2 * Performance events core code:
4 * Copyright (C) 2008 Thomas Gleixner <tglx@linutronix.de>
5 * Copyright (C) 2008-2011 Red Hat, Inc., Ingo Molnar
6 * Copyright (C) 2008-2011 Red Hat, Inc., Peter Zijlstra
7 * Copyright © 2009 Paul Mackerras, IBM Corp. <paulus@au1.ibm.com>
9 * For licensing details see kernel-base/COPYING
14 #include <linux/cpu.h>
15 #include <linux/smp.h>
16 #include <linux/idr.h>
17 #include <linux/file.h>
18 #include <linux/poll.h>
19 #include <linux/slab.h>
20 #include <linux/hash.h>
21 #include <linux/tick.h>
22 #include <linux/sysfs.h>
23 #include <linux/dcache.h>
24 #include <linux/percpu.h>
25 #include <linux/ptrace.h>
26 #include <linux/reboot.h>
27 #include <linux/vmstat.h>
28 #include <linux/device.h>
29 #include <linux/export.h>
30 #include <linux/vmalloc.h>
31 #include <linux/hardirq.h>
32 #include <linux/rculist.h>
33 #include <linux/uaccess.h>
34 #include <linux/syscalls.h>
35 #include <linux/anon_inodes.h>
36 #include <linux/kernel_stat.h>
37 #include <linux/cgroup.h>
38 #include <linux/perf_event.h>
39 #include <linux/trace_events.h>
40 #include <linux/hw_breakpoint.h>
41 #include <linux/mm_types.h>
42 #include <linux/module.h>
43 #include <linux/mman.h>
44 #include <linux/compat.h>
45 #include <linux/bpf.h>
46 #include <linux/filter.h>
47 #include <linux/namei.h>
48 #include <linux/parser.h>
49 #include <linux/sched/clock.h>
50 #include <linux/sched/mm.h>
51 #include <linux/proc_ns.h>
52 #include <linux/mount.h>
56 #include <asm/irq_regs.h>
58 typedef int (*remote_function_f)(void *);
60 struct remote_function_call {
61 struct task_struct *p;
62 remote_function_f func;
67 static void remote_function(void *data)
69 struct remote_function_call *tfc = data;
70 struct task_struct *p = tfc->p;
74 if (task_cpu(p) != smp_processor_id())
78 * Now that we're on right CPU with IRQs disabled, we can test
79 * if we hit the right task without races.
82 tfc->ret = -ESRCH; /* No such (running) process */
87 tfc->ret = tfc->func(tfc->info);
91 * task_function_call - call a function on the cpu on which a task runs
92 * @p: the task to evaluate
93 * @func: the function to be called
94 * @info: the function call argument
96 * Calls the function @func when the task is currently running. This might
97 * be on the current CPU, which just calls the function directly
99 * returns: @func return value, or
100 * -ESRCH - when the process isn't running
101 * -EAGAIN - when the process moved away
104 task_function_call(struct task_struct *p, remote_function_f func, void *info)
106 struct remote_function_call data = {
115 ret = smp_call_function_single(task_cpu(p), remote_function, &data, 1);
118 } while (ret == -EAGAIN);
124 * cpu_function_call - call a function on the cpu
125 * @func: the function to be called
126 * @info: the function call argument
128 * Calls the function @func on the remote cpu.
130 * returns: @func return value or -ENXIO when the cpu is offline
132 static int cpu_function_call(int cpu, remote_function_f func, void *info)
134 struct remote_function_call data = {
138 .ret = -ENXIO, /* No such CPU */
141 smp_call_function_single(cpu, remote_function, &data, 1);
146 static inline struct perf_cpu_context *
147 __get_cpu_context(struct perf_event_context *ctx)
149 return this_cpu_ptr(ctx->pmu->pmu_cpu_context);
152 static void perf_ctx_lock(struct perf_cpu_context *cpuctx,
153 struct perf_event_context *ctx)
155 raw_spin_lock(&cpuctx->ctx.lock);
157 raw_spin_lock(&ctx->lock);
160 static void perf_ctx_unlock(struct perf_cpu_context *cpuctx,
161 struct perf_event_context *ctx)
164 raw_spin_unlock(&ctx->lock);
165 raw_spin_unlock(&cpuctx->ctx.lock);
168 #define TASK_TOMBSTONE ((void *)-1L)
170 static bool is_kernel_event(struct perf_event *event)
172 return READ_ONCE(event->owner) == TASK_TOMBSTONE;
176 * On task ctx scheduling...
178 * When !ctx->nr_events a task context will not be scheduled. This means
179 * we can disable the scheduler hooks (for performance) without leaving
180 * pending task ctx state.
182 * This however results in two special cases:
184 * - removing the last event from a task ctx; this is relatively straight
185 * forward and is done in __perf_remove_from_context.
187 * - adding the first event to a task ctx; this is tricky because we cannot
188 * rely on ctx->is_active and therefore cannot use event_function_call().
189 * See perf_install_in_context().
191 * If ctx->nr_events, then ctx->is_active and cpuctx->task_ctx are set.
194 typedef void (*event_f)(struct perf_event *, struct perf_cpu_context *,
195 struct perf_event_context *, void *);
197 struct event_function_struct {
198 struct perf_event *event;
203 static int event_function(void *info)
205 struct event_function_struct *efs = info;
206 struct perf_event *event = efs->event;
207 struct perf_event_context *ctx = event->ctx;
208 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
209 struct perf_event_context *task_ctx = cpuctx->task_ctx;
212 lockdep_assert_irqs_disabled();
214 perf_ctx_lock(cpuctx, task_ctx);
216 * Since we do the IPI call without holding ctx->lock things can have
217 * changed, double check we hit the task we set out to hit.
220 if (ctx->task != current) {
226 * We only use event_function_call() on established contexts,
227 * and event_function() is only ever called when active (or
228 * rather, we'll have bailed in task_function_call() or the
229 * above ctx->task != current test), therefore we must have
230 * ctx->is_active here.
232 WARN_ON_ONCE(!ctx->is_active);
234 * And since we have ctx->is_active, cpuctx->task_ctx must
237 WARN_ON_ONCE(task_ctx != ctx);
239 WARN_ON_ONCE(&cpuctx->ctx != ctx);
242 efs->func(event, cpuctx, ctx, efs->data);
244 perf_ctx_unlock(cpuctx, task_ctx);
249 static void event_function_call(struct perf_event *event, event_f func, void *data)
251 struct perf_event_context *ctx = event->ctx;
252 struct task_struct *task = READ_ONCE(ctx->task); /* verified in event_function */
253 struct event_function_struct efs = {
259 if (!event->parent) {
261 * If this is a !child event, we must hold ctx::mutex to
262 * stabilize the the event->ctx relation. See
263 * perf_event_ctx_lock().
265 lockdep_assert_held(&ctx->mutex);
269 cpu_function_call(event->cpu, event_function, &efs);
273 if (task == TASK_TOMBSTONE)
277 if (!task_function_call(task, event_function, &efs))
280 raw_spin_lock_irq(&ctx->lock);
282 * Reload the task pointer, it might have been changed by
283 * a concurrent perf_event_context_sched_out().
286 if (task == TASK_TOMBSTONE) {
287 raw_spin_unlock_irq(&ctx->lock);
290 if (ctx->is_active) {
291 raw_spin_unlock_irq(&ctx->lock);
294 func(event, NULL, ctx, data);
295 raw_spin_unlock_irq(&ctx->lock);
299 * Similar to event_function_call() + event_function(), but hard assumes IRQs
300 * are already disabled and we're on the right CPU.
302 static void event_function_local(struct perf_event *event, event_f func, void *data)
304 struct perf_event_context *ctx = event->ctx;
305 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
306 struct task_struct *task = READ_ONCE(ctx->task);
307 struct perf_event_context *task_ctx = NULL;
309 lockdep_assert_irqs_disabled();
312 if (task == TASK_TOMBSTONE)
318 perf_ctx_lock(cpuctx, task_ctx);
321 if (task == TASK_TOMBSTONE)
326 * We must be either inactive or active and the right task,
327 * otherwise we're screwed, since we cannot IPI to somewhere
330 if (ctx->is_active) {
331 if (WARN_ON_ONCE(task != current))
334 if (WARN_ON_ONCE(cpuctx->task_ctx != ctx))
338 WARN_ON_ONCE(&cpuctx->ctx != ctx);
341 func(event, cpuctx, ctx, data);
343 perf_ctx_unlock(cpuctx, task_ctx);
346 #define PERF_FLAG_ALL (PERF_FLAG_FD_NO_GROUP |\
347 PERF_FLAG_FD_OUTPUT |\
348 PERF_FLAG_PID_CGROUP |\
349 PERF_FLAG_FD_CLOEXEC)
352 * branch priv levels that need permission checks
354 #define PERF_SAMPLE_BRANCH_PERM_PLM \
355 (PERF_SAMPLE_BRANCH_KERNEL |\
356 PERF_SAMPLE_BRANCH_HV)
359 EVENT_FLEXIBLE = 0x1,
362 /* see ctx_resched() for details */
364 EVENT_ALL = EVENT_FLEXIBLE | EVENT_PINNED,
368 * perf_sched_events : >0 events exist
369 * perf_cgroup_events: >0 per-cpu cgroup events exist on this cpu
372 static void perf_sched_delayed(struct work_struct *work);
373 DEFINE_STATIC_KEY_FALSE(perf_sched_events);
374 static DECLARE_DELAYED_WORK(perf_sched_work, perf_sched_delayed);
375 static DEFINE_MUTEX(perf_sched_mutex);
376 static atomic_t perf_sched_count;
378 static DEFINE_PER_CPU(atomic_t, perf_cgroup_events);
379 static DEFINE_PER_CPU(int, perf_sched_cb_usages);
380 static DEFINE_PER_CPU(struct pmu_event_list, pmu_sb_events);
382 static atomic_t nr_mmap_events __read_mostly;
383 static atomic_t nr_comm_events __read_mostly;
384 static atomic_t nr_namespaces_events __read_mostly;
385 static atomic_t nr_task_events __read_mostly;
386 static atomic_t nr_freq_events __read_mostly;
387 static atomic_t nr_switch_events __read_mostly;
389 static LIST_HEAD(pmus);
390 static DEFINE_MUTEX(pmus_lock);
391 static struct srcu_struct pmus_srcu;
392 static cpumask_var_t perf_online_mask;
395 * perf event paranoia level:
396 * -1 - not paranoid at all
397 * 0 - disallow raw tracepoint access for unpriv
398 * 1 - disallow cpu events for unpriv
399 * 2 - disallow kernel profiling for unpriv
401 int sysctl_perf_event_paranoid __read_mostly = 2;
403 /* Minimum for 512 kiB + 1 user control page */
404 int sysctl_perf_event_mlock __read_mostly = 512 + (PAGE_SIZE / 1024); /* 'free' kiB per user */
407 * max perf event sample rate
409 #define DEFAULT_MAX_SAMPLE_RATE 100000
410 #define DEFAULT_SAMPLE_PERIOD_NS (NSEC_PER_SEC / DEFAULT_MAX_SAMPLE_RATE)
411 #define DEFAULT_CPU_TIME_MAX_PERCENT 25
413 int sysctl_perf_event_sample_rate __read_mostly = DEFAULT_MAX_SAMPLE_RATE;
415 static int max_samples_per_tick __read_mostly = DIV_ROUND_UP(DEFAULT_MAX_SAMPLE_RATE, HZ);
416 static int perf_sample_period_ns __read_mostly = DEFAULT_SAMPLE_PERIOD_NS;
418 static int perf_sample_allowed_ns __read_mostly =
419 DEFAULT_SAMPLE_PERIOD_NS * DEFAULT_CPU_TIME_MAX_PERCENT / 100;
421 static void update_perf_cpu_limits(void)
423 u64 tmp = perf_sample_period_ns;
425 tmp *= sysctl_perf_cpu_time_max_percent;
426 tmp = div_u64(tmp, 100);
430 WRITE_ONCE(perf_sample_allowed_ns, tmp);
433 static int perf_rotate_context(struct perf_cpu_context *cpuctx);
435 int perf_proc_update_handler(struct ctl_table *table, int write,
436 void __user *buffer, size_t *lenp,
439 int ret = proc_dointvec_minmax(table, write, buffer, lenp, ppos);
445 * If throttling is disabled don't allow the write:
447 if (sysctl_perf_cpu_time_max_percent == 100 ||
448 sysctl_perf_cpu_time_max_percent == 0)
451 max_samples_per_tick = DIV_ROUND_UP(sysctl_perf_event_sample_rate, HZ);
452 perf_sample_period_ns = NSEC_PER_SEC / sysctl_perf_event_sample_rate;
453 update_perf_cpu_limits();
458 int sysctl_perf_cpu_time_max_percent __read_mostly = DEFAULT_CPU_TIME_MAX_PERCENT;
460 int perf_cpu_time_max_percent_handler(struct ctl_table *table, int write,
461 void __user *buffer, size_t *lenp,
464 int ret = proc_dointvec_minmax(table, write, buffer, lenp, ppos);
469 if (sysctl_perf_cpu_time_max_percent == 100 ||
470 sysctl_perf_cpu_time_max_percent == 0) {
472 "perf: Dynamic interrupt throttling disabled, can hang your system!\n");
473 WRITE_ONCE(perf_sample_allowed_ns, 0);
475 update_perf_cpu_limits();
482 * perf samples are done in some very critical code paths (NMIs).
483 * If they take too much CPU time, the system can lock up and not
484 * get any real work done. This will drop the sample rate when
485 * we detect that events are taking too long.
487 #define NR_ACCUMULATED_SAMPLES 128
488 static DEFINE_PER_CPU(u64, running_sample_length);
490 static u64 __report_avg;
491 static u64 __report_allowed;
493 static void perf_duration_warn(struct irq_work *w)
495 printk_ratelimited(KERN_INFO
496 "perf: interrupt took too long (%lld > %lld), lowering "
497 "kernel.perf_event_max_sample_rate to %d\n",
498 __report_avg, __report_allowed,
499 sysctl_perf_event_sample_rate);
502 static DEFINE_IRQ_WORK(perf_duration_work, perf_duration_warn);
504 void perf_sample_event_took(u64 sample_len_ns)
506 u64 max_len = READ_ONCE(perf_sample_allowed_ns);
514 /* Decay the counter by 1 average sample. */
515 running_len = __this_cpu_read(running_sample_length);
516 running_len -= running_len/NR_ACCUMULATED_SAMPLES;
517 running_len += sample_len_ns;
518 __this_cpu_write(running_sample_length, running_len);
521 * Note: this will be biased artifically low until we have
522 * seen NR_ACCUMULATED_SAMPLES. Doing it this way keeps us
523 * from having to maintain a count.
525 avg_len = running_len/NR_ACCUMULATED_SAMPLES;
526 if (avg_len <= max_len)
529 __report_avg = avg_len;
530 __report_allowed = max_len;
533 * Compute a throttle threshold 25% below the current duration.
535 avg_len += avg_len / 4;
536 max = (TICK_NSEC / 100) * sysctl_perf_cpu_time_max_percent;
542 WRITE_ONCE(perf_sample_allowed_ns, avg_len);
543 WRITE_ONCE(max_samples_per_tick, max);
545 sysctl_perf_event_sample_rate = max * HZ;
546 perf_sample_period_ns = NSEC_PER_SEC / sysctl_perf_event_sample_rate;
548 if (!irq_work_queue(&perf_duration_work)) {
549 early_printk("perf: interrupt took too long (%lld > %lld), lowering "
550 "kernel.perf_event_max_sample_rate to %d\n",
551 __report_avg, __report_allowed,
552 sysctl_perf_event_sample_rate);
556 static atomic64_t perf_event_id;
558 static void cpu_ctx_sched_out(struct perf_cpu_context *cpuctx,
559 enum event_type_t event_type);
561 static void cpu_ctx_sched_in(struct perf_cpu_context *cpuctx,
562 enum event_type_t event_type,
563 struct task_struct *task);
565 static void update_context_time(struct perf_event_context *ctx);
566 static u64 perf_event_time(struct perf_event *event);
568 void __weak perf_event_print_debug(void) { }
570 extern __weak const char *perf_pmu_name(void)
575 static inline u64 perf_clock(void)
577 return local_clock();
580 static inline u64 perf_event_clock(struct perf_event *event)
582 return event->clock();
586 * State based event timekeeping...
588 * The basic idea is to use event->state to determine which (if any) time
589 * fields to increment with the current delta. This means we only need to
590 * update timestamps when we change state or when they are explicitly requested
593 * Event groups make things a little more complicated, but not terribly so. The
594 * rules for a group are that if the group leader is OFF the entire group is
595 * OFF, irrespecive of what the group member states are. This results in
596 * __perf_effective_state().
598 * A futher ramification is that when a group leader flips between OFF and
599 * !OFF, we need to update all group member times.
602 * NOTE: perf_event_time() is based on the (cgroup) context time, and thus we
603 * need to make sure the relevant context time is updated before we try and
604 * update our timestamps.
607 static __always_inline enum perf_event_state
608 __perf_effective_state(struct perf_event *event)
610 struct perf_event *leader = event->group_leader;
612 if (leader->state <= PERF_EVENT_STATE_OFF)
613 return leader->state;
618 static __always_inline void
619 __perf_update_times(struct perf_event *event, u64 now, u64 *enabled, u64 *running)
621 enum perf_event_state state = __perf_effective_state(event);
622 u64 delta = now - event->tstamp;
624 *enabled = event->total_time_enabled;
625 if (state >= PERF_EVENT_STATE_INACTIVE)
628 *running = event->total_time_running;
629 if (state >= PERF_EVENT_STATE_ACTIVE)
633 static void perf_event_update_time(struct perf_event *event)
635 u64 now = perf_event_time(event);
637 __perf_update_times(event, now, &event->total_time_enabled,
638 &event->total_time_running);
642 static void perf_event_update_sibling_time(struct perf_event *leader)
644 struct perf_event *sibling;
646 list_for_each_entry(sibling, &leader->sibling_list, group_entry)
647 perf_event_update_time(sibling);
651 perf_event_set_state(struct perf_event *event, enum perf_event_state state)
653 if (event->state == state)
656 perf_event_update_time(event);
658 * If a group leader gets enabled/disabled all its siblings
661 if ((event->state < 0) ^ (state < 0))
662 perf_event_update_sibling_time(event);
664 WRITE_ONCE(event->state, state);
667 #ifdef CONFIG_CGROUP_PERF
670 perf_cgroup_match(struct perf_event *event)
672 struct perf_event_context *ctx = event->ctx;
673 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
675 /* @event doesn't care about cgroup */
679 /* wants specific cgroup scope but @cpuctx isn't associated with any */
684 * Cgroup scoping is recursive. An event enabled for a cgroup is
685 * also enabled for all its descendant cgroups. If @cpuctx's
686 * cgroup is a descendant of @event's (the test covers identity
687 * case), it's a match.
689 return cgroup_is_descendant(cpuctx->cgrp->css.cgroup,
690 event->cgrp->css.cgroup);
693 static inline void perf_detach_cgroup(struct perf_event *event)
695 css_put(&event->cgrp->css);
699 static inline int is_cgroup_event(struct perf_event *event)
701 return event->cgrp != NULL;
704 static inline u64 perf_cgroup_event_time(struct perf_event *event)
706 struct perf_cgroup_info *t;
708 t = per_cpu_ptr(event->cgrp->info, event->cpu);
712 static inline void __update_cgrp_time(struct perf_cgroup *cgrp)
714 struct perf_cgroup_info *info;
719 info = this_cpu_ptr(cgrp->info);
721 info->time += now - info->timestamp;
722 info->timestamp = now;
725 static inline void update_cgrp_time_from_cpuctx(struct perf_cpu_context *cpuctx)
727 struct perf_cgroup *cgrp_out = cpuctx->cgrp;
729 __update_cgrp_time(cgrp_out);
732 static inline void update_cgrp_time_from_event(struct perf_event *event)
734 struct perf_cgroup *cgrp;
737 * ensure we access cgroup data only when needed and
738 * when we know the cgroup is pinned (css_get)
740 if (!is_cgroup_event(event))
743 cgrp = perf_cgroup_from_task(current, event->ctx);
745 * Do not update time when cgroup is not active
747 if (cgroup_is_descendant(cgrp->css.cgroup, event->cgrp->css.cgroup))
748 __update_cgrp_time(event->cgrp);
752 perf_cgroup_set_timestamp(struct task_struct *task,
753 struct perf_event_context *ctx)
755 struct perf_cgroup *cgrp;
756 struct perf_cgroup_info *info;
759 * ctx->lock held by caller
760 * ensure we do not access cgroup data
761 * unless we have the cgroup pinned (css_get)
763 if (!task || !ctx->nr_cgroups)
766 cgrp = perf_cgroup_from_task(task, ctx);
767 info = this_cpu_ptr(cgrp->info);
768 info->timestamp = ctx->timestamp;
771 static DEFINE_PER_CPU(struct list_head, cgrp_cpuctx_list);
773 #define PERF_CGROUP_SWOUT 0x1 /* cgroup switch out every event */
774 #define PERF_CGROUP_SWIN 0x2 /* cgroup switch in events based on task */
777 * reschedule events based on the cgroup constraint of task.
779 * mode SWOUT : schedule out everything
780 * mode SWIN : schedule in based on cgroup for next
782 static void perf_cgroup_switch(struct task_struct *task, int mode)
784 struct perf_cpu_context *cpuctx;
785 struct list_head *list;
789 * Disable interrupts and preemption to avoid this CPU's
790 * cgrp_cpuctx_entry to change under us.
792 local_irq_save(flags);
794 list = this_cpu_ptr(&cgrp_cpuctx_list);
795 list_for_each_entry(cpuctx, list, cgrp_cpuctx_entry) {
796 WARN_ON_ONCE(cpuctx->ctx.nr_cgroups == 0);
798 perf_ctx_lock(cpuctx, cpuctx->task_ctx);
799 perf_pmu_disable(cpuctx->ctx.pmu);
801 if (mode & PERF_CGROUP_SWOUT) {
802 cpu_ctx_sched_out(cpuctx, EVENT_ALL);
804 * must not be done before ctxswout due
805 * to event_filter_match() in event_sched_out()
810 if (mode & PERF_CGROUP_SWIN) {
811 WARN_ON_ONCE(cpuctx->cgrp);
813 * set cgrp before ctxsw in to allow
814 * event_filter_match() to not have to pass
816 * we pass the cpuctx->ctx to perf_cgroup_from_task()
817 * because cgorup events are only per-cpu
819 cpuctx->cgrp = perf_cgroup_from_task(task,
821 cpu_ctx_sched_in(cpuctx, EVENT_ALL, task);
823 perf_pmu_enable(cpuctx->ctx.pmu);
824 perf_ctx_unlock(cpuctx, cpuctx->task_ctx);
827 local_irq_restore(flags);
830 static inline void perf_cgroup_sched_out(struct task_struct *task,
831 struct task_struct *next)
833 struct perf_cgroup *cgrp1;
834 struct perf_cgroup *cgrp2 = NULL;
838 * we come here when we know perf_cgroup_events > 0
839 * we do not need to pass the ctx here because we know
840 * we are holding the rcu lock
842 cgrp1 = perf_cgroup_from_task(task, NULL);
843 cgrp2 = perf_cgroup_from_task(next, NULL);
846 * only schedule out current cgroup events if we know
847 * that we are switching to a different cgroup. Otherwise,
848 * do no touch the cgroup events.
851 perf_cgroup_switch(task, PERF_CGROUP_SWOUT);
856 static inline void perf_cgroup_sched_in(struct task_struct *prev,
857 struct task_struct *task)
859 struct perf_cgroup *cgrp1;
860 struct perf_cgroup *cgrp2 = NULL;
864 * we come here when we know perf_cgroup_events > 0
865 * we do not need to pass the ctx here because we know
866 * we are holding the rcu lock
868 cgrp1 = perf_cgroup_from_task(task, NULL);
869 cgrp2 = perf_cgroup_from_task(prev, NULL);
872 * only need to schedule in cgroup events if we are changing
873 * cgroup during ctxsw. Cgroup events were not scheduled
874 * out of ctxsw out if that was not the case.
877 perf_cgroup_switch(task, PERF_CGROUP_SWIN);
882 static inline int perf_cgroup_connect(int fd, struct perf_event *event,
883 struct perf_event_attr *attr,
884 struct perf_event *group_leader)
886 struct perf_cgroup *cgrp;
887 struct cgroup_subsys_state *css;
888 struct fd f = fdget(fd);
894 css = css_tryget_online_from_dir(f.file->f_path.dentry,
895 &perf_event_cgrp_subsys);
901 cgrp = container_of(css, struct perf_cgroup, css);
905 * all events in a group must monitor
906 * the same cgroup because a task belongs
907 * to only one perf cgroup at a time
909 if (group_leader && group_leader->cgrp != cgrp) {
910 perf_detach_cgroup(event);
919 perf_cgroup_set_shadow_time(struct perf_event *event, u64 now)
921 struct perf_cgroup_info *t;
922 t = per_cpu_ptr(event->cgrp->info, event->cpu);
923 event->shadow_ctx_time = now - t->timestamp;
927 * Update cpuctx->cgrp so that it is set when first cgroup event is added and
928 * cleared when last cgroup event is removed.
931 list_update_cgroup_event(struct perf_event *event,
932 struct perf_event_context *ctx, bool add)
934 struct perf_cpu_context *cpuctx;
935 struct list_head *cpuctx_entry;
937 if (!is_cgroup_event(event))
940 if (add && ctx->nr_cgroups++)
942 else if (!add && --ctx->nr_cgroups)
945 * Because cgroup events are always per-cpu events,
946 * this will always be called from the right CPU.
948 cpuctx = __get_cpu_context(ctx);
949 cpuctx_entry = &cpuctx->cgrp_cpuctx_entry;
950 /* cpuctx->cgrp is NULL unless a cgroup event is active in this CPU .*/
952 struct perf_cgroup *cgrp = perf_cgroup_from_task(current, ctx);
954 list_add(cpuctx_entry, this_cpu_ptr(&cgrp_cpuctx_list));
955 if (cgroup_is_descendant(cgrp->css.cgroup, event->cgrp->css.cgroup))
958 list_del(cpuctx_entry);
963 #else /* !CONFIG_CGROUP_PERF */
966 perf_cgroup_match(struct perf_event *event)
971 static inline void perf_detach_cgroup(struct perf_event *event)
974 static inline int is_cgroup_event(struct perf_event *event)
979 static inline void update_cgrp_time_from_event(struct perf_event *event)
983 static inline void update_cgrp_time_from_cpuctx(struct perf_cpu_context *cpuctx)
987 static inline void perf_cgroup_sched_out(struct task_struct *task,
988 struct task_struct *next)
992 static inline void perf_cgroup_sched_in(struct task_struct *prev,
993 struct task_struct *task)
997 static inline int perf_cgroup_connect(pid_t pid, struct perf_event *event,
998 struct perf_event_attr *attr,
999 struct perf_event *group_leader)
1005 perf_cgroup_set_timestamp(struct task_struct *task,
1006 struct perf_event_context *ctx)
1011 perf_cgroup_switch(struct task_struct *task, struct task_struct *next)
1016 perf_cgroup_set_shadow_time(struct perf_event *event, u64 now)
1020 static inline u64 perf_cgroup_event_time(struct perf_event *event)
1026 list_update_cgroup_event(struct perf_event *event,
1027 struct perf_event_context *ctx, bool add)
1034 * set default to be dependent on timer tick just
1035 * like original code
1037 #define PERF_CPU_HRTIMER (1000 / HZ)
1039 * function must be called with interrupts disabled
1041 static enum hrtimer_restart perf_mux_hrtimer_handler(struct hrtimer *hr)
1043 struct perf_cpu_context *cpuctx;
1046 lockdep_assert_irqs_disabled();
1048 cpuctx = container_of(hr, struct perf_cpu_context, hrtimer);
1049 rotations = perf_rotate_context(cpuctx);
1051 raw_spin_lock(&cpuctx->hrtimer_lock);
1053 hrtimer_forward_now(hr, cpuctx->hrtimer_interval);
1055 cpuctx->hrtimer_active = 0;
1056 raw_spin_unlock(&cpuctx->hrtimer_lock);
1058 return rotations ? HRTIMER_RESTART : HRTIMER_NORESTART;
1061 static void __perf_mux_hrtimer_init(struct perf_cpu_context *cpuctx, int cpu)
1063 struct hrtimer *timer = &cpuctx->hrtimer;
1064 struct pmu *pmu = cpuctx->ctx.pmu;
1067 /* no multiplexing needed for SW PMU */
1068 if (pmu->task_ctx_nr == perf_sw_context)
1072 * check default is sane, if not set then force to
1073 * default interval (1/tick)
1075 interval = pmu->hrtimer_interval_ms;
1077 interval = pmu->hrtimer_interval_ms = PERF_CPU_HRTIMER;
1079 cpuctx->hrtimer_interval = ns_to_ktime(NSEC_PER_MSEC * interval);
1081 raw_spin_lock_init(&cpuctx->hrtimer_lock);
1082 hrtimer_init(timer, CLOCK_MONOTONIC, HRTIMER_MODE_ABS_PINNED);
1083 timer->function = perf_mux_hrtimer_handler;
1086 static int perf_mux_hrtimer_restart(struct perf_cpu_context *cpuctx)
1088 struct hrtimer *timer = &cpuctx->hrtimer;
1089 struct pmu *pmu = cpuctx->ctx.pmu;
1090 unsigned long flags;
1092 /* not for SW PMU */
1093 if (pmu->task_ctx_nr == perf_sw_context)
1096 raw_spin_lock_irqsave(&cpuctx->hrtimer_lock, flags);
1097 if (!cpuctx->hrtimer_active) {
1098 cpuctx->hrtimer_active = 1;
1099 hrtimer_forward_now(timer, cpuctx->hrtimer_interval);
1100 hrtimer_start_expires(timer, HRTIMER_MODE_ABS_PINNED);
1102 raw_spin_unlock_irqrestore(&cpuctx->hrtimer_lock, flags);
1107 void perf_pmu_disable(struct pmu *pmu)
1109 int *count = this_cpu_ptr(pmu->pmu_disable_count);
1111 pmu->pmu_disable(pmu);
1114 void perf_pmu_enable(struct pmu *pmu)
1116 int *count = this_cpu_ptr(pmu->pmu_disable_count);
1118 pmu->pmu_enable(pmu);
1121 static DEFINE_PER_CPU(struct list_head, active_ctx_list);
1124 * perf_event_ctx_activate(), perf_event_ctx_deactivate(), and
1125 * perf_event_task_tick() are fully serialized because they're strictly cpu
1126 * affine and perf_event_ctx{activate,deactivate} are called with IRQs
1127 * disabled, while perf_event_task_tick is called from IRQ context.
1129 static void perf_event_ctx_activate(struct perf_event_context *ctx)
1131 struct list_head *head = this_cpu_ptr(&active_ctx_list);
1133 lockdep_assert_irqs_disabled();
1135 WARN_ON(!list_empty(&ctx->active_ctx_list));
1137 list_add(&ctx->active_ctx_list, head);
1140 static void perf_event_ctx_deactivate(struct perf_event_context *ctx)
1142 lockdep_assert_irqs_disabled();
1144 WARN_ON(list_empty(&ctx->active_ctx_list));
1146 list_del_init(&ctx->active_ctx_list);
1149 static void get_ctx(struct perf_event_context *ctx)
1151 WARN_ON(!atomic_inc_not_zero(&ctx->refcount));
1154 static void free_ctx(struct rcu_head *head)
1156 struct perf_event_context *ctx;
1158 ctx = container_of(head, struct perf_event_context, rcu_head);
1159 kfree(ctx->task_ctx_data);
1163 static void put_ctx(struct perf_event_context *ctx)
1165 if (atomic_dec_and_test(&ctx->refcount)) {
1166 if (ctx->parent_ctx)
1167 put_ctx(ctx->parent_ctx);
1168 if (ctx->task && ctx->task != TASK_TOMBSTONE)
1169 put_task_struct(ctx->task);
1170 call_rcu(&ctx->rcu_head, free_ctx);
1175 * Because of perf_event::ctx migration in sys_perf_event_open::move_group and
1176 * perf_pmu_migrate_context() we need some magic.
1178 * Those places that change perf_event::ctx will hold both
1179 * perf_event_ctx::mutex of the 'old' and 'new' ctx value.
1181 * Lock ordering is by mutex address. There are two other sites where
1182 * perf_event_context::mutex nests and those are:
1184 * - perf_event_exit_task_context() [ child , 0 ]
1185 * perf_event_exit_event()
1186 * put_event() [ parent, 1 ]
1188 * - perf_event_init_context() [ parent, 0 ]
1189 * inherit_task_group()
1192 * perf_event_alloc()
1194 * perf_try_init_event() [ child , 1 ]
1196 * While it appears there is an obvious deadlock here -- the parent and child
1197 * nesting levels are inverted between the two. This is in fact safe because
1198 * life-time rules separate them. That is an exiting task cannot fork, and a
1199 * spawning task cannot (yet) exit.
1201 * But remember that that these are parent<->child context relations, and
1202 * migration does not affect children, therefore these two orderings should not
1205 * The change in perf_event::ctx does not affect children (as claimed above)
1206 * because the sys_perf_event_open() case will install a new event and break
1207 * the ctx parent<->child relation, and perf_pmu_migrate_context() is only
1208 * concerned with cpuctx and that doesn't have children.
1210 * The places that change perf_event::ctx will issue:
1212 * perf_remove_from_context();
1213 * synchronize_rcu();
1214 * perf_install_in_context();
1216 * to affect the change. The remove_from_context() + synchronize_rcu() should
1217 * quiesce the event, after which we can install it in the new location. This
1218 * means that only external vectors (perf_fops, prctl) can perturb the event
1219 * while in transit. Therefore all such accessors should also acquire
1220 * perf_event_context::mutex to serialize against this.
1222 * However; because event->ctx can change while we're waiting to acquire
1223 * ctx->mutex we must be careful and use the below perf_event_ctx_lock()
1228 * task_struct::perf_event_mutex
1229 * perf_event_context::mutex
1230 * perf_event::child_mutex;
1231 * perf_event_context::lock
1232 * perf_event::mmap_mutex
1237 * cpuctx->mutex / perf_event_context::mutex
1239 static struct perf_event_context *
1240 perf_event_ctx_lock_nested(struct perf_event *event, int nesting)
1242 struct perf_event_context *ctx;
1246 ctx = READ_ONCE(event->ctx);
1247 if (!atomic_inc_not_zero(&ctx->refcount)) {
1253 mutex_lock_nested(&ctx->mutex, nesting);
1254 if (event->ctx != ctx) {
1255 mutex_unlock(&ctx->mutex);
1263 static inline struct perf_event_context *
1264 perf_event_ctx_lock(struct perf_event *event)
1266 return perf_event_ctx_lock_nested(event, 0);
1269 static void perf_event_ctx_unlock(struct perf_event *event,
1270 struct perf_event_context *ctx)
1272 mutex_unlock(&ctx->mutex);
1277 * This must be done under the ctx->lock, such as to serialize against
1278 * context_equiv(), therefore we cannot call put_ctx() since that might end up
1279 * calling scheduler related locks and ctx->lock nests inside those.
1281 static __must_check struct perf_event_context *
1282 unclone_ctx(struct perf_event_context *ctx)
1284 struct perf_event_context *parent_ctx = ctx->parent_ctx;
1286 lockdep_assert_held(&ctx->lock);
1289 ctx->parent_ctx = NULL;
1295 static u32 perf_event_pid_type(struct perf_event *event, struct task_struct *p,
1300 * only top level events have the pid namespace they were created in
1303 event = event->parent;
1305 nr = __task_pid_nr_ns(p, type, event->ns);
1306 /* avoid -1 if it is idle thread or runs in another ns */
1307 if (!nr && !pid_alive(p))
1312 static u32 perf_event_pid(struct perf_event *event, struct task_struct *p)
1314 return perf_event_pid_type(event, p, __PIDTYPE_TGID);
1317 static u32 perf_event_tid(struct perf_event *event, struct task_struct *p)
1319 return perf_event_pid_type(event, p, PIDTYPE_PID);
1323 * If we inherit events we want to return the parent event id
1326 static u64 primary_event_id(struct perf_event *event)
1331 id = event->parent->id;
1337 * Get the perf_event_context for a task and lock it.
1339 * This has to cope with with the fact that until it is locked,
1340 * the context could get moved to another task.
