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>
49 #include <linux/sched/clock.h>
50 #include <linux/sched/mm.h>
51 #include <linux/proc_ns.h>
52 #include <linux/mount.h>
56 #include <asm/irq_regs.h>
58 typedef int (*remote_function_f)(void *);
60 struct remote_function_call {
61 struct task_struct *p;
62 remote_function_f func;
67 static void remote_function(void *data)
69 struct remote_function_call *tfc = data;
70 struct task_struct *p = tfc->p;
74 if (task_cpu(p) != smp_processor_id())
78 * Now that we're on right CPU with IRQs disabled, we can test
79 * if we hit the right task without races.
82 tfc->ret = -ESRCH; /* No such (running) process */
87 tfc->ret = tfc->func(tfc->info);
91 * task_function_call - call a function on the cpu on which a task runs
92 * @p: the task to evaluate
93 * @func: the function to be called
94 * @info: the function call argument
96 * Calls the function @func when the task is currently running. This might
97 * be on the current CPU, which just calls the function directly
99 * returns: @func return value, or
100 * -ESRCH - when the process isn't running
101 * -EAGAIN - when the process moved away
104 task_function_call(struct task_struct *p, remote_function_f func, void *info)
106 struct remote_function_call data = {
115 ret = smp_call_function_single(task_cpu(p), remote_function, &data, 1);
118 } while (ret == -EAGAIN);
124 * cpu_function_call - call a function on the cpu
125 * @func: the function to be called
126 * @info: the function call argument
128 * Calls the function @func on the remote cpu.
130 * returns: @func return value or -ENXIO when the cpu is offline
132 static int cpu_function_call(int cpu, remote_function_f func, void *info)
134 struct remote_function_call data = {
138 .ret = -ENXIO, /* No such CPU */
141 smp_call_function_single(cpu, remote_function, &data, 1);
146 static inline struct perf_cpu_context *
147 __get_cpu_context(struct perf_event_context *ctx)
149 return this_cpu_ptr(ctx->pmu->pmu_cpu_context);
152 static void perf_ctx_lock(struct perf_cpu_context *cpuctx,
153 struct perf_event_context *ctx)
155 raw_spin_lock(&cpuctx->ctx.lock);
157 raw_spin_lock(&ctx->lock);
160 static void perf_ctx_unlock(struct perf_cpu_context *cpuctx,
161 struct perf_event_context *ctx)
164 raw_spin_unlock(&ctx->lock);
165 raw_spin_unlock(&cpuctx->ctx.lock);
168 #define TASK_TOMBSTONE ((void *)-1L)
170 static bool is_kernel_event(struct perf_event *event)
172 return READ_ONCE(event->owner) == TASK_TOMBSTONE;
176 * On task ctx scheduling...
178 * When !ctx->nr_events a task context will not be scheduled. This means
179 * we can disable the scheduler hooks (for performance) without leaving
180 * pending task ctx state.
182 * This however results in two special cases:
184 * - removing the last event from a task ctx; this is relatively straight
185 * forward and is done in __perf_remove_from_context.
187 * - adding the first event to a task ctx; this is tricky because we cannot
188 * rely on ctx->is_active and therefore cannot use event_function_call().
189 * See perf_install_in_context().
191 * If ctx->nr_events, then ctx->is_active and cpuctx->task_ctx are set.
194 typedef void (*event_f)(struct perf_event *, struct perf_cpu_context *,
195 struct perf_event_context *, void *);
197 struct event_function_struct {
198 struct perf_event *event;
203 static int event_function(void *info)
205 struct event_function_struct *efs = info;
206 struct perf_event *event = efs->event;
207 struct perf_event_context *ctx = event->ctx;
208 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
209 struct perf_event_context *task_ctx = cpuctx->task_ctx;
212 WARN_ON_ONCE(!irqs_disabled());
214 perf_ctx_lock(cpuctx, task_ctx);
216 * Since we do the IPI call without holding ctx->lock things can have
217 * changed, double check we hit the task we set out to hit.
220 if (ctx->task != current) {
226 * We only use event_function_call() on established contexts,
227 * and event_function() is only ever called when active (or
228 * rather, we'll have bailed in task_function_call() or the
229 * above ctx->task != current test), therefore we must have
230 * ctx->is_active here.
232 WARN_ON_ONCE(!ctx->is_active);
234 * And since we have ctx->is_active, cpuctx->task_ctx must
237 WARN_ON_ONCE(task_ctx != ctx);
239 WARN_ON_ONCE(&cpuctx->ctx != ctx);
242 efs->func(event, cpuctx, ctx, efs->data);
244 perf_ctx_unlock(cpuctx, task_ctx);
249 static void event_function_call(struct perf_event *event, event_f func, void *data)
251 struct perf_event_context *ctx = event->ctx;
252 struct task_struct *task = READ_ONCE(ctx->task); /* verified in event_function */
253 struct event_function_struct efs = {
259 if (!event->parent) {
261 * If this is a !child event, we must hold ctx::mutex to
262 * stabilize the the event->ctx relation. See
263 * perf_event_ctx_lock().
265 lockdep_assert_held(&ctx->mutex);
269 cpu_function_call(event->cpu, event_function, &efs);
273 if (task == TASK_TOMBSTONE)
277 if (!task_function_call(task, event_function, &efs))
280 raw_spin_lock_irq(&ctx->lock);
282 * Reload the task pointer, it might have been changed by
283 * a concurrent perf_event_context_sched_out().
286 if (task == TASK_TOMBSTONE) {
287 raw_spin_unlock_irq(&ctx->lock);
290 if (ctx->is_active) {
291 raw_spin_unlock_irq(&ctx->lock);
294 func(event, NULL, ctx, data);
295 raw_spin_unlock_irq(&ctx->lock);
299 * Similar to event_function_call() + event_function(), but hard assumes IRQs
300 * are already disabled and we're on the right CPU.
302 static void event_function_local(struct perf_event *event, event_f func, void *data)
304 struct perf_event_context *ctx = event->ctx;
305 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
306 struct task_struct *task = READ_ONCE(ctx->task);
307 struct perf_event_context *task_ctx = NULL;
309 WARN_ON_ONCE(!irqs_disabled());
312 if (task == TASK_TOMBSTONE)
318 perf_ctx_lock(cpuctx, task_ctx);
321 if (task == TASK_TOMBSTONE)
326 * We must be either inactive or active and the right task,
327 * otherwise we're screwed, since we cannot IPI to somewhere
330 if (ctx->is_active) {
331 if (WARN_ON_ONCE(task != current))
334 if (WARN_ON_ONCE(cpuctx->task_ctx != ctx))
338 WARN_ON_ONCE(&cpuctx->ctx != ctx);
341 func(event, cpuctx, ctx, data);
343 perf_ctx_unlock(cpuctx, task_ctx);
346 #define PERF_FLAG_ALL (PERF_FLAG_FD_NO_GROUP |\
347 PERF_FLAG_FD_OUTPUT |\
348 PERF_FLAG_PID_CGROUP |\
349 PERF_FLAG_FD_CLOEXEC)
352 * branch priv levels that need permission checks
354 #define PERF_SAMPLE_BRANCH_PERM_PLM \
355 (PERF_SAMPLE_BRANCH_KERNEL |\
356 PERF_SAMPLE_BRANCH_HV)
359 EVENT_FLEXIBLE = 0x1,
362 /* see ctx_resched() for details */
364 EVENT_ALL = EVENT_FLEXIBLE | EVENT_PINNED,
368 * perf_sched_events : >0 events exist
369 * perf_cgroup_events: >0 per-cpu cgroup events exist on this cpu
372 static void perf_sched_delayed(struct work_struct *work);
373 DEFINE_STATIC_KEY_FALSE(perf_sched_events);
374 static DECLARE_DELAYED_WORK(perf_sched_work, perf_sched_delayed);
375 static DEFINE_MUTEX(perf_sched_mutex);
376 static atomic_t perf_sched_count;
378 static DEFINE_PER_CPU(atomic_t, perf_cgroup_events);
379 static DEFINE_PER_CPU(int, perf_sched_cb_usages);
380 static DEFINE_PER_CPU(struct pmu_event_list, pmu_sb_events);
382 static atomic_t nr_mmap_events __read_mostly;
383 static atomic_t nr_comm_events __read_mostly;
384 static atomic_t nr_namespaces_events __read_mostly;
385 static atomic_t nr_task_events __read_mostly;
386 static atomic_t nr_freq_events __read_mostly;
387 static atomic_t nr_switch_events __read_mostly;
389 static LIST_HEAD(pmus);
390 static DEFINE_MUTEX(pmus_lock);
391 static struct srcu_struct pmus_srcu;
394 * perf event paranoia level:
395 * -1 - not paranoid at all
396 * 0 - disallow raw tracepoint access for unpriv
397 * 1 - disallow cpu events for unpriv
398 * 2 - disallow kernel profiling for unpriv
400 int sysctl_perf_event_paranoid __read_mostly = 2;
402 /* Minimum for 512 kiB + 1 user control page */
403 int sysctl_perf_event_mlock __read_mostly = 512 + (PAGE_SIZE / 1024); /* 'free' kiB per user */
406 * max perf event sample rate
408 #define DEFAULT_MAX_SAMPLE_RATE 100000
409 #define DEFAULT_SAMPLE_PERIOD_NS (NSEC_PER_SEC / DEFAULT_MAX_SAMPLE_RATE)
410 #define DEFAULT_CPU_TIME_MAX_PERCENT 25
412 int sysctl_perf_event_sample_rate __read_mostly = DEFAULT_MAX_SAMPLE_RATE;
414 static int max_samples_per_tick __read_mostly = DIV_ROUND_UP(DEFAULT_MAX_SAMPLE_RATE, HZ);
415 static int perf_sample_period_ns __read_mostly = DEFAULT_SAMPLE_PERIOD_NS;
417 static int perf_sample_allowed_ns __read_mostly =
418 DEFAULT_SAMPLE_PERIOD_NS * DEFAULT_CPU_TIME_MAX_PERCENT / 100;
420 static void update_perf_cpu_limits(void)
422 u64 tmp = perf_sample_period_ns;
424 tmp *= sysctl_perf_cpu_time_max_percent;
425 tmp = div_u64(tmp, 100);
429 WRITE_ONCE(perf_sample_allowed_ns, tmp);
432 static int perf_rotate_context(struct perf_cpu_context *cpuctx);
434 int perf_proc_update_handler(struct ctl_table *table, int write,
435 void __user *buffer, size_t *lenp,
438 int ret = proc_dointvec_minmax(table, write, buffer, lenp, ppos);
444 * If throttling is disabled don't allow the write:
446 if (sysctl_perf_cpu_time_max_percent == 100 ||
447 sysctl_perf_cpu_time_max_percent == 0)
450 max_samples_per_tick = DIV_ROUND_UP(sysctl_perf_event_sample_rate, HZ);
451 perf_sample_period_ns = NSEC_PER_SEC / sysctl_perf_event_sample_rate;
452 update_perf_cpu_limits();
457 int sysctl_perf_cpu_time_max_percent __read_mostly = DEFAULT_CPU_TIME_MAX_PERCENT;
459 int perf_cpu_time_max_percent_handler(struct ctl_table *table, int write,
460 void __user *buffer, size_t *lenp,
463 int ret = proc_dointvec_minmax(table, write, buffer, lenp, ppos);
468 if (sysctl_perf_cpu_time_max_percent == 100 ||
469 sysctl_perf_cpu_time_max_percent == 0) {
471 "perf: Dynamic interrupt throttling disabled, can hang your system!\n");
472 WRITE_ONCE(perf_sample_allowed_ns, 0);
474 update_perf_cpu_limits();
481 * perf samples are done in some very critical code paths (NMIs).
482 * If they take too much CPU time, the system can lock up and not
483 * get any real work done. This will drop the sample rate when
484 * we detect that events are taking too long.
486 #define NR_ACCUMULATED_SAMPLES 128
487 static DEFINE_PER_CPU(u64, running_sample_length);
489 static u64 __report_avg;
490 static u64 __report_allowed;
492 static void perf_duration_warn(struct irq_work *w)
494 printk_ratelimited(KERN_INFO
495 "perf: interrupt took too long (%lld > %lld), lowering "
496 "kernel.perf_event_max_sample_rate to %d\n",
497 __report_avg, __report_allowed,
498 sysctl_perf_event_sample_rate);
501 static DEFINE_IRQ_WORK(perf_duration_work, perf_duration_warn);
503 void perf_sample_event_took(u64 sample_len_ns)
505 u64 max_len = READ_ONCE(perf_sample_allowed_ns);
513 /* Decay the counter by 1 average sample. */
514 running_len = __this_cpu_read(running_sample_length);
515 running_len -= running_len/NR_ACCUMULATED_SAMPLES;
516 running_len += sample_len_ns;
517 __this_cpu_write(running_sample_length, running_len);
520 * Note: this will be biased artifically low until we have
521 * seen NR_ACCUMULATED_SAMPLES. Doing it this way keeps us
522 * from having to maintain a count.
524 avg_len = running_len/NR_ACCUMULATED_SAMPLES;
525 if (avg_len <= max_len)
528 __report_avg = avg_len;
529 __report_allowed = max_len;
532 * Compute a throttle threshold 25% below the current duration.
534 avg_len += avg_len / 4;
535 max = (TICK_NSEC / 100) * sysctl_perf_cpu_time_max_percent;
541 WRITE_ONCE(perf_sample_allowed_ns, avg_len);
542 WRITE_ONCE(max_samples_per_tick, max);
544 sysctl_perf_event_sample_rate = max * HZ;
545 perf_sample_period_ns = NSEC_PER_SEC / sysctl_perf_event_sample_rate;
547 if (!irq_work_queue(&perf_duration_work)) {
548 early_printk("perf: interrupt took too long (%lld > %lld), lowering "
549 "kernel.perf_event_max_sample_rate to %d\n",
550 __report_avg, __report_allowed,
551 sysctl_perf_event_sample_rate);
555 static atomic64_t perf_event_id;
557 static void cpu_ctx_sched_out(struct perf_cpu_context *cpuctx,
558 enum event_type_t event_type);
560 static void cpu_ctx_sched_in(struct perf_cpu_context *cpuctx,
561 enum event_type_t event_type,
562 struct task_struct *task);
564 static void update_context_time(struct perf_event_context *ctx);
565 static u64 perf_event_time(struct perf_event *event);
567 void __weak perf_event_print_debug(void) { }
569 extern __weak const char *perf_pmu_name(void)
574 static inline u64 perf_clock(void)
576 return local_clock();
579 static inline u64 perf_event_clock(struct perf_event *event)
581 return event->clock();
584 #ifdef CONFIG_CGROUP_PERF
587 perf_cgroup_match(struct perf_event *event)
589 struct perf_event_context *ctx = event->ctx;
590 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
592 /* @event doesn't care about cgroup */
596 /* wants specific cgroup scope but @cpuctx isn't associated with any */
601 * Cgroup scoping is recursive. An event enabled for a cgroup is
602 * also enabled for all its descendant cgroups. If @cpuctx's
603 * cgroup is a descendant of @event's (the test covers identity
604 * case), it's a match.
606 return cgroup_is_descendant(cpuctx->cgrp->css.cgroup,
607 event->cgrp->css.cgroup);
610 static inline void perf_detach_cgroup(struct perf_event *event)
612 css_put(&event->cgrp->css);
616 static inline int is_cgroup_event(struct perf_event *event)
618 return event->cgrp != NULL;
621 static inline u64 perf_cgroup_event_time(struct perf_event *event)
623 struct perf_cgroup_info *t;
625 t = per_cpu_ptr(event->cgrp->info, event->cpu);
629 static inline void __update_cgrp_time(struct perf_cgroup *cgrp)
631 struct perf_cgroup_info *info;
636 info = this_cpu_ptr(cgrp->info);
638 info->time += now - info->timestamp;
639 info->timestamp = now;
642 static inline void update_cgrp_time_from_cpuctx(struct perf_cpu_context *cpuctx)
644 struct perf_cgroup *cgrp_out = cpuctx->cgrp;
646 __update_cgrp_time(cgrp_out);
649 static inline void update_cgrp_time_from_event(struct perf_event *event)
651 struct perf_cgroup *cgrp;
654 * ensure we access cgroup data only when needed and
655 * when we know the cgroup is pinned (css_get)
657 if (!is_cgroup_event(event))
660 cgrp = perf_cgroup_from_task(current, event->ctx);
662 * Do not update time when cgroup is not active
664 if (cgrp == event->cgrp)
665 __update_cgrp_time(event->cgrp);
669 perf_cgroup_set_timestamp(struct task_struct *task,
670 struct perf_event_context *ctx)
672 struct perf_cgroup *cgrp;
673 struct perf_cgroup_info *info;
676 * ctx->lock held by caller
677 * ensure we do not access cgroup data
678 * unless we have the cgroup pinned (css_get)
680 if (!task || !ctx->nr_cgroups)
683 cgrp = perf_cgroup_from_task(task, ctx);
684 info = this_cpu_ptr(cgrp->info);
685 info->timestamp = ctx->timestamp;
688 static DEFINE_PER_CPU(struct list_head, cgrp_cpuctx_list);
690 #define PERF_CGROUP_SWOUT 0x1 /* cgroup switch out every event */
691 #define PERF_CGROUP_SWIN 0x2 /* cgroup switch in events based on task */
694 * reschedule events based on the cgroup constraint of task.
696 * mode SWOUT : schedule out everything
697 * mode SWIN : schedule in based on cgroup for next
699 static void perf_cgroup_switch(struct task_struct *task, int mode)
701 struct perf_cpu_context *cpuctx;
702 struct list_head *list;
706 * Disable interrupts and preemption to avoid this CPU's
707 * cgrp_cpuctx_entry to change under us.
709 local_irq_save(flags);
711 list = this_cpu_ptr(&cgrp_cpuctx_list);
712 list_for_each_entry(cpuctx, list, cgrp_cpuctx_entry) {
713 WARN_ON_ONCE(cpuctx->ctx.nr_cgroups == 0);
715 perf_ctx_lock(cpuctx, cpuctx->task_ctx);
716 perf_pmu_disable(cpuctx->ctx.pmu);
718 if (mode & PERF_CGROUP_SWOUT) {
719 cpu_ctx_sched_out(cpuctx, EVENT_ALL);
721 * must not be done before ctxswout due
722 * to event_filter_match() in event_sched_out()
727 if (mode & PERF_CGROUP_SWIN) {
728 WARN_ON_ONCE(cpuctx->cgrp);
730 * set cgrp before ctxsw in to allow
731 * event_filter_match() to not have to pass
733 * we pass the cpuctx->ctx to perf_cgroup_from_task()
734 * because cgorup events are only per-cpu
736 cpuctx->cgrp = perf_cgroup_from_task(task,
738 cpu_ctx_sched_in(cpuctx, EVENT_ALL, task);
740 perf_pmu_enable(cpuctx->ctx.pmu);
741 perf_ctx_unlock(cpuctx, cpuctx->task_ctx);
744 local_irq_restore(flags);
747 static inline void perf_cgroup_sched_out(struct task_struct *task,
748 struct task_struct *next)
750 struct perf_cgroup *cgrp1;
751 struct perf_cgroup *cgrp2 = NULL;
755 * we come here when we know perf_cgroup_events > 0
756 * we do not need to pass the ctx here because we know
757 * we are holding the rcu lock
759 cgrp1 = perf_cgroup_from_task(task, NULL);
760 cgrp2 = perf_cgroup_from_task(next, NULL);
763 * only schedule out current cgroup events if we know
764 * that we are switching to a different cgroup. Otherwise,
765 * do no touch the cgroup events.
768 perf_cgroup_switch(task, PERF_CGROUP_SWOUT);
773 static inline void perf_cgroup_sched_in(struct task_struct *prev,
774 struct task_struct *task)
776 struct perf_cgroup *cgrp1;
777 struct perf_cgroup *cgrp2 = NULL;
781 * we come here when we know perf_cgroup_events > 0
782 * we do not need to pass the ctx here because we know
783 * we are holding the rcu lock
785 cgrp1 = perf_cgroup_from_task(task, NULL);
786 cgrp2 = perf_cgroup_from_task(prev, NULL);
789 * only need to schedule in cgroup events if we are changing
790 * cgroup during ctxsw. Cgroup events were not scheduled
791 * out of ctxsw out if that was not the case.
794 perf_cgroup_switch(task, PERF_CGROUP_SWIN);
799 static inline int perf_cgroup_connect(int fd, struct perf_event *event,
800 struct perf_event_attr *attr,
801 struct perf_event *group_leader)
803 struct perf_cgroup *cgrp;
804 struct cgroup_subsys_state *css;
805 struct fd f = fdget(fd);
811 css = css_tryget_online_from_dir(f.file->f_path.dentry,
812 &perf_event_cgrp_subsys);
818 cgrp = container_of(css, struct perf_cgroup, css);
822 * all events in a group must monitor
823 * the same cgroup because a task belongs
824 * to only one perf cgroup at a time
826 if (group_leader && group_leader->cgrp != cgrp) {
827 perf_detach_cgroup(event);
836 perf_cgroup_set_shadow_time(struct perf_event *event, u64 now)
838 struct perf_cgroup_info *t;
839 t = per_cpu_ptr(event->cgrp->info, event->cpu);
840 event->shadow_ctx_time = now - t->timestamp;
844 perf_cgroup_defer_enabled(struct perf_event *event)
847 * when the current task's perf cgroup does not match
848 * the event's, we need to remember to call the
849 * perf_mark_enable() function the first time a task with
850 * a matching perf cgroup is scheduled in.
852 if (is_cgroup_event(event) && !perf_cgroup_match(event))
853 event->cgrp_defer_enabled = 1;
857 perf_cgroup_mark_enabled(struct perf_event *event,
858 struct perf_event_context *ctx)
860 struct perf_event *sub;
861 u64 tstamp = perf_event_time(event);
863 if (!event->cgrp_defer_enabled)
866 event->cgrp_defer_enabled = 0;
868 event->tstamp_enabled = tstamp - event->total_time_enabled;
869 list_for_each_entry(sub, &event->sibling_list, group_entry) {
870 if (sub->state >= PERF_EVENT_STATE_INACTIVE) {
871 sub->tstamp_enabled = tstamp - sub->total_time_enabled;
872 sub->cgrp_defer_enabled = 0;
878 * Update cpuctx->cgrp so that it is set when first cgroup event is added and
879 * cleared when last cgroup event is removed.
882 list_update_cgroup_event(struct perf_event *event,
883 struct perf_event_context *ctx, bool add)
885 struct perf_cpu_context *cpuctx;
886 struct list_head *cpuctx_entry;
888 if (!is_cgroup_event(event))
891 if (add && ctx->nr_cgroups++)
893 else if (!add && --ctx->nr_cgroups)
896 * Because cgroup events are always per-cpu events,
897 * this will always be called from the right CPU.
899 cpuctx = __get_cpu_context(ctx);
900 cpuctx_entry = &cpuctx->cgrp_cpuctx_entry;
901 /* cpuctx->cgrp is NULL unless a cgroup event is active in this CPU .*/
903 list_add(cpuctx_entry, this_cpu_ptr(&cgrp_cpuctx_list));
904 if (perf_cgroup_from_task(current, ctx) == event->cgrp)
905 cpuctx->cgrp = event->cgrp;
907 list_del(cpuctx_entry);
912 #else /* !CONFIG_CGROUP_PERF */
915 perf_cgroup_match(struct perf_event *event)
920 static inline void perf_detach_cgroup(struct perf_event *event)
923 static inline int is_cgroup_event(struct perf_event *event)
928 static inline u64 perf_cgroup_event_cgrp_time(struct perf_event *event)
933 static inline void update_cgrp_time_from_event(struct perf_event *event)
937 static inline void update_cgrp_time_from_cpuctx(struct perf_cpu_context *cpuctx)
941 static inline void perf_cgroup_sched_out(struct task_struct *task,
942 struct task_struct *next)
946 static inline void perf_cgroup_sched_in(struct task_struct *prev,
947 struct task_struct *task)
951 static inline int perf_cgroup_connect(pid_t pid, struct perf_event *event,
952 struct perf_event_attr *attr,
953 struct perf_event *group_leader)
959 perf_cgroup_set_timestamp(struct task_struct *task,
960 struct perf_event_context *ctx)
965 perf_cgroup_switch(struct task_struct *task, struct task_struct *next)
970 perf_cgroup_set_shadow_time(struct perf_event *event, u64 now)
974 static inline u64 perf_cgroup_event_time(struct perf_event *event)
980 perf_cgroup_defer_enabled(struct perf_event *event)
985 perf_cgroup_mark_enabled(struct perf_event *event,
986 struct perf_event_context *ctx)
991 list_update_cgroup_event(struct perf_event *event,
992 struct perf_event_context *ctx, bool add)
999 * set default to be dependent on timer tick just
1000 * like original code
1002 #define PERF_CPU_HRTIMER (1000 / HZ)
1004 * function must be called with interrupts disabled
1006 static enum hrtimer_restart perf_mux_hrtimer_handler(struct hrtimer *hr)
1008 struct perf_cpu_context *cpuctx;
1011 WARN_ON(!irqs_disabled());
1013 cpuctx = container_of(hr, struct perf_cpu_context, hrtimer);
1014 rotations = perf_rotate_context(cpuctx);
1016 raw_spin_lock(&cpuctx->hrtimer_lock);
1018 hrtimer_forward_now(hr, cpuctx->hrtimer_interval);
1020 cpuctx->hrtimer_active = 0;
1021 raw_spin_unlock(&cpuctx->hrtimer_lock);
1023 return rotations ? HRTIMER_RESTART : HRTIMER_NORESTART;
1026 static void __perf_mux_hrtimer_init(struct perf_cpu_context *cpuctx, int cpu)
1028 struct hrtimer *timer = &cpuctx->hrtimer;
1029 struct pmu *pmu = cpuctx->ctx.pmu;
1032 /* no multiplexing needed for SW PMU */
1033 if (pmu->task_ctx_nr == perf_sw_context)
1037 * check default is sane, if not set then force to
1038 * default interval (1/tick)
1040 interval = pmu->hrtimer_interval_ms;
1042 interval = pmu->hrtimer_interval_ms = PERF_CPU_HRTIMER;
1044 cpuctx->hrtimer_interval = ns_to_ktime(NSEC_PER_MSEC * interval);
1046 raw_spin_lock_init(&cpuctx->hrtimer_lock);
1047 hrtimer_init(timer, CLOCK_MONOTONIC, HRTIMER_MODE_ABS_PINNED);
1048 timer->function = perf_mux_hrtimer_handler;
1051 static int perf_mux_hrtimer_restart(struct perf_cpu_context *cpuctx)
1053 struct hrtimer *timer = &cpuctx->hrtimer;
1054 struct pmu *pmu = cpuctx->ctx.pmu;
1055 unsigned long flags;
1057 /* not for SW PMU */
1058 if (pmu->task_ctx_nr == perf_sw_context)
1061 raw_spin_lock_irqsave(&cpuctx->hrtimer_lock, flags);
1062 if (!cpuctx->hrtimer_active) {
1063 cpuctx->hrtimer_active = 1;
1064 hrtimer_forward_now(timer, cpuctx->hrtimer_interval);
1065 hrtimer_start_expires(timer, HRTIMER_MODE_ABS_PINNED);
1067 raw_spin_unlock_irqrestore(&cpuctx->hrtimer_lock, flags);
1072 void perf_pmu_disable(struct pmu *pmu)
1074 int *count = this_cpu_ptr(pmu->pmu_disable_count);
1076 pmu->pmu_disable(pmu);
1079 void perf_pmu_enable(struct pmu *pmu)
1081 int *count = this_cpu_ptr(pmu->pmu_disable_count);
1083 pmu->pmu_enable(pmu);
1086 static DEFINE_PER_CPU(struct list_head, active_ctx_list);
1089 * perf_event_ctx_activate(), perf_event_ctx_deactivate(), and
1090 * perf_event_task_tick() are fully serialized because they're strictly cpu
1091 * affine and perf_event_ctx{activate,deactivate} are called with IRQs
1092 * disabled, while perf_event_task_tick is called from IRQ context.
1094 static void perf_event_ctx_activate(struct perf_event_context *ctx)
1096 struct list_head *head = this_cpu_ptr(&active_ctx_list);
1098 WARN_ON(!irqs_disabled());
1100 WARN_ON(!list_empty(&ctx->active_ctx_list));
1102 list_add(&ctx->active_ctx_list, head);
1105 static void perf_event_ctx_deactivate(struct perf_event_context *ctx)
1107 WARN_ON(!irqs_disabled());
1109 WARN_ON(list_empty(&ctx->active_ctx_list));
1111 list_del_init(&ctx->active_ctx_list);
1114 static void get_ctx(struct perf_event_context *ctx)
1116 WARN_ON(!atomic_inc_not_zero(&ctx->refcount));
1119 static void free_ctx(struct rcu_head *head)
1121 struct perf_event_context *ctx;
1123 ctx = container_of(head, struct perf_event_context, rcu_head);
1124 kfree(ctx->task_ctx_data);
1128 static void put_ctx(struct perf_event_context *ctx)
1130 if (atomic_dec_and_test(&ctx->refcount)) {
1131 if (ctx->parent_ctx)
1132 put_ctx(ctx->parent_ctx);
1133 if (ctx->task && ctx->task != TASK_TOMBSTONE)
1134 put_task_struct(ctx->task);
1135 call_rcu(&ctx->rcu_head, free_ctx);
1140 * Because of perf_event::ctx migration in sys_perf_event_open::move_group and
1141 * perf_pmu_migrate_context() we need some magic.
1143 * Those places that change perf_event::ctx will hold both
1144 * perf_event_ctx::mutex of the 'old' and 'new' ctx value.
1146 * Lock ordering is by mutex address. There are two other sites where
1147 * perf_event_context::mutex nests and those are:
1149 * - perf_event_exit_task_context() [ child , 0 ]
1150 * perf_event_exit_event()
1151 * put_event() [ parent, 1 ]
1153 * - perf_event_init_context() [ parent, 0 ]
1154 * inherit_task_group()
1157 * perf_event_alloc()
1159 * perf_try_init_event() [ child , 1 ]
1161 * While it appears there is an obvious deadlock here -- the parent and child
1162 * nesting levels are inverted between the two. This is in fact safe because
1163 * life-time rules separate them. That is an exiting task cannot fork, and a
1164 * spawning task cannot (yet) exit.
1166 * But remember that that these are parent<->child context relations, and
1167 * migration does not affect children, therefore these two orderings should not
1170 * The change in perf_event::ctx does not affect children (as claimed above)
1171 * because the sys_perf_event_open() case will install a new event and break
1172 * the ctx parent<->child relation, and perf_pmu_migrate_context() is only
1173 * concerned with cpuctx and that doesn't have children.
1175 * The places that change perf_event::ctx will issue:
1177 * perf_remove_from_context();
1178 * synchronize_rcu();
1179 * perf_install_in_context();
1181 * to affect the change. The remove_from_context() + synchronize_rcu() should
1182 * quiesce the event, after which we can install it in the new location. This
1183 * means that only external vectors (perf_fops, prctl) can perturb the event
1184 * while in transit. Therefore all such accessors should also acquire
1185 * perf_event_context::mutex to serialize against this.
1187 * However; because event->ctx can change while we're waiting to acquire
1188 * ctx->mutex we must be careful and use the below perf_event_ctx_lock()
1193 * task_struct::perf_event_mutex
1194 * perf_event_context::mutex
1195 * perf_event::child_mutex;
1196 * perf_event_context::lock
1197 * perf_event::mmap_mutex
1200 static struct perf_event_context *
1201 perf_event_ctx_lock_nested(struct perf_event *event, int nesting)
1203 struct perf_event_context *ctx;
1207 ctx = ACCESS_ONCE(event->ctx);
1208 if (!atomic_inc_not_zero(&ctx->refcount)) {
1214 mutex_lock_nested(&ctx->mutex, nesting);
1215 if (event->ctx != ctx) {
1216 mutex_unlock(&ctx->mutex);
1224 static inline struct perf_event_context *
1225 perf_event_ctx_lock(struct perf_event *event)
1227 return perf_event_ctx_lock_nested(event, 0);
1230 static void perf_event_ctx_unlock(struct perf_event *event,
1231 struct perf_event_context *ctx)
1233 mutex_unlock(&ctx->mutex);
1238 * This must be done under the ctx->lock, such as to serialize against
1239 * context_equiv(), therefore we cannot call put_ctx() since that might end up
1240 * calling scheduler related locks and ctx->lock nests inside those.
1242 static __must_check struct perf_event_context *
1243 unclone_ctx(struct perf_event_context *ctx)
1245 struct perf_event_context *parent_ctx = ctx->parent_ctx;
1247 lockdep_assert_held(&ctx->lock);
1250 ctx->parent_ctx = NULL;
1256 static u32 perf_event_pid(struct perf_event *event, struct task_struct *p)
1259 * only top level events have the pid namespace they were created in
1262 event = event->parent;
1264 return task_tgid_nr_ns(p, event->ns);
1267 static u32 perf_event_tid(struct perf_event *event, struct task_struct *p)
1270 * only top level events have the pid namespace they were created in
1273 event = event->parent;
1275 return task_pid_nr_ns(p, event->ns);
1279 * If we inherit events we want to return the parent event id
1282 static u64 primary_event_id(struct perf_event *event)
1287 id = event->parent->id;
1293 * Get the perf_event_context for a task and lock it.
1295 * This has to cope with with the fact that until it is locked,
1296 * the context could get moved to another task.
1298 static struct perf_event_context *
1299 perf_lock_task_context(struct task_struct *task, int ctxn, unsigned long *flags)
1301 struct perf_event_context *ctx;
1305 * One of the few rules of preemptible RCU is that one cannot do
1306 * rcu_read_unlock() while holding a scheduler (or nested) lock when
1307 * part of the read side critical section was irqs-enabled -- see
1308 * rcu_read_unlock_special().
1310 * Since ctx->lock nests under rq->lock we must ensure the entire read
1311 * side critical section has interrupts disabled.
1313 local_irq_save(*flags);
1315 ctx = rcu_dereference(task->perf_event_ctxp[ctxn]);
1318 * If this context is a clone of another, it might
1319 * get swapped for another underneath us by
1320 * perf_event_task_sched_out, though the
1321 * rcu_read_lock() protects us from any context
1322 * getting freed. Lock the context and check if it
1323 * got swapped before we could get the lock, and retry
1324 * if so. If we locked the right context, then it
1325 * can't get swapped on us any more.
1327 raw_spin_lock(&ctx->lock);
1328 if (ctx != rcu_dereference(task->perf_event_ctxp[ctxn])) {
1329 raw_spin_unlock(&ctx->lock);
1331 local_irq_restore(*flags);
1335 if (ctx->task == TASK_TOMBSTONE ||
1336 !atomic_inc_not_zero(&ctx->refcount)) {
1337 raw_spin_unlock(&ctx->lock);
1340 WARN_ON_ONCE(ctx->task != task);
1345 local_irq_restore(*flags);
1350 * Get the context for a task and increment its pin_count so it
1351 * can't get swapped to another task. This also increments its
1352 * reference count so that the context can't get freed.
1354 static struct perf_event_context *
1355 perf_pin_task_context(struct task_struct *task, int ctxn)
1357 struct perf_event_context *ctx;
1358 unsigned long flags;
1360 ctx = perf_lock_task_context(task, ctxn, &flags);
1363 raw_spin_unlock_irqrestore(&ctx->lock, flags);
1368 static void perf_unpin_context(struct perf_event_context *ctx)
1370 unsigned long flags;
1372 raw_spin_lock_irqsave(&ctx->lock, flags);
1374 raw_spin_unlock_irqrestore(&ctx->lock, flags);
1378 * Update the record of the current time in a context.
