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;
392 static cpumask_var_t perf_online_mask;
395 * perf event paranoia level:
396 * -1 - not paranoid at all
397 * 0 - disallow raw tracepoint access for unpriv
398 * 1 - disallow cpu events for unpriv
399 * 2 - disallow kernel profiling for unpriv
401 int sysctl_perf_event_paranoid __read_mostly = 2;
403 /* Minimum for 512 kiB + 1 user control page */
404 int sysctl_perf_event_mlock __read_mostly = 512 + (PAGE_SIZE / 1024); /* 'free' kiB per user */
407 * max perf event sample rate
409 #define DEFAULT_MAX_SAMPLE_RATE 100000
410 #define DEFAULT_SAMPLE_PERIOD_NS (NSEC_PER_SEC / DEFAULT_MAX_SAMPLE_RATE)
411 #define DEFAULT_CPU_TIME_MAX_PERCENT 25
413 int sysctl_perf_event_sample_rate __read_mostly = DEFAULT_MAX_SAMPLE_RATE;
415 static int max_samples_per_tick __read_mostly = DIV_ROUND_UP(DEFAULT_MAX_SAMPLE_RATE, HZ);
416 static int perf_sample_period_ns __read_mostly = DEFAULT_SAMPLE_PERIOD_NS;
418 static int perf_sample_allowed_ns __read_mostly =
419 DEFAULT_SAMPLE_PERIOD_NS * DEFAULT_CPU_TIME_MAX_PERCENT / 100;
421 static void update_perf_cpu_limits(void)
423 u64 tmp = perf_sample_period_ns;
425 tmp *= sysctl_perf_cpu_time_max_percent;
426 tmp = div_u64(tmp, 100);
430 WRITE_ONCE(perf_sample_allowed_ns, tmp);
433 static int perf_rotate_context(struct perf_cpu_context *cpuctx);
435 int perf_proc_update_handler(struct ctl_table *table, int write,
436 void __user *buffer, size_t *lenp,
439 int ret = proc_dointvec_minmax(table, write, buffer, lenp, ppos);
445 * If throttling is disabled don't allow the write:
447 if (sysctl_perf_cpu_time_max_percent == 100 ||
448 sysctl_perf_cpu_time_max_percent == 0)
451 max_samples_per_tick = DIV_ROUND_UP(sysctl_perf_event_sample_rate, HZ);
452 perf_sample_period_ns = NSEC_PER_SEC / sysctl_perf_event_sample_rate;
453 update_perf_cpu_limits();
458 int sysctl_perf_cpu_time_max_percent __read_mostly = DEFAULT_CPU_TIME_MAX_PERCENT;
460 int perf_cpu_time_max_percent_handler(struct ctl_table *table, int write,
461 void __user *buffer, size_t *lenp,
464 int ret = proc_dointvec_minmax(table, write, buffer, lenp, ppos);
469 if (sysctl_perf_cpu_time_max_percent == 100 ||
470 sysctl_perf_cpu_time_max_percent == 0) {
472 "perf: Dynamic interrupt throttling disabled, can hang your system!\n");
473 WRITE_ONCE(perf_sample_allowed_ns, 0);
475 update_perf_cpu_limits();
482 * perf samples are done in some very critical code paths (NMIs).
483 * If they take too much CPU time, the system can lock up and not
484 * get any real work done. This will drop the sample rate when
485 * we detect that events are taking too long.
487 #define NR_ACCUMULATED_SAMPLES 128
488 static DEFINE_PER_CPU(u64, running_sample_length);
490 static u64 __report_avg;
491 static u64 __report_allowed;
493 static void perf_duration_warn(struct irq_work *w)
495 printk_ratelimited(KERN_INFO
496 "perf: interrupt took too long (%lld > %lld), lowering "
497 "kernel.perf_event_max_sample_rate to %d\n",
498 __report_avg, __report_allowed,
499 sysctl_perf_event_sample_rate);
502 static DEFINE_IRQ_WORK(perf_duration_work, perf_duration_warn);
504 void perf_sample_event_took(u64 sample_len_ns)
506 u64 max_len = READ_ONCE(perf_sample_allowed_ns);
514 /* Decay the counter by 1 average sample. */
515 running_len = __this_cpu_read(running_sample_length);
516 running_len -= running_len/NR_ACCUMULATED_SAMPLES;
517 running_len += sample_len_ns;
518 __this_cpu_write(running_sample_length, running_len);
521 * Note: this will be biased artifically low until we have
522 * seen NR_ACCUMULATED_SAMPLES. Doing it this way keeps us
523 * from having to maintain a count.
525 avg_len = running_len/NR_ACCUMULATED_SAMPLES;
526 if (avg_len <= max_len)
529 __report_avg = avg_len;
530 __report_allowed = max_len;
533 * Compute a throttle threshold 25% below the current duration.
535 avg_len += avg_len / 4;
536 max = (TICK_NSEC / 100) * sysctl_perf_cpu_time_max_percent;
542 WRITE_ONCE(perf_sample_allowed_ns, avg_len);
543 WRITE_ONCE(max_samples_per_tick, max);
545 sysctl_perf_event_sample_rate = max * HZ;
546 perf_sample_period_ns = NSEC_PER_SEC / sysctl_perf_event_sample_rate;
548 if (!irq_work_queue(&perf_duration_work)) {
549 early_printk("perf: interrupt took too long (%lld > %lld), lowering "
550 "kernel.perf_event_max_sample_rate to %d\n",
551 __report_avg, __report_allowed,
552 sysctl_perf_event_sample_rate);
556 static atomic64_t perf_event_id;
558 static void cpu_ctx_sched_out(struct perf_cpu_context *cpuctx,
559 enum event_type_t event_type);
561 static void cpu_ctx_sched_in(struct perf_cpu_context *cpuctx,
562 enum event_type_t event_type,
563 struct task_struct *task);
565 static void update_context_time(struct perf_event_context *ctx);
566 static u64 perf_event_time(struct perf_event *event);
568 void __weak perf_event_print_debug(void) { }
570 extern __weak const char *perf_pmu_name(void)
575 static inline u64 perf_clock(void)
577 return local_clock();
580 static inline u64 perf_event_clock(struct perf_event *event)
582 return event->clock();
585 #ifdef CONFIG_CGROUP_PERF
588 perf_cgroup_match(struct perf_event *event)
590 struct perf_event_context *ctx = event->ctx;
591 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
593 /* @event doesn't care about cgroup */
597 /* wants specific cgroup scope but @cpuctx isn't associated with any */
602 * Cgroup scoping is recursive. An event enabled for a cgroup is
603 * also enabled for all its descendant cgroups. If @cpuctx's
604 * cgroup is a descendant of @event's (the test covers identity
605 * case), it's a match.
607 return cgroup_is_descendant(cpuctx->cgrp->css.cgroup,
608 event->cgrp->css.cgroup);
611 static inline void perf_detach_cgroup(struct perf_event *event)
613 css_put(&event->cgrp->css);
617 static inline int is_cgroup_event(struct perf_event *event)
619 return event->cgrp != NULL;
622 static inline u64 perf_cgroup_event_time(struct perf_event *event)
624 struct perf_cgroup_info *t;
626 t = per_cpu_ptr(event->cgrp->info, event->cpu);
630 static inline void __update_cgrp_time(struct perf_cgroup *cgrp)
632 struct perf_cgroup_info *info;
637 info = this_cpu_ptr(cgrp->info);
639 info->time += now - info->timestamp;
640 info->timestamp = now;
643 static inline void update_cgrp_time_from_cpuctx(struct perf_cpu_context *cpuctx)
645 struct perf_cgroup *cgrp_out = cpuctx->cgrp;
647 __update_cgrp_time(cgrp_out);
650 static inline void update_cgrp_time_from_event(struct perf_event *event)
652 struct perf_cgroup *cgrp;
655 * ensure we access cgroup data only when needed and
656 * when we know the cgroup is pinned (css_get)
658 if (!is_cgroup_event(event))
661 cgrp = perf_cgroup_from_task(current, event->ctx);
663 * Do not update time when cgroup is not active
665 if (cgrp == event->cgrp)
666 __update_cgrp_time(event->cgrp);
670 perf_cgroup_set_timestamp(struct task_struct *task,
671 struct perf_event_context *ctx)
673 struct perf_cgroup *cgrp;
674 struct perf_cgroup_info *info;
677 * ctx->lock held by caller
678 * ensure we do not access cgroup data
679 * unless we have the cgroup pinned (css_get)
681 if (!task || !ctx->nr_cgroups)
684 cgrp = perf_cgroup_from_task(task, ctx);
685 info = this_cpu_ptr(cgrp->info);
686 info->timestamp = ctx->timestamp;
689 static DEFINE_PER_CPU(struct list_head, cgrp_cpuctx_list);
691 #define PERF_CGROUP_SWOUT 0x1 /* cgroup switch out every event */
692 #define PERF_CGROUP_SWIN 0x2 /* cgroup switch in events based on task */
695 * reschedule events based on the cgroup constraint of task.
697 * mode SWOUT : schedule out everything
698 * mode SWIN : schedule in based on cgroup for next
700 static void perf_cgroup_switch(struct task_struct *task, int mode)
702 struct perf_cpu_context *cpuctx;
703 struct list_head *list;
707 * Disable interrupts and preemption to avoid this CPU's
708 * cgrp_cpuctx_entry to change under us.
710 local_irq_save(flags);
712 list = this_cpu_ptr(&cgrp_cpuctx_list);
713 list_for_each_entry(cpuctx, list, cgrp_cpuctx_entry) {
714 WARN_ON_ONCE(cpuctx->ctx.nr_cgroups == 0);
716 perf_ctx_lock(cpuctx, cpuctx->task_ctx);
717 perf_pmu_disable(cpuctx->ctx.pmu);
719 if (mode & PERF_CGROUP_SWOUT) {
720 cpu_ctx_sched_out(cpuctx, EVENT_ALL);
722 * must not be done before ctxswout due
723 * to event_filter_match() in event_sched_out()
728 if (mode & PERF_CGROUP_SWIN) {
729 WARN_ON_ONCE(cpuctx->cgrp);
731 * set cgrp before ctxsw in to allow
732 * event_filter_match() to not have to pass
734 * we pass the cpuctx->ctx to perf_cgroup_from_task()
735 * because cgorup events are only per-cpu
737 cpuctx->cgrp = perf_cgroup_from_task(task,
739 cpu_ctx_sched_in(cpuctx, EVENT_ALL, task);
741 perf_pmu_enable(cpuctx->ctx.pmu);
742 perf_ctx_unlock(cpuctx, cpuctx->task_ctx);
745 local_irq_restore(flags);
748 static inline void perf_cgroup_sched_out(struct task_struct *task,
749 struct task_struct *next)
751 struct perf_cgroup *cgrp1;
752 struct perf_cgroup *cgrp2 = NULL;
756 * we come here when we know perf_cgroup_events > 0
757 * we do not need to pass the ctx here because we know
758 * we are holding the rcu lock
760 cgrp1 = perf_cgroup_from_task(task, NULL);
761 cgrp2 = perf_cgroup_from_task(next, NULL);
764 * only schedule out current cgroup events if we know
765 * that we are switching to a different cgroup. Otherwise,
766 * do no touch the cgroup events.
769 perf_cgroup_switch(task, PERF_CGROUP_SWOUT);
774 static inline void perf_cgroup_sched_in(struct task_struct *prev,
775 struct task_struct *task)
777 struct perf_cgroup *cgrp1;
778 struct perf_cgroup *cgrp2 = NULL;
782 * we come here when we know perf_cgroup_events > 0
783 * we do not need to pass the ctx here because we know
784 * we are holding the rcu lock
786 cgrp1 = perf_cgroup_from_task(task, NULL);
787 cgrp2 = perf_cgroup_from_task(prev, NULL);
790 * only need to schedule in cgroup events if we are changing
791 * cgroup during ctxsw. Cgroup events were not scheduled
792 * out of ctxsw out if that was not the case.
795 perf_cgroup_switch(task, PERF_CGROUP_SWIN);
800 static inline int perf_cgroup_connect(int fd, struct perf_event *event,
801 struct perf_event_attr *attr,
802 struct perf_event *group_leader)
804 struct perf_cgroup *cgrp;
805 struct cgroup_subsys_state *css;
806 struct fd f = fdget(fd);
812 css = css_tryget_online_from_dir(f.file->f_path.dentry,
813 &perf_event_cgrp_subsys);
819 cgrp = container_of(css, struct perf_cgroup, css);
823 * all events in a group must monitor
824 * the same cgroup because a task belongs
825 * to only one perf cgroup at a time
827 if (group_leader && group_leader->cgrp != cgrp) {
828 perf_detach_cgroup(event);
837 perf_cgroup_set_shadow_time(struct perf_event *event, u64 now)
839 struct perf_cgroup_info *t;
840 t = per_cpu_ptr(event->cgrp->info, event->cpu);
841 event->shadow_ctx_time = now - t->timestamp;
845 perf_cgroup_defer_enabled(struct perf_event *event)
848 * when the current task's perf cgroup does not match
849 * the event's, we need to remember to call the
850 * perf_mark_enable() function the first time a task with
851 * a matching perf cgroup is scheduled in.
853 if (is_cgroup_event(event) && !perf_cgroup_match(event))
854 event->cgrp_defer_enabled = 1;
858 perf_cgroup_mark_enabled(struct perf_event *event,
859 struct perf_event_context *ctx)
861 struct perf_event *sub;
862 u64 tstamp = perf_event_time(event);
864 if (!event->cgrp_defer_enabled)
867 event->cgrp_defer_enabled = 0;
869 event->tstamp_enabled = tstamp - event->total_time_enabled;
870 list_for_each_entry(sub, &event->sibling_list, group_entry) {
871 if (sub->state >= PERF_EVENT_STATE_INACTIVE) {
872 sub->tstamp_enabled = tstamp - sub->total_time_enabled;
873 sub->cgrp_defer_enabled = 0;
879 * Update cpuctx->cgrp so that it is set when first cgroup event is added and
880 * cleared when last cgroup event is removed.
883 list_update_cgroup_event(struct perf_event *event,
884 struct perf_event_context *ctx, bool add)
886 struct perf_cpu_context *cpuctx;
887 struct list_head *cpuctx_entry;
889 if (!is_cgroup_event(event))
892 if (add && ctx->nr_cgroups++)
894 else if (!add && --ctx->nr_cgroups)
897 * Because cgroup events are always per-cpu events,
898 * this will always be called from the right CPU.
900 cpuctx = __get_cpu_context(ctx);
901 cpuctx_entry = &cpuctx->cgrp_cpuctx_entry;
902 /* cpuctx->cgrp is NULL unless a cgroup event is active in this CPU .*/
904 list_add(cpuctx_entry, this_cpu_ptr(&cgrp_cpuctx_list));
905 if (perf_cgroup_from_task(current, ctx) == event->cgrp)
906 cpuctx->cgrp = event->cgrp;
908 list_del(cpuctx_entry);
913 #else /* !CONFIG_CGROUP_PERF */
916 perf_cgroup_match(struct perf_event *event)
921 static inline void perf_detach_cgroup(struct perf_event *event)
924 static inline int is_cgroup_event(struct perf_event *event)
929 static inline void update_cgrp_time_from_event(struct perf_event *event)
933 static inline void update_cgrp_time_from_cpuctx(struct perf_cpu_context *cpuctx)
937 static inline void perf_cgroup_sched_out(struct task_struct *task,
938 struct task_struct *next)
942 static inline void perf_cgroup_sched_in(struct task_struct *prev,
943 struct task_struct *task)
947 static inline int perf_cgroup_connect(pid_t pid, struct perf_event *event,
948 struct perf_event_attr *attr,
949 struct perf_event *group_leader)
955 perf_cgroup_set_timestamp(struct task_struct *task,
956 struct perf_event_context *ctx)
961 perf_cgroup_switch(struct task_struct *task, struct task_struct *next)
966 perf_cgroup_set_shadow_time(struct perf_event *event, u64 now)
970 static inline u64 perf_cgroup_event_time(struct perf_event *event)
976 perf_cgroup_defer_enabled(struct perf_event *event)
981 perf_cgroup_mark_enabled(struct perf_event *event,
982 struct perf_event_context *ctx)
987 list_update_cgroup_event(struct perf_event *event,
988 struct perf_event_context *ctx, bool add)
995 * set default to be dependent on timer tick just
998 #define PERF_CPU_HRTIMER (1000 / HZ)
1000 * function must be called with interrupts disabled
1002 static enum hrtimer_restart perf_mux_hrtimer_handler(struct hrtimer *hr)
1004 struct perf_cpu_context *cpuctx;
1007 WARN_ON(!irqs_disabled());
1009 cpuctx = container_of(hr, struct perf_cpu_context, hrtimer);
1010 rotations = perf_rotate_context(cpuctx);
1012 raw_spin_lock(&cpuctx->hrtimer_lock);
1014 hrtimer_forward_now(hr, cpuctx->hrtimer_interval);
1016 cpuctx->hrtimer_active = 0;
1017 raw_spin_unlock(&cpuctx->hrtimer_lock);
1019 return rotations ? HRTIMER_RESTART : HRTIMER_NORESTART;
1022 static void __perf_mux_hrtimer_init(struct perf_cpu_context *cpuctx, int cpu)
1024 struct hrtimer *timer = &cpuctx->hrtimer;
1025 struct pmu *pmu = cpuctx->ctx.pmu;
1028 /* no multiplexing needed for SW PMU */
1029 if (pmu->task_ctx_nr == perf_sw_context)
1033 * check default is sane, if not set then force to
1034 * default interval (1/tick)
1036 interval = pmu->hrtimer_interval_ms;
1038 interval = pmu->hrtimer_interval_ms = PERF_CPU_HRTIMER;
1040 cpuctx->hrtimer_interval = ns_to_ktime(NSEC_PER_MSEC * interval);
1042 raw_spin_lock_init(&cpuctx->hrtimer_lock);
1043 hrtimer_init(timer, CLOCK_MONOTONIC, HRTIMER_MODE_ABS_PINNED);
1044 timer->function = perf_mux_hrtimer_handler;
1047 static int perf_mux_hrtimer_restart(struct perf_cpu_context *cpuctx)
1049 struct hrtimer *timer = &cpuctx->hrtimer;
1050 struct pmu *pmu = cpuctx->ctx.pmu;
1051 unsigned long flags;
1053 /* not for SW PMU */
1054 if (pmu->task_ctx_nr == perf_sw_context)
1057 raw_spin_lock_irqsave(&cpuctx->hrtimer_lock, flags);
1058 if (!cpuctx->hrtimer_active) {
1059 cpuctx->hrtimer_active = 1;
1060 hrtimer_forward_now(timer, cpuctx->hrtimer_interval);
1061 hrtimer_start_expires(timer, HRTIMER_MODE_ABS_PINNED);
1063 raw_spin_unlock_irqrestore(&cpuctx->hrtimer_lock, flags);
1068 void perf_pmu_disable(struct pmu *pmu)
1070 int *count = this_cpu_ptr(pmu->pmu_disable_count);
1072 pmu->pmu_disable(pmu);
1075 void perf_pmu_enable(struct pmu *pmu)
1077 int *count = this_cpu_ptr(pmu->pmu_disable_count);
1079 pmu->pmu_enable(pmu);
1082 static DEFINE_PER_CPU(struct list_head, active_ctx_list);
1085 * perf_event_ctx_activate(), perf_event_ctx_deactivate(), and
1086 * perf_event_task_tick() are fully serialized because they're strictly cpu
1087 * affine and perf_event_ctx{activate,deactivate} are called with IRQs
1088 * disabled, while perf_event_task_tick is called from IRQ context.
1090 static void perf_event_ctx_activate(struct perf_event_context *ctx)
1092 struct list_head *head = this_cpu_ptr(&active_ctx_list);
1094 WARN_ON(!irqs_disabled());
1096 WARN_ON(!list_empty(&ctx->active_ctx_list));
1098 list_add(&ctx->active_ctx_list, head);
1101 static void perf_event_ctx_deactivate(struct perf_event_context *ctx)
1103 WARN_ON(!irqs_disabled());
1105 WARN_ON(list_empty(&ctx->active_ctx_list));
1107 list_del_init(&ctx->active_ctx_list);
1110 static void get_ctx(struct perf_event_context *ctx)
1112 WARN_ON(!atomic_inc_not_zero(&ctx->refcount));
1115 static void free_ctx(struct rcu_head *head)
1117 struct perf_event_context *ctx;
1119 ctx = container_of(head, struct perf_event_context, rcu_head);
1120 kfree(ctx->task_ctx_data);
1124 static void put_ctx(struct perf_event_context *ctx)
1126 if (atomic_dec_and_test(&ctx->refcount)) {
1127 if (ctx->parent_ctx)
1128 put_ctx(ctx->parent_ctx);
1129 if (ctx->task && ctx->task != TASK_TOMBSTONE)
1130 put_task_struct(ctx->task);
1131 call_rcu(&ctx->rcu_head, free_ctx);
1136 * Because of perf_event::ctx migration in sys_perf_event_open::move_group and
1137 * perf_pmu_migrate_context() we need some magic.
1139 * Those places that change perf_event::ctx will hold both
1140 * perf_event_ctx::mutex of the 'old' and 'new' ctx value.
1142 * Lock ordering is by mutex address. There are two other sites where
1143 * perf_event_context::mutex nests and those are:
1145 * - perf_event_exit_task_context() [ child , 0 ]
1146 * perf_event_exit_event()
1147 * put_event() [ parent, 1 ]
1149 * - perf_event_init_context() [ parent, 0 ]
1150 * inherit_task_group()
1153 * perf_event_alloc()
1155 * perf_try_init_event() [ child , 1 ]
1157 * While it appears there is an obvious deadlock here -- the parent and child
1158 * nesting levels are inverted between the two. This is in fact safe because
1159 * life-time rules separate them. That is an exiting task cannot fork, and a
1160 * spawning task cannot (yet) exit.
1162 * But remember that that these are parent<->child context relations, and
1163 * migration does not affect children, therefore these two orderings should not
1166 * The change in perf_event::ctx does not affect children (as claimed above)
1167 * because the sys_perf_event_open() case will install a new event and break
1168 * the ctx parent<->child relation, and perf_pmu_migrate_context() is only
1169 * concerned with cpuctx and that doesn't have children.
1171 * The places that change perf_event::ctx will issue:
1173 * perf_remove_from_context();
1174 * synchronize_rcu();
1175 * perf_install_in_context();
1177 * to affect the change. The remove_from_context() + synchronize_rcu() should
1178 * quiesce the event, after which we can install it in the new location. This
1179 * means that only external vectors (perf_fops, prctl) can perturb the event
1180 * while in transit. Therefore all such accessors should also acquire
1181 * perf_event_context::mutex to serialize against this.
1183 * However; because event->ctx can change while we're waiting to acquire
1184 * ctx->mutex we must be careful and use the below perf_event_ctx_lock()
1189 * task_struct::perf_event_mutex
1190 * perf_event_context::mutex
1191 * perf_event::child_mutex;
1192 * perf_event_context::lock
1193 * perf_event::mmap_mutex
1196 static struct perf_event_context *
1197 perf_event_ctx_lock_nested(struct perf_event *event, int nesting)
1199 struct perf_event_context *ctx;
1203 ctx = ACCESS_ONCE(event->ctx);
1204 if (!atomic_inc_not_zero(&ctx->refcount)) {
1210 mutex_lock_nested(&ctx->mutex, nesting);
1211 if (event->ctx != ctx) {
1212 mutex_unlock(&ctx->mutex);
1220 static inline struct perf_event_context *
1221 perf_event_ctx_lock(struct perf_event *event)
1223 return perf_event_ctx_lock_nested(event, 0);
1226 static void perf_event_ctx_unlock(struct perf_event *event,
1227 struct perf_event_context *ctx)
1229 mutex_unlock(&ctx->mutex);
1234 * This must be done under the ctx->lock, such as to serialize against
1235 * context_equiv(), therefore we cannot call put_ctx() since that might end up
1236 * calling scheduler related locks and ctx->lock nests inside those.
1238 static __must_check struct perf_event_context *
1239 unclone_ctx(struct perf_event_context *ctx)
1241 struct perf_event_context *parent_ctx = ctx->parent_ctx;
1243 lockdep_assert_held(&ctx->lock);
1246 ctx->parent_ctx = NULL;
1252 static u32 perf_event_pid(struct perf_event *event, struct task_struct *p)
1255 * only top level events have the pid namespace they were created in
1258 event = event->parent;
1260 return task_tgid_nr_ns(p, event->ns);
1263 static u32 perf_event_tid(struct perf_event *event, struct task_struct *p)
1266 * only top level events have the pid namespace they were created in
1269 event = event->parent;
1271 return task_pid_nr_ns(p, event->ns);
1275 * If we inherit events we want to return the parent event id
1278 static u64 primary_event_id(struct perf_event *event)
1283 id = event->parent->id;
1289 * Get the perf_event_context for a task and lock it.
1291 * This has to cope with with the fact that until it is locked,
1292 * the context could get moved to another task.
1294 static struct perf_event_context *
1295 perf_lock_task_context(struct task_struct *task, int ctxn, unsigned long *flags)
1297 struct perf_event_context *ctx;
1301 * One of the few rules of preemptible RCU is that one cannot do
1302 * rcu_read_unlock() while holding a scheduler (or nested) lock when
1303 * part of the read side critical section was irqs-enabled -- see
1304 * rcu_read_unlock_special().
1306 * Since ctx->lock nests under rq->lock we must ensure the entire read
1307 * side critical section has interrupts disabled.
1309 local_irq_save(*flags);
1311 ctx = rcu_dereference(task->perf_event_ctxp[ctxn]);
1314 * If this context is a clone of another, it might
1315 * get swapped for another underneath us by
1316 * perf_event_task_sched_out, though the
1317 * rcu_read_lock() protects us from any context
1318 * getting freed. Lock the context and check if it
1319 * got swapped before we could get the lock, and retry
1320 * if so. If we locked the right context, then it
1321 * can't get swapped on us any more.
1323 raw_spin_lock(&ctx->lock);
1324 if (ctx != rcu_dereference(task->perf_event_ctxp[ctxn])) {
1325 raw_spin_unlock(&ctx->lock);
1327 local_irq_restore(*flags);
1331 if (ctx->task == TASK_TOMBSTONE ||
1332 !atomic_inc_not_zero(&ctx->refcount)) {
1333 raw_spin_unlock(&ctx->lock);
1336 WARN_ON_ONCE(ctx->task != task);
1341 local_irq_restore(*flags);
1346 * Get the context for a task and increment its pin_count so it
1347 * can't get swapped to another task. This also increments its
1348 * reference count so that the context can't get freed.
1350 static struct perf_event_context *
1351 perf_pin_task_context(struct task_struct *task, int ctxn)
1353 struct perf_event_context *ctx;
1354 unsigned long flags;
1356 ctx = perf_lock_task_context(task, ctxn, &flags);
1359 raw_spin_unlock_irqrestore(&ctx->lock, flags);
1364 static void perf_unpin_context(struct perf_event_context *ctx)
1366 unsigned long flags;
1368 raw_spin_lock_irqsave(&ctx->lock, flags);
1370 raw_spin_unlock_irqrestore(&ctx->lock, flags);
1374 * Update the record of the current time in a context.
1376 static void update_context_time(struct perf_event_context *ctx)
1378 u64 now = perf_clock();
1380 ctx->time += now - ctx->timestamp;
1381 ctx->timestamp = now;
1384 static u64 perf_event_time(struct perf_event *event)
1386 struct perf_event_context *ctx = event->ctx;
1388 if (is_cgroup_event(event))
1389 return perf_cgroup_event_time(event);
1391 return ctx ? ctx->time : 0;
1395 * Update the total_time_enabled and total_time_running fields for a event.
1397 static void update_event_times(struct perf_event *event)
1399 struct perf_event_context *ctx = event->ctx;
1402 lockdep_assert_held(&ctx->lock);
1404 if (event->state < PERF_EVENT_STATE_INACTIVE ||
1405 event->group_leader->state < PERF_EVENT_STATE_INACTIVE)
1409 * in cgroup mode, time_enabled represents
1410 * the time the event was enabled AND active
1411 * tasks were in the monitored cgroup. This is
1412 * independent of the activity of the context as
1413 * there may be a mix of cgroup and non-cgroup events.
1415 * That is why we treat cgroup events differently
1418 if (is_cgroup_event(event))
1419 run_end = perf_cgroup_event_time(event);
1420 else if (ctx->is_active)
1421 run_end = ctx->time;
1423 run_end = event->tstamp_stopped;
1425 event->total_time_enabled = run_end - event->tstamp_enabled;
1427 if (event->state == PERF_EVENT_STATE_INACTIVE)
1428 run_end = event->tstamp_stopped;
1430 run_end = perf_event_time(event);
1432 event->total_time_running = run_end - event->tstamp_running;
1437 * Update total_time_enabled and total_time_running for all events in a group.
1439 static void update_group_times(struct perf_event *leader)
1441 struct perf_event *event;
1443 update_event_times(leader);
1444 list_for_each_entry(event, &leader->sibling_list, group_entry)
1445 update_event_times(event);
1448 static enum event_type_t get_event_type(struct perf_event *event)
1450 struct perf_event_context *ctx = event->ctx;
1451 enum event_type_t event_type;
1453 lockdep_assert_held(&ctx->lock);
1456 * It's 'group type', really, because if our group leader is
1457 * pinned, so are we.
1459 if (event->group_leader != event)
1460 event = event->group_leader;
1462 event_type = event->attr.pinned ? EVENT_PINNED : EVENT_FLEXIBLE;
1464 event_type |= EVENT_CPU;
1469 static struct list_head *
1470 ctx_group_list(struct perf_event *event, struct perf_event_context *ctx)
1472 if (event->attr.pinned)
1473 return &ctx->pinned_groups;
1475 return &ctx->flexible_groups;
1479 * Add a event from the lists for its context.
1480 * Must be called with ctx->mutex and ctx->lock held.
1483 list_add_event(struct perf_event *event, struct perf_event_context *ctx)
1485 lockdep_assert_held(&ctx->lock);
1487 WARN_ON_ONCE(event->attach_state & PERF_ATTACH_CONTEXT);
1488 event->attach_state |= PERF_ATTACH_CONTEXT;
1491 * If we're a stand alone event or group leader, we go to the context
1492 * list, group events are kept attached to the group so that
1493 * perf_group_detach can, at all times, locate all siblings.
1495 if (event->group_leader == event) {
1496 struct list_head *list;
1498 event->group_caps = event->event_caps;
1500 list = ctx_group_list(event, ctx);
1501 list_add_tail(&event->group_entry, list);
1504 list_update_cgroup_event(event, ctx, true);
1506 list_add_rcu(&event->event_entry, &ctx->event_list);
1508 if (event->attr.inherit_stat)
1515 * Initialize event state based on the perf_event_attr::disabled.
1517 static inline void perf_event__state_init(struct perf_event *event)
1519 event->state = event->attr.disabled ? PERF_EVENT_STATE_OFF :
1520 PERF_EVENT_STATE_INACTIVE;
1523 static void __perf_event_read_size(struct perf_event *event, int nr_siblings)
1525 int entry = sizeof(u64); /* value */
1529 if (event->attr.read_format & PERF_FORMAT_TOTAL_TIME_ENABLED)
1530 size += sizeof(u64);
1532 if (event->attr.read_format & PERF_FORMAT_TOTAL_TIME_RUNNING)
1533 size += sizeof(u64);
1535 if (event->attr.read_format & PERF_FORMAT_ID)
1536 entry += sizeof(u64);
1538 if (event->attr.read_format & PERF_FORMAT_GROUP) {
1540 size += sizeof(u64);
1544 event->read_size = size;
1547 static void __perf_event_header_size(struct perf_event *event, u64 sample_type)
1549 struct perf_sample_data *data;
1552 if (sample_type & PERF_SAMPLE_IP)
1553 size += sizeof(data->ip);
1555 if (sample_type & PERF_SAMPLE_ADDR)
1556 size += sizeof(data->addr);
1558 if (sample_type & PERF_SAMPLE_PERIOD)
1559 size += sizeof(data->period);
1561 if (sample_type & PERF_SAMPLE_WEIGHT)
1562 size += sizeof(data->weight);
1564 if (sample_type & PERF_SAMPLE_READ)
1565 size += event->read_size;
1567 if (sample_type & PERF_SAMPLE_DATA_SRC)
1568 size += sizeof(data->data_src.val);
1570 if (sample_type & PERF_SAMPLE_TRANSACTION)
1571 size += sizeof(data->txn);
1573 event->header_size = size;
1577 * Called at perf_event creation and when events are attached/detached from a
1580 static void perf_event__header_size(struct perf_event *event)
1582 __perf_event_read_size(event,
1583 event->group_leader->nr_siblings);
1584 __perf_event_header_size(event, event->attr.sample_type);
1587 static void perf_event__id_header_size(struct perf_event *event)
1589 struct perf_sample_data *data;
1590 u64 sample_type = event->attr.sample_type;
1593 if (sample_type & PERF_SAMPLE_TID)
1594 size += sizeof(data->tid_entry);
1596 if (sample_type & PERF_SAMPLE_TIME)
1597 size += sizeof(data->time);
1599 if (sample_type & PERF_SAMPLE_IDENTIFIER)
1600 size += sizeof(data->id);
1602 if (sample_type & PERF_SAMPLE_ID)
1603 size += sizeof(data->id);
1605 if (sample_type & PERF_SAMPLE_STREAM_ID)
1606 size += sizeof(data->stream_id);
1608 if (sample_type & PERF_SAMPLE_CPU)
1609 size += sizeof(data->cpu_entry);
1611 event->id_header_size = size;
1614 static bool perf_event_validate_size(struct perf_event *event)
1617 * The values computed here will be over-written when we actually
1620 __perf_event_read_size(event, event->group_leader->nr_siblings + 1);
1621 __perf_event_header_size(event, event->attr.sample_type & ~PERF_SAMPLE_READ);
1622 perf_event__id_header_size(event);
1625 * Sum the lot; should not exceed the 64k limit we have on records.
1626 * Conservative limit to allow for callchains and other variable fields.
1628 if (event->read_size + event->header_size +
1629 event->id_header_size + sizeof(struct perf_event_header) >= 16*1024)
1635 static void perf_group_attach(struct perf_event *event)
1637 struct perf_event *group_leader = event->group_leader, *pos;
1639 lockdep_assert_held(&event->ctx->lock);
1642 * We can have double attach due to group movement in perf_event_open.
1644 if (event->attach_state & PERF_ATTACH_GROUP)
1647 event->attach_state |= PERF_ATTACH_GROUP;
1649 if (group_leader == event)
1652 WARN_ON_ONCE(group_leader->ctx != event->ctx);
1654 group_leader->group_caps &= event->event_caps;
1656 list_add_tail(&event->group_entry, &group_leader->sibling_list);
1657 group_leader->nr_siblings++;
1659 perf_event__header_size(group_leader);
1661 list_for_each_entry(pos, &group_leader->sibling_list, group_entry)
1662 perf_event__header_size(pos);
1666 * Remove a event from the lists for its context.
