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>
54 #include <asm/irq_regs.h>
56 typedef int (*remote_function_f)(void *);
58 struct remote_function_call {
59 struct task_struct *p;
60 remote_function_f func;
65 static void remote_function(void *data)
67 struct remote_function_call *tfc = data;
68 struct task_struct *p = tfc->p;
72 if (task_cpu(p) != smp_processor_id())
76 * Now that we're on right CPU with IRQs disabled, we can test
77 * if we hit the right task without races.
80 tfc->ret = -ESRCH; /* No such (running) process */
85 tfc->ret = tfc->func(tfc->info);
89 * task_function_call - call a function on the cpu on which a task runs
90 * @p: the task to evaluate
91 * @func: the function to be called
92 * @info: the function call argument
94 * Calls the function @func when the task is currently running. This might
95 * be on the current CPU, which just calls the function directly
97 * returns: @func return value, or
98 * -ESRCH - when the process isn't running
99 * -EAGAIN - when the process moved away
102 task_function_call(struct task_struct *p, remote_function_f func, void *info)
104 struct remote_function_call data = {
113 ret = smp_call_function_single(task_cpu(p), remote_function, &data, 1);
116 } while (ret == -EAGAIN);
122 * cpu_function_call - call a function on the cpu
123 * @func: the function to be called
124 * @info: the function call argument
126 * Calls the function @func on the remote cpu.
128 * returns: @func return value or -ENXIO when the cpu is offline
130 static int cpu_function_call(int cpu, remote_function_f func, void *info)
132 struct remote_function_call data = {
136 .ret = -ENXIO, /* No such CPU */
139 smp_call_function_single(cpu, remote_function, &data, 1);
144 static inline struct perf_cpu_context *
145 __get_cpu_context(struct perf_event_context *ctx)
147 return this_cpu_ptr(ctx->pmu->pmu_cpu_context);
150 static void perf_ctx_lock(struct perf_cpu_context *cpuctx,
151 struct perf_event_context *ctx)
153 raw_spin_lock(&cpuctx->ctx.lock);
155 raw_spin_lock(&ctx->lock);
158 static void perf_ctx_unlock(struct perf_cpu_context *cpuctx,
159 struct perf_event_context *ctx)
162 raw_spin_unlock(&ctx->lock);
163 raw_spin_unlock(&cpuctx->ctx.lock);
166 #define TASK_TOMBSTONE ((void *)-1L)
168 static bool is_kernel_event(struct perf_event *event)
170 return READ_ONCE(event->owner) == TASK_TOMBSTONE;
174 * On task ctx scheduling...
176 * When !ctx->nr_events a task context will not be scheduled. This means
177 * we can disable the scheduler hooks (for performance) without leaving
178 * pending task ctx state.
180 * This however results in two special cases:
182 * - removing the last event from a task ctx; this is relatively straight
183 * forward and is done in __perf_remove_from_context.
185 * - adding the first event to a task ctx; this is tricky because we cannot
186 * rely on ctx->is_active and therefore cannot use event_function_call().
187 * See perf_install_in_context().
189 * If ctx->nr_events, then ctx->is_active and cpuctx->task_ctx are set.
192 typedef void (*event_f)(struct perf_event *, struct perf_cpu_context *,
193 struct perf_event_context *, void *);
195 struct event_function_struct {
196 struct perf_event *event;
201 static int event_function(void *info)
203 struct event_function_struct *efs = info;
204 struct perf_event *event = efs->event;
205 struct perf_event_context *ctx = event->ctx;
206 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
207 struct perf_event_context *task_ctx = cpuctx->task_ctx;
210 WARN_ON_ONCE(!irqs_disabled());
212 perf_ctx_lock(cpuctx, task_ctx);
214 * Since we do the IPI call without holding ctx->lock things can have
215 * changed, double check we hit the task we set out to hit.
218 if (ctx->task != current) {
224 * We only use event_function_call() on established contexts,
225 * and event_function() is only ever called when active (or
226 * rather, we'll have bailed in task_function_call() or the
227 * above ctx->task != current test), therefore we must have
228 * ctx->is_active here.
230 WARN_ON_ONCE(!ctx->is_active);
232 * And since we have ctx->is_active, cpuctx->task_ctx must
235 WARN_ON_ONCE(task_ctx != ctx);
237 WARN_ON_ONCE(&cpuctx->ctx != ctx);
240 efs->func(event, cpuctx, ctx, efs->data);
242 perf_ctx_unlock(cpuctx, task_ctx);
247 static void event_function_call(struct perf_event *event, event_f func, void *data)
249 struct perf_event_context *ctx = event->ctx;
250 struct task_struct *task = READ_ONCE(ctx->task); /* verified in event_function */
251 struct event_function_struct efs = {
257 if (!event->parent) {
259 * If this is a !child event, we must hold ctx::mutex to
260 * stabilize the the event->ctx relation. See
261 * perf_event_ctx_lock().
263 lockdep_assert_held(&ctx->mutex);
267 cpu_function_call(event->cpu, event_function, &efs);
271 if (task == TASK_TOMBSTONE)
275 if (!task_function_call(task, event_function, &efs))
278 raw_spin_lock_irq(&ctx->lock);
280 * Reload the task pointer, it might have been changed by
281 * a concurrent perf_event_context_sched_out().
284 if (task == TASK_TOMBSTONE) {
285 raw_spin_unlock_irq(&ctx->lock);
288 if (ctx->is_active) {
289 raw_spin_unlock_irq(&ctx->lock);
292 func(event, NULL, ctx, data);
293 raw_spin_unlock_irq(&ctx->lock);
297 * Similar to event_function_call() + event_function(), but hard assumes IRQs
298 * are already disabled and we're on the right CPU.
300 static void event_function_local(struct perf_event *event, event_f func, void *data)
302 struct perf_event_context *ctx = event->ctx;
303 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
304 struct task_struct *task = READ_ONCE(ctx->task);
305 struct perf_event_context *task_ctx = NULL;
307 WARN_ON_ONCE(!irqs_disabled());
310 if (task == TASK_TOMBSTONE)
316 perf_ctx_lock(cpuctx, task_ctx);
319 if (task == TASK_TOMBSTONE)
324 * We must be either inactive or active and the right task,
325 * otherwise we're screwed, since we cannot IPI to somewhere
328 if (ctx->is_active) {
329 if (WARN_ON_ONCE(task != current))
332 if (WARN_ON_ONCE(cpuctx->task_ctx != ctx))
336 WARN_ON_ONCE(&cpuctx->ctx != ctx);
339 func(event, cpuctx, ctx, data);
341 perf_ctx_unlock(cpuctx, task_ctx);
344 #define PERF_FLAG_ALL (PERF_FLAG_FD_NO_GROUP |\
345 PERF_FLAG_FD_OUTPUT |\
346 PERF_FLAG_PID_CGROUP |\
347 PERF_FLAG_FD_CLOEXEC)
350 * branch priv levels that need permission checks
352 #define PERF_SAMPLE_BRANCH_PERM_PLM \
353 (PERF_SAMPLE_BRANCH_KERNEL |\
354 PERF_SAMPLE_BRANCH_HV)
357 EVENT_FLEXIBLE = 0x1,
360 /* see ctx_resched() for details */
362 EVENT_ALL = EVENT_FLEXIBLE | EVENT_PINNED,
366 * perf_sched_events : >0 events exist
367 * perf_cgroup_events: >0 per-cpu cgroup events exist on this cpu
370 static void perf_sched_delayed(struct work_struct *work);
371 DEFINE_STATIC_KEY_FALSE(perf_sched_events);
372 static DECLARE_DELAYED_WORK(perf_sched_work, perf_sched_delayed);
373 static DEFINE_MUTEX(perf_sched_mutex);
374 static atomic_t perf_sched_count;
376 static DEFINE_PER_CPU(atomic_t, perf_cgroup_events);
377 static DEFINE_PER_CPU(int, perf_sched_cb_usages);
378 static DEFINE_PER_CPU(struct pmu_event_list, pmu_sb_events);
380 static atomic_t nr_mmap_events __read_mostly;
381 static atomic_t nr_comm_events __read_mostly;
382 static atomic_t nr_task_events __read_mostly;
383 static atomic_t nr_freq_events __read_mostly;
384 static atomic_t nr_switch_events __read_mostly;
386 static LIST_HEAD(pmus);
387 static DEFINE_MUTEX(pmus_lock);
388 static struct srcu_struct pmus_srcu;
391 * perf event paranoia level:
392 * -1 - not paranoid at all
393 * 0 - disallow raw tracepoint access for unpriv
394 * 1 - disallow cpu events for unpriv
395 * 2 - disallow kernel profiling for unpriv
397 int sysctl_perf_event_paranoid __read_mostly = 2;
399 /* Minimum for 512 kiB + 1 user control page */
400 int sysctl_perf_event_mlock __read_mostly = 512 + (PAGE_SIZE / 1024); /* 'free' kiB per user */
403 * max perf event sample rate
405 #define DEFAULT_MAX_SAMPLE_RATE 100000
406 #define DEFAULT_SAMPLE_PERIOD_NS (NSEC_PER_SEC / DEFAULT_MAX_SAMPLE_RATE)
407 #define DEFAULT_CPU_TIME_MAX_PERCENT 25
409 int sysctl_perf_event_sample_rate __read_mostly = DEFAULT_MAX_SAMPLE_RATE;
411 static int max_samples_per_tick __read_mostly = DIV_ROUND_UP(DEFAULT_MAX_SAMPLE_RATE, HZ);
412 static int perf_sample_period_ns __read_mostly = DEFAULT_SAMPLE_PERIOD_NS;
414 static int perf_sample_allowed_ns __read_mostly =
415 DEFAULT_SAMPLE_PERIOD_NS * DEFAULT_CPU_TIME_MAX_PERCENT / 100;
417 static void update_perf_cpu_limits(void)
419 u64 tmp = perf_sample_period_ns;
421 tmp *= sysctl_perf_cpu_time_max_percent;
422 tmp = div_u64(tmp, 100);
426 WRITE_ONCE(perf_sample_allowed_ns, tmp);
429 static int perf_rotate_context(struct perf_cpu_context *cpuctx);
431 int perf_proc_update_handler(struct ctl_table *table, int write,
432 void __user *buffer, size_t *lenp,
435 int ret = proc_dointvec_minmax(table, write, buffer, lenp, ppos);
441 * If throttling is disabled don't allow the write:
443 if (sysctl_perf_cpu_time_max_percent == 100 ||
444 sysctl_perf_cpu_time_max_percent == 0)
447 max_samples_per_tick = DIV_ROUND_UP(sysctl_perf_event_sample_rate, HZ);
448 perf_sample_period_ns = NSEC_PER_SEC / sysctl_perf_event_sample_rate;
449 update_perf_cpu_limits();
454 int sysctl_perf_cpu_time_max_percent __read_mostly = DEFAULT_CPU_TIME_MAX_PERCENT;
456 int perf_cpu_time_max_percent_handler(struct ctl_table *table, int write,
457 void __user *buffer, size_t *lenp,
460 int ret = proc_dointvec_minmax(table, write, buffer, lenp, ppos);
465 if (sysctl_perf_cpu_time_max_percent == 100 ||
466 sysctl_perf_cpu_time_max_percent == 0) {
468 "perf: Dynamic interrupt throttling disabled, can hang your system!\n");
469 WRITE_ONCE(perf_sample_allowed_ns, 0);
471 update_perf_cpu_limits();
478 * perf samples are done in some very critical code paths (NMIs).
479 * If they take too much CPU time, the system can lock up and not
480 * get any real work done. This will drop the sample rate when
481 * we detect that events are taking too long.
483 #define NR_ACCUMULATED_SAMPLES 128
484 static DEFINE_PER_CPU(u64, running_sample_length);
486 static u64 __report_avg;
487 static u64 __report_allowed;
489 static void perf_duration_warn(struct irq_work *w)
491 printk_ratelimited(KERN_INFO
492 "perf: interrupt took too long (%lld > %lld), lowering "
493 "kernel.perf_event_max_sample_rate to %d\n",
494 __report_avg, __report_allowed,
495 sysctl_perf_event_sample_rate);
498 static DEFINE_IRQ_WORK(perf_duration_work, perf_duration_warn);
500 void perf_sample_event_took(u64 sample_len_ns)
502 u64 max_len = READ_ONCE(perf_sample_allowed_ns);
510 /* Decay the counter by 1 average sample. */
511 running_len = __this_cpu_read(running_sample_length);
512 running_len -= running_len/NR_ACCUMULATED_SAMPLES;
513 running_len += sample_len_ns;
514 __this_cpu_write(running_sample_length, running_len);
517 * Note: this will be biased artifically low until we have
518 * seen NR_ACCUMULATED_SAMPLES. Doing it this way keeps us
519 * from having to maintain a count.
521 avg_len = running_len/NR_ACCUMULATED_SAMPLES;
522 if (avg_len <= max_len)
525 __report_avg = avg_len;
526 __report_allowed = max_len;
529 * Compute a throttle threshold 25% below the current duration.
531 avg_len += avg_len / 4;
532 max = (TICK_NSEC / 100) * sysctl_perf_cpu_time_max_percent;
538 WRITE_ONCE(perf_sample_allowed_ns, avg_len);
539 WRITE_ONCE(max_samples_per_tick, max);
541 sysctl_perf_event_sample_rate = max * HZ;
542 perf_sample_period_ns = NSEC_PER_SEC / sysctl_perf_event_sample_rate;
544 if (!irq_work_queue(&perf_duration_work)) {
545 early_printk("perf: interrupt took too long (%lld > %lld), lowering "
546 "kernel.perf_event_max_sample_rate to %d\n",
547 __report_avg, __report_allowed,
548 sysctl_perf_event_sample_rate);
552 static atomic64_t perf_event_id;
554 static void cpu_ctx_sched_out(struct perf_cpu_context *cpuctx,
555 enum event_type_t event_type);
557 static void cpu_ctx_sched_in(struct perf_cpu_context *cpuctx,
558 enum event_type_t event_type,
559 struct task_struct *task);
561 static void update_context_time(struct perf_event_context *ctx);
562 static u64 perf_event_time(struct perf_event *event);
564 void __weak perf_event_print_debug(void) { }
566 extern __weak const char *perf_pmu_name(void)
571 static inline u64 perf_clock(void)
573 return local_clock();
576 static inline u64 perf_event_clock(struct perf_event *event)
578 return event->clock();
581 #ifdef CONFIG_CGROUP_PERF
584 perf_cgroup_match(struct perf_event *event)
586 struct perf_event_context *ctx = event->ctx;
587 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
589 /* @event doesn't care about cgroup */
593 /* wants specific cgroup scope but @cpuctx isn't associated with any */
598 * Cgroup scoping is recursive. An event enabled for a cgroup is
599 * also enabled for all its descendant cgroups. If @cpuctx's
600 * cgroup is a descendant of @event's (the test covers identity
601 * case), it's a match.
603 return cgroup_is_descendant(cpuctx->cgrp->css.cgroup,
604 event->cgrp->css.cgroup);
607 static inline void perf_detach_cgroup(struct perf_event *event)
609 css_put(&event->cgrp->css);
613 static inline int is_cgroup_event(struct perf_event *event)
615 return event->cgrp != NULL;
618 static inline u64 perf_cgroup_event_time(struct perf_event *event)
620 struct perf_cgroup_info *t;
622 t = per_cpu_ptr(event->cgrp->info, event->cpu);
626 static inline void __update_cgrp_time(struct perf_cgroup *cgrp)
628 struct perf_cgroup_info *info;
633 info = this_cpu_ptr(cgrp->info);
635 info->time += now - info->timestamp;
636 info->timestamp = now;
639 static inline void update_cgrp_time_from_cpuctx(struct perf_cpu_context *cpuctx)
641 struct perf_cgroup *cgrp_out = cpuctx->cgrp;
643 __update_cgrp_time(cgrp_out);
646 static inline void update_cgrp_time_from_event(struct perf_event *event)
648 struct perf_cgroup *cgrp;
651 * ensure we access cgroup data only when needed and
652 * when we know the cgroup is pinned (css_get)
654 if (!is_cgroup_event(event))
657 cgrp = perf_cgroup_from_task(current, event->ctx);
659 * Do not update time when cgroup is not active
661 if (cgrp == event->cgrp)
662 __update_cgrp_time(event->cgrp);
666 perf_cgroup_set_timestamp(struct task_struct *task,
667 struct perf_event_context *ctx)
669 struct perf_cgroup *cgrp;
670 struct perf_cgroup_info *info;
673 * ctx->lock held by caller
674 * ensure we do not access cgroup data
675 * unless we have the cgroup pinned (css_get)
677 if (!task || !ctx->nr_cgroups)
680 cgrp = perf_cgroup_from_task(task, ctx);
681 info = this_cpu_ptr(cgrp->info);
682 info->timestamp = ctx->timestamp;
685 static DEFINE_PER_CPU(struct list_head, cgrp_cpuctx_list);
687 #define PERF_CGROUP_SWOUT 0x1 /* cgroup switch out every event */
688 #define PERF_CGROUP_SWIN 0x2 /* cgroup switch in events based on task */
691 * reschedule events based on the cgroup constraint of task.
693 * mode SWOUT : schedule out everything
694 * mode SWIN : schedule in based on cgroup for next
696 static void perf_cgroup_switch(struct task_struct *task, int mode)
698 struct perf_cpu_context *cpuctx;
699 struct list_head *list;
703 * Disable interrupts and preemption to avoid this CPU's
704 * cgrp_cpuctx_entry to change under us.
706 local_irq_save(flags);
708 list = this_cpu_ptr(&cgrp_cpuctx_list);
709 list_for_each_entry(cpuctx, list, cgrp_cpuctx_entry) {
710 WARN_ON_ONCE(cpuctx->ctx.nr_cgroups == 0);
712 perf_ctx_lock(cpuctx, cpuctx->task_ctx);
713 perf_pmu_disable(cpuctx->ctx.pmu);
715 if (mode & PERF_CGROUP_SWOUT) {
716 cpu_ctx_sched_out(cpuctx, EVENT_ALL);
718 * must not be done before ctxswout due
719 * to event_filter_match() in event_sched_out()
724 if (mode & PERF_CGROUP_SWIN) {
725 WARN_ON_ONCE(cpuctx->cgrp);
727 * set cgrp before ctxsw in to allow
728 * event_filter_match() to not have to pass
730 * we pass the cpuctx->ctx to perf_cgroup_from_task()
731 * because cgorup events are only per-cpu
733 cpuctx->cgrp = perf_cgroup_from_task(task,
735 cpu_ctx_sched_in(cpuctx, EVENT_ALL, task);
737 perf_pmu_enable(cpuctx->ctx.pmu);
738 perf_ctx_unlock(cpuctx, cpuctx->task_ctx);
741 local_irq_restore(flags);
744 static inline void perf_cgroup_sched_out(struct task_struct *task,
745 struct task_struct *next)
747 struct perf_cgroup *cgrp1;
748 struct perf_cgroup *cgrp2 = NULL;
752 * we come here when we know perf_cgroup_events > 0
753 * we do not need to pass the ctx here because we know
754 * we are holding the rcu lock
756 cgrp1 = perf_cgroup_from_task(task, NULL);
757 cgrp2 = perf_cgroup_from_task(next, NULL);
760 * only schedule out current cgroup events if we know
761 * that we are switching to a different cgroup. Otherwise,
762 * do no touch the cgroup events.
765 perf_cgroup_switch(task, PERF_CGROUP_SWOUT);
770 static inline void perf_cgroup_sched_in(struct task_struct *prev,
771 struct task_struct *task)
773 struct perf_cgroup *cgrp1;
774 struct perf_cgroup *cgrp2 = NULL;
778 * we come here when we know perf_cgroup_events > 0
779 * we do not need to pass the ctx here because we know
780 * we are holding the rcu lock
782 cgrp1 = perf_cgroup_from_task(task, NULL);
783 cgrp2 = perf_cgroup_from_task(prev, NULL);
786 * only need to schedule in cgroup events if we are changing
787 * cgroup during ctxsw. Cgroup events were not scheduled
788 * out of ctxsw out if that was not the case.
791 perf_cgroup_switch(task, PERF_CGROUP_SWIN);
796 static inline int perf_cgroup_connect(int fd, struct perf_event *event,
797 struct perf_event_attr *attr,
798 struct perf_event *group_leader)
800 struct perf_cgroup *cgrp;
801 struct cgroup_subsys_state *css;
802 struct fd f = fdget(fd);
808 css = css_tryget_online_from_dir(f.file->f_path.dentry,
809 &perf_event_cgrp_subsys);
815 cgrp = container_of(css, struct perf_cgroup, css);
819 * all events in a group must monitor
820 * the same cgroup because a task belongs
821 * to only one perf cgroup at a time
823 if (group_leader && group_leader->cgrp != cgrp) {
824 perf_detach_cgroup(event);
833 perf_cgroup_set_shadow_time(struct perf_event *event, u64 now)
835 struct perf_cgroup_info *t;
836 t = per_cpu_ptr(event->cgrp->info, event->cpu);
837 event->shadow_ctx_time = now - t->timestamp;
841 perf_cgroup_defer_enabled(struct perf_event *event)
844 * when the current task's perf cgroup does not match
845 * the event's, we need to remember to call the
846 * perf_mark_enable() function the first time a task with
847 * a matching perf cgroup is scheduled in.
849 if (is_cgroup_event(event) && !perf_cgroup_match(event))
850 event->cgrp_defer_enabled = 1;
854 perf_cgroup_mark_enabled(struct perf_event *event,
855 struct perf_event_context *ctx)
857 struct perf_event *sub;
858 u64 tstamp = perf_event_time(event);
860 if (!event->cgrp_defer_enabled)
863 event->cgrp_defer_enabled = 0;
865 event->tstamp_enabled = tstamp - event->total_time_enabled;
866 list_for_each_entry(sub, &event->sibling_list, group_entry) {
867 if (sub->state >= PERF_EVENT_STATE_INACTIVE) {
868 sub->tstamp_enabled = tstamp - sub->total_time_enabled;
869 sub->cgrp_defer_enabled = 0;
875 * Update cpuctx->cgrp so that it is set when first cgroup event is added and
876 * cleared when last cgroup event is removed.
879 list_update_cgroup_event(struct perf_event *event,
880 struct perf_event_context *ctx, bool add)
882 struct perf_cpu_context *cpuctx;
883 struct list_head *cpuctx_entry;
885 if (!is_cgroup_event(event))
888 if (add && ctx->nr_cgroups++)
890 else if (!add && --ctx->nr_cgroups)
893 * Because cgroup events are always per-cpu events,
894 * this will always be called from the right CPU.
896 cpuctx = __get_cpu_context(ctx);
897 cpuctx_entry = &cpuctx->cgrp_cpuctx_entry;
898 /* cpuctx->cgrp is NULL unless a cgroup event is active in this CPU .*/
900 list_add(cpuctx_entry, this_cpu_ptr(&cgrp_cpuctx_list));
901 if (perf_cgroup_from_task(current, ctx) == event->cgrp)
902 cpuctx->cgrp = event->cgrp;
904 list_del(cpuctx_entry);
909 #else /* !CONFIG_CGROUP_PERF */
912 perf_cgroup_match(struct perf_event *event)
917 static inline void perf_detach_cgroup(struct perf_event *event)
920 static inline int is_cgroup_event(struct perf_event *event)
925 static inline u64 perf_cgroup_event_cgrp_time(struct perf_event *event)
930 static inline void update_cgrp_time_from_event(struct perf_event *event)
934 static inline void update_cgrp_time_from_cpuctx(struct perf_cpu_context *cpuctx)
938 static inline void perf_cgroup_sched_out(struct task_struct *task,
939 struct task_struct *next)
943 static inline void perf_cgroup_sched_in(struct task_struct *prev,
944 struct task_struct *task)
948 static inline int perf_cgroup_connect(pid_t pid, struct perf_event *event,
949 struct perf_event_attr *attr,
950 struct perf_event *group_leader)
956 perf_cgroup_set_timestamp(struct task_struct *task,
957 struct perf_event_context *ctx)
962 perf_cgroup_switch(struct task_struct *task, struct task_struct *next)
967 perf_cgroup_set_shadow_time(struct perf_event *event, u64 now)
971 static inline u64 perf_cgroup_event_time(struct perf_event *event)
977 perf_cgroup_defer_enabled(struct perf_event *event)
982 perf_cgroup_mark_enabled(struct perf_event *event,
983 struct perf_event_context *ctx)
988 list_update_cgroup_event(struct perf_event *event,
989 struct perf_event_context *ctx, bool add)
996 * set default to be dependent on timer tick just
999 #define PERF_CPU_HRTIMER (1000 / HZ)
1001 * function must be called with interrupts disbled
1003 static enum hrtimer_restart perf_mux_hrtimer_handler(struct hrtimer *hr)
1005 struct perf_cpu_context *cpuctx;
1008 WARN_ON(!irqs_disabled());
1010 cpuctx = container_of(hr, struct perf_cpu_context, hrtimer);
1011 rotations = perf_rotate_context(cpuctx);
1013 raw_spin_lock(&cpuctx->hrtimer_lock);
1015 hrtimer_forward_now(hr, cpuctx->hrtimer_interval);
1017 cpuctx->hrtimer_active = 0;
1018 raw_spin_unlock(&cpuctx->hrtimer_lock);
1020 return rotations ? HRTIMER_RESTART : HRTIMER_NORESTART;
1023 static void __perf_mux_hrtimer_init(struct perf_cpu_context *cpuctx, int cpu)
1025 struct hrtimer *timer = &cpuctx->hrtimer;
1026 struct pmu *pmu = cpuctx->ctx.pmu;
1029 /* no multiplexing needed for SW PMU */
1030 if (pmu->task_ctx_nr == perf_sw_context)
1034 * check default is sane, if not set then force to
1035 * default interval (1/tick)
1037 interval = pmu->hrtimer_interval_ms;
1039 interval = pmu->hrtimer_interval_ms = PERF_CPU_HRTIMER;
1041 cpuctx->hrtimer_interval = ns_to_ktime(NSEC_PER_MSEC * interval);
1043 raw_spin_lock_init(&cpuctx->hrtimer_lock);
1044 hrtimer_init(timer, CLOCK_MONOTONIC, HRTIMER_MODE_ABS_PINNED);
1045 timer->function = perf_mux_hrtimer_handler;
1048 static int perf_mux_hrtimer_restart(struct perf_cpu_context *cpuctx)
1050 struct hrtimer *timer = &cpuctx->hrtimer;
1051 struct pmu *pmu = cpuctx->ctx.pmu;
1052 unsigned long flags;
1054 /* not for SW PMU */
1055 if (pmu->task_ctx_nr == perf_sw_context)
1058 raw_spin_lock_irqsave(&cpuctx->hrtimer_lock, flags);
1059 if (!cpuctx->hrtimer_active) {
1060 cpuctx->hrtimer_active = 1;
1061 hrtimer_forward_now(timer, cpuctx->hrtimer_interval);
1062 hrtimer_start_expires(timer, HRTIMER_MODE_ABS_PINNED);
1064 raw_spin_unlock_irqrestore(&cpuctx->hrtimer_lock, flags);
1069 void perf_pmu_disable(struct pmu *pmu)
1071 int *count = this_cpu_ptr(pmu->pmu_disable_count);
1073 pmu->pmu_disable(pmu);
1076 void perf_pmu_enable(struct pmu *pmu)
1078 int *count = this_cpu_ptr(pmu->pmu_disable_count);
1080 pmu->pmu_enable(pmu);
1083 static DEFINE_PER_CPU(struct list_head, active_ctx_list);
1086 * perf_event_ctx_activate(), perf_event_ctx_deactivate(), and
1087 * perf_event_task_tick() are fully serialized because they're strictly cpu
1088 * affine and perf_event_ctx{activate,deactivate} are called with IRQs
1089 * disabled, while perf_event_task_tick is called from IRQ context.
1091 static void perf_event_ctx_activate(struct perf_event_context *ctx)
1093 struct list_head *head = this_cpu_ptr(&active_ctx_list);
1095 WARN_ON(!irqs_disabled());
1097 WARN_ON(!list_empty(&ctx->active_ctx_list));
1099 list_add(&ctx->active_ctx_list, head);
1102 static void perf_event_ctx_deactivate(struct perf_event_context *ctx)
1104 WARN_ON(!irqs_disabled());
1106 WARN_ON(list_empty(&ctx->active_ctx_list));
1108 list_del_init(&ctx->active_ctx_list);
1111 static void get_ctx(struct perf_event_context *ctx)
1113 WARN_ON(!atomic_inc_not_zero(&ctx->refcount));
1116 static void free_ctx(struct rcu_head *head)
1118 struct perf_event_context *ctx;
1120 ctx = container_of(head, struct perf_event_context, rcu_head);
1121 kfree(ctx->task_ctx_data);
1125 static void put_ctx(struct perf_event_context *ctx)
1127 if (atomic_dec_and_test(&ctx->refcount)) {
1128 if (ctx->parent_ctx)
1129 put_ctx(ctx->parent_ctx);
1130 if (ctx->task && ctx->task != TASK_TOMBSTONE)
1131 put_task_struct(ctx->task);
1132 call_rcu(&ctx->rcu_head, free_ctx);
1137 * Because of perf_event::ctx migration in sys_perf_event_open::move_group and
1138 * perf_pmu_migrate_context() we need some magic.
1140 * Those places that change perf_event::ctx will hold both
1141 * perf_event_ctx::mutex of the 'old' and 'new' ctx value.
1143 * Lock ordering is by mutex address. There are two other sites where
1144 * perf_event_context::mutex nests and those are:
1146 * - perf_event_exit_task_context() [ child , 0 ]
1147 * perf_event_exit_event()
1148 * put_event() [ parent, 1 ]
1150 * - perf_event_init_context() [ parent, 0 ]
1151 * inherit_task_group()
1154 * perf_event_alloc()
1156 * perf_try_init_event() [ child , 1 ]
1158 * While it appears there is an obvious deadlock here -- the parent and child
1159 * nesting levels are inverted between the two. This is in fact safe because
1160 * life-time rules separate them. That is an exiting task cannot fork, and a
1161 * spawning task cannot (yet) exit.
1163 * But remember that that these are parent<->child context relations, and
1164 * migration does not affect children, therefore these two orderings should not
1167 * The change in perf_event::ctx does not affect children (as claimed above)
1168 * because the sys_perf_event_open() case will install a new event and break
1169 * the ctx parent<->child relation, and perf_pmu_migrate_context() is only
1170 * concerned with cpuctx and that doesn't have children.
1172 * The places that change perf_event::ctx will issue:
1174 * perf_remove_from_context();
1175 * synchronize_rcu();
1176 * perf_install_in_context();
1178 * to affect the change. The remove_from_context() + synchronize_rcu() should
1179 * quiesce the event, after which we can install it in the new location. This
1180 * means that only external vectors (perf_fops, prctl) can perturb the event
1181 * while in transit. Therefore all such accessors should also acquire
1182 * perf_event_context::mutex to serialize against this.
1184 * However; because event->ctx can change while we're waiting to acquire
1185 * ctx->mutex we must be careful and use the below perf_event_ctx_lock()
1190 * task_struct::perf_event_mutex
1191 * perf_event_context::mutex
1192 * perf_event::child_mutex;
1193 * perf_event_context::lock
1194 * perf_event::mmap_mutex
1197 static struct perf_event_context *
1198 perf_event_ctx_lock_nested(struct perf_event *event, int nesting)
1200 struct perf_event_context *ctx;
1204 ctx = ACCESS_ONCE(event->ctx);
1205 if (!atomic_inc_not_zero(&ctx->refcount)) {
1211 mutex_lock_nested(&ctx->mutex, nesting);
1212 if (event->ctx != ctx) {
1213 mutex_unlock(&ctx->mutex);
1221 static inline struct perf_event_context *
1222 perf_event_ctx_lock(struct perf_event *event)
1224 return perf_event_ctx_lock_nested(event, 0);
1227 static void perf_event_ctx_unlock(struct perf_event *event,
1228 struct perf_event_context *ctx)
1230 mutex_unlock(&ctx->mutex);
1235 * This must be done under the ctx->lock, such as to serialize against
1236 * context_equiv(), therefore we cannot call put_ctx() since that might end up
1237 * calling scheduler related locks and ctx->lock nests inside those.
1239 static __must_check struct perf_event_context *
1240 unclone_ctx(struct perf_event_context *ctx)
1242 struct perf_event_context *parent_ctx = ctx->parent_ctx;
1244 lockdep_assert_held(&ctx->lock);
1247 ctx->parent_ctx = NULL;
1253 static u32 perf_event_pid(struct perf_event *event, struct task_struct *p)
1256 * only top level events have the pid namespace they were created in
1259 event = event->parent;
1261 return task_tgid_nr_ns(p, event->ns);
1264 static u32 perf_event_tid(struct perf_event *event, struct task_struct *p)
1267 * only top level events have the pid namespace they were created in
1270 event = event->parent;
1272 return task_pid_nr_ns(p, event->ns);
1276 * If we inherit events we want to return the parent event id
1279 static u64 primary_event_id(struct perf_event *event)
1284 id = event->parent->id;
1290 * Get the perf_event_context for a task and lock it.
1292 * This has to cope with with the fact that until it is locked,
1293 * the context could get moved to another task.
1295 static struct perf_event_context *
1296 perf_lock_task_context(struct task_struct *task, int ctxn, unsigned long *flags)
1298 struct perf_event_context *ctx;
1302 * One of the few rules of preemptible RCU is that one cannot do
1303 * rcu_read_unlock() while holding a scheduler (or nested) lock when
1304 * part of the read side critical section was irqs-enabled -- see
1305 * rcu_read_unlock_special().
1307 * Since ctx->lock nests under rq->lock we must ensure the entire read
1308 * side critical section has interrupts disabled.
1310 local_irq_save(*flags);
1312 ctx = rcu_dereference(task->perf_event_ctxp[ctxn]);
1315 * If this context is a clone of another, it might
1316 * get swapped for another underneath us by
1317 * perf_event_task_sched_out, though the
1318 * rcu_read_lock() protects us from any context
1319 * getting freed. Lock the context and check if it
1320 * got swapped before we could get the lock, and retry
1321 * if so. If we locked the right context, then it
1322 * can't get swapped on us any more.
1324 raw_spin_lock(&ctx->lock);
1325 if (ctx != rcu_dereference(task->perf_event_ctxp[ctxn])) {
1326 raw_spin_unlock(&ctx->lock);
1328 local_irq_restore(*flags);
1332 if (ctx->task == TASK_TOMBSTONE ||
1333 !atomic_inc_not_zero(&ctx->refcount)) {
1334 raw_spin_unlock(&ctx->lock);
1337 WARN_ON_ONCE(ctx->task != task);
1342 local_irq_restore(*flags);
1347 * Get the context for a task and increment its pin_count so it
1348 * can't get swapped to another task. This also increments its
1349 * reference count so that the context can't get freed.