1380 static void update_context_time(struct perf_event_context *ctx)
1382 u64 now = perf_clock();
1384 ctx->time += now - ctx->timestamp;
1385 ctx->timestamp = now;
1388 static u64 perf_event_time(struct perf_event *event)
1390 struct perf_event_context *ctx = event->ctx;
1392 if (is_cgroup_event(event))
1393 return perf_cgroup_event_time(event);
1395 return ctx ? ctx->time : 0;
1399 * Update the total_time_enabled and total_time_running fields for a event.
1401 static void update_event_times(struct perf_event *event)
1403 struct perf_event_context *ctx = event->ctx;
1406 lockdep_assert_held(&ctx->lock);
1408 if (event->state < PERF_EVENT_STATE_INACTIVE ||
1409 event->group_leader->state < PERF_EVENT_STATE_INACTIVE)
1413 * in cgroup mode, time_enabled represents
1414 * the time the event was enabled AND active
1415 * tasks were in the monitored cgroup. This is
1416 * independent of the activity of the context as
1417 * there may be a mix of cgroup and non-cgroup events.
1419 * That is why we treat cgroup events differently
1422 if (is_cgroup_event(event))
1423 run_end = perf_cgroup_event_time(event);
1424 else if (ctx->is_active)
1425 run_end = ctx->time;
1427 run_end = event->tstamp_stopped;
1429 event->total_time_enabled = run_end - event->tstamp_enabled;
1431 if (event->state == PERF_EVENT_STATE_INACTIVE)
1432 run_end = event->tstamp_stopped;
1434 run_end = perf_event_time(event);
1436 event->total_time_running = run_end - event->tstamp_running;
1441 * Update total_time_enabled and total_time_running for all events in a group.
1443 static void update_group_times(struct perf_event *leader)
1445 struct perf_event *event;
1447 update_event_times(leader);
1448 list_for_each_entry(event, &leader->sibling_list, group_entry)
1449 update_event_times(event);
1452 static enum event_type_t get_event_type(struct perf_event *event)
1454 struct perf_event_context *ctx = event->ctx;
1455 enum event_type_t event_type;
1457 lockdep_assert_held(&ctx->lock);
1459 event_type = event->attr.pinned ? EVENT_PINNED : EVENT_FLEXIBLE;
1461 event_type |= EVENT_CPU;
1466 static struct list_head *
1467 ctx_group_list(struct perf_event *event, struct perf_event_context *ctx)
1469 if (event->attr.pinned)
1470 return &ctx->pinned_groups;
1472 return &ctx->flexible_groups;
1476 * Add a event from the lists for its context.
1477 * Must be called with ctx->mutex and ctx->lock held.
1480 list_add_event(struct perf_event *event, struct perf_event_context *ctx)
1482 lockdep_assert_held(&ctx->lock);
1484 WARN_ON_ONCE(event->attach_state & PERF_ATTACH_CONTEXT);
1485 event->attach_state |= PERF_ATTACH_CONTEXT;
1488 * If we're a stand alone event or group leader, we go to the context
1489 * list, group events are kept attached to the group so that
1490 * perf_group_detach can, at all times, locate all siblings.
1492 if (event->group_leader == event) {
1493 struct list_head *list;
1495 event->group_caps = event->event_caps;
1497 list = ctx_group_list(event, ctx);
1498 list_add_tail(&event->group_entry, list);
1501 list_update_cgroup_event(event, ctx, true);
1503 list_add_rcu(&event->event_entry, &ctx->event_list);
1505 if (event->attr.inherit_stat)
1512 * Initialize event state based on the perf_event_attr::disabled.
1514 static inline void perf_event__state_init(struct perf_event *event)
1516 event->state = event->attr.disabled ? PERF_EVENT_STATE_OFF :
1517 PERF_EVENT_STATE_INACTIVE;
1520 static void __perf_event_read_size(struct perf_event *event, int nr_siblings)
1522 int entry = sizeof(u64); /* value */
1526 if (event->attr.read_format & PERF_FORMAT_TOTAL_TIME_ENABLED)
1527 size += sizeof(u64);
1529 if (event->attr.read_format & PERF_FORMAT_TOTAL_TIME_RUNNING)
1530 size += sizeof(u64);
1532 if (event->attr.read_format & PERF_FORMAT_ID)
1533 entry += sizeof(u64);
1535 if (event->attr.read_format & PERF_FORMAT_GROUP) {
1537 size += sizeof(u64);
1541 event->read_size = size;
1544 static void __perf_event_header_size(struct perf_event *event, u64 sample_type)
1546 struct perf_sample_data *data;
1549 if (sample_type & PERF_SAMPLE_IP)
1550 size += sizeof(data->ip);
1552 if (sample_type & PERF_SAMPLE_ADDR)
1553 size += sizeof(data->addr);
1555 if (sample_type & PERF_SAMPLE_PERIOD)
1556 size += sizeof(data->period);
1558 if (sample_type & PERF_SAMPLE_WEIGHT)
1559 size += sizeof(data->weight);
1561 if (sample_type & PERF_SAMPLE_READ)
1562 size += event->read_size;
1564 if (sample_type & PERF_SAMPLE_DATA_SRC)
1565 size += sizeof(data->data_src.val);
1567 if (sample_type & PERF_SAMPLE_TRANSACTION)
1568 size += sizeof(data->txn);
1570 event->header_size = size;
1574 * Called at perf_event creation and when events are attached/detached from a
1577 static void perf_event__header_size(struct perf_event *event)
1579 __perf_event_read_size(event,
1580 event->group_leader->nr_siblings);
1581 __perf_event_header_size(event, event->attr.sample_type);
1584 static void perf_event__id_header_size(struct perf_event *event)
1586 struct perf_sample_data *data;
1587 u64 sample_type = event->attr.sample_type;
1590 if (sample_type & PERF_SAMPLE_TID)
1591 size += sizeof(data->tid_entry);
1593 if (sample_type & PERF_SAMPLE_TIME)
1594 size += sizeof(data->time);
1596 if (sample_type & PERF_SAMPLE_IDENTIFIER)
1597 size += sizeof(data->id);
1599 if (sample_type & PERF_SAMPLE_ID)
1600 size += sizeof(data->id);
1602 if (sample_type & PERF_SAMPLE_STREAM_ID)
1603 size += sizeof(data->stream_id);
1605 if (sample_type & PERF_SAMPLE_CPU)
1606 size += sizeof(data->cpu_entry);
1608 event->id_header_size = size;
1611 static bool perf_event_validate_size(struct perf_event *event)
1614 * The values computed here will be over-written when we actually
1617 __perf_event_read_size(event, event->group_leader->nr_siblings + 1);
1618 __perf_event_header_size(event, event->attr.sample_type & ~PERF_SAMPLE_READ);
1619 perf_event__id_header_size(event);
1622 * Sum the lot; should not exceed the 64k limit we have on records.
1623 * Conservative limit to allow for callchains and other variable fields.
1625 if (event->read_size + event->header_size +
1626 event->id_header_size + sizeof(struct perf_event_header) >= 16*1024)
1632 static void perf_group_attach(struct perf_event *event)
1634 struct perf_event *group_leader = event->group_leader, *pos;
1636 lockdep_assert_held(&event->ctx->lock);
1639 * We can have double attach due to group movement in perf_event_open.
1641 if (event->attach_state & PERF_ATTACH_GROUP)
1644 event->attach_state |= PERF_ATTACH_GROUP;
1646 if (group_leader == event)
1649 WARN_ON_ONCE(group_leader->ctx != event->ctx);
1651 group_leader->group_caps &= event->event_caps;
1653 list_add_tail(&event->group_entry, &group_leader->sibling_list);
1654 group_leader->nr_siblings++;
1656 perf_event__header_size(group_leader);
1658 list_for_each_entry(pos, &group_leader->sibling_list, group_entry)
1659 perf_event__header_size(pos);
1663 * Remove a event from the lists for its context.
1664 * Must be called with ctx->mutex and ctx->lock held.
1667 list_del_event(struct perf_event *event, struct perf_event_context *ctx)
1669 WARN_ON_ONCE(event->ctx != ctx);
1670 lockdep_assert_held(&ctx->lock);
1673 * We can have double detach due to exit/hot-unplug + close.
1675 if (!(event->attach_state & PERF_ATTACH_CONTEXT))
1678 event->attach_state &= ~PERF_ATTACH_CONTEXT;
1680 list_update_cgroup_event(event, ctx, false);
1683 if (event->attr.inherit_stat)
1686 list_del_rcu(&event->event_entry);
1688 if (event->group_leader == event)
1689 list_del_init(&event->group_entry);
1691 update_group_times(event);
1694 * If event was in error state, then keep it
1695 * that way, otherwise bogus counts will be
1696 * returned on read(). The only way to get out
1697 * of error state is by explicit re-enabling
1700 if (event->state > PERF_EVENT_STATE_OFF)
1701 event->state = PERF_EVENT_STATE_OFF;
1706 static void perf_group_detach(struct perf_event *event)
1708 struct perf_event *sibling, *tmp;
1709 struct list_head *list = NULL;
1711 lockdep_assert_held(&event->ctx->lock);
1714 * We can have double detach due to exit/hot-unplug + close.
1716 if (!(event->attach_state & PERF_ATTACH_GROUP))
1719 event->attach_state &= ~PERF_ATTACH_GROUP;
1722 * If this is a sibling, remove it from its group.
1724 if (event->group_leader != event) {
1725 list_del_init(&event->group_entry);
1726 event->group_leader->nr_siblings--;
1730 if (!list_empty(&event->group_entry))
1731 list = &event->group_entry;
1734 * If this was a group event with sibling events then
1735 * upgrade the siblings to singleton events by adding them
1736 * to whatever list we are on.
1738 list_for_each_entry_safe(sibling, tmp, &event->sibling_list, group_entry) {
1740 list_move_tail(&sibling->group_entry, list);
1741 sibling->group_leader = sibling;
1743 /* Inherit group flags from the previous leader */
1744 sibling->group_caps = event->group_caps;
1746 WARN_ON_ONCE(sibling->ctx != event->ctx);
1750 perf_event__header_size(event->group_leader);
1752 list_for_each_entry(tmp, &event->group_leader->sibling_list, group_entry)
1753 perf_event__header_size(tmp);
1756 static bool is_orphaned_event(struct perf_event *event)
1758 return event->state == PERF_EVENT_STATE_DEAD;
1761 static inline int __pmu_filter_match(struct perf_event *event)
1763 struct pmu *pmu = event->pmu;
1764 return pmu->filter_match ? pmu->filter_match(event) : 1;
1768 * Check whether we should attempt to schedule an event group based on
1769 * PMU-specific filtering. An event group can consist of HW and SW events,
1770 * potentially with a SW leader, so we must check all the filters, to
1771 * determine whether a group is schedulable:
1773 static inline int pmu_filter_match(struct perf_event *event)
1775 struct perf_event *child;
1777 if (!__pmu_filter_match(event))
1780 list_for_each_entry(child, &event->sibling_list, group_entry) {
1781 if (!__pmu_filter_match(child))
1789 event_filter_match(struct perf_event *event)
1791 return (event->cpu == -1 || event->cpu == smp_processor_id()) &&
1792 perf_cgroup_match(event) && pmu_filter_match(event);
1796 event_sched_out(struct perf_event *event,
1797 struct perf_cpu_context *cpuctx,
1798 struct perf_event_context *ctx)
1800 u64 tstamp = perf_event_time(event);
1803 WARN_ON_ONCE(event->ctx != ctx);
1804 lockdep_assert_held(&ctx->lock);
1807 * An event which could not be activated because of
1808 * filter mismatch still needs to have its timings
1809 * maintained, otherwise bogus information is return
1810 * via read() for time_enabled, time_running:
1812 if (event->state == PERF_EVENT_STATE_INACTIVE &&
1813 !event_filter_match(event)) {
1814 delta = tstamp - event->tstamp_stopped;
1815 event->tstamp_running += delta;
1816 event->tstamp_stopped = tstamp;
1819 if (event->state != PERF_EVENT_STATE_ACTIVE)
1822 perf_pmu_disable(event->pmu);
1824 event->tstamp_stopped = tstamp;
1825 event->pmu->del(event, 0);
1827 event->state = PERF_EVENT_STATE_INACTIVE;
1828 if (event->pending_disable) {
1829 event->pending_disable = 0;
1830 event->state = PERF_EVENT_STATE_OFF;
1833 if (!is_software_event(event))
1834 cpuctx->active_oncpu--;
1835 if (!--ctx->nr_active)
1836 perf_event_ctx_deactivate(ctx);
1837 if (event->attr.freq && event->attr.sample_freq)
1839 if (event->attr.exclusive || !cpuctx->active_oncpu)
1840 cpuctx->exclusive = 0;
1842 perf_pmu_enable(event->pmu);
1846 group_sched_out(struct perf_event *group_event,
1847 struct perf_cpu_context *cpuctx,
1848 struct perf_event_context *ctx)
1850 struct perf_event *event;
1851 int state = group_event->state;
1853 perf_pmu_disable(ctx->pmu);
1855 event_sched_out(group_event, cpuctx, ctx);
1858 * Schedule out siblings (if any):
1860 list_for_each_entry(event, &group_event->sibling_list, group_entry)
1861 event_sched_out(event, cpuctx, ctx);
1863 perf_pmu_enable(ctx->pmu);
1865 if (state == PERF_EVENT_STATE_ACTIVE && group_event->attr.exclusive)
1866 cpuctx->exclusive = 0;
1869 #define DETACH_GROUP 0x01UL
1872 * Cross CPU call to remove a performance event
1874 * We disable the event on the hardware level first. After that we
1875 * remove it from the context list.
1878 __perf_remove_from_context(struct perf_event *event,
1879 struct perf_cpu_context *cpuctx,
1880 struct perf_event_context *ctx,
1883 unsigned long flags = (unsigned long)info;
1885 event_sched_out(event, cpuctx, ctx);
1886 if (flags & DETACH_GROUP)
1887 perf_group_detach(event);
1888 list_del_event(event, ctx);
1890 if (!ctx->nr_events && ctx->is_active) {
1893 WARN_ON_ONCE(cpuctx->task_ctx != ctx);
1894 cpuctx->task_ctx = NULL;
1900 * Remove the event from a task's (or a CPU's) list of events.
1902 * If event->ctx is a cloned context, callers must make sure that
1903 * every task struct that event->ctx->task could possibly point to
1904 * remains valid. This is OK when called from perf_release since
1905 * that only calls us on the top-level context, which can't be a clone.
1906 * When called from perf_event_exit_task, it's OK because the
1907 * context has been detached from its task.
1909 static void perf_remove_from_context(struct perf_event *event, unsigned long flags)
1911 struct perf_event_context *ctx = event->ctx;
1913 lockdep_assert_held(&ctx->mutex);
1915 event_function_call(event, __perf_remove_from_context, (void *)flags);
1918 * The above event_function_call() can NO-OP when it hits
1919 * TASK_TOMBSTONE. In that case we must already have been detached
1920 * from the context (by perf_event_exit_event()) but the grouping
1921 * might still be in-tact.
1923 WARN_ON_ONCE(event->attach_state & PERF_ATTACH_CONTEXT);
1924 if ((flags & DETACH_GROUP) &&
1925 (event->attach_state & PERF_ATTACH_GROUP)) {
1927 * Since in that case we cannot possibly be scheduled, simply
1930 raw_spin_lock_irq(&ctx->lock);
1931 perf_group_detach(event);
1932 raw_spin_unlock_irq(&ctx->lock);
1937 * Cross CPU call to disable a performance event
1939 static void __perf_event_disable(struct perf_event *event,
1940 struct perf_cpu_context *cpuctx,
1941 struct perf_event_context *ctx,
1944 if (event->state < PERF_EVENT_STATE_INACTIVE)
1947 update_context_time(ctx);
1948 update_cgrp_time_from_event(event);
1949 update_group_times(event);
1950 if (event == event->group_leader)
1951 group_sched_out(event, cpuctx, ctx);
1953 event_sched_out(event, cpuctx, ctx);
1954 event->state = PERF_EVENT_STATE_OFF;
1960 * If event->ctx is a cloned context, callers must make sure that
1961 * every task struct that event->ctx->task could possibly point to
1962 * remains valid. This condition is satisifed when called through
1963 * perf_event_for_each_child or perf_event_for_each because they
1964 * hold the top-level event's child_mutex, so any descendant that
1965 * goes to exit will block in perf_event_exit_event().
1967 * When called from perf_pending_event it's OK because event->ctx
1968 * is the current context on this CPU and preemption is disabled,
1969 * hence we can't get into perf_event_task_sched_out for this context.
1971 static void _perf_event_disable(struct perf_event *event)
1973 struct perf_event_context *ctx = event->ctx;
1975 raw_spin_lock_irq(&ctx->lock);
1976 if (event->state <= PERF_EVENT_STATE_OFF) {
1977 raw_spin_unlock_irq(&ctx->lock);
1980 raw_spin_unlock_irq(&ctx->lock);
1982 event_function_call(event, __perf_event_disable, NULL);
1985 void perf_event_disable_local(struct perf_event *event)
1987 event_function_local(event, __perf_event_disable, NULL);
1991 * Strictly speaking kernel users cannot create groups and therefore this
1992 * interface does not need the perf_event_ctx_lock() magic.
1994 void perf_event_disable(struct perf_event *event)
1996 struct perf_event_context *ctx;
1998 ctx = perf_event_ctx_lock(event);
1999 _perf_event_disable(event);
2000 perf_event_ctx_unlock(event, ctx);
2002 EXPORT_SYMBOL_GPL(perf_event_disable);
2004 void perf_event_disable_inatomic(struct perf_event *event)
2006 event->pending_disable = 1;
2007 irq_work_queue(&event->pending);
2010 static void perf_set_shadow_time(struct perf_event *event,
2011 struct perf_event_context *ctx,
2015 * use the correct time source for the time snapshot
2017 * We could get by without this by leveraging the
2018 * fact that to get to this function, the caller
2019 * has most likely already called update_context_time()
2020 * and update_cgrp_time_xx() and thus both timestamp
2021 * are identical (or very close). Given that tstamp is,
2022 * already adjusted for cgroup, we could say that:
2023 * tstamp - ctx->timestamp
2025 * tstamp - cgrp->timestamp.
2027 * Then, in perf_output_read(), the calculation would
2028 * work with no changes because:
2029 * - event is guaranteed scheduled in
2030 * - no scheduled out in between
2031 * - thus the timestamp would be the same
2033 * But this is a bit hairy.
2035 * So instead, we have an explicit cgroup call to remain
2036 * within the time time source all along. We believe it
2037 * is cleaner and simpler to understand.
2039 if (is_cgroup_event(event))
2040 perf_cgroup_set_shadow_time(event, tstamp);
2042 event->shadow_ctx_time = tstamp - ctx->timestamp;
2045 #define MAX_INTERRUPTS (~0ULL)
2047 static void perf_log_throttle(struct perf_event *event, int enable);
2048 static void perf_log_itrace_start(struct perf_event *event);
2051 event_sched_in(struct perf_event *event,
2052 struct perf_cpu_context *cpuctx,
2053 struct perf_event_context *ctx)
2055 u64 tstamp = perf_event_time(event);
2058 lockdep_assert_held(&ctx->lock);
2060 if (event->state <= PERF_EVENT_STATE_OFF)
2063 WRITE_ONCE(event->oncpu, smp_processor_id());
2065 * Order event::oncpu write to happen before the ACTIVE state
2069 WRITE_ONCE(event->state, PERF_EVENT_STATE_ACTIVE);
2072 * Unthrottle events, since we scheduled we might have missed several
2073 * ticks already, also for a heavily scheduling task there is little
2074 * guarantee it'll get a tick in a timely manner.
2076 if (unlikely(event->hw.interrupts == MAX_INTERRUPTS)) {
2077 perf_log_throttle(event, 1);
2078 event->hw.interrupts = 0;
2082 * The new state must be visible before we turn it on in the hardware:
2086 perf_pmu_disable(event->pmu);
2088 perf_set_shadow_time(event, ctx, tstamp);
2090 perf_log_itrace_start(event);
2092 if (event->pmu->add(event, PERF_EF_START)) {
2093 event->state = PERF_EVENT_STATE_INACTIVE;
2099 event->tstamp_running += tstamp - event->tstamp_stopped;
2101 if (!is_software_event(event))
2102 cpuctx->active_oncpu++;
2103 if (!ctx->nr_active++)
2104 perf_event_ctx_activate(ctx);
2105 if (event->attr.freq && event->attr.sample_freq)
2108 if (event->attr.exclusive)
2109 cpuctx->exclusive = 1;
2112 perf_pmu_enable(event->pmu);
2118 group_sched_in(struct perf_event *group_event,
2119 struct perf_cpu_context *cpuctx,
2120 struct perf_event_context *ctx)
2122 struct perf_event *event, *partial_group = NULL;
2123 struct pmu *pmu = ctx->pmu;
2124 u64 now = ctx->time;
2125 bool simulate = false;
2127 if (group_event->state == PERF_EVENT_STATE_OFF)
2130 pmu->start_txn(pmu, PERF_PMU_TXN_ADD);
2132 if (event_sched_in(group_event, cpuctx, ctx)) {
2133 pmu->cancel_txn(pmu);
2134 perf_mux_hrtimer_restart(cpuctx);
2139 * Schedule in siblings as one group (if any):
2141 list_for_each_entry(event, &group_event->sibling_list, group_entry) {
2142 if (event_sched_in(event, cpuctx, ctx)) {
2143 partial_group = event;
2148 if (!pmu->commit_txn(pmu))
2153 * Groups can be scheduled in as one unit only, so undo any
2154 * partial group before returning:
2155 * The events up to the failed event are scheduled out normally,
2156 * tstamp_stopped will be updated.
2158 * The failed events and the remaining siblings need to have
2159 * their timings updated as if they had gone thru event_sched_in()
2160 * and event_sched_out(). This is required to get consistent timings
2161 * across the group. This also takes care of the case where the group
2162 * could never be scheduled by ensuring tstamp_stopped is set to mark
2163 * the time the event was actually stopped, such that time delta
2164 * calculation in update_event_times() is correct.
2166 list_for_each_entry(event, &group_event->sibling_list, group_entry) {
2167 if (event == partial_group)
2171 event->tstamp_running += now - event->tstamp_stopped;
2172 event->tstamp_stopped = now;
2174 event_sched_out(event, cpuctx, ctx);
2177 event_sched_out(group_event, cpuctx, ctx);
2179 pmu->cancel_txn(pmu);
2181 perf_mux_hrtimer_restart(cpuctx);
2187 * Work out whether we can put this event group on the CPU now.
2189 static int group_can_go_on(struct perf_event *event,
2190 struct perf_cpu_context *cpuctx,
2194 * Groups consisting entirely of software events can always go on.
2196 if (event->group_caps & PERF_EV_CAP_SOFTWARE)
2199 * If an exclusive group is already on, no other hardware
2202 if (cpuctx->exclusive)
2205 * If this group is exclusive and there are already
2206 * events on the CPU, it can't go on.
2208 if (event->attr.exclusive && cpuctx->active_oncpu)
2211 * Otherwise, try to add it if all previous groups were able
2217 static void add_event_to_ctx(struct perf_event *event,
2218 struct perf_event_context *ctx)
2220 u64 tstamp = perf_event_time(event);
2222 list_add_event(event, ctx);
2223 perf_group_attach(event);
2224 event->tstamp_enabled = tstamp;
2225 event->tstamp_running = tstamp;
2226 event->tstamp_stopped = tstamp;
2229 static void ctx_sched_out(struct perf_event_context *ctx,
2230 struct perf_cpu_context *cpuctx,
2231 enum event_type_t event_type);
2233 ctx_sched_in(struct perf_event_context *ctx,
2234 struct perf_cpu_context *cpuctx,
2235 enum event_type_t event_type,
2236 struct task_struct *task);
2238 static void task_ctx_sched_out(struct perf_cpu_context *cpuctx,
2239 struct perf_event_context *ctx,
2240 enum event_type_t event_type)
2242 if (!cpuctx->task_ctx)
2245 if (WARN_ON_ONCE(ctx != cpuctx->task_ctx))
2248 ctx_sched_out(ctx, cpuctx, event_type);
2251 static void perf_event_sched_in(struct perf_cpu_context *cpuctx,
2252 struct perf_event_context *ctx,
2253 struct task_struct *task)
2255 cpu_ctx_sched_in(cpuctx, EVENT_PINNED, task);
2257 ctx_sched_in(ctx, cpuctx, EVENT_PINNED, task);
2258 cpu_ctx_sched_in(cpuctx, EVENT_FLEXIBLE, task);
2260 ctx_sched_in(ctx, cpuctx, EVENT_FLEXIBLE, task);
2264 * We want to maintain the following priority of scheduling:
2265 * - CPU pinned (EVENT_CPU | EVENT_PINNED)
2266 * - task pinned (EVENT_PINNED)
2267 * - CPU flexible (EVENT_CPU | EVENT_FLEXIBLE)
2268 * - task flexible (EVENT_FLEXIBLE).
2270 * In order to avoid unscheduling and scheduling back in everything every
2271 * time an event is added, only do it for the groups of equal priority and
2274 * This can be called after a batch operation on task events, in which case
2275 * event_type is a bit mask of the types of events involved. For CPU events,
2276 * event_type is only either EVENT_PINNED or EVENT_FLEXIBLE.
2278 static void ctx_resched(struct perf_cpu_context *cpuctx,
2279 struct perf_event_context *task_ctx,
2280 enum event_type_t event_type)
2282 enum event_type_t ctx_event_type = event_type & EVENT_ALL;
2283 bool cpu_event = !!(event_type & EVENT_CPU);
2286 * If pinned groups are involved, flexible groups also need to be
2289 if (event_type & EVENT_PINNED)
2290 event_type |= EVENT_FLEXIBLE;
2292 perf_pmu_disable(cpuctx->ctx.pmu);
2294 task_ctx_sched_out(cpuctx, task_ctx, event_type);
2297 * Decide which cpu ctx groups to schedule out based on the types
2298 * of events that caused rescheduling:
2299 * - EVENT_CPU: schedule out corresponding groups;
2300 * - EVENT_PINNED task events: schedule out EVENT_FLEXIBLE groups;
2301 * - otherwise, do nothing more.
2304 cpu_ctx_sched_out(cpuctx, ctx_event_type);
2305 else if (ctx_event_type & EVENT_PINNED)
2306 cpu_ctx_sched_out(cpuctx, EVENT_FLEXIBLE);
2308 perf_event_sched_in(cpuctx, task_ctx, current);
2309 perf_pmu_enable(cpuctx->ctx.pmu);
2313 * Cross CPU call to install and enable a performance event
2315 * Very similar to remote_function() + event_function() but cannot assume that
2316 * things like ctx->is_active and cpuctx->task_ctx are set.
2318 static int __perf_install_in_context(void *info)
2320 struct perf_event *event = info;
2321 struct perf_event_context *ctx = event->ctx;
2322 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
2323 struct perf_event_context *task_ctx = cpuctx->task_ctx;
2324 bool reprogram = true;
2327 raw_spin_lock(&cpuctx->ctx.lock);
2329 raw_spin_lock(&ctx->lock);
2332 reprogram = (ctx->task == current);
2335 * If the task is running, it must be running on this CPU,
2336 * otherwise we cannot reprogram things.
2338 * If its not running, we don't care, ctx->lock will
2339 * serialize against it becoming runnable.
2341 if (task_curr(ctx->task) && !reprogram) {
2346 WARN_ON_ONCE(reprogram && cpuctx->task_ctx && cpuctx->task_ctx != ctx);
2347 } else if (task_ctx) {
2348 raw_spin_lock(&task_ctx->lock);
2352 ctx_sched_out(ctx, cpuctx, EVENT_TIME);
2353 add_event_to_ctx(event, ctx);
2354 ctx_resched(cpuctx, task_ctx, get_event_type(event));
2356 add_event_to_ctx(event, ctx);
2360 perf_ctx_unlock(cpuctx, task_ctx);
2366 * Attach a performance event to a context.
2368 * Very similar to event_function_call, see comment there.
2371 perf_install_in_context(struct perf_event_context *ctx,
2372 struct perf_event *event,
2375 struct task_struct *task = READ_ONCE(ctx->task);
2377 lockdep_assert_held(&ctx->mutex);
2379 if (event->cpu != -1)
2383 * Ensures that if we can observe event->ctx, both the event and ctx
2384 * will be 'complete'. See perf_iterate_sb_cpu().
2386 smp_store_release(&event->ctx, ctx);
2389 cpu_function_call(cpu, __perf_install_in_context, event);
2394 * Should not happen, we validate the ctx is still alive before calling.
2396 if (WARN_ON_ONCE(task == TASK_TOMBSTONE))
2400 * Installing events is tricky because we cannot rely on ctx->is_active
2401 * to be set in case this is the nr_events 0 -> 1 transition.
2403 * Instead we use task_curr(), which tells us if the task is running.
2404 * However, since we use task_curr() outside of rq::lock, we can race
2405 * against the actual state. This means the result can be wrong.
2407 * If we get a false positive, we retry, this is harmless.
2409 * If we get a false negative, things are complicated. If we are after
2410 * perf_event_context_sched_in() ctx::lock will serialize us, and the
2411 * value must be correct. If we're before, it doesn't matter since
2412 * perf_event_context_sched_in() will program the counter.
2414 * However, this hinges on the remote context switch having observed
2415 * our task->perf_event_ctxp[] store, such that it will in fact take
2416 * ctx::lock in perf_event_context_sched_in().
2418 * We do this by task_function_call(), if the IPI fails to hit the task
2419 * we know any future context switch of task must see the
2420 * perf_event_ctpx[] store.
2424 * This smp_mb() orders the task->perf_event_ctxp[] store with the
2425 * task_cpu() load, such that if the IPI then does not find the task
2426 * running, a future context switch of that task must observe the
2431 if (!task_function_call(task, __perf_install_in_context, event))
2434 raw_spin_lock_irq(&ctx->lock);
2436 if (WARN_ON_ONCE(task == TASK_TOMBSTONE)) {
2438 * Cannot happen because we already checked above (which also
2439 * cannot happen), and we hold ctx->mutex, which serializes us
2440 * against perf_event_exit_task_context().
2442 raw_spin_unlock_irq(&ctx->lock);
2446 * If the task is not running, ctx->lock will avoid it becoming so,
2447 * thus we can safely install the event.
2449 if (task_curr(task)) {
2450 raw_spin_unlock_irq(&ctx->lock);
2453 add_event_to_ctx(event, ctx);
2454 raw_spin_unlock_irq(&ctx->lock);
2458 * Put a event into inactive state and update time fields.
2459 * Enabling the leader of a group effectively enables all
2460 * the group members that aren't explicitly disabled, so we
2461 * have to update their ->tstamp_enabled also.
2462 * Note: this works for group members as well as group leaders
2463 * since the non-leader members' sibling_lists will be empty.
2465 static void __perf_event_mark_enabled(struct perf_event *event)
2467 struct perf_event *sub;
2468 u64 tstamp = perf_event_time(event);
2470 event->state = PERF_EVENT_STATE_INACTIVE;
2471 event->tstamp_enabled = tstamp - event->total_time_enabled;
2472 list_for_each_entry(sub, &event->sibling_list, group_entry) {
2473 if (sub->state >= PERF_EVENT_STATE_INACTIVE)
2474 sub->tstamp_enabled = tstamp - sub->total_time_enabled;
2479 * Cross CPU call to enable a performance event
2481 static void __perf_event_enable(struct perf_event *event,
2482 struct perf_cpu_context *cpuctx,
2483 struct perf_event_context *ctx,
2486 struct perf_event *leader = event->group_leader;
2487 struct perf_event_context *task_ctx;
2489 if (event->state >= PERF_EVENT_STATE_INACTIVE ||
2490 event->state <= PERF_EVENT_STATE_ERROR)
2494 ctx_sched_out(ctx, cpuctx, EVENT_TIME);
2496 __perf_event_mark_enabled(event);
2498 if (!ctx->is_active)
2501 if (!event_filter_match(event)) {
2502 if (is_cgroup_event(event))
2503 perf_cgroup_defer_enabled(event);
2504 ctx_sched_in(ctx, cpuctx, EVENT_TIME, current);
2509 * If the event is in a group and isn't the group leader,
2510 * then don't put it on unless the group is on.
2512 if (leader != event && leader->state != PERF_EVENT_STATE_ACTIVE) {
2513 ctx_sched_in(ctx, cpuctx, EVENT_TIME, current);
2517 task_ctx = cpuctx->task_ctx;
2519 WARN_ON_ONCE(task_ctx != ctx);
2521 ctx_resched(cpuctx, task_ctx, get_event_type(event));
2527 * If event->ctx is a cloned context, callers must make sure that
2528 * every task struct that event->ctx->task could possibly point to
2529 * remains valid. This condition is satisfied when called through
2530 * perf_event_for_each_child or perf_event_for_each as described
2531 * for perf_event_disable.
2533 static void _perf_event_enable(struct perf_event *event)
2535 struct perf_event_context *ctx = event->ctx;
2537 raw_spin_lock_irq(&ctx->lock);
2538 if (event->state >= PERF_EVENT_STATE_INACTIVE ||
2539 event->state < PERF_EVENT_STATE_ERROR) {
2540 raw_spin_unlock_irq(&ctx->lock);
2545 * If the event is in error state, clear that first.
2547 * That way, if we see the event in error state below, we know that it
2548 * has gone back into error state, as distinct from the task having
2549 * been scheduled away before the cross-call arrived.
2551 if (event->state == PERF_EVENT_STATE_ERROR)
2552 event->state = PERF_EVENT_STATE_OFF;
2553 raw_spin_unlock_irq(&ctx->lock);
2555 event_function_call(event, __perf_event_enable, NULL);
2559 * See perf_event_disable();
2561 void perf_event_enable(struct perf_event *event)
2563 struct perf_event_context *ctx;
2565 ctx = perf_event_ctx_lock(event);
2566 _perf_event_enable(event);
2567 perf_event_ctx_unlock(event, ctx);
2569 EXPORT_SYMBOL_GPL(perf_event_enable);
2571 struct stop_event_data {
2572 struct perf_event *event;
2573 unsigned int restart;
2576 static int __perf_event_stop(void *info)
2578 struct stop_event_data *sd = info;
2579 struct perf_event *event = sd->event;
2581 /* if it's already INACTIVE, do nothing */
2582 if (READ_ONCE(event->state) != PERF_EVENT_STATE_ACTIVE)
2585 /* matches smp_wmb() in event_sched_in() */
2589 * There is a window with interrupts enabled before we get here,
2590 * so we need to check again lest we try to stop another CPU's event.
2592 if (READ_ONCE(event->oncpu) != smp_processor_id())
2595 event->pmu->stop(event, PERF_EF_UPDATE);
2598 * May race with the actual stop (through perf_pmu_output_stop()),
2599 * but it is only used for events with AUX ring buffer, and such
2600 * events will refuse to restart because of rb::aux_mmap_count==0,
2601 * see comments in perf_aux_output_begin().
2603 * Since this is happening on a event-local CPU, no trace is lost
2607 event->pmu->start(event, 0);
2612 static int perf_event_stop(struct perf_event *event, int restart)
2614 struct stop_event_data sd = {
2621 if (READ_ONCE(event->state) != PERF_EVENT_STATE_ACTIVE)
2624 /* matches smp_wmb() in event_sched_in() */
2628 * We only want to restart ACTIVE events, so if the event goes
2629 * inactive here (event->oncpu==-1), there's nothing more to do;
2630 * fall through with ret==-ENXIO.