1667 * Must be called with ctx->mutex and ctx->lock held.
1670 list_del_event(struct perf_event *event, struct perf_event_context *ctx)
1672 WARN_ON_ONCE(event->ctx != ctx);
1673 lockdep_assert_held(&ctx->lock);
1676 * We can have double detach due to exit/hot-unplug + close.
1678 if (!(event->attach_state & PERF_ATTACH_CONTEXT))
1681 event->attach_state &= ~PERF_ATTACH_CONTEXT;
1683 list_update_cgroup_event(event, ctx, false);
1686 if (event->attr.inherit_stat)
1689 list_del_rcu(&event->event_entry);
1691 if (event->group_leader == event)
1692 list_del_init(&event->group_entry);
1694 update_group_times(event);
1697 * If event was in error state, then keep it
1698 * that way, otherwise bogus counts will be
1699 * returned on read(). The only way to get out
1700 * of error state is by explicit re-enabling
1703 if (event->state > PERF_EVENT_STATE_OFF)
1704 event->state = PERF_EVENT_STATE_OFF;
1709 static void perf_group_detach(struct perf_event *event)
1711 struct perf_event *sibling, *tmp;
1712 struct list_head *list = NULL;
1714 lockdep_assert_held(&event->ctx->lock);
1717 * We can have double detach due to exit/hot-unplug + close.
1719 if (!(event->attach_state & PERF_ATTACH_GROUP))
1722 event->attach_state &= ~PERF_ATTACH_GROUP;
1725 * If this is a sibling, remove it from its group.
1727 if (event->group_leader != event) {
1728 list_del_init(&event->group_entry);
1729 event->group_leader->nr_siblings--;
1733 if (!list_empty(&event->group_entry))
1734 list = &event->group_entry;
1737 * If this was a group event with sibling events then
1738 * upgrade the siblings to singleton events by adding them
1739 * to whatever list we are on.
1741 list_for_each_entry_safe(sibling, tmp, &event->sibling_list, group_entry) {
1743 list_move_tail(&sibling->group_entry, list);
1744 sibling->group_leader = sibling;
1746 /* Inherit group flags from the previous leader */
1747 sibling->group_caps = event->group_caps;
1749 WARN_ON_ONCE(sibling->ctx != event->ctx);
1753 perf_event__header_size(event->group_leader);
1755 list_for_each_entry(tmp, &event->group_leader->sibling_list, group_entry)
1756 perf_event__header_size(tmp);
1759 static bool is_orphaned_event(struct perf_event *event)
1761 return event->state == PERF_EVENT_STATE_DEAD;
1764 static inline int __pmu_filter_match(struct perf_event *event)
1766 struct pmu *pmu = event->pmu;
1767 return pmu->filter_match ? pmu->filter_match(event) : 1;
1771 * Check whether we should attempt to schedule an event group based on
1772 * PMU-specific filtering. An event group can consist of HW and SW events,
1773 * potentially with a SW leader, so we must check all the filters, to
1774 * determine whether a group is schedulable:
1776 static inline int pmu_filter_match(struct perf_event *event)
1778 struct perf_event *child;
1780 if (!__pmu_filter_match(event))
1783 list_for_each_entry(child, &event->sibling_list, group_entry) {
1784 if (!__pmu_filter_match(child))
1792 event_filter_match(struct perf_event *event)
1794 return (event->cpu == -1 || event->cpu == smp_processor_id()) &&
1795 perf_cgroup_match(event) && pmu_filter_match(event);
1799 event_sched_out(struct perf_event *event,
1800 struct perf_cpu_context *cpuctx,
1801 struct perf_event_context *ctx)
1803 u64 tstamp = perf_event_time(event);
1806 WARN_ON_ONCE(event->ctx != ctx);
1807 lockdep_assert_held(&ctx->lock);
1810 * An event which could not be activated because of
1811 * filter mismatch still needs to have its timings
1812 * maintained, otherwise bogus information is return
1813 * via read() for time_enabled, time_running:
1815 if (event->state == PERF_EVENT_STATE_INACTIVE &&
1816 !event_filter_match(event)) {
1817 delta = tstamp - event->tstamp_stopped;
1818 event->tstamp_running += delta;
1819 event->tstamp_stopped = tstamp;
1822 if (event->state != PERF_EVENT_STATE_ACTIVE)
1825 perf_pmu_disable(event->pmu);
1827 event->tstamp_stopped = tstamp;
1828 event->pmu->del(event, 0);
1830 event->state = PERF_EVENT_STATE_INACTIVE;
1831 if (event->pending_disable) {
1832 event->pending_disable = 0;
1833 event->state = PERF_EVENT_STATE_OFF;
1836 if (!is_software_event(event))
1837 cpuctx->active_oncpu--;
1838 if (!--ctx->nr_active)
1839 perf_event_ctx_deactivate(ctx);
1840 if (event->attr.freq && event->attr.sample_freq)
1842 if (event->attr.exclusive || !cpuctx->active_oncpu)
1843 cpuctx->exclusive = 0;
1845 perf_pmu_enable(event->pmu);
1849 group_sched_out(struct perf_event *group_event,
1850 struct perf_cpu_context *cpuctx,
1851 struct perf_event_context *ctx)
1853 struct perf_event *event;
1854 int state = group_event->state;
1856 perf_pmu_disable(ctx->pmu);
1858 event_sched_out(group_event, cpuctx, ctx);
1861 * Schedule out siblings (if any):
1863 list_for_each_entry(event, &group_event->sibling_list, group_entry)
1864 event_sched_out(event, cpuctx, ctx);
1866 perf_pmu_enable(ctx->pmu);
1868 if (state == PERF_EVENT_STATE_ACTIVE && group_event->attr.exclusive)
1869 cpuctx->exclusive = 0;
1872 #define DETACH_GROUP 0x01UL
1875 * Cross CPU call to remove a performance event
1877 * We disable the event on the hardware level first. After that we
1878 * remove it from the context list.
1881 __perf_remove_from_context(struct perf_event *event,
1882 struct perf_cpu_context *cpuctx,
1883 struct perf_event_context *ctx,
1886 unsigned long flags = (unsigned long)info;
1888 event_sched_out(event, cpuctx, ctx);
1889 if (flags & DETACH_GROUP)
1890 perf_group_detach(event);
1891 list_del_event(event, ctx);
1893 if (!ctx->nr_events && ctx->is_active) {
1896 WARN_ON_ONCE(cpuctx->task_ctx != ctx);
1897 cpuctx->task_ctx = NULL;
1903 * Remove the event from a task's (or a CPU's) list of events.
1905 * If event->ctx is a cloned context, callers must make sure that
1906 * every task struct that event->ctx->task could possibly point to
1907 * remains valid. This is OK when called from perf_release since
1908 * that only calls us on the top-level context, which can't be a clone.
1909 * When called from perf_event_exit_task, it's OK because the
1910 * context has been detached from its task.
1912 static void perf_remove_from_context(struct perf_event *event, unsigned long flags)
1914 struct perf_event_context *ctx = event->ctx;
1916 lockdep_assert_held(&ctx->mutex);
1918 event_function_call(event, __perf_remove_from_context, (void *)flags);
1921 * The above event_function_call() can NO-OP when it hits
1922 * TASK_TOMBSTONE. In that case we must already have been detached
1923 * from the context (by perf_event_exit_event()) but the grouping
1924 * might still be in-tact.
1926 WARN_ON_ONCE(event->attach_state & PERF_ATTACH_CONTEXT);
1927 if ((flags & DETACH_GROUP) &&
1928 (event->attach_state & PERF_ATTACH_GROUP)) {
1930 * Since in that case we cannot possibly be scheduled, simply
1933 raw_spin_lock_irq(&ctx->lock);
1934 perf_group_detach(event);
1935 raw_spin_unlock_irq(&ctx->lock);
1940 * Cross CPU call to disable a performance event
1942 static void __perf_event_disable(struct perf_event *event,
1943 struct perf_cpu_context *cpuctx,
1944 struct perf_event_context *ctx,
1947 if (event->state < PERF_EVENT_STATE_INACTIVE)
1950 update_context_time(ctx);
1951 update_cgrp_time_from_event(event);
1952 update_group_times(event);
1953 if (event == event->group_leader)
1954 group_sched_out(event, cpuctx, ctx);
1956 event_sched_out(event, cpuctx, ctx);
1957 event->state = PERF_EVENT_STATE_OFF;
1963 * If event->ctx is a cloned context, callers must make sure that
1964 * every task struct that event->ctx->task could possibly point to
1965 * remains valid. This condition is satisifed when called through
1966 * perf_event_for_each_child or perf_event_for_each because they
1967 * hold the top-level event's child_mutex, so any descendant that
1968 * goes to exit will block in perf_event_exit_event().
1970 * When called from perf_pending_event it's OK because event->ctx
1971 * is the current context on this CPU and preemption is disabled,
1972 * hence we can't get into perf_event_task_sched_out for this context.
1974 static void _perf_event_disable(struct perf_event *event)
1976 struct perf_event_context *ctx = event->ctx;
1978 raw_spin_lock_irq(&ctx->lock);
1979 if (event->state <= PERF_EVENT_STATE_OFF) {
1980 raw_spin_unlock_irq(&ctx->lock);
1983 raw_spin_unlock_irq(&ctx->lock);
1985 event_function_call(event, __perf_event_disable, NULL);
1988 void perf_event_disable_local(struct perf_event *event)
1990 event_function_local(event, __perf_event_disable, NULL);
1994 * Strictly speaking kernel users cannot create groups and therefore this
1995 * interface does not need the perf_event_ctx_lock() magic.
1997 void perf_event_disable(struct perf_event *event)
1999 struct perf_event_context *ctx;
2001 ctx = perf_event_ctx_lock(event);
2002 _perf_event_disable(event);
2003 perf_event_ctx_unlock(event, ctx);
2005 EXPORT_SYMBOL_GPL(perf_event_disable);
2007 void perf_event_disable_inatomic(struct perf_event *event)
2009 event->pending_disable = 1;
2010 irq_work_queue(&event->pending);
2013 static void perf_set_shadow_time(struct perf_event *event,
2014 struct perf_event_context *ctx,
2018 * use the correct time source for the time snapshot
2020 * We could get by without this by leveraging the
2021 * fact that to get to this function, the caller
2022 * has most likely already called update_context_time()
2023 * and update_cgrp_time_xx() and thus both timestamp
2024 * are identical (or very close). Given that tstamp is,
2025 * already adjusted for cgroup, we could say that:
2026 * tstamp - ctx->timestamp
2028 * tstamp - cgrp->timestamp.
2030 * Then, in perf_output_read(), the calculation would
2031 * work with no changes because:
2032 * - event is guaranteed scheduled in
2033 * - no scheduled out in between
2034 * - thus the timestamp would be the same
2036 * But this is a bit hairy.
2038 * So instead, we have an explicit cgroup call to remain
2039 * within the time time source all along. We believe it
2040 * is cleaner and simpler to understand.
2042 if (is_cgroup_event(event))
2043 perf_cgroup_set_shadow_time(event, tstamp);
2045 event->shadow_ctx_time = tstamp - ctx->timestamp;
2048 #define MAX_INTERRUPTS (~0ULL)
2050 static void perf_log_throttle(struct perf_event *event, int enable);
2051 static void perf_log_itrace_start(struct perf_event *event);
2054 event_sched_in(struct perf_event *event,
2055 struct perf_cpu_context *cpuctx,
2056 struct perf_event_context *ctx)
2058 u64 tstamp = perf_event_time(event);
2061 lockdep_assert_held(&ctx->lock);
2063 if (event->state <= PERF_EVENT_STATE_OFF)
2066 WRITE_ONCE(event->oncpu, smp_processor_id());
2068 * Order event::oncpu write to happen before the ACTIVE state
2072 WRITE_ONCE(event->state, PERF_EVENT_STATE_ACTIVE);
2075 * Unthrottle events, since we scheduled we might have missed several
2076 * ticks already, also for a heavily scheduling task there is little
2077 * guarantee it'll get a tick in a timely manner.
2079 if (unlikely(event->hw.interrupts == MAX_INTERRUPTS)) {
2080 perf_log_throttle(event, 1);
2081 event->hw.interrupts = 0;
2085 * The new state must be visible before we turn it on in the hardware:
2089 perf_pmu_disable(event->pmu);
2091 perf_set_shadow_time(event, ctx, tstamp);
2093 perf_log_itrace_start(event);
2095 if (event->pmu->add(event, PERF_EF_START)) {
2096 event->state = PERF_EVENT_STATE_INACTIVE;
2102 event->tstamp_running += tstamp - event->tstamp_stopped;
2104 if (!is_software_event(event))
2105 cpuctx->active_oncpu++;
2106 if (!ctx->nr_active++)
2107 perf_event_ctx_activate(ctx);
2108 if (event->attr.freq && event->attr.sample_freq)
2111 if (event->attr.exclusive)
2112 cpuctx->exclusive = 1;
2115 perf_pmu_enable(event->pmu);
2121 group_sched_in(struct perf_event *group_event,
2122 struct perf_cpu_context *cpuctx,
2123 struct perf_event_context *ctx)
2125 struct perf_event *event, *partial_group = NULL;
2126 struct pmu *pmu = ctx->pmu;
2127 u64 now = ctx->time;
2128 bool simulate = false;
2130 if (group_event->state == PERF_EVENT_STATE_OFF)
2133 pmu->start_txn(pmu, PERF_PMU_TXN_ADD);
2135 if (event_sched_in(group_event, cpuctx, ctx)) {
2136 pmu->cancel_txn(pmu);
2137 perf_mux_hrtimer_restart(cpuctx);
2142 * Schedule in siblings as one group (if any):
2144 list_for_each_entry(event, &group_event->sibling_list, group_entry) {
2145 if (event_sched_in(event, cpuctx, ctx)) {
2146 partial_group = event;
2151 if (!pmu->commit_txn(pmu))
2156 * Groups can be scheduled in as one unit only, so undo any
2157 * partial group before returning:
2158 * The events up to the failed event are scheduled out normally,
2159 * tstamp_stopped will be updated.
2161 * The failed events and the remaining siblings need to have
2162 * their timings updated as if they had gone thru event_sched_in()
2163 * and event_sched_out(). This is required to get consistent timings
2164 * across the group. This also takes care of the case where the group
2165 * could never be scheduled by ensuring tstamp_stopped is set to mark
2166 * the time the event was actually stopped, such that time delta
2167 * calculation in update_event_times() is correct.
2169 list_for_each_entry(event, &group_event->sibling_list, group_entry) {
2170 if (event == partial_group)
2174 event->tstamp_running += now - event->tstamp_stopped;
2175 event->tstamp_stopped = now;
2177 event_sched_out(event, cpuctx, ctx);
2180 event_sched_out(group_event, cpuctx, ctx);
2182 pmu->cancel_txn(pmu);
2184 perf_mux_hrtimer_restart(cpuctx);
2190 * Work out whether we can put this event group on the CPU now.
2192 static int group_can_go_on(struct perf_event *event,
2193 struct perf_cpu_context *cpuctx,
2197 * Groups consisting entirely of software events can always go on.
2199 if (event->group_caps & PERF_EV_CAP_SOFTWARE)
2202 * If an exclusive group is already on, no other hardware
2205 if (cpuctx->exclusive)
2208 * If this group is exclusive and there are already
2209 * events on the CPU, it can't go on.
2211 if (event->attr.exclusive && cpuctx->active_oncpu)
2214 * Otherwise, try to add it if all previous groups were able
2221 * Complement to update_event_times(). This computes the tstamp_* values to
2222 * continue 'enabled' state from @now, and effectively discards the time
2223 * between the prior tstamp_stopped and now (as we were in the OFF state, or
2224 * just switched (context) time base).
2226 * This further assumes '@event->state == INACTIVE' (we just came from OFF) and
2227 * cannot have been scheduled in yet. And going into INACTIVE state means
2228 * '@event->tstamp_stopped = @now'.
2230 * Thus given the rules of update_event_times():
2232 * total_time_enabled = tstamp_stopped - tstamp_enabled
2233 * total_time_running = tstamp_stopped - tstamp_running
2235 * We can insert 'tstamp_stopped == now' and reverse them to compute new
2238 static void __perf_event_enable_time(struct perf_event *event, u64 now)
2240 WARN_ON_ONCE(event->state != PERF_EVENT_STATE_INACTIVE);
2242 event->tstamp_stopped = now;
2243 event->tstamp_enabled = now - event->total_time_enabled;
2244 event->tstamp_running = now - event->total_time_running;
2247 static void add_event_to_ctx(struct perf_event *event,
2248 struct perf_event_context *ctx)
2250 u64 tstamp = perf_event_time(event);
2252 list_add_event(event, ctx);
2253 perf_group_attach(event);
2255 * We can be called with event->state == STATE_OFF when we create with
2256 * .disabled = 1. In that case the IOC_ENABLE will call this function.
2258 if (event->state == PERF_EVENT_STATE_INACTIVE)
2259 __perf_event_enable_time(event, tstamp);
2262 static void ctx_sched_out(struct perf_event_context *ctx,
2263 struct perf_cpu_context *cpuctx,
2264 enum event_type_t event_type);
2266 ctx_sched_in(struct perf_event_context *ctx,
2267 struct perf_cpu_context *cpuctx,
2268 enum event_type_t event_type,
2269 struct task_struct *task);
2271 static void task_ctx_sched_out(struct perf_cpu_context *cpuctx,
2272 struct perf_event_context *ctx,
2273 enum event_type_t event_type)
2275 if (!cpuctx->task_ctx)
2278 if (WARN_ON_ONCE(ctx != cpuctx->task_ctx))
2281 ctx_sched_out(ctx, cpuctx, event_type);
2284 static void perf_event_sched_in(struct perf_cpu_context *cpuctx,
2285 struct perf_event_context *ctx,
2286 struct task_struct *task)
2288 cpu_ctx_sched_in(cpuctx, EVENT_PINNED, task);
2290 ctx_sched_in(ctx, cpuctx, EVENT_PINNED, task);
2291 cpu_ctx_sched_in(cpuctx, EVENT_FLEXIBLE, task);
2293 ctx_sched_in(ctx, cpuctx, EVENT_FLEXIBLE, task);
2297 * We want to maintain the following priority of scheduling:
2298 * - CPU pinned (EVENT_CPU | EVENT_PINNED)
2299 * - task pinned (EVENT_PINNED)
2300 * - CPU flexible (EVENT_CPU | EVENT_FLEXIBLE)
2301 * - task flexible (EVENT_FLEXIBLE).
2303 * In order to avoid unscheduling and scheduling back in everything every
2304 * time an event is added, only do it for the groups of equal priority and
2307 * This can be called after a batch operation on task events, in which case
2308 * event_type is a bit mask of the types of events involved. For CPU events,
2309 * event_type is only either EVENT_PINNED or EVENT_FLEXIBLE.
2311 static void ctx_resched(struct perf_cpu_context *cpuctx,
2312 struct perf_event_context *task_ctx,
2313 enum event_type_t event_type)
2315 enum event_type_t ctx_event_type = event_type & EVENT_ALL;
2316 bool cpu_event = !!(event_type & EVENT_CPU);
2319 * If pinned groups are involved, flexible groups also need to be
2322 if (event_type & EVENT_PINNED)
2323 event_type |= EVENT_FLEXIBLE;
2325 perf_pmu_disable(cpuctx->ctx.pmu);
2327 task_ctx_sched_out(cpuctx, task_ctx, event_type);
2330 * Decide which cpu ctx groups to schedule out based on the types
2331 * of events that caused rescheduling:
2332 * - EVENT_CPU: schedule out corresponding groups;
2333 * - EVENT_PINNED task events: schedule out EVENT_FLEXIBLE groups;
2334 * - otherwise, do nothing more.
2337 cpu_ctx_sched_out(cpuctx, ctx_event_type);
2338 else if (ctx_event_type & EVENT_PINNED)
2339 cpu_ctx_sched_out(cpuctx, EVENT_FLEXIBLE);
2341 perf_event_sched_in(cpuctx, task_ctx, current);
2342 perf_pmu_enable(cpuctx->ctx.pmu);
2346 * Cross CPU call to install and enable a performance event
2348 * Very similar to remote_function() + event_function() but cannot assume that
2349 * things like ctx->is_active and cpuctx->task_ctx are set.
2351 static int __perf_install_in_context(void *info)
2353 struct perf_event *event = info;
2354 struct perf_event_context *ctx = event->ctx;
2355 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
2356 struct perf_event_context *task_ctx = cpuctx->task_ctx;
2357 bool reprogram = true;
2360 raw_spin_lock(&cpuctx->ctx.lock);
2362 raw_spin_lock(&ctx->lock);
2365 reprogram = (ctx->task == current);
2368 * If the task is running, it must be running on this CPU,
2369 * otherwise we cannot reprogram things.
2371 * If its not running, we don't care, ctx->lock will
2372 * serialize against it becoming runnable.
2374 if (task_curr(ctx->task) && !reprogram) {
2379 WARN_ON_ONCE(reprogram && cpuctx->task_ctx && cpuctx->task_ctx != ctx);
2380 } else if (task_ctx) {
2381 raw_spin_lock(&task_ctx->lock);
2385 ctx_sched_out(ctx, cpuctx, EVENT_TIME);
2386 add_event_to_ctx(event, ctx);
2387 ctx_resched(cpuctx, task_ctx, get_event_type(event));
2389 add_event_to_ctx(event, ctx);
2393 perf_ctx_unlock(cpuctx, task_ctx);
2399 * Attach a performance event to a context.
2401 * Very similar to event_function_call, see comment there.
2404 perf_install_in_context(struct perf_event_context *ctx,
2405 struct perf_event *event,
2408 struct task_struct *task = READ_ONCE(ctx->task);
2410 lockdep_assert_held(&ctx->mutex);
2412 if (event->cpu != -1)
2416 * Ensures that if we can observe event->ctx, both the event and ctx
2417 * will be 'complete'. See perf_iterate_sb_cpu().
2419 smp_store_release(&event->ctx, ctx);
2422 cpu_function_call(cpu, __perf_install_in_context, event);
2427 * Should not happen, we validate the ctx is still alive before calling.
2429 if (WARN_ON_ONCE(task == TASK_TOMBSTONE))
2433 * Installing events is tricky because we cannot rely on ctx->is_active
2434 * to be set in case this is the nr_events 0 -> 1 transition.
2436 * Instead we use task_curr(), which tells us if the task is running.
2437 * However, since we use task_curr() outside of rq::lock, we can race
2438 * against the actual state. This means the result can be wrong.
2440 * If we get a false positive, we retry, this is harmless.
2442 * If we get a false negative, things are complicated. If we are after
2443 * perf_event_context_sched_in() ctx::lock will serialize us, and the
2444 * value must be correct. If we're before, it doesn't matter since
2445 * perf_event_context_sched_in() will program the counter.
2447 * However, this hinges on the remote context switch having observed
2448 * our task->perf_event_ctxp[] store, such that it will in fact take
2449 * ctx::lock in perf_event_context_sched_in().
2451 * We do this by task_function_call(), if the IPI fails to hit the task
2452 * we know any future context switch of task must see the
2453 * perf_event_ctpx[] store.
2457 * This smp_mb() orders the task->perf_event_ctxp[] store with the
2458 * task_cpu() load, such that if the IPI then does not find the task
2459 * running, a future context switch of that task must observe the
2464 if (!task_function_call(task, __perf_install_in_context, event))
2467 raw_spin_lock_irq(&ctx->lock);
2469 if (WARN_ON_ONCE(task == TASK_TOMBSTONE)) {
2471 * Cannot happen because we already checked above (which also
2472 * cannot happen), and we hold ctx->mutex, which serializes us
2473 * against perf_event_exit_task_context().
2475 raw_spin_unlock_irq(&ctx->lock);
2479 * If the task is not running, ctx->lock will avoid it becoming so,
2480 * thus we can safely install the event.
2482 if (task_curr(task)) {
2483 raw_spin_unlock_irq(&ctx->lock);
2486 add_event_to_ctx(event, ctx);
2487 raw_spin_unlock_irq(&ctx->lock);
2491 * Put a event into inactive state and update time fields.
2492 * Enabling the leader of a group effectively enables all
2493 * the group members that aren't explicitly disabled, so we
2494 * have to update their ->tstamp_enabled also.
2495 * Note: this works for group members as well as group leaders
2496 * since the non-leader members' sibling_lists will be empty.
2498 static void __perf_event_mark_enabled(struct perf_event *event)
2500 struct perf_event *sub;
2501 u64 tstamp = perf_event_time(event);
2503 event->state = PERF_EVENT_STATE_INACTIVE;
2504 __perf_event_enable_time(event, tstamp);
2505 list_for_each_entry(sub, &event->sibling_list, group_entry) {
2506 /* XXX should not be > INACTIVE if event isn't */
2507 if (sub->state >= PERF_EVENT_STATE_INACTIVE)
2508 __perf_event_enable_time(sub, tstamp);
2513 * Cross CPU call to enable a performance event
2515 static void __perf_event_enable(struct perf_event *event,
2516 struct perf_cpu_context *cpuctx,
2517 struct perf_event_context *ctx,
2520 struct perf_event *leader = event->group_leader;
2521 struct perf_event_context *task_ctx;
2523 if (event->state >= PERF_EVENT_STATE_INACTIVE ||
2524 event->state <= PERF_EVENT_STATE_ERROR)
2528 ctx_sched_out(ctx, cpuctx, EVENT_TIME);
2530 __perf_event_mark_enabled(event);
2532 if (!ctx->is_active)
2535 if (!event_filter_match(event)) {
2536 if (is_cgroup_event(event))
2537 perf_cgroup_defer_enabled(event);
2538 ctx_sched_in(ctx, cpuctx, EVENT_TIME, current);
2543 * If the event is in a group and isn't the group leader,
2544 * then don't put it on unless the group is on.
2546 if (leader != event && leader->state != PERF_EVENT_STATE_ACTIVE) {
2547 ctx_sched_in(ctx, cpuctx, EVENT_TIME, current);
2551 task_ctx = cpuctx->task_ctx;
2553 WARN_ON_ONCE(task_ctx != ctx);
2555 ctx_resched(cpuctx, task_ctx, get_event_type(event));
2561 * If event->ctx is a cloned context, callers must make sure that
2562 * every task struct that event->ctx->task could possibly point to
2563 * remains valid. This condition is satisfied when called through
2564 * perf_event_for_each_child or perf_event_for_each as described
2565 * for perf_event_disable.
2567 static void _perf_event_enable(struct perf_event *event)
2569 struct perf_event_context *ctx = event->ctx;
2571 raw_spin_lock_irq(&ctx->lock);
2572 if (event->state >= PERF_EVENT_STATE_INACTIVE ||
2573 event->state < PERF_EVENT_STATE_ERROR) {
2574 raw_spin_unlock_irq(&ctx->lock);
2579 * If the event is in error state, clear that first.
2581 * That way, if we see the event in error state below, we know that it
2582 * has gone back into error state, as distinct from the task having
2583 * been scheduled away before the cross-call arrived.
2585 if (event->state == PERF_EVENT_STATE_ERROR)
2586 event->state = PERF_EVENT_STATE_OFF;
2587 raw_spin_unlock_irq(&ctx->lock);
2589 event_function_call(event, __perf_event_enable, NULL);
2593 * See perf_event_disable();
2595 void perf_event_enable(struct perf_event *event)
2597 struct perf_event_context *ctx;
2599 ctx = perf_event_ctx_lock(event);
2600 _perf_event_enable(event);
2601 perf_event_ctx_unlock(event, ctx);
2603 EXPORT_SYMBOL_GPL(perf_event_enable);
2605 struct stop_event_data {
2606 struct perf_event *event;
2607 unsigned int restart;
2610 static int __perf_event_stop(void *info)
2612 struct stop_event_data *sd = info;
2613 struct perf_event *event = sd->event;
2615 /* if it's already INACTIVE, do nothing */
2616 if (READ_ONCE(event->state) != PERF_EVENT_STATE_ACTIVE)
2619 /* matches smp_wmb() in event_sched_in() */
2623 * There is a window with interrupts enabled before we get here,
2624 * so we need to check again lest we try to stop another CPU's event.
2626 if (READ_ONCE(event->oncpu) != smp_processor_id())
2629 event->pmu->stop(event, PERF_EF_UPDATE);
2632 * May race with the actual stop (through perf_pmu_output_stop()),
2633 * but it is only used for events with AUX ring buffer, and such
2634 * events will refuse to restart because of rb::aux_mmap_count==0,
2635 * see comments in perf_aux_output_begin().
2637 * Since this is happening on a event-local CPU, no trace is lost
2641 event->pmu->start(event, 0);
2646 static int perf_event_stop(struct perf_event *event, int restart)
2648 struct stop_event_data sd = {
2655 if (READ_ONCE(event->state) != PERF_EVENT_STATE_ACTIVE)
2658 /* matches smp_wmb() in event_sched_in() */
2662 * We only want to restart ACTIVE events, so if the event goes
2663 * inactive here (event->oncpu==-1), there's nothing more to do;
2664 * fall through with ret==-ENXIO.
2666 ret = cpu_function_call(READ_ONCE(event->oncpu),
2667 __perf_event_stop, &sd);
2668 } while (ret == -EAGAIN);
2674 * In order to contain the amount of racy and tricky in the address filter
2675 * configuration management, it is a two part process:
2677 * (p1) when userspace mappings change as a result of (1) or (2) or (3) below,
2678 * we update the addresses of corresponding vmas in
2679 * event::addr_filters_offs array and bump the event::addr_filters_gen;
2680 * (p2) when an event is scheduled in (pmu::add), it calls
2681 * perf_event_addr_filters_sync() which calls pmu::addr_filters_sync()
2682 * if the generation has changed since the previous call.
2684 * If (p1) happens while the event is active, we restart it to force (p2).
2686 * (1) perf_addr_filters_apply(): adjusting filters' offsets based on
2687 * pre-existing mappings, called once when new filters arrive via SET_FILTER
2689 * (2) perf_addr_filters_adjust(): adjusting filters' offsets based on newly
2690 * registered mapping, called for every new mmap(), with mm::mmap_sem down
2692 * (3) perf_event_addr_filters_exec(): clearing filters' offsets in the process
2695 void perf_event_addr_filters_sync(struct perf_event *event)
2697 struct perf_addr_filters_head *ifh = perf_event_addr_filters(event);
2699 if (!has_addr_filter(event))
2702 raw_spin_lock(&ifh->lock);
2703 if (event->addr_filters_gen != event->hw.addr_filters_gen) {
2704 event->pmu->addr_filters_sync(event);
2705 event->hw.addr_filters_gen = event->addr_filters_gen;
2707 raw_spin_unlock(&ifh->lock);
2709 EXPORT_SYMBOL_GPL(perf_event_addr_filters_sync);
2711 static int _perf_event_refresh(struct perf_event *event, int refresh)
2714 * not supported on inherited events
2716 if (event->attr.inherit || !is_sampling_event(event))
2719 atomic_add(refresh, &event->event_limit);
2720 _perf_event_enable(event);
2726 * See perf_event_disable()
2728 int perf_event_refresh(struct perf_event *event, int refresh)
2730 struct perf_event_context *ctx;
2733 ctx = perf_event_ctx_lock(event);
2734 ret = _perf_event_refresh(event, refresh);
2735 perf_event_ctx_unlock(event, ctx);
2739 EXPORT_SYMBOL_GPL(perf_event_refresh);
2741 static void ctx_sched_out(struct perf_event_context *ctx,
2742 struct perf_cpu_context *cpuctx,
2743 enum event_type_t event_type)
2745 int is_active = ctx->is_active;
2746 struct perf_event *event;
2748 lockdep_assert_held(&ctx->lock);
2750 if (likely(!ctx->nr_events)) {
2752 * See __perf_remove_from_context().
2754 WARN_ON_ONCE(ctx->is_active);
2756 WARN_ON_ONCE(cpuctx->task_ctx);
2760 ctx->is_active &= ~event_type;
2761 if (!(ctx->is_active & EVENT_ALL))
2765 WARN_ON_ONCE(cpuctx->task_ctx != ctx);
2766 if (!ctx->is_active)
2767 cpuctx->task_ctx = NULL;
2771 * Always update time if it was set; not only when it changes.
2772 * Otherwise we can 'forget' to update time for any but the last
2773 * context we sched out. For example:
2775 * ctx_sched_out(.event_type = EVENT_FLEXIBLE)
2776 * ctx_sched_out(.event_type = EVENT_PINNED)
2778 * would only update time for the pinned events.
2780 if (is_active & EVENT_TIME) {
2781 /* update (and stop) ctx time */
2782 update_context_time(ctx);
2783 update_cgrp_time_from_cpuctx(cpuctx);
2786 is_active ^= ctx->is_active; /* changed bits */
2788 if (!ctx->nr_active || !(is_active & EVENT_ALL))
2791 perf_pmu_disable(ctx->pmu);
2792 if (is_active & EVENT_PINNED) {
2793 list_for_each_entry(event, &ctx->pinned_groups, group_entry)
2794 group_sched_out(event, cpuctx, ctx);
2797 if (is_active & EVENT_FLEXIBLE) {
2798 list_for_each_entry(event, &ctx->flexible_groups, group_entry)
2799 group_sched_out(event, cpuctx, ctx);
2801 perf_pmu_enable(ctx->pmu);
2805 * Test whether two contexts are equivalent, i.e. whether they have both been
2806 * cloned from the same version of the same context.
2808 * Equivalence is measured using a generation number in the context that is
2809 * incremented on each modification to it; see unclone_ctx(), list_add_event()
2810 * and list_del_event().
2812 static int context_equiv(struct perf_event_context *ctx1,
2813 struct perf_event_context *ctx2)
2815 lockdep_assert_held(&ctx1->lock);
2816 lockdep_assert_held(&ctx2->lock);
2818 /* Pinning disables the swap optimization */
2819 if (ctx1->pin_count || ctx2->pin_count)
2822 /* If ctx1 is the parent of ctx2 */
2823 if (ctx1 == ctx2->parent_ctx && ctx1->generation == ctx2->parent_gen)
2826 /* If ctx2 is the parent of ctx1 */
2827 if (ctx1->parent_ctx == ctx2 && ctx1->parent_gen == ctx2->generation)
2831 * If ctx1 and ctx2 have the same parent; we flatten the parent
2832 * hierarchy, see perf_event_init_context().
2834 if (ctx1->parent_ctx && ctx1->parent_ctx == ctx2->parent_ctx &&
2835 ctx1->parent_gen == ctx2->parent_gen)
2842 static void __perf_event_sync_stat(struct perf_event *event,
2843 struct perf_event *next_event)
2847 if (!event->attr.inherit_stat)
2851 * Update the event value, we cannot use perf_event_read()
2852 * because we're in the middle of a context switch and have IRQs
2853 * disabled, which upsets smp_call_function_single(), however
2854 * we know the event must be on the current CPU, therefore we
2855 * don't need to use it.
2857 switch (event->state) {
2858 case PERF_EVENT_STATE_ACTIVE:
2859 event->pmu->read(event);
2862 case PERF_EVENT_STATE_INACTIVE:
2863 update_event_times(event);
2871 * In order to keep per-task stats reliable we need to flip the event
2872 * values when we flip the contexts.
