1 // SPDX-License-Identifier: GPL-2.0
3 * Performance events core code:
5 * Copyright (C) 2008 Thomas Gleixner <tglx@linutronix.de>
6 * Copyright (C) 2008-2011 Red Hat, Inc., Ingo Molnar
7 * Copyright (C) 2008-2011 Red Hat, Inc., Peter Zijlstra
8 * Copyright © 2009 Paul Mackerras, IBM Corp. <paulus@au1.ibm.com>
13 #include <linux/cpu.h>
14 #include <linux/smp.h>
15 #include <linux/idr.h>
16 #include <linux/file.h>
17 #include <linux/poll.h>
18 #include <linux/slab.h>
19 #include <linux/hash.h>
20 #include <linux/tick.h>
21 #include <linux/sysfs.h>
22 #include <linux/dcache.h>
23 #include <linux/percpu.h>
24 #include <linux/ptrace.h>
25 #include <linux/reboot.h>
26 #include <linux/vmstat.h>
27 #include <linux/device.h>
28 #include <linux/export.h>
29 #include <linux/vmalloc.h>
30 #include <linux/hardirq.h>
31 #include <linux/rculist.h>
32 #include <linux/uaccess.h>
33 #include <linux/syscalls.h>
34 #include <linux/anon_inodes.h>
35 #include <linux/kernel_stat.h>
36 #include <linux/cgroup.h>
37 #include <linux/perf_event.h>
38 #include <linux/trace_events.h>
39 #include <linux/hw_breakpoint.h>
40 #include <linux/mm_types.h>
41 #include <linux/module.h>
42 #include <linux/mman.h>
43 #include <linux/compat.h>
44 #include <linux/bpf.h>
45 #include <linux/filter.h>
46 #include <linux/namei.h>
47 #include <linux/parser.h>
48 #include <linux/sched/clock.h>
49 #include <linux/sched/mm.h>
50 #include <linux/proc_ns.h>
51 #include <linux/mount.h>
52 #include <linux/min_heap.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;
388 static atomic_t nr_ksymbol_events __read_mostly;
389 static atomic_t nr_bpf_events __read_mostly;
391 static LIST_HEAD(pmus);
392 static DEFINE_MUTEX(pmus_lock);
393 static struct srcu_struct pmus_srcu;
394 static cpumask_var_t perf_online_mask;
397 * perf event paranoia level:
398 * -1 - not paranoid at all
399 * 0 - disallow raw tracepoint access for unpriv
400 * 1 - disallow cpu events for unpriv
401 * 2 - disallow kernel profiling for unpriv
403 int sysctl_perf_event_paranoid __read_mostly = 2;
405 /* Minimum for 512 kiB + 1 user control page */
406 int sysctl_perf_event_mlock __read_mostly = 512 + (PAGE_SIZE / 1024); /* 'free' kiB per user */
409 * max perf event sample rate
411 #define DEFAULT_MAX_SAMPLE_RATE 100000
412 #define DEFAULT_SAMPLE_PERIOD_NS (NSEC_PER_SEC / DEFAULT_MAX_SAMPLE_RATE)
413 #define DEFAULT_CPU_TIME_MAX_PERCENT 25
415 int sysctl_perf_event_sample_rate __read_mostly = DEFAULT_MAX_SAMPLE_RATE;
417 static int max_samples_per_tick __read_mostly = DIV_ROUND_UP(DEFAULT_MAX_SAMPLE_RATE, HZ);
418 static int perf_sample_period_ns __read_mostly = DEFAULT_SAMPLE_PERIOD_NS;
420 static int perf_sample_allowed_ns __read_mostly =
421 DEFAULT_SAMPLE_PERIOD_NS * DEFAULT_CPU_TIME_MAX_PERCENT / 100;
423 static void update_perf_cpu_limits(void)
425 u64 tmp = perf_sample_period_ns;
427 tmp *= sysctl_perf_cpu_time_max_percent;
428 tmp = div_u64(tmp, 100);
432 WRITE_ONCE(perf_sample_allowed_ns, tmp);
435 static bool perf_rotate_context(struct perf_cpu_context *cpuctx);
437 int perf_proc_update_handler(struct ctl_table *table, int write,
438 void __user *buffer, size_t *lenp,
442 int perf_cpu = sysctl_perf_cpu_time_max_percent;
444 * If throttling is disabled don't allow the write:
446 if (write && (perf_cpu == 100 || perf_cpu == 0))
449 ret = proc_dointvec_minmax(table, write, buffer, lenp, ppos);
453 max_samples_per_tick = DIV_ROUND_UP(sysctl_perf_event_sample_rate, HZ);
454 perf_sample_period_ns = NSEC_PER_SEC / sysctl_perf_event_sample_rate;
455 update_perf_cpu_limits();
460 int sysctl_perf_cpu_time_max_percent __read_mostly = DEFAULT_CPU_TIME_MAX_PERCENT;
462 int perf_cpu_time_max_percent_handler(struct ctl_table *table, int write,
463 void __user *buffer, size_t *lenp,
466 int ret = proc_dointvec_minmax(table, write, buffer, lenp, ppos);
471 if (sysctl_perf_cpu_time_max_percent == 100 ||
472 sysctl_perf_cpu_time_max_percent == 0) {
474 "perf: Dynamic interrupt throttling disabled, can hang your system!\n");
475 WRITE_ONCE(perf_sample_allowed_ns, 0);
477 update_perf_cpu_limits();
484 * perf samples are done in some very critical code paths (NMIs).
485 * If they take too much CPU time, the system can lock up and not
486 * get any real work done. This will drop the sample rate when
487 * we detect that events are taking too long.
489 #define NR_ACCUMULATED_SAMPLES 128
490 static DEFINE_PER_CPU(u64, running_sample_length);
492 static u64 __report_avg;
493 static u64 __report_allowed;
495 static void perf_duration_warn(struct irq_work *w)
497 printk_ratelimited(KERN_INFO
498 "perf: interrupt took too long (%lld > %lld), lowering "
499 "kernel.perf_event_max_sample_rate to %d\n",
500 __report_avg, __report_allowed,
501 sysctl_perf_event_sample_rate);
504 static DEFINE_IRQ_WORK(perf_duration_work, perf_duration_warn);
506 void perf_sample_event_took(u64 sample_len_ns)
508 u64 max_len = READ_ONCE(perf_sample_allowed_ns);
516 /* Decay the counter by 1 average sample. */
517 running_len = __this_cpu_read(running_sample_length);
518 running_len -= running_len/NR_ACCUMULATED_SAMPLES;
519 running_len += sample_len_ns;
520 __this_cpu_write(running_sample_length, running_len);
523 * Note: this will be biased artifically low until we have
524 * seen NR_ACCUMULATED_SAMPLES. Doing it this way keeps us
525 * from having to maintain a count.
527 avg_len = running_len/NR_ACCUMULATED_SAMPLES;
528 if (avg_len <= max_len)
531 __report_avg = avg_len;
532 __report_allowed = max_len;
535 * Compute a throttle threshold 25% below the current duration.
537 avg_len += avg_len / 4;
538 max = (TICK_NSEC / 100) * sysctl_perf_cpu_time_max_percent;
544 WRITE_ONCE(perf_sample_allowed_ns, avg_len);
545 WRITE_ONCE(max_samples_per_tick, max);
547 sysctl_perf_event_sample_rate = max * HZ;
548 perf_sample_period_ns = NSEC_PER_SEC / sysctl_perf_event_sample_rate;
550 if (!irq_work_queue(&perf_duration_work)) {
551 early_printk("perf: interrupt took too long (%lld > %lld), lowering "
552 "kernel.perf_event_max_sample_rate to %d\n",
553 __report_avg, __report_allowed,
554 sysctl_perf_event_sample_rate);
558 static atomic64_t perf_event_id;
560 static void cpu_ctx_sched_out(struct perf_cpu_context *cpuctx,
561 enum event_type_t event_type);
563 static void cpu_ctx_sched_in(struct perf_cpu_context *cpuctx,
564 enum event_type_t event_type,
565 struct task_struct *task);
567 static void update_context_time(struct perf_event_context *ctx);
568 static u64 perf_event_time(struct perf_event *event);
570 void __weak perf_event_print_debug(void) { }
572 extern __weak const char *perf_pmu_name(void)
577 static inline u64 perf_clock(void)
579 return local_clock();
582 static inline u64 perf_event_clock(struct perf_event *event)
584 return event->clock();
588 * State based event timekeeping...
590 * The basic idea is to use event->state to determine which (if any) time
591 * fields to increment with the current delta. This means we only need to
592 * update timestamps when we change state or when they are explicitly requested
595 * Event groups make things a little more complicated, but not terribly so. The
596 * rules for a group are that if the group leader is OFF the entire group is
597 * OFF, irrespecive of what the group member states are. This results in
598 * __perf_effective_state().
600 * A futher ramification is that when a group leader flips between OFF and
601 * !OFF, we need to update all group member times.
604 * NOTE: perf_event_time() is based on the (cgroup) context time, and thus we
605 * need to make sure the relevant context time is updated before we try and
606 * update our timestamps.
609 static __always_inline enum perf_event_state
610 __perf_effective_state(struct perf_event *event)
612 struct perf_event *leader = event->group_leader;
614 if (leader->state <= PERF_EVENT_STATE_OFF)
615 return leader->state;
620 static __always_inline void
621 __perf_update_times(struct perf_event *event, u64 now, u64 *enabled, u64 *running)
623 enum perf_event_state state = __perf_effective_state(event);
624 u64 delta = now - event->tstamp;
626 *enabled = event->total_time_enabled;
627 if (state >= PERF_EVENT_STATE_INACTIVE)
630 *running = event->total_time_running;
631 if (state >= PERF_EVENT_STATE_ACTIVE)
635 static void perf_event_update_time(struct perf_event *event)
637 u64 now = perf_event_time(event);
639 __perf_update_times(event, now, &event->total_time_enabled,
640 &event->total_time_running);
644 static void perf_event_update_sibling_time(struct perf_event *leader)
646 struct perf_event *sibling;
648 for_each_sibling_event(sibling, leader)
649 perf_event_update_time(sibling);
653 perf_event_set_state(struct perf_event *event, enum perf_event_state state)
655 if (event->state == state)
658 perf_event_update_time(event);
660 * If a group leader gets enabled/disabled all its siblings
663 if ((event->state < 0) ^ (state < 0))
664 perf_event_update_sibling_time(event);
666 WRITE_ONCE(event->state, state);
669 #ifdef CONFIG_CGROUP_PERF
672 perf_cgroup_match(struct perf_event *event)
674 struct perf_event_context *ctx = event->ctx;
675 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
677 /* @event doesn't care about cgroup */
681 /* wants specific cgroup scope but @cpuctx isn't associated with any */
686 * Cgroup scoping is recursive. An event enabled for a cgroup is
687 * also enabled for all its descendant cgroups. If @cpuctx's
688 * cgroup is a descendant of @event's (the test covers identity
689 * case), it's a match.
691 return cgroup_is_descendant(cpuctx->cgrp->css.cgroup,
692 event->cgrp->css.cgroup);
695 static inline void perf_detach_cgroup(struct perf_event *event)
697 css_put(&event->cgrp->css);
701 static inline int is_cgroup_event(struct perf_event *event)
703 return event->cgrp != NULL;
706 static inline u64 perf_cgroup_event_time(struct perf_event *event)
708 struct perf_cgroup_info *t;
710 t = per_cpu_ptr(event->cgrp->info, event->cpu);
714 static inline void __update_cgrp_time(struct perf_cgroup *cgrp)
716 struct perf_cgroup_info *info;
721 info = this_cpu_ptr(cgrp->info);
723 info->time += now - info->timestamp;
724 info->timestamp = now;
727 static inline void update_cgrp_time_from_cpuctx(struct perf_cpu_context *cpuctx)
729 struct perf_cgroup *cgrp = cpuctx->cgrp;
730 struct cgroup_subsys_state *css;
733 for (css = &cgrp->css; css; css = css->parent) {
734 cgrp = container_of(css, struct perf_cgroup, css);
735 __update_cgrp_time(cgrp);
740 static inline void update_cgrp_time_from_event(struct perf_event *event)
742 struct perf_cgroup *cgrp;
745 * ensure we access cgroup data only when needed and
746 * when we know the cgroup is pinned (css_get)
748 if (!is_cgroup_event(event))
751 cgrp = perf_cgroup_from_task(current, event->ctx);
753 * Do not update time when cgroup is not active
755 if (cgroup_is_descendant(cgrp->css.cgroup, event->cgrp->css.cgroup))
756 __update_cgrp_time(event->cgrp);
760 perf_cgroup_set_timestamp(struct task_struct *task,
761 struct perf_event_context *ctx)
763 struct perf_cgroup *cgrp;
764 struct perf_cgroup_info *info;
765 struct cgroup_subsys_state *css;
768 * ctx->lock held by caller
769 * ensure we do not access cgroup data
770 * unless we have the cgroup pinned (css_get)
772 if (!task || !ctx->nr_cgroups)
775 cgrp = perf_cgroup_from_task(task, ctx);
777 for (css = &cgrp->css; css; css = css->parent) {
778 cgrp = container_of(css, struct perf_cgroup, css);
779 info = this_cpu_ptr(cgrp->info);
780 info->timestamp = ctx->timestamp;
784 static DEFINE_PER_CPU(struct list_head, cgrp_cpuctx_list);
786 #define PERF_CGROUP_SWOUT 0x1 /* cgroup switch out every event */
787 #define PERF_CGROUP_SWIN 0x2 /* cgroup switch in events based on task */
790 * reschedule events based on the cgroup constraint of task.
792 * mode SWOUT : schedule out everything
793 * mode SWIN : schedule in based on cgroup for next
795 static void perf_cgroup_switch(struct task_struct *task, int mode)
797 struct perf_cpu_context *cpuctx;
798 struct list_head *list;
802 * Disable interrupts and preemption to avoid this CPU's
803 * cgrp_cpuctx_entry to change under us.
805 local_irq_save(flags);
807 list = this_cpu_ptr(&cgrp_cpuctx_list);
808 list_for_each_entry(cpuctx, list, cgrp_cpuctx_entry) {
809 WARN_ON_ONCE(cpuctx->ctx.nr_cgroups == 0);
811 perf_ctx_lock(cpuctx, cpuctx->task_ctx);
812 perf_pmu_disable(cpuctx->ctx.pmu);
814 if (mode & PERF_CGROUP_SWOUT) {
815 cpu_ctx_sched_out(cpuctx, EVENT_ALL);
817 * must not be done before ctxswout due
818 * to event_filter_match() in event_sched_out()
823 if (mode & PERF_CGROUP_SWIN) {
824 WARN_ON_ONCE(cpuctx->cgrp);
826 * set cgrp before ctxsw in to allow
827 * event_filter_match() to not have to pass
829 * we pass the cpuctx->ctx to perf_cgroup_from_task()
830 * because cgorup events are only per-cpu
832 cpuctx->cgrp = perf_cgroup_from_task(task,
834 cpu_ctx_sched_in(cpuctx, EVENT_ALL, task);
836 perf_pmu_enable(cpuctx->ctx.pmu);
837 perf_ctx_unlock(cpuctx, cpuctx->task_ctx);
840 local_irq_restore(flags);
843 static inline void perf_cgroup_sched_out(struct task_struct *task,
844 struct task_struct *next)
846 struct perf_cgroup *cgrp1;
847 struct perf_cgroup *cgrp2 = NULL;
851 * we come here when we know perf_cgroup_events > 0
852 * we do not need to pass the ctx here because we know
853 * we are holding the rcu lock
855 cgrp1 = perf_cgroup_from_task(task, NULL);
856 cgrp2 = perf_cgroup_from_task(next, NULL);
859 * only schedule out current cgroup events if we know
860 * that we are switching to a different cgroup. Otherwise,
861 * do no touch the cgroup events.
864 perf_cgroup_switch(task, PERF_CGROUP_SWOUT);
869 static inline void perf_cgroup_sched_in(struct task_struct *prev,
870 struct task_struct *task)
872 struct perf_cgroup *cgrp1;
873 struct perf_cgroup *cgrp2 = NULL;
877 * we come here when we know perf_cgroup_events > 0
878 * we do not need to pass the ctx here because we know
879 * we are holding the rcu lock
881 cgrp1 = perf_cgroup_from_task(task, NULL);
882 cgrp2 = perf_cgroup_from_task(prev, NULL);
885 * only need to schedule in cgroup events if we are changing
886 * cgroup during ctxsw. Cgroup events were not scheduled
887 * out of ctxsw out if that was not the case.
890 perf_cgroup_switch(task, PERF_CGROUP_SWIN);
895 static int perf_cgroup_ensure_storage(struct perf_event *event,
896 struct cgroup_subsys_state *css)
898 struct perf_cpu_context *cpuctx;
899 struct perf_event **storage;
900 int cpu, heap_size, ret = 0;
903 * Allow storage to have sufficent space for an iterator for each
904 * possibly nested cgroup plus an iterator for events with no cgroup.
906 for (heap_size = 1; css; css = css->parent)
909 for_each_possible_cpu(cpu) {
910 cpuctx = per_cpu_ptr(event->pmu->pmu_cpu_context, cpu);
911 if (heap_size <= cpuctx->heap_size)
914 storage = kmalloc_node(heap_size * sizeof(struct perf_event *),
915 GFP_KERNEL, cpu_to_node(cpu));
921 raw_spin_lock_irq(&cpuctx->ctx.lock);
922 if (cpuctx->heap_size < heap_size) {
923 swap(cpuctx->heap, storage);
924 if (storage == cpuctx->heap_default)
926 cpuctx->heap_size = heap_size;
928 raw_spin_unlock_irq(&cpuctx->ctx.lock);
936 static inline int perf_cgroup_connect(int fd, struct perf_event *event,
937 struct perf_event_attr *attr,
938 struct perf_event *group_leader)
940 struct perf_cgroup *cgrp;
941 struct cgroup_subsys_state *css;
942 struct fd f = fdget(fd);
948 css = css_tryget_online_from_dir(f.file->f_path.dentry,
949 &perf_event_cgrp_subsys);
955 ret = perf_cgroup_ensure_storage(event, css);
959 cgrp = container_of(css, struct perf_cgroup, css);
963 * all events in a group must monitor
964 * the same cgroup because a task belongs
965 * to only one perf cgroup at a time
967 if (group_leader && group_leader->cgrp != cgrp) {
968 perf_detach_cgroup(event);
977 perf_cgroup_set_shadow_time(struct perf_event *event, u64 now)
979 struct perf_cgroup_info *t;
980 t = per_cpu_ptr(event->cgrp->info, event->cpu);
981 event->shadow_ctx_time = now - t->timestamp;
985 * Update cpuctx->cgrp so that it is set when first cgroup event is added and
986 * cleared when last cgroup event is removed.
989 list_update_cgroup_event(struct perf_event *event,
990 struct perf_event_context *ctx, bool add)
992 struct perf_cpu_context *cpuctx;
993 struct list_head *cpuctx_entry;
995 if (!is_cgroup_event(event))
999 * Because cgroup events are always per-cpu events,
1000 * @ctx == &cpuctx->ctx.
1002 cpuctx = container_of(ctx, struct perf_cpu_context, ctx);
1005 * Since setting cpuctx->cgrp is conditional on the current @cgrp
1006 * matching the event's cgroup, we must do this for every new event,
1007 * because if the first would mismatch, the second would not try again
1008 * and we would leave cpuctx->cgrp unset.
1010 if (add && !cpuctx->cgrp) {
1011 struct perf_cgroup *cgrp = perf_cgroup_from_task(current, ctx);
1013 if (cgroup_is_descendant(cgrp->css.cgroup, event->cgrp->css.cgroup))
1014 cpuctx->cgrp = cgrp;
1017 if (add && ctx->nr_cgroups++)
1019 else if (!add && --ctx->nr_cgroups)
1022 /* no cgroup running */
1024 cpuctx->cgrp = NULL;
1026 cpuctx_entry = &cpuctx->cgrp_cpuctx_entry;
1028 list_add(cpuctx_entry,
1029 per_cpu_ptr(&cgrp_cpuctx_list, event->cpu));
1031 list_del(cpuctx_entry);
1034 #else /* !CONFIG_CGROUP_PERF */
1037 perf_cgroup_match(struct perf_event *event)
1042 static inline void perf_detach_cgroup(struct perf_event *event)
1045 static inline int is_cgroup_event(struct perf_event *event)
1050 static inline void update_cgrp_time_from_event(struct perf_event *event)
1054 static inline void update_cgrp_time_from_cpuctx(struct perf_cpu_context *cpuctx)
1058 static inline void perf_cgroup_sched_out(struct task_struct *task,
1059 struct task_struct *next)
1063 static inline void perf_cgroup_sched_in(struct task_struct *prev,
1064 struct task_struct *task)
1068 static inline int perf_cgroup_connect(pid_t pid, struct perf_event *event,
1069 struct perf_event_attr *attr,
1070 struct perf_event *group_leader)
1076 perf_cgroup_set_timestamp(struct task_struct *task,
1077 struct perf_event_context *ctx)
1082 perf_cgroup_switch(struct task_struct *task, struct task_struct *next)
1087 perf_cgroup_set_shadow_time(struct perf_event *event, u64 now)
1091 static inline u64 perf_cgroup_event_time(struct perf_event *event)
1097 list_update_cgroup_event(struct perf_event *event,
1098 struct perf_event_context *ctx, bool add)
1105 * set default to be dependent on timer tick just
1106 * like original code
1108 #define PERF_CPU_HRTIMER (1000 / HZ)
1110 * function must be called with interrupts disabled
1112 static enum hrtimer_restart perf_mux_hrtimer_handler(struct hrtimer *hr)
1114 struct perf_cpu_context *cpuctx;
1117 lockdep_assert_irqs_disabled();
1119 cpuctx = container_of(hr, struct perf_cpu_context, hrtimer);
1120 rotations = perf_rotate_context(cpuctx);
1122 raw_spin_lock(&cpuctx->hrtimer_lock);
1124 hrtimer_forward_now(hr, cpuctx->hrtimer_interval);
1126 cpuctx->hrtimer_active = 0;
1127 raw_spin_unlock(&cpuctx->hrtimer_lock);
1129 return rotations ? HRTIMER_RESTART : HRTIMER_NORESTART;
1132 static void __perf_mux_hrtimer_init(struct perf_cpu_context *cpuctx, int cpu)
1134 struct hrtimer *timer = &cpuctx->hrtimer;
1135 struct pmu *pmu = cpuctx->ctx.pmu;
1138 /* no multiplexing needed for SW PMU */
1139 if (pmu->task_ctx_nr == perf_sw_context)
1143 * check default is sane, if not set then force to
1144 * default interval (1/tick)
1146 interval = pmu->hrtimer_interval_ms;
1148 interval = pmu->hrtimer_interval_ms = PERF_CPU_HRTIMER;
1150 cpuctx->hrtimer_interval = ns_to_ktime(NSEC_PER_MSEC * interval);
1152 raw_spin_lock_init(&cpuctx->hrtimer_lock);
1153 hrtimer_init(timer, CLOCK_MONOTONIC, HRTIMER_MODE_ABS_PINNED_HARD);
1154 timer->function = perf_mux_hrtimer_handler;
1157 static int perf_mux_hrtimer_restart(struct perf_cpu_context *cpuctx)
1159 struct hrtimer *timer = &cpuctx->hrtimer;
1160 struct pmu *pmu = cpuctx->ctx.pmu;
1161 unsigned long flags;
1163 /* not for SW PMU */
1164 if (pmu->task_ctx_nr == perf_sw_context)
1167 raw_spin_lock_irqsave(&cpuctx->hrtimer_lock, flags);
1168 if (!cpuctx->hrtimer_active) {
1169 cpuctx->hrtimer_active = 1;
1170 hrtimer_forward_now(timer, cpuctx->hrtimer_interval);
1171 hrtimer_start_expires(timer, HRTIMER_MODE_ABS_PINNED_HARD);
1173 raw_spin_unlock_irqrestore(&cpuctx->hrtimer_lock, flags);
1178 void perf_pmu_disable(struct pmu *pmu)
1180 int *count = this_cpu_ptr(pmu->pmu_disable_count);
1182 pmu->pmu_disable(pmu);
1185 void perf_pmu_enable(struct pmu *pmu)
1187 int *count = this_cpu_ptr(pmu->pmu_disable_count);
1189 pmu->pmu_enable(pmu);
1192 static DEFINE_PER_CPU(struct list_head, active_ctx_list);
1195 * perf_event_ctx_activate(), perf_event_ctx_deactivate(), and
1196 * perf_event_task_tick() are fully serialized because they're strictly cpu
1197 * affine and perf_event_ctx{activate,deactivate} are called with IRQs
1198 * disabled, while perf_event_task_tick is called from IRQ context.
1200 static void perf_event_ctx_activate(struct perf_event_context *ctx)
1202 struct list_head *head = this_cpu_ptr(&active_ctx_list);
1204 lockdep_assert_irqs_disabled();
1206 WARN_ON(!list_empty(&ctx->active_ctx_list));
1208 list_add(&ctx->active_ctx_list, head);
1211 static void perf_event_ctx_deactivate(struct perf_event_context *ctx)
1213 lockdep_assert_irqs_disabled();
1215 WARN_ON(list_empty(&ctx->active_ctx_list));
1217 list_del_init(&ctx->active_ctx_list);
1220 static void get_ctx(struct perf_event_context *ctx)
1222 refcount_inc(&ctx->refcount);
1225 static void free_ctx(struct rcu_head *head)
1227 struct perf_event_context *ctx;
1229 ctx = container_of(head, struct perf_event_context, rcu_head);
1230 kfree(ctx->task_ctx_data);
1234 static void put_ctx(struct perf_event_context *ctx)
1236 if (refcount_dec_and_test(&ctx->refcount)) {
1237 if (ctx->parent_ctx)
1238 put_ctx(ctx->parent_ctx);
1239 if (ctx->task && ctx->task != TASK_TOMBSTONE)
1240 put_task_struct(ctx->task);
1241 call_rcu(&ctx->rcu_head, free_ctx);
1246 * Because of perf_event::ctx migration in sys_perf_event_open::move_group and
1247 * perf_pmu_migrate_context() we need some magic.
1249 * Those places that change perf_event::ctx will hold both
1250 * perf_event_ctx::mutex of the 'old' and 'new' ctx value.
1252 * Lock ordering is by mutex address. There are two other sites where
1253 * perf_event_context::mutex nests and those are:
1255 * - perf_event_exit_task_context() [ child , 0 ]
1256 * perf_event_exit_event()
1257 * put_event() [ parent, 1 ]
1259 * - perf_event_init_context() [ parent, 0 ]
1260 * inherit_task_group()
1263 * perf_event_alloc()
1265 * perf_try_init_event() [ child , 1 ]
1267 * While it appears there is an obvious deadlock here -- the parent and child
1268 * nesting levels are inverted between the two. This is in fact safe because
1269 * life-time rules separate them. That is an exiting task cannot fork, and a
1270 * spawning task cannot (yet) exit.
1272 * But remember that that these are parent<->child context relations, and
1273 * migration does not affect children, therefore these two orderings should not
1276 * The change in perf_event::ctx does not affect children (as claimed above)
1277 * because the sys_perf_event_open() case will install a new event and break
1278 * the ctx parent<->child relation, and perf_pmu_migrate_context() is only
1279 * concerned with cpuctx and that doesn't have children.
1281 * The places that change perf_event::ctx will issue:
1283 * perf_remove_from_context();
1284 * synchronize_rcu();
1285 * perf_install_in_context();
1287 * to affect the change. The remove_from_context() + synchronize_rcu() should
1288 * quiesce the event, after which we can install it in the new location. This
1289 * means that only external vectors (perf_fops, prctl) can perturb the event
1290 * while in transit. Therefore all such accessors should also acquire
1291 * perf_event_context::mutex to serialize against this.
1293 * However; because event->ctx can change while we're waiting to acquire
1294 * ctx->mutex we must be careful and use the below perf_event_ctx_lock()
1299 * task_struct::perf_event_mutex
1300 * perf_event_context::mutex
1301 * perf_event::child_mutex;
1302 * perf_event_context::lock
1303 * perf_event::mmap_mutex
1305 * perf_addr_filters_head::lock
1309 * cpuctx->mutex / perf_event_context::mutex
1311 static struct perf_event_context *
1312 perf_event_ctx_lock_nested(struct perf_event *event, int nesting)
1314 struct perf_event_context *ctx;
1318 ctx = READ_ONCE(event->ctx);
1319 if (!refcount_inc_not_zero(&ctx->refcount)) {
1325 mutex_lock_nested(&ctx->mutex, nesting);
1326 if (event->ctx != ctx) {
1327 mutex_unlock(&ctx->mutex);
1335 static inline struct perf_event_context *
1336 perf_event_ctx_lock(struct perf_event *event)
1338 return perf_event_ctx_lock_nested(event, 0);
1341 static void perf_event_ctx_unlock(struct perf_event *event,
1342 struct perf_event_context *ctx)
1344 mutex_unlock(&ctx->mutex);
1349 * This must be done under the ctx->lock, such as to serialize against
1350 * context_equiv(), therefore we cannot call put_ctx() since that might end up
1351 * calling scheduler related locks and ctx->lock nests inside those.
1353 static __must_check struct perf_event_context *
1354 unclone_ctx(struct perf_event_context *ctx)
1356 struct perf_event_context *parent_ctx = ctx->parent_ctx;
1358 lockdep_assert_held(&ctx->lock);
1361 ctx->parent_ctx = NULL;
1367 static u32 perf_event_pid_type(struct perf_event *event, struct task_struct *p,
1372 * only top level events have the pid namespace they were created in
1375 event = event->parent;
1377 nr = __task_pid_nr_ns(p, type, event->ns);
1378 /* avoid -1 if it is idle thread or runs in another ns */
1379 if (!nr && !pid_alive(p))
1384 static u32 perf_event_pid(struct perf_event *event, struct task_struct *p)
1386 return perf_event_pid_type(event, p, PIDTYPE_TGID);
1389 static u32 perf_event_tid(struct perf_event *event, struct task_struct *p)
1391 return perf_event_pid_type(event, p, PIDTYPE_PID);
1395 * If we inherit events we want to return the parent event id
1398 static u64 primary_event_id(struct perf_event *event)
1403 id = event->parent->id;
1409 * Get the perf_event_context for a task and lock it.
1411 * This has to cope with with the fact that until it is locked,
1412 * the context could get moved to another task.
1414 static struct perf_event_context *
1415 perf_lock_task_context(struct task_struct *task, int ctxn, unsigned long *flags)
1417 struct perf_event_context *ctx;
1421 * One of the few rules of preemptible RCU is that one cannot do
1422 * rcu_read_unlock() while holding a scheduler (or nested) lock when
1423 * part of the read side critical section was irqs-enabled -- see
1424 * rcu_read_unlock_special().
1426 * Since ctx->lock nests under rq->lock we must ensure the entire read
1427 * side critical section has interrupts disabled.
1429 local_irq_save(*flags);
1431 ctx = rcu_dereference(task->perf_event_ctxp[ctxn]);
1434 * If this context is a clone of another, it might
1435 * get swapped for another underneath us by
1436 * perf_event_task_sched_out, though the
1437 * rcu_read_lock() protects us from any context
1438 * getting freed. Lock the context and check if it
1439 * got swapped before we could get the lock, and retry
1440 * if so. If we locked the right context, then it
1441 * can't get swapped on us any more.
1443 raw_spin_lock(&ctx->lock);
1444 if (ctx != rcu_dereference(task->perf_event_ctxp[ctxn])) {
1445 raw_spin_unlock(&ctx->lock);
1447 local_irq_restore(*flags);
1451 if (ctx->task == TASK_TOMBSTONE ||
1452 !refcount_inc_not_zero(&ctx->refcount)) {
1453 raw_spin_unlock(&ctx->lock);
1456 WARN_ON_ONCE(ctx->task != task);
1461 local_irq_restore(*flags);
1466 * Get the context for a task and increment its pin_count so it
1467 * can't get swapped to another task. This also increments its
1468 * reference count so that the context can't get freed.
1470 static struct perf_event_context *
1471 perf_pin_task_context(struct task_struct *task, int ctxn)
1473 struct perf_event_context *ctx;
1474 unsigned long flags;
1476 ctx = perf_lock_task_context(task, ctxn, &flags);
1479 raw_spin_unlock_irqrestore(&ctx->lock, flags);
1484 static void perf_unpin_context(struct perf_event_context *ctx)
1486 unsigned long flags;
1488 raw_spin_lock_irqsave(&ctx->lock, flags);
1490 raw_spin_unlock_irqrestore(&ctx->lock, flags);
1494 * Update the record of the current time in a context.
1496 static void update_context_time(struct perf_event_context *ctx)
1498 u64 now = perf_clock();
1500 ctx->time += now - ctx->timestamp;
1501 ctx->timestamp = now;
1504 static u64 perf_event_time(struct perf_event *event)
1506 struct perf_event_context *ctx = event->ctx;
1508 if (is_cgroup_event(event))
1509 return perf_cgroup_event_time(event);
1511 return ctx ? ctx->time : 0;
1514 static enum event_type_t get_event_type(struct perf_event *event)
1516 struct perf_event_context *ctx = event->ctx;
1517 enum event_type_t event_type;
1519 lockdep_assert_held(&ctx->lock);
1522 * It's 'group type', really, because if our group leader is
1523 * pinned, so are we.
1525 if (event->group_leader != event)
1526 event = event->group_leader;
1528 event_type = event->attr.pinned ? EVENT_PINNED : EVENT_FLEXIBLE;
1530 event_type |= EVENT_CPU;
1536 * Helper function to initialize event group nodes.
1538 static void init_event_group(struct perf_event *event)
1540 RB_CLEAR_NODE(&event->group_node);
1541 event->group_index = 0;
1545 * Extract pinned or flexible groups from the context
1546 * based on event attrs bits.
1548 static struct perf_event_groups *
1549 get_event_groups(struct perf_event *event, struct perf_event_context *ctx)
1551 if (event->attr.pinned)
1552 return &ctx->pinned_groups;
1554 return &ctx->flexible_groups;
1558 * Helper function to initializes perf_event_group trees.
1560 static void perf_event_groups_init(struct perf_event_groups *groups)
1562 groups->tree = RB_ROOT;
1567 * Compare function for event groups;
1569 * Implements complex key that first sorts by CPU and then by virtual index
1570 * which provides ordering when rotating groups for the same CPU.
1573 perf_event_groups_less(struct perf_event *left, struct perf_event *right)
1575 if (left->cpu < right->cpu)
1577 if (left->cpu > right->cpu)
1580 #ifdef CONFIG_CGROUP_PERF
1581 if (left->cgrp != right->cgrp) {
1582 if (!left->cgrp || !left->cgrp->css.cgroup) {
1584 * Left has no cgroup but right does, no cgroups come
1589 if (!right->cgrp || !right->cgrp->css.cgroup) {
1591 * Right has no cgroup but left does, no cgroups come
1596 /* Two dissimilar cgroups, order by id. */
1597 if (left->cgrp->css.cgroup->kn->id < right->cgrp->css.cgroup->kn->id)
1604 if (left->group_index < right->group_index)
1606 if (left->group_index > right->group_index)
1613 * Insert @event into @groups' tree; using {@event->cpu, ++@groups->index} for
1614 * key (see perf_event_groups_less). This places it last inside the CPU
1618 perf_event_groups_insert(struct perf_event_groups *groups,
1619 struct perf_event *event)
1621 struct perf_event *node_event;
1622 struct rb_node *parent;
1623 struct rb_node **node;
1625 event->group_index = ++groups->index;
1627 node = &groups->tree.rb_node;
1632 node_event = container_of(*node, struct perf_event, group_node);
1634 if (perf_event_groups_less(event, node_event))
1635 node = &parent->rb_left;
1637 node = &parent->rb_right;
1640 rb_link_node(&event->group_node, parent, node);
1641 rb_insert_color(&event->group_node, &groups->tree);
1645 * Helper function to insert event into the pinned or flexible groups.
1648 add_event_to_groups(struct perf_event *event, struct perf_event_context *ctx)
1650 struct perf_event_groups *groups;
1652 groups = get_event_groups(event, ctx);
1653 perf_event_groups_insert(groups, event);
1657 * Delete a group from a tree.
1660 perf_event_groups_delete(struct perf_event_groups *groups,
1661 struct perf_event *event)
1663 WARN_ON_ONCE(RB_EMPTY_NODE(&event->group_node) ||
1664 RB_EMPTY_ROOT(&groups->tree));
1666 rb_erase(&event->group_node, &groups->tree);
1667 init_event_group(event);
1671 * Helper function to delete event from its groups.
1674 del_event_from_groups(struct perf_event *event, struct perf_event_context *ctx)
1676 struct perf_event_groups *groups;
1678 groups = get_event_groups(event, ctx);
1679 perf_event_groups_delete(groups, event);
1683 * Get the leftmost event in the cpu/cgroup subtree.
1685 static struct perf_event *
1686 perf_event_groups_first(struct perf_event_groups *groups, int cpu,
1687 struct cgroup *cgrp)
1689 struct perf_event *node_event = NULL, *match = NULL;
1690 struct rb_node *node = groups->tree.rb_node;
1691 #ifdef CONFIG_CGROUP_PERF
1692 u64 node_cgrp_id, cgrp_id = 0;
1695 cgrp_id = cgrp->kn->id;
1699 node_event = container_of(node, struct perf_event, group_node);
1701 if (cpu < node_event->cpu) {
1702 node = node->rb_left;
1705 if (cpu > node_event->cpu) {
1706 node = node->rb_right;
1709 #ifdef CONFIG_CGROUP_PERF
1711 if (node_event->cgrp && node_event->cgrp->css.cgroup)
1712 node_cgrp_id = node_event->cgrp->css.cgroup->kn->id;
1714 if (cgrp_id < node_cgrp_id) {
1715 node = node->rb_left;
1718 if (cgrp_id > node_cgrp_id) {
1719 node = node->rb_right;
1724 node = node->rb_left;
1731 * Like rb_entry_next_safe() for the @cpu subtree.
1733 static struct perf_event *
1734 perf_event_groups_next(struct perf_event *event)
1736 struct perf_event *next;
1737 #ifdef CONFIG_CGROUP_PERF
1738 u64 curr_cgrp_id = 0;
1739 u64 next_cgrp_id = 0;
1742 next = rb_entry_safe(rb_next(&event->group_node), typeof(*event), group_node);
1743 if (next == NULL || next->cpu != event->cpu)
1746 #ifdef CONFIG_CGROUP_PERF
1747 if (event->cgrp && event->cgrp->css.cgroup)
1748 curr_cgrp_id = event->cgrp->css.cgroup->kn->id;
1750 if (next->cgrp && next->cgrp->css.cgroup)
1751 next_cgrp_id = next->cgrp->css.cgroup->kn->id;
1753 if (curr_cgrp_id != next_cgrp_id)
1760 * Iterate through the whole groups tree.
1762 #define perf_event_groups_for_each(event, groups) \
1763 for (event = rb_entry_safe(rb_first(&((groups)->tree)), \
1764 typeof(*event), group_node); event; \
1765 event = rb_entry_safe(rb_next(&event->group_node), \
1766 typeof(*event), group_node))
1769 * Add an event from the lists for its context.
1770 * Must be called with ctx->mutex and ctx->lock held.
1773 list_add_event(struct perf_event *event, struct perf_event_context *ctx)
1775 lockdep_assert_held(&ctx->lock);
1777 WARN_ON_ONCE(event->attach_state & PERF_ATTACH_CONTEXT);
1778 event->attach_state |= PERF_ATTACH_CONTEXT;
1780 event->tstamp = perf_event_time(event);
1783 * If we're a stand alone event or group leader, we go to the context
1784 * list, group events are kept attached to the group so that
1785 * perf_group_detach can, at all times, locate all siblings.
1787 if (event->group_leader == event) {
1788 event->group_caps = event->event_caps;
1789 add_event_to_groups(event, ctx);
1792 list_update_cgroup_event(event, ctx, true);
1794 list_add_rcu(&event->event_entry, &ctx->event_list);
1796 if (event->attr.inherit_stat)
1803 * Initialize event state based on the perf_event_attr::disabled.