2632 ret = cpu_function_call(READ_ONCE(event->oncpu),
2633 __perf_event_stop, &sd);
2634 } while (ret == -EAGAIN);
2640 * In order to contain the amount of racy and tricky in the address filter
2641 * configuration management, it is a two part process:
2643 * (p1) when userspace mappings change as a result of (1) or (2) or (3) below,
2644 * we update the addresses of corresponding vmas in
2645 * event::addr_filters_offs array and bump the event::addr_filters_gen;
2646 * (p2) when an event is scheduled in (pmu::add), it calls
2647 * perf_event_addr_filters_sync() which calls pmu::addr_filters_sync()
2648 * if the generation has changed since the previous call.
2650 * If (p1) happens while the event is active, we restart it to force (p2).
2652 * (1) perf_addr_filters_apply(): adjusting filters' offsets based on
2653 * pre-existing mappings, called once when new filters arrive via SET_FILTER
2655 * (2) perf_addr_filters_adjust(): adjusting filters' offsets based on newly
2656 * registered mapping, called for every new mmap(), with mm::mmap_sem down
2658 * (3) perf_event_addr_filters_exec(): clearing filters' offsets in the process
2661 void perf_event_addr_filters_sync(struct perf_event *event)
2663 struct perf_addr_filters_head *ifh = perf_event_addr_filters(event);
2665 if (!has_addr_filter(event))
2668 raw_spin_lock(&ifh->lock);
2669 if (event->addr_filters_gen != event->hw.addr_filters_gen) {
2670 event->pmu->addr_filters_sync(event);
2671 event->hw.addr_filters_gen = event->addr_filters_gen;
2673 raw_spin_unlock(&ifh->lock);
2675 EXPORT_SYMBOL_GPL(perf_event_addr_filters_sync);
2677 static int _perf_event_refresh(struct perf_event *event, int refresh)
2680 * not supported on inherited events
2682 if (event->attr.inherit || !is_sampling_event(event))
2685 atomic_add(refresh, &event->event_limit);
2686 _perf_event_enable(event);
2692 * See perf_event_disable()
2694 int perf_event_refresh(struct perf_event *event, int refresh)
2696 struct perf_event_context *ctx;
2699 ctx = perf_event_ctx_lock(event);
2700 ret = _perf_event_refresh(event, refresh);
2701 perf_event_ctx_unlock(event, ctx);
2705 EXPORT_SYMBOL_GPL(perf_event_refresh);
2707 static void ctx_sched_out(struct perf_event_context *ctx,
2708 struct perf_cpu_context *cpuctx,
2709 enum event_type_t event_type)
2711 int is_active = ctx->is_active;
2712 struct perf_event *event;
2714 lockdep_assert_held(&ctx->lock);
2716 if (likely(!ctx->nr_events)) {
2718 * See __perf_remove_from_context().
2720 WARN_ON_ONCE(ctx->is_active);
2722 WARN_ON_ONCE(cpuctx->task_ctx);
2726 ctx->is_active &= ~event_type;
2727 if (!(ctx->is_active & EVENT_ALL))
2731 WARN_ON_ONCE(cpuctx->task_ctx != ctx);
2732 if (!ctx->is_active)
2733 cpuctx->task_ctx = NULL;
2737 * Always update time if it was set; not only when it changes.
2738 * Otherwise we can 'forget' to update time for any but the last
2739 * context we sched out. For example:
2741 * ctx_sched_out(.event_type = EVENT_FLEXIBLE)
2742 * ctx_sched_out(.event_type = EVENT_PINNED)
2744 * would only update time for the pinned events.
2746 if (is_active & EVENT_TIME) {
2747 /* update (and stop) ctx time */
2748 update_context_time(ctx);
2749 update_cgrp_time_from_cpuctx(cpuctx);
2752 is_active ^= ctx->is_active; /* changed bits */
2754 if (!ctx->nr_active || !(is_active & EVENT_ALL))
2757 perf_pmu_disable(ctx->pmu);
2758 if (is_active & EVENT_PINNED) {
2759 list_for_each_entry(event, &ctx->pinned_groups, group_entry)
2760 group_sched_out(event, cpuctx, ctx);
2763 if (is_active & EVENT_FLEXIBLE) {
2764 list_for_each_entry(event, &ctx->flexible_groups, group_entry)
2765 group_sched_out(event, cpuctx, ctx);
2767 perf_pmu_enable(ctx->pmu);
2771 * Test whether two contexts are equivalent, i.e. whether they have both been
2772 * cloned from the same version of the same context.
2774 * Equivalence is measured using a generation number in the context that is
2775 * incremented on each modification to it; see unclone_ctx(), list_add_event()
2776 * and list_del_event().
2778 static int context_equiv(struct perf_event_context *ctx1,
2779 struct perf_event_context *ctx2)
2781 lockdep_assert_held(&ctx1->lock);
2782 lockdep_assert_held(&ctx2->lock);
2784 /* Pinning disables the swap optimization */
2785 if (ctx1->pin_count || ctx2->pin_count)
2788 /* If ctx1 is the parent of ctx2 */
2789 if (ctx1 == ctx2->parent_ctx && ctx1->generation == ctx2->parent_gen)
2792 /* If ctx2 is the parent of ctx1 */
2793 if (ctx1->parent_ctx == ctx2 && ctx1->parent_gen == ctx2->generation)
2797 * If ctx1 and ctx2 have the same parent; we flatten the parent
2798 * hierarchy, see perf_event_init_context().
2800 if (ctx1->parent_ctx && ctx1->parent_ctx == ctx2->parent_ctx &&
2801 ctx1->parent_gen == ctx2->parent_gen)
2808 static void __perf_event_sync_stat(struct perf_event *event,
2809 struct perf_event *next_event)
2813 if (!event->attr.inherit_stat)
2817 * Update the event value, we cannot use perf_event_read()
2818 * because we're in the middle of a context switch and have IRQs
2819 * disabled, which upsets smp_call_function_single(), however
2820 * we know the event must be on the current CPU, therefore we
2821 * don't need to use it.
2823 switch (event->state) {
2824 case PERF_EVENT_STATE_ACTIVE:
2825 event->pmu->read(event);
2828 case PERF_EVENT_STATE_INACTIVE:
2829 update_event_times(event);
2837 * In order to keep per-task stats reliable we need to flip the event
2838 * values when we flip the contexts.
2840 value = local64_read(&next_event->count);
2841 value = local64_xchg(&event->count, value);
2842 local64_set(&next_event->count, value);
2844 swap(event->total_time_enabled, next_event->total_time_enabled);
2845 swap(event->total_time_running, next_event->total_time_running);
2848 * Since we swizzled the values, update the user visible data too.
2850 perf_event_update_userpage(event);
2851 perf_event_update_userpage(next_event);
2854 static void perf_event_sync_stat(struct perf_event_context *ctx,
2855 struct perf_event_context *next_ctx)
2857 struct perf_event *event, *next_event;
2862 update_context_time(ctx);
2864 event = list_first_entry(&ctx->event_list,
2865 struct perf_event, event_entry);
2867 next_event = list_first_entry(&next_ctx->event_list,
2868 struct perf_event, event_entry);
2870 while (&event->event_entry != &ctx->event_list &&
2871 &next_event->event_entry != &next_ctx->event_list) {
2873 __perf_event_sync_stat(event, next_event);
2875 event = list_next_entry(event, event_entry);
2876 next_event = list_next_entry(next_event, event_entry);
2880 static void perf_event_context_sched_out(struct task_struct *task, int ctxn,
2881 struct task_struct *next)
2883 struct perf_event_context *ctx = task->perf_event_ctxp[ctxn];
2884 struct perf_event_context *next_ctx;
2885 struct perf_event_context *parent, *next_parent;
2886 struct perf_cpu_context *cpuctx;
2892 cpuctx = __get_cpu_context(ctx);
2893 if (!cpuctx->task_ctx)
2897 next_ctx = next->perf_event_ctxp[ctxn];
2901 parent = rcu_dereference(ctx->parent_ctx);
2902 next_parent = rcu_dereference(next_ctx->parent_ctx);
2904 /* If neither context have a parent context; they cannot be clones. */
2905 if (!parent && !next_parent)
2908 if (next_parent == ctx || next_ctx == parent || next_parent == parent) {
2910 * Looks like the two contexts are clones, so we might be
2911 * able to optimize the context switch. We lock both
2912 * contexts and check that they are clones under the
2913 * lock (including re-checking that neither has been
2914 * uncloned in the meantime). It doesn't matter which
2915 * order we take the locks because no other cpu could
2916 * be trying to lock both of these tasks.
2918 raw_spin_lock(&ctx->lock);
2919 raw_spin_lock_nested(&next_ctx->lock, SINGLE_DEPTH_NESTING);
2920 if (context_equiv(ctx, next_ctx)) {
2921 WRITE_ONCE(ctx->task, next);
2922 WRITE_ONCE(next_ctx->task, task);
2924 swap(ctx->task_ctx_data, next_ctx->task_ctx_data);
2927 * RCU_INIT_POINTER here is safe because we've not
2928 * modified the ctx and the above modification of
2929 * ctx->task and ctx->task_ctx_data are immaterial
2930 * since those values are always verified under
2931 * ctx->lock which we're now holding.
2933 RCU_INIT_POINTER(task->perf_event_ctxp[ctxn], next_ctx);
2934 RCU_INIT_POINTER(next->perf_event_ctxp[ctxn], ctx);
2938 perf_event_sync_stat(ctx, next_ctx);
2940 raw_spin_unlock(&next_ctx->lock);
2941 raw_spin_unlock(&ctx->lock);
2947 raw_spin_lock(&ctx->lock);
2948 task_ctx_sched_out(cpuctx, ctx, EVENT_ALL);
2949 raw_spin_unlock(&ctx->lock);
2953 static DEFINE_PER_CPU(struct list_head, sched_cb_list);
2955 void perf_sched_cb_dec(struct pmu *pmu)
2957 struct perf_cpu_context *cpuctx = this_cpu_ptr(pmu->pmu_cpu_context);
2959 this_cpu_dec(perf_sched_cb_usages);
2961 if (!--cpuctx->sched_cb_usage)
2962 list_del(&cpuctx->sched_cb_entry);
2966 void perf_sched_cb_inc(struct pmu *pmu)
2968 struct perf_cpu_context *cpuctx = this_cpu_ptr(pmu->pmu_cpu_context);
2970 if (!cpuctx->sched_cb_usage++)
2971 list_add(&cpuctx->sched_cb_entry, this_cpu_ptr(&sched_cb_list));
2973 this_cpu_inc(perf_sched_cb_usages);
2977 * This function provides the context switch callback to the lower code
2978 * layer. It is invoked ONLY when the context switch callback is enabled.
2980 * This callback is relevant even to per-cpu events; for example multi event
2981 * PEBS requires this to provide PID/TID information. This requires we flush
2982 * all queued PEBS records before we context switch to a new task.
2984 static void perf_pmu_sched_task(struct task_struct *prev,
2985 struct task_struct *next,
2988 struct perf_cpu_context *cpuctx;
2994 list_for_each_entry(cpuctx, this_cpu_ptr(&sched_cb_list), sched_cb_entry) {
2995 pmu = cpuctx->ctx.pmu; /* software PMUs will not have sched_task */
2997 if (WARN_ON_ONCE(!pmu->sched_task))
3000 perf_ctx_lock(cpuctx, cpuctx->task_ctx);
3001 perf_pmu_disable(pmu);
3003 pmu->sched_task(cpuctx->task_ctx, sched_in);
3005 perf_pmu_enable(pmu);
3006 perf_ctx_unlock(cpuctx, cpuctx->task_ctx);
3010 static void perf_event_switch(struct task_struct *task,
3011 struct task_struct *next_prev, bool sched_in);
3013 #define for_each_task_context_nr(ctxn) \
3014 for ((ctxn) = 0; (ctxn) < perf_nr_task_contexts; (ctxn)++)
3017 * Called from scheduler to remove the events of the current task,
3018 * with interrupts disabled.
3020 * We stop each event and update the event value in event->count.
3022 * This does not protect us against NMI, but disable()
3023 * sets the disabled bit in the control field of event _before_
3024 * accessing the event control register. If a NMI hits, then it will
3025 * not restart the event.
3027 void __perf_event_task_sched_out(struct task_struct *task,
3028 struct task_struct *next)
3032 if (__this_cpu_read(perf_sched_cb_usages))
3033 perf_pmu_sched_task(task, next, false);
3035 if (atomic_read(&nr_switch_events))
3036 perf_event_switch(task, next, false);
3038 for_each_task_context_nr(ctxn)
3039 perf_event_context_sched_out(task, ctxn, next);
3042 * if cgroup events exist on this CPU, then we need
3043 * to check if we have to switch out PMU state.
3044 * cgroup event are system-wide mode only
3046 if (atomic_read(this_cpu_ptr(&perf_cgroup_events)))
3047 perf_cgroup_sched_out(task, next);
3051 * Called with IRQs disabled
3053 static void cpu_ctx_sched_out(struct perf_cpu_context *cpuctx,
3054 enum event_type_t event_type)
3056 ctx_sched_out(&cpuctx->ctx, cpuctx, event_type);
3060 ctx_pinned_sched_in(struct perf_event_context *ctx,
3061 struct perf_cpu_context *cpuctx)
3063 struct perf_event *event;
3065 list_for_each_entry(event, &ctx->pinned_groups, group_entry) {
3066 if (event->state <= PERF_EVENT_STATE_OFF)
3068 if (!event_filter_match(event))
3071 /* may need to reset tstamp_enabled */
3072 if (is_cgroup_event(event))
3073 perf_cgroup_mark_enabled(event, ctx);
3075 if (group_can_go_on(event, cpuctx, 1))
3076 group_sched_in(event, cpuctx, ctx);
3079 * If this pinned group hasn't been scheduled,
3080 * put it in error state.
3082 if (event->state == PERF_EVENT_STATE_INACTIVE) {
3083 update_group_times(event);
3084 event->state = PERF_EVENT_STATE_ERROR;
3090 ctx_flexible_sched_in(struct perf_event_context *ctx,
3091 struct perf_cpu_context *cpuctx)
3093 struct perf_event *event;
3096 list_for_each_entry(event, &ctx->flexible_groups, group_entry) {
3097 /* Ignore events in OFF or ERROR state */
3098 if (event->state <= PERF_EVENT_STATE_OFF)
3101 * Listen to the 'cpu' scheduling filter constraint
3104 if (!event_filter_match(event))
3107 /* may need to reset tstamp_enabled */
3108 if (is_cgroup_event(event))
3109 perf_cgroup_mark_enabled(event, ctx);
3111 if (group_can_go_on(event, cpuctx, can_add_hw)) {
3112 if (group_sched_in(event, cpuctx, ctx))
3119 ctx_sched_in(struct perf_event_context *ctx,
3120 struct perf_cpu_context *cpuctx,
3121 enum event_type_t event_type,
3122 struct task_struct *task)
3124 int is_active = ctx->is_active;
3127 lockdep_assert_held(&ctx->lock);
3129 if (likely(!ctx->nr_events))
3132 ctx->is_active |= (event_type | EVENT_TIME);
3135 cpuctx->task_ctx = ctx;
3137 WARN_ON_ONCE(cpuctx->task_ctx != ctx);
3140 is_active ^= ctx->is_active; /* changed bits */
3142 if (is_active & EVENT_TIME) {
3143 /* start ctx time */
3145 ctx->timestamp = now;
3146 perf_cgroup_set_timestamp(task, ctx);
3150 * First go through the list and put on any pinned groups
3151 * in order to give them the best chance of going on.
3153 if (is_active & EVENT_PINNED)
3154 ctx_pinned_sched_in(ctx, cpuctx);
3156 /* Then walk through the lower prio flexible groups */
3157 if (is_active & EVENT_FLEXIBLE)
3158 ctx_flexible_sched_in(ctx, cpuctx);
3161 static void cpu_ctx_sched_in(struct perf_cpu_context *cpuctx,
3162 enum event_type_t event_type,
3163 struct task_struct *task)
3165 struct perf_event_context *ctx = &cpuctx->ctx;
3167 ctx_sched_in(ctx, cpuctx, event_type, task);
3170 static void perf_event_context_sched_in(struct perf_event_context *ctx,
3171 struct task_struct *task)
3173 struct perf_cpu_context *cpuctx;
3175 cpuctx = __get_cpu_context(ctx);
3176 if (cpuctx->task_ctx == ctx)
3179 perf_ctx_lock(cpuctx, ctx);
3180 perf_pmu_disable(ctx->pmu);
3182 * We want to keep the following priority order:
3183 * cpu pinned (that don't need to move), task pinned,
3184 * cpu flexible, task flexible.
3186 * However, if task's ctx is not carrying any pinned
3187 * events, no need to flip the cpuctx's events around.
3189 if (!list_empty(&ctx->pinned_groups))
3190 cpu_ctx_sched_out(cpuctx, EVENT_FLEXIBLE);
3191 perf_event_sched_in(cpuctx, ctx, task);
3192 perf_pmu_enable(ctx->pmu);
3193 perf_ctx_unlock(cpuctx, ctx);
3197 * Called from scheduler to add the events of the current task
3198 * with interrupts disabled.
3200 * We restore the event value and then enable it.
3202 * This does not protect us against NMI, but enable()
3203 * sets the enabled bit in the control field of event _before_
3204 * accessing the event control register. If a NMI hits, then it will
3205 * keep the event running.
3207 void __perf_event_task_sched_in(struct task_struct *prev,
3208 struct task_struct *task)
3210 struct perf_event_context *ctx;
3214 * If cgroup events exist on this CPU, then we need to check if we have
3215 * to switch in PMU state; cgroup event are system-wide mode only.
3217 * Since cgroup events are CPU events, we must schedule these in before
3218 * we schedule in the task events.
3220 if (atomic_read(this_cpu_ptr(&perf_cgroup_events)))
3221 perf_cgroup_sched_in(prev, task);
3223 for_each_task_context_nr(ctxn) {
3224 ctx = task->perf_event_ctxp[ctxn];
3228 perf_event_context_sched_in(ctx, task);
3231 if (atomic_read(&nr_switch_events))
3232 perf_event_switch(task, prev, true);
3234 if (__this_cpu_read(perf_sched_cb_usages))
3235 perf_pmu_sched_task(prev, task, true);
3238 static u64 perf_calculate_period(struct perf_event *event, u64 nsec, u64 count)
3240 u64 frequency = event->attr.sample_freq;
3241 u64 sec = NSEC_PER_SEC;
3242 u64 divisor, dividend;
3244 int count_fls, nsec_fls, frequency_fls, sec_fls;
3246 count_fls = fls64(count);
3247 nsec_fls = fls64(nsec);
3248 frequency_fls = fls64(frequency);
3252 * We got @count in @nsec, with a target of sample_freq HZ
3253 * the target period becomes:
3256 * period = -------------------
3257 * @nsec * sample_freq
3262 * Reduce accuracy by one bit such that @a and @b converge
3263 * to a similar magnitude.
3265 #define REDUCE_FLS(a, b) \
3267 if (a##_fls > b##_fls) { \
3277 * Reduce accuracy until either term fits in a u64, then proceed with
3278 * the other, so that finally we can do a u64/u64 division.
3280 while (count_fls + sec_fls > 64 && nsec_fls + frequency_fls > 64) {
3281 REDUCE_FLS(nsec, frequency);
3282 REDUCE_FLS(sec, count);
3285 if (count_fls + sec_fls > 64) {
3286 divisor = nsec * frequency;
3288 while (count_fls + sec_fls > 64) {
3289 REDUCE_FLS(count, sec);
3293 dividend = count * sec;
3295 dividend = count * sec;
3297 while (nsec_fls + frequency_fls > 64) {
3298 REDUCE_FLS(nsec, frequency);
3302 divisor = nsec * frequency;
3308 return div64_u64(dividend, divisor);
3311 static DEFINE_PER_CPU(int, perf_throttled_count);
3312 static DEFINE_PER_CPU(u64, perf_throttled_seq);
3314 static void perf_adjust_period(struct perf_event *event, u64 nsec, u64 count, bool disable)
3316 struct hw_perf_event *hwc = &event->hw;
3317 s64 period, sample_period;
3320 period = perf_calculate_period(event, nsec, count);
3322 delta = (s64)(period - hwc->sample_period);
3323 delta = (delta + 7) / 8; /* low pass filter */
3325 sample_period = hwc->sample_period + delta;
3330 hwc->sample_period = sample_period;
3332 if (local64_read(&hwc->period_left) > 8*sample_period) {
3334 event->pmu->stop(event, PERF_EF_UPDATE);
3336 local64_set(&hwc->period_left, 0);
3339 event->pmu->start(event, PERF_EF_RELOAD);
3344 * combine freq adjustment with unthrottling to avoid two passes over the
3345 * events. At the same time, make sure, having freq events does not change
3346 * the rate of unthrottling as that would introduce bias.
3348 static void perf_adjust_freq_unthr_context(struct perf_event_context *ctx,
3351 struct perf_event *event;
3352 struct hw_perf_event *hwc;
3353 u64 now, period = TICK_NSEC;
3357 * only need to iterate over all events iff:
3358 * - context have events in frequency mode (needs freq adjust)
3359 * - there are events to unthrottle on this cpu
3361 if (!(ctx->nr_freq || needs_unthr))
3364 raw_spin_lock(&ctx->lock);
3365 perf_pmu_disable(ctx->pmu);
3367 list_for_each_entry_rcu(event, &ctx->event_list, event_entry) {
3368 if (event->state != PERF_EVENT_STATE_ACTIVE)
3371 if (!event_filter_match(event))
3374 perf_pmu_disable(event->pmu);
3378 if (hwc->interrupts == MAX_INTERRUPTS) {
3379 hwc->interrupts = 0;
3380 perf_log_throttle(event, 1);
3381 event->pmu->start(event, 0);
3384 if (!event->attr.freq || !event->attr.sample_freq)
3388 * stop the event and update event->count
3390 event->pmu->stop(event, PERF_EF_UPDATE);
3392 now = local64_read(&event->count);
3393 delta = now - hwc->freq_count_stamp;
3394 hwc->freq_count_stamp = now;
3398 * reload only if value has changed
3399 * we have stopped the event so tell that
3400 * to perf_adjust_period() to avoid stopping it
3404 perf_adjust_period(event, period, delta, false);
3406 event->pmu->start(event, delta > 0 ? PERF_EF_RELOAD : 0);
3408 perf_pmu_enable(event->pmu);
3411 perf_pmu_enable(ctx->pmu);
3412 raw_spin_unlock(&ctx->lock);
3416 * Round-robin a context's events:
3418 static void rotate_ctx(struct perf_event_context *ctx)
3421 * Rotate the first entry last of non-pinned groups. Rotation might be
3422 * disabled by the inheritance code.
3424 if (!ctx->rotate_disable)
3425 list_rotate_left(&ctx->flexible_groups);
3428 static int perf_rotate_context(struct perf_cpu_context *cpuctx)
3430 struct perf_event_context *ctx = NULL;
3433 if (cpuctx->ctx.nr_events) {
3434 if (cpuctx->ctx.nr_events != cpuctx->ctx.nr_active)
3438 ctx = cpuctx->task_ctx;
3439 if (ctx && ctx->nr_events) {
3440 if (ctx->nr_events != ctx->nr_active)
3447 perf_ctx_lock(cpuctx, cpuctx->task_ctx);
3448 perf_pmu_disable(cpuctx->ctx.pmu);
3450 cpu_ctx_sched_out(cpuctx, EVENT_FLEXIBLE);
3452 ctx_sched_out(ctx, cpuctx, EVENT_FLEXIBLE);
3454 rotate_ctx(&cpuctx->ctx);
3458 perf_event_sched_in(cpuctx, ctx, current);
3460 perf_pmu_enable(cpuctx->ctx.pmu);
3461 perf_ctx_unlock(cpuctx, cpuctx->task_ctx);
3467 void perf_event_task_tick(void)
3469 struct list_head *head = this_cpu_ptr(&active_ctx_list);
3470 struct perf_event_context *ctx, *tmp;
3473 WARN_ON(!irqs_disabled());
3475 __this_cpu_inc(perf_throttled_seq);
3476 throttled = __this_cpu_xchg(perf_throttled_count, 0);
3477 tick_dep_clear_cpu(smp_processor_id(), TICK_DEP_BIT_PERF_EVENTS);
3479 list_for_each_entry_safe(ctx, tmp, head, active_ctx_list)
3480 perf_adjust_freq_unthr_context(ctx, throttled);
3483 static int event_enable_on_exec(struct perf_event *event,
3484 struct perf_event_context *ctx)
3486 if (!event->attr.enable_on_exec)
3489 event->attr.enable_on_exec = 0;
3490 if (event->state >= PERF_EVENT_STATE_INACTIVE)
3493 __perf_event_mark_enabled(event);
3499 * Enable all of a task's events that have been marked enable-on-exec.
3500 * This expects task == current.
3502 static void perf_event_enable_on_exec(int ctxn)
3504 struct perf_event_context *ctx, *clone_ctx = NULL;
3505 enum event_type_t event_type = 0;
3506 struct perf_cpu_context *cpuctx;
3507 struct perf_event *event;
3508 unsigned long flags;
3511 local_irq_save(flags);
3512 ctx = current->perf_event_ctxp[ctxn];
3513 if (!ctx || !ctx->nr_events)
3516 cpuctx = __get_cpu_context(ctx);
3517 perf_ctx_lock(cpuctx, ctx);
3518 ctx_sched_out(ctx, cpuctx, EVENT_TIME);
3519 list_for_each_entry(event, &ctx->event_list, event_entry) {
3520 enabled |= event_enable_on_exec(event, ctx);
3521 event_type |= get_event_type(event);
3525 * Unclone and reschedule this context if we enabled any event.
3528 clone_ctx = unclone_ctx(ctx);
3529 ctx_resched(cpuctx, ctx, event_type);
3531 ctx_sched_in(ctx, cpuctx, EVENT_TIME, current);
3533 perf_ctx_unlock(cpuctx, ctx);
3536 local_irq_restore(flags);
3542 struct perf_read_data {
3543 struct perf_event *event;
3548 static int __perf_event_read_cpu(struct perf_event *event, int event_cpu)
3550 u16 local_pkg, event_pkg;
3552 if (event->group_caps & PERF_EV_CAP_READ_ACTIVE_PKG) {
3553 int local_cpu = smp_processor_id();
3555 event_pkg = topology_physical_package_id(event_cpu);
3556 local_pkg = topology_physical_package_id(local_cpu);
3558 if (event_pkg == local_pkg)
3566 * Cross CPU call to read the hardware event
3568 static void __perf_event_read(void *info)
3570 struct perf_read_data *data = info;
3571 struct perf_event *sub, *event = data->event;
3572 struct perf_event_context *ctx = event->ctx;
3573 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
3574 struct pmu *pmu = event->pmu;
3577 * If this is a task context, we need to check whether it is
3578 * the current task context of this cpu. If not it has been
3579 * scheduled out before the smp call arrived. In that case
3580 * event->count would have been updated to a recent sample
3581 * when the event was scheduled out.
3583 if (ctx->task && cpuctx->task_ctx != ctx)
3586 raw_spin_lock(&ctx->lock);
3587 if (ctx->is_active) {
3588 update_context_time(ctx);
3589 update_cgrp_time_from_event(event);
3592 update_event_times(event);
3593 if (event->state != PERF_EVENT_STATE_ACTIVE)
3602 pmu->start_txn(pmu, PERF_PMU_TXN_READ);
3606 list_for_each_entry(sub, &event->sibling_list, group_entry) {
3607 update_event_times(sub);
3608 if (sub->state == PERF_EVENT_STATE_ACTIVE) {
3610 * Use sibling's PMU rather than @event's since
3611 * sibling could be on different (eg: software) PMU.
3613 sub->pmu->read(sub);
3617 data->ret = pmu->commit_txn(pmu);
3620 raw_spin_unlock(&ctx->lock);
3623 static inline u64 perf_event_count(struct perf_event *event)
3625 if (event->pmu->count)
3626 return event->pmu->count(event);
3628 return __perf_event_count(event);
3632 * NMI-safe method to read a local event, that is an event that
3634 * - either for the current task, or for this CPU
3635 * - does not have inherit set, for inherited task events
3636 * will not be local and we cannot read them atomically
3637 * - must not have a pmu::count method
3639 u64 perf_event_read_local(struct perf_event *event)
3641 unsigned long flags;
3645 * Disabling interrupts avoids all counter scheduling (context
3646 * switches, timer based rotation and IPIs).
3648 local_irq_save(flags);
3650 /* If this is a per-task event, it must be for current */
3651 WARN_ON_ONCE((event->attach_state & PERF_ATTACH_TASK) &&
3652 event->hw.target != current);
3654 /* If this is a per-CPU event, it must be for this CPU */
3655 WARN_ON_ONCE(!(event->attach_state & PERF_ATTACH_TASK) &&
3656 event->cpu != smp_processor_id());
3659 * It must not be an event with inherit set, we cannot read
3660 * all child counters from atomic context.
3662 WARN_ON_ONCE(event->attr.inherit);
3665 * It must not have a pmu::count method, those are not
3668 WARN_ON_ONCE(event->pmu->count);
3671 * If the event is currently on this CPU, its either a per-task event,
3672 * or local to this CPU. Furthermore it means its ACTIVE (otherwise
3675 if (event->oncpu == smp_processor_id())
3676 event->pmu->read(event);
3678 val = local64_read(&event->count);
3679 local_irq_restore(flags);
3684 static int perf_event_read(struct perf_event *event, bool group)
3686 int event_cpu, ret = 0;
3689 * If event is enabled and currently active on a CPU, update the
3690 * value in the event structure:
3692 if (event->state == PERF_EVENT_STATE_ACTIVE) {
3693 struct perf_read_data data = {
3699 event_cpu = READ_ONCE(event->oncpu);
3700 if ((unsigned)event_cpu >= nr_cpu_ids)
3704 event_cpu = __perf_event_read_cpu(event, event_cpu);
3707 * Purposely ignore the smp_call_function_single() return
3710 * If event_cpu isn't a valid CPU it means the event got
3711 * scheduled out and that will have updated the event count.
3713 * Therefore, either way, we'll have an up-to-date event count
3716 (void)smp_call_function_single(event_cpu, __perf_event_read, &data, 1);
3719 } else if (event->state == PERF_EVENT_STATE_INACTIVE) {
3720 struct perf_event_context *ctx = event->ctx;
3721 unsigned long flags;
3723 raw_spin_lock_irqsave(&ctx->lock, flags);
3725 * may read while context is not active
3726 * (e.g., thread is blocked), in that case
3727 * we cannot update context time
3729 if (ctx->is_active) {
3730 update_context_time(ctx);
3731 update_cgrp_time_from_event(event);
3734 update_group_times(event);
3736 update_event_times(event);
3737 raw_spin_unlock_irqrestore(&ctx->lock, flags);
3744 * Initialize the perf_event context in a task_struct:
3746 static void __perf_event_init_context(struct perf_event_context *ctx)
3748 raw_spin_lock_init(&ctx->lock);
3749 mutex_init(&ctx->mutex);
3750 INIT_LIST_HEAD(&ctx->active_ctx_list);
3751 INIT_LIST_HEAD(&ctx->pinned_groups);
3752 INIT_LIST_HEAD(&ctx->flexible_groups);
3753 INIT_LIST_HEAD(&ctx->event_list);
3754 atomic_set(&ctx->refcount, 1);
3757 static struct perf_event_context *
3758 alloc_perf_context(struct pmu *pmu, struct task_struct *task)
3760 struct perf_event_context *ctx;
3762 ctx = kzalloc(sizeof(struct perf_event_context), GFP_KERNEL);
3766 __perf_event_init_context(ctx);
3769 get_task_struct(task);
3776 static struct task_struct *
3777 find_lively_task_by_vpid(pid_t vpid)
3779 struct task_struct *task;
3785 task = find_task_by_vpid(vpid);
3787 get_task_struct(task);
3791 return ERR_PTR(-ESRCH);
3797 * Returns a matching context with refcount and pincount.
3799 static struct perf_event_context *
3800 find_get_context(struct pmu *pmu, struct task_struct *task,
3801 struct perf_event *event)
3803 struct perf_event_context *ctx, *clone_ctx = NULL;
3804 struct perf_cpu_context *cpuctx;
3805 void *task_ctx_data = NULL;
3806 unsigned long flags;
3808 int cpu = event->cpu;
3811 /* Must be root to operate on a CPU event: */
3812 if (perf_paranoid_cpu() && !capable(CAP_SYS_ADMIN))
3813 return ERR_PTR(-EACCES);
3816 * We could be clever and allow to attach a event to an
3817 * offline CPU and activate it when the CPU comes up, but
3820 if (!cpu_online(cpu))
3821 return ERR_PTR(-ENODEV);
3823 cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
3832 ctxn = pmu->task_ctx_nr;
3836 if (event->attach_state & PERF_ATTACH_TASK_DATA) {
3837 task_ctx_data = kzalloc(pmu->task_ctx_size, GFP_KERNEL);
3838 if (!task_ctx_data) {
3845 ctx = perf_lock_task_context(task, ctxn, &flags);
3847 clone_ctx = unclone_ctx(ctx);
3850 if (task_ctx_data && !ctx->task_ctx_data) {
3851 ctx->task_ctx_data = task_ctx_data;
3852 task_ctx_data = NULL;
3854 raw_spin_unlock_irqrestore(&ctx->lock, flags);
3859 ctx = alloc_perf_context(pmu, task);
3864 if (task_ctx_data) {
3865 ctx->task_ctx_data = task_ctx_data;
3866 task_ctx_data = NULL;
3870 mutex_lock(&task->perf_event_mutex);
3872 * If it has already passed perf_event_exit_task().
3873 * we must see PF_EXITING, it takes this mutex too.
3875 if (task->flags & PF_EXITING)
3877 else if (task->perf_event_ctxp[ctxn])
3882 rcu_assign_pointer(task->perf_event_ctxp[ctxn], ctx);
3884 mutex_unlock(&task->perf_event_mutex);
3886 if (unlikely(err)) {
3895 kfree(task_ctx_data);
3899 kfree(task_ctx_data);
3900 return ERR_PTR(err);
3903 static void perf_event_free_filter(struct perf_event *event);
3904 static void perf_event_free_bpf_prog(struct perf_event *event);
3906 static void free_event_rcu(struct rcu_head *head)
3908 struct perf_event *event;
3910 event = container_of(head, struct perf_event, rcu_head);
3912 put_pid_ns(event->ns);
3913 perf_event_free_filter(event);
3917 static void ring_buffer_attach(struct perf_event *event,
3918 struct ring_buffer *rb);
3920 static void detach_sb_event(struct perf_event *event)
3922 struct pmu_event_list *pel = per_cpu_ptr(&pmu_sb_events, event->cpu);
3924 raw_spin_lock(&pel->lock);
3925 list_del_rcu(&event->sb_list);
3926 raw_spin_unlock(&pel->lock);
3929 static bool is_sb_event(struct perf_event *event)
3931 struct perf_event_attr *attr = &event->attr;
3936 if (event->attach_state & PERF_ATTACH_TASK)
3939 if (attr->mmap || attr->mmap_data || attr->mmap2 ||
3940 attr->comm || attr->comm_exec ||
3942 attr->context_switch)
3947 static void unaccount_pmu_sb_event(struct perf_event *event)
3949 if (is_sb_event(event))
3950 detach_sb_event(event);
3953 static void unaccount_event_cpu(struct perf_event *event, int cpu)
3958 if (is_cgroup_event(event))
3959 atomic_dec(&per_cpu(perf_cgroup_events, cpu));
3962 #ifdef CONFIG_NO_HZ_FULL
3963 static DEFINE_SPINLOCK(nr_freq_lock);
3966 static void unaccount_freq_event_nohz(void)
3968 #ifdef CONFIG_NO_HZ_FULL
3969 spin_lock(&nr_freq_lock);
3970 if (atomic_dec_and_test(&nr_freq_events))
3971 tick_nohz_dep_clear(TICK_DEP_BIT_PERF_EVENTS);
3972 spin_unlock(&nr_freq_lock);
3976 static void unaccount_freq_event(void)
3978 if (tick_nohz_full_enabled())
3979 unaccount_freq_event_nohz();
3981 atomic_dec(&nr_freq_events);
3984 static void unaccount_event(struct perf_event *event)
3991 if (event->attach_state & PERF_ATTACH_TASK)
3993 if (event->attr.mmap || event->attr.mmap_data)
3994 atomic_dec(&nr_mmap_events);
3995 if (event->attr.comm)
3996 atomic_dec(&nr_comm_events);
3997 if (event->attr.namespaces)
3998 atomic_dec(&nr_namespaces_events);
3999 if (event->attr.task)
4000 atomic_dec(&nr_task_events);
4001 if (event->attr.freq)
4002 unaccount_freq_event();
4003 if (event->attr.context_switch) {
4005 atomic_dec(&nr_switch_events);
4007 if (is_cgroup_event(event))
4009 if (has_branch_stack(event))
4013 if (!atomic_add_unless(&perf_sched_count, -1, 1))
4014 schedule_delayed_work(&perf_sched_work, HZ);
4017 unaccount_event_cpu(event, event->cpu);
4019 unaccount_pmu_sb_event(event);
4022 static void perf_sched_delayed(struct work_struct *work)
4024 mutex_lock(&perf_sched_mutex);
4025 if (atomic_dec_and_test(&perf_sched_count))
4026 static_branch_disable(&perf_sched_events);
4027 mutex_unlock(&perf_sched_mutex);
4031 * The following implement mutual exclusion of events on "exclusive" pmus
4032 * (PERF_PMU_CAP_EXCLUSIVE). Such pmus can only have one event scheduled
4033 * at a time, so we disallow creating events that might conflict, namely:
4035 * 1) cpu-wide events in the presence of per-task events,
4036 * 2) per-task events in the presence of cpu-wide events,
4037 * 3) two matching events on the same context.
