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_type(struct perf_event *event, struct task_struct *p,
1257 * only top level events have the pid namespace they were created in
1260 event = event->parent;
1262 nr = __task_pid_nr_ns(p, type, event->ns);
1263 /* avoid -1 if it is idle thread or runs in another ns */
1264 if (!nr && !pid_alive(p))
1269 static u32 perf_event_pid(struct perf_event *event, struct task_struct *p)
1271 return perf_event_pid_type(event, p, __PIDTYPE_TGID);
1274 static u32 perf_event_tid(struct perf_event *event, struct task_struct *p)
1276 return perf_event_pid_type(event, p, PIDTYPE_PID);
1280 * If we inherit events we want to return the parent event id
1283 static u64 primary_event_id(struct perf_event *event)
1288 id = event->parent->id;
1294 * Get the perf_event_context for a task and lock it.
1296 * This has to cope with with the fact that until it is locked,
1297 * the context could get moved to another task.
1299 static struct perf_event_context *
1300 perf_lock_task_context(struct task_struct *task, int ctxn, unsigned long *flags)
1302 struct perf_event_context *ctx;
1306 * One of the few rules of preemptible RCU is that one cannot do
1307 * rcu_read_unlock() while holding a scheduler (or nested) lock when
1308 * part of the read side critical section was irqs-enabled -- see
1309 * rcu_read_unlock_special().
1311 * Since ctx->lock nests under rq->lock we must ensure the entire read
1312 * side critical section has interrupts disabled.
1314 local_irq_save(*flags);
1316 ctx = rcu_dereference(task->perf_event_ctxp[ctxn]);
1319 * If this context is a clone of another, it might
1320 * get swapped for another underneath us by
1321 * perf_event_task_sched_out, though the
1322 * rcu_read_lock() protects us from any context
1323 * getting freed. Lock the context and check if it
1324 * got swapped before we could get the lock, and retry
1325 * if so. If we locked the right context, then it
1326 * can't get swapped on us any more.
1328 raw_spin_lock(&ctx->lock);
1329 if (ctx != rcu_dereference(task->perf_event_ctxp[ctxn])) {
1330 raw_spin_unlock(&ctx->lock);
1332 local_irq_restore(*flags);
1336 if (ctx->task == TASK_TOMBSTONE ||
1337 !atomic_inc_not_zero(&ctx->refcount)) {
1338 raw_spin_unlock(&ctx->lock);
1341 WARN_ON_ONCE(ctx->task != task);
1346 local_irq_restore(*flags);
1351 * Get the context for a task and increment its pin_count so it
1352 * can't get swapped to another task. This also increments its
1353 * reference count so that the context can't get freed.
1355 static struct perf_event_context *
1356 perf_pin_task_context(struct task_struct *task, int ctxn)
1358 struct perf_event_context *ctx;
1359 unsigned long flags;
1361 ctx = perf_lock_task_context(task, ctxn, &flags);
1364 raw_spin_unlock_irqrestore(&ctx->lock, flags);
1369 static void perf_unpin_context(struct perf_event_context *ctx)
1371 unsigned long flags;
1373 raw_spin_lock_irqsave(&ctx->lock, flags);
1375 raw_spin_unlock_irqrestore(&ctx->lock, flags);
1379 * Update the record of the current time in a context.
1381 static void update_context_time(struct perf_event_context *ctx)
1383 u64 now = perf_clock();
1385 ctx->time += now - ctx->timestamp;
1386 ctx->timestamp = now;
1389 static u64 perf_event_time(struct perf_event *event)
1391 struct perf_event_context *ctx = event->ctx;
1393 if (is_cgroup_event(event))
1394 return perf_cgroup_event_time(event);
1396 return ctx ? ctx->time : 0;
1400 * Update the total_time_enabled and total_time_running fields for a event.
1402 static void update_event_times(struct perf_event *event)
1404 struct perf_event_context *ctx = event->ctx;
1407 lockdep_assert_held(&ctx->lock);
1409 if (event->state < PERF_EVENT_STATE_INACTIVE ||
1410 event->group_leader->state < PERF_EVENT_STATE_INACTIVE)
1414 * in cgroup mode, time_enabled represents
1415 * the time the event was enabled AND active
1416 * tasks were in the monitored cgroup. This is
1417 * independent of the activity of the context as
1418 * there may be a mix of cgroup and non-cgroup events.
1420 * That is why we treat cgroup events differently
1423 if (is_cgroup_event(event))
1424 run_end = perf_cgroup_event_time(event);
1425 else if (ctx->is_active)
1426 run_end = ctx->time;
1428 run_end = event->tstamp_stopped;
1430 event->total_time_enabled = run_end - event->tstamp_enabled;
1432 if (event->state == PERF_EVENT_STATE_INACTIVE)
1433 run_end = event->tstamp_stopped;
1435 run_end = perf_event_time(event);
1437 event->total_time_running = run_end - event->tstamp_running;
1442 * Update total_time_enabled and total_time_running for all events in a group.
1444 static void update_group_times(struct perf_event *leader)
1446 struct perf_event *event;
1448 update_event_times(leader);
1449 list_for_each_entry(event, &leader->sibling_list, group_entry)
1450 update_event_times(event);
1453 static enum event_type_t get_event_type(struct perf_event *event)
1455 struct perf_event_context *ctx = event->ctx;
1456 enum event_type_t event_type;
1458 lockdep_assert_held(&ctx->lock);
1461 * It's 'group type', really, because if our group leader is
1462 * pinned, so are we.
1464 if (event->group_leader != event)
1465 event = event->group_leader;
1467 event_type = event->attr.pinned ? EVENT_PINNED : EVENT_FLEXIBLE;
1469 event_type |= EVENT_CPU;
1474 static struct list_head *
1475 ctx_group_list(struct perf_event *event, struct perf_event_context *ctx)
1477 if (event->attr.pinned)
1478 return &ctx->pinned_groups;
1480 return &ctx->flexible_groups;
1484 * Add a event from the lists for its context.
1485 * Must be called with ctx->mutex and ctx->lock held.
1488 list_add_event(struct perf_event *event, struct perf_event_context *ctx)
1490 lockdep_assert_held(&ctx->lock);
1492 WARN_ON_ONCE(event->attach_state & PERF_ATTACH_CONTEXT);
1493 event->attach_state |= PERF_ATTACH_CONTEXT;
1496 * If we're a stand alone event or group leader, we go to the context
1497 * list, group events are kept attached to the group so that
1498 * perf_group_detach can, at all times, locate all siblings.
1500 if (event->group_leader == event) {
1501 struct list_head *list;
1503 event->group_caps = event->event_caps;
1505 list = ctx_group_list(event, ctx);
1506 list_add_tail(&event->group_entry, list);
1509 list_update_cgroup_event(event, ctx, true);
1511 list_add_rcu(&event->event_entry, &ctx->event_list);
1513 if (event->attr.inherit_stat)
1520 * Initialize event state based on the perf_event_attr::disabled.
1522 static inline void perf_event__state_init(struct perf_event *event)
1524 event->state = event->attr.disabled ? PERF_EVENT_STATE_OFF :
1525 PERF_EVENT_STATE_INACTIVE;
1528 static void __perf_event_read_size(struct perf_event *event, int nr_siblings)
1530 int entry = sizeof(u64); /* value */
1534 if (event->attr.read_format & PERF_FORMAT_TOTAL_TIME_ENABLED)
1535 size += sizeof(u64);
1537 if (event->attr.read_format & PERF_FORMAT_TOTAL_TIME_RUNNING)
1538 size += sizeof(u64);
1540 if (event->attr.read_format & PERF_FORMAT_ID)
1541 entry += sizeof(u64);
1543 if (event->attr.read_format & PERF_FORMAT_GROUP) {
1545 size += sizeof(u64);
1549 event->read_size = size;
1552 static void __perf_event_header_size(struct perf_event *event, u64 sample_type)
1554 struct perf_sample_data *data;
1557 if (sample_type & PERF_SAMPLE_IP)
1558 size += sizeof(data->ip);
1560 if (sample_type & PERF_SAMPLE_ADDR)
1561 size += sizeof(data->addr);
1563 if (sample_type & PERF_SAMPLE_PERIOD)
1564 size += sizeof(data->period);
1566 if (sample_type & PERF_SAMPLE_WEIGHT)
1567 size += sizeof(data->weight);
1569 if (sample_type & PERF_SAMPLE_READ)
1570 size += event->read_size;
1572 if (sample_type & PERF_SAMPLE_DATA_SRC)
1573 size += sizeof(data->data_src.val);
1575 if (sample_type & PERF_SAMPLE_TRANSACTION)
1576 size += sizeof(data->txn);
1578 if (sample_type & PERF_SAMPLE_PHYS_ADDR)
1579 size += sizeof(data->phys_addr);
1581 event->header_size = size;
1585 * Called at perf_event creation and when events are attached/detached from a
1588 static void perf_event__header_size(struct perf_event *event)
1590 __perf_event_read_size(event,
1591 event->group_leader->nr_siblings);
1592 __perf_event_header_size(event, event->attr.sample_type);
1595 static void perf_event__id_header_size(struct perf_event *event)
1597 struct perf_sample_data *data;
1598 u64 sample_type = event->attr.sample_type;
1601 if (sample_type & PERF_SAMPLE_TID)
1602 size += sizeof(data->tid_entry);
1604 if (sample_type & PERF_SAMPLE_TIME)
1605 size += sizeof(data->time);
1607 if (sample_type & PERF_SAMPLE_IDENTIFIER)
1608 size += sizeof(data->id);
1610 if (sample_type & PERF_SAMPLE_ID)
1611 size += sizeof(data->id);
1613 if (sample_type & PERF_SAMPLE_STREAM_ID)
1614 size += sizeof(data->stream_id);
1616 if (sample_type & PERF_SAMPLE_CPU)
1617 size += sizeof(data->cpu_entry);
1619 event->id_header_size = size;
1622 static bool perf_event_validate_size(struct perf_event *event)
1625 * The values computed here will be over-written when we actually
1628 __perf_event_read_size(event, event->group_leader->nr_siblings + 1);
1629 __perf_event_header_size(event, event->attr.sample_type & ~PERF_SAMPLE_READ);
1630 perf_event__id_header_size(event);
1633 * Sum the lot; should not exceed the 64k limit we have on records.
1634 * Conservative limit to allow for callchains and other variable fields.
1636 if (event->read_size + event->header_size +
1637 event->id_header_size + sizeof(struct perf_event_header) >= 16*1024)
1643 static void perf_group_attach(struct perf_event *event)
1645 struct perf_event *group_leader = event->group_leader, *pos;
1647 lockdep_assert_held(&event->ctx->lock);
1650 * We can have double attach due to group movement in perf_event_open.
1652 if (event->attach_state & PERF_ATTACH_GROUP)
1655 event->attach_state |= PERF_ATTACH_GROUP;
1657 if (group_leader == event)
1660 WARN_ON_ONCE(group_leader->ctx != event->ctx);
1662 group_leader->group_caps &= event->event_caps;
1664 list_add_tail(&event->group_entry, &group_leader->sibling_list);
1665 group_leader->nr_siblings++;
1667 perf_event__header_size(group_leader);
1669 list_for_each_entry(pos, &group_leader->sibling_list, group_entry)
1670 perf_event__header_size(pos);
1674 * Remove a event from the lists for its context.
1675 * Must be called with ctx->mutex and ctx->lock held.
1678 list_del_event(struct perf_event *event, struct perf_event_context *ctx)
1680 WARN_ON_ONCE(event->ctx != ctx);
1681 lockdep_assert_held(&ctx->lock);
1684 * We can have double detach due to exit/hot-unplug + close.
1686 if (!(event->attach_state & PERF_ATTACH_CONTEXT))
1689 event->attach_state &= ~PERF_ATTACH_CONTEXT;
1691 list_update_cgroup_event(event, ctx, false);
1694 if (event->attr.inherit_stat)
1697 list_del_rcu(&event->event_entry);
1699 if (event->group_leader == event)
1700 list_del_init(&event->group_entry);
1702 update_group_times(event);
1705 * If event was in error state, then keep it
1706 * that way, otherwise bogus counts will be
1707 * returned on read(). The only way to get out
1708 * of error state is by explicit re-enabling
1711 if (event->state > PERF_EVENT_STATE_OFF)
1712 event->state = PERF_EVENT_STATE_OFF;
1717 static void perf_group_detach(struct perf_event *event)
1719 struct perf_event *sibling, *tmp;
1720 struct list_head *list = NULL;
1722 lockdep_assert_held(&event->ctx->lock);
1725 * We can have double detach due to exit/hot-unplug + close.
1727 if (!(event->attach_state & PERF_ATTACH_GROUP))
1730 event->attach_state &= ~PERF_ATTACH_GROUP;
1733 * If this is a sibling, remove it from its group.
1735 if (event->group_leader != event) {
1736 list_del_init(&event->group_entry);
1737 event->group_leader->nr_siblings--;
1741 if (!list_empty(&event->group_entry))
1742 list = &event->group_entry;
1745 * If this was a group event with sibling events then
1746 * upgrade the siblings to singleton events by adding them
1747 * to whatever list we are on.
1749 list_for_each_entry_safe(sibling, tmp, &event->sibling_list, group_entry) {
1751 list_move_tail(&sibling->group_entry, list);
1752 sibling->group_leader = sibling;
1754 /* Inherit group flags from the previous leader */
1755 sibling->group_caps = event->group_caps;
1757 WARN_ON_ONCE(sibling->ctx != event->ctx);
1761 perf_event__header_size(event->group_leader);
1763 list_for_each_entry(tmp, &event->group_leader->sibling_list, group_entry)
1764 perf_event__header_size(tmp);
1767 static bool is_orphaned_event(struct perf_event *event)
1769 return event->state == PERF_EVENT_STATE_DEAD;
1772 static inline int __pmu_filter_match(struct perf_event *event)
1774 struct pmu *pmu = event->pmu;
1775 return pmu->filter_match ? pmu->filter_match(event) : 1;
1779 * Check whether we should attempt to schedule an event group based on
1780 * PMU-specific filtering. An event group can consist of HW and SW events,
1781 * potentially with a SW leader, so we must check all the filters, to
1782 * determine whether a group is schedulable:
1784 static inline int pmu_filter_match(struct perf_event *event)
1786 struct perf_event *child;
1788 if (!__pmu_filter_match(event))
1791 list_for_each_entry(child, &event->sibling_list, group_entry) {
1792 if (!__pmu_filter_match(child))
1800 event_filter_match(struct perf_event *event)
1802 return (event->cpu == -1 || event->cpu == smp_processor_id()) &&
1803 perf_cgroup_match(event) && pmu_filter_match(event);
1807 event_sched_out(struct perf_event *event,
1808 struct perf_cpu_context *cpuctx,
1809 struct perf_event_context *ctx)
1811 u64 tstamp = perf_event_time(event);
1814 WARN_ON_ONCE(event->ctx != ctx);
1815 lockdep_assert_held(&ctx->lock);
1818 * An event which could not be activated because of
1819 * filter mismatch still needs to have its timings
1820 * maintained, otherwise bogus information is return
1821 * via read() for time_enabled, time_running:
1823 if (event->state == PERF_EVENT_STATE_INACTIVE &&
1824 !event_filter_match(event)) {
1825 delta = tstamp - event->tstamp_stopped;
1826 event->tstamp_running += delta;
1827 event->tstamp_stopped = tstamp;
1830 if (event->state != PERF_EVENT_STATE_ACTIVE)
1833 perf_pmu_disable(event->pmu);
1835 event->tstamp_stopped = tstamp;
1836 event->pmu->del(event, 0);
1838 event->state = PERF_EVENT_STATE_INACTIVE;
1839 if (event->pending_disable) {
1840 event->pending_disable = 0;
1841 event->state = PERF_EVENT_STATE_OFF;
1844 if (!is_software_event(event))
1845 cpuctx->active_oncpu--;
1846 if (!--ctx->nr_active)
1847 perf_event_ctx_deactivate(ctx);
1848 if (event->attr.freq && event->attr.sample_freq)
1850 if (event->attr.exclusive || !cpuctx->active_oncpu)
1851 cpuctx->exclusive = 0;
1853 perf_pmu_enable(event->pmu);
1857 group_sched_out(struct perf_event *group_event,
1858 struct perf_cpu_context *cpuctx,
1859 struct perf_event_context *ctx)
1861 struct perf_event *event;
1862 int state = group_event->state;
1864 perf_pmu_disable(ctx->pmu);
1866 event_sched_out(group_event, cpuctx, ctx);
1869 * Schedule out siblings (if any):
1871 list_for_each_entry(event, &group_event->sibling_list, group_entry)
1872 event_sched_out(event, cpuctx, ctx);
1874 perf_pmu_enable(ctx->pmu);
1876 if (state == PERF_EVENT_STATE_ACTIVE && group_event->attr.exclusive)
1877 cpuctx->exclusive = 0;
1880 #define DETACH_GROUP 0x01UL
1883 * Cross CPU call to remove a performance event
1885 * We disable the event on the hardware level first. After that we
1886 * remove it from the context list.
1889 __perf_remove_from_context(struct perf_event *event,
1890 struct perf_cpu_context *cpuctx,
1891 struct perf_event_context *ctx,
1894 unsigned long flags = (unsigned long)info;
1896 event_sched_out(event, cpuctx, ctx);
1897 if (flags & DETACH_GROUP)
1898 perf_group_detach(event);
1899 list_del_event(event, ctx);
1901 if (!ctx->nr_events && ctx->is_active) {
1904 WARN_ON_ONCE(cpuctx->task_ctx != ctx);
1905 cpuctx->task_ctx = NULL;
1911 * Remove the event from a task's (or a CPU's) list of events.
1913 * If event->ctx is a cloned context, callers must make sure that
1914 * every task struct that event->ctx->task could possibly point to
1915 * remains valid. This is OK when called from perf_release since
1916 * that only calls us on the top-level context, which can't be a clone.
1917 * When called from perf_event_exit_task, it's OK because the
1918 * context has been detached from its task.
1920 static void perf_remove_from_context(struct perf_event *event, unsigned long flags)
1922 struct perf_event_context *ctx = event->ctx;
1924 lockdep_assert_held(&ctx->mutex);
1926 event_function_call(event, __perf_remove_from_context, (void *)flags);
1929 * The above event_function_call() can NO-OP when it hits
1930 * TASK_TOMBSTONE. In that case we must already have been detached
1931 * from the context (by perf_event_exit_event()) but the grouping
1932 * might still be in-tact.
1934 WARN_ON_ONCE(event->attach_state & PERF_ATTACH_CONTEXT);
1935 if ((flags & DETACH_GROUP) &&
1936 (event->attach_state & PERF_ATTACH_GROUP)) {
1938 * Since in that case we cannot possibly be scheduled, simply
1941 raw_spin_lock_irq(&ctx->lock);
1942 perf_group_detach(event);
1943 raw_spin_unlock_irq(&ctx->lock);
1948 * Cross CPU call to disable a performance event
1950 static void __perf_event_disable(struct perf_event *event,
1951 struct perf_cpu_context *cpuctx,
1952 struct perf_event_context *ctx,
1955 if (event->state < PERF_EVENT_STATE_INACTIVE)
1958 update_context_time(ctx);
1959 update_cgrp_time_from_event(event);
1960 update_group_times(event);
1961 if (event == event->group_leader)
1962 group_sched_out(event, cpuctx, ctx);
1964 event_sched_out(event, cpuctx, ctx);
1965 event->state = PERF_EVENT_STATE_OFF;
1971 * If event->ctx is a cloned context, callers must make sure that
1972 * every task struct that event->ctx->task could possibly point to
1973 * remains valid. This condition is satisifed when called through
1974 * perf_event_for_each_child or perf_event_for_each because they
1975 * hold the top-level event's child_mutex, so any descendant that
1976 * goes to exit will block in perf_event_exit_event().
1978 * When called from perf_pending_event it's OK because event->ctx
1979 * is the current context on this CPU and preemption is disabled,
1980 * hence we can't get into perf_event_task_sched_out for this context.
1982 static void _perf_event_disable(struct perf_event *event)
1984 struct perf_event_context *ctx = event->ctx;
1986 raw_spin_lock_irq(&ctx->lock);
1987 if (event->state <= PERF_EVENT_STATE_OFF) {
1988 raw_spin_unlock_irq(&ctx->lock);
1991 raw_spin_unlock_irq(&ctx->lock);
1993 event_function_call(event, __perf_event_disable, NULL);
1996 void perf_event_disable_local(struct perf_event *event)
1998 event_function_local(event, __perf_event_disable, NULL);
2002 * Strictly speaking kernel users cannot create groups and therefore this
2003 * interface does not need the perf_event_ctx_lock() magic.
2005 void perf_event_disable(struct perf_event *event)
2007 struct perf_event_context *ctx;
2009 ctx = perf_event_ctx_lock(event);
2010 _perf_event_disable(event);
2011 perf_event_ctx_unlock(event, ctx);
2013 EXPORT_SYMBOL_GPL(perf_event_disable);
2015 void perf_event_disable_inatomic(struct perf_event *event)
2017 event->pending_disable = 1;
2018 irq_work_queue(&event->pending);
2021 static void perf_set_shadow_time(struct perf_event *event,
2022 struct perf_event_context *ctx,
2026 * use the correct time source for the time snapshot
2028 * We could get by without this by leveraging the
2029 * fact that to get to this function, the caller
2030 * has most likely already called update_context_time()
2031 * and update_cgrp_time_xx() and thus both timestamp
2032 * are identical (or very close). Given that tstamp is,
2033 * already adjusted for cgroup, we could say that:
2034 * tstamp - ctx->timestamp
2036 * tstamp - cgrp->timestamp.
2038 * Then, in perf_output_read(), the calculation would
2039 * work with no changes because:
2040 * - event is guaranteed scheduled in
2041 * - no scheduled out in between
2042 * - thus the timestamp would be the same
2044 * But this is a bit hairy.
2046 * So instead, we have an explicit cgroup call to remain
2047 * within the time time source all along. We believe it
2048 * is cleaner and simpler to understand.
2050 if (is_cgroup_event(event))
2051 perf_cgroup_set_shadow_time(event, tstamp);
2053 event->shadow_ctx_time = tstamp - ctx->timestamp;
2056 #define MAX_INTERRUPTS (~0ULL)
2058 static void perf_log_throttle(struct perf_event *event, int enable);
2059 static void perf_log_itrace_start(struct perf_event *event);
2062 event_sched_in(struct perf_event *event,
2063 struct perf_cpu_context *cpuctx,
2064 struct perf_event_context *ctx)
2066 u64 tstamp = perf_event_time(event);
2069 lockdep_assert_held(&ctx->lock);
2071 if (event->state <= PERF_EVENT_STATE_OFF)
2074 WRITE_ONCE(event->oncpu, smp_processor_id());
2076 * Order event::oncpu write to happen before the ACTIVE state
2080 WRITE_ONCE(event->state, PERF_EVENT_STATE_ACTIVE);
2083 * Unthrottle events, since we scheduled we might have missed several
2084 * ticks already, also for a heavily scheduling task there is little
2085 * guarantee it'll get a tick in a timely manner.
2087 if (unlikely(event->hw.interrupts == MAX_INTERRUPTS)) {
2088 perf_log_throttle(event, 1);
2089 event->hw.interrupts = 0;
2093 * The new state must be visible before we turn it on in the hardware:
2097 perf_pmu_disable(event->pmu);
2099 perf_set_shadow_time(event, ctx, tstamp);
2101 perf_log_itrace_start(event);
2103 if (event->pmu->add(event, PERF_EF_START)) {
2104 event->state = PERF_EVENT_STATE_INACTIVE;
2110 event->tstamp_running += tstamp - event->tstamp_stopped;
2112 if (!is_software_event(event))
2113 cpuctx->active_oncpu++;
2114 if (!ctx->nr_active++)
2115 perf_event_ctx_activate(ctx);
2116 if (event->attr.freq && event->attr.sample_freq)
2119 if (event->attr.exclusive)
2120 cpuctx->exclusive = 1;
2123 perf_pmu_enable(event->pmu);
2129 group_sched_in(struct perf_event *group_event,
2130 struct perf_cpu_context *cpuctx,
2131 struct perf_event_context *ctx)
2133 struct perf_event *event, *partial_group = NULL;
2134 struct pmu *pmu = ctx->pmu;
2135 u64 now = ctx->time;
2136 bool simulate = false;
2138 if (group_event->state == PERF_EVENT_STATE_OFF)
2141 pmu->start_txn(pmu, PERF_PMU_TXN_ADD);
2143 if (event_sched_in(group_event, cpuctx, ctx)) {
2144 pmu->cancel_txn(pmu);
2145 perf_mux_hrtimer_restart(cpuctx);
2150 * Schedule in siblings as one group (if any):
2152 list_for_each_entry(event, &group_event->sibling_list, group_entry) {
2153 if (event_sched_in(event, cpuctx, ctx)) {
2154 partial_group = event;
2159 if (!pmu->commit_txn(pmu))
2164 * Groups can be scheduled in as one unit only, so undo any
2165 * partial group before returning:
2166 * The events up to the failed event are scheduled out normally,
2167 * tstamp_stopped will be updated.
2169 * The failed events and the remaining siblings need to have
2170 * their timings updated as if they had gone thru event_sched_in()
2171 * and event_sched_out(). This is required to get consistent timings
2172 * across the group. This also takes care of the case where the group
2173 * could never be scheduled by ensuring tstamp_stopped is set to mark
2174 * the time the event was actually stopped, such that time delta
2175 * calculation in update_event_times() is correct.
2177 list_for_each_entry(event, &group_event->sibling_list, group_entry) {
2178 if (event == partial_group)
2182 event->tstamp_running += now - event->tstamp_stopped;
2183 event->tstamp_stopped = now;
2185 event_sched_out(event, cpuctx, ctx);
2188 event_sched_out(group_event, cpuctx, ctx);
2190 pmu->cancel_txn(pmu);
2192 perf_mux_hrtimer_restart(cpuctx);
2198 * Work out whether we can put this event group on the CPU now.
2200 static int group_can_go_on(struct perf_event *event,
2201 struct perf_cpu_context *cpuctx,
2205 * Groups consisting entirely of software events can always go on.
2207 if (event->group_caps & PERF_EV_CAP_SOFTWARE)
2210 * If an exclusive group is already on, no other hardware
2213 if (cpuctx->exclusive)
2216 * If this group is exclusive and there are already
2217 * events on the CPU, it can't go on.
2219 if (event->attr.exclusive && cpuctx->active_oncpu)
2222 * Otherwise, try to add it if all previous groups were able
2229 * Complement to update_event_times(). This computes the tstamp_* values to
2230 * continue 'enabled' state from @now, and effectively discards the time
2231 * between the prior tstamp_stopped and now (as we were in the OFF state, or
2232 * just switched (context) time base).
2234 * This further assumes '@event->state == INACTIVE' (we just came from OFF) and
2235 * cannot have been scheduled in yet. And going into INACTIVE state means
2236 * '@event->tstamp_stopped = @now'.
2238 * Thus given the rules of update_event_times():
2240 * total_time_enabled = tstamp_stopped - tstamp_enabled
2241 * total_time_running = tstamp_stopped - tstamp_running
2243 * We can insert 'tstamp_stopped == now' and reverse them to compute new
2246 static void __perf_event_enable_time(struct perf_event *event, u64 now)
2248 WARN_ON_ONCE(event->state != PERF_EVENT_STATE_INACTIVE);
2250 event->tstamp_stopped = now;
2251 event->tstamp_enabled = now - event->total_time_enabled;
2252 event->tstamp_running = now - event->total_time_running;
2255 static void add_event_to_ctx(struct perf_event *event,
2256 struct perf_event_context *ctx)
2258 u64 tstamp = perf_event_time(event);
2260 list_add_event(event, ctx);
2261 perf_group_attach(event);
2263 * We can be called with event->state == STATE_OFF when we create with
2264 * .disabled = 1. In that case the IOC_ENABLE will call this function.
2266 if (event->state == PERF_EVENT_STATE_INACTIVE)
2267 __perf_event_enable_time(event, tstamp);
2270 static void ctx_sched_out(struct perf_event_context *ctx,
2271 struct perf_cpu_context *cpuctx,
2272 enum event_type_t event_type);
2274 ctx_sched_in(struct perf_event_context *ctx,
2275 struct perf_cpu_context *cpuctx,
2276 enum event_type_t event_type,
2277 struct task_struct *task);
2279 static void task_ctx_sched_out(struct perf_cpu_context *cpuctx,
2280 struct perf_event_context *ctx,
2281 enum event_type_t event_type)
2283 if (!cpuctx->task_ctx)
2286 if (WARN_ON_ONCE(ctx != cpuctx->task_ctx))
2289 ctx_sched_out(ctx, cpuctx, event_type);
2292 static void perf_event_sched_in(struct perf_cpu_context *cpuctx,
2293 struct perf_event_context *ctx,
2294 struct task_struct *task)
2296 cpu_ctx_sched_in(cpuctx, EVENT_PINNED, task);
2298 ctx_sched_in(ctx, cpuctx, EVENT_PINNED, task);
2299 cpu_ctx_sched_in(cpuctx, EVENT_FLEXIBLE, task);
2301 ctx_sched_in(ctx, cpuctx, EVENT_FLEXIBLE, task);
2305 * We want to maintain the following priority of scheduling:
2306 * - CPU pinned (EVENT_CPU | EVENT_PINNED)
2307 * - task pinned (EVENT_PINNED)
2308 * - CPU flexible (EVENT_CPU | EVENT_FLEXIBLE)
2309 * - task flexible (EVENT_FLEXIBLE).
2311 * In order to avoid unscheduling and scheduling back in everything every
2312 * time an event is added, only do it for the groups of equal priority and
2315 * This can be called after a batch operation on task events, in which case
2316 * event_type is a bit mask of the types of events involved. For CPU events,
2317 * event_type is only either EVENT_PINNED or EVENT_FLEXIBLE.
2319 static void ctx_resched(struct perf_cpu_context *cpuctx,
2320 struct perf_event_context *task_ctx,
2321 enum event_type_t event_type)
2323 enum event_type_t ctx_event_type = event_type & EVENT_ALL;
2324 bool cpu_event = !!(event_type & EVENT_CPU);
2327 * If pinned groups are involved, flexible groups also need to be
2330 if (event_type & EVENT_PINNED)
2331 event_type |= EVENT_FLEXIBLE;
2333 perf_pmu_disable(cpuctx->ctx.pmu);
2335 task_ctx_sched_out(cpuctx, task_ctx, event_type);
2338 * Decide which cpu ctx groups to schedule out based on the types
2339 * of events that caused rescheduling:
2340 * - EVENT_CPU: schedule out corresponding groups;
2341 * - EVENT_PINNED task events: schedule out EVENT_FLEXIBLE groups;
2342 * - otherwise, do nothing more.
2345 cpu_ctx_sched_out(cpuctx, ctx_event_type);
2346 else if (ctx_event_type & EVENT_PINNED)
2347 cpu_ctx_sched_out(cpuctx, EVENT_FLEXIBLE);
2349 perf_event_sched_in(cpuctx, task_ctx, current);
2350 perf_pmu_enable(cpuctx->ctx.pmu);
2354 * Cross CPU call to install and enable a performance event
2356 * Very similar to remote_function() + event_function() but cannot assume that
2357 * things like ctx->is_active and cpuctx->task_ctx are set.
2359 static int __perf_install_in_context(void *info)
2361 struct perf_event *event = info;
2362 struct perf_event_context *ctx = event->ctx;
2363 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
2364 struct perf_event_context *task_ctx = cpuctx->task_ctx;
2365 bool reprogram = true;
2368 raw_spin_lock(&cpuctx->ctx.lock);
2370 raw_spin_lock(&ctx->lock);
2373 reprogram = (ctx->task == current);
2376 * If the task is running, it must be running on this CPU,
2377 * otherwise we cannot reprogram things.
2379 * If its not running, we don't care, ctx->lock will
2380 * serialize against it becoming runnable.
2382 if (task_curr(ctx->task) && !reprogram) {
2387 WARN_ON_ONCE(reprogram && cpuctx->task_ctx && cpuctx->task_ctx != ctx);
2388 } else if (task_ctx) {
2389 raw_spin_lock(&task_ctx->lock);
2393 ctx_sched_out(ctx, cpuctx, EVENT_TIME);
2394 add_event_to_ctx(event, ctx);
2395 ctx_resched(cpuctx, task_ctx, get_event_type(event));
2397 add_event_to_ctx(event, ctx);
2401 perf_ctx_unlock(cpuctx, task_ctx);
2407 * Attach a performance event to a context.
