm->start_stack &&
6442 vma->vm_end >= vma->vm_mm->start_stack) {
6452 strlcpy(tmp, name, sizeof(tmp));
6456 * Since our buffer works in 8 byte units we need to align our string
6457 * size to a multiple of 8. However, we must guarantee the tail end is
6458 * zero'd out to avoid leaking random bits to userspace.
6460 size = strlen(name)+1;
6461 while (!IS_ALIGNED(size, sizeof(u64)))
6462 name[size++] = '\0';
6464 mmap_event->file_name = name;
6465 mmap_event->file_size = size;
6466 mmap_event->maj = maj;
6467 mmap_event->min = min;
6468 mmap_event->ino = ino;
6469 mmap_event->ino_generation = gen;
6470 mmap_event->prot = prot;
6471 mmap_event->flags = flags;
6473 if (!(vma->vm_flags & VM_EXEC))
6474 mmap_event->event_id.header.misc |= PERF_RECORD_MISC_MMAP_DATA;
6476 mmap_event->event_id.header.size = sizeof(mmap_event->event_id) + size;
6478 perf_event_aux(perf_event_mmap_output,
6486 * Whether this @filter depends on a dynamic object which is not loaded
6487 * yet or its load addresses are not known.
6489 static bool perf_addr_filter_needs_mmap(struct perf_addr_filter *filter)
6491 return filter->filter && filter->inode;
6495 * Check whether inode and address range match filter criteria.
6497 static bool perf_addr_filter_match(struct perf_addr_filter *filter,
6498 struct file *file, unsigned long offset,
6501 if (filter->inode != file->f_inode)
6504 if (filter->offset > offset + size)
6507 if (filter->offset + filter->size < offset)
6513 static void __perf_addr_filters_adjust(struct perf_event *event, void *data)
6515 struct perf_addr_filters_head *ifh = perf_event_addr_filters(event);
6516 struct vm_area_struct *vma = data;
6517 unsigned long off = vma->vm_pgoff << PAGE_SHIFT, flags;
6518 struct file *file = vma->vm_file;
6519 struct perf_addr_filter *filter;
6520 unsigned int restart = 0, count = 0;
6522 if (!has_addr_filter(event))
6528 raw_spin_lock_irqsave(&ifh->lock, flags);
6529 list_for_each_entry(filter, &ifh->list, entry) {
6530 if (perf_addr_filter_match(filter, file, off,
6531 vma->vm_end - vma->vm_start)) {
6532 event->addr_filters_offs[count] = vma->vm_start;
6540 event->addr_filters_gen++;
6541 raw_spin_unlock_irqrestore(&ifh->lock, flags);
6544 perf_event_restart(event);
6548 * Adjust all task's events' filters to the new vma
6550 static void perf_addr_filters_adjust(struct vm_area_struct *vma)
6552 struct perf_event_context *ctx;
6556 for_each_task_context_nr(ctxn) {
6557 ctx = rcu_dereference(current->perf_event_ctxp[ctxn]);
6561 perf_event_aux_ctx(ctx, __perf_addr_filters_adjust, vma, true);
6566 void perf_event_mmap(struct vm_area_struct *vma)
6568 struct perf_mmap_event mmap_event;
6570 if (!atomic_read(&nr_mmap_events))
6573 mmap_event = (struct perf_mmap_event){
6579 .type = PERF_RECORD_MMAP,
6580 .misc = PERF_RECORD_MISC_USER,
6585 .start = vma->vm_start,
6586 .len = vma->vm_end - vma->vm_start,
6587 .pgoff = (u64)vma->vm_pgoff << PAGE_SHIFT,
6589 /* .maj (attr_mmap2 only) */
6590 /* .min (attr_mmap2 only) */
6591 /* .ino (attr_mmap2 only) */
6592 /* .ino_generation (attr_mmap2 only) */
6593 /* .prot (attr_mmap2 only) */
6594 /* .flags (attr_mmap2 only) */
6597 perf_addr_filters_adjust(vma);
6598 perf_event_mmap_event(&mmap_event);
6601 void perf_event_aux_event(struct perf_event *event, unsigned long head,
6602 unsigned long size, u64 flags)
6604 struct perf_output_handle handle;
6605 struct perf_sample_data sample;
6606 struct perf_aux_event {
6607 struct perf_event_header header;
6613 .type = PERF_RECORD_AUX,
6615 .size = sizeof(rec),
6623 perf_event_header__init_id(&rec.header, &sample, event);
6624 ret = perf_output_begin(&handle, event, rec.header.size);
6629 perf_output_put(&handle, rec);
6630 perf_event__output_id_sample(event, &handle, &sample);
6632 perf_output_end(&handle);
6636 * Lost/dropped samples logging
6638 void perf_log_lost_samples(struct perf_event *event, u64 lost)
6640 struct perf_output_handle handle;
6641 struct perf_sample_data sample;
6645 struct perf_event_header header;
6647 } lost_samples_event = {
6649 .type = PERF_RECORD_LOST_SAMPLES,
6651 .size = sizeof(lost_samples_event),
6656 perf_event_header__init_id(&lost_samples_event.header, &sample, event);
6658 ret = perf_output_begin(&handle, event,
6659 lost_samples_event.header.size);
6663 perf_output_put(&handle, lost_samples_event);
6664 perf_event__output_id_sample(event, &handle, &sample);
6665 perf_output_end(&handle);
6669 * context_switch tracking
6672 struct perf_switch_event {
6673 struct task_struct *task;
6674 struct task_struct *next_prev;
6677 struct perf_event_header header;
6683 static int perf_event_switch_match(struct perf_event *event)
6685 return event->attr.context_switch;
6688 static void perf_event_switch_output(struct perf_event *event, void *data)
6690 struct perf_switch_event *se = data;
6691 struct perf_output_handle handle;
6692 struct perf_sample_data sample;
6695 if (!perf_event_switch_match(event))
6698 /* Only CPU-wide events are allowed to see next/prev pid/tid */
6699 if (event->ctx->task) {
6700 se->event_id.header.type = PERF_RECORD_SWITCH;
6701 se->event_id.header.size = sizeof(se->event_id.header);
6703 se->event_id.header.type = PERF_RECORD_SWITCH_CPU_WIDE;
6704 se->event_id.header.size = sizeof(se->event_id);
6705 se->event_id.next_prev_pid =
6706 perf_event_pid(event, se->next_prev);
6707 se->event_id.next_prev_tid =
6708 perf_event_tid(event, se->next_prev);
6711 perf_event_header__init_id(&se->event_id.header, &sample, event);
6713 ret = perf_output_begin(&handle, event, se->event_id.header.size);
6717 if (event->ctx->task)
6718 perf_output_put(&handle, se->event_id.header);
6720 perf_output_put(&handle, se->event_id);
6722 perf_event__output_id_sample(event, &handle, &sample);
6724 perf_output_end(&handle);
6727 static void perf_event_switch(struct task_struct *task,
6728 struct task_struct *next_prev, bool sched_in)
6730 struct perf_switch_event switch_event;
6732 /* N.B. caller checks nr_switch_events != 0 */
6734 switch_event = (struct perf_switch_event){
6736 .next_prev = next_prev,
6740 .misc = sched_in ? 0 : PERF_RECORD_MISC_SWITCH_OUT,
6743 /* .next_prev_pid */
6744 /* .next_prev_tid */
6748 perf_event_aux(perf_event_switch_output,
6754 * IRQ throttle logging
6757 static void perf_log_throttle(struct perf_event *event, int enable)
6759 struct perf_output_handle handle;
6760 struct perf_sample_data sample;
6764 struct perf_event_header header;
6768 } throttle_event = {
6770 .type = PERF_RECORD_THROTTLE,
6772 .size = sizeof(throttle_event),
6774 .time = perf_event_clock(event),
6775 .id = primary_event_id(event),
6776 .stream_id = event->id,
6780 throttle_event.header.type = PERF_RECORD_UNTHROTTLE;
6782 perf_event_header__init_id(&throttle_event.header, &sample, event);
6784 ret = perf_output_begin(&handle, event,
6785 throttle_event.header.size);
6789 perf_output_put(&handle, throttle_event);
6790 perf_event__output_id_sample(event, &handle, &sample);
6791 perf_output_end(&handle);
6794 static void perf_log_itrace_start(struct perf_event *event)
6796 struct perf_output_handle handle;
6797 struct perf_sample_data sample;
6798 struct perf_aux_event {
6799 struct perf_event_header header;
6806 event = event->parent;
6808 if (!(event->pmu->capabilities & PERF_PMU_CAP_ITRACE) ||
6809 event->hw.itrace_started)
6812 rec.header.type = PERF_RECORD_ITRACE_START;
6813 rec.header.misc = 0;
6814 rec.header.size = sizeof(rec);
6815 rec.pid = perf_event_pid(event, current);
6816 rec.tid = perf_event_tid(event, current);
6818 perf_event_header__init_id(&rec.header, &sample, event);
6819 ret = perf_output_begin(&handle, event, rec.header.size);
6824 perf_output_put(&handle, rec);
6825 perf_event__output_id_sample(event, &handle, &sample);
6827 perf_output_end(&handle);
6831 * Generic event overflow handling, sampling.
6834 static int __perf_event_overflow(struct perf_event *event,
6835 int throttle, struct perf_sample_data *data,
6836 struct pt_regs *regs)
6838 int events = atomic_read(&event->event_limit);
6839 struct hw_perf_event *hwc = &event->hw;
6844 * Non-sampling counters might still use the PMI to fold short
6845 * hardware counters, ignore those.
6847 if (unlikely(!is_sampling_event(event)))
6850 seq = __this_cpu_read(perf_throttled_seq);
6851 if (seq != hwc->interrupts_seq) {
6852 hwc->interrupts_seq = seq;
6853 hwc->interrupts = 1;
6856 if (unlikely(throttle
6857 && hwc->interrupts >= max_samples_per_tick)) {
6858 __this_cpu_inc(perf_throttled_count);
6859 tick_dep_set_cpu(smp_processor_id(), TICK_DEP_BIT_PERF_EVENTS);
6860 hwc->interrupts = MAX_INTERRUPTS;
6861 perf_log_throttle(event, 0);
6866 if (event->attr.freq) {
6867 u64 now = perf_clock();
6868 s64 delta = now - hwc->freq_time_stamp;
6870 hwc->freq_time_stamp = now;
6872 if (delta > 0 && delta < 2*TICK_NSEC)
6873 perf_adjust_period(event, delta, hwc->last_period, true);
6877 * XXX event_limit might not quite work as expected on inherited
6881 event->pending_kill = POLL_IN;
6882 if (events && atomic_dec_and_test(&event->event_limit)) {
6884 event->pending_kill = POLL_HUP;
6885 event->pending_disable = 1;
6886 irq_work_queue(&event->pending);
6889 event->overflow_handler(event, data, regs);
6891 if (*perf_event_fasync(event) && event->pending_kill) {
6892 event->pending_wakeup = 1;
6893 irq_work_queue(&event->pending);
6899 int perf_event_overflow(struct perf_event *event,
6900 struct perf_sample_data *data,
6901 struct pt_regs *regs)
6903 return __perf_event_overflow(event, 1, data, regs);
6907 * Generic software event infrastructure
6910 struct swevent_htable {
6911 struct swevent_hlist *swevent_hlist;
6912 struct mutex hlist_mutex;
6915 /* Recursion avoidance in each contexts */
6916 int recursion[PERF_NR_CONTEXTS];
6919 static DEFINE_PER_CPU(struct swevent_htable, swevent_htable);
6922 * We directly increment event->count and keep a second value in
6923 * event->hw.period_left to count intervals. This period event
6924 * is kept in the range [-sample_period, 0] so that we can use the
6928 u64 perf_swevent_set_period(struct perf_event *event)
6930 struct hw_perf_event *hwc = &event->hw;
6931 u64 period = hwc->last_period;
6935 hwc->last_period = hwc->sample_period;
6938 old = val = local64_read(&hwc->period_left);
6942 nr = div64_u64(period + val, period);
6943 offset = nr * period;
6945 if (local64_cmpxchg(&hwc->period_left, old, val) != old)
6951 static void perf_swevent_overflow(struct perf_event *event, u64 overflow,
6952 struct perf_sample_data *data,
6953 struct pt_regs *regs)
6955 struct hw_perf_event *hwc = &event->hw;
6959 overflow = perf_swevent_set_period(event);
6961 if (hwc->interrupts == MAX_INTERRUPTS)
6964 for (; overflow; overflow--) {
6965 if (__perf_event_overflow(event, throttle,
6968 * We inhibit the overflow from happening when
6969 * hwc->interrupts == MAX_INTERRUPTS.