4039 * The former two cases are handled in the allocation path (perf_event_alloc(),
4040 * _free_event()), the latter -- before the first perf_install_in_context().
4042 static int exclusive_event_init(struct perf_event *event)
4044 struct pmu *pmu = event->pmu;
4046 if (!(pmu->capabilities & PERF_PMU_CAP_EXCLUSIVE))
4050 * Prevent co-existence of per-task and cpu-wide events on the
4051 * same exclusive pmu.
4053 * Negative pmu::exclusive_cnt means there are cpu-wide
4054 * events on this "exclusive" pmu, positive means there are
4057 * Since this is called in perf_event_alloc() path, event::ctx
4058 * doesn't exist yet; it is, however, safe to use PERF_ATTACH_TASK
4059 * to mean "per-task event", because unlike other attach states it
4060 * never gets cleared.
4062 if (event->attach_state & PERF_ATTACH_TASK) {
4063 if (!atomic_inc_unless_negative(&pmu->exclusive_cnt))
4066 if (!atomic_dec_unless_positive(&pmu->exclusive_cnt))
4073 static void exclusive_event_destroy(struct perf_event *event)
4075 struct pmu *pmu = event->pmu;
4077 if (!(pmu->capabilities & PERF_PMU_CAP_EXCLUSIVE))
4080 /* see comment in exclusive_event_init() */
4081 if (event->attach_state & PERF_ATTACH_TASK)
4082 atomic_dec(&pmu->exclusive_cnt);
4084 atomic_inc(&pmu->exclusive_cnt);
4087 static bool exclusive_event_match(struct perf_event *e1, struct perf_event *e2)
4089 if ((e1->pmu == e2->pmu) &&
4090 (e1->cpu == e2->cpu ||
4097 /* Called under the same ctx::mutex as perf_install_in_context() */
4098 static bool exclusive_event_installable(struct perf_event *event,
4099 struct perf_event_context *ctx)
4101 struct perf_event *iter_event;
4102 struct pmu *pmu = event->pmu;
4104 if (!(pmu->capabilities & PERF_PMU_CAP_EXCLUSIVE))
4107 list_for_each_entry(iter_event, &ctx->event_list, event_entry) {
4108 if (exclusive_event_match(iter_event, event))
4115 static void perf_addr_filters_splice(struct perf_event *event,
4116 struct list_head *head);
4118 static void _free_event(struct perf_event *event)
4120 irq_work_sync(&event->pending);
4122 unaccount_event(event);
4126 * Can happen when we close an event with re-directed output.
4128 * Since we have a 0 refcount, perf_mmap_close() will skip
4129 * over us; possibly making our ring_buffer_put() the last.
4131 mutex_lock(&event->mmap_mutex);
4132 ring_buffer_attach(event, NULL);
4133 mutex_unlock(&event->mmap_mutex);
4136 if (is_cgroup_event(event))
4137 perf_detach_cgroup(event);
4139 if (!event->parent) {
4140 if (event->attr.sample_type & PERF_SAMPLE_CALLCHAIN)
4141 put_callchain_buffers();
4144 perf_event_free_bpf_prog(event);
4145 perf_addr_filters_splice(event, NULL);
4146 kfree(event->addr_filters_offs);
4149 event->destroy(event);
4152 put_ctx(event->ctx);
4154 exclusive_event_destroy(event);
4155 module_put(event->pmu->module);
4157 call_rcu(&event->rcu_head, free_event_rcu);
4161 * Used to free events which have a known refcount of 1, such as in error paths
4162 * where the event isn't exposed yet and inherited events.
4164 static void free_event(struct perf_event *event)
4166 if (WARN(atomic_long_cmpxchg(&event->refcount, 1, 0) != 1,
4167 "unexpected event refcount: %ld; ptr=%p\n",
4168 atomic_long_read(&event->refcount), event)) {
4169 /* leak to avoid use-after-free */
4177 * Remove user event from the owner task.
4179 static void perf_remove_from_owner(struct perf_event *event)
4181 struct task_struct *owner;
4185 * Matches the smp_store_release() in perf_event_exit_task(). If we
4186 * observe !owner it means the list deletion is complete and we can
4187 * indeed free this event, otherwise we need to serialize on
4188 * owner->perf_event_mutex.
4190 owner = lockless_dereference(event->owner);
4193 * Since delayed_put_task_struct() also drops the last
4194 * task reference we can safely take a new reference
4195 * while holding the rcu_read_lock().
4197 get_task_struct(owner);
4203 * If we're here through perf_event_exit_task() we're already
4204 * holding ctx->mutex which would be an inversion wrt. the
4205 * normal lock order.
4207 * However we can safely take this lock because its the child
4210 mutex_lock_nested(&owner->perf_event_mutex, SINGLE_DEPTH_NESTING);
4213 * We have to re-check the event->owner field, if it is cleared
4214 * we raced with perf_event_exit_task(), acquiring the mutex
4215 * ensured they're done, and we can proceed with freeing the
4219 list_del_init(&event->owner_entry);
4220 smp_store_release(&event->owner, NULL);
4222 mutex_unlock(&owner->perf_event_mutex);
4223 put_task_struct(owner);
4227 static void put_event(struct perf_event *event)
4229 if (!atomic_long_dec_and_test(&event->refcount))
4236 * Kill an event dead; while event:refcount will preserve the event
4237 * object, it will not preserve its functionality. Once the last 'user'
4238 * gives up the object, we'll destroy the thing.
4240 int perf_event_release_kernel(struct perf_event *event)
4242 struct perf_event_context *ctx = event->ctx;
4243 struct perf_event *child, *tmp;
4246 * If we got here through err_file: fput(event_file); we will not have
4247 * attached to a context yet.
4250 WARN_ON_ONCE(event->attach_state &
4251 (PERF_ATTACH_CONTEXT|PERF_ATTACH_GROUP));
4255 if (!is_kernel_event(event))
4256 perf_remove_from_owner(event);
4258 ctx = perf_event_ctx_lock(event);
4259 WARN_ON_ONCE(ctx->parent_ctx);
4260 perf_remove_from_context(event, DETACH_GROUP);
4262 raw_spin_lock_irq(&ctx->lock);
4264 * Mark this event as STATE_DEAD, there is no external reference to it
4267 * Anybody acquiring event->child_mutex after the below loop _must_
4268 * also see this, most importantly inherit_event() which will avoid
4269 * placing more children on the list.
4271 * Thus this guarantees that we will in fact observe and kill _ALL_
4274 event->state = PERF_EVENT_STATE_DEAD;
4275 raw_spin_unlock_irq(&ctx->lock);
4277 perf_event_ctx_unlock(event, ctx);
4280 mutex_lock(&event->child_mutex);
4281 list_for_each_entry(child, &event->child_list, child_list) {
4284 * Cannot change, child events are not migrated, see the
4285 * comment with perf_event_ctx_lock_nested().
4287 ctx = lockless_dereference(child->ctx);
4289 * Since child_mutex nests inside ctx::mutex, we must jump
4290 * through hoops. We start by grabbing a reference on the ctx.
4292 * Since the event cannot get freed while we hold the
4293 * child_mutex, the context must also exist and have a !0
4299 * Now that we have a ctx ref, we can drop child_mutex, and
4300 * acquire ctx::mutex without fear of it going away. Then we
4301 * can re-acquire child_mutex.
4303 mutex_unlock(&event->child_mutex);
4304 mutex_lock(&ctx->mutex);
4305 mutex_lock(&event->child_mutex);
4308 * Now that we hold ctx::mutex and child_mutex, revalidate our
4309 * state, if child is still the first entry, it didn't get freed
4310 * and we can continue doing so.
4312 tmp = list_first_entry_or_null(&event->child_list,
4313 struct perf_event, child_list);
4315 perf_remove_from_context(child, DETACH_GROUP);
4316 list_del(&child->child_list);
4319 * This matches the refcount bump in inherit_event();
4320 * this can't be the last reference.
4325 mutex_unlock(&event->child_mutex);
4326 mutex_unlock(&ctx->mutex);
4330 mutex_unlock(&event->child_mutex);
4333 put_event(event); /* Must be the 'last' reference */
4336 EXPORT_SYMBOL_GPL(perf_event_release_kernel);
4339 * Called when the last reference to the file is gone.
4341 static int perf_release(struct inode *inode, struct file *file)
4343 perf_event_release_kernel(file->private_data);
4347 u64 perf_event_read_value(struct perf_event *event, u64 *enabled, u64 *running)
4349 struct perf_event *child;
4355 mutex_lock(&event->child_mutex);
4357 (void)perf_event_read(event, false);
4358 total += perf_event_count(event);
4360 *enabled += event->total_time_enabled +
4361 atomic64_read(&event->child_total_time_enabled);
4362 *running += event->total_time_running +
4363 atomic64_read(&event->child_total_time_running);
4365 list_for_each_entry(child, &event->child_list, child_list) {
4366 (void)perf_event_read(child, false);
4367 total += perf_event_count(child);
4368 *enabled += child->total_time_enabled;
4369 *running += child->total_time_running;
4371 mutex_unlock(&event->child_mutex);
4375 EXPORT_SYMBOL_GPL(perf_event_read_value);
4377 static int __perf_read_group_add(struct perf_event *leader,
4378 u64 read_format, u64 *values)
4380 struct perf_event *sub;
4381 int n = 1; /* skip @nr */
4384 ret = perf_event_read(leader, true);
4389 * Since we co-schedule groups, {enabled,running} times of siblings
4390 * will be identical to those of the leader, so we only publish one
4393 if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED) {
4394 values[n++] += leader->total_time_enabled +
4395 atomic64_read(&leader->child_total_time_enabled);
4398 if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING) {
4399 values[n++] += leader->total_time_running +
4400 atomic64_read(&leader->child_total_time_running);
4404 * Write {count,id} tuples for every sibling.
4406 values[n++] += perf_event_count(leader);
4407 if (read_format & PERF_FORMAT_ID)
4408 values[n++] = primary_event_id(leader);
4410 list_for_each_entry(sub, &leader->sibling_list, group_entry) {
4411 values[n++] += perf_event_count(sub);
4412 if (read_format & PERF_FORMAT_ID)
4413 values[n++] = primary_event_id(sub);
4419 static int perf_read_group(struct perf_event *event,
4420 u64 read_format, char __user *buf)
4422 struct perf_event *leader = event->group_leader, *child;
4423 struct perf_event_context *ctx = leader->ctx;
4427 lockdep_assert_held(&ctx->mutex);
4429 values = kzalloc(event->read_size, GFP_KERNEL);
4433 values[0] = 1 + leader->nr_siblings;
4436 * By locking the child_mutex of the leader we effectively
4437 * lock the child list of all siblings.. XXX explain how.
4439 mutex_lock(&leader->child_mutex);
4441 ret = __perf_read_group_add(leader, read_format, values);
4445 list_for_each_entry(child, &leader->child_list, child_list) {
4446 ret = __perf_read_group_add(child, read_format, values);
4451 mutex_unlock(&leader->child_mutex);
4453 ret = event->read_size;
4454 if (copy_to_user(buf, values, event->read_size))
4459 mutex_unlock(&leader->child_mutex);
4465 static int perf_read_one(struct perf_event *event,
4466 u64 read_format, char __user *buf)
4468 u64 enabled, running;
4472 values[n++] = perf_event_read_value(event, &enabled, &running);
4473 if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED)
4474 values[n++] = enabled;
4475 if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING)
4476 values[n++] = running;
4477 if (read_format & PERF_FORMAT_ID)
4478 values[n++] = primary_event_id(event);
4480 if (copy_to_user(buf, values, n * sizeof(u64)))
4483 return n * sizeof(u64);
4486 static bool is_event_hup(struct perf_event *event)
4490 if (event->state > PERF_EVENT_STATE_EXIT)
4493 mutex_lock(&event->child_mutex);
4494 no_children = list_empty(&event->child_list);
4495 mutex_unlock(&event->child_mutex);
4500 * Read the performance event - simple non blocking version for now
4503 __perf_read(struct perf_event *event, char __user *buf, size_t count)
4505 u64 read_format = event->attr.read_format;
4509 * Return end-of-file for a read on a event that is in
4510 * error state (i.e. because it was pinned but it couldn't be
4511 * scheduled on to the CPU at some point).
4513 if (event->state == PERF_EVENT_STATE_ERROR)
4516 if (count < event->read_size)
4519 WARN_ON_ONCE(event->ctx->parent_ctx);
4520 if (read_format & PERF_FORMAT_GROUP)
4521 ret = perf_read_group(event, read_format, buf);
4523 ret = perf_read_one(event, read_format, buf);
4529 perf_read(struct file *file, char __user *buf, size_t count, loff_t *ppos)
4531 struct perf_event *event = file->private_data;
4532 struct perf_event_context *ctx;
4535 ctx = perf_event_ctx_lock(event);
4536 ret = __perf_read(event, buf, count);
4537 perf_event_ctx_unlock(event, ctx);
4542 static unsigned int perf_poll(struct file *file, poll_table *wait)
4544 struct perf_event *event = file->private_data;
4545 struct ring_buffer *rb;
4546 unsigned int events = POLLHUP;
4548 poll_wait(file, &event->waitq, wait);
4550 if (is_event_hup(event))
4554 * Pin the event->rb by taking event->mmap_mutex; otherwise
4555 * perf_event_set_output() can swizzle our rb and make us miss wakeups.
4557 mutex_lock(&event->mmap_mutex);
4560 events = atomic_xchg(&rb->poll, 0);
4561 mutex_unlock(&event->mmap_mutex);
4565 static void _perf_event_reset(struct perf_event *event)
4567 (void)perf_event_read(event, false);
4568 local64_set(&event->count, 0);
4569 perf_event_update_userpage(event);
4573 * Holding the top-level event's child_mutex means that any
4574 * descendant process that has inherited this event will block
4575 * in perf_event_exit_event() if it goes to exit, thus satisfying the
4576 * task existence requirements of perf_event_enable/disable.
4578 static void perf_event_for_each_child(struct perf_event *event,
4579 void (*func)(struct perf_event *))
4581 struct perf_event *child;
4583 WARN_ON_ONCE(event->ctx->parent_ctx);
4585 mutex_lock(&event->child_mutex);
4587 list_for_each_entry(child, &event->child_list, child_list)
4589 mutex_unlock(&event->child_mutex);
4592 static void perf_event_for_each(struct perf_event *event,
4593 void (*func)(struct perf_event *))
4595 struct perf_event_context *ctx = event->ctx;
4596 struct perf_event *sibling;
4598 lockdep_assert_held(&ctx->mutex);
4600 event = event->group_leader;
4602 perf_event_for_each_child(event, func);
4603 list_for_each_entry(sibling, &event->sibling_list, group_entry)
4604 perf_event_for_each_child(sibling, func);
4607 static void __perf_event_period(struct perf_event *event,
4608 struct perf_cpu_context *cpuctx,
4609 struct perf_event_context *ctx,
4612 u64 value = *((u64 *)info);
4615 if (event->attr.freq) {
4616 event->attr.sample_freq = value;
4618 event->attr.sample_period = value;
4619 event->hw.sample_period = value;
4622 active = (event->state == PERF_EVENT_STATE_ACTIVE);
4624 perf_pmu_disable(ctx->pmu);
4626 * We could be throttled; unthrottle now to avoid the tick
4627 * trying to unthrottle while we already re-started the event.
4629 if (event->hw.interrupts == MAX_INTERRUPTS) {
4630 event->hw.interrupts = 0;
4631 perf_log_throttle(event, 1);
4633 event->pmu->stop(event, PERF_EF_UPDATE);
4636 local64_set(&event->hw.period_left, 0);
4639 event->pmu->start(event, PERF_EF_RELOAD);
4640 perf_pmu_enable(ctx->pmu);
4644 static int perf_event_period(struct perf_event *event, u64 __user *arg)
4648 if (!is_sampling_event(event))
4651 if (copy_from_user(&value, arg, sizeof(value)))
4657 if (event->attr.freq && value > sysctl_perf_event_sample_rate)
4660 event_function_call(event, __perf_event_period, &value);
4665 static const struct file_operations perf_fops;
4667 static inline int perf_fget_light(int fd, struct fd *p)
4669 struct fd f = fdget(fd);
4673 if (f.file->f_op != &perf_fops) {
4681 static int perf_event_set_output(struct perf_event *event,
4682 struct perf_event *output_event);
4683 static int perf_event_set_filter(struct perf_event *event, void __user *arg);
4684 static int perf_event_set_bpf_prog(struct perf_event *event, u32 prog_fd);
4686 static long _perf_ioctl(struct perf_event *event, unsigned int cmd, unsigned long arg)
4688 void (*func)(struct perf_event *);
4692 case PERF_EVENT_IOC_ENABLE:
4693 func = _perf_event_enable;
4695 case PERF_EVENT_IOC_DISABLE:
4696 func = _perf_event_disable;
4698 case PERF_EVENT_IOC_RESET:
4699 func = _perf_event_reset;
4702 case PERF_EVENT_IOC_REFRESH:
4703 return _perf_event_refresh(event, arg);
4705 case PERF_EVENT_IOC_PERIOD:
4706 return perf_event_period(event, (u64 __user *)arg);
4708 case PERF_EVENT_IOC_ID:
4710 u64 id = primary_event_id(event);
4712 if (copy_to_user((void __user *)arg, &id, sizeof(id)))
4717 case PERF_EVENT_IOC_SET_OUTPUT:
4721 struct perf_event *output_event;
4723 ret = perf_fget_light(arg, &output);
4726 output_event = output.file->private_data;
4727 ret = perf_event_set_output(event, output_event);
4730 ret = perf_event_set_output(event, NULL);
4735 case PERF_EVENT_IOC_SET_FILTER:
4736 return perf_event_set_filter(event, (void __user *)arg);
4738 case PERF_EVENT_IOC_SET_BPF:
4739 return perf_event_set_bpf_prog(event, arg);
4741 case PERF_EVENT_IOC_PAUSE_OUTPUT: {
4742 struct ring_buffer *rb;
4745 rb = rcu_dereference(event->rb);
4746 if (!rb || !rb->nr_pages) {
4750 rb_toggle_paused(rb, !!arg);
4758 if (flags & PERF_IOC_FLAG_GROUP)
4759 perf_event_for_each(event, func);
4761 perf_event_for_each_child(event, func);
4766 static long perf_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
4768 struct perf_event *event = file->private_data;
4769 struct perf_event_context *ctx;
4772 ctx = perf_event_ctx_lock(event);
4773 ret = _perf_ioctl(event, cmd, arg);
4774 perf_event_ctx_unlock(event, ctx);
4779 #ifdef CONFIG_COMPAT
4780 static long perf_compat_ioctl(struct file *file, unsigned int cmd,
4783 switch (_IOC_NR(cmd)) {
4784 case _IOC_NR(PERF_EVENT_IOC_SET_FILTER):
4785 case _IOC_NR(PERF_EVENT_IOC_ID):
4786 /* Fix up pointer size (usually 4 -> 8 in 32-on-64-bit case */
4787 if (_IOC_SIZE(cmd) == sizeof(compat_uptr_t)) {
4788 cmd &= ~IOCSIZE_MASK;
4789 cmd |= sizeof(void *) << IOCSIZE_SHIFT;
4793 return perf_ioctl(file, cmd, arg);
4796 # define perf_compat_ioctl NULL
4799 int perf_event_task_enable(void)
4801 struct perf_event_context *ctx;
4802 struct perf_event *event;
4804 mutex_lock(¤t->perf_event_mutex);
4805 list_for_each_entry(event, ¤t->perf_event_list, owner_entry) {
4806 ctx = perf_event_ctx_lock(event);
4807 perf_event_for_each_child(event, _perf_event_enable);
4808 perf_event_ctx_unlock(event, ctx);
4810 mutex_unlock(¤t->perf_event_mutex);
4815 int perf_event_task_disable(void)
4817 struct perf_event_context *ctx;
4818 struct perf_event *event;
4820 mutex_lock(¤t->perf_event_mutex);
4821 list_for_each_entry(event, ¤t->perf_event_list, owner_entry) {
4822 ctx = perf_event_ctx_lock(event);
4823 perf_event_for_each_child(event, _perf_event_disable);
4824 perf_event_ctx_unlock(event, ctx);
4826 mutex_unlock(¤t->perf_event_mutex);
4831 static int perf_event_index(struct perf_event *event)
4833 if (event->hw.state & PERF_HES_STOPPED)
4836 if (event->state != PERF_EVENT_STATE_ACTIVE)
4839 return event->pmu->event_idx(event);
4842 static void calc_timer_values(struct perf_event *event,
4849 *now = perf_clock();
4850 ctx_time = event->shadow_ctx_time + *now;
4851 *enabled = ctx_time - event->tstamp_enabled;
4852 *running = ctx_time - event->tstamp_running;
4855 static void perf_event_init_userpage(struct perf_event *event)
4857 struct perf_event_mmap_page *userpg;
4858 struct ring_buffer *rb;
4861 rb = rcu_dereference(event->rb);
4865 userpg = rb->user_page;
4867 /* Allow new userspace to detect that bit 0 is deprecated */
4868 userpg->cap_bit0_is_deprecated = 1;
4869 userpg->size = offsetof(struct perf_event_mmap_page, __reserved);
4870 userpg->data_offset = PAGE_SIZE;
4871 userpg->data_size = perf_data_size(rb);
4877 void __weak arch_perf_update_userpage(
4878 struct perf_event *event, struct perf_event_mmap_page *userpg, u64 now)
4883 * Callers need to ensure there can be no nesting of this function, otherwise
4884 * the seqlock logic goes bad. We can not serialize this because the arch
4885 * code calls this from NMI context.
4887 void perf_event_update_userpage(struct perf_event *event)
4889 struct perf_event_mmap_page *userpg;
4890 struct ring_buffer *rb;
4891 u64 enabled, running, now;
4894 rb = rcu_dereference(event->rb);
4899 * compute total_time_enabled, total_time_running
4900 * based on snapshot values taken when the event
4901 * was last scheduled in.
4903 * we cannot simply called update_context_time()
4904 * because of locking issue as we can be called in
4907 calc_timer_values(event, &now, &enabled, &running);
4909 userpg = rb->user_page;
4911 * Disable preemption so as to not let the corresponding user-space
4912 * spin too long if we get preempted.
4917 userpg->index = perf_event_index(event);
4918 userpg->offset = perf_event_count(event);
4920 userpg->offset -= local64_read(&event->hw.prev_count);
4922 userpg->time_enabled = enabled +
4923 atomic64_read(&event->child_total_time_enabled);
4925 userpg->time_running = running +
4926 atomic64_read(&event->child_total_time_running);
4928 arch_perf_update_userpage(event, userpg, now);
4937 static int perf_mmap_fault(struct vm_fault *vmf)
4939 struct perf_event *event = vmf->vma->vm_file->private_data;
4940 struct ring_buffer *rb;
4941 int ret = VM_FAULT_SIGBUS;
4943 if (vmf->flags & FAULT_FLAG_MKWRITE) {
4944 if (vmf->pgoff == 0)
4950 rb = rcu_dereference(event->rb);
4954 if (vmf->pgoff && (vmf->flags & FAULT_FLAG_WRITE))
4957 vmf->page = perf_mmap_to_page(rb, vmf->pgoff);
4961 get_page(vmf->page);
4962 vmf->page->mapping = vmf->vma->vm_file->f_mapping;
4963 vmf->page->index = vmf->pgoff;
4972 static void ring_buffer_attach(struct perf_event *event,
4973 struct ring_buffer *rb)
4975 struct ring_buffer *old_rb = NULL;
4976 unsigned long flags;
4980 * Should be impossible, we set this when removing
4981 * event->rb_entry and wait/clear when adding event->rb_entry.
4983 WARN_ON_ONCE(event->rcu_pending);
4986 spin_lock_irqsave(&old_rb->event_lock, flags);
4987 list_del_rcu(&event->rb_entry);
4988 spin_unlock_irqrestore(&old_rb->event_lock, flags);
4990 event->rcu_batches = get_state_synchronize_rcu();
4991 event->rcu_pending = 1;
4995 if (event->rcu_pending) {
4996 cond_synchronize_rcu(event->rcu_batches);
4997 event->rcu_pending = 0;
5000 spin_lock_irqsave(&rb->event_lock, flags);
5001 list_add_rcu(&event->rb_entry, &rb->event_list);
5002 spin_unlock_irqrestore(&rb->event_lock, flags);
5006 * Avoid racing with perf_mmap_close(AUX): stop the event
5007 * before swizzling the event::rb pointer; if it's getting
5008 * unmapped, its aux_mmap_count will be 0 and it won't
5009 * restart. See the comment in __perf_pmu_output_stop().
5011 * Data will inevitably be lost when set_output is done in
5012 * mid-air, but then again, whoever does it like this is
5013 * not in for the data anyway.
5016 perf_event_stop(event, 0);
5018 rcu_assign_pointer(event->rb, rb);
5021 ring_buffer_put(old_rb);
5023 * Since we detached before setting the new rb, so that we
5024 * could attach the new rb, we could have missed a wakeup.
5027 wake_up_all(&event->waitq);
5031 static void ring_buffer_wakeup(struct perf_event *event)
5033 struct ring_buffer *rb;
5036 rb = rcu_dereference(event->rb);
5038 list_for_each_entry_rcu(event, &rb->event_list, rb_entry)
5039 wake_up_all(&event->waitq);
5044 struct ring_buffer *ring_buffer_get(struct perf_event *event)
5046 struct ring_buffer *rb;
5049 rb = rcu_dereference(event->rb);
5051 if (!atomic_inc_not_zero(&rb->refcount))
5059 void ring_buffer_put(struct ring_buffer *rb)
5061 if (!atomic_dec_and_test(&rb->refcount))
5064 WARN_ON_ONCE(!list_empty(&rb->event_list));
5066 call_rcu(&rb->rcu_head, rb_free_rcu);
5069 static void perf_mmap_open(struct vm_area_struct *vma)
5071 struct perf_event *event = vma->vm_file->private_data;
5073 atomic_inc(&event->mmap_count);
5074 atomic_inc(&event->rb->mmap_count);
5077 atomic_inc(&event->rb->aux_mmap_count);
5079 if (event->pmu->event_mapped)
5080 event->pmu->event_mapped(event);
5083 static void perf_pmu_output_stop(struct perf_event *event);
5086 * A buffer can be mmap()ed multiple times; either directly through the same
5087 * event, or through other events by use of perf_event_set_output().
5089 * In order to undo the VM accounting done by perf_mmap() we need to destroy
5090 * the buffer here, where we still have a VM context. This means we need
5091 * to detach all events redirecting to us.
5093 static void perf_mmap_close(struct vm_area_struct *vma)
5095 struct perf_event *event = vma->vm_file->private_data;
5097 struct ring_buffer *rb = ring_buffer_get(event);
5098 struct user_struct *mmap_user = rb->mmap_user;
5099 int mmap_locked = rb->mmap_locked;
5100 unsigned long size = perf_data_size(rb);
5102 if (event->pmu->event_unmapped)
5103 event->pmu->event_unmapped(event);
5106 * rb->aux_mmap_count will always drop before rb->mmap_count and
5107 * event->mmap_count, so it is ok to use event->mmap_mutex to
5108 * serialize with perf_mmap here.
5110 if (rb_has_aux(rb) && vma->vm_pgoff == rb->aux_pgoff &&
5111 atomic_dec_and_mutex_lock(&rb->aux_mmap_count, &event->mmap_mutex)) {
5113 * Stop all AUX events that are writing to this buffer,
5114 * so that we can free its AUX pages and corresponding PMU
5115 * data. Note that after rb::aux_mmap_count dropped to zero,
5116 * they won't start any more (see perf_aux_output_begin()).
5118 perf_pmu_output_stop(event);
5120 /* now it's safe to free the pages */
5121 atomic_long_sub(rb->aux_nr_pages, &mmap_user->locked_vm);
5122 vma->vm_mm->pinned_vm -= rb->aux_mmap_locked;
5124 /* this has to be the last one */
5126 WARN_ON_ONCE(atomic_read(&rb->aux_refcount));
5128 mutex_unlock(&event->mmap_mutex);
5131 atomic_dec(&rb->mmap_count);
5133 if (!atomic_dec_and_mutex_lock(&event->mmap_count, &event->mmap_mutex))
5136 ring_buffer_attach(event, NULL);
5137 mutex_unlock(&event->mmap_mutex);
5139 /* If there's still other mmap()s of this buffer, we're done. */
5140 if (atomic_read(&rb->mmap_count))
5144 * No other mmap()s, detach from all other events that might redirect
5145 * into the now unreachable buffer. Somewhat complicated by the
5146 * fact that rb::event_lock otherwise nests inside mmap_mutex.
5150 list_for_each_entry_rcu(event, &rb->event_list, rb_entry) {
5151 if (!atomic_long_inc_not_zero(&event->refcount)) {
5153 * This event is en-route to free_event() which will
5154 * detach it and remove it from the list.
5160 mutex_lock(&event->mmap_mutex);
5162 * Check we didn't race with perf_event_set_output() which can
5163 * swizzle the rb from under us while we were waiting to
5164 * acquire mmap_mutex.
5166 * If we find a different rb; ignore this event, a next
5167 * iteration will no longer find it on the list. We have to
5168 * still restart the iteration to make sure we're not now
5169 * iterating the wrong list.
5171 if (event->rb == rb)
5172 ring_buffer_attach(event, NULL);
5174 mutex_unlock(&event->mmap_mutex);
5178 * Restart the iteration; either we're on the wrong list or
5179 * destroyed its integrity by doing a deletion.
5186 * It could be there's still a few 0-ref events on the list; they'll
5187 * get cleaned up by free_event() -- they'll also still have their
5188 * ref on the rb and will free it whenever they are done with it.
5190 * Aside from that, this buffer is 'fully' detached and unmapped,
5191 * undo the VM accounting.
5194 atomic_long_sub((size >> PAGE_SHIFT) + 1, &mmap_user->locked_vm);
5195 vma->vm_mm->pinned_vm -= mmap_locked;
5196 free_uid(mmap_user);
5199 ring_buffer_put(rb); /* could be last */
5202 static const struct vm_operations_struct perf_mmap_vmops = {
5203 .open = perf_mmap_open,
5204 .close = perf_mmap_close, /* non mergable */
5205 .fault = perf_mmap_fault,
5206 .page_mkwrite = perf_mmap_fault,
5209 static int perf_mmap(struct file *file, struct vm_area_struct *vma)
5211 struct perf_event *event = file->private_data;
5212 unsigned long user_locked, user_lock_limit;
5213 struct user_struct *user = current_user();
5214 unsigned long locked, lock_limit;
5215 struct ring_buffer *rb = NULL;
5216 unsigned long vma_size;
5217 unsigned long nr_pages;
5218 long user_extra = 0, extra = 0;
5219 int ret = 0, flags = 0;
5222 * Don't allow mmap() of inherited per-task counters. This would
5223 * create a performance issue due to all children writing to the
5226 if (event->cpu == -1 && event->attr.inherit)
5229 if (!(vma->vm_flags & VM_SHARED))
5232 vma_size = vma->vm_end - vma->vm_start;
5234 if (vma->vm_pgoff == 0) {
5235 nr_pages = (vma_size / PAGE_SIZE) - 1;
5238 * AUX area mapping: if rb->aux_nr_pages != 0, it's already
5239 * mapped, all subsequent mappings should have the same size
5240 * and offset. Must be above the normal perf buffer.
5242 u64 aux_offset, aux_size;
5247 nr_pages = vma_size / PAGE_SIZE;
5249 mutex_lock(&event->mmap_mutex);
5256 aux_offset = ACCESS_ONCE(rb->user_page->aux_offset);
5257 aux_size = ACCESS_ONCE(rb->user_page->aux_size);
5259 if (aux_offset < perf_data_size(rb) + PAGE_SIZE)
5262 if (aux_offset != vma->vm_pgoff << PAGE_SHIFT)
5265 /* already mapped with a different offset */
5266 if (rb_has_aux(rb) && rb->aux_pgoff != vma->vm_pgoff)
5269 if (aux_size != vma_size || aux_size != nr_pages * PAGE_SIZE)
5272 /* already mapped with a different size */
5273 if (rb_has_aux(rb) && rb->aux_nr_pages != nr_pages)
5276 if (!is_power_of_2(nr_pages))
5279 if (!atomic_inc_not_zero(&rb->mmap_count))
5282 if (rb_has_aux(rb)) {
5283 atomic_inc(&rb->aux_mmap_count);
5288 atomic_set(&rb->aux_mmap_count, 1);
5289 user_extra = nr_pages;
5295 * If we have rb pages ensure they're a power-of-two number, so we
5296 * can do bitmasks instead of modulo.
