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);
678 * UP store-release, load-acquire
681 #define __store_release(ptr, val) \
684 WRITE_ONCE(*(ptr), (val)); \
687 #define __load_acquire(ptr) \
689 __unqual_scalar_typeof(*(ptr)) ___p = READ_ONCE(*(ptr)); \
694 #ifdef CONFIG_CGROUP_PERF
697 perf_cgroup_match(struct perf_event *event)
699 struct perf_event_context *ctx = event->ctx;
700 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
702 /* @event doesn't care about cgroup */
706 /* wants specific cgroup scope but @cpuctx isn't associated with any */
711 * Cgroup scoping is recursive. An event enabled for a cgroup is
712 * also enabled for all its descendant cgroups. If @cpuctx's
713 * cgroup is a descendant of @event's (the test covers identity
714 * case), it's a match.
716 return cgroup_is_descendant(cpuctx->cgrp->css.cgroup,
717 event->cgrp->css.cgroup);
720 static inline void perf_detach_cgroup(struct perf_event *event)
722 css_put(&event->cgrp->css);
726 static inline int is_cgroup_event(struct perf_event *event)
728 return event->cgrp != NULL;
731 static inline u64 perf_cgroup_event_time(struct perf_event *event)
733 struct perf_cgroup_info *t;
735 t = per_cpu_ptr(event->cgrp->info, event->cpu);
739 static inline u64 perf_cgroup_event_time_now(struct perf_event *event, u64 now)
741 struct perf_cgroup_info *t;
743 t = per_cpu_ptr(event->cgrp->info, event->cpu);
744 if (!__load_acquire(&t->active))
746 now += READ_ONCE(t->timeoffset);
750 static inline void __update_cgrp_time(struct perf_cgroup_info *info, u64 now, bool adv)
753 info->time += now - info->timestamp;
754 info->timestamp = now;
756 * see update_context_time()
758 WRITE_ONCE(info->timeoffset, info->time - info->timestamp);
761 static inline void update_cgrp_time_from_cpuctx(struct perf_cpu_context *cpuctx, bool final)
763 struct perf_cgroup *cgrp = cpuctx->cgrp;
764 struct cgroup_subsys_state *css;
765 struct perf_cgroup_info *info;
768 u64 now = perf_clock();
770 for (css = &cgrp->css; css; css = css->parent) {
771 cgrp = container_of(css, struct perf_cgroup, css);
772 info = this_cpu_ptr(cgrp->info);
774 __update_cgrp_time(info, now, true);
776 __store_release(&info->active, 0);
781 static inline void update_cgrp_time_from_event(struct perf_event *event)
783 struct perf_cgroup_info *info;
784 struct perf_cgroup *cgrp;
787 * ensure we access cgroup data only when needed and
788 * when we know the cgroup is pinned (css_get)
790 if (!is_cgroup_event(event))
793 cgrp = perf_cgroup_from_task(current, event->ctx);
795 * Do not update time when cgroup is not active
797 if (cgroup_is_descendant(cgrp->css.cgroup, event->cgrp->css.cgroup)) {
798 info = this_cpu_ptr(event->cgrp->info);
799 __update_cgrp_time(info, perf_clock(), true);
804 perf_cgroup_set_timestamp(struct task_struct *task,
805 struct perf_event_context *ctx)
807 struct perf_cgroup *cgrp;
808 struct perf_cgroup_info *info;
809 struct cgroup_subsys_state *css;
812 * ctx->lock held by caller
813 * ensure we do not access cgroup data
814 * unless we have the cgroup pinned (css_get)
816 if (!task || !ctx->nr_cgroups)
819 cgrp = perf_cgroup_from_task(task, ctx);
821 for (css = &cgrp->css; css; css = css->parent) {
822 cgrp = container_of(css, struct perf_cgroup, css);
823 info = this_cpu_ptr(cgrp->info);
824 __update_cgrp_time(info, ctx->timestamp, false);
825 __store_release(&info->active, 1);
829 static DEFINE_PER_CPU(struct list_head, cgrp_cpuctx_list);
831 #define PERF_CGROUP_SWOUT 0x1 /* cgroup switch out every event */
832 #define PERF_CGROUP_SWIN 0x2 /* cgroup switch in events based on task */
835 * reschedule events based on the cgroup constraint of task.
837 * mode SWOUT : schedule out everything
838 * mode SWIN : schedule in based on cgroup for next
840 static void perf_cgroup_switch(struct task_struct *task, int mode)
842 struct perf_cpu_context *cpuctx;
843 struct list_head *list;
847 * Disable interrupts and preemption to avoid this CPU's
848 * cgrp_cpuctx_entry to change under us.
850 local_irq_save(flags);
852 list = this_cpu_ptr(&cgrp_cpuctx_list);
853 list_for_each_entry(cpuctx, list, cgrp_cpuctx_entry) {
854 WARN_ON_ONCE(cpuctx->ctx.nr_cgroups == 0);
856 perf_ctx_lock(cpuctx, cpuctx->task_ctx);
857 perf_pmu_disable(cpuctx->ctx.pmu);
859 if (mode & PERF_CGROUP_SWOUT) {
860 cpu_ctx_sched_out(cpuctx, EVENT_ALL);
862 * must not be done before ctxswout due
863 * to event_filter_match() in event_sched_out()
868 if (mode & PERF_CGROUP_SWIN) {
869 WARN_ON_ONCE(cpuctx->cgrp);
871 * set cgrp before ctxsw in to allow
872 * event_filter_match() to not have to pass
874 * we pass the cpuctx->ctx to perf_cgroup_from_task()
875 * because cgorup events are only per-cpu
877 cpuctx->cgrp = perf_cgroup_from_task(task,
879 cpu_ctx_sched_in(cpuctx, EVENT_ALL, task);
881 perf_pmu_enable(cpuctx->ctx.pmu);
882 perf_ctx_unlock(cpuctx, cpuctx->task_ctx);
885 local_irq_restore(flags);
888 static inline void perf_cgroup_sched_out(struct task_struct *task,
889 struct task_struct *next)
891 struct perf_cgroup *cgrp1;
892 struct perf_cgroup *cgrp2 = NULL;
896 * we come here when we know perf_cgroup_events > 0
897 * we do not need to pass the ctx here because we know
898 * we are holding the rcu lock
900 cgrp1 = perf_cgroup_from_task(task, NULL);
901 cgrp2 = perf_cgroup_from_task(next, NULL);
904 * only schedule out current cgroup events if we know
905 * that we are switching to a different cgroup. Otherwise,
906 * do no touch the cgroup events.
909 perf_cgroup_switch(task, PERF_CGROUP_SWOUT);
914 static inline void perf_cgroup_sched_in(struct task_struct *prev,
915 struct task_struct *task)
917 struct perf_cgroup *cgrp1;
918 struct perf_cgroup *cgrp2 = NULL;
922 * we come here when we know perf_cgroup_events > 0
923 * we do not need to pass the ctx here because we know
924 * we are holding the rcu lock
926 cgrp1 = perf_cgroup_from_task(task, NULL);
927 cgrp2 = perf_cgroup_from_task(prev, NULL);
930 * only need to schedule in cgroup events if we are changing
931 * cgroup during ctxsw. Cgroup events were not scheduled
932 * out of ctxsw out if that was not the case.