6977 static void perf_swevent_event(struct perf_event *event, u64 nr,
6978 struct perf_sample_data *data,
6979 struct pt_regs *regs)
6981 struct hw_perf_event *hwc = &event->hw;
6983 local64_add(nr, &event->count);
6988 if (!is_sampling_event(event))
6991 if ((event->attr.sample_type & PERF_SAMPLE_PERIOD) && !event->attr.freq) {
6993 return perf_swevent_overflow(event, 1, data, regs);
6995 data->period = event->hw.last_period;
6997 if (nr == 1 && hwc->sample_period == 1 && !event->attr.freq)
6998 return perf_swevent_overflow(event, 1, data, regs);
7000 if (local64_add_negative(nr, &hwc->period_left))
7003 perf_swevent_overflow(event, 0, data, regs);
7006 static int perf_exclude_event(struct perf_event *event,
7007 struct pt_regs *regs)
7009 if (event->hw.state & PERF_HES_STOPPED)
7013 if (event->attr.exclude_user && user_mode(regs))
7016 if (event->attr.exclude_kernel && !user_mode(regs))
7023 static int perf_swevent_match(struct perf_event *event,
7024 enum perf_type_id type,
7026 struct perf_sample_data *data,
7027 struct pt_regs *regs)
7029 if (event->attr.type != type)
7032 if (event->attr.config != event_id)
7035 if (perf_exclude_event(event, regs))
7041 static inline u64 swevent_hash(u64 type, u32 event_id)
7043 u64 val = event_id | (type << 32);
7045 return hash_64(val, SWEVENT_HLIST_BITS);
7048 static inline struct hlist_head *
7049 __find_swevent_head(struct swevent_hlist *hlist, u64 type, u32 event_id)
7051 u64 hash = swevent_hash(type, event_id);
7053 return &hlist->heads[hash];
7056 /* For the read side: events when they trigger */
7057 static inline struct hlist_head *
7058 find_swevent_head_rcu(struct swevent_htable *swhash, u64 type, u32 event_id)
7060 struct swevent_hlist *hlist;
7062 hlist = rcu_dereference(swhash->swevent_hlist);
7066 return __find_swevent_head(hlist, type, event_id);
7069 /* For the event head insertion and removal in the hlist */
7070 static inline struct hlist_head *
7071 find_swevent_head(struct swevent_htable *swhash, struct perf_event *event)
7073 struct swevent_hlist *hlist;
7074 u32 event_id = event->attr.config;
7075 u64 type = event->attr.type;
7078 * Event scheduling is always serialized against hlist allocation
7079 * and release. Which makes the protected version suitable here.
7080 * The context lock guarantees that.
7082 hlist = rcu_dereference_protected(swhash->swevent_hlist,
7083 lockdep_is_held(&event->ctx->lock));
7087 return __find_swevent_head(hlist, type, event_id);
7090 static void do_perf_sw_event(enum perf_type_id type, u32 event_id,
7092 struct perf_sample_data *data,
7093 struct pt_regs *regs)
7095 struct swevent_htable *swhash = this_cpu_ptr(&swevent_htable);
7096 struct perf_event *event;
7097 struct hlist_head *head;
7100 head = find_swevent_head_rcu(swhash, type, event_id);
7104 hlist_for_each_entry_rcu(event, head, hlist_entry) {
7105 if (perf_swevent_match(event, type, event_id, data, regs))
7106 perf_swevent_event(event, nr, data, regs);
7112 DEFINE_PER_CPU(struct pt_regs, __perf_regs[4]);
7114 int perf_swevent_get_recursion_context(void)
7116 struct swevent_htable *swhash = this_cpu_ptr(&swevent_htable);
7118 return get_recursion_context(swhash->recursion);
7120 EXPORT_SYMBOL_GPL(perf_swevent_get_recursion_context);
7122 void perf_swevent_put_recursion_context(int rctx)
7124 struct swevent_htable *swhash = this_cpu_ptr(&swevent_htable);
7126 put_recursion_context(swhash->recursion, rctx);
7129 void ___perf_sw_event(u32 event_id, u64 nr, struct pt_regs *regs, u64 addr)
7131 struct perf_sample_data data;
7133 if (WARN_ON_ONCE(!regs))
7136 perf_sample_data_init(&data, addr, 0);
7137 do_perf_sw_event(PERF_TYPE_SOFTWARE, event_id, nr, &data, regs);
7140 void __perf_sw_event(u32 event_id, u64 nr, struct pt_regs *regs, u64 addr)
7144 preempt_disable_notrace();
7145 rctx = perf_swevent_get_recursion_context();
7146 if (unlikely(rctx < 0))
7149 ___perf_sw_event(event_id, nr, regs, addr);
7151 perf_swevent_put_recursion_context(rctx);
7153 preempt_enable_notrace();
7156 static void perf_swevent_read(struct perf_event *event)
7160 static int perf_swevent_add(struct perf_event *event, int flags)
7162 struct swevent_htable *swhash = this_cpu_ptr(&swevent_htable);
7163 struct hw_perf_event *hwc = &event->hw;
7164 struct hlist_head *head;
7166 if (is_sampling_event(event)) {
7167 hwc->last_period = hwc->sample_period;
7168 perf_swevent_set_period(event);
7171 hwc->state = !(flags & PERF_EF_START);
7173 head = find_swevent_head(swhash, event);
7174 if (WARN_ON_ONCE(!head))
7177 hlist_add_head_rcu(&event->hlist_entry, head);
7178 perf_event_update_userpage(event);
7183 static void perf_swevent_del(struct perf_event *event, int flags)
7185 hlist_del_rcu(&event->hlist_entry);
7188 static void perf_swevent_start(struct perf_event *event, int flags)
7190 event->hw.state = 0;
7193 static void perf_swevent_stop(struct perf_event *event, int flags)
7195 event->hw.state = PERF_HES_STOPPED;
7198 /* Deref the hlist from the update side */
7199 static inline struct swevent_hlist *
7200 swevent_hlist_deref(struct swevent_htable *swhash)
7202 return rcu_dereference_protected(swhash->swevent_hlist,
7203 lockdep_is_held(&swhash->hlist_mutex));
7206 static void swevent_hlist_release(struct swevent_htable *swhash)
7208 struct swevent_hlist *hlist = swevent_hlist_deref(swhash);
7213 RCU_INIT_POINTER(swhash->swevent_hlist, NULL);
7214 kfree_rcu(hlist, rcu_head);
7217 static void swevent_hlist_put_cpu(int cpu)
7219 struct swevent_htable *swhash = &per_cpu(swevent_htable, cpu);
7221 mutex_lock(&swhash->hlist_mutex);
7223 if (!--swhash->hlist_refcount)
7224 swevent_hlist_release(swhash);
7226 mutex_unlock(&swhash->hlist_mutex);
7229 static void swevent_hlist_put(void)
7233 for_each_possible_cpu(cpu)
7234 swevent_hlist_put_cpu(cpu);
7237 static int swevent_hlist_get_cpu(int cpu)
7239 struct swevent_htable *swhash = &per_cpu(swevent_htable, cpu);
7242 mutex_lock(&swhash->hlist_mutex);
7243 if (!swevent_hlist_deref(swhash) && cpu_online(cpu)) {
7244 struct swevent_hlist *hlist;
7246 hlist = kzalloc(sizeof(*hlist), GFP_KERNEL);
7251 rcu_assign_pointer(swhash->swevent_hlist, hlist);
7253 swhash->hlist_refcount++;
7255 mutex_unlock(&swhash->hlist_mutex);
7260 static int swevent_hlist_get(void)
7262 int err, cpu, failed_cpu;
7265 for_each_possible_cpu(cpu) {
7266 err = swevent_hlist_get_cpu(cpu);
7276 for_each_possible_cpu(cpu) {
7277 if (cpu == failed_cpu)
7279 swevent_hlist_put_cpu(cpu);
7286 struct static_key perf_swevent_enabled[PERF_COUNT_SW_MAX];
7288 static void sw_perf_event_destroy(struct perf_event *event)
7290 u64 event_id = event->attr.config;
7292 WARN_ON(event->parent);
7294 static_key_slow_dec(&perf_swevent_enabled[event_id]);
7295 swevent_hlist_put();
7298 static int perf_swevent_init(struct perf_event *event)
7300 u64 event_id = event->attr.config;
7302 if (event->attr.type != PERF_TYPE_SOFTWARE)
7306 * no branch sampling for software events
7308 if (has_branch_stack(event))
7312 case PERF_COUNT_SW_CPU_CLOCK:
7313 case PERF_COUNT_SW_TASK_CLOCK:
7320 if (event_id >= PERF_COUNT_SW_MAX)
7323 if (!event->parent) {
7326 err = swevent_hlist_get();
7330 static_key_slow_inc(&perf_swevent_enabled[event_id]);
7331 event->destroy = sw_perf_event_destroy;
7337 static struct pmu perf_swevent = {
7338 .task_ctx_nr = perf_sw_context,
7340 .capabilities = PERF_PMU_CAP_NO_NMI,
7342 .event_init = perf_swevent_init,
7343 .add = perf_swevent_add,
7344 .del = perf_swevent_del,
7345 .start = perf_swevent_start,
7346 .stop = perf_swevent_stop,
7347 .read = perf_swevent_read,
7350 #ifdef CONFIG_EVENT_TRACING
7352 static int perf_tp_filter_match(struct perf_event *event,
7353 struct perf_sample_data *data)
7355 void *record = data->raw->data;
7357 /* only top level events have filters set */
7359 event = event->parent;
7361 if (likely(!event->filter) || filter_match_preds(event->filter, record))
7366 static int perf_tp_event_match(struct perf_event *event,
7367 struct perf_sample_data *data,
7368 struct pt_regs *regs)
7370 if (event->hw.state & PERF_HES_STOPPED)
7373 * All tracepoints are from kernel-space.
7375 if (event->attr.exclude_kernel)
7378 if (!perf_tp_filter_match(event, data))
7384 void perf_trace_run_bpf_submit(void *raw_data, int size, int rctx,
7385 struct trace_event_call *call, u64 count,
7386 struct pt_regs *regs, struct hlist_head *head,
7387 struct task_struct *task)
7389 struct bpf_prog *prog = call->prog;
7392 *(struct pt_regs **)raw_data = regs;
7393 if (!trace_call_bpf(prog, raw_data) || hlist_empty(head)) {
7394 perf_swevent_put_recursion_context(rctx);
7398 perf_tp_event(call->event.type, count, raw_data, size, regs, head,
7401 EXPORT_SYMBOL_GPL(perf_trace_run_bpf_submit);
7403 void perf_tp_event(u16 event_type, u64 count, void *record, int entry_size,
7404 struct pt_regs *regs, struct hlist_head *head, int rctx,
7405 struct task_struct *task)
7407 struct perf_sample_data data;
7408 struct perf_event *event;
7410 struct perf_raw_record raw = {
7415 perf_sample_data_init(&data, 0, 0);
7418 perf_trace_buf_update(record, event_type);
7420 hlist_for_each_entry_rcu(event, head, hlist_entry) {
7421 if (perf_tp_event_match(event, &data, regs))
7422 perf_swevent_event(event, count, &data, regs);
7426 * If we got specified a target task, also iterate its context and
7427 * deliver this event there too.