5298 if (nr_pages != 0 && !is_power_of_2(nr_pages))
5301 if (vma_size != PAGE_SIZE * (1 + nr_pages))
5304 WARN_ON_ONCE(event->ctx->parent_ctx);
5306 mutex_lock(&event->mmap_mutex);
5308 if (event->rb->nr_pages != nr_pages) {
5313 if (!atomic_inc_not_zero(&event->rb->mmap_count)) {
5315 * Raced against perf_mmap_close() through
5316 * perf_event_set_output(). Try again, hope for better
5319 mutex_unlock(&event->mmap_mutex);
5326 user_extra = nr_pages + 1;
5329 user_lock_limit = sysctl_perf_event_mlock >> (PAGE_SHIFT - 10);
5332 * Increase the limit linearly with more CPUs:
5334 user_lock_limit *= num_online_cpus();
5336 user_locked = atomic_long_read(&user->locked_vm) + user_extra;
5338 if (user_locked > user_lock_limit)
5339 extra = user_locked - user_lock_limit;
5341 lock_limit = rlimit(RLIMIT_MEMLOCK);
5342 lock_limit >>= PAGE_SHIFT;
5343 locked = vma->vm_mm->pinned_vm + extra;
5345 if ((locked > lock_limit) && perf_paranoid_tracepoint_raw() &&
5346 !capable(CAP_IPC_LOCK)) {
5351 WARN_ON(!rb && event->rb);
5353 if (vma->vm_flags & VM_WRITE)
5354 flags |= RING_BUFFER_WRITABLE;
5357 rb = rb_alloc(nr_pages,
5358 event->attr.watermark ? event->attr.wakeup_watermark : 0,
5366 atomic_set(&rb->mmap_count, 1);
5367 rb->mmap_user = get_current_user();
5368 rb->mmap_locked = extra;
5370 ring_buffer_attach(event, rb);
5372 perf_event_init_userpage(event);
5373 perf_event_update_userpage(event);
5375 ret = rb_alloc_aux(rb, event, vma->vm_pgoff, nr_pages,
5376 event->attr.aux_watermark, flags);
5378 rb->aux_mmap_locked = extra;
5383 atomic_long_add(user_extra, &user->locked_vm);
5384 vma->vm_mm->pinned_vm += extra;
5386 atomic_inc(&event->mmap_count);
5388 atomic_dec(&rb->mmap_count);
5391 mutex_unlock(&event->mmap_mutex);
5394 * Since pinned accounting is per vm we cannot allow fork() to copy our
5397 vma->vm_flags |= VM_DONTCOPY | VM_DONTEXPAND | VM_DONTDUMP;
5398 vma->vm_ops = &perf_mmap_vmops;
5400 if (event->pmu->event_mapped)
5401 event->pmu->event_mapped(event);
5406 static int perf_fasync(int fd, struct file *filp, int on)
5408 struct inode *inode = file_inode(filp);
5409 struct perf_event *event = filp->private_data;
5413 retval = fasync_helper(fd, filp, on, &event->fasync);
5414 inode_unlock(inode);
5422 static const struct file_operations perf_fops = {
5423 .llseek = no_llseek,
5424 .release = perf_release,
5427 .unlocked_ioctl = perf_ioctl,
5428 .compat_ioctl = perf_compat_ioctl,
5430 .fasync = perf_fasync,
5436 * If there's data, ensure we set the poll() state and publish everything
5437 * to user-space before waking everybody up.
5440 static inline struct fasync_struct **perf_event_fasync(struct perf_event *event)
5442 /* only the parent has fasync state */
5444 event = event->parent;
5445 return &event->fasync;
5448 void perf_event_wakeup(struct perf_event *event)
5450 ring_buffer_wakeup(event);
5452 if (event->pending_kill) {
5453 kill_fasync(perf_event_fasync(event), SIGIO, event->pending_kill);
5454 event->pending_kill = 0;
5458 static void perf_pending_event(struct irq_work *entry)
5460 struct perf_event *event = container_of(entry,
5461 struct perf_event, pending);
5464 rctx = perf_swevent_get_recursion_context();
5466 * If we 'fail' here, that's OK, it means recursion is already disabled
5467 * and we won't recurse 'further'.
5470 if (event->pending_disable) {
5471 event->pending_disable = 0;
5472 perf_event_disable_local(event);
5475 if (event->pending_wakeup) {
5476 event->pending_wakeup = 0;
5477 perf_event_wakeup(event);
5481 perf_swevent_put_recursion_context(rctx);
5485 * We assume there is only KVM supporting the callbacks.
5486 * Later on, we might change it to a list if there is
5487 * another virtualization implementation supporting the callbacks.
5489 struct perf_guest_info_callbacks *perf_guest_cbs;
5491 int perf_register_guest_info_callbacks(struct perf_guest_info_callbacks *cbs)
5493 perf_guest_cbs = cbs;
5496 EXPORT_SYMBOL_GPL(perf_register_guest_info_callbacks);
5498 int perf_unregister_guest_info_callbacks(struct perf_guest_info_callbacks *cbs)
5500 perf_guest_cbs = NULL;
5503 EXPORT_SYMBOL_GPL(perf_unregister_guest_info_callbacks);
5506 perf_output_sample_regs(struct perf_output_handle *handle,
5507 struct pt_regs *regs, u64 mask)
5510 DECLARE_BITMAP(_mask, 64);
5512 bitmap_from_u64(_mask, mask);
5513 for_each_set_bit(bit, _mask, sizeof(mask) * BITS_PER_BYTE) {
5516 val = perf_reg_value(regs, bit);
5517 perf_output_put(handle, val);
5521 static void perf_sample_regs_user(struct perf_regs *regs_user,
5522 struct pt_regs *regs,
5523 struct pt_regs *regs_user_copy)
5525 if (user_mode(regs)) {
5526 regs_user->abi = perf_reg_abi(current);
5527 regs_user->regs = regs;
5528 } else if (current->mm) {
5529 perf_get_regs_user(regs_user, regs, regs_user_copy);
5531 regs_user->abi = PERF_SAMPLE_REGS_ABI_NONE;
5532 regs_user->regs = NULL;
5536 static void perf_sample_regs_intr(struct perf_regs *regs_intr,
5537 struct pt_regs *regs)
5539 regs_intr->regs = regs;
5540 regs_intr->abi = perf_reg_abi(current);
5545 * Get remaining task size from user stack pointer.
5547 * It'd be better to take stack vma map and limit this more
5548 * precisly, but there's no way to get it safely under interrupt,
5549 * so using TASK_SIZE as limit.
5551 static u64 perf_ustack_task_size(struct pt_regs *regs)
5553 unsigned long addr = perf_user_stack_pointer(regs);
5555 if (!addr || addr >= TASK_SIZE)
5558 return TASK_SIZE - addr;
5562 perf_sample_ustack_size(u16 stack_size, u16 header_size,
5563 struct pt_regs *regs)
5567 /* No regs, no stack pointer, no dump. */
5572 * Check if we fit in with the requested stack size into the:
5574 * If we don't, we limit the size to the TASK_SIZE.
5576 * - remaining sample size
5577 * If we don't, we customize the stack size to
5578 * fit in to the remaining sample size.
5581 task_size = min((u64) USHRT_MAX, perf_ustack_task_size(regs));
5582 stack_size = min(stack_size, (u16) task_size);
5584 /* Current header size plus static size and dynamic size. */
5585 header_size += 2 * sizeof(u64);
5587 /* Do we fit in with the current stack dump size? */
5588 if ((u16) (header_size + stack_size) < header_size) {
5590 * If we overflow the maximum size for the sample,
5591 * we customize the stack dump size to fit in.
5593 stack_size = USHRT_MAX - header_size - sizeof(u64);
5594 stack_size = round_up(stack_size, sizeof(u64));
5601 perf_output_sample_ustack(struct perf_output_handle *handle, u64 dump_size,
5602 struct pt_regs *regs)
5604 /* Case of a kernel thread, nothing to dump */
5607 perf_output_put(handle, size);
5616 * - the size requested by user or the best one we can fit
5617 * in to the sample max size
5619 * - user stack dump data
5621 * - the actual dumped size
5625 perf_output_put(handle, dump_size);
5628 sp = perf_user_stack_pointer(regs);
5629 rem = __output_copy_user(handle, (void *) sp, dump_size);
5630 dyn_size = dump_size - rem;
5632 perf_output_skip(handle, rem);
5635 perf_output_put(handle, dyn_size);
5639 static void __perf_event_header__init_id(struct perf_event_header *header,
5640 struct perf_sample_data *data,
5641 struct perf_event *event)
5643 u64 sample_type = event->attr.sample_type;
5645 data->type = sample_type;
5646 header->size += event->id_header_size;
5648 if (sample_type & PERF_SAMPLE_TID) {
5649 /* namespace issues */
5650 data->tid_entry.pid = perf_event_pid(event, current);
5651 data->tid_entry.tid = perf_event_tid(event, current);
5654 if (sample_type & PERF_SAMPLE_TIME)
5655 data->time = perf_event_clock(event);
5657 if (sample_type & (PERF_SAMPLE_ID | PERF_SAMPLE_IDENTIFIER))
5658 data->id = primary_event_id(event);
5660 if (sample_type & PERF_SAMPLE_STREAM_ID)
5661 data->stream_id = event->id;
5663 if (sample_type & PERF_SAMPLE_CPU) {
5664 data->cpu_entry.cpu = raw_smp_processor_id();
5665 data->cpu_entry.reserved = 0;
5669 void perf_event_header__init_id(struct perf_event_header *header,
5670 struct perf_sample_data *data,
5671 struct perf_event *event)
5673 if (event->attr.sample_id_all)
5674 __perf_event_header__init_id(header, data, event);
5677 static void __perf_event__output_id_sample(struct perf_output_handle *handle,
5678 struct perf_sample_data *data)
5680 u64 sample_type = data->type;
5682 if (sample_type & PERF_SAMPLE_TID)
5683 perf_output_put(handle, data->tid_entry);
5685 if (sample_type & PERF_SAMPLE_TIME)
5686 perf_output_put(handle, data->time);
5688 if (sample_type & PERF_SAMPLE_ID)
5689 perf_output_put(handle, data->id);
5691 if (sample_type & PERF_SAMPLE_STREAM_ID)
5692 perf_output_put(handle, data->stream_id);
5694 if (sample_type & PERF_SAMPLE_CPU)
5695 perf_output_put(handle, data->cpu_entry);
5697 if (sample_type & PERF_SAMPLE_IDENTIFIER)
5698 perf_output_put(handle, data->id);
5701 void perf_event__output_id_sample(struct perf_event *event,
5702 struct perf_output_handle *handle,
5703 struct perf_sample_data *sample)
5705 if (event->attr.sample_id_all)
5706 __perf_event__output_id_sample(handle, sample);
5709 static void perf_output_read_one(struct perf_output_handle *handle,
5710 struct perf_event *event,
5711 u64 enabled, u64 running)
5713 u64 read_format = event->attr.read_format;
5717 values[n++] = perf_event_count(event);
5718 if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED) {
5719 values[n++] = enabled +
5720 atomic64_read(&event->child_total_time_enabled);
5722 if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING) {
5723 values[n++] = running +
5724 atomic64_read(&event->child_total_time_running);
5726 if (read_format & PERF_FORMAT_ID)
5727 values[n++] = primary_event_id(event);
5729 __output_copy(handle, values, n * sizeof(u64));
5733 * XXX PERF_FORMAT_GROUP vs inherited events seems difficult.
5735 static void perf_output_read_group(struct perf_output_handle *handle,
5736 struct perf_event *event,
5737 u64 enabled, u64 running)
5739 struct perf_event *leader = event->group_leader, *sub;
5740 u64 read_format = event->attr.read_format;
5744 values[n++] = 1 + leader->nr_siblings;
5746 if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED)
5747 values[n++] = enabled;
5749 if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING)
5750 values[n++] = running;
5752 if (leader != event)
5753 leader->pmu->read(leader);
5755 values[n++] = perf_event_count(leader);
5756 if (read_format & PERF_FORMAT_ID)
5757 values[n++] = primary_event_id(leader);
5759 __output_copy(handle, values, n * sizeof(u64));
5761 list_for_each_entry(sub, &leader->sibling_list, group_entry) {
5764 if ((sub != event) &&
5765 (sub->state == PERF_EVENT_STATE_ACTIVE))
5766 sub->pmu->read(sub);
5768 values[n++] = perf_event_count(sub);
5769 if (read_format & PERF_FORMAT_ID)
5770 values[n++] = primary_event_id(sub);
5772 __output_copy(handle, values, n * sizeof(u64));
5776 #define PERF_FORMAT_TOTAL_TIMES (PERF_FORMAT_TOTAL_TIME_ENABLED|\
5777 PERF_FORMAT_TOTAL_TIME_RUNNING)
5779 static void perf_output_read(struct perf_output_handle *handle,
5780 struct perf_event *event)
5782 u64 enabled = 0, running = 0, now;
5783 u64 read_format = event->attr.read_format;
5786 * compute total_time_enabled, total_time_running
5787 * based on snapshot values taken when the event
5788 * was last scheduled in.
5790 * we cannot simply called update_context_time()
5791 * because of locking issue as we are called in
5794 if (read_format & PERF_FORMAT_TOTAL_TIMES)
5795 calc_timer_values(event, &now, &enabled, &running);
5797 if (event->attr.read_format & PERF_FORMAT_GROUP)
5798 perf_output_read_group(handle, event, enabled, running);
5800 perf_output_read_one(handle, event, enabled, running);
5803 void perf_output_sample(struct perf_output_handle *handle,
5804 struct perf_event_header *header,
5805 struct perf_sample_data *data,
5806 struct perf_event *event)
5808 u64 sample_type = data->type;
5810 perf_output_put(handle, *header);
5812 if (sample_type & PERF_SAMPLE_IDENTIFIER)
5813 perf_output_put(handle, data->id);
5815 if (sample_type & PERF_SAMPLE_IP)
5816 perf_output_put(handle, data->ip);
5818 if (sample_type & PERF_SAMPLE_TID)
5819 perf_output_put(handle, data->tid_entry);
5821 if (sample_type & PERF_SAMPLE_TIME)
5822 perf_output_put(handle, data->time);
5824 if (sample_type & PERF_SAMPLE_ADDR)
5825 perf_output_put(handle, data->addr);
5827 if (sample_type & PERF_SAMPLE_ID)
5828 perf_output_put(handle, data->id);
5830 if (sample_type & PERF_SAMPLE_STREAM_ID)
5831 perf_output_put(handle, data->stream_id);
5833 if (sample_type & PERF_SAMPLE_CPU)
5834 perf_output_put(handle, data->cpu_entry);
5836 if (sample_type & PERF_SAMPLE_PERIOD)
5837 perf_output_put(handle, data->period);
5839 if (sample_type & PERF_SAMPLE_READ)
5840 perf_output_read(handle, event);
5842 if (sample_type & PERF_SAMPLE_CALLCHAIN) {
5843 if (data->callchain) {
5846 if (data->callchain)
5847 size += data->callchain->nr;
5849 size *= sizeof(u64);
5851 __output_copy(handle, data->callchain, size);
5854 perf_output_put(handle, nr);
5858 if (sample_type & PERF_SAMPLE_RAW) {
5859 struct perf_raw_record *raw = data->raw;
5862 struct perf_raw_frag *frag = &raw->frag;
5864 perf_output_put(handle, raw->size);
5867 __output_custom(handle, frag->copy,
5868 frag->data, frag->size);
5870 __output_copy(handle, frag->data,
5873 if (perf_raw_frag_last(frag))
5878 __output_skip(handle, NULL, frag->pad);
5884 .size = sizeof(u32),
5887 perf_output_put(handle, raw);
5891 if (sample_type & PERF_SAMPLE_BRANCH_STACK) {
5892 if (data->br_stack) {
5895 size = data->br_stack->nr
5896 * sizeof(struct perf_branch_entry);
5898 perf_output_put(handle, data->br_stack->nr);
5899 perf_output_copy(handle, data->br_stack->entries, size);
5902 * we always store at least the value of nr
5905 perf_output_put(handle, nr);
5909 if (sample_type & PERF_SAMPLE_REGS_USER) {
5910 u64 abi = data->regs_user.abi;
5913 * If there are no regs to dump, notice it through
5914 * first u64 being zero (PERF_SAMPLE_REGS_ABI_NONE).
5916 perf_output_put(handle, abi);
5919 u64 mask = event->attr.sample_regs_user;
5920 perf_output_sample_regs(handle,
5921 data->regs_user.regs,
5926 if (sample_type & PERF_SAMPLE_STACK_USER) {
5927 perf_output_sample_ustack(handle,
5928 data->stack_user_size,
5929 data->regs_user.regs);
5932 if (sample_type & PERF_SAMPLE_WEIGHT)
5933 perf_output_put(handle, data->weight);
5935 if (sample_type & PERF_SAMPLE_DATA_SRC)
5936 perf_output_put(handle, data->data_src.val);
5938 if (sample_type & PERF_SAMPLE_TRANSACTION)
5939 perf_output_put(handle, data->txn);
5941 if (sample_type & PERF_SAMPLE_REGS_INTR) {
5942 u64 abi = data->regs_intr.abi;
5944 * If there are no regs to dump, notice it through
5945 * first u64 being zero (PERF_SAMPLE_REGS_ABI_NONE).
5947 perf_output_put(handle, abi);
5950 u64 mask = event->attr.sample_regs_intr;
5952 perf_output_sample_regs(handle,
5953 data->regs_intr.regs,
5958 if (!event->attr.watermark) {
5959 int wakeup_events = event->attr.wakeup_events;
5961 if (wakeup_events) {
5962 struct ring_buffer *rb = handle->rb;
5963 int events = local_inc_return(&rb->events);
5965 if (events >= wakeup_events) {
5966 local_sub(wakeup_events, &rb->events);
5967 local_inc(&rb->wakeup);
5973 void perf_prepare_sample(struct perf_event_header *header,
5974 struct perf_sample_data *data,
5975 struct perf_event *event,
5976 struct pt_regs *regs)
5978 u64 sample_type = event->attr.sample_type;
5980 header->type = PERF_RECORD_SAMPLE;
5981 header->size = sizeof(*header) + event->header_size;
5984 header->misc |= perf_misc_flags(regs);
5986 __perf_event_header__init_id(header, data, event);
5988 if (sample_type & PERF_SAMPLE_IP)
5989 data->ip = perf_instruction_pointer(regs);
5991 if (sample_type & PERF_SAMPLE_CALLCHAIN) {
5994 data->callchain = perf_callchain(event, regs);
5996 if (data->callchain)
5997 size += data->callchain->nr;
5999 header->size += size * sizeof(u64);
6002 if (sample_type & PERF_SAMPLE_RAW) {
6003 struct perf_raw_record *raw = data->raw;
6007 struct perf_raw_frag *frag = &raw->frag;
6012 if (perf_raw_frag_last(frag))
6017 size = round_up(sum + sizeof(u32), sizeof(u64));
6018 raw->size = size - sizeof(u32);
6019 frag->pad = raw->size - sum;
6024 header->size += size;
6027 if (sample_type & PERF_SAMPLE_BRANCH_STACK) {
6028 int size = sizeof(u64); /* nr */
6029 if (data->br_stack) {
6030 size += data->br_stack->nr
6031 * sizeof(struct perf_branch_entry);
6033 header->size += size;
6036 if (sample_type & (PERF_SAMPLE_REGS_USER | PERF_SAMPLE_STACK_USER))
6037 perf_sample_regs_user(&data->regs_user, regs,
6038 &data->regs_user_copy);
6040 if (sample_type & PERF_SAMPLE_REGS_USER) {
6041 /* regs dump ABI info */
6042 int size = sizeof(u64);
6044 if (data->regs_user.regs) {
6045 u64 mask = event->attr.sample_regs_user;
6046 size += hweight64(mask) * sizeof(u64);
6049 header->size += size;
6052 if (sample_type & PERF_SAMPLE_STACK_USER) {
6054 * Either we need PERF_SAMPLE_STACK_USER bit to be allways
6055 * processed as the last one or have additional check added
6056 * in case new sample type is added, because we could eat
6057 * up the rest of the sample size.
6059 u16 stack_size = event->attr.sample_stack_user;
6060 u16 size = sizeof(u64);
6062 stack_size = perf_sample_ustack_size(stack_size, header->size,
6063 data->regs_user.regs);
6066 * If there is something to dump, add space for the dump
6067 * itself and for the field that tells the dynamic size,
6068 * which is how many have been actually dumped.
6071 size += sizeof(u64) + stack_size;
6073 data->stack_user_size = stack_size;
6074 header->size += size;
6077 if (sample_type & PERF_SAMPLE_REGS_INTR) {
6078 /* regs dump ABI info */
6079 int size = sizeof(u64);
6081 perf_sample_regs_intr(&data->regs_intr, regs);
6083 if (data->regs_intr.regs) {
6084 u64 mask = event->attr.sample_regs_intr;
6086 size += hweight64(mask) * sizeof(u64);
6089 header->size += size;
6093 static void __always_inline
6094 __perf_event_output(struct perf_event *event,
6095 struct perf_sample_data *data,
6096 struct pt_regs *regs,
6097 int (*output_begin)(struct perf_output_handle *,
6098 struct perf_event *,
6101 struct perf_output_handle handle;
6102 struct perf_event_header header;
6104 /* protect the callchain buffers */
6107 perf_prepare_sample(&header, data, event, regs);
6109 if (output_begin(&handle, event, header.size))
6112 perf_output_sample(&handle, &header, data, event);
6114 perf_output_end(&handle);
6121 perf_event_output_forward(struct perf_event *event,
6122 struct perf_sample_data *data,
6123 struct pt_regs *regs)
6125 __perf_event_output(event, data, regs, perf_output_begin_forward);
6129 perf_event_output_backward(struct perf_event *event,
6130 struct perf_sample_data *data,
6131 struct pt_regs *regs)
6133 __perf_event_output(event, data, regs, perf_output_begin_backward);
6137 perf_event_output(struct perf_event *event,
6138 struct perf_sample_data *data,
6139 struct pt_regs *regs)
6141 __perf_event_output(event, data, regs, perf_output_begin);
6148 struct perf_read_event {
6149 struct perf_event_header header;
6156 perf_event_read_event(struct perf_event *event,
6157 struct task_struct *task)
6159 struct perf_output_handle handle;
6160 struct perf_sample_data sample;
6161 struct perf_read_event read_event = {
6163 .type = PERF_RECORD_READ,
6165 .size = sizeof(read_event) + event->read_size,
6167 .pid = perf_event_pid(event, task),
6168 .tid = perf_event_tid(event, task),
6172 perf_event_header__init_id(&read_event.header, &sample, event);
6173 ret = perf_output_begin(&handle, event, read_event.header.size);
6177 perf_output_put(&handle, read_event);
6178 perf_output_read(&handle, event);
6179 perf_event__output_id_sample(event, &handle, &sample);
6181 perf_output_end(&handle);
6184 typedef void (perf_iterate_f)(struct perf_event *event, void *data);
6187 perf_iterate_ctx(struct perf_event_context *ctx,
6188 perf_iterate_f output,
6189 void *data, bool all)
6191 struct perf_event *event;
6193 list_for_each_entry_rcu(event, &ctx->event_list, event_entry) {
6195 if (event->state < PERF_EVENT_STATE_INACTIVE)
6197 if (!event_filter_match(event))
6201 output(event, data);
6205 static void perf_iterate_sb_cpu(perf_iterate_f output, void *data)
6207 struct pmu_event_list *pel = this_cpu_ptr(&pmu_sb_events);
6208 struct perf_event *event;
6210 list_for_each_entry_rcu(event, &pel->list, sb_list) {
6212 * Skip events that are not fully formed yet; ensure that
6213 * if we observe event->ctx, both event and ctx will be
6214 * complete enough. See perf_install_in_context().
6216 if (!smp_load_acquire(&event->ctx))
6219 if (event->state < PERF_EVENT_STATE_INACTIVE)
6221 if (!event_filter_match(event))
6223 output(event, data);
6228 * Iterate all events that need to receive side-band events.
6230 * For new callers; ensure that account_pmu_sb_event() includes
6231 * your event, otherwise it might not get delivered.
6234 perf_iterate_sb(perf_iterate_f output, void *data,
6235 struct perf_event_context *task_ctx)
6237 struct perf_event_context *ctx;
6244 * If we have task_ctx != NULL we only notify the task context itself.
6245 * The task_ctx is set only for EXIT events before releasing task
6249 perf_iterate_ctx(task_ctx, output, data, false);
6253 perf_iterate_sb_cpu(output, data);
6255 for_each_task_context_nr(ctxn) {
6256 ctx = rcu_dereference(current->perf_event_ctxp[ctxn]);
6258 perf_iterate_ctx(ctx, output, data, false);
6266 * Clear all file-based filters at exec, they'll have to be
6267 * re-instated when/if these objects are mmapped again.
6269 static void perf_event_addr_filters_exec(struct perf_event *event, void *data)
6271 struct perf_addr_filters_head *ifh = perf_event_addr_filters(event);
6272 struct perf_addr_filter *filter;
6273 unsigned int restart = 0, count = 0;
6274 unsigned long flags;
6276 if (!has_addr_filter(event))
6279 raw_spin_lock_irqsave(&ifh->lock, flags);
6280 list_for_each_entry(filter, &ifh->list, entry) {
6281 if (filter->inode) {
6282 event->addr_filters_offs[count] = 0;
6290 event->addr_filters_gen++;
6291 raw_spin_unlock_irqrestore(&ifh->lock, flags);
6294 perf_event_stop(event, 1);
6297 void perf_event_exec(void)
6299 struct perf_event_context *ctx;
6303 for_each_task_context_nr(ctxn) {
6304 ctx = current->perf_event_ctxp[ctxn];
6308 perf_event_enable_on_exec(ctxn);
6310 perf_iterate_ctx(ctx, perf_event_addr_filters_exec, NULL,
6316 struct remote_output {
6317 struct ring_buffer *rb;
6321 static void __perf_event_output_stop(struct perf_event *event, void *data)
6323 struct perf_event *parent = event->parent;
6324 struct remote_output *ro = data;
6325 struct ring_buffer *rb = ro->rb;
6326 struct stop_event_data sd = {
6330 if (!has_aux(event))
6337 * In case of inheritance, it will be the parent that links to the
6338 * ring-buffer, but it will be the child that's actually using it.
6340 * We are using event::rb to determine if the event should be stopped,
6341 * however this may race with ring_buffer_attach() (through set_output),
6342 * which will make us skip the event that actually needs to be stopped.
6343 * So ring_buffer_attach() has to stop an aux event before re-assigning
6346 if (rcu_dereference(parent->rb) == rb)
6347 ro->err = __perf_event_stop(&sd);
6350 static int __perf_pmu_output_stop(void *info)
6352 struct perf_event *event = info;
6353 struct pmu *pmu = event->pmu;
6354 struct perf_cpu_context *cpuctx = this_cpu_ptr(pmu->pmu_cpu_context);
6355 struct remote_output ro = {
6360 perf_iterate_ctx(&cpuctx->ctx, __perf_event_output_stop, &ro, false);
6361 if (cpuctx->task_ctx)
6362 perf_iterate_ctx(cpuctx->task_ctx, __perf_event_output_stop,
6369 static void perf_pmu_output_stop(struct perf_event *event)
6371 struct perf_event *iter;
6376 list_for_each_entry_rcu(iter, &event->rb->event_list, rb_entry) {
6378 * For per-CPU events, we need to make sure that neither they
6379 * nor their children are running; for cpu==-1 events it's
6380 * sufficient to stop the event itself if it's active, since
6381 * it can't have children.
6385 cpu = READ_ONCE(iter->oncpu);
6390 err = cpu_function_call(cpu, __perf_pmu_output_stop, event);
6391 if (err == -EAGAIN) {
6400 * task tracking -- fork/exit
6402 * enabled by: attr.comm | attr.mmap | attr.mmap2 | attr.mmap_data | attr.task
6405 struct perf_task_event {
6406 struct task_struct *task;
6407 struct perf_event_context *task_ctx;
6410 struct perf_event_header header;
6420 static int perf_event_task_match(struct perf_event *event)
6422 return event->attr.comm || event->attr.mmap ||
6423 event->attr.mmap2 || event->attr.mmap_data ||
6427 static void perf_event_task_output(struct perf_event *event,
6430 struct perf_task_event *task_event = data;
6431 struct perf_output_handle handle;
6432 struct perf_sample_data sample;
6433 struct task_struct *task = task_event->task;
6434 int ret, size = task_event->event_id.header.size;
6436 if (!perf_event_task_match(event))
6439 perf_event_header__init_id(&task_event->event_id.header, &sample, event);
6441 ret = perf_output_begin(&handle, event,
6442 task_event->event_id.header.size);
6446 task_event->event_id.pid = perf_event_pid(event, task);
6447 task_event->event_id.ppid = perf_event_pid(event, current);
6449 task_event->event_id.tid = perf_event_tid(event, task);
6450 task_event->event_id.ptid = perf_event_tid(event, current);
6452 task_event->event_id.time = perf_event_clock(event);
6454 perf_output_put(&handle, task_event->event_id);
6456 perf_event__output_id_sample(event, &handle, &sample);
6458 perf_output_end(&handle);
6460 task_event->event_id.header.size = size;
6463 static void perf_event_task(struct task_struct *task,
6464 struct perf_event_context *task_ctx,
6467 struct perf_task_event task_event;
6469 if (!atomic_read(&nr_comm_events) &&
6470 !atomic_read(&nr_mmap_events) &&
6471 !atomic_read(&nr_task_events))
6474 task_event = (struct perf_task_event){
6476 .task_ctx = task_ctx,
6479 .type = new ? PERF_RECORD_FORK : PERF_RECORD_EXIT,
6481 .size = sizeof(task_event.event_id),
6491 perf_iterate_sb(perf_event_task_output,
6496 void perf_event_fork(struct task_struct *task)
6498 perf_event_task(task, NULL, 1);
6499 perf_event_namespaces(task);
6506 struct perf_comm_event {
6507 struct task_struct *task;
6512 struct perf_event_header header;
6519 static int perf_event_comm_match(struct perf_event *event)
6521 return event->attr.comm;
6524 static void perf_event_comm_output(struct perf_event *event,
6527 struct perf_comm_event *comm_event = data;
6528 struct perf_output_handle handle;
6529 struct perf_sample_data sample;
6530 int size = comm_event->event_id.header.size;
6533 if (!perf_event_comm_match(event))
6536 perf_event_header__init_id(&comm_event->event_id.header, &sample, event);
6537 ret = perf_output_begin(&handle, event,
6538 comm_event->event_id.header.size);
6543 comm_event->event_id.pid = perf_event_pid(event, comm_event->task);
6544 comm_event->event_id.tid = perf_event_tid(event, comm_event->task);
6546 perf_output_put(&handle, comm_event->event_id);
6547 __output_copy(&handle, comm_event->comm,
6548 comm_event->comm_size);
6550 perf_event__output_id_sample(event, &handle, &sample);
6552 perf_output_end(&handle);
6554 comm_event->event_id.header.size = size;
6557 static void perf_event_comm_event(struct perf_comm_event *comm_event)
6559 char comm[TASK_COMM_LEN];
6562 memset(comm, 0, sizeof(comm));
6563 strlcpy(comm, comm_event->task->comm, sizeof(comm));
6564 size = ALIGN(strlen(comm)+1, sizeof(u64));
6566 comm_event->comm = comm;
6567 comm_event->comm_size = size;
6569 comm_event->event_id.header.size = sizeof(comm_event->event_id) + size;
6571 perf_iterate_sb(perf_event_comm_output,
6576 void perf_event_comm(struct task_struct *task, bool exec)
6578 struct perf_comm_event comm_event;
6580 if (!atomic_read(&nr_comm_events))
6583 comm_event = (struct perf_comm_event){
6589 .type = PERF_RECORD_COMM,
6590 .misc = exec ? PERF_RECORD_MISC_COMM_EXEC : 0,
6598 perf_event_comm_event(&comm_event);
6602 * namespaces tracking
6605 struct perf_namespaces_event {
6606 struct task_struct *task;
6609 struct perf_event_header header;
6614 struct perf_ns_link_info link_info[NR_NAMESPACES];
6618 static int perf_event_namespaces_match(struct perf_event *event)
6620 return event->attr.namespaces;
6623 static void perf_event_namespaces_output(struct perf_event *event,
6626 struct perf_namespaces_event *namespaces_event = data;
6627 struct perf_output_handle handle;
6628 struct perf_sample_data sample;
6631 if (!perf_event_namespaces_match(event))
6634 perf_event_header__init_id(&namespaces_event->event_id.header,
6636 ret = perf_output_begin(&handle, event,
6637 namespaces_event->event_id.header.size);
6641 namespaces_event->event_id.pid = perf_event_pid(event,
6642 namespaces_event->task);
6643 namespaces_event->event_id.tid = perf_event_tid(event,
6644 namespaces_event->task);
6646 perf_output_put(&handle, namespaces_event->event_id);
6648 perf_event__output_id_sample(event, &handle, &sample);
6650 perf_output_end(&handle);
6653 static void perf_fill_ns_link_info(struct perf_ns_link_info *ns_link_info,
6654 struct task_struct *task,
6655 const struct proc_ns_operations *ns_ops)
6657 struct path ns_path;
6658 struct inode *ns_inode;
6661 error = ns_get_path(&ns_path, task, ns_ops);
6663 ns_inode = ns_path.dentry->d_inode;
6664 ns_link_info->dev = new_encode_dev(ns_inode->i_sb->s_dev);
6665 ns_link_info->ino = ns_inode->i_ino;
6669 void perf_event_namespaces(struct task_struct *task)
6671 struct perf_namespaces_event namespaces_event;
6672 struct perf_ns_link_info *ns_link_info;
6674 if (!atomic_read(&nr_namespaces_events))
6677 namespaces_event = (struct perf_namespaces_event){
6681 .type = PERF_RECORD_NAMESPACES,
6683 .size = sizeof(namespaces_event.event_id),
6687 .nr_namespaces = NR_NAMESPACES,
6688 /* .link_info[NR_NAMESPACES] */
6692 ns_link_info = namespaces_event.event_id.link_info;
6694 perf_fill_ns_link_info(&ns_link_info[MNT_NS_INDEX],
6695 task, &mntns_operations);
6697 #ifdef CONFIG_USER_NS
6698 perf_fill_ns_link_info(&ns_link_info[USER_NS_INDEX],
6699 task, &userns_operations);
6701 #ifdef CONFIG_NET_NS
6702 perf_fill_ns_link_info(&ns_link_info[NET_NS_INDEX],
6703 task, &netns_operations);
6705 #ifdef CONFIG_UTS_NS
6706 perf_fill_ns_link_info(&ns_link_info[UTS_NS_INDEX],
6707 task, &utsns_operations);
6709 #ifdef CONFIG_IPC_NS
6710 perf_fill_ns_link_info(&ns_link_info[IPC_NS_INDEX],
6711 task, &ipcns_operations);
6713 #ifdef CONFIG_PID_NS
6714 perf_fill_ns_link_info(&ns_link_info[PID_NS_INDEX],
6715 task, &pidns_operations);
6717 #ifdef CONFIG_CGROUPS
6718 perf_fill_ns_link_info(&ns_link_info[CGROUP_NS_INDEX],
6719 task, &cgroupns_operations);
6722 perf_iterate_sb(perf_event_namespaces_output,
6731 struct perf_mmap_event {
6732 struct vm_area_struct *vma;
6734 const char *file_name;
6742 struct perf_event_header header;
6752 static int perf_event_mmap_match(struct perf_event *event,
6755 struct perf_mmap_event *mmap_event = data;
6756 struct vm_area_struct *vma = mmap_event->vma;
6757 int executable = vma->vm_flags & VM_EXEC;
6759 return (!executable && event->attr.mmap_data) ||
6760 (executable && (event->attr.mmap || event->attr.mmap2));
6763 static void perf_event_mmap_output(struct perf_event *event,
6766 struct perf_mmap_event *mmap_event = data;
6767 struct perf_output_handle handle;
6768 struct perf_sample_data sample;
6769 int size = mmap_event->event_id.header.size;
6772 if (!perf_event_mmap_match(event, data))
6775 if (event->attr.mmap2) {
6776 mmap_event->event_id.header.type = PERF_RECORD_MMAP2;
6777 mmap_event->event_id.header.size += sizeof(mmap_event->maj);
6778 mmap_event->event_id.header.size += sizeof(mmap_event->min);
6779 mmap_event->event_id.header.size += sizeof(mmap_event->ino);
6780 mmap_event->event_id.header.size += sizeof(mmap_event->ino_generation);
6781 mmap_event->event_id.header.size += sizeof(mmap_event->prot);
6782 mmap_event->event_id.header.size += sizeof(mmap_event->flags);
6785 perf_event_header__init_id(&mmap_event->event_id.header, &sample, event);
6786 ret = perf_output_begin(&handle, event,
6787 mmap_event->event_id.header.size);
6791 mmap_event->event_id.pid = perf_event_pid(event, current);
6792 mmap_event->event_id.tid = perf_event_tid(event, current);
6794 perf_output_put(&handle, mmap_event->event_id);
6796 if (event->attr.mmap2) {
6797 perf_output_put(&handle, mmap_event->maj);
6798 perf_output_put(&handle, mmap_event->min);
6799 perf_output_put(&handle, mmap_event->ino);
6800 perf_output_put(&handle, mmap_event->ino_generation);
6801 perf_output_put(&handle, mmap_event->prot);
6802 perf_output_put(&handle, mmap_event->flags);
6805 __output_copy(&handle, mmap_event->file_name,
6806 mmap_event->file_size);
6808 perf_event__output_id_sample(event, &handle, &sample);
6810 perf_output_end(&handle);
6812 mmap_event->event_id.header.size = size;
6815 static void perf_event_mmap_event(struct perf_mmap_event *mmap_event)
6817 struct vm_area_struct *vma = mmap_event->vma;
6818 struct file *file = vma->vm_file;
6819 int maj = 0, min = 0;
6820 u64 ino = 0, gen = 0;
6821 u32 prot = 0, flags = 0;
6827 if (vma->vm_flags & VM_READ)
6829 if (vma->vm_flags & VM_WRITE)
6831 if (vma->vm_flags & VM_EXEC)
6834 if (vma->vm_flags & VM_MAYSHARE)
6837 flags = MAP_PRIVATE;
6839 if (vma->vm_flags & VM_DENYWRITE)
6840 flags |= MAP_DENYWRITE;
6841 if (vma->vm_flags & VM_MAYEXEC)
6842 flags |= MAP_EXECUTABLE;
6843 if (vma->vm_flags & VM_LOCKED)
6844 flags |= MAP_LOCKED;
6845 if (vma->vm_flags & VM_HUGETLB)
6846 flags |= MAP_HUGETLB;
6849 struct inode *inode;
6852 buf = kmalloc(PATH_MAX, GFP_KERNEL);
6858 * d_path() works from the end of the rb backwards, so we
6859 * need to add enough zero bytes after the string to handle
6860 * the 64bit alignment we do later.