2874 value = local64_read(&next_event->count);
2875 value = local64_xchg(&event->count, value);
2876 local64_set(&next_event->count, value);
2878 swap(event->total_time_enabled, next_event->total_time_enabled);
2879 swap(event->total_time_running, next_event->total_time_running);
2882 * Since we swizzled the values, update the user visible data too.
2884 perf_event_update_userpage(event);
2885 perf_event_update_userpage(next_event);
2888 static void perf_event_sync_stat(struct perf_event_context *ctx,
2889 struct perf_event_context *next_ctx)
2891 struct perf_event *event, *next_event;
2896 update_context_time(ctx);
2898 event = list_first_entry(&ctx->event_list,
2899 struct perf_event, event_entry);
2901 next_event = list_first_entry(&next_ctx->event_list,
2902 struct perf_event, event_entry);
2904 while (&event->event_entry != &ctx->event_list &&
2905 &next_event->event_entry != &next_ctx->event_list) {
2907 __perf_event_sync_stat(event, next_event);
2909 event = list_next_entry(event, event_entry);
2910 next_event = list_next_entry(next_event, event_entry);
2914 static void perf_event_context_sched_out(struct task_struct *task, int ctxn,
2915 struct task_struct *next)
2917 struct perf_event_context *ctx = task->perf_event_ctxp[ctxn];
2918 struct perf_event_context *next_ctx;
2919 struct perf_event_context *parent, *next_parent;
2920 struct perf_cpu_context *cpuctx;
2926 cpuctx = __get_cpu_context(ctx);
2927 if (!cpuctx->task_ctx)
2931 next_ctx = next->perf_event_ctxp[ctxn];
2935 parent = rcu_dereference(ctx->parent_ctx);
2936 next_parent = rcu_dereference(next_ctx->parent_ctx);
2938 /* If neither context have a parent context; they cannot be clones. */
2939 if (!parent && !next_parent)
2942 if (next_parent == ctx || next_ctx == parent || next_parent == parent) {
2944 * Looks like the two contexts are clones, so we might be
2945 * able to optimize the context switch. We lock both
2946 * contexts and check that they are clones under the
2947 * lock (including re-checking that neither has been
2948 * uncloned in the meantime). It doesn't matter which
2949 * order we take the locks because no other cpu could
2950 * be trying to lock both of these tasks.
2952 raw_spin_lock(&ctx->lock);
2953 raw_spin_lock_nested(&next_ctx->lock, SINGLE_DEPTH_NESTING);
2954 if (context_equiv(ctx, next_ctx)) {
2955 WRITE_ONCE(ctx->task, next);
2956 WRITE_ONCE(next_ctx->task, task);
2958 swap(ctx->task_ctx_data, next_ctx->task_ctx_data);
2961 * RCU_INIT_POINTER here is safe because we've not
2962 * modified the ctx and the above modification of
2963 * ctx->task and ctx->task_ctx_data are immaterial
2964 * since those values are always verified under
2965 * ctx->lock which we're now holding.
2967 RCU_INIT_POINTER(task->perf_event_ctxp[ctxn], next_ctx);
2968 RCU_INIT_POINTER(next->perf_event_ctxp[ctxn], ctx);
2972 perf_event_sync_stat(ctx, next_ctx);
2974 raw_spin_unlock(&next_ctx->lock);
2975 raw_spin_unlock(&ctx->lock);
2981 raw_spin_lock(&ctx->lock);
2982 task_ctx_sched_out(cpuctx, ctx, EVENT_ALL);
2983 raw_spin_unlock(&ctx->lock);
2987 static DEFINE_PER_CPU(struct list_head, sched_cb_list);
2989 void perf_sched_cb_dec(struct pmu *pmu)
2991 struct perf_cpu_context *cpuctx = this_cpu_ptr(pmu->pmu_cpu_context);
2993 this_cpu_dec(perf_sched_cb_usages);
2995 if (!--cpuctx->sched_cb_usage)
2996 list_del(&cpuctx->sched_cb_entry);
3000 void perf_sched_cb_inc(struct pmu *pmu)
3002 struct perf_cpu_context *cpuctx = this_cpu_ptr(pmu->pmu_cpu_context);
3004 if (!cpuctx->sched_cb_usage++)
3005 list_add(&cpuctx->sched_cb_entry, this_cpu_ptr(&sched_cb_list));
3007 this_cpu_inc(perf_sched_cb_usages);
3011 * This function provides the context switch callback to the lower code
3012 * layer. It is invoked ONLY when the context switch callback is enabled.
3014 * This callback is relevant even to per-cpu events; for example multi event
3015 * PEBS requires this to provide PID/TID information. This requires we flush
3016 * all queued PEBS records before we context switch to a new task.
3018 static void perf_pmu_sched_task(struct task_struct *prev,
3019 struct task_struct *next,
3022 struct perf_cpu_context *cpuctx;
3028 list_for_each_entry(cpuctx, this_cpu_ptr(&sched_cb_list), sched_cb_entry) {
3029 pmu = cpuctx->ctx.pmu; /* software PMUs will not have sched_task */
3031 if (WARN_ON_ONCE(!pmu->sched_task))
3034 perf_ctx_lock(cpuctx, cpuctx->task_ctx);
3035 perf_pmu_disable(pmu);
3037 pmu->sched_task(cpuctx->task_ctx, sched_in);
3039 perf_pmu_enable(pmu);
3040 perf_ctx_unlock(cpuctx, cpuctx->task_ctx);
3044 static void perf_event_switch(struct task_struct *task,
3045 struct task_struct *next_prev, bool sched_in);
3047 #define for_each_task_context_nr(ctxn) \
3048 for ((ctxn) = 0; (ctxn) < perf_nr_task_contexts; (ctxn)++)
3051 * Called from scheduler to remove the events of the current task,
3052 * with interrupts disabled.
3054 * We stop each event and update the event value in event->count.
3056 * This does not protect us against NMI, but disable()
3057 * sets the disabled bit in the control field of event _before_
3058 * accessing the event control register. If a NMI hits, then it will
3059 * not restart the event.
3061 void __perf_event_task_sched_out(struct task_struct *task,
3062 struct task_struct *next)
3066 if (__this_cpu_read(perf_sched_cb_usages))
3067 perf_pmu_sched_task(task, next, false);
3069 if (atomic_read(&nr_switch_events))
3070 perf_event_switch(task, next, false);
3072 for_each_task_context_nr(ctxn)
3073 perf_event_context_sched_out(task, ctxn, next);
3076 * if cgroup events exist on this CPU, then we need
3077 * to check if we have to switch out PMU state.
3078 * cgroup event are system-wide mode only
3080 if (atomic_read(this_cpu_ptr(&perf_cgroup_events)))
3081 perf_cgroup_sched_out(task, next);
3085 * Called with IRQs disabled
3087 static void cpu_ctx_sched_out(struct perf_cpu_context *cpuctx,
3088 enum event_type_t event_type)
3090 ctx_sched_out(&cpuctx->ctx, cpuctx, event_type);
3094 ctx_pinned_sched_in(struct perf_event_context *ctx,
3095 struct perf_cpu_context *cpuctx)
3097 struct perf_event *event;
3099 list_for_each_entry(event, &ctx->pinned_groups, group_entry) {
3100 if (event->state <= PERF_EVENT_STATE_OFF)
3102 if (!event_filter_match(event))
3105 /* may need to reset tstamp_enabled */
3106 if (is_cgroup_event(event))
3107 perf_cgroup_mark_enabled(event, ctx);
3109 if (group_can_go_on(event, cpuctx, 1))
3110 group_sched_in(event, cpuctx, ctx);
3113 * If this pinned group hasn't been scheduled,
3114 * put it in error state.
3116 if (event->state == PERF_EVENT_STATE_INACTIVE) {
3117 update_group_times(event);
3118 event->state = PERF_EVENT_STATE_ERROR;
3124 ctx_flexible_sched_in(struct perf_event_context *ctx,
3125 struct perf_cpu_context *cpuctx)
3127 struct perf_event *event;
3130 list_for_each_entry(event, &ctx->flexible_groups, group_entry) {
3131 /* Ignore events in OFF or ERROR state */
3132 if (event->state <= PERF_EVENT_STATE_OFF)
3135 * Listen to the 'cpu' scheduling filter constraint
3138 if (!event_filter_match(event))
3141 /* may need to reset tstamp_enabled */
3142 if (is_cgroup_event(event))
3143 perf_cgroup_mark_enabled(event, ctx);
3145 if (group_can_go_on(event, cpuctx, can_add_hw)) {
3146 if (group_sched_in(event, cpuctx, ctx))
3153 ctx_sched_in(struct perf_event_context *ctx,
3154 struct perf_cpu_context *cpuctx,
3155 enum event_type_t event_type,
3156 struct task_struct *task)
3158 int is_active = ctx->is_active;
3161 lockdep_assert_held(&ctx->lock);
3163 if (likely(!ctx->nr_events))
3166 ctx->is_active |= (event_type | EVENT_TIME);
3169 cpuctx->task_ctx = ctx;
3171 WARN_ON_ONCE(cpuctx->task_ctx != ctx);
3174 is_active ^= ctx->is_active; /* changed bits */
3176 if (is_active & EVENT_TIME) {
3177 /* start ctx time */
3179 ctx->timestamp = now;
3180 perf_cgroup_set_timestamp(task, ctx);
3184 * First go through the list and put on any pinned groups
3185 * in order to give them the best chance of going on.
3187 if (is_active & EVENT_PINNED)
3188 ctx_pinned_sched_in(ctx, cpuctx);
3190 /* Then walk through the lower prio flexible groups */
3191 if (is_active & EVENT_FLEXIBLE)
3192 ctx_flexible_sched_in(ctx, cpuctx);
3195 static void cpu_ctx_sched_in(struct perf_cpu_context *cpuctx,
3196 enum event_type_t event_type,
3197 struct task_struct *task)
3199 struct perf_event_context *ctx = &cpuctx->ctx;
3201 ctx_sched_in(ctx, cpuctx, event_type, task);
3204 static void perf_event_context_sched_in(struct perf_event_context *ctx,
3205 struct task_struct *task)
3207 struct perf_cpu_context *cpuctx;
3209 cpuctx = __get_cpu_context(ctx);
3210 if (cpuctx->task_ctx == ctx)
3213 perf_ctx_lock(cpuctx, ctx);
3214 perf_pmu_disable(ctx->pmu);
3216 * We want to keep the following priority order:
3217 * cpu pinned (that don't need to move), task pinned,
3218 * cpu flexible, task flexible.
3220 * However, if task's ctx is not carrying any pinned
3221 * events, no need to flip the cpuctx's events around.
3223 if (!list_empty(&ctx->pinned_groups))
3224 cpu_ctx_sched_out(cpuctx, EVENT_FLEXIBLE);
3225 perf_event_sched_in(cpuctx, ctx, task);
3226 perf_pmu_enable(ctx->pmu);
3227 perf_ctx_unlock(cpuctx, ctx);
3231 * Called from scheduler to add the events of the current task
3232 * with interrupts disabled.
3234 * We restore the event value and then enable it.
3236 * This does not protect us against NMI, but enable()
3237 * sets the enabled bit in the control field of event _before_
3238 * accessing the event control register. If a NMI hits, then it will
3239 * keep the event running.
3241 void __perf_event_task_sched_in(struct task_struct *prev,
3242 struct task_struct *task)
3244 struct perf_event_context *ctx;
3248 * If cgroup events exist on this CPU, then we need to check if we have
3249 * to switch in PMU state; cgroup event are system-wide mode only.
3251 * Since cgroup events are CPU events, we must schedule these in before
3252 * we schedule in the task events.
3254 if (atomic_read(this_cpu_ptr(&perf_cgroup_events)))
3255 perf_cgroup_sched_in(prev, task);
3257 for_each_task_context_nr(ctxn) {
3258 ctx = task->perf_event_ctxp[ctxn];
3262 perf_event_context_sched_in(ctx, task);
3265 if (atomic_read(&nr_switch_events))
3266 perf_event_switch(task, prev, true);
3268 if (__this_cpu_read(perf_sched_cb_usages))
3269 perf_pmu_sched_task(prev, task, true);
3272 static u64 perf_calculate_period(struct perf_event *event, u64 nsec, u64 count)
3274 u64 frequency = event->attr.sample_freq;
3275 u64 sec = NSEC_PER_SEC;
3276 u64 divisor, dividend;
3278 int count_fls, nsec_fls, frequency_fls, sec_fls;
3280 count_fls = fls64(count);
3281 nsec_fls = fls64(nsec);
3282 frequency_fls = fls64(frequency);
3286 * We got @count in @nsec, with a target of sample_freq HZ
3287 * the target period becomes:
3290 * period = -------------------
3291 * @nsec * sample_freq
3296 * Reduce accuracy by one bit such that @a and @b converge
3297 * to a similar magnitude.
3299 #define REDUCE_FLS(a, b) \
3301 if (a##_fls > b##_fls) { \
3311 * Reduce accuracy until either term fits in a u64, then proceed with
3312 * the other, so that finally we can do a u64/u64 division.
3314 while (count_fls + sec_fls > 64 && nsec_fls + frequency_fls > 64) {
3315 REDUCE_FLS(nsec, frequency);
3316 REDUCE_FLS(sec, count);
3319 if (count_fls + sec_fls > 64) {
3320 divisor = nsec * frequency;
3322 while (count_fls + sec_fls > 64) {
3323 REDUCE_FLS(count, sec);
3327 dividend = count * sec;
3329 dividend = count * sec;
3331 while (nsec_fls + frequency_fls > 64) {
3332 REDUCE_FLS(nsec, frequency);
3336 divisor = nsec * frequency;
3342 return div64_u64(dividend, divisor);
3345 static DEFINE_PER_CPU(int, perf_throttled_count);
3346 static DEFINE_PER_CPU(u64, perf_throttled_seq);
3348 static void perf_adjust_period(struct perf_event *event, u64 nsec, u64 count, bool disable)
3350 struct hw_perf_event *hwc = &event->hw;
3351 s64 period, sample_period;
3354 period = perf_calculate_period(event, nsec, count);
3356 delta = (s64)(period - hwc->sample_period);
3357 delta = (delta + 7) / 8; /* low pass filter */
3359 sample_period = hwc->sample_period + delta;
3364 hwc->sample_period = sample_period;
3366 if (local64_read(&hwc->period_left) > 8*sample_period) {
3368 event->pmu->stop(event, PERF_EF_UPDATE);
3370 local64_set(&hwc->period_left, 0);
3373 event->pmu->start(event, PERF_EF_RELOAD);
3378 * combine freq adjustment with unthrottling to avoid two passes over the
3379 * events. At the same time, make sure, having freq events does not change
3380 * the rate of unthrottling as that would introduce bias.
3382 static void perf_adjust_freq_unthr_context(struct perf_event_context *ctx,
3385 struct perf_event *event;
3386 struct hw_perf_event *hwc;
3387 u64 now, period = TICK_NSEC;
3391 * only need to iterate over all events iff:
3392 * - context have events in frequency mode (needs freq adjust)
3393 * - there are events to unthrottle on this cpu
3395 if (!(ctx->nr_freq || needs_unthr))
3398 raw_spin_lock(&ctx->lock);
3399 perf_pmu_disable(ctx->pmu);
3401 list_for_each_entry_rcu(event, &ctx->event_list, event_entry) {
3402 if (event->state != PERF_EVENT_STATE_ACTIVE)
3405 if (!event_filter_match(event))
3408 perf_pmu_disable(event->pmu);
3412 if (hwc->interrupts == MAX_INTERRUPTS) {
3413 hwc->interrupts = 0;
3414 perf_log_throttle(event, 1);
3415 event->pmu->start(event, 0);
3418 if (!event->attr.freq || !event->attr.sample_freq)
3422 * stop the event and update event->count
3424 event->pmu->stop(event, PERF_EF_UPDATE);
3426 now = local64_read(&event->count);
3427 delta = now - hwc->freq_count_stamp;
3428 hwc->freq_count_stamp = now;
3432 * reload only if value has changed
3433 * we have stopped the event so tell that
3434 * to perf_adjust_period() to avoid stopping it
3438 perf_adjust_period(event, period, delta, false);
3440 event->pmu->start(event, delta > 0 ? PERF_EF_RELOAD : 0);
3442 perf_pmu_enable(event->pmu);
3445 perf_pmu_enable(ctx->pmu);
3446 raw_spin_unlock(&ctx->lock);
3450 * Round-robin a context's events:
3452 static void rotate_ctx(struct perf_event_context *ctx)
3455 * Rotate the first entry last of non-pinned groups. Rotation might be
3456 * disabled by the inheritance code.
3458 if (!ctx->rotate_disable)
3459 list_rotate_left(&ctx->flexible_groups);
3462 static int perf_rotate_context(struct perf_cpu_context *cpuctx)
3464 struct perf_event_context *ctx = NULL;
3467 if (cpuctx->ctx.nr_events) {
3468 if (cpuctx->ctx.nr_events != cpuctx->ctx.nr_active)
3472 ctx = cpuctx->task_ctx;
3473 if (ctx && ctx->nr_events) {
3474 if (ctx->nr_events != ctx->nr_active)
3481 perf_ctx_lock(cpuctx, cpuctx->task_ctx);
3482 perf_pmu_disable(cpuctx->ctx.pmu);
3484 cpu_ctx_sched_out(cpuctx, EVENT_FLEXIBLE);
3486 ctx_sched_out(ctx, cpuctx, EVENT_FLEXIBLE);
3488 rotate_ctx(&cpuctx->ctx);
3492 perf_event_sched_in(cpuctx, ctx, current);
3494 perf_pmu_enable(cpuctx->ctx.pmu);
3495 perf_ctx_unlock(cpuctx, cpuctx->task_ctx);
3501 void perf_event_task_tick(void)
3503 struct list_head *head = this_cpu_ptr(&active_ctx_list);
3504 struct perf_event_context *ctx, *tmp;
3507 WARN_ON(!irqs_disabled());
3509 __this_cpu_inc(perf_throttled_seq);
3510 throttled = __this_cpu_xchg(perf_throttled_count, 0);
3511 tick_dep_clear_cpu(smp_processor_id(), TICK_DEP_BIT_PERF_EVENTS);
3513 list_for_each_entry_safe(ctx, tmp, head, active_ctx_list)
3514 perf_adjust_freq_unthr_context(ctx, throttled);
3517 static int event_enable_on_exec(struct perf_event *event,
3518 struct perf_event_context *ctx)
3520 if (!event->attr.enable_on_exec)
3523 event->attr.enable_on_exec = 0;
3524 if (event->state >= PERF_EVENT_STATE_INACTIVE)
3527 __perf_event_mark_enabled(event);
3533 * Enable all of a task's events that have been marked enable-on-exec.
3534 * This expects task == current.
3536 static void perf_event_enable_on_exec(int ctxn)
3538 struct perf_event_context *ctx, *clone_ctx = NULL;
3539 enum event_type_t event_type = 0;
3540 struct perf_cpu_context *cpuctx;
3541 struct perf_event *event;
3542 unsigned long flags;
3545 local_irq_save(flags);
3546 ctx = current->perf_event_ctxp[ctxn];
3547 if (!ctx || !ctx->nr_events)
3550 cpuctx = __get_cpu_context(ctx);
3551 perf_ctx_lock(cpuctx, ctx);
3552 ctx_sched_out(ctx, cpuctx, EVENT_TIME);
3553 list_for_each_entry(event, &ctx->event_list, event_entry) {
3554 enabled |= event_enable_on_exec(event, ctx);
3555 event_type |= get_event_type(event);
3559 * Unclone and reschedule this context if we enabled any event.
3562 clone_ctx = unclone_ctx(ctx);
3563 ctx_resched(cpuctx, ctx, event_type);
3565 ctx_sched_in(ctx, cpuctx, EVENT_TIME, current);
3567 perf_ctx_unlock(cpuctx, ctx);
3570 local_irq_restore(flags);
3576 struct perf_read_data {
3577 struct perf_event *event;
3582 static int __perf_event_read_cpu(struct perf_event *event, int event_cpu)
3584 u16 local_pkg, event_pkg;
3586 if (event->group_caps & PERF_EV_CAP_READ_ACTIVE_PKG) {
3587 int local_cpu = smp_processor_id();
3589 event_pkg = topology_physical_package_id(event_cpu);
3590 local_pkg = topology_physical_package_id(local_cpu);
3592 if (event_pkg == local_pkg)
3600 * Cross CPU call to read the hardware event
3602 static void __perf_event_read(void *info)
3604 struct perf_read_data *data = info;
3605 struct perf_event *sub, *event = data->event;
3606 struct perf_event_context *ctx = event->ctx;
3607 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
3608 struct pmu *pmu = event->pmu;
3611 * If this is a task context, we need to check whether it is
3612 * the current task context of this cpu. If not it has been
3613 * scheduled out before the smp call arrived. In that case
3614 * event->count would have been updated to a recent sample
3615 * when the event was scheduled out.
3617 if (ctx->task && cpuctx->task_ctx != ctx)
3620 raw_spin_lock(&ctx->lock);
3621 if (ctx->is_active) {
3622 update_context_time(ctx);
3623 update_cgrp_time_from_event(event);
3626 update_event_times(event);
3627 if (event->state != PERF_EVENT_STATE_ACTIVE)
3636 pmu->start_txn(pmu, PERF_PMU_TXN_READ);
3640 list_for_each_entry(sub, &event->sibling_list, group_entry) {
3641 update_event_times(sub);
3642 if (sub->state == PERF_EVENT_STATE_ACTIVE) {
3644 * Use sibling's PMU rather than @event's since
3645 * sibling could be on different (eg: software) PMU.
3647 sub->pmu->read(sub);
3651 data->ret = pmu->commit_txn(pmu);
3654 raw_spin_unlock(&ctx->lock);
3657 static inline u64 perf_event_count(struct perf_event *event)
3659 if (event->pmu->count)
3660 return event->pmu->count(event);
3662 return __perf_event_count(event);
3666 * NMI-safe method to read a local event, that is an event that
3668 * - either for the current task, or for this CPU
3669 * - does not have inherit set, for inherited task events
3670 * will not be local and we cannot read them atomically
3671 * - must not have a pmu::count method
3673 int perf_event_read_local(struct perf_event *event, u64 *value)
3675 unsigned long flags;
3679 * Disabling interrupts avoids all counter scheduling (context
3680 * switches, timer based rotation and IPIs).
3682 local_irq_save(flags);
3685 * It must not be an event with inherit set, we cannot read
3686 * all child counters from atomic context.
3688 if (event->attr.inherit) {
3694 * It must not have a pmu::count method, those are not
3697 if (event->pmu->count) {
3702 /* If this is a per-task event, it must be for current */
3703 if ((event->attach_state & PERF_ATTACH_TASK) &&
3704 event->hw.target != current) {
3709 /* If this is a per-CPU event, it must be for this CPU */
3710 if (!(event->attach_state & PERF_ATTACH_TASK) &&
3711 event->cpu != smp_processor_id()) {
3717 * If the event is currently on this CPU, its either a per-task event,
3718 * or local to this CPU. Furthermore it means its ACTIVE (otherwise
3721 if (event->oncpu == smp_processor_id())
3722 event->pmu->read(event);
3724 *value = local64_read(&event->count);
3726 local_irq_restore(flags);
3731 static int perf_event_read(struct perf_event *event, bool group)
3733 int event_cpu, ret = 0;
3736 * If event is enabled and currently active on a CPU, update the
3737 * value in the event structure:
3739 if (event->state == PERF_EVENT_STATE_ACTIVE) {
3740 struct perf_read_data data = {
3746 event_cpu = READ_ONCE(event->oncpu);
3747 if ((unsigned)event_cpu >= nr_cpu_ids)
3751 event_cpu = __perf_event_read_cpu(event, event_cpu);
3754 * Purposely ignore the smp_call_function_single() return
3757 * If event_cpu isn't a valid CPU it means the event got
3758 * scheduled out and that will have updated the event count.
3760 * Therefore, either way, we'll have an up-to-date event count
3763 (void)smp_call_function_single(event_cpu, __perf_event_read, &data, 1);
3766 } else if (event->state == PERF_EVENT_STATE_INACTIVE) {
3767 struct perf_event_context *ctx = event->ctx;
3768 unsigned long flags;
3770 raw_spin_lock_irqsave(&ctx->lock, flags);
3772 * may read while context is not active
3773 * (e.g., thread is blocked), in that case
3774 * we cannot update context time
3776 if (ctx->is_active) {
3777 update_context_time(ctx);
3778 update_cgrp_time_from_event(event);
3781 update_group_times(event);
3783 update_event_times(event);
3784 raw_spin_unlock_irqrestore(&ctx->lock, flags);
3791 * Initialize the perf_event context in a task_struct:
3793 static void __perf_event_init_context(struct perf_event_context *ctx)
3795 raw_spin_lock_init(&ctx->lock);
3796 mutex_init(&ctx->mutex);
3797 INIT_LIST_HEAD(&ctx->active_ctx_list);
3798 INIT_LIST_HEAD(&ctx->pinned_groups);
3799 INIT_LIST_HEAD(&ctx->flexible_groups);
3800 INIT_LIST_HEAD(&ctx->event_list);
3801 atomic_set(&ctx->refcount, 1);
3804 static struct perf_event_context *
3805 alloc_perf_context(struct pmu *pmu, struct task_struct *task)
3807 struct perf_event_context *ctx;
3809 ctx = kzalloc(sizeof(struct perf_event_context), GFP_KERNEL);
3813 __perf_event_init_context(ctx);
3816 get_task_struct(task);
3823 static struct task_struct *
3824 find_lively_task_by_vpid(pid_t vpid)
3826 struct task_struct *task;
3832 task = find_task_by_vpid(vpid);
3834 get_task_struct(task);
3838 return ERR_PTR(-ESRCH);
3844 * Returns a matching context with refcount and pincount.
3846 static struct perf_event_context *
3847 find_get_context(struct pmu *pmu, struct task_struct *task,
3848 struct perf_event *event)
3850 struct perf_event_context *ctx, *clone_ctx = NULL;
3851 struct perf_cpu_context *cpuctx;
3852 void *task_ctx_data = NULL;
3853 unsigned long flags;
3855 int cpu = event->cpu;
3858 /* Must be root to operate on a CPU event: */
3859 if (perf_paranoid_cpu() && !capable(CAP_SYS_ADMIN))
3860 return ERR_PTR(-EACCES);
3862 cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
3871 ctxn = pmu->task_ctx_nr;
3875 if (event->attach_state & PERF_ATTACH_TASK_DATA) {
3876 task_ctx_data = kzalloc(pmu->task_ctx_size, GFP_KERNEL);
3877 if (!task_ctx_data) {
3884 ctx = perf_lock_task_context(task, ctxn, &flags);
3886 clone_ctx = unclone_ctx(ctx);
3889 if (task_ctx_data && !ctx->task_ctx_data) {
3890 ctx->task_ctx_data = task_ctx_data;
3891 task_ctx_data = NULL;
3893 raw_spin_unlock_irqrestore(&ctx->lock, flags);
3898 ctx = alloc_perf_context(pmu, task);
3903 if (task_ctx_data) {
3904 ctx->task_ctx_data = task_ctx_data;
3905 task_ctx_data = NULL;
3909 mutex_lock(&task->perf_event_mutex);
3911 * If it has already passed perf_event_exit_task().
3912 * we must see PF_EXITING, it takes this mutex too.
3914 if (task->flags & PF_EXITING)
3916 else if (task->perf_event_ctxp[ctxn])
3921 rcu_assign_pointer(task->perf_event_ctxp[ctxn], ctx);
3923 mutex_unlock(&task->perf_event_mutex);
3925 if (unlikely(err)) {
3934 kfree(task_ctx_data);
3938 kfree(task_ctx_data);
3939 return ERR_PTR(err);
3942 static void perf_event_free_filter(struct perf_event *event);
3943 static void perf_event_free_bpf_prog(struct perf_event *event);
3945 static void free_event_rcu(struct rcu_head *head)
3947 struct perf_event *event;
3949 event = container_of(head, struct perf_event, rcu_head);
3951 put_pid_ns(event->ns);
3952 perf_event_free_filter(event);
3956 static void ring_buffer_attach(struct perf_event *event,
3957 struct ring_buffer *rb);
3959 static void detach_sb_event(struct perf_event *event)
3961 struct pmu_event_list *pel = per_cpu_ptr(&pmu_sb_events, event->cpu);
3963 raw_spin_lock(&pel->lock);
3964 list_del_rcu(&event->sb_list);
3965 raw_spin_unlock(&pel->lock);
3968 static bool is_sb_event(struct perf_event *event)
3970 struct perf_event_attr *attr = &event->attr;
3975 if (event->attach_state & PERF_ATTACH_TASK)
3978 if (attr->mmap || attr->mmap_data || attr->mmap2 ||
3979 attr->comm || attr->comm_exec ||
3981 attr->context_switch)
3986 static void unaccount_pmu_sb_event(struct perf_event *event)
3988 if (is_sb_event(event))
3989 detach_sb_event(event);
3992 static void unaccount_event_cpu(struct perf_event *event, int cpu)
3997 if (is_cgroup_event(event))
3998 atomic_dec(&per_cpu(perf_cgroup_events, cpu));
4001 #ifdef CONFIG_NO_HZ_FULL
4002 static DEFINE_SPINLOCK(nr_freq_lock);
4005 static void unaccount_freq_event_nohz(void)
4007 #ifdef CONFIG_NO_HZ_FULL
4008 spin_lock(&nr_freq_lock);
4009 if (atomic_dec_and_test(&nr_freq_events))
4010 tick_nohz_dep_clear(TICK_DEP_BIT_PERF_EVENTS);
4011 spin_unlock(&nr_freq_lock);
4015 static void unaccount_freq_event(void)
4017 if (tick_nohz_full_enabled())
4018 unaccount_freq_event_nohz();
4020 atomic_dec(&nr_freq_events);
4023 static void unaccount_event(struct perf_event *event)
4030 if (event->attach_state & PERF_ATTACH_TASK)
4032 if (event->attr.mmap || event->attr.mmap_data)
4033 atomic_dec(&nr_mmap_events);
4034 if (event->attr.comm)
4035 atomic_dec(&nr_comm_events);
4036 if (event->attr.namespaces)
4037 atomic_dec(&nr_namespaces_events);
4038 if (event->attr.task)
4039 atomic_dec(&nr_task_events);
4040 if (event->attr.freq)
4041 unaccount_freq_event();
4042 if (event->attr.context_switch) {
4044 atomic_dec(&nr_switch_events);
4046 if (is_cgroup_event(event))
4048 if (has_branch_stack(event))
4052 if (!atomic_add_unless(&perf_sched_count, -1, 1))
4053 schedule_delayed_work(&perf_sched_work, HZ);
4056 unaccount_event_cpu(event, event->cpu);
4058 unaccount_pmu_sb_event(event);
4061 static void perf_sched_delayed(struct work_struct *work)
4063 mutex_lock(&perf_sched_mutex);
4064 if (atomic_dec_and_test(&perf_sched_count))
4065 static_branch_disable(&perf_sched_events);
4066 mutex_unlock(&perf_sched_mutex);
4070 * The following implement mutual exclusion of events on "exclusive" pmus
4071 * (PERF_PMU_CAP_EXCLUSIVE). Such pmus can only have one event scheduled
4072 * at a time, so we disallow creating events that might conflict, namely:
4074 * 1) cpu-wide events in the presence of per-task events,
4075 * 2) per-task events in the presence of cpu-wide events,
4076 * 3) two matching events on the same context.
4078 * The former two cases are handled in the allocation path (perf_event_alloc(),
4079 * _free_event()), the latter -- before the first perf_install_in_context().
4081 static int exclusive_event_init(struct perf_event *event)
4083 struct pmu *pmu = event->pmu;
4085 if (!(pmu->capabilities & PERF_PMU_CAP_EXCLUSIVE))
4089 * Prevent co-existence of per-task and cpu-wide events on the
4090 * same exclusive pmu.
4092 * Negative pmu::exclusive_cnt means there are cpu-wide
4093 * events on this "exclusive" pmu, positive means there are
4096 * Since this is called in perf_event_alloc() path, event::ctx
4097 * doesn't exist yet; it is, however, safe to use PERF_ATTACH_TASK
4098 * to mean "per-task event", because unlike other attach states it
4099 * never gets cleared.
4101 if (event->attach_state & PERF_ATTACH_TASK) {
4102 if (!atomic_inc_unless_negative(&pmu->exclusive_cnt))
4105 if (!atomic_dec_unless_positive(&pmu->exclusive_cnt))
4112 static void exclusive_event_destroy(struct perf_event *event)
4114 struct pmu *pmu = event->pmu;
4116 if (!(pmu->capabilities & PERF_PMU_CAP_EXCLUSIVE))
4119 /* see comment in exclusive_event_init() */
4120 if (event->attach_state & PERF_ATTACH_TASK)
4121 atomic_dec(&pmu->exclusive_cnt);
4123 atomic_inc(&pmu->exclusive_cnt);
4126 static bool exclusive_event_match(struct perf_event *e1, struct perf_event *e2)
4128 if ((e1->pmu == e2->pmu) &&
4129 (e1->cpu == e2->cpu ||
4136 /* Called under the same ctx::mutex as perf_install_in_context() */
4137 static bool exclusive_event_installable(struct perf_event *event,
4138 struct perf_event_context *ctx)
4140 struct perf_event *iter_event;
4141 struct pmu *pmu = event->pmu;
4143 if (!(pmu->capabilities & PERF_PMU_CAP_EXCLUSIVE))
4146 list_for_each_entry(iter_event, &ctx->event_list, event_entry) {
4147 if (exclusive_event_match(iter_event, event))
4154 static void perf_addr_filters_splice(struct perf_event *event,
4155 struct list_head *head);
4157 static void _free_event(struct perf_event *event)
4159 irq_work_sync(&event->pending);
4161 unaccount_event(event);
4165 * Can happen when we close an event with re-directed output.
4167 * Since we have a 0 refcount, perf_mmap_close() will skip
4168 * over us; possibly making our ring_buffer_put() the last.
4170 mutex_lock(&event->mmap_mutex);
4171 ring_buffer_attach(event, NULL);
4172 mutex_unlock(&event->mmap_mutex);
4175 if (is_cgroup_event(event))
4176 perf_detach_cgroup(event);
4178 if (!event->parent) {
4179 if (event->attr.sample_type & PERF_SAMPLE_CALLCHAIN)
4180 put_callchain_buffers();
4183 perf_event_free_bpf_prog(event);
4184 perf_addr_filters_splice(event, NULL);
4185 kfree(event->addr_filters_offs);
4188 event->destroy(event);
4191 put_ctx(event->ctx);
4193 exclusive_event_destroy(event);
4194 module_put(event->pmu->module);
4196 call_rcu(&event->rcu_head, free_event_rcu);
4200 * Used to free events which have a known refcount of 1, such as in error paths
4201 * where the event isn't exposed yet and inherited events.