2409 * Very similar to event_function_call, see comment there.
2412 perf_install_in_context(struct perf_event_context *ctx,
2413 struct perf_event *event,
2416 struct task_struct *task = READ_ONCE(ctx->task);
2418 lockdep_assert_held(&ctx->mutex);
2420 if (event->cpu != -1)
2424 * Ensures that if we can observe event->ctx, both the event and ctx
2425 * will be 'complete'. See perf_iterate_sb_cpu().
2427 smp_store_release(&event->ctx, ctx);
2430 cpu_function_call(cpu, __perf_install_in_context, event);
2435 * Should not happen, we validate the ctx is still alive before calling.
2437 if (WARN_ON_ONCE(task == TASK_TOMBSTONE))
2441 * Installing events is tricky because we cannot rely on ctx->is_active
2442 * to be set in case this is the nr_events 0 -> 1 transition.
2444 * Instead we use task_curr(), which tells us if the task is running.
2445 * However, since we use task_curr() outside of rq::lock, we can race
2446 * against the actual state. This means the result can be wrong.
2448 * If we get a false positive, we retry, this is harmless.
2450 * If we get a false negative, things are complicated. If we are after
2451 * perf_event_context_sched_in() ctx::lock will serialize us, and the
2452 * value must be correct. If we're before, it doesn't matter since
2453 * perf_event_context_sched_in() will program the counter.
2455 * However, this hinges on the remote context switch having observed
2456 * our task->perf_event_ctxp[] store, such that it will in fact take
2457 * ctx::lock in perf_event_context_sched_in().
2459 * We do this by task_function_call(), if the IPI fails to hit the task
2460 * we know any future context switch of task must see the
2461 * perf_event_ctpx[] store.
2465 * This smp_mb() orders the task->perf_event_ctxp[] store with the
2466 * task_cpu() load, such that if the IPI then does not find the task
2467 * running, a future context switch of that task must observe the
2472 if (!task_function_call(task, __perf_install_in_context, event))
2475 raw_spin_lock_irq(&ctx->lock);
2477 if (WARN_ON_ONCE(task == TASK_TOMBSTONE)) {
2479 * Cannot happen because we already checked above (which also
2480 * cannot happen), and we hold ctx->mutex, which serializes us
2481 * against perf_event_exit_task_context().
2483 raw_spin_unlock_irq(&ctx->lock);
2487 * If the task is not running, ctx->lock will avoid it becoming so,
2488 * thus we can safely install the event.
2490 if (task_curr(task)) {
2491 raw_spin_unlock_irq(&ctx->lock);
2494 add_event_to_ctx(event, ctx);
2495 raw_spin_unlock_irq(&ctx->lock);
2499 * Put a event into inactive state and update time fields.
2500 * Enabling the leader of a group effectively enables all
2501 * the group members that aren't explicitly disabled, so we
2502 * have to update their ->tstamp_enabled also.
2503 * Note: this works for group members as well as group leaders
2504 * since the non-leader members' sibling_lists will be empty.
2506 static void __perf_event_mark_enabled(struct perf_event *event)
2508 struct perf_event *sub;
2509 u64 tstamp = perf_event_time(event);
2511 event->state = PERF_EVENT_STATE_INACTIVE;
2512 __perf_event_enable_time(event, tstamp);
2513 list_for_each_entry(sub, &event->sibling_list, group_entry) {
2514 /* XXX should not be > INACTIVE if event isn't */
2515 if (sub->state >= PERF_EVENT_STATE_INACTIVE)
2516 __perf_event_enable_time(sub, tstamp);
2521 * Cross CPU call to enable a performance event
2523 static void __perf_event_enable(struct perf_event *event,
2524 struct perf_cpu_context *cpuctx,
2525 struct perf_event_context *ctx,
2528 struct perf_event *leader = event->group_leader;
2529 struct perf_event_context *task_ctx;
2531 if (event->state >= PERF_EVENT_STATE_INACTIVE ||
2532 event->state <= PERF_EVENT_STATE_ERROR)
2536 ctx_sched_out(ctx, cpuctx, EVENT_TIME);
2538 __perf_event_mark_enabled(event);
2540 if (!ctx->is_active)
2543 if (!event_filter_match(event)) {
2544 if (is_cgroup_event(event))
2545 perf_cgroup_defer_enabled(event);
2546 ctx_sched_in(ctx, cpuctx, EVENT_TIME, current);
2551 * If the event is in a group and isn't the group leader,
2552 * then don't put it on unless the group is on.
2554 if (leader != event && leader->state != PERF_EVENT_STATE_ACTIVE) {
2555 ctx_sched_in(ctx, cpuctx, EVENT_TIME, current);
2559 task_ctx = cpuctx->task_ctx;
2561 WARN_ON_ONCE(task_ctx != ctx);
2563 ctx_resched(cpuctx, task_ctx, get_event_type(event));
2569 * If event->ctx is a cloned context, callers must make sure that
2570 * every task struct that event->ctx->task could possibly point to
2571 * remains valid. This condition is satisfied when called through
2572 * perf_event_for_each_child or perf_event_for_each as described
2573 * for perf_event_disable.
2575 static void _perf_event_enable(struct perf_event *event)
2577 struct perf_event_context *ctx = event->ctx;
2579 raw_spin_lock_irq(&ctx->lock);
2580 if (event->state >= PERF_EVENT_STATE_INACTIVE ||
2581 event->state < PERF_EVENT_STATE_ERROR) {
2582 raw_spin_unlock_irq(&ctx->lock);
2587 * If the event is in error state, clear that first.
2589 * That way, if we see the event in error state below, we know that it
2590 * has gone back into error state, as distinct from the task having
2591 * been scheduled away before the cross-call arrived.
2593 if (event->state == PERF_EVENT_STATE_ERROR)
2594 event->state = PERF_EVENT_STATE_OFF;
2595 raw_spin_unlock_irq(&ctx->lock);
2597 event_function_call(event, __perf_event_enable, NULL);
2601 * See perf_event_disable();
2603 void perf_event_enable(struct perf_event *event)
2605 struct perf_event_context *ctx;
2607 ctx = perf_event_ctx_lock(event);
2608 _perf_event_enable(event);
2609 perf_event_ctx_unlock(event, ctx);
2611 EXPORT_SYMBOL_GPL(perf_event_enable);
2613 struct stop_event_data {
2614 struct perf_event *event;
2615 unsigned int restart;
2618 static int __perf_event_stop(void *info)
2620 struct stop_event_data *sd = info;
2621 struct perf_event *event = sd->event;
2623 /* if it's already INACTIVE, do nothing */
2624 if (READ_ONCE(event->state) != PERF_EVENT_STATE_ACTIVE)
2627 /* matches smp_wmb() in event_sched_in() */
2631 * There is a window with interrupts enabled before we get here,
2632 * so we need to check again lest we try to stop another CPU's event.
2634 if (READ_ONCE(event->oncpu) != smp_processor_id())
2637 event->pmu->stop(event, PERF_EF_UPDATE);
2640 * May race with the actual stop (through perf_pmu_output_stop()),
2641 * but it is only used for events with AUX ring buffer, and such
2642 * events will refuse to restart because of rb::aux_mmap_count==0,
2643 * see comments in perf_aux_output_begin().
2645 * Since this is happening on a event-local CPU, no trace is lost
2649 event->pmu->start(event, 0);
2654 static int perf_event_stop(struct perf_event *event, int restart)
2656 struct stop_event_data sd = {
2663 if (READ_ONCE(event->state) != PERF_EVENT_STATE_ACTIVE)
2666 /* matches smp_wmb() in event_sched_in() */
2670 * We only want to restart ACTIVE events, so if the event goes
2671 * inactive here (event->oncpu==-1), there's nothing more to do;
2672 * fall through with ret==-ENXIO.
2674 ret = cpu_function_call(READ_ONCE(event->oncpu),
2675 __perf_event_stop, &sd);
2676 } while (ret == -EAGAIN);
2682 * In order to contain the amount of racy and tricky in the address filter
2683 * configuration management, it is a two part process:
2685 * (p1) when userspace mappings change as a result of (1) or (2) or (3) below,
2686 * we update the addresses of corresponding vmas in
2687 * event::addr_filters_offs array and bump the event::addr_filters_gen;
2688 * (p2) when an event is scheduled in (pmu::add), it calls
2689 * perf_event_addr_filters_sync() which calls pmu::addr_filters_sync()
2690 * if the generation has changed since the previous call.
2692 * If (p1) happens while the event is active, we restart it to force (p2).
2694 * (1) perf_addr_filters_apply(): adjusting filters' offsets based on
2695 * pre-existing mappings, called once when new filters arrive via SET_FILTER
2697 * (2) perf_addr_filters_adjust(): adjusting filters' offsets based on newly
2698 * registered mapping, called for every new mmap(), with mm::mmap_sem down
2700 * (3) perf_event_addr_filters_exec(): clearing filters' offsets in the process
2703 void perf_event_addr_filters_sync(struct perf_event *event)
2705 struct perf_addr_filters_head *ifh = perf_event_addr_filters(event);
2707 if (!has_addr_filter(event))
2710 raw_spin_lock(&ifh->lock);
2711 if (event->addr_filters_gen != event->hw.addr_filters_gen) {
2712 event->pmu->addr_filters_sync(event);
2713 event->hw.addr_filters_gen = event->addr_filters_gen;
2715 raw_spin_unlock(&ifh->lock);
2717 EXPORT_SYMBOL_GPL(perf_event_addr_filters_sync);
2719 static int _perf_event_refresh(struct perf_event *event, int refresh)
2722 * not supported on inherited events
2724 if (event->attr.inherit || !is_sampling_event(event))
2727 atomic_add(refresh, &event->event_limit);
2728 _perf_event_enable(event);
2734 * See perf_event_disable()
2736 int perf_event_refresh(struct perf_event *event, int refresh)
2738 struct perf_event_context *ctx;
2741 ctx = perf_event_ctx_lock(event);
2742 ret = _perf_event_refresh(event, refresh);
2743 perf_event_ctx_unlock(event, ctx);
2747 EXPORT_SYMBOL_GPL(perf_event_refresh);
2749 static void ctx_sched_out(struct perf_event_context *ctx,
2750 struct perf_cpu_context *cpuctx,
2751 enum event_type_t event_type)
2753 int is_active = ctx->is_active;
2754 struct perf_event *event;
2756 lockdep_assert_held(&ctx->lock);
2758 if (likely(!ctx->nr_events)) {
2760 * See __perf_remove_from_context().
2762 WARN_ON_ONCE(ctx->is_active);
2764 WARN_ON_ONCE(cpuctx->task_ctx);
2768 ctx->is_active &= ~event_type;
2769 if (!(ctx->is_active & EVENT_ALL))
2773 WARN_ON_ONCE(cpuctx->task_ctx != ctx);
2774 if (!ctx->is_active)
2775 cpuctx->task_ctx = NULL;
2779 * Always update time if it was set; not only when it changes.
2780 * Otherwise we can 'forget' to update time for any but the last
2781 * context we sched out. For example:
2783 * ctx_sched_out(.event_type = EVENT_FLEXIBLE)
2784 * ctx_sched_out(.event_type = EVENT_PINNED)
2786 * would only update time for the pinned events.
2788 if (is_active & EVENT_TIME) {
2789 /* update (and stop) ctx time */
2790 update_context_time(ctx);
2791 update_cgrp_time_from_cpuctx(cpuctx);
2794 is_active ^= ctx->is_active; /* changed bits */
2796 if (!ctx->nr_active || !(is_active & EVENT_ALL))
2799 perf_pmu_disable(ctx->pmu);
2800 if (is_active & EVENT_PINNED) {
2801 list_for_each_entry(event, &ctx->pinned_groups, group_entry)
2802 group_sched_out(event, cpuctx, ctx);
2805 if (is_active & EVENT_FLEXIBLE) {
2806 list_for_each_entry(event, &ctx->flexible_groups, group_entry)
2807 group_sched_out(event, cpuctx, ctx);
2809 perf_pmu_enable(ctx->pmu);
2813 * Test whether two contexts are equivalent, i.e. whether they have both been
2814 * cloned from the same version of the same context.
2816 * Equivalence is measured using a generation number in the context that is
2817 * incremented on each modification to it; see unclone_ctx(), list_add_event()
2818 * and list_del_event().
2820 static int context_equiv(struct perf_event_context *ctx1,
2821 struct perf_event_context *ctx2)
2823 lockdep_assert_held(&ctx1->lock);
2824 lockdep_assert_held(&ctx2->lock);
2826 /* Pinning disables the swap optimization */
2827 if (ctx1->pin_count || ctx2->pin_count)
2830 /* If ctx1 is the parent of ctx2 */
2831 if (ctx1 == ctx2->parent_ctx && ctx1->generation == ctx2->parent_gen)
2834 /* If ctx2 is the parent of ctx1 */
2835 if (ctx1->parent_ctx == ctx2 && ctx1->parent_gen == ctx2->generation)
2839 * If ctx1 and ctx2 have the same parent; we flatten the parent
2840 * hierarchy, see perf_event_init_context().
2842 if (ctx1->parent_ctx && ctx1->parent_ctx == ctx2->parent_ctx &&
2843 ctx1->parent_gen == ctx2->parent_gen)
2850 static void __perf_event_sync_stat(struct perf_event *event,
2851 struct perf_event *next_event)
2855 if (!event->attr.inherit_stat)
2859 * Update the event value, we cannot use perf_event_read()
2860 * because we're in the middle of a context switch and have IRQs
2861 * disabled, which upsets smp_call_function_single(), however
2862 * we know the event must be on the current CPU, therefore we
2863 * don't need to use it.
2865 switch (event->state) {
2866 case PERF_EVENT_STATE_ACTIVE:
2867 event->pmu->read(event);
2870 case PERF_EVENT_STATE_INACTIVE:
2871 update_event_times(event);
2879 * In order to keep per-task stats reliable we need to flip the event
2880 * values when we flip the contexts.
2882 value = local64_read(&next_event->count);
2883 value = local64_xchg(&event->count, value);
2884 local64_set(&next_event->count, value);
2886 swap(event->total_time_enabled, next_event->total_time_enabled);
2887 swap(event->total_time_running, next_event->total_time_running);
2890 * Since we swizzled the values, update the user visible data too.
2892 perf_event_update_userpage(event);
2893 perf_event_update_userpage(next_event);
2896 static void perf_event_sync_stat(struct perf_event_context *ctx,
2897 struct perf_event_context *next_ctx)
2899 struct perf_event *event, *next_event;
2904 update_context_time(ctx);
2906 event = list_first_entry(&ctx->event_list,
2907 struct perf_event, event_entry);
2909 next_event = list_first_entry(&next_ctx->event_list,
2910 struct perf_event, event_entry);
2912 while (&event->event_entry != &ctx->event_list &&
2913 &next_event->event_entry != &next_ctx->event_list) {
2915 __perf_event_sync_stat(event, next_event);
2917 event = list_next_entry(event, event_entry);
2918 next_event = list_next_entry(next_event, event_entry);
2922 static void perf_event_context_sched_out(struct task_struct *task, int ctxn,
2923 struct task_struct *next)
2925 struct perf_event_context *ctx = task->perf_event_ctxp[ctxn];
2926 struct perf_event_context *next_ctx;
2927 struct perf_event_context *parent, *next_parent;
2928 struct perf_cpu_context *cpuctx;
2934 cpuctx = __get_cpu_context(ctx);
2935 if (!cpuctx->task_ctx)
2939 next_ctx = next->perf_event_ctxp[ctxn];
2943 parent = rcu_dereference(ctx->parent_ctx);
2944 next_parent = rcu_dereference(next_ctx->parent_ctx);
2946 /* If neither context have a parent context; they cannot be clones. */
2947 if (!parent && !next_parent)
2950 if (next_parent == ctx || next_ctx == parent || next_parent == parent) {
2952 * Looks like the two contexts are clones, so we might be
2953 * able to optimize the context switch. We lock both
2954 * contexts and check that they are clones under the
2955 * lock (including re-checking that neither has been
2956 * uncloned in the meantime). It doesn't matter which
2957 * order we take the locks because no other cpu could
2958 * be trying to lock both of these tasks.
2960 raw_spin_lock(&ctx->lock);
2961 raw_spin_lock_nested(&next_ctx->lock, SINGLE_DEPTH_NESTING);
2962 if (context_equiv(ctx, next_ctx)) {
2963 WRITE_ONCE(ctx->task, next);
2964 WRITE_ONCE(next_ctx->task, task);
2966 swap(ctx->task_ctx_data, next_ctx->task_ctx_data);
2969 * RCU_INIT_POINTER here is safe because we've not
2970 * modified the ctx and the above modification of
2971 * ctx->task and ctx->task_ctx_data are immaterial
2972 * since those values are always verified under
2973 * ctx->lock which we're now holding.
2975 RCU_INIT_POINTER(task->perf_event_ctxp[ctxn], next_ctx);
2976 RCU_INIT_POINTER(next->perf_event_ctxp[ctxn], ctx);
2980 perf_event_sync_stat(ctx, next_ctx);
2982 raw_spin_unlock(&next_ctx->lock);
2983 raw_spin_unlock(&ctx->lock);
2989 raw_spin_lock(&ctx->lock);
2990 task_ctx_sched_out(cpuctx, ctx, EVENT_ALL);
2991 raw_spin_unlock(&ctx->lock);
2995 static DEFINE_PER_CPU(struct list_head, sched_cb_list);
2997 void perf_sched_cb_dec(struct pmu *pmu)
2999 struct perf_cpu_context *cpuctx = this_cpu_ptr(pmu->pmu_cpu_context);
3001 this_cpu_dec(perf_sched_cb_usages);
3003 if (!--cpuctx->sched_cb_usage)
3004 list_del(&cpuctx->sched_cb_entry);
3008 void perf_sched_cb_inc(struct pmu *pmu)
3010 struct perf_cpu_context *cpuctx = this_cpu_ptr(pmu->pmu_cpu_context);
3012 if (!cpuctx->sched_cb_usage++)
3013 list_add(&cpuctx->sched_cb_entry, this_cpu_ptr(&sched_cb_list));
3015 this_cpu_inc(perf_sched_cb_usages);
3019 * This function provides the context switch callback to the lower code
3020 * layer. It is invoked ONLY when the context switch callback is enabled.
3022 * This callback is relevant even to per-cpu events; for example multi event
3023 * PEBS requires this to provide PID/TID information. This requires we flush
3024 * all queued PEBS records before we context switch to a new task.
3026 static void perf_pmu_sched_task(struct task_struct *prev,
3027 struct task_struct *next,
3030 struct perf_cpu_context *cpuctx;
3036 list_for_each_entry(cpuctx, this_cpu_ptr(&sched_cb_list), sched_cb_entry) {
3037 pmu = cpuctx->ctx.pmu; /* software PMUs will not have sched_task */
3039 if (WARN_ON_ONCE(!pmu->sched_task))
3042 perf_ctx_lock(cpuctx, cpuctx->task_ctx);
3043 perf_pmu_disable(pmu);
3045 pmu->sched_task(cpuctx->task_ctx, sched_in);
3047 perf_pmu_enable(pmu);
3048 perf_ctx_unlock(cpuctx, cpuctx->task_ctx);
3052 static void perf_event_switch(struct task_struct *task,
3053 struct task_struct *next_prev, bool sched_in);
3055 #define for_each_task_context_nr(ctxn) \
3056 for ((ctxn) = 0; (ctxn) < perf_nr_task_contexts; (ctxn)++)
3059 * Called from scheduler to remove the events of the current task,
3060 * with interrupts disabled.
3062 * We stop each event and update the event value in event->count.
3064 * This does not protect us against NMI, but disable()
3065 * sets the disabled bit in the control field of event _before_
3066 * accessing the event control register. If a NMI hits, then it will
3067 * not restart the event.
3069 void __perf_event_task_sched_out(struct task_struct *task,
3070 struct task_struct *next)
3074 if (__this_cpu_read(perf_sched_cb_usages))
3075 perf_pmu_sched_task(task, next, false);
3077 if (atomic_read(&nr_switch_events))
3078 perf_event_switch(task, next, false);
3080 for_each_task_context_nr(ctxn)
3081 perf_event_context_sched_out(task, ctxn, next);
3084 * if cgroup events exist on this CPU, then we need
3085 * to check if we have to switch out PMU state.
3086 * cgroup event are system-wide mode only
3088 if (atomic_read(this_cpu_ptr(&perf_cgroup_events)))
3089 perf_cgroup_sched_out(task, next);
3093 * Called with IRQs disabled
3095 static void cpu_ctx_sched_out(struct perf_cpu_context *cpuctx,
3096 enum event_type_t event_type)
3098 ctx_sched_out(&cpuctx->ctx, cpuctx, event_type);
3102 ctx_pinned_sched_in(struct perf_event_context *ctx,
3103 struct perf_cpu_context *cpuctx)
3105 struct perf_event *event;
3107 list_for_each_entry(event, &ctx->pinned_groups, group_entry) {
3108 if (event->state <= PERF_EVENT_STATE_OFF)
3110 if (!event_filter_match(event))
3113 /* may need to reset tstamp_enabled */
3114 if (is_cgroup_event(event))
3115 perf_cgroup_mark_enabled(event, ctx);
3117 if (group_can_go_on(event, cpuctx, 1))
3118 group_sched_in(event, cpuctx, ctx);
3121 * If this pinned group hasn't been scheduled,
3122 * put it in error state.
3124 if (event->state == PERF_EVENT_STATE_INACTIVE) {
3125 update_group_times(event);
3126 event->state = PERF_EVENT_STATE_ERROR;
3132 ctx_flexible_sched_in(struct perf_event_context *ctx,
3133 struct perf_cpu_context *cpuctx)
3135 struct perf_event *event;
3138 list_for_each_entry(event, &ctx->flexible_groups, group_entry) {
3139 /* Ignore events in OFF or ERROR state */
3140 if (event->state <= PERF_EVENT_STATE_OFF)
3143 * Listen to the 'cpu' scheduling filter constraint
3146 if (!event_filter_match(event))
3149 /* may need to reset tstamp_enabled */
3150 if (is_cgroup_event(event))
3151 perf_cgroup_mark_enabled(event, ctx);
3153 if (group_can_go_on(event, cpuctx, can_add_hw)) {
3154 if (group_sched_in(event, cpuctx, ctx))
3161 ctx_sched_in(struct perf_event_context *ctx,
3162 struct perf_cpu_context *cpuctx,
3163 enum event_type_t event_type,
3164 struct task_struct *task)
3166 int is_active = ctx->is_active;
3169 lockdep_assert_held(&ctx->lock);
3171 if (likely(!ctx->nr_events))
3174 ctx->is_active |= (event_type | EVENT_TIME);
3177 cpuctx->task_ctx = ctx;
3179 WARN_ON_ONCE(cpuctx->task_ctx != ctx);
3182 is_active ^= ctx->is_active; /* changed bits */
3184 if (is_active & EVENT_TIME) {
3185 /* start ctx time */
3187 ctx->timestamp = now;
3188 perf_cgroup_set_timestamp(task, ctx);
3192 * First go through the list and put on any pinned groups
3193 * in order to give them the best chance of going on.
3195 if (is_active & EVENT_PINNED)
3196 ctx_pinned_sched_in(ctx, cpuctx);
3198 /* Then walk through the lower prio flexible groups */
3199 if (is_active & EVENT_FLEXIBLE)
3200 ctx_flexible_sched_in(ctx, cpuctx);
3203 static void cpu_ctx_sched_in(struct perf_cpu_context *cpuctx,
3204 enum event_type_t event_type,
3205 struct task_struct *task)
3207 struct perf_event_context *ctx = &cpuctx->ctx;
3209 ctx_sched_in(ctx, cpuctx, event_type, task);
3212 static void perf_event_context_sched_in(struct perf_event_context *ctx,
3213 struct task_struct *task)
3215 struct perf_cpu_context *cpuctx;
3217 cpuctx = __get_cpu_context(ctx);
3218 if (cpuctx->task_ctx == ctx)
3221 perf_ctx_lock(cpuctx, ctx);
3223 * We must check ctx->nr_events while holding ctx->lock, such
3224 * that we serialize against perf_install_in_context().
3226 if (!ctx->nr_events)
3229 perf_pmu_disable(ctx->pmu);
3231 * We want to keep the following priority order:
3232 * cpu pinned (that don't need to move), task pinned,
3233 * cpu flexible, task flexible.
3235 * However, if task's ctx is not carrying any pinned
3236 * events, no need to flip the cpuctx's events around.
3238 if (!list_empty(&ctx->pinned_groups))
3239 cpu_ctx_sched_out(cpuctx, EVENT_FLEXIBLE);
3240 perf_event_sched_in(cpuctx, ctx, task);
3241 perf_pmu_enable(ctx->pmu);
3244 perf_ctx_unlock(cpuctx, ctx);
3248 * Called from scheduler to add the events of the current task
3249 * with interrupts disabled.
3251 * We restore the event value and then enable it.
3253 * This does not protect us against NMI, but enable()
3254 * sets the enabled bit in the control field of event _before_
3255 * accessing the event control register. If a NMI hits, then it will
3256 * keep the event running.
3258 void __perf_event_task_sched_in(struct task_struct *prev,
3259 struct task_struct *task)
3261 struct perf_event_context *ctx;
3265 * If cgroup events exist on this CPU, then we need to check if we have
3266 * to switch in PMU state; cgroup event are system-wide mode only.
3268 * Since cgroup events are CPU events, we must schedule these in before
3269 * we schedule in the task events.
3271 if (atomic_read(this_cpu_ptr(&perf_cgroup_events)))
3272 perf_cgroup_sched_in(prev, task);
3274 for_each_task_context_nr(ctxn) {
3275 ctx = task->perf_event_ctxp[ctxn];
3279 perf_event_context_sched_in(ctx, task);
3282 if (atomic_read(&nr_switch_events))
3283 perf_event_switch(task, prev, true);
3285 if (__this_cpu_read(perf_sched_cb_usages))
3286 perf_pmu_sched_task(prev, task, true);
3289 static u64 perf_calculate_period(struct perf_event *event, u64 nsec, u64 count)
3291 u64 frequency = event->attr.sample_freq;
3292 u64 sec = NSEC_PER_SEC;
3293 u64 divisor, dividend;
3295 int count_fls, nsec_fls, frequency_fls, sec_fls;
3297 count_fls = fls64(count);
3298 nsec_fls = fls64(nsec);
3299 frequency_fls = fls64(frequency);
3303 * We got @count in @nsec, with a target of sample_freq HZ
3304 * the target period becomes:
3307 * period = -------------------
3308 * @nsec * sample_freq
3313 * Reduce accuracy by one bit such that @a and @b converge
3314 * to a similar magnitude.
3316 #define REDUCE_FLS(a, b) \
3318 if (a##_fls > b##_fls) { \
3328 * Reduce accuracy until either term fits in a u64, then proceed with
3329 * the other, so that finally we can do a u64/u64 division.
3331 while (count_fls + sec_fls > 64 && nsec_fls + frequency_fls > 64) {
3332 REDUCE_FLS(nsec, frequency);
3333 REDUCE_FLS(sec, count);
3336 if (count_fls + sec_fls > 64) {
3337 divisor = nsec * frequency;
3339 while (count_fls + sec_fls > 64) {
3340 REDUCE_FLS(count, sec);
3344 dividend = count * sec;
3346 dividend = count * sec;
3348 while (nsec_fls + frequency_fls > 64) {
3349 REDUCE_FLS(nsec, frequency);
3353 divisor = nsec * frequency;
3359 return div64_u64(dividend, divisor);
3362 static DEFINE_PER_CPU(int, perf_throttled_count);
3363 static DEFINE_PER_CPU(u64, perf_throttled_seq);
3365 static void perf_adjust_period(struct perf_event *event, u64 nsec, u64 count, bool disable)
3367 struct hw_perf_event *hwc = &event->hw;
3368 s64 period, sample_period;
3371 period = perf_calculate_period(event, nsec, count);
3373 delta = (s64)(period - hwc->sample_period);
3374 delta = (delta + 7) / 8; /* low pass filter */
3376 sample_period = hwc->sample_period + delta;
3381 hwc->sample_period = sample_period;
3383 if (local64_read(&hwc->period_left) > 8*sample_period) {
3385 event->pmu->stop(event, PERF_EF_UPDATE);
3387 local64_set(&hwc->period_left, 0);
3390 event->pmu->start(event, PERF_EF_RELOAD);
3395 * combine freq adjustment with unthrottling to avoid two passes over the
3396 * events. At the same time, make sure, having freq events does not change
3397 * the rate of unthrottling as that would introduce bias.
3399 static void perf_adjust_freq_unthr_context(struct perf_event_context *ctx,
3402 struct perf_event *event;
3403 struct hw_perf_event *hwc;
3404 u64 now, period = TICK_NSEC;
3408 * only need to iterate over all events iff:
3409 * - context have events in frequency mode (needs freq adjust)
3410 * - there are events to unthrottle on this cpu
3412 if (!(ctx->nr_freq || needs_unthr))
3415 raw_spin_lock(&ctx->lock);
3416 perf_pmu_disable(ctx->pmu);
3418 list_for_each_entry_rcu(event, &ctx->event_list, event_entry) {
3419 if (event->state != PERF_EVENT_STATE_ACTIVE)
3422 if (!event_filter_match(event))
3425 perf_pmu_disable(event->pmu);
3429 if (hwc->interrupts == MAX_INTERRUPTS) {
3430 hwc->interrupts = 0;
3431 perf_log_throttle(event, 1);
3432 event->pmu->start(event, 0);
3435 if (!event->attr.freq || !event->attr.sample_freq)
3439 * stop the event and update event->count
3441 event->pmu->stop(event, PERF_EF_UPDATE);
3443 now = local64_read(&event->count);
3444 delta = now - hwc->freq_count_stamp;
3445 hwc->freq_count_stamp = now;
3449 * reload only if value has changed
3450 * we have stopped the event so tell that
3451 * to perf_adjust_period() to avoid stopping it
3455 perf_adjust_period(event, period, delta, false);
3457 event->pmu->start(event, delta > 0 ? PERF_EF_RELOAD : 0);
3459 perf_pmu_enable(event->pmu);
3462 perf_pmu_enable(ctx->pmu);
3463 raw_spin_unlock(&ctx->lock);
3467 * Round-robin a context's events:
3469 static void rotate_ctx(struct perf_event_context *ctx)
3472 * Rotate the first entry last of non-pinned groups. Rotation might be
3473 * disabled by the inheritance code.
3475 if (!ctx->rotate_disable)
3476 list_rotate_left(&ctx->flexible_groups);
3479 static int perf_rotate_context(struct perf_cpu_context *cpuctx)
3481 struct perf_event_context *ctx = NULL;
3484 if (cpuctx->ctx.nr_events) {
3485 if (cpuctx->ctx.nr_events != cpuctx->ctx.nr_active)
3489 ctx = cpuctx->task_ctx;
3490 if (ctx && ctx->nr_events) {
3491 if (ctx->nr_events != ctx->nr_active)
3498 perf_ctx_lock(cpuctx, cpuctx->task_ctx);
3499 perf_pmu_disable(cpuctx->ctx.pmu);
3501 cpu_ctx_sched_out(cpuctx, EVENT_FLEXIBLE);
3503 ctx_sched_out(ctx, cpuctx, EVENT_FLEXIBLE);
3505 rotate_ctx(&cpuctx->ctx);
3509 perf_event_sched_in(cpuctx, ctx, current);
3511 perf_pmu_enable(cpuctx->ctx.pmu);
3512 perf_ctx_unlock(cpuctx, cpuctx->task_ctx);
3518 void perf_event_task_tick(void)
3520 struct list_head *head = this_cpu_ptr(&active_ctx_list);
3521 struct perf_event_context *ctx, *tmp;
3524 WARN_ON(!irqs_disabled());
3526 __this_cpu_inc(perf_throttled_seq);
3527 throttled = __this_cpu_xchg(perf_throttled_count, 0);
3528 tick_dep_clear_cpu(smp_processor_id(), TICK_DEP_BIT_PERF_EVENTS);
3530 list_for_each_entry_safe(ctx, tmp, head, active_ctx_list)
3531 perf_adjust_freq_unthr_context(ctx, throttled);
3534 static int event_enable_on_exec(struct perf_event *event,
3535 struct perf_event_context *ctx)
3537 if (!event->attr.enable_on_exec)
3540 event->attr.enable_on_exec = 0;
3541 if (event->state >= PERF_EVENT_STATE_INACTIVE)
3544 __perf_event_mark_enabled(event);
3550 * Enable all of a task's events that have been marked enable-on-exec.