6862 name = file_path(file, buf, PATH_MAX - sizeof(u64));
6867 inode = file_inode(vma->vm_file);
6868 dev = inode->i_sb->s_dev;
6870 gen = inode->i_generation;
6876 if (vma->vm_ops && vma->vm_ops->name) {
6877 name = (char *) vma->vm_ops->name(vma);
6882 name = (char *)arch_vma_name(vma);
6886 if (vma->vm_start <= vma->vm_mm->start_brk &&
6887 vma->vm_end >= vma->vm_mm->brk) {
6891 if (vma->vm_start <= vma->vm_mm->start_stack &&
6892 vma->vm_end >= vma->vm_mm->start_stack) {
6902 strlcpy(tmp, name, sizeof(tmp));
6906 * Since our buffer works in 8 byte units we need to align our string
6907 * size to a multiple of 8. However, we must guarantee the tail end is
6908 * zero'd out to avoid leaking random bits to userspace.
6910 size = strlen(name)+1;
6911 while (!IS_ALIGNED(size, sizeof(u64)))
6912 name[size++] = '\0';
6914 mmap_event->file_name = name;
6915 mmap_event->file_size = size;
6916 mmap_event->maj = maj;
6917 mmap_event->min = min;
6918 mmap_event->ino = ino;
6919 mmap_event->ino_generation = gen;
6920 mmap_event->prot = prot;
6921 mmap_event->flags = flags;
6923 if (!(vma->vm_flags & VM_EXEC))
6924 mmap_event->event_id.header.misc |= PERF_RECORD_MISC_MMAP_DATA;
6926 mmap_event->event_id.header.size = sizeof(mmap_event->event_id) + size;
6928 perf_iterate_sb(perf_event_mmap_output,
6936 * Check whether inode and address range match filter criteria.
6938 static bool perf_addr_filter_match(struct perf_addr_filter *filter,
6939 struct file *file, unsigned long offset,
6942 if (filter->inode != file_inode(file))
6945 if (filter->offset > offset + size)
6948 if (filter->offset + filter->size < offset)
6954 static void __perf_addr_filters_adjust(struct perf_event *event, void *data)
6956 struct perf_addr_filters_head *ifh = perf_event_addr_filters(event);
6957 struct vm_area_struct *vma = data;
6958 unsigned long off = vma->vm_pgoff << PAGE_SHIFT, flags;
6959 struct file *file = vma->vm_file;
6960 struct perf_addr_filter *filter;
6961 unsigned int restart = 0, count = 0;
6963 if (!has_addr_filter(event))
6969 raw_spin_lock_irqsave(&ifh->lock, flags);
6970 list_for_each_entry(filter, &ifh->list, entry) {
6971 if (perf_addr_filter_match(filter, file, off,
6972 vma->vm_end - vma->vm_start)) {
6973 event->addr_filters_offs[count] = vma->vm_start;
6981 event->addr_filters_gen++;
6982 raw_spin_unlock_irqrestore(&ifh->lock, flags);
6985 perf_event_stop(event, 1);
6989 * Adjust all task's events' filters to the new vma
6991 static void perf_addr_filters_adjust(struct vm_area_struct *vma)
6993 struct perf_event_context *ctx;
6997 * Data tracing isn't supported yet and as such there is no need
6998 * to keep track of anything that isn't related to executable code:
7000 if (!(vma->vm_flags & VM_EXEC))
7004 for_each_task_context_nr(ctxn) {
7005 ctx = rcu_dereference(current->perf_event_ctxp[ctxn]);
7009 perf_iterate_ctx(ctx, __perf_addr_filters_adjust, vma, true);
7014 void perf_event_mmap(struct vm_area_struct *vma)
7016 struct perf_mmap_event mmap_event;
7018 if (!atomic_read(&nr_mmap_events))
7021 mmap_event = (struct perf_mmap_event){
7027 .type = PERF_RECORD_MMAP,
7028 .misc = PERF_RECORD_MISC_USER,
7033 .start = vma->vm_start,
7034 .len = vma->vm_end - vma->vm_start,
7035 .pgoff = (u64)vma->vm_pgoff << PAGE_SHIFT,
7037 /* .maj (attr_mmap2 only) */
7038 /* .min (attr_mmap2 only) */
7039 /* .ino (attr_mmap2 only) */
7040 /* .ino_generation (attr_mmap2 only) */
7041 /* .prot (attr_mmap2 only) */
7042 /* .flags (attr_mmap2 only) */
7045 perf_addr_filters_adjust(vma);
7046 perf_event_mmap_event(&mmap_event);
7049 void perf_event_aux_event(struct perf_event *event, unsigned long head,
7050 unsigned long size, u64 flags)
7052 struct perf_output_handle handle;
7053 struct perf_sample_data sample;
7054 struct perf_aux_event {
7055 struct perf_event_header header;
7061 .type = PERF_RECORD_AUX,
7063 .size = sizeof(rec),
7071 perf_event_header__init_id(&rec.header, &sample, event);
7072 ret = perf_output_begin(&handle, event, rec.header.size);
7077 perf_output_put(&handle, rec);
7078 perf_event__output_id_sample(event, &handle, &sample);
7080 perf_output_end(&handle);
7084 * Lost/dropped samples logging
7086 void perf_log_lost_samples(struct perf_event *event, u64 lost)
7088 struct perf_output_handle handle;
7089 struct perf_sample_data sample;
7093 struct perf_event_header header;
7095 } lost_samples_event = {
7097 .type = PERF_RECORD_LOST_SAMPLES,
7099 .size = sizeof(lost_samples_event),
7104 perf_event_header__init_id(&lost_samples_event.header, &sample, event);
7106 ret = perf_output_begin(&handle, event,
7107 lost_samples_event.header.size);
7111 perf_output_put(&handle, lost_samples_event);
7112 perf_event__output_id_sample(event, &handle, &sample);
7113 perf_output_end(&handle);
7117 * context_switch tracking
7120 struct perf_switch_event {
7121 struct task_struct *task;
7122 struct task_struct *next_prev;
7125 struct perf_event_header header;
7131 static int perf_event_switch_match(struct perf_event *event)
7133 return event->attr.context_switch;
7136 static void perf_event_switch_output(struct perf_event *event, void *data)
7138 struct perf_switch_event *se = data;
7139 struct perf_output_handle handle;
7140 struct perf_sample_data sample;
7143 if (!perf_event_switch_match(event))
7146 /* Only CPU-wide events are allowed to see next/prev pid/tid */
7147 if (event->ctx->task) {
7148 se->event_id.header.type = PERF_RECORD_SWITCH;
7149 se->event_id.header.size = sizeof(se->event_id.header);
7151 se->event_id.header.type = PERF_RECORD_SWITCH_CPU_WIDE;
7152 se->event_id.header.size = sizeof(se->event_id);
7153 se->event_id.next_prev_pid =
7154 perf_event_pid(event, se->next_prev);
7155 se->event_id.next_prev_tid =
7156 perf_event_tid(event, se->next_prev);
7159 perf_event_header__init_id(&se->event_id.header, &sample, event);
7161 ret = perf_output_begin(&handle, event, se->event_id.header.size);
7165 if (event->ctx->task)
7166 perf_output_put(&handle, se->event_id.header);
7168 perf_output_put(&handle, se->event_id);
7170 perf_event__output_id_sample(event, &handle, &sample);
7172 perf_output_end(&handle);
7175 static void perf_event_switch(struct task_struct *task,
7176 struct task_struct *next_prev, bool sched_in)
7178 struct perf_switch_event switch_event;
7180 /* N.B. caller checks nr_switch_events != 0 */
7182 switch_event = (struct perf_switch_event){
7184 .next_prev = next_prev,
7188 .misc = sched_in ? 0 : PERF_RECORD_MISC_SWITCH_OUT,
7191 /* .next_prev_pid */
7192 /* .next_prev_tid */
7196 perf_iterate_sb(perf_event_switch_output,
7202 * IRQ throttle logging
7205 static void perf_log_throttle(struct perf_event *event, int enable)
7207 struct perf_output_handle handle;
7208 struct perf_sample_data sample;
7212 struct perf_event_header header;
7216 } throttle_event = {
7218 .type = PERF_RECORD_THROTTLE,
7220 .size = sizeof(throttle_event),
7222 .time = perf_event_clock(event),
7223 .id = primary_event_id(event),
7224 .stream_id = event->id,
7228 throttle_event.header.type = PERF_RECORD_UNTHROTTLE;
7230 perf_event_header__init_id(&throttle_event.header, &sample, event);
7232 ret = perf_output_begin(&handle, event,
7233 throttle_event.header.size);
7237 perf_output_put(&handle, throttle_event);
7238 perf_event__output_id_sample(event, &handle, &sample);
7239 perf_output_end(&handle);
7242 static void perf_log_itrace_start(struct perf_event *event)
7244 struct perf_output_handle handle;
7245 struct perf_sample_data sample;
7246 struct perf_aux_event {
7247 struct perf_event_header header;
7254 event = event->parent;
7256 if (!(event->pmu->capabilities & PERF_PMU_CAP_ITRACE) ||
7257 event->hw.itrace_started)
7260 rec.header.type = PERF_RECORD_ITRACE_START;
7261 rec.header.misc = 0;
7262 rec.header.size = sizeof(rec);
7263 rec.pid = perf_event_pid(event, current);
7264 rec.tid = perf_event_tid(event, current);
7266 perf_event_header__init_id(&rec.header, &sample, event);
7267 ret = perf_output_begin(&handle, event, rec.header.size);
7272 perf_output_put(&handle, rec);
7273 perf_event__output_id_sample(event, &handle, &sample);
7275 perf_output_end(&handle);
7279 __perf_event_account_interrupt(struct perf_event *event, int throttle)
7281 struct hw_perf_event *hwc = &event->hw;
7285 seq = __this_cpu_read(perf_throttled_seq);
7286 if (seq != hwc->interrupts_seq) {
7287 hwc->interrupts_seq = seq;
7288 hwc->interrupts = 1;
7291 if (unlikely(throttle
7292 && hwc->interrupts >= max_samples_per_tick)) {
7293 __this_cpu_inc(perf_throttled_count);
7294 tick_dep_set_cpu(smp_processor_id(), TICK_DEP_BIT_PERF_EVENTS);
7295 hwc->interrupts = MAX_INTERRUPTS;
7296 perf_log_throttle(event, 0);
7301 if (event->attr.freq) {
7302 u64 now = perf_clock();
7303 s64 delta = now - hwc->freq_time_stamp;
7305 hwc->freq_time_stamp = now;
7307 if (delta > 0 && delta < 2*TICK_NSEC)
7308 perf_adjust_period(event, delta, hwc->last_period, true);
7314 int perf_event_account_interrupt(struct perf_event *event)
7316 return __perf_event_account_interrupt(event, 1);
7320 * Generic event overflow handling, sampling.
7323 static int __perf_event_overflow(struct perf_event *event,
7324 int throttle, struct perf_sample_data *data,
7325 struct pt_regs *regs)
7327 int events = atomic_read(&event->event_limit);
7331 * Non-sampling counters might still use the PMI to fold short
7332 * hardware counters, ignore those.
7334 if (unlikely(!is_sampling_event(event)))
7337 ret = __perf_event_account_interrupt(event, throttle);
7340 * XXX event_limit might not quite work as expected on inherited
7344 event->pending_kill = POLL_IN;
7345 if (events && atomic_dec_and_test(&event->event_limit)) {
7347 event->pending_kill = POLL_HUP;
7349 perf_event_disable_inatomic(event);
7352 READ_ONCE(event->overflow_handler)(event, data, regs);
7354 if (*perf_event_fasync(event) && event->pending_kill) {
7355 event->pending_wakeup = 1;
7356 irq_work_queue(&event->pending);
7362 int perf_event_overflow(struct perf_event *event,
7363 struct perf_sample_data *data,
7364 struct pt_regs *regs)
7366 return __perf_event_overflow(event, 1, data, regs);
7370 * Generic software event infrastructure
7373 struct swevent_htable {
7374 struct swevent_hlist *swevent_hlist;
7375 struct mutex hlist_mutex;
7378 /* Recursion avoidance in each contexts */
7379 int recursion[PERF_NR_CONTEXTS];
7382 static DEFINE_PER_CPU(struct swevent_htable, swevent_htable);
7385 * We directly increment event->count and keep a second value in
7386 * event->hw.period_left to count intervals. This period event
7387 * is kept in the range [-sample_period, 0] so that we can use the
7391 u64 perf_swevent_set_period(struct perf_event *event)
7393 struct hw_perf_event *hwc = &event->hw;
7394 u64 period = hwc->last_period;
7398 hwc->last_period = hwc->sample_period;
7401 old = val = local64_read(&hwc->period_left);
7405 nr = div64_u64(period + val, period);
7406 offset = nr * period;
7408 if (local64_cmpxchg(&hwc->period_left, old, val) != old)
7414 static void perf_swevent_overflow(struct perf_event *event, u64 overflow,
7415 struct perf_sample_data *data,
7416 struct pt_regs *regs)
7418 struct hw_perf_event *hwc = &event->hw;
7422 overflow = perf_swevent_set_period(event);
7424 if (hwc->interrupts == MAX_INTERRUPTS)
7427 for (; overflow; overflow--) {
7428 if (__perf_event_overflow(event, throttle,
7431 * We inhibit the overflow from happening when
7432 * hwc->interrupts == MAX_INTERRUPTS.
7440 static void perf_swevent_event(struct perf_event *event, u64 nr,
7441 struct perf_sample_data *data,
7442 struct pt_regs *regs)
7444 struct hw_perf_event *hwc = &event->hw;
7446 local64_add(nr, &event->count);
7451 if (!is_sampling_event(event))
7454 if ((event->attr.sample_type & PERF_SAMPLE_PERIOD) && !event->attr.freq) {
7456 return perf_swevent_overflow(event, 1, data, regs);
7458 data->period = event->hw.last_period;
7460 if (nr == 1 && hwc->sample_period == 1 && !event->attr.freq)
7461 return perf_swevent_overflow(event, 1, data, regs);
7463 if (local64_add_negative(nr, &hwc->period_left))
7466 perf_swevent_overflow(event, 0, data, regs);
7469 static int perf_exclude_event(struct perf_event *event,
7470 struct pt_regs *regs)
7472 if (event->hw.state & PERF_HES_STOPPED)
7476 if (event->attr.exclude_user && user_mode(regs))
7479 if (event->attr.exclude_kernel && !user_mode(regs))
7486 static int perf_swevent_match(struct perf_event *event,
7487 enum perf_type_id type,
7489 struct perf_sample_data *data,
7490 struct pt_regs *regs)
7492 if (event->attr.type != type)
7495 if (event->attr.config != event_id)
7498 if (perf_exclude_event(event, regs))
7504 static inline u64 swevent_hash(u64 type, u32 event_id)
7506 u64 val = event_id | (type << 32);
7508 return hash_64(val, SWEVENT_HLIST_BITS);
7511 static inline struct hlist_head *
7512 __find_swevent_head(struct swevent_hlist *hlist, u64 type, u32 event_id)
7514 u64 hash = swevent_hash(type, event_id);
7516 return &hlist->heads[hash];
7519 /* For the read side: events when they trigger */
7520 static inline struct hlist_head *
7521 find_swevent_head_rcu(struct swevent_htable *swhash, u64 type, u32 event_id)
7523 struct swevent_hlist *hlist;
7525 hlist = rcu_dereference(swhash->swevent_hlist);
7529 return __find_swevent_head(hlist, type, event_id);
7532 /* For the event head insertion and removal in the hlist */
7533 static inline struct hlist_head *
7534 find_swevent_head(struct swevent_htable *swhash, struct perf_event *event)
7536 struct swevent_hlist *hlist;
7537 u32 event_id = event->attr.config;
7538 u64 type = event->attr.type;
7541 * Event scheduling is always serialized against hlist allocation
7542 * and release. Which makes the protected version suitable here.
7543 * The context lock guarantees that.
7545 hlist = rcu_dereference_protected(swhash->swevent_hlist,
7546 lockdep_is_held(&event->ctx->lock));
7550 return __find_swevent_head(hlist, type, event_id);
7553 static void do_perf_sw_event(enum perf_type_id type, u32 event_id,
7555 struct perf_sample_data *data,
7556 struct pt_regs *regs)
7558 struct swevent_htable *swhash = this_cpu_ptr(&swevent_htable);
7559 struct perf_event *event;
7560 struct hlist_head *head;
7563 head = find_swevent_head_rcu(swhash, type, event_id);
7567 hlist_for_each_entry_rcu(event, head, hlist_entry) {
7568 if (perf_swevent_match(event, type, event_id, data, regs))
7569 perf_swevent_event(event, nr, data, regs);
7575 DEFINE_PER_CPU(struct pt_regs, __perf_regs[4]);
7577 int perf_swevent_get_recursion_context(void)
7579 struct swevent_htable *swhash = this_cpu_ptr(&swevent_htable);
7581 return get_recursion_context(swhash->recursion);
7583 EXPORT_SYMBOL_GPL(perf_swevent_get_recursion_context);
7585 void perf_swevent_put_recursion_context(int rctx)
7587 struct swevent_htable *swhash = this_cpu_ptr(&swevent_htable);
7589 put_recursion_context(swhash->recursion, rctx);
7592 void ___perf_sw_event(u32 event_id, u64 nr, struct pt_regs *regs, u64 addr)
7594 struct perf_sample_data data;
7596 if (WARN_ON_ONCE(!regs))
7599 perf_sample_data_init(&data, addr, 0);
7600 do_perf_sw_event(PERF_TYPE_SOFTWARE, event_id, nr, &data, regs);
7603 void __perf_sw_event(u32 event_id, u64 nr, struct pt_regs *regs, u64 addr)
7607 preempt_disable_notrace();
7608 rctx = perf_swevent_get_recursion_context();
7609 if (unlikely(rctx < 0))
7612 ___perf_sw_event(event_id, nr, regs, addr);
7614 perf_swevent_put_recursion_context(rctx);
7616 preempt_enable_notrace();
7619 static void perf_swevent_read(struct perf_event *event)
7623 static int perf_swevent_add(struct perf_event *event, int flags)
7625 struct swevent_htable *swhash = this_cpu_ptr(&swevent_htable);
7626 struct hw_perf_event *hwc = &event->hw;
7627 struct hlist_head *head;
7629 if (is_sampling_event(event)) {
7630 hwc->last_period = hwc->sample_period;
7631 perf_swevent_set_period(event);
7634 hwc->state = !(flags & PERF_EF_START);
7636 head = find_swevent_head(swhash, event);
7637 if (WARN_ON_ONCE(!head))
7640 hlist_add_head_rcu(&event->hlist_entry, head);
7641 perf_event_update_userpage(event);
7646 static void perf_swevent_del(struct perf_event *event, int flags)
7648 hlist_del_rcu(&event->hlist_entry);
7651 static void perf_swevent_start(struct perf_event *event, int flags)
7653 event->hw.state = 0;
7656 static void perf_swevent_stop(struct perf_event *event, int flags)
7658 event->hw.state = PERF_HES_STOPPED;
7661 /* Deref the hlist from the update side */
7662 static inline struct swevent_hlist *
7663 swevent_hlist_deref(struct swevent_htable *swhash)
7665 return rcu_dereference_protected(swhash->swevent_hlist,
7666 lockdep_is_held(&swhash->hlist_mutex));
7669 static void swevent_hlist_release(struct swevent_htable *swhash)
7671 struct swevent_hlist *hlist = swevent_hlist_deref(swhash);
7676 RCU_INIT_POINTER(swhash->swevent_hlist, NULL);
7677 kfree_rcu(hlist, rcu_head);
7680 static void swevent_hlist_put_cpu(int cpu)
7682 struct swevent_htable *swhash = &per_cpu(swevent_htable, cpu);
7684 mutex_lock(&swhash->hlist_mutex);
7686 if (!--swhash->hlist_refcount)
7687 swevent_hlist_release(swhash);
7689 mutex_unlock(&swhash->hlist_mutex);
7692 static void swevent_hlist_put(void)
7696 for_each_possible_cpu(cpu)
7697 swevent_hlist_put_cpu(cpu);
7700 static int swevent_hlist_get_cpu(int cpu)
7702 struct swevent_htable *swhash = &per_cpu(swevent_htable, cpu);
7705 mutex_lock(&swhash->hlist_mutex);
7706 if (!swevent_hlist_deref(swhash) && cpu_online(cpu)) {
7707 struct swevent_hlist *hlist;
7709 hlist = kzalloc(sizeof(*hlist), GFP_KERNEL);
7714 rcu_assign_pointer(swhash->swevent_hlist, hlist);
7716 swhash->hlist_refcount++;
7718 mutex_unlock(&swhash->hlist_mutex);
7723 static int swevent_hlist_get(void)
7725 int err, cpu, failed_cpu;
7728 for_each_possible_cpu(cpu) {
7729 err = swevent_hlist_get_cpu(cpu);
7739 for_each_possible_cpu(cpu) {
7740 if (cpu == failed_cpu)
7742 swevent_hlist_put_cpu(cpu);
7749 struct static_key perf_swevent_enabled[PERF_COUNT_SW_MAX];
7751 static void sw_perf_event_destroy(struct perf_event *event)
7753 u64 event_id = event->attr.config;
7755 WARN_ON(event->parent);
7757 static_key_slow_dec(&perf_swevent_enabled[event_id]);
7758 swevent_hlist_put();
7761 static int perf_swevent_init(struct perf_event *event)
7763 u64 event_id = event->attr.config;
7765 if (event->attr.type != PERF_TYPE_SOFTWARE)
7769 * no branch sampling for software events
7771 if (has_branch_stack(event))
7775 case PERF_COUNT_SW_CPU_CLOCK:
7776 case PERF_COUNT_SW_TASK_CLOCK:
7783 if (event_id >= PERF_COUNT_SW_MAX)
7786 if (!event->parent) {
7789 err = swevent_hlist_get();
7793 static_key_slow_inc(&perf_swevent_enabled[event_id]);
7794 event->destroy = sw_perf_event_destroy;
7800 static struct pmu perf_swevent = {
7801 .task_ctx_nr = perf_sw_context,
7803 .capabilities = PERF_PMU_CAP_NO_NMI,
7805 .event_init = perf_swevent_init,
7806 .add = perf_swevent_add,
7807 .del = perf_swevent_del,
7808 .start = perf_swevent_start,
7809 .stop = perf_swevent_stop,
7810 .read = perf_swevent_read,
7813 #ifdef CONFIG_EVENT_TRACING
7815 static int perf_tp_filter_match(struct perf_event *event,
7816 struct perf_sample_data *data)
7818 void *record = data->raw->frag.data;
7820 /* only top level events have filters set */
7822 event = event->parent;
7824 if (likely(!event->filter) || filter_match_preds(event->filter, record))
7829 static int perf_tp_event_match(struct perf_event *event,
7830 struct perf_sample_data *data,
7831 struct pt_regs *regs)
7833 if (event->hw.state & PERF_HES_STOPPED)
7836 * All tracepoints are from kernel-space.
7838 if (event->attr.exclude_kernel)
7841 if (!perf_tp_filter_match(event, data))
7847 void perf_trace_run_bpf_submit(void *raw_data, int size, int rctx,
7848 struct trace_event_call *call, u64 count,
7849 struct pt_regs *regs, struct hlist_head *head,
7850 struct task_struct *task)
7852 struct bpf_prog *prog = call->prog;
7855 *(struct pt_regs **)raw_data = regs;
7856 if (!trace_call_bpf(prog, raw_data) || hlist_empty(head)) {
7857 perf_swevent_put_recursion_context(rctx);
7861 perf_tp_event(call->event.type, count, raw_data, size, regs, head,
7864 EXPORT_SYMBOL_GPL(perf_trace_run_bpf_submit);
7866 void perf_tp_event(u16 event_type, u64 count, void *record, int entry_size,
7867 struct pt_regs *regs, struct hlist_head *head, int rctx,
7868 struct task_struct *task)
7870 struct perf_sample_data data;
7871 struct perf_event *event;
7873 struct perf_raw_record raw = {
7880 perf_sample_data_init(&data, 0, 0);
7883 perf_trace_buf_update(record, event_type);
7885 hlist_for_each_entry_rcu(event, head, hlist_entry) {
7886 if (perf_tp_event_match(event, &data, regs))
7887 perf_swevent_event(event, count, &data, regs);
7891 * If we got specified a target task, also iterate its context and
7892 * deliver this event there too.
7894 if (task && task != current) {
7895 struct perf_event_context *ctx;
7896 struct trace_entry *entry = record;
7899 ctx = rcu_dereference(task->perf_event_ctxp[perf_sw_context]);
7903 list_for_each_entry_rcu(event, &ctx->event_list, event_entry) {
7904 if (event->attr.type != PERF_TYPE_TRACEPOINT)
7906 if (event->attr.config != entry->type)
7908 if (perf_tp_event_match(event, &data, regs))
7909 perf_swevent_event(event, count, &data, regs);
7915 perf_swevent_put_recursion_context(rctx);
7917 EXPORT_SYMBOL_GPL(perf_tp_event);
7919 static void tp_perf_event_destroy(struct perf_event *event)
7921 perf_trace_destroy(event);
7924 static int perf_tp_event_init(struct perf_event *event)
7928 if (event->attr.type != PERF_TYPE_TRACEPOINT)
7932 * no branch sampling for tracepoint events
7934 if (has_branch_stack(event))
7937 err = perf_trace_init(event);
7941 event->destroy = tp_perf_event_destroy;
7946 static struct pmu perf_tracepoint = {
7947 .task_ctx_nr = perf_sw_context,
7949 .event_init = perf_tp_event_init,
7950 .add = perf_trace_add,
7951 .del = perf_trace_del,
7952 .start = perf_swevent_start,
7953 .stop = perf_swevent_stop,
7954 .read = perf_swevent_read,
7957 static inline void perf_tp_register(void)
7959 perf_pmu_register(&perf_tracepoint, "tracepoint", PERF_TYPE_TRACEPOINT);
7962 static void perf_event_free_filter(struct perf_event *event)
7964 ftrace_profile_free_filter(event);
7967 #ifdef CONFIG_BPF_SYSCALL
7968 static void bpf_overflow_handler(struct perf_event *event,
7969 struct perf_sample_data *data,
7970 struct pt_regs *regs)
7972 struct bpf_perf_event_data_kern ctx = {
7979 if (unlikely(__this_cpu_inc_return(bpf_prog_active) != 1))
7982 ret = BPF_PROG_RUN(event->prog, &ctx);
7985 __this_cpu_dec(bpf_prog_active);
7990 event->orig_overflow_handler(event, data, regs);
7993 static int perf_event_set_bpf_handler(struct perf_event *event, u32 prog_fd)
7995 struct bpf_prog *prog;
7997 if (event->overflow_handler_context)
7998 /* hw breakpoint or kernel counter */
8004 prog = bpf_prog_get_type(prog_fd, BPF_PROG_TYPE_PERF_EVENT);
8006 return PTR_ERR(prog);
8009 event->orig_overflow_handler = READ_ONCE(event->overflow_handler);
8010 WRITE_ONCE(event->overflow_handler, bpf_overflow_handler);
8014 static void perf_event_free_bpf_handler(struct perf_event *event)
8016 struct bpf_prog *prog = event->prog;
8021 WRITE_ONCE(event->overflow_handler, event->orig_overflow_handler);
8026 static int perf_event_set_bpf_handler(struct perf_event *event, u32 prog_fd)
8030 static void perf_event_free_bpf_handler(struct perf_event *event)
8035 static int perf_event_set_bpf_prog(struct perf_event *event, u32 prog_fd)
8037 bool is_kprobe, is_tracepoint;
8038 struct bpf_prog *prog;
8040 if (event->attr.type == PERF_TYPE_HARDWARE ||
8041 event->attr.type == PERF_TYPE_SOFTWARE)
8042 return perf_event_set_bpf_handler(event, prog_fd);
8044 if (event->attr.type != PERF_TYPE_TRACEPOINT)
8047 if (event->tp_event->prog)
8050 is_kprobe = event->tp_event->flags & TRACE_EVENT_FL_UKPROBE;
8051 is_tracepoint = event->tp_event->flags & TRACE_EVENT_FL_TRACEPOINT;
8052 if (!is_kprobe && !is_tracepoint)
8053 /* bpf programs can only be attached to u/kprobe or tracepoint */
8056 prog = bpf_prog_get(prog_fd);
8058 return PTR_ERR(prog);
8060 if ((is_kprobe && prog->type != BPF_PROG_TYPE_KPROBE) ||
8061 (is_tracepoint && prog->type != BPF_PROG_TYPE_TRACEPOINT)) {
8062 /* valid fd, but invalid bpf program type */
8067 if (is_tracepoint) {
8068 int off = trace_event_get_offsets(event->tp_event);
8070 if (prog->aux->max_ctx_offset > off) {
8075 event->tp_event->prog = prog;
8080 static void perf_event_free_bpf_prog(struct perf_event *event)
8082 struct bpf_prog *prog;
8084 perf_event_free_bpf_handler(event);
8086 if (!event->tp_event)
8089 prog = event->tp_event->prog;
8091 event->tp_event->prog = NULL;
8098 static inline void perf_tp_register(void)
8102 static void perf_event_free_filter(struct perf_event *event)
8106 static int perf_event_set_bpf_prog(struct perf_event *event, u32 prog_fd)
8111 static void perf_event_free_bpf_prog(struct perf_event *event)
8114 #endif /* CONFIG_EVENT_TRACING */
8116 #ifdef CONFIG_HAVE_HW_BREAKPOINT
8117 void perf_bp_event(struct perf_event *bp, void *data)
8119 struct perf_sample_data sample;
8120 struct pt_regs *regs = data;
8122 perf_sample_data_init(&sample, bp->attr.bp_addr, 0);
8124 if (!bp->hw.state && !perf_exclude_event(bp, regs))
8125 perf_swevent_event(bp, 1, &sample, regs);
8130 * Allocate a new address filter
8132 static struct perf_addr_filter *
8133 perf_addr_filter_new(struct perf_event *event, struct list_head *filters)
8135 int node = cpu_to_node(event->cpu == -1 ? 0 : event->cpu);
8136 struct perf_addr_filter *filter;
8138 filter = kzalloc_node(sizeof(*filter), GFP_KERNEL, node);
8142 INIT_LIST_HEAD(&filter->entry);
8143 list_add_tail(&filter->entry, filters);
8148 static void free_filters_list(struct list_head *filters)
8150 struct perf_addr_filter *filter, *iter;
8152 list_for_each_entry_safe(filter, iter, filters, entry) {
8154 iput(filter->inode);
8155 list_del(&filter->entry);
8161 * Free existing address filters and optionally install new ones
8163 static void perf_addr_filters_splice(struct perf_event *event,
8164 struct list_head *head)
8166 unsigned long flags;
8169 if (!has_addr_filter(event))
8172 /* don't bother with children, they don't have their own filters */
8176 raw_spin_lock_irqsave(&event->addr_filters.lock, flags);
8178 list_splice_init(&event->addr_filters.list, &list);
8180 list_splice(head, &event->addr_filters.list);
8182 raw_spin_unlock_irqrestore(&event->addr_filters.lock, flags);
8184 free_filters_list(&list);
8188 * Scan through mm's vmas and see if one of them matches the
8189 * @filter; if so, adjust filter's address range.
8190 * Called with mm::mmap_sem down for reading.
8192 static unsigned long perf_addr_filter_apply(struct perf_addr_filter *filter,
8193 struct mm_struct *mm)
8195 struct vm_area_struct *vma;
8197 for (vma = mm->mmap; vma; vma = vma->vm_next) {
8198 struct file *file = vma->vm_file;
8199 unsigned long off = vma->vm_pgoff << PAGE_SHIFT;
8200 unsigned long vma_size = vma->vm_end - vma->vm_start;
8205 if (!perf_addr_filter_match(filter, file, off, vma_size))
8208 return vma->vm_start;
8215 * Update event's address range filters based on the
8216 * task's existing mappings, if any.
8218 static void perf_event_addr_filters_apply(struct perf_event *event)
8220 struct perf_addr_filters_head *ifh = perf_event_addr_filters(event);
8221 struct task_struct *task = READ_ONCE(event->ctx->task);
8222 struct perf_addr_filter *filter;
8223 struct mm_struct *mm = NULL;
8224 unsigned int count = 0;
8225 unsigned long flags;
8228 * We may observe TASK_TOMBSTONE, which means that the event tear-down
8229 * will stop on the parent's child_mutex that our caller is also holding
8231 if (task == TASK_TOMBSTONE)
8234 if (!ifh->nr_file_filters)
8237 mm = get_task_mm(event->ctx->task);
8241 down_read(&mm->mmap_sem);
8243 raw_spin_lock_irqsave(&ifh->lock, flags);
8244 list_for_each_entry(filter, &ifh->list, entry) {
8245 event->addr_filters_offs[count] = 0;
8248 * Adjust base offset if the filter is associated to a binary
8249 * that needs to be mapped:
8252 event->addr_filters_offs[count] =
8253 perf_addr_filter_apply(filter, mm);
8258 event->addr_filters_gen++;
8259 raw_spin_unlock_irqrestore(&ifh->lock, flags);
8261 up_read(&mm->mmap_sem);
8266 perf_event_stop(event, 1);
8270 * Address range filtering: limiting the data to certain
8271 * instruction address ranges. Filters are ioctl()ed to us from
8272 * userspace as ascii strings.
