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->hw.flags & PERF_EVENT_FLAG_USER_READ_CNT)
1813 if (event->attr.inherit_stat)
1816 if (event->state > PERF_EVENT_STATE_OFF)
1817 perf_cgroup_event_enable(event, ctx);
1823 * Initialize event state based on the perf_event_attr::disabled.
1825 static inline void perf_event__state_init(struct perf_event *event)
1827 event->state = event->attr.disabled ? PERF_EVENT_STATE_OFF :
1828 PERF_EVENT_STATE_INACTIVE;
1831 static void __perf_event_read_size(struct perf_event *event, int nr_siblings)
1833 int entry = sizeof(u64); /* value */
1837 if (event->attr.read_format & PERF_FORMAT_TOTAL_TIME_ENABLED)
1838 size += sizeof(u64);
1840 if (event->attr.read_format & PERF_FORMAT_TOTAL_TIME_RUNNING)
1841 size += sizeof(u64);
1843 if (event->attr.read_format & PERF_FORMAT_ID)
1844 entry += sizeof(u64);
1846 if (event->attr.read_format & PERF_FORMAT_GROUP) {
1848 size += sizeof(u64);
1852 event->read_size = size;
1855 static void __perf_event_header_size(struct perf_event *event, u64 sample_type)
1857 struct perf_sample_data *data;
1860 if (sample_type & PERF_SAMPLE_IP)
1861 size += sizeof(data->ip);
1863 if (sample_type & PERF_SAMPLE_ADDR)
1864 size += sizeof(data->addr);
1866 if (sample_type & PERF_SAMPLE_PERIOD)
1867 size += sizeof(data->period);
1869 if (sample_type & PERF_SAMPLE_WEIGHT_TYPE)
1870 size += sizeof(data->weight.full);
1872 if (sample_type & PERF_SAMPLE_READ)
1873 size += event->read_size;
1875 if (sample_type & PERF_SAMPLE_DATA_SRC)
1876 size += sizeof(data->data_src.val);
1878 if (sample_type & PERF_SAMPLE_TRANSACTION)
1879 size += sizeof(data->txn);
1881 if (sample_type & PERF_SAMPLE_PHYS_ADDR)
1882 size += sizeof(data->phys_addr);
1884 if (sample_type & PERF_SAMPLE_CGROUP)
1885 size += sizeof(data->cgroup);
1887 if (sample_type & PERF_SAMPLE_DATA_PAGE_SIZE)
1888 size += sizeof(data->data_page_size);
1890 if (sample_type & PERF_SAMPLE_CODE_PAGE_SIZE)
1891 size += sizeof(data->code_page_size);
1893 event->header_size = size;
1897 * Called at perf_event creation and when events are attached/detached from a
1900 static void perf_event__header_size(struct perf_event *event)
1902 __perf_event_read_size(event,
1903 event->group_leader->nr_siblings);
1904 __perf_event_header_size(event, event->attr.sample_type);
1907 static void perf_event__id_header_size(struct perf_event *event)
1909 struct perf_sample_data *data;
1910 u64 sample_type = event->attr.sample_type;
1913 if (sample_type & PERF_SAMPLE_TID)
1914 size += sizeof(data->tid_entry);
1916 if (sample_type & PERF_SAMPLE_TIME)
1917 size += sizeof(data->time);
1919 if (sample_type & PERF_SAMPLE_IDENTIFIER)
1920 size += sizeof(data->id);
1922 if (sample_type & PERF_SAMPLE_ID)
1923 size += sizeof(data->id);
1925 if (sample_type & PERF_SAMPLE_STREAM_ID)
1926 size += sizeof(data->stream_id);
1928 if (sample_type & PERF_SAMPLE_CPU)
1929 size += sizeof(data->cpu_entry);
1931 event->id_header_size = size;
1934 static bool perf_event_validate_size(struct perf_event *event)
1937 * The values computed here will be over-written when we actually
1940 __perf_event_read_size(event, event->group_leader->nr_siblings + 1);
1941 __perf_event_header_size(event, event->attr.sample_type & ~PERF_SAMPLE_READ);
1942 perf_event__id_header_size(event);
1945 * Sum the lot; should not exceed the 64k limit we have on records.
1946 * Conservative limit to allow for callchains and other variable fields.
1948 if (event->read_size + event->header_size +
1949 event->id_header_size + sizeof(struct perf_event_header) >= 16*1024)
1955 static void perf_group_attach(struct perf_event *event)
1957 struct perf_event *group_leader = event->group_leader, *pos;
1959 lockdep_assert_held(&event->ctx->lock);
1962 * We can have double attach due to group movement in perf_event_open.
1964 if (event->attach_state & PERF_ATTACH_GROUP)
1967 event->attach_state |= PERF_ATTACH_GROUP;
1969 if (group_leader == event)
1972 WARN_ON_ONCE(group_leader->ctx != event->ctx);
1974 group_leader->group_caps &= event->event_caps;
1976 list_add_tail(&event->sibling_list, &group_leader->sibling_list);
1977 group_leader->nr_siblings++;
1979 perf_event__header_size(group_leader);
1981 for_each_sibling_event(pos, group_leader)
1982 perf_event__header_size(pos);
1986 * Remove an event from the lists for its context.
1987 * Must be called with ctx->mutex and ctx->lock held.
1990 list_del_event(struct perf_event *event, struct perf_event_context *ctx)
1992 WARN_ON_ONCE(event->ctx != ctx);
1993 lockdep_assert_held(&ctx->lock);
1996 * We can have double detach due to exit/hot-unplug + close.
1998 if (!(event->attach_state & PERF_ATTACH_CONTEXT))
2001 event->attach_state &= ~PERF_ATTACH_CONTEXT;
2004 if (event->hw.flags & PERF_EVENT_FLAG_USER_READ_CNT)
2006 if (event->attr.inherit_stat)
2009 list_del_rcu(&event->event_entry);
2011 if (event->group_leader == event)
2012 del_event_from_groups(event, ctx);
2015 * If event was in error state, then keep it
2016 * that way, otherwise bogus counts will be
2017 * returned on read(). The only way to get out
2018 * of error state is by explicit re-enabling
2021 if (event->state > PERF_EVENT_STATE_OFF) {
2022 perf_cgroup_event_disable(event, ctx);
2023 perf_event_set_state(event, PERF_EVENT_STATE_OFF);
2030 perf_aux_output_match(struct perf_event *event, struct perf_event *aux_event)
2032 if (!has_aux(aux_event))
2035 if (!event->pmu->aux_output_match)
2038 return event->pmu->aux_output_match(aux_event);
2041 static void put_event(struct perf_event *event);
2042 static void event_sched_out(struct perf_event *event,
2043 struct perf_cpu_context *cpuctx,
2044 struct perf_event_context *ctx);
2046 static void perf_put_aux_event(struct perf_event *event)
2048 struct perf_event_context *ctx = event->ctx;
2049 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
2050 struct perf_event *iter;
2053 * If event uses aux_event tear down the link
2055 if (event->aux_event) {
2056 iter = event->aux_event;
2057 event->aux_event = NULL;
2063 * If the event is an aux_event, tear down all links to
2064 * it from other events.
2066 for_each_sibling_event(iter, event->group_leader) {
2067 if (iter->aux_event != event)
2070 iter->aux_event = NULL;
2074 * If it's ACTIVE, schedule it out and put it into ERROR
2075 * state so that we don't try to schedule it again. Note
2076 * that perf_event_enable() will clear the ERROR status.
2078 event_sched_out(iter, cpuctx, ctx);
2079 perf_event_set_state(event, PERF_EVENT_STATE_ERROR);
2083 static bool perf_need_aux_event(struct perf_event *event)
2085 return !!event->attr.aux_output || !!event->attr.aux_sample_size;
2088 static int perf_get_aux_event(struct perf_event *event,
2089 struct perf_event *group_leader)
2092 * Our group leader must be an aux event if we want to be
2093 * an aux_output. This way, the aux event will precede its
2094 * aux_output events in the group, and therefore will always
2101 * aux_output and aux_sample_size are mutually exclusive.
2103 if (event->attr.aux_output && event->attr.aux_sample_size)
2106 if (event->attr.aux_output &&
2107 !perf_aux_output_match(event, group_leader))
2110 if (event->attr.aux_sample_size && !group_leader->pmu->snapshot_aux)
2113 if (!atomic_long_inc_not_zero(&group_leader->refcount))
2117 * Link aux_outputs to their aux event; this is undone in
2118 * perf_group_detach() by perf_put_aux_event(). When the
2119 * group in torn down, the aux_output events loose their
2120 * link to the aux_event and can't schedule any more.
2122 event->aux_event = group_leader;
2127 static inline struct list_head *get_event_list(struct perf_event *event)
2129 struct perf_event_context *ctx = event->ctx;
2130 return event->attr.pinned ? &ctx->pinned_active : &ctx->flexible_active;
2134 * Events that have PERF_EV_CAP_SIBLING require being part of a group and
2135 * cannot exist on their own, schedule them out and move them into the ERROR
2136 * state. Also see _perf_event_enable(), it will not be able to recover
2139 static inline void perf_remove_sibling_event(struct perf_event *event)
2141 struct perf_event_context *ctx = event->ctx;
2142 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
2144 event_sched_out(event, cpuctx, ctx);
2145 perf_event_set_state(event, PERF_EVENT_STATE_ERROR);
2148 static void perf_group_detach(struct perf_event *event)
2150 struct perf_event *leader = event->group_leader;
2151 struct perf_event *sibling, *tmp;
2152 struct perf_event_context *ctx = event->ctx;
2154 lockdep_assert_held(&ctx->lock);
2157 * We can have double detach due to exit/hot-unplug + close.
2159 if (!(event->attach_state & PERF_ATTACH_GROUP))
2162 event->attach_state &= ~PERF_ATTACH_GROUP;
2164 perf_put_aux_event(event);
2167 * If this is a sibling, remove it from its group.
2169 if (leader != event) {
2170 list_del_init(&event->sibling_list);
2171 event->group_leader->nr_siblings--;
2176 * If this was a group event with sibling events then
2177 * upgrade the siblings to singleton events by adding them
2178 * to whatever list we are on.
2180 list_for_each_entry_safe(sibling, tmp, &event->sibling_list, sibling_list) {
2182 if (sibling->event_caps & PERF_EV_CAP_SIBLING)
2183 perf_remove_sibling_event(sibling);
2185 sibling->group_leader = sibling;
2186 list_del_init(&sibling->sibling_list);
2188 /* Inherit group flags from the previous leader */
2189 sibling->group_caps = event->group_caps;
2191 if (!RB_EMPTY_NODE(&event->group_node)) {
2192 add_event_to_groups(sibling, event->ctx);
2194 if (sibling->state == PERF_EVENT_STATE_ACTIVE)
2195 list_add_tail(&sibling->active_list, get_event_list(sibling));
2198 WARN_ON_ONCE(sibling->ctx != event->ctx);
2202 for_each_sibling_event(tmp, leader)
2203 perf_event__header_size(tmp);
2205 perf_event__header_size(leader);
2208 static void sync_child_event(struct perf_event *child_event);
2210 static void perf_child_detach(struct perf_event *event)
2212 struct perf_event *parent_event = event->parent;
2214 if (!(event->attach_state & PERF_ATTACH_CHILD))
2217 event->attach_state &= ~PERF_ATTACH_CHILD;
2219 if (WARN_ON_ONCE(!parent_event))
2222 lockdep_assert_held(&parent_event->child_mutex);
2224 sync_child_event(event);
2225 list_del_init(&event->child_list);
2228 static bool is_orphaned_event(struct perf_event *event)
2230 return event->state == PERF_EVENT_STATE_DEAD;
2233 static inline int __pmu_filter_match(struct perf_event *event)
2235 struct pmu *pmu = event->pmu;
2236 return pmu->filter_match ? pmu->filter_match(event) : 1;
2240 * Check whether we should attempt to schedule an event group based on
2241 * PMU-specific filtering. An event group can consist of HW and SW events,
2242 * potentially with a SW leader, so we must check all the filters, to
2243 * determine whether a group is schedulable:
2245 static inline int pmu_filter_match(struct perf_event *event)
2247 struct perf_event *sibling;
2249 if (!__pmu_filter_match(event))
2252 for_each_sibling_event(sibling, event) {
2253 if (!__pmu_filter_match(sibling))
2261 event_filter_match(struct perf_event *event)
2263 return (event->cpu == -1 || event->cpu == smp_processor_id()) &&
2264 perf_cgroup_match(event) && pmu_filter_match(event);
2268 event_sched_out(struct perf_event *event,
2269 struct perf_cpu_context *cpuctx,
2270 struct perf_event_context *ctx)
2272 enum perf_event_state state = PERF_EVENT_STATE_INACTIVE;
2274 WARN_ON_ONCE(event->ctx != ctx);
2275 lockdep_assert_held(&ctx->lock);
2277 if (event->state != PERF_EVENT_STATE_ACTIVE)
2281 * Asymmetry; we only schedule events _IN_ through ctx_sched_in(), but
2282 * we can schedule events _OUT_ individually through things like
2283 * __perf_remove_from_context().
2285 list_del_init(&event->active_list);
2287 perf_pmu_disable(event->pmu);
2289 event->pmu->del(event, 0);
2292 if (READ_ONCE(event->pending_disable) >= 0) {
2293 WRITE_ONCE(event->pending_disable, -1);
2294 perf_cgroup_event_disable(event, ctx);
2295 state = PERF_EVENT_STATE_OFF;
2297 perf_event_set_state(event, state);
2299 if (!is_software_event(event))
2300 cpuctx->active_oncpu--;
2301 if (!--ctx->nr_active)
2302 perf_event_ctx_deactivate(ctx);
2303 if (event->attr.freq && event->attr.sample_freq)
2305 if (event->attr.exclusive || !cpuctx->active_oncpu)
2306 cpuctx->exclusive = 0;
2308 perf_pmu_enable(event->pmu);
2312 group_sched_out(struct perf_event *group_event,
2313 struct perf_cpu_context *cpuctx,
2314 struct perf_event_context *ctx)
2316 struct perf_event *event;
2318 if (group_event->state != PERF_EVENT_STATE_ACTIVE)
2321 perf_pmu_disable(ctx->pmu);
2323 event_sched_out(group_event, cpuctx, ctx);
2326 * Schedule out siblings (if any):
2328 for_each_sibling_event(event, group_event)
2329 event_sched_out(event, cpuctx, ctx);
2331 perf_pmu_enable(ctx->pmu);
2334 #define DETACH_GROUP 0x01UL
2335 #define DETACH_CHILD 0x02UL
2338 * Cross CPU call to remove a performance event
2340 * We disable the event on the hardware level first. After that we
2341 * remove it from the context list.
2344 __perf_remove_from_context(struct perf_event *event,
2345 struct perf_cpu_context *cpuctx,
2346 struct perf_event_context *ctx,
2349 unsigned long flags = (unsigned long)info;
2351 if (ctx->is_active & EVENT_TIME) {
2352 update_context_time(ctx);
2353 update_cgrp_time_from_cpuctx(cpuctx);
2356 event_sched_out(event, cpuctx, ctx);
2357 if (flags & DETACH_GROUP)
2358 perf_group_detach(event);
2359 if (flags & DETACH_CHILD)
2360 perf_child_detach(event);
2361 list_del_event(event, ctx);
2363 if (!ctx->nr_events && ctx->is_active) {
2365 ctx->rotate_necessary = 0;
2367 WARN_ON_ONCE(cpuctx->task_ctx != ctx);
2368 cpuctx->task_ctx = NULL;
2374 * Remove the event from a task's (or a CPU's) list of events.
2376 * If event->ctx is a cloned context, callers must make sure that
2377 * every task struct that event->ctx->task could possibly point to
2378 * remains valid. This is OK when called from perf_release since
2379 * that only calls us on the top-level context, which can't be a clone.
2380 * When called from perf_event_exit_task, it's OK because the
2381 * context has been detached from its task.
2383 static void perf_remove_from_context(struct perf_event *event, unsigned long flags)
2385 struct perf_event_context *ctx = event->ctx;
2387 lockdep_assert_held(&ctx->mutex);
2390 * Because of perf_event_exit_task(), perf_remove_from_context() ought
2391 * to work in the face of TASK_TOMBSTONE, unlike every other
2392 * event_function_call() user.
2394 raw_spin_lock_irq(&ctx->lock);
2395 if (!ctx->is_active) {
2396 __perf_remove_from_context(event, __get_cpu_context(ctx),
2397 ctx, (void *)flags);
2398 raw_spin_unlock_irq(&ctx->lock);
2401 raw_spin_unlock_irq(&ctx->lock);
2403 event_function_call(event, __perf_remove_from_context, (void *)flags);
2407 * Cross CPU call to disable a performance event
2409 static void __perf_event_disable(struct perf_event *event,
2410 struct perf_cpu_context *cpuctx,
2411 struct perf_event_context *ctx,
2414 if (event->state < PERF_EVENT_STATE_INACTIVE)
2417 if (ctx->is_active & EVENT_TIME) {
2418 update_context_time(ctx);
2419 update_cgrp_time_from_event(event);
2422 if (event == event->group_leader)
2423 group_sched_out(event, cpuctx, ctx);
2425 event_sched_out(event, cpuctx, ctx);
2427 perf_event_set_state(event, PERF_EVENT_STATE_OFF);
2428 perf_cgroup_event_disable(event, ctx);
2434 * If event->ctx is a cloned context, callers must make sure that
2435 * every task struct that event->ctx->task could possibly point to
2436 * remains valid. This condition is satisfied when called through
2437 * perf_event_for_each_child or perf_event_for_each because they
2438 * hold the top-level event's child_mutex, so any descendant that
2439 * goes to exit will block in perf_event_exit_event().
2441 * When called from perf_pending_event it's OK because event->ctx
2442 * is the current context on this CPU and preemption is disabled,
2443 * hence we can't get into perf_event_task_sched_out for this context.
2445 static void _perf_event_disable(struct perf_event *event)
2447 struct perf_event_context *ctx = event->ctx;
2449 raw_spin_lock_irq(&ctx->lock);
2450 if (event->state <= PERF_EVENT_STATE_OFF) {
2451 raw_spin_unlock_irq(&ctx->lock);
2454 raw_spin_unlock_irq(&ctx->lock);
2456 event_function_call(event, __perf_event_disable, NULL);
2459 void perf_event_disable_local(struct perf_event *event)
2461 event_function_local(event, __perf_event_disable, NULL);
2465 * Strictly speaking kernel users cannot create groups and therefore this
2466 * interface does not need the perf_event_ctx_lock() magic.
2468 void perf_event_disable(struct perf_event *event)
2470 struct perf_event_context *ctx;
2472 ctx = perf_event_ctx_lock(event);
2473 _perf_event_disable(event);
2474 perf_event_ctx_unlock(event, ctx);
2476 EXPORT_SYMBOL_GPL(perf_event_disable);
2478 void perf_event_disable_inatomic(struct perf_event *event)
2480 WRITE_ONCE(event->pending_disable, smp_processor_id());
2481 /* can fail, see perf_pending_event_disable() */
2482 irq_work_queue(&event->pending);
2485 static void perf_set_shadow_time(struct perf_event *event,
2486 struct perf_event_context *ctx)
2489 * use the correct time source for the time snapshot
2491 * We could get by without this by leveraging the
2492 * fact that to get to this function, the caller
2493 * has most likely already called update_context_time()
2494 * and update_cgrp_time_xx() and thus both timestamp
2495 * are identical (or very close). Given that tstamp is,
2496 * already adjusted for cgroup, we could say that:
2497 * tstamp - ctx->timestamp
2499 * tstamp - cgrp->timestamp.
2501 * Then, in perf_output_read(), the calculation would
2502 * work with no changes because:
2503 * - event is guaranteed scheduled in
2504 * - no scheduled out in between
2505 * - thus the timestamp would be the same
2507 * But this is a bit hairy.
2509 * So instead, we have an explicit cgroup call to remain
2510 * within the time source all along. We believe it
2511 * is cleaner and simpler to understand.
2513 if (is_cgroup_event(event))
2514 perf_cgroup_set_shadow_time(event, event->tstamp);
2516 event->shadow_ctx_time = event->tstamp - ctx->timestamp;
2519 #define MAX_INTERRUPTS (~0ULL)
2521 static void perf_log_throttle(struct perf_event *event, int enable);
2522 static void perf_log_itrace_start(struct perf_event *event);
2525 event_sched_in(struct perf_event *event,
2526 struct perf_cpu_context *cpuctx,
2527 struct perf_event_context *ctx)
2531 WARN_ON_ONCE(event->ctx != ctx);
2533 lockdep_assert_held(&ctx->lock);
2535 if (event->state <= PERF_EVENT_STATE_OFF)
2538 WRITE_ONCE(event->oncpu, smp_processor_id());
2540 * Order event::oncpu write to happen before the ACTIVE state is
2541 * visible. This allows perf_event_{stop,read}() to observe the correct
2542 * ->oncpu if it sees ACTIVE.
2545 perf_event_set_state(event, PERF_EVENT_STATE_ACTIVE);
2548 * Unthrottle events, since we scheduled we might have missed several
2549 * ticks already, also for a heavily scheduling task there is little
2550 * guarantee it'll get a tick in a timely manner.
2552 if (unlikely(event->hw.interrupts == MAX_INTERRUPTS)) {
2553 perf_log_throttle(event, 1);
2554 event->hw.interrupts = 0;
2557 perf_pmu_disable(event->pmu);
2559 perf_set_shadow_time(event, ctx);
2561 perf_log_itrace_start(event);
2563 if (event->pmu->add(event, PERF_EF_START)) {
2564 perf_event_set_state(event, PERF_EVENT_STATE_INACTIVE);
2570 if (!is_software_event(event))
2571 cpuctx->active_oncpu++;
2572 if (!ctx->nr_active++)
2573 perf_event_ctx_activate(ctx);
2574 if (event->attr.freq && event->attr.sample_freq)
2577 if (event->attr.exclusive)
2578 cpuctx->exclusive = 1;
2581 perf_pmu_enable(event->pmu);
2587 group_sched_in(struct perf_event *group_event,
2588 struct perf_cpu_context *cpuctx,
2589 struct perf_event_context *ctx)
2591 struct perf_event *event, *partial_group = NULL;
2592 struct pmu *pmu = ctx->pmu;
2594 if (group_event->state == PERF_EVENT_STATE_OFF)
2597 pmu->start_txn(pmu, PERF_PMU_TXN_ADD);
2599 if (event_sched_in(group_event, cpuctx, ctx))
2603 * Schedule in siblings as one group (if any):
2605 for_each_sibling_event(event, group_event) {
2606 if (event_sched_in(event, cpuctx, ctx)) {
2607 partial_group = event;
2612 if (!pmu->commit_txn(pmu))
2617 * Groups can be scheduled in as one unit only, so undo any
2618 * partial group before returning:
2619 * The events up to the failed event are scheduled out normally.
2621 for_each_sibling_event(event, group_event) {
2622 if (event == partial_group)
2625 event_sched_out(event, cpuctx, ctx);
2627 event_sched_out(group_event, cpuctx, ctx);
2630 pmu->cancel_txn(pmu);
2635 * Work out whether we can put this event group on the CPU now.
2637 static int group_can_go_on(struct perf_event *event,
2638 struct perf_cpu_context *cpuctx,
2642 * Groups consisting entirely of software events can always go on.
2644 if (event->group_caps & PERF_EV_CAP_SOFTWARE)
2647 * If an exclusive group is already on, no other hardware
2650 if (cpuctx->exclusive)
2653 * If this group is exclusive and there are already
2654 * events on the CPU, it can't go on.
2656 if (event->attr.exclusive && !list_empty(get_event_list(event)))
2659 * Otherwise, try to add it if all previous groups were able
2665 static void add_event_to_ctx(struct perf_event *event,
2666 struct perf_event_context *ctx)
2668 list_add_event(event, ctx);
2669 perf_group_attach(event);
2672 static void ctx_sched_out(struct perf_event_context *ctx,
2673 struct perf_cpu_context *cpuctx,
2674 enum event_type_t event_type);
2676 ctx_sched_in(struct perf_event_context *ctx,
2677 struct perf_cpu_context *cpuctx,
2678 enum event_type_t event_type,
2679 struct task_struct *task);
2681 static void task_ctx_sched_out(struct perf_cpu_context *cpuctx,
2682 struct perf_event_context *ctx,
2683 enum event_type_t event_type)
2685 if (!cpuctx->task_ctx)
2688 if (WARN_ON_ONCE(ctx != cpuctx->task_ctx))
2691 ctx_sched_out(ctx, cpuctx, event_type);
2694 static void perf_event_sched_in(struct perf_cpu_context *cpuctx,
2695 struct perf_event_context *ctx,
2696 struct task_struct *task)
2698 cpu_ctx_sched_in(cpuctx, EVENT_PINNED, task);
2700 ctx_sched_in(ctx, cpuctx, EVENT_PINNED, task);
2701 cpu_ctx_sched_in(cpuctx, EVENT_FLEXIBLE, task);
2703 ctx_sched_in(ctx, cpuctx, EVENT_FLEXIBLE, task);
2707 * We want to maintain the following priority of scheduling:
2708 * - CPU pinned (EVENT_CPU | EVENT_PINNED)
2709 * - task pinned (EVENT_PINNED)
2710 * - CPU flexible (EVENT_CPU | EVENT_FLEXIBLE)
2711 * - task flexible (EVENT_FLEXIBLE).
2713 * In order to avoid unscheduling and scheduling back in everything every
2714 * time an event is added, only do it for the groups of equal priority and
2717 * This can be called after a batch operation on task events, in which case
2718 * event_type is a bit mask of the types of events involved. For CPU events,
2719 * event_type is only either EVENT_PINNED or EVENT_FLEXIBLE.
2721 static void ctx_resched(struct perf_cpu_context *cpuctx,
2722 struct perf_event_context *task_ctx,
2723 enum event_type_t event_type)
2725 enum event_type_t ctx_event_type;
2726 bool cpu_event = !!(event_type & EVENT_CPU);
2729 * If pinned groups are involved, flexible groups also need to be
2732 if (event_type & EVENT_PINNED)
2733 event_type |= EVENT_FLEXIBLE;
2735 ctx_event_type = event_type & EVENT_ALL;
2737 perf_pmu_disable(cpuctx->ctx.pmu);
2739 task_ctx_sched_out(cpuctx, task_ctx, event_type);
2742 * Decide which cpu ctx groups to schedule out based on the types
2743 * of events that caused rescheduling:
2744 * - EVENT_CPU: schedule out corresponding groups;
2745 * - EVENT_PINNED task events: schedule out EVENT_FLEXIBLE groups;
2746 * - otherwise, do nothing more.
2749 cpu_ctx_sched_out(cpuctx, ctx_event_type);
2750 else if (ctx_event_type & EVENT_PINNED)
2751 cpu_ctx_sched_out(cpuctx, EVENT_FLEXIBLE);
2753 perf_event_sched_in(cpuctx, task_ctx, current);
2754 perf_pmu_enable(cpuctx->ctx.pmu);
2757 void perf_pmu_resched(struct pmu *pmu)
2759 struct perf_cpu_context *cpuctx = this_cpu_ptr(pmu->pmu_cpu_context);
2760 struct perf_event_context *task_ctx = cpuctx->task_ctx;
2762 perf_ctx_lock(cpuctx, task_ctx);
2763 ctx_resched(cpuctx, task_ctx, EVENT_ALL|EVENT_CPU);
2764 perf_ctx_unlock(cpuctx, task_ctx);
2768 * Cross CPU call to install and enable a performance event
2770 * Very similar to remote_function() + event_function() but cannot assume that
2771 * things like ctx->is_active and cpuctx->task_ctx are set.
2773 static int __perf_install_in_context(void *info)
2775 struct perf_event *event = info;
2776 struct perf_event_context *ctx = event->ctx;
2777 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
2778 struct perf_event_context *task_ctx = cpuctx->task_ctx;
2779 bool reprogram = true;
2782 raw_spin_lock(&cpuctx->ctx.lock);
2784 raw_spin_lock(&ctx->lock);
2787 reprogram = (ctx->task == current);
2790 * If the task is running, it must be running on this CPU,
2791 * otherwise we cannot reprogram things.
2793 * If its not running, we don't care, ctx->lock will
2794 * serialize against it becoming runnable.
2796 if (task_curr(ctx->task) && !reprogram) {
2801 WARN_ON_ONCE(reprogram && cpuctx->task_ctx && cpuctx->task_ctx != ctx);
2802 } else if (task_ctx) {
2803 raw_spin_lock(&task_ctx->lock);
2806 #ifdef CONFIG_CGROUP_PERF
2807 if (event->state > PERF_EVENT_STATE_OFF && is_cgroup_event(event)) {
2809 * If the current cgroup doesn't match the event's
2810 * cgroup, we should not try to schedule it.
2812 struct perf_cgroup *cgrp = perf_cgroup_from_task(current, ctx);
2813 reprogram = cgroup_is_descendant(cgrp->css.cgroup,
2814 event->cgrp->css.cgroup);
2819 ctx_sched_out(ctx, cpuctx, EVENT_TIME);
2820 add_event_to_ctx(event, ctx);
2821 ctx_resched(cpuctx, task_ctx, get_event_type(event));
2823 add_event_to_ctx(event, ctx);
2827 perf_ctx_unlock(cpuctx, task_ctx);
2832 static bool exclusive_event_installable(struct perf_event *event,
2833 struct perf_event_context *ctx);
2836 * Attach a performance event to a context.
2838 * Very similar to event_function_call, see comment there.
2841 perf_install_in_context(struct perf_event_context *ctx,
2842 struct perf_event *event,
2845 struct task_struct *task = READ_ONCE(ctx->task);
2847 lockdep_assert_held(&ctx->mutex);
2849 WARN_ON_ONCE(!exclusive_event_installable(event, ctx));
2851 if (event->cpu != -1)
2855 * Ensures that if we can observe event->ctx, both the event and ctx
2856 * will be 'complete'. See perf_iterate_sb_cpu().
2858 smp_store_release(&event->ctx, ctx);
2861 * perf_event_attr::disabled events will not run and can be initialized
2862 * without IPI. Except when this is the first event for the context, in
2863 * that case we need the magic of the IPI to set ctx->is_active.
2865 * The IOC_ENABLE that is sure to follow the creation of a disabled
2866 * event will issue the IPI and reprogram the hardware.
2868 if (__perf_effective_state(event) == PERF_EVENT_STATE_OFF && ctx->nr_events) {
2869 raw_spin_lock_irq(&ctx->lock);
2870 if (ctx->task == TASK_TOMBSTONE) {
2871 raw_spin_unlock_irq(&ctx->lock);
2874 add_event_to_ctx(event, ctx);
2875 raw_spin_unlock_irq(&ctx->lock);
2880 cpu_function_call(cpu, __perf_install_in_context, event);
2885 * Should not happen, we validate the ctx is still alive before calling.
2887 if (WARN_ON_ONCE(task == TASK_TOMBSTONE))
2891 * Installing events is tricky because we cannot rely on ctx->is_active
2892 * to be set in case this is the nr_events 0 -> 1 transition.
2894 * Instead we use task_curr(), which tells us if the task is running.
2895 * However, since we use task_curr() outside of rq::lock, we can race
2896 * against the actual state. This means the result can be wrong.
2898 * If we get a false positive, we retry, this is harmless.
2900 * If we get a false negative, things are complicated. If we are after
2901 * perf_event_context_sched_in() ctx::lock will serialize us, and the
2902 * value must be correct. If we're before, it doesn't matter since
2903 * perf_event_context_sched_in() will program the counter.
2905 * However, this hinges on the remote context switch having observed
2906 * our task->perf_event_ctxp[] store, such that it will in fact take
2907 * ctx::lock in perf_event_context_sched_in().
2909 * We do this by task_function_call(), if the IPI fails to hit the task
2910 * we know any future context switch of task must see the
2911 * perf_event_ctpx[] store.
2915 * This smp_mb() orders the task->perf_event_ctxp[] store with the
2916 * task_cpu() load, such that if the IPI then does not find the task
2917 * running, a future context switch of that task must observe the
2922 if (!task_function_call(task, __perf_install_in_context, event))
2925 raw_spin_lock_irq(&ctx->lock);
2927 if (WARN_ON_ONCE(task == TASK_TOMBSTONE)) {
2929 * Cannot happen because we already checked above (which also
2930 * cannot happen), and we hold ctx->mutex, which serializes us
2931 * against perf_event_exit_task_context().
2933 raw_spin_unlock_irq(&ctx->lock);
2937 * If the task is not running, ctx->lock will avoid it becoming so,
2938 * thus we can safely install the event.
2940 if (task_curr(task)) {
2941 raw_spin_unlock_irq(&ctx->lock);
2944 add_event_to_ctx(event, ctx);
2945 raw_spin_unlock_irq(&ctx->lock);
2949 * Cross CPU call to enable a performance event
2951 static void __perf_event_enable(struct perf_event *event,
2952 struct perf_cpu_context *cpuctx,
2953 struct perf_event_context *ctx,
2956 struct perf_event *leader = event->group_leader;
2957 struct perf_event_context *task_ctx;
2959 if (event->state >= PERF_EVENT_STATE_INACTIVE ||
2960 event->state <= PERF_EVENT_STATE_ERROR)
2964 ctx_sched_out(ctx, cpuctx, EVENT_TIME);
2966 perf_event_set_state(event, PERF_EVENT_STATE_INACTIVE);
2967 perf_cgroup_event_enable(event, ctx);
2969 if (!ctx->is_active)
2972 if (!event_filter_match(event)) {
2973 ctx_sched_in(ctx, cpuctx, EVENT_TIME, current);
2978 * If the event is in a group and isn't the group leader,
2979 * then don't put it on unless the group is on.
2981 if (leader != event && leader->state != PERF_EVENT_STATE_ACTIVE) {
2982 ctx_sched_in(ctx, cpuctx, EVENT_TIME, current);
2986 task_ctx = cpuctx->task_ctx;
2988 WARN_ON_ONCE(task_ctx != ctx);
2990 ctx_resched(cpuctx, task_ctx, get_event_type(event));
2996 * If event->ctx is a cloned context, callers must make sure that
2997 * every task struct that event->ctx->task could possibly point to
2998 * remains valid. This condition is satisfied when called through
2999 * perf_event_for_each_child or perf_event_for_each as described
3000 * for perf_event_disable.
3002 static void _perf_event_enable(struct perf_event *event)
3004 struct perf_event_context *ctx = event->ctx;
3006 raw_spin_lock_irq(&ctx->lock);
3007 if (event->state >= PERF_EVENT_STATE_INACTIVE ||
3008 event->state < PERF_EVENT_STATE_ERROR) {
3010 raw_spin_unlock_irq(&ctx->lock);
3015 * If the event is in error state, clear that first.
3017 * That way, if we see the event in error state below, we know that it
3018 * has gone back into error state, as distinct from the task having
3019 * been scheduled away before the cross-call arrived.
3021 if (event->state == PERF_EVENT_STATE_ERROR) {
3023 * Detached SIBLING events cannot leave ERROR state.
3025 if (event->event_caps & PERF_EV_CAP_SIBLING &&
3026 event->group_leader == event)
3029 event->state = PERF_EVENT_STATE_OFF;
3031 raw_spin_unlock_irq(&ctx->lock);
3033 event_function_call(event, __perf_event_enable, NULL);
3037 * See perf_event_disable();
3039 void perf_event_enable(struct perf_event *event)
3041 struct perf_event_context *ctx;
3043 ctx = perf_event_ctx_lock(event);
3044 _perf_event_enable(event);
3045 perf_event_ctx_unlock(event, ctx);
3047 EXPORT_SYMBOL_GPL(perf_event_enable);
3049 struct stop_event_data {
3050 struct perf_event *event;
3051 unsigned int restart;
3054 static int __perf_event_stop(void *info)
3056 struct stop_event_data *sd = info;
3057 struct perf_event *event = sd->event;
3059 /* if it's already INACTIVE, do nothing */
3060 if (READ_ONCE(event->state) != PERF_EVENT_STATE_ACTIVE)
3063 /* matches smp_wmb() in event_sched_in() */
3067 * There is a window with interrupts enabled before we get here,
3068 * so we need to check again lest we try to stop another CPU's event.
3070 if (READ_ONCE(event->oncpu) != smp_processor_id())
3073 event->pmu->stop(event, PERF_EF_UPDATE);
3076 * May race with the actual stop (through perf_pmu_output_stop()),
3077 * but it is only used for events with AUX ring buffer, and such
3078 * events will refuse to restart because of rb::aux_mmap_count==0,
3079 * see comments in perf_aux_output_begin().
3081 * Since this is happening on an event-local CPU, no trace is lost
3085 event->pmu->start(event, 0);
3090 static int perf_event_stop(struct perf_event *event, int restart)
3092 struct stop_event_data sd = {
3099 if (READ_ONCE(event->state) != PERF_EVENT_STATE_ACTIVE)
3102 /* matches smp_wmb() in event_sched_in() */
3106 * We only want to restart ACTIVE events, so if the event goes
3107 * inactive here (event->oncpu==-1), there's nothing more to do;
3108 * fall through with ret==-ENXIO.
3110 ret = cpu_function_call(READ_ONCE(event->oncpu),
3111 __perf_event_stop, &sd);
3112 } while (ret == -EAGAIN);
3118 * In order to contain the amount of racy and tricky in the address filter
3119 * configuration management, it is a two part process:
3121 * (p1) when userspace mappings change as a result of (1) or (2) or (3) below,
3122 * we update the addresses of corresponding vmas in
3123 * event::addr_filter_ranges array and bump the event::addr_filters_gen;
3124 * (p2) when an event is scheduled in (pmu::add), it calls
3125 * perf_event_addr_filters_sync() which calls pmu::addr_filters_sync()
3126 * if the generation has changed since the previous call.
3128 * If (p1) happens while the event is active, we restart it to force (p2).