1342 static struct perf_event_context *
1343 perf_lock_task_context(struct task_struct *task, int ctxn, unsigned long *flags)
1345 struct perf_event_context *ctx;
1349 * One of the few rules of preemptible RCU is that one cannot do
1350 * rcu_read_unlock() while holding a scheduler (or nested) lock when
1351 * part of the read side critical section was irqs-enabled -- see
1352 * rcu_read_unlock_special().
1354 * Since ctx->lock nests under rq->lock we must ensure the entire read
1355 * side critical section has interrupts disabled.
1357 local_irq_save(*flags);
1359 ctx = rcu_dereference(task->perf_event_ctxp[ctxn]);
1362 * If this context is a clone of another, it might
1363 * get swapped for another underneath us by
1364 * perf_event_task_sched_out, though the
1365 * rcu_read_lock() protects us from any context
1366 * getting freed. Lock the context and check if it
1367 * got swapped before we could get the lock, and retry
1368 * if so. If we locked the right context, then it
1369 * can't get swapped on us any more.
1371 raw_spin_lock(&ctx->lock);
1372 if (ctx != rcu_dereference(task->perf_event_ctxp[ctxn])) {
1373 raw_spin_unlock(&ctx->lock);
1375 local_irq_restore(*flags);
1379 if (ctx->task == TASK_TOMBSTONE ||
1380 !atomic_inc_not_zero(&ctx->refcount)) {
1381 raw_spin_unlock(&ctx->lock);
1384 WARN_ON_ONCE(ctx->task != task);
1389 local_irq_restore(*flags);
1394 * Get the context for a task and increment its pin_count so it
1395 * can't get swapped to another task. This also increments its
1396 * reference count so that the context can't get freed.
1398 static struct perf_event_context *
1399 perf_pin_task_context(struct task_struct *task, int ctxn)
1401 struct perf_event_context *ctx;
1402 unsigned long flags;
1404 ctx = perf_lock_task_context(task, ctxn, &flags);
1407 raw_spin_unlock_irqrestore(&ctx->lock, flags);
1412 static void perf_unpin_context(struct perf_event_context *ctx)
1414 unsigned long flags;
1416 raw_spin_lock_irqsave(&ctx->lock, flags);
1418 raw_spin_unlock_irqrestore(&ctx->lock, flags);
1422 * Update the record of the current time in a context.
1424 static void update_context_time(struct perf_event_context *ctx)
1426 u64 now = perf_clock();
1428 ctx->time += now - ctx->timestamp;
1429 ctx->timestamp = now;
1432 static u64 perf_event_time(struct perf_event *event)
1434 struct perf_event_context *ctx = event->ctx;
1436 if (is_cgroup_event(event))
1437 return perf_cgroup_event_time(event);
1439 return ctx ? ctx->time : 0;
1442 static enum event_type_t get_event_type(struct perf_event *event)
1444 struct perf_event_context *ctx = event->ctx;
1445 enum event_type_t event_type;
1447 lockdep_assert_held(&ctx->lock);
1450 * It's 'group type', really, because if our group leader is
1451 * pinned, so are we.
1453 if (event->group_leader != event)
1454 event = event->group_leader;
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;
1484 event->tstamp = perf_event_time(event);
1487 * If we're a stand alone event or group leader, we go to the context
1488 * list, group events are kept attached to the group so that
1489 * perf_group_detach can, at all times, locate all siblings.
1491 if (event->group_leader == event) {
1492 struct list_head *list;
1494 event->group_caps = event->event_caps;
1496 list = ctx_group_list(event, ctx);
1497 list_add_tail(&event->group_entry, list);
1500 list_update_cgroup_event(event, ctx, true);
1502 list_add_rcu(&event->event_entry, &ctx->event_list);
1504 if (event->attr.inherit_stat)
1511 * Initialize event state based on the perf_event_attr::disabled.
1513 static inline void perf_event__state_init(struct perf_event *event)
1515 event->state = event->attr.disabled ? PERF_EVENT_STATE_OFF :
1516 PERF_EVENT_STATE_INACTIVE;
1519 static void __perf_event_read_size(struct perf_event *event, int nr_siblings)
1521 int entry = sizeof(u64); /* value */
1525 if (event->attr.read_format & PERF_FORMAT_TOTAL_TIME_ENABLED)
1526 size += sizeof(u64);
1528 if (event->attr.read_format & PERF_FORMAT_TOTAL_TIME_RUNNING)
1529 size += sizeof(u64);
1531 if (event->attr.read_format & PERF_FORMAT_ID)
1532 entry += sizeof(u64);
1534 if (event->attr.read_format & PERF_FORMAT_GROUP) {
1536 size += sizeof(u64);
1540 event->read_size = size;
1543 static void __perf_event_header_size(struct perf_event *event, u64 sample_type)
1545 struct perf_sample_data *data;
1548 if (sample_type & PERF_SAMPLE_IP)
1549 size += sizeof(data->ip);
1551 if (sample_type & PERF_SAMPLE_ADDR)
1552 size += sizeof(data->addr);
1554 if (sample_type & PERF_SAMPLE_PERIOD)
1555 size += sizeof(data->period);
1557 if (sample_type & PERF_SAMPLE_WEIGHT)
1558 size += sizeof(data->weight);
1560 if (sample_type & PERF_SAMPLE_READ)
1561 size += event->read_size;
1563 if (sample_type & PERF_SAMPLE_DATA_SRC)
1564 size += sizeof(data->data_src.val);
1566 if (sample_type & PERF_SAMPLE_TRANSACTION)
1567 size += sizeof(data->txn);
1569 if (sample_type & PERF_SAMPLE_PHYS_ADDR)
1570 size += sizeof(data->phys_addr);
1572 event->header_size = size;
1576 * Called at perf_event creation and when events are attached/detached from a
1579 static void perf_event__header_size(struct perf_event *event)
1581 __perf_event_read_size(event,
1582 event->group_leader->nr_siblings);
1583 __perf_event_header_size(event, event->attr.sample_type);
1586 static void perf_event__id_header_size(struct perf_event *event)
1588 struct perf_sample_data *data;
1589 u64 sample_type = event->attr.sample_type;
1592 if (sample_type & PERF_SAMPLE_TID)
1593 size += sizeof(data->tid_entry);
1595 if (sample_type & PERF_SAMPLE_TIME)
1596 size += sizeof(data->time);
1598 if (sample_type & PERF_SAMPLE_IDENTIFIER)
1599 size += sizeof(data->id);
1601 if (sample_type & PERF_SAMPLE_ID)
1602 size += sizeof(data->id);
1604 if (sample_type & PERF_SAMPLE_STREAM_ID)
1605 size += sizeof(data->stream_id);
1607 if (sample_type & PERF_SAMPLE_CPU)
1608 size += sizeof(data->cpu_entry);
1610 event->id_header_size = size;
1613 static bool perf_event_validate_size(struct perf_event *event)
1616 * The values computed here will be over-written when we actually
1619 __perf_event_read_size(event, event->group_leader->nr_siblings + 1);
1620 __perf_event_header_size(event, event->attr.sample_type & ~PERF_SAMPLE_READ);
1621 perf_event__id_header_size(event);
1624 * Sum the lot; should not exceed the 64k limit we have on records.
1625 * Conservative limit to allow for callchains and other variable fields.
1627 if (event->read_size + event->header_size +
1628 event->id_header_size + sizeof(struct perf_event_header) >= 16*1024)
1634 static void perf_group_attach(struct perf_event *event)
1636 struct perf_event *group_leader = event->group_leader, *pos;
1638 lockdep_assert_held(&event->ctx->lock);
1641 * We can have double attach due to group movement in perf_event_open.
1643 if (event->attach_state & PERF_ATTACH_GROUP)
1646 event->attach_state |= PERF_ATTACH_GROUP;
1648 if (group_leader == event)
1651 WARN_ON_ONCE(group_leader->ctx != event->ctx);
1653 group_leader->group_caps &= event->event_caps;
1655 list_add_tail(&event->group_entry, &group_leader->sibling_list);
1656 group_leader->nr_siblings++;
1658 perf_event__header_size(group_leader);
1660 list_for_each_entry(pos, &group_leader->sibling_list, group_entry)
1661 perf_event__header_size(pos);
1665 * Remove a event from the lists for its context.
1666 * Must be called with ctx->mutex and ctx->lock held.
1669 list_del_event(struct perf_event *event, struct perf_event_context *ctx)
1671 WARN_ON_ONCE(event->ctx != ctx);
1672 lockdep_assert_held(&ctx->lock);
1675 * We can have double detach due to exit/hot-unplug + close.
1677 if (!(event->attach_state & PERF_ATTACH_CONTEXT))
1680 event->attach_state &= ~PERF_ATTACH_CONTEXT;
1682 list_update_cgroup_event(event, ctx, false);
1685 if (event->attr.inherit_stat)
1688 list_del_rcu(&event->event_entry);
1690 if (event->group_leader == event)
1691 list_del_init(&event->group_entry);
1694 * If event was in error state, then keep it
1695 * that way, otherwise bogus counts will be
1696 * returned on read(). The only way to get out
1697 * of error state is by explicit re-enabling
1700 if (event->state > PERF_EVENT_STATE_OFF)
1701 perf_event_set_state(event, PERF_EVENT_STATE_OFF);
1706 static void perf_group_detach(struct perf_event *event)
1708 struct perf_event *sibling, *tmp;
1709 struct list_head *list = NULL;
1711 lockdep_assert_held(&event->ctx->lock);
1714 * We can have double detach due to exit/hot-unplug + close.
1716 if (!(event->attach_state & PERF_ATTACH_GROUP))
1719 event->attach_state &= ~PERF_ATTACH_GROUP;
1722 * If this is a sibling, remove it from its group.
1724 if (event->group_leader != event) {
1725 list_del_init(&event->group_entry);
1726 event->group_leader->nr_siblings--;
1730 if (!list_empty(&event->group_entry))
1731 list = &event->group_entry;
1734 * If this was a group event with sibling events then
1735 * upgrade the siblings to singleton events by adding them
1736 * to whatever list we are on.
1738 list_for_each_entry_safe(sibling, tmp, &event->sibling_list, group_entry) {
1740 list_move_tail(&sibling->group_entry, list);
1741 sibling->group_leader = sibling;
1743 /* Inherit group flags from the previous leader */
1744 sibling->group_caps = event->group_caps;
1746 WARN_ON_ONCE(sibling->ctx != event->ctx);
1750 perf_event__header_size(event->group_leader);
1752 list_for_each_entry(tmp, &event->group_leader->sibling_list, group_entry)
1753 perf_event__header_size(tmp);
1756 static bool is_orphaned_event(struct perf_event *event)
1758 return event->state == PERF_EVENT_STATE_DEAD;
1761 static inline int __pmu_filter_match(struct perf_event *event)
1763 struct pmu *pmu = event->pmu;
1764 return pmu->filter_match ? pmu->filter_match(event) : 1;
1768 * Check whether we should attempt to schedule an event group based on
1769 * PMU-specific filtering. An event group can consist of HW and SW events,
1770 * potentially with a SW leader, so we must check all the filters, to
1771 * determine whether a group is schedulable:
1773 static inline int pmu_filter_match(struct perf_event *event)
1775 struct perf_event *child;
1777 if (!__pmu_filter_match(event))
1780 list_for_each_entry(child, &event->sibling_list, group_entry) {
1781 if (!__pmu_filter_match(child))
1789 event_filter_match(struct perf_event *event)
1791 return (event->cpu == -1 || event->cpu == smp_processor_id()) &&
1792 perf_cgroup_match(event) && pmu_filter_match(event);
1796 event_sched_out(struct perf_event *event,
1797 struct perf_cpu_context *cpuctx,
1798 struct perf_event_context *ctx)
1800 enum perf_event_state state = PERF_EVENT_STATE_INACTIVE;
1802 WARN_ON_ONCE(event->ctx != ctx);
1803 lockdep_assert_held(&ctx->lock);
1805 if (event->state != PERF_EVENT_STATE_ACTIVE)
1808 perf_pmu_disable(event->pmu);
1810 event->pmu->del(event, 0);
1813 if (event->pending_disable) {
1814 event->pending_disable = 0;
1815 state = PERF_EVENT_STATE_OFF;
1817 perf_event_set_state(event, state);
1819 if (!is_software_event(event))
1820 cpuctx->active_oncpu--;
1821 if (!--ctx->nr_active)
1822 perf_event_ctx_deactivate(ctx);
1823 if (event->attr.freq && event->attr.sample_freq)
1825 if (event->attr.exclusive || !cpuctx->active_oncpu)
1826 cpuctx->exclusive = 0;
1828 perf_pmu_enable(event->pmu);
1832 group_sched_out(struct perf_event *group_event,
1833 struct perf_cpu_context *cpuctx,
1834 struct perf_event_context *ctx)
1836 struct perf_event *event;
1838 if (group_event->state != PERF_EVENT_STATE_ACTIVE)
1841 perf_pmu_disable(ctx->pmu);
1843 event_sched_out(group_event, cpuctx, ctx);
1846 * Schedule out siblings (if any):
1848 list_for_each_entry(event, &group_event->sibling_list, group_entry)
1849 event_sched_out(event, cpuctx, ctx);
1851 perf_pmu_enable(ctx->pmu);
1853 if (group_event->attr.exclusive)
1854 cpuctx->exclusive = 0;
1857 #define DETACH_GROUP 0x01UL
1860 * Cross CPU call to remove a performance event
1862 * We disable the event on the hardware level first. After that we
1863 * remove it from the context list.
1866 __perf_remove_from_context(struct perf_event *event,
1867 struct perf_cpu_context *cpuctx,
1868 struct perf_event_context *ctx,
1871 unsigned long flags = (unsigned long)info;
1873 if (ctx->is_active & EVENT_TIME) {
1874 update_context_time(ctx);
1875 update_cgrp_time_from_cpuctx(cpuctx);
1878 event_sched_out(event, cpuctx, ctx);
1879 if (flags & DETACH_GROUP)
1880 perf_group_detach(event);
1881 list_del_event(event, ctx);
1883 if (!ctx->nr_events && ctx->is_active) {
1886 WARN_ON_ONCE(cpuctx->task_ctx != ctx);
1887 cpuctx->task_ctx = NULL;
1893 * Remove the event from a task's (or a CPU's) list of events.
1895 * If event->ctx is a cloned context, callers must make sure that
1896 * every task struct that event->ctx->task could possibly point to
1897 * remains valid. This is OK when called from perf_release since
1898 * that only calls us on the top-level context, which can't be a clone.
1899 * When called from perf_event_exit_task, it's OK because the
1900 * context has been detached from its task.
1902 static void perf_remove_from_context(struct perf_event *event, unsigned long flags)
1904 struct perf_event_context *ctx = event->ctx;
1906 lockdep_assert_held(&ctx->mutex);
1908 event_function_call(event, __perf_remove_from_context, (void *)flags);
1911 * The above event_function_call() can NO-OP when it hits
1912 * TASK_TOMBSTONE. In that case we must already have been detached
1913 * from the context (by perf_event_exit_event()) but the grouping
1914 * might still be in-tact.
1916 WARN_ON_ONCE(event->attach_state & PERF_ATTACH_CONTEXT);
1917 if ((flags & DETACH_GROUP) &&
1918 (event->attach_state & PERF_ATTACH_GROUP)) {
1920 * Since in that case we cannot possibly be scheduled, simply
1923 raw_spin_lock_irq(&ctx->lock);
1924 perf_group_detach(event);
1925 raw_spin_unlock_irq(&ctx->lock);
1930 * Cross CPU call to disable a performance event
1932 static void __perf_event_disable(struct perf_event *event,
1933 struct perf_cpu_context *cpuctx,
1934 struct perf_event_context *ctx,
1937 if (event->state < PERF_EVENT_STATE_INACTIVE)
1940 if (ctx->is_active & EVENT_TIME) {
1941 update_context_time(ctx);
1942 update_cgrp_time_from_event(event);
1945 if (event == event->group_leader)
1946 group_sched_out(event, cpuctx, ctx);
1948 event_sched_out(event, cpuctx, ctx);
1950 perf_event_set_state(event, PERF_EVENT_STATE_OFF);
1956 * If event->ctx is a cloned context, callers must make sure that
1957 * every task struct that event->ctx->task could possibly point to
1958 * remains valid. This condition is satisifed when called through
1959 * perf_event_for_each_child or perf_event_for_each because they
1960 * hold the top-level event's child_mutex, so any descendant that
1961 * goes to exit will block in perf_event_exit_event().
1963 * When called from perf_pending_event it's OK because event->ctx
1964 * is the current context on this CPU and preemption is disabled,
1965 * hence we can't get into perf_event_task_sched_out for this context.
1967 static void _perf_event_disable(struct perf_event *event)
1969 struct perf_event_context *ctx = event->ctx;
1971 raw_spin_lock_irq(&ctx->lock);
1972 if (event->state <= PERF_EVENT_STATE_OFF) {
1973 raw_spin_unlock_irq(&ctx->lock);
1976 raw_spin_unlock_irq(&ctx->lock);
1978 event_function_call(event, __perf_event_disable, NULL);
1981 void perf_event_disable_local(struct perf_event *event)
1983 event_function_local(event, __perf_event_disable, NULL);
1987 * Strictly speaking kernel users cannot create groups and therefore this
1988 * interface does not need the perf_event_ctx_lock() magic.
1990 void perf_event_disable(struct perf_event *event)
1992 struct perf_event_context *ctx;
1994 ctx = perf_event_ctx_lock(event);
1995 _perf_event_disable(event);
1996 perf_event_ctx_unlock(event, ctx);
1998 EXPORT_SYMBOL_GPL(perf_event_disable);
2000 void perf_event_disable_inatomic(struct perf_event *event)
2002 event->pending_disable = 1;
2003 irq_work_queue(&event->pending);
2006 static void perf_set_shadow_time(struct perf_event *event,
2007 struct perf_event_context *ctx)
2010 * use the correct time source for the time snapshot
2012 * We could get by without this by leveraging the
2013 * fact that to get to this function, the caller
2014 * has most likely already called update_context_time()
2015 * and update_cgrp_time_xx() and thus both timestamp
2016 * are identical (or very close). Given that tstamp is,
2017 * already adjusted for cgroup, we could say that:
2018 * tstamp - ctx->timestamp
2020 * tstamp - cgrp->timestamp.
2022 * Then, in perf_output_read(), the calculation would
2023 * work with no changes because:
2024 * - event is guaranteed scheduled in
2025 * - no scheduled out in between
2026 * - thus the timestamp would be the same
2028 * But this is a bit hairy.
2030 * So instead, we have an explicit cgroup call to remain
2031 * within the time time source all along. We believe it
2032 * is cleaner and simpler to understand.
2034 if (is_cgroup_event(event))
2035 perf_cgroup_set_shadow_time(event, event->tstamp);
2037 event->shadow_ctx_time = event->tstamp - ctx->timestamp;
2040 #define MAX_INTERRUPTS (~0ULL)
2042 static void perf_log_throttle(struct perf_event *event, int enable);
2043 static void perf_log_itrace_start(struct perf_event *event);
2046 event_sched_in(struct perf_event *event,
2047 struct perf_cpu_context *cpuctx,
2048 struct perf_event_context *ctx)
2052 lockdep_assert_held(&ctx->lock);
2054 if (event->state <= PERF_EVENT_STATE_OFF)
2057 WRITE_ONCE(event->oncpu, smp_processor_id());
2059 * Order event::oncpu write to happen before the ACTIVE state is
2060 * visible. This allows perf_event_{stop,read}() to observe the correct
2061 * ->oncpu if it sees ACTIVE.
2064 perf_event_set_state(event, PERF_EVENT_STATE_ACTIVE);
2067 * Unthrottle events, since we scheduled we might have missed several
2068 * ticks already, also for a heavily scheduling task there is little
2069 * guarantee it'll get a tick in a timely manner.
2071 if (unlikely(event->hw.interrupts == MAX_INTERRUPTS)) {
2072 perf_log_throttle(event, 1);
2073 event->hw.interrupts = 0;
2076 perf_pmu_disable(event->pmu);
2078 perf_set_shadow_time(event, ctx);
2080 perf_log_itrace_start(event);
2082 if (event->pmu->add(event, PERF_EF_START)) {
2083 perf_event_set_state(event, PERF_EVENT_STATE_INACTIVE);
2089 if (!is_software_event(event))
2090 cpuctx->active_oncpu++;
2091 if (!ctx->nr_active++)
2092 perf_event_ctx_activate(ctx);
2093 if (event->attr.freq && event->attr.sample_freq)
2096 if (event->attr.exclusive)
2097 cpuctx->exclusive = 1;
2100 perf_pmu_enable(event->pmu);
2106 group_sched_in(struct perf_event *group_event,
2107 struct perf_cpu_context *cpuctx,
2108 struct perf_event_context *ctx)
2110 struct perf_event *event, *partial_group = NULL;
2111 struct pmu *pmu = ctx->pmu;
2113 if (group_event->state == PERF_EVENT_STATE_OFF)
2116 pmu->start_txn(pmu, PERF_PMU_TXN_ADD);
2118 if (event_sched_in(group_event, cpuctx, ctx)) {
2119 pmu->cancel_txn(pmu);
2120 perf_mux_hrtimer_restart(cpuctx);
2125 * Schedule in siblings as one group (if any):
2127 list_for_each_entry(event, &group_event->sibling_list, group_entry) {
2128 if (event_sched_in(event, cpuctx, ctx)) {
2129 partial_group = event;
2134 if (!pmu->commit_txn(pmu))
2139 * Groups can be scheduled in as one unit only, so undo any
2140 * partial group before returning:
2141 * The events up to the failed event are scheduled out normally.
2143 list_for_each_entry(event, &group_event->sibling_list, group_entry) {
2144 if (event == partial_group)
2147 event_sched_out(event, cpuctx, ctx);
2149 event_sched_out(group_event, cpuctx, ctx);
2151 pmu->cancel_txn(pmu);
2153 perf_mux_hrtimer_restart(cpuctx);
2159 * Work out whether we can put this event group on the CPU now.
2161 static int group_can_go_on(struct perf_event *event,
2162 struct perf_cpu_context *cpuctx,
2166 * Groups consisting entirely of software events can always go on.
2168 if (event->group_caps & PERF_EV_CAP_SOFTWARE)
2171 * If an exclusive group is already on, no other hardware
2174 if (cpuctx->exclusive)
2177 * If this group is exclusive and there are already
2178 * events on the CPU, it can't go on.
2180 if (event->attr.exclusive && cpuctx->active_oncpu)
2183 * Otherwise, try to add it if all previous groups were able
2189 static void add_event_to_ctx(struct perf_event *event,
2190 struct perf_event_context *ctx)
2192 list_add_event(event, ctx);
2193 perf_group_attach(event);
2196 static void ctx_sched_out(struct perf_event_context *ctx,
2197 struct perf_cpu_context *cpuctx,
2198 enum event_type_t event_type);
2200 ctx_sched_in(struct perf_event_context *ctx,
2201 struct perf_cpu_context *cpuctx,
2202 enum event_type_t event_type,
2203 struct task_struct *task);
2205 static void task_ctx_sched_out(struct perf_cpu_context *cpuctx,
2206 struct perf_event_context *ctx,
2207 enum event_type_t event_type)
2209 if (!cpuctx->task_ctx)
2212 if (WARN_ON_ONCE(ctx != cpuctx->task_ctx))
2215 ctx_sched_out(ctx, cpuctx, event_type);
2218 static void perf_event_sched_in(struct perf_cpu_context *cpuctx,
2219 struct perf_event_context *ctx,
2220 struct task_struct *task)
2222 cpu_ctx_sched_in(cpuctx, EVENT_PINNED, task);
2224 ctx_sched_in(ctx, cpuctx, EVENT_PINNED, task);
2225 cpu_ctx_sched_in(cpuctx, EVENT_FLEXIBLE, task);
2227 ctx_sched_in(ctx, cpuctx, EVENT_FLEXIBLE, task);
2231 * We want to maintain the following priority of scheduling:
2232 * - CPU pinned (EVENT_CPU | EVENT_PINNED)
2233 * - task pinned (EVENT_PINNED)
2234 * - CPU flexible (EVENT_CPU | EVENT_FLEXIBLE)
2235 * - task flexible (EVENT_FLEXIBLE).
2237 * In order to avoid unscheduling and scheduling back in everything every
2238 * time an event is added, only do it for the groups of equal priority and
2241 * This can be called after a batch operation on task events, in which case
2242 * event_type is a bit mask of the types of events involved. For CPU events,
2243 * event_type is only either EVENT_PINNED or EVENT_FLEXIBLE.
2245 static void ctx_resched(struct perf_cpu_context *cpuctx,
2246 struct perf_event_context *task_ctx,
2247 enum event_type_t event_type)
2249 enum event_type_t ctx_event_type;
2250 bool cpu_event = !!(event_type & EVENT_CPU);
2253 * If pinned groups are involved, flexible groups also need to be
2256 if (event_type & EVENT_PINNED)
2257 event_type |= EVENT_FLEXIBLE;
2259 ctx_event_type = event_type & EVENT_ALL;
2261 perf_pmu_disable(cpuctx->ctx.pmu);
2263 task_ctx_sched_out(cpuctx, task_ctx, event_type);
2266 * Decide which cpu ctx groups to schedule out based on the types
2267 * of events that caused rescheduling:
2268 * - EVENT_CPU: schedule out corresponding groups;
2269 * - EVENT_PINNED task events: schedule out EVENT_FLEXIBLE groups;
2270 * - otherwise, do nothing more.
2273 cpu_ctx_sched_out(cpuctx, ctx_event_type);
2274 else if (ctx_event_type & EVENT_PINNED)
2275 cpu_ctx_sched_out(cpuctx, EVENT_FLEXIBLE);
2277 perf_event_sched_in(cpuctx, task_ctx, current);
2278 perf_pmu_enable(cpuctx->ctx.pmu);
2282 * Cross CPU call to install and enable a performance event
2284 * Very similar to remote_function() + event_function() but cannot assume that
2285 * things like ctx->is_active and cpuctx->task_ctx are set.
2287 static int __perf_install_in_context(void *info)
2289 struct perf_event *event = info;
2290 struct perf_event_context *ctx = event->ctx;
2291 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
2292 struct perf_event_context *task_ctx = cpuctx->task_ctx;
2293 bool reprogram = true;
2296 raw_spin_lock(&cpuctx->ctx.lock);
2298 raw_spin_lock(&ctx->lock);
2301 reprogram = (ctx->task == current);
2304 * If the task is running, it must be running on this CPU,
2305 * otherwise we cannot reprogram things.
2307 * If its not running, we don't care, ctx->lock will
2308 * serialize against it becoming runnable.
2310 if (task_curr(ctx->task) && !reprogram) {
2315 WARN_ON_ONCE(reprogram && cpuctx->task_ctx && cpuctx->task_ctx != ctx);
2316 } else if (task_ctx) {
2317 raw_spin_lock(&task_ctx->lock);
2321 ctx_sched_out(ctx, cpuctx, EVENT_TIME);
2322 add_event_to_ctx(event, ctx);
2323 ctx_resched(cpuctx, task_ctx, get_event_type(event));
2325 add_event_to_ctx(event, ctx);
2329 perf_ctx_unlock(cpuctx, task_ctx);
2335 * Attach a performance event to a context.
2337 * Very similar to event_function_call, see comment there.
2340 perf_install_in_context(struct perf_event_context *ctx,
2341 struct perf_event *event,
2344 struct task_struct *task = READ_ONCE(ctx->task);
2346 lockdep_assert_held(&ctx->mutex);
2348 if (event->cpu != -1)
2352 * Ensures that if we can observe event->ctx, both the event and ctx
2353 * will be 'complete'. See perf_iterate_sb_cpu().
2355 smp_store_release(&event->ctx, ctx);
2358 cpu_function_call(cpu, __perf_install_in_context, event);
2363 * Should not happen, we validate the ctx is still alive before calling.
2365 if (WARN_ON_ONCE(task == TASK_TOMBSTONE))
2369 * Installing events is tricky because we cannot rely on ctx->is_active
2370 * to be set in case this is the nr_events 0 -> 1 transition.
2372 * Instead we use task_curr(), which tells us if the task is running.
2373 * However, since we use task_curr() outside of rq::lock, we can race
2374 * against the actual state. This means the result can be wrong.
2376 * If we get a false positive, we retry, this is harmless.
2378 * If we get a false negative, things are complicated. If we are after
2379 * perf_event_context_sched_in() ctx::lock will serialize us, and the
2380 * value must be correct. If we're before, it doesn't matter since
2381 * perf_event_context_sched_in() will program the counter.
2383 * However, this hinges on the remote context switch having observed
2384 * our task->perf_event_ctxp[] store, such that it will in fact take
2385 * ctx::lock in perf_event_context_sched_in().
2387 * We do this by task_function_call(), if the IPI fails to hit the task
2388 * we know any future context switch of task must see the
2389 * perf_event_ctpx[] store.
2393 * This smp_mb() orders the task->perf_event_ctxp[] store with the
2394 * task_cpu() load, such that if the IPI then does not find the task
2395 * running, a future context switch of that task must observe the
2400 if (!task_function_call(task, __perf_install_in_context, event))
2403 raw_spin_lock_irq(&ctx->lock);
2405 if (WARN_ON_ONCE(task == TASK_TOMBSTONE)) {
2407 * Cannot happen because we already checked above (which also
2408 * cannot happen), and we hold ctx->mutex, which serializes us
2409 * against perf_event_exit_task_context().
2411 raw_spin_unlock_irq(&ctx->lock);
2415 * If the task is not running, ctx->lock will avoid it becoming so,
2416 * thus we can safely install the event.
2418 if (task_curr(task)) {
2419 raw_spin_unlock_irq(&ctx->lock);
2422 add_event_to_ctx(event, ctx);
2423 raw_spin_unlock_irq(&ctx->lock);
2427 * Cross CPU call to enable a performance event
2429 static void __perf_event_enable(struct perf_event *event,
2430 struct perf_cpu_context *cpuctx,
2431 struct perf_event_context *ctx,
2434 struct perf_event *leader = event->group_leader;
2435 struct perf_event_context *task_ctx;
2437 if (event->state >= PERF_EVENT_STATE_INACTIVE ||
2438 event->state <= PERF_EVENT_STATE_ERROR)
2442 ctx_sched_out(ctx, cpuctx, EVENT_TIME);
2444 perf_event_set_state(event, PERF_EVENT_STATE_INACTIVE);
2446 if (!ctx->is_active)
2449 if (!event_filter_match(event)) {
2450 ctx_sched_in(ctx, cpuctx, EVENT_TIME, current);
2455 * If the event is in a group and isn't the group leader,
2456 * then don't put it on unless the group is on.
2458 if (leader != event && leader->state != PERF_EVENT_STATE_ACTIVE) {
2459 ctx_sched_in(ctx, cpuctx, EVENT_TIME, current);
2463 task_ctx = cpuctx->task_ctx;
2465 WARN_ON_ONCE(task_ctx != ctx);
2467 ctx_resched(cpuctx, task_ctx, get_event_type(event));
2473 * If event->ctx is a cloned context, callers must make sure that
2474 * every task struct that event->ctx->task could possibly point to
2475 * remains valid. This condition is satisfied when called through
2476 * perf_event_for_each_child or perf_event_for_each as described
2477 * for perf_event_disable.
2479 static void _perf_event_enable(struct perf_event *event)
2481 struct perf_event_context *ctx = event->ctx;
2483 raw_spin_lock_irq(&ctx->lock);
2484 if (event->state >= PERF_EVENT_STATE_INACTIVE ||
2485 event->state < PERF_EVENT_STATE_ERROR) {
2486 raw_spin_unlock_irq(&ctx->lock);
2491 * If the event is in error state, clear that first.
2493 * That way, if we see the event in error state below, we know that it
2494 * has gone back into error state, as distinct from the task having
2495 * been scheduled away before the cross-call arrived.
2497 if (event->state == PERF_EVENT_STATE_ERROR)
2498 event->state = PERF_EVENT_STATE_OFF;
2499 raw_spin_unlock_irq(&ctx->lock);
2501 event_function_call(event, __perf_event_enable, NULL);
2505 * See perf_event_disable();
2507 void perf_event_enable(struct perf_event *event)
2509 struct perf_event_context *ctx;
2511 ctx = perf_event_ctx_lock(event);
2512 _perf_event_enable(event);
2513 perf_event_ctx_unlock(event, ctx);
2515 EXPORT_SYMBOL_GPL(perf_event_enable);
2517 struct stop_event_data {
2518 struct perf_event *event;
2519 unsigned int restart;
2522 static int __perf_event_stop(void *info)
2524 struct stop_event_data *sd = info;
2525 struct perf_event *event = sd->event;
2527 /* if it's already INACTIVE, do nothing */
2528 if (READ_ONCE(event->state) != PERF_EVENT_STATE_ACTIVE)
2531 /* matches smp_wmb() in event_sched_in() */
2535 * There is a window with interrupts enabled before we get here,
2536 * so we need to check again lest we try to stop another CPU's event.
2538 if (READ_ONCE(event->oncpu) != smp_processor_id())
2541 event->pmu->stop(event, PERF_EF_UPDATE);
2544 * May race with the actual stop (through perf_pmu_output_stop()),
2545 * but it is only used for events with AUX ring buffer, and such
2546 * events will refuse to restart because of rb::aux_mmap_count==0,
2547 * see comments in perf_aux_output_begin().
2549 * Since this is happening on a event-local CPU, no trace is lost
2553 event->pmu->start(event, 0);
2558 static int perf_event_stop(struct perf_event *event, int restart)
2560 struct stop_event_data sd = {
2567 if (READ_ONCE(event->state) != PERF_EVENT_STATE_ACTIVE)
2570 /* matches smp_wmb() in event_sched_in() */
2574 * We only want to restart ACTIVE events, so if the event goes
2575 * inactive here (event->oncpu==-1), there's nothing more to do;
2576 * fall through with ret==-ENXIO.
2578 ret = cpu_function_call(READ_ONCE(event->oncpu),
2579 __perf_event_stop, &sd);
2580 } while (ret == -EAGAIN);
2586 * In order to contain the amount of racy and tricky in the address filter
2587 * configuration management, it is a two part process:
2589 * (p1) when userspace mappings change as a result of (1) or (2) or (3) below,
2590 * we update the addresses of corresponding vmas in
2591 * event::addr_filters_offs array and bump the event::addr_filters_gen;
2592 * (p2) when an event is scheduled in (pmu::add), it calls
2593 * perf_event_addr_filters_sync() which calls pmu::addr_filters_sync()
2594 * if the generation has changed since the previous call.
2596 * If (p1) happens while the event is active, we restart it to force (p2).
2598 * (1) perf_addr_filters_apply(): adjusting filters' offsets based on
2599 * pre-existing mappings, called once when new filters arrive via SET_FILTER
2601 * (2) perf_addr_filters_adjust(): adjusting filters' offsets based on newly
2602 * registered mapping, called for every new mmap(), with mm::mmap_sem down
2604 * (3) perf_event_addr_filters_exec(): clearing filters' offsets in the process
2607 void perf_event_addr_filters_sync(struct perf_event *event)
2609 struct perf_addr_filters_head *ifh = perf_event_addr_filters(event);
2611 if (!has_addr_filter(event))
2614 raw_spin_lock(&ifh->lock);
2615 if (event->addr_filters_gen != event->hw.addr_filters_gen) {
2616 event->pmu->addr_filters_sync(event);
2617 event->hw.addr_filters_gen = event->addr_filters_gen;
2619 raw_spin_unlock(&ifh->lock);
2621 EXPORT_SYMBOL_GPL(perf_event_addr_filters_sync);
2623 static int _perf_event_refresh(struct perf_event *event, int refresh)
2626 * not supported on inherited events
2628 if (event->attr.inherit || !is_sampling_event(event))
2631 atomic_add(refresh, &event->event_limit);
2632 _perf_event_enable(event);
2638 * See perf_event_disable()
2640 int perf_event_refresh(struct perf_event *event, int refresh)
2642 struct perf_event_context *ctx;
2645 ctx = perf_event_ctx_lock(event);
2646 ret = _perf_event_refresh(event, refresh);
2647 perf_event_ctx_unlock(event, ctx);
2651 EXPORT_SYMBOL_GPL(perf_event_refresh);
2653 static void ctx_sched_out(struct perf_event_context *ctx,
2654 struct perf_cpu_context *cpuctx,
2655 enum event_type_t event_type)
2657 int is_active = ctx->is_active;
2658 struct perf_event *event;
2660 lockdep_assert_held(&ctx->lock);
2662 if (likely(!ctx->nr_events)) {
2664 * See __perf_remove_from_context().