1805 static inline void perf_event__state_init(struct perf_event *event)
1807 event->state = event->attr.disabled ? PERF_EVENT_STATE_OFF :
1808 PERF_EVENT_STATE_INACTIVE;
1811 static void __perf_event_read_size(struct perf_event *event, int nr_siblings)
1813 int entry = sizeof(u64); /* value */
1817 if (event->attr.read_format & PERF_FORMAT_TOTAL_TIME_ENABLED)
1818 size += sizeof(u64);
1820 if (event->attr.read_format & PERF_FORMAT_TOTAL_TIME_RUNNING)
1821 size += sizeof(u64);
1823 if (event->attr.read_format & PERF_FORMAT_ID)
1824 entry += sizeof(u64);
1826 if (event->attr.read_format & PERF_FORMAT_GROUP) {
1828 size += sizeof(u64);
1832 event->read_size = size;
1835 static void __perf_event_header_size(struct perf_event *event, u64 sample_type)
1837 struct perf_sample_data *data;
1840 if (sample_type & PERF_SAMPLE_IP)
1841 size += sizeof(data->ip);
1843 if (sample_type & PERF_SAMPLE_ADDR)
1844 size += sizeof(data->addr);
1846 if (sample_type & PERF_SAMPLE_PERIOD)
1847 size += sizeof(data->period);
1849 if (sample_type & PERF_SAMPLE_WEIGHT)
1850 size += sizeof(data->weight);
1852 if (sample_type & PERF_SAMPLE_READ)
1853 size += event->read_size;
1855 if (sample_type & PERF_SAMPLE_DATA_SRC)
1856 size += sizeof(data->data_src.val);
1858 if (sample_type & PERF_SAMPLE_TRANSACTION)
1859 size += sizeof(data->txn);
1861 if (sample_type & PERF_SAMPLE_PHYS_ADDR)
1862 size += sizeof(data->phys_addr);
1864 event->header_size = size;
1868 * Called at perf_event creation and when events are attached/detached from a
1871 static void perf_event__header_size(struct perf_event *event)
1873 __perf_event_read_size(event,
1874 event->group_leader->nr_siblings);
1875 __perf_event_header_size(event, event->attr.sample_type);
1878 static void perf_event__id_header_size(struct perf_event *event)
1880 struct perf_sample_data *data;
1881 u64 sample_type = event->attr.sample_type;
1884 if (sample_type & PERF_SAMPLE_TID)
1885 size += sizeof(data->tid_entry);
1887 if (sample_type & PERF_SAMPLE_TIME)
1888 size += sizeof(data->time);
1890 if (sample_type & PERF_SAMPLE_IDENTIFIER)
1891 size += sizeof(data->id);
1893 if (sample_type & PERF_SAMPLE_ID)
1894 size += sizeof(data->id);
1896 if (sample_type & PERF_SAMPLE_STREAM_ID)
1897 size += sizeof(data->stream_id);
1899 if (sample_type & PERF_SAMPLE_CPU)
1900 size += sizeof(data->cpu_entry);
1902 event->id_header_size = size;
1905 static bool perf_event_validate_size(struct perf_event *event)
1908 * The values computed here will be over-written when we actually
1911 __perf_event_read_size(event, event->group_leader->nr_siblings + 1);
1912 __perf_event_header_size(event, event->attr.sample_type & ~PERF_SAMPLE_READ);
1913 perf_event__id_header_size(event);
1916 * Sum the lot; should not exceed the 64k limit we have on records.
1917 * Conservative limit to allow for callchains and other variable fields.
1919 if (event->read_size + event->header_size +
1920 event->id_header_size + sizeof(struct perf_event_header) >= 16*1024)
1926 static void perf_group_attach(struct perf_event *event)
1928 struct perf_event *group_leader = event->group_leader, *pos;
1930 lockdep_assert_held(&event->ctx->lock);
1933 * We can have double attach due to group movement in perf_event_open.
1935 if (event->attach_state & PERF_ATTACH_GROUP)
1938 event->attach_state |= PERF_ATTACH_GROUP;
1940 if (group_leader == event)
1943 WARN_ON_ONCE(group_leader->ctx != event->ctx);
1945 group_leader->group_caps &= event->event_caps;
1947 list_add_tail(&event->sibling_list, &group_leader->sibling_list);
1948 group_leader->nr_siblings++;
1950 perf_event__header_size(group_leader);
1952 for_each_sibling_event(pos, group_leader)
1953 perf_event__header_size(pos);
1957 * Remove an event from the lists for its context.
1958 * Must be called with ctx->mutex and ctx->lock held.
1961 list_del_event(struct perf_event *event, struct perf_event_context *ctx)
1963 WARN_ON_ONCE(event->ctx != ctx);
1964 lockdep_assert_held(&ctx->lock);
1967 * We can have double detach due to exit/hot-unplug + close.
1969 if (!(event->attach_state & PERF_ATTACH_CONTEXT))
1972 event->attach_state &= ~PERF_ATTACH_CONTEXT;
1974 list_update_cgroup_event(event, ctx, false);
1977 if (event->attr.inherit_stat)
1980 list_del_rcu(&event->event_entry);
1982 if (event->group_leader == event)
1983 del_event_from_groups(event, ctx);
1986 * If event was in error state, then keep it
1987 * that way, otherwise bogus counts will be
1988 * returned on read(). The only way to get out
1989 * of error state is by explicit re-enabling
1992 if (event->state > PERF_EVENT_STATE_OFF)
1993 perf_event_set_state(event, PERF_EVENT_STATE_OFF);
1999 perf_aux_output_match(struct perf_event *event, struct perf_event *aux_event)
2001 if (!has_aux(aux_event))
2004 if (!event->pmu->aux_output_match)
2007 return event->pmu->aux_output_match(aux_event);
2010 static void put_event(struct perf_event *event);
2011 static void event_sched_out(struct perf_event *event,
2012 struct perf_cpu_context *cpuctx,
2013 struct perf_event_context *ctx);
2015 static void perf_put_aux_event(struct perf_event *event)
2017 struct perf_event_context *ctx = event->ctx;
2018 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
2019 struct perf_event *iter;
2022 * If event uses aux_event tear down the link
2024 if (event->aux_event) {
2025 iter = event->aux_event;
2026 event->aux_event = NULL;
2032 * If the event is an aux_event, tear down all links to
2033 * it from other events.
2035 for_each_sibling_event(iter, event->group_leader) {
2036 if (iter->aux_event != event)
2039 iter->aux_event = NULL;
2043 * If it's ACTIVE, schedule it out and put it into ERROR
2044 * state so that we don't try to schedule it again. Note
2045 * that perf_event_enable() will clear the ERROR status.
2047 event_sched_out(iter, cpuctx, ctx);
2048 perf_event_set_state(event, PERF_EVENT_STATE_ERROR);
2052 static bool perf_need_aux_event(struct perf_event *event)
2054 return !!event->attr.aux_output || !!event->attr.aux_sample_size;
2057 static int perf_get_aux_event(struct perf_event *event,
2058 struct perf_event *group_leader)
2061 * Our group leader must be an aux event if we want to be
2062 * an aux_output. This way, the aux event will precede its
2063 * aux_output events in the group, and therefore will always
2070 * aux_output and aux_sample_size are mutually exclusive.
2072 if (event->attr.aux_output && event->attr.aux_sample_size)
2075 if (event->attr.aux_output &&
2076 !perf_aux_output_match(event, group_leader))
2079 if (event->attr.aux_sample_size && !group_leader->pmu->snapshot_aux)
2082 if (!atomic_long_inc_not_zero(&group_leader->refcount))
2086 * Link aux_outputs to their aux event; this is undone in
2087 * perf_group_detach() by perf_put_aux_event(). When the
2088 * group in torn down, the aux_output events loose their
2089 * link to the aux_event and can't schedule any more.
2091 event->aux_event = group_leader;
2096 static inline struct list_head *get_event_list(struct perf_event *event)
2098 struct perf_event_context *ctx = event->ctx;
2099 return event->attr.pinned ? &ctx->pinned_active : &ctx->flexible_active;
2102 static void perf_group_detach(struct perf_event *event)
2104 struct perf_event *sibling, *tmp;
2105 struct perf_event_context *ctx = event->ctx;
2107 lockdep_assert_held(&ctx->lock);
2110 * We can have double detach due to exit/hot-unplug + close.
2112 if (!(event->attach_state & PERF_ATTACH_GROUP))
2115 event->attach_state &= ~PERF_ATTACH_GROUP;
2117 perf_put_aux_event(event);
2120 * If this is a sibling, remove it from its group.
2122 if (event->group_leader != event) {
2123 list_del_init(&event->sibling_list);
2124 event->group_leader->nr_siblings--;
2129 * If this was a group event with sibling events then
2130 * upgrade the siblings to singleton events by adding them
2131 * to whatever list we are on.
2133 list_for_each_entry_safe(sibling, tmp, &event->sibling_list, sibling_list) {
2135 sibling->group_leader = sibling;
2136 list_del_init(&sibling->sibling_list);
2138 /* Inherit group flags from the previous leader */
2139 sibling->group_caps = event->group_caps;
2141 if (!RB_EMPTY_NODE(&event->group_node)) {
2142 add_event_to_groups(sibling, event->ctx);
2144 if (sibling->state == PERF_EVENT_STATE_ACTIVE)
2145 list_add_tail(&sibling->active_list, get_event_list(sibling));
2148 WARN_ON_ONCE(sibling->ctx != event->ctx);
2152 perf_event__header_size(event->group_leader);
2154 for_each_sibling_event(tmp, event->group_leader)
2155 perf_event__header_size(tmp);
2158 static bool is_orphaned_event(struct perf_event *event)
2160 return event->state == PERF_EVENT_STATE_DEAD;
2163 static inline int __pmu_filter_match(struct perf_event *event)
2165 struct pmu *pmu = event->pmu;
2166 return pmu->filter_match ? pmu->filter_match(event) : 1;
2170 * Check whether we should attempt to schedule an event group based on
2171 * PMU-specific filtering. An event group can consist of HW and SW events,
2172 * potentially with a SW leader, so we must check all the filters, to
2173 * determine whether a group is schedulable:
2175 static inline int pmu_filter_match(struct perf_event *event)
2177 struct perf_event *sibling;
2179 if (!__pmu_filter_match(event))
2182 for_each_sibling_event(sibling, event) {
2183 if (!__pmu_filter_match(sibling))
2191 event_filter_match(struct perf_event *event)
2193 return (event->cpu == -1 || event->cpu == smp_processor_id()) &&
2194 perf_cgroup_match(event) && pmu_filter_match(event);
2198 event_sched_out(struct perf_event *event,
2199 struct perf_cpu_context *cpuctx,
2200 struct perf_event_context *ctx)
2202 enum perf_event_state state = PERF_EVENT_STATE_INACTIVE;
2204 WARN_ON_ONCE(event->ctx != ctx);
2205 lockdep_assert_held(&ctx->lock);
2207 if (event->state != PERF_EVENT_STATE_ACTIVE)
2211 * Asymmetry; we only schedule events _IN_ through ctx_sched_in(), but
2212 * we can schedule events _OUT_ individually through things like
2213 * __perf_remove_from_context().
2215 list_del_init(&event->active_list);
2217 perf_pmu_disable(event->pmu);
2219 event->pmu->del(event, 0);
2222 if (READ_ONCE(event->pending_disable) >= 0) {
2223 WRITE_ONCE(event->pending_disable, -1);
2224 state = PERF_EVENT_STATE_OFF;
2226 perf_event_set_state(event, state);
2228 if (!is_software_event(event))
2229 cpuctx->active_oncpu--;
2230 if (!--ctx->nr_active)
2231 perf_event_ctx_deactivate(ctx);
2232 if (event->attr.freq && event->attr.sample_freq)
2234 if (event->attr.exclusive || !cpuctx->active_oncpu)
2235 cpuctx->exclusive = 0;
2237 perf_pmu_enable(event->pmu);
2241 group_sched_out(struct perf_event *group_event,
2242 struct perf_cpu_context *cpuctx,
2243 struct perf_event_context *ctx)
2245 struct perf_event *event;
2247 if (group_event->state != PERF_EVENT_STATE_ACTIVE)
2250 perf_pmu_disable(ctx->pmu);
2252 event_sched_out(group_event, cpuctx, ctx);
2255 * Schedule out siblings (if any):
2257 for_each_sibling_event(event, group_event)
2258 event_sched_out(event, cpuctx, ctx);
2260 perf_pmu_enable(ctx->pmu);
2262 if (group_event->attr.exclusive)
2263 cpuctx->exclusive = 0;
2266 #define DETACH_GROUP 0x01UL
2269 * Cross CPU call to remove a performance event
2271 * We disable the event on the hardware level first. After that we
2272 * remove it from the context list.
2275 __perf_remove_from_context(struct perf_event *event,
2276 struct perf_cpu_context *cpuctx,
2277 struct perf_event_context *ctx,
2280 unsigned long flags = (unsigned long)info;
2282 if (ctx->is_active & EVENT_TIME) {
2283 update_context_time(ctx);
2284 update_cgrp_time_from_cpuctx(cpuctx);
2287 event_sched_out(event, cpuctx, ctx);
2288 if (flags & DETACH_GROUP)
2289 perf_group_detach(event);
2290 list_del_event(event, ctx);
2292 if (!ctx->nr_events && ctx->is_active) {
2294 ctx->rotate_necessary = 0;
2296 WARN_ON_ONCE(cpuctx->task_ctx != ctx);
2297 cpuctx->task_ctx = NULL;
2303 * Remove the event from a task's (or a CPU's) list of events.
2305 * If event->ctx is a cloned context, callers must make sure that
2306 * every task struct that event->ctx->task could possibly point to
2307 * remains valid. This is OK when called from perf_release since
2308 * that only calls us on the top-level context, which can't be a clone.
2309 * When called from perf_event_exit_task, it's OK because the
2310 * context has been detached from its task.
2312 static void perf_remove_from_context(struct perf_event *event, unsigned long flags)
2314 struct perf_event_context *ctx = event->ctx;
2316 lockdep_assert_held(&ctx->mutex);
2318 event_function_call(event, __perf_remove_from_context, (void *)flags);
2321 * The above event_function_call() can NO-OP when it hits
2322 * TASK_TOMBSTONE. In that case we must already have been detached
2323 * from the context (by perf_event_exit_event()) but the grouping
2324 * might still be in-tact.
2326 WARN_ON_ONCE(event->attach_state & PERF_ATTACH_CONTEXT);
2327 if ((flags & DETACH_GROUP) &&
2328 (event->attach_state & PERF_ATTACH_GROUP)) {
2330 * Since in that case we cannot possibly be scheduled, simply
2333 raw_spin_lock_irq(&ctx->lock);
2334 perf_group_detach(event);
2335 raw_spin_unlock_irq(&ctx->lock);
2340 * Cross CPU call to disable a performance event
2342 static void __perf_event_disable(struct perf_event *event,
2343 struct perf_cpu_context *cpuctx,
2344 struct perf_event_context *ctx,
2347 if (event->state < PERF_EVENT_STATE_INACTIVE)
2350 if (ctx->is_active & EVENT_TIME) {
2351 update_context_time(ctx);
2352 update_cgrp_time_from_event(event);
2355 if (event == event->group_leader)
2356 group_sched_out(event, cpuctx, ctx);
2358 event_sched_out(event, cpuctx, ctx);
2360 perf_event_set_state(event, PERF_EVENT_STATE_OFF);
2366 * If event->ctx is a cloned context, callers must make sure that
2367 * every task struct that event->ctx->task could possibly point to
2368 * remains valid. This condition is satisfied when called through
2369 * perf_event_for_each_child or perf_event_for_each because they
2370 * hold the top-level event's child_mutex, so any descendant that
2371 * goes to exit will block in perf_event_exit_event().
2373 * When called from perf_pending_event it's OK because event->ctx
2374 * is the current context on this CPU and preemption is disabled,
2375 * hence we can't get into perf_event_task_sched_out for this context.
2377 static void _perf_event_disable(struct perf_event *event)
2379 struct perf_event_context *ctx = event->ctx;
2381 raw_spin_lock_irq(&ctx->lock);
2382 if (event->state <= PERF_EVENT_STATE_OFF) {
2383 raw_spin_unlock_irq(&ctx->lock);
2386 raw_spin_unlock_irq(&ctx->lock);
2388 event_function_call(event, __perf_event_disable, NULL);
2391 void perf_event_disable_local(struct perf_event *event)
2393 event_function_local(event, __perf_event_disable, NULL);
2397 * Strictly speaking kernel users cannot create groups and therefore this
2398 * interface does not need the perf_event_ctx_lock() magic.
2400 void perf_event_disable(struct perf_event *event)
2402 struct perf_event_context *ctx;
2404 ctx = perf_event_ctx_lock(event);
2405 _perf_event_disable(event);
2406 perf_event_ctx_unlock(event, ctx);
2408 EXPORT_SYMBOL_GPL(perf_event_disable);
2410 void perf_event_disable_inatomic(struct perf_event *event)
2412 WRITE_ONCE(event->pending_disable, smp_processor_id());
2413 /* can fail, see perf_pending_event_disable() */
2414 irq_work_queue(&event->pending);
2417 static void perf_set_shadow_time(struct perf_event *event,
2418 struct perf_event_context *ctx)
2421 * use the correct time source for the time snapshot
2423 * We could get by without this by leveraging the
2424 * fact that to get to this function, the caller
2425 * has most likely already called update_context_time()
2426 * and update_cgrp_time_xx() and thus both timestamp
2427 * are identical (or very close). Given that tstamp is,
2428 * already adjusted for cgroup, we could say that:
2429 * tstamp - ctx->timestamp
2431 * tstamp - cgrp->timestamp.
2433 * Then, in perf_output_read(), the calculation would
2434 * work with no changes because:
2435 * - event is guaranteed scheduled in
2436 * - no scheduled out in between
2437 * - thus the timestamp would be the same
2439 * But this is a bit hairy.
2441 * So instead, we have an explicit cgroup call to remain
2442 * within the time time source all along. We believe it
2443 * is cleaner and simpler to understand.
2445 if (is_cgroup_event(event))
2446 perf_cgroup_set_shadow_time(event, event->tstamp);
2448 event->shadow_ctx_time = event->tstamp - ctx->timestamp;
2451 #define MAX_INTERRUPTS (~0ULL)
2453 static void perf_log_throttle(struct perf_event *event, int enable);
2454 static void perf_log_itrace_start(struct perf_event *event);
2457 event_sched_in(struct perf_event *event,
2458 struct perf_cpu_context *cpuctx,
2459 struct perf_event_context *ctx)
2463 WARN_ON_ONCE(event->ctx != ctx);
2465 lockdep_assert_held(&ctx->lock);
2467 if (event->state <= PERF_EVENT_STATE_OFF)
2470 WRITE_ONCE(event->oncpu, smp_processor_id());
2472 * Order event::oncpu write to happen before the ACTIVE state is
2473 * visible. This allows perf_event_{stop,read}() to observe the correct
2474 * ->oncpu if it sees ACTIVE.
2477 perf_event_set_state(event, PERF_EVENT_STATE_ACTIVE);
2480 * Unthrottle events, since we scheduled we might have missed several
2481 * ticks already, also for a heavily scheduling task there is little
2482 * guarantee it'll get a tick in a timely manner.
2484 if (unlikely(event->hw.interrupts == MAX_INTERRUPTS)) {
2485 perf_log_throttle(event, 1);
2486 event->hw.interrupts = 0;
2489 perf_pmu_disable(event->pmu);
2491 perf_set_shadow_time(event, ctx);
2493 perf_log_itrace_start(event);
2495 if (event->pmu->add(event, PERF_EF_START)) {
2496 perf_event_set_state(event, PERF_EVENT_STATE_INACTIVE);
2502 if (!is_software_event(event))
2503 cpuctx->active_oncpu++;
2504 if (!ctx->nr_active++)
2505 perf_event_ctx_activate(ctx);
2506 if (event->attr.freq && event->attr.sample_freq)
2509 if (event->attr.exclusive)
2510 cpuctx->exclusive = 1;
2513 perf_pmu_enable(event->pmu);
2519 group_sched_in(struct perf_event *group_event,
2520 struct perf_cpu_context *cpuctx,
2521 struct perf_event_context *ctx)
2523 struct perf_event *event, *partial_group = NULL;
2524 struct pmu *pmu = ctx->pmu;
2526 if (group_event->state == PERF_EVENT_STATE_OFF)
2529 pmu->start_txn(pmu, PERF_PMU_TXN_ADD);
2531 if (event_sched_in(group_event, cpuctx, ctx)) {
2532 pmu->cancel_txn(pmu);
2533 perf_mux_hrtimer_restart(cpuctx);
2538 * Schedule in siblings as one group (if any):
2540 for_each_sibling_event(event, group_event) {
2541 if (event_sched_in(event, cpuctx, ctx)) {
2542 partial_group = event;
2547 if (!pmu->commit_txn(pmu))
2552 * Groups can be scheduled in as one unit only, so undo any
2553 * partial group before returning:
2554 * The events up to the failed event are scheduled out normally.
2556 for_each_sibling_event(event, group_event) {
2557 if (event == partial_group)
2560 event_sched_out(event, cpuctx, ctx);
2562 event_sched_out(group_event, cpuctx, ctx);
2564 pmu->cancel_txn(pmu);
2566 perf_mux_hrtimer_restart(cpuctx);
2572 * Work out whether we can put this event group on the CPU now.
2574 static int group_can_go_on(struct perf_event *event,
2575 struct perf_cpu_context *cpuctx,
2579 * Groups consisting entirely of software events can always go on.
2581 if (event->group_caps & PERF_EV_CAP_SOFTWARE)
2584 * If an exclusive group is already on, no other hardware
2587 if (cpuctx->exclusive)
2590 * If this group is exclusive and there are already
2591 * events on the CPU, it can't go on.
2593 if (event->attr.exclusive && cpuctx->active_oncpu)
2596 * Otherwise, try to add it if all previous groups were able
2602 static void add_event_to_ctx(struct perf_event *event,
2603 struct perf_event_context *ctx)
2605 list_add_event(event, ctx);
2606 perf_group_attach(event);
2609 static void ctx_sched_out(struct perf_event_context *ctx,
2610 struct perf_cpu_context *cpuctx,
2611 enum event_type_t event_type);
2613 ctx_sched_in(struct perf_event_context *ctx,
2614 struct perf_cpu_context *cpuctx,
2615 enum event_type_t event_type,
2616 struct task_struct *task);
2618 static void task_ctx_sched_out(struct perf_cpu_context *cpuctx,
2619 struct perf_event_context *ctx,
2620 enum event_type_t event_type)
2622 if (!cpuctx->task_ctx)
2625 if (WARN_ON_ONCE(ctx != cpuctx->task_ctx))
2628 ctx_sched_out(ctx, cpuctx, event_type);
2631 static void perf_event_sched_in(struct perf_cpu_context *cpuctx,
2632 struct perf_event_context *ctx,
2633 struct task_struct *task)
2635 cpu_ctx_sched_in(cpuctx, EVENT_PINNED, task);
2637 ctx_sched_in(ctx, cpuctx, EVENT_PINNED, task);
2638 cpu_ctx_sched_in(cpuctx, EVENT_FLEXIBLE, task);
2640 ctx_sched_in(ctx, cpuctx, EVENT_FLEXIBLE, task);
2644 * We want to maintain the following priority of scheduling:
2645 * - CPU pinned (EVENT_CPU | EVENT_PINNED)
2646 * - task pinned (EVENT_PINNED)
2647 * - CPU flexible (EVENT_CPU | EVENT_FLEXIBLE)
2648 * - task flexible (EVENT_FLEXIBLE).
2650 * In order to avoid unscheduling and scheduling back in everything every
2651 * time an event is added, only do it for the groups of equal priority and
2654 * This can be called after a batch operation on task events, in which case
2655 * event_type is a bit mask of the types of events involved. For CPU events,
2656 * event_type is only either EVENT_PINNED or EVENT_FLEXIBLE.
2658 static void ctx_resched(struct perf_cpu_context *cpuctx,
2659 struct perf_event_context *task_ctx,
2660 enum event_type_t event_type)
2662 enum event_type_t ctx_event_type;
2663 bool cpu_event = !!(event_type & EVENT_CPU);
2666 * If pinned groups are involved, flexible groups also need to be
2669 if (event_type & EVENT_PINNED)
2670 event_type |= EVENT_FLEXIBLE;
2672 ctx_event_type = event_type & EVENT_ALL;
2674 perf_pmu_disable(cpuctx->ctx.pmu);
2676 task_ctx_sched_out(cpuctx, task_ctx, event_type);
2679 * Decide which cpu ctx groups to schedule out based on the types
2680 * of events that caused rescheduling:
2681 * - EVENT_CPU: schedule out corresponding groups;
2682 * - EVENT_PINNED task events: schedule out EVENT_FLEXIBLE groups;
2683 * - otherwise, do nothing more.
2686 cpu_ctx_sched_out(cpuctx, ctx_event_type);
2687 else if (ctx_event_type & EVENT_PINNED)
2688 cpu_ctx_sched_out(cpuctx, EVENT_FLEXIBLE);
2690 perf_event_sched_in(cpuctx, task_ctx, current);
2691 perf_pmu_enable(cpuctx->ctx.pmu);
2694 void perf_pmu_resched(struct pmu *pmu)
2696 struct perf_cpu_context *cpuctx = this_cpu_ptr(pmu->pmu_cpu_context);
2697 struct perf_event_context *task_ctx = cpuctx->task_ctx;
2699 perf_ctx_lock(cpuctx, task_ctx);
2700 ctx_resched(cpuctx, task_ctx, EVENT_ALL|EVENT_CPU);
2701 perf_ctx_unlock(cpuctx, task_ctx);
2705 * Cross CPU call to install and enable a performance event
2707 * Very similar to remote_function() + event_function() but cannot assume that
2708 * things like ctx->is_active and cpuctx->task_ctx are set.
2710 static int __perf_install_in_context(void *info)
2712 struct perf_event *event = info;
2713 struct perf_event_context *ctx = event->ctx;
2714 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
2715 struct perf_event_context *task_ctx = cpuctx->task_ctx;
2716 bool reprogram = true;
2719 raw_spin_lock(&cpuctx->ctx.lock);
2721 raw_spin_lock(&ctx->lock);
2724 reprogram = (ctx->task == current);
2727 * If the task is running, it must be running on this CPU,
2728 * otherwise we cannot reprogram things.
2730 * If its not running, we don't care, ctx->lock will
2731 * serialize against it becoming runnable.
2733 if (task_curr(ctx->task) && !reprogram) {
2738 WARN_ON_ONCE(reprogram && cpuctx->task_ctx && cpuctx->task_ctx != ctx);
2739 } else if (task_ctx) {
2740 raw_spin_lock(&task_ctx->lock);
2743 #ifdef CONFIG_CGROUP_PERF
2744 if (is_cgroup_event(event)) {
2746 * If the current cgroup doesn't match the event's
2747 * cgroup, we should not try to schedule it.
2749 struct perf_cgroup *cgrp = perf_cgroup_from_task(current, ctx);
2750 reprogram = cgroup_is_descendant(cgrp->css.cgroup,
2751 event->cgrp->css.cgroup);
2756 ctx_sched_out(ctx, cpuctx, EVENT_TIME);
2757 add_event_to_ctx(event, ctx);
2758 ctx_resched(cpuctx, task_ctx, get_event_type(event));
2760 add_event_to_ctx(event, ctx);
2764 perf_ctx_unlock(cpuctx, task_ctx);
2769 static bool exclusive_event_installable(struct perf_event *event,
2770 struct perf_event_context *ctx);
2773 * Attach a performance event to a context.
2775 * Very similar to event_function_call, see comment there.
2778 perf_install_in_context(struct perf_event_context *ctx,
2779 struct perf_event *event,
2782 struct task_struct *task = READ_ONCE(ctx->task);
2784 lockdep_assert_held(&ctx->mutex);
2786 WARN_ON_ONCE(!exclusive_event_installable(event, ctx));
2788 if (event->cpu != -1)
2792 * Ensures that if we can observe event->ctx, both the event and ctx
2793 * will be 'complete'. See perf_iterate_sb_cpu().
2795 smp_store_release(&event->ctx, ctx);
2798 * perf_event_attr::disabled events will not run and can be initialized
2799 * without IPI. Except when this is the first event for the context, in
2800 * that case we need the magic of the IPI to set ctx->is_active.
2802 * The IOC_ENABLE that is sure to follow the creation of a disabled
2803 * event will issue the IPI and reprogram the hardware.
2805 if (__perf_effective_state(event) == PERF_EVENT_STATE_OFF && ctx->nr_events) {
2806 raw_spin_lock_irq(&ctx->lock);
2807 if (ctx->task == TASK_TOMBSTONE) {
2808 raw_spin_unlock_irq(&ctx->lock);
2811 add_event_to_ctx(event, ctx);
2812 raw_spin_unlock_irq(&ctx->lock);
2817 cpu_function_call(cpu, __perf_install_in_context, event);
2822 * Should not happen, we validate the ctx is still alive before calling.
2824 if (WARN_ON_ONCE(task == TASK_TOMBSTONE))
2828 * Installing events is tricky because we cannot rely on ctx->is_active
2829 * to be set in case this is the nr_events 0 -> 1 transition.
2831 * Instead we use task_curr(), which tells us if the task is running.
2832 * However, since we use task_curr() outside of rq::lock, we can race
2833 * against the actual state. This means the result can be wrong.
2835 * If we get a false positive, we retry, this is harmless.
2837 * If we get a false negative, things are complicated. If we are after
2838 * perf_event_context_sched_in() ctx::lock will serialize us, and the
2839 * value must be correct. If we're before, it doesn't matter since
2840 * perf_event_context_sched_in() will program the counter.
2842 * However, this hinges on the remote context switch having observed
2843 * our task->perf_event_ctxp[] store, such that it will in fact take
2844 * ctx::lock in perf_event_context_sched_in().
2846 * We do this by task_function_call(), if the IPI fails to hit the task
2847 * we know any future context switch of task must see the
2848 * perf_event_ctpx[] store.
2852 * This smp_mb() orders the task->perf_event_ctxp[] store with the
2853 * task_cpu() load, such that if the IPI then does not find the task
2854 * running, a future context switch of that task must observe the
2859 if (!task_function_call(task, __perf_install_in_context, event))
2862 raw_spin_lock_irq(&ctx->lock);
2864 if (WARN_ON_ONCE(task == TASK_TOMBSTONE)) {
2866 * Cannot happen because we already checked above (which also
2867 * cannot happen), and we hold ctx->mutex, which serializes us
2868 * against perf_event_exit_task_context().
2870 raw_spin_unlock_irq(&ctx->lock);
2874 * If the task is not running, ctx->lock will avoid it becoming so,
2875 * thus we can safely install the event.
2877 if (task_curr(task)) {
2878 raw_spin_unlock_irq(&ctx->lock);
2881 add_event_to_ctx(event, ctx);
2882 raw_spin_unlock_irq(&ctx->lock);
2886 * Cross CPU call to enable a performance event
2888 static void __perf_event_enable(struct perf_event *event,
2889 struct perf_cpu_context *cpuctx,
2890 struct perf_event_context *ctx,
2893 struct perf_event *leader = event->group_leader;
2894 struct perf_event_context *task_ctx;
2896 if (event->state >= PERF_EVENT_STATE_INACTIVE ||
2897 event->state <= PERF_EVENT_STATE_ERROR)
2901 ctx_sched_out(ctx, cpuctx, EVENT_TIME);
2903 perf_event_set_state(event, PERF_EVENT_STATE_INACTIVE);
2905 if (!ctx->is_active)
2908 if (!event_filter_match(event)) {
2909 ctx_sched_in(ctx, cpuctx, EVENT_TIME, current);
2914 * If the event is in a group and isn't the group leader,
2915 * then don't put it on unless the group is on.
2917 if (leader != event && leader->state != PERF_EVENT_STATE_ACTIVE) {
2918 ctx_sched_in(ctx, cpuctx, EVENT_TIME, current);
2922 task_ctx = cpuctx->task_ctx;
2924 WARN_ON_ONCE(task_ctx != ctx);
2926 ctx_resched(cpuctx, task_ctx, get_event_type(event));
2932 * If event->ctx is a cloned context, callers must make sure that
2933 * every task struct that event->ctx->task could possibly point to
2934 * remains valid. This condition is satisfied when called through
2935 * perf_event_for_each_child or perf_event_for_each as described
2936 * for perf_event_disable.
2938 static void _perf_event_enable(struct perf_event *event)
2940 struct perf_event_context *ctx = event->ctx;
2942 raw_spin_lock_irq(&ctx->lock);
2943 if (event->state >= PERF_EVENT_STATE_INACTIVE ||
2944 event->state < PERF_EVENT_STATE_ERROR) {
2945 raw_spin_unlock_irq(&ctx->lock);
2950 * If the event is in error state, clear that first.
2952 * That way, if we see the event in error state below, we know that it
2953 * has gone back into error state, as distinct from the task having
2954 * been scheduled away before the cross-call arrived.
2956 if (event->state == PERF_EVENT_STATE_ERROR)
2957 event->state = PERF_EVENT_STATE_OFF;
2958 raw_spin_unlock_irq(&ctx->lock);
2960 event_function_call(event, __perf_event_enable, NULL);
2964 * See perf_event_disable();
2966 void perf_event_enable(struct perf_event *event)
2968 struct perf_event_context *ctx;
2970 ctx = perf_event_ctx_lock(event);
2971 _perf_event_enable(event);
2972 perf_event_ctx_unlock(event, ctx);
2974 EXPORT_SYMBOL_GPL(perf_event_enable);
2976 struct stop_event_data {
2977 struct perf_event *event;
2978 unsigned int restart;
2981 static int __perf_event_stop(void *info)
2983 struct stop_event_data *sd = info;
2984 struct perf_event *event = sd->event;
2986 /* if it's already INACTIVE, do nothing */
2987 if (READ_ONCE(event->state) != PERF_EVENT_STATE_ACTIVE)
2990 /* matches smp_wmb() in event_sched_in() */
2994 * There is a window with interrupts enabled before we get here,
2995 * so we need to check again lest we try to stop another CPU's event.
2997 if (READ_ONCE(event->oncpu) != smp_processor_id())
3000 event->pmu->stop(event, PERF_EF_UPDATE);
3003 * May race with the actual stop (through perf_pmu_output_stop()),
3004 * but it is only used for events with AUX ring buffer, and such
3005 * events will refuse to restart because of rb::aux_mmap_count==0,
3006 * see comments in perf_aux_output_begin().
3008 * Since this is happening on an event-local CPU, no trace is lost
3012 event->pmu->start(event, 0);
3017 static int perf_event_stop(struct perf_event *event, int restart)
3019 struct stop_event_data sd = {
3026 if (READ_ONCE(event->state) != PERF_EVENT_STATE_ACTIVE)
3029 /* matches smp_wmb() in event_sched_in() */
3033 * We only want to restart ACTIVE events, so if the event goes
3034 * inactive here (event->oncpu==-1), there's nothing more to do;
3035 * fall through with ret==-ENXIO.
3037 ret = cpu_function_call(READ_ONCE(event->oncpu),
3038 __perf_event_stop, &sd);
3039 } while (ret == -EAGAIN);
3045 * In order to contain the amount of racy and tricky in the address filter
3046 * configuration management, it is a two part process:
3048 * (p1) when userspace mappings change as a result of (1) or (2) or (3) below,
3049 * we update the addresses of corresponding vmas in
3050 * event::addr_filter_ranges array and bump the event::addr_filters_gen;
3051 * (p2) when an event is scheduled in (pmu::add), it calls
3052 * perf_event_addr_filters_sync() which calls pmu::addr_filters_sync()
3053 * if the generation has changed since the previous call.
3055 * If (p1) happens while the event is active, we restart it to force (p2).
3057 * (1) perf_addr_filters_apply(): adjusting filters' offsets based on
3058 * pre-existing mappings, called once when new filters arrive via SET_FILTER
3060 * (2) perf_addr_filters_adjust(): adjusting filters' offsets based on newly
3061 * registered mapping, called for every new mmap(), with mm::mmap_sem down
3063 * (3) perf_event_addr_filters_exec(): clearing filters' offsets in the process
3066 void perf_event_addr_filters_sync(struct perf_event *event)
3068 struct perf_addr_filters_head *ifh = perf_event_addr_filters(event);
3070 if (!has_addr_filter(event))
3073 raw_spin_lock(&ifh->lock);
3074 if (event->addr_filters_gen != event->hw.addr_filters_gen) {
3075 event->pmu->addr_filters_sync(event);
3076 event->hw.addr_filters_gen = event->addr_filters_gen;
3078 raw_spin_unlock(&ifh->lock);
3080 EXPORT_SYMBOL_GPL(perf_event_addr_filters_sync);
3082 static int _perf_event_refresh(struct perf_event *event, int refresh)
3085 * not supported on inherited events
3087 if (event->attr.inherit || !is_sampling_event(event))
3090 atomic_add(refresh, &event->event_limit);
3091 _perf_event_enable(event);
3097 * See perf_event_disable()
3099 int perf_event_refresh(struct perf_event *event, int refresh)
3101 struct perf_event_context *ctx;
3104 ctx = perf_event_ctx_lock(event);
3105 ret = _perf_event_refresh(event, refresh);
3106 perf_event_ctx_unlock(event, ctx);
3110 EXPORT_SYMBOL_GPL(perf_event_refresh);
3112 static int perf_event_modify_breakpoint(struct perf_event *bp,
3113 struct perf_event_attr *attr)
3117 _perf_event_disable(bp);
3119 err = modify_user_hw_breakpoint_check(bp, attr, true);
3121 if (!bp->attr.disabled)
3122 _perf_event_enable(bp);
3127 static int perf_event_modify_attr(struct perf_event *event,
3128 struct perf_event_attr *attr)
3130 if (event->attr.type != attr->type)
3133 switch (event->attr.type) {
3134 case PERF_TYPE_BREAKPOINT:
3135 return perf_event_modify_breakpoint(event, attr);
3137 /* Place holder for future additions. */
3142 static void ctx_sched_out(struct perf_event_context *ctx,
3143 struct perf_cpu_context *cpuctx,
3144 enum event_type_t event_type)
3146 struct perf_event *event, *tmp;
3147 int is_active = ctx->is_active;
3149 lockdep_assert_held(&ctx->lock);
3151 if (likely(!ctx->nr_events)) {
3153 * See __perf_remove_from_context().
3155 WARN_ON_ONCE(ctx->is_active);
3157 WARN_ON_ONCE(cpuctx->task_ctx);
3161 ctx->is_active &= ~event_type;
3162 if (!(ctx->is_active & EVENT_ALL))
3166 WARN_ON_ONCE(cpuctx->task_ctx != ctx);
3167 if (!ctx->is_active)
3168 cpuctx->task_ctx = NULL;
3172 * Always update time if it was set; not only when it changes.
3173 * Otherwise we can 'forget' to update time for any but the last
3174 * context we sched out. For example:
3176 * ctx_sched_out(.event_type = EVENT_FLEXIBLE)
3177 * ctx_sched_out(.event_type = EVENT_PINNED)
3179 * would only update time for the pinned events.
3181 if (is_active & EVENT_TIME) {
3182 /* update (and stop) ctx time */
3183 update_context_time(ctx);
3184 update_cgrp_time_from_cpuctx(cpuctx);
3187 is_active ^= ctx->is_active; /* changed bits */
3189 if (!ctx->nr_active || !(is_active & EVENT_ALL))
3192 perf_pmu_disable(ctx->pmu);
3193 if (is_active & EVENT_PINNED) {
3194 list_for_each_entry_safe(event, tmp, &ctx->pinned_active, active_list)
3195 group_sched_out(event, cpuctx, ctx);
3198 if (is_active & EVENT_FLEXIBLE) {
3199 list_for_each_entry_safe(event, tmp, &ctx->flexible_active, active_list)
3200 group_sched_out(event, cpuctx, ctx);
3203 * Since we cleared EVENT_FLEXIBLE, also clear
3204 * rotate_necessary, is will be reset by
3205 * ctx_flexible_sched_in() when needed.
3207 ctx->rotate_necessary = 0;
3209 perf_pmu_enable(ctx->pmu);
3213 * Test whether two contexts are equivalent, i.e. whether they have both been
3214 * cloned from the same version of the same context.
3216 * Equivalence is measured using a generation number in the context that is
3217 * incremented on each modification to it; see unclone_ctx(), list_add_event()
3218 * and list_del_event().
3220 static int context_equiv(struct perf_event_context *ctx1,
3221 struct perf_event_context *ctx2)
3223 lockdep_assert_held(&ctx1->lock);
3224 lockdep_assert_held(&ctx2->lock);
3226 /* Pinning disables the swap optimization */
3227 if (ctx1->pin_count || ctx2->pin_count)
3230 /* If ctx1 is the parent of ctx2 */
3231 if (ctx1 == ctx2->parent_ctx && ctx1->generation == ctx2->parent_gen)
3234 /* If ctx2 is the parent of ctx1 */
3235 if (ctx1->parent_ctx == ctx2 && ctx1->parent_gen == ctx2->generation)
3239 * If ctx1 and ctx2 have the same parent; we flatten the parent
3240 * hierarchy, see perf_event_init_context().