3551 * This expects task == current.
3553 static void perf_event_enable_on_exec(int ctxn)
3555 struct perf_event_context *ctx, *clone_ctx = NULL;
3556 enum event_type_t event_type = 0;
3557 struct perf_cpu_context *cpuctx;
3558 struct perf_event *event;
3559 unsigned long flags;
3562 local_irq_save(flags);
3563 ctx = current->perf_event_ctxp[ctxn];
3564 if (!ctx || !ctx->nr_events)
3567 cpuctx = __get_cpu_context(ctx);
3568 perf_ctx_lock(cpuctx, ctx);
3569 ctx_sched_out(ctx, cpuctx, EVENT_TIME);
3570 list_for_each_entry(event, &ctx->event_list, event_entry) {
3571 enabled |= event_enable_on_exec(event, ctx);
3572 event_type |= get_event_type(event);
3576 * Unclone and reschedule this context if we enabled any event.
3579 clone_ctx = unclone_ctx(ctx);
3580 ctx_resched(cpuctx, ctx, event_type);
3582 ctx_sched_in(ctx, cpuctx, EVENT_TIME, current);
3584 perf_ctx_unlock(cpuctx, ctx);
3587 local_irq_restore(flags);
3593 struct perf_read_data {
3594 struct perf_event *event;
3599 static int __perf_event_read_cpu(struct perf_event *event, int event_cpu)
3601 u16 local_pkg, event_pkg;
3603 if (event->group_caps & PERF_EV_CAP_READ_ACTIVE_PKG) {
3604 int local_cpu = smp_processor_id();
3606 event_pkg = topology_physical_package_id(event_cpu);
3607 local_pkg = topology_physical_package_id(local_cpu);
3609 if (event_pkg == local_pkg)
3617 * Cross CPU call to read the hardware event
3619 static void __perf_event_read(void *info)
3621 struct perf_read_data *data = info;
3622 struct perf_event *sub, *event = data->event;
3623 struct perf_event_context *ctx = event->ctx;
3624 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
3625 struct pmu *pmu = event->pmu;
3628 * If this is a task context, we need to check whether it is
3629 * the current task context of this cpu. If not it has been
3630 * scheduled out before the smp call arrived. In that case
3631 * event->count would have been updated to a recent sample
3632 * when the event was scheduled out.
3634 if (ctx->task && cpuctx->task_ctx != ctx)
3637 raw_spin_lock(&ctx->lock);
3638 if (ctx->is_active) {
3639 update_context_time(ctx);
3640 update_cgrp_time_from_event(event);
3643 update_event_times(event);
3644 if (event->state != PERF_EVENT_STATE_ACTIVE)
3653 pmu->start_txn(pmu, PERF_PMU_TXN_READ);
3657 list_for_each_entry(sub, &event->sibling_list, group_entry) {
3658 update_event_times(sub);
3659 if (sub->state == PERF_EVENT_STATE_ACTIVE) {
3661 * Use sibling's PMU rather than @event's since
3662 * sibling could be on different (eg: software) PMU.
3664 sub->pmu->read(sub);
3668 data->ret = pmu->commit_txn(pmu);
3671 raw_spin_unlock(&ctx->lock);
3674 static inline u64 perf_event_count(struct perf_event *event)
3676 return local64_read(&event->count) + atomic64_read(&event->child_count);
3680 * NMI-safe method to read a local event, that is an event that
3682 * - either for the current task, or for this CPU
3683 * - does not have inherit set, for inherited task events
3684 * will not be local and we cannot read them atomically
3685 * - must not have a pmu::count method
3687 int perf_event_read_local(struct perf_event *event, u64 *value)
3689 unsigned long flags;
3693 * Disabling interrupts avoids all counter scheduling (context
3694 * switches, timer based rotation and IPIs).
3696 local_irq_save(flags);
3699 * It must not be an event with inherit set, we cannot read
3700 * all child counters from atomic context.
3702 if (event->attr.inherit) {
3707 /* If this is a per-task event, it must be for current */
3708 if ((event->attach_state & PERF_ATTACH_TASK) &&
3709 event->hw.target != current) {
3714 /* If this is a per-CPU event, it must be for this CPU */
3715 if (!(event->attach_state & PERF_ATTACH_TASK) &&
3716 event->cpu != smp_processor_id()) {
3722 * If the event is currently on this CPU, its either a per-task event,
3723 * or local to this CPU. Furthermore it means its ACTIVE (otherwise
3726 if (event->oncpu == smp_processor_id())
3727 event->pmu->read(event);
3729 *value = local64_read(&event->count);
3731 local_irq_restore(flags);
3736 static int perf_event_read(struct perf_event *event, bool group)
3738 int event_cpu, ret = 0;
3741 * If event is enabled and currently active on a CPU, update the
3742 * value in the event structure:
3744 if (event->state == PERF_EVENT_STATE_ACTIVE) {
3745 struct perf_read_data data = {
3751 event_cpu = READ_ONCE(event->oncpu);
3752 if ((unsigned)event_cpu >= nr_cpu_ids)
3756 event_cpu = __perf_event_read_cpu(event, event_cpu);
3759 * Purposely ignore the smp_call_function_single() return
3762 * If event_cpu isn't a valid CPU it means the event got
3763 * scheduled out and that will have updated the event count.
3765 * Therefore, either way, we'll have an up-to-date event count
3768 (void)smp_call_function_single(event_cpu, __perf_event_read, &data, 1);
3771 } else if (event->state == PERF_EVENT_STATE_INACTIVE) {
3772 struct perf_event_context *ctx = event->ctx;
3773 unsigned long flags;
3775 raw_spin_lock_irqsave(&ctx->lock, flags);
3777 * may read while context is not active
3778 * (e.g., thread is blocked), in that case
3779 * we cannot update context time
3781 if (ctx->is_active) {
3782 update_context_time(ctx);
3783 update_cgrp_time_from_event(event);
3786 update_group_times(event);
3788 update_event_times(event);
3789 raw_spin_unlock_irqrestore(&ctx->lock, flags);
3796 * Initialize the perf_event context in a task_struct:
3798 static void __perf_event_init_context(struct perf_event_context *ctx)
3800 raw_spin_lock_init(&ctx->lock);
3801 mutex_init(&ctx->mutex);
3802 INIT_LIST_HEAD(&ctx->active_ctx_list);
3803 INIT_LIST_HEAD(&ctx->pinned_groups);
3804 INIT_LIST_HEAD(&ctx->flexible_groups);
3805 INIT_LIST_HEAD(&ctx->event_list);
3806 atomic_set(&ctx->refcount, 1);
3809 static struct perf_event_context *
3810 alloc_perf_context(struct pmu *pmu, struct task_struct *task)
3812 struct perf_event_context *ctx;
3814 ctx = kzalloc(sizeof(struct perf_event_context), GFP_KERNEL);
3818 __perf_event_init_context(ctx);
3821 get_task_struct(task);
3828 static struct task_struct *
3829 find_lively_task_by_vpid(pid_t vpid)
3831 struct task_struct *task;
3837 task = find_task_by_vpid(vpid);
3839 get_task_struct(task);
3843 return ERR_PTR(-ESRCH);
3849 * Returns a matching context with refcount and pincount.
3851 static struct perf_event_context *
3852 find_get_context(struct pmu *pmu, struct task_struct *task,
3853 struct perf_event *event)
3855 struct perf_event_context *ctx, *clone_ctx = NULL;
3856 struct perf_cpu_context *cpuctx;
3857 void *task_ctx_data = NULL;
3858 unsigned long flags;
3860 int cpu = event->cpu;
3863 /* Must be root to operate on a CPU event: */
3864 if (perf_paranoid_cpu() && !capable(CAP_SYS_ADMIN))
3865 return ERR_PTR(-EACCES);
3867 cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
3876 ctxn = pmu->task_ctx_nr;
3880 if (event->attach_state & PERF_ATTACH_TASK_DATA) {
3881 task_ctx_data = kzalloc(pmu->task_ctx_size, GFP_KERNEL);
3882 if (!task_ctx_data) {
3889 ctx = perf_lock_task_context(task, ctxn, &flags);
3891 clone_ctx = unclone_ctx(ctx);
3894 if (task_ctx_data && !ctx->task_ctx_data) {
3895 ctx->task_ctx_data = task_ctx_data;
3896 task_ctx_data = NULL;
3898 raw_spin_unlock_irqrestore(&ctx->lock, flags);
3903 ctx = alloc_perf_context(pmu, task);
3908 if (task_ctx_data) {
3909 ctx->task_ctx_data = task_ctx_data;
3910 task_ctx_data = NULL;
3914 mutex_lock(&task->perf_event_mutex);
3916 * If it has already passed perf_event_exit_task().
3917 * we must see PF_EXITING, it takes this mutex too.
3919 if (task->flags & PF_EXITING)
3921 else if (task->perf_event_ctxp[ctxn])
3926 rcu_assign_pointer(task->perf_event_ctxp[ctxn], ctx);
3928 mutex_unlock(&task->perf_event_mutex);
3930 if (unlikely(err)) {
3939 kfree(task_ctx_data);
3943 kfree(task_ctx_data);
3944 return ERR_PTR(err);
3947 static void perf_event_free_filter(struct perf_event *event);
3948 static void perf_event_free_bpf_prog(struct perf_event *event);
3950 static void free_event_rcu(struct rcu_head *head)
3952 struct perf_event *event;
3954 event = container_of(head, struct perf_event, rcu_head);
3956 put_pid_ns(event->ns);
3957 perf_event_free_filter(event);
3961 static void ring_buffer_attach(struct perf_event *event,
3962 struct ring_buffer *rb);
3964 static void detach_sb_event(struct perf_event *event)
3966 struct pmu_event_list *pel = per_cpu_ptr(&pmu_sb_events, event->cpu);
3968 raw_spin_lock(&pel->lock);
3969 list_del_rcu(&event->sb_list);
3970 raw_spin_unlock(&pel->lock);
3973 static bool is_sb_event(struct perf_event *event)
3975 struct perf_event_attr *attr = &event->attr;
3980 if (event->attach_state & PERF_ATTACH_TASK)
3983 if (attr->mmap || attr->mmap_data || attr->mmap2 ||
3984 attr->comm || attr->comm_exec ||
3986 attr->context_switch)
3991 static void unaccount_pmu_sb_event(struct perf_event *event)
3993 if (is_sb_event(event))
3994 detach_sb_event(event);
3997 static void unaccount_event_cpu(struct perf_event *event, int cpu)
4002 if (is_cgroup_event(event))
4003 atomic_dec(&per_cpu(perf_cgroup_events, cpu));
4006 #ifdef CONFIG_NO_HZ_FULL
4007 static DEFINE_SPINLOCK(nr_freq_lock);
4010 static void unaccount_freq_event_nohz(void)
4012 #ifdef CONFIG_NO_HZ_FULL
4013 spin_lock(&nr_freq_lock);
4014 if (atomic_dec_and_test(&nr_freq_events))
4015 tick_nohz_dep_clear(TICK_DEP_BIT_PERF_EVENTS);
4016 spin_unlock(&nr_freq_lock);
4020 static void unaccount_freq_event(void)
4022 if (tick_nohz_full_enabled())
4023 unaccount_freq_event_nohz();
4025 atomic_dec(&nr_freq_events);
4028 static void unaccount_event(struct perf_event *event)
4035 if (event->attach_state & PERF_ATTACH_TASK)
4037 if (event->attr.mmap || event->attr.mmap_data)
4038 atomic_dec(&nr_mmap_events);
4039 if (event->attr.comm)
4040 atomic_dec(&nr_comm_events);
4041 if (event->attr.namespaces)
4042 atomic_dec(&nr_namespaces_events);
4043 if (event->attr.task)
4044 atomic_dec(&nr_task_events);
4045 if (event->attr.freq)
4046 unaccount_freq_event();
4047 if (event->attr.context_switch) {
4049 atomic_dec(&nr_switch_events);
4051 if (is_cgroup_event(event))
4053 if (has_branch_stack(event))
4057 if (!atomic_add_unless(&perf_sched_count, -1, 1))
4058 schedule_delayed_work(&perf_sched_work, HZ);
4061 unaccount_event_cpu(event, event->cpu);
4063 unaccount_pmu_sb_event(event);
4066 static void perf_sched_delayed(struct work_struct *work)
4068 mutex_lock(&perf_sched_mutex);
4069 if (atomic_dec_and_test(&perf_sched_count))
4070 static_branch_disable(&perf_sched_events);
4071 mutex_unlock(&perf_sched_mutex);
4075 * The following implement mutual exclusion of events on "exclusive" pmus
4076 * (PERF_PMU_CAP_EXCLUSIVE). Such pmus can only have one event scheduled
4077 * at a time, so we disallow creating events that might conflict, namely:
4079 * 1) cpu-wide events in the presence of per-task events,
4080 * 2) per-task events in the presence of cpu-wide events,
4081 * 3) two matching events on the same context.
4083 * The former two cases are handled in the allocation path (perf_event_alloc(),
4084 * _free_event()), the latter -- before the first perf_install_in_context().
4086 static int exclusive_event_init(struct perf_event *event)
4088 struct pmu *pmu = event->pmu;
4090 if (!(pmu->capabilities & PERF_PMU_CAP_EXCLUSIVE))
4094 * Prevent co-existence of per-task and cpu-wide events on the
4095 * same exclusive pmu.
4097 * Negative pmu::exclusive_cnt means there are cpu-wide
4098 * events on this "exclusive" pmu, positive means there are
4101 * Since this is called in perf_event_alloc() path, event::ctx
4102 * doesn't exist yet; it is, however, safe to use PERF_ATTACH_TASK
4103 * to mean "per-task event", because unlike other attach states it
4104 * never gets cleared.
4106 if (event->attach_state & PERF_ATTACH_TASK) {
4107 if (!atomic_inc_unless_negative(&pmu->exclusive_cnt))
4110 if (!atomic_dec_unless_positive(&pmu->exclusive_cnt))
4117 static void exclusive_event_destroy(struct perf_event *event)
4119 struct pmu *pmu = event->pmu;
4121 if (!(pmu->capabilities & PERF_PMU_CAP_EXCLUSIVE))
4124 /* see comment in exclusive_event_init() */
4125 if (event->attach_state & PERF_ATTACH_TASK)
4126 atomic_dec(&pmu->exclusive_cnt);
4128 atomic_inc(&pmu->exclusive_cnt);
4131 static bool exclusive_event_match(struct perf_event *e1, struct perf_event *e2)
4133 if ((e1->pmu == e2->pmu) &&
4134 (e1->cpu == e2->cpu ||
4141 /* Called under the same ctx::mutex as perf_install_in_context() */
4142 static bool exclusive_event_installable(struct perf_event *event,
4143 struct perf_event_context *ctx)
4145 struct perf_event *iter_event;
4146 struct pmu *pmu = event->pmu;
4148 if (!(pmu->capabilities & PERF_PMU_CAP_EXCLUSIVE))
4151 list_for_each_entry(iter_event, &ctx->event_list, event_entry) {
4152 if (exclusive_event_match(iter_event, event))
4159 static void perf_addr_filters_splice(struct perf_event *event,
4160 struct list_head *head);
4162 static void _free_event(struct perf_event *event)
4164 irq_work_sync(&event->pending);
4166 unaccount_event(event);
4170 * Can happen when we close an event with re-directed output.
4172 * Since we have a 0 refcount, perf_mmap_close() will skip
4173 * over us; possibly making our ring_buffer_put() the last.
4175 mutex_lock(&event->mmap_mutex);
4176 ring_buffer_attach(event, NULL);
4177 mutex_unlock(&event->mmap_mutex);
4180 if (is_cgroup_event(event))
4181 perf_detach_cgroup(event);
4183 if (!event->parent) {
4184 if (event->attr.sample_type & PERF_SAMPLE_CALLCHAIN)
4185 put_callchain_buffers();
4188 perf_event_free_bpf_prog(event);
4189 perf_addr_filters_splice(event, NULL);
4190 kfree(event->addr_filters_offs);
4193 event->destroy(event);
4196 put_ctx(event->ctx);
4198 exclusive_event_destroy(event);
4199 module_put(event->pmu->module);
4201 call_rcu(&event->rcu_head, free_event_rcu);
4205 * Used to free events which have a known refcount of 1, such as in error paths
4206 * where the event isn't exposed yet and inherited events.
4208 static void free_event(struct perf_event *event)
4210 if (WARN(atomic_long_cmpxchg(&event->refcount, 1, 0) != 1,
4211 "unexpected event refcount: %ld; ptr=%p\n",
4212 atomic_long_read(&event->refcount), event)) {
4213 /* leak to avoid use-after-free */
4221 * Remove user event from the owner task.
4223 static void perf_remove_from_owner(struct perf_event *event)
4225 struct task_struct *owner;
4229 * Matches the smp_store_release() in perf_event_exit_task(). If we
4230 * observe !owner it means the list deletion is complete and we can
4231 * indeed free this event, otherwise we need to serialize on
4232 * owner->perf_event_mutex.
4234 owner = lockless_dereference(event->owner);
4237 * Since delayed_put_task_struct() also drops the last
4238 * task reference we can safely take a new reference
4239 * while holding the rcu_read_lock().
4241 get_task_struct(owner);
4247 * If we're here through perf_event_exit_task() we're already
4248 * holding ctx->mutex which would be an inversion wrt. the
4249 * normal lock order.
4251 * However we can safely take this lock because its the child
4254 mutex_lock_nested(&owner->perf_event_mutex, SINGLE_DEPTH_NESTING);
4257 * We have to re-check the event->owner field, if it is cleared
4258 * we raced with perf_event_exit_task(), acquiring the mutex
4259 * ensured they're done, and we can proceed with freeing the
4263 list_del_init(&event->owner_entry);
4264 smp_store_release(&event->owner, NULL);
4266 mutex_unlock(&owner->perf_event_mutex);
4267 put_task_struct(owner);
4271 static void put_event(struct perf_event *event)
4273 if (!atomic_long_dec_and_test(&event->refcount))
4280 * Kill an event dead; while event:refcount will preserve the event
4281 * object, it will not preserve its functionality. Once the last 'user'
4282 * gives up the object, we'll destroy the thing.
4284 int perf_event_release_kernel(struct perf_event *event)
4286 struct perf_event_context *ctx = event->ctx;
4287 struct perf_event *child, *tmp;
4290 * If we got here through err_file: fput(event_file); we will not have
4291 * attached to a context yet.
4294 WARN_ON_ONCE(event->attach_state &
4295 (PERF_ATTACH_CONTEXT|PERF_ATTACH_GROUP));
4299 if (!is_kernel_event(event))
4300 perf_remove_from_owner(event);
4302 ctx = perf_event_ctx_lock(event);
4303 WARN_ON_ONCE(ctx->parent_ctx);
4304 perf_remove_from_context(event, DETACH_GROUP);
4306 raw_spin_lock_irq(&ctx->lock);
4308 * Mark this event as STATE_DEAD, there is no external reference to it
4311 * Anybody acquiring event->child_mutex after the below loop _must_
4312 * also see this, most importantly inherit_event() which will avoid
4313 * placing more children on the list.
4315 * Thus this guarantees that we will in fact observe and kill _ALL_
4318 event->state = PERF_EVENT_STATE_DEAD;
4319 raw_spin_unlock_irq(&ctx->lock);
4321 perf_event_ctx_unlock(event, ctx);
4324 mutex_lock(&event->child_mutex);
4325 list_for_each_entry(child, &event->child_list, child_list) {
4328 * Cannot change, child events are not migrated, see the
4329 * comment with perf_event_ctx_lock_nested().
4331 ctx = lockless_dereference(child->ctx);
4333 * Since child_mutex nests inside ctx::mutex, we must jump
4334 * through hoops. We start by grabbing a reference on the ctx.
4336 * Since the event cannot get freed while we hold the
4337 * child_mutex, the context must also exist and have a !0
4343 * Now that we have a ctx ref, we can drop child_mutex, and
4344 * acquire ctx::mutex without fear of it going away. Then we
4345 * can re-acquire child_mutex.
4347 mutex_unlock(&event->child_mutex);
4348 mutex_lock(&ctx->mutex);
4349 mutex_lock(&event->child_mutex);
4352 * Now that we hold ctx::mutex and child_mutex, revalidate our
4353 * state, if child is still the first entry, it didn't get freed
4354 * and we can continue doing so.
4356 tmp = list_first_entry_or_null(&event->child_list,
4357 struct perf_event, child_list);
4359 perf_remove_from_context(child, DETACH_GROUP);
4360 list_del(&child->child_list);
4363 * This matches the refcount bump in inherit_event();
4364 * this can't be the last reference.
4369 mutex_unlock(&event->child_mutex);
4370 mutex_unlock(&ctx->mutex);
4374 mutex_unlock(&event->child_mutex);
4377 put_event(event); /* Must be the 'last' reference */
4380 EXPORT_SYMBOL_GPL(perf_event_release_kernel);
4383 * Called when the last reference to the file is gone.
4385 static int perf_release(struct inode *inode, struct file *file)
4387 perf_event_release_kernel(file->private_data);
4391 u64 perf_event_read_value(struct perf_event *event, u64 *enabled, u64 *running)
4393 struct perf_event *child;
4399 mutex_lock(&event->child_mutex);
4401 (void)perf_event_read(event, false);
4402 total += perf_event_count(event);
4404 *enabled += event->total_time_enabled +
4405 atomic64_read(&event->child_total_time_enabled);
4406 *running += event->total_time_running +
4407 atomic64_read(&event->child_total_time_running);
4409 list_for_each_entry(child, &event->child_list, child_list) {
4410 (void)perf_event_read(child, false);
4411 total += perf_event_count(child);
4412 *enabled += child->total_time_enabled;
4413 *running += child->total_time_running;
4415 mutex_unlock(&event->child_mutex);
4419 EXPORT_SYMBOL_GPL(perf_event_read_value);
4421 static int __perf_read_group_add(struct perf_event *leader,
4422 u64 read_format, u64 *values)
4424 struct perf_event_context *ctx = leader->ctx;
4425 struct perf_event *sub;
4426 unsigned long flags;
4427 int n = 1; /* skip @nr */
4430 ret = perf_event_read(leader, true);
4435 * Since we co-schedule groups, {enabled,running} times of siblings
4436 * will be identical to those of the leader, so we only publish one
4439 if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED) {
4440 values[n++] += leader->total_time_enabled +
4441 atomic64_read(&leader->child_total_time_enabled);
4444 if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING) {
4445 values[n++] += leader->total_time_running +
4446 atomic64_read(&leader->child_total_time_running);
4450 * Write {count,id} tuples for every sibling.
4452 values[n++] += perf_event_count(leader);
4453 if (read_format & PERF_FORMAT_ID)
4454 values[n++] = primary_event_id(leader);
4456 raw_spin_lock_irqsave(&ctx->lock, flags);
4458 list_for_each_entry(sub, &leader->sibling_list, group_entry) {
4459 values[n++] += perf_event_count(sub);
4460 if (read_format & PERF_FORMAT_ID)
4461 values[n++] = primary_event_id(sub);
4464 raw_spin_unlock_irqrestore(&ctx->lock, flags);
4468 static int perf_read_group(struct perf_event *event,
4469 u64 read_format, char __user *buf)
4471 struct perf_event *leader = event->group_leader, *child;
4472 struct perf_event_context *ctx = leader->ctx;
4476 lockdep_assert_held(&ctx->mutex);
4478 values = kzalloc(event->read_size, GFP_KERNEL);
4482 values[0] = 1 + leader->nr_siblings;
4485 * By locking the child_mutex of the leader we effectively
4486 * lock the child list of all siblings.. XXX explain how.
4488 mutex_lock(&leader->child_mutex);
4490 ret = __perf_read_group_add(leader, read_format, values);
4494 list_for_each_entry(child, &leader->child_list, child_list) {
4495 ret = __perf_read_group_add(child, read_format, values);
4500 mutex_unlock(&leader->child_mutex);
4502 ret = event->read_size;
4503 if (copy_to_user(buf, values, event->read_size))
4508 mutex_unlock(&leader->child_mutex);
4514 static int perf_read_one(struct perf_event *event,
4515 u64 read_format, char __user *buf)
4517 u64 enabled, running;
4521 values[n++] = perf_event_read_value(event, &enabled, &running);
4522 if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED)
4523 values[n++] = enabled;
4524 if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING)
4525 values[n++] = running;
4526 if (read_format & PERF_FORMAT_ID)
4527 values[n++] = primary_event_id(event);
4529 if (copy_to_user(buf, values, n * sizeof(u64)))
4532 return n * sizeof(u64);
4535 static bool is_event_hup(struct perf_event *event)
4539 if (event->state > PERF_EVENT_STATE_EXIT)
4542 mutex_lock(&event->child_mutex);
4543 no_children = list_empty(&event->child_list);
4544 mutex_unlock(&event->child_mutex);
4549 * Read the performance event - simple non blocking version for now
4552 __perf_read(struct perf_event *event, char __user *buf, size_t count)
4554 u64 read_format = event->attr.read_format;
4558 * Return end-of-file for a read on a event that is in
4559 * error state (i.e. because it was pinned but it couldn't be
4560 * scheduled on to the CPU at some point).
4562 if (event->state == PERF_EVENT_STATE_ERROR)
4565 if (count < event->read_size)
4568 WARN_ON_ONCE(event->ctx->parent_ctx);
4569 if (read_format & PERF_FORMAT_GROUP)
4570 ret = perf_read_group(event, read_format, buf);
4572 ret = perf_read_one(event, read_format, buf);
4578 perf_read(struct file *file, char __user *buf, size_t count, loff_t *ppos)
4580 struct perf_event *event = file->private_data;
4581 struct perf_event_context *ctx;
4584 ctx = perf_event_ctx_lock(event);
4585 ret = __perf_read(event, buf, count);
4586 perf_event_ctx_unlock(event, ctx);
4591 static unsigned int perf_poll(struct file *file, poll_table *wait)
4593 struct perf_event *event = file->private_data;
4594 struct ring_buffer *rb;
4595 unsigned int events = POLLHUP;
4597 poll_wait(file, &event->waitq, wait);
4599 if (is_event_hup(event))
4603 * Pin the event->rb by taking event->mmap_mutex; otherwise
4604 * perf_event_set_output() can swizzle our rb and make us miss wakeups.
4606 mutex_lock(&event->mmap_mutex);
4609 events = atomic_xchg(&rb->poll, 0);
4610 mutex_unlock(&event->mmap_mutex);
4614 static void _perf_event_reset(struct perf_event *event)
4616 (void)perf_event_read(event, false);
4617 local64_set(&event->count, 0);
4618 perf_event_update_userpage(event);
4622 * Holding the top-level event's child_mutex means that any
4623 * descendant process that has inherited this event will block
4624 * in perf_event_exit_event() if it goes to exit, thus satisfying the
4625 * task existence requirements of perf_event_enable/disable.
4627 static void perf_event_for_each_child(struct perf_event *event,
4628 void (*func)(struct perf_event *))
4630 struct perf_event *child;
4632 WARN_ON_ONCE(event->ctx->parent_ctx);
4634 mutex_lock(&event->child_mutex);
4636 list_for_each_entry(child, &event->child_list, child_list)
4638 mutex_unlock(&event->child_mutex);
4641 static void perf_event_for_each(struct perf_event *event,
4642 void (*func)(struct perf_event *))
4644 struct perf_event_context *ctx = event->ctx;
4645 struct perf_event *sibling;
4647 lockdep_assert_held(&ctx->mutex);
4649 event = event->group_leader;
4651 perf_event_for_each_child(event, func);
4652 list_for_each_entry(sibling, &event->sibling_list, group_entry)
4653 perf_event_for_each_child(sibling, func);
4656 static void __perf_event_period(struct perf_event *event,
4657 struct perf_cpu_context *cpuctx,
4658 struct perf_event_context *ctx,
4661 u64 value = *((u64 *)info);
4664 if (event->attr.freq) {
4665 event->attr.sample_freq = value;
4667 event->attr.sample_period = value;
4668 event->hw.sample_period = value;
4671 active = (event->state == PERF_EVENT_STATE_ACTIVE);
4673 perf_pmu_disable(ctx->pmu);
4675 * We could be throttled; unthrottle now to avoid the tick
4676 * trying to unthrottle while we already re-started the event.
4678 if (event->hw.interrupts == MAX_INTERRUPTS) {
4679 event->hw.interrupts = 0;
4680 perf_log_throttle(event, 1);
4682 event->pmu->stop(event, PERF_EF_UPDATE);
4685 local64_set(&event->hw.period_left, 0);
4688 event->pmu->start(event, PERF_EF_RELOAD);
4689 perf_pmu_enable(ctx->pmu);
4693 static int perf_event_period(struct perf_event *event, u64 __user *arg)
4697 if (!is_sampling_event(event))
4700 if (copy_from_user(&value, arg, sizeof(value)))
4706 if (event->attr.freq && value > sysctl_perf_event_sample_rate)
4709 event_function_call(event, __perf_event_period, &value);
4714 static const struct file_operations perf_fops;
4716 static inline int perf_fget_light(int fd, struct fd *p)
4718 struct fd f = fdget(fd);
4722 if (f.file->f_op != &perf_fops) {
4730 static int perf_event_set_output(struct perf_event *event,
4731 struct perf_event *output_event);
4732 static int perf_event_set_filter(struct perf_event *event, void __user *arg);
4733 static int perf_event_set_bpf_prog(struct perf_event *event, u32 prog_fd);
4735 static long _perf_ioctl(struct perf_event *event, unsigned int cmd, unsigned long arg)
4737 void (*func)(struct perf_event *);
4741 case PERF_EVENT_IOC_ENABLE:
4742 func = _perf_event_enable;
4744 case PERF_EVENT_IOC_DISABLE:
4745 func = _perf_event_disable;
4747 case PERF_EVENT_IOC_RESET:
4748 func = _perf_event_reset;
4751 case PERF_EVENT_IOC_REFRESH:
4752 return _perf_event_refresh(event, arg);
4754 case PERF_EVENT_IOC_PERIOD:
4755 return perf_event_period(event, (u64 __user *)arg);
4757 case PERF_EVENT_IOC_ID:
4759 u64 id = primary_event_id(event);
4761 if (copy_to_user((void __user *)arg, &id, sizeof(id)))
4766 case PERF_EVENT_IOC_SET_OUTPUT:
4770 struct perf_event *output_event;
4772 ret = perf_fget_light(arg, &output);
4775 output_event = output.file->private_data;
4776 ret = perf_event_set_output(event, output_event);
4779 ret = perf_event_set_output(event, NULL);
4784 case PERF_EVENT_IOC_SET_FILTER:
4785 return perf_event_set_filter(event, (void __user *)arg);
4787 case PERF_EVENT_IOC_SET_BPF:
4788 return perf_event_set_bpf_prog(event, arg);
4790 case PERF_EVENT_IOC_PAUSE_OUTPUT: {
4791 struct ring_buffer *rb;
4794 rb = rcu_dereference(event->rb);
4795 if (!rb || !rb->nr_pages) {
4799 rb_toggle_paused(rb, !!arg);
4807 if (flags & PERF_IOC_FLAG_GROUP)
4808 perf_event_for_each(event, func);
4810 perf_event_for_each_child(event, func);
4815 static long perf_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
4817 struct perf_event *event = file->private_data;
4818 struct perf_event_context *ctx;
4821 ctx = perf_event_ctx_lock(event);
4822 ret = _perf_ioctl(event, cmd, arg);
4823 perf_event_ctx_unlock(event, ctx);
4828 #ifdef CONFIG_COMPAT
4829 static long perf_compat_ioctl(struct file *file, unsigned int cmd,
4832 switch (_IOC_NR(cmd)) {
4833 case _IOC_NR(PERF_EVENT_IOC_SET_FILTER):
4834 case _IOC_NR(PERF_EVENT_IOC_ID):
4835 /* Fix up pointer size (usually 4 -> 8 in 32-on-64-bit case */
4836 if (_IOC_SIZE(cmd) == sizeof(compat_uptr_t)) {
4837 cmd &= ~IOCSIZE_MASK;
4838 cmd |= sizeof(void *) << IOCSIZE_SHIFT;
4842 return perf_ioctl(file, cmd, arg);
4845 # define perf_compat_ioctl NULL
4848 int perf_event_task_enable(void)
4850 struct perf_event_context *ctx;
4851 struct perf_event *event;
4853 mutex_lock(¤t->perf_event_mutex);
4854 list_for_each_entry(event, ¤t->perf_event_list, owner_entry) {
4855 ctx = perf_event_ctx_lock(event);
4856 perf_event_for_each_child(event, _perf_event_enable);
4857 perf_event_ctx_unlock(event, ctx);
4859 mutex_unlock(¤t->perf_event_mutex);
4864 int perf_event_task_disable(void)
4866 struct perf_event_context *ctx;
4867 struct perf_event *event;
4869 mutex_lock(¤t->perf_event_mutex);
4870 list_for_each_entry(event, ¤t->perf_event_list, owner_entry) {
4871 ctx = perf_event_ctx_lock(event);
4872 perf_event_for_each_child(event, _perf_event_disable);
4873 perf_event_ctx_unlock(event, ctx);
4875 mutex_unlock(¤t->perf_event_mutex);
4880 static int perf_event_index(struct perf_event *event)
4882 if (event->hw.state & PERF_HES_STOPPED)
4885 if (event->state != PERF_EVENT_STATE_ACTIVE)
4888 return event->pmu->event_idx(event);
4891 static void calc_timer_values(struct perf_event *event,
4898 *now = perf_clock();
4899 ctx_time = event->shadow_ctx_time + *now;
4900 *enabled = ctx_time - event->tstamp_enabled;
4901 *running = ctx_time - event->tstamp_running;
4904 static void perf_event_init_userpage(struct perf_event *event)
4906 struct perf_event_mmap_page *userpg;
4907 struct ring_buffer *rb;
4910 rb = rcu_dereference(event->rb);
4914 userpg = rb->user_page;
4916 /* Allow new userspace to detect that bit 0 is deprecated */
4917 userpg->cap_bit0_is_deprecated = 1;
4918 userpg->size = offsetof(struct perf_event_mmap_page, __reserved);
4919 userpg->data_offset = PAGE_SIZE;
4920 userpg->data_size = perf_data_size(rb);
4926 void __weak arch_perf_update_userpage(
4927 struct perf_event *event, struct perf_event_mmap_page *userpg, u64 now)
4932 * Callers need to ensure there can be no nesting of this function, otherwise
4933 * the seqlock logic goes bad. We can not serialize this because the arch
4934 * code calls this from NMI context.