2666 WARN_ON_ONCE(ctx->is_active);
2668 WARN_ON_ONCE(cpuctx->task_ctx);
2672 ctx->is_active &= ~event_type;
2673 if (!(ctx->is_active & EVENT_ALL))
2677 WARN_ON_ONCE(cpuctx->task_ctx != ctx);
2678 if (!ctx->is_active)
2679 cpuctx->task_ctx = NULL;
2683 * Always update time if it was set; not only when it changes.
2684 * Otherwise we can 'forget' to update time for any but the last
2685 * context we sched out. For example:
2687 * ctx_sched_out(.event_type = EVENT_FLEXIBLE)
2688 * ctx_sched_out(.event_type = EVENT_PINNED)
2690 * would only update time for the pinned events.
2692 if (is_active & EVENT_TIME) {
2693 /* update (and stop) ctx time */
2694 update_context_time(ctx);
2695 update_cgrp_time_from_cpuctx(cpuctx);
2698 is_active ^= ctx->is_active; /* changed bits */
2700 if (!ctx->nr_active || !(is_active & EVENT_ALL))
2703 perf_pmu_disable(ctx->pmu);
2704 if (is_active & EVENT_PINNED) {
2705 list_for_each_entry(event, &ctx->pinned_groups, group_entry)
2706 group_sched_out(event, cpuctx, ctx);
2709 if (is_active & EVENT_FLEXIBLE) {
2710 list_for_each_entry(event, &ctx->flexible_groups, group_entry)
2711 group_sched_out(event, cpuctx, ctx);
2713 perf_pmu_enable(ctx->pmu);
2717 * Test whether two contexts are equivalent, i.e. whether they have both been
2718 * cloned from the same version of the same context.
2720 * Equivalence is measured using a generation number in the context that is
2721 * incremented on each modification to it; see unclone_ctx(), list_add_event()
2722 * and list_del_event().
2724 static int context_equiv(struct perf_event_context *ctx1,
2725 struct perf_event_context *ctx2)
2727 lockdep_assert_held(&ctx1->lock);
2728 lockdep_assert_held(&ctx2->lock);
2730 /* Pinning disables the swap optimization */
2731 if (ctx1->pin_count || ctx2->pin_count)
2734 /* If ctx1 is the parent of ctx2 */
2735 if (ctx1 == ctx2->parent_ctx && ctx1->generation == ctx2->parent_gen)
2738 /* If ctx2 is the parent of ctx1 */
2739 if (ctx1->parent_ctx == ctx2 && ctx1->parent_gen == ctx2->generation)
2743 * If ctx1 and ctx2 have the same parent; we flatten the parent
2744 * hierarchy, see perf_event_init_context().
2746 if (ctx1->parent_ctx && ctx1->parent_ctx == ctx2->parent_ctx &&
2747 ctx1->parent_gen == ctx2->parent_gen)
2754 static void __perf_event_sync_stat(struct perf_event *event,
2755 struct perf_event *next_event)
2759 if (!event->attr.inherit_stat)
2763 * Update the event value, we cannot use perf_event_read()
2764 * because we're in the middle of a context switch and have IRQs
2765 * disabled, which upsets smp_call_function_single(), however
2766 * we know the event must be on the current CPU, therefore we
2767 * don't need to use it.
2769 if (event->state == PERF_EVENT_STATE_ACTIVE)
2770 event->pmu->read(event);
2772 perf_event_update_time(event);
2775 * In order to keep per-task stats reliable we need to flip the event
2776 * values when we flip the contexts.
2778 value = local64_read(&next_event->count);
2779 value = local64_xchg(&event->count, value);
2780 local64_set(&next_event->count, value);
2782 swap(event->total_time_enabled, next_event->total_time_enabled);
2783 swap(event->total_time_running, next_event->total_time_running);
2786 * Since we swizzled the values, update the user visible data too.
2788 perf_event_update_userpage(event);
2789 perf_event_update_userpage(next_event);
2792 static void perf_event_sync_stat(struct perf_event_context *ctx,
2793 struct perf_event_context *next_ctx)
2795 struct perf_event *event, *next_event;
2800 update_context_time(ctx);
2802 event = list_first_entry(&ctx->event_list,
2803 struct perf_event, event_entry);
2805 next_event = list_first_entry(&next_ctx->event_list,
2806 struct perf_event, event_entry);
2808 while (&event->event_entry != &ctx->event_list &&
2809 &next_event->event_entry != &next_ctx->event_list) {
2811 __perf_event_sync_stat(event, next_event);
2813 event = list_next_entry(event, event_entry);
2814 next_event = list_next_entry(next_event, event_entry);
2818 static void perf_event_context_sched_out(struct task_struct *task, int ctxn,
2819 struct task_struct *next)
2821 struct perf_event_context *ctx = task->perf_event_ctxp[ctxn];
2822 struct perf_event_context *next_ctx;
2823 struct perf_event_context *parent, *next_parent;
2824 struct perf_cpu_context *cpuctx;
2830 cpuctx = __get_cpu_context(ctx);
2831 if (!cpuctx->task_ctx)
2835 next_ctx = next->perf_event_ctxp[ctxn];
2839 parent = rcu_dereference(ctx->parent_ctx);
2840 next_parent = rcu_dereference(next_ctx->parent_ctx);
2842 /* If neither context have a parent context; they cannot be clones. */
2843 if (!parent && !next_parent)
2846 if (next_parent == ctx || next_ctx == parent || next_parent == parent) {
2848 * Looks like the two contexts are clones, so we might be
2849 * able to optimize the context switch. We lock both
2850 * contexts and check that they are clones under the
2851 * lock (including re-checking that neither has been
2852 * uncloned in the meantime). It doesn't matter which
2853 * order we take the locks because no other cpu could
2854 * be trying to lock both of these tasks.
2856 raw_spin_lock(&ctx->lock);
2857 raw_spin_lock_nested(&next_ctx->lock, SINGLE_DEPTH_NESTING);
2858 if (context_equiv(ctx, next_ctx)) {
2859 WRITE_ONCE(ctx->task, next);
2860 WRITE_ONCE(next_ctx->task, task);
2862 swap(ctx->task_ctx_data, next_ctx->task_ctx_data);
2865 * RCU_INIT_POINTER here is safe because we've not
2866 * modified the ctx and the above modification of
2867 * ctx->task and ctx->task_ctx_data are immaterial
2868 * since those values are always verified under
2869 * ctx->lock which we're now holding.
2871 RCU_INIT_POINTER(task->perf_event_ctxp[ctxn], next_ctx);
2872 RCU_INIT_POINTER(next->perf_event_ctxp[ctxn], ctx);
2876 perf_event_sync_stat(ctx, next_ctx);
2878 raw_spin_unlock(&next_ctx->lock);
2879 raw_spin_unlock(&ctx->lock);
2885 raw_spin_lock(&ctx->lock);
2886 task_ctx_sched_out(cpuctx, ctx, EVENT_ALL);
2887 raw_spin_unlock(&ctx->lock);
2891 static DEFINE_PER_CPU(struct list_head, sched_cb_list);
2893 void perf_sched_cb_dec(struct pmu *pmu)
2895 struct perf_cpu_context *cpuctx = this_cpu_ptr(pmu->pmu_cpu_context);
2897 this_cpu_dec(perf_sched_cb_usages);
2899 if (!--cpuctx->sched_cb_usage)
2900 list_del(&cpuctx->sched_cb_entry);
2904 void perf_sched_cb_inc(struct pmu *pmu)
2906 struct perf_cpu_context *cpuctx = this_cpu_ptr(pmu->pmu_cpu_context);
2908 if (!cpuctx->sched_cb_usage++)
2909 list_add(&cpuctx->sched_cb_entry, this_cpu_ptr(&sched_cb_list));
2911 this_cpu_inc(perf_sched_cb_usages);
2915 * This function provides the context switch callback to the lower code
2916 * layer. It is invoked ONLY when the context switch callback is enabled.
2918 * This callback is relevant even to per-cpu events; for example multi event
2919 * PEBS requires this to provide PID/TID information. This requires we flush
2920 * all queued PEBS records before we context switch to a new task.
2922 static void perf_pmu_sched_task(struct task_struct *prev,
2923 struct task_struct *next,
2926 struct perf_cpu_context *cpuctx;
2932 list_for_each_entry(cpuctx, this_cpu_ptr(&sched_cb_list), sched_cb_entry) {
2933 pmu = cpuctx->ctx.pmu; /* software PMUs will not have sched_task */
2935 if (WARN_ON_ONCE(!pmu->sched_task))
2938 perf_ctx_lock(cpuctx, cpuctx->task_ctx);
2939 perf_pmu_disable(pmu);
2941 pmu->sched_task(cpuctx->task_ctx, sched_in);
2943 perf_pmu_enable(pmu);
2944 perf_ctx_unlock(cpuctx, cpuctx->task_ctx);
2948 static void perf_event_switch(struct task_struct *task,
2949 struct task_struct *next_prev, bool sched_in);
2951 #define for_each_task_context_nr(ctxn) \
2952 for ((ctxn) = 0; (ctxn) < perf_nr_task_contexts; (ctxn)++)
2955 * Called from scheduler to remove the events of the current task,
2956 * with interrupts disabled.
2958 * We stop each event and update the event value in event->count.
2960 * This does not protect us against NMI, but disable()
2961 * sets the disabled bit in the control field of event _before_
2962 * accessing the event control register. If a NMI hits, then it will
2963 * not restart the event.
2965 void __perf_event_task_sched_out(struct task_struct *task,
2966 struct task_struct *next)
2970 if (__this_cpu_read(perf_sched_cb_usages))
2971 perf_pmu_sched_task(task, next, false);
2973 if (atomic_read(&nr_switch_events))
2974 perf_event_switch(task, next, false);
2976 for_each_task_context_nr(ctxn)
2977 perf_event_context_sched_out(task, ctxn, next);
2980 * if cgroup events exist on this CPU, then we need
2981 * to check if we have to switch out PMU state.
2982 * cgroup event are system-wide mode only
2984 if (atomic_read(this_cpu_ptr(&perf_cgroup_events)))
2985 perf_cgroup_sched_out(task, next);
2989 * Called with IRQs disabled
2991 static void cpu_ctx_sched_out(struct perf_cpu_context *cpuctx,
2992 enum event_type_t event_type)
2994 ctx_sched_out(&cpuctx->ctx, cpuctx, event_type);
2998 ctx_pinned_sched_in(struct perf_event_context *ctx,
2999 struct perf_cpu_context *cpuctx)
3001 struct perf_event *event;
3003 list_for_each_entry(event, &ctx->pinned_groups, group_entry) {
3004 if (event->state <= PERF_EVENT_STATE_OFF)
3006 if (!event_filter_match(event))
3009 if (group_can_go_on(event, cpuctx, 1))
3010 group_sched_in(event, cpuctx, ctx);
3013 * If this pinned group hasn't been scheduled,
3014 * put it in error state.
3016 if (event->state == PERF_EVENT_STATE_INACTIVE)
3017 perf_event_set_state(event, PERF_EVENT_STATE_ERROR);
3022 ctx_flexible_sched_in(struct perf_event_context *ctx,
3023 struct perf_cpu_context *cpuctx)
3025 struct perf_event *event;
3028 list_for_each_entry(event, &ctx->flexible_groups, group_entry) {
3029 /* Ignore events in OFF or ERROR state */
3030 if (event->state <= PERF_EVENT_STATE_OFF)
3033 * Listen to the 'cpu' scheduling filter constraint
3036 if (!event_filter_match(event))
3039 if (group_can_go_on(event, cpuctx, can_add_hw)) {
3040 if (group_sched_in(event, cpuctx, ctx))
3047 ctx_sched_in(struct perf_event_context *ctx,
3048 struct perf_cpu_context *cpuctx,
3049 enum event_type_t event_type,
3050 struct task_struct *task)
3052 int is_active = ctx->is_active;
3055 lockdep_assert_held(&ctx->lock);
3057 if (likely(!ctx->nr_events))
3060 ctx->is_active |= (event_type | EVENT_TIME);
3063 cpuctx->task_ctx = ctx;
3065 WARN_ON_ONCE(cpuctx->task_ctx != ctx);
3068 is_active ^= ctx->is_active; /* changed bits */
3070 if (is_active & EVENT_TIME) {
3071 /* start ctx time */
3073 ctx->timestamp = now;
3074 perf_cgroup_set_timestamp(task, ctx);
3078 * First go through the list and put on any pinned groups
3079 * in order to give them the best chance of going on.
3081 if (is_active & EVENT_PINNED)
3082 ctx_pinned_sched_in(ctx, cpuctx);
3084 /* Then walk through the lower prio flexible groups */
3085 if (is_active & EVENT_FLEXIBLE)
3086 ctx_flexible_sched_in(ctx, cpuctx);
3089 static void cpu_ctx_sched_in(struct perf_cpu_context *cpuctx,
3090 enum event_type_t event_type,
3091 struct task_struct *task)
3093 struct perf_event_context *ctx = &cpuctx->ctx;
3095 ctx_sched_in(ctx, cpuctx, event_type, task);
3098 static void perf_event_context_sched_in(struct perf_event_context *ctx,
3099 struct task_struct *task)
3101 struct perf_cpu_context *cpuctx;
3103 cpuctx = __get_cpu_context(ctx);
3104 if (cpuctx->task_ctx == ctx)
3107 perf_ctx_lock(cpuctx, ctx);
3109 * We must check ctx->nr_events while holding ctx->lock, such
3110 * that we serialize against perf_install_in_context().
3112 if (!ctx->nr_events)
3115 perf_pmu_disable(ctx->pmu);
3117 * We want to keep the following priority order:
3118 * cpu pinned (that don't need to move), task pinned,
3119 * cpu flexible, task flexible.
3121 * However, if task's ctx is not carrying any pinned
3122 * events, no need to flip the cpuctx's events around.
3124 if (!list_empty(&ctx->pinned_groups))
3125 cpu_ctx_sched_out(cpuctx, EVENT_FLEXIBLE);
3126 perf_event_sched_in(cpuctx, ctx, task);
3127 perf_pmu_enable(ctx->pmu);
3130 perf_ctx_unlock(cpuctx, ctx);
3134 * Called from scheduler to add the events of the current task
3135 * with interrupts disabled.
3137 * We restore the event value and then enable it.
3139 * This does not protect us against NMI, but enable()
3140 * sets the enabled bit in the control field of event _before_
3141 * accessing the event control register. If a NMI hits, then it will
3142 * keep the event running.
3144 void __perf_event_task_sched_in(struct task_struct *prev,
3145 struct task_struct *task)
3147 struct perf_event_context *ctx;
3151 * If cgroup events exist on this CPU, then we need to check if we have
3152 * to switch in PMU state; cgroup event are system-wide mode only.
3154 * Since cgroup events are CPU events, we must schedule these in before
3155 * we schedule in the task events.
3157 if (atomic_read(this_cpu_ptr(&perf_cgroup_events)))
3158 perf_cgroup_sched_in(prev, task);
3160 for_each_task_context_nr(ctxn) {
3161 ctx = task->perf_event_ctxp[ctxn];
3165 perf_event_context_sched_in(ctx, task);
3168 if (atomic_read(&nr_switch_events))
3169 perf_event_switch(task, prev, true);
3171 if (__this_cpu_read(perf_sched_cb_usages))
3172 perf_pmu_sched_task(prev, task, true);
3175 static u64 perf_calculate_period(struct perf_event *event, u64 nsec, u64 count)
3177 u64 frequency = event->attr.sample_freq;
3178 u64 sec = NSEC_PER_SEC;
3179 u64 divisor, dividend;
3181 int count_fls, nsec_fls, frequency_fls, sec_fls;
3183 count_fls = fls64(count);
3184 nsec_fls = fls64(nsec);
3185 frequency_fls = fls64(frequency);
3189 * We got @count in @nsec, with a target of sample_freq HZ
3190 * the target period becomes:
3193 * period = -------------------
3194 * @nsec * sample_freq
3199 * Reduce accuracy by one bit such that @a and @b converge
3200 * to a similar magnitude.
3202 #define REDUCE_FLS(a, b) \
3204 if (a##_fls > b##_fls) { \
3214 * Reduce accuracy until either term fits in a u64, then proceed with
3215 * the other, so that finally we can do a u64/u64 division.
3217 while (count_fls + sec_fls > 64 && nsec_fls + frequency_fls > 64) {
3218 REDUCE_FLS(nsec, frequency);
3219 REDUCE_FLS(sec, count);
3222 if (count_fls + sec_fls > 64) {
3223 divisor = nsec * frequency;
3225 while (count_fls + sec_fls > 64) {
3226 REDUCE_FLS(count, sec);
3230 dividend = count * sec;
3232 dividend = count * sec;
3234 while (nsec_fls + frequency_fls > 64) {
3235 REDUCE_FLS(nsec, frequency);
3239 divisor = nsec * frequency;
3245 return div64_u64(dividend, divisor);
3248 static DEFINE_PER_CPU(int, perf_throttled_count);
3249 static DEFINE_PER_CPU(u64, perf_throttled_seq);
3251 static void perf_adjust_period(struct perf_event *event, u64 nsec, u64 count, bool disable)
3253 struct hw_perf_event *hwc = &event->hw;
3254 s64 period, sample_period;
3257 period = perf_calculate_period(event, nsec, count);
3259 delta = (s64)(period - hwc->sample_period);
3260 delta = (delta + 7) / 8; /* low pass filter */
3262 sample_period = hwc->sample_period + delta;
3267 hwc->sample_period = sample_period;
3269 if (local64_read(&hwc->period_left) > 8*sample_period) {
3271 event->pmu->stop(event, PERF_EF_UPDATE);
3273 local64_set(&hwc->period_left, 0);
3276 event->pmu->start(event, PERF_EF_RELOAD);
3281 * combine freq adjustment with unthrottling to avoid two passes over the
3282 * events. At the same time, make sure, having freq events does not change
3283 * the rate of unthrottling as that would introduce bias.
3285 static void perf_adjust_freq_unthr_context(struct perf_event_context *ctx,
3288 struct perf_event *event;
3289 struct hw_perf_event *hwc;
3290 u64 now, period = TICK_NSEC;
3294 * only need to iterate over all events iff:
3295 * - context have events in frequency mode (needs freq adjust)
3296 * - there are events to unthrottle on this cpu
3298 if (!(ctx->nr_freq || needs_unthr))
3301 raw_spin_lock(&ctx->lock);
3302 perf_pmu_disable(ctx->pmu);
3304 list_for_each_entry_rcu(event, &ctx->event_list, event_entry) {
3305 if (event->state != PERF_EVENT_STATE_ACTIVE)
3308 if (!event_filter_match(event))
3311 perf_pmu_disable(event->pmu);
3315 if (hwc->interrupts == MAX_INTERRUPTS) {
3316 hwc->interrupts = 0;
3317 perf_log_throttle(event, 1);
3318 event->pmu->start(event, 0);
3321 if (!event->attr.freq || !event->attr.sample_freq)
3325 * stop the event and update event->count
3327 event->pmu->stop(event, PERF_EF_UPDATE);
3329 now = local64_read(&event->count);
3330 delta = now - hwc->freq_count_stamp;
3331 hwc->freq_count_stamp = now;
3335 * reload only if value has changed
3336 * we have stopped the event so tell that
3337 * to perf_adjust_period() to avoid stopping it
3341 perf_adjust_period(event, period, delta, false);
3343 event->pmu->start(event, delta > 0 ? PERF_EF_RELOAD : 0);
3345 perf_pmu_enable(event->pmu);
3348 perf_pmu_enable(ctx->pmu);
3349 raw_spin_unlock(&ctx->lock);
3353 * Round-robin a context's events:
3355 static void rotate_ctx(struct perf_event_context *ctx)
3358 * Rotate the first entry last of non-pinned groups. Rotation might be
3359 * disabled by the inheritance code.
3361 if (!ctx->rotate_disable)
3362 list_rotate_left(&ctx->flexible_groups);
3365 static int perf_rotate_context(struct perf_cpu_context *cpuctx)
3367 struct perf_event_context *ctx = NULL;
3370 if (cpuctx->ctx.nr_events) {
3371 if (cpuctx->ctx.nr_events != cpuctx->ctx.nr_active)
3375 ctx = cpuctx->task_ctx;
3376 if (ctx && ctx->nr_events) {
3377 if (ctx->nr_events != ctx->nr_active)
3384 perf_ctx_lock(cpuctx, cpuctx->task_ctx);
3385 perf_pmu_disable(cpuctx->ctx.pmu);
3387 cpu_ctx_sched_out(cpuctx, EVENT_FLEXIBLE);
3389 ctx_sched_out(ctx, cpuctx, EVENT_FLEXIBLE);
3391 rotate_ctx(&cpuctx->ctx);
3395 perf_event_sched_in(cpuctx, ctx, current);
3397 perf_pmu_enable(cpuctx->ctx.pmu);
3398 perf_ctx_unlock(cpuctx, cpuctx->task_ctx);
3404 void perf_event_task_tick(void)
3406 struct list_head *head = this_cpu_ptr(&active_ctx_list);
3407 struct perf_event_context *ctx, *tmp;
3410 lockdep_assert_irqs_disabled();
3412 __this_cpu_inc(perf_throttled_seq);
3413 throttled = __this_cpu_xchg(perf_throttled_count, 0);
3414 tick_dep_clear_cpu(smp_processor_id(), TICK_DEP_BIT_PERF_EVENTS);
3416 list_for_each_entry_safe(ctx, tmp, head, active_ctx_list)
3417 perf_adjust_freq_unthr_context(ctx, throttled);
3420 static int event_enable_on_exec(struct perf_event *event,
3421 struct perf_event_context *ctx)
3423 if (!event->attr.enable_on_exec)
3426 event->attr.enable_on_exec = 0;
3427 if (event->state >= PERF_EVENT_STATE_INACTIVE)
3430 perf_event_set_state(event, PERF_EVENT_STATE_INACTIVE);
3436 * Enable all of a task's events that have been marked enable-on-exec.
3437 * This expects task == current.
3439 static void perf_event_enable_on_exec(int ctxn)
3441 struct perf_event_context *ctx, *clone_ctx = NULL;
3442 enum event_type_t event_type = 0;
3443 struct perf_cpu_context *cpuctx;
3444 struct perf_event *event;
3445 unsigned long flags;
3448 local_irq_save(flags);
3449 ctx = current->perf_event_ctxp[ctxn];
3450 if (!ctx || !ctx->nr_events)
3453 cpuctx = __get_cpu_context(ctx);
3454 perf_ctx_lock(cpuctx, ctx);
3455 ctx_sched_out(ctx, cpuctx, EVENT_TIME);
3456 list_for_each_entry(event, &ctx->event_list, event_entry) {
3457 enabled |= event_enable_on_exec(event, ctx);
3458 event_type |= get_event_type(event);
3462 * Unclone and reschedule this context if we enabled any event.
3465 clone_ctx = unclone_ctx(ctx);
3466 ctx_resched(cpuctx, ctx, event_type);
3468 ctx_sched_in(ctx, cpuctx, EVENT_TIME, current);
3470 perf_ctx_unlock(cpuctx, ctx);
3473 local_irq_restore(flags);
3479 struct perf_read_data {
3480 struct perf_event *event;
3485 static int __perf_event_read_cpu(struct perf_event *event, int event_cpu)
3487 u16 local_pkg, event_pkg;
3489 if (event->group_caps & PERF_EV_CAP_READ_ACTIVE_PKG) {
3490 int local_cpu = smp_processor_id();
3492 event_pkg = topology_physical_package_id(event_cpu);
3493 local_pkg = topology_physical_package_id(local_cpu);
3495 if (event_pkg == local_pkg)
3503 * Cross CPU call to read the hardware event
3505 static void __perf_event_read(void *info)
3507 struct perf_read_data *data = info;
3508 struct perf_event *sub, *event = data->event;
3509 struct perf_event_context *ctx = event->ctx;
3510 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
3511 struct pmu *pmu = event->pmu;
3514 * If this is a task context, we need to check whether it is
3515 * the current task context of this cpu. If not it has been
3516 * scheduled out before the smp call arrived. In that case
3517 * event->count would have been updated to a recent sample
3518 * when the event was scheduled out.
3520 if (ctx->task && cpuctx->task_ctx != ctx)
3523 raw_spin_lock(&ctx->lock);
3524 if (ctx->is_active & EVENT_TIME) {
3525 update_context_time(ctx);
3526 update_cgrp_time_from_event(event);
3529 perf_event_update_time(event);
3531 perf_event_update_sibling_time(event);
3533 if (event->state != PERF_EVENT_STATE_ACTIVE)
3542 pmu->start_txn(pmu, PERF_PMU_TXN_READ);
3546 list_for_each_entry(sub, &event->sibling_list, group_entry) {
3547 if (sub->state == PERF_EVENT_STATE_ACTIVE) {
3549 * Use sibling's PMU rather than @event's since
3550 * sibling could be on different (eg: software) PMU.
3552 sub->pmu->read(sub);
3556 data->ret = pmu->commit_txn(pmu);
3559 raw_spin_unlock(&ctx->lock);
3562 static inline u64 perf_event_count(struct perf_event *event)
3564 return local64_read(&event->count) + atomic64_read(&event->child_count);
3568 * NMI-safe method to read a local event, that is an event that
3570 * - either for the current task, or for this CPU
3571 * - does not have inherit set, for inherited task events
3572 * will not be local and we cannot read them atomically
3573 * - must not have a pmu::count method
3575 int perf_event_read_local(struct perf_event *event, u64 *value,
3576 u64 *enabled, u64 *running)
3578 unsigned long flags;
3582 * Disabling interrupts avoids all counter scheduling (context
3583 * switches, timer based rotation and IPIs).
3585 local_irq_save(flags);
3588 * It must not be an event with inherit set, we cannot read
3589 * all child counters from atomic context.
3591 if (event->attr.inherit) {
3596 /* If this is a per-task event, it must be for current */
3597 if ((event->attach_state & PERF_ATTACH_TASK) &&
3598 event->hw.target != current) {
3603 /* If this is a per-CPU event, it must be for this CPU */
3604 if (!(event->attach_state & PERF_ATTACH_TASK) &&
3605 event->cpu != smp_processor_id()) {
3611 * If the event is currently on this CPU, its either a per-task event,
3612 * or local to this CPU. Furthermore it means its ACTIVE (otherwise
3615 if (event->oncpu == smp_processor_id())
3616 event->pmu->read(event);
3618 *value = local64_read(&event->count);
3619 if (enabled || running) {
3620 u64 now = event->shadow_ctx_time + perf_clock();
3621 u64 __enabled, __running;
3623 __perf_update_times(event, now, &__enabled, &__running);
3625 *enabled = __enabled;
3627 *running = __running;
3630 local_irq_restore(flags);
3635 static int perf_event_read(struct perf_event *event, bool group)
3637 enum perf_event_state state = READ_ONCE(event->state);
3638 int event_cpu, ret = 0;
3641 * If event is enabled and currently active on a CPU, update the
3642 * value in the event structure:
3645 if (state == PERF_EVENT_STATE_ACTIVE) {
3646 struct perf_read_data data;
3649 * Orders the ->state and ->oncpu loads such that if we see
3650 * ACTIVE we must also see the right ->oncpu.
3652 * Matches the smp_wmb() from event_sched_in().
3656 event_cpu = READ_ONCE(event->oncpu);
3657 if ((unsigned)event_cpu >= nr_cpu_ids)
3660 data = (struct perf_read_data){
3667 event_cpu = __perf_event_read_cpu(event, event_cpu);
3670 * Purposely ignore the smp_call_function_single() return
3673 * If event_cpu isn't a valid CPU it means the event got
3674 * scheduled out and that will have updated the event count.
3676 * Therefore, either way, we'll have an up-to-date event count
3679 (void)smp_call_function_single(event_cpu, __perf_event_read, &data, 1);
3683 } else if (state == PERF_EVENT_STATE_INACTIVE) {
3684 struct perf_event_context *ctx = event->ctx;
3685 unsigned long flags;
3687 raw_spin_lock_irqsave(&ctx->lock, flags);
3688 state = event->state;
3689 if (state != PERF_EVENT_STATE_INACTIVE) {
3690 raw_spin_unlock_irqrestore(&ctx->lock, flags);
3695 * May read while context is not active (e.g., thread is
3696 * blocked), in that case we cannot update context time
3698 if (ctx->is_active & EVENT_TIME) {
3699 update_context_time(ctx);
3700 update_cgrp_time_from_event(event);
3703 perf_event_update_time(event);
3705 perf_event_update_sibling_time(event);
3706 raw_spin_unlock_irqrestore(&ctx->lock, flags);
3713 * Initialize the perf_event context in a task_struct:
3715 static void __perf_event_init_context(struct perf_event_context *ctx)
3717 raw_spin_lock_init(&ctx->lock);
3718 mutex_init(&ctx->mutex);
3719 INIT_LIST_HEAD(&ctx->active_ctx_list);
3720 INIT_LIST_HEAD(&ctx->pinned_groups);
3721 INIT_LIST_HEAD(&ctx->flexible_groups);
3722 INIT_LIST_HEAD(&ctx->event_list);
3723 atomic_set(&ctx->refcount, 1);
3726 static struct perf_event_context *
3727 alloc_perf_context(struct pmu *pmu, struct task_struct *task)
3729 struct perf_event_context *ctx;
3731 ctx = kzalloc(sizeof(struct perf_event_context), GFP_KERNEL);
3735 __perf_event_init_context(ctx);
3738 get_task_struct(task);
3745 static struct task_struct *
3746 find_lively_task_by_vpid(pid_t vpid)
3748 struct task_struct *task;
3754 task = find_task_by_vpid(vpid);
3756 get_task_struct(task);
3760 return ERR_PTR(-ESRCH);
3766 * Returns a matching context with refcount and pincount.
3768 static struct perf_event_context *
3769 find_get_context(struct pmu *pmu, struct task_struct *task,
3770 struct perf_event *event)
3772 struct perf_event_context *ctx, *clone_ctx = NULL;
3773 struct perf_cpu_context *cpuctx;
3774 void *task_ctx_data = NULL;
3775 unsigned long flags;
3777 int cpu = event->cpu;
3780 /* Must be root to operate on a CPU event: */
3781 if (perf_paranoid_cpu() && !capable(CAP_SYS_ADMIN))
3782 return ERR_PTR(-EACCES);
3784 cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
3793 ctxn = pmu->task_ctx_nr;
3797 if (event->attach_state & PERF_ATTACH_TASK_DATA) {
3798 task_ctx_data = kzalloc(pmu->task_ctx_size, GFP_KERNEL);
3799 if (!task_ctx_data) {
3806 ctx = perf_lock_task_context(task, ctxn, &flags);
3808 clone_ctx = unclone_ctx(ctx);
3811 if (task_ctx_data && !ctx->task_ctx_data) {
3812 ctx->task_ctx_data = task_ctx_data;
3813 task_ctx_data = NULL;
3815 raw_spin_unlock_irqrestore(&ctx->lock, flags);
3820 ctx = alloc_perf_context(pmu, task);
3825 if (task_ctx_data) {
3826 ctx->task_ctx_data = task_ctx_data;
3827 task_ctx_data = NULL;
3831 mutex_lock(&task->perf_event_mutex);
3833 * If it has already passed perf_event_exit_task().
3834 * we must see PF_EXITING, it takes this mutex too.
3836 if (task->flags & PF_EXITING)
3838 else if (task->perf_event_ctxp[ctxn])
3843 rcu_assign_pointer(task->perf_event_ctxp[ctxn], ctx);
3845 mutex_unlock(&task->perf_event_mutex);
3847 if (unlikely(err)) {
3856 kfree(task_ctx_data);
3860 kfree(task_ctx_data);
3861 return ERR_PTR(err);
3864 static void perf_event_free_filter(struct perf_event *event);
3865 static void perf_event_free_bpf_prog(struct perf_event *event);
3867 static void free_event_rcu(struct rcu_head *head)
3869 struct perf_event *event;
3871 event = container_of(head, struct perf_event, rcu_head);
3873 put_pid_ns(event->ns);
3874 perf_event_free_filter(event);
3878 static void ring_buffer_attach(struct perf_event *event,
3879 struct ring_buffer *rb);
3881 static void detach_sb_event(struct perf_event *event)
3883 struct pmu_event_list *pel = per_cpu_ptr(&pmu_sb_events, event->cpu);
3885 raw_spin_lock(&pel->lock);
3886 list_del_rcu(&event->sb_list);
3887 raw_spin_unlock(&pel->lock);
3890 static bool is_sb_event(struct perf_event *event)
3892 struct perf_event_attr *attr = &event->attr;
3897 if (event->attach_state & PERF_ATTACH_TASK)
3900 if (attr->mmap || attr->mmap_data || attr->mmap2 ||
3901 attr->comm || attr->comm_exec ||
3903 attr->context_switch)
3908 static void unaccount_pmu_sb_event(struct perf_event *event)
3910 if (is_sb_event(event))
3911 detach_sb_event(event);
3914 static void unaccount_event_cpu(struct perf_event *event, int cpu)
3919 if (is_cgroup_event(event))
3920 atomic_dec(&per_cpu(perf_cgroup_events, cpu));
3923 #ifdef CONFIG_NO_HZ_FULL
3924 static DEFINE_SPINLOCK(nr_freq_lock);
3927 static void unaccount_freq_event_nohz(void)
3929 #ifdef CONFIG_NO_HZ_FULL
3930 spin_lock(&nr_freq_lock);
3931 if (atomic_dec_and_test(&nr_freq_events))
3932 tick_nohz_dep_clear(TICK_DEP_BIT_PERF_EVENTS);
3933 spin_unlock(&nr_freq_lock);
3937 static void unaccount_freq_event(void)
3939 if (tick_nohz_full_enabled())
3940 unaccount_freq_event_nohz();
3942 atomic_dec(&nr_freq_events);
3945 static void unaccount_event(struct perf_event *event)
3952 if (event->attach_state & PERF_ATTACH_TASK)
3954 if (event->attr.mmap || event->attr.mmap_data)
3955 atomic_dec(&nr_mmap_events);
3956 if (event->attr.comm)
3957 atomic_dec(&nr_comm_events);
3958 if (event->attr.namespaces)
3959 atomic_dec(&nr_namespaces_events);
3960 if (event->attr.task)
3961 atomic_dec(&nr_task_events);
3962 if (event->attr.freq)
3963 unaccount_freq_event();
3964 if (event->attr.context_switch) {
3966 atomic_dec(&nr_switch_events);
3968 if (is_cgroup_event(event))
3970 if (has_branch_stack(event))
3974 if (!atomic_add_unless(&perf_sched_count, -1, 1))
3975 schedule_delayed_work(&perf_sched_work, HZ);
3978 unaccount_event_cpu(event, event->cpu);
3980 unaccount_pmu_sb_event(event);
3983 static void perf_sched_delayed(struct work_struct *work)
3985 mutex_lock(&perf_sched_mutex);
3986 if (atomic_dec_and_test(&perf_sched_count))
3987 static_branch_disable(&perf_sched_events);
3988 mutex_unlock(&perf_sched_mutex);
3992 * The following implement mutual exclusion of events on "exclusive" pmus
3993 * (PERF_PMU_CAP_EXCLUSIVE). Such pmus can only have one event scheduled
3994 * at a time, so we disallow creating events that might conflict, namely:
3996 * 1) cpu-wide events in the presence of per-task events,
3997 * 2) per-task events in the presence of cpu-wide events,
3998 * 3) two matching events on the same context.
4000 * The former two cases are handled in the allocation path (perf_event_alloc(),
4001 * _free_event()), the latter -- before the first perf_install_in_context().
4003 static int exclusive_event_init(struct perf_event *event)
4005 struct pmu *pmu = event->pmu;
4007 if (!(pmu->capabilities & PERF_PMU_CAP_EXCLUSIVE))
4011 * Prevent co-existence of per-task and cpu-wide events on the
4012 * same exclusive pmu.
4014 * Negative pmu::exclusive_cnt means there are cpu-wide
4015 * events on this "exclusive" pmu, positive means there are
4018 * Since this is called in perf_event_alloc() path, event::ctx
4019 * doesn't exist yet; it is, however, safe to use PERF_ATTACH_TASK
4020 * to mean "per-task event", because unlike other attach states it
4021 * never gets cleared.
