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/hugetlb.h>
32 #include <linux/rculist.h>
33 #include <linux/uaccess.h>
34 #include <linux/syscalls.h>
35 #include <linux/anon_inodes.h>
36 #include <linux/kernel_stat.h>
37 #include <linux/cgroup.h>
38 #include <linux/perf_event.h>
39 #include <linux/trace_events.h>
40 #include <linux/hw_breakpoint.h>
41 #include <linux/mm_types.h>
42 #include <linux/module.h>
43 #include <linux/mman.h>
44 #include <linux/compat.h>
45 #include <linux/bpf.h>
46 #include <linux/filter.h>
47 #include <linux/namei.h>
48 #include <linux/parser.h>
49 #include <linux/sched/clock.h>
50 #include <linux/sched/mm.h>
51 #include <linux/proc_ns.h>
52 #include <linux/mount.h>
53 #include <linux/min_heap.h>
54 #include <linux/highmem.h>
55 #include <linux/pgtable.h>
56 #include <linux/buildid.h>
60 #include <asm/irq_regs.h>
62 typedef int (*remote_function_f)(void *);
64 struct remote_function_call {
65 struct task_struct *p;
66 remote_function_f func;
71 static void remote_function(void *data)
73 struct remote_function_call *tfc = data;
74 struct task_struct *p = tfc->p;
78 if (task_cpu(p) != smp_processor_id())
82 * Now that we're on right CPU with IRQs disabled, we can test
83 * if we hit the right task without races.
86 tfc->ret = -ESRCH; /* No such (running) process */
91 tfc->ret = tfc->func(tfc->info);
95 * task_function_call - call a function on the cpu on which a task runs
96 * @p: the task to evaluate
97 * @func: the function to be called
98 * @info: the function call argument
100 * Calls the function @func when the task is currently running. This might
101 * be on the current CPU, which just calls the function directly. This will
102 * retry due to any failures in smp_call_function_single(), such as if the
103 * task_cpu() goes offline concurrently.
105 * returns @func return value or -ESRCH or -ENXIO when the process isn't running
108 task_function_call(struct task_struct *p, remote_function_f func, void *info)
110 struct remote_function_call data = {
119 ret = smp_call_function_single(task_cpu(p), remote_function,
134 * cpu_function_call - call a function on the cpu
135 * @cpu: target cpu to queue this function
136 * @func: the function to be called
137 * @info: the function call argument
139 * Calls the function @func on the remote cpu.
141 * returns: @func return value or -ENXIO when the cpu is offline
143 static int cpu_function_call(int cpu, remote_function_f func, void *info)
145 struct remote_function_call data = {
149 .ret = -ENXIO, /* No such CPU */
152 smp_call_function_single(cpu, remote_function, &data, 1);
157 static inline struct perf_cpu_context *
158 __get_cpu_context(struct perf_event_context *ctx)
160 return this_cpu_ptr(ctx->pmu->pmu_cpu_context);
163 static void perf_ctx_lock(struct perf_cpu_context *cpuctx,
164 struct perf_event_context *ctx)
166 raw_spin_lock(&cpuctx->ctx.lock);
168 raw_spin_lock(&ctx->lock);
171 static void perf_ctx_unlock(struct perf_cpu_context *cpuctx,
172 struct perf_event_context *ctx)
175 raw_spin_unlock(&ctx->lock);
176 raw_spin_unlock(&cpuctx->ctx.lock);
179 #define TASK_TOMBSTONE ((void *)-1L)
181 static bool is_kernel_event(struct perf_event *event)
183 return READ_ONCE(event->owner) == TASK_TOMBSTONE;
187 * On task ctx scheduling...
189 * When !ctx->nr_events a task context will not be scheduled. This means
190 * we can disable the scheduler hooks (for performance) without leaving
191 * pending task ctx state.
193 * This however results in two special cases:
195 * - removing the last event from a task ctx; this is relatively straight
196 * forward and is done in __perf_remove_from_context.
198 * - adding the first event to a task ctx; this is tricky because we cannot
199 * rely on ctx->is_active and therefore cannot use event_function_call().
200 * See perf_install_in_context().
202 * If ctx->nr_events, then ctx->is_active and cpuctx->task_ctx are set.
205 typedef void (*event_f)(struct perf_event *, struct perf_cpu_context *,
206 struct perf_event_context *, void *);
208 struct event_function_struct {
209 struct perf_event *event;
214 static int event_function(void *info)
216 struct event_function_struct *efs = info;
217 struct perf_event *event = efs->event;
218 struct perf_event_context *ctx = event->ctx;
219 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
220 struct perf_event_context *task_ctx = cpuctx->task_ctx;
223 lockdep_assert_irqs_disabled();
225 perf_ctx_lock(cpuctx, task_ctx);
227 * Since we do the IPI call without holding ctx->lock things can have
228 * changed, double check we hit the task we set out to hit.
231 if (ctx->task != current) {
237 * We only use event_function_call() on established contexts,
238 * and event_function() is only ever called when active (or
239 * rather, we'll have bailed in task_function_call() or the
240 * above ctx->task != current test), therefore we must have
241 * ctx->is_active here.
243 WARN_ON_ONCE(!ctx->is_active);
245 * And since we have ctx->is_active, cpuctx->task_ctx must
248 WARN_ON_ONCE(task_ctx != ctx);
250 WARN_ON_ONCE(&cpuctx->ctx != ctx);
253 efs->func(event, cpuctx, ctx, efs->data);
255 perf_ctx_unlock(cpuctx, task_ctx);
260 static void event_function_call(struct perf_event *event, event_f func, void *data)
262 struct perf_event_context *ctx = event->ctx;
263 struct task_struct *task = READ_ONCE(ctx->task); /* verified in event_function */
264 struct event_function_struct efs = {
270 if (!event->parent) {
272 * If this is a !child event, we must hold ctx::mutex to
273 * stabilize the event->ctx relation. See
274 * perf_event_ctx_lock().
276 lockdep_assert_held(&ctx->mutex);
280 cpu_function_call(event->cpu, event_function, &efs);
284 if (task == TASK_TOMBSTONE)
288 if (!task_function_call(task, event_function, &efs))
291 raw_spin_lock_irq(&ctx->lock);
293 * Reload the task pointer, it might have been changed by
294 * a concurrent perf_event_context_sched_out().
297 if (task == TASK_TOMBSTONE) {
298 raw_spin_unlock_irq(&ctx->lock);
301 if (ctx->is_active) {
302 raw_spin_unlock_irq(&ctx->lock);
305 func(event, NULL, ctx, data);
306 raw_spin_unlock_irq(&ctx->lock);
310 * Similar to event_function_call() + event_function(), but hard assumes IRQs
311 * are already disabled and we're on the right CPU.
313 static void event_function_local(struct perf_event *event, event_f func, void *data)
315 struct perf_event_context *ctx = event->ctx;
316 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
317 struct task_struct *task = READ_ONCE(ctx->task);
318 struct perf_event_context *task_ctx = NULL;
320 lockdep_assert_irqs_disabled();
323 if (task == TASK_TOMBSTONE)
329 perf_ctx_lock(cpuctx, task_ctx);
332 if (task == TASK_TOMBSTONE)
337 * We must be either inactive or active and the right task,
338 * otherwise we're screwed, since we cannot IPI to somewhere
341 if (ctx->is_active) {
342 if (WARN_ON_ONCE(task != current))
345 if (WARN_ON_ONCE(cpuctx->task_ctx != ctx))
349 WARN_ON_ONCE(&cpuctx->ctx != ctx);
352 func(event, cpuctx, ctx, data);
354 perf_ctx_unlock(cpuctx, task_ctx);
357 #define PERF_FLAG_ALL (PERF_FLAG_FD_NO_GROUP |\
358 PERF_FLAG_FD_OUTPUT |\
359 PERF_FLAG_PID_CGROUP |\
360 PERF_FLAG_FD_CLOEXEC)
363 * branch priv levels that need permission checks
365 #define PERF_SAMPLE_BRANCH_PERM_PLM \
366 (PERF_SAMPLE_BRANCH_KERNEL |\
367 PERF_SAMPLE_BRANCH_HV)
370 EVENT_FLEXIBLE = 0x1,
373 /* see ctx_resched() for details */
375 EVENT_ALL = EVENT_FLEXIBLE | EVENT_PINNED,
379 * perf_sched_events : >0 events exist
380 * perf_cgroup_events: >0 per-cpu cgroup events exist on this cpu
383 static void perf_sched_delayed(struct work_struct *work);
384 DEFINE_STATIC_KEY_FALSE(perf_sched_events);
385 static DECLARE_DELAYED_WORK(perf_sched_work, perf_sched_delayed);
386 static DEFINE_MUTEX(perf_sched_mutex);
387 static atomic_t perf_sched_count;
389 static DEFINE_PER_CPU(atomic_t, perf_cgroup_events);
390 static DEFINE_PER_CPU(int, perf_sched_cb_usages);
391 static DEFINE_PER_CPU(struct pmu_event_list, pmu_sb_events);
393 static atomic_t nr_mmap_events __read_mostly;
394 static atomic_t nr_comm_events __read_mostly;
395 static atomic_t nr_namespaces_events __read_mostly;
396 static atomic_t nr_task_events __read_mostly;
397 static atomic_t nr_freq_events __read_mostly;
398 static atomic_t nr_switch_events __read_mostly;
399 static atomic_t nr_ksymbol_events __read_mostly;
400 static atomic_t nr_bpf_events __read_mostly;
401 static atomic_t nr_cgroup_events __read_mostly;
402 static atomic_t nr_text_poke_events __read_mostly;
403 static atomic_t nr_build_id_events __read_mostly;
405 static LIST_HEAD(pmus);
406 static DEFINE_MUTEX(pmus_lock);
407 static struct srcu_struct pmus_srcu;
408 static cpumask_var_t perf_online_mask;
409 static struct kmem_cache *perf_event_cache;
412 * perf event paranoia level:
413 * -1 - not paranoid at all
414 * 0 - disallow raw tracepoint access for unpriv
415 * 1 - disallow cpu events for unpriv
416 * 2 - disallow kernel profiling for unpriv
418 int sysctl_perf_event_paranoid __read_mostly = 2;
420 /* Minimum for 512 kiB + 1 user control page */
421 int sysctl_perf_event_mlock __read_mostly = 512 + (PAGE_SIZE / 1024); /* 'free' kiB per user */
424 * max perf event sample rate
426 #define DEFAULT_MAX_SAMPLE_RATE 100000
427 #define DEFAULT_SAMPLE_PERIOD_NS (NSEC_PER_SEC / DEFAULT_MAX_SAMPLE_RATE)
428 #define DEFAULT_CPU_TIME_MAX_PERCENT 25
430 int sysctl_perf_event_sample_rate __read_mostly = DEFAULT_MAX_SAMPLE_RATE;
432 static int max_samples_per_tick __read_mostly = DIV_ROUND_UP(DEFAULT_MAX_SAMPLE_RATE, HZ);
433 static int perf_sample_period_ns __read_mostly = DEFAULT_SAMPLE_PERIOD_NS;
435 static int perf_sample_allowed_ns __read_mostly =
436 DEFAULT_SAMPLE_PERIOD_NS * DEFAULT_CPU_TIME_MAX_PERCENT / 100;
438 static void update_perf_cpu_limits(void)
440 u64 tmp = perf_sample_period_ns;
442 tmp *= sysctl_perf_cpu_time_max_percent;
443 tmp = div_u64(tmp, 100);
447 WRITE_ONCE(perf_sample_allowed_ns, tmp);
450 static bool perf_rotate_context(struct perf_cpu_context *cpuctx);
452 int perf_proc_update_handler(struct ctl_table *table, int write,
453 void *buffer, size_t *lenp, loff_t *ppos)
456 int perf_cpu = sysctl_perf_cpu_time_max_percent;
458 * If throttling is disabled don't allow the write:
460 if (write && (perf_cpu == 100 || perf_cpu == 0))
463 ret = proc_dointvec_minmax(table, write, buffer, lenp, ppos);
467 max_samples_per_tick = DIV_ROUND_UP(sysctl_perf_event_sample_rate, HZ);
468 perf_sample_period_ns = NSEC_PER_SEC / sysctl_perf_event_sample_rate;
469 update_perf_cpu_limits();
474 int sysctl_perf_cpu_time_max_percent __read_mostly = DEFAULT_CPU_TIME_MAX_PERCENT;
476 int perf_cpu_time_max_percent_handler(struct ctl_table *table, int write,
477 void *buffer, size_t *lenp, loff_t *ppos)
479 int ret = proc_dointvec_minmax(table, write, buffer, lenp, ppos);
484 if (sysctl_perf_cpu_time_max_percent == 100 ||
485 sysctl_perf_cpu_time_max_percent == 0) {
487 "perf: Dynamic interrupt throttling disabled, can hang your system!\n");
488 WRITE_ONCE(perf_sample_allowed_ns, 0);
490 update_perf_cpu_limits();
497 * perf samples are done in some very critical code paths (NMIs).
498 * If they take too much CPU time, the system can lock up and not
499 * get any real work done. This will drop the sample rate when
500 * we detect that events are taking too long.
502 #define NR_ACCUMULATED_SAMPLES 128
503 static DEFINE_PER_CPU(u64, running_sample_length);
505 static u64 __report_avg;
506 static u64 __report_allowed;
508 static void perf_duration_warn(struct irq_work *w)
510 printk_ratelimited(KERN_INFO
511 "perf: interrupt took too long (%lld > %lld), lowering "
512 "kernel.perf_event_max_sample_rate to %d\n",
513 __report_avg, __report_allowed,
514 sysctl_perf_event_sample_rate);
517 static DEFINE_IRQ_WORK(perf_duration_work, perf_duration_warn);
519 void perf_sample_event_took(u64 sample_len_ns)
521 u64 max_len = READ_ONCE(perf_sample_allowed_ns);
529 /* Decay the counter by 1 average sample. */
530 running_len = __this_cpu_read(running_sample_length);
531 running_len -= running_len/NR_ACCUMULATED_SAMPLES;
532 running_len += sample_len_ns;
533 __this_cpu_write(running_sample_length, running_len);
536 * Note: this will be biased artifically low until we have
537 * seen NR_ACCUMULATED_SAMPLES. Doing it this way keeps us
538 * from having to maintain a count.
540 avg_len = running_len/NR_ACCUMULATED_SAMPLES;
541 if (avg_len <= max_len)
544 __report_avg = avg_len;
545 __report_allowed = max_len;
548 * Compute a throttle threshold 25% below the current duration.
550 avg_len += avg_len / 4;
551 max = (TICK_NSEC / 100) * sysctl_perf_cpu_time_max_percent;
557 WRITE_ONCE(perf_sample_allowed_ns, avg_len);
558 WRITE_ONCE(max_samples_per_tick, max);
560 sysctl_perf_event_sample_rate = max * HZ;
561 perf_sample_period_ns = NSEC_PER_SEC / sysctl_perf_event_sample_rate;
563 if (!irq_work_queue(&perf_duration_work)) {
564 early_printk("perf: interrupt took too long (%lld > %lld), lowering "
565 "kernel.perf_event_max_sample_rate to %d\n",
566 __report_avg, __report_allowed,
567 sysctl_perf_event_sample_rate);
571 static atomic64_t perf_event_id;
573 static void cpu_ctx_sched_out(struct perf_cpu_context *cpuctx,
574 enum event_type_t event_type);
576 static void cpu_ctx_sched_in(struct perf_cpu_context *cpuctx,
577 enum event_type_t event_type,
578 struct task_struct *task);
580 static void update_context_time(struct perf_event_context *ctx);
581 static u64 perf_event_time(struct perf_event *event);
583 void __weak perf_event_print_debug(void) { }
585 static inline u64 perf_clock(void)
587 return local_clock();
590 static inline u64 perf_event_clock(struct perf_event *event)
592 return event->clock();
596 * State based event timekeeping...
598 * The basic idea is to use event->state to determine which (if any) time
599 * fields to increment with the current delta. This means we only need to
600 * update timestamps when we change state or when they are explicitly requested
603 * Event groups make things a little more complicated, but not terribly so. The
604 * rules for a group are that if the group leader is OFF the entire group is
605 * OFF, irrespecive of what the group member states are. This results in
606 * __perf_effective_state().
608 * A futher ramification is that when a group leader flips between OFF and
609 * !OFF, we need to update all group member times.
612 * NOTE: perf_event_time() is based on the (cgroup) context time, and thus we
613 * need to make sure the relevant context time is updated before we try and
614 * update our timestamps.
617 static __always_inline enum perf_event_state
618 __perf_effective_state(struct perf_event *event)
620 struct perf_event *leader = event->group_leader;
622 if (leader->state <= PERF_EVENT_STATE_OFF)
623 return leader->state;
628 static __always_inline void
629 __perf_update_times(struct perf_event *event, u64 now, u64 *enabled, u64 *running)
631 enum perf_event_state state = __perf_effective_state(event);
632 u64 delta = now - event->tstamp;
634 *enabled = event->total_time_enabled;
635 if (state >= PERF_EVENT_STATE_INACTIVE)
638 *running = event->total_time_running;
639 if (state >= PERF_EVENT_STATE_ACTIVE)
643 static void perf_event_update_time(struct perf_event *event)
645 u64 now = perf_event_time(event);
647 __perf_update_times(event, now, &event->total_time_enabled,
648 &event->total_time_running);
652 static void perf_event_update_sibling_time(struct perf_event *leader)
654 struct perf_event *sibling;
656 for_each_sibling_event(sibling, leader)
657 perf_event_update_time(sibling);
661 perf_event_set_state(struct perf_event *event, enum perf_event_state state)
663 if (event->state == state)
666 perf_event_update_time(event);
668 * If a group leader gets enabled/disabled all its siblings
671 if ((event->state < 0) ^ (state < 0))
672 perf_event_update_sibling_time(event);
674 WRITE_ONCE(event->state, state);
677 #ifdef CONFIG_CGROUP_PERF
680 perf_cgroup_match(struct perf_event *event)
682 struct perf_event_context *ctx = event->ctx;
683 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
685 /* @event doesn't care about cgroup */
689 /* wants specific cgroup scope but @cpuctx isn't associated with any */
694 * Cgroup scoping is recursive. An event enabled for a cgroup is
695 * also enabled for all its descendant cgroups. If @cpuctx's
696 * cgroup is a descendant of @event's (the test covers identity
697 * case), it's a match.
699 return cgroup_is_descendant(cpuctx->cgrp->css.cgroup,
700 event->cgrp->css.cgroup);
703 static inline void perf_detach_cgroup(struct perf_event *event)
705 css_put(&event->cgrp->css);
709 static inline int is_cgroup_event(struct perf_event *event)
711 return event->cgrp != NULL;
714 static inline u64 perf_cgroup_event_time(struct perf_event *event)
716 struct perf_cgroup_info *t;
718 t = per_cpu_ptr(event->cgrp->info, event->cpu);
722 static inline void __update_cgrp_time(struct perf_cgroup *cgrp)
724 struct perf_cgroup_info *info;
729 info = this_cpu_ptr(cgrp->info);
731 info->time += now - info->timestamp;
732 info->timestamp = now;
735 static inline void update_cgrp_time_from_cpuctx(struct perf_cpu_context *cpuctx)
737 struct perf_cgroup *cgrp = cpuctx->cgrp;
738 struct cgroup_subsys_state *css;
741 for (css = &cgrp->css; css; css = css->parent) {
742 cgrp = container_of(css, struct perf_cgroup, css);
743 __update_cgrp_time(cgrp);
748 static inline void update_cgrp_time_from_event(struct perf_event *event)
750 struct perf_cgroup *cgrp;
753 * ensure we access cgroup data only when needed and
754 * when we know the cgroup is pinned (css_get)
756 if (!is_cgroup_event(event))
759 cgrp = perf_cgroup_from_task(current, event->ctx);
761 * Do not update time when cgroup is not active
763 if (cgroup_is_descendant(cgrp->css.cgroup, event->cgrp->css.cgroup))
764 __update_cgrp_time(event->cgrp);
768 perf_cgroup_set_timestamp(struct task_struct *task,
769 struct perf_event_context *ctx)
771 struct perf_cgroup *cgrp;
772 struct perf_cgroup_info *info;
773 struct cgroup_subsys_state *css;
776 * ctx->lock held by caller
777 * ensure we do not access cgroup data
778 * unless we have the cgroup pinned (css_get)
780 if (!task || !ctx->nr_cgroups)
783 cgrp = perf_cgroup_from_task(task, ctx);
785 for (css = &cgrp->css; css; css = css->parent) {
786 cgrp = container_of(css, struct perf_cgroup, css);
787 info = this_cpu_ptr(cgrp->info);
788 info->timestamp = ctx->timestamp;
792 static DEFINE_PER_CPU(struct list_head, cgrp_cpuctx_list);
794 #define PERF_CGROUP_SWOUT 0x1 /* cgroup switch out every event */
795 #define PERF_CGROUP_SWIN 0x2 /* cgroup switch in events based on task */
798 * reschedule events based on the cgroup constraint of task.
800 * mode SWOUT : schedule out everything
801 * mode SWIN : schedule in based on cgroup for next
803 static void perf_cgroup_switch(struct task_struct *task, int mode)
805 struct perf_cpu_context *cpuctx;
806 struct list_head *list;
810 * Disable interrupts and preemption to avoid this CPU's
811 * cgrp_cpuctx_entry to change under us.
813 local_irq_save(flags);
815 list = this_cpu_ptr(&cgrp_cpuctx_list);
816 list_for_each_entry(cpuctx, list, cgrp_cpuctx_entry) {
817 WARN_ON_ONCE(cpuctx->ctx.nr_cgroups == 0);
819 perf_ctx_lock(cpuctx, cpuctx->task_ctx);
820 perf_pmu_disable(cpuctx->ctx.pmu);
822 if (mode & PERF_CGROUP_SWOUT) {
823 cpu_ctx_sched_out(cpuctx, EVENT_ALL);
825 * must not be done before ctxswout due
826 * to event_filter_match() in event_sched_out()
831 if (mode & PERF_CGROUP_SWIN) {
832 WARN_ON_ONCE(cpuctx->cgrp);
834 * set cgrp before ctxsw in to allow
835 * event_filter_match() to not have to pass
837 * we pass the cpuctx->ctx to perf_cgroup_from_task()
838 * because cgorup events are only per-cpu
840 cpuctx->cgrp = perf_cgroup_from_task(task,
842 cpu_ctx_sched_in(cpuctx, EVENT_ALL, task);
844 perf_pmu_enable(cpuctx->ctx.pmu);
845 perf_ctx_unlock(cpuctx, cpuctx->task_ctx);
848 local_irq_restore(flags);
851 static inline void perf_cgroup_sched_out(struct task_struct *task,
852 struct task_struct *next)
854 struct perf_cgroup *cgrp1;
855 struct perf_cgroup *cgrp2 = NULL;
859 * we come here when we know perf_cgroup_events > 0
860 * we do not need to pass the ctx here because we know
861 * we are holding the rcu lock
863 cgrp1 = perf_cgroup_from_task(task, NULL);
864 cgrp2 = perf_cgroup_from_task(next, NULL);
867 * only schedule out current cgroup events if we know
868 * that we are switching to a different cgroup. Otherwise,
869 * do no touch the cgroup events.
872 perf_cgroup_switch(task, PERF_CGROUP_SWOUT);
877 static inline void perf_cgroup_sched_in(struct task_struct *prev,
878 struct task_struct *task)
880 struct perf_cgroup *cgrp1;
881 struct perf_cgroup *cgrp2 = NULL;
885 * we come here when we know perf_cgroup_events > 0
886 * we do not need to pass the ctx here because we know
887 * we are holding the rcu lock
889 cgrp1 = perf_cgroup_from_task(task, NULL);
890 cgrp2 = perf_cgroup_from_task(prev, NULL);
893 * only need to schedule in cgroup events if we are changing
894 * cgroup during ctxsw. Cgroup events were not scheduled
895 * out of ctxsw out if that was not the case.
898 perf_cgroup_switch(task, PERF_CGROUP_SWIN);
903 static int perf_cgroup_ensure_storage(struct perf_event *event,
904 struct cgroup_subsys_state *css)
906 struct perf_cpu_context *cpuctx;
907 struct perf_event **storage;
908 int cpu, heap_size, ret = 0;
911 * Allow storage to have sufficent space for an iterator for each
912 * possibly nested cgroup plus an iterator for events with no cgroup.
914 for (heap_size = 1; css; css = css->parent)
917 for_each_possible_cpu(cpu) {
918 cpuctx = per_cpu_ptr(event->pmu->pmu_cpu_context, cpu);
919 if (heap_size <= cpuctx->heap_size)
922 storage = kmalloc_node(heap_size * sizeof(struct perf_event *),
923 GFP_KERNEL, cpu_to_node(cpu));
929 raw_spin_lock_irq(&cpuctx->ctx.lock);
930 if (cpuctx->heap_size < heap_size) {
931 swap(cpuctx->heap, storage);
932 if (storage == cpuctx->heap_default)
934 cpuctx->heap_size = heap_size;
936 raw_spin_unlock_irq(&cpuctx->ctx.lock);
944 static inline int perf_cgroup_connect(int fd, struct perf_event *event,
945 struct perf_event_attr *attr,
946 struct perf_event *group_leader)
948 struct perf_cgroup *cgrp;
949 struct cgroup_subsys_state *css;
950 struct fd f = fdget(fd);
956 css = css_tryget_online_from_dir(f.file->f_path.dentry,
957 &perf_event_cgrp_subsys);
963 ret = perf_cgroup_ensure_storage(event, css);
967 cgrp = container_of(css, struct perf_cgroup, css);
971 * all events in a group must monitor
972 * the same cgroup because a task belongs
973 * to only one perf cgroup at a time
975 if (group_leader && group_leader->cgrp != cgrp) {
976 perf_detach_cgroup(event);
985 perf_cgroup_set_shadow_time(struct perf_event *event, u64 now)
987 struct perf_cgroup_info *t;
988 t = per_cpu_ptr(event->cgrp->info, event->cpu);
989 event->shadow_ctx_time = now - t->timestamp;
993 perf_cgroup_event_enable(struct perf_event *event, struct perf_event_context *ctx)
995 struct perf_cpu_context *cpuctx;
997 if (!is_cgroup_event(event))
1001 * Because cgroup events are always per-cpu events,
1002 * @ctx == &cpuctx->ctx.
1004 cpuctx = container_of(ctx, struct perf_cpu_context, ctx);
1007 * Since setting cpuctx->cgrp is conditional on the current @cgrp
1008 * matching the event's cgroup, we must do this for every new event,
1009 * because if the first would mismatch, the second would not try again
1010 * and we would leave cpuctx->cgrp unset.
1012 if (ctx->is_active && !cpuctx->cgrp) {
1013 struct perf_cgroup *cgrp = perf_cgroup_from_task(current, ctx);
1015 if (cgroup_is_descendant(cgrp->css.cgroup, event->cgrp->css.cgroup))
1016 cpuctx->cgrp = cgrp;
1019 if (ctx->nr_cgroups++)
1022 list_add(&cpuctx->cgrp_cpuctx_entry,
1023 per_cpu_ptr(&cgrp_cpuctx_list, event->cpu));
1027 perf_cgroup_event_disable(struct perf_event *event, struct perf_event_context *ctx)
1029 struct perf_cpu_context *cpuctx;
1031 if (!is_cgroup_event(event))
1035 * Because cgroup events are always per-cpu events,
1036 * @ctx == &cpuctx->ctx.
1038 cpuctx = container_of(ctx, struct perf_cpu_context, ctx);
1040 if (--ctx->nr_cgroups)
1043 if (ctx->is_active && cpuctx->cgrp)
1044 cpuctx->cgrp = NULL;
1046 list_del(&cpuctx->cgrp_cpuctx_entry);
1049 #else /* !CONFIG_CGROUP_PERF */
1052 perf_cgroup_match(struct perf_event *event)
1057 static inline void perf_detach_cgroup(struct perf_event *event)
1060 static inline int is_cgroup_event(struct perf_event *event)
1065 static inline void update_cgrp_time_from_event(struct perf_event *event)
1069 static inline void update_cgrp_time_from_cpuctx(struct perf_cpu_context *cpuctx)
1073 static inline void perf_cgroup_sched_out(struct task_struct *task,
1074 struct task_struct *next)
1078 static inline void perf_cgroup_sched_in(struct task_struct *prev,
1079 struct task_struct *task)
1083 static inline int perf_cgroup_connect(pid_t pid, struct perf_event *event,
1084 struct perf_event_attr *attr,
1085 struct perf_event *group_leader)
1091 perf_cgroup_set_timestamp(struct task_struct *task,
1092 struct perf_event_context *ctx)
1097 perf_cgroup_switch(struct task_struct *task, struct task_struct *next)
1102 perf_cgroup_set_shadow_time(struct perf_event *event, u64 now)
1106 static inline u64 perf_cgroup_event_time(struct perf_event *event)
1112 perf_cgroup_event_enable(struct perf_event *event, struct perf_event_context *ctx)
1117 perf_cgroup_event_disable(struct perf_event *event, struct perf_event_context *ctx)
1123 * set default to be dependent on timer tick just
1124 * like original code
1126 #define PERF_CPU_HRTIMER (1000 / HZ)
1128 * function must be called with interrupts disabled
1130 static enum hrtimer_restart perf_mux_hrtimer_handler(struct hrtimer *hr)
1132 struct perf_cpu_context *cpuctx;
1135 lockdep_assert_irqs_disabled();
1137 cpuctx = container_of(hr, struct perf_cpu_context, hrtimer);
1138 rotations = perf_rotate_context(cpuctx);
1140 raw_spin_lock(&cpuctx->hrtimer_lock);
1142 hrtimer_forward_now(hr, cpuctx->hrtimer_interval);
1144 cpuctx->hrtimer_active = 0;
1145 raw_spin_unlock(&cpuctx->hrtimer_lock);
1147 return rotations ? HRTIMER_RESTART : HRTIMER_NORESTART;
1150 static void __perf_mux_hrtimer_init(struct perf_cpu_context *cpuctx, int cpu)
1152 struct hrtimer *timer = &cpuctx->hrtimer;
1153 struct pmu *pmu = cpuctx->ctx.pmu;
1156 /* no multiplexing needed for SW PMU */
1157 if (pmu->task_ctx_nr == perf_sw_context)
1161 * check default is sane, if not set then force to
1162 * default interval (1/tick)
1164 interval = pmu->hrtimer_interval_ms;
1166 interval = pmu->hrtimer_interval_ms = PERF_CPU_HRTIMER;
1168 cpuctx->hrtimer_interval = ns_to_ktime(NSEC_PER_MSEC * interval);
1170 raw_spin_lock_init(&cpuctx->hrtimer_lock);
1171 hrtimer_init(timer, CLOCK_MONOTONIC, HRTIMER_MODE_ABS_PINNED_HARD);
1172 timer->function = perf_mux_hrtimer_handler;
1175 static int perf_mux_hrtimer_restart(struct perf_cpu_context *cpuctx)
1177 struct hrtimer *timer = &cpuctx->hrtimer;
1178 struct pmu *pmu = cpuctx->ctx.pmu;
1179 unsigned long flags;
1181 /* not for SW PMU */
1182 if (pmu->task_ctx_nr == perf_sw_context)
1185 raw_spin_lock_irqsave(&cpuctx->hrtimer_lock, flags);
1186 if (!cpuctx->hrtimer_active) {
1187 cpuctx->hrtimer_active = 1;
1188 hrtimer_forward_now(timer, cpuctx->hrtimer_interval);
1189 hrtimer_start_expires(timer, HRTIMER_MODE_ABS_PINNED_HARD);
1191 raw_spin_unlock_irqrestore(&cpuctx->hrtimer_lock, flags);
1196 void perf_pmu_disable(struct pmu *pmu)
1198 int *count = this_cpu_ptr(pmu->pmu_disable_count);
1200 pmu->pmu_disable(pmu);
1203 void perf_pmu_enable(struct pmu *pmu)
1205 int *count = this_cpu_ptr(pmu->pmu_disable_count);
1207 pmu->pmu_enable(pmu);
1210 static DEFINE_PER_CPU(struct list_head, active_ctx_list);
1213 * perf_event_ctx_activate(), perf_event_ctx_deactivate(), and
1214 * perf_event_task_tick() are fully serialized because they're strictly cpu
1215 * affine and perf_event_ctx{activate,deactivate} are called with IRQs
1216 * disabled, while perf_event_task_tick is called from IRQ context.
1218 static void perf_event_ctx_activate(struct perf_event_context *ctx)
1220 struct list_head *head = this_cpu_ptr(&active_ctx_list);
1222 lockdep_assert_irqs_disabled();
1224 WARN_ON(!list_empty(&ctx->active_ctx_list));
1226 list_add(&ctx->active_ctx_list, head);
1229 static void perf_event_ctx_deactivate(struct perf_event_context *ctx)
1231 lockdep_assert_irqs_disabled();
1233 WARN_ON(list_empty(&ctx->active_ctx_list));
1235 list_del_init(&ctx->active_ctx_list);
1238 static void get_ctx(struct perf_event_context *ctx)
1240 refcount_inc(&ctx->refcount);
1243 static void *alloc_task_ctx_data(struct pmu *pmu)
1245 if (pmu->task_ctx_cache)
1246 return kmem_cache_zalloc(pmu->task_ctx_cache, GFP_KERNEL);
1251 static void free_task_ctx_data(struct pmu *pmu, void *task_ctx_data)
1253 if (pmu->task_ctx_cache && task_ctx_data)
1254 kmem_cache_free(pmu->task_ctx_cache, task_ctx_data);
1257 static void free_ctx(struct rcu_head *head)
1259 struct perf_event_context *ctx;
1261 ctx = container_of(head, struct perf_event_context, rcu_head);
1262 free_task_ctx_data(ctx->pmu, ctx->task_ctx_data);
1266 static void put_ctx(struct perf_event_context *ctx)
1268 if (refcount_dec_and_test(&ctx->refcount)) {
1269 if (ctx->parent_ctx)
1270 put_ctx(ctx->parent_ctx);
1271 if (ctx->task && ctx->task != TASK_TOMBSTONE)
1272 put_task_struct(ctx->task);
1273 call_rcu(&ctx->rcu_head, free_ctx);
1278 * Because of perf_event::ctx migration in sys_perf_event_open::move_group and
1279 * perf_pmu_migrate_context() we need some magic.
1281 * Those places that change perf_event::ctx will hold both
1282 * perf_event_ctx::mutex of the 'old' and 'new' ctx value.
1284 * Lock ordering is by mutex address. There are two other sites where
1285 * perf_event_context::mutex nests and those are:
1287 * - perf_event_exit_task_context() [ child , 0 ]
1288 * perf_event_exit_event()
1289 * put_event() [ parent, 1 ]
1291 * - perf_event_init_context() [ parent, 0 ]
1292 * inherit_task_group()
1295 * perf_event_alloc()
1297 * perf_try_init_event() [ child , 1 ]
1299 * While it appears there is an obvious deadlock here -- the parent and child
1300 * nesting levels are inverted between the two. This is in fact safe because
1301 * life-time rules separate them. That is an exiting task cannot fork, and a
1302 * spawning task cannot (yet) exit.
1304 * But remember that these are parent<->child context relations, and
1305 * migration does not affect children, therefore these two orderings should not
1308 * The change in perf_event::ctx does not affect children (as claimed above)
1309 * because the sys_perf_event_open() case will install a new event and break
1310 * the ctx parent<->child relation, and perf_pmu_migrate_context() is only
1311 * concerned with cpuctx and that doesn't have children.
1313 * The places that change perf_event::ctx will issue:
1315 * perf_remove_from_context();
1316 * synchronize_rcu();
1317 * perf_install_in_context();
1319 * to affect the change. The remove_from_context() + synchronize_rcu() should
1320 * quiesce the event, after which we can install it in the new location. This
1321 * means that only external vectors (perf_fops, prctl) can perturb the event
1322 * while in transit. Therefore all such accessors should also acquire
1323 * perf_event_context::mutex to serialize against this.
1325 * However; because event->ctx can change while we're waiting to acquire
1326 * ctx->mutex we must be careful and use the below perf_event_ctx_lock()
1331 * task_struct::perf_event_mutex
1332 * perf_event_context::mutex
1333 * perf_event::child_mutex;
1334 * perf_event_context::lock
1335 * perf_event::mmap_mutex
1337 * perf_addr_filters_head::lock
1341 * cpuctx->mutex / perf_event_context::mutex
1343 static struct perf_event_context *
1344 perf_event_ctx_lock_nested(struct perf_event *event, int nesting)
1346 struct perf_event_context *ctx;
1350 ctx = READ_ONCE(event->ctx);
1351 if (!refcount_inc_not_zero(&ctx->refcount)) {
1357 mutex_lock_nested(&ctx->mutex, nesting);
1358 if (event->ctx != ctx) {
1359 mutex_unlock(&ctx->mutex);
1367 static inline struct perf_event_context *
1368 perf_event_ctx_lock(struct perf_event *event)
1370 return perf_event_ctx_lock_nested(event, 0);
1373 static void perf_event_ctx_unlock(struct perf_event *event,
1374 struct perf_event_context *ctx)
1376 mutex_unlock(&ctx->mutex);
1381 * This must be done under the ctx->lock, such as to serialize against
1382 * context_equiv(), therefore we cannot call put_ctx() since that might end up
1383 * calling scheduler related locks and ctx->lock nests inside those.
1385 static __must_check struct perf_event_context *
1386 unclone_ctx(struct perf_event_context *ctx)
1388 struct perf_event_context *parent_ctx = ctx->parent_ctx;
1390 lockdep_assert_held(&ctx->lock);
1393 ctx->parent_ctx = NULL;
1399 static u32 perf_event_pid_type(struct perf_event *event, struct task_struct *p,
1404 * only top level events have the pid namespace they were created in
1407 event = event->parent;
1409 nr = __task_pid_nr_ns(p, type, event->ns);
1410 /* avoid -1 if it is idle thread or runs in another ns */
1411 if (!nr && !pid_alive(p))
1416 static u32 perf_event_pid(struct perf_event *event, struct task_struct *p)
1418 return perf_event_pid_type(event, p, PIDTYPE_TGID);
1421 static u32 perf_event_tid(struct perf_event *event, struct task_struct *p)
1423 return perf_event_pid_type(event, p, PIDTYPE_PID);
1427 * If we inherit events we want to return the parent event id
1430 static u64 primary_event_id(struct perf_event *event)
1435 id = event->parent->id;
1441 * Get the perf_event_context for a task and lock it.
1443 * This has to cope with the fact that until it is locked,
1444 * the context could get moved to another task.
1446 static struct perf_event_context *
1447 perf_lock_task_context(struct task_struct *task, int ctxn, unsigned long *flags)
1449 struct perf_event_context *ctx;
1453 * One of the few rules of preemptible RCU is that one cannot do
1454 * rcu_read_unlock() while holding a scheduler (or nested) lock when
1455 * part of the read side critical section was irqs-enabled -- see
1456 * rcu_read_unlock_special().
1458 * Since ctx->lock nests under rq->lock we must ensure the entire read
1459 * side critical section has interrupts disabled.
1461 local_irq_save(*flags);
1463 ctx = rcu_dereference(task->perf_event_ctxp[ctxn]);
1466 * If this context is a clone of another, it might
1467 * get swapped for another underneath us by
1468 * perf_event_task_sched_out, though the
1469 * rcu_read_lock() protects us from any context
1470 * getting freed. Lock the context and check if it
1471 * got swapped before we could get the lock, and retry
1472 * if so. If we locked the right context, then it
1473 * can't get swapped on us any more.
1475 raw_spin_lock(&ctx->lock);
1476 if (ctx != rcu_dereference(task->perf_event_ctxp[ctxn])) {
1477 raw_spin_unlock(&ctx->lock);
1479 local_irq_restore(*flags);
1483 if (ctx->task == TASK_TOMBSTONE ||
1484 !refcount_inc_not_zero(&ctx->refcount)) {
1485 raw_spin_unlock(&ctx->lock);
1488 WARN_ON_ONCE(ctx->task != task);
1493 local_irq_restore(*flags);
1498 * Get the context for a task and increment its pin_count so it
1499 * can't get swapped to another task. This also increments its
1500 * reference count so that the context can't get freed.
1502 static struct perf_event_context *
1503 perf_pin_task_context(struct task_struct *task, int ctxn)
1505 struct perf_event_context *ctx;
1506 unsigned long flags;
1508 ctx = perf_lock_task_context(task, ctxn, &flags);
1511 raw_spin_unlock_irqrestore(&ctx->lock, flags);
1516 static void perf_unpin_context(struct perf_event_context *ctx)
1518 unsigned long flags;
1520 raw_spin_lock_irqsave(&ctx->lock, flags);
1522 raw_spin_unlock_irqrestore(&ctx->lock, flags);
1526 * Update the record of the current time in a context.
1528 static void update_context_time(struct perf_event_context *ctx)
1530 u64 now = perf_clock();
1532 ctx->time += now - ctx->timestamp;
1533 ctx->timestamp = now;
1536 static u64 perf_event_time(struct perf_event *event)
1538 struct perf_event_context *ctx = event->ctx;
1540 if (is_cgroup_event(event))
1541 return perf_cgroup_event_time(event);
1543 return ctx ? ctx->time : 0;
1546 static enum event_type_t get_event_type(struct perf_event *event)
1548 struct perf_event_context *ctx = event->ctx;
1549 enum event_type_t event_type;
1551 lockdep_assert_held(&ctx->lock);
1554 * It's 'group type', really, because if our group leader is
1555 * pinned, so are we.
1557 if (event->group_leader != event)
1558 event = event->group_leader;
1560 event_type = event->attr.pinned ? EVENT_PINNED : EVENT_FLEXIBLE;
1562 event_type |= EVENT_CPU;
1568 * Helper function to initialize event group nodes.
1570 static void init_event_group(struct perf_event *event)
1572 RB_CLEAR_NODE(&event->group_node);
1573 event->group_index = 0;
1577 * Extract pinned or flexible groups from the context
1578 * based on event attrs bits.
1580 static struct perf_event_groups *
1581 get_event_groups(struct perf_event *event, struct perf_event_context *ctx)
1583 if (event->attr.pinned)
1584 return &ctx->pinned_groups;
1586 return &ctx->flexible_groups;
1590 * Helper function to initializes perf_event_group trees.
1592 static void perf_event_groups_init(struct perf_event_groups *groups)
1594 groups->tree = RB_ROOT;
1598 static inline struct cgroup *event_cgroup(const struct perf_event *event)
1600 struct cgroup *cgroup = NULL;
1602 #ifdef CONFIG_CGROUP_PERF
1604 cgroup = event->cgrp->css.cgroup;
1611 * Compare function for event groups;
1613 * Implements complex key that first sorts by CPU and then by virtual index
1614 * which provides ordering when rotating groups for the same CPU.
1616 static __always_inline int
1617 perf_event_groups_cmp(const int left_cpu, const struct cgroup *left_cgroup,
1618 const u64 left_group_index, const struct perf_event *right)
1620 if (left_cpu < right->cpu)
1622 if (left_cpu > right->cpu)
1625 #ifdef CONFIG_CGROUP_PERF
1627 const struct cgroup *right_cgroup = event_cgroup(right);
1629 if (left_cgroup != right_cgroup) {
1632 * Left has no cgroup but right does, no
1633 * cgroups come first.
1637 if (!right_cgroup) {
1639 * Right has no cgroup but left does, no
1640 * cgroups come first.