7429 if (task && task != current) {
7430 struct perf_event_context *ctx;
7431 struct trace_entry *entry = record;
7434 ctx = rcu_dereference(task->perf_event_ctxp[perf_sw_context]);
7438 list_for_each_entry_rcu(event, &ctx->event_list, event_entry) {
7439 if (event->attr.type != PERF_TYPE_TRACEPOINT)
7441 if (event->attr.config != entry->type)
7443 if (perf_tp_event_match(event, &data, regs))
7444 perf_swevent_event(event, count, &data, regs);
7450 perf_swevent_put_recursion_context(rctx);
7452 EXPORT_SYMBOL_GPL(perf_tp_event);
7454 static void tp_perf_event_destroy(struct perf_event *event)
7456 perf_trace_destroy(event);
7459 static int perf_tp_event_init(struct perf_event *event)
7463 if (event->attr.type != PERF_TYPE_TRACEPOINT)
7467 * no branch sampling for tracepoint events
7469 if (has_branch_stack(event))
7472 err = perf_trace_init(event);
7476 event->destroy = tp_perf_event_destroy;
7481 static struct pmu perf_tracepoint = {
7482 .task_ctx_nr = perf_sw_context,
7484 .event_init = perf_tp_event_init,
7485 .add = perf_trace_add,
7486 .del = perf_trace_del,
7487 .start = perf_swevent_start,
7488 .stop = perf_swevent_stop,
7489 .read = perf_swevent_read,
7492 static inline void perf_tp_register(void)
7494 perf_pmu_register(&perf_tracepoint, "tracepoint", PERF_TYPE_TRACEPOINT);
7497 static void perf_event_free_filter(struct perf_event *event)
7499 ftrace_profile_free_filter(event);
7502 static int perf_event_set_bpf_prog(struct perf_event *event, u32 prog_fd)
7504 bool is_kprobe, is_tracepoint;
7505 struct bpf_prog *prog;
7507 if (event->attr.type != PERF_TYPE_TRACEPOINT)
7510 if (event->tp_event->prog)
7513 is_kprobe = event->tp_event->flags & TRACE_EVENT_FL_UKPROBE;
7514 is_tracepoint = event->tp_event->flags & TRACE_EVENT_FL_TRACEPOINT;
7515 if (!is_kprobe && !is_tracepoint)
7516 /* bpf programs can only be attached to u/kprobe or tracepoint */
7519 prog = bpf_prog_get(prog_fd);
7521 return PTR_ERR(prog);
7523 if ((is_kprobe && prog->type != BPF_PROG_TYPE_KPROBE) ||
7524 (is_tracepoint && prog->type != BPF_PROG_TYPE_TRACEPOINT)) {
7525 /* valid fd, but invalid bpf program type */
7530 if (is_tracepoint) {
7531 int off = trace_event_get_offsets(event->tp_event);
7533 if (prog->aux->max_ctx_offset > off) {
7538 event->tp_event->prog = prog;
7543 static void perf_event_free_bpf_prog(struct perf_event *event)
7545 struct bpf_prog *prog;
7547 if (!event->tp_event)
7550 prog = event->tp_event->prog;
7552 event->tp_event->prog = NULL;
7553 bpf_prog_put_rcu(prog);
7559 static inline void perf_tp_register(void)
7563 static void perf_event_free_filter(struct perf_event *event)
7567 static int perf_event_set_bpf_prog(struct perf_event *event, u32 prog_fd)
7572 static void perf_event_free_bpf_prog(struct perf_event *event)
7575 #endif /* CONFIG_EVENT_TRACING */
7577 #ifdef CONFIG_HAVE_HW_BREAKPOINT
7578 void perf_bp_event(struct perf_event *bp, void *data)
7580 struct perf_sample_data sample;
7581 struct pt_regs *regs = data;
7583 perf_sample_data_init(&sample, bp->attr.bp_addr, 0);
7585 if (!bp->hw.state && !perf_exclude_event(bp, regs))
7586 perf_swevent_event(bp, 1, &sample, regs);
7591 * Allocate a new address filter
7593 static struct perf_addr_filter *
7594 perf_addr_filter_new(struct perf_event *event, struct list_head *filters)
7596 int node = cpu_to_node(event->cpu == -1 ? 0 : event->cpu);
7597 struct perf_addr_filter *filter;
7599 filter = kzalloc_node(sizeof(*filter), GFP_KERNEL, node);
7603 INIT_LIST_HEAD(&filter->entry);
7604 list_add_tail(&filter->entry, filters);
7609 static void free_filters_list(struct list_head *filters)
7611 struct perf_addr_filter *filter, *iter;
7613 list_for_each_entry_safe(filter, iter, filters, entry) {
7615 iput(filter->inode);
7616 list_del(&filter->entry);
7622 * Free existing address filters and optionally install new ones
7624 static void perf_addr_filters_splice(struct perf_event *event,
7625 struct list_head *head)
7627 unsigned long flags;
7630 if (!has_addr_filter(event))
7633 /* don't bother with children, they don't have their own filters */
7637 raw_spin_lock_irqsave(&event->addr_filters.lock, flags);
7639 list_splice_init(&event->addr_filters.list, &list);
7641 list_splice(head, &event->addr_filters.list);
7643 raw_spin_unlock_irqrestore(&event->addr_filters.lock, flags);
7645 free_filters_list(&list);
7649 * Scan through mm's vmas and see if one of them matches the
7650 * @filter; if so, adjust filter's address range.
7651 * Called with mm::mmap_sem down for reading.
7653 static unsigned long perf_addr_filter_apply(struct perf_addr_filter *filter,
7654 struct mm_struct *mm)
7656 struct vm_area_struct *vma;
7658 for (vma = mm->mmap; vma; vma = vma->vm_next) {
7659 struct file *file = vma->vm_file;
7660 unsigned long off = vma->vm_pgoff << PAGE_SHIFT;
7661 unsigned long vma_size = vma->vm_end - vma->vm_start;
7666 if (!perf_addr_filter_match(filter, file, off, vma_size))
7669 return vma->vm_start;
7676 * Update event's address range filters based on the
7677 * task's existing mappings, if any.
7679 static void perf_event_addr_filters_apply(struct perf_event *event)
7681 struct perf_addr_filters_head *ifh = perf_event_addr_filters(event);
7682 struct task_struct *task = READ_ONCE(event->ctx->task);
7683 struct perf_addr_filter *filter;
7684 struct mm_struct *mm = NULL;
7685 unsigned int count = 0;
7686 unsigned long flags;
7689 * We may observe TASK_TOMBSTONE, which means that the event tear-down
7690 * will stop on the parent's child_mutex that our caller is also holding
7692 if (task == TASK_TOMBSTONE)
7695 mm = get_task_mm(event->ctx->task);
7699 down_read(&mm->mmap_sem);
7701 raw_spin_lock_irqsave(&ifh->lock, flags);
7702 list_for_each_entry(filter, &ifh->list, entry) {
7703 event->addr_filters_offs[count] = 0;
7705 if (perf_addr_filter_needs_mmap(filter))
7706 event->addr_filters_offs[count] =
7707 perf_addr_filter_apply(filter, mm);
7712 event->addr_filters_gen++;
7713 raw_spin_unlock_irqrestore(&ifh->lock, flags);
7715 up_read(&mm->mmap_sem);
7720 perf_event_restart(event);
7724 * Address range filtering: limiting the data to certain
7725 * instruction address ranges. Filters are ioctl()ed to us from
7726 * userspace as ascii strings.
7728 * Filter string format:
7731 * where ACTION is one of the
7732 * * "filter": limit the trace to this region
7733 * * "start": start tracing from this address
7734 * * "stop": stop tracing at this address/region;
7736 * * for kernel addresses: <start address>[/<size>]
7737 * * for object files: <start address>[/<size>]@</path/to/object/file>
7739 * if <size> is not specified, the range is treated as a single address.
7752 IF_STATE_ACTION = 0,
7757 static const match_table_t if_tokens = {
7758 { IF_ACT_FILTER, "filter" },
7759 { IF_ACT_START, "start" },
7760 { IF_ACT_STOP, "stop" },
7761 { IF_SRC_FILE, "%u/%u@%s" },
7762 { IF_SRC_KERNEL, "%u/%u" },
7763 { IF_SRC_FILEADDR, "%u@%s" },
7764 { IF_SRC_KERNELADDR, "%u" },
7768 * Address filter string parser
7771 perf_event_parse_addr_filter(struct perf_event *event, char *fstr,
7772 struct list_head *filters)
7774 struct perf_addr_filter *filter = NULL;
7775 char *start, *orig, *filename = NULL;
7777 substring_t args[MAX_OPT_ARGS];
7778 int state = IF_STATE_ACTION, token;
7779 unsigned int kernel = 0;
7782 orig = fstr = kstrdup(fstr, GFP_KERNEL);
7786 while ((start = strsep(&fstr, " ,\n")) != NULL) {
7792 /* filter definition begins */
7793 if (state == IF_STATE_ACTION) {
7794 filter = perf_addr_filter_new(event, filters);
7799 token = match_token(start, if_tokens, args);
7806 if (state != IF_STATE_ACTION)
7809 state = IF_STATE_SOURCE;
7812 case IF_SRC_KERNELADDR:
7816 case IF_SRC_FILEADDR:
7818 if (state != IF_STATE_SOURCE)
7821 if (token == IF_SRC_FILE || token == IF_SRC_KERNEL)
7825 ret = kstrtoul(args[0].from, 0, &filter->offset);
7829 if (filter->range) {
7831 ret = kstrtoul(args[1].from, 0, &filter->size);
7836 if (token == IF_SRC_FILE) {
7837 filename = match_strdup(&args[2]);
7844 state = IF_STATE_END;
7852 * Filter definition is fully parsed, validate and install it.
7853 * Make sure that it doesn't contradict itself or the event's
7856 if (state == IF_STATE_END) {
7857 if (kernel && event->attr.exclude_kernel)
7864 /* look up the path and grab its inode */
7865 ret = kern_path(filename, LOOKUP_FOLLOW, &path);
7867 goto fail_free_name;
7869 filter->inode = igrab(d_inode(path.dentry));
7875 if (!filter->inode ||
7876 !S_ISREG(filter->inode->i_mode))
7877 /* free_filters_list() will iput() */
7881 /* ready to consume more filters */
7882 state = IF_STATE_ACTION;
7887 if (state != IF_STATE_ACTION)
7897 free_filters_list(filters);
7904 perf_event_set_addr_filter(struct perf_event *event, char *filter_str)
7910 * Since this is called in perf_ioctl() path, we're already holding
7913 lockdep_assert_held(&event->ctx->mutex);
7915 if (WARN_ON_ONCE(event->parent))
7919 * For now, we only support filtering in per-task events; doing so
7920 * for CPU-wide events requires additional context switching trickery,
7921 * since same object code will be mapped at different virtual
7922 * addresses in different processes.
7924 if (!event->ctx->task)
7927 ret = perf_event_parse_addr_filter(event, filter_str, &filters);
7931 ret = event->pmu->addr_filters_validate(&filters);
7933 free_filters_list(&filters);
7937 /* remove existing filters, if any */
7938 perf_addr_filters_splice(event, &filters);
7940 /* install new filters */
7941 perf_event_for_each_child(event, perf_event_addr_filters_apply);
7946 static int perf_event_set_filter(struct perf_event *event, void __user *arg)
7951 if ((event->attr.type != PERF_TYPE_TRACEPOINT ||
7952 !IS_ENABLED(CONFIG_EVENT_TRACING)) &&
7953 !has_addr_filter(event))
7956 filter_str = strndup_user(arg, PAGE_SIZE);
7957 if (IS_ERR(filter_str))
7958 return PTR_ERR(filter_str);
7960 if (IS_ENABLED(CONFIG_EVENT_TRACING) &&
7961 event->attr.type == PERF_TYPE_TRACEPOINT)
7962 ret = ftrace_profile_set_filter(event, event->attr.config,
7964 else if (has_addr_filter(event))
7965 ret = perf_event_set_addr_filter(event, filter_str);
7972 * hrtimer based swevent callback
7975 static enum hrtimer_restart perf_swevent_hrtimer(struct hrtimer *hrtimer)
7977 enum hrtimer_restart ret = HRTIMER_RESTART;
7978 struct perf_sample_data data;
7979 struct pt_regs *regs;
7980 struct perf_event *event;
7983 event = container_of(hrtimer, struct perf_event, hw.hrtimer);
7985 if (event->state != PERF_EVENT_STATE_ACTIVE)
7986 return HRTIMER_NORESTART;
7988 event->pmu->read(event);
7990 perf_sample_data_init(&data, 0, event->hw.last_period);
7991 regs = get_irq_regs();
7993 if (regs && !perf_exclude_event(event, regs)) {
7994 if (!(event->attr.exclude_idle && is_idle_task(current)))
7995 if (__perf_event_overflow(event, 1, &data, regs))
7996 ret = HRTIMER_NORESTART;
7999 period = max_t(u64, 10000, event->hw.sample_period);
8000 hrtimer_forward_now(hrtimer, ns_to_ktime(period));
8005 static void perf_swevent_start_hrtimer(struct perf_event *event)
8007 struct hw_perf_event *hwc = &event->hw;
8010 if (!is_sampling_event(event))
8013 period = local64_read(&hwc->period_left);
8018 local64_set(&hwc->period_left, 0);
8020 period = max_t(u64, 10000, hwc->sample_period);
8022 hrtimer_start(&hwc->hrtimer, ns_to_ktime(period),
8023 HRTIMER_MODE_REL_PINNED);
8026 static void perf_swevent_cancel_hrtimer(struct perf_event *event)
8028 struct hw_perf_event *hwc = &event->hw;
8030 if (is_sampling_event(event)) {
8031 ktime_t remaining = hrtimer_get_remaining(&hwc->hrtimer);
8032 local64_set(&hwc->period_left, ktime_to_ns(remaining));
8034 hrtimer_cancel(&hwc->hrtimer);
8038 static void perf_swevent_init_hrtimer(struct perf_event *event)
8040 struct hw_perf_event *hwc = &event->hw;
8042 if (!is_sampling_event(event))
8045 hrtimer_init(&hwc->hrtimer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
8046 hwc->hrtimer.function = perf_swevent_hrtimer;
8049 * Since hrtimers have a fixed rate, we can do a static freq->period
8050 * mapping and avoid the whole period adjust feedback stuff.