1351 static struct perf_event_context *
1352 perf_pin_task_context(struct task_struct *task, int ctxn)
1354 struct perf_event_context *ctx;
1355 unsigned long flags;
1357 ctx = perf_lock_task_context(task, ctxn, &flags);
1360 raw_spin_unlock_irqrestore(&ctx->lock, flags);
1365 static void perf_unpin_context(struct perf_event_context *ctx)
1367 unsigned long flags;
1369 raw_spin_lock_irqsave(&ctx->lock, flags);
1371 raw_spin_unlock_irqrestore(&ctx->lock, flags);
1375 * Update the record of the current time in a context.
1377 static void update_context_time(struct perf_event_context *ctx)
1379 u64 now = perf_clock();
1381 ctx->time += now - ctx->timestamp;
1382 ctx->timestamp = now;
1385 static u64 perf_event_time(struct perf_event *event)
1387 struct perf_event_context *ctx = event->ctx;
1389 if (is_cgroup_event(event))
1390 return perf_cgroup_event_time(event);
1392 return ctx ? ctx->time : 0;
1396 * Update the total_time_enabled and total_time_running fields for a event.
1398 static void update_event_times(struct perf_event *event)
1400 struct perf_event_context *ctx = event->ctx;
1403 lockdep_assert_held(&ctx->lock);
1405 if (event->state < PERF_EVENT_STATE_INACTIVE ||
1406 event->group_leader->state < PERF_EVENT_STATE_INACTIVE)
1410 * in cgroup mode, time_enabled represents
1411 * the time the event was enabled AND active
1412 * tasks were in the monitored cgroup. This is
1413 * independent of the activity of the context as
1414 * there may be a mix of cgroup and non-cgroup events.
1416 * That is why we treat cgroup events differently
1419 if (is_cgroup_event(event))
1420 run_end = perf_cgroup_event_time(event);
1421 else if (ctx->is_active)
1422 run_end = ctx->time;
1424 run_end = event->tstamp_stopped;
1426 event->total_time_enabled = run_end - event->tstamp_enabled;
1428 if (event->state == PERF_EVENT_STATE_INACTIVE)
1429 run_end = event->tstamp_stopped;
1431 run_end = perf_event_time(event);
1433 event->total_time_running = run_end - event->tstamp_running;
1438 * Update total_time_enabled and total_time_running for all events in a group.
1440 static void update_group_times(struct perf_event *leader)
1442 struct perf_event *event;
1444 update_event_times(leader);
1445 list_for_each_entry(event, &leader->sibling_list, group_entry)
1446 update_event_times(event);
1449 static enum event_type_t get_event_type(struct perf_event *event)
1451 struct perf_event_context *ctx = event->ctx;
1452 enum event_type_t event_type;
1454 lockdep_assert_held(&ctx->lock);
1456 event_type = event->attr.pinned ? EVENT_PINNED : EVENT_FLEXIBLE;
1458 event_type |= EVENT_CPU;
1463 static struct list_head *
1464 ctx_group_list(struct perf_event *event, struct perf_event_context *ctx)
1466 if (event->attr.pinned)
1467 return &ctx->pinned_groups;
1469 return &ctx->flexible_groups;
1473 * Add a event from the lists for its context.
1474 * Must be called with ctx->mutex and ctx->lock held.
1477 list_add_event(struct perf_event *event, struct perf_event_context *ctx)
1479 lockdep_assert_held(&ctx->lock);
1481 WARN_ON_ONCE(event->attach_state & PERF_ATTACH_CONTEXT);
1482 event->attach_state |= PERF_ATTACH_CONTEXT;
1485 * If we're a stand alone event or group leader, we go to the context
1486 * list, group events are kept attached to the group so that
1487 * perf_group_detach can, at all times, locate all siblings.
1489 if (event->group_leader == event) {
1490 struct list_head *list;
1492 event->group_caps = event->event_caps;
1494 list = ctx_group_list(event, ctx);
1495 list_add_tail(&event->group_entry, list);
1498 list_update_cgroup_event(event, ctx, true);
1500 list_add_rcu(&event->event_entry, &ctx->event_list);
1502 if (event->attr.inherit_stat)
1509 * Initialize event state based on the perf_event_attr::disabled.
1511 static inline void perf_event__state_init(struct perf_event *event)
1513 event->state = event->attr.disabled ? PERF_EVENT_STATE_OFF :
1514 PERF_EVENT_STATE_INACTIVE;
1517 static void __perf_event_read_size(struct perf_event *event, int nr_siblings)
1519 int entry = sizeof(u64); /* value */
1523 if (event->attr.read_format & PERF_FORMAT_TOTAL_TIME_ENABLED)
1524 size += sizeof(u64);
1526 if (event->attr.read_format & PERF_FORMAT_TOTAL_TIME_RUNNING)
1527 size += sizeof(u64);
1529 if (event->attr.read_format & PERF_FORMAT_ID)
1530 entry += sizeof(u64);
1532 if (event->attr.read_format & PERF_FORMAT_GROUP) {
1534 size += sizeof(u64);
1538 event->read_size = size;
1541 static void __perf_event_header_size(struct perf_event *event, u64 sample_type)
1543 struct perf_sample_data *data;
1546 if (sample_type & PERF_SAMPLE_IP)
1547 size += sizeof(data->ip);
1549 if (sample_type & PERF_SAMPLE_ADDR)
1550 size += sizeof(data->addr);
1552 if (sample_type & PERF_SAMPLE_PERIOD)
1553 size += sizeof(data->period);
1555 if (sample_type & PERF_SAMPLE_WEIGHT)
1556 size += sizeof(data->weight);
1558 if (sample_type & PERF_SAMPLE_READ)
1559 size += event->read_size;
1561 if (sample_type & PERF_SAMPLE_DATA_SRC)
1562 size += sizeof(data->data_src.val);
1564 if (sample_type & PERF_SAMPLE_TRANSACTION)
1565 size += sizeof(data->txn);
1567 event->header_size = size;
1571 * Called at perf_event creation and when events are attached/detached from a
1574 static void perf_event__header_size(struct perf_event *event)
1576 __perf_event_read_size(event,
1577 event->group_leader->nr_siblings);
1578 __perf_event_header_size(event, event->attr.sample_type);
1581 static void perf_event__id_header_size(struct perf_event *event)
1583 struct perf_sample_data *data;
1584 u64 sample_type = event->attr.sample_type;
1587 if (sample_type & PERF_SAMPLE_TID)
1588 size += sizeof(data->tid_entry);
1590 if (sample_type & PERF_SAMPLE_TIME)
1591 size += sizeof(data->time);
1593 if (sample_type & PERF_SAMPLE_IDENTIFIER)
1594 size += sizeof(data->id);
1596 if (sample_type & PERF_SAMPLE_ID)
1597 size += sizeof(data->id);
1599 if (sample_type & PERF_SAMPLE_STREAM_ID)
1600 size += sizeof(data->stream_id);
1602 if (sample_type & PERF_SAMPLE_CPU)
1603 size += sizeof(data->cpu_entry);
1605 event->id_header_size = size;
1608 static bool perf_event_validate_size(struct perf_event *event)
1611 * The values computed here will be over-written when we actually
1614 __perf_event_read_size(event, event->group_leader->nr_siblings + 1);
1615 __perf_event_header_size(event, event->attr.sample_type & ~PERF_SAMPLE_READ);
1616 perf_event__id_header_size(event);
1619 * Sum the lot; should not exceed the 64k limit we have on records.
1620 * Conservative limit to allow for callchains and other variable fields.
1622 if (event->read_size + event->header_size +
1623 event->id_header_size + sizeof(struct perf_event_header) >= 16*1024)
1629 static void perf_group_attach(struct perf_event *event)
1631 struct perf_event *group_leader = event->group_leader, *pos;
1633 lockdep_assert_held(&event->ctx->lock);
1636 * We can have double attach due to group movement in perf_event_open.
1638 if (event->attach_state & PERF_ATTACH_GROUP)
1641 event->attach_state |= PERF_ATTACH_GROUP;
1643 if (group_leader == event)
1646 WARN_ON_ONCE(group_leader->ctx != event->ctx);
1648 group_leader->group_caps &= event->event_caps;
1650 list_add_tail(&event->group_entry, &group_leader->sibling_list);
1651 group_leader->nr_siblings++;
1653 perf_event__header_size(group_leader);
1655 list_for_each_entry(pos, &group_leader->sibling_list, group_entry)
1656 perf_event__header_size(pos);
1660 * Remove a event from the lists for its context.
1661 * Must be called with ctx->mutex and ctx->lock held.
1664 list_del_event(struct perf_event *event, struct perf_event_context *ctx)
1666 WARN_ON_ONCE(event->ctx != ctx);
1667 lockdep_assert_held(&ctx->lock);
1670 * We can have double detach due to exit/hot-unplug + close.
1672 if (!(event->attach_state & PERF_ATTACH_CONTEXT))
1675 event->attach_state &= ~PERF_ATTACH_CONTEXT;
1677 list_update_cgroup_event(event, ctx, false);
1680 if (event->attr.inherit_stat)
1683 list_del_rcu(&event->event_entry);
1685 if (event->group_leader == event)
1686 list_del_init(&event->group_entry);
1688 update_group_times(event);
1691 * If event was in error state, then keep it
1692 * that way, otherwise bogus counts will be
1693 * returned on read(). The only way to get out
1694 * of error state is by explicit re-enabling
1697 if (event->state > PERF_EVENT_STATE_OFF)
1698 event->state = PERF_EVENT_STATE_OFF;
1703 static void perf_group_detach(struct perf_event *event)
1705 struct perf_event *sibling, *tmp;
1706 struct list_head *list = NULL;
1708 lockdep_assert_held(&event->ctx->lock);
1711 * We can have double detach due to exit/hot-unplug + close.
1713 if (!(event->attach_state & PERF_ATTACH_GROUP))
1716 event->attach_state &= ~PERF_ATTACH_GROUP;
1719 * If this is a sibling, remove it from its group.
1721 if (event->group_leader != event) {
1722 list_del_init(&event->group_entry);
1723 event->group_leader->nr_siblings--;
1727 if (!list_empty(&event->group_entry))
1728 list = &event->group_entry;
1731 * If this was a group event with sibling events then
1732 * upgrade the siblings to singleton events by adding them
1733 * to whatever list we are on.
1735 list_for_each_entry_safe(sibling, tmp, &event->sibling_list, group_entry) {
1737 list_move_tail(&sibling->group_entry, list);
1738 sibling->group_leader = sibling;
1740 /* Inherit group flags from the previous leader */
1741 sibling->group_caps = event->group_caps;
1743 WARN_ON_ONCE(sibling->ctx != event->ctx);
1747 perf_event__header_size(event->group_leader);
1749 list_for_each_entry(tmp, &event->group_leader->sibling_list, group_entry)
1750 perf_event__header_size(tmp);
1753 static bool is_orphaned_event(struct perf_event *event)
1755 return event->state == PERF_EVENT_STATE_DEAD;
1758 static inline int __pmu_filter_match(struct perf_event *event)
1760 struct pmu *pmu = event->pmu;
1761 return pmu->filter_match ? pmu->filter_match(event) : 1;
1765 * Check whether we should attempt to schedule an event group based on
1766 * PMU-specific filtering. An event group can consist of HW and SW events,
1767 * potentially with a SW leader, so we must check all the filters, to
1768 * determine whether a group is schedulable:
1770 static inline int pmu_filter_match(struct perf_event *event)
1772 struct perf_event *child;
1774 if (!__pmu_filter_match(event))
1777 list_for_each_entry(child, &event->sibling_list, group_entry) {
1778 if (!__pmu_filter_match(child))
1786 event_filter_match(struct perf_event *event)
1788 return (event->cpu == -1 || event->cpu == smp_processor_id()) &&
1789 perf_cgroup_match(event) && pmu_filter_match(event);
1793 event_sched_out(struct perf_event *event,
1794 struct perf_cpu_context *cpuctx,
1795 struct perf_event_context *ctx)
1797 u64 tstamp = perf_event_time(event);
1800 WARN_ON_ONCE(event->ctx != ctx);
1801 lockdep_assert_held(&ctx->lock);
1804 * An event which could not be activated because of
1805 * filter mismatch still needs to have its timings
1806 * maintained, otherwise bogus information is return
1807 * via read() for time_enabled, time_running:
1809 if (event->state == PERF_EVENT_STATE_INACTIVE &&
1810 !event_filter_match(event)) {
1811 delta = tstamp - event->tstamp_stopped;
1812 event->tstamp_running += delta;
1813 event->tstamp_stopped = tstamp;
1816 if (event->state != PERF_EVENT_STATE_ACTIVE)
1819 perf_pmu_disable(event->pmu);
1821 event->tstamp_stopped = tstamp;
1822 event->pmu->del(event, 0);
1824 event->state = PERF_EVENT_STATE_INACTIVE;
1825 if (event->pending_disable) {
1826 event->pending_disable = 0;
1827 event->state = PERF_EVENT_STATE_OFF;
1830 if (!is_software_event(event))
1831 cpuctx->active_oncpu--;
1832 if (!--ctx->nr_active)
1833 perf_event_ctx_deactivate(ctx);
1834 if (event->attr.freq && event->attr.sample_freq)
1836 if (event->attr.exclusive || !cpuctx->active_oncpu)
1837 cpuctx->exclusive = 0;
1839 perf_pmu_enable(event->pmu);
1843 group_sched_out(struct perf_event *group_event,
1844 struct perf_cpu_context *cpuctx,
1845 struct perf_event_context *ctx)
1847 struct perf_event *event;
1848 int state = group_event->state;
1850 perf_pmu_disable(ctx->pmu);
1852 event_sched_out(group_event, cpuctx, ctx);
1855 * Schedule out siblings (if any):
1857 list_for_each_entry(event, &group_event->sibling_list, group_entry)
1858 event_sched_out(event, cpuctx, ctx);
1860 perf_pmu_enable(ctx->pmu);
1862 if (state == PERF_EVENT_STATE_ACTIVE && group_event->attr.exclusive)
1863 cpuctx->exclusive = 0;
1866 #define DETACH_GROUP 0x01UL
1869 * Cross CPU call to remove a performance event
1871 * We disable the event on the hardware level first. After that we
1872 * remove it from the context list.
1875 __perf_remove_from_context(struct perf_event *event,
1876 struct perf_cpu_context *cpuctx,
1877 struct perf_event_context *ctx,
1880 unsigned long flags = (unsigned long)info;
1882 event_sched_out(event, cpuctx, ctx);
1883 if (flags & DETACH_GROUP)
1884 perf_group_detach(event);
1885 list_del_event(event, ctx);
1887 if (!ctx->nr_events && ctx->is_active) {
1890 WARN_ON_ONCE(cpuctx->task_ctx != ctx);
1891 cpuctx->task_ctx = NULL;
1897 * Remove the event from a task's (or a CPU's) list of events.
1899 * If event->ctx is a cloned context, callers must make sure that
1900 * every task struct that event->ctx->task could possibly point to
1901 * remains valid. This is OK when called from perf_release since
1902 * that only calls us on the top-level context, which can't be a clone.
1903 * When called from perf_event_exit_task, it's OK because the
1904 * context has been detached from its task.
1906 static void perf_remove_from_context(struct perf_event *event, unsigned long flags)
1908 struct perf_event_context *ctx = event->ctx;
1910 lockdep_assert_held(&ctx->mutex);
1912 event_function_call(event, __perf_remove_from_context, (void *)flags);
1915 * The above event_function_call() can NO-OP when it hits
1916 * TASK_TOMBSTONE. In that case we must already have been detached
1917 * from the context (by perf_event_exit_event()) but the grouping
1918 * might still be in-tact.
1920 WARN_ON_ONCE(event->attach_state & PERF_ATTACH_CONTEXT);
1921 if ((flags & DETACH_GROUP) &&
1922 (event->attach_state & PERF_ATTACH_GROUP)) {
1924 * Since in that case we cannot possibly be scheduled, simply
1927 raw_spin_lock_irq(&ctx->lock);
1928 perf_group_detach(event);
1929 raw_spin_unlock_irq(&ctx->lock);
1934 * Cross CPU call to disable a performance event
1936 static void __perf_event_disable(struct perf_event *event,
1937 struct perf_cpu_context *cpuctx,
1938 struct perf_event_context *ctx,
1941 if (event->state < PERF_EVENT_STATE_INACTIVE)
1944 update_context_time(ctx);
1945 update_cgrp_time_from_event(event);
1946 update_group_times(event);
1947 if (event == event->group_leader)
1948 group_sched_out(event, cpuctx, ctx);
1950 event_sched_out(event, cpuctx, ctx);
1951 event->state = PERF_EVENT_STATE_OFF;
1957 * If event->ctx is a cloned context, callers must make sure that
1958 * every task struct that event->ctx->task could possibly point to
1959 * remains valid. This condition is satisifed when called through
1960 * perf_event_for_each_child or perf_event_for_each because they
1961 * hold the top-level event's child_mutex, so any descendant that
1962 * goes to exit will block in perf_event_exit_event().
1964 * When called from perf_pending_event it's OK because event->ctx
1965 * is the current context on this CPU and preemption is disabled,
1966 * hence we can't get into perf_event_task_sched_out for this context.
1968 static void _perf_event_disable(struct perf_event *event)
1970 struct perf_event_context *ctx = event->ctx;
1972 raw_spin_lock_irq(&ctx->lock);
1973 if (event->state <= PERF_EVENT_STATE_OFF) {
1974 raw_spin_unlock_irq(&ctx->lock);
1977 raw_spin_unlock_irq(&ctx->lock);
1979 event_function_call(event, __perf_event_disable, NULL);
1982 void perf_event_disable_local(struct perf_event *event)
1984 event_function_local(event, __perf_event_disable, NULL);
1988 * Strictly speaking kernel users cannot create groups and therefore this
1989 * interface does not need the perf_event_ctx_lock() magic.
1991 void perf_event_disable(struct perf_event *event)
1993 struct perf_event_context *ctx;
1995 ctx = perf_event_ctx_lock(event);
1996 _perf_event_disable(event);
1997 perf_event_ctx_unlock(event, ctx);
1999 EXPORT_SYMBOL_GPL(perf_event_disable);
2001 void perf_event_disable_inatomic(struct perf_event *event)
2003 event->pending_disable = 1;
2004 irq_work_queue(&event->pending);
2007 static void perf_set_shadow_time(struct perf_event *event,
2008 struct perf_event_context *ctx,
2012 * use the correct time source for the time snapshot
2014 * We could get by without this by leveraging the
2015 * fact that to get to this function, the caller
2016 * has most likely already called update_context_time()
2017 * and update_cgrp_time_xx() and thus both timestamp
2018 * are identical (or very close). Given that tstamp is,
2019 * already adjusted for cgroup, we could say that:
2020 * tstamp - ctx->timestamp
2022 * tstamp - cgrp->timestamp.
2024 * Then, in perf_output_read(), the calculation would
2025 * work with no changes because:
2026 * - event is guaranteed scheduled in
2027 * - no scheduled out in between
2028 * - thus the timestamp would be the same
2030 * But this is a bit hairy.
2032 * So instead, we have an explicit cgroup call to remain
2033 * within the time time source all along. We believe it
2034 * is cleaner and simpler to understand.
2036 if (is_cgroup_event(event))
2037 perf_cgroup_set_shadow_time(event, tstamp);
2039 event->shadow_ctx_time = tstamp - ctx->timestamp;
2042 #define MAX_INTERRUPTS (~0ULL)
2044 static void perf_log_throttle(struct perf_event *event, int enable);
2045 static void perf_log_itrace_start(struct perf_event *event);
2048 event_sched_in(struct perf_event *event,
2049 struct perf_cpu_context *cpuctx,
2050 struct perf_event_context *ctx)
2052 u64 tstamp = perf_event_time(event);
2055 lockdep_assert_held(&ctx->lock);
2057 if (event->state <= PERF_EVENT_STATE_OFF)
2060 WRITE_ONCE(event->oncpu, smp_processor_id());
2062 * Order event::oncpu write to happen before the ACTIVE state
2066 WRITE_ONCE(event->state, PERF_EVENT_STATE_ACTIVE);
2069 * Unthrottle events, since we scheduled we might have missed several
2070 * ticks already, also for a heavily scheduling task there is little
2071 * guarantee it'll get a tick in a timely manner.
2073 if (unlikely(event->hw.interrupts == MAX_INTERRUPTS)) {
2074 perf_log_throttle(event, 1);
2075 event->hw.interrupts = 0;
2079 * The new state must be visible before we turn it on in the hardware:
2083 perf_pmu_disable(event->pmu);
2085 perf_set_shadow_time(event, ctx, tstamp);
2087 perf_log_itrace_start(event);
2089 if (event->pmu->add(event, PERF_EF_START)) {
2090 event->state = PERF_EVENT_STATE_INACTIVE;
2096 event->tstamp_running += tstamp - event->tstamp_stopped;
2098 if (!is_software_event(event))
2099 cpuctx->active_oncpu++;
2100 if (!ctx->nr_active++)
2101 perf_event_ctx_activate(ctx);
2102 if (event->attr.freq && event->attr.sample_freq)
2105 if (event->attr.exclusive)
2106 cpuctx->exclusive = 1;
2109 perf_pmu_enable(event->pmu);
2115 group_sched_in(struct perf_event *group_event,
2116 struct perf_cpu_context *cpuctx,
2117 struct perf_event_context *ctx)
2119 struct perf_event *event, *partial_group = NULL;
2120 struct pmu *pmu = ctx->pmu;
2121 u64 now = ctx->time;
2122 bool simulate = false;
2124 if (group_event->state == PERF_EVENT_STATE_OFF)
2127 pmu->start_txn(pmu, PERF_PMU_TXN_ADD);
2129 if (event_sched_in(group_event, cpuctx, ctx)) {
2130 pmu->cancel_txn(pmu);
2131 perf_mux_hrtimer_restart(cpuctx);
2136 * Schedule in siblings as one group (if any):
2138 list_for_each_entry(event, &group_event->sibling_list, group_entry) {
2139 if (event_sched_in(event, cpuctx, ctx)) {
2140 partial_group = event;
2145 if (!pmu->commit_txn(pmu))
2150 * Groups can be scheduled in as one unit only, so undo any
2151 * partial group before returning:
2152 * The events up to the failed event are scheduled out normally,
2153 * tstamp_stopped will be updated.
2155 * The failed events and the remaining siblings need to have
2156 * their timings updated as if they had gone thru event_sched_in()
2157 * and event_sched_out(). This is required to get consistent timings
2158 * across the group. This also takes care of the case where the group
2159 * could never be scheduled by ensuring tstamp_stopped is set to mark
2160 * the time the event was actually stopped, such that time delta
2161 * calculation in update_event_times() is correct.
2163 list_for_each_entry(event, &group_event->sibling_list, group_entry) {
2164 if (event == partial_group)
2168 event->tstamp_running += now - event->tstamp_stopped;
2169 event->tstamp_stopped = now;
2171 event_sched_out(event, cpuctx, ctx);
2174 event_sched_out(group_event, cpuctx, ctx);
2176 pmu->cancel_txn(pmu);
2178 perf_mux_hrtimer_restart(cpuctx);
2184 * Work out whether we can put this event group on the CPU now.
2186 static int group_can_go_on(struct perf_event *event,
2187 struct perf_cpu_context *cpuctx,
2191 * Groups consisting entirely of software events can always go on.
2193 if (event->group_caps & PERF_EV_CAP_SOFTWARE)
2196 * If an exclusive group is already on, no other hardware
2199 if (cpuctx->exclusive)
2202 * If this group is exclusive and there are already
2203 * events on the CPU, it can't go on.
2205 if (event->attr.exclusive && cpuctx->active_oncpu)
2208 * Otherwise, try to add it if all previous groups were able
2214 static void add_event_to_ctx(struct perf_event *event,
2215 struct perf_event_context *ctx)
2217 u64 tstamp = perf_event_time(event);
2219 list_add_event(event, ctx);
2220 perf_group_attach(event);
2221 event->tstamp_enabled = tstamp;
2222 event->tstamp_running = tstamp;
2223 event->tstamp_stopped = tstamp;
2226 static void ctx_sched_out(struct perf_event_context *ctx,
2227 struct perf_cpu_context *cpuctx,
2228 enum event_type_t event_type);
2230 ctx_sched_in(struct perf_event_context *ctx,
2231 struct perf_cpu_context *cpuctx,
2232 enum event_type_t event_type,
2233 struct task_struct *task);
2235 static void task_ctx_sched_out(struct perf_cpu_context *cpuctx,
2236 struct perf_event_context *ctx,
2237 enum event_type_t event_type)
2239 if (!cpuctx->task_ctx)
2242 if (WARN_ON_ONCE(ctx != cpuctx->task_ctx))
2245 ctx_sched_out(ctx, cpuctx, event_type);
2248 static void perf_event_sched_in(struct perf_cpu_context *cpuctx,
2249 struct perf_event_context *ctx,
2250 struct task_struct *task)
2252 cpu_ctx_sched_in(cpuctx, EVENT_PINNED, task);
2254 ctx_sched_in(ctx, cpuctx, EVENT_PINNED, task);
2255 cpu_ctx_sched_in(cpuctx, EVENT_FLEXIBLE, task);
2257 ctx_sched_in(ctx, cpuctx, EVENT_FLEXIBLE, task);
2261 * We want to maintain the following priority of scheduling:
2262 * - CPU pinned (EVENT_CPU | EVENT_PINNED)
2263 * - task pinned (EVENT_PINNED)
2264 * - CPU flexible (EVENT_CPU | EVENT_FLEXIBLE)
2265 * - task flexible (EVENT_FLEXIBLE).
2267 * In order to avoid unscheduling and scheduling back in everything every
2268 * time an event is added, only do it for the groups of equal priority and
2271 * This can be called after a batch operation on task events, in which case
2272 * event_type is a bit mask of the types of events involved. For CPU events,
2273 * event_type is only either EVENT_PINNED or EVENT_FLEXIBLE.
2275 static void ctx_resched(struct perf_cpu_context *cpuctx,
2276 struct perf_event_context *task_ctx,
2277 enum event_type_t event_type)
2279 enum event_type_t ctx_event_type = event_type & EVENT_ALL;
2280 bool cpu_event = !!(event_type & EVENT_CPU);
2283 * If pinned groups are involved, flexible groups also need to be
2286 if (event_type & EVENT_PINNED)
2287 event_type |= EVENT_FLEXIBLE;
2289 perf_pmu_disable(cpuctx->ctx.pmu);
2291 task_ctx_sched_out(cpuctx, task_ctx, event_type);
2294 * Decide which cpu ctx groups to schedule out based on the types
2295 * of events that caused rescheduling:
2296 * - EVENT_CPU: schedule out corresponding groups;
2297 * - EVENT_PINNED task events: schedule out EVENT_FLEXIBLE groups;
2298 * - otherwise, do nothing more.
2301 cpu_ctx_sched_out(cpuctx, ctx_event_type);
2302 else if (ctx_event_type & EVENT_PINNED)
2303 cpu_ctx_sched_out(cpuctx, EVENT_FLEXIBLE);
2305 perf_event_sched_in(cpuctx, task_ctx, current);
2306 perf_pmu_enable(cpuctx->ctx.pmu);
2310 * Cross CPU call to install and enable a performance event
2312 * Very similar to remote_function() + event_function() but cannot assume that
2313 * things like ctx->is_active and cpuctx->task_ctx are set.
2315 static int __perf_install_in_context(void *info)
2317 struct perf_event *event = info;
2318 struct perf_event_context *ctx = event->ctx;
2319 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
2320 struct perf_event_context *task_ctx = cpuctx->task_ctx;
2321 bool reprogram = true;
2324 raw_spin_lock(&cpuctx->ctx.lock);
2326 raw_spin_lock(&ctx->lock);
2329 reprogram = (ctx->task == current);
2332 * If the task is running, it must be running on this CPU,
2333 * otherwise we cannot reprogram things.
2335 * If its not running, we don't care, ctx->lock will
2336 * serialize against it becoming runnable.
2338 if (task_curr(ctx->task) && !reprogram) {
2343 WARN_ON_ONCE(reprogram && cpuctx->task_ctx && cpuctx->task_ctx != ctx);
2344 } else if (task_ctx) {
2345 raw_spin_lock(&task_ctx->lock);
2349 ctx_sched_out(ctx, cpuctx, EVENT_TIME);
2350 add_event_to_ctx(event, ctx);
2351 ctx_resched(cpuctx, task_ctx, get_event_type(event));
2353 add_event_to_ctx(event, ctx);
2357 perf_ctx_unlock(cpuctx, task_ctx);
2363 * Attach a performance event to a context.
2365 * Very similar to event_function_call, see comment there.
2368 perf_install_in_context(struct perf_event_context *ctx,
2369 struct perf_event *event,
2372 struct task_struct *task = READ_ONCE(ctx->task);
2374 lockdep_assert_held(&ctx->mutex);
2376 if (event->cpu != -1)
2380 * Ensures that if we can observe event->ctx, both the event and ctx
2381 * will be 'complete'. See perf_iterate_sb_cpu().
2383 smp_store_release(&event->ctx, ctx);
2386 cpu_function_call(cpu, __perf_install_in_context, event);
2391 * Should not happen, we validate the ctx is still alive before calling.
2393 if (WARN_ON_ONCE(task == TASK_TOMBSTONE))
2397 * Installing events is tricky because we cannot rely on ctx->is_active
2398 * to be set in case this is the nr_events 0 -> 1 transition.
2400 * Instead we use task_curr(), which tells us if the task is running.
2401 * However, since we use task_curr() outside of rq::lock, we can race
2402 * against the actual state. This means the result can be wrong.
2404 * If we get a false positive, we retry, this is harmless.
2406 * If we get a false negative, things are complicated. If we are after
2407 * perf_event_context_sched_in() ctx::lock will serialize us, and the
2408 * value must be correct. If we're before, it doesn't matter since
2409 * perf_event_context_sched_in() will program the counter.
2411 * However, this hinges on the remote context switch having observed
2412 * our task->perf_event_ctxp[] store, such that it will in fact take
2413 * ctx::lock in perf_event_context_sched_in().
2415 * We do this by task_function_call(), if the IPI fails to hit the task
2416 * we know any future context switch of task must see the
2417 * perf_event_ctpx[] store.
2421 * This smp_mb() orders the task->perf_event_ctxp[] store with the
2422 * task_cpu() load, such that if the IPI then does not find the task
2423 * running, a future context switch of that task must observe the
2428 if (!task_function_call(task, __perf_install_in_context, event))
2431 raw_spin_lock_irq(&ctx->lock);
2433 if (WARN_ON_ONCE(task == TASK_TOMBSTONE)) {
2435 * Cannot happen because we already checked above (which also
2436 * cannot happen), and we hold ctx->mutex, which serializes us
2437 * against perf_event_exit_task_context().
2439 raw_spin_unlock_irq(&ctx->lock);
2443 * If the task is not running, ctx->lock will avoid it becoming so,
2444 * thus we can safely install the event.
2446 if (task_curr(task)) {
2447 raw_spin_unlock_irq(&ctx->lock);
2450 add_event_to_ctx(event, ctx);
2451 raw_spin_unlock_irq(&ctx->lock);
2455 * Put a event into inactive state and update time fields.
2456 * Enabling the leader of a group effectively enables all
2457 * the group members that aren't explicitly disabled, so we
2458 * have to update their ->tstamp_enabled also.
2459 * Note: this works for group members as well as group leaders
2460 * since the non-leader members' sibling_lists will be empty.
2462 static void __perf_event_mark_enabled(struct perf_event *event)
2464 struct perf_event *sub;
2465 u64 tstamp = perf_event_time(event);
2467 event->state = PERF_EVENT_STATE_INACTIVE;
2468 event->tstamp_enabled = tstamp - event->total_time_enabled;
2469 list_for_each_entry(sub, &event->sibling_list, group_entry) {
2470 if (sub->state >= PERF_EVENT_STATE_INACTIVE)
2471 sub->tstamp_enabled = tstamp - sub->total_time_enabled;
2476 * Cross CPU call to enable a performance event
2478 static void __perf_event_enable(struct perf_event *event,
2479 struct perf_cpu_context *cpuctx,
2480 struct perf_event_context *ctx,
2483 struct perf_event *leader = event->group_leader;
2484 struct perf_event_context *task_ctx;
2486 if (event->state >= PERF_EVENT_STATE_INACTIVE ||
2487 event->state <= PERF_EVENT_STATE_ERROR)
2491 ctx_sched_out(ctx, cpuctx, EVENT_TIME);
2493 __perf_event_mark_enabled(event);
2495 if (!ctx->is_active)
2498 if (!event_filter_match(event)) {
2499 if (is_cgroup_event(event))
2500 perf_cgroup_defer_enabled(event);
2501 ctx_sched_in(ctx, cpuctx, EVENT_TIME, current);
2506 * If the event is in a group and isn't the group leader,
2507 * then don't put it on unless the group is on.
2509 if (leader != event && leader->state != PERF_EVENT_STATE_ACTIVE) {
2510 ctx_sched_in(ctx, cpuctx, EVENT_TIME, current);
2514 task_ctx = cpuctx->task_ctx;
2516 WARN_ON_ONCE(task_ctx != ctx);
2518 ctx_resched(cpuctx, task_ctx, get_event_type(event));
2524 * If event->ctx is a cloned context, callers must make sure that
2525 * every task struct that event->ctx->task could possibly point to
2526 * remains valid. This condition is satisfied when called through
2527 * perf_event_for_each_child or perf_event_for_each as described
2528 * for perf_event_disable.
2530 static void _perf_event_enable(struct perf_event *event)
2532 struct perf_event_context *ctx = event->ctx;
2534 raw_spin_lock_irq(&ctx->lock);
2535 if (event->state >= PERF_EVENT_STATE_INACTIVE ||
2536 event->state < PERF_EVENT_STATE_ERROR) {
2537 raw_spin_unlock_irq(&ctx->lock);
2542 * If the event is in error state, clear that first.
2544 * That way, if we see the event in error state below, we know that it
2545 * has gone back into error state, as distinct from the task having
2546 * been scheduled away before the cross-call arrived.
2548 if (event->state == PERF_EVENT_STATE_ERROR)
2549 event->state = PERF_EVENT_STATE_OFF;
2550 raw_spin_unlock_irq(&ctx->lock);
2552 event_function_call(event, __perf_event_enable, NULL);
2556 * See perf_event_disable();
2558 void perf_event_enable(struct perf_event *event)
2560 struct perf_event_context *ctx;
2562 ctx = perf_event_ctx_lock(event);
2563 _perf_event_enable(event);
2564 perf_event_ctx_unlock(event, ctx);
2566 EXPORT_SYMBOL_GPL(perf_event_enable);
2568 struct stop_event_data {
2569 struct perf_event *event;
2570 unsigned int restart;
2573 static int __perf_event_stop(void *info)
2575 struct stop_event_data *sd = info;
2576 struct perf_event *event = sd->event;
2578 /* if it's already INACTIVE, do nothing */
2579 if (READ_ONCE(event->state) != PERF_EVENT_STATE_ACTIVE)
2582 /* matches smp_wmb() in event_sched_in() */
2586 * There is a window with interrupts enabled before we get here,
2587 * so we need to check again lest we try to stop another CPU's event.