1644 /* Two dissimilar cgroups, order by id. */
1645 if (cgroup_id(left_cgroup) < cgroup_id(right_cgroup))
1653 if (left_group_index < right->group_index)
1655 if (left_group_index > right->group_index)
1661 #define __node_2_pe(node) \
1662 rb_entry((node), struct perf_event, group_node)
1664 static inline bool __group_less(struct rb_node *a, const struct rb_node *b)
1666 struct perf_event *e = __node_2_pe(a);
1667 return perf_event_groups_cmp(e->cpu, event_cgroup(e), e->group_index,
1668 __node_2_pe(b)) < 0;
1671 struct __group_key {
1673 struct cgroup *cgroup;
1676 static inline int __group_cmp(const void *key, const struct rb_node *node)
1678 const struct __group_key *a = key;
1679 const struct perf_event *b = __node_2_pe(node);
1681 /* partial/subtree match: @cpu, @cgroup; ignore: @group_index */
1682 return perf_event_groups_cmp(a->cpu, a->cgroup, b->group_index, b);
1686 * Insert @event into @groups' tree; using {@event->cpu, ++@groups->index} for
1687 * key (see perf_event_groups_less). This places it last inside the CPU
1691 perf_event_groups_insert(struct perf_event_groups *groups,
1692 struct perf_event *event)
1694 event->group_index = ++groups->index;
1696 rb_add(&event->group_node, &groups->tree, __group_less);
1700 * Helper function to insert event into the pinned or flexible groups.
1703 add_event_to_groups(struct perf_event *event, struct perf_event_context *ctx)
1705 struct perf_event_groups *groups;
1707 groups = get_event_groups(event, ctx);
1708 perf_event_groups_insert(groups, event);
1712 * Delete a group from a tree.
1715 perf_event_groups_delete(struct perf_event_groups *groups,
1716 struct perf_event *event)
1718 WARN_ON_ONCE(RB_EMPTY_NODE(&event->group_node) ||
1719 RB_EMPTY_ROOT(&groups->tree));
1721 rb_erase(&event->group_node, &groups->tree);
1722 init_event_group(event);
1726 * Helper function to delete event from its groups.
1729 del_event_from_groups(struct perf_event *event, struct perf_event_context *ctx)
1731 struct perf_event_groups *groups;
1733 groups = get_event_groups(event, ctx);
1734 perf_event_groups_delete(groups, event);
1738 * Get the leftmost event in the cpu/cgroup subtree.
1740 static struct perf_event *
1741 perf_event_groups_first(struct perf_event_groups *groups, int cpu,
1742 struct cgroup *cgrp)
1744 struct __group_key key = {
1748 struct rb_node *node;
1750 node = rb_find_first(&key, &groups->tree, __group_cmp);
1752 return __node_2_pe(node);
1758 * Like rb_entry_next_safe() for the @cpu subtree.
1760 static struct perf_event *
1761 perf_event_groups_next(struct perf_event *event)
1763 struct __group_key key = {
1765 .cgroup = event_cgroup(event),
1767 struct rb_node *next;
1769 next = rb_next_match(&key, &event->group_node, __group_cmp);
1771 return __node_2_pe(next);
1777 * Iterate through the whole groups tree.
1779 #define perf_event_groups_for_each(event, groups) \
1780 for (event = rb_entry_safe(rb_first(&((groups)->tree)), \
1781 typeof(*event), group_node); event; \
1782 event = rb_entry_safe(rb_next(&event->group_node), \
1783 typeof(*event), group_node))
1786 * Add an event from the lists for its context.
1787 * Must be called with ctx->mutex and ctx->lock held.
1790 list_add_event(struct perf_event *event, struct perf_event_context *ctx)
1792 lockdep_assert_held(&ctx->lock);
1794 WARN_ON_ONCE(event->attach_state & PERF_ATTACH_CONTEXT);
1795 event->attach_state |= PERF_ATTACH_CONTEXT;
1797 event->tstamp = perf_event_time(event);
1800 * If we're a stand alone event or group leader, we go to the context
1801 * list, group events are kept attached to the group so that
1802 * perf_group_detach can, at all times, locate all siblings.
1804 if (event->group_leader == event) {
1805 event->group_caps = event->event_caps;
1806 add_event_to_groups(event, ctx);
1809 list_add_rcu(&event->event_entry, &ctx->event_list);
1811 if (event->attr.inherit_stat)
1814 if (event->state > PERF_EVENT_STATE_OFF)
1815 perf_cgroup_event_enable(event, ctx);
1821 * Initialize event state based on the perf_event_attr::disabled.
1823 static inline void perf_event__state_init(struct perf_event *event)
1825 event->state = event->attr.disabled ? PERF_EVENT_STATE_OFF :
1826 PERF_EVENT_STATE_INACTIVE;
1829 static void __perf_event_read_size(struct perf_event *event, int nr_siblings)
1831 int entry = sizeof(u64); /* value */
1835 if (event->attr.read_format & PERF_FORMAT_TOTAL_TIME_ENABLED)
1836 size += sizeof(u64);
1838 if (event->attr.read_format & PERF_FORMAT_TOTAL_TIME_RUNNING)
1839 size += sizeof(u64);
1841 if (event->attr.read_format & PERF_FORMAT_ID)
1842 entry += sizeof(u64);
1844 if (event->attr.read_format & PERF_FORMAT_GROUP) {
1846 size += sizeof(u64);
1850 event->read_size = size;
1853 static void __perf_event_header_size(struct perf_event *event, u64 sample_type)
1855 struct perf_sample_data *data;
1858 if (sample_type & PERF_SAMPLE_IP)
1859 size += sizeof(data->ip);
1861 if (sample_type & PERF_SAMPLE_ADDR)
1862 size += sizeof(data->addr);
1864 if (sample_type & PERF_SAMPLE_PERIOD)
1865 size += sizeof(data->period);
1867 if (sample_type & PERF_SAMPLE_WEIGHT_TYPE)
1868 size += sizeof(data->weight.full);
1870 if (sample_type & PERF_SAMPLE_READ)
1871 size += event->read_size;
1873 if (sample_type & PERF_SAMPLE_DATA_SRC)
1874 size += sizeof(data->data_src.val);
1876 if (sample_type & PERF_SAMPLE_TRANSACTION)
1877 size += sizeof(data->txn);
1879 if (sample_type & PERF_SAMPLE_PHYS_ADDR)
1880 size += sizeof(data->phys_addr);
1882 if (sample_type & PERF_SAMPLE_CGROUP)
1883 size += sizeof(data->cgroup);
1885 if (sample_type & PERF_SAMPLE_DATA_PAGE_SIZE)
1886 size += sizeof(data->data_page_size);
1888 if (sample_type & PERF_SAMPLE_CODE_PAGE_SIZE)
1889 size += sizeof(data->code_page_size);
1891 event->header_size = size;
1895 * Called at perf_event creation and when events are attached/detached from a
1898 static void perf_event__header_size(struct perf_event *event)
1900 __perf_event_read_size(event,
1901 event->group_leader->nr_siblings);
1902 __perf_event_header_size(event, event->attr.sample_type);
1905 static void perf_event__id_header_size(struct perf_event *event)
1907 struct perf_sample_data *data;
1908 u64 sample_type = event->attr.sample_type;
1911 if (sample_type & PERF_SAMPLE_TID)
1912 size += sizeof(data->tid_entry);
1914 if (sample_type & PERF_SAMPLE_TIME)
1915 size += sizeof(data->time);
1917 if (sample_type & PERF_SAMPLE_IDENTIFIER)
1918 size += sizeof(data->id);
1920 if (sample_type & PERF_SAMPLE_ID)
1921 size += sizeof(data->id);
1923 if (sample_type & PERF_SAMPLE_STREAM_ID)
1924 size += sizeof(data->stream_id);
1926 if (sample_type & PERF_SAMPLE_CPU)
1927 size += sizeof(data->cpu_entry);
1929 event->id_header_size = size;
1932 static bool perf_event_validate_size(struct perf_event *event)
1935 * The values computed here will be over-written when we actually
1938 __perf_event_read_size(event, event->group_leader->nr_siblings + 1);
1939 __perf_event_header_size(event, event->attr.sample_type & ~PERF_SAMPLE_READ);
1940 perf_event__id_header_size(event);
1943 * Sum the lot; should not exceed the 64k limit we have on records.
1944 * Conservative limit to allow for callchains and other variable fields.
1946 if (event->read_size + event->header_size +
1947 event->id_header_size + sizeof(struct perf_event_header) >= 16*1024)
1953 static void perf_group_attach(struct perf_event *event)
1955 struct perf_event *group_leader = event->group_leader, *pos;
1957 lockdep_assert_held(&event->ctx->lock);
1960 * We can have double attach due to group movement in perf_event_open.
1962 if (event->attach_state & PERF_ATTACH_GROUP)
1965 event->attach_state |= PERF_ATTACH_GROUP;
1967 if (group_leader == event)
1970 WARN_ON_ONCE(group_leader->ctx != event->ctx);
1972 group_leader->group_caps &= event->event_caps;
1974 list_add_tail(&event->sibling_list, &group_leader->sibling_list);
1975 group_leader->nr_siblings++;
1977 perf_event__header_size(group_leader);
1979 for_each_sibling_event(pos, group_leader)
1980 perf_event__header_size(pos);
1984 * Remove an event from the lists for its context.
1985 * Must be called with ctx->mutex and ctx->lock held.
1988 list_del_event(struct perf_event *event, struct perf_event_context *ctx)
1990 WARN_ON_ONCE(event->ctx != ctx);
1991 lockdep_assert_held(&ctx->lock);
1994 * We can have double detach due to exit/hot-unplug + close.
1996 if (!(event->attach_state & PERF_ATTACH_CONTEXT))
1999 event->attach_state &= ~PERF_ATTACH_CONTEXT;
2002 if (event->attr.inherit_stat)
2005 list_del_rcu(&event->event_entry);
2007 if (event->group_leader == event)
2008 del_event_from_groups(event, ctx);
2011 * If event was in error state, then keep it
2012 * that way, otherwise bogus counts will be
2013 * returned on read(). The only way to get out
2014 * of error state is by explicit re-enabling
2017 if (event->state > PERF_EVENT_STATE_OFF) {
2018 perf_cgroup_event_disable(event, ctx);
2019 perf_event_set_state(event, PERF_EVENT_STATE_OFF);
2026 perf_aux_output_match(struct perf_event *event, struct perf_event *aux_event)
2028 if (!has_aux(aux_event))
2031 if (!event->pmu->aux_output_match)
2034 return event->pmu->aux_output_match(aux_event);
2037 static void put_event(struct perf_event *event);
2038 static void event_sched_out(struct perf_event *event,
2039 struct perf_cpu_context *cpuctx,
2040 struct perf_event_context *ctx);
2042 static void perf_put_aux_event(struct perf_event *event)
2044 struct perf_event_context *ctx = event->ctx;
2045 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
2046 struct perf_event *iter;
2049 * If event uses aux_event tear down the link
2051 if (event->aux_event) {
2052 iter = event->aux_event;
2053 event->aux_event = NULL;
2059 * If the event is an aux_event, tear down all links to
2060 * it from other events.
2062 for_each_sibling_event(iter, event->group_leader) {
2063 if (iter->aux_event != event)
2066 iter->aux_event = NULL;
2070 * If it's ACTIVE, schedule it out and put it into ERROR
2071 * state so that we don't try to schedule it again. Note
2072 * that perf_event_enable() will clear the ERROR status.
2074 event_sched_out(iter, cpuctx, ctx);
2075 perf_event_set_state(event, PERF_EVENT_STATE_ERROR);
2079 static bool perf_need_aux_event(struct perf_event *event)
2081 return !!event->attr.aux_output || !!event->attr.aux_sample_size;
2084 static int perf_get_aux_event(struct perf_event *event,
2085 struct perf_event *group_leader)
2088 * Our group leader must be an aux event if we want to be
2089 * an aux_output. This way, the aux event will precede its
2090 * aux_output events in the group, and therefore will always
2097 * aux_output and aux_sample_size are mutually exclusive.
2099 if (event->attr.aux_output && event->attr.aux_sample_size)
2102 if (event->attr.aux_output &&
2103 !perf_aux_output_match(event, group_leader))
2106 if (event->attr.aux_sample_size && !group_leader->pmu->snapshot_aux)
2109 if (!atomic_long_inc_not_zero(&group_leader->refcount))
2113 * Link aux_outputs to their aux event; this is undone in
2114 * perf_group_detach() by perf_put_aux_event(). When the
2115 * group in torn down, the aux_output events loose their
2116 * link to the aux_event and can't schedule any more.
2118 event->aux_event = group_leader;
2123 static inline struct list_head *get_event_list(struct perf_event *event)
2125 struct perf_event_context *ctx = event->ctx;
2126 return event->attr.pinned ? &ctx->pinned_active : &ctx->flexible_active;
2130 * Events that have PERF_EV_CAP_SIBLING require being part of a group and
2131 * cannot exist on their own, schedule them out and move them into the ERROR
2132 * state. Also see _perf_event_enable(), it will not be able to recover
2135 static inline void perf_remove_sibling_event(struct perf_event *event)
2137 struct perf_event_context *ctx = event->ctx;
2138 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
2140 event_sched_out(event, cpuctx, ctx);
2141 perf_event_set_state(event, PERF_EVENT_STATE_ERROR);
2144 static void perf_group_detach(struct perf_event *event)
2146 struct perf_event *leader = event->group_leader;
2147 struct perf_event *sibling, *tmp;
2148 struct perf_event_context *ctx = event->ctx;
2150 lockdep_assert_held(&ctx->lock);
2153 * We can have double detach due to exit/hot-unplug + close.
2155 if (!(event->attach_state & PERF_ATTACH_GROUP))
2158 event->attach_state &= ~PERF_ATTACH_GROUP;
2160 perf_put_aux_event(event);
2163 * If this is a sibling, remove it from its group.
2165 if (leader != event) {
2166 list_del_init(&event->sibling_list);
2167 event->group_leader->nr_siblings--;
2172 * If this was a group event with sibling events then
2173 * upgrade the siblings to singleton events by adding them
2174 * to whatever list we are on.
2176 list_for_each_entry_safe(sibling, tmp, &event->sibling_list, sibling_list) {
2178 if (sibling->event_caps & PERF_EV_CAP_SIBLING)
2179 perf_remove_sibling_event(sibling);
2181 sibling->group_leader = sibling;
2182 list_del_init(&sibling->sibling_list);
2184 /* Inherit group flags from the previous leader */
2185 sibling->group_caps = event->group_caps;
2187 if (!RB_EMPTY_NODE(&event->group_node)) {
2188 add_event_to_groups(sibling, event->ctx);
2190 if (sibling->state == PERF_EVENT_STATE_ACTIVE)
2191 list_add_tail(&sibling->active_list, get_event_list(sibling));
2194 WARN_ON_ONCE(sibling->ctx != event->ctx);
2198 for_each_sibling_event(tmp, leader)
2199 perf_event__header_size(tmp);
2201 perf_event__header_size(leader);
2204 static void sync_child_event(struct perf_event *child_event);
2206 static void perf_child_detach(struct perf_event *event)
2208 struct perf_event *parent_event = event->parent;
2210 if (!(event->attach_state & PERF_ATTACH_CHILD))
2213 event->attach_state &= ~PERF_ATTACH_CHILD;
2215 if (WARN_ON_ONCE(!parent_event))
2218 lockdep_assert_held(&parent_event->child_mutex);
2220 sync_child_event(event);
2221 list_del_init(&event->child_list);
2224 static bool is_orphaned_event(struct perf_event *event)
2226 return event->state == PERF_EVENT_STATE_DEAD;
2229 static inline int __pmu_filter_match(struct perf_event *event)
2231 struct pmu *pmu = event->pmu;
2232 return pmu->filter_match ? pmu->filter_match(event) : 1;
2236 * Check whether we should attempt to schedule an event group based on
2237 * PMU-specific filtering. An event group can consist of HW and SW events,
2238 * potentially with a SW leader, so we must check all the filters, to
2239 * determine whether a group is schedulable:
2241 static inline int pmu_filter_match(struct perf_event *event)
2243 struct perf_event *sibling;
2245 if (!__pmu_filter_match(event))
2248 for_each_sibling_event(sibling, event) {
2249 if (!__pmu_filter_match(sibling))
2257 event_filter_match(struct perf_event *event)
2259 return (event->cpu == -1 || event->cpu == smp_processor_id()) &&
2260 perf_cgroup_match(event) && pmu_filter_match(event);
2264 event_sched_out(struct perf_event *event,
2265 struct perf_cpu_context *cpuctx,
2266 struct perf_event_context *ctx)
2268 enum perf_event_state state = PERF_EVENT_STATE_INACTIVE;
2270 WARN_ON_ONCE(event->ctx != ctx);
2271 lockdep_assert_held(&ctx->lock);
2273 if (event->state != PERF_EVENT_STATE_ACTIVE)
2277 * Asymmetry; we only schedule events _IN_ through ctx_sched_in(), but
2278 * we can schedule events _OUT_ individually through things like
2279 * __perf_remove_from_context().
2281 list_del_init(&event->active_list);
2283 perf_pmu_disable(event->pmu);
2285 event->pmu->del(event, 0);
2288 if (READ_ONCE(event->pending_disable) >= 0) {
2289 WRITE_ONCE(event->pending_disable, -1);
2290 perf_cgroup_event_disable(event, ctx);
2291 state = PERF_EVENT_STATE_OFF;
2293 perf_event_set_state(event, state);
2295 if (!is_software_event(event))
2296 cpuctx->active_oncpu--;
2297 if (!--ctx->nr_active)
2298 perf_event_ctx_deactivate(ctx);
2299 if (event->attr.freq && event->attr.sample_freq)
2301 if (event->attr.exclusive || !cpuctx->active_oncpu)
2302 cpuctx->exclusive = 0;
2304 perf_pmu_enable(event->pmu);
2308 group_sched_out(struct perf_event *group_event,
2309 struct perf_cpu_context *cpuctx,
2310 struct perf_event_context *ctx)
2312 struct perf_event *event;
2314 if (group_event->state != PERF_EVENT_STATE_ACTIVE)
2317 perf_pmu_disable(ctx->pmu);
2319 event_sched_out(group_event, cpuctx, ctx);
2322 * Schedule out siblings (if any):
2324 for_each_sibling_event(event, group_event)
2325 event_sched_out(event, cpuctx, ctx);
2327 perf_pmu_enable(ctx->pmu);
2330 #define DETACH_GROUP 0x01UL
2331 #define DETACH_CHILD 0x02UL
2334 * Cross CPU call to remove a performance event
2336 * We disable the event on the hardware level first. After that we
2337 * remove it from the context list.
2340 __perf_remove_from_context(struct perf_event *event,
2341 struct perf_cpu_context *cpuctx,
2342 struct perf_event_context *ctx,
2345 unsigned long flags = (unsigned long)info;
2347 if (ctx->is_active & EVENT_TIME) {
2348 update_context_time(ctx);
2349 update_cgrp_time_from_cpuctx(cpuctx);
2352 event_sched_out(event, cpuctx, ctx);
2353 if (flags & DETACH_GROUP)
2354 perf_group_detach(event);
2355 if (flags & DETACH_CHILD)
2356 perf_child_detach(event);
2357 list_del_event(event, ctx);
2359 if (!ctx->nr_events && ctx->is_active) {
2361 ctx->rotate_necessary = 0;
2363 WARN_ON_ONCE(cpuctx->task_ctx != ctx);
2364 cpuctx->task_ctx = NULL;
2370 * Remove the event from a task's (or a CPU's) list of events.
2372 * If event->ctx is a cloned context, callers must make sure that
2373 * every task struct that event->ctx->task could possibly point to
2374 * remains valid. This is OK when called from perf_release since
2375 * that only calls us on the top-level context, which can't be a clone.
2376 * When called from perf_event_exit_task, it's OK because the
2377 * context has been detached from its task.
2379 static void perf_remove_from_context(struct perf_event *event, unsigned long flags)
2381 struct perf_event_context *ctx = event->ctx;
2383 lockdep_assert_held(&ctx->mutex);
2386 * Because of perf_event_exit_task(), perf_remove_from_context() ought
2387 * to work in the face of TASK_TOMBSTONE, unlike every other
2388 * event_function_call() user.
2390 raw_spin_lock_irq(&ctx->lock);
2391 if (!ctx->is_active) {
2392 __perf_remove_from_context(event, __get_cpu_context(ctx),
2393 ctx, (void *)flags);
2394 raw_spin_unlock_irq(&ctx->lock);
2397 raw_spin_unlock_irq(&ctx->lock);
2399 event_function_call(event, __perf_remove_from_context, (void *)flags);
2403 * Cross CPU call to disable a performance event
2405 static void __perf_event_disable(struct perf_event *event,
2406 struct perf_cpu_context *cpuctx,
2407 struct perf_event_context *ctx,
2410 if (event->state < PERF_EVENT_STATE_INACTIVE)
2413 if (ctx->is_active & EVENT_TIME) {
2414 update_context_time(ctx);
2415 update_cgrp_time_from_event(event);
2418 if (event == event->group_leader)
2419 group_sched_out(event, cpuctx, ctx);
2421 event_sched_out(event, cpuctx, ctx);
2423 perf_event_set_state(event, PERF_EVENT_STATE_OFF);
2424 perf_cgroup_event_disable(event, ctx);
2430 * If event->ctx is a cloned context, callers must make sure that
2431 * every task struct that event->ctx->task could possibly point to
2432 * remains valid. This condition is satisfied when called through
2433 * perf_event_for_each_child or perf_event_for_each because they
2434 * hold the top-level event's child_mutex, so any descendant that
2435 * goes to exit will block in perf_event_exit_event().
2437 * When called from perf_pending_event it's OK because event->ctx
2438 * is the current context on this CPU and preemption is disabled,
2439 * hence we can't get into perf_event_task_sched_out for this context.
2441 static void _perf_event_disable(struct perf_event *event)
2443 struct perf_event_context *ctx = event->ctx;
2445 raw_spin_lock_irq(&ctx->lock);
2446 if (event->state <= PERF_EVENT_STATE_OFF) {
2447 raw_spin_unlock_irq(&ctx->lock);
2450 raw_spin_unlock_irq(&ctx->lock);
2452 event_function_call(event, __perf_event_disable, NULL);
2455 void perf_event_disable_local(struct perf_event *event)
2457 event_function_local(event, __perf_event_disable, NULL);
2461 * Strictly speaking kernel users cannot create groups and therefore this
2462 * interface does not need the perf_event_ctx_lock() magic.
2464 void perf_event_disable(struct perf_event *event)
2466 struct perf_event_context *ctx;
2468 ctx = perf_event_ctx_lock(event);
2469 _perf_event_disable(event);
2470 perf_event_ctx_unlock(event, ctx);
2472 EXPORT_SYMBOL_GPL(perf_event_disable);
2474 void perf_event_disable_inatomic(struct perf_event *event)
2476 WRITE_ONCE(event->pending_disable, smp_processor_id());
2477 /* can fail, see perf_pending_event_disable() */
2478 irq_work_queue(&event->pending);
2481 static void perf_set_shadow_time(struct perf_event *event,
2482 struct perf_event_context *ctx)
2485 * use the correct time source for the time snapshot
2487 * We could get by without this by leveraging the
2488 * fact that to get to this function, the caller
2489 * has most likely already called update_context_time()
2490 * and update_cgrp_time_xx() and thus both timestamp
2491 * are identical (or very close). Given that tstamp is,
2492 * already adjusted for cgroup, we could say that:
2493 * tstamp - ctx->timestamp
2495 * tstamp - cgrp->timestamp.
2497 * Then, in perf_output_read(), the calculation would
2498 * work with no changes because:
2499 * - event is guaranteed scheduled in
2500 * - no scheduled out in between
2501 * - thus the timestamp would be the same
2503 * But this is a bit hairy.
2505 * So instead, we have an explicit cgroup call to remain
2506 * within the time source all along. We believe it
2507 * is cleaner and simpler to understand.
2509 if (is_cgroup_event(event))
2510 perf_cgroup_set_shadow_time(event, event->tstamp);
2512 event->shadow_ctx_time = event->tstamp - ctx->timestamp;
2515 #define MAX_INTERRUPTS (~0ULL)
2517 static void perf_log_throttle(struct perf_event *event, int enable);
2518 static void perf_log_itrace_start(struct perf_event *event);
2521 event_sched_in(struct perf_event *event,
2522 struct perf_cpu_context *cpuctx,
2523 struct perf_event_context *ctx)
2527 WARN_ON_ONCE(event->ctx != ctx);
2529 lockdep_assert_held(&ctx->lock);
2531 if (event->state <= PERF_EVENT_STATE_OFF)
2534 WRITE_ONCE(event->oncpu, smp_processor_id());
2536 * Order event::oncpu write to happen before the ACTIVE state is
2537 * visible. This allows perf_event_{stop,read}() to observe the correct
2538 * ->oncpu if it sees ACTIVE.
2541 perf_event_set_state(event, PERF_EVENT_STATE_ACTIVE);
2544 * Unthrottle events, since we scheduled we might have missed several
2545 * ticks already, also for a heavily scheduling task there is little
2546 * guarantee it'll get a tick in a timely manner.
2548 if (unlikely(event->hw.interrupts == MAX_INTERRUPTS)) {
2549 perf_log_throttle(event, 1);
2550 event->hw.interrupts = 0;
2553 perf_pmu_disable(event->pmu);
2555 perf_set_shadow_time(event, ctx);
2557 perf_log_itrace_start(event);
2559 if (event->pmu->add(event, PERF_EF_START)) {
2560 perf_event_set_state(event, PERF_EVENT_STATE_INACTIVE);
2566 if (!is_software_event(event))
2567 cpuctx->active_oncpu++;
2568 if (!ctx->nr_active++)
2569 perf_event_ctx_activate(ctx);
2570 if (event->attr.freq && event->attr.sample_freq)
2573 if (event->attr.exclusive)
2574 cpuctx->exclusive = 1;
2577 perf_pmu_enable(event->pmu);
2583 group_sched_in(struct perf_event *group_event,
2584 struct perf_cpu_context *cpuctx,
2585 struct perf_event_context *ctx)
2587 struct perf_event *event, *partial_group = NULL;
2588 struct pmu *pmu = ctx->pmu;
2590 if (group_event->state == PERF_EVENT_STATE_OFF)
2593 pmu->start_txn(pmu, PERF_PMU_TXN_ADD);
2595 if (event_sched_in(group_event, cpuctx, ctx))
2599 * Schedule in siblings as one group (if any):
2601 for_each_sibling_event(event, group_event) {
2602 if (event_sched_in(event, cpuctx, ctx)) {
2603 partial_group = event;
2608 if (!pmu->commit_txn(pmu))
2613 * Groups can be scheduled in as one unit only, so undo any
2614 * partial group before returning:
2615 * The events up to the failed event are scheduled out normally.
2617 for_each_sibling_event(event, group_event) {
2618 if (event == partial_group)
2621 event_sched_out(event, cpuctx, ctx);
2623 event_sched_out(group_event, cpuctx, ctx);
2626 pmu->cancel_txn(pmu);
2631 * Work out whether we can put this event group on the CPU now.
2633 static int group_can_go_on(struct perf_event *event,
2634 struct perf_cpu_context *cpuctx,
2638 * Groups consisting entirely of software events can always go on.
2640 if (event->group_caps & PERF_EV_CAP_SOFTWARE)
2643 * If an exclusive group is already on, no other hardware
2646 if (cpuctx->exclusive)
2649 * If this group is exclusive and there are already
2650 * events on the CPU, it can't go on.
2652 if (event->attr.exclusive && !list_empty(get_event_list(event)))
2655 * Otherwise, try to add it if all previous groups were able
2661 static void add_event_to_ctx(struct perf_event *event,
2662 struct perf_event_context *ctx)
2664 list_add_event(event, ctx);
2665 perf_group_attach(event);
2668 static void ctx_sched_out(struct perf_event_context *ctx,
2669 struct perf_cpu_context *cpuctx,
2670 enum event_type_t event_type);
2672 ctx_sched_in(struct perf_event_context *ctx,
2673 struct perf_cpu_context *cpuctx,
2674 enum event_type_t event_type,
2675 struct task_struct *task);
2677 static void task_ctx_sched_out(struct perf_cpu_context *cpuctx,
2678 struct perf_event_context *ctx,
2679 enum event_type_t event_type)
2681 if (!cpuctx->task_ctx)
2684 if (WARN_ON_ONCE(ctx != cpuctx->task_ctx))
2687 ctx_sched_out(ctx, cpuctx, event_type);
2690 static void perf_event_sched_in(struct perf_cpu_context *cpuctx,
2691 struct perf_event_context *ctx,
2692 struct task_struct *task)
2694 cpu_ctx_sched_in(cpuctx, EVENT_PINNED, task);
2696 ctx_sched_in(ctx, cpuctx, EVENT_PINNED, task);
2697 cpu_ctx_sched_in(cpuctx, EVENT_FLEXIBLE, task);
2699 ctx_sched_in(ctx, cpuctx, EVENT_FLEXIBLE, task);
2703 * We want to maintain the following priority of scheduling:
2704 * - CPU pinned (EVENT_CPU | EVENT_PINNED)
2705 * - task pinned (EVENT_PINNED)
2706 * - CPU flexible (EVENT_CPU | EVENT_FLEXIBLE)
2707 * - task flexible (EVENT_FLEXIBLE).
2709 * In order to avoid unscheduling and scheduling back in everything every
2710 * time an event is added, only do it for the groups of equal priority and
2713 * This can be called after a batch operation on task events, in which case
2714 * event_type is a bit mask of the types of events involved. For CPU events,
2715 * event_type is only either EVENT_PINNED or EVENT_FLEXIBLE.
2717 static void ctx_resched(struct perf_cpu_context *cpuctx,
2718 struct perf_event_context *task_ctx,
2719 enum event_type_t event_type)
2721 enum event_type_t ctx_event_type;
2722 bool cpu_event = !!(event_type & EVENT_CPU);
2725 * If pinned groups are involved, flexible groups also need to be
2728 if (event_type & EVENT_PINNED)
2729 event_type |= EVENT_FLEXIBLE;
2731 ctx_event_type = event_type & EVENT_ALL;
2733 perf_pmu_disable(cpuctx->ctx.pmu);
2735 task_ctx_sched_out(cpuctx, task_ctx, event_type);
2738 * Decide which cpu ctx groups to schedule out based on the types
2739 * of events that caused rescheduling:
2740 * - EVENT_CPU: schedule out corresponding groups;
2741 * - EVENT_PINNED task events: schedule out EVENT_FLEXIBLE groups;
2742 * - otherwise, do nothing more.
2745 cpu_ctx_sched_out(cpuctx, ctx_event_type);
2746 else if (ctx_event_type & EVENT_PINNED)
2747 cpu_ctx_sched_out(cpuctx, EVENT_FLEXIBLE);
2749 perf_event_sched_in(cpuctx, task_ctx, current);
2750 perf_pmu_enable(cpuctx->ctx.pmu);
2753 void perf_pmu_resched(struct pmu *pmu)
2755 struct perf_cpu_context *cpuctx = this_cpu_ptr(pmu->pmu_cpu_context);
2756 struct perf_event_context *task_ctx = cpuctx->task_ctx;
2758 perf_ctx_lock(cpuctx, task_ctx);
2759 ctx_resched(cpuctx, task_ctx, EVENT_ALL|EVENT_CPU);
2760 perf_ctx_unlock(cpuctx, task_ctx);
2764 * Cross CPU call to install and enable a performance event
2766 * Very similar to remote_function() + event_function() but cannot assume that
2767 * things like ctx->is_active and cpuctx->task_ctx are set.
2769 static int __perf_install_in_context(void *info)
2771 struct perf_event *event = info;
2772 struct perf_event_context *ctx = event->ctx;
2773 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
2774 struct perf_event_context *task_ctx = cpuctx->task_ctx;
2775 bool reprogram = true;
2778 raw_spin_lock(&cpuctx->ctx.lock);
2780 raw_spin_lock(&ctx->lock);
2783 reprogram = (ctx->task == current);
2786 * If the task is running, it must be running on this CPU,
2787 * otherwise we cannot reprogram things.
2789 * If its not running, we don't care, ctx->lock will
2790 * serialize against it becoming runnable.
2792 if (task_curr(ctx->task) && !reprogram) {
2797 WARN_ON_ONCE(reprogram && cpuctx->task_ctx && cpuctx->task_ctx != ctx);
2798 } else if (task_ctx) {
2799 raw_spin_lock(&task_ctx->lock);
2802 #ifdef CONFIG_CGROUP_PERF
2803 if (event->state > PERF_EVENT_STATE_OFF && is_cgroup_event(event)) {
2805 * If the current cgroup doesn't match the event's
2806 * cgroup, we should not try to schedule it.
2808 struct perf_cgroup *cgrp = perf_cgroup_from_task(current, ctx);
2809 reprogram = cgroup_is_descendant(cgrp->css.cgroup,
2810 event->cgrp->css.cgroup);
2815 ctx_sched_out(ctx, cpuctx, EVENT_TIME);
2816 add_event_to_ctx(event, ctx);
2817 ctx_resched(cpuctx, task_ctx, get_event_type(event));
2819 add_event_to_ctx(event, ctx);
2823 perf_ctx_unlock(cpuctx, task_ctx);
2828 static bool exclusive_event_installable(struct perf_event *event,
2829 struct perf_event_context *ctx);
2832 * Attach a performance event to a context.
2834 * Very similar to event_function_call, see comment there.
2837 perf_install_in_context(struct perf_event_context *ctx,
2838 struct perf_event *event,
2841 struct task_struct *task = READ_ONCE(ctx->task);
2843 lockdep_assert_held(&ctx->mutex);
2845 WARN_ON_ONCE(!exclusive_event_installable(event, ctx));
2847 if (event->cpu != -1)
2851 * Ensures that if we can observe event->ctx, both the event and ctx
2852 * will be 'complete'. See perf_iterate_sb_cpu().
2854 smp_store_release(&event->ctx, ctx);
2857 * perf_event_attr::disabled events will not run and can be initialized
2858 * without IPI. Except when this is the first event for the context, in
2859 * that case we need the magic of the IPI to set ctx->is_active.
2861 * The IOC_ENABLE that is sure to follow the creation of a disabled
2862 * event will issue the IPI and reprogram the hardware.
2864 if (__perf_effective_state(event) == PERF_EVENT_STATE_OFF && ctx->nr_events) {
2865 raw_spin_lock_irq(&ctx->lock);
2866 if (ctx->task == TASK_TOMBSTONE) {
2867 raw_spin_unlock_irq(&ctx->lock);
2870 add_event_to_ctx(event, ctx);
2871 raw_spin_unlock_irq(&ctx->lock);
2876 cpu_function_call(cpu, __perf_install_in_context, event);
2881 * Should not happen, we validate the ctx is still alive before calling.
2883 if (WARN_ON_ONCE(task == TASK_TOMBSTONE))
2887 * Installing events is tricky because we cannot rely on ctx->is_active
2888 * to be set in case this is the nr_events 0 -> 1 transition.
2890 * Instead we use task_curr(), which tells us if the task is running.
2891 * However, since we use task_curr() outside of rq::lock, we can race
2892 * against the actual state. This means the result can be wrong.
2894 * If we get a false positive, we retry, this is harmless.
2896 * If we get a false negative, things are complicated. If we are after
2897 * perf_event_context_sched_in() ctx::lock will serialize us, and the
2898 * value must be correct. If we're before, it doesn't matter since
2899 * perf_event_context_sched_in() will program the counter.
2901 * However, this hinges on the remote context switch having observed
2902 * our task->perf_event_ctxp[] store, such that it will in fact take
2903 * ctx::lock in perf_event_context_sched_in().
2905 * We do this by task_function_call(), if the IPI fails to hit the task
2906 * we know any future context switch of task must see the
2907 * perf_event_ctpx[] store.
2911 * This smp_mb() orders the task->perf_event_ctxp[] store with the
2912 * task_cpu() load, such that if the IPI then does not find the task
2913 * running, a future context switch of that task must observe the
2918 if (!task_function_call(task, __perf_install_in_context, event))
2921 raw_spin_lock_irq(&ctx->lock);
2923 if (WARN_ON_ONCE(task == TASK_TOMBSTONE)) {
2925 * Cannot happen because we already checked above (which also
2926 * cannot happen), and we hold ctx->mutex, which serializes us
2927 * against perf_event_exit_task_context().
2929 raw_spin_unlock_irq(&ctx->lock);
2933 * If the task is not running, ctx->lock will avoid it becoming so,
2934 * thus we can safely install the event.
2936 if (task_curr(task)) {
2937 raw_spin_unlock_irq(&ctx->lock);
2940 add_event_to_ctx(event, ctx);
2941 raw_spin_unlock_irq(&ctx->lock);
2945 * Cross CPU call to enable a performance event
2947 static void __perf_event_enable(struct perf_event *event,
2948 struct perf_cpu_context *cpuctx,
2949 struct perf_event_context *ctx,
2952 struct perf_event *leader = event->group_leader;
2953 struct perf_event_context *task_ctx;
2955 if (event->state >= PERF_EVENT_STATE_INACTIVE ||
2956 event->state <= PERF_EVENT_STATE_ERROR)
2960 ctx_sched_out(ctx, cpuctx, EVENT_TIME);
2962 perf_event_set_state(event, PERF_EVENT_STATE_INACTIVE);
2963 perf_cgroup_event_enable(event, ctx);
2965 if (!ctx->is_active)
2968 if (!event_filter_match(event)) {
2969 ctx_sched_in(ctx, cpuctx, EVENT_TIME, current);
2974 * If the event is in a group and isn't the group leader,
2975 * then don't put it on unless the group is on.
2977 if (leader != event && leader->state != PERF_EVENT_STATE_ACTIVE) {
2978 ctx_sched_in(ctx, cpuctx, EVENT_TIME, current);
2982 task_ctx = cpuctx->task_ctx;
2984 WARN_ON_ONCE(task_ctx != ctx);
2986 ctx_resched(cpuctx, task_ctx, get_event_type(event));
2992 * If event->ctx is a cloned context, callers must make sure that
2993 * every task struct that event->ctx->task could possibly point to
2994 * remains valid. This condition is satisfied when called through
2995 * perf_event_for_each_child or perf_event_for_each as described
2996 * for perf_event_disable.
2998 static void _perf_event_enable(struct perf_event *event)
3000 struct perf_event_context *ctx = event->ctx;
3002 raw_spin_lock_irq(&ctx->lock);
3003 if (event->state >= PERF_EVENT_STATE_INACTIVE ||
3004 event->state < PERF_EVENT_STATE_ERROR) {
3006 raw_spin_unlock_irq(&ctx->lock);
3011 * If the event is in error state, clear that first.
3013 * That way, if we see the event in error state below, we know that it
3014 * has gone back into error state, as distinct from the task having
3015 * been scheduled away before the cross-call arrived.
3017 if (event->state == PERF_EVENT_STATE_ERROR) {
3019 * Detached SIBLING events cannot leave ERROR state.
3021 if (event->event_caps & PERF_EV_CAP_SIBLING &&
3022 event->group_leader == event)
3025 event->state = PERF_EVENT_STATE_OFF;
3027 raw_spin_unlock_irq(&ctx->lock);
3029 event_function_call(event, __perf_event_enable, NULL);
3033 * See perf_event_disable();
3035 void perf_event_enable(struct perf_event *event)
3037 struct perf_event_context *ctx;
3039 ctx = perf_event_ctx_lock(event);
3040 _perf_event_enable(event);
3041 perf_event_ctx_unlock(event, ctx);
3043 EXPORT_SYMBOL_GPL(perf_event_enable);
3045 struct stop_event_data {
3046 struct perf_event *event;
3047 unsigned int restart;
3050 static int __perf_event_stop(void *info)
3052 struct stop_event_data *sd = info;
3053 struct perf_event *event = sd->event;
3055 /* if it's already INACTIVE, do nothing */
3056 if (READ_ONCE(event->state) != PERF_EVENT_STATE_ACTIVE)
3059 /* matches smp_wmb() in event_sched_in() */
3063 * There is a window with interrupts enabled before we get here,
3064 * so we need to check again lest we try to stop another CPU's event.
3066 if (READ_ONCE(event->oncpu) != smp_processor_id())
3069 event->pmu->stop(event, PERF_EF_UPDATE);
3072 * May race with the actual stop (through perf_pmu_output_stop()),
3073 * but it is only used for events with AUX ring buffer, and such
3074 * events will refuse to restart because of rb::aux_mmap_count==0,
3075 * see comments in perf_aux_output_begin().
3077 * Since this is happening on an event-local CPU, no trace is lost
3081 event->pmu->start(event, 0);
3086 static int perf_event_stop(struct perf_event *event, int restart)
3088 struct stop_event_data sd = {
3095 if (READ_ONCE(event->state) != PERF_EVENT_STATE_ACTIVE)
3098 /* matches smp_wmb() in event_sched_in() */
3102 * We only want to restart ACTIVE events, so if the event goes
3103 * inactive here (event->oncpu==-1), there's nothing more to do;
3104 * fall through with ret==-ENXIO.
3106 ret = cpu_function_call(READ_ONCE(event->oncpu),
3107 __perf_event_stop, &sd);
3108 } while (ret == -EAGAIN);
3114 * In order to contain the amount of racy and tricky in the address filter
3115 * configuration management, it is a two part process:
3117 * (p1) when userspace mappings change as a result of (1) or (2) or (3) below,
3118 * we update the addresses of corresponding vmas in
3119 * event::addr_filter_ranges array and bump the event::addr_filters_gen;
3120 * (p2) when an event is scheduled in (pmu::add), it calls
3121 * perf_event_addr_filters_sync() which calls pmu::addr_filters_sync()
3122 * if the generation has changed since the previous call.
3124 * If (p1) happens while the event is active, we restart it to force (p2).
3126 * (1) perf_addr_filters_apply(): adjusting filters' offsets based on
3127 * pre-existing mappings, called once when new filters arrive via SET_FILTER
3129 * (2) perf_addr_filters_adjust(): adjusting filters' offsets based on newly
3130 * registered mapping, called for every new mmap(), with mm::mmap_lock down
3132 * (3) perf_event_addr_filters_exec(): clearing filters' offsets in the process
3135 void perf_event_addr_filters_sync(struct perf_event *event)
3137 struct perf_addr_filters_head *ifh = perf_event_addr_filters(event);
3139 if (!has_addr_filter(event))
3142 raw_spin_lock(&ifh->lock);
3143 if (event->addr_filters_gen != event->hw.addr_filters_gen) {
3144 event->pmu->addr_filters_sync(event);
3145 event->hw.addr_filters_gen = event->addr_filters_gen;
3147 raw_spin_unlock(&ifh->lock);
3149 EXPORT_SYMBOL_GPL(perf_event_addr_filters_sync);
3151 static int _perf_event_refresh(struct perf_event *event, int refresh)
3154 * not supported on inherited events
3156 if (event->attr.inherit || !is_sampling_event(event))
3159 atomic_add(refresh, &event->event_limit);
3160 _perf_event_enable(event);
3166 * See perf_event_disable()
3168 int perf_event_refresh(struct perf_event *event, int refresh)
3170 struct perf_event_context *ctx;
3173 ctx = perf_event_ctx_lock(event);
3174 ret = _perf_event_refresh(event, refresh);
3175 perf_event_ctx_unlock(event, ctx);
3179 EXPORT_SYMBOL_GPL(perf_event_refresh);
3181 static int perf_event_modify_breakpoint(struct perf_event *bp,
3182 struct perf_event_attr *attr)
3186 _perf_event_disable(bp);
3188 err = modify_user_hw_breakpoint_check(bp, attr, true);
3190 if (!bp->attr.disabled)
3191 _perf_event_enable(bp);
3196 static int perf_event_modify_attr(struct perf_event *event,
3197 struct perf_event_attr *attr)
3199 int (*func)(struct perf_event *, struct perf_event_attr *);
3200 struct perf_event *child;
3203 if (event->attr.type != attr->type)
3206 switch (event->attr.type) {
3207 case PERF_TYPE_BREAKPOINT:
3208 func = perf_event_modify_breakpoint;
3211 /* Place holder for future additions. */
3215 WARN_ON_ONCE(event->ctx->parent_ctx);
3217 mutex_lock(&event->child_mutex);
3218 err = func(event, attr);
3221 list_for_each_entry(child, &event->child_list, child_list) {
3222 err = func(child, attr);
3227 mutex_unlock(&event->child_mutex);
3231 static void ctx_sched_out(struct perf_event_context *ctx,
3232 struct perf_cpu_context *cpuctx,
3233 enum event_type_t event_type)
3235 struct perf_event *event, *tmp;
3236 int is_active = ctx->is_active;
3238 lockdep_assert_held(&ctx->lock);
3240 if (likely(!ctx->nr_events)) {
3242 * See __perf_remove_from_context().