8052 if (event->attr.freq) {
8053 long freq = event->attr.sample_freq;
8055 event->attr.sample_period = NSEC_PER_SEC / freq;
8056 hwc->sample_period = event->attr.sample_period;
8057 local64_set(&hwc->period_left, hwc->sample_period);
8058 hwc->last_period = hwc->sample_period;
8059 event->attr.freq = 0;
8064 * Software event: cpu wall time clock
8067 static void cpu_clock_event_update(struct perf_event *event)
8072 now = local_clock();
8073 prev = local64_xchg(&event->hw.prev_count, now);
8074 local64_add(now - prev, &event->count);
8077 static void cpu_clock_event_start(struct perf_event *event, int flags)
8079 local64_set(&event->hw.prev_count, local_clock());
8080 perf_swevent_start_hrtimer(event);
8083 static void cpu_clock_event_stop(struct perf_event *event, int flags)
8085 perf_swevent_cancel_hrtimer(event);
8086 cpu_clock_event_update(event);
8089 static int cpu_clock_event_add(struct perf_event *event, int flags)
8091 if (flags & PERF_EF_START)
8092 cpu_clock_event_start(event, flags);
8093 perf_event_update_userpage(event);
8098 static void cpu_clock_event_del(struct perf_event *event, int flags)
8100 cpu_clock_event_stop(event, flags);
8103 static void cpu_clock_event_read(struct perf_event *event)
8105 cpu_clock_event_update(event);
8108 static int cpu_clock_event_init(struct perf_event *event)
8110 if (event->attr.type != PERF_TYPE_SOFTWARE)
8113 if (event->attr.config != PERF_COUNT_SW_CPU_CLOCK)
8117 * no branch sampling for software events
8119 if (has_branch_stack(event))
8122 perf_swevent_init_hrtimer(event);
8127 static struct pmu perf_cpu_clock = {
8128 .task_ctx_nr = perf_sw_context,
8130 .capabilities = PERF_PMU_CAP_NO_NMI,
8132 .event_init = cpu_clock_event_init,
8133 .add = cpu_clock_event_add,
8134 .del = cpu_clock_event_del,
8135 .start = cpu_clock_event_start,
8136 .stop = cpu_clock_event_stop,
8137 .read = cpu_clock_event_read,
8141 * Software event: task time clock
8144 static void task_clock_event_update(struct perf_event *event, u64 now)
8149 prev = local64_xchg(&event->hw.prev_count, now);
8151 local64_add(delta, &event->count);
8154 static void task_clock_event_start(struct perf_event *event, int flags)
8156 local64_set(&event->hw.prev_count, event->ctx->time);
8157 perf_swevent_start_hrtimer(event);
8160 static void task_clock_event_stop(struct perf_event *event, int flags)
8162 perf_swevent_cancel_hrtimer(event);
8163 task_clock_event_update(event, event->ctx->time);
8166 static int task_clock_event_add(struct perf_event *event, int flags)
8168 if (flags & PERF_EF_START)
8169 task_clock_event_start(event, flags);
8170 perf_event_update_userpage(event);
8175 static void task_clock_event_del(struct perf_event *event, int flags)
8177 task_clock_event_stop(event, PERF_EF_UPDATE);
8180 static void task_clock_event_read(struct perf_event *event)
8182 u64 now = perf_clock();
8183 u64 delta = now - event->ctx->timestamp;
8184 u64 time = event->ctx->time + delta;
8186 task_clock_event_update(event, time);
8189 static int task_clock_event_init(struct perf_event *event)
8191 if (event->attr.type != PERF_TYPE_SOFTWARE)
8194 if (event->attr.config != PERF_COUNT_SW_TASK_CLOCK)
8198 * no branch sampling for software events
8200 if (has_branch_stack(event))
8203 perf_swevent_init_hrtimer(event);
8208 static struct pmu perf_task_clock = {
8209 .task_ctx_nr = perf_sw_context,
8211 .capabilities = PERF_PMU_CAP_NO_NMI,
8213 .event_init = task_clock_event_init,
8214 .add = task_clock_event_add,
8215 .del = task_clock_event_del,
8216 .start = task_clock_event_start,
8217 .stop = task_clock_event_stop,
8218 .read = task_clock_event_read,
8221 static void perf_pmu_nop_void(struct pmu *pmu)
8225 static void perf_pmu_nop_txn(struct pmu *pmu, unsigned int flags)
8229 static int perf_pmu_nop_int(struct pmu *pmu)
8234 static DEFINE_PER_CPU(unsigned int, nop_txn_flags);
8236 static void perf_pmu_start_txn(struct pmu *pmu, unsigned int flags)
8238 __this_cpu_write(nop_txn_flags, flags);
8240 if (flags & ~PERF_PMU_TXN_ADD)
8243 perf_pmu_disable(pmu);
8246 static int perf_pmu_commit_txn(struct pmu *pmu)
8248 unsigned int flags = __this_cpu_read(nop_txn_flags);
8250 __this_cpu_write(nop_txn_flags, 0);
8252 if (flags & ~PERF_PMU_TXN_ADD)
8255 perf_pmu_enable(pmu);
8259 static void perf_pmu_cancel_txn(struct pmu *pmu)
8261 unsigned int flags = __this_cpu_read(nop_txn_flags);
8263 __this_cpu_write(nop_txn_flags, 0);
8265 if (flags & ~PERF_PMU_TXN_ADD)
8268 perf_pmu_enable(pmu);
8271 static int perf_event_idx_default(struct perf_event *event)
8277 * Ensures all contexts with the same task_ctx_nr have the same
8278 * pmu_cpu_context too.
8280 static struct perf_cpu_context __percpu *find_pmu_context(int ctxn)
8287 list_for_each_entry(pmu, &pmus, entry) {
8288 if (pmu->task_ctx_nr == ctxn)
8289 return pmu->pmu_cpu_context;
8295 static void update_pmu_context(struct pmu *pmu, struct pmu *old_pmu)
8299 for_each_possible_cpu(cpu) {
8300 struct perf_cpu_context *cpuctx;
8302 cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
8304 if (cpuctx->unique_pmu == old_pmu)
8305 cpuctx->unique_pmu = pmu;
8309 static void free_pmu_context(struct pmu *pmu)
8313 mutex_lock(&pmus_lock);
8315 * Like a real lame refcount.
8317 list_for_each_entry(i, &pmus, entry) {
8318 if (i->pmu_cpu_context == pmu->pmu_cpu_context) {
8319 update_pmu_context(i, pmu);
8324 free_percpu(pmu->pmu_cpu_context);
8326 mutex_unlock(&pmus_lock);
8330 * Let userspace know that this PMU supports address range filtering:
8332 static ssize_t nr_addr_filters_show(struct device *dev,
8333 struct device_attribute *attr,
8336 struct pmu *pmu = dev_get_drvdata(dev);
8338 return snprintf(page, PAGE_SIZE - 1, "%d\n", pmu->nr_addr_filters);
8340 DEVICE_ATTR_RO(nr_addr_filters);
8342 static struct idr pmu_idr;
8345 type_show(struct device *dev, struct device_attribute *attr, char *page)
8347 struct pmu *pmu = dev_get_drvdata(dev);
8349 return snprintf(page, PAGE_SIZE-1, "%d\n", pmu->type);
8351 static DEVICE_ATTR_RO(type);
8354 perf_event_mux_interval_ms_show(struct device *dev,
8355 struct device_attribute *attr,
8358 struct pmu *pmu = dev_get_drvdata(dev);
8360 return snprintf(page, PAGE_SIZE-1, "%d\n", pmu->hrtimer_interval_ms);
8363 static DEFINE_MUTEX(mux_interval_mutex);
8366 perf_event_mux_interval_ms_store(struct device *dev,
8367 struct device_attribute *attr,
8368 const char *buf, size_t count)
8370 struct pmu *pmu = dev_get_drvdata(dev);
8371 int timer, cpu, ret;
8373 ret = kstrtoint(buf, 0, &timer);
8380 /* same value, noting to do */
8381 if (timer == pmu->hrtimer_interval_ms)
8384 mutex_lock(&mux_interval_mutex);
8385 pmu->hrtimer_interval_ms = timer;
8387 /* update all cpuctx for this PMU */
8389 for_each_online_cpu(cpu) {
8390 struct perf_cpu_context *cpuctx;
8391 cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
8392 cpuctx->hrtimer_interval = ns_to_ktime(NSEC_PER_MSEC * timer);
8394 cpu_function_call(cpu,
8395 (remote_function_f)perf_mux_hrtimer_restart, cpuctx);
8398 mutex_unlock(&mux_interval_mutex);
8402 static DEVICE_ATTR_RW(perf_event_mux_interval_ms);
8404 static struct attribute *pmu_dev_attrs[] = {
8405 &dev_attr_type.attr,
8406 &dev_attr_perf_event_mux_interval_ms.attr,
8409 ATTRIBUTE_GROUPS(pmu_dev);
8411 static int pmu_bus_running;
8412 static struct bus_type pmu_bus = {
8413 .name = "event_source",
8414 .dev_groups = pmu_dev_groups,
8417 static void pmu_dev_release(struct device *dev)
8422 static int pmu_dev_alloc(struct pmu *pmu)
8426 pmu->dev = kzalloc(sizeof(struct device), GFP_KERNEL);
8430 pmu->dev->groups = pmu->attr_groups;
8431 device_initialize(pmu->dev);
8432 ret = dev_set_name(pmu->dev, "%s", pmu->name);
8436 dev_set_drvdata(pmu->dev, pmu);
8437 pmu->dev->bus = &pmu_bus;
8438 pmu->dev->release = pmu_dev_release;
8439 ret = device_add(pmu->dev);
8443 /* For PMUs with address filters, throw in an extra attribute: */
8444 if (pmu->nr_addr_filters)
8445 ret = device_create_file(pmu->dev, &dev_attr_nr_addr_filters);
8454 device_del(pmu->dev);
8457 put_device(pmu->dev);
8461 static struct lock_class_key cpuctx_mutex;
8462 static struct lock_class_key cpuctx_lock;
8464 int perf_pmu_register(struct pmu *pmu, const char *name, int type)
8468 mutex_lock(&pmus_lock);
8470 pmu->pmu_disable_count = alloc_percpu(int);
8471 if (!pmu->pmu_disable_count)
8480 type = idr_alloc(&pmu_idr, pmu, PERF_TYPE_MAX, 0, GFP_KERNEL);
8488 if (pmu_bus_running) {
8489 ret = pmu_dev_alloc(pmu);
8495 if (pmu->task_ctx_nr == perf_hw_context) {
8496 static int hw_context_taken = 0;
8499 * Other than systems with heterogeneous CPUs, it never makes
8500 * sense for two PMUs to share perf_hw_context. PMUs which are
8501 * uncore must use perf_invalid_context.
8503 if (WARN_ON_ONCE(hw_context_taken &&
8504 !(pmu->capabilities & PERF_PMU_CAP_HETEROGENEOUS_CPUS)))
8505 pmu->task_ctx_nr = perf_invalid_context;
8507 hw_context_taken = 1;
8510 pmu->pmu_cpu_context = find_pmu_context(pmu->task_ctx_nr);
8511 if (pmu->pmu_cpu_context)
8512 goto got_cpu_context;
8515 pmu->pmu_cpu_context = alloc_percpu(struct perf_cpu_context);
8516 if (!pmu->pmu_cpu_context)
8519 for_each_possible_cpu(cpu) {
8520 struct perf_cpu_context *cpuctx;
8522 cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
8523 __perf_event_init_context(&cpuctx->ctx);
8524 lockdep_set_class(&cpuctx->ctx.mutex, &cpuctx_mutex);
8525 lockdep_set_class(&cpuctx->ctx.lock, &cpuctx_lock);
8526 cpuctx->ctx.pmu = pmu;
8528 __perf_mux_hrtimer_init(cpuctx, cpu);
8530 cpuctx->unique_pmu = pmu;
8534 if (!pmu->start_txn) {
8535 if (pmu->pmu_enable) {
8537 * If we have pmu_enable/pmu_disable calls, install
8538 * transaction stubs that use that to try and batch
8539 * hardware accesses.