4023 if (event->attach_state & PERF_ATTACH_TASK) {
4024 if (!atomic_inc_unless_negative(&pmu->exclusive_cnt))
4027 if (!atomic_dec_unless_positive(&pmu->exclusive_cnt))
4034 static void exclusive_event_destroy(struct perf_event *event)
4036 struct pmu *pmu = event->pmu;
4038 if (!(pmu->capabilities & PERF_PMU_CAP_EXCLUSIVE))
4041 /* see comment in exclusive_event_init() */
4042 if (event->attach_state & PERF_ATTACH_TASK)
4043 atomic_dec(&pmu->exclusive_cnt);
4045 atomic_inc(&pmu->exclusive_cnt);
4048 static bool exclusive_event_match(struct perf_event *e1, struct perf_event *e2)
4050 if ((e1->pmu == e2->pmu) &&
4051 (e1->cpu == e2->cpu ||
4058 /* Called under the same ctx::mutex as perf_install_in_context() */
4059 static bool exclusive_event_installable(struct perf_event *event,
4060 struct perf_event_context *ctx)
4062 struct perf_event *iter_event;
4063 struct pmu *pmu = event->pmu;
4065 if (!(pmu->capabilities & PERF_PMU_CAP_EXCLUSIVE))
4068 list_for_each_entry(iter_event, &ctx->event_list, event_entry) {
4069 if (exclusive_event_match(iter_event, event))
4076 static void perf_addr_filters_splice(struct perf_event *event,
4077 struct list_head *head);
4079 static void _free_event(struct perf_event *event)
4081 irq_work_sync(&event->pending);
4083 unaccount_event(event);
4087 * Can happen when we close an event with re-directed output.
4089 * Since we have a 0 refcount, perf_mmap_close() will skip
4090 * over us; possibly making our ring_buffer_put() the last.
4092 mutex_lock(&event->mmap_mutex);
4093 ring_buffer_attach(event, NULL);
4094 mutex_unlock(&event->mmap_mutex);
4097 if (is_cgroup_event(event))
4098 perf_detach_cgroup(event);
4100 if (!event->parent) {
4101 if (event->attr.sample_type & PERF_SAMPLE_CALLCHAIN)
4102 put_callchain_buffers();
4105 perf_event_free_bpf_prog(event);
4106 perf_addr_filters_splice(event, NULL);
4107 kfree(event->addr_filters_offs);
4110 event->destroy(event);
4113 put_ctx(event->ctx);
4115 exclusive_event_destroy(event);
4116 module_put(event->pmu->module);
4118 call_rcu(&event->rcu_head, free_event_rcu);
4122 * Used to free events which have a known refcount of 1, such as in error paths
4123 * where the event isn't exposed yet and inherited events.
4125 static void free_event(struct perf_event *event)
4127 if (WARN(atomic_long_cmpxchg(&event->refcount, 1, 0) != 1,
4128 "unexpected event refcount: %ld; ptr=%p\n",
4129 atomic_long_read(&event->refcount), event)) {
4130 /* leak to avoid use-after-free */
4138 * Remove user event from the owner task.
4140 static void perf_remove_from_owner(struct perf_event *event)
4142 struct task_struct *owner;
4146 * Matches the smp_store_release() in perf_event_exit_task(). If we
4147 * observe !owner it means the list deletion is complete and we can
4148 * indeed free this event, otherwise we need to serialize on
4149 * owner->perf_event_mutex.
4151 owner = READ_ONCE(event->owner);
4154 * Since delayed_put_task_struct() also drops the last
4155 * task reference we can safely take a new reference
4156 * while holding the rcu_read_lock().
4158 get_task_struct(owner);
4164 * If we're here through perf_event_exit_task() we're already
4165 * holding ctx->mutex which would be an inversion wrt. the
4166 * normal lock order.
4168 * However we can safely take this lock because its the child
4171 mutex_lock_nested(&owner->perf_event_mutex, SINGLE_DEPTH_NESTING);
4174 * We have to re-check the event->owner field, if it is cleared
4175 * we raced with perf_event_exit_task(), acquiring the mutex
4176 * ensured they're done, and we can proceed with freeing the
4180 list_del_init(&event->owner_entry);
4181 smp_store_release(&event->owner, NULL);
4183 mutex_unlock(&owner->perf_event_mutex);
4184 put_task_struct(owner);
4188 static void put_event(struct perf_event *event)
4190 if (!atomic_long_dec_and_test(&event->refcount))
4197 * Kill an event dead; while event:refcount will preserve the event
4198 * object, it will not preserve its functionality. Once the last 'user'
4199 * gives up the object, we'll destroy the thing.
4201 int perf_event_release_kernel(struct perf_event *event)
4203 struct perf_event_context *ctx = event->ctx;
4204 struct perf_event *child, *tmp;
4205 LIST_HEAD(free_list);
4208 * If we got here through err_file: fput(event_file); we will not have
4209 * attached to a context yet.
4212 WARN_ON_ONCE(event->attach_state &
4213 (PERF_ATTACH_CONTEXT|PERF_ATTACH_GROUP));
4217 if (!is_kernel_event(event))
4218 perf_remove_from_owner(event);
4220 ctx = perf_event_ctx_lock(event);
4221 WARN_ON_ONCE(ctx->parent_ctx);
4222 perf_remove_from_context(event, DETACH_GROUP);
4224 raw_spin_lock_irq(&ctx->lock);
4226 * Mark this event as STATE_DEAD, there is no external reference to it
4229 * Anybody acquiring event->child_mutex after the below loop _must_
4230 * also see this, most importantly inherit_event() which will avoid
4231 * placing more children on the list.
4233 * Thus this guarantees that we will in fact observe and kill _ALL_
4236 event->state = PERF_EVENT_STATE_DEAD;
4237 raw_spin_unlock_irq(&ctx->lock);
4239 perf_event_ctx_unlock(event, ctx);
4242 mutex_lock(&event->child_mutex);
4243 list_for_each_entry(child, &event->child_list, child_list) {
4246 * Cannot change, child events are not migrated, see the
4247 * comment with perf_event_ctx_lock_nested().
4249 ctx = READ_ONCE(child->ctx);
4251 * Since child_mutex nests inside ctx::mutex, we must jump
4252 * through hoops. We start by grabbing a reference on the ctx.
4254 * Since the event cannot get freed while we hold the
4255 * child_mutex, the context must also exist and have a !0
4261 * Now that we have a ctx ref, we can drop child_mutex, and
4262 * acquire ctx::mutex without fear of it going away. Then we
4263 * can re-acquire child_mutex.
4265 mutex_unlock(&event->child_mutex);
4266 mutex_lock(&ctx->mutex);
4267 mutex_lock(&event->child_mutex);
4270 * Now that we hold ctx::mutex and child_mutex, revalidate our
4271 * state, if child is still the first entry, it didn't get freed
4272 * and we can continue doing so.
4274 tmp = list_first_entry_or_null(&event->child_list,
4275 struct perf_event, child_list);
4277 perf_remove_from_context(child, DETACH_GROUP);
4278 list_move(&child->child_list, &free_list);
4280 * This matches the refcount bump in inherit_event();
4281 * this can't be the last reference.
4286 mutex_unlock(&event->child_mutex);
4287 mutex_unlock(&ctx->mutex);
4291 mutex_unlock(&event->child_mutex);
4293 list_for_each_entry_safe(child, tmp, &free_list, child_list) {
4294 list_del(&child->child_list);
4299 put_event(event); /* Must be the 'last' reference */
4302 EXPORT_SYMBOL_GPL(perf_event_release_kernel);
4305 * Called when the last reference to the file is gone.
4307 static int perf_release(struct inode *inode, struct file *file)
4309 perf_event_release_kernel(file->private_data);
4313 static u64 __perf_event_read_value(struct perf_event *event, u64 *enabled, u64 *running)
4315 struct perf_event *child;
4321 mutex_lock(&event->child_mutex);
4323 (void)perf_event_read(event, false);
4324 total += perf_event_count(event);
4326 *enabled += event->total_time_enabled +
4327 atomic64_read(&event->child_total_time_enabled);
4328 *running += event->total_time_running +
4329 atomic64_read(&event->child_total_time_running);
4331 list_for_each_entry(child, &event->child_list, child_list) {
4332 (void)perf_event_read(child, false);
4333 total += perf_event_count(child);
4334 *enabled += child->total_time_enabled;
4335 *running += child->total_time_running;
4337 mutex_unlock(&event->child_mutex);
4342 u64 perf_event_read_value(struct perf_event *event, u64 *enabled, u64 *running)
4344 struct perf_event_context *ctx;
4347 ctx = perf_event_ctx_lock(event);
4348 count = __perf_event_read_value(event, enabled, running);
4349 perf_event_ctx_unlock(event, ctx);
4353 EXPORT_SYMBOL_GPL(perf_event_read_value);
4355 static int __perf_read_group_add(struct perf_event *leader,
4356 u64 read_format, u64 *values)
4358 struct perf_event_context *ctx = leader->ctx;
4359 struct perf_event *sub;
4360 unsigned long flags;
4361 int n = 1; /* skip @nr */
4364 ret = perf_event_read(leader, true);
4368 raw_spin_lock_irqsave(&ctx->lock, flags);
4371 * Since we co-schedule groups, {enabled,running} times of siblings
4372 * will be identical to those of the leader, so we only publish one
4375 if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED) {
4376 values[n++] += leader->total_time_enabled +
4377 atomic64_read(&leader->child_total_time_enabled);
4380 if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING) {
4381 values[n++] += leader->total_time_running +
4382 atomic64_read(&leader->child_total_time_running);
4386 * Write {count,id} tuples for every sibling.
4388 values[n++] += perf_event_count(leader);
4389 if (read_format & PERF_FORMAT_ID)
4390 values[n++] = primary_event_id(leader);
4392 list_for_each_entry(sub, &leader->sibling_list, group_entry) {
4393 values[n++] += perf_event_count(sub);
4394 if (read_format & PERF_FORMAT_ID)
4395 values[n++] = primary_event_id(sub);
4398 raw_spin_unlock_irqrestore(&ctx->lock, flags);
4402 static int perf_read_group(struct perf_event *event,
4403 u64 read_format, char __user *buf)
4405 struct perf_event *leader = event->group_leader, *child;
4406 struct perf_event_context *ctx = leader->ctx;
4410 lockdep_assert_held(&ctx->mutex);
4412 values = kzalloc(event->read_size, GFP_KERNEL);
4416 values[0] = 1 + leader->nr_siblings;
4419 * By locking the child_mutex of the leader we effectively
4420 * lock the child list of all siblings.. XXX explain how.
4422 mutex_lock(&leader->child_mutex);
4424 ret = __perf_read_group_add(leader, read_format, values);
4428 list_for_each_entry(child, &leader->child_list, child_list) {
4429 ret = __perf_read_group_add(child, read_format, values);
4434 mutex_unlock(&leader->child_mutex);
4436 ret = event->read_size;
4437 if (copy_to_user(buf, values, event->read_size))
4442 mutex_unlock(&leader->child_mutex);
4448 static int perf_read_one(struct perf_event *event,
4449 u64 read_format, char __user *buf)
4451 u64 enabled, running;
4455 values[n++] = __perf_event_read_value(event, &enabled, &running);
4456 if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED)
4457 values[n++] = enabled;
4458 if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING)
4459 values[n++] = running;
4460 if (read_format & PERF_FORMAT_ID)
4461 values[n++] = primary_event_id(event);
4463 if (copy_to_user(buf, values, n * sizeof(u64)))
4466 return n * sizeof(u64);
4469 static bool is_event_hup(struct perf_event *event)
4473 if (event->state > PERF_EVENT_STATE_EXIT)
4476 mutex_lock(&event->child_mutex);
4477 no_children = list_empty(&event->child_list);
4478 mutex_unlock(&event->child_mutex);
4483 * Read the performance event - simple non blocking version for now
4486 __perf_read(struct perf_event *event, char __user *buf, size_t count)
4488 u64 read_format = event->attr.read_format;
4492 * Return end-of-file for a read on a event that is in
4493 * error state (i.e. because it was pinned but it couldn't be
4494 * scheduled on to the CPU at some point).
4496 if (event->state == PERF_EVENT_STATE_ERROR)
4499 if (count < event->read_size)
4502 WARN_ON_ONCE(event->ctx->parent_ctx);
4503 if (read_format & PERF_FORMAT_GROUP)
4504 ret = perf_read_group(event, read_format, buf);
4506 ret = perf_read_one(event, read_format, buf);
4512 perf_read(struct file *file, char __user *buf, size_t count, loff_t *ppos)
4514 struct perf_event *event = file->private_data;
4515 struct perf_event_context *ctx;
4518 ctx = perf_event_ctx_lock(event);
4519 ret = __perf_read(event, buf, count);
4520 perf_event_ctx_unlock(event, ctx);
4525 static __poll_t perf_poll(struct file *file, poll_table *wait)
4527 struct perf_event *event = file->private_data;
4528 struct ring_buffer *rb;
4529 __poll_t events = EPOLLHUP;
4531 poll_wait(file, &event->waitq, wait);
4533 if (is_event_hup(event))
4537 * Pin the event->rb by taking event->mmap_mutex; otherwise
4538 * perf_event_set_output() can swizzle our rb and make us miss wakeups.
4540 mutex_lock(&event->mmap_mutex);
4543 events = atomic_xchg(&rb->poll, 0);
4544 mutex_unlock(&event->mmap_mutex);
4548 static void _perf_event_reset(struct perf_event *event)
4550 (void)perf_event_read(event, false);
4551 local64_set(&event->count, 0);
4552 perf_event_update_userpage(event);
4556 * Holding the top-level event's child_mutex means that any
4557 * descendant process that has inherited this event will block
4558 * in perf_event_exit_event() if it goes to exit, thus satisfying the
4559 * task existence requirements of perf_event_enable/disable.
4561 static void perf_event_for_each_child(struct perf_event *event,
4562 void (*func)(struct perf_event *))
4564 struct perf_event *child;
4566 WARN_ON_ONCE(event->ctx->parent_ctx);
4568 mutex_lock(&event->child_mutex);
4570 list_for_each_entry(child, &event->child_list, child_list)
4572 mutex_unlock(&event->child_mutex);
4575 static void perf_event_for_each(struct perf_event *event,
4576 void (*func)(struct perf_event *))
4578 struct perf_event_context *ctx = event->ctx;
4579 struct perf_event *sibling;
4581 lockdep_assert_held(&ctx->mutex);
4583 event = event->group_leader;
4585 perf_event_for_each_child(event, func);
4586 list_for_each_entry(sibling, &event->sibling_list, group_entry)
4587 perf_event_for_each_child(sibling, func);
4590 static void __perf_event_period(struct perf_event *event,
4591 struct perf_cpu_context *cpuctx,
4592 struct perf_event_context *ctx,
4595 u64 value = *((u64 *)info);
4598 if (event->attr.freq) {
4599 event->attr.sample_freq = value;
4601 event->attr.sample_period = value;
4602 event->hw.sample_period = value;
4605 active = (event->state == PERF_EVENT_STATE_ACTIVE);
4607 perf_pmu_disable(ctx->pmu);
4609 * We could be throttled; unthrottle now to avoid the tick
4610 * trying to unthrottle while we already re-started the event.
4612 if (event->hw.interrupts == MAX_INTERRUPTS) {
4613 event->hw.interrupts = 0;
4614 perf_log_throttle(event, 1);
4616 event->pmu->stop(event, PERF_EF_UPDATE);
4619 local64_set(&event->hw.period_left, 0);
4622 event->pmu->start(event, PERF_EF_RELOAD);
4623 perf_pmu_enable(ctx->pmu);
4627 static int perf_event_period(struct perf_event *event, u64 __user *arg)
4631 if (!is_sampling_event(event))
4634 if (copy_from_user(&value, arg, sizeof(value)))
4640 if (event->attr.freq && value > sysctl_perf_event_sample_rate)
4643 event_function_call(event, __perf_event_period, &value);
4648 static const struct file_operations perf_fops;
4650 static inline int perf_fget_light(int fd, struct fd *p)
4652 struct fd f = fdget(fd);
4656 if (f.file->f_op != &perf_fops) {
4664 static int perf_event_set_output(struct perf_event *event,
4665 struct perf_event *output_event);
4666 static int perf_event_set_filter(struct perf_event *event, void __user *arg);
4667 static int perf_event_set_bpf_prog(struct perf_event *event, u32 prog_fd);
4669 static long _perf_ioctl(struct perf_event *event, unsigned int cmd, unsigned long arg)
4671 void (*func)(struct perf_event *);
4675 case PERF_EVENT_IOC_ENABLE:
4676 func = _perf_event_enable;
4678 case PERF_EVENT_IOC_DISABLE:
4679 func = _perf_event_disable;
4681 case PERF_EVENT_IOC_RESET:
4682 func = _perf_event_reset;
4685 case PERF_EVENT_IOC_REFRESH:
4686 return _perf_event_refresh(event, arg);
4688 case PERF_EVENT_IOC_PERIOD:
4689 return perf_event_period(event, (u64 __user *)arg);
4691 case PERF_EVENT_IOC_ID:
4693 u64 id = primary_event_id(event);
4695 if (copy_to_user((void __user *)arg, &id, sizeof(id)))
4700 case PERF_EVENT_IOC_SET_OUTPUT:
4704 struct perf_event *output_event;
4706 ret = perf_fget_light(arg, &output);
4709 output_event = output.file->private_data;
4710 ret = perf_event_set_output(event, output_event);
4713 ret = perf_event_set_output(event, NULL);
4718 case PERF_EVENT_IOC_SET_FILTER:
4719 return perf_event_set_filter(event, (void __user *)arg);
4721 case PERF_EVENT_IOC_SET_BPF:
4722 return perf_event_set_bpf_prog(event, arg);
4724 case PERF_EVENT_IOC_PAUSE_OUTPUT: {
4725 struct ring_buffer *rb;
4728 rb = rcu_dereference(event->rb);
4729 if (!rb || !rb->nr_pages) {
4733 rb_toggle_paused(rb, !!arg);
4738 case PERF_EVENT_IOC_QUERY_BPF:
4739 return perf_event_query_prog_array(event, (void __user *)arg);
4744 if (flags & PERF_IOC_FLAG_GROUP)
4745 perf_event_for_each(event, func);
4747 perf_event_for_each_child(event, func);
4752 static long perf_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
4754 struct perf_event *event = file->private_data;
4755 struct perf_event_context *ctx;
4758 ctx = perf_event_ctx_lock(event);
4759 ret = _perf_ioctl(event, cmd, arg);
4760 perf_event_ctx_unlock(event, ctx);
4765 #ifdef CONFIG_COMPAT
4766 static long perf_compat_ioctl(struct file *file, unsigned int cmd,
4769 switch (_IOC_NR(cmd)) {
4770 case _IOC_NR(PERF_EVENT_IOC_SET_FILTER):
4771 case _IOC_NR(PERF_EVENT_IOC_ID):
4772 /* Fix up pointer size (usually 4 -> 8 in 32-on-64-bit case */
4773 if (_IOC_SIZE(cmd) == sizeof(compat_uptr_t)) {
4774 cmd &= ~IOCSIZE_MASK;
4775 cmd |= sizeof(void *) << IOCSIZE_SHIFT;
4779 return perf_ioctl(file, cmd, arg);
4782 # define perf_compat_ioctl NULL
4785 int perf_event_task_enable(void)
4787 struct perf_event_context *ctx;
4788 struct perf_event *event;
4790 mutex_lock(¤t->perf_event_mutex);
4791 list_for_each_entry(event, ¤t->perf_event_list, owner_entry) {
4792 ctx = perf_event_ctx_lock(event);
4793 perf_event_for_each_child(event, _perf_event_enable);
4794 perf_event_ctx_unlock(event, ctx);
4796 mutex_unlock(¤t->perf_event_mutex);
4801 int perf_event_task_disable(void)
4803 struct perf_event_context *ctx;
4804 struct perf_event *event;
4806 mutex_lock(¤t->perf_event_mutex);
4807 list_for_each_entry(event, ¤t->perf_event_list, owner_entry) {
4808 ctx = perf_event_ctx_lock(event);
4809 perf_event_for_each_child(event, _perf_event_disable);
4810 perf_event_ctx_unlock(event, ctx);
4812 mutex_unlock(¤t->perf_event_mutex);
4817 static int perf_event_index(struct perf_event *event)
4819 if (event->hw.state & PERF_HES_STOPPED)
4822 if (event->state != PERF_EVENT_STATE_ACTIVE)
4825 return event->pmu->event_idx(event);
4828 static void calc_timer_values(struct perf_event *event,
4835 *now = perf_clock();
4836 ctx_time = event->shadow_ctx_time + *now;
4837 __perf_update_times(event, ctx_time, enabled, running);
4840 static void perf_event_init_userpage(struct perf_event *event)
4842 struct perf_event_mmap_page *userpg;
4843 struct ring_buffer *rb;
4846 rb = rcu_dereference(event->rb);
4850 userpg = rb->user_page;
4852 /* Allow new userspace to detect that bit 0 is deprecated */
4853 userpg->cap_bit0_is_deprecated = 1;
4854 userpg->size = offsetof(struct perf_event_mmap_page, __reserved);
4855 userpg->data_offset = PAGE_SIZE;
4856 userpg->data_size = perf_data_size(rb);
4862 void __weak arch_perf_update_userpage(
4863 struct perf_event *event, struct perf_event_mmap_page *userpg, u64 now)
4868 * Callers need to ensure there can be no nesting of this function, otherwise
4869 * the seqlock logic goes bad. We can not serialize this because the arch
4870 * code calls this from NMI context.
4872 void perf_event_update_userpage(struct perf_event *event)
4874 struct perf_event_mmap_page *userpg;
4875 struct ring_buffer *rb;
4876 u64 enabled, running, now;
4879 rb = rcu_dereference(event->rb);
4884 * compute total_time_enabled, total_time_running
4885 * based on snapshot values taken when the event
4886 * was last scheduled in.
4888 * we cannot simply called update_context_time()
4889 * because of locking issue as we can be called in
4892 calc_timer_values(event, &now, &enabled, &running);
4894 userpg = rb->user_page;
4896 * Disable preemption so as to not let the corresponding user-space
4897 * spin too long if we get preempted.
4902 userpg->index = perf_event_index(event);
4903 userpg->offset = perf_event_count(event);
4905 userpg->offset -= local64_read(&event->hw.prev_count);
4907 userpg->time_enabled = enabled +
4908 atomic64_read(&event->child_total_time_enabled);
4910 userpg->time_running = running +
4911 atomic64_read(&event->child_total_time_running);
4913 arch_perf_update_userpage(event, userpg, now);
4921 EXPORT_SYMBOL_GPL(perf_event_update_userpage);
4923 static int perf_mmap_fault(struct vm_fault *vmf)
4925 struct perf_event *event = vmf->vma->vm_file->private_data;
4926 struct ring_buffer *rb;
4927 int ret = VM_FAULT_SIGBUS;
4929 if (vmf->flags & FAULT_FLAG_MKWRITE) {
4930 if (vmf->pgoff == 0)
4936 rb = rcu_dereference(event->rb);
4940 if (vmf->pgoff && (vmf->flags & FAULT_FLAG_WRITE))
4943 vmf->page = perf_mmap_to_page(rb, vmf->pgoff);
4947 get_page(vmf->page);
4948 vmf->page->mapping = vmf->vma->vm_file->f_mapping;
4949 vmf->page->index = vmf->pgoff;
4958 static void ring_buffer_attach(struct perf_event *event,
4959 struct ring_buffer *rb)
4961 struct ring_buffer *old_rb = NULL;
4962 unsigned long flags;
4966 * Should be impossible, we set this when removing
4967 * event->rb_entry and wait/clear when adding event->rb_entry.
4969 WARN_ON_ONCE(event->rcu_pending);
4972 spin_lock_irqsave(&old_rb->event_lock, flags);
4973 list_del_rcu(&event->rb_entry);
4974 spin_unlock_irqrestore(&old_rb->event_lock, flags);
4976 event->rcu_batches = get_state_synchronize_rcu();
4977 event->rcu_pending = 1;
4981 if (event->rcu_pending) {
4982 cond_synchronize_rcu(event->rcu_batches);
4983 event->rcu_pending = 0;
4986 spin_lock_irqsave(&rb->event_lock, flags);
4987 list_add_rcu(&event->rb_entry, &rb->event_list);
4988 spin_unlock_irqrestore(&rb->event_lock, flags);
4992 * Avoid racing with perf_mmap_close(AUX): stop the event
4993 * before swizzling the event::rb pointer; if it's getting
4994 * unmapped, its aux_mmap_count will be 0 and it won't
4995 * restart. See the comment in __perf_pmu_output_stop().
4997 * Data will inevitably be lost when set_output is done in
4998 * mid-air, but then again, whoever does it like this is
4999 * not in for the data anyway.
5002 perf_event_stop(event, 0);
5004 rcu_assign_pointer(event->rb, rb);
5007 ring_buffer_put(old_rb);
5009 * Since we detached before setting the new rb, so that we
5010 * could attach the new rb, we could have missed a wakeup.
5013 wake_up_all(&event->waitq);
5017 static void ring_buffer_wakeup(struct perf_event *event)
5019 struct ring_buffer *rb;
5022 rb = rcu_dereference(event->rb);
5024 list_for_each_entry_rcu(event, &rb->event_list, rb_entry)
5025 wake_up_all(&event->waitq);
5030 struct ring_buffer *ring_buffer_get(struct perf_event *event)
5032 struct ring_buffer *rb;
5035 rb = rcu_dereference(event->rb);
5037 if (!atomic_inc_not_zero(&rb->refcount))
5045 void ring_buffer_put(struct ring_buffer *rb)
5047 if (!atomic_dec_and_test(&rb->refcount))
5050 WARN_ON_ONCE(!list_empty(&rb->event_list));
5052 call_rcu(&rb->rcu_head, rb_free_rcu);
5055 static void perf_mmap_open(struct vm_area_struct *vma)
5057 struct perf_event *event = vma->vm_file->private_data;
5059 atomic_inc(&event->mmap_count);
5060 atomic_inc(&event->rb->mmap_count);
5063 atomic_inc(&event->rb->aux_mmap_count);
5065 if (event->pmu->event_mapped)
5066 event->pmu->event_mapped(event, vma->vm_mm);
5069 static void perf_pmu_output_stop(struct perf_event *event);
5072 * A buffer can be mmap()ed multiple times; either directly through the same
5073 * event, or through other events by use of perf_event_set_output().
5075 * In order to undo the VM accounting done by perf_mmap() we need to destroy
5076 * the buffer here, where we still have a VM context. This means we need
5077 * to detach all events redirecting to us.
5079 static void perf_mmap_close(struct vm_area_struct *vma)
5081 struct perf_event *event = vma->vm_file->private_data;
5083 struct ring_buffer *rb = ring_buffer_get(event);
5084 struct user_struct *mmap_user = rb->mmap_user;
5085 int mmap_locked = rb->mmap_locked;
5086 unsigned long size = perf_data_size(rb);
5088 if (event->pmu->event_unmapped)
5089 event->pmu->event_unmapped(event, vma->vm_mm);
5092 * rb->aux_mmap_count will always drop before rb->mmap_count and
5093 * event->mmap_count, so it is ok to use event->mmap_mutex to
5094 * serialize with perf_mmap here.
5096 if (rb_has_aux(rb) && vma->vm_pgoff == rb->aux_pgoff &&
5097 atomic_dec_and_mutex_lock(&rb->aux_mmap_count, &event->mmap_mutex)) {
5099 * Stop all AUX events that are writing to this buffer,
5100 * so that we can free its AUX pages and corresponding PMU
5101 * data. Note that after rb::aux_mmap_count dropped to zero,
5102 * they won't start any more (see perf_aux_output_begin()).
5104 perf_pmu_output_stop(event);
5106 /* now it's safe to free the pages */
5107 atomic_long_sub(rb->aux_nr_pages, &mmap_user->locked_vm);
5108 vma->vm_mm->pinned_vm -= rb->aux_mmap_locked;
5110 /* this has to be the last one */
5112 WARN_ON_ONCE(atomic_read(&rb->aux_refcount));
5114 mutex_unlock(&event->mmap_mutex);
5117 atomic_dec(&rb->mmap_count);
5119 if (!atomic_dec_and_mutex_lock(&event->mmap_count, &event->mmap_mutex))
5122 ring_buffer_attach(event, NULL);
5123 mutex_unlock(&event->mmap_mutex);
5125 /* If there's still other mmap()s of this buffer, we're done. */
5126 if (atomic_read(&rb->mmap_count))
5130 * No other mmap()s, detach from all other events that might redirect
5131 * into the now unreachable buffer. Somewhat complicated by the
5132 * fact that rb::event_lock otherwise nests inside mmap_mutex.
5136 list_for_each_entry_rcu(event, &rb->event_list, rb_entry) {
5137 if (!atomic_long_inc_not_zero(&event->refcount)) {
5139 * This event is en-route to free_event() which will
5140 * detach it and remove it from the list.
5146 mutex_lock(&event->mmap_mutex);
5148 * Check we didn't race with perf_event_set_output() which can
5149 * swizzle the rb from under us while we were waiting to
5150 * acquire mmap_mutex.
5152 * If we find a different rb; ignore this event, a next
5153 * iteration will no longer find it on the list. We have to
5154 * still restart the iteration to make sure we're not now
5155 * iterating the wrong list.
5157 if (event->rb == rb)
5158 ring_buffer_attach(event, NULL);
5160 mutex_unlock(&event->mmap_mutex);
5164 * Restart the iteration; either we're on the wrong list or
5165 * destroyed its integrity by doing a deletion.
5172 * It could be there's still a few 0-ref events on the list; they'll
5173 * get cleaned up by free_event() -- they'll also still have their
5174 * ref on the rb and will free it whenever they are done with it.
5176 * Aside from that, this buffer is 'fully' detached and unmapped,
5177 * undo the VM accounting.
5180 atomic_long_sub((size >> PAGE_SHIFT) + 1, &mmap_user->locked_vm);
5181 vma->vm_mm->pinned_vm -= mmap_locked;
5182 free_uid(mmap_user);
5185 ring_buffer_put(rb); /* could be last */
5188 static const struct vm_operations_struct perf_mmap_vmops = {
5189 .open = perf_mmap_open,
5190 .close = perf_mmap_close, /* non mergable */
5191 .fault = perf_mmap_fault,
5192 .page_mkwrite = perf_mmap_fault,
5195 static int perf_mmap(struct file *file, struct vm_area_struct *vma)
5197 struct perf_event *event = file->private_data;
5198 unsigned long user_locked, user_lock_limit;
5199 struct user_struct *user = current_user();
5200 unsigned long locked, lock_limit;
5201 struct ring_buffer *rb = NULL;
5202 unsigned long vma_size;
5203 unsigned long nr_pages;
5204 long user_extra = 0, extra = 0;
5205 int ret = 0, flags = 0;
5208 * Don't allow mmap() of inherited per-task counters. This would
5209 * create a performance issue due to all children writing to the
5212 if (event->cpu == -1 && event->attr.inherit)
5215 if (!(vma->vm_flags & VM_SHARED))
5218 vma_size = vma->vm_end - vma->vm_start;
5220 if (vma->vm_pgoff == 0) {
5221 nr_pages = (vma_size / PAGE_SIZE) - 1;
5224 * AUX area mapping: if rb->aux_nr_pages != 0, it's already
5225 * mapped, all subsequent mappings should have the same size
5226 * and offset. Must be above the normal perf buffer.
5228 u64 aux_offset, aux_size;
5233 nr_pages = vma_size / PAGE_SIZE;
5235 mutex_lock(&event->mmap_mutex);
5242 aux_offset = READ_ONCE(rb->user_page->aux_offset);
5243 aux_size = READ_ONCE(rb->user_page->aux_size);
5245 if (aux_offset < perf_data_size(rb) + PAGE_SIZE)
5248 if (aux_offset != vma->vm_pgoff << PAGE_SHIFT)
5251 /* already mapped with a different offset */
5252 if (rb_has_aux(rb) && rb->aux_pgoff != vma->vm_pgoff)
5255 if (aux_size != vma_size || aux_size != nr_pages * PAGE_SIZE)
5258 /* already mapped with a different size */
5259 if (rb_has_aux(rb) && rb->aux_nr_pages != nr_pages)
5262 if (!is_power_of_2(nr_pages))
5265 if (!atomic_inc_not_zero(&rb->mmap_count))
5268 if (rb_has_aux(rb)) {
5269 atomic_inc(&rb->aux_mmap_count);
5274 atomic_set(&rb->aux_mmap_count, 1);
5275 user_extra = nr_pages;
5281 * If we have rb pages ensure they're a power-of-two number, so we
5282 * can do bitmasks instead of modulo.
5284 if (nr_pages != 0 && !is_power_of_2(nr_pages))
5287 if (vma_size != PAGE_SIZE * (1 + nr_pages))
5290 WARN_ON_ONCE(event->ctx->parent_ctx);
5292 mutex_lock(&event->mmap_mutex);
5294 if (event->rb->nr_pages != nr_pages) {
5299 if (!atomic_inc_not_zero(&event->rb->mmap_count)) {
5301 * Raced against perf_mmap_close() through
5302 * perf_event_set_output(). Try again, hope for better
5305 mutex_unlock(&event->mmap_mutex);
5312 user_extra = nr_pages + 1;
5315 user_lock_limit = sysctl_perf_event_mlock >> (PAGE_SHIFT - 10);
5318 * Increase the limit linearly with more CPUs:
5320 user_lock_limit *= num_online_cpus();
5322 user_locked = atomic_long_read(&user->locked_vm) + user_extra;
5324 if (user_locked > user_lock_limit)
5325 extra = user_locked - user_lock_limit;
5327 lock_limit = rlimit(RLIMIT_MEMLOCK);
5328 lock_limit >>= PAGE_SHIFT;
5329 locked = vma->vm_mm->pinned_vm + extra;
5331 if ((locked > lock_limit) && perf_paranoid_tracepoint_raw() &&
5332 !capable(CAP_IPC_LOCK)) {
5337 WARN_ON(!rb && event->rb);
5339 if (vma->vm_flags & VM_WRITE)
5340 flags |= RING_BUFFER_WRITABLE;
5343 rb = rb_alloc(nr_pages,
5344 event->attr.watermark ? event->attr.wakeup_watermark : 0,
5352 atomic_set(&rb->mmap_count, 1);
5353 rb->mmap_user = get_current_user();
5354 rb->mmap_locked = extra;
5356 ring_buffer_attach(event, rb);
5358 perf_event_init_userpage(event);
5359 perf_event_update_userpage(event);
5361 ret = rb_alloc_aux(rb, event, vma->vm_pgoff, nr_pages,
5362 event->attr.aux_watermark, flags);
5364 rb->aux_mmap_locked = extra;
5369 atomic_long_add(user_extra, &user->locked_vm);
5370 vma->vm_mm->pinned_vm += extra;
5372 atomic_inc(&event->mmap_count);
5374 atomic_dec(&rb->mmap_count);
5377 mutex_unlock(&event->mmap_mutex);
5380 * Since pinned accounting is per vm we cannot allow fork() to copy our
5383 vma->vm_flags |= VM_DONTCOPY | VM_DONTEXPAND | VM_DONTDUMP;
5384 vma->vm_ops = &perf_mmap_vmops;
5386 if (event->pmu->event_mapped)
5387 event->pmu->event_mapped(event, vma->vm_mm);
5392 static int perf_fasync(int fd, struct file *filp, int on)
5394 struct inode *inode = file_inode(filp);
5395 struct perf_event *event = filp->private_data;
5399 retval = fasync_helper(fd, filp, on, &event->fasync);
5400 inode_unlock(inode);
5408 static const struct file_operations perf_fops = {
5409 .llseek = no_llseek,
5410 .release = perf_release,
5413 .unlocked_ioctl = perf_ioctl,
5414 .compat_ioctl = perf_compat_ioctl,
5416 .fasync = perf_fasync,
5422 * If there's data, ensure we set the poll() state and publish everything
5423 * to user-space before waking everybody up.
5426 static inline struct fasync_struct **perf_event_fasync(struct perf_event *event)
5428 /* only the parent has fasync state */
5430 event = event->parent;
5431 return &event->fasync;
5434 void perf_event_wakeup(struct perf_event *event)
5436 ring_buffer_wakeup(event);
5438 if (event->pending_kill) {
5439 kill_fasync(perf_event_fasync(event), SIGIO, event->pending_kill);
5440 event->pending_kill = 0;
5444 static void perf_pending_event(struct irq_work *entry)
5446 struct perf_event *event = container_of(entry,
5447 struct perf_event, pending);
5450 rctx = perf_swevent_get_recursion_context();
5452 * If we 'fail' here, that's OK, it means recursion is already disabled
5453 * and we won't recurse 'further'.