935 perf_cgroup_switch(task, PERF_CGROUP_SWIN);
940 static int perf_cgroup_ensure_storage(struct perf_event *event,
941 struct cgroup_subsys_state *css)
943 struct perf_cpu_context *cpuctx;
944 struct perf_event **storage;
945 int cpu, heap_size, ret = 0;
948 * Allow storage to have sufficent space for an iterator for each
949 * possibly nested cgroup plus an iterator for events with no cgroup.
951 for (heap_size = 1; css; css = css->parent)
954 for_each_possible_cpu(cpu) {
955 cpuctx = per_cpu_ptr(event->pmu->pmu_cpu_context, cpu);
956 if (heap_size <= cpuctx->heap_size)
959 storage = kmalloc_node(heap_size * sizeof(struct perf_event *),
960 GFP_KERNEL, cpu_to_node(cpu));
966 raw_spin_lock_irq(&cpuctx->ctx.lock);
967 if (cpuctx->heap_size < heap_size) {
968 swap(cpuctx->heap, storage);
969 if (storage == cpuctx->heap_default)
971 cpuctx->heap_size = heap_size;
973 raw_spin_unlock_irq(&cpuctx->ctx.lock);
981 static inline int perf_cgroup_connect(int fd, struct perf_event *event,
982 struct perf_event_attr *attr,
983 struct perf_event *group_leader)
985 struct perf_cgroup *cgrp;
986 struct cgroup_subsys_state *css;
987 struct fd f = fdget(fd);
993 css = css_tryget_online_from_dir(f.file->f_path.dentry,
994 &perf_event_cgrp_subsys);
1000 ret = perf_cgroup_ensure_storage(event, css);
1004 cgrp = container_of(css, struct perf_cgroup, css);
1008 * all events in a group must monitor
1009 * the same cgroup because a task belongs
1010 * to only one perf cgroup at a time
1012 if (group_leader && group_leader->cgrp != cgrp) {
1013 perf_detach_cgroup(event);
1022 perf_cgroup_event_enable(struct perf_event *event, struct perf_event_context *ctx)
1024 struct perf_cpu_context *cpuctx;
1026 if (!is_cgroup_event(event))
1030 * Because cgroup events are always per-cpu events,
1031 * @ctx == &cpuctx->ctx.
1033 cpuctx = container_of(ctx, struct perf_cpu_context, ctx);
1036 * Since setting cpuctx->cgrp is conditional on the current @cgrp
1037 * matching the event's cgroup, we must do this for every new event,
1038 * because if the first would mismatch, the second would not try again
1039 * and we would leave cpuctx->cgrp unset.
1041 if (ctx->is_active && !cpuctx->cgrp) {
1042 struct perf_cgroup *cgrp = perf_cgroup_from_task(current, ctx);
1044 if (cgroup_is_descendant(cgrp->css.cgroup, event->cgrp->css.cgroup))
1045 cpuctx->cgrp = cgrp;
1048 if (ctx->nr_cgroups++)
1051 list_add(&cpuctx->cgrp_cpuctx_entry,
1052 per_cpu_ptr(&cgrp_cpuctx_list, event->cpu));
1056 perf_cgroup_event_disable(struct perf_event *event, struct perf_event_context *ctx)
1058 struct perf_cpu_context *cpuctx;
1060 if (!is_cgroup_event(event))
1064 * Because cgroup events are always per-cpu events,
1065 * @ctx == &cpuctx->ctx.
1067 cpuctx = container_of(ctx, struct perf_cpu_context, ctx);
1069 if (--ctx->nr_cgroups)
1072 if (ctx->is_active && cpuctx->cgrp)
1073 cpuctx->cgrp = NULL;
1075 list_del(&cpuctx->cgrp_cpuctx_entry);
1078 #else /* !CONFIG_CGROUP_PERF */
1081 perf_cgroup_match(struct perf_event *event)
1086 static inline void perf_detach_cgroup(struct perf_event *event)
1089 static inline int is_cgroup_event(struct perf_event *event)
1094 static inline void update_cgrp_time_from_event(struct perf_event *event)
1098 static inline void update_cgrp_time_from_cpuctx(struct perf_cpu_context *cpuctx,
1103 static inline void perf_cgroup_sched_out(struct task_struct *task,
1104 struct task_struct *next)
1108 static inline void perf_cgroup_sched_in(struct task_struct *prev,
1109 struct task_struct *task)
1113 static inline int perf_cgroup_connect(pid_t pid, struct perf_event *event,
1114 struct perf_event_attr *attr,
1115 struct perf_event *group_leader)
1121 perf_cgroup_set_timestamp(struct task_struct *task,
1122 struct perf_event_context *ctx)
1127 perf_cgroup_switch(struct task_struct *task, struct task_struct *next)
1131 static inline u64 perf_cgroup_event_time(struct perf_event *event)
1136 static inline u64 perf_cgroup_event_time_now(struct perf_event *event, u64 now)
1142 perf_cgroup_event_enable(struct perf_event *event, struct perf_event_context *ctx)
1147 perf_cgroup_event_disable(struct perf_event *event, struct perf_event_context *ctx)
1153 * set default to be dependent on timer tick just
1154 * like original code
1156 #define PERF_CPU_HRTIMER (1000 / HZ)
1158 * function must be called with interrupts disabled
1160 static enum hrtimer_restart perf_mux_hrtimer_handler(struct hrtimer *hr)
1162 struct perf_cpu_context *cpuctx;
1165 lockdep_assert_irqs_disabled();
1167 cpuctx = container_of(hr, struct perf_cpu_context, hrtimer);
1168 rotations = perf_rotate_context(cpuctx);
1170 raw_spin_lock(&cpuctx->hrtimer_lock);
1172 hrtimer_forward_now(hr, cpuctx->hrtimer_interval);
1174 cpuctx->hrtimer_active = 0;
1175 raw_spin_unlock(&cpuctx->hrtimer_lock);
1177 return rotations ? HRTIMER_RESTART : HRTIMER_NORESTART;
1180 static void __perf_mux_hrtimer_init(struct perf_cpu_context *cpuctx, int cpu)
1182 struct hrtimer *timer = &cpuctx->hrtimer;
1183 struct pmu *pmu = cpuctx->ctx.pmu;
1186 /* no multiplexing needed for SW PMU */
1187 if (pmu->task_ctx_nr == perf_sw_context)
1191 * check default is sane, if not set then force to
1192 * default interval (1/tick)
1194 interval = pmu->hrtimer_interval_ms;
1196 interval = pmu->hrtimer_interval_ms = PERF_CPU_HRTIMER;
1198 cpuctx->hrtimer_interval = ns_to_ktime(NSEC_PER_MSEC * interval);
1200 raw_spin_lock_init(&cpuctx->hrtimer_lock);
1201 hrtimer_init(timer, CLOCK_MONOTONIC, HRTIMER_MODE_ABS_PINNED_HARD);
1202 timer->function = perf_mux_hrtimer_handler;
1205 static int perf_mux_hrtimer_restart(struct perf_cpu_context *cpuctx)
1207 struct hrtimer *timer = &cpuctx->hrtimer;
1208 struct pmu *pmu = cpuctx->ctx.pmu;
1209 unsigned long flags;
1211 /* not for SW PMU */
1212 if (pmu->task_ctx_nr == perf_sw_context)
1215 raw_spin_lock_irqsave(&cpuctx->hrtimer_lock, flags);
1216 if (!cpuctx->hrtimer_active) {
1217 cpuctx->hrtimer_active = 1;
1218 hrtimer_forward_now(timer, cpuctx->hrtimer_interval);
1219 hrtimer_start_expires(timer, HRTIMER_MODE_ABS_PINNED_HARD);
1221 raw_spin_unlock_irqrestore(&cpuctx->hrtimer_lock, flags);
1226 void perf_pmu_disable(struct pmu *pmu)
1228 int *count = this_cpu_ptr(pmu->pmu_disable_count);
1230 pmu->pmu_disable(pmu);
1233 void perf_pmu_enable(struct pmu *pmu)
1235 int *count = this_cpu_ptr(pmu->pmu_disable_count);
1237 pmu->pmu_enable(pmu);
1240 static DEFINE_PER_CPU(struct list_head, active_ctx_list);
1243 * perf_event_ctx_activate(), perf_event_ctx_deactivate(), and
1244 * perf_event_task_tick() are fully serialized because they're strictly cpu
1245 * affine and perf_event_ctx{activate,deactivate} are called with IRQs
1246 * disabled, while perf_event_task_tick is called from IRQ context.