8274 * Filter string format:
8277 * where ACTION is one of the
8278 * * "filter": limit the trace to this region
8279 * * "start": start tracing from this address
8280 * * "stop": stop tracing at this address/region;
8282 * * for kernel addresses: <start address>[/<size>]
8283 * * for object files: <start address>[/<size>]@</path/to/object/file>
8285 * if <size> is not specified, the range is treated as a single address.
8299 IF_STATE_ACTION = 0,
8304 static const match_table_t if_tokens = {
8305 { IF_ACT_FILTER, "filter" },
8306 { IF_ACT_START, "start" },
8307 { IF_ACT_STOP, "stop" },
8308 { IF_SRC_FILE, "%u/%u@%s" },
8309 { IF_SRC_KERNEL, "%u/%u" },
8310 { IF_SRC_FILEADDR, "%u@%s" },
8311 { IF_SRC_KERNELADDR, "%u" },
8312 { IF_ACT_NONE, NULL },
8316 * Address filter string parser
8319 perf_event_parse_addr_filter(struct perf_event *event, char *fstr,
8320 struct list_head *filters)
8322 struct perf_addr_filter *filter = NULL;
8323 char *start, *orig, *filename = NULL;
8325 substring_t args[MAX_OPT_ARGS];
8326 int state = IF_STATE_ACTION, token;
8327 unsigned int kernel = 0;
8330 orig = fstr = kstrdup(fstr, GFP_KERNEL);
8334 while ((start = strsep(&fstr, " ,\n")) != NULL) {
8340 /* filter definition begins */
8341 if (state == IF_STATE_ACTION) {
8342 filter = perf_addr_filter_new(event, filters);
8347 token = match_token(start, if_tokens, args);
8354 if (state != IF_STATE_ACTION)
8357 state = IF_STATE_SOURCE;
8360 case IF_SRC_KERNELADDR:
8364 case IF_SRC_FILEADDR:
8366 if (state != IF_STATE_SOURCE)
8369 if (token == IF_SRC_FILE || token == IF_SRC_KERNEL)
8373 ret = kstrtoul(args[0].from, 0, &filter->offset);
8377 if (filter->range) {
8379 ret = kstrtoul(args[1].from, 0, &filter->size);
8384 if (token == IF_SRC_FILE || token == IF_SRC_FILEADDR) {
8385 int fpos = filter->range ? 2 : 1;
8387 filename = match_strdup(&args[fpos]);
8394 state = IF_STATE_END;
8402 * Filter definition is fully parsed, validate and install it.
8403 * Make sure that it doesn't contradict itself or the event's
8406 if (state == IF_STATE_END) {
8408 if (kernel && event->attr.exclude_kernel)
8416 * For now, we only support file-based filters
8417 * in per-task events; doing so for CPU-wide
8418 * events requires additional context switching
8419 * trickery, since same object code will be
8420 * mapped at different virtual addresses in
8421 * different processes.
8424 if (!event->ctx->task)
8425 goto fail_free_name;
8427 /* look up the path and grab its inode */
8428 ret = kern_path(filename, LOOKUP_FOLLOW, &path);
8430 goto fail_free_name;
8432 filter->inode = igrab(d_inode(path.dentry));
8438 if (!filter->inode ||
8439 !S_ISREG(filter->inode->i_mode))
8440 /* free_filters_list() will iput() */
8443 event->addr_filters.nr_file_filters++;
8446 /* ready to consume more filters */
8447 state = IF_STATE_ACTION;
8452 if (state != IF_STATE_ACTION)
8462 free_filters_list(filters);
8469 perf_event_set_addr_filter(struct perf_event *event, char *filter_str)
8475 * Since this is called in perf_ioctl() path, we're already holding
8478 lockdep_assert_held(&event->ctx->mutex);
8480 if (WARN_ON_ONCE(event->parent))
8483 ret = perf_event_parse_addr_filter(event, filter_str, &filters);
8485 goto fail_clear_files;
8487 ret = event->pmu->addr_filters_validate(&filters);
8489 goto fail_free_filters;
8491 /* remove existing filters, if any */
8492 perf_addr_filters_splice(event, &filters);
8494 /* install new filters */
8495 perf_event_for_each_child(event, perf_event_addr_filters_apply);
8500 free_filters_list(&filters);
8503 event->addr_filters.nr_file_filters = 0;
8508 static int perf_event_set_filter(struct perf_event *event, void __user *arg)
8513 if ((event->attr.type != PERF_TYPE_TRACEPOINT ||
8514 !IS_ENABLED(CONFIG_EVENT_TRACING)) &&
8515 !has_addr_filter(event))
8518 filter_str = strndup_user(arg, PAGE_SIZE);
8519 if (IS_ERR(filter_str))
8520 return PTR_ERR(filter_str);
8522 if (IS_ENABLED(CONFIG_EVENT_TRACING) &&
8523 event->attr.type == PERF_TYPE_TRACEPOINT)
8524 ret = ftrace_profile_set_filter(event, event->attr.config,
8526 else if (has_addr_filter(event))
8527 ret = perf_event_set_addr_filter(event, filter_str);
8534 * hrtimer based swevent callback
8537 static enum hrtimer_restart perf_swevent_hrtimer(struct hrtimer *hrtimer)
8539 enum hrtimer_restart ret = HRTIMER_RESTART;
8540 struct perf_sample_data data;
8541 struct pt_regs *regs;
8542 struct perf_event *event;
8545 event = container_of(hrtimer, struct perf_event, hw.hrtimer);
8547 if (event->state != PERF_EVENT_STATE_ACTIVE)
8548 return HRTIMER_NORESTART;
8550 event->pmu->read(event);
8552 perf_sample_data_init(&data, 0, event->hw.last_period);
8553 regs = get_irq_regs();
8555 if (regs && !perf_exclude_event(event, regs)) {
8556 if (!(event->attr.exclude_idle && is_idle_task(current)))
8557 if (__perf_event_overflow(event, 1, &data, regs))
8558 ret = HRTIMER_NORESTART;
8561 period = max_t(u64, 10000, event->hw.sample_period);
8562 hrtimer_forward_now(hrtimer, ns_to_ktime(period));
8567 static void perf_swevent_start_hrtimer(struct perf_event *event)
8569 struct hw_perf_event *hwc = &event->hw;
8572 if (!is_sampling_event(event))
8575 period = local64_read(&hwc->period_left);
8580 local64_set(&hwc->period_left, 0);
8582 period = max_t(u64, 10000, hwc->sample_period);
8584 hrtimer_start(&hwc->hrtimer, ns_to_ktime(period),
8585 HRTIMER_MODE_REL_PINNED);
8588 static void perf_swevent_cancel_hrtimer(struct perf_event *event)
8590 struct hw_perf_event *hwc = &event->hw;
8592 if (is_sampling_event(event)) {
8593 ktime_t remaining = hrtimer_get_remaining(&hwc->hrtimer);
8594 local64_set(&hwc->period_left, ktime_to_ns(remaining));
8596 hrtimer_cancel(&hwc->hrtimer);
8600 static void perf_swevent_init_hrtimer(struct perf_event *event)
8602 struct hw_perf_event *hwc = &event->hw;
8604 if (!is_sampling_event(event))
8607 hrtimer_init(&hwc->hrtimer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
8608 hwc->hrtimer.function = perf_swevent_hrtimer;
8611 * Since hrtimers have a fixed rate, we can do a static freq->period
8612 * mapping and avoid the whole period adjust feedback stuff.
8614 if (event->attr.freq) {
8615 long freq = event->attr.sample_freq;
8617 event->attr.sample_period = NSEC_PER_SEC / freq;
8618 hwc->sample_period = event->attr.sample_period;
8619 local64_set(&hwc->period_left, hwc->sample_period);
8620 hwc->last_period = hwc->sample_period;
8621 event->attr.freq = 0;
8626 * Software event: cpu wall time clock
8629 static void cpu_clock_event_update(struct perf_event *event)
8634 now = local_clock();
8635 prev = local64_xchg(&event->hw.prev_count, now);
8636 local64_add(now - prev, &event->count);
8639 static void cpu_clock_event_start(struct perf_event *event, int flags)
8641 local64_set(&event->hw.prev_count, local_clock());
8642 perf_swevent_start_hrtimer(event);
8645 static void cpu_clock_event_stop(struct perf_event *event, int flags)
8647 perf_swevent_cancel_hrtimer(event);
8648 cpu_clock_event_update(event);
8651 static int cpu_clock_event_add(struct perf_event *event, int flags)
8653 if (flags & PERF_EF_START)
8654 cpu_clock_event_start(event, flags);
8655 perf_event_update_userpage(event);
8660 static void cpu_clock_event_del(struct perf_event *event, int flags)
8662 cpu_clock_event_stop(event, flags);
8665 static void cpu_clock_event_read(struct perf_event *event)
8667 cpu_clock_event_update(event);
8670 static int cpu_clock_event_init(struct perf_event *event)
8672 if (event->attr.type != PERF_TYPE_SOFTWARE)
8675 if (event->attr.config != PERF_COUNT_SW_CPU_CLOCK)
8679 * no branch sampling for software events
8681 if (has_branch_stack(event))
8684 perf_swevent_init_hrtimer(event);
8689 static struct pmu perf_cpu_clock = {
8690 .task_ctx_nr = perf_sw_context,
8692 .capabilities = PERF_PMU_CAP_NO_NMI,
8694 .event_init = cpu_clock_event_init,
8695 .add = cpu_clock_event_add,
8696 .del = cpu_clock_event_del,
8697 .start = cpu_clock_event_start,
8698 .stop = cpu_clock_event_stop,
8699 .read = cpu_clock_event_read,
8703 * Software event: task time clock
8706 static void task_clock_event_update(struct perf_event *event, u64 now)
8711 prev = local64_xchg(&event->hw.prev_count, now);
8713 local64_add(delta, &event->count);
8716 static void task_clock_event_start(struct perf_event *event, int flags)
8718 local64_set(&event->hw.prev_count, event->ctx->time);
8719 perf_swevent_start_hrtimer(event);
8722 static void task_clock_event_stop(struct perf_event *event, int flags)
8724 perf_swevent_cancel_hrtimer(event);
8725 task_clock_event_update(event, event->ctx->time);
8728 static int task_clock_event_add(struct perf_event *event, int flags)
8730 if (flags & PERF_EF_START)
8731 task_clock_event_start(event, flags);
8732 perf_event_update_userpage(event);
8737 static void task_clock_event_del(struct perf_event *event, int flags)
8739 task_clock_event_stop(event, PERF_EF_UPDATE);
8742 static void task_clock_event_read(struct perf_event *event)
8744 u64 now = perf_clock();
8745 u64 delta = now - event->ctx->timestamp;
8746 u64 time = event->ctx->time + delta;
8748 task_clock_event_update(event, time);
8751 static int task_clock_event_init(struct perf_event *event)
8753 if (event->attr.type != PERF_TYPE_SOFTWARE)
8756 if (event->attr.config != PERF_COUNT_SW_TASK_CLOCK)
8760 * no branch sampling for software events
8762 if (has_branch_stack(event))
8765 perf_swevent_init_hrtimer(event);
8770 static struct pmu perf_task_clock = {
8771 .task_ctx_nr = perf_sw_context,
8773 .capabilities = PERF_PMU_CAP_NO_NMI,
8775 .event_init = task_clock_event_init,
8776 .add = task_clock_event_add,
8777 .del = task_clock_event_del,
8778 .start = task_clock_event_start,
8779 .stop = task_clock_event_stop,
8780 .read = task_clock_event_read,
8783 static void perf_pmu_nop_void(struct pmu *pmu)
8787 static void perf_pmu_nop_txn(struct pmu *pmu, unsigned int flags)
8791 static int perf_pmu_nop_int(struct pmu *pmu)
8796 static DEFINE_PER_CPU(unsigned int, nop_txn_flags);
8798 static void perf_pmu_start_txn(struct pmu *pmu, unsigned int flags)
8800 __this_cpu_write(nop_txn_flags, flags);
8802 if (flags & ~PERF_PMU_TXN_ADD)
8805 perf_pmu_disable(pmu);
8808 static int perf_pmu_commit_txn(struct pmu *pmu)
8810 unsigned int flags = __this_cpu_read(nop_txn_flags);
8812 __this_cpu_write(nop_txn_flags, 0);
8814 if (flags & ~PERF_PMU_TXN_ADD)
8817 perf_pmu_enable(pmu);
8821 static void perf_pmu_cancel_txn(struct pmu *pmu)
8823 unsigned int flags = __this_cpu_read(nop_txn_flags);
8825 __this_cpu_write(nop_txn_flags, 0);
8827 if (flags & ~PERF_PMU_TXN_ADD)
8830 perf_pmu_enable(pmu);
8833 static int perf_event_idx_default(struct perf_event *event)
8839 * Ensures all contexts with the same task_ctx_nr have the same
8840 * pmu_cpu_context too.
8842 static struct perf_cpu_context __percpu *find_pmu_context(int ctxn)
8849 list_for_each_entry(pmu, &pmus, entry) {
8850 if (pmu->task_ctx_nr == ctxn)
8851 return pmu->pmu_cpu_context;
8857 static void free_pmu_context(struct pmu *pmu)
8859 mutex_lock(&pmus_lock);
8860 free_percpu(pmu->pmu_cpu_context);
8861 mutex_unlock(&pmus_lock);
8865 * Let userspace know that this PMU supports address range filtering:
8867 static ssize_t nr_addr_filters_show(struct device *dev,
8868 struct device_attribute *attr,
8871 struct pmu *pmu = dev_get_drvdata(dev);
8873 return snprintf(page, PAGE_SIZE - 1, "%d\n", pmu->nr_addr_filters);
8875 DEVICE_ATTR_RO(nr_addr_filters);
8877 static struct idr pmu_idr;
8880 type_show(struct device *dev, struct device_attribute *attr, char *page)
8882 struct pmu *pmu = dev_get_drvdata(dev);
8884 return snprintf(page, PAGE_SIZE-1, "%d\n", pmu->type);
8886 static DEVICE_ATTR_RO(type);
8889 perf_event_mux_interval_ms_show(struct device *dev,
8890 struct device_attribute *attr,
8893 struct pmu *pmu = dev_get_drvdata(dev);
8895 return snprintf(page, PAGE_SIZE-1, "%d\n", pmu->hrtimer_interval_ms);
8898 static DEFINE_MUTEX(mux_interval_mutex);
8901 perf_event_mux_interval_ms_store(struct device *dev,
8902 struct device_attribute *attr,
8903 const char *buf, size_t count)
8905 struct pmu *pmu = dev_get_drvdata(dev);
8906 int timer, cpu, ret;
8908 ret = kstrtoint(buf, 0, &timer);
8915 /* same value, noting to do */
8916 if (timer == pmu->hrtimer_interval_ms)
8919 mutex_lock(&mux_interval_mutex);
8920 pmu->hrtimer_interval_ms = timer;
8922 /* update all cpuctx for this PMU */
8924 for_each_online_cpu(cpu) {
8925 struct perf_cpu_context *cpuctx;
8926 cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
8927 cpuctx->hrtimer_interval = ns_to_ktime(NSEC_PER_MSEC * timer);
8929 cpu_function_call(cpu,
8930 (remote_function_f)perf_mux_hrtimer_restart, cpuctx);
8933 mutex_unlock(&mux_interval_mutex);
8937 static DEVICE_ATTR_RW(perf_event_mux_interval_ms);
8939 static struct attribute *pmu_dev_attrs[] = {
8940 &dev_attr_type.attr,
8941 &dev_attr_perf_event_mux_interval_ms.attr,
8944 ATTRIBUTE_GROUPS(pmu_dev);
8946 static int pmu_bus_running;
8947 static struct bus_type pmu_bus = {
8948 .name = "event_source",
8949 .dev_groups = pmu_dev_groups,
8952 static void pmu_dev_release(struct device *dev)
8957 static int pmu_dev_alloc(struct pmu *pmu)
8961 pmu->dev = kzalloc(sizeof(struct device), GFP_KERNEL);
8965 pmu->dev->groups = pmu->attr_groups;
8966 device_initialize(pmu->dev);
8967 ret = dev_set_name(pmu->dev, "%s", pmu->name);
8971 dev_set_drvdata(pmu->dev, pmu);
8972 pmu->dev->bus = &pmu_bus;
8973 pmu->dev->release = pmu_dev_release;
8974 ret = device_add(pmu->dev);
8978 /* For PMUs with address filters, throw in an extra attribute: */
8979 if (pmu->nr_addr_filters)
8980 ret = device_create_file(pmu->dev, &dev_attr_nr_addr_filters);
8989 device_del(pmu->dev);
8992 put_device(pmu->dev);
8996 static struct lock_class_key cpuctx_mutex;
8997 static struct lock_class_key cpuctx_lock;
8999 int perf_pmu_register(struct pmu *pmu, const char *name, int type)
9003 mutex_lock(&pmus_lock);
9005 pmu->pmu_disable_count = alloc_percpu(int);
9006 if (!pmu->pmu_disable_count)
9015 type = idr_alloc(&pmu_idr, pmu, PERF_TYPE_MAX, 0, GFP_KERNEL);
9023 if (pmu_bus_running) {
9024 ret = pmu_dev_alloc(pmu);
9030 if (pmu->task_ctx_nr == perf_hw_context) {
9031 static int hw_context_taken = 0;
9034 * Other than systems with heterogeneous CPUs, it never makes
9035 * sense for two PMUs to share perf_hw_context. PMUs which are
9036 * uncore must use perf_invalid_context.
9038 if (WARN_ON_ONCE(hw_context_taken &&
9039 !(pmu->capabilities & PERF_PMU_CAP_HETEROGENEOUS_CPUS)))
9040 pmu->task_ctx_nr = perf_invalid_context;
9042 hw_context_taken = 1;
9045 pmu->pmu_cpu_context = find_pmu_context(pmu->task_ctx_nr);
9046 if (pmu->pmu_cpu_context)
9047 goto got_cpu_context;
9050 pmu->pmu_cpu_context = alloc_percpu(struct perf_cpu_context);
9051 if (!pmu->pmu_cpu_context)
9054 for_each_possible_cpu(cpu) {
9055 struct perf_cpu_context *cpuctx;
9057 cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
9058 __perf_event_init_context(&cpuctx->ctx);
9059 lockdep_set_class(&cpuctx->ctx.mutex, &cpuctx_mutex);
9060 lockdep_set_class(&cpuctx->ctx.lock, &cpuctx_lock);
9061 cpuctx->ctx.pmu = pmu;
9063 __perf_mux_hrtimer_init(cpuctx, cpu);
9067 if (!pmu->start_txn) {
9068 if (pmu->pmu_enable) {
9070 * If we have pmu_enable/pmu_disable calls, install
9071 * transaction stubs that use that to try and batch
9072 * hardware accesses.
9074 pmu->start_txn = perf_pmu_start_txn;
9075 pmu->commit_txn = perf_pmu_commit_txn;
9076 pmu->cancel_txn = perf_pmu_cancel_txn;
9078 pmu->start_txn = perf_pmu_nop_txn;
9079 pmu->commit_txn = perf_pmu_nop_int;
9080 pmu->cancel_txn = perf_pmu_nop_void;
9084 if (!pmu->pmu_enable) {
9085 pmu->pmu_enable = perf_pmu_nop_void;
9086 pmu->pmu_disable = perf_pmu_nop_void;
9089 if (!pmu->event_idx)
9090 pmu->event_idx = perf_event_idx_default;
9092 list_add_rcu(&pmu->entry, &pmus);
9093 atomic_set(&pmu->exclusive_cnt, 0);
9096 mutex_unlock(&pmus_lock);
9101 device_del(pmu->dev);
9102 put_device(pmu->dev);
9105 if (pmu->type >= PERF_TYPE_MAX)
9106 idr_remove(&pmu_idr, pmu->type);
9109 free_percpu(pmu->pmu_disable_count);
9112 EXPORT_SYMBOL_GPL(perf_pmu_register);
9114 void perf_pmu_unregister(struct pmu *pmu)
9118 mutex_lock(&pmus_lock);
9119 remove_device = pmu_bus_running;
9120 list_del_rcu(&pmu->entry);
9121 mutex_unlock(&pmus_lock);
9124 * We dereference the pmu list under both SRCU and regular RCU, so
9125 * synchronize against both of those.
9127 synchronize_srcu(&pmus_srcu);
9130 free_percpu(pmu->pmu_disable_count);
9131 if (pmu->type >= PERF_TYPE_MAX)
9132 idr_remove(&pmu_idr, pmu->type);
9133 if (remove_device) {
9134 if (pmu->nr_addr_filters)
9135 device_remove_file(pmu->dev, &dev_attr_nr_addr_filters);
9136 device_del(pmu->dev);
9137 put_device(pmu->dev);
9139 free_pmu_context(pmu);
9141 EXPORT_SYMBOL_GPL(perf_pmu_unregister);
9143 static int perf_try_init_event(struct pmu *pmu, struct perf_event *event)
9145 struct perf_event_context *ctx = NULL;
9148 if (!try_module_get(pmu->module))
9151 if (event->group_leader != event) {
9153 * This ctx->mutex can nest when we're called through
9154 * inheritance. See the perf_event_ctx_lock_nested() comment.
9156 ctx = perf_event_ctx_lock_nested(event->group_leader,
9157 SINGLE_DEPTH_NESTING);
9162 ret = pmu->event_init(event);
9165 perf_event_ctx_unlock(event->group_leader, ctx);
9168 module_put(pmu->module);
9173 static struct pmu *perf_init_event(struct perf_event *event)
9175 struct pmu *pmu = NULL;
9179 idx = srcu_read_lock(&pmus_srcu);
9181 /* Try parent's PMU first: */
9182 if (event->parent && event->parent->pmu) {
9183 pmu = event->parent->pmu;
9184 ret = perf_try_init_event(pmu, event);
9190 pmu = idr_find(&pmu_idr, event->attr.type);
9193 ret = perf_try_init_event(pmu, event);
9199 list_for_each_entry_rcu(pmu, &pmus, entry) {
9200 ret = perf_try_init_event(pmu, event);
9204 if (ret != -ENOENT) {
9209 pmu = ERR_PTR(-ENOENT);
9211 srcu_read_unlock(&pmus_srcu, idx);
9216 static void attach_sb_event(struct perf_event *event)
9218 struct pmu_event_list *pel = per_cpu_ptr(&pmu_sb_events, event->cpu);
9220 raw_spin_lock(&pel->lock);
9221 list_add_rcu(&event->sb_list, &pel->list);
9222 raw_spin_unlock(&pel->lock);
9226 * We keep a list of all !task (and therefore per-cpu) events
9227 * that need to receive side-band records.
9229 * This avoids having to scan all the various PMU per-cpu contexts
9232 static void account_pmu_sb_event(struct perf_event *event)
9234 if (is_sb_event(event))
9235 attach_sb_event(event);
9238 static void account_event_cpu(struct perf_event *event, int cpu)
9243 if (is_cgroup_event(event))
9244 atomic_inc(&per_cpu(perf_cgroup_events, cpu));
9247 /* Freq events need the tick to stay alive (see perf_event_task_tick). */
9248 static void account_freq_event_nohz(void)
9250 #ifdef CONFIG_NO_HZ_FULL
9251 /* Lock so we don't race with concurrent unaccount */
9252 spin_lock(&nr_freq_lock);
9253 if (atomic_inc_return(&nr_freq_events) == 1)
9254 tick_nohz_dep_set(TICK_DEP_BIT_PERF_EVENTS);
9255 spin_unlock(&nr_freq_lock);
9259 static void account_freq_event(void)
9261 if (tick_nohz_full_enabled())
9262 account_freq_event_nohz();
9264 atomic_inc(&nr_freq_events);
9268 static void account_event(struct perf_event *event)
9275 if (event->attach_state & PERF_ATTACH_TASK)
9277 if (event->attr.mmap || event->attr.mmap_data)
9278 atomic_inc(&nr_mmap_events);
9279 if (event->attr.comm)
9280 atomic_inc(&nr_comm_events);
9281 if (event->attr.namespaces)
9282 atomic_inc(&nr_namespaces_events);
9283 if (event->attr.task)
9284 atomic_inc(&nr_task_events);
9285 if (event->attr.freq)
9286 account_freq_event();
9287 if (event->attr.context_switch) {
9288 atomic_inc(&nr_switch_events);
9291 if (has_branch_stack(event))
9293 if (is_cgroup_event(event))
9297 if (atomic_inc_not_zero(&perf_sched_count))
9300 mutex_lock(&perf_sched_mutex);
9301 if (!atomic_read(&perf_sched_count)) {
9302 static_branch_enable(&perf_sched_events);
9304 * Guarantee that all CPUs observe they key change and
9305 * call the perf scheduling hooks before proceeding to
9306 * install events that need them.
9308 synchronize_sched();
9311 * Now that we have waited for the sync_sched(), allow further
9312 * increments to by-pass the mutex.
9314 atomic_inc(&perf_sched_count);
9315 mutex_unlock(&perf_sched_mutex);
9319 account_event_cpu(event, event->cpu);
9321 account_pmu_sb_event(event);
9325 * Allocate and initialize a event structure
9327 static struct perf_event *
9328 perf_event_alloc(struct perf_event_attr *attr, int cpu,
9329 struct task_struct *task,
9330 struct perf_event *group_leader,
9331 struct perf_event *parent_event,
9332 perf_overflow_handler_t overflow_handler,
9333 void *context, int cgroup_fd)
9336 struct perf_event *event;
9337 struct hw_perf_event *hwc;
9340 if ((unsigned)cpu >= nr_cpu_ids) {
9341 if (!task || cpu != -1)
9342 return ERR_PTR(-EINVAL);
9345 event = kzalloc(sizeof(*event), GFP_KERNEL);
9347 return ERR_PTR(-ENOMEM);
9350 * Single events are their own group leaders, with an
9351 * empty sibling list:
9354 group_leader = event;
9356 mutex_init(&event->child_mutex);
9357 INIT_LIST_HEAD(&event->child_list);
9359 INIT_LIST_HEAD(&event->group_entry);
9360 INIT_LIST_HEAD(&event->event_entry);
9361 INIT_LIST_HEAD(&event->sibling_list);
9362 INIT_LIST_HEAD(&event->rb_entry);
9363 INIT_LIST_HEAD(&event->active_entry);
9364 INIT_LIST_HEAD(&event->addr_filters.list);
9365 INIT_HLIST_NODE(&event->hlist_entry);
9368 init_waitqueue_head(&event->waitq);
9369 init_irq_work(&event->pending, perf_pending_event);
9371 mutex_init(&event->mmap_mutex);
9372 raw_spin_lock_init(&event->addr_filters.lock);
9374 atomic_long_set(&event->refcount, 1);
9376 event->attr = *attr;
9377 event->group_leader = group_leader;
9381 event->parent = parent_event;
9383 event->ns = get_pid_ns(task_active_pid_ns(current));
9384 event->id = atomic64_inc_return(&perf_event_id);
9386 event->state = PERF_EVENT_STATE_INACTIVE;
9389 event->attach_state = PERF_ATTACH_TASK;
9391 * XXX pmu::event_init needs to know what task to account to
9392 * and we cannot use the ctx information because we need the
9393 * pmu before we get a ctx.
9395 event->hw.target = task;
9398 event->clock = &local_clock;
9400 event->clock = parent_event->clock;
9402 if (!overflow_handler && parent_event) {
9403 overflow_handler = parent_event->overflow_handler;
9404 context = parent_event->overflow_handler_context;
9405 #if defined(CONFIG_BPF_SYSCALL) && defined(CONFIG_EVENT_TRACING)
9406 if (overflow_handler == bpf_overflow_handler) {
9407 struct bpf_prog *prog = bpf_prog_inc(parent_event->prog);
9410 err = PTR_ERR(prog);
9414 event->orig_overflow_handler =
9415 parent_event->orig_overflow_handler;
9420 if (overflow_handler) {
9421 event->overflow_handler = overflow_handler;
9422 event->overflow_handler_context = context;
9423 } else if (is_write_backward(event)){
9424 event->overflow_handler = perf_event_output_backward;
9425 event->overflow_handler_context = NULL;
9427 event->overflow_handler = perf_event_output_forward;
9428 event->overflow_handler_context = NULL;
9431 perf_event__state_init(event);
9436 hwc->sample_period = attr->sample_period;
9437 if (attr->freq && attr->sample_freq)
9438 hwc->sample_period = 1;
9439 hwc->last_period = hwc->sample_period;
9441 local64_set(&hwc->period_left, hwc->sample_period);
9444 * we currently do not support PERF_FORMAT_GROUP on inherited events
9446 if (attr->inherit && (attr->read_format & PERF_FORMAT_GROUP))
9449 if (!has_branch_stack(event))
9450 event->attr.branch_sample_type = 0;
9452 if (cgroup_fd != -1) {
9453 err = perf_cgroup_connect(cgroup_fd, event, attr, group_leader);
9458 pmu = perf_init_event(event);
9461 else if (IS_ERR(pmu)) {
9466 err = exclusive_event_init(event);
9470 if (has_addr_filter(event)) {
9471 event->addr_filters_offs = kcalloc(pmu->nr_addr_filters,
9472 sizeof(unsigned long),
9474 if (!event->addr_filters_offs)
9477 /* force hw sync on the address filters */
9478 event->addr_filters_gen = 1;
9481 if (!event->parent) {
9482 if (event->attr.sample_type & PERF_SAMPLE_CALLCHAIN) {
9483 err = get_callchain_buffers(attr->sample_max_stack);
9485 goto err_addr_filters;
9489 /* symmetric to unaccount_event() in _free_event() */
9490 account_event(event);
9495 kfree(event->addr_filters_offs);
9498 exclusive_event_destroy(event);
9502 event->destroy(event);
9503 module_put(pmu->module);
9505 if (is_cgroup_event(event))
9506 perf_detach_cgroup(event);
9508 put_pid_ns(event->ns);
9511 return ERR_PTR(err);
9514 static int perf_copy_attr(struct perf_event_attr __user *uattr,
9515 struct perf_event_attr *attr)
9520 if (!access_ok(VERIFY_WRITE, uattr, PERF_ATTR_SIZE_VER0))
9524 * zero the full structure, so that a short copy will be nice.
9526 memset(attr, 0, sizeof(*attr));
9528 ret = get_user(size, &uattr->size);
9532 if (size > PAGE_SIZE) /* silly large */
9535 if (!size) /* abi compat */
9536 size = PERF_ATTR_SIZE_VER0;
9538 if (size < PERF_ATTR_SIZE_VER0)
9542 * If we're handed a bigger struct than we know of,
9543 * ensure all the unknown bits are 0 - i.e. new
9544 * user-space does not rely on any kernel feature
9545 * extensions we dont know about yet.
9547 if (size > sizeof(*attr)) {
9548 unsigned char __user *addr;
9549 unsigned char __user *end;
9552 addr = (void __user *)uattr + sizeof(*attr);
9553 end = (void __user *)uattr + size;
9555 for (; addr < end; addr++) {
9556 ret = get_user(val, addr);
9562 size = sizeof(*attr);
9565 ret = copy_from_user(attr, uattr, size);
9569 if (attr->__reserved_1)
9572 if (attr->sample_type & ~(PERF_SAMPLE_MAX-1))
9575 if (attr->read_format & ~(PERF_FORMAT_MAX-1))
9578 if (attr->sample_type & PERF_SAMPLE_BRANCH_STACK) {
9579 u64 mask = attr->branch_sample_type;
9581 /* only using defined bits */
9582 if (mask & ~(PERF_SAMPLE_BRANCH_MAX-1))
9585 /* at least one branch bit must be set */
9586 if (!(mask & ~PERF_SAMPLE_BRANCH_PLM_ALL))
9589 /* propagate priv level, when not set for branch */
9590 if (!(mask & PERF_SAMPLE_BRANCH_PLM_ALL)) {
9592 /* exclude_kernel checked on syscall entry */
9593 if (!attr->exclude_kernel)
9594 mask |= PERF_SAMPLE_BRANCH_KERNEL;
9596 if (!attr->exclude_user)
9597 mask |= PERF_SAMPLE_BRANCH_USER;
9599 if (!attr->exclude_hv)
9600 mask |= PERF_SAMPLE_BRANCH_HV;
9602 * adjust user setting (for HW filter setup)
9604 attr->branch_sample_type = mask;
9606 /* privileged levels capture (kernel, hv): check permissions */
9607 if ((mask & PERF_SAMPLE_BRANCH_PERM_PLM)
9608 && perf_paranoid_kernel() && !capable(CAP_SYS_ADMIN))
9612 if (attr->sample_type & PERF_SAMPLE_REGS_USER) {
9613 ret = perf_reg_validate(attr->sample_regs_user);
9618 if (attr->sample_type & PERF_SAMPLE_STACK_USER) {
9619 if (!arch_perf_have_user_stack_dump())
9623 * We have __u32 type for the size, but so far
9624 * we can only use __u16 as maximum due to the
9625 * __u16 sample size limit.
9627 if (attr->sample_stack_user >= USHRT_MAX)
9629 else if (!IS_ALIGNED(attr->sample_stack_user, sizeof(u64)))
9633 if (attr->sample_type & PERF_SAMPLE_REGS_INTR)
9634 ret = perf_reg_validate(attr->sample_regs_intr);
9639 put_user(sizeof(*attr), &uattr->size);
9645 perf_event_set_output(struct perf_event *event, struct perf_event *output_event)
9647 struct ring_buffer *rb = NULL;
9653 /* don't allow circular references */
9654 if (event == output_event)
9658 * Don't allow cross-cpu buffers
9660 if (output_event->cpu != event->cpu)
9664 * If its not a per-cpu rb, it must be the same task.
9666 if (output_event->cpu == -1 && output_event->ctx != event->ctx)
9670 * Mixing clocks in the same buffer is trouble you don't need.
9672 if (output_event->clock != event->clock)
9676 * Either writing ring buffer from beginning or from end.
9677 * Mixing is not allowed.