5456 if (event->pending_disable) {
5457 event->pending_disable = 0;
5458 perf_event_disable_local(event);
5461 if (event->pending_wakeup) {
5462 event->pending_wakeup = 0;
5463 perf_event_wakeup(event);
5467 perf_swevent_put_recursion_context(rctx);
5471 * We assume there is only KVM supporting the callbacks.
5472 * Later on, we might change it to a list if there is
5473 * another virtualization implementation supporting the callbacks.
5475 struct perf_guest_info_callbacks *perf_guest_cbs;
5477 int perf_register_guest_info_callbacks(struct perf_guest_info_callbacks *cbs)
5479 perf_guest_cbs = cbs;
5482 EXPORT_SYMBOL_GPL(perf_register_guest_info_callbacks);
5484 int perf_unregister_guest_info_callbacks(struct perf_guest_info_callbacks *cbs)
5486 perf_guest_cbs = NULL;
5489 EXPORT_SYMBOL_GPL(perf_unregister_guest_info_callbacks);
5492 perf_output_sample_regs(struct perf_output_handle *handle,
5493 struct pt_regs *regs, u64 mask)
5496 DECLARE_BITMAP(_mask, 64);
5498 bitmap_from_u64(_mask, mask);
5499 for_each_set_bit(bit, _mask, sizeof(mask) * BITS_PER_BYTE) {
5502 val = perf_reg_value(regs, bit);
5503 perf_output_put(handle, val);
5507 static void perf_sample_regs_user(struct perf_regs *regs_user,
5508 struct pt_regs *regs,
5509 struct pt_regs *regs_user_copy)
5511 if (user_mode(regs)) {
5512 regs_user->abi = perf_reg_abi(current);
5513 regs_user->regs = regs;
5514 } else if (current->mm) {
5515 perf_get_regs_user(regs_user, regs, regs_user_copy);
5517 regs_user->abi = PERF_SAMPLE_REGS_ABI_NONE;
5518 regs_user->regs = NULL;
5522 static void perf_sample_regs_intr(struct perf_regs *regs_intr,
5523 struct pt_regs *regs)
5525 regs_intr->regs = regs;
5526 regs_intr->abi = perf_reg_abi(current);
5531 * Get remaining task size from user stack pointer.
5533 * It'd be better to take stack vma map and limit this more
5534 * precisly, but there's no way to get it safely under interrupt,
5535 * so using TASK_SIZE as limit.
5537 static u64 perf_ustack_task_size(struct pt_regs *regs)
5539 unsigned long addr = perf_user_stack_pointer(regs);
5541 if (!addr || addr >= TASK_SIZE)
5544 return TASK_SIZE - addr;
5548 perf_sample_ustack_size(u16 stack_size, u16 header_size,
5549 struct pt_regs *regs)
5553 /* No regs, no stack pointer, no dump. */
5558 * Check if we fit in with the requested stack size into the:
5560 * If we don't, we limit the size to the TASK_SIZE.
5562 * - remaining sample size
5563 * If we don't, we customize the stack size to
5564 * fit in to the remaining sample size.
5567 task_size = min((u64) USHRT_MAX, perf_ustack_task_size(regs));
5568 stack_size = min(stack_size, (u16) task_size);
5570 /* Current header size plus static size and dynamic size. */
5571 header_size += 2 * sizeof(u64);
5573 /* Do we fit in with the current stack dump size? */
5574 if ((u16) (header_size + stack_size) < header_size) {
5576 * If we overflow the maximum size for the sample,
5577 * we customize the stack dump size to fit in.
5579 stack_size = USHRT_MAX - header_size - sizeof(u64);
5580 stack_size = round_up(stack_size, sizeof(u64));
5587 perf_output_sample_ustack(struct perf_output_handle *handle, u64 dump_size,
5588 struct pt_regs *regs)
5590 /* Case of a kernel thread, nothing to dump */
5593 perf_output_put(handle, size);
5602 * - the size requested by user or the best one we can fit
5603 * in to the sample max size
5605 * - user stack dump data
5607 * - the actual dumped size
5611 perf_output_put(handle, dump_size);
5614 sp = perf_user_stack_pointer(regs);
5615 rem = __output_copy_user(handle, (void *) sp, dump_size);
5616 dyn_size = dump_size - rem;
5618 perf_output_skip(handle, rem);
5621 perf_output_put(handle, dyn_size);
5625 static void __perf_event_header__init_id(struct perf_event_header *header,
5626 struct perf_sample_data *data,
5627 struct perf_event *event)
5629 u64 sample_type = event->attr.sample_type;
5631 data->type = sample_type;
5632 header->size += event->id_header_size;
5634 if (sample_type & PERF_SAMPLE_TID) {
5635 /* namespace issues */
5636 data->tid_entry.pid = perf_event_pid(event, current);
5637 data->tid_entry.tid = perf_event_tid(event, current);
5640 if (sample_type & PERF_SAMPLE_TIME)
5641 data->time = perf_event_clock(event);
5643 if (sample_type & (PERF_SAMPLE_ID | PERF_SAMPLE_IDENTIFIER))
5644 data->id = primary_event_id(event);
5646 if (sample_type & PERF_SAMPLE_STREAM_ID)
5647 data->stream_id = event->id;
5649 if (sample_type & PERF_SAMPLE_CPU) {
5650 data->cpu_entry.cpu = raw_smp_processor_id();
5651 data->cpu_entry.reserved = 0;
5655 void perf_event_header__init_id(struct perf_event_header *header,
5656 struct perf_sample_data *data,
5657 struct perf_event *event)
5659 if (event->attr.sample_id_all)
5660 __perf_event_header__init_id(header, data, event);
5663 static void __perf_event__output_id_sample(struct perf_output_handle *handle,
5664 struct perf_sample_data *data)
5666 u64 sample_type = data->type;
5668 if (sample_type & PERF_SAMPLE_TID)
5669 perf_output_put(handle, data->tid_entry);
5671 if (sample_type & PERF_SAMPLE_TIME)
5672 perf_output_put(handle, data->time);
5674 if (sample_type & PERF_SAMPLE_ID)
5675 perf_output_put(handle, data->id);
5677 if (sample_type & PERF_SAMPLE_STREAM_ID)
5678 perf_output_put(handle, data->stream_id);
5680 if (sample_type & PERF_SAMPLE_CPU)
5681 perf_output_put(handle, data->cpu_entry);
5683 if (sample_type & PERF_SAMPLE_IDENTIFIER)
5684 perf_output_put(handle, data->id);
5687 void perf_event__output_id_sample(struct perf_event *event,
5688 struct perf_output_handle *handle,
5689 struct perf_sample_data *sample)
5691 if (event->attr.sample_id_all)
5692 __perf_event__output_id_sample(handle, sample);
5695 static void perf_output_read_one(struct perf_output_handle *handle,
5696 struct perf_event *event,
5697 u64 enabled, u64 running)
5699 u64 read_format = event->attr.read_format;
5703 values[n++] = perf_event_count(event);
5704 if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED) {
5705 values[n++] = enabled +
5706 atomic64_read(&event->child_total_time_enabled);
5708 if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING) {
5709 values[n++] = running +
5710 atomic64_read(&event->child_total_time_running);
5712 if (read_format & PERF_FORMAT_ID)
5713 values[n++] = primary_event_id(event);
5715 __output_copy(handle, values, n * sizeof(u64));
5718 static void perf_output_read_group(struct perf_output_handle *handle,
5719 struct perf_event *event,
5720 u64 enabled, u64 running)
5722 struct perf_event *leader = event->group_leader, *sub;
5723 u64 read_format = event->attr.read_format;
5727 values[n++] = 1 + leader->nr_siblings;
5729 if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED)
5730 values[n++] = enabled;
5732 if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING)
5733 values[n++] = running;
5735 if (leader != event)
5736 leader->pmu->read(leader);
5738 values[n++] = perf_event_count(leader);
5739 if (read_format & PERF_FORMAT_ID)
5740 values[n++] = primary_event_id(leader);
5742 __output_copy(handle, values, n * sizeof(u64));
5744 list_for_each_entry(sub, &leader->sibling_list, group_entry) {
5747 if ((sub != event) &&
5748 (sub->state == PERF_EVENT_STATE_ACTIVE))
5749 sub->pmu->read(sub);
5751 values[n++] = perf_event_count(sub);
5752 if (read_format & PERF_FORMAT_ID)
5753 values[n++] = primary_event_id(sub);
5755 __output_copy(handle, values, n * sizeof(u64));
5759 #define PERF_FORMAT_TOTAL_TIMES (PERF_FORMAT_TOTAL_TIME_ENABLED|\
5760 PERF_FORMAT_TOTAL_TIME_RUNNING)
5763 * XXX PERF_SAMPLE_READ vs inherited events seems difficult.
5765 * The problem is that its both hard and excessively expensive to iterate the
5766 * child list, not to mention that its impossible to IPI the children running
5767 * on another CPU, from interrupt/NMI context.
5769 static void perf_output_read(struct perf_output_handle *handle,
5770 struct perf_event *event)
5772 u64 enabled = 0, running = 0, now;
5773 u64 read_format = event->attr.read_format;
5776 * compute total_time_enabled, total_time_running
5777 * based on snapshot values taken when the event
5778 * was last scheduled in.
5780 * we cannot simply called update_context_time()
5781 * because of locking issue as we are called in
5784 if (read_format & PERF_FORMAT_TOTAL_TIMES)
5785 calc_timer_values(event, &now, &enabled, &running);
5787 if (event->attr.read_format & PERF_FORMAT_GROUP)
5788 perf_output_read_group(handle, event, enabled, running);
5790 perf_output_read_one(handle, event, enabled, running);
5793 void perf_output_sample(struct perf_output_handle *handle,
5794 struct perf_event_header *header,
5795 struct perf_sample_data *data,
5796 struct perf_event *event)
5798 u64 sample_type = data->type;
5800 perf_output_put(handle, *header);
5802 if (sample_type & PERF_SAMPLE_IDENTIFIER)
5803 perf_output_put(handle, data->id);
5805 if (sample_type & PERF_SAMPLE_IP)
5806 perf_output_put(handle, data->ip);
5808 if (sample_type & PERF_SAMPLE_TID)
5809 perf_output_put(handle, data->tid_entry);
5811 if (sample_type & PERF_SAMPLE_TIME)
5812 perf_output_put(handle, data->time);
5814 if (sample_type & PERF_SAMPLE_ADDR)
5815 perf_output_put(handle, data->addr);
5817 if (sample_type & PERF_SAMPLE_ID)
5818 perf_output_put(handle, data->id);
5820 if (sample_type & PERF_SAMPLE_STREAM_ID)
5821 perf_output_put(handle, data->stream_id);
5823 if (sample_type & PERF_SAMPLE_CPU)
5824 perf_output_put(handle, data->cpu_entry);
5826 if (sample_type & PERF_SAMPLE_PERIOD)
5827 perf_output_put(handle, data->period);
5829 if (sample_type & PERF_SAMPLE_READ)
5830 perf_output_read(handle, event);
5832 if (sample_type & PERF_SAMPLE_CALLCHAIN) {
5835 size += data->callchain->nr;
5836 size *= sizeof(u64);
5837 __output_copy(handle, data->callchain, size);
5840 if (sample_type & PERF_SAMPLE_RAW) {
5841 struct perf_raw_record *raw = data->raw;
5844 struct perf_raw_frag *frag = &raw->frag;
5846 perf_output_put(handle, raw->size);
5849 __output_custom(handle, frag->copy,
5850 frag->data, frag->size);
5852 __output_copy(handle, frag->data,
5855 if (perf_raw_frag_last(frag))
5860 __output_skip(handle, NULL, frag->pad);
5866 .size = sizeof(u32),
5869 perf_output_put(handle, raw);
5873 if (sample_type & PERF_SAMPLE_BRANCH_STACK) {
5874 if (data->br_stack) {
5877 size = data->br_stack->nr
5878 * sizeof(struct perf_branch_entry);
5880 perf_output_put(handle, data->br_stack->nr);
5881 perf_output_copy(handle, data->br_stack->entries, size);
5884 * we always store at least the value of nr
5887 perf_output_put(handle, nr);
5891 if (sample_type & PERF_SAMPLE_REGS_USER) {
5892 u64 abi = data->regs_user.abi;
5895 * If there are no regs to dump, notice it through
5896 * first u64 being zero (PERF_SAMPLE_REGS_ABI_NONE).
5898 perf_output_put(handle, abi);
5901 u64 mask = event->attr.sample_regs_user;
5902 perf_output_sample_regs(handle,
5903 data->regs_user.regs,
5908 if (sample_type & PERF_SAMPLE_STACK_USER) {
5909 perf_output_sample_ustack(handle,
5910 data->stack_user_size,
5911 data->regs_user.regs);
5914 if (sample_type & PERF_SAMPLE_WEIGHT)
5915 perf_output_put(handle, data->weight);
5917 if (sample_type & PERF_SAMPLE_DATA_SRC)
5918 perf_output_put(handle, data->data_src.val);
5920 if (sample_type & PERF_SAMPLE_TRANSACTION)
5921 perf_output_put(handle, data->txn);
5923 if (sample_type & PERF_SAMPLE_REGS_INTR) {
5924 u64 abi = data->regs_intr.abi;
5926 * If there are no regs to dump, notice it through
5927 * first u64 being zero (PERF_SAMPLE_REGS_ABI_NONE).
5929 perf_output_put(handle, abi);
5932 u64 mask = event->attr.sample_regs_intr;
5934 perf_output_sample_regs(handle,
5935 data->regs_intr.regs,
5940 if (sample_type & PERF_SAMPLE_PHYS_ADDR)
5941 perf_output_put(handle, data->phys_addr);
5943 if (!event->attr.watermark) {
5944 int wakeup_events = event->attr.wakeup_events;
5946 if (wakeup_events) {
5947 struct ring_buffer *rb = handle->rb;
5948 int events = local_inc_return(&rb->events);
5950 if (events >= wakeup_events) {
5951 local_sub(wakeup_events, &rb->events);
5952 local_inc(&rb->wakeup);
5958 static u64 perf_virt_to_phys(u64 virt)
5961 struct page *p = NULL;
5966 if (virt >= TASK_SIZE) {
5967 /* If it's vmalloc()d memory, leave phys_addr as 0 */
5968 if (virt_addr_valid((void *)(uintptr_t)virt) &&
5969 !(virt >= VMALLOC_START && virt < VMALLOC_END))
5970 phys_addr = (u64)virt_to_phys((void *)(uintptr_t)virt);
5973 * Walking the pages tables for user address.
5974 * Interrupts are disabled, so it prevents any tear down
5975 * of the page tables.
5976 * Try IRQ-safe __get_user_pages_fast first.
5977 * If failed, leave phys_addr as 0.
5979 if ((current->mm != NULL) &&
5980 (__get_user_pages_fast(virt, 1, 0, &p) == 1))
5981 phys_addr = page_to_phys(p) + virt % PAGE_SIZE;
5990 static struct perf_callchain_entry __empty_callchain = { .nr = 0, };
5992 static struct perf_callchain_entry *
5993 perf_callchain(struct perf_event *event, struct pt_regs *regs)
5995 bool kernel = !event->attr.exclude_callchain_kernel;
5996 bool user = !event->attr.exclude_callchain_user;
5997 /* Disallow cross-task user callchains. */
5998 bool crosstask = event->ctx->task && event->ctx->task != current;
5999 const u32 max_stack = event->attr.sample_max_stack;
6000 struct perf_callchain_entry *callchain;
6002 if (!kernel && !user)
6003 return &__empty_callchain;
6005 callchain = get_perf_callchain(regs, 0, kernel, user,
6006 max_stack, crosstask, true);
6007 return callchain ?: &__empty_callchain;
6010 void perf_prepare_sample(struct perf_event_header *header,
6011 struct perf_sample_data *data,
6012 struct perf_event *event,
6013 struct pt_regs *regs)
6015 u64 sample_type = event->attr.sample_type;
6017 header->type = PERF_RECORD_SAMPLE;
6018 header->size = sizeof(*header) + event->header_size;
6021 header->misc |= perf_misc_flags(regs);
6023 __perf_event_header__init_id(header, data, event);
6025 if (sample_type & PERF_SAMPLE_IP)
6026 data->ip = perf_instruction_pointer(regs);
6028 if (sample_type & PERF_SAMPLE_CALLCHAIN) {
6031 data->callchain = perf_callchain(event, regs);
6032 size += data->callchain->nr;
6034 header->size += size * sizeof(u64);
6037 if (sample_type & PERF_SAMPLE_RAW) {
6038 struct perf_raw_record *raw = data->raw;
6042 struct perf_raw_frag *frag = &raw->frag;
6047 if (perf_raw_frag_last(frag))
6052 size = round_up(sum + sizeof(u32), sizeof(u64));
6053 raw->size = size - sizeof(u32);
6054 frag->pad = raw->size - sum;
6059 header->size += size;
6062 if (sample_type & PERF_SAMPLE_BRANCH_STACK) {
6063 int size = sizeof(u64); /* nr */
6064 if (data->br_stack) {
6065 size += data->br_stack->nr
6066 * sizeof(struct perf_branch_entry);
6068 header->size += size;
6071 if (sample_type & (PERF_SAMPLE_REGS_USER | PERF_SAMPLE_STACK_USER))
6072 perf_sample_regs_user(&data->regs_user, regs,
6073 &data->regs_user_copy);
6075 if (sample_type & PERF_SAMPLE_REGS_USER) {
6076 /* regs dump ABI info */
6077 int size = sizeof(u64);
6079 if (data->regs_user.regs) {
6080 u64 mask = event->attr.sample_regs_user;
6081 size += hweight64(mask) * sizeof(u64);
6084 header->size += size;
6087 if (sample_type & PERF_SAMPLE_STACK_USER) {
6089 * Either we need PERF_SAMPLE_STACK_USER bit to be allways
6090 * processed as the last one or have additional check added
6091 * in case new sample type is added, because we could eat
6092 * up the rest of the sample size.
6094 u16 stack_size = event->attr.sample_stack_user;
6095 u16 size = sizeof(u64);
6097 stack_size = perf_sample_ustack_size(stack_size, header->size,
6098 data->regs_user.regs);
6101 * If there is something to dump, add space for the dump
6102 * itself and for the field that tells the dynamic size,
6103 * which is how many have been actually dumped.
6106 size += sizeof(u64) + stack_size;
6108 data->stack_user_size = stack_size;
6109 header->size += size;
6112 if (sample_type & PERF_SAMPLE_REGS_INTR) {
6113 /* regs dump ABI info */
6114 int size = sizeof(u64);
6116 perf_sample_regs_intr(&data->regs_intr, regs);
6118 if (data->regs_intr.regs) {
6119 u64 mask = event->attr.sample_regs_intr;
6121 size += hweight64(mask) * sizeof(u64);
6124 header->size += size;
6127 if (sample_type & PERF_SAMPLE_PHYS_ADDR)
6128 data->phys_addr = perf_virt_to_phys(data->addr);
6131 static void __always_inline
6132 __perf_event_output(struct perf_event *event,
6133 struct perf_sample_data *data,
6134 struct pt_regs *regs,
6135 int (*output_begin)(struct perf_output_handle *,
6136 struct perf_event *,
6139 struct perf_output_handle handle;
6140 struct perf_event_header header;
6142 /* protect the callchain buffers */
6145 perf_prepare_sample(&header, data, event, regs);
6147 if (output_begin(&handle, event, header.size))
6150 perf_output_sample(&handle, &header, data, event);
6152 perf_output_end(&handle);
6159 perf_event_output_forward(struct perf_event *event,
6160 struct perf_sample_data *data,
6161 struct pt_regs *regs)
6163 __perf_event_output(event, data, regs, perf_output_begin_forward);
6167 perf_event_output_backward(struct perf_event *event,
6168 struct perf_sample_data *data,
6169 struct pt_regs *regs)
6171 __perf_event_output(event, data, regs, perf_output_begin_backward);
6175 perf_event_output(struct perf_event *event,
6176 struct perf_sample_data *data,
6177 struct pt_regs *regs)
6179 __perf_event_output(event, data, regs, perf_output_begin);
6186 struct perf_read_event {
6187 struct perf_event_header header;
6194 perf_event_read_event(struct perf_event *event,
6195 struct task_struct *task)
6197 struct perf_output_handle handle;
6198 struct perf_sample_data sample;
6199 struct perf_read_event read_event = {
6201 .type = PERF_RECORD_READ,
6203 .size = sizeof(read_event) + event->read_size,
6205 .pid = perf_event_pid(event, task),
6206 .tid = perf_event_tid(event, task),
6210 perf_event_header__init_id(&read_event.header, &sample, event);
6211 ret = perf_output_begin(&handle, event, read_event.header.size);
6215 perf_output_put(&handle, read_event);
6216 perf_output_read(&handle, event);
6217 perf_event__output_id_sample(event, &handle, &sample);
6219 perf_output_end(&handle);
6222 typedef void (perf_iterate_f)(struct perf_event *event, void *data);
6225 perf_iterate_ctx(struct perf_event_context *ctx,
6226 perf_iterate_f output,
6227 void *data, bool all)
6229 struct perf_event *event;
6231 list_for_each_entry_rcu(event, &ctx->event_list, event_entry) {
6233 if (event->state < PERF_EVENT_STATE_INACTIVE)
6235 if (!event_filter_match(event))
6239 output(event, data);
6243 static void perf_iterate_sb_cpu(perf_iterate_f output, void *data)
6245 struct pmu_event_list *pel = this_cpu_ptr(&pmu_sb_events);
6246 struct perf_event *event;
6248 list_for_each_entry_rcu(event, &pel->list, sb_list) {
6250 * Skip events that are not fully formed yet; ensure that
6251 * if we observe event->ctx, both event and ctx will be
6252 * complete enough. See perf_install_in_context().
6254 if (!smp_load_acquire(&event->ctx))
6257 if (event->state < PERF_EVENT_STATE_INACTIVE)
6259 if (!event_filter_match(event))
6261 output(event, data);
6266 * Iterate all events that need to receive side-band events.
6268 * For new callers; ensure that account_pmu_sb_event() includes
6269 * your event, otherwise it might not get delivered.
6272 perf_iterate_sb(perf_iterate_f output, void *data,
6273 struct perf_event_context *task_ctx)
6275 struct perf_event_context *ctx;
6282 * If we have task_ctx != NULL we only notify the task context itself.
6283 * The task_ctx is set only for EXIT events before releasing task
6287 perf_iterate_ctx(task_ctx, output, data, false);
6291 perf_iterate_sb_cpu(output, data);
6293 for_each_task_context_nr(ctxn) {
6294 ctx = rcu_dereference(current->perf_event_ctxp[ctxn]);
6296 perf_iterate_ctx(ctx, output, data, false);
6304 * Clear all file-based filters at exec, they'll have to be
6305 * re-instated when/if these objects are mmapped again.
6307 static void perf_event_addr_filters_exec(struct perf_event *event, void *data)
6309 struct perf_addr_filters_head *ifh = perf_event_addr_filters(event);
6310 struct perf_addr_filter *filter;
6311 unsigned int restart = 0, count = 0;
6312 unsigned long flags;
6314 if (!has_addr_filter(event))
6317 raw_spin_lock_irqsave(&ifh->lock, flags);
6318 list_for_each_entry(filter, &ifh->list, entry) {
6319 if (filter->inode) {
6320 event->addr_filters_offs[count] = 0;
6328 event->addr_filters_gen++;
6329 raw_spin_unlock_irqrestore(&ifh->lock, flags);
6332 perf_event_stop(event, 1);
6335 void perf_event_exec(void)
6337 struct perf_event_context *ctx;
6341 for_each_task_context_nr(ctxn) {
6342 ctx = current->perf_event_ctxp[ctxn];
6346 perf_event_enable_on_exec(ctxn);
6348 perf_iterate_ctx(ctx, perf_event_addr_filters_exec, NULL,
6354 struct remote_output {
6355 struct ring_buffer *rb;
6359 static void __perf_event_output_stop(struct perf_event *event, void *data)
6361 struct perf_event *parent = event->parent;
6362 struct remote_output *ro = data;
6363 struct ring_buffer *rb = ro->rb;
6364 struct stop_event_data sd = {
6368 if (!has_aux(event))
6375 * In case of inheritance, it will be the parent that links to the
6376 * ring-buffer, but it will be the child that's actually using it.
6378 * We are using event::rb to determine if the event should be stopped,
6379 * however this may race with ring_buffer_attach() (through set_output),
6380 * which will make us skip the event that actually needs to be stopped.
6381 * So ring_buffer_attach() has to stop an aux event before re-assigning
6384 if (rcu_dereference(parent->rb) == rb)
6385 ro->err = __perf_event_stop(&sd);
6388 static int __perf_pmu_output_stop(void *info)
6390 struct perf_event *event = info;
6391 struct pmu *pmu = event->pmu;
6392 struct perf_cpu_context *cpuctx = this_cpu_ptr(pmu->pmu_cpu_context);
6393 struct remote_output ro = {
6398 perf_iterate_ctx(&cpuctx->ctx, __perf_event_output_stop, &ro, false);
6399 if (cpuctx->task_ctx)
6400 perf_iterate_ctx(cpuctx->task_ctx, __perf_event_output_stop,
6407 static void perf_pmu_output_stop(struct perf_event *event)
6409 struct perf_event *iter;
6414 list_for_each_entry_rcu(iter, &event->rb->event_list, rb_entry) {
6416 * For per-CPU events, we need to make sure that neither they
6417 * nor their children are running; for cpu==-1 events it's
6418 * sufficient to stop the event itself if it's active, since
6419 * it can't have children.
6423 cpu = READ_ONCE(iter->oncpu);
6428 err = cpu_function_call(cpu, __perf_pmu_output_stop, event);
6429 if (err == -EAGAIN) {
6438 * task tracking -- fork/exit
6440 * enabled by: attr.comm | attr.mmap | attr.mmap2 | attr.mmap_data | attr.task
6443 struct perf_task_event {
6444 struct task_struct *task;
6445 struct perf_event_context *task_ctx;
6448 struct perf_event_header header;
6458 static int perf_event_task_match(struct perf_event *event)
6460 return event->attr.comm || event->attr.mmap ||
6461 event->attr.mmap2 || event->attr.mmap_data ||
6465 static void perf_event_task_output(struct perf_event *event,
6468 struct perf_task_event *task_event = data;
6469 struct perf_output_handle handle;
6470 struct perf_sample_data sample;
6471 struct task_struct *task = task_event->task;
6472 int ret, size = task_event->event_id.header.size;
6474 if (!perf_event_task_match(event))
6477 perf_event_header__init_id(&task_event->event_id.header, &sample, event);
6479 ret = perf_output_begin(&handle, event,
6480 task_event->event_id.header.size);
6484 task_event->event_id.pid = perf_event_pid(event, task);
6485 task_event->event_id.ppid = perf_event_pid(event, current);
6487 task_event->event_id.tid = perf_event_tid(event, task);
6488 task_event->event_id.ptid = perf_event_tid(event, current);
6490 task_event->event_id.time = perf_event_clock(event);
6492 perf_output_put(&handle, task_event->event_id);
6494 perf_event__output_id_sample(event, &handle, &sample);
6496 perf_output_end(&handle);
6498 task_event->event_id.header.size = size;
6501 static void perf_event_task(struct task_struct *task,
6502 struct perf_event_context *task_ctx,
6505 struct perf_task_event task_event;
6507 if (!atomic_read(&nr_comm_events) &&
6508 !atomic_read(&nr_mmap_events) &&
6509 !atomic_read(&nr_task_events))
6512 task_event = (struct perf_task_event){
6514 .task_ctx = task_ctx,
6517 .type = new ? PERF_RECORD_FORK : PERF_RECORD_EXIT,
6519 .size = sizeof(task_event.event_id),
6529 perf_iterate_sb(perf_event_task_output,
6534 void perf_event_fork(struct task_struct *task)
6536 perf_event_task(task, NULL, 1);
6537 perf_event_namespaces(task);
6544 struct perf_comm_event {
6545 struct task_struct *task;
6550 struct perf_event_header header;
6557 static int perf_event_comm_match(struct perf_event *event)
6559 return event->attr.comm;
6562 static void perf_event_comm_output(struct perf_event *event,
6565 struct perf_comm_event *comm_event = data;
6566 struct perf_output_handle handle;
6567 struct perf_sample_data sample;
6568 int size = comm_event->event_id.header.size;
6571 if (!perf_event_comm_match(event))
6574 perf_event_header__init_id(&comm_event->event_id.header, &sample, event);
6575 ret = perf_output_begin(&handle, event,
6576 comm_event->event_id.header.size);
6581 comm_event->event_id.pid = perf_event_pid(event, comm_event->task);
6582 comm_event->event_id.tid = perf_event_tid(event, comm_event->task);
6584 perf_output_put(&handle, comm_event->event_id);
6585 __output_copy(&handle, comm_event->comm,
6586 comm_event->comm_size);
6588 perf_event__output_id_sample(event, &handle, &sample);
6590 perf_output_end(&handle);
6592 comm_event->event_id.header.size = size;
6595 static void perf_event_comm_event(struct perf_comm_event *comm_event)
6597 char comm[TASK_COMM_LEN];
6600 memset(comm, 0, sizeof(comm));
6601 strlcpy(comm, comm_event->task->comm, sizeof(comm));
6602 size = ALIGN(strlen(comm)+1, sizeof(u64));
6604 comm_event->comm = comm;
6605 comm_event->comm_size = size;
6607 comm_event->event_id.header.size = sizeof(comm_event->event_id) + size;
6609 perf_iterate_sb(perf_event_comm_output,
6614 void perf_event_comm(struct task_struct *task, bool exec)
6616 struct perf_comm_event comm_event;
6618 if (!atomic_read(&nr_comm_events))
6621 comm_event = (struct perf_comm_event){
6627 .type = PERF_RECORD_COMM,
6628 .misc = exec ? PERF_RECORD_MISC_COMM_EXEC : 0,
6636 perf_event_comm_event(&comm_event);
6640 * namespaces tracking
6643 struct perf_namespaces_event {
6644 struct task_struct *task;
6647 struct perf_event_header header;
6652 struct perf_ns_link_info link_info[NR_NAMESPACES];
6656 static int perf_event_namespaces_match(struct perf_event *event)
6658 return event->attr.namespaces;
6661 static void perf_event_namespaces_output(struct perf_event *event,
6664 struct perf_namespaces_event *namespaces_event = data;
6665 struct perf_output_handle handle;
6666 struct perf_sample_data sample;
6667 u16 header_size = namespaces_event->event_id.header.size;
6670 if (!perf_event_namespaces_match(event))
6673 perf_event_header__init_id(&namespaces_event->event_id.header,
6675 ret = perf_output_begin(&handle, event,
6676 namespaces_event->event_id.header.size);
6680 namespaces_event->event_id.pid = perf_event_pid(event,
6681 namespaces_event->task);
6682 namespaces_event->event_id.tid = perf_event_tid(event,
6683 namespaces_event->task);
6685 perf_output_put(&handle, namespaces_event->event_id);
6687 perf_event__output_id_sample(event, &handle, &sample);
6689 perf_output_end(&handle);
6691 namespaces_event->event_id.header.size = header_size;
6694 static void perf_fill_ns_link_info(struct perf_ns_link_info *ns_link_info,
6695 struct task_struct *task,
6696 const struct proc_ns_operations *ns_ops)
6698 struct path ns_path;
6699 struct inode *ns_inode;
6702 error = ns_get_path(&ns_path, task, ns_ops);
6704 ns_inode = ns_path.dentry->d_inode;
6705 ns_link_info->dev = new_encode_dev(ns_inode->i_sb->s_dev);
6706 ns_link_info->ino = ns_inode->i_ino;
6711 void perf_event_namespaces(struct task_struct *task)
6713 struct perf_namespaces_event namespaces_event;
6714 struct perf_ns_link_info *ns_link_info;
6716 if (!atomic_read(&nr_namespaces_events))
6719 namespaces_event = (struct perf_namespaces_event){
6723 .type = PERF_RECORD_NAMESPACES,
6725 .size = sizeof(namespaces_event.event_id),
6729 .nr_namespaces = NR_NAMESPACES,
6730 /* .link_info[NR_NAMESPACES] */
6734 ns_link_info = namespaces_event.event_id.link_info;
6736 perf_fill_ns_link_info(&ns_link_info[MNT_NS_INDEX],
6737 task, &mntns_operations);
6739 #ifdef CONFIG_USER_NS
6740 perf_fill_ns_link_info(&ns_link_info[USER_NS_INDEX],
6741 task, &userns_operations);
6743 #ifdef CONFIG_NET_NS
6744 perf_fill_ns_link_info(&ns_link_info[NET_NS_INDEX],
6745 task, &netns_operations);
6747 #ifdef CONFIG_UTS_NS
6748 perf_fill_ns_link_info(&ns_link_info[UTS_NS_INDEX],
6749 task, &utsns_operations);
6751 #ifdef CONFIG_IPC_NS
6752 perf_fill_ns_link_info(&ns_link_info[IPC_NS_INDEX],
6753 task, &ipcns_operations);
6755 #ifdef CONFIG_PID_NS
6756 perf_fill_ns_link_info(&ns_link_info[PID_NS_INDEX],
6757 task, &pidns_operations);
6759 #ifdef CONFIG_CGROUPS
6760 perf_fill_ns_link_info(&ns_link_info[CGROUP_NS_INDEX],
6761 task, &cgroupns_operations);
6764 perf_iterate_sb(perf_event_namespaces_output,
6773 struct perf_mmap_event {
6774 struct vm_area_struct *vma;
6776 const char *file_name;
6784 struct perf_event_header header;
6794 static int perf_event_mmap_match(struct perf_event *event,
6797 struct perf_mmap_event *mmap_event = data;
6798 struct vm_area_struct *vma = mmap_event->vma;
6799 int executable = vma->vm_flags & VM_EXEC;
6801 return (!executable && event->attr.mmap_data) ||
6802 (executable && (event->attr.mmap || event->attr.mmap2));
6805 static void perf_event_mmap_output(struct perf_event *event,
6808 struct perf_mmap_event *mmap_event = data;
6809 struct perf_output_handle handle;
6810 struct perf_sample_data sample;
6811 int size = mmap_event->event_id.header.size;
6814 if (!perf_event_mmap_match(event, data))
6817 if (event->attr.mmap2) {
6818 mmap_event->event_id.header.type = PERF_RECORD_MMAP2;
6819 mmap_event->event_id.header.size += sizeof(mmap_event->maj);
6820 mmap_event->event_id.header.size += sizeof(mmap_event->min);
6821 mmap_event->event_id.header.size += sizeof(mmap_event->ino);
6822 mmap_event->event_id.header.size += sizeof(mmap_event->ino_generation);
6823 mmap_event->event_id.header.size += sizeof(mmap_event->prot);
6824 mmap_event->event_id.header.size += sizeof(mmap_event->flags);
6827 perf_event_header__init_id(&mmap_event->event_id.header, &sample, event);
6828 ret = perf_output_begin(&handle, event,
6829 mmap_event->event_id.header.size);
6833 mmap_event->event_id.pid = perf_event_pid(event, current);
6834 mmap_event->event_id.tid = perf_event_tid(event, current);
6836 perf_output_put(&handle, mmap_event->event_id);
6838 if (event->attr.mmap2) {
6839 perf_output_put(&handle, mmap_event->maj);
6840 perf_output_put(&handle, mmap_event->min);
6841 perf_output_put(&handle, mmap_event->ino);
6842 perf_output_put(&handle, mmap_event->ino_generation);
6843 perf_output_put(&handle, mmap_event->prot);
6844 perf_output_put(&handle, mmap_event->flags);
6847 __output_copy(&handle, mmap_event->file_name,
6848 mmap_event->file_size);
6850 perf_event__output_id_sample(event, &handle, &sample);
6852 perf_output_end(&handle);
6854 mmap_event->event_id.header.size = size;
6857 static void perf_event_mmap_event(struct perf_mmap_event *mmap_event)
6859 struct vm_area_struct *vma = mmap_event->vma;
6860 struct file *file = vma->vm_file;
6861 int maj = 0, min = 0;
6862 u64 ino = 0, gen = 0;
6863 u32 prot = 0, flags = 0;
6869 if (vma->vm_flags & VM_READ)
6871 if (vma->vm_flags & VM_WRITE)
6873 if (vma->vm_flags & VM_EXEC)
6876 if (vma->vm_flags & VM_MAYSHARE)
6879 flags = MAP_PRIVATE;
6881 if (vma->vm_flags & VM_DENYWRITE)
6882 flags |= MAP_DENYWRITE;
6883 if (vma->vm_flags & VM_MAYEXEC)
6884 flags |= MAP_EXECUTABLE;
6885 if (vma->vm_flags & VM_LOCKED)
6886 flags |= MAP_LOCKED;
6887 if (vma->vm_flags & VM_HUGETLB)
6888 flags |= MAP_HUGETLB;
6891 struct inode *inode;
6894 buf = kmalloc(PATH_MAX, GFP_KERNEL);
6900 * d_path() works from the end of the rb backwards, so we
6901 * need to add enough zero bytes after the string to handle
6902 * the 64bit alignment we do later.