4203 static void free_event(struct perf_event *event)
4205 if (WARN(atomic_long_cmpxchg(&event->refcount, 1, 0) != 1,
4206 "unexpected event refcount: %ld; ptr=%p\n",
4207 atomic_long_read(&event->refcount), event)) {
4208 /* leak to avoid use-after-free */
4216 * Remove user event from the owner task.
4218 static void perf_remove_from_owner(struct perf_event *event)
4220 struct task_struct *owner;
4224 * Matches the smp_store_release() in perf_event_exit_task(). If we
4225 * observe !owner it means the list deletion is complete and we can
4226 * indeed free this event, otherwise we need to serialize on
4227 * owner->perf_event_mutex.
4229 owner = lockless_dereference(event->owner);
4232 * Since delayed_put_task_struct() also drops the last
4233 * task reference we can safely take a new reference
4234 * while holding the rcu_read_lock().
4236 get_task_struct(owner);
4242 * If we're here through perf_event_exit_task() we're already
4243 * holding ctx->mutex which would be an inversion wrt. the
4244 * normal lock order.
4246 * However we can safely take this lock because its the child
4249 mutex_lock_nested(&owner->perf_event_mutex, SINGLE_DEPTH_NESTING);
4252 * We have to re-check the event->owner field, if it is cleared
4253 * we raced with perf_event_exit_task(), acquiring the mutex
4254 * ensured they're done, and we can proceed with freeing the
4258 list_del_init(&event->owner_entry);
4259 smp_store_release(&event->owner, NULL);
4261 mutex_unlock(&owner->perf_event_mutex);
4262 put_task_struct(owner);
4266 static void put_event(struct perf_event *event)
4268 if (!atomic_long_dec_and_test(&event->refcount))
4275 * Kill an event dead; while event:refcount will preserve the event
4276 * object, it will not preserve its functionality. Once the last 'user'
4277 * gives up the object, we'll destroy the thing.
4279 int perf_event_release_kernel(struct perf_event *event)
4281 struct perf_event_context *ctx = event->ctx;
4282 struct perf_event *child, *tmp;
4285 * If we got here through err_file: fput(event_file); we will not have
4286 * attached to a context yet.
4289 WARN_ON_ONCE(event->attach_state &
4290 (PERF_ATTACH_CONTEXT|PERF_ATTACH_GROUP));
4294 if (!is_kernel_event(event))
4295 perf_remove_from_owner(event);
4297 ctx = perf_event_ctx_lock(event);
4298 WARN_ON_ONCE(ctx->parent_ctx);
4299 perf_remove_from_context(event, DETACH_GROUP);
4301 raw_spin_lock_irq(&ctx->lock);
4303 * Mark this event as STATE_DEAD, there is no external reference to it
4306 * Anybody acquiring event->child_mutex after the below loop _must_
4307 * also see this, most importantly inherit_event() which will avoid
4308 * placing more children on the list.
4310 * Thus this guarantees that we will in fact observe and kill _ALL_
4313 event->state = PERF_EVENT_STATE_DEAD;
4314 raw_spin_unlock_irq(&ctx->lock);
4316 perf_event_ctx_unlock(event, ctx);
4319 mutex_lock(&event->child_mutex);
4320 list_for_each_entry(child, &event->child_list, child_list) {
4323 * Cannot change, child events are not migrated, see the
4324 * comment with perf_event_ctx_lock_nested().
4326 ctx = lockless_dereference(child->ctx);
4328 * Since child_mutex nests inside ctx::mutex, we must jump
4329 * through hoops. We start by grabbing a reference on the ctx.
4331 * Since the event cannot get freed while we hold the
4332 * child_mutex, the context must also exist and have a !0
4338 * Now that we have a ctx ref, we can drop child_mutex, and
4339 * acquire ctx::mutex without fear of it going away. Then we
4340 * can re-acquire child_mutex.
4342 mutex_unlock(&event->child_mutex);
4343 mutex_lock(&ctx->mutex);
4344 mutex_lock(&event->child_mutex);
4347 * Now that we hold ctx::mutex and child_mutex, revalidate our
4348 * state, if child is still the first entry, it didn't get freed
4349 * and we can continue doing so.
4351 tmp = list_first_entry_or_null(&event->child_list,
4352 struct perf_event, child_list);
4354 perf_remove_from_context(child, DETACH_GROUP);
4355 list_del(&child->child_list);
4358 * This matches the refcount bump in inherit_event();
4359 * this can't be the last reference.
4364 mutex_unlock(&event->child_mutex);
4365 mutex_unlock(&ctx->mutex);
4369 mutex_unlock(&event->child_mutex);
4372 put_event(event); /* Must be the 'last' reference */
4375 EXPORT_SYMBOL_GPL(perf_event_release_kernel);
4378 * Called when the last reference to the file is gone.
4380 static int perf_release(struct inode *inode, struct file *file)
4382 perf_event_release_kernel(file->private_data);
4386 u64 perf_event_read_value(struct perf_event *event, u64 *enabled, u64 *running)
4388 struct perf_event *child;
4394 mutex_lock(&event->child_mutex);
4396 (void)perf_event_read(event, false);
4397 total += perf_event_count(event);
4399 *enabled += event->total_time_enabled +
4400 atomic64_read(&event->child_total_time_enabled);
4401 *running += event->total_time_running +
4402 atomic64_read(&event->child_total_time_running);
4404 list_for_each_entry(child, &event->child_list, child_list) {
4405 (void)perf_event_read(child, false);
4406 total += perf_event_count(child);
4407 *enabled += child->total_time_enabled;
4408 *running += child->total_time_running;
4410 mutex_unlock(&event->child_mutex);
4414 EXPORT_SYMBOL_GPL(perf_event_read_value);
4416 static int __perf_read_group_add(struct perf_event *leader,
4417 u64 read_format, u64 *values)
4419 struct perf_event_context *ctx = leader->ctx;
4420 struct perf_event *sub;
4421 unsigned long flags;
4422 int n = 1; /* skip @nr */
4425 ret = perf_event_read(leader, true);
4430 * Since we co-schedule groups, {enabled,running} times of siblings
4431 * will be identical to those of the leader, so we only publish one
4434 if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED) {
4435 values[n++] += leader->total_time_enabled +
4436 atomic64_read(&leader->child_total_time_enabled);
4439 if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING) {
4440 values[n++] += leader->total_time_running +
4441 atomic64_read(&leader->child_total_time_running);
4445 * Write {count,id} tuples for every sibling.
4447 values[n++] += perf_event_count(leader);
4448 if (read_format & PERF_FORMAT_ID)
4449 values[n++] = primary_event_id(leader);
4451 raw_spin_lock_irqsave(&ctx->lock, flags);
4453 list_for_each_entry(sub, &leader->sibling_list, group_entry) {
4454 values[n++] += perf_event_count(sub);
4455 if (read_format & PERF_FORMAT_ID)
4456 values[n++] = primary_event_id(sub);
4459 raw_spin_unlock_irqrestore(&ctx->lock, flags);
4463 static int perf_read_group(struct perf_event *event,
4464 u64 read_format, char __user *buf)
4466 struct perf_event *leader = event->group_leader, *child;
4467 struct perf_event_context *ctx = leader->ctx;
4471 lockdep_assert_held(&ctx->mutex);
4473 values = kzalloc(event->read_size, GFP_KERNEL);
4477 values[0] = 1 + leader->nr_siblings;
4480 * By locking the child_mutex of the leader we effectively
4481 * lock the child list of all siblings.. XXX explain how.
4483 mutex_lock(&leader->child_mutex);
4485 ret = __perf_read_group_add(leader, read_format, values);
4489 list_for_each_entry(child, &leader->child_list, child_list) {
4490 ret = __perf_read_group_add(child, read_format, values);
4495 mutex_unlock(&leader->child_mutex);
4497 ret = event->read_size;
4498 if (copy_to_user(buf, values, event->read_size))
4503 mutex_unlock(&leader->child_mutex);
4509 static int perf_read_one(struct perf_event *event,
4510 u64 read_format, char __user *buf)
4512 u64 enabled, running;
4516 values[n++] = perf_event_read_value(event, &enabled, &running);
4517 if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED)
4518 values[n++] = enabled;
4519 if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING)
4520 values[n++] = running;
4521 if (read_format & PERF_FORMAT_ID)
4522 values[n++] = primary_event_id(event);
4524 if (copy_to_user(buf, values, n * sizeof(u64)))
4527 return n * sizeof(u64);
4530 static bool is_event_hup(struct perf_event *event)
4534 if (event->state > PERF_EVENT_STATE_EXIT)
4537 mutex_lock(&event->child_mutex);
4538 no_children = list_empty(&event->child_list);
4539 mutex_unlock(&event->child_mutex);
4544 * Read the performance event - simple non blocking version for now
4547 __perf_read(struct perf_event *event, char __user *buf, size_t count)
4549 u64 read_format = event->attr.read_format;
4553 * Return end-of-file for a read on a event that is in
4554 * error state (i.e. because it was pinned but it couldn't be
4555 * scheduled on to the CPU at some point).
4557 if (event->state == PERF_EVENT_STATE_ERROR)
4560 if (count < event->read_size)
4563 WARN_ON_ONCE(event->ctx->parent_ctx);
4564 if (read_format & PERF_FORMAT_GROUP)
4565 ret = perf_read_group(event, read_format, buf);
4567 ret = perf_read_one(event, read_format, buf);
4573 perf_read(struct file *file, char __user *buf, size_t count, loff_t *ppos)
4575 struct perf_event *event = file->private_data;
4576 struct perf_event_context *ctx;
4579 ctx = perf_event_ctx_lock(event);
4580 ret = __perf_read(event, buf, count);
4581 perf_event_ctx_unlock(event, ctx);
4586 static unsigned int perf_poll(struct file *file, poll_table *wait)
4588 struct perf_event *event = file->private_data;
4589 struct ring_buffer *rb;
4590 unsigned int events = POLLHUP;
4592 poll_wait(file, &event->waitq, wait);
4594 if (is_event_hup(event))
4598 * Pin the event->rb by taking event->mmap_mutex; otherwise
4599 * perf_event_set_output() can swizzle our rb and make us miss wakeups.
4601 mutex_lock(&event->mmap_mutex);
4604 events = atomic_xchg(&rb->poll, 0);
4605 mutex_unlock(&event->mmap_mutex);
4609 static void _perf_event_reset(struct perf_event *event)
4611 (void)perf_event_read(event, false);
4612 local64_set(&event->count, 0);
4613 perf_event_update_userpage(event);
4617 * Holding the top-level event's child_mutex means that any
4618 * descendant process that has inherited this event will block
4619 * in perf_event_exit_event() if it goes to exit, thus satisfying the
4620 * task existence requirements of perf_event_enable/disable.
4622 static void perf_event_for_each_child(struct perf_event *event,
4623 void (*func)(struct perf_event *))
4625 struct perf_event *child;
4627 WARN_ON_ONCE(event->ctx->parent_ctx);
4629 mutex_lock(&event->child_mutex);
4631 list_for_each_entry(child, &event->child_list, child_list)
4633 mutex_unlock(&event->child_mutex);
4636 static void perf_event_for_each(struct perf_event *event,
4637 void (*func)(struct perf_event *))
4639 struct perf_event_context *ctx = event->ctx;
4640 struct perf_event *sibling;
4642 lockdep_assert_held(&ctx->mutex);
4644 event = event->group_leader;
4646 perf_event_for_each_child(event, func);
4647 list_for_each_entry(sibling, &event->sibling_list, group_entry)
4648 perf_event_for_each_child(sibling, func);
4651 static void __perf_event_period(struct perf_event *event,
4652 struct perf_cpu_context *cpuctx,
4653 struct perf_event_context *ctx,
4656 u64 value = *((u64 *)info);
4659 if (event->attr.freq) {
4660 event->attr.sample_freq = value;
4662 event->attr.sample_period = value;
4663 event->hw.sample_period = value;
4666 active = (event->state == PERF_EVENT_STATE_ACTIVE);
4668 perf_pmu_disable(ctx->pmu);
4670 * We could be throttled; unthrottle now to avoid the tick
4671 * trying to unthrottle while we already re-started the event.
4673 if (event->hw.interrupts == MAX_INTERRUPTS) {
4674 event->hw.interrupts = 0;
4675 perf_log_throttle(event, 1);
4677 event->pmu->stop(event, PERF_EF_UPDATE);
4680 local64_set(&event->hw.period_left, 0);
4683 event->pmu->start(event, PERF_EF_RELOAD);
4684 perf_pmu_enable(ctx->pmu);
4688 static int perf_event_period(struct perf_event *event, u64 __user *arg)
4692 if (!is_sampling_event(event))
4695 if (copy_from_user(&value, arg, sizeof(value)))
4701 if (event->attr.freq && value > sysctl_perf_event_sample_rate)
4704 event_function_call(event, __perf_event_period, &value);
4709 static const struct file_operations perf_fops;
4711 static inline int perf_fget_light(int fd, struct fd *p)
4713 struct fd f = fdget(fd);
4717 if (f.file->f_op != &perf_fops) {
4725 static int perf_event_set_output(struct perf_event *event,
4726 struct perf_event *output_event);
4727 static int perf_event_set_filter(struct perf_event *event, void __user *arg);
4728 static int perf_event_set_bpf_prog(struct perf_event *event, u32 prog_fd);
4730 static long _perf_ioctl(struct perf_event *event, unsigned int cmd, unsigned long arg)
4732 void (*func)(struct perf_event *);
4736 case PERF_EVENT_IOC_ENABLE:
4737 func = _perf_event_enable;
4739 case PERF_EVENT_IOC_DISABLE:
4740 func = _perf_event_disable;
4742 case PERF_EVENT_IOC_RESET:
4743 func = _perf_event_reset;
4746 case PERF_EVENT_IOC_REFRESH:
4747 return _perf_event_refresh(event, arg);
4749 case PERF_EVENT_IOC_PERIOD:
4750 return perf_event_period(event, (u64 __user *)arg);
4752 case PERF_EVENT_IOC_ID:
4754 u64 id = primary_event_id(event);
4756 if (copy_to_user((void __user *)arg, &id, sizeof(id)))
4761 case PERF_EVENT_IOC_SET_OUTPUT:
4765 struct perf_event *output_event;
4767 ret = perf_fget_light(arg, &output);
4770 output_event = output.file->private_data;
4771 ret = perf_event_set_output(event, output_event);
4774 ret = perf_event_set_output(event, NULL);
4779 case PERF_EVENT_IOC_SET_FILTER:
4780 return perf_event_set_filter(event, (void __user *)arg);
4782 case PERF_EVENT_IOC_SET_BPF:
4783 return perf_event_set_bpf_prog(event, arg);
4785 case PERF_EVENT_IOC_PAUSE_OUTPUT: {
4786 struct ring_buffer *rb;
4789 rb = rcu_dereference(event->rb);
4790 if (!rb || !rb->nr_pages) {
4794 rb_toggle_paused(rb, !!arg);
4802 if (flags & PERF_IOC_FLAG_GROUP)
4803 perf_event_for_each(event, func);
4805 perf_event_for_each_child(event, func);
4810 static long perf_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
4812 struct perf_event *event = file->private_data;
4813 struct perf_event_context *ctx;
4816 ctx = perf_event_ctx_lock(event);
4817 ret = _perf_ioctl(event, cmd, arg);
4818 perf_event_ctx_unlock(event, ctx);
4823 #ifdef CONFIG_COMPAT
4824 static long perf_compat_ioctl(struct file *file, unsigned int cmd,
4827 switch (_IOC_NR(cmd)) {
4828 case _IOC_NR(PERF_EVENT_IOC_SET_FILTER):
4829 case _IOC_NR(PERF_EVENT_IOC_ID):
4830 /* Fix up pointer size (usually 4 -> 8 in 32-on-64-bit case */
4831 if (_IOC_SIZE(cmd) == sizeof(compat_uptr_t)) {
4832 cmd &= ~IOCSIZE_MASK;
4833 cmd |= sizeof(void *) << IOCSIZE_SHIFT;
4837 return perf_ioctl(file, cmd, arg);
4840 # define perf_compat_ioctl NULL
4843 int perf_event_task_enable(void)
4845 struct perf_event_context *ctx;
4846 struct perf_event *event;
4848 mutex_lock(¤t->perf_event_mutex);
4849 list_for_each_entry(event, ¤t->perf_event_list, owner_entry) {
4850 ctx = perf_event_ctx_lock(event);
4851 perf_event_for_each_child(event, _perf_event_enable);
4852 perf_event_ctx_unlock(event, ctx);
4854 mutex_unlock(¤t->perf_event_mutex);
4859 int perf_event_task_disable(void)
4861 struct perf_event_context *ctx;
4862 struct perf_event *event;
4864 mutex_lock(¤t->perf_event_mutex);
4865 list_for_each_entry(event, ¤t->perf_event_list, owner_entry) {
4866 ctx = perf_event_ctx_lock(event);
4867 perf_event_for_each_child(event, _perf_event_disable);
4868 perf_event_ctx_unlock(event, ctx);
4870 mutex_unlock(¤t->perf_event_mutex);
4875 static int perf_event_index(struct perf_event *event)
4877 if (event->hw.state & PERF_HES_STOPPED)
4880 if (event->state != PERF_EVENT_STATE_ACTIVE)
4883 return event->pmu->event_idx(event);
4886 static void calc_timer_values(struct perf_event *event,
4893 *now = perf_clock();
4894 ctx_time = event->shadow_ctx_time + *now;
4895 *enabled = ctx_time - event->tstamp_enabled;
4896 *running = ctx_time - event->tstamp_running;
4899 static void perf_event_init_userpage(struct perf_event *event)
4901 struct perf_event_mmap_page *userpg;
4902 struct ring_buffer *rb;
4905 rb = rcu_dereference(event->rb);
4909 userpg = rb->user_page;
4911 /* Allow new userspace to detect that bit 0 is deprecated */
4912 userpg->cap_bit0_is_deprecated = 1;
4913 userpg->size = offsetof(struct perf_event_mmap_page, __reserved);
4914 userpg->data_offset = PAGE_SIZE;
4915 userpg->data_size = perf_data_size(rb);
4921 void __weak arch_perf_update_userpage(
4922 struct perf_event *event, struct perf_event_mmap_page *userpg, u64 now)
4927 * Callers need to ensure there can be no nesting of this function, otherwise
4928 * the seqlock logic goes bad. We can not serialize this because the arch
4929 * code calls this from NMI context.
4931 void perf_event_update_userpage(struct perf_event *event)
4933 struct perf_event_mmap_page *userpg;
4934 struct ring_buffer *rb;
4935 u64 enabled, running, now;
4938 rb = rcu_dereference(event->rb);
4943 * compute total_time_enabled, total_time_running
4944 * based on snapshot values taken when the event
4945 * was last scheduled in.
4947 * we cannot simply called update_context_time()
4948 * because of locking issue as we can be called in
4951 calc_timer_values(event, &now, &enabled, &running);
4953 userpg = rb->user_page;
4955 * Disable preemption so as to not let the corresponding user-space
4956 * spin too long if we get preempted.
4961 userpg->index = perf_event_index(event);
4962 userpg->offset = perf_event_count(event);
4964 userpg->offset -= local64_read(&event->hw.prev_count);
4966 userpg->time_enabled = enabled +
4967 atomic64_read(&event->child_total_time_enabled);
4969 userpg->time_running = running +
4970 atomic64_read(&event->child_total_time_running);
4972 arch_perf_update_userpage(event, userpg, now);
4981 static int perf_mmap_fault(struct vm_fault *vmf)
4983 struct perf_event *event = vmf->vma->vm_file->private_data;
4984 struct ring_buffer *rb;
4985 int ret = VM_FAULT_SIGBUS;
4987 if (vmf->flags & FAULT_FLAG_MKWRITE) {
4988 if (vmf->pgoff == 0)
4994 rb = rcu_dereference(event->rb);
4998 if (vmf->pgoff && (vmf->flags & FAULT_FLAG_WRITE))
5001 vmf->page = perf_mmap_to_page(rb, vmf->pgoff);
5005 get_page(vmf->page);
5006 vmf->page->mapping = vmf->vma->vm_file->f_mapping;
5007 vmf->page->index = vmf->pgoff;
5016 static void ring_buffer_attach(struct perf_event *event,
5017 struct ring_buffer *rb)
5019 struct ring_buffer *old_rb = NULL;
5020 unsigned long flags;
5024 * Should be impossible, we set this when removing
5025 * event->rb_entry and wait/clear when adding event->rb_entry.
5027 WARN_ON_ONCE(event->rcu_pending);
5030 spin_lock_irqsave(&old_rb->event_lock, flags);
5031 list_del_rcu(&event->rb_entry);
5032 spin_unlock_irqrestore(&old_rb->event_lock, flags);
5034 event->rcu_batches = get_state_synchronize_rcu();
5035 event->rcu_pending = 1;
5039 if (event->rcu_pending) {
5040 cond_synchronize_rcu(event->rcu_batches);
5041 event->rcu_pending = 0;
5044 spin_lock_irqsave(&rb->event_lock, flags);
5045 list_add_rcu(&event->rb_entry, &rb->event_list);
5046 spin_unlock_irqrestore(&rb->event_lock, flags);
5050 * Avoid racing with perf_mmap_close(AUX): stop the event
5051 * before swizzling the event::rb pointer; if it's getting
5052 * unmapped, its aux_mmap_count will be 0 and it won't
5053 * restart. See the comment in __perf_pmu_output_stop().
5055 * Data will inevitably be lost when set_output is done in
5056 * mid-air, but then again, whoever does it like this is
5057 * not in for the data anyway.
5060 perf_event_stop(event, 0);
5062 rcu_assign_pointer(event->rb, rb);
5065 ring_buffer_put(old_rb);
5067 * Since we detached before setting the new rb, so that we
5068 * could attach the new rb, we could have missed a wakeup.
5071 wake_up_all(&event->waitq);
5075 static void ring_buffer_wakeup(struct perf_event *event)
5077 struct ring_buffer *rb;
5080 rb = rcu_dereference(event->rb);
5082 list_for_each_entry_rcu(event, &rb->event_list, rb_entry)
5083 wake_up_all(&event->waitq);
5088 struct ring_buffer *ring_buffer_get(struct perf_event *event)
5090 struct ring_buffer *rb;
5093 rb = rcu_dereference(event->rb);
5095 if (!atomic_inc_not_zero(&rb->refcount))
5103 void ring_buffer_put(struct ring_buffer *rb)
5105 if (!atomic_dec_and_test(&rb->refcount))
5108 WARN_ON_ONCE(!list_empty(&rb->event_list));
5110 call_rcu(&rb->rcu_head, rb_free_rcu);
5113 static void perf_mmap_open(struct vm_area_struct *vma)
5115 struct perf_event *event = vma->vm_file->private_data;
5117 atomic_inc(&event->mmap_count);
5118 atomic_inc(&event->rb->mmap_count);
5121 atomic_inc(&event->rb->aux_mmap_count);
5123 if (event->pmu->event_mapped)
5124 event->pmu->event_mapped(event, vma->vm_mm);
5127 static void perf_pmu_output_stop(struct perf_event *event);
5130 * A buffer can be mmap()ed multiple times; either directly through the same
5131 * event, or through other events by use of perf_event_set_output().
5133 * In order to undo the VM accounting done by perf_mmap() we need to destroy
5134 * the buffer here, where we still have a VM context. This means we need
5135 * to detach all events redirecting to us.
5137 static void perf_mmap_close(struct vm_area_struct *vma)
5139 struct perf_event *event = vma->vm_file->private_data;
5141 struct ring_buffer *rb = ring_buffer_get(event);
5142 struct user_struct *mmap_user = rb->mmap_user;
5143 int mmap_locked = rb->mmap_locked;
5144 unsigned long size = perf_data_size(rb);
5146 if (event->pmu->event_unmapped)
5147 event->pmu->event_unmapped(event, vma->vm_mm);
5150 * rb->aux_mmap_count will always drop before rb->mmap_count and
5151 * event->mmap_count, so it is ok to use event->mmap_mutex to
5152 * serialize with perf_mmap here.
5154 if (rb_has_aux(rb) && vma->vm_pgoff == rb->aux_pgoff &&
5155 atomic_dec_and_mutex_lock(&rb->aux_mmap_count, &event->mmap_mutex)) {
5157 * Stop all AUX events that are writing to this buffer,
5158 * so that we can free its AUX pages and corresponding PMU
5159 * data. Note that after rb::aux_mmap_count dropped to zero,
5160 * they won't start any more (see perf_aux_output_begin()).
5162 perf_pmu_output_stop(event);
5164 /* now it's safe to free the pages */
5165 atomic_long_sub(rb->aux_nr_pages, &mmap_user->locked_vm);
5166 vma->vm_mm->pinned_vm -= rb->aux_mmap_locked;
5168 /* this has to be the last one */
5170 WARN_ON_ONCE(atomic_read(&rb->aux_refcount));
5172 mutex_unlock(&event->mmap_mutex);
5175 atomic_dec(&rb->mmap_count);
5177 if (!atomic_dec_and_mutex_lock(&event->mmap_count, &event->mmap_mutex))
5180 ring_buffer_attach(event, NULL);
5181 mutex_unlock(&event->mmap_mutex);
5183 /* If there's still other mmap()s of this buffer, we're done. */
5184 if (atomic_read(&rb->mmap_count))
5188 * No other mmap()s, detach from all other events that might redirect
5189 * into the now unreachable buffer. Somewhat complicated by the
5190 * fact that rb::event_lock otherwise nests inside mmap_mutex.
5194 list_for_each_entry_rcu(event, &rb->event_list, rb_entry) {
5195 if (!atomic_long_inc_not_zero(&event->refcount)) {
5197 * This event is en-route to free_event() which will
5198 * detach it and remove it from the list.
5204 mutex_lock(&event->mmap_mutex);
5206 * Check we didn't race with perf_event_set_output() which can
5207 * swizzle the rb from under us while we were waiting to
5208 * acquire mmap_mutex.
5210 * If we find a different rb; ignore this event, a next
5211 * iteration will no longer find it on the list. We have to
5212 * still restart the iteration to make sure we're not now
5213 * iterating the wrong list.
5215 if (event->rb == rb)
5216 ring_buffer_attach(event, NULL);
5218 mutex_unlock(&event->mmap_mutex);
5222 * Restart the iteration; either we're on the wrong list or
5223 * destroyed its integrity by doing a deletion.
5230 * It could be there's still a few 0-ref events on the list; they'll
5231 * get cleaned up by free_event() -- they'll also still have their
5232 * ref on the rb and will free it whenever they are done with it.
5234 * Aside from that, this buffer is 'fully' detached and unmapped,
5235 * undo the VM accounting.
5238 atomic_long_sub((size >> PAGE_SHIFT) + 1, &mmap_user->locked_vm);
5239 vma->vm_mm->pinned_vm -= mmap_locked;
5240 free_uid(mmap_user);
5243 ring_buffer_put(rb); /* could be last */
5246 static const struct vm_operations_struct perf_mmap_vmops = {
5247 .open = perf_mmap_open,
5248 .close = perf_mmap_close, /* non mergable */
5249 .fault = perf_mmap_fault,
5250 .page_mkwrite = perf_mmap_fault,
5253 static int perf_mmap(struct file *file, struct vm_area_struct *vma)
5255 struct perf_event *event = file->private_data;
5256 unsigned long user_locked, user_lock_limit;
5257 struct user_struct *user = current_user();
5258 unsigned long locked, lock_limit;
5259 struct ring_buffer *rb = NULL;
5260 unsigned long vma_size;
5261 unsigned long nr_pages;
5262 long user_extra = 0, extra = 0;
5263 int ret = 0, flags = 0;
5266 * Don't allow mmap() of inherited per-task counters. This would
5267 * create a performance issue due to all children writing to the
5270 if (event->cpu == -1 && event->attr.inherit)
5273 if (!(vma->vm_flags & VM_SHARED))
5276 vma_size = vma->vm_end - vma->vm_start;
5278 if (vma->vm_pgoff == 0) {
5279 nr_pages = (vma_size / PAGE_SIZE) - 1;
5282 * AUX area mapping: if rb->aux_nr_pages != 0, it's already
5283 * mapped, all subsequent mappings should have the same size
5284 * and offset. Must be above the normal perf buffer.
5286 u64 aux_offset, aux_size;
5291 nr_pages = vma_size / PAGE_SIZE;
5293 mutex_lock(&event->mmap_mutex);
5300 aux_offset = ACCESS_ONCE(rb->user_page->aux_offset);
5301 aux_size = ACCESS_ONCE(rb->user_page->aux_size);
5303 if (aux_offset < perf_data_size(rb) + PAGE_SIZE)
5306 if (aux_offset != vma->vm_pgoff << PAGE_SHIFT)
5309 /* already mapped with a different offset */
5310 if (rb_has_aux(rb) && rb->aux_pgoff != vma->vm_pgoff)
5313 if (aux_size != vma_size || aux_size != nr_pages * PAGE_SIZE)
5316 /* already mapped with a different size */
5317 if (rb_has_aux(rb) && rb->aux_nr_pages != nr_pages)
5320 if (!is_power_of_2(nr_pages))
5323 if (!atomic_inc_not_zero(&rb->mmap_count))
5326 if (rb_has_aux(rb)) {
5327 atomic_inc(&rb->aux_mmap_count);
5332 atomic_set(&rb->aux_mmap_count, 1);
5333 user_extra = nr_pages;
5339 * If we have rb pages ensure they're a power-of-two number, so we
5340 * can do bitmasks instead of modulo.
5342 if (nr_pages != 0 && !is_power_of_2(nr_pages))
5345 if (vma_size != PAGE_SIZE * (1 + nr_pages))
5348 WARN_ON_ONCE(event->ctx->parent_ctx);
5350 mutex_lock(&event->mmap_mutex);
5352 if (event->rb->nr_pages != nr_pages) {
5357 if (!atomic_inc_not_zero(&event->rb->mmap_count)) {
5359 * Raced against perf_mmap_close() through
5360 * perf_event_set_output(). Try again, hope for better
5363 mutex_unlock(&event->mmap_mutex);
5370 user_extra = nr_pages + 1;
5373 user_lock_limit = sysctl_perf_event_mlock >> (PAGE_SHIFT - 10);
5376 * Increase the limit linearly with more CPUs:
5378 user_lock_limit *= num_online_cpus();
5380 user_locked = atomic_long_read(&user->locked_vm) + user_extra;
5382 if (user_locked > user_lock_limit)
5383 extra = user_locked - user_lock_limit;
5385 lock_limit = rlimit(RLIMIT_MEMLOCK);
5386 lock_limit >>= PAGE_SHIFT;
5387 locked = vma->vm_mm->pinned_vm + extra;
5389 if ((locked > lock_limit) && perf_paranoid_tracepoint_raw() &&
5390 !capable(CAP_IPC_LOCK)) {
5395 WARN_ON(!rb && event->rb);
5397 if (vma->vm_flags & VM_WRITE)
5398 flags |= RING_BUFFER_WRITABLE;
5401 rb = rb_alloc(nr_pages,
5402 event->attr.watermark ? event->attr.wakeup_watermark : 0,
5410 atomic_set(&rb->mmap_count, 1);
5411 rb->mmap_user = get_current_user();
5412 rb->mmap_locked = extra;
5414 ring_buffer_attach(event, rb);
5416 perf_event_init_userpage(event);
5417 perf_event_update_userpage(event);
5419 ret = rb_alloc_aux(rb, event, vma->vm_pgoff, nr_pages,
5420 event->attr.aux_watermark, flags);
5422 rb->aux_mmap_locked = extra;
5427 atomic_long_add(user_extra, &user->locked_vm);
5428 vma->vm_mm->pinned_vm += extra;
5430 atomic_inc(&event->mmap_count);
5432 atomic_dec(&rb->mmap_count);
5435 mutex_unlock(&event->mmap_mutex);
5438 * Since pinned accounting is per vm we cannot allow fork() to copy our
5441 vma->vm_flags |= VM_DONTCOPY | VM_DONTEXPAND | VM_DONTDUMP;
5442 vma->vm_ops = &perf_mmap_vmops;
5444 if (event->pmu->event_mapped)
5445 event->pmu->event_mapped(event, vma->vm_mm);
5450 static int perf_fasync(int fd, struct file *filp, int on)
5452 struct inode *inode = file_inode(filp);
5453 struct perf_event *event = filp->private_data;
5457 retval = fasync_helper(fd, filp, on, &event->fasync);
5458 inode_unlock(inode);
5466 static const struct file_operations perf_fops = {
5467 .llseek = no_llseek,
5468 .release = perf_release,
5471 .unlocked_ioctl = perf_ioctl,
5472 .compat_ioctl = perf_compat_ioctl,
5474 .fasync = perf_fasync,
5480 * If there's data, ensure we set the poll() state and publish everything
5481 * to user-space before waking everybody up.
5484 static inline struct fasync_struct **perf_event_fasync(struct perf_event *event)
5486 /* only the parent has fasync state */
5488 event = event->parent;
5489 return &event->fasync;
5492 void perf_event_wakeup(struct perf_event *event)
5494 ring_buffer_wakeup(event);
5496 if (event->pending_kill) {
5497 kill_fasync(perf_event_fasync(event), SIGIO, event->pending_kill);
5498 event->pending_kill = 0;
5502 static void perf_pending_event(struct irq_work *entry)
5504 struct perf_event *event = container_of(entry,
5505 struct perf_event, pending);
5508 rctx = perf_swevent_get_recursion_context();
5510 * If we 'fail' here, that's OK, it means recursion is already disabled
5511 * and we won't recurse 'further'.
5514 if (event->pending_disable) {
5515 event->pending_disable = 0;
5516 perf_event_disable_local(event);
5519 if (event->pending_wakeup) {
5520 event->pending_wakeup = 0;
5521 perf_event_wakeup(event);
5525 perf_swevent_put_recursion_context(rctx);
5529 * We assume there is only KVM supporting the callbacks.
5530 * Later on, we might change it to a list if there is
5531 * another virtualization implementation supporting the callbacks.
5533 struct perf_guest_info_callbacks *perf_guest_cbs;
5535 int perf_register_guest_info_callbacks(struct perf_guest_info_callbacks *cbs)
5537 perf_guest_cbs = cbs;
5540 EXPORT_SYMBOL_GPL(perf_register_guest_info_callbacks);
5542 int perf_unregister_guest_info_callbacks(struct perf_guest_info_callbacks *cbs)
5544 perf_guest_cbs = NULL;
5547 EXPORT_SYMBOL_GPL(perf_unregister_guest_info_callbacks);
5550 perf_output_sample_regs(struct perf_output_handle *handle,
5551 struct pt_regs *regs, u64 mask)
5554 DECLARE_BITMAP(_mask, 64);
5556 bitmap_from_u64(_mask, mask);
5557 for_each_set_bit(bit, _mask, sizeof(mask) * BITS_PER_BYTE) {
5560 val = perf_reg_value(regs, bit);
5561 perf_output_put(handle, val);
5565 static void perf_sample_regs_user(struct perf_regs *regs_user,
5566 struct pt_regs *regs,
5567 struct pt_regs *regs_user_copy)
5569 if (user_mode(regs)) {
5570 regs_user->abi = perf_reg_abi(current);
5571 regs_user->regs = regs;
5572 } else if (current->mm) {
5573 perf_get_regs_user(regs_user, regs, regs_user_copy);
5575 regs_user->abi = PERF_SAMPLE_REGS_ABI_NONE;
5576 regs_user->regs = NULL;
5580 static void perf_sample_regs_intr(struct perf_regs *regs_intr,
5581 struct pt_regs *regs)
5583 regs_intr->regs = regs;
5584 regs_intr->abi = perf_reg_abi(current);
5589 * Get remaining task size from user stack pointer.