3244 WARN_ON_ONCE(ctx->is_active);
3246 WARN_ON_ONCE(cpuctx->task_ctx);
3250 ctx->is_active &= ~event_type;
3251 if (!(ctx->is_active & EVENT_ALL))
3255 WARN_ON_ONCE(cpuctx->task_ctx != ctx);
3256 if (!ctx->is_active)
3257 cpuctx->task_ctx = NULL;
3261 * Always update time if it was set; not only when it changes.
3262 * Otherwise we can 'forget' to update time for any but the last
3263 * context we sched out. For example:
3265 * ctx_sched_out(.event_type = EVENT_FLEXIBLE)
3266 * ctx_sched_out(.event_type = EVENT_PINNED)
3268 * would only update time for the pinned events.
3270 if (is_active & EVENT_TIME) {
3271 /* update (and stop) ctx time */
3272 update_context_time(ctx);
3273 update_cgrp_time_from_cpuctx(cpuctx);
3276 is_active ^= ctx->is_active; /* changed bits */
3278 if (!ctx->nr_active || !(is_active & EVENT_ALL))
3281 perf_pmu_disable(ctx->pmu);
3282 if (is_active & EVENT_PINNED) {
3283 list_for_each_entry_safe(event, tmp, &ctx->pinned_active, active_list)
3284 group_sched_out(event, cpuctx, ctx);
3287 if (is_active & EVENT_FLEXIBLE) {
3288 list_for_each_entry_safe(event, tmp, &ctx->flexible_active, active_list)
3289 group_sched_out(event, cpuctx, ctx);
3292 * Since we cleared EVENT_FLEXIBLE, also clear
3293 * rotate_necessary, is will be reset by
3294 * ctx_flexible_sched_in() when needed.
3296 ctx->rotate_necessary = 0;
3298 perf_pmu_enable(ctx->pmu);
3302 * Test whether two contexts are equivalent, i.e. whether they have both been
3303 * cloned from the same version of the same context.
3305 * Equivalence is measured using a generation number in the context that is
3306 * incremented on each modification to it; see unclone_ctx(), list_add_event()
3307 * and list_del_event().
3309 static int context_equiv(struct perf_event_context *ctx1,
3310 struct perf_event_context *ctx2)
3312 lockdep_assert_held(&ctx1->lock);
3313 lockdep_assert_held(&ctx2->lock);
3315 /* Pinning disables the swap optimization */
3316 if (ctx1->pin_count || ctx2->pin_count)
3319 /* If ctx1 is the parent of ctx2 */
3320 if (ctx1 == ctx2->parent_ctx && ctx1->generation == ctx2->parent_gen)
3323 /* If ctx2 is the parent of ctx1 */
3324 if (ctx1->parent_ctx == ctx2 && ctx1->parent_gen == ctx2->generation)
3328 * If ctx1 and ctx2 have the same parent; we flatten the parent
3329 * hierarchy, see perf_event_init_context().
3331 if (ctx1->parent_ctx && ctx1->parent_ctx == ctx2->parent_ctx &&
3332 ctx1->parent_gen == ctx2->parent_gen)
3339 static void __perf_event_sync_stat(struct perf_event *event,
3340 struct perf_event *next_event)
3344 if (!event->attr.inherit_stat)
3348 * Update the event value, we cannot use perf_event_read()
3349 * because we're in the middle of a context switch and have IRQs
3350 * disabled, which upsets smp_call_function_single(), however
3351 * we know the event must be on the current CPU, therefore we
3352 * don't need to use it.
3354 if (event->state == PERF_EVENT_STATE_ACTIVE)
3355 event->pmu->read(event);
3357 perf_event_update_time(event);
3360 * In order to keep per-task stats reliable we need to flip the event
3361 * values when we flip the contexts.
3363 value = local64_read(&next_event->count);
3364 value = local64_xchg(&event->count, value);
3365 local64_set(&next_event->count, value);
3367 swap(event->total_time_enabled, next_event->total_time_enabled);
3368 swap(event->total_time_running, next_event->total_time_running);
3371 * Since we swizzled the values, update the user visible data too.
3373 perf_event_update_userpage(event);
3374 perf_event_update_userpage(next_event);
3377 static void perf_event_sync_stat(struct perf_event_context *ctx,
3378 struct perf_event_context *next_ctx)
3380 struct perf_event *event, *next_event;
3385 update_context_time(ctx);
3387 event = list_first_entry(&ctx->event_list,
3388 struct perf_event, event_entry);
3390 next_event = list_first_entry(&next_ctx->event_list,
3391 struct perf_event, event_entry);
3393 while (&event->event_entry != &ctx->event_list &&
3394 &next_event->event_entry != &next_ctx->event_list) {
3396 __perf_event_sync_stat(event, next_event);
3398 event = list_next_entry(event, event_entry);
3399 next_event = list_next_entry(next_event, event_entry);
3403 static void perf_event_context_sched_out(struct task_struct *task, int ctxn,
3404 struct task_struct *next)
3406 struct perf_event_context *ctx = task->perf_event_ctxp[ctxn];
3407 struct perf_event_context *next_ctx;
3408 struct perf_event_context *parent, *next_parent;
3409 struct perf_cpu_context *cpuctx;
3417 cpuctx = __get_cpu_context(ctx);
3418 if (!cpuctx->task_ctx)
3422 next_ctx = next->perf_event_ctxp[ctxn];
3426 parent = rcu_dereference(ctx->parent_ctx);
3427 next_parent = rcu_dereference(next_ctx->parent_ctx);
3429 /* If neither context have a parent context; they cannot be clones. */
3430 if (!parent && !next_parent)
3433 if (next_parent == ctx || next_ctx == parent || next_parent == parent) {
3435 * Looks like the two contexts are clones, so we might be
3436 * able to optimize the context switch. We lock both
3437 * contexts and check that they are clones under the
3438 * lock (including re-checking that neither has been
3439 * uncloned in the meantime). It doesn't matter which
3440 * order we take the locks because no other cpu could
3441 * be trying to lock both of these tasks.
3443 raw_spin_lock(&ctx->lock);
3444 raw_spin_lock_nested(&next_ctx->lock, SINGLE_DEPTH_NESTING);
3445 if (context_equiv(ctx, next_ctx)) {
3447 WRITE_ONCE(ctx->task, next);
3448 WRITE_ONCE(next_ctx->task, task);
3450 perf_pmu_disable(pmu);
3452 if (cpuctx->sched_cb_usage && pmu->sched_task)
3453 pmu->sched_task(ctx, false);
3456 * PMU specific parts of task perf context can require
3457 * additional synchronization. As an example of such
3458 * synchronization see implementation details of Intel
3459 * LBR call stack data profiling;
3461 if (pmu->swap_task_ctx)
3462 pmu->swap_task_ctx(ctx, next_ctx);
3464 swap(ctx->task_ctx_data, next_ctx->task_ctx_data);
3466 perf_pmu_enable(pmu);
3469 * RCU_INIT_POINTER here is safe because we've not
3470 * modified the ctx and the above modification of
3471 * ctx->task and ctx->task_ctx_data are immaterial
3472 * since those values are always verified under
3473 * ctx->lock which we're now holding.
3475 RCU_INIT_POINTER(task->perf_event_ctxp[ctxn], next_ctx);
3476 RCU_INIT_POINTER(next->perf_event_ctxp[ctxn], ctx);
3480 perf_event_sync_stat(ctx, next_ctx);
3482 raw_spin_unlock(&next_ctx->lock);
3483 raw_spin_unlock(&ctx->lock);
3489 raw_spin_lock(&ctx->lock);
3490 perf_pmu_disable(pmu);
3492 if (cpuctx->sched_cb_usage && pmu->sched_task)
3493 pmu->sched_task(ctx, false);
3494 task_ctx_sched_out(cpuctx, ctx, EVENT_ALL);
3496 perf_pmu_enable(pmu);
3497 raw_spin_unlock(&ctx->lock);
3501 static DEFINE_PER_CPU(struct list_head, sched_cb_list);
3503 void perf_sched_cb_dec(struct pmu *pmu)
3505 struct perf_cpu_context *cpuctx = this_cpu_ptr(pmu->pmu_cpu_context);
3507 this_cpu_dec(perf_sched_cb_usages);
3509 if (!--cpuctx->sched_cb_usage)
3510 list_del(&cpuctx->sched_cb_entry);
3514 void perf_sched_cb_inc(struct pmu *pmu)
3516 struct perf_cpu_context *cpuctx = this_cpu_ptr(pmu->pmu_cpu_context);
3518 if (!cpuctx->sched_cb_usage++)
3519 list_add(&cpuctx->sched_cb_entry, this_cpu_ptr(&sched_cb_list));
3521 this_cpu_inc(perf_sched_cb_usages);
3525 * This function provides the context switch callback to the lower code
3526 * layer. It is invoked ONLY when the context switch callback is enabled.
3528 * This callback is relevant even to per-cpu events; for example multi event
3529 * PEBS requires this to provide PID/TID information. This requires we flush
3530 * all queued PEBS records before we context switch to a new task.
3532 static void __perf_pmu_sched_task(struct perf_cpu_context *cpuctx, bool sched_in)
3536 pmu = cpuctx->ctx.pmu; /* software PMUs will not have sched_task */
3538 if (WARN_ON_ONCE(!pmu->sched_task))
3541 perf_ctx_lock(cpuctx, cpuctx->task_ctx);
3542 perf_pmu_disable(pmu);
3544 pmu->sched_task(cpuctx->task_ctx, sched_in);
3546 perf_pmu_enable(pmu);
3547 perf_ctx_unlock(cpuctx, cpuctx->task_ctx);
3550 static void perf_pmu_sched_task(struct task_struct *prev,
3551 struct task_struct *next,
3554 struct perf_cpu_context *cpuctx;
3559 list_for_each_entry(cpuctx, this_cpu_ptr(&sched_cb_list), sched_cb_entry) {
3560 /* will be handled in perf_event_context_sched_in/out */
3561 if (cpuctx->task_ctx)
3564 __perf_pmu_sched_task(cpuctx, sched_in);
3568 static void perf_event_switch(struct task_struct *task,
3569 struct task_struct *next_prev, bool sched_in);
3571 #define for_each_task_context_nr(ctxn) \
3572 for ((ctxn) = 0; (ctxn) < perf_nr_task_contexts; (ctxn)++)
3575 * Called from scheduler to remove the events of the current task,
3576 * with interrupts disabled.
3578 * We stop each event and update the event value in event->count.
3580 * This does not protect us against NMI, but disable()
3581 * sets the disabled bit in the control field of event _before_
3582 * accessing the event control register. If a NMI hits, then it will
3583 * not restart the event.
3585 void __perf_event_task_sched_out(struct task_struct *task,
3586 struct task_struct *next)
3590 if (__this_cpu_read(perf_sched_cb_usages))
3591 perf_pmu_sched_task(task, next, false);
3593 if (atomic_read(&nr_switch_events))
3594 perf_event_switch(task, next, false);
3596 for_each_task_context_nr(ctxn)
3597 perf_event_context_sched_out(task, ctxn, next);
3600 * if cgroup events exist on this CPU, then we need
3601 * to check if we have to switch out PMU state.
3602 * cgroup event are system-wide mode only
3604 if (atomic_read(this_cpu_ptr(&perf_cgroup_events)))
3605 perf_cgroup_sched_out(task, next);
3609 * Called with IRQs disabled
3611 static void cpu_ctx_sched_out(struct perf_cpu_context *cpuctx,
3612 enum event_type_t event_type)
3614 ctx_sched_out(&cpuctx->ctx, cpuctx, event_type);
3617 static bool perf_less_group_idx(const void *l, const void *r)
3619 const struct perf_event *le = *(const struct perf_event **)l;
3620 const struct perf_event *re = *(const struct perf_event **)r;
3622 return le->group_index < re->group_index;
3625 static void swap_ptr(void *l, void *r)
3627 void **lp = l, **rp = r;
3632 static const struct min_heap_callbacks perf_min_heap = {
3633 .elem_size = sizeof(struct perf_event *),
3634 .less = perf_less_group_idx,
3638 static void __heap_add(struct min_heap *heap, struct perf_event *event)
3640 struct perf_event **itrs = heap->data;
3643 itrs[heap->nr] = event;
3648 static noinline int visit_groups_merge(struct perf_cpu_context *cpuctx,
3649 struct perf_event_groups *groups, int cpu,
3650 int (*func)(struct perf_event *, void *),
3653 #ifdef CONFIG_CGROUP_PERF
3654 struct cgroup_subsys_state *css = NULL;
3656 /* Space for per CPU and/or any CPU event iterators. */
3657 struct perf_event *itrs[2];
3658 struct min_heap event_heap;
3659 struct perf_event **evt;
3663 event_heap = (struct min_heap){
3664 .data = cpuctx->heap,
3666 .size = cpuctx->heap_size,
3669 lockdep_assert_held(&cpuctx->ctx.lock);
3671 #ifdef CONFIG_CGROUP_PERF
3673 css = &cpuctx->cgrp->css;
3676 event_heap = (struct min_heap){
3679 .size = ARRAY_SIZE(itrs),
3681 /* Events not within a CPU context may be on any CPU. */
3682 __heap_add(&event_heap, perf_event_groups_first(groups, -1, NULL));
3684 evt = event_heap.data;
3686 __heap_add(&event_heap, perf_event_groups_first(groups, cpu, NULL));
3688 #ifdef CONFIG_CGROUP_PERF
3689 for (; css; css = css->parent)
3690 __heap_add(&event_heap, perf_event_groups_first(groups, cpu, css->cgroup));
3693 min_heapify_all(&event_heap, &perf_min_heap);
3695 while (event_heap.nr) {
3696 ret = func(*evt, data);
3700 *evt = perf_event_groups_next(*evt);
3702 min_heapify(&event_heap, 0, &perf_min_heap);
3704 min_heap_pop(&event_heap, &perf_min_heap);
3710 static int merge_sched_in(struct perf_event *event, void *data)
3712 struct perf_event_context *ctx = event->ctx;
3713 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
3714 int *can_add_hw = data;
3716 if (event->state <= PERF_EVENT_STATE_OFF)
3719 if (!event_filter_match(event))
3722 if (group_can_go_on(event, cpuctx, *can_add_hw)) {
3723 if (!group_sched_in(event, cpuctx, ctx))
3724 list_add_tail(&event->active_list, get_event_list(event));
3727 if (event->state == PERF_EVENT_STATE_INACTIVE) {
3728 if (event->attr.pinned) {
3729 perf_cgroup_event_disable(event, ctx);
3730 perf_event_set_state(event, PERF_EVENT_STATE_ERROR);
3734 ctx->rotate_necessary = 1;
3735 perf_mux_hrtimer_restart(cpuctx);
3742 ctx_pinned_sched_in(struct perf_event_context *ctx,
3743 struct perf_cpu_context *cpuctx)
3747 if (ctx != &cpuctx->ctx)
3750 visit_groups_merge(cpuctx, &ctx->pinned_groups,
3752 merge_sched_in, &can_add_hw);
3756 ctx_flexible_sched_in(struct perf_event_context *ctx,
3757 struct perf_cpu_context *cpuctx)
3761 if (ctx != &cpuctx->ctx)
3764 visit_groups_merge(cpuctx, &ctx->flexible_groups,
3766 merge_sched_in, &can_add_hw);
3770 ctx_sched_in(struct perf_event_context *ctx,
3771 struct perf_cpu_context *cpuctx,
3772 enum event_type_t event_type,
3773 struct task_struct *task)
3775 int is_active = ctx->is_active;
3778 lockdep_assert_held(&ctx->lock);
3780 if (likely(!ctx->nr_events))
3783 ctx->is_active |= (event_type | EVENT_TIME);
3786 cpuctx->task_ctx = ctx;
3788 WARN_ON_ONCE(cpuctx->task_ctx != ctx);
3791 is_active ^= ctx->is_active; /* changed bits */
3793 if (is_active & EVENT_TIME) {
3794 /* start ctx time */
3796 ctx->timestamp = now;
3797 perf_cgroup_set_timestamp(task, ctx);
3801 * First go through the list and put on any pinned groups
3802 * in order to give them the best chance of going on.
3804 if (is_active & EVENT_PINNED)
3805 ctx_pinned_sched_in(ctx, cpuctx);
3807 /* Then walk through the lower prio flexible groups */
3808 if (is_active & EVENT_FLEXIBLE)
3809 ctx_flexible_sched_in(ctx, cpuctx);
3812 static void cpu_ctx_sched_in(struct perf_cpu_context *cpuctx,
3813 enum event_type_t event_type,
3814 struct task_struct *task)
3816 struct perf_event_context *ctx = &cpuctx->ctx;
3818 ctx_sched_in(ctx, cpuctx, event_type, task);
3821 static void perf_event_context_sched_in(struct perf_event_context *ctx,
3822 struct task_struct *task)
3824 struct perf_cpu_context *cpuctx;
3827 cpuctx = __get_cpu_context(ctx);
3830 * HACK: for HETEROGENEOUS the task context might have switched to a
3831 * different PMU, force (re)set the context,
3833 pmu = ctx->pmu = cpuctx->ctx.pmu;
3835 if (cpuctx->task_ctx == ctx) {
3836 if (cpuctx->sched_cb_usage)
3837 __perf_pmu_sched_task(cpuctx, true);
3841 perf_ctx_lock(cpuctx, ctx);
3843 * We must check ctx->nr_events while holding ctx->lock, such
3844 * that we serialize against perf_install_in_context().
3846 if (!ctx->nr_events)
3849 perf_pmu_disable(pmu);
3851 * We want to keep the following priority order:
3852 * cpu pinned (that don't need to move), task pinned,
3853 * cpu flexible, task flexible.
3855 * However, if task's ctx is not carrying any pinned
3856 * events, no need to flip the cpuctx's events around.
3858 if (!RB_EMPTY_ROOT(&ctx->pinned_groups.tree))
3859 cpu_ctx_sched_out(cpuctx, EVENT_FLEXIBLE);
3860 perf_event_sched_in(cpuctx, ctx, task);
3862 if (cpuctx->sched_cb_usage && pmu->sched_task)
3863 pmu->sched_task(cpuctx->task_ctx, true);
3865 perf_pmu_enable(pmu);
3868 perf_ctx_unlock(cpuctx, ctx);
3872 * Called from scheduler to add the events of the current task
3873 * with interrupts disabled.
3875 * We restore the event value and then enable it.
3877 * This does not protect us against NMI, but enable()
3878 * sets the enabled bit in the control field of event _before_
3879 * accessing the event control register. If a NMI hits, then it will
3880 * keep the event running.
3882 void __perf_event_task_sched_in(struct task_struct *prev,
3883 struct task_struct *task)
3885 struct perf_event_context *ctx;
3889 * If cgroup events exist on this CPU, then we need to check if we have
3890 * to switch in PMU state; cgroup event are system-wide mode only.
3892 * Since cgroup events are CPU events, we must schedule these in before
3893 * we schedule in the task events.
3895 if (atomic_read(this_cpu_ptr(&perf_cgroup_events)))
3896 perf_cgroup_sched_in(prev, task);
3898 for_each_task_context_nr(ctxn) {
3899 ctx = task->perf_event_ctxp[ctxn];
3903 perf_event_context_sched_in(ctx, task);
3906 if (atomic_read(&nr_switch_events))
3907 perf_event_switch(task, prev, true);
3909 if (__this_cpu_read(perf_sched_cb_usages))
3910 perf_pmu_sched_task(prev, task, true);
3913 static u64 perf_calculate_period(struct perf_event *event, u64 nsec, u64 count)
3915 u64 frequency = event->attr.sample_freq;
3916 u64 sec = NSEC_PER_SEC;
3917 u64 divisor, dividend;
3919 int count_fls, nsec_fls, frequency_fls, sec_fls;
3921 count_fls = fls64(count);
3922 nsec_fls = fls64(nsec);
3923 frequency_fls = fls64(frequency);
3927 * We got @count in @nsec, with a target of sample_freq HZ
3928 * the target period becomes:
3931 * period = -------------------
3932 * @nsec * sample_freq
3937 * Reduce accuracy by one bit such that @a and @b converge
3938 * to a similar magnitude.
3940 #define REDUCE_FLS(a, b) \
3942 if (a##_fls > b##_fls) { \
3952 * Reduce accuracy until either term fits in a u64, then proceed with
3953 * the other, so that finally we can do a u64/u64 division.
3955 while (count_fls + sec_fls > 64 && nsec_fls + frequency_fls > 64) {
3956 REDUCE_FLS(nsec, frequency);
3957 REDUCE_FLS(sec, count);
3960 if (count_fls + sec_fls > 64) {
3961 divisor = nsec * frequency;
3963 while (count_fls + sec_fls > 64) {
3964 REDUCE_FLS(count, sec);
3968 dividend = count * sec;
3970 dividend = count * sec;
3972 while (nsec_fls + frequency_fls > 64) {
3973 REDUCE_FLS(nsec, frequency);
3977 divisor = nsec * frequency;
3983 return div64_u64(dividend, divisor);
3986 static DEFINE_PER_CPU(int, perf_throttled_count);
3987 static DEFINE_PER_CPU(u64, perf_throttled_seq);
3989 static void perf_adjust_period(struct perf_event *event, u64 nsec, u64 count, bool disable)
3991 struct hw_perf_event *hwc = &event->hw;
3992 s64 period, sample_period;
3995 period = perf_calculate_period(event, nsec, count);
3997 delta = (s64)(period - hwc->sample_period);
3998 delta = (delta + 7) / 8; /* low pass filter */
4000 sample_period = hwc->sample_period + delta;
4005 hwc->sample_period = sample_period;
4007 if (local64_read(&hwc->period_left) > 8*sample_period) {
4009 event->pmu->stop(event, PERF_EF_UPDATE);
4011 local64_set(&hwc->period_left, 0);
4014 event->pmu->start(event, PERF_EF_RELOAD);
4019 * combine freq adjustment with unthrottling to avoid two passes over the
4020 * events. At the same time, make sure, having freq events does not change
4021 * the rate of unthrottling as that would introduce bias.
4023 static void perf_adjust_freq_unthr_context(struct perf_event_context *ctx,
4026 struct perf_event *event;
4027 struct hw_perf_event *hwc;
4028 u64 now, period = TICK_NSEC;
4032 * only need to iterate over all events iff:
4033 * - context have events in frequency mode (needs freq adjust)
4034 * - there are events to unthrottle on this cpu
4036 if (!(ctx->nr_freq || needs_unthr))
4039 raw_spin_lock(&ctx->lock);
4040 perf_pmu_disable(ctx->pmu);
4042 list_for_each_entry_rcu(event, &ctx->event_list, event_entry) {
4043 if (event->state != PERF_EVENT_STATE_ACTIVE)
4046 if (!event_filter_match(event))
4049 perf_pmu_disable(event->pmu);
4053 if (hwc->interrupts == MAX_INTERRUPTS) {
4054 hwc->interrupts = 0;
4055 perf_log_throttle(event, 1);
4056 event->pmu->start(event, 0);
4059 if (!event->attr.freq || !event->attr.sample_freq)
4063 * stop the event and update event->count
4065 event->pmu->stop(event, PERF_EF_UPDATE);
4067 now = local64_read(&event->count);
4068 delta = now - hwc->freq_count_stamp;
4069 hwc->freq_count_stamp = now;
4073 * reload only if value has changed
4074 * we have stopped the event so tell that
4075 * to perf_adjust_period() to avoid stopping it
4079 perf_adjust_period(event, period, delta, false);
4081 event->pmu->start(event, delta > 0 ? PERF_EF_RELOAD : 0);
4083 perf_pmu_enable(event->pmu);
4086 perf_pmu_enable(ctx->pmu);
4087 raw_spin_unlock(&ctx->lock);
4091 * Move @event to the tail of the @ctx's elegible events.
4093 static void rotate_ctx(struct perf_event_context *ctx, struct perf_event *event)
4096 * Rotate the first entry last of non-pinned groups. Rotation might be
4097 * disabled by the inheritance code.
4099 if (ctx->rotate_disable)
4102 perf_event_groups_delete(&ctx->flexible_groups, event);
4103 perf_event_groups_insert(&ctx->flexible_groups, event);
4106 /* pick an event from the flexible_groups to rotate */
4107 static inline struct perf_event *
4108 ctx_event_to_rotate(struct perf_event_context *ctx)
4110 struct perf_event *event;
4112 /* pick the first active flexible event */
4113 event = list_first_entry_or_null(&ctx->flexible_active,
4114 struct perf_event, active_list);
4116 /* if no active flexible event, pick the first event */
4118 event = rb_entry_safe(rb_first(&ctx->flexible_groups.tree),
4119 typeof(*event), group_node);
4123 * Unconditionally clear rotate_necessary; if ctx_flexible_sched_in()
4124 * finds there are unschedulable events, it will set it again.
4126 ctx->rotate_necessary = 0;
4131 static bool perf_rotate_context(struct perf_cpu_context *cpuctx)
4133 struct perf_event *cpu_event = NULL, *task_event = NULL;
4134 struct perf_event_context *task_ctx = NULL;
4135 int cpu_rotate, task_rotate;
4138 * Since we run this from IRQ context, nobody can install new
4139 * events, thus the event count values are stable.
4142 cpu_rotate = cpuctx->ctx.rotate_necessary;
4143 task_ctx = cpuctx->task_ctx;
4144 task_rotate = task_ctx ? task_ctx->rotate_necessary : 0;
4146 if (!(cpu_rotate || task_rotate))
4149 perf_ctx_lock(cpuctx, cpuctx->task_ctx);
4150 perf_pmu_disable(cpuctx->ctx.pmu);
4153 task_event = ctx_event_to_rotate(task_ctx);
4155 cpu_event = ctx_event_to_rotate(&cpuctx->ctx);
4158 * As per the order given at ctx_resched() first 'pop' task flexible
4159 * and then, if needed CPU flexible.
4161 if (task_event || (task_ctx && cpu_event))
4162 ctx_sched_out(task_ctx, cpuctx, EVENT_FLEXIBLE);
4164 cpu_ctx_sched_out(cpuctx, EVENT_FLEXIBLE);
4167 rotate_ctx(task_ctx, task_event);
4169 rotate_ctx(&cpuctx->ctx, cpu_event);
4171 perf_event_sched_in(cpuctx, task_ctx, current);
4173 perf_pmu_enable(cpuctx->ctx.pmu);
4174 perf_ctx_unlock(cpuctx, cpuctx->task_ctx);
4179 void perf_event_task_tick(void)
4181 struct list_head *head = this_cpu_ptr(&active_ctx_list);
4182 struct perf_event_context *ctx, *tmp;
4185 lockdep_assert_irqs_disabled();
4187 __this_cpu_inc(perf_throttled_seq);
4188 throttled = __this_cpu_xchg(perf_throttled_count, 0);
4189 tick_dep_clear_cpu(smp_processor_id(), TICK_DEP_BIT_PERF_EVENTS);
4191 list_for_each_entry_safe(ctx, tmp, head, active_ctx_list)
4192 perf_adjust_freq_unthr_context(ctx, throttled);
4195 static int event_enable_on_exec(struct perf_event *event,
4196 struct perf_event_context *ctx)
4198 if (!event->attr.enable_on_exec)
4201 event->attr.enable_on_exec = 0;
4202 if (event->state >= PERF_EVENT_STATE_INACTIVE)
4205 perf_event_set_state(event, PERF_EVENT_STATE_INACTIVE);
4211 * Enable all of a task's events that have been marked enable-on-exec.
4212 * This expects task == current.
4214 static void perf_event_enable_on_exec(int ctxn)
4216 struct perf_event_context *ctx, *clone_ctx = NULL;
4217 enum event_type_t event_type = 0;
4218 struct perf_cpu_context *cpuctx;
4219 struct perf_event *event;
4220 unsigned long flags;
4223 local_irq_save(flags);
4224 ctx = current->perf_event_ctxp[ctxn];
4225 if (!ctx || !ctx->nr_events)
4228 cpuctx = __get_cpu_context(ctx);
4229 perf_ctx_lock(cpuctx, ctx);
4230 ctx_sched_out(ctx, cpuctx, EVENT_TIME);
4231 list_for_each_entry(event, &ctx->event_list, event_entry) {
4232 enabled |= event_enable_on_exec(event, ctx);
4233 event_type |= get_event_type(event);
4237 * Unclone and reschedule this context if we enabled any event.
4240 clone_ctx = unclone_ctx(ctx);
4241 ctx_resched(cpuctx, ctx, event_type);
4243 ctx_sched_in(ctx, cpuctx, EVENT_TIME, current);
4245 perf_ctx_unlock(cpuctx, ctx);
4248 local_irq_restore(flags);
4254 static void perf_remove_from_owner(struct perf_event *event);
4255 static void perf_event_exit_event(struct perf_event *event,
4256 struct perf_event_context *ctx);
4259 * Removes all events from the current task that have been marked
4260 * remove-on-exec, and feeds their values back to parent events.
4262 static void perf_event_remove_on_exec(int ctxn)
4264 struct perf_event_context *ctx, *clone_ctx = NULL;
4265 struct perf_event *event, *next;
4266 LIST_HEAD(free_list);
4267 unsigned long flags;
4268 bool modified = false;
4270 ctx = perf_pin_task_context(current, ctxn);
4274 mutex_lock(&ctx->mutex);
4276 if (WARN_ON_ONCE(ctx->task != current))
4279 list_for_each_entry_safe(event, next, &ctx->event_list, event_entry) {
4280 if (!event->attr.remove_on_exec)
4283 if (!is_kernel_event(event))
4284 perf_remove_from_owner(event);
4288 perf_event_exit_event(event, ctx);
4291 raw_spin_lock_irqsave(&ctx->lock, flags);
4293 clone_ctx = unclone_ctx(ctx);
4295 raw_spin_unlock_irqrestore(&ctx->lock, flags);
4298 mutex_unlock(&ctx->mutex);
4305 struct perf_read_data {
4306 struct perf_event *event;
4311 static int __perf_event_read_cpu(struct perf_event *event, int event_cpu)
4313 u16 local_pkg, event_pkg;
4315 if (event->group_caps & PERF_EV_CAP_READ_ACTIVE_PKG) {
4316 int local_cpu = smp_processor_id();
4318 event_pkg = topology_physical_package_id(event_cpu);
4319 local_pkg = topology_physical_package_id(local_cpu);
4321 if (event_pkg == local_pkg)
4329 * Cross CPU call to read the hardware event
4331 static void __perf_event_read(void *info)
4333 struct perf_read_data *data = info;
4334 struct perf_event *sub, *event = data->event;
4335 struct perf_event_context *ctx = event->ctx;
4336 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
4337 struct pmu *pmu = event->pmu;
4340 * If this is a task context, we need to check whether it is
4341 * the current task context of this cpu. If not it has been
4342 * scheduled out before the smp call arrived. In that case
4343 * event->count would have been updated to a recent sample
4344 * when the event was scheduled out.
4346 if (ctx->task && cpuctx->task_ctx != ctx)
4349 raw_spin_lock(&ctx->lock);
4350 if (ctx->is_active & EVENT_TIME) {
4351 update_context_time(ctx);
4352 update_cgrp_time_from_event(event);
4355 perf_event_update_time(event);
4357 perf_event_update_sibling_time(event);
4359 if (event->state != PERF_EVENT_STATE_ACTIVE)
4368 pmu->start_txn(pmu, PERF_PMU_TXN_READ);
4372 for_each_sibling_event(sub, event) {
4373 if (sub->state == PERF_EVENT_STATE_ACTIVE) {
4375 * Use sibling's PMU rather than @event's since
4376 * sibling could be on different (eg: software) PMU.
4378 sub->pmu->read(sub);
4382 data->ret = pmu->commit_txn(pmu);
4385 raw_spin_unlock(&ctx->lock);
4388 static inline u64 perf_event_count(struct perf_event *event)
4390 return local64_read(&event->count) + atomic64_read(&event->child_count);
4394 * NMI-safe method to read a local event, that is an event that
4396 * - either for the current task, or for this CPU
4397 * - does not have inherit set, for inherited task events
4398 * will not be local and we cannot read them atomically
4399 * - must not have a pmu::count method
4401 int perf_event_read_local(struct perf_event *event, u64 *value,
4402 u64 *enabled, u64 *running)
4404 unsigned long flags;
4408 * Disabling interrupts avoids all counter scheduling (context
4409 * switches, timer based rotation and IPIs).
4411 local_irq_save(flags);
4414 * It must not be an event with inherit set, we cannot read
4415 * all child counters from atomic context.
4417 if (event->attr.inherit) {
4422 /* If this is a per-task event, it must be for current */
4423 if ((event->attach_state & PERF_ATTACH_TASK) &&
4424 event->hw.target != current) {
4429 /* If this is a per-CPU event, it must be for this CPU */
4430 if (!(event->attach_state & PERF_ATTACH_TASK) &&
4431 event->cpu != smp_processor_id()) {
4436 /* If this is a pinned event it must be running on this CPU */
4437 if (event->attr.pinned && event->oncpu != smp_processor_id()) {
4443 * If the event is currently on this CPU, its either a per-task event,
4444 * or local to this CPU. Furthermore it means its ACTIVE (otherwise
4447 if (event->oncpu == smp_processor_id())
4448 event->pmu->read(event);
4450 *value = local64_read(&event->count);
4451 if (enabled || running) {
4452 u64 now = event->shadow_ctx_time + perf_clock();
4453 u64 __enabled, __running;
4455 __perf_update_times(event, now, &__enabled, &__running);
4457 *enabled = __enabled;
4459 *running = __running;
4462 local_irq_restore(flags);
4467 static int perf_event_read(struct perf_event *event, bool group)
4469 enum perf_event_state state = READ_ONCE(event->state);
4470 int event_cpu, ret = 0;
4473 * If event is enabled and currently active on a CPU, update the
4474 * value in the event structure:
4477 if (state == PERF_EVENT_STATE_ACTIVE) {
4478 struct perf_read_data data;
4481 * Orders the ->state and ->oncpu loads such that if we see
4482 * ACTIVE we must also see the right ->oncpu.
4484 * Matches the smp_wmb() from event_sched_in().
4488 event_cpu = READ_ONCE(event->oncpu);
4489 if ((unsigned)event_cpu >= nr_cpu_ids)
4492 data = (struct perf_read_data){
4499 event_cpu = __perf_event_read_cpu(event, event_cpu);
4502 * Purposely ignore the smp_call_function_single() return
4505 * If event_cpu isn't a valid CPU it means the event got
4506 * scheduled out and that will have updated the event count.
4508 * Therefore, either way, we'll have an up-to-date event count
4511 (void)smp_call_function_single(event_cpu, __perf_event_read, &data, 1);
4515 } else if (state == PERF_EVENT_STATE_INACTIVE) {
4516 struct perf_event_context *ctx = event->ctx;
4517 unsigned long flags;
4519 raw_spin_lock_irqsave(&ctx->lock, flags);
4520 state = event->state;
4521 if (state != PERF_EVENT_STATE_INACTIVE) {
4522 raw_spin_unlock_irqrestore(&ctx->lock, flags);
4527 * May read while context is not active (e.g., thread is
4528 * blocked), in that case we cannot update context time
4530 if (ctx->is_active & EVENT_TIME) {
4531 update_context_time(ctx);
4532 update_cgrp_time_from_event(event);
4535 perf_event_update_time(event);
4537 perf_event_update_sibling_time(event);
4538 raw_spin_unlock_irqrestore(&ctx->lock, flags);
4545 * Initialize the perf_event context in a task_struct:
4547 static void __perf_event_init_context(struct perf_event_context *ctx)
4549 raw_spin_lock_init(&ctx->lock);
4550 mutex_init(&ctx->mutex);
4551 INIT_LIST_HEAD(&ctx->active_ctx_list);
4552 perf_event_groups_init(&ctx->pinned_groups);
4553 perf_event_groups_init(&ctx->flexible_groups);
4554 INIT_LIST_HEAD(&ctx->event_list);
4555 INIT_LIST_HEAD(&ctx->pinned_active);
4556 INIT_LIST_HEAD(&ctx->flexible_active);
4557 refcount_set(&ctx->refcount, 1);
4560 static struct perf_event_context *
4561 alloc_perf_context(struct pmu *pmu, struct task_struct *task)
4563 struct perf_event_context *ctx;
4565 ctx = kzalloc(sizeof(struct perf_event_context), GFP_KERNEL);
4569 __perf_event_init_context(ctx);
4571 ctx->task = get_task_struct(task);
4577 static struct task_struct *
4578 find_lively_task_by_vpid(pid_t vpid)
4580 struct task_struct *task;
4586 task = find_task_by_vpid(vpid);
4588 get_task_struct(task);
4592 return ERR_PTR(-ESRCH);
4598 * Returns a matching context with refcount and pincount.
4600 static struct perf_event_context *
4601 find_get_context(struct pmu *pmu, struct task_struct *task,
4602 struct perf_event *event)
4604 struct perf_event_context *ctx, *clone_ctx = NULL;
4605 struct perf_cpu_context *cpuctx;
4606 void *task_ctx_data = NULL;
4607 unsigned long flags;
4609 int cpu = event->cpu;
4612 /* Must be root to operate on a CPU event: */
4613 err = perf_allow_cpu(&event->attr);
4615 return ERR_PTR(err);
4617 cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
4620 raw_spin_lock_irqsave(&ctx->lock, flags);
4622 raw_spin_unlock_irqrestore(&ctx->lock, flags);
4628 ctxn = pmu->task_ctx_nr;
4632 if (event->attach_state & PERF_ATTACH_TASK_DATA) {
4633 task_ctx_data = alloc_task_ctx_data(pmu);
4634 if (!task_ctx_data) {
4641 ctx = perf_lock_task_context(task, ctxn, &flags);
4643 clone_ctx = unclone_ctx(ctx);
4646 if (task_ctx_data && !ctx->task_ctx_data) {
4647 ctx->task_ctx_data = task_ctx_data;
4648 task_ctx_data = NULL;
4650 raw_spin_unlock_irqrestore(&ctx->lock, flags);
4655 ctx = alloc_perf_context(pmu, task);
4660 if (task_ctx_data) {
4661 ctx->task_ctx_data = task_ctx_data;
4662 task_ctx_data = NULL;
4666 mutex_lock(&task->perf_event_mutex);
4668 * If it has already passed perf_event_exit_task().
4669 * we must see PF_EXITING, it takes this mutex too.
4671 if (task->flags & PF_EXITING)
4673 else if (task->perf_event_ctxp[ctxn])
4678 rcu_assign_pointer(task->perf_event_ctxp[ctxn], ctx);
4680 mutex_unlock(&task->perf_event_mutex);
4682 if (unlikely(err)) {
4691 free_task_ctx_data(pmu, task_ctx_data);
4695 free_task_ctx_data(pmu, task_ctx_data);
4696 return ERR_PTR(err);
4699 static void perf_event_free_filter(struct perf_event *event);
4700 static void perf_event_free_bpf_prog(struct perf_event *event);
4702 static void free_event_rcu(struct rcu_head *head)
4704 struct perf_event *event;
4706 event = container_of(head, struct perf_event, rcu_head);
4708 put_pid_ns(event->ns);
4709 perf_event_free_filter(event);
4710 kmem_cache_free(perf_event_cache, event);
4713 static void ring_buffer_attach(struct perf_event *event,
4714 struct perf_buffer *rb);
4716 static void detach_sb_event(struct perf_event *event)
4718 struct pmu_event_list *pel = per_cpu_ptr(&pmu_sb_events, event->cpu);
4720 raw_spin_lock(&pel->lock);
4721 list_del_rcu(&event->sb_list);
4722 raw_spin_unlock(&pel->lock);
4725 static bool is_sb_event(struct perf_event *event)
4727 struct perf_event_attr *attr = &event->attr;
4732 if (event->attach_state & PERF_ATTACH_TASK)
4735 if (attr->mmap || attr->mmap_data || attr->mmap2 ||
4736 attr->comm || attr->comm_exec ||
4737 attr->task || attr->ksymbol ||
4738 attr->context_switch || attr->text_poke ||
4744 static void unaccount_pmu_sb_event(struct perf_event *event)
4746 if (is_sb_event(event))
4747 detach_sb_event(event);
4750 static void unaccount_event_cpu(struct perf_event *event, int cpu)
4755 if (is_cgroup_event(event))
4756 atomic_dec(&per_cpu(perf_cgroup_events, cpu));
4759 #ifdef CONFIG_NO_HZ_FULL
4760 static DEFINE_SPINLOCK(nr_freq_lock);
4763 static void unaccount_freq_event_nohz(void)
4765 #ifdef CONFIG_NO_HZ_FULL
4766 spin_lock(&nr_freq_lock);
4767 if (atomic_dec_and_test(&nr_freq_events))
4768 tick_nohz_dep_clear(TICK_DEP_BIT_PERF_EVENTS);
4769 spin_unlock(&nr_freq_lock);
4773 static void unaccount_freq_event(void)
4775 if (tick_nohz_full_enabled())
4776 unaccount_freq_event_nohz();
4778 atomic_dec(&nr_freq_events);
4781 static void unaccount_event(struct perf_event *event)
4788 if (event->attach_state & (PERF_ATTACH_TASK | PERF_ATTACH_SCHED_CB))
4790 if (event->attr.mmap || event->attr.mmap_data)
4791 atomic_dec(&nr_mmap_events);
4792 if (event->attr.build_id)
4793 atomic_dec(&nr_build_id_events);
4794 if (event->attr.comm)
4795 atomic_dec(&nr_comm_events);
4796 if (event->attr.namespaces)
4797 atomic_dec(&nr_namespaces_events);
4798 if (event->attr.cgroup)
4799 atomic_dec(&nr_cgroup_events);
4800 if (event->attr.task)
4801 atomic_dec(&nr_task_events);
4802 if (event->attr.freq)
4803 unaccount_freq_event();
4804 if (event->attr.context_switch) {
4806 atomic_dec(&nr_switch_events);
4808 if (is_cgroup_event(event))
4810 if (has_branch_stack(event))
4812 if (event->attr.ksymbol)
4813 atomic_dec(&nr_ksymbol_events);
4814 if (event->attr.bpf_event)
4815 atomic_dec(&nr_bpf_events);
4816 if (event->attr.text_poke)
4817 atomic_dec(&nr_text_poke_events);
4820 if (!atomic_add_unless(&perf_sched_count, -1, 1))
4821 schedule_delayed_work(&perf_sched_work, HZ);
4824 unaccount_event_cpu(event, event->cpu);
4826 unaccount_pmu_sb_event(event);
4829 static void perf_sched_delayed(struct work_struct *work)
4831 mutex_lock(&perf_sched_mutex);
4832 if (atomic_dec_and_test(&perf_sched_count))
4833 static_branch_disable(&perf_sched_events);
4834 mutex_unlock(&perf_sched_mutex);
4838 * The following implement mutual exclusion of events on "exclusive" pmus
4839 * (PERF_PMU_CAP_EXCLUSIVE). Such pmus can only have one event scheduled
4840 * at a time, so we disallow creating events that might conflict, namely:
4842 * 1) cpu-wide events in the presence of per-task events,
4843 * 2) per-task events in the presence of cpu-wide events,
4844 * 3) two matching events on the same context.
4846 * The former two cases are handled in the allocation path (perf_event_alloc(),
4847 * _free_event()), the latter -- before the first perf_install_in_context().
4849 static int exclusive_event_init(struct perf_event *event)
4851 struct pmu *pmu = event->pmu;
4853 if (!is_exclusive_pmu(pmu))
4857 * Prevent co-existence of per-task and cpu-wide events on the
4858 * same exclusive pmu.