6904 name = file_path(file, buf, PATH_MAX - sizeof(u64));
6909 inode = file_inode(vma->vm_file);
6910 dev = inode->i_sb->s_dev;
6912 gen = inode->i_generation;
6918 if (vma->vm_ops && vma->vm_ops->name) {
6919 name = (char *) vma->vm_ops->name(vma);
6924 name = (char *)arch_vma_name(vma);
6928 if (vma->vm_start <= vma->vm_mm->start_brk &&
6929 vma->vm_end >= vma->vm_mm->brk) {
6933 if (vma->vm_start <= vma->vm_mm->start_stack &&
6934 vma->vm_end >= vma->vm_mm->start_stack) {
6944 strlcpy(tmp, name, sizeof(tmp));
6948 * Since our buffer works in 8 byte units we need to align our string
6949 * size to a multiple of 8. However, we must guarantee the tail end is
6950 * zero'd out to avoid leaking random bits to userspace.
6952 size = strlen(name)+1;
6953 while (!IS_ALIGNED(size, sizeof(u64)))
6954 name[size++] = '\0';
6956 mmap_event->file_name = name;
6957 mmap_event->file_size = size;
6958 mmap_event->maj = maj;
6959 mmap_event->min = min;
6960 mmap_event->ino = ino;
6961 mmap_event->ino_generation = gen;
6962 mmap_event->prot = prot;
6963 mmap_event->flags = flags;
6965 if (!(vma->vm_flags & VM_EXEC))
6966 mmap_event->event_id.header.misc |= PERF_RECORD_MISC_MMAP_DATA;
6968 mmap_event->event_id.header.size = sizeof(mmap_event->event_id) + size;
6970 perf_iterate_sb(perf_event_mmap_output,
6978 * Check whether inode and address range match filter criteria.
6980 static bool perf_addr_filter_match(struct perf_addr_filter *filter,
6981 struct file *file, unsigned long offset,
6984 if (filter->inode != file_inode(file))
6987 if (filter->offset > offset + size)
6990 if (filter->offset + filter->size < offset)
6996 static void __perf_addr_filters_adjust(struct perf_event *event, void *data)
6998 struct perf_addr_filters_head *ifh = perf_event_addr_filters(event);
6999 struct vm_area_struct *vma = data;
7000 unsigned long off = vma->vm_pgoff << PAGE_SHIFT, flags;
7001 struct file *file = vma->vm_file;
7002 struct perf_addr_filter *filter;
7003 unsigned int restart = 0, count = 0;
7005 if (!has_addr_filter(event))
7011 raw_spin_lock_irqsave(&ifh->lock, flags);
7012 list_for_each_entry(filter, &ifh->list, entry) {
7013 if (perf_addr_filter_match(filter, file, off,
7014 vma->vm_end - vma->vm_start)) {
7015 event->addr_filters_offs[count] = vma->vm_start;
7023 event->addr_filters_gen++;
7024 raw_spin_unlock_irqrestore(&ifh->lock, flags);
7027 perf_event_stop(event, 1);
7031 * Adjust all task's events' filters to the new vma
7033 static void perf_addr_filters_adjust(struct vm_area_struct *vma)
7035 struct perf_event_context *ctx;
7039 * Data tracing isn't supported yet and as such there is no need
7040 * to keep track of anything that isn't related to executable code:
7042 if (!(vma->vm_flags & VM_EXEC))
7046 for_each_task_context_nr(ctxn) {
7047 ctx = rcu_dereference(current->perf_event_ctxp[ctxn]);
7051 perf_iterate_ctx(ctx, __perf_addr_filters_adjust, vma, true);
7056 void perf_event_mmap(struct vm_area_struct *vma)
7058 struct perf_mmap_event mmap_event;
7060 if (!atomic_read(&nr_mmap_events))
7063 mmap_event = (struct perf_mmap_event){
7069 .type = PERF_RECORD_MMAP,
7070 .misc = PERF_RECORD_MISC_USER,
7075 .start = vma->vm_start,
7076 .len = vma->vm_end - vma->vm_start,
7077 .pgoff = (u64)vma->vm_pgoff << PAGE_SHIFT,
7079 /* .maj (attr_mmap2 only) */
7080 /* .min (attr_mmap2 only) */
7081 /* .ino (attr_mmap2 only) */
7082 /* .ino_generation (attr_mmap2 only) */
7083 /* .prot (attr_mmap2 only) */
7084 /* .flags (attr_mmap2 only) */
7087 perf_addr_filters_adjust(vma);
7088 perf_event_mmap_event(&mmap_event);
7091 void perf_event_aux_event(struct perf_event *event, unsigned long head,
7092 unsigned long size, u64 flags)
7094 struct perf_output_handle handle;
7095 struct perf_sample_data sample;
7096 struct perf_aux_event {
7097 struct perf_event_header header;
7103 .type = PERF_RECORD_AUX,
7105 .size = sizeof(rec),
7113 perf_event_header__init_id(&rec.header, &sample, event);
7114 ret = perf_output_begin(&handle, event, rec.header.size);
7119 perf_output_put(&handle, rec);
7120 perf_event__output_id_sample(event, &handle, &sample);
7122 perf_output_end(&handle);
7126 * Lost/dropped samples logging
7128 void perf_log_lost_samples(struct perf_event *event, u64 lost)
7130 struct perf_output_handle handle;
7131 struct perf_sample_data sample;
7135 struct perf_event_header header;
7137 } lost_samples_event = {
7139 .type = PERF_RECORD_LOST_SAMPLES,
7141 .size = sizeof(lost_samples_event),
7146 perf_event_header__init_id(&lost_samples_event.header, &sample, event);
7148 ret = perf_output_begin(&handle, event,
7149 lost_samples_event.header.size);
7153 perf_output_put(&handle, lost_samples_event);
7154 perf_event__output_id_sample(event, &handle, &sample);
7155 perf_output_end(&handle);
7159 * context_switch tracking
7162 struct perf_switch_event {
7163 struct task_struct *task;
7164 struct task_struct *next_prev;
7167 struct perf_event_header header;
7173 static int perf_event_switch_match(struct perf_event *event)
7175 return event->attr.context_switch;
7178 static void perf_event_switch_output(struct perf_event *event, void *data)
7180 struct perf_switch_event *se = data;
7181 struct perf_output_handle handle;
7182 struct perf_sample_data sample;
7185 if (!perf_event_switch_match(event))
7188 /* Only CPU-wide events are allowed to see next/prev pid/tid */
7189 if (event->ctx->task) {
7190 se->event_id.header.type = PERF_RECORD_SWITCH;
7191 se->event_id.header.size = sizeof(se->event_id.header);
7193 se->event_id.header.type = PERF_RECORD_SWITCH_CPU_WIDE;
7194 se->event_id.header.size = sizeof(se->event_id);
7195 se->event_id.next_prev_pid =
7196 perf_event_pid(event, se->next_prev);
7197 se->event_id.next_prev_tid =
7198 perf_event_tid(event, se->next_prev);
7201 perf_event_header__init_id(&se->event_id.header, &sample, event);
7203 ret = perf_output_begin(&handle, event, se->event_id.header.size);
7207 if (event->ctx->task)
7208 perf_output_put(&handle, se->event_id.header);
7210 perf_output_put(&handle, se->event_id);
7212 perf_event__output_id_sample(event, &handle, &sample);
7214 perf_output_end(&handle);
7217 static void perf_event_switch(struct task_struct *task,
7218 struct task_struct *next_prev, bool sched_in)
7220 struct perf_switch_event switch_event;
7222 /* N.B. caller checks nr_switch_events != 0 */
7224 switch_event = (struct perf_switch_event){
7226 .next_prev = next_prev,
7230 .misc = sched_in ? 0 : PERF_RECORD_MISC_SWITCH_OUT,
7233 /* .next_prev_pid */
7234 /* .next_prev_tid */
7238 perf_iterate_sb(perf_event_switch_output,
7244 * IRQ throttle logging
7247 static void perf_log_throttle(struct perf_event *event, int enable)
7249 struct perf_output_handle handle;
7250 struct perf_sample_data sample;
7254 struct perf_event_header header;
7258 } throttle_event = {
7260 .type = PERF_RECORD_THROTTLE,
7262 .size = sizeof(throttle_event),
7264 .time = perf_event_clock(event),
7265 .id = primary_event_id(event),
7266 .stream_id = event->id,
7270 throttle_event.header.type = PERF_RECORD_UNTHROTTLE;
7272 perf_event_header__init_id(&throttle_event.header, &sample, event);
7274 ret = perf_output_begin(&handle, event,
7275 throttle_event.header.size);
7279 perf_output_put(&handle, throttle_event);
7280 perf_event__output_id_sample(event, &handle, &sample);
7281 perf_output_end(&handle);
7284 void perf_event_itrace_started(struct perf_event *event)
7286 event->attach_state |= PERF_ATTACH_ITRACE;
7289 static void perf_log_itrace_start(struct perf_event *event)
7291 struct perf_output_handle handle;
7292 struct perf_sample_data sample;
7293 struct perf_aux_event {
7294 struct perf_event_header header;
7301 event = event->parent;
7303 if (!(event->pmu->capabilities & PERF_PMU_CAP_ITRACE) ||
7304 event->attach_state & PERF_ATTACH_ITRACE)
7307 rec.header.type = PERF_RECORD_ITRACE_START;
7308 rec.header.misc = 0;
7309 rec.header.size = sizeof(rec);
7310 rec.pid = perf_event_pid(event, current);
7311 rec.tid = perf_event_tid(event, current);
7313 perf_event_header__init_id(&rec.header, &sample, event);
7314 ret = perf_output_begin(&handle, event, rec.header.size);
7319 perf_output_put(&handle, rec);
7320 perf_event__output_id_sample(event, &handle, &sample);
7322 perf_output_end(&handle);
7326 __perf_event_account_interrupt(struct perf_event *event, int throttle)
7328 struct hw_perf_event *hwc = &event->hw;
7332 seq = __this_cpu_read(perf_throttled_seq);
7333 if (seq != hwc->interrupts_seq) {
7334 hwc->interrupts_seq = seq;
7335 hwc->interrupts = 1;
7338 if (unlikely(throttle
7339 && hwc->interrupts >= max_samples_per_tick)) {
7340 __this_cpu_inc(perf_throttled_count);
7341 tick_dep_set_cpu(smp_processor_id(), TICK_DEP_BIT_PERF_EVENTS);
7342 hwc->interrupts = MAX_INTERRUPTS;
7343 perf_log_throttle(event, 0);
7348 if (event->attr.freq) {
7349 u64 now = perf_clock();
7350 s64 delta = now - hwc->freq_time_stamp;
7352 hwc->freq_time_stamp = now;
7354 if (delta > 0 && delta < 2*TICK_NSEC)
7355 perf_adjust_period(event, delta, hwc->last_period, true);
7361 int perf_event_account_interrupt(struct perf_event *event)
7363 return __perf_event_account_interrupt(event, 1);
7367 * Generic event overflow handling, sampling.
7370 static int __perf_event_overflow(struct perf_event *event,
7371 int throttle, struct perf_sample_data *data,
7372 struct pt_regs *regs)
7374 int events = atomic_read(&event->event_limit);
7378 * Non-sampling counters might still use the PMI to fold short
7379 * hardware counters, ignore those.
7381 if (unlikely(!is_sampling_event(event)))
7384 ret = __perf_event_account_interrupt(event, throttle);
7387 * XXX event_limit might not quite work as expected on inherited
7391 event->pending_kill = POLL_IN;
7392 if (events && atomic_dec_and_test(&event->event_limit)) {
7394 event->pending_kill = POLL_HUP;
7396 perf_event_disable_inatomic(event);
7399 READ_ONCE(event->overflow_handler)(event, data, regs);
7401 if (*perf_event_fasync(event) && event->pending_kill) {
7402 event->pending_wakeup = 1;
7403 irq_work_queue(&event->pending);
7409 int perf_event_overflow(struct perf_event *event,
7410 struct perf_sample_data *data,
7411 struct pt_regs *regs)
7413 return __perf_event_overflow(event, 1, data, regs);
7417 * Generic software event infrastructure
7420 struct swevent_htable {
7421 struct swevent_hlist *swevent_hlist;
7422 struct mutex hlist_mutex;
7425 /* Recursion avoidance in each contexts */
7426 int recursion[PERF_NR_CONTEXTS];
7429 static DEFINE_PER_CPU(struct swevent_htable, swevent_htable);
7432 * We directly increment event->count and keep a second value in
7433 * event->hw.period_left to count intervals. This period event
7434 * is kept in the range [-sample_period, 0] so that we can use the
7438 u64 perf_swevent_set_period(struct perf_event *event)
7440 struct hw_perf_event *hwc = &event->hw;
7441 u64 period = hwc->last_period;
7445 hwc->last_period = hwc->sample_period;
7448 old = val = local64_read(&hwc->period_left);
7452 nr = div64_u64(period + val, period);
7453 offset = nr * period;
7455 if (local64_cmpxchg(&hwc->period_left, old, val) != old)
7461 static void perf_swevent_overflow(struct perf_event *event, u64 overflow,
7462 struct perf_sample_data *data,
7463 struct pt_regs *regs)
7465 struct hw_perf_event *hwc = &event->hw;
7469 overflow = perf_swevent_set_period(event);
7471 if (hwc->interrupts == MAX_INTERRUPTS)
7474 for (; overflow; overflow--) {
7475 if (__perf_event_overflow(event, throttle,
7478 * We inhibit the overflow from happening when
7479 * hwc->interrupts == MAX_INTERRUPTS.
7487 static void perf_swevent_event(struct perf_event *event, u64 nr,
7488 struct perf_sample_data *data,
7489 struct pt_regs *regs)
7491 struct hw_perf_event *hwc = &event->hw;
7493 local64_add(nr, &event->count);
7498 if (!is_sampling_event(event))
7501 if ((event->attr.sample_type & PERF_SAMPLE_PERIOD) && !event->attr.freq) {
7503 return perf_swevent_overflow(event, 1, data, regs);
7505 data->period = event->hw.last_period;
7507 if (nr == 1 && hwc->sample_period == 1 && !event->attr.freq)
7508 return perf_swevent_overflow(event, 1, data, regs);
7510 if (local64_add_negative(nr, &hwc->period_left))
7513 perf_swevent_overflow(event, 0, data, regs);
7516 static int perf_exclude_event(struct perf_event *event,
7517 struct pt_regs *regs)
7519 if (event->hw.state & PERF_HES_STOPPED)
7523 if (event->attr.exclude_user && user_mode(regs))
7526 if (event->attr.exclude_kernel && !user_mode(regs))
7533 static int perf_swevent_match(struct perf_event *event,
7534 enum perf_type_id type,
7536 struct perf_sample_data *data,
7537 struct pt_regs *regs)
7539 if (event->attr.type != type)
7542 if (event->attr.config != event_id)
7545 if (perf_exclude_event(event, regs))
7551 static inline u64 swevent_hash(u64 type, u32 event_id)
7553 u64 val = event_id | (type << 32);
7555 return hash_64(val, SWEVENT_HLIST_BITS);
7558 static inline struct hlist_head *
7559 __find_swevent_head(struct swevent_hlist *hlist, u64 type, u32 event_id)
7561 u64 hash = swevent_hash(type, event_id);
7563 return &hlist->heads[hash];
7566 /* For the read side: events when they trigger */
7567 static inline struct hlist_head *
7568 find_swevent_head_rcu(struct swevent_htable *swhash, u64 type, u32 event_id)
7570 struct swevent_hlist *hlist;
7572 hlist = rcu_dereference(swhash->swevent_hlist);
7576 return __find_swevent_head(hlist, type, event_id);
7579 /* For the event head insertion and removal in the hlist */
7580 static inline struct hlist_head *
7581 find_swevent_head(struct swevent_htable *swhash, struct perf_event *event)
7583 struct swevent_hlist *hlist;
7584 u32 event_id = event->attr.config;
7585 u64 type = event->attr.type;
7588 * Event scheduling is always serialized against hlist allocation
7589 * and release. Which makes the protected version suitable here.
7590 * The context lock guarantees that.
7592 hlist = rcu_dereference_protected(swhash->swevent_hlist,
7593 lockdep_is_held(&event->ctx->lock));
7597 return __find_swevent_head(hlist, type, event_id);
7600 static void do_perf_sw_event(enum perf_type_id type, u32 event_id,
7602 struct perf_sample_data *data,
7603 struct pt_regs *regs)
7605 struct swevent_htable *swhash = this_cpu_ptr(&swevent_htable);
7606 struct perf_event *event;
7607 struct hlist_head *head;
7610 head = find_swevent_head_rcu(swhash, type, event_id);
7614 hlist_for_each_entry_rcu(event, head, hlist_entry) {
7615 if (perf_swevent_match(event, type, event_id, data, regs))
7616 perf_swevent_event(event, nr, data, regs);
7622 DEFINE_PER_CPU(struct pt_regs, __perf_regs[4]);
7624 int perf_swevent_get_recursion_context(void)
7626 struct swevent_htable *swhash = this_cpu_ptr(&swevent_htable);
7628 return get_recursion_context(swhash->recursion);
7630 EXPORT_SYMBOL_GPL(perf_swevent_get_recursion_context);
7632 void perf_swevent_put_recursion_context(int rctx)
7634 struct swevent_htable *swhash = this_cpu_ptr(&swevent_htable);
7636 put_recursion_context(swhash->recursion, rctx);
7639 void ___perf_sw_event(u32 event_id, u64 nr, struct pt_regs *regs, u64 addr)
7641 struct perf_sample_data data;
7643 if (WARN_ON_ONCE(!regs))
7646 perf_sample_data_init(&data, addr, 0);
7647 do_perf_sw_event(PERF_TYPE_SOFTWARE, event_id, nr, &data, regs);
7650 void __perf_sw_event(u32 event_id, u64 nr, struct pt_regs *regs, u64 addr)
7654 preempt_disable_notrace();
7655 rctx = perf_swevent_get_recursion_context();
7656 if (unlikely(rctx < 0))
7659 ___perf_sw_event(event_id, nr, regs, addr);
7661 perf_swevent_put_recursion_context(rctx);
7663 preempt_enable_notrace();
7666 static void perf_swevent_read(struct perf_event *event)
7670 static int perf_swevent_add(struct perf_event *event, int flags)
7672 struct swevent_htable *swhash = this_cpu_ptr(&swevent_htable);
7673 struct hw_perf_event *hwc = &event->hw;
7674 struct hlist_head *head;
7676 if (is_sampling_event(event)) {
7677 hwc->last_period = hwc->sample_period;
7678 perf_swevent_set_period(event);
7681 hwc->state = !(flags & PERF_EF_START);
7683 head = find_swevent_head(swhash, event);
7684 if (WARN_ON_ONCE(!head))
7687 hlist_add_head_rcu(&event->hlist_entry, head);
7688 perf_event_update_userpage(event);
7693 static void perf_swevent_del(struct perf_event *event, int flags)
7695 hlist_del_rcu(&event->hlist_entry);
7698 static void perf_swevent_start(struct perf_event *event, int flags)
7700 event->hw.state = 0;
7703 static void perf_swevent_stop(struct perf_event *event, int flags)
7705 event->hw.state = PERF_HES_STOPPED;
7708 /* Deref the hlist from the update side */
7709 static inline struct swevent_hlist *
7710 swevent_hlist_deref(struct swevent_htable *swhash)
7712 return rcu_dereference_protected(swhash->swevent_hlist,
7713 lockdep_is_held(&swhash->hlist_mutex));
7716 static void swevent_hlist_release(struct swevent_htable *swhash)
7718 struct swevent_hlist *hlist = swevent_hlist_deref(swhash);
7723 RCU_INIT_POINTER(swhash->swevent_hlist, NULL);
7724 kfree_rcu(hlist, rcu_head);
7727 static void swevent_hlist_put_cpu(int cpu)
7729 struct swevent_htable *swhash = &per_cpu(swevent_htable, cpu);
7731 mutex_lock(&swhash->hlist_mutex);
7733 if (!--swhash->hlist_refcount)
7734 swevent_hlist_release(swhash);
7736 mutex_unlock(&swhash->hlist_mutex);
7739 static void swevent_hlist_put(void)
7743 for_each_possible_cpu(cpu)
7744 swevent_hlist_put_cpu(cpu);
7747 static int swevent_hlist_get_cpu(int cpu)
7749 struct swevent_htable *swhash = &per_cpu(swevent_htable, cpu);
7752 mutex_lock(&swhash->hlist_mutex);
7753 if (!swevent_hlist_deref(swhash) &&
7754 cpumask_test_cpu(cpu, perf_online_mask)) {
7755 struct swevent_hlist *hlist;
7757 hlist = kzalloc(sizeof(*hlist), GFP_KERNEL);
7762 rcu_assign_pointer(swhash->swevent_hlist, hlist);
7764 swhash->hlist_refcount++;
7766 mutex_unlock(&swhash->hlist_mutex);
7771 static int swevent_hlist_get(void)
7773 int err, cpu, failed_cpu;
7775 mutex_lock(&pmus_lock);
7776 for_each_possible_cpu(cpu) {
7777 err = swevent_hlist_get_cpu(cpu);
7783 mutex_unlock(&pmus_lock);
7786 for_each_possible_cpu(cpu) {
7787 if (cpu == failed_cpu)
7789 swevent_hlist_put_cpu(cpu);
7791 mutex_unlock(&pmus_lock);
7795 struct static_key perf_swevent_enabled[PERF_COUNT_SW_MAX];
7797 static void sw_perf_event_destroy(struct perf_event *event)
7799 u64 event_id = event->attr.config;
7801 WARN_ON(event->parent);
7803 static_key_slow_dec(&perf_swevent_enabled[event_id]);
7804 swevent_hlist_put();
7807 static int perf_swevent_init(struct perf_event *event)
7809 u64 event_id = event->attr.config;
7811 if (event->attr.type != PERF_TYPE_SOFTWARE)
7815 * no branch sampling for software events
7817 if (has_branch_stack(event))
7821 case PERF_COUNT_SW_CPU_CLOCK:
7822 case PERF_COUNT_SW_TASK_CLOCK:
7829 if (event_id >= PERF_COUNT_SW_MAX)
7832 if (!event->parent) {
7835 err = swevent_hlist_get();
7839 static_key_slow_inc(&perf_swevent_enabled[event_id]);
7840 event->destroy = sw_perf_event_destroy;
7846 static struct pmu perf_swevent = {
7847 .task_ctx_nr = perf_sw_context,
7849 .capabilities = PERF_PMU_CAP_NO_NMI,
7851 .event_init = perf_swevent_init,
7852 .add = perf_swevent_add,
7853 .del = perf_swevent_del,
7854 .start = perf_swevent_start,
7855 .stop = perf_swevent_stop,
7856 .read = perf_swevent_read,
7859 #ifdef CONFIG_EVENT_TRACING
7861 static int perf_tp_filter_match(struct perf_event *event,
7862 struct perf_sample_data *data)
7864 void *record = data->raw->frag.data;
7866 /* only top level events have filters set */
7868 event = event->parent;
7870 if (likely(!event->filter) || filter_match_preds(event->filter, record))
7875 static int perf_tp_event_match(struct perf_event *event,
7876 struct perf_sample_data *data,
7877 struct pt_regs *regs)
7879 if (event->hw.state & PERF_HES_STOPPED)
7882 * All tracepoints are from kernel-space.
7884 if (event->attr.exclude_kernel)
7887 if (!perf_tp_filter_match(event, data))
7893 void perf_trace_run_bpf_submit(void *raw_data, int size, int rctx,
7894 struct trace_event_call *call, u64 count,
7895 struct pt_regs *regs, struct hlist_head *head,
7896 struct task_struct *task)
7898 if (bpf_prog_array_valid(call)) {
7899 *(struct pt_regs **)raw_data = regs;
7900 if (!trace_call_bpf(call, raw_data) || hlist_empty(head)) {
7901 perf_swevent_put_recursion_context(rctx);
7905 perf_tp_event(call->event.type, count, raw_data, size, regs, head,
7908 EXPORT_SYMBOL_GPL(perf_trace_run_bpf_submit);
7910 void perf_tp_event(u16 event_type, u64 count, void *record, int entry_size,
7911 struct pt_regs *regs, struct hlist_head *head, int rctx,
7912 struct task_struct *task)
7914 struct perf_sample_data data;
7915 struct perf_event *event;
7917 struct perf_raw_record raw = {
7924 perf_sample_data_init(&data, 0, 0);
7927 perf_trace_buf_update(record, event_type);
7929 hlist_for_each_entry_rcu(event, head, hlist_entry) {
7930 if (perf_tp_event_match(event, &data, regs))
7931 perf_swevent_event(event, count, &data, regs);
7935 * If we got specified a target task, also iterate its context and
7936 * deliver this event there too.
7938 if (task && task != current) {
7939 struct perf_event_context *ctx;
7940 struct trace_entry *entry = record;
7943 ctx = rcu_dereference(task->perf_event_ctxp[perf_sw_context]);
7947 list_for_each_entry_rcu(event, &ctx->event_list, event_entry) {
7948 if (event->attr.type != PERF_TYPE_TRACEPOINT)
7950 if (event->attr.config != entry->type)
7952 if (perf_tp_event_match(event, &data, regs))
7953 perf_swevent_event(event, count, &data, regs);
7959 perf_swevent_put_recursion_context(rctx);
7961 EXPORT_SYMBOL_GPL(perf_tp_event);
7963 static void tp_perf_event_destroy(struct perf_event *event)
7965 perf_trace_destroy(event);
7968 static int perf_tp_event_init(struct perf_event *event)
7972 if (event->attr.type != PERF_TYPE_TRACEPOINT)
7976 * no branch sampling for tracepoint events
7978 if (has_branch_stack(event))
7981 err = perf_trace_init(event);
7985 event->destroy = tp_perf_event_destroy;
7990 static struct pmu perf_tracepoint = {
7991 .task_ctx_nr = perf_sw_context,
7993 .event_init = perf_tp_event_init,
7994 .add = perf_trace_add,
7995 .del = perf_trace_del,
7996 .start = perf_swevent_start,
7997 .stop = perf_swevent_stop,
7998 .read = perf_swevent_read,
8001 static inline void perf_tp_register(void)
8003 perf_pmu_register(&perf_tracepoint, "tracepoint", PERF_TYPE_TRACEPOINT);
8006 static void perf_event_free_filter(struct perf_event *event)
8008 ftrace_profile_free_filter(event);
8011 #ifdef CONFIG_BPF_SYSCALL
8012 static void bpf_overflow_handler(struct perf_event *event,
8013 struct perf_sample_data *data,
8014 struct pt_regs *regs)
8016 struct bpf_perf_event_data_kern ctx = {
8022 ctx.regs = perf_arch_bpf_user_pt_regs(regs);
8024 if (unlikely(__this_cpu_inc_return(bpf_prog_active) != 1))
8027 ret = BPF_PROG_RUN(event->prog, &ctx);
8030 __this_cpu_dec(bpf_prog_active);
8035 event->orig_overflow_handler(event, data, regs);
8038 static int perf_event_set_bpf_handler(struct perf_event *event, u32 prog_fd)
8040 struct bpf_prog *prog;
8042 if (event->overflow_handler_context)
8043 /* hw breakpoint or kernel counter */
8049 prog = bpf_prog_get_type(prog_fd, BPF_PROG_TYPE_PERF_EVENT);
8051 return PTR_ERR(prog);
8054 event->orig_overflow_handler = READ_ONCE(event->overflow_handler);
8055 WRITE_ONCE(event->overflow_handler, bpf_overflow_handler);
8059 static void perf_event_free_bpf_handler(struct perf_event *event)
8061 struct bpf_prog *prog = event->prog;
8066 WRITE_ONCE(event->overflow_handler, event->orig_overflow_handler);
8071 static int perf_event_set_bpf_handler(struct perf_event *event, u32 prog_fd)
8075 static void perf_event_free_bpf_handler(struct perf_event *event)
8080 static int perf_event_set_bpf_prog(struct perf_event *event, u32 prog_fd)
8082 bool is_kprobe, is_tracepoint, is_syscall_tp;
8083 struct bpf_prog *prog;
8086 if (event->attr.type != PERF_TYPE_TRACEPOINT)
8087 return perf_event_set_bpf_handler(event, prog_fd);
8089 is_kprobe = event->tp_event->flags & TRACE_EVENT_FL_UKPROBE;
8090 is_tracepoint = event->tp_event->flags & TRACE_EVENT_FL_TRACEPOINT;
8091 is_syscall_tp = is_syscall_trace_event(event->tp_event);
8092 if (!is_kprobe && !is_tracepoint && !is_syscall_tp)
8093 /* bpf programs can only be attached to u/kprobe or tracepoint */
8096 prog = bpf_prog_get(prog_fd);
8098 return PTR_ERR(prog);
8100 if ((is_kprobe && prog->type != BPF_PROG_TYPE_KPROBE) ||
8101 (is_tracepoint && prog->type != BPF_PROG_TYPE_TRACEPOINT) ||
8102 (is_syscall_tp && prog->type != BPF_PROG_TYPE_TRACEPOINT)) {
8103 /* valid fd, but invalid bpf program type */
8108 /* Kprobe override only works for kprobes, not uprobes. */
8109 if (prog->kprobe_override &&
8110 !(event->tp_event->flags & TRACE_EVENT_FL_KPROBE)) {
8115 if (is_tracepoint || is_syscall_tp) {
8116 int off = trace_event_get_offsets(event->tp_event);
8118 if (prog->aux->max_ctx_offset > off) {
8124 ret = perf_event_attach_bpf_prog(event, prog);
8130 static void perf_event_free_bpf_prog(struct perf_event *event)
8132 if (event->attr.type != PERF_TYPE_TRACEPOINT) {
8133 perf_event_free_bpf_handler(event);
8136 perf_event_detach_bpf_prog(event);
8141 static inline void perf_tp_register(void)
8145 static void perf_event_free_filter(struct perf_event *event)
8149 static int perf_event_set_bpf_prog(struct perf_event *event, u32 prog_fd)
8154 static void perf_event_free_bpf_prog(struct perf_event *event)
8157 #endif /* CONFIG_EVENT_TRACING */
8159 #ifdef CONFIG_HAVE_HW_BREAKPOINT
8160 void perf_bp_event(struct perf_event *bp, void *data)
8162 struct perf_sample_data sample;
8163 struct pt_regs *regs = data;
8165 perf_sample_data_init(&sample, bp->attr.bp_addr, 0);
8167 if (!bp->hw.state && !perf_exclude_event(bp, regs))
8168 perf_swevent_event(bp, 1, &sample, regs);
8173 * Allocate a new address filter
8175 static struct perf_addr_filter *
8176 perf_addr_filter_new(struct perf_event *event, struct list_head *filters)
8178 int node = cpu_to_node(event->cpu == -1 ? 0 : event->cpu);
8179 struct perf_addr_filter *filter;
8181 filter = kzalloc_node(sizeof(*filter), GFP_KERNEL, node);
8185 INIT_LIST_HEAD(&filter->entry);
8186 list_add_tail(&filter->entry, filters);
8191 static void free_filters_list(struct list_head *filters)
8193 struct perf_addr_filter *filter, *iter;
8195 list_for_each_entry_safe(filter, iter, filters, entry) {
8197 iput(filter->inode);
8198 list_del(&filter->entry);
8204 * Free existing address filters and optionally install new ones
8206 static void perf_addr_filters_splice(struct perf_event *event,
8207 struct list_head *head)
8209 unsigned long flags;
8212 if (!has_addr_filter(event))
8215 /* don't bother with children, they don't have their own filters */
8219 raw_spin_lock_irqsave(&event->addr_filters.lock, flags);
8221 list_splice_init(&event->addr_filters.list, &list);
8223 list_splice(head, &event->addr_filters.list);
8225 raw_spin_unlock_irqrestore(&event->addr_filters.lock, flags);
8227 free_filters_list(&list);
8231 * Scan through mm's vmas and see if one of them matches the
8232 * @filter; if so, adjust filter's address range.
8233 * Called with mm::mmap_sem down for reading.
8235 static unsigned long perf_addr_filter_apply(struct perf_addr_filter *filter,
8236 struct mm_struct *mm)
8238 struct vm_area_struct *vma;
8240 for (vma = mm->mmap; vma; vma = vma->vm_next) {
8241 struct file *file = vma->vm_file;
8242 unsigned long off = vma->vm_pgoff << PAGE_SHIFT;
8243 unsigned long vma_size = vma->vm_end - vma->vm_start;
8248 if (!perf_addr_filter_match(filter, file, off, vma_size))
8251 return vma->vm_start;
8258 * Update event's address range filters based on the
8259 * task's existing mappings, if any.
8261 static void perf_event_addr_filters_apply(struct perf_event *event)
8263 struct perf_addr_filters_head *ifh = perf_event_addr_filters(event);
8264 struct task_struct *task = READ_ONCE(event->ctx->task);
8265 struct perf_addr_filter *filter;
8266 struct mm_struct *mm = NULL;
8267 unsigned int count = 0;
8268 unsigned long flags;
8271 * We may observe TASK_TOMBSTONE, which means that the event tear-down
8272 * will stop on the parent's child_mutex that our caller is also holding
8274 if (task == TASK_TOMBSTONE)
8277 if (!ifh->nr_file_filters)
8280 mm = get_task_mm(event->ctx->task);
8284 down_read(&mm->mmap_sem);
8286 raw_spin_lock_irqsave(&ifh->lock, flags);
8287 list_for_each_entry(filter, &ifh->list, entry) {
8288 event->addr_filters_offs[count] = 0;
8291 * Adjust base offset if the filter is associated to a binary
8292 * that needs to be mapped:
8295 event->addr_filters_offs[count] =
8296 perf_addr_filter_apply(filter, mm);
8301 event->addr_filters_gen++;
8302 raw_spin_unlock_irqrestore(&ifh->lock, flags);
8304 up_read(&mm->mmap_sem);
8309 perf_event_stop(event, 1);
8313 * Address range filtering: limiting the data to certain
8314 * instruction address ranges. Filters are ioctl()ed to us from
8315 * userspace as ascii strings.
8317 * Filter string format:
8320 * where ACTION is one of the
8321 * * "filter": limit the trace to this region
8322 * * "start": start tracing from this address
8323 * * "stop": stop tracing at this address/region;
8325 * * for kernel addresses: <start address>[/<size>]
8326 * * for object files: <start address>[/<size>]@</path/to/object/file>
8328 * if <size> is not specified, the range is treated as a single address.
8342 IF_STATE_ACTION = 0,
8347 static const match_table_t if_tokens = {
8348 { IF_ACT_FILTER, "filter" },
8349 { IF_ACT_START, "start" },
8350 { IF_ACT_STOP, "stop" },
8351 { IF_SRC_FILE, "%u/%u@%s" },
8352 { IF_SRC_KERNEL, "%u/%u" },
8353 { IF_SRC_FILEADDR, "%u@%s" },
8354 { IF_SRC_KERNELADDR, "%u" },
8355 { IF_ACT_NONE, NULL },
8359 * Address filter string parser
8362 perf_event_parse_addr_filter(struct perf_event *event, char *fstr,
8363 struct list_head *filters)
8365 struct perf_addr_filter *filter = NULL;
8366 char *start, *orig, *filename = NULL;
8368 substring_t args[MAX_OPT_ARGS];
8369 int state = IF_STATE_ACTION, token;
8370 unsigned int kernel = 0;
8373 orig = fstr = kstrdup(fstr, GFP_KERNEL);
8377 while ((start = strsep(&fstr, " ,\n")) != NULL) {
8383 /* filter definition begins */
8384 if (state == IF_STATE_ACTION) {
8385 filter = perf_addr_filter_new(event, filters);
8390 token = match_token(start, if_tokens, args);
8397 if (state != IF_STATE_ACTION)
8400 state = IF_STATE_SOURCE;
8403 case IF_SRC_KERNELADDR:
8407 case IF_SRC_FILEADDR:
8409 if (state != IF_STATE_SOURCE)
8412 if (token == IF_SRC_FILE || token == IF_SRC_KERNEL)
8416 ret = kstrtoul(args[0].from, 0, &filter->offset);
8420 if (filter->range) {
8422 ret = kstrtoul(args[1].from, 0, &filter->size);
8427 if (token == IF_SRC_FILE || token == IF_SRC_FILEADDR) {
8428 int fpos = filter->range ? 2 : 1;
8430 filename = match_strdup(&args[fpos]);
8437 state = IF_STATE_END;
8445 * Filter definition is fully parsed, validate and install it.