3242 if (ctx1->parent_ctx && ctx1->parent_ctx == ctx2->parent_ctx &&
3243 ctx1->parent_gen == ctx2->parent_gen)
3250 static void __perf_event_sync_stat(struct perf_event *event,
3251 struct perf_event *next_event)
3255 if (!event->attr.inherit_stat)
3259 * Update the event value, we cannot use perf_event_read()
3260 * because we're in the middle of a context switch and have IRQs
3261 * disabled, which upsets smp_call_function_single(), however
3262 * we know the event must be on the current CPU, therefore we
3263 * don't need to use it.
3265 if (event->state == PERF_EVENT_STATE_ACTIVE)
3266 event->pmu->read(event);
3268 perf_event_update_time(event);
3271 * In order to keep per-task stats reliable we need to flip the event
3272 * values when we flip the contexts.
3274 value = local64_read(&next_event->count);
3275 value = local64_xchg(&event->count, value);
3276 local64_set(&next_event->count, value);
3278 swap(event->total_time_enabled, next_event->total_time_enabled);
3279 swap(event->total_time_running, next_event->total_time_running);
3282 * Since we swizzled the values, update the user visible data too.
3284 perf_event_update_userpage(event);
3285 perf_event_update_userpage(next_event);
3288 static void perf_event_sync_stat(struct perf_event_context *ctx,
3289 struct perf_event_context *next_ctx)
3291 struct perf_event *event, *next_event;
3296 update_context_time(ctx);
3298 event = list_first_entry(&ctx->event_list,
3299 struct perf_event, event_entry);
3301 next_event = list_first_entry(&next_ctx->event_list,
3302 struct perf_event, event_entry);
3304 while (&event->event_entry != &ctx->event_list &&
3305 &next_event->event_entry != &next_ctx->event_list) {
3307 __perf_event_sync_stat(event, next_event);
3309 event = list_next_entry(event, event_entry);
3310 next_event = list_next_entry(next_event, event_entry);
3314 static void perf_event_context_sched_out(struct task_struct *task, int ctxn,
3315 struct task_struct *next)
3317 struct perf_event_context *ctx = task->perf_event_ctxp[ctxn];
3318 struct perf_event_context *next_ctx;
3319 struct perf_event_context *parent, *next_parent;
3320 struct perf_cpu_context *cpuctx;
3326 cpuctx = __get_cpu_context(ctx);
3327 if (!cpuctx->task_ctx)
3331 next_ctx = next->perf_event_ctxp[ctxn];
3335 parent = rcu_dereference(ctx->parent_ctx);
3336 next_parent = rcu_dereference(next_ctx->parent_ctx);
3338 /* If neither context have a parent context; they cannot be clones. */
3339 if (!parent && !next_parent)
3342 if (next_parent == ctx || next_ctx == parent || next_parent == parent) {
3344 * Looks like the two contexts are clones, so we might be
3345 * able to optimize the context switch. We lock both
3346 * contexts and check that they are clones under the
3347 * lock (including re-checking that neither has been
3348 * uncloned in the meantime). It doesn't matter which
3349 * order we take the locks because no other cpu could
3350 * be trying to lock both of these tasks.
3352 raw_spin_lock(&ctx->lock);
3353 raw_spin_lock_nested(&next_ctx->lock, SINGLE_DEPTH_NESTING);
3354 if (context_equiv(ctx, next_ctx)) {
3355 struct pmu *pmu = ctx->pmu;
3357 WRITE_ONCE(ctx->task, next);
3358 WRITE_ONCE(next_ctx->task, task);
3361 * PMU specific parts of task perf context can require
3362 * additional synchronization. As an example of such
3363 * synchronization see implementation details of Intel
3364 * LBR call stack data profiling;
3366 if (pmu->swap_task_ctx)
3367 pmu->swap_task_ctx(ctx, next_ctx);
3369 swap(ctx->task_ctx_data, next_ctx->task_ctx_data);
3372 * RCU_INIT_POINTER here is safe because we've not
3373 * modified the ctx and the above modification of
3374 * ctx->task and ctx->task_ctx_data are immaterial
3375 * since those values are always verified under
3376 * ctx->lock which we're now holding.
3378 RCU_INIT_POINTER(task->perf_event_ctxp[ctxn], next_ctx);
3379 RCU_INIT_POINTER(next->perf_event_ctxp[ctxn], ctx);
3383 perf_event_sync_stat(ctx, next_ctx);
3385 raw_spin_unlock(&next_ctx->lock);
3386 raw_spin_unlock(&ctx->lock);
3392 raw_spin_lock(&ctx->lock);
3393 task_ctx_sched_out(cpuctx, ctx, EVENT_ALL);
3394 raw_spin_unlock(&ctx->lock);
3398 static DEFINE_PER_CPU(struct list_head, sched_cb_list);
3400 void perf_sched_cb_dec(struct pmu *pmu)
3402 struct perf_cpu_context *cpuctx = this_cpu_ptr(pmu->pmu_cpu_context);
3404 this_cpu_dec(perf_sched_cb_usages);
3406 if (!--cpuctx->sched_cb_usage)
3407 list_del(&cpuctx->sched_cb_entry);
3411 void perf_sched_cb_inc(struct pmu *pmu)
3413 struct perf_cpu_context *cpuctx = this_cpu_ptr(pmu->pmu_cpu_context);
3415 if (!cpuctx->sched_cb_usage++)
3416 list_add(&cpuctx->sched_cb_entry, this_cpu_ptr(&sched_cb_list));
3418 this_cpu_inc(perf_sched_cb_usages);
3422 * This function provides the context switch callback to the lower code
3423 * layer. It is invoked ONLY when the context switch callback is enabled.
3425 * This callback is relevant even to per-cpu events; for example multi event
3426 * PEBS requires this to provide PID/TID information. This requires we flush
3427 * all queued PEBS records before we context switch to a new task.
3429 static void perf_pmu_sched_task(struct task_struct *prev,
3430 struct task_struct *next,
3433 struct perf_cpu_context *cpuctx;
3439 list_for_each_entry(cpuctx, this_cpu_ptr(&sched_cb_list), sched_cb_entry) {
3440 pmu = cpuctx->ctx.pmu; /* software PMUs will not have sched_task */
3442 if (WARN_ON_ONCE(!pmu->sched_task))
3445 perf_ctx_lock(cpuctx, cpuctx->task_ctx);
3446 perf_pmu_disable(pmu);
3448 pmu->sched_task(cpuctx->task_ctx, sched_in);
3450 perf_pmu_enable(pmu);
3451 perf_ctx_unlock(cpuctx, cpuctx->task_ctx);
3455 static void perf_event_switch(struct task_struct *task,
3456 struct task_struct *next_prev, bool sched_in);
3458 #define for_each_task_context_nr(ctxn) \
3459 for ((ctxn) = 0; (ctxn) < perf_nr_task_contexts; (ctxn)++)
3462 * Called from scheduler to remove the events of the current task,
3463 * with interrupts disabled.
3465 * We stop each event and update the event value in event->count.
3467 * This does not protect us against NMI, but disable()
3468 * sets the disabled bit in the control field of event _before_
3469 * accessing the event control register. If a NMI hits, then it will
3470 * not restart the event.
3472 void __perf_event_task_sched_out(struct task_struct *task,
3473 struct task_struct *next)
3477 if (__this_cpu_read(perf_sched_cb_usages))
3478 perf_pmu_sched_task(task, next, false);
3480 if (atomic_read(&nr_switch_events))
3481 perf_event_switch(task, next, false);
3483 for_each_task_context_nr(ctxn)
3484 perf_event_context_sched_out(task, ctxn, next);
3487 * if cgroup events exist on this CPU, then we need
3488 * to check if we have to switch out PMU state.
3489 * cgroup event are system-wide mode only
3491 if (atomic_read(this_cpu_ptr(&perf_cgroup_events)))
3492 perf_cgroup_sched_out(task, next);
3496 * Called with IRQs disabled
3498 static void cpu_ctx_sched_out(struct perf_cpu_context *cpuctx,
3499 enum event_type_t event_type)
3501 ctx_sched_out(&cpuctx->ctx, cpuctx, event_type);
3504 static bool perf_less_group_idx(const void *l, const void *r)
3506 const struct perf_event *le = l, *re = r;
3508 return le->group_index < re->group_index;
3511 static void swap_ptr(void *l, void *r)
3513 void **lp = l, **rp = r;
3518 static const struct min_heap_callbacks perf_min_heap = {
3519 .elem_size = sizeof(struct perf_event *),
3520 .less = perf_less_group_idx,
3524 static void __heap_add(struct min_heap *heap, struct perf_event *event)
3526 struct perf_event **itrs = heap->data;
3529 itrs[heap->nr] = event;
3534 static noinline int visit_groups_merge(struct perf_cpu_context *cpuctx,
3535 struct perf_event_groups *groups, int cpu,
3536 int (*func)(struct perf_event *, void *),
3539 #ifdef CONFIG_CGROUP_PERF
3540 struct cgroup_subsys_state *css = NULL;
3542 /* Space for per CPU and/or any CPU event iterators. */
3543 struct perf_event *itrs[2];
3544 struct min_heap event_heap;
3545 struct perf_event **evt;
3549 event_heap = (struct min_heap){
3550 .data = cpuctx->heap,
3552 .size = cpuctx->heap_size,
3555 lockdep_assert_held(&cpuctx->ctx.lock);
3557 #ifdef CONFIG_CGROUP_PERF
3559 css = &cpuctx->cgrp->css;
3562 event_heap = (struct min_heap){
3565 .size = ARRAY_SIZE(itrs),
3567 /* Events not within a CPU context may be on any CPU. */
3568 __heap_add(&event_heap, perf_event_groups_first(groups, -1, NULL));
3570 evt = event_heap.data;
3572 __heap_add(&event_heap, perf_event_groups_first(groups, cpu, NULL));
3574 #ifdef CONFIG_CGROUP_PERF
3575 for (; css; css = css->parent)
3576 __heap_add(&event_heap, perf_event_groups_first(groups, cpu, css->cgroup));
3579 min_heapify_all(&event_heap, &perf_min_heap);
3581 while (event_heap.nr) {
3582 ret = func(*evt, data);
3586 *evt = perf_event_groups_next(*evt);
3588 min_heapify(&event_heap, 0, &perf_min_heap);
3590 min_heap_pop(&event_heap, &perf_min_heap);
3596 static int merge_sched_in(struct perf_event *event, void *data)
3598 struct perf_event_context *ctx = event->ctx;
3599 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
3600 int *can_add_hw = data;
3602 if (event->state <= PERF_EVENT_STATE_OFF)
3605 if (!event_filter_match(event))
3608 if (group_can_go_on(event, cpuctx, *can_add_hw)) {
3609 if (!group_sched_in(event, cpuctx, ctx))
3610 list_add_tail(&event->active_list, get_event_list(event));
3613 if (event->state == PERF_EVENT_STATE_INACTIVE) {
3614 if (event->attr.pinned)
3615 perf_event_set_state(event, PERF_EVENT_STATE_ERROR);
3618 ctx->rotate_necessary = 1;
3625 ctx_pinned_sched_in(struct perf_event_context *ctx,
3626 struct perf_cpu_context *cpuctx)
3630 if (ctx != &cpuctx->ctx)
3633 visit_groups_merge(cpuctx, &ctx->pinned_groups,
3635 merge_sched_in, &can_add_hw);
3639 ctx_flexible_sched_in(struct perf_event_context *ctx,
3640 struct perf_cpu_context *cpuctx)
3644 if (ctx != &cpuctx->ctx)
3647 visit_groups_merge(cpuctx, &ctx->flexible_groups,
3649 merge_sched_in, &can_add_hw);
3653 ctx_sched_in(struct perf_event_context *ctx,
3654 struct perf_cpu_context *cpuctx,
3655 enum event_type_t event_type,
3656 struct task_struct *task)
3658 int is_active = ctx->is_active;
3661 lockdep_assert_held(&ctx->lock);
3663 if (likely(!ctx->nr_events))
3666 ctx->is_active |= (event_type | EVENT_TIME);
3669 cpuctx->task_ctx = ctx;
3671 WARN_ON_ONCE(cpuctx->task_ctx != ctx);
3674 is_active ^= ctx->is_active; /* changed bits */
3676 if (is_active & EVENT_TIME) {
3677 /* start ctx time */
3679 ctx->timestamp = now;
3680 perf_cgroup_set_timestamp(task, ctx);
3684 * First go through the list and put on any pinned groups
3685 * in order to give them the best chance of going on.
3687 if (is_active & EVENT_PINNED)
3688 ctx_pinned_sched_in(ctx, cpuctx);
3690 /* Then walk through the lower prio flexible groups */
3691 if (is_active & EVENT_FLEXIBLE)
3692 ctx_flexible_sched_in(ctx, cpuctx);
3695 static void cpu_ctx_sched_in(struct perf_cpu_context *cpuctx,
3696 enum event_type_t event_type,
3697 struct task_struct *task)
3699 struct perf_event_context *ctx = &cpuctx->ctx;
3701 ctx_sched_in(ctx, cpuctx, event_type, task);
3704 static void perf_event_context_sched_in(struct perf_event_context *ctx,
3705 struct task_struct *task)
3707 struct perf_cpu_context *cpuctx;
3709 cpuctx = __get_cpu_context(ctx);
3710 if (cpuctx->task_ctx == ctx)
3713 perf_ctx_lock(cpuctx, ctx);
3715 * We must check ctx->nr_events while holding ctx->lock, such
3716 * that we serialize against perf_install_in_context().
3718 if (!ctx->nr_events)
3721 perf_pmu_disable(ctx->pmu);
3723 * We want to keep the following priority order:
3724 * cpu pinned (that don't need to move), task pinned,
3725 * cpu flexible, task flexible.
3727 * However, if task's ctx is not carrying any pinned
3728 * events, no need to flip the cpuctx's events around.
3730 if (!RB_EMPTY_ROOT(&ctx->pinned_groups.tree))
3731 cpu_ctx_sched_out(cpuctx, EVENT_FLEXIBLE);
3732 perf_event_sched_in(cpuctx, ctx, task);
3733 perf_pmu_enable(ctx->pmu);
3736 perf_ctx_unlock(cpuctx, ctx);
3740 * Called from scheduler to add the events of the current task
3741 * with interrupts disabled.
3743 * We restore the event value and then enable it.
3745 * This does not protect us against NMI, but enable()
3746 * sets the enabled bit in the control field of event _before_
3747 * accessing the event control register. If a NMI hits, then it will
3748 * keep the event running.
3750 void __perf_event_task_sched_in(struct task_struct *prev,
3751 struct task_struct *task)
3753 struct perf_event_context *ctx;
3757 * If cgroup events exist on this CPU, then we need to check if we have
3758 * to switch in PMU state; cgroup event are system-wide mode only.
3760 * Since cgroup events are CPU events, we must schedule these in before
3761 * we schedule in the task events.
3763 if (atomic_read(this_cpu_ptr(&perf_cgroup_events)))
3764 perf_cgroup_sched_in(prev, task);
3766 for_each_task_context_nr(ctxn) {
3767 ctx = task->perf_event_ctxp[ctxn];
3771 perf_event_context_sched_in(ctx, task);
3774 if (atomic_read(&nr_switch_events))
3775 perf_event_switch(task, prev, true);
3777 if (__this_cpu_read(perf_sched_cb_usages))
3778 perf_pmu_sched_task(prev, task, true);
3781 static u64 perf_calculate_period(struct perf_event *event, u64 nsec, u64 count)
3783 u64 frequency = event->attr.sample_freq;
3784 u64 sec = NSEC_PER_SEC;
3785 u64 divisor, dividend;
3787 int count_fls, nsec_fls, frequency_fls, sec_fls;
3789 count_fls = fls64(count);
3790 nsec_fls = fls64(nsec);
3791 frequency_fls = fls64(frequency);
3795 * We got @count in @nsec, with a target of sample_freq HZ
3796 * the target period becomes:
3799 * period = -------------------
3800 * @nsec * sample_freq
3805 * Reduce accuracy by one bit such that @a and @b converge
3806 * to a similar magnitude.
3808 #define REDUCE_FLS(a, b) \
3810 if (a##_fls > b##_fls) { \
3820 * Reduce accuracy until either term fits in a u64, then proceed with
3821 * the other, so that finally we can do a u64/u64 division.
3823 while (count_fls + sec_fls > 64 && nsec_fls + frequency_fls > 64) {
3824 REDUCE_FLS(nsec, frequency);
3825 REDUCE_FLS(sec, count);
3828 if (count_fls + sec_fls > 64) {
3829 divisor = nsec * frequency;
3831 while (count_fls + sec_fls > 64) {
3832 REDUCE_FLS(count, sec);
3836 dividend = count * sec;
3838 dividend = count * sec;
3840 while (nsec_fls + frequency_fls > 64) {
3841 REDUCE_FLS(nsec, frequency);
3845 divisor = nsec * frequency;
3851 return div64_u64(dividend, divisor);
3854 static DEFINE_PER_CPU(int, perf_throttled_count);
3855 static DEFINE_PER_CPU(u64, perf_throttled_seq);
3857 static void perf_adjust_period(struct perf_event *event, u64 nsec, u64 count, bool disable)
3859 struct hw_perf_event *hwc = &event->hw;
3860 s64 period, sample_period;
3863 period = perf_calculate_period(event, nsec, count);
3865 delta = (s64)(period - hwc->sample_period);
3866 delta = (delta + 7) / 8; /* low pass filter */
3868 sample_period = hwc->sample_period + delta;
3873 hwc->sample_period = sample_period;
3875 if (local64_read(&hwc->period_left) > 8*sample_period) {
3877 event->pmu->stop(event, PERF_EF_UPDATE);
3879 local64_set(&hwc->period_left, 0);
3882 event->pmu->start(event, PERF_EF_RELOAD);
3887 * combine freq adjustment with unthrottling to avoid two passes over the
3888 * events. At the same time, make sure, having freq events does not change
3889 * the rate of unthrottling as that would introduce bias.
3891 static void perf_adjust_freq_unthr_context(struct perf_event_context *ctx,
3894 struct perf_event *event;
3895 struct hw_perf_event *hwc;
3896 u64 now, period = TICK_NSEC;
3900 * only need to iterate over all events iff:
3901 * - context have events in frequency mode (needs freq adjust)
3902 * - there are events to unthrottle on this cpu
3904 if (!(ctx->nr_freq || needs_unthr))
3907 raw_spin_lock(&ctx->lock);
3908 perf_pmu_disable(ctx->pmu);
3910 list_for_each_entry_rcu(event, &ctx->event_list, event_entry) {
3911 if (event->state != PERF_EVENT_STATE_ACTIVE)
3914 if (!event_filter_match(event))
3917 perf_pmu_disable(event->pmu);
3921 if (hwc->interrupts == MAX_INTERRUPTS) {
3922 hwc->interrupts = 0;
3923 perf_log_throttle(event, 1);
3924 event->pmu->start(event, 0);
3927 if (!event->attr.freq || !event->attr.sample_freq)
3931 * stop the event and update event->count
3933 event->pmu->stop(event, PERF_EF_UPDATE);
3935 now = local64_read(&event->count);
3936 delta = now - hwc->freq_count_stamp;
3937 hwc->freq_count_stamp = now;
3941 * reload only if value has changed
3942 * we have stopped the event so tell that
3943 * to perf_adjust_period() to avoid stopping it
3947 perf_adjust_period(event, period, delta, false);
3949 event->pmu->start(event, delta > 0 ? PERF_EF_RELOAD : 0);
3951 perf_pmu_enable(event->pmu);
3954 perf_pmu_enable(ctx->pmu);
3955 raw_spin_unlock(&ctx->lock);
3959 * Move @event to the tail of the @ctx's elegible events.
3961 static void rotate_ctx(struct perf_event_context *ctx, struct perf_event *event)
3964 * Rotate the first entry last of non-pinned groups. Rotation might be
3965 * disabled by the inheritance code.
3967 if (ctx->rotate_disable)
3970 perf_event_groups_delete(&ctx->flexible_groups, event);
3971 perf_event_groups_insert(&ctx->flexible_groups, event);
3974 /* pick an event from the flexible_groups to rotate */
3975 static inline struct perf_event *
3976 ctx_event_to_rotate(struct perf_event_context *ctx)
3978 struct perf_event *event;
3980 /* pick the first active flexible event */
3981 event = list_first_entry_or_null(&ctx->flexible_active,
3982 struct perf_event, active_list);
3984 /* if no active flexible event, pick the first event */
3986 event = rb_entry_safe(rb_first(&ctx->flexible_groups.tree),
3987 typeof(*event), group_node);
3991 * Unconditionally clear rotate_necessary; if ctx_flexible_sched_in()
3992 * finds there are unschedulable events, it will set it again.
3994 ctx->rotate_necessary = 0;
3999 static bool perf_rotate_context(struct perf_cpu_context *cpuctx)
4001 struct perf_event *cpu_event = NULL, *task_event = NULL;
4002 struct perf_event_context *task_ctx = NULL;
4003 int cpu_rotate, task_rotate;
4006 * Since we run this from IRQ context, nobody can install new
4007 * events, thus the event count values are stable.
4010 cpu_rotate = cpuctx->ctx.rotate_necessary;
4011 task_ctx = cpuctx->task_ctx;
4012 task_rotate = task_ctx ? task_ctx->rotate_necessary : 0;
4014 if (!(cpu_rotate || task_rotate))
4017 perf_ctx_lock(cpuctx, cpuctx->task_ctx);
4018 perf_pmu_disable(cpuctx->ctx.pmu);
4021 task_event = ctx_event_to_rotate(task_ctx);
4023 cpu_event = ctx_event_to_rotate(&cpuctx->ctx);
4026 * As per the order given at ctx_resched() first 'pop' task flexible
4027 * and then, if needed CPU flexible.
4029 if (task_event || (task_ctx && cpu_event))
4030 ctx_sched_out(task_ctx, cpuctx, EVENT_FLEXIBLE);
4032 cpu_ctx_sched_out(cpuctx, EVENT_FLEXIBLE);
4035 rotate_ctx(task_ctx, task_event);
4037 rotate_ctx(&cpuctx->ctx, cpu_event);
4039 perf_event_sched_in(cpuctx, task_ctx, current);
4041 perf_pmu_enable(cpuctx->ctx.pmu);
4042 perf_ctx_unlock(cpuctx, cpuctx->task_ctx);
4047 void perf_event_task_tick(void)
4049 struct list_head *head = this_cpu_ptr(&active_ctx_list);
4050 struct perf_event_context *ctx, *tmp;
4053 lockdep_assert_irqs_disabled();
4055 __this_cpu_inc(perf_throttled_seq);
4056 throttled = __this_cpu_xchg(perf_throttled_count, 0);
4057 tick_dep_clear_cpu(smp_processor_id(), TICK_DEP_BIT_PERF_EVENTS);
4059 list_for_each_entry_safe(ctx, tmp, head, active_ctx_list)
4060 perf_adjust_freq_unthr_context(ctx, throttled);
4063 static int event_enable_on_exec(struct perf_event *event,
4064 struct perf_event_context *ctx)
4066 if (!event->attr.enable_on_exec)
4069 event->attr.enable_on_exec = 0;
4070 if (event->state >= PERF_EVENT_STATE_INACTIVE)
4073 perf_event_set_state(event, PERF_EVENT_STATE_INACTIVE);
4079 * Enable all of a task's events that have been marked enable-on-exec.
4080 * This expects task == current.
4082 static void perf_event_enable_on_exec(int ctxn)
4084 struct perf_event_context *ctx, *clone_ctx = NULL;
4085 enum event_type_t event_type = 0;
4086 struct perf_cpu_context *cpuctx;
4087 struct perf_event *event;
4088 unsigned long flags;
4091 local_irq_save(flags);
4092 ctx = current->perf_event_ctxp[ctxn];
4093 if (!ctx || !ctx->nr_events)
4096 cpuctx = __get_cpu_context(ctx);
4097 perf_ctx_lock(cpuctx, ctx);
4098 ctx_sched_out(ctx, cpuctx, EVENT_TIME);
4099 list_for_each_entry(event, &ctx->event_list, event_entry) {
4100 enabled |= event_enable_on_exec(event, ctx);
4101 event_type |= get_event_type(event);
4105 * Unclone and reschedule this context if we enabled any event.
4108 clone_ctx = unclone_ctx(ctx);
4109 ctx_resched(cpuctx, ctx, event_type);
4111 ctx_sched_in(ctx, cpuctx, EVENT_TIME, current);
4113 perf_ctx_unlock(cpuctx, ctx);
4116 local_irq_restore(flags);
4122 struct perf_read_data {
4123 struct perf_event *event;
4128 static int __perf_event_read_cpu(struct perf_event *event, int event_cpu)
4130 u16 local_pkg, event_pkg;
4132 if (event->group_caps & PERF_EV_CAP_READ_ACTIVE_PKG) {
4133 int local_cpu = smp_processor_id();
4135 event_pkg = topology_physical_package_id(event_cpu);
4136 local_pkg = topology_physical_package_id(local_cpu);
4138 if (event_pkg == local_pkg)
4146 * Cross CPU call to read the hardware event
4148 static void __perf_event_read(void *info)
4150 struct perf_read_data *data = info;
4151 struct perf_event *sub, *event = data->event;
4152 struct perf_event_context *ctx = event->ctx;
4153 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
4154 struct pmu *pmu = event->pmu;
4157 * If this is a task context, we need to check whether it is
4158 * the current task context of this cpu. If not it has been
4159 * scheduled out before the smp call arrived. In that case
4160 * event->count would have been updated to a recent sample
4161 * when the event was scheduled out.
4163 if (ctx->task && cpuctx->task_ctx != ctx)
4166 raw_spin_lock(&ctx->lock);
4167 if (ctx->is_active & EVENT_TIME) {
4168 update_context_time(ctx);
4169 update_cgrp_time_from_event(event);
4172 perf_event_update_time(event);
4174 perf_event_update_sibling_time(event);
4176 if (event->state != PERF_EVENT_STATE_ACTIVE)
4185 pmu->start_txn(pmu, PERF_PMU_TXN_READ);
4189 for_each_sibling_event(sub, event) {
4190 if (sub->state == PERF_EVENT_STATE_ACTIVE) {
4192 * Use sibling's PMU rather than @event's since
4193 * sibling could be on different (eg: software) PMU.
4195 sub->pmu->read(sub);
4199 data->ret = pmu->commit_txn(pmu);
4202 raw_spin_unlock(&ctx->lock);
4205 static inline u64 perf_event_count(struct perf_event *event)
4207 return local64_read(&event->count) + atomic64_read(&event->child_count);
4211 * NMI-safe method to read a local event, that is an event that
4213 * - either for the current task, or for this CPU
4214 * - does not have inherit set, for inherited task events
4215 * will not be local and we cannot read them atomically
4216 * - must not have a pmu::count method
4218 int perf_event_read_local(struct perf_event *event, u64 *value,
4219 u64 *enabled, u64 *running)
4221 unsigned long flags;
4225 * Disabling interrupts avoids all counter scheduling (context
4226 * switches, timer based rotation and IPIs).
4228 local_irq_save(flags);
4231 * It must not be an event with inherit set, we cannot read
4232 * all child counters from atomic context.
4234 if (event->attr.inherit) {
4239 /* If this is a per-task event, it must be for current */
4240 if ((event->attach_state & PERF_ATTACH_TASK) &&
4241 event->hw.target != current) {
4246 /* If this is a per-CPU event, it must be for this CPU */
4247 if (!(event->attach_state & PERF_ATTACH_TASK) &&
4248 event->cpu != smp_processor_id()) {
4253 /* If this is a pinned event it must be running on this CPU */
4254 if (event->attr.pinned && event->oncpu != smp_processor_id()) {
4260 * If the event is currently on this CPU, its either a per-task event,
4261 * or local to this CPU. Furthermore it means its ACTIVE (otherwise
4264 if (event->oncpu == smp_processor_id())
4265 event->pmu->read(event);
4267 *value = local64_read(&event->count);
4268 if (enabled || running) {
4269 u64 now = event->shadow_ctx_time + perf_clock();
4270 u64 __enabled, __running;
4272 __perf_update_times(event, now, &__enabled, &__running);
4274 *enabled = __enabled;
4276 *running = __running;
4279 local_irq_restore(flags);
4284 static int perf_event_read(struct perf_event *event, bool group)
4286 enum perf_event_state state = READ_ONCE(event->state);
4287 int event_cpu, ret = 0;
4290 * If event is enabled and currently active on a CPU, update the
4291 * value in the event structure:
4294 if (state == PERF_EVENT_STATE_ACTIVE) {
4295 struct perf_read_data data;
4298 * Orders the ->state and ->oncpu loads such that if we see
4299 * ACTIVE we must also see the right ->oncpu.
4301 * Matches the smp_wmb() from event_sched_in().
4305 event_cpu = READ_ONCE(event->oncpu);
4306 if ((unsigned)event_cpu >= nr_cpu_ids)
4309 data = (struct perf_read_data){
4316 event_cpu = __perf_event_read_cpu(event, event_cpu);
4319 * Purposely ignore the smp_call_function_single() return
4322 * If event_cpu isn't a valid CPU it means the event got
4323 * scheduled out and that will have updated the event count.
4325 * Therefore, either way, we'll have an up-to-date event count
4328 (void)smp_call_function_single(event_cpu, __perf_event_read, &data, 1);
4332 } else if (state == PERF_EVENT_STATE_INACTIVE) {
4333 struct perf_event_context *ctx = event->ctx;
4334 unsigned long flags;
4336 raw_spin_lock_irqsave(&ctx->lock, flags);
4337 state = event->state;
4338 if (state != PERF_EVENT_STATE_INACTIVE) {
4339 raw_spin_unlock_irqrestore(&ctx->lock, flags);
4344 * May read while context is not active (e.g., thread is
4345 * blocked), in that case we cannot update context time
4347 if (ctx->is_active & EVENT_TIME) {
4348 update_context_time(ctx);
4349 update_cgrp_time_from_event(event);
4352 perf_event_update_time(event);
4354 perf_event_update_sibling_time(event);
4355 raw_spin_unlock_irqrestore(&ctx->lock, flags);
4362 * Initialize the perf_event context in a task_struct:
4364 static void __perf_event_init_context(struct perf_event_context *ctx)
4366 raw_spin_lock_init(&ctx->lock);
4367 mutex_init(&ctx->mutex);
4368 INIT_LIST_HEAD(&ctx->active_ctx_list);
4369 perf_event_groups_init(&ctx->pinned_groups);
4370 perf_event_groups_init(&ctx->flexible_groups);
4371 INIT_LIST_HEAD(&ctx->event_list);
4372 INIT_LIST_HEAD(&ctx->pinned_active);
4373 INIT_LIST_HEAD(&ctx->flexible_active);
4374 refcount_set(&ctx->refcount, 1);
4377 static struct perf_event_context *
4378 alloc_perf_context(struct pmu *pmu, struct task_struct *task)
4380 struct perf_event_context *ctx;
4382 ctx = kzalloc(sizeof(struct perf_event_context), GFP_KERNEL);
4386 __perf_event_init_context(ctx);
4388 ctx->task = get_task_struct(task);
4394 static struct task_struct *
4395 find_lively_task_by_vpid(pid_t vpid)
4397 struct task_struct *task;
4403 task = find_task_by_vpid(vpid);
4405 get_task_struct(task);
4409 return ERR_PTR(-ESRCH);
4415 * Returns a matching context with refcount and pincount.
4417 static struct perf_event_context *
4418 find_get_context(struct pmu *pmu, struct task_struct *task,
4419 struct perf_event *event)
4421 struct perf_event_context *ctx, *clone_ctx = NULL;
4422 struct perf_cpu_context *cpuctx;
4423 void *task_ctx_data = NULL;
4424 unsigned long flags;
4426 int cpu = event->cpu;
4429 /* Must be root to operate on a CPU event: */
4430 err = perf_allow_cpu(&event->attr);
4432 return ERR_PTR(err);
4434 cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
4443 ctxn = pmu->task_ctx_nr;
4447 if (event->attach_state & PERF_ATTACH_TASK_DATA) {
4448 task_ctx_data = kzalloc(pmu->task_ctx_size, GFP_KERNEL);
4449 if (!task_ctx_data) {
4456 ctx = perf_lock_task_context(task, ctxn, &flags);
4458 clone_ctx = unclone_ctx(ctx);
4461 if (task_ctx_data && !ctx->task_ctx_data) {
4462 ctx->task_ctx_data = task_ctx_data;
4463 task_ctx_data = NULL;
4465 raw_spin_unlock_irqrestore(&ctx->lock, flags);
4470 ctx = alloc_perf_context(pmu, task);
4475 if (task_ctx_data) {
4476 ctx->task_ctx_data = task_ctx_data;
4477 task_ctx_data = NULL;
4481 mutex_lock(&task->perf_event_mutex);
4483 * If it has already passed perf_event_exit_task().
4484 * we must see PF_EXITING, it takes this mutex too.
4486 if (task->flags & PF_EXITING)
4488 else if (task->perf_event_ctxp[ctxn])
4493 rcu_assign_pointer(task->perf_event_ctxp[ctxn], ctx);
4495 mutex_unlock(&task->perf_event_mutex);
4497 if (unlikely(err)) {
4506 kfree(task_ctx_data);
4510 kfree(task_ctx_data);
4511 return ERR_PTR(err);
4514 static void perf_event_free_filter(struct perf_event *event);
4515 static void perf_event_free_bpf_prog(struct perf_event *event);
4517 static void free_event_rcu(struct rcu_head *head)
4519 struct perf_event *event;
4521 event = container_of(head, struct perf_event, rcu_head);
4523 put_pid_ns(event->ns);
4524 perf_event_free_filter(event);
4528 static void ring_buffer_attach(struct perf_event *event,
4529 struct perf_buffer *rb);
4531 static void detach_sb_event(struct perf_event *event)
4533 struct pmu_event_list *pel = per_cpu_ptr(&pmu_sb_events, event->cpu);
4535 raw_spin_lock(&pel->lock);
4536 list_del_rcu(&event->sb_list);
4537 raw_spin_unlock(&pel->lock);
4540 static bool is_sb_event(struct perf_event *event)
4542 struct perf_event_attr *attr = &event->attr;
4547 if (event->attach_state & PERF_ATTACH_TASK)
4550 if (attr->mmap || attr->mmap_data || attr->mmap2 ||
4551 attr->comm || attr->comm_exec ||
4552 attr->task || attr->ksymbol ||
4553 attr->context_switch ||
4559 static void unaccount_pmu_sb_event(struct perf_event *event)
4561 if (is_sb_event(event))
4562 detach_sb_event(event);
4565 static void unaccount_event_cpu(struct perf_event *event, int cpu)
4570 if (is_cgroup_event(event))
4571 atomic_dec(&per_cpu(perf_cgroup_events, cpu));
4574 #ifdef CONFIG_NO_HZ_FULL
4575 static DEFINE_SPINLOCK(nr_freq_lock);
4578 static void unaccount_freq_event_nohz(void)
4580 #ifdef CONFIG_NO_HZ_FULL
4581 spin_lock(&nr_freq_lock);
4582 if (atomic_dec_and_test(&nr_freq_events))
4583 tick_nohz_dep_clear(TICK_DEP_BIT_PERF_EVENTS);
4584 spin_unlock(&nr_freq_lock);
4588 static void unaccount_freq_event(void)
4590 if (tick_nohz_full_enabled())
4591 unaccount_freq_event_nohz();
4593 atomic_dec(&nr_freq_events);
4596 static void unaccount_event(struct perf_event *event)
4603 if (event->attach_state & PERF_ATTACH_TASK)
4605 if (event->attr.mmap || event->attr.mmap_data)
4606 atomic_dec(&nr_mmap_events);
4607 if (event->attr.comm)
4608 atomic_dec(&nr_comm_events);
4609 if (event->attr.namespaces)
4610 atomic_dec(&nr_namespaces_events);
4611 if (event->attr.task)
4612 atomic_dec(&nr_task_events);
4613 if (event->attr.freq)
4614 unaccount_freq_event();
4615 if (event->attr.context_switch) {
4617 atomic_dec(&nr_switch_events);
4619 if (is_cgroup_event(event))
4621 if (has_branch_stack(event))
4623 if (event->attr.ksymbol)
4624 atomic_dec(&nr_ksymbol_events);
4625 if (event->attr.bpf_event)
4626 atomic_dec(&nr_bpf_events);
4629 if (!atomic_add_unless(&perf_sched_count, -1, 1))
4630 schedule_delayed_work(&perf_sched_work, HZ);
4633 unaccount_event_cpu(event, event->cpu);
4635 unaccount_pmu_sb_event(event);
4638 static void perf_sched_delayed(struct work_struct *work)
4640 mutex_lock(&perf_sched_mutex);
4641 if (atomic_dec_and_test(&perf_sched_count))
4642 static_branch_disable(&perf_sched_events);
4643 mutex_unlock(&perf_sched_mutex);
4647 * The following implement mutual exclusion of events on "exclusive" pmus
4648 * (PERF_PMU_CAP_EXCLUSIVE). Such pmus can only have one event scheduled
4649 * at a time, so we disallow creating events that might conflict, namely:
4651 * 1) cpu-wide events in the presence of per-task events,
4652 * 2) per-task events in the presence of cpu-wide events,
4653 * 3) two matching events on the same context.
4655 * The former two cases are handled in the allocation path (perf_event_alloc(),
4656 * _free_event()), the latter -- before the first perf_install_in_context().
4658 static int exclusive_event_init(struct perf_event *event)
4660 struct pmu *pmu = event->pmu;
4662 if (!is_exclusive_pmu(pmu))
4666 * Prevent co-existence of per-task and cpu-wide events on the
4667 * same exclusive pmu.
4669 * Negative pmu::exclusive_cnt means there are cpu-wide
4670 * events on this "exclusive" pmu, positive means there are
4673 * Since this is called in perf_event_alloc() path, event::ctx
4674 * doesn't exist yet; it is, however, safe to use PERF_ATTACH_TASK
4675 * to mean "per-task event", because unlike other attach states it
4676 * never gets cleared.
4678 if (event->attach_state & PERF_ATTACH_TASK) {
4679 if (!atomic_inc_unless_negative(&pmu->exclusive_cnt))
4682 if (!atomic_dec_unless_positive(&pmu->exclusive_cnt))
4689 static void exclusive_event_destroy(struct perf_event *event)
4691 struct pmu *pmu = event->pmu;
4693 if (!is_exclusive_pmu(pmu))
4696 /* see comment in exclusive_event_init() */
4697 if (event->attach_state & PERF_ATTACH_TASK)
4698 atomic_dec(&pmu->exclusive_cnt);
4700 atomic_inc(&pmu->exclusive_cnt);
4703 static bool exclusive_event_match(struct perf_event *e1, struct perf_event *e2)
4705 if ((e1->pmu == e2->pmu) &&
4706 (e1->cpu == e2->cpu ||
4713 static bool exclusive_event_installable(struct perf_event *event,
4714 struct perf_event_context *ctx)
4716 struct perf_event *iter_event;
4717 struct pmu *pmu = event->pmu;
4719 lockdep_assert_held(&ctx->mutex);
4721 if (!is_exclusive_pmu(pmu))
4724 list_for_each_entry(iter_event, &ctx->event_list, event_entry) {
4725 if (exclusive_event_match(iter_event, event))
4732 static void perf_addr_filters_splice(struct perf_event *event,
4733 struct list_head *head);
4735 static void _free_event(struct perf_event *event)
4737 irq_work_sync(&event->pending);
4739 unaccount_event(event);
4741 security_perf_event_free(event);
4745 * Can happen when we close an event with re-directed output.
4747 * Since we have a 0 refcount, perf_mmap_close() will skip
4748 * over us; possibly making our ring_buffer_put() the last.
4750 mutex_lock(&event->mmap_mutex);
4751 ring_buffer_attach(event, NULL);
4752 mutex_unlock(&event->mmap_mutex);
4755 if (is_cgroup_event(event))
4756 perf_detach_cgroup(event);
4758 if (!event->parent) {
4759 if (event->attr.sample_type & PERF_SAMPLE_CALLCHAIN)
4760 put_callchain_buffers();
4763 perf_event_free_bpf_prog(event);
4764 perf_addr_filters_splice(event, NULL);
4765 kfree(event->addr_filter_ranges);
4768 event->destroy(event);
4771 * Must be after ->destroy(), due to uprobe_perf_close() using
4774 if (event->hw.target)
4775 put_task_struct(event->hw.target);
4778 * perf_event_free_task() relies on put_ctx() being 'last', in particular
4779 * all task references must be cleaned up.
4782 put_ctx(event->ctx);
4784 exclusive_event_destroy(event);
4785 module_put(event->pmu->module);
4787 call_rcu(&event->rcu_head, free_event_rcu);
4791 * Used to free events which have a known refcount of 1, such as in error paths
4792 * where the event isn't exposed yet and inherited events.
4794 static void free_event(struct perf_event *event)
4796 if (WARN(atomic_long_cmpxchg(&event->refcount, 1, 0) != 1,
4797 "unexpected event refcount: %ld; ptr=%p\n",
4798 atomic_long_read(&event->refcount), event)) {
4799 /* leak to avoid use-after-free */
4807 * Remove user event from the owner task.