4936 void perf_event_update_userpage(struct perf_event *event)
4938 struct perf_event_mmap_page *userpg;
4939 struct ring_buffer *rb;
4940 u64 enabled, running, now;
4943 rb = rcu_dereference(event->rb);
4948 * compute total_time_enabled, total_time_running
4949 * based on snapshot values taken when the event
4950 * was last scheduled in.
4952 * we cannot simply called update_context_time()
4953 * because of locking issue as we can be called in
4956 calc_timer_values(event, &now, &enabled, &running);
4958 userpg = rb->user_page;
4960 * Disable preemption so as to not let the corresponding user-space
4961 * spin too long if we get preempted.
4966 userpg->index = perf_event_index(event);
4967 userpg->offset = perf_event_count(event);
4969 userpg->offset -= local64_read(&event->hw.prev_count);
4971 userpg->time_enabled = enabled +
4972 atomic64_read(&event->child_total_time_enabled);
4974 userpg->time_running = running +
4975 atomic64_read(&event->child_total_time_running);
4977 arch_perf_update_userpage(event, userpg, now);
4986 static int perf_mmap_fault(struct vm_fault *vmf)
4988 struct perf_event *event = vmf->vma->vm_file->private_data;
4989 struct ring_buffer *rb;
4990 int ret = VM_FAULT_SIGBUS;
4992 if (vmf->flags & FAULT_FLAG_MKWRITE) {
4993 if (vmf->pgoff == 0)
4999 rb = rcu_dereference(event->rb);
5003 if (vmf->pgoff && (vmf->flags & FAULT_FLAG_WRITE))
5006 vmf->page = perf_mmap_to_page(rb, vmf->pgoff);
5010 get_page(vmf->page);
5011 vmf->page->mapping = vmf->vma->vm_file->f_mapping;
5012 vmf->page->index = vmf->pgoff;
5021 static void ring_buffer_attach(struct perf_event *event,
5022 struct ring_buffer *rb)
5024 struct ring_buffer *old_rb = NULL;
5025 unsigned long flags;
5029 * Should be impossible, we set this when removing
5030 * event->rb_entry and wait/clear when adding event->rb_entry.
5032 WARN_ON_ONCE(event->rcu_pending);
5035 spin_lock_irqsave(&old_rb->event_lock, flags);
5036 list_del_rcu(&event->rb_entry);
5037 spin_unlock_irqrestore(&old_rb->event_lock, flags);
5039 event->rcu_batches = get_state_synchronize_rcu();
5040 event->rcu_pending = 1;
5044 if (event->rcu_pending) {
5045 cond_synchronize_rcu(event->rcu_batches);
5046 event->rcu_pending = 0;
5049 spin_lock_irqsave(&rb->event_lock, flags);
5050 list_add_rcu(&event->rb_entry, &rb->event_list);
5051 spin_unlock_irqrestore(&rb->event_lock, flags);
5055 * Avoid racing with perf_mmap_close(AUX): stop the event
5056 * before swizzling the event::rb pointer; if it's getting
5057 * unmapped, its aux_mmap_count will be 0 and it won't
5058 * restart. See the comment in __perf_pmu_output_stop().
5060 * Data will inevitably be lost when set_output is done in
5061 * mid-air, but then again, whoever does it like this is
5062 * not in for the data anyway.
5065 perf_event_stop(event, 0);
5067 rcu_assign_pointer(event->rb, rb);
5070 ring_buffer_put(old_rb);
5072 * Since we detached before setting the new rb, so that we
5073 * could attach the new rb, we could have missed a wakeup.
5076 wake_up_all(&event->waitq);
5080 static void ring_buffer_wakeup(struct perf_event *event)
5082 struct ring_buffer *rb;
5085 rb = rcu_dereference(event->rb);
5087 list_for_each_entry_rcu(event, &rb->event_list, rb_entry)
5088 wake_up_all(&event->waitq);
5093 struct ring_buffer *ring_buffer_get(struct perf_event *event)
5095 struct ring_buffer *rb;
5098 rb = rcu_dereference(event->rb);
5100 if (!atomic_inc_not_zero(&rb->refcount))
5108 void ring_buffer_put(struct ring_buffer *rb)
5110 if (!atomic_dec_and_test(&rb->refcount))
5113 WARN_ON_ONCE(!list_empty(&rb->event_list));
5115 call_rcu(&rb->rcu_head, rb_free_rcu);
5118 static void perf_mmap_open(struct vm_area_struct *vma)
5120 struct perf_event *event = vma->vm_file->private_data;
5122 atomic_inc(&event->mmap_count);
5123 atomic_inc(&event->rb->mmap_count);
5126 atomic_inc(&event->rb->aux_mmap_count);
5128 if (event->pmu->event_mapped)
5129 event->pmu->event_mapped(event, vma->vm_mm);
5132 static void perf_pmu_output_stop(struct perf_event *event);
5135 * A buffer can be mmap()ed multiple times; either directly through the same
5136 * event, or through other events by use of perf_event_set_output().
5138 * In order to undo the VM accounting done by perf_mmap() we need to destroy
5139 * the buffer here, where we still have a VM context. This means we need
5140 * to detach all events redirecting to us.
5142 static void perf_mmap_close(struct vm_area_struct *vma)
5144 struct perf_event *event = vma->vm_file->private_data;
5146 struct ring_buffer *rb = ring_buffer_get(event);
5147 struct user_struct *mmap_user = rb->mmap_user;
5148 int mmap_locked = rb->mmap_locked;
5149 unsigned long size = perf_data_size(rb);
5151 if (event->pmu->event_unmapped)
5152 event->pmu->event_unmapped(event, vma->vm_mm);
5155 * rb->aux_mmap_count will always drop before rb->mmap_count and
5156 * event->mmap_count, so it is ok to use event->mmap_mutex to
5157 * serialize with perf_mmap here.
5159 if (rb_has_aux(rb) && vma->vm_pgoff == rb->aux_pgoff &&
5160 atomic_dec_and_mutex_lock(&rb->aux_mmap_count, &event->mmap_mutex)) {
5162 * Stop all AUX events that are writing to this buffer,
5163 * so that we can free its AUX pages and corresponding PMU
5164 * data. Note that after rb::aux_mmap_count dropped to zero,
5165 * they won't start any more (see perf_aux_output_begin()).
5167 perf_pmu_output_stop(event);
5169 /* now it's safe to free the pages */
5170 atomic_long_sub(rb->aux_nr_pages, &mmap_user->locked_vm);
5171 vma->vm_mm->pinned_vm -= rb->aux_mmap_locked;
5173 /* this has to be the last one */
5175 WARN_ON_ONCE(atomic_read(&rb->aux_refcount));
5177 mutex_unlock(&event->mmap_mutex);
5180 atomic_dec(&rb->mmap_count);
5182 if (!atomic_dec_and_mutex_lock(&event->mmap_count, &event->mmap_mutex))
5185 ring_buffer_attach(event, NULL);
5186 mutex_unlock(&event->mmap_mutex);
5188 /* If there's still other mmap()s of this buffer, we're done. */
5189 if (atomic_read(&rb->mmap_count))
5193 * No other mmap()s, detach from all other events that might redirect
5194 * into the now unreachable buffer. Somewhat complicated by the
5195 * fact that rb::event_lock otherwise nests inside mmap_mutex.
5199 list_for_each_entry_rcu(event, &rb->event_list, rb_entry) {
5200 if (!atomic_long_inc_not_zero(&event->refcount)) {
5202 * This event is en-route to free_event() which will
5203 * detach it and remove it from the list.
5209 mutex_lock(&event->mmap_mutex);
5211 * Check we didn't race with perf_event_set_output() which can
5212 * swizzle the rb from under us while we were waiting to
5213 * acquire mmap_mutex.
5215 * If we find a different rb; ignore this event, a next
5216 * iteration will no longer find it on the list. We have to
5217 * still restart the iteration to make sure we're not now
5218 * iterating the wrong list.
5220 if (event->rb == rb)
5221 ring_buffer_attach(event, NULL);
5223 mutex_unlock(&event->mmap_mutex);
5227 * Restart the iteration; either we're on the wrong list or
5228 * destroyed its integrity by doing a deletion.
5235 * It could be there's still a few 0-ref events on the list; they'll
5236 * get cleaned up by free_event() -- they'll also still have their
5237 * ref on the rb and will free it whenever they are done with it.
5239 * Aside from that, this buffer is 'fully' detached and unmapped,
5240 * undo the VM accounting.
5243 atomic_long_sub((size >> PAGE_SHIFT) + 1, &mmap_user->locked_vm);
5244 vma->vm_mm->pinned_vm -= mmap_locked;
5245 free_uid(mmap_user);
5248 ring_buffer_put(rb); /* could be last */
5251 static const struct vm_operations_struct perf_mmap_vmops = {
5252 .open = perf_mmap_open,
5253 .close = perf_mmap_close, /* non mergable */
5254 .fault = perf_mmap_fault,
5255 .page_mkwrite = perf_mmap_fault,
5258 static int perf_mmap(struct file *file, struct vm_area_struct *vma)
5260 struct perf_event *event = file->private_data;
5261 unsigned long user_locked, user_lock_limit;
5262 struct user_struct *user = current_user();
5263 unsigned long locked, lock_limit;
5264 struct ring_buffer *rb = NULL;
5265 unsigned long vma_size;
5266 unsigned long nr_pages;
5267 long user_extra = 0, extra = 0;
5268 int ret = 0, flags = 0;
5271 * Don't allow mmap() of inherited per-task counters. This would
5272 * create a performance issue due to all children writing to the
5275 if (event->cpu == -1 && event->attr.inherit)
5278 if (!(vma->vm_flags & VM_SHARED))
5281 vma_size = vma->vm_end - vma->vm_start;
5283 if (vma->vm_pgoff == 0) {
5284 nr_pages = (vma_size / PAGE_SIZE) - 1;
5287 * AUX area mapping: if rb->aux_nr_pages != 0, it's already
5288 * mapped, all subsequent mappings should have the same size
5289 * and offset. Must be above the normal perf buffer.
5291 u64 aux_offset, aux_size;
5296 nr_pages = vma_size / PAGE_SIZE;
5298 mutex_lock(&event->mmap_mutex);
5305 aux_offset = ACCESS_ONCE(rb->user_page->aux_offset);
5306 aux_size = ACCESS_ONCE(rb->user_page->aux_size);
5308 if (aux_offset < perf_data_size(rb) + PAGE_SIZE)
5311 if (aux_offset != vma->vm_pgoff << PAGE_SHIFT)
5314 /* already mapped with a different offset */
5315 if (rb_has_aux(rb) && rb->aux_pgoff != vma->vm_pgoff)
5318 if (aux_size != vma_size || aux_size != nr_pages * PAGE_SIZE)
5321 /* already mapped with a different size */
5322 if (rb_has_aux(rb) && rb->aux_nr_pages != nr_pages)
5325 if (!is_power_of_2(nr_pages))
5328 if (!atomic_inc_not_zero(&rb->mmap_count))
5331 if (rb_has_aux(rb)) {
5332 atomic_inc(&rb->aux_mmap_count);
5337 atomic_set(&rb->aux_mmap_count, 1);
5338 user_extra = nr_pages;
5344 * If we have rb pages ensure they're a power-of-two number, so we
5345 * can do bitmasks instead of modulo.
5347 if (nr_pages != 0 && !is_power_of_2(nr_pages))
5350 if (vma_size != PAGE_SIZE * (1 + nr_pages))
5353 WARN_ON_ONCE(event->ctx->parent_ctx);
5355 mutex_lock(&event->mmap_mutex);
5357 if (event->rb->nr_pages != nr_pages) {
5362 if (!atomic_inc_not_zero(&event->rb->mmap_count)) {
5364 * Raced against perf_mmap_close() through
5365 * perf_event_set_output(). Try again, hope for better
5368 mutex_unlock(&event->mmap_mutex);
5375 user_extra = nr_pages + 1;
5378 user_lock_limit = sysctl_perf_event_mlock >> (PAGE_SHIFT - 10);
5381 * Increase the limit linearly with more CPUs:
5383 user_lock_limit *= num_online_cpus();
5385 user_locked = atomic_long_read(&user->locked_vm) + user_extra;
5387 if (user_locked > user_lock_limit)
5388 extra = user_locked - user_lock_limit;
5390 lock_limit = rlimit(RLIMIT_MEMLOCK);
5391 lock_limit >>= PAGE_SHIFT;
5392 locked = vma->vm_mm->pinned_vm + extra;
5394 if ((locked > lock_limit) && perf_paranoid_tracepoint_raw() &&
5395 !capable(CAP_IPC_LOCK)) {
5400 WARN_ON(!rb && event->rb);
5402 if (vma->vm_flags & VM_WRITE)
5403 flags |= RING_BUFFER_WRITABLE;
5406 rb = rb_alloc(nr_pages,
5407 event->attr.watermark ? event->attr.wakeup_watermark : 0,
5415 atomic_set(&rb->mmap_count, 1);
5416 rb->mmap_user = get_current_user();
5417 rb->mmap_locked = extra;
5419 ring_buffer_attach(event, rb);
5421 perf_event_init_userpage(event);
5422 perf_event_update_userpage(event);
5424 ret = rb_alloc_aux(rb, event, vma->vm_pgoff, nr_pages,
5425 event->attr.aux_watermark, flags);
5427 rb->aux_mmap_locked = extra;
5432 atomic_long_add(user_extra, &user->locked_vm);
5433 vma->vm_mm->pinned_vm += extra;
5435 atomic_inc(&event->mmap_count);
5437 atomic_dec(&rb->mmap_count);
5440 mutex_unlock(&event->mmap_mutex);
5443 * Since pinned accounting is per vm we cannot allow fork() to copy our
5446 vma->vm_flags |= VM_DONTCOPY | VM_DONTEXPAND | VM_DONTDUMP;
5447 vma->vm_ops = &perf_mmap_vmops;
5449 if (event->pmu->event_mapped)
5450 event->pmu->event_mapped(event, vma->vm_mm);
5455 static int perf_fasync(int fd, struct file *filp, int on)
5457 struct inode *inode = file_inode(filp);
5458 struct perf_event *event = filp->private_data;
5462 retval = fasync_helper(fd, filp, on, &event->fasync);
5463 inode_unlock(inode);
5471 static const struct file_operations perf_fops = {
5472 .llseek = no_llseek,
5473 .release = perf_release,
5476 .unlocked_ioctl = perf_ioctl,
5477 .compat_ioctl = perf_compat_ioctl,
5479 .fasync = perf_fasync,
5485 * If there's data, ensure we set the poll() state and publish everything
5486 * to user-space before waking everybody up.
5489 static inline struct fasync_struct **perf_event_fasync(struct perf_event *event)
5491 /* only the parent has fasync state */
5493 event = event->parent;
5494 return &event->fasync;
5497 void perf_event_wakeup(struct perf_event *event)
5499 ring_buffer_wakeup(event);
5501 if (event->pending_kill) {
5502 kill_fasync(perf_event_fasync(event), SIGIO, event->pending_kill);
5503 event->pending_kill = 0;
5507 static void perf_pending_event(struct irq_work *entry)
5509 struct perf_event *event = container_of(entry,
5510 struct perf_event, pending);
5513 rctx = perf_swevent_get_recursion_context();
5515 * If we 'fail' here, that's OK, it means recursion is already disabled
5516 * and we won't recurse 'further'.
5519 if (event->pending_disable) {
5520 event->pending_disable = 0;
5521 perf_event_disable_local(event);
5524 if (event->pending_wakeup) {
5525 event->pending_wakeup = 0;
5526 perf_event_wakeup(event);
5530 perf_swevent_put_recursion_context(rctx);
5534 * We assume there is only KVM supporting the callbacks.
5535 * Later on, we might change it to a list if there is
5536 * another virtualization implementation supporting the callbacks.
5538 struct perf_guest_info_callbacks *perf_guest_cbs;
5540 int perf_register_guest_info_callbacks(struct perf_guest_info_callbacks *cbs)
5542 perf_guest_cbs = cbs;
5545 EXPORT_SYMBOL_GPL(perf_register_guest_info_callbacks);
5547 int perf_unregister_guest_info_callbacks(struct perf_guest_info_callbacks *cbs)
5549 perf_guest_cbs = NULL;
5552 EXPORT_SYMBOL_GPL(perf_unregister_guest_info_callbacks);
5555 perf_output_sample_regs(struct perf_output_handle *handle,
5556 struct pt_regs *regs, u64 mask)
5559 DECLARE_BITMAP(_mask, 64);
5561 bitmap_from_u64(_mask, mask);
5562 for_each_set_bit(bit, _mask, sizeof(mask) * BITS_PER_BYTE) {
5565 val = perf_reg_value(regs, bit);
5566 perf_output_put(handle, val);
5570 static void perf_sample_regs_user(struct perf_regs *regs_user,
5571 struct pt_regs *regs,
5572 struct pt_regs *regs_user_copy)
5574 if (user_mode(regs)) {
5575 regs_user->abi = perf_reg_abi(current);
5576 regs_user->regs = regs;
5577 } else if (current->mm) {
5578 perf_get_regs_user(regs_user, regs, regs_user_copy);
5580 regs_user->abi = PERF_SAMPLE_REGS_ABI_NONE;
5581 regs_user->regs = NULL;
5585 static void perf_sample_regs_intr(struct perf_regs *regs_intr,
5586 struct pt_regs *regs)
5588 regs_intr->regs = regs;
5589 regs_intr->abi = perf_reg_abi(current);
5594 * Get remaining task size from user stack pointer.
5596 * It'd be better to take stack vma map and limit this more
5597 * precisly, but there's no way to get it safely under interrupt,
5598 * so using TASK_SIZE as limit.
5600 static u64 perf_ustack_task_size(struct pt_regs *regs)
5602 unsigned long addr = perf_user_stack_pointer(regs);
5604 if (!addr || addr >= TASK_SIZE)
5607 return TASK_SIZE - addr;
5611 perf_sample_ustack_size(u16 stack_size, u16 header_size,
5612 struct pt_regs *regs)
5616 /* No regs, no stack pointer, no dump. */
5621 * Check if we fit in with the requested stack size into the:
5623 * If we don't, we limit the size to the TASK_SIZE.
5625 * - remaining sample size
5626 * If we don't, we customize the stack size to
5627 * fit in to the remaining sample size.
5630 task_size = min((u64) USHRT_MAX, perf_ustack_task_size(regs));
5631 stack_size = min(stack_size, (u16) task_size);
5633 /* Current header size plus static size and dynamic size. */
5634 header_size += 2 * sizeof(u64);
5636 /* Do we fit in with the current stack dump size? */
5637 if ((u16) (header_size + stack_size) < header_size) {
5639 * If we overflow the maximum size for the sample,
5640 * we customize the stack dump size to fit in.
5642 stack_size = USHRT_MAX - header_size - sizeof(u64);
5643 stack_size = round_up(stack_size, sizeof(u64));
5650 perf_output_sample_ustack(struct perf_output_handle *handle, u64 dump_size,
5651 struct pt_regs *regs)
5653 /* Case of a kernel thread, nothing to dump */
5656 perf_output_put(handle, size);
5665 * - the size requested by user or the best one we can fit
5666 * in to the sample max size
5668 * - user stack dump data
5670 * - the actual dumped size
5674 perf_output_put(handle, dump_size);
5677 sp = perf_user_stack_pointer(regs);
5678 rem = __output_copy_user(handle, (void *) sp, dump_size);
5679 dyn_size = dump_size - rem;
5681 perf_output_skip(handle, rem);
5684 perf_output_put(handle, dyn_size);
5688 static void __perf_event_header__init_id(struct perf_event_header *header,
5689 struct perf_sample_data *data,
5690 struct perf_event *event)
5692 u64 sample_type = event->attr.sample_type;
5694 data->type = sample_type;
5695 header->size += event->id_header_size;
5697 if (sample_type & PERF_SAMPLE_TID) {
5698 /* namespace issues */
5699 data->tid_entry.pid = perf_event_pid(event, current);
5700 data->tid_entry.tid = perf_event_tid(event, current);
5703 if (sample_type & PERF_SAMPLE_TIME)
5704 data->time = perf_event_clock(event);
5706 if (sample_type & (PERF_SAMPLE_ID | PERF_SAMPLE_IDENTIFIER))
5707 data->id = primary_event_id(event);
5709 if (sample_type & PERF_SAMPLE_STREAM_ID)
5710 data->stream_id = event->id;
5712 if (sample_type & PERF_SAMPLE_CPU) {
5713 data->cpu_entry.cpu = raw_smp_processor_id();
5714 data->cpu_entry.reserved = 0;
5718 void perf_event_header__init_id(struct perf_event_header *header,
5719 struct perf_sample_data *data,
5720 struct perf_event *event)
5722 if (event->attr.sample_id_all)
5723 __perf_event_header__init_id(header, data, event);
5726 static void __perf_event__output_id_sample(struct perf_output_handle *handle,
5727 struct perf_sample_data *data)
5729 u64 sample_type = data->type;
5731 if (sample_type & PERF_SAMPLE_TID)
5732 perf_output_put(handle, data->tid_entry);
5734 if (sample_type & PERF_SAMPLE_TIME)
5735 perf_output_put(handle, data->time);
5737 if (sample_type & PERF_SAMPLE_ID)
5738 perf_output_put(handle, data->id);
5740 if (sample_type & PERF_SAMPLE_STREAM_ID)
5741 perf_output_put(handle, data->stream_id);
5743 if (sample_type & PERF_SAMPLE_CPU)
5744 perf_output_put(handle, data->cpu_entry);
5746 if (sample_type & PERF_SAMPLE_IDENTIFIER)
5747 perf_output_put(handle, data->id);
5750 void perf_event__output_id_sample(struct perf_event *event,
5751 struct perf_output_handle *handle,
5752 struct perf_sample_data *sample)
5754 if (event->attr.sample_id_all)
5755 __perf_event__output_id_sample(handle, sample);
5758 static void perf_output_read_one(struct perf_output_handle *handle,
5759 struct perf_event *event,
5760 u64 enabled, u64 running)
5762 u64 read_format = event->attr.read_format;
5766 values[n++] = perf_event_count(event);
5767 if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED) {
5768 values[n++] = enabled +
5769 atomic64_read(&event->child_total_time_enabled);
5771 if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING) {
5772 values[n++] = running +
5773 atomic64_read(&event->child_total_time_running);
5775 if (read_format & PERF_FORMAT_ID)
5776 values[n++] = primary_event_id(event);
5778 __output_copy(handle, values, n * sizeof(u64));
5781 static void perf_output_read_group(struct perf_output_handle *handle,
5782 struct perf_event *event,
5783 u64 enabled, u64 running)
5785 struct perf_event *leader = event->group_leader, *sub;
5786 u64 read_format = event->attr.read_format;
5790 values[n++] = 1 + leader->nr_siblings;
5792 if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED)
5793 values[n++] = enabled;
5795 if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING)
5796 values[n++] = running;
5798 if (leader != event)
5799 leader->pmu->read(leader);
5801 values[n++] = perf_event_count(leader);
5802 if (read_format & PERF_FORMAT_ID)
5803 values[n++] = primary_event_id(leader);
5805 __output_copy(handle, values, n * sizeof(u64));
5807 list_for_each_entry(sub, &leader->sibling_list, group_entry) {
5810 if ((sub != event) &&
5811 (sub->state == PERF_EVENT_STATE_ACTIVE))
5812 sub->pmu->read(sub);
5814 values[n++] = perf_event_count(sub);
5815 if (read_format & PERF_FORMAT_ID)
5816 values[n++] = primary_event_id(sub);
5818 __output_copy(handle, values, n * sizeof(u64));
5822 #define PERF_FORMAT_TOTAL_TIMES (PERF_FORMAT_TOTAL_TIME_ENABLED|\
5823 PERF_FORMAT_TOTAL_TIME_RUNNING)
5826 * XXX PERF_SAMPLE_READ vs inherited events seems difficult.
5828 * The problem is that its both hard and excessively expensive to iterate the
5829 * child list, not to mention that its impossible to IPI the children running
5830 * on another CPU, from interrupt/NMI context.
5832 static void perf_output_read(struct perf_output_handle *handle,
5833 struct perf_event *event)
5835 u64 enabled = 0, running = 0, now;
5836 u64 read_format = event->attr.read_format;
5839 * compute total_time_enabled, total_time_running
5840 * based on snapshot values taken when the event
5841 * was last scheduled in.
5843 * we cannot simply called update_context_time()
5844 * because of locking issue as we are called in
5847 if (read_format & PERF_FORMAT_TOTAL_TIMES)
5848 calc_timer_values(event, &now, &enabled, &running);
5850 if (event->attr.read_format & PERF_FORMAT_GROUP)
5851 perf_output_read_group(handle, event, enabled, running);
5853 perf_output_read_one(handle, event, enabled, running);
5856 void perf_output_sample(struct perf_output_handle *handle,
5857 struct perf_event_header *header,
5858 struct perf_sample_data *data,
5859 struct perf_event *event)
5861 u64 sample_type = data->type;
5863 perf_output_put(handle, *header);
5865 if (sample_type & PERF_SAMPLE_IDENTIFIER)
5866 perf_output_put(handle, data->id);
5868 if (sample_type & PERF_SAMPLE_IP)
5869 perf_output_put(handle, data->ip);
5871 if (sample_type & PERF_SAMPLE_TID)
5872 perf_output_put(handle, data->tid_entry);
5874 if (sample_type & PERF_SAMPLE_TIME)
5875 perf_output_put(handle, data->time);
5877 if (sample_type & PERF_SAMPLE_ADDR)
5878 perf_output_put(handle, data->addr);
5880 if (sample_type & PERF_SAMPLE_ID)
5881 perf_output_put(handle, data->id);
5883 if (sample_type & PERF_SAMPLE_STREAM_ID)
5884 perf_output_put(handle, data->stream_id);
5886 if (sample_type & PERF_SAMPLE_CPU)
5887 perf_output_put(handle, data->cpu_entry);
5889 if (sample_type & PERF_SAMPLE_PERIOD)
5890 perf_output_put(handle, data->period);
5892 if (sample_type & PERF_SAMPLE_READ)
5893 perf_output_read(handle, event);
5895 if (sample_type & PERF_SAMPLE_CALLCHAIN) {
5896 if (data->callchain) {
5899 if (data->callchain)
5900 size += data->callchain->nr;
5902 size *= sizeof(u64);
5904 __output_copy(handle, data->callchain, size);
5907 perf_output_put(handle, nr);
5911 if (sample_type & PERF_SAMPLE_RAW) {
5912 struct perf_raw_record *raw = data->raw;
5915 struct perf_raw_frag *frag = &raw->frag;
5917 perf_output_put(handle, raw->size);
5920 __output_custom(handle, frag->copy,
5921 frag->data, frag->size);
5923 __output_copy(handle, frag->data,
5926 if (perf_raw_frag_last(frag))
5931 __output_skip(handle, NULL, frag->pad);
5937 .size = sizeof(u32),
5940 perf_output_put(handle, raw);
5944 if (sample_type & PERF_SAMPLE_BRANCH_STACK) {
5945 if (data->br_stack) {
5948 size = data->br_stack->nr
5949 * sizeof(struct perf_branch_entry);
5951 perf_output_put(handle, data->br_stack->nr);
5952 perf_output_copy(handle, data->br_stack->entries, size);
5955 * we always store at least the value of nr
5958 perf_output_put(handle, nr);
5962 if (sample_type & PERF_SAMPLE_REGS_USER) {
5963 u64 abi = data->regs_user.abi;
5966 * If there are no regs to dump, notice it through
5967 * first u64 being zero (PERF_SAMPLE_REGS_ABI_NONE).
5969 perf_output_put(handle, abi);
5972 u64 mask = event->attr.sample_regs_user;
5973 perf_output_sample_regs(handle,
5974 data->regs_user.regs,
5979 if (sample_type & PERF_SAMPLE_STACK_USER) {
5980 perf_output_sample_ustack(handle,
5981 data->stack_user_size,
5982 data->regs_user.regs);
5985 if (sample_type & PERF_SAMPLE_WEIGHT)
5986 perf_output_put(handle, data->weight);
5988 if (sample_type & PERF_SAMPLE_DATA_SRC)
5989 perf_output_put(handle, data->data_src.val);
5991 if (sample_type & PERF_SAMPLE_TRANSACTION)
5992 perf_output_put(handle, data->txn);
5994 if (sample_type & PERF_SAMPLE_REGS_INTR) {
5995 u64 abi = data->regs_intr.abi;
5997 * If there are no regs to dump, notice it through
5998 * first u64 being zero (PERF_SAMPLE_REGS_ABI_NONE).
6000 perf_output_put(handle, abi);
6003 u64 mask = event->attr.sample_regs_intr;
6005 perf_output_sample_regs(handle,
6006 data->regs_intr.regs,
6011 if (sample_type & PERF_SAMPLE_PHYS_ADDR)
6012 perf_output_put(handle, data->phys_addr);
6014 if (!event->attr.watermark) {
6015 int wakeup_events = event->attr.wakeup_events;
6017 if (wakeup_events) {
6018 struct ring_buffer *rb = handle->rb;
6019 int events = local_inc_return(&rb->events);
6021 if (events >= wakeup_events) {
6022 local_sub(wakeup_events, &rb->events);
6023 local_inc(&rb->wakeup);
6029 static u64 perf_virt_to_phys(u64 virt)
6032 struct page *p = NULL;
6037 if (virt >= TASK_SIZE) {
6038 /* If it's vmalloc()d memory, leave phys_addr as 0 */
6039 if (virt_addr_valid((void *)(uintptr_t)virt) &&
6040 !(virt >= VMALLOC_START && virt < VMALLOC_END))
6041 phys_addr = (u64)virt_to_phys((void *)(uintptr_t)virt);
6044 * Walking the pages tables for user address.
6045 * Interrupts are disabled, so it prevents any tear down
6046 * of the page tables.