3130 * (1) perf_addr_filters_apply(): adjusting filters' offsets based on
3131 * pre-existing mappings, called once when new filters arrive via SET_FILTER
3133 * (2) perf_addr_filters_adjust(): adjusting filters' offsets based on newly
3134 * registered mapping, called for every new mmap(), with mm::mmap_lock down
3136 * (3) perf_event_addr_filters_exec(): clearing filters' offsets in the process
3139 void perf_event_addr_filters_sync(struct perf_event *event)
3141 struct perf_addr_filters_head *ifh = perf_event_addr_filters(event);
3143 if (!has_addr_filter(event))
3146 raw_spin_lock(&ifh->lock);
3147 if (event->addr_filters_gen != event->hw.addr_filters_gen) {
3148 event->pmu->addr_filters_sync(event);
3149 event->hw.addr_filters_gen = event->addr_filters_gen;
3151 raw_spin_unlock(&ifh->lock);
3153 EXPORT_SYMBOL_GPL(perf_event_addr_filters_sync);
3155 static int _perf_event_refresh(struct perf_event *event, int refresh)
3158 * not supported on inherited events
3160 if (event->attr.inherit || !is_sampling_event(event))
3163 atomic_add(refresh, &event->event_limit);
3164 _perf_event_enable(event);
3170 * See perf_event_disable()
3172 int perf_event_refresh(struct perf_event *event, int refresh)
3174 struct perf_event_context *ctx;
3177 ctx = perf_event_ctx_lock(event);
3178 ret = _perf_event_refresh(event, refresh);
3179 perf_event_ctx_unlock(event, ctx);
3183 EXPORT_SYMBOL_GPL(perf_event_refresh);
3185 static int perf_event_modify_breakpoint(struct perf_event *bp,
3186 struct perf_event_attr *attr)
3190 _perf_event_disable(bp);
3192 err = modify_user_hw_breakpoint_check(bp, attr, true);
3194 if (!bp->attr.disabled)
3195 _perf_event_enable(bp);
3200 static int perf_event_modify_attr(struct perf_event *event,
3201 struct perf_event_attr *attr)
3203 int (*func)(struct perf_event *, struct perf_event_attr *);
3204 struct perf_event *child;
3207 if (event->attr.type != attr->type)
3210 switch (event->attr.type) {
3211 case PERF_TYPE_BREAKPOINT:
3212 func = perf_event_modify_breakpoint;
3215 /* Place holder for future additions. */
3219 WARN_ON_ONCE(event->ctx->parent_ctx);
3221 mutex_lock(&event->child_mutex);
3222 err = func(event, attr);
3225 list_for_each_entry(child, &event->child_list, child_list) {
3226 err = func(child, attr);
3231 mutex_unlock(&event->child_mutex);
3235 static void ctx_sched_out(struct perf_event_context *ctx,
3236 struct perf_cpu_context *cpuctx,
3237 enum event_type_t event_type)
3239 struct perf_event *event, *tmp;
3240 int is_active = ctx->is_active;
3242 lockdep_assert_held(&ctx->lock);
3244 if (likely(!ctx->nr_events)) {
3246 * See __perf_remove_from_context().
3248 WARN_ON_ONCE(ctx->is_active);
3250 WARN_ON_ONCE(cpuctx->task_ctx);
3254 ctx->is_active &= ~event_type;
3255 if (!(ctx->is_active & EVENT_ALL))
3259 WARN_ON_ONCE(cpuctx->task_ctx != ctx);
3260 if (!ctx->is_active)
3261 cpuctx->task_ctx = NULL;
3265 * Always update time if it was set; not only when it changes.
3266 * Otherwise we can 'forget' to update time for any but the last
3267 * context we sched out. For example:
3269 * ctx_sched_out(.event_type = EVENT_FLEXIBLE)
3270 * ctx_sched_out(.event_type = EVENT_PINNED)
3272 * would only update time for the pinned events.
3274 if (is_active & EVENT_TIME) {
3275 /* update (and stop) ctx time */
3276 update_context_time(ctx);
3277 update_cgrp_time_from_cpuctx(cpuctx);
3280 is_active ^= ctx->is_active; /* changed bits */
3282 if (!ctx->nr_active || !(is_active & EVENT_ALL))
3285 perf_pmu_disable(ctx->pmu);
3286 if (is_active & EVENT_PINNED) {
3287 list_for_each_entry_safe(event, tmp, &ctx->pinned_active, active_list)
3288 group_sched_out(event, cpuctx, ctx);
3291 if (is_active & EVENT_FLEXIBLE) {
3292 list_for_each_entry_safe(event, tmp, &ctx->flexible_active, active_list)
3293 group_sched_out(event, cpuctx, ctx);
3296 * Since we cleared EVENT_FLEXIBLE, also clear
3297 * rotate_necessary, is will be reset by
3298 * ctx_flexible_sched_in() when needed.
3300 ctx->rotate_necessary = 0;
3302 perf_pmu_enable(ctx->pmu);
3306 * Test whether two contexts are equivalent, i.e. whether they have both been
3307 * cloned from the same version of the same context.
3309 * Equivalence is measured using a generation number in the context that is
3310 * incremented on each modification to it; see unclone_ctx(), list_add_event()
3311 * and list_del_event().
3313 static int context_equiv(struct perf_event_context *ctx1,
3314 struct perf_event_context *ctx2)
3316 lockdep_assert_held(&ctx1->lock);
3317 lockdep_assert_held(&ctx2->lock);
3319 /* Pinning disables the swap optimization */
3320 if (ctx1->pin_count || ctx2->pin_count)
3323 /* If ctx1 is the parent of ctx2 */
3324 if (ctx1 == ctx2->parent_ctx && ctx1->generation == ctx2->parent_gen)
3327 /* If ctx2 is the parent of ctx1 */
3328 if (ctx1->parent_ctx == ctx2 && ctx1->parent_gen == ctx2->generation)
3332 * If ctx1 and ctx2 have the same parent; we flatten the parent
3333 * hierarchy, see perf_event_init_context().
3335 if (ctx1->parent_ctx && ctx1->parent_ctx == ctx2->parent_ctx &&
3336 ctx1->parent_gen == ctx2->parent_gen)
3343 static void __perf_event_sync_stat(struct perf_event *event,
3344 struct perf_event *next_event)
3348 if (!event->attr.inherit_stat)
3352 * Update the event value, we cannot use perf_event_read()
3353 * because we're in the middle of a context switch and have IRQs
3354 * disabled, which upsets smp_call_function_single(), however
3355 * we know the event must be on the current CPU, therefore we
3356 * don't need to use it.
3358 if (event->state == PERF_EVENT_STATE_ACTIVE)
3359 event->pmu->read(event);
3361 perf_event_update_time(event);
3364 * In order to keep per-task stats reliable we need to flip the event
3365 * values when we flip the contexts.
3367 value = local64_read(&next_event->count);
3368 value = local64_xchg(&event->count, value);
3369 local64_set(&next_event->count, value);
3371 swap(event->total_time_enabled, next_event->total_time_enabled);
3372 swap(event->total_time_running, next_event->total_time_running);
3375 * Since we swizzled the values, update the user visible data too.
3377 perf_event_update_userpage(event);
3378 perf_event_update_userpage(next_event);
3381 static void perf_event_sync_stat(struct perf_event_context *ctx,
3382 struct perf_event_context *next_ctx)
3384 struct perf_event *event, *next_event;
3389 update_context_time(ctx);
3391 event = list_first_entry(&ctx->event_list,
3392 struct perf_event, event_entry);
3394 next_event = list_first_entry(&next_ctx->event_list,
3395 struct perf_event, event_entry);
3397 while (&event->event_entry != &ctx->event_list &&
3398 &next_event->event_entry != &next_ctx->event_list) {
3400 __perf_event_sync_stat(event, next_event);
3402 event = list_next_entry(event, event_entry);
3403 next_event = list_next_entry(next_event, event_entry);
3407 static void perf_event_context_sched_out(struct task_struct *task, int ctxn,
3408 struct task_struct *next)
3410 struct perf_event_context *ctx = task->perf_event_ctxp[ctxn];
3411 struct perf_event_context *next_ctx;
3412 struct perf_event_context *parent, *next_parent;
3413 struct perf_cpu_context *cpuctx;
3421 cpuctx = __get_cpu_context(ctx);
3422 if (!cpuctx->task_ctx)
3426 next_ctx = next->perf_event_ctxp[ctxn];
3430 parent = rcu_dereference(ctx->parent_ctx);
3431 next_parent = rcu_dereference(next_ctx->parent_ctx);
3433 /* If neither context have a parent context; they cannot be clones. */
3434 if (!parent && !next_parent)
3437 if (next_parent == ctx || next_ctx == parent || next_parent == parent) {
3439 * Looks like the two contexts are clones, so we might be
3440 * able to optimize the context switch. We lock both
3441 * contexts and check that they are clones under the
3442 * lock (including re-checking that neither has been
3443 * uncloned in the meantime). It doesn't matter which
3444 * order we take the locks because no other cpu could
3445 * be trying to lock both of these tasks.
3447 raw_spin_lock(&ctx->lock);
3448 raw_spin_lock_nested(&next_ctx->lock, SINGLE_DEPTH_NESTING);
3449 if (context_equiv(ctx, next_ctx)) {
3451 WRITE_ONCE(ctx->task, next);
3452 WRITE_ONCE(next_ctx->task, task);
3454 perf_pmu_disable(pmu);
3456 if (cpuctx->sched_cb_usage && pmu->sched_task)
3457 pmu->sched_task(ctx, false);
3460 * PMU specific parts of task perf context can require
3461 * additional synchronization. As an example of such
3462 * synchronization see implementation details of Intel
3463 * LBR call stack data profiling;
3465 if (pmu->swap_task_ctx)
3466 pmu->swap_task_ctx(ctx, next_ctx);
3468 swap(ctx->task_ctx_data, next_ctx->task_ctx_data);
3470 perf_pmu_enable(pmu);
3473 * RCU_INIT_POINTER here is safe because we've not
3474 * modified the ctx and the above modification of
3475 * ctx->task and ctx->task_ctx_data are immaterial
3476 * since those values are always verified under
3477 * ctx->lock which we're now holding.
3479 RCU_INIT_POINTER(task->perf_event_ctxp[ctxn], next_ctx);
3480 RCU_INIT_POINTER(next->perf_event_ctxp[ctxn], ctx);
3484 perf_event_sync_stat(ctx, next_ctx);
3486 raw_spin_unlock(&next_ctx->lock);
3487 raw_spin_unlock(&ctx->lock);
3493 raw_spin_lock(&ctx->lock);
3494 perf_pmu_disable(pmu);
3496 if (cpuctx->sched_cb_usage && pmu->sched_task)
3497 pmu->sched_task(ctx, false);
3498 task_ctx_sched_out(cpuctx, ctx, EVENT_ALL);
3500 perf_pmu_enable(pmu);
3501 raw_spin_unlock(&ctx->lock);
3505 static DEFINE_PER_CPU(struct list_head, sched_cb_list);
3507 void perf_sched_cb_dec(struct pmu *pmu)
3509 struct perf_cpu_context *cpuctx = this_cpu_ptr(pmu->pmu_cpu_context);
3511 this_cpu_dec(perf_sched_cb_usages);
3513 if (!--cpuctx->sched_cb_usage)
3514 list_del(&cpuctx->sched_cb_entry);
3518 void perf_sched_cb_inc(struct pmu *pmu)
3520 struct perf_cpu_context *cpuctx = this_cpu_ptr(pmu->pmu_cpu_context);
3522 if (!cpuctx->sched_cb_usage++)
3523 list_add(&cpuctx->sched_cb_entry, this_cpu_ptr(&sched_cb_list));
3525 this_cpu_inc(perf_sched_cb_usages);
3529 * This function provides the context switch callback to the lower code
3530 * layer. It is invoked ONLY when the context switch callback is enabled.
3532 * This callback is relevant even to per-cpu events; for example multi event
3533 * PEBS requires this to provide PID/TID information. This requires we flush
3534 * all queued PEBS records before we context switch to a new task.
3536 static void __perf_pmu_sched_task(struct perf_cpu_context *cpuctx, bool sched_in)
3540 pmu = cpuctx->ctx.pmu; /* software PMUs will not have sched_task */
3542 if (WARN_ON_ONCE(!pmu->sched_task))
3545 perf_ctx_lock(cpuctx, cpuctx->task_ctx);
3546 perf_pmu_disable(pmu);
3548 pmu->sched_task(cpuctx->task_ctx, sched_in);
3550 perf_pmu_enable(pmu);
3551 perf_ctx_unlock(cpuctx, cpuctx->task_ctx);
3554 static void perf_pmu_sched_task(struct task_struct *prev,
3555 struct task_struct *next,
3558 struct perf_cpu_context *cpuctx;
3563 list_for_each_entry(cpuctx, this_cpu_ptr(&sched_cb_list), sched_cb_entry) {
3564 /* will be handled in perf_event_context_sched_in/out */
3565 if (cpuctx->task_ctx)
3568 __perf_pmu_sched_task(cpuctx, sched_in);
3572 static void perf_event_switch(struct task_struct *task,
3573 struct task_struct *next_prev, bool sched_in);
3575 #define for_each_task_context_nr(ctxn) \
3576 for ((ctxn) = 0; (ctxn) < perf_nr_task_contexts; (ctxn)++)
3579 * Called from scheduler to remove the events of the current task,
3580 * with interrupts disabled.
3582 * We stop each event and update the event value in event->count.
3584 * This does not protect us against NMI, but disable()
3585 * sets the disabled bit in the control field of event _before_
3586 * accessing the event control register. If a NMI hits, then it will
3587 * not restart the event.
3589 void __perf_event_task_sched_out(struct task_struct *task,
3590 struct task_struct *next)
3594 if (__this_cpu_read(perf_sched_cb_usages))
3595 perf_pmu_sched_task(task, next, false);
3597 if (atomic_read(&nr_switch_events))
3598 perf_event_switch(task, next, false);
3600 for_each_task_context_nr(ctxn)
3601 perf_event_context_sched_out(task, ctxn, next);
3604 * if cgroup events exist on this CPU, then we need
3605 * to check if we have to switch out PMU state.
3606 * cgroup event are system-wide mode only
3608 if (atomic_read(this_cpu_ptr(&perf_cgroup_events)))
3609 perf_cgroup_sched_out(task, next);
3613 * Called with IRQs disabled
3615 static void cpu_ctx_sched_out(struct perf_cpu_context *cpuctx,
3616 enum event_type_t event_type)
3618 ctx_sched_out(&cpuctx->ctx, cpuctx, event_type);
3621 static bool perf_less_group_idx(const void *l, const void *r)
3623 const struct perf_event *le = *(const struct perf_event **)l;
3624 const struct perf_event *re = *(const struct perf_event **)r;
3626 return le->group_index < re->group_index;
3629 static void swap_ptr(void *l, void *r)
3631 void **lp = l, **rp = r;
3636 static const struct min_heap_callbacks perf_min_heap = {
3637 .elem_size = sizeof(struct perf_event *),
3638 .less = perf_less_group_idx,
3642 static void __heap_add(struct min_heap *heap, struct perf_event *event)
3644 struct perf_event **itrs = heap->data;
3647 itrs[heap->nr] = event;
3652 static noinline int visit_groups_merge(struct perf_cpu_context *cpuctx,
3653 struct perf_event_groups *groups, int cpu,
3654 int (*func)(struct perf_event *, void *),
3657 #ifdef CONFIG_CGROUP_PERF
3658 struct cgroup_subsys_state *css = NULL;
3660 /* Space for per CPU and/or any CPU event iterators. */
3661 struct perf_event *itrs[2];
3662 struct min_heap event_heap;
3663 struct perf_event **evt;
3667 event_heap = (struct min_heap){
3668 .data = cpuctx->heap,
3670 .size = cpuctx->heap_size,
3673 lockdep_assert_held(&cpuctx->ctx.lock);
3675 #ifdef CONFIG_CGROUP_PERF
3677 css = &cpuctx->cgrp->css;
3680 event_heap = (struct min_heap){
3683 .size = ARRAY_SIZE(itrs),
3685 /* Events not within a CPU context may be on any CPU. */
3686 __heap_add(&event_heap, perf_event_groups_first(groups, -1, NULL));
3688 evt = event_heap.data;
3690 __heap_add(&event_heap, perf_event_groups_first(groups, cpu, NULL));
3692 #ifdef CONFIG_CGROUP_PERF
3693 for (; css; css = css->parent)
3694 __heap_add(&event_heap, perf_event_groups_first(groups, cpu, css->cgroup));
3697 min_heapify_all(&event_heap, &perf_min_heap);
3699 while (event_heap.nr) {
3700 ret = func(*evt, data);
3704 *evt = perf_event_groups_next(*evt);
3706 min_heapify(&event_heap, 0, &perf_min_heap);
3708 min_heap_pop(&event_heap, &perf_min_heap);
3714 static inline bool event_update_userpage(struct perf_event *event)
3716 if (likely(!atomic_read(&event->mmap_count)))
3719 perf_event_update_time(event);
3720 perf_set_shadow_time(event, event->ctx);
3721 perf_event_update_userpage(event);
3726 static inline void group_update_userpage(struct perf_event *group_event)
3728 struct perf_event *event;
3730 if (!event_update_userpage(group_event))
3733 for_each_sibling_event(event, group_event)
3734 event_update_userpage(event);
3737 static int merge_sched_in(struct perf_event *event, void *data)
3739 struct perf_event_context *ctx = event->ctx;
3740 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
3741 int *can_add_hw = data;
3743 if (event->state <= PERF_EVENT_STATE_OFF)
3746 if (!event_filter_match(event))
3749 if (group_can_go_on(event, cpuctx, *can_add_hw)) {
3750 if (!group_sched_in(event, cpuctx, ctx))
3751 list_add_tail(&event->active_list, get_event_list(event));
3754 if (event->state == PERF_EVENT_STATE_INACTIVE) {
3756 if (event->attr.pinned) {
3757 perf_cgroup_event_disable(event, ctx);
3758 perf_event_set_state(event, PERF_EVENT_STATE_ERROR);
3760 ctx->rotate_necessary = 1;
3761 perf_mux_hrtimer_restart(cpuctx);
3762 group_update_userpage(event);
3770 ctx_pinned_sched_in(struct perf_event_context *ctx,
3771 struct perf_cpu_context *cpuctx)
3775 if (ctx != &cpuctx->ctx)
3778 visit_groups_merge(cpuctx, &ctx->pinned_groups,
3780 merge_sched_in, &can_add_hw);
3784 ctx_flexible_sched_in(struct perf_event_context *ctx,
3785 struct perf_cpu_context *cpuctx)
3789 if (ctx != &cpuctx->ctx)
3792 visit_groups_merge(cpuctx, &ctx->flexible_groups,
3794 merge_sched_in, &can_add_hw);
3798 ctx_sched_in(struct perf_event_context *ctx,
3799 struct perf_cpu_context *cpuctx,
3800 enum event_type_t event_type,
3801 struct task_struct *task)
3803 int is_active = ctx->is_active;
3806 lockdep_assert_held(&ctx->lock);
3808 if (likely(!ctx->nr_events))
3811 ctx->is_active |= (event_type | EVENT_TIME);
3814 cpuctx->task_ctx = ctx;
3816 WARN_ON_ONCE(cpuctx->task_ctx != ctx);
3819 is_active ^= ctx->is_active; /* changed bits */
3821 if (is_active & EVENT_TIME) {
3822 /* start ctx time */
3824 ctx->timestamp = now;
3825 perf_cgroup_set_timestamp(task, ctx);
3829 * First go through the list and put on any pinned groups
3830 * in order to give them the best chance of going on.
3832 if (is_active & EVENT_PINNED)
3833 ctx_pinned_sched_in(ctx, cpuctx);
3835 /* Then walk through the lower prio flexible groups */
3836 if (is_active & EVENT_FLEXIBLE)
3837 ctx_flexible_sched_in(ctx, cpuctx);
3840 static void cpu_ctx_sched_in(struct perf_cpu_context *cpuctx,
3841 enum event_type_t event_type,
3842 struct task_struct *task)
3844 struct perf_event_context *ctx = &cpuctx->ctx;
3846 ctx_sched_in(ctx, cpuctx, event_type, task);
3849 static void perf_event_context_sched_in(struct perf_event_context *ctx,
3850 struct task_struct *task)
3852 struct perf_cpu_context *cpuctx;
3855 cpuctx = __get_cpu_context(ctx);
3858 * HACK: for HETEROGENEOUS the task context might have switched to a
3859 * different PMU, force (re)set the context,
3861 pmu = ctx->pmu = cpuctx->ctx.pmu;
3863 if (cpuctx->task_ctx == ctx) {
3864 if (cpuctx->sched_cb_usage)
3865 __perf_pmu_sched_task(cpuctx, true);
3869 perf_ctx_lock(cpuctx, ctx);
3871 * We must check ctx->nr_events while holding ctx->lock, such
3872 * that we serialize against perf_install_in_context().
3874 if (!ctx->nr_events)
3877 perf_pmu_disable(pmu);
3879 * We want to keep the following priority order:
3880 * cpu pinned (that don't need to move), task pinned,
3881 * cpu flexible, task flexible.
3883 * However, if task's ctx is not carrying any pinned
3884 * events, no need to flip the cpuctx's events around.
3886 if (!RB_EMPTY_ROOT(&ctx->pinned_groups.tree))
3887 cpu_ctx_sched_out(cpuctx, EVENT_FLEXIBLE);
3888 perf_event_sched_in(cpuctx, ctx, task);
3890 if (cpuctx->sched_cb_usage && pmu->sched_task)
3891 pmu->sched_task(cpuctx->task_ctx, true);
3893 perf_pmu_enable(pmu);
3896 perf_ctx_unlock(cpuctx, ctx);
3900 * Called from scheduler to add the events of the current task
3901 * with interrupts disabled.
3903 * We restore the event value and then enable it.
3905 * This does not protect us against NMI, but enable()
3906 * sets the enabled bit in the control field of event _before_
3907 * accessing the event control register. If a NMI hits, then it will
3908 * keep the event running.
3910 void __perf_event_task_sched_in(struct task_struct *prev,
3911 struct task_struct *task)
3913 struct perf_event_context *ctx;
3917 * If cgroup events exist on this CPU, then we need to check if we have
3918 * to switch in PMU state; cgroup event are system-wide mode only.
3920 * Since cgroup events are CPU events, we must schedule these in before
3921 * we schedule in the task events.
3923 if (atomic_read(this_cpu_ptr(&perf_cgroup_events)))
3924 perf_cgroup_sched_in(prev, task);
3926 for_each_task_context_nr(ctxn) {
3927 ctx = task->perf_event_ctxp[ctxn];
3931 perf_event_context_sched_in(ctx, task);
3934 if (atomic_read(&nr_switch_events))
3935 perf_event_switch(task, prev, true);
3937 if (__this_cpu_read(perf_sched_cb_usages))
3938 perf_pmu_sched_task(prev, task, true);
3941 static u64 perf_calculate_period(struct perf_event *event, u64 nsec, u64 count)
3943 u64 frequency = event->attr.sample_freq;
3944 u64 sec = NSEC_PER_SEC;
3945 u64 divisor, dividend;
3947 int count_fls, nsec_fls, frequency_fls, sec_fls;
3949 count_fls = fls64(count);
3950 nsec_fls = fls64(nsec);
3951 frequency_fls = fls64(frequency);
3955 * We got @count in @nsec, with a target of sample_freq HZ
3956 * the target period becomes:
3959 * period = -------------------
3960 * @nsec * sample_freq
3965 * Reduce accuracy by one bit such that @a and @b converge
3966 * to a similar magnitude.
3968 #define REDUCE_FLS(a, b) \
3970 if (a##_fls > b##_fls) { \
3980 * Reduce accuracy until either term fits in a u64, then proceed with
3981 * the other, so that finally we can do a u64/u64 division.
3983 while (count_fls + sec_fls > 64 && nsec_fls + frequency_fls > 64) {
3984 REDUCE_FLS(nsec, frequency);
3985 REDUCE_FLS(sec, count);
3988 if (count_fls + sec_fls > 64) {
3989 divisor = nsec * frequency;
3991 while (count_fls + sec_fls > 64) {
3992 REDUCE_FLS(count, sec);
3996 dividend = count * sec;
3998 dividend = count * sec;
4000 while (nsec_fls + frequency_fls > 64) {
4001 REDUCE_FLS(nsec, frequency);
4005 divisor = nsec * frequency;
4011 return div64_u64(dividend, divisor);
4014 static DEFINE_PER_CPU(int, perf_throttled_count);
4015 static DEFINE_PER_CPU(u64, perf_throttled_seq);
4017 static void perf_adjust_period(struct perf_event *event, u64 nsec, u64 count, bool disable)
4019 struct hw_perf_event *hwc = &event->hw;
4020 s64 period, sample_period;
4023 period = perf_calculate_period(event, nsec, count);
4025 delta = (s64)(period - hwc->sample_period);
4026 delta = (delta + 7) / 8; /* low pass filter */
4028 sample_period = hwc->sample_period + delta;
4033 hwc->sample_period = sample_period;
4035 if (local64_read(&hwc->period_left) > 8*sample_period) {
4037 event->pmu->stop(event, PERF_EF_UPDATE);
4039 local64_set(&hwc->period_left, 0);
4042 event->pmu->start(event, PERF_EF_RELOAD);
4047 * combine freq adjustment with unthrottling to avoid two passes over the
4048 * events. At the same time, make sure, having freq events does not change
4049 * the rate of unthrottling as that would introduce bias.
4051 static void perf_adjust_freq_unthr_context(struct perf_event_context *ctx,
4054 struct perf_event *event;
4055 struct hw_perf_event *hwc;
4056 u64 now, period = TICK_NSEC;
4060 * only need to iterate over all events iff:
4061 * - context have events in frequency mode (needs freq adjust)
4062 * - there are events to unthrottle on this cpu
4064 if (!(ctx->nr_freq || needs_unthr))
4067 raw_spin_lock(&ctx->lock);
4068 perf_pmu_disable(ctx->pmu);
4070 list_for_each_entry_rcu(event, &ctx->event_list, event_entry) {
4071 if (event->state != PERF_EVENT_STATE_ACTIVE)
4074 if (!event_filter_match(event))
4077 perf_pmu_disable(event->pmu);
4081 if (hwc->interrupts == MAX_INTERRUPTS) {
4082 hwc->interrupts = 0;
4083 perf_log_throttle(event, 1);
4084 event->pmu->start(event, 0);
4087 if (!event->attr.freq || !event->attr.sample_freq)
4091 * stop the event and update event->count
4093 event->pmu->stop(event, PERF_EF_UPDATE);
4095 now = local64_read(&event->count);
4096 delta = now - hwc->freq_count_stamp;
4097 hwc->freq_count_stamp = now;
4101 * reload only if value has changed
4102 * we have stopped the event so tell that
4103 * to perf_adjust_period() to avoid stopping it
4107 perf_adjust_period(event, period, delta, false);
4109 event->pmu->start(event, delta > 0 ? PERF_EF_RELOAD : 0);
4111 perf_pmu_enable(event->pmu);
4114 perf_pmu_enable(ctx->pmu);
4115 raw_spin_unlock(&ctx->lock);
4119 * Move @event to the tail of the @ctx's elegible events.
4121 static void rotate_ctx(struct perf_event_context *ctx, struct perf_event *event)
4124 * Rotate the first entry last of non-pinned groups. Rotation might be
4125 * disabled by the inheritance code.
4127 if (ctx->rotate_disable)
4130 perf_event_groups_delete(&ctx->flexible_groups, event);
4131 perf_event_groups_insert(&ctx->flexible_groups, event);
4134 /* pick an event from the flexible_groups to rotate */
4135 static inline struct perf_event *
4136 ctx_event_to_rotate(struct perf_event_context *ctx)
4138 struct perf_event *event;
4140 /* pick the first active flexible event */
4141 event = list_first_entry_or_null(&ctx->flexible_active,
4142 struct perf_event, active_list);
4144 /* if no active flexible event, pick the first event */
4146 event = rb_entry_safe(rb_first(&ctx->flexible_groups.tree),
4147 typeof(*event), group_node);
4151 * Unconditionally clear rotate_necessary; if ctx_flexible_sched_in()
4152 * finds there are unschedulable events, it will set it again.
4154 ctx->rotate_necessary = 0;
4159 static bool perf_rotate_context(struct perf_cpu_context *cpuctx)
4161 struct perf_event *cpu_event = NULL, *task_event = NULL;
4162 struct perf_event_context *task_ctx = NULL;
4163 int cpu_rotate, task_rotate;
4166 * Since we run this from IRQ context, nobody can install new
4167 * events, thus the event count values are stable.
4170 cpu_rotate = cpuctx->ctx.rotate_necessary;
4171 task_ctx = cpuctx->task_ctx;
4172 task_rotate = task_ctx ? task_ctx->rotate_necessary : 0;
4174 if (!(cpu_rotate || task_rotate))
4177 perf_ctx_lock(cpuctx, cpuctx->task_ctx);
4178 perf_pmu_disable(cpuctx->ctx.pmu);
4181 task_event = ctx_event_to_rotate(task_ctx);
4183 cpu_event = ctx_event_to_rotate(&cpuctx->ctx);
4186 * As per the order given at ctx_resched() first 'pop' task flexible
4187 * and then, if needed CPU flexible.
4189 if (task_event || (task_ctx && cpu_event))
4190 ctx_sched_out(task_ctx, cpuctx, EVENT_FLEXIBLE);
4192 cpu_ctx_sched_out(cpuctx, EVENT_FLEXIBLE);
4195 rotate_ctx(task_ctx, task_event);
4197 rotate_ctx(&cpuctx->ctx, cpu_event);
4199 perf_event_sched_in(cpuctx, task_ctx, current);
4201 perf_pmu_enable(cpuctx->ctx.pmu);
4202 perf_ctx_unlock(cpuctx, cpuctx->task_ctx);
4207 void perf_event_task_tick(void)
4209 struct list_head *head = this_cpu_ptr(&active_ctx_list);
4210 struct perf_event_context *ctx, *tmp;
4213 lockdep_assert_irqs_disabled();
4215 __this_cpu_inc(perf_throttled_seq);
4216 throttled = __this_cpu_xchg(perf_throttled_count, 0);
4217 tick_dep_clear_cpu(smp_processor_id(), TICK_DEP_BIT_PERF_EVENTS);
4219 list_for_each_entry_safe(ctx, tmp, head, active_ctx_list)
4220 perf_adjust_freq_unthr_context(ctx, throttled);
4223 static int event_enable_on_exec(struct perf_event *event,
4224 struct perf_event_context *ctx)
4226 if (!event->attr.enable_on_exec)
4229 event->attr.enable_on_exec = 0;
4230 if (event->state >= PERF_EVENT_STATE_INACTIVE)
4233 perf_event_set_state(event, PERF_EVENT_STATE_INACTIVE);
4239 * Enable all of a task's events that have been marked enable-on-exec.
4240 * This expects task == current.
4242 static void perf_event_enable_on_exec(int ctxn)
4244 struct perf_event_context *ctx, *clone_ctx = NULL;
4245 enum event_type_t event_type = 0;
4246 struct perf_cpu_context *cpuctx;
4247 struct perf_event *event;
4248 unsigned long flags;
4251 local_irq_save(flags);
4252 ctx = current->perf_event_ctxp[ctxn];
4253 if (!ctx || !ctx->nr_events)
4256 cpuctx = __get_cpu_context(ctx);
4257 perf_ctx_lock(cpuctx, ctx);
4258 ctx_sched_out(ctx, cpuctx, EVENT_TIME);
4259 list_for_each_entry(event, &ctx->event_list, event_entry) {
4260 enabled |= event_enable_on_exec(event, ctx);
4261 event_type |= get_event_type(event);
4265 * Unclone and reschedule this context if we enabled any event.
4268 clone_ctx = unclone_ctx(ctx);
4269 ctx_resched(cpuctx, ctx, event_type);
4271 ctx_sched_in(ctx, cpuctx, EVENT_TIME, current);
4273 perf_ctx_unlock(cpuctx, ctx);
4276 local_irq_restore(flags);
4282 static void perf_remove_from_owner(struct perf_event *event);
4283 static void perf_event_exit_event(struct perf_event *event,
4284 struct perf_event_context *ctx);
4287 * Removes all events from the current task that have been marked
4288 * remove-on-exec, and feeds their values back to parent events.
4290 static void perf_event_remove_on_exec(int ctxn)
4292 struct perf_event_context *ctx, *clone_ctx = NULL;
4293 struct perf_event *event, *next;
4294 LIST_HEAD(free_list);
4295 unsigned long flags;
4296 bool modified = false;
4298 ctx = perf_pin_task_context(current, ctxn);
4302 mutex_lock(&ctx->mutex);
4304 if (WARN_ON_ONCE(ctx->task != current))
4307 list_for_each_entry_safe(event, next, &ctx->event_list, event_entry) {
4308 if (!event->attr.remove_on_exec)
4311 if (!is_kernel_event(event))
4312 perf_remove_from_owner(event);
4316 perf_event_exit_event(event, ctx);
4319 raw_spin_lock_irqsave(&ctx->lock, flags);
4321 clone_ctx = unclone_ctx(ctx);
4323 raw_spin_unlock_irqrestore(&ctx->lock, flags);
4326 mutex_unlock(&ctx->mutex);
4333 struct perf_read_data {
4334 struct perf_event *event;
4339 static int __perf_event_read_cpu(struct perf_event *event, int event_cpu)
4341 u16 local_pkg, event_pkg;
4343 if (event->group_caps & PERF_EV_CAP_READ_ACTIVE_PKG) {
4344 int local_cpu = smp_processor_id();
4346 event_pkg = topology_physical_package_id(event_cpu);
4347 local_pkg = topology_physical_package_id(local_cpu);
4349 if (event_pkg == local_pkg)
4357 * Cross CPU call to read the hardware event
4359 static void __perf_event_read(void *info)
4361 struct perf_read_data *data = info;
4362 struct perf_event *sub, *event = data->event;
4363 struct perf_event_context *ctx = event->ctx;
4364 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
4365 struct pmu *pmu = event->pmu;
4368 * If this is a task context, we need to check whether it is
4369 * the current task context of this cpu. If not it has been
4370 * scheduled out before the smp call arrived. In that case
4371 * event->count would have been updated to a recent sample
4372 * when the event was scheduled out.
4374 if (ctx->task && cpuctx->task_ctx != ctx)
4377 raw_spin_lock(&ctx->lock);
4378 if (ctx->is_active & EVENT_TIME) {
4379 update_context_time(ctx);
4380 update_cgrp_time_from_event(event);
4383 perf_event_update_time(event);
4385 perf_event_update_sibling_time(event);
4387 if (event->state != PERF_EVENT_STATE_ACTIVE)
4396 pmu->start_txn(pmu, PERF_PMU_TXN_READ);
4400 for_each_sibling_event(sub, event) {
4401 if (sub->state == PERF_EVENT_STATE_ACTIVE) {
4403 * Use sibling's PMU rather than @event's since
4404 * sibling could be on different (eg: software) PMU.
4406 sub->pmu->read(sub);
4410 data->ret = pmu->commit_txn(pmu);
4413 raw_spin_unlock(&ctx->lock);
4416 static inline u64 perf_event_count(struct perf_event *event)
4418 return local64_read(&event->count) + atomic64_read(&event->child_count);
4422 * NMI-safe method to read a local event, that is an event that
4424 * - either for the current task, or for this CPU
4425 * - does not have inherit set, for inherited task events
4426 * will not be local and we cannot read them atomically
4427 * - must not have a pmu::count method
4429 int perf_event_read_local(struct perf_event *event, u64 *value,
4430 u64 *enabled, u64 *running)
4432 unsigned long flags;
4436 * Disabling interrupts avoids all counter scheduling (context
4437 * switches, timer based rotation and IPIs).
4439 local_irq_save(flags);
4442 * It must not be an event with inherit set, we cannot read
4443 * all child counters from atomic context.
4445 if (event->attr.inherit) {
4450 /* If this is a per-task event, it must be for current */
4451 if ((event->attach_state & PERF_ATTACH_TASK) &&
4452 event->hw.target != current) {
4457 /* If this is a per-CPU event, it must be for this CPU */
4458 if (!(event->attach_state & PERF_ATTACH_TASK) &&
4459 event->cpu != smp_processor_id()) {
4464 /* If this is a pinned event it must be running on this CPU */
4465 if (event->attr.pinned && event->oncpu != smp_processor_id()) {
4471 * If the event is currently on this CPU, its either a per-task event,
4472 * or local to this CPU. Furthermore it means its ACTIVE (otherwise
4475 if (event->oncpu == smp_processor_id())
4476 event->pmu->read(event);
4478 *value = local64_read(&event->count);
4479 if (enabled || running) {
4480 u64 now = event->shadow_ctx_time + perf_clock();
4481 u64 __enabled, __running;
4483 __perf_update_times(event, now, &__enabled, &__running);
4485 *enabled = __enabled;
4487 *running = __running;
4490 local_irq_restore(flags);
4495 static int perf_event_read(struct perf_event *event, bool group)
4497 enum perf_event_state state = READ_ONCE(event->state);
4498 int event_cpu, ret = 0;
4501 * If event is enabled and currently active on a CPU, update the
4502 * value in the event structure:
4505 if (state == PERF_EVENT_STATE_ACTIVE) {
4506 struct perf_read_data data;
4509 * Orders the ->state and ->oncpu loads such that if we see
4510 * ACTIVE we must also see the right ->oncpu.
4512 * Matches the smp_wmb() from event_sched_in().
4516 event_cpu = READ_ONCE(event->oncpu);
4517 if ((unsigned)event_cpu >= nr_cpu_ids)
4520 data = (struct perf_read_data){
4527 event_cpu = __perf_event_read_cpu(event, event_cpu);
4530 * Purposely ignore the smp_call_function_single() return
4533 * If event_cpu isn't a valid CPU it means the event got
4534 * scheduled out and that will have updated the event count.
4536 * Therefore, either way, we'll have an up-to-date event count
4539 (void)smp_call_function_single(event_cpu, __perf_event_read, &data, 1);
4543 } else if (state == PERF_EVENT_STATE_INACTIVE) {
4544 struct perf_event_context *ctx = event->ctx;
4545 unsigned long flags;
4547 raw_spin_lock_irqsave(&ctx->lock, flags);
4548 state = event->state;
4549 if (state != PERF_EVENT_STATE_INACTIVE) {
4550 raw_spin_unlock_irqrestore(&ctx->lock, flags);
4555 * May read while context is not active (e.g., thread is
4556 * blocked), in that case we cannot update context time
4558 if (ctx->is_active & EVENT_TIME) {
4559 update_context_time(ctx);
4560 update_cgrp_time_from_event(event);
4563 perf_event_update_time(event);
4565 perf_event_update_sibling_time(event);
4566 raw_spin_unlock_irqrestore(&ctx->lock, flags);
4573 * Initialize the perf_event context in a task_struct:
4575 static void __perf_event_init_context(struct perf_event_context *ctx)
4577 raw_spin_lock_init(&ctx->lock);
4578 mutex_init(&ctx->mutex);
4579 INIT_LIST_HEAD(&ctx->active_ctx_list);
4580 perf_event_groups_init(&ctx->pinned_groups);
4581 perf_event_groups_init(&ctx->flexible_groups);
4582 INIT_LIST_HEAD(&ctx->event_list);
4583 INIT_LIST_HEAD(&ctx->pinned_active);
4584 INIT_LIST_HEAD(&ctx->flexible_active);
4585 refcount_set(&ctx->refcount, 1);
4588 static struct perf_event_context *
4589 alloc_perf_context(struct pmu *pmu, struct task_struct *task)
4591 struct perf_event_context *ctx;
4593 ctx = kzalloc(sizeof(struct perf_event_context), GFP_KERNEL);
4597 __perf_event_init_context(ctx);
4599 ctx->task = get_task_struct(task);
4605 static struct task_struct *
4606 find_lively_task_by_vpid(pid_t vpid)
4608 struct task_struct *task;
4614 task = find_task_by_vpid(vpid);
4616 get_task_struct(task);
4620 return ERR_PTR(-ESRCH);
4626 * Returns a matching context with refcount and pincount.