4809 static void perf_remove_from_owner(struct perf_event *event)
4811 struct task_struct *owner;
4815 * Matches the smp_store_release() in perf_event_exit_task(). If we
4816 * observe !owner it means the list deletion is complete and we can
4817 * indeed free this event, otherwise we need to serialize on
4818 * owner->perf_event_mutex.
4820 owner = READ_ONCE(event->owner);
4823 * Since delayed_put_task_struct() also drops the last
4824 * task reference we can safely take a new reference
4825 * while holding the rcu_read_lock().
4827 get_task_struct(owner);
4833 * If we're here through perf_event_exit_task() we're already
4834 * holding ctx->mutex which would be an inversion wrt. the
4835 * normal lock order.
4837 * However we can safely take this lock because its the child
4840 mutex_lock_nested(&owner->perf_event_mutex, SINGLE_DEPTH_NESTING);
4843 * We have to re-check the event->owner field, if it is cleared
4844 * we raced with perf_event_exit_task(), acquiring the mutex
4845 * ensured they're done, and we can proceed with freeing the
4849 list_del_init(&event->owner_entry);
4850 smp_store_release(&event->owner, NULL);
4852 mutex_unlock(&owner->perf_event_mutex);
4853 put_task_struct(owner);
4857 static void put_event(struct perf_event *event)
4859 if (!atomic_long_dec_and_test(&event->refcount))
4866 * Kill an event dead; while event:refcount will preserve the event
4867 * object, it will not preserve its functionality. Once the last 'user'
4868 * gives up the object, we'll destroy the thing.
4870 int perf_event_release_kernel(struct perf_event *event)
4872 struct perf_event_context *ctx = event->ctx;
4873 struct perf_event *child, *tmp;
4874 LIST_HEAD(free_list);
4877 * If we got here through err_file: fput(event_file); we will not have
4878 * attached to a context yet.
4881 WARN_ON_ONCE(event->attach_state &
4882 (PERF_ATTACH_CONTEXT|PERF_ATTACH_GROUP));
4886 if (!is_kernel_event(event))
4887 perf_remove_from_owner(event);
4889 ctx = perf_event_ctx_lock(event);
4890 WARN_ON_ONCE(ctx->parent_ctx);
4891 perf_remove_from_context(event, DETACH_GROUP);
4893 raw_spin_lock_irq(&ctx->lock);
4895 * Mark this event as STATE_DEAD, there is no external reference to it
4898 * Anybody acquiring event->child_mutex after the below loop _must_
4899 * also see this, most importantly inherit_event() which will avoid
4900 * placing more children on the list.
4902 * Thus this guarantees that we will in fact observe and kill _ALL_
4905 event->state = PERF_EVENT_STATE_DEAD;
4906 raw_spin_unlock_irq(&ctx->lock);
4908 perf_event_ctx_unlock(event, ctx);
4911 mutex_lock(&event->child_mutex);
4912 list_for_each_entry(child, &event->child_list, child_list) {
4915 * Cannot change, child events are not migrated, see the
4916 * comment with perf_event_ctx_lock_nested().
4918 ctx = READ_ONCE(child->ctx);
4920 * Since child_mutex nests inside ctx::mutex, we must jump
4921 * through hoops. We start by grabbing a reference on the ctx.
4923 * Since the event cannot get freed while we hold the
4924 * child_mutex, the context must also exist and have a !0
4930 * Now that we have a ctx ref, we can drop child_mutex, and
4931 * acquire ctx::mutex without fear of it going away. Then we
4932 * can re-acquire child_mutex.
4934 mutex_unlock(&event->child_mutex);
4935 mutex_lock(&ctx->mutex);
4936 mutex_lock(&event->child_mutex);
4939 * Now that we hold ctx::mutex and child_mutex, revalidate our
4940 * state, if child is still the first entry, it didn't get freed
4941 * and we can continue doing so.
4943 tmp = list_first_entry_or_null(&event->child_list,
4944 struct perf_event, child_list);
4946 perf_remove_from_context(child, DETACH_GROUP);
4947 list_move(&child->child_list, &free_list);
4949 * This matches the refcount bump in inherit_event();
4950 * this can't be the last reference.
4955 mutex_unlock(&event->child_mutex);
4956 mutex_unlock(&ctx->mutex);
4960 mutex_unlock(&event->child_mutex);
4962 list_for_each_entry_safe(child, tmp, &free_list, child_list) {
4963 void *var = &child->ctx->refcount;
4965 list_del(&child->child_list);
4969 * Wake any perf_event_free_task() waiting for this event to be
4972 smp_mb(); /* pairs with wait_var_event() */
4977 put_event(event); /* Must be the 'last' reference */
4980 EXPORT_SYMBOL_GPL(perf_event_release_kernel);
4983 * Called when the last reference to the file is gone.
4985 static int perf_release(struct inode *inode, struct file *file)
4987 perf_event_release_kernel(file->private_data);
4991 static u64 __perf_event_read_value(struct perf_event *event, u64 *enabled, u64 *running)
4993 struct perf_event *child;
4999 mutex_lock(&event->child_mutex);
5001 (void)perf_event_read(event, false);
5002 total += perf_event_count(event);
5004 *enabled += event->total_time_enabled +
5005 atomic64_read(&event->child_total_time_enabled);
5006 *running += event->total_time_running +
5007 atomic64_read(&event->child_total_time_running);
5009 list_for_each_entry(child, &event->child_list, child_list) {
5010 (void)perf_event_read(child, false);
5011 total += perf_event_count(child);
5012 *enabled += child->total_time_enabled;
5013 *running += child->total_time_running;
5015 mutex_unlock(&event->child_mutex);
5020 u64 perf_event_read_value(struct perf_event *event, u64 *enabled, u64 *running)
5022 struct perf_event_context *ctx;
5025 ctx = perf_event_ctx_lock(event);
5026 count = __perf_event_read_value(event, enabled, running);
5027 perf_event_ctx_unlock(event, ctx);
5031 EXPORT_SYMBOL_GPL(perf_event_read_value);
5033 static int __perf_read_group_add(struct perf_event *leader,
5034 u64 read_format, u64 *values)
5036 struct perf_event_context *ctx = leader->ctx;
5037 struct perf_event *sub;
5038 unsigned long flags;
5039 int n = 1; /* skip @nr */
5042 ret = perf_event_read(leader, true);
5046 raw_spin_lock_irqsave(&ctx->lock, flags);
5049 * Since we co-schedule groups, {enabled,running} times of siblings
5050 * will be identical to those of the leader, so we only publish one
5053 if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED) {
5054 values[n++] += leader->total_time_enabled +
5055 atomic64_read(&leader->child_total_time_enabled);
5058 if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING) {
5059 values[n++] += leader->total_time_running +
5060 atomic64_read(&leader->child_total_time_running);
5064 * Write {count,id} tuples for every sibling.
5066 values[n++] += perf_event_count(leader);
5067 if (read_format & PERF_FORMAT_ID)
5068 values[n++] = primary_event_id(leader);
5070 for_each_sibling_event(sub, leader) {
5071 values[n++] += perf_event_count(sub);
5072 if (read_format & PERF_FORMAT_ID)
5073 values[n++] = primary_event_id(sub);
5076 raw_spin_unlock_irqrestore(&ctx->lock, flags);
5080 static int perf_read_group(struct perf_event *event,
5081 u64 read_format, char __user *buf)
5083 struct perf_event *leader = event->group_leader, *child;
5084 struct perf_event_context *ctx = leader->ctx;
5088 lockdep_assert_held(&ctx->mutex);
5090 values = kzalloc(event->read_size, GFP_KERNEL);
5094 values[0] = 1 + leader->nr_siblings;
5097 * By locking the child_mutex of the leader we effectively
5098 * lock the child list of all siblings.. XXX explain how.
5100 mutex_lock(&leader->child_mutex);
5102 ret = __perf_read_group_add(leader, read_format, values);
5106 list_for_each_entry(child, &leader->child_list, child_list) {
5107 ret = __perf_read_group_add(child, read_format, values);
5112 mutex_unlock(&leader->child_mutex);
5114 ret = event->read_size;
5115 if (copy_to_user(buf, values, event->read_size))
5120 mutex_unlock(&leader->child_mutex);
5126 static int perf_read_one(struct perf_event *event,
5127 u64 read_format, char __user *buf)
5129 u64 enabled, running;
5133 values[n++] = __perf_event_read_value(event, &enabled, &running);
5134 if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED)
5135 values[n++] = enabled;
5136 if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING)
5137 values[n++] = running;
5138 if (read_format & PERF_FORMAT_ID)
5139 values[n++] = primary_event_id(event);
5141 if (copy_to_user(buf, values, n * sizeof(u64)))
5144 return n * sizeof(u64);
5147 static bool is_event_hup(struct perf_event *event)
5151 if (event->state > PERF_EVENT_STATE_EXIT)
5154 mutex_lock(&event->child_mutex);
5155 no_children = list_empty(&event->child_list);
5156 mutex_unlock(&event->child_mutex);
5161 * Read the performance event - simple non blocking version for now
5164 __perf_read(struct perf_event *event, char __user *buf, size_t count)
5166 u64 read_format = event->attr.read_format;
5170 * Return end-of-file for a read on an event that is in
5171 * error state (i.e. because it was pinned but it couldn't be
5172 * scheduled on to the CPU at some point).
5174 if (event->state == PERF_EVENT_STATE_ERROR)
5177 if (count < event->read_size)
5180 WARN_ON_ONCE(event->ctx->parent_ctx);
5181 if (read_format & PERF_FORMAT_GROUP)
5182 ret = perf_read_group(event, read_format, buf);
5184 ret = perf_read_one(event, read_format, buf);
5190 perf_read(struct file *file, char __user *buf, size_t count, loff_t *ppos)
5192 struct perf_event *event = file->private_data;
5193 struct perf_event_context *ctx;
5196 ret = security_perf_event_read(event);
5200 ctx = perf_event_ctx_lock(event);
5201 ret = __perf_read(event, buf, count);
5202 perf_event_ctx_unlock(event, ctx);
5207 static __poll_t perf_poll(struct file *file, poll_table *wait)
5209 struct perf_event *event = file->private_data;
5210 struct perf_buffer *rb;
5211 __poll_t events = EPOLLHUP;
5213 poll_wait(file, &event->waitq, wait);
5215 if (is_event_hup(event))
5219 * Pin the event->rb by taking event->mmap_mutex; otherwise
5220 * perf_event_set_output() can swizzle our rb and make us miss wakeups.
5222 mutex_lock(&event->mmap_mutex);
5225 events = atomic_xchg(&rb->poll, 0);
5226 mutex_unlock(&event->mmap_mutex);
5230 static void _perf_event_reset(struct perf_event *event)
5232 (void)perf_event_read(event, false);
5233 local64_set(&event->count, 0);
5234 perf_event_update_userpage(event);
5237 /* Assume it's not an event with inherit set. */
5238 u64 perf_event_pause(struct perf_event *event, bool reset)
5240 struct perf_event_context *ctx;
5243 ctx = perf_event_ctx_lock(event);
5244 WARN_ON_ONCE(event->attr.inherit);
5245 _perf_event_disable(event);
5246 count = local64_read(&event->count);
5248 local64_set(&event->count, 0);
5249 perf_event_ctx_unlock(event, ctx);
5253 EXPORT_SYMBOL_GPL(perf_event_pause);
5256 * Holding the top-level event's child_mutex means that any
5257 * descendant process that has inherited this event will block
5258 * in perf_event_exit_event() if it goes to exit, thus satisfying the
5259 * task existence requirements of perf_event_enable/disable.
5261 static void perf_event_for_each_child(struct perf_event *event,
5262 void (*func)(struct perf_event *))
5264 struct perf_event *child;
5266 WARN_ON_ONCE(event->ctx->parent_ctx);
5268 mutex_lock(&event->child_mutex);
5270 list_for_each_entry(child, &event->child_list, child_list)
5272 mutex_unlock(&event->child_mutex);
5275 static void perf_event_for_each(struct perf_event *event,
5276 void (*func)(struct perf_event *))
5278 struct perf_event_context *ctx = event->ctx;
5279 struct perf_event *sibling;
5281 lockdep_assert_held(&ctx->mutex);
5283 event = event->group_leader;
5285 perf_event_for_each_child(event, func);
5286 for_each_sibling_event(sibling, event)
5287 perf_event_for_each_child(sibling, func);
5290 static void __perf_event_period(struct perf_event *event,
5291 struct perf_cpu_context *cpuctx,
5292 struct perf_event_context *ctx,
5295 u64 value = *((u64 *)info);
5298 if (event->attr.freq) {
5299 event->attr.sample_freq = value;
5301 event->attr.sample_period = value;
5302 event->hw.sample_period = value;
5305 active = (event->state == PERF_EVENT_STATE_ACTIVE);
5307 perf_pmu_disable(ctx->pmu);
5309 * We could be throttled; unthrottle now to avoid the tick
5310 * trying to unthrottle while we already re-started the event.
5312 if (event->hw.interrupts == MAX_INTERRUPTS) {
5313 event->hw.interrupts = 0;
5314 perf_log_throttle(event, 1);
5316 event->pmu->stop(event, PERF_EF_UPDATE);
5319 local64_set(&event->hw.period_left, 0);
5322 event->pmu->start(event, PERF_EF_RELOAD);
5323 perf_pmu_enable(ctx->pmu);
5327 static int perf_event_check_period(struct perf_event *event, u64 value)
5329 return event->pmu->check_period(event, value);
5332 static int _perf_event_period(struct perf_event *event, u64 value)
5334 if (!is_sampling_event(event))
5340 if (event->attr.freq && value > sysctl_perf_event_sample_rate)
5343 if (perf_event_check_period(event, value))
5346 if (!event->attr.freq && (value & (1ULL << 63)))
5349 event_function_call(event, __perf_event_period, &value);
5354 int perf_event_period(struct perf_event *event, u64 value)
5356 struct perf_event_context *ctx;
5359 ctx = perf_event_ctx_lock(event);
5360 ret = _perf_event_period(event, value);
5361 perf_event_ctx_unlock(event, ctx);
5365 EXPORT_SYMBOL_GPL(perf_event_period);
5367 static const struct file_operations perf_fops;
5369 static inline int perf_fget_light(int fd, struct fd *p)
5371 struct fd f = fdget(fd);
5375 if (f.file->f_op != &perf_fops) {
5383 static int perf_event_set_output(struct perf_event *event,
5384 struct perf_event *output_event);
5385 static int perf_event_set_filter(struct perf_event *event, void __user *arg);
5386 static int perf_event_set_bpf_prog(struct perf_event *event, u32 prog_fd);
5387 static int perf_copy_attr(struct perf_event_attr __user *uattr,
5388 struct perf_event_attr *attr);
5390 static long _perf_ioctl(struct perf_event *event, unsigned int cmd, unsigned long arg)
5392 void (*func)(struct perf_event *);
5396 case PERF_EVENT_IOC_ENABLE:
5397 func = _perf_event_enable;
5399 case PERF_EVENT_IOC_DISABLE:
5400 func = _perf_event_disable;
5402 case PERF_EVENT_IOC_RESET:
5403 func = _perf_event_reset;
5406 case PERF_EVENT_IOC_REFRESH:
5407 return _perf_event_refresh(event, arg);
5409 case PERF_EVENT_IOC_PERIOD:
5413 if (copy_from_user(&value, (u64 __user *)arg, sizeof(value)))
5416 return _perf_event_period(event, value);
5418 case PERF_EVENT_IOC_ID:
5420 u64 id = primary_event_id(event);
5422 if (copy_to_user((void __user *)arg, &id, sizeof(id)))
5427 case PERF_EVENT_IOC_SET_OUTPUT:
5431 struct perf_event *output_event;
5433 ret = perf_fget_light(arg, &output);
5436 output_event = output.file->private_data;
5437 ret = perf_event_set_output(event, output_event);
5440 ret = perf_event_set_output(event, NULL);
5445 case PERF_EVENT_IOC_SET_FILTER:
5446 return perf_event_set_filter(event, (void __user *)arg);
5448 case PERF_EVENT_IOC_SET_BPF:
5449 return perf_event_set_bpf_prog(event, arg);
5451 case PERF_EVENT_IOC_PAUSE_OUTPUT: {
5452 struct perf_buffer *rb;
5455 rb = rcu_dereference(event->rb);
5456 if (!rb || !rb->nr_pages) {
5460 rb_toggle_paused(rb, !!arg);
5465 case PERF_EVENT_IOC_QUERY_BPF:
5466 return perf_event_query_prog_array(event, (void __user *)arg);
5468 case PERF_EVENT_IOC_MODIFY_ATTRIBUTES: {
5469 struct perf_event_attr new_attr;
5470 int err = perf_copy_attr((struct perf_event_attr __user *)arg,
5476 return perf_event_modify_attr(event, &new_attr);
5482 if (flags & PERF_IOC_FLAG_GROUP)
5483 perf_event_for_each(event, func);
5485 perf_event_for_each_child(event, func);
5490 static long perf_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
5492 struct perf_event *event = file->private_data;
5493 struct perf_event_context *ctx;
5496 /* Treat ioctl like writes as it is likely a mutating operation. */
5497 ret = security_perf_event_write(event);
5501 ctx = perf_event_ctx_lock(event);
5502 ret = _perf_ioctl(event, cmd, arg);
5503 perf_event_ctx_unlock(event, ctx);
5508 #ifdef CONFIG_COMPAT
5509 static long perf_compat_ioctl(struct file *file, unsigned int cmd,
5512 switch (_IOC_NR(cmd)) {
5513 case _IOC_NR(PERF_EVENT_IOC_SET_FILTER):
5514 case _IOC_NR(PERF_EVENT_IOC_ID):
5515 case _IOC_NR(PERF_EVENT_IOC_QUERY_BPF):
5516 case _IOC_NR(PERF_EVENT_IOC_MODIFY_ATTRIBUTES):
5517 /* Fix up pointer size (usually 4 -> 8 in 32-on-64-bit case */
5518 if (_IOC_SIZE(cmd) == sizeof(compat_uptr_t)) {
5519 cmd &= ~IOCSIZE_MASK;
5520 cmd |= sizeof(void *) << IOCSIZE_SHIFT;
5524 return perf_ioctl(file, cmd, arg);
5527 # define perf_compat_ioctl NULL
5530 int perf_event_task_enable(void)
5532 struct perf_event_context *ctx;
5533 struct perf_event *event;
5535 mutex_lock(¤t->perf_event_mutex);
5536 list_for_each_entry(event, ¤t->perf_event_list, owner_entry) {
5537 ctx = perf_event_ctx_lock(event);
5538 perf_event_for_each_child(event, _perf_event_enable);
5539 perf_event_ctx_unlock(event, ctx);
5541 mutex_unlock(¤t->perf_event_mutex);
5546 int perf_event_task_disable(void)
5548 struct perf_event_context *ctx;
5549 struct perf_event *event;
5551 mutex_lock(¤t->perf_event_mutex);
5552 list_for_each_entry(event, ¤t->perf_event_list, owner_entry) {
5553 ctx = perf_event_ctx_lock(event);
5554 perf_event_for_each_child(event, _perf_event_disable);
5555 perf_event_ctx_unlock(event, ctx);
5557 mutex_unlock(¤t->perf_event_mutex);
5562 static int perf_event_index(struct perf_event *event)
5564 if (event->hw.state & PERF_HES_STOPPED)
5567 if (event->state != PERF_EVENT_STATE_ACTIVE)
5570 return event->pmu->event_idx(event);
5573 static void calc_timer_values(struct perf_event *event,
5580 *now = perf_clock();
5581 ctx_time = event->shadow_ctx_time + *now;
5582 __perf_update_times(event, ctx_time, enabled, running);
5585 static void perf_event_init_userpage(struct perf_event *event)
5587 struct perf_event_mmap_page *userpg;
5588 struct perf_buffer *rb;
5591 rb = rcu_dereference(event->rb);
5595 userpg = rb->user_page;
5597 /* Allow new userspace to detect that bit 0 is deprecated */
5598 userpg->cap_bit0_is_deprecated = 1;
5599 userpg->size = offsetof(struct perf_event_mmap_page, __reserved);
5600 userpg->data_offset = PAGE_SIZE;
5601 userpg->data_size = perf_data_size(rb);
5607 void __weak arch_perf_update_userpage(
5608 struct perf_event *event, struct perf_event_mmap_page *userpg, u64 now)
5613 * Callers need to ensure there can be no nesting of this function, otherwise
5614 * the seqlock logic goes bad. We can not serialize this because the arch
5615 * code calls this from NMI context.
5617 void perf_event_update_userpage(struct perf_event *event)
5619 struct perf_event_mmap_page *userpg;
5620 struct perf_buffer *rb;
5621 u64 enabled, running, now;
5624 rb = rcu_dereference(event->rb);
5629 * compute total_time_enabled, total_time_running
5630 * based on snapshot values taken when the event
5631 * was last scheduled in.
5633 * we cannot simply called update_context_time()
5634 * because of locking issue as we can be called in
5637 calc_timer_values(event, &now, &enabled, &running);
5639 userpg = rb->user_page;
5641 * Disable preemption to guarantee consistent time stamps are stored to
5647 userpg->index = perf_event_index(event);
5648 userpg->offset = perf_event_count(event);
5650 userpg->offset -= local64_read(&event->hw.prev_count);
5652 userpg->time_enabled = enabled +
5653 atomic64_read(&event->child_total_time_enabled);
5655 userpg->time_running = running +
5656 atomic64_read(&event->child_total_time_running);
5658 arch_perf_update_userpage(event, userpg, now);
5666 EXPORT_SYMBOL_GPL(perf_event_update_userpage);
5668 static vm_fault_t perf_mmap_fault(struct vm_fault *vmf)
5670 struct perf_event *event = vmf->vma->vm_file->private_data;
5671 struct perf_buffer *rb;
5672 vm_fault_t ret = VM_FAULT_SIGBUS;
5674 if (vmf->flags & FAULT_FLAG_MKWRITE) {
5675 if (vmf->pgoff == 0)
5681 rb = rcu_dereference(event->rb);
5685 if (vmf->pgoff && (vmf->flags & FAULT_FLAG_WRITE))
5688 vmf->page = perf_mmap_to_page(rb, vmf->pgoff);
5692 get_page(vmf->page);
5693 vmf->page->mapping = vmf->vma->vm_file->f_mapping;
5694 vmf->page->index = vmf->pgoff;
5703 static void ring_buffer_attach(struct perf_event *event,
5704 struct perf_buffer *rb)
5706 struct perf_buffer *old_rb = NULL;
5707 unsigned long flags;
5711 * Should be impossible, we set this when removing
5712 * event->rb_entry and wait/clear when adding event->rb_entry.
5714 WARN_ON_ONCE(event->rcu_pending);
5717 spin_lock_irqsave(&old_rb->event_lock, flags);
5718 list_del_rcu(&event->rb_entry);
5719 spin_unlock_irqrestore(&old_rb->event_lock, flags);
5721 event->rcu_batches = get_state_synchronize_rcu();
5722 event->rcu_pending = 1;
5726 if (event->rcu_pending) {
5727 cond_synchronize_rcu(event->rcu_batches);
5728 event->rcu_pending = 0;
5731 spin_lock_irqsave(&rb->event_lock, flags);
5732 list_add_rcu(&event->rb_entry, &rb->event_list);
5733 spin_unlock_irqrestore(&rb->event_lock, flags);
5737 * Avoid racing with perf_mmap_close(AUX): stop the event
5738 * before swizzling the event::rb pointer; if it's getting
5739 * unmapped, its aux_mmap_count will be 0 and it won't
5740 * restart. See the comment in __perf_pmu_output_stop().
5742 * Data will inevitably be lost when set_output is done in
5743 * mid-air, but then again, whoever does it like this is
5744 * not in for the data anyway.
5747 perf_event_stop(event, 0);
5749 rcu_assign_pointer(event->rb, rb);
5752 ring_buffer_put(old_rb);
5754 * Since we detached before setting the new rb, so that we
5755 * could attach the new rb, we could have missed a wakeup.
5758 wake_up_all(&event->waitq);
5762 static void ring_buffer_wakeup(struct perf_event *event)
5764 struct perf_buffer *rb;
5767 rb = rcu_dereference(event->rb);
5769 list_for_each_entry_rcu(event, &rb->event_list, rb_entry)
5770 wake_up_all(&event->waitq);
5775 struct perf_buffer *ring_buffer_get(struct perf_event *event)
5777 struct perf_buffer *rb;
5780 rb = rcu_dereference(event->rb);
5782 if (!refcount_inc_not_zero(&rb->refcount))
5790 void ring_buffer_put(struct perf_buffer *rb)
5792 if (!refcount_dec_and_test(&rb->refcount))
5795 WARN_ON_ONCE(!list_empty(&rb->event_list));
5797 call_rcu(&rb->rcu_head, rb_free_rcu);
5800 static void perf_mmap_open(struct vm_area_struct *vma)
5802 struct perf_event *event = vma->vm_file->private_data;
5804 atomic_inc(&event->mmap_count);
5805 atomic_inc(&event->rb->mmap_count);
5808 atomic_inc(&event->rb->aux_mmap_count);
5810 if (event->pmu->event_mapped)
5811 event->pmu->event_mapped(event, vma->vm_mm);
5814 static void perf_pmu_output_stop(struct perf_event *event);
5817 * A buffer can be mmap()ed multiple times; either directly through the same
5818 * event, or through other events by use of perf_event_set_output().
5820 * In order to undo the VM accounting done by perf_mmap() we need to destroy
5821 * the buffer here, where we still have a VM context. This means we need
5822 * to detach all events redirecting to us.
5824 static void perf_mmap_close(struct vm_area_struct *vma)
5826 struct perf_event *event = vma->vm_file->private_data;
5828 struct perf_buffer *rb = ring_buffer_get(event);
5829 struct user_struct *mmap_user = rb->mmap_user;
5830 int mmap_locked = rb->mmap_locked;
5831 unsigned long size = perf_data_size(rb);
5833 if (event->pmu->event_unmapped)
5834 event->pmu->event_unmapped(event, vma->vm_mm);
5837 * rb->aux_mmap_count will always drop before rb->mmap_count and
5838 * event->mmap_count, so it is ok to use event->mmap_mutex to
5839 * serialize with perf_mmap here.
5841 if (rb_has_aux(rb) && vma->vm_pgoff == rb->aux_pgoff &&
5842 atomic_dec_and_mutex_lock(&rb->aux_mmap_count, &event->mmap_mutex)) {
5844 * Stop all AUX events that are writing to this buffer,
5845 * so that we can free its AUX pages and corresponding PMU
5846 * data. Note that after rb::aux_mmap_count dropped to zero,
5847 * they won't start any more (see perf_aux_output_begin()).
5849 perf_pmu_output_stop(event);
5851 /* now it's safe to free the pages */
5852 atomic_long_sub(rb->aux_nr_pages - rb->aux_mmap_locked, &mmap_user->locked_vm);
5853 atomic64_sub(rb->aux_mmap_locked, &vma->vm_mm->pinned_vm);
5855 /* this has to be the last one */
5857 WARN_ON_ONCE(refcount_read(&rb->aux_refcount));
5859 mutex_unlock(&event->mmap_mutex);
5862 atomic_dec(&rb->mmap_count);
5864 if (!atomic_dec_and_mutex_lock(&event->mmap_count, &event->mmap_mutex))
5867 ring_buffer_attach(event, NULL);
5868 mutex_unlock(&event->mmap_mutex);
5870 /* If there's still other mmap()s of this buffer, we're done. */
5871 if (atomic_read(&rb->mmap_count))
5875 * No other mmap()s, detach from all other events that might redirect
5876 * into the now unreachable buffer. Somewhat complicated by the
5877 * fact that rb::event_lock otherwise nests inside mmap_mutex.
5881 list_for_each_entry_rcu(event, &rb->event_list, rb_entry) {
5882 if (!atomic_long_inc_not_zero(&event->refcount)) {
5884 * This event is en-route to free_event() which will
5885 * detach it and remove it from the list.
5891 mutex_lock(&event->mmap_mutex);
5893 * Check we didn't race with perf_event_set_output() which can
5894 * swizzle the rb from under us while we were waiting to
5895 * acquire mmap_mutex.
5897 * If we find a different rb; ignore this event, a next
5898 * iteration will no longer find it on the list. We have to
5899 * still restart the iteration to make sure we're not now
5900 * iterating the wrong list.
5902 if (event->rb == rb)
5903 ring_buffer_attach(event, NULL);
5905 mutex_unlock(&event->mmap_mutex);
5909 * Restart the iteration; either we're on the wrong list or
5910 * destroyed its integrity by doing a deletion.
5917 * It could be there's still a few 0-ref events on the list; they'll
5918 * get cleaned up by free_event() -- they'll also still have their
5919 * ref on the rb and will free it whenever they are done with it.
5921 * Aside from that, this buffer is 'fully' detached and unmapped,
5922 * undo the VM accounting.
5925 atomic_long_sub((size >> PAGE_SHIFT) + 1 - mmap_locked,
5926 &mmap_user->locked_vm);
5927 atomic64_sub(mmap_locked, &vma->vm_mm->pinned_vm);
5928 free_uid(mmap_user);
5931 ring_buffer_put(rb); /* could be last */
5934 static const struct vm_operations_struct perf_mmap_vmops = {
5935 .open = perf_mmap_open,
5936 .close = perf_mmap_close, /* non mergeable */
5937 .fault = perf_mmap_fault,
5938 .page_mkwrite = perf_mmap_fault,
5941 static int perf_mmap(struct file *file, struct vm_area_struct *vma)
5943 struct perf_event *event = file->private_data;
5944 unsigned long user_locked, user_lock_limit;
5945 struct user_struct *user = current_user();
5946 struct perf_buffer *rb = NULL;
5947 unsigned long locked, lock_limit;
5948 unsigned long vma_size;
5949 unsigned long nr_pages;
5950 long user_extra = 0, extra = 0;
5951 int ret = 0, flags = 0;
5954 * Don't allow mmap() of inherited per-task counters. This would
5955 * create a performance issue due to all children writing to the
5958 if (event->cpu == -1 && event->attr.inherit)
5961 if (!(vma->vm_flags & VM_SHARED))
5964 ret = security_perf_event_read(event);
5968 vma_size = vma->vm_end - vma->vm_start;
5970 if (vma->vm_pgoff == 0) {
5971 nr_pages = (vma_size / PAGE_SIZE) - 1;
5974 * AUX area mapping: if rb->aux_nr_pages != 0, it's already
5975 * mapped, all subsequent mappings should have the same size
5976 * and offset. Must be above the normal perf buffer.
5978 u64 aux_offset, aux_size;
5983 nr_pages = vma_size / PAGE_SIZE;
5985 mutex_lock(&event->mmap_mutex);
5992 aux_offset = READ_ONCE(rb->user_page->aux_offset);
5993 aux_size = READ_ONCE(rb->user_page->aux_size);
5995 if (aux_offset < perf_data_size(rb) + PAGE_SIZE)
5998 if (aux_offset != vma->vm_pgoff << PAGE_SHIFT)
6001 /* already mapped with a different offset */
6002 if (rb_has_aux(rb) && rb->aux_pgoff != vma->vm_pgoff)
6005 if (aux_size != vma_size || aux_size != nr_pages * PAGE_SIZE)
6008 /* already mapped with a different size */
6009 if (rb_has_aux(rb) && rb->aux_nr_pages != nr_pages)
6012 if (!is_power_of_2(nr_pages))
6015 if (!atomic_inc_not_zero(&rb->mmap_count))
6018 if (rb_has_aux(rb)) {
6019 atomic_inc(&rb->aux_mmap_count);
6024 atomic_set(&rb->aux_mmap_count, 1);
6025 user_extra = nr_pages;
6031 * If we have rb pages ensure they're a power-of-two number, so we
6032 * can do bitmasks instead of modulo.
6034 if (nr_pages != 0 && !is_power_of_2(nr_pages))
6037 if (vma_size != PAGE_SIZE * (1 + nr_pages))
6040 WARN_ON_ONCE(event->ctx->parent_ctx);
6042 mutex_lock(&event->mmap_mutex);
6044 if (event->rb->nr_pages != nr_pages) {
6049 if (!atomic_inc_not_zero(&event->rb->mmap_count)) {
6051 * Raced against perf_mmap_close() through
6052 * perf_event_set_output(). Try again, hope for better
6055 mutex_unlock(&event->mmap_mutex);
6062 user_extra = nr_pages + 1;
6065 user_lock_limit = sysctl_perf_event_mlock >> (PAGE_SHIFT - 10);
6068 * Increase the limit linearly with more CPUs:
6070 user_lock_limit *= num_online_cpus();
6072 user_locked = atomic_long_read(&user->locked_vm);
6075 * sysctl_perf_event_mlock may have changed, so that
6076 * user->locked_vm > user_lock_limit
6078 if (user_locked > user_lock_limit)
6079 user_locked = user_lock_limit;
6080 user_locked += user_extra;
6082 if (user_locked > user_lock_limit) {
6084 * charge locked_vm until it hits user_lock_limit;
6085 * charge the rest from pinned_vm
6087 extra = user_locked - user_lock_limit;
6088 user_extra -= extra;
6091 lock_limit = rlimit(RLIMIT_MEMLOCK);
6092 lock_limit >>= PAGE_SHIFT;
6093 locked = atomic64_read(&vma->vm_mm->pinned_vm) + extra;
6095 if ((locked > lock_limit) && perf_is_paranoid() &&
6096 !capable(CAP_IPC_LOCK)) {
6101 WARN_ON(!rb && event->rb);
6103 if (vma->vm_flags & VM_WRITE)
6104 flags |= RING_BUFFER_WRITABLE;
6107 rb = rb_alloc(nr_pages,
6108 event->attr.watermark ? event->attr.wakeup_watermark : 0,
6116 atomic_set(&rb->mmap_count, 1);
6117 rb->mmap_user = get_current_user();
6118 rb->mmap_locked = extra;
6120 ring_buffer_attach(event, rb);
6122 perf_event_init_userpage(event);
6123 perf_event_update_userpage(event);
6125 ret = rb_alloc_aux(rb, event, vma->vm_pgoff, nr_pages,
6126 event->attr.aux_watermark, flags);
6128 rb->aux_mmap_locked = extra;
6133 atomic_long_add(user_extra, &user->locked_vm);
6134 atomic64_add(extra, &vma->vm_mm->pinned_vm);
6136 atomic_inc(&event->mmap_count);
6138 atomic_dec(&rb->mmap_count);
6141 mutex_unlock(&event->mmap_mutex);
6144 * Since pinned accounting is per vm we cannot allow fork() to copy our
6147 vma->vm_flags |= VM_DONTCOPY | VM_DONTEXPAND | VM_DONTDUMP;
6148 vma->vm_ops = &perf_mmap_vmops;
6150 if (event->pmu->event_mapped)
6151 event->pmu->event_mapped(event, vma->vm_mm);
6156 static int perf_fasync(int fd, struct file *filp, int on)
6158 struct inode *inode = file_inode(filp);
6159 struct perf_event *event = filp->private_data;
6163 retval = fasync_helper(fd, filp, on, &event->fasync);
6164 inode_unlock(inode);
6172 static const struct file_operations perf_fops = {
6173 .llseek = no_llseek,
6174 .release = perf_release,
6177 .unlocked_ioctl = perf_ioctl,
6178 .compat_ioctl = perf_compat_ioctl,
6180 .fasync = perf_fasync,
6186 * If there's data, ensure we set the poll() state and publish everything
6187 * to user-space before waking everybody up.
6190 static inline struct fasync_struct **perf_event_fasync(struct perf_event *event)
6192 /* only the parent has fasync state */
6194 event = event->parent;
6195 return &event->fasync;
6198 void perf_event_wakeup(struct perf_event *event)
6200 ring_buffer_wakeup(event);
6202 if (event->pending_kill) {
6203 kill_fasync(perf_event_fasync(event), SIGIO, event->pending_kill);
6204 event->pending_kill = 0;
6208 static void perf_pending_event_disable(struct perf_event *event)
6210 int cpu = READ_ONCE(event->pending_disable);
6215 if (cpu == smp_processor_id()) {
6216 WRITE_ONCE(event->pending_disable, -1);
6217 perf_event_disable_local(event);
6224 * perf_event_disable_inatomic()
6225 * @pending_disable = CPU-A;
6229 * @pending_disable = -1;
6232 * perf_event_disable_inatomic()
6233 * @pending_disable = CPU-B;
6234 * irq_work_queue(); // FAILS
6237 * perf_pending_event()
6239 * But the event runs on CPU-B and wants disabling there.
6241 irq_work_queue_on(&event->pending, cpu);
6244 static void perf_pending_event(struct irq_work *entry)
6246 struct perf_event *event = container_of(entry, struct perf_event, pending);
6249 rctx = perf_swevent_get_recursion_context();
6251 * If we 'fail' here, that's OK, it means recursion is already disabled
6252 * and we won't recurse 'further'.
6255 perf_pending_event_disable(event);
6257 if (event->pending_wakeup) {
6258 event->pending_wakeup = 0;
6259 perf_event_wakeup(event);
6263 perf_swevent_put_recursion_context(rctx);
6267 * We assume there is only KVM supporting the callbacks.
6268 * Later on, we might change it to a list if there is
6269 * another virtualization implementation supporting the callbacks.
6271 struct perf_guest_info_callbacks *perf_guest_cbs;
6273 int perf_register_guest_info_callbacks(struct perf_guest_info_callbacks *cbs)
6275 perf_guest_cbs = cbs;
6278 EXPORT_SYMBOL_GPL(perf_register_guest_info_callbacks);
6280 int perf_unregister_guest_info_callbacks(struct perf_guest_info_callbacks *cbs)
6282 perf_guest_cbs = NULL;
6285 EXPORT_SYMBOL_GPL(perf_unregister_guest_info_callbacks);
6288 perf_output_sample_regs(struct perf_output_handle *handle,
6289 struct pt_regs *regs, u64 mask)
6292 DECLARE_BITMAP(_mask, 64);
6294 bitmap_from_u64(_mask, mask);
6295 for_each_set_bit(bit, _mask, sizeof(mask) * BITS_PER_BYTE) {
6298 val = perf_reg_value(regs, bit);
6299 perf_output_put(handle, val);
6303 static void perf_sample_regs_user(struct perf_regs *regs_user,
6304 struct pt_regs *regs,
6305 struct pt_regs *regs_user_copy)
6307 if (user_mode(regs)) {
6308 regs_user->abi = perf_reg_abi(current);
6309 regs_user->regs = regs;
6310 } else if (!(current->flags & PF_KTHREAD)) {
6311 perf_get_regs_user(regs_user, regs, regs_user_copy);
6313 regs_user->abi = PERF_SAMPLE_REGS_ABI_NONE;
6314 regs_user->regs = NULL;
6318 static void perf_sample_regs_intr(struct perf_regs *regs_intr,
6319 struct pt_regs *regs)
6321 regs_intr->regs = regs;
6322 regs_intr->abi = perf_reg_abi(current);
6327 * Get remaining task size from user stack pointer.
6329 * It'd be better to take stack vma map and limit this more
6330 * precisely, but there's no way to get it safely under interrupt,
6331 * so using TASK_SIZE as limit.
6333 static u64 perf_ustack_task_size(struct pt_regs *regs)
6335 unsigned long addr = perf_user_stack_pointer(regs);
6337 if (!addr || addr >= TASK_SIZE)
6340 return TASK_SIZE - addr;
6344 perf_sample_ustack_size(u16 stack_size, u16 header_size,
6345 struct pt_regs *regs)
6349 /* No regs, no stack pointer, no dump. */
6354 * Check if we fit in with the requested stack size into the:
6356 * If we don't, we limit the size to the TASK_SIZE.
6358 * - remaining sample size
6359 * If we don't, we customize the stack size to
6360 * fit in to the remaining sample size.
6363 task_size = min((u64) USHRT_MAX, perf_ustack_task_size(regs));
6364 stack_size = min(stack_size, (u16) task_size);
6366 /* Current header size plus static size and dynamic size. */
6367 header_size += 2 * sizeof(u64);
6369 /* Do we fit in with the current stack dump size? */
6370 if ((u16) (header_size + stack_size) < header_size) {
6372 * If we overflow the maximum size for the sample,
6373 * we customize the stack dump size to fit in.