2589 if (READ_ONCE(event->oncpu) != smp_processor_id())
2592 event->pmu->stop(event, PERF_EF_UPDATE);
2595 * May race with the actual stop (through perf_pmu_output_stop()),
2596 * but it is only used for events with AUX ring buffer, and such
2597 * events will refuse to restart because of rb::aux_mmap_count==0,
2598 * see comments in perf_aux_output_begin().
2600 * Since this is happening on a event-local CPU, no trace is lost
2604 event->pmu->start(event, 0);
2609 static int perf_event_stop(struct perf_event *event, int restart)
2611 struct stop_event_data sd = {
2618 if (READ_ONCE(event->state) != PERF_EVENT_STATE_ACTIVE)
2621 /* matches smp_wmb() in event_sched_in() */
2625 * We only want to restart ACTIVE events, so if the event goes
2626 * inactive here (event->oncpu==-1), there's nothing more to do;
2627 * fall through with ret==-ENXIO.
2629 ret = cpu_function_call(READ_ONCE(event->oncpu),
2630 __perf_event_stop, &sd);
2631 } while (ret == -EAGAIN);
2637 * In order to contain the amount of racy and tricky in the address filter
2638 * configuration management, it is a two part process:
2640 * (p1) when userspace mappings change as a result of (1) or (2) or (3) below,
2641 * we update the addresses of corresponding vmas in
2642 * event::addr_filters_offs array and bump the event::addr_filters_gen;
2643 * (p2) when an event is scheduled in (pmu::add), it calls
2644 * perf_event_addr_filters_sync() which calls pmu::addr_filters_sync()
2645 * if the generation has changed since the previous call.
2647 * If (p1) happens while the event is active, we restart it to force (p2).
2649 * (1) perf_addr_filters_apply(): adjusting filters' offsets based on
2650 * pre-existing mappings, called once when new filters arrive via SET_FILTER
2652 * (2) perf_addr_filters_adjust(): adjusting filters' offsets based on newly
2653 * registered mapping, called for every new mmap(), with mm::mmap_sem down
2655 * (3) perf_event_addr_filters_exec(): clearing filters' offsets in the process
2658 void perf_event_addr_filters_sync(struct perf_event *event)
2660 struct perf_addr_filters_head *ifh = perf_event_addr_filters(event);
2662 if (!has_addr_filter(event))
2665 raw_spin_lock(&ifh->lock);
2666 if (event->addr_filters_gen != event->hw.addr_filters_gen) {
2667 event->pmu->addr_filters_sync(event);
2668 event->hw.addr_filters_gen = event->addr_filters_gen;
2670 raw_spin_unlock(&ifh->lock);
2672 EXPORT_SYMBOL_GPL(perf_event_addr_filters_sync);
2674 static int _perf_event_refresh(struct perf_event *event, int refresh)
2677 * not supported on inherited events
2679 if (event->attr.inherit || !is_sampling_event(event))
2682 atomic_add(refresh, &event->event_limit);
2683 _perf_event_enable(event);
2689 * See perf_event_disable()
2691 int perf_event_refresh(struct perf_event *event, int refresh)
2693 struct perf_event_context *ctx;
2696 ctx = perf_event_ctx_lock(event);
2697 ret = _perf_event_refresh(event, refresh);
2698 perf_event_ctx_unlock(event, ctx);
2702 EXPORT_SYMBOL_GPL(perf_event_refresh);
2704 static void ctx_sched_out(struct perf_event_context *ctx,
2705 struct perf_cpu_context *cpuctx,
2706 enum event_type_t event_type)
2708 int is_active = ctx->is_active;
2709 struct perf_event *event;
2711 lockdep_assert_held(&ctx->lock);
2713 if (likely(!ctx->nr_events)) {
2715 * See __perf_remove_from_context().
2717 WARN_ON_ONCE(ctx->is_active);
2719 WARN_ON_ONCE(cpuctx->task_ctx);
2723 ctx->is_active &= ~event_type;
2724 if (!(ctx->is_active & EVENT_ALL))
2728 WARN_ON_ONCE(cpuctx->task_ctx != ctx);
2729 if (!ctx->is_active)
2730 cpuctx->task_ctx = NULL;
2734 * Always update time if it was set; not only when it changes.
2735 * Otherwise we can 'forget' to update time for any but the last
2736 * context we sched out. For example:
2738 * ctx_sched_out(.event_type = EVENT_FLEXIBLE)
2739 * ctx_sched_out(.event_type = EVENT_PINNED)
2741 * would only update time for the pinned events.
2743 if (is_active & EVENT_TIME) {
2744 /* update (and stop) ctx time */
2745 update_context_time(ctx);
2746 update_cgrp_time_from_cpuctx(cpuctx);
2749 is_active ^= ctx->is_active; /* changed bits */
2751 if (!ctx->nr_active || !(is_active & EVENT_ALL))
2754 perf_pmu_disable(ctx->pmu);
2755 if (is_active & EVENT_PINNED) {
2756 list_for_each_entry(event, &ctx->pinned_groups, group_entry)
2757 group_sched_out(event, cpuctx, ctx);
2760 if (is_active & EVENT_FLEXIBLE) {
2761 list_for_each_entry(event, &ctx->flexible_groups, group_entry)
2762 group_sched_out(event, cpuctx, ctx);
2764 perf_pmu_enable(ctx->pmu);
2768 * Test whether two contexts are equivalent, i.e. whether they have both been
2769 * cloned from the same version of the same context.
2771 * Equivalence is measured using a generation number in the context that is
2772 * incremented on each modification to it; see unclone_ctx(), list_add_event()
2773 * and list_del_event().
2775 static int context_equiv(struct perf_event_context *ctx1,
2776 struct perf_event_context *ctx2)
2778 lockdep_assert_held(&ctx1->lock);
2779 lockdep_assert_held(&ctx2->lock);
2781 /* Pinning disables the swap optimization */
2782 if (ctx1->pin_count || ctx2->pin_count)
2785 /* If ctx1 is the parent of ctx2 */
2786 if (ctx1 == ctx2->parent_ctx && ctx1->generation == ctx2->parent_gen)
2789 /* If ctx2 is the parent of ctx1 */
2790 if (ctx1->parent_ctx == ctx2 && ctx1->parent_gen == ctx2->generation)
2794 * If ctx1 and ctx2 have the same parent; we flatten the parent
2795 * hierarchy, see perf_event_init_context().
2797 if (ctx1->parent_ctx && ctx1->parent_ctx == ctx2->parent_ctx &&
2798 ctx1->parent_gen == ctx2->parent_gen)
2805 static void __perf_event_sync_stat(struct perf_event *event,
2806 struct perf_event *next_event)
2810 if (!event->attr.inherit_stat)
2814 * Update the event value, we cannot use perf_event_read()
2815 * because we're in the middle of a context switch and have IRQs
2816 * disabled, which upsets smp_call_function_single(), however
2817 * we know the event must be on the current CPU, therefore we
2818 * don't need to use it.
2820 switch (event->state) {
2821 case PERF_EVENT_STATE_ACTIVE:
2822 event->pmu->read(event);
2825 case PERF_EVENT_STATE_INACTIVE:
2826 update_event_times(event);
2834 * In order to keep per-task stats reliable we need to flip the event
2835 * values when we flip the contexts.
2837 value = local64_read(&next_event->count);
2838 value = local64_xchg(&event->count, value);
2839 local64_set(&next_event->count, value);
2841 swap(event->total_time_enabled, next_event->total_time_enabled);
2842 swap(event->total_time_running, next_event->total_time_running);
2845 * Since we swizzled the values, update the user visible data too.
2847 perf_event_update_userpage(event);
2848 perf_event_update_userpage(next_event);
2851 static void perf_event_sync_stat(struct perf_event_context *ctx,
2852 struct perf_event_context *next_ctx)
2854 struct perf_event *event, *next_event;
2859 update_context_time(ctx);
2861 event = list_first_entry(&ctx->event_list,
2862 struct perf_event, event_entry);
2864 next_event = list_first_entry(&next_ctx->event_list,
2865 struct perf_event, event_entry);
2867 while (&event->event_entry != &ctx->event_list &&
2868 &next_event->event_entry != &next_ctx->event_list) {
2870 __perf_event_sync_stat(event, next_event);
2872 event = list_next_entry(event, event_entry);
2873 next_event = list_next_entry(next_event, event_entry);
2877 static void perf_event_context_sched_out(struct task_struct *task, int ctxn,
2878 struct task_struct *next)
2880 struct perf_event_context *ctx = task->perf_event_ctxp[ctxn];
2881 struct perf_event_context *next_ctx;
2882 struct perf_event_context *parent, *next_parent;
2883 struct perf_cpu_context *cpuctx;
2889 cpuctx = __get_cpu_context(ctx);
2890 if (!cpuctx->task_ctx)
2894 next_ctx = next->perf_event_ctxp[ctxn];
2898 parent = rcu_dereference(ctx->parent_ctx);
2899 next_parent = rcu_dereference(next_ctx->parent_ctx);
2901 /* If neither context have a parent context; they cannot be clones. */
2902 if (!parent && !next_parent)
2905 if (next_parent == ctx || next_ctx == parent || next_parent == parent) {
2907 * Looks like the two contexts are clones, so we might be
2908 * able to optimize the context switch. We lock both
2909 * contexts and check that they are clones under the
2910 * lock (including re-checking that neither has been
2911 * uncloned in the meantime). It doesn't matter which
2912 * order we take the locks because no other cpu could
2913 * be trying to lock both of these tasks.
2915 raw_spin_lock(&ctx->lock);
2916 raw_spin_lock_nested(&next_ctx->lock, SINGLE_DEPTH_NESTING);
2917 if (context_equiv(ctx, next_ctx)) {
2918 WRITE_ONCE(ctx->task, next);
2919 WRITE_ONCE(next_ctx->task, task);
2921 swap(ctx->task_ctx_data, next_ctx->task_ctx_data);
2924 * RCU_INIT_POINTER here is safe because we've not
2925 * modified the ctx and the above modification of
2926 * ctx->task and ctx->task_ctx_data are immaterial
2927 * since those values are always verified under
2928 * ctx->lock which we're now holding.
2930 RCU_INIT_POINTER(task->perf_event_ctxp[ctxn], next_ctx);
2931 RCU_INIT_POINTER(next->perf_event_ctxp[ctxn], ctx);
2935 perf_event_sync_stat(ctx, next_ctx);
2937 raw_spin_unlock(&next_ctx->lock);
2938 raw_spin_unlock(&ctx->lock);
2944 raw_spin_lock(&ctx->lock);
2945 task_ctx_sched_out(cpuctx, ctx, EVENT_ALL);
2946 raw_spin_unlock(&ctx->lock);
2950 static DEFINE_PER_CPU(struct list_head, sched_cb_list);
2952 void perf_sched_cb_dec(struct pmu *pmu)
2954 struct perf_cpu_context *cpuctx = this_cpu_ptr(pmu->pmu_cpu_context);
2956 this_cpu_dec(perf_sched_cb_usages);
2958 if (!--cpuctx->sched_cb_usage)
2959 list_del(&cpuctx->sched_cb_entry);
2963 void perf_sched_cb_inc(struct pmu *pmu)
2965 struct perf_cpu_context *cpuctx = this_cpu_ptr(pmu->pmu_cpu_context);
2967 if (!cpuctx->sched_cb_usage++)
2968 list_add(&cpuctx->sched_cb_entry, this_cpu_ptr(&sched_cb_list));
2970 this_cpu_inc(perf_sched_cb_usages);
2974 * This function provides the context switch callback to the lower code
2975 * layer. It is invoked ONLY when the context switch callback is enabled.
2977 * This callback is relevant even to per-cpu events; for example multi event
2978 * PEBS requires this to provide PID/TID information. This requires we flush
2979 * all queued PEBS records before we context switch to a new task.
2981 static void perf_pmu_sched_task(struct task_struct *prev,
2982 struct task_struct *next,
2985 struct perf_cpu_context *cpuctx;
2991 list_for_each_entry(cpuctx, this_cpu_ptr(&sched_cb_list), sched_cb_entry) {
2992 pmu = cpuctx->ctx.pmu; /* software PMUs will not have sched_task */
2994 if (WARN_ON_ONCE(!pmu->sched_task))
2997 perf_ctx_lock(cpuctx, cpuctx->task_ctx);
2998 perf_pmu_disable(pmu);
3000 pmu->sched_task(cpuctx->task_ctx, sched_in);
3002 perf_pmu_enable(pmu);
3003 perf_ctx_unlock(cpuctx, cpuctx->task_ctx);
3007 static void perf_event_switch(struct task_struct *task,
3008 struct task_struct *next_prev, bool sched_in);
3010 #define for_each_task_context_nr(ctxn) \
3011 for ((ctxn) = 0; (ctxn) < perf_nr_task_contexts; (ctxn)++)
3014 * Called from scheduler to remove the events of the current task,
3015 * with interrupts disabled.
3017 * We stop each event and update the event value in event->count.
3019 * This does not protect us against NMI, but disable()
3020 * sets the disabled bit in the control field of event _before_
3021 * accessing the event control register. If a NMI hits, then it will
3022 * not restart the event.
3024 void __perf_event_task_sched_out(struct task_struct *task,
3025 struct task_struct *next)
3029 if (__this_cpu_read(perf_sched_cb_usages))
3030 perf_pmu_sched_task(task, next, false);
3032 if (atomic_read(&nr_switch_events))
3033 perf_event_switch(task, next, false);
3035 for_each_task_context_nr(ctxn)
3036 perf_event_context_sched_out(task, ctxn, next);
3039 * if cgroup events exist on this CPU, then we need
3040 * to check if we have to switch out PMU state.
3041 * cgroup event are system-wide mode only
3043 if (atomic_read(this_cpu_ptr(&perf_cgroup_events)))
3044 perf_cgroup_sched_out(task, next);
3048 * Called with IRQs disabled
3050 static void cpu_ctx_sched_out(struct perf_cpu_context *cpuctx,
3051 enum event_type_t event_type)
3053 ctx_sched_out(&cpuctx->ctx, cpuctx, event_type);
3057 ctx_pinned_sched_in(struct perf_event_context *ctx,
3058 struct perf_cpu_context *cpuctx)
3060 struct perf_event *event;
3062 list_for_each_entry(event, &ctx->pinned_groups, group_entry) {
3063 if (event->state <= PERF_EVENT_STATE_OFF)
3065 if (!event_filter_match(event))
3068 /* may need to reset tstamp_enabled */
3069 if (is_cgroup_event(event))
3070 perf_cgroup_mark_enabled(event, ctx);
3072 if (group_can_go_on(event, cpuctx, 1))
3073 group_sched_in(event, cpuctx, ctx);
3076 * If this pinned group hasn't been scheduled,
3077 * put it in error state.
3079 if (event->state == PERF_EVENT_STATE_INACTIVE) {
3080 update_group_times(event);
3081 event->state = PERF_EVENT_STATE_ERROR;
3087 ctx_flexible_sched_in(struct perf_event_context *ctx,
3088 struct perf_cpu_context *cpuctx)
3090 struct perf_event *event;
3093 list_for_each_entry(event, &ctx->flexible_groups, group_entry) {
3094 /* Ignore events in OFF or ERROR state */
3095 if (event->state <= PERF_EVENT_STATE_OFF)
3098 * Listen to the 'cpu' scheduling filter constraint
3101 if (!event_filter_match(event))
3104 /* may need to reset tstamp_enabled */
3105 if (is_cgroup_event(event))
3106 perf_cgroup_mark_enabled(event, ctx);
3108 if (group_can_go_on(event, cpuctx, can_add_hw)) {
3109 if (group_sched_in(event, cpuctx, ctx))
3116 ctx_sched_in(struct perf_event_context *ctx,
3117 struct perf_cpu_context *cpuctx,
3118 enum event_type_t event_type,
3119 struct task_struct *task)
3121 int is_active = ctx->is_active;
3124 lockdep_assert_held(&ctx->lock);
3126 if (likely(!ctx->nr_events))
3129 ctx->is_active |= (event_type | EVENT_TIME);
3132 cpuctx->task_ctx = ctx;
3134 WARN_ON_ONCE(cpuctx->task_ctx != ctx);
3137 is_active ^= ctx->is_active; /* changed bits */
3139 if (is_active & EVENT_TIME) {
3140 /* start ctx time */
3142 ctx->timestamp = now;
3143 perf_cgroup_set_timestamp(task, ctx);
3147 * First go through the list and put on any pinned groups
3148 * in order to give them the best chance of going on.
3150 if (is_active & EVENT_PINNED)
3151 ctx_pinned_sched_in(ctx, cpuctx);
3153 /* Then walk through the lower prio flexible groups */
3154 if (is_active & EVENT_FLEXIBLE)
3155 ctx_flexible_sched_in(ctx, cpuctx);
3158 static void cpu_ctx_sched_in(struct perf_cpu_context *cpuctx,
3159 enum event_type_t event_type,
3160 struct task_struct *task)
3162 struct perf_event_context *ctx = &cpuctx->ctx;
3164 ctx_sched_in(ctx, cpuctx, event_type, task);
3167 static void perf_event_context_sched_in(struct perf_event_context *ctx,
3168 struct task_struct *task)
3170 struct perf_cpu_context *cpuctx;
3172 cpuctx = __get_cpu_context(ctx);
3173 if (cpuctx->task_ctx == ctx)
3176 perf_ctx_lock(cpuctx, ctx);
3177 perf_pmu_disable(ctx->pmu);
3179 * We want to keep the following priority order:
3180 * cpu pinned (that don't need to move), task pinned,
3181 * cpu flexible, task flexible.
3183 * However, if task's ctx is not carrying any pinned
3184 * events, no need to flip the cpuctx's events around.
3186 if (!list_empty(&ctx->pinned_groups))
3187 cpu_ctx_sched_out(cpuctx, EVENT_FLEXIBLE);
3188 perf_event_sched_in(cpuctx, ctx, task);
3189 perf_pmu_enable(ctx->pmu);
3190 perf_ctx_unlock(cpuctx, ctx);
3194 * Called from scheduler to add the events of the current task
3195 * with interrupts disabled.
3197 * We restore the event value and then enable it.
3199 * This does not protect us against NMI, but enable()
3200 * sets the enabled bit in the control field of event _before_
3201 * accessing the event control register. If a NMI hits, then it will
3202 * keep the event running.
3204 void __perf_event_task_sched_in(struct task_struct *prev,
3205 struct task_struct *task)
3207 struct perf_event_context *ctx;
3211 * If cgroup events exist on this CPU, then we need to check if we have
3212 * to switch in PMU state; cgroup event are system-wide mode only.
3214 * Since cgroup events are CPU events, we must schedule these in before
3215 * we schedule in the task events.
3217 if (atomic_read(this_cpu_ptr(&perf_cgroup_events)))
3218 perf_cgroup_sched_in(prev, task);
3220 for_each_task_context_nr(ctxn) {
3221 ctx = task->perf_event_ctxp[ctxn];
3225 perf_event_context_sched_in(ctx, task);
3228 if (atomic_read(&nr_switch_events))
3229 perf_event_switch(task, prev, true);
3231 if (__this_cpu_read(perf_sched_cb_usages))
3232 perf_pmu_sched_task(prev, task, true);
3235 static u64 perf_calculate_period(struct perf_event *event, u64 nsec, u64 count)
3237 u64 frequency = event->attr.sample_freq;
3238 u64 sec = NSEC_PER_SEC;
3239 u64 divisor, dividend;
3241 int count_fls, nsec_fls, frequency_fls, sec_fls;
3243 count_fls = fls64(count);
3244 nsec_fls = fls64(nsec);
3245 frequency_fls = fls64(frequency);
3249 * We got @count in @nsec, with a target of sample_freq HZ
3250 * the target period becomes:
3253 * period = -------------------
3254 * @nsec * sample_freq
3259 * Reduce accuracy by one bit such that @a and @b converge
3260 * to a similar magnitude.
3262 #define REDUCE_FLS(a, b) \
3264 if (a##_fls > b##_fls) { \
3274 * Reduce accuracy until either term fits in a u64, then proceed with
3275 * the other, so that finally we can do a u64/u64 division.
3277 while (count_fls + sec_fls > 64 && nsec_fls + frequency_fls > 64) {
3278 REDUCE_FLS(nsec, frequency);
3279 REDUCE_FLS(sec, count);
3282 if (count_fls + sec_fls > 64) {
3283 divisor = nsec * frequency;
3285 while (count_fls + sec_fls > 64) {
3286 REDUCE_FLS(count, sec);
3290 dividend = count * sec;
3292 dividend = count * sec;
3294 while (nsec_fls + frequency_fls > 64) {
3295 REDUCE_FLS(nsec, frequency);
3299 divisor = nsec * frequency;
3305 return div64_u64(dividend, divisor);
3308 static DEFINE_PER_CPU(int, perf_throttled_count);
3309 static DEFINE_PER_CPU(u64, perf_throttled_seq);
3311 static void perf_adjust_period(struct perf_event *event, u64 nsec, u64 count, bool disable)
3313 struct hw_perf_event *hwc = &event->hw;
3314 s64 period, sample_period;
3317 period = perf_calculate_period(event, nsec, count);
3319 delta = (s64)(period - hwc->sample_period);
3320 delta = (delta + 7) / 8; /* low pass filter */
3322 sample_period = hwc->sample_period + delta;
3327 hwc->sample_period = sample_period;
3329 if (local64_read(&hwc->period_left) > 8*sample_period) {
3331 event->pmu->stop(event, PERF_EF_UPDATE);
3333 local64_set(&hwc->period_left, 0);
3336 event->pmu->start(event, PERF_EF_RELOAD);
3341 * combine freq adjustment with unthrottling to avoid two passes over the
3342 * events. At the same time, make sure, having freq events does not change
3343 * the rate of unthrottling as that would introduce bias.
3345 static void perf_adjust_freq_unthr_context(struct perf_event_context *ctx,
3348 struct perf_event *event;
3349 struct hw_perf_event *hwc;
3350 u64 now, period = TICK_NSEC;
3354 * only need to iterate over all events iff:
3355 * - context have events in frequency mode (needs freq adjust)
3356 * - there are events to unthrottle on this cpu
3358 if (!(ctx->nr_freq || needs_unthr))
3361 raw_spin_lock(&ctx->lock);
3362 perf_pmu_disable(ctx->pmu);
3364 list_for_each_entry_rcu(event, &ctx->event_list, event_entry) {
3365 if (event->state != PERF_EVENT_STATE_ACTIVE)
3368 if (!event_filter_match(event))
3371 perf_pmu_disable(event->pmu);
3375 if (hwc->interrupts == MAX_INTERRUPTS) {
3376 hwc->interrupts = 0;
3377 perf_log_throttle(event, 1);
3378 event->pmu->start(event, 0);
3381 if (!event->attr.freq || !event->attr.sample_freq)
3385 * stop the event and update event->count
3387 event->pmu->stop(event, PERF_EF_UPDATE);
3389 now = local64_read(&event->count);
3390 delta = now - hwc->freq_count_stamp;
3391 hwc->freq_count_stamp = now;
3395 * reload only if value has changed
3396 * we have stopped the event so tell that
3397 * to perf_adjust_period() to avoid stopping it
3401 perf_adjust_period(event, period, delta, false);
3403 event->pmu->start(event, delta > 0 ? PERF_EF_RELOAD : 0);
3405 perf_pmu_enable(event->pmu);
3408 perf_pmu_enable(ctx->pmu);
3409 raw_spin_unlock(&ctx->lock);
3413 * Round-robin a context's events:
3415 static void rotate_ctx(struct perf_event_context *ctx)
3418 * Rotate the first entry last of non-pinned groups. Rotation might be
3419 * disabled by the inheritance code.
3421 if (!ctx->rotate_disable)
3422 list_rotate_left(&ctx->flexible_groups);
3425 static int perf_rotate_context(struct perf_cpu_context *cpuctx)
3427 struct perf_event_context *ctx = NULL;
3430 if (cpuctx->ctx.nr_events) {
3431 if (cpuctx->ctx.nr_events != cpuctx->ctx.nr_active)
3435 ctx = cpuctx->task_ctx;
3436 if (ctx && ctx->nr_events) {
3437 if (ctx->nr_events != ctx->nr_active)
3444 perf_ctx_lock(cpuctx, cpuctx->task_ctx);
3445 perf_pmu_disable(cpuctx->ctx.pmu);
3447 cpu_ctx_sched_out(cpuctx, EVENT_FLEXIBLE);
3449 ctx_sched_out(ctx, cpuctx, EVENT_FLEXIBLE);
3451 rotate_ctx(&cpuctx->ctx);
3455 perf_event_sched_in(cpuctx, ctx, current);
3457 perf_pmu_enable(cpuctx->ctx.pmu);
3458 perf_ctx_unlock(cpuctx, cpuctx->task_ctx);
3464 void perf_event_task_tick(void)
3466 struct list_head *head = this_cpu_ptr(&active_ctx_list);
3467 struct perf_event_context *ctx, *tmp;
3470 WARN_ON(!irqs_disabled());
3472 __this_cpu_inc(perf_throttled_seq);
3473 throttled = __this_cpu_xchg(perf_throttled_count, 0);
3474 tick_dep_clear_cpu(smp_processor_id(), TICK_DEP_BIT_PERF_EVENTS);
3476 list_for_each_entry_safe(ctx, tmp, head, active_ctx_list)
3477 perf_adjust_freq_unthr_context(ctx, throttled);
3480 static int event_enable_on_exec(struct perf_event *event,
3481 struct perf_event_context *ctx)
3483 if (!event->attr.enable_on_exec)
3486 event->attr.enable_on_exec = 0;
3487 if (event->state >= PERF_EVENT_STATE_INACTIVE)
3490 __perf_event_mark_enabled(event);
3496 * Enable all of a task's events that have been marked enable-on-exec.
3497 * This expects task == current.
3499 static void perf_event_enable_on_exec(int ctxn)
3501 struct perf_event_context *ctx, *clone_ctx = NULL;
3502 enum event_type_t event_type = 0;
3503 struct perf_cpu_context *cpuctx;
3504 struct perf_event *event;
3505 unsigned long flags;
3508 local_irq_save(flags);
3509 ctx = current->perf_event_ctxp[ctxn];
3510 if (!ctx || !ctx->nr_events)
3513 cpuctx = __get_cpu_context(ctx);
3514 perf_ctx_lock(cpuctx, ctx);
3515 ctx_sched_out(ctx, cpuctx, EVENT_TIME);
3516 list_for_each_entry(event, &ctx->event_list, event_entry) {
3517 enabled |= event_enable_on_exec(event, ctx);
3518 event_type |= get_event_type(event);
3522 * Unclone and reschedule this context if we enabled any event.
3525 clone_ctx = unclone_ctx(ctx);
3526 ctx_resched(cpuctx, ctx, event_type);
3528 ctx_sched_in(ctx, cpuctx, EVENT_TIME, current);
3530 perf_ctx_unlock(cpuctx, ctx);
3533 local_irq_restore(flags);
3539 struct perf_read_data {
3540 struct perf_event *event;
3545 static int __perf_event_read_cpu(struct perf_event *event, int event_cpu)
3547 u16 local_pkg, event_pkg;
3549 if (event->group_caps & PERF_EV_CAP_READ_ACTIVE_PKG) {
3550 int local_cpu = smp_processor_id();
3552 event_pkg = topology_physical_package_id(event_cpu);
3553 local_pkg = topology_physical_package_id(local_cpu);
3555 if (event_pkg == local_pkg)
3563 * Cross CPU call to read the hardware event
3565 static void __perf_event_read(void *info)
3567 struct perf_read_data *data = info;
3568 struct perf_event *sub, *event = data->event;
3569 struct perf_event_context *ctx = event->ctx;
3570 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
3571 struct pmu *pmu = event->pmu;
3574 * If this is a task context, we need to check whether it is
3575 * the current task context of this cpu. If not it has been
3576 * scheduled out before the smp call arrived. In that case
3577 * event->count would have been updated to a recent sample
3578 * when the event was scheduled out.
3580 if (ctx->task && cpuctx->task_ctx != ctx)
3583 raw_spin_lock(&ctx->lock);
3584 if (ctx->is_active) {
3585 update_context_time(ctx);
3586 update_cgrp_time_from_event(event);
3589 update_event_times(event);
3590 if (event->state != PERF_EVENT_STATE_ACTIVE)
3599 pmu->start_txn(pmu, PERF_PMU_TXN_READ);
3603 list_for_each_entry(sub, &event->sibling_list, group_entry) {
3604 update_event_times(sub);
3605 if (sub->state == PERF_EVENT_STATE_ACTIVE) {
3607 * Use sibling's PMU rather than @event's since
3608 * sibling could be on different (eg: software) PMU.
3610 sub->pmu->read(sub);
3614 data->ret = pmu->commit_txn(pmu);
3617 raw_spin_unlock(&ctx->lock);
3620 static inline u64 perf_event_count(struct perf_event *event)
3622 if (event->pmu->count)
3623 return event->pmu->count(event);
3625 return __perf_event_count(event);
3629 * NMI-safe method to read a local event, that is an event that
3631 * - either for the current task, or for this CPU
3632 * - does not have inherit set, for inherited task events
3633 * will not be local and we cannot read them atomically
3634 * - must not have a pmu::count method
3636 u64 perf_event_read_local(struct perf_event *event)
3638 unsigned long flags;
3642 * Disabling interrupts avoids all counter scheduling (context
3643 * switches, timer based rotation and IPIs).
3645 local_irq_save(flags);
3647 /* If this is a per-task event, it must be for current */
3648 WARN_ON_ONCE((event->attach_state & PERF_ATTACH_TASK) &&
3649 event->hw.target != current);
3651 /* If this is a per-CPU event, it must be for this CPU */
3652 WARN_ON_ONCE(!(event->attach_state & PERF_ATTACH_TASK) &&
3653 event->cpu != smp_processor_id());
3656 * It must not be an event with inherit set, we cannot read
3657 * all child counters from atomic context.
3659 WARN_ON_ONCE(event->attr.inherit);
3662 * It must not have a pmu::count method, those are not
3665 WARN_ON_ONCE(event->pmu->count);
3668 * If the event is currently on this CPU, its either a per-task event,
3669 * or local to this CPU. Furthermore it means its ACTIVE (otherwise
3672 if (event->oncpu == smp_processor_id())
3673 event->pmu->read(event);
3675 val = local64_read(&event->count);
3676 local_irq_restore(flags);
3681 static int perf_event_read(struct perf_event *event, bool group)
3683 int event_cpu, ret = 0;
3686 * If event is enabled and currently active on a CPU, update the
3687 * value in the event structure:
3689 if (event->state == PERF_EVENT_STATE_ACTIVE) {
3690 struct perf_read_data data = {
3696 event_cpu = READ_ONCE(event->oncpu);
3697 if ((unsigned)event_cpu >= nr_cpu_ids)
3701 event_cpu = __perf_event_read_cpu(event, event_cpu);
3704 * Purposely ignore the smp_call_function_single() return
3707 * If event_cpu isn't a valid CPU it means the event got
3708 * scheduled out and that will have updated the event count.
3710 * Therefore, either way, we'll have an up-to-date event count
3713 (void)smp_call_function_single(event_cpu, __perf_event_read, &data, 1);
3716 } else if (event->state == PERF_EVENT_STATE_INACTIVE) {
3717 struct perf_event_context *ctx = event->ctx;
3718 unsigned long flags;
3720 raw_spin_lock_irqsave(&ctx->lock, flags);
3722 * may read while context is not active
3723 * (e.g., thread is blocked), in that case
3724 * we cannot update context time
3726 if (ctx->is_active) {
3727 update_context_time(ctx);
3728 update_cgrp_time_from_event(event);
3731 update_group_times(event);
3733 update_event_times(event);
3734 raw_spin_unlock_irqrestore(&ctx->lock, flags);
3741 * Initialize the perf_event context in a task_struct:
3743 static void __perf_event_init_context(struct perf_event_context *ctx)
3745 raw_spin_lock_init(&ctx->lock);
3746 mutex_init(&ctx->mutex);
3747 INIT_LIST_HEAD(&ctx->active_ctx_list);
3748 INIT_LIST_HEAD(&ctx->pinned_groups);
3749 INIT_LIST_HEAD(&ctx->flexible_groups);
3750 INIT_LIST_HEAD(&ctx->event_list);
3751 atomic_set(&ctx->refcount, 1);
3754 static struct perf_event_context *
3755 alloc_perf_context(struct pmu *pmu, struct task_struct *task)
3757 struct perf_event_context *ctx;
3759 ctx = kzalloc(sizeof(struct perf_event_context), GFP_KERNEL);
3763 __perf_event_init_context(ctx);
3766 get_task_struct(task);
3773 static struct task_struct *
3774 find_lively_task_by_vpid(pid_t vpid)
3776 struct task_struct *task;
3782 task = find_task_by_vpid(vpid);
3784 get_task_struct(task);
3788 return ERR_PTR(-ESRCH);
3794 * Returns a matching context with refcount and pincount.
3796 static struct perf_event_context *
3797 find_get_context(struct pmu *pmu, struct task_struct *task,
3798 struct perf_event *event)
3800 struct perf_event_context *ctx, *clone_ctx = NULL;
3801 struct perf_cpu_context *cpuctx;
3802 void *task_ctx_data = NULL;
3803 unsigned long flags;
3805 int cpu = event->cpu;
3808 /* Must be root to operate on a CPU event: */
3809 if (perf_paranoid_cpu() && !capable(CAP_SYS_ADMIN))
3810 return ERR_PTR(-EACCES);
3813 * We could be clever and allow to attach a event to an
3814 * offline CPU and activate it when the CPU comes up, but
3817 if (!cpu_online(cpu))
3818 return ERR_PTR(-ENODEV);
3820 cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
3829 ctxn = pmu->task_ctx_nr;
3833 if (event->attach_state & PERF_ATTACH_TASK_DATA) {
3834 task_ctx_data = kzalloc(pmu->task_ctx_size, GFP_KERNEL);
3835 if (!task_ctx_data) {
3842 ctx = perf_lock_task_context(task, ctxn, &flags);
3844 clone_ctx = unclone_ctx(ctx);
3847 if (task_ctx_data && !ctx->task_ctx_data) {
3848 ctx->task_ctx_data = task_ctx_data;
3849 task_ctx_data = NULL;
3851 raw_spin_unlock_irqrestore(&ctx->lock, flags);
3856 ctx = alloc_perf_context(pmu, task);
3861 if (task_ctx_data) {
3862 ctx->task_ctx_data = task_ctx_data;
3863 task_ctx_data = NULL;
3867 mutex_lock(&task->perf_event_mutex);
3869 * If it has already passed perf_event_exit_task().
3870 * we must see PF_EXITING, it takes this mutex too.