1248 static void perf_event_ctx_activate(struct perf_event_context *ctx)
1250 struct list_head *head = this_cpu_ptr(&active_ctx_list);
1252 lockdep_assert_irqs_disabled();
1254 WARN_ON(!list_empty(&ctx->active_ctx_list));
1256 list_add(&ctx->active_ctx_list, head);
1259 static void perf_event_ctx_deactivate(struct perf_event_context *ctx)
1261 lockdep_assert_irqs_disabled();
1263 WARN_ON(list_empty(&ctx->active_ctx_list));
1265 list_del_init(&ctx->active_ctx_list);
1268 static void get_ctx(struct perf_event_context *ctx)
1270 refcount_inc(&ctx->refcount);
1273 static void *alloc_task_ctx_data(struct pmu *pmu)
1275 if (pmu->task_ctx_cache)
1276 return kmem_cache_zalloc(pmu->task_ctx_cache, GFP_KERNEL);
1281 static void free_task_ctx_data(struct pmu *pmu, void *task_ctx_data)
1283 if (pmu->task_ctx_cache && task_ctx_data)
1284 kmem_cache_free(pmu->task_ctx_cache, task_ctx_data);
1287 static void free_ctx(struct rcu_head *head)
1289 struct perf_event_context *ctx;
1291 ctx = container_of(head, struct perf_event_context, rcu_head);
1292 free_task_ctx_data(ctx->pmu, ctx->task_ctx_data);
1296 static void put_ctx(struct perf_event_context *ctx)
1298 if (refcount_dec_and_test(&ctx->refcount)) {
1299 if (ctx->parent_ctx)
1300 put_ctx(ctx->parent_ctx);
1301 if (ctx->task && ctx->task != TASK_TOMBSTONE)
1302 put_task_struct(ctx->task);
1303 call_rcu(&ctx->rcu_head, free_ctx);
1308 * Because of perf_event::ctx migration in sys_perf_event_open::move_group and
1309 * perf_pmu_migrate_context() we need some magic.
1311 * Those places that change perf_event::ctx will hold both
1312 * perf_event_ctx::mutex of the 'old' and 'new' ctx value.
1314 * Lock ordering is by mutex address. There are two other sites where
1315 * perf_event_context::mutex nests and those are:
1317 * - perf_event_exit_task_context() [ child , 0 ]
1318 * perf_event_exit_event()
1319 * put_event() [ parent, 1 ]
1321 * - perf_event_init_context() [ parent, 0 ]
1322 * inherit_task_group()
1325 * perf_event_alloc()
1327 * perf_try_init_event() [ child , 1 ]
1329 * While it appears there is an obvious deadlock here -- the parent and child
1330 * nesting levels are inverted between the two. This is in fact safe because
1331 * life-time rules separate them. That is an exiting task cannot fork, and a
1332 * spawning task cannot (yet) exit.
1334 * But remember that these are parent<->child context relations, and
1335 * migration does not affect children, therefore these two orderings should not
1338 * The change in perf_event::ctx does not affect children (as claimed above)
1339 * because the sys_perf_event_open() case will install a new event and break
1340 * the ctx parent<->child relation, and perf_pmu_migrate_context() is only
1341 * concerned with cpuctx and that doesn't have children.
1343 * The places that change perf_event::ctx will issue:
1345 * perf_remove_from_context();
1346 * synchronize_rcu();
1347 * perf_install_in_context();
1349 * to affect the change. The remove_from_context() + synchronize_rcu() should
1350 * quiesce the event, after which we can install it in the new location. This
1351 * means that only external vectors (perf_fops, prctl) can perturb the event
1352 * while in transit. Therefore all such accessors should also acquire
1353 * perf_event_context::mutex to serialize against this.
1355 * However; because event->ctx can change while we're waiting to acquire
1356 * ctx->mutex we must be careful and use the below perf_event_ctx_lock()
1361 * task_struct::perf_event_mutex
1362 * perf_event_context::mutex
1363 * perf_event::child_mutex;
1364 * perf_event_context::lock
1365 * perf_event::mmap_mutex
1367 * perf_addr_filters_head::lock
1371 * cpuctx->mutex / perf_event_context::mutex
1373 static struct perf_event_context *
1374 perf_event_ctx_lock_nested(struct perf_event *event, int nesting)
1376 struct perf_event_context *ctx;
1380 ctx = READ_ONCE(event->ctx);
1381 if (!refcount_inc_not_zero(&ctx->refcount)) {
1387 mutex_lock_nested(&ctx->mutex, nesting);
1388 if (event->ctx != ctx) {
1389 mutex_unlock(&ctx->mutex);
1397 static inline struct perf_event_context *
1398 perf_event_ctx_lock(struct perf_event *event)
1400 return perf_event_ctx_lock_nested(event, 0);
1403 static void perf_event_ctx_unlock(struct perf_event *event,
1404 struct perf_event_context *ctx)
1406 mutex_unlock(&ctx->mutex);
1411 * This must be done under the ctx->lock, such as to serialize against
1412 * context_equiv(), therefore we cannot call put_ctx() since that might end up
1413 * calling scheduler related locks and ctx->lock nests inside those.