4860 * Negative pmu::exclusive_cnt means there are cpu-wide
4861 * events on this "exclusive" pmu, positive means there are
4864 * Since this is called in perf_event_alloc() path, event::ctx
4865 * doesn't exist yet; it is, however, safe to use PERF_ATTACH_TASK
4866 * to mean "per-task event", because unlike other attach states it
4867 * never gets cleared.
4869 if (event->attach_state & PERF_ATTACH_TASK) {
4870 if (!atomic_inc_unless_negative(&pmu->exclusive_cnt))
4873 if (!atomic_dec_unless_positive(&pmu->exclusive_cnt))
4880 static void exclusive_event_destroy(struct perf_event *event)
4882 struct pmu *pmu = event->pmu;
4884 if (!is_exclusive_pmu(pmu))
4887 /* see comment in exclusive_event_init() */
4888 if (event->attach_state & PERF_ATTACH_TASK)
4889 atomic_dec(&pmu->exclusive_cnt);
4891 atomic_inc(&pmu->exclusive_cnt);
4894 static bool exclusive_event_match(struct perf_event *e1, struct perf_event *e2)
4896 if ((e1->pmu == e2->pmu) &&
4897 (e1->cpu == e2->cpu ||
4904 static bool exclusive_event_installable(struct perf_event *event,
4905 struct perf_event_context *ctx)
4907 struct perf_event *iter_event;
4908 struct pmu *pmu = event->pmu;
4910 lockdep_assert_held(&ctx->mutex);
4912 if (!is_exclusive_pmu(pmu))
4915 list_for_each_entry(iter_event, &ctx->event_list, event_entry) {
4916 if (exclusive_event_match(iter_event, event))
4923 static void perf_addr_filters_splice(struct perf_event *event,
4924 struct list_head *head);
4926 static void _free_event(struct perf_event *event)
4928 irq_work_sync(&event->pending);
4930 unaccount_event(event);
4932 security_perf_event_free(event);
4936 * Can happen when we close an event with re-directed output.
4938 * Since we have a 0 refcount, perf_mmap_close() will skip
4939 * over us; possibly making our ring_buffer_put() the last.
4941 mutex_lock(&event->mmap_mutex);
4942 ring_buffer_attach(event, NULL);
4943 mutex_unlock(&event->mmap_mutex);
4946 if (is_cgroup_event(event))
4947 perf_detach_cgroup(event);
4949 if (!event->parent) {
4950 if (event->attr.sample_type & PERF_SAMPLE_CALLCHAIN)
4951 put_callchain_buffers();
4954 perf_event_free_bpf_prog(event);
4955 perf_addr_filters_splice(event, NULL);
4956 kfree(event->addr_filter_ranges);
4959 event->destroy(event);
4962 * Must be after ->destroy(), due to uprobe_perf_close() using
4965 if (event->hw.target)
4966 put_task_struct(event->hw.target);
4969 * perf_event_free_task() relies on put_ctx() being 'last', in particular
4970 * all task references must be cleaned up.
4973 put_ctx(event->ctx);
4975 exclusive_event_destroy(event);
4976 module_put(event->pmu->module);
4978 call_rcu(&event->rcu_head, free_event_rcu);
4982 * Used to free events which have a known refcount of 1, such as in error paths
4983 * where the event isn't exposed yet and inherited events.
4985 static void free_event(struct perf_event *event)
4987 if (WARN(atomic_long_cmpxchg(&event->refcount, 1, 0) != 1,
4988 "unexpected event refcount: %ld; ptr=%p\n",
4989 atomic_long_read(&event->refcount), event)) {
4990 /* leak to avoid use-after-free */
4998 * Remove user event from the owner task.
5000 static void perf_remove_from_owner(struct perf_event *event)
5002 struct task_struct *owner;
5006 * Matches the smp_store_release() in perf_event_exit_task(). If we
5007 * observe !owner it means the list deletion is complete and we can
5008 * indeed free this event, otherwise we need to serialize on
5009 * owner->perf_event_mutex.
5011 owner = READ_ONCE(event->owner);
5014 * Since delayed_put_task_struct() also drops the last
5015 * task reference we can safely take a new reference
5016 * while holding the rcu_read_lock().
5018 get_task_struct(owner);
5024 * If we're here through perf_event_exit_task() we're already
5025 * holding ctx->mutex which would be an inversion wrt. the
5026 * normal lock order.
5028 * However we can safely take this lock because its the child
5031 mutex_lock_nested(&owner->perf_event_mutex, SINGLE_DEPTH_NESTING);
5034 * We have to re-check the event->owner field, if it is cleared
5035 * we raced with perf_event_exit_task(), acquiring the mutex
5036 * ensured they're done, and we can proceed with freeing the
5040 list_del_init(&event->owner_entry);
5041 smp_store_release(&event->owner, NULL);
5043 mutex_unlock(&owner->perf_event_mutex);
5044 put_task_struct(owner);
5048 static void put_event(struct perf_event *event)
5050 if (!atomic_long_dec_and_test(&event->refcount))
5057 * Kill an event dead; while event:refcount will preserve the event
5058 * object, it will not preserve its functionality. Once the last 'user'
5059 * gives up the object, we'll destroy the thing.
5061 int perf_event_release_kernel(struct perf_event *event)
5063 struct perf_event_context *ctx = event->ctx;
5064 struct perf_event *child, *tmp;
5065 LIST_HEAD(free_list);
5068 * If we got here through err_file: fput(event_file); we will not have
5069 * attached to a context yet.
5072 WARN_ON_ONCE(event->attach_state &
5073 (PERF_ATTACH_CONTEXT|PERF_ATTACH_GROUP));
5077 if (!is_kernel_event(event))
5078 perf_remove_from_owner(event);
5080 ctx = perf_event_ctx_lock(event);
5081 WARN_ON_ONCE(ctx->parent_ctx);
5082 perf_remove_from_context(event, DETACH_GROUP);
5084 raw_spin_lock_irq(&ctx->lock);
5086 * Mark this event as STATE_DEAD, there is no external reference to it
5089 * Anybody acquiring event->child_mutex after the below loop _must_
5090 * also see this, most importantly inherit_event() which will avoid
5091 * placing more children on the list.
5093 * Thus this guarantees that we will in fact observe and kill _ALL_
5096 event->state = PERF_EVENT_STATE_DEAD;
5097 raw_spin_unlock_irq(&ctx->lock);
5099 perf_event_ctx_unlock(event, ctx);
5102 mutex_lock(&event->child_mutex);
5103 list_for_each_entry(child, &event->child_list, child_list) {
5106 * Cannot change, child events are not migrated, see the
5107 * comment with perf_event_ctx_lock_nested().
5109 ctx = READ_ONCE(child->ctx);
5111 * Since child_mutex nests inside ctx::mutex, we must jump
5112 * through hoops. We start by grabbing a reference on the ctx.
5114 * Since the event cannot get freed while we hold the
5115 * child_mutex, the context must also exist and have a !0
5121 * Now that we have a ctx ref, we can drop child_mutex, and
5122 * acquire ctx::mutex without fear of it going away. Then we
5123 * can re-acquire child_mutex.
5125 mutex_unlock(&event->child_mutex);
5126 mutex_lock(&ctx->mutex);
5127 mutex_lock(&event->child_mutex);
5130 * Now that we hold ctx::mutex and child_mutex, revalidate our
5131 * state, if child is still the first entry, it didn't get freed
5132 * and we can continue doing so.
5134 tmp = list_first_entry_or_null(&event->child_list,
5135 struct perf_event, child_list);
5137 perf_remove_from_context(child, DETACH_GROUP);
5138 list_move(&child->child_list, &free_list);
5140 * This matches the refcount bump in inherit_event();
5141 * this can't be the last reference.
5146 mutex_unlock(&event->child_mutex);
5147 mutex_unlock(&ctx->mutex);
5151 mutex_unlock(&event->child_mutex);
5153 list_for_each_entry_safe(child, tmp, &free_list, child_list) {
5154 void *var = &child->ctx->refcount;
5156 list_del(&child->child_list);
5160 * Wake any perf_event_free_task() waiting for this event to be
5163 smp_mb(); /* pairs with wait_var_event() */
5168 put_event(event); /* Must be the 'last' reference */
5171 EXPORT_SYMBOL_GPL(perf_event_release_kernel);
5174 * Called when the last reference to the file is gone.
5176 static int perf_release(struct inode *inode, struct file *file)
5178 perf_event_release_kernel(file->private_data);
5182 static u64 __perf_event_read_value(struct perf_event *event, u64 *enabled, u64 *running)
5184 struct perf_event *child;
5190 mutex_lock(&event->child_mutex);
5192 (void)perf_event_read(event, false);
5193 total += perf_event_count(event);
5195 *enabled += event->total_time_enabled +
5196 atomic64_read(&event->child_total_time_enabled);
5197 *running += event->total_time_running +
5198 atomic64_read(&event->child_total_time_running);
5200 list_for_each_entry(child, &event->child_list, child_list) {
5201 (void)perf_event_read(child, false);
5202 total += perf_event_count(child);
5203 *enabled += child->total_time_enabled;
5204 *running += child->total_time_running;
5206 mutex_unlock(&event->child_mutex);
5211 u64 perf_event_read_value(struct perf_event *event, u64 *enabled, u64 *running)
5213 struct perf_event_context *ctx;
5216 ctx = perf_event_ctx_lock(event);
5217 count = __perf_event_read_value(event, enabled, running);
5218 perf_event_ctx_unlock(event, ctx);
5222 EXPORT_SYMBOL_GPL(perf_event_read_value);
5224 static int __perf_read_group_add(struct perf_event *leader,
5225 u64 read_format, u64 *values)
5227 struct perf_event_context *ctx = leader->ctx;
5228 struct perf_event *sub;
5229 unsigned long flags;
5230 int n = 1; /* skip @nr */
5233 ret = perf_event_read(leader, true);
5237 raw_spin_lock_irqsave(&ctx->lock, flags);
5240 * Since we co-schedule groups, {enabled,running} times of siblings
5241 * will be identical to those of the leader, so we only publish one
5244 if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED) {
5245 values[n++] += leader->total_time_enabled +
5246 atomic64_read(&leader->child_total_time_enabled);
5249 if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING) {
5250 values[n++] += leader->total_time_running +
5251 atomic64_read(&leader->child_total_time_running);
5255 * Write {count,id} tuples for every sibling.
5257 values[n++] += perf_event_count(leader);
5258 if (read_format & PERF_FORMAT_ID)
5259 values[n++] = primary_event_id(leader);
5261 for_each_sibling_event(sub, leader) {
5262 values[n++] += perf_event_count(sub);
5263 if (read_format & PERF_FORMAT_ID)
5264 values[n++] = primary_event_id(sub);
5267 raw_spin_unlock_irqrestore(&ctx->lock, flags);
5271 static int perf_read_group(struct perf_event *event,
5272 u64 read_format, char __user *buf)
5274 struct perf_event *leader = event->group_leader, *child;
5275 struct perf_event_context *ctx = leader->ctx;
5279 lockdep_assert_held(&ctx->mutex);
5281 values = kzalloc(event->read_size, GFP_KERNEL);
5285 values[0] = 1 + leader->nr_siblings;
5288 * By locking the child_mutex of the leader we effectively
5289 * lock the child list of all siblings.. XXX explain how.
5291 mutex_lock(&leader->child_mutex);
5293 ret = __perf_read_group_add(leader, read_format, values);
5297 list_for_each_entry(child, &leader->child_list, child_list) {
5298 ret = __perf_read_group_add(child, read_format, values);
5303 mutex_unlock(&leader->child_mutex);
5305 ret = event->read_size;
5306 if (copy_to_user(buf, values, event->read_size))
5311 mutex_unlock(&leader->child_mutex);
5317 static int perf_read_one(struct perf_event *event,
5318 u64 read_format, char __user *buf)
5320 u64 enabled, running;
5324 values[n++] = __perf_event_read_value(event, &enabled, &running);
5325 if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED)
5326 values[n++] = enabled;
5327 if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING)
5328 values[n++] = running;
5329 if (read_format & PERF_FORMAT_ID)
5330 values[n++] = primary_event_id(event);
5332 if (copy_to_user(buf, values, n * sizeof(u64)))
5335 return n * sizeof(u64);
5338 static bool is_event_hup(struct perf_event *event)
5342 if (event->state > PERF_EVENT_STATE_EXIT)
5345 mutex_lock(&event->child_mutex);
5346 no_children = list_empty(&event->child_list);
5347 mutex_unlock(&event->child_mutex);
5352 * Read the performance event - simple non blocking version for now
5355 __perf_read(struct perf_event *event, char __user *buf, size_t count)
5357 u64 read_format = event->attr.read_format;
5361 * Return end-of-file for a read on an event that is in
5362 * error state (i.e. because it was pinned but it couldn't be
5363 * scheduled on to the CPU at some point).
5365 if (event->state == PERF_EVENT_STATE_ERROR)
5368 if (count < event->read_size)
5371 WARN_ON_ONCE(event->ctx->parent_ctx);
5372 if (read_format & PERF_FORMAT_GROUP)
5373 ret = perf_read_group(event, read_format, buf);
5375 ret = perf_read_one(event, read_format, buf);
5381 perf_read(struct file *file, char __user *buf, size_t count, loff_t *ppos)
5383 struct perf_event *event = file->private_data;
5384 struct perf_event_context *ctx;
5387 ret = security_perf_event_read(event);
5391 ctx = perf_event_ctx_lock(event);
5392 ret = __perf_read(event, buf, count);
5393 perf_event_ctx_unlock(event, ctx);
5398 static __poll_t perf_poll(struct file *file, poll_table *wait)
5400 struct perf_event *event = file->private_data;
5401 struct perf_buffer *rb;
5402 __poll_t events = EPOLLHUP;
5404 poll_wait(file, &event->waitq, wait);
5406 if (is_event_hup(event))
5410 * Pin the event->rb by taking event->mmap_mutex; otherwise
5411 * perf_event_set_output() can swizzle our rb and make us miss wakeups.
5413 mutex_lock(&event->mmap_mutex);
5416 events = atomic_xchg(&rb->poll, 0);
5417 mutex_unlock(&event->mmap_mutex);
5421 static void _perf_event_reset(struct perf_event *event)
5423 (void)perf_event_read(event, false);
5424 local64_set(&event->count, 0);
5425 perf_event_update_userpage(event);
5428 /* Assume it's not an event with inherit set. */
5429 u64 perf_event_pause(struct perf_event *event, bool reset)
5431 struct perf_event_context *ctx;
5434 ctx = perf_event_ctx_lock(event);
5435 WARN_ON_ONCE(event->attr.inherit);
5436 _perf_event_disable(event);
5437 count = local64_read(&event->count);
5439 local64_set(&event->count, 0);
5440 perf_event_ctx_unlock(event, ctx);
5444 EXPORT_SYMBOL_GPL(perf_event_pause);
5447 * Holding the top-level event's child_mutex means that any
5448 * descendant process that has inherited this event will block
5449 * in perf_event_exit_event() if it goes to exit, thus satisfying the
5450 * task existence requirements of perf_event_enable/disable.
5452 static void perf_event_for_each_child(struct perf_event *event,
5453 void (*func)(struct perf_event *))
5455 struct perf_event *child;
5457 WARN_ON_ONCE(event->ctx->parent_ctx);
5459 mutex_lock(&event->child_mutex);
5461 list_for_each_entry(child, &event->child_list, child_list)
5463 mutex_unlock(&event->child_mutex);
5466 static void perf_event_for_each(struct perf_event *event,
5467 void (*func)(struct perf_event *))
5469 struct perf_event_context *ctx = event->ctx;
5470 struct perf_event *sibling;
5472 lockdep_assert_held(&ctx->mutex);
5474 event = event->group_leader;
5476 perf_event_for_each_child(event, func);
5477 for_each_sibling_event(sibling, event)
5478 perf_event_for_each_child(sibling, func);
5481 static void __perf_event_period(struct perf_event *event,
5482 struct perf_cpu_context *cpuctx,
5483 struct perf_event_context *ctx,
5486 u64 value = *((u64 *)info);
5489 if (event->attr.freq) {
5490 event->attr.sample_freq = value;
5492 event->attr.sample_period = value;
5493 event->hw.sample_period = value;
5496 active = (event->state == PERF_EVENT_STATE_ACTIVE);
5498 perf_pmu_disable(ctx->pmu);
5500 * We could be throttled; unthrottle now to avoid the tick
5501 * trying to unthrottle while we already re-started the event.
5503 if (event->hw.interrupts == MAX_INTERRUPTS) {
5504 event->hw.interrupts = 0;
5505 perf_log_throttle(event, 1);
5507 event->pmu->stop(event, PERF_EF_UPDATE);
5510 local64_set(&event->hw.period_left, 0);
5513 event->pmu->start(event, PERF_EF_RELOAD);
5514 perf_pmu_enable(ctx->pmu);
5518 static int perf_event_check_period(struct perf_event *event, u64 value)
5520 return event->pmu->check_period(event, value);
5523 static int _perf_event_period(struct perf_event *event, u64 value)
5525 if (!is_sampling_event(event))
5531 if (event->attr.freq && value > sysctl_perf_event_sample_rate)
5534 if (perf_event_check_period(event, value))
5537 if (!event->attr.freq && (value & (1ULL << 63)))
5540 event_function_call(event, __perf_event_period, &value);
5545 int perf_event_period(struct perf_event *event, u64 value)
5547 struct perf_event_context *ctx;
5550 ctx = perf_event_ctx_lock(event);
5551 ret = _perf_event_period(event, value);
5552 perf_event_ctx_unlock(event, ctx);
5556 EXPORT_SYMBOL_GPL(perf_event_period);
5558 static const struct file_operations perf_fops;
5560 static inline int perf_fget_light(int fd, struct fd *p)
5562 struct fd f = fdget(fd);
5566 if (f.file->f_op != &perf_fops) {
5574 static int perf_event_set_output(struct perf_event *event,
5575 struct perf_event *output_event);
5576 static int perf_event_set_filter(struct perf_event *event, void __user *arg);
5577 static int perf_event_set_bpf_prog(struct perf_event *event, u32 prog_fd);
5578 static int perf_copy_attr(struct perf_event_attr __user *uattr,
5579 struct perf_event_attr *attr);
5581 static long _perf_ioctl(struct perf_event *event, unsigned int cmd, unsigned long arg)
5583 void (*func)(struct perf_event *);
5587 case PERF_EVENT_IOC_ENABLE:
5588 func = _perf_event_enable;
5590 case PERF_EVENT_IOC_DISABLE:
5591 func = _perf_event_disable;
5593 case PERF_EVENT_IOC_RESET:
5594 func = _perf_event_reset;
5597 case PERF_EVENT_IOC_REFRESH:
5598 return _perf_event_refresh(event, arg);
5600 case PERF_EVENT_IOC_PERIOD:
5604 if (copy_from_user(&value, (u64 __user *)arg, sizeof(value)))
5607 return _perf_event_period(event, value);
5609 case PERF_EVENT_IOC_ID:
5611 u64 id = primary_event_id(event);
5613 if (copy_to_user((void __user *)arg, &id, sizeof(id)))
5618 case PERF_EVENT_IOC_SET_OUTPUT:
5622 struct perf_event *output_event;
5624 ret = perf_fget_light(arg, &output);
5627 output_event = output.file->private_data;
5628 ret = perf_event_set_output(event, output_event);
5631 ret = perf_event_set_output(event, NULL);
5636 case PERF_EVENT_IOC_SET_FILTER:
5637 return perf_event_set_filter(event, (void __user *)arg);
5639 case PERF_EVENT_IOC_SET_BPF:
5640 return perf_event_set_bpf_prog(event, arg);
5642 case PERF_EVENT_IOC_PAUSE_OUTPUT: {
5643 struct perf_buffer *rb;
5646 rb = rcu_dereference(event->rb);
5647 if (!rb || !rb->nr_pages) {
5651 rb_toggle_paused(rb, !!arg);
5656 case PERF_EVENT_IOC_QUERY_BPF:
5657 return perf_event_query_prog_array(event, (void __user *)arg);
5659 case PERF_EVENT_IOC_MODIFY_ATTRIBUTES: {
5660 struct perf_event_attr new_attr;
5661 int err = perf_copy_attr((struct perf_event_attr __user *)arg,
5667 return perf_event_modify_attr(event, &new_attr);
5673 if (flags & PERF_IOC_FLAG_GROUP)
5674 perf_event_for_each(event, func);
5676 perf_event_for_each_child(event, func);
5681 static long perf_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
5683 struct perf_event *event = file->private_data;
5684 struct perf_event_context *ctx;
5687 /* Treat ioctl like writes as it is likely a mutating operation. */
5688 ret = security_perf_event_write(event);
5692 ctx = perf_event_ctx_lock(event);
5693 ret = _perf_ioctl(event, cmd, arg);
5694 perf_event_ctx_unlock(event, ctx);
5699 #ifdef CONFIG_COMPAT
5700 static long perf_compat_ioctl(struct file *file, unsigned int cmd,
5703 switch (_IOC_NR(cmd)) {
5704 case _IOC_NR(PERF_EVENT_IOC_SET_FILTER):
5705 case _IOC_NR(PERF_EVENT_IOC_ID):
5706 case _IOC_NR(PERF_EVENT_IOC_QUERY_BPF):
5707 case _IOC_NR(PERF_EVENT_IOC_MODIFY_ATTRIBUTES):
5708 /* Fix up pointer size (usually 4 -> 8 in 32-on-64-bit case */
5709 if (_IOC_SIZE(cmd) == sizeof(compat_uptr_t)) {
5710 cmd &= ~IOCSIZE_MASK;
5711 cmd |= sizeof(void *) << IOCSIZE_SHIFT;
5715 return perf_ioctl(file, cmd, arg);
5718 # define perf_compat_ioctl NULL
5721 int perf_event_task_enable(void)
5723 struct perf_event_context *ctx;
5724 struct perf_event *event;
5726 mutex_lock(¤t->perf_event_mutex);
5727 list_for_each_entry(event, ¤t->perf_event_list, owner_entry) {
5728 ctx = perf_event_ctx_lock(event);
5729 perf_event_for_each_child(event, _perf_event_enable);
5730 perf_event_ctx_unlock(event, ctx);
5732 mutex_unlock(¤t->perf_event_mutex);
5737 int perf_event_task_disable(void)
5739 struct perf_event_context *ctx;
5740 struct perf_event *event;
5742 mutex_lock(¤t->perf_event_mutex);
5743 list_for_each_entry(event, ¤t->perf_event_list, owner_entry) {
5744 ctx = perf_event_ctx_lock(event);
5745 perf_event_for_each_child(event, _perf_event_disable);
5746 perf_event_ctx_unlock(event, ctx);
5748 mutex_unlock(¤t->perf_event_mutex);
5753 static int perf_event_index(struct perf_event *event)
5755 if (event->hw.state & PERF_HES_STOPPED)
5758 if (event->state != PERF_EVENT_STATE_ACTIVE)
5761 return event->pmu->event_idx(event);
5764 static void calc_timer_values(struct perf_event *event,
5771 *now = perf_clock();
5772 ctx_time = event->shadow_ctx_time + *now;
5773 __perf_update_times(event, ctx_time, enabled, running);
5776 static void perf_event_init_userpage(struct perf_event *event)
5778 struct perf_event_mmap_page *userpg;
5779 struct perf_buffer *rb;
5782 rb = rcu_dereference(event->rb);
5786 userpg = rb->user_page;
5788 /* Allow new userspace to detect that bit 0 is deprecated */
5789 userpg->cap_bit0_is_deprecated = 1;
5790 userpg->size = offsetof(struct perf_event_mmap_page, __reserved);
5791 userpg->data_offset = PAGE_SIZE;
5792 userpg->data_size = perf_data_size(rb);
5798 void __weak arch_perf_update_userpage(
5799 struct perf_event *event, struct perf_event_mmap_page *userpg, u64 now)
5804 * Callers need to ensure there can be no nesting of this function, otherwise
5805 * the seqlock logic goes bad. We can not serialize this because the arch
5806 * code calls this from NMI context.
5808 void perf_event_update_userpage(struct perf_event *event)
5810 struct perf_event_mmap_page *userpg;
5811 struct perf_buffer *rb;
5812 u64 enabled, running, now;
5815 rb = rcu_dereference(event->rb);
5820 * compute total_time_enabled, total_time_running
5821 * based on snapshot values taken when the event
5822 * was last scheduled in.
5824 * we cannot simply called update_context_time()
5825 * because of locking issue as we can be called in
5828 calc_timer_values(event, &now, &enabled, &running);
5830 userpg = rb->user_page;
5832 * Disable preemption to guarantee consistent time stamps are stored to
5838 userpg->index = perf_event_index(event);
5839 userpg->offset = perf_event_count(event);
5841 userpg->offset -= local64_read(&event->hw.prev_count);
5843 userpg->time_enabled = enabled +
5844 atomic64_read(&event->child_total_time_enabled);
5846 userpg->time_running = running +
5847 atomic64_read(&event->child_total_time_running);
5849 arch_perf_update_userpage(event, userpg, now);
5857 EXPORT_SYMBOL_GPL(perf_event_update_userpage);
5859 static vm_fault_t perf_mmap_fault(struct vm_fault *vmf)
5861 struct perf_event *event = vmf->vma->vm_file->private_data;
5862 struct perf_buffer *rb;
5863 vm_fault_t ret = VM_FAULT_SIGBUS;
5865 if (vmf->flags & FAULT_FLAG_MKWRITE) {
5866 if (vmf->pgoff == 0)
5872 rb = rcu_dereference(event->rb);
5876 if (vmf->pgoff && (vmf->flags & FAULT_FLAG_WRITE))
5879 vmf->page = perf_mmap_to_page(rb, vmf->pgoff);
5883 get_page(vmf->page);
5884 vmf->page->mapping = vmf->vma->vm_file->f_mapping;
5885 vmf->page->index = vmf->pgoff;
5894 static void ring_buffer_attach(struct perf_event *event,
5895 struct perf_buffer *rb)
5897 struct perf_buffer *old_rb = NULL;
5898 unsigned long flags;
5902 * Should be impossible, we set this when removing
5903 * event->rb_entry and wait/clear when adding event->rb_entry.
5905 WARN_ON_ONCE(event->rcu_pending);
5908 spin_lock_irqsave(&old_rb->event_lock, flags);
5909 list_del_rcu(&event->rb_entry);
5910 spin_unlock_irqrestore(&old_rb->event_lock, flags);
5912 event->rcu_batches = get_state_synchronize_rcu();
5913 event->rcu_pending = 1;
5917 if (event->rcu_pending) {
5918 cond_synchronize_rcu(event->rcu_batches);
5919 event->rcu_pending = 0;
5922 spin_lock_irqsave(&rb->event_lock, flags);
5923 list_add_rcu(&event->rb_entry, &rb->event_list);
5924 spin_unlock_irqrestore(&rb->event_lock, flags);
5928 * Avoid racing with perf_mmap_close(AUX): stop the event
5929 * before swizzling the event::rb pointer; if it's getting
5930 * unmapped, its aux_mmap_count will be 0 and it won't
5931 * restart. See the comment in __perf_pmu_output_stop().
5933 * Data will inevitably be lost when set_output is done in
5934 * mid-air, but then again, whoever does it like this is
5935 * not in for the data anyway.
5938 perf_event_stop(event, 0);
5940 rcu_assign_pointer(event->rb, rb);
5943 ring_buffer_put(old_rb);
5945 * Since we detached before setting the new rb, so that we
5946 * could attach the new rb, we could have missed a wakeup.
5949 wake_up_all(&event->waitq);
5953 static void ring_buffer_wakeup(struct perf_event *event)
5955 struct perf_buffer *rb;
5958 rb = rcu_dereference(event->rb);
5960 list_for_each_entry_rcu(event, &rb->event_list, rb_entry)
5961 wake_up_all(&event->waitq);
5966 struct perf_buffer *ring_buffer_get(struct perf_event *event)
5968 struct perf_buffer *rb;
5971 rb = rcu_dereference(event->rb);
5973 if (!refcount_inc_not_zero(&rb->refcount))
5981 void ring_buffer_put(struct perf_buffer *rb)
5983 if (!refcount_dec_and_test(&rb->refcount))
5986 WARN_ON_ONCE(!list_empty(&rb->event_list));
5988 call_rcu(&rb->rcu_head, rb_free_rcu);
5991 static void perf_mmap_open(struct vm_area_struct *vma)
5993 struct perf_event *event = vma->vm_file->private_data;
5995 atomic_inc(&event->mmap_count);
5996 atomic_inc(&event->rb->mmap_count);
5999 atomic_inc(&event->rb->aux_mmap_count);
6001 if (event->pmu->event_mapped)
6002 event->pmu->event_mapped(event, vma->vm_mm);
6005 static void perf_pmu_output_stop(struct perf_event *event);
6008 * A buffer can be mmap()ed multiple times; either directly through the same
6009 * event, or through other events by use of perf_event_set_output().
6011 * In order to undo the VM accounting done by perf_mmap() we need to destroy
6012 * the buffer here, where we still have a VM context. This means we need
6013 * to detach all events redirecting to us.
6015 static void perf_mmap_close(struct vm_area_struct *vma)
6017 struct perf_event *event = vma->vm_file->private_data;
6018 struct perf_buffer *rb = ring_buffer_get(event);
6019 struct user_struct *mmap_user = rb->mmap_user;
6020 int mmap_locked = rb->mmap_locked;
6021 unsigned long size = perf_data_size(rb);
6022 bool detach_rest = false;
6024 if (event->pmu->event_unmapped)
6025 event->pmu->event_unmapped(event, vma->vm_mm);
6028 * rb->aux_mmap_count will always drop before rb->mmap_count and
6029 * event->mmap_count, so it is ok to use event->mmap_mutex to
6030 * serialize with perf_mmap here.
6032 if (rb_has_aux(rb) && vma->vm_pgoff == rb->aux_pgoff &&
6033 atomic_dec_and_mutex_lock(&rb->aux_mmap_count, &event->mmap_mutex)) {
6035 * Stop all AUX events that are writing to this buffer,
6036 * so that we can free its AUX pages and corresponding PMU
6037 * data. Note that after rb::aux_mmap_count dropped to zero,
6038 * they won't start any more (see perf_aux_output_begin()).
6040 perf_pmu_output_stop(event);
6042 /* now it's safe to free the pages */
6043 atomic_long_sub(rb->aux_nr_pages - rb->aux_mmap_locked, &mmap_user->locked_vm);
6044 atomic64_sub(rb->aux_mmap_locked, &vma->vm_mm->pinned_vm);
6046 /* this has to be the last one */
6048 WARN_ON_ONCE(refcount_read(&rb->aux_refcount));
6050 mutex_unlock(&event->mmap_mutex);
6053 if (atomic_dec_and_test(&rb->mmap_count))
6056 if (!atomic_dec_and_mutex_lock(&event->mmap_count, &event->mmap_mutex))
6059 ring_buffer_attach(event, NULL);
6060 mutex_unlock(&event->mmap_mutex);
6062 /* If there's still other mmap()s of this buffer, we're done. */
6067 * No other mmap()s, detach from all other events that might redirect
6068 * into the now unreachable buffer. Somewhat complicated by the
6069 * fact that rb::event_lock otherwise nests inside mmap_mutex.
6073 list_for_each_entry_rcu(event, &rb->event_list, rb_entry) {
6074 if (!atomic_long_inc_not_zero(&event->refcount)) {
6076 * This event is en-route to free_event() which will
6077 * detach it and remove it from the list.
6083 mutex_lock(&event->mmap_mutex);
6085 * Check we didn't race with perf_event_set_output() which can
6086 * swizzle the rb from under us while we were waiting to
6087 * acquire mmap_mutex.
6089 * If we find a different rb; ignore this event, a next
6090 * iteration will no longer find it on the list. We have to
6091 * still restart the iteration to make sure we're not now
6092 * iterating the wrong list.
6094 if (event->rb == rb)
6095 ring_buffer_attach(event, NULL);
6097 mutex_unlock(&event->mmap_mutex);
6101 * Restart the iteration; either we're on the wrong list or
6102 * destroyed its integrity by doing a deletion.
6109 * It could be there's still a few 0-ref events on the list; they'll
6110 * get cleaned up by free_event() -- they'll also still have their
6111 * ref on the rb and will free it whenever they are done with it.
6113 * Aside from that, this buffer is 'fully' detached and unmapped,
6114 * undo the VM accounting.
6117 atomic_long_sub((size >> PAGE_SHIFT) + 1 - mmap_locked,
6118 &mmap_user->locked_vm);
6119 atomic64_sub(mmap_locked, &vma->vm_mm->pinned_vm);
6120 free_uid(mmap_user);
6123 ring_buffer_put(rb); /* could be last */
6126 static const struct vm_operations_struct perf_mmap_vmops = {
6127 .open = perf_mmap_open,
6128 .close = perf_mmap_close, /* non mergeable */
6129 .fault = perf_mmap_fault,
6130 .page_mkwrite = perf_mmap_fault,
6133 static int perf_mmap(struct file *file, struct vm_area_struct *vma)
6135 struct perf_event *event = file->private_data;
6136 unsigned long user_locked, user_lock_limit;
6137 struct user_struct *user = current_user();
6138 struct perf_buffer *rb = NULL;
6139 unsigned long locked, lock_limit;
6140 unsigned long vma_size;
6141 unsigned long nr_pages;
6142 long user_extra = 0, extra = 0;
6143 int ret = 0, flags = 0;
6146 * Don't allow mmap() of inherited per-task counters. This would
6147 * create a performance issue due to all children writing to the
6150 if (event->cpu == -1 && event->attr.inherit)
6153 if (!(vma->vm_flags & VM_SHARED))
6156 ret = security_perf_event_read(event);
6160 vma_size = vma->vm_end - vma->vm_start;
6162 if (vma->vm_pgoff == 0) {
6163 nr_pages = (vma_size / PAGE_SIZE) - 1;
6166 * AUX area mapping: if rb->aux_nr_pages != 0, it's already
6167 * mapped, all subsequent mappings should have the same size
6168 * and offset. Must be above the normal perf buffer.
6170 u64 aux_offset, aux_size;
6175 nr_pages = vma_size / PAGE_SIZE;
6177 mutex_lock(&event->mmap_mutex);
6184 aux_offset = READ_ONCE(rb->user_page->aux_offset);
6185 aux_size = READ_ONCE(rb->user_page->aux_size);
6187 if (aux_offset < perf_data_size(rb) + PAGE_SIZE)
6190 if (aux_offset != vma->vm_pgoff << PAGE_SHIFT)
6193 /* already mapped with a different offset */
6194 if (rb_has_aux(rb) && rb->aux_pgoff != vma->vm_pgoff)
6197 if (aux_size != vma_size || aux_size != nr_pages * PAGE_SIZE)
6200 /* already mapped with a different size */
6201 if (rb_has_aux(rb) && rb->aux_nr_pages != nr_pages)
6204 if (!is_power_of_2(nr_pages))
6207 if (!atomic_inc_not_zero(&rb->mmap_count))
6210 if (rb_has_aux(rb)) {
6211 atomic_inc(&rb->aux_mmap_count);
6216 atomic_set(&rb->aux_mmap_count, 1);
6217 user_extra = nr_pages;
6223 * If we have rb pages ensure they're a power-of-two number, so we
6224 * can do bitmasks instead of modulo.
6226 if (nr_pages != 0 && !is_power_of_2(nr_pages))
6229 if (vma_size != PAGE_SIZE * (1 + nr_pages))
6232 WARN_ON_ONCE(event->ctx->parent_ctx);
6234 mutex_lock(&event->mmap_mutex);
6236 if (event->rb->nr_pages != nr_pages) {
6241 if (!atomic_inc_not_zero(&event->rb->mmap_count)) {
6243 * Raced against perf_mmap_close() through
6244 * perf_event_set_output(). Try again, hope for better
6247 mutex_unlock(&event->mmap_mutex);
6254 user_extra = nr_pages + 1;
6257 user_lock_limit = sysctl_perf_event_mlock >> (PAGE_SHIFT - 10);
6260 * Increase the limit linearly with more CPUs:
6262 user_lock_limit *= num_online_cpus();
6264 user_locked = atomic_long_read(&user->locked_vm);
6267 * sysctl_perf_event_mlock may have changed, so that
6268 * user->locked_vm > user_lock_limit
6270 if (user_locked > user_lock_limit)
6271 user_locked = user_lock_limit;
6272 user_locked += user_extra;
6274 if (user_locked > user_lock_limit) {
6276 * charge locked_vm until it hits user_lock_limit;
6277 * charge the rest from pinned_vm
6279 extra = user_locked - user_lock_limit;
6280 user_extra -= extra;
6283 lock_limit = rlimit(RLIMIT_MEMLOCK);
6284 lock_limit >>= PAGE_SHIFT;
6285 locked = atomic64_read(&vma->vm_mm->pinned_vm) + extra;
6287 if ((locked > lock_limit) && perf_is_paranoid() &&
6288 !capable(CAP_IPC_LOCK)) {
6293 WARN_ON(!rb && event->rb);
6295 if (vma->vm_flags & VM_WRITE)
6296 flags |= RING_BUFFER_WRITABLE;
6299 rb = rb_alloc(nr_pages,
6300 event->attr.watermark ? event->attr.wakeup_watermark : 0,
6308 atomic_set(&rb->mmap_count, 1);
6309 rb->mmap_user = get_current_user();
6310 rb->mmap_locked = extra;
6312 ring_buffer_attach(event, rb);
6314 perf_event_init_userpage(event);
6315 perf_event_update_userpage(event);
6317 ret = rb_alloc_aux(rb, event, vma->vm_pgoff, nr_pages,
6318 event->attr.aux_watermark, flags);
6320 rb->aux_mmap_locked = extra;
6325 atomic_long_add(user_extra, &user->locked_vm);
6326 atomic64_add(extra, &vma->vm_mm->pinned_vm);
6328 atomic_inc(&event->mmap_count);
6330 atomic_dec(&rb->mmap_count);
6333 mutex_unlock(&event->mmap_mutex);
6336 * Since pinned accounting is per vm we cannot allow fork() to copy our
6339 vma->vm_flags |= VM_DONTCOPY | VM_DONTEXPAND | VM_DONTDUMP;
6340 vma->vm_ops = &perf_mmap_vmops;
6342 if (event->pmu->event_mapped)
6343 event->pmu->event_mapped(event, vma->vm_mm);
6348 static int perf_fasync(int fd, struct file *filp, int on)
6350 struct inode *inode = file_inode(filp);
6351 struct perf_event *event = filp->private_data;
6355 retval = fasync_helper(fd, filp, on, &event->fasync);
6356 inode_unlock(inode);
6364 static const struct file_operations perf_fops = {
6365 .llseek = no_llseek,
6366 .release = perf_release,
6369 .unlocked_ioctl = perf_ioctl,
6370 .compat_ioctl = perf_compat_ioctl,
6372 .fasync = perf_fasync,
6378 * If there's data, ensure we set the poll() state and publish everything
6379 * to user-space before waking everybody up.
6382 static inline struct fasync_struct **perf_event_fasync(struct perf_event *event)
6384 /* only the parent has fasync state */
6386 event = event->parent;
6387 return &event->fasync;
6390 void perf_event_wakeup(struct perf_event *event)
6392 ring_buffer_wakeup(event);
6394 if (event->pending_kill) {
6395 kill_fasync(perf_event_fasync(event), SIGIO, event->pending_kill);
6396 event->pending_kill = 0;
6400 static void perf_sigtrap(struct perf_event *event)
6403 * We'd expect this to only occur if the irq_work is delayed and either
6404 * ctx->task or current has changed in the meantime. This can be the
6405 * case on architectures that do not implement arch_irq_work_raise().
6407 if (WARN_ON_ONCE(event->ctx->task != current))
6411 * perf_pending_event() can race with the task exiting.
6413 if (current->flags & PF_EXITING)
6416 force_sig_perf((void __user *)event->pending_addr,
6417 event->attr.type, event->attr.sig_data);
6420 static void perf_pending_event_disable(struct perf_event *event)
6422 int cpu = READ_ONCE(event->pending_disable);
6427 if (cpu == smp_processor_id()) {
6428 WRITE_ONCE(event->pending_disable, -1);
6430 if (event->attr.sigtrap) {
6431 perf_sigtrap(event);
6432 atomic_set_release(&event->event_limit, 1); /* rearm event */
6436 perf_event_disable_local(event);
6443 * perf_event_disable_inatomic()
6444 * @pending_disable = CPU-A;
6448 * @pending_disable = -1;
6451 * perf_event_disable_inatomic()
6452 * @pending_disable = CPU-B;
6453 * irq_work_queue(); // FAILS
6456 * perf_pending_event()
6458 * But the event runs on CPU-B and wants disabling there.
6460 irq_work_queue_on(&event->pending, cpu);
6463 static void perf_pending_event(struct irq_work *entry)
6465 struct perf_event *event = container_of(entry, struct perf_event, pending);
6468 rctx = perf_swevent_get_recursion_context();
6470 * If we 'fail' here, that's OK, it means recursion is already disabled
6471 * and we won't recurse 'further'.
6474 perf_pending_event_disable(event);
6476 if (event->pending_wakeup) {
6477 event->pending_wakeup = 0;
6478 perf_event_wakeup(event);
6482 perf_swevent_put_recursion_context(rctx);
6486 * We assume there is only KVM supporting the callbacks.
6487 * Later on, we might change it to a list if there is
6488 * another virtualization implementation supporting the callbacks.
6490 struct perf_guest_info_callbacks *perf_guest_cbs;
6492 int perf_register_guest_info_callbacks(struct perf_guest_info_callbacks *cbs)
6494 perf_guest_cbs = cbs;
6497 EXPORT_SYMBOL_GPL(perf_register_guest_info_callbacks);
6499 int perf_unregister_guest_info_callbacks(struct perf_guest_info_callbacks *cbs)
6501 perf_guest_cbs = NULL;
6504 EXPORT_SYMBOL_GPL(perf_unregister_guest_info_callbacks);
6507 perf_output_sample_regs(struct perf_output_handle *handle,
6508 struct pt_regs *regs, u64 mask)
6511 DECLARE_BITMAP(_mask, 64);
6513 bitmap_from_u64(_mask, mask);
6514 for_each_set_bit(bit, _mask, sizeof(mask) * BITS_PER_BYTE) {
6517 val = perf_reg_value(regs, bit);
6518 perf_output_put(handle, val);
6522 static void perf_sample_regs_user(struct perf_regs *regs_user,
6523 struct pt_regs *regs)
6525 if (user_mode(regs)) {
6526 regs_user->abi = perf_reg_abi(current);
6527 regs_user->regs = regs;
6528 } else if (!(current->flags & PF_KTHREAD)) {
6529 perf_get_regs_user(regs_user, regs);
6531 regs_user->abi = PERF_SAMPLE_REGS_ABI_NONE;
6532 regs_user->regs = NULL;
6536 static void perf_sample_regs_intr(struct perf_regs *regs_intr,
6537 struct pt_regs *regs)
6539 regs_intr->regs = regs;
6540 regs_intr->abi = perf_reg_abi(current);
6545 * Get remaining task size from user stack pointer.
6547 * It'd be better to take stack vma map and limit this more
6548 * precisely, but there's no way to get it safely under interrupt,
6549 * so using TASK_SIZE as limit.
6551 static u64 perf_ustack_task_size(struct pt_regs *regs)
6553 unsigned long addr = perf_user_stack_pointer(regs);
6555 if (!addr || addr >= TASK_SIZE)
6558 return TASK_SIZE - addr;
6562 perf_sample_ustack_size(u16 stack_size, u16 header_size,
6563 struct pt_regs *regs)
6567 /* No regs, no stack pointer, no dump. */
6572 * Check if we fit in with the requested stack size into the:
6574 * If we don't, we limit the size to the TASK_SIZE.
6576 * - remaining sample size
6577 * If we don't, we customize the stack size to
6578 * fit in to the remaining sample size.
6581 task_size = min((u64) USHRT_MAX, perf_ustack_task_size(regs));
6582 stack_size = min(stack_size, (u16) task_size);
6584 /* Current header size plus static size and dynamic size. */
6585 header_size += 2 * sizeof(u64);
6587 /* Do we fit in with the current stack dump size? */
6588 if ((u16) (header_size + stack_size) < header_size) {
6590 * If we overflow the maximum size for the sample,
6591 * we customize the stack dump size to fit in.