6047 * Try IRQ-safe __get_user_pages_fast first.
6048 * If failed, leave phys_addr as 0.
6050 if ((current->mm != NULL) &&
6051 (__get_user_pages_fast(virt, 1, 0, &p) == 1))
6052 phys_addr = page_to_phys(p) + virt % PAGE_SIZE;
6061 void perf_prepare_sample(struct perf_event_header *header,
6062 struct perf_sample_data *data,
6063 struct perf_event *event,
6064 struct pt_regs *regs)
6066 u64 sample_type = event->attr.sample_type;
6068 header->type = PERF_RECORD_SAMPLE;
6069 header->size = sizeof(*header) + event->header_size;
6072 header->misc |= perf_misc_flags(regs);
6074 __perf_event_header__init_id(header, data, event);
6076 if (sample_type & PERF_SAMPLE_IP)
6077 data->ip = perf_instruction_pointer(regs);
6079 if (sample_type & PERF_SAMPLE_CALLCHAIN) {
6082 data->callchain = perf_callchain(event, regs);
6084 if (data->callchain)
6085 size += data->callchain->nr;
6087 header->size += size * sizeof(u64);
6090 if (sample_type & PERF_SAMPLE_RAW) {
6091 struct perf_raw_record *raw = data->raw;
6095 struct perf_raw_frag *frag = &raw->frag;
6100 if (perf_raw_frag_last(frag))
6105 size = round_up(sum + sizeof(u32), sizeof(u64));
6106 raw->size = size - sizeof(u32);
6107 frag->pad = raw->size - sum;
6112 header->size += size;
6115 if (sample_type & PERF_SAMPLE_BRANCH_STACK) {
6116 int size = sizeof(u64); /* nr */
6117 if (data->br_stack) {
6118 size += data->br_stack->nr
6119 * sizeof(struct perf_branch_entry);
6121 header->size += size;
6124 if (sample_type & (PERF_SAMPLE_REGS_USER | PERF_SAMPLE_STACK_USER))
6125 perf_sample_regs_user(&data->regs_user, regs,
6126 &data->regs_user_copy);
6128 if (sample_type & PERF_SAMPLE_REGS_USER) {
6129 /* regs dump ABI info */
6130 int size = sizeof(u64);
6132 if (data->regs_user.regs) {
6133 u64 mask = event->attr.sample_regs_user;
6134 size += hweight64(mask) * sizeof(u64);
6137 header->size += size;
6140 if (sample_type & PERF_SAMPLE_STACK_USER) {
6142 * Either we need PERF_SAMPLE_STACK_USER bit to be allways
6143 * processed as the last one or have additional check added
6144 * in case new sample type is added, because we could eat
6145 * up the rest of the sample size.
6147 u16 stack_size = event->attr.sample_stack_user;
6148 u16 size = sizeof(u64);
6150 stack_size = perf_sample_ustack_size(stack_size, header->size,
6151 data->regs_user.regs);
6154 * If there is something to dump, add space for the dump
6155 * itself and for the field that tells the dynamic size,
6156 * which is how many have been actually dumped.
6159 size += sizeof(u64) + stack_size;
6161 data->stack_user_size = stack_size;
6162 header->size += size;
6165 if (sample_type & PERF_SAMPLE_REGS_INTR) {
6166 /* regs dump ABI info */
6167 int size = sizeof(u64);
6169 perf_sample_regs_intr(&data->regs_intr, regs);
6171 if (data->regs_intr.regs) {
6172 u64 mask = event->attr.sample_regs_intr;
6174 size += hweight64(mask) * sizeof(u64);
6177 header->size += size;
6180 if (sample_type & PERF_SAMPLE_PHYS_ADDR)
6181 data->phys_addr = perf_virt_to_phys(data->addr);
6184 static void __always_inline
6185 __perf_event_output(struct perf_event *event,
6186 struct perf_sample_data *data,
6187 struct pt_regs *regs,
6188 int (*output_begin)(struct perf_output_handle *,
6189 struct perf_event *,
6192 struct perf_output_handle handle;
6193 struct perf_event_header header;
6195 /* protect the callchain buffers */
6198 perf_prepare_sample(&header, data, event, regs);
6200 if (output_begin(&handle, event, header.size))
6203 perf_output_sample(&handle, &header, data, event);
6205 perf_output_end(&handle);
6212 perf_event_output_forward(struct perf_event *event,
6213 struct perf_sample_data *data,
6214 struct pt_regs *regs)
6216 __perf_event_output(event, data, regs, perf_output_begin_forward);
6220 perf_event_output_backward(struct perf_event *event,
6221 struct perf_sample_data *data,
6222 struct pt_regs *regs)
6224 __perf_event_output(event, data, regs, perf_output_begin_backward);
6228 perf_event_output(struct perf_event *event,
6229 struct perf_sample_data *data,
6230 struct pt_regs *regs)
6232 __perf_event_output(event, data, regs, perf_output_begin);
6239 struct perf_read_event {
6240 struct perf_event_header header;
6247 perf_event_read_event(struct perf_event *event,
6248 struct task_struct *task)
6250 struct perf_output_handle handle;
6251 struct perf_sample_data sample;
6252 struct perf_read_event read_event = {
6254 .type = PERF_RECORD_READ,
6256 .size = sizeof(read_event) + event->read_size,
6258 .pid = perf_event_pid(event, task),
6259 .tid = perf_event_tid(event, task),
6263 perf_event_header__init_id(&read_event.header, &sample, event);
6264 ret = perf_output_begin(&handle, event, read_event.header.size);
6268 perf_output_put(&handle, read_event);
6269 perf_output_read(&handle, event);
6270 perf_event__output_id_sample(event, &handle, &sample);
6272 perf_output_end(&handle);
6275 typedef void (perf_iterate_f)(struct perf_event *event, void *data);
6278 perf_iterate_ctx(struct perf_event_context *ctx,
6279 perf_iterate_f output,
6280 void *data, bool all)
6282 struct perf_event *event;
6284 list_for_each_entry_rcu(event, &ctx->event_list, event_entry) {
6286 if (event->state < PERF_EVENT_STATE_INACTIVE)
6288 if (!event_filter_match(event))
6292 output(event, data);
6296 static void perf_iterate_sb_cpu(perf_iterate_f output, void *data)
6298 struct pmu_event_list *pel = this_cpu_ptr(&pmu_sb_events);
6299 struct perf_event *event;
6301 list_for_each_entry_rcu(event, &pel->list, sb_list) {
6303 * Skip events that are not fully formed yet; ensure that
6304 * if we observe event->ctx, both event and ctx will be
6305 * complete enough. See perf_install_in_context().
6307 if (!smp_load_acquire(&event->ctx))
6310 if (event->state < PERF_EVENT_STATE_INACTIVE)
6312 if (!event_filter_match(event))
6314 output(event, data);
6319 * Iterate all events that need to receive side-band events.
6321 * For new callers; ensure that account_pmu_sb_event() includes
6322 * your event, otherwise it might not get delivered.
6325 perf_iterate_sb(perf_iterate_f output, void *data,
6326 struct perf_event_context *task_ctx)
6328 struct perf_event_context *ctx;
6335 * If we have task_ctx != NULL we only notify the task context itself.
6336 * The task_ctx is set only for EXIT events before releasing task
6340 perf_iterate_ctx(task_ctx, output, data, false);
6344 perf_iterate_sb_cpu(output, data);
6346 for_each_task_context_nr(ctxn) {
6347 ctx = rcu_dereference(current->perf_event_ctxp[ctxn]);
6349 perf_iterate_ctx(ctx, output, data, false);
6357 * Clear all file-based filters at exec, they'll have to be
6358 * re-instated when/if these objects are mmapped again.
6360 static void perf_event_addr_filters_exec(struct perf_event *event, void *data)
6362 struct perf_addr_filters_head *ifh = perf_event_addr_filters(event);
6363 struct perf_addr_filter *filter;
6364 unsigned int restart = 0, count = 0;
6365 unsigned long flags;
6367 if (!has_addr_filter(event))
6370 raw_spin_lock_irqsave(&ifh->lock, flags);
6371 list_for_each_entry(filter, &ifh->list, entry) {
6372 if (filter->inode) {
6373 event->addr_filters_offs[count] = 0;
6381 event->addr_filters_gen++;
6382 raw_spin_unlock_irqrestore(&ifh->lock, flags);
6385 perf_event_stop(event, 1);
6388 void perf_event_exec(void)
6390 struct perf_event_context *ctx;
6394 for_each_task_context_nr(ctxn) {
6395 ctx = current->perf_event_ctxp[ctxn];
6399 perf_event_enable_on_exec(ctxn);
6401 perf_iterate_ctx(ctx, perf_event_addr_filters_exec, NULL,
6407 struct remote_output {
6408 struct ring_buffer *rb;
6412 static void __perf_event_output_stop(struct perf_event *event, void *data)
6414 struct perf_event *parent = event->parent;
6415 struct remote_output *ro = data;
6416 struct ring_buffer *rb = ro->rb;
6417 struct stop_event_data sd = {
6421 if (!has_aux(event))
6428 * In case of inheritance, it will be the parent that links to the
6429 * ring-buffer, but it will be the child that's actually using it.
6431 * We are using event::rb to determine if the event should be stopped,
6432 * however this may race with ring_buffer_attach() (through set_output),
6433 * which will make us skip the event that actually needs to be stopped.
6434 * So ring_buffer_attach() has to stop an aux event before re-assigning
6437 if (rcu_dereference(parent->rb) == rb)
6438 ro->err = __perf_event_stop(&sd);
6441 static int __perf_pmu_output_stop(void *info)
6443 struct perf_event *event = info;
6444 struct pmu *pmu = event->pmu;
6445 struct perf_cpu_context *cpuctx = this_cpu_ptr(pmu->pmu_cpu_context);
6446 struct remote_output ro = {
6451 perf_iterate_ctx(&cpuctx->ctx, __perf_event_output_stop, &ro, false);
6452 if (cpuctx->task_ctx)
6453 perf_iterate_ctx(cpuctx->task_ctx, __perf_event_output_stop,
6460 static void perf_pmu_output_stop(struct perf_event *event)
6462 struct perf_event *iter;
6467 list_for_each_entry_rcu(iter, &event->rb->event_list, rb_entry) {
6469 * For per-CPU events, we need to make sure that neither they
6470 * nor their children are running; for cpu==-1 events it's
6471 * sufficient to stop the event itself if it's active, since
6472 * it can't have children.
6476 cpu = READ_ONCE(iter->oncpu);
6481 err = cpu_function_call(cpu, __perf_pmu_output_stop, event);
6482 if (err == -EAGAIN) {
6491 * task tracking -- fork/exit
6493 * enabled by: attr.comm | attr.mmap | attr.mmap2 | attr.mmap_data | attr.task
6496 struct perf_task_event {
6497 struct task_struct *task;
6498 struct perf_event_context *task_ctx;
6501 struct perf_event_header header;
6511 static int perf_event_task_match(struct perf_event *event)
6513 return event->attr.comm || event->attr.mmap ||
6514 event->attr.mmap2 || event->attr.mmap_data ||
6518 static void perf_event_task_output(struct perf_event *event,
6521 struct perf_task_event *task_event = data;
6522 struct perf_output_handle handle;
6523 struct perf_sample_data sample;
6524 struct task_struct *task = task_event->task;
6525 int ret, size = task_event->event_id.header.size;
6527 if (!perf_event_task_match(event))
6530 perf_event_header__init_id(&task_event->event_id.header, &sample, event);
6532 ret = perf_output_begin(&handle, event,
6533 task_event->event_id.header.size);
6537 task_event->event_id.pid = perf_event_pid(event, task);
6538 task_event->event_id.ppid = perf_event_pid(event, current);
6540 task_event->event_id.tid = perf_event_tid(event, task);
6541 task_event->event_id.ptid = perf_event_tid(event, current);
6543 task_event->event_id.time = perf_event_clock(event);
6545 perf_output_put(&handle, task_event->event_id);
6547 perf_event__output_id_sample(event, &handle, &sample);
6549 perf_output_end(&handle);
6551 task_event->event_id.header.size = size;
6554 static void perf_event_task(struct task_struct *task,
6555 struct perf_event_context *task_ctx,
6558 struct perf_task_event task_event;
6560 if (!atomic_read(&nr_comm_events) &&
6561 !atomic_read(&nr_mmap_events) &&
6562 !atomic_read(&nr_task_events))
6565 task_event = (struct perf_task_event){
6567 .task_ctx = task_ctx,
6570 .type = new ? PERF_RECORD_FORK : PERF_RECORD_EXIT,
6572 .size = sizeof(task_event.event_id),
6582 perf_iterate_sb(perf_event_task_output,
6587 void perf_event_fork(struct task_struct *task)
6589 perf_event_task(task, NULL, 1);
6590 perf_event_namespaces(task);
6597 struct perf_comm_event {
6598 struct task_struct *task;
6603 struct perf_event_header header;
6610 static int perf_event_comm_match(struct perf_event *event)
6612 return event->attr.comm;
6615 static void perf_event_comm_output(struct perf_event *event,
6618 struct perf_comm_event *comm_event = data;
6619 struct perf_output_handle handle;
6620 struct perf_sample_data sample;
6621 int size = comm_event->event_id.header.size;
6624 if (!perf_event_comm_match(event))
6627 perf_event_header__init_id(&comm_event->event_id.header, &sample, event);
6628 ret = perf_output_begin(&handle, event,
6629 comm_event->event_id.header.size);
6634 comm_event->event_id.pid = perf_event_pid(event, comm_event->task);
6635 comm_event->event_id.tid = perf_event_tid(event, comm_event->task);
6637 perf_output_put(&handle, comm_event->event_id);
6638 __output_copy(&handle, comm_event->comm,
6639 comm_event->comm_size);
6641 perf_event__output_id_sample(event, &handle, &sample);
6643 perf_output_end(&handle);
6645 comm_event->event_id.header.size = size;
6648 static void perf_event_comm_event(struct perf_comm_event *comm_event)
6650 char comm[TASK_COMM_LEN];
6653 memset(comm, 0, sizeof(comm));
6654 strlcpy(comm, comm_event->task->comm, sizeof(comm));
6655 size = ALIGN(strlen(comm)+1, sizeof(u64));
6657 comm_event->comm = comm;
6658 comm_event->comm_size = size;
6660 comm_event->event_id.header.size = sizeof(comm_event->event_id) + size;
6662 perf_iterate_sb(perf_event_comm_output,
6667 void perf_event_comm(struct task_struct *task, bool exec)
6669 struct perf_comm_event comm_event;
6671 if (!atomic_read(&nr_comm_events))
6674 comm_event = (struct perf_comm_event){
6680 .type = PERF_RECORD_COMM,
6681 .misc = exec ? PERF_RECORD_MISC_COMM_EXEC : 0,
6689 perf_event_comm_event(&comm_event);
6693 * namespaces tracking
6696 struct perf_namespaces_event {
6697 struct task_struct *task;
6700 struct perf_event_header header;
6705 struct perf_ns_link_info link_info[NR_NAMESPACES];
6709 static int perf_event_namespaces_match(struct perf_event *event)
6711 return event->attr.namespaces;
6714 static void perf_event_namespaces_output(struct perf_event *event,
6717 struct perf_namespaces_event *namespaces_event = data;
6718 struct perf_output_handle handle;
6719 struct perf_sample_data sample;
6722 if (!perf_event_namespaces_match(event))
6725 perf_event_header__init_id(&namespaces_event->event_id.header,
6727 ret = perf_output_begin(&handle, event,
6728 namespaces_event->event_id.header.size);
6732 namespaces_event->event_id.pid = perf_event_pid(event,
6733 namespaces_event->task);
6734 namespaces_event->event_id.tid = perf_event_tid(event,
6735 namespaces_event->task);
6737 perf_output_put(&handle, namespaces_event->event_id);
6739 perf_event__output_id_sample(event, &handle, &sample);
6741 perf_output_end(&handle);
6744 static void perf_fill_ns_link_info(struct perf_ns_link_info *ns_link_info,
6745 struct task_struct *task,
6746 const struct proc_ns_operations *ns_ops)
6748 struct path ns_path;
6749 struct inode *ns_inode;
6752 error = ns_get_path(&ns_path, task, ns_ops);
6754 ns_inode = ns_path.dentry->d_inode;
6755 ns_link_info->dev = new_encode_dev(ns_inode->i_sb->s_dev);
6756 ns_link_info->ino = ns_inode->i_ino;
6760 void perf_event_namespaces(struct task_struct *task)
6762 struct perf_namespaces_event namespaces_event;
6763 struct perf_ns_link_info *ns_link_info;
6765 if (!atomic_read(&nr_namespaces_events))
6768 namespaces_event = (struct perf_namespaces_event){
6772 .type = PERF_RECORD_NAMESPACES,
6774 .size = sizeof(namespaces_event.event_id),
6778 .nr_namespaces = NR_NAMESPACES,
6779 /* .link_info[NR_NAMESPACES] */
6783 ns_link_info = namespaces_event.event_id.link_info;
6785 perf_fill_ns_link_info(&ns_link_info[MNT_NS_INDEX],
6786 task, &mntns_operations);
6788 #ifdef CONFIG_USER_NS
6789 perf_fill_ns_link_info(&ns_link_info[USER_NS_INDEX],
6790 task, &userns_operations);
6792 #ifdef CONFIG_NET_NS
6793 perf_fill_ns_link_info(&ns_link_info[NET_NS_INDEX],
6794 task, &netns_operations);
6796 #ifdef CONFIG_UTS_NS
6797 perf_fill_ns_link_info(&ns_link_info[UTS_NS_INDEX],
6798 task, &utsns_operations);
6800 #ifdef CONFIG_IPC_NS
6801 perf_fill_ns_link_info(&ns_link_info[IPC_NS_INDEX],
6802 task, &ipcns_operations);
6804 #ifdef CONFIG_PID_NS
6805 perf_fill_ns_link_info(&ns_link_info[PID_NS_INDEX],
6806 task, &pidns_operations);
6808 #ifdef CONFIG_CGROUPS
6809 perf_fill_ns_link_info(&ns_link_info[CGROUP_NS_INDEX],
6810 task, &cgroupns_operations);
6813 perf_iterate_sb(perf_event_namespaces_output,
6822 struct perf_mmap_event {
6823 struct vm_area_struct *vma;
6825 const char *file_name;
6833 struct perf_event_header header;
6843 static int perf_event_mmap_match(struct perf_event *event,
6846 struct perf_mmap_event *mmap_event = data;
6847 struct vm_area_struct *vma = mmap_event->vma;
6848 int executable = vma->vm_flags & VM_EXEC;
6850 return (!executable && event->attr.mmap_data) ||
6851 (executable && (event->attr.mmap || event->attr.mmap2));
6854 static void perf_event_mmap_output(struct perf_event *event,
6857 struct perf_mmap_event *mmap_event = data;
6858 struct perf_output_handle handle;
6859 struct perf_sample_data sample;
6860 int size = mmap_event->event_id.header.size;
6863 if (!perf_event_mmap_match(event, data))
6866 if (event->attr.mmap2) {
6867 mmap_event->event_id.header.type = PERF_RECORD_MMAP2;
6868 mmap_event->event_id.header.size += sizeof(mmap_event->maj);
6869 mmap_event->event_id.header.size += sizeof(mmap_event->min);
6870 mmap_event->event_id.header.size += sizeof(mmap_event->ino);
6871 mmap_event->event_id.header.size += sizeof(mmap_event->ino_generation);
6872 mmap_event->event_id.header.size += sizeof(mmap_event->prot);
6873 mmap_event->event_id.header.size += sizeof(mmap_event->flags);
6876 perf_event_header__init_id(&mmap_event->event_id.header, &sample, event);
6877 ret = perf_output_begin(&handle, event,
6878 mmap_event->event_id.header.size);
6882 mmap_event->event_id.pid = perf_event_pid(event, current);
6883 mmap_event->event_id.tid = perf_event_tid(event, current);
6885 perf_output_put(&handle, mmap_event->event_id);
6887 if (event->attr.mmap2) {
6888 perf_output_put(&handle, mmap_event->maj);
6889 perf_output_put(&handle, mmap_event->min);
6890 perf_output_put(&handle, mmap_event->ino);
6891 perf_output_put(&handle, mmap_event->ino_generation);
6892 perf_output_put(&handle, mmap_event->prot);
6893 perf_output_put(&handle, mmap_event->flags);
6896 __output_copy(&handle, mmap_event->file_name,
6897 mmap_event->file_size);
6899 perf_event__output_id_sample(event, &handle, &sample);
6901 perf_output_end(&handle);
6903 mmap_event->event_id.header.size = size;
6906 static void perf_event_mmap_event(struct perf_mmap_event *mmap_event)
6908 struct vm_area_struct *vma = mmap_event->vma;
6909 struct file *file = vma->vm_file;
6910 int maj = 0, min = 0;
6911 u64 ino = 0, gen = 0;
6912 u32 prot = 0, flags = 0;
6918 if (vma->vm_flags & VM_READ)
6920 if (vma->vm_flags & VM_WRITE)
6922 if (vma->vm_flags & VM_EXEC)
6925 if (vma->vm_flags & VM_MAYSHARE)
6928 flags = MAP_PRIVATE;
6930 if (vma->vm_flags & VM_DENYWRITE)
6931 flags |= MAP_DENYWRITE;
6932 if (vma->vm_flags & VM_MAYEXEC)
6933 flags |= MAP_EXECUTABLE;
6934 if (vma->vm_flags & VM_LOCKED)
6935 flags |= MAP_LOCKED;
6936 if (vma->vm_flags & VM_HUGETLB)
6937 flags |= MAP_HUGETLB;
6940 struct inode *inode;
6943 buf = kmalloc(PATH_MAX, GFP_KERNEL);
6949 * d_path() works from the end of the rb backwards, so we
6950 * need to add enough zero bytes after the string to handle
6951 * the 64bit alignment we do later.
6953 name = file_path(file, buf, PATH_MAX - sizeof(u64));
6958 inode = file_inode(vma->vm_file);
6959 dev = inode->i_sb->s_dev;
6961 gen = inode->i_generation;
6967 if (vma->vm_ops && vma->vm_ops->name) {
6968 name = (char *) vma->vm_ops->name(vma);
6973 name = (char *)arch_vma_name(vma);
6977 if (vma->vm_start <= vma->vm_mm->start_brk &&
6978 vma->vm_end >= vma->vm_mm->brk) {
6982 if (vma->vm_start <= vma->vm_mm->start_stack &&
6983 vma->vm_end >= vma->vm_mm->start_stack) {
6993 strlcpy(tmp, name, sizeof(tmp));
6997 * Since our buffer works in 8 byte units we need to align our string
6998 * size to a multiple of 8. However, we must guarantee the tail end is
6999 * zero'd out to avoid leaking random bits to userspace.
7001 size = strlen(name)+1;
7002 while (!IS_ALIGNED(size, sizeof(u64)))
7003 name[size++] = '\0';
7005 mmap_event->file_name = name;
7006 mmap_event->file_size = size;
7007 mmap_event->maj = maj;
7008 mmap_event->min = min;
7009 mmap_event->ino = ino;
7010 mmap_event->ino_generation = gen;
7011 mmap_event->prot = prot;
7012 mmap_event->flags = flags;
7014 if (!(vma->vm_flags & VM_EXEC))
7015 mmap_event->event_id.header.misc |= PERF_RECORD_MISC_MMAP_DATA;
7017 mmap_event->event_id.header.size = sizeof(mmap_event->event_id) + size;
7019 perf_iterate_sb(perf_event_mmap_output,
7027 * Check whether inode and address range match filter criteria.
7029 static bool perf_addr_filter_match(struct perf_addr_filter *filter,
7030 struct file *file, unsigned long offset,
7033 if (filter->inode != file_inode(file))
7036 if (filter->offset > offset + size)
7039 if (filter->offset + filter->size < offset)
7045 static void __perf_addr_filters_adjust(struct perf_event *event, void *data)
7047 struct perf_addr_filters_head *ifh = perf_event_addr_filters(event);
7048 struct vm_area_struct *vma = data;
7049 unsigned long off = vma->vm_pgoff << PAGE_SHIFT, flags;
7050 struct file *file = vma->vm_file;
7051 struct perf_addr_filter *filter;
7052 unsigned int restart = 0, count = 0;
7054 if (!has_addr_filter(event))
7060 raw_spin_lock_irqsave(&ifh->lock, flags);
7061 list_for_each_entry(filter, &ifh->list, entry) {
7062 if (perf_addr_filter_match(filter, file, off,
7063 vma->vm_end - vma->vm_start)) {
7064 event->addr_filters_offs[count] = vma->vm_start;
7072 event->addr_filters_gen++;
7073 raw_spin_unlock_irqrestore(&ifh->lock, flags);
7076 perf_event_stop(event, 1);
7080 * Adjust all task's events' filters to the new vma
7082 static void perf_addr_filters_adjust(struct vm_area_struct *vma)
7084 struct perf_event_context *ctx;
7088 * Data tracing isn't supported yet and as such there is no need
7089 * to keep track of anything that isn't related to executable code:
7091 if (!(vma->vm_flags & VM_EXEC))
7095 for_each_task_context_nr(ctxn) {
7096 ctx = rcu_dereference(current->perf_event_ctxp[ctxn]);
7100 perf_iterate_ctx(ctx, __perf_addr_filters_adjust, vma, true);
7105 void perf_event_mmap(struct vm_area_struct *vma)
7107 struct perf_mmap_event mmap_event;
7109 if (!atomic_read(&nr_mmap_events))
7112 mmap_event = (struct perf_mmap_event){
7118 .type = PERF_RECORD_MMAP,
7119 .misc = PERF_RECORD_MISC_USER,
7124 .start = vma->vm_start,
7125 .len = vma->vm_end - vma->vm_start,
7126 .pgoff = (u64)vma->vm_pgoff << PAGE_SHIFT,
7128 /* .maj (attr_mmap2 only) */
7129 /* .min (attr_mmap2 only) */
7130 /* .ino (attr_mmap2 only) */
7131 /* .ino_generation (attr_mmap2 only) */
7132 /* .prot (attr_mmap2 only) */
7133 /* .flags (attr_mmap2 only) */
7136 perf_addr_filters_adjust(vma);
7137 perf_event_mmap_event(&mmap_event);
7140 void perf_event_aux_event(struct perf_event *event, unsigned long head,
7141 unsigned long size, u64 flags)
7143 struct perf_output_handle handle;
7144 struct perf_sample_data sample;
7145 struct perf_aux_event {
7146 struct perf_event_header header;
7152 .type = PERF_RECORD_AUX,
7154 .size = sizeof(rec),
7162 perf_event_header__init_id(&rec.header, &sample, event);
7163 ret = perf_output_begin(&handle, event, rec.header.size);
7168 perf_output_put(&handle, rec);
7169 perf_event__output_id_sample(event, &handle, &sample);
7171 perf_output_end(&handle);
7175 * Lost/dropped samples logging
7177 void perf_log_lost_samples(struct perf_event *event, u64 lost)
7179 struct perf_output_handle handle;
7180 struct perf_sample_data sample;
7184 struct perf_event_header header;
7186 } lost_samples_event = {
7188 .type = PERF_RECORD_LOST_SAMPLES,
7190 .size = sizeof(lost_samples_event),
7195 perf_event_header__init_id(&lost_samples_event.header, &sample, event);
7197 ret = perf_output_begin(&handle, event,
7198 lost_samples_event.header.size);
7202 perf_output_put(&handle, lost_samples_event);
7203 perf_event__output_id_sample(event, &handle, &sample);
7204 perf_output_end(&handle);
7208 * context_switch tracking
7211 struct perf_switch_event {
7212 struct task_struct *task;
7213 struct task_struct *next_prev;
7216 struct perf_event_header header;
7222 static int perf_event_switch_match(struct perf_event *event)
7224 return event->attr.context_switch;
7227 static void perf_event_switch_output(struct perf_event *event, void *data)
7229 struct perf_switch_event *se = data;
7230 struct perf_output_handle handle;
7231 struct perf_sample_data sample;
7234 if (!perf_event_switch_match(event))
7237 /* Only CPU-wide events are allowed to see next/prev pid/tid */
7238 if (event->ctx->task) {
7239 se->event_id.header.type = PERF_RECORD_SWITCH;
7240 se->event_id.header.size = sizeof(se->event_id.header);
7242 se->event_id.header.type = PERF_RECORD_SWITCH_CPU_WIDE;
7243 se->event_id.header.size = sizeof(se->event_id);
7244 se->event_id.next_prev_pid =
7245 perf_event_pid(event, se->next_prev);
7246 se->event_id.next_prev_tid =
7247 perf_event_tid(event, se->next_prev);
7250 perf_event_header__init_id(&se->event_id.header, &sample, event);
7252 ret = perf_output_begin(&handle, event, se->event_id.header.size);
7256 if (event->ctx->task)
7257 perf_output_put(&handle, se->event_id.header);
7259 perf_output_put(&handle, se->event_id);
7261 perf_event__output_id_sample(event, &handle, &sample);
7263 perf_output_end(&handle);
7266 static void perf_event_switch(struct task_struct *task,
7267 struct task_struct *next_prev, bool sched_in)
7269 struct perf_switch_event switch_event;
7271 /* N.B. caller checks nr_switch_events != 0 */
7273 switch_event = (struct perf_switch_event){
7275 .next_prev = next_prev,
7279 .misc = sched_in ? 0 : PERF_RECORD_MISC_SWITCH_OUT,
7282 /* .next_prev_pid */
7283 /* .next_prev_tid */
7287 perf_iterate_sb(perf_event_switch_output,
7293 * IRQ throttle logging
7296 static void perf_log_throttle(struct perf_event *event, int enable)
7298 struct perf_output_handle handle;
7299 struct perf_sample_data sample;
7303 struct perf_event_header header;
7307 } throttle_event = {
7309 .type = PERF_RECORD_THROTTLE,
7311 .size = sizeof(throttle_event),
7313 .time = perf_event_clock(event),
7314 .id = primary_event_id(event),
7315 .stream_id = event->id,
7319 throttle_event.header.type = PERF_RECORD_UNTHROTTLE;
7321 perf_event_header__init_id(&throttle_event.header, &sample, event);
7323 ret = perf_output_begin(&handle, event,
7324 throttle_event.header.size);
7328 perf_output_put(&handle, throttle_event);
7329 perf_event__output_id_sample(event, &handle, &sample);
7330 perf_output_end(&handle);
7333 void perf_event_itrace_started(struct perf_event *event)
7335 event->attach_state |= PERF_ATTACH_ITRACE;
7338 static void perf_log_itrace_start(struct perf_event *event)
7340 struct perf_output_handle handle;
7341 struct perf_sample_data sample;
7342 struct perf_aux_event {
7343 struct perf_event_header header;
7350 event = event->parent;
7352 if (!(event->pmu->capabilities & PERF_PMU_CAP_ITRACE) ||
7353 event->attach_state & PERF_ATTACH_ITRACE)
7356 rec.header.type = PERF_RECORD_ITRACE_START;
7357 rec.header.misc = 0;
7358 rec.header.size = sizeof(rec);
7359 rec.pid = perf_event_pid(event, current);
7360 rec.tid = perf_event_tid(event, current);
7362 perf_event_header__init_id(&rec.header, &sample, event);
7363 ret = perf_output_begin(&handle, event, rec.header.size);
7368 perf_output_put(&handle, rec);
7369 perf_event__output_id_sample(event, &handle, &sample);
7371 perf_output_end(&handle);
7375 __perf_event_account_interrupt(struct perf_event *event, int throttle)
7377 struct hw_perf_event *hwc = &event->hw;
7381 seq = __this_cpu_read(perf_throttled_seq);
7382 if (seq != hwc->interrupts_seq) {
7383 hwc->interrupts_seq = seq;
7384 hwc->interrupts = 1;
7387 if (unlikely(throttle
7388 && hwc->interrupts >= max_samples_per_tick)) {
7389 __this_cpu_inc(perf_throttled_count);
7390 tick_dep_set_cpu(smp_processor_id(), TICK_DEP_BIT_PERF_EVENTS);
7391 hwc->interrupts = MAX_INTERRUPTS;
7392 perf_log_throttle(event, 0);
7397 if (event->attr.freq) {
7398 u64 now = perf_clock();
7399 s64 delta = now - hwc->freq_time_stamp;
7401 hwc->freq_time_stamp = now;
7403 if (delta > 0 && delta < 2*TICK_NSEC)
7404 perf_adjust_period(event, delta, hwc->last_period, true);
7410 int perf_event_account_interrupt(struct perf_event *event)
7412 return __perf_event_account_interrupt(event, 1);
7416 * Generic event overflow handling, sampling.