8446 * Make sure that it doesn't contradict itself or the event's
8449 if (state == IF_STATE_END) {
8451 if (kernel && event->attr.exclude_kernel)
8459 * For now, we only support file-based filters
8460 * in per-task events; doing so for CPU-wide
8461 * events requires additional context switching
8462 * trickery, since same object code will be
8463 * mapped at different virtual addresses in
8464 * different processes.
8467 if (!event->ctx->task)
8468 goto fail_free_name;
8470 /* look up the path and grab its inode */
8471 ret = kern_path(filename, LOOKUP_FOLLOW, &path);
8473 goto fail_free_name;
8475 filter->inode = igrab(d_inode(path.dentry));
8481 if (!filter->inode ||
8482 !S_ISREG(filter->inode->i_mode))
8483 /* free_filters_list() will iput() */
8486 event->addr_filters.nr_file_filters++;
8489 /* ready to consume more filters */
8490 state = IF_STATE_ACTION;
8495 if (state != IF_STATE_ACTION)
8505 free_filters_list(filters);
8512 perf_event_set_addr_filter(struct perf_event *event, char *filter_str)
8518 * Since this is called in perf_ioctl() path, we're already holding
8521 lockdep_assert_held(&event->ctx->mutex);
8523 if (WARN_ON_ONCE(event->parent))
8526 ret = perf_event_parse_addr_filter(event, filter_str, &filters);
8528 goto fail_clear_files;
8530 ret = event->pmu->addr_filters_validate(&filters);
8532 goto fail_free_filters;
8534 /* remove existing filters, if any */
8535 perf_addr_filters_splice(event, &filters);
8537 /* install new filters */
8538 perf_event_for_each_child(event, perf_event_addr_filters_apply);
8543 free_filters_list(&filters);
8546 event->addr_filters.nr_file_filters = 0;
8552 perf_tracepoint_set_filter(struct perf_event *event, char *filter_str)
8554 struct perf_event_context *ctx = event->ctx;
8558 * Beware, here be dragons!!
8560 * the tracepoint muck will deadlock against ctx->mutex, but the tracepoint
8561 * stuff does not actually need it. So temporarily drop ctx->mutex. As per
8562 * perf_event_ctx_lock() we already have a reference on ctx.
8564 * This can result in event getting moved to a different ctx, but that
8565 * does not affect the tracepoint state.
8567 mutex_unlock(&ctx->mutex);
8568 ret = ftrace_profile_set_filter(event, event->attr.config, filter_str);
8569 mutex_lock(&ctx->mutex);
8574 static int perf_event_set_filter(struct perf_event *event, void __user *arg)
8579 if ((event->attr.type != PERF_TYPE_TRACEPOINT ||
8580 !IS_ENABLED(CONFIG_EVENT_TRACING)) &&
8581 !has_addr_filter(event))
8584 filter_str = strndup_user(arg, PAGE_SIZE);
8585 if (IS_ERR(filter_str))
8586 return PTR_ERR(filter_str);
8588 if (IS_ENABLED(CONFIG_EVENT_TRACING) &&
8589 event->attr.type == PERF_TYPE_TRACEPOINT)
8590 ret = perf_tracepoint_set_filter(event, filter_str);
8591 else if (has_addr_filter(event))
8592 ret = perf_event_set_addr_filter(event, filter_str);
8599 * hrtimer based swevent callback
8602 static enum hrtimer_restart perf_swevent_hrtimer(struct hrtimer *hrtimer)
8604 enum hrtimer_restart ret = HRTIMER_RESTART;
8605 struct perf_sample_data data;
8606 struct pt_regs *regs;
8607 struct perf_event *event;
8610 event = container_of(hrtimer, struct perf_event, hw.hrtimer);
8612 if (event->state != PERF_EVENT_STATE_ACTIVE)
8613 return HRTIMER_NORESTART;
8615 event->pmu->read(event);
8617 perf_sample_data_init(&data, 0, event->hw.last_period);
8618 regs = get_irq_regs();
8620 if (regs && !perf_exclude_event(event, regs)) {
8621 if (!(event->attr.exclude_idle && is_idle_task(current)))
8622 if (__perf_event_overflow(event, 1, &data, regs))
8623 ret = HRTIMER_NORESTART;
8626 period = max_t(u64, 10000, event->hw.sample_period);
8627 hrtimer_forward_now(hrtimer, ns_to_ktime(period));
8632 static void perf_swevent_start_hrtimer(struct perf_event *event)
8634 struct hw_perf_event *hwc = &event->hw;
8637 if (!is_sampling_event(event))
8640 period = local64_read(&hwc->period_left);
8645 local64_set(&hwc->period_left, 0);
8647 period = max_t(u64, 10000, hwc->sample_period);
8649 hrtimer_start(&hwc->hrtimer, ns_to_ktime(period),
8650 HRTIMER_MODE_REL_PINNED);
8653 static void perf_swevent_cancel_hrtimer(struct perf_event *event)
8655 struct hw_perf_event *hwc = &event->hw;
8657 if (is_sampling_event(event)) {
8658 ktime_t remaining = hrtimer_get_remaining(&hwc->hrtimer);
8659 local64_set(&hwc->period_left, ktime_to_ns(remaining));
8661 hrtimer_cancel(&hwc->hrtimer);
8665 static void perf_swevent_init_hrtimer(struct perf_event *event)
8667 struct hw_perf_event *hwc = &event->hw;
8669 if (!is_sampling_event(event))
8672 hrtimer_init(&hwc->hrtimer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
8673 hwc->hrtimer.function = perf_swevent_hrtimer;
8676 * Since hrtimers have a fixed rate, we can do a static freq->period
8677 * mapping and avoid the whole period adjust feedback stuff.
8679 if (event->attr.freq) {
8680 long freq = event->attr.sample_freq;
8682 event->attr.sample_period = NSEC_PER_SEC / freq;
8683 hwc->sample_period = event->attr.sample_period;
8684 local64_set(&hwc->period_left, hwc->sample_period);
8685 hwc->last_period = hwc->sample_period;
8686 event->attr.freq = 0;
8691 * Software event: cpu wall time clock
8694 static void cpu_clock_event_update(struct perf_event *event)
8699 now = local_clock();
8700 prev = local64_xchg(&event->hw.prev_count, now);
8701 local64_add(now - prev, &event->count);
8704 static void cpu_clock_event_start(struct perf_event *event, int flags)
8706 local64_set(&event->hw.prev_count, local_clock());
8707 perf_swevent_start_hrtimer(event);
8710 static void cpu_clock_event_stop(struct perf_event *event, int flags)
8712 perf_swevent_cancel_hrtimer(event);
8713 cpu_clock_event_update(event);
8716 static int cpu_clock_event_add(struct perf_event *event, int flags)
8718 if (flags & PERF_EF_START)
8719 cpu_clock_event_start(event, flags);
8720 perf_event_update_userpage(event);
8725 static void cpu_clock_event_del(struct perf_event *event, int flags)
8727 cpu_clock_event_stop(event, flags);
8730 static void cpu_clock_event_read(struct perf_event *event)
8732 cpu_clock_event_update(event);
8735 static int cpu_clock_event_init(struct perf_event *event)
8737 if (event->attr.type != PERF_TYPE_SOFTWARE)
8740 if (event->attr.config != PERF_COUNT_SW_CPU_CLOCK)
8744 * no branch sampling for software events
8746 if (has_branch_stack(event))
8749 perf_swevent_init_hrtimer(event);
8754 static struct pmu perf_cpu_clock = {
8755 .task_ctx_nr = perf_sw_context,
8757 .capabilities = PERF_PMU_CAP_NO_NMI,
8759 .event_init = cpu_clock_event_init,
8760 .add = cpu_clock_event_add,
8761 .del = cpu_clock_event_del,
8762 .start = cpu_clock_event_start,
8763 .stop = cpu_clock_event_stop,
8764 .read = cpu_clock_event_read,
8768 * Software event: task time clock
8771 static void task_clock_event_update(struct perf_event *event, u64 now)
8776 prev = local64_xchg(&event->hw.prev_count, now);
8778 local64_add(delta, &event->count);
8781 static void task_clock_event_start(struct perf_event *event, int flags)
8783 local64_set(&event->hw.prev_count, event->ctx->time);
8784 perf_swevent_start_hrtimer(event);
8787 static void task_clock_event_stop(struct perf_event *event, int flags)
8789 perf_swevent_cancel_hrtimer(event);
8790 task_clock_event_update(event, event->ctx->time);
8793 static int task_clock_event_add(struct perf_event *event, int flags)
8795 if (flags & PERF_EF_START)
8796 task_clock_event_start(event, flags);
8797 perf_event_update_userpage(event);
8802 static void task_clock_event_del(struct perf_event *event, int flags)
8804 task_clock_event_stop(event, PERF_EF_UPDATE);
8807 static void task_clock_event_read(struct perf_event *event)
8809 u64 now = perf_clock();
8810 u64 delta = now - event->ctx->timestamp;
8811 u64 time = event->ctx->time + delta;
8813 task_clock_event_update(event, time);
8816 static int task_clock_event_init(struct perf_event *event)
8818 if (event->attr.type != PERF_TYPE_SOFTWARE)
8821 if (event->attr.config != PERF_COUNT_SW_TASK_CLOCK)
8825 * no branch sampling for software events
8827 if (has_branch_stack(event))
8830 perf_swevent_init_hrtimer(event);
8835 static struct pmu perf_task_clock = {
8836 .task_ctx_nr = perf_sw_context,
8838 .capabilities = PERF_PMU_CAP_NO_NMI,
8840 .event_init = task_clock_event_init,
8841 .add = task_clock_event_add,
8842 .del = task_clock_event_del,
8843 .start = task_clock_event_start,
8844 .stop = task_clock_event_stop,
8845 .read = task_clock_event_read,
8848 static void perf_pmu_nop_void(struct pmu *pmu)
8852 static void perf_pmu_nop_txn(struct pmu *pmu, unsigned int flags)
8856 static int perf_pmu_nop_int(struct pmu *pmu)
8861 static DEFINE_PER_CPU(unsigned int, nop_txn_flags);
8863 static void perf_pmu_start_txn(struct pmu *pmu, unsigned int flags)
8865 __this_cpu_write(nop_txn_flags, flags);
8867 if (flags & ~PERF_PMU_TXN_ADD)
8870 perf_pmu_disable(pmu);
8873 static int perf_pmu_commit_txn(struct pmu *pmu)
8875 unsigned int flags = __this_cpu_read(nop_txn_flags);
8877 __this_cpu_write(nop_txn_flags, 0);
8879 if (flags & ~PERF_PMU_TXN_ADD)
8882 perf_pmu_enable(pmu);
8886 static void perf_pmu_cancel_txn(struct pmu *pmu)
8888 unsigned int flags = __this_cpu_read(nop_txn_flags);
8890 __this_cpu_write(nop_txn_flags, 0);
8892 if (flags & ~PERF_PMU_TXN_ADD)
8895 perf_pmu_enable(pmu);
8898 static int perf_event_idx_default(struct perf_event *event)
8904 * Ensures all contexts with the same task_ctx_nr have the same
8905 * pmu_cpu_context too.
8907 static struct perf_cpu_context __percpu *find_pmu_context(int ctxn)
8914 list_for_each_entry(pmu, &pmus, entry) {
8915 if (pmu->task_ctx_nr == ctxn)
8916 return pmu->pmu_cpu_context;
8922 static void free_pmu_context(struct pmu *pmu)
8925 * Static contexts such as perf_sw_context have a global lifetime
8926 * and may be shared between different PMUs. Avoid freeing them
8927 * when a single PMU is going away.
8929 if (pmu->task_ctx_nr > perf_invalid_context)
8932 mutex_lock(&pmus_lock);
8933 free_percpu(pmu->pmu_cpu_context);
8934 mutex_unlock(&pmus_lock);
8938 * Let userspace know that this PMU supports address range filtering:
8940 static ssize_t nr_addr_filters_show(struct device *dev,
8941 struct device_attribute *attr,
8944 struct pmu *pmu = dev_get_drvdata(dev);
8946 return snprintf(page, PAGE_SIZE - 1, "%d\n", pmu->nr_addr_filters);
8948 DEVICE_ATTR_RO(nr_addr_filters);
8950 static struct idr pmu_idr;
8953 type_show(struct device *dev, struct device_attribute *attr, char *page)
8955 struct pmu *pmu = dev_get_drvdata(dev);
8957 return snprintf(page, PAGE_SIZE-1, "%d\n", pmu->type);
8959 static DEVICE_ATTR_RO(type);
8962 perf_event_mux_interval_ms_show(struct device *dev,
8963 struct device_attribute *attr,
8966 struct pmu *pmu = dev_get_drvdata(dev);
8968 return snprintf(page, PAGE_SIZE-1, "%d\n", pmu->hrtimer_interval_ms);
8971 static DEFINE_MUTEX(mux_interval_mutex);
8974 perf_event_mux_interval_ms_store(struct device *dev,
8975 struct device_attribute *attr,
8976 const char *buf, size_t count)
8978 struct pmu *pmu = dev_get_drvdata(dev);
8979 int timer, cpu, ret;
8981 ret = kstrtoint(buf, 0, &timer);
8988 /* same value, noting to do */
8989 if (timer == pmu->hrtimer_interval_ms)
8992 mutex_lock(&mux_interval_mutex);
8993 pmu->hrtimer_interval_ms = timer;
8995 /* update all cpuctx for this PMU */
8997 for_each_online_cpu(cpu) {
8998 struct perf_cpu_context *cpuctx;
8999 cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
9000 cpuctx->hrtimer_interval = ns_to_ktime(NSEC_PER_MSEC * timer);
9002 cpu_function_call(cpu,
9003 (remote_function_f)perf_mux_hrtimer_restart, cpuctx);
9006 mutex_unlock(&mux_interval_mutex);
9010 static DEVICE_ATTR_RW(perf_event_mux_interval_ms);
9012 static struct attribute *pmu_dev_attrs[] = {
9013 &dev_attr_type.attr,
9014 &dev_attr_perf_event_mux_interval_ms.attr,
9017 ATTRIBUTE_GROUPS(pmu_dev);
9019 static int pmu_bus_running;
9020 static struct bus_type pmu_bus = {
9021 .name = "event_source",
9022 .dev_groups = pmu_dev_groups,
9025 static void pmu_dev_release(struct device *dev)
9030 static int pmu_dev_alloc(struct pmu *pmu)
9034 pmu->dev = kzalloc(sizeof(struct device), GFP_KERNEL);
9038 pmu->dev->groups = pmu->attr_groups;
9039 device_initialize(pmu->dev);
9040 ret = dev_set_name(pmu->dev, "%s", pmu->name);
9044 dev_set_drvdata(pmu->dev, pmu);
9045 pmu->dev->bus = &pmu_bus;
9046 pmu->dev->release = pmu_dev_release;
9047 ret = device_add(pmu->dev);
9051 /* For PMUs with address filters, throw in an extra attribute: */
9052 if (pmu->nr_addr_filters)
9053 ret = device_create_file(pmu->dev, &dev_attr_nr_addr_filters);
9062 device_del(pmu->dev);
9065 put_device(pmu->dev);
9069 static struct lock_class_key cpuctx_mutex;
9070 static struct lock_class_key cpuctx_lock;
9072 int perf_pmu_register(struct pmu *pmu, const char *name, int type)
9076 mutex_lock(&pmus_lock);
9078 pmu->pmu_disable_count = alloc_percpu(int);
9079 if (!pmu->pmu_disable_count)
9088 type = idr_alloc(&pmu_idr, pmu, PERF_TYPE_MAX, 0, GFP_KERNEL);
9096 if (pmu_bus_running) {
9097 ret = pmu_dev_alloc(pmu);
9103 if (pmu->task_ctx_nr == perf_hw_context) {
9104 static int hw_context_taken = 0;
9107 * Other than systems with heterogeneous CPUs, it never makes
9108 * sense for two PMUs to share perf_hw_context. PMUs which are
9109 * uncore must use perf_invalid_context.
9111 if (WARN_ON_ONCE(hw_context_taken &&
9112 !(pmu->capabilities & PERF_PMU_CAP_HETEROGENEOUS_CPUS)))
9113 pmu->task_ctx_nr = perf_invalid_context;
9115 hw_context_taken = 1;
9118 pmu->pmu_cpu_context = find_pmu_context(pmu->task_ctx_nr);
9119 if (pmu->pmu_cpu_context)
9120 goto got_cpu_context;
9123 pmu->pmu_cpu_context = alloc_percpu(struct perf_cpu_context);
9124 if (!pmu->pmu_cpu_context)
9127 for_each_possible_cpu(cpu) {
9128 struct perf_cpu_context *cpuctx;
9130 cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
9131 __perf_event_init_context(&cpuctx->ctx);
9132 lockdep_set_class(&cpuctx->ctx.mutex, &cpuctx_mutex);
9133 lockdep_set_class(&cpuctx->ctx.lock, &cpuctx_lock);
9134 cpuctx->ctx.pmu = pmu;
9135 cpuctx->online = cpumask_test_cpu(cpu, perf_online_mask);
9137 __perf_mux_hrtimer_init(cpuctx, cpu);
9141 if (!pmu->start_txn) {
9142 if (pmu->pmu_enable) {
9144 * If we have pmu_enable/pmu_disable calls, install
9145 * transaction stubs that use that to try and batch
9146 * hardware accesses.
9148 pmu->start_txn = perf_pmu_start_txn;
9149 pmu->commit_txn = perf_pmu_commit_txn;
9150 pmu->cancel_txn = perf_pmu_cancel_txn;
9152 pmu->start_txn = perf_pmu_nop_txn;
9153 pmu->commit_txn = perf_pmu_nop_int;
9154 pmu->cancel_txn = perf_pmu_nop_void;
9158 if (!pmu->pmu_enable) {
9159 pmu->pmu_enable = perf_pmu_nop_void;
9160 pmu->pmu_disable = perf_pmu_nop_void;
9163 if (!pmu->event_idx)
9164 pmu->event_idx = perf_event_idx_default;
9166 list_add_rcu(&pmu->entry, &pmus);
9167 atomic_set(&pmu->exclusive_cnt, 0);
9170 mutex_unlock(&pmus_lock);
9175 device_del(pmu->dev);
9176 put_device(pmu->dev);
9179 if (pmu->type >= PERF_TYPE_MAX)
9180 idr_remove(&pmu_idr, pmu->type);
9183 free_percpu(pmu->pmu_disable_count);
9186 EXPORT_SYMBOL_GPL(perf_pmu_register);
9188 void perf_pmu_unregister(struct pmu *pmu)
9192 mutex_lock(&pmus_lock);
9193 remove_device = pmu_bus_running;
9194 list_del_rcu(&pmu->entry);
9195 mutex_unlock(&pmus_lock);
9198 * We dereference the pmu list under both SRCU and regular RCU, so
9199 * synchronize against both of those.
9201 synchronize_srcu(&pmus_srcu);
9204 free_percpu(pmu->pmu_disable_count);
9205 if (pmu->type >= PERF_TYPE_MAX)
9206 idr_remove(&pmu_idr, pmu->type);
9207 if (remove_device) {
9208 if (pmu->nr_addr_filters)
9209 device_remove_file(pmu->dev, &dev_attr_nr_addr_filters);
9210 device_del(pmu->dev);
9211 put_device(pmu->dev);
9213 free_pmu_context(pmu);
9215 EXPORT_SYMBOL_GPL(perf_pmu_unregister);
9217 static int perf_try_init_event(struct pmu *pmu, struct perf_event *event)
9219 struct perf_event_context *ctx = NULL;
9222 if (!try_module_get(pmu->module))
9226 * A number of pmu->event_init() methods iterate the sibling_list to,
9227 * for example, validate if the group fits on the PMU. Therefore,
9228 * if this is a sibling event, acquire the ctx->mutex to protect
9231 if (event->group_leader != event && pmu->task_ctx_nr != perf_sw_context) {
9233 * This ctx->mutex can nest when we're called through
9234 * inheritance. See the perf_event_ctx_lock_nested() comment.
9236 ctx = perf_event_ctx_lock_nested(event->group_leader,
9237 SINGLE_DEPTH_NESTING);
9242 ret = pmu->event_init(event);
9245 perf_event_ctx_unlock(event->group_leader, ctx);
9248 module_put(pmu->module);
9253 static struct pmu *perf_init_event(struct perf_event *event)
9259 idx = srcu_read_lock(&pmus_srcu);
9261 /* Try parent's PMU first: */
9262 if (event->parent && event->parent->pmu) {
9263 pmu = event->parent->pmu;
9264 ret = perf_try_init_event(pmu, event);
9270 pmu = idr_find(&pmu_idr, event->attr.type);
9273 ret = perf_try_init_event(pmu, event);
9279 list_for_each_entry_rcu(pmu, &pmus, entry) {
9280 ret = perf_try_init_event(pmu, event);
9284 if (ret != -ENOENT) {
9289 pmu = ERR_PTR(-ENOENT);
9291 srcu_read_unlock(&pmus_srcu, idx);
9296 static void attach_sb_event(struct perf_event *event)
9298 struct pmu_event_list *pel = per_cpu_ptr(&pmu_sb_events, event->cpu);
9300 raw_spin_lock(&pel->lock);
9301 list_add_rcu(&event->sb_list, &pel->list);
9302 raw_spin_unlock(&pel->lock);
9306 * We keep a list of all !task (and therefore per-cpu) events
9307 * that need to receive side-band records.
9309 * This avoids having to scan all the various PMU per-cpu contexts
9312 static void account_pmu_sb_event(struct perf_event *event)
9314 if (is_sb_event(event))
9315 attach_sb_event(event);
9318 static void account_event_cpu(struct perf_event *event, int cpu)
9323 if (is_cgroup_event(event))
9324 atomic_inc(&per_cpu(perf_cgroup_events, cpu));
9327 /* Freq events need the tick to stay alive (see perf_event_task_tick). */
9328 static void account_freq_event_nohz(void)
9330 #ifdef CONFIG_NO_HZ_FULL
9331 /* Lock so we don't race with concurrent unaccount */
9332 spin_lock(&nr_freq_lock);
9333 if (atomic_inc_return(&nr_freq_events) == 1)
9334 tick_nohz_dep_set(TICK_DEP_BIT_PERF_EVENTS);
9335 spin_unlock(&nr_freq_lock);
9339 static void account_freq_event(void)
9341 if (tick_nohz_full_enabled())
9342 account_freq_event_nohz();
9344 atomic_inc(&nr_freq_events);
9348 static void account_event(struct perf_event *event)
9355 if (event->attach_state & PERF_ATTACH_TASK)
9357 if (event->attr.mmap || event->attr.mmap_data)
9358 atomic_inc(&nr_mmap_events);
9359 if (event->attr.comm)
9360 atomic_inc(&nr_comm_events);
9361 if (event->attr.namespaces)
9362 atomic_inc(&nr_namespaces_events);
9363 if (event->attr.task)
9364 atomic_inc(&nr_task_events);
9365 if (event->attr.freq)
9366 account_freq_event();
9367 if (event->attr.context_switch) {
9368 atomic_inc(&nr_switch_events);
9371 if (has_branch_stack(event))
9373 if (is_cgroup_event(event))
9378 * We need the mutex here because static_branch_enable()
9379 * must complete *before* the perf_sched_count increment
9382 if (atomic_inc_not_zero(&perf_sched_count))
9385 mutex_lock(&perf_sched_mutex);
9386 if (!atomic_read(&perf_sched_count)) {
9387 static_branch_enable(&perf_sched_events);
9389 * Guarantee that all CPUs observe they key change and
9390 * call the perf scheduling hooks before proceeding to
9391 * install events that need them.
9393 synchronize_sched();
9396 * Now that we have waited for the sync_sched(), allow further
9397 * increments to by-pass the mutex.
9399 atomic_inc(&perf_sched_count);
9400 mutex_unlock(&perf_sched_mutex);
9404 account_event_cpu(event, event->cpu);
9406 account_pmu_sb_event(event);
9410 * Allocate and initialize a event structure
9412 static struct perf_event *
9413 perf_event_alloc(struct perf_event_attr *attr, int cpu,
9414 struct task_struct *task,
9415 struct perf_event *group_leader,
9416 struct perf_event *parent_event,
9417 perf_overflow_handler_t overflow_handler,
9418 void *context, int cgroup_fd)
9421 struct perf_event *event;
9422 struct hw_perf_event *hwc;
9425 if ((unsigned)cpu >= nr_cpu_ids) {
9426 if (!task || cpu != -1)
9427 return ERR_PTR(-EINVAL);
9430 event = kzalloc(sizeof(*event), GFP_KERNEL);
9432 return ERR_PTR(-ENOMEM);
9435 * Single events are their own group leaders, with an
9436 * empty sibling list:
9439 group_leader = event;
9441 mutex_init(&event->child_mutex);
9442 INIT_LIST_HEAD(&event->child_list);
9444 INIT_LIST_HEAD(&event->group_entry);
9445 INIT_LIST_HEAD(&event->event_entry);
9446 INIT_LIST_HEAD(&event->sibling_list);
9447 INIT_LIST_HEAD(&event->rb_entry);
9448 INIT_LIST_HEAD(&event->active_entry);
9449 INIT_LIST_HEAD(&event->addr_filters.list);
9450 INIT_HLIST_NODE(&event->hlist_entry);
9453 init_waitqueue_head(&event->waitq);
9454 init_irq_work(&event->pending, perf_pending_event);
9456 mutex_init(&event->mmap_mutex);
9457 raw_spin_lock_init(&event->addr_filters.lock);
9459 atomic_long_set(&event->refcount, 1);
9461 event->attr = *attr;
9462 event->group_leader = group_leader;
9466 event->parent = parent_event;
9468 event->ns = get_pid_ns(task_active_pid_ns(current));
9469 event->id = atomic64_inc_return(&perf_event_id);
9471 event->state = PERF_EVENT_STATE_INACTIVE;
9474 event->attach_state = PERF_ATTACH_TASK;
9476 * XXX pmu::event_init needs to know what task to account to
9477 * and we cannot use the ctx information because we need the
9478 * pmu before we get a ctx.
9480 event->hw.target = task;
9483 event->clock = &local_clock;
9485 event->clock = parent_event->clock;
9487 if (!overflow_handler && parent_event) {
9488 overflow_handler = parent_event->overflow_handler;
9489 context = parent_event->overflow_handler_context;
9490 #if defined(CONFIG_BPF_SYSCALL) && defined(CONFIG_EVENT_TRACING)
9491 if (overflow_handler == bpf_overflow_handler) {
9492 struct bpf_prog *prog = bpf_prog_inc(parent_event->prog);
9495 err = PTR_ERR(prog);
9499 event->orig_overflow_handler =
9500 parent_event->orig_overflow_handler;
9505 if (overflow_handler) {
9506 event->overflow_handler = overflow_handler;
9507 event->overflow_handler_context = context;
9508 } else if (is_write_backward(event)){
9509 event->overflow_handler = perf_event_output_backward;
9510 event->overflow_handler_context = NULL;
9512 event->overflow_handler = perf_event_output_forward;
9513 event->overflow_handler_context = NULL;
9516 perf_event__state_init(event);
9521 hwc->sample_period = attr->sample_period;
9522 if (attr->freq && attr->sample_freq)
9523 hwc->sample_period = 1;
9524 hwc->last_period = hwc->sample_period;
9526 local64_set(&hwc->period_left, hwc->sample_period);
9529 * We currently do not support PERF_SAMPLE_READ on inherited events.
9530 * See perf_output_read().
9532 if (attr->inherit && (attr->sample_type & PERF_SAMPLE_READ))
9535 if (!has_branch_stack(event))
9536 event->attr.branch_sample_type = 0;
9538 if (cgroup_fd != -1) {
9539 err = perf_cgroup_connect(cgroup_fd, event, attr, group_leader);
9544 pmu = perf_init_event(event);
9550 err = exclusive_event_init(event);
9554 if (has_addr_filter(event)) {
9555 event->addr_filters_offs = kcalloc(pmu->nr_addr_filters,
9556 sizeof(unsigned long),
9558 if (!event->addr_filters_offs) {
9563 /* force hw sync on the address filters */
9564 event->addr_filters_gen = 1;
9567 if (!event->parent) {
9568 if (event->attr.sample_type & PERF_SAMPLE_CALLCHAIN) {
9569 err = get_callchain_buffers(attr->sample_max_stack);
9571 goto err_addr_filters;
9575 /* symmetric to unaccount_event() in _free_event() */
9576 account_event(event);
9581 kfree(event->addr_filters_offs);
9584 exclusive_event_destroy(event);
9588 event->destroy(event);
9589 module_put(pmu->module);
9591 if (is_cgroup_event(event))
9592 perf_detach_cgroup(event);
9594 put_pid_ns(event->ns);
9597 return ERR_PTR(err);
9600 static int perf_copy_attr(struct perf_event_attr __user *uattr,
9601 struct perf_event_attr *attr)
9606 if (!access_ok(VERIFY_WRITE, uattr, PERF_ATTR_SIZE_VER0))
9610 * zero the full structure, so that a short copy will be nice.
9612 memset(attr, 0, sizeof(*attr));
9614 ret = get_user(size, &uattr->size);
9618 if (size > PAGE_SIZE) /* silly large */
9621 if (!size) /* abi compat */
9622 size = PERF_ATTR_SIZE_VER0;
9624 if (size < PERF_ATTR_SIZE_VER0)
9628 * If we're handed a bigger struct than we know of,
9629 * ensure all the unknown bits are 0 - i.e. new
9630 * user-space does not rely on any kernel feature
9631 * extensions we dont know about yet.
9633 if (size > sizeof(*attr)) {
9634 unsigned char __user *addr;
9635 unsigned char __user *end;
9638 addr = (void __user *)uattr + sizeof(*attr);
9639 end = (void __user *)uattr + size;
9641 for (; addr < end; addr++) {
9642 ret = get_user(val, addr);
9648 size = sizeof(*attr);
9651 ret = copy_from_user(attr, uattr, size);
9657 if (attr->__reserved_1)
9660 if (attr->sample_type & ~(PERF_SAMPLE_MAX-1))
9663 if (attr->read_format & ~(PERF_FORMAT_MAX-1))
9666 if (attr->sample_type & PERF_SAMPLE_BRANCH_STACK) {
9667 u64 mask = attr->branch_sample_type;
9669 /* only using defined bits */
9670 if (mask & ~(PERF_SAMPLE_BRANCH_MAX-1))
9673 /* at least one branch bit must be set */
9674 if (!(mask & ~PERF_SAMPLE_BRANCH_PLM_ALL))
9677 /* propagate priv level, when not set for branch */
9678 if (!(mask & PERF_SAMPLE_BRANCH_PLM_ALL)) {
9680 /* exclude_kernel checked on syscall entry */
9681 if (!attr->exclude_kernel)
9682 mask |= PERF_SAMPLE_BRANCH_KERNEL;
9684 if (!attr->exclude_user)
9685 mask |= PERF_SAMPLE_BRANCH_USER;
9687 if (!attr->exclude_hv)
9688 mask |= PERF_SAMPLE_BRANCH_HV;
9690 * adjust user setting (for HW filter setup)
9692 attr->branch_sample_type = mask;
9694 /* privileged levels capture (kernel, hv): check permissions */
9695 if ((mask & PERF_SAMPLE_BRANCH_PERM_PLM)
9696 && perf_paranoid_kernel() && !capable(CAP_SYS_ADMIN))
9700 if (attr->sample_type & PERF_SAMPLE_REGS_USER) {
9701 ret = perf_reg_validate(attr->sample_regs_user);
9706 if (attr->sample_type & PERF_SAMPLE_STACK_USER) {
9707 if (!arch_perf_have_user_stack_dump())
9711 * We have __u32 type for the size, but so far
9712 * we can only use __u16 as maximum due to the
9713 * __u16 sample size limit.
9715 if (attr->sample_stack_user >= USHRT_MAX)
9717 else if (!IS_ALIGNED(attr->sample_stack_user, sizeof(u64)))
9721 if (attr->sample_type & PERF_SAMPLE_REGS_INTR)
9722 ret = perf_reg_validate(attr->sample_regs_intr);
9727 put_user(sizeof(*attr), &uattr->size);
9733 perf_event_set_output(struct perf_event *event, struct perf_event *output_event)
9735 struct ring_buffer *rb = NULL;
9741 /* don't allow circular references */
9742 if (event == output_event)
9746 * Don't allow cross-cpu buffers
9748 if (output_event->cpu != event->cpu)
9752 * If its not a per-cpu rb, it must be the same task.
9754 if (output_event->cpu == -1 && output_event->ctx != event->ctx)
9758 * Mixing clocks in the same buffer is trouble you don't need.
9760 if (output_event->clock != event->clock)
9764 * Either writing ring buffer from beginning or from end.
9765 * Mixing is not allowed.
9767 if (is_write_backward(output_event) != is_write_backward(event))
9771 * If both events generate aux data, they must be on the same PMU
9773 if (has_aux(event) && has_aux(output_event) &&
9774 event->pmu != output_event->pmu)
9778 mutex_lock(&event->mmap_mutex);
9779 /* Can't redirect output if we've got an active mmap() */
9780 if (atomic_read(&event->mmap_count))
9784 /* get the rb we want to redirect to */
9785 rb = ring_buffer_get(output_event);
9790 ring_buffer_attach(event, rb);
9794 mutex_unlock(&event->mmap_mutex);
9800 static void mutex_lock_double(struct mutex *a, struct mutex *b)
9806 mutex_lock_nested(b, SINGLE_DEPTH_NESTING);
9809 static int perf_event_set_clock(struct perf_event *event, clockid_t clk_id)
9811 bool nmi_safe = false;
9814 case CLOCK_MONOTONIC:
9815 event->clock = &ktime_get_mono_fast_ns;
9819 case CLOCK_MONOTONIC_RAW:
9820 event->clock = &ktime_get_raw_fast_ns;
9824 case CLOCK_REALTIME:
9825 event->clock = &ktime_get_real_ns;
9828 case CLOCK_BOOTTIME:
9829 event->clock = &ktime_get_boot_ns;
9833 event->clock = &ktime_get_tai_ns;
9840 if (!nmi_safe && !(event->pmu->capabilities & PERF_PMU_CAP_NO_NMI))
9847 * Variation on perf_event_ctx_lock_nested(), except we take two context
9850 static struct perf_event_context *
9851 __perf_event_ctx_lock_double(struct perf_event *group_leader,
9852 struct perf_event_context *ctx)
9854 struct perf_event_context *gctx;
9858 gctx = READ_ONCE(group_leader->ctx);
9859 if (!atomic_inc_not_zero(&gctx->refcount)) {
9865 mutex_lock_double(&gctx->mutex, &ctx->mutex);
9867 if (group_leader->ctx != gctx) {
9868 mutex_unlock(&ctx->mutex);
9869 mutex_unlock(&gctx->mutex);
9878 * sys_perf_event_open - open a performance event, associate it to a task/cpu
9880 * @attr_uptr: event_id type attributes for monitoring/sampling
9883 * @group_fd: group leader event fd
9885 SYSCALL_DEFINE5(perf_event_open,
9886 struct perf_event_attr __user *, attr_uptr,
9887 pid_t, pid, int, cpu, int, group_fd, unsigned long, flags)
9889 struct perf_event *group_leader = NULL, *output_event = NULL;
9890 struct perf_event *event, *sibling;
9891 struct perf_event_attr attr;
9892 struct perf_event_context *ctx, *uninitialized_var(gctx);
9893 struct file *event_file = NULL;
9894 struct fd group = {NULL, 0};
9895 struct task_struct *task = NULL;
9900 int f_flags = O_RDWR;
9903 /* for future expandability... */
9904 if (flags & ~PERF_FLAG_ALL)
9907 err = perf_copy_attr(attr_uptr, &attr);
9911 if (!attr.exclude_kernel) {
9912 if (perf_paranoid_kernel() && !capable(CAP_SYS_ADMIN))
9916 if (attr.namespaces) {
9917 if (!capable(CAP_SYS_ADMIN))
9922 if (attr.sample_freq > sysctl_perf_event_sample_rate)
9925 if (attr.sample_period & (1ULL << 63))
9929 /* Only privileged users can get physical addresses */
9930 if ((attr.sample_type & PERF_SAMPLE_PHYS_ADDR) &&
9931 perf_paranoid_kernel() && !capable(CAP_SYS_ADMIN))
9934 if (!attr.sample_max_stack)
9935 attr.sample_max_stack = sysctl_perf_event_max_stack;
9938 * In cgroup mode, the pid argument is used to pass the fd
9939 * opened to the cgroup directory in cgroupfs. The cpu argument
9940 * designates the cpu on which to monitor threads from that
9943 if ((flags & PERF_FLAG_PID_CGROUP) && (pid == -1 || cpu == -1))
9946 if (flags & PERF_FLAG_FD_CLOEXEC)
9947 f_flags |= O_CLOEXEC;
9949 event_fd = get_unused_fd_flags(f_flags);
9953 if (group_fd != -1) {
9954 err = perf_fget_light(group_fd, &group);
9957 group_leader = group.file->private_data;
9958 if (flags & PERF_FLAG_FD_OUTPUT)
9959 output_event = group_leader;
9960 if (flags & PERF_FLAG_FD_NO_GROUP)
9961 group_leader = NULL;
9964 if (pid != -1 && !(flags & PERF_FLAG_PID_CGROUP)) {
9965 task = find_lively_task_by_vpid(pid);
9967 err = PTR_ERR(task);
9972 if (task && group_leader &&
9973 group_leader->attr.inherit != attr.inherit) {
9979 err = mutex_lock_interruptible(&task->signal->cred_guard_mutex);
9984 * Reuse ptrace permission checks for now.