8541 pmu->start_txn = perf_pmu_start_txn;
8542 pmu->commit_txn = perf_pmu_commit_txn;
8543 pmu->cancel_txn = perf_pmu_cancel_txn;
8545 pmu->start_txn = perf_pmu_nop_txn;
8546 pmu->commit_txn = perf_pmu_nop_int;
8547 pmu->cancel_txn = perf_pmu_nop_void;
8551 if (!pmu->pmu_enable) {
8552 pmu->pmu_enable = perf_pmu_nop_void;
8553 pmu->pmu_disable = perf_pmu_nop_void;
8556 if (!pmu->event_idx)
8557 pmu->event_idx = perf_event_idx_default;
8559 list_add_rcu(&pmu->entry, &pmus);
8560 atomic_set(&pmu->exclusive_cnt, 0);
8563 mutex_unlock(&pmus_lock);
8568 device_del(pmu->dev);
8569 put_device(pmu->dev);
8572 if (pmu->type >= PERF_TYPE_MAX)
8573 idr_remove(&pmu_idr, pmu->type);
8576 free_percpu(pmu->pmu_disable_count);
8579 EXPORT_SYMBOL_GPL(perf_pmu_register);
8581 void perf_pmu_unregister(struct pmu *pmu)
8583 mutex_lock(&pmus_lock);
8584 list_del_rcu(&pmu->entry);
8585 mutex_unlock(&pmus_lock);
8588 * We dereference the pmu list under both SRCU and regular RCU, so
8589 * synchronize against both of those.
8591 synchronize_srcu(&pmus_srcu);
8594 free_percpu(pmu->pmu_disable_count);
8595 if (pmu->type >= PERF_TYPE_MAX)
8596 idr_remove(&pmu_idr, pmu->type);
8597 if (pmu->nr_addr_filters)
8598 device_remove_file(pmu->dev, &dev_attr_nr_addr_filters);
8599 device_del(pmu->dev);
8600 put_device(pmu->dev);
8601 free_pmu_context(pmu);
8603 EXPORT_SYMBOL_GPL(perf_pmu_unregister);
8605 static int perf_try_init_event(struct pmu *pmu, struct perf_event *event)
8607 struct perf_event_context *ctx = NULL;
8610 if (!try_module_get(pmu->module))
8613 if (event->group_leader != event) {
8615 * This ctx->mutex can nest when we're called through
8616 * inheritance. See the perf_event_ctx_lock_nested() comment.
8618 ctx = perf_event_ctx_lock_nested(event->group_leader,
8619 SINGLE_DEPTH_NESTING);
8624 ret = pmu->event_init(event);
8627 perf_event_ctx_unlock(event->group_leader, ctx);
8630 module_put(pmu->module);
8635 static struct pmu *perf_init_event(struct perf_event *event)
8637 struct pmu *pmu = NULL;
8641 idx = srcu_read_lock(&pmus_srcu);
8644 pmu = idr_find(&pmu_idr, event->attr.type);
8647 ret = perf_try_init_event(pmu, event);
8653 list_for_each_entry_rcu(pmu, &pmus, entry) {
8654 ret = perf_try_init_event(pmu, event);
8658 if (ret != -ENOENT) {
8663 pmu = ERR_PTR(-ENOENT);
8665 srcu_read_unlock(&pmus_srcu, idx);
8670 static void account_event_cpu(struct perf_event *event, int cpu)
8675 if (is_cgroup_event(event))
8676 atomic_inc(&per_cpu(perf_cgroup_events, cpu));
8679 /* Freq events need the tick to stay alive (see perf_event_task_tick). */
8680 static void account_freq_event_nohz(void)
8682 #ifdef CONFIG_NO_HZ_FULL
8683 /* Lock so we don't race with concurrent unaccount */
8684 spin_lock(&nr_freq_lock);
8685 if (atomic_inc_return(&nr_freq_events) == 1)
8686 tick_nohz_dep_set(TICK_DEP_BIT_PERF_EVENTS);
8687 spin_unlock(&nr_freq_lock);
8691 static void account_freq_event(void)
8693 if (tick_nohz_full_enabled())
8694 account_freq_event_nohz();
8696 atomic_inc(&nr_freq_events);
8700 static void account_event(struct perf_event *event)
8707 if (event->attach_state & PERF_ATTACH_TASK)
8709 if (event->attr.mmap || event->attr.mmap_data)
8710 atomic_inc(&nr_mmap_events);
8711 if (event->attr.comm)
8712 atomic_inc(&nr_comm_events);
8713 if (event->attr.task)
8714 atomic_inc(&nr_task_events);
8715 if (event->attr.freq)
8716 account_freq_event();
8717 if (event->attr.context_switch) {
8718 atomic_inc(&nr_switch_events);
8721 if (has_branch_stack(event))
8723 if (is_cgroup_event(event))
8727 if (atomic_inc_not_zero(&perf_sched_count))
8730 mutex_lock(&perf_sched_mutex);
8731 if (!atomic_read(&perf_sched_count)) {
8732 static_branch_enable(&perf_sched_events);
8734 * Guarantee that all CPUs observe they key change and
8735 * call the perf scheduling hooks before proceeding to
8736 * install events that need them.
8738 synchronize_sched();
8741 * Now that we have waited for the sync_sched(), allow further
8742 * increments to by-pass the mutex.
8744 atomic_inc(&perf_sched_count);
8745 mutex_unlock(&perf_sched_mutex);
8749 account_event_cpu(event, event->cpu);
8753 * Allocate and initialize a event structure
8755 static struct perf_event *
8756 perf_event_alloc(struct perf_event_attr *attr, int cpu,
8757 struct task_struct *task,
8758 struct perf_event *group_leader,
8759 struct perf_event *parent_event,
8760 perf_overflow_handler_t overflow_handler,
8761 void *context, int cgroup_fd)
8764 struct perf_event *event;
8765 struct hw_perf_event *hwc;
8768 if ((unsigned)cpu >= nr_cpu_ids) {
8769 if (!task || cpu != -1)
8770 return ERR_PTR(-EINVAL);
8773 event = kzalloc(sizeof(*event), GFP_KERNEL);
8775 return ERR_PTR(-ENOMEM);
8778 * Single events are their own group leaders, with an
8779 * empty sibling list:
8782 group_leader = event;
8784 mutex_init(&event->child_mutex);
8785 INIT_LIST_HEAD(&event->child_list);
8787 INIT_LIST_HEAD(&event->group_entry);
8788 INIT_LIST_HEAD(&event->event_entry);
8789 INIT_LIST_HEAD(&event->sibling_list);
8790 INIT_LIST_HEAD(&event->rb_entry);
8791 INIT_LIST_HEAD(&event->active_entry);
8792 INIT_LIST_HEAD(&event->addr_filters.list);
8793 INIT_HLIST_NODE(&event->hlist_entry);
8796 init_waitqueue_head(&event->waitq);
8797 init_irq_work(&event->pending, perf_pending_event);
8799 mutex_init(&event->mmap_mutex);
8800 raw_spin_lock_init(&event->addr_filters.lock);
8802 atomic_long_set(&event->refcount, 1);
8804 event->attr = *attr;
8805 event->group_leader = group_leader;
8809 event->parent = parent_event;
8811 event->ns = get_pid_ns(task_active_pid_ns(current));
8812 event->id = atomic64_inc_return(&perf_event_id);
8814 event->state = PERF_EVENT_STATE_INACTIVE;
8817 event->attach_state = PERF_ATTACH_TASK;
8819 * XXX pmu::event_init needs to know what task to account to
8820 * and we cannot use the ctx information because we need the
8821 * pmu before we get a ctx.
8823 event->hw.target = task;
8826 event->clock = &local_clock;
8828 event->clock = parent_event->clock;
8830 if (!overflow_handler && parent_event) {
8831 overflow_handler = parent_event->overflow_handler;
8832 context = parent_event->overflow_handler_context;
8835 if (overflow_handler) {
8836 event->overflow_handler = overflow_handler;
8837 event->overflow_handler_context = context;
8838 } else if (is_write_backward(event)){
8839 event->overflow_handler = perf_event_output_backward;
8840 event->overflow_handler_context = NULL;
8842 event->overflow_handler = perf_event_output_forward;
8843 event->overflow_handler_context = NULL;
8846 perf_event__state_init(event);
8851 hwc->sample_period = attr->sample_period;
8852 if (attr->freq && attr->sample_freq)
8853 hwc->sample_period = 1;
8854 hwc->last_period = hwc->sample_period;
8856 local64_set(&hwc->period_left, hwc->sample_period);
8859 * we currently do not support PERF_FORMAT_GROUP on inherited events
8861 if (attr->inherit && (attr->read_format & PERF_FORMAT_GROUP))
8864 if (!has_branch_stack(event))
8865 event->attr.branch_sample_type = 0;
8867 if (cgroup_fd != -1) {
8868 err = perf_cgroup_connect(cgroup_fd, event, attr, group_leader);
8873 pmu = perf_init_event(event);
8876 else if (IS_ERR(pmu)) {
8881 err = exclusive_event_init(event);
8885 if (has_addr_filter(event)) {
8886 event->addr_filters_offs = kcalloc(pmu->nr_addr_filters,
8887 sizeof(unsigned long),
8889 if (!event->addr_filters_offs)
8892 /* force hw sync on the address filters */
8893 event->addr_filters_gen = 1;
8896 if (!event->parent) {
8897 if (event->attr.sample_type & PERF_SAMPLE_CALLCHAIN) {
8898 err = get_callchain_buffers();
8900 goto err_addr_filters;
8904 /* symmetric to unaccount_event() in _free_event() */
8905 account_event(event);
8910 kfree(event->addr_filters_offs);
8913 exclusive_event_destroy(event);
8917 event->destroy(event);
8918 module_put(pmu->module);
8920 if (is_cgroup_event(event))
8921 perf_detach_cgroup(event);
8923 put_pid_ns(event->ns);
8926 return ERR_PTR(err);
8929 static int perf_copy_attr(struct perf_event_attr __user *uattr,
8930 struct perf_event_attr *attr)
8935 if (!access_ok(VERIFY_WRITE, uattr, PERF_ATTR_SIZE_VER0))
8939 * zero the full structure, so that a short copy will be nice.
8941 memset(attr, 0, sizeof(*attr));
8943 ret = get_user(size, &uattr->size);
8947 if (size > PAGE_SIZE) /* silly large */
8950 if (!size) /* abi compat */
8951 size = PERF_ATTR_SIZE_VER0;
8953 if (size < PERF_ATTR_SIZE_VER0)
8957 * If we're handed a bigger struct than we know of,
8958 * ensure all the unknown bits are 0 - i.e. new
8959 * user-space does not rely on any kernel feature
8960 * extensions we dont know about yet.
8962 if (size > sizeof(*attr)) {
8963 unsigned char __user *addr;
8964 unsigned char __user *end;
8967 addr = (void __user *)uattr + sizeof(*attr);
8968 end = (void __user *)uattr + size;
8970 for (; addr < end; addr++) {
8971 ret = get_user(val, addr);
8977 size = sizeof(*attr);
8980 ret = copy_from_user(attr, uattr, size);
8984 if (attr->__reserved_1)
8987 if (attr->sample_type & ~(PERF_SAMPLE_MAX-1))
8990 if (attr->read_format & ~(PERF_FORMAT_MAX-1))
8993 if (attr->sample_type & PERF_SAMPLE_BRANCH_STACK) {
8994 u64 mask = attr->branch_sample_type;
8996 /* only using defined bits */
8997 if (mask & ~(PERF_SAMPLE_BRANCH_MAX-1))
9000 /* at least one branch bit must be set */
9001 if (!(mask & ~PERF_SAMPLE_BRANCH_PLM_ALL))
9004 /* propagate priv level, when not set for branch */
9005 if (!(mask & PERF_SAMPLE_BRANCH_PLM_ALL)) {
9007 /* exclude_kernel checked on syscall entry */
9008 if (!attr->exclude_kernel)
9009 mask |= PERF_SAMPLE_BRANCH_KERNEL;
9011 if (!attr->exclude_user)
9012 mask |= PERF_SAMPLE_BRANCH_USER;
9014 if (!attr->exclude_hv)
9015 mask |= PERF_SAMPLE_BRANCH_HV;
9017 * adjust user setting (for HW filter setup)
9019 attr->branch_sample_type = mask;
9021 /* privileged levels capture (kernel, hv): check permissions */
9022 if ((mask & PERF_SAMPLE_BRANCH_PERM_PLM)
9023 && perf_paranoid_kernel() && !capable(CAP_SYS_ADMIN))
9027 if (attr->sample_type & PERF_SAMPLE_REGS_USER) {
9028 ret = perf_reg_validate(attr->sample_regs_user);
9033 if (attr->sample_type & PERF_SAMPLE_STACK_USER) {
9034 if (!arch_perf_have_user_stack_dump())
9038 * We have __u32 type for the size, but so far
9039 * we can only use __u16 as maximum due to the
9040 * __u16 sample size limit.