7419 static int __perf_event_overflow(struct perf_event *event,
7420 int throttle, struct perf_sample_data *data,
7421 struct pt_regs *regs)
7423 int events = atomic_read(&event->event_limit);
7427 * Non-sampling counters might still use the PMI to fold short
7428 * hardware counters, ignore those.
7430 if (unlikely(!is_sampling_event(event)))
7433 ret = __perf_event_account_interrupt(event, throttle);
7436 * XXX event_limit might not quite work as expected on inherited
7440 event->pending_kill = POLL_IN;
7441 if (events && atomic_dec_and_test(&event->event_limit)) {
7443 event->pending_kill = POLL_HUP;
7445 perf_event_disable_inatomic(event);
7448 READ_ONCE(event->overflow_handler)(event, data, regs);
7450 if (*perf_event_fasync(event) && event->pending_kill) {
7451 event->pending_wakeup = 1;
7452 irq_work_queue(&event->pending);
7458 int perf_event_overflow(struct perf_event *event,
7459 struct perf_sample_data *data,
7460 struct pt_regs *regs)
7462 return __perf_event_overflow(event, 1, data, regs);
7466 * Generic software event infrastructure
7469 struct swevent_htable {
7470 struct swevent_hlist *swevent_hlist;
7471 struct mutex hlist_mutex;
7474 /* Recursion avoidance in each contexts */
7475 int recursion[PERF_NR_CONTEXTS];
7478 static DEFINE_PER_CPU(struct swevent_htable, swevent_htable);
7481 * We directly increment event->count and keep a second value in
7482 * event->hw.period_left to count intervals. This period event
7483 * is kept in the range [-sample_period, 0] so that we can use the
7487 u64 perf_swevent_set_period(struct perf_event *event)
7489 struct hw_perf_event *hwc = &event->hw;
7490 u64 period = hwc->last_period;
7494 hwc->last_period = hwc->sample_period;
7497 old = val = local64_read(&hwc->period_left);
7501 nr = div64_u64(period + val, period);
7502 offset = nr * period;
7504 if (local64_cmpxchg(&hwc->period_left, old, val) != old)
7510 static void perf_swevent_overflow(struct perf_event *event, u64 overflow,
7511 struct perf_sample_data *data,
7512 struct pt_regs *regs)
7514 struct hw_perf_event *hwc = &event->hw;
7518 overflow = perf_swevent_set_period(event);
7520 if (hwc->interrupts == MAX_INTERRUPTS)
7523 for (; overflow; overflow--) {
7524 if (__perf_event_overflow(event, throttle,
7527 * We inhibit the overflow from happening when
7528 * hwc->interrupts == MAX_INTERRUPTS.
7536 static void perf_swevent_event(struct perf_event *event, u64 nr,
7537 struct perf_sample_data *data,
7538 struct pt_regs *regs)
7540 struct hw_perf_event *hwc = &event->hw;
7542 local64_add(nr, &event->count);
7547 if (!is_sampling_event(event))
7550 if ((event->attr.sample_type & PERF_SAMPLE_PERIOD) && !event->attr.freq) {
7552 return perf_swevent_overflow(event, 1, data, regs);
7554 data->period = event->hw.last_period;
7556 if (nr == 1 && hwc->sample_period == 1 && !event->attr.freq)
7557 return perf_swevent_overflow(event, 1, data, regs);
7559 if (local64_add_negative(nr, &hwc->period_left))
7562 perf_swevent_overflow(event, 0, data, regs);
7565 static int perf_exclude_event(struct perf_event *event,
7566 struct pt_regs *regs)
7568 if (event->hw.state & PERF_HES_STOPPED)
7572 if (event->attr.exclude_user && user_mode(regs))
7575 if (event->attr.exclude_kernel && !user_mode(regs))
7582 static int perf_swevent_match(struct perf_event *event,
7583 enum perf_type_id type,
7585 struct perf_sample_data *data,
7586 struct pt_regs *regs)
7588 if (event->attr.type != type)
7591 if (event->attr.config != event_id)
7594 if (perf_exclude_event(event, regs))
7600 static inline u64 swevent_hash(u64 type, u32 event_id)
7602 u64 val = event_id | (type << 32);
7604 return hash_64(val, SWEVENT_HLIST_BITS);
7607 static inline struct hlist_head *
7608 __find_swevent_head(struct swevent_hlist *hlist, u64 type, u32 event_id)
7610 u64 hash = swevent_hash(type, event_id);
7612 return &hlist->heads[hash];
7615 /* For the read side: events when they trigger */
7616 static inline struct hlist_head *
7617 find_swevent_head_rcu(struct swevent_htable *swhash, u64 type, u32 event_id)
7619 struct swevent_hlist *hlist;
7621 hlist = rcu_dereference(swhash->swevent_hlist);
7625 return __find_swevent_head(hlist, type, event_id);
7628 /* For the event head insertion and removal in the hlist */
7629 static inline struct hlist_head *
7630 find_swevent_head(struct swevent_htable *swhash, struct perf_event *event)
7632 struct swevent_hlist *hlist;
7633 u32 event_id = event->attr.config;
7634 u64 type = event->attr.type;
7637 * Event scheduling is always serialized against hlist allocation
7638 * and release. Which makes the protected version suitable here.
7639 * The context lock guarantees that.
7641 hlist = rcu_dereference_protected(swhash->swevent_hlist,
7642 lockdep_is_held(&event->ctx->lock));
7646 return __find_swevent_head(hlist, type, event_id);
7649 static void do_perf_sw_event(enum perf_type_id type, u32 event_id,
7651 struct perf_sample_data *data,
7652 struct pt_regs *regs)
7654 struct swevent_htable *swhash = this_cpu_ptr(&swevent_htable);
7655 struct perf_event *event;
7656 struct hlist_head *head;
7659 head = find_swevent_head_rcu(swhash, type, event_id);
7663 hlist_for_each_entry_rcu(event, head, hlist_entry) {
7664 if (perf_swevent_match(event, type, event_id, data, regs))
7665 perf_swevent_event(event, nr, data, regs);
7671 DEFINE_PER_CPU(struct pt_regs, __perf_regs[4]);
7673 int perf_swevent_get_recursion_context(void)
7675 struct swevent_htable *swhash = this_cpu_ptr(&swevent_htable);
7677 return get_recursion_context(swhash->recursion);
7679 EXPORT_SYMBOL_GPL(perf_swevent_get_recursion_context);
7681 void perf_swevent_put_recursion_context(int rctx)
7683 struct swevent_htable *swhash = this_cpu_ptr(&swevent_htable);
7685 put_recursion_context(swhash->recursion, rctx);
7688 void ___perf_sw_event(u32 event_id, u64 nr, struct pt_regs *regs, u64 addr)
7690 struct perf_sample_data data;
7692 if (WARN_ON_ONCE(!regs))
7695 perf_sample_data_init(&data, addr, 0);
7696 do_perf_sw_event(PERF_TYPE_SOFTWARE, event_id, nr, &data, regs);
7699 void __perf_sw_event(u32 event_id, u64 nr, struct pt_regs *regs, u64 addr)
7703 preempt_disable_notrace();
7704 rctx = perf_swevent_get_recursion_context();
7705 if (unlikely(rctx < 0))
7708 ___perf_sw_event(event_id, nr, regs, addr);
7710 perf_swevent_put_recursion_context(rctx);
7712 preempt_enable_notrace();
7715 static void perf_swevent_read(struct perf_event *event)
7719 static int perf_swevent_add(struct perf_event *event, int flags)
7721 struct swevent_htable *swhash = this_cpu_ptr(&swevent_htable);
7722 struct hw_perf_event *hwc = &event->hw;
7723 struct hlist_head *head;
7725 if (is_sampling_event(event)) {
7726 hwc->last_period = hwc->sample_period;
7727 perf_swevent_set_period(event);
7730 hwc->state = !(flags & PERF_EF_START);
7732 head = find_swevent_head(swhash, event);
7733 if (WARN_ON_ONCE(!head))
7736 hlist_add_head_rcu(&event->hlist_entry, head);
7737 perf_event_update_userpage(event);
7742 static void perf_swevent_del(struct perf_event *event, int flags)
7744 hlist_del_rcu(&event->hlist_entry);
7747 static void perf_swevent_start(struct perf_event *event, int flags)
7749 event->hw.state = 0;
7752 static void perf_swevent_stop(struct perf_event *event, int flags)
7754 event->hw.state = PERF_HES_STOPPED;
7757 /* Deref the hlist from the update side */
7758 static inline struct swevent_hlist *
7759 swevent_hlist_deref(struct swevent_htable *swhash)
7761 return rcu_dereference_protected(swhash->swevent_hlist,
7762 lockdep_is_held(&swhash->hlist_mutex));
7765 static void swevent_hlist_release(struct swevent_htable *swhash)
7767 struct swevent_hlist *hlist = swevent_hlist_deref(swhash);
7772 RCU_INIT_POINTER(swhash->swevent_hlist, NULL);
7773 kfree_rcu(hlist, rcu_head);
7776 static void swevent_hlist_put_cpu(int cpu)
7778 struct swevent_htable *swhash = &per_cpu(swevent_htable, cpu);
7780 mutex_lock(&swhash->hlist_mutex);
7782 if (!--swhash->hlist_refcount)
7783 swevent_hlist_release(swhash);
7785 mutex_unlock(&swhash->hlist_mutex);
7788 static void swevent_hlist_put(void)
7792 for_each_possible_cpu(cpu)
7793 swevent_hlist_put_cpu(cpu);
7796 static int swevent_hlist_get_cpu(int cpu)
7798 struct swevent_htable *swhash = &per_cpu(swevent_htable, cpu);
7801 mutex_lock(&swhash->hlist_mutex);
7802 if (!swevent_hlist_deref(swhash) &&
7803 cpumask_test_cpu(cpu, perf_online_mask)) {
7804 struct swevent_hlist *hlist;
7806 hlist = kzalloc(sizeof(*hlist), GFP_KERNEL);
7811 rcu_assign_pointer(swhash->swevent_hlist, hlist);
7813 swhash->hlist_refcount++;
7815 mutex_unlock(&swhash->hlist_mutex);
7820 static int swevent_hlist_get(void)
7822 int err, cpu, failed_cpu;
7824 mutex_lock(&pmus_lock);
7825 for_each_possible_cpu(cpu) {
7826 err = swevent_hlist_get_cpu(cpu);
7832 mutex_unlock(&pmus_lock);
7835 for_each_possible_cpu(cpu) {
7836 if (cpu == failed_cpu)
7838 swevent_hlist_put_cpu(cpu);
7840 mutex_unlock(&pmus_lock);
7844 struct static_key perf_swevent_enabled[PERF_COUNT_SW_MAX];
7846 static void sw_perf_event_destroy(struct perf_event *event)
7848 u64 event_id = event->attr.config;
7850 WARN_ON(event->parent);
7852 static_key_slow_dec(&perf_swevent_enabled[event_id]);
7853 swevent_hlist_put();
7856 static int perf_swevent_init(struct perf_event *event)
7858 u64 event_id = event->attr.config;
7860 if (event->attr.type != PERF_TYPE_SOFTWARE)
7864 * no branch sampling for software events
7866 if (has_branch_stack(event))
7870 case PERF_COUNT_SW_CPU_CLOCK:
7871 case PERF_COUNT_SW_TASK_CLOCK:
7878 if (event_id >= PERF_COUNT_SW_MAX)
7881 if (!event->parent) {
7884 err = swevent_hlist_get();
7888 static_key_slow_inc(&perf_swevent_enabled[event_id]);
7889 event->destroy = sw_perf_event_destroy;
7895 static struct pmu perf_swevent = {
7896 .task_ctx_nr = perf_sw_context,
7898 .capabilities = PERF_PMU_CAP_NO_NMI,
7900 .event_init = perf_swevent_init,
7901 .add = perf_swevent_add,
7902 .del = perf_swevent_del,
7903 .start = perf_swevent_start,
7904 .stop = perf_swevent_stop,
7905 .read = perf_swevent_read,
7908 #ifdef CONFIG_EVENT_TRACING
7910 static int perf_tp_filter_match(struct perf_event *event,
7911 struct perf_sample_data *data)
7913 void *record = data->raw->frag.data;
7915 /* only top level events have filters set */
7917 event = event->parent;
7919 if (likely(!event->filter) || filter_match_preds(event->filter, record))
7924 static int perf_tp_event_match(struct perf_event *event,
7925 struct perf_sample_data *data,
7926 struct pt_regs *regs)
7928 if (event->hw.state & PERF_HES_STOPPED)
7931 * All tracepoints are from kernel-space.
7933 if (event->attr.exclude_kernel)
7936 if (!perf_tp_filter_match(event, data))
7942 void perf_trace_run_bpf_submit(void *raw_data, int size, int rctx,
7943 struct trace_event_call *call, u64 count,
7944 struct pt_regs *regs, struct hlist_head *head,
7945 struct task_struct *task)
7947 struct bpf_prog *prog = call->prog;
7950 *(struct pt_regs **)raw_data = regs;
7951 if (!trace_call_bpf(prog, raw_data) || hlist_empty(head)) {
7952 perf_swevent_put_recursion_context(rctx);
7956 perf_tp_event(call->event.type, count, raw_data, size, regs, head,
7959 EXPORT_SYMBOL_GPL(perf_trace_run_bpf_submit);
7961 void perf_tp_event(u16 event_type, u64 count, void *record, int entry_size,
7962 struct pt_regs *regs, struct hlist_head *head, int rctx,
7963 struct task_struct *task, struct perf_event *event)
7965 struct perf_sample_data data;
7967 struct perf_raw_record raw = {
7974 perf_sample_data_init(&data, 0, 0);
7977 perf_trace_buf_update(record, event_type);
7979 /* Use the given event instead of the hlist */
7981 if (perf_tp_event_match(event, &data, regs))
7982 perf_swevent_event(event, count, &data, regs);
7984 hlist_for_each_entry_rcu(event, head, hlist_entry) {
7985 if (perf_tp_event_match(event, &data, regs))
7986 perf_swevent_event(event, count, &data, regs);
7991 * If we got specified a target task, also iterate its context and
7992 * deliver this event there too.
7994 if (task && task != current) {
7995 struct perf_event_context *ctx;
7996 struct trace_entry *entry = record;
7999 ctx = rcu_dereference(task->perf_event_ctxp[perf_sw_context]);
8003 list_for_each_entry_rcu(event, &ctx->event_list, event_entry) {
8004 if (event->attr.type != PERF_TYPE_TRACEPOINT)
8006 if (event->attr.config != entry->type)
8008 if (perf_tp_event_match(event, &data, regs))
8009 perf_swevent_event(event, count, &data, regs);
8015 perf_swevent_put_recursion_context(rctx);
8017 EXPORT_SYMBOL_GPL(perf_tp_event);
8019 static void tp_perf_event_destroy(struct perf_event *event)
8021 perf_trace_destroy(event);
8024 static int perf_tp_event_init(struct perf_event *event)
8028 if (event->attr.type != PERF_TYPE_TRACEPOINT)
8032 * no branch sampling for tracepoint events
8034 if (has_branch_stack(event))
8037 err = perf_trace_init(event);
8041 event->destroy = tp_perf_event_destroy;
8046 static struct pmu perf_tracepoint = {
8047 .task_ctx_nr = perf_sw_context,
8049 .event_init = perf_tp_event_init,
8050 .add = perf_trace_add,
8051 .del = perf_trace_del,
8052 .start = perf_swevent_start,
8053 .stop = perf_swevent_stop,
8054 .read = perf_swevent_read,
8057 static inline void perf_tp_register(void)
8059 perf_pmu_register(&perf_tracepoint, "tracepoint", PERF_TYPE_TRACEPOINT);
8062 static void perf_event_free_filter(struct perf_event *event)
8064 ftrace_profile_free_filter(event);
8067 #ifdef CONFIG_BPF_SYSCALL
8068 static void bpf_overflow_handler(struct perf_event *event,
8069 struct perf_sample_data *data,
8070 struct pt_regs *regs)
8072 struct bpf_perf_event_data_kern ctx = {
8079 if (unlikely(__this_cpu_inc_return(bpf_prog_active) != 1))
8082 ret = BPF_PROG_RUN(event->prog, &ctx);
8085 __this_cpu_dec(bpf_prog_active);
8090 event->orig_overflow_handler(event, data, regs);
8093 static int perf_event_set_bpf_handler(struct perf_event *event, u32 prog_fd)
8095 struct bpf_prog *prog;
8097 if (event->overflow_handler_context)
8098 /* hw breakpoint or kernel counter */
8104 prog = bpf_prog_get_type(prog_fd, BPF_PROG_TYPE_PERF_EVENT);
8106 return PTR_ERR(prog);
8109 event->orig_overflow_handler = READ_ONCE(event->overflow_handler);
8110 WRITE_ONCE(event->overflow_handler, bpf_overflow_handler);
8114 static void perf_event_free_bpf_handler(struct perf_event *event)
8116 struct bpf_prog *prog = event->prog;
8121 WRITE_ONCE(event->overflow_handler, event->orig_overflow_handler);
8126 static int perf_event_set_bpf_handler(struct perf_event *event, u32 prog_fd)
8130 static void perf_event_free_bpf_handler(struct perf_event *event)
8135 static int perf_event_set_bpf_prog(struct perf_event *event, u32 prog_fd)
8137 bool is_kprobe, is_tracepoint, is_syscall_tp;
8138 struct bpf_prog *prog;
8140 if (event->attr.type != PERF_TYPE_TRACEPOINT)
8141 return perf_event_set_bpf_handler(event, prog_fd);
8143 if (event->tp_event->prog)
8146 is_kprobe = event->tp_event->flags & TRACE_EVENT_FL_UKPROBE;
8147 is_tracepoint = event->tp_event->flags & TRACE_EVENT_FL_TRACEPOINT;
8148 is_syscall_tp = is_syscall_trace_event(event->tp_event);
8149 if (!is_kprobe && !is_tracepoint && !is_syscall_tp)
8150 /* bpf programs can only be attached to u/kprobe or tracepoint */
8153 prog = bpf_prog_get(prog_fd);
8155 return PTR_ERR(prog);
8157 if ((is_kprobe && prog->type != BPF_PROG_TYPE_KPROBE) ||
8158 (is_tracepoint && prog->type != BPF_PROG_TYPE_TRACEPOINT) ||
8159 (is_syscall_tp && prog->type != BPF_PROG_TYPE_TRACEPOINT)) {
8160 /* valid fd, but invalid bpf program type */
8165 if (is_tracepoint || is_syscall_tp) {
8166 int off = trace_event_get_offsets(event->tp_event);
8168 if (prog->aux->max_ctx_offset > off) {
8173 event->tp_event->prog = prog;
8174 event->tp_event->bpf_prog_owner = event;
8179 static void perf_event_free_bpf_prog(struct perf_event *event)
8181 struct bpf_prog *prog;
8183 perf_event_free_bpf_handler(event);
8185 if (!event->tp_event)
8188 prog = event->tp_event->prog;
8189 if (prog && event->tp_event->bpf_prog_owner == event) {
8190 event->tp_event->prog = NULL;
8197 static inline void perf_tp_register(void)
8201 static void perf_event_free_filter(struct perf_event *event)
8205 static int perf_event_set_bpf_prog(struct perf_event *event, u32 prog_fd)
8210 static void perf_event_free_bpf_prog(struct perf_event *event)
8213 #endif /* CONFIG_EVENT_TRACING */
8215 #ifdef CONFIG_HAVE_HW_BREAKPOINT
8216 void perf_bp_event(struct perf_event *bp, void *data)
8218 struct perf_sample_data sample;
8219 struct pt_regs *regs = data;
8221 perf_sample_data_init(&sample, bp->attr.bp_addr, 0);
8223 if (!bp->hw.state && !perf_exclude_event(bp, regs))
8224 perf_swevent_event(bp, 1, &sample, regs);
8229 * Allocate a new address filter
8231 static struct perf_addr_filter *
8232 perf_addr_filter_new(struct perf_event *event, struct list_head *filters)
8234 int node = cpu_to_node(event->cpu == -1 ? 0 : event->cpu);
8235 struct perf_addr_filter *filter;
8237 filter = kzalloc_node(sizeof(*filter), GFP_KERNEL, node);
8241 INIT_LIST_HEAD(&filter->entry);
8242 list_add_tail(&filter->entry, filters);
8247 static void free_filters_list(struct list_head *filters)
8249 struct perf_addr_filter *filter, *iter;
8251 list_for_each_entry_safe(filter, iter, filters, entry) {
8253 iput(filter->inode);
8254 list_del(&filter->entry);
8260 * Free existing address filters and optionally install new ones
8262 static void perf_addr_filters_splice(struct perf_event *event,
8263 struct list_head *head)
8265 unsigned long flags;
8268 if (!has_addr_filter(event))
8271 /* don't bother with children, they don't have their own filters */
8275 raw_spin_lock_irqsave(&event->addr_filters.lock, flags);
8277 list_splice_init(&event->addr_filters.list, &list);
8279 list_splice(head, &event->addr_filters.list);
8281 raw_spin_unlock_irqrestore(&event->addr_filters.lock, flags);
8283 free_filters_list(&list);
8287 * Scan through mm's vmas and see if one of them matches the
8288 * @filter; if so, adjust filter's address range.
8289 * Called with mm::mmap_sem down for reading.
8291 static unsigned long perf_addr_filter_apply(struct perf_addr_filter *filter,
8292 struct mm_struct *mm)
8294 struct vm_area_struct *vma;
8296 for (vma = mm->mmap; vma; vma = vma->vm_next) {
8297 struct file *file = vma->vm_file;
8298 unsigned long off = vma->vm_pgoff << PAGE_SHIFT;
8299 unsigned long vma_size = vma->vm_end - vma->vm_start;
8304 if (!perf_addr_filter_match(filter, file, off, vma_size))
8307 return vma->vm_start;
8314 * Update event's address range filters based on the
8315 * task's existing mappings, if any.
8317 static void perf_event_addr_filters_apply(struct perf_event *event)
8319 struct perf_addr_filters_head *ifh = perf_event_addr_filters(event);
8320 struct task_struct *task = READ_ONCE(event->ctx->task);
8321 struct perf_addr_filter *filter;
8322 struct mm_struct *mm = NULL;
8323 unsigned int count = 0;
8324 unsigned long flags;
8327 * We may observe TASK_TOMBSTONE, which means that the event tear-down
8328 * will stop on the parent's child_mutex that our caller is also holding
8330 if (task == TASK_TOMBSTONE)
8333 if (!ifh->nr_file_filters)
8336 mm = get_task_mm(event->ctx->task);
8340 down_read(&mm->mmap_sem);
8342 raw_spin_lock_irqsave(&ifh->lock, flags);
8343 list_for_each_entry(filter, &ifh->list, entry) {
8344 event->addr_filters_offs[count] = 0;
8347 * Adjust base offset if the filter is associated to a binary
8348 * that needs to be mapped:
8351 event->addr_filters_offs[count] =
8352 perf_addr_filter_apply(filter, mm);
8357 event->addr_filters_gen++;
8358 raw_spin_unlock_irqrestore(&ifh->lock, flags);
8360 up_read(&mm->mmap_sem);
8365 perf_event_stop(event, 1);
8369 * Address range filtering: limiting the data to certain
8370 * instruction address ranges. Filters are ioctl()ed to us from
8371 * userspace as ascii strings.
8373 * Filter string format:
8376 * where ACTION is one of the
8377 * * "filter": limit the trace to this region
8378 * * "start": start tracing from this address
8379 * * "stop": stop tracing at this address/region;
8381 * * for kernel addresses: <start address>[/<size>]
8382 * * for object files: <start address>[/<size>]@</path/to/object/file>
8384 * if <size> is not specified, the range is treated as a single address.
8398 IF_STATE_ACTION = 0,
8403 static const match_table_t if_tokens = {
8404 { IF_ACT_FILTER, "filter" },
8405 { IF_ACT_START, "start" },
8406 { IF_ACT_STOP, "stop" },
8407 { IF_SRC_FILE, "%u/%u@%s" },
8408 { IF_SRC_KERNEL, "%u/%u" },
8409 { IF_SRC_FILEADDR, "%u@%s" },
8410 { IF_SRC_KERNELADDR, "%u" },
8411 { IF_ACT_NONE, NULL },
8415 * Address filter string parser
8418 perf_event_parse_addr_filter(struct perf_event *event, char *fstr,
8419 struct list_head *filters)
8421 struct perf_addr_filter *filter = NULL;
8422 char *start, *orig, *filename = NULL;
8424 substring_t args[MAX_OPT_ARGS];
8425 int state = IF_STATE_ACTION, token;
8426 unsigned int kernel = 0;
8429 orig = fstr = kstrdup(fstr, GFP_KERNEL);
8433 while ((start = strsep(&fstr, " ,\n")) != NULL) {
8439 /* filter definition begins */
8440 if (state == IF_STATE_ACTION) {
8441 filter = perf_addr_filter_new(event, filters);
8446 token = match_token(start, if_tokens, args);
8453 if (state != IF_STATE_ACTION)
8456 state = IF_STATE_SOURCE;
8459 case IF_SRC_KERNELADDR:
8463 case IF_SRC_FILEADDR:
8465 if (state != IF_STATE_SOURCE)
8468 if (token == IF_SRC_FILE || token == IF_SRC_KERNEL)
8472 ret = kstrtoul(args[0].from, 0, &filter->offset);
8476 if (filter->range) {
8478 ret = kstrtoul(args[1].from, 0, &filter->size);
8483 if (token == IF_SRC_FILE || token == IF_SRC_FILEADDR) {
8484 int fpos = filter->range ? 2 : 1;
8486 filename = match_strdup(&args[fpos]);
8493 state = IF_STATE_END;
8501 * Filter definition is fully parsed, validate and install it.
8502 * Make sure that it doesn't contradict itself or the event's
8505 if (state == IF_STATE_END) {
8507 if (kernel && event->attr.exclude_kernel)
8515 * For now, we only support file-based filters
8516 * in per-task events; doing so for CPU-wide
8517 * events requires additional context switching
8518 * trickery, since same object code will be
8519 * mapped at different virtual addresses in
8520 * different processes.
8523 if (!event->ctx->task)
8524 goto fail_free_name;
8526 /* look up the path and grab its inode */
8527 ret = kern_path(filename, LOOKUP_FOLLOW, &path);
8529 goto fail_free_name;
8531 filter->inode = igrab(d_inode(path.dentry));
8537 if (!filter->inode ||
8538 !S_ISREG(filter->inode->i_mode))
8539 /* free_filters_list() will iput() */
8542 event->addr_filters.nr_file_filters++;
8545 /* ready to consume more filters */
8546 state = IF_STATE_ACTION;
8551 if (state != IF_STATE_ACTION)
8561 free_filters_list(filters);
8568 perf_event_set_addr_filter(struct perf_event *event, char *filter_str)
8574 * Since this is called in perf_ioctl() path, we're already holding
8577 lockdep_assert_held(&event->ctx->mutex);
8579 if (WARN_ON_ONCE(event->parent))
8582 ret = perf_event_parse_addr_filter(event, filter_str, &filters);
8584 goto fail_clear_files;
8586 ret = event->pmu->addr_filters_validate(&filters);
8588 goto fail_free_filters;
8590 /* remove existing filters, if any */
8591 perf_addr_filters_splice(event, &filters);
8593 /* install new filters */
8594 perf_event_for_each_child(event, perf_event_addr_filters_apply);
8599 free_filters_list(&filters);
8602 event->addr_filters.nr_file_filters = 0;
8607 static int perf_event_set_filter(struct perf_event *event, void __user *arg)
8612 if ((event->attr.type != PERF_TYPE_TRACEPOINT ||
8613 !IS_ENABLED(CONFIG_EVENT_TRACING)) &&
8614 !has_addr_filter(event))
8617 filter_str = strndup_user(arg, PAGE_SIZE);
8618 if (IS_ERR(filter_str))
8619 return PTR_ERR(filter_str);
8621 if (IS_ENABLED(CONFIG_EVENT_TRACING) &&
8622 event->attr.type == PERF_TYPE_TRACEPOINT)
8623 ret = ftrace_profile_set_filter(event, event->attr.config,
8625 else if (has_addr_filter(event))
8626 ret = perf_event_set_addr_filter(event, filter_str);
8633 * hrtimer based swevent callback
8636 static enum hrtimer_restart perf_swevent_hrtimer(struct hrtimer *hrtimer)
8638 enum hrtimer_restart ret = HRTIMER_RESTART;
8639 struct perf_sample_data data;
8640 struct pt_regs *regs;
8641 struct perf_event *event;
8644 event = container_of(hrtimer, struct perf_event, hw.hrtimer);
8646 if (event->state != PERF_EVENT_STATE_ACTIVE)
8647 return HRTIMER_NORESTART;
8649 event->pmu->read(event);
8651 perf_sample_data_init(&data, 0, event->hw.last_period);
8652 regs = get_irq_regs();
8654 if (regs && !perf_exclude_event(event, regs)) {
8655 if (!(event->attr.exclude_idle && is_idle_task(current)))
8656 if (__perf_event_overflow(event, 1, &data, regs))
8657 ret = HRTIMER_NORESTART;
8660 period = max_t(u64, 10000, event->hw.sample_period);
8661 hrtimer_forward_now(hrtimer, ns_to_ktime(period));
8666 static void perf_swevent_start_hrtimer(struct perf_event *event)
8668 struct hw_perf_event *hwc = &event->hw;
8671 if (!is_sampling_event(event))
8674 period = local64_read(&hwc->period_left);
8679 local64_set(&hwc->period_left, 0);
8681 period = max_t(u64, 10000, hwc->sample_period);
8683 hrtimer_start(&hwc->hrtimer, ns_to_ktime(period),
8684 HRTIMER_MODE_REL_PINNED);
8687 static void perf_swevent_cancel_hrtimer(struct perf_event *event)
8689 struct hw_perf_event *hwc = &event->hw;
8691 if (is_sampling_event(event)) {
8692 ktime_t remaining = hrtimer_get_remaining(&hwc->hrtimer);
8693 local64_set(&hwc->period_left, ktime_to_ns(remaining));
8695 hrtimer_cancel(&hwc->hrtimer);
8699 static void perf_swevent_init_hrtimer(struct perf_event *event)
8701 struct hw_perf_event *hwc = &event->hw;
8703 if (!is_sampling_event(event))
8706 hrtimer_init(&hwc->hrtimer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
8707 hwc->hrtimer.function = perf_swevent_hrtimer;
8710 * Since hrtimers have a fixed rate, we can do a static freq->period
8711 * mapping and avoid the whole period adjust feedback stuff.