4628 static struct perf_event_context *
4629 find_get_context(struct pmu *pmu, struct task_struct *task,
4630 struct perf_event *event)
4632 struct perf_event_context *ctx, *clone_ctx = NULL;
4633 struct perf_cpu_context *cpuctx;
4634 void *task_ctx_data = NULL;
4635 unsigned long flags;
4637 int cpu = event->cpu;
4640 /* Must be root to operate on a CPU event: */
4641 err = perf_allow_cpu(&event->attr);
4643 return ERR_PTR(err);
4645 cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
4648 raw_spin_lock_irqsave(&ctx->lock, flags);
4650 raw_spin_unlock_irqrestore(&ctx->lock, flags);
4656 ctxn = pmu->task_ctx_nr;
4660 if (event->attach_state & PERF_ATTACH_TASK_DATA) {
4661 task_ctx_data = alloc_task_ctx_data(pmu);
4662 if (!task_ctx_data) {
4669 ctx = perf_lock_task_context(task, ctxn, &flags);
4671 clone_ctx = unclone_ctx(ctx);
4674 if (task_ctx_data && !ctx->task_ctx_data) {
4675 ctx->task_ctx_data = task_ctx_data;
4676 task_ctx_data = NULL;
4678 raw_spin_unlock_irqrestore(&ctx->lock, flags);
4683 ctx = alloc_perf_context(pmu, task);
4688 if (task_ctx_data) {
4689 ctx->task_ctx_data = task_ctx_data;
4690 task_ctx_data = NULL;
4694 mutex_lock(&task->perf_event_mutex);
4696 * If it has already passed perf_event_exit_task().
4697 * we must see PF_EXITING, it takes this mutex too.
4699 if (task->flags & PF_EXITING)
4701 else if (task->perf_event_ctxp[ctxn])
4706 rcu_assign_pointer(task->perf_event_ctxp[ctxn], ctx);
4708 mutex_unlock(&task->perf_event_mutex);
4710 if (unlikely(err)) {
4719 free_task_ctx_data(pmu, task_ctx_data);
4723 free_task_ctx_data(pmu, task_ctx_data);
4724 return ERR_PTR(err);
4727 static void perf_event_free_filter(struct perf_event *event);
4729 static void free_event_rcu(struct rcu_head *head)
4731 struct perf_event *event;
4733 event = container_of(head, struct perf_event, rcu_head);
4735 put_pid_ns(event->ns);
4736 perf_event_free_filter(event);
4737 kmem_cache_free(perf_event_cache, event);
4740 static void ring_buffer_attach(struct perf_event *event,
4741 struct perf_buffer *rb);
4743 static void detach_sb_event(struct perf_event *event)
4745 struct pmu_event_list *pel = per_cpu_ptr(&pmu_sb_events, event->cpu);
4747 raw_spin_lock(&pel->lock);
4748 list_del_rcu(&event->sb_list);
4749 raw_spin_unlock(&pel->lock);
4752 static bool is_sb_event(struct perf_event *event)
4754 struct perf_event_attr *attr = &event->attr;
4759 if (event->attach_state & PERF_ATTACH_TASK)
4762 if (attr->mmap || attr->mmap_data || attr->mmap2 ||
4763 attr->comm || attr->comm_exec ||
4764 attr->task || attr->ksymbol ||
4765 attr->context_switch || attr->text_poke ||
4771 static void unaccount_pmu_sb_event(struct perf_event *event)
4773 if (is_sb_event(event))
4774 detach_sb_event(event);
4777 static void unaccount_event_cpu(struct perf_event *event, int cpu)
4782 if (is_cgroup_event(event))
4783 atomic_dec(&per_cpu(perf_cgroup_events, cpu));
4786 #ifdef CONFIG_NO_HZ_FULL
4787 static DEFINE_SPINLOCK(nr_freq_lock);
4790 static void unaccount_freq_event_nohz(void)
4792 #ifdef CONFIG_NO_HZ_FULL
4793 spin_lock(&nr_freq_lock);
4794 if (atomic_dec_and_test(&nr_freq_events))
4795 tick_nohz_dep_clear(TICK_DEP_BIT_PERF_EVENTS);
4796 spin_unlock(&nr_freq_lock);
4800 static void unaccount_freq_event(void)
4802 if (tick_nohz_full_enabled())
4803 unaccount_freq_event_nohz();
4805 atomic_dec(&nr_freq_events);
4808 static void unaccount_event(struct perf_event *event)
4815 if (event->attach_state & (PERF_ATTACH_TASK | PERF_ATTACH_SCHED_CB))
4817 if (event->attr.mmap || event->attr.mmap_data)
4818 atomic_dec(&nr_mmap_events);
4819 if (event->attr.build_id)
4820 atomic_dec(&nr_build_id_events);
4821 if (event->attr.comm)
4822 atomic_dec(&nr_comm_events);
4823 if (event->attr.namespaces)
4824 atomic_dec(&nr_namespaces_events);
4825 if (event->attr.cgroup)
4826 atomic_dec(&nr_cgroup_events);
4827 if (event->attr.task)
4828 atomic_dec(&nr_task_events);
4829 if (event->attr.freq)
4830 unaccount_freq_event();
4831 if (event->attr.context_switch) {
4833 atomic_dec(&nr_switch_events);
4835 if (is_cgroup_event(event))
4837 if (has_branch_stack(event))
4839 if (event->attr.ksymbol)
4840 atomic_dec(&nr_ksymbol_events);
4841 if (event->attr.bpf_event)
4842 atomic_dec(&nr_bpf_events);
4843 if (event->attr.text_poke)
4844 atomic_dec(&nr_text_poke_events);
4847 if (!atomic_add_unless(&perf_sched_count, -1, 1))
4848 schedule_delayed_work(&perf_sched_work, HZ);
4851 unaccount_event_cpu(event, event->cpu);
4853 unaccount_pmu_sb_event(event);
4856 static void perf_sched_delayed(struct work_struct *work)
4858 mutex_lock(&perf_sched_mutex);
4859 if (atomic_dec_and_test(&perf_sched_count))
4860 static_branch_disable(&perf_sched_events);
4861 mutex_unlock(&perf_sched_mutex);
4865 * The following implement mutual exclusion of events on "exclusive" pmus
4866 * (PERF_PMU_CAP_EXCLUSIVE). Such pmus can only have one event scheduled
4867 * at a time, so we disallow creating events that might conflict, namely:
4869 * 1) cpu-wide events in the presence of per-task events,
4870 * 2) per-task events in the presence of cpu-wide events,
4871 * 3) two matching events on the same context.
4873 * The former two cases are handled in the allocation path (perf_event_alloc(),
4874 * _free_event()), the latter -- before the first perf_install_in_context().
4876 static int exclusive_event_init(struct perf_event *event)
4878 struct pmu *pmu = event->pmu;
4880 if (!is_exclusive_pmu(pmu))
4884 * Prevent co-existence of per-task and cpu-wide events on the
4885 * same exclusive pmu.
4887 * Negative pmu::exclusive_cnt means there are cpu-wide
4888 * events on this "exclusive" pmu, positive means there are
4891 * Since this is called in perf_event_alloc() path, event::ctx
4892 * doesn't exist yet; it is, however, safe to use PERF_ATTACH_TASK
4893 * to mean "per-task event", because unlike other attach states it
4894 * never gets cleared.
4896 if (event->attach_state & PERF_ATTACH_TASK) {
4897 if (!atomic_inc_unless_negative(&pmu->exclusive_cnt))
4900 if (!atomic_dec_unless_positive(&pmu->exclusive_cnt))
4907 static void exclusive_event_destroy(struct perf_event *event)
4909 struct pmu *pmu = event->pmu;
4911 if (!is_exclusive_pmu(pmu))
4914 /* see comment in exclusive_event_init() */
4915 if (event->attach_state & PERF_ATTACH_TASK)
4916 atomic_dec(&pmu->exclusive_cnt);
4918 atomic_inc(&pmu->exclusive_cnt);
4921 static bool exclusive_event_match(struct perf_event *e1, struct perf_event *e2)
4923 if ((e1->pmu == e2->pmu) &&
4924 (e1->cpu == e2->cpu ||
4931 static bool exclusive_event_installable(struct perf_event *event,
4932 struct perf_event_context *ctx)
4934 struct perf_event *iter_event;
4935 struct pmu *pmu = event->pmu;
4937 lockdep_assert_held(&ctx->mutex);
4939 if (!is_exclusive_pmu(pmu))
4942 list_for_each_entry(iter_event, &ctx->event_list, event_entry) {
4943 if (exclusive_event_match(iter_event, event))
4950 static void perf_addr_filters_splice(struct perf_event *event,
4951 struct list_head *head);
4953 static void _free_event(struct perf_event *event)
4955 irq_work_sync(&event->pending);
4957 unaccount_event(event);
4959 security_perf_event_free(event);
4963 * Can happen when we close an event with re-directed output.
4965 * Since we have a 0 refcount, perf_mmap_close() will skip
4966 * over us; possibly making our ring_buffer_put() the last.
4968 mutex_lock(&event->mmap_mutex);
4969 ring_buffer_attach(event, NULL);
4970 mutex_unlock(&event->mmap_mutex);
4973 if (is_cgroup_event(event))
4974 perf_detach_cgroup(event);
4976 if (!event->parent) {
4977 if (event->attr.sample_type & PERF_SAMPLE_CALLCHAIN)
4978 put_callchain_buffers();
4981 perf_event_free_bpf_prog(event);
4982 perf_addr_filters_splice(event, NULL);
4983 kfree(event->addr_filter_ranges);
4986 event->destroy(event);
4989 * Must be after ->destroy(), due to uprobe_perf_close() using
4992 if (event->hw.target)
4993 put_task_struct(event->hw.target);
4996 * perf_event_free_task() relies on put_ctx() being 'last', in particular
4997 * all task references must be cleaned up.
5000 put_ctx(event->ctx);
5002 exclusive_event_destroy(event);
5003 module_put(event->pmu->module);
5005 call_rcu(&event->rcu_head, free_event_rcu);
5009 * Used to free events which have a known refcount of 1, such as in error paths
5010 * where the event isn't exposed yet and inherited events.
5012 static void free_event(struct perf_event *event)
5014 if (WARN(atomic_long_cmpxchg(&event->refcount, 1, 0) != 1,
5015 "unexpected event refcount: %ld; ptr=%p\n",
5016 atomic_long_read(&event->refcount), event)) {
5017 /* leak to avoid use-after-free */
5025 * Remove user event from the owner task.
5027 static void perf_remove_from_owner(struct perf_event *event)
5029 struct task_struct *owner;
5033 * Matches the smp_store_release() in perf_event_exit_task(). If we
5034 * observe !owner it means the list deletion is complete and we can
5035 * indeed free this event, otherwise we need to serialize on
5036 * owner->perf_event_mutex.
5038 owner = READ_ONCE(event->owner);
5041 * Since delayed_put_task_struct() also drops the last
5042 * task reference we can safely take a new reference
5043 * while holding the rcu_read_lock().
5045 get_task_struct(owner);
5051 * If we're here through perf_event_exit_task() we're already
5052 * holding ctx->mutex which would be an inversion wrt. the
5053 * normal lock order.
5055 * However we can safely take this lock because its the child
5058 mutex_lock_nested(&owner->perf_event_mutex, SINGLE_DEPTH_NESTING);
5061 * We have to re-check the event->owner field, if it is cleared
5062 * we raced with perf_event_exit_task(), acquiring the mutex
5063 * ensured they're done, and we can proceed with freeing the
5067 list_del_init(&event->owner_entry);
5068 smp_store_release(&event->owner, NULL);
5070 mutex_unlock(&owner->perf_event_mutex);
5071 put_task_struct(owner);
5075 static void put_event(struct perf_event *event)
5077 if (!atomic_long_dec_and_test(&event->refcount))
5084 * Kill an event dead; while event:refcount will preserve the event
5085 * object, it will not preserve its functionality. Once the last 'user'
5086 * gives up the object, we'll destroy the thing.
5088 int perf_event_release_kernel(struct perf_event *event)
5090 struct perf_event_context *ctx = event->ctx;
5091 struct perf_event *child, *tmp;
5092 LIST_HEAD(free_list);
5095 * If we got here through err_file: fput(event_file); we will not have
5096 * attached to a context yet.
5099 WARN_ON_ONCE(event->attach_state &
5100 (PERF_ATTACH_CONTEXT|PERF_ATTACH_GROUP));
5104 if (!is_kernel_event(event))
5105 perf_remove_from_owner(event);
5107 ctx = perf_event_ctx_lock(event);
5108 WARN_ON_ONCE(ctx->parent_ctx);
5109 perf_remove_from_context(event, DETACH_GROUP);
5111 raw_spin_lock_irq(&ctx->lock);
5113 * Mark this event as STATE_DEAD, there is no external reference to it
5116 * Anybody acquiring event->child_mutex after the below loop _must_
5117 * also see this, most importantly inherit_event() which will avoid
5118 * placing more children on the list.
5120 * Thus this guarantees that we will in fact observe and kill _ALL_
5123 event->state = PERF_EVENT_STATE_DEAD;
5124 raw_spin_unlock_irq(&ctx->lock);
5126 perf_event_ctx_unlock(event, ctx);
5129 mutex_lock(&event->child_mutex);
5130 list_for_each_entry(child, &event->child_list, child_list) {
5133 * Cannot change, child events are not migrated, see the
5134 * comment with perf_event_ctx_lock_nested().
5136 ctx = READ_ONCE(child->ctx);
5138 * Since child_mutex nests inside ctx::mutex, we must jump
5139 * through hoops. We start by grabbing a reference on the ctx.
5141 * Since the event cannot get freed while we hold the
5142 * child_mutex, the context must also exist and have a !0
5148 * Now that we have a ctx ref, we can drop child_mutex, and
5149 * acquire ctx::mutex without fear of it going away. Then we
5150 * can re-acquire child_mutex.
5152 mutex_unlock(&event->child_mutex);
5153 mutex_lock(&ctx->mutex);
5154 mutex_lock(&event->child_mutex);
5157 * Now that we hold ctx::mutex and child_mutex, revalidate our
5158 * state, if child is still the first entry, it didn't get freed
5159 * and we can continue doing so.
5161 tmp = list_first_entry_or_null(&event->child_list,
5162 struct perf_event, child_list);
5164 perf_remove_from_context(child, DETACH_GROUP);
5165 list_move(&child->child_list, &free_list);
5167 * This matches the refcount bump in inherit_event();
5168 * this can't be the last reference.
5173 mutex_unlock(&event->child_mutex);
5174 mutex_unlock(&ctx->mutex);
5178 mutex_unlock(&event->child_mutex);
5180 list_for_each_entry_safe(child, tmp, &free_list, child_list) {
5181 void *var = &child->ctx->refcount;
5183 list_del(&child->child_list);
5187 * Wake any perf_event_free_task() waiting for this event to be
5190 smp_mb(); /* pairs with wait_var_event() */
5195 put_event(event); /* Must be the 'last' reference */
5198 EXPORT_SYMBOL_GPL(perf_event_release_kernel);
5201 * Called when the last reference to the file is gone.
5203 static int perf_release(struct inode *inode, struct file *file)
5205 perf_event_release_kernel(file->private_data);
5209 static u64 __perf_event_read_value(struct perf_event *event, u64 *enabled, u64 *running)
5211 struct perf_event *child;
5217 mutex_lock(&event->child_mutex);
5219 (void)perf_event_read(event, false);
5220 total += perf_event_count(event);
5222 *enabled += event->total_time_enabled +
5223 atomic64_read(&event->child_total_time_enabled);
5224 *running += event->total_time_running +
5225 atomic64_read(&event->child_total_time_running);
5227 list_for_each_entry(child, &event->child_list, child_list) {
5228 (void)perf_event_read(child, false);
5229 total += perf_event_count(child);
5230 *enabled += child->total_time_enabled;
5231 *running += child->total_time_running;
5233 mutex_unlock(&event->child_mutex);
5238 u64 perf_event_read_value(struct perf_event *event, u64 *enabled, u64 *running)
5240 struct perf_event_context *ctx;
5243 ctx = perf_event_ctx_lock(event);
5244 count = __perf_event_read_value(event, enabled, running);
5245 perf_event_ctx_unlock(event, ctx);
5249 EXPORT_SYMBOL_GPL(perf_event_read_value);
5251 static int __perf_read_group_add(struct perf_event *leader,
5252 u64 read_format, u64 *values)
5254 struct perf_event_context *ctx = leader->ctx;
5255 struct perf_event *sub;
5256 unsigned long flags;
5257 int n = 1; /* skip @nr */
5260 ret = perf_event_read(leader, true);
5264 raw_spin_lock_irqsave(&ctx->lock, flags);
5267 * Since we co-schedule groups, {enabled,running} times of siblings
5268 * will be identical to those of the leader, so we only publish one
5271 if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED) {
5272 values[n++] += leader->total_time_enabled +
5273 atomic64_read(&leader->child_total_time_enabled);
5276 if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING) {
5277 values[n++] += leader->total_time_running +
5278 atomic64_read(&leader->child_total_time_running);
5282 * Write {count,id} tuples for every sibling.
5284 values[n++] += perf_event_count(leader);
5285 if (read_format & PERF_FORMAT_ID)
5286 values[n++] = primary_event_id(leader);
5288 for_each_sibling_event(sub, leader) {
5289 values[n++] += perf_event_count(sub);
5290 if (read_format & PERF_FORMAT_ID)
5291 values[n++] = primary_event_id(sub);
5294 raw_spin_unlock_irqrestore(&ctx->lock, flags);
5298 static int perf_read_group(struct perf_event *event,
5299 u64 read_format, char __user *buf)
5301 struct perf_event *leader = event->group_leader, *child;
5302 struct perf_event_context *ctx = leader->ctx;
5306 lockdep_assert_held(&ctx->mutex);
5308 values = kzalloc(event->read_size, GFP_KERNEL);
5312 values[0] = 1 + leader->nr_siblings;
5315 * By locking the child_mutex of the leader we effectively
5316 * lock the child list of all siblings.. XXX explain how.
5318 mutex_lock(&leader->child_mutex);
5320 ret = __perf_read_group_add(leader, read_format, values);
5324 list_for_each_entry(child, &leader->child_list, child_list) {
5325 ret = __perf_read_group_add(child, read_format, values);
5330 mutex_unlock(&leader->child_mutex);
5332 ret = event->read_size;
5333 if (copy_to_user(buf, values, event->read_size))
5338 mutex_unlock(&leader->child_mutex);
5344 static int perf_read_one(struct perf_event *event,
5345 u64 read_format, char __user *buf)
5347 u64 enabled, running;
5351 values[n++] = __perf_event_read_value(event, &enabled, &running);
5352 if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED)
5353 values[n++] = enabled;
5354 if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING)
5355 values[n++] = running;
5356 if (read_format & PERF_FORMAT_ID)
5357 values[n++] = primary_event_id(event);
5359 if (copy_to_user(buf, values, n * sizeof(u64)))
5362 return n * sizeof(u64);
5365 static bool is_event_hup(struct perf_event *event)
5369 if (event->state > PERF_EVENT_STATE_EXIT)
5372 mutex_lock(&event->child_mutex);
5373 no_children = list_empty(&event->child_list);
5374 mutex_unlock(&event->child_mutex);
5379 * Read the performance event - simple non blocking version for now
5382 __perf_read(struct perf_event *event, char __user *buf, size_t count)
5384 u64 read_format = event->attr.read_format;
5388 * Return end-of-file for a read on an event that is in
5389 * error state (i.e. because it was pinned but it couldn't be
5390 * scheduled on to the CPU at some point).
5392 if (event->state == PERF_EVENT_STATE_ERROR)
5395 if (count < event->read_size)
5398 WARN_ON_ONCE(event->ctx->parent_ctx);
5399 if (read_format & PERF_FORMAT_GROUP)
5400 ret = perf_read_group(event, read_format, buf);
5402 ret = perf_read_one(event, read_format, buf);
5408 perf_read(struct file *file, char __user *buf, size_t count, loff_t *ppos)
5410 struct perf_event *event = file->private_data;
5411 struct perf_event_context *ctx;
5414 ret = security_perf_event_read(event);
5418 ctx = perf_event_ctx_lock(event);
5419 ret = __perf_read(event, buf, count);
5420 perf_event_ctx_unlock(event, ctx);
5425 static __poll_t perf_poll(struct file *file, poll_table *wait)
5427 struct perf_event *event = file->private_data;
5428 struct perf_buffer *rb;
5429 __poll_t events = EPOLLHUP;
5431 poll_wait(file, &event->waitq, wait);
5433 if (is_event_hup(event))
5437 * Pin the event->rb by taking event->mmap_mutex; otherwise
5438 * perf_event_set_output() can swizzle our rb and make us miss wakeups.
5440 mutex_lock(&event->mmap_mutex);
5443 events = atomic_xchg(&rb->poll, 0);
5444 mutex_unlock(&event->mmap_mutex);
5448 static void _perf_event_reset(struct perf_event *event)
5450 (void)perf_event_read(event, false);
5451 local64_set(&event->count, 0);
5452 perf_event_update_userpage(event);
5455 /* Assume it's not an event with inherit set. */
5456 u64 perf_event_pause(struct perf_event *event, bool reset)
5458 struct perf_event_context *ctx;
5461 ctx = perf_event_ctx_lock(event);
5462 WARN_ON_ONCE(event->attr.inherit);
5463 _perf_event_disable(event);
5464 count = local64_read(&event->count);
5466 local64_set(&event->count, 0);
5467 perf_event_ctx_unlock(event, ctx);
5471 EXPORT_SYMBOL_GPL(perf_event_pause);
5474 * Holding the top-level event's child_mutex means that any
5475 * descendant process that has inherited this event will block
5476 * in perf_event_exit_event() if it goes to exit, thus satisfying the
5477 * task existence requirements of perf_event_enable/disable.
5479 static void perf_event_for_each_child(struct perf_event *event,
5480 void (*func)(struct perf_event *))
5482 struct perf_event *child;
5484 WARN_ON_ONCE(event->ctx->parent_ctx);
5486 mutex_lock(&event->child_mutex);
5488 list_for_each_entry(child, &event->child_list, child_list)
5490 mutex_unlock(&event->child_mutex);
5493 static void perf_event_for_each(struct perf_event *event,
5494 void (*func)(struct perf_event *))
5496 struct perf_event_context *ctx = event->ctx;
5497 struct perf_event *sibling;
5499 lockdep_assert_held(&ctx->mutex);
5501 event = event->group_leader;
5503 perf_event_for_each_child(event, func);
5504 for_each_sibling_event(sibling, event)
5505 perf_event_for_each_child(sibling, func);
5508 static void __perf_event_period(struct perf_event *event,
5509 struct perf_cpu_context *cpuctx,
5510 struct perf_event_context *ctx,
5513 u64 value = *((u64 *)info);
5516 if (event->attr.freq) {
5517 event->attr.sample_freq = value;
5519 event->attr.sample_period = value;
5520 event->hw.sample_period = value;
5523 active = (event->state == PERF_EVENT_STATE_ACTIVE);
5525 perf_pmu_disable(ctx->pmu);
5527 * We could be throttled; unthrottle now to avoid the tick
5528 * trying to unthrottle while we already re-started the event.
5530 if (event->hw.interrupts == MAX_INTERRUPTS) {
5531 event->hw.interrupts = 0;
5532 perf_log_throttle(event, 1);
5534 event->pmu->stop(event, PERF_EF_UPDATE);
5537 local64_set(&event->hw.period_left, 0);
5540 event->pmu->start(event, PERF_EF_RELOAD);
5541 perf_pmu_enable(ctx->pmu);
5545 static int perf_event_check_period(struct perf_event *event, u64 value)
5547 return event->pmu->check_period(event, value);
5550 static int _perf_event_period(struct perf_event *event, u64 value)
5552 if (!is_sampling_event(event))
5558 if (event->attr.freq && value > sysctl_perf_event_sample_rate)
5561 if (perf_event_check_period(event, value))
5564 if (!event->attr.freq && (value & (1ULL << 63)))
5567 event_function_call(event, __perf_event_period, &value);
5572 int perf_event_period(struct perf_event *event, u64 value)
5574 struct perf_event_context *ctx;
5577 ctx = perf_event_ctx_lock(event);
5578 ret = _perf_event_period(event, value);
5579 perf_event_ctx_unlock(event, ctx);
5583 EXPORT_SYMBOL_GPL(perf_event_period);
5585 static const struct file_operations perf_fops;
5587 static inline int perf_fget_light(int fd, struct fd *p)
5589 struct fd f = fdget(fd);
5593 if (f.file->f_op != &perf_fops) {
5601 static int perf_event_set_output(struct perf_event *event,
5602 struct perf_event *output_event);
5603 static int perf_event_set_filter(struct perf_event *event, void __user *arg);
5604 static int perf_copy_attr(struct perf_event_attr __user *uattr,
5605 struct perf_event_attr *attr);
5607 static long _perf_ioctl(struct perf_event *event, unsigned int cmd, unsigned long arg)
5609 void (*func)(struct perf_event *);
5613 case PERF_EVENT_IOC_ENABLE:
5614 func = _perf_event_enable;
5616 case PERF_EVENT_IOC_DISABLE:
5617 func = _perf_event_disable;
5619 case PERF_EVENT_IOC_RESET:
5620 func = _perf_event_reset;
5623 case PERF_EVENT_IOC_REFRESH:
5624 return _perf_event_refresh(event, arg);
5626 case PERF_EVENT_IOC_PERIOD:
5630 if (copy_from_user(&value, (u64 __user *)arg, sizeof(value)))
5633 return _perf_event_period(event, value);
5635 case PERF_EVENT_IOC_ID:
5637 u64 id = primary_event_id(event);
5639 if (copy_to_user((void __user *)arg, &id, sizeof(id)))
5644 case PERF_EVENT_IOC_SET_OUTPUT:
5648 struct perf_event *output_event;
5650 ret = perf_fget_light(arg, &output);
5653 output_event = output.file->private_data;
5654 ret = perf_event_set_output(event, output_event);
5657 ret = perf_event_set_output(event, NULL);
5662 case PERF_EVENT_IOC_SET_FILTER:
5663 return perf_event_set_filter(event, (void __user *)arg);
5665 case PERF_EVENT_IOC_SET_BPF:
5667 struct bpf_prog *prog;
5670 prog = bpf_prog_get(arg);
5672 return PTR_ERR(prog);
5674 err = perf_event_set_bpf_prog(event, prog, 0);
5683 case PERF_EVENT_IOC_PAUSE_OUTPUT: {
5684 struct perf_buffer *rb;
5687 rb = rcu_dereference(event->rb);
5688 if (!rb || !rb->nr_pages) {
5692 rb_toggle_paused(rb, !!arg);
5697 case PERF_EVENT_IOC_QUERY_BPF:
5698 return perf_event_query_prog_array(event, (void __user *)arg);
5700 case PERF_EVENT_IOC_MODIFY_ATTRIBUTES: {
5701 struct perf_event_attr new_attr;
5702 int err = perf_copy_attr((struct perf_event_attr __user *)arg,
5708 return perf_event_modify_attr(event, &new_attr);
5714 if (flags & PERF_IOC_FLAG_GROUP)
5715 perf_event_for_each(event, func);
5717 perf_event_for_each_child(event, func);
5722 static long perf_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
5724 struct perf_event *event = file->private_data;
5725 struct perf_event_context *ctx;
5728 /* Treat ioctl like writes as it is likely a mutating operation. */
5729 ret = security_perf_event_write(event);
5733 ctx = perf_event_ctx_lock(event);
5734 ret = _perf_ioctl(event, cmd, arg);
5735 perf_event_ctx_unlock(event, ctx);
5740 #ifdef CONFIG_COMPAT
5741 static long perf_compat_ioctl(struct file *file, unsigned int cmd,
5744 switch (_IOC_NR(cmd)) {
5745 case _IOC_NR(PERF_EVENT_IOC_SET_FILTER):
5746 case _IOC_NR(PERF_EVENT_IOC_ID):
5747 case _IOC_NR(PERF_EVENT_IOC_QUERY_BPF):
5748 case _IOC_NR(PERF_EVENT_IOC_MODIFY_ATTRIBUTES):
5749 /* Fix up pointer size (usually 4 -> 8 in 32-on-64-bit case */
5750 if (_IOC_SIZE(cmd) == sizeof(compat_uptr_t)) {
5751 cmd &= ~IOCSIZE_MASK;
5752 cmd |= sizeof(void *) << IOCSIZE_SHIFT;
5756 return perf_ioctl(file, cmd, arg);
5759 # define perf_compat_ioctl NULL
5762 int perf_event_task_enable(void)
5764 struct perf_event_context *ctx;
5765 struct perf_event *event;
5767 mutex_lock(¤t->perf_event_mutex);
5768 list_for_each_entry(event, ¤t->perf_event_list, owner_entry) {
5769 ctx = perf_event_ctx_lock(event);
5770 perf_event_for_each_child(event, _perf_event_enable);
5771 perf_event_ctx_unlock(event, ctx);
5773 mutex_unlock(¤t->perf_event_mutex);
5778 int perf_event_task_disable(void)
5780 struct perf_event_context *ctx;
5781 struct perf_event *event;
5783 mutex_lock(¤t->perf_event_mutex);
5784 list_for_each_entry(event, ¤t->perf_event_list, owner_entry) {
5785 ctx = perf_event_ctx_lock(event);
5786 perf_event_for_each_child(event, _perf_event_disable);
5787 perf_event_ctx_unlock(event, ctx);
5789 mutex_unlock(¤t->perf_event_mutex);
5794 static int perf_event_index(struct perf_event *event)
5796 if (event->hw.state & PERF_HES_STOPPED)
5799 if (event->state != PERF_EVENT_STATE_ACTIVE)
5802 return event->pmu->event_idx(event);
5805 static void calc_timer_values(struct perf_event *event,
5812 *now = perf_clock();
5813 ctx_time = event->shadow_ctx_time + *now;
5814 __perf_update_times(event, ctx_time, enabled, running);
5817 static void perf_event_init_userpage(struct perf_event *event)
5819 struct perf_event_mmap_page *userpg;
5820 struct perf_buffer *rb;
5823 rb = rcu_dereference(event->rb);
5827 userpg = rb->user_page;
5829 /* Allow new userspace to detect that bit 0 is deprecated */
5830 userpg->cap_bit0_is_deprecated = 1;
5831 userpg->size = offsetof(struct perf_event_mmap_page, __reserved);
5832 userpg->data_offset = PAGE_SIZE;
5833 userpg->data_size = perf_data_size(rb);
5839 void __weak arch_perf_update_userpage(
5840 struct perf_event *event, struct perf_event_mmap_page *userpg, u64 now)
5845 * Callers need to ensure there can be no nesting of this function, otherwise
5846 * the seqlock logic goes bad. We can not serialize this because the arch
5847 * code calls this from NMI context.
5849 void perf_event_update_userpage(struct perf_event *event)
5851 struct perf_event_mmap_page *userpg;
5852 struct perf_buffer *rb;
5853 u64 enabled, running, now;
5856 rb = rcu_dereference(event->rb);
5861 * compute total_time_enabled, total_time_running
5862 * based on snapshot values taken when the event
5863 * was last scheduled in.
5865 * we cannot simply called update_context_time()
5866 * because of locking issue as we can be called in
5869 calc_timer_values(event, &now, &enabled, &running);
5871 userpg = rb->user_page;
5873 * Disable preemption to guarantee consistent time stamps are stored to
5879 userpg->index = perf_event_index(event);
5880 userpg->offset = perf_event_count(event);
5882 userpg->offset -= local64_read(&event->hw.prev_count);
5884 userpg->time_enabled = enabled +
5885 atomic64_read(&event->child_total_time_enabled);
5887 userpg->time_running = running +
5888 atomic64_read(&event->child_total_time_running);
5890 arch_perf_update_userpage(event, userpg, now);
5898 EXPORT_SYMBOL_GPL(perf_event_update_userpage);
5900 static vm_fault_t perf_mmap_fault(struct vm_fault *vmf)
5902 struct perf_event *event = vmf->vma->vm_file->private_data;
5903 struct perf_buffer *rb;
5904 vm_fault_t ret = VM_FAULT_SIGBUS;
5906 if (vmf->flags & FAULT_FLAG_MKWRITE) {
5907 if (vmf->pgoff == 0)
5913 rb = rcu_dereference(event->rb);
5917 if (vmf->pgoff && (vmf->flags & FAULT_FLAG_WRITE))
5920 vmf->page = perf_mmap_to_page(rb, vmf->pgoff);
5924 get_page(vmf->page);
5925 vmf->page->mapping = vmf->vma->vm_file->f_mapping;
5926 vmf->page->index = vmf->pgoff;
5935 static void ring_buffer_attach(struct perf_event *event,
5936 struct perf_buffer *rb)
5938 struct perf_buffer *old_rb = NULL;
5939 unsigned long flags;
5943 * Should be impossible, we set this when removing
5944 * event->rb_entry and wait/clear when adding event->rb_entry.
5946 WARN_ON_ONCE(event->rcu_pending);
5949 spin_lock_irqsave(&old_rb->event_lock, flags);
5950 list_del_rcu(&event->rb_entry);
5951 spin_unlock_irqrestore(&old_rb->event_lock, flags);
5953 event->rcu_batches = get_state_synchronize_rcu();
5954 event->rcu_pending = 1;
5958 if (event->rcu_pending) {
5959 cond_synchronize_rcu(event->rcu_batches);
5960 event->rcu_pending = 0;
5963 spin_lock_irqsave(&rb->event_lock, flags);
5964 list_add_rcu(&event->rb_entry, &rb->event_list);
5965 spin_unlock_irqrestore(&rb->event_lock, flags);
5969 * Avoid racing with perf_mmap_close(AUX): stop the event
5970 * before swizzling the event::rb pointer; if it's getting
5971 * unmapped, its aux_mmap_count will be 0 and it won't
5972 * restart. See the comment in __perf_pmu_output_stop().
5974 * Data will inevitably be lost when set_output is done in
5975 * mid-air, but then again, whoever does it like this is
5976 * not in for the data anyway.
5979 perf_event_stop(event, 0);
5981 rcu_assign_pointer(event->rb, rb);
5984 ring_buffer_put(old_rb);
5986 * Since we detached before setting the new rb, so that we
5987 * could attach the new rb, we could have missed a wakeup.
5990 wake_up_all(&event->waitq);
5994 static void ring_buffer_wakeup(struct perf_event *event)
5996 struct perf_buffer *rb;
5999 rb = rcu_dereference(event->rb);
6001 list_for_each_entry_rcu(event, &rb->event_list, rb_entry)
6002 wake_up_all(&event->waitq);
6007 struct perf_buffer *ring_buffer_get(struct perf_event *event)
6009 struct perf_buffer *rb;
6012 rb = rcu_dereference(event->rb);
6014 if (!refcount_inc_not_zero(&rb->refcount))
6022 void ring_buffer_put(struct perf_buffer *rb)
6024 if (!refcount_dec_and_test(&rb->refcount))
6027 WARN_ON_ONCE(!list_empty(&rb->event_list));
6029 call_rcu(&rb->rcu_head, rb_free_rcu);
6032 static void perf_mmap_open(struct vm_area_struct *vma)
6034 struct perf_event *event = vma->vm_file->private_data;
6036 atomic_inc(&event->mmap_count);
6037 atomic_inc(&event->rb->mmap_count);
6040 atomic_inc(&event->rb->aux_mmap_count);
6042 if (event->pmu->event_mapped)
6043 event->pmu->event_mapped(event, vma->vm_mm);
6046 static void perf_pmu_output_stop(struct perf_event *event);
6049 * A buffer can be mmap()ed multiple times; either directly through the same
6050 * event, or through other events by use of perf_event_set_output().
6052 * In order to undo the VM accounting done by perf_mmap() we need to destroy
6053 * the buffer here, where we still have a VM context. This means we need
6054 * to detach all events redirecting to us.
6056 static void perf_mmap_close(struct vm_area_struct *vma)
6058 struct perf_event *event = vma->vm_file->private_data;
6059 struct perf_buffer *rb = ring_buffer_get(event);
6060 struct user_struct *mmap_user = rb->mmap_user;
6061 int mmap_locked = rb->mmap_locked;
6062 unsigned long size = perf_data_size(rb);
6063 bool detach_rest = false;
6065 if (event->pmu->event_unmapped)
6066 event->pmu->event_unmapped(event, vma->vm_mm);
6069 * rb->aux_mmap_count will always drop before rb->mmap_count and
6070 * event->mmap_count, so it is ok to use event->mmap_mutex to
6071 * serialize with perf_mmap here.
6073 if (rb_has_aux(rb) && vma->vm_pgoff == rb->aux_pgoff &&
6074 atomic_dec_and_mutex_lock(&rb->aux_mmap_count, &event->mmap_mutex)) {
6076 * Stop all AUX events that are writing to this buffer,
6077 * so that we can free its AUX pages and corresponding PMU
6078 * data. Note that after rb::aux_mmap_count dropped to zero,
6079 * they won't start any more (see perf_aux_output_begin()).