6593 stack_size = USHRT_MAX - header_size - sizeof(u64);
6594 stack_size = round_up(stack_size, sizeof(u64));
6601 perf_output_sample_ustack(struct perf_output_handle *handle, u64 dump_size,
6602 struct pt_regs *regs)
6604 /* Case of a kernel thread, nothing to dump */
6607 perf_output_put(handle, size);
6617 * - the size requested by user or the best one we can fit
6618 * in to the sample max size
6620 * - user stack dump data
6622 * - the actual dumped size
6626 perf_output_put(handle, dump_size);
6629 sp = perf_user_stack_pointer(regs);
6630 fs = force_uaccess_begin();
6631 rem = __output_copy_user(handle, (void *) sp, dump_size);
6632 force_uaccess_end(fs);
6633 dyn_size = dump_size - rem;
6635 perf_output_skip(handle, rem);
6638 perf_output_put(handle, dyn_size);
6642 static unsigned long perf_prepare_sample_aux(struct perf_event *event,
6643 struct perf_sample_data *data,
6646 struct perf_event *sampler = event->aux_event;
6647 struct perf_buffer *rb;
6654 if (WARN_ON_ONCE(READ_ONCE(sampler->state) != PERF_EVENT_STATE_ACTIVE))
6657 if (WARN_ON_ONCE(READ_ONCE(sampler->oncpu) != smp_processor_id()))
6660 rb = ring_buffer_get(sampler->parent ? sampler->parent : sampler);
6665 * If this is an NMI hit inside sampling code, don't take
6666 * the sample. See also perf_aux_sample_output().
6668 if (READ_ONCE(rb->aux_in_sampling)) {
6671 size = min_t(size_t, size, perf_aux_size(rb));
6672 data->aux_size = ALIGN(size, sizeof(u64));
6674 ring_buffer_put(rb);
6677 return data->aux_size;
6680 static long perf_pmu_snapshot_aux(struct perf_buffer *rb,
6681 struct perf_event *event,
6682 struct perf_output_handle *handle,
6685 unsigned long flags;
6689 * Normal ->start()/->stop() callbacks run in IRQ mode in scheduler
6690 * paths. If we start calling them in NMI context, they may race with
6691 * the IRQ ones, that is, for example, re-starting an event that's just
6692 * been stopped, which is why we're using a separate callback that
6693 * doesn't change the event state.
6695 * IRQs need to be disabled to prevent IPIs from racing with us.
6697 local_irq_save(flags);
6699 * Guard against NMI hits inside the critical section;
6700 * see also perf_prepare_sample_aux().
6702 WRITE_ONCE(rb->aux_in_sampling, 1);
6705 ret = event->pmu->snapshot_aux(event, handle, size);
6708 WRITE_ONCE(rb->aux_in_sampling, 0);
6709 local_irq_restore(flags);
6714 static void perf_aux_sample_output(struct perf_event *event,
6715 struct perf_output_handle *handle,
6716 struct perf_sample_data *data)
6718 struct perf_event *sampler = event->aux_event;
6719 struct perf_buffer *rb;
6723 if (WARN_ON_ONCE(!sampler || !data->aux_size))
6726 rb = ring_buffer_get(sampler->parent ? sampler->parent : sampler);
6730 size = perf_pmu_snapshot_aux(rb, sampler, handle, data->aux_size);
6733 * An error here means that perf_output_copy() failed (returned a
6734 * non-zero surplus that it didn't copy), which in its current
6735 * enlightened implementation is not possible. If that changes, we'd
6738 if (WARN_ON_ONCE(size < 0))
6742 * The pad comes from ALIGN()ing data->aux_size up to u64 in
6743 * perf_prepare_sample_aux(), so should not be more than that.
6745 pad = data->aux_size - size;
6746 if (WARN_ON_ONCE(pad >= sizeof(u64)))
6751 perf_output_copy(handle, &zero, pad);
6755 ring_buffer_put(rb);
6758 static void __perf_event_header__init_id(struct perf_event_header *header,
6759 struct perf_sample_data *data,
6760 struct perf_event *event)
6762 u64 sample_type = event->attr.sample_type;
6764 data->type = sample_type;
6765 header->size += event->id_header_size;
6767 if (sample_type & PERF_SAMPLE_TID) {
6768 /* namespace issues */
6769 data->tid_entry.pid = perf_event_pid(event, current);
6770 data->tid_entry.tid = perf_event_tid(event, current);
6773 if (sample_type & PERF_SAMPLE_TIME)
6774 data->time = perf_event_clock(event);
6776 if (sample_type & (PERF_SAMPLE_ID | PERF_SAMPLE_IDENTIFIER))
6777 data->id = primary_event_id(event);
6779 if (sample_type & PERF_SAMPLE_STREAM_ID)
6780 data->stream_id = event->id;
6782 if (sample_type & PERF_SAMPLE_CPU) {
6783 data->cpu_entry.cpu = raw_smp_processor_id();
6784 data->cpu_entry.reserved = 0;
6788 void perf_event_header__init_id(struct perf_event_header *header,
6789 struct perf_sample_data *data,
6790 struct perf_event *event)
6792 if (event->attr.sample_id_all)
6793 __perf_event_header__init_id(header, data, event);
6796 static void __perf_event__output_id_sample(struct perf_output_handle *handle,
6797 struct perf_sample_data *data)
6799 u64 sample_type = data->type;
6801 if (sample_type & PERF_SAMPLE_TID)
6802 perf_output_put(handle, data->tid_entry);
6804 if (sample_type & PERF_SAMPLE_TIME)
6805 perf_output_put(handle, data->time);
6807 if (sample_type & PERF_SAMPLE_ID)
6808 perf_output_put(handle, data->id);
6810 if (sample_type & PERF_SAMPLE_STREAM_ID)
6811 perf_output_put(handle, data->stream_id);
6813 if (sample_type & PERF_SAMPLE_CPU)
6814 perf_output_put(handle, data->cpu_entry);
6816 if (sample_type & PERF_SAMPLE_IDENTIFIER)
6817 perf_output_put(handle, data->id);
6820 void perf_event__output_id_sample(struct perf_event *event,
6821 struct perf_output_handle *handle,
6822 struct perf_sample_data *sample)
6824 if (event->attr.sample_id_all)
6825 __perf_event__output_id_sample(handle, sample);
6828 static void perf_output_read_one(struct perf_output_handle *handle,
6829 struct perf_event *event,
6830 u64 enabled, u64 running)
6832 u64 read_format = event->attr.read_format;
6836 values[n++] = perf_event_count(event);
6837 if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED) {
6838 values[n++] = enabled +
6839 atomic64_read(&event->child_total_time_enabled);
6841 if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING) {
6842 values[n++] = running +
6843 atomic64_read(&event->child_total_time_running);
6845 if (read_format & PERF_FORMAT_ID)
6846 values[n++] = primary_event_id(event);
6848 __output_copy(handle, values, n * sizeof(u64));
6851 static void perf_output_read_group(struct perf_output_handle *handle,
6852 struct perf_event *event,
6853 u64 enabled, u64 running)
6855 struct perf_event *leader = event->group_leader, *sub;
6856 u64 read_format = event->attr.read_format;
6860 values[n++] = 1 + leader->nr_siblings;
6862 if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED)
6863 values[n++] = enabled;
6865 if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING)
6866 values[n++] = running;
6868 if ((leader != event) &&
6869 (leader->state == PERF_EVENT_STATE_ACTIVE))
6870 leader->pmu->read(leader);
6872 values[n++] = perf_event_count(leader);
6873 if (read_format & PERF_FORMAT_ID)
6874 values[n++] = primary_event_id(leader);
6876 __output_copy(handle, values, n * sizeof(u64));
6878 for_each_sibling_event(sub, leader) {
6881 if ((sub != event) &&
6882 (sub->state == PERF_EVENT_STATE_ACTIVE))
6883 sub->pmu->read(sub);
6885 values[n++] = perf_event_count(sub);
6886 if (read_format & PERF_FORMAT_ID)
6887 values[n++] = primary_event_id(sub);
6889 __output_copy(handle, values, n * sizeof(u64));
6893 #define PERF_FORMAT_TOTAL_TIMES (PERF_FORMAT_TOTAL_TIME_ENABLED|\
6894 PERF_FORMAT_TOTAL_TIME_RUNNING)
6897 * XXX PERF_SAMPLE_READ vs inherited events seems difficult.
6899 * The problem is that its both hard and excessively expensive to iterate the
6900 * child list, not to mention that its impossible to IPI the children running
6901 * on another CPU, from interrupt/NMI context.
6903 static void perf_output_read(struct perf_output_handle *handle,
6904 struct perf_event *event)
6906 u64 enabled = 0, running = 0, now;
6907 u64 read_format = event->attr.read_format;
6910 * compute total_time_enabled, total_time_running
6911 * based on snapshot values taken when the event
6912 * was last scheduled in.
6914 * we cannot simply called update_context_time()
6915 * because of locking issue as we are called in
6918 if (read_format & PERF_FORMAT_TOTAL_TIMES)
6919 calc_timer_values(event, &now, &enabled, &running);
6921 if (event->attr.read_format & PERF_FORMAT_GROUP)
6922 perf_output_read_group(handle, event, enabled, running);
6924 perf_output_read_one(handle, event, enabled, running);
6927 static inline bool perf_sample_save_hw_index(struct perf_event *event)
6929 return event->attr.branch_sample_type & PERF_SAMPLE_BRANCH_HW_INDEX;
6932 void perf_output_sample(struct perf_output_handle *handle,
6933 struct perf_event_header *header,
6934 struct perf_sample_data *data,
6935 struct perf_event *event)
6937 u64 sample_type = data->type;
6939 perf_output_put(handle, *header);
6941 if (sample_type & PERF_SAMPLE_IDENTIFIER)
6942 perf_output_put(handle, data->id);
6944 if (sample_type & PERF_SAMPLE_IP)
6945 perf_output_put(handle, data->ip);
6947 if (sample_type & PERF_SAMPLE_TID)
6948 perf_output_put(handle, data->tid_entry);
6950 if (sample_type & PERF_SAMPLE_TIME)
6951 perf_output_put(handle, data->time);
6953 if (sample_type & PERF_SAMPLE_ADDR)
6954 perf_output_put(handle, data->addr);
6956 if (sample_type & PERF_SAMPLE_ID)
6957 perf_output_put(handle, data->id);
6959 if (sample_type & PERF_SAMPLE_STREAM_ID)
6960 perf_output_put(handle, data->stream_id);
6962 if (sample_type & PERF_SAMPLE_CPU)
6963 perf_output_put(handle, data->cpu_entry);
6965 if (sample_type & PERF_SAMPLE_PERIOD)
6966 perf_output_put(handle, data->period);
6968 if (sample_type & PERF_SAMPLE_READ)
6969 perf_output_read(handle, event);
6971 if (sample_type & PERF_SAMPLE_CALLCHAIN) {
6974 size += data->callchain->nr;
6975 size *= sizeof(u64);
6976 __output_copy(handle, data->callchain, size);
6979 if (sample_type & PERF_SAMPLE_RAW) {
6980 struct perf_raw_record *raw = data->raw;
6983 struct perf_raw_frag *frag = &raw->frag;
6985 perf_output_put(handle, raw->size);
6988 __output_custom(handle, frag->copy,
6989 frag->data, frag->size);
6991 __output_copy(handle, frag->data,
6994 if (perf_raw_frag_last(frag))
6999 __output_skip(handle, NULL, frag->pad);
7005 .size = sizeof(u32),
7008 perf_output_put(handle, raw);
7012 if (sample_type & PERF_SAMPLE_BRANCH_STACK) {
7013 if (data->br_stack) {
7016 size = data->br_stack->nr
7017 * sizeof(struct perf_branch_entry);
7019 perf_output_put(handle, data->br_stack->nr);
7020 if (perf_sample_save_hw_index(event))
7021 perf_output_put(handle, data->br_stack->hw_idx);
7022 perf_output_copy(handle, data->br_stack->entries, size);
7025 * we always store at least the value of nr
7028 perf_output_put(handle, nr);
7032 if (sample_type & PERF_SAMPLE_REGS_USER) {
7033 u64 abi = data->regs_user.abi;
7036 * If there are no regs to dump, notice it through
7037 * first u64 being zero (PERF_SAMPLE_REGS_ABI_NONE).
7039 perf_output_put(handle, abi);
7042 u64 mask = event->attr.sample_regs_user;
7043 perf_output_sample_regs(handle,
7044 data->regs_user.regs,
7049 if (sample_type & PERF_SAMPLE_STACK_USER) {
7050 perf_output_sample_ustack(handle,
7051 data->stack_user_size,
7052 data->regs_user.regs);
7055 if (sample_type & PERF_SAMPLE_WEIGHT_TYPE)
7056 perf_output_put(handle, data->weight.full);
7058 if (sample_type & PERF_SAMPLE_DATA_SRC)
7059 perf_output_put(handle, data->data_src.val);
7061 if (sample_type & PERF_SAMPLE_TRANSACTION)
7062 perf_output_put(handle, data->txn);
7064 if (sample_type & PERF_SAMPLE_REGS_INTR) {
7065 u64 abi = data->regs_intr.abi;
7067 * If there are no regs to dump, notice it through
7068 * first u64 being zero (PERF_SAMPLE_REGS_ABI_NONE).
7070 perf_output_put(handle, abi);
7073 u64 mask = event->attr.sample_regs_intr;
7075 perf_output_sample_regs(handle,
7076 data->regs_intr.regs,
7081 if (sample_type & PERF_SAMPLE_PHYS_ADDR)
7082 perf_output_put(handle, data->phys_addr);
7084 if (sample_type & PERF_SAMPLE_CGROUP)
7085 perf_output_put(handle, data->cgroup);
7087 if (sample_type & PERF_SAMPLE_DATA_PAGE_SIZE)
7088 perf_output_put(handle, data->data_page_size);
7090 if (sample_type & PERF_SAMPLE_CODE_PAGE_SIZE)
7091 perf_output_put(handle, data->code_page_size);
7093 if (sample_type & PERF_SAMPLE_AUX) {
7094 perf_output_put(handle, data->aux_size);
7097 perf_aux_sample_output(event, handle, data);
7100 if (!event->attr.watermark) {
7101 int wakeup_events = event->attr.wakeup_events;
7103 if (wakeup_events) {
7104 struct perf_buffer *rb = handle->rb;
7105 int events = local_inc_return(&rb->events);
7107 if (events >= wakeup_events) {
7108 local_sub(wakeup_events, &rb->events);
7109 local_inc(&rb->wakeup);
7115 static u64 perf_virt_to_phys(u64 virt)
7118 struct page *p = NULL;
7123 if (virt >= TASK_SIZE) {
7124 /* If it's vmalloc()d memory, leave phys_addr as 0 */
7125 if (virt_addr_valid((void *)(uintptr_t)virt) &&
7126 !(virt >= VMALLOC_START && virt < VMALLOC_END))
7127 phys_addr = (u64)virt_to_phys((void *)(uintptr_t)virt);
7130 * Walking the pages tables for user address.
7131 * Interrupts are disabled, so it prevents any tear down
7132 * of the page tables.
7133 * Try IRQ-safe get_user_page_fast_only first.
7134 * If failed, leave phys_addr as 0.
7136 if (current->mm != NULL) {
7137 pagefault_disable();
7138 if (get_user_page_fast_only(virt, 0, &p))
7139 phys_addr = page_to_phys(p) + virt % PAGE_SIZE;
7151 * Return the pagetable size of a given virtual address.
7153 static u64 perf_get_pgtable_size(struct mm_struct *mm, unsigned long addr)
7157 #ifdef CONFIG_HAVE_FAST_GUP
7164 pgdp = pgd_offset(mm, addr);
7165 pgd = READ_ONCE(*pgdp);
7170 return pgd_leaf_size(pgd);
7172 p4dp = p4d_offset_lockless(pgdp, pgd, addr);
7173 p4d = READ_ONCE(*p4dp);
7174 if (!p4d_present(p4d))
7178 return p4d_leaf_size(p4d);
7180 pudp = pud_offset_lockless(p4dp, p4d, addr);
7181 pud = READ_ONCE(*pudp);
7182 if (!pud_present(pud))
7186 return pud_leaf_size(pud);
7188 pmdp = pmd_offset_lockless(pudp, pud, addr);
7189 pmd = READ_ONCE(*pmdp);
7190 if (!pmd_present(pmd))
7194 return pmd_leaf_size(pmd);
7196 ptep = pte_offset_map(&pmd, addr);
7197 pte = ptep_get_lockless(ptep);
7198 if (pte_present(pte))
7199 size = pte_leaf_size(pte);
7201 #endif /* CONFIG_HAVE_FAST_GUP */
7206 static u64 perf_get_page_size(unsigned long addr)
7208 struct mm_struct *mm;
7209 unsigned long flags;
7216 * Software page-table walkers must disable IRQs,
7217 * which prevents any tear down of the page tables.
7219 local_irq_save(flags);
7224 * For kernel threads and the like, use init_mm so that
7225 * we can find kernel memory.
7230 size = perf_get_pgtable_size(mm, addr);
7232 local_irq_restore(flags);
7237 static struct perf_callchain_entry __empty_callchain = { .nr = 0, };
7239 struct perf_callchain_entry *
7240 perf_callchain(struct perf_event *event, struct pt_regs *regs)
7242 bool kernel = !event->attr.exclude_callchain_kernel;
7243 bool user = !event->attr.exclude_callchain_user;
7244 /* Disallow cross-task user callchains. */
7245 bool crosstask = event->ctx->task && event->ctx->task != current;
7246 const u32 max_stack = event->attr.sample_max_stack;
7247 struct perf_callchain_entry *callchain;
7249 if (!kernel && !user)
7250 return &__empty_callchain;
7252 callchain = get_perf_callchain(regs, 0, kernel, user,
7253 max_stack, crosstask, true);
7254 return callchain ?: &__empty_callchain;
7257 void perf_prepare_sample(struct perf_event_header *header,
7258 struct perf_sample_data *data,
7259 struct perf_event *event,
7260 struct pt_regs *regs)
7262 u64 sample_type = event->attr.sample_type;
7264 header->type = PERF_RECORD_SAMPLE;
7265 header->size = sizeof(*header) + event->header_size;
7268 header->misc |= perf_misc_flags(regs);
7270 __perf_event_header__init_id(header, data, event);
7272 if (sample_type & (PERF_SAMPLE_IP | PERF_SAMPLE_CODE_PAGE_SIZE))
7273 data->ip = perf_instruction_pointer(regs);
7275 if (sample_type & PERF_SAMPLE_CALLCHAIN) {
7278 if (!(sample_type & __PERF_SAMPLE_CALLCHAIN_EARLY))
7279 data->callchain = perf_callchain(event, regs);
7281 size += data->callchain->nr;
7283 header->size += size * sizeof(u64);
7286 if (sample_type & PERF_SAMPLE_RAW) {
7287 struct perf_raw_record *raw = data->raw;
7291 struct perf_raw_frag *frag = &raw->frag;
7296 if (perf_raw_frag_last(frag))
7301 size = round_up(sum + sizeof(u32), sizeof(u64));
7302 raw->size = size - sizeof(u32);
7303 frag->pad = raw->size - sum;
7308 header->size += size;
7311 if (sample_type & PERF_SAMPLE_BRANCH_STACK) {
7312 int size = sizeof(u64); /* nr */
7313 if (data->br_stack) {
7314 if (perf_sample_save_hw_index(event))
7315 size += sizeof(u64);
7317 size += data->br_stack->nr
7318 * sizeof(struct perf_branch_entry);
7320 header->size += size;
7323 if (sample_type & (PERF_SAMPLE_REGS_USER | PERF_SAMPLE_STACK_USER))
7324 perf_sample_regs_user(&data->regs_user, regs);
7326 if (sample_type & PERF_SAMPLE_REGS_USER) {
7327 /* regs dump ABI info */
7328 int size = sizeof(u64);
7330 if (data->regs_user.regs) {
7331 u64 mask = event->attr.sample_regs_user;
7332 size += hweight64(mask) * sizeof(u64);
7335 header->size += size;
7338 if (sample_type & PERF_SAMPLE_STACK_USER) {
7340 * Either we need PERF_SAMPLE_STACK_USER bit to be always
7341 * processed as the last one or have additional check added
7342 * in case new sample type is added, because we could eat
7343 * up the rest of the sample size.
7345 u16 stack_size = event->attr.sample_stack_user;
7346 u16 size = sizeof(u64);
7348 stack_size = perf_sample_ustack_size(stack_size, header->size,
7349 data->regs_user.regs);
7352 * If there is something to dump, add space for the dump
7353 * itself and for the field that tells the dynamic size,
7354 * which is how many have been actually dumped.
7357 size += sizeof(u64) + stack_size;
7359 data->stack_user_size = stack_size;
7360 header->size += size;
7363 if (sample_type & PERF_SAMPLE_REGS_INTR) {
7364 /* regs dump ABI info */
7365 int size = sizeof(u64);
7367 perf_sample_regs_intr(&data->regs_intr, regs);
7369 if (data->regs_intr.regs) {
7370 u64 mask = event->attr.sample_regs_intr;
7372 size += hweight64(mask) * sizeof(u64);
7375 header->size += size;
7378 if (sample_type & PERF_SAMPLE_PHYS_ADDR)
7379 data->phys_addr = perf_virt_to_phys(data->addr);
7381 #ifdef CONFIG_CGROUP_PERF
7382 if (sample_type & PERF_SAMPLE_CGROUP) {
7383 struct cgroup *cgrp;
7385 /* protected by RCU */
7386 cgrp = task_css_check(current, perf_event_cgrp_id, 1)->cgroup;
7387 data->cgroup = cgroup_id(cgrp);
7392 * PERF_DATA_PAGE_SIZE requires PERF_SAMPLE_ADDR. If the user doesn't
7393 * require PERF_SAMPLE_ADDR, kernel implicitly retrieve the data->addr,
7394 * but the value will not dump to the userspace.
7396 if (sample_type & PERF_SAMPLE_DATA_PAGE_SIZE)
7397 data->data_page_size = perf_get_page_size(data->addr);
7399 if (sample_type & PERF_SAMPLE_CODE_PAGE_SIZE)
7400 data->code_page_size = perf_get_page_size(data->ip);
7402 if (sample_type & PERF_SAMPLE_AUX) {
7405 header->size += sizeof(u64); /* size */
7408 * Given the 16bit nature of header::size, an AUX sample can
7409 * easily overflow it, what with all the preceding sample bits.
7410 * Make sure this doesn't happen by using up to U16_MAX bytes
7411 * per sample in total (rounded down to 8 byte boundary).
7413 size = min_t(size_t, U16_MAX - header->size,
7414 event->attr.aux_sample_size);
7415 size = rounddown(size, 8);
7416 size = perf_prepare_sample_aux(event, data, size);
7418 WARN_ON_ONCE(size + header->size > U16_MAX);
7419 header->size += size;
7422 * If you're adding more sample types here, you likely need to do
7423 * something about the overflowing header::size, like repurpose the
7424 * lowest 3 bits of size, which should be always zero at the moment.
7425 * This raises a more important question, do we really need 512k sized
7426 * samples and why, so good argumentation is in order for whatever you
7429 WARN_ON_ONCE(header->size & 7);
7432 static __always_inline int
7433 __perf_event_output(struct perf_event *event,
7434 struct perf_sample_data *data,
7435 struct pt_regs *regs,
7436 int (*output_begin)(struct perf_output_handle *,
7437 struct perf_sample_data *,
7438 struct perf_event *,
7441 struct perf_output_handle handle;
7442 struct perf_event_header header;
7445 /* protect the callchain buffers */
7448 perf_prepare_sample(&header, data, event, regs);
7450 err = output_begin(&handle, data, event, header.size);
7454 perf_output_sample(&handle, &header, data, event);
7456 perf_output_end(&handle);
7464 perf_event_output_forward(struct perf_event *event,
7465 struct perf_sample_data *data,
7466 struct pt_regs *regs)
7468 __perf_event_output(event, data, regs, perf_output_begin_forward);
7472 perf_event_output_backward(struct perf_event *event,
7473 struct perf_sample_data *data,
7474 struct pt_regs *regs)
7476 __perf_event_output(event, data, regs, perf_output_begin_backward);
7480 perf_event_output(struct perf_event *event,
7481 struct perf_sample_data *data,
7482 struct pt_regs *regs)
7484 return __perf_event_output(event, data, regs, perf_output_begin);
7491 struct perf_read_event {
7492 struct perf_event_header header;
7499 perf_event_read_event(struct perf_event *event,
7500 struct task_struct *task)
7502 struct perf_output_handle handle;
7503 struct perf_sample_data sample;
7504 struct perf_read_event read_event = {
7506 .type = PERF_RECORD_READ,
7508 .size = sizeof(read_event) + event->read_size,
7510 .pid = perf_event_pid(event, task),
7511 .tid = perf_event_tid(event, task),
7515 perf_event_header__init_id(&read_event.header, &sample, event);
7516 ret = perf_output_begin(&handle, &sample, event, read_event.header.size);
7520 perf_output_put(&handle, read_event);
7521 perf_output_read(&handle, event);
7522 perf_event__output_id_sample(event, &handle, &sample);
7524 perf_output_end(&handle);
7527 typedef void (perf_iterate_f)(struct perf_event *event, void *data);
7530 perf_iterate_ctx(struct perf_event_context *ctx,
7531 perf_iterate_f output,
7532 void *data, bool all)
7534 struct perf_event *event;
7536 list_for_each_entry_rcu(event, &ctx->event_list, event_entry) {
7538 if (event->state < PERF_EVENT_STATE_INACTIVE)
7540 if (!event_filter_match(event))
7544 output(event, data);
7548 static void perf_iterate_sb_cpu(perf_iterate_f output, void *data)
7550 struct pmu_event_list *pel = this_cpu_ptr(&pmu_sb_events);
7551 struct perf_event *event;
7553 list_for_each_entry_rcu(event, &pel->list, sb_list) {
7555 * Skip events that are not fully formed yet; ensure that
7556 * if we observe event->ctx, both event and ctx will be
7557 * complete enough. See perf_install_in_context().
7559 if (!smp_load_acquire(&event->ctx))
7562 if (event->state < PERF_EVENT_STATE_INACTIVE)
7564 if (!event_filter_match(event))
7566 output(event, data);
7571 * Iterate all events that need to receive side-band events.
7573 * For new callers; ensure that account_pmu_sb_event() includes
7574 * your event, otherwise it might not get delivered.
7577 perf_iterate_sb(perf_iterate_f output, void *data,
7578 struct perf_event_context *task_ctx)
7580 struct perf_event_context *ctx;
7587 * If we have task_ctx != NULL we only notify the task context itself.
7588 * The task_ctx is set only for EXIT events before releasing task
7592 perf_iterate_ctx(task_ctx, output, data, false);
7596 perf_iterate_sb_cpu(output, data);
7598 for_each_task_context_nr(ctxn) {
7599 ctx = rcu_dereference(current->perf_event_ctxp[ctxn]);
7601 perf_iterate_ctx(ctx, output, data, false);
7609 * Clear all file-based filters at exec, they'll have to be
7610 * re-instated when/if these objects are mmapped again.
7612 static void perf_event_addr_filters_exec(struct perf_event *event, void *data)
7614 struct perf_addr_filters_head *ifh = perf_event_addr_filters(event);
7615 struct perf_addr_filter *filter;
7616 unsigned int restart = 0, count = 0;
7617 unsigned long flags;
7619 if (!has_addr_filter(event))
7622 raw_spin_lock_irqsave(&ifh->lock, flags);
7623 list_for_each_entry(filter, &ifh->list, entry) {
7624 if (filter->path.dentry) {
7625 event->addr_filter_ranges[count].start = 0;
7626 event->addr_filter_ranges[count].size = 0;
7634 event->addr_filters_gen++;
7635 raw_spin_unlock_irqrestore(&ifh->lock, flags);
7638 perf_event_stop(event, 1);
7641 void perf_event_exec(void)
7643 struct perf_event_context *ctx;
7646 for_each_task_context_nr(ctxn) {
7647 perf_event_enable_on_exec(ctxn);
7648 perf_event_remove_on_exec(ctxn);
7651 ctx = rcu_dereference(current->perf_event_ctxp[ctxn]);
7653 perf_iterate_ctx(ctx, perf_event_addr_filters_exec,
7660 struct remote_output {
7661 struct perf_buffer *rb;
7665 static void __perf_event_output_stop(struct perf_event *event, void *data)
7667 struct perf_event *parent = event->parent;
7668 struct remote_output *ro = data;
7669 struct perf_buffer *rb = ro->rb;
7670 struct stop_event_data sd = {
7674 if (!has_aux(event))
7681 * In case of inheritance, it will be the parent that links to the
7682 * ring-buffer, but it will be the child that's actually using it.
7684 * We are using event::rb to determine if the event should be stopped,
7685 * however this may race with ring_buffer_attach() (through set_output),
7686 * which will make us skip the event that actually needs to be stopped.
7687 * So ring_buffer_attach() has to stop an aux event before re-assigning
7690 if (rcu_dereference(parent->rb) == rb)
7691 ro->err = __perf_event_stop(&sd);
7694 static int __perf_pmu_output_stop(void *info)
7696 struct perf_event *event = info;
7697 struct pmu *pmu = event->ctx->pmu;
7698 struct perf_cpu_context *cpuctx = this_cpu_ptr(pmu->pmu_cpu_context);
7699 struct remote_output ro = {
7704 perf_iterate_ctx(&cpuctx->ctx, __perf_event_output_stop, &ro, false);
7705 if (cpuctx->task_ctx)
7706 perf_iterate_ctx(cpuctx->task_ctx, __perf_event_output_stop,
7713 static void perf_pmu_output_stop(struct perf_event *event)
7715 struct perf_event *iter;
7720 list_for_each_entry_rcu(iter, &event->rb->event_list, rb_entry) {
7722 * For per-CPU events, we need to make sure that neither they
7723 * nor their children are running; for cpu==-1 events it's
7724 * sufficient to stop the event itself if it's active, since
7725 * it can't have children.
7729 cpu = READ_ONCE(iter->oncpu);
7734 err = cpu_function_call(cpu, __perf_pmu_output_stop, event);
7735 if (err == -EAGAIN) {
7744 * task tracking -- fork/exit
7746 * enabled by: attr.comm | attr.mmap | attr.mmap2 | attr.mmap_data | attr.task
7749 struct perf_task_event {
7750 struct task_struct *task;
7751 struct perf_event_context *task_ctx;
7754 struct perf_event_header header;
7764 static int perf_event_task_match(struct perf_event *event)
7766 return event->attr.comm || event->attr.mmap ||
7767 event->attr.mmap2 || event->attr.mmap_data ||
7771 static void perf_event_task_output(struct perf_event *event,
7774 struct perf_task_event *task_event = data;
7775 struct perf_output_handle handle;
7776 struct perf_sample_data sample;
7777 struct task_struct *task = task_event->task;
7778 int ret, size = task_event->event_id.header.size;
7780 if (!perf_event_task_match(event))
7783 perf_event_header__init_id(&task_event->event_id.header, &sample, event);
7785 ret = perf_output_begin(&handle, &sample, event,
7786 task_event->event_id.header.size);
7790 task_event->event_id.pid = perf_event_pid(event, task);
7791 task_event->event_id.tid = perf_event_tid(event, task);
7793 if (task_event->event_id.header.type == PERF_RECORD_EXIT) {
7794 task_event->event_id.ppid = perf_event_pid(event,
7796 task_event->event_id.ptid = perf_event_pid(event,
7798 } else { /* PERF_RECORD_FORK */
7799 task_event->event_id.ppid = perf_event_pid(event, current);
7800 task_event->event_id.ptid = perf_event_tid(event, current);
7803 task_event->event_id.time = perf_event_clock(event);
7805 perf_output_put(&handle, task_event->event_id);
7807 perf_event__output_id_sample(event, &handle, &sample);
7809 perf_output_end(&handle);
7811 task_event->event_id.header.size = size;
7814 static void perf_event_task(struct task_struct *task,
7815 struct perf_event_context *task_ctx,
7818 struct perf_task_event task_event;
7820 if (!atomic_read(&nr_comm_events) &&
7821 !atomic_read(&nr_mmap_events) &&
7822 !atomic_read(&nr_task_events))
7825 task_event = (struct perf_task_event){
7827 .task_ctx = task_ctx,
7830 .type = new ? PERF_RECORD_FORK : PERF_RECORD_EXIT,
7832 .size = sizeof(task_event.event_id),
7842 perf_iterate_sb(perf_event_task_output,
7847 void perf_event_fork(struct task_struct *task)
7849 perf_event_task(task, NULL, 1);
7850 perf_event_namespaces(task);
7857 struct perf_comm_event {
7858 struct task_struct *task;
7863 struct perf_event_header header;
7870 static int perf_event_comm_match(struct perf_event *event)
7872 return event->attr.comm;
7875 static void perf_event_comm_output(struct perf_event *event,
7878 struct perf_comm_event *comm_event = data;
7879 struct perf_output_handle handle;
7880 struct perf_sample_data sample;
7881 int size = comm_event->event_id.header.size;
7884 if (!perf_event_comm_match(event))
7887 perf_event_header__init_id(&comm_event->event_id.header, &sample, event);
7888 ret = perf_output_begin(&handle, &sample, event,
7889 comm_event->event_id.header.size);
7894 comm_event->event_id.pid = perf_event_pid(event, comm_event->task);
7895 comm_event->event_id.tid = perf_event_tid(event, comm_event->task);
7897 perf_output_put(&handle, comm_event->event_id);
7898 __output_copy(&handle, comm_event->comm,
7899 comm_event->comm_size);
7901 perf_event__output_id_sample(event, &handle, &sample);
7903 perf_output_end(&handle);
7905 comm_event->event_id.header.size = size;
7908 static void perf_event_comm_event(struct perf_comm_event *comm_event)
7910 char comm[TASK_COMM_LEN];
7913 memset(comm, 0, sizeof(comm));
7914 strlcpy(comm, comm_event->task->comm, sizeof(comm));
7915 size = ALIGN(strlen(comm)+1, sizeof(u64));
7917 comm_event->comm = comm;
7918 comm_event->comm_size = size;
7920 comm_event->event_id.header.size = sizeof(comm_event->event_id) + size;
7922 perf_iterate_sb(perf_event_comm_output,
7927 void perf_event_comm(struct task_struct *task, bool exec)
7929 struct perf_comm_event comm_event;
7931 if (!atomic_read(&nr_comm_events))
7934 comm_event = (struct perf_comm_event){
7940 .type = PERF_RECORD_COMM,
7941 .misc = exec ? PERF_RECORD_MISC_COMM_EXEC : 0,
7949 perf_event_comm_event(&comm_event);
7953 * namespaces tracking
7956 struct perf_namespaces_event {
7957 struct task_struct *task;
7960 struct perf_event_header header;
7965 struct perf_ns_link_info link_info[NR_NAMESPACES];
7969 static int perf_event_namespaces_match(struct perf_event *event)
7971 return event->attr.namespaces;
7974 static void perf_event_namespaces_output(struct perf_event *event,
7977 struct perf_namespaces_event *namespaces_event = data;
7978 struct perf_output_handle handle;
7979 struct perf_sample_data sample;
7980 u16 header_size = namespaces_event->event_id.header.size;
7983 if (!perf_event_namespaces_match(event))
7986 perf_event_header__init_id(&namespaces_event->event_id.header,
7988 ret = perf_output_begin(&handle, &sample, event,
7989 namespaces_event->event_id.header.size);
7993 namespaces_event->event_id.pid = perf_event_pid(event,
7994 namespaces_event->task);
7995 namespaces_event->event_id.tid = perf_event_tid(event,
7996 namespaces_event->task);
7998 perf_output_put(&handle, namespaces_event->event_id);
8000 perf_event__output_id_sample(event, &handle, &sample);
8002 perf_output_end(&handle);
8004 namespaces_event->event_id.header.size = header_size;
8007 static void perf_fill_ns_link_info(struct perf_ns_link_info *ns_link_info,
8008 struct task_struct *task,
8009 const struct proc_ns_operations *ns_ops)
8011 struct path ns_path;
8012 struct inode *ns_inode;
8015 error = ns_get_path(&ns_path, task, ns_ops);
8017 ns_inode = ns_path.dentry->d_inode;
8018 ns_link_info->dev = new_encode_dev(ns_inode->i_sb->s_dev);
8019 ns_link_info->ino = ns_inode->i_ino;
8024 void perf_event_namespaces(struct task_struct *task)
8026 struct perf_namespaces_event namespaces_event;
8027 struct perf_ns_link_info *ns_link_info;
8029 if (!atomic_read(&nr_namespaces_events))
8032 namespaces_event = (struct perf_namespaces_event){
8036 .type = PERF_RECORD_NAMESPACES,
8038 .size = sizeof(namespaces_event.event_id),
8042 .nr_namespaces = NR_NAMESPACES,
8043 /* .link_info[NR_NAMESPACES] */
8047 ns_link_info = namespaces_event.event_id.link_info;
8049 perf_fill_ns_link_info(&ns_link_info[MNT_NS_INDEX],
8050 task, &mntns_operations);
8052 #ifdef CONFIG_USER_NS
8053 perf_fill_ns_link_info(&ns_link_info[USER_NS_INDEX],
8054 task, &userns_operations);
8056 #ifdef CONFIG_NET_NS
8057 perf_fill_ns_link_info(&ns_link_info[NET_NS_INDEX],
8058 task, &netns_operations);
8060 #ifdef CONFIG_UTS_NS
8061 perf_fill_ns_link_info(&ns_link_info[UTS_NS_INDEX],
8062 task, &utsns_operations);
8064 #ifdef CONFIG_IPC_NS
8065 perf_fill_ns_link_info(&ns_link_info[IPC_NS_INDEX],
8066 task, &ipcns_operations);
8068 #ifdef CONFIG_PID_NS
8069 perf_fill_ns_link_info(&ns_link_info[PID_NS_INDEX],
8070 task, &pidns_operations);
8072 #ifdef CONFIG_CGROUPS
8073 perf_fill_ns_link_info(&ns_link_info[CGROUP_NS_INDEX],
8074 task, &cgroupns_operations);
8077 perf_iterate_sb(perf_event_namespaces_output,
8085 #ifdef CONFIG_CGROUP_PERF
8087 struct perf_cgroup_event {
8091 struct perf_event_header header;
8097 static int perf_event_cgroup_match(struct perf_event *event)
8099 return event->attr.cgroup;
8102 static void perf_event_cgroup_output(struct perf_event *event, void *data)
8104 struct perf_cgroup_event *cgroup_event = data;
8105 struct perf_output_handle handle;
8106 struct perf_sample_data sample;
8107 u16 header_size = cgroup_event->event_id.header.size;
8110 if (!perf_event_cgroup_match(event))
8113 perf_event_header__init_id(&cgroup_event->event_id.header,
8115 ret = perf_output_begin(&handle, &sample, event,
8116 cgroup_event->event_id.header.size);
8120 perf_output_put(&handle, cgroup_event->event_id);
8121 __output_copy(&handle, cgroup_event->path, cgroup_event->path_size);
8123 perf_event__output_id_sample(event, &handle, &sample);
8125 perf_output_end(&handle);
8127 cgroup_event->event_id.header.size = header_size;
8130 static void perf_event_cgroup(struct cgroup *cgrp)
8132 struct perf_cgroup_event cgroup_event;
8133 char path_enomem[16] = "//enomem";
8137 if (!atomic_read(&nr_cgroup_events))
8140 cgroup_event = (struct perf_cgroup_event){
8143 .type = PERF_RECORD_CGROUP,
8145 .size = sizeof(cgroup_event.event_id),
8147 .id = cgroup_id(cgrp),
8151 pathname = kmalloc(PATH_MAX, GFP_KERNEL);
8152 if (pathname == NULL) {
8153 cgroup_event.path = path_enomem;
8155 /* just to be sure to have enough space for alignment */
8156 cgroup_path(cgrp, pathname, PATH_MAX - sizeof(u64));
8157 cgroup_event.path = pathname;
8161 * Since our buffer works in 8 byte units we need to align our string
8162 * size to a multiple of 8. However, we must guarantee the tail end is
8163 * zero'd out to avoid leaking random bits to userspace.
8165 size = strlen(cgroup_event.path) + 1;
8166 while (!IS_ALIGNED(size, sizeof(u64)))
8167 cgroup_event.path[size++] = '\0';
8169 cgroup_event.event_id.header.size += size;
8170 cgroup_event.path_size = size;
8172 perf_iterate_sb(perf_event_cgroup_output,
8185 struct perf_mmap_event {
8186 struct vm_area_struct *vma;
8188 const char *file_name;
8194 u8 build_id[BUILD_ID_SIZE_MAX];
8198 struct perf_event_header header;
8208 static int perf_event_mmap_match(struct perf_event *event,
8211 struct perf_mmap_event *mmap_event = data;
8212 struct vm_area_struct *vma = mmap_event->vma;
8213 int executable = vma->vm_flags & VM_EXEC;
8215 return (!executable && event->attr.mmap_data) ||
8216 (executable && (event->attr.mmap || event->attr.mmap2));
8219 static void perf_event_mmap_output(struct perf_event *event,
8222 struct perf_mmap_event *mmap_event = data;
8223 struct perf_output_handle handle;
8224 struct perf_sample_data sample;
8225 int size = mmap_event->event_id.header.size;
8226 u32 type = mmap_event->event_id.header.type;
8230 if (!perf_event_mmap_match(event, data))
8233 if (event->attr.mmap2) {
8234 mmap_event->event_id.header.type = PERF_RECORD_MMAP2;
8235 mmap_event->event_id.header.size += sizeof(mmap_event->maj);
8236 mmap_event->event_id.header.size += sizeof(mmap_event->min);
8237 mmap_event->event_id.header.size += sizeof(mmap_event->ino);
8238 mmap_event->event_id.header.size += sizeof(mmap_event->ino_generation);
8239 mmap_event->event_id.header.size += sizeof(mmap_event->prot);
8240 mmap_event->event_id.header.size += sizeof(mmap_event->flags);
8243 perf_event_header__init_id(&mmap_event->event_id.header, &sample, event);
8244 ret = perf_output_begin(&handle, &sample, event,
8245 mmap_event->event_id.header.size);
8249 mmap_event->event_id.pid = perf_event_pid(event, current);
8250 mmap_event->event_id.tid = perf_event_tid(event, current);
8252 use_build_id = event->attr.build_id && mmap_event->build_id_size;
8254 if (event->attr.mmap2 && use_build_id)
8255 mmap_event->event_id.header.misc |= PERF_RECORD_MISC_MMAP_BUILD_ID;
8257 perf_output_put(&handle, mmap_event->event_id);
8259 if (event->attr.mmap2) {
8261 u8 size[4] = { (u8) mmap_event->build_id_size, 0, 0, 0 };
8263 __output_copy(&handle, size, 4);
8264 __output_copy(&handle, mmap_event->build_id, BUILD_ID_SIZE_MAX);
8266 perf_output_put(&handle, mmap_event->maj);
8267 perf_output_put(&handle, mmap_event->min);
8268 perf_output_put(&handle, mmap_event->ino);
8269 perf_output_put(&handle, mmap_event->ino_generation);
8271 perf_output_put(&handle, mmap_event->prot);
8272 perf_output_put(&handle, mmap_event->flags);
8275 __output_copy(&handle, mmap_event->file_name,
8276 mmap_event->file_size);
8278 perf_event__output_id_sample(event, &handle, &sample);
8280 perf_output_end(&handle);
8282 mmap_event->event_id.header.size = size;
8283 mmap_event->event_id.header.type = type;
8286 static void perf_event_mmap_event(struct perf_mmap_event *mmap_event)
8288 struct vm_area_struct *vma = mmap_event->vma;
8289 struct file *file = vma->vm_file;
8290 int maj = 0, min = 0;
8291 u64 ino = 0, gen = 0;
8292 u32 prot = 0, flags = 0;
8298 if (vma->vm_flags & VM_READ)
8300 if (vma->vm_flags & VM_WRITE)
8302 if (vma->vm_flags & VM_EXEC)
8305 if (vma->vm_flags & VM_MAYSHARE)
8308 flags = MAP_PRIVATE;
8310 if (vma->vm_flags & VM_DENYWRITE)
8311 flags |= MAP_DENYWRITE;
8312 if (vma->vm_flags & VM_MAYEXEC)
8313 flags |= MAP_EXECUTABLE;
8314 if (vma->vm_flags & VM_LOCKED)
8315 flags |= MAP_LOCKED;
8316 if (is_vm_hugetlb_page(vma))
8317 flags |= MAP_HUGETLB;
8320 struct inode *inode;
8323 buf = kmalloc(PATH_MAX, GFP_KERNEL);
8329 * d_path() works from the end of the rb backwards, so we
8330 * need to add enough zero bytes after the string to handle
8331 * the 64bit alignment we do later.