1415 static __must_check struct perf_event_context *
1416 unclone_ctx(struct perf_event_context *ctx)
1418 struct perf_event_context *parent_ctx = ctx->parent_ctx;
1420 lockdep_assert_held(&ctx->lock);
1423 ctx->parent_ctx = NULL;
1429 static u32 perf_event_pid_type(struct perf_event *event, struct task_struct *p,
1434 * only top level events have the pid namespace they were created in
1437 event = event->parent;
1439 nr = __task_pid_nr_ns(p, type, event->ns);
1440 /* avoid -1 if it is idle thread or runs in another ns */
1441 if (!nr && !pid_alive(p))
1446 static u32 perf_event_pid(struct perf_event *event, struct task_struct *p)
1448 return perf_event_pid_type(event, p, PIDTYPE_TGID);
1451 static u32 perf_event_tid(struct perf_event *event, struct task_struct *p)
1453 return perf_event_pid_type(event, p, PIDTYPE_PID);
1457 * If we inherit events we want to return the parent event id
1460 static u64 primary_event_id(struct perf_event *event)
1465 id = event->parent->id;
1471 * Get the perf_event_context for a task and lock it.
1473 * This has to cope with the fact that until it is locked,
1474 * the context could get moved to another task.
1476 static struct perf_event_context *
1477 perf_lock_task_context(struct task_struct *task, int ctxn, unsigned long *flags)
1479 struct perf_event_context *ctx;
1483 * One of the few rules of preemptible RCU is that one cannot do
1484 * rcu_read_unlock() while holding a scheduler (or nested) lock when
1485 * part of the read side critical section was irqs-enabled -- see
1486 * rcu_read_unlock_special().
1488 * Since ctx->lock nests under rq->lock we must ensure the entire read
1489 * side critical section has interrupts disabled.
1491 local_irq_save(*flags);
1493 ctx = rcu_dereference(task->perf_event_ctxp[ctxn]);
1496 * If this context is a clone of another, it might
1497 * get swapped for another underneath us by
1498 * perf_event_task_sched_out, though the
1499 * rcu_read_lock() protects us from any context
1500 * getting freed. Lock the context and check if it
1501 * got swapped before we could get the lock, and retry
1502 * if so. If we locked the right context, then it
1503 * can't get swapped on us any more.
1505 raw_spin_lock(&ctx->lock);
1506 if (ctx != rcu_dereference(task->perf_event_ctxp[ctxn])) {
1507 raw_spin_unlock(&ctx->lock);
1509 local_irq_restore(*flags);
1513 if (ctx->task == TASK_TOMBSTONE ||
1514 !refcount_inc_not_zero(&ctx->refcount)) {
1515 raw_spin_unlock(&ctx->lock);
1518 WARN_ON_ONCE(ctx->task != task);
1523 local_irq_restore(*flags);
1528 * Get the context for a task and increment its pin_count so it
1529 * can't get swapped to another task. This also increments its
1530 * reference count so that the context can't get freed.
1532 static struct perf_event_context *
1533 perf_pin_task_context(struct task_struct *task, int ctxn)
1535 struct perf_event_context *ctx;
1536 unsigned long flags;
1538 ctx = perf_lock_task_context(task, ctxn, &flags);
1541 raw_spin_unlock_irqrestore(&ctx->lock, flags);
1546 static void perf_unpin_context(struct perf_event_context *ctx)
1548 unsigned long flags;
1550 raw_spin_lock_irqsave(&ctx->lock, flags);
1552 raw_spin_unlock_irqrestore(&ctx->lock, flags);
1556 * Update the record of the current time in a context.
1558 static void __update_context_time(struct perf_event_context *ctx, bool adv)
1560 u64 now = perf_clock();
1563 ctx->time += now - ctx->timestamp;
1564 ctx->timestamp = now;
1567 * The above: time' = time + (now - timestamp), can be re-arranged
1568 * into: time` = now + (time - timestamp), which gives a single value
1569 * offset to compute future time without locks on.
1571 * See perf_event_time_now(), which can be used from NMI context where
1572 * it's (obviously) not possible to acquire ctx->lock in order to read
1573 * both the above values in a consistent manner.
1575 WRITE_ONCE(ctx->timeoffset, ctx->time - ctx->timestamp);
1578 static void update_context_time(struct perf_event_context *ctx)
1580 __update_context_time(ctx, true);
1583 static u64 perf_event_time(struct perf_event *event)
1585 struct perf_event_context *ctx = event->ctx;
1590 if (is_cgroup_event(event))
1591 return perf_cgroup_event_time(event);
1596 static u64 perf_event_time_now(struct perf_event *event, u64 now)
1598 struct perf_event_context *ctx = event->ctx;
1603 if (is_cgroup_event(event))
1604 return perf_cgroup_event_time_now(event, now);
1606 if (!(__load_acquire(&ctx->is_active) & EVENT_TIME))
1609 now += READ_ONCE(ctx->timeoffset);
1613 static enum event_type_t get_event_type(struct perf_event *event)
1615 struct perf_event_context *ctx = event->ctx;
1616 enum event_type_t event_type;
1618 lockdep_assert_held(&ctx->lock);
1621 * It's 'group type', really, because if our group leader is
1622 * pinned, so are we.
1624 if (event->group_leader != event)
1625 event = event->group_leader;
1627 event_type = event->attr.pinned ? EVENT_PINNED : EVENT_FLEXIBLE;
1629 event_type |= EVENT_CPU;
1635 * Helper function to initialize event group nodes.
1637 static void init_event_group(struct perf_event *event)
1639 RB_CLEAR_NODE(&event->group_node);
1640 event->group_index = 0;
1644 * Extract pinned or flexible groups from the context
1645 * based on event attrs bits.
1647 static struct perf_event_groups *
1648 get_event_groups(struct perf_event *event, struct perf_event_context *ctx)
1650 if (event->attr.pinned)
1651 return &ctx->pinned_groups;
1653 return &ctx->flexible_groups;
1657 * Helper function to initializes perf_event_group trees.
1659 static void perf_event_groups_init(struct perf_event_groups *groups)
1661 groups->tree = RB_ROOT;
1665 static inline struct cgroup *event_cgroup(const struct perf_event *event)
1667 struct cgroup *cgroup = NULL;
1669 #ifdef CONFIG_CGROUP_PERF
1671 cgroup = event->cgrp->css.cgroup;
1678 * Compare function for event groups;
1680 * Implements complex key that first sorts by CPU and then by virtual index
1681 * which provides ordering when rotating groups for the same CPU.
1683 static __always_inline int
1684 perf_event_groups_cmp(const int left_cpu, const struct cgroup *left_cgroup,
1685 const u64 left_group_index, const struct perf_event *right)
1687 if (left_cpu < right->cpu)
1689 if (left_cpu > right->cpu)
1692 #ifdef CONFIG_CGROUP_PERF
1694 const struct cgroup *right_cgroup = event_cgroup(right);
1696 if (left_cgroup != right_cgroup) {
1699 * Left has no cgroup but right does, no
1700 * cgroups come first.
1704 if (!right_cgroup) {
1706 * Right has no cgroup but left does, no
1707 * cgroups come first.