6375 stack_size = USHRT_MAX - header_size - sizeof(u64);
6376 stack_size = round_up(stack_size, sizeof(u64));
6383 perf_output_sample_ustack(struct perf_output_handle *handle, u64 dump_size,
6384 struct pt_regs *regs)
6386 /* Case of a kernel thread, nothing to dump */
6389 perf_output_put(handle, size);
6399 * - the size requested by user or the best one we can fit
6400 * in to the sample max size
6402 * - user stack dump data
6404 * - the actual dumped size
6408 perf_output_put(handle, dump_size);
6411 sp = perf_user_stack_pointer(regs);
6414 rem = __output_copy_user(handle, (void *) sp, dump_size);
6416 dyn_size = dump_size - rem;
6418 perf_output_skip(handle, rem);
6421 perf_output_put(handle, dyn_size);
6425 static unsigned long perf_prepare_sample_aux(struct perf_event *event,
6426 struct perf_sample_data *data,
6429 struct perf_event *sampler = event->aux_event;
6430 struct perf_buffer *rb;
6437 if (WARN_ON_ONCE(READ_ONCE(sampler->state) != PERF_EVENT_STATE_ACTIVE))
6440 if (WARN_ON_ONCE(READ_ONCE(sampler->oncpu) != smp_processor_id()))
6443 rb = ring_buffer_get(sampler->parent ? sampler->parent : sampler);
6448 * If this is an NMI hit inside sampling code, don't take
6449 * the sample. See also perf_aux_sample_output().
6451 if (READ_ONCE(rb->aux_in_sampling)) {
6454 size = min_t(size_t, size, perf_aux_size(rb));
6455 data->aux_size = ALIGN(size, sizeof(u64));
6457 ring_buffer_put(rb);
6460 return data->aux_size;
6463 long perf_pmu_snapshot_aux(struct perf_buffer *rb,
6464 struct perf_event *event,
6465 struct perf_output_handle *handle,
6468 unsigned long flags;
6472 * Normal ->start()/->stop() callbacks run in IRQ mode in scheduler
6473 * paths. If we start calling them in NMI context, they may race with
6474 * the IRQ ones, that is, for example, re-starting an event that's just
6475 * been stopped, which is why we're using a separate callback that
6476 * doesn't change the event state.
6478 * IRQs need to be disabled to prevent IPIs from racing with us.
6480 local_irq_save(flags);
6482 * Guard against NMI hits inside the critical section;
6483 * see also perf_prepare_sample_aux().
6485 WRITE_ONCE(rb->aux_in_sampling, 1);
6488 ret = event->pmu->snapshot_aux(event, handle, size);
6491 WRITE_ONCE(rb->aux_in_sampling, 0);
6492 local_irq_restore(flags);
6497 static void perf_aux_sample_output(struct perf_event *event,
6498 struct perf_output_handle *handle,
6499 struct perf_sample_data *data)
6501 struct perf_event *sampler = event->aux_event;
6502 struct perf_buffer *rb;
6506 if (WARN_ON_ONCE(!sampler || !data->aux_size))
6509 rb = ring_buffer_get(sampler->parent ? sampler->parent : sampler);
6513 size = perf_pmu_snapshot_aux(rb, sampler, handle, data->aux_size);
6516 * An error here means that perf_output_copy() failed (returned a
6517 * non-zero surplus that it didn't copy), which in its current
6518 * enlightened implementation is not possible. If that changes, we'd
6521 if (WARN_ON_ONCE(size < 0))
6525 * The pad comes from ALIGN()ing data->aux_size up to u64 in
6526 * perf_prepare_sample_aux(), so should not be more than that.
6528 pad = data->aux_size - size;
6529 if (WARN_ON_ONCE(pad >= sizeof(u64)))
6534 perf_output_copy(handle, &zero, pad);
6538 ring_buffer_put(rb);
6541 static void __perf_event_header__init_id(struct perf_event_header *header,
6542 struct perf_sample_data *data,
6543 struct perf_event *event)
6545 u64 sample_type = event->attr.sample_type;
6547 data->type = sample_type;
6548 header->size += event->id_header_size;
6550 if (sample_type & PERF_SAMPLE_TID) {
6551 /* namespace issues */
6552 data->tid_entry.pid = perf_event_pid(event, current);
6553 data->tid_entry.tid = perf_event_tid(event, current);
6556 if (sample_type & PERF_SAMPLE_TIME)
6557 data->time = perf_event_clock(event);
6559 if (sample_type & (PERF_SAMPLE_ID | PERF_SAMPLE_IDENTIFIER))
6560 data->id = primary_event_id(event);
6562 if (sample_type & PERF_SAMPLE_STREAM_ID)
6563 data->stream_id = event->id;
6565 if (sample_type & PERF_SAMPLE_CPU) {
6566 data->cpu_entry.cpu = raw_smp_processor_id();
6567 data->cpu_entry.reserved = 0;
6571 void perf_event_header__init_id(struct perf_event_header *header,
6572 struct perf_sample_data *data,
6573 struct perf_event *event)
6575 if (event->attr.sample_id_all)
6576 __perf_event_header__init_id(header, data, event);
6579 static void __perf_event__output_id_sample(struct perf_output_handle *handle,
6580 struct perf_sample_data *data)
6582 u64 sample_type = data->type;
6584 if (sample_type & PERF_SAMPLE_TID)
6585 perf_output_put(handle, data->tid_entry);
6587 if (sample_type & PERF_SAMPLE_TIME)
6588 perf_output_put(handle, data->time);
6590 if (sample_type & PERF_SAMPLE_ID)
6591 perf_output_put(handle, data->id);
6593 if (sample_type & PERF_SAMPLE_STREAM_ID)
6594 perf_output_put(handle, data->stream_id);
6596 if (sample_type & PERF_SAMPLE_CPU)
6597 perf_output_put(handle, data->cpu_entry);
6599 if (sample_type & PERF_SAMPLE_IDENTIFIER)
6600 perf_output_put(handle, data->id);
6603 void perf_event__output_id_sample(struct perf_event *event,
6604 struct perf_output_handle *handle,
6605 struct perf_sample_data *sample)
6607 if (event->attr.sample_id_all)
6608 __perf_event__output_id_sample(handle, sample);
6611 static void perf_output_read_one(struct perf_output_handle *handle,
6612 struct perf_event *event,
6613 u64 enabled, u64 running)
6615 u64 read_format = event->attr.read_format;
6619 values[n++] = perf_event_count(event);
6620 if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED) {
6621 values[n++] = enabled +
6622 atomic64_read(&event->child_total_time_enabled);
6624 if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING) {
6625 values[n++] = running +
6626 atomic64_read(&event->child_total_time_running);
6628 if (read_format & PERF_FORMAT_ID)
6629 values[n++] = primary_event_id(event);
6631 __output_copy(handle, values, n * sizeof(u64));
6634 static void perf_output_read_group(struct perf_output_handle *handle,
6635 struct perf_event *event,
6636 u64 enabled, u64 running)
6638 struct perf_event *leader = event->group_leader, *sub;
6639 u64 read_format = event->attr.read_format;
6643 values[n++] = 1 + leader->nr_siblings;
6645 if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED)
6646 values[n++] = enabled;
6648 if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING)
6649 values[n++] = running;
6651 if ((leader != event) &&
6652 (leader->state == PERF_EVENT_STATE_ACTIVE))
6653 leader->pmu->read(leader);
6655 values[n++] = perf_event_count(leader);
6656 if (read_format & PERF_FORMAT_ID)
6657 values[n++] = primary_event_id(leader);
6659 __output_copy(handle, values, n * sizeof(u64));
6661 for_each_sibling_event(sub, leader) {
6664 if ((sub != event) &&
6665 (sub->state == PERF_EVENT_STATE_ACTIVE))
6666 sub->pmu->read(sub);
6668 values[n++] = perf_event_count(sub);
6669 if (read_format & PERF_FORMAT_ID)
6670 values[n++] = primary_event_id(sub);
6672 __output_copy(handle, values, n * sizeof(u64));
6676 #define PERF_FORMAT_TOTAL_TIMES (PERF_FORMAT_TOTAL_TIME_ENABLED|\
6677 PERF_FORMAT_TOTAL_TIME_RUNNING)
6680 * XXX PERF_SAMPLE_READ vs inherited events seems difficult.
6682 * The problem is that its both hard and excessively expensive to iterate the
6683 * child list, not to mention that its impossible to IPI the children running
6684 * on another CPU, from interrupt/NMI context.
6686 static void perf_output_read(struct perf_output_handle *handle,
6687 struct perf_event *event)
6689 u64 enabled = 0, running = 0, now;
6690 u64 read_format = event->attr.read_format;
6693 * compute total_time_enabled, total_time_running
6694 * based on snapshot values taken when the event
6695 * was last scheduled in.
6697 * we cannot simply called update_context_time()
6698 * because of locking issue as we are called in
6701 if (read_format & PERF_FORMAT_TOTAL_TIMES)
6702 calc_timer_values(event, &now, &enabled, &running);
6704 if (event->attr.read_format & PERF_FORMAT_GROUP)
6705 perf_output_read_group(handle, event, enabled, running);
6707 perf_output_read_one(handle, event, enabled, running);
6710 static inline bool perf_sample_save_hw_index(struct perf_event *event)
6712 return event->attr.branch_sample_type & PERF_SAMPLE_BRANCH_HW_INDEX;
6715 void perf_output_sample(struct perf_output_handle *handle,
6716 struct perf_event_header *header,
6717 struct perf_sample_data *data,
6718 struct perf_event *event)
6720 u64 sample_type = data->type;
6722 perf_output_put(handle, *header);
6724 if (sample_type & PERF_SAMPLE_IDENTIFIER)
6725 perf_output_put(handle, data->id);
6727 if (sample_type & PERF_SAMPLE_IP)
6728 perf_output_put(handle, data->ip);
6730 if (sample_type & PERF_SAMPLE_TID)
6731 perf_output_put(handle, data->tid_entry);
6733 if (sample_type & PERF_SAMPLE_TIME)
6734 perf_output_put(handle, data->time);
6736 if (sample_type & PERF_SAMPLE_ADDR)
6737 perf_output_put(handle, data->addr);
6739 if (sample_type & PERF_SAMPLE_ID)
6740 perf_output_put(handle, data->id);
6742 if (sample_type & PERF_SAMPLE_STREAM_ID)
6743 perf_output_put(handle, data->stream_id);
6745 if (sample_type & PERF_SAMPLE_CPU)
6746 perf_output_put(handle, data->cpu_entry);
6748 if (sample_type & PERF_SAMPLE_PERIOD)
6749 perf_output_put(handle, data->period);
6751 if (sample_type & PERF_SAMPLE_READ)
6752 perf_output_read(handle, event);
6754 if (sample_type & PERF_SAMPLE_CALLCHAIN) {
6757 size += data->callchain->nr;
6758 size *= sizeof(u64);
6759 __output_copy(handle, data->callchain, size);
6762 if (sample_type & PERF_SAMPLE_RAW) {
6763 struct perf_raw_record *raw = data->raw;
6766 struct perf_raw_frag *frag = &raw->frag;
6768 perf_output_put(handle, raw->size);
6771 __output_custom(handle, frag->copy,
6772 frag->data, frag->size);
6774 __output_copy(handle, frag->data,
6777 if (perf_raw_frag_last(frag))
6782 __output_skip(handle, NULL, frag->pad);
6788 .size = sizeof(u32),
6791 perf_output_put(handle, raw);
6795 if (sample_type & PERF_SAMPLE_BRANCH_STACK) {
6796 if (data->br_stack) {
6799 size = data->br_stack->nr
6800 * sizeof(struct perf_branch_entry);
6802 perf_output_put(handle, data->br_stack->nr);
6803 if (perf_sample_save_hw_index(event))
6804 perf_output_put(handle, data->br_stack->hw_idx);
6805 perf_output_copy(handle, data->br_stack->entries, size);
6808 * we always store at least the value of nr
6811 perf_output_put(handle, nr);
6815 if (sample_type & PERF_SAMPLE_REGS_USER) {
6816 u64 abi = data->regs_user.abi;
6819 * If there are no regs to dump, notice it through
6820 * first u64 being zero (PERF_SAMPLE_REGS_ABI_NONE).
6822 perf_output_put(handle, abi);
6825 u64 mask = event->attr.sample_regs_user;
6826 perf_output_sample_regs(handle,
6827 data->regs_user.regs,
6832 if (sample_type & PERF_SAMPLE_STACK_USER) {
6833 perf_output_sample_ustack(handle,
6834 data->stack_user_size,
6835 data->regs_user.regs);
6838 if (sample_type & PERF_SAMPLE_WEIGHT)
6839 perf_output_put(handle, data->weight);
6841 if (sample_type & PERF_SAMPLE_DATA_SRC)
6842 perf_output_put(handle, data->data_src.val);
6844 if (sample_type & PERF_SAMPLE_TRANSACTION)
6845 perf_output_put(handle, data->txn);
6847 if (sample_type & PERF_SAMPLE_REGS_INTR) {
6848 u64 abi = data->regs_intr.abi;
6850 * If there are no regs to dump, notice it through
6851 * first u64 being zero (PERF_SAMPLE_REGS_ABI_NONE).
6853 perf_output_put(handle, abi);
6856 u64 mask = event->attr.sample_regs_intr;
6858 perf_output_sample_regs(handle,
6859 data->regs_intr.regs,
6864 if (sample_type & PERF_SAMPLE_PHYS_ADDR)
6865 perf_output_put(handle, data->phys_addr);
6867 if (sample_type & PERF_SAMPLE_AUX) {
6868 perf_output_put(handle, data->aux_size);
6871 perf_aux_sample_output(event, handle, data);
6874 if (!event->attr.watermark) {
6875 int wakeup_events = event->attr.wakeup_events;
6877 if (wakeup_events) {
6878 struct perf_buffer *rb = handle->rb;
6879 int events = local_inc_return(&rb->events);
6881 if (events >= wakeup_events) {
6882 local_sub(wakeup_events, &rb->events);
6883 local_inc(&rb->wakeup);
6889 static u64 perf_virt_to_phys(u64 virt)
6892 struct page *p = NULL;
6897 if (virt >= TASK_SIZE) {
6898 /* If it's vmalloc()d memory, leave phys_addr as 0 */
6899 if (virt_addr_valid((void *)(uintptr_t)virt) &&
6900 !(virt >= VMALLOC_START && virt < VMALLOC_END))
6901 phys_addr = (u64)virt_to_phys((void *)(uintptr_t)virt);
6904 * Walking the pages tables for user address.
6905 * Interrupts are disabled, so it prevents any tear down
6906 * of the page tables.
6907 * Try IRQ-safe __get_user_pages_fast first.
6908 * If failed, leave phys_addr as 0.
6910 if ((current->mm != NULL) &&
6911 (__get_user_pages_fast(virt, 1, 0, &p) == 1))
6912 phys_addr = page_to_phys(p) + virt % PAGE_SIZE;
6921 static struct perf_callchain_entry __empty_callchain = { .nr = 0, };
6923 struct perf_callchain_entry *
6924 perf_callchain(struct perf_event *event, struct pt_regs *regs)
6926 bool kernel = !event->attr.exclude_callchain_kernel;
6927 bool user = !event->attr.exclude_callchain_user;
6928 /* Disallow cross-task user callchains. */
6929 bool crosstask = event->ctx->task && event->ctx->task != current;
6930 const u32 max_stack = event->attr.sample_max_stack;
6931 struct perf_callchain_entry *callchain;
6933 if (!kernel && !user)
6934 return &__empty_callchain;
6936 callchain = get_perf_callchain(regs, 0, kernel, user,
6937 max_stack, crosstask, true);
6938 return callchain ?: &__empty_callchain;
6941 void perf_prepare_sample(struct perf_event_header *header,
6942 struct perf_sample_data *data,
6943 struct perf_event *event,
6944 struct pt_regs *regs)
6946 u64 sample_type = event->attr.sample_type;
6948 header->type = PERF_RECORD_SAMPLE;
6949 header->size = sizeof(*header) + event->header_size;
6952 header->misc |= perf_misc_flags(regs);
6954 __perf_event_header__init_id(header, data, event);
6956 if (sample_type & PERF_SAMPLE_IP)
6957 data->ip = perf_instruction_pointer(regs);
6959 if (sample_type & PERF_SAMPLE_CALLCHAIN) {
6962 if (!(sample_type & __PERF_SAMPLE_CALLCHAIN_EARLY))
6963 data->callchain = perf_callchain(event, regs);
6965 size += data->callchain->nr;
6967 header->size += size * sizeof(u64);
6970 if (sample_type & PERF_SAMPLE_RAW) {
6971 struct perf_raw_record *raw = data->raw;
6975 struct perf_raw_frag *frag = &raw->frag;
6980 if (perf_raw_frag_last(frag))
6985 size = round_up(sum + sizeof(u32), sizeof(u64));
6986 raw->size = size - sizeof(u32);
6987 frag->pad = raw->size - sum;
6992 header->size += size;
6995 if (sample_type & PERF_SAMPLE_BRANCH_STACK) {
6996 int size = sizeof(u64); /* nr */
6997 if (data->br_stack) {
6998 if (perf_sample_save_hw_index(event))
6999 size += sizeof(u64);
7001 size += data->br_stack->nr
7002 * sizeof(struct perf_branch_entry);
7004 header->size += size;
7007 if (sample_type & (PERF_SAMPLE_REGS_USER | PERF_SAMPLE_STACK_USER))
7008 perf_sample_regs_user(&data->regs_user, regs,
7009 &data->regs_user_copy);
7011 if (sample_type & PERF_SAMPLE_REGS_USER) {
7012 /* regs dump ABI info */
7013 int size = sizeof(u64);
7015 if (data->regs_user.regs) {
7016 u64 mask = event->attr.sample_regs_user;
7017 size += hweight64(mask) * sizeof(u64);
7020 header->size += size;
7023 if (sample_type & PERF_SAMPLE_STACK_USER) {
7025 * Either we need PERF_SAMPLE_STACK_USER bit to be always
7026 * processed as the last one or have additional check added
7027 * in case new sample type is added, because we could eat
7028 * up the rest of the sample size.
7030 u16 stack_size = event->attr.sample_stack_user;
7031 u16 size = sizeof(u64);
7033 stack_size = perf_sample_ustack_size(stack_size, header->size,
7034 data->regs_user.regs);
7037 * If there is something to dump, add space for the dump
7038 * itself and for the field that tells the dynamic size,
7039 * which is how many have been actually dumped.
7042 size += sizeof(u64) + stack_size;
7044 data->stack_user_size = stack_size;
7045 header->size += size;
7048 if (sample_type & PERF_SAMPLE_REGS_INTR) {
7049 /* regs dump ABI info */
7050 int size = sizeof(u64);
7052 perf_sample_regs_intr(&data->regs_intr, regs);
7054 if (data->regs_intr.regs) {
7055 u64 mask = event->attr.sample_regs_intr;
7057 size += hweight64(mask) * sizeof(u64);
7060 header->size += size;
7063 if (sample_type & PERF_SAMPLE_PHYS_ADDR)
7064 data->phys_addr = perf_virt_to_phys(data->addr);
7066 if (sample_type & PERF_SAMPLE_AUX) {
7069 header->size += sizeof(u64); /* size */
7072 * Given the 16bit nature of header::size, an AUX sample can
7073 * easily overflow it, what with all the preceding sample bits.
7074 * Make sure this doesn't happen by using up to U16_MAX bytes
7075 * per sample in total (rounded down to 8 byte boundary).
7077 size = min_t(size_t, U16_MAX - header->size,
7078 event->attr.aux_sample_size);
7079 size = rounddown(size, 8);
7080 size = perf_prepare_sample_aux(event, data, size);
7082 WARN_ON_ONCE(size + header->size > U16_MAX);
7083 header->size += size;
7086 * If you're adding more sample types here, you likely need to do
7087 * something about the overflowing header::size, like repurpose the
7088 * lowest 3 bits of size, which should be always zero at the moment.
7089 * This raises a more important question, do we really need 512k sized
7090 * samples and why, so good argumentation is in order for whatever you
7093 WARN_ON_ONCE(header->size & 7);
7096 static __always_inline int
7097 __perf_event_output(struct perf_event *event,
7098 struct perf_sample_data *data,
7099 struct pt_regs *regs,
7100 int (*output_begin)(struct perf_output_handle *,
7101 struct perf_event *,
7104 struct perf_output_handle handle;
7105 struct perf_event_header header;
7108 /* protect the callchain buffers */
7111 perf_prepare_sample(&header, data, event, regs);
7113 err = output_begin(&handle, event, header.size);
7117 perf_output_sample(&handle, &header, data, event);
7119 perf_output_end(&handle);
7127 perf_event_output_forward(struct perf_event *event,
7128 struct perf_sample_data *data,
7129 struct pt_regs *regs)
7131 __perf_event_output(event, data, regs, perf_output_begin_forward);
7135 perf_event_output_backward(struct perf_event *event,
7136 struct perf_sample_data *data,
7137 struct pt_regs *regs)
7139 __perf_event_output(event, data, regs, perf_output_begin_backward);
7143 perf_event_output(struct perf_event *event,
7144 struct perf_sample_data *data,
7145 struct pt_regs *regs)
7147 return __perf_event_output(event, data, regs, perf_output_begin);
7154 struct perf_read_event {
7155 struct perf_event_header header;
7162 perf_event_read_event(struct perf_event *event,
7163 struct task_struct *task)
7165 struct perf_output_handle handle;
7166 struct perf_sample_data sample;
7167 struct perf_read_event read_event = {
7169 .type = PERF_RECORD_READ,
7171 .size = sizeof(read_event) + event->read_size,
7173 .pid = perf_event_pid(event, task),
7174 .tid = perf_event_tid(event, task),
7178 perf_event_header__init_id(&read_event.header, &sample, event);
7179 ret = perf_output_begin(&handle, event, read_event.header.size);
7183 perf_output_put(&handle, read_event);
7184 perf_output_read(&handle, event);
7185 perf_event__output_id_sample(event, &handle, &sample);
7187 perf_output_end(&handle);
7190 typedef void (perf_iterate_f)(struct perf_event *event, void *data);
7193 perf_iterate_ctx(struct perf_event_context *ctx,
7194 perf_iterate_f output,
7195 void *data, bool all)
7197 struct perf_event *event;
7199 list_for_each_entry_rcu(event, &ctx->event_list, event_entry) {
7201 if (event->state < PERF_EVENT_STATE_INACTIVE)
7203 if (!event_filter_match(event))
7207 output(event, data);
7211 static void perf_iterate_sb_cpu(perf_iterate_f output, void *data)
7213 struct pmu_event_list *pel = this_cpu_ptr(&pmu_sb_events);
7214 struct perf_event *event;
7216 list_for_each_entry_rcu(event, &pel->list, sb_list) {
7218 * Skip events that are not fully formed yet; ensure that
7219 * if we observe event->ctx, both event and ctx will be
7220 * complete enough. See perf_install_in_context().
7222 if (!smp_load_acquire(&event->ctx))
7225 if (event->state < PERF_EVENT_STATE_INACTIVE)
7227 if (!event_filter_match(event))
7229 output(event, data);
7234 * Iterate all events that need to receive side-band events.
7236 * For new callers; ensure that account_pmu_sb_event() includes
7237 * your event, otherwise it might not get delivered.
7240 perf_iterate_sb(perf_iterate_f output, void *data,
7241 struct perf_event_context *task_ctx)
7243 struct perf_event_context *ctx;
7250 * If we have task_ctx != NULL we only notify the task context itself.
7251 * The task_ctx is set only for EXIT events before releasing task
7255 perf_iterate_ctx(task_ctx, output, data, false);
7259 perf_iterate_sb_cpu(output, data);
7261 for_each_task_context_nr(ctxn) {
7262 ctx = rcu_dereference(current->perf_event_ctxp[ctxn]);
7264 perf_iterate_ctx(ctx, output, data, false);
7272 * Clear all file-based filters at exec, they'll have to be
7273 * re-instated when/if these objects are mmapped again.
7275 static void perf_event_addr_filters_exec(struct perf_event *event, void *data)
7277 struct perf_addr_filters_head *ifh = perf_event_addr_filters(event);
7278 struct perf_addr_filter *filter;
7279 unsigned int restart = 0, count = 0;
7280 unsigned long flags;
7282 if (!has_addr_filter(event))
7285 raw_spin_lock_irqsave(&ifh->lock, flags);
7286 list_for_each_entry(filter, &ifh->list, entry) {
7287 if (filter->path.dentry) {
7288 event->addr_filter_ranges[count].start = 0;
7289 event->addr_filter_ranges[count].size = 0;
7297 event->addr_filters_gen++;
7298 raw_spin_unlock_irqrestore(&ifh->lock, flags);
7301 perf_event_stop(event, 1);
7304 void perf_event_exec(void)
7306 struct perf_event_context *ctx;
7310 for_each_task_context_nr(ctxn) {
7311 ctx = current->perf_event_ctxp[ctxn];
7315 perf_event_enable_on_exec(ctxn);
7317 perf_iterate_ctx(ctx, perf_event_addr_filters_exec, NULL,
7323 struct remote_output {
7324 struct perf_buffer *rb;
7328 static void __perf_event_output_stop(struct perf_event *event, void *data)
7330 struct perf_event *parent = event->parent;
7331 struct remote_output *ro = data;
7332 struct perf_buffer *rb = ro->rb;
7333 struct stop_event_data sd = {
7337 if (!has_aux(event))
7344 * In case of inheritance, it will be the parent that links to the
7345 * ring-buffer, but it will be the child that's actually using it.
7347 * We are using event::rb to determine if the event should be stopped,
7348 * however this may race with ring_buffer_attach() (through set_output),
7349 * which will make us skip the event that actually needs to be stopped.
7350 * So ring_buffer_attach() has to stop an aux event before re-assigning
7353 if (rcu_dereference(parent->rb) == rb)
7354 ro->err = __perf_event_stop(&sd);
7357 static int __perf_pmu_output_stop(void *info)
7359 struct perf_event *event = info;
7360 struct pmu *pmu = event->ctx->pmu;
7361 struct perf_cpu_context *cpuctx = this_cpu_ptr(pmu->pmu_cpu_context);
7362 struct remote_output ro = {
7367 perf_iterate_ctx(&cpuctx->ctx, __perf_event_output_stop, &ro, false);
7368 if (cpuctx->task_ctx)
7369 perf_iterate_ctx(cpuctx->task_ctx, __perf_event_output_stop,
7376 static void perf_pmu_output_stop(struct perf_event *event)
7378 struct perf_event *iter;
7383 list_for_each_entry_rcu(iter, &event->rb->event_list, rb_entry) {
7385 * For per-CPU events, we need to make sure that neither they
7386 * nor their children are running; for cpu==-1 events it's
7387 * sufficient to stop the event itself if it's active, since
7388 * it can't have children.
7392 cpu = READ_ONCE(iter->oncpu);
7397 err = cpu_function_call(cpu, __perf_pmu_output_stop, event);
7398 if (err == -EAGAIN) {
7407 * task tracking -- fork/exit
7409 * enabled by: attr.comm | attr.mmap | attr.mmap2 | attr.mmap_data | attr.task
7412 struct perf_task_event {
7413 struct task_struct *task;
7414 struct perf_event_context *task_ctx;
7417 struct perf_event_header header;
7427 static int perf_event_task_match(struct perf_event *event)
7429 return event->attr.comm || event->attr.mmap ||
7430 event->attr.mmap2 || event->attr.mmap_data ||
7434 static void perf_event_task_output(struct perf_event *event,
7437 struct perf_task_event *task_event = data;
7438 struct perf_output_handle handle;
7439 struct perf_sample_data sample;
7440 struct task_struct *task = task_event->task;
7441 int ret, size = task_event->event_id.header.size;
7443 if (!perf_event_task_match(event))
7446 perf_event_header__init_id(&task_event->event_id.header, &sample, event);
7448 ret = perf_output_begin(&handle, event,
7449 task_event->event_id.header.size);
7453 task_event->event_id.pid = perf_event_pid(event, task);
7454 task_event->event_id.ppid = perf_event_pid(event, current);
7456 task_event->event_id.tid = perf_event_tid(event, task);
7457 task_event->event_id.ptid = perf_event_tid(event, current);
7459 task_event->event_id.time = perf_event_clock(event);
7461 perf_output_put(&handle, task_event->event_id);
7463 perf_event__output_id_sample(event, &handle, &sample);
7465 perf_output_end(&handle);
7467 task_event->event_id.header.size = size;
7470 static void perf_event_task(struct task_struct *task,
7471 struct perf_event_context *task_ctx,
7474 struct perf_task_event task_event;
7476 if (!atomic_read(&nr_comm_events) &&
7477 !atomic_read(&nr_mmap_events) &&
7478 !atomic_read(&nr_task_events))
7481 task_event = (struct perf_task_event){
7483 .task_ctx = task_ctx,
7486 .type = new ? PERF_RECORD_FORK : PERF_RECORD_EXIT,
7488 .size = sizeof(task_event.event_id),
7498 perf_iterate_sb(perf_event_task_output,
7503 void perf_event_fork(struct task_struct *task)
7505 perf_event_task(task, NULL, 1);
7506 perf_event_namespaces(task);
7513 struct perf_comm_event {
7514 struct task_struct *task;
7519 struct perf_event_header header;
7526 static int perf_event_comm_match(struct perf_event *event)
7528 return event->attr.comm;
7531 static void perf_event_comm_output(struct perf_event *event,
7534 struct perf_comm_event *comm_event = data;
7535 struct perf_output_handle handle;
7536 struct perf_sample_data sample;
7537 int size = comm_event->event_id.header.size;
7540 if (!perf_event_comm_match(event))
7543 perf_event_header__init_id(&comm_event->event_id.header, &sample, event);
7544 ret = perf_output_begin(&handle, event,
7545 comm_event->event_id.header.size);
7550 comm_event->event_id.pid = perf_event_pid(event, comm_event->task);
7551 comm_event->event_id.tid = perf_event_tid(event, comm_event->task);
7553 perf_output_put(&handle, comm_event->event_id);
7554 __output_copy(&handle, comm_event->comm,
7555 comm_event->comm_size);
7557 perf_event__output_id_sample(event, &handle, &sample);
7559 perf_output_end(&handle);
7561 comm_event->event_id.header.size = size;
7564 static void perf_event_comm_event(struct perf_comm_event *comm_event)
7566 char comm[TASK_COMM_LEN];
7569 memset(comm, 0, sizeof(comm));
7570 strlcpy(comm, comm_event->task->comm, sizeof(comm));
7571 size = ALIGN(strlen(comm)+1, sizeof(u64));
7573 comm_event->comm = comm;
7574 comm_event->comm_size = size;
7576 comm_event->event_id.header.size = sizeof(comm_event->event_id) + size;
7578 perf_iterate_sb(perf_event_comm_output,
7583 void perf_event_comm(struct task_struct *task, bool exec)
7585 struct perf_comm_event comm_event;
7587 if (!atomic_read(&nr_comm_events))
7590 comm_event = (struct perf_comm_event){
7596 .type = PERF_RECORD_COMM,
7597 .misc = exec ? PERF_RECORD_MISC_COMM_EXEC : 0,
7605 perf_event_comm_event(&comm_event);
7609 * namespaces tracking
7612 struct perf_namespaces_event {
7613 struct task_struct *task;
7616 struct perf_event_header header;
7621 struct perf_ns_link_info link_info[NR_NAMESPACES];
7625 static int perf_event_namespaces_match(struct perf_event *event)
7627 return event->attr.namespaces;
7630 static void perf_event_namespaces_output(struct perf_event *event,
7633 struct perf_namespaces_event *namespaces_event = data;
7634 struct perf_output_handle handle;
7635 struct perf_sample_data sample;
7636 u16 header_size = namespaces_event->event_id.header.size;
7639 if (!perf_event_namespaces_match(event))
7642 perf_event_header__init_id(&namespaces_event->event_id.header,
7644 ret = perf_output_begin(&handle, event,
7645 namespaces_event->event_id.header.size);
7649 namespaces_event->event_id.pid = perf_event_pid(event,
7650 namespaces_event->task);
7651 namespaces_event->event_id.tid = perf_event_tid(event,
7652 namespaces_event->task);
7654 perf_output_put(&handle, namespaces_event->event_id);
7656 perf_event__output_id_sample(event, &handle, &sample);
7658 perf_output_end(&handle);
7660 namespaces_event->event_id.header.size = header_size;
7663 static void perf_fill_ns_link_info(struct perf_ns_link_info *ns_link_info,
7664 struct task_struct *task,
7665 const struct proc_ns_operations *ns_ops)
7667 struct path ns_path;
7668 struct inode *ns_inode;
7671 error = ns_get_path(&ns_path, task, ns_ops);
7673 ns_inode = ns_path.dentry->d_inode;
7674 ns_link_info->dev = new_encode_dev(ns_inode->i_sb->s_dev);
7675 ns_link_info->ino = ns_inode->i_ino;
7680 void perf_event_namespaces(struct task_struct *task)
7682 struct perf_namespaces_event namespaces_event;
7683 struct perf_ns_link_info *ns_link_info;
7685 if (!atomic_read(&nr_namespaces_events))
7688 namespaces_event = (struct perf_namespaces_event){
7692 .type = PERF_RECORD_NAMESPACES,
7694 .size = sizeof(namespaces_event.event_id),
7698 .nr_namespaces = NR_NAMESPACES,
7699 /* .link_info[NR_NAMESPACES] */
7703 ns_link_info = namespaces_event.event_id.link_info;
7705 perf_fill_ns_link_info(&ns_link_info[MNT_NS_INDEX],
7706 task, &mntns_operations);
7708 #ifdef CONFIG_USER_NS
7709 perf_fill_ns_link_info(&ns_link_info[USER_NS_INDEX],
7710 task, &userns_operations);
7712 #ifdef CONFIG_NET_NS
7713 perf_fill_ns_link_info(&ns_link_info[NET_NS_INDEX],
7714 task, &netns_operations);
7716 #ifdef CONFIG_UTS_NS
7717 perf_fill_ns_link_info(&ns_link_info[UTS_NS_INDEX],
7718 task, &utsns_operations);
7720 #ifdef CONFIG_IPC_NS
7721 perf_fill_ns_link_info(&ns_link_info[IPC_NS_INDEX],
7722 task, &ipcns_operations);
7724 #ifdef CONFIG_PID_NS
7725 perf_fill_ns_link_info(&ns_link_info[PID_NS_INDEX],
7726 task, &pidns_operations);
7728 #ifdef CONFIG_CGROUPS
7729 perf_fill_ns_link_info(&ns_link_info[CGROUP_NS_INDEX],
7730 task, &cgroupns_operations);
7733 perf_iterate_sb(perf_event_namespaces_output,
7742 struct perf_mmap_event {
7743 struct vm_area_struct *vma;
7745 const char *file_name;
7753 struct perf_event_header header;
7763 static int perf_event_mmap_match(struct perf_event *event,
7766 struct perf_mmap_event *mmap_event = data;
7767 struct vm_area_struct *vma = mmap_event->vma;
7768 int executable = vma->vm_flags & VM_EXEC;
7770 return (!executable && event->attr.mmap_data) ||
7771 (executable && (event->attr.mmap || event->attr.mmap2));
7774 static void perf_event_mmap_output(struct perf_event *event,
7777 struct perf_mmap_event *mmap_event = data;
7778 struct perf_output_handle handle;
7779 struct perf_sample_data sample;
7780 int size = mmap_event->event_id.header.size;
7781 u32 type = mmap_event->event_id.header.type;
7784 if (!perf_event_mmap_match(event, data))
7787 if (event->attr.mmap2) {
7788 mmap_event->event_id.header.type = PERF_RECORD_MMAP2;
7789 mmap_event->event_id.header.size += sizeof(mmap_event->maj);
7790 mmap_event->event_id.header.size += sizeof(mmap_event->min);
7791 mmap_event->event_id.header.size += sizeof(mmap_event->ino);
7792 mmap_event->event_id.header.size += sizeof(mmap_event->ino_generation);
7793 mmap_event->event_id.header.size += sizeof(mmap_event->prot);
7794 mmap_event->event_id.header.size += sizeof(mmap_event->flags);
7797 perf_event_header__init_id(&mmap_event->event_id.header, &sample, event);
7798 ret = perf_output_begin(&handle, event,
7799 mmap_event->event_id.header.size);
7803 mmap_event->event_id.pid = perf_event_pid(event, current);
7804 mmap_event->event_id.tid = perf_event_tid(event, current);
7806 perf_output_put(&handle, mmap_event->event_id);
7808 if (event->attr.mmap2) {
7809 perf_output_put(&handle, mmap_event->maj);
7810 perf_output_put(&handle, mmap_event->min);
7811 perf_output_put(&handle, mmap_event->ino);
7812 perf_output_put(&handle, mmap_event->ino_generation);
7813 perf_output_put(&handle, mmap_event->prot);
7814 perf_output_put(&handle, mmap_event->flags);
7817 __output_copy(&handle, mmap_event->file_name,
7818 mmap_event->file_size);
7820 perf_event__output_id_sample(event, &handle, &sample);
7822 perf_output_end(&handle);
7824 mmap_event->event_id.header.size = size;
7825 mmap_event->event_id.header.type = type;
7828 static void perf_event_mmap_event(struct perf_mmap_event *mmap_event)
7830 struct vm_area_struct *vma = mmap_event->vma;
7831 struct file *file = vma->vm_file;
7832 int maj = 0, min = 0;
7833 u64 ino = 0, gen = 0;
7834 u32 prot = 0, flags = 0;
7840 if (vma->vm_flags & VM_READ)
7842 if (vma->vm_flags & VM_WRITE)
7844 if (vma->vm_flags & VM_EXEC)
7847 if (vma->vm_flags & VM_MAYSHARE)
7850 flags = MAP_PRIVATE;
7852 if (vma->vm_flags & VM_DENYWRITE)
7853 flags |= MAP_DENYWRITE;
7854 if (vma->vm_flags & VM_MAYEXEC)
7855 flags |= MAP_EXECUTABLE;
7856 if (vma->vm_flags & VM_LOCKED)
7857 flags |= MAP_LOCKED;
7858 if (vma->vm_flags & VM_HUGETLB)
7859 flags |= MAP_HUGETLB;
7862 struct inode *inode;
7865 buf = kmalloc(PATH_MAX, GFP_KERNEL);
7871 * d_path() works from the end of the rb backwards, so we
7872 * need to add enough zero bytes after the string to handle
7873 * the 64bit alignment we do later.
7875 name = file_path(file, buf, PATH_MAX - sizeof(u64));
7880 inode = file_inode(vma->vm_file);
7881 dev = inode->i_sb->s_dev;
7883 gen = inode->i_generation;
7889 if (vma->vm_ops && vma->vm_ops->name) {
7890 name = (char *) vma->vm_ops->name(vma);
7895 name = (char *)arch_vma_name(vma);
7899 if (vma->vm_start <= vma->vm_mm->start_brk &&
7900 vma->vm_end >= vma->vm_mm->brk) {
7904 if (vma->vm_start <= vma->vm_mm->start_stack &&
7905 vma->vm_end >= vma->vm_mm->start_stack) {
7915 strlcpy(tmp, name, sizeof(tmp));
7919 * Since our buffer works in 8 byte units we need to align our string
7920 * size to a multiple of 8. However, we must guarantee the tail end is
7921 * zero'd out to avoid leaking random bits to userspace.
7923 size = strlen(name)+1;
7924 while (!IS_ALIGNED(size, sizeof(u64)))
7925 name[size++] = '\0';
7927 mmap_event->file_name = name;
7928 mmap_event->file_size = size;
7929 mmap_event->maj = maj;
7930 mmap_event->min = min;
7931 mmap_event->ino = ino;
7932 mmap_event->ino_generation = gen;
7933 mmap_event->prot = prot;
7934 mmap_event->flags = flags;
7936 if (!(vma->vm_flags & VM_EXEC))
7937 mmap_event->event_id.header.misc |= PERF_RECORD_MISC_MMAP_DATA;
7939 mmap_event->event_id.header.size = sizeof(mmap_event->event_id) + size;
7941 perf_iterate_sb(perf_event_mmap_output,
7949 * Check whether inode and address range match filter criteria.