9679 if (is_write_backward(output_event) != is_write_backward(event))
9683 * If both events generate aux data, they must be on the same PMU
9685 if (has_aux(event) && has_aux(output_event) &&
9686 event->pmu != output_event->pmu)
9690 mutex_lock(&event->mmap_mutex);
9691 /* Can't redirect output if we've got an active mmap() */
9692 if (atomic_read(&event->mmap_count))
9696 /* get the rb we want to redirect to */
9697 rb = ring_buffer_get(output_event);
9702 ring_buffer_attach(event, rb);
9706 mutex_unlock(&event->mmap_mutex);
9712 static void mutex_lock_double(struct mutex *a, struct mutex *b)
9718 mutex_lock_nested(b, SINGLE_DEPTH_NESTING);
9721 static int perf_event_set_clock(struct perf_event *event, clockid_t clk_id)
9723 bool nmi_safe = false;
9726 case CLOCK_MONOTONIC:
9727 event->clock = &ktime_get_mono_fast_ns;
9731 case CLOCK_MONOTONIC_RAW:
9732 event->clock = &ktime_get_raw_fast_ns;
9736 case CLOCK_REALTIME:
9737 event->clock = &ktime_get_real_ns;
9740 case CLOCK_BOOTTIME:
9741 event->clock = &ktime_get_boot_ns;
9745 event->clock = &ktime_get_tai_ns;
9752 if (!nmi_safe && !(event->pmu->capabilities & PERF_PMU_CAP_NO_NMI))
9759 * Variation on perf_event_ctx_lock_nested(), except we take two context
9762 static struct perf_event_context *
9763 __perf_event_ctx_lock_double(struct perf_event *group_leader,
9764 struct perf_event_context *ctx)
9766 struct perf_event_context *gctx;
9770 gctx = READ_ONCE(group_leader->ctx);
9771 if (!atomic_inc_not_zero(&gctx->refcount)) {
9777 mutex_lock_double(&gctx->mutex, &ctx->mutex);
9779 if (group_leader->ctx != gctx) {
9780 mutex_unlock(&ctx->mutex);
9781 mutex_unlock(&gctx->mutex);
9790 * sys_perf_event_open - open a performance event, associate it to a task/cpu
9792 * @attr_uptr: event_id type attributes for monitoring/sampling
9795 * @group_fd: group leader event fd
9797 SYSCALL_DEFINE5(perf_event_open,
9798 struct perf_event_attr __user *, attr_uptr,
9799 pid_t, pid, int, cpu, int, group_fd, unsigned long, flags)
9801 struct perf_event *group_leader = NULL, *output_event = NULL;
9802 struct perf_event *event, *sibling;
9803 struct perf_event_attr attr;
9804 struct perf_event_context *ctx, *uninitialized_var(gctx);
9805 struct file *event_file = NULL;
9806 struct fd group = {NULL, 0};
9807 struct task_struct *task = NULL;
9812 int f_flags = O_RDWR;
9815 /* for future expandability... */
9816 if (flags & ~PERF_FLAG_ALL)
9819 err = perf_copy_attr(attr_uptr, &attr);
9823 if (!attr.exclude_kernel) {
9824 if (perf_paranoid_kernel() && !capable(CAP_SYS_ADMIN))
9828 if (attr.namespaces) {
9829 if (!capable(CAP_SYS_ADMIN))
9834 if (attr.sample_freq > sysctl_perf_event_sample_rate)
9837 if (attr.sample_period & (1ULL << 63))
9841 if (!attr.sample_max_stack)
9842 attr.sample_max_stack = sysctl_perf_event_max_stack;
9845 * In cgroup mode, the pid argument is used to pass the fd
9846 * opened to the cgroup directory in cgroupfs. The cpu argument
9847 * designates the cpu on which to monitor threads from that
9850 if ((flags & PERF_FLAG_PID_CGROUP) && (pid == -1 || cpu == -1))
9853 if (flags & PERF_FLAG_FD_CLOEXEC)
9854 f_flags |= O_CLOEXEC;
9856 event_fd = get_unused_fd_flags(f_flags);
9860 if (group_fd != -1) {
9861 err = perf_fget_light(group_fd, &group);
9864 group_leader = group.file->private_data;
9865 if (flags & PERF_FLAG_FD_OUTPUT)
9866 output_event = group_leader;
9867 if (flags & PERF_FLAG_FD_NO_GROUP)
9868 group_leader = NULL;
9871 if (pid != -1 && !(flags & PERF_FLAG_PID_CGROUP)) {
9872 task = find_lively_task_by_vpid(pid);
9874 err = PTR_ERR(task);
9879 if (task && group_leader &&
9880 group_leader->attr.inherit != attr.inherit) {
9888 err = mutex_lock_interruptible(&task->signal->cred_guard_mutex);
9893 * Reuse ptrace permission checks for now.
9895 * We must hold cred_guard_mutex across this and any potential
9896 * perf_install_in_context() call for this new event to
9897 * serialize against exec() altering our credentials (and the
9898 * perf_event_exit_task() that could imply).
9901 if (!ptrace_may_access(task, PTRACE_MODE_READ_REALCREDS))
9905 if (flags & PERF_FLAG_PID_CGROUP)
9908 event = perf_event_alloc(&attr, cpu, task, group_leader, NULL,
9909 NULL, NULL, cgroup_fd);
9910 if (IS_ERR(event)) {
9911 err = PTR_ERR(event);
9915 if (is_sampling_event(event)) {
9916 if (event->pmu->capabilities & PERF_PMU_CAP_NO_INTERRUPT) {
9923 * Special case software events and allow them to be part of
9924 * any hardware group.
9928 if (attr.use_clockid) {
9929 err = perf_event_set_clock(event, attr.clockid);
9934 if (pmu->task_ctx_nr == perf_sw_context)
9935 event->event_caps |= PERF_EV_CAP_SOFTWARE;
9938 (is_software_event(event) != is_software_event(group_leader))) {
9939 if (is_software_event(event)) {
9941 * If event and group_leader are not both a software
9942 * event, and event is, then group leader is not.
9944 * Allow the addition of software events to !software
9945 * groups, this is safe because software events never
9948 pmu = group_leader->pmu;
9949 } else if (is_software_event(group_leader) &&
9950 (group_leader->group_caps & PERF_EV_CAP_SOFTWARE)) {
9952 * In case the group is a pure software group, and we
9953 * try to add a hardware event, move the whole group to
9954 * the hardware context.
9961 * Get the target context (task or percpu):
9963 ctx = find_get_context(pmu, task, event);
9969 if ((pmu->capabilities & PERF_PMU_CAP_EXCLUSIVE) && group_leader) {
9975 * Look up the group leader (we will attach this event to it):
9981 * Do not allow a recursive hierarchy (this new sibling
9982 * becoming part of another group-sibling):
9984 if (group_leader->group_leader != group_leader)
9987 /* All events in a group should have the same clock */
9988 if (group_leader->clock != event->clock)
9992 * Do not allow to attach to a group in a different
9993 * task or CPU context:
9997 * Make sure we're both on the same task, or both
10000 if (group_leader->ctx->task != ctx->task)
10004 * Make sure we're both events for the same CPU;
10005 * grouping events for different CPUs is broken; since
10006 * you can never concurrently schedule them anyhow.
10008 if (group_leader->cpu != event->cpu)
10011 if (group_leader->ctx != ctx)
10016 * Only a group leader can be exclusive or pinned
10018 if (attr.exclusive || attr.pinned)
10022 if (output_event) {
10023 err = perf_event_set_output(event, output_event);
10028 event_file = anon_inode_getfile("[perf_event]", &perf_fops, event,
10030 if (IS_ERR(event_file)) {
10031 err = PTR_ERR(event_file);
10037 gctx = __perf_event_ctx_lock_double(group_leader, ctx);
10039 if (gctx->task == TASK_TOMBSTONE) {
10045 * Check if we raced against another sys_perf_event_open() call
10046 * moving the software group underneath us.
10048 if (!(group_leader->group_caps & PERF_EV_CAP_SOFTWARE)) {
10050 * If someone moved the group out from under us, check
10051 * if this new event wound up on the same ctx, if so
10052 * its the regular !move_group case, otherwise fail.
10058 perf_event_ctx_unlock(group_leader, gctx);
10063 mutex_lock(&ctx->mutex);
10066 if (ctx->task == TASK_TOMBSTONE) {
10071 if (!perf_event_validate_size(event)) {
10077 * Must be under the same ctx::mutex as perf_install_in_context(),
10078 * because we need to serialize with concurrent event creation.
10080 if (!exclusive_event_installable(event, ctx)) {
10081 /* exclusive and group stuff are assumed mutually exclusive */
10082 WARN_ON_ONCE(move_group);
10088 WARN_ON_ONCE(ctx->parent_ctx);
10091 * This is the point on no return; we cannot fail hereafter. This is
10092 * where we start modifying current state.
10097 * See perf_event_ctx_lock() for comments on the details
10098 * of swizzling perf_event::ctx.
10100 perf_remove_from_context(group_leader, 0);
10103 list_for_each_entry(sibling, &group_leader->sibling_list,
10105 perf_remove_from_context(sibling, 0);
10110 * Wait for everybody to stop referencing the events through
10111 * the old lists, before installing it on new lists.
10116 * Install the group siblings before the group leader.
10118 * Because a group leader will try and install the entire group
10119 * (through the sibling list, which is still in-tact), we can
10120 * end up with siblings installed in the wrong context.
10122 * By installing siblings first we NO-OP because they're not
10123 * reachable through the group lists.
10125 list_for_each_entry(sibling, &group_leader->sibling_list,
10127 perf_event__state_init(sibling);
10128 perf_install_in_context(ctx, sibling, sibling->cpu);
10133 * Removing from the context ends up with disabled
10134 * event. What we want here is event in the initial
10135 * startup state, ready to be add into new context.
10137 perf_event__state_init(group_leader);
10138 perf_install_in_context(ctx, group_leader, group_leader->cpu);
10143 * Precalculate sample_data sizes; do while holding ctx::mutex such
10144 * that we're serialized against further additions and before
10145 * perf_install_in_context() which is the point the event is active and
10146 * can use these values.
10148 perf_event__header_size(event);
10149 perf_event__id_header_size(event);
10151 event->owner = current;
10153 perf_install_in_context(ctx, event, event->cpu);
10154 perf_unpin_context(ctx);
10157 perf_event_ctx_unlock(group_leader, gctx);
10158 mutex_unlock(&ctx->mutex);
10161 mutex_unlock(&task->signal->cred_guard_mutex);
10162 put_task_struct(task);
10167 mutex_lock(¤t->perf_event_mutex);
10168 list_add_tail(&event->owner_entry, ¤t->perf_event_list);
10169 mutex_unlock(¤t->perf_event_mutex);
10172 * Drop the reference on the group_event after placing the
10173 * new event on the sibling_list. This ensures destruction
10174 * of the group leader will find the pointer to itself in
10175 * perf_group_detach().
10178 fd_install(event_fd, event_file);
10183 perf_event_ctx_unlock(group_leader, gctx);
10184 mutex_unlock(&ctx->mutex);
10188 perf_unpin_context(ctx);
10192 * If event_file is set, the fput() above will have called ->release()
10193 * and that will take care of freeing the event.
10199 mutex_unlock(&task->signal->cred_guard_mutex);
10204 put_task_struct(task);
10208 put_unused_fd(event_fd);
10213 * perf_event_create_kernel_counter
10215 * @attr: attributes of the counter to create
10216 * @cpu: cpu in which the counter is bound
10217 * @task: task to profile (NULL for percpu)
10219 struct perf_event *
10220 perf_event_create_kernel_counter(struct perf_event_attr *attr, int cpu,
10221 struct task_struct *task,
10222 perf_overflow_handler_t overflow_handler,
10225 struct perf_event_context *ctx;
10226 struct perf_event *event;
10230 * Get the target context (task or percpu):
10233 event = perf_event_alloc(attr, cpu, task, NULL, NULL,
10234 overflow_handler, context, -1);
10235 if (IS_ERR(event)) {
10236 err = PTR_ERR(event);
10240 /* Mark owner so we could distinguish it from user events. */
10241 event->owner = TASK_TOMBSTONE;
10243 ctx = find_get_context(event->pmu, task, event);
10245 err = PTR_ERR(ctx);
10249 WARN_ON_ONCE(ctx->parent_ctx);
10250 mutex_lock(&ctx->mutex);
10251 if (ctx->task == TASK_TOMBSTONE) {
10256 if (!exclusive_event_installable(event, ctx)) {
10261 perf_install_in_context(ctx, event, cpu);
10262 perf_unpin_context(ctx);
10263 mutex_unlock(&ctx->mutex);
10268 mutex_unlock(&ctx->mutex);
10269 perf_unpin_context(ctx);
10274 return ERR_PTR(err);
10276 EXPORT_SYMBOL_GPL(perf_event_create_kernel_counter);
10278 void perf_pmu_migrate_context(struct pmu *pmu, int src_cpu, int dst_cpu)
10280 struct perf_event_context *src_ctx;
10281 struct perf_event_context *dst_ctx;
10282 struct perf_event *event, *tmp;
10285 src_ctx = &per_cpu_ptr(pmu->pmu_cpu_context, src_cpu)->ctx;
10286 dst_ctx = &per_cpu_ptr(pmu->pmu_cpu_context, dst_cpu)->ctx;
10289 * See perf_event_ctx_lock() for comments on the details
10290 * of swizzling perf_event::ctx.
10292 mutex_lock_double(&src_ctx->mutex, &dst_ctx->mutex);
10293 list_for_each_entry_safe(event, tmp, &src_ctx->event_list,
10295 perf_remove_from_context(event, 0);
10296 unaccount_event_cpu(event, src_cpu);
10298 list_add(&event->migrate_entry, &events);
10302 * Wait for the events to quiesce before re-instating them.
10307 * Re-instate events in 2 passes.
10309 * Skip over group leaders and only install siblings on this first
10310 * pass, siblings will not get enabled without a leader, however a
10311 * leader will enable its siblings, even if those are still on the old
10314 list_for_each_entry_safe(event, tmp, &events, migrate_entry) {
10315 if (event->group_leader == event)
10318 list_del(&event->migrate_entry);
10319 if (event->state >= PERF_EVENT_STATE_OFF)
10320 event->state = PERF_EVENT_STATE_INACTIVE;
10321 account_event_cpu(event, dst_cpu);
10322 perf_install_in_context(dst_ctx, event, dst_cpu);
10327 * Once all the siblings are setup properly, install the group leaders
10330 list_for_each_entry_safe(event, tmp, &events, migrate_entry) {
10331 list_del(&event->migrate_entry);
10332 if (event->state >= PERF_EVENT_STATE_OFF)
10333 event->state = PERF_EVENT_STATE_INACTIVE;
10334 account_event_cpu(event, dst_cpu);
10335 perf_install_in_context(dst_ctx, event, dst_cpu);
10338 mutex_unlock(&dst_ctx->mutex);
10339 mutex_unlock(&src_ctx->mutex);
10341 EXPORT_SYMBOL_GPL(perf_pmu_migrate_context);
10343 static void sync_child_event(struct perf_event *child_event,
10344 struct task_struct *child)
10346 struct perf_event *parent_event = child_event->parent;
10349 if (child_event->attr.inherit_stat)
10350 perf_event_read_event(child_event, child);
10352 child_val = perf_event_count(child_event);
10355 * Add back the child's count to the parent's count:
10357 atomic64_add(child_val, &parent_event->child_count);
10358 atomic64_add(child_event->total_time_enabled,
10359 &parent_event->child_total_time_enabled);
10360 atomic64_add(child_event->total_time_running,
10361 &parent_event->child_total_time_running);
10365 perf_event_exit_event(struct perf_event *child_event,
10366 struct perf_event_context *child_ctx,
10367 struct task_struct *child)
10369 struct perf_event *parent_event = child_event->parent;
10372 * Do not destroy the 'original' grouping; because of the context
10373 * switch optimization the original events could've ended up in a
10374 * random child task.
10376 * If we were to destroy the original group, all group related
10377 * operations would cease to function properly after this random
10380 * Do destroy all inherited groups, we don't care about those
10381 * and being thorough is better.
10383 raw_spin_lock_irq(&child_ctx->lock);
10384 WARN_ON_ONCE(child_ctx->is_active);
10387 perf_group_detach(child_event);
10388 list_del_event(child_event, child_ctx);
10389 child_event->state = PERF_EVENT_STATE_EXIT; /* is_event_hup() */
10390 raw_spin_unlock_irq(&child_ctx->lock);
10393 * Parent events are governed by their filedesc, retain them.
10395 if (!parent_event) {
10396 perf_event_wakeup(child_event);
10400 * Child events can be cleaned up.
10403 sync_child_event(child_event, child);
10406 * Remove this event from the parent's list
10408 WARN_ON_ONCE(parent_event->ctx->parent_ctx);
10409 mutex_lock(&parent_event->child_mutex);
10410 list_del_init(&child_event->child_list);
10411 mutex_unlock(&parent_event->child_mutex);
10414 * Kick perf_poll() for is_event_hup().
10416 perf_event_wakeup(parent_event);
10417 free_event(child_event);
10418 put_event(parent_event);
10421 static void perf_event_exit_task_context(struct task_struct *child, int ctxn)
10423 struct perf_event_context *child_ctx, *clone_ctx = NULL;
10424 struct perf_event *child_event, *next;
10426 WARN_ON_ONCE(child != current);
10428 child_ctx = perf_pin_task_context(child, ctxn);
10433 * In order to reduce the amount of tricky in ctx tear-down, we hold
10434 * ctx::mutex over the entire thing. This serializes against almost
10435 * everything that wants to access the ctx.
10437 * The exception is sys_perf_event_open() /
10438 * perf_event_create_kernel_count() which does find_get_context()
10439 * without ctx::mutex (it cannot because of the move_group double mutex
10440 * lock thing). See the comments in perf_install_in_context().
10442 mutex_lock(&child_ctx->mutex);
10445 * In a single ctx::lock section, de-schedule the events and detach the
10446 * context from the task such that we cannot ever get it scheduled back
10449 raw_spin_lock_irq(&child_ctx->lock);
10450 task_ctx_sched_out(__get_cpu_context(child_ctx), child_ctx, EVENT_ALL);
10453 * Now that the context is inactive, destroy the task <-> ctx relation
10454 * and mark the context dead.
10456 RCU_INIT_POINTER(child->perf_event_ctxp[ctxn], NULL);
10457 put_ctx(child_ctx); /* cannot be last */
10458 WRITE_ONCE(child_ctx->task, TASK_TOMBSTONE);
10459 put_task_struct(current); /* cannot be last */
10461 clone_ctx = unclone_ctx(child_ctx);
10462 raw_spin_unlock_irq(&child_ctx->lock);
10465 put_ctx(clone_ctx);
10468 * Report the task dead after unscheduling the events so that we
10469 * won't get any samples after PERF_RECORD_EXIT. We can however still
10470 * get a few PERF_RECORD_READ events.
10472 perf_event_task(child, child_ctx, 0);
10474 list_for_each_entry_safe(child_event, next, &child_ctx->event_list, event_entry)
10475 perf_event_exit_event(child_event, child_ctx, child);
10477 mutex_unlock(&child_ctx->mutex);
10479 put_ctx(child_ctx);
10483 * When a child task exits, feed back event values to parent events.
10485 * Can be called with cred_guard_mutex held when called from
10486 * install_exec_creds().
10488 void perf_event_exit_task(struct task_struct *child)
10490 struct perf_event *event, *tmp;
10493 mutex_lock(&child->perf_event_mutex);
10494 list_for_each_entry_safe(event, tmp, &child->perf_event_list,
10496 list_del_init(&event->owner_entry);
10499 * Ensure the list deletion is visible before we clear
10500 * the owner, closes a race against perf_release() where
10501 * we need to serialize on the owner->perf_event_mutex.
10503 smp_store_release(&event->owner, NULL);
10505 mutex_unlock(&child->perf_event_mutex);
10507 for_each_task_context_nr(ctxn)
10508 perf_event_exit_task_context(child, ctxn);
10511 * The perf_event_exit_task_context calls perf_event_task
10512 * with child's task_ctx, which generates EXIT events for
10513 * child contexts and sets child->perf_event_ctxp[] to NULL.
10514 * At this point we need to send EXIT events to cpu contexts.
10516 perf_event_task(child, NULL, 0);
10519 static void perf_free_event(struct perf_event *event,
10520 struct perf_event_context *ctx)
10522 struct perf_event *parent = event->parent;
10524 if (WARN_ON_ONCE(!parent))
10527 mutex_lock(&parent->child_mutex);
10528 list_del_init(&event->child_list);
10529 mutex_unlock(&parent->child_mutex);
10533 raw_spin_lock_irq(&ctx->lock);
10534 perf_group_detach(event);
10535 list_del_event(event, ctx);
10536 raw_spin_unlock_irq(&ctx->lock);
10541 * Free an unexposed, unused context as created by inheritance by
10542 * perf_event_init_task below, used by fork() in case of fail.
10544 * Not all locks are strictly required, but take them anyway to be nice and
10545 * help out with the lockdep assertions.
10547 void perf_event_free_task(struct task_struct *task)
10549 struct perf_event_context *ctx;
10550 struct perf_event *event, *tmp;
10553 for_each_task_context_nr(ctxn) {
10554 ctx = task->perf_event_ctxp[ctxn];
10558 mutex_lock(&ctx->mutex);
10559 raw_spin_lock_irq(&ctx->lock);
10561 * Destroy the task <-> ctx relation and mark the context dead.
10563 * This is important because even though the task hasn't been
10564 * exposed yet the context has been (through child_list).
10566 RCU_INIT_POINTER(task->perf_event_ctxp[ctxn], NULL);
10567 WRITE_ONCE(ctx->task, TASK_TOMBSTONE);
10568 put_task_struct(task); /* cannot be last */
10569 raw_spin_unlock_irq(&ctx->lock);
10571 list_for_each_entry_safe(event, tmp, &ctx->event_list, event_entry)
10572 perf_free_event(event, ctx);
10574 mutex_unlock(&ctx->mutex);
10579 void perf_event_delayed_put(struct task_struct *task)
10583 for_each_task_context_nr(ctxn)
10584 WARN_ON_ONCE(task->perf_event_ctxp[ctxn]);
10587 struct file *perf_event_get(unsigned int fd)
10591 file = fget_raw(fd);
10593 return ERR_PTR(-EBADF);
10595 if (file->f_op != &perf_fops) {
10597 return ERR_PTR(-EBADF);
10603 const struct perf_event_attr *perf_event_attrs(struct perf_event *event)
10606 return ERR_PTR(-EINVAL);
10608 return &event->attr;
10612 * Inherit a event from parent task to child task.
10615 * - valid pointer on success
10616 * - NULL for orphaned events
10617 * - IS_ERR() on error
10619 static struct perf_event *
10620 inherit_event(struct perf_event *parent_event,
10621 struct task_struct *parent,
10622 struct perf_event_context *parent_ctx,
10623 struct task_struct *child,
10624 struct perf_event *group_leader,
10625 struct perf_event_context *child_ctx)
10627 enum perf_event_active_state parent_state = parent_event->state;
10628 struct perf_event *child_event;
10629 unsigned long flags;
10632 * Instead of creating recursive hierarchies of events,
10633 * we link inherited events back to the original parent,
10634 * which has a filp for sure, which we use as the reference
10637 if (parent_event->parent)
10638 parent_event = parent_event->parent;
10640 child_event = perf_event_alloc(&parent_event->attr,
10643 group_leader, parent_event,
10645 if (IS_ERR(child_event))
10646 return child_event;
10649 * is_orphaned_event() and list_add_tail(&parent_event->child_list)
10650 * must be under the same lock in order to serialize against
10651 * perf_event_release_kernel(), such that either we must observe
10652 * is_orphaned_event() or they will observe us on the child_list.
10654 mutex_lock(&parent_event->child_mutex);
10655 if (is_orphaned_event(parent_event) ||
10656 !atomic_long_inc_not_zero(&parent_event->refcount)) {
10657 mutex_unlock(&parent_event->child_mutex);
10658 free_event(child_event);
10662 get_ctx(child_ctx);
10665 * Make the child state follow the state of the parent event,
10666 * not its attr.disabled bit. We hold the parent's mutex,
10667 * so we won't race with perf_event_{en, dis}able_family.
10669 if (parent_state >= PERF_EVENT_STATE_INACTIVE)
10670 child_event->state = PERF_EVENT_STATE_INACTIVE;
10672 child_event->state = PERF_EVENT_STATE_OFF;
10674 if (parent_event->attr.freq) {
10675 u64 sample_period = parent_event->hw.sample_period;
10676 struct hw_perf_event *hwc = &child_event->hw;
10678 hwc->sample_period = sample_period;
10679 hwc->last_period = sample_period;
10681 local64_set(&hwc->period_left, sample_period);
10684 child_event->ctx = child_ctx;
10685 child_event->overflow_handler = parent_event->overflow_handler;
10686 child_event->overflow_handler_context
10687 = parent_event->overflow_handler_context;
10690 * Precalculate sample_data sizes
10692 perf_event__header_size(child_event);
10693 perf_event__id_header_size(child_event);
10696 * Link it up in the child's context:
10698 raw_spin_lock_irqsave(&child_ctx->lock, flags);
10699 add_event_to_ctx(child_event, child_ctx);
10700 raw_spin_unlock_irqrestore(&child_ctx->lock, flags);
10703 * Link this into the parent event's child list
10705 list_add_tail(&child_event->child_list, &parent_event->child_list);
10706 mutex_unlock(&parent_event->child_mutex);
10708 return child_event;
10712 * Inherits an event group.
10714 * This will quietly suppress orphaned events; !inherit_event() is not an error.
10715 * This matches with perf_event_release_kernel() removing all child events.
10721 static int inherit_group(struct perf_event *parent_event,
10722 struct task_struct *parent,
10723 struct perf_event_context *parent_ctx,
10724 struct task_struct *child,
10725 struct perf_event_context *child_ctx)
10727 struct perf_event *leader;
10728 struct perf_event *sub;
10729 struct perf_event *child_ctr;
10731 leader = inherit_event(parent_event, parent, parent_ctx,
10732 child, NULL, child_ctx);
10733 if (IS_ERR(leader))
10734 return PTR_ERR(leader);
10736 * @leader can be NULL here because of is_orphaned_event(). In this
10737 * case inherit_event() will create individual events, similar to what
10738 * perf_group_detach() would do anyway.
10740 list_for_each_entry(sub, &parent_event->sibling_list, group_entry) {
10741 child_ctr = inherit_event(sub, parent, parent_ctx,
10742 child, leader, child_ctx);
10743 if (IS_ERR(child_ctr))
10744 return PTR_ERR(child_ctr);
10750 * Creates the child task context and tries to inherit the event-group.
10752 * Clears @inherited_all on !attr.inherited or error. Note that we'll leave
10753 * inherited_all set when we 'fail' to inherit an orphaned event; this is
10754 * consistent with perf_event_release_kernel() removing all child events.
10761 inherit_task_group(struct perf_event *event, struct task_struct *parent,
10762 struct perf_event_context *parent_ctx,
10763 struct task_struct *child, int ctxn,
10764 int *inherited_all)
10767 struct perf_event_context *child_ctx;
10769 if (!event->attr.inherit) {
10770 *inherited_all = 0;
10774 child_ctx = child->perf_event_ctxp[ctxn];
10777 * This is executed from the parent task context, so
10778 * inherit events that have been marked for cloning.
10779 * First allocate and initialize a context for the
10782 child_ctx = alloc_perf_context(parent_ctx->pmu, child);
10786 child->perf_event_ctxp[ctxn] = child_ctx;
10789 ret = inherit_group(event, parent, parent_ctx,
10793 *inherited_all = 0;
10799 * Initialize the perf_event context in task_struct
10801 static int perf_event_init_context(struct task_struct *child, int ctxn)
10803 struct perf_event_context *child_ctx, *parent_ctx;
10804 struct perf_event_context *cloned_ctx;
10805 struct perf_event *event;
10806 struct task_struct *parent = current;
10807 int inherited_all = 1;
10808 unsigned long flags;
10811 if (likely(!parent->perf_event_ctxp[ctxn]))
10815 * If the parent's context is a clone, pin it so it won't get
10816 * swapped under us.
10818 parent_ctx = perf_pin_task_context(parent, ctxn);
10823 * No need to check if parent_ctx != NULL here; since we saw
10824 * it non-NULL earlier, the only reason for it to become NULL
10825 * is if we exit, and since we're currently in the middle of
10826 * a fork we can't be exiting at the same time.
10830 * Lock the parent list. No need to lock the child - not PID
10831 * hashed yet and not running, so nobody can access it.
10833 mutex_lock(&parent_ctx->mutex);
10836 * We dont have to disable NMIs - we are only looking at
10837 * the list, not manipulating it:
10839 list_for_each_entry(event, &parent_ctx->pinned_groups, group_entry) {
10840 ret = inherit_task_group(event, parent, parent_ctx,
10841 child, ctxn, &inherited_all);
10847 * We can't hold ctx->lock when iterating the ->flexible_group list due
10848 * to allocations, but we need to prevent rotation because
10849 * rotate_ctx() will change the list from interrupt context.
10851 raw_spin_lock_irqsave(&parent_ctx->lock, flags);
10852 parent_ctx->rotate_disable = 1;
10853 raw_spin_unlock_irqrestore(&parent_ctx->lock, flags);
10855 list_for_each_entry(event, &parent_ctx->flexible_groups, group_entry) {
10856 ret = inherit_task_group(event, parent, parent_ctx,
10857 child, ctxn, &inherited_all);
10862 raw_spin_lock_irqsave(&parent_ctx->lock, flags);
10863 parent_ctx->rotate_disable = 0;
10865 child_ctx = child->perf_event_ctxp[ctxn];
10867 if (child_ctx && inherited_all) {
10869 * Mark the child context as a clone of the parent
10870 * context, or of whatever the parent is a clone of.
10872 * Note that if the parent is a clone, the holding of
10873 * parent_ctx->lock avoids it from being uncloned.
10875 cloned_ctx = parent_ctx->parent_ctx;
10877 child_ctx->parent_ctx = cloned_ctx;
10878 child_ctx->parent_gen = parent_ctx->parent_gen;
10880 child_ctx->parent_ctx = parent_ctx;
10881 child_ctx->parent_gen = parent_ctx->generation;
10883 get_ctx(child_ctx->parent_ctx);
10886 raw_spin_unlock_irqrestore(&parent_ctx->lock, flags);
10888 mutex_unlock(&parent_ctx->mutex);
10890 perf_unpin_context(parent_ctx);
10891 put_ctx(parent_ctx);
10897 * Initialize the perf_event context in task_struct
10899 int perf_event_init_task(struct task_struct *child)
10903 memset(child->perf_event_ctxp, 0, sizeof(child->perf_event_ctxp));
10904 mutex_init(&child->perf_event_mutex);
10905 INIT_LIST_HEAD(&child->perf_event_list);
10907 for_each_task_context_nr(ctxn) {
10908 ret = perf_event_init_context(child, ctxn);
10910 perf_event_free_task(child);
10918 static void __init perf_event_init_all_cpus(void)
10920 struct swevent_htable *swhash;
10923 for_each_possible_cpu(cpu) {
10924 swhash = &per_cpu(swevent_htable, cpu);
10925 mutex_init(&swhash->hlist_mutex);
10926 INIT_LIST_HEAD(&per_cpu(active_ctx_list, cpu));
10928 INIT_LIST_HEAD(&per_cpu(pmu_sb_events.list, cpu));
10929 raw_spin_lock_init(&per_cpu(pmu_sb_events.lock, cpu));
10931 #ifdef CONFIG_CGROUP_PERF
10932 INIT_LIST_HEAD(&per_cpu(cgrp_cpuctx_list, cpu));
10934 INIT_LIST_HEAD(&per_cpu(sched_cb_list, cpu));
10938 int perf_event_init_cpu(unsigned int cpu)
10940 struct swevent_htable *swhash = &per_cpu(swevent_htable, cpu);
10942 mutex_lock(&swhash->hlist_mutex);
10943 if (swhash->hlist_refcount > 0 && !swevent_hlist_deref(swhash)) {
10944 struct swevent_hlist *hlist;
10946 hlist = kzalloc_node(sizeof(*hlist), GFP_KERNEL, cpu_to_node(cpu));
10948 rcu_assign_pointer(swhash->swevent_hlist, hlist);
10950 mutex_unlock(&swhash->hlist_mutex);
10954 #if defined CONFIG_HOTPLUG_CPU || defined CONFIG_KEXEC_CORE
10955 static void __perf_event_exit_context(void *__info)
10957 struct perf_event_context *ctx = __info;
10958 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
10959 struct perf_event *event;
10961 raw_spin_lock(&ctx->lock);
10962 list_for_each_entry(event, &ctx->event_list, event_entry)
10963 __perf_remove_from_context(event, cpuctx, ctx, (void *)DETACH_GROUP);
10964 raw_spin_unlock(&ctx->lock);
10967 static void perf_event_exit_cpu_context(int cpu)
10969 struct perf_event_context *ctx;
10973 idx = srcu_read_lock(&pmus_srcu);
10974 list_for_each_entry_rcu(pmu, &pmus, entry) {
10975 ctx = &per_cpu_ptr(pmu->pmu_cpu_context, cpu)->ctx;
10977 mutex_lock(&ctx->mutex);
10978 smp_call_function_single(cpu, __perf_event_exit_context, ctx, 1);
10979 mutex_unlock(&ctx->mutex);
10981 srcu_read_unlock(&pmus_srcu, idx);
10985 static void perf_event_exit_cpu_context(int cpu) { }
10989 int perf_event_exit_cpu(unsigned int cpu)
10991 perf_event_exit_cpu_context(cpu);
10996 perf_reboot(struct notifier_block *notifier, unsigned long val, void *v)
11000 for_each_online_cpu(cpu)
11001 perf_event_exit_cpu(cpu);
11007 * Run the perf reboot notifier at the very last possible moment so that
11008 * the generic watchdog code runs as long as possible.
11010 static struct notifier_block perf_reboot_notifier = {
11011 .notifier_call = perf_reboot,
11012 .priority = INT_MIN,
11015 void __init perf_event_init(void)
11019 idr_init(&pmu_idr);
11021 perf_event_init_all_cpus();
11022 init_srcu_struct(&pmus_srcu);
11023 perf_pmu_register(&perf_swevent, "software", PERF_TYPE_SOFTWARE);
11024 perf_pmu_register(&perf_cpu_clock, NULL, -1);
11025 perf_pmu_register(&perf_task_clock, NULL, -1);
11026 perf_tp_register();
11027 perf_event_init_cpu(smp_processor_id());
11028 register_reboot_notifier(&perf_reboot_notifier);
11030 ret = init_hw_breakpoint();
11031 WARN(ret, "hw_breakpoint initialization failed with: %d", ret);
11034 * Build time assertion that we keep the data_head at the intended
11035 * location. IOW, validation we got the __reserved[] size right.
11037 BUILD_BUG_ON((offsetof(struct perf_event_mmap_page, data_head))
11041 ssize_t perf_event_sysfs_show(struct device *dev, struct device_attribute *attr,
11044 struct perf_pmu_events_attr *pmu_attr =
11045 container_of(attr, struct perf_pmu_events_attr, attr);
11047 if (pmu_attr->event_str)
11048 return sprintf(page, "%s\n", pmu_attr->event_str);
11052 EXPORT_SYMBOL_GPL(perf_event_sysfs_show);
11054 static int __init perf_event_sysfs_init(void)
11059 mutex_lock(&pmus_lock);
11061 ret = bus_register(&pmu_bus);
11065 list_for_each_entry(pmu, &pmus, entry) {
11066 if (!pmu->name || pmu->type < 0)
11069 ret = pmu_dev_alloc(pmu);
11070 WARN(ret, "Failed to register pmu: %s, reason %d\n", pmu->name, ret);
11072 pmu_bus_running = 1;
11076 mutex_unlock(&pmus_lock);
11080 device_initcall(perf_event_sysfs_init);
11082 #ifdef CONFIG_CGROUP_PERF
11083 static struct cgroup_subsys_state *
11084 perf_cgroup_css_alloc(struct cgroup_subsys_state *parent_css)
11086 struct perf_cgroup *jc;
11088 jc = kzalloc(sizeof(*jc), GFP_KERNEL);
11090 return ERR_PTR(-ENOMEM);
11092 jc->info = alloc_percpu(struct perf_cgroup_info);
11095 return ERR_PTR(-ENOMEM);
11101 static void perf_cgroup_css_free(struct cgroup_subsys_state *css)
11103 struct perf_cgroup *jc = container_of(css, struct perf_cgroup, css);
11105 free_percpu(jc->info);
11109 static int __perf_cgroup_move(void *info)
11111 struct task_struct *task = info;
11113 perf_cgroup_switch(task, PERF_CGROUP_SWOUT | PERF_CGROUP_SWIN);
11118 static void perf_cgroup_attach(struct cgroup_taskset *tset)
11120 struct task_struct *task;
11121 struct cgroup_subsys_state *css;
11123 cgroup_taskset_for_each(task, css, tset)
11124 task_function_call(task, __perf_cgroup_move, task);
11127 struct cgroup_subsys perf_event_cgrp_subsys = {
11128 .css_alloc = perf_cgroup_css_alloc,
11129 .css_free = perf_cgroup_css_free,
11130 .attach = perf_cgroup_attach,
11132 * Implicitly enable on dfl hierarchy so that perf events can
11133 * always be filtered by cgroup2 path as long as perf_event
11134 * controller is not mounted on a legacy hierarchy.
11136 .implicit_on_dfl = true,
11138 #endif /* CONFIG_CGROUP_PERF */