6081 perf_pmu_output_stop(event);
6083 /* now it's safe to free the pages */
6084 atomic_long_sub(rb->aux_nr_pages - rb->aux_mmap_locked, &mmap_user->locked_vm);
6085 atomic64_sub(rb->aux_mmap_locked, &vma->vm_mm->pinned_vm);
6087 /* this has to be the last one */
6089 WARN_ON_ONCE(refcount_read(&rb->aux_refcount));
6091 mutex_unlock(&event->mmap_mutex);
6094 if (atomic_dec_and_test(&rb->mmap_count))
6097 if (!atomic_dec_and_mutex_lock(&event->mmap_count, &event->mmap_mutex))
6100 ring_buffer_attach(event, NULL);
6101 mutex_unlock(&event->mmap_mutex);
6103 /* If there's still other mmap()s of this buffer, we're done. */
6108 * No other mmap()s, detach from all other events that might redirect
6109 * into the now unreachable buffer. Somewhat complicated by the
6110 * fact that rb::event_lock otherwise nests inside mmap_mutex.
6114 list_for_each_entry_rcu(event, &rb->event_list, rb_entry) {
6115 if (!atomic_long_inc_not_zero(&event->refcount)) {
6117 * This event is en-route to free_event() which will
6118 * detach it and remove it from the list.
6124 mutex_lock(&event->mmap_mutex);
6126 * Check we didn't race with perf_event_set_output() which can
6127 * swizzle the rb from under us while we were waiting to
6128 * acquire mmap_mutex.
6130 * If we find a different rb; ignore this event, a next
6131 * iteration will no longer find it on the list. We have to
6132 * still restart the iteration to make sure we're not now
6133 * iterating the wrong list.
6135 if (event->rb == rb)
6136 ring_buffer_attach(event, NULL);
6138 mutex_unlock(&event->mmap_mutex);
6142 * Restart the iteration; either we're on the wrong list or
6143 * destroyed its integrity by doing a deletion.
6150 * It could be there's still a few 0-ref events on the list; they'll
6151 * get cleaned up by free_event() -- they'll also still have their
6152 * ref on the rb and will free it whenever they are done with it.
6154 * Aside from that, this buffer is 'fully' detached and unmapped,
6155 * undo the VM accounting.
6158 atomic_long_sub((size >> PAGE_SHIFT) + 1 - mmap_locked,
6159 &mmap_user->locked_vm);
6160 atomic64_sub(mmap_locked, &vma->vm_mm->pinned_vm);
6161 free_uid(mmap_user);
6164 ring_buffer_put(rb); /* could be last */
6167 static const struct vm_operations_struct perf_mmap_vmops = {
6168 .open = perf_mmap_open,
6169 .close = perf_mmap_close, /* non mergeable */
6170 .fault = perf_mmap_fault,
6171 .page_mkwrite = perf_mmap_fault,
6174 static int perf_mmap(struct file *file, struct vm_area_struct *vma)
6176 struct perf_event *event = file->private_data;
6177 unsigned long user_locked, user_lock_limit;
6178 struct user_struct *user = current_user();
6179 struct perf_buffer *rb = NULL;
6180 unsigned long locked, lock_limit;
6181 unsigned long vma_size;
6182 unsigned long nr_pages;
6183 long user_extra = 0, extra = 0;
6184 int ret = 0, flags = 0;
6187 * Don't allow mmap() of inherited per-task counters. This would
6188 * create a performance issue due to all children writing to the
6191 if (event->cpu == -1 && event->attr.inherit)
6194 if (!(vma->vm_flags & VM_SHARED))
6197 ret = security_perf_event_read(event);
6201 vma_size = vma->vm_end - vma->vm_start;
6203 if (vma->vm_pgoff == 0) {
6204 nr_pages = (vma_size / PAGE_SIZE) - 1;
6207 * AUX area mapping: if rb->aux_nr_pages != 0, it's already
6208 * mapped, all subsequent mappings should have the same size
6209 * and offset. Must be above the normal perf buffer.
6211 u64 aux_offset, aux_size;
6216 nr_pages = vma_size / PAGE_SIZE;
6218 mutex_lock(&event->mmap_mutex);
6225 aux_offset = READ_ONCE(rb->user_page->aux_offset);
6226 aux_size = READ_ONCE(rb->user_page->aux_size);
6228 if (aux_offset < perf_data_size(rb) + PAGE_SIZE)
6231 if (aux_offset != vma->vm_pgoff << PAGE_SHIFT)
6234 /* already mapped with a different offset */
6235 if (rb_has_aux(rb) && rb->aux_pgoff != vma->vm_pgoff)
6238 if (aux_size != vma_size || aux_size != nr_pages * PAGE_SIZE)
6241 /* already mapped with a different size */
6242 if (rb_has_aux(rb) && rb->aux_nr_pages != nr_pages)
6245 if (!is_power_of_2(nr_pages))
6248 if (!atomic_inc_not_zero(&rb->mmap_count))
6251 if (rb_has_aux(rb)) {
6252 atomic_inc(&rb->aux_mmap_count);
6257 atomic_set(&rb->aux_mmap_count, 1);
6258 user_extra = nr_pages;
6264 * If we have rb pages ensure they're a power-of-two number, so we
6265 * can do bitmasks instead of modulo.
6267 if (nr_pages != 0 && !is_power_of_2(nr_pages))
6270 if (vma_size != PAGE_SIZE * (1 + nr_pages))
6273 WARN_ON_ONCE(event->ctx->parent_ctx);
6275 mutex_lock(&event->mmap_mutex);
6277 if (event->rb->nr_pages != nr_pages) {
6282 if (!atomic_inc_not_zero(&event->rb->mmap_count)) {
6284 * Raced against perf_mmap_close() through
6285 * perf_event_set_output(). Try again, hope for better
6288 mutex_unlock(&event->mmap_mutex);
6295 user_extra = nr_pages + 1;
6298 user_lock_limit = sysctl_perf_event_mlock >> (PAGE_SHIFT - 10);
6301 * Increase the limit linearly with more CPUs:
6303 user_lock_limit *= num_online_cpus();
6305 user_locked = atomic_long_read(&user->locked_vm);
6308 * sysctl_perf_event_mlock may have changed, so that
6309 * user->locked_vm > user_lock_limit
6311 if (user_locked > user_lock_limit)
6312 user_locked = user_lock_limit;
6313 user_locked += user_extra;
6315 if (user_locked > user_lock_limit) {
6317 * charge locked_vm until it hits user_lock_limit;
6318 * charge the rest from pinned_vm
6320 extra = user_locked - user_lock_limit;
6321 user_extra -= extra;
6324 lock_limit = rlimit(RLIMIT_MEMLOCK);
6325 lock_limit >>= PAGE_SHIFT;
6326 locked = atomic64_read(&vma->vm_mm->pinned_vm) + extra;
6328 if ((locked > lock_limit) && perf_is_paranoid() &&
6329 !capable(CAP_IPC_LOCK)) {
6334 WARN_ON(!rb && event->rb);
6336 if (vma->vm_flags & VM_WRITE)
6337 flags |= RING_BUFFER_WRITABLE;
6340 rb = rb_alloc(nr_pages,
6341 event->attr.watermark ? event->attr.wakeup_watermark : 0,
6349 atomic_set(&rb->mmap_count, 1);
6350 rb->mmap_user = get_current_user();
6351 rb->mmap_locked = extra;
6353 ring_buffer_attach(event, rb);
6355 perf_event_update_time(event);
6356 perf_set_shadow_time(event, event->ctx);
6357 perf_event_init_userpage(event);
6358 perf_event_update_userpage(event);
6360 ret = rb_alloc_aux(rb, event, vma->vm_pgoff, nr_pages,
6361 event->attr.aux_watermark, flags);
6363 rb->aux_mmap_locked = extra;
6368 atomic_long_add(user_extra, &user->locked_vm);
6369 atomic64_add(extra, &vma->vm_mm->pinned_vm);
6371 atomic_inc(&event->mmap_count);
6373 atomic_dec(&rb->mmap_count);
6376 mutex_unlock(&event->mmap_mutex);
6379 * Since pinned accounting is per vm we cannot allow fork() to copy our
6382 vma->vm_flags |= VM_DONTCOPY | VM_DONTEXPAND | VM_DONTDUMP;
6383 vma->vm_ops = &perf_mmap_vmops;
6385 if (event->pmu->event_mapped)
6386 event->pmu->event_mapped(event, vma->vm_mm);
6391 static int perf_fasync(int fd, struct file *filp, int on)
6393 struct inode *inode = file_inode(filp);
6394 struct perf_event *event = filp->private_data;
6398 retval = fasync_helper(fd, filp, on, &event->fasync);
6399 inode_unlock(inode);
6407 static const struct file_operations perf_fops = {
6408 .llseek = no_llseek,
6409 .release = perf_release,
6412 .unlocked_ioctl = perf_ioctl,
6413 .compat_ioctl = perf_compat_ioctl,
6415 .fasync = perf_fasync,
6421 * If there's data, ensure we set the poll() state and publish everything
6422 * to user-space before waking everybody up.
6425 static inline struct fasync_struct **perf_event_fasync(struct perf_event *event)
6427 /* only the parent has fasync state */
6429 event = event->parent;
6430 return &event->fasync;
6433 void perf_event_wakeup(struct perf_event *event)
6435 ring_buffer_wakeup(event);
6437 if (event->pending_kill) {
6438 kill_fasync(perf_event_fasync(event), SIGIO, event->pending_kill);
6439 event->pending_kill = 0;
6443 static void perf_sigtrap(struct perf_event *event)
6446 * We'd expect this to only occur if the irq_work is delayed and either
6447 * ctx->task or current has changed in the meantime. This can be the
6448 * case on architectures that do not implement arch_irq_work_raise().
6450 if (WARN_ON_ONCE(event->ctx->task != current))
6454 * perf_pending_event() can race with the task exiting.
6456 if (current->flags & PF_EXITING)
6459 force_sig_perf((void __user *)event->pending_addr,
6460 event->attr.type, event->attr.sig_data);
6463 static void perf_pending_event_disable(struct perf_event *event)
6465 int cpu = READ_ONCE(event->pending_disable);
6470 if (cpu == smp_processor_id()) {
6471 WRITE_ONCE(event->pending_disable, -1);
6473 if (event->attr.sigtrap) {
6474 perf_sigtrap(event);
6475 atomic_set_release(&event->event_limit, 1); /* rearm event */
6479 perf_event_disable_local(event);
6486 * perf_event_disable_inatomic()
6487 * @pending_disable = CPU-A;
6491 * @pending_disable = -1;
6494 * perf_event_disable_inatomic()
6495 * @pending_disable = CPU-B;
6496 * irq_work_queue(); // FAILS
6499 * perf_pending_event()
6501 * But the event runs on CPU-B and wants disabling there.
6503 irq_work_queue_on(&event->pending, cpu);
6506 static void perf_pending_event(struct irq_work *entry)
6508 struct perf_event *event = container_of(entry, struct perf_event, pending);
6511 rctx = perf_swevent_get_recursion_context();
6513 * If we 'fail' here, that's OK, it means recursion is already disabled
6514 * and we won't recurse 'further'.
6517 perf_pending_event_disable(event);
6519 if (event->pending_wakeup) {
6520 event->pending_wakeup = 0;
6521 perf_event_wakeup(event);
6525 perf_swevent_put_recursion_context(rctx);
6528 #ifdef CONFIG_GUEST_PERF_EVENTS
6529 struct perf_guest_info_callbacks __rcu *perf_guest_cbs;
6531 DEFINE_STATIC_CALL_RET0(__perf_guest_state, *perf_guest_cbs->state);
6532 DEFINE_STATIC_CALL_RET0(__perf_guest_get_ip, *perf_guest_cbs->get_ip);
6533 DEFINE_STATIC_CALL_RET0(__perf_guest_handle_intel_pt_intr, *perf_guest_cbs->handle_intel_pt_intr);
6535 void perf_register_guest_info_callbacks(struct perf_guest_info_callbacks *cbs)
6537 if (WARN_ON_ONCE(rcu_access_pointer(perf_guest_cbs)))
6540 rcu_assign_pointer(perf_guest_cbs, cbs);
6541 static_call_update(__perf_guest_state, cbs->state);
6542 static_call_update(__perf_guest_get_ip, cbs->get_ip);
6544 /* Implementing ->handle_intel_pt_intr is optional. */
6545 if (cbs->handle_intel_pt_intr)
6546 static_call_update(__perf_guest_handle_intel_pt_intr,
6547 cbs->handle_intel_pt_intr);
6549 EXPORT_SYMBOL_GPL(perf_register_guest_info_callbacks);
6551 void perf_unregister_guest_info_callbacks(struct perf_guest_info_callbacks *cbs)
6553 if (WARN_ON_ONCE(rcu_access_pointer(perf_guest_cbs) != cbs))
6556 rcu_assign_pointer(perf_guest_cbs, NULL);
6557 static_call_update(__perf_guest_state, (void *)&__static_call_return0);
6558 static_call_update(__perf_guest_get_ip, (void *)&__static_call_return0);
6559 static_call_update(__perf_guest_handle_intel_pt_intr,
6560 (void *)&__static_call_return0);
6563 EXPORT_SYMBOL_GPL(perf_unregister_guest_info_callbacks);
6567 perf_output_sample_regs(struct perf_output_handle *handle,
6568 struct pt_regs *regs, u64 mask)
6571 DECLARE_BITMAP(_mask, 64);
6573 bitmap_from_u64(_mask, mask);
6574 for_each_set_bit(bit, _mask, sizeof(mask) * BITS_PER_BYTE) {
6577 val = perf_reg_value(regs, bit);
6578 perf_output_put(handle, val);
6582 static void perf_sample_regs_user(struct perf_regs *regs_user,
6583 struct pt_regs *regs)
6585 if (user_mode(regs)) {
6586 regs_user->abi = perf_reg_abi(current);
6587 regs_user->regs = regs;
6588 } else if (!(current->flags & PF_KTHREAD)) {
6589 perf_get_regs_user(regs_user, regs);
6591 regs_user->abi = PERF_SAMPLE_REGS_ABI_NONE;
6592 regs_user->regs = NULL;
6596 static void perf_sample_regs_intr(struct perf_regs *regs_intr,
6597 struct pt_regs *regs)
6599 regs_intr->regs = regs;
6600 regs_intr->abi = perf_reg_abi(current);
6605 * Get remaining task size from user stack pointer.
6607 * It'd be better to take stack vma map and limit this more
6608 * precisely, but there's no way to get it safely under interrupt,
6609 * so using TASK_SIZE as limit.
6611 static u64 perf_ustack_task_size(struct pt_regs *regs)
6613 unsigned long addr = perf_user_stack_pointer(regs);
6615 if (!addr || addr >= TASK_SIZE)
6618 return TASK_SIZE - addr;
6622 perf_sample_ustack_size(u16 stack_size, u16 header_size,
6623 struct pt_regs *regs)
6627 /* No regs, no stack pointer, no dump. */
6632 * Check if we fit in with the requested stack size into the:
6634 * If we don't, we limit the size to the TASK_SIZE.
6636 * - remaining sample size
6637 * If we don't, we customize the stack size to
6638 * fit in to the remaining sample size.
6641 task_size = min((u64) USHRT_MAX, perf_ustack_task_size(regs));
6642 stack_size = min(stack_size, (u16) task_size);
6644 /* Current header size plus static size and dynamic size. */
6645 header_size += 2 * sizeof(u64);
6647 /* Do we fit in with the current stack dump size? */
6648 if ((u16) (header_size + stack_size) < header_size) {
6650 * If we overflow the maximum size for the sample,
6651 * we customize the stack dump size to fit in.
6653 stack_size = USHRT_MAX - header_size - sizeof(u64);
6654 stack_size = round_up(stack_size, sizeof(u64));
6661 perf_output_sample_ustack(struct perf_output_handle *handle, u64 dump_size,
6662 struct pt_regs *regs)
6664 /* Case of a kernel thread, nothing to dump */
6667 perf_output_put(handle, size);
6677 * - the size requested by user or the best one we can fit
6678 * in to the sample max size
6680 * - user stack dump data
6682 * - the actual dumped size
6686 perf_output_put(handle, dump_size);
6689 sp = perf_user_stack_pointer(regs);
6690 fs = force_uaccess_begin();
6691 rem = __output_copy_user(handle, (void *) sp, dump_size);
6692 force_uaccess_end(fs);
6693 dyn_size = dump_size - rem;
6695 perf_output_skip(handle, rem);
6698 perf_output_put(handle, dyn_size);
6702 static unsigned long perf_prepare_sample_aux(struct perf_event *event,
6703 struct perf_sample_data *data,
6706 struct perf_event *sampler = event->aux_event;
6707 struct perf_buffer *rb;
6714 if (WARN_ON_ONCE(READ_ONCE(sampler->state) != PERF_EVENT_STATE_ACTIVE))
6717 if (WARN_ON_ONCE(READ_ONCE(sampler->oncpu) != smp_processor_id()))
6720 rb = ring_buffer_get(sampler->parent ? sampler->parent : sampler);
6725 * If this is an NMI hit inside sampling code, don't take
6726 * the sample. See also perf_aux_sample_output().
6728 if (READ_ONCE(rb->aux_in_sampling)) {
6731 size = min_t(size_t, size, perf_aux_size(rb));
6732 data->aux_size = ALIGN(size, sizeof(u64));
6734 ring_buffer_put(rb);
6737 return data->aux_size;
6740 static long perf_pmu_snapshot_aux(struct perf_buffer *rb,
6741 struct perf_event *event,
6742 struct perf_output_handle *handle,
6745 unsigned long flags;
6749 * Normal ->start()/->stop() callbacks run in IRQ mode in scheduler
6750 * paths. If we start calling them in NMI context, they may race with
6751 * the IRQ ones, that is, for example, re-starting an event that's just
6752 * been stopped, which is why we're using a separate callback that
6753 * doesn't change the event state.
6755 * IRQs need to be disabled to prevent IPIs from racing with us.
6757 local_irq_save(flags);
6759 * Guard against NMI hits inside the critical section;
6760 * see also perf_prepare_sample_aux().
6762 WRITE_ONCE(rb->aux_in_sampling, 1);
6765 ret = event->pmu->snapshot_aux(event, handle, size);
6768 WRITE_ONCE(rb->aux_in_sampling, 0);
6769 local_irq_restore(flags);
6774 static void perf_aux_sample_output(struct perf_event *event,
6775 struct perf_output_handle *handle,
6776 struct perf_sample_data *data)
6778 struct perf_event *sampler = event->aux_event;
6779 struct perf_buffer *rb;
6783 if (WARN_ON_ONCE(!sampler || !data->aux_size))
6786 rb = ring_buffer_get(sampler->parent ? sampler->parent : sampler);
6790 size = perf_pmu_snapshot_aux(rb, sampler, handle, data->aux_size);
6793 * An error here means that perf_output_copy() failed (returned a
6794 * non-zero surplus that it didn't copy), which in its current
6795 * enlightened implementation is not possible. If that changes, we'd
6798 if (WARN_ON_ONCE(size < 0))
6802 * The pad comes from ALIGN()ing data->aux_size up to u64 in
6803 * perf_prepare_sample_aux(), so should not be more than that.
6805 pad = data->aux_size - size;
6806 if (WARN_ON_ONCE(pad >= sizeof(u64)))
6811 perf_output_copy(handle, &zero, pad);
6815 ring_buffer_put(rb);
6818 static void __perf_event_header__init_id(struct perf_event_header *header,
6819 struct perf_sample_data *data,
6820 struct perf_event *event)
6822 u64 sample_type = event->attr.sample_type;
6824 data->type = sample_type;
6825 header->size += event->id_header_size;
6827 if (sample_type & PERF_SAMPLE_TID) {
6828 /* namespace issues */
6829 data->tid_entry.pid = perf_event_pid(event, current);
6830 data->tid_entry.tid = perf_event_tid(event, current);
6833 if (sample_type & PERF_SAMPLE_TIME)
6834 data->time = perf_event_clock(event);
6836 if (sample_type & (PERF_SAMPLE_ID | PERF_SAMPLE_IDENTIFIER))
6837 data->id = primary_event_id(event);
6839 if (sample_type & PERF_SAMPLE_STREAM_ID)
6840 data->stream_id = event->id;
6842 if (sample_type & PERF_SAMPLE_CPU) {
6843 data->cpu_entry.cpu = raw_smp_processor_id();
6844 data->cpu_entry.reserved = 0;
6848 void perf_event_header__init_id(struct perf_event_header *header,
6849 struct perf_sample_data *data,
6850 struct perf_event *event)
6852 if (event->attr.sample_id_all)
6853 __perf_event_header__init_id(header, data, event);
6856 static void __perf_event__output_id_sample(struct perf_output_handle *handle,
6857 struct perf_sample_data *data)
6859 u64 sample_type = data->type;
6861 if (sample_type & PERF_SAMPLE_TID)
6862 perf_output_put(handle, data->tid_entry);
6864 if (sample_type & PERF_SAMPLE_TIME)
6865 perf_output_put(handle, data->time);
6867 if (sample_type & PERF_SAMPLE_ID)
6868 perf_output_put(handle, data->id);
6870 if (sample_type & PERF_SAMPLE_STREAM_ID)
6871 perf_output_put(handle, data->stream_id);
6873 if (sample_type & PERF_SAMPLE_CPU)
6874 perf_output_put(handle, data->cpu_entry);
6876 if (sample_type & PERF_SAMPLE_IDENTIFIER)
6877 perf_output_put(handle, data->id);
6880 void perf_event__output_id_sample(struct perf_event *event,
6881 struct perf_output_handle *handle,
6882 struct perf_sample_data *sample)
6884 if (event->attr.sample_id_all)
6885 __perf_event__output_id_sample(handle, sample);
6888 static void perf_output_read_one(struct perf_output_handle *handle,
6889 struct perf_event *event,
6890 u64 enabled, u64 running)
6892 u64 read_format = event->attr.read_format;
6896 values[n++] = perf_event_count(event);
6897 if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED) {
6898 values[n++] = enabled +
6899 atomic64_read(&event->child_total_time_enabled);
6901 if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING) {
6902 values[n++] = running +
6903 atomic64_read(&event->child_total_time_running);
6905 if (read_format & PERF_FORMAT_ID)
6906 values[n++] = primary_event_id(event);
6908 __output_copy(handle, values, n * sizeof(u64));
6911 static void perf_output_read_group(struct perf_output_handle *handle,
6912 struct perf_event *event,
6913 u64 enabled, u64 running)
6915 struct perf_event *leader = event->group_leader, *sub;
6916 u64 read_format = event->attr.read_format;
6920 values[n++] = 1 + leader->nr_siblings;
6922 if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED)
6923 values[n++] = enabled;
6925 if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING)
6926 values[n++] = running;
6928 if ((leader != event) &&
6929 (leader->state == PERF_EVENT_STATE_ACTIVE))
6930 leader->pmu->read(leader);
6932 values[n++] = perf_event_count(leader);
6933 if (read_format & PERF_FORMAT_ID)
6934 values[n++] = primary_event_id(leader);
6936 __output_copy(handle, values, n * sizeof(u64));
6938 for_each_sibling_event(sub, leader) {
6941 if ((sub != event) &&
6942 (sub->state == PERF_EVENT_STATE_ACTIVE))
6943 sub->pmu->read(sub);
6945 values[n++] = perf_event_count(sub);
6946 if (read_format & PERF_FORMAT_ID)
6947 values[n++] = primary_event_id(sub);
6949 __output_copy(handle, values, n * sizeof(u64));
6953 #define PERF_FORMAT_TOTAL_TIMES (PERF_FORMAT_TOTAL_TIME_ENABLED|\
6954 PERF_FORMAT_TOTAL_TIME_RUNNING)
6957 * XXX PERF_SAMPLE_READ vs inherited events seems difficult.
6959 * The problem is that its both hard and excessively expensive to iterate the
6960 * child list, not to mention that its impossible to IPI the children running
6961 * on another CPU, from interrupt/NMI context.
6963 static void perf_output_read(struct perf_output_handle *handle,
6964 struct perf_event *event)
6966 u64 enabled = 0, running = 0, now;
6967 u64 read_format = event->attr.read_format;
6970 * compute total_time_enabled, total_time_running
6971 * based on snapshot values taken when the event
6972 * was last scheduled in.
6974 * we cannot simply called update_context_time()
6975 * because of locking issue as we are called in
6978 if (read_format & PERF_FORMAT_TOTAL_TIMES)
6979 calc_timer_values(event, &now, &enabled, &running);
6981 if (event->attr.read_format & PERF_FORMAT_GROUP)
6982 perf_output_read_group(handle, event, enabled, running);
6984 perf_output_read_one(handle, event, enabled, running);
6987 static inline bool perf_sample_save_hw_index(struct perf_event *event)
6989 return event->attr.branch_sample_type & PERF_SAMPLE_BRANCH_HW_INDEX;
6992 void perf_output_sample(struct perf_output_handle *handle,
6993 struct perf_event_header *header,
6994 struct perf_sample_data *data,
6995 struct perf_event *event)
6997 u64 sample_type = data->type;
6999 perf_output_put(handle, *header);
7001 if (sample_type & PERF_SAMPLE_IDENTIFIER)
7002 perf_output_put(handle, data->id);
7004 if (sample_type & PERF_SAMPLE_IP)
7005 perf_output_put(handle, data->ip);
7007 if (sample_type & PERF_SAMPLE_TID)
7008 perf_output_put(handle, data->tid_entry);
7010 if (sample_type & PERF_SAMPLE_TIME)
7011 perf_output_put(handle, data->time);
7013 if (sample_type & PERF_SAMPLE_ADDR)
7014 perf_output_put(handle, data->addr);
7016 if (sample_type & PERF_SAMPLE_ID)
7017 perf_output_put(handle, data->id);
7019 if (sample_type & PERF_SAMPLE_STREAM_ID)
7020 perf_output_put(handle, data->stream_id);
7022 if (sample_type & PERF_SAMPLE_CPU)
7023 perf_output_put(handle, data->cpu_entry);
7025 if (sample_type & PERF_SAMPLE_PERIOD)
7026 perf_output_put(handle, data->period);
7028 if (sample_type & PERF_SAMPLE_READ)
7029 perf_output_read(handle, event);
7031 if (sample_type & PERF_SAMPLE_CALLCHAIN) {
7034 size += data->callchain->nr;
7035 size *= sizeof(u64);
7036 __output_copy(handle, data->callchain, size);
7039 if (sample_type & PERF_SAMPLE_RAW) {
7040 struct perf_raw_record *raw = data->raw;
7043 struct perf_raw_frag *frag = &raw->frag;
7045 perf_output_put(handle, raw->size);
7048 __output_custom(handle, frag->copy,
7049 frag->data, frag->size);
7051 __output_copy(handle, frag->data,
7054 if (perf_raw_frag_last(frag))
7059 __output_skip(handle, NULL, frag->pad);
7065 .size = sizeof(u32),
7068 perf_output_put(handle, raw);
7072 if (sample_type & PERF_SAMPLE_BRANCH_STACK) {
7073 if (data->br_stack) {
7076 size = data->br_stack->nr
7077 * sizeof(struct perf_branch_entry);
7079 perf_output_put(handle, data->br_stack->nr);
7080 if (perf_sample_save_hw_index(event))
7081 perf_output_put(handle, data->br_stack->hw_idx);
7082 perf_output_copy(handle, data->br_stack->entries, size);
7085 * we always store at least the value of nr
7088 perf_output_put(handle, nr);
7092 if (sample_type & PERF_SAMPLE_REGS_USER) {
7093 u64 abi = data->regs_user.abi;
7096 * If there are no regs to dump, notice it through
7097 * first u64 being zero (PERF_SAMPLE_REGS_ABI_NONE).
7099 perf_output_put(handle, abi);
7102 u64 mask = event->attr.sample_regs_user;
7103 perf_output_sample_regs(handle,
7104 data->regs_user.regs,
7109 if (sample_type & PERF_SAMPLE_STACK_USER) {
7110 perf_output_sample_ustack(handle,
7111 data->stack_user_size,
7112 data->regs_user.regs);
7115 if (sample_type & PERF_SAMPLE_WEIGHT_TYPE)
7116 perf_output_put(handle, data->weight.full);
7118 if (sample_type & PERF_SAMPLE_DATA_SRC)
7119 perf_output_put(handle, data->data_src.val);
7121 if (sample_type & PERF_SAMPLE_TRANSACTION)
7122 perf_output_put(handle, data->txn);
7124 if (sample_type & PERF_SAMPLE_REGS_INTR) {
7125 u64 abi = data->regs_intr.abi;
7127 * If there are no regs to dump, notice it through
7128 * first u64 being zero (PERF_SAMPLE_REGS_ABI_NONE).
7130 perf_output_put(handle, abi);
7133 u64 mask = event->attr.sample_regs_intr;
7135 perf_output_sample_regs(handle,
7136 data->regs_intr.regs,
7141 if (sample_type & PERF_SAMPLE_PHYS_ADDR)
7142 perf_output_put(handle, data->phys_addr);
7144 if (sample_type & PERF_SAMPLE_CGROUP)
7145 perf_output_put(handle, data->cgroup);
7147 if (sample_type & PERF_SAMPLE_DATA_PAGE_SIZE)
7148 perf_output_put(handle, data->data_page_size);
7150 if (sample_type & PERF_SAMPLE_CODE_PAGE_SIZE)
7151 perf_output_put(handle, data->code_page_size);
7153 if (sample_type & PERF_SAMPLE_AUX) {
7154 perf_output_put(handle, data->aux_size);
7157 perf_aux_sample_output(event, handle, data);
7160 if (!event->attr.watermark) {
7161 int wakeup_events = event->attr.wakeup_events;
7163 if (wakeup_events) {
7164 struct perf_buffer *rb = handle->rb;
7165 int events = local_inc_return(&rb->events);
7167 if (events >= wakeup_events) {
7168 local_sub(wakeup_events, &rb->events);
7169 local_inc(&rb->wakeup);
7175 static u64 perf_virt_to_phys(u64 virt)
7182 if (virt >= TASK_SIZE) {
7183 /* If it's vmalloc()d memory, leave phys_addr as 0 */
7184 if (virt_addr_valid((void *)(uintptr_t)virt) &&
7185 !(virt >= VMALLOC_START && virt < VMALLOC_END))
7186 phys_addr = (u64)virt_to_phys((void *)(uintptr_t)virt);
7189 * Walking the pages tables for user address.
7190 * Interrupts are disabled, so it prevents any tear down
7191 * of the page tables.
7192 * Try IRQ-safe get_user_page_fast_only first.
7193 * If failed, leave phys_addr as 0.
7195 if (current->mm != NULL) {
7198 pagefault_disable();
7199 if (get_user_page_fast_only(virt, 0, &p)) {
7200 phys_addr = page_to_phys(p) + virt % PAGE_SIZE;
7211 * Return the pagetable size of a given virtual address.
7213 static u64 perf_get_pgtable_size(struct mm_struct *mm, unsigned long addr)
7217 #ifdef CONFIG_HAVE_FAST_GUP
7224 pgdp = pgd_offset(mm, addr);
7225 pgd = READ_ONCE(*pgdp);
7230 return pgd_leaf_size(pgd);
7232 p4dp = p4d_offset_lockless(pgdp, pgd, addr);
7233 p4d = READ_ONCE(*p4dp);
7234 if (!p4d_present(p4d))
7238 return p4d_leaf_size(p4d);
7240 pudp = pud_offset_lockless(p4dp, p4d, addr);
7241 pud = READ_ONCE(*pudp);
7242 if (!pud_present(pud))
7246 return pud_leaf_size(pud);
7248 pmdp = pmd_offset_lockless(pudp, pud, addr);
7249 pmd = READ_ONCE(*pmdp);
7250 if (!pmd_present(pmd))
7254 return pmd_leaf_size(pmd);
7256 ptep = pte_offset_map(&pmd, addr);
7257 pte = ptep_get_lockless(ptep);
7258 if (pte_present(pte))
7259 size = pte_leaf_size(pte);
7261 #endif /* CONFIG_HAVE_FAST_GUP */
7266 static u64 perf_get_page_size(unsigned long addr)
7268 struct mm_struct *mm;
7269 unsigned long flags;
7276 * Software page-table walkers must disable IRQs,
7277 * which prevents any tear down of the page tables.
7279 local_irq_save(flags);
7284 * For kernel threads and the like, use init_mm so that
7285 * we can find kernel memory.
7290 size = perf_get_pgtable_size(mm, addr);
7292 local_irq_restore(flags);
7297 static struct perf_callchain_entry __empty_callchain = { .nr = 0, };
7299 struct perf_callchain_entry *
7300 perf_callchain(struct perf_event *event, struct pt_regs *regs)
7302 bool kernel = !event->attr.exclude_callchain_kernel;
7303 bool user = !event->attr.exclude_callchain_user;
7304 /* Disallow cross-task user callchains. */
7305 bool crosstask = event->ctx->task && event->ctx->task != current;
7306 const u32 max_stack = event->attr.sample_max_stack;
7307 struct perf_callchain_entry *callchain;
7309 if (!kernel && !user)
7310 return &__empty_callchain;
7312 callchain = get_perf_callchain(regs, 0, kernel, user,
7313 max_stack, crosstask, true);
7314 return callchain ?: &__empty_callchain;
7317 void perf_prepare_sample(struct perf_event_header *header,
7318 struct perf_sample_data *data,
7319 struct perf_event *event,
7320 struct pt_regs *regs)
7322 u64 sample_type = event->attr.sample_type;
7324 header->type = PERF_RECORD_SAMPLE;
7325 header->size = sizeof(*header) + event->header_size;
7328 header->misc |= perf_misc_flags(regs);
7330 __perf_event_header__init_id(header, data, event);
7332 if (sample_type & (PERF_SAMPLE_IP | PERF_SAMPLE_CODE_PAGE_SIZE))
7333 data->ip = perf_instruction_pointer(regs);
7335 if (sample_type & PERF_SAMPLE_CALLCHAIN) {
7338 if (!(sample_type & __PERF_SAMPLE_CALLCHAIN_EARLY))
7339 data->callchain = perf_callchain(event, regs);
7341 size += data->callchain->nr;
7343 header->size += size * sizeof(u64);
7346 if (sample_type & PERF_SAMPLE_RAW) {
7347 struct perf_raw_record *raw = data->raw;
7351 struct perf_raw_frag *frag = &raw->frag;
7356 if (perf_raw_frag_last(frag))
7361 size = round_up(sum + sizeof(u32), sizeof(u64));
7362 raw->size = size - sizeof(u32);
7363 frag->pad = raw->size - sum;
7368 header->size += size;
7371 if (sample_type & PERF_SAMPLE_BRANCH_STACK) {
7372 int size = sizeof(u64); /* nr */
7373 if (data->br_stack) {
7374 if (perf_sample_save_hw_index(event))
7375 size += sizeof(u64);
7377 size += data->br_stack->nr
7378 * sizeof(struct perf_branch_entry);
7380 header->size += size;
7383 if (sample_type & (PERF_SAMPLE_REGS_USER | PERF_SAMPLE_STACK_USER))
7384 perf_sample_regs_user(&data->regs_user, regs);
7386 if (sample_type & PERF_SAMPLE_REGS_USER) {
7387 /* regs dump ABI info */
7388 int size = sizeof(u64);
7390 if (data->regs_user.regs) {
7391 u64 mask = event->attr.sample_regs_user;
7392 size += hweight64(mask) * sizeof(u64);
7395 header->size += size;
7398 if (sample_type & PERF_SAMPLE_STACK_USER) {
7400 * Either we need PERF_SAMPLE_STACK_USER bit to be always
7401 * processed as the last one or have additional check added
7402 * in case new sample type is added, because we could eat
7403 * up the rest of the sample size.
7405 u16 stack_size = event->attr.sample_stack_user;
7406 u16 size = sizeof(u64);
7408 stack_size = perf_sample_ustack_size(stack_size, header->size,
7409 data->regs_user.regs);
7412 * If there is something to dump, add space for the dump
7413 * itself and for the field that tells the dynamic size,
7414 * which is how many have been actually dumped.
7417 size += sizeof(u64) + stack_size;
7419 data->stack_user_size = stack_size;
7420 header->size += size;
7423 if (sample_type & PERF_SAMPLE_REGS_INTR) {
7424 /* regs dump ABI info */
7425 int size = sizeof(u64);
7427 perf_sample_regs_intr(&data->regs_intr, regs);
7429 if (data->regs_intr.regs) {
7430 u64 mask = event->attr.sample_regs_intr;
7432 size += hweight64(mask) * sizeof(u64);
7435 header->size += size;
7438 if (sample_type & PERF_SAMPLE_PHYS_ADDR)
7439 data->phys_addr = perf_virt_to_phys(data->addr);
7441 #ifdef CONFIG_CGROUP_PERF
7442 if (sample_type & PERF_SAMPLE_CGROUP) {
7443 struct cgroup *cgrp;
7445 /* protected by RCU */
7446 cgrp = task_css_check(current, perf_event_cgrp_id, 1)->cgroup;
7447 data->cgroup = cgroup_id(cgrp);
7452 * PERF_DATA_PAGE_SIZE requires PERF_SAMPLE_ADDR. If the user doesn't
7453 * require PERF_SAMPLE_ADDR, kernel implicitly retrieve the data->addr,
7454 * but the value will not dump to the userspace.
7456 if (sample_type & PERF_SAMPLE_DATA_PAGE_SIZE)
7457 data->data_page_size = perf_get_page_size(data->addr);
7459 if (sample_type & PERF_SAMPLE_CODE_PAGE_SIZE)
7460 data->code_page_size = perf_get_page_size(data->ip);
7462 if (sample_type & PERF_SAMPLE_AUX) {
7465 header->size += sizeof(u64); /* size */
7468 * Given the 16bit nature of header::size, an AUX sample can
7469 * easily overflow it, what with all the preceding sample bits.
7470 * Make sure this doesn't happen by using up to U16_MAX bytes
7471 * per sample in total (rounded down to 8 byte boundary).
7473 size = min_t(size_t, U16_MAX - header->size,
7474 event->attr.aux_sample_size);
7475 size = rounddown(size, 8);
7476 size = perf_prepare_sample_aux(event, data, size);
7478 WARN_ON_ONCE(size + header->size > U16_MAX);
7479 header->size += size;
7482 * If you're adding more sample types here, you likely need to do
7483 * something about the overflowing header::size, like repurpose the
7484 * lowest 3 bits of size, which should be always zero at the moment.