9986 * We must hold cred_guard_mutex across this and any potential
9987 * perf_install_in_context() call for this new event to
9988 * serialize against exec() altering our credentials (and the
9989 * perf_event_exit_task() that could imply).
9992 if (!ptrace_may_access(task, PTRACE_MODE_READ_REALCREDS))
9996 if (flags & PERF_FLAG_PID_CGROUP)
9999 event = perf_event_alloc(&attr, cpu, task, group_leader, NULL,
10000 NULL, NULL, cgroup_fd);
10001 if (IS_ERR(event)) {
10002 err = PTR_ERR(event);
10006 if (is_sampling_event(event)) {
10007 if (event->pmu->capabilities & PERF_PMU_CAP_NO_INTERRUPT) {
10014 * Special case software events and allow them to be part of
10015 * any hardware group.
10019 if (attr.use_clockid) {
10020 err = perf_event_set_clock(event, attr.clockid);
10025 if (pmu->task_ctx_nr == perf_sw_context)
10026 event->event_caps |= PERF_EV_CAP_SOFTWARE;
10028 if (group_leader &&
10029 (is_software_event(event) != is_software_event(group_leader))) {
10030 if (is_software_event(event)) {
10032 * If event and group_leader are not both a software
10033 * event, and event is, then group leader is not.
10035 * Allow the addition of software events to !software
10036 * groups, this is safe because software events never
10037 * fail to schedule.
10039 pmu = group_leader->pmu;
10040 } else if (is_software_event(group_leader) &&
10041 (group_leader->group_caps & PERF_EV_CAP_SOFTWARE)) {
10043 * In case the group is a pure software group, and we
10044 * try to add a hardware event, move the whole group to
10045 * the hardware context.
10052 * Get the target context (task or percpu):
10054 ctx = find_get_context(pmu, task, event);
10056 err = PTR_ERR(ctx);
10060 if ((pmu->capabilities & PERF_PMU_CAP_EXCLUSIVE) && group_leader) {
10066 * Look up the group leader (we will attach this event to it):
10068 if (group_leader) {
10072 * Do not allow a recursive hierarchy (this new sibling
10073 * becoming part of another group-sibling):
10075 if (group_leader->group_leader != group_leader)
10078 /* All events in a group should have the same clock */
10079 if (group_leader->clock != event->clock)
10083 * Make sure we're both events for the same CPU;
10084 * grouping events for different CPUs is broken; since
10085 * you can never concurrently schedule them anyhow.
10087 if (group_leader->cpu != event->cpu)
10091 * Make sure we're both on the same task, or both
10094 if (group_leader->ctx->task != ctx->task)
10098 * Do not allow to attach to a group in a different task
10099 * or CPU context. If we're moving SW events, we'll fix
10100 * this up later, so allow that.
10102 if (!move_group && group_leader->ctx != ctx)
10106 * Only a group leader can be exclusive or pinned
10108 if (attr.exclusive || attr.pinned)
10112 if (output_event) {
10113 err = perf_event_set_output(event, output_event);
10118 event_file = anon_inode_getfile("[perf_event]", &perf_fops, event,
10120 if (IS_ERR(event_file)) {
10121 err = PTR_ERR(event_file);
10127 gctx = __perf_event_ctx_lock_double(group_leader, ctx);
10129 if (gctx->task == TASK_TOMBSTONE) {
10135 * Check if we raced against another sys_perf_event_open() call
10136 * moving the software group underneath us.
10138 if (!(group_leader->group_caps & PERF_EV_CAP_SOFTWARE)) {
10140 * If someone moved the group out from under us, check
10141 * if this new event wound up on the same ctx, if so
10142 * its the regular !move_group case, otherwise fail.
10148 perf_event_ctx_unlock(group_leader, gctx);
10153 mutex_lock(&ctx->mutex);
10156 if (ctx->task == TASK_TOMBSTONE) {
10161 if (!perf_event_validate_size(event)) {
10168 * Check if the @cpu we're creating an event for is online.
10170 * We use the perf_cpu_context::ctx::mutex to serialize against
10171 * the hotplug notifiers. See perf_event_{init,exit}_cpu().
10173 struct perf_cpu_context *cpuctx =
10174 container_of(ctx, struct perf_cpu_context, ctx);
10176 if (!cpuctx->online) {
10184 * Must be under the same ctx::mutex as perf_install_in_context(),
10185 * because we need to serialize with concurrent event creation.
10187 if (!exclusive_event_installable(event, ctx)) {
10188 /* exclusive and group stuff are assumed mutually exclusive */
10189 WARN_ON_ONCE(move_group);
10195 WARN_ON_ONCE(ctx->parent_ctx);
10198 * This is the point on no return; we cannot fail hereafter. This is
10199 * where we start modifying current state.
10204 * See perf_event_ctx_lock() for comments on the details
10205 * of swizzling perf_event::ctx.
10207 perf_remove_from_context(group_leader, 0);
10210 list_for_each_entry(sibling, &group_leader->sibling_list,
10212 perf_remove_from_context(sibling, 0);
10217 * Wait for everybody to stop referencing the events through
10218 * the old lists, before installing it on new lists.
10223 * Install the group siblings before the group leader.
10225 * Because a group leader will try and install the entire group
10226 * (through the sibling list, which is still in-tact), we can
10227 * end up with siblings installed in the wrong context.
10229 * By installing siblings first we NO-OP because they're not
10230 * reachable through the group lists.
10232 list_for_each_entry(sibling, &group_leader->sibling_list,
10234 perf_event__state_init(sibling);
10235 perf_install_in_context(ctx, sibling, sibling->cpu);
10240 * Removing from the context ends up with disabled
10241 * event. What we want here is event in the initial
10242 * startup state, ready to be add into new context.
10244 perf_event__state_init(group_leader);
10245 perf_install_in_context(ctx, group_leader, group_leader->cpu);
10250 * Precalculate sample_data sizes; do while holding ctx::mutex such
10251 * that we're serialized against further additions and before
10252 * perf_install_in_context() which is the point the event is active and
10253 * can use these values.
10255 perf_event__header_size(event);
10256 perf_event__id_header_size(event);
10258 event->owner = current;
10260 perf_install_in_context(ctx, event, event->cpu);
10261 perf_unpin_context(ctx);
10264 perf_event_ctx_unlock(group_leader, gctx);
10265 mutex_unlock(&ctx->mutex);
10268 mutex_unlock(&task->signal->cred_guard_mutex);
10269 put_task_struct(task);
10272 mutex_lock(¤t->perf_event_mutex);
10273 list_add_tail(&event->owner_entry, ¤t->perf_event_list);
10274 mutex_unlock(¤t->perf_event_mutex);
10277 * Drop the reference on the group_event after placing the
10278 * new event on the sibling_list. This ensures destruction
10279 * of the group leader will find the pointer to itself in
10280 * perf_group_detach().
10283 fd_install(event_fd, event_file);
10288 perf_event_ctx_unlock(group_leader, gctx);
10289 mutex_unlock(&ctx->mutex);
10293 perf_unpin_context(ctx);
10297 * If event_file is set, the fput() above will have called ->release()
10298 * and that will take care of freeing the event.
10304 mutex_unlock(&task->signal->cred_guard_mutex);
10307 put_task_struct(task);
10311 put_unused_fd(event_fd);
10316 * perf_event_create_kernel_counter
10318 * @attr: attributes of the counter to create
10319 * @cpu: cpu in which the counter is bound
10320 * @task: task to profile (NULL for percpu)
10322 struct perf_event *
10323 perf_event_create_kernel_counter(struct perf_event_attr *attr, int cpu,
10324 struct task_struct *task,
10325 perf_overflow_handler_t overflow_handler,
10328 struct perf_event_context *ctx;
10329 struct perf_event *event;
10333 * Get the target context (task or percpu):
10336 event = perf_event_alloc(attr, cpu, task, NULL, NULL,
10337 overflow_handler, context, -1);
10338 if (IS_ERR(event)) {
10339 err = PTR_ERR(event);
10343 /* Mark owner so we could distinguish it from user events. */
10344 event->owner = TASK_TOMBSTONE;
10346 ctx = find_get_context(event->pmu, task, event);
10348 err = PTR_ERR(ctx);
10352 WARN_ON_ONCE(ctx->parent_ctx);
10353 mutex_lock(&ctx->mutex);
10354 if (ctx->task == TASK_TOMBSTONE) {
10361 * Check if the @cpu we're creating an event for is online.
10363 * We use the perf_cpu_context::ctx::mutex to serialize against
10364 * the hotplug notifiers. See perf_event_{init,exit}_cpu().
10366 struct perf_cpu_context *cpuctx =
10367 container_of(ctx, struct perf_cpu_context, ctx);
10368 if (!cpuctx->online) {
10374 if (!exclusive_event_installable(event, ctx)) {
10379 perf_install_in_context(ctx, event, cpu);
10380 perf_unpin_context(ctx);
10381 mutex_unlock(&ctx->mutex);
10386 mutex_unlock(&ctx->mutex);
10387 perf_unpin_context(ctx);
10392 return ERR_PTR(err);
10394 EXPORT_SYMBOL_GPL(perf_event_create_kernel_counter);
10396 void perf_pmu_migrate_context(struct pmu *pmu, int src_cpu, int dst_cpu)
10398 struct perf_event_context *src_ctx;
10399 struct perf_event_context *dst_ctx;
10400 struct perf_event *event, *tmp;
10403 src_ctx = &per_cpu_ptr(pmu->pmu_cpu_context, src_cpu)->ctx;
10404 dst_ctx = &per_cpu_ptr(pmu->pmu_cpu_context, dst_cpu)->ctx;
10407 * See perf_event_ctx_lock() for comments on the details
10408 * of swizzling perf_event::ctx.
10410 mutex_lock_double(&src_ctx->mutex, &dst_ctx->mutex);
10411 list_for_each_entry_safe(event, tmp, &src_ctx->event_list,
10413 perf_remove_from_context(event, 0);
10414 unaccount_event_cpu(event, src_cpu);
10416 list_add(&event->migrate_entry, &events);
10420 * Wait for the events to quiesce before re-instating them.
10425 * Re-instate events in 2 passes.
10427 * Skip over group leaders and only install siblings on this first
10428 * pass, siblings will not get enabled without a leader, however a
10429 * leader will enable its siblings, even if those are still on the old
10432 list_for_each_entry_safe(event, tmp, &events, migrate_entry) {
10433 if (event->group_leader == event)
10436 list_del(&event->migrate_entry);
10437 if (event->state >= PERF_EVENT_STATE_OFF)
10438 event->state = PERF_EVENT_STATE_INACTIVE;
10439 account_event_cpu(event, dst_cpu);
10440 perf_install_in_context(dst_ctx, event, dst_cpu);
10445 * Once all the siblings are setup properly, install the group leaders
10448 list_for_each_entry_safe(event, tmp, &events, migrate_entry) {
10449 list_del(&event->migrate_entry);
10450 if (event->state >= PERF_EVENT_STATE_OFF)
10451 event->state = PERF_EVENT_STATE_INACTIVE;
10452 account_event_cpu(event, dst_cpu);
10453 perf_install_in_context(dst_ctx, event, dst_cpu);
10456 mutex_unlock(&dst_ctx->mutex);
10457 mutex_unlock(&src_ctx->mutex);
10459 EXPORT_SYMBOL_GPL(perf_pmu_migrate_context);
10461 static void sync_child_event(struct perf_event *child_event,
10462 struct task_struct *child)
10464 struct perf_event *parent_event = child_event->parent;
10467 if (child_event->attr.inherit_stat)
10468 perf_event_read_event(child_event, child);
10470 child_val = perf_event_count(child_event);
10473 * Add back the child's count to the parent's count:
10475 atomic64_add(child_val, &parent_event->child_count);
10476 atomic64_add(child_event->total_time_enabled,
10477 &parent_event->child_total_time_enabled);
10478 atomic64_add(child_event->total_time_running,
10479 &parent_event->child_total_time_running);
10483 perf_event_exit_event(struct perf_event *child_event,
10484 struct perf_event_context *child_ctx,
10485 struct task_struct *child)
10487 struct perf_event *parent_event = child_event->parent;
10490 * Do not destroy the 'original' grouping; because of the context
10491 * switch optimization the original events could've ended up in a
10492 * random child task.
10494 * If we were to destroy the original group, all group related
10495 * operations would cease to function properly after this random
10498 * Do destroy all inherited groups, we don't care about those
10499 * and being thorough is better.
10501 raw_spin_lock_irq(&child_ctx->lock);
10502 WARN_ON_ONCE(child_ctx->is_active);
10505 perf_group_detach(child_event);
10506 list_del_event(child_event, child_ctx);
10507 perf_event_set_state(child_event, PERF_EVENT_STATE_EXIT); /* is_event_hup() */
10508 raw_spin_unlock_irq(&child_ctx->lock);
10511 * Parent events are governed by their filedesc, retain them.
10513 if (!parent_event) {
10514 perf_event_wakeup(child_event);
10518 * Child events can be cleaned up.
10521 sync_child_event(child_event, child);
10524 * Remove this event from the parent's list
10526 WARN_ON_ONCE(parent_event->ctx->parent_ctx);
10527 mutex_lock(&parent_event->child_mutex);
10528 list_del_init(&child_event->child_list);
10529 mutex_unlock(&parent_event->child_mutex);
10532 * Kick perf_poll() for is_event_hup().
10534 perf_event_wakeup(parent_event);
10535 free_event(child_event);
10536 put_event(parent_event);
10539 static void perf_event_exit_task_context(struct task_struct *child, int ctxn)
10541 struct perf_event_context *child_ctx, *clone_ctx = NULL;
10542 struct perf_event *child_event, *next;
10544 WARN_ON_ONCE(child != current);
10546 child_ctx = perf_pin_task_context(child, ctxn);
10551 * In order to reduce the amount of tricky in ctx tear-down, we hold
10552 * ctx::mutex over the entire thing. This serializes against almost
10553 * everything that wants to access the ctx.
10555 * The exception is sys_perf_event_open() /
10556 * perf_event_create_kernel_count() which does find_get_context()
10557 * without ctx::mutex (it cannot because of the move_group double mutex
10558 * lock thing). See the comments in perf_install_in_context().
10560 mutex_lock(&child_ctx->mutex);
10563 * In a single ctx::lock section, de-schedule the events and detach the
10564 * context from the task such that we cannot ever get it scheduled back
10567 raw_spin_lock_irq(&child_ctx->lock);
10568 task_ctx_sched_out(__get_cpu_context(child_ctx), child_ctx, EVENT_ALL);
10571 * Now that the context is inactive, destroy the task <-> ctx relation
10572 * and mark the context dead.
10574 RCU_INIT_POINTER(child->perf_event_ctxp[ctxn], NULL);
10575 put_ctx(child_ctx); /* cannot be last */
10576 WRITE_ONCE(child_ctx->task, TASK_TOMBSTONE);
10577 put_task_struct(current); /* cannot be last */
10579 clone_ctx = unclone_ctx(child_ctx);
10580 raw_spin_unlock_irq(&child_ctx->lock);
10583 put_ctx(clone_ctx);
10586 * Report the task dead after unscheduling the events so that we
10587 * won't get any samples after PERF_RECORD_EXIT. We can however still
10588 * get a few PERF_RECORD_READ events.
10590 perf_event_task(child, child_ctx, 0);
10592 list_for_each_entry_safe(child_event, next, &child_ctx->event_list, event_entry)
10593 perf_event_exit_event(child_event, child_ctx, child);
10595 mutex_unlock(&child_ctx->mutex);
10597 put_ctx(child_ctx);
10601 * When a child task exits, feed back event values to parent events.
10603 * Can be called with cred_guard_mutex held when called from
10604 * install_exec_creds().
10606 void perf_event_exit_task(struct task_struct *child)
10608 struct perf_event *event, *tmp;
10611 mutex_lock(&child->perf_event_mutex);
10612 list_for_each_entry_safe(event, tmp, &child->perf_event_list,
10614 list_del_init(&event->owner_entry);
10617 * Ensure the list deletion is visible before we clear
10618 * the owner, closes a race against perf_release() where
10619 * we need to serialize on the owner->perf_event_mutex.
10621 smp_store_release(&event->owner, NULL);
10623 mutex_unlock(&child->perf_event_mutex);
10625 for_each_task_context_nr(ctxn)
10626 perf_event_exit_task_context(child, ctxn);
10629 * The perf_event_exit_task_context calls perf_event_task
10630 * with child's task_ctx, which generates EXIT events for
10631 * child contexts and sets child->perf_event_ctxp[] to NULL.
10632 * At this point we need to send EXIT events to cpu contexts.
10634 perf_event_task(child, NULL, 0);
10637 static void perf_free_event(struct perf_event *event,
10638 struct perf_event_context *ctx)
10640 struct perf_event *parent = event->parent;
10642 if (WARN_ON_ONCE(!parent))
10645 mutex_lock(&parent->child_mutex);
10646 list_del_init(&event->child_list);
10647 mutex_unlock(&parent->child_mutex);
10651 raw_spin_lock_irq(&ctx->lock);
10652 perf_group_detach(event);
10653 list_del_event(event, ctx);
10654 raw_spin_unlock_irq(&ctx->lock);
10659 * Free an unexposed, unused context as created by inheritance by
10660 * perf_event_init_task below, used by fork() in case of fail.
10662 * Not all locks are strictly required, but take them anyway to be nice and
10663 * help out with the lockdep assertions.
10665 void perf_event_free_task(struct task_struct *task)
10667 struct perf_event_context *ctx;
10668 struct perf_event *event, *tmp;
10671 for_each_task_context_nr(ctxn) {
10672 ctx = task->perf_event_ctxp[ctxn];
10676 mutex_lock(&ctx->mutex);
10677 raw_spin_lock_irq(&ctx->lock);
10679 * Destroy the task <-> ctx relation and mark the context dead.
10681 * This is important because even though the task hasn't been
10682 * exposed yet the context has been (through child_list).
10684 RCU_INIT_POINTER(task->perf_event_ctxp[ctxn], NULL);
10685 WRITE_ONCE(ctx->task, TASK_TOMBSTONE);
10686 put_task_struct(task); /* cannot be last */
10687 raw_spin_unlock_irq(&ctx->lock);
10689 list_for_each_entry_safe(event, tmp, &ctx->event_list, event_entry)
10690 perf_free_event(event, ctx);
10692 mutex_unlock(&ctx->mutex);
10697 void perf_event_delayed_put(struct task_struct *task)
10701 for_each_task_context_nr(ctxn)
10702 WARN_ON_ONCE(task->perf_event_ctxp[ctxn]);
10705 struct file *perf_event_get(unsigned int fd)
10709 file = fget_raw(fd);
10711 return ERR_PTR(-EBADF);
10713 if (file->f_op != &perf_fops) {
10715 return ERR_PTR(-EBADF);
10721 const struct perf_event_attr *perf_event_attrs(struct perf_event *event)
10724 return ERR_PTR(-EINVAL);
10726 return &event->attr;
10730 * Inherit a event from parent task to child task.
10733 * - valid pointer on success
10734 * - NULL for orphaned events
10735 * - IS_ERR() on error
10737 static struct perf_event *
10738 inherit_event(struct perf_event *parent_event,
10739 struct task_struct *parent,
10740 struct perf_event_context *parent_ctx,
10741 struct task_struct *child,
10742 struct perf_event *group_leader,
10743 struct perf_event_context *child_ctx)
10745 enum perf_event_state parent_state = parent_event->state;
10746 struct perf_event *child_event;
10747 unsigned long flags;
10750 * Instead of creating recursive hierarchies of events,
10751 * we link inherited events back to the original parent,
10752 * which has a filp for sure, which we use as the reference
10755 if (parent_event->parent)
10756 parent_event = parent_event->parent;
10758 child_event = perf_event_alloc(&parent_event->attr,
10761 group_leader, parent_event,
10763 if (IS_ERR(child_event))
10764 return child_event;
10767 if ((child_event->attach_state & PERF_ATTACH_TASK_DATA) &&
10768 !child_ctx->task_ctx_data) {
10769 struct pmu *pmu = child_event->pmu;
10771 child_ctx->task_ctx_data = kzalloc(pmu->task_ctx_size,
10773 if (!child_ctx->task_ctx_data) {
10774 free_event(child_event);
10780 * is_orphaned_event() and list_add_tail(&parent_event->child_list)
10781 * must be under the same lock in order to serialize against
10782 * perf_event_release_kernel(), such that either we must observe
10783 * is_orphaned_event() or they will observe us on the child_list.
10785 mutex_lock(&parent_event->child_mutex);
10786 if (is_orphaned_event(parent_event) ||
10787 !atomic_long_inc_not_zero(&parent_event->refcount)) {
10788 mutex_unlock(&parent_event->child_mutex);
10789 /* task_ctx_data is freed with child_ctx */
10790 free_event(child_event);
10794 get_ctx(child_ctx);
10797 * Make the child state follow the state of the parent event,
10798 * not its attr.disabled bit. We hold the parent's mutex,
10799 * so we won't race with perf_event_{en, dis}able_family.
10801 if (parent_state >= PERF_EVENT_STATE_INACTIVE)
10802 child_event->state = PERF_EVENT_STATE_INACTIVE;
10804 child_event->state = PERF_EVENT_STATE_OFF;
10806 if (parent_event->attr.freq) {
10807 u64 sample_period = parent_event->hw.sample_period;
10808 struct hw_perf_event *hwc = &child_event->hw;
10810 hwc->sample_period = sample_period;
10811 hwc->last_period = sample_period;
10813 local64_set(&hwc->period_left, sample_period);
10816 child_event->ctx = child_ctx;
10817 child_event->overflow_handler = parent_event->overflow_handler;
10818 child_event->overflow_handler_context
10819 = parent_event->overflow_handler_context;
10822 * Precalculate sample_data sizes
10824 perf_event__header_size(child_event);
10825 perf_event__id_header_size(child_event);
10828 * Link it up in the child's context:
10830 raw_spin_lock_irqsave(&child_ctx->lock, flags);
10831 add_event_to_ctx(child_event, child_ctx);
10832 raw_spin_unlock_irqrestore(&child_ctx->lock, flags);
10835 * Link this into the parent event's child list
10837 list_add_tail(&child_event->child_list, &parent_event->child_list);
10838 mutex_unlock(&parent_event->child_mutex);
10840 return child_event;
10844 * Inherits an event group.
10846 * This will quietly suppress orphaned events; !inherit_event() is not an error.
10847 * This matches with perf_event_release_kernel() removing all child events.
10853 static int inherit_group(struct perf_event *parent_event,
10854 struct task_struct *parent,
10855 struct perf_event_context *parent_ctx,
10856 struct task_struct *child,
10857 struct perf_event_context *child_ctx)
10859 struct perf_event *leader;
10860 struct perf_event *sub;
10861 struct perf_event *child_ctr;
10863 leader = inherit_event(parent_event, parent, parent_ctx,
10864 child, NULL, child_ctx);
10865 if (IS_ERR(leader))
10866 return PTR_ERR(leader);
10868 * @leader can be NULL here because of is_orphaned_event(). In this
10869 * case inherit_event() will create individual events, similar to what
10870 * perf_group_detach() would do anyway.
10872 list_for_each_entry(sub, &parent_event->sibling_list, group_entry) {
10873 child_ctr = inherit_event(sub, parent, parent_ctx,
10874 child, leader, child_ctx);
10875 if (IS_ERR(child_ctr))
10876 return PTR_ERR(child_ctr);
10882 * Creates the child task context and tries to inherit the event-group.
10884 * Clears @inherited_all on !attr.inherited or error. Note that we'll leave
10885 * inherited_all set when we 'fail' to inherit an orphaned event; this is
10886 * consistent with perf_event_release_kernel() removing all child events.
10893 inherit_task_group(struct perf_event *event, struct task_struct *parent,
10894 struct perf_event_context *parent_ctx,
10895 struct task_struct *child, int ctxn,
10896 int *inherited_all)
10899 struct perf_event_context *child_ctx;
10901 if (!event->attr.inherit) {
10902 *inherited_all = 0;
10906 child_ctx = child->perf_event_ctxp[ctxn];
10909 * This is executed from the parent task context, so
10910 * inherit events that have been marked for cloning.
10911 * First allocate and initialize a context for the
10914 child_ctx = alloc_perf_context(parent_ctx->pmu, child);
10918 child->perf_event_ctxp[ctxn] = child_ctx;
10921 ret = inherit_group(event, parent, parent_ctx,
10925 *inherited_all = 0;
10931 * Initialize the perf_event context in task_struct
10933 static int perf_event_init_context(struct task_struct *child, int ctxn)
10935 struct perf_event_context *child_ctx, *parent_ctx;
10936 struct perf_event_context *cloned_ctx;
10937 struct perf_event *event;
10938 struct task_struct *parent = current;
10939 int inherited_all = 1;
10940 unsigned long flags;
10943 if (likely(!parent->perf_event_ctxp[ctxn]))
10947 * If the parent's context is a clone, pin it so it won't get
10948 * swapped under us.
10950 parent_ctx = perf_pin_task_context(parent, ctxn);
10955 * No need to check if parent_ctx != NULL here; since we saw
10956 * it non-NULL earlier, the only reason for it to become NULL
10957 * is if we exit, and since we're currently in the middle of
10958 * a fork we can't be exiting at the same time.
10962 * Lock the parent list. No need to lock the child - not PID
10963 * hashed yet and not running, so nobody can access it.
10965 mutex_lock(&parent_ctx->mutex);
10968 * We dont have to disable NMIs - we are only looking at
10969 * the list, not manipulating it:
10971 list_for_each_entry(event, &parent_ctx->pinned_groups, group_entry) {
10972 ret = inherit_task_group(event, parent, parent_ctx,
10973 child, ctxn, &inherited_all);
10979 * We can't hold ctx->lock when iterating the ->flexible_group list due
10980 * to allocations, but we need to prevent rotation because
10981 * rotate_ctx() will change the list from interrupt context.
10983 raw_spin_lock_irqsave(&parent_ctx->lock, flags);
10984 parent_ctx->rotate_disable = 1;
10985 raw_spin_unlock_irqrestore(&parent_ctx->lock, flags);
10987 list_for_each_entry(event, &parent_ctx->flexible_groups, group_entry) {
10988 ret = inherit_task_group(event, parent, parent_ctx,
10989 child, ctxn, &inherited_all);
10994 raw_spin_lock_irqsave(&parent_ctx->lock, flags);
10995 parent_ctx->rotate_disable = 0;
10997 child_ctx = child->perf_event_ctxp[ctxn];
10999 if (child_ctx && inherited_all) {
11001 * Mark the child context as a clone of the parent
11002 * context, or of whatever the parent is a clone of.
11004 * Note that if the parent is a clone, the holding of
11005 * parent_ctx->lock avoids it from being uncloned.
11007 cloned_ctx = parent_ctx->parent_ctx;
11009 child_ctx->parent_ctx = cloned_ctx;
11010 child_ctx->parent_gen = parent_ctx->parent_gen;
11012 child_ctx->parent_ctx = parent_ctx;
11013 child_ctx->parent_gen = parent_ctx->generation;
11015 get_ctx(child_ctx->parent_ctx);
11018 raw_spin_unlock_irqrestore(&parent_ctx->lock, flags);
11020 mutex_unlock(&parent_ctx->mutex);
11022 perf_unpin_context(parent_ctx);
11023 put_ctx(parent_ctx);
11029 * Initialize the perf_event context in task_struct
11031 int perf_event_init_task(struct task_struct *child)
11035 memset(child->perf_event_ctxp, 0, sizeof(child->perf_event_ctxp));
11036 mutex_init(&child->perf_event_mutex);
11037 INIT_LIST_HEAD(&child->perf_event_list);
11039 for_each_task_context_nr(ctxn) {
11040 ret = perf_event_init_context(child, ctxn);
11042 perf_event_free_task(child);
11050 static void __init perf_event_init_all_cpus(void)
11052 struct swevent_htable *swhash;
11055 zalloc_cpumask_var(&perf_online_mask, GFP_KERNEL);
11057 for_each_possible_cpu(cpu) {
11058 swhash = &per_cpu(swevent_htable, cpu);
11059 mutex_init(&swhash->hlist_mutex);
11060 INIT_LIST_HEAD(&per_cpu(active_ctx_list, cpu));
11062 INIT_LIST_HEAD(&per_cpu(pmu_sb_events.list, cpu));
11063 raw_spin_lock_init(&per_cpu(pmu_sb_events.lock, cpu));
11065 #ifdef CONFIG_CGROUP_PERF
11066 INIT_LIST_HEAD(&per_cpu(cgrp_cpuctx_list, cpu));
11068 INIT_LIST_HEAD(&per_cpu(sched_cb_list, cpu));
11072 void perf_swevent_init_cpu(unsigned int cpu)
11074 struct swevent_htable *swhash = &per_cpu(swevent_htable, cpu);
11076 mutex_lock(&swhash->hlist_mutex);
11077 if (swhash->hlist_refcount > 0 && !swevent_hlist_deref(swhash)) {
11078 struct swevent_hlist *hlist;
11080 hlist = kzalloc_node(sizeof(*hlist), GFP_KERNEL, cpu_to_node(cpu));
11082 rcu_assign_pointer(swhash->swevent_hlist, hlist);
11084 mutex_unlock(&swhash->hlist_mutex);
11087 #if defined CONFIG_HOTPLUG_CPU || defined CONFIG_KEXEC_CORE
11088 static void __perf_event_exit_context(void *__info)
11090 struct perf_event_context *ctx = __info;
11091 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
11092 struct perf_event *event;
11094 raw_spin_lock(&ctx->lock);
11095 ctx_sched_out(ctx, cpuctx, EVENT_TIME);
11096 list_for_each_entry(event, &ctx->event_list, event_entry)
11097 __perf_remove_from_context(event, cpuctx, ctx, (void *)DETACH_GROUP);
11098 raw_spin_unlock(&ctx->lock);
11101 static void perf_event_exit_cpu_context(int cpu)
11103 struct perf_cpu_context *cpuctx;
11104 struct perf_event_context *ctx;
11107 mutex_lock(&pmus_lock);
11108 list_for_each_entry(pmu, &pmus, entry) {
11109 cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
11110 ctx = &cpuctx->ctx;
11112 mutex_lock(&ctx->mutex);
11113 smp_call_function_single(cpu, __perf_event_exit_context, ctx, 1);
11114 cpuctx->online = 0;
11115 mutex_unlock(&ctx->mutex);
11117 cpumask_clear_cpu(cpu, perf_online_mask);
11118 mutex_unlock(&pmus_lock);
11122 static void perf_event_exit_cpu_context(int cpu) { }
11126 int perf_event_init_cpu(unsigned int cpu)
11128 struct perf_cpu_context *cpuctx;
11129 struct perf_event_context *ctx;
11132 perf_swevent_init_cpu(cpu);
11134 mutex_lock(&pmus_lock);
11135 cpumask_set_cpu(cpu, perf_online_mask);
11136 list_for_each_entry(pmu, &pmus, entry) {
11137 cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
11138 ctx = &cpuctx->ctx;
11140 mutex_lock(&ctx->mutex);
11141 cpuctx->online = 1;
11142 mutex_unlock(&ctx->mutex);
11144 mutex_unlock(&pmus_lock);
11149 int perf_event_exit_cpu(unsigned int cpu)
11151 perf_event_exit_cpu_context(cpu);
11156 perf_reboot(struct notifier_block *notifier, unsigned long val, void *v)
11160 for_each_online_cpu(cpu)
11161 perf_event_exit_cpu(cpu);
11167 * Run the perf reboot notifier at the very last possible moment so that
11168 * the generic watchdog code runs as long as possible.
11170 static struct notifier_block perf_reboot_notifier = {
11171 .notifier_call = perf_reboot,
11172 .priority = INT_MIN,
11175 void __init perf_event_init(void)
11179 idr_init(&pmu_idr);
11181 perf_event_init_all_cpus();
11182 init_srcu_struct(&pmus_srcu);
11183 perf_pmu_register(&perf_swevent, "software", PERF_TYPE_SOFTWARE);
11184 perf_pmu_register(&perf_cpu_clock, NULL, -1);
11185 perf_pmu_register(&perf_task_clock, NULL, -1);
11186 perf_tp_register();
11187 perf_event_init_cpu(smp_processor_id());
11188 register_reboot_notifier(&perf_reboot_notifier);
11190 ret = init_hw_breakpoint();
11191 WARN(ret, "hw_breakpoint initialization failed with: %d", ret);
11194 * Build time assertion that we keep the data_head at the intended
11195 * location. IOW, validation we got the __reserved[] size right.
11197 BUILD_BUG_ON((offsetof(struct perf_event_mmap_page, data_head))
11201 ssize_t perf_event_sysfs_show(struct device *dev, struct device_attribute *attr,
11204 struct perf_pmu_events_attr *pmu_attr =
11205 container_of(attr, struct perf_pmu_events_attr, attr);
11207 if (pmu_attr->event_str)
11208 return sprintf(page, "%s\n", pmu_attr->event_str);
11212 EXPORT_SYMBOL_GPL(perf_event_sysfs_show);
11214 static int __init perf_event_sysfs_init(void)
11219 mutex_lock(&pmus_lock);
11221 ret = bus_register(&pmu_bus);
11225 list_for_each_entry(pmu, &pmus, entry) {
11226 if (!pmu->name || pmu->type < 0)
11229 ret = pmu_dev_alloc(pmu);
11230 WARN(ret, "Failed to register pmu: %s, reason %d\n", pmu->name, ret);
11232 pmu_bus_running = 1;
11236 mutex_unlock(&pmus_lock);
11240 device_initcall(perf_event_sysfs_init);
11242 #ifdef CONFIG_CGROUP_PERF
11243 static struct cgroup_subsys_state *
11244 perf_cgroup_css_alloc(struct cgroup_subsys_state *parent_css)
11246 struct perf_cgroup *jc;
11248 jc = kzalloc(sizeof(*jc), GFP_KERNEL);
11250 return ERR_PTR(-ENOMEM);
11252 jc->info = alloc_percpu(struct perf_cgroup_info);
11255 return ERR_PTR(-ENOMEM);
11261 static void perf_cgroup_css_free(struct cgroup_subsys_state *css)
11263 struct perf_cgroup *jc = container_of(css, struct perf_cgroup, css);
11265 free_percpu(jc->info);
11269 static int __perf_cgroup_move(void *info)
11271 struct task_struct *task = info;
11273 perf_cgroup_switch(task, PERF_CGROUP_SWOUT | PERF_CGROUP_SWIN);
11278 static void perf_cgroup_attach(struct cgroup_taskset *tset)
11280 struct task_struct *task;
11281 struct cgroup_subsys_state *css;
11283 cgroup_taskset_for_each(task, css, tset)
11284 task_function_call(task, __perf_cgroup_move, task);
11287 struct cgroup_subsys perf_event_cgrp_subsys = {
11288 .css_alloc = perf_cgroup_css_alloc,
11289 .css_free = perf_cgroup_css_free,
11290 .attach = perf_cgroup_attach,
11292 * Implicitly enable on dfl hierarchy so that perf events can
11293 * always be filtered by cgroup2 path as long as perf_event
11294 * controller is not mounted on a legacy hierarchy.
11296 .implicit_on_dfl = true,
11299 #endif /* CONFIG_CGROUP_PERF */