5591 * It'd be better to take stack vma map and limit this more
5592 * precisly, but there's no way to get it safely under interrupt,
5593 * so using TASK_SIZE as limit.
5595 static u64 perf_ustack_task_size(struct pt_regs *regs)
5597 unsigned long addr = perf_user_stack_pointer(regs);
5599 if (!addr || addr >= TASK_SIZE)
5602 return TASK_SIZE - addr;
5606 perf_sample_ustack_size(u16 stack_size, u16 header_size,
5607 struct pt_regs *regs)
5611 /* No regs, no stack pointer, no dump. */
5616 * Check if we fit in with the requested stack size into the:
5618 * If we don't, we limit the size to the TASK_SIZE.
5620 * - remaining sample size
5621 * If we don't, we customize the stack size to
5622 * fit in to the remaining sample size.
5625 task_size = min((u64) USHRT_MAX, perf_ustack_task_size(regs));
5626 stack_size = min(stack_size, (u16) task_size);
5628 /* Current header size plus static size and dynamic size. */
5629 header_size += 2 * sizeof(u64);
5631 /* Do we fit in with the current stack dump size? */
5632 if ((u16) (header_size + stack_size) < header_size) {
5634 * If we overflow the maximum size for the sample,
5635 * we customize the stack dump size to fit in.
5637 stack_size = USHRT_MAX - header_size - sizeof(u64);
5638 stack_size = round_up(stack_size, sizeof(u64));
5645 perf_output_sample_ustack(struct perf_output_handle *handle, u64 dump_size,
5646 struct pt_regs *regs)
5648 /* Case of a kernel thread, nothing to dump */
5651 perf_output_put(handle, size);
5660 * - the size requested by user or the best one we can fit
5661 * in to the sample max size
5663 * - user stack dump data
5665 * - the actual dumped size
5669 perf_output_put(handle, dump_size);
5672 sp = perf_user_stack_pointer(regs);
5673 rem = __output_copy_user(handle, (void *) sp, dump_size);
5674 dyn_size = dump_size - rem;
5676 perf_output_skip(handle, rem);
5679 perf_output_put(handle, dyn_size);
5683 static void __perf_event_header__init_id(struct perf_event_header *header,
5684 struct perf_sample_data *data,
5685 struct perf_event *event)
5687 u64 sample_type = event->attr.sample_type;
5689 data->type = sample_type;
5690 header->size += event->id_header_size;
5692 if (sample_type & PERF_SAMPLE_TID) {
5693 /* namespace issues */
5694 data->tid_entry.pid = perf_event_pid(event, current);
5695 data->tid_entry.tid = perf_event_tid(event, current);
5698 if (sample_type & PERF_SAMPLE_TIME)
5699 data->time = perf_event_clock(event);
5701 if (sample_type & (PERF_SAMPLE_ID | PERF_SAMPLE_IDENTIFIER))
5702 data->id = primary_event_id(event);
5704 if (sample_type & PERF_SAMPLE_STREAM_ID)
5705 data->stream_id = event->id;
5707 if (sample_type & PERF_SAMPLE_CPU) {
5708 data->cpu_entry.cpu = raw_smp_processor_id();
5709 data->cpu_entry.reserved = 0;
5713 void perf_event_header__init_id(struct perf_event_header *header,
5714 struct perf_sample_data *data,
5715 struct perf_event *event)
5717 if (event->attr.sample_id_all)
5718 __perf_event_header__init_id(header, data, event);
5721 static void __perf_event__output_id_sample(struct perf_output_handle *handle,
5722 struct perf_sample_data *data)
5724 u64 sample_type = data->type;
5726 if (sample_type & PERF_SAMPLE_TID)
5727 perf_output_put(handle, data->tid_entry);
5729 if (sample_type & PERF_SAMPLE_TIME)
5730 perf_output_put(handle, data->time);
5732 if (sample_type & PERF_SAMPLE_ID)
5733 perf_output_put(handle, data->id);
5735 if (sample_type & PERF_SAMPLE_STREAM_ID)
5736 perf_output_put(handle, data->stream_id);
5738 if (sample_type & PERF_SAMPLE_CPU)
5739 perf_output_put(handle, data->cpu_entry);
5741 if (sample_type & PERF_SAMPLE_IDENTIFIER)
5742 perf_output_put(handle, data->id);
5745 void perf_event__output_id_sample(struct perf_event *event,
5746 struct perf_output_handle *handle,
5747 struct perf_sample_data *sample)
5749 if (event->attr.sample_id_all)
5750 __perf_event__output_id_sample(handle, sample);
5753 static void perf_output_read_one(struct perf_output_handle *handle,
5754 struct perf_event *event,
5755 u64 enabled, u64 running)
5757 u64 read_format = event->attr.read_format;
5761 values[n++] = perf_event_count(event);
5762 if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED) {
5763 values[n++] = enabled +
5764 atomic64_read(&event->child_total_time_enabled);
5766 if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING) {
5767 values[n++] = running +
5768 atomic64_read(&event->child_total_time_running);
5770 if (read_format & PERF_FORMAT_ID)
5771 values[n++] = primary_event_id(event);
5773 __output_copy(handle, values, n * sizeof(u64));
5776 static void perf_output_read_group(struct perf_output_handle *handle,
5777 struct perf_event *event,
5778 u64 enabled, u64 running)
5780 struct perf_event *leader = event->group_leader, *sub;
5781 u64 read_format = event->attr.read_format;
5785 values[n++] = 1 + leader->nr_siblings;
5787 if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED)
5788 values[n++] = enabled;
5790 if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING)
5791 values[n++] = running;
5793 if (leader != event)
5794 leader->pmu->read(leader);
5796 values[n++] = perf_event_count(leader);
5797 if (read_format & PERF_FORMAT_ID)
5798 values[n++] = primary_event_id(leader);
5800 __output_copy(handle, values, n * sizeof(u64));
5802 list_for_each_entry(sub, &leader->sibling_list, group_entry) {
5805 if ((sub != event) &&
5806 (sub->state == PERF_EVENT_STATE_ACTIVE))
5807 sub->pmu->read(sub);
5809 values[n++] = perf_event_count(sub);
5810 if (read_format & PERF_FORMAT_ID)
5811 values[n++] = primary_event_id(sub);
5813 __output_copy(handle, values, n * sizeof(u64));
5817 #define PERF_FORMAT_TOTAL_TIMES (PERF_FORMAT_TOTAL_TIME_ENABLED|\
5818 PERF_FORMAT_TOTAL_TIME_RUNNING)
5821 * XXX PERF_SAMPLE_READ vs inherited events seems difficult.
5823 * The problem is that its both hard and excessively expensive to iterate the
5824 * child list, not to mention that its impossible to IPI the children running
5825 * on another CPU, from interrupt/NMI context.
5827 static void perf_output_read(struct perf_output_handle *handle,
5828 struct perf_event *event)
5830 u64 enabled = 0, running = 0, now;
5831 u64 read_format = event->attr.read_format;
5834 * compute total_time_enabled, total_time_running
5835 * based on snapshot values taken when the event
5836 * was last scheduled in.
5838 * we cannot simply called update_context_time()
5839 * because of locking issue as we are called in
5842 if (read_format & PERF_FORMAT_TOTAL_TIMES)
5843 calc_timer_values(event, &now, &enabled, &running);
5845 if (event->attr.read_format & PERF_FORMAT_GROUP)
5846 perf_output_read_group(handle, event, enabled, running);
5848 perf_output_read_one(handle, event, enabled, running);
5851 void perf_output_sample(struct perf_output_handle *handle,
5852 struct perf_event_header *header,
5853 struct perf_sample_data *data,
5854 struct perf_event *event)
5856 u64 sample_type = data->type;
5858 perf_output_put(handle, *header);
5860 if (sample_type & PERF_SAMPLE_IDENTIFIER)
5861 perf_output_put(handle, data->id);
5863 if (sample_type & PERF_SAMPLE_IP)
5864 perf_output_put(handle, data->ip);
5866 if (sample_type & PERF_SAMPLE_TID)
5867 perf_output_put(handle, data->tid_entry);
5869 if (sample_type & PERF_SAMPLE_TIME)
5870 perf_output_put(handle, data->time);
5872 if (sample_type & PERF_SAMPLE_ADDR)
5873 perf_output_put(handle, data->addr);
5875 if (sample_type & PERF_SAMPLE_ID)
5876 perf_output_put(handle, data->id);
5878 if (sample_type & PERF_SAMPLE_STREAM_ID)
5879 perf_output_put(handle, data->stream_id);
5881 if (sample_type & PERF_SAMPLE_CPU)
5882 perf_output_put(handle, data->cpu_entry);
5884 if (sample_type & PERF_SAMPLE_PERIOD)
5885 perf_output_put(handle, data->period);
5887 if (sample_type & PERF_SAMPLE_READ)
5888 perf_output_read(handle, event);
5890 if (sample_type & PERF_SAMPLE_CALLCHAIN) {
5891 if (data->callchain) {
5894 if (data->callchain)
5895 size += data->callchain->nr;
5897 size *= sizeof(u64);
5899 __output_copy(handle, data->callchain, size);
5902 perf_output_put(handle, nr);
5906 if (sample_type & PERF_SAMPLE_RAW) {
5907 struct perf_raw_record *raw = data->raw;
5910 struct perf_raw_frag *frag = &raw->frag;
5912 perf_output_put(handle, raw->size);
5915 __output_custom(handle, frag->copy,
5916 frag->data, frag->size);
5918 __output_copy(handle, frag->data,
5921 if (perf_raw_frag_last(frag))
5926 __output_skip(handle, NULL, frag->pad);
5932 .size = sizeof(u32),
5935 perf_output_put(handle, raw);
5939 if (sample_type & PERF_SAMPLE_BRANCH_STACK) {
5940 if (data->br_stack) {
5943 size = data->br_stack->nr
5944 * sizeof(struct perf_branch_entry);
5946 perf_output_put(handle, data->br_stack->nr);
5947 perf_output_copy(handle, data->br_stack->entries, size);
5950 * we always store at least the value of nr
5953 perf_output_put(handle, nr);
5957 if (sample_type & PERF_SAMPLE_REGS_USER) {
5958 u64 abi = data->regs_user.abi;
5961 * If there are no regs to dump, notice it through
5962 * first u64 being zero (PERF_SAMPLE_REGS_ABI_NONE).
5964 perf_output_put(handle, abi);
5967 u64 mask = event->attr.sample_regs_user;
5968 perf_output_sample_regs(handle,
5969 data->regs_user.regs,
5974 if (sample_type & PERF_SAMPLE_STACK_USER) {
5975 perf_output_sample_ustack(handle,
5976 data->stack_user_size,
5977 data->regs_user.regs);
5980 if (sample_type & PERF_SAMPLE_WEIGHT)
5981 perf_output_put(handle, data->weight);
5983 if (sample_type & PERF_SAMPLE_DATA_SRC)
5984 perf_output_put(handle, data->data_src.val);
5986 if (sample_type & PERF_SAMPLE_TRANSACTION)
5987 perf_output_put(handle, data->txn);
5989 if (sample_type & PERF_SAMPLE_REGS_INTR) {
5990 u64 abi = data->regs_intr.abi;
5992 * If there are no regs to dump, notice it through
5993 * first u64 being zero (PERF_SAMPLE_REGS_ABI_NONE).
5995 perf_output_put(handle, abi);
5998 u64 mask = event->attr.sample_regs_intr;
6000 perf_output_sample_regs(handle,
6001 data->regs_intr.regs,
6006 if (!event->attr.watermark) {
6007 int wakeup_events = event->attr.wakeup_events;
6009 if (wakeup_events) {
6010 struct ring_buffer *rb = handle->rb;
6011 int events = local_inc_return(&rb->events);
6013 if (events >= wakeup_events) {
6014 local_sub(wakeup_events, &rb->events);
6015 local_inc(&rb->wakeup);
6021 void perf_prepare_sample(struct perf_event_header *header,
6022 struct perf_sample_data *data,
6023 struct perf_event *event,
6024 struct pt_regs *regs)
6026 u64 sample_type = event->attr.sample_type;
6028 header->type = PERF_RECORD_SAMPLE;
6029 header->size = sizeof(*header) + event->header_size;
6032 header->misc |= perf_misc_flags(regs);
6034 __perf_event_header__init_id(header, data, event);
6036 if (sample_type & PERF_SAMPLE_IP)
6037 data->ip = perf_instruction_pointer(regs);
6039 if (sample_type & PERF_SAMPLE_CALLCHAIN) {
6042 data->callchain = perf_callchain(event, regs);
6044 if (data->callchain)
6045 size += data->callchain->nr;
6047 header->size += size * sizeof(u64);
6050 if (sample_type & PERF_SAMPLE_RAW) {
6051 struct perf_raw_record *raw = data->raw;
6055 struct perf_raw_frag *frag = &raw->frag;
6060 if (perf_raw_frag_last(frag))
6065 size = round_up(sum + sizeof(u32), sizeof(u64));
6066 raw->size = size - sizeof(u32);
6067 frag->pad = raw->size - sum;
6072 header->size += size;
6075 if (sample_type & PERF_SAMPLE_BRANCH_STACK) {
6076 int size = sizeof(u64); /* nr */
6077 if (data->br_stack) {
6078 size += data->br_stack->nr
6079 * sizeof(struct perf_branch_entry);
6081 header->size += size;
6084 if (sample_type & (PERF_SAMPLE_REGS_USER | PERF_SAMPLE_STACK_USER))
6085 perf_sample_regs_user(&data->regs_user, regs,
6086 &data->regs_user_copy);
6088 if (sample_type & PERF_SAMPLE_REGS_USER) {
6089 /* regs dump ABI info */
6090 int size = sizeof(u64);
6092 if (data->regs_user.regs) {
6093 u64 mask = event->attr.sample_regs_user;
6094 size += hweight64(mask) * sizeof(u64);
6097 header->size += size;
6100 if (sample_type & PERF_SAMPLE_STACK_USER) {
6102 * Either we need PERF_SAMPLE_STACK_USER bit to be allways
6103 * processed as the last one or have additional check added
6104 * in case new sample type is added, because we could eat
6105 * up the rest of the sample size.
6107 u16 stack_size = event->attr.sample_stack_user;
6108 u16 size = sizeof(u64);
6110 stack_size = perf_sample_ustack_size(stack_size, header->size,
6111 data->regs_user.regs);
6114 * If there is something to dump, add space for the dump
6115 * itself and for the field that tells the dynamic size,
6116 * which is how many have been actually dumped.
6119 size += sizeof(u64) + stack_size;
6121 data->stack_user_size = stack_size;
6122 header->size += size;
6125 if (sample_type & PERF_SAMPLE_REGS_INTR) {
6126 /* regs dump ABI info */
6127 int size = sizeof(u64);
6129 perf_sample_regs_intr(&data->regs_intr, regs);
6131 if (data->regs_intr.regs) {
6132 u64 mask = event->attr.sample_regs_intr;
6134 size += hweight64(mask) * sizeof(u64);
6137 header->size += size;
6141 static void __always_inline
6142 __perf_event_output(struct perf_event *event,
6143 struct perf_sample_data *data,
6144 struct pt_regs *regs,
6145 int (*output_begin)(struct perf_output_handle *,
6146 struct perf_event *,
6149 struct perf_output_handle handle;
6150 struct perf_event_header header;
6152 /* protect the callchain buffers */
6155 perf_prepare_sample(&header, data, event, regs);
6157 if (output_begin(&handle, event, header.size))
6160 perf_output_sample(&handle, &header, data, event);
6162 perf_output_end(&handle);
6169 perf_event_output_forward(struct perf_event *event,
6170 struct perf_sample_data *data,
6171 struct pt_regs *regs)
6173 __perf_event_output(event, data, regs, perf_output_begin_forward);
6177 perf_event_output_backward(struct perf_event *event,
6178 struct perf_sample_data *data,
6179 struct pt_regs *regs)
6181 __perf_event_output(event, data, regs, perf_output_begin_backward);
6185 perf_event_output(struct perf_event *event,
6186 struct perf_sample_data *data,
6187 struct pt_regs *regs)
6189 __perf_event_output(event, data, regs, perf_output_begin);
6196 struct perf_read_event {
6197 struct perf_event_header header;
6204 perf_event_read_event(struct perf_event *event,
6205 struct task_struct *task)
6207 struct perf_output_handle handle;
6208 struct perf_sample_data sample;
6209 struct perf_read_event read_event = {
6211 .type = PERF_RECORD_READ,
6213 .size = sizeof(read_event) + event->read_size,
6215 .pid = perf_event_pid(event, task),
6216 .tid = perf_event_tid(event, task),
6220 perf_event_header__init_id(&read_event.header, &sample, event);
6221 ret = perf_output_begin(&handle, event, read_event.header.size);
6225 perf_output_put(&handle, read_event);
6226 perf_output_read(&handle, event);
6227 perf_event__output_id_sample(event, &handle, &sample);
6229 perf_output_end(&handle);
6232 typedef void (perf_iterate_f)(struct perf_event *event, void *data);
6235 perf_iterate_ctx(struct perf_event_context *ctx,
6236 perf_iterate_f output,
6237 void *data, bool all)
6239 struct perf_event *event;
6241 list_for_each_entry_rcu(event, &ctx->event_list, event_entry) {
6243 if (event->state < PERF_EVENT_STATE_INACTIVE)
6245 if (!event_filter_match(event))
6249 output(event, data);
6253 static void perf_iterate_sb_cpu(perf_iterate_f output, void *data)
6255 struct pmu_event_list *pel = this_cpu_ptr(&pmu_sb_events);
6256 struct perf_event *event;
6258 list_for_each_entry_rcu(event, &pel->list, sb_list) {
6260 * Skip events that are not fully formed yet; ensure that
6261 * if we observe event->ctx, both event and ctx will be
6262 * complete enough. See perf_install_in_context().
6264 if (!smp_load_acquire(&event->ctx))
6267 if (event->state < PERF_EVENT_STATE_INACTIVE)
6269 if (!event_filter_match(event))
6271 output(event, data);
6276 * Iterate all events that need to receive side-band events.
6278 * For new callers; ensure that account_pmu_sb_event() includes
6279 * your event, otherwise it might not get delivered.
6282 perf_iterate_sb(perf_iterate_f output, void *data,
6283 struct perf_event_context *task_ctx)
6285 struct perf_event_context *ctx;
6292 * If we have task_ctx != NULL we only notify the task context itself.
6293 * The task_ctx is set only for EXIT events before releasing task
6297 perf_iterate_ctx(task_ctx, output, data, false);
6301 perf_iterate_sb_cpu(output, data);
6303 for_each_task_context_nr(ctxn) {
6304 ctx = rcu_dereference(current->perf_event_ctxp[ctxn]);
6306 perf_iterate_ctx(ctx, output, data, false);
6314 * Clear all file-based filters at exec, they'll have to be
6315 * re-instated when/if these objects are mmapped again.
6317 static void perf_event_addr_filters_exec(struct perf_event *event, void *data)
6319 struct perf_addr_filters_head *ifh = perf_event_addr_filters(event);
6320 struct perf_addr_filter *filter;
6321 unsigned int restart = 0, count = 0;
6322 unsigned long flags;
6324 if (!has_addr_filter(event))
6327 raw_spin_lock_irqsave(&ifh->lock, flags);
6328 list_for_each_entry(filter, &ifh->list, entry) {
6329 if (filter->inode) {
6330 event->addr_filters_offs[count] = 0;
6338 event->addr_filters_gen++;
6339 raw_spin_unlock_irqrestore(&ifh->lock, flags);
6342 perf_event_stop(event, 1);
6345 void perf_event_exec(void)
6347 struct perf_event_context *ctx;
6351 for_each_task_context_nr(ctxn) {
6352 ctx = current->perf_event_ctxp[ctxn];
6356 perf_event_enable_on_exec(ctxn);
6358 perf_iterate_ctx(ctx, perf_event_addr_filters_exec, NULL,
6364 struct remote_output {
6365 struct ring_buffer *rb;
6369 static void __perf_event_output_stop(struct perf_event *event, void *data)
6371 struct perf_event *parent = event->parent;
6372 struct remote_output *ro = data;
6373 struct ring_buffer *rb = ro->rb;
6374 struct stop_event_data sd = {
6378 if (!has_aux(event))
6385 * In case of inheritance, it will be the parent that links to the
6386 * ring-buffer, but it will be the child that's actually using it.
6388 * We are using event::rb to determine if the event should be stopped,
6389 * however this may race with ring_buffer_attach() (through set_output),
6390 * which will make us skip the event that actually needs to be stopped.
6391 * So ring_buffer_attach() has to stop an aux event before re-assigning
6394 if (rcu_dereference(parent->rb) == rb)
6395 ro->err = __perf_event_stop(&sd);
6398 static int __perf_pmu_output_stop(void *info)
6400 struct perf_event *event = info;
6401 struct pmu *pmu = event->pmu;
6402 struct perf_cpu_context *cpuctx = this_cpu_ptr(pmu->pmu_cpu_context);
6403 struct remote_output ro = {
6408 perf_iterate_ctx(&cpuctx->ctx, __perf_event_output_stop, &ro, false);
6409 if (cpuctx->task_ctx)
6410 perf_iterate_ctx(cpuctx->task_ctx, __perf_event_output_stop,
6417 static void perf_pmu_output_stop(struct perf_event *event)
6419 struct perf_event *iter;
6424 list_for_each_entry_rcu(iter, &event->rb->event_list, rb_entry) {
6426 * For per-CPU events, we need to make sure that neither they
6427 * nor their children are running; for cpu==-1 events it's
6428 * sufficient to stop the event itself if it's active, since
6429 * it can't have children.
6433 cpu = READ_ONCE(iter->oncpu);
6438 err = cpu_function_call(cpu, __perf_pmu_output_stop, event);
6439 if (err == -EAGAIN) {
6448 * task tracking -- fork/exit
6450 * enabled by: attr.comm | attr.mmap | attr.mmap2 | attr.mmap_data | attr.task
6453 struct perf_task_event {
6454 struct task_struct *task;
6455 struct perf_event_context *task_ctx;
6458 struct perf_event_header header;
6468 static int perf_event_task_match(struct perf_event *event)
6470 return event->attr.comm || event->attr.mmap ||
6471 event->attr.mmap2 || event->attr.mmap_data ||
6475 static void perf_event_task_output(struct perf_event *event,
6478 struct perf_task_event *task_event = data;
6479 struct perf_output_handle handle;
6480 struct perf_sample_data sample;
6481 struct task_struct *task = task_event->task;
6482 int ret, size = task_event->event_id.header.size;
6484 if (!perf_event_task_match(event))
6487 perf_event_header__init_id(&task_event->event_id.header, &sample, event);
6489 ret = perf_output_begin(&handle, event,
6490 task_event->event_id.header.size);
6494 task_event->event_id.pid = perf_event_pid(event, task);
6495 task_event->event_id.ppid = perf_event_pid(event, current);
6497 task_event->event_id.tid = perf_event_tid(event, task);
6498 task_event->event_id.ptid = perf_event_tid(event, current);
6500 task_event->event_id.time = perf_event_clock(event);
6502 perf_output_put(&handle, task_event->event_id);
6504 perf_event__output_id_sample(event, &handle, &sample);
6506 perf_output_end(&handle);
6508 task_event->event_id.header.size = size;
6511 static void perf_event_task(struct task_struct *task,
6512 struct perf_event_context *task_ctx,
6515 struct perf_task_event task_event;
6517 if (!atomic_read(&nr_comm_events) &&
6518 !atomic_read(&nr_mmap_events) &&
6519 !atomic_read(&nr_task_events))
6522 task_event = (struct perf_task_event){
6524 .task_ctx = task_ctx,
6527 .type = new ? PERF_RECORD_FORK : PERF_RECORD_EXIT,
6529 .size = sizeof(task_event.event_id),
6539 perf_iterate_sb(perf_event_task_output,
6544 void perf_event_fork(struct task_struct *task)
6546 perf_event_task(task, NULL, 1);
6547 perf_event_namespaces(task);
6554 struct perf_comm_event {
6555 struct task_struct *task;
6560 struct perf_event_header header;
6567 static int perf_event_comm_match(struct perf_event *event)
6569 return event->attr.comm;
6572 static void perf_event_comm_output(struct perf_event *event,
6575 struct perf_comm_event *comm_event = data;
6576 struct perf_output_handle handle;
6577 struct perf_sample_data sample;
6578 int size = comm_event->event_id.header.size;
6581 if (!perf_event_comm_match(event))
6584 perf_event_header__init_id(&comm_event->event_id.header, &sample, event);
6585 ret = perf_output_begin(&handle, event,
6586 comm_event->event_id.header.size);
6591 comm_event->event_id.pid = perf_event_pid(event, comm_event->task);
6592 comm_event->event_id.tid = perf_event_tid(event, comm_event->task);
6594 perf_output_put(&handle, comm_event->event_id);
6595 __output_copy(&handle, comm_event->comm,
6596 comm_event->comm_size);
6598 perf_event__output_id_sample(event, &handle, &sample);
6600 perf_output_end(&handle);
6602 comm_event->event_id.header.size = size;
6605 static void perf_event_comm_event(struct perf_comm_event *comm_event)
6607 char comm[TASK_COMM_LEN];
6610 memset(comm, 0, sizeof(comm));
6611 strlcpy(comm, comm_event->task->comm, sizeof(comm));
6612 size = ALIGN(strlen(comm)+1, sizeof(u64));
6614 comm_event->comm = comm;
6615 comm_event->comm_size = size;
6617 comm_event->event_id.header.size = sizeof(comm_event->event_id) + size;
6619 perf_iterate_sb(perf_event_comm_output,
6624 void perf_event_comm(struct task_struct *task, bool exec)
6626 struct perf_comm_event comm_event;
6628 if (!atomic_read(&nr_comm_events))
6631 comm_event = (struct perf_comm_event){
6637 .type = PERF_RECORD_COMM,
6638 .misc = exec ? PERF_RECORD_MISC_COMM_EXEC : 0,
6646 perf_event_comm_event(&comm_event);
6650 * namespaces tracking
6653 struct perf_namespaces_event {
6654 struct task_struct *task;
6657 struct perf_event_header header;
6662 struct perf_ns_link_info link_info[NR_NAMESPACES];
6666 static int perf_event_namespaces_match(struct perf_event *event)
6668 return event->attr.namespaces;
6671 static void perf_event_namespaces_output(struct perf_event *event,
6674 struct perf_namespaces_event *namespaces_event = data;
6675 struct perf_output_handle handle;
6676 struct perf_sample_data sample;
6679 if (!perf_event_namespaces_match(event))
6682 perf_event_header__init_id(&namespaces_event->event_id.header,
6684 ret = perf_output_begin(&handle, event,
6685 namespaces_event->event_id.header.size);
6689 namespaces_event->event_id.pid = perf_event_pid(event,
6690 namespaces_event->task);
6691 namespaces_event->event_id.tid = perf_event_tid(event,
6692 namespaces_event->task);
6694 perf_output_put(&handle, namespaces_event->event_id);
6696 perf_event__output_id_sample(event, &handle, &sample);
6698 perf_output_end(&handle);
6701 static void perf_fill_ns_link_info(struct perf_ns_link_info *ns_link_info,
6702 struct task_struct *task,
6703 const struct proc_ns_operations *ns_ops)
6705 struct path ns_path;
6706 struct inode *ns_inode;
6709 error = ns_get_path(&ns_path, task, ns_ops);
6711 ns_inode = ns_path.dentry->d_inode;
6712 ns_link_info->dev = new_encode_dev(ns_inode->i_sb->s_dev);
6713 ns_link_info->ino = ns_inode->i_ino;
6717 void perf_event_namespaces(struct task_struct *task)
6719 struct perf_namespaces_event namespaces_event;
6720 struct perf_ns_link_info *ns_link_info;
6722 if (!atomic_read(&nr_namespaces_events))
6725 namespaces_event = (struct perf_namespaces_event){
6729 .type = PERF_RECORD_NAMESPACES,
6731 .size = sizeof(namespaces_event.event_id),
6735 .nr_namespaces = NR_NAMESPACES,
6736 /* .link_info[NR_NAMESPACES] */
6740 ns_link_info = namespaces_event.event_id.link_info;
6742 perf_fill_ns_link_info(&ns_link_info[MNT_NS_INDEX],
6743 task, &mntns_operations);
6745 #ifdef CONFIG_USER_NS
6746 perf_fill_ns_link_info(&ns_link_info[USER_NS_INDEX],
6747 task, &userns_operations);
6749 #ifdef CONFIG_NET_NS
6750 perf_fill_ns_link_info(&ns_link_info[NET_NS_INDEX],
6751 task, &netns_operations);
6753 #ifdef CONFIG_UTS_NS
6754 perf_fill_ns_link_info(&ns_link_info[UTS_NS_INDEX],
6755 task, &utsns_operations);
6757 #ifdef CONFIG_IPC_NS
6758 perf_fill_ns_link_info(&ns_link_info[IPC_NS_INDEX],
6759 task, &ipcns_operations);
6761 #ifdef CONFIG_PID_NS
6762 perf_fill_ns_link_info(&ns_link_info[PID_NS_INDEX],
6763 task, &pidns_operations);
6765 #ifdef CONFIG_CGROUPS
6766 perf_fill_ns_link_info(&ns_link_info[CGROUP_NS_INDEX],
6767 task, &cgroupns_operations);
6770 perf_iterate_sb(perf_event_namespaces_output,
6779 struct perf_mmap_event {
6780 struct vm_area_struct *vma;
6782 const char *file_name;
6790 struct perf_event_header header;
6800 static int perf_event_mmap_match(struct perf_event *event,
6803 struct perf_mmap_event *mmap_event = data;
6804 struct vm_area_struct *vma = mmap_event->vma;
6805 int executable = vma->vm_flags & VM_EXEC;
6807 return (!executable && event->attr.mmap_data) ||
6808 (executable && (event->attr.mmap || event->attr.mmap2));
6811 static void perf_event_mmap_output(struct perf_event *event,
6814 struct perf_mmap_event *mmap_event = data;
6815 struct perf_output_handle handle;
6816 struct perf_sample_data sample;
6817 int size = mmap_event->event_id.header.size;
6820 if (!perf_event_mmap_match(event, data))
6823 if (event->attr.mmap2) {
6824 mmap_event->event_id.header.type = PERF_RECORD_MMAP2;
6825 mmap_event->event_id.header.size += sizeof(mmap_event->maj);
6826 mmap_event->event_id.header.size += sizeof(mmap_event->min);
6827 mmap_event->event_id.header.size += sizeof(mmap_event->ino);
6828 mmap_event->event_id.header.size += sizeof(mmap_event->ino_generation);
6829 mmap_event->event_id.header.size += sizeof(mmap_event->prot);
6830 mmap_event->event_id.header.size += sizeof(mmap_event->flags);
6833 perf_event_header__init_id(&mmap_event->event_id.header, &sample, event);
6834 ret = perf_output_begin(&handle, event,
6835 mmap_event->event_id.header.size);
6839 mmap_event->event_id.pid = perf_event_pid(event, current);
6840 mmap_event->event_id.tid = perf_event_tid(event, current);
6842 perf_output_put(&handle, mmap_event->event_id);
6844 if (event->attr.mmap2) {
6845 perf_output_put(&handle, mmap_event->maj);
6846 perf_output_put(&handle, mmap_event->min);
6847 perf_output_put(&handle, mmap_event->ino);
6848 perf_output_put(&handle, mmap_event->ino_generation);
6849 perf_output_put(&handle, mmap_event->prot);
6850 perf_output_put(&handle, mmap_event->flags);
6853 __output_copy(&handle, mmap_event->file_name,
6854 mmap_event->file_size);
6856 perf_event__output_id_sample(event, &handle, &sample);
6858 perf_output_end(&handle);
6860 mmap_event->event_id.header.size = size;
6863 static void perf_event_mmap_event(struct perf_mmap_event *mmap_event)
6865 struct vm_area_struct *vma = mmap_event->vma;
6866 struct file *file = vma->vm_file;
6867 int maj = 0, min = 0;
6868 u64 ino = 0, gen = 0;
6869 u32 prot = 0, flags = 0;
6875 if (vma->vm_flags & VM_READ)
6877 if (vma->vm_flags & VM_WRITE)
6879 if (vma->vm_flags & VM_EXEC)
6882 if (vma->vm_flags & VM_MAYSHARE)
6885 flags = MAP_PRIVATE;
6887 if (vma->vm_flags & VM_DENYWRITE)
6888 flags |= MAP_DENYWRITE;
6889 if (vma->vm_flags & VM_MAYEXEC)
6890 flags |= MAP_EXECUTABLE;
6891 if (vma->vm_flags & VM_LOCKED)
6892 flags |= MAP_LOCKED;
6893 if (vma->vm_flags & VM_HUGETLB)
6894 flags |= MAP_HUGETLB;
6897 struct inode *inode;
6900 buf = kmalloc(PATH_MAX, GFP_KERNEL);
6906 * d_path() works from the end of the rb backwards, so we
6907 * need to add enough zero bytes after the string to handle
6908 * the 64bit alignment we do later.
6910 name = file_path(file, buf, PATH_MAX - sizeof(u64));
6915 inode = file_inode(vma->vm_file);
6916 dev = inode->i_sb->s_dev;
6918 gen = inode->i_generation;
6924 if (vma->vm_ops && vma->vm_ops->name) {
6925 name = (char *) vma->vm_ops->name(vma);
6930 name = (char *)arch_vma_name(vma);
6934 if (vma->vm_start <= vma->vm_mm->start_brk &&
6935 vma->vm_end >= vma->vm_mm->brk) {
6939 if (vma->vm_start <= vma->vm_mm->start_stack &&
6940 vma->vm_end >= vma->vm_mm->start_stack) {
6950 strlcpy(tmp, name, sizeof(tmp));
6954 * Since our buffer works in 8 byte units we need to align our string
6955 * size to a multiple of 8. However, we must guarantee the tail end is
6956 * zero'd out to avoid leaking random bits to userspace.
6958 size = strlen(name)+1;
6959 while (!IS_ALIGNED(size, sizeof(u64)))
6960 name[size++] = '\0';
6962 mmap_event->file_name = name;
6963 mmap_event->file_size = size;
6964 mmap_event->maj = maj;
6965 mmap_event->min = min;
6966 mmap_event->ino = ino;
6967 mmap_event->ino_generation = gen;
6968 mmap_event->prot = prot;
6969 mmap_event->flags = flags;
6971 if (!(vma->vm_flags & VM_EXEC))
6972 mmap_event->event_id.header.misc |= PERF_RECORD_MISC_MMAP_DATA;
6974 mmap_event->event_id.header.size = sizeof(mmap_event->event_id) + size;
6976 perf_iterate_sb(perf_event_mmap_output,
6984 * Check whether inode and address range match filter criteria.