7485 * This raises a more important question, do we really need 512k sized
7486 * samples and why, so good argumentation is in order for whatever you
7489 WARN_ON_ONCE(header->size & 7);
7492 static __always_inline int
7493 __perf_event_output(struct perf_event *event,
7494 struct perf_sample_data *data,
7495 struct pt_regs *regs,
7496 int (*output_begin)(struct perf_output_handle *,
7497 struct perf_sample_data *,
7498 struct perf_event *,
7501 struct perf_output_handle handle;
7502 struct perf_event_header header;
7505 /* protect the callchain buffers */
7508 perf_prepare_sample(&header, data, event, regs);
7510 err = output_begin(&handle, data, event, header.size);
7514 perf_output_sample(&handle, &header, data, event);
7516 perf_output_end(&handle);
7524 perf_event_output_forward(struct perf_event *event,
7525 struct perf_sample_data *data,
7526 struct pt_regs *regs)
7528 __perf_event_output(event, data, regs, perf_output_begin_forward);
7532 perf_event_output_backward(struct perf_event *event,
7533 struct perf_sample_data *data,
7534 struct pt_regs *regs)
7536 __perf_event_output(event, data, regs, perf_output_begin_backward);
7540 perf_event_output(struct perf_event *event,
7541 struct perf_sample_data *data,
7542 struct pt_regs *regs)
7544 return __perf_event_output(event, data, regs, perf_output_begin);
7551 struct perf_read_event {
7552 struct perf_event_header header;
7559 perf_event_read_event(struct perf_event *event,
7560 struct task_struct *task)
7562 struct perf_output_handle handle;
7563 struct perf_sample_data sample;
7564 struct perf_read_event read_event = {
7566 .type = PERF_RECORD_READ,
7568 .size = sizeof(read_event) + event->read_size,
7570 .pid = perf_event_pid(event, task),
7571 .tid = perf_event_tid(event, task),
7575 perf_event_header__init_id(&read_event.header, &sample, event);
7576 ret = perf_output_begin(&handle, &sample, event, read_event.header.size);
7580 perf_output_put(&handle, read_event);
7581 perf_output_read(&handle, event);
7582 perf_event__output_id_sample(event, &handle, &sample);
7584 perf_output_end(&handle);
7587 typedef void (perf_iterate_f)(struct perf_event *event, void *data);
7590 perf_iterate_ctx(struct perf_event_context *ctx,
7591 perf_iterate_f output,
7592 void *data, bool all)
7594 struct perf_event *event;
7596 list_for_each_entry_rcu(event, &ctx->event_list, event_entry) {
7598 if (event->state < PERF_EVENT_STATE_INACTIVE)
7600 if (!event_filter_match(event))
7604 output(event, data);
7608 static void perf_iterate_sb_cpu(perf_iterate_f output, void *data)
7610 struct pmu_event_list *pel = this_cpu_ptr(&pmu_sb_events);
7611 struct perf_event *event;
7613 list_for_each_entry_rcu(event, &pel->list, sb_list) {
7615 * Skip events that are not fully formed yet; ensure that
7616 * if we observe event->ctx, both event and ctx will be
7617 * complete enough. See perf_install_in_context().
7619 if (!smp_load_acquire(&event->ctx))
7622 if (event->state < PERF_EVENT_STATE_INACTIVE)
7624 if (!event_filter_match(event))
7626 output(event, data);
7631 * Iterate all events that need to receive side-band events.
7633 * For new callers; ensure that account_pmu_sb_event() includes
7634 * your event, otherwise it might not get delivered.
7637 perf_iterate_sb(perf_iterate_f output, void *data,
7638 struct perf_event_context *task_ctx)
7640 struct perf_event_context *ctx;
7647 * If we have task_ctx != NULL we only notify the task context itself.
7648 * The task_ctx is set only for EXIT events before releasing task
7652 perf_iterate_ctx(task_ctx, output, data, false);
7656 perf_iterate_sb_cpu(output, data);
7658 for_each_task_context_nr(ctxn) {
7659 ctx = rcu_dereference(current->perf_event_ctxp[ctxn]);
7661 perf_iterate_ctx(ctx, output, data, false);
7669 * Clear all file-based filters at exec, they'll have to be
7670 * re-instated when/if these objects are mmapped again.
7672 static void perf_event_addr_filters_exec(struct perf_event *event, void *data)
7674 struct perf_addr_filters_head *ifh = perf_event_addr_filters(event);
7675 struct perf_addr_filter *filter;
7676 unsigned int restart = 0, count = 0;
7677 unsigned long flags;
7679 if (!has_addr_filter(event))
7682 raw_spin_lock_irqsave(&ifh->lock, flags);
7683 list_for_each_entry(filter, &ifh->list, entry) {
7684 if (filter->path.dentry) {
7685 event->addr_filter_ranges[count].start = 0;
7686 event->addr_filter_ranges[count].size = 0;
7694 event->addr_filters_gen++;
7695 raw_spin_unlock_irqrestore(&ifh->lock, flags);
7698 perf_event_stop(event, 1);
7701 void perf_event_exec(void)
7703 struct perf_event_context *ctx;
7706 for_each_task_context_nr(ctxn) {
7707 perf_event_enable_on_exec(ctxn);
7708 perf_event_remove_on_exec(ctxn);
7711 ctx = rcu_dereference(current->perf_event_ctxp[ctxn]);
7713 perf_iterate_ctx(ctx, perf_event_addr_filters_exec,
7720 struct remote_output {
7721 struct perf_buffer *rb;
7725 static void __perf_event_output_stop(struct perf_event *event, void *data)
7727 struct perf_event *parent = event->parent;
7728 struct remote_output *ro = data;
7729 struct perf_buffer *rb = ro->rb;
7730 struct stop_event_data sd = {
7734 if (!has_aux(event))
7741 * In case of inheritance, it will be the parent that links to the
7742 * ring-buffer, but it will be the child that's actually using it.
7744 * We are using event::rb to determine if the event should be stopped,
7745 * however this may race with ring_buffer_attach() (through set_output),
7746 * which will make us skip the event that actually needs to be stopped.
7747 * So ring_buffer_attach() has to stop an aux event before re-assigning
7750 if (rcu_dereference(parent->rb) == rb)
7751 ro->err = __perf_event_stop(&sd);
7754 static int __perf_pmu_output_stop(void *info)
7756 struct perf_event *event = info;
7757 struct pmu *pmu = event->ctx->pmu;
7758 struct perf_cpu_context *cpuctx = this_cpu_ptr(pmu->pmu_cpu_context);
7759 struct remote_output ro = {
7764 perf_iterate_ctx(&cpuctx->ctx, __perf_event_output_stop, &ro, false);
7765 if (cpuctx->task_ctx)
7766 perf_iterate_ctx(cpuctx->task_ctx, __perf_event_output_stop,
7773 static void perf_pmu_output_stop(struct perf_event *event)
7775 struct perf_event *iter;
7780 list_for_each_entry_rcu(iter, &event->rb->event_list, rb_entry) {
7782 * For per-CPU events, we need to make sure that neither they
7783 * nor their children are running; for cpu==-1 events it's
7784 * sufficient to stop the event itself if it's active, since
7785 * it can't have children.
7789 cpu = READ_ONCE(iter->oncpu);
7794 err = cpu_function_call(cpu, __perf_pmu_output_stop, event);
7795 if (err == -EAGAIN) {
7804 * task tracking -- fork/exit
7806 * enabled by: attr.comm | attr.mmap | attr.mmap2 | attr.mmap_data | attr.task
7809 struct perf_task_event {
7810 struct task_struct *task;
7811 struct perf_event_context *task_ctx;
7814 struct perf_event_header header;
7824 static int perf_event_task_match(struct perf_event *event)
7826 return event->attr.comm || event->attr.mmap ||
7827 event->attr.mmap2 || event->attr.mmap_data ||
7831 static void perf_event_task_output(struct perf_event *event,
7834 struct perf_task_event *task_event = data;
7835 struct perf_output_handle handle;
7836 struct perf_sample_data sample;
7837 struct task_struct *task = task_event->task;
7838 int ret, size = task_event->event_id.header.size;
7840 if (!perf_event_task_match(event))
7843 perf_event_header__init_id(&task_event->event_id.header, &sample, event);
7845 ret = perf_output_begin(&handle, &sample, event,
7846 task_event->event_id.header.size);
7850 task_event->event_id.pid = perf_event_pid(event, task);
7851 task_event->event_id.tid = perf_event_tid(event, task);
7853 if (task_event->event_id.header.type == PERF_RECORD_EXIT) {
7854 task_event->event_id.ppid = perf_event_pid(event,
7856 task_event->event_id.ptid = perf_event_pid(event,
7858 } else { /* PERF_RECORD_FORK */
7859 task_event->event_id.ppid = perf_event_pid(event, current);
7860 task_event->event_id.ptid = perf_event_tid(event, current);
7863 task_event->event_id.time = perf_event_clock(event);
7865 perf_output_put(&handle, task_event->event_id);
7867 perf_event__output_id_sample(event, &handle, &sample);
7869 perf_output_end(&handle);
7871 task_event->event_id.header.size = size;
7874 static void perf_event_task(struct task_struct *task,
7875 struct perf_event_context *task_ctx,
7878 struct perf_task_event task_event;
7880 if (!atomic_read(&nr_comm_events) &&
7881 !atomic_read(&nr_mmap_events) &&
7882 !atomic_read(&nr_task_events))
7885 task_event = (struct perf_task_event){
7887 .task_ctx = task_ctx,
7890 .type = new ? PERF_RECORD_FORK : PERF_RECORD_EXIT,
7892 .size = sizeof(task_event.event_id),
7902 perf_iterate_sb(perf_event_task_output,
7907 void perf_event_fork(struct task_struct *task)
7909 perf_event_task(task, NULL, 1);
7910 perf_event_namespaces(task);
7917 struct perf_comm_event {
7918 struct task_struct *task;
7923 struct perf_event_header header;
7930 static int perf_event_comm_match(struct perf_event *event)
7932 return event->attr.comm;
7935 static void perf_event_comm_output(struct perf_event *event,
7938 struct perf_comm_event *comm_event = data;
7939 struct perf_output_handle handle;
7940 struct perf_sample_data sample;
7941 int size = comm_event->event_id.header.size;
7944 if (!perf_event_comm_match(event))
7947 perf_event_header__init_id(&comm_event->event_id.header, &sample, event);
7948 ret = perf_output_begin(&handle, &sample, event,
7949 comm_event->event_id.header.size);
7954 comm_event->event_id.pid = perf_event_pid(event, comm_event->task);
7955 comm_event->event_id.tid = perf_event_tid(event, comm_event->task);
7957 perf_output_put(&handle, comm_event->event_id);
7958 __output_copy(&handle, comm_event->comm,
7959 comm_event->comm_size);
7961 perf_event__output_id_sample(event, &handle, &sample);
7963 perf_output_end(&handle);
7965 comm_event->event_id.header.size = size;
7968 static void perf_event_comm_event(struct perf_comm_event *comm_event)
7970 char comm[TASK_COMM_LEN];
7973 memset(comm, 0, sizeof(comm));
7974 strlcpy(comm, comm_event->task->comm, sizeof(comm));
7975 size = ALIGN(strlen(comm)+1, sizeof(u64));
7977 comm_event->comm = comm;
7978 comm_event->comm_size = size;
7980 comm_event->event_id.header.size = sizeof(comm_event->event_id) + size;
7982 perf_iterate_sb(perf_event_comm_output,
7987 void perf_event_comm(struct task_struct *task, bool exec)
7989 struct perf_comm_event comm_event;
7991 if (!atomic_read(&nr_comm_events))
7994 comm_event = (struct perf_comm_event){
8000 .type = PERF_RECORD_COMM,
8001 .misc = exec ? PERF_RECORD_MISC_COMM_EXEC : 0,
8009 perf_event_comm_event(&comm_event);
8013 * namespaces tracking
8016 struct perf_namespaces_event {
8017 struct task_struct *task;
8020 struct perf_event_header header;
8025 struct perf_ns_link_info link_info[NR_NAMESPACES];
8029 static int perf_event_namespaces_match(struct perf_event *event)
8031 return event->attr.namespaces;
8034 static void perf_event_namespaces_output(struct perf_event *event,
8037 struct perf_namespaces_event *namespaces_event = data;
8038 struct perf_output_handle handle;
8039 struct perf_sample_data sample;
8040 u16 header_size = namespaces_event->event_id.header.size;
8043 if (!perf_event_namespaces_match(event))
8046 perf_event_header__init_id(&namespaces_event->event_id.header,
8048 ret = perf_output_begin(&handle, &sample, event,
8049 namespaces_event->event_id.header.size);
8053 namespaces_event->event_id.pid = perf_event_pid(event,
8054 namespaces_event->task);
8055 namespaces_event->event_id.tid = perf_event_tid(event,
8056 namespaces_event->task);
8058 perf_output_put(&handle, namespaces_event->event_id);
8060 perf_event__output_id_sample(event, &handle, &sample);
8062 perf_output_end(&handle);
8064 namespaces_event->event_id.header.size = header_size;
8067 static void perf_fill_ns_link_info(struct perf_ns_link_info *ns_link_info,
8068 struct task_struct *task,
8069 const struct proc_ns_operations *ns_ops)
8071 struct path ns_path;
8072 struct inode *ns_inode;
8075 error = ns_get_path(&ns_path, task, ns_ops);
8077 ns_inode = ns_path.dentry->d_inode;
8078 ns_link_info->dev = new_encode_dev(ns_inode->i_sb->s_dev);
8079 ns_link_info->ino = ns_inode->i_ino;
8084 void perf_event_namespaces(struct task_struct *task)
8086 struct perf_namespaces_event namespaces_event;
8087 struct perf_ns_link_info *ns_link_info;
8089 if (!atomic_read(&nr_namespaces_events))
8092 namespaces_event = (struct perf_namespaces_event){
8096 .type = PERF_RECORD_NAMESPACES,
8098 .size = sizeof(namespaces_event.event_id),
8102 .nr_namespaces = NR_NAMESPACES,
8103 /* .link_info[NR_NAMESPACES] */
8107 ns_link_info = namespaces_event.event_id.link_info;
8109 perf_fill_ns_link_info(&ns_link_info[MNT_NS_INDEX],
8110 task, &mntns_operations);
8112 #ifdef CONFIG_USER_NS
8113 perf_fill_ns_link_info(&ns_link_info[USER_NS_INDEX],
8114 task, &userns_operations);
8116 #ifdef CONFIG_NET_NS
8117 perf_fill_ns_link_info(&ns_link_info[NET_NS_INDEX],
8118 task, &netns_operations);
8120 #ifdef CONFIG_UTS_NS
8121 perf_fill_ns_link_info(&ns_link_info[UTS_NS_INDEX],
8122 task, &utsns_operations);
8124 #ifdef CONFIG_IPC_NS
8125 perf_fill_ns_link_info(&ns_link_info[IPC_NS_INDEX],
8126 task, &ipcns_operations);
8128 #ifdef CONFIG_PID_NS
8129 perf_fill_ns_link_info(&ns_link_info[PID_NS_INDEX],
8130 task, &pidns_operations);
8132 #ifdef CONFIG_CGROUPS
8133 perf_fill_ns_link_info(&ns_link_info[CGROUP_NS_INDEX],
8134 task, &cgroupns_operations);
8137 perf_iterate_sb(perf_event_namespaces_output,
8145 #ifdef CONFIG_CGROUP_PERF
8147 struct perf_cgroup_event {
8151 struct perf_event_header header;
8157 static int perf_event_cgroup_match(struct perf_event *event)
8159 return event->attr.cgroup;
8162 static void perf_event_cgroup_output(struct perf_event *event, void *data)
8164 struct perf_cgroup_event *cgroup_event = data;
8165 struct perf_output_handle handle;
8166 struct perf_sample_data sample;
8167 u16 header_size = cgroup_event->event_id.header.size;
8170 if (!perf_event_cgroup_match(event))
8173 perf_event_header__init_id(&cgroup_event->event_id.header,
8175 ret = perf_output_begin(&handle, &sample, event,
8176 cgroup_event->event_id.header.size);
8180 perf_output_put(&handle, cgroup_event->event_id);
8181 __output_copy(&handle, cgroup_event->path, cgroup_event->path_size);
8183 perf_event__output_id_sample(event, &handle, &sample);
8185 perf_output_end(&handle);
8187 cgroup_event->event_id.header.size = header_size;
8190 static void perf_event_cgroup(struct cgroup *cgrp)
8192 struct perf_cgroup_event cgroup_event;
8193 char path_enomem[16] = "//enomem";
8197 if (!atomic_read(&nr_cgroup_events))
8200 cgroup_event = (struct perf_cgroup_event){
8203 .type = PERF_RECORD_CGROUP,
8205 .size = sizeof(cgroup_event.event_id),
8207 .id = cgroup_id(cgrp),
8211 pathname = kmalloc(PATH_MAX, GFP_KERNEL);
8212 if (pathname == NULL) {
8213 cgroup_event.path = path_enomem;
8215 /* just to be sure to have enough space for alignment */
8216 cgroup_path(cgrp, pathname, PATH_MAX - sizeof(u64));
8217 cgroup_event.path = pathname;
8221 * Since our buffer works in 8 byte units we need to align our string
8222 * size to a multiple of 8. However, we must guarantee the tail end is
8223 * zero'd out to avoid leaking random bits to userspace.
8225 size = strlen(cgroup_event.path) + 1;
8226 while (!IS_ALIGNED(size, sizeof(u64)))
8227 cgroup_event.path[size++] = '\0';
8229 cgroup_event.event_id.header.size += size;
8230 cgroup_event.path_size = size;
8232 perf_iterate_sb(perf_event_cgroup_output,
8245 struct perf_mmap_event {
8246 struct vm_area_struct *vma;
8248 const char *file_name;
8254 u8 build_id[BUILD_ID_SIZE_MAX];
8258 struct perf_event_header header;
8268 static int perf_event_mmap_match(struct perf_event *event,
8271 struct perf_mmap_event *mmap_event = data;
8272 struct vm_area_struct *vma = mmap_event->vma;
8273 int executable = vma->vm_flags & VM_EXEC;
8275 return (!executable && event->attr.mmap_data) ||
8276 (executable && (event->attr.mmap || event->attr.mmap2));
8279 static void perf_event_mmap_output(struct perf_event *event,
8282 struct perf_mmap_event *mmap_event = data;
8283 struct perf_output_handle handle;
8284 struct perf_sample_data sample;
8285 int size = mmap_event->event_id.header.size;
8286 u32 type = mmap_event->event_id.header.type;
8290 if (!perf_event_mmap_match(event, data))
8293 if (event->attr.mmap2) {
8294 mmap_event->event_id.header.type = PERF_RECORD_MMAP2;
8295 mmap_event->event_id.header.size += sizeof(mmap_event->maj);
8296 mmap_event->event_id.header.size += sizeof(mmap_event->min);
8297 mmap_event->event_id.header.size += sizeof(mmap_event->ino);
8298 mmap_event->event_id.header.size += sizeof(mmap_event->ino_generation);
8299 mmap_event->event_id.header.size += sizeof(mmap_event->prot);
8300 mmap_event->event_id.header.size += sizeof(mmap_event->flags);
8303 perf_event_header__init_id(&mmap_event->event_id.header, &sample, event);
8304 ret = perf_output_begin(&handle, &sample, event,
8305 mmap_event->event_id.header.size);
8309 mmap_event->event_id.pid = perf_event_pid(event, current);
8310 mmap_event->event_id.tid = perf_event_tid(event, current);
8312 use_build_id = event->attr.build_id && mmap_event->build_id_size;
8314 if (event->attr.mmap2 && use_build_id)
8315 mmap_event->event_id.header.misc |= PERF_RECORD_MISC_MMAP_BUILD_ID;
8317 perf_output_put(&handle, mmap_event->event_id);
8319 if (event->attr.mmap2) {
8321 u8 size[4] = { (u8) mmap_event->build_id_size, 0, 0, 0 };
8323 __output_copy(&handle, size, 4);
8324 __output_copy(&handle, mmap_event->build_id, BUILD_ID_SIZE_MAX);
8326 perf_output_put(&handle, mmap_event->maj);
8327 perf_output_put(&handle, mmap_event->min);
8328 perf_output_put(&handle, mmap_event->ino);
8329 perf_output_put(&handle, mmap_event->ino_generation);
8331 perf_output_put(&handle, mmap_event->prot);
8332 perf_output_put(&handle, mmap_event->flags);
8335 __output_copy(&handle, mmap_event->file_name,
8336 mmap_event->file_size);
8338 perf_event__output_id_sample(event, &handle, &sample);
8340 perf_output_end(&handle);
8342 mmap_event->event_id.header.size = size;
8343 mmap_event->event_id.header.type = type;
8346 static void perf_event_mmap_event(struct perf_mmap_event *mmap_event)
8348 struct vm_area_struct *vma = mmap_event->vma;
8349 struct file *file = vma->vm_file;
8350 int maj = 0, min = 0;
8351 u64 ino = 0, gen = 0;
8352 u32 prot = 0, flags = 0;
8358 if (vma->vm_flags & VM_READ)
8360 if (vma->vm_flags & VM_WRITE)
8362 if (vma->vm_flags & VM_EXEC)
8365 if (vma->vm_flags & VM_MAYSHARE)
8368 flags = MAP_PRIVATE;
8370 if (vma->vm_flags & VM_LOCKED)
8371 flags |= MAP_LOCKED;
8372 if (is_vm_hugetlb_page(vma))
8373 flags |= MAP_HUGETLB;
8376 struct inode *inode;
8379 buf = kmalloc(PATH_MAX, GFP_KERNEL);
8385 * d_path() works from the end of the rb backwards, so we
8386 * need to add enough zero bytes after the string to handle
8387 * the 64bit alignment we do later.
8389 name = file_path(file, buf, PATH_MAX - sizeof(u64));
8394 inode = file_inode(vma->vm_file);
8395 dev = inode->i_sb->s_dev;
8397 gen = inode->i_generation;
8403 if (vma->vm_ops && vma->vm_ops->name) {
8404 name = (char *) vma->vm_ops->name(vma);
8409 name = (char *)arch_vma_name(vma);
8413 if (vma->vm_start <= vma->vm_mm->start_brk &&
8414 vma->vm_end >= vma->vm_mm->brk) {
8418 if (vma->vm_start <= vma->vm_mm->start_stack &&
8419 vma->vm_end >= vma->vm_mm->start_stack) {
8429 strlcpy(tmp, name, sizeof(tmp));
8433 * Since our buffer works in 8 byte units we need to align our string
8434 * size to a multiple of 8. However, we must guarantee the tail end is
8435 * zero'd out to avoid leaking random bits to userspace.
8437 size = strlen(name)+1;
8438 while (!IS_ALIGNED(size, sizeof(u64)))
8439 name[size++] = '\0';
8441 mmap_event->file_name = name;
8442 mmap_event->file_size = size;
8443 mmap_event->maj = maj;
8444 mmap_event->min = min;
8445 mmap_event->ino = ino;
8446 mmap_event->ino_generation = gen;
8447 mmap_event->prot = prot;
8448 mmap_event->flags = flags;
8450 if (!(vma->vm_flags & VM_EXEC))
8451 mmap_event->event_id.header.misc |= PERF_RECORD_MISC_MMAP_DATA;
8453 mmap_event->event_id.header.size = sizeof(mmap_event->event_id) + size;
8455 if (atomic_read(&nr_build_id_events))
8456 build_id_parse(vma, mmap_event->build_id, &mmap_event->build_id_size);
8458 perf_iterate_sb(perf_event_mmap_output,
8466 * Check whether inode and address range match filter criteria.
8468 static bool perf_addr_filter_match(struct perf_addr_filter *filter,
8469 struct file *file, unsigned long offset,
8472 /* d_inode(NULL) won't be equal to any mapped user-space file */
8473 if (!filter->path.dentry)
8476 if (d_inode(filter->path.dentry) != file_inode(file))
8479 if (filter->offset > offset + size)
8482 if (filter->offset + filter->size < offset)
8488 static bool perf_addr_filter_vma_adjust(struct perf_addr_filter *filter,
8489 struct vm_area_struct *vma,
8490 struct perf_addr_filter_range *fr)
8492 unsigned long vma_size = vma->vm_end - vma->vm_start;
8493 unsigned long off = vma->vm_pgoff << PAGE_SHIFT;
8494 struct file *file = vma->vm_file;
8496 if (!perf_addr_filter_match(filter, file, off, vma_size))
8499 if (filter->offset < off) {
8500 fr->start = vma->vm_start;
8501 fr->size = min(vma_size, filter->size - (off - filter->offset));
8503 fr->start = vma->vm_start + filter->offset - off;
8504 fr->size = min(vma->vm_end - fr->start, filter->size);
8510 static void __perf_addr_filters_adjust(struct perf_event *event, void *data)
8512 struct perf_addr_filters_head *ifh = perf_event_addr_filters(event);
8513 struct vm_area_struct *vma = data;
8514 struct perf_addr_filter *filter;
8515 unsigned int restart = 0, count = 0;
8516 unsigned long flags;
8518 if (!has_addr_filter(event))
8524 raw_spin_lock_irqsave(&ifh->lock, flags);
8525 list_for_each_entry(filter, &ifh->list, entry) {
8526 if (perf_addr_filter_vma_adjust(filter, vma,
8527 &event->addr_filter_ranges[count]))
8534 event->addr_filters_gen++;
8535 raw_spin_unlock_irqrestore(&ifh->lock, flags);
8538 perf_event_stop(event, 1);
8542 * Adjust all task's events' filters to the new vma
8544 static void perf_addr_filters_adjust(struct vm_area_struct *vma)
8546 struct perf_event_context *ctx;
8550 * Data tracing isn't supported yet and as such there is no need
8551 * to keep track of anything that isn't related to executable code:
8553 if (!(vma->vm_flags & VM_EXEC))
8557 for_each_task_context_nr(ctxn) {
8558 ctx = rcu_dereference(current->perf_event_ctxp[ctxn]);
8562 perf_iterate_ctx(ctx, __perf_addr_filters_adjust, vma, true);
8567 void perf_event_mmap(struct vm_area_struct *vma)
8569 struct perf_mmap_event mmap_event;
8571 if (!atomic_read(&nr_mmap_events))
8574 mmap_event = (struct perf_mmap_event){
8580 .type = PERF_RECORD_MMAP,
8581 .misc = PERF_RECORD_MISC_USER,
8586 .start = vma->vm_start,
8587 .len = vma->vm_end - vma->vm_start,
8588 .pgoff = (u64)vma->vm_pgoff << PAGE_SHIFT,
8590 /* .maj (attr_mmap2 only) */
8591 /* .min (attr_mmap2 only) */
8592 /* .ino (attr_mmap2 only) */
8593 /* .ino_generation (attr_mmap2 only) */
8594 /* .prot (attr_mmap2 only) */
8595 /* .flags (attr_mmap2 only) */
8598 perf_addr_filters_adjust(vma);
8599 perf_event_mmap_event(&mmap_event);
8602 void perf_event_aux_event(struct perf_event *event, unsigned long head,
8603 unsigned long size, u64 flags)
8605 struct perf_output_handle handle;
8606 struct perf_sample_data sample;
8607 struct perf_aux_event {
8608 struct perf_event_header header;
8614 .type = PERF_RECORD_AUX,
8616 .size = sizeof(rec),
8624 perf_event_header__init_id(&rec.header, &sample, event);
8625 ret = perf_output_begin(&handle, &sample, event, rec.header.size);
8630 perf_output_put(&handle, rec);
8631 perf_event__output_id_sample(event, &handle, &sample);
8633 perf_output_end(&handle);
8637 * Lost/dropped samples logging
8639 void perf_log_lost_samples(struct perf_event *event, u64 lost)
8641 struct perf_output_handle handle;
8642 struct perf_sample_data sample;
8646 struct perf_event_header header;
8648 } lost_samples_event = {
8650 .type = PERF_RECORD_LOST_SAMPLES,
8652 .size = sizeof(lost_samples_event),
8657 perf_event_header__init_id(&lost_samples_event.header, &sample, event);
8659 ret = perf_output_begin(&handle, &sample, event,
8660 lost_samples_event.header.size);
8664 perf_output_put(&handle, lost_samples_event);
8665 perf_event__output_id_sample(event, &handle, &sample);
8666 perf_output_end(&handle);
8670 * context_switch tracking
8673 struct perf_switch_event {
8674 struct task_struct *task;
8675 struct task_struct *next_prev;
8678 struct perf_event_header header;
8684 static int perf_event_switch_match(struct perf_event *event)
8686 return event->attr.context_switch;
8689 static void perf_event_switch_output(struct perf_event *event, void *data)
8691 struct perf_switch_event *se = data;
8692 struct perf_output_handle handle;
8693 struct perf_sample_data sample;
8696 if (!perf_event_switch_match(event))
8699 /* Only CPU-wide events are allowed to see next/prev pid/tid */
8700 if (event->ctx->task) {
8701 se->event_id.header.type = PERF_RECORD_SWITCH;
8702 se->event_id.header.size = sizeof(se->event_id.header);
8704 se->event_id.header.type = PERF_RECORD_SWITCH_CPU_WIDE;
8705 se->event_id.header.size = sizeof(se->event_id);
8706 se->event_id.next_prev_pid =
8707 perf_event_pid(event, se->next_prev);
8708 se->event_id.next_prev_tid =
8709 perf_event_tid(event, se->next_prev);
8712 perf_event_header__init_id(&se->event_id.header, &sample, event);
8714 ret = perf_output_begin(&handle, &sample, event, se->event_id.header.size);
8718 if (event->ctx->task)
8719 perf_output_put(&handle, se->event_id.header);
8721 perf_output_put(&handle, se->event_id);
8723 perf_event__output_id_sample(event, &handle, &sample);
8725 perf_output_end(&handle);
8728 static void perf_event_switch(struct task_struct *task,
8729 struct task_struct *next_prev, bool sched_in)
8731 struct perf_switch_event switch_event;
8733 /* N.B. caller checks nr_switch_events != 0 */
8735 switch_event = (struct perf_switch_event){
8737 .next_prev = next_prev,
8741 .misc = sched_in ? 0 : PERF_RECORD_MISC_SWITCH_OUT,
8744 /* .next_prev_pid */
8745 /* .next_prev_tid */
8749 if (!sched_in && task->on_rq) {
8750 switch_event.event_id.header.misc |=
8751 PERF_RECORD_MISC_SWITCH_OUT_PREEMPT;
8754 perf_iterate_sb(perf_event_switch_output, &switch_event, NULL);
8758 * IRQ throttle logging
8761 static void perf_log_throttle(struct perf_event *event, int enable)
8763 struct perf_output_handle handle;
8764 struct perf_sample_data sample;
8768 struct perf_event_header header;
8772 } throttle_event = {
8774 .type = PERF_RECORD_THROTTLE,
8776 .size = sizeof(throttle_event),
8778 .time = perf_event_clock(event),
8779 .id = primary_event_id(event),
8780 .stream_id = event->id,
8784 throttle_event.header.type = PERF_RECORD_UNTHROTTLE;
8786 perf_event_header__init_id(&throttle_event.header, &sample, event);
8788 ret = perf_output_begin(&handle, &sample, event,
8789 throttle_event.header.size);
8793 perf_output_put(&handle, throttle_event);
8794 perf_event__output_id_sample(event, &handle, &sample);
8795 perf_output_end(&handle);
8799 * ksymbol register/unregister tracking
8802 struct perf_ksymbol_event {
8806 struct perf_event_header header;
8814 static int perf_event_ksymbol_match(struct perf_event *event)
8816 return event->attr.ksymbol;
8819 static void perf_event_ksymbol_output(struct perf_event *event, void *data)
8821 struct perf_ksymbol_event *ksymbol_event = data;
8822 struct perf_output_handle handle;
8823 struct perf_sample_data sample;
8826 if (!perf_event_ksymbol_match(event))
8829 perf_event_header__init_id(&ksymbol_event->event_id.header,
8831 ret = perf_output_begin(&handle, &sample, event,
8832 ksymbol_event->event_id.header.size);
8836 perf_output_put(&handle, ksymbol_event->event_id);
8837 __output_copy(&handle, ksymbol_event->name, ksymbol_event->name_len);
8838 perf_event__output_id_sample(event, &handle, &sample);
8840 perf_output_end(&handle);
8843 void perf_event_ksymbol(u16 ksym_type, u64 addr, u32 len, bool unregister,
8846 struct perf_ksymbol_event ksymbol_event;
8847 char name[KSYM_NAME_LEN];
8851 if (!atomic_read(&nr_ksymbol_events))
8854 if (ksym_type >= PERF_RECORD_KSYMBOL_TYPE_MAX ||
8855 ksym_type == PERF_RECORD_KSYMBOL_TYPE_UNKNOWN)
8858 strlcpy(name, sym, KSYM_NAME_LEN);
8859 name_len = strlen(name) + 1;
8860 while (!IS_ALIGNED(name_len, sizeof(u64)))
8861 name[name_len++] = '\0';
8862 BUILD_BUG_ON(KSYM_NAME_LEN % sizeof(u64));
8865 flags |= PERF_RECORD_KSYMBOL_FLAGS_UNREGISTER;
8867 ksymbol_event = (struct perf_ksymbol_event){
8869 .name_len = name_len,
8872 .type = PERF_RECORD_KSYMBOL,
8873 .size = sizeof(ksymbol_event.event_id) +
8878 .ksym_type = ksym_type,
8883 perf_iterate_sb(perf_event_ksymbol_output, &ksymbol_event, NULL);
8886 WARN_ONCE(1, "%s: Invalid KSYMBOL type 0x%x\n", __func__, ksym_type);
8890 * bpf program load/unload tracking
8893 struct perf_bpf_event {
8894 struct bpf_prog *prog;
8896 struct perf_event_header header;
8900 u8 tag[BPF_TAG_SIZE];
8904 static int perf_event_bpf_match(struct perf_event *event)
8906 return event->attr.bpf_event;
8909 static void perf_event_bpf_output(struct perf_event *event, void *data)
8911 struct perf_bpf_event *bpf_event = data;
8912 struct perf_output_handle handle;
8913 struct perf_sample_data sample;
8916 if (!perf_event_bpf_match(event))
8919 perf_event_header__init_id(&bpf_event->event_id.header,
8921 ret = perf_output_begin(&handle, data, event,
8922 bpf_event->event_id.header.size);
8926 perf_output_put(&handle, bpf_event->event_id);
8927 perf_event__output_id_sample(event, &handle, &sample);
8929 perf_output_end(&handle);
8932 static void perf_event_bpf_emit_ksymbols(struct bpf_prog *prog,
8933 enum perf_bpf_event_type type)
8935 bool unregister = type == PERF_BPF_EVENT_PROG_UNLOAD;
8938 if (prog->aux->func_cnt == 0) {
8939 perf_event_ksymbol(PERF_RECORD_KSYMBOL_TYPE_BPF,
8940 (u64)(unsigned long)prog->bpf_func,
8941 prog->jited_len, unregister,
8942 prog->aux->ksym.name);
8944 for (i = 0; i < prog->aux->func_cnt; i++) {
8945 struct bpf_prog *subprog = prog->aux->func[i];
8948 PERF_RECORD_KSYMBOL_TYPE_BPF,
8949 (u64)(unsigned long)subprog->bpf_func,
8950 subprog->jited_len, unregister,
8951 prog->aux->ksym.name);
8956 void perf_event_bpf_event(struct bpf_prog *prog,
8957 enum perf_bpf_event_type type,
8960 struct perf_bpf_event bpf_event;
8962 if (type <= PERF_BPF_EVENT_UNKNOWN ||
8963 type >= PERF_BPF_EVENT_MAX)
8967 case PERF_BPF_EVENT_PROG_LOAD:
8968 case PERF_BPF_EVENT_PROG_UNLOAD:
8969 if (atomic_read(&nr_ksymbol_events))
8970 perf_event_bpf_emit_ksymbols(prog, type);
8976 if (!atomic_read(&nr_bpf_events))
8979 bpf_event = (struct perf_bpf_event){
8983 .type = PERF_RECORD_BPF_EVENT,
8984 .size = sizeof(bpf_event.event_id),
8988 .id = prog->aux->id,
8992 BUILD_BUG_ON(BPF_TAG_SIZE % sizeof(u64));
8994 memcpy(bpf_event.event_id.tag, prog->tag, BPF_TAG_SIZE);
8995 perf_iterate_sb(perf_event_bpf_output, &bpf_event, NULL);
8998 struct perf_text_poke_event {
8999 const void *old_bytes;
9000 const void *new_bytes;
9006 struct perf_event_header header;
9012 static int perf_event_text_poke_match(struct perf_event *event)
9014 return event->attr.text_poke;
9017 static void perf_event_text_poke_output(struct perf_event *event, void *data)
9019 struct perf_text_poke_event *text_poke_event = data;
9020 struct perf_output_handle handle;
9021 struct perf_sample_data sample;
9025 if (!perf_event_text_poke_match(event))
9028 perf_event_header__init_id(&text_poke_event->event_id.header, &sample, event);
9030 ret = perf_output_begin(&handle, &sample, event,
9031 text_poke_event->event_id.header.size);
9035 perf_output_put(&handle, text_poke_event->event_id);
9036 perf_output_put(&handle, text_poke_event->old_len);
9037 perf_output_put(&handle, text_poke_event->new_len);
9039 __output_copy(&handle, text_poke_event->old_bytes, text_poke_event->old_len);
9040 __output_copy(&handle, text_poke_event->new_bytes, text_poke_event->new_len);
9042 if (text_poke_event->pad)
9043 __output_copy(&handle, &padding, text_poke_event->pad);
9045 perf_event__output_id_sample(event, &handle, &sample);
9047 perf_output_end(&handle);
9050 void perf_event_text_poke(const void *addr, const void *old_bytes,
9051 size_t old_len, const void *new_bytes, size_t new_len)
9053 struct perf_text_poke_event text_poke_event;
9056 if (!atomic_read(&nr_text_poke_events))
9059 tot = sizeof(text_poke_event.old_len) + old_len;
9060 tot += sizeof(text_poke_event.new_len) + new_len;
9061 pad = ALIGN(tot, sizeof(u64)) - tot;
9063 text_poke_event = (struct perf_text_poke_event){
9064 .old_bytes = old_bytes,
9065 .new_bytes = new_bytes,
9071 .type = PERF_RECORD_TEXT_POKE,
9072 .misc = PERF_RECORD_MISC_KERNEL,
9073 .size = sizeof(text_poke_event.event_id) + tot + pad,
9075 .addr = (unsigned long)addr,
9079 perf_iterate_sb(perf_event_text_poke_output, &text_poke_event, NULL);
9082 void perf_event_itrace_started(struct perf_event *event)
9084 event->attach_state |= PERF_ATTACH_ITRACE;
9087 static void perf_log_itrace_start(struct perf_event *event)
9089 struct perf_output_handle handle;
9090 struct perf_sample_data sample;
9091 struct perf_aux_event {
9092 struct perf_event_header header;
9099 event = event->parent;
9101 if (!(event->pmu->capabilities & PERF_PMU_CAP_ITRACE) ||
9102 event->attach_state & PERF_ATTACH_ITRACE)
9105 rec.header.type = PERF_RECORD_ITRACE_START;
9106 rec.header.misc = 0;
9107 rec.header.size = sizeof(rec);
9108 rec.pid = perf_event_pid(event, current);
9109 rec.tid = perf_event_tid(event, current);
9111 perf_event_header__init_id(&rec.header, &sample, event);
9112 ret = perf_output_begin(&handle, &sample, event, rec.header.size);
9117 perf_output_put(&handle, rec);
9118 perf_event__output_id_sample(event, &handle, &sample);
9120 perf_output_end(&handle);
9123 void perf_report_aux_output_id(struct perf_event *event, u64 hw_id)
9125 struct perf_output_handle handle;
9126 struct perf_sample_data sample;
9127 struct perf_aux_event {
9128 struct perf_event_header header;
9134 event = event->parent;
9136 rec.header.type = PERF_RECORD_AUX_OUTPUT_HW_ID;
9137 rec.header.misc = 0;
9138 rec.header.size = sizeof(rec);
9141 perf_event_header__init_id(&rec.header, &sample, event);
9142 ret = perf_output_begin(&handle, &sample, event, rec.header.size);
9147 perf_output_put(&handle, rec);
9148 perf_event__output_id_sample(event, &handle, &sample);
9150 perf_output_end(&handle);
9154 __perf_event_account_interrupt(struct perf_event *event, int throttle)
9156 struct hw_perf_event *hwc = &event->hw;
9160 seq = __this_cpu_read(perf_throttled_seq);
9161 if (seq != hwc->interrupts_seq) {
9162 hwc->interrupts_seq = seq;
9163 hwc->interrupts = 1;
9166 if (unlikely(throttle
9167 && hwc->interrupts >= max_samples_per_tick)) {
9168 __this_cpu_inc(perf_throttled_count);
9169 tick_dep_set_cpu(smp_processor_id(), TICK_DEP_BIT_PERF_EVENTS);
9170 hwc->interrupts = MAX_INTERRUPTS;
9171 perf_log_throttle(event, 0);
9176 if (event->attr.freq) {
9177 u64 now = perf_clock();
9178 s64 delta = now - hwc->freq_time_stamp;
9180 hwc->freq_time_stamp = now;
9182 if (delta > 0 && delta < 2*TICK_NSEC)
9183 perf_adjust_period(event, delta, hwc->last_period, true);
9189 int perf_event_account_interrupt(struct perf_event *event)
9191 return __perf_event_account_interrupt(event, 1);
9195 * Generic event overflow handling, sampling.