3872 if (task->flags & PF_EXITING)
3874 else if (task->perf_event_ctxp[ctxn])
3879 rcu_assign_pointer(task->perf_event_ctxp[ctxn], ctx);
3881 mutex_unlock(&task->perf_event_mutex);
3883 if (unlikely(err)) {
3892 kfree(task_ctx_data);
3896 kfree(task_ctx_data);
3897 return ERR_PTR(err);
3900 static void perf_event_free_filter(struct perf_event *event);
3901 static void perf_event_free_bpf_prog(struct perf_event *event);
3903 static void free_event_rcu(struct rcu_head *head)
3905 struct perf_event *event;
3907 event = container_of(head, struct perf_event, rcu_head);
3909 put_pid_ns(event->ns);
3910 perf_event_free_filter(event);
3914 static void ring_buffer_attach(struct perf_event *event,
3915 struct ring_buffer *rb);
3917 static void detach_sb_event(struct perf_event *event)
3919 struct pmu_event_list *pel = per_cpu_ptr(&pmu_sb_events, event->cpu);
3921 raw_spin_lock(&pel->lock);
3922 list_del_rcu(&event->sb_list);
3923 raw_spin_unlock(&pel->lock);
3926 static bool is_sb_event(struct perf_event *event)
3928 struct perf_event_attr *attr = &event->attr;
3933 if (event->attach_state & PERF_ATTACH_TASK)
3936 if (attr->mmap || attr->mmap_data || attr->mmap2 ||
3937 attr->comm || attr->comm_exec ||
3939 attr->context_switch)
3944 static void unaccount_pmu_sb_event(struct perf_event *event)
3946 if (is_sb_event(event))
3947 detach_sb_event(event);
3950 static void unaccount_event_cpu(struct perf_event *event, int cpu)
3955 if (is_cgroup_event(event))
3956 atomic_dec(&per_cpu(perf_cgroup_events, cpu));
3959 #ifdef CONFIG_NO_HZ_FULL
3960 static DEFINE_SPINLOCK(nr_freq_lock);
3963 static void unaccount_freq_event_nohz(void)
3965 #ifdef CONFIG_NO_HZ_FULL
3966 spin_lock(&nr_freq_lock);
3967 if (atomic_dec_and_test(&nr_freq_events))
3968 tick_nohz_dep_clear(TICK_DEP_BIT_PERF_EVENTS);
3969 spin_unlock(&nr_freq_lock);
3973 static void unaccount_freq_event(void)
3975 if (tick_nohz_full_enabled())
3976 unaccount_freq_event_nohz();
3978 atomic_dec(&nr_freq_events);
3981 static void unaccount_event(struct perf_event *event)
3988 if (event->attach_state & PERF_ATTACH_TASK)
3990 if (event->attr.mmap || event->attr.mmap_data)
3991 atomic_dec(&nr_mmap_events);
3992 if (event->attr.comm)
3993 atomic_dec(&nr_comm_events);
3994 if (event->attr.task)
3995 atomic_dec(&nr_task_events);
3996 if (event->attr.freq)
3997 unaccount_freq_event();
3998 if (event->attr.context_switch) {
4000 atomic_dec(&nr_switch_events);
4002 if (is_cgroup_event(event))
4004 if (has_branch_stack(event))
4008 if (!atomic_add_unless(&perf_sched_count, -1, 1))
4009 schedule_delayed_work(&perf_sched_work, HZ);
4012 unaccount_event_cpu(event, event->cpu);
4014 unaccount_pmu_sb_event(event);
4017 static void perf_sched_delayed(struct work_struct *work)
4019 mutex_lock(&perf_sched_mutex);
4020 if (atomic_dec_and_test(&perf_sched_count))
4021 static_branch_disable(&perf_sched_events);
4022 mutex_unlock(&perf_sched_mutex);
4026 * The following implement mutual exclusion of events on "exclusive" pmus
4027 * (PERF_PMU_CAP_EXCLUSIVE). Such pmus can only have one event scheduled
4028 * at a time, so we disallow creating events that might conflict, namely:
4030 * 1) cpu-wide events in the presence of per-task events,
4031 * 2) per-task events in the presence of cpu-wide events,
4032 * 3) two matching events on the same context.
4034 * The former two cases are handled in the allocation path (perf_event_alloc(),
4035 * _free_event()), the latter -- before the first perf_install_in_context().
4037 static int exclusive_event_init(struct perf_event *event)
4039 struct pmu *pmu = event->pmu;
4041 if (!(pmu->capabilities & PERF_PMU_CAP_EXCLUSIVE))
4045 * Prevent co-existence of per-task and cpu-wide events on the
4046 * same exclusive pmu.
4048 * Negative pmu::exclusive_cnt means there are cpu-wide
4049 * events on this "exclusive" pmu, positive means there are
4052 * Since this is called in perf_event_alloc() path, event::ctx
4053 * doesn't exist yet; it is, however, safe to use PERF_ATTACH_TASK
4054 * to mean "per-task event", because unlike other attach states it
4055 * never gets cleared.
4057 if (event->attach_state & PERF_ATTACH_TASK) {
4058 if (!atomic_inc_unless_negative(&pmu->exclusive_cnt))
4061 if (!atomic_dec_unless_positive(&pmu->exclusive_cnt))
4068 static void exclusive_event_destroy(struct perf_event *event)
4070 struct pmu *pmu = event->pmu;
4072 if (!(pmu->capabilities & PERF_PMU_CAP_EXCLUSIVE))
4075 /* see comment in exclusive_event_init() */
4076 if (event->attach_state & PERF_ATTACH_TASK)
4077 atomic_dec(&pmu->exclusive_cnt);
4079 atomic_inc(&pmu->exclusive_cnt);
4082 static bool exclusive_event_match(struct perf_event *e1, struct perf_event *e2)
4084 if ((e1->pmu == e2->pmu) &&
4085 (e1->cpu == e2->cpu ||
4092 /* Called under the same ctx::mutex as perf_install_in_context() */
4093 static bool exclusive_event_installable(struct perf_event *event,
4094 struct perf_event_context *ctx)
4096 struct perf_event *iter_event;
4097 struct pmu *pmu = event->pmu;
4099 if (!(pmu->capabilities & PERF_PMU_CAP_EXCLUSIVE))
4102 list_for_each_entry(iter_event, &ctx->event_list, event_entry) {
4103 if (exclusive_event_match(iter_event, event))
4110 static void perf_addr_filters_splice(struct perf_event *event,
4111 struct list_head *head);
4113 static void _free_event(struct perf_event *event)
4115 irq_work_sync(&event->pending);
4117 unaccount_event(event);
4121 * Can happen when we close an event with re-directed output.
4123 * Since we have a 0 refcount, perf_mmap_close() will skip
4124 * over us; possibly making our ring_buffer_put() the last.
4126 mutex_lock(&event->mmap_mutex);
4127 ring_buffer_attach(event, NULL);
4128 mutex_unlock(&event->mmap_mutex);
4131 if (is_cgroup_event(event))
4132 perf_detach_cgroup(event);
4134 if (!event->parent) {
4135 if (event->attr.sample_type & PERF_SAMPLE_CALLCHAIN)
4136 put_callchain_buffers();
4139 perf_event_free_bpf_prog(event);
4140 perf_addr_filters_splice(event, NULL);
4141 kfree(event->addr_filters_offs);
4144 event->destroy(event);
4147 put_ctx(event->ctx);
4149 exclusive_event_destroy(event);
4150 module_put(event->pmu->module);
4152 call_rcu(&event->rcu_head, free_event_rcu);
4156 * Used to free events which have a known refcount of 1, such as in error paths
4157 * where the event isn't exposed yet and inherited events.
4159 static void free_event(struct perf_event *event)
4161 if (WARN(atomic_long_cmpxchg(&event->refcount, 1, 0) != 1,
4162 "unexpected event refcount: %ld; ptr=%p\n",
4163 atomic_long_read(&event->refcount), event)) {
4164 /* leak to avoid use-after-free */
4172 * Remove user event from the owner task.
4174 static void perf_remove_from_owner(struct perf_event *event)
4176 struct task_struct *owner;
4180 * Matches the smp_store_release() in perf_event_exit_task(). If we
4181 * observe !owner it means the list deletion is complete and we can
4182 * indeed free this event, otherwise we need to serialize on
4183 * owner->perf_event_mutex.
4185 owner = lockless_dereference(event->owner);
4188 * Since delayed_put_task_struct() also drops the last
4189 * task reference we can safely take a new reference
4190 * while holding the rcu_read_lock().
4192 get_task_struct(owner);
4198 * If we're here through perf_event_exit_task() we're already
4199 * holding ctx->mutex which would be an inversion wrt. the
4200 * normal lock order.
4202 * However we can safely take this lock because its the child
4205 mutex_lock_nested(&owner->perf_event_mutex, SINGLE_DEPTH_NESTING);
4208 * We have to re-check the event->owner field, if it is cleared
4209 * we raced with perf_event_exit_task(), acquiring the mutex
4210 * ensured they're done, and we can proceed with freeing the
4214 list_del_init(&event->owner_entry);
4215 smp_store_release(&event->owner, NULL);
4217 mutex_unlock(&owner->perf_event_mutex);
4218 put_task_struct(owner);
4222 static void put_event(struct perf_event *event)
4224 if (!atomic_long_dec_and_test(&event->refcount))
4231 * Kill an event dead; while event:refcount will preserve the event
4232 * object, it will not preserve its functionality. Once the last 'user'
4233 * gives up the object, we'll destroy the thing.
4235 int perf_event_release_kernel(struct perf_event *event)
4237 struct perf_event_context *ctx = event->ctx;
4238 struct perf_event *child, *tmp;
4241 * If we got here through err_file: fput(event_file); we will not have
4242 * attached to a context yet.
4245 WARN_ON_ONCE(event->attach_state &
4246 (PERF_ATTACH_CONTEXT|PERF_ATTACH_GROUP));
4250 if (!is_kernel_event(event))
4251 perf_remove_from_owner(event);
4253 ctx = perf_event_ctx_lock(event);
4254 WARN_ON_ONCE(ctx->parent_ctx);
4255 perf_remove_from_context(event, DETACH_GROUP);
4257 raw_spin_lock_irq(&ctx->lock);
4259 * Mark this even as STATE_DEAD, there is no external reference to it
4262 * Anybody acquiring event->child_mutex after the below loop _must_
4263 * also see this, most importantly inherit_event() which will avoid
4264 * placing more children on the list.
4266 * Thus this guarantees that we will in fact observe and kill _ALL_
4269 event->state = PERF_EVENT_STATE_DEAD;
4270 raw_spin_unlock_irq(&ctx->lock);
4272 perf_event_ctx_unlock(event, ctx);
4275 mutex_lock(&event->child_mutex);
4276 list_for_each_entry(child, &event->child_list, child_list) {
4279 * Cannot change, child events are not migrated, see the
4280 * comment with perf_event_ctx_lock_nested().
4282 ctx = lockless_dereference(child->ctx);
4284 * Since child_mutex nests inside ctx::mutex, we must jump
4285 * through hoops. We start by grabbing a reference on the ctx.
4287 * Since the event cannot get freed while we hold the
4288 * child_mutex, the context must also exist and have a !0
4294 * Now that we have a ctx ref, we can drop child_mutex, and
4295 * acquire ctx::mutex without fear of it going away. Then we
4296 * can re-acquire child_mutex.
4298 mutex_unlock(&event->child_mutex);
4299 mutex_lock(&ctx->mutex);
4300 mutex_lock(&event->child_mutex);
4303 * Now that we hold ctx::mutex and child_mutex, revalidate our
4304 * state, if child is still the first entry, it didn't get freed
4305 * and we can continue doing so.
4307 tmp = list_first_entry_or_null(&event->child_list,
4308 struct perf_event, child_list);
4310 perf_remove_from_context(child, DETACH_GROUP);
4311 list_del(&child->child_list);
4314 * This matches the refcount bump in inherit_event();
4315 * this can't be the last reference.
4320 mutex_unlock(&event->child_mutex);
4321 mutex_unlock(&ctx->mutex);
4325 mutex_unlock(&event->child_mutex);
4328 put_event(event); /* Must be the 'last' reference */
4331 EXPORT_SYMBOL_GPL(perf_event_release_kernel);
4334 * Called when the last reference to the file is gone.
4336 static int perf_release(struct inode *inode, struct file *file)
4338 perf_event_release_kernel(file->private_data);
4342 u64 perf_event_read_value(struct perf_event *event, u64 *enabled, u64 *running)
4344 struct perf_event *child;
4350 mutex_lock(&event->child_mutex);
4352 (void)perf_event_read(event, false);
4353 total += perf_event_count(event);
4355 *enabled += event->total_time_enabled +
4356 atomic64_read(&event->child_total_time_enabled);
4357 *running += event->total_time_running +
4358 atomic64_read(&event->child_total_time_running);
4360 list_for_each_entry(child, &event->child_list, child_list) {
4361 (void)perf_event_read(child, false);
4362 total += perf_event_count(child);
4363 *enabled += child->total_time_enabled;
4364 *running += child->total_time_running;
4366 mutex_unlock(&event->child_mutex);
4370 EXPORT_SYMBOL_GPL(perf_event_read_value);
4372 static int __perf_read_group_add(struct perf_event *leader,
4373 u64 read_format, u64 *values)
4375 struct perf_event *sub;
4376 int n = 1; /* skip @nr */
4379 ret = perf_event_read(leader, true);
4384 * Since we co-schedule groups, {enabled,running} times of siblings
4385 * will be identical to those of the leader, so we only publish one
4388 if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED) {
4389 values[n++] += leader->total_time_enabled +
4390 atomic64_read(&leader->child_total_time_enabled);
4393 if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING) {
4394 values[n++] += leader->total_time_running +
4395 atomic64_read(&leader->child_total_time_running);
4399 * Write {count,id} tuples for every sibling.
4401 values[n++] += perf_event_count(leader);
4402 if (read_format & PERF_FORMAT_ID)
4403 values[n++] = primary_event_id(leader);
4405 list_for_each_entry(sub, &leader->sibling_list, group_entry) {
4406 values[n++] += perf_event_count(sub);
4407 if (read_format & PERF_FORMAT_ID)
4408 values[n++] = primary_event_id(sub);
4414 static int perf_read_group(struct perf_event *event,
4415 u64 read_format, char __user *buf)
4417 struct perf_event *leader = event->group_leader, *child;
4418 struct perf_event_context *ctx = leader->ctx;
4422 lockdep_assert_held(&ctx->mutex);
4424 values = kzalloc(event->read_size, GFP_KERNEL);
4428 values[0] = 1 + leader->nr_siblings;
4431 * By locking the child_mutex of the leader we effectively
4432 * lock the child list of all siblings.. XXX explain how.
4434 mutex_lock(&leader->child_mutex);
4436 ret = __perf_read_group_add(leader, read_format, values);
4440 list_for_each_entry(child, &leader->child_list, child_list) {
4441 ret = __perf_read_group_add(child, read_format, values);
4446 mutex_unlock(&leader->child_mutex);
4448 ret = event->read_size;
4449 if (copy_to_user(buf, values, event->read_size))
4454 mutex_unlock(&leader->child_mutex);
4460 static int perf_read_one(struct perf_event *event,
4461 u64 read_format, char __user *buf)
4463 u64 enabled, running;
4467 values[n++] = perf_event_read_value(event, &enabled, &running);
4468 if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED)
4469 values[n++] = enabled;
4470 if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING)
4471 values[n++] = running;
4472 if (read_format & PERF_FORMAT_ID)
4473 values[n++] = primary_event_id(event);
4475 if (copy_to_user(buf, values, n * sizeof(u64)))
4478 return n * sizeof(u64);
4481 static bool is_event_hup(struct perf_event *event)
4485 if (event->state > PERF_EVENT_STATE_EXIT)
4488 mutex_lock(&event->child_mutex);
4489 no_children = list_empty(&event->child_list);
4490 mutex_unlock(&event->child_mutex);
4495 * Read the performance event - simple non blocking version for now
4498 __perf_read(struct perf_event *event, char __user *buf, size_t count)
4500 u64 read_format = event->attr.read_format;
4504 * Return end-of-file for a read on a event that is in
4505 * error state (i.e. because it was pinned but it couldn't be
4506 * scheduled on to the CPU at some point).
4508 if (event->state == PERF_EVENT_STATE_ERROR)
4511 if (count < event->read_size)
4514 WARN_ON_ONCE(event->ctx->parent_ctx);
4515 if (read_format & PERF_FORMAT_GROUP)
4516 ret = perf_read_group(event, read_format, buf);
4518 ret = perf_read_one(event, read_format, buf);
4524 perf_read(struct file *file, char __user *buf, size_t count, loff_t *ppos)
4526 struct perf_event *event = file->private_data;
4527 struct perf_event_context *ctx;
4530 ctx = perf_event_ctx_lock(event);
4531 ret = __perf_read(event, buf, count);
4532 perf_event_ctx_unlock(event, ctx);
4537 static unsigned int perf_poll(struct file *file, poll_table *wait)
4539 struct perf_event *event = file->private_data;
4540 struct ring_buffer *rb;
4541 unsigned int events = POLLHUP;
4543 poll_wait(file, &event->waitq, wait);
4545 if (is_event_hup(event))
4549 * Pin the event->rb by taking event->mmap_mutex; otherwise
4550 * perf_event_set_output() can swizzle our rb and make us miss wakeups.
4552 mutex_lock(&event->mmap_mutex);
4555 events = atomic_xchg(&rb->poll, 0);
4556 mutex_unlock(&event->mmap_mutex);
4560 static void _perf_event_reset(struct perf_event *event)
4562 (void)perf_event_read(event, false);
4563 local64_set(&event->count, 0);
4564 perf_event_update_userpage(event);
4568 * Holding the top-level event's child_mutex means that any
4569 * descendant process that has inherited this event will block
4570 * in perf_event_exit_event() if it goes to exit, thus satisfying the
4571 * task existence requirements of perf_event_enable/disable.
4573 static void perf_event_for_each_child(struct perf_event *event,
4574 void (*func)(struct perf_event *))
4576 struct perf_event *child;
4578 WARN_ON_ONCE(event->ctx->parent_ctx);
4580 mutex_lock(&event->child_mutex);
4582 list_for_each_entry(child, &event->child_list, child_list)
4584 mutex_unlock(&event->child_mutex);
4587 static void perf_event_for_each(struct perf_event *event,
4588 void (*func)(struct perf_event *))
4590 struct perf_event_context *ctx = event->ctx;
4591 struct perf_event *sibling;
4593 lockdep_assert_held(&ctx->mutex);
4595 event = event->group_leader;
4597 perf_event_for_each_child(event, func);
4598 list_for_each_entry(sibling, &event->sibling_list, group_entry)
4599 perf_event_for_each_child(sibling, func);
4602 static void __perf_event_period(struct perf_event *event,
4603 struct perf_cpu_context *cpuctx,
4604 struct perf_event_context *ctx,
4607 u64 value = *((u64 *)info);
4610 if (event->attr.freq) {
4611 event->attr.sample_freq = value;
4613 event->attr.sample_period = value;
4614 event->hw.sample_period = value;
4617 active = (event->state == PERF_EVENT_STATE_ACTIVE);
4619 perf_pmu_disable(ctx->pmu);
4621 * We could be throttled; unthrottle now to avoid the tick
4622 * trying to unthrottle while we already re-started the event.
4624 if (event->hw.interrupts == MAX_INTERRUPTS) {
4625 event->hw.interrupts = 0;
4626 perf_log_throttle(event, 1);
4628 event->pmu->stop(event, PERF_EF_UPDATE);
4631 local64_set(&event->hw.period_left, 0);
4634 event->pmu->start(event, PERF_EF_RELOAD);
4635 perf_pmu_enable(ctx->pmu);
4639 static int perf_event_period(struct perf_event *event, u64 __user *arg)
4643 if (!is_sampling_event(event))
4646 if (copy_from_user(&value, arg, sizeof(value)))
4652 if (event->attr.freq && value > sysctl_perf_event_sample_rate)
4655 event_function_call(event, __perf_event_period, &value);
4660 static const struct file_operations perf_fops;
4662 static inline int perf_fget_light(int fd, struct fd *p)
4664 struct fd f = fdget(fd);
4668 if (f.file->f_op != &perf_fops) {
4676 static int perf_event_set_output(struct perf_event *event,
4677 struct perf_event *output_event);
4678 static int perf_event_set_filter(struct perf_event *event, void __user *arg);
4679 static int perf_event_set_bpf_prog(struct perf_event *event, u32 prog_fd);
4681 static long _perf_ioctl(struct perf_event *event, unsigned int cmd, unsigned long arg)
4683 void (*func)(struct perf_event *);
4687 case PERF_EVENT_IOC_ENABLE:
4688 func = _perf_event_enable;
4690 case PERF_EVENT_IOC_DISABLE:
4691 func = _perf_event_disable;
4693 case PERF_EVENT_IOC_RESET:
4694 func = _perf_event_reset;
4697 case PERF_EVENT_IOC_REFRESH:
4698 return _perf_event_refresh(event, arg);
4700 case PERF_EVENT_IOC_PERIOD:
4701 return perf_event_period(event, (u64 __user *)arg);
4703 case PERF_EVENT_IOC_ID:
4705 u64 id = primary_event_id(event);
4707 if (copy_to_user((void __user *)arg, &id, sizeof(id)))
4712 case PERF_EVENT_IOC_SET_OUTPUT:
4716 struct perf_event *output_event;
4718 ret = perf_fget_light(arg, &output);
4721 output_event = output.file->private_data;
4722 ret = perf_event_set_output(event, output_event);
4725 ret = perf_event_set_output(event, NULL);
4730 case PERF_EVENT_IOC_SET_FILTER:
4731 return perf_event_set_filter(event, (void __user *)arg);
4733 case PERF_EVENT_IOC_SET_BPF:
4734 return perf_event_set_bpf_prog(event, arg);
4736 case PERF_EVENT_IOC_PAUSE_OUTPUT: {
4737 struct ring_buffer *rb;
4740 rb = rcu_dereference(event->rb);
4741 if (!rb || !rb->nr_pages) {
4745 rb_toggle_paused(rb, !!arg);
4753 if (flags & PERF_IOC_FLAG_GROUP)
4754 perf_event_for_each(event, func);
4756 perf_event_for_each_child(event, func);
4761 static long perf_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
4763 struct perf_event *event = file->private_data;
4764 struct perf_event_context *ctx;
4767 ctx = perf_event_ctx_lock(event);
4768 ret = _perf_ioctl(event, cmd, arg);
4769 perf_event_ctx_unlock(event, ctx);
4774 #ifdef CONFIG_COMPAT
4775 static long perf_compat_ioctl(struct file *file, unsigned int cmd,
4778 switch (_IOC_NR(cmd)) {
4779 case _IOC_NR(PERF_EVENT_IOC_SET_FILTER):
4780 case _IOC_NR(PERF_EVENT_IOC_ID):
4781 /* Fix up pointer size (usually 4 -> 8 in 32-on-64-bit case */
4782 if (_IOC_SIZE(cmd) == sizeof(compat_uptr_t)) {
4783 cmd &= ~IOCSIZE_MASK;
4784 cmd |= sizeof(void *) << IOCSIZE_SHIFT;
4788 return perf_ioctl(file, cmd, arg);
4791 # define perf_compat_ioctl NULL
4794 int perf_event_task_enable(void)
4796 struct perf_event_context *ctx;
4797 struct perf_event *event;
4799 mutex_lock(¤t->perf_event_mutex);
4800 list_for_each_entry(event, ¤t->perf_event_list, owner_entry) {
4801 ctx = perf_event_ctx_lock(event);
4802 perf_event_for_each_child(event, _perf_event_enable);
4803 perf_event_ctx_unlock(event, ctx);
4805 mutex_unlock(¤t->perf_event_mutex);
4810 int perf_event_task_disable(void)
4812 struct perf_event_context *ctx;
4813 struct perf_event *event;
4815 mutex_lock(¤t->perf_event_mutex);
4816 list_for_each_entry(event, ¤t->perf_event_list, owner_entry) {
4817 ctx = perf_event_ctx_lock(event);
4818 perf_event_for_each_child(event, _perf_event_disable);
4819 perf_event_ctx_unlock(event, ctx);
4821 mutex_unlock(¤t->perf_event_mutex);
4826 static int perf_event_index(struct perf_event *event)
4828 if (event->hw.state & PERF_HES_STOPPED)
4831 if (event->state != PERF_EVENT_STATE_ACTIVE)
4834 return event->pmu->event_idx(event);
4837 static void calc_timer_values(struct perf_event *event,
4844 *now = perf_clock();
4845 ctx_time = event->shadow_ctx_time + *now;
4846 *enabled = ctx_time - event->tstamp_enabled;
4847 *running = ctx_time - event->tstamp_running;
4850 static void perf_event_init_userpage(struct perf_event *event)
4852 struct perf_event_mmap_page *userpg;
4853 struct ring_buffer *rb;
4856 rb = rcu_dereference(event->rb);
4860 userpg = rb->user_page;
4862 /* Allow new userspace to detect that bit 0 is deprecated */
4863 userpg->cap_bit0_is_deprecated = 1;
4864 userpg->size = offsetof(struct perf_event_mmap_page, __reserved);
4865 userpg->data_offset = PAGE_SIZE;
4866 userpg->data_size = perf_data_size(rb);
4872 void __weak arch_perf_update_userpage(
4873 struct perf_event *event, struct perf_event_mmap_page *userpg, u64 now)
4878 * Callers need to ensure there can be no nesting of this function, otherwise
4879 * the seqlock logic goes bad. We can not serialize this because the arch
4880 * code calls this from NMI context.
4882 void perf_event_update_userpage(struct perf_event *event)
4884 struct perf_event_mmap_page *userpg;
4885 struct ring_buffer *rb;
4886 u64 enabled, running, now;
4889 rb = rcu_dereference(event->rb);
4894 * compute total_time_enabled, total_time_running
4895 * based on snapshot values taken when the event
4896 * was last scheduled in.
4898 * we cannot simply called update_context_time()
4899 * because of locking issue as we can be called in
4902 calc_timer_values(event, &now, &enabled, &running);
4904 userpg = rb->user_page;
4906 * Disable preemption so as to not let the corresponding user-space
4907 * spin too long if we get preempted.
4912 userpg->index = perf_event_index(event);
4913 userpg->offset = perf_event_count(event);
4915 userpg->offset -= local64_read(&event->hw.prev_count);
4917 userpg->time_enabled = enabled +
4918 atomic64_read(&event->child_total_time_enabled);
4920 userpg->time_running = running +
4921 atomic64_read(&event->child_total_time_running);
4923 arch_perf_update_userpage(event, userpg, now);
4932 static int perf_mmap_fault(struct vm_fault *vmf)
4934 struct perf_event *event = vmf->vma->vm_file->private_data;
4935 struct ring_buffer *rb;
4936 int ret = VM_FAULT_SIGBUS;
4938 if (vmf->flags & FAULT_FLAG_MKWRITE) {
4939 if (vmf->pgoff == 0)
4945 rb = rcu_dereference(event->rb);
4949 if (vmf->pgoff && (vmf->flags & FAULT_FLAG_WRITE))
4952 vmf->page = perf_mmap_to_page(rb, vmf->pgoff);
4956 get_page(vmf->page);
4957 vmf->page->mapping = vmf->vma->vm_file->f_mapping;
4958 vmf->page->index = vmf->pgoff;
4967 static void ring_buffer_attach(struct perf_event *event,
4968 struct ring_buffer *rb)
4970 struct ring_buffer *old_rb = NULL;
4971 unsigned long flags;
4975 * Should be impossible, we set this when removing
4976 * event->rb_entry and wait/clear when adding event->rb_entry.
4978 WARN_ON_ONCE(event->rcu_pending);
4981 spin_lock_irqsave(&old_rb->event_lock, flags);
4982 list_del_rcu(&event->rb_entry);
4983 spin_unlock_irqrestore(&old_rb->event_lock, flags);
4985 event->rcu_batches = get_state_synchronize_rcu();
4986 event->rcu_pending = 1;
4990 if (event->rcu_pending) {
4991 cond_synchronize_rcu(event->rcu_batches);
4992 event->rcu_pending = 0;
4995 spin_lock_irqsave(&rb->event_lock, flags);
4996 list_add_rcu(&event->rb_entry, &rb->event_list);
4997 spin_unlock_irqrestore(&rb->event_lock, flags);
5001 * Avoid racing with perf_mmap_close(AUX): stop the event
5002 * before swizzling the event::rb pointer; if it's getting
5003 * unmapped, its aux_mmap_count will be 0 and it won't
5004 * restart. See the comment in __perf_pmu_output_stop().
5006 * Data will inevitably be lost when set_output is done in
5007 * mid-air, but then again, whoever does it like this is
5008 * not in for the data anyway.
5011 perf_event_stop(event, 0);
5013 rcu_assign_pointer(event->rb, rb);
5016 ring_buffer_put(old_rb);
5018 * Since we detached before setting the new rb, so that we
5019 * could attach the new rb, we could have missed a wakeup.
5022 wake_up_all(&event->waitq);
5026 static void ring_buffer_wakeup(struct perf_event *event)
5028 struct ring_buffer *rb;
5031 rb = rcu_dereference(event->rb);
5033 list_for_each_entry_rcu(event, &rb->event_list, rb_entry)
5034 wake_up_all(&event->waitq);
5039 struct ring_buffer *ring_buffer_get(struct perf_event *event)
5041 struct ring_buffer *rb;
5044 rb = rcu_dereference(event->rb);
5046 if (!atomic_inc_not_zero(&rb->refcount))
5054 void ring_buffer_put(struct ring_buffer *rb)
5056 if (!atomic_dec_and_test(&rb->refcount))
5059 WARN_ON_ONCE(!list_empty(&rb->event_list));
5061 call_rcu(&rb->rcu_head, rb_free_rcu);
5064 static void perf_mmap_open(struct vm_area_struct *vma)
5066 struct perf_event *event = vma->vm_file->private_data;
5068 atomic_inc(&event->mmap_count);
5069 atomic_inc(&event->rb->mmap_count);
5072 atomic_inc(&event->rb->aux_mmap_count);
5074 if (event->pmu->event_mapped)
5075 event->pmu->event_mapped(event);
5078 static void perf_pmu_output_stop(struct perf_event *event);
5081 * A buffer can be mmap()ed multiple times; either directly through the same
5082 * event, or through other events by use of perf_event_set_output().
5084 * In order to undo the VM accounting done by perf_mmap() we need to destroy
5085 * the buffer here, where we still have a VM context. This means we need
5086 * to detach all events redirecting to us.
5088 static void perf_mmap_close(struct vm_area_struct *vma)
5090 struct perf_event *event = vma->vm_file->private_data;
5092 struct ring_buffer *rb = ring_buffer_get(event);
5093 struct user_struct *mmap_user = rb->mmap_user;
5094 int mmap_locked = rb->mmap_locked;
5095 unsigned long size = perf_data_size(rb);
5097 if (event->pmu->event_unmapped)
5098 event->pmu->event_unmapped(event);
5101 * rb->aux_mmap_count will always drop before rb->mmap_count and
5102 * event->mmap_count, so it is ok to use event->mmap_mutex to
5103 * serialize with perf_mmap here.
5105 if (rb_has_aux(rb) && vma->vm_pgoff == rb->aux_pgoff &&
5106 atomic_dec_and_mutex_lock(&rb->aux_mmap_count, &event->mmap_mutex)) {
5108 * Stop all AUX events that are writing to this buffer,
5109 * so that we can free its AUX pages and corresponding PMU
5110 * data. Note that after rb::aux_mmap_count dropped to zero,
5111 * they won't start any more (see perf_aux_output_begin()).
5113 perf_pmu_output_stop(event);
5115 /* now it's safe to free the pages */
5116 atomic_long_sub(rb->aux_nr_pages, &mmap_user->locked_vm);
5117 vma->vm_mm->pinned_vm -= rb->aux_mmap_locked;
5119 /* this has to be the last one */
5121 WARN_ON_ONCE(atomic_read(&rb->aux_refcount));
5123 mutex_unlock(&event->mmap_mutex);
5126 atomic_dec(&rb->mmap_count);
5128 if (!atomic_dec_and_mutex_lock(&event->mmap_count, &event->mmap_mutex))
5131 ring_buffer_attach(event, NULL);
5132 mutex_unlock(&event->mmap_mutex);
5134 /* If there's still other mmap()s of this buffer, we're done. */
5135 if (atomic_read(&rb->mmap_count))
5139 * No other mmap()s, detach from all other events that might redirect
5140 * into the now unreachable buffer. Somewhat complicated by the
5141 * fact that rb::event_lock otherwise nests inside mmap_mutex.
5145 list_for_each_entry_rcu(event, &rb->event_list, rb_entry) {
5146 if (!atomic_long_inc_not_zero(&event->refcount)) {
5148 * This event is en-route to free_event() which will
5149 * detach it and remove it from the list.
5155 mutex_lock(&event->mmap_mutex);
5157 * Check we didn't race with perf_event_set_output() which can
5158 * swizzle the rb from under us while we were waiting to
5159 * acquire mmap_mutex.
5161 * If we find a different rb; ignore this event, a next
5162 * iteration will no longer find it on the list. We have to
5163 * still restart the iteration to make sure we're not now
5164 * iterating the wrong list.
5166 if (event->rb == rb)
5167 ring_buffer_attach(event, NULL);
5169 mutex_unlock(&event->mmap_mutex);
5173 * Restart the iteration; either we're on the wrong list or
5174 * destroyed its integrity by doing a deletion.
5181 * It could be there's still a few 0-ref events on the list; they'll
5182 * get cleaned up by free_event() -- they'll also still have their
5183 * ref on the rb and will free it whenever they are done with it.
5185 * Aside from that, this buffer is 'fully' detached and unmapped,
5186 * undo the VM accounting.
5189 atomic_long_sub((size >> PAGE_SHIFT) + 1, &mmap_user->locked_vm);
5190 vma->vm_mm->pinned_vm -= mmap_locked;
5191 free_uid(mmap_user);
5194 ring_buffer_put(rb); /* could be last */
5197 static const struct vm_operations_struct perf_mmap_vmops = {
5198 .open = perf_mmap_open,
5199 .close = perf_mmap_close, /* non mergable */
5200 .fault = perf_mmap_fault,
5201 .page_mkwrite = perf_mmap_fault,
5204 static int perf_mmap(struct file *file, struct vm_area_struct *vma)
5206 struct perf_event *event = file->private_data;
5207 unsigned long user_locked, user_lock_limit;
5208 struct user_struct *user = current_user();
5209 unsigned long locked, lock_limit;
5210 struct ring_buffer *rb = NULL;
5211 unsigned long vma_size;
5212 unsigned long nr_pages;
5213 long user_extra = 0, extra = 0;
5214 int ret = 0, flags = 0;
5217 * Don't allow mmap() of inherited per-task counters. This would
5218 * create a performance issue due to all children writing to the
5221 if (event->cpu == -1 && event->attr.inherit)
5224 if (!(vma->vm_flags & VM_SHARED))
5227 vma_size = vma->vm_end - vma->vm_start;
5229 if (vma->vm_pgoff == 0) {
5230 nr_pages = (vma_size / PAGE_SIZE) - 1;
5233 * AUX area mapping: if rb->aux_nr_pages != 0, it's already
5234 * mapped, all subsequent mappings should have the same size
5235 * and offset. Must be above the normal perf buffer.