9042 if (attr->sample_stack_user >= USHRT_MAX)
9044 else if (!IS_ALIGNED(attr->sample_stack_user, sizeof(u64)))
9048 if (attr->sample_type & PERF_SAMPLE_REGS_INTR)
9049 ret = perf_reg_validate(attr->sample_regs_intr);
9054 put_user(sizeof(*attr), &uattr->size);
9060 perf_event_set_output(struct perf_event *event, struct perf_event *output_event)
9062 struct ring_buffer *rb = NULL;
9068 /* don't allow circular references */
9069 if (event == output_event)
9073 * Don't allow cross-cpu buffers
9075 if (output_event->cpu != event->cpu)
9079 * If its not a per-cpu rb, it must be the same task.
9081 if (output_event->cpu == -1 && output_event->ctx != event->ctx)
9085 * Mixing clocks in the same buffer is trouble you don't need.
9087 if (output_event->clock != event->clock)
9091 * Either writing ring buffer from beginning or from end.
9092 * Mixing is not allowed.
9094 if (is_write_backward(output_event) != is_write_backward(event))
9098 * If both events generate aux data, they must be on the same PMU
9100 if (has_aux(event) && has_aux(output_event) &&
9101 event->pmu != output_event->pmu)
9105 mutex_lock(&event->mmap_mutex);
9106 /* Can't redirect output if we've got an active mmap() */
9107 if (atomic_read(&event->mmap_count))
9111 /* get the rb we want to redirect to */
9112 rb = ring_buffer_get(output_event);
9117 ring_buffer_attach(event, rb);
9121 mutex_unlock(&event->mmap_mutex);
9127 static void mutex_lock_double(struct mutex *a, struct mutex *b)
9133 mutex_lock_nested(b, SINGLE_DEPTH_NESTING);
9136 static int perf_event_set_clock(struct perf_event *event, clockid_t clk_id)
9138 bool nmi_safe = false;
9141 case CLOCK_MONOTONIC:
9142 event->clock = &ktime_get_mono_fast_ns;
9146 case CLOCK_MONOTONIC_RAW:
9147 event->clock = &ktime_get_raw_fast_ns;
9151 case CLOCK_REALTIME:
9152 event->clock = &ktime_get_real_ns;
9155 case CLOCK_BOOTTIME:
9156 event->clock = &ktime_get_boot_ns;
9160 event->clock = &ktime_get_tai_ns;
9167 if (!nmi_safe && !(event->pmu->capabilities & PERF_PMU_CAP_NO_NMI))
9174 * sys_perf_event_open - open a performance event, associate it to a task/cpu
9176 * @attr_uptr: event_id type attributes for monitoring/sampling
9179 * @group_fd: group leader event fd
9181 SYSCALL_DEFINE5(perf_event_open,
9182 struct perf_event_attr __user *, attr_uptr,
9183 pid_t, pid, int, cpu, int, group_fd, unsigned long, flags)
9185 struct perf_event *group_leader = NULL, *output_event = NULL;
9186 struct perf_event *event, *sibling;
9187 struct perf_event_attr attr;
9188 struct perf_event_context *ctx, *uninitialized_var(gctx);
9189 struct file *event_file = NULL;
9190 struct fd group = {NULL, 0};
9191 struct task_struct *task = NULL;
9196 int f_flags = O_RDWR;
9199 /* for future expandability... */
9200 if (flags & ~PERF_FLAG_ALL)
9203 err = perf_copy_attr(attr_uptr, &attr);
9207 if (!attr.exclude_kernel) {
9208 if (perf_paranoid_kernel() && !capable(CAP_SYS_ADMIN))
9213 if (attr.sample_freq > sysctl_perf_event_sample_rate)
9216 if (attr.sample_period & (1ULL << 63))
9221 * In cgroup mode, the pid argument is used to pass the fd
9222 * opened to the cgroup directory in cgroupfs. The cpu argument
9223 * designates the cpu on which to monitor threads from that
9226 if ((flags & PERF_FLAG_PID_CGROUP) && (pid == -1 || cpu == -1))
9229 if (flags & PERF_FLAG_FD_CLOEXEC)
9230 f_flags |= O_CLOEXEC;
9232 event_fd = get_unused_fd_flags(f_flags);
9236 if (group_fd != -1) {
9237 err = perf_fget_light(group_fd, &group);
9240 group_leader = group.file->private_data;
9241 if (flags & PERF_FLAG_FD_OUTPUT)
9242 output_event = group_leader;
9243 if (flags & PERF_FLAG_FD_NO_GROUP)
9244 group_leader = NULL;
9247 if (pid != -1 && !(flags & PERF_FLAG_PID_CGROUP)) {
9248 task = find_lively_task_by_vpid(pid);
9250 err = PTR_ERR(task);
9255 if (task && group_leader &&
9256 group_leader->attr.inherit != attr.inherit) {
9264 err = mutex_lock_interruptible(&task->signal->cred_guard_mutex);
9269 * Reuse ptrace permission checks for now.
9271 * We must hold cred_guard_mutex across this and any potential
9272 * perf_install_in_context() call for this new event to
9273 * serialize against exec() altering our credentials (and the
9274 * perf_event_exit_task() that could imply).
9277 if (!ptrace_may_access(task, PTRACE_MODE_READ_REALCREDS))
9281 if (flags & PERF_FLAG_PID_CGROUP)
9284 event = perf_event_alloc(&attr, cpu, task, group_leader, NULL,
9285 NULL, NULL, cgroup_fd);
9286 if (IS_ERR(event)) {
9287 err = PTR_ERR(event);
9291 if (is_sampling_event(event)) {
9292 if (event->pmu->capabilities & PERF_PMU_CAP_NO_INTERRUPT) {
9299 * Special case software events and allow them to be part of
9300 * any hardware group.
9304 if (attr.use_clockid) {
9305 err = perf_event_set_clock(event, attr.clockid);
9311 (is_software_event(event) != is_software_event(group_leader))) {
9312 if (is_software_event(event)) {
9314 * If event and group_leader are not both a software
9315 * event, and event is, then group leader is not.
9317 * Allow the addition of software events to !software
9318 * groups, this is safe because software events never
9321 pmu = group_leader->pmu;
9322 } else if (is_software_event(group_leader) &&
9323 (group_leader->group_flags & PERF_GROUP_SOFTWARE)) {
9325 * In case the group is a pure software group, and we
9326 * try to add a hardware event, move the whole group to
9327 * the hardware context.
9334 * Get the target context (task or percpu):
9336 ctx = find_get_context(pmu, task, event);
9342 if ((pmu->capabilities & PERF_PMU_CAP_EXCLUSIVE) && group_leader) {
9348 * Look up the group leader (we will attach this event to it):
9354 * Do not allow a recursive hierarchy (this new sibling
9355 * becoming part of another group-sibling):
9357 if (group_leader->group_leader != group_leader)
9360 /* All events in a group should have the same clock */
9361 if (group_leader->clock != event->clock)
9365 * Do not allow to attach to a group in a different
9366 * task or CPU context:
9370 * Make sure we're both on the same task, or both
9373 if (group_leader->ctx->task != ctx->task)
9377 * Make sure we're both events for the same CPU;
9378 * grouping events for different CPUs is broken; since
9379 * you can never concurrently schedule them anyhow.
9381 if (group_leader->cpu != event->cpu)
9384 if (group_leader->ctx != ctx)
9389 * Only a group leader can be exclusive or pinned
9391 if (attr.exclusive || attr.pinned)
9396 err = perf_event_set_output(event, output_event);
9401 event_file = anon_inode_getfile("[perf_event]", &perf_fops, event,
9403 if (IS_ERR(event_file)) {
9404 err = PTR_ERR(event_file);
9410 gctx = group_leader->ctx;
9411 mutex_lock_double(&gctx->mutex, &ctx->mutex);
9412 if (gctx->task == TASK_TOMBSTONE) {
9417 mutex_lock(&ctx->mutex);
9420 if (ctx->task == TASK_TOMBSTONE) {
9425 if (!perf_event_validate_size(event)) {
9431 * Must be under the same ctx::mutex as perf_install_in_context(),
9432 * because we need to serialize with concurrent event creation.
9434 if (!exclusive_event_installable(event, ctx)) {
9435 /* exclusive and group stuff are assumed mutually exclusive */
9436 WARN_ON_ONCE(move_group);
9442 WARN_ON_ONCE(ctx->parent_ctx);
9445 * This is the point on no return; we cannot fail hereafter. This is
9446 * where we start modifying current state.
9451 * See perf_event_ctx_lock() for comments on the details
9452 * of swizzling perf_event::ctx.
9454 perf_remove_from_context(group_leader, 0);
9456 list_for_each_entry(sibling, &group_leader->sibling_list,
9458 perf_remove_from_context(sibling, 0);
9463 * Wait for everybody to stop referencing the events through
9464 * the old lists, before installing it on new lists.
9469 * Install the group siblings before the group leader.
9471 * Because a group leader will try and install the entire group
9472 * (through the sibling list, which is still in-tact), we can
9473 * end up with siblings installed in the wrong context.
9475 * By installing siblings first we NO-OP because they're not
9476 * reachable through the group lists.
9478 list_for_each_entry(sibling, &group_leader->sibling_list,
9480 perf_event__state_init(sibling);
9481 perf_install_in_context(ctx, sibling, sibling->cpu);
9486 * Removing from the context ends up with disabled
9487 * event. What we want here is event in the initial
9488 * startup state, ready to be add into new context.
9490 perf_event__state_init(group_leader);
9491 perf_install_in_context(ctx, group_leader, group_leader->cpu);
9495 * Now that all events are installed in @ctx, nothing
9496 * references @gctx anymore, so drop the last reference we have
9503 * Precalculate sample_data sizes; do while holding ctx::mutex such
9504 * that we're serialized against further additions and before
9505 * perf_install_in_context() which is the point the event is active and
9506 * can use these values.
9508 perf_event__header_size(event);
9509 perf_event__id_header_size(event);
9511 event->owner = current;
9513 perf_install_in_context(ctx, event, event->cpu);
9514 perf_unpin_context(ctx);
9517 mutex_unlock(&gctx->mutex);
9518 mutex_unlock(&ctx->mutex);
9521 mutex_unlock(&task->signal->cred_guard_mutex);
9522 put_task_struct(task);
9527 mutex_lock(¤t->perf_event_mutex);
9528 list_add_tail(&event->owner_entry, ¤t->perf_event_list);
9529 mutex_unlock(¤t->perf_event_mutex);
9532 * Drop the reference on the group_event after placing the
9533 * new event on the sibling_list. This ensures destruction
9534 * of the group leader will find the pointer to itself in
9535 * perf_group_detach().
9538 fd_install(event_fd, event_file);
9543 mutex_unlock(&gctx->mutex);
9544 mutex_unlock(&ctx->mutex);
9548 perf_unpin_context(ctx);
9552 * If event_file is set, the fput() above will have called ->release()
9553 * and that will take care of freeing the event.