9198 static int __perf_event_overflow(struct perf_event *event,
9199 int throttle, struct perf_sample_data *data,
9200 struct pt_regs *regs)
9202 int events = atomic_read(&event->event_limit);
9206 * Non-sampling counters might still use the PMI to fold short
9207 * hardware counters, ignore those.
9209 if (unlikely(!is_sampling_event(event)))
9212 ret = __perf_event_account_interrupt(event, throttle);
9215 * XXX event_limit might not quite work as expected on inherited
9219 event->pending_kill = POLL_IN;
9220 if (events && atomic_dec_and_test(&event->event_limit)) {
9222 event->pending_kill = POLL_HUP;
9223 event->pending_addr = data->addr;
9225 perf_event_disable_inatomic(event);
9228 READ_ONCE(event->overflow_handler)(event, data, regs);
9230 if (*perf_event_fasync(event) && event->pending_kill) {
9231 event->pending_wakeup = 1;
9232 irq_work_queue(&event->pending);
9238 int perf_event_overflow(struct perf_event *event,
9239 struct perf_sample_data *data,
9240 struct pt_regs *regs)
9242 return __perf_event_overflow(event, 1, data, regs);
9246 * Generic software event infrastructure
9249 struct swevent_htable {
9250 struct swevent_hlist *swevent_hlist;
9251 struct mutex hlist_mutex;
9254 /* Recursion avoidance in each contexts */
9255 int recursion[PERF_NR_CONTEXTS];
9258 static DEFINE_PER_CPU(struct swevent_htable, swevent_htable);
9261 * We directly increment event->count and keep a second value in
9262 * event->hw.period_left to count intervals. This period event
9263 * is kept in the range [-sample_period, 0] so that we can use the
9267 u64 perf_swevent_set_period(struct perf_event *event)
9269 struct hw_perf_event *hwc = &event->hw;
9270 u64 period = hwc->last_period;
9274 hwc->last_period = hwc->sample_period;
9277 old = val = local64_read(&hwc->period_left);
9281 nr = div64_u64(period + val, period);
9282 offset = nr * period;
9284 if (local64_cmpxchg(&hwc->period_left, old, val) != old)
9290 static void perf_swevent_overflow(struct perf_event *event, u64 overflow,
9291 struct perf_sample_data *data,
9292 struct pt_regs *regs)
9294 struct hw_perf_event *hwc = &event->hw;
9298 overflow = perf_swevent_set_period(event);
9300 if (hwc->interrupts == MAX_INTERRUPTS)
9303 for (; overflow; overflow--) {
9304 if (__perf_event_overflow(event, throttle,
9307 * We inhibit the overflow from happening when
9308 * hwc->interrupts == MAX_INTERRUPTS.
9316 static void perf_swevent_event(struct perf_event *event, u64 nr,
9317 struct perf_sample_data *data,
9318 struct pt_regs *regs)
9320 struct hw_perf_event *hwc = &event->hw;
9322 local64_add(nr, &event->count);
9327 if (!is_sampling_event(event))
9330 if ((event->attr.sample_type & PERF_SAMPLE_PERIOD) && !event->attr.freq) {
9332 return perf_swevent_overflow(event, 1, data, regs);
9334 data->period = event->hw.last_period;
9336 if (nr == 1 && hwc->sample_period == 1 && !event->attr.freq)
9337 return perf_swevent_overflow(event, 1, data, regs);
9339 if (local64_add_negative(nr, &hwc->period_left))
9342 perf_swevent_overflow(event, 0, data, regs);
9345 static int perf_exclude_event(struct perf_event *event,
9346 struct pt_regs *regs)
9348 if (event->hw.state & PERF_HES_STOPPED)
9352 if (event->attr.exclude_user && user_mode(regs))
9355 if (event->attr.exclude_kernel && !user_mode(regs))
9362 static int perf_swevent_match(struct perf_event *event,
9363 enum perf_type_id type,
9365 struct perf_sample_data *data,
9366 struct pt_regs *regs)
9368 if (event->attr.type != type)
9371 if (event->attr.config != event_id)
9374 if (perf_exclude_event(event, regs))
9380 static inline u64 swevent_hash(u64 type, u32 event_id)
9382 u64 val = event_id | (type << 32);
9384 return hash_64(val, SWEVENT_HLIST_BITS);
9387 static inline struct hlist_head *
9388 __find_swevent_head(struct swevent_hlist *hlist, u64 type, u32 event_id)
9390 u64 hash = swevent_hash(type, event_id);
9392 return &hlist->heads[hash];
9395 /* For the read side: events when they trigger */
9396 static inline struct hlist_head *
9397 find_swevent_head_rcu(struct swevent_htable *swhash, u64 type, u32 event_id)
9399 struct swevent_hlist *hlist;
9401 hlist = rcu_dereference(swhash->swevent_hlist);
9405 return __find_swevent_head(hlist, type, event_id);
9408 /* For the event head insertion and removal in the hlist */
9409 static inline struct hlist_head *
9410 find_swevent_head(struct swevent_htable *swhash, struct perf_event *event)
9412 struct swevent_hlist *hlist;
9413 u32 event_id = event->attr.config;
9414 u64 type = event->attr.type;
9417 * Event scheduling is always serialized against hlist allocation
9418 * and release. Which makes the protected version suitable here.
9419 * The context lock guarantees that.
9421 hlist = rcu_dereference_protected(swhash->swevent_hlist,
9422 lockdep_is_held(&event->ctx->lock));
9426 return __find_swevent_head(hlist, type, event_id);
9429 static void do_perf_sw_event(enum perf_type_id type, u32 event_id,
9431 struct perf_sample_data *data,
9432 struct pt_regs *regs)
9434 struct swevent_htable *swhash = this_cpu_ptr(&swevent_htable);
9435 struct perf_event *event;
9436 struct hlist_head *head;
9439 head = find_swevent_head_rcu(swhash, type, event_id);
9443 hlist_for_each_entry_rcu(event, head, hlist_entry) {
9444 if (perf_swevent_match(event, type, event_id, data, regs))
9445 perf_swevent_event(event, nr, data, regs);
9451 DEFINE_PER_CPU(struct pt_regs, __perf_regs[4]);
9453 int perf_swevent_get_recursion_context(void)
9455 struct swevent_htable *swhash = this_cpu_ptr(&swevent_htable);
9457 return get_recursion_context(swhash->recursion);
9459 EXPORT_SYMBOL_GPL(perf_swevent_get_recursion_context);
9461 void perf_swevent_put_recursion_context(int rctx)
9463 struct swevent_htable *swhash = this_cpu_ptr(&swevent_htable);
9465 put_recursion_context(swhash->recursion, rctx);
9468 void ___perf_sw_event(u32 event_id, u64 nr, struct pt_regs *regs, u64 addr)
9470 struct perf_sample_data data;
9472 if (WARN_ON_ONCE(!regs))
9475 perf_sample_data_init(&data, addr, 0);
9476 do_perf_sw_event(PERF_TYPE_SOFTWARE, event_id, nr, &data, regs);
9479 void __perf_sw_event(u32 event_id, u64 nr, struct pt_regs *regs, u64 addr)
9483 preempt_disable_notrace();
9484 rctx = perf_swevent_get_recursion_context();
9485 if (unlikely(rctx < 0))
9488 ___perf_sw_event(event_id, nr, regs, addr);
9490 perf_swevent_put_recursion_context(rctx);
9492 preempt_enable_notrace();
9495 static void perf_swevent_read(struct perf_event *event)
9499 static int perf_swevent_add(struct perf_event *event, int flags)
9501 struct swevent_htable *swhash = this_cpu_ptr(&swevent_htable);
9502 struct hw_perf_event *hwc = &event->hw;
9503 struct hlist_head *head;
9505 if (is_sampling_event(event)) {
9506 hwc->last_period = hwc->sample_period;
9507 perf_swevent_set_period(event);
9510 hwc->state = !(flags & PERF_EF_START);
9512 head = find_swevent_head(swhash, event);
9513 if (WARN_ON_ONCE(!head))
9516 hlist_add_head_rcu(&event->hlist_entry, head);
9517 perf_event_update_userpage(event);
9522 static void perf_swevent_del(struct perf_event *event, int flags)
9524 hlist_del_rcu(&event->hlist_entry);
9527 static void perf_swevent_start(struct perf_event *event, int flags)
9529 event->hw.state = 0;
9532 static void perf_swevent_stop(struct perf_event *event, int flags)
9534 event->hw.state = PERF_HES_STOPPED;
9537 /* Deref the hlist from the update side */
9538 static inline struct swevent_hlist *
9539 swevent_hlist_deref(struct swevent_htable *swhash)
9541 return rcu_dereference_protected(swhash->swevent_hlist,
9542 lockdep_is_held(&swhash->hlist_mutex));
9545 static void swevent_hlist_release(struct swevent_htable *swhash)
9547 struct swevent_hlist *hlist = swevent_hlist_deref(swhash);
9552 RCU_INIT_POINTER(swhash->swevent_hlist, NULL);
9553 kfree_rcu(hlist, rcu_head);
9556 static void swevent_hlist_put_cpu(int cpu)
9558 struct swevent_htable *swhash = &per_cpu(swevent_htable, cpu);
9560 mutex_lock(&swhash->hlist_mutex);
9562 if (!--swhash->hlist_refcount)
9563 swevent_hlist_release(swhash);
9565 mutex_unlock(&swhash->hlist_mutex);
9568 static void swevent_hlist_put(void)
9572 for_each_possible_cpu(cpu)
9573 swevent_hlist_put_cpu(cpu);
9576 static int swevent_hlist_get_cpu(int cpu)
9578 struct swevent_htable *swhash = &per_cpu(swevent_htable, cpu);
9581 mutex_lock(&swhash->hlist_mutex);
9582 if (!swevent_hlist_deref(swhash) &&
9583 cpumask_test_cpu(cpu, perf_online_mask)) {
9584 struct swevent_hlist *hlist;
9586 hlist = kzalloc(sizeof(*hlist), GFP_KERNEL);
9591 rcu_assign_pointer(swhash->swevent_hlist, hlist);
9593 swhash->hlist_refcount++;
9595 mutex_unlock(&swhash->hlist_mutex);
9600 static int swevent_hlist_get(void)
9602 int err, cpu, failed_cpu;
9604 mutex_lock(&pmus_lock);
9605 for_each_possible_cpu(cpu) {
9606 err = swevent_hlist_get_cpu(cpu);
9612 mutex_unlock(&pmus_lock);
9615 for_each_possible_cpu(cpu) {
9616 if (cpu == failed_cpu)
9618 swevent_hlist_put_cpu(cpu);
9620 mutex_unlock(&pmus_lock);
9624 struct static_key perf_swevent_enabled[PERF_COUNT_SW_MAX];
9626 static void sw_perf_event_destroy(struct perf_event *event)
9628 u64 event_id = event->attr.config;
9630 WARN_ON(event->parent);
9632 static_key_slow_dec(&perf_swevent_enabled[event_id]);
9633 swevent_hlist_put();
9636 static int perf_swevent_init(struct perf_event *event)
9638 u64 event_id = event->attr.config;
9640 if (event->attr.type != PERF_TYPE_SOFTWARE)
9644 * no branch sampling for software events
9646 if (has_branch_stack(event))
9650 case PERF_COUNT_SW_CPU_CLOCK:
9651 case PERF_COUNT_SW_TASK_CLOCK:
9658 if (event_id >= PERF_COUNT_SW_MAX)
9661 if (!event->parent) {
9664 err = swevent_hlist_get();
9668 static_key_slow_inc(&perf_swevent_enabled[event_id]);
9669 event->destroy = sw_perf_event_destroy;
9675 static struct pmu perf_swevent = {
9676 .task_ctx_nr = perf_sw_context,
9678 .capabilities = PERF_PMU_CAP_NO_NMI,
9680 .event_init = perf_swevent_init,
9681 .add = perf_swevent_add,
9682 .del = perf_swevent_del,
9683 .start = perf_swevent_start,
9684 .stop = perf_swevent_stop,
9685 .read = perf_swevent_read,
9688 #ifdef CONFIG_EVENT_TRACING
9690 static int perf_tp_filter_match(struct perf_event *event,
9691 struct perf_sample_data *data)
9693 void *record = data->raw->frag.data;
9695 /* only top level events have filters set */
9697 event = event->parent;
9699 if (likely(!event->filter) || filter_match_preds(event->filter, record))
9704 static int perf_tp_event_match(struct perf_event *event,
9705 struct perf_sample_data *data,
9706 struct pt_regs *regs)
9708 if (event->hw.state & PERF_HES_STOPPED)
9711 * If exclude_kernel, only trace user-space tracepoints (uprobes)
9713 if (event->attr.exclude_kernel && !user_mode(regs))
9716 if (!perf_tp_filter_match(event, data))
9722 void perf_trace_run_bpf_submit(void *raw_data, int size, int rctx,
9723 struct trace_event_call *call, u64 count,
9724 struct pt_regs *regs, struct hlist_head *head,
9725 struct task_struct *task)
9727 if (bpf_prog_array_valid(call)) {
9728 *(struct pt_regs **)raw_data = regs;
9729 if (!trace_call_bpf(call, raw_data) || hlist_empty(head)) {
9730 perf_swevent_put_recursion_context(rctx);
9734 perf_tp_event(call->event.type, count, raw_data, size, regs, head,
9737 EXPORT_SYMBOL_GPL(perf_trace_run_bpf_submit);
9739 void perf_tp_event(u16 event_type, u64 count, void *record, int entry_size,
9740 struct pt_regs *regs, struct hlist_head *head, int rctx,
9741 struct task_struct *task)
9743 struct perf_sample_data data;
9744 struct perf_event *event;
9746 struct perf_raw_record raw = {
9753 perf_sample_data_init(&data, 0, 0);
9756 perf_trace_buf_update(record, event_type);
9758 hlist_for_each_entry_rcu(event, head, hlist_entry) {
9759 if (perf_tp_event_match(event, &data, regs))
9760 perf_swevent_event(event, count, &data, regs);
9764 * If we got specified a target task, also iterate its context and
9765 * deliver this event there too.
9767 if (task && task != current) {
9768 struct perf_event_context *ctx;
9769 struct trace_entry *entry = record;
9772 ctx = rcu_dereference(task->perf_event_ctxp[perf_sw_context]);
9776 list_for_each_entry_rcu(event, &ctx->event_list, event_entry) {
9777 if (event->cpu != smp_processor_id())
9779 if (event->attr.type != PERF_TYPE_TRACEPOINT)
9781 if (event->attr.config != entry->type)
9783 /* Cannot deliver synchronous signal to other task. */
9784 if (event->attr.sigtrap)
9786 if (perf_tp_event_match(event, &data, regs))
9787 perf_swevent_event(event, count, &data, regs);
9793 perf_swevent_put_recursion_context(rctx);
9795 EXPORT_SYMBOL_GPL(perf_tp_event);
9797 static void tp_perf_event_destroy(struct perf_event *event)
9799 perf_trace_destroy(event);
9802 static int perf_tp_event_init(struct perf_event *event)
9806 if (event->attr.type != PERF_TYPE_TRACEPOINT)
9810 * no branch sampling for tracepoint events
9812 if (has_branch_stack(event))
9815 err = perf_trace_init(event);
9819 event->destroy = tp_perf_event_destroy;
9824 static struct pmu perf_tracepoint = {
9825 .task_ctx_nr = perf_sw_context,
9827 .event_init = perf_tp_event_init,
9828 .add = perf_trace_add,
9829 .del = perf_trace_del,
9830 .start = perf_swevent_start,
9831 .stop = perf_swevent_stop,
9832 .read = perf_swevent_read,
9835 #if defined(CONFIG_KPROBE_EVENTS) || defined(CONFIG_UPROBE_EVENTS)
9837 * Flags in config, used by dynamic PMU kprobe and uprobe
9838 * The flags should match following PMU_FORMAT_ATTR().
9840 * PERF_PROBE_CONFIG_IS_RETPROBE if set, create kretprobe/uretprobe
9841 * if not set, create kprobe/uprobe
9843 * The following values specify a reference counter (or semaphore in the
9844 * terminology of tools like dtrace, systemtap, etc.) Userspace Statically
9845 * Defined Tracepoints (USDT). Currently, we use 40 bit for the offset.
9847 * PERF_UPROBE_REF_CTR_OFFSET_BITS # of bits in config as th offset
9848 * PERF_UPROBE_REF_CTR_OFFSET_SHIFT # of bits to shift left
9850 enum perf_probe_config {
9851 PERF_PROBE_CONFIG_IS_RETPROBE = 1U << 0, /* [k,u]retprobe */
9852 PERF_UPROBE_REF_CTR_OFFSET_BITS = 32,
9853 PERF_UPROBE_REF_CTR_OFFSET_SHIFT = 64 - PERF_UPROBE_REF_CTR_OFFSET_BITS,
9856 PMU_FORMAT_ATTR(retprobe, "config:0");
9859 #ifdef CONFIG_KPROBE_EVENTS
9860 static struct attribute *kprobe_attrs[] = {
9861 &format_attr_retprobe.attr,
9865 static struct attribute_group kprobe_format_group = {
9867 .attrs = kprobe_attrs,
9870 static const struct attribute_group *kprobe_attr_groups[] = {
9871 &kprobe_format_group,
9875 static int perf_kprobe_event_init(struct perf_event *event);
9876 static struct pmu perf_kprobe = {
9877 .task_ctx_nr = perf_sw_context,
9878 .event_init = perf_kprobe_event_init,
9879 .add = perf_trace_add,
9880 .del = perf_trace_del,
9881 .start = perf_swevent_start,
9882 .stop = perf_swevent_stop,
9883 .read = perf_swevent_read,
9884 .attr_groups = kprobe_attr_groups,
9887 static int perf_kprobe_event_init(struct perf_event *event)
9892 if (event->attr.type != perf_kprobe.type)
9895 if (!perfmon_capable())
9899 * no branch sampling for probe events
9901 if (has_branch_stack(event))
9904 is_retprobe = event->attr.config & PERF_PROBE_CONFIG_IS_RETPROBE;
9905 err = perf_kprobe_init(event, is_retprobe);
9909 event->destroy = perf_kprobe_destroy;
9913 #endif /* CONFIG_KPROBE_EVENTS */
9915 #ifdef CONFIG_UPROBE_EVENTS
9916 PMU_FORMAT_ATTR(ref_ctr_offset, "config:32-63");
9918 static struct attribute *uprobe_attrs[] = {
9919 &format_attr_retprobe.attr,
9920 &format_attr_ref_ctr_offset.attr,
9924 static struct attribute_group uprobe_format_group = {
9926 .attrs = uprobe_attrs,
9929 static const struct attribute_group *uprobe_attr_groups[] = {
9930 &uprobe_format_group,
9934 static int perf_uprobe_event_init(struct perf_event *event);
9935 static struct pmu perf_uprobe = {
9936 .task_ctx_nr = perf_sw_context,
9937 .event_init = perf_uprobe_event_init,
9938 .add = perf_trace_add,
9939 .del = perf_trace_del,
9940 .start = perf_swevent_start,
9941 .stop = perf_swevent_stop,
9942 .read = perf_swevent_read,
9943 .attr_groups = uprobe_attr_groups,
9946 static int perf_uprobe_event_init(struct perf_event *event)
9949 unsigned long ref_ctr_offset;
9952 if (event->attr.type != perf_uprobe.type)
9955 if (!perfmon_capable())
9959 * no branch sampling for probe events
9961 if (has_branch_stack(event))
9964 is_retprobe = event->attr.config & PERF_PROBE_CONFIG_IS_RETPROBE;
9965 ref_ctr_offset = event->attr.config >> PERF_UPROBE_REF_CTR_OFFSET_SHIFT;
9966 err = perf_uprobe_init(event, ref_ctr_offset, is_retprobe);
9970 event->destroy = perf_uprobe_destroy;
9974 #endif /* CONFIG_UPROBE_EVENTS */
9976 static inline void perf_tp_register(void)
9978 perf_pmu_register(&perf_tracepoint, "tracepoint", PERF_TYPE_TRACEPOINT);
9979 #ifdef CONFIG_KPROBE_EVENTS
9980 perf_pmu_register(&perf_kprobe, "kprobe", -1);
9982 #ifdef CONFIG_UPROBE_EVENTS
9983 perf_pmu_register(&perf_uprobe, "uprobe", -1);
9987 static void perf_event_free_filter(struct perf_event *event)
9989 ftrace_profile_free_filter(event);
9992 #ifdef CONFIG_BPF_SYSCALL
9993 static void bpf_overflow_handler(struct perf_event *event,
9994 struct perf_sample_data *data,
9995 struct pt_regs *regs)
9997 struct bpf_perf_event_data_kern ctx = {
10001 struct bpf_prog *prog;
10004 ctx.regs = perf_arch_bpf_user_pt_regs(regs);
10005 if (unlikely(__this_cpu_inc_return(bpf_prog_active) != 1))
10008 prog = READ_ONCE(event->prog);
10010 ret = bpf_prog_run(prog, &ctx);
10013 __this_cpu_dec(bpf_prog_active);
10017 event->orig_overflow_handler(event, data, regs);
10020 static int perf_event_set_bpf_handler(struct perf_event *event,
10021 struct bpf_prog *prog,
10024 if (event->overflow_handler_context)
10025 /* hw breakpoint or kernel counter */
10031 if (prog->type != BPF_PROG_TYPE_PERF_EVENT)
10034 if (event->attr.precise_ip &&
10035 prog->call_get_stack &&
10036 (!(event->attr.sample_type & __PERF_SAMPLE_CALLCHAIN_EARLY) ||
10037 event->attr.exclude_callchain_kernel ||
10038 event->attr.exclude_callchain_user)) {
10040 * On perf_event with precise_ip, calling bpf_get_stack()
10041 * may trigger unwinder warnings and occasional crashes.
10042 * bpf_get_[stack|stackid] works around this issue by using
10043 * callchain attached to perf_sample_data. If the
10044 * perf_event does not full (kernel and user) callchain
10045 * attached to perf_sample_data, do not allow attaching BPF
10046 * program that calls bpf_get_[stack|stackid].
10051 event->prog = prog;
10052 event->bpf_cookie = bpf_cookie;
10053 event->orig_overflow_handler = READ_ONCE(event->overflow_handler);
10054 WRITE_ONCE(event->overflow_handler, bpf_overflow_handler);
10058 static void perf_event_free_bpf_handler(struct perf_event *event)
10060 struct bpf_prog *prog = event->prog;
10065 WRITE_ONCE(event->overflow_handler, event->orig_overflow_handler);
10066 event->prog = NULL;
10067 bpf_prog_put(prog);
10070 static int perf_event_set_bpf_handler(struct perf_event *event,
10071 struct bpf_prog *prog,
10074 return -EOPNOTSUPP;
10076 static void perf_event_free_bpf_handler(struct perf_event *event)
10082 * returns true if the event is a tracepoint, or a kprobe/upprobe created
10083 * with perf_event_open()
10085 static inline bool perf_event_is_tracing(struct perf_event *event)
10087 if (event->pmu == &perf_tracepoint)
10089 #ifdef CONFIG_KPROBE_EVENTS
10090 if (event->pmu == &perf_kprobe)
10093 #ifdef CONFIG_UPROBE_EVENTS
10094 if (event->pmu == &perf_uprobe)
10100 int perf_event_set_bpf_prog(struct perf_event *event, struct bpf_prog *prog,
10103 bool is_kprobe, is_tracepoint, is_syscall_tp;
10105 if (!perf_event_is_tracing(event))
10106 return perf_event_set_bpf_handler(event, prog, bpf_cookie);
10108 is_kprobe = event->tp_event->flags & TRACE_EVENT_FL_UKPROBE;
10109 is_tracepoint = event->tp_event->flags & TRACE_EVENT_FL_TRACEPOINT;
10110 is_syscall_tp = is_syscall_trace_event(event->tp_event);
10111 if (!is_kprobe && !is_tracepoint && !is_syscall_tp)
10112 /* bpf programs can only be attached to u/kprobe or tracepoint */
10115 if ((is_kprobe && prog->type != BPF_PROG_TYPE_KPROBE) ||
10116 (is_tracepoint && prog->type != BPF_PROG_TYPE_TRACEPOINT) ||
10117 (is_syscall_tp && prog->type != BPF_PROG_TYPE_TRACEPOINT))
10120 /* Kprobe override only works for kprobes, not uprobes. */
10121 if (prog->kprobe_override &&
10122 !(event->tp_event->flags & TRACE_EVENT_FL_KPROBE))
10125 if (is_tracepoint || is_syscall_tp) {
10126 int off = trace_event_get_offsets(event->tp_event);
10128 if (prog->aux->max_ctx_offset > off)
10132 return perf_event_attach_bpf_prog(event, prog, bpf_cookie);
10135 void perf_event_free_bpf_prog(struct perf_event *event)
10137 if (!perf_event_is_tracing(event)) {
10138 perf_event_free_bpf_handler(event);
10141 perf_event_detach_bpf_prog(event);
10146 static inline void perf_tp_register(void)
10150 static void perf_event_free_filter(struct perf_event *event)
10154 int perf_event_set_bpf_prog(struct perf_event *event, struct bpf_prog *prog,
10160 void perf_event_free_bpf_prog(struct perf_event *event)
10163 #endif /* CONFIG_EVENT_TRACING */
10165 #ifdef CONFIG_HAVE_HW_BREAKPOINT
10166 void perf_bp_event(struct perf_event *bp, void *data)
10168 struct perf_sample_data sample;
10169 struct pt_regs *regs = data;
10171 perf_sample_data_init(&sample, bp->attr.bp_addr, 0);
10173 if (!bp->hw.state && !perf_exclude_event(bp, regs))
10174 perf_swevent_event(bp, 1, &sample, regs);
10179 * Allocate a new address filter
10181 static struct perf_addr_filter *
10182 perf_addr_filter_new(struct perf_event *event, struct list_head *filters)
10184 int node = cpu_to_node(event->cpu == -1 ? 0 : event->cpu);
10185 struct perf_addr_filter *filter;
10187 filter = kzalloc_node(sizeof(*filter), GFP_KERNEL, node);
10191 INIT_LIST_HEAD(&filter->entry);
10192 list_add_tail(&filter->entry, filters);
10197 static void free_filters_list(struct list_head *filters)
10199 struct perf_addr_filter *filter, *iter;
10201 list_for_each_entry_safe(filter, iter, filters, entry) {
10202 path_put(&filter->path);
10203 list_del(&filter->entry);
10209 * Free existing address filters and optionally install new ones
10211 static void perf_addr_filters_splice(struct perf_event *event,
10212 struct list_head *head)
10214 unsigned long flags;
10217 if (!has_addr_filter(event))
10220 /* don't bother with children, they don't have their own filters */
10224 raw_spin_lock_irqsave(&event->addr_filters.lock, flags);
10226 list_splice_init(&event->addr_filters.list, &list);
10228 list_splice(head, &event->addr_filters.list);
10230 raw_spin_unlock_irqrestore(&event->addr_filters.lock, flags);
10232 free_filters_list(&list);
10236 * Scan through mm's vmas and see if one of them matches the
10237 * @filter; if so, adjust filter's address range.
10238 * Called with mm::mmap_lock down for reading.
10240 static void perf_addr_filter_apply(struct perf_addr_filter *filter,
10241 struct mm_struct *mm,
10242 struct perf_addr_filter_range *fr)
10244 struct vm_area_struct *vma;
10246 for (vma = mm->mmap; vma; vma = vma->vm_next) {
10250 if (perf_addr_filter_vma_adjust(filter, vma, fr))
10256 * Update event's address range filters based on the
10257 * task's existing mappings, if any.
10259 static void perf_event_addr_filters_apply(struct perf_event *event)
10261 struct perf_addr_filters_head *ifh = perf_event_addr_filters(event);
10262 struct task_struct *task = READ_ONCE(event->ctx->task);
10263 struct perf_addr_filter *filter;
10264 struct mm_struct *mm = NULL;
10265 unsigned int count = 0;
10266 unsigned long flags;
10269 * We may observe TASK_TOMBSTONE, which means that the event tear-down
10270 * will stop on the parent's child_mutex that our caller is also holding
10272 if (task == TASK_TOMBSTONE)
10275 if (ifh->nr_file_filters) {
10276 mm = get_task_mm(task);
10280 mmap_read_lock(mm);
10283 raw_spin_lock_irqsave(&ifh->lock, flags);
10284 list_for_each_entry(filter, &ifh->list, entry) {
10285 if (filter->path.dentry) {
10287 * Adjust base offset if the filter is associated to a
10288 * binary that needs to be mapped:
10290 event->addr_filter_ranges[count].start = 0;
10291 event->addr_filter_ranges[count].size = 0;
10293 perf_addr_filter_apply(filter, mm, &event->addr_filter_ranges[count]);
10295 event->addr_filter_ranges[count].start = filter->offset;
10296 event->addr_filter_ranges[count].size = filter->size;
10302 event->addr_filters_gen++;
10303 raw_spin_unlock_irqrestore(&ifh->lock, flags);
10305 if (ifh->nr_file_filters) {
10306 mmap_read_unlock(mm);
10312 perf_event_stop(event, 1);
10316 * Address range filtering: limiting the data to certain
10317 * instruction address ranges. Filters are ioctl()ed to us from
10318 * userspace as ascii strings.
10320 * Filter string format:
10322 * ACTION RANGE_SPEC
10323 * where ACTION is one of the
10324 * * "filter": limit the trace to this region
10325 * * "start": start tracing from this address
10326 * * "stop": stop tracing at this address/region;
10328 * * for kernel addresses: <start address>[/<size>]
10329 * * for object files: <start address>[/<size>]@</path/to/object/file>
10331 * if <size> is not specified or is zero, the range is treated as a single
10332 * address; not valid for ACTION=="filter".
10346 IF_STATE_ACTION = 0,
10351 static const match_table_t if_tokens = {
10352 { IF_ACT_FILTER, "filter" },
10353 { IF_ACT_START, "start" },
10354 { IF_ACT_STOP, "stop" },
10355 { IF_SRC_FILE, "%u/%u@%s" },
10356 { IF_SRC_KERNEL, "%u/%u" },
10357 { IF_SRC_FILEADDR, "%u@%s" },
10358 { IF_SRC_KERNELADDR, "%u" },
10359 { IF_ACT_NONE, NULL },
10363 * Address filter string parser
10366 perf_event_parse_addr_filter(struct perf_event *event, char *fstr,
10367 struct list_head *filters)
10369 struct perf_addr_filter *filter = NULL;
10370 char *start, *orig, *filename = NULL;
10371 substring_t args[MAX_OPT_ARGS];
10372 int state = IF_STATE_ACTION, token;
10373 unsigned int kernel = 0;
10376 orig = fstr = kstrdup(fstr, GFP_KERNEL);
10380 while ((start = strsep(&fstr, " ,\n")) != NULL) {
10381 static const enum perf_addr_filter_action_t actions[] = {
10382 [IF_ACT_FILTER] = PERF_ADDR_FILTER_ACTION_FILTER,
10383 [IF_ACT_START] = PERF_ADDR_FILTER_ACTION_START,
10384 [IF_ACT_STOP] = PERF_ADDR_FILTER_ACTION_STOP,
10391 /* filter definition begins */
10392 if (state == IF_STATE_ACTION) {
10393 filter = perf_addr_filter_new(event, filters);
10398 token = match_token(start, if_tokens, args);
10400 case IF_ACT_FILTER:
10403 if (state != IF_STATE_ACTION)
10406 filter->action = actions[token];
10407 state = IF_STATE_SOURCE;
10410 case IF_SRC_KERNELADDR:
10411 case IF_SRC_KERNEL:
10415 case IF_SRC_FILEADDR:
10417 if (state != IF_STATE_SOURCE)
10421 ret = kstrtoul(args[0].from, 0, &filter->offset);
10425 if (token == IF_SRC_KERNEL || token == IF_SRC_FILE) {
10427 ret = kstrtoul(args[1].from, 0, &filter->size);
10432 if (token == IF_SRC_FILE || token == IF_SRC_FILEADDR) {
10433 int fpos = token == IF_SRC_FILE ? 2 : 1;
10436 filename = match_strdup(&args[fpos]);
10443 state = IF_STATE_END;
10451 * Filter definition is fully parsed, validate and install it.
10452 * Make sure that it doesn't contradict itself or the event's
10455 if (state == IF_STATE_END) {
10457 if (kernel && event->attr.exclude_kernel)
10461 * ACTION "filter" must have a non-zero length region
10464 if (filter->action == PERF_ADDR_FILTER_ACTION_FILTER &&
10473 * For now, we only support file-based filters
10474 * in per-task events; doing so for CPU-wide
10475 * events requires additional context switching
10476 * trickery, since same object code will be
10477 * mapped at different virtual addresses in
10478 * different processes.
10481 if (!event->ctx->task)
10484 /* look up the path and grab its inode */
10485 ret = kern_path(filename, LOOKUP_FOLLOW,
10491 if (!filter->path.dentry ||
10492 !S_ISREG(d_inode(filter->path.dentry)
10496 event->addr_filters.nr_file_filters++;
10499 /* ready to consume more filters */
10500 state = IF_STATE_ACTION;
10505 if (state != IF_STATE_ACTION)
10515 free_filters_list(filters);
10522 perf_event_set_addr_filter(struct perf_event *event, char *filter_str)
10524 LIST_HEAD(filters);
10528 * Since this is called in perf_ioctl() path, we're already holding
10531 lockdep_assert_held(&event->ctx->mutex);
10533 if (WARN_ON_ONCE(event->parent))
10536 ret = perf_event_parse_addr_filter(event, filter_str, &filters);
10538 goto fail_clear_files;
10540 ret = event->pmu->addr_filters_validate(&filters);
10542 goto fail_free_filters;
10544 /* remove existing filters, if any */
10545 perf_addr_filters_splice(event, &filters);
10547 /* install new filters */
10548 perf_event_for_each_child(event, perf_event_addr_filters_apply);
10553 free_filters_list(&filters);
10556 event->addr_filters.nr_file_filters = 0;
10561 static int perf_event_set_filter(struct perf_event *event, void __user *arg)
10566 filter_str = strndup_user(arg, PAGE_SIZE);
10567 if (IS_ERR(filter_str))
10568 return PTR_ERR(filter_str);
10570 #ifdef CONFIG_EVENT_TRACING
10571 if (perf_event_is_tracing(event)) {
10572 struct perf_event_context *ctx = event->ctx;
10575 * Beware, here be dragons!!
10577 * the tracepoint muck will deadlock against ctx->mutex, but
10578 * the tracepoint stuff does not actually need it. So
10579 * temporarily drop ctx->mutex. As per perf_event_ctx_lock() we
10580 * already have a reference on ctx.
10582 * This can result in event getting moved to a different ctx,
10583 * but that does not affect the tracepoint state.