6986 static bool perf_addr_filter_match(struct perf_addr_filter *filter,
6987 struct file *file, unsigned long offset,
6990 if (filter->inode != file_inode(file))
6993 if (filter->offset > offset + size)
6996 if (filter->offset + filter->size < offset)
7002 static void __perf_addr_filters_adjust(struct perf_event *event, void *data)
7004 struct perf_addr_filters_head *ifh = perf_event_addr_filters(event);
7005 struct vm_area_struct *vma = data;
7006 unsigned long off = vma->vm_pgoff << PAGE_SHIFT, flags;
7007 struct file *file = vma->vm_file;
7008 struct perf_addr_filter *filter;
7009 unsigned int restart = 0, count = 0;
7011 if (!has_addr_filter(event))
7017 raw_spin_lock_irqsave(&ifh->lock, flags);
7018 list_for_each_entry(filter, &ifh->list, entry) {
7019 if (perf_addr_filter_match(filter, file, off,
7020 vma->vm_end - vma->vm_start)) {
7021 event->addr_filters_offs[count] = vma->vm_start;
7029 event->addr_filters_gen++;
7030 raw_spin_unlock_irqrestore(&ifh->lock, flags);
7033 perf_event_stop(event, 1);
7037 * Adjust all task's events' filters to the new vma
7039 static void perf_addr_filters_adjust(struct vm_area_struct *vma)
7041 struct perf_event_context *ctx;
7045 * Data tracing isn't supported yet and as such there is no need
7046 * to keep track of anything that isn't related to executable code:
7048 if (!(vma->vm_flags & VM_EXEC))
7052 for_each_task_context_nr(ctxn) {
7053 ctx = rcu_dereference(current->perf_event_ctxp[ctxn]);
7057 perf_iterate_ctx(ctx, __perf_addr_filters_adjust, vma, true);
7062 void perf_event_mmap(struct vm_area_struct *vma)
7064 struct perf_mmap_event mmap_event;
7066 if (!atomic_read(&nr_mmap_events))
7069 mmap_event = (struct perf_mmap_event){
7075 .type = PERF_RECORD_MMAP,
7076 .misc = PERF_RECORD_MISC_USER,
7081 .start = vma->vm_start,
7082 .len = vma->vm_end - vma->vm_start,
7083 .pgoff = (u64)vma->vm_pgoff << PAGE_SHIFT,
7085 /* .maj (attr_mmap2 only) */
7086 /* .min (attr_mmap2 only) */
7087 /* .ino (attr_mmap2 only) */
7088 /* .ino_generation (attr_mmap2 only) */
7089 /* .prot (attr_mmap2 only) */
7090 /* .flags (attr_mmap2 only) */
7093 perf_addr_filters_adjust(vma);
7094 perf_event_mmap_event(&mmap_event);
7097 void perf_event_aux_event(struct perf_event *event, unsigned long head,
7098 unsigned long size, u64 flags)
7100 struct perf_output_handle handle;
7101 struct perf_sample_data sample;
7102 struct perf_aux_event {
7103 struct perf_event_header header;
7109 .type = PERF_RECORD_AUX,
7111 .size = sizeof(rec),
7119 perf_event_header__init_id(&rec.header, &sample, event);
7120 ret = perf_output_begin(&handle, event, rec.header.size);
7125 perf_output_put(&handle, rec);
7126 perf_event__output_id_sample(event, &handle, &sample);
7128 perf_output_end(&handle);
7132 * Lost/dropped samples logging
7134 void perf_log_lost_samples(struct perf_event *event, u64 lost)
7136 struct perf_output_handle handle;
7137 struct perf_sample_data sample;
7141 struct perf_event_header header;
7143 } lost_samples_event = {
7145 .type = PERF_RECORD_LOST_SAMPLES,
7147 .size = sizeof(lost_samples_event),
7152 perf_event_header__init_id(&lost_samples_event.header, &sample, event);
7154 ret = perf_output_begin(&handle, event,
7155 lost_samples_event.header.size);
7159 perf_output_put(&handle, lost_samples_event);
7160 perf_event__output_id_sample(event, &handle, &sample);
7161 perf_output_end(&handle);
7165 * context_switch tracking
7168 struct perf_switch_event {
7169 struct task_struct *task;
7170 struct task_struct *next_prev;
7173 struct perf_event_header header;
7179 static int perf_event_switch_match(struct perf_event *event)
7181 return event->attr.context_switch;
7184 static void perf_event_switch_output(struct perf_event *event, void *data)
7186 struct perf_switch_event *se = data;
7187 struct perf_output_handle handle;
7188 struct perf_sample_data sample;
7191 if (!perf_event_switch_match(event))
7194 /* Only CPU-wide events are allowed to see next/prev pid/tid */
7195 if (event->ctx->task) {
7196 se->event_id.header.type = PERF_RECORD_SWITCH;
7197 se->event_id.header.size = sizeof(se->event_id.header);
7199 se->event_id.header.type = PERF_RECORD_SWITCH_CPU_WIDE;
7200 se->event_id.header.size = sizeof(se->event_id);
7201 se->event_id.next_prev_pid =
7202 perf_event_pid(event, se->next_prev);
7203 se->event_id.next_prev_tid =
7204 perf_event_tid(event, se->next_prev);
7207 perf_event_header__init_id(&se->event_id.header, &sample, event);
7209 ret = perf_output_begin(&handle, event, se->event_id.header.size);
7213 if (event->ctx->task)
7214 perf_output_put(&handle, se->event_id.header);
7216 perf_output_put(&handle, se->event_id);
7218 perf_event__output_id_sample(event, &handle, &sample);
7220 perf_output_end(&handle);
7223 static void perf_event_switch(struct task_struct *task,
7224 struct task_struct *next_prev, bool sched_in)
7226 struct perf_switch_event switch_event;
7228 /* N.B. caller checks nr_switch_events != 0 */
7230 switch_event = (struct perf_switch_event){
7232 .next_prev = next_prev,
7236 .misc = sched_in ? 0 : PERF_RECORD_MISC_SWITCH_OUT,
7239 /* .next_prev_pid */
7240 /* .next_prev_tid */
7244 perf_iterate_sb(perf_event_switch_output,
7250 * IRQ throttle logging
7253 static void perf_log_throttle(struct perf_event *event, int enable)
7255 struct perf_output_handle handle;
7256 struct perf_sample_data sample;
7260 struct perf_event_header header;
7264 } throttle_event = {
7266 .type = PERF_RECORD_THROTTLE,
7268 .size = sizeof(throttle_event),
7270 .time = perf_event_clock(event),
7271 .id = primary_event_id(event),
7272 .stream_id = event->id,
7276 throttle_event.header.type = PERF_RECORD_UNTHROTTLE;
7278 perf_event_header__init_id(&throttle_event.header, &sample, event);
7280 ret = perf_output_begin(&handle, event,
7281 throttle_event.header.size);
7285 perf_output_put(&handle, throttle_event);
7286 perf_event__output_id_sample(event, &handle, &sample);
7287 perf_output_end(&handle);
7290 static void perf_log_itrace_start(struct perf_event *event)
7292 struct perf_output_handle handle;
7293 struct perf_sample_data sample;
7294 struct perf_aux_event {
7295 struct perf_event_header header;
7302 event = event->parent;
7304 if (!(event->pmu->capabilities & PERF_PMU_CAP_ITRACE) ||
7305 event->hw.itrace_started)
7308 rec.header.type = PERF_RECORD_ITRACE_START;
7309 rec.header.misc = 0;
7310 rec.header.size = sizeof(rec);
7311 rec.pid = perf_event_pid(event, current);
7312 rec.tid = perf_event_tid(event, current);
7314 perf_event_header__init_id(&rec.header, &sample, event);
7315 ret = perf_output_begin(&handle, event, rec.header.size);
7320 perf_output_put(&handle, rec);
7321 perf_event__output_id_sample(event, &handle, &sample);
7323 perf_output_end(&handle);
7327 __perf_event_account_interrupt(struct perf_event *event, int throttle)
7329 struct hw_perf_event *hwc = &event->hw;
7333 seq = __this_cpu_read(perf_throttled_seq);
7334 if (seq != hwc->interrupts_seq) {
7335 hwc->interrupts_seq = seq;
7336 hwc->interrupts = 1;
7339 if (unlikely(throttle
7340 && hwc->interrupts >= max_samples_per_tick)) {
7341 __this_cpu_inc(perf_throttled_count);
7342 tick_dep_set_cpu(smp_processor_id(), TICK_DEP_BIT_PERF_EVENTS);
7343 hwc->interrupts = MAX_INTERRUPTS;
7344 perf_log_throttle(event, 0);
7349 if (event->attr.freq) {
7350 u64 now = perf_clock();
7351 s64 delta = now - hwc->freq_time_stamp;
7353 hwc->freq_time_stamp = now;
7355 if (delta > 0 && delta < 2*TICK_NSEC)
7356 perf_adjust_period(event, delta, hwc->last_period, true);
7362 int perf_event_account_interrupt(struct perf_event *event)
7364 return __perf_event_account_interrupt(event, 1);
7368 * Generic event overflow handling, sampling.
7371 static int __perf_event_overflow(struct perf_event *event,
7372 int throttle, struct perf_sample_data *data,
7373 struct pt_regs *regs)
7375 int events = atomic_read(&event->event_limit);
7379 * Non-sampling counters might still use the PMI to fold short
7380 * hardware counters, ignore those.
7382 if (unlikely(!is_sampling_event(event)))
7385 ret = __perf_event_account_interrupt(event, throttle);
7388 * XXX event_limit might not quite work as expected on inherited
7392 event->pending_kill = POLL_IN;
7393 if (events && atomic_dec_and_test(&event->event_limit)) {
7395 event->pending_kill = POLL_HUP;
7397 perf_event_disable_inatomic(event);
7400 READ_ONCE(event->overflow_handler)(event, data, regs);
7402 if (*perf_event_fasync(event) && event->pending_kill) {
7403 event->pending_wakeup = 1;
7404 irq_work_queue(&event->pending);
7410 int perf_event_overflow(struct perf_event *event,
7411 struct perf_sample_data *data,
7412 struct pt_regs *regs)
7414 return __perf_event_overflow(event, 1, data, regs);
7418 * Generic software event infrastructure
7421 struct swevent_htable {
7422 struct swevent_hlist *swevent_hlist;
7423 struct mutex hlist_mutex;
7426 /* Recursion avoidance in each contexts */
7427 int recursion[PERF_NR_CONTEXTS];
7430 static DEFINE_PER_CPU(struct swevent_htable, swevent_htable);
7433 * We directly increment event->count and keep a second value in
7434 * event->hw.period_left to count intervals. This period event
7435 * is kept in the range [-sample_period, 0] so that we can use the
7439 u64 perf_swevent_set_period(struct perf_event *event)
7441 struct hw_perf_event *hwc = &event->hw;
7442 u64 period = hwc->last_period;
7446 hwc->last_period = hwc->sample_period;
7449 old = val = local64_read(&hwc->period_left);
7453 nr = div64_u64(period + val, period);
7454 offset = nr * period;
7456 if (local64_cmpxchg(&hwc->period_left, old, val) != old)
7462 static void perf_swevent_overflow(struct perf_event *event, u64 overflow,
7463 struct perf_sample_data *data,
7464 struct pt_regs *regs)
7466 struct hw_perf_event *hwc = &event->hw;
7470 overflow = perf_swevent_set_period(event);
7472 if (hwc->interrupts == MAX_INTERRUPTS)
7475 for (; overflow; overflow--) {
7476 if (__perf_event_overflow(event, throttle,
7479 * We inhibit the overflow from happening when
7480 * hwc->interrupts == MAX_INTERRUPTS.
7488 static void perf_swevent_event(struct perf_event *event, u64 nr,
7489 struct perf_sample_data *data,
7490 struct pt_regs *regs)
7492 struct hw_perf_event *hwc = &event->hw;
7494 local64_add(nr, &event->count);
7499 if (!is_sampling_event(event))
7502 if ((event->attr.sample_type & PERF_SAMPLE_PERIOD) && !event->attr.freq) {
7504 return perf_swevent_overflow(event, 1, data, regs);
7506 data->period = event->hw.last_period;
7508 if (nr == 1 && hwc->sample_period == 1 && !event->attr.freq)
7509 return perf_swevent_overflow(event, 1, data, regs);
7511 if (local64_add_negative(nr, &hwc->period_left))
7514 perf_swevent_overflow(event, 0, data, regs);
7517 static int perf_exclude_event(struct perf_event *event,
7518 struct pt_regs *regs)
7520 if (event->hw.state & PERF_HES_STOPPED)
7524 if (event->attr.exclude_user && user_mode(regs))
7527 if (event->attr.exclude_kernel && !user_mode(regs))
7534 static int perf_swevent_match(struct perf_event *event,
7535 enum perf_type_id type,
7537 struct perf_sample_data *data,
7538 struct pt_regs *regs)
7540 if (event->attr.type != type)
7543 if (event->attr.config != event_id)
7546 if (perf_exclude_event(event, regs))
7552 static inline u64 swevent_hash(u64 type, u32 event_id)
7554 u64 val = event_id | (type << 32);
7556 return hash_64(val, SWEVENT_HLIST_BITS);
7559 static inline struct hlist_head *
7560 __find_swevent_head(struct swevent_hlist *hlist, u64 type, u32 event_id)
7562 u64 hash = swevent_hash(type, event_id);
7564 return &hlist->heads[hash];
7567 /* For the read side: events when they trigger */
7568 static inline struct hlist_head *
7569 find_swevent_head_rcu(struct swevent_htable *swhash, u64 type, u32 event_id)
7571 struct swevent_hlist *hlist;
7573 hlist = rcu_dereference(swhash->swevent_hlist);
7577 return __find_swevent_head(hlist, type, event_id);
7580 /* For the event head insertion and removal in the hlist */
7581 static inline struct hlist_head *
7582 find_swevent_head(struct swevent_htable *swhash, struct perf_event *event)
7584 struct swevent_hlist *hlist;
7585 u32 event_id = event->attr.config;
7586 u64 type = event->attr.type;
7589 * Event scheduling is always serialized against hlist allocation
7590 * and release. Which makes the protected version suitable here.
7591 * The context lock guarantees that.
7593 hlist = rcu_dereference_protected(swhash->swevent_hlist,
7594 lockdep_is_held(&event->ctx->lock));
7598 return __find_swevent_head(hlist, type, event_id);
7601 static void do_perf_sw_event(enum perf_type_id type, u32 event_id,
7603 struct perf_sample_data *data,
7604 struct pt_regs *regs)
7606 struct swevent_htable *swhash = this_cpu_ptr(&swevent_htable);
7607 struct perf_event *event;
7608 struct hlist_head *head;
7611 head = find_swevent_head_rcu(swhash, type, event_id);
7615 hlist_for_each_entry_rcu(event, head, hlist_entry) {
7616 if (perf_swevent_match(event, type, event_id, data, regs))
7617 perf_swevent_event(event, nr, data, regs);
7623 DEFINE_PER_CPU(struct pt_regs, __perf_regs[4]);
7625 int perf_swevent_get_recursion_context(void)
7627 struct swevent_htable *swhash = this_cpu_ptr(&swevent_htable);
7629 return get_recursion_context(swhash->recursion);
7631 EXPORT_SYMBOL_GPL(perf_swevent_get_recursion_context);
7633 void perf_swevent_put_recursion_context(int rctx)
7635 struct swevent_htable *swhash = this_cpu_ptr(&swevent_htable);
7637 put_recursion_context(swhash->recursion, rctx);
7640 void ___perf_sw_event(u32 event_id, u64 nr, struct pt_regs *regs, u64 addr)
7642 struct perf_sample_data data;
7644 if (WARN_ON_ONCE(!regs))
7647 perf_sample_data_init(&data, addr, 0);
7648 do_perf_sw_event(PERF_TYPE_SOFTWARE, event_id, nr, &data, regs);
7651 void __perf_sw_event(u32 event_id, u64 nr, struct pt_regs *regs, u64 addr)
7655 preempt_disable_notrace();
7656 rctx = perf_swevent_get_recursion_context();
7657 if (unlikely(rctx < 0))
7660 ___perf_sw_event(event_id, nr, regs, addr);
7662 perf_swevent_put_recursion_context(rctx);
7664 preempt_enable_notrace();
7667 static void perf_swevent_read(struct perf_event *event)
7671 static int perf_swevent_add(struct perf_event *event, int flags)
7673 struct swevent_htable *swhash = this_cpu_ptr(&swevent_htable);
7674 struct hw_perf_event *hwc = &event->hw;
7675 struct hlist_head *head;
7677 if (is_sampling_event(event)) {
7678 hwc->last_period = hwc->sample_period;
7679 perf_swevent_set_period(event);
7682 hwc->state = !(flags & PERF_EF_START);
7684 head = find_swevent_head(swhash, event);
7685 if (WARN_ON_ONCE(!head))
7688 hlist_add_head_rcu(&event->hlist_entry, head);
7689 perf_event_update_userpage(event);
7694 static void perf_swevent_del(struct perf_event *event, int flags)
7696 hlist_del_rcu(&event->hlist_entry);
7699 static void perf_swevent_start(struct perf_event *event, int flags)
7701 event->hw.state = 0;
7704 static void perf_swevent_stop(struct perf_event *event, int flags)
7706 event->hw.state = PERF_HES_STOPPED;
7709 /* Deref the hlist from the update side */
7710 static inline struct swevent_hlist *
7711 swevent_hlist_deref(struct swevent_htable *swhash)
7713 return rcu_dereference_protected(swhash->swevent_hlist,
7714 lockdep_is_held(&swhash->hlist_mutex));
7717 static void swevent_hlist_release(struct swevent_htable *swhash)
7719 struct swevent_hlist *hlist = swevent_hlist_deref(swhash);
7724 RCU_INIT_POINTER(swhash->swevent_hlist, NULL);
7725 kfree_rcu(hlist, rcu_head);
7728 static void swevent_hlist_put_cpu(int cpu)
7730 struct swevent_htable *swhash = &per_cpu(swevent_htable, cpu);
7732 mutex_lock(&swhash->hlist_mutex);
7734 if (!--swhash->hlist_refcount)
7735 swevent_hlist_release(swhash);
7737 mutex_unlock(&swhash->hlist_mutex);
7740 static void swevent_hlist_put(void)
7744 for_each_possible_cpu(cpu)
7745 swevent_hlist_put_cpu(cpu);
7748 static int swevent_hlist_get_cpu(int cpu)
7750 struct swevent_htable *swhash = &per_cpu(swevent_htable, cpu);
7753 mutex_lock(&swhash->hlist_mutex);
7754 if (!swevent_hlist_deref(swhash) &&
7755 cpumask_test_cpu(cpu, perf_online_mask)) {
7756 struct swevent_hlist *hlist;
7758 hlist = kzalloc(sizeof(*hlist), GFP_KERNEL);
7763 rcu_assign_pointer(swhash->swevent_hlist, hlist);
7765 swhash->hlist_refcount++;
7767 mutex_unlock(&swhash->hlist_mutex);
7772 static int swevent_hlist_get(void)
7774 int err, cpu, failed_cpu;
7776 mutex_lock(&pmus_lock);
7777 for_each_possible_cpu(cpu) {
7778 err = swevent_hlist_get_cpu(cpu);
7784 mutex_unlock(&pmus_lock);
7787 for_each_possible_cpu(cpu) {
7788 if (cpu == failed_cpu)
7790 swevent_hlist_put_cpu(cpu);
7792 mutex_unlock(&pmus_lock);
7796 struct static_key perf_swevent_enabled[PERF_COUNT_SW_MAX];
7798 static void sw_perf_event_destroy(struct perf_event *event)
7800 u64 event_id = event->attr.config;
7802 WARN_ON(event->parent);
7804 static_key_slow_dec(&perf_swevent_enabled[event_id]);
7805 swevent_hlist_put();
7808 static int perf_swevent_init(struct perf_event *event)
7810 u64 event_id = event->attr.config;
7812 if (event->attr.type != PERF_TYPE_SOFTWARE)
7816 * no branch sampling for software events
7818 if (has_branch_stack(event))
7822 case PERF_COUNT_SW_CPU_CLOCK:
7823 case PERF_COUNT_SW_TASK_CLOCK:
7830 if (event_id >= PERF_COUNT_SW_MAX)
7833 if (!event->parent) {
7836 err = swevent_hlist_get();
7840 static_key_slow_inc(&perf_swevent_enabled[event_id]);
7841 event->destroy = sw_perf_event_destroy;
7847 static struct pmu perf_swevent = {
7848 .task_ctx_nr = perf_sw_context,
7850 .capabilities = PERF_PMU_CAP_NO_NMI,
7852 .event_init = perf_swevent_init,
7853 .add = perf_swevent_add,
7854 .del = perf_swevent_del,
7855 .start = perf_swevent_start,
7856 .stop = perf_swevent_stop,
7857 .read = perf_swevent_read,
7860 #ifdef CONFIG_EVENT_TRACING
7862 static int perf_tp_filter_match(struct perf_event *event,
7863 struct perf_sample_data *data)
7865 void *record = data->raw->frag.data;
7867 /* only top level events have filters set */
7869 event = event->parent;
7871 if (likely(!event->filter) || filter_match_preds(event->filter, record))
7876 static int perf_tp_event_match(struct perf_event *event,
7877 struct perf_sample_data *data,
7878 struct pt_regs *regs)
7880 if (event->hw.state & PERF_HES_STOPPED)
7883 * All tracepoints are from kernel-space.
7885 if (event->attr.exclude_kernel)
7888 if (!perf_tp_filter_match(event, data))
7894 void perf_trace_run_bpf_submit(void *raw_data, int size, int rctx,
7895 struct trace_event_call *call, u64 count,
7896 struct pt_regs *regs, struct hlist_head *head,
7897 struct task_struct *task)
7899 struct bpf_prog *prog = call->prog;
7902 *(struct pt_regs **)raw_data = regs;
7903 if (!trace_call_bpf(prog, raw_data) || hlist_empty(head)) {
7904 perf_swevent_put_recursion_context(rctx);
7908 perf_tp_event(call->event.type, count, raw_data, size, regs, head,
7911 EXPORT_SYMBOL_GPL(perf_trace_run_bpf_submit);
7913 void perf_tp_event(u16 event_type, u64 count, void *record, int entry_size,
7914 struct pt_regs *regs, struct hlist_head *head, int rctx,
7915 struct task_struct *task)
7917 struct perf_sample_data data;
7918 struct perf_event *event;
7920 struct perf_raw_record raw = {
7927 perf_sample_data_init(&data, 0, 0);
7930 perf_trace_buf_update(record, event_type);
7932 hlist_for_each_entry_rcu(event, head, hlist_entry) {
7933 if (perf_tp_event_match(event, &data, regs))
7934 perf_swevent_event(event, count, &data, regs);
7938 * If we got specified a target task, also iterate its context and
7939 * deliver this event there too.
7941 if (task && task != current) {
7942 struct perf_event_context *ctx;
7943 struct trace_entry *entry = record;
7946 ctx = rcu_dereference(task->perf_event_ctxp[perf_sw_context]);
7950 list_for_each_entry_rcu(event, &ctx->event_list, event_entry) {
7951 if (event->attr.type != PERF_TYPE_TRACEPOINT)
7953 if (event->attr.config != entry->type)
7955 if (perf_tp_event_match(event, &data, regs))
7956 perf_swevent_event(event, count, &data, regs);
7962 perf_swevent_put_recursion_context(rctx);
7964 EXPORT_SYMBOL_GPL(perf_tp_event);
7966 static void tp_perf_event_destroy(struct perf_event *event)
7968 perf_trace_destroy(event);
7971 static int perf_tp_event_init(struct perf_event *event)
7975 if (event->attr.type != PERF_TYPE_TRACEPOINT)
7979 * no branch sampling for tracepoint events
7981 if (has_branch_stack(event))
7984 err = perf_trace_init(event);
7988 event->destroy = tp_perf_event_destroy;
7993 static struct pmu perf_tracepoint = {
7994 .task_ctx_nr = perf_sw_context,
7996 .event_init = perf_tp_event_init,
7997 .add = perf_trace_add,
7998 .del = perf_trace_del,
7999 .start = perf_swevent_start,
8000 .stop = perf_swevent_stop,
8001 .read = perf_swevent_read,
8004 static inline void perf_tp_register(void)
8006 perf_pmu_register(&perf_tracepoint, "tracepoint", PERF_TYPE_TRACEPOINT);
8009 static void perf_event_free_filter(struct perf_event *event)
8011 ftrace_profile_free_filter(event);
8014 #ifdef CONFIG_BPF_SYSCALL
8015 static void bpf_overflow_handler(struct perf_event *event,
8016 struct perf_sample_data *data,
8017 struct pt_regs *regs)
8019 struct bpf_perf_event_data_kern ctx = {
8026 if (unlikely(__this_cpu_inc_return(bpf_prog_active) != 1))
8029 ret = BPF_PROG_RUN(event->prog, &ctx);
8032 __this_cpu_dec(bpf_prog_active);
8037 event->orig_overflow_handler(event, data, regs);
8040 static int perf_event_set_bpf_handler(struct perf_event *event, u32 prog_fd)
8042 struct bpf_prog *prog;
8044 if (event->overflow_handler_context)
8045 /* hw breakpoint or kernel counter */
8051 prog = bpf_prog_get_type(prog_fd, BPF_PROG_TYPE_PERF_EVENT);
8053 return PTR_ERR(prog);
8056 event->orig_overflow_handler = READ_ONCE(event->overflow_handler);
8057 WRITE_ONCE(event->overflow_handler, bpf_overflow_handler);
8061 static void perf_event_free_bpf_handler(struct perf_event *event)
8063 struct bpf_prog *prog = event->prog;
8068 WRITE_ONCE(event->overflow_handler, event->orig_overflow_handler);
8073 static int perf_event_set_bpf_handler(struct perf_event *event, u32 prog_fd)
8077 static void perf_event_free_bpf_handler(struct perf_event *event)
8082 static int perf_event_set_bpf_prog(struct perf_event *event, u32 prog_fd)
8084 bool is_kprobe, is_tracepoint;
8085 struct bpf_prog *prog;
8087 if (event->attr.type != PERF_TYPE_TRACEPOINT)
8088 return perf_event_set_bpf_handler(event, prog_fd);
8090 if (event->tp_event->prog)
8093 is_kprobe = event->tp_event->flags & TRACE_EVENT_FL_UKPROBE;
8094 is_tracepoint = event->tp_event->flags & TRACE_EVENT_FL_TRACEPOINT;
8095 if (!is_kprobe && !is_tracepoint)
8096 /* bpf programs can only be attached to u/kprobe or tracepoint */
8099 prog = bpf_prog_get(prog_fd);
8101 return PTR_ERR(prog);
8103 if ((is_kprobe && prog->type != BPF_PROG_TYPE_KPROBE) ||
8104 (is_tracepoint && prog->type != BPF_PROG_TYPE_TRACEPOINT)) {
8105 /* valid fd, but invalid bpf program type */
8110 if (is_tracepoint) {
8111 int off = trace_event_get_offsets(event->tp_event);
8113 if (prog->aux->max_ctx_offset > off) {
8118 event->tp_event->prog = prog;
8123 static void perf_event_free_bpf_prog(struct perf_event *event)
8125 struct bpf_prog *prog;
8127 perf_event_free_bpf_handler(event);
8129 if (!event->tp_event)
8132 prog = event->tp_event->prog;
8134 event->tp_event->prog = NULL;
8141 static inline void perf_tp_register(void)
8145 static void perf_event_free_filter(struct perf_event *event)
8149 static int perf_event_set_bpf_prog(struct perf_event *event, u32 prog_fd)
8154 static void perf_event_free_bpf_prog(struct perf_event *event)
8157 #endif /* CONFIG_EVENT_TRACING */
8159 #ifdef CONFIG_HAVE_HW_BREAKPOINT
8160 void perf_bp_event(struct perf_event *bp, void *data)
8162 struct perf_sample_data sample;
8163 struct pt_regs *regs = data;
8165 perf_sample_data_init(&sample, bp->attr.bp_addr, 0);
8167 if (!bp->hw.state && !perf_exclude_event(bp, regs))
8168 perf_swevent_event(bp, 1, &sample, regs);
8173 * Allocate a new address filter
8175 static struct perf_addr_filter *
8176 perf_addr_filter_new(struct perf_event *event, struct list_head *filters)
8178 int node = cpu_to_node(event->cpu == -1 ? 0 : event->cpu);
8179 struct perf_addr_filter *filter;
8181 filter = kzalloc_node(sizeof(*filter), GFP_KERNEL, node);
8185 INIT_LIST_HEAD(&filter->entry);
8186 list_add_tail(&filter->entry, filters);
8191 static void free_filters_list(struct list_head *filters)
8193 struct perf_addr_filter *filter, *iter;
8195 list_for_each_entry_safe(filter, iter, filters, entry) {
8197 iput(filter->inode);
8198 list_del(&filter->entry);
8204 * Free existing address filters and optionally install new ones
8206 static void perf_addr_filters_splice(struct perf_event *event,
8207 struct list_head *head)
8209 unsigned long flags;
8212 if (!has_addr_filter(event))
8215 /* don't bother with children, they don't have their own filters */
8219 raw_spin_lock_irqsave(&event->addr_filters.lock, flags);
8221 list_splice_init(&event->addr_filters.list, &list);
8223 list_splice(head, &event->addr_filters.list);
8225 raw_spin_unlock_irqrestore(&event->addr_filters.lock, flags);
8227 free_filters_list(&list);
8231 * Scan through mm's vmas and see if one of them matches the
8232 * @filter; if so, adjust filter's address range.
8233 * Called with mm::mmap_sem down for reading.
8235 static unsigned long perf_addr_filter_apply(struct perf_addr_filter *filter,
8236 struct mm_struct *mm)
8238 struct vm_area_struct *vma;
8240 for (vma = mm->mmap; vma; vma = vma->vm_next) {
8241 struct file *file = vma->vm_file;
8242 unsigned long off = vma->vm_pgoff << PAGE_SHIFT;
8243 unsigned long vma_size = vma->vm_end - vma->vm_start;
8248 if (!perf_addr_filter_match(filter, file, off, vma_size))
8251 return vma->vm_start;
8258 * Update event's address range filters based on the
8259 * task's existing mappings, if any.
8261 static void perf_event_addr_filters_apply(struct perf_event *event)
8263 struct perf_addr_filters_head *ifh = perf_event_addr_filters(event);
8264 struct task_struct *task = READ_ONCE(event->ctx->task);
8265 struct perf_addr_filter *filter;
8266 struct mm_struct *mm = NULL;
8267 unsigned int count = 0;
8268 unsigned long flags;
8271 * We may observe TASK_TOMBSTONE, which means that the event tear-down
8272 * will stop on the parent's child_mutex that our caller is also holding
8274 if (task == TASK_TOMBSTONE)
8277 if (!ifh->nr_file_filters)
8280 mm = get_task_mm(event->ctx->task);
8284 down_read(&mm->mmap_sem);
8286 raw_spin_lock_irqsave(&ifh->lock, flags);
8287 list_for_each_entry(filter, &ifh->list, entry) {
8288 event->addr_filters_offs[count] = 0;
8291 * Adjust base offset if the filter is associated to a binary
8292 * that needs to be mapped:
8295 event->addr_filters_offs[count] =
8296 perf_addr_filter_apply(filter, mm);
8301 event->addr_filters_gen++;
8302 raw_spin_unlock_irqrestore(&ifh->lock, flags);
8304 up_read(&mm->mmap_sem);
8309 perf_event_stop(event, 1);
8313 * Address range filtering: limiting the data to certain
8314 * instruction address ranges. Filters are ioctl()ed to us from
8315 * userspace as ascii strings.
8317 * Filter string format:
8320 * where ACTION is one of the
8321 * * "filter": limit the trace to this region
8322 * * "start": start tracing from this address
8323 * * "stop": stop tracing at this address/region;
8325 * * for kernel addresses: <start address>[/<size>]
8326 * * for object files: <start address>[/<size>]@</path/to/object/file>
8328 * if <size> is not specified, the range is treated as a single address.
8342 IF_STATE_ACTION = 0,
8347 static const match_table_t if_tokens = {
8348 { IF_ACT_FILTER, "filter" },
8349 { IF_ACT_START, "start" },
8350 { IF_ACT_STOP, "stop" },
8351 { IF_SRC_FILE, "%u/%u@%s" },
8352 { IF_SRC_KERNEL, "%u/%u" },
8353 { IF_SRC_FILEADDR, "%u@%s" },
8354 { IF_SRC_KERNELADDR, "%u" },
8355 { IF_ACT_NONE, NULL },
8359 * Address filter string parser
8362 perf_event_parse_addr_filter(struct perf_event *event, char *fstr,
8363 struct list_head *filters)
8365 struct perf_addr_filter *filter = NULL;
8366 char *start, *orig, *filename = NULL;
8368 substring_t args[MAX_OPT_ARGS];
8369 int state = IF_STATE_ACTION, token;
8370 unsigned int kernel = 0;
8373 orig = fstr = kstrdup(fstr, GFP_KERNEL);
8377 while ((start = strsep(&fstr, " ,\n")) != NULL) {
8383 /* filter definition begins */
8384 if (state == IF_STATE_ACTION) {
8385 filter = perf_addr_filter_new(event, filters);
8390 token = match_token(start, if_tokens, args);
8397 if (state != IF_STATE_ACTION)
8400 state = IF_STATE_SOURCE;
8403 case IF_SRC_KERNELADDR:
8407 case IF_SRC_FILEADDR:
8409 if (state != IF_STATE_SOURCE)
8412 if (token == IF_SRC_FILE || token == IF_SRC_KERNEL)
8416 ret = kstrtoul(args[0].from, 0, &filter->offset);
8420 if (filter->range) {
8422 ret = kstrtoul(args[1].from, 0, &filter->size);
8427 if (token == IF_SRC_FILE || token == IF_SRC_FILEADDR) {
8428 int fpos = filter->range ? 2 : 1;
8430 filename = match_strdup(&args[fpos]);
8437 state = IF_STATE_END;
8445 * Filter definition is fully parsed, validate and install it.
8446 * Make sure that it doesn't contradict itself or the event's
8449 if (state == IF_STATE_END) {
8451 if (kernel && event->attr.exclude_kernel)
8459 * For now, we only support file-based filters
8460 * in per-task events; doing so for CPU-wide
8461 * events requires additional context switching
8462 * trickery, since same object code will be
8463 * mapped at different virtual addresses in
8464 * different processes.