5237 u64 aux_offset, aux_size;
5242 nr_pages = vma_size / PAGE_SIZE;
5244 mutex_lock(&event->mmap_mutex);
5251 aux_offset = ACCESS_ONCE(rb->user_page->aux_offset);
5252 aux_size = ACCESS_ONCE(rb->user_page->aux_size);
5254 if (aux_offset < perf_data_size(rb) + PAGE_SIZE)
5257 if (aux_offset != vma->vm_pgoff << PAGE_SHIFT)
5260 /* already mapped with a different offset */
5261 if (rb_has_aux(rb) && rb->aux_pgoff != vma->vm_pgoff)
5264 if (aux_size != vma_size || aux_size != nr_pages * PAGE_SIZE)
5267 /* already mapped with a different size */
5268 if (rb_has_aux(rb) && rb->aux_nr_pages != nr_pages)
5271 if (!is_power_of_2(nr_pages))
5274 if (!atomic_inc_not_zero(&rb->mmap_count))
5277 if (rb_has_aux(rb)) {
5278 atomic_inc(&rb->aux_mmap_count);
5283 atomic_set(&rb->aux_mmap_count, 1);
5284 user_extra = nr_pages;
5290 * If we have rb pages ensure they're a power-of-two number, so we
5291 * can do bitmasks instead of modulo.
5293 if (nr_pages != 0 && !is_power_of_2(nr_pages))
5296 if (vma_size != PAGE_SIZE * (1 + nr_pages))
5299 WARN_ON_ONCE(event->ctx->parent_ctx);
5301 mutex_lock(&event->mmap_mutex);
5303 if (event->rb->nr_pages != nr_pages) {
5308 if (!atomic_inc_not_zero(&event->rb->mmap_count)) {
5310 * Raced against perf_mmap_close() through
5311 * perf_event_set_output(). Try again, hope for better
5314 mutex_unlock(&event->mmap_mutex);
5321 user_extra = nr_pages + 1;
5324 user_lock_limit = sysctl_perf_event_mlock >> (PAGE_SHIFT - 10);
5327 * Increase the limit linearly with more CPUs:
5329 user_lock_limit *= num_online_cpus();
5331 user_locked = atomic_long_read(&user->locked_vm) + user_extra;
5333 if (user_locked > user_lock_limit)
5334 extra = user_locked - user_lock_limit;
5336 lock_limit = rlimit(RLIMIT_MEMLOCK);
5337 lock_limit >>= PAGE_SHIFT;
5338 locked = vma->vm_mm->pinned_vm + extra;
5340 if ((locked > lock_limit) && perf_paranoid_tracepoint_raw() &&
5341 !capable(CAP_IPC_LOCK)) {
5346 WARN_ON(!rb && event->rb);
5348 if (vma->vm_flags & VM_WRITE)
5349 flags |= RING_BUFFER_WRITABLE;
5352 rb = rb_alloc(nr_pages,
5353 event->attr.watermark ? event->attr.wakeup_watermark : 0,
5361 atomic_set(&rb->mmap_count, 1);
5362 rb->mmap_user = get_current_user();
5363 rb->mmap_locked = extra;
5365 ring_buffer_attach(event, rb);
5367 perf_event_init_userpage(event);
5368 perf_event_update_userpage(event);
5370 ret = rb_alloc_aux(rb, event, vma->vm_pgoff, nr_pages,
5371 event->attr.aux_watermark, flags);
5373 rb->aux_mmap_locked = extra;
5378 atomic_long_add(user_extra, &user->locked_vm);
5379 vma->vm_mm->pinned_vm += extra;
5381 atomic_inc(&event->mmap_count);
5383 atomic_dec(&rb->mmap_count);
5386 mutex_unlock(&event->mmap_mutex);
5389 * Since pinned accounting is per vm we cannot allow fork() to copy our
5392 vma->vm_flags |= VM_DONTCOPY | VM_DONTEXPAND | VM_DONTDUMP;
5393 vma->vm_ops = &perf_mmap_vmops;
5395 if (event->pmu->event_mapped)
5396 event->pmu->event_mapped(event);
5401 static int perf_fasync(int fd, struct file *filp, int on)
5403 struct inode *inode = file_inode(filp);
5404 struct perf_event *event = filp->private_data;
5408 retval = fasync_helper(fd, filp, on, &event->fasync);
5409 inode_unlock(inode);
5417 static const struct file_operations perf_fops = {
5418 .llseek = no_llseek,
5419 .release = perf_release,
5422 .unlocked_ioctl = perf_ioctl,
5423 .compat_ioctl = perf_compat_ioctl,
5425 .fasync = perf_fasync,
5431 * If there's data, ensure we set the poll() state and publish everything
5432 * to user-space before waking everybody up.
5435 static inline struct fasync_struct **perf_event_fasync(struct perf_event *event)
5437 /* only the parent has fasync state */
5439 event = event->parent;
5440 return &event->fasync;
5443 void perf_event_wakeup(struct perf_event *event)
5445 ring_buffer_wakeup(event);
5447 if (event->pending_kill) {
5448 kill_fasync(perf_event_fasync(event), SIGIO, event->pending_kill);
5449 event->pending_kill = 0;
5453 static void perf_pending_event(struct irq_work *entry)
5455 struct perf_event *event = container_of(entry,
5456 struct perf_event, pending);
5459 rctx = perf_swevent_get_recursion_context();
5461 * If we 'fail' here, that's OK, it means recursion is already disabled
5462 * and we won't recurse 'further'.
5465 if (event->pending_disable) {
5466 event->pending_disable = 0;
5467 perf_event_disable_local(event);
5470 if (event->pending_wakeup) {
5471 event->pending_wakeup = 0;
5472 perf_event_wakeup(event);
5476 perf_swevent_put_recursion_context(rctx);
5480 * We assume there is only KVM supporting the callbacks.
5481 * Later on, we might change it to a list if there is
5482 * another virtualization implementation supporting the callbacks.
5484 struct perf_guest_info_callbacks *perf_guest_cbs;
5486 int perf_register_guest_info_callbacks(struct perf_guest_info_callbacks *cbs)
5488 perf_guest_cbs = cbs;
5491 EXPORT_SYMBOL_GPL(perf_register_guest_info_callbacks);
5493 int perf_unregister_guest_info_callbacks(struct perf_guest_info_callbacks *cbs)
5495 perf_guest_cbs = NULL;
5498 EXPORT_SYMBOL_GPL(perf_unregister_guest_info_callbacks);
5501 perf_output_sample_regs(struct perf_output_handle *handle,
5502 struct pt_regs *regs, u64 mask)
5505 DECLARE_BITMAP(_mask, 64);
5507 bitmap_from_u64(_mask, mask);
5508 for_each_set_bit(bit, _mask, sizeof(mask) * BITS_PER_BYTE) {
5511 val = perf_reg_value(regs, bit);
5512 perf_output_put(handle, val);
5516 static void perf_sample_regs_user(struct perf_regs *regs_user,
5517 struct pt_regs *regs,
5518 struct pt_regs *regs_user_copy)
5520 if (user_mode(regs)) {
5521 regs_user->abi = perf_reg_abi(current);
5522 regs_user->regs = regs;
5523 } else if (current->mm) {
5524 perf_get_regs_user(regs_user, regs, regs_user_copy);
5526 regs_user->abi = PERF_SAMPLE_REGS_ABI_NONE;
5527 regs_user->regs = NULL;
5531 static void perf_sample_regs_intr(struct perf_regs *regs_intr,
5532 struct pt_regs *regs)
5534 regs_intr->regs = regs;
5535 regs_intr->abi = perf_reg_abi(current);
5540 * Get remaining task size from user stack pointer.
5542 * It'd be better to take stack vma map and limit this more
5543 * precisly, but there's no way to get it safely under interrupt,
5544 * so using TASK_SIZE as limit.
5546 static u64 perf_ustack_task_size(struct pt_regs *regs)
5548 unsigned long addr = perf_user_stack_pointer(regs);
5550 if (!addr || addr >= TASK_SIZE)
5553 return TASK_SIZE - addr;
5557 perf_sample_ustack_size(u16 stack_size, u16 header_size,
5558 struct pt_regs *regs)
5562 /* No regs, no stack pointer, no dump. */
5567 * Check if we fit in with the requested stack size into the:
5569 * If we don't, we limit the size to the TASK_SIZE.
5571 * - remaining sample size
5572 * If we don't, we customize the stack size to
5573 * fit in to the remaining sample size.
5576 task_size = min((u64) USHRT_MAX, perf_ustack_task_size(regs));
5577 stack_size = min(stack_size, (u16) task_size);
5579 /* Current header size plus static size and dynamic size. */
5580 header_size += 2 * sizeof(u64);
5582 /* Do we fit in with the current stack dump size? */
5583 if ((u16) (header_size + stack_size) < header_size) {
5585 * If we overflow the maximum size for the sample,
5586 * we customize the stack dump size to fit in.
5588 stack_size = USHRT_MAX - header_size - sizeof(u64);
5589 stack_size = round_up(stack_size, sizeof(u64));
5596 perf_output_sample_ustack(struct perf_output_handle *handle, u64 dump_size,
5597 struct pt_regs *regs)
5599 /* Case of a kernel thread, nothing to dump */
5602 perf_output_put(handle, size);
5611 * - the size requested by user or the best one we can fit
5612 * in to the sample max size
5614 * - user stack dump data
5616 * - the actual dumped size
5620 perf_output_put(handle, dump_size);
5623 sp = perf_user_stack_pointer(regs);
5624 rem = __output_copy_user(handle, (void *) sp, dump_size);
5625 dyn_size = dump_size - rem;
5627 perf_output_skip(handle, rem);
5630 perf_output_put(handle, dyn_size);
5634 static void __perf_event_header__init_id(struct perf_event_header *header,
5635 struct perf_sample_data *data,
5636 struct perf_event *event)
5638 u64 sample_type = event->attr.sample_type;
5640 data->type = sample_type;
5641 header->size += event->id_header_size;
5643 if (sample_type & PERF_SAMPLE_TID) {
5644 /* namespace issues */
5645 data->tid_entry.pid = perf_event_pid(event, current);
5646 data->tid_entry.tid = perf_event_tid(event, current);
5649 if (sample_type & PERF_SAMPLE_TIME)
5650 data->time = perf_event_clock(event);
5652 if (sample_type & (PERF_SAMPLE_ID | PERF_SAMPLE_IDENTIFIER))
5653 data->id = primary_event_id(event);
5655 if (sample_type & PERF_SAMPLE_STREAM_ID)
5656 data->stream_id = event->id;
5658 if (sample_type & PERF_SAMPLE_CPU) {
5659 data->cpu_entry.cpu = raw_smp_processor_id();
5660 data->cpu_entry.reserved = 0;
5664 void perf_event_header__init_id(struct perf_event_header *header,
5665 struct perf_sample_data *data,
5666 struct perf_event *event)
5668 if (event->attr.sample_id_all)
5669 __perf_event_header__init_id(header, data, event);
5672 static void __perf_event__output_id_sample(struct perf_output_handle *handle,
5673 struct perf_sample_data *data)
5675 u64 sample_type = data->type;
5677 if (sample_type & PERF_SAMPLE_TID)
5678 perf_output_put(handle, data->tid_entry);
5680 if (sample_type & PERF_SAMPLE_TIME)
5681 perf_output_put(handle, data->time);
5683 if (sample_type & PERF_SAMPLE_ID)
5684 perf_output_put(handle, data->id);
5686 if (sample_type & PERF_SAMPLE_STREAM_ID)
5687 perf_output_put(handle, data->stream_id);
5689 if (sample_type & PERF_SAMPLE_CPU)
5690 perf_output_put(handle, data->cpu_entry);
5692 if (sample_type & PERF_SAMPLE_IDENTIFIER)
5693 perf_output_put(handle, data->id);
5696 void perf_event__output_id_sample(struct perf_event *event,
5697 struct perf_output_handle *handle,
5698 struct perf_sample_data *sample)
5700 if (event->attr.sample_id_all)
5701 __perf_event__output_id_sample(handle, sample);
5704 static void perf_output_read_one(struct perf_output_handle *handle,
5705 struct perf_event *event,
5706 u64 enabled, u64 running)
5708 u64 read_format = event->attr.read_format;
5712 values[n++] = perf_event_count(event);
5713 if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED) {
5714 values[n++] = enabled +
5715 atomic64_read(&event->child_total_time_enabled);
5717 if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING) {
5718 values[n++] = running +
5719 atomic64_read(&event->child_total_time_running);
5721 if (read_format & PERF_FORMAT_ID)
5722 values[n++] = primary_event_id(event);
5724 __output_copy(handle, values, n * sizeof(u64));
5728 * XXX PERF_FORMAT_GROUP vs inherited events seems difficult.
5730 static void perf_output_read_group(struct perf_output_handle *handle,
5731 struct perf_event *event,
5732 u64 enabled, u64 running)
5734 struct perf_event *leader = event->group_leader, *sub;
5735 u64 read_format = event->attr.read_format;
5739 values[n++] = 1 + leader->nr_siblings;
5741 if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED)
5742 values[n++] = enabled;
5744 if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING)
5745 values[n++] = running;
5747 if (leader != event)
5748 leader->pmu->read(leader);
5750 values[n++] = perf_event_count(leader);
5751 if (read_format & PERF_FORMAT_ID)
5752 values[n++] = primary_event_id(leader);
5754 __output_copy(handle, values, n * sizeof(u64));
5756 list_for_each_entry(sub, &leader->sibling_list, group_entry) {
5759 if ((sub != event) &&
5760 (sub->state == PERF_EVENT_STATE_ACTIVE))
5761 sub->pmu->read(sub);
5763 values[n++] = perf_event_count(sub);
5764 if (read_format & PERF_FORMAT_ID)
5765 values[n++] = primary_event_id(sub);
5767 __output_copy(handle, values, n * sizeof(u64));
5771 #define PERF_FORMAT_TOTAL_TIMES (PERF_FORMAT_TOTAL_TIME_ENABLED|\
5772 PERF_FORMAT_TOTAL_TIME_RUNNING)
5774 static void perf_output_read(struct perf_output_handle *handle,
5775 struct perf_event *event)
5777 u64 enabled = 0, running = 0, now;
5778 u64 read_format = event->attr.read_format;
5781 * compute total_time_enabled, total_time_running
5782 * based on snapshot values taken when the event
5783 * was last scheduled in.
5785 * we cannot simply called update_context_time()
5786 * because of locking issue as we are called in
5789 if (read_format & PERF_FORMAT_TOTAL_TIMES)
5790 calc_timer_values(event, &now, &enabled, &running);
5792 if (event->attr.read_format & PERF_FORMAT_GROUP)
5793 perf_output_read_group(handle, event, enabled, running);
5795 perf_output_read_one(handle, event, enabled, running);
5798 void perf_output_sample(struct perf_output_handle *handle,
5799 struct perf_event_header *header,
5800 struct perf_sample_data *data,
5801 struct perf_event *event)
5803 u64 sample_type = data->type;
5805 perf_output_put(handle, *header);
5807 if (sample_type & PERF_SAMPLE_IDENTIFIER)
5808 perf_output_put(handle, data->id);
5810 if (sample_type & PERF_SAMPLE_IP)
5811 perf_output_put(handle, data->ip);
5813 if (sample_type & PERF_SAMPLE_TID)
5814 perf_output_put(handle, data->tid_entry);
5816 if (sample_type & PERF_SAMPLE_TIME)
5817 perf_output_put(handle, data->time);
5819 if (sample_type & PERF_SAMPLE_ADDR)
5820 perf_output_put(handle, data->addr);
5822 if (sample_type & PERF_SAMPLE_ID)
5823 perf_output_put(handle, data->id);
5825 if (sample_type & PERF_SAMPLE_STREAM_ID)
5826 perf_output_put(handle, data->stream_id);
5828 if (sample_type & PERF_SAMPLE_CPU)
5829 perf_output_put(handle, data->cpu_entry);
5831 if (sample_type & PERF_SAMPLE_PERIOD)
5832 perf_output_put(handle, data->period);
5834 if (sample_type & PERF_SAMPLE_READ)
5835 perf_output_read(handle, event);
5837 if (sample_type & PERF_SAMPLE_CALLCHAIN) {
5838 if (data->callchain) {
5841 if (data->callchain)
5842 size += data->callchain->nr;
5844 size *= sizeof(u64);
5846 __output_copy(handle, data->callchain, size);
5849 perf_output_put(handle, nr);
5853 if (sample_type & PERF_SAMPLE_RAW) {
5854 struct perf_raw_record *raw = data->raw;
5857 struct perf_raw_frag *frag = &raw->frag;
5859 perf_output_put(handle, raw->size);
5862 __output_custom(handle, frag->copy,
5863 frag->data, frag->size);
5865 __output_copy(handle, frag->data,
5868 if (perf_raw_frag_last(frag))
5873 __output_skip(handle, NULL, frag->pad);
5879 .size = sizeof(u32),
5882 perf_output_put(handle, raw);
5886 if (sample_type & PERF_SAMPLE_BRANCH_STACK) {
5887 if (data->br_stack) {
5890 size = data->br_stack->nr
5891 * sizeof(struct perf_branch_entry);
5893 perf_output_put(handle, data->br_stack->nr);
5894 perf_output_copy(handle, data->br_stack->entries, size);
5897 * we always store at least the value of nr
5900 perf_output_put(handle, nr);
5904 if (sample_type & PERF_SAMPLE_REGS_USER) {
5905 u64 abi = data->regs_user.abi;
5908 * If there are no regs to dump, notice it through
5909 * first u64 being zero (PERF_SAMPLE_REGS_ABI_NONE).
5911 perf_output_put(handle, abi);
5914 u64 mask = event->attr.sample_regs_user;
5915 perf_output_sample_regs(handle,
5916 data->regs_user.regs,
5921 if (sample_type & PERF_SAMPLE_STACK_USER) {
5922 perf_output_sample_ustack(handle,
5923 data->stack_user_size,
5924 data->regs_user.regs);
5927 if (sample_type & PERF_SAMPLE_WEIGHT)
5928 perf_output_put(handle, data->weight);
5930 if (sample_type & PERF_SAMPLE_DATA_SRC)
5931 perf_output_put(handle, data->data_src.val);
5933 if (sample_type & PERF_SAMPLE_TRANSACTION)
5934 perf_output_put(handle, data->txn);
5936 if (sample_type & PERF_SAMPLE_REGS_INTR) {
5937 u64 abi = data->regs_intr.abi;
5939 * If there are no regs to dump, notice it through
5940 * first u64 being zero (PERF_SAMPLE_REGS_ABI_NONE).
5942 perf_output_put(handle, abi);
5945 u64 mask = event->attr.sample_regs_intr;
5947 perf_output_sample_regs(handle,
5948 data->regs_intr.regs,
5953 if (!event->attr.watermark) {
5954 int wakeup_events = event->attr.wakeup_events;
5956 if (wakeup_events) {
5957 struct ring_buffer *rb = handle->rb;
5958 int events = local_inc_return(&rb->events);
5960 if (events >= wakeup_events) {
5961 local_sub(wakeup_events, &rb->events);
5962 local_inc(&rb->wakeup);
5968 void perf_prepare_sample(struct perf_event_header *header,
5969 struct perf_sample_data *data,
5970 struct perf_event *event,
5971 struct pt_regs *regs)
5973 u64 sample_type = event->attr.sample_type;
5975 header->type = PERF_RECORD_SAMPLE;
5976 header->size = sizeof(*header) + event->header_size;
5979 header->misc |= perf_misc_flags(regs);
5981 __perf_event_header__init_id(header, data, event);
5983 if (sample_type & PERF_SAMPLE_IP)
5984 data->ip = perf_instruction_pointer(regs);
5986 if (sample_type & PERF_SAMPLE_CALLCHAIN) {
5989 data->callchain = perf_callchain(event, regs);
5991 if (data->callchain)
5992 size += data->callchain->nr;
5994 header->size += size * sizeof(u64);
5997 if (sample_type & PERF_SAMPLE_RAW) {
5998 struct perf_raw_record *raw = data->raw;
6002 struct perf_raw_frag *frag = &raw->frag;
6007 if (perf_raw_frag_last(frag))
6012 size = round_up(sum + sizeof(u32), sizeof(u64));
6013 raw->size = size - sizeof(u32);
6014 frag->pad = raw->size - sum;
6019 header->size += size;
6022 if (sample_type & PERF_SAMPLE_BRANCH_STACK) {
6023 int size = sizeof(u64); /* nr */
6024 if (data->br_stack) {
6025 size += data->br_stack->nr
6026 * sizeof(struct perf_branch_entry);
6028 header->size += size;
6031 if (sample_type & (PERF_SAMPLE_REGS_USER | PERF_SAMPLE_STACK_USER))
6032 perf_sample_regs_user(&data->regs_user, regs,
6033 &data->regs_user_copy);
6035 if (sample_type & PERF_SAMPLE_REGS_USER) {
6036 /* regs dump ABI info */
6037 int size = sizeof(u64);
6039 if (data->regs_user.regs) {
6040 u64 mask = event->attr.sample_regs_user;
6041 size += hweight64(mask) * sizeof(u64);
6044 header->size += size;
6047 if (sample_type & PERF_SAMPLE_STACK_USER) {
6049 * Either we need PERF_SAMPLE_STACK_USER bit to be allways
6050 * processed as the last one or have additional check added
6051 * in case new sample type is added, because we could eat
6052 * up the rest of the sample size.
6054 u16 stack_size = event->attr.sample_stack_user;
6055 u16 size = sizeof(u64);
6057 stack_size = perf_sample_ustack_size(stack_size, header->size,
6058 data->regs_user.regs);
6061 * If there is something to dump, add space for the dump
6062 * itself and for the field that tells the dynamic size,
6063 * which is how many have been actually dumped.
6066 size += sizeof(u64) + stack_size;
6068 data->stack_user_size = stack_size;
6069 header->size += size;
6072 if (sample_type & PERF_SAMPLE_REGS_INTR) {
6073 /* regs dump ABI info */
6074 int size = sizeof(u64);
6076 perf_sample_regs_intr(&data->regs_intr, regs);
6078 if (data->regs_intr.regs) {
6079 u64 mask = event->attr.sample_regs_intr;
6081 size += hweight64(mask) * sizeof(u64);
6084 header->size += size;
6088 static void __always_inline
6089 __perf_event_output(struct perf_event *event,
6090 struct perf_sample_data *data,
6091 struct pt_regs *regs,
6092 int (*output_begin)(struct perf_output_handle *,
6093 struct perf_event *,
6096 struct perf_output_handle handle;
6097 struct perf_event_header header;
6099 /* protect the callchain buffers */
6102 perf_prepare_sample(&header, data, event, regs);
6104 if (output_begin(&handle, event, header.size))
6107 perf_output_sample(&handle, &header, data, event);
6109 perf_output_end(&handle);
6116 perf_event_output_forward(struct perf_event *event,
6117 struct perf_sample_data *data,
6118 struct pt_regs *regs)
6120 __perf_event_output(event, data, regs, perf_output_begin_forward);
6124 perf_event_output_backward(struct perf_event *event,
6125 struct perf_sample_data *data,
6126 struct pt_regs *regs)
6128 __perf_event_output(event, data, regs, perf_output_begin_backward);
6132 perf_event_output(struct perf_event *event,
6133 struct perf_sample_data *data,
6134 struct pt_regs *regs)
6136 __perf_event_output(event, data, regs, perf_output_begin);
6143 struct perf_read_event {
6144 struct perf_event_header header;
6151 perf_event_read_event(struct perf_event *event,
6152 struct task_struct *task)
6154 struct perf_output_handle handle;
6155 struct perf_sample_data sample;
6156 struct perf_read_event read_event = {
6158 .type = PERF_RECORD_READ,
6160 .size = sizeof(read_event) + event->read_size,
6162 .pid = perf_event_pid(event, task),
6163 .tid = perf_event_tid(event, task),
6167 perf_event_header__init_id(&read_event.header, &sample, event);
6168 ret = perf_output_begin(&handle, event, read_event.header.size);
6172 perf_output_put(&handle, read_event);
6173 perf_output_read(&handle, event);
6174 perf_event__output_id_sample(event, &handle, &sample);
6176 perf_output_end(&handle);
6179 typedef void (perf_iterate_f)(struct perf_event *event, void *data);
6182 perf_iterate_ctx(struct perf_event_context *ctx,
6183 perf_iterate_f output,
6184 void *data, bool all)
6186 struct perf_event *event;
6188 list_for_each_entry_rcu(event, &ctx->event_list, event_entry) {
6190 if (event->state < PERF_EVENT_STATE_INACTIVE)
6192 if (!event_filter_match(event))
6196 output(event, data);
6200 static void perf_iterate_sb_cpu(perf_iterate_f output, void *data)
6202 struct pmu_event_list *pel = this_cpu_ptr(&pmu_sb_events);
6203 struct perf_event *event;
6205 list_for_each_entry_rcu(event, &pel->list, sb_list) {
6207 * Skip events that are not fully formed yet; ensure that
6208 * if we observe event->ctx, both event and ctx will be
6209 * complete enough. See perf_install_in_context().
6211 if (!smp_load_acquire(&event->ctx))
6214 if (event->state < PERF_EVENT_STATE_INACTIVE)
6216 if (!event_filter_match(event))
6218 output(event, data);
6223 * Iterate all events that need to receive side-band events.
6225 * For new callers; ensure that account_pmu_sb_event() includes
6226 * your event, otherwise it might not get delivered.
6229 perf_iterate_sb(perf_iterate_f output, void *data,
6230 struct perf_event_context *task_ctx)
6232 struct perf_event_context *ctx;
6239 * If we have task_ctx != NULL we only notify the task context itself.
6240 * The task_ctx is set only for EXIT events before releasing task
6244 perf_iterate_ctx(task_ctx, output, data, false);
6248 perf_iterate_sb_cpu(output, data);
6250 for_each_task_context_nr(ctxn) {
6251 ctx = rcu_dereference(current->perf_event_ctxp[ctxn]);
6253 perf_iterate_ctx(ctx, output, data, false);
6261 * Clear all file-based filters at exec, they'll have to be
6262 * re-instated when/if these objects are mmapped again.
6264 static void perf_event_addr_filters_exec(struct perf_event *event, void *data)
6266 struct perf_addr_filters_head *ifh = perf_event_addr_filters(event);
6267 struct perf_addr_filter *filter;
6268 unsigned int restart = 0, count = 0;
6269 unsigned long flags;
6271 if (!has_addr_filter(event))
6274 raw_spin_lock_irqsave(&ifh->lock, flags);
6275 list_for_each_entry(filter, &ifh->list, entry) {
6276 if (filter->inode) {
6277 event->addr_filters_offs[count] = 0;
6285 event->addr_filters_gen++;
6286 raw_spin_unlock_irqrestore(&ifh->lock, flags);
6289 perf_event_stop(event, 1);
6292 void perf_event_exec(void)
6294 struct perf_event_context *ctx;
6298 for_each_task_context_nr(ctxn) {
6299 ctx = current->perf_event_ctxp[ctxn];
6303 perf_event_enable_on_exec(ctxn);
6305 perf_iterate_ctx(ctx, perf_event_addr_filters_exec, NULL,
6311 struct remote_output {
6312 struct ring_buffer *rb;
6316 static void __perf_event_output_stop(struct perf_event *event, void *data)
6318 struct perf_event *parent = event->parent;
6319 struct remote_output *ro = data;
6320 struct ring_buffer *rb = ro->rb;
6321 struct stop_event_data sd = {
6325 if (!has_aux(event))
6332 * In case of inheritance, it will be the parent that links to the
6333 * ring-buffer, but it will be the child that's actually using it.
6335 * We are using event::rb to determine if the event should be stopped,
6336 * however this may race with ring_buffer_attach() (through set_output),
6337 * which will make us skip the event that actually needs to be stopped.
6338 * So ring_buffer_attach() has to stop an aux event before re-assigning
6341 if (rcu_dereference(parent->rb) == rb)
6342 ro->err = __perf_event_stop(&sd);
6345 static int __perf_pmu_output_stop(void *info)
6347 struct perf_event *event = info;
6348 struct pmu *pmu = event->pmu;
6349 struct perf_cpu_context *cpuctx = this_cpu_ptr(pmu->pmu_cpu_context);
6350 struct remote_output ro = {
6355 perf_iterate_ctx(&cpuctx->ctx, __perf_event_output_stop, &ro, false);
6356 if (cpuctx->task_ctx)
6357 perf_iterate_ctx(cpuctx->task_ctx, __perf_event_output_stop,
6364 static void perf_pmu_output_stop(struct perf_event *event)
6366 struct perf_event *iter;
6371 list_for_each_entry_rcu(iter, &event->rb->event_list, rb_entry) {
6373 * For per-CPU events, we need to make sure that neither they
6374 * nor their children are running; for cpu==-1 events it's
6375 * sufficient to stop the event itself if it's active, since
6376 * it can't have children.
6380 cpu = READ_ONCE(iter->oncpu);
6385 err = cpu_function_call(cpu, __perf_pmu_output_stop, event);
6386 if (err == -EAGAIN) {
6395 * task tracking -- fork/exit
6397 * enabled by: attr.comm | attr.mmap | attr.mmap2 | attr.mmap_data | attr.task
6400 struct perf_task_event {
6401 struct task_struct *task;
6402 struct perf_event_context *task_ctx;
6405 struct perf_event_header header;
6415 static int perf_event_task_match(struct perf_event *event)
6417 return event->attr.comm || event->attr.mmap ||
6418 event->attr.mmap2 || event->attr.mmap_data ||
6422 static void perf_event_task_output(struct perf_event *event,
6425 struct perf_task_event *task_event = data;
6426 struct perf_output_handle handle;
6427 struct perf_sample_data sample;
6428 struct task_struct *task = task_event->task;
6429 int ret, size = task_event->event_id.header.size;
6431 if (!perf_event_task_match(event))
6434 perf_event_header__init_id(&task_event->event_id.header, &sample, event);
6436 ret = perf_output_begin(&handle, event,
6437 task_event->event_id.header.size);
6441 task_event->event_id.pid = perf_event_pid(event, task);
6442 task_event->event_id.ppid = perf_event_pid(event, current);
6444 task_event->event_id.tid = perf_event_tid(event, task);
6445 task_event->event_id.ptid = perf_event_tid(event, current);
6447 task_event->event_id.time = perf_event_clock(event);
6449 perf_output_put(&handle, task_event->event_id);
6451 perf_event__output_id_sample(event, &handle, &sample);
6453 perf_output_end(&handle);
6455 task_event->event_id.header.size = size;
6458 static void perf_event_task(struct task_struct *task,
6459 struct perf_event_context *task_ctx,
6462 struct perf_task_event task_event;
6464 if (!atomic_read(&nr_comm_events) &&
6465 !atomic_read(&nr_mmap_events) &&
6466 !atomic_read(&nr_task_events))
6469 task_event = (struct perf_task_event){
6471 .task_ctx = task_ctx,
6474 .type = new ? PERF_RECORD_FORK : PERF_RECORD_EXIT,
6476 .size = sizeof(task_event.event_id),
6486 perf_iterate_sb(perf_event_task_output,
6491 void perf_event_fork(struct task_struct *task)
6493 perf_event_task(task, NULL, 1);
6500 struct perf_comm_event {
6501 struct task_struct *task;
6506 struct perf_event_header header;
6513 static int perf_event_comm_match(struct perf_event *event)
6515 return event->attr.comm;
6518 static void perf_event_comm_output(struct perf_event *event,
6521 struct perf_comm_event *comm_event = data;
6522 struct perf_output_handle handle;
6523 struct perf_sample_data sample;
6524 int size = comm_event->event_id.header.size;
6527 if (!perf_event_comm_match(event))
6530 perf_event_header__init_id(&comm_event->event_id.header, &sample, event);
6531 ret = perf_output_begin(&handle, event,
6532 comm_event->event_id.header.size);
6537 comm_event->event_id.pid = perf_event_pid(event, comm_event->task);
6538 comm_event->event_id.tid = perf_event_tid(event, comm_event->task);
6540 perf_output_put(&handle, comm_event->event_id);
6541 __output_copy(&handle, comm_event->comm,
6542 comm_event->comm_size);
6544 perf_event__output_id_sample(event, &handle, &sample);
6546 perf_output_end(&handle);
6548 comm_event->event_id.header.size = size;
6551 static void perf_event_comm_event(struct perf_comm_event *comm_event)
6553 char comm[TASK_COMM_LEN];
6556 memset(comm, 0, sizeof(comm));
6557 strlcpy(comm, comm_event->task->comm, sizeof(comm));
6558 size = ALIGN(strlen(comm)+1, sizeof(u64));
6560 comm_event->comm = comm;
6561 comm_event->comm_size = size;
6563 comm_event->event_id.header.size = sizeof(comm_event->event_id) + size;
6565 perf_iterate_sb(perf_event_comm_output,
6570 void perf_event_comm(struct task_struct *task, bool exec)
6572 struct perf_comm_event comm_event;
6574 if (!atomic_read(&nr_comm_events))
6577 comm_event = (struct perf_comm_event){
6583 .type = PERF_RECORD_COMM,
6584 .misc = exec ? PERF_RECORD_MISC_COMM_EXEC : 0,
6592 perf_event_comm_event(&comm_event);
6599 struct perf_mmap_event {
6600 struct vm_area_struct *vma;
6602 const char *file_name;
6610 struct perf_event_header header;
6620 static int perf_event_mmap_match(struct perf_event *event,
6623 struct perf_mmap_event *mmap_event = data;
6624 struct vm_area_struct *vma = mmap_event->vma;
6625 int executable = vma->vm_flags & VM_EXEC;
6627 return (!executable && event->attr.mmap_data) ||
6628 (executable && (event->attr.mmap || event->attr.mmap2));
6631 static void perf_event_mmap_output(struct perf_event *event,
6634 struct perf_mmap_event *mmap_event = data;
6635 struct perf_output_handle handle;
6636 struct perf_sample_data sample;
6637 int size = mmap_event->event_id.header.size;
6640 if (!perf_event_mmap_match(event, data))
6643 if (event->attr.mmap2) {
6644 mmap_event->event_id.header.type = PERF_RECORD_MMAP2;
6645 mmap_event->event_id.header.size += sizeof(mmap_event->maj);
6646 mmap_event->event_id.header.size += sizeof(mmap_event->min);
6647 mmap_event->event_id.header.size += sizeof(mmap_event->ino);
6648 mmap_event->event_id.header.size += sizeof(mmap_event->ino_generation);
6649 mmap_event->event_id.header.size += sizeof(mmap_event->prot);
6650 mmap_event->event_id.header.size += sizeof(mmap_event->flags);
6653 perf_event_header__init_id(&mmap_event->event_id.header, &sample, event);
6654 ret = perf_output_begin(&handle, event,
6655 mmap_event->event_id.header.size);
6659 mmap_event->event_id.pid = perf_event_pid(event, current);
6660 mmap_event->event_id.tid = perf_event_tid(event, current);
6662 perf_output_put(&handle, mmap_event->event_id);
6664 if (event->attr.mmap2) {
6665 perf_output_put(&handle, mmap_event->maj);
6666 perf_output_put(&handle, mmap_event->min);
6667 perf_output_put(&handle, mmap_event->ino);
6668 perf_output_put(&handle, mmap_event->ino_generation);
6669 perf_output_put(&handle, mmap_event->prot);
6670 perf_output_put(&handle, mmap_event->flags);
6673 __output_copy(&handle, mmap_event->file_name,
6674 mmap_event->file_size);
6676 perf_event__output_id_sample(event, &handle, &sample);
6678 perf_output_end(&handle);
6680 mmap_event->event_id.header.size = size;
6683 static void perf_event_mmap_event(struct perf_mmap_event *mmap_event)
6685 struct vm_area_struct *vma = mmap_event->vma;
6686 struct file *file = vma->vm_file;
6687 int maj = 0, min = 0;
6688 u64 ino = 0, gen = 0;
6689 u32 prot = 0, flags = 0;
6695 if (vma->vm_flags & VM_READ)
6697 if (vma->vm_flags & VM_WRITE)
6699 if (vma->vm_flags & VM_EXEC)
6702 if (vma->vm_flags & VM_MAYSHARE)
6705 flags = MAP_PRIVATE;
6707 if (vma->vm_flags & VM_DENYWRITE)
6708 flags |= MAP_DENYWRITE;
6709 if (vma->vm_flags & VM_MAYEXEC)
6710 flags |= MAP_EXECUTABLE;
6711 if (vma->vm_flags & VM_LOCKED)
6712 flags |= MAP_LOCKED;
6713 if (vma->vm_flags & VM_HUGETLB)
6714 flags |= MAP_HUGETLB;
6717 struct inode *inode;
6720 buf = kmalloc(PATH_MAX, GFP_KERNEL);
6726 * d_path() works from the end of the rb backwards, so we
6727 * need to add enough zero bytes after the string to handle
6728 * the 64bit alignment we do later.