10585 mutex_unlock(&ctx->mutex);
10586 ret = ftrace_profile_set_filter(event, event->attr.config, filter_str);
10587 mutex_lock(&ctx->mutex);
10590 if (has_addr_filter(event))
10591 ret = perf_event_set_addr_filter(event, filter_str);
10598 * hrtimer based swevent callback
10601 static enum hrtimer_restart perf_swevent_hrtimer(struct hrtimer *hrtimer)
10603 enum hrtimer_restart ret = HRTIMER_RESTART;
10604 struct perf_sample_data data;
10605 struct pt_regs *regs;
10606 struct perf_event *event;
10609 event = container_of(hrtimer, struct perf_event, hw.hrtimer);
10611 if (event->state != PERF_EVENT_STATE_ACTIVE)
10612 return HRTIMER_NORESTART;
10614 event->pmu->read(event);
10616 perf_sample_data_init(&data, 0, event->hw.last_period);
10617 regs = get_irq_regs();
10619 if (regs && !perf_exclude_event(event, regs)) {
10620 if (!(event->attr.exclude_idle && is_idle_task(current)))
10621 if (__perf_event_overflow(event, 1, &data, regs))
10622 ret = HRTIMER_NORESTART;
10625 period = max_t(u64, 10000, event->hw.sample_period);
10626 hrtimer_forward_now(hrtimer, ns_to_ktime(period));
10631 static void perf_swevent_start_hrtimer(struct perf_event *event)
10633 struct hw_perf_event *hwc = &event->hw;
10636 if (!is_sampling_event(event))
10639 period = local64_read(&hwc->period_left);
10644 local64_set(&hwc->period_left, 0);
10646 period = max_t(u64, 10000, hwc->sample_period);
10648 hrtimer_start(&hwc->hrtimer, ns_to_ktime(period),
10649 HRTIMER_MODE_REL_PINNED_HARD);
10652 static void perf_swevent_cancel_hrtimer(struct perf_event *event)
10654 struct hw_perf_event *hwc = &event->hw;
10656 if (is_sampling_event(event)) {
10657 ktime_t remaining = hrtimer_get_remaining(&hwc->hrtimer);
10658 local64_set(&hwc->period_left, ktime_to_ns(remaining));
10660 hrtimer_cancel(&hwc->hrtimer);
10664 static void perf_swevent_init_hrtimer(struct perf_event *event)
10666 struct hw_perf_event *hwc = &event->hw;
10668 if (!is_sampling_event(event))
10671 hrtimer_init(&hwc->hrtimer, CLOCK_MONOTONIC, HRTIMER_MODE_REL_HARD);
10672 hwc->hrtimer.function = perf_swevent_hrtimer;
10675 * Since hrtimers have a fixed rate, we can do a static freq->period
10676 * mapping and avoid the whole period adjust feedback stuff.
10678 if (event->attr.freq) {
10679 long freq = event->attr.sample_freq;
10681 event->attr.sample_period = NSEC_PER_SEC / freq;
10682 hwc->sample_period = event->attr.sample_period;
10683 local64_set(&hwc->period_left, hwc->sample_period);
10684 hwc->last_period = hwc->sample_period;
10685 event->attr.freq = 0;
10690 * Software event: cpu wall time clock
10693 static void cpu_clock_event_update(struct perf_event *event)
10698 now = local_clock();
10699 prev = local64_xchg(&event->hw.prev_count, now);
10700 local64_add(now - prev, &event->count);
10703 static void cpu_clock_event_start(struct perf_event *event, int flags)
10705 local64_set(&event->hw.prev_count, local_clock());
10706 perf_swevent_start_hrtimer(event);
10709 static void cpu_clock_event_stop(struct perf_event *event, int flags)
10711 perf_swevent_cancel_hrtimer(event);
10712 cpu_clock_event_update(event);
10715 static int cpu_clock_event_add(struct perf_event *event, int flags)
10717 if (flags & PERF_EF_START)
10718 cpu_clock_event_start(event, flags);
10719 perf_event_update_userpage(event);
10724 static void cpu_clock_event_del(struct perf_event *event, int flags)
10726 cpu_clock_event_stop(event, flags);
10729 static void cpu_clock_event_read(struct perf_event *event)
10731 cpu_clock_event_update(event);
10734 static int cpu_clock_event_init(struct perf_event *event)
10736 if (event->attr.type != PERF_TYPE_SOFTWARE)
10739 if (event->attr.config != PERF_COUNT_SW_CPU_CLOCK)
10743 * no branch sampling for software events
10745 if (has_branch_stack(event))
10746 return -EOPNOTSUPP;
10748 perf_swevent_init_hrtimer(event);
10753 static struct pmu perf_cpu_clock = {
10754 .task_ctx_nr = perf_sw_context,
10756 .capabilities = PERF_PMU_CAP_NO_NMI,
10758 .event_init = cpu_clock_event_init,
10759 .add = cpu_clock_event_add,
10760 .del = cpu_clock_event_del,
10761 .start = cpu_clock_event_start,
10762 .stop = cpu_clock_event_stop,
10763 .read = cpu_clock_event_read,
10767 * Software event: task time clock
10770 static void task_clock_event_update(struct perf_event *event, u64 now)
10775 prev = local64_xchg(&event->hw.prev_count, now);
10776 delta = now - prev;
10777 local64_add(delta, &event->count);
10780 static void task_clock_event_start(struct perf_event *event, int flags)
10782 local64_set(&event->hw.prev_count, event->ctx->time);
10783 perf_swevent_start_hrtimer(event);
10786 static void task_clock_event_stop(struct perf_event *event, int flags)
10788 perf_swevent_cancel_hrtimer(event);
10789 task_clock_event_update(event, event->ctx->time);
10792 static int task_clock_event_add(struct perf_event *event, int flags)
10794 if (flags & PERF_EF_START)
10795 task_clock_event_start(event, flags);
10796 perf_event_update_userpage(event);
10801 static void task_clock_event_del(struct perf_event *event, int flags)
10803 task_clock_event_stop(event, PERF_EF_UPDATE);
10806 static void task_clock_event_read(struct perf_event *event)
10808 u64 now = perf_clock();
10809 u64 delta = now - event->ctx->timestamp;
10810 u64 time = event->ctx->time + delta;
10812 task_clock_event_update(event, time);
10815 static int task_clock_event_init(struct perf_event *event)
10817 if (event->attr.type != PERF_TYPE_SOFTWARE)
10820 if (event->attr.config != PERF_COUNT_SW_TASK_CLOCK)
10824 * no branch sampling for software events
10826 if (has_branch_stack(event))
10827 return -EOPNOTSUPP;
10829 perf_swevent_init_hrtimer(event);
10834 static struct pmu perf_task_clock = {
10835 .task_ctx_nr = perf_sw_context,
10837 .capabilities = PERF_PMU_CAP_NO_NMI,
10839 .event_init = task_clock_event_init,
10840 .add = task_clock_event_add,
10841 .del = task_clock_event_del,
10842 .start = task_clock_event_start,
10843 .stop = task_clock_event_stop,
10844 .read = task_clock_event_read,
10847 static void perf_pmu_nop_void(struct pmu *pmu)
10851 static void perf_pmu_nop_txn(struct pmu *pmu, unsigned int flags)
10855 static int perf_pmu_nop_int(struct pmu *pmu)
10860 static int perf_event_nop_int(struct perf_event *event, u64 value)
10865 static DEFINE_PER_CPU(unsigned int, nop_txn_flags);
10867 static void perf_pmu_start_txn(struct pmu *pmu, unsigned int flags)
10869 __this_cpu_write(nop_txn_flags, flags);
10871 if (flags & ~PERF_PMU_TXN_ADD)
10874 perf_pmu_disable(pmu);
10877 static int perf_pmu_commit_txn(struct pmu *pmu)
10879 unsigned int flags = __this_cpu_read(nop_txn_flags);
10881 __this_cpu_write(nop_txn_flags, 0);
10883 if (flags & ~PERF_PMU_TXN_ADD)
10886 perf_pmu_enable(pmu);
10890 static void perf_pmu_cancel_txn(struct pmu *pmu)
10892 unsigned int flags = __this_cpu_read(nop_txn_flags);
10894 __this_cpu_write(nop_txn_flags, 0);
10896 if (flags & ~PERF_PMU_TXN_ADD)
10899 perf_pmu_enable(pmu);
10902 static int perf_event_idx_default(struct perf_event *event)
10908 * Ensures all contexts with the same task_ctx_nr have the same
10909 * pmu_cpu_context too.
10911 static struct perf_cpu_context __percpu *find_pmu_context(int ctxn)
10918 list_for_each_entry(pmu, &pmus, entry) {
10919 if (pmu->task_ctx_nr == ctxn)
10920 return pmu->pmu_cpu_context;
10926 static void free_pmu_context(struct pmu *pmu)
10929 * Static contexts such as perf_sw_context have a global lifetime
10930 * and may be shared between different PMUs. Avoid freeing them
10931 * when a single PMU is going away.
10933 if (pmu->task_ctx_nr > perf_invalid_context)
10936 free_percpu(pmu->pmu_cpu_context);
10940 * Let userspace know that this PMU supports address range filtering:
10942 static ssize_t nr_addr_filters_show(struct device *dev,
10943 struct device_attribute *attr,
10946 struct pmu *pmu = dev_get_drvdata(dev);
10948 return snprintf(page, PAGE_SIZE - 1, "%d\n", pmu->nr_addr_filters);
10950 DEVICE_ATTR_RO(nr_addr_filters);
10952 static struct idr pmu_idr;
10955 type_show(struct device *dev, struct device_attribute *attr, char *page)
10957 struct pmu *pmu = dev_get_drvdata(dev);
10959 return snprintf(page, PAGE_SIZE-1, "%d\n", pmu->type);
10961 static DEVICE_ATTR_RO(type);
10964 perf_event_mux_interval_ms_show(struct device *dev,
10965 struct device_attribute *attr,
10968 struct pmu *pmu = dev_get_drvdata(dev);
10970 return snprintf(page, PAGE_SIZE-1, "%d\n", pmu->hrtimer_interval_ms);
10973 static DEFINE_MUTEX(mux_interval_mutex);
10976 perf_event_mux_interval_ms_store(struct device *dev,
10977 struct device_attribute *attr,
10978 const char *buf, size_t count)
10980 struct pmu *pmu = dev_get_drvdata(dev);
10981 int timer, cpu, ret;
10983 ret = kstrtoint(buf, 0, &timer);
10990 /* same value, noting to do */
10991 if (timer == pmu->hrtimer_interval_ms)
10994 mutex_lock(&mux_interval_mutex);
10995 pmu->hrtimer_interval_ms = timer;
10997 /* update all cpuctx for this PMU */
10999 for_each_online_cpu(cpu) {
11000 struct perf_cpu_context *cpuctx;
11001 cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
11002 cpuctx->hrtimer_interval = ns_to_ktime(NSEC_PER_MSEC * timer);
11004 cpu_function_call(cpu,
11005 (remote_function_f)perf_mux_hrtimer_restart, cpuctx);
11007 cpus_read_unlock();
11008 mutex_unlock(&mux_interval_mutex);
11012 static DEVICE_ATTR_RW(perf_event_mux_interval_ms);
11014 static struct attribute *pmu_dev_attrs[] = {
11015 &dev_attr_type.attr,
11016 &dev_attr_perf_event_mux_interval_ms.attr,
11019 ATTRIBUTE_GROUPS(pmu_dev);
11021 static int pmu_bus_running;
11022 static struct bus_type pmu_bus = {
11023 .name = "event_source",
11024 .dev_groups = pmu_dev_groups,
11027 static void pmu_dev_release(struct device *dev)
11032 static int pmu_dev_alloc(struct pmu *pmu)
11036 pmu->dev = kzalloc(sizeof(struct device), GFP_KERNEL);
11040 pmu->dev->groups = pmu->attr_groups;
11041 device_initialize(pmu->dev);
11042 ret = dev_set_name(pmu->dev, "%s", pmu->name);
11046 dev_set_drvdata(pmu->dev, pmu);
11047 pmu->dev->bus = &pmu_bus;
11048 pmu->dev->release = pmu_dev_release;
11049 ret = device_add(pmu->dev);
11053 /* For PMUs with address filters, throw in an extra attribute: */
11054 if (pmu->nr_addr_filters)
11055 ret = device_create_file(pmu->dev, &dev_attr_nr_addr_filters);
11060 if (pmu->attr_update)
11061 ret = sysfs_update_groups(&pmu->dev->kobj, pmu->attr_update);
11070 device_del(pmu->dev);
11073 put_device(pmu->dev);
11077 static struct lock_class_key cpuctx_mutex;
11078 static struct lock_class_key cpuctx_lock;
11080 int perf_pmu_register(struct pmu *pmu, const char *name, int type)
11082 int cpu, ret, max = PERF_TYPE_MAX;
11084 mutex_lock(&pmus_lock);
11086 pmu->pmu_disable_count = alloc_percpu(int);
11087 if (!pmu->pmu_disable_count)
11095 if (type != PERF_TYPE_SOFTWARE) {
11099 ret = idr_alloc(&pmu_idr, pmu, max, 0, GFP_KERNEL);
11103 WARN_ON(type >= 0 && ret != type);
11109 if (pmu_bus_running) {
11110 ret = pmu_dev_alloc(pmu);
11116 if (pmu->task_ctx_nr == perf_hw_context) {
11117 static int hw_context_taken = 0;
11120 * Other than systems with heterogeneous CPUs, it never makes
11121 * sense for two PMUs to share perf_hw_context. PMUs which are
11122 * uncore must use perf_invalid_context.
11124 if (WARN_ON_ONCE(hw_context_taken &&
11125 !(pmu->capabilities & PERF_PMU_CAP_HETEROGENEOUS_CPUS)))
11126 pmu->task_ctx_nr = perf_invalid_context;
11128 hw_context_taken = 1;
11131 pmu->pmu_cpu_context = find_pmu_context(pmu->task_ctx_nr);
11132 if (pmu->pmu_cpu_context)
11133 goto got_cpu_context;
11136 pmu->pmu_cpu_context = alloc_percpu(struct perf_cpu_context);
11137 if (!pmu->pmu_cpu_context)
11140 for_each_possible_cpu(cpu) {
11141 struct perf_cpu_context *cpuctx;
11143 cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
11144 __perf_event_init_context(&cpuctx->ctx);
11145 lockdep_set_class(&cpuctx->ctx.mutex, &cpuctx_mutex);
11146 lockdep_set_class(&cpuctx->ctx.lock, &cpuctx_lock);
11147 cpuctx->ctx.pmu = pmu;
11148 cpuctx->online = cpumask_test_cpu(cpu, perf_online_mask);
11150 __perf_mux_hrtimer_init(cpuctx, cpu);
11152 cpuctx->heap_size = ARRAY_SIZE(cpuctx->heap_default);
11153 cpuctx->heap = cpuctx->heap_default;
11157 if (!pmu->start_txn) {
11158 if (pmu->pmu_enable) {
11160 * If we have pmu_enable/pmu_disable calls, install
11161 * transaction stubs that use that to try and batch
11162 * hardware accesses.
11164 pmu->start_txn = perf_pmu_start_txn;
11165 pmu->commit_txn = perf_pmu_commit_txn;
11166 pmu->cancel_txn = perf_pmu_cancel_txn;
11168 pmu->start_txn = perf_pmu_nop_txn;
11169 pmu->commit_txn = perf_pmu_nop_int;
11170 pmu->cancel_txn = perf_pmu_nop_void;
11174 if (!pmu->pmu_enable) {
11175 pmu->pmu_enable = perf_pmu_nop_void;
11176 pmu->pmu_disable = perf_pmu_nop_void;
11179 if (!pmu->check_period)
11180 pmu->check_period = perf_event_nop_int;
11182 if (!pmu->event_idx)
11183 pmu->event_idx = perf_event_idx_default;
11186 * Ensure the TYPE_SOFTWARE PMUs are at the head of the list,
11187 * since these cannot be in the IDR. This way the linear search
11188 * is fast, provided a valid software event is provided.
11190 if (type == PERF_TYPE_SOFTWARE || !name)
11191 list_add_rcu(&pmu->entry, &pmus);
11193 list_add_tail_rcu(&pmu->entry, &pmus);
11195 atomic_set(&pmu->exclusive_cnt, 0);
11198 mutex_unlock(&pmus_lock);
11203 device_del(pmu->dev);
11204 put_device(pmu->dev);
11207 if (pmu->type != PERF_TYPE_SOFTWARE)
11208 idr_remove(&pmu_idr, pmu->type);
11211 free_percpu(pmu->pmu_disable_count);
11214 EXPORT_SYMBOL_GPL(perf_pmu_register);
11216 void perf_pmu_unregister(struct pmu *pmu)
11218 mutex_lock(&pmus_lock);
11219 list_del_rcu(&pmu->entry);
11222 * We dereference the pmu list under both SRCU and regular RCU, so
11223 * synchronize against both of those.
11225 synchronize_srcu(&pmus_srcu);
11228 free_percpu(pmu->pmu_disable_count);
11229 if (pmu->type != PERF_TYPE_SOFTWARE)
11230 idr_remove(&pmu_idr, pmu->type);
11231 if (pmu_bus_running) {
11232 if (pmu->nr_addr_filters)
11233 device_remove_file(pmu->dev, &dev_attr_nr_addr_filters);
11234 device_del(pmu->dev);
11235 put_device(pmu->dev);
11237 free_pmu_context(pmu);
11238 mutex_unlock(&pmus_lock);
11240 EXPORT_SYMBOL_GPL(perf_pmu_unregister);
11242 static inline bool has_extended_regs(struct perf_event *event)
11244 return (event->attr.sample_regs_user & PERF_REG_EXTENDED_MASK) ||
11245 (event->attr.sample_regs_intr & PERF_REG_EXTENDED_MASK);
11248 static int perf_try_init_event(struct pmu *pmu, struct perf_event *event)
11250 struct perf_event_context *ctx = NULL;
11253 if (!try_module_get(pmu->module))
11257 * A number of pmu->event_init() methods iterate the sibling_list to,
11258 * for example, validate if the group fits on the PMU. Therefore,
11259 * if this is a sibling event, acquire the ctx->mutex to protect
11260 * the sibling_list.
11262 if (event->group_leader != event && pmu->task_ctx_nr != perf_sw_context) {
11264 * This ctx->mutex can nest when we're called through
11265 * inheritance. See the perf_event_ctx_lock_nested() comment.
11267 ctx = perf_event_ctx_lock_nested(event->group_leader,
11268 SINGLE_DEPTH_NESTING);
11273 ret = pmu->event_init(event);
11276 perf_event_ctx_unlock(event->group_leader, ctx);
11279 if (!(pmu->capabilities & PERF_PMU_CAP_EXTENDED_REGS) &&
11280 has_extended_regs(event))
11283 if (pmu->capabilities & PERF_PMU_CAP_NO_EXCLUDE &&
11284 event_has_any_exclude_flag(event))
11287 if (ret && event->destroy)
11288 event->destroy(event);
11292 module_put(pmu->module);
11297 static struct pmu *perf_init_event(struct perf_event *event)
11299 bool extended_type = false;
11300 int idx, type, ret;
11303 idx = srcu_read_lock(&pmus_srcu);
11305 /* Try parent's PMU first: */
11306 if (event->parent && event->parent->pmu) {
11307 pmu = event->parent->pmu;
11308 ret = perf_try_init_event(pmu, event);
11314 * PERF_TYPE_HARDWARE and PERF_TYPE_HW_CACHE
11315 * are often aliases for PERF_TYPE_RAW.
11317 type = event->attr.type;
11318 if (type == PERF_TYPE_HARDWARE || type == PERF_TYPE_HW_CACHE) {
11319 type = event->attr.config >> PERF_PMU_TYPE_SHIFT;
11321 type = PERF_TYPE_RAW;
11323 extended_type = true;
11324 event->attr.config &= PERF_HW_EVENT_MASK;
11330 pmu = idr_find(&pmu_idr, type);
11333 if (event->attr.type != type && type != PERF_TYPE_RAW &&
11334 !(pmu->capabilities & PERF_PMU_CAP_EXTENDED_HW_TYPE))
11337 ret = perf_try_init_event(pmu, event);
11338 if (ret == -ENOENT && event->attr.type != type && !extended_type) {
11339 type = event->attr.type;
11344 pmu = ERR_PTR(ret);
11349 list_for_each_entry_rcu(pmu, &pmus, entry, lockdep_is_held(&pmus_srcu)) {
11350 ret = perf_try_init_event(pmu, event);
11354 if (ret != -ENOENT) {
11355 pmu = ERR_PTR(ret);
11360 pmu = ERR_PTR(-ENOENT);
11362 srcu_read_unlock(&pmus_srcu, idx);
11367 static void attach_sb_event(struct perf_event *event)
11369 struct pmu_event_list *pel = per_cpu_ptr(&pmu_sb_events, event->cpu);
11371 raw_spin_lock(&pel->lock);
11372 list_add_rcu(&event->sb_list, &pel->list);
11373 raw_spin_unlock(&pel->lock);
11377 * We keep a list of all !task (and therefore per-cpu) events
11378 * that need to receive side-band records.
11380 * This avoids having to scan all the various PMU per-cpu contexts
11381 * looking for them.
11383 static void account_pmu_sb_event(struct perf_event *event)
11385 if (is_sb_event(event))
11386 attach_sb_event(event);
11389 static void account_event_cpu(struct perf_event *event, int cpu)
11394 if (is_cgroup_event(event))
11395 atomic_inc(&per_cpu(perf_cgroup_events, cpu));
11398 /* Freq events need the tick to stay alive (see perf_event_task_tick). */
11399 static void account_freq_event_nohz(void)
11401 #ifdef CONFIG_NO_HZ_FULL
11402 /* Lock so we don't race with concurrent unaccount */
11403 spin_lock(&nr_freq_lock);
11404 if (atomic_inc_return(&nr_freq_events) == 1)
11405 tick_nohz_dep_set(TICK_DEP_BIT_PERF_EVENTS);
11406 spin_unlock(&nr_freq_lock);
11410 static void account_freq_event(void)
11412 if (tick_nohz_full_enabled())
11413 account_freq_event_nohz();
11415 atomic_inc(&nr_freq_events);
11419 static void account_event(struct perf_event *event)
11426 if (event->attach_state & (PERF_ATTACH_TASK | PERF_ATTACH_SCHED_CB))
11428 if (event->attr.mmap || event->attr.mmap_data)
11429 atomic_inc(&nr_mmap_events);
11430 if (event->attr.build_id)
11431 atomic_inc(&nr_build_id_events);
11432 if (event->attr.comm)
11433 atomic_inc(&nr_comm_events);
11434 if (event->attr.namespaces)
11435 atomic_inc(&nr_namespaces_events);
11436 if (event->attr.cgroup)
11437 atomic_inc(&nr_cgroup_events);
11438 if (event->attr.task)
11439 atomic_inc(&nr_task_events);
11440 if (event->attr.freq)
11441 account_freq_event();
11442 if (event->attr.context_switch) {
11443 atomic_inc(&nr_switch_events);
11446 if (has_branch_stack(event))
11448 if (is_cgroup_event(event))
11450 if (event->attr.ksymbol)
11451 atomic_inc(&nr_ksymbol_events);
11452 if (event->attr.bpf_event)
11453 atomic_inc(&nr_bpf_events);
11454 if (event->attr.text_poke)
11455 atomic_inc(&nr_text_poke_events);
11459 * We need the mutex here because static_branch_enable()
11460 * must complete *before* the perf_sched_count increment
11463 if (atomic_inc_not_zero(&perf_sched_count))
11466 mutex_lock(&perf_sched_mutex);
11467 if (!atomic_read(&perf_sched_count)) {
11468 static_branch_enable(&perf_sched_events);
11470 * Guarantee that all CPUs observe they key change and
11471 * call the perf scheduling hooks before proceeding to
11472 * install events that need them.
11477 * Now that we have waited for the sync_sched(), allow further
11478 * increments to by-pass the mutex.
11480 atomic_inc(&perf_sched_count);
11481 mutex_unlock(&perf_sched_mutex);
11485 account_event_cpu(event, event->cpu);
11487 account_pmu_sb_event(event);
11491 * Allocate and initialize an event structure
11493 static struct perf_event *
11494 perf_event_alloc(struct perf_event_attr *attr, int cpu,
11495 struct task_struct *task,
11496 struct perf_event *group_leader,
11497 struct perf_event *parent_event,
11498 perf_overflow_handler_t overflow_handler,
11499 void *context, int cgroup_fd)
11502 struct perf_event *event;
11503 struct hw_perf_event *hwc;
11504 long err = -EINVAL;
11507 if ((unsigned)cpu >= nr_cpu_ids) {
11508 if (!task || cpu != -1)
11509 return ERR_PTR(-EINVAL);
11511 if (attr->sigtrap && !task) {
11512 /* Requires a task: avoid signalling random tasks. */
11513 return ERR_PTR(-EINVAL);
11516 node = (cpu >= 0) ? cpu_to_node(cpu) : -1;
11517 event = kmem_cache_alloc_node(perf_event_cache, GFP_KERNEL | __GFP_ZERO,
11520 return ERR_PTR(-ENOMEM);
11523 * Single events are their own group leaders, with an
11524 * empty sibling list:
11527 group_leader = event;
11529 mutex_init(&event->child_mutex);
11530 INIT_LIST_HEAD(&event->child_list);
11532 INIT_LIST_HEAD(&event->event_entry);
11533 INIT_LIST_HEAD(&event->sibling_list);
11534 INIT_LIST_HEAD(&event->active_list);
11535 init_event_group(event);
11536 INIT_LIST_HEAD(&event->rb_entry);
11537 INIT_LIST_HEAD(&event->active_entry);
11538 INIT_LIST_HEAD(&event->addr_filters.list);
11539 INIT_HLIST_NODE(&event->hlist_entry);
11542 init_waitqueue_head(&event->waitq);
11543 event->pending_disable = -1;
11544 init_irq_work(&event->pending, perf_pending_event);
11546 mutex_init(&event->mmap_mutex);
11547 raw_spin_lock_init(&event->addr_filters.lock);
11549 atomic_long_set(&event->refcount, 1);
11551 event->attr = *attr;
11552 event->group_leader = group_leader;
11556 event->parent = parent_event;
11558 event->ns = get_pid_ns(task_active_pid_ns(current));
11559 event->id = atomic64_inc_return(&perf_event_id);
11561 event->state = PERF_EVENT_STATE_INACTIVE;
11563 if (event->attr.sigtrap)
11564 atomic_set(&event->event_limit, 1);
11567 event->attach_state = PERF_ATTACH_TASK;
11569 * XXX pmu::event_init needs to know what task to account to
11570 * and we cannot use the ctx information because we need the
11571 * pmu before we get a ctx.
11573 event->hw.target = get_task_struct(task);
11576 event->clock = &local_clock;
11578 event->clock = parent_event->clock;
11580 if (!overflow_handler && parent_event) {
11581 overflow_handler = parent_event->overflow_handler;
11582 context = parent_event->overflow_handler_context;
11583 #if defined(CONFIG_BPF_SYSCALL) && defined(CONFIG_EVENT_TRACING)
11584 if (overflow_handler == bpf_overflow_handler) {
11585 struct bpf_prog *prog = parent_event->prog;
11587 bpf_prog_inc(prog);
11588 event->prog = prog;
11589 event->orig_overflow_handler =
11590 parent_event->orig_overflow_handler;
11595 if (overflow_handler) {
11596 event->overflow_handler = overflow_handler;
11597 event->overflow_handler_context = context;
11598 } else if (is_write_backward(event)){
11599 event->overflow_handler = perf_event_output_backward;
11600 event->overflow_handler_context = NULL;
11602 event->overflow_handler = perf_event_output_forward;
11603 event->overflow_handler_context = NULL;
11606 perf_event__state_init(event);
11611 hwc->sample_period = attr->sample_period;
11612 if (attr->freq && attr->sample_freq)
11613 hwc->sample_period = 1;
11614 hwc->last_period = hwc->sample_period;
11616 local64_set(&hwc->period_left, hwc->sample_period);
11619 * We currently do not support PERF_SAMPLE_READ on inherited events.
11620 * See perf_output_read().
11622 if (attr->inherit && (attr->sample_type & PERF_SAMPLE_READ))
11625 if (!has_branch_stack(event))
11626 event->attr.branch_sample_type = 0;
11628 pmu = perf_init_event(event);
11630 err = PTR_ERR(pmu);
11635 * Disallow uncore-cgroup events, they don't make sense as the cgroup will
11636 * be different on other CPUs in the uncore mask.
11638 if (pmu->task_ctx_nr == perf_invalid_context && cgroup_fd != -1) {
11643 if (event->attr.aux_output &&
11644 !(pmu->capabilities & PERF_PMU_CAP_AUX_OUTPUT)) {
11649 if (cgroup_fd != -1) {
11650 err = perf_cgroup_connect(cgroup_fd, event, attr, group_leader);
11655 err = exclusive_event_init(event);
11659 if (has_addr_filter(event)) {
11660 event->addr_filter_ranges = kcalloc(pmu->nr_addr_filters,
11661 sizeof(struct perf_addr_filter_range),
11663 if (!event->addr_filter_ranges) {
11669 * Clone the parent's vma offsets: they are valid until exec()
11670 * even if the mm is not shared with the parent.
11672 if (event->parent) {
11673 struct perf_addr_filters_head *ifh = perf_event_addr_filters(event);
11675 raw_spin_lock_irq(&ifh->lock);
11676 memcpy(event->addr_filter_ranges,
11677 event->parent->addr_filter_ranges,
11678 pmu->nr_addr_filters * sizeof(struct perf_addr_filter_range));
11679 raw_spin_unlock_irq(&ifh->lock);
11682 /* force hw sync on the address filters */
11683 event->addr_filters_gen = 1;
11686 if (!event->parent) {
11687 if (event->attr.sample_type & PERF_SAMPLE_CALLCHAIN) {
11688 err = get_callchain_buffers(attr->sample_max_stack);
11690 goto err_addr_filters;
11694 err = security_perf_event_alloc(event);
11696 goto err_callchain_buffer;
11698 /* symmetric to unaccount_event() in _free_event() */
11699 account_event(event);
11703 err_callchain_buffer:
11704 if (!event->parent) {
11705 if (event->attr.sample_type & PERF_SAMPLE_CALLCHAIN)
11706 put_callchain_buffers();
11709 kfree(event->addr_filter_ranges);
11712 exclusive_event_destroy(event);
11715 if (is_cgroup_event(event))
11716 perf_detach_cgroup(event);
11717 if (event->destroy)
11718 event->destroy(event);
11719 module_put(pmu->module);
11722 put_pid_ns(event->ns);
11723 if (event->hw.target)
11724 put_task_struct(event->hw.target);
11725 kmem_cache_free(perf_event_cache, event);
11727 return ERR_PTR(err);
11730 static int perf_copy_attr(struct perf_event_attr __user *uattr,
11731 struct perf_event_attr *attr)
11736 /* Zero the full structure, so that a short copy will be nice. */
11737 memset(attr, 0, sizeof(*attr));
11739 ret = get_user(size, &uattr->size);
11743 /* ABI compatibility quirk: */
11745 size = PERF_ATTR_SIZE_VER0;
11746 if (size < PERF_ATTR_SIZE_VER0 || size > PAGE_SIZE)
11749 ret = copy_struct_from_user(attr, sizeof(*attr), uattr, size);
11758 if (attr->__reserved_1 || attr->__reserved_2 || attr->__reserved_3)
11761 if (attr->sample_type & ~(PERF_SAMPLE_MAX-1))
11764 if (attr->read_format & ~(PERF_FORMAT_MAX-1))
11767 if (attr->sample_type & PERF_SAMPLE_BRANCH_STACK) {
11768 u64 mask = attr->branch_sample_type;
11770 /* only using defined bits */
11771 if (mask & ~(PERF_SAMPLE_BRANCH_MAX-1))
11774 /* at least one branch bit must be set */
11775 if (!(mask & ~PERF_SAMPLE_BRANCH_PLM_ALL))
11778 /* propagate priv level, when not set for branch */
11779 if (!(mask & PERF_SAMPLE_BRANCH_PLM_ALL)) {
11781 /* exclude_kernel checked on syscall entry */
11782 if (!attr->exclude_kernel)
11783 mask |= PERF_SAMPLE_BRANCH_KERNEL;
11785 if (!attr->exclude_user)
11786 mask |= PERF_SAMPLE_BRANCH_USER;
11788 if (!attr->exclude_hv)
11789 mask |= PERF_SAMPLE_BRANCH_HV;
11791 * adjust user setting (for HW filter setup)
11793 attr->branch_sample_type = mask;
11795 /* privileged levels capture (kernel, hv): check permissions */
11796 if (mask & PERF_SAMPLE_BRANCH_PERM_PLM) {
11797 ret = perf_allow_kernel(attr);
11803 if (attr->sample_type & PERF_SAMPLE_REGS_USER) {
11804 ret = perf_reg_validate(attr->sample_regs_user);
11809 if (attr->sample_type & PERF_SAMPLE_STACK_USER) {
11810 if (!arch_perf_have_user_stack_dump())
11814 * We have __u32 type for the size, but so far
11815 * we can only use __u16 as maximum due to the
11816 * __u16 sample size limit.
11818 if (attr->sample_stack_user >= USHRT_MAX)
11820 else if (!IS_ALIGNED(attr->sample_stack_user, sizeof(u64)))
11824 if (!attr->sample_max_stack)
11825 attr->sample_max_stack = sysctl_perf_event_max_stack;
11827 if (attr->sample_type & PERF_SAMPLE_REGS_INTR)
11828 ret = perf_reg_validate(attr->sample_regs_intr);
11830 #ifndef CONFIG_CGROUP_PERF
11831 if (attr->sample_type & PERF_SAMPLE_CGROUP)
11834 if ((attr->sample_type & PERF_SAMPLE_WEIGHT) &&
11835 (attr->sample_type & PERF_SAMPLE_WEIGHT_STRUCT))
11838 if (!attr->inherit && attr->inherit_thread)
11841 if (attr->remove_on_exec && attr->enable_on_exec)
11844 if (attr->sigtrap && !attr->remove_on_exec)
11851 put_user(sizeof(*attr), &uattr->size);
11857 perf_event_set_output(struct perf_event *event, struct perf_event *output_event)
11859 struct perf_buffer *rb = NULL;
11865 /* don't allow circular references */
11866 if (event == output_event)
11870 * Don't allow cross-cpu buffers
11872 if (output_event->cpu != event->cpu)
11876 * If its not a per-cpu rb, it must be the same task.
11878 if (output_event->cpu == -1 && output_event->ctx != event->ctx)
11882 * Mixing clocks in the same buffer is trouble you don't need.
11884 if (output_event->clock != event->clock)
11888 * Either writing ring buffer from beginning or from end.
11889 * Mixing is not allowed.
11891 if (is_write_backward(output_event) != is_write_backward(event))
11895 * If both events generate aux data, they must be on the same PMU
11897 if (has_aux(event) && has_aux(output_event) &&
11898 event->pmu != output_event->pmu)
11902 mutex_lock(&event->mmap_mutex);
11903 /* Can't redirect output if we've got an active mmap() */
11904 if (atomic_read(&event->mmap_count))
11907 if (output_event) {
11908 /* get the rb we want to redirect to */
11909 rb = ring_buffer_get(output_event);
11914 ring_buffer_attach(event, rb);
11918 mutex_unlock(&event->mmap_mutex);
11924 static void mutex_lock_double(struct mutex *a, struct mutex *b)
11930 mutex_lock_nested(b, SINGLE_DEPTH_NESTING);
11933 static int perf_event_set_clock(struct perf_event *event, clockid_t clk_id)
11935 bool nmi_safe = false;
11938 case CLOCK_MONOTONIC:
11939 event->clock = &ktime_get_mono_fast_ns;
11943 case CLOCK_MONOTONIC_RAW:
11944 event->clock = &ktime_get_raw_fast_ns;
11948 case CLOCK_REALTIME:
11949 event->clock = &ktime_get_real_ns;
11952 case CLOCK_BOOTTIME:
11953 event->clock = &ktime_get_boottime_ns;
11957 event->clock = &ktime_get_clocktai_ns;
11964 if (!nmi_safe && !(event->pmu->capabilities & PERF_PMU_CAP_NO_NMI))
11971 * Variation on perf_event_ctx_lock_nested(), except we take two context
11974 static struct perf_event_context *
11975 __perf_event_ctx_lock_double(struct perf_event *group_leader,
11976 struct perf_event_context *ctx)
11978 struct perf_event_context *gctx;
11982 gctx = READ_ONCE(group_leader->ctx);
11983 if (!refcount_inc_not_zero(&gctx->refcount)) {
11989 mutex_lock_double(&gctx->mutex, &ctx->mutex);
11991 if (group_leader->ctx != gctx) {
11992 mutex_unlock(&ctx->mutex);
11993 mutex_unlock(&gctx->mutex);
12002 perf_check_permission(struct perf_event_attr *attr, struct task_struct *task)
12004 unsigned int ptrace_mode = PTRACE_MODE_READ_REALCREDS;
12005 bool is_capable = perfmon_capable();
12007 if (attr->sigtrap) {
12009 * perf_event_attr::sigtrap sends signals to the other task.
12010 * Require the current task to also have CAP_KILL.
12013 is_capable &= ns_capable(__task_cred(task)->user_ns, CAP_KILL);
12017 * If the required capabilities aren't available, checks for
12018 * ptrace permissions: upgrade to ATTACH, since sending signals
12019 * can effectively change the target task.
12021 ptrace_mode = PTRACE_MODE_ATTACH_REALCREDS;
12025 * Preserve ptrace permission check for backwards compatibility. The
12026 * ptrace check also includes checks that the current task and other
12027 * task have matching uids, and is therefore not done here explicitly.