7951 static bool perf_addr_filter_match(struct perf_addr_filter *filter,
7952 struct file *file, unsigned long offset,
7955 /* d_inode(NULL) won't be equal to any mapped user-space file */
7956 if (!filter->path.dentry)
7959 if (d_inode(filter->path.dentry) != file_inode(file))
7962 if (filter->offset > offset + size)
7965 if (filter->offset + filter->size < offset)
7971 static bool perf_addr_filter_vma_adjust(struct perf_addr_filter *filter,
7972 struct vm_area_struct *vma,
7973 struct perf_addr_filter_range *fr)
7975 unsigned long vma_size = vma->vm_end - vma->vm_start;
7976 unsigned long off = vma->vm_pgoff << PAGE_SHIFT;
7977 struct file *file = vma->vm_file;
7979 if (!perf_addr_filter_match(filter, file, off, vma_size))
7982 if (filter->offset < off) {
7983 fr->start = vma->vm_start;
7984 fr->size = min(vma_size, filter->size - (off - filter->offset));
7986 fr->start = vma->vm_start + filter->offset - off;
7987 fr->size = min(vma->vm_end - fr->start, filter->size);
7993 static void __perf_addr_filters_adjust(struct perf_event *event, void *data)
7995 struct perf_addr_filters_head *ifh = perf_event_addr_filters(event);
7996 struct vm_area_struct *vma = data;
7997 struct perf_addr_filter *filter;
7998 unsigned int restart = 0, count = 0;
7999 unsigned long flags;
8001 if (!has_addr_filter(event))
8007 raw_spin_lock_irqsave(&ifh->lock, flags);
8008 list_for_each_entry(filter, &ifh->list, entry) {
8009 if (perf_addr_filter_vma_adjust(filter, vma,
8010 &event->addr_filter_ranges[count]))
8017 event->addr_filters_gen++;
8018 raw_spin_unlock_irqrestore(&ifh->lock, flags);
8021 perf_event_stop(event, 1);
8025 * Adjust all task's events' filters to the new vma
8027 static void perf_addr_filters_adjust(struct vm_area_struct *vma)
8029 struct perf_event_context *ctx;
8033 * Data tracing isn't supported yet and as such there is no need
8034 * to keep track of anything that isn't related to executable code:
8036 if (!(vma->vm_flags & VM_EXEC))
8040 for_each_task_context_nr(ctxn) {
8041 ctx = rcu_dereference(current->perf_event_ctxp[ctxn]);
8045 perf_iterate_ctx(ctx, __perf_addr_filters_adjust, vma, true);
8050 void perf_event_mmap(struct vm_area_struct *vma)
8052 struct perf_mmap_event mmap_event;
8054 if (!atomic_read(&nr_mmap_events))
8057 mmap_event = (struct perf_mmap_event){
8063 .type = PERF_RECORD_MMAP,
8064 .misc = PERF_RECORD_MISC_USER,
8069 .start = vma->vm_start,
8070 .len = vma->vm_end - vma->vm_start,
8071 .pgoff = (u64)vma->vm_pgoff << PAGE_SHIFT,
8073 /* .maj (attr_mmap2 only) */
8074 /* .min (attr_mmap2 only) */
8075 /* .ino (attr_mmap2 only) */
8076 /* .ino_generation (attr_mmap2 only) */
8077 /* .prot (attr_mmap2 only) */
8078 /* .flags (attr_mmap2 only) */
8081 perf_addr_filters_adjust(vma);
8082 perf_event_mmap_event(&mmap_event);
8085 void perf_event_aux_event(struct perf_event *event, unsigned long head,
8086 unsigned long size, u64 flags)
8088 struct perf_output_handle handle;
8089 struct perf_sample_data sample;
8090 struct perf_aux_event {
8091 struct perf_event_header header;
8097 .type = PERF_RECORD_AUX,
8099 .size = sizeof(rec),
8107 perf_event_header__init_id(&rec.header, &sample, event);
8108 ret = perf_output_begin(&handle, event, rec.header.size);
8113 perf_output_put(&handle, rec);
8114 perf_event__output_id_sample(event, &handle, &sample);
8116 perf_output_end(&handle);
8120 * Lost/dropped samples logging
8122 void perf_log_lost_samples(struct perf_event *event, u64 lost)
8124 struct perf_output_handle handle;
8125 struct perf_sample_data sample;
8129 struct perf_event_header header;
8131 } lost_samples_event = {
8133 .type = PERF_RECORD_LOST_SAMPLES,
8135 .size = sizeof(lost_samples_event),
8140 perf_event_header__init_id(&lost_samples_event.header, &sample, event);
8142 ret = perf_output_begin(&handle, event,
8143 lost_samples_event.header.size);
8147 perf_output_put(&handle, lost_samples_event);
8148 perf_event__output_id_sample(event, &handle, &sample);
8149 perf_output_end(&handle);
8153 * context_switch tracking
8156 struct perf_switch_event {
8157 struct task_struct *task;
8158 struct task_struct *next_prev;
8161 struct perf_event_header header;
8167 static int perf_event_switch_match(struct perf_event *event)
8169 return event->attr.context_switch;
8172 static void perf_event_switch_output(struct perf_event *event, void *data)
8174 struct perf_switch_event *se = data;
8175 struct perf_output_handle handle;
8176 struct perf_sample_data sample;
8179 if (!perf_event_switch_match(event))
8182 /* Only CPU-wide events are allowed to see next/prev pid/tid */
8183 if (event->ctx->task) {
8184 se->event_id.header.type = PERF_RECORD_SWITCH;
8185 se->event_id.header.size = sizeof(se->event_id.header);
8187 se->event_id.header.type = PERF_RECORD_SWITCH_CPU_WIDE;
8188 se->event_id.header.size = sizeof(se->event_id);
8189 se->event_id.next_prev_pid =
8190 perf_event_pid(event, se->next_prev);
8191 se->event_id.next_prev_tid =
8192 perf_event_tid(event, se->next_prev);
8195 perf_event_header__init_id(&se->event_id.header, &sample, event);
8197 ret = perf_output_begin(&handle, event, se->event_id.header.size);
8201 if (event->ctx->task)
8202 perf_output_put(&handle, se->event_id.header);
8204 perf_output_put(&handle, se->event_id);
8206 perf_event__output_id_sample(event, &handle, &sample);
8208 perf_output_end(&handle);
8211 static void perf_event_switch(struct task_struct *task,
8212 struct task_struct *next_prev, bool sched_in)
8214 struct perf_switch_event switch_event;
8216 /* N.B. caller checks nr_switch_events != 0 */
8218 switch_event = (struct perf_switch_event){
8220 .next_prev = next_prev,
8224 .misc = sched_in ? 0 : PERF_RECORD_MISC_SWITCH_OUT,
8227 /* .next_prev_pid */
8228 /* .next_prev_tid */
8232 if (!sched_in && task->state == TASK_RUNNING)
8233 switch_event.event_id.header.misc |=
8234 PERF_RECORD_MISC_SWITCH_OUT_PREEMPT;
8236 perf_iterate_sb(perf_event_switch_output,
8242 * IRQ throttle logging
8245 static void perf_log_throttle(struct perf_event *event, int enable)
8247 struct perf_output_handle handle;
8248 struct perf_sample_data sample;
8252 struct perf_event_header header;
8256 } throttle_event = {
8258 .type = PERF_RECORD_THROTTLE,
8260 .size = sizeof(throttle_event),
8262 .time = perf_event_clock(event),
8263 .id = primary_event_id(event),
8264 .stream_id = event->id,
8268 throttle_event.header.type = PERF_RECORD_UNTHROTTLE;
8270 perf_event_header__init_id(&throttle_event.header, &sample, event);
8272 ret = perf_output_begin(&handle, event,
8273 throttle_event.header.size);
8277 perf_output_put(&handle, throttle_event);
8278 perf_event__output_id_sample(event, &handle, &sample);
8279 perf_output_end(&handle);
8283 * ksymbol register/unregister tracking
8286 struct perf_ksymbol_event {
8290 struct perf_event_header header;
8298 static int perf_event_ksymbol_match(struct perf_event *event)
8300 return event->attr.ksymbol;
8303 static void perf_event_ksymbol_output(struct perf_event *event, void *data)
8305 struct perf_ksymbol_event *ksymbol_event = data;
8306 struct perf_output_handle handle;
8307 struct perf_sample_data sample;
8310 if (!perf_event_ksymbol_match(event))
8313 perf_event_header__init_id(&ksymbol_event->event_id.header,
8315 ret = perf_output_begin(&handle, event,
8316 ksymbol_event->event_id.header.size);
8320 perf_output_put(&handle, ksymbol_event->event_id);
8321 __output_copy(&handle, ksymbol_event->name, ksymbol_event->name_len);
8322 perf_event__output_id_sample(event, &handle, &sample);
8324 perf_output_end(&handle);
8327 void perf_event_ksymbol(u16 ksym_type, u64 addr, u32 len, bool unregister,
8330 struct perf_ksymbol_event ksymbol_event;
8331 char name[KSYM_NAME_LEN];
8335 if (!atomic_read(&nr_ksymbol_events))
8338 if (ksym_type >= PERF_RECORD_KSYMBOL_TYPE_MAX ||
8339 ksym_type == PERF_RECORD_KSYMBOL_TYPE_UNKNOWN)
8342 strlcpy(name, sym, KSYM_NAME_LEN);
8343 name_len = strlen(name) + 1;
8344 while (!IS_ALIGNED(name_len, sizeof(u64)))
8345 name[name_len++] = '\0';
8346 BUILD_BUG_ON(KSYM_NAME_LEN % sizeof(u64));
8349 flags |= PERF_RECORD_KSYMBOL_FLAGS_UNREGISTER;
8351 ksymbol_event = (struct perf_ksymbol_event){
8353 .name_len = name_len,
8356 .type = PERF_RECORD_KSYMBOL,
8357 .size = sizeof(ksymbol_event.event_id) +
8362 .ksym_type = ksym_type,
8367 perf_iterate_sb(perf_event_ksymbol_output, &ksymbol_event, NULL);
8370 WARN_ONCE(1, "%s: Invalid KSYMBOL type 0x%x\n", __func__, ksym_type);
8374 * bpf program load/unload tracking
8377 struct perf_bpf_event {
8378 struct bpf_prog *prog;
8380 struct perf_event_header header;
8384 u8 tag[BPF_TAG_SIZE];
8388 static int perf_event_bpf_match(struct perf_event *event)
8390 return event->attr.bpf_event;
8393 static void perf_event_bpf_output(struct perf_event *event, void *data)
8395 struct perf_bpf_event *bpf_event = data;
8396 struct perf_output_handle handle;
8397 struct perf_sample_data sample;
8400 if (!perf_event_bpf_match(event))
8403 perf_event_header__init_id(&bpf_event->event_id.header,
8405 ret = perf_output_begin(&handle, event,
8406 bpf_event->event_id.header.size);
8410 perf_output_put(&handle, bpf_event->event_id);
8411 perf_event__output_id_sample(event, &handle, &sample);
8413 perf_output_end(&handle);
8416 static void perf_event_bpf_emit_ksymbols(struct bpf_prog *prog,
8417 enum perf_bpf_event_type type)
8419 bool unregister = type == PERF_BPF_EVENT_PROG_UNLOAD;
8422 if (prog->aux->func_cnt == 0) {
8423 perf_event_ksymbol(PERF_RECORD_KSYMBOL_TYPE_BPF,
8424 (u64)(unsigned long)prog->bpf_func,
8425 prog->jited_len, unregister,
8426 prog->aux->ksym.name);
8428 for (i = 0; i < prog->aux->func_cnt; i++) {
8429 struct bpf_prog *subprog = prog->aux->func[i];
8432 PERF_RECORD_KSYMBOL_TYPE_BPF,
8433 (u64)(unsigned long)subprog->bpf_func,
8434 subprog->jited_len, unregister,
8435 prog->aux->ksym.name);
8440 void perf_event_bpf_event(struct bpf_prog *prog,
8441 enum perf_bpf_event_type type,
8444 struct perf_bpf_event bpf_event;
8446 if (type <= PERF_BPF_EVENT_UNKNOWN ||
8447 type >= PERF_BPF_EVENT_MAX)
8451 case PERF_BPF_EVENT_PROG_LOAD:
8452 case PERF_BPF_EVENT_PROG_UNLOAD:
8453 if (atomic_read(&nr_ksymbol_events))
8454 perf_event_bpf_emit_ksymbols(prog, type);
8460 if (!atomic_read(&nr_bpf_events))
8463 bpf_event = (struct perf_bpf_event){
8467 .type = PERF_RECORD_BPF_EVENT,
8468 .size = sizeof(bpf_event.event_id),
8472 .id = prog->aux->id,
8476 BUILD_BUG_ON(BPF_TAG_SIZE % sizeof(u64));
8478 memcpy(bpf_event.event_id.tag, prog->tag, BPF_TAG_SIZE);
8479 perf_iterate_sb(perf_event_bpf_output, &bpf_event, NULL);
8482 void perf_event_itrace_started(struct perf_event *event)
8484 event->attach_state |= PERF_ATTACH_ITRACE;
8487 static void perf_log_itrace_start(struct perf_event *event)
8489 struct perf_output_handle handle;
8490 struct perf_sample_data sample;
8491 struct perf_aux_event {
8492 struct perf_event_header header;
8499 event = event->parent;
8501 if (!(event->pmu->capabilities & PERF_PMU_CAP_ITRACE) ||
8502 event->attach_state & PERF_ATTACH_ITRACE)
8505 rec.header.type = PERF_RECORD_ITRACE_START;
8506 rec.header.misc = 0;
8507 rec.header.size = sizeof(rec);
8508 rec.pid = perf_event_pid(event, current);
8509 rec.tid = perf_event_tid(event, current);
8511 perf_event_header__init_id(&rec.header, &sample, event);
8512 ret = perf_output_begin(&handle, event, rec.header.size);
8517 perf_output_put(&handle, rec);
8518 perf_event__output_id_sample(event, &handle, &sample);
8520 perf_output_end(&handle);
8524 __perf_event_account_interrupt(struct perf_event *event, int throttle)
8526 struct hw_perf_event *hwc = &event->hw;
8530 seq = __this_cpu_read(perf_throttled_seq);
8531 if (seq != hwc->interrupts_seq) {
8532 hwc->interrupts_seq = seq;
8533 hwc->interrupts = 1;
8536 if (unlikely(throttle
8537 && hwc->interrupts >= max_samples_per_tick)) {
8538 __this_cpu_inc(perf_throttled_count);
8539 tick_dep_set_cpu(smp_processor_id(), TICK_DEP_BIT_PERF_EVENTS);
8540 hwc->interrupts = MAX_INTERRUPTS;
8541 perf_log_throttle(event, 0);
8546 if (event->attr.freq) {
8547 u64 now = perf_clock();
8548 s64 delta = now - hwc->freq_time_stamp;
8550 hwc->freq_time_stamp = now;
8552 if (delta > 0 && delta < 2*TICK_NSEC)
8553 perf_adjust_period(event, delta, hwc->last_period, true);
8559 int perf_event_account_interrupt(struct perf_event *event)
8561 return __perf_event_account_interrupt(event, 1);
8565 * Generic event overflow handling, sampling.
8568 static int __perf_event_overflow(struct perf_event *event,
8569 int throttle, struct perf_sample_data *data,
8570 struct pt_regs *regs)
8572 int events = atomic_read(&event->event_limit);
8576 * Non-sampling counters might still use the PMI to fold short
8577 * hardware counters, ignore those.
8579 if (unlikely(!is_sampling_event(event)))
8582 ret = __perf_event_account_interrupt(event, throttle);
8585 * XXX event_limit might not quite work as expected on inherited
8589 event->pending_kill = POLL_IN;
8590 if (events && atomic_dec_and_test(&event->event_limit)) {
8592 event->pending_kill = POLL_HUP;
8594 perf_event_disable_inatomic(event);
8597 READ_ONCE(event->overflow_handler)(event, data, regs);
8599 if (*perf_event_fasync(event) && event->pending_kill) {
8600 event->pending_wakeup = 1;
8601 irq_work_queue(&event->pending);
8607 int perf_event_overflow(struct perf_event *event,
8608 struct perf_sample_data *data,
8609 struct pt_regs *regs)
8611 return __perf_event_overflow(event, 1, data, regs);
8615 * Generic software event infrastructure
8618 struct swevent_htable {
8619 struct swevent_hlist *swevent_hlist;
8620 struct mutex hlist_mutex;
8623 /* Recursion avoidance in each contexts */
8624 int recursion[PERF_NR_CONTEXTS];
8627 static DEFINE_PER_CPU(struct swevent_htable, swevent_htable);
8630 * We directly increment event->count and keep a second value in
8631 * event->hw.period_left to count intervals. This period event
8632 * is kept in the range [-sample_period, 0] so that we can use the
8636 u64 perf_swevent_set_period(struct perf_event *event)
8638 struct hw_perf_event *hwc = &event->hw;
8639 u64 period = hwc->last_period;
8643 hwc->last_period = hwc->sample_period;
8646 old = val = local64_read(&hwc->period_left);
8650 nr = div64_u64(period + val, period);
8651 offset = nr * period;
8653 if (local64_cmpxchg(&hwc->period_left, old, val) != old)
8659 static void perf_swevent_overflow(struct perf_event *event, u64 overflow,
8660 struct perf_sample_data *data,
8661 struct pt_regs *regs)
8663 struct hw_perf_event *hwc = &event->hw;
8667 overflow = perf_swevent_set_period(event);
8669 if (hwc->interrupts == MAX_INTERRUPTS)
8672 for (; overflow; overflow--) {
8673 if (__perf_event_overflow(event, throttle,
8676 * We inhibit the overflow from happening when
8677 * hwc->interrupts == MAX_INTERRUPTS.
8685 static void perf_swevent_event(struct perf_event *event, u64 nr,
8686 struct perf_sample_data *data,
8687 struct pt_regs *regs)
8689 struct hw_perf_event *hwc = &event->hw;
8691 local64_add(nr, &event->count);
8696 if (!is_sampling_event(event))
8699 if ((event->attr.sample_type & PERF_SAMPLE_PERIOD) && !event->attr.freq) {
8701 return perf_swevent_overflow(event, 1, data, regs);
8703 data->period = event->hw.last_period;
8705 if (nr == 1 && hwc->sample_period == 1 && !event->attr.freq)
8706 return perf_swevent_overflow(event, 1, data, regs);
8708 if (local64_add_negative(nr, &hwc->period_left))
8711 perf_swevent_overflow(event, 0, data, regs);
8714 static int perf_exclude_event(struct perf_event *event,
8715 struct pt_regs *regs)
8717 if (event->hw.state & PERF_HES_STOPPED)
8721 if (event->attr.exclude_user && user_mode(regs))
8724 if (event->attr.exclude_kernel && !user_mode(regs))
8731 static int perf_swevent_match(struct perf_event *event,
8732 enum perf_type_id type,
8734 struct perf_sample_data *data,
8735 struct pt_regs *regs)
8737 if (event->attr.type != type)
8740 if (event->attr.config != event_id)
8743 if (perf_exclude_event(event, regs))
8749 static inline u64 swevent_hash(u64 type, u32 event_id)
8751 u64 val = event_id | (type << 32);
8753 return hash_64(val, SWEVENT_HLIST_BITS);
8756 static inline struct hlist_head *
8757 __find_swevent_head(struct swevent_hlist *hlist, u64 type, u32 event_id)
8759 u64 hash = swevent_hash(type, event_id);
8761 return &hlist->heads[hash];
8764 /* For the read side: events when they trigger */
8765 static inline struct hlist_head *
8766 find_swevent_head_rcu(struct swevent_htable *swhash, u64 type, u32 event_id)
8768 struct swevent_hlist *hlist;
8770 hlist = rcu_dereference(swhash->swevent_hlist);
8774 return __find_swevent_head(hlist, type, event_id);
8777 /* For the event head insertion and removal in the hlist */
8778 static inline struct hlist_head *
8779 find_swevent_head(struct swevent_htable *swhash, struct perf_event *event)
8781 struct swevent_hlist *hlist;
8782 u32 event_id = event->attr.config;
8783 u64 type = event->attr.type;
8786 * Event scheduling is always serialized against hlist allocation
8787 * and release. Which makes the protected version suitable here.
8788 * The context lock guarantees that.
8790 hlist = rcu_dereference_protected(swhash->swevent_hlist,
8791 lockdep_is_held(&event->ctx->lock));
8795 return __find_swevent_head(hlist, type, event_id);
8798 static void do_perf_sw_event(enum perf_type_id type, u32 event_id,
8800 struct perf_sample_data *data,
8801 struct pt_regs *regs)
8803 struct swevent_htable *swhash = this_cpu_ptr(&swevent_htable);
8804 struct perf_event *event;
8805 struct hlist_head *head;
8808 head = find_swevent_head_rcu(swhash, type, event_id);
8812 hlist_for_each_entry_rcu(event, head, hlist_entry) {
8813 if (perf_swevent_match(event, type, event_id, data, regs))
8814 perf_swevent_event(event, nr, data, regs);
8820 DEFINE_PER_CPU(struct pt_regs, __perf_regs[4]);
8822 int perf_swevent_get_recursion_context(void)
8824 struct swevent_htable *swhash = this_cpu_ptr(&swevent_htable);
8826 return get_recursion_context(swhash->recursion);
8828 EXPORT_SYMBOL_GPL(perf_swevent_get_recursion_context);
8830 void perf_swevent_put_recursion_context(int rctx)
8832 struct swevent_htable *swhash = this_cpu_ptr(&swevent_htable);
8834 put_recursion_context(swhash->recursion, rctx);
8837 void ___perf_sw_event(u32 event_id, u64 nr, struct pt_regs *regs, u64 addr)
8839 struct perf_sample_data data;
8841 if (WARN_ON_ONCE(!regs))
8844 perf_sample_data_init(&data, addr, 0);
8845 do_perf_sw_event(PERF_TYPE_SOFTWARE, event_id, nr, &data, regs);
8848 void __perf_sw_event(u32 event_id, u64 nr, struct pt_regs *regs, u64 addr)
8852 preempt_disable_notrace();
8853 rctx = perf_swevent_get_recursion_context();
8854 if (unlikely(rctx < 0))
8857 ___perf_sw_event(event_id, nr, regs, addr);
8859 perf_swevent_put_recursion_context(rctx);
8861 preempt_enable_notrace();
8864 static void perf_swevent_read(struct perf_event *event)
8868 static int perf_swevent_add(struct perf_event *event, int flags)
8870 struct swevent_htable *swhash = this_cpu_ptr(&swevent_htable);
8871 struct hw_perf_event *hwc = &event->hw;
8872 struct hlist_head *head;
8874 if (is_sampling_event(event)) {
8875 hwc->last_period = hwc->sample_period;
8876 perf_swevent_set_period(event);
8879 hwc->state = !(flags & PERF_EF_START);
8881 head = find_swevent_head(swhash, event);
8882 if (WARN_ON_ONCE(!head))
8885 hlist_add_head_rcu(&event->hlist_entry, head);
8886 perf_event_update_userpage(event);
8891 static void perf_swevent_del(struct perf_event *event, int flags)
8893 hlist_del_rcu(&event->hlist_entry);
8896 static void perf_swevent_start(struct perf_event *event, int flags)
8898 event->hw.state = 0;
8901 static void perf_swevent_stop(struct perf_event *event, int flags)
8903 event->hw.state = PERF_HES_STOPPED;
8906 /* Deref the hlist from the update side */
8907 static inline struct swevent_hlist *
8908 swevent_hlist_deref(struct swevent_htable *swhash)
8910 return rcu_dereference_protected(swhash->swevent_hlist,
8911 lockdep_is_held(&swhash->hlist_mutex));
8914 static void swevent_hlist_release(struct swevent_htable *swhash)
8916 struct swevent_hlist *hlist = swevent_hlist_deref(swhash);
8921 RCU_INIT_POINTER(swhash->swevent_hlist, NULL);
8922 kfree_rcu(hlist, rcu_head);
8925 static void swevent_hlist_put_cpu(int cpu)
8927 struct swevent_htable *swhash = &per_cpu(swevent_htable, cpu);
8929 mutex_lock(&swhash->hlist_mutex);
8931 if (!--swhash->hlist_refcount)
8932 swevent_hlist_release(swhash);
8934 mutex_unlock(&swhash->hlist_mutex);
8937 static void swevent_hlist_put(void)
8941 for_each_possible_cpu(cpu)
8942 swevent_hlist_put_cpu(cpu);
8945 static int swevent_hlist_get_cpu(int cpu)
8947 struct swevent_htable *swhash = &per_cpu(swevent_htable, cpu);
8950 mutex_lock(&swhash->hlist_mutex);
8951 if (!swevent_hlist_deref(swhash) &&
8952 cpumask_test_cpu(cpu, perf_online_mask)) {
8953 struct swevent_hlist *hlist;
8955 hlist = kzalloc(sizeof(*hlist), GFP_KERNEL);
8960 rcu_assign_pointer(swhash->swevent_hlist, hlist);
8962 swhash->hlist_refcount++;
8964 mutex_unlock(&swhash->hlist_mutex);
8969 static int swevent_hlist_get(void)
8971 int err, cpu, failed_cpu;
8973 mutex_lock(&pmus_lock);
8974 for_each_possible_cpu(cpu) {
8975 err = swevent_hlist_get_cpu(cpu);
8981 mutex_unlock(&pmus_lock);
8984 for_each_possible_cpu(cpu) {
8985 if (cpu == failed_cpu)
8987 swevent_hlist_put_cpu(cpu);
8989 mutex_unlock(&pmus_lock);
8993 struct static_key perf_swevent_enabled[PERF_COUNT_SW_MAX];
8995 static void sw_perf_event_destroy(struct perf_event *event)
8997 u64 event_id = event->attr.config;
8999 WARN_ON(event->parent);
9001 static_key_slow_dec(&perf_swevent_enabled[event_id]);
9002 swevent_hlist_put();
9005 static int perf_swevent_init(struct perf_event *event)
9007 u64 event_id = event->attr.config;
9009 if (event->attr.type != PERF_TYPE_SOFTWARE)
9013 * no branch sampling for software events
9015 if (has_branch_stack(event))
9019 case PERF_COUNT_SW_CPU_CLOCK:
9020 case PERF_COUNT_SW_TASK_CLOCK:
9027 if (event_id >= PERF_COUNT_SW_MAX)
9030 if (!event->parent) {
9033 err = swevent_hlist_get();
9037 static_key_slow_inc(&perf_swevent_enabled[event_id]);
9038 event->destroy = sw_perf_event_destroy;
9044 static struct pmu perf_swevent = {
9045 .task_ctx_nr = perf_sw_context,
9047 .capabilities = PERF_PMU_CAP_NO_NMI,
9049 .event_init = perf_swevent_init,
9050 .add = perf_swevent_add,
9051 .del = perf_swevent_del,
9052 .start = perf_swevent_start,
9053 .stop = perf_swevent_stop,
9054 .read = perf_swevent_read,
9057 #ifdef CONFIG_EVENT_TRACING
9059 static int perf_tp_filter_match(struct perf_event *event,
9060 struct perf_sample_data *data)
9062 void *record = data->raw->frag.data;
9064 /* only top level events have filters set */
9066 event = event->parent;
9068 if (likely(!event->filter) || filter_match_preds(event->filter, record))
9073 static int perf_tp_event_match(struct perf_event *event,
9074 struct perf_sample_data *data,
9075 struct pt_regs *regs)
9077 if (event->hw.state & PERF_HES_STOPPED)
9080 * If exclude_kernel, only trace user-space tracepoints (uprobes)
9082 if (event->attr.exclude_kernel && !user_mode(regs))
9085 if (!perf_tp_filter_match(event, data))
9091 void perf_trace_run_bpf_submit(void *raw_data, int size, int rctx,
9092 struct trace_event_call *call, u64 count,
9093 struct pt_regs *regs, struct hlist_head *head,
9094 struct task_struct *task)
9096 if (bpf_prog_array_valid(call)) {
9097 *(struct pt_regs **)raw_data = regs;
9098 if (!trace_call_bpf(call, raw_data) || hlist_empty(head)) {
9099 perf_swevent_put_recursion_context(rctx);
9103 perf_tp_event(call->event.type, count, raw_data, size, regs, head,
9106 EXPORT_SYMBOL_GPL(perf_trace_run_bpf_submit);
9108 void perf_tp_event(u16 event_type, u64 count, void *record, int entry_size,
9109 struct pt_regs *regs, struct hlist_head *head, int rctx,
9110 struct task_struct *task)
9112 struct perf_sample_data data;
9113 struct perf_event *event;
9115 struct perf_raw_record raw = {
9122 perf_sample_data_init(&data, 0, 0);
9125 perf_trace_buf_update(record, event_type);
9127 hlist_for_each_entry_rcu(event, head, hlist_entry) {
9128 if (perf_tp_event_match(event, &data, regs))
9129 perf_swevent_event(event, count, &data, regs);
9133 * If we got specified a target task, also iterate its context and
9134 * deliver this event there too.
9136 if (task && task != current) {
9137 struct perf_event_context *ctx;
9138 struct trace_entry *entry = record;
9141 ctx = rcu_dereference(task->perf_event_ctxp[perf_sw_context]);
9145 list_for_each_entry_rcu(event, &ctx->event_list, event_entry) {
9146 if (event->cpu != smp_processor_id())
9148 if (event->attr.type != PERF_TYPE_TRACEPOINT)
9150 if (event->attr.config != entry->type)
9152 if (perf_tp_event_match(event, &data, regs))
9153 perf_swevent_event(event, count, &data, regs);
9159 perf_swevent_put_recursion_context(rctx);
9161 EXPORT_SYMBOL_GPL(perf_tp_event);
9163 static void tp_perf_event_destroy(struct perf_event *event)
9165 perf_trace_destroy(event);
9168 static int perf_tp_event_init(struct perf_event *event)
9172 if (event->attr.type != PERF_TYPE_TRACEPOINT)
9176 * no branch sampling for tracepoint events
9178 if (has_branch_stack(event))
9181 err = perf_trace_init(event);
9185 event->destroy = tp_perf_event_destroy;
9190 static struct pmu perf_tracepoint = {
9191 .task_ctx_nr = perf_sw_context,
9193 .event_init = perf_tp_event_init,
9194 .add = perf_trace_add,
9195 .del = perf_trace_del,
9196 .start = perf_swevent_start,
9197 .stop = perf_swevent_stop,
9198 .read = perf_swevent_read,
9201 #if defined(CONFIG_KPROBE_EVENTS) || defined(CONFIG_UPROBE_EVENTS)
9203 * Flags in config, used by dynamic PMU kprobe and uprobe
9204 * The flags should match following PMU_FORMAT_ATTR().
9206 * PERF_PROBE_CONFIG_IS_RETPROBE if set, create kretprobe/uretprobe
9207 * if not set, create kprobe/uprobe
9209 * The following values specify a reference counter (or semaphore in the
9210 * terminology of tools like dtrace, systemtap, etc.) Userspace Statically
9211 * Defined Tracepoints (USDT). Currently, we use 40 bit for the offset.
9213 * PERF_UPROBE_REF_CTR_OFFSET_BITS # of bits in config as th offset
9214 * PERF_UPROBE_REF_CTR_OFFSET_SHIFT # of bits to shift left
9216 enum perf_probe_config {
9217 PERF_PROBE_CONFIG_IS_RETPROBE = 1U << 0, /* [k,u]retprobe */
9218 PERF_UPROBE_REF_CTR_OFFSET_BITS = 32,
9219 PERF_UPROBE_REF_CTR_OFFSET_SHIFT = 64 - PERF_UPROBE_REF_CTR_OFFSET_BITS,
9222 PMU_FORMAT_ATTR(retprobe, "config:0");
9225 #ifdef CONFIG_KPROBE_EVENTS
9226 static struct attribute *kprobe_attrs[] = {
9227 &format_attr_retprobe.attr,
9231 static struct attribute_group kprobe_format_group = {
9233 .attrs = kprobe_attrs,
9236 static const struct attribute_group *kprobe_attr_groups[] = {
9237 &kprobe_format_group,
9241 static int perf_kprobe_event_init(struct perf_event *event);
9242 static struct pmu perf_kprobe = {
9243 .task_ctx_nr = perf_sw_context,
9244 .event_init = perf_kprobe_event_init,
9245 .add = perf_trace_add,
9246 .del = perf_trace_del,
9247 .start = perf_swevent_start,
9248 .stop = perf_swevent_stop,
9249 .read = perf_swevent_read,
9250 .attr_groups = kprobe_attr_groups,
9253 static int perf_kprobe_event_init(struct perf_event *event)
9258 if (event->attr.type != perf_kprobe.type)
9261 if (!capable(CAP_SYS_ADMIN))
9265 * no branch sampling for probe events
9267 if (has_branch_stack(event))
9270 is_retprobe = event->attr.config & PERF_PROBE_CONFIG_IS_RETPROBE;
9271 err = perf_kprobe_init(event, is_retprobe);
9275 event->destroy = perf_kprobe_destroy;
9279 #endif /* CONFIG_KPROBE_EVENTS */
9281 #ifdef CONFIG_UPROBE_EVENTS
9282 PMU_FORMAT_ATTR(ref_ctr_offset, "config:32-63");
9284 static struct attribute *uprobe_attrs[] = {
9285 &format_attr_retprobe.attr,
9286 &format_attr_ref_ctr_offset.attr,
9290 static struct attribute_group uprobe_format_group = {
9292 .attrs = uprobe_attrs,
9295 static const struct attribute_group *uprobe_attr_groups[] = {
9296 &uprobe_format_group,
9300 static int perf_uprobe_event_init(struct perf_event *event);
9301 static struct pmu perf_uprobe = {
9302 .task_ctx_nr = perf_sw_context,
9303 .event_init = perf_uprobe_event_init,
9304 .add = perf_trace_add,
9305 .del = perf_trace_del,
9306 .start = perf_swevent_start,
9307 .stop = perf_swevent_stop,
9308 .read = perf_swevent_read,
9309 .attr_groups = uprobe_attr_groups,
9312 static int perf_uprobe_event_init(struct perf_event *event)
9315 unsigned long ref_ctr_offset;
9318 if (event->attr.type != perf_uprobe.type)
9321 if (!capable(CAP_SYS_ADMIN))
9325 * no branch sampling for probe events
9327 if (has_branch_stack(event))
9330 is_retprobe = event->attr.config & PERF_PROBE_CONFIG_IS_RETPROBE;
9331 ref_ctr_offset = event->attr.config >> PERF_UPROBE_REF_CTR_OFFSET_SHIFT;
9332 err = perf_uprobe_init(event, ref_ctr_offset, is_retprobe);
9336 event->destroy = perf_uprobe_destroy;
9340 #endif /* CONFIG_UPROBE_EVENTS */
9342 static inline void perf_tp_register(void)
9344 perf_pmu_register(&perf_tracepoint, "tracepoint", PERF_TYPE_TRACEPOINT);
9345 #ifdef CONFIG_KPROBE_EVENTS
9346 perf_pmu_register(&perf_kprobe, "kprobe", -1);
9348 #ifdef CONFIG_UPROBE_EVENTS
9349 perf_pmu_register(&perf_uprobe, "uprobe", -1);
9353 static void perf_event_free_filter(struct perf_event *event)
9355 ftrace_profile_free_filter(event);
9358 #ifdef CONFIG_BPF_SYSCALL
9359 static void bpf_overflow_handler(struct perf_event *event,
9360 struct perf_sample_data *data,
9361 struct pt_regs *regs)
9363 struct bpf_perf_event_data_kern ctx = {
9369 ctx.regs = perf_arch_bpf_user_pt_regs(regs);
9370 if (unlikely(__this_cpu_inc_return(bpf_prog_active) != 1))
9373 ret = BPF_PROG_RUN(event->prog, &ctx);
9376 __this_cpu_dec(bpf_prog_active);
9380 event->orig_overflow_handler(event, data, regs);
9383 static int perf_event_set_bpf_handler(struct perf_event *event, u32 prog_fd)
9385 struct bpf_prog *prog;
9387 if (event->overflow_handler_context)
9388 /* hw breakpoint or kernel counter */
9394 prog = bpf_prog_get_type(prog_fd, BPF_PROG_TYPE_PERF_EVENT);
9396 return PTR_ERR(prog);
9399 event->orig_overflow_handler = READ_ONCE(event->overflow_handler);
9400 WRITE_ONCE(event->overflow_handler, bpf_overflow_handler);
9404 static void perf_event_free_bpf_handler(struct perf_event *event)
9406 struct bpf_prog *prog = event->prog;
9411 WRITE_ONCE(event->overflow_handler, event->orig_overflow_handler);
9416 static int perf_event_set_bpf_handler(struct perf_event *event, u32 prog_fd)
9420 static void perf_event_free_bpf_handler(struct perf_event *event)
9426 * returns true if the event is a tracepoint, or a kprobe/upprobe created
9427 * with perf_event_open()
9429 static inline bool perf_event_is_tracing(struct perf_event *event)
9431 if (event->pmu == &perf_tracepoint)
9433 #ifdef CONFIG_KPROBE_EVENTS
9434 if (event->pmu == &perf_kprobe)
9437 #ifdef CONFIG_UPROBE_EVENTS
9438 if (event->pmu == &perf_uprobe)
9444 static int perf_event_set_bpf_prog(struct perf_event *event, u32 prog_fd)
9446 bool is_kprobe, is_tracepoint, is_syscall_tp;
9447 struct bpf_prog *prog;
9450 if (!perf_event_is_tracing(event))
9451 return perf_event_set_bpf_handler(event, prog_fd);
9453 is_kprobe = event->tp_event->flags & TRACE_EVENT_FL_UKPROBE;
9454 is_tracepoint = event->tp_event->flags & TRACE_EVENT_FL_TRACEPOINT;
9455 is_syscall_tp = is_syscall_trace_event(event->tp_event);
9456 if (!is_kprobe && !is_tracepoint && !is_syscall_tp)
9457 /* bpf programs can only be attached to u/kprobe or tracepoint */
9460 prog = bpf_prog_get(prog_fd);
9462 return PTR_ERR(prog);
9464 if ((is_kprobe && prog->type != BPF_PROG_TYPE_KPROBE) ||
9465 (is_tracepoint && prog->type != BPF_PROG_TYPE_TRACEPOINT) ||
9466 (is_syscall_tp && prog->type != BPF_PROG_TYPE_TRACEPOINT)) {
9467 /* valid fd, but invalid bpf program type */
9472 /* Kprobe override only works for kprobes, not uprobes. */
9473 if (prog->kprobe_override &&
9474 !(event->tp_event->flags & TRACE_EVENT_FL_KPROBE)) {
9479 if (is_tracepoint || is_syscall_tp) {
9480 int off = trace_event_get_offsets(event->tp_event);
9482 if (prog->aux->max_ctx_offset > off) {
9488 ret = perf_event_attach_bpf_prog(event, prog);
9494 static void perf_event_free_bpf_prog(struct perf_event *event)
9496 if (!perf_event_is_tracing(event)) {
9497 perf_event_free_bpf_handler(event);
9500 perf_event_detach_bpf_prog(event);
9505 static inline void perf_tp_register(void)
9509 static void perf_event_free_filter(struct perf_event *event)
9513 static int perf_event_set_bpf_prog(struct perf_event *event, u32 prog_fd)
9518 static void perf_event_free_bpf_prog(struct perf_event *event)
9521 #endif /* CONFIG_EVENT_TRACING */
9523 #ifdef CONFIG_HAVE_HW_BREAKPOINT
9524 void perf_bp_event(struct perf_event *bp, void *data)
9526 struct perf_sample_data sample;
9527 struct pt_regs *regs = data;
9529 perf_sample_data_init(&sample, bp->attr.bp_addr, 0);
9531 if (!bp->hw.state && !perf_exclude_event(bp, regs))
9532 perf_swevent_event(bp, 1, &sample, regs);
9537 * Allocate a new address filter
9539 static struct perf_addr_filter *
9540 perf_addr_filter_new(struct perf_event *event, struct list_head *filters)
9542 int node = cpu_to_node(event->cpu == -1 ? 0 : event->cpu);
9543 struct perf_addr_filter *filter;
9545 filter = kzalloc_node(sizeof(*filter), GFP_KERNEL, node);
9549 INIT_LIST_HEAD(&filter->entry);
9550 list_add_tail(&filter->entry, filters);
9555 static void free_filters_list(struct list_head *filters)
9557 struct perf_addr_filter *filter, *iter;
9559 list_for_each_entry_safe(filter, iter, filters, entry) {
9560 path_put(&filter->path);
9561 list_del(&filter->entry);
9567 * Free existing address filters and optionally install new ones
9569 static void perf_addr_filters_splice(struct perf_event *event,
9570 struct list_head *head)
9572 unsigned long flags;
9575 if (!has_addr_filter(event))
9578 /* don't bother with children, they don't have their own filters */
9582 raw_spin_lock_irqsave(&event->addr_filters.lock, flags);
9584 list_splice_init(&event->addr_filters.list, &list);
9586 list_splice(head, &event->addr_filters.list);
9588 raw_spin_unlock_irqrestore(&event->addr_filters.lock, flags);
9590 free_filters_list(&list);
9594 * Scan through mm's vmas and see if one of them matches the
9595 * @filter; if so, adjust filter's address range.
9596 * Called with mm::mmap_sem down for reading.
9598 static void perf_addr_filter_apply(struct perf_addr_filter *filter,
9599 struct mm_struct *mm,
9600 struct perf_addr_filter_range *fr)
9602 struct vm_area_struct *vma;
9604 for (vma = mm->mmap; vma; vma = vma->vm_next) {
9608 if (perf_addr_filter_vma_adjust(filter, vma, fr))
9614 * Update event's address range filters based on the
9615 * task's existing mappings, if any.