8467 if (!event->ctx->task)
8468 goto fail_free_name;
8470 /* look up the path and grab its inode */
8471 ret = kern_path(filename, LOOKUP_FOLLOW, &path);
8473 goto fail_free_name;
8475 filter->inode = igrab(d_inode(path.dentry));
8481 if (!filter->inode ||
8482 !S_ISREG(filter->inode->i_mode))
8483 /* free_filters_list() will iput() */
8486 event->addr_filters.nr_file_filters++;
8489 /* ready to consume more filters */
8490 state = IF_STATE_ACTION;
8495 if (state != IF_STATE_ACTION)
8505 free_filters_list(filters);
8512 perf_event_set_addr_filter(struct perf_event *event, char *filter_str)
8518 * Since this is called in perf_ioctl() path, we're already holding
8521 lockdep_assert_held(&event->ctx->mutex);
8523 if (WARN_ON_ONCE(event->parent))
8526 ret = perf_event_parse_addr_filter(event, filter_str, &filters);
8528 goto fail_clear_files;
8530 ret = event->pmu->addr_filters_validate(&filters);
8532 goto fail_free_filters;
8534 /* remove existing filters, if any */
8535 perf_addr_filters_splice(event, &filters);
8537 /* install new filters */
8538 perf_event_for_each_child(event, perf_event_addr_filters_apply);
8543 free_filters_list(&filters);
8546 event->addr_filters.nr_file_filters = 0;
8551 static int perf_event_set_filter(struct perf_event *event, void __user *arg)
8556 if ((event->attr.type != PERF_TYPE_TRACEPOINT ||
8557 !IS_ENABLED(CONFIG_EVENT_TRACING)) &&
8558 !has_addr_filter(event))
8561 filter_str = strndup_user(arg, PAGE_SIZE);
8562 if (IS_ERR(filter_str))
8563 return PTR_ERR(filter_str);
8565 if (IS_ENABLED(CONFIG_EVENT_TRACING) &&
8566 event->attr.type == PERF_TYPE_TRACEPOINT)
8567 ret = ftrace_profile_set_filter(event, event->attr.config,
8569 else if (has_addr_filter(event))
8570 ret = perf_event_set_addr_filter(event, filter_str);
8577 * hrtimer based swevent callback
8580 static enum hrtimer_restart perf_swevent_hrtimer(struct hrtimer *hrtimer)
8582 enum hrtimer_restart ret = HRTIMER_RESTART;
8583 struct perf_sample_data data;
8584 struct pt_regs *regs;
8585 struct perf_event *event;
8588 event = container_of(hrtimer, struct perf_event, hw.hrtimer);
8590 if (event->state != PERF_EVENT_STATE_ACTIVE)
8591 return HRTIMER_NORESTART;
8593 event->pmu->read(event);
8595 perf_sample_data_init(&data, 0, event->hw.last_period);
8596 regs = get_irq_regs();
8598 if (regs && !perf_exclude_event(event, regs)) {
8599 if (!(event->attr.exclude_idle && is_idle_task(current)))
8600 if (__perf_event_overflow(event, 1, &data, regs))
8601 ret = HRTIMER_NORESTART;
8604 period = max_t(u64, 10000, event->hw.sample_period);
8605 hrtimer_forward_now(hrtimer, ns_to_ktime(period));
8610 static void perf_swevent_start_hrtimer(struct perf_event *event)
8612 struct hw_perf_event *hwc = &event->hw;
8615 if (!is_sampling_event(event))
8618 period = local64_read(&hwc->period_left);
8623 local64_set(&hwc->period_left, 0);
8625 period = max_t(u64, 10000, hwc->sample_period);
8627 hrtimer_start(&hwc->hrtimer, ns_to_ktime(period),
8628 HRTIMER_MODE_REL_PINNED);
8631 static void perf_swevent_cancel_hrtimer(struct perf_event *event)
8633 struct hw_perf_event *hwc = &event->hw;
8635 if (is_sampling_event(event)) {
8636 ktime_t remaining = hrtimer_get_remaining(&hwc->hrtimer);
8637 local64_set(&hwc->period_left, ktime_to_ns(remaining));
8639 hrtimer_cancel(&hwc->hrtimer);
8643 static void perf_swevent_init_hrtimer(struct perf_event *event)
8645 struct hw_perf_event *hwc = &event->hw;
8647 if (!is_sampling_event(event))
8650 hrtimer_init(&hwc->hrtimer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
8651 hwc->hrtimer.function = perf_swevent_hrtimer;
8654 * Since hrtimers have a fixed rate, we can do a static freq->period
8655 * mapping and avoid the whole period adjust feedback stuff.
8657 if (event->attr.freq) {
8658 long freq = event->attr.sample_freq;
8660 event->attr.sample_period = NSEC_PER_SEC / freq;
8661 hwc->sample_period = event->attr.sample_period;
8662 local64_set(&hwc->period_left, hwc->sample_period);
8663 hwc->last_period = hwc->sample_period;
8664 event->attr.freq = 0;
8669 * Software event: cpu wall time clock
8672 static void cpu_clock_event_update(struct perf_event *event)
8677 now = local_clock();
8678 prev = local64_xchg(&event->hw.prev_count, now);
8679 local64_add(now - prev, &event->count);
8682 static void cpu_clock_event_start(struct perf_event *event, int flags)
8684 local64_set(&event->hw.prev_count, local_clock());
8685 perf_swevent_start_hrtimer(event);
8688 static void cpu_clock_event_stop(struct perf_event *event, int flags)
8690 perf_swevent_cancel_hrtimer(event);
8691 cpu_clock_event_update(event);
8694 static int cpu_clock_event_add(struct perf_event *event, int flags)
8696 if (flags & PERF_EF_START)
8697 cpu_clock_event_start(event, flags);
8698 perf_event_update_userpage(event);
8703 static void cpu_clock_event_del(struct perf_event *event, int flags)
8705 cpu_clock_event_stop(event, flags);
8708 static void cpu_clock_event_read(struct perf_event *event)
8710 cpu_clock_event_update(event);
8713 static int cpu_clock_event_init(struct perf_event *event)
8715 if (event->attr.type != PERF_TYPE_SOFTWARE)
8718 if (event->attr.config != PERF_COUNT_SW_CPU_CLOCK)
8722 * no branch sampling for software events
8724 if (has_branch_stack(event))
8727 perf_swevent_init_hrtimer(event);
8732 static struct pmu perf_cpu_clock = {
8733 .task_ctx_nr = perf_sw_context,
8735 .capabilities = PERF_PMU_CAP_NO_NMI,
8737 .event_init = cpu_clock_event_init,
8738 .add = cpu_clock_event_add,
8739 .del = cpu_clock_event_del,
8740 .start = cpu_clock_event_start,
8741 .stop = cpu_clock_event_stop,
8742 .read = cpu_clock_event_read,
8746 * Software event: task time clock
8749 static void task_clock_event_update(struct perf_event *event, u64 now)
8754 prev = local64_xchg(&event->hw.prev_count, now);
8756 local64_add(delta, &event->count);
8759 static void task_clock_event_start(struct perf_event *event, int flags)
8761 local64_set(&event->hw.prev_count, event->ctx->time);
8762 perf_swevent_start_hrtimer(event);
8765 static void task_clock_event_stop(struct perf_event *event, int flags)
8767 perf_swevent_cancel_hrtimer(event);
8768 task_clock_event_update(event, event->ctx->time);
8771 static int task_clock_event_add(struct perf_event *event, int flags)
8773 if (flags & PERF_EF_START)
8774 task_clock_event_start(event, flags);
8775 perf_event_update_userpage(event);
8780 static void task_clock_event_del(struct perf_event *event, int flags)
8782 task_clock_event_stop(event, PERF_EF_UPDATE);
8785 static void task_clock_event_read(struct perf_event *event)
8787 u64 now = perf_clock();
8788 u64 delta = now - event->ctx->timestamp;
8789 u64 time = event->ctx->time + delta;
8791 task_clock_event_update(event, time);
8794 static int task_clock_event_init(struct perf_event *event)
8796 if (event->attr.type != PERF_TYPE_SOFTWARE)
8799 if (event->attr.config != PERF_COUNT_SW_TASK_CLOCK)
8803 * no branch sampling for software events
8805 if (has_branch_stack(event))
8808 perf_swevent_init_hrtimer(event);
8813 static struct pmu perf_task_clock = {
8814 .task_ctx_nr = perf_sw_context,
8816 .capabilities = PERF_PMU_CAP_NO_NMI,
8818 .event_init = task_clock_event_init,
8819 .add = task_clock_event_add,
8820 .del = task_clock_event_del,
8821 .start = task_clock_event_start,
8822 .stop = task_clock_event_stop,
8823 .read = task_clock_event_read,
8826 static void perf_pmu_nop_void(struct pmu *pmu)
8830 static void perf_pmu_nop_txn(struct pmu *pmu, unsigned int flags)
8834 static int perf_pmu_nop_int(struct pmu *pmu)
8839 static DEFINE_PER_CPU(unsigned int, nop_txn_flags);
8841 static void perf_pmu_start_txn(struct pmu *pmu, unsigned int flags)
8843 __this_cpu_write(nop_txn_flags, flags);
8845 if (flags & ~PERF_PMU_TXN_ADD)
8848 perf_pmu_disable(pmu);
8851 static int perf_pmu_commit_txn(struct pmu *pmu)
8853 unsigned int flags = __this_cpu_read(nop_txn_flags);
8855 __this_cpu_write(nop_txn_flags, 0);
8857 if (flags & ~PERF_PMU_TXN_ADD)
8860 perf_pmu_enable(pmu);
8864 static void perf_pmu_cancel_txn(struct pmu *pmu)
8866 unsigned int flags = __this_cpu_read(nop_txn_flags);
8868 __this_cpu_write(nop_txn_flags, 0);
8870 if (flags & ~PERF_PMU_TXN_ADD)
8873 perf_pmu_enable(pmu);
8876 static int perf_event_idx_default(struct perf_event *event)
8882 * Ensures all contexts with the same task_ctx_nr have the same
8883 * pmu_cpu_context too.
8885 static struct perf_cpu_context __percpu *find_pmu_context(int ctxn)
8892 list_for_each_entry(pmu, &pmus, entry) {
8893 if (pmu->task_ctx_nr == ctxn)
8894 return pmu->pmu_cpu_context;
8900 static void free_pmu_context(struct pmu *pmu)
8902 mutex_lock(&pmus_lock);
8903 free_percpu(pmu->pmu_cpu_context);
8904 mutex_unlock(&pmus_lock);
8908 * Let userspace know that this PMU supports address range filtering:
8910 static ssize_t nr_addr_filters_show(struct device *dev,
8911 struct device_attribute *attr,
8914 struct pmu *pmu = dev_get_drvdata(dev);
8916 return snprintf(page, PAGE_SIZE - 1, "%d\n", pmu->nr_addr_filters);
8918 DEVICE_ATTR_RO(nr_addr_filters);
8920 static struct idr pmu_idr;
8923 type_show(struct device *dev, struct device_attribute *attr, char *page)
8925 struct pmu *pmu = dev_get_drvdata(dev);
8927 return snprintf(page, PAGE_SIZE-1, "%d\n", pmu->type);
8929 static DEVICE_ATTR_RO(type);
8932 perf_event_mux_interval_ms_show(struct device *dev,
8933 struct device_attribute *attr,
8936 struct pmu *pmu = dev_get_drvdata(dev);
8938 return snprintf(page, PAGE_SIZE-1, "%d\n", pmu->hrtimer_interval_ms);
8941 static DEFINE_MUTEX(mux_interval_mutex);
8944 perf_event_mux_interval_ms_store(struct device *dev,
8945 struct device_attribute *attr,
8946 const char *buf, size_t count)
8948 struct pmu *pmu = dev_get_drvdata(dev);
8949 int timer, cpu, ret;
8951 ret = kstrtoint(buf, 0, &timer);
8958 /* same value, noting to do */
8959 if (timer == pmu->hrtimer_interval_ms)
8962 mutex_lock(&mux_interval_mutex);
8963 pmu->hrtimer_interval_ms = timer;
8965 /* update all cpuctx for this PMU */
8967 for_each_online_cpu(cpu) {
8968 struct perf_cpu_context *cpuctx;
8969 cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
8970 cpuctx->hrtimer_interval = ns_to_ktime(NSEC_PER_MSEC * timer);
8972 cpu_function_call(cpu,
8973 (remote_function_f)perf_mux_hrtimer_restart, cpuctx);
8976 mutex_unlock(&mux_interval_mutex);
8980 static DEVICE_ATTR_RW(perf_event_mux_interval_ms);
8982 static struct attribute *pmu_dev_attrs[] = {
8983 &dev_attr_type.attr,
8984 &dev_attr_perf_event_mux_interval_ms.attr,
8987 ATTRIBUTE_GROUPS(pmu_dev);
8989 static int pmu_bus_running;
8990 static struct bus_type pmu_bus = {
8991 .name = "event_source",
8992 .dev_groups = pmu_dev_groups,
8995 static void pmu_dev_release(struct device *dev)
9000 static int pmu_dev_alloc(struct pmu *pmu)
9004 pmu->dev = kzalloc(sizeof(struct device), GFP_KERNEL);
9008 pmu->dev->groups = pmu->attr_groups;
9009 device_initialize(pmu->dev);
9010 ret = dev_set_name(pmu->dev, "%s", pmu->name);
9014 dev_set_drvdata(pmu->dev, pmu);
9015 pmu->dev->bus = &pmu_bus;
9016 pmu->dev->release = pmu_dev_release;
9017 ret = device_add(pmu->dev);
9021 /* For PMUs with address filters, throw in an extra attribute: */
9022 if (pmu->nr_addr_filters)
9023 ret = device_create_file(pmu->dev, &dev_attr_nr_addr_filters);
9032 device_del(pmu->dev);
9035 put_device(pmu->dev);
9039 static struct lock_class_key cpuctx_mutex;
9040 static struct lock_class_key cpuctx_lock;
9042 int perf_pmu_register(struct pmu *pmu, const char *name, int type)
9046 mutex_lock(&pmus_lock);
9048 pmu->pmu_disable_count = alloc_percpu(int);
9049 if (!pmu->pmu_disable_count)
9058 type = idr_alloc(&pmu_idr, pmu, PERF_TYPE_MAX, 0, GFP_KERNEL);
9066 if (pmu_bus_running) {
9067 ret = pmu_dev_alloc(pmu);
9073 if (pmu->task_ctx_nr == perf_hw_context) {
9074 static int hw_context_taken = 0;
9077 * Other than systems with heterogeneous CPUs, it never makes
9078 * sense for two PMUs to share perf_hw_context. PMUs which are
9079 * uncore must use perf_invalid_context.
9081 if (WARN_ON_ONCE(hw_context_taken &&
9082 !(pmu->capabilities & PERF_PMU_CAP_HETEROGENEOUS_CPUS)))
9083 pmu->task_ctx_nr = perf_invalid_context;
9085 hw_context_taken = 1;
9088 pmu->pmu_cpu_context = find_pmu_context(pmu->task_ctx_nr);
9089 if (pmu->pmu_cpu_context)
9090 goto got_cpu_context;
9093 pmu->pmu_cpu_context = alloc_percpu(struct perf_cpu_context);
9094 if (!pmu->pmu_cpu_context)
9097 for_each_possible_cpu(cpu) {
9098 struct perf_cpu_context *cpuctx;
9100 cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
9101 __perf_event_init_context(&cpuctx->ctx);
9102 lockdep_set_class(&cpuctx->ctx.mutex, &cpuctx_mutex);
9103 lockdep_set_class(&cpuctx->ctx.lock, &cpuctx_lock);
9104 cpuctx->ctx.pmu = pmu;
9105 cpuctx->online = cpumask_test_cpu(cpu, perf_online_mask);
9107 __perf_mux_hrtimer_init(cpuctx, cpu);
9111 if (!pmu->start_txn) {
9112 if (pmu->pmu_enable) {
9114 * If we have pmu_enable/pmu_disable calls, install
9115 * transaction stubs that use that to try and batch
9116 * hardware accesses.
9118 pmu->start_txn = perf_pmu_start_txn;
9119 pmu->commit_txn = perf_pmu_commit_txn;
9120 pmu->cancel_txn = perf_pmu_cancel_txn;
9122 pmu->start_txn = perf_pmu_nop_txn;
9123 pmu->commit_txn = perf_pmu_nop_int;
9124 pmu->cancel_txn = perf_pmu_nop_void;
9128 if (!pmu->pmu_enable) {
9129 pmu->pmu_enable = perf_pmu_nop_void;
9130 pmu->pmu_disable = perf_pmu_nop_void;
9133 if (!pmu->event_idx)
9134 pmu->event_idx = perf_event_idx_default;
9136 list_add_rcu(&pmu->entry, &pmus);
9137 atomic_set(&pmu->exclusive_cnt, 0);
9140 mutex_unlock(&pmus_lock);
9145 device_del(pmu->dev);
9146 put_device(pmu->dev);
9149 if (pmu->type >= PERF_TYPE_MAX)
9150 idr_remove(&pmu_idr, pmu->type);
9153 free_percpu(pmu->pmu_disable_count);
9156 EXPORT_SYMBOL_GPL(perf_pmu_register);
9158 void perf_pmu_unregister(struct pmu *pmu)
9162 mutex_lock(&pmus_lock);
9163 remove_device = pmu_bus_running;
9164 list_del_rcu(&pmu->entry);
9165 mutex_unlock(&pmus_lock);
9168 * We dereference the pmu list under both SRCU and regular RCU, so
9169 * synchronize against both of those.
9171 synchronize_srcu(&pmus_srcu);
9174 free_percpu(pmu->pmu_disable_count);
9175 if (pmu->type >= PERF_TYPE_MAX)
9176 idr_remove(&pmu_idr, pmu->type);
9177 if (remove_device) {
9178 if (pmu->nr_addr_filters)
9179 device_remove_file(pmu->dev, &dev_attr_nr_addr_filters);
9180 device_del(pmu->dev);
9181 put_device(pmu->dev);
9183 free_pmu_context(pmu);
9185 EXPORT_SYMBOL_GPL(perf_pmu_unregister);
9187 static int perf_try_init_event(struct pmu *pmu, struct perf_event *event)
9189 struct perf_event_context *ctx = NULL;
9192 if (!try_module_get(pmu->module))
9195 if (event->group_leader != event) {
9197 * This ctx->mutex can nest when we're called through
9198 * inheritance. See the perf_event_ctx_lock_nested() comment.
9200 ctx = perf_event_ctx_lock_nested(event->group_leader,
9201 SINGLE_DEPTH_NESTING);
9206 ret = pmu->event_init(event);
9209 perf_event_ctx_unlock(event->group_leader, ctx);
9212 module_put(pmu->module);
9217 static struct pmu *perf_init_event(struct perf_event *event)
9223 idx = srcu_read_lock(&pmus_srcu);
9225 /* Try parent's PMU first: */
9226 if (event->parent && event->parent->pmu) {
9227 pmu = event->parent->pmu;
9228 ret = perf_try_init_event(pmu, event);
9234 pmu = idr_find(&pmu_idr, event->attr.type);
9237 ret = perf_try_init_event(pmu, event);
9243 list_for_each_entry_rcu(pmu, &pmus, entry) {
9244 ret = perf_try_init_event(pmu, event);
9248 if (ret != -ENOENT) {
9253 pmu = ERR_PTR(-ENOENT);
9255 srcu_read_unlock(&pmus_srcu, idx);
9260 static void attach_sb_event(struct perf_event *event)
9262 struct pmu_event_list *pel = per_cpu_ptr(&pmu_sb_events, event->cpu);
9264 raw_spin_lock(&pel->lock);
9265 list_add_rcu(&event->sb_list, &pel->list);
9266 raw_spin_unlock(&pel->lock);
9270 * We keep a list of all !task (and therefore per-cpu) events
9271 * that need to receive side-band records.
9273 * This avoids having to scan all the various PMU per-cpu contexts
9276 static void account_pmu_sb_event(struct perf_event *event)
9278 if (is_sb_event(event))
9279 attach_sb_event(event);
9282 static void account_event_cpu(struct perf_event *event, int cpu)
9287 if (is_cgroup_event(event))
9288 atomic_inc(&per_cpu(perf_cgroup_events, cpu));
9291 /* Freq events need the tick to stay alive (see perf_event_task_tick). */
9292 static void account_freq_event_nohz(void)
9294 #ifdef CONFIG_NO_HZ_FULL
9295 /* Lock so we don't race with concurrent unaccount */
9296 spin_lock(&nr_freq_lock);
9297 if (atomic_inc_return(&nr_freq_events) == 1)
9298 tick_nohz_dep_set(TICK_DEP_BIT_PERF_EVENTS);
9299 spin_unlock(&nr_freq_lock);
9303 static void account_freq_event(void)
9305 if (tick_nohz_full_enabled())
9306 account_freq_event_nohz();
9308 atomic_inc(&nr_freq_events);
9312 static void account_event(struct perf_event *event)
9319 if (event->attach_state & PERF_ATTACH_TASK)
9321 if (event->attr.mmap || event->attr.mmap_data)
9322 atomic_inc(&nr_mmap_events);
9323 if (event->attr.comm)
9324 atomic_inc(&nr_comm_events);
9325 if (event->attr.namespaces)
9326 atomic_inc(&nr_namespaces_events);
9327 if (event->attr.task)
9328 atomic_inc(&nr_task_events);
9329 if (event->attr.freq)
9330 account_freq_event();
9331 if (event->attr.context_switch) {
9332 atomic_inc(&nr_switch_events);
9335 if (has_branch_stack(event))
9337 if (is_cgroup_event(event))
9341 if (atomic_inc_not_zero(&perf_sched_count))
9344 mutex_lock(&perf_sched_mutex);
9345 if (!atomic_read(&perf_sched_count)) {
9346 static_branch_enable(&perf_sched_events);
9348 * Guarantee that all CPUs observe they key change and
9349 * call the perf scheduling hooks before proceeding to
9350 * install events that need them.
9352 synchronize_sched();
9355 * Now that we have waited for the sync_sched(), allow further
9356 * increments to by-pass the mutex.
9358 atomic_inc(&perf_sched_count);
9359 mutex_unlock(&perf_sched_mutex);
9363 account_event_cpu(event, event->cpu);
9365 account_pmu_sb_event(event);
9369 * Allocate and initialize a event structure
9371 static struct perf_event *
9372 perf_event_alloc(struct perf_event_attr *attr, int cpu,
9373 struct task_struct *task,
9374 struct perf_event *group_leader,
9375 struct perf_event *parent_event,
9376 perf_overflow_handler_t overflow_handler,
9377 void *context, int cgroup_fd)
9380 struct perf_event *event;
9381 struct hw_perf_event *hwc;
9384 if ((unsigned)cpu >= nr_cpu_ids) {
9385 if (!task || cpu != -1)
9386 return ERR_PTR(-EINVAL);
9389 event = kzalloc(sizeof(*event), GFP_KERNEL);
9391 return ERR_PTR(-ENOMEM);
9394 * Single events are their own group leaders, with an
9395 * empty sibling list:
9398 group_leader = event;
9400 mutex_init(&event->child_mutex);
9401 INIT_LIST_HEAD(&event->child_list);
9403 INIT_LIST_HEAD(&event->group_entry);
9404 INIT_LIST_HEAD(&event->event_entry);
9405 INIT_LIST_HEAD(&event->sibling_list);
9406 INIT_LIST_HEAD(&event->rb_entry);
9407 INIT_LIST_HEAD(&event->active_entry);
9408 INIT_LIST_HEAD(&event->addr_filters.list);
9409 INIT_HLIST_NODE(&event->hlist_entry);
9412 init_waitqueue_head(&event->waitq);
9413 init_irq_work(&event->pending, perf_pending_event);
9415 mutex_init(&event->mmap_mutex);
9416 raw_spin_lock_init(&event->addr_filters.lock);
9418 atomic_long_set(&event->refcount, 1);
9420 event->attr = *attr;
9421 event->group_leader = group_leader;
9425 event->parent = parent_event;
9427 event->ns = get_pid_ns(task_active_pid_ns(current));
9428 event->id = atomic64_inc_return(&perf_event_id);
9430 event->state = PERF_EVENT_STATE_INACTIVE;
9433 event->attach_state = PERF_ATTACH_TASK;
9435 * XXX pmu::event_init needs to know what task to account to
9436 * and we cannot use the ctx information because we need the
9437 * pmu before we get a ctx.
9439 event->hw.target = task;
9442 event->clock = &local_clock;
9444 event->clock = parent_event->clock;
9446 if (!overflow_handler && parent_event) {
9447 overflow_handler = parent_event->overflow_handler;
9448 context = parent_event->overflow_handler_context;
9449 #if defined(CONFIG_BPF_SYSCALL) && defined(CONFIG_EVENT_TRACING)
9450 if (overflow_handler == bpf_overflow_handler) {
9451 struct bpf_prog *prog = bpf_prog_inc(parent_event->prog);
9454 err = PTR_ERR(prog);
9458 event->orig_overflow_handler =
9459 parent_event->orig_overflow_handler;
9464 if (overflow_handler) {
9465 event->overflow_handler = overflow_handler;
9466 event->overflow_handler_context = context;
9467 } else if (is_write_backward(event)){
9468 event->overflow_handler = perf_event_output_backward;
9469 event->overflow_handler_context = NULL;
9471 event->overflow_handler = perf_event_output_forward;
9472 event->overflow_handler_context = NULL;
9475 perf_event__state_init(event);
9480 hwc->sample_period = attr->sample_period;
9481 if (attr->freq && attr->sample_freq)
9482 hwc->sample_period = 1;
9483 hwc->last_period = hwc->sample_period;
9485 local64_set(&hwc->period_left, hwc->sample_period);
9488 * We currently do not support PERF_SAMPLE_READ on inherited events.
9489 * See perf_output_read().
9491 if (attr->inherit && (attr->sample_type & PERF_SAMPLE_READ))
9494 if (!has_branch_stack(event))
9495 event->attr.branch_sample_type = 0;
9497 if (cgroup_fd != -1) {
9498 err = perf_cgroup_connect(cgroup_fd, event, attr, group_leader);
9503 pmu = perf_init_event(event);
9509 err = exclusive_event_init(event);
9513 if (has_addr_filter(event)) {
9514 event->addr_filters_offs = kcalloc(pmu->nr_addr_filters,
9515 sizeof(unsigned long),
9517 if (!event->addr_filters_offs) {
9522 /* force hw sync on the address filters */
9523 event->addr_filters_gen = 1;
9526 if (!event->parent) {
9527 if (event->attr.sample_type & PERF_SAMPLE_CALLCHAIN) {
9528 err = get_callchain_buffers(attr->sample_max_stack);
9530 goto err_addr_filters;
9534 /* symmetric to unaccount_event() in _free_event() */
9535 account_event(event);
9540 kfree(event->addr_filters_offs);
9543 exclusive_event_destroy(event);
9547 event->destroy(event);
9548 module_put(pmu->module);
9550 if (is_cgroup_event(event))
9551 perf_detach_cgroup(event);
9553 put_pid_ns(event->ns);
9556 return ERR_PTR(err);
9559 static int perf_copy_attr(struct perf_event_attr __user *uattr,
9560 struct perf_event_attr *attr)
9565 if (!access_ok(VERIFY_WRITE, uattr, PERF_ATTR_SIZE_VER0))
9569 * zero the full structure, so that a short copy will be nice.
9571 memset(attr, 0, sizeof(*attr));
9573 ret = get_user(size, &uattr->size);
9577 if (size > PAGE_SIZE) /* silly large */
9580 if (!size) /* abi compat */
9581 size = PERF_ATTR_SIZE_VER0;
9583 if (size < PERF_ATTR_SIZE_VER0)
9587 * If we're handed a bigger struct than we know of,
9588 * ensure all the unknown bits are 0 - i.e. new
9589 * user-space does not rely on any kernel feature
9590 * extensions we dont know about yet.
9592 if (size > sizeof(*attr)) {
9593 unsigned char __user *addr;
9594 unsigned char __user *end;
9597 addr = (void __user *)uattr + sizeof(*attr);
9598 end = (void __user *)uattr + size;
9600 for (; addr < end; addr++) {
9601 ret = get_user(val, addr);
9607 size = sizeof(*attr);
9610 ret = copy_from_user(attr, uattr, size);
9614 if (attr->__reserved_1)
9617 if (attr->sample_type & ~(PERF_SAMPLE_MAX-1))
9620 if (attr->read_format & ~(PERF_FORMAT_MAX-1))
9623 if (attr->sample_type & PERF_SAMPLE_BRANCH_STACK) {
9624 u64 mask = attr->branch_sample_type;
9626 /* only using defined bits */
9627 if (mask & ~(PERF_SAMPLE_BRANCH_MAX-1))
9630 /* at least one branch bit must be set */
9631 if (!(mask & ~PERF_SAMPLE_BRANCH_PLM_ALL))
9634 /* propagate priv level, when not set for branch */
9635 if (!(mask & PERF_SAMPLE_BRANCH_PLM_ALL)) {
9637 /* exclude_kernel checked on syscall entry */
9638 if (!attr->exclude_kernel)
9639 mask |= PERF_SAMPLE_BRANCH_KERNEL;
9641 if (!attr->exclude_user)
9642 mask |= PERF_SAMPLE_BRANCH_USER;
9644 if (!attr->exclude_hv)
9645 mask |= PERF_SAMPLE_BRANCH_HV;
9647 * adjust user setting (for HW filter setup)
9649 attr->branch_sample_type = mask;
9651 /* privileged levels capture (kernel, hv): check permissions */
9652 if ((mask & PERF_SAMPLE_BRANCH_PERM_PLM)
9653 && perf_paranoid_kernel() && !capable(CAP_SYS_ADMIN))
9657 if (attr->sample_type & PERF_SAMPLE_REGS_USER) {
9658 ret = perf_reg_validate(attr->sample_regs_user);
9663 if (attr->sample_type & PERF_SAMPLE_STACK_USER) {
9664 if (!arch_perf_have_user_stack_dump())
9668 * We have __u32 type for the size, but so far
9669 * we can only use __u16 as maximum due to the
9670 * __u16 sample size limit.
9672 if (attr->sample_stack_user >= USHRT_MAX)
9674 else if (!IS_ALIGNED(attr->sample_stack_user, sizeof(u64)))
9678 if (attr->sample_type & PERF_SAMPLE_REGS_INTR)
9679 ret = perf_reg_validate(attr->sample_regs_intr);
9684 put_user(sizeof(*attr), &uattr->size);
9690 perf_event_set_output(struct perf_event *event, struct perf_event *output_event)
9692 struct ring_buffer *rb = NULL;
9698 /* don't allow circular references */
9699 if (event == output_event)
9703 * Don't allow cross-cpu buffers
9705 if (output_event->cpu != event->cpu)
9709 * If its not a per-cpu rb, it must be the same task.
9711 if (output_event->cpu == -1 && output_event->ctx != event->ctx)
9715 * Mixing clocks in the same buffer is trouble you don't need.
9717 if (output_event->clock != event->clock)
9721 * Either writing ring buffer from beginning or from end.
9722 * Mixing is not allowed.
9724 if (is_write_backward(output_event) != is_write_backward(event))
9728 * If both events generate aux data, they must be on the same PMU
9730 if (has_aux(event) && has_aux(output_event) &&
9731 event->pmu != output_event->pmu)
9735 mutex_lock(&event->mmap_mutex);
9736 /* Can't redirect output if we've got an active mmap() */
9737 if (atomic_read(&event->mmap_count))
9741 /* get the rb we want to redirect to */
9742 rb = ring_buffer_get(output_event);
9747 ring_buffer_attach(event, rb);
9751 mutex_unlock(&event->mmap_mutex);
9757 static void mutex_lock_double(struct mutex *a, struct mutex *b)
9763 mutex_lock_nested(b, SINGLE_DEPTH_NESTING);
9766 static int perf_event_set_clock(struct perf_event *event, clockid_t clk_id)
9768 bool nmi_safe = false;
9771 case CLOCK_MONOTONIC:
9772 event->clock = &ktime_get_mono_fast_ns;
9776 case CLOCK_MONOTONIC_RAW:
9777 event->clock = &ktime_get_raw_fast_ns;
9781 case CLOCK_REALTIME:
9782 event->clock = &ktime_get_real_ns;
9785 case CLOCK_BOOTTIME:
9786 event->clock = &ktime_get_boot_ns;
9790 event->clock = &ktime_get_tai_ns;
9797 if (!nmi_safe && !(event->pmu->capabilities & PERF_PMU_CAP_NO_NMI))
9804 * Variation on perf_event_ctx_lock_nested(), except we take two context
9807 static struct perf_event_context *
9808 __perf_event_ctx_lock_double(struct perf_event *group_leader,
9809 struct perf_event_context *ctx)
9811 struct perf_event_context *gctx;
9815 gctx = READ_ONCE(group_leader->ctx);
9816 if (!atomic_inc_not_zero(&gctx->refcount)) {
9822 mutex_lock_double(&gctx->mutex, &ctx->mutex);
9824 if (group_leader->ctx != gctx) {
9825 mutex_unlock(&ctx->mutex);
9826 mutex_unlock(&gctx->mutex);
9835 * sys_perf_event_open - open a performance event, associate it to a task/cpu
9837 * @attr_uptr: event_id type attributes for monitoring/sampling
9840 * @group_fd: group leader event fd
9842 SYSCALL_DEFINE5(perf_event_open,
9843 struct perf_event_attr __user *, attr_uptr,
9844 pid_t, pid, int, cpu, int, group_fd, unsigned long, flags)
9846 struct perf_event *group_leader = NULL, *output_event = NULL;
9847 struct perf_event *event, *sibling;
9848 struct perf_event_attr attr;
9849 struct perf_event_context *ctx, *uninitialized_var(gctx);
9850 struct file *event_file = NULL;
9851 struct fd group = {NULL, 0};
9852 struct task_struct *task = NULL;
9857 int f_flags = O_RDWR;
9860 /* for future expandability... */
9861 if (flags & ~PERF_FLAG_ALL)
9864 err = perf_copy_attr(attr_uptr, &attr);
9868 if (!attr.exclude_kernel) {
9869 if (perf_paranoid_kernel() && !capable(CAP_SYS_ADMIN))
9873 if (attr.namespaces) {
9874 if (!capable(CAP_SYS_ADMIN))
9879 if (attr.sample_freq > sysctl_perf_event_sample_rate)
9882 if (attr.sample_period & (1ULL << 63))
9886 if (!attr.sample_max_stack)
9887 attr.sample_max_stack = sysctl_perf_event_max_stack;
9890 * In cgroup mode, the pid argument is used to pass the fd
9891 * opened to the cgroup directory in cgroupfs. The cpu argument
9892 * designates the cpu on which to monitor threads from that
9895 if ((flags & PERF_FLAG_PID_CGROUP) && (pid == -1 || cpu == -1))
9898 if (flags & PERF_FLAG_FD_CLOEXEC)
9899 f_flags |= O_CLOEXEC;
9901 event_fd = get_unused_fd_flags(f_flags);
9905 if (group_fd != -1) {
9906 err = perf_fget_light(group_fd, &group);
9909 group_leader = group.file->private_data;
9910 if (flags & PERF_FLAG_FD_OUTPUT)
9911 output_event = group_leader;
9912 if (flags & PERF_FLAG_FD_NO_GROUP)
9913 group_leader = NULL;
9916 if (pid != -1 && !(flags & PERF_FLAG_PID_CGROUP)) {
9917 task = find_lively_task_by_vpid(pid);
9919 err = PTR_ERR(task);
9924 if (task && group_leader &&
9925 group_leader->attr.inherit != attr.inherit) {
9931 err = mutex_lock_interruptible(&task->signal->cred_guard_mutex);
9936 * Reuse ptrace permission checks for now.