8333 name = file_path(file, buf, PATH_MAX - sizeof(u64));
8338 inode = file_inode(vma->vm_file);
8339 dev = inode->i_sb->s_dev;
8341 gen = inode->i_generation;
8347 if (vma->vm_ops && vma->vm_ops->name) {
8348 name = (char *) vma->vm_ops->name(vma);
8353 name = (char *)arch_vma_name(vma);
8357 if (vma->vm_start <= vma->vm_mm->start_brk &&
8358 vma->vm_end >= vma->vm_mm->brk) {
8362 if (vma->vm_start <= vma->vm_mm->start_stack &&
8363 vma->vm_end >= vma->vm_mm->start_stack) {
8373 strlcpy(tmp, name, sizeof(tmp));
8377 * Since our buffer works in 8 byte units we need to align our string
8378 * size to a multiple of 8. However, we must guarantee the tail end is
8379 * zero'd out to avoid leaking random bits to userspace.
8381 size = strlen(name)+1;
8382 while (!IS_ALIGNED(size, sizeof(u64)))
8383 name[size++] = '\0';
8385 mmap_event->file_name = name;
8386 mmap_event->file_size = size;
8387 mmap_event->maj = maj;
8388 mmap_event->min = min;
8389 mmap_event->ino = ino;
8390 mmap_event->ino_generation = gen;
8391 mmap_event->prot = prot;
8392 mmap_event->flags = flags;
8394 if (!(vma->vm_flags & VM_EXEC))
8395 mmap_event->event_id.header.misc |= PERF_RECORD_MISC_MMAP_DATA;
8397 mmap_event->event_id.header.size = sizeof(mmap_event->event_id) + size;
8399 if (atomic_read(&nr_build_id_events))
8400 build_id_parse(vma, mmap_event->build_id, &mmap_event->build_id_size);
8402 perf_iterate_sb(perf_event_mmap_output,
8410 * Check whether inode and address range match filter criteria.
8412 static bool perf_addr_filter_match(struct perf_addr_filter *filter,
8413 struct file *file, unsigned long offset,
8416 /* d_inode(NULL) won't be equal to any mapped user-space file */
8417 if (!filter->path.dentry)
8420 if (d_inode(filter->path.dentry) != file_inode(file))
8423 if (filter->offset > offset + size)
8426 if (filter->offset + filter->size < offset)
8432 static bool perf_addr_filter_vma_adjust(struct perf_addr_filter *filter,
8433 struct vm_area_struct *vma,
8434 struct perf_addr_filter_range *fr)
8436 unsigned long vma_size = vma->vm_end - vma->vm_start;
8437 unsigned long off = vma->vm_pgoff << PAGE_SHIFT;
8438 struct file *file = vma->vm_file;
8440 if (!perf_addr_filter_match(filter, file, off, vma_size))
8443 if (filter->offset < off) {
8444 fr->start = vma->vm_start;
8445 fr->size = min(vma_size, filter->size - (off - filter->offset));
8447 fr->start = vma->vm_start + filter->offset - off;
8448 fr->size = min(vma->vm_end - fr->start, filter->size);
8454 static void __perf_addr_filters_adjust(struct perf_event *event, void *data)
8456 struct perf_addr_filters_head *ifh = perf_event_addr_filters(event);
8457 struct vm_area_struct *vma = data;
8458 struct perf_addr_filter *filter;
8459 unsigned int restart = 0, count = 0;
8460 unsigned long flags;
8462 if (!has_addr_filter(event))
8468 raw_spin_lock_irqsave(&ifh->lock, flags);
8469 list_for_each_entry(filter, &ifh->list, entry) {
8470 if (perf_addr_filter_vma_adjust(filter, vma,
8471 &event->addr_filter_ranges[count]))
8478 event->addr_filters_gen++;
8479 raw_spin_unlock_irqrestore(&ifh->lock, flags);
8482 perf_event_stop(event, 1);
8486 * Adjust all task's events' filters to the new vma
8488 static void perf_addr_filters_adjust(struct vm_area_struct *vma)
8490 struct perf_event_context *ctx;
8494 * Data tracing isn't supported yet and as such there is no need
8495 * to keep track of anything that isn't related to executable code:
8497 if (!(vma->vm_flags & VM_EXEC))
8501 for_each_task_context_nr(ctxn) {
8502 ctx = rcu_dereference(current->perf_event_ctxp[ctxn]);
8506 perf_iterate_ctx(ctx, __perf_addr_filters_adjust, vma, true);
8511 void perf_event_mmap(struct vm_area_struct *vma)
8513 struct perf_mmap_event mmap_event;
8515 if (!atomic_read(&nr_mmap_events))
8518 mmap_event = (struct perf_mmap_event){
8524 .type = PERF_RECORD_MMAP,
8525 .misc = PERF_RECORD_MISC_USER,
8530 .start = vma->vm_start,
8531 .len = vma->vm_end - vma->vm_start,
8532 .pgoff = (u64)vma->vm_pgoff << PAGE_SHIFT,
8534 /* .maj (attr_mmap2 only) */
8535 /* .min (attr_mmap2 only) */
8536 /* .ino (attr_mmap2 only) */
8537 /* .ino_generation (attr_mmap2 only) */
8538 /* .prot (attr_mmap2 only) */
8539 /* .flags (attr_mmap2 only) */
8542 perf_addr_filters_adjust(vma);
8543 perf_event_mmap_event(&mmap_event);
8546 void perf_event_aux_event(struct perf_event *event, unsigned long head,
8547 unsigned long size, u64 flags)
8549 struct perf_output_handle handle;
8550 struct perf_sample_data sample;
8551 struct perf_aux_event {
8552 struct perf_event_header header;
8558 .type = PERF_RECORD_AUX,
8560 .size = sizeof(rec),
8568 perf_event_header__init_id(&rec.header, &sample, event);
8569 ret = perf_output_begin(&handle, &sample, event, rec.header.size);
8574 perf_output_put(&handle, rec);
8575 perf_event__output_id_sample(event, &handle, &sample);
8577 perf_output_end(&handle);
8581 * Lost/dropped samples logging
8583 void perf_log_lost_samples(struct perf_event *event, u64 lost)
8585 struct perf_output_handle handle;
8586 struct perf_sample_data sample;
8590 struct perf_event_header header;
8592 } lost_samples_event = {
8594 .type = PERF_RECORD_LOST_SAMPLES,
8596 .size = sizeof(lost_samples_event),
8601 perf_event_header__init_id(&lost_samples_event.header, &sample, event);
8603 ret = perf_output_begin(&handle, &sample, event,
8604 lost_samples_event.header.size);
8608 perf_output_put(&handle, lost_samples_event);
8609 perf_event__output_id_sample(event, &handle, &sample);
8610 perf_output_end(&handle);
8614 * context_switch tracking
8617 struct perf_switch_event {
8618 struct task_struct *task;
8619 struct task_struct *next_prev;
8622 struct perf_event_header header;
8628 static int perf_event_switch_match(struct perf_event *event)
8630 return event->attr.context_switch;
8633 static void perf_event_switch_output(struct perf_event *event, void *data)
8635 struct perf_switch_event *se = data;
8636 struct perf_output_handle handle;
8637 struct perf_sample_data sample;
8640 if (!perf_event_switch_match(event))
8643 /* Only CPU-wide events are allowed to see next/prev pid/tid */
8644 if (event->ctx->task) {
8645 se->event_id.header.type = PERF_RECORD_SWITCH;
8646 se->event_id.header.size = sizeof(se->event_id.header);
8648 se->event_id.header.type = PERF_RECORD_SWITCH_CPU_WIDE;
8649 se->event_id.header.size = sizeof(se->event_id);
8650 se->event_id.next_prev_pid =
8651 perf_event_pid(event, se->next_prev);
8652 se->event_id.next_prev_tid =
8653 perf_event_tid(event, se->next_prev);
8656 perf_event_header__init_id(&se->event_id.header, &sample, event);
8658 ret = perf_output_begin(&handle, &sample, event, se->event_id.header.size);
8662 if (event->ctx->task)
8663 perf_output_put(&handle, se->event_id.header);
8665 perf_output_put(&handle, se->event_id);
8667 perf_event__output_id_sample(event, &handle, &sample);
8669 perf_output_end(&handle);
8672 static void perf_event_switch(struct task_struct *task,
8673 struct task_struct *next_prev, bool sched_in)
8675 struct perf_switch_event switch_event;
8677 /* N.B. caller checks nr_switch_events != 0 */
8679 switch_event = (struct perf_switch_event){
8681 .next_prev = next_prev,
8685 .misc = sched_in ? 0 : PERF_RECORD_MISC_SWITCH_OUT,
8688 /* .next_prev_pid */
8689 /* .next_prev_tid */
8693 if (!sched_in && task->on_rq) {
8694 switch_event.event_id.header.misc |=
8695 PERF_RECORD_MISC_SWITCH_OUT_PREEMPT;
8698 perf_iterate_sb(perf_event_switch_output, &switch_event, NULL);
8702 * IRQ throttle logging
8705 static void perf_log_throttle(struct perf_event *event, int enable)
8707 struct perf_output_handle handle;
8708 struct perf_sample_data sample;
8712 struct perf_event_header header;
8716 } throttle_event = {
8718 .type = PERF_RECORD_THROTTLE,
8720 .size = sizeof(throttle_event),
8722 .time = perf_event_clock(event),
8723 .id = primary_event_id(event),
8724 .stream_id = event->id,
8728 throttle_event.header.type = PERF_RECORD_UNTHROTTLE;
8730 perf_event_header__init_id(&throttle_event.header, &sample, event);
8732 ret = perf_output_begin(&handle, &sample, event,
8733 throttle_event.header.size);
8737 perf_output_put(&handle, throttle_event);
8738 perf_event__output_id_sample(event, &handle, &sample);
8739 perf_output_end(&handle);
8743 * ksymbol register/unregister tracking
8746 struct perf_ksymbol_event {
8750 struct perf_event_header header;
8758 static int perf_event_ksymbol_match(struct perf_event *event)
8760 return event->attr.ksymbol;
8763 static void perf_event_ksymbol_output(struct perf_event *event, void *data)
8765 struct perf_ksymbol_event *ksymbol_event = data;
8766 struct perf_output_handle handle;
8767 struct perf_sample_data sample;
8770 if (!perf_event_ksymbol_match(event))
8773 perf_event_header__init_id(&ksymbol_event->event_id.header,
8775 ret = perf_output_begin(&handle, &sample, event,
8776 ksymbol_event->event_id.header.size);
8780 perf_output_put(&handle, ksymbol_event->event_id);
8781 __output_copy(&handle, ksymbol_event->name, ksymbol_event->name_len);
8782 perf_event__output_id_sample(event, &handle, &sample);
8784 perf_output_end(&handle);
8787 void perf_event_ksymbol(u16 ksym_type, u64 addr, u32 len, bool unregister,
8790 struct perf_ksymbol_event ksymbol_event;
8791 char name[KSYM_NAME_LEN];
8795 if (!atomic_read(&nr_ksymbol_events))
8798 if (ksym_type >= PERF_RECORD_KSYMBOL_TYPE_MAX ||
8799 ksym_type == PERF_RECORD_KSYMBOL_TYPE_UNKNOWN)
8802 strlcpy(name, sym, KSYM_NAME_LEN);
8803 name_len = strlen(name) + 1;
8804 while (!IS_ALIGNED(name_len, sizeof(u64)))
8805 name[name_len++] = '\0';
8806 BUILD_BUG_ON(KSYM_NAME_LEN % sizeof(u64));
8809 flags |= PERF_RECORD_KSYMBOL_FLAGS_UNREGISTER;
8811 ksymbol_event = (struct perf_ksymbol_event){
8813 .name_len = name_len,
8816 .type = PERF_RECORD_KSYMBOL,
8817 .size = sizeof(ksymbol_event.event_id) +
8822 .ksym_type = ksym_type,
8827 perf_iterate_sb(perf_event_ksymbol_output, &ksymbol_event, NULL);
8830 WARN_ONCE(1, "%s: Invalid KSYMBOL type 0x%x\n", __func__, ksym_type);
8834 * bpf program load/unload tracking
8837 struct perf_bpf_event {
8838 struct bpf_prog *prog;
8840 struct perf_event_header header;
8844 u8 tag[BPF_TAG_SIZE];
8848 static int perf_event_bpf_match(struct perf_event *event)
8850 return event->attr.bpf_event;
8853 static void perf_event_bpf_output(struct perf_event *event, void *data)
8855 struct perf_bpf_event *bpf_event = data;
8856 struct perf_output_handle handle;
8857 struct perf_sample_data sample;
8860 if (!perf_event_bpf_match(event))
8863 perf_event_header__init_id(&bpf_event->event_id.header,
8865 ret = perf_output_begin(&handle, data, event,
8866 bpf_event->event_id.header.size);
8870 perf_output_put(&handle, bpf_event->event_id);
8871 perf_event__output_id_sample(event, &handle, &sample);
8873 perf_output_end(&handle);
8876 static void perf_event_bpf_emit_ksymbols(struct bpf_prog *prog,
8877 enum perf_bpf_event_type type)
8879 bool unregister = type == PERF_BPF_EVENT_PROG_UNLOAD;
8882 if (prog->aux->func_cnt == 0) {
8883 perf_event_ksymbol(PERF_RECORD_KSYMBOL_TYPE_BPF,
8884 (u64)(unsigned long)prog->bpf_func,
8885 prog->jited_len, unregister,
8886 prog->aux->ksym.name);
8888 for (i = 0; i < prog->aux->func_cnt; i++) {
8889 struct bpf_prog *subprog = prog->aux->func[i];
8892 PERF_RECORD_KSYMBOL_TYPE_BPF,
8893 (u64)(unsigned long)subprog->bpf_func,
8894 subprog->jited_len, unregister,
8895 prog->aux->ksym.name);
8900 void perf_event_bpf_event(struct bpf_prog *prog,
8901 enum perf_bpf_event_type type,
8904 struct perf_bpf_event bpf_event;
8906 if (type <= PERF_BPF_EVENT_UNKNOWN ||
8907 type >= PERF_BPF_EVENT_MAX)
8911 case PERF_BPF_EVENT_PROG_LOAD:
8912 case PERF_BPF_EVENT_PROG_UNLOAD:
8913 if (atomic_read(&nr_ksymbol_events))
8914 perf_event_bpf_emit_ksymbols(prog, type);
8920 if (!atomic_read(&nr_bpf_events))
8923 bpf_event = (struct perf_bpf_event){
8927 .type = PERF_RECORD_BPF_EVENT,
8928 .size = sizeof(bpf_event.event_id),
8932 .id = prog->aux->id,
8936 BUILD_BUG_ON(BPF_TAG_SIZE % sizeof(u64));
8938 memcpy(bpf_event.event_id.tag, prog->tag, BPF_TAG_SIZE);
8939 perf_iterate_sb(perf_event_bpf_output, &bpf_event, NULL);
8942 struct perf_text_poke_event {
8943 const void *old_bytes;
8944 const void *new_bytes;
8950 struct perf_event_header header;
8956 static int perf_event_text_poke_match(struct perf_event *event)
8958 return event->attr.text_poke;
8961 static void perf_event_text_poke_output(struct perf_event *event, void *data)
8963 struct perf_text_poke_event *text_poke_event = data;
8964 struct perf_output_handle handle;
8965 struct perf_sample_data sample;
8969 if (!perf_event_text_poke_match(event))
8972 perf_event_header__init_id(&text_poke_event->event_id.header, &sample, event);
8974 ret = perf_output_begin(&handle, &sample, event,
8975 text_poke_event->event_id.header.size);
8979 perf_output_put(&handle, text_poke_event->event_id);
8980 perf_output_put(&handle, text_poke_event->old_len);
8981 perf_output_put(&handle, text_poke_event->new_len);
8983 __output_copy(&handle, text_poke_event->old_bytes, text_poke_event->old_len);
8984 __output_copy(&handle, text_poke_event->new_bytes, text_poke_event->new_len);
8986 if (text_poke_event->pad)
8987 __output_copy(&handle, &padding, text_poke_event->pad);
8989 perf_event__output_id_sample(event, &handle, &sample);
8991 perf_output_end(&handle);
8994 void perf_event_text_poke(const void *addr, const void *old_bytes,
8995 size_t old_len, const void *new_bytes, size_t new_len)
8997 struct perf_text_poke_event text_poke_event;
9000 if (!atomic_read(&nr_text_poke_events))
9003 tot = sizeof(text_poke_event.old_len) + old_len;
9004 tot += sizeof(text_poke_event.new_len) + new_len;
9005 pad = ALIGN(tot, sizeof(u64)) - tot;
9007 text_poke_event = (struct perf_text_poke_event){
9008 .old_bytes = old_bytes,
9009 .new_bytes = new_bytes,
9015 .type = PERF_RECORD_TEXT_POKE,
9016 .misc = PERF_RECORD_MISC_KERNEL,
9017 .size = sizeof(text_poke_event.event_id) + tot + pad,
9019 .addr = (unsigned long)addr,
9023 perf_iterate_sb(perf_event_text_poke_output, &text_poke_event, NULL);
9026 void perf_event_itrace_started(struct perf_event *event)
9028 event->attach_state |= PERF_ATTACH_ITRACE;
9031 static void perf_log_itrace_start(struct perf_event *event)
9033 struct perf_output_handle handle;
9034 struct perf_sample_data sample;
9035 struct perf_aux_event {
9036 struct perf_event_header header;
9043 event = event->parent;
9045 if (!(event->pmu->capabilities & PERF_PMU_CAP_ITRACE) ||
9046 event->attach_state & PERF_ATTACH_ITRACE)
9049 rec.header.type = PERF_RECORD_ITRACE_START;
9050 rec.header.misc = 0;
9051 rec.header.size = sizeof(rec);
9052 rec.pid = perf_event_pid(event, current);
9053 rec.tid = perf_event_tid(event, current);
9055 perf_event_header__init_id(&rec.header, &sample, event);
9056 ret = perf_output_begin(&handle, &sample, event, rec.header.size);
9061 perf_output_put(&handle, rec);
9062 perf_event__output_id_sample(event, &handle, &sample);
9064 perf_output_end(&handle);
9068 __perf_event_account_interrupt(struct perf_event *event, int throttle)
9070 struct hw_perf_event *hwc = &event->hw;
9074 seq = __this_cpu_read(perf_throttled_seq);
9075 if (seq != hwc->interrupts_seq) {
9076 hwc->interrupts_seq = seq;
9077 hwc->interrupts = 1;
9080 if (unlikely(throttle
9081 && hwc->interrupts >= max_samples_per_tick)) {
9082 __this_cpu_inc(perf_throttled_count);
9083 tick_dep_set_cpu(smp_processor_id(), TICK_DEP_BIT_PERF_EVENTS);
9084 hwc->interrupts = MAX_INTERRUPTS;
9085 perf_log_throttle(event, 0);
9090 if (event->attr.freq) {
9091 u64 now = perf_clock();
9092 s64 delta = now - hwc->freq_time_stamp;
9094 hwc->freq_time_stamp = now;
9096 if (delta > 0 && delta < 2*TICK_NSEC)
9097 perf_adjust_period(event, delta, hwc->last_period, true);
9103 int perf_event_account_interrupt(struct perf_event *event)
9105 return __perf_event_account_interrupt(event, 1);
9109 * Generic event overflow handling, sampling.
9112 static int __perf_event_overflow(struct perf_event *event,
9113 int throttle, struct perf_sample_data *data,
9114 struct pt_regs *regs)
9116 int events = atomic_read(&event->event_limit);
9120 * Non-sampling counters might still use the PMI to fold short
9121 * hardware counters, ignore those.
9123 if (unlikely(!is_sampling_event(event)))
9126 ret = __perf_event_account_interrupt(event, throttle);
9129 * XXX event_limit might not quite work as expected on inherited
9133 event->pending_kill = POLL_IN;
9134 if (events && atomic_dec_and_test(&event->event_limit)) {
9136 event->pending_kill = POLL_HUP;
9137 event->pending_addr = data->addr;
9139 perf_event_disable_inatomic(event);
9142 READ_ONCE(event->overflow_handler)(event, data, regs);
9144 if (*perf_event_fasync(event) && event->pending_kill) {
9145 event->pending_wakeup = 1;
9146 irq_work_queue(&event->pending);
9152 int perf_event_overflow(struct perf_event *event,
9153 struct perf_sample_data *data,
9154 struct pt_regs *regs)
9156 return __perf_event_overflow(event, 1, data, regs);
9160 * Generic software event infrastructure
9163 struct swevent_htable {
9164 struct swevent_hlist *swevent_hlist;
9165 struct mutex hlist_mutex;
9168 /* Recursion avoidance in each contexts */
9169 int recursion[PERF_NR_CONTEXTS];
9172 static DEFINE_PER_CPU(struct swevent_htable, swevent_htable);
9175 * We directly increment event->count and keep a second value in
9176 * event->hw.period_left to count intervals. This period event
9177 * is kept in the range [-sample_period, 0] so that we can use the
9181 u64 perf_swevent_set_period(struct perf_event *event)
9183 struct hw_perf_event *hwc = &event->hw;
9184 u64 period = hwc->last_period;
9188 hwc->last_period = hwc->sample_period;
9191 old = val = local64_read(&hwc->period_left);
9195 nr = div64_u64(period + val, period);
9196 offset = nr * period;
9198 if (local64_cmpxchg(&hwc->period_left, old, val) != old)
9204 static void perf_swevent_overflow(struct perf_event *event, u64 overflow,
9205 struct perf_sample_data *data,
9206 struct pt_regs *regs)
9208 struct hw_perf_event *hwc = &event->hw;
9212 overflow = perf_swevent_set_period(event);
9214 if (hwc->interrupts == MAX_INTERRUPTS)
9217 for (; overflow; overflow--) {
9218 if (__perf_event_overflow(event, throttle,
9221 * We inhibit the overflow from happening when
9222 * hwc->interrupts == MAX_INTERRUPTS.
9230 static void perf_swevent_event(struct perf_event *event, u64 nr,
9231 struct perf_sample_data *data,
9232 struct pt_regs *regs)
9234 struct hw_perf_event *hwc = &event->hw;
9236 local64_add(nr, &event->count);
9241 if (!is_sampling_event(event))
9244 if ((event->attr.sample_type & PERF_SAMPLE_PERIOD) && !event->attr.freq) {
9246 return perf_swevent_overflow(event, 1, data, regs);
9248 data->period = event->hw.last_period;
9250 if (nr == 1 && hwc->sample_period == 1 && !event->attr.freq)
9251 return perf_swevent_overflow(event, 1, data, regs);
9253 if (local64_add_negative(nr, &hwc->period_left))
9256 perf_swevent_overflow(event, 0, data, regs);
9259 static int perf_exclude_event(struct perf_event *event,
9260 struct pt_regs *regs)
9262 if (event->hw.state & PERF_HES_STOPPED)
9266 if (event->attr.exclude_user && user_mode(regs))
9269 if (event->attr.exclude_kernel && !user_mode(regs))
9276 static int perf_swevent_match(struct perf_event *event,
9277 enum perf_type_id type,
9279 struct perf_sample_data *data,
9280 struct pt_regs *regs)
9282 if (event->attr.type != type)
9285 if (event->attr.config != event_id)
9288 if (perf_exclude_event(event, regs))
9294 static inline u64 swevent_hash(u64 type, u32 event_id)
9296 u64 val = event_id | (type << 32);
9298 return hash_64(val, SWEVENT_HLIST_BITS);
9301 static inline struct hlist_head *
9302 __find_swevent_head(struct swevent_hlist *hlist, u64 type, u32 event_id)
9304 u64 hash = swevent_hash(type, event_id);
9306 return &hlist->heads[hash];
9309 /* For the read side: events when they trigger */
9310 static inline struct hlist_head *
9311 find_swevent_head_rcu(struct swevent_htable *swhash, u64 type, u32 event_id)
9313 struct swevent_hlist *hlist;
9315 hlist = rcu_dereference(swhash->swevent_hlist);
9319 return __find_swevent_head(hlist, type, event_id);
9322 /* For the event head insertion and removal in the hlist */
9323 static inline struct hlist_head *
9324 find_swevent_head(struct swevent_htable *swhash, struct perf_event *event)
9326 struct swevent_hlist *hlist;
9327 u32 event_id = event->attr.config;
9328 u64 type = event->attr.type;
9331 * Event scheduling is always serialized against hlist allocation
9332 * and release. Which makes the protected version suitable here.
9333 * The context lock guarantees that.
9335 hlist = rcu_dereference_protected(swhash->swevent_hlist,
9336 lockdep_is_held(&event->ctx->lock));
9340 return __find_swevent_head(hlist, type, event_id);
9343 static void do_perf_sw_event(enum perf_type_id type, u32 event_id,
9345 struct perf_sample_data *data,
9346 struct pt_regs *regs)
9348 struct swevent_htable *swhash = this_cpu_ptr(&swevent_htable);
9349 struct perf_event *event;
9350 struct hlist_head *head;
9353 head = find_swevent_head_rcu(swhash, type, event_id);
9357 hlist_for_each_entry_rcu(event, head, hlist_entry) {
9358 if (perf_swevent_match(event, type, event_id, data, regs))
9359 perf_swevent_event(event, nr, data, regs);
9365 DEFINE_PER_CPU(struct pt_regs, __perf_regs[4]);
9367 int perf_swevent_get_recursion_context(void)
9369 struct swevent_htable *swhash = this_cpu_ptr(&swevent_htable);
9371 return get_recursion_context(swhash->recursion);
9373 EXPORT_SYMBOL_GPL(perf_swevent_get_recursion_context);
9375 void perf_swevent_put_recursion_context(int rctx)
9377 struct swevent_htable *swhash = this_cpu_ptr(&swevent_htable);
9379 put_recursion_context(swhash->recursion, rctx);
9382 void ___perf_sw_event(u32 event_id, u64 nr, struct pt_regs *regs, u64 addr)
9384 struct perf_sample_data data;
9386 if (WARN_ON_ONCE(!regs))
9389 perf_sample_data_init(&data, addr, 0);
9390 do_perf_sw_event(PERF_TYPE_SOFTWARE, event_id, nr, &data, regs);
9393 void __perf_sw_event(u32 event_id, u64 nr, struct pt_regs *regs, u64 addr)
9397 preempt_disable_notrace();
9398 rctx = perf_swevent_get_recursion_context();
9399 if (unlikely(rctx < 0))
9402 ___perf_sw_event(event_id, nr, regs, addr);
9404 perf_swevent_put_recursion_context(rctx);
9406 preempt_enable_notrace();
9409 static void perf_swevent_read(struct perf_event *event)
9413 static int perf_swevent_add(struct perf_event *event, int flags)
9415 struct swevent_htable *swhash = this_cpu_ptr(&swevent_htable);
9416 struct hw_perf_event *hwc = &event->hw;
9417 struct hlist_head *head;
9419 if (is_sampling_event(event)) {
9420 hwc->last_period = hwc->sample_period;
9421 perf_swevent_set_period(event);
9424 hwc->state = !(flags & PERF_EF_START);
9426 head = find_swevent_head(swhash, event);
9427 if (WARN_ON_ONCE(!head))
9430 hlist_add_head_rcu(&event->hlist_entry, head);
9431 perf_event_update_userpage(event);
9436 static void perf_swevent_del(struct perf_event *event, int flags)
9438 hlist_del_rcu(&event->hlist_entry);
9441 static void perf_swevent_start(struct perf_event *event, int flags)
9443 event->hw.state = 0;
9446 static void perf_swevent_stop(struct perf_event *event, int flags)
9448 event->hw.state = PERF_HES_STOPPED;
9451 /* Deref the hlist from the update side */
9452 static inline struct swevent_hlist *
9453 swevent_hlist_deref(struct swevent_htable *swhash)
9455 return rcu_dereference_protected(swhash->swevent_hlist,
9456 lockdep_is_held(&swhash->hlist_mutex));
9459 static void swevent_hlist_release(struct swevent_htable *swhash)
9461 struct swevent_hlist *hlist = swevent_hlist_deref(swhash);
9466 RCU_INIT_POINTER(swhash->swevent_hlist, NULL);
9467 kfree_rcu(hlist, rcu_head);
9470 static void swevent_hlist_put_cpu(int cpu)
9472 struct swevent_htable *swhash = &per_cpu(swevent_htable, cpu);
9474 mutex_lock(&swhash->hlist_mutex);
9476 if (!--swhash->hlist_refcount)
9477 swevent_hlist_release(swhash);
9479 mutex_unlock(&swhash->hlist_mutex);
9482 static void swevent_hlist_put(void)
9486 for_each_possible_cpu(cpu)
9487 swevent_hlist_put_cpu(cpu);
9490 static int swevent_hlist_get_cpu(int cpu)
9492 struct swevent_htable *swhash = &per_cpu(swevent_htable, cpu);
9495 mutex_lock(&swhash->hlist_mutex);
9496 if (!swevent_hlist_deref(swhash) &&
9497 cpumask_test_cpu(cpu, perf_online_mask)) {
9498 struct swevent_hlist *hlist;
9500 hlist = kzalloc(sizeof(*hlist), GFP_KERNEL);
9505 rcu_assign_pointer(swhash->swevent_hlist, hlist);
9507 swhash->hlist_refcount++;
9509 mutex_unlock(&swhash->hlist_mutex);
9514 static int swevent_hlist_get(void)
9516 int err, cpu, failed_cpu;
9518 mutex_lock(&pmus_lock);
9519 for_each_possible_cpu(cpu) {
9520 err = swevent_hlist_get_cpu(cpu);
9526 mutex_unlock(&pmus_lock);
9529 for_each_possible_cpu(cpu) {
9530 if (cpu == failed_cpu)
9532 swevent_hlist_put_cpu(cpu);
9534 mutex_unlock(&pmus_lock);
9538 struct static_key perf_swevent_enabled[PERF_COUNT_SW_MAX];
9540 static void sw_perf_event_destroy(struct perf_event *event)
9542 u64 event_id = event->attr.config;
9544 WARN_ON(event->parent);
9546 static_key_slow_dec(&perf_swevent_enabled[event_id]);
9547 swevent_hlist_put();
9550 static int perf_swevent_init(struct perf_event *event)
9552 u64 event_id = event->attr.config;
9554 if (event->attr.type != PERF_TYPE_SOFTWARE)
9558 * no branch sampling for software events
9560 if (has_branch_stack(event))
9564 case PERF_COUNT_SW_CPU_CLOCK:
9565 case PERF_COUNT_SW_TASK_CLOCK:
9572 if (event_id >= PERF_COUNT_SW_MAX)
9575 if (!event->parent) {
9578 err = swevent_hlist_get();
9582 static_key_slow_inc(&perf_swevent_enabled[event_id]);
9583 event->destroy = sw_perf_event_destroy;
9589 static struct pmu perf_swevent = {
9590 .task_ctx_nr = perf_sw_context,
9592 .capabilities = PERF_PMU_CAP_NO_NMI,
9594 .event_init = perf_swevent_init,
9595 .add = perf_swevent_add,
9596 .del = perf_swevent_del,
9597 .start = perf_swevent_start,
9598 .stop = perf_swevent_stop,
9599 .read = perf_swevent_read,
9602 #ifdef CONFIG_EVENT_TRACING
9604 static int perf_tp_filter_match(struct perf_event *event,
9605 struct perf_sample_data *data)
9607 void *record = data->raw->frag.data;
9609 /* only top level events have filters set */
9611 event = event->parent;
9613 if (likely(!event->filter) || filter_match_preds(event->filter, record))
9618 static int perf_tp_event_match(struct perf_event *event,
9619 struct perf_sample_data *data,
9620 struct pt_regs *regs)
9622 if (event->hw.state & PERF_HES_STOPPED)
9625 * If exclude_kernel, only trace user-space tracepoints (uprobes)
9627 if (event->attr.exclude_kernel && !user_mode(regs))
9630 if (!perf_tp_filter_match(event, data))
9636 void perf_trace_run_bpf_submit(void *raw_data, int size, int rctx,
9637 struct trace_event_call *call, u64 count,
9638 struct pt_regs *regs, struct hlist_head *head,
9639 struct task_struct *task)
9641 if (bpf_prog_array_valid(call)) {
9642 *(struct pt_regs **)raw_data = regs;
9643 if (!trace_call_bpf(call, raw_data) || hlist_empty(head)) {
9644 perf_swevent_put_recursion_context(rctx);
9648 perf_tp_event(call->event.type, count, raw_data, size, regs, head,
9651 EXPORT_SYMBOL_GPL(perf_trace_run_bpf_submit);
9653 void perf_tp_event(u16 event_type, u64 count, void *record, int entry_size,
9654 struct pt_regs *regs, struct hlist_head *head, int rctx,
9655 struct task_struct *task)
9657 struct perf_sample_data data;
9658 struct perf_event *event;
9660 struct perf_raw_record raw = {
9667 perf_sample_data_init(&data, 0, 0);
9670 perf_trace_buf_update(record, event_type);
9672 hlist_for_each_entry_rcu(event, head, hlist_entry) {
9673 if (perf_tp_event_match(event, &data, regs))
9674 perf_swevent_event(event, count, &data, regs);
9678 * If we got specified a target task, also iterate its context and
9679 * deliver this event there too.
9681 if (task && task != current) {
9682 struct perf_event_context *ctx;
9683 struct trace_entry *entry = record;
9686 ctx = rcu_dereference(task->perf_event_ctxp[perf_sw_context]);
9690 list_for_each_entry_rcu(event, &ctx->event_list, event_entry) {
9691 if (event->cpu != smp_processor_id())
9693 if (event->attr.type != PERF_TYPE_TRACEPOINT)
9695 if (event->attr.config != entry->type)
9697 if (perf_tp_event_match(event, &data, regs))
9698 perf_swevent_event(event, count, &data, regs);
9704 perf_swevent_put_recursion_context(rctx);
9706 EXPORT_SYMBOL_GPL(perf_tp_event);
9708 static void tp_perf_event_destroy(struct perf_event *event)
9710 perf_trace_destroy(event);
9713 static int perf_tp_event_init(struct perf_event *event)
9717 if (event->attr.type != PERF_TYPE_TRACEPOINT)
9721 * no branch sampling for tracepoint events
9723 if (has_branch_stack(event))
9726 err = perf_trace_init(event);
9730 event->destroy = tp_perf_event_destroy;
9735 static struct pmu perf_tracepoint = {
9736 .task_ctx_nr = perf_sw_context,
9738 .event_init = perf_tp_event_init,
9739 .add = perf_trace_add,
9740 .del = perf_trace_del,
9741 .start = perf_swevent_start,
9742 .stop = perf_swevent_stop,
9743 .read = perf_swevent_read,
9746 #if defined(CONFIG_KPROBE_EVENTS) || defined(CONFIG_UPROBE_EVENTS)
9748 * Flags in config, used by dynamic PMU kprobe and uprobe
9749 * The flags should match following PMU_FORMAT_ATTR().
9751 * PERF_PROBE_CONFIG_IS_RETPROBE if set, create kretprobe/uretprobe
9752 * if not set, create kprobe/uprobe
9754 * The following values specify a reference counter (or semaphore in the
9755 * terminology of tools like dtrace, systemtap, etc.) Userspace Statically
9756 * Defined Tracepoints (USDT). Currently, we use 40 bit for the offset.
9758 * PERF_UPROBE_REF_CTR_OFFSET_BITS # of bits in config as th offset
9759 * PERF_UPROBE_REF_CTR_OFFSET_SHIFT # of bits to shift left
9761 enum perf_probe_config {
9762 PERF_PROBE_CONFIG_IS_RETPROBE = 1U << 0, /* [k,u]retprobe */
9763 PERF_UPROBE_REF_CTR_OFFSET_BITS = 32,
9764 PERF_UPROBE_REF_CTR_OFFSET_SHIFT = 64 - PERF_UPROBE_REF_CTR_OFFSET_BITS,
9767 PMU_FORMAT_ATTR(retprobe, "config:0");
9770 #ifdef CONFIG_KPROBE_EVENTS
9771 static struct attribute *kprobe_attrs[] = {
9772 &format_attr_retprobe.attr,
9776 static struct attribute_group kprobe_format_group = {
9778 .attrs = kprobe_attrs,
9781 static const struct attribute_group *kprobe_attr_groups[] = {
9782 &kprobe_format_group,
9786 static int perf_kprobe_event_init(struct perf_event *event);
9787 static struct pmu perf_kprobe = {
9788 .task_ctx_nr = perf_sw_context,
9789 .event_init = perf_kprobe_event_init,
9790 .add = perf_trace_add,
9791 .del = perf_trace_del,
9792 .start = perf_swevent_start,
9793 .stop = perf_swevent_stop,
9794 .read = perf_swevent_read,
9795 .attr_groups = kprobe_attr_groups,
9798 static int perf_kprobe_event_init(struct perf_event *event)
9803 if (event->attr.type != perf_kprobe.type)
9806 if (!perfmon_capable())
9810 * no branch sampling for probe events
9812 if (has_branch_stack(event))
9815 is_retprobe = event->attr.config & PERF_PROBE_CONFIG_IS_RETPROBE;
9816 err = perf_kprobe_init(event, is_retprobe);
9820 event->destroy = perf_kprobe_destroy;
9824 #endif /* CONFIG_KPROBE_EVENTS */
9826 #ifdef CONFIG_UPROBE_EVENTS
9827 PMU_FORMAT_ATTR(ref_ctr_offset, "config:32-63");
9829 static struct attribute *uprobe_attrs[] = {
9830 &format_attr_retprobe.attr,
9831 &format_attr_ref_ctr_offset.attr,
9835 static struct attribute_group uprobe_format_group = {
9837 .attrs = uprobe_attrs,
9840 static const struct attribute_group *uprobe_attr_groups[] = {
9841 &uprobe_format_group,
9845 static int perf_uprobe_event_init(struct perf_event *event);
9846 static struct pmu perf_uprobe = {
9847 .task_ctx_nr = perf_sw_context,
9848 .event_init = perf_uprobe_event_init,
9849 .add = perf_trace_add,
9850 .del = perf_trace_del,
9851 .start = perf_swevent_start,
9852 .stop = perf_swevent_stop,
9853 .read = perf_swevent_read,
9854 .attr_groups = uprobe_attr_groups,
9857 static int perf_uprobe_event_init(struct perf_event *event)
9860 unsigned long ref_ctr_offset;
9863 if (event->attr.type != perf_uprobe.type)
9866 if (!perfmon_capable())
9870 * no branch sampling for probe events
9872 if (has_branch_stack(event))
9875 is_retprobe = event->attr.config & PERF_PROBE_CONFIG_IS_RETPROBE;
9876 ref_ctr_offset = event->attr.config >> PERF_UPROBE_REF_CTR_OFFSET_SHIFT;
9877 err = perf_uprobe_init(event, ref_ctr_offset, is_retprobe);
9881 event->destroy = perf_uprobe_destroy;
9885 #endif /* CONFIG_UPROBE_EVENTS */
9887 static inline void perf_tp_register(void)
9889 perf_pmu_register(&perf_tracepoint, "tracepoint", PERF_TYPE_TRACEPOINT);
9890 #ifdef CONFIG_KPROBE_EVENTS
9891 perf_pmu_register(&perf_kprobe, "kprobe", -1);
9893 #ifdef CONFIG_UPROBE_EVENTS
9894 perf_pmu_register(&perf_uprobe, "uprobe", -1);
9898 static void perf_event_free_filter(struct perf_event *event)
9900 ftrace_profile_free_filter(event);
9903 #ifdef CONFIG_BPF_SYSCALL
9904 static void bpf_overflow_handler(struct perf_event *event,
9905 struct perf_sample_data *data,
9906 struct pt_regs *regs)
9908 struct bpf_perf_event_data_kern ctx = {
9914 ctx.regs = perf_arch_bpf_user_pt_regs(regs);
9915 if (unlikely(__this_cpu_inc_return(bpf_prog_active) != 1))
9918 ret = BPF_PROG_RUN(event->prog, &ctx);
9921 __this_cpu_dec(bpf_prog_active);
9925 event->orig_overflow_handler(event, data, regs);
9928 static int perf_event_set_bpf_handler(struct perf_event *event, u32 prog_fd)
9930 struct bpf_prog *prog;
9932 if (event->overflow_handler_context)
9933 /* hw breakpoint or kernel counter */
9939 prog = bpf_prog_get_type(prog_fd, BPF_PROG_TYPE_PERF_EVENT);
9941 return PTR_ERR(prog);
9943 if (event->attr.precise_ip &&
9944 prog->call_get_stack &&
9945 (!(event->attr.sample_type & __PERF_SAMPLE_CALLCHAIN_EARLY) ||
9946 event->attr.exclude_callchain_kernel ||
9947 event->attr.exclude_callchain_user)) {
9949 * On perf_event with precise_ip, calling bpf_get_stack()
9950 * may trigger unwinder warnings and occasional crashes.
9951 * bpf_get_[stack|stackid] works around this issue by using
9952 * callchain attached to perf_sample_data. If the
9953 * perf_event does not full (kernel and user) callchain
9954 * attached to perf_sample_data, do not allow attaching BPF
9955 * program that calls bpf_get_[stack|stackid].