9617 static void perf_event_addr_filters_apply(struct perf_event *event)
9619 struct perf_addr_filters_head *ifh = perf_event_addr_filters(event);
9620 struct task_struct *task = READ_ONCE(event->ctx->task);
9621 struct perf_addr_filter *filter;
9622 struct mm_struct *mm = NULL;
9623 unsigned int count = 0;
9624 unsigned long flags;
9627 * We may observe TASK_TOMBSTONE, which means that the event tear-down
9628 * will stop on the parent's child_mutex that our caller is also holding
9630 if (task == TASK_TOMBSTONE)
9633 if (ifh->nr_file_filters) {
9634 mm = get_task_mm(event->ctx->task);
9638 down_read(&mm->mmap_sem);
9641 raw_spin_lock_irqsave(&ifh->lock, flags);
9642 list_for_each_entry(filter, &ifh->list, entry) {
9643 if (filter->path.dentry) {
9645 * Adjust base offset if the filter is associated to a
9646 * binary that needs to be mapped:
9648 event->addr_filter_ranges[count].start = 0;
9649 event->addr_filter_ranges[count].size = 0;
9651 perf_addr_filter_apply(filter, mm, &event->addr_filter_ranges[count]);
9653 event->addr_filter_ranges[count].start = filter->offset;
9654 event->addr_filter_ranges[count].size = filter->size;
9660 event->addr_filters_gen++;
9661 raw_spin_unlock_irqrestore(&ifh->lock, flags);
9663 if (ifh->nr_file_filters) {
9664 up_read(&mm->mmap_sem);
9670 perf_event_stop(event, 1);
9674 * Address range filtering: limiting the data to certain
9675 * instruction address ranges. Filters are ioctl()ed to us from
9676 * userspace as ascii strings.
9678 * Filter string format:
9681 * where ACTION is one of the
9682 * * "filter": limit the trace to this region
9683 * * "start": start tracing from this address
9684 * * "stop": stop tracing at this address/region;
9686 * * for kernel addresses: <start address>[/<size>]
9687 * * for object files: <start address>[/<size>]@</path/to/object/file>
9689 * if <size> is not specified or is zero, the range is treated as a single
9690 * address; not valid for ACTION=="filter".
9704 IF_STATE_ACTION = 0,
9709 static const match_table_t if_tokens = {
9710 { IF_ACT_FILTER, "filter" },
9711 { IF_ACT_START, "start" },
9712 { IF_ACT_STOP, "stop" },
9713 { IF_SRC_FILE, "%u/%u@%s" },
9714 { IF_SRC_KERNEL, "%u/%u" },
9715 { IF_SRC_FILEADDR, "%u@%s" },
9716 { IF_SRC_KERNELADDR, "%u" },
9717 { IF_ACT_NONE, NULL },
9721 * Address filter string parser
9724 perf_event_parse_addr_filter(struct perf_event *event, char *fstr,
9725 struct list_head *filters)
9727 struct perf_addr_filter *filter = NULL;
9728 char *start, *orig, *filename = NULL;
9729 substring_t args[MAX_OPT_ARGS];
9730 int state = IF_STATE_ACTION, token;
9731 unsigned int kernel = 0;
9734 orig = fstr = kstrdup(fstr, GFP_KERNEL);
9738 while ((start = strsep(&fstr, " ,\n")) != NULL) {
9739 static const enum perf_addr_filter_action_t actions[] = {
9740 [IF_ACT_FILTER] = PERF_ADDR_FILTER_ACTION_FILTER,
9741 [IF_ACT_START] = PERF_ADDR_FILTER_ACTION_START,
9742 [IF_ACT_STOP] = PERF_ADDR_FILTER_ACTION_STOP,
9749 /* filter definition begins */
9750 if (state == IF_STATE_ACTION) {
9751 filter = perf_addr_filter_new(event, filters);
9756 token = match_token(start, if_tokens, args);
9761 if (state != IF_STATE_ACTION)
9764 filter->action = actions[token];
9765 state = IF_STATE_SOURCE;
9768 case IF_SRC_KERNELADDR:
9773 case IF_SRC_FILEADDR:
9775 if (state != IF_STATE_SOURCE)
9779 ret = kstrtoul(args[0].from, 0, &filter->offset);
9783 if (token == IF_SRC_KERNEL || token == IF_SRC_FILE) {
9785 ret = kstrtoul(args[1].from, 0, &filter->size);
9790 if (token == IF_SRC_FILE || token == IF_SRC_FILEADDR) {
9791 int fpos = token == IF_SRC_FILE ? 2 : 1;
9793 filename = match_strdup(&args[fpos]);
9800 state = IF_STATE_END;
9808 * Filter definition is fully parsed, validate and install it.
9809 * Make sure that it doesn't contradict itself or the event's
9812 if (state == IF_STATE_END) {
9814 if (kernel && event->attr.exclude_kernel)
9818 * ACTION "filter" must have a non-zero length region
9821 if (filter->action == PERF_ADDR_FILTER_ACTION_FILTER &&
9830 * For now, we only support file-based filters
9831 * in per-task events; doing so for CPU-wide
9832 * events requires additional context switching
9833 * trickery, since same object code will be
9834 * mapped at different virtual addresses in
9835 * different processes.
9838 if (!event->ctx->task)
9839 goto fail_free_name;
9841 /* look up the path and grab its inode */
9842 ret = kern_path(filename, LOOKUP_FOLLOW,
9845 goto fail_free_name;
9851 if (!filter->path.dentry ||
9852 !S_ISREG(d_inode(filter->path.dentry)
9856 event->addr_filters.nr_file_filters++;
9859 /* ready to consume more filters */
9860 state = IF_STATE_ACTION;
9865 if (state != IF_STATE_ACTION)
9875 free_filters_list(filters);
9882 perf_event_set_addr_filter(struct perf_event *event, char *filter_str)
9888 * Since this is called in perf_ioctl() path, we're already holding
9891 lockdep_assert_held(&event->ctx->mutex);
9893 if (WARN_ON_ONCE(event->parent))
9896 ret = perf_event_parse_addr_filter(event, filter_str, &filters);
9898 goto fail_clear_files;
9900 ret = event->pmu->addr_filters_validate(&filters);
9902 goto fail_free_filters;
9904 /* remove existing filters, if any */
9905 perf_addr_filters_splice(event, &filters);
9907 /* install new filters */
9908 perf_event_for_each_child(event, perf_event_addr_filters_apply);
9913 free_filters_list(&filters);
9916 event->addr_filters.nr_file_filters = 0;
9921 static int perf_event_set_filter(struct perf_event *event, void __user *arg)
9926 filter_str = strndup_user(arg, PAGE_SIZE);
9927 if (IS_ERR(filter_str))
9928 return PTR_ERR(filter_str);
9930 #ifdef CONFIG_EVENT_TRACING
9931 if (perf_event_is_tracing(event)) {
9932 struct perf_event_context *ctx = event->ctx;
9935 * Beware, here be dragons!!
9937 * the tracepoint muck will deadlock against ctx->mutex, but
9938 * the tracepoint stuff does not actually need it. So
9939 * temporarily drop ctx->mutex. As per perf_event_ctx_lock() we
9940 * already have a reference on ctx.
9942 * This can result in event getting moved to a different ctx,
9943 * but that does not affect the tracepoint state.
9945 mutex_unlock(&ctx->mutex);
9946 ret = ftrace_profile_set_filter(event, event->attr.config, filter_str);
9947 mutex_lock(&ctx->mutex);
9950 if (has_addr_filter(event))
9951 ret = perf_event_set_addr_filter(event, filter_str);
9958 * hrtimer based swevent callback
9961 static enum hrtimer_restart perf_swevent_hrtimer(struct hrtimer *hrtimer)
9963 enum hrtimer_restart ret = HRTIMER_RESTART;
9964 struct perf_sample_data data;
9965 struct pt_regs *regs;
9966 struct perf_event *event;
9969 event = container_of(hrtimer, struct perf_event, hw.hrtimer);
9971 if (event->state != PERF_EVENT_STATE_ACTIVE)
9972 return HRTIMER_NORESTART;
9974 event->pmu->read(event);
9976 perf_sample_data_init(&data, 0, event->hw.last_period);
9977 regs = get_irq_regs();
9979 if (regs && !perf_exclude_event(event, regs)) {
9980 if (!(event->attr.exclude_idle && is_idle_task(current)))
9981 if (__perf_event_overflow(event, 1, &data, regs))
9982 ret = HRTIMER_NORESTART;
9985 period = max_t(u64, 10000, event->hw.sample_period);
9986 hrtimer_forward_now(hrtimer, ns_to_ktime(period));
9991 static void perf_swevent_start_hrtimer(struct perf_event *event)
9993 struct hw_perf_event *hwc = &event->hw;
9996 if (!is_sampling_event(event))
9999 period = local64_read(&hwc->period_left);
10004 local64_set(&hwc->period_left, 0);
10006 period = max_t(u64, 10000, hwc->sample_period);
10008 hrtimer_start(&hwc->hrtimer, ns_to_ktime(period),
10009 HRTIMER_MODE_REL_PINNED_HARD);
10012 static void perf_swevent_cancel_hrtimer(struct perf_event *event)
10014 struct hw_perf_event *hwc = &event->hw;
10016 if (is_sampling_event(event)) {
10017 ktime_t remaining = hrtimer_get_remaining(&hwc->hrtimer);
10018 local64_set(&hwc->period_left, ktime_to_ns(remaining));
10020 hrtimer_cancel(&hwc->hrtimer);
10024 static void perf_swevent_init_hrtimer(struct perf_event *event)
10026 struct hw_perf_event *hwc = &event->hw;
10028 if (!is_sampling_event(event))
10031 hrtimer_init(&hwc->hrtimer, CLOCK_MONOTONIC, HRTIMER_MODE_REL_HARD);
10032 hwc->hrtimer.function = perf_swevent_hrtimer;
10035 * Since hrtimers have a fixed rate, we can do a static freq->period
10036 * mapping and avoid the whole period adjust feedback stuff.
10038 if (event->attr.freq) {
10039 long freq = event->attr.sample_freq;
10041 event->attr.sample_period = NSEC_PER_SEC / freq;
10042 hwc->sample_period = event->attr.sample_period;
10043 local64_set(&hwc->period_left, hwc->sample_period);
10044 hwc->last_period = hwc->sample_period;
10045 event->attr.freq = 0;
10050 * Software event: cpu wall time clock
10053 static void cpu_clock_event_update(struct perf_event *event)
10058 now = local_clock();
10059 prev = local64_xchg(&event->hw.prev_count, now);
10060 local64_add(now - prev, &event->count);
10063 static void cpu_clock_event_start(struct perf_event *event, int flags)
10065 local64_set(&event->hw.prev_count, local_clock());
10066 perf_swevent_start_hrtimer(event);
10069 static void cpu_clock_event_stop(struct perf_event *event, int flags)
10071 perf_swevent_cancel_hrtimer(event);
10072 cpu_clock_event_update(event);
10075 static int cpu_clock_event_add(struct perf_event *event, int flags)
10077 if (flags & PERF_EF_START)
10078 cpu_clock_event_start(event, flags);
10079 perf_event_update_userpage(event);
10084 static void cpu_clock_event_del(struct perf_event *event, int flags)
10086 cpu_clock_event_stop(event, flags);
10089 static void cpu_clock_event_read(struct perf_event *event)
10091 cpu_clock_event_update(event);
10094 static int cpu_clock_event_init(struct perf_event *event)
10096 if (event->attr.type != PERF_TYPE_SOFTWARE)
10099 if (event->attr.config != PERF_COUNT_SW_CPU_CLOCK)
10103 * no branch sampling for software events
10105 if (has_branch_stack(event))
10106 return -EOPNOTSUPP;
10108 perf_swevent_init_hrtimer(event);
10113 static struct pmu perf_cpu_clock = {
10114 .task_ctx_nr = perf_sw_context,
10116 .capabilities = PERF_PMU_CAP_NO_NMI,
10118 .event_init = cpu_clock_event_init,
10119 .add = cpu_clock_event_add,
10120 .del = cpu_clock_event_del,
10121 .start = cpu_clock_event_start,
10122 .stop = cpu_clock_event_stop,
10123 .read = cpu_clock_event_read,
10127 * Software event: task time clock
10130 static void task_clock_event_update(struct perf_event *event, u64 now)
10135 prev = local64_xchg(&event->hw.prev_count, now);
10136 delta = now - prev;
10137 local64_add(delta, &event->count);
10140 static void task_clock_event_start(struct perf_event *event, int flags)
10142 local64_set(&event->hw.prev_count, event->ctx->time);
10143 perf_swevent_start_hrtimer(event);
10146 static void task_clock_event_stop(struct perf_event *event, int flags)
10148 perf_swevent_cancel_hrtimer(event);
10149 task_clock_event_update(event, event->ctx->time);
10152 static int task_clock_event_add(struct perf_event *event, int flags)
10154 if (flags & PERF_EF_START)
10155 task_clock_event_start(event, flags);
10156 perf_event_update_userpage(event);
10161 static void task_clock_event_del(struct perf_event *event, int flags)
10163 task_clock_event_stop(event, PERF_EF_UPDATE);
10166 static void task_clock_event_read(struct perf_event *event)
10168 u64 now = perf_clock();
10169 u64 delta = now - event->ctx->timestamp;
10170 u64 time = event->ctx->time + delta;
10172 task_clock_event_update(event, time);
10175 static int task_clock_event_init(struct perf_event *event)
10177 if (event->attr.type != PERF_TYPE_SOFTWARE)
10180 if (event->attr.config != PERF_COUNT_SW_TASK_CLOCK)
10184 * no branch sampling for software events
10186 if (has_branch_stack(event))
10187 return -EOPNOTSUPP;
10189 perf_swevent_init_hrtimer(event);
10194 static struct pmu perf_task_clock = {
10195 .task_ctx_nr = perf_sw_context,
10197 .capabilities = PERF_PMU_CAP_NO_NMI,
10199 .event_init = task_clock_event_init,
10200 .add = task_clock_event_add,
10201 .del = task_clock_event_del,
10202 .start = task_clock_event_start,
10203 .stop = task_clock_event_stop,
10204 .read = task_clock_event_read,
10207 static void perf_pmu_nop_void(struct pmu *pmu)
10211 static void perf_pmu_nop_txn(struct pmu *pmu, unsigned int flags)
10215 static int perf_pmu_nop_int(struct pmu *pmu)
10220 static int perf_event_nop_int(struct perf_event *event, u64 value)
10225 static DEFINE_PER_CPU(unsigned int, nop_txn_flags);
10227 static void perf_pmu_start_txn(struct pmu *pmu, unsigned int flags)
10229 __this_cpu_write(nop_txn_flags, flags);
10231 if (flags & ~PERF_PMU_TXN_ADD)
10234 perf_pmu_disable(pmu);
10237 static int perf_pmu_commit_txn(struct pmu *pmu)
10239 unsigned int flags = __this_cpu_read(nop_txn_flags);
10241 __this_cpu_write(nop_txn_flags, 0);
10243 if (flags & ~PERF_PMU_TXN_ADD)
10246 perf_pmu_enable(pmu);
10250 static void perf_pmu_cancel_txn(struct pmu *pmu)
10252 unsigned int flags = __this_cpu_read(nop_txn_flags);
10254 __this_cpu_write(nop_txn_flags, 0);
10256 if (flags & ~PERF_PMU_TXN_ADD)
10259 perf_pmu_enable(pmu);
10262 static int perf_event_idx_default(struct perf_event *event)
10268 * Ensures all contexts with the same task_ctx_nr have the same
10269 * pmu_cpu_context too.
10271 static struct perf_cpu_context __percpu *find_pmu_context(int ctxn)
10278 list_for_each_entry(pmu, &pmus, entry) {
10279 if (pmu->task_ctx_nr == ctxn)
10280 return pmu->pmu_cpu_context;
10286 static void free_pmu_context(struct pmu *pmu)
10289 * Static contexts such as perf_sw_context have a global lifetime
10290 * and may be shared between different PMUs. Avoid freeing them
10291 * when a single PMU is going away.
10293 if (pmu->task_ctx_nr > perf_invalid_context)
10296 free_percpu(pmu->pmu_cpu_context);
10300 * Let userspace know that this PMU supports address range filtering:
10302 static ssize_t nr_addr_filters_show(struct device *dev,
10303 struct device_attribute *attr,
10306 struct pmu *pmu = dev_get_drvdata(dev);
10308 return snprintf(page, PAGE_SIZE - 1, "%d\n", pmu->nr_addr_filters);
10310 DEVICE_ATTR_RO(nr_addr_filters);
10312 static struct idr pmu_idr;
10315 type_show(struct device *dev, struct device_attribute *attr, char *page)
10317 struct pmu *pmu = dev_get_drvdata(dev);
10319 return snprintf(page, PAGE_SIZE-1, "%d\n", pmu->type);
10321 static DEVICE_ATTR_RO(type);
10324 perf_event_mux_interval_ms_show(struct device *dev,
10325 struct device_attribute *attr,
10328 struct pmu *pmu = dev_get_drvdata(dev);
10330 return snprintf(page, PAGE_SIZE-1, "%d\n", pmu->hrtimer_interval_ms);
10333 static DEFINE_MUTEX(mux_interval_mutex);
10336 perf_event_mux_interval_ms_store(struct device *dev,
10337 struct device_attribute *attr,
10338 const char *buf, size_t count)
10340 struct pmu *pmu = dev_get_drvdata(dev);
10341 int timer, cpu, ret;
10343 ret = kstrtoint(buf, 0, &timer);
10350 /* same value, noting to do */
10351 if (timer == pmu->hrtimer_interval_ms)
10354 mutex_lock(&mux_interval_mutex);
10355 pmu->hrtimer_interval_ms = timer;
10357 /* update all cpuctx for this PMU */
10359 for_each_online_cpu(cpu) {
10360 struct perf_cpu_context *cpuctx;
10361 cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
10362 cpuctx->hrtimer_interval = ns_to_ktime(NSEC_PER_MSEC * timer);
10364 cpu_function_call(cpu,
10365 (remote_function_f)perf_mux_hrtimer_restart, cpuctx);
10367 cpus_read_unlock();
10368 mutex_unlock(&mux_interval_mutex);
10372 static DEVICE_ATTR_RW(perf_event_mux_interval_ms);
10374 static struct attribute *pmu_dev_attrs[] = {
10375 &dev_attr_type.attr,
10376 &dev_attr_perf_event_mux_interval_ms.attr,
10379 ATTRIBUTE_GROUPS(pmu_dev);
10381 static int pmu_bus_running;
10382 static struct bus_type pmu_bus = {
10383 .name = "event_source",
10384 .dev_groups = pmu_dev_groups,
10387 static void pmu_dev_release(struct device *dev)
10392 static int pmu_dev_alloc(struct pmu *pmu)
10396 pmu->dev = kzalloc(sizeof(struct device), GFP_KERNEL);
10400 pmu->dev->groups = pmu->attr_groups;
10401 device_initialize(pmu->dev);
10402 ret = dev_set_name(pmu->dev, "%s", pmu->name);
10406 dev_set_drvdata(pmu->dev, pmu);
10407 pmu->dev->bus = &pmu_bus;
10408 pmu->dev->release = pmu_dev_release;
10409 ret = device_add(pmu->dev);
10413 /* For PMUs with address filters, throw in an extra attribute: */
10414 if (pmu->nr_addr_filters)
10415 ret = device_create_file(pmu->dev, &dev_attr_nr_addr_filters);
10420 if (pmu->attr_update)
10421 ret = sysfs_update_groups(&pmu->dev->kobj, pmu->attr_update);
10430 device_del(pmu->dev);
10433 put_device(pmu->dev);
10437 static struct lock_class_key cpuctx_mutex;
10438 static struct lock_class_key cpuctx_lock;
10440 int perf_pmu_register(struct pmu *pmu, const char *name, int type)
10442 int cpu, ret, max = PERF_TYPE_MAX;
10444 mutex_lock(&pmus_lock);
10446 pmu->pmu_disable_count = alloc_percpu(int);
10447 if (!pmu->pmu_disable_count)
10455 if (type != PERF_TYPE_SOFTWARE) {
10459 ret = idr_alloc(&pmu_idr, pmu, max, 0, GFP_KERNEL);
10463 WARN_ON(type >= 0 && ret != type);
10469 if (pmu_bus_running) {
10470 ret = pmu_dev_alloc(pmu);
10476 if (pmu->task_ctx_nr == perf_hw_context) {
10477 static int hw_context_taken = 0;
10480 * Other than systems with heterogeneous CPUs, it never makes
10481 * sense for two PMUs to share perf_hw_context. PMUs which are
10482 * uncore must use perf_invalid_context.
10484 if (WARN_ON_ONCE(hw_context_taken &&
10485 !(pmu->capabilities & PERF_PMU_CAP_HETEROGENEOUS_CPUS)))
10486 pmu->task_ctx_nr = perf_invalid_context;
10488 hw_context_taken = 1;
10491 pmu->pmu_cpu_context = find_pmu_context(pmu->task_ctx_nr);
10492 if (pmu->pmu_cpu_context)
10493 goto got_cpu_context;
10496 pmu->pmu_cpu_context = alloc_percpu(struct perf_cpu_context);
10497 if (!pmu->pmu_cpu_context)
10500 for_each_possible_cpu(cpu) {
10501 struct perf_cpu_context *cpuctx;
10503 cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
10504 __perf_event_init_context(&cpuctx->ctx);
10505 lockdep_set_class(&cpuctx->ctx.mutex, &cpuctx_mutex);
10506 lockdep_set_class(&cpuctx->ctx.lock, &cpuctx_lock);
10507 cpuctx->ctx.pmu = pmu;
10508 cpuctx->online = cpumask_test_cpu(cpu, perf_online_mask);
10510 __perf_mux_hrtimer_init(cpuctx, cpu);
10512 cpuctx->heap_size = ARRAY_SIZE(cpuctx->heap_default);
10513 cpuctx->heap = cpuctx->heap_default;
10517 if (!pmu->start_txn) {
10518 if (pmu->pmu_enable) {
10520 * If we have pmu_enable/pmu_disable calls, install
10521 * transaction stubs that use that to try and batch
10522 * hardware accesses.
10524 pmu->start_txn = perf_pmu_start_txn;
10525 pmu->commit_txn = perf_pmu_commit_txn;
10526 pmu->cancel_txn = perf_pmu_cancel_txn;
10528 pmu->start_txn = perf_pmu_nop_txn;
10529 pmu->commit_txn = perf_pmu_nop_int;
10530 pmu->cancel_txn = perf_pmu_nop_void;
10534 if (!pmu->pmu_enable) {
10535 pmu->pmu_enable = perf_pmu_nop_void;
10536 pmu->pmu_disable = perf_pmu_nop_void;
10539 if (!pmu->check_period)
10540 pmu->check_period = perf_event_nop_int;
10542 if (!pmu->event_idx)
10543 pmu->event_idx = perf_event_idx_default;
10546 * Ensure the TYPE_SOFTWARE PMUs are at the head of the list,
10547 * since these cannot be in the IDR. This way the linear search
10548 * is fast, provided a valid software event is provided.
10550 if (type == PERF_TYPE_SOFTWARE || !name)
10551 list_add_rcu(&pmu->entry, &pmus);
10553 list_add_tail_rcu(&pmu->entry, &pmus);
10555 atomic_set(&pmu->exclusive_cnt, 0);
10558 mutex_unlock(&pmus_lock);
10563 device_del(pmu->dev);
10564 put_device(pmu->dev);
10567 if (pmu->type != PERF_TYPE_SOFTWARE)
10568 idr_remove(&pmu_idr, pmu->type);
10571 free_percpu(pmu->pmu_disable_count);
10574 EXPORT_SYMBOL_GPL(perf_pmu_register);
10576 void perf_pmu_unregister(struct pmu *pmu)
10578 mutex_lock(&pmus_lock);
10579 list_del_rcu(&pmu->entry);
10582 * We dereference the pmu list under both SRCU and regular RCU, so
10583 * synchronize against both of those.
10585 synchronize_srcu(&pmus_srcu);
10588 free_percpu(pmu->pmu_disable_count);
10589 if (pmu->type != PERF_TYPE_SOFTWARE)
10590 idr_remove(&pmu_idr, pmu->type);
10591 if (pmu_bus_running) {
10592 if (pmu->nr_addr_filters)
10593 device_remove_file(pmu->dev, &dev_attr_nr_addr_filters);
10594 device_del(pmu->dev);
10595 put_device(pmu->dev);
10597 free_pmu_context(pmu);
10598 mutex_unlock(&pmus_lock);
10600 EXPORT_SYMBOL_GPL(perf_pmu_unregister);
10602 static inline bool has_extended_regs(struct perf_event *event)
10604 return (event->attr.sample_regs_user & PERF_REG_EXTENDED_MASK) ||
10605 (event->attr.sample_regs_intr & PERF_REG_EXTENDED_MASK);
10608 static int perf_try_init_event(struct pmu *pmu, struct perf_event *event)
10610 struct perf_event_context *ctx = NULL;
10613 if (!try_module_get(pmu->module))
10617 * A number of pmu->event_init() methods iterate the sibling_list to,
10618 * for example, validate if the group fits on the PMU. Therefore,
10619 * if this is a sibling event, acquire the ctx->mutex to protect
10620 * the sibling_list.
10622 if (event->group_leader != event && pmu->task_ctx_nr != perf_sw_context) {
10624 * This ctx->mutex can nest when we're called through
10625 * inheritance. See the perf_event_ctx_lock_nested() comment.
10627 ctx = perf_event_ctx_lock_nested(event->group_leader,
10628 SINGLE_DEPTH_NESTING);
10633 ret = pmu->event_init(event);
10636 perf_event_ctx_unlock(event->group_leader, ctx);
10639 if (!(pmu->capabilities & PERF_PMU_CAP_EXTENDED_REGS) &&
10640 has_extended_regs(event))
10643 if (pmu->capabilities & PERF_PMU_CAP_NO_EXCLUDE &&
10644 event_has_any_exclude_flag(event))
10647 if (ret && event->destroy)
10648 event->destroy(event);
10652 module_put(pmu->module);
10657 static struct pmu *perf_init_event(struct perf_event *event)
10659 int idx, type, ret;
10662 idx = srcu_read_lock(&pmus_srcu);
10664 /* Try parent's PMU first: */
10665 if (event->parent && event->parent->pmu) {
10666 pmu = event->parent->pmu;
10667 ret = perf_try_init_event(pmu, event);
10673 * PERF_TYPE_HARDWARE and PERF_TYPE_HW_CACHE
10674 * are often aliases for PERF_TYPE_RAW.
10676 type = event->attr.type;
10677 if (type == PERF_TYPE_HARDWARE || type == PERF_TYPE_HW_CACHE)
10678 type = PERF_TYPE_RAW;
10682 pmu = idr_find(&pmu_idr, type);
10685 ret = perf_try_init_event(pmu, event);
10686 if (ret == -ENOENT && event->attr.type != type) {
10687 type = event->attr.type;
10692 pmu = ERR_PTR(ret);
10697 list_for_each_entry_rcu(pmu, &pmus, entry, lockdep_is_held(&pmus_srcu)) {
10698 ret = perf_try_init_event(pmu, event);
10702 if (ret != -ENOENT) {
10703 pmu = ERR_PTR(ret);
10707 pmu = ERR_PTR(-ENOENT);
10709 srcu_read_unlock(&pmus_srcu, idx);
10714 static void attach_sb_event(struct perf_event *event)
10716 struct pmu_event_list *pel = per_cpu_ptr(&pmu_sb_events, event->cpu);
10718 raw_spin_lock(&pel->lock);
10719 list_add_rcu(&event->sb_list, &pel->list);
10720 raw_spin_unlock(&pel->lock);
10724 * We keep a list of all !task (and therefore per-cpu) events
10725 * that need to receive side-band records.
10727 * This avoids having to scan all the various PMU per-cpu contexts
10728 * looking for them.
10730 static void account_pmu_sb_event(struct perf_event *event)
10732 if (is_sb_event(event))
10733 attach_sb_event(event);
10736 static void account_event_cpu(struct perf_event *event, int cpu)
10741 if (is_cgroup_event(event))
10742 atomic_inc(&per_cpu(perf_cgroup_events, cpu));
10745 /* Freq events need the tick to stay alive (see perf_event_task_tick). */
10746 static void account_freq_event_nohz(void)
10748 #ifdef CONFIG_NO_HZ_FULL
10749 /* Lock so we don't race with concurrent unaccount */
10750 spin_lock(&nr_freq_lock);
10751 if (atomic_inc_return(&nr_freq_events) == 1)
10752 tick_nohz_dep_set(TICK_DEP_BIT_PERF_EVENTS);
10753 spin_unlock(&nr_freq_lock);
10757 static void account_freq_event(void)
10759 if (tick_nohz_full_enabled())
10760 account_freq_event_nohz();
10762 atomic_inc(&nr_freq_events);
10766 static void account_event(struct perf_event *event)
10773 if (event->attach_state & PERF_ATTACH_TASK)
10775 if (event->attr.mmap || event->attr.mmap_data)
10776 atomic_inc(&nr_mmap_events);
10777 if (event->attr.comm)
10778 atomic_inc(&nr_comm_events);
10779 if (event->attr.namespaces)
10780 atomic_inc(&nr_namespaces_events);
10781 if (event->attr.task)
10782 atomic_inc(&nr_task_events);
10783 if (event->attr.freq)
10784 account_freq_event();
10785 if (event->attr.context_switch) {
10786 atomic_inc(&nr_switch_events);
10789 if (has_branch_stack(event))
10791 if (is_cgroup_event(event))
10793 if (event->attr.ksymbol)
10794 atomic_inc(&nr_ksymbol_events);
10795 if (event->attr.bpf_event)
10796 atomic_inc(&nr_bpf_events);
10800 * We need the mutex here because static_branch_enable()
10801 * must complete *before* the perf_sched_count increment
10804 if (atomic_inc_not_zero(&perf_sched_count))
10807 mutex_lock(&perf_sched_mutex);
10808 if (!atomic_read(&perf_sched_count)) {
10809 static_branch_enable(&perf_sched_events);
10811 * Guarantee that all CPUs observe they key change and
10812 * call the perf scheduling hooks before proceeding to
10813 * install events that need them.
10818 * Now that we have waited for the sync_sched(), allow further
10819 * increments to by-pass the mutex.
10821 atomic_inc(&perf_sched_count);
10822 mutex_unlock(&perf_sched_mutex);
10826 account_event_cpu(event, event->cpu);
10828 account_pmu_sb_event(event);
10832 * Allocate and initialize an event structure
10834 static struct perf_event *
10835 perf_event_alloc(struct perf_event_attr *attr, int cpu,
10836 struct task_struct *task,
10837 struct perf_event *group_leader,
10838 struct perf_event *parent_event,
10839 perf_overflow_handler_t overflow_handler,
10840 void *context, int cgroup_fd)
10843 struct perf_event *event;
10844 struct hw_perf_event *hwc;
10845 long err = -EINVAL;
10847 if ((unsigned)cpu >= nr_cpu_ids) {
10848 if (!task || cpu != -1)
10849 return ERR_PTR(-EINVAL);
10852 event = kzalloc(sizeof(*event), GFP_KERNEL);
10854 return ERR_PTR(-ENOMEM);
10857 * Single events are their own group leaders, with an
10858 * empty sibling list:
10861 group_leader = event;
10863 mutex_init(&event->child_mutex);
10864 INIT_LIST_HEAD(&event->child_list);
10866 INIT_LIST_HEAD(&event->event_entry);
10867 INIT_LIST_HEAD(&event->sibling_list);
10868 INIT_LIST_HEAD(&event->active_list);
10869 init_event_group(event);
10870 INIT_LIST_HEAD(&event->rb_entry);
10871 INIT_LIST_HEAD(&event->active_entry);
10872 INIT_LIST_HEAD(&event->addr_filters.list);
10873 INIT_HLIST_NODE(&event->hlist_entry);
10876 init_waitqueue_head(&event->waitq);
10877 event->pending_disable = -1;
10878 init_irq_work(&event->pending, perf_pending_event);
10880 mutex_init(&event->mmap_mutex);
10881 raw_spin_lock_init(&event->addr_filters.lock);
10883 atomic_long_set(&event->refcount, 1);
10885 event->attr = *attr;
10886 event->group_leader = group_leader;
10890 event->parent = parent_event;
10892 event->ns = get_pid_ns(task_active_pid_ns(current));
10893 event->id = atomic64_inc_return(&perf_event_id);
10895 event->state = PERF_EVENT_STATE_INACTIVE;
10898 event->attach_state = PERF_ATTACH_TASK;
10900 * XXX pmu::event_init needs to know what task to account to
10901 * and we cannot use the ctx information because we need the
10902 * pmu before we get a ctx.
10904 event->hw.target = get_task_struct(task);
10907 event->clock = &local_clock;
10909 event->clock = parent_event->clock;
10911 if (!overflow_handler && parent_event) {
10912 overflow_handler = parent_event->overflow_handler;
10913 context = parent_event->overflow_handler_context;
10914 #if defined(CONFIG_BPF_SYSCALL) && defined(CONFIG_EVENT_TRACING)
10915 if (overflow_handler == bpf_overflow_handler) {
10916 struct bpf_prog *prog = parent_event->prog;
10918 bpf_prog_inc(prog);
10919 event->prog = prog;
10920 event->orig_overflow_handler =
10921 parent_event->orig_overflow_handler;
10926 if (overflow_handler) {
10927 event->overflow_handler = overflow_handler;
10928 event->overflow_handler_context = context;
10929 } else if (is_write_backward(event)){
10930 event->overflow_handler = perf_event_output_backward;
10931 event->overflow_handler_context = NULL;
10933 event->overflow_handler = perf_event_output_forward;
10934 event->overflow_handler_context = NULL;
10937 perf_event__state_init(event);
10942 hwc->sample_period = attr->sample_period;
10943 if (attr->freq && attr->sample_freq)
10944 hwc->sample_period = 1;
10945 hwc->last_period = hwc->sample_period;
10947 local64_set(&hwc->period_left, hwc->sample_period);
10950 * We currently do not support PERF_SAMPLE_READ on inherited events.
10951 * See perf_output_read().
10953 if (attr->inherit && (attr->sample_type & PERF_SAMPLE_READ))
10956 if (!has_branch_stack(event))
10957 event->attr.branch_sample_type = 0;
10959 pmu = perf_init_event(event);
10961 err = PTR_ERR(pmu);
10966 * Disallow uncore-cgroup events, they don't make sense as the cgroup will
10967 * be different on other CPUs in the uncore mask.
10969 if (pmu->task_ctx_nr == perf_invalid_context && cgroup_fd != -1) {
10974 if (event->attr.aux_output &&
10975 !(pmu->capabilities & PERF_PMU_CAP_AUX_OUTPUT)) {
10980 if (cgroup_fd != -1) {
10981 err = perf_cgroup_connect(cgroup_fd, event, attr, group_leader);
10986 err = exclusive_event_init(event);
10990 if (has_addr_filter(event)) {
10991 event->addr_filter_ranges = kcalloc(pmu->nr_addr_filters,
10992 sizeof(struct perf_addr_filter_range),
10994 if (!event->addr_filter_ranges) {
11000 * Clone the parent's vma offsets: they are valid until exec()
11001 * even if the mm is not shared with the parent.
11003 if (event->parent) {
11004 struct perf_addr_filters_head *ifh = perf_event_addr_filters(event);
11006 raw_spin_lock_irq(&ifh->lock);
11007 memcpy(event->addr_filter_ranges,
11008 event->parent->addr_filter_ranges,
11009 pmu->nr_addr_filters * sizeof(struct perf_addr_filter_range));
11010 raw_spin_unlock_irq(&ifh->lock);
11013 /* force hw sync on the address filters */
11014 event->addr_filters_gen = 1;
11017 if (!event->parent) {
11018 if (event->attr.sample_type & PERF_SAMPLE_CALLCHAIN) {
11019 err = get_callchain_buffers(attr->sample_max_stack);
11021 goto err_addr_filters;
11025 err = security_perf_event_alloc(event);
11027 goto err_callchain_buffer;
11029 /* symmetric to unaccount_event() in _free_event() */
11030 account_event(event);
11034 err_callchain_buffer:
11035 if (!event->parent) {
11036 if (event->attr.sample_type & PERF_SAMPLE_CALLCHAIN)
11037 put_callchain_buffers();
11040 kfree(event->addr_filter_ranges);
11043 exclusive_event_destroy(event);
11046 if (is_cgroup_event(event))
11047 perf_detach_cgroup(event);
11048 if (event->destroy)
11049 event->destroy(event);
11050 module_put(pmu->module);
11053 put_pid_ns(event->ns);
11054 if (event->hw.target)
11055 put_task_struct(event->hw.target);
11058 return ERR_PTR(err);
11061 static int perf_copy_attr(struct perf_event_attr __user *uattr,
11062 struct perf_event_attr *attr)
11067 /* Zero the full structure, so that a short copy will be nice. */
11068 memset(attr, 0, sizeof(*attr));
11070 ret = get_user(size, &uattr->size);
11074 /* ABI compatibility quirk: */
11076 size = PERF_ATTR_SIZE_VER0;
11077 if (size < PERF_ATTR_SIZE_VER0 || size > PAGE_SIZE)
11080 ret = copy_struct_from_user(attr, sizeof(*attr), uattr, size);
11089 if (attr->__reserved_1 || attr->__reserved_2 || attr->__reserved_3)
11092 if (attr->sample_type & ~(PERF_SAMPLE_MAX-1))
11095 if (attr->read_format & ~(PERF_FORMAT_MAX-1))
11098 if (attr->sample_type & PERF_SAMPLE_BRANCH_STACK) {
11099 u64 mask = attr->branch_sample_type;
11101 /* only using defined bits */
11102 if (mask & ~(PERF_SAMPLE_BRANCH_MAX-1))
11105 /* at least one branch bit must be set */
11106 if (!(mask & ~PERF_SAMPLE_BRANCH_PLM_ALL))
11109 /* propagate priv level, when not set for branch */
11110 if (!(mask & PERF_SAMPLE_BRANCH_PLM_ALL)) {
11112 /* exclude_kernel checked on syscall entry */
11113 if (!attr->exclude_kernel)
11114 mask |= PERF_SAMPLE_BRANCH_KERNEL;
11116 if (!attr->exclude_user)
11117 mask |= PERF_SAMPLE_BRANCH_USER;
11119 if (!attr->exclude_hv)
11120 mask |= PERF_SAMPLE_BRANCH_HV;
11122 * adjust user setting (for HW filter setup)
11124 attr->branch_sample_type = mask;
11126 /* privileged levels capture (kernel, hv): check permissions */
11127 if (mask & PERF_SAMPLE_BRANCH_PERM_PLM) {
11128 ret = perf_allow_kernel(attr);
11134 if (attr->sample_type & PERF_SAMPLE_REGS_USER) {
11135 ret = perf_reg_validate(attr->sample_regs_user);
11140 if (attr->sample_type & PERF_SAMPLE_STACK_USER) {
11141 if (!arch_perf_have_user_stack_dump())
11145 * We have __u32 type for the size, but so far
11146 * we can only use __u16 as maximum due to the
11147 * __u16 sample size limit.
11149 if (attr->sample_stack_user >= USHRT_MAX)
11151 else if (!IS_ALIGNED(attr->sample_stack_user, sizeof(u64)))
11155 if (!attr->sample_max_stack)
11156 attr->sample_max_stack = sysctl_perf_event_max_stack;
11158 if (attr->sample_type & PERF_SAMPLE_REGS_INTR)
11159 ret = perf_reg_validate(attr->sample_regs_intr);
11164 put_user(sizeof(*attr), &uattr->size);
11170 perf_event_set_output(struct perf_event *event, struct perf_event *output_event)
11172 struct perf_buffer *rb = NULL;
11178 /* don't allow circular references */
11179 if (event == output_event)
11183 * Don't allow cross-cpu buffers
11185 if (output_event->cpu != event->cpu)
11189 * If its not a per-cpu rb, it must be the same task.
11191 if (output_event->cpu == -1 && output_event->ctx != event->ctx)
11195 * Mixing clocks in the same buffer is trouble you don't need.
11197 if (output_event->clock != event->clock)
11201 * Either writing ring buffer from beginning or from end.
11202 * Mixing is not allowed.