1711 /* Two dissimilar cgroups, order by id. */
1712 if (cgroup_id(left_cgroup) < cgroup_id(right_cgroup))
1720 if (left_group_index < right->group_index)
1722 if (left_group_index > right->group_index)
1728 #define __node_2_pe(node) \
1729 rb_entry((node), struct perf_event, group_node)
1731 static inline bool __group_less(struct rb_node *a, const struct rb_node *b)
1733 struct perf_event *e = __node_2_pe(a);
1734 return perf_event_groups_cmp(e->cpu, event_cgroup(e), e->group_index,
1735 __node_2_pe(b)) < 0;
1738 struct __group_key {
1740 struct cgroup *cgroup;
1743 static inline int __group_cmp(const void *key, const struct rb_node *node)
1745 const struct __group_key *a = key;
1746 const struct perf_event *b = __node_2_pe(node);
1748 /* partial/subtree match: @cpu, @cgroup; ignore: @group_index */
1749 return perf_event_groups_cmp(a->cpu, a->cgroup, b->group_index, b);
1753 * Insert @event into @groups' tree; using {@event->cpu, ++@groups->index} for
1754 * key (see perf_event_groups_less). This places it last inside the CPU
1758 perf_event_groups_insert(struct perf_event_groups *groups,
1759 struct perf_event *event)
1761 event->group_index = ++groups->index;
1763 rb_add(&event->group_node, &groups->tree, __group_less);
1767 * Helper function to insert event into the pinned or flexible groups.
1770 add_event_to_groups(struct perf_event *event, struct perf_event_context *ctx)
1772 struct perf_event_groups *groups;
1774 groups = get_event_groups(event, ctx);
1775 perf_event_groups_insert(groups, event);
1779 * Delete a group from a tree.
1782 perf_event_groups_delete(struct perf_event_groups *groups,
1783 struct perf_event *event)
1785 WARN_ON_ONCE(RB_EMPTY_NODE(&event->group_node) ||
1786 RB_EMPTY_ROOT(&groups->tree));
1788 rb_erase(&event->group_node, &groups->tree);
1789 init_event_group(event);
1793 * Helper function to delete event from its groups.
1796 del_event_from_groups(struct perf_event *event, struct perf_event_context *ctx)
1798 struct perf_event_groups *groups;
1800 groups = get_event_groups(event, ctx);
1801 perf_event_groups_delete(groups, event);
1805 * Get the leftmost event in the cpu/cgroup subtree.
1807 static struct perf_event *
1808 perf_event_groups_first(struct perf_event_groups *groups, int cpu,
1809 struct cgroup *cgrp)
1811 struct __group_key key = {
1815 struct rb_node *node;
1817 node = rb_find_first(&key, &groups->tree, __group_cmp);
1819 return __node_2_pe(node);
1825 * Like rb_entry_next_safe() for the @cpu subtree.
1827 static struct perf_event *
1828 perf_event_groups_next(struct perf_event *event)
1830 struct __group_key key = {
1832 .cgroup = event_cgroup(event),
1834 struct rb_node *next;
1836 next = rb_next_match(&key, &event->group_node, __group_cmp);
1838 return __node_2_pe(next);
1844 * Iterate through the whole groups tree.
1846 #define perf_event_groups_for_each(event, groups) \
1847 for (event = rb_entry_safe(rb_first(&((groups)->tree)), \
1848 typeof(*event), group_node); event; \
1849 event = rb_entry_safe(rb_next(&event->group_node), \
1850 typeof(*event), group_node))
1853 * Add an event from the lists for its context.
1854 * Must be called with ctx->mutex and ctx->lock held.
1857 list_add_event(struct perf_event *event, struct perf_event_context *ctx)
1859 lockdep_assert_held(&ctx->lock);
1861 WARN_ON_ONCE(event->attach_state & PERF_ATTACH_CONTEXT);
1862 event->attach_state |= PERF_ATTACH_CONTEXT;
1864 event->tstamp = perf_event_time(event);
1867 * If we're a stand alone event or group leader, we go to the context
1868 * list, group events are kept attached to the group so that
1869 * perf_group_detach can, at all times, locate all siblings.
1871 if (event->group_leader == event) {
1872 event->group_caps = event->event_caps;
1873 add_event_to_groups(event, ctx);
1876 list_add_rcu(&event->event_entry, &ctx->event_list);
1878 if (event->hw.flags & PERF_EVENT_FLAG_USER_READ_CNT)
1880 if (event->attr.inherit_stat)
1883 if (event->state > PERF_EVENT_STATE_OFF)
1884 perf_cgroup_event_enable(event, ctx);
1890 * Initialize event state based on the perf_event_attr::disabled.
1892 static inline void perf_event__state_init(struct perf_event *event)
1894 event->state = event->attr.disabled ? PERF_EVENT_STATE_OFF :
1895 PERF_EVENT_STATE_INACTIVE;
1898 static void __perf_event_read_size(struct perf_event *event, int nr_siblings)
1900 int entry = sizeof(u64); /* value */
1904 if (event->attr.read_format & PERF_FORMAT_TOTAL_TIME_ENABLED)
1905 size += sizeof(u64);
1907 if (event->attr.read_format & PERF_FORMAT_TOTAL_TIME_RUNNING)
1908 size += sizeof(u64);
1910 if (event->attr.read_format & PERF_FORMAT_ID)
1911 entry += sizeof(u64);
1913 if (event->attr.read_format & PERF_FORMAT_GROUP) {
1915 size += sizeof(u64);
1919 event->read_size = size;
1922 static void __perf_event_header_size(struct perf_event *event, u64 sample_type)
1924 struct perf_sample_data *data;
1927 if (sample_type & PERF_SAMPLE_IP)
1928 size += sizeof(data->ip);
1930 if (sample_type & PERF_SAMPLE_ADDR)
1931 size += sizeof(data->addr);
1933 if (sample_type & PERF_SAMPLE_PERIOD)
1934 size += sizeof(data->period);
1936 if (sample_type & PERF_SAMPLE_WEIGHT_TYPE)
1937 size += sizeof(data->weight.full);
1939 if (sample_type & PERF_SAMPLE_READ)
1940 size += event->read_size;
1942 if (sample_type & PERF_SAMPLE_DATA_SRC)
1943 size += sizeof(data->data_src.val);
1945 if (sample_type & PERF_SAMPLE_TRANSACTION)
1946 size += sizeof(data->txn);
1948 if (sample_type & PERF_SAMPLE_PHYS_ADDR)
1949 size += sizeof(data->phys_addr);
1951 if (sample_type & PERF_SAMPLE_CGROUP)
1952 size += sizeof(data->cgroup);
1954 if (sample_type & PERF_SAMPLE_DATA_PAGE_SIZE)
1955 size += sizeof(data->data_page_size);
1957 if (sample_type & PERF_SAMPLE_CODE_PAGE_SIZE)
1958 size += sizeof(data->code_page_size);
1960 event->header_size = size;
1964 * Called at perf_event creation and when events are attached/detached from a
1967 static void perf_event__header_size(struct perf_event *event)
1969 __perf_event_read_size(event,
1970 event->group_leader->nr_siblings);
1971 __perf_event_header_size(event, event->attr.sample_type);
1974 static void perf_event__id_header_size(struct perf_event *event)
1976 struct perf_sample_data *data;
1977 u64 sample_type = event->attr.sample_type;
1980 if (sample_type & PERF_SAMPLE_TID)
1981 size += sizeof(data->tid_entry);
1983 if (sample_type & PERF_SAMPLE_TIME)
1984 size += sizeof(data->time);
1986 if (sample_type & PERF_SAMPLE_IDENTIFIER)
1987 size += sizeof(data->id);
1989 if (sample_type & PERF_SAMPLE_ID)
1990 size += sizeof(data->id);
1992 if (sample_type & PERF_SAMPLE_STREAM_ID)
1993 size += sizeof(data->stream_id);
1995 if (sample_type & PERF_SAMPLE_CPU)
1996 size += sizeof(data->cpu_entry);
1998 event->id_header_size = size;
2001 static bool perf_event_validate_size(struct perf_event *event)
2004 * The values computed here will be over-written when we actually
2007 __perf_event_read_size(event, event->group_leader->nr_siblings + 1);
2008 __perf_event_header_size(event, event->attr.sample_type & ~PERF_SAMPLE_READ);
2009 perf_event__id_header_size(event);
2012 * Sum the lot; should not exceed the 64k limit we have on records.