9962 event->orig_overflow_handler = READ_ONCE(event->overflow_handler);
9963 WRITE_ONCE(event->overflow_handler, bpf_overflow_handler);
9967 static void perf_event_free_bpf_handler(struct perf_event *event)
9969 struct bpf_prog *prog = event->prog;
9974 WRITE_ONCE(event->overflow_handler, event->orig_overflow_handler);
9979 static int perf_event_set_bpf_handler(struct perf_event *event, u32 prog_fd)
9983 static void perf_event_free_bpf_handler(struct perf_event *event)
9989 * returns true if the event is a tracepoint, or a kprobe/upprobe created
9990 * with perf_event_open()
9992 static inline bool perf_event_is_tracing(struct perf_event *event)
9994 if (event->pmu == &perf_tracepoint)
9996 #ifdef CONFIG_KPROBE_EVENTS
9997 if (event->pmu == &perf_kprobe)
10000 #ifdef CONFIG_UPROBE_EVENTS
10001 if (event->pmu == &perf_uprobe)
10007 static int perf_event_set_bpf_prog(struct perf_event *event, u32 prog_fd)
10009 bool is_kprobe, is_tracepoint, is_syscall_tp;
10010 struct bpf_prog *prog;
10013 if (!perf_event_is_tracing(event))
10014 return perf_event_set_bpf_handler(event, prog_fd);
10016 is_kprobe = event->tp_event->flags & TRACE_EVENT_FL_UKPROBE;
10017 is_tracepoint = event->tp_event->flags & TRACE_EVENT_FL_TRACEPOINT;
10018 is_syscall_tp = is_syscall_trace_event(event->tp_event);
10019 if (!is_kprobe && !is_tracepoint && !is_syscall_tp)
10020 /* bpf programs can only be attached to u/kprobe or tracepoint */
10023 prog = bpf_prog_get(prog_fd);
10025 return PTR_ERR(prog);
10027 if ((is_kprobe && prog->type != BPF_PROG_TYPE_KPROBE) ||
10028 (is_tracepoint && prog->type != BPF_PROG_TYPE_TRACEPOINT) ||
10029 (is_syscall_tp && prog->type != BPF_PROG_TYPE_TRACEPOINT)) {
10030 /* valid fd, but invalid bpf program type */
10031 bpf_prog_put(prog);
10035 /* Kprobe override only works for kprobes, not uprobes. */
10036 if (prog->kprobe_override &&
10037 !(event->tp_event->flags & TRACE_EVENT_FL_KPROBE)) {
10038 bpf_prog_put(prog);
10042 if (is_tracepoint || is_syscall_tp) {
10043 int off = trace_event_get_offsets(event->tp_event);
10045 if (prog->aux->max_ctx_offset > off) {
10046 bpf_prog_put(prog);
10051 ret = perf_event_attach_bpf_prog(event, prog);
10053 bpf_prog_put(prog);
10057 static void perf_event_free_bpf_prog(struct perf_event *event)
10059 if (!perf_event_is_tracing(event)) {
10060 perf_event_free_bpf_handler(event);
10063 perf_event_detach_bpf_prog(event);
10068 static inline void perf_tp_register(void)
10072 static void perf_event_free_filter(struct perf_event *event)
10076 static int perf_event_set_bpf_prog(struct perf_event *event, u32 prog_fd)
10081 static void perf_event_free_bpf_prog(struct perf_event *event)
10084 #endif /* CONFIG_EVENT_TRACING */
10086 #ifdef CONFIG_HAVE_HW_BREAKPOINT
10087 void perf_bp_event(struct perf_event *bp, void *data)
10089 struct perf_sample_data sample;
10090 struct pt_regs *regs = data;
10092 perf_sample_data_init(&sample, bp->attr.bp_addr, 0);
10094 if (!bp->hw.state && !perf_exclude_event(bp, regs))
10095 perf_swevent_event(bp, 1, &sample, regs);
10100 * Allocate a new address filter
10102 static struct perf_addr_filter *
10103 perf_addr_filter_new(struct perf_event *event, struct list_head *filters)
10105 int node = cpu_to_node(event->cpu == -1 ? 0 : event->cpu);
10106 struct perf_addr_filter *filter;
10108 filter = kzalloc_node(sizeof(*filter), GFP_KERNEL, node);
10112 INIT_LIST_HEAD(&filter->entry);
10113 list_add_tail(&filter->entry, filters);
10118 static void free_filters_list(struct list_head *filters)
10120 struct perf_addr_filter *filter, *iter;
10122 list_for_each_entry_safe(filter, iter, filters, entry) {
10123 path_put(&filter->path);
10124 list_del(&filter->entry);
10130 * Free existing address filters and optionally install new ones
10132 static void perf_addr_filters_splice(struct perf_event *event,
10133 struct list_head *head)
10135 unsigned long flags;
10138 if (!has_addr_filter(event))
10141 /* don't bother with children, they don't have their own filters */
10145 raw_spin_lock_irqsave(&event->addr_filters.lock, flags);
10147 list_splice_init(&event->addr_filters.list, &list);
10149 list_splice(head, &event->addr_filters.list);
10151 raw_spin_unlock_irqrestore(&event->addr_filters.lock, flags);
10153 free_filters_list(&list);
10157 * Scan through mm's vmas and see if one of them matches the
10158 * @filter; if so, adjust filter's address range.
10159 * Called with mm::mmap_lock down for reading.
10161 static void perf_addr_filter_apply(struct perf_addr_filter *filter,
10162 struct mm_struct *mm,
10163 struct perf_addr_filter_range *fr)
10165 struct vm_area_struct *vma;
10167 for (vma = mm->mmap; vma; vma = vma->vm_next) {
10171 if (perf_addr_filter_vma_adjust(filter, vma, fr))
10177 * Update event's address range filters based on the
10178 * task's existing mappings, if any.
10180 static void perf_event_addr_filters_apply(struct perf_event *event)
10182 struct perf_addr_filters_head *ifh = perf_event_addr_filters(event);
10183 struct task_struct *task = READ_ONCE(event->ctx->task);
10184 struct perf_addr_filter *filter;
10185 struct mm_struct *mm = NULL;
10186 unsigned int count = 0;
10187 unsigned long flags;
10190 * We may observe TASK_TOMBSTONE, which means that the event tear-down
10191 * will stop on the parent's child_mutex that our caller is also holding
10193 if (task == TASK_TOMBSTONE)
10196 if (ifh->nr_file_filters) {
10197 mm = get_task_mm(event->ctx->task);
10201 mmap_read_lock(mm);
10204 raw_spin_lock_irqsave(&ifh->lock, flags);
10205 list_for_each_entry(filter, &ifh->list, entry) {
10206 if (filter->path.dentry) {
10208 * Adjust base offset if the filter is associated to a
10209 * binary that needs to be mapped:
10211 event->addr_filter_ranges[count].start = 0;
10212 event->addr_filter_ranges[count].size = 0;
10214 perf_addr_filter_apply(filter, mm, &event->addr_filter_ranges[count]);
10216 event->addr_filter_ranges[count].start = filter->offset;
10217 event->addr_filter_ranges[count].size = filter->size;
10223 event->addr_filters_gen++;
10224 raw_spin_unlock_irqrestore(&ifh->lock, flags);
10226 if (ifh->nr_file_filters) {
10227 mmap_read_unlock(mm);
10233 perf_event_stop(event, 1);
10237 * Address range filtering: limiting the data to certain
10238 * instruction address ranges. Filters are ioctl()ed to us from
10239 * userspace as ascii strings.
10241 * Filter string format:
10243 * ACTION RANGE_SPEC
10244 * where ACTION is one of the
10245 * * "filter": limit the trace to this region
10246 * * "start": start tracing from this address
10247 * * "stop": stop tracing at this address/region;
10249 * * for kernel addresses: <start address>[/<size>]
10250 * * for object files: <start address>[/<size>]@</path/to/object/file>
10252 * if <size> is not specified or is zero, the range is treated as a single
10253 * address; not valid for ACTION=="filter".
10267 IF_STATE_ACTION = 0,
10272 static const match_table_t if_tokens = {
10273 { IF_ACT_FILTER, "filter" },
10274 { IF_ACT_START, "start" },
10275 { IF_ACT_STOP, "stop" },
10276 { IF_SRC_FILE, "%u/%u@%s" },
10277 { IF_SRC_KERNEL, "%u/%u" },
10278 { IF_SRC_FILEADDR, "%u@%s" },
10279 { IF_SRC_KERNELADDR, "%u" },
10280 { IF_ACT_NONE, NULL },
10284 * Address filter string parser
10287 perf_event_parse_addr_filter(struct perf_event *event, char *fstr,
10288 struct list_head *filters)
10290 struct perf_addr_filter *filter = NULL;
10291 char *start, *orig, *filename = NULL;
10292 substring_t args[MAX_OPT_ARGS];
10293 int state = IF_STATE_ACTION, token;
10294 unsigned int kernel = 0;
10297 orig = fstr = kstrdup(fstr, GFP_KERNEL);
10301 while ((start = strsep(&fstr, " ,\n")) != NULL) {
10302 static const enum perf_addr_filter_action_t actions[] = {
10303 [IF_ACT_FILTER] = PERF_ADDR_FILTER_ACTION_FILTER,
10304 [IF_ACT_START] = PERF_ADDR_FILTER_ACTION_START,
10305 [IF_ACT_STOP] = PERF_ADDR_FILTER_ACTION_STOP,
10312 /* filter definition begins */
10313 if (state == IF_STATE_ACTION) {
10314 filter = perf_addr_filter_new(event, filters);
10319 token = match_token(start, if_tokens, args);
10321 case IF_ACT_FILTER:
10324 if (state != IF_STATE_ACTION)
10327 filter->action = actions[token];
10328 state = IF_STATE_SOURCE;
10331 case IF_SRC_KERNELADDR:
10332 case IF_SRC_KERNEL:
10336 case IF_SRC_FILEADDR:
10338 if (state != IF_STATE_SOURCE)
10342 ret = kstrtoul(args[0].from, 0, &filter->offset);
10346 if (token == IF_SRC_KERNEL || token == IF_SRC_FILE) {
10348 ret = kstrtoul(args[1].from, 0, &filter->size);
10353 if (token == IF_SRC_FILE || token == IF_SRC_FILEADDR) {
10354 int fpos = token == IF_SRC_FILE ? 2 : 1;
10357 filename = match_strdup(&args[fpos]);
10364 state = IF_STATE_END;
10372 * Filter definition is fully parsed, validate and install it.
10373 * Make sure that it doesn't contradict itself or the event's
10376 if (state == IF_STATE_END) {
10378 if (kernel && event->attr.exclude_kernel)
10382 * ACTION "filter" must have a non-zero length region
10385 if (filter->action == PERF_ADDR_FILTER_ACTION_FILTER &&
10394 * For now, we only support file-based filters
10395 * in per-task events; doing so for CPU-wide
10396 * events requires additional context switching
10397 * trickery, since same object code will be
10398 * mapped at different virtual addresses in
10399 * different processes.
10402 if (!event->ctx->task)
10405 /* look up the path and grab its inode */
10406 ret = kern_path(filename, LOOKUP_FOLLOW,
10412 if (!filter->path.dentry ||
10413 !S_ISREG(d_inode(filter->path.dentry)
10417 event->addr_filters.nr_file_filters++;
10420 /* ready to consume more filters */
10421 state = IF_STATE_ACTION;
10426 if (state != IF_STATE_ACTION)
10436 free_filters_list(filters);
10443 perf_event_set_addr_filter(struct perf_event *event, char *filter_str)
10445 LIST_HEAD(filters);
10449 * Since this is called in perf_ioctl() path, we're already holding
10452 lockdep_assert_held(&event->ctx->mutex);
10454 if (WARN_ON_ONCE(event->parent))
10457 ret = perf_event_parse_addr_filter(event, filter_str, &filters);
10459 goto fail_clear_files;
10461 ret = event->pmu->addr_filters_validate(&filters);
10463 goto fail_free_filters;
10465 /* remove existing filters, if any */
10466 perf_addr_filters_splice(event, &filters);
10468 /* install new filters */
10469 perf_event_for_each_child(event, perf_event_addr_filters_apply);
10474 free_filters_list(&filters);
10477 event->addr_filters.nr_file_filters = 0;
10482 static int perf_event_set_filter(struct perf_event *event, void __user *arg)
10487 filter_str = strndup_user(arg, PAGE_SIZE);
10488 if (IS_ERR(filter_str))
10489 return PTR_ERR(filter_str);
10491 #ifdef CONFIG_EVENT_TRACING
10492 if (perf_event_is_tracing(event)) {
10493 struct perf_event_context *ctx = event->ctx;
10496 * Beware, here be dragons!!
10498 * the tracepoint muck will deadlock against ctx->mutex, but
10499 * the tracepoint stuff does not actually need it. So
10500 * temporarily drop ctx->mutex. As per perf_event_ctx_lock() we
10501 * already have a reference on ctx.
10503 * This can result in event getting moved to a different ctx,
10504 * but that does not affect the tracepoint state.
10506 mutex_unlock(&ctx->mutex);
10507 ret = ftrace_profile_set_filter(event, event->attr.config, filter_str);
10508 mutex_lock(&ctx->mutex);
10511 if (has_addr_filter(event))
10512 ret = perf_event_set_addr_filter(event, filter_str);
10519 * hrtimer based swevent callback
10522 static enum hrtimer_restart perf_swevent_hrtimer(struct hrtimer *hrtimer)
10524 enum hrtimer_restart ret = HRTIMER_RESTART;
10525 struct perf_sample_data data;
10526 struct pt_regs *regs;
10527 struct perf_event *event;
10530 event = container_of(hrtimer, struct perf_event, hw.hrtimer);
10532 if (event->state != PERF_EVENT_STATE_ACTIVE)
10533 return HRTIMER_NORESTART;
10535 event->pmu->read(event);
10537 perf_sample_data_init(&data, 0, event->hw.last_period);
10538 regs = get_irq_regs();
10540 if (regs && !perf_exclude_event(event, regs)) {
10541 if (!(event->attr.exclude_idle && is_idle_task(current)))
10542 if (__perf_event_overflow(event, 1, &data, regs))
10543 ret = HRTIMER_NORESTART;
10546 period = max_t(u64, 10000, event->hw.sample_period);
10547 hrtimer_forward_now(hrtimer, ns_to_ktime(period));
10552 static void perf_swevent_start_hrtimer(struct perf_event *event)
10554 struct hw_perf_event *hwc = &event->hw;
10557 if (!is_sampling_event(event))
10560 period = local64_read(&hwc->period_left);
10565 local64_set(&hwc->period_left, 0);
10567 period = max_t(u64, 10000, hwc->sample_period);
10569 hrtimer_start(&hwc->hrtimer, ns_to_ktime(period),
10570 HRTIMER_MODE_REL_PINNED_HARD);
10573 static void perf_swevent_cancel_hrtimer(struct perf_event *event)
10575 struct hw_perf_event *hwc = &event->hw;
10577 if (is_sampling_event(event)) {
10578 ktime_t remaining = hrtimer_get_remaining(&hwc->hrtimer);
10579 local64_set(&hwc->period_left, ktime_to_ns(remaining));
10581 hrtimer_cancel(&hwc->hrtimer);
10585 static void perf_swevent_init_hrtimer(struct perf_event *event)
10587 struct hw_perf_event *hwc = &event->hw;
10589 if (!is_sampling_event(event))
10592 hrtimer_init(&hwc->hrtimer, CLOCK_MONOTONIC, HRTIMER_MODE_REL_HARD);
10593 hwc->hrtimer.function = perf_swevent_hrtimer;
10596 * Since hrtimers have a fixed rate, we can do a static freq->period
10597 * mapping and avoid the whole period adjust feedback stuff.
10599 if (event->attr.freq) {
10600 long freq = event->attr.sample_freq;
10602 event->attr.sample_period = NSEC_PER_SEC / freq;
10603 hwc->sample_period = event->attr.sample_period;
10604 local64_set(&hwc->period_left, hwc->sample_period);
10605 hwc->last_period = hwc->sample_period;
10606 event->attr.freq = 0;
10611 * Software event: cpu wall time clock
10614 static void cpu_clock_event_update(struct perf_event *event)
10619 now = local_clock();
10620 prev = local64_xchg(&event->hw.prev_count, now);
10621 local64_add(now - prev, &event->count);
10624 static void cpu_clock_event_start(struct perf_event *event, int flags)
10626 local64_set(&event->hw.prev_count, local_clock());
10627 perf_swevent_start_hrtimer(event);
10630 static void cpu_clock_event_stop(struct perf_event *event, int flags)
10632 perf_swevent_cancel_hrtimer(event);
10633 cpu_clock_event_update(event);
10636 static int cpu_clock_event_add(struct perf_event *event, int flags)
10638 if (flags & PERF_EF_START)
10639 cpu_clock_event_start(event, flags);
10640 perf_event_update_userpage(event);
10645 static void cpu_clock_event_del(struct perf_event *event, int flags)
10647 cpu_clock_event_stop(event, flags);
10650 static void cpu_clock_event_read(struct perf_event *event)
10652 cpu_clock_event_update(event);
10655 static int cpu_clock_event_init(struct perf_event *event)
10657 if (event->attr.type != PERF_TYPE_SOFTWARE)
10660 if (event->attr.config != PERF_COUNT_SW_CPU_CLOCK)
10664 * no branch sampling for software events
10666 if (has_branch_stack(event))
10667 return -EOPNOTSUPP;
10669 perf_swevent_init_hrtimer(event);
10674 static struct pmu perf_cpu_clock = {
10675 .task_ctx_nr = perf_sw_context,
10677 .capabilities = PERF_PMU_CAP_NO_NMI,
10679 .event_init = cpu_clock_event_init,
10680 .add = cpu_clock_event_add,
10681 .del = cpu_clock_event_del,
10682 .start = cpu_clock_event_start,
10683 .stop = cpu_clock_event_stop,
10684 .read = cpu_clock_event_read,
10688 * Software event: task time clock
10691 static void task_clock_event_update(struct perf_event *event, u64 now)
10696 prev = local64_xchg(&event->hw.prev_count, now);
10697 delta = now - prev;
10698 local64_add(delta, &event->count);
10701 static void task_clock_event_start(struct perf_event *event, int flags)
10703 local64_set(&event->hw.prev_count, event->ctx->time);
10704 perf_swevent_start_hrtimer(event);
10707 static void task_clock_event_stop(struct perf_event *event, int flags)
10709 perf_swevent_cancel_hrtimer(event);
10710 task_clock_event_update(event, event->ctx->time);
10713 static int task_clock_event_add(struct perf_event *event, int flags)
10715 if (flags & PERF_EF_START)
10716 task_clock_event_start(event, flags);
10717 perf_event_update_userpage(event);
10722 static void task_clock_event_del(struct perf_event *event, int flags)
10724 task_clock_event_stop(event, PERF_EF_UPDATE);
10727 static void task_clock_event_read(struct perf_event *event)
10729 u64 now = perf_clock();
10730 u64 delta = now - event->ctx->timestamp;
10731 u64 time = event->ctx->time + delta;
10733 task_clock_event_update(event, time);
10736 static int task_clock_event_init(struct perf_event *event)
10738 if (event->attr.type != PERF_TYPE_SOFTWARE)
10741 if (event->attr.config != PERF_COUNT_SW_TASK_CLOCK)
10745 * no branch sampling for software events
10747 if (has_branch_stack(event))
10748 return -EOPNOTSUPP;
10750 perf_swevent_init_hrtimer(event);
10755 static struct pmu perf_task_clock = {
10756 .task_ctx_nr = perf_sw_context,
10758 .capabilities = PERF_PMU_CAP_NO_NMI,
10760 .event_init = task_clock_event_init,
10761 .add = task_clock_event_add,
10762 .del = task_clock_event_del,
10763 .start = task_clock_event_start,
10764 .stop = task_clock_event_stop,
10765 .read = task_clock_event_read,
10768 static void perf_pmu_nop_void(struct pmu *pmu)
10772 static void perf_pmu_nop_txn(struct pmu *pmu, unsigned int flags)
10776 static int perf_pmu_nop_int(struct pmu *pmu)
10781 static int perf_event_nop_int(struct perf_event *event, u64 value)
10786 static DEFINE_PER_CPU(unsigned int, nop_txn_flags);
10788 static void perf_pmu_start_txn(struct pmu *pmu, unsigned int flags)
10790 __this_cpu_write(nop_txn_flags, flags);
10792 if (flags & ~PERF_PMU_TXN_ADD)
10795 perf_pmu_disable(pmu);
10798 static int perf_pmu_commit_txn(struct pmu *pmu)
10800 unsigned int flags = __this_cpu_read(nop_txn_flags);
10802 __this_cpu_write(nop_txn_flags, 0);
10804 if (flags & ~PERF_PMU_TXN_ADD)
10807 perf_pmu_enable(pmu);
10811 static void perf_pmu_cancel_txn(struct pmu *pmu)
10813 unsigned int flags = __this_cpu_read(nop_txn_flags);
10815 __this_cpu_write(nop_txn_flags, 0);
10817 if (flags & ~PERF_PMU_TXN_ADD)
10820 perf_pmu_enable(pmu);
10823 static int perf_event_idx_default(struct perf_event *event)
10829 * Ensures all contexts with the same task_ctx_nr have the same
10830 * pmu_cpu_context too.
10832 static struct perf_cpu_context __percpu *find_pmu_context(int ctxn)
10839 list_for_each_entry(pmu, &pmus, entry) {
10840 if (pmu->task_ctx_nr == ctxn)
10841 return pmu->pmu_cpu_context;
10847 static void free_pmu_context(struct pmu *pmu)
10850 * Static contexts such as perf_sw_context have a global lifetime
10851 * and may be shared between different PMUs. Avoid freeing them
10852 * when a single PMU is going away.
10854 if (pmu->task_ctx_nr > perf_invalid_context)
10857 free_percpu(pmu->pmu_cpu_context);
10861 * Let userspace know that this PMU supports address range filtering:
10863 static ssize_t nr_addr_filters_show(struct device *dev,
10864 struct device_attribute *attr,
10867 struct pmu *pmu = dev_get_drvdata(dev);
10869 return snprintf(page, PAGE_SIZE - 1, "%d\n", pmu->nr_addr_filters);
10871 DEVICE_ATTR_RO(nr_addr_filters);
10873 static struct idr pmu_idr;
10876 type_show(struct device *dev, struct device_attribute *attr, char *page)
10878 struct pmu *pmu = dev_get_drvdata(dev);
10880 return snprintf(page, PAGE_SIZE-1, "%d\n", pmu->type);
10882 static DEVICE_ATTR_RO(type);
10885 perf_event_mux_interval_ms_show(struct device *dev,
10886 struct device_attribute *attr,
10889 struct pmu *pmu = dev_get_drvdata(dev);
10891 return snprintf(page, PAGE_SIZE-1, "%d\n", pmu->hrtimer_interval_ms);
10894 static DEFINE_MUTEX(mux_interval_mutex);
10897 perf_event_mux_interval_ms_store(struct device *dev,
10898 struct device_attribute *attr,
10899 const char *buf, size_t count)
10901 struct pmu *pmu = dev_get_drvdata(dev);
10902 int timer, cpu, ret;
10904 ret = kstrtoint(buf, 0, &timer);
10911 /* same value, noting to do */
10912 if (timer == pmu->hrtimer_interval_ms)
10915 mutex_lock(&mux_interval_mutex);
10916 pmu->hrtimer_interval_ms = timer;
10918 /* update all cpuctx for this PMU */
10920 for_each_online_cpu(cpu) {
10921 struct perf_cpu_context *cpuctx;
10922 cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
10923 cpuctx->hrtimer_interval = ns_to_ktime(NSEC_PER_MSEC * timer);
10925 cpu_function_call(cpu,
10926 (remote_function_f)perf_mux_hrtimer_restart, cpuctx);
10928 cpus_read_unlock();
10929 mutex_unlock(&mux_interval_mutex);
10933 static DEVICE_ATTR_RW(perf_event_mux_interval_ms);
10935 static struct attribute *pmu_dev_attrs[] = {
10936 &dev_attr_type.attr,
10937 &dev_attr_perf_event_mux_interval_ms.attr,
10940 ATTRIBUTE_GROUPS(pmu_dev);
10942 static int pmu_bus_running;
10943 static struct bus_type pmu_bus = {
10944 .name = "event_source",
10945 .dev_groups = pmu_dev_groups,
10948 static void pmu_dev_release(struct device *dev)
10953 static int pmu_dev_alloc(struct pmu *pmu)
10957 pmu->dev = kzalloc(sizeof(struct device), GFP_KERNEL);
10961 pmu->dev->groups = pmu->attr_groups;
10962 device_initialize(pmu->dev);
10963 ret = dev_set_name(pmu->dev, "%s", pmu->name);
10967 dev_set_drvdata(pmu->dev, pmu);
10968 pmu->dev->bus = &pmu_bus;
10969 pmu->dev->release = pmu_dev_release;
10970 ret = device_add(pmu->dev);
10974 /* For PMUs with address filters, throw in an extra attribute: */
10975 if (pmu->nr_addr_filters)
10976 ret = device_create_file(pmu->dev, &dev_attr_nr_addr_filters);
10981 if (pmu->attr_update)
10982 ret = sysfs_update_groups(&pmu->dev->kobj, pmu->attr_update);
10991 device_del(pmu->dev);
10994 put_device(pmu->dev);
10998 static struct lock_class_key cpuctx_mutex;
10999 static struct lock_class_key cpuctx_lock;
11001 int perf_pmu_register(struct pmu *pmu, const char *name, int type)
11003 int cpu, ret, max = PERF_TYPE_MAX;
11005 mutex_lock(&pmus_lock);
11007 pmu->pmu_disable_count = alloc_percpu(int);
11008 if (!pmu->pmu_disable_count)
11016 if (type != PERF_TYPE_SOFTWARE) {
11020 ret = idr_alloc(&pmu_idr, pmu, max, 0, GFP_KERNEL);
11024 WARN_ON(type >= 0 && ret != type);
11030 if (pmu_bus_running) {
11031 ret = pmu_dev_alloc(pmu);
11037 if (pmu->task_ctx_nr == perf_hw_context) {
11038 static int hw_context_taken = 0;
11041 * Other than systems with heterogeneous CPUs, it never makes
11042 * sense for two PMUs to share perf_hw_context. PMUs which are
11043 * uncore must use perf_invalid_context.
11045 if (WARN_ON_ONCE(hw_context_taken &&
11046 !(pmu->capabilities & PERF_PMU_CAP_HETEROGENEOUS_CPUS)))
11047 pmu->task_ctx_nr = perf_invalid_context;
11049 hw_context_taken = 1;
11052 pmu->pmu_cpu_context = find_pmu_context(pmu->task_ctx_nr);
11053 if (pmu->pmu_cpu_context)
11054 goto got_cpu_context;
11057 pmu->pmu_cpu_context = alloc_percpu(struct perf_cpu_context);
11058 if (!pmu->pmu_cpu_context)
11061 for_each_possible_cpu(cpu) {
11062 struct perf_cpu_context *cpuctx;
11064 cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
11065 __perf_event_init_context(&cpuctx->ctx);
11066 lockdep_set_class(&cpuctx->ctx.mutex, &cpuctx_mutex);
11067 lockdep_set_class(&cpuctx->ctx.lock, &cpuctx_lock);
11068 cpuctx->ctx.pmu = pmu;
11069 cpuctx->online = cpumask_test_cpu(cpu, perf_online_mask);
11071 __perf_mux_hrtimer_init(cpuctx, cpu);
11073 cpuctx->heap_size = ARRAY_SIZE(cpuctx->heap_default);
11074 cpuctx->heap = cpuctx->heap_default;
11078 if (!pmu->start_txn) {
11079 if (pmu->pmu_enable) {
11081 * If we have pmu_enable/pmu_disable calls, install
11082 * transaction stubs that use that to try and batch
11083 * hardware accesses.
11085 pmu->start_txn = perf_pmu_start_txn;
11086 pmu->commit_txn = perf_pmu_commit_txn;
11087 pmu->cancel_txn = perf_pmu_cancel_txn;
11089 pmu->start_txn = perf_pmu_nop_txn;
11090 pmu->commit_txn = perf_pmu_nop_int;
11091 pmu->cancel_txn = perf_pmu_nop_void;
11095 if (!pmu->pmu_enable) {
11096 pmu->pmu_enable = perf_pmu_nop_void;
11097 pmu->pmu_disable = perf_pmu_nop_void;
11100 if (!pmu->check_period)
11101 pmu->check_period = perf_event_nop_int;
11103 if (!pmu->event_idx)
11104 pmu->event_idx = perf_event_idx_default;
11107 * Ensure the TYPE_SOFTWARE PMUs are at the head of the list,
11108 * since these cannot be in the IDR. This way the linear search
11109 * is fast, provided a valid software event is provided.
11111 if (type == PERF_TYPE_SOFTWARE || !name)
11112 list_add_rcu(&pmu->entry, &pmus);
11114 list_add_tail_rcu(&pmu->entry, &pmus);
11116 atomic_set(&pmu->exclusive_cnt, 0);
11119 mutex_unlock(&pmus_lock);
11124 device_del(pmu->dev);
11125 put_device(pmu->dev);
11128 if (pmu->type != PERF_TYPE_SOFTWARE)
11129 idr_remove(&pmu_idr, pmu->type);
11132 free_percpu(pmu->pmu_disable_count);
11135 EXPORT_SYMBOL_GPL(perf_pmu_register);
11137 void perf_pmu_unregister(struct pmu *pmu)
11139 mutex_lock(&pmus_lock);
11140 list_del_rcu(&pmu->entry);
11143 * We dereference the pmu list under both SRCU and regular RCU, so
11144 * synchronize against both of those.
11146 synchronize_srcu(&pmus_srcu);
11149 free_percpu(pmu->pmu_disable_count);
11150 if (pmu->type != PERF_TYPE_SOFTWARE)
11151 idr_remove(&pmu_idr, pmu->type);
11152 if (pmu_bus_running) {
11153 if (pmu->nr_addr_filters)
11154 device_remove_file(pmu->dev, &dev_attr_nr_addr_filters);
11155 device_del(pmu->dev);
11156 put_device(pmu->dev);
11158 free_pmu_context(pmu);
11159 mutex_unlock(&pmus_lock);
11161 EXPORT_SYMBOL_GPL(perf_pmu_unregister);
11163 static inline bool has_extended_regs(struct perf_event *event)
11165 return (event->attr.sample_regs_user & PERF_REG_EXTENDED_MASK) ||
11166 (event->attr.sample_regs_intr & PERF_REG_EXTENDED_MASK);
11169 static int perf_try_init_event(struct pmu *pmu, struct perf_event *event)
11171 struct perf_event_context *ctx = NULL;
11174 if (!try_module_get(pmu->module))
11178 * A number of pmu->event_init() methods iterate the sibling_list to,
11179 * for example, validate if the group fits on the PMU. Therefore,
11180 * if this is a sibling event, acquire the ctx->mutex to protect
11181 * the sibling_list.
11183 if (event->group_leader != event && pmu->task_ctx_nr != perf_sw_context) {
11185 * This ctx->mutex can nest when we're called through
11186 * inheritance. See the perf_event_ctx_lock_nested() comment.
11188 ctx = perf_event_ctx_lock_nested(event->group_leader,
11189 SINGLE_DEPTH_NESTING);
11194 ret = pmu->event_init(event);
11197 perf_event_ctx_unlock(event->group_leader, ctx);
11200 if (!(pmu->capabilities & PERF_PMU_CAP_EXTENDED_REGS) &&
11201 has_extended_regs(event))
11204 if (pmu->capabilities & PERF_PMU_CAP_NO_EXCLUDE &&
11205 event_has_any_exclude_flag(event))
11208 if (ret && event->destroy)
11209 event->destroy(event);
11213 module_put(pmu->module);
11218 static struct pmu *perf_init_event(struct perf_event *event)
11220 bool extended_type = false;
11221 int idx, type, ret;
11224 idx = srcu_read_lock(&pmus_srcu);
11226 /* Try parent's PMU first: */
11227 if (event->parent && event->parent->pmu) {
11228 pmu = event->parent->pmu;
11229 ret = perf_try_init_event(pmu, event);
11235 * PERF_TYPE_HARDWARE and PERF_TYPE_HW_CACHE
11236 * are often aliases for PERF_TYPE_RAW.
11238 type = event->attr.type;
11239 if (type == PERF_TYPE_HARDWARE || type == PERF_TYPE_HW_CACHE) {
11240 type = event->attr.config >> PERF_PMU_TYPE_SHIFT;
11242 type = PERF_TYPE_RAW;
11244 extended_type = true;
11245 event->attr.config &= PERF_HW_EVENT_MASK;
11251 pmu = idr_find(&pmu_idr, type);
11254 if (event->attr.type != type && type != PERF_TYPE_RAW &&
11255 !(pmu->capabilities & PERF_PMU_CAP_EXTENDED_HW_TYPE))
11258 ret = perf_try_init_event(pmu, event);
11259 if (ret == -ENOENT && event->attr.type != type && !extended_type) {
11260 type = event->attr.type;
11265 pmu = ERR_PTR(ret);
11270 list_for_each_entry_rcu(pmu, &pmus, entry, lockdep_is_held(&pmus_srcu)) {
11271 ret = perf_try_init_event(pmu, event);
11275 if (ret != -ENOENT) {
11276 pmu = ERR_PTR(ret);
11281 pmu = ERR_PTR(-ENOENT);
11283 srcu_read_unlock(&pmus_srcu, idx);
11288 static void attach_sb_event(struct perf_event *event)
11290 struct pmu_event_list *pel = per_cpu_ptr(&pmu_sb_events, event->cpu);
11292 raw_spin_lock(&pel->lock);
11293 list_add_rcu(&event->sb_list, &pel->list);
11294 raw_spin_unlock(&pel->lock);
11298 * We keep a list of all !task (and therefore per-cpu) events
11299 * that need to receive side-band records.
11301 * This avoids having to scan all the various PMU per-cpu contexts
11302 * looking for them.
11304 static void account_pmu_sb_event(struct perf_event *event)
11306 if (is_sb_event(event))
11307 attach_sb_event(event);
11310 static void account_event_cpu(struct perf_event *event, int cpu)
11315 if (is_cgroup_event(event))
11316 atomic_inc(&per_cpu(perf_cgroup_events, cpu));
11319 /* Freq events need the tick to stay alive (see perf_event_task_tick). */
11320 static void account_freq_event_nohz(void)
11322 #ifdef CONFIG_NO_HZ_FULL
11323 /* Lock so we don't race with concurrent unaccount */
11324 spin_lock(&nr_freq_lock);
11325 if (atomic_inc_return(&nr_freq_events) == 1)
11326 tick_nohz_dep_set(TICK_DEP_BIT_PERF_EVENTS);
11327 spin_unlock(&nr_freq_lock);
11331 static void account_freq_event(void)
11333 if (tick_nohz_full_enabled())
11334 account_freq_event_nohz();
11336 atomic_inc(&nr_freq_events);
11340 static void account_event(struct perf_event *event)
11347 if (event->attach_state & (PERF_ATTACH_TASK | PERF_ATTACH_SCHED_CB))
11349 if (event->attr.mmap || event->attr.mmap_data)
11350 atomic_inc(&nr_mmap_events);
11351 if (event->attr.build_id)
11352 atomic_inc(&nr_build_id_events);
11353 if (event->attr.comm)
11354 atomic_inc(&nr_comm_events);
11355 if (event->attr.namespaces)
11356 atomic_inc(&nr_namespaces_events);
11357 if (event->attr.cgroup)
11358 atomic_inc(&nr_cgroup_events);
11359 if (event->attr.task)
11360 atomic_inc(&nr_task_events);
11361 if (event->attr.freq)
11362 account_freq_event();
11363 if (event->attr.context_switch) {
11364 atomic_inc(&nr_switch_events);
11367 if (has_branch_stack(event))
11369 if (is_cgroup_event(event))
11371 if (event->attr.ksymbol)
11372 atomic_inc(&nr_ksymbol_events);
11373 if (event->attr.bpf_event)
11374 atomic_inc(&nr_bpf_events);
11375 if (event->attr.text_poke)
11376 atomic_inc(&nr_text_poke_events);
11380 * We need the mutex here because static_branch_enable()
11381 * must complete *before* the perf_sched_count increment
11384 if (atomic_inc_not_zero(&perf_sched_count))
11387 mutex_lock(&perf_sched_mutex);
11388 if (!atomic_read(&perf_sched_count)) {
11389 static_branch_enable(&perf_sched_events);
11391 * Guarantee that all CPUs observe they key change and
11392 * call the perf scheduling hooks before proceeding to
11393 * install events that need them.
11398 * Now that we have waited for the sync_sched(), allow further
11399 * increments to by-pass the mutex.
11401 atomic_inc(&perf_sched_count);
11402 mutex_unlock(&perf_sched_mutex);
11406 account_event_cpu(event, event->cpu);
11408 account_pmu_sb_event(event);
11412 * Allocate and initialize an event structure
11414 static struct perf_event *
11415 perf_event_alloc(struct perf_event_attr *attr, int cpu,
11416 struct task_struct *task,
11417 struct perf_event *group_leader,
11418 struct perf_event *parent_event,
11419 perf_overflow_handler_t overflow_handler,
11420 void *context, int cgroup_fd)
11423 struct perf_event *event;
11424 struct hw_perf_event *hwc;
11425 long err = -EINVAL;
11428 if ((unsigned)cpu >= nr_cpu_ids) {
11429 if (!task || cpu != -1)
11430 return ERR_PTR(-EINVAL);
11432 if (attr->sigtrap && !task) {
11433 /* Requires a task: avoid signalling random tasks. */
11434 return ERR_PTR(-EINVAL);
11437 node = (cpu >= 0) ? cpu_to_node(cpu) : -1;
11438 event = kmem_cache_alloc_node(perf_event_cache, GFP_KERNEL | __GFP_ZERO,
11441 return ERR_PTR(-ENOMEM);
11444 * Single events are their own group leaders, with an
11445 * empty sibling list:
11448 group_leader = event;
11450 mutex_init(&event->child_mutex);
11451 INIT_LIST_HEAD(&event->child_list);
11453 INIT_LIST_HEAD(&event->event_entry);
11454 INIT_LIST_HEAD(&event->sibling_list);
11455 INIT_LIST_HEAD(&event->active_list);
11456 init_event_group(event);
11457 INIT_LIST_HEAD(&event->rb_entry);
11458 INIT_LIST_HEAD(&event->active_entry);
11459 INIT_LIST_HEAD(&event->addr_filters.list);
11460 INIT_HLIST_NODE(&event->hlist_entry);
11463 init_waitqueue_head(&event->waitq);
11464 event->pending_disable = -1;
11465 init_irq_work(&event->pending, perf_pending_event);
11467 mutex_init(&event->mmap_mutex);
11468 raw_spin_lock_init(&event->addr_filters.lock);
11470 atomic_long_set(&event->refcount, 1);
11472 event->attr = *attr;
11473 event->group_leader = group_leader;
11477 event->parent = parent_event;
11479 event->ns = get_pid_ns(task_active_pid_ns(current));
11480 event->id = atomic64_inc_return(&perf_event_id);
11482 event->state = PERF_EVENT_STATE_INACTIVE;
11484 if (event->attr.sigtrap)
11485 atomic_set(&event->event_limit, 1);
11488 event->attach_state = PERF_ATTACH_TASK;
11490 * XXX pmu::event_init needs to know what task to account to
11491 * and we cannot use the ctx information because we need the
11492 * pmu before we get a ctx.
11494 event->hw.target = get_task_struct(task);
11497 event->clock = &local_clock;
11499 event->clock = parent_event->clock;
11501 if (!overflow_handler && parent_event) {
11502 overflow_handler = parent_event->overflow_handler;
11503 context = parent_event->overflow_handler_context;
11504 #if defined(CONFIG_BPF_SYSCALL) && defined(CONFIG_EVENT_TRACING)
11505 if (overflow_handler == bpf_overflow_handler) {
11506 struct bpf_prog *prog = parent_event->prog;
11508 bpf_prog_inc(prog);
11509 event->prog = prog;
11510 event->orig_overflow_handler =
11511 parent_event->orig_overflow_handler;
11516 if (overflow_handler) {
11517 event->overflow_handler = overflow_handler;
11518 event->overflow_handler_context = context;
11519 } else if (is_write_backward(event)){
11520 event->overflow_handler = perf_event_output_backward;
11521 event->overflow_handler_context = NULL;
11523 event->overflow_handler = perf_event_output_forward;
11524 event->overflow_handler_context = NULL;
11527 perf_event__state_init(event);
11532 hwc->sample_period = attr->sample_period;
11533 if (attr->freq && attr->sample_freq)
11534 hwc->sample_period = 1;
11535 hwc->last_period = hwc->sample_period;
11537 local64_set(&hwc->period_left, hwc->sample_period);
11540 * We currently do not support PERF_SAMPLE_READ on inherited events.
11541 * See perf_output_read().
11543 if (attr->inherit && (attr->sample_type & PERF_SAMPLE_READ))
11546 if (!has_branch_stack(event))
11547 event->attr.branch_sample_type = 0;
11549 pmu = perf_init_event(event);
11551 err = PTR_ERR(pmu);
11556 * Disallow uncore-cgroup events, they don't make sense as the cgroup will
11557 * be different on other CPUs in the uncore mask.
11559 if (pmu->task_ctx_nr == perf_invalid_context && cgroup_fd != -1) {
11564 if (event->attr.aux_output &&
11565 !(pmu->capabilities & PERF_PMU_CAP_AUX_OUTPUT)) {
11570 if (cgroup_fd != -1) {
11571 err = perf_cgroup_connect(cgroup_fd, event, attr, group_leader);
11576 err = exclusive_event_init(event);
11580 if (has_addr_filter(event)) {
11581 event->addr_filter_ranges = kcalloc(pmu->nr_addr_filters,
11582 sizeof(struct perf_addr_filter_range),
11584 if (!event->addr_filter_ranges) {
11590 * Clone the parent's vma offsets: they are valid until exec()
11591 * even if the mm is not shared with the parent.
11593 if (event->parent) {
11594 struct perf_addr_filters_head *ifh = perf_event_addr_filters(event);
11596 raw_spin_lock_irq(&ifh->lock);
11597 memcpy(event->addr_filter_ranges,
11598 event->parent->addr_filter_ranges,
11599 pmu->nr_addr_filters * sizeof(struct perf_addr_filter_range));
11600 raw_spin_unlock_irq(&ifh->lock);
11603 /* force hw sync on the address filters */
11604 event->addr_filters_gen = 1;
11607 if (!event->parent) {
11608 if (event->attr.sample_type & PERF_SAMPLE_CALLCHAIN) {
11609 err = get_callchain_buffers(attr->sample_max_stack);
11611 goto err_addr_filters;
11615 err = security_perf_event_alloc(event);
11617 goto err_callchain_buffer;
11619 /* symmetric to unaccount_event() in _free_event() */
11620 account_event(event);
11624 err_callchain_buffer:
11625 if (!event->parent) {
11626 if (event->attr.sample_type & PERF_SAMPLE_CALLCHAIN)
11627 put_callchain_buffers();
11630 kfree(event->addr_filter_ranges);
11633 exclusive_event_destroy(event);
11636 if (is_cgroup_event(event))
11637 perf_detach_cgroup(event);
11638 if (event->destroy)
11639 event->destroy(event);
11640 module_put(pmu->module);
11643 put_pid_ns(event->ns);
11644 if (event->hw.target)
11645 put_task_struct(event->hw.target);
11646 kmem_cache_free(perf_event_cache, event);
11648 return ERR_PTR(err);
11651 static int perf_copy_attr(struct perf_event_attr __user *uattr,
11652 struct perf_event_attr *attr)
11657 /* Zero the full structure, so that a short copy will be nice. */
11658 memset(attr, 0, sizeof(*attr));
11660 ret = get_user(size, &uattr->size);
11664 /* ABI compatibility quirk: */
11666 size = PERF_ATTR_SIZE_VER0;
11667 if (size < PERF_ATTR_SIZE_VER0 || size > PAGE_SIZE)
11670 ret = copy_struct_from_user(attr, sizeof(*attr), uattr, size);
11679 if (attr->__reserved_1 || attr->__reserved_2 || attr->__reserved_3)
11682 if (attr->sample_type & ~(PERF_SAMPLE_MAX-1))
11685 if (attr->read_format & ~(PERF_FORMAT_MAX-1))
11688 if (attr->sample_type & PERF_SAMPLE_BRANCH_STACK) {
11689 u64 mask = attr->branch_sample_type;
11691 /* only using defined bits */
11692 if (mask & ~(PERF_SAMPLE_BRANCH_MAX-1))
11695 /* at least one branch bit must be set */
11696 if (!(mask & ~PERF_SAMPLE_BRANCH_PLM_ALL))
11699 /* propagate priv level, when not set for branch */
11700 if (!(mask & PERF_SAMPLE_BRANCH_PLM_ALL)) {
11702 /* exclude_kernel checked on syscall entry */
11703 if (!attr->exclude_kernel)
11704 mask |= PERF_SAMPLE_BRANCH_KERNEL;
11706 if (!attr->exclude_user)
11707 mask |= PERF_SAMPLE_BRANCH_USER;
11709 if (!attr->exclude_hv)
11710 mask |= PERF_SAMPLE_BRANCH_HV;
11712 * adjust user setting (for HW filter setup)
11714 attr->branch_sample_type = mask;
11716 /* privileged levels capture (kernel, hv): check permissions */
11717 if (mask & PERF_SAMPLE_BRANCH_PERM_PLM) {
11718 ret = perf_allow_kernel(attr);
11724 if (attr->sample_type & PERF_SAMPLE_REGS_USER) {
11725 ret = perf_reg_validate(attr->sample_regs_user);
11730 if (attr->sample_type & PERF_SAMPLE_STACK_USER) {
11731 if (!arch_perf_have_user_stack_dump())
11735 * We have __u32 type for the size, but so far
11736 * we can only use __u16 as maximum due to the
11737 * __u16 sample size limit.