11204 if (is_write_backward(output_event) != is_write_backward(event))
11208 * If both events generate aux data, they must be on the same PMU
11210 if (has_aux(event) && has_aux(output_event) &&
11211 event->pmu != output_event->pmu)
11215 mutex_lock(&event->mmap_mutex);
11216 /* Can't redirect output if we've got an active mmap() */
11217 if (atomic_read(&event->mmap_count))
11220 if (output_event) {
11221 /* get the rb we want to redirect to */
11222 rb = ring_buffer_get(output_event);
11227 ring_buffer_attach(event, rb);
11231 mutex_unlock(&event->mmap_mutex);
11237 static void mutex_lock_double(struct mutex *a, struct mutex *b)
11243 mutex_lock_nested(b, SINGLE_DEPTH_NESTING);
11246 static int perf_event_set_clock(struct perf_event *event, clockid_t clk_id)
11248 bool nmi_safe = false;
11251 case CLOCK_MONOTONIC:
11252 event->clock = &ktime_get_mono_fast_ns;
11256 case CLOCK_MONOTONIC_RAW:
11257 event->clock = &ktime_get_raw_fast_ns;
11261 case CLOCK_REALTIME:
11262 event->clock = &ktime_get_real_ns;
11265 case CLOCK_BOOTTIME:
11266 event->clock = &ktime_get_boottime_ns;
11270 event->clock = &ktime_get_clocktai_ns;
11277 if (!nmi_safe && !(event->pmu->capabilities & PERF_PMU_CAP_NO_NMI))
11284 * Variation on perf_event_ctx_lock_nested(), except we take two context
11287 static struct perf_event_context *
11288 __perf_event_ctx_lock_double(struct perf_event *group_leader,
11289 struct perf_event_context *ctx)
11291 struct perf_event_context *gctx;
11295 gctx = READ_ONCE(group_leader->ctx);
11296 if (!refcount_inc_not_zero(&gctx->refcount)) {
11302 mutex_lock_double(&gctx->mutex, &ctx->mutex);
11304 if (group_leader->ctx != gctx) {
11305 mutex_unlock(&ctx->mutex);
11306 mutex_unlock(&gctx->mutex);
11315 * sys_perf_event_open - open a performance event, associate it to a task/cpu
11317 * @attr_uptr: event_id type attributes for monitoring/sampling
11320 * @group_fd: group leader event fd
11322 SYSCALL_DEFINE5(perf_event_open,
11323 struct perf_event_attr __user *, attr_uptr,
11324 pid_t, pid, int, cpu, int, group_fd, unsigned long, flags)
11326 struct perf_event *group_leader = NULL, *output_event = NULL;
11327 struct perf_event *event, *sibling;
11328 struct perf_event_attr attr;
11329 struct perf_event_context *ctx, *uninitialized_var(gctx);
11330 struct file *event_file = NULL;
11331 struct fd group = {NULL, 0};
11332 struct task_struct *task = NULL;
11335 int move_group = 0;
11337 int f_flags = O_RDWR;
11338 int cgroup_fd = -1;
11340 /* for future expandability... */
11341 if (flags & ~PERF_FLAG_ALL)
11344 /* Do we allow access to perf_event_open(2) ? */
11345 err = security_perf_event_open(&attr, PERF_SECURITY_OPEN);
11349 err = perf_copy_attr(attr_uptr, &attr);
11353 if (!attr.exclude_kernel) {
11354 err = perf_allow_kernel(&attr);
11359 if (attr.namespaces) {
11360 if (!capable(CAP_SYS_ADMIN))
11365 if (attr.sample_freq > sysctl_perf_event_sample_rate)
11368 if (attr.sample_period & (1ULL << 63))
11372 /* Only privileged users can get physical addresses */
11373 if ((attr.sample_type & PERF_SAMPLE_PHYS_ADDR)) {
11374 err = perf_allow_kernel(&attr);
11379 err = security_locked_down(LOCKDOWN_PERF);
11380 if (err && (attr.sample_type & PERF_SAMPLE_REGS_INTR))
11381 /* REGS_INTR can leak data, lockdown must prevent this */
11387 * In cgroup mode, the pid argument is used to pass the fd
11388 * opened to the cgroup directory in cgroupfs. The cpu argument
11389 * designates the cpu on which to monitor threads from that
11392 if ((flags & PERF_FLAG_PID_CGROUP) && (pid == -1 || cpu == -1))
11395 if (flags & PERF_FLAG_FD_CLOEXEC)
11396 f_flags |= O_CLOEXEC;
11398 event_fd = get_unused_fd_flags(f_flags);
11402 if (group_fd != -1) {
11403 err = perf_fget_light(group_fd, &group);
11406 group_leader = group.file->private_data;
11407 if (flags & PERF_FLAG_FD_OUTPUT)
11408 output_event = group_leader;
11409 if (flags & PERF_FLAG_FD_NO_GROUP)
11410 group_leader = NULL;
11413 if (pid != -1 && !(flags & PERF_FLAG_PID_CGROUP)) {
11414 task = find_lively_task_by_vpid(pid);
11415 if (IS_ERR(task)) {
11416 err = PTR_ERR(task);
11421 if (task && group_leader &&
11422 group_leader->attr.inherit != attr.inherit) {
11428 err = mutex_lock_interruptible(&task->signal->exec_update_mutex);
11433 * Reuse ptrace permission checks for now.
11435 * We must hold exec_update_mutex across this and any potential
11436 * perf_install_in_context() call for this new event to
11437 * serialize against exec() altering our credentials (and the
11438 * perf_event_exit_task() that could imply).
11441 if (!ptrace_may_access(task, PTRACE_MODE_READ_REALCREDS))
11445 if (flags & PERF_FLAG_PID_CGROUP)
11448 event = perf_event_alloc(&attr, cpu, task, group_leader, NULL,
11449 NULL, NULL, cgroup_fd);
11450 if (IS_ERR(event)) {
11451 err = PTR_ERR(event);
11455 if (is_sampling_event(event)) {
11456 if (event->pmu->capabilities & PERF_PMU_CAP_NO_INTERRUPT) {
11463 * Special case software events and allow them to be part of
11464 * any hardware group.
11468 if (attr.use_clockid) {
11469 err = perf_event_set_clock(event, attr.clockid);
11474 if (pmu->task_ctx_nr == perf_sw_context)
11475 event->event_caps |= PERF_EV_CAP_SOFTWARE;
11477 if (group_leader) {
11478 if (is_software_event(event) &&
11479 !in_software_context(group_leader)) {
11481 * If the event is a sw event, but the group_leader
11482 * is on hw context.
11484 * Allow the addition of software events to hw
11485 * groups, this is safe because software events
11486 * never fail to schedule.
11488 pmu = group_leader->ctx->pmu;
11489 } else if (!is_software_event(event) &&
11490 is_software_event(group_leader) &&
11491 (group_leader->group_caps & PERF_EV_CAP_SOFTWARE)) {
11493 * In case the group is a pure software group, and we
11494 * try to add a hardware event, move the whole group to
11495 * the hardware context.
11502 * Get the target context (task or percpu):
11504 ctx = find_get_context(pmu, task, event);
11506 err = PTR_ERR(ctx);
11511 * Look up the group leader (we will attach this event to it):
11513 if (group_leader) {
11517 * Do not allow a recursive hierarchy (this new sibling
11518 * becoming part of another group-sibling):
11520 if (group_leader->group_leader != group_leader)
11523 /* All events in a group should have the same clock */
11524 if (group_leader->clock != event->clock)
11528 * Make sure we're both events for the same CPU;
11529 * grouping events for different CPUs is broken; since
11530 * you can never concurrently schedule them anyhow.
11532 if (group_leader->cpu != event->cpu)
11536 * Make sure we're both on the same task, or both
11539 if (group_leader->ctx->task != ctx->task)
11543 * Do not allow to attach to a group in a different task
11544 * or CPU context. If we're moving SW events, we'll fix
11545 * this up later, so allow that.
11547 if (!move_group && group_leader->ctx != ctx)
11551 * Only a group leader can be exclusive or pinned
11553 if (attr.exclusive || attr.pinned)
11557 if (output_event) {
11558 err = perf_event_set_output(event, output_event);
11563 event_file = anon_inode_getfile("[perf_event]", &perf_fops, event,
11565 if (IS_ERR(event_file)) {
11566 err = PTR_ERR(event_file);
11572 gctx = __perf_event_ctx_lock_double(group_leader, ctx);
11574 if (gctx->task == TASK_TOMBSTONE) {
11580 * Check if we raced against another sys_perf_event_open() call
11581 * moving the software group underneath us.
11583 if (!(group_leader->group_caps & PERF_EV_CAP_SOFTWARE)) {
11585 * If someone moved the group out from under us, check
11586 * if this new event wound up on the same ctx, if so
11587 * its the regular !move_group case, otherwise fail.
11593 perf_event_ctx_unlock(group_leader, gctx);
11599 * Failure to create exclusive events returns -EBUSY.
11602 if (!exclusive_event_installable(group_leader, ctx))
11605 for_each_sibling_event(sibling, group_leader) {
11606 if (!exclusive_event_installable(sibling, ctx))
11610 mutex_lock(&ctx->mutex);
11613 if (ctx->task == TASK_TOMBSTONE) {
11618 if (!perf_event_validate_size(event)) {
11625 * Check if the @cpu we're creating an event for is online.
11627 * We use the perf_cpu_context::ctx::mutex to serialize against
11628 * the hotplug notifiers. See perf_event_{init,exit}_cpu().
11630 struct perf_cpu_context *cpuctx =
11631 container_of(ctx, struct perf_cpu_context, ctx);
11633 if (!cpuctx->online) {
11639 if (perf_need_aux_event(event) && !perf_get_aux_event(event, group_leader)) {
11645 * Must be under the same ctx::mutex as perf_install_in_context(),
11646 * because we need to serialize with concurrent event creation.
11648 if (!exclusive_event_installable(event, ctx)) {
11653 WARN_ON_ONCE(ctx->parent_ctx);
11656 * This is the point on no return; we cannot fail hereafter. This is
11657 * where we start modifying current state.
11662 * See perf_event_ctx_lock() for comments on the details
11663 * of swizzling perf_event::ctx.
11665 perf_remove_from_context(group_leader, 0);
11668 for_each_sibling_event(sibling, group_leader) {
11669 perf_remove_from_context(sibling, 0);
11674 * Wait for everybody to stop referencing the events through
11675 * the old lists, before installing it on new lists.
11680 * Install the group siblings before the group leader.
11682 * Because a group leader will try and install the entire group
11683 * (through the sibling list, which is still in-tact), we can
11684 * end up with siblings installed in the wrong context.
11686 * By installing siblings first we NO-OP because they're not
11687 * reachable through the group lists.
11689 for_each_sibling_event(sibling, group_leader) {
11690 perf_event__state_init(sibling);
11691 perf_install_in_context(ctx, sibling, sibling->cpu);
11696 * Removing from the context ends up with disabled
11697 * event. What we want here is event in the initial
11698 * startup state, ready to be add into new context.
11700 perf_event__state_init(group_leader);
11701 perf_install_in_context(ctx, group_leader, group_leader->cpu);
11706 * Precalculate sample_data sizes; do while holding ctx::mutex such
11707 * that we're serialized against further additions and before
11708 * perf_install_in_context() which is the point the event is active and
11709 * can use these values.
11711 perf_event__header_size(event);
11712 perf_event__id_header_size(event);
11714 event->owner = current;
11716 perf_install_in_context(ctx, event, event->cpu);
11717 perf_unpin_context(ctx);
11720 perf_event_ctx_unlock(group_leader, gctx);
11721 mutex_unlock(&ctx->mutex);
11724 mutex_unlock(&task->signal->exec_update_mutex);
11725 put_task_struct(task);
11728 mutex_lock(¤t->perf_event_mutex);
11729 list_add_tail(&event->owner_entry, ¤t->perf_event_list);
11730 mutex_unlock(¤t->perf_event_mutex);
11733 * Drop the reference on the group_event after placing the
11734 * new event on the sibling_list. This ensures destruction
11735 * of the group leader will find the pointer to itself in
11736 * perf_group_detach().
11739 fd_install(event_fd, event_file);
11744 perf_event_ctx_unlock(group_leader, gctx);
11745 mutex_unlock(&ctx->mutex);
11749 perf_unpin_context(ctx);
11753 * If event_file is set, the fput() above will have called ->release()
11754 * and that will take care of freeing the event.
11760 mutex_unlock(&task->signal->exec_update_mutex);
11763 put_task_struct(task);
11767 put_unused_fd(event_fd);
11772 * perf_event_create_kernel_counter
11774 * @attr: attributes of the counter to create
11775 * @cpu: cpu in which the counter is bound
11776 * @task: task to profile (NULL for percpu)
11778 struct perf_event *
11779 perf_event_create_kernel_counter(struct perf_event_attr *attr, int cpu,
11780 struct task_struct *task,
11781 perf_overflow_handler_t overflow_handler,
11784 struct perf_event_context *ctx;
11785 struct perf_event *event;
11789 * Grouping is not supported for kernel events, neither is 'AUX',
11790 * make sure the caller's intentions are adjusted.
11792 if (attr->aux_output)
11793 return ERR_PTR(-EINVAL);
11795 event = perf_event_alloc(attr, cpu, task, NULL, NULL,
11796 overflow_handler, context, -1);
11797 if (IS_ERR(event)) {
11798 err = PTR_ERR(event);
11802 /* Mark owner so we could distinguish it from user events. */
11803 event->owner = TASK_TOMBSTONE;
11806 * Get the target context (task or percpu):
11808 ctx = find_get_context(event->pmu, task, event);
11810 err = PTR_ERR(ctx);
11814 WARN_ON_ONCE(ctx->parent_ctx);
11815 mutex_lock(&ctx->mutex);
11816 if (ctx->task == TASK_TOMBSTONE) {
11823 * Check if the @cpu we're creating an event for is online.
11825 * We use the perf_cpu_context::ctx::mutex to serialize against
11826 * the hotplug notifiers. See perf_event_{init,exit}_cpu().
11828 struct perf_cpu_context *cpuctx =
11829 container_of(ctx, struct perf_cpu_context, ctx);
11830 if (!cpuctx->online) {
11836 if (!exclusive_event_installable(event, ctx)) {
11841 perf_install_in_context(ctx, event, event->cpu);
11842 perf_unpin_context(ctx);
11843 mutex_unlock(&ctx->mutex);
11848 mutex_unlock(&ctx->mutex);
11849 perf_unpin_context(ctx);
11854 return ERR_PTR(err);
11856 EXPORT_SYMBOL_GPL(perf_event_create_kernel_counter);
11858 void perf_pmu_migrate_context(struct pmu *pmu, int src_cpu, int dst_cpu)
11860 struct perf_event_context *src_ctx;
11861 struct perf_event_context *dst_ctx;
11862 struct perf_event *event, *tmp;
11865 src_ctx = &per_cpu_ptr(pmu->pmu_cpu_context, src_cpu)->ctx;
11866 dst_ctx = &per_cpu_ptr(pmu->pmu_cpu_context, dst_cpu)->ctx;
11869 * See perf_event_ctx_lock() for comments on the details
11870 * of swizzling perf_event::ctx.
11872 mutex_lock_double(&src_ctx->mutex, &dst_ctx->mutex);
11873 list_for_each_entry_safe(event, tmp, &src_ctx->event_list,
11875 perf_remove_from_context(event, 0);
11876 unaccount_event_cpu(event, src_cpu);
11878 list_add(&event->migrate_entry, &events);
11882 * Wait for the events to quiesce before re-instating them.
11887 * Re-instate events in 2 passes.
11889 * Skip over group leaders and only install siblings on this first
11890 * pass, siblings will not get enabled without a leader, however a
11891 * leader will enable its siblings, even if those are still on the old
11894 list_for_each_entry_safe(event, tmp, &events, migrate_entry) {
11895 if (event->group_leader == event)
11898 list_del(&event->migrate_entry);
11899 if (event->state >= PERF_EVENT_STATE_OFF)
11900 event->state = PERF_EVENT_STATE_INACTIVE;
11901 account_event_cpu(event, dst_cpu);
11902 perf_install_in_context(dst_ctx, event, dst_cpu);
11907 * Once all the siblings are setup properly, install the group leaders
11910 list_for_each_entry_safe(event, tmp, &events, migrate_entry) {
11911 list_del(&event->migrate_entry);
11912 if (event->state >= PERF_EVENT_STATE_OFF)
11913 event->state = PERF_EVENT_STATE_INACTIVE;
11914 account_event_cpu(event, dst_cpu);
11915 perf_install_in_context(dst_ctx, event, dst_cpu);
11918 mutex_unlock(&dst_ctx->mutex);
11919 mutex_unlock(&src_ctx->mutex);
11921 EXPORT_SYMBOL_GPL(perf_pmu_migrate_context);
11923 static void sync_child_event(struct perf_event *child_event,
11924 struct task_struct *child)
11926 struct perf_event *parent_event = child_event->parent;
11929 if (child_event->attr.inherit_stat)
11930 perf_event_read_event(child_event, child);
11932 child_val = perf_event_count(child_event);
11935 * Add back the child's count to the parent's count:
11937 atomic64_add(child_val, &parent_event->child_count);
11938 atomic64_add(child_event->total_time_enabled,
11939 &parent_event->child_total_time_enabled);
11940 atomic64_add(child_event->total_time_running,
11941 &parent_event->child_total_time_running);
11945 perf_event_exit_event(struct perf_event *child_event,
11946 struct perf_event_context *child_ctx,
11947 struct task_struct *child)
11949 struct perf_event *parent_event = child_event->parent;
11952 * Do not destroy the 'original' grouping; because of the context
11953 * switch optimization the original events could've ended up in a
11954 * random child task.
11956 * If we were to destroy the original group, all group related
11957 * operations would cease to function properly after this random
11960 * Do destroy all inherited groups, we don't care about those
11961 * and being thorough is better.
11963 raw_spin_lock_irq(&child_ctx->lock);
11964 WARN_ON_ONCE(child_ctx->is_active);
11967 perf_group_detach(child_event);
11968 list_del_event(child_event, child_ctx);
11969 perf_event_set_state(child_event, PERF_EVENT_STATE_EXIT); /* is_event_hup() */
11970 raw_spin_unlock_irq(&child_ctx->lock);
11973 * Parent events are governed by their filedesc, retain them.
11975 if (!parent_event) {
11976 perf_event_wakeup(child_event);
11980 * Child events can be cleaned up.
11983 sync_child_event(child_event, child);
11986 * Remove this event from the parent's list
11988 WARN_ON_ONCE(parent_event->ctx->parent_ctx);
11989 mutex_lock(&parent_event->child_mutex);
11990 list_del_init(&child_event->child_list);
11991 mutex_unlock(&parent_event->child_mutex);
11994 * Kick perf_poll() for is_event_hup().
11996 perf_event_wakeup(parent_event);
11997 free_event(child_event);
11998 put_event(parent_event);
12001 static void perf_event_exit_task_context(struct task_struct *child, int ctxn)
12003 struct perf_event_context *child_ctx, *clone_ctx = NULL;
12004 struct perf_event *child_event, *next;
12006 WARN_ON_ONCE(child != current);
12008 child_ctx = perf_pin_task_context(child, ctxn);
12013 * In order to reduce the amount of tricky in ctx tear-down, we hold
12014 * ctx::mutex over the entire thing. This serializes against almost
12015 * everything that wants to access the ctx.
12017 * The exception is sys_perf_event_open() /
12018 * perf_event_create_kernel_count() which does find_get_context()
12019 * without ctx::mutex (it cannot because of the move_group double mutex
12020 * lock thing). See the comments in perf_install_in_context().
12022 mutex_lock(&child_ctx->mutex);
12025 * In a single ctx::lock section, de-schedule the events and detach the
12026 * context from the task such that we cannot ever get it scheduled back
12029 raw_spin_lock_irq(&child_ctx->lock);
12030 task_ctx_sched_out(__get_cpu_context(child_ctx), child_ctx, EVENT_ALL);
12033 * Now that the context is inactive, destroy the task <-> ctx relation
12034 * and mark the context dead.
12036 RCU_INIT_POINTER(child->perf_event_ctxp[ctxn], NULL);
12037 put_ctx(child_ctx); /* cannot be last */
12038 WRITE_ONCE(child_ctx->task, TASK_TOMBSTONE);
12039 put_task_struct(current); /* cannot be last */
12041 clone_ctx = unclone_ctx(child_ctx);
12042 raw_spin_unlock_irq(&child_ctx->lock);
12045 put_ctx(clone_ctx);
12048 * Report the task dead after unscheduling the events so that we
12049 * won't get any samples after PERF_RECORD_EXIT. We can however still
12050 * get a few PERF_RECORD_READ events.
12052 perf_event_task(child, child_ctx, 0);
12054 list_for_each_entry_safe(child_event, next, &child_ctx->event_list, event_entry)
12055 perf_event_exit_event(child_event, child_ctx, child);
12057 mutex_unlock(&child_ctx->mutex);
12059 put_ctx(child_ctx);
12063 * When a child task exits, feed back event values to parent events.
12065 * Can be called with exec_update_mutex held when called from
12066 * install_exec_creds().
12068 void perf_event_exit_task(struct task_struct *child)
12070 struct perf_event *event, *tmp;
12073 mutex_lock(&child->perf_event_mutex);
12074 list_for_each_entry_safe(event, tmp, &child->perf_event_list,
12076 list_del_init(&event->owner_entry);
12079 * Ensure the list deletion is visible before we clear
12080 * the owner, closes a race against perf_release() where
12081 * we need to serialize on the owner->perf_event_mutex.
12083 smp_store_release(&event->owner, NULL);
12085 mutex_unlock(&child->perf_event_mutex);
12087 for_each_task_context_nr(ctxn)
12088 perf_event_exit_task_context(child, ctxn);
12091 * The perf_event_exit_task_context calls perf_event_task
12092 * with child's task_ctx, which generates EXIT events for
12093 * child contexts and sets child->perf_event_ctxp[] to NULL.
12094 * At this point we need to send EXIT events to cpu contexts.
12096 perf_event_task(child, NULL, 0);
12099 static void perf_free_event(struct perf_event *event,
12100 struct perf_event_context *ctx)
12102 struct perf_event *parent = event->parent;
12104 if (WARN_ON_ONCE(!parent))
12107 mutex_lock(&parent->child_mutex);
12108 list_del_init(&event->child_list);
12109 mutex_unlock(&parent->child_mutex);
12113 raw_spin_lock_irq(&ctx->lock);
12114 perf_group_detach(event);
12115 list_del_event(event, ctx);
12116 raw_spin_unlock_irq(&ctx->lock);
12121 * Free a context as created by inheritance by perf_event_init_task() below,
12122 * used by fork() in case of fail.
12124 * Even though the task has never lived, the context and events have been
12125 * exposed through the child_list, so we must take care tearing it all down.
12127 void perf_event_free_task(struct task_struct *task)
12129 struct perf_event_context *ctx;
12130 struct perf_event *event, *tmp;
12133 for_each_task_context_nr(ctxn) {
12134 ctx = task->perf_event_ctxp[ctxn];
12138 mutex_lock(&ctx->mutex);
12139 raw_spin_lock_irq(&ctx->lock);
12141 * Destroy the task <-> ctx relation and mark the context dead.
12143 * This is important because even though the task hasn't been
12144 * exposed yet the context has been (through child_list).
12146 RCU_INIT_POINTER(task->perf_event_ctxp[ctxn], NULL);
12147 WRITE_ONCE(ctx->task, TASK_TOMBSTONE);
12148 put_task_struct(task); /* cannot be last */
12149 raw_spin_unlock_irq(&ctx->lock);
12151 list_for_each_entry_safe(event, tmp, &ctx->event_list, event_entry)
12152 perf_free_event(event, ctx);
12154 mutex_unlock(&ctx->mutex);
12157 * perf_event_release_kernel() could've stolen some of our
12158 * child events and still have them on its free_list. In that
12159 * case we must wait for these events to have been freed (in
12160 * particular all their references to this task must've been
12163 * Without this copy_process() will unconditionally free this
12164 * task (irrespective of its reference count) and
12165 * _free_event()'s put_task_struct(event->hw.target) will be a
12168 * Wait for all events to drop their context reference.
12170 wait_var_event(&ctx->refcount, refcount_read(&ctx->refcount) == 1);
12171 put_ctx(ctx); /* must be last */
12175 void perf_event_delayed_put(struct task_struct *task)
12179 for_each_task_context_nr(ctxn)
12180 WARN_ON_ONCE(task->perf_event_ctxp[ctxn]);
12183 struct file *perf_event_get(unsigned int fd)
12185 struct file *file = fget(fd);
12187 return ERR_PTR(-EBADF);
12189 if (file->f_op != &perf_fops) {
12191 return ERR_PTR(-EBADF);
12197 const struct perf_event *perf_get_event(struct file *file)
12199 if (file->f_op != &perf_fops)
12200 return ERR_PTR(-EINVAL);
12202 return file->private_data;
12205 const struct perf_event_attr *perf_event_attrs(struct perf_event *event)
12208 return ERR_PTR(-EINVAL);
12210 return &event->attr;
12214 * Inherit an event from parent task to child task.
12217 * - valid pointer on success
12218 * - NULL for orphaned events
12219 * - IS_ERR() on error
12221 static struct perf_event *
12222 inherit_event(struct perf_event *parent_event,
12223 struct task_struct *parent,
12224 struct perf_event_context *parent_ctx,
12225 struct task_struct *child,
12226 struct perf_event *group_leader,
12227 struct perf_event_context *child_ctx)
12229 enum perf_event_state parent_state = parent_event->state;
12230 struct perf_event *child_event;
12231 unsigned long flags;
12234 * Instead of creating recursive hierarchies of events,
12235 * we link inherited events back to the original parent,
12236 * which has a filp for sure, which we use as the reference
12239 if (parent_event->parent)
12240 parent_event = parent_event->parent;
12242 child_event = perf_event_alloc(&parent_event->attr,
12245 group_leader, parent_event,
12247 if (IS_ERR(child_event))
12248 return child_event;
12251 if ((child_event->attach_state & PERF_ATTACH_TASK_DATA) &&
12252 !child_ctx->task_ctx_data) {
12253 struct pmu *pmu = child_event->pmu;
12255 child_ctx->task_ctx_data = kzalloc(pmu->task_ctx_size,
12257 if (!child_ctx->task_ctx_data) {
12258 free_event(child_event);
12259 return ERR_PTR(-ENOMEM);
12264 * is_orphaned_event() and list_add_tail(&parent_event->child_list)
12265 * must be under the same lock in order to serialize against
12266 * perf_event_release_kernel(), such that either we must observe
12267 * is_orphaned_event() or they will observe us on the child_list.
12269 mutex_lock(&parent_event->child_mutex);
12270 if (is_orphaned_event(parent_event) ||
12271 !atomic_long_inc_not_zero(&parent_event->refcount)) {
12272 mutex_unlock(&parent_event->child_mutex);
12273 /* task_ctx_data is freed with child_ctx */
12274 free_event(child_event);
12278 get_ctx(child_ctx);
12281 * Make the child state follow the state of the parent event,
12282 * not its attr.disabled bit. We hold the parent's mutex,
12283 * so we won't race with perf_event_{en, dis}able_family.
12285 if (parent_state >= PERF_EVENT_STATE_INACTIVE)
12286 child_event->state = PERF_EVENT_STATE_INACTIVE;
12288 child_event->state = PERF_EVENT_STATE_OFF;
12290 if (parent_event->attr.freq) {
12291 u64 sample_period = parent_event->hw.sample_period;
12292 struct hw_perf_event *hwc = &child_event->hw;
12294 hwc->sample_period = sample_period;
12295 hwc->last_period = sample_period;
12297 local64_set(&hwc->period_left, sample_period);
12300 child_event->ctx = child_ctx;
12301 child_event->overflow_handler = parent_event->overflow_handler;
12302 child_event->overflow_handler_context
12303 = parent_event->overflow_handler_context;
12306 * Precalculate sample_data sizes
12308 perf_event__header_size(child_event);
12309 perf_event__id_header_size(child_event);
12312 * Link it up in the child's context:
12314 raw_spin_lock_irqsave(&child_ctx->lock, flags);
12315 add_event_to_ctx(child_event, child_ctx);
12316 raw_spin_unlock_irqrestore(&child_ctx->lock, flags);
12319 * Link this into the parent event's child list
12321 list_add_tail(&child_event->child_list, &parent_event->child_list);
12322 mutex_unlock(&parent_event->child_mutex);
12324 return child_event;
12328 * Inherits an event group.
12330 * This will quietly suppress orphaned events; !inherit_event() is not an error.
12331 * This matches with perf_event_release_kernel() removing all child events.
12337 static int inherit_group(struct perf_event *parent_event,
12338 struct task_struct *parent,
12339 struct perf_event_context *parent_ctx,
12340 struct task_struct *child,
12341 struct perf_event_context *child_ctx)
12343 struct perf_event *leader;
12344 struct perf_event *sub;
12345 struct perf_event *child_ctr;
12347 leader = inherit_event(parent_event, parent, parent_ctx,
12348 child, NULL, child_ctx);
12349 if (IS_ERR(leader))
12350 return PTR_ERR(leader);
12352 * @leader can be NULL here because of is_orphaned_event(). In this
12353 * case inherit_event() will create individual events, similar to what
12354 * perf_group_detach() would do anyway.
12356 for_each_sibling_event(sub, parent_event) {
12357 child_ctr = inherit_event(sub, parent, parent_ctx,
12358 child, leader, child_ctx);
12359 if (IS_ERR(child_ctr))
12360 return PTR_ERR(child_ctr);
12362 if (sub->aux_event == parent_event && child_ctr &&
12363 !perf_get_aux_event(child_ctr, leader))
12370 * Creates the child task context and tries to inherit the event-group.
12372 * Clears @inherited_all on !attr.inherited or error. Note that we'll leave
12373 * inherited_all set when we 'fail' to inherit an orphaned event; this is
12374 * consistent with perf_event_release_kernel() removing all child events.
12381 inherit_task_group(struct perf_event *event, struct task_struct *parent,
12382 struct perf_event_context *parent_ctx,
12383 struct task_struct *child, int ctxn,
12384 int *inherited_all)
12387 struct perf_event_context *child_ctx;
12389 if (!event->attr.inherit) {
12390 *inherited_all = 0;
12394 child_ctx = child->perf_event_ctxp[ctxn];
12397 * This is executed from the parent task context, so
12398 * inherit events that have been marked for cloning.
12399 * First allocate and initialize a context for the
12402 child_ctx = alloc_perf_context(parent_ctx->pmu, child);
12406 child->perf_event_ctxp[ctxn] = child_ctx;
12409 ret = inherit_group(event, parent, parent_ctx,
12413 *inherited_all = 0;
12419 * Initialize the perf_event context in task_struct
12421 static int perf_event_init_context(struct task_struct *child, int ctxn)
12423 struct perf_event_context *child_ctx, *parent_ctx;
12424 struct perf_event_context *cloned_ctx;
12425 struct perf_event *event;
12426 struct task_struct *parent = current;
12427 int inherited_all = 1;
12428 unsigned long flags;
12431 if (likely(!parent->perf_event_ctxp[ctxn]))
12435 * If the parent's context is a clone, pin it so it won't get
12436 * swapped under us.
12438 parent_ctx = perf_pin_task_context(parent, ctxn);
12443 * No need to check if parent_ctx != NULL here; since we saw
12444 * it non-NULL earlier, the only reason for it to become NULL
12445 * is if we exit, and since we're currently in the middle of
12446 * a fork we can't be exiting at the same time.
12450 * Lock the parent list. No need to lock the child - not PID
12451 * hashed yet and not running, so nobody can access it.
12453 mutex_lock(&parent_ctx->mutex);
12456 * We dont have to disable NMIs - we are only looking at
12457 * the list, not manipulating it:
12459 perf_event_groups_for_each(event, &parent_ctx->pinned_groups) {
12460 ret = inherit_task_group(event, parent, parent_ctx,
12461 child, ctxn, &inherited_all);
12467 * We can't hold ctx->lock when iterating the ->flexible_group list due
12468 * to allocations, but we need to prevent rotation because
12469 * rotate_ctx() will change the list from interrupt context.
12471 raw_spin_lock_irqsave(&parent_ctx->lock, flags);
12472 parent_ctx->rotate_disable = 1;
12473 raw_spin_unlock_irqrestore(&parent_ctx->lock, flags);
12475 perf_event_groups_for_each(event, &parent_ctx->flexible_groups) {
12476 ret = inherit_task_group(event, parent, parent_ctx,
12477 child, ctxn, &inherited_all);
12482 raw_spin_lock_irqsave(&parent_ctx->lock, flags);
12483 parent_ctx->rotate_disable = 0;
12485 child_ctx = child->perf_event_ctxp[ctxn];
12487 if (child_ctx && inherited_all) {
12489 * Mark the child context as a clone of the parent
12490 * context, or of whatever the parent is a clone of.
12492 * Note that if the parent is a clone, the holding of
12493 * parent_ctx->lock avoids it from being uncloned.
12495 cloned_ctx = parent_ctx->parent_ctx;
12497 child_ctx->parent_ctx = cloned_ctx;
12498 child_ctx->parent_gen = parent_ctx->parent_gen;
12500 child_ctx->parent_ctx = parent_ctx;
12501 child_ctx->parent_gen = parent_ctx->generation;
12503 get_ctx(child_ctx->parent_ctx);
12506 raw_spin_unlock_irqrestore(&parent_ctx->lock, flags);
12508 mutex_unlock(&parent_ctx->mutex);
12510 perf_unpin_context(parent_ctx);
12511 put_ctx(parent_ctx);
12517 * Initialize the perf_event context in task_struct
12519 int perf_event_init_task(struct task_struct *child)
12523 memset(child->perf_event_ctxp, 0, sizeof(child->perf_event_ctxp));
12524 mutex_init(&child->perf_event_mutex);
12525 INIT_LIST_HEAD(&child->perf_event_list);
12527 for_each_task_context_nr(ctxn) {
12528 ret = perf_event_init_context(child, ctxn);
12530 perf_event_free_task(child);
12538 static void __init perf_event_init_all_cpus(void)
12540 struct swevent_htable *swhash;
12543 zalloc_cpumask_var(&perf_online_mask, GFP_KERNEL);
12545 for_each_possible_cpu(cpu) {
12546 swhash = &per_cpu(swevent_htable, cpu);
12547 mutex_init(&swhash->hlist_mutex);
12548 INIT_LIST_HEAD(&per_cpu(active_ctx_list, cpu));
12550 INIT_LIST_HEAD(&per_cpu(pmu_sb_events.list, cpu));
12551 raw_spin_lock_init(&per_cpu(pmu_sb_events.lock, cpu));
12553 #ifdef CONFIG_CGROUP_PERF
12554 INIT_LIST_HEAD(&per_cpu(cgrp_cpuctx_list, cpu));
12556 INIT_LIST_HEAD(&per_cpu(sched_cb_list, cpu));
12560 static void perf_swevent_init_cpu(unsigned int cpu)
12562 struct swevent_htable *swhash = &per_cpu(swevent_htable, cpu);
12564 mutex_lock(&swhash->hlist_mutex);
12565 if (swhash->hlist_refcount > 0 && !swevent_hlist_deref(swhash)) {
12566 struct swevent_hlist *hlist;
12568 hlist = kzalloc_node(sizeof(*hlist), GFP_KERNEL, cpu_to_node(cpu));
12570 rcu_assign_pointer(swhash->swevent_hlist, hlist);
12572 mutex_unlock(&swhash->hlist_mutex);
12575 #if defined CONFIG_HOTPLUG_CPU || defined CONFIG_KEXEC_CORE
12576 static void __perf_event_exit_context(void *__info)
12578 struct perf_event_context *ctx = __info;
12579 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
12580 struct perf_event *event;
12582 raw_spin_lock(&ctx->lock);
12583 ctx_sched_out(ctx, cpuctx, EVENT_TIME);
12584 list_for_each_entry(event, &ctx->event_list, event_entry)
12585 __perf_remove_from_context(event, cpuctx, ctx, (void *)DETACH_GROUP);
12586 raw_spin_unlock(&ctx->lock);
12589 static void perf_event_exit_cpu_context(int cpu)
12591 struct perf_cpu_context *cpuctx;
12592 struct perf_event_context *ctx;
12595 mutex_lock(&pmus_lock);
12596 list_for_each_entry(pmu, &pmus, entry) {
12597 cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
12598 ctx = &cpuctx->ctx;
12600 mutex_lock(&ctx->mutex);
12601 smp_call_function_single(cpu, __perf_event_exit_context, ctx, 1);
12602 cpuctx->online = 0;
12603 mutex_unlock(&ctx->mutex);
12605 cpumask_clear_cpu(cpu, perf_online_mask);
12606 mutex_unlock(&pmus_lock);
12610 static void perf_event_exit_cpu_context(int cpu) { }
12614 int perf_event_init_cpu(unsigned int cpu)
12616 struct perf_cpu_context *cpuctx;
12617 struct perf_event_context *ctx;
12620 perf_swevent_init_cpu(cpu);
12622 mutex_lock(&pmus_lock);
12623 cpumask_set_cpu(cpu, perf_online_mask);
12624 list_for_each_entry(pmu, &pmus, entry) {
12625 cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
12626 ctx = &cpuctx->ctx;
12628 mutex_lock(&ctx->mutex);
12629 cpuctx->online = 1;
12630 mutex_unlock(&ctx->mutex);
12632 mutex_unlock(&pmus_lock);
12637 int perf_event_exit_cpu(unsigned int cpu)
12639 perf_event_exit_cpu_context(cpu);
12644 perf_reboot(struct notifier_block *notifier, unsigned long val, void *v)
12648 for_each_online_cpu(cpu)
12649 perf_event_exit_cpu(cpu);
12655 * Run the perf reboot notifier at the very last possible moment so that
12656 * the generic watchdog code runs as long as possible.
12658 static struct notifier_block perf_reboot_notifier = {
12659 .notifier_call = perf_reboot,
12660 .priority = INT_MIN,
12663 void __init perf_event_init(void)
12667 idr_init(&pmu_idr);
12669 perf_event_init_all_cpus();
12670 init_srcu_struct(&pmus_srcu);
12671 perf_pmu_register(&perf_swevent, "software", PERF_TYPE_SOFTWARE);
12672 perf_pmu_register(&perf_cpu_clock, NULL, -1);
12673 perf_pmu_register(&perf_task_clock, NULL, -1);
12674 perf_tp_register();
12675 perf_event_init_cpu(smp_processor_id());
12676 register_reboot_notifier(&perf_reboot_notifier);
12678 ret = init_hw_breakpoint();
12679 WARN(ret, "hw_breakpoint initialization failed with: %d", ret);
12682 * Build time assertion that we keep the data_head at the intended
12683 * location. IOW, validation we got the __reserved[] size right.
12685 BUILD_BUG_ON((offsetof(struct perf_event_mmap_page, data_head))
12689 ssize_t perf_event_sysfs_show(struct device *dev, struct device_attribute *attr,
12692 struct perf_pmu_events_attr *pmu_attr =
12693 container_of(attr, struct perf_pmu_events_attr, attr);
12695 if (pmu_attr->event_str)
12696 return sprintf(page, "%s\n", pmu_attr->event_str);
12700 EXPORT_SYMBOL_GPL(perf_event_sysfs_show);
12702 static int __init perf_event_sysfs_init(void)
12707 mutex_lock(&pmus_lock);
12709 ret = bus_register(&pmu_bus);
12713 list_for_each_entry(pmu, &pmus, entry) {
12714 if (!pmu->name || pmu->type < 0)
12717 ret = pmu_dev_alloc(pmu);
12718 WARN(ret, "Failed to register pmu: %s, reason %d\n", pmu->name, ret);
12720 pmu_bus_running = 1;
12724 mutex_unlock(&pmus_lock);
12728 device_initcall(perf_event_sysfs_init);
12730 #ifdef CONFIG_CGROUP_PERF
12731 static struct cgroup_subsys_state *
12732 perf_cgroup_css_alloc(struct cgroup_subsys_state *parent_css)
12734 struct perf_cgroup *jc;
12736 jc = kzalloc(sizeof(*jc), GFP_KERNEL);
12738 return ERR_PTR(-ENOMEM);
12740 jc->info = alloc_percpu(struct perf_cgroup_info);
12743 return ERR_PTR(-ENOMEM);
12749 static void perf_cgroup_css_free(struct cgroup_subsys_state *css)
12751 struct perf_cgroup *jc = container_of(css, struct perf_cgroup, css);
12753 free_percpu(jc->info);
12757 static int __perf_cgroup_move(void *info)
12759 struct task_struct *task = info;
12761 perf_cgroup_switch(task, PERF_CGROUP_SWOUT | PERF_CGROUP_SWIN);
12766 static void perf_cgroup_attach(struct cgroup_taskset *tset)
12768 struct task_struct *task;
12769 struct cgroup_subsys_state *css;
12771 cgroup_taskset_for_each(task, css, tset)
12772 task_function_call(task, __perf_cgroup_move, task);
12775 struct cgroup_subsys perf_event_cgrp_subsys = {
12776 .css_alloc = perf_cgroup_css_alloc,
12777 .css_free = perf_cgroup_css_free,
12778 .attach = perf_cgroup_attach,
12780 * Implicitly enable on dfl hierarchy so that perf events can
12781 * always be filtered by cgroup2 path as long as perf_event
12782 * controller is not mounted on a legacy hierarchy.
12784 .implicit_on_dfl = true,
12787 #endif /* CONFIG_CGROUP_PERF */