8713 if (event->attr.freq) {
8714 long freq = event->attr.sample_freq;
8716 event->attr.sample_period = NSEC_PER_SEC / freq;
8717 hwc->sample_period = event->attr.sample_period;
8718 local64_set(&hwc->period_left, hwc->sample_period);
8719 hwc->last_period = hwc->sample_period;
8720 event->attr.freq = 0;
8725 * Software event: cpu wall time clock
8728 static void cpu_clock_event_update(struct perf_event *event)
8733 now = local_clock();
8734 prev = local64_xchg(&event->hw.prev_count, now);
8735 local64_add(now - prev, &event->count);
8738 static void cpu_clock_event_start(struct perf_event *event, int flags)
8740 local64_set(&event->hw.prev_count, local_clock());
8741 perf_swevent_start_hrtimer(event);
8744 static void cpu_clock_event_stop(struct perf_event *event, int flags)
8746 perf_swevent_cancel_hrtimer(event);
8747 cpu_clock_event_update(event);
8750 static int cpu_clock_event_add(struct perf_event *event, int flags)
8752 if (flags & PERF_EF_START)
8753 cpu_clock_event_start(event, flags);
8754 perf_event_update_userpage(event);
8759 static void cpu_clock_event_del(struct perf_event *event, int flags)
8761 cpu_clock_event_stop(event, flags);
8764 static void cpu_clock_event_read(struct perf_event *event)
8766 cpu_clock_event_update(event);
8769 static int cpu_clock_event_init(struct perf_event *event)
8771 if (event->attr.type != PERF_TYPE_SOFTWARE)
8774 if (event->attr.config != PERF_COUNT_SW_CPU_CLOCK)
8778 * no branch sampling for software events
8780 if (has_branch_stack(event))
8783 perf_swevent_init_hrtimer(event);
8788 static struct pmu perf_cpu_clock = {
8789 .task_ctx_nr = perf_sw_context,
8791 .capabilities = PERF_PMU_CAP_NO_NMI,
8793 .event_init = cpu_clock_event_init,
8794 .add = cpu_clock_event_add,
8795 .del = cpu_clock_event_del,
8796 .start = cpu_clock_event_start,
8797 .stop = cpu_clock_event_stop,
8798 .read = cpu_clock_event_read,
8802 * Software event: task time clock
8805 static void task_clock_event_update(struct perf_event *event, u64 now)
8810 prev = local64_xchg(&event->hw.prev_count, now);
8812 local64_add(delta, &event->count);
8815 static void task_clock_event_start(struct perf_event *event, int flags)
8817 local64_set(&event->hw.prev_count, event->ctx->time);
8818 perf_swevent_start_hrtimer(event);
8821 static void task_clock_event_stop(struct perf_event *event, int flags)
8823 perf_swevent_cancel_hrtimer(event);
8824 task_clock_event_update(event, event->ctx->time);
8827 static int task_clock_event_add(struct perf_event *event, int flags)
8829 if (flags & PERF_EF_START)
8830 task_clock_event_start(event, flags);
8831 perf_event_update_userpage(event);
8836 static void task_clock_event_del(struct perf_event *event, int flags)
8838 task_clock_event_stop(event, PERF_EF_UPDATE);
8841 static void task_clock_event_read(struct perf_event *event)
8843 u64 now = perf_clock();
8844 u64 delta = now - event->ctx->timestamp;
8845 u64 time = event->ctx->time + delta;
8847 task_clock_event_update(event, time);
8850 static int task_clock_event_init(struct perf_event *event)
8852 if (event->attr.type != PERF_TYPE_SOFTWARE)
8855 if (event->attr.config != PERF_COUNT_SW_TASK_CLOCK)
8859 * no branch sampling for software events
8861 if (has_branch_stack(event))
8864 perf_swevent_init_hrtimer(event);
8869 static struct pmu perf_task_clock = {
8870 .task_ctx_nr = perf_sw_context,
8872 .capabilities = PERF_PMU_CAP_NO_NMI,
8874 .event_init = task_clock_event_init,
8875 .add = task_clock_event_add,
8876 .del = task_clock_event_del,
8877 .start = task_clock_event_start,
8878 .stop = task_clock_event_stop,
8879 .read = task_clock_event_read,
8882 static void perf_pmu_nop_void(struct pmu *pmu)
8886 static void perf_pmu_nop_txn(struct pmu *pmu, unsigned int flags)
8890 static int perf_pmu_nop_int(struct pmu *pmu)
8895 static DEFINE_PER_CPU(unsigned int, nop_txn_flags);
8897 static void perf_pmu_start_txn(struct pmu *pmu, unsigned int flags)
8899 __this_cpu_write(nop_txn_flags, flags);
8901 if (flags & ~PERF_PMU_TXN_ADD)
8904 perf_pmu_disable(pmu);
8907 static int perf_pmu_commit_txn(struct pmu *pmu)
8909 unsigned int flags = __this_cpu_read(nop_txn_flags);
8911 __this_cpu_write(nop_txn_flags, 0);
8913 if (flags & ~PERF_PMU_TXN_ADD)
8916 perf_pmu_enable(pmu);
8920 static void perf_pmu_cancel_txn(struct pmu *pmu)
8922 unsigned int flags = __this_cpu_read(nop_txn_flags);
8924 __this_cpu_write(nop_txn_flags, 0);
8926 if (flags & ~PERF_PMU_TXN_ADD)
8929 perf_pmu_enable(pmu);
8932 static int perf_event_idx_default(struct perf_event *event)
8938 * Ensures all contexts with the same task_ctx_nr have the same
8939 * pmu_cpu_context too.
8941 static struct perf_cpu_context __percpu *find_pmu_context(int ctxn)
8948 list_for_each_entry(pmu, &pmus, entry) {
8949 if (pmu->task_ctx_nr == ctxn)
8950 return pmu->pmu_cpu_context;
8956 static void free_pmu_context(struct pmu *pmu)
8958 mutex_lock(&pmus_lock);
8959 free_percpu(pmu->pmu_cpu_context);
8960 mutex_unlock(&pmus_lock);
8964 * Let userspace know that this PMU supports address range filtering:
8966 static ssize_t nr_addr_filters_show(struct device *dev,
8967 struct device_attribute *attr,
8970 struct pmu *pmu = dev_get_drvdata(dev);
8972 return snprintf(page, PAGE_SIZE - 1, "%d\n", pmu->nr_addr_filters);
8974 DEVICE_ATTR_RO(nr_addr_filters);
8976 static struct idr pmu_idr;
8979 type_show(struct device *dev, struct device_attribute *attr, char *page)
8981 struct pmu *pmu = dev_get_drvdata(dev);
8983 return snprintf(page, PAGE_SIZE-1, "%d\n", pmu->type);
8985 static DEVICE_ATTR_RO(type);
8988 perf_event_mux_interval_ms_show(struct device *dev,
8989 struct device_attribute *attr,
8992 struct pmu *pmu = dev_get_drvdata(dev);
8994 return snprintf(page, PAGE_SIZE-1, "%d\n", pmu->hrtimer_interval_ms);
8997 static DEFINE_MUTEX(mux_interval_mutex);
9000 perf_event_mux_interval_ms_store(struct device *dev,
9001 struct device_attribute *attr,
9002 const char *buf, size_t count)
9004 struct pmu *pmu = dev_get_drvdata(dev);
9005 int timer, cpu, ret;
9007 ret = kstrtoint(buf, 0, &timer);
9014 /* same value, noting to do */
9015 if (timer == pmu->hrtimer_interval_ms)
9018 mutex_lock(&mux_interval_mutex);
9019 pmu->hrtimer_interval_ms = timer;
9021 /* update all cpuctx for this PMU */
9023 for_each_online_cpu(cpu) {
9024 struct perf_cpu_context *cpuctx;
9025 cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
9026 cpuctx->hrtimer_interval = ns_to_ktime(NSEC_PER_MSEC * timer);
9028 cpu_function_call(cpu,
9029 (remote_function_f)perf_mux_hrtimer_restart, cpuctx);
9032 mutex_unlock(&mux_interval_mutex);
9036 static DEVICE_ATTR_RW(perf_event_mux_interval_ms);
9038 static struct attribute *pmu_dev_attrs[] = {
9039 &dev_attr_type.attr,
9040 &dev_attr_perf_event_mux_interval_ms.attr,
9043 ATTRIBUTE_GROUPS(pmu_dev);
9045 static int pmu_bus_running;
9046 static struct bus_type pmu_bus = {
9047 .name = "event_source",
9048 .dev_groups = pmu_dev_groups,
9051 static void pmu_dev_release(struct device *dev)
9056 static int pmu_dev_alloc(struct pmu *pmu)
9060 pmu->dev = kzalloc(sizeof(struct device), GFP_KERNEL);
9064 pmu->dev->groups = pmu->attr_groups;
9065 device_initialize(pmu->dev);
9066 ret = dev_set_name(pmu->dev, "%s", pmu->name);
9070 dev_set_drvdata(pmu->dev, pmu);
9071 pmu->dev->bus = &pmu_bus;
9072 pmu->dev->release = pmu_dev_release;
9073 ret = device_add(pmu->dev);
9077 /* For PMUs with address filters, throw in an extra attribute: */
9078 if (pmu->nr_addr_filters)
9079 ret = device_create_file(pmu->dev, &dev_attr_nr_addr_filters);
9088 device_del(pmu->dev);
9091 put_device(pmu->dev);
9095 static struct lock_class_key cpuctx_mutex;
9096 static struct lock_class_key cpuctx_lock;
9098 int perf_pmu_register(struct pmu *pmu, const char *name, int type)
9102 mutex_lock(&pmus_lock);
9104 pmu->pmu_disable_count = alloc_percpu(int);
9105 if (!pmu->pmu_disable_count)
9114 type = idr_alloc(&pmu_idr, pmu, PERF_TYPE_MAX, 0, GFP_KERNEL);
9122 if (pmu_bus_running) {
9123 ret = pmu_dev_alloc(pmu);
9129 if (pmu->task_ctx_nr == perf_hw_context) {
9130 static int hw_context_taken = 0;
9133 * Other than systems with heterogeneous CPUs, it never makes
9134 * sense for two PMUs to share perf_hw_context. PMUs which are
9135 * uncore must use perf_invalid_context.
9137 if (WARN_ON_ONCE(hw_context_taken &&
9138 !(pmu->capabilities & PERF_PMU_CAP_HETEROGENEOUS_CPUS)))
9139 pmu->task_ctx_nr = perf_invalid_context;
9141 hw_context_taken = 1;
9144 pmu->pmu_cpu_context = find_pmu_context(pmu->task_ctx_nr);
9145 if (pmu->pmu_cpu_context)
9146 goto got_cpu_context;
9149 pmu->pmu_cpu_context = alloc_percpu(struct perf_cpu_context);
9150 if (!pmu->pmu_cpu_context)
9153 for_each_possible_cpu(cpu) {
9154 struct perf_cpu_context *cpuctx;
9156 cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
9157 __perf_event_init_context(&cpuctx->ctx);
9158 lockdep_set_class(&cpuctx->ctx.mutex, &cpuctx_mutex);
9159 lockdep_set_class(&cpuctx->ctx.lock, &cpuctx_lock);
9160 cpuctx->ctx.pmu = pmu;
9161 cpuctx->online = cpumask_test_cpu(cpu, perf_online_mask);
9163 __perf_mux_hrtimer_init(cpuctx, cpu);
9167 if (!pmu->start_txn) {
9168 if (pmu->pmu_enable) {
9170 * If we have pmu_enable/pmu_disable calls, install
9171 * transaction stubs that use that to try and batch
9172 * hardware accesses.
9174 pmu->start_txn = perf_pmu_start_txn;
9175 pmu->commit_txn = perf_pmu_commit_txn;
9176 pmu->cancel_txn = perf_pmu_cancel_txn;
9178 pmu->start_txn = perf_pmu_nop_txn;
9179 pmu->commit_txn = perf_pmu_nop_int;
9180 pmu->cancel_txn = perf_pmu_nop_void;
9184 if (!pmu->pmu_enable) {
9185 pmu->pmu_enable = perf_pmu_nop_void;
9186 pmu->pmu_disable = perf_pmu_nop_void;
9189 if (!pmu->event_idx)
9190 pmu->event_idx = perf_event_idx_default;
9192 list_add_rcu(&pmu->entry, &pmus);
9193 atomic_set(&pmu->exclusive_cnt, 0);
9196 mutex_unlock(&pmus_lock);
9201 device_del(pmu->dev);
9202 put_device(pmu->dev);
9205 if (pmu->type >= PERF_TYPE_MAX)
9206 idr_remove(&pmu_idr, pmu->type);
9209 free_percpu(pmu->pmu_disable_count);
9212 EXPORT_SYMBOL_GPL(perf_pmu_register);
9214 void perf_pmu_unregister(struct pmu *pmu)
9218 mutex_lock(&pmus_lock);
9219 remove_device = pmu_bus_running;
9220 list_del_rcu(&pmu->entry);
9221 mutex_unlock(&pmus_lock);
9224 * We dereference the pmu list under both SRCU and regular RCU, so
9225 * synchronize against both of those.
9227 synchronize_srcu(&pmus_srcu);
9230 free_percpu(pmu->pmu_disable_count);
9231 if (pmu->type >= PERF_TYPE_MAX)
9232 idr_remove(&pmu_idr, pmu->type);
9233 if (remove_device) {
9234 if (pmu->nr_addr_filters)
9235 device_remove_file(pmu->dev, &dev_attr_nr_addr_filters);
9236 device_del(pmu->dev);
9237 put_device(pmu->dev);
9239 free_pmu_context(pmu);
9241 EXPORT_SYMBOL_GPL(perf_pmu_unregister);
9243 static int perf_try_init_event(struct pmu *pmu, struct perf_event *event)
9245 struct perf_event_context *ctx = NULL;
9248 if (!try_module_get(pmu->module))
9251 if (event->group_leader != event) {
9253 * This ctx->mutex can nest when we're called through
9254 * inheritance. See the perf_event_ctx_lock_nested() comment.
9256 ctx = perf_event_ctx_lock_nested(event->group_leader,
9257 SINGLE_DEPTH_NESTING);
9262 ret = pmu->event_init(event);
9265 perf_event_ctx_unlock(event->group_leader, ctx);
9268 module_put(pmu->module);
9273 static struct pmu *perf_init_event(struct perf_event *event)
9279 idx = srcu_read_lock(&pmus_srcu);
9281 /* Try parent's PMU first: */
9282 if (event->parent && event->parent->pmu) {
9283 pmu = event->parent->pmu;
9284 ret = perf_try_init_event(pmu, event);
9290 pmu = idr_find(&pmu_idr, event->attr.type);
9293 ret = perf_try_init_event(pmu, event);
9299 list_for_each_entry_rcu(pmu, &pmus, entry) {
9300 ret = perf_try_init_event(pmu, event);
9304 if (ret != -ENOENT) {
9309 pmu = ERR_PTR(-ENOENT);
9311 srcu_read_unlock(&pmus_srcu, idx);
9316 static void attach_sb_event(struct perf_event *event)
9318 struct pmu_event_list *pel = per_cpu_ptr(&pmu_sb_events, event->cpu);
9320 raw_spin_lock(&pel->lock);
9321 list_add_rcu(&event->sb_list, &pel->list);
9322 raw_spin_unlock(&pel->lock);
9326 * We keep a list of all !task (and therefore per-cpu) events
9327 * that need to receive side-band records.
9329 * This avoids having to scan all the various PMU per-cpu contexts
9332 static void account_pmu_sb_event(struct perf_event *event)
9334 if (is_sb_event(event))
9335 attach_sb_event(event);
9338 static void account_event_cpu(struct perf_event *event, int cpu)
9343 if (is_cgroup_event(event))
9344 atomic_inc(&per_cpu(perf_cgroup_events, cpu));
9347 /* Freq events need the tick to stay alive (see perf_event_task_tick). */
9348 static void account_freq_event_nohz(void)
9350 #ifdef CONFIG_NO_HZ_FULL
9351 /* Lock so we don't race with concurrent unaccount */
9352 spin_lock(&nr_freq_lock);
9353 if (atomic_inc_return(&nr_freq_events) == 1)
9354 tick_nohz_dep_set(TICK_DEP_BIT_PERF_EVENTS);
9355 spin_unlock(&nr_freq_lock);
9359 static void account_freq_event(void)
9361 if (tick_nohz_full_enabled())
9362 account_freq_event_nohz();
9364 atomic_inc(&nr_freq_events);
9368 static void account_event(struct perf_event *event)
9375 if (event->attach_state & PERF_ATTACH_TASK)
9377 if (event->attr.mmap || event->attr.mmap_data)
9378 atomic_inc(&nr_mmap_events);
9379 if (event->attr.comm)
9380 atomic_inc(&nr_comm_events);
9381 if (event->attr.namespaces)
9382 atomic_inc(&nr_namespaces_events);
9383 if (event->attr.task)
9384 atomic_inc(&nr_task_events);
9385 if (event->attr.freq)
9386 account_freq_event();
9387 if (event->attr.context_switch) {
9388 atomic_inc(&nr_switch_events);
9391 if (has_branch_stack(event))
9393 if (is_cgroup_event(event))
9397 if (atomic_inc_not_zero(&perf_sched_count))
9400 mutex_lock(&perf_sched_mutex);
9401 if (!atomic_read(&perf_sched_count)) {
9402 static_branch_enable(&perf_sched_events);
9404 * Guarantee that all CPUs observe they key change and
9405 * call the perf scheduling hooks before proceeding to
9406 * install events that need them.
9408 synchronize_sched();
9411 * Now that we have waited for the sync_sched(), allow further
9412 * increments to by-pass the mutex.
9414 atomic_inc(&perf_sched_count);
9415 mutex_unlock(&perf_sched_mutex);
9419 account_event_cpu(event, event->cpu);
9421 account_pmu_sb_event(event);
9425 * Allocate and initialize a event structure
9427 static struct perf_event *
9428 perf_event_alloc(struct perf_event_attr *attr, int cpu,
9429 struct task_struct *task,
9430 struct perf_event *group_leader,
9431 struct perf_event *parent_event,
9432 perf_overflow_handler_t overflow_handler,
9433 void *context, int cgroup_fd)
9436 struct perf_event *event;
9437 struct hw_perf_event *hwc;
9440 if ((unsigned)cpu >= nr_cpu_ids) {
9441 if (!task || cpu != -1)
9442 return ERR_PTR(-EINVAL);
9445 event = kzalloc(sizeof(*event), GFP_KERNEL);
9447 return ERR_PTR(-ENOMEM);
9450 * Single events are their own group leaders, with an
9451 * empty sibling list:
9454 group_leader = event;
9456 mutex_init(&event->child_mutex);
9457 INIT_LIST_HEAD(&event->child_list);
9459 INIT_LIST_HEAD(&event->group_entry);
9460 INIT_LIST_HEAD(&event->event_entry);
9461 INIT_LIST_HEAD(&event->sibling_list);
9462 INIT_LIST_HEAD(&event->rb_entry);
9463 INIT_LIST_HEAD(&event->active_entry);
9464 INIT_LIST_HEAD(&event->addr_filters.list);
9465 INIT_HLIST_NODE(&event->hlist_entry);
9468 init_waitqueue_head(&event->waitq);
9469 init_irq_work(&event->pending, perf_pending_event);
9471 mutex_init(&event->mmap_mutex);
9472 raw_spin_lock_init(&event->addr_filters.lock);
9474 atomic_long_set(&event->refcount, 1);
9476 event->attr = *attr;
9477 event->group_leader = group_leader;
9481 event->parent = parent_event;
9483 event->ns = get_pid_ns(task_active_pid_ns(current));
9484 event->id = atomic64_inc_return(&perf_event_id);
9486 event->state = PERF_EVENT_STATE_INACTIVE;
9489 event->attach_state = PERF_ATTACH_TASK;
9491 * XXX pmu::event_init needs to know what task to account to
9492 * and we cannot use the ctx information because we need the
9493 * pmu before we get a ctx.
9495 event->hw.target = task;
9498 event->clock = &local_clock;
9500 event->clock = parent_event->clock;
9502 if (!overflow_handler && parent_event) {
9503 overflow_handler = parent_event->overflow_handler;
9504 context = parent_event->overflow_handler_context;
9505 #if defined(CONFIG_BPF_SYSCALL) && defined(CONFIG_EVENT_TRACING)
9506 if (overflow_handler == bpf_overflow_handler) {
9507 struct bpf_prog *prog = bpf_prog_inc(parent_event->prog);
9510 err = PTR_ERR(prog);
9514 event->orig_overflow_handler =
9515 parent_event->orig_overflow_handler;
9520 if (overflow_handler) {
9521 event->overflow_handler = overflow_handler;
9522 event->overflow_handler_context = context;
9523 } else if (is_write_backward(event)){
9524 event->overflow_handler = perf_event_output_backward;
9525 event->overflow_handler_context = NULL;
9527 event->overflow_handler = perf_event_output_forward;
9528 event->overflow_handler_context = NULL;
9531 perf_event__state_init(event);
9536 hwc->sample_period = attr->sample_period;
9537 if (attr->freq && attr->sample_freq)
9538 hwc->sample_period = 1;
9539 hwc->last_period = hwc->sample_period;
9541 local64_set(&hwc->period_left, hwc->sample_period);
9544 * We currently do not support PERF_SAMPLE_READ on inherited events.
9545 * See perf_output_read().
9547 if (attr->inherit && (attr->sample_type & PERF_SAMPLE_READ))
9550 if (!has_branch_stack(event))
9551 event->attr.branch_sample_type = 0;
9553 if (cgroup_fd != -1) {
9554 err = perf_cgroup_connect(cgroup_fd, event, attr, group_leader);
9559 pmu = perf_init_event(event);
9565 err = exclusive_event_init(event);
9569 if (has_addr_filter(event)) {
9570 event->addr_filters_offs = kcalloc(pmu->nr_addr_filters,
9571 sizeof(unsigned long),
9573 if (!event->addr_filters_offs) {
9578 /* force hw sync on the address filters */
9579 event->addr_filters_gen = 1;
9582 if (!event->parent) {
9583 if (event->attr.sample_type & PERF_SAMPLE_CALLCHAIN) {
9584 err = get_callchain_buffers(attr->sample_max_stack);
9586 goto err_addr_filters;
9590 /* symmetric to unaccount_event() in _free_event() */
9591 account_event(event);
9596 kfree(event->addr_filters_offs);
9599 exclusive_event_destroy(event);
9603 event->destroy(event);
9604 module_put(pmu->module);
9606 if (is_cgroup_event(event))
9607 perf_detach_cgroup(event);
9609 put_pid_ns(event->ns);
9612 return ERR_PTR(err);
9615 static int perf_copy_attr(struct perf_event_attr __user *uattr,
9616 struct perf_event_attr *attr)
9621 if (!access_ok(VERIFY_WRITE, uattr, PERF_ATTR_SIZE_VER0))
9625 * zero the full structure, so that a short copy will be nice.
9627 memset(attr, 0, sizeof(*attr));
9629 ret = get_user(size, &uattr->size);
9633 if (size > PAGE_SIZE) /* silly large */
9636 if (!size) /* abi compat */
9637 size = PERF_ATTR_SIZE_VER0;
9639 if (size < PERF_ATTR_SIZE_VER0)
9643 * If we're handed a bigger struct than we know of,
9644 * ensure all the unknown bits are 0 - i.e. new
9645 * user-space does not rely on any kernel feature
9646 * extensions we dont know about yet.
9648 if (size > sizeof(*attr)) {
9649 unsigned char __user *addr;
9650 unsigned char __user *end;
9653 addr = (void __user *)uattr + sizeof(*attr);
9654 end = (void __user *)uattr + size;
9656 for (; addr < end; addr++) {
9657 ret = get_user(val, addr);
9663 size = sizeof(*attr);
9666 ret = copy_from_user(attr, uattr, size);
9672 if (attr->__reserved_1)
9675 if (attr->sample_type & ~(PERF_SAMPLE_MAX-1))
9678 if (attr->read_format & ~(PERF_FORMAT_MAX-1))
9681 if (attr->sample_type & PERF_SAMPLE_BRANCH_STACK) {
9682 u64 mask = attr->branch_sample_type;
9684 /* only using defined bits */
9685 if (mask & ~(PERF_SAMPLE_BRANCH_MAX-1))
9688 /* at least one branch bit must be set */
9689 if (!(mask & ~PERF_SAMPLE_BRANCH_PLM_ALL))
9692 /* propagate priv level, when not set for branch */
9693 if (!(mask & PERF_SAMPLE_BRANCH_PLM_ALL)) {
9695 /* exclude_kernel checked on syscall entry */
9696 if (!attr->exclude_kernel)
9697 mask |= PERF_SAMPLE_BRANCH_KERNEL;
9699 if (!attr->exclude_user)
9700 mask |= PERF_SAMPLE_BRANCH_USER;
9702 if (!attr->exclude_hv)
9703 mask |= PERF_SAMPLE_BRANCH_HV;
9705 * adjust user setting (for HW filter setup)
9707 attr->branch_sample_type = mask;
9709 /* privileged levels capture (kernel, hv): check permissions */
9710 if ((mask & PERF_SAMPLE_BRANCH_PERM_PLM)
9711 && perf_paranoid_kernel() && !capable(CAP_SYS_ADMIN))
9715 if (attr->sample_type & PERF_SAMPLE_REGS_USER) {
9716 ret = perf_reg_validate(attr->sample_regs_user);
9721 if (attr->sample_type & PERF_SAMPLE_STACK_USER) {
9722 if (!arch_perf_have_user_stack_dump())
9726 * We have __u32 type for the size, but so far
9727 * we can only use __u16 as maximum due to the
9728 * __u16 sample size limit.
9730 if (attr->sample_stack_user >= USHRT_MAX)
9732 else if (!IS_ALIGNED(attr->sample_stack_user, sizeof(u64)))
9736 if (attr->sample_type & PERF_SAMPLE_REGS_INTR)
9737 ret = perf_reg_validate(attr->sample_regs_intr);
9742 put_user(sizeof(*attr), &uattr->size);
9748 perf_event_set_output(struct perf_event *event, struct perf_event *output_event)
9750 struct ring_buffer *rb = NULL;
9756 /* don't allow circular references */
9757 if (event == output_event)
9761 * Don't allow cross-cpu buffers
9763 if (output_event->cpu != event->cpu)
9767 * If its not a per-cpu rb, it must be the same task.
9769 if (output_event->cpu == -1 && output_event->ctx != event->ctx)
9773 * Mixing clocks in the same buffer is trouble you don't need.
9775 if (output_event->clock != event->clock)
9779 * Either writing ring buffer from beginning or from end.
9780 * Mixing is not allowed.
9782 if (is_write_backward(output_event) != is_write_backward(event))
9786 * If both events generate aux data, they must be on the same PMU
9788 if (has_aux(event) && has_aux(output_event) &&
9789 event->pmu != output_event->pmu)
9793 mutex_lock(&event->mmap_mutex);
9794 /* Can't redirect output if we've got an active mmap() */
9795 if (atomic_read(&event->mmap_count))
9799 /* get the rb we want to redirect to */
9800 rb = ring_buffer_get(output_event);
9805 ring_buffer_attach(event, rb);
9809 mutex_unlock(&event->mmap_mutex);
9815 static void mutex_lock_double(struct mutex *a, struct mutex *b)
9821 mutex_lock_nested(b, SINGLE_DEPTH_NESTING);
9824 static int perf_event_set_clock(struct perf_event *event, clockid_t clk_id)
9826 bool nmi_safe = false;
9829 case CLOCK_MONOTONIC:
9830 event->clock = &ktime_get_mono_fast_ns;
9834 case CLOCK_MONOTONIC_RAW:
9835 event->clock = &ktime_get_raw_fast_ns;
9839 case CLOCK_REALTIME:
9840 event->clock = &ktime_get_real_ns;
9843 case CLOCK_BOOTTIME:
9844 event->clock = &ktime_get_boot_ns;
9848 event->clock = &ktime_get_tai_ns;
9855 if (!nmi_safe && !(event->pmu->capabilities & PERF_PMU_CAP_NO_NMI))
9862 * Variation on perf_event_ctx_lock_nested(), except we take two context
9865 static struct perf_event_context *
9866 __perf_event_ctx_lock_double(struct perf_event *group_leader,
9867 struct perf_event_context *ctx)
9869 struct perf_event_context *gctx;
9873 gctx = READ_ONCE(group_leader->ctx);
9874 if (!atomic_inc_not_zero(&gctx->refcount)) {
9880 mutex_lock_double(&gctx->mutex, &ctx->mutex);
9882 if (group_leader->ctx != gctx) {
9883 mutex_unlock(&ctx->mutex);
9884 mutex_unlock(&gctx->mutex);
9893 * sys_perf_event_open - open a performance event, associate it to a task/cpu
9895 * @attr_uptr: event_id type attributes for monitoring/sampling
9898 * @group_fd: group leader event fd
9900 SYSCALL_DEFINE5(perf_event_open,
9901 struct perf_event_attr __user *, attr_uptr,
9902 pid_t, pid, int, cpu, int, group_fd, unsigned long, flags)
9904 struct perf_event *group_leader = NULL, *output_event = NULL;
9905 struct perf_event *event, *sibling;
9906 struct perf_event_attr attr;
9907 struct perf_event_context *ctx, *uninitialized_var(gctx);
9908 struct file *event_file = NULL;
9909 struct fd group = {NULL, 0};
9910 struct task_struct *task = NULL;
9915 int f_flags = O_RDWR;
9918 /* for future expandability... */
9919 if (flags & ~PERF_FLAG_ALL)
9922 err = perf_copy_attr(attr_uptr, &attr);
9926 if (!attr.exclude_kernel) {
9927 if (perf_paranoid_kernel() && !capable(CAP_SYS_ADMIN))
9931 if (attr.namespaces) {
9932 if (!capable(CAP_SYS_ADMIN))
9937 if (attr.sample_freq > sysctl_perf_event_sample_rate)
9940 if (attr.sample_period & (1ULL << 63))
9944 /* Only privileged users can get physical addresses */
9945 if ((attr.sample_type & PERF_SAMPLE_PHYS_ADDR) &&
9946 perf_paranoid_kernel() && !capable(CAP_SYS_ADMIN))
9949 if (!attr.sample_max_stack)
9950 attr.sample_max_stack = sysctl_perf_event_max_stack;
9953 * In cgroup mode, the pid argument is used to pass the fd
9954 * opened to the cgroup directory in cgroupfs. The cpu argument
9955 * designates the cpu on which to monitor threads from that
9958 if ((flags & PERF_FLAG_PID_CGROUP) && (pid == -1 || cpu == -1))
9961 if (flags & PERF_FLAG_FD_CLOEXEC)
9962 f_flags |= O_CLOEXEC;
9964 event_fd = get_unused_fd_flags(f_flags);
9968 if (group_fd != -1) {
9969 err = perf_fget_light(group_fd, &group);
9972 group_leader = group.file->private_data;
9973 if (flags & PERF_FLAG_FD_OUTPUT)
9974 output_event = group_leader;
9975 if (flags & PERF_FLAG_FD_NO_GROUP)
9976 group_leader = NULL;
9979 if (pid != -1 && !(flags & PERF_FLAG_PID_CGROUP)) {
9980 task = find_lively_task_by_vpid(pid);
9982 err = PTR_ERR(task);
9987 if (task && group_leader &&
9988 group_leader->attr.inherit != attr.inherit) {
9994 err = mutex_lock_interruptible(&task->signal->cred_guard_mutex);
9999 * Reuse ptrace permission checks for now.
10001 * We must hold cred_guard_mutex across this and any potential
10002 * perf_install_in_context() call for this new event to
10003 * serialize against exec() altering our credentials (and the
10004 * perf_event_exit_task() that could imply).
10007 if (!ptrace_may_access(task, PTRACE_MODE_READ_REALCREDS))
10011 if (flags & PERF_FLAG_PID_CGROUP)
10014 event = perf_event_alloc(&attr, cpu, task, group_leader, NULL,
10015 NULL, NULL, cgroup_fd);
10016 if (IS_ERR(event)) {
10017 err = PTR_ERR(event);
10021 if (is_sampling_event(event)) {
10022 if (event->pmu->capabilities & PERF_PMU_CAP_NO_INTERRUPT) {
10029 * Special case software events and allow them to be part of
10030 * any hardware group.
10034 if (attr.use_clockid) {
10035 err = perf_event_set_clock(event, attr.clockid);
10040 if (pmu->task_ctx_nr == perf_sw_context)
10041 event->event_caps |= PERF_EV_CAP_SOFTWARE;
10043 if (group_leader &&
10044 (is_software_event(event) != is_software_event(group_leader))) {
10045 if (is_software_event(event)) {
10047 * If event and group_leader are not both a software
10048 * event, and event is, then group leader is not.
10050 * Allow the addition of software events to !software
10051 * groups, this is safe because software events never
10052 * fail to schedule.
10054 pmu = group_leader->pmu;
10055 } else if (is_software_event(group_leader) &&
10056 (group_leader->group_caps & PERF_EV_CAP_SOFTWARE)) {
10058 * In case the group is a pure software group, and we
10059 * try to add a hardware event, move the whole group to
10060 * the hardware context.
10067 * Get the target context (task or percpu):
10069 ctx = find_get_context(pmu, task, event);
10071 err = PTR_ERR(ctx);
10075 if ((pmu->capabilities & PERF_PMU_CAP_EXCLUSIVE) && group_leader) {
10081 * Look up the group leader (we will attach this event to it):
10083 if (group_leader) {
10087 * Do not allow a recursive hierarchy (this new sibling
10088 * becoming part of another group-sibling):
10090 if (group_leader->group_leader != group_leader)
10093 /* All events in a group should have the same clock */
10094 if (group_leader->clock != event->clock)
10098 * Make sure we're both events for the same CPU;
10099 * grouping events for different CPUs is broken; since
10100 * you can never concurrently schedule them anyhow.