9559 mutex_unlock(&task->signal->cred_guard_mutex);
9564 put_task_struct(task);
9568 put_unused_fd(event_fd);
9573 * perf_event_create_kernel_counter
9575 * @attr: attributes of the counter to create
9576 * @cpu: cpu in which the counter is bound
9577 * @task: task to profile (NULL for percpu)
9580 perf_event_create_kernel_counter(struct perf_event_attr *attr, int cpu,
9581 struct task_struct *task,
9582 perf_overflow_handler_t overflow_handler,
9585 struct perf_event_context *ctx;
9586 struct perf_event *event;
9590 * Get the target context (task or percpu):
9593 event = perf_event_alloc(attr, cpu, task, NULL, NULL,
9594 overflow_handler, context, -1);
9595 if (IS_ERR(event)) {
9596 err = PTR_ERR(event);
9600 /* Mark owner so we could distinguish it from user events. */
9601 event->owner = TASK_TOMBSTONE;
9603 ctx = find_get_context(event->pmu, task, event);
9609 WARN_ON_ONCE(ctx->parent_ctx);
9610 mutex_lock(&ctx->mutex);
9611 if (ctx->task == TASK_TOMBSTONE) {
9616 if (!exclusive_event_installable(event, ctx)) {
9621 perf_install_in_context(ctx, event, cpu);
9622 perf_unpin_context(ctx);
9623 mutex_unlock(&ctx->mutex);
9628 mutex_unlock(&ctx->mutex);
9629 perf_unpin_context(ctx);
9634 return ERR_PTR(err);
9636 EXPORT_SYMBOL_GPL(perf_event_create_kernel_counter);
9638 void perf_pmu_migrate_context(struct pmu *pmu, int src_cpu, int dst_cpu)
9640 struct perf_event_context *src_ctx;
9641 struct perf_event_context *dst_ctx;
9642 struct perf_event *event, *tmp;
9645 src_ctx = &per_cpu_ptr(pmu->pmu_cpu_context, src_cpu)->ctx;
9646 dst_ctx = &per_cpu_ptr(pmu->pmu_cpu_context, dst_cpu)->ctx;
9649 * See perf_event_ctx_lock() for comments on the details
9650 * of swizzling perf_event::ctx.
9652 mutex_lock_double(&src_ctx->mutex, &dst_ctx->mutex);
9653 list_for_each_entry_safe(event, tmp, &src_ctx->event_list,
9655 perf_remove_from_context(event, 0);
9656 unaccount_event_cpu(event, src_cpu);
9658 list_add(&event->migrate_entry, &events);
9662 * Wait for the events to quiesce before re-instating them.
9667 * Re-instate events in 2 passes.
9669 * Skip over group leaders and only install siblings on this first
9670 * pass, siblings will not get enabled without a leader, however a
9671 * leader will enable its siblings, even if those are still on the old
9674 list_for_each_entry_safe(event, tmp, &events, migrate_entry) {
9675 if (event->group_leader == event)
9678 list_del(&event->migrate_entry);
9679 if (event->state >= PERF_EVENT_STATE_OFF)
9680 event->state = PERF_EVENT_STATE_INACTIVE;
9681 account_event_cpu(event, dst_cpu);
9682 perf_install_in_context(dst_ctx, event, dst_cpu);
9687 * Once all the siblings are setup properly, install the group leaders
9690 list_for_each_entry_safe(event, tmp, &events, migrate_entry) {
9691 list_del(&event->migrate_entry);
9692 if (event->state >= PERF_EVENT_STATE_OFF)
9693 event->state = PERF_EVENT_STATE_INACTIVE;
9694 account_event_cpu(event, dst_cpu);
9695 perf_install_in_context(dst_ctx, event, dst_cpu);
9698 mutex_unlock(&dst_ctx->mutex);
9699 mutex_unlock(&src_ctx->mutex);
9701 EXPORT_SYMBOL_GPL(perf_pmu_migrate_context);
9703 static void sync_child_event(struct perf_event *child_event,
9704 struct task_struct *child)
9706 struct perf_event *parent_event = child_event->parent;
9709 if (child_event->attr.inherit_stat)
9710 perf_event_read_event(child_event, child);
9712 child_val = perf_event_count(child_event);
9715 * Add back the child's count to the parent's count:
9717 atomic64_add(child_val, &parent_event->child_count);
9718 atomic64_add(child_event->total_time_enabled,
9719 &parent_event->child_total_time_enabled);
9720 atomic64_add(child_event->total_time_running,
9721 &parent_event->child_total_time_running);
9725 perf_event_exit_event(struct perf_event *child_event,
9726 struct perf_event_context *child_ctx,
9727 struct task_struct *child)
9729 struct perf_event *parent_event = child_event->parent;
9732 * Do not destroy the 'original' grouping; because of the context
9733 * switch optimization the original events could've ended up in a
9734 * random child task.
9736 * If we were to destroy the original group, all group related
9737 * operations would cease to function properly after this random
9740 * Do destroy all inherited groups, we don't care about those
9741 * and being thorough is better.
9743 raw_spin_lock_irq(&child_ctx->lock);
9744 WARN_ON_ONCE(child_ctx->is_active);
9747 perf_group_detach(child_event);
9748 list_del_event(child_event, child_ctx);
9749 child_event->state = PERF_EVENT_STATE_EXIT; /* is_event_hup() */
9750 raw_spin_unlock_irq(&child_ctx->lock);
9753 * Parent events are governed by their filedesc, retain them.
9755 if (!parent_event) {
9756 perf_event_wakeup(child_event);
9760 * Child events can be cleaned up.
9763 sync_child_event(child_event, child);
9766 * Remove this event from the parent's list
9768 WARN_ON_ONCE(parent_event->ctx->parent_ctx);
9769 mutex_lock(&parent_event->child_mutex);
9770 list_del_init(&child_event->child_list);
9771 mutex_unlock(&parent_event->child_mutex);
9774 * Kick perf_poll() for is_event_hup().
9776 perf_event_wakeup(parent_event);
9777 free_event(child_event);
9778 put_event(parent_event);
9781 static void perf_event_exit_task_context(struct task_struct *child, int ctxn)
9783 struct perf_event_context *child_ctx, *clone_ctx = NULL;
9784 struct perf_event *child_event, *next;
9786 WARN_ON_ONCE(child != current);
9788 child_ctx = perf_pin_task_context(child, ctxn);
9793 * In order to reduce the amount of tricky in ctx tear-down, we hold
9794 * ctx::mutex over the entire thing. This serializes against almost
9795 * everything that wants to access the ctx.
9797 * The exception is sys_perf_event_open() /
9798 * perf_event_create_kernel_count() which does find_get_context()
9799 * without ctx::mutex (it cannot because of the move_group double mutex
9800 * lock thing). See the comments in perf_install_in_context().
9802 mutex_lock(&child_ctx->mutex);
9805 * In a single ctx::lock section, de-schedule the events and detach the
9806 * context from the task such that we cannot ever get it scheduled back
9809 raw_spin_lock_irq(&child_ctx->lock);
9810 task_ctx_sched_out(__get_cpu_context(child_ctx), child_ctx);
9813 * Now that the context is inactive, destroy the task <-> ctx relation
9814 * and mark the context dead.
9816 RCU_INIT_POINTER(child->perf_event_ctxp[ctxn], NULL);
9817 put_ctx(child_ctx); /* cannot be last */
9818 WRITE_ONCE(child_ctx->task, TASK_TOMBSTONE);
9819 put_task_struct(current); /* cannot be last */
9821 clone_ctx = unclone_ctx(child_ctx);
9822 raw_spin_unlock_irq(&child_ctx->lock);
9828 * Report the task dead after unscheduling the events so that we
9829 * won't get any samples after PERF_RECORD_EXIT. We can however still
9830 * get a few PERF_RECORD_READ events.
9832 perf_event_task(child, child_ctx, 0);
9834 list_for_each_entry_safe(child_event, next, &child_ctx->event_list, event_entry)
9835 perf_event_exit_event(child_event, child_ctx, child);
9837 mutex_unlock(&child_ctx->mutex);
9843 * When a child task exits, feed back event values to parent events.
9845 * Can be called with cred_guard_mutex held when called from
9846 * install_exec_creds().
9848 void perf_event_exit_task(struct task_struct *child)
9850 struct perf_event *event, *tmp;
9853 mutex_lock(&child->perf_event_mutex);
9854 list_for_each_entry_safe(event, tmp, &child->perf_event_list,
9856 list_del_init(&event->owner_entry);
9859 * Ensure the list deletion is visible before we clear
9860 * the owner, closes a race against perf_release() where
9861 * we need to serialize on the owner->perf_event_mutex.
9863 smp_store_release(&event->owner, NULL);
9865 mutex_unlock(&child->perf_event_mutex);
9867 for_each_task_context_nr(ctxn)
9868 perf_event_exit_task_context(child, ctxn);
9871 * The perf_event_exit_task_context calls perf_event_task
9872 * with child's task_ctx, which generates EXIT events for
9873 * child contexts and sets child->perf_event_ctxp[] to NULL.
9874 * At this point we need to send EXIT events to cpu contexts.
9876 perf_event_task(child, NULL, 0);
9879 static void perf_free_event(struct perf_event *event,
9880 struct perf_event_context *ctx)
9882 struct perf_event *parent = event->parent;
9884 if (WARN_ON_ONCE(!parent))
9887 mutex_lock(&parent->child_mutex);
9888 list_del_init(&event->child_list);
9889 mutex_unlock(&parent->child_mutex);
9893 raw_spin_lock_irq(&ctx->lock);
9894 perf_group_detach(event);
9895 list_del_event(event, ctx);
9896 raw_spin_unlock_irq(&ctx->lock);
9901 * Free an unexposed, unused context as created by inheritance by
9902 * perf_event_init_task below, used by fork() in case of fail.
9904 * Not all locks are strictly required, but take them anyway to be nice and
9905 * help out with the lockdep assertions.
9907 void perf_event_free_task(struct task_struct *task)
9909 struct perf_event_context *ctx;
9910 struct perf_event *event, *tmp;
9913 for_each_task_context_nr(ctxn) {
9914 ctx = task->perf_event_ctxp[ctxn];
9918 mutex_lock(&ctx->mutex);
9920 list_for_each_entry_safe(event, tmp, &ctx->pinned_groups,
9922 perf_free_event(event, ctx);
9924 list_for_each_entry_safe(event, tmp, &ctx->flexible_groups,
9926 perf_free_event(event, ctx);
9928 if (!list_empty(&ctx->pinned_groups) ||
9929 !list_empty(&ctx->flexible_groups))
9932 mutex_unlock(&ctx->mutex);
9938 void perf_event_delayed_put(struct task_struct *task)
9942 for_each_task_context_nr(ctxn)
9943 WARN_ON_ONCE(task->perf_event_ctxp[ctxn]);
9946 struct file *perf_event_get(unsigned int fd)
9950 file = fget_raw(fd);
9952 return ERR_PTR(-EBADF);
9954 if (file->f_op != &perf_fops) {
9956 return ERR_PTR(-EBADF);
9962 const struct perf_event_attr *perf_event_attrs(struct perf_event *event)
9965 return ERR_PTR(-EINVAL);
9967 return &event->attr;
9971 * inherit a event from parent task to child task:
9973 static struct perf_event *
9974 inherit_event(struct perf_event *parent_event,
9975 struct task_struct *parent,
9976 struct perf_event_context *parent_ctx,
9977 struct task_struct *child,
9978 struct perf_event *group_leader,
9979 struct perf_event_context *child_ctx)
9981 enum perf_event_active_state parent_state = parent_event->state;
9982 struct perf_event *child_event;
9983 unsigned long flags;
9986 * Instead of creating recursive hierarchies of events,
9987 * we link inherited events back to the original parent,
9988 * which has a filp for sure, which we use as the reference
9991 if (parent_event->parent)
9992 parent_event = parent_event->parent;
9994 child_event = perf_event_alloc(&parent_event->attr,
9997 group_leader, parent_event,
9999 if (IS_ERR(child_event))
10000 return child_event;
10003 * is_orphaned_event() and list_add_tail(&parent_event->child_list)
10004 * must be under the same lock in order to serialize against
10005 * perf_event_release_kernel(), such that either we must observe
10006 * is_orphaned_event() or they will observe us on the child_list.
10008 mutex_lock(&parent_event->child_mutex);
10009 if (is_orphaned_event(parent_event) ||
10010 !atomic_long_inc_not_zero(&parent_event->refcount)) {
10011 mutex_unlock(&parent_event->child_mutex);
10012 free_event(child_event);
10016 get_ctx(child_ctx);
10019 * Make the child state follow the state of the parent event,
10020 * not its attr.disabled bit. We hold the parent's mutex,
10021 * so we won't race with perf_event_{en, dis}able_family.