6730 name = file_path(file, buf, PATH_MAX - sizeof(u64));
6735 inode = file_inode(vma->vm_file);
6736 dev = inode->i_sb->s_dev;
6738 gen = inode->i_generation;
6744 if (vma->vm_ops && vma->vm_ops->name) {
6745 name = (char *) vma->vm_ops->name(vma);
6750 name = (char *)arch_vma_name(vma);
6754 if (vma->vm_start <= vma->vm_mm->start_brk &&
6755 vma->vm_end >= vma->vm_mm->brk) {
6759 if (vma->vm_start <= vma->vm_mm->start_stack &&
6760 vma->vm_end >= vma->vm_mm->start_stack) {
6770 strlcpy(tmp, name, sizeof(tmp));
6774 * Since our buffer works in 8 byte units we need to align our string
6775 * size to a multiple of 8. However, we must guarantee the tail end is
6776 * zero'd out to avoid leaking random bits to userspace.
6778 size = strlen(name)+1;
6779 while (!IS_ALIGNED(size, sizeof(u64)))
6780 name[size++] = '\0';
6782 mmap_event->file_name = name;
6783 mmap_event->file_size = size;
6784 mmap_event->maj = maj;
6785 mmap_event->min = min;
6786 mmap_event->ino = ino;
6787 mmap_event->ino_generation = gen;
6788 mmap_event->prot = prot;
6789 mmap_event->flags = flags;
6791 if (!(vma->vm_flags & VM_EXEC))
6792 mmap_event->event_id.header.misc |= PERF_RECORD_MISC_MMAP_DATA;
6794 mmap_event->event_id.header.size = sizeof(mmap_event->event_id) + size;
6796 perf_iterate_sb(perf_event_mmap_output,
6804 * Check whether inode and address range match filter criteria.
6806 static bool perf_addr_filter_match(struct perf_addr_filter *filter,
6807 struct file *file, unsigned long offset,
6810 if (filter->inode != file_inode(file))
6813 if (filter->offset > offset + size)
6816 if (filter->offset + filter->size < offset)
6822 static void __perf_addr_filters_adjust(struct perf_event *event, void *data)
6824 struct perf_addr_filters_head *ifh = perf_event_addr_filters(event);
6825 struct vm_area_struct *vma = data;
6826 unsigned long off = vma->vm_pgoff << PAGE_SHIFT, flags;
6827 struct file *file = vma->vm_file;
6828 struct perf_addr_filter *filter;
6829 unsigned int restart = 0, count = 0;
6831 if (!has_addr_filter(event))
6837 raw_spin_lock_irqsave(&ifh->lock, flags);
6838 list_for_each_entry(filter, &ifh->list, entry) {
6839 if (perf_addr_filter_match(filter, file, off,
6840 vma->vm_end - vma->vm_start)) {
6841 event->addr_filters_offs[count] = vma->vm_start;
6849 event->addr_filters_gen++;
6850 raw_spin_unlock_irqrestore(&ifh->lock, flags);
6853 perf_event_stop(event, 1);
6857 * Adjust all task's events' filters to the new vma
6859 static void perf_addr_filters_adjust(struct vm_area_struct *vma)
6861 struct perf_event_context *ctx;
6865 * Data tracing isn't supported yet and as such there is no need
6866 * to keep track of anything that isn't related to executable code:
6868 if (!(vma->vm_flags & VM_EXEC))
6872 for_each_task_context_nr(ctxn) {
6873 ctx = rcu_dereference(current->perf_event_ctxp[ctxn]);
6877 perf_iterate_ctx(ctx, __perf_addr_filters_adjust, vma, true);
6882 void perf_event_mmap(struct vm_area_struct *vma)
6884 struct perf_mmap_event mmap_event;
6886 if (!atomic_read(&nr_mmap_events))
6889 mmap_event = (struct perf_mmap_event){
6895 .type = PERF_RECORD_MMAP,
6896 .misc = PERF_RECORD_MISC_USER,
6901 .start = vma->vm_start,
6902 .len = vma->vm_end - vma->vm_start,
6903 .pgoff = (u64)vma->vm_pgoff << PAGE_SHIFT,
6905 /* .maj (attr_mmap2 only) */
6906 /* .min (attr_mmap2 only) */
6907 /* .ino (attr_mmap2 only) */
6908 /* .ino_generation (attr_mmap2 only) */
6909 /* .prot (attr_mmap2 only) */
6910 /* .flags (attr_mmap2 only) */
6913 perf_addr_filters_adjust(vma);
6914 perf_event_mmap_event(&mmap_event);
6917 void perf_event_aux_event(struct perf_event *event, unsigned long head,
6918 unsigned long size, u64 flags)
6920 struct perf_output_handle handle;
6921 struct perf_sample_data sample;
6922 struct perf_aux_event {
6923 struct perf_event_header header;
6929 .type = PERF_RECORD_AUX,
6931 .size = sizeof(rec),
6939 perf_event_header__init_id(&rec.header, &sample, event);
6940 ret = perf_output_begin(&handle, event, rec.header.size);
6945 perf_output_put(&handle, rec);
6946 perf_event__output_id_sample(event, &handle, &sample);
6948 perf_output_end(&handle);
6952 * Lost/dropped samples logging
6954 void perf_log_lost_samples(struct perf_event *event, u64 lost)
6956 struct perf_output_handle handle;
6957 struct perf_sample_data sample;
6961 struct perf_event_header header;
6963 } lost_samples_event = {
6965 .type = PERF_RECORD_LOST_SAMPLES,
6967 .size = sizeof(lost_samples_event),
6972 perf_event_header__init_id(&lost_samples_event.header, &sample, event);
6974 ret = perf_output_begin(&handle, event,
6975 lost_samples_event.header.size);
6979 perf_output_put(&handle, lost_samples_event);
6980 perf_event__output_id_sample(event, &handle, &sample);
6981 perf_output_end(&handle);
6985 * context_switch tracking
6988 struct perf_switch_event {
6989 struct task_struct *task;
6990 struct task_struct *next_prev;
6993 struct perf_event_header header;
6999 static int perf_event_switch_match(struct perf_event *event)
7001 return event->attr.context_switch;
7004 static void perf_event_switch_output(struct perf_event *event, void *data)
7006 struct perf_switch_event *se = data;
7007 struct perf_output_handle handle;
7008 struct perf_sample_data sample;
7011 if (!perf_event_switch_match(event))
7014 /* Only CPU-wide events are allowed to see next/prev pid/tid */
7015 if (event->ctx->task) {
7016 se->event_id.header.type = PERF_RECORD_SWITCH;
7017 se->event_id.header.size = sizeof(se->event_id.header);
7019 se->event_id.header.type = PERF_RECORD_SWITCH_CPU_WIDE;
7020 se->event_id.header.size = sizeof(se->event_id);
7021 se->event_id.next_prev_pid =
7022 perf_event_pid(event, se->next_prev);
7023 se->event_id.next_prev_tid =
7024 perf_event_tid(event, se->next_prev);
7027 perf_event_header__init_id(&se->event_id.header, &sample, event);
7029 ret = perf_output_begin(&handle, event, se->event_id.header.size);
7033 if (event->ctx->task)
7034 perf_output_put(&handle, se->event_id.header);
7036 perf_output_put(&handle, se->event_id);
7038 perf_event__output_id_sample(event, &handle, &sample);
7040 perf_output_end(&handle);
7043 static void perf_event_switch(struct task_struct *task,
7044 struct task_struct *next_prev, bool sched_in)
7046 struct perf_switch_event switch_event;
7048 /* N.B. caller checks nr_switch_events != 0 */
7050 switch_event = (struct perf_switch_event){
7052 .next_prev = next_prev,
7056 .misc = sched_in ? 0 : PERF_RECORD_MISC_SWITCH_OUT,
7059 /* .next_prev_pid */
7060 /* .next_prev_tid */
7064 perf_iterate_sb(perf_event_switch_output,
7070 * IRQ throttle logging
7073 static void perf_log_throttle(struct perf_event *event, int enable)
7075 struct perf_output_handle handle;
7076 struct perf_sample_data sample;
7080 struct perf_event_header header;
7084 } throttle_event = {
7086 .type = PERF_RECORD_THROTTLE,
7088 .size = sizeof(throttle_event),
7090 .time = perf_event_clock(event),
7091 .id = primary_event_id(event),
7092 .stream_id = event->id,
7096 throttle_event.header.type = PERF_RECORD_UNTHROTTLE;
7098 perf_event_header__init_id(&throttle_event.header, &sample, event);
7100 ret = perf_output_begin(&handle, event,
7101 throttle_event.header.size);
7105 perf_output_put(&handle, throttle_event);
7106 perf_event__output_id_sample(event, &handle, &sample);
7107 perf_output_end(&handle);
7110 static void perf_log_itrace_start(struct perf_event *event)
7112 struct perf_output_handle handle;
7113 struct perf_sample_data sample;
7114 struct perf_aux_event {
7115 struct perf_event_header header;
7122 event = event->parent;
7124 if (!(event->pmu->capabilities & PERF_PMU_CAP_ITRACE) ||
7125 event->hw.itrace_started)
7128 rec.header.type = PERF_RECORD_ITRACE_START;
7129 rec.header.misc = 0;
7130 rec.header.size = sizeof(rec);
7131 rec.pid = perf_event_pid(event, current);
7132 rec.tid = perf_event_tid(event, current);
7134 perf_event_header__init_id(&rec.header, &sample, event);
7135 ret = perf_output_begin(&handle, event, rec.header.size);
7140 perf_output_put(&handle, rec);
7141 perf_event__output_id_sample(event, &handle, &sample);
7143 perf_output_end(&handle);
7147 __perf_event_account_interrupt(struct perf_event *event, int throttle)
7149 struct hw_perf_event *hwc = &event->hw;
7153 seq = __this_cpu_read(perf_throttled_seq);
7154 if (seq != hwc->interrupts_seq) {
7155 hwc->interrupts_seq = seq;
7156 hwc->interrupts = 1;
7159 if (unlikely(throttle
7160 && hwc->interrupts >= max_samples_per_tick)) {
7161 __this_cpu_inc(perf_throttled_count);
7162 tick_dep_set_cpu(smp_processor_id(), TICK_DEP_BIT_PERF_EVENTS);
7163 hwc->interrupts = MAX_INTERRUPTS;
7164 perf_log_throttle(event, 0);
7169 if (event->attr.freq) {
7170 u64 now = perf_clock();
7171 s64 delta = now - hwc->freq_time_stamp;
7173 hwc->freq_time_stamp = now;
7175 if (delta > 0 && delta < 2*TICK_NSEC)
7176 perf_adjust_period(event, delta, hwc->last_period, true);
7182 int perf_event_account_interrupt(struct perf_event *event)
7184 return __perf_event_account_interrupt(event, 1);
7188 * Generic event overflow handling, sampling.
7191 static int __perf_event_overflow(struct perf_event *event,
7192 int throttle, struct perf_sample_data *data,
7193 struct pt_regs *regs)
7195 int events = atomic_read(&event->event_limit);
7199 * Non-sampling counters might still use the PMI to fold short
7200 * hardware counters, ignore those.
7202 if (unlikely(!is_sampling_event(event)))
7205 ret = __perf_event_account_interrupt(event, throttle);
7208 * XXX event_limit might not quite work as expected on inherited
7212 event->pending_kill = POLL_IN;
7213 if (events && atomic_dec_and_test(&event->event_limit)) {
7215 event->pending_kill = POLL_HUP;
7217 perf_event_disable_inatomic(event);
7220 READ_ONCE(event->overflow_handler)(event, data, regs);
7222 if (*perf_event_fasync(event) && event->pending_kill) {
7223 event->pending_wakeup = 1;
7224 irq_work_queue(&event->pending);
7230 int perf_event_overflow(struct perf_event *event,
7231 struct perf_sample_data *data,
7232 struct pt_regs *regs)
7234 return __perf_event_overflow(event, 1, data, regs);
7238 * Generic software event infrastructure
7241 struct swevent_htable {
7242 struct swevent_hlist *swevent_hlist;
7243 struct mutex hlist_mutex;
7246 /* Recursion avoidance in each contexts */
7247 int recursion[PERF_NR_CONTEXTS];
7250 static DEFINE_PER_CPU(struct swevent_htable, swevent_htable);
7253 * We directly increment event->count and keep a second value in
7254 * event->hw.period_left to count intervals. This period event
7255 * is kept in the range [-sample_period, 0] so that we can use the
7259 u64 perf_swevent_set_period(struct perf_event *event)
7261 struct hw_perf_event *hwc = &event->hw;
7262 u64 period = hwc->last_period;
7266 hwc->last_period = hwc->sample_period;
7269 old = val = local64_read(&hwc->period_left);
7273 nr = div64_u64(period + val, period);
7274 offset = nr * period;
7276 if (local64_cmpxchg(&hwc->period_left, old, val) != old)
7282 static void perf_swevent_overflow(struct perf_event *event, u64 overflow,
7283 struct perf_sample_data *data,
7284 struct pt_regs *regs)
7286 struct hw_perf_event *hwc = &event->hw;
7290 overflow = perf_swevent_set_period(event);
7292 if (hwc->interrupts == MAX_INTERRUPTS)
7295 for (; overflow; overflow--) {
7296 if (__perf_event_overflow(event, throttle,
7299 * We inhibit the overflow from happening when
7300 * hwc->interrupts == MAX_INTERRUPTS.
7308 static void perf_swevent_event(struct perf_event *event, u64 nr,
7309 struct perf_sample_data *data,
7310 struct pt_regs *regs)
7312 struct hw_perf_event *hwc = &event->hw;
7314 local64_add(nr, &event->count);
7319 if (!is_sampling_event(event))
7322 if ((event->attr.sample_type & PERF_SAMPLE_PERIOD) && !event->attr.freq) {
7324 return perf_swevent_overflow(event, 1, data, regs);
7326 data->period = event->hw.last_period;
7328 if (nr == 1 && hwc->sample_period == 1 && !event->attr.freq)
7329 return perf_swevent_overflow(event, 1, data, regs);
7331 if (local64_add_negative(nr, &hwc->period_left))
7334 perf_swevent_overflow(event, 0, data, regs);
7337 static int perf_exclude_event(struct perf_event *event,
7338 struct pt_regs *regs)
7340 if (event->hw.state & PERF_HES_STOPPED)
7344 if (event->attr.exclude_user && user_mode(regs))
7347 if (event->attr.exclude_kernel && !user_mode(regs))
7354 static int perf_swevent_match(struct perf_event *event,
7355 enum perf_type_id type,
7357 struct perf_sample_data *data,
7358 struct pt_regs *regs)
7360 if (event->attr.type != type)
7363 if (event->attr.config != event_id)
7366 if (perf_exclude_event(event, regs))
7372 static inline u64 swevent_hash(u64 type, u32 event_id)
7374 u64 val = event_id | (type << 32);
7376 return hash_64(val, SWEVENT_HLIST_BITS);
7379 static inline struct hlist_head *
7380 __find_swevent_head(struct swevent_hlist *hlist, u64 type, u32 event_id)
7382 u64 hash = swevent_hash(type, event_id);
7384 return &hlist->heads[hash];
7387 /* For the read side: events when they trigger */
7388 static inline struct hlist_head *
7389 find_swevent_head_rcu(struct swevent_htable *swhash, u64 type, u32 event_id)
7391 struct swevent_hlist *hlist;
7393 hlist = rcu_dereference(swhash->swevent_hlist);
7397 return __find_swevent_head(hlist, type, event_id);
7400 /* For the event head insertion and removal in the hlist */
7401 static inline struct hlist_head *
7402 find_swevent_head(struct swevent_htable *swhash, struct perf_event *event)
7404 struct swevent_hlist *hlist;
7405 u32 event_id = event->attr.config;
7406 u64 type = event->attr.type;
7409 * Event scheduling is always serialized against hlist allocation
7410 * and release. Which makes the protected version suitable here.
7411 * The context lock guarantees that.
7413 hlist = rcu_dereference_protected(swhash->swevent_hlist,
7414 lockdep_is_held(&event->ctx->lock));
7418 return __find_swevent_head(hlist, type, event_id);
7421 static void do_perf_sw_event(enum perf_type_id type, u32 event_id,
7423 struct perf_sample_data *data,
7424 struct pt_regs *regs)
7426 struct swevent_htable *swhash = this_cpu_ptr(&swevent_htable);
7427 struct perf_event *event;
7428 struct hlist_head *head;
7431 head = find_swevent_head_rcu(swhash, type, event_id);
7435 hlist_for_each_entry_rcu(event, head, hlist_entry) {
7436 if (perf_swevent_match(event, type, event_id, data, regs))
7437 perf_swevent_event(event, nr, data, regs);
7443 DEFINE_PER_CPU(struct pt_regs, __perf_regs[4]);
7445 int perf_swevent_get_recursion_context(void)
7447 struct swevent_htable *swhash = this_cpu_ptr(&swevent_htable);
7449 return get_recursion_context(swhash->recursion);
7451 EXPORT_SYMBOL_GPL(perf_swevent_get_recursion_context);
7453 void perf_swevent_put_recursion_context(int rctx)
7455 struct swevent_htable *swhash = this_cpu_ptr(&swevent_htable);
7457 put_recursion_context(swhash->recursion, rctx);
7460 void ___perf_sw_event(u32 event_id, u64 nr, struct pt_regs *regs, u64 addr)
7462 struct perf_sample_data data;
7464 if (WARN_ON_ONCE(!regs))
7467 perf_sample_data_init(&data, addr, 0);
7468 do_perf_sw_event(PERF_TYPE_SOFTWARE, event_id, nr, &data, regs);
7471 void __perf_sw_event(u32 event_id, u64 nr, struct pt_regs *regs, u64 addr)
7475 preempt_disable_notrace();
7476 rctx = perf_swevent_get_recursion_context();
7477 if (unlikely(rctx < 0))
7480 ___perf_sw_event(event_id, nr, regs, addr);
7482 perf_swevent_put_recursion_context(rctx);
7484 preempt_enable_notrace();
7487 static void perf_swevent_read(struct perf_event *event)
7491 static int perf_swevent_add(struct perf_event *event, int flags)
7493 struct swevent_htable *swhash = this_cpu_ptr(&swevent_htable);
7494 struct hw_perf_event *hwc = &event->hw;
7495 struct hlist_head *head;
7497 if (is_sampling_event(event)) {
7498 hwc->last_period = hwc->sample_period;
7499 perf_swevent_set_period(event);
7502 hwc->state = !(flags & PERF_EF_START);
7504 head = find_swevent_head(swhash, event);
7505 if (WARN_ON_ONCE(!head))
7508 hlist_add_head_rcu(&event->hlist_entry, head);
7509 perf_event_update_userpage(event);
7514 static void perf_swevent_del(struct perf_event *event, int flags)
7516 hlist_del_rcu(&event->hlist_entry);
7519 static void perf_swevent_start(struct perf_event *event, int flags)
7521 event->hw.state = 0;
7524 static void perf_swevent_stop(struct perf_event *event, int flags)
7526 event->hw.state = PERF_HES_STOPPED;
7529 /* Deref the hlist from the update side */
7530 static inline struct swevent_hlist *
7531 swevent_hlist_deref(struct swevent_htable *swhash)
7533 return rcu_dereference_protected(swhash->swevent_hlist,
7534 lockdep_is_held(&swhash->hlist_mutex));
7537 static void swevent_hlist_release(struct swevent_htable *swhash)
7539 struct swevent_hlist *hlist = swevent_hlist_deref(swhash);
7544 RCU_INIT_POINTER(swhash->swevent_hlist, NULL);
7545 kfree_rcu(hlist, rcu_head);
7548 static void swevent_hlist_put_cpu(int cpu)
7550 struct swevent_htable *swhash = &per_cpu(swevent_htable, cpu);
7552 mutex_lock(&swhash->hlist_mutex);
7554 if (!--swhash->hlist_refcount)
7555 swevent_hlist_release(swhash);
7557 mutex_unlock(&swhash->hlist_mutex);
7560 static void swevent_hlist_put(void)
7564 for_each_possible_cpu(cpu)
7565 swevent_hlist_put_cpu(cpu);
7568 static int swevent_hlist_get_cpu(int cpu)
7570 struct swevent_htable *swhash = &per_cpu(swevent_htable, cpu);
7573 mutex_lock(&swhash->hlist_mutex);
7574 if (!swevent_hlist_deref(swhash) && cpu_online(cpu)) {
7575 struct swevent_hlist *hlist;
7577 hlist = kzalloc(sizeof(*hlist), GFP_KERNEL);
7582 rcu_assign_pointer(swhash->swevent_hlist, hlist);
7584 swhash->hlist_refcount++;
7586 mutex_unlock(&swhash->hlist_mutex);
7591 static int swevent_hlist_get(void)
7593 int err, cpu, failed_cpu;
7596 for_each_possible_cpu(cpu) {
7597 err = swevent_hlist_get_cpu(cpu);
7607 for_each_possible_cpu(cpu) {
7608 if (cpu == failed_cpu)
7610 swevent_hlist_put_cpu(cpu);
7617 struct static_key perf_swevent_enabled[PERF_COUNT_SW_MAX];
7619 static void sw_perf_event_destroy(struct perf_event *event)
7621 u64 event_id = event->attr.config;
7623 WARN_ON(event->parent);
7625 static_key_slow_dec(&perf_swevent_enabled[event_id]);
7626 swevent_hlist_put();
7629 static int perf_swevent_init(struct perf_event *event)
7631 u64 event_id = event->attr.config;
7633 if (event->attr.type != PERF_TYPE_SOFTWARE)
7637 * no branch sampling for software events
7639 if (has_branch_stack(event))
7643 case PERF_COUNT_SW_CPU_CLOCK:
7644 case PERF_COUNT_SW_TASK_CLOCK:
7651 if (event_id >= PERF_COUNT_SW_MAX)
7654 if (!event->parent) {
7657 err = swevent_hlist_get();
7661 static_key_slow_inc(&perf_swevent_enabled[event_id]);
7662 event->destroy = sw_perf_event_destroy;
7668 static struct pmu perf_swevent = {
7669 .task_ctx_nr = perf_sw_context,
7671 .capabilities = PERF_PMU_CAP_NO_NMI,
7673 .event_init = perf_swevent_init,
7674 .add = perf_swevent_add,
7675 .del = perf_swevent_del,
7676 .start = perf_swevent_start,
7677 .stop = perf_swevent_stop,
7678 .read = perf_swevent_read,
7681 #ifdef CONFIG_EVENT_TRACING
7683 static int perf_tp_filter_match(struct perf_event *event,
7684 struct perf_sample_data *data)
7686 void *record = data->raw->frag.data;
7688 /* only top level events have filters set */
7690 event = event->parent;
7692 if (likely(!event->filter) || filter_match_preds(event->filter, record))
7697 static int perf_tp_event_match(struct perf_event *event,
7698 struct perf_sample_data *data,
7699 struct pt_regs *regs)
7701 if (event->hw.state & PERF_HES_STOPPED)
7704 * All tracepoints are from kernel-space.
7706 if (event->attr.exclude_kernel)
7709 if (!perf_tp_filter_match(event, data))
7715 void perf_trace_run_bpf_submit(void *raw_data, int size, int rctx,
7716 struct trace_event_call *call, u64 count,
7717 struct pt_regs *regs, struct hlist_head *head,
7718 struct task_struct *task)
7720 struct bpf_prog *prog = call->prog;
7723 *(struct pt_regs **)raw_data = regs;
7724 if (!trace_call_bpf(prog, raw_data) || hlist_empty(head)) {
7725 perf_swevent_put_recursion_context(rctx);
7729 perf_tp_event(call->event.type, count, raw_data, size, regs, head,
7732 EXPORT_SYMBOL_GPL(perf_trace_run_bpf_submit);
7734 void perf_tp_event(u16 event_type, u64 count, void *record, int entry_size,
7735 struct pt_regs *regs, struct hlist_head *head, int rctx,
7736 struct task_struct *task)
7738 struct perf_sample_data data;
7739 struct perf_event *event;
7741 struct perf_raw_record raw = {
7748 perf_sample_data_init(&data, 0, 0);
7751 perf_trace_buf_update(record, event_type);
7753 hlist_for_each_entry_rcu(event, head, hlist_entry) {
7754 if (perf_tp_event_match(event, &data, regs))
7755 perf_swevent_event(event, count, &data, regs);
7759 * If we got specified a target task, also iterate its context and
7760 * deliver this event there too.
7762 if (task && task != current) {
7763 struct perf_event_context *ctx;
7764 struct trace_entry *entry = record;
7767 ctx = rcu_dereference(task->perf_event_ctxp[perf_sw_context]);
7771 list_for_each_entry_rcu(event, &ctx->event_list, event_entry) {
7772 if (event->attr.type != PERF_TYPE_TRACEPOINT)
7774 if (event->attr.config != entry->type)
7776 if (perf_tp_event_match(event, &data, regs))
7777 perf_swevent_event(event, count, &data, regs);
7783 perf_swevent_put_recursion_context(rctx);
7785 EXPORT_SYMBOL_GPL(perf_tp_event);
7787 static void tp_perf_event_destroy(struct perf_event *event)
7789 perf_trace_destroy(event);
7792 static int perf_tp_event_init(struct perf_event *event)
7796 if (event->attr.type != PERF_TYPE_TRACEPOINT)
7800 * no branch sampling for tracepoint events
7802 if (has_branch_stack(event))
7805 err = perf_trace_init(event);
7809 event->destroy = tp_perf_event_destroy;
7814 static struct pmu perf_tracepoint = {
7815 .task_ctx_nr = perf_sw_context,
7817 .event_init = perf_tp_event_init,
7818 .add = perf_trace_add,
7819 .del = perf_trace_del,
7820 .start = perf_swevent_start,
7821 .stop = perf_swevent_stop,
7822 .read = perf_swevent_read,
7825 static inline void perf_tp_register(void)
7827 perf_pmu_register(&perf_tracepoint, "tracepoint", PERF_TYPE_TRACEPOINT);
7830 static void perf_event_free_filter(struct perf_event *event)
7832 ftrace_profile_free_filter(event);
7835 #ifdef CONFIG_BPF_SYSCALL
7836 static void bpf_overflow_handler(struct perf_event *event,
7837 struct perf_sample_data *data,
7838 struct pt_regs *regs)
7840 struct bpf_perf_event_data_kern ctx = {
7847 if (unlikely(__this_cpu_inc_return(bpf_prog_active) != 1))
7850 ret = BPF_PROG_RUN(event->prog, &ctx);
7853 __this_cpu_dec(bpf_prog_active);
7858 event->orig_overflow_handler(event, data, regs);
7861 static int perf_event_set_bpf_handler(struct perf_event *event, u32 prog_fd)
7863 struct bpf_prog *prog;
7865 if (event->overflow_handler_context)
7866 /* hw breakpoint or kernel counter */
7872 prog = bpf_prog_get_type(prog_fd, BPF_PROG_TYPE_PERF_EVENT);
7874 return PTR_ERR(prog);
7877 event->orig_overflow_handler = READ_ONCE(event->overflow_handler);
7878 WRITE_ONCE(event->overflow_handler, bpf_overflow_handler);
7882 static void perf_event_free_bpf_handler(struct perf_event *event)
7884 struct bpf_prog *prog = event->prog;
7889 WRITE_ONCE(event->overflow_handler, event->orig_overflow_handler);
7894 static int perf_event_set_bpf_handler(struct perf_event *event, u32 prog_fd)
7898 static void perf_event_free_bpf_handler(struct perf_event *event)
7903 static int perf_event_set_bpf_prog(struct perf_event *event, u32 prog_fd)
7905 bool is_kprobe, is_tracepoint;
7906 struct bpf_prog *prog;
7908 if (event->attr.type == PERF_TYPE_HARDWARE ||
7909 event->attr.type == PERF_TYPE_SOFTWARE)
7910 return perf_event_set_bpf_handler(event, prog_fd);
7912 if (event->attr.type != PERF_TYPE_TRACEPOINT)
7915 if (event->tp_event->prog)
7918 is_kprobe = event->tp_event->flags & TRACE_EVENT_FL_UKPROBE;
7919 is_tracepoint = event->tp_event->flags & TRACE_EVENT_FL_TRACEPOINT;
7920 if (!is_kprobe && !is_tracepoint)
7921 /* bpf programs can only be attached to u/kprobe or tracepoint */
7924 prog = bpf_prog_get(prog_fd);
7926 return PTR_ERR(prog);
7928 if ((is_kprobe && prog->type != BPF_PROG_TYPE_KPROBE) ||
7929 (is_tracepoint && prog->type != BPF_PROG_TYPE_TRACEPOINT)) {
7930 /* valid fd, but invalid bpf program type */
7935 if (is_tracepoint) {
7936 int off = trace_event_get_offsets(event->tp_event);
7938 if (prog->aux->max_ctx_offset > off) {
7943 event->tp_event->prog = prog;
7948 static void perf_event_free_bpf_prog(struct perf_event *event)
7950 struct bpf_prog *prog;
7952 perf_event_free_bpf_handler(event);
7954 if (!event->tp_event)
7957 prog = event->tp_event->prog;
7959 event->tp_event->prog = NULL;
7966 static inline void perf_tp_register(void)
7970 static void perf_event_free_filter(struct perf_event *event)
7974 static int perf_event_set_bpf_prog(struct perf_event *event, u32 prog_fd)
7979 static void perf_event_free_bpf_prog(struct perf_event *event)
7982 #endif /* CONFIG_EVENT_TRACING */
7984 #ifdef CONFIG_HAVE_HW_BREAKPOINT
7985 void perf_bp_event(struct perf_event *bp, void *data)
7987 struct perf_sample_data sample;
7988 struct pt_regs *regs = data;
7990 perf_sample_data_init(&sample, bp->attr.bp_addr, 0);
7992 if (!bp->hw.state && !perf_exclude_event(bp, regs))
7993 perf_swevent_event(bp, 1, &sample, regs);
7998 * Allocate a new address filter
8000 static struct perf_addr_filter *
8001 perf_addr_filter_new(struct perf_event *event, struct list_head *filters)
8003 int node = cpu_to_node(event->cpu == -1 ? 0 : event->cpu);
8004 struct perf_addr_filter *filter;
8006 filter = kzalloc_node(sizeof(*filter), GFP_KERNEL, node);
8010 INIT_LIST_HEAD(&filter->entry);
8011 list_add_tail(&filter->entry, filters);
8016 static void free_filters_list(struct list_head *filters)
8018 struct perf_addr_filter *filter, *iter;
8020 list_for_each_entry_safe(filter, iter, filters, entry) {
8022 iput(filter->inode);
8023 list_del(&filter->entry);
8029 * Free existing address filters and optionally install new ones
8031 static void perf_addr_filters_splice(struct perf_event *event,
8032 struct list_head *head)
8034 unsigned long flags;
8037 if (!has_addr_filter(event))
8040 /* don't bother with children, they don't have their own filters */
8044 raw_spin_lock_irqsave(&event->addr_filters.lock, flags);
8046 list_splice_init(&event->addr_filters.list, &list);
8048 list_splice(head, &event->addr_filters.list);
8050 raw_spin_unlock_irqrestore(&event->addr_filters.lock, flags);
8052 free_filters_list(&list);
8056 * Scan through mm's vmas and see if one of them matches the
8057 * @filter; if so, adjust filter's address range.
8058 * Called with mm::mmap_sem down for reading.
8060 static unsigned long perf_addr_filter_apply(struct perf_addr_filter *filter,
8061 struct mm_struct *mm)
8063 struct vm_area_struct *vma;
8065 for (vma = mm->mmap; vma; vma = vma->vm_next) {
8066 struct file *file = vma->vm_file;
8067 unsigned long off = vma->vm_pgoff << PAGE_SHIFT;
8068 unsigned long vma_size = vma->vm_end - vma->vm_start;
8073 if (!perf_addr_filter_match(filter, file, off, vma_size))
8076 return vma->vm_start;
8083 * Update event's address range filters based on the
8084 * task's existing mappings, if any.
8086 static void perf_event_addr_filters_apply(struct perf_event *event)
8088 struct perf_addr_filters_head *ifh = perf_event_addr_filters(event);
8089 struct task_struct *task = READ_ONCE(event->ctx->task);
8090 struct perf_addr_filter *filter;
8091 struct mm_struct *mm = NULL;
8092 unsigned int count = 0;
8093 unsigned long flags;
8096 * We may observe TASK_TOMBSTONE, which means that the event tear-down
8097 * will stop on the parent's child_mutex that our caller is also holding
8099 if (task == TASK_TOMBSTONE)
8102 if (!ifh->nr_file_filters)
8105 mm = get_task_mm(event->ctx->task);
8109 down_read(&mm->mmap_sem);
8111 raw_spin_lock_irqsave(&ifh->lock, flags);
8112 list_for_each_entry(filter, &ifh->list, entry) {
8113 event->addr_filters_offs[count] = 0;
8116 * Adjust base offset if the filter is associated to a binary
8117 * that needs to be mapped:
8120 event->addr_filters_offs[count] =
8121 perf_addr_filter_apply(filter, mm);
8126 event->addr_filters_gen++;
8127 raw_spin_unlock_irqrestore(&ifh->lock, flags);
8129 up_read(&mm->mmap_sem);
8134 perf_event_stop(event, 1);
8138 * Address range filtering: limiting the data to certain
8139 * instruction address ranges. Filters are ioctl()ed to us from
8140 * userspace as ascii strings.