2013 * Conservative limit to allow for callchains and other variable fields.
2015 if (event->read_size + event->header_size +
2016 event->id_header_size + sizeof(struct perf_event_header) >= 16*1024)
2022 static void perf_group_attach(struct perf_event *event)
2024 struct perf_event *group_leader = event->group_leader, *pos;
2026 lockdep_assert_held(&event->ctx->lock);
2029 * We can have double attach due to group movement in perf_event_open.
2031 if (event->attach_state & PERF_ATTACH_GROUP)
2034 event->attach_state |= PERF_ATTACH_GROUP;
2036 if (group_leader == event)
2039 WARN_ON_ONCE(group_leader->ctx != event->ctx);
2041 group_leader->group_caps &= event->event_caps;
2043 list_add_tail(&event->sibling_list, &group_leader->sibling_list);
2044 group_leader->nr_siblings++;
2046 perf_event__header_size(group_leader);
2048 for_each_sibling_event(pos, group_leader)
2049 perf_event__header_size(pos);
2053 * Remove an event from the lists for its context.
2054 * Must be called with ctx->mutex and ctx->lock held.
2057 list_del_event(struct perf_event *event, struct perf_event_context *ctx)
2059 WARN_ON_ONCE(event->ctx != ctx);
2060 lockdep_assert_held(&ctx->lock);
2063 * We can have double detach due to exit/hot-unplug + close.
2065 if (!(event->attach_state & PERF_ATTACH_CONTEXT))
2068 event->attach_state &= ~PERF_ATTACH_CONTEXT;
2071 if (event->hw.flags & PERF_EVENT_FLAG_USER_READ_CNT)
2073 if (event->attr.inherit_stat)
2076 list_del_rcu(&event->event_entry);
2078 if (event->group_leader == event)
2079 del_event_from_groups(event, ctx);
2082 * If event was in error state, then keep it
2083 * that way, otherwise bogus counts will be
2084 * returned on read(). The only way to get out
2085 * of error state is by explicit re-enabling
2088 if (event->state > PERF_EVENT_STATE_OFF) {
2089 perf_cgroup_event_disable(event, ctx);
2090 perf_event_set_state(event, PERF_EVENT_STATE_OFF);
2097 perf_aux_output_match(struct perf_event *event, struct perf_event *aux_event)
2099 if (!has_aux(aux_event))
2102 if (!event->pmu->aux_output_match)
2105 return event->pmu->aux_output_match(aux_event);
2108 static void put_event(struct perf_event *event);
2109 static void event_sched_out(struct perf_event *event,
2110 struct perf_cpu_context *cpuctx,
2111 struct perf_event_context *ctx);
2113 static void perf_put_aux_event(struct perf_event *event)
2115 struct perf_event_context *ctx = event->ctx;
2116 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
2117 struct perf_event *iter;
2120 * If event uses aux_event tear down the link
2122 if (event->aux_event) {
2123 iter = event->aux_event;
2124 event->aux_event = NULL;
2130 * If the event is an aux_event, tear down all links to
2131 * it from other events.
2133 for_each_sibling_event(iter, event->group_leader) {
2134 if (iter->aux_event != event)
2137 iter->aux_event = NULL;
2141 * If it's ACTIVE, schedule it out and put it into ERROR
2142 * state so that we don't try to schedule it again. Note
2143 * that perf_event_enable() will clear the ERROR status.
2145 event_sched_out(iter, cpuctx, ctx);
2146 perf_event_set_state(event, PERF_EVENT_STATE_ERROR);
2150 static bool perf_need_aux_event(struct perf_event *event)
2152 return !!event->attr.aux_output || !!event->attr.aux_sample_size;
2155 static int perf_get_aux_event(struct perf_event *event,
2156 struct perf_event *group_leader)
2159 * Our group leader must be an aux event if we want to be
2160 * an aux_output. This way, the aux event will precede its
2161 * aux_output events in the group, and therefore will always
2168 * aux_output and aux_sample_size are mutually exclusive.
2170 if (event->attr.aux_output && event->attr.aux_sample_size)
2173 if (event->attr.aux_output &&
2174 !perf_aux_output_match(event, group_leader))
2177 if (event->attr.aux_sample_size && !group_leader->pmu->snapshot_aux)
2180 if (!atomic_long_inc_not_zero(&group_leader->refcount))
2184 * Link aux_outputs to their aux event; this is undone in
2185 * perf_group_detach() by perf_put_aux_event(). When the
2186 * group in torn down, the aux_output events loose their
2187 * link to the aux_event and can't schedule any more.
2189 event->aux_event = group_leader;
2194 static inline struct list_head *get_event_list(struct perf_event *event)
2196 struct perf_event_context *ctx = event->ctx;
2197 return event->attr.pinned ? &ctx->pinned_active : &ctx->flexible_active;
2201 * Events that have PERF_EV_CAP_SIBLING require being part of a group and
2202 * cannot exist on their own, schedule them out and move them into the ERROR
2203 * state. Also see _perf_event_enable(), it will not be able to recover
2206 static inline void perf_remove_sibling_event(struct perf_event *event)
2208 struct perf_event_context *ctx = event->ctx;
2209 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
2211 event_sched_out(event, cpuctx, ctx);
2212 perf_event_set_state(event, PERF_EVENT_STATE_ERROR);
2215 static void perf_group_detach(struct perf_event *event)
2217 struct perf_event *leader = event->group_leader;
2218 struct perf_event *sibling, *tmp;
2219 struct perf_event_context *ctx = event->ctx;
2221 lockdep_assert_held(&ctx->lock);
2224 * We can have double detach due to exit/hot-unplug + close.
2226 if (!(event->attach_state & PERF_ATTACH_GROUP))
2229 event->attach_state &= ~PERF_ATTACH_GROUP;
2231 perf_put_aux_event(event);
2234 * If this is a sibling, remove it from its group.
2236 if (leader != event) {
2237 list_del_init(&event->sibling_list);
2238 event->group_leader->nr_siblings--;
2243 * If this was a group event with sibling events then
2244 * upgrade the siblings to singleton events by adding them
2245 * to whatever list we are on.