12029 return is_capable || ptrace_may_access(task, ptrace_mode);
12033 * sys_perf_event_open - open a performance event, associate it to a task/cpu
12035 * @attr_uptr: event_id type attributes for monitoring/sampling
12038 * @group_fd: group leader event fd
12039 * @flags: perf event open flags
12041 SYSCALL_DEFINE5(perf_event_open,
12042 struct perf_event_attr __user *, attr_uptr,
12043 pid_t, pid, int, cpu, int, group_fd, unsigned long, flags)
12045 struct perf_event *group_leader = NULL, *output_event = NULL;
12046 struct perf_event *event, *sibling;
12047 struct perf_event_attr attr;
12048 struct perf_event_context *ctx, *gctx;
12049 struct file *event_file = NULL;
12050 struct fd group = {NULL, 0};
12051 struct task_struct *task = NULL;
12054 int move_group = 0;
12056 int f_flags = O_RDWR;
12057 int cgroup_fd = -1;
12059 /* for future expandability... */
12060 if (flags & ~PERF_FLAG_ALL)
12063 /* Do we allow access to perf_event_open(2) ? */
12064 err = security_perf_event_open(&attr, PERF_SECURITY_OPEN);
12068 err = perf_copy_attr(attr_uptr, &attr);
12072 if (!attr.exclude_kernel) {
12073 err = perf_allow_kernel(&attr);
12078 if (attr.namespaces) {
12079 if (!perfmon_capable())
12084 if (attr.sample_freq > sysctl_perf_event_sample_rate)
12087 if (attr.sample_period & (1ULL << 63))
12091 /* Only privileged users can get physical addresses */
12092 if ((attr.sample_type & PERF_SAMPLE_PHYS_ADDR)) {
12093 err = perf_allow_kernel(&attr);
12098 /* REGS_INTR can leak data, lockdown must prevent this */
12099 if (attr.sample_type & PERF_SAMPLE_REGS_INTR) {
12100 err = security_locked_down(LOCKDOWN_PERF);
12106 * In cgroup mode, the pid argument is used to pass the fd
12107 * opened to the cgroup directory in cgroupfs. The cpu argument
12108 * designates the cpu on which to monitor threads from that
12111 if ((flags & PERF_FLAG_PID_CGROUP) && (pid == -1 || cpu == -1))
12114 if (flags & PERF_FLAG_FD_CLOEXEC)
12115 f_flags |= O_CLOEXEC;
12117 event_fd = get_unused_fd_flags(f_flags);
12121 if (group_fd != -1) {
12122 err = perf_fget_light(group_fd, &group);
12125 group_leader = group.file->private_data;
12126 if (flags & PERF_FLAG_FD_OUTPUT)
12127 output_event = group_leader;
12128 if (flags & PERF_FLAG_FD_NO_GROUP)
12129 group_leader = NULL;
12132 if (pid != -1 && !(flags & PERF_FLAG_PID_CGROUP)) {
12133 task = find_lively_task_by_vpid(pid);
12134 if (IS_ERR(task)) {
12135 err = PTR_ERR(task);
12140 if (task && group_leader &&
12141 group_leader->attr.inherit != attr.inherit) {
12146 if (flags & PERF_FLAG_PID_CGROUP)
12149 event = perf_event_alloc(&attr, cpu, task, group_leader, NULL,
12150 NULL, NULL, cgroup_fd);
12151 if (IS_ERR(event)) {
12152 err = PTR_ERR(event);
12156 if (is_sampling_event(event)) {
12157 if (event->pmu->capabilities & PERF_PMU_CAP_NO_INTERRUPT) {
12164 * Special case software events and allow them to be part of
12165 * any hardware group.
12169 if (attr.use_clockid) {
12170 err = perf_event_set_clock(event, attr.clockid);
12175 if (pmu->task_ctx_nr == perf_sw_context)
12176 event->event_caps |= PERF_EV_CAP_SOFTWARE;
12178 if (group_leader) {
12179 if (is_software_event(event) &&
12180 !in_software_context(group_leader)) {
12182 * If the event is a sw event, but the group_leader
12183 * is on hw context.
12185 * Allow the addition of software events to hw
12186 * groups, this is safe because software events
12187 * never fail to schedule.
12189 pmu = group_leader->ctx->pmu;
12190 } else if (!is_software_event(event) &&
12191 is_software_event(group_leader) &&
12192 (group_leader->group_caps & PERF_EV_CAP_SOFTWARE)) {
12194 * In case the group is a pure software group, and we
12195 * try to add a hardware event, move the whole group to
12196 * the hardware context.
12203 * Get the target context (task or percpu):
12205 ctx = find_get_context(pmu, task, event);
12207 err = PTR_ERR(ctx);
12212 * Look up the group leader (we will attach this event to it):
12214 if (group_leader) {
12218 * Do not allow a recursive hierarchy (this new sibling
12219 * becoming part of another group-sibling):
12221 if (group_leader->group_leader != group_leader)
12224 /* All events in a group should have the same clock */
12225 if (group_leader->clock != event->clock)
12229 * Make sure we're both events for the same CPU;
12230 * grouping events for different CPUs is broken; since
12231 * you can never concurrently schedule them anyhow.
12233 if (group_leader->cpu != event->cpu)
12237 * Make sure we're both on the same task, or both
12240 if (group_leader->ctx->task != ctx->task)
12244 * Do not allow to attach to a group in a different task
12245 * or CPU context. If we're moving SW events, we'll fix
12246 * this up later, so allow that.
12248 if (!move_group && group_leader->ctx != ctx)
12252 * Only a group leader can be exclusive or pinned
12254 if (attr.exclusive || attr.pinned)
12258 if (output_event) {
12259 err = perf_event_set_output(event, output_event);
12264 event_file = anon_inode_getfile("[perf_event]", &perf_fops, event,
12266 if (IS_ERR(event_file)) {
12267 err = PTR_ERR(event_file);
12273 err = down_read_interruptible(&task->signal->exec_update_lock);
12278 * We must hold exec_update_lock across this and any potential
12279 * perf_install_in_context() call for this new event to
12280 * serialize against exec() altering our credentials (and the
12281 * perf_event_exit_task() that could imply).
12284 if (!perf_check_permission(&attr, task))
12289 gctx = __perf_event_ctx_lock_double(group_leader, ctx);
12291 if (gctx->task == TASK_TOMBSTONE) {
12297 * Check if we raced against another sys_perf_event_open() call
12298 * moving the software group underneath us.
12300 if (!(group_leader->group_caps & PERF_EV_CAP_SOFTWARE)) {
12302 * If someone moved the group out from under us, check
12303 * if this new event wound up on the same ctx, if so
12304 * its the regular !move_group case, otherwise fail.
12310 perf_event_ctx_unlock(group_leader, gctx);
12316 * Failure to create exclusive events returns -EBUSY.
12319 if (!exclusive_event_installable(group_leader, ctx))
12322 for_each_sibling_event(sibling, group_leader) {
12323 if (!exclusive_event_installable(sibling, ctx))
12327 mutex_lock(&ctx->mutex);
12330 if (ctx->task == TASK_TOMBSTONE) {
12335 if (!perf_event_validate_size(event)) {
12342 * Check if the @cpu we're creating an event for is online.
12344 * We use the perf_cpu_context::ctx::mutex to serialize against
12345 * the hotplug notifiers. See perf_event_{init,exit}_cpu().
12347 struct perf_cpu_context *cpuctx =
12348 container_of(ctx, struct perf_cpu_context, ctx);
12350 if (!cpuctx->online) {
12356 if (perf_need_aux_event(event) && !perf_get_aux_event(event, group_leader)) {
12362 * Must be under the same ctx::mutex as perf_install_in_context(),
12363 * because we need to serialize with concurrent event creation.
12365 if (!exclusive_event_installable(event, ctx)) {
12370 WARN_ON_ONCE(ctx->parent_ctx);
12373 * This is the point on no return; we cannot fail hereafter. This is
12374 * where we start modifying current state.
12379 * See perf_event_ctx_lock() for comments on the details
12380 * of swizzling perf_event::ctx.
12382 perf_remove_from_context(group_leader, 0);
12385 for_each_sibling_event(sibling, group_leader) {
12386 perf_remove_from_context(sibling, 0);
12391 * Wait for everybody to stop referencing the events through
12392 * the old lists, before installing it on new lists.
12397 * Install the group siblings before the group leader.
12399 * Because a group leader will try and install the entire group
12400 * (through the sibling list, which is still in-tact), we can
12401 * end up with siblings installed in the wrong context.
12403 * By installing siblings first we NO-OP because they're not
12404 * reachable through the group lists.
12406 for_each_sibling_event(sibling, group_leader) {
12407 perf_event__state_init(sibling);
12408 perf_install_in_context(ctx, sibling, sibling->cpu);
12413 * Removing from the context ends up with disabled
12414 * event. What we want here is event in the initial
12415 * startup state, ready to be add into new context.
12417 perf_event__state_init(group_leader);
12418 perf_install_in_context(ctx, group_leader, group_leader->cpu);
12423 * Precalculate sample_data sizes; do while holding ctx::mutex such
12424 * that we're serialized against further additions and before
12425 * perf_install_in_context() which is the point the event is active and
12426 * can use these values.
12428 perf_event__header_size(event);
12429 perf_event__id_header_size(event);
12431 event->owner = current;
12433 perf_install_in_context(ctx, event, event->cpu);
12434 perf_unpin_context(ctx);
12437 perf_event_ctx_unlock(group_leader, gctx);
12438 mutex_unlock(&ctx->mutex);
12441 up_read(&task->signal->exec_update_lock);
12442 put_task_struct(task);
12445 mutex_lock(¤t->perf_event_mutex);
12446 list_add_tail(&event->owner_entry, ¤t->perf_event_list);
12447 mutex_unlock(¤t->perf_event_mutex);
12450 * Drop the reference on the group_event after placing the
12451 * new event on the sibling_list. This ensures destruction
12452 * of the group leader will find the pointer to itself in
12453 * perf_group_detach().
12456 fd_install(event_fd, event_file);
12461 perf_event_ctx_unlock(group_leader, gctx);
12462 mutex_unlock(&ctx->mutex);
12465 up_read(&task->signal->exec_update_lock);
12469 perf_unpin_context(ctx);
12473 * If event_file is set, the fput() above will have called ->release()
12474 * and that will take care of freeing the event.
12480 put_task_struct(task);
12484 put_unused_fd(event_fd);
12489 * perf_event_create_kernel_counter
12491 * @attr: attributes of the counter to create
12492 * @cpu: cpu in which the counter is bound
12493 * @task: task to profile (NULL for percpu)
12494 * @overflow_handler: callback to trigger when we hit the event
12495 * @context: context data could be used in overflow_handler callback
12497 struct perf_event *
12498 perf_event_create_kernel_counter(struct perf_event_attr *attr, int cpu,
12499 struct task_struct *task,
12500 perf_overflow_handler_t overflow_handler,
12503 struct perf_event_context *ctx;
12504 struct perf_event *event;
12508 * Grouping is not supported for kernel events, neither is 'AUX',
12509 * make sure the caller's intentions are adjusted.
12511 if (attr->aux_output)
12512 return ERR_PTR(-EINVAL);
12514 event = perf_event_alloc(attr, cpu, task, NULL, NULL,
12515 overflow_handler, context, -1);
12516 if (IS_ERR(event)) {
12517 err = PTR_ERR(event);
12521 /* Mark owner so we could distinguish it from user events. */
12522 event->owner = TASK_TOMBSTONE;
12525 * Get the target context (task or percpu):
12527 ctx = find_get_context(event->pmu, task, event);
12529 err = PTR_ERR(ctx);
12533 WARN_ON_ONCE(ctx->parent_ctx);
12534 mutex_lock(&ctx->mutex);
12535 if (ctx->task == TASK_TOMBSTONE) {
12542 * Check if the @cpu we're creating an event for is online.
12544 * We use the perf_cpu_context::ctx::mutex to serialize against
12545 * the hotplug notifiers. See perf_event_{init,exit}_cpu().
12547 struct perf_cpu_context *cpuctx =
12548 container_of(ctx, struct perf_cpu_context, ctx);
12549 if (!cpuctx->online) {
12555 if (!exclusive_event_installable(event, ctx)) {
12560 perf_install_in_context(ctx, event, event->cpu);
12561 perf_unpin_context(ctx);
12562 mutex_unlock(&ctx->mutex);
12567 mutex_unlock(&ctx->mutex);
12568 perf_unpin_context(ctx);
12573 return ERR_PTR(err);
12575 EXPORT_SYMBOL_GPL(perf_event_create_kernel_counter);
12577 void perf_pmu_migrate_context(struct pmu *pmu, int src_cpu, int dst_cpu)
12579 struct perf_event_context *src_ctx;
12580 struct perf_event_context *dst_ctx;
12581 struct perf_event *event, *tmp;
12584 src_ctx = &per_cpu_ptr(pmu->pmu_cpu_context, src_cpu)->ctx;
12585 dst_ctx = &per_cpu_ptr(pmu->pmu_cpu_context, dst_cpu)->ctx;
12588 * See perf_event_ctx_lock() for comments on the details
12589 * of swizzling perf_event::ctx.
12591 mutex_lock_double(&src_ctx->mutex, &dst_ctx->mutex);
12592 list_for_each_entry_safe(event, tmp, &src_ctx->event_list,
12594 perf_remove_from_context(event, 0);
12595 unaccount_event_cpu(event, src_cpu);
12597 list_add(&event->migrate_entry, &events);
12601 * Wait for the events to quiesce before re-instating them.
12606 * Re-instate events in 2 passes.
12608 * Skip over group leaders and only install siblings on this first
12609 * pass, siblings will not get enabled without a leader, however a
12610 * leader will enable its siblings, even if those are still on the old
12613 list_for_each_entry_safe(event, tmp, &events, migrate_entry) {
12614 if (event->group_leader == event)
12617 list_del(&event->migrate_entry);
12618 if (event->state >= PERF_EVENT_STATE_OFF)
12619 event->state = PERF_EVENT_STATE_INACTIVE;
12620 account_event_cpu(event, dst_cpu);
12621 perf_install_in_context(dst_ctx, event, dst_cpu);
12626 * Once all the siblings are setup properly, install the group leaders
12629 list_for_each_entry_safe(event, tmp, &events, migrate_entry) {
12630 list_del(&event->migrate_entry);
12631 if (event->state >= PERF_EVENT_STATE_OFF)
12632 event->state = PERF_EVENT_STATE_INACTIVE;
12633 account_event_cpu(event, dst_cpu);
12634 perf_install_in_context(dst_ctx, event, dst_cpu);
12637 mutex_unlock(&dst_ctx->mutex);
12638 mutex_unlock(&src_ctx->mutex);
12640 EXPORT_SYMBOL_GPL(perf_pmu_migrate_context);
12642 static void sync_child_event(struct perf_event *child_event)
12644 struct perf_event *parent_event = child_event->parent;
12647 if (child_event->attr.inherit_stat) {
12648 struct task_struct *task = child_event->ctx->task;
12650 if (task && task != TASK_TOMBSTONE)
12651 perf_event_read_event(child_event, task);
12654 child_val = perf_event_count(child_event);
12657 * Add back the child's count to the parent's count:
12659 atomic64_add(child_val, &parent_event->child_count);
12660 atomic64_add(child_event->total_time_enabled,
12661 &parent_event->child_total_time_enabled);
12662 atomic64_add(child_event->total_time_running,
12663 &parent_event->child_total_time_running);
12667 perf_event_exit_event(struct perf_event *event, struct perf_event_context *ctx)
12669 struct perf_event *parent_event = event->parent;
12670 unsigned long detach_flags = 0;
12672 if (parent_event) {
12674 * Do not destroy the 'original' grouping; because of the
12675 * context switch optimization the original events could've
12676 * ended up in a random child task.
12678 * If we were to destroy the original group, all group related
12679 * operations would cease to function properly after this
12680 * random child dies.
12682 * Do destroy all inherited groups, we don't care about those
12683 * and being thorough is better.
12685 detach_flags = DETACH_GROUP | DETACH_CHILD;
12686 mutex_lock(&parent_event->child_mutex);
12689 perf_remove_from_context(event, detach_flags);
12691 raw_spin_lock_irq(&ctx->lock);
12692 if (event->state > PERF_EVENT_STATE_EXIT)
12693 perf_event_set_state(event, PERF_EVENT_STATE_EXIT);
12694 raw_spin_unlock_irq(&ctx->lock);
12697 * Child events can be freed.
12699 if (parent_event) {
12700 mutex_unlock(&parent_event->child_mutex);
12702 * Kick perf_poll() for is_event_hup();
12704 perf_event_wakeup(parent_event);
12706 put_event(parent_event);
12711 * Parent events are governed by their filedesc, retain them.
12713 perf_event_wakeup(event);
12716 static void perf_event_exit_task_context(struct task_struct *child, int ctxn)
12718 struct perf_event_context *child_ctx, *clone_ctx = NULL;
12719 struct perf_event *child_event, *next;
12721 WARN_ON_ONCE(child != current);
12723 child_ctx = perf_pin_task_context(child, ctxn);
12728 * In order to reduce the amount of tricky in ctx tear-down, we hold
12729 * ctx::mutex over the entire thing. This serializes against almost
12730 * everything that wants to access the ctx.
12732 * The exception is sys_perf_event_open() /
12733 * perf_event_create_kernel_count() which does find_get_context()
12734 * without ctx::mutex (it cannot because of the move_group double mutex
12735 * lock thing). See the comments in perf_install_in_context().
12737 mutex_lock(&child_ctx->mutex);
12740 * In a single ctx::lock section, de-schedule the events and detach the
12741 * context from the task such that we cannot ever get it scheduled back
12744 raw_spin_lock_irq(&child_ctx->lock);
12745 task_ctx_sched_out(__get_cpu_context(child_ctx), child_ctx, EVENT_ALL);
12748 * Now that the context is inactive, destroy the task <-> ctx relation
12749 * and mark the context dead.
12751 RCU_INIT_POINTER(child->perf_event_ctxp[ctxn], NULL);
12752 put_ctx(child_ctx); /* cannot be last */
12753 WRITE_ONCE(child_ctx->task, TASK_TOMBSTONE);
12754 put_task_struct(current); /* cannot be last */
12756 clone_ctx = unclone_ctx(child_ctx);
12757 raw_spin_unlock_irq(&child_ctx->lock);
12760 put_ctx(clone_ctx);
12763 * Report the task dead after unscheduling the events so that we
12764 * won't get any samples after PERF_RECORD_EXIT. We can however still
12765 * get a few PERF_RECORD_READ events.
12767 perf_event_task(child, child_ctx, 0);
12769 list_for_each_entry_safe(child_event, next, &child_ctx->event_list, event_entry)
12770 perf_event_exit_event(child_event, child_ctx);
12772 mutex_unlock(&child_ctx->mutex);
12774 put_ctx(child_ctx);
12778 * When a child task exits, feed back event values to parent events.
12780 * Can be called with exec_update_lock held when called from
12781 * setup_new_exec().
12783 void perf_event_exit_task(struct task_struct *child)
12785 struct perf_event *event, *tmp;
12788 mutex_lock(&child->perf_event_mutex);
12789 list_for_each_entry_safe(event, tmp, &child->perf_event_list,
12791 list_del_init(&event->owner_entry);
12794 * Ensure the list deletion is visible before we clear
12795 * the owner, closes a race against perf_release() where
12796 * we need to serialize on the owner->perf_event_mutex.
12798 smp_store_release(&event->owner, NULL);
12800 mutex_unlock(&child->perf_event_mutex);
12802 for_each_task_context_nr(ctxn)
12803 perf_event_exit_task_context(child, ctxn);
12806 * The perf_event_exit_task_context calls perf_event_task
12807 * with child's task_ctx, which generates EXIT events for
12808 * child contexts and sets child->perf_event_ctxp[] to NULL.
12809 * At this point we need to send EXIT events to cpu contexts.
12811 perf_event_task(child, NULL, 0);
12814 static void perf_free_event(struct perf_event *event,
12815 struct perf_event_context *ctx)
12817 struct perf_event *parent = event->parent;
12819 if (WARN_ON_ONCE(!parent))
12822 mutex_lock(&parent->child_mutex);
12823 list_del_init(&event->child_list);
12824 mutex_unlock(&parent->child_mutex);
12828 raw_spin_lock_irq(&ctx->lock);
12829 perf_group_detach(event);
12830 list_del_event(event, ctx);
12831 raw_spin_unlock_irq(&ctx->lock);
12836 * Free a context as created by inheritance by perf_event_init_task() below,
12837 * used by fork() in case of fail.
12839 * Even though the task has never lived, the context and events have been
12840 * exposed through the child_list, so we must take care tearing it all down.
12842 void perf_event_free_task(struct task_struct *task)
12844 struct perf_event_context *ctx;
12845 struct perf_event *event, *tmp;
12848 for_each_task_context_nr(ctxn) {
12849 ctx = task->perf_event_ctxp[ctxn];
12853 mutex_lock(&ctx->mutex);
12854 raw_spin_lock_irq(&ctx->lock);
12856 * Destroy the task <-> ctx relation and mark the context dead.
12858 * This is important because even though the task hasn't been
12859 * exposed yet the context has been (through child_list).
12861 RCU_INIT_POINTER(task->perf_event_ctxp[ctxn], NULL);
12862 WRITE_ONCE(ctx->task, TASK_TOMBSTONE);
12863 put_task_struct(task); /* cannot be last */
12864 raw_spin_unlock_irq(&ctx->lock);
12866 list_for_each_entry_safe(event, tmp, &ctx->event_list, event_entry)
12867 perf_free_event(event, ctx);
12869 mutex_unlock(&ctx->mutex);
12872 * perf_event_release_kernel() could've stolen some of our
12873 * child events and still have them on its free_list. In that
12874 * case we must wait for these events to have been freed (in
12875 * particular all their references to this task must've been
12878 * Without this copy_process() will unconditionally free this
12879 * task (irrespective of its reference count) and
12880 * _free_event()'s put_task_struct(event->hw.target) will be a
12883 * Wait for all events to drop their context reference.
12885 wait_var_event(&ctx->refcount, refcount_read(&ctx->refcount) == 1);
12886 put_ctx(ctx); /* must be last */
12890 void perf_event_delayed_put(struct task_struct *task)
12894 for_each_task_context_nr(ctxn)
12895 WARN_ON_ONCE(task->perf_event_ctxp[ctxn]);
12898 struct file *perf_event_get(unsigned int fd)
12900 struct file *file = fget(fd);
12902 return ERR_PTR(-EBADF);
12904 if (file->f_op != &perf_fops) {
12906 return ERR_PTR(-EBADF);
12912 const struct perf_event *perf_get_event(struct file *file)
12914 if (file->f_op != &perf_fops)
12915 return ERR_PTR(-EINVAL);
12917 return file->private_data;
12920 const struct perf_event_attr *perf_event_attrs(struct perf_event *event)
12923 return ERR_PTR(-EINVAL);
12925 return &event->attr;
12929 * Inherit an event from parent task to child task.
12932 * - valid pointer on success
12933 * - NULL for orphaned events
12934 * - IS_ERR() on error
12936 static struct perf_event *
12937 inherit_event(struct perf_event *parent_event,
12938 struct task_struct *parent,
12939 struct perf_event_context *parent_ctx,
12940 struct task_struct *child,
12941 struct perf_event *group_leader,
12942 struct perf_event_context *child_ctx)
12944 enum perf_event_state parent_state = parent_event->state;
12945 struct perf_event *child_event;
12946 unsigned long flags;
12949 * Instead of creating recursive hierarchies of events,
12950 * we link inherited events back to the original parent,
12951 * which has a filp for sure, which we use as the reference
12954 if (parent_event->parent)
12955 parent_event = parent_event->parent;
12957 child_event = perf_event_alloc(&parent_event->attr,
12960 group_leader, parent_event,
12962 if (IS_ERR(child_event))
12963 return child_event;
12966 if ((child_event->attach_state & PERF_ATTACH_TASK_DATA) &&
12967 !child_ctx->task_ctx_data) {
12968 struct pmu *pmu = child_event->pmu;
12970 child_ctx->task_ctx_data = alloc_task_ctx_data(pmu);
12971 if (!child_ctx->task_ctx_data) {
12972 free_event(child_event);
12973 return ERR_PTR(-ENOMEM);
12978 * is_orphaned_event() and list_add_tail(&parent_event->child_list)
12979 * must be under the same lock in order to serialize against
12980 * perf_event_release_kernel(), such that either we must observe
12981 * is_orphaned_event() or they will observe us on the child_list.
12983 mutex_lock(&parent_event->child_mutex);
12984 if (is_orphaned_event(parent_event) ||
12985 !atomic_long_inc_not_zero(&parent_event->refcount)) {
12986 mutex_unlock(&parent_event->child_mutex);
12987 /* task_ctx_data is freed with child_ctx */
12988 free_event(child_event);
12992 get_ctx(child_ctx);
12995 * Make the child state follow the state of the parent event,
12996 * not its attr.disabled bit. We hold the parent's mutex,
12997 * so we won't race with perf_event_{en, dis}able_family.
12999 if (parent_state >= PERF_EVENT_STATE_INACTIVE)
13000 child_event->state = PERF_EVENT_STATE_INACTIVE;
13002 child_event->state = PERF_EVENT_STATE_OFF;
13004 if (parent_event->attr.freq) {
13005 u64 sample_period = parent_event->hw.sample_period;
13006 struct hw_perf_event *hwc = &child_event->hw;
13008 hwc->sample_period = sample_period;
13009 hwc->last_period = sample_period;
13011 local64_set(&hwc->period_left, sample_period);
13014 child_event->ctx = child_ctx;
13015 child_event->overflow_handler = parent_event->overflow_handler;
13016 child_event->overflow_handler_context
13017 = parent_event->overflow_handler_context;
13020 * Precalculate sample_data sizes
13022 perf_event__header_size(child_event);
13023 perf_event__id_header_size(child_event);
13026 * Link it up in the child's context:
13028 raw_spin_lock_irqsave(&child_ctx->lock, flags);
13029 add_event_to_ctx(child_event, child_ctx);
13030 child_event->attach_state |= PERF_ATTACH_CHILD;
13031 raw_spin_unlock_irqrestore(&child_ctx->lock, flags);
13034 * Link this into the parent event's child list
13036 list_add_tail(&child_event->child_list, &parent_event->child_list);
13037 mutex_unlock(&parent_event->child_mutex);
13039 return child_event;
13043 * Inherits an event group.
13045 * This will quietly suppress orphaned events; !inherit_event() is not an error.
13046 * This matches with perf_event_release_kernel() removing all child events.
13052 static int inherit_group(struct perf_event *parent_event,
13053 struct task_struct *parent,
13054 struct perf_event_context *parent_ctx,
13055 struct task_struct *child,
13056 struct perf_event_context *child_ctx)
13058 struct perf_event *leader;
13059 struct perf_event *sub;
13060 struct perf_event *child_ctr;
13062 leader = inherit_event(parent_event, parent, parent_ctx,
13063 child, NULL, child_ctx);
13064 if (IS_ERR(leader))
13065 return PTR_ERR(leader);
13067 * @leader can be NULL here because of is_orphaned_event(). In this
13068 * case inherit_event() will create individual events, similar to what
13069 * perf_group_detach() would do anyway.
13071 for_each_sibling_event(sub, parent_event) {
13072 child_ctr = inherit_event(sub, parent, parent_ctx,
13073 child, leader, child_ctx);
13074 if (IS_ERR(child_ctr))
13075 return PTR_ERR(child_ctr);
13077 if (sub->aux_event == parent_event && child_ctr &&
13078 !perf_get_aux_event(child_ctr, leader))
13085 * Creates the child task context and tries to inherit the event-group.
13087 * Clears @inherited_all on !attr.inherited or error. Note that we'll leave
13088 * inherited_all set when we 'fail' to inherit an orphaned event; this is
13089 * consistent with perf_event_release_kernel() removing all child events.
13096 inherit_task_group(struct perf_event *event, struct task_struct *parent,
13097 struct perf_event_context *parent_ctx,
13098 struct task_struct *child, int ctxn,
13099 u64 clone_flags, int *inherited_all)
13102 struct perf_event_context *child_ctx;
13104 if (!event->attr.inherit ||
13105 (event->attr.inherit_thread && !(clone_flags & CLONE_THREAD)) ||
13106 /* Do not inherit if sigtrap and signal handlers were cleared. */
13107 (event->attr.sigtrap && (clone_flags & CLONE_CLEAR_SIGHAND))) {
13108 *inherited_all = 0;
13112 child_ctx = child->perf_event_ctxp[ctxn];
13115 * This is executed from the parent task context, so
13116 * inherit events that have been marked for cloning.
13117 * First allocate and initialize a context for the
13120 child_ctx = alloc_perf_context(parent_ctx->pmu, child);
13124 child->perf_event_ctxp[ctxn] = child_ctx;
13127 ret = inherit_group(event, parent, parent_ctx,
13131 *inherited_all = 0;
13137 * Initialize the perf_event context in task_struct
13139 static int perf_event_init_context(struct task_struct *child, int ctxn,
13142 struct perf_event_context *child_ctx, *parent_ctx;
13143 struct perf_event_context *cloned_ctx;
13144 struct perf_event *event;
13145 struct task_struct *parent = current;
13146 int inherited_all = 1;
13147 unsigned long flags;
13150 if (likely(!parent->perf_event_ctxp[ctxn]))
13154 * If the parent's context is a clone, pin it so it won't get
13155 * swapped under us.
13157 parent_ctx = perf_pin_task_context(parent, ctxn);
13162 * No need to check if parent_ctx != NULL here; since we saw
13163 * it non-NULL earlier, the only reason for it to become NULL
13164 * is if we exit, and since we're currently in the middle of
13165 * a fork we can't be exiting at the same time.
13169 * Lock the parent list. No need to lock the child - not PID
13170 * hashed yet and not running, so nobody can access it.
13172 mutex_lock(&parent_ctx->mutex);
13175 * We dont have to disable NMIs - we are only looking at
13176 * the list, not manipulating it:
13178 perf_event_groups_for_each(event, &parent_ctx->pinned_groups) {
13179 ret = inherit_task_group(event, parent, parent_ctx,
13180 child, ctxn, clone_flags,
13187 * We can't hold ctx->lock when iterating the ->flexible_group list due
13188 * to allocations, but we need to prevent rotation because
13189 * rotate_ctx() will change the list from interrupt context.
13191 raw_spin_lock_irqsave(&parent_ctx->lock, flags);
13192 parent_ctx->rotate_disable = 1;
13193 raw_spin_unlock_irqrestore(&parent_ctx->lock, flags);
13195 perf_event_groups_for_each(event, &parent_ctx->flexible_groups) {
13196 ret = inherit_task_group(event, parent, parent_ctx,
13197 child, ctxn, clone_flags,
13203 raw_spin_lock_irqsave(&parent_ctx->lock, flags);
13204 parent_ctx->rotate_disable = 0;
13206 child_ctx = child->perf_event_ctxp[ctxn];
13208 if (child_ctx && inherited_all) {
13210 * Mark the child context as a clone of the parent
13211 * context, or of whatever the parent is a clone of.
13213 * Note that if the parent is a clone, the holding of
13214 * parent_ctx->lock avoids it from being uncloned.
13216 cloned_ctx = parent_ctx->parent_ctx;
13218 child_ctx->parent_ctx = cloned_ctx;
13219 child_ctx->parent_gen = parent_ctx->parent_gen;
13221 child_ctx->parent_ctx = parent_ctx;
13222 child_ctx->parent_gen = parent_ctx->generation;
13224 get_ctx(child_ctx->parent_ctx);
13227 raw_spin_unlock_irqrestore(&parent_ctx->lock, flags);
13229 mutex_unlock(&parent_ctx->mutex);
13231 perf_unpin_context(parent_ctx);
13232 put_ctx(parent_ctx);
13238 * Initialize the perf_event context in task_struct
13240 int perf_event_init_task(struct task_struct *child, u64 clone_flags)
13244 memset(child->perf_event_ctxp, 0, sizeof(child->perf_event_ctxp));
13245 mutex_init(&child->perf_event_mutex);
13246 INIT_LIST_HEAD(&child->perf_event_list);
13248 for_each_task_context_nr(ctxn) {
13249 ret = perf_event_init_context(child, ctxn, clone_flags);
13251 perf_event_free_task(child);
13259 static void __init perf_event_init_all_cpus(void)
13261 struct swevent_htable *swhash;
13264 zalloc_cpumask_var(&perf_online_mask, GFP_KERNEL);
13266 for_each_possible_cpu(cpu) {
13267 swhash = &per_cpu(swevent_htable, cpu);
13268 mutex_init(&swhash->hlist_mutex);
13269 INIT_LIST_HEAD(&per_cpu(active_ctx_list, cpu));
13271 INIT_LIST_HEAD(&per_cpu(pmu_sb_events.list, cpu));
13272 raw_spin_lock_init(&per_cpu(pmu_sb_events.lock, cpu));
13274 #ifdef CONFIG_CGROUP_PERF
13275 INIT_LIST_HEAD(&per_cpu(cgrp_cpuctx_list, cpu));
13277 INIT_LIST_HEAD(&per_cpu(sched_cb_list, cpu));
13281 static void perf_swevent_init_cpu(unsigned int cpu)
13283 struct swevent_htable *swhash = &per_cpu(swevent_htable, cpu);
13285 mutex_lock(&swhash->hlist_mutex);
13286 if (swhash->hlist_refcount > 0 && !swevent_hlist_deref(swhash)) {
13287 struct swevent_hlist *hlist;
13289 hlist = kzalloc_node(sizeof(*hlist), GFP_KERNEL, cpu_to_node(cpu));
13291 rcu_assign_pointer(swhash->swevent_hlist, hlist);
13293 mutex_unlock(&swhash->hlist_mutex);
13296 #if defined CONFIG_HOTPLUG_CPU || defined CONFIG_KEXEC_CORE
13297 static void __perf_event_exit_context(void *__info)
13299 struct perf_event_context *ctx = __info;
13300 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
13301 struct perf_event *event;
13303 raw_spin_lock(&ctx->lock);
13304 ctx_sched_out(ctx, cpuctx, EVENT_TIME);
13305 list_for_each_entry(event, &ctx->event_list, event_entry)
13306 __perf_remove_from_context(event, cpuctx, ctx, (void *)DETACH_GROUP);
13307 raw_spin_unlock(&ctx->lock);
13310 static void perf_event_exit_cpu_context(int cpu)
13312 struct perf_cpu_context *cpuctx;
13313 struct perf_event_context *ctx;
13316 mutex_lock(&pmus_lock);
13317 list_for_each_entry(pmu, &pmus, entry) {
13318 cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
13319 ctx = &cpuctx->ctx;
13321 mutex_lock(&ctx->mutex);
13322 smp_call_function_single(cpu, __perf_event_exit_context, ctx, 1);
13323 cpuctx->online = 0;
13324 mutex_unlock(&ctx->mutex);
13326 cpumask_clear_cpu(cpu, perf_online_mask);
13327 mutex_unlock(&pmus_lock);
13331 static void perf_event_exit_cpu_context(int cpu) { }
13335 int perf_event_init_cpu(unsigned int cpu)
13337 struct perf_cpu_context *cpuctx;
13338 struct perf_event_context *ctx;
13341 perf_swevent_init_cpu(cpu);
13343 mutex_lock(&pmus_lock);
13344 cpumask_set_cpu(cpu, perf_online_mask);
13345 list_for_each_entry(pmu, &pmus, entry) {
13346 cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
13347 ctx = &cpuctx->ctx;
13349 mutex_lock(&ctx->mutex);
13350 cpuctx->online = 1;
13351 mutex_unlock(&ctx->mutex);
13353 mutex_unlock(&pmus_lock);
13358 int perf_event_exit_cpu(unsigned int cpu)
13360 perf_event_exit_cpu_context(cpu);
13365 perf_reboot(struct notifier_block *notifier, unsigned long val, void *v)
13369 for_each_online_cpu(cpu)
13370 perf_event_exit_cpu(cpu);
13376 * Run the perf reboot notifier at the very last possible moment so that
13377 * the generic watchdog code runs as long as possible.
13379 static struct notifier_block perf_reboot_notifier = {
13380 .notifier_call = perf_reboot,
13381 .priority = INT_MIN,
13384 void __init perf_event_init(void)
13388 idr_init(&pmu_idr);
13390 perf_event_init_all_cpus();
13391 init_srcu_struct(&pmus_srcu);
13392 perf_pmu_register(&perf_swevent, "software", PERF_TYPE_SOFTWARE);
13393 perf_pmu_register(&perf_cpu_clock, NULL, -1);
13394 perf_pmu_register(&perf_task_clock, NULL, -1);
13395 perf_tp_register();
13396 perf_event_init_cpu(smp_processor_id());
13397 register_reboot_notifier(&perf_reboot_notifier);
13399 ret = init_hw_breakpoint();
13400 WARN(ret, "hw_breakpoint initialization failed with: %d", ret);
13402 perf_event_cache = KMEM_CACHE(perf_event, SLAB_PANIC);
13405 * Build time assertion that we keep the data_head at the intended
13406 * location. IOW, validation we got the __reserved[] size right.
13408 BUILD_BUG_ON((offsetof(struct perf_event_mmap_page, data_head))
13412 ssize_t perf_event_sysfs_show(struct device *dev, struct device_attribute *attr,
13415 struct perf_pmu_events_attr *pmu_attr =
13416 container_of(attr, struct perf_pmu_events_attr, attr);
13418 if (pmu_attr->event_str)
13419 return sprintf(page, "%s\n", pmu_attr->event_str);
13423 EXPORT_SYMBOL_GPL(perf_event_sysfs_show);
13425 static int __init perf_event_sysfs_init(void)
13430 mutex_lock(&pmus_lock);
13432 ret = bus_register(&pmu_bus);
13436 list_for_each_entry(pmu, &pmus, entry) {
13437 if (!pmu->name || pmu->type < 0)
13440 ret = pmu_dev_alloc(pmu);
13441 WARN(ret, "Failed to register pmu: %s, reason %d\n", pmu->name, ret);
13443 pmu_bus_running = 1;
13447 mutex_unlock(&pmus_lock);
13451 device_initcall(perf_event_sysfs_init);
13453 #ifdef CONFIG_CGROUP_PERF
13454 static struct cgroup_subsys_state *
13455 perf_cgroup_css_alloc(struct cgroup_subsys_state *parent_css)
13457 struct perf_cgroup *jc;
13459 jc = kzalloc(sizeof(*jc), GFP_KERNEL);
13461 return ERR_PTR(-ENOMEM);
13463 jc->info = alloc_percpu(struct perf_cgroup_info);
13466 return ERR_PTR(-ENOMEM);
13472 static void perf_cgroup_css_free(struct cgroup_subsys_state *css)
13474 struct perf_cgroup *jc = container_of(css, struct perf_cgroup, css);
13476 free_percpu(jc->info);
13480 static int perf_cgroup_css_online(struct cgroup_subsys_state *css)
13482 perf_event_cgroup(css->cgroup);
13486 static int __perf_cgroup_move(void *info)
13488 struct task_struct *task = info;
13490 perf_cgroup_switch(task, PERF_CGROUP_SWOUT | PERF_CGROUP_SWIN);
13495 static void perf_cgroup_attach(struct cgroup_taskset *tset)
13497 struct task_struct *task;
13498 struct cgroup_subsys_state *css;
13500 cgroup_taskset_for_each(task, css, tset)
13501 task_function_call(task, __perf_cgroup_move, task);
13504 struct cgroup_subsys perf_event_cgrp_subsys = {
13505 .css_alloc = perf_cgroup_css_alloc,
13506 .css_free = perf_cgroup_css_free,
13507 .css_online = perf_cgroup_css_online,
13508 .attach = perf_cgroup_attach,
13510 * Implicitly enable on dfl hierarchy so that perf events can
13511 * always be filtered by cgroup2 path as long as perf_event
13512 * controller is not mounted on a legacy hierarchy.
13514 .implicit_on_dfl = true,
13517 #endif /* CONFIG_CGROUP_PERF */
13519 DEFINE_STATIC_CALL_RET0(perf_snapshot_branch_stack, perf_snapshot_branch_stack_t);