8142 * Filter string format:
8145 * where ACTION is one of the
8146 * * "filter": limit the trace to this region
8147 * * "start": start tracing from this address
8148 * * "stop": stop tracing at this address/region;
8150 * * for kernel addresses: <start address>[/<size>]
8151 * * for object files: <start address>[/<size>]@</path/to/object/file>
8153 * if <size> is not specified, the range is treated as a single address.
8167 IF_STATE_ACTION = 0,
8172 static const match_table_t if_tokens = {
8173 { IF_ACT_FILTER, "filter" },
8174 { IF_ACT_START, "start" },
8175 { IF_ACT_STOP, "stop" },
8176 { IF_SRC_FILE, "%u/%u@%s" },
8177 { IF_SRC_KERNEL, "%u/%u" },
8178 { IF_SRC_FILEADDR, "%u@%s" },
8179 { IF_SRC_KERNELADDR, "%u" },
8180 { IF_ACT_NONE, NULL },
8184 * Address filter string parser
8187 perf_event_parse_addr_filter(struct perf_event *event, char *fstr,
8188 struct list_head *filters)
8190 struct perf_addr_filter *filter = NULL;
8191 char *start, *orig, *filename = NULL;
8193 substring_t args[MAX_OPT_ARGS];
8194 int state = IF_STATE_ACTION, token;
8195 unsigned int kernel = 0;
8198 orig = fstr = kstrdup(fstr, GFP_KERNEL);
8202 while ((start = strsep(&fstr, " ,\n")) != NULL) {
8208 /* filter definition begins */
8209 if (state == IF_STATE_ACTION) {
8210 filter = perf_addr_filter_new(event, filters);
8215 token = match_token(start, if_tokens, args);
8222 if (state != IF_STATE_ACTION)
8225 state = IF_STATE_SOURCE;
8228 case IF_SRC_KERNELADDR:
8232 case IF_SRC_FILEADDR:
8234 if (state != IF_STATE_SOURCE)
8237 if (token == IF_SRC_FILE || token == IF_SRC_KERNEL)
8241 ret = kstrtoul(args[0].from, 0, &filter->offset);
8245 if (filter->range) {
8247 ret = kstrtoul(args[1].from, 0, &filter->size);
8252 if (token == IF_SRC_FILE || token == IF_SRC_FILEADDR) {
8253 int fpos = filter->range ? 2 : 1;
8255 filename = match_strdup(&args[fpos]);
8262 state = IF_STATE_END;
8270 * Filter definition is fully parsed, validate and install it.
8271 * Make sure that it doesn't contradict itself or the event's
8274 if (state == IF_STATE_END) {
8276 if (kernel && event->attr.exclude_kernel)
8284 * For now, we only support file-based filters
8285 * in per-task events; doing so for CPU-wide
8286 * events requires additional context switching
8287 * trickery, since same object code will be
8288 * mapped at different virtual addresses in
8289 * different processes.
8292 if (!event->ctx->task)
8293 goto fail_free_name;
8295 /* look up the path and grab its inode */
8296 ret = kern_path(filename, LOOKUP_FOLLOW, &path);
8298 goto fail_free_name;
8300 filter->inode = igrab(d_inode(path.dentry));
8306 if (!filter->inode ||
8307 !S_ISREG(filter->inode->i_mode))
8308 /* free_filters_list() will iput() */
8311 event->addr_filters.nr_file_filters++;
8314 /* ready to consume more filters */
8315 state = IF_STATE_ACTION;
8320 if (state != IF_STATE_ACTION)
8330 free_filters_list(filters);
8337 perf_event_set_addr_filter(struct perf_event *event, char *filter_str)
8343 * Since this is called in perf_ioctl() path, we're already holding
8346 lockdep_assert_held(&event->ctx->mutex);
8348 if (WARN_ON_ONCE(event->parent))
8351 ret = perf_event_parse_addr_filter(event, filter_str, &filters);
8353 goto fail_clear_files;
8355 ret = event->pmu->addr_filters_validate(&filters);
8357 goto fail_free_filters;
8359 /* remove existing filters, if any */
8360 perf_addr_filters_splice(event, &filters);
8362 /* install new filters */
8363 perf_event_for_each_child(event, perf_event_addr_filters_apply);
8368 free_filters_list(&filters);
8371 event->addr_filters.nr_file_filters = 0;
8376 static int perf_event_set_filter(struct perf_event *event, void __user *arg)
8381 if ((event->attr.type != PERF_TYPE_TRACEPOINT ||
8382 !IS_ENABLED(CONFIG_EVENT_TRACING)) &&
8383 !has_addr_filter(event))
8386 filter_str = strndup_user(arg, PAGE_SIZE);
8387 if (IS_ERR(filter_str))
8388 return PTR_ERR(filter_str);
8390 if (IS_ENABLED(CONFIG_EVENT_TRACING) &&
8391 event->attr.type == PERF_TYPE_TRACEPOINT)
8392 ret = ftrace_profile_set_filter(event, event->attr.config,
8394 else if (has_addr_filter(event))
8395 ret = perf_event_set_addr_filter(event, filter_str);
8402 * hrtimer based swevent callback
8405 static enum hrtimer_restart perf_swevent_hrtimer(struct hrtimer *hrtimer)
8407 enum hrtimer_restart ret = HRTIMER_RESTART;
8408 struct perf_sample_data data;
8409 struct pt_regs *regs;
8410 struct perf_event *event;
8413 event = container_of(hrtimer, struct perf_event, hw.hrtimer);
8415 if (event->state != PERF_EVENT_STATE_ACTIVE)
8416 return HRTIMER_NORESTART;
8418 event->pmu->read(event);
8420 perf_sample_data_init(&data, 0, event->hw.last_period);
8421 regs = get_irq_regs();
8423 if (regs && !perf_exclude_event(event, regs)) {
8424 if (!(event->attr.exclude_idle && is_idle_task(current)))
8425 if (__perf_event_overflow(event, 1, &data, regs))
8426 ret = HRTIMER_NORESTART;
8429 period = max_t(u64, 10000, event->hw.sample_period);
8430 hrtimer_forward_now(hrtimer, ns_to_ktime(period));
8435 static void perf_swevent_start_hrtimer(struct perf_event *event)
8437 struct hw_perf_event *hwc = &event->hw;
8440 if (!is_sampling_event(event))
8443 period = local64_read(&hwc->period_left);
8448 local64_set(&hwc->period_left, 0);
8450 period = max_t(u64, 10000, hwc->sample_period);
8452 hrtimer_start(&hwc->hrtimer, ns_to_ktime(period),
8453 HRTIMER_MODE_REL_PINNED);
8456 static void perf_swevent_cancel_hrtimer(struct perf_event *event)
8458 struct hw_perf_event *hwc = &event->hw;
8460 if (is_sampling_event(event)) {
8461 ktime_t remaining = hrtimer_get_remaining(&hwc->hrtimer);
8462 local64_set(&hwc->period_left, ktime_to_ns(remaining));
8464 hrtimer_cancel(&hwc->hrtimer);
8468 static void perf_swevent_init_hrtimer(struct perf_event *event)
8470 struct hw_perf_event *hwc = &event->hw;
8472 if (!is_sampling_event(event))
8475 hrtimer_init(&hwc->hrtimer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
8476 hwc->hrtimer.function = perf_swevent_hrtimer;
8479 * Since hrtimers have a fixed rate, we can do a static freq->period
8480 * mapping and avoid the whole period adjust feedback stuff.
8482 if (event->attr.freq) {
8483 long freq = event->attr.sample_freq;
8485 event->attr.sample_period = NSEC_PER_SEC / freq;
8486 hwc->sample_period = event->attr.sample_period;
8487 local64_set(&hwc->period_left, hwc->sample_period);
8488 hwc->last_period = hwc->sample_period;
8489 event->attr.freq = 0;
8494 * Software event: cpu wall time clock
8497 static void cpu_clock_event_update(struct perf_event *event)
8502 now = local_clock();
8503 prev = local64_xchg(&event->hw.prev_count, now);
8504 local64_add(now - prev, &event->count);
8507 static void cpu_clock_event_start(struct perf_event *event, int flags)
8509 local64_set(&event->hw.prev_count, local_clock());
8510 perf_swevent_start_hrtimer(event);
8513 static void cpu_clock_event_stop(struct perf_event *event, int flags)
8515 perf_swevent_cancel_hrtimer(event);
8516 cpu_clock_event_update(event);
8519 static int cpu_clock_event_add(struct perf_event *event, int flags)
8521 if (flags & PERF_EF_START)
8522 cpu_clock_event_start(event, flags);
8523 perf_event_update_userpage(event);
8528 static void cpu_clock_event_del(struct perf_event *event, int flags)
8530 cpu_clock_event_stop(event, flags);
8533 static void cpu_clock_event_read(struct perf_event *event)
8535 cpu_clock_event_update(event);
8538 static int cpu_clock_event_init(struct perf_event *event)
8540 if (event->attr.type != PERF_TYPE_SOFTWARE)
8543 if (event->attr.config != PERF_COUNT_SW_CPU_CLOCK)
8547 * no branch sampling for software events
8549 if (has_branch_stack(event))
8552 perf_swevent_init_hrtimer(event);
8557 static struct pmu perf_cpu_clock = {
8558 .task_ctx_nr = perf_sw_context,
8560 .capabilities = PERF_PMU_CAP_NO_NMI,
8562 .event_init = cpu_clock_event_init,
8563 .add = cpu_clock_event_add,
8564 .del = cpu_clock_event_del,
8565 .start = cpu_clock_event_start,
8566 .stop = cpu_clock_event_stop,
8567 .read = cpu_clock_event_read,
8571 * Software event: task time clock
8574 static void task_clock_event_update(struct perf_event *event, u64 now)
8579 prev = local64_xchg(&event->hw.prev_count, now);
8581 local64_add(delta, &event->count);
8584 static void task_clock_event_start(struct perf_event *event, int flags)
8586 local64_set(&event->hw.prev_count, event->ctx->time);
8587 perf_swevent_start_hrtimer(event);
8590 static void task_clock_event_stop(struct perf_event *event, int flags)
8592 perf_swevent_cancel_hrtimer(event);
8593 task_clock_event_update(event, event->ctx->time);
8596 static int task_clock_event_add(struct perf_event *event, int flags)
8598 if (flags & PERF_EF_START)
8599 task_clock_event_start(event, flags);
8600 perf_event_update_userpage(event);
8605 static void task_clock_event_del(struct perf_event *event, int flags)
8607 task_clock_event_stop(event, PERF_EF_UPDATE);
8610 static void task_clock_event_read(struct perf_event *event)
8612 u64 now = perf_clock();
8613 u64 delta = now - event->ctx->timestamp;
8614 u64 time = event->ctx->time + delta;
8616 task_clock_event_update(event, time);
8619 static int task_clock_event_init(struct perf_event *event)
8621 if (event->attr.type != PERF_TYPE_SOFTWARE)
8624 if (event->attr.config != PERF_COUNT_SW_TASK_CLOCK)
8628 * no branch sampling for software events
8630 if (has_branch_stack(event))
8633 perf_swevent_init_hrtimer(event);
8638 static struct pmu perf_task_clock = {
8639 .task_ctx_nr = perf_sw_context,
8641 .capabilities = PERF_PMU_CAP_NO_NMI,
8643 .event_init = task_clock_event_init,
8644 .add = task_clock_event_add,
8645 .del = task_clock_event_del,
8646 .start = task_clock_event_start,
8647 .stop = task_clock_event_stop,
8648 .read = task_clock_event_read,
8651 static void perf_pmu_nop_void(struct pmu *pmu)
8655 static void perf_pmu_nop_txn(struct pmu *pmu, unsigned int flags)
8659 static int perf_pmu_nop_int(struct pmu *pmu)
8664 static DEFINE_PER_CPU(unsigned int, nop_txn_flags);
8666 static void perf_pmu_start_txn(struct pmu *pmu, unsigned int flags)
8668 __this_cpu_write(nop_txn_flags, flags);
8670 if (flags & ~PERF_PMU_TXN_ADD)
8673 perf_pmu_disable(pmu);
8676 static int perf_pmu_commit_txn(struct pmu *pmu)
8678 unsigned int flags = __this_cpu_read(nop_txn_flags);
8680 __this_cpu_write(nop_txn_flags, 0);
8682 if (flags & ~PERF_PMU_TXN_ADD)
8685 perf_pmu_enable(pmu);
8689 static void perf_pmu_cancel_txn(struct pmu *pmu)
8691 unsigned int flags = __this_cpu_read(nop_txn_flags);
8693 __this_cpu_write(nop_txn_flags, 0);
8695 if (flags & ~PERF_PMU_TXN_ADD)
8698 perf_pmu_enable(pmu);
8701 static int perf_event_idx_default(struct perf_event *event)
8707 * Ensures all contexts with the same task_ctx_nr have the same
8708 * pmu_cpu_context too.
8710 static struct perf_cpu_context __percpu *find_pmu_context(int ctxn)
8717 list_for_each_entry(pmu, &pmus, entry) {
8718 if (pmu->task_ctx_nr == ctxn)
8719 return pmu->pmu_cpu_context;
8725 static void free_pmu_context(struct pmu *pmu)
8727 mutex_lock(&pmus_lock);
8728 free_percpu(pmu->pmu_cpu_context);
8729 mutex_unlock(&pmus_lock);
8733 * Let userspace know that this PMU supports address range filtering:
8735 static ssize_t nr_addr_filters_show(struct device *dev,
8736 struct device_attribute *attr,
8739 struct pmu *pmu = dev_get_drvdata(dev);
8741 return snprintf(page, PAGE_SIZE - 1, "%d\n", pmu->nr_addr_filters);
8743 DEVICE_ATTR_RO(nr_addr_filters);
8745 static struct idr pmu_idr;
8748 type_show(struct device *dev, struct device_attribute *attr, char *page)
8750 struct pmu *pmu = dev_get_drvdata(dev);
8752 return snprintf(page, PAGE_SIZE-1, "%d\n", pmu->type);
8754 static DEVICE_ATTR_RO(type);
8757 perf_event_mux_interval_ms_show(struct device *dev,
8758 struct device_attribute *attr,
8761 struct pmu *pmu = dev_get_drvdata(dev);
8763 return snprintf(page, PAGE_SIZE-1, "%d\n", pmu->hrtimer_interval_ms);
8766 static DEFINE_MUTEX(mux_interval_mutex);
8769 perf_event_mux_interval_ms_store(struct device *dev,
8770 struct device_attribute *attr,
8771 const char *buf, size_t count)
8773 struct pmu *pmu = dev_get_drvdata(dev);
8774 int timer, cpu, ret;
8776 ret = kstrtoint(buf, 0, &timer);
8783 /* same value, noting to do */
8784 if (timer == pmu->hrtimer_interval_ms)
8787 mutex_lock(&mux_interval_mutex);
8788 pmu->hrtimer_interval_ms = timer;
8790 /* update all cpuctx for this PMU */
8792 for_each_online_cpu(cpu) {
8793 struct perf_cpu_context *cpuctx;
8794 cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
8795 cpuctx->hrtimer_interval = ns_to_ktime(NSEC_PER_MSEC * timer);
8797 cpu_function_call(cpu,
8798 (remote_function_f)perf_mux_hrtimer_restart, cpuctx);
8801 mutex_unlock(&mux_interval_mutex);
8805 static DEVICE_ATTR_RW(perf_event_mux_interval_ms);
8807 static struct attribute *pmu_dev_attrs[] = {
8808 &dev_attr_type.attr,
8809 &dev_attr_perf_event_mux_interval_ms.attr,
8812 ATTRIBUTE_GROUPS(pmu_dev);
8814 static int pmu_bus_running;
8815 static struct bus_type pmu_bus = {
8816 .name = "event_source",
8817 .dev_groups = pmu_dev_groups,
8820 static void pmu_dev_release(struct device *dev)
8825 static int pmu_dev_alloc(struct pmu *pmu)
8829 pmu->dev = kzalloc(sizeof(struct device), GFP_KERNEL);
8833 pmu->dev->groups = pmu->attr_groups;
8834 device_initialize(pmu->dev);
8835 ret = dev_set_name(pmu->dev, "%s", pmu->name);
8839 dev_set_drvdata(pmu->dev, pmu);
8840 pmu->dev->bus = &pmu_bus;
8841 pmu->dev->release = pmu_dev_release;
8842 ret = device_add(pmu->dev);
8846 /* For PMUs with address filters, throw in an extra attribute: */
8847 if (pmu->nr_addr_filters)
8848 ret = device_create_file(pmu->dev, &dev_attr_nr_addr_filters);
8857 device_del(pmu->dev);
8860 put_device(pmu->dev);
8864 static struct lock_class_key cpuctx_mutex;
8865 static struct lock_class_key cpuctx_lock;
8867 int perf_pmu_register(struct pmu *pmu, const char *name, int type)
8871 mutex_lock(&pmus_lock);
8873 pmu->pmu_disable_count = alloc_percpu(int);
8874 if (!pmu->pmu_disable_count)
8883 type = idr_alloc(&pmu_idr, pmu, PERF_TYPE_MAX, 0, GFP_KERNEL);
8891 if (pmu_bus_running) {
8892 ret = pmu_dev_alloc(pmu);
8898 if (pmu->task_ctx_nr == perf_hw_context) {
8899 static int hw_context_taken = 0;
8902 * Other than systems with heterogeneous CPUs, it never makes
8903 * sense for two PMUs to share perf_hw_context. PMUs which are
8904 * uncore must use perf_invalid_context.
8906 if (WARN_ON_ONCE(hw_context_taken &&
8907 !(pmu->capabilities & PERF_PMU_CAP_HETEROGENEOUS_CPUS)))
8908 pmu->task_ctx_nr = perf_invalid_context;
8910 hw_context_taken = 1;
8913 pmu->pmu_cpu_context = find_pmu_context(pmu->task_ctx_nr);
8914 if (pmu->pmu_cpu_context)
8915 goto got_cpu_context;
8918 pmu->pmu_cpu_context = alloc_percpu(struct perf_cpu_context);
8919 if (!pmu->pmu_cpu_context)
8922 for_each_possible_cpu(cpu) {
8923 struct perf_cpu_context *cpuctx;
8925 cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
8926 __perf_event_init_context(&cpuctx->ctx);
8927 lockdep_set_class(&cpuctx->ctx.mutex, &cpuctx_mutex);
8928 lockdep_set_class(&cpuctx->ctx.lock, &cpuctx_lock);
8929 cpuctx->ctx.pmu = pmu;
8931 __perf_mux_hrtimer_init(cpuctx, cpu);
8935 if (!pmu->start_txn) {
8936 if (pmu->pmu_enable) {
8938 * If we have pmu_enable/pmu_disable calls, install
8939 * transaction stubs that use that to try and batch
8940 * hardware accesses.
8942 pmu->start_txn = perf_pmu_start_txn;
8943 pmu->commit_txn = perf_pmu_commit_txn;
8944 pmu->cancel_txn = perf_pmu_cancel_txn;
8946 pmu->start_txn = perf_pmu_nop_txn;
8947 pmu->commit_txn = perf_pmu_nop_int;
8948 pmu->cancel_txn = perf_pmu_nop_void;
8952 if (!pmu->pmu_enable) {
8953 pmu->pmu_enable = perf_pmu_nop_void;
8954 pmu->pmu_disable = perf_pmu_nop_void;
8957 if (!pmu->event_idx)
8958 pmu->event_idx = perf_event_idx_default;
8960 list_add_rcu(&pmu->entry, &pmus);
8961 atomic_set(&pmu->exclusive_cnt, 0);
8964 mutex_unlock(&pmus_lock);
8969 device_del(pmu->dev);
8970 put_device(pmu->dev);
8973 if (pmu->type >= PERF_TYPE_MAX)
8974 idr_remove(&pmu_idr, pmu->type);
8977 free_percpu(pmu->pmu_disable_count);
8980 EXPORT_SYMBOL_GPL(perf_pmu_register);
8982 void perf_pmu_unregister(struct pmu *pmu)
8986 mutex_lock(&pmus_lock);
8987 remove_device = pmu_bus_running;
8988 list_del_rcu(&pmu->entry);
8989 mutex_unlock(&pmus_lock);
8992 * We dereference the pmu list under both SRCU and regular RCU, so
8993 * synchronize against both of those.
8995 synchronize_srcu(&pmus_srcu);
8998 free_percpu(pmu->pmu_disable_count);
8999 if (pmu->type >= PERF_TYPE_MAX)
9000 idr_remove(&pmu_idr, pmu->type);
9001 if (remove_device) {
9002 if (pmu->nr_addr_filters)
9003 device_remove_file(pmu->dev, &dev_attr_nr_addr_filters);
9004 device_del(pmu->dev);
9005 put_device(pmu->dev);
9007 free_pmu_context(pmu);
9009 EXPORT_SYMBOL_GPL(perf_pmu_unregister);
9011 static int perf_try_init_event(struct pmu *pmu, struct perf_event *event)
9013 struct perf_event_context *ctx = NULL;
9016 if (!try_module_get(pmu->module))
9019 if (event->group_leader != event) {
9021 * This ctx->mutex can nest when we're called through
9022 * inheritance. See the perf_event_ctx_lock_nested() comment.
9024 ctx = perf_event_ctx_lock_nested(event->group_leader,
9025 SINGLE_DEPTH_NESTING);
9030 ret = pmu->event_init(event);
9033 perf_event_ctx_unlock(event->group_leader, ctx);
9036 module_put(pmu->module);
9041 static struct pmu *perf_init_event(struct perf_event *event)
9043 struct pmu *pmu = NULL;
9047 idx = srcu_read_lock(&pmus_srcu);
9049 /* Try parent's PMU first: */
9050 if (event->parent && event->parent->pmu) {
9051 pmu = event->parent->pmu;
9052 ret = perf_try_init_event(pmu, event);
9058 pmu = idr_find(&pmu_idr, event->attr.type);
9061 ret = perf_try_init_event(pmu, event);
9067 list_for_each_entry_rcu(pmu, &pmus, entry) {
9068 ret = perf_try_init_event(pmu, event);
9072 if (ret != -ENOENT) {
9077 pmu = ERR_PTR(-ENOENT);
9079 srcu_read_unlock(&pmus_srcu, idx);
9084 static void attach_sb_event(struct perf_event *event)
9086 struct pmu_event_list *pel = per_cpu_ptr(&pmu_sb_events, event->cpu);
9088 raw_spin_lock(&pel->lock);
9089 list_add_rcu(&event->sb_list, &pel->list);
9090 raw_spin_unlock(&pel->lock);
9094 * We keep a list of all !task (and therefore per-cpu) events
9095 * that need to receive side-band records.
9097 * This avoids having to scan all the various PMU per-cpu contexts
9100 static void account_pmu_sb_event(struct perf_event *event)
9102 if (is_sb_event(event))
9103 attach_sb_event(event);
9106 static void account_event_cpu(struct perf_event *event, int cpu)
9111 if (is_cgroup_event(event))
9112 atomic_inc(&per_cpu(perf_cgroup_events, cpu));
9115 /* Freq events need the tick to stay alive (see perf_event_task_tick). */
9116 static void account_freq_event_nohz(void)
9118 #ifdef CONFIG_NO_HZ_FULL
9119 /* Lock so we don't race with concurrent unaccount */
9120 spin_lock(&nr_freq_lock);
9121 if (atomic_inc_return(&nr_freq_events) == 1)
9122 tick_nohz_dep_set(TICK_DEP_BIT_PERF_EVENTS);
9123 spin_unlock(&nr_freq_lock);
9127 static void account_freq_event(void)
9129 if (tick_nohz_full_enabled())
9130 account_freq_event_nohz();
9132 atomic_inc(&nr_freq_events);
9136 static void account_event(struct perf_event *event)
9143 if (event->attach_state & PERF_ATTACH_TASK)
9145 if (event->attr.mmap || event->attr.mmap_data)
9146 atomic_inc(&nr_mmap_events);
9147 if (event->attr.comm)
9148 atomic_inc(&nr_comm_events);
9149 if (event->attr.task)
9150 atomic_inc(&nr_task_events);
9151 if (event->attr.freq)
9152 account_freq_event();
9153 if (event->attr.context_switch) {
9154 atomic_inc(&nr_switch_events);
9157 if (has_branch_stack(event))
9159 if (is_cgroup_event(event))
9163 if (atomic_inc_not_zero(&perf_sched_count))
9166 mutex_lock(&perf_sched_mutex);
9167 if (!atomic_read(&perf_sched_count)) {
9168 static_branch_enable(&perf_sched_events);
9170 * Guarantee that all CPUs observe they key change and
9171 * call the perf scheduling hooks before proceeding to
9172 * install events that need them.
9174 synchronize_sched();
9177 * Now that we have waited for the sync_sched(), allow further
9178 * increments to by-pass the mutex.
9180 atomic_inc(&perf_sched_count);
9181 mutex_unlock(&perf_sched_mutex);
9185 account_event_cpu(event, event->cpu);
9187 account_pmu_sb_event(event);
9191 * Allocate and initialize a event structure
9193 static struct perf_event *
9194 perf_event_alloc(struct perf_event_attr *attr, int cpu,
9195 struct task_struct *task,
9196 struct perf_event *group_leader,
9197 struct perf_event *parent_event,
9198 perf_overflow_handler_t overflow_handler,
9199 void *context, int cgroup_fd)
9202 struct perf_event *event;
9203 struct hw_perf_event *hwc;
9206 if ((unsigned)cpu >= nr_cpu_ids) {
9207 if (!task || cpu != -1)
9208 return ERR_PTR(-EINVAL);
9211 event = kzalloc(sizeof(*event), GFP_KERNEL);
9213 return ERR_PTR(-ENOMEM);
9216 * Single events are their own group leaders, with an
9217 * empty sibling list:
9220 group_leader = event;
9222 mutex_init(&event->child_mutex);
9223 INIT_LIST_HEAD(&event->child_list);
9225 INIT_LIST_HEAD(&event->group_entry);
9226 INIT_LIST_HEAD(&event->event_entry);
9227 INIT_LIST_HEAD(&event->sibling_list);
9228 INIT_LIST_HEAD(&event->rb_entry);
9229 INIT_LIST_HEAD(&event->active_entry);
9230 INIT_LIST_HEAD(&event->addr_filters.list);
9231 INIT_HLIST_NODE(&event->hlist_entry);
9234 init_waitqueue_head(&event->waitq);
9235 init_irq_work(&event->pending, perf_pending_event);
9237 mutex_init(&event->mmap_mutex);
9238 raw_spin_lock_init(&event->addr_filters.lock);
9240 atomic_long_set(&event->refcount, 1);
9242 event->attr = *attr;
9243 event->group_leader = group_leader;
9247 event->parent = parent_event;
9249 event->ns = get_pid_ns(task_active_pid_ns(current));
9250 event->id = atomic64_inc_return(&perf_event_id);
9252 event->state = PERF_EVENT_STATE_INACTIVE;
9255 event->attach_state = PERF_ATTACH_TASK;
9257 * XXX pmu::event_init needs to know what task to account to
9258 * and we cannot use the ctx information because we need the
9259 * pmu before we get a ctx.
9261 event->hw.target = task;
9264 event->clock = &local_clock;
9266 event->clock = parent_event->clock;
9268 if (!overflow_handler && parent_event) {
9269 overflow_handler = parent_event->overflow_handler;
9270 context = parent_event->overflow_handler_context;
9271 #if defined(CONFIG_BPF_SYSCALL) && defined(CONFIG_EVENT_TRACING)
9272 if (overflow_handler == bpf_overflow_handler) {
9273 struct bpf_prog *prog = bpf_prog_inc(parent_event->prog);
9276 err = PTR_ERR(prog);
9280 event->orig_overflow_handler =
9281 parent_event->orig_overflow_handler;
9286 if (overflow_handler) {
9287 event->overflow_handler = overflow_handler;
9288 event->overflow_handler_context = context;
9289 } else if (is_write_backward(event)){
9290 event->overflow_handler = perf_event_output_backward;
9291 event->overflow_handler_context = NULL;
9293 event->overflow_handler = perf_event_output_forward;
9294 event->overflow_handler_context = NULL;
9297 perf_event__state_init(event);
9302 hwc->sample_period = attr->sample_period;
9303 if (attr->freq && attr->sample_freq)
9304 hwc->sample_period = 1;
9305 hwc->last_period = hwc->sample_period;
9307 local64_set(&hwc->period_left, hwc->sample_period);
9310 * we currently do not support PERF_FORMAT_GROUP on inherited events
9312 if (attr->inherit && (attr->read_format & PERF_FORMAT_GROUP))
9315 if (!has_branch_stack(event))
9316 event->attr.branch_sample_type = 0;
9318 if (cgroup_fd != -1) {
9319 err = perf_cgroup_connect(cgroup_fd, event, attr, group_leader);
9324 pmu = perf_init_event(event);
9327 else if (IS_ERR(pmu)) {
9332 err = exclusive_event_init(event);
9336 if (has_addr_filter(event)) {
9337 event->addr_filters_offs = kcalloc(pmu->nr_addr_filters,
9338 sizeof(unsigned long),
9340 if (!event->addr_filters_offs)
9343 /* force hw sync on the address filters */
9344 event->addr_filters_gen = 1;
9347 if (!event->parent) {
9348 if (event->attr.sample_type & PERF_SAMPLE_CALLCHAIN) {
9349 err = get_callchain_buffers(attr->sample_max_stack);
9351 goto err_addr_filters;
9355 /* symmetric to unaccount_event() in _free_event() */
9356 account_event(event);
9361 kfree(event->addr_filters_offs);
9364 exclusive_event_destroy(event);
9368 event->destroy(event);
9369 module_put(pmu->module);
9371 if (is_cgroup_event(event))
9372 perf_detach_cgroup(event);
9374 put_pid_ns(event->ns);
9377 return ERR_PTR(err);
9380 static int perf_copy_attr(struct perf_event_attr __user *uattr,
9381 struct perf_event_attr *attr)
9386 if (!access_ok(VERIFY_WRITE, uattr, PERF_ATTR_SIZE_VER0))
9390 * zero the full structure, so that a short copy will be nice.
9392 memset(attr, 0, sizeof(*attr));
9394 ret = get_user(size, &uattr->size);
9398 if (size > PAGE_SIZE) /* silly large */
9401 if (!size) /* abi compat */
9402 size = PERF_ATTR_SIZE_VER0;
9404 if (size < PERF_ATTR_SIZE_VER0)
9408 * If we're handed a bigger struct than we know of,
9409 * ensure all the unknown bits are 0 - i.e. new
9410 * user-space does not rely on any kernel feature
9411 * extensions we dont know about yet.
9413 if (size > sizeof(*attr)) {
9414 unsigned char __user *addr;
9415 unsigned char __user *end;
9418 addr = (void __user *)uattr + sizeof(*attr);
9419 end = (void __user *)uattr + size;
9421 for (; addr < end; addr++) {
9422 ret = get_user(val, addr);
9428 size = sizeof(*attr);
9431 ret = copy_from_user(attr, uattr, size);
9435 if (attr->__reserved_1)
9438 if (attr->sample_type & ~(PERF_SAMPLE_MAX-1))
9441 if (attr->read_format & ~(PERF_FORMAT_MAX-1))
9444 if (attr->sample_type & PERF_SAMPLE_BRANCH_STACK) {
9445 u64 mask = attr->branch_sample_type;
9447 /* only using defined bits */
9448 if (mask & ~(PERF_SAMPLE_BRANCH_MAX-1))
9451 /* at least one branch bit must be set */
9452 if (!(mask & ~PERF_SAMPLE_BRANCH_PLM_ALL))
9455 /* propagate priv level, when not set for branch */
9456 if (!(mask & PERF_SAMPLE_BRANCH_PLM_ALL)) {
9458 /* exclude_kernel checked on syscall entry */
9459 if (!attr->exclude_kernel)
9460 mask |= PERF_SAMPLE_BRANCH_KERNEL;
9462 if (!attr->exclude_user)
9463 mask |= PERF_SAMPLE_BRANCH_USER;
9465 if (!attr->exclude_hv)
9466 mask |= PERF_SAMPLE_BRANCH_HV;
9468 * adjust user setting (for HW filter setup)
9470 attr->branch_sample_type = mask;
9472 /* privileged levels capture (kernel, hv): check permissions */
9473 if ((mask & PERF_SAMPLE_BRANCH_PERM_PLM)
9474 && perf_paranoid_kernel() && !capable(CAP_SYS_ADMIN))
9478 if (attr->sample_type & PERF_SAMPLE_REGS_USER) {
9479 ret = perf_reg_validate(attr->sample_regs_user);
9484 if (attr->sample_type & PERF_SAMPLE_STACK_USER) {
9485 if (!arch_perf_have_user_stack_dump())
9489 * We have __u32 type for the size, but so far
9490 * we can only use __u16 as maximum due to the
9491 * __u16 sample size limit.
9493 if (attr->sample_stack_user >= USHRT_MAX)
9495 else if (!IS_ALIGNED(attr->sample_stack_user, sizeof(u64)))
9499 if (attr->sample_type & PERF_SAMPLE_REGS_INTR)
9500 ret = perf_reg_validate(attr->sample_regs_intr);
9505 put_user(sizeof(*attr), &uattr->size);
9511 perf_event_set_output(struct perf_event *event, struct perf_event *output_event)
9513 struct ring_buffer *rb = NULL;
9519 /* don't allow circular references */
9520 if (event == output_event)
9524 * Don't allow cross-cpu buffers
9526 if (output_event->cpu != event->cpu)
9530 * If its not a per-cpu rb, it must be the same task.
9532 if (output_event->cpu == -1 && output_event->ctx != event->ctx)
9536 * Mixing clocks in the same buffer is trouble you don't need.
9538 if (output_event->clock != event->clock)
9542 * Either writing ring buffer from beginning or from end.
9543 * Mixing is not allowed.