11739 if (attr->sample_stack_user >= USHRT_MAX)
11741 else if (!IS_ALIGNED(attr->sample_stack_user, sizeof(u64)))
11745 if (!attr->sample_max_stack)
11746 attr->sample_max_stack = sysctl_perf_event_max_stack;
11748 if (attr->sample_type & PERF_SAMPLE_REGS_INTR)
11749 ret = perf_reg_validate(attr->sample_regs_intr);
11751 #ifndef CONFIG_CGROUP_PERF
11752 if (attr->sample_type & PERF_SAMPLE_CGROUP)
11755 if ((attr->sample_type & PERF_SAMPLE_WEIGHT) &&
11756 (attr->sample_type & PERF_SAMPLE_WEIGHT_STRUCT))
11759 if (!attr->inherit && attr->inherit_thread)
11762 if (attr->remove_on_exec && attr->enable_on_exec)
11765 if (attr->sigtrap && !attr->remove_on_exec)
11772 put_user(sizeof(*attr), &uattr->size);
11778 perf_event_set_output(struct perf_event *event, struct perf_event *output_event)
11780 struct perf_buffer *rb = NULL;
11786 /* don't allow circular references */
11787 if (event == output_event)
11791 * Don't allow cross-cpu buffers
11793 if (output_event->cpu != event->cpu)
11797 * If its not a per-cpu rb, it must be the same task.
11799 if (output_event->cpu == -1 && output_event->ctx != event->ctx)
11803 * Mixing clocks in the same buffer is trouble you don't need.
11805 if (output_event->clock != event->clock)
11809 * Either writing ring buffer from beginning or from end.
11810 * Mixing is not allowed.
11812 if (is_write_backward(output_event) != is_write_backward(event))
11816 * If both events generate aux data, they must be on the same PMU
11818 if (has_aux(event) && has_aux(output_event) &&
11819 event->pmu != output_event->pmu)
11823 mutex_lock(&event->mmap_mutex);
11824 /* Can't redirect output if we've got an active mmap() */
11825 if (atomic_read(&event->mmap_count))
11828 if (output_event) {
11829 /* get the rb we want to redirect to */
11830 rb = ring_buffer_get(output_event);
11835 ring_buffer_attach(event, rb);
11839 mutex_unlock(&event->mmap_mutex);
11845 static void mutex_lock_double(struct mutex *a, struct mutex *b)
11851 mutex_lock_nested(b, SINGLE_DEPTH_NESTING);
11854 static int perf_event_set_clock(struct perf_event *event, clockid_t clk_id)
11856 bool nmi_safe = false;
11859 case CLOCK_MONOTONIC:
11860 event->clock = &ktime_get_mono_fast_ns;
11864 case CLOCK_MONOTONIC_RAW:
11865 event->clock = &ktime_get_raw_fast_ns;
11869 case CLOCK_REALTIME:
11870 event->clock = &ktime_get_real_ns;
11873 case CLOCK_BOOTTIME:
11874 event->clock = &ktime_get_boottime_ns;
11878 event->clock = &ktime_get_clocktai_ns;
11885 if (!nmi_safe && !(event->pmu->capabilities & PERF_PMU_CAP_NO_NMI))
11892 * Variation on perf_event_ctx_lock_nested(), except we take two context
11895 static struct perf_event_context *
11896 __perf_event_ctx_lock_double(struct perf_event *group_leader,
11897 struct perf_event_context *ctx)
11899 struct perf_event_context *gctx;
11903 gctx = READ_ONCE(group_leader->ctx);
11904 if (!refcount_inc_not_zero(&gctx->refcount)) {
11910 mutex_lock_double(&gctx->mutex, &ctx->mutex);
11912 if (group_leader->ctx != gctx) {
11913 mutex_unlock(&ctx->mutex);
11914 mutex_unlock(&gctx->mutex);
11923 * sys_perf_event_open - open a performance event, associate it to a task/cpu
11925 * @attr_uptr: event_id type attributes for monitoring/sampling
11928 * @group_fd: group leader event fd
11929 * @flags: perf event open flags
11931 SYSCALL_DEFINE5(perf_event_open,
11932 struct perf_event_attr __user *, attr_uptr,
11933 pid_t, pid, int, cpu, int, group_fd, unsigned long, flags)
11935 struct perf_event *group_leader = NULL, *output_event = NULL;
11936 struct perf_event *event, *sibling;
11937 struct perf_event_attr attr;
11938 struct perf_event_context *ctx, *gctx;
11939 struct file *event_file = NULL;
11940 struct fd group = {NULL, 0};
11941 struct task_struct *task = NULL;
11944 int move_group = 0;
11946 int f_flags = O_RDWR;
11947 int cgroup_fd = -1;
11949 /* for future expandability... */
11950 if (flags & ~PERF_FLAG_ALL)
11953 /* Do we allow access to perf_event_open(2) ? */
11954 err = security_perf_event_open(&attr, PERF_SECURITY_OPEN);
11958 err = perf_copy_attr(attr_uptr, &attr);
11962 if (!attr.exclude_kernel) {
11963 err = perf_allow_kernel(&attr);
11968 if (attr.namespaces) {
11969 if (!perfmon_capable())
11974 if (attr.sample_freq > sysctl_perf_event_sample_rate)
11977 if (attr.sample_period & (1ULL << 63))
11981 /* Only privileged users can get physical addresses */
11982 if ((attr.sample_type & PERF_SAMPLE_PHYS_ADDR)) {
11983 err = perf_allow_kernel(&attr);
11988 /* REGS_INTR can leak data, lockdown must prevent this */
11989 if (attr.sample_type & PERF_SAMPLE_REGS_INTR) {
11990 err = security_locked_down(LOCKDOWN_PERF);
11996 * In cgroup mode, the pid argument is used to pass the fd
11997 * opened to the cgroup directory in cgroupfs. The cpu argument
11998 * designates the cpu on which to monitor threads from that
12001 if ((flags & PERF_FLAG_PID_CGROUP) && (pid == -1 || cpu == -1))
12004 if (flags & PERF_FLAG_FD_CLOEXEC)
12005 f_flags |= O_CLOEXEC;
12007 event_fd = get_unused_fd_flags(f_flags);
12011 if (group_fd != -1) {
12012 err = perf_fget_light(group_fd, &group);
12015 group_leader = group.file->private_data;
12016 if (flags & PERF_FLAG_FD_OUTPUT)
12017 output_event = group_leader;
12018 if (flags & PERF_FLAG_FD_NO_GROUP)
12019 group_leader = NULL;
12022 if (pid != -1 && !(flags & PERF_FLAG_PID_CGROUP)) {
12023 task = find_lively_task_by_vpid(pid);
12024 if (IS_ERR(task)) {
12025 err = PTR_ERR(task);
12030 if (task && group_leader &&
12031 group_leader->attr.inherit != attr.inherit) {
12036 if (flags & PERF_FLAG_PID_CGROUP)
12039 event = perf_event_alloc(&attr, cpu, task, group_leader, NULL,
12040 NULL, NULL, cgroup_fd);
12041 if (IS_ERR(event)) {
12042 err = PTR_ERR(event);
12046 if (is_sampling_event(event)) {
12047 if (event->pmu->capabilities & PERF_PMU_CAP_NO_INTERRUPT) {
12054 * Special case software events and allow them to be part of
12055 * any hardware group.
12059 if (attr.use_clockid) {
12060 err = perf_event_set_clock(event, attr.clockid);
12065 if (pmu->task_ctx_nr == perf_sw_context)
12066 event->event_caps |= PERF_EV_CAP_SOFTWARE;
12068 if (group_leader) {
12069 if (is_software_event(event) &&
12070 !in_software_context(group_leader)) {
12072 * If the event is a sw event, but the group_leader
12073 * is on hw context.
12075 * Allow the addition of software events to hw
12076 * groups, this is safe because software events
12077 * never fail to schedule.
12079 pmu = group_leader->ctx->pmu;
12080 } else if (!is_software_event(event) &&
12081 is_software_event(group_leader) &&
12082 (group_leader->group_caps & PERF_EV_CAP_SOFTWARE)) {
12084 * In case the group is a pure software group, and we
12085 * try to add a hardware event, move the whole group to
12086 * the hardware context.
12093 * Get the target context (task or percpu):
12095 ctx = find_get_context(pmu, task, event);
12097 err = PTR_ERR(ctx);
12102 * Look up the group leader (we will attach this event to it):
12104 if (group_leader) {
12108 * Do not allow a recursive hierarchy (this new sibling
12109 * becoming part of another group-sibling):
12111 if (group_leader->group_leader != group_leader)
12114 /* All events in a group should have the same clock */
12115 if (group_leader->clock != event->clock)
12119 * Make sure we're both events for the same CPU;
12120 * grouping events for different CPUs is broken; since
12121 * you can never concurrently schedule them anyhow.
12123 if (group_leader->cpu != event->cpu)
12127 * Make sure we're both on the same task, or both
12130 if (group_leader->ctx->task != ctx->task)
12134 * Do not allow to attach to a group in a different task
12135 * or CPU context. If we're moving SW events, we'll fix
12136 * this up later, so allow that.
12138 if (!move_group && group_leader->ctx != ctx)
12142 * Only a group leader can be exclusive or pinned
12144 if (attr.exclusive || attr.pinned)
12148 if (output_event) {
12149 err = perf_event_set_output(event, output_event);
12154 event_file = anon_inode_getfile("[perf_event]", &perf_fops, event,
12156 if (IS_ERR(event_file)) {
12157 err = PTR_ERR(event_file);
12163 err = down_read_interruptible(&task->signal->exec_update_lock);
12168 * Preserve ptrace permission check for backwards compatibility.
12170 * We must hold exec_update_lock across this and any potential
12171 * perf_install_in_context() call for this new event to
12172 * serialize against exec() altering our credentials (and the
12173 * perf_event_exit_task() that could imply).
12176 if (!perfmon_capable() && !ptrace_may_access(task, PTRACE_MODE_READ_REALCREDS))
12181 gctx = __perf_event_ctx_lock_double(group_leader, ctx);
12183 if (gctx->task == TASK_TOMBSTONE) {
12189 * Check if we raced against another sys_perf_event_open() call
12190 * moving the software group underneath us.
12192 if (!(group_leader->group_caps & PERF_EV_CAP_SOFTWARE)) {
12194 * If someone moved the group out from under us, check
12195 * if this new event wound up on the same ctx, if so
12196 * its the regular !move_group case, otherwise fail.
12202 perf_event_ctx_unlock(group_leader, gctx);
12208 * Failure to create exclusive events returns -EBUSY.
12211 if (!exclusive_event_installable(group_leader, ctx))
12214 for_each_sibling_event(sibling, group_leader) {
12215 if (!exclusive_event_installable(sibling, ctx))
12219 mutex_lock(&ctx->mutex);
12222 if (ctx->task == TASK_TOMBSTONE) {
12227 if (!perf_event_validate_size(event)) {
12234 * Check if the @cpu we're creating an event for is online.
12236 * We use the perf_cpu_context::ctx::mutex to serialize against
12237 * the hotplug notifiers. See perf_event_{init,exit}_cpu().
12239 struct perf_cpu_context *cpuctx =
12240 container_of(ctx, struct perf_cpu_context, ctx);
12242 if (!cpuctx->online) {
12248 if (perf_need_aux_event(event) && !perf_get_aux_event(event, group_leader)) {
12254 * Must be under the same ctx::mutex as perf_install_in_context(),
12255 * because we need to serialize with concurrent event creation.
12257 if (!exclusive_event_installable(event, ctx)) {
12262 WARN_ON_ONCE(ctx->parent_ctx);
12265 * This is the point on no return; we cannot fail hereafter. This is
12266 * where we start modifying current state.
12271 * See perf_event_ctx_lock() for comments on the details
12272 * of swizzling perf_event::ctx.
12274 perf_remove_from_context(group_leader, 0);
12277 for_each_sibling_event(sibling, group_leader) {
12278 perf_remove_from_context(sibling, 0);
12283 * Wait for everybody to stop referencing the events through
12284 * the old lists, before installing it on new lists.
12289 * Install the group siblings before the group leader.
12291 * Because a group leader will try and install the entire group
12292 * (through the sibling list, which is still in-tact), we can
12293 * end up with siblings installed in the wrong context.
12295 * By installing siblings first we NO-OP because they're not
12296 * reachable through the group lists.
12298 for_each_sibling_event(sibling, group_leader) {
12299 perf_event__state_init(sibling);
12300 perf_install_in_context(ctx, sibling, sibling->cpu);
12305 * Removing from the context ends up with disabled
12306 * event. What we want here is event in the initial
12307 * startup state, ready to be add into new context.
12309 perf_event__state_init(group_leader);
12310 perf_install_in_context(ctx, group_leader, group_leader->cpu);
12315 * Precalculate sample_data sizes; do while holding ctx::mutex such
12316 * that we're serialized against further additions and before
12317 * perf_install_in_context() which is the point the event is active and
12318 * can use these values.
12320 perf_event__header_size(event);
12321 perf_event__id_header_size(event);
12323 event->owner = current;
12325 perf_install_in_context(ctx, event, event->cpu);
12326 perf_unpin_context(ctx);
12329 perf_event_ctx_unlock(group_leader, gctx);
12330 mutex_unlock(&ctx->mutex);
12333 up_read(&task->signal->exec_update_lock);
12334 put_task_struct(task);
12337 mutex_lock(¤t->perf_event_mutex);
12338 list_add_tail(&event->owner_entry, ¤t->perf_event_list);
12339 mutex_unlock(¤t->perf_event_mutex);
12342 * Drop the reference on the group_event after placing the
12343 * new event on the sibling_list. This ensures destruction
12344 * of the group leader will find the pointer to itself in
12345 * perf_group_detach().
12348 fd_install(event_fd, event_file);
12353 perf_event_ctx_unlock(group_leader, gctx);
12354 mutex_unlock(&ctx->mutex);
12357 up_read(&task->signal->exec_update_lock);
12361 perf_unpin_context(ctx);
12365 * If event_file is set, the fput() above will have called ->release()
12366 * and that will take care of freeing the event.
12372 put_task_struct(task);
12376 put_unused_fd(event_fd);
12381 * perf_event_create_kernel_counter
12383 * @attr: attributes of the counter to create
12384 * @cpu: cpu in which the counter is bound
12385 * @task: task to profile (NULL for percpu)
12386 * @overflow_handler: callback to trigger when we hit the event
12387 * @context: context data could be used in overflow_handler callback
12389 struct perf_event *
12390 perf_event_create_kernel_counter(struct perf_event_attr *attr, int cpu,
12391 struct task_struct *task,
12392 perf_overflow_handler_t overflow_handler,
12395 struct perf_event_context *ctx;
12396 struct perf_event *event;
12400 * Grouping is not supported for kernel events, neither is 'AUX',
12401 * make sure the caller's intentions are adjusted.
12403 if (attr->aux_output)
12404 return ERR_PTR(-EINVAL);
12406 event = perf_event_alloc(attr, cpu, task, NULL, NULL,
12407 overflow_handler, context, -1);
12408 if (IS_ERR(event)) {
12409 err = PTR_ERR(event);
12413 /* Mark owner so we could distinguish it from user events. */
12414 event->owner = TASK_TOMBSTONE;
12417 * Get the target context (task or percpu):
12419 ctx = find_get_context(event->pmu, task, event);
12421 err = PTR_ERR(ctx);
12425 WARN_ON_ONCE(ctx->parent_ctx);
12426 mutex_lock(&ctx->mutex);
12427 if (ctx->task == TASK_TOMBSTONE) {
12434 * Check if the @cpu we're creating an event for is online.
12436 * We use the perf_cpu_context::ctx::mutex to serialize against
12437 * the hotplug notifiers. See perf_event_{init,exit}_cpu().
12439 struct perf_cpu_context *cpuctx =
12440 container_of(ctx, struct perf_cpu_context, ctx);
12441 if (!cpuctx->online) {
12447 if (!exclusive_event_installable(event, ctx)) {
12452 perf_install_in_context(ctx, event, event->cpu);
12453 perf_unpin_context(ctx);
12454 mutex_unlock(&ctx->mutex);
12459 mutex_unlock(&ctx->mutex);
12460 perf_unpin_context(ctx);
12465 return ERR_PTR(err);
12467 EXPORT_SYMBOL_GPL(perf_event_create_kernel_counter);
12469 void perf_pmu_migrate_context(struct pmu *pmu, int src_cpu, int dst_cpu)
12471 struct perf_event_context *src_ctx;
12472 struct perf_event_context *dst_ctx;
12473 struct perf_event *event, *tmp;
12476 src_ctx = &per_cpu_ptr(pmu->pmu_cpu_context, src_cpu)->ctx;
12477 dst_ctx = &per_cpu_ptr(pmu->pmu_cpu_context, dst_cpu)->ctx;
12480 * See perf_event_ctx_lock() for comments on the details
12481 * of swizzling perf_event::ctx.
12483 mutex_lock_double(&src_ctx->mutex, &dst_ctx->mutex);
12484 list_for_each_entry_safe(event, tmp, &src_ctx->event_list,
12486 perf_remove_from_context(event, 0);
12487 unaccount_event_cpu(event, src_cpu);
12489 list_add(&event->migrate_entry, &events);
12493 * Wait for the events to quiesce before re-instating them.
12498 * Re-instate events in 2 passes.
12500 * Skip over group leaders and only install siblings on this first
12501 * pass, siblings will not get enabled without a leader, however a
12502 * leader will enable its siblings, even if those are still on the old
12505 list_for_each_entry_safe(event, tmp, &events, migrate_entry) {
12506 if (event->group_leader == event)
12509 list_del(&event->migrate_entry);
12510 if (event->state >= PERF_EVENT_STATE_OFF)
12511 event->state = PERF_EVENT_STATE_INACTIVE;
12512 account_event_cpu(event, dst_cpu);
12513 perf_install_in_context(dst_ctx, event, dst_cpu);
12518 * Once all the siblings are setup properly, install the group leaders
12521 list_for_each_entry_safe(event, tmp, &events, migrate_entry) {
12522 list_del(&event->migrate_entry);
12523 if (event->state >= PERF_EVENT_STATE_OFF)
12524 event->state = PERF_EVENT_STATE_INACTIVE;
12525 account_event_cpu(event, dst_cpu);
12526 perf_install_in_context(dst_ctx, event, dst_cpu);
12529 mutex_unlock(&dst_ctx->mutex);
12530 mutex_unlock(&src_ctx->mutex);
12532 EXPORT_SYMBOL_GPL(perf_pmu_migrate_context);
12534 static void sync_child_event(struct perf_event *child_event)
12536 struct perf_event *parent_event = child_event->parent;
12539 if (child_event->attr.inherit_stat) {
12540 struct task_struct *task = child_event->ctx->task;
12542 if (task && task != TASK_TOMBSTONE)
12543 perf_event_read_event(child_event, task);
12546 child_val = perf_event_count(child_event);
12549 * Add back the child's count to the parent's count:
12551 atomic64_add(child_val, &parent_event->child_count);
12552 atomic64_add(child_event->total_time_enabled,
12553 &parent_event->child_total_time_enabled);
12554 atomic64_add(child_event->total_time_running,
12555 &parent_event->child_total_time_running);
12559 perf_event_exit_event(struct perf_event *event, struct perf_event_context *ctx)
12561 struct perf_event *parent_event = event->parent;
12562 unsigned long detach_flags = 0;
12564 if (parent_event) {
12566 * Do not destroy the 'original' grouping; because of the
12567 * context switch optimization the original events could've
12568 * ended up in a random child task.
12570 * If we were to destroy the original group, all group related
12571 * operations would cease to function properly after this
12572 * random child dies.
12574 * Do destroy all inherited groups, we don't care about those
12575 * and being thorough is better.
12577 detach_flags = DETACH_GROUP | DETACH_CHILD;
12578 mutex_lock(&parent_event->child_mutex);
12581 perf_remove_from_context(event, detach_flags);
12583 raw_spin_lock_irq(&ctx->lock);
12584 if (event->state > PERF_EVENT_STATE_EXIT)
12585 perf_event_set_state(event, PERF_EVENT_STATE_EXIT);
12586 raw_spin_unlock_irq(&ctx->lock);
12589 * Child events can be freed.
12591 if (parent_event) {
12592 mutex_unlock(&parent_event->child_mutex);
12594 * Kick perf_poll() for is_event_hup();
12596 perf_event_wakeup(parent_event);
12598 put_event(parent_event);
12603 * Parent events are governed by their filedesc, retain them.
12605 perf_event_wakeup(event);
12608 static void perf_event_exit_task_context(struct task_struct *child, int ctxn)
12610 struct perf_event_context *child_ctx, *clone_ctx = NULL;
12611 struct perf_event *child_event, *next;
12613 WARN_ON_ONCE(child != current);
12615 child_ctx = perf_pin_task_context(child, ctxn);
12620 * In order to reduce the amount of tricky in ctx tear-down, we hold
12621 * ctx::mutex over the entire thing. This serializes against almost
12622 * everything that wants to access the ctx.
12624 * The exception is sys_perf_event_open() /
12625 * perf_event_create_kernel_count() which does find_get_context()
12626 * without ctx::mutex (it cannot because of the move_group double mutex
12627 * lock thing). See the comments in perf_install_in_context().
12629 mutex_lock(&child_ctx->mutex);
12632 * In a single ctx::lock section, de-schedule the events and detach the
12633 * context from the task such that we cannot ever get it scheduled back
12636 raw_spin_lock_irq(&child_ctx->lock);
12637 task_ctx_sched_out(__get_cpu_context(child_ctx), child_ctx, EVENT_ALL);
12640 * Now that the context is inactive, destroy the task <-> ctx relation
12641 * and mark the context dead.
12643 RCU_INIT_POINTER(child->perf_event_ctxp[ctxn], NULL);
12644 put_ctx(child_ctx); /* cannot be last */
12645 WRITE_ONCE(child_ctx->task, TASK_TOMBSTONE);
12646 put_task_struct(current); /* cannot be last */
12648 clone_ctx = unclone_ctx(child_ctx);
12649 raw_spin_unlock_irq(&child_ctx->lock);
12652 put_ctx(clone_ctx);
12655 * Report the task dead after unscheduling the events so that we
12656 * won't get any samples after PERF_RECORD_EXIT. We can however still
12657 * get a few PERF_RECORD_READ events.
12659 perf_event_task(child, child_ctx, 0);
12661 list_for_each_entry_safe(child_event, next, &child_ctx->event_list, event_entry)
12662 perf_event_exit_event(child_event, child_ctx);
12664 mutex_unlock(&child_ctx->mutex);
12666 put_ctx(child_ctx);
12670 * When a child task exits, feed back event values to parent events.
12672 * Can be called with exec_update_lock held when called from
12673 * setup_new_exec().
12675 void perf_event_exit_task(struct task_struct *child)
12677 struct perf_event *event, *tmp;
12680 mutex_lock(&child->perf_event_mutex);
12681 list_for_each_entry_safe(event, tmp, &child->perf_event_list,
12683 list_del_init(&event->owner_entry);
12686 * Ensure the list deletion is visible before we clear
12687 * the owner, closes a race against perf_release() where
12688 * we need to serialize on the owner->perf_event_mutex.
12690 smp_store_release(&event->owner, NULL);
12692 mutex_unlock(&child->perf_event_mutex);
12694 for_each_task_context_nr(ctxn)
12695 perf_event_exit_task_context(child, ctxn);
12698 * The perf_event_exit_task_context calls perf_event_task
12699 * with child's task_ctx, which generates EXIT events for
12700 * child contexts and sets child->perf_event_ctxp[] to NULL.
12701 * At this point we need to send EXIT events to cpu contexts.
12703 perf_event_task(child, NULL, 0);
12706 static void perf_free_event(struct perf_event *event,
12707 struct perf_event_context *ctx)
12709 struct perf_event *parent = event->parent;
12711 if (WARN_ON_ONCE(!parent))
12714 mutex_lock(&parent->child_mutex);
12715 list_del_init(&event->child_list);
12716 mutex_unlock(&parent->child_mutex);
12720 raw_spin_lock_irq(&ctx->lock);
12721 perf_group_detach(event);
12722 list_del_event(event, ctx);
12723 raw_spin_unlock_irq(&ctx->lock);
12728 * Free a context as created by inheritance by perf_event_init_task() below,
12729 * used by fork() in case of fail.
12731 * Even though the task has never lived, the context and events have been
12732 * exposed through the child_list, so we must take care tearing it all down.
12734 void perf_event_free_task(struct task_struct *task)
12736 struct perf_event_context *ctx;
12737 struct perf_event *event, *tmp;
12740 for_each_task_context_nr(ctxn) {
12741 ctx = task->perf_event_ctxp[ctxn];
12745 mutex_lock(&ctx->mutex);
12746 raw_spin_lock_irq(&ctx->lock);
12748 * Destroy the task <-> ctx relation and mark the context dead.
12750 * This is important because even though the task hasn't been
12751 * exposed yet the context has been (through child_list).
12753 RCU_INIT_POINTER(task->perf_event_ctxp[ctxn], NULL);
12754 WRITE_ONCE(ctx->task, TASK_TOMBSTONE);
12755 put_task_struct(task); /* cannot be last */
12756 raw_spin_unlock_irq(&ctx->lock);
12758 list_for_each_entry_safe(event, tmp, &ctx->event_list, event_entry)
12759 perf_free_event(event, ctx);
12761 mutex_unlock(&ctx->mutex);
12764 * perf_event_release_kernel() could've stolen some of our
12765 * child events and still have them on its free_list. In that
12766 * case we must wait for these events to have been freed (in
12767 * particular all their references to this task must've been
12770 * Without this copy_process() will unconditionally free this
12771 * task (irrespective of its reference count) and
12772 * _free_event()'s put_task_struct(event->hw.target) will be a
12775 * Wait for all events to drop their context reference.
12777 wait_var_event(&ctx->refcount, refcount_read(&ctx->refcount) == 1);
12778 put_ctx(ctx); /* must be last */
12782 void perf_event_delayed_put(struct task_struct *task)
12786 for_each_task_context_nr(ctxn)
12787 WARN_ON_ONCE(task->perf_event_ctxp[ctxn]);
12790 struct file *perf_event_get(unsigned int fd)
12792 struct file *file = fget(fd);
12794 return ERR_PTR(-EBADF);
12796 if (file->f_op != &perf_fops) {
12798 return ERR_PTR(-EBADF);
12804 const struct perf_event *perf_get_event(struct file *file)
12806 if (file->f_op != &perf_fops)
12807 return ERR_PTR(-EINVAL);
12809 return file->private_data;
12812 const struct perf_event_attr *perf_event_attrs(struct perf_event *event)
12815 return ERR_PTR(-EINVAL);
12817 return &event->attr;
12821 * Inherit an event from parent task to child task.
12824 * - valid pointer on success
12825 * - NULL for orphaned events
12826 * - IS_ERR() on error
12828 static struct perf_event *
12829 inherit_event(struct perf_event *parent_event,
12830 struct task_struct *parent,
12831 struct perf_event_context *parent_ctx,
12832 struct task_struct *child,
12833 struct perf_event *group_leader,
12834 struct perf_event_context *child_ctx)
12836 enum perf_event_state parent_state = parent_event->state;
12837 struct perf_event *child_event;
12838 unsigned long flags;
12841 * Instead of creating recursive hierarchies of events,
12842 * we link inherited events back to the original parent,
12843 * which has a filp for sure, which we use as the reference
12846 if (parent_event->parent)
12847 parent_event = parent_event->parent;
12849 child_event = perf_event_alloc(&parent_event->attr,
12852 group_leader, parent_event,
12854 if (IS_ERR(child_event))
12855 return child_event;
12858 if ((child_event->attach_state & PERF_ATTACH_TASK_DATA) &&
12859 !child_ctx->task_ctx_data) {
12860 struct pmu *pmu = child_event->pmu;
12862 child_ctx->task_ctx_data = alloc_task_ctx_data(pmu);
12863 if (!child_ctx->task_ctx_data) {
12864 free_event(child_event);
12865 return ERR_PTR(-ENOMEM);
12870 * is_orphaned_event() and list_add_tail(&parent_event->child_list)
12871 * must be under the same lock in order to serialize against
12872 * perf_event_release_kernel(), such that either we must observe
12873 * is_orphaned_event() or they will observe us on the child_list.
12875 mutex_lock(&parent_event->child_mutex);
12876 if (is_orphaned_event(parent_event) ||
12877 !atomic_long_inc_not_zero(&parent_event->refcount)) {
12878 mutex_unlock(&parent_event->child_mutex);
12879 /* task_ctx_data is freed with child_ctx */
12880 free_event(child_event);
12884 get_ctx(child_ctx);
12887 * Make the child state follow the state of the parent event,
12888 * not its attr.disabled bit. We hold the parent's mutex,
12889 * so we won't race with perf_event_{en, dis}able_family.
12891 if (parent_state >= PERF_EVENT_STATE_INACTIVE)
12892 child_event->state = PERF_EVENT_STATE_INACTIVE;
12894 child_event->state = PERF_EVENT_STATE_OFF;
12896 if (parent_event->attr.freq) {
12897 u64 sample_period = parent_event->hw.sample_period;
12898 struct hw_perf_event *hwc = &child_event->hw;
12900 hwc->sample_period = sample_period;
12901 hwc->last_period = sample_period;
12903 local64_set(&hwc->period_left, sample_period);
12906 child_event->ctx = child_ctx;
12907 child_event->overflow_handler = parent_event->overflow_handler;
12908 child_event->overflow_handler_context
12909 = parent_event->overflow_handler_context;
12912 * Precalculate sample_data sizes
12914 perf_event__header_size(child_event);
12915 perf_event__id_header_size(child_event);
12918 * Link it up in the child's context:
12920 raw_spin_lock_irqsave(&child_ctx->lock, flags);
12921 add_event_to_ctx(child_event, child_ctx);
12922 child_event->attach_state |= PERF_ATTACH_CHILD;
12923 raw_spin_unlock_irqrestore(&child_ctx->lock, flags);
12926 * Link this into the parent event's child list
12928 list_add_tail(&child_event->child_list, &parent_event->child_list);
12929 mutex_unlock(&parent_event->child_mutex);
12931 return child_event;
12935 * Inherits an event group.
12937 * This will quietly suppress orphaned events; !inherit_event() is not an error.
12938 * This matches with perf_event_release_kernel() removing all child events.
12944 static int inherit_group(struct perf_event *parent_event,
12945 struct task_struct *parent,
12946 struct perf_event_context *parent_ctx,
12947 struct task_struct *child,
12948 struct perf_event_context *child_ctx)
12950 struct perf_event *leader;
12951 struct perf_event *sub;
12952 struct perf_event *child_ctr;
12954 leader = inherit_event(parent_event, parent, parent_ctx,
12955 child, NULL, child_ctx);
12956 if (IS_ERR(leader))
12957 return PTR_ERR(leader);
12959 * @leader can be NULL here because of is_orphaned_event(). In this
12960 * case inherit_event() will create individual events, similar to what
12961 * perf_group_detach() would do anyway.
12963 for_each_sibling_event(sub, parent_event) {
12964 child_ctr = inherit_event(sub, parent, parent_ctx,
12965 child, leader, child_ctx);
12966 if (IS_ERR(child_ctr))
12967 return PTR_ERR(child_ctr);
12969 if (sub->aux_event == parent_event && child_ctr &&
12970 !perf_get_aux_event(child_ctr, leader))
12977 * Creates the child task context and tries to inherit the event-group.
12979 * Clears @inherited_all on !attr.inherited or error. Note that we'll leave
12980 * inherited_all set when we 'fail' to inherit an orphaned event; this is
12981 * consistent with perf_event_release_kernel() removing all child events.
12988 inherit_task_group(struct perf_event *event, struct task_struct *parent,
12989 struct perf_event_context *parent_ctx,
12990 struct task_struct *child, int ctxn,
12991 u64 clone_flags, int *inherited_all)
12994 struct perf_event_context *child_ctx;
12996 if (!event->attr.inherit ||
12997 (event->attr.inherit_thread && !(clone_flags & CLONE_THREAD)) ||
12998 /* Do not inherit if sigtrap and signal handlers were cleared. */
12999 (event->attr.sigtrap && (clone_flags & CLONE_CLEAR_SIGHAND))) {
13000 *inherited_all = 0;
13004 child_ctx = child->perf_event_ctxp[ctxn];
13007 * This is executed from the parent task context, so
13008 * inherit events that have been marked for cloning.
13009 * First allocate and initialize a context for the
13012 child_ctx = alloc_perf_context(parent_ctx->pmu, child);
13016 child->perf_event_ctxp[ctxn] = child_ctx;
13019 ret = inherit_group(event, parent, parent_ctx,
13023 *inherited_all = 0;
13029 * Initialize the perf_event context in task_struct
13031 static int perf_event_init_context(struct task_struct *child, int ctxn,
13034 struct perf_event_context *child_ctx, *parent_ctx;
13035 struct perf_event_context *cloned_ctx;
13036 struct perf_event *event;
13037 struct task_struct *parent = current;
13038 int inherited_all = 1;
13039 unsigned long flags;
13042 if (likely(!parent->perf_event_ctxp[ctxn]))
13046 * If the parent's context is a clone, pin it so it won't get
13047 * swapped under us.
13049 parent_ctx = perf_pin_task_context(parent, ctxn);
13054 * No need to check if parent_ctx != NULL here; since we saw
13055 * it non-NULL earlier, the only reason for it to become NULL
13056 * is if we exit, and since we're currently in the middle of
13057 * a fork we can't be exiting at the same time.
13061 * Lock the parent list. No need to lock the child - not PID
13062 * hashed yet and not running, so nobody can access it.
13064 mutex_lock(&parent_ctx->mutex);
13067 * We dont have to disable NMIs - we are only looking at
13068 * the list, not manipulating it:
13070 perf_event_groups_for_each(event, &parent_ctx->pinned_groups) {
13071 ret = inherit_task_group(event, parent, parent_ctx,
13072 child, ctxn, clone_flags,
13079 * We can't hold ctx->lock when iterating the ->flexible_group list due
13080 * to allocations, but we need to prevent rotation because
13081 * rotate_ctx() will change the list from interrupt context.
13083 raw_spin_lock_irqsave(&parent_ctx->lock, flags);
13084 parent_ctx->rotate_disable = 1;
13085 raw_spin_unlock_irqrestore(&parent_ctx->lock, flags);
13087 perf_event_groups_for_each(event, &parent_ctx->flexible_groups) {
13088 ret = inherit_task_group(event, parent, parent_ctx,
13089 child, ctxn, clone_flags,
13095 raw_spin_lock_irqsave(&parent_ctx->lock, flags);
13096 parent_ctx->rotate_disable = 0;
13098 child_ctx = child->perf_event_ctxp[ctxn];
13100 if (child_ctx && inherited_all) {
13102 * Mark the child context as a clone of the parent
13103 * context, or of whatever the parent is a clone of.
13105 * Note that if the parent is a clone, the holding of
13106 * parent_ctx->lock avoids it from being uncloned.
13108 cloned_ctx = parent_ctx->parent_ctx;
13110 child_ctx->parent_ctx = cloned_ctx;
13111 child_ctx->parent_gen = parent_ctx->parent_gen;
13113 child_ctx->parent_ctx = parent_ctx;
13114 child_ctx->parent_gen = parent_ctx->generation;
13116 get_ctx(child_ctx->parent_ctx);
13119 raw_spin_unlock_irqrestore(&parent_ctx->lock, flags);
13121 mutex_unlock(&parent_ctx->mutex);
13123 perf_unpin_context(parent_ctx);
13124 put_ctx(parent_ctx);
13130 * Initialize the perf_event context in task_struct
13132 int perf_event_init_task(struct task_struct *child, u64 clone_flags)
13136 memset(child->perf_event_ctxp, 0, sizeof(child->perf_event_ctxp));
13137 mutex_init(&child->perf_event_mutex);
13138 INIT_LIST_HEAD(&child->perf_event_list);
13140 for_each_task_context_nr(ctxn) {
13141 ret = perf_event_init_context(child, ctxn, clone_flags);
13143 perf_event_free_task(child);
13151 static void __init perf_event_init_all_cpus(void)
13153 struct swevent_htable *swhash;
13156 zalloc_cpumask_var(&perf_online_mask, GFP_KERNEL);
13158 for_each_possible_cpu(cpu) {
13159 swhash = &per_cpu(swevent_htable, cpu);
13160 mutex_init(&swhash->hlist_mutex);
13161 INIT_LIST_HEAD(&per_cpu(active_ctx_list, cpu));
13163 INIT_LIST_HEAD(&per_cpu(pmu_sb_events.list, cpu));
13164 raw_spin_lock_init(&per_cpu(pmu_sb_events.lock, cpu));
13166 #ifdef CONFIG_CGROUP_PERF
13167 INIT_LIST_HEAD(&per_cpu(cgrp_cpuctx_list, cpu));
13169 INIT_LIST_HEAD(&per_cpu(sched_cb_list, cpu));
13173 static void perf_swevent_init_cpu(unsigned int cpu)
13175 struct swevent_htable *swhash = &per_cpu(swevent_htable, cpu);
13177 mutex_lock(&swhash->hlist_mutex);
13178 if (swhash->hlist_refcount > 0 && !swevent_hlist_deref(swhash)) {
13179 struct swevent_hlist *hlist;
13181 hlist = kzalloc_node(sizeof(*hlist), GFP_KERNEL, cpu_to_node(cpu));
13183 rcu_assign_pointer(swhash->swevent_hlist, hlist);
13185 mutex_unlock(&swhash->hlist_mutex);
13188 #if defined CONFIG_HOTPLUG_CPU || defined CONFIG_KEXEC_CORE
13189 static void __perf_event_exit_context(void *__info)
13191 struct perf_event_context *ctx = __info;
13192 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
13193 struct perf_event *event;
13195 raw_spin_lock(&ctx->lock);
13196 ctx_sched_out(ctx, cpuctx, EVENT_TIME);
13197 list_for_each_entry(event, &ctx->event_list, event_entry)
13198 __perf_remove_from_context(event, cpuctx, ctx, (void *)DETACH_GROUP);
13199 raw_spin_unlock(&ctx->lock);
13202 static void perf_event_exit_cpu_context(int cpu)
13204 struct perf_cpu_context *cpuctx;
13205 struct perf_event_context *ctx;
13208 mutex_lock(&pmus_lock);
13209 list_for_each_entry(pmu, &pmus, entry) {
13210 cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
13211 ctx = &cpuctx->ctx;
13213 mutex_lock(&ctx->mutex);
13214 smp_call_function_single(cpu, __perf_event_exit_context, ctx, 1);
13215 cpuctx->online = 0;
13216 mutex_unlock(&ctx->mutex);
13218 cpumask_clear_cpu(cpu, perf_online_mask);
13219 mutex_unlock(&pmus_lock);
13223 static void perf_event_exit_cpu_context(int cpu) { }
13227 int perf_event_init_cpu(unsigned int cpu)
13229 struct perf_cpu_context *cpuctx;
13230 struct perf_event_context *ctx;
13233 perf_swevent_init_cpu(cpu);
13235 mutex_lock(&pmus_lock);
13236 cpumask_set_cpu(cpu, perf_online_mask);
13237 list_for_each_entry(pmu, &pmus, entry) {
13238 cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
13239 ctx = &cpuctx->ctx;
13241 mutex_lock(&ctx->mutex);
13242 cpuctx->online = 1;
13243 mutex_unlock(&ctx->mutex);
13245 mutex_unlock(&pmus_lock);
13250 int perf_event_exit_cpu(unsigned int cpu)
13252 perf_event_exit_cpu_context(cpu);
13257 perf_reboot(struct notifier_block *notifier, unsigned long val, void *v)
13261 for_each_online_cpu(cpu)
13262 perf_event_exit_cpu(cpu);
13268 * Run the perf reboot notifier at the very last possible moment so that
13269 * the generic watchdog code runs as long as possible.
13271 static struct notifier_block perf_reboot_notifier = {
13272 .notifier_call = perf_reboot,
13273 .priority = INT_MIN,
13276 void __init perf_event_init(void)
13280 idr_init(&pmu_idr);
13282 perf_event_init_all_cpus();
13283 init_srcu_struct(&pmus_srcu);
13284 perf_pmu_register(&perf_swevent, "software", PERF_TYPE_SOFTWARE);
13285 perf_pmu_register(&perf_cpu_clock, NULL, -1);
13286 perf_pmu_register(&perf_task_clock, NULL, -1);
13287 perf_tp_register();
13288 perf_event_init_cpu(smp_processor_id());
13289 register_reboot_notifier(&perf_reboot_notifier);
13291 ret = init_hw_breakpoint();
13292 WARN(ret, "hw_breakpoint initialization failed with: %d", ret);
13294 perf_event_cache = KMEM_CACHE(perf_event, SLAB_PANIC);
13297 * Build time assertion that we keep the data_head at the intended
13298 * location. IOW, validation we got the __reserved[] size right.
13300 BUILD_BUG_ON((offsetof(struct perf_event_mmap_page, data_head))
13304 ssize_t perf_event_sysfs_show(struct device *dev, struct device_attribute *attr,
13307 struct perf_pmu_events_attr *pmu_attr =
13308 container_of(attr, struct perf_pmu_events_attr, attr);
13310 if (pmu_attr->event_str)
13311 return sprintf(page, "%s\n", pmu_attr->event_str);
13315 EXPORT_SYMBOL_GPL(perf_event_sysfs_show);
13317 static int __init perf_event_sysfs_init(void)
13322 mutex_lock(&pmus_lock);
13324 ret = bus_register(&pmu_bus);
13328 list_for_each_entry(pmu, &pmus, entry) {
13329 if (!pmu->name || pmu->type < 0)
13332 ret = pmu_dev_alloc(pmu);
13333 WARN(ret, "Failed to register pmu: %s, reason %d\n", pmu->name, ret);
13335 pmu_bus_running = 1;
13339 mutex_unlock(&pmus_lock);
13343 device_initcall(perf_event_sysfs_init);
13345 #ifdef CONFIG_CGROUP_PERF
13346 static struct cgroup_subsys_state *
13347 perf_cgroup_css_alloc(struct cgroup_subsys_state *parent_css)
13349 struct perf_cgroup *jc;
13351 jc = kzalloc(sizeof(*jc), GFP_KERNEL);
13353 return ERR_PTR(-ENOMEM);
13355 jc->info = alloc_percpu(struct perf_cgroup_info);
13358 return ERR_PTR(-ENOMEM);
13364 static void perf_cgroup_css_free(struct cgroup_subsys_state *css)
13366 struct perf_cgroup *jc = container_of(css, struct perf_cgroup, css);
13368 free_percpu(jc->info);
13372 static int perf_cgroup_css_online(struct cgroup_subsys_state *css)
13374 perf_event_cgroup(css->cgroup);
13378 static int __perf_cgroup_move(void *info)
13380 struct task_struct *task = info;
13382 perf_cgroup_switch(task, PERF_CGROUP_SWOUT | PERF_CGROUP_SWIN);
13387 static void perf_cgroup_attach(struct cgroup_taskset *tset)
13389 struct task_struct *task;
13390 struct cgroup_subsys_state *css;
13392 cgroup_taskset_for_each(task, css, tset)
13393 task_function_call(task, __perf_cgroup_move, task);
13396 struct cgroup_subsys perf_event_cgrp_subsys = {
13397 .css_alloc = perf_cgroup_css_alloc,
13398 .css_free = perf_cgroup_css_free,
13399 .css_online = perf_cgroup_css_online,
13400 .attach = perf_cgroup_attach,
13402 * Implicitly enable on dfl hierarchy so that perf events can
13403 * always be filtered by cgroup2 path as long as perf_event
13404 * controller is not mounted on a legacy hierarchy.
13406 .implicit_on_dfl = true,
13409 #endif /* CONFIG_CGROUP_PERF */