10023 if (parent_state >= PERF_EVENT_STATE_INACTIVE)
10024 child_event->state = PERF_EVENT_STATE_INACTIVE;
10026 child_event->state = PERF_EVENT_STATE_OFF;
10028 if (parent_event->attr.freq) {
10029 u64 sample_period = parent_event->hw.sample_period;
10030 struct hw_perf_event *hwc = &child_event->hw;
10032 hwc->sample_period = sample_period;
10033 hwc->last_period = sample_period;
10035 local64_set(&hwc->period_left, sample_period);
10038 child_event->ctx = child_ctx;
10039 child_event->overflow_handler = parent_event->overflow_handler;
10040 child_event->overflow_handler_context
10041 = parent_event->overflow_handler_context;
10044 * Precalculate sample_data sizes
10046 perf_event__header_size(child_event);
10047 perf_event__id_header_size(child_event);
10050 * Link it up in the child's context:
10052 raw_spin_lock_irqsave(&child_ctx->lock, flags);
10053 add_event_to_ctx(child_event, child_ctx);
10054 raw_spin_unlock_irqrestore(&child_ctx->lock, flags);
10057 * Link this into the parent event's child list
10059 list_add_tail(&child_event->child_list, &parent_event->child_list);
10060 mutex_unlock(&parent_event->child_mutex);
10062 return child_event;
10065 static int inherit_group(struct perf_event *parent_event,
10066 struct task_struct *parent,
10067 struct perf_event_context *parent_ctx,
10068 struct task_struct *child,
10069 struct perf_event_context *child_ctx)
10071 struct perf_event *leader;
10072 struct perf_event *sub;
10073 struct perf_event *child_ctr;
10075 leader = inherit_event(parent_event, parent, parent_ctx,
10076 child, NULL, child_ctx);
10077 if (IS_ERR(leader))
10078 return PTR_ERR(leader);
10079 list_for_each_entry(sub, &parent_event->sibling_list, group_entry) {
10080 child_ctr = inherit_event(sub, parent, parent_ctx,
10081 child, leader, child_ctx);
10082 if (IS_ERR(child_ctr))
10083 return PTR_ERR(child_ctr);
10089 inherit_task_group(struct perf_event *event, struct task_struct *parent,
10090 struct perf_event_context *parent_ctx,
10091 struct task_struct *child, int ctxn,
10092 int *inherited_all)
10095 struct perf_event_context *child_ctx;
10097 if (!event->attr.inherit) {
10098 *inherited_all = 0;
10102 child_ctx = child->perf_event_ctxp[ctxn];
10105 * This is executed from the parent task context, so
10106 * inherit events that have been marked for cloning.
10107 * First allocate and initialize a context for the
10111 child_ctx = alloc_perf_context(parent_ctx->pmu, child);
10115 child->perf_event_ctxp[ctxn] = child_ctx;
10118 ret = inherit_group(event, parent, parent_ctx,
10122 *inherited_all = 0;
10128 * Initialize the perf_event context in task_struct
10130 static int perf_event_init_context(struct task_struct *child, int ctxn)
10132 struct perf_event_context *child_ctx, *parent_ctx;
10133 struct perf_event_context *cloned_ctx;
10134 struct perf_event *event;
10135 struct task_struct *parent = current;
10136 int inherited_all = 1;
10137 unsigned long flags;
10140 if (likely(!parent->perf_event_ctxp[ctxn]))
10144 * If the parent's context is a clone, pin it so it won't get
10145 * swapped under us.
10147 parent_ctx = perf_pin_task_context(parent, ctxn);
10152 * No need to check if parent_ctx != NULL here; since we saw
10153 * it non-NULL earlier, the only reason for it to become NULL
10154 * is if we exit, and since we're currently in the middle of
10155 * a fork we can't be exiting at the same time.
10159 * Lock the parent list. No need to lock the child - not PID
10160 * hashed yet and not running, so nobody can access it.
10162 mutex_lock(&parent_ctx->mutex);
10165 * We dont have to disable NMIs - we are only looking at
10166 * the list, not manipulating it:
10168 list_for_each_entry(event, &parent_ctx->pinned_groups, group_entry) {
10169 ret = inherit_task_group(event, parent, parent_ctx,
10170 child, ctxn, &inherited_all);
10176 * We can't hold ctx->lock when iterating the ->flexible_group list due
10177 * to allocations, but we need to prevent rotation because
10178 * rotate_ctx() will change the list from interrupt context.
10180 raw_spin_lock_irqsave(&parent_ctx->lock, flags);
10181 parent_ctx->rotate_disable = 1;
10182 raw_spin_unlock_irqrestore(&parent_ctx->lock, flags);
10184 list_for_each_entry(event, &parent_ctx->flexible_groups, group_entry) {
10185 ret = inherit_task_group(event, parent, parent_ctx,
10186 child, ctxn, &inherited_all);
10191 raw_spin_lock_irqsave(&parent_ctx->lock, flags);
10192 parent_ctx->rotate_disable = 0;
10194 child_ctx = child->perf_event_ctxp[ctxn];
10196 if (child_ctx && inherited_all) {
10198 * Mark the child context as a clone of the parent
10199 * context, or of whatever the parent is a clone of.
10201 * Note that if the parent is a clone, the holding of
10202 * parent_ctx->lock avoids it from being uncloned.
10204 cloned_ctx = parent_ctx->parent_ctx;
10206 child_ctx->parent_ctx = cloned_ctx;
10207 child_ctx->parent_gen = parent_ctx->parent_gen;
10209 child_ctx->parent_ctx = parent_ctx;
10210 child_ctx->parent_gen = parent_ctx->generation;
10212 get_ctx(child_ctx->parent_ctx);
10215 raw_spin_unlock_irqrestore(&parent_ctx->lock, flags);
10216 mutex_unlock(&parent_ctx->mutex);
10218 perf_unpin_context(parent_ctx);
10219 put_ctx(parent_ctx);
10225 * Initialize the perf_event context in task_struct
10227 int perf_event_init_task(struct task_struct *child)
10231 memset(child->perf_event_ctxp, 0, sizeof(child->perf_event_ctxp));
10232 mutex_init(&child->perf_event_mutex);
10233 INIT_LIST_HEAD(&child->perf_event_list);
10235 for_each_task_context_nr(ctxn) {
10236 ret = perf_event_init_context(child, ctxn);
10238 perf_event_free_task(child);
10246 static void __init perf_event_init_all_cpus(void)
10248 struct swevent_htable *swhash;
10251 for_each_possible_cpu(cpu) {
10252 swhash = &per_cpu(swevent_htable, cpu);
10253 mutex_init(&swhash->hlist_mutex);
10254 INIT_LIST_HEAD(&per_cpu(active_ctx_list, cpu));
10258 static void perf_event_init_cpu(int cpu)
10260 struct swevent_htable *swhash = &per_cpu(swevent_htable, cpu);
10262 mutex_lock(&swhash->hlist_mutex);
10263 if (swhash->hlist_refcount > 0 && !swevent_hlist_deref(swhash)) {
10264 struct swevent_hlist *hlist;
10266 hlist = kzalloc_node(sizeof(*hlist), GFP_KERNEL, cpu_to_node(cpu));
10268 rcu_assign_pointer(swhash->swevent_hlist, hlist);
10270 mutex_unlock(&swhash->hlist_mutex);
10273 #if defined CONFIG_HOTPLUG_CPU || defined CONFIG_KEXEC_CORE
10274 static void __perf_event_exit_context(void *__info)
10276 struct perf_event_context *ctx = __info;
10277 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
10278 struct perf_event *event;
10280 raw_spin_lock(&ctx->lock);
10281 list_for_each_entry(event, &ctx->event_list, event_entry)
10282 __perf_remove_from_context(event, cpuctx, ctx, (void *)DETACH_GROUP);
10283 raw_spin_unlock(&ctx->lock);
10286 static void perf_event_exit_cpu_context(int cpu)
10288 struct perf_event_context *ctx;
10292 idx = srcu_read_lock(&pmus_srcu);
10293 list_for_each_entry_rcu(pmu, &pmus, entry) {
10294 ctx = &per_cpu_ptr(pmu->pmu_cpu_context, cpu)->ctx;
10296 mutex_lock(&ctx->mutex);
10297 smp_call_function_single(cpu, __perf_event_exit_context, ctx, 1);
10298 mutex_unlock(&ctx->mutex);
10300 srcu_read_unlock(&pmus_srcu, idx);
10303 static void perf_event_exit_cpu(int cpu)
10305 perf_event_exit_cpu_context(cpu);
10308 static inline void perf_event_exit_cpu(int cpu) { }
10312 perf_reboot(struct notifier_block *notifier, unsigned long val, void *v)
10316 for_each_online_cpu(cpu)
10317 perf_event_exit_cpu(cpu);
10323 * Run the perf reboot notifier at the very last possible moment so that
10324 * the generic watchdog code runs as long as possible.
10326 static struct notifier_block perf_reboot_notifier = {
10327 .notifier_call = perf_reboot,
10328 .priority = INT_MIN,
10332 perf_cpu_notify(struct notifier_block *self, unsigned long action, void *hcpu)
10334 unsigned int cpu = (long)hcpu;
10336 switch (action & ~CPU_TASKS_FROZEN) {
10338 case CPU_UP_PREPARE:
10340 * This must be done before the CPU comes alive, because the
10341 * moment we can run tasks we can encounter (software) events.
10343 * Specifically, someone can have inherited events on kthreadd
10344 * or a pre-existing worker thread that gets re-bound.
10346 perf_event_init_cpu(cpu);
10349 case CPU_DOWN_PREPARE:
10351 * This must be done before the CPU dies because after that an
10352 * active event might want to IPI the CPU and that'll not work
10353 * so great for dead CPUs.
10355 * XXX smp_call_function_single() return -ENXIO without a warn
10356 * so we could possibly deal with this.
10358 * This is safe against new events arriving because
10359 * sys_perf_event_open() serializes against hotplug using
10360 * get_online_cpus().
10362 perf_event_exit_cpu(cpu);
10371 void __init perf_event_init(void)
10375 idr_init(&pmu_idr);
10377 perf_event_init_all_cpus();
10378 init_srcu_struct(&pmus_srcu);
10379 perf_pmu_register(&perf_swevent, "software", PERF_TYPE_SOFTWARE);
10380 perf_pmu_register(&perf_cpu_clock, NULL, -1);
10381 perf_pmu_register(&perf_task_clock, NULL, -1);
10382 perf_tp_register();
10383 perf_cpu_notifier(perf_cpu_notify);
10384 register_reboot_notifier(&perf_reboot_notifier);
10386 ret = init_hw_breakpoint();
10387 WARN(ret, "hw_breakpoint initialization failed with: %d", ret);
10390 * Build time assertion that we keep the data_head at the intended
10391 * location. IOW, validation we got the __reserved[] size right.
10393 BUILD_BUG_ON((offsetof(struct perf_event_mmap_page, data_head))
10397 ssize_t perf_event_sysfs_show(struct device *dev, struct device_attribute *attr,
10400 struct perf_pmu_events_attr *pmu_attr =
10401 container_of(attr, struct perf_pmu_events_attr, attr);
10403 if (pmu_attr->event_str)
10404 return sprintf(page, "%s\n", pmu_attr->event_str);
10408 EXPORT_SYMBOL_GPL(perf_event_sysfs_show);
10410 static int __init perf_event_sysfs_init(void)
10415 mutex_lock(&pmus_lock);
10417 ret = bus_register(&pmu_bus);
10421 list_for_each_entry(pmu, &pmus, entry) {
10422 if (!pmu->name || pmu->type < 0)
10425 ret = pmu_dev_alloc(pmu);
10426 WARN(ret, "Failed to register pmu: %s, reason %d\n", pmu->name, ret);
10428 pmu_bus_running = 1;
10432 mutex_unlock(&pmus_lock);
10436 device_initcall(perf_event_sysfs_init);
10438 #ifdef CONFIG_CGROUP_PERF
10439 static struct cgroup_subsys_state *
10440 perf_cgroup_css_alloc(struct cgroup_subsys_state *parent_css)
10442 struct perf_cgroup *jc;
10444 jc = kzalloc(sizeof(*jc), GFP_KERNEL);
10446 return ERR_PTR(-ENOMEM);
10448 jc->info = alloc_percpu(struct perf_cgroup_info);
10451 return ERR_PTR(-ENOMEM);
10457 static void perf_cgroup_css_free(struct cgroup_subsys_state *css)
10459 struct perf_cgroup *jc = container_of(css, struct perf_cgroup, css);
10461 free_percpu(jc->info);
10465 static int __perf_cgroup_move(void *info)
10467 struct task_struct *task = info;
10469 perf_cgroup_switch(task, PERF_CGROUP_SWOUT | PERF_CGROUP_SWIN);
10474 static void perf_cgroup_attach(struct cgroup_taskset *tset)
10476 struct task_struct *task;
10477 struct cgroup_subsys_state *css;
10479 cgroup_taskset_for_each(task, css, tset)
10480 task_function_call(task, __perf_cgroup_move, task);
10483 struct cgroup_subsys perf_event_cgrp_subsys = {
10484 .css_alloc = perf_cgroup_css_alloc,
10485 .css_free = perf_cgroup_css_free,
10486 .attach = perf_cgroup_attach,
10488 #endif /* CONFIG_CGROUP_PERF */