9938 * We must hold cred_guard_mutex across this and any potential
9939 * perf_install_in_context() call for this new event to
9940 * serialize against exec() altering our credentials (and the
9941 * perf_event_exit_task() that could imply).
9944 if (!ptrace_may_access(task, PTRACE_MODE_READ_REALCREDS))
9948 if (flags & PERF_FLAG_PID_CGROUP)
9951 event = perf_event_alloc(&attr, cpu, task, group_leader, NULL,
9952 NULL, NULL, cgroup_fd);
9953 if (IS_ERR(event)) {
9954 err = PTR_ERR(event);
9958 if (is_sampling_event(event)) {
9959 if (event->pmu->capabilities & PERF_PMU_CAP_NO_INTERRUPT) {
9966 * Special case software events and allow them to be part of
9967 * any hardware group.
9971 if (attr.use_clockid) {
9972 err = perf_event_set_clock(event, attr.clockid);
9977 if (pmu->task_ctx_nr == perf_sw_context)
9978 event->event_caps |= PERF_EV_CAP_SOFTWARE;
9981 (is_software_event(event) != is_software_event(group_leader))) {
9982 if (is_software_event(event)) {
9984 * If event and group_leader are not both a software
9985 * event, and event is, then group leader is not.
9987 * Allow the addition of software events to !software
9988 * groups, this is safe because software events never
9991 pmu = group_leader->pmu;
9992 } else if (is_software_event(group_leader) &&
9993 (group_leader->group_caps & PERF_EV_CAP_SOFTWARE)) {
9995 * In case the group is a pure software group, and we
9996 * try to add a hardware event, move the whole group to
9997 * the hardware context.
10004 * Get the target context (task or percpu):
10006 ctx = find_get_context(pmu, task, event);
10008 err = PTR_ERR(ctx);
10012 if ((pmu->capabilities & PERF_PMU_CAP_EXCLUSIVE) && group_leader) {
10018 * Look up the group leader (we will attach this event to it):
10020 if (group_leader) {
10024 * Do not allow a recursive hierarchy (this new sibling
10025 * becoming part of another group-sibling):
10027 if (group_leader->group_leader != group_leader)
10030 /* All events in a group should have the same clock */
10031 if (group_leader->clock != event->clock)
10035 * Do not allow to attach to a group in a different
10036 * task or CPU context:
10040 * Make sure we're both on the same task, or both
10043 if (group_leader->ctx->task != ctx->task)
10047 * Make sure we're both events for the same CPU;
10048 * grouping events for different CPUs is broken; since
10049 * you can never concurrently schedule them anyhow.
10051 if (group_leader->cpu != event->cpu)
10054 if (group_leader->ctx != ctx)
10059 * Only a group leader can be exclusive or pinned
10061 if (attr.exclusive || attr.pinned)
10065 if (output_event) {
10066 err = perf_event_set_output(event, output_event);
10071 event_file = anon_inode_getfile("[perf_event]", &perf_fops, event,
10073 if (IS_ERR(event_file)) {
10074 err = PTR_ERR(event_file);
10080 gctx = __perf_event_ctx_lock_double(group_leader, ctx);
10082 if (gctx->task == TASK_TOMBSTONE) {
10088 * Check if we raced against another sys_perf_event_open() call
10089 * moving the software group underneath us.
10091 if (!(group_leader->group_caps & PERF_EV_CAP_SOFTWARE)) {
10093 * If someone moved the group out from under us, check
10094 * if this new event wound up on the same ctx, if so
10095 * its the regular !move_group case, otherwise fail.
10101 perf_event_ctx_unlock(group_leader, gctx);
10106 mutex_lock(&ctx->mutex);
10109 if (ctx->task == TASK_TOMBSTONE) {
10114 if (!perf_event_validate_size(event)) {
10121 * Check if the @cpu we're creating an event for is online.
10123 * We use the perf_cpu_context::ctx::mutex to serialize against
10124 * the hotplug notifiers. See perf_event_{init,exit}_cpu().
10126 struct perf_cpu_context *cpuctx =
10127 container_of(ctx, struct perf_cpu_context, ctx);
10129 if (!cpuctx->online) {
10137 * Must be under the same ctx::mutex as perf_install_in_context(),
10138 * because we need to serialize with concurrent event creation.
10140 if (!exclusive_event_installable(event, ctx)) {
10141 /* exclusive and group stuff are assumed mutually exclusive */
10142 WARN_ON_ONCE(move_group);
10148 WARN_ON_ONCE(ctx->parent_ctx);
10151 * This is the point on no return; we cannot fail hereafter. This is
10152 * where we start modifying current state.
10157 * See perf_event_ctx_lock() for comments on the details
10158 * of swizzling perf_event::ctx.
10160 perf_remove_from_context(group_leader, 0);
10163 list_for_each_entry(sibling, &group_leader->sibling_list,
10165 perf_remove_from_context(sibling, 0);
10170 * Wait for everybody to stop referencing the events through
10171 * the old lists, before installing it on new lists.
10176 * Install the group siblings before the group leader.
10178 * Because a group leader will try and install the entire group
10179 * (through the sibling list, which is still in-tact), we can
10180 * end up with siblings installed in the wrong context.
10182 * By installing siblings first we NO-OP because they're not
10183 * reachable through the group lists.
10185 list_for_each_entry(sibling, &group_leader->sibling_list,
10187 perf_event__state_init(sibling);
10188 perf_install_in_context(ctx, sibling, sibling->cpu);
10193 * Removing from the context ends up with disabled
10194 * event. What we want here is event in the initial
10195 * startup state, ready to be add into new context.
10197 perf_event__state_init(group_leader);
10198 perf_install_in_context(ctx, group_leader, group_leader->cpu);
10203 * Precalculate sample_data sizes; do while holding ctx::mutex such
10204 * that we're serialized against further additions and before
10205 * perf_install_in_context() which is the point the event is active and
10206 * can use these values.
10208 perf_event__header_size(event);
10209 perf_event__id_header_size(event);
10211 event->owner = current;
10213 perf_install_in_context(ctx, event, event->cpu);
10214 perf_unpin_context(ctx);
10217 perf_event_ctx_unlock(group_leader, gctx);
10218 mutex_unlock(&ctx->mutex);
10221 mutex_unlock(&task->signal->cred_guard_mutex);
10222 put_task_struct(task);
10225 mutex_lock(¤t->perf_event_mutex);
10226 list_add_tail(&event->owner_entry, ¤t->perf_event_list);
10227 mutex_unlock(¤t->perf_event_mutex);
10230 * Drop the reference on the group_event after placing the
10231 * new event on the sibling_list. This ensures destruction
10232 * of the group leader will find the pointer to itself in
10233 * perf_group_detach().
10236 fd_install(event_fd, event_file);
10241 perf_event_ctx_unlock(group_leader, gctx);
10242 mutex_unlock(&ctx->mutex);
10246 perf_unpin_context(ctx);
10250 * If event_file is set, the fput() above will have called ->release()
10251 * and that will take care of freeing the event.
10257 mutex_unlock(&task->signal->cred_guard_mutex);
10260 put_task_struct(task);
10264 put_unused_fd(event_fd);
10269 * perf_event_create_kernel_counter
10271 * @attr: attributes of the counter to create
10272 * @cpu: cpu in which the counter is bound
10273 * @task: task to profile (NULL for percpu)
10275 struct perf_event *
10276 perf_event_create_kernel_counter(struct perf_event_attr *attr, int cpu,
10277 struct task_struct *task,
10278 perf_overflow_handler_t overflow_handler,
10281 struct perf_event_context *ctx;
10282 struct perf_event *event;
10286 * Get the target context (task or percpu):
10289 event = perf_event_alloc(attr, cpu, task, NULL, NULL,
10290 overflow_handler, context, -1);
10291 if (IS_ERR(event)) {
10292 err = PTR_ERR(event);
10296 /* Mark owner so we could distinguish it from user events. */
10297 event->owner = TASK_TOMBSTONE;
10299 ctx = find_get_context(event->pmu, task, event);
10301 err = PTR_ERR(ctx);
10305 WARN_ON_ONCE(ctx->parent_ctx);
10306 mutex_lock(&ctx->mutex);
10307 if (ctx->task == TASK_TOMBSTONE) {
10314 * Check if the @cpu we're creating an event for is online.
10316 * We use the perf_cpu_context::ctx::mutex to serialize against
10317 * the hotplug notifiers. See perf_event_{init,exit}_cpu().
10319 struct perf_cpu_context *cpuctx =
10320 container_of(ctx, struct perf_cpu_context, ctx);
10321 if (!cpuctx->online) {
10327 if (!exclusive_event_installable(event, ctx)) {
10332 perf_install_in_context(ctx, event, cpu);
10333 perf_unpin_context(ctx);
10334 mutex_unlock(&ctx->mutex);
10339 mutex_unlock(&ctx->mutex);
10340 perf_unpin_context(ctx);
10345 return ERR_PTR(err);
10347 EXPORT_SYMBOL_GPL(perf_event_create_kernel_counter);
10349 void perf_pmu_migrate_context(struct pmu *pmu, int src_cpu, int dst_cpu)
10351 struct perf_event_context *src_ctx;
10352 struct perf_event_context *dst_ctx;
10353 struct perf_event *event, *tmp;
10356 src_ctx = &per_cpu_ptr(pmu->pmu_cpu_context, src_cpu)->ctx;
10357 dst_ctx = &per_cpu_ptr(pmu->pmu_cpu_context, dst_cpu)->ctx;
10360 * See perf_event_ctx_lock() for comments on the details
10361 * of swizzling perf_event::ctx.
10363 mutex_lock_double(&src_ctx->mutex, &dst_ctx->mutex);
10364 list_for_each_entry_safe(event, tmp, &src_ctx->event_list,
10366 perf_remove_from_context(event, 0);
10367 unaccount_event_cpu(event, src_cpu);
10369 list_add(&event->migrate_entry, &events);
10373 * Wait for the events to quiesce before re-instating them.
10378 * Re-instate events in 2 passes.
10380 * Skip over group leaders and only install siblings on this first
10381 * pass, siblings will not get enabled without a leader, however a
10382 * leader will enable its siblings, even if those are still on the old
10385 list_for_each_entry_safe(event, tmp, &events, migrate_entry) {
10386 if (event->group_leader == event)
10389 list_del(&event->migrate_entry);
10390 if (event->state >= PERF_EVENT_STATE_OFF)
10391 event->state = PERF_EVENT_STATE_INACTIVE;
10392 account_event_cpu(event, dst_cpu);
10393 perf_install_in_context(dst_ctx, event, dst_cpu);
10398 * Once all the siblings are setup properly, install the group leaders
10401 list_for_each_entry_safe(event, tmp, &events, migrate_entry) {
10402 list_del(&event->migrate_entry);
10403 if (event->state >= PERF_EVENT_STATE_OFF)
10404 event->state = PERF_EVENT_STATE_INACTIVE;
10405 account_event_cpu(event, dst_cpu);
10406 perf_install_in_context(dst_ctx, event, dst_cpu);
10409 mutex_unlock(&dst_ctx->mutex);
10410 mutex_unlock(&src_ctx->mutex);
10412 EXPORT_SYMBOL_GPL(perf_pmu_migrate_context);
10414 static void sync_child_event(struct perf_event *child_event,
10415 struct task_struct *child)
10417 struct perf_event *parent_event = child_event->parent;
10420 if (child_event->attr.inherit_stat)
10421 perf_event_read_event(child_event, child);
10423 child_val = perf_event_count(child_event);
10426 * Add back the child's count to the parent's count:
10428 atomic64_add(child_val, &parent_event->child_count);
10429 atomic64_add(child_event->total_time_enabled,
10430 &parent_event->child_total_time_enabled);
10431 atomic64_add(child_event->total_time_running,
10432 &parent_event->child_total_time_running);
10436 perf_event_exit_event(struct perf_event *child_event,
10437 struct perf_event_context *child_ctx,
10438 struct task_struct *child)
10440 struct perf_event *parent_event = child_event->parent;
10443 * Do not destroy the 'original' grouping; because of the context
10444 * switch optimization the original events could've ended up in a
10445 * random child task.
10447 * If we were to destroy the original group, all group related
10448 * operations would cease to function properly after this random
10451 * Do destroy all inherited groups, we don't care about those
10452 * and being thorough is better.
10454 raw_spin_lock_irq(&child_ctx->lock);
10455 WARN_ON_ONCE(child_ctx->is_active);
10458 perf_group_detach(child_event);
10459 list_del_event(child_event, child_ctx);
10460 child_event->state = PERF_EVENT_STATE_EXIT; /* is_event_hup() */
10461 raw_spin_unlock_irq(&child_ctx->lock);
10464 * Parent events are governed by their filedesc, retain them.
10466 if (!parent_event) {
10467 perf_event_wakeup(child_event);
10471 * Child events can be cleaned up.
10474 sync_child_event(child_event, child);
10477 * Remove this event from the parent's list
10479 WARN_ON_ONCE(parent_event->ctx->parent_ctx);
10480 mutex_lock(&parent_event->child_mutex);
10481 list_del_init(&child_event->child_list);
10482 mutex_unlock(&parent_event->child_mutex);
10485 * Kick perf_poll() for is_event_hup().
10487 perf_event_wakeup(parent_event);
10488 free_event(child_event);
10489 put_event(parent_event);
10492 static void perf_event_exit_task_context(struct task_struct *child, int ctxn)
10494 struct perf_event_context *child_ctx, *clone_ctx = NULL;
10495 struct perf_event *child_event, *next;
10497 WARN_ON_ONCE(child != current);
10499 child_ctx = perf_pin_task_context(child, ctxn);
10504 * In order to reduce the amount of tricky in ctx tear-down, we hold
10505 * ctx::mutex over the entire thing. This serializes against almost
10506 * everything that wants to access the ctx.
10508 * The exception is sys_perf_event_open() /
10509 * perf_event_create_kernel_count() which does find_get_context()
10510 * without ctx::mutex (it cannot because of the move_group double mutex
10511 * lock thing). See the comments in perf_install_in_context().
10513 mutex_lock(&child_ctx->mutex);
10516 * In a single ctx::lock section, de-schedule the events and detach the
10517 * context from the task such that we cannot ever get it scheduled back
10520 raw_spin_lock_irq(&child_ctx->lock);
10521 task_ctx_sched_out(__get_cpu_context(child_ctx), child_ctx, EVENT_ALL);
10524 * Now that the context is inactive, destroy the task <-> ctx relation
10525 * and mark the context dead.
10527 RCU_INIT_POINTER(child->perf_event_ctxp[ctxn], NULL);
10528 put_ctx(child_ctx); /* cannot be last */
10529 WRITE_ONCE(child_ctx->task, TASK_TOMBSTONE);
10530 put_task_struct(current); /* cannot be last */
10532 clone_ctx = unclone_ctx(child_ctx);
10533 raw_spin_unlock_irq(&child_ctx->lock);
10536 put_ctx(clone_ctx);
10539 * Report the task dead after unscheduling the events so that we
10540 * won't get any samples after PERF_RECORD_EXIT. We can however still
10541 * get a few PERF_RECORD_READ events.
10543 perf_event_task(child, child_ctx, 0);
10545 list_for_each_entry_safe(child_event, next, &child_ctx->event_list, event_entry)
10546 perf_event_exit_event(child_event, child_ctx, child);
10548 mutex_unlock(&child_ctx->mutex);
10550 put_ctx(child_ctx);
10554 * When a child task exits, feed back event values to parent events.
10556 * Can be called with cred_guard_mutex held when called from
10557 * install_exec_creds().
10559 void perf_event_exit_task(struct task_struct *child)
10561 struct perf_event *event, *tmp;
10564 mutex_lock(&child->perf_event_mutex);
10565 list_for_each_entry_safe(event, tmp, &child->perf_event_list,
10567 list_del_init(&event->owner_entry);
10570 * Ensure the list deletion is visible before we clear
10571 * the owner, closes a race against perf_release() where
10572 * we need to serialize on the owner->perf_event_mutex.
10574 smp_store_release(&event->owner, NULL);
10576 mutex_unlock(&child->perf_event_mutex);
10578 for_each_task_context_nr(ctxn)
10579 perf_event_exit_task_context(child, ctxn);
10582 * The perf_event_exit_task_context calls perf_event_task
10583 * with child's task_ctx, which generates EXIT events for
10584 * child contexts and sets child->perf_event_ctxp[] to NULL.
10585 * At this point we need to send EXIT events to cpu contexts.
10587 perf_event_task(child, NULL, 0);
10590 static void perf_free_event(struct perf_event *event,
10591 struct perf_event_context *ctx)
10593 struct perf_event *parent = event->parent;
10595 if (WARN_ON_ONCE(!parent))
10598 mutex_lock(&parent->child_mutex);
10599 list_del_init(&event->child_list);
10600 mutex_unlock(&parent->child_mutex);
10604 raw_spin_lock_irq(&ctx->lock);
10605 perf_group_detach(event);
10606 list_del_event(event, ctx);
10607 raw_spin_unlock_irq(&ctx->lock);
10612 * Free an unexposed, unused context as created by inheritance by
10613 * perf_event_init_task below, used by fork() in case of fail.
10615 * Not all locks are strictly required, but take them anyway to be nice and
10616 * help out with the lockdep assertions.
10618 void perf_event_free_task(struct task_struct *task)
10620 struct perf_event_context *ctx;
10621 struct perf_event *event, *tmp;
10624 for_each_task_context_nr(ctxn) {
10625 ctx = task->perf_event_ctxp[ctxn];
10629 mutex_lock(&ctx->mutex);
10630 raw_spin_lock_irq(&ctx->lock);
10632 * Destroy the task <-> ctx relation and mark the context dead.
10634 * This is important because even though the task hasn't been
10635 * exposed yet the context has been (through child_list).
10637 RCU_INIT_POINTER(task->perf_event_ctxp[ctxn], NULL);
10638 WRITE_ONCE(ctx->task, TASK_TOMBSTONE);
10639 put_task_struct(task); /* cannot be last */
10640 raw_spin_unlock_irq(&ctx->lock);
10642 list_for_each_entry_safe(event, tmp, &ctx->event_list, event_entry)
10643 perf_free_event(event, ctx);
10645 mutex_unlock(&ctx->mutex);
10650 void perf_event_delayed_put(struct task_struct *task)
10654 for_each_task_context_nr(ctxn)
10655 WARN_ON_ONCE(task->perf_event_ctxp[ctxn]);
10658 struct file *perf_event_get(unsigned int fd)
10662 file = fget_raw(fd);
10664 return ERR_PTR(-EBADF);
10666 if (file->f_op != &perf_fops) {
10668 return ERR_PTR(-EBADF);
10674 const struct perf_event_attr *perf_event_attrs(struct perf_event *event)
10677 return ERR_PTR(-EINVAL);
10679 return &event->attr;
10683 * Inherit a event from parent task to child task.
10686 * - valid pointer on success
10687 * - NULL for orphaned events
10688 * - IS_ERR() on error
10690 static struct perf_event *
10691 inherit_event(struct perf_event *parent_event,
10692 struct task_struct *parent,
10693 struct perf_event_context *parent_ctx,
10694 struct task_struct *child,
10695 struct perf_event *group_leader,
10696 struct perf_event_context *child_ctx)
10698 enum perf_event_active_state parent_state = parent_event->state;
10699 struct perf_event *child_event;
10700 unsigned long flags;
10703 * Instead of creating recursive hierarchies of events,
10704 * we link inherited events back to the original parent,
10705 * which has a filp for sure, which we use as the reference
10708 if (parent_event->parent)
10709 parent_event = parent_event->parent;
10711 child_event = perf_event_alloc(&parent_event->attr,
10714 group_leader, parent_event,
10716 if (IS_ERR(child_event))
10717 return child_event;
10720 * is_orphaned_event() and list_add_tail(&parent_event->child_list)
10721 * must be under the same lock in order to serialize against
10722 * perf_event_release_kernel(), such that either we must observe
10723 * is_orphaned_event() or they will observe us on the child_list.
10725 mutex_lock(&parent_event->child_mutex);
10726 if (is_orphaned_event(parent_event) ||
10727 !atomic_long_inc_not_zero(&parent_event->refcount)) {
10728 mutex_unlock(&parent_event->child_mutex);
10729 free_event(child_event);
10733 get_ctx(child_ctx);
10736 * Make the child state follow the state of the parent event,
10737 * not its attr.disabled bit. We hold the parent's mutex,
10738 * so we won't race with perf_event_{en, dis}able_family.
10740 if (parent_state >= PERF_EVENT_STATE_INACTIVE)
10741 child_event->state = PERF_EVENT_STATE_INACTIVE;
10743 child_event->state = PERF_EVENT_STATE_OFF;
10745 if (parent_event->attr.freq) {
10746 u64 sample_period = parent_event->hw.sample_period;
10747 struct hw_perf_event *hwc = &child_event->hw;
10749 hwc->sample_period = sample_period;
10750 hwc->last_period = sample_period;
10752 local64_set(&hwc->period_left, sample_period);
10755 child_event->ctx = child_ctx;
10756 child_event->overflow_handler = parent_event->overflow_handler;
10757 child_event->overflow_handler_context
10758 = parent_event->overflow_handler_context;
10761 * Precalculate sample_data sizes
10763 perf_event__header_size(child_event);
10764 perf_event__id_header_size(child_event);
10767 * Link it up in the child's context:
10769 raw_spin_lock_irqsave(&child_ctx->lock, flags);
10770 add_event_to_ctx(child_event, child_ctx);
10771 raw_spin_unlock_irqrestore(&child_ctx->lock, flags);
10774 * Link this into the parent event's child list
10776 list_add_tail(&child_event->child_list, &parent_event->child_list);
10777 mutex_unlock(&parent_event->child_mutex);
10779 return child_event;
10783 * Inherits an event group.
10785 * This will quietly suppress orphaned events; !inherit_event() is not an error.
10786 * This matches with perf_event_release_kernel() removing all child events.
10792 static int inherit_group(struct perf_event *parent_event,
10793 struct task_struct *parent,
10794 struct perf_event_context *parent_ctx,
10795 struct task_struct *child,
10796 struct perf_event_context *child_ctx)
10798 struct perf_event *leader;
10799 struct perf_event *sub;
10800 struct perf_event *child_ctr;
10802 leader = inherit_event(parent_event, parent, parent_ctx,
10803 child, NULL, child_ctx);
10804 if (IS_ERR(leader))
10805 return PTR_ERR(leader);
10807 * @leader can be NULL here because of is_orphaned_event(). In this
10808 * case inherit_event() will create individual events, similar to what
10809 * perf_group_detach() would do anyway.
10811 list_for_each_entry(sub, &parent_event->sibling_list, group_entry) {
10812 child_ctr = inherit_event(sub, parent, parent_ctx,
10813 child, leader, child_ctx);
10814 if (IS_ERR(child_ctr))
10815 return PTR_ERR(child_ctr);
10821 * Creates the child task context and tries to inherit the event-group.
10823 * Clears @inherited_all on !attr.inherited or error. Note that we'll leave
10824 * inherited_all set when we 'fail' to inherit an orphaned event; this is
10825 * consistent with perf_event_release_kernel() removing all child events.
10832 inherit_task_group(struct perf_event *event, struct task_struct *parent,
10833 struct perf_event_context *parent_ctx,
10834 struct task_struct *child, int ctxn,
10835 int *inherited_all)
10838 struct perf_event_context *child_ctx;
10840 if (!event->attr.inherit) {
10841 *inherited_all = 0;
10845 child_ctx = child->perf_event_ctxp[ctxn];
10848 * This is executed from the parent task context, so
10849 * inherit events that have been marked for cloning.
10850 * First allocate and initialize a context for the
10853 child_ctx = alloc_perf_context(parent_ctx->pmu, child);
10857 child->perf_event_ctxp[ctxn] = child_ctx;
10860 ret = inherit_group(event, parent, parent_ctx,
10864 *inherited_all = 0;
10870 * Initialize the perf_event context in task_struct
10872 static int perf_event_init_context(struct task_struct *child, int ctxn)
10874 struct perf_event_context *child_ctx, *parent_ctx;
10875 struct perf_event_context *cloned_ctx;
10876 struct perf_event *event;
10877 struct task_struct *parent = current;
10878 int inherited_all = 1;
10879 unsigned long flags;
10882 if (likely(!parent->perf_event_ctxp[ctxn]))
10886 * If the parent's context is a clone, pin it so it won't get
10887 * swapped under us.
10889 parent_ctx = perf_pin_task_context(parent, ctxn);
10894 * No need to check if parent_ctx != NULL here; since we saw
10895 * it non-NULL earlier, the only reason for it to become NULL
10896 * is if we exit, and since we're currently in the middle of
10897 * a fork we can't be exiting at the same time.
10901 * Lock the parent list. No need to lock the child - not PID
10902 * hashed yet and not running, so nobody can access it.
10904 mutex_lock(&parent_ctx->mutex);
10907 * We dont have to disable NMIs - we are only looking at
10908 * the list, not manipulating it:
10910 list_for_each_entry(event, &parent_ctx->pinned_groups, group_entry) {
10911 ret = inherit_task_group(event, parent, parent_ctx,
10912 child, ctxn, &inherited_all);
10918 * We can't hold ctx->lock when iterating the ->flexible_group list due
10919 * to allocations, but we need to prevent rotation because
10920 * rotate_ctx() will change the list from interrupt context.
10922 raw_spin_lock_irqsave(&parent_ctx->lock, flags);
10923 parent_ctx->rotate_disable = 1;
10924 raw_spin_unlock_irqrestore(&parent_ctx->lock, flags);
10926 list_for_each_entry(event, &parent_ctx->flexible_groups, group_entry) {
10927 ret = inherit_task_group(event, parent, parent_ctx,
10928 child, ctxn, &inherited_all);
10933 raw_spin_lock_irqsave(&parent_ctx->lock, flags);
10934 parent_ctx->rotate_disable = 0;
10936 child_ctx = child->perf_event_ctxp[ctxn];
10938 if (child_ctx && inherited_all) {
10940 * Mark the child context as a clone of the parent
10941 * context, or of whatever the parent is a clone of.
10943 * Note that if the parent is a clone, the holding of
10944 * parent_ctx->lock avoids it from being uncloned.
10946 cloned_ctx = parent_ctx->parent_ctx;
10948 child_ctx->parent_ctx = cloned_ctx;
10949 child_ctx->parent_gen = parent_ctx->parent_gen;
10951 child_ctx->parent_ctx = parent_ctx;
10952 child_ctx->parent_gen = parent_ctx->generation;
10954 get_ctx(child_ctx->parent_ctx);
10957 raw_spin_unlock_irqrestore(&parent_ctx->lock, flags);
10959 mutex_unlock(&parent_ctx->mutex);
10961 perf_unpin_context(parent_ctx);
10962 put_ctx(parent_ctx);
10968 * Initialize the perf_event context in task_struct
10970 int perf_event_init_task(struct task_struct *child)
10974 memset(child->perf_event_ctxp, 0, sizeof(child->perf_event_ctxp));
10975 mutex_init(&child->perf_event_mutex);
10976 INIT_LIST_HEAD(&child->perf_event_list);
10978 for_each_task_context_nr(ctxn) {
10979 ret = perf_event_init_context(child, ctxn);
10981 perf_event_free_task(child);
10989 static void __init perf_event_init_all_cpus(void)
10991 struct swevent_htable *swhash;
10994 zalloc_cpumask_var(&perf_online_mask, GFP_KERNEL);
10996 for_each_possible_cpu(cpu) {
10997 swhash = &per_cpu(swevent_htable, cpu);
10998 mutex_init(&swhash->hlist_mutex);
10999 INIT_LIST_HEAD(&per_cpu(active_ctx_list, cpu));
11001 INIT_LIST_HEAD(&per_cpu(pmu_sb_events.list, cpu));
11002 raw_spin_lock_init(&per_cpu(pmu_sb_events.lock, cpu));
11004 #ifdef CONFIG_CGROUP_PERF
11005 INIT_LIST_HEAD(&per_cpu(cgrp_cpuctx_list, cpu));
11007 INIT_LIST_HEAD(&per_cpu(sched_cb_list, cpu));
11011 void perf_swevent_init_cpu(unsigned int cpu)
11013 struct swevent_htable *swhash = &per_cpu(swevent_htable, cpu);
11015 mutex_lock(&swhash->hlist_mutex);
11016 if (swhash->hlist_refcount > 0 && !swevent_hlist_deref(swhash)) {
11017 struct swevent_hlist *hlist;
11019 hlist = kzalloc_node(sizeof(*hlist), GFP_KERNEL, cpu_to_node(cpu));
11021 rcu_assign_pointer(swhash->swevent_hlist, hlist);
11023 mutex_unlock(&swhash->hlist_mutex);
11026 #if defined CONFIG_HOTPLUG_CPU || defined CONFIG_KEXEC_CORE
11027 static void __perf_event_exit_context(void *__info)
11029 struct perf_event_context *ctx = __info;
11030 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
11031 struct perf_event *event;
11033 raw_spin_lock(&ctx->lock);
11034 list_for_each_entry(event, &ctx->event_list, event_entry)
11035 __perf_remove_from_context(event, cpuctx, ctx, (void *)DETACH_GROUP);
11036 raw_spin_unlock(&ctx->lock);
11039 static void perf_event_exit_cpu_context(int cpu)
11041 struct perf_cpu_context *cpuctx;
11042 struct perf_event_context *ctx;
11045 mutex_lock(&pmus_lock);
11046 list_for_each_entry(pmu, &pmus, entry) {
11047 cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
11048 ctx = &cpuctx->ctx;
11050 mutex_lock(&ctx->mutex);
11051 smp_call_function_single(cpu, __perf_event_exit_context, ctx, 1);
11052 cpuctx->online = 0;
11053 mutex_unlock(&ctx->mutex);
11055 cpumask_clear_cpu(cpu, perf_online_mask);
11056 mutex_unlock(&pmus_lock);
11060 static void perf_event_exit_cpu_context(int cpu) { }
11064 int perf_event_init_cpu(unsigned int cpu)
11066 struct perf_cpu_context *cpuctx;
11067 struct perf_event_context *ctx;
11070 perf_swevent_init_cpu(cpu);
11072 mutex_lock(&pmus_lock);
11073 cpumask_set_cpu(cpu, perf_online_mask);
11074 list_for_each_entry(pmu, &pmus, entry) {
11075 cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
11076 ctx = &cpuctx->ctx;
11078 mutex_lock(&ctx->mutex);
11079 cpuctx->online = 1;
11080 mutex_unlock(&ctx->mutex);
11082 mutex_unlock(&pmus_lock);
11087 int perf_event_exit_cpu(unsigned int cpu)
11089 perf_event_exit_cpu_context(cpu);
11094 perf_reboot(struct notifier_block *notifier, unsigned long val, void *v)
11098 for_each_online_cpu(cpu)
11099 perf_event_exit_cpu(cpu);
11105 * Run the perf reboot notifier at the very last possible moment so that
11106 * the generic watchdog code runs as long as possible.
11108 static struct notifier_block perf_reboot_notifier = {
11109 .notifier_call = perf_reboot,
11110 .priority = INT_MIN,
11113 void __init perf_event_init(void)
11117 idr_init(&pmu_idr);
11119 perf_event_init_all_cpus();
11120 init_srcu_struct(&pmus_srcu);
11121 perf_pmu_register(&perf_swevent, "software", PERF_TYPE_SOFTWARE);
11122 perf_pmu_register(&perf_cpu_clock, NULL, -1);
11123 perf_pmu_register(&perf_task_clock, NULL, -1);
11124 perf_tp_register();
11125 perf_event_init_cpu(smp_processor_id());
11126 register_reboot_notifier(&perf_reboot_notifier);
11128 ret = init_hw_breakpoint();
11129 WARN(ret, "hw_breakpoint initialization failed with: %d", ret);
11132 * Build time assertion that we keep the data_head at the intended
11133 * location. IOW, validation we got the __reserved[] size right.
11135 BUILD_BUG_ON((offsetof(struct perf_event_mmap_page, data_head))
11139 ssize_t perf_event_sysfs_show(struct device *dev, struct device_attribute *attr,
11142 struct perf_pmu_events_attr *pmu_attr =
11143 container_of(attr, struct perf_pmu_events_attr, attr);
11145 if (pmu_attr->event_str)
11146 return sprintf(page, "%s\n", pmu_attr->event_str);
11150 EXPORT_SYMBOL_GPL(perf_event_sysfs_show);
11152 static int __init perf_event_sysfs_init(void)
11157 mutex_lock(&pmus_lock);
11159 ret = bus_register(&pmu_bus);
11163 list_for_each_entry(pmu, &pmus, entry) {
11164 if (!pmu->name || pmu->type < 0)
11167 ret = pmu_dev_alloc(pmu);
11168 WARN(ret, "Failed to register pmu: %s, reason %d\n", pmu->name, ret);
11170 pmu_bus_running = 1;
11174 mutex_unlock(&pmus_lock);
11178 device_initcall(perf_event_sysfs_init);
11180 #ifdef CONFIG_CGROUP_PERF
11181 static struct cgroup_subsys_state *
11182 perf_cgroup_css_alloc(struct cgroup_subsys_state *parent_css)
11184 struct perf_cgroup *jc;
11186 jc = kzalloc(sizeof(*jc), GFP_KERNEL);
11188 return ERR_PTR(-ENOMEM);
11190 jc->info = alloc_percpu(struct perf_cgroup_info);
11193 return ERR_PTR(-ENOMEM);
11199 static void perf_cgroup_css_free(struct cgroup_subsys_state *css)
11201 struct perf_cgroup *jc = container_of(css, struct perf_cgroup, css);
11203 free_percpu(jc->info);
11207 static int __perf_cgroup_move(void *info)
11209 struct task_struct *task = info;
11211 perf_cgroup_switch(task, PERF_CGROUP_SWOUT | PERF_CGROUP_SWIN);
11216 static void perf_cgroup_attach(struct cgroup_taskset *tset)
11218 struct task_struct *task;
11219 struct cgroup_subsys_state *css;
11221 cgroup_taskset_for_each(task, css, tset)
11222 task_function_call(task, __perf_cgroup_move, task);
11225 struct cgroup_subsys perf_event_cgrp_subsys = {
11226 .css_alloc = perf_cgroup_css_alloc,
11227 .css_free = perf_cgroup_css_free,
11228 .attach = perf_cgroup_attach,
11230 * Implicitly enable on dfl hierarchy so that perf events can
11231 * always be filtered by cgroup2 path as long as perf_event
11232 * controller is not mounted on a legacy hierarchy.
11234 .implicit_on_dfl = true,
11236 #endif /* CONFIG_CGROUP_PERF */