9545 if (is_write_backward(output_event) != is_write_backward(event))
9549 * If both events generate aux data, they must be on the same PMU
9551 if (has_aux(event) && has_aux(output_event) &&
9552 event->pmu != output_event->pmu)
9556 mutex_lock(&event->mmap_mutex);
9557 /* Can't redirect output if we've got an active mmap() */
9558 if (atomic_read(&event->mmap_count))
9562 /* get the rb we want to redirect to */
9563 rb = ring_buffer_get(output_event);
9568 ring_buffer_attach(event, rb);
9572 mutex_unlock(&event->mmap_mutex);
9578 static void mutex_lock_double(struct mutex *a, struct mutex *b)
9584 mutex_lock_nested(b, SINGLE_DEPTH_NESTING);
9587 static int perf_event_set_clock(struct perf_event *event, clockid_t clk_id)
9589 bool nmi_safe = false;
9592 case CLOCK_MONOTONIC:
9593 event->clock = &ktime_get_mono_fast_ns;
9597 case CLOCK_MONOTONIC_RAW:
9598 event->clock = &ktime_get_raw_fast_ns;
9602 case CLOCK_REALTIME:
9603 event->clock = &ktime_get_real_ns;
9606 case CLOCK_BOOTTIME:
9607 event->clock = &ktime_get_boot_ns;
9611 event->clock = &ktime_get_tai_ns;
9618 if (!nmi_safe && !(event->pmu->capabilities & PERF_PMU_CAP_NO_NMI))
9625 * Variation on perf_event_ctx_lock_nested(), except we take two context
9628 static struct perf_event_context *
9629 __perf_event_ctx_lock_double(struct perf_event *group_leader,
9630 struct perf_event_context *ctx)
9632 struct perf_event_context *gctx;
9636 gctx = READ_ONCE(group_leader->ctx);
9637 if (!atomic_inc_not_zero(&gctx->refcount)) {
9643 mutex_lock_double(&gctx->mutex, &ctx->mutex);
9645 if (group_leader->ctx != gctx) {
9646 mutex_unlock(&ctx->mutex);
9647 mutex_unlock(&gctx->mutex);
9656 * sys_perf_event_open - open a performance event, associate it to a task/cpu
9658 * @attr_uptr: event_id type attributes for monitoring/sampling
9661 * @group_fd: group leader event fd
9663 SYSCALL_DEFINE5(perf_event_open,
9664 struct perf_event_attr __user *, attr_uptr,
9665 pid_t, pid, int, cpu, int, group_fd, unsigned long, flags)
9667 struct perf_event *group_leader = NULL, *output_event = NULL;
9668 struct perf_event *event, *sibling;
9669 struct perf_event_attr attr;
9670 struct perf_event_context *ctx, *uninitialized_var(gctx);
9671 struct file *event_file = NULL;
9672 struct fd group = {NULL, 0};
9673 struct task_struct *task = NULL;
9678 int f_flags = O_RDWR;
9681 /* for future expandability... */
9682 if (flags & ~PERF_FLAG_ALL)
9685 err = perf_copy_attr(attr_uptr, &attr);
9689 if (!attr.exclude_kernel) {
9690 if (perf_paranoid_kernel() && !capable(CAP_SYS_ADMIN))
9695 if (attr.sample_freq > sysctl_perf_event_sample_rate)
9698 if (attr.sample_period & (1ULL << 63))
9702 if (!attr.sample_max_stack)
9703 attr.sample_max_stack = sysctl_perf_event_max_stack;
9706 * In cgroup mode, the pid argument is used to pass the fd
9707 * opened to the cgroup directory in cgroupfs. The cpu argument
9708 * designates the cpu on which to monitor threads from that
9711 if ((flags & PERF_FLAG_PID_CGROUP) && (pid == -1 || cpu == -1))
9714 if (flags & PERF_FLAG_FD_CLOEXEC)
9715 f_flags |= O_CLOEXEC;
9717 event_fd = get_unused_fd_flags(f_flags);
9721 if (group_fd != -1) {
9722 err = perf_fget_light(group_fd, &group);
9725 group_leader = group.file->private_data;
9726 if (flags & PERF_FLAG_FD_OUTPUT)
9727 output_event = group_leader;
9728 if (flags & PERF_FLAG_FD_NO_GROUP)
9729 group_leader = NULL;
9732 if (pid != -1 && !(flags & PERF_FLAG_PID_CGROUP)) {
9733 task = find_lively_task_by_vpid(pid);
9735 err = PTR_ERR(task);
9740 if (task && group_leader &&
9741 group_leader->attr.inherit != attr.inherit) {
9749 err = mutex_lock_interruptible(&task->signal->cred_guard_mutex);
9754 * Reuse ptrace permission checks for now.
9756 * We must hold cred_guard_mutex across this and any potential
9757 * perf_install_in_context() call for this new event to
9758 * serialize against exec() altering our credentials (and the
9759 * perf_event_exit_task() that could imply).
9762 if (!ptrace_may_access(task, PTRACE_MODE_READ_REALCREDS))
9766 if (flags & PERF_FLAG_PID_CGROUP)
9769 event = perf_event_alloc(&attr, cpu, task, group_leader, NULL,
9770 NULL, NULL, cgroup_fd);
9771 if (IS_ERR(event)) {
9772 err = PTR_ERR(event);
9776 if (is_sampling_event(event)) {
9777 if (event->pmu->capabilities & PERF_PMU_CAP_NO_INTERRUPT) {
9784 * Special case software events and allow them to be part of
9785 * any hardware group.
9789 if (attr.use_clockid) {
9790 err = perf_event_set_clock(event, attr.clockid);
9795 if (pmu->task_ctx_nr == perf_sw_context)
9796 event->event_caps |= PERF_EV_CAP_SOFTWARE;
9799 (is_software_event(event) != is_software_event(group_leader))) {
9800 if (is_software_event(event)) {
9802 * If event and group_leader are not both a software
9803 * event, and event is, then group leader is not.
9805 * Allow the addition of software events to !software
9806 * groups, this is safe because software events never
9809 pmu = group_leader->pmu;
9810 } else if (is_software_event(group_leader) &&
9811 (group_leader->group_caps & PERF_EV_CAP_SOFTWARE)) {
9813 * In case the group is a pure software group, and we
9814 * try to add a hardware event, move the whole group to
9815 * the hardware context.
9822 * Get the target context (task or percpu):
9824 ctx = find_get_context(pmu, task, event);
9830 if ((pmu->capabilities & PERF_PMU_CAP_EXCLUSIVE) && group_leader) {
9836 * Look up the group leader (we will attach this event to it):
9842 * Do not allow a recursive hierarchy (this new sibling
9843 * becoming part of another group-sibling):
9845 if (group_leader->group_leader != group_leader)
9848 /* All events in a group should have the same clock */
9849 if (group_leader->clock != event->clock)
9853 * Do not allow to attach to a group in a different
9854 * task or CPU context:
9858 * Make sure we're both on the same task, or both
9861 if (group_leader->ctx->task != ctx->task)
9865 * Make sure we're both events for the same CPU;
9866 * grouping events for different CPUs is broken; since
9867 * you can never concurrently schedule them anyhow.
9869 if (group_leader->cpu != event->cpu)
9872 if (group_leader->ctx != ctx)
9877 * Only a group leader can be exclusive or pinned
9879 if (attr.exclusive || attr.pinned)
9884 err = perf_event_set_output(event, output_event);
9889 event_file = anon_inode_getfile("[perf_event]", &perf_fops, event,
9891 if (IS_ERR(event_file)) {
9892 err = PTR_ERR(event_file);
9898 gctx = __perf_event_ctx_lock_double(group_leader, ctx);
9900 if (gctx->task == TASK_TOMBSTONE) {
9906 * Check if we raced against another sys_perf_event_open() call
9907 * moving the software group underneath us.
9909 if (!(group_leader->group_caps & PERF_EV_CAP_SOFTWARE)) {
9911 * If someone moved the group out from under us, check
9912 * if this new event wound up on the same ctx, if so
9913 * its the regular !move_group case, otherwise fail.
9919 perf_event_ctx_unlock(group_leader, gctx);
9924 mutex_lock(&ctx->mutex);
9927 if (ctx->task == TASK_TOMBSTONE) {
9932 if (!perf_event_validate_size(event)) {
9938 * Must be under the same ctx::mutex as perf_install_in_context(),
9939 * because we need to serialize with concurrent event creation.
9941 if (!exclusive_event_installable(event, ctx)) {
9942 /* exclusive and group stuff are assumed mutually exclusive */
9943 WARN_ON_ONCE(move_group);
9949 WARN_ON_ONCE(ctx->parent_ctx);
9952 * This is the point on no return; we cannot fail hereafter. This is
9953 * where we start modifying current state.
9958 * See perf_event_ctx_lock() for comments on the details
9959 * of swizzling perf_event::ctx.
9961 perf_remove_from_context(group_leader, 0);
9964 list_for_each_entry(sibling, &group_leader->sibling_list,
9966 perf_remove_from_context(sibling, 0);
9971 * Wait for everybody to stop referencing the events through
9972 * the old lists, before installing it on new lists.
9977 * Install the group siblings before the group leader.
9979 * Because a group leader will try and install the entire group
9980 * (through the sibling list, which is still in-tact), we can
9981 * end up with siblings installed in the wrong context.
9983 * By installing siblings first we NO-OP because they're not
9984 * reachable through the group lists.
9986 list_for_each_entry(sibling, &group_leader->sibling_list,
9988 perf_event__state_init(sibling);
9989 perf_install_in_context(ctx, sibling, sibling->cpu);
9994 * Removing from the context ends up with disabled
9995 * event. What we want here is event in the initial
9996 * startup state, ready to be add into new context.
9998 perf_event__state_init(group_leader);
9999 perf_install_in_context(ctx, group_leader, group_leader->cpu);
10004 * Precalculate sample_data sizes; do while holding ctx::mutex such
10005 * that we're serialized against further additions and before
10006 * perf_install_in_context() which is the point the event is active and
10007 * can use these values.
10009 perf_event__header_size(event);
10010 perf_event__id_header_size(event);
10012 event->owner = current;
10014 perf_install_in_context(ctx, event, event->cpu);
10015 perf_unpin_context(ctx);
10018 perf_event_ctx_unlock(group_leader, gctx);
10019 mutex_unlock(&ctx->mutex);
10022 mutex_unlock(&task->signal->cred_guard_mutex);
10023 put_task_struct(task);
10028 mutex_lock(¤t->perf_event_mutex);
10029 list_add_tail(&event->owner_entry, ¤t->perf_event_list);
10030 mutex_unlock(¤t->perf_event_mutex);
10033 * Drop the reference on the group_event after placing the
10034 * new event on the sibling_list. This ensures destruction
10035 * of the group leader will find the pointer to itself in
10036 * perf_group_detach().
10039 fd_install(event_fd, event_file);
10044 perf_event_ctx_unlock(group_leader, gctx);
10045 mutex_unlock(&ctx->mutex);
10049 perf_unpin_context(ctx);
10053 * If event_file is set, the fput() above will have called ->release()
10054 * and that will take care of freeing the event.
10060 mutex_unlock(&task->signal->cred_guard_mutex);
10065 put_task_struct(task);
10069 put_unused_fd(event_fd);
10074 * perf_event_create_kernel_counter
10076 * @attr: attributes of the counter to create
10077 * @cpu: cpu in which the counter is bound
10078 * @task: task to profile (NULL for percpu)
10080 struct perf_event *
10081 perf_event_create_kernel_counter(struct perf_event_attr *attr, int cpu,
10082 struct task_struct *task,
10083 perf_overflow_handler_t overflow_handler,
10086 struct perf_event_context *ctx;
10087 struct perf_event *event;
10091 * Get the target context (task or percpu):
10094 event = perf_event_alloc(attr, cpu, task, NULL, NULL,
10095 overflow_handler, context, -1);
10096 if (IS_ERR(event)) {
10097 err = PTR_ERR(event);
10101 /* Mark owner so we could distinguish it from user events. */
10102 event->owner = TASK_TOMBSTONE;
10104 ctx = find_get_context(event->pmu, task, event);
10106 err = PTR_ERR(ctx);
10110 WARN_ON_ONCE(ctx->parent_ctx);
10111 mutex_lock(&ctx->mutex);
10112 if (ctx->task == TASK_TOMBSTONE) {
10117 if (!exclusive_event_installable(event, ctx)) {
10122 perf_install_in_context(ctx, event, cpu);
10123 perf_unpin_context(ctx);
10124 mutex_unlock(&ctx->mutex);
10129 mutex_unlock(&ctx->mutex);
10130 perf_unpin_context(ctx);
10135 return ERR_PTR(err);
10137 EXPORT_SYMBOL_GPL(perf_event_create_kernel_counter);
10139 void perf_pmu_migrate_context(struct pmu *pmu, int src_cpu, int dst_cpu)
10141 struct perf_event_context *src_ctx;
10142 struct perf_event_context *dst_ctx;
10143 struct perf_event *event, *tmp;
10146 src_ctx = &per_cpu_ptr(pmu->pmu_cpu_context, src_cpu)->ctx;
10147 dst_ctx = &per_cpu_ptr(pmu->pmu_cpu_context, dst_cpu)->ctx;
10150 * See perf_event_ctx_lock() for comments on the details
10151 * of swizzling perf_event::ctx.
10153 mutex_lock_double(&src_ctx->mutex, &dst_ctx->mutex);
10154 list_for_each_entry_safe(event, tmp, &src_ctx->event_list,
10156 perf_remove_from_context(event, 0);
10157 unaccount_event_cpu(event, src_cpu);
10159 list_add(&event->migrate_entry, &events);
10163 * Wait for the events to quiesce before re-instating them.
10168 * Re-instate events in 2 passes.
10170 * Skip over group leaders and only install siblings on this first
10171 * pass, siblings will not get enabled without a leader, however a
10172 * leader will enable its siblings, even if those are still on the old
10175 list_for_each_entry_safe(event, tmp, &events, migrate_entry) {
10176 if (event->group_leader == event)
10179 list_del(&event->migrate_entry);
10180 if (event->state >= PERF_EVENT_STATE_OFF)
10181 event->state = PERF_EVENT_STATE_INACTIVE;
10182 account_event_cpu(event, dst_cpu);
10183 perf_install_in_context(dst_ctx, event, dst_cpu);
10188 * Once all the siblings are setup properly, install the group leaders
10191 list_for_each_entry_safe(event, tmp, &events, migrate_entry) {
10192 list_del(&event->migrate_entry);
10193 if (event->state >= PERF_EVENT_STATE_OFF)
10194 event->state = PERF_EVENT_STATE_INACTIVE;
10195 account_event_cpu(event, dst_cpu);
10196 perf_install_in_context(dst_ctx, event, dst_cpu);
10199 mutex_unlock(&dst_ctx->mutex);
10200 mutex_unlock(&src_ctx->mutex);
10202 EXPORT_SYMBOL_GPL(perf_pmu_migrate_context);
10204 static void sync_child_event(struct perf_event *child_event,
10205 struct task_struct *child)
10207 struct perf_event *parent_event = child_event->parent;
10210 if (child_event->attr.inherit_stat)
10211 perf_event_read_event(child_event, child);
10213 child_val = perf_event_count(child_event);
10216 * Add back the child's count to the parent's count:
10218 atomic64_add(child_val, &parent_event->child_count);
10219 atomic64_add(child_event->total_time_enabled,
10220 &parent_event->child_total_time_enabled);
10221 atomic64_add(child_event->total_time_running,
10222 &parent_event->child_total_time_running);
10226 perf_event_exit_event(struct perf_event *child_event,
10227 struct perf_event_context *child_ctx,
10228 struct task_struct *child)
10230 struct perf_event *parent_event = child_event->parent;
10233 * Do not destroy the 'original' grouping; because of the context
10234 * switch optimization the original events could've ended up in a
10235 * random child task.
10237 * If we were to destroy the original group, all group related
10238 * operations would cease to function properly after this random
10241 * Do destroy all inherited groups, we don't care about those
10242 * and being thorough is better.
10244 raw_spin_lock_irq(&child_ctx->lock);
10245 WARN_ON_ONCE(child_ctx->is_active);
10248 perf_group_detach(child_event);
10249 list_del_event(child_event, child_ctx);
10250 child_event->state = PERF_EVENT_STATE_EXIT; /* is_event_hup() */
10251 raw_spin_unlock_irq(&child_ctx->lock);
10254 * Parent events are governed by their filedesc, retain them.
10256 if (!parent_event) {
10257 perf_event_wakeup(child_event);
10261 * Child events can be cleaned up.
10264 sync_child_event(child_event, child);
10267 * Remove this event from the parent's list
10269 WARN_ON_ONCE(parent_event->ctx->parent_ctx);
10270 mutex_lock(&parent_event->child_mutex);
10271 list_del_init(&child_event->child_list);
10272 mutex_unlock(&parent_event->child_mutex);
10275 * Kick perf_poll() for is_event_hup().
10277 perf_event_wakeup(parent_event);
10278 free_event(child_event);
10279 put_event(parent_event);
10282 static void perf_event_exit_task_context(struct task_struct *child, int ctxn)
10284 struct perf_event_context *child_ctx, *clone_ctx = NULL;
10285 struct perf_event *child_event, *next;
10287 WARN_ON_ONCE(child != current);
10289 child_ctx = perf_pin_task_context(child, ctxn);
10294 * In order to reduce the amount of tricky in ctx tear-down, we hold
10295 * ctx::mutex over the entire thing. This serializes against almost
10296 * everything that wants to access the ctx.
10298 * The exception is sys_perf_event_open() /
10299 * perf_event_create_kernel_count() which does find_get_context()
10300 * without ctx::mutex (it cannot because of the move_group double mutex
10301 * lock thing). See the comments in perf_install_in_context().
10303 mutex_lock(&child_ctx->mutex);
10306 * In a single ctx::lock section, de-schedule the events and detach the
10307 * context from the task such that we cannot ever get it scheduled back
10310 raw_spin_lock_irq(&child_ctx->lock);
10311 task_ctx_sched_out(__get_cpu_context(child_ctx), child_ctx, EVENT_ALL);
10314 * Now that the context is inactive, destroy the task <-> ctx relation
10315 * and mark the context dead.
10317 RCU_INIT_POINTER(child->perf_event_ctxp[ctxn], NULL);
10318 put_ctx(child_ctx); /* cannot be last */
10319 WRITE_ONCE(child_ctx->task, TASK_TOMBSTONE);
10320 put_task_struct(current); /* cannot be last */
10322 clone_ctx = unclone_ctx(child_ctx);
10323 raw_spin_unlock_irq(&child_ctx->lock);
10326 put_ctx(clone_ctx);
10329 * Report the task dead after unscheduling the events so that we
10330 * won't get any samples after PERF_RECORD_EXIT. We can however still
10331 * get a few PERF_RECORD_READ events.
10333 perf_event_task(child, child_ctx, 0);
10335 list_for_each_entry_safe(child_event, next, &child_ctx->event_list, event_entry)
10336 perf_event_exit_event(child_event, child_ctx, child);
10338 mutex_unlock(&child_ctx->mutex);
10340 put_ctx(child_ctx);
10344 * When a child task exits, feed back event values to parent events.
10346 * Can be called with cred_guard_mutex held when called from
10347 * install_exec_creds().
10349 void perf_event_exit_task(struct task_struct *child)
10351 struct perf_event *event, *tmp;
10354 mutex_lock(&child->perf_event_mutex);
10355 list_for_each_entry_safe(event, tmp, &child->perf_event_list,
10357 list_del_init(&event->owner_entry);
10360 * Ensure the list deletion is visible before we clear
10361 * the owner, closes a race against perf_release() where
10362 * we need to serialize on the owner->perf_event_mutex.
10364 smp_store_release(&event->owner, NULL);
10366 mutex_unlock(&child->perf_event_mutex);
10368 for_each_task_context_nr(ctxn)
10369 perf_event_exit_task_context(child, ctxn);
10372 * The perf_event_exit_task_context calls perf_event_task
10373 * with child's task_ctx, which generates EXIT events for
10374 * child contexts and sets child->perf_event_ctxp[] to NULL.
10375 * At this point we need to send EXIT events to cpu contexts.
10377 perf_event_task(child, NULL, 0);
10380 static void perf_free_event(struct perf_event *event,
10381 struct perf_event_context *ctx)
10383 struct perf_event *parent = event->parent;
10385 if (WARN_ON_ONCE(!parent))
10388 mutex_lock(&parent->child_mutex);
10389 list_del_init(&event->child_list);
10390 mutex_unlock(&parent->child_mutex);
10394 raw_spin_lock_irq(&ctx->lock);
10395 perf_group_detach(event);
10396 list_del_event(event, ctx);
10397 raw_spin_unlock_irq(&ctx->lock);
10402 * Free an unexposed, unused context as created by inheritance by
10403 * perf_event_init_task below, used by fork() in case of fail.
10405 * Not all locks are strictly required, but take them anyway to be nice and
10406 * help out with the lockdep assertions.
10408 void perf_event_free_task(struct task_struct *task)
10410 struct perf_event_context *ctx;
10411 struct perf_event *event, *tmp;
10414 for_each_task_context_nr(ctxn) {
10415 ctx = task->perf_event_ctxp[ctxn];
10419 mutex_lock(&ctx->mutex);
10421 list_for_each_entry_safe(event, tmp, &ctx->pinned_groups,
10423 perf_free_event(event, ctx);
10425 list_for_each_entry_safe(event, tmp, &ctx->flexible_groups,
10427 perf_free_event(event, ctx);
10429 if (!list_empty(&ctx->pinned_groups) ||
10430 !list_empty(&ctx->flexible_groups))
10433 mutex_unlock(&ctx->mutex);
10439 void perf_event_delayed_put(struct task_struct *task)
10443 for_each_task_context_nr(ctxn)
10444 WARN_ON_ONCE(task->perf_event_ctxp[ctxn]);
10447 struct file *perf_event_get(unsigned int fd)
10451 file = fget_raw(fd);
10453 return ERR_PTR(-EBADF);
10455 if (file->f_op != &perf_fops) {
10457 return ERR_PTR(-EBADF);
10463 const struct perf_event_attr *perf_event_attrs(struct perf_event *event)
10466 return ERR_PTR(-EINVAL);
10468 return &event->attr;
10472 * inherit a event from parent task to child task:
10474 static struct perf_event *
10475 inherit_event(struct perf_event *parent_event,
10476 struct task_struct *parent,
10477 struct perf_event_context *parent_ctx,
10478 struct task_struct *child,
10479 struct perf_event *group_leader,
10480 struct perf_event_context *child_ctx)
10482 enum perf_event_active_state parent_state = parent_event->state;
10483 struct perf_event *child_event;
10484 unsigned long flags;
10487 * Instead of creating recursive hierarchies of events,
10488 * we link inherited events back to the original parent,
10489 * which has a filp for sure, which we use as the reference
10492 if (parent_event->parent)
10493 parent_event = parent_event->parent;
10495 child_event = perf_event_alloc(&parent_event->attr,
10498 group_leader, parent_event,
10500 if (IS_ERR(child_event))
10501 return child_event;
10504 * is_orphaned_event() and list_add_tail(&parent_event->child_list)
10505 * must be under the same lock in order to serialize against
10506 * perf_event_release_kernel(), such that either we must observe
10507 * is_orphaned_event() or they will observe us on the child_list.
10509 mutex_lock(&parent_event->child_mutex);
10510 if (is_orphaned_event(parent_event) ||
10511 !atomic_long_inc_not_zero(&parent_event->refcount)) {
10512 mutex_unlock(&parent_event->child_mutex);
10513 free_event(child_event);
10517 get_ctx(child_ctx);
10520 * Make the child state follow the state of the parent event,
10521 * not its attr.disabled bit. We hold the parent's mutex,
10522 * so we won't race with perf_event_{en, dis}able_family.
10524 if (parent_state >= PERF_EVENT_STATE_INACTIVE)
10525 child_event->state = PERF_EVENT_STATE_INACTIVE;
10527 child_event->state = PERF_EVENT_STATE_OFF;
10529 if (parent_event->attr.freq) {
10530 u64 sample_period = parent_event->hw.sample_period;
10531 struct hw_perf_event *hwc = &child_event->hw;
10533 hwc->sample_period = sample_period;
10534 hwc->last_period = sample_period;
10536 local64_set(&hwc->period_left, sample_period);
10539 child_event->ctx = child_ctx;
10540 child_event->overflow_handler = parent_event->overflow_handler;
10541 child_event->overflow_handler_context
10542 = parent_event->overflow_handler_context;
10545 * Precalculate sample_data sizes
10547 perf_event__header_size(child_event);
10548 perf_event__id_header_size(child_event);
10551 * Link it up in the child's context:
10553 raw_spin_lock_irqsave(&child_ctx->lock, flags);
10554 add_event_to_ctx(child_event, child_ctx);
10555 raw_spin_unlock_irqrestore(&child_ctx->lock, flags);
10558 * Link this into the parent event's child list
10560 list_add_tail(&child_event->child_list, &parent_event->child_list);
10561 mutex_unlock(&parent_event->child_mutex);
10563 return child_event;
10566 static int inherit_group(struct perf_event *parent_event,
10567 struct task_struct *parent,
10568 struct perf_event_context *parent_ctx,
10569 struct task_struct *child,
10570 struct perf_event_context *child_ctx)
10572 struct perf_event *leader;
10573 struct perf_event *sub;
10574 struct perf_event *child_ctr;
10576 leader = inherit_event(parent_event, parent, parent_ctx,
10577 child, NULL, child_ctx);
10578 if (IS_ERR(leader))
10579 return PTR_ERR(leader);
10580 list_for_each_entry(sub, &parent_event->sibling_list, group_entry) {
10581 child_ctr = inherit_event(sub, parent, parent_ctx,
10582 child, leader, child_ctx);
10583 if (IS_ERR(child_ctr))
10584 return PTR_ERR(child_ctr);
10590 inherit_task_group(struct perf_event *event, struct task_struct *parent,
10591 struct perf_event_context *parent_ctx,
10592 struct task_struct *child, int ctxn,
10593 int *inherited_all)
10596 struct perf_event_context *child_ctx;
10598 if (!event->attr.inherit) {
10599 *inherited_all = 0;
10603 child_ctx = child->perf_event_ctxp[ctxn];
10606 * This is executed from the parent task context, so
10607 * inherit events that have been marked for cloning.
10608 * First allocate and initialize a context for the
10612 child_ctx = alloc_perf_context(parent_ctx->pmu, child);
10616 child->perf_event_ctxp[ctxn] = child_ctx;
10619 ret = inherit_group(event, parent, parent_ctx,
10623 *inherited_all = 0;
10629 * Initialize the perf_event context in task_struct
10631 static int perf_event_init_context(struct task_struct *child, int ctxn)
10633 struct perf_event_context *child_ctx, *parent_ctx;
10634 struct perf_event_context *cloned_ctx;
10635 struct perf_event *event;
10636 struct task_struct *parent = current;
10637 int inherited_all = 1;
10638 unsigned long flags;
10641 if (likely(!parent->perf_event_ctxp[ctxn]))
10645 * If the parent's context is a clone, pin it so it won't get
10646 * swapped under us.
10648 parent_ctx = perf_pin_task_context(parent, ctxn);
10653 * No need to check if parent_ctx != NULL here; since we saw
10654 * it non-NULL earlier, the only reason for it to become NULL
10655 * is if we exit, and since we're currently in the middle of
10656 * a fork we can't be exiting at the same time.
10660 * Lock the parent list. No need to lock the child - not PID
10661 * hashed yet and not running, so nobody can access it.
10663 mutex_lock(&parent_ctx->mutex);
10666 * We dont have to disable NMIs - we are only looking at
10667 * the list, not manipulating it:
10669 list_for_each_entry(event, &parent_ctx->pinned_groups, group_entry) {
10670 ret = inherit_task_group(event, parent, parent_ctx,
10671 child, ctxn, &inherited_all);
10677 * We can't hold ctx->lock when iterating the ->flexible_group list due
10678 * to allocations, but we need to prevent rotation because
10679 * rotate_ctx() will change the list from interrupt context.
10681 raw_spin_lock_irqsave(&parent_ctx->lock, flags);
10682 parent_ctx->rotate_disable = 1;
10683 raw_spin_unlock_irqrestore(&parent_ctx->lock, flags);
10685 list_for_each_entry(event, &parent_ctx->flexible_groups, group_entry) {
10686 ret = inherit_task_group(event, parent, parent_ctx,
10687 child, ctxn, &inherited_all);
10692 raw_spin_lock_irqsave(&parent_ctx->lock, flags);
10693 parent_ctx->rotate_disable = 0;
10695 child_ctx = child->perf_event_ctxp[ctxn];
10697 if (child_ctx && inherited_all) {
10699 * Mark the child context as a clone of the parent
10700 * context, or of whatever the parent is a clone of.
10702 * Note that if the parent is a clone, the holding of
10703 * parent_ctx->lock avoids it from being uncloned.
10705 cloned_ctx = parent_ctx->parent_ctx;
10707 child_ctx->parent_ctx = cloned_ctx;
10708 child_ctx->parent_gen = parent_ctx->parent_gen;
10710 child_ctx->parent_ctx = parent_ctx;
10711 child_ctx->parent_gen = parent_ctx->generation;
10713 get_ctx(child_ctx->parent_ctx);
10716 raw_spin_unlock_irqrestore(&parent_ctx->lock, flags);
10717 mutex_unlock(&parent_ctx->mutex);
10719 perf_unpin_context(parent_ctx);
10720 put_ctx(parent_ctx);
10726 * Initialize the perf_event context in task_struct
10728 int perf_event_init_task(struct task_struct *child)
10732 memset(child->perf_event_ctxp, 0, sizeof(child->perf_event_ctxp));
10733 mutex_init(&child->perf_event_mutex);
10734 INIT_LIST_HEAD(&child->perf_event_list);
10736 for_each_task_context_nr(ctxn) {
10737 ret = perf_event_init_context(child, ctxn);
10739 perf_event_free_task(child);
10747 static void __init perf_event_init_all_cpus(void)
10749 struct swevent_htable *swhash;
10752 for_each_possible_cpu(cpu) {
10753 swhash = &per_cpu(swevent_htable, cpu);
10754 mutex_init(&swhash->hlist_mutex);
10755 INIT_LIST_HEAD(&per_cpu(active_ctx_list, cpu));
10757 INIT_LIST_HEAD(&per_cpu(pmu_sb_events.list, cpu));
10758 raw_spin_lock_init(&per_cpu(pmu_sb_events.lock, cpu));
10760 #ifdef CONFIG_CGROUP_PERF
10761 INIT_LIST_HEAD(&per_cpu(cgrp_cpuctx_list, cpu));
10763 INIT_LIST_HEAD(&per_cpu(sched_cb_list, cpu));
10767 int perf_event_init_cpu(unsigned int cpu)
10769 struct swevent_htable *swhash = &per_cpu(swevent_htable, cpu);
10771 mutex_lock(&swhash->hlist_mutex);
10772 if (swhash->hlist_refcount > 0 && !swevent_hlist_deref(swhash)) {
10773 struct swevent_hlist *hlist;
10775 hlist = kzalloc_node(sizeof(*hlist), GFP_KERNEL, cpu_to_node(cpu));
10777 rcu_assign_pointer(swhash->swevent_hlist, hlist);
10779 mutex_unlock(&swhash->hlist_mutex);
10783 #if defined CONFIG_HOTPLUG_CPU || defined CONFIG_KEXEC_CORE
10784 static void __perf_event_exit_context(void *__info)
10786 struct perf_event_context *ctx = __info;
10787 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
10788 struct perf_event *event;
10790 raw_spin_lock(&ctx->lock);
10791 list_for_each_entry(event, &ctx->event_list, event_entry)
10792 __perf_remove_from_context(event, cpuctx, ctx, (void *)DETACH_GROUP);
10793 raw_spin_unlock(&ctx->lock);
10796 static void perf_event_exit_cpu_context(int cpu)
10798 struct perf_event_context *ctx;
10802 idx = srcu_read_lock(&pmus_srcu);
10803 list_for_each_entry_rcu(pmu, &pmus, entry) {
10804 ctx = &per_cpu_ptr(pmu->pmu_cpu_context, cpu)->ctx;
10806 mutex_lock(&ctx->mutex);
10807 smp_call_function_single(cpu, __perf_event_exit_context, ctx, 1);
10808 mutex_unlock(&ctx->mutex);
10810 srcu_read_unlock(&pmus_srcu, idx);
10814 static void perf_event_exit_cpu_context(int cpu) { }
10818 int perf_event_exit_cpu(unsigned int cpu)
10820 perf_event_exit_cpu_context(cpu);
10825 perf_reboot(struct notifier_block *notifier, unsigned long val, void *v)
10829 for_each_online_cpu(cpu)
10830 perf_event_exit_cpu(cpu);
10836 * Run the perf reboot notifier at the very last possible moment so that
10837 * the generic watchdog code runs as long as possible.
10839 static struct notifier_block perf_reboot_notifier = {
10840 .notifier_call = perf_reboot,
10841 .priority = INT_MIN,
10844 void __init perf_event_init(void)
10848 idr_init(&pmu_idr);
10850 perf_event_init_all_cpus();
10851 init_srcu_struct(&pmus_srcu);
10852 perf_pmu_register(&perf_swevent, "software", PERF_TYPE_SOFTWARE);
10853 perf_pmu_register(&perf_cpu_clock, NULL, -1);
10854 perf_pmu_register(&perf_task_clock, NULL, -1);
10855 perf_tp_register();
10856 perf_event_init_cpu(smp_processor_id());
10857 register_reboot_notifier(&perf_reboot_notifier);
10859 ret = init_hw_breakpoint();
10860 WARN(ret, "hw_breakpoint initialization failed with: %d", ret);
10863 * Build time assertion that we keep the data_head at the intended
10864 * location. IOW, validation we got the __reserved[] size right.
10866 BUILD_BUG_ON((offsetof(struct perf_event_mmap_page, data_head))
10870 ssize_t perf_event_sysfs_show(struct device *dev, struct device_attribute *attr,
10873 struct perf_pmu_events_attr *pmu_attr =
10874 container_of(attr, struct perf_pmu_events_attr, attr);
10876 if (pmu_attr->event_str)
10877 return sprintf(page, "%s\n", pmu_attr->event_str);
10881 EXPORT_SYMBOL_GPL(perf_event_sysfs_show);
10883 static int __init perf_event_sysfs_init(void)
10888 mutex_lock(&pmus_lock);
10890 ret = bus_register(&pmu_bus);
10894 list_for_each_entry(pmu, &pmus, entry) {
10895 if (!pmu->name || pmu->type < 0)
10898 ret = pmu_dev_alloc(pmu);
10899 WARN(ret, "Failed to register pmu: %s, reason %d\n", pmu->name, ret);
10901 pmu_bus_running = 1;
10905 mutex_unlock(&pmus_lock);
10909 device_initcall(perf_event_sysfs_init);
10911 #ifdef CONFIG_CGROUP_PERF
10912 static struct cgroup_subsys_state *
10913 perf_cgroup_css_alloc(struct cgroup_subsys_state *parent_css)
10915 struct perf_cgroup *jc;
10917 jc = kzalloc(sizeof(*jc), GFP_KERNEL);
10919 return ERR_PTR(-ENOMEM);
10921 jc->info = alloc_percpu(struct perf_cgroup_info);
10924 return ERR_PTR(-ENOMEM);
10930 static void perf_cgroup_css_free(struct cgroup_subsys_state *css)
10932 struct perf_cgroup *jc = container_of(css, struct perf_cgroup, css);
10934 free_percpu(jc->info);
10938 static int __perf_cgroup_move(void *info)
10940 struct task_struct *task = info;
10942 perf_cgroup_switch(task, PERF_CGROUP_SWOUT | PERF_CGROUP_SWIN);
10947 static void perf_cgroup_attach(struct cgroup_taskset *tset)
10949 struct task_struct *task;
10950 struct cgroup_subsys_state *css;
10952 cgroup_taskset_for_each(task, css, tset)
10953 task_function_call(task, __perf_cgroup_move, task);
10956 struct cgroup_subsys perf_event_cgrp_subsys = {
10957 .css_alloc = perf_cgroup_css_alloc,
10958 .css_free = perf_cgroup_css_free,
10959 .attach = perf_cgroup_attach,
10961 * Implicitly enable on dfl hierarchy so that perf events can
10962 * always be filtered by cgroup2 path as long as perf_event
10963 * controller is not mounted on a legacy hierarchy.
10965 .implicit_on_dfl = true,
10967 #endif /* CONFIG_CGROUP_PERF */