2247 list_for_each_entry_safe(sibling, tmp, &event->sibling_list, sibling_list) {
2249 if (sibling->event_caps & PERF_EV_CAP_SIBLING)
2250 perf_remove_sibling_event(sibling);
2252 sibling->group_leader = sibling;
2253 list_del_init(&sibling->sibling_list);
2255 /* Inherit group flags from the previous leader */
2256 sibling->group_caps = event->group_caps;
2258 if (!RB_EMPTY_NODE(&event->group_node)) {
2259 add_event_to_groups(sibling, event->ctx);
2261 if (sibling->state == PERF_EVENT_STATE_ACTIVE)
2262 list_add_tail(&sibling->active_list, get_event_list(sibling));
2265 WARN_ON_ONCE(sibling->ctx != event->ctx);
2269 for_each_sibling_event(tmp, leader)
2270 perf_event__header_size(tmp);
2272 perf_event__header_size(leader);
2275 static void sync_child_event(struct perf_event *child_event);
2277 static void perf_child_detach(struct perf_event *event)
2279 struct perf_event *parent_event = event->parent;
2281 if (!(event->attach_state & PERF_ATTACH_CHILD))
2284 event->attach_state &= ~PERF_ATTACH_CHILD;
2286 if (WARN_ON_ONCE(!parent_event))
2289 lockdep_assert_held(&parent_event->child_mutex);
2291 sync_child_event(event);
2292 list_del_init(&event->child_list);
2295 static bool is_orphaned_event(struct perf_event *event)
2297 return event->state == PERF_EVENT_STATE_DEAD;
2300 static inline int __pmu_filter_match(struct perf_event *event)
2302 struct pmu *pmu = event->pmu;
2303 return pmu->filter_match ? pmu->filter_match(event) : 1;
2307 * Check whether we should attempt to schedule an event group based on
2308 * PMU-specific filtering. An event group can consist of HW and SW events,
2309 * potentially with a SW leader, so we must check all the filters, to
2310 * determine whether a group is schedulable:
2312 static inline int pmu_filter_match(struct perf_event *event)
2314 struct perf_event *sibling;
2316 if (!__pmu_filter_match(event))
2319 for_each_sibling_event(sibling, event) {
2320 if (!__pmu_filter_match(sibling))
2328 event_filter_match(struct perf_event *event)
2330 return (event->cpu == -1 || event->cpu == smp_processor_id()) &&
2331 perf_cgroup_match(event) && pmu_filter_match(event);
2335 event_sched_out(struct perf_event *event,
2336 struct perf_cpu_context *cpuctx,
2337 struct perf_event_context *ctx)
2339 enum perf_event_state state = PERF_EVENT_STATE_INACTIVE;
2341 WARN_ON_ONCE(event->ctx != ctx);
2342 lockdep_assert_held(&ctx->lock);
2344 if (event->state != PERF_EVENT_STATE_ACTIVE)
2348 * Asymmetry; we only schedule events _IN_ through ctx_sched_in(), but
2349 * we can schedule events _OUT_ individually through things like
2350 * __perf_remove_from_context().
2352 list_del_init(&event->active_list);
2354 perf_pmu_disable(event->pmu);
2356 event->pmu->del(event, 0);
2359 if (READ_ONCE(event->pending_disable) >= 0) {
2360 WRITE_ONCE(event->pending_disable, -1);
2361 perf_cgroup_event_disable(event, ctx);
2362 state = PERF_EVENT_STATE_OFF;
2364 perf_event_set_state(event, state);
2366 if (!is_software_event(event))
2367 cpuctx->active_oncpu--;
2368 if (!--ctx->nr_active)
2369 perf_event_ctx_deactivate(ctx);
2370 if (event->attr.freq && event->attr.sample_freq)
2372 if (event->attr.exclusive || !cpuctx->active_oncpu)
2373 cpuctx->exclusive = 0;
2375 perf_pmu_enable(event->pmu);
2379 group_sched_out(struct perf_event *group_event,
2380 struct perf_cpu_context *cpuctx,
2381 struct perf_event_context *ctx)
2383 struct perf_event *event;
2385 if (group_event->state != PERF_EVENT_STATE_ACTIVE)
2388 perf_pmu_disable(ctx->pmu);
2390 event_sched_out(group_event, cpuctx, ctx);
2393 * Schedule out siblings (if any):
2395 for_each_sibling_event(event, group_event)
2396 event_sched_out(event, cpuctx, ctx);
2398 perf_pmu_enable(ctx->pmu);
2401 #define DETACH_GROUP 0x01UL
2402 #define DETACH_CHILD 0x02UL
2405 * Cross CPU call to remove a performance event
2407 * We disable the event on the hardware level first. After that we
2408 * remove it from the context list.
2411 __perf_remove_from_context(struct perf_event *event,
2412 struct perf_cpu_context *cpuctx,
2413 struct perf_event_context *ctx,
2416 unsigned long flags = (unsigned long)info;
2418 if (ctx->is_active & EVENT_TIME) {
2419 update_context_time(ctx);
2420 update_cgrp_time_from_cpuctx(cpuctx, false);
2423 event_sched_out(event, cpuctx, ctx);
2424 if (flags & DETACH_GROUP)
2425 perf_group_detach(event);
2426 if (flags & DETACH_CHILD)
2427 perf_child_detach(event);
2428 list_del_event(event, ctx);
2430 if (!ctx->nr_events && ctx->is_active) {
2431 if (ctx == &cpuctx->ctx)
2432 update_cgrp_time_from_cpuctx(cpuctx, true);
2435 ctx->rotate_necessary = 0;
2437 WARN_ON_ONCE(cpuctx->task_ctx != ctx);
2438 cpuctx->task_ctx = NULL;
2444 * Remove the event from a task's (or a CPU's) list of events.
2446 * If event->ctx is a cloned context, callers must make sure that
2447 * every task struct that event->ctx->task could possibly point to
2448 * remains valid. This is OK when called from perf_release since
2449 * that only calls us on the top-level context, which can't be a clone.
2450 * When called from perf_event_exit_task, it's OK because the
2451 * context has been detached from its task.
2453 static void perf_remove_from_context(struct perf_event *event, unsigned long flags)
2455 struct perf_event_context *ctx = event->ctx;
2457 lockdep_assert_held(&ctx->mutex);
2460 * Because of perf_event_exit_task(), perf_remove_from_context() ought
2461 * to work in the face of TASK_TOMBSTONE, unlike every other
2462 * event_function_call() user.
2464 raw_spin_lock_irq(&ctx->lock);
2465 if (!ctx->is_active) {
2466 __perf_remove_from_context(event, __get_cpu_context(ctx),
2467 ctx, (void *)flags);
2468 raw_spin_unlock_irq(&ctx->lock);
2471 raw_spin_unlock_irq(&ctx->lock);
2473 event_function_call(event, __perf_remove_from_context, (void *)flags);
2477 * Cross CPU call to disable a performance event
2479 static void __perf_event_disable(struct perf_event *event,
2480 struct perf_cpu_context *cpuctx,
2481 struct perf_event_context *ctx,
2484 if (event->state < PERF_EVENT_STATE_INACTIVE)
2487 if (ctx->is_active & EVENT_TIME) {
2488 update_context_time(ctx);
2489 update_cgrp_time_from_event(event);
2492 if (event == event->group_leader)
2493 group_sched_out(event, cpuctx, ctx);
2495 event_sched_out(event, cpuctx, ctx);
2497 perf_event_set_state(event, PERF_EVENT_STATE_OFF);
2498 perf_cgroup_event_disable(event, ctx);
2504 * If event->ctx is a cloned context, callers must make sure that
2505 * every task struct that event->ctx->task could possibly point to
2506 * remains valid. This condition is satisfied when called through
2507 * perf_event_for_each_child or perf_event_for_each because they
2508 * hold the top-level event's child_mutex, so any descendant that
2509 * goes to exit will block in perf_event_exit_event().