10102 if (group_leader->cpu != event->cpu)
10106 * Make sure we're both on the same task, or both
10109 if (group_leader->ctx->task != ctx->task)
10113 * Do not allow to attach to a group in a different task
10114 * or CPU context. If we're moving SW events, we'll fix
10115 * this up later, so allow that.
10117 if (!move_group && group_leader->ctx != ctx)
10121 * Only a group leader can be exclusive or pinned
10123 if (attr.exclusive || attr.pinned)
10127 if (output_event) {
10128 err = perf_event_set_output(event, output_event);
10133 event_file = anon_inode_getfile("[perf_event]", &perf_fops, event,
10135 if (IS_ERR(event_file)) {
10136 err = PTR_ERR(event_file);
10142 gctx = __perf_event_ctx_lock_double(group_leader, ctx);
10144 if (gctx->task == TASK_TOMBSTONE) {
10150 * Check if we raced against another sys_perf_event_open() call
10151 * moving the software group underneath us.
10153 if (!(group_leader->group_caps & PERF_EV_CAP_SOFTWARE)) {
10155 * If someone moved the group out from under us, check
10156 * if this new event wound up on the same ctx, if so
10157 * its the regular !move_group case, otherwise fail.
10163 perf_event_ctx_unlock(group_leader, gctx);
10168 mutex_lock(&ctx->mutex);
10171 if (ctx->task == TASK_TOMBSTONE) {
10176 if (!perf_event_validate_size(event)) {
10183 * Check if the @cpu we're creating an event for is online.
10185 * We use the perf_cpu_context::ctx::mutex to serialize against
10186 * the hotplug notifiers. See perf_event_{init,exit}_cpu().
10188 struct perf_cpu_context *cpuctx =
10189 container_of(ctx, struct perf_cpu_context, ctx);
10191 if (!cpuctx->online) {
10199 * Must be under the same ctx::mutex as perf_install_in_context(),
10200 * because we need to serialize with concurrent event creation.
10202 if (!exclusive_event_installable(event, ctx)) {
10203 /* exclusive and group stuff are assumed mutually exclusive */
10204 WARN_ON_ONCE(move_group);
10210 WARN_ON_ONCE(ctx->parent_ctx);
10213 * This is the point on no return; we cannot fail hereafter. This is
10214 * where we start modifying current state.
10219 * See perf_event_ctx_lock() for comments on the details
10220 * of swizzling perf_event::ctx.
10222 perf_remove_from_context(group_leader, 0);
10225 list_for_each_entry(sibling, &group_leader->sibling_list,
10227 perf_remove_from_context(sibling, 0);
10232 * Wait for everybody to stop referencing the events through
10233 * the old lists, before installing it on new lists.
10238 * Install the group siblings before the group leader.
10240 * Because a group leader will try and install the entire group
10241 * (through the sibling list, which is still in-tact), we can
10242 * end up with siblings installed in the wrong context.
10244 * By installing siblings first we NO-OP because they're not
10245 * reachable through the group lists.
10247 list_for_each_entry(sibling, &group_leader->sibling_list,
10249 perf_event__state_init(sibling);
10250 perf_install_in_context(ctx, sibling, sibling->cpu);
10255 * Removing from the context ends up with disabled
10256 * event. What we want here is event in the initial
10257 * startup state, ready to be add into new context.
10259 perf_event__state_init(group_leader);
10260 perf_install_in_context(ctx, group_leader, group_leader->cpu);
10265 * Precalculate sample_data sizes; do while holding ctx::mutex such
10266 * that we're serialized against further additions and before
10267 * perf_install_in_context() which is the point the event is active and
10268 * can use these values.
10270 perf_event__header_size(event);
10271 perf_event__id_header_size(event);
10273 event->owner = current;
10275 perf_install_in_context(ctx, event, event->cpu);
10276 perf_unpin_context(ctx);
10279 perf_event_ctx_unlock(group_leader, gctx);
10280 mutex_unlock(&ctx->mutex);
10283 mutex_unlock(&task->signal->cred_guard_mutex);
10284 put_task_struct(task);
10287 mutex_lock(¤t->perf_event_mutex);
10288 list_add_tail(&event->owner_entry, ¤t->perf_event_list);
10289 mutex_unlock(¤t->perf_event_mutex);
10292 * Drop the reference on the group_event after placing the
10293 * new event on the sibling_list. This ensures destruction
10294 * of the group leader will find the pointer to itself in
10295 * perf_group_detach().
10298 fd_install(event_fd, event_file);
10303 perf_event_ctx_unlock(group_leader, gctx);
10304 mutex_unlock(&ctx->mutex);
10308 perf_unpin_context(ctx);
10312 * If event_file is set, the fput() above will have called ->release()
10313 * and that will take care of freeing the event.
10319 mutex_unlock(&task->signal->cred_guard_mutex);
10322 put_task_struct(task);
10326 put_unused_fd(event_fd);
10331 * perf_event_create_kernel_counter
10333 * @attr: attributes of the counter to create
10334 * @cpu: cpu in which the counter is bound
10335 * @task: task to profile (NULL for percpu)
10337 struct perf_event *
10338 perf_event_create_kernel_counter(struct perf_event_attr *attr, int cpu,
10339 struct task_struct *task,
10340 perf_overflow_handler_t overflow_handler,
10343 struct perf_event_context *ctx;
10344 struct perf_event *event;
10348 * Get the target context (task or percpu):
10351 event = perf_event_alloc(attr, cpu, task, NULL, NULL,
10352 overflow_handler, context, -1);
10353 if (IS_ERR(event)) {
10354 err = PTR_ERR(event);
10358 /* Mark owner so we could distinguish it from user events. */
10359 event->owner = TASK_TOMBSTONE;
10361 ctx = find_get_context(event->pmu, task, event);
10363 err = PTR_ERR(ctx);
10367 WARN_ON_ONCE(ctx->parent_ctx);
10368 mutex_lock(&ctx->mutex);
10369 if (ctx->task == TASK_TOMBSTONE) {
10376 * Check if the @cpu we're creating an event for is online.
10378 * We use the perf_cpu_context::ctx::mutex to serialize against
10379 * the hotplug notifiers. See perf_event_{init,exit}_cpu().
10381 struct perf_cpu_context *cpuctx =
10382 container_of(ctx, struct perf_cpu_context, ctx);
10383 if (!cpuctx->online) {
10389 if (!exclusive_event_installable(event, ctx)) {
10394 perf_install_in_context(ctx, event, cpu);
10395 perf_unpin_context(ctx);
10396 mutex_unlock(&ctx->mutex);
10401 mutex_unlock(&ctx->mutex);
10402 perf_unpin_context(ctx);
10407 return ERR_PTR(err);
10409 EXPORT_SYMBOL_GPL(perf_event_create_kernel_counter);
10411 void perf_pmu_migrate_context(struct pmu *pmu, int src_cpu, int dst_cpu)
10413 struct perf_event_context *src_ctx;
10414 struct perf_event_context *dst_ctx;
10415 struct perf_event *event, *tmp;
10418 src_ctx = &per_cpu_ptr(pmu->pmu_cpu_context, src_cpu)->ctx;
10419 dst_ctx = &per_cpu_ptr(pmu->pmu_cpu_context, dst_cpu)->ctx;
10422 * See perf_event_ctx_lock() for comments on the details
10423 * of swizzling perf_event::ctx.
10425 mutex_lock_double(&src_ctx->mutex, &dst_ctx->mutex);
10426 list_for_each_entry_safe(event, tmp, &src_ctx->event_list,
10428 perf_remove_from_context(event, 0);
10429 unaccount_event_cpu(event, src_cpu);
10431 list_add(&event->migrate_entry, &events);
10435 * Wait for the events to quiesce before re-instating them.
10440 * Re-instate events in 2 passes.
10442 * Skip over group leaders and only install siblings on this first
10443 * pass, siblings will not get enabled without a leader, however a
10444 * leader will enable its siblings, even if those are still on the old
10447 list_for_each_entry_safe(event, tmp, &events, migrate_entry) {
10448 if (event->group_leader == event)
10451 list_del(&event->migrate_entry);
10452 if (event->state >= PERF_EVENT_STATE_OFF)
10453 event->state = PERF_EVENT_STATE_INACTIVE;
10454 account_event_cpu(event, dst_cpu);
10455 perf_install_in_context(dst_ctx, event, dst_cpu);
10460 * Once all the siblings are setup properly, install the group leaders
10463 list_for_each_entry_safe(event, tmp, &events, migrate_entry) {
10464 list_del(&event->migrate_entry);
10465 if (event->state >= PERF_EVENT_STATE_OFF)
10466 event->state = PERF_EVENT_STATE_INACTIVE;
10467 account_event_cpu(event, dst_cpu);
10468 perf_install_in_context(dst_ctx, event, dst_cpu);
10471 mutex_unlock(&dst_ctx->mutex);
10472 mutex_unlock(&src_ctx->mutex);
10474 EXPORT_SYMBOL_GPL(perf_pmu_migrate_context);
10476 static void sync_child_event(struct perf_event *child_event,
10477 struct task_struct *child)
10479 struct perf_event *parent_event = child_event->parent;
10482 if (child_event->attr.inherit_stat)
10483 perf_event_read_event(child_event, child);
10485 child_val = perf_event_count(child_event);
10488 * Add back the child's count to the parent's count:
10490 atomic64_add(child_val, &parent_event->child_count);
10491 atomic64_add(child_event->total_time_enabled,
10492 &parent_event->child_total_time_enabled);
10493 atomic64_add(child_event->total_time_running,
10494 &parent_event->child_total_time_running);
10498 perf_event_exit_event(struct perf_event *child_event,
10499 struct perf_event_context *child_ctx,
10500 struct task_struct *child)
10502 struct perf_event *parent_event = child_event->parent;
10505 * Do not destroy the 'original' grouping; because of the context
10506 * switch optimization the original events could've ended up in a
10507 * random child task.
10509 * If we were to destroy the original group, all group related
10510 * operations would cease to function properly after this random
10513 * Do destroy all inherited groups, we don't care about those
10514 * and being thorough is better.
10516 raw_spin_lock_irq(&child_ctx->lock);
10517 WARN_ON_ONCE(child_ctx->is_active);
10520 perf_group_detach(child_event);
10521 list_del_event(child_event, child_ctx);
10522 child_event->state = PERF_EVENT_STATE_EXIT; /* is_event_hup() */
10523 raw_spin_unlock_irq(&child_ctx->lock);
10526 * Parent events are governed by their filedesc, retain them.
10528 if (!parent_event) {
10529 perf_event_wakeup(child_event);
10533 * Child events can be cleaned up.
10536 sync_child_event(child_event, child);
10539 * Remove this event from the parent's list
10541 WARN_ON_ONCE(parent_event->ctx->parent_ctx);
10542 mutex_lock(&parent_event->child_mutex);
10543 list_del_init(&child_event->child_list);
10544 mutex_unlock(&parent_event->child_mutex);
10547 * Kick perf_poll() for is_event_hup().
10549 perf_event_wakeup(parent_event);
10550 free_event(child_event);
10551 put_event(parent_event);
10554 static void perf_event_exit_task_context(struct task_struct *child, int ctxn)
10556 struct perf_event_context *child_ctx, *clone_ctx = NULL;
10557 struct perf_event *child_event, *next;
10559 WARN_ON_ONCE(child != current);
10561 child_ctx = perf_pin_task_context(child, ctxn);
10566 * In order to reduce the amount of tricky in ctx tear-down, we hold
10567 * ctx::mutex over the entire thing. This serializes against almost
10568 * everything that wants to access the ctx.
10570 * The exception is sys_perf_event_open() /
10571 * perf_event_create_kernel_count() which does find_get_context()
10572 * without ctx::mutex (it cannot because of the move_group double mutex
10573 * lock thing). See the comments in perf_install_in_context().
10575 mutex_lock(&child_ctx->mutex);
10578 * In a single ctx::lock section, de-schedule the events and detach the
10579 * context from the task such that we cannot ever get it scheduled back
10582 raw_spin_lock_irq(&child_ctx->lock);
10583 task_ctx_sched_out(__get_cpu_context(child_ctx), child_ctx, EVENT_ALL);
10586 * Now that the context is inactive, destroy the task <-> ctx relation
10587 * and mark the context dead.
10589 RCU_INIT_POINTER(child->perf_event_ctxp[ctxn], NULL);
10590 put_ctx(child_ctx); /* cannot be last */
10591 WRITE_ONCE(child_ctx->task, TASK_TOMBSTONE);
10592 put_task_struct(current); /* cannot be last */
10594 clone_ctx = unclone_ctx(child_ctx);
10595 raw_spin_unlock_irq(&child_ctx->lock);
10598 put_ctx(clone_ctx);
10601 * Report the task dead after unscheduling the events so that we
10602 * won't get any samples after PERF_RECORD_EXIT. We can however still
10603 * get a few PERF_RECORD_READ events.
10605 perf_event_task(child, child_ctx, 0);
10607 list_for_each_entry_safe(child_event, next, &child_ctx->event_list, event_entry)
10608 perf_event_exit_event(child_event, child_ctx, child);
10610 mutex_unlock(&child_ctx->mutex);
10612 put_ctx(child_ctx);
10616 * When a child task exits, feed back event values to parent events.
10618 * Can be called with cred_guard_mutex held when called from
10619 * install_exec_creds().
10621 void perf_event_exit_task(struct task_struct *child)
10623 struct perf_event *event, *tmp;
10626 mutex_lock(&child->perf_event_mutex);
10627 list_for_each_entry_safe(event, tmp, &child->perf_event_list,
10629 list_del_init(&event->owner_entry);
10632 * Ensure the list deletion is visible before we clear
10633 * the owner, closes a race against perf_release() where
10634 * we need to serialize on the owner->perf_event_mutex.
10636 smp_store_release(&event->owner, NULL);
10638 mutex_unlock(&child->perf_event_mutex);
10640 for_each_task_context_nr(ctxn)
10641 perf_event_exit_task_context(child, ctxn);
10644 * The perf_event_exit_task_context calls perf_event_task
10645 * with child's task_ctx, which generates EXIT events for
10646 * child contexts and sets child->perf_event_ctxp[] to NULL.
10647 * At this point we need to send EXIT events to cpu contexts.
10649 perf_event_task(child, NULL, 0);
10652 static void perf_free_event(struct perf_event *event,
10653 struct perf_event_context *ctx)
10655 struct perf_event *parent = event->parent;
10657 if (WARN_ON_ONCE(!parent))
10660 mutex_lock(&parent->child_mutex);
10661 list_del_init(&event->child_list);
10662 mutex_unlock(&parent->child_mutex);
10666 raw_spin_lock_irq(&ctx->lock);
10667 perf_group_detach(event);
10668 list_del_event(event, ctx);
10669 raw_spin_unlock_irq(&ctx->lock);
10674 * Free an unexposed, unused context as created by inheritance by
10675 * perf_event_init_task below, used by fork() in case of fail.
10677 * Not all locks are strictly required, but take them anyway to be nice and
10678 * help out with the lockdep assertions.
10680 void perf_event_free_task(struct task_struct *task)
10682 struct perf_event_context *ctx;
10683 struct perf_event *event, *tmp;
10686 for_each_task_context_nr(ctxn) {
10687 ctx = task->perf_event_ctxp[ctxn];
10691 mutex_lock(&ctx->mutex);
10692 raw_spin_lock_irq(&ctx->lock);
10694 * Destroy the task <-> ctx relation and mark the context dead.
10696 * This is important because even though the task hasn't been
10697 * exposed yet the context has been (through child_list).
10699 RCU_INIT_POINTER(task->perf_event_ctxp[ctxn], NULL);
10700 WRITE_ONCE(ctx->task, TASK_TOMBSTONE);
10701 put_task_struct(task); /* cannot be last */
10702 raw_spin_unlock_irq(&ctx->lock);
10704 list_for_each_entry_safe(event, tmp, &ctx->event_list, event_entry)
10705 perf_free_event(event, ctx);
10707 mutex_unlock(&ctx->mutex);
10712 void perf_event_delayed_put(struct task_struct *task)
10716 for_each_task_context_nr(ctxn)
10717 WARN_ON_ONCE(task->perf_event_ctxp[ctxn]);
10720 struct file *perf_event_get(unsigned int fd)
10724 file = fget_raw(fd);
10726 return ERR_PTR(-EBADF);
10728 if (file->f_op != &perf_fops) {
10730 return ERR_PTR(-EBADF);
10736 const struct perf_event_attr *perf_event_attrs(struct perf_event *event)
10739 return ERR_PTR(-EINVAL);
10741 return &event->attr;
10745 * Inherit a event from parent task to child task.
10748 * - valid pointer on success
10749 * - NULL for orphaned events
10750 * - IS_ERR() on error
10752 static struct perf_event *
10753 inherit_event(struct perf_event *parent_event,
10754 struct task_struct *parent,
10755 struct perf_event_context *parent_ctx,
10756 struct task_struct *child,
10757 struct perf_event *group_leader,
10758 struct perf_event_context *child_ctx)
10760 enum perf_event_active_state parent_state = parent_event->state;
10761 struct perf_event *child_event;
10762 unsigned long flags;
10765 * Instead of creating recursive hierarchies of events,
10766 * we link inherited events back to the original parent,
10767 * which has a filp for sure, which we use as the reference
10770 if (parent_event->parent)
10771 parent_event = parent_event->parent;
10773 child_event = perf_event_alloc(&parent_event->attr,
10776 group_leader, parent_event,
10778 if (IS_ERR(child_event))
10779 return child_event;
10782 * is_orphaned_event() and list_add_tail(&parent_event->child_list)
10783 * must be under the same lock in order to serialize against
10784 * perf_event_release_kernel(), such that either we must observe
10785 * is_orphaned_event() or they will observe us on the child_list.
10787 mutex_lock(&parent_event->child_mutex);
10788 if (is_orphaned_event(parent_event) ||
10789 !atomic_long_inc_not_zero(&parent_event->refcount)) {
10790 mutex_unlock(&parent_event->child_mutex);
10791 free_event(child_event);
10795 get_ctx(child_ctx);
10798 * Make the child state follow the state of the parent event,
10799 * not its attr.disabled bit. We hold the parent's mutex,
10800 * so we won't race with perf_event_{en, dis}able_family.
10802 if (parent_state >= PERF_EVENT_STATE_INACTIVE)
10803 child_event->state = PERF_EVENT_STATE_INACTIVE;
10805 child_event->state = PERF_EVENT_STATE_OFF;
10807 if (parent_event->attr.freq) {
10808 u64 sample_period = parent_event->hw.sample_period;
10809 struct hw_perf_event *hwc = &child_event->hw;
10811 hwc->sample_period = sample_period;
10812 hwc->last_period = sample_period;
10814 local64_set(&hwc->period_left, sample_period);
10817 child_event->ctx = child_ctx;
10818 child_event->overflow_handler = parent_event->overflow_handler;
10819 child_event->overflow_handler_context
10820 = parent_event->overflow_handler_context;
10823 * Precalculate sample_data sizes
10825 perf_event__header_size(child_event);
10826 perf_event__id_header_size(child_event);
10829 * Link it up in the child's context:
10831 raw_spin_lock_irqsave(&child_ctx->lock, flags);
10832 add_event_to_ctx(child_event, child_ctx);
10833 raw_spin_unlock_irqrestore(&child_ctx->lock, flags);
10836 * Link this into the parent event's child list
10838 list_add_tail(&child_event->child_list, &parent_event->child_list);
10839 mutex_unlock(&parent_event->child_mutex);
10841 return child_event;
10845 * Inherits an event group.
10847 * This will quietly suppress orphaned events; !inherit_event() is not an error.
10848 * This matches with perf_event_release_kernel() removing all child events.
10854 static int inherit_group(struct perf_event *parent_event,
10855 struct task_struct *parent,
10856 struct perf_event_context *parent_ctx,
10857 struct task_struct *child,
10858 struct perf_event_context *child_ctx)
10860 struct perf_event *leader;
10861 struct perf_event *sub;
10862 struct perf_event *child_ctr;
10864 leader = inherit_event(parent_event, parent, parent_ctx,
10865 child, NULL, child_ctx);
10866 if (IS_ERR(leader))
10867 return PTR_ERR(leader);
10869 * @leader can be NULL here because of is_orphaned_event(). In this
10870 * case inherit_event() will create individual events, similar to what
10871 * perf_group_detach() would do anyway.
10873 list_for_each_entry(sub, &parent_event->sibling_list, group_entry) {
10874 child_ctr = inherit_event(sub, parent, parent_ctx,
10875 child, leader, child_ctx);
10876 if (IS_ERR(child_ctr))
10877 return PTR_ERR(child_ctr);
10883 * Creates the child task context and tries to inherit the event-group.
10885 * Clears @inherited_all on !attr.inherited or error. Note that we'll leave
10886 * inherited_all set when we 'fail' to inherit an orphaned event; this is
10887 * consistent with perf_event_release_kernel() removing all child events.
10894 inherit_task_group(struct perf_event *event, struct task_struct *parent,
10895 struct perf_event_context *parent_ctx,
10896 struct task_struct *child, int ctxn,
10897 int *inherited_all)
10900 struct perf_event_context *child_ctx;
10902 if (!event->attr.inherit) {
10903 *inherited_all = 0;
10907 child_ctx = child->perf_event_ctxp[ctxn];
10910 * This is executed from the parent task context, so
10911 * inherit events that have been marked for cloning.
10912 * First allocate and initialize a context for the
10915 child_ctx = alloc_perf_context(parent_ctx->pmu, child);
10919 child->perf_event_ctxp[ctxn] = child_ctx;
10922 ret = inherit_group(event, parent, parent_ctx,
10926 *inherited_all = 0;
10932 * Initialize the perf_event context in task_struct
10934 static int perf_event_init_context(struct task_struct *child, int ctxn)
10936 struct perf_event_context *child_ctx, *parent_ctx;
10937 struct perf_event_context *cloned_ctx;
10938 struct perf_event *event;
10939 struct task_struct *parent = current;
10940 int inherited_all = 1;
10941 unsigned long flags;
10944 if (likely(!parent->perf_event_ctxp[ctxn]))
10948 * If the parent's context is a clone, pin it so it won't get
10949 * swapped under us.
10951 parent_ctx = perf_pin_task_context(parent, ctxn);
10956 * No need to check if parent_ctx != NULL here; since we saw
10957 * it non-NULL earlier, the only reason for it to become NULL
10958 * is if we exit, and since we're currently in the middle of
10959 * a fork we can't be exiting at the same time.
10963 * Lock the parent list. No need to lock the child - not PID
10964 * hashed yet and not running, so nobody can access it.
10966 mutex_lock(&parent_ctx->mutex);
10969 * We dont have to disable NMIs - we are only looking at
10970 * the list, not manipulating it:
10972 list_for_each_entry(event, &parent_ctx->pinned_groups, group_entry) {
10973 ret = inherit_task_group(event, parent, parent_ctx,
10974 child, ctxn, &inherited_all);
10980 * We can't hold ctx->lock when iterating the ->flexible_group list due
10981 * to allocations, but we need to prevent rotation because
10982 * rotate_ctx() will change the list from interrupt context.
10984 raw_spin_lock_irqsave(&parent_ctx->lock, flags);
10985 parent_ctx->rotate_disable = 1;
10986 raw_spin_unlock_irqrestore(&parent_ctx->lock, flags);
10988 list_for_each_entry(event, &parent_ctx->flexible_groups, group_entry) {
10989 ret = inherit_task_group(event, parent, parent_ctx,
10990 child, ctxn, &inherited_all);
10995 raw_spin_lock_irqsave(&parent_ctx->lock, flags);
10996 parent_ctx->rotate_disable = 0;
10998 child_ctx = child->perf_event_ctxp[ctxn];
11000 if (child_ctx && inherited_all) {
11002 * Mark the child context as a clone of the parent
11003 * context, or of whatever the parent is a clone of.
11005 * Note that if the parent is a clone, the holding of
11006 * parent_ctx->lock avoids it from being uncloned.
11008 cloned_ctx = parent_ctx->parent_ctx;
11010 child_ctx->parent_ctx = cloned_ctx;
11011 child_ctx->parent_gen = parent_ctx->parent_gen;
11013 child_ctx->parent_ctx = parent_ctx;
11014 child_ctx->parent_gen = parent_ctx->generation;
11016 get_ctx(child_ctx->parent_ctx);
11019 raw_spin_unlock_irqrestore(&parent_ctx->lock, flags);
11021 mutex_unlock(&parent_ctx->mutex);
11023 perf_unpin_context(parent_ctx);
11024 put_ctx(parent_ctx);
11030 * Initialize the perf_event context in task_struct
11032 int perf_event_init_task(struct task_struct *child)
11036 memset(child->perf_event_ctxp, 0, sizeof(child->perf_event_ctxp));
11037 mutex_init(&child->perf_event_mutex);
11038 INIT_LIST_HEAD(&child->perf_event_list);
11040 for_each_task_context_nr(ctxn) {
11041 ret = perf_event_init_context(child, ctxn);
11043 perf_event_free_task(child);
11051 static void __init perf_event_init_all_cpus(void)
11053 struct swevent_htable *swhash;
11056 zalloc_cpumask_var(&perf_online_mask, GFP_KERNEL);
11058 for_each_possible_cpu(cpu) {
11059 swhash = &per_cpu(swevent_htable, cpu);
11060 mutex_init(&swhash->hlist_mutex);
11061 INIT_LIST_HEAD(&per_cpu(active_ctx_list, cpu));
11063 INIT_LIST_HEAD(&per_cpu(pmu_sb_events.list, cpu));
11064 raw_spin_lock_init(&per_cpu(pmu_sb_events.lock, cpu));
11066 #ifdef CONFIG_CGROUP_PERF
11067 INIT_LIST_HEAD(&per_cpu(cgrp_cpuctx_list, cpu));
11069 INIT_LIST_HEAD(&per_cpu(sched_cb_list, cpu));
11073 void perf_swevent_init_cpu(unsigned int cpu)
11075 struct swevent_htable *swhash = &per_cpu(swevent_htable, cpu);
11077 mutex_lock(&swhash->hlist_mutex);
11078 if (swhash->hlist_refcount > 0 && !swevent_hlist_deref(swhash)) {
11079 struct swevent_hlist *hlist;
11081 hlist = kzalloc_node(sizeof(*hlist), GFP_KERNEL, cpu_to_node(cpu));
11083 rcu_assign_pointer(swhash->swevent_hlist, hlist);
11085 mutex_unlock(&swhash->hlist_mutex);
11088 #if defined CONFIG_HOTPLUG_CPU || defined CONFIG_KEXEC_CORE
11089 static void __perf_event_exit_context(void *__info)
11091 struct perf_event_context *ctx = __info;
11092 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
11093 struct perf_event *event;
11095 raw_spin_lock(&ctx->lock);
11096 list_for_each_entry(event, &ctx->event_list, event_entry)
11097 __perf_remove_from_context(event, cpuctx, ctx, (void *)DETACH_GROUP);
11098 raw_spin_unlock(&ctx->lock);
11101 static void perf_event_exit_cpu_context(int cpu)
11103 struct perf_cpu_context *cpuctx;
11104 struct perf_event_context *ctx;
11107 mutex_lock(&pmus_lock);
11108 list_for_each_entry(pmu, &pmus, entry) {
11109 cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
11110 ctx = &cpuctx->ctx;
11112 mutex_lock(&ctx->mutex);
11113 smp_call_function_single(cpu, __perf_event_exit_context, ctx, 1);
11114 cpuctx->online = 0;
11115 mutex_unlock(&ctx->mutex);
11117 cpumask_clear_cpu(cpu, perf_online_mask);
11118 mutex_unlock(&pmus_lock);
11122 static void perf_event_exit_cpu_context(int cpu) { }
11126 int perf_event_init_cpu(unsigned int cpu)
11128 struct perf_cpu_context *cpuctx;
11129 struct perf_event_context *ctx;
11132 perf_swevent_init_cpu(cpu);
11134 mutex_lock(&pmus_lock);
11135 cpumask_set_cpu(cpu, perf_online_mask);
11136 list_for_each_entry(pmu, &pmus, entry) {
11137 cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
11138 ctx = &cpuctx->ctx;
11140 mutex_lock(&ctx->mutex);
11141 cpuctx->online = 1;
11142 mutex_unlock(&ctx->mutex);
11144 mutex_unlock(&pmus_lock);
11149 int perf_event_exit_cpu(unsigned int cpu)
11151 perf_event_exit_cpu_context(cpu);
11156 perf_reboot(struct notifier_block *notifier, unsigned long val, void *v)
11160 for_each_online_cpu(cpu)
11161 perf_event_exit_cpu(cpu);
11167 * Run the perf reboot notifier at the very last possible moment so that
11168 * the generic watchdog code runs as long as possible.
11170 static struct notifier_block perf_reboot_notifier = {
11171 .notifier_call = perf_reboot,
11172 .priority = INT_MIN,
11175 void __init perf_event_init(void)
11179 idr_init(&pmu_idr);
11181 perf_event_init_all_cpus();
11182 init_srcu_struct(&pmus_srcu);
11183 perf_pmu_register(&perf_swevent, "software", PERF_TYPE_SOFTWARE);
11184 perf_pmu_register(&perf_cpu_clock, NULL, -1);
11185 perf_pmu_register(&perf_task_clock, NULL, -1);
11186 perf_tp_register();
11187 perf_event_init_cpu(smp_processor_id());
11188 register_reboot_notifier(&perf_reboot_notifier);
11190 ret = init_hw_breakpoint();
11191 WARN(ret, "hw_breakpoint initialization failed with: %d", ret);
11194 * Build time assertion that we keep the data_head at the intended
11195 * location. IOW, validation we got the __reserved[] size right.
11197 BUILD_BUG_ON((offsetof(struct perf_event_mmap_page, data_head))
11201 ssize_t perf_event_sysfs_show(struct device *dev, struct device_attribute *attr,
11204 struct perf_pmu_events_attr *pmu_attr =
11205 container_of(attr, struct perf_pmu_events_attr, attr);
11207 if (pmu_attr->event_str)
11208 return sprintf(page, "%s\n", pmu_attr->event_str);
11212 EXPORT_SYMBOL_GPL(perf_event_sysfs_show);
11214 static int __init perf_event_sysfs_init(void)
11219 mutex_lock(&pmus_lock);
11221 ret = bus_register(&pmu_bus);
11225 list_for_each_entry(pmu, &pmus, entry) {
11226 if (!pmu->name || pmu->type < 0)
11229 ret = pmu_dev_alloc(pmu);
11230 WARN(ret, "Failed to register pmu: %s, reason %d\n", pmu->name, ret);
11232 pmu_bus_running = 1;
11236 mutex_unlock(&pmus_lock);
11240 device_initcall(perf_event_sysfs_init);
11242 #ifdef CONFIG_CGROUP_PERF
11243 static struct cgroup_subsys_state *
11244 perf_cgroup_css_alloc(struct cgroup_subsys_state *parent_css)
11246 struct perf_cgroup *jc;
11248 jc = kzalloc(sizeof(*jc), GFP_KERNEL);
11250 return ERR_PTR(-ENOMEM);
11252 jc->info = alloc_percpu(struct perf_cgroup_info);
11255 return ERR_PTR(-ENOMEM);
11261 static void perf_cgroup_css_free(struct cgroup_subsys_state *css)
11263 struct perf_cgroup *jc = container_of(css, struct perf_cgroup, css);
11265 free_percpu(jc->info);
11269 static int __perf_cgroup_move(void *info)
11271 struct task_struct *task = info;
11273 perf_cgroup_switch(task, PERF_CGROUP_SWOUT | PERF_CGROUP_SWIN);
11278 static void perf_cgroup_attach(struct cgroup_taskset *tset)
11280 struct task_struct *task;
11281 struct cgroup_subsys_state *css;
11283 cgroup_taskset_for_each(task, css, tset)
11284 task_function_call(task, __perf_cgroup_move, task);
11287 struct cgroup_subsys perf_event_cgrp_subsys = {
11288 .css_alloc = perf_cgroup_css_alloc,
11289 .css_free = perf_cgroup_css_free,
11290 .attach = perf_cgroup_attach,
11292 * Implicitly enable on dfl hierarchy so that perf events can
11293 * always be filtered by cgroup2 path as long as perf_event
11294 * controller is not mounted on a legacy hierarchy.
11296 .implicit_on_dfl = true,
11299 #endif /* CONFIG_CGROUP_PERF */