2511 * When called from perf_pending_event it's OK because event->ctx
2512 * is the current context on this CPU and preemption is disabled,
2513 * hence we can't get into perf_event_task_sched_out for this context.
2515 static void _perf_event_disable(struct perf_event *event)
2517 struct perf_event_context *ctx = event->ctx;
2519 raw_spin_lock_irq(&ctx->lock);
2520 if (event->state <= PERF_EVENT_STATE_OFF) {
2521 raw_spin_unlock_irq(&ctx->lock);
2524 raw_spin_unlock_irq(&ctx->lock);
2526 event_function_call(event, __perf_event_disable, NULL);
2529 void perf_event_disable_local(struct perf_event *event)
2531 event_function_local(event, __perf_event_disable, NULL);
2535 * Strictly speaking kernel users cannot create groups and therefore this
2536 * interface does not need the perf_event_ctx_lock() magic.
2538 void perf_event_disable(struct perf_event *event)
2540 struct perf_event_context *ctx;
2542 ctx = perf_event_ctx_lock(event);
2543 _perf_event_disable(event);
2544 perf_event_ctx_unlock(event, ctx);
2546 EXPORT_SYMBOL_GPL(perf_event_disable);
2548 void perf_event_disable_inatomic(struct perf_event *event)
2550 WRITE_ONCE(event->pending_disable, smp_processor_id());
2551 /* can fail, see perf_pending_event_disable() */
2552 irq_work_queue(&event->pending);
2555 #define MAX_INTERRUPTS (~0ULL)
2557 static void perf_log_throttle(struct perf_event *event, int enable);
2558 static void perf_log_itrace_start(struct perf_event *event);
2561 event_sched_in(struct perf_event *event,
2562 struct perf_cpu_context *cpuctx,
2563 struct perf_event_context *ctx)
2567 WARN_ON_ONCE(event->ctx != ctx);
2569 lockdep_assert_held(&ctx->lock);
2571 if (event->state <= PERF_EVENT_STATE_OFF)
2574 WRITE_ONCE(event->oncpu, smp_processor_id());
2576 * Order event::oncpu write to happen before the ACTIVE state is
2577 * visible. This allows perf_event_{stop,read}() to observe the correct
2578 * ->oncpu if it sees ACTIVE.
2581 perf_event_set_state(event, PERF_EVENT_STATE_ACTIVE);
2584 * Unthrottle events, since we scheduled we might have missed several
2585 * ticks already, also for a heavily scheduling task there is little
2586 * guarantee it'll get a tick in a timely manner.
2588 if (unlikely(event->hw.interrupts == MAX_INTERRUPTS)) {
2589 perf_log_throttle(event, 1);
2590 event->hw.interrupts = 0;
2593 perf_pmu_disable(event->pmu);
2595 perf_log_itrace_start(event);
2597 if (event->pmu->add(event, PERF_EF_START)) {
2598 perf_event_set_state(event, PERF_EVENT_STATE_INACTIVE);
2604 if (!is_software_event(event))
2605 cpuctx->active_oncpu++;
2606 if (!ctx->nr_active++)
2607 perf_event_ctx_activate(ctx);
2608 if (event->attr.freq && event->attr.sample_freq)
2611 if (event->attr.exclusive)
2612 cpuctx->exclusive = 1;
2615 perf_pmu_enable(event->pmu);
2621 group_sched_in(struct perf_event *group_event,
2622 struct perf_cpu_context *cpuctx,
2623 struct perf_event_context *ctx)
2625 struct perf_event *event, *partial_group = NULL;
2626 struct pmu *pmu = ctx->pmu;
2628 if (group_event->state == PERF_EVENT_STATE_OFF)
2631 pmu->start_txn(pmu, PERF_PMU_TXN_ADD);
2633 if (event_sched_in(group_event, cpuctx, ctx))
2637 * Schedule in siblings as one group (if any):
2639 for_each_sibling_event(event, group_event) {
2640 if (event_sched_in(event, cpuctx, ctx)) {
2641 partial_group = event;
2646 if (!pmu->commit_txn(pmu))
2651 * Groups can be scheduled in as one unit only, so undo any
2652 * partial group before returning:
2653 * The events up to the failed event are scheduled out normally.
2655 for_each_sibling_event(event, group_event) {
2656 if (event == partial_group)
2659 event_sched_out(event, cpuctx, ctx);
2661 event_sched_out(group_event, cpuctx, ctx);
2664 pmu->cancel_txn(pmu);
2669 * Work out whether we can put this event group on the CPU now.
2671 static int group_can_go_on(struct perf_event *event,
2672 struct perf_cpu_context *cpuctx,
2676 * Groups consisting entirely of software events can always go on.
2678 if (event->group_caps & PERF_EV_CAP_SOFTWARE)
2681 * If an exclusive group is already on, no other hardware
2684 if (cpuctx->exclusive)
2687 * If this group is exclusive and there are already
2688 * events on the CPU, it can't go on.
2690 if (event->attr.exclusive && !list_empty(get_event_list(event)))
2693 * Otherwise, try to add it if all previous groups were able
2699 static void add_event_to_ctx(struct perf_event *event,
2700 struct perf_event_context *ctx)
2702 list_add_event(event, ctx);
2703 perf_group_attach(event);
2706 static void ctx_sched_out(struct perf_event_context *ctx,
2707 struct perf_cpu_context *cpuctx,
2708 enum event_type_t event_type);
2710 ctx_sched_in(struct perf_event_context *ctx,
2711 struct perf_cpu_context *cpuctx,
2712 enum event_type_t event_type,
2713 struct task_struct *task);
2715 static void task_ctx_sched_out(struct perf_cpu_context *cpuctx,
2716 struct perf_event_context *ctx,
2717 enum event_type_t event_type)
2719 if (!cpuctx->task_ctx)
2722 if (WARN_ON_ONCE(ctx != cpuctx->task_ctx))
2725 ctx_sched_out(ctx, cpuctx, event_type);
2728 static void perf_event_sched_in(struct perf_cpu_context *cpuctx,
2729 struct perf_event_context *ctx,
2730 struct task_struct *task)
2732 cpu_ctx_sched_in(cpuctx, EVENT_PINNED, task);
2734 ctx_sched_in(ctx, cpuctx, EVENT_PINNED, task);
2735 cpu_ctx_sched_in(cpuctx, EVENT_FLEXIBLE, task);
2737 ctx_sched_in(ctx, cpuctx, EVENT_FLEXIBLE, task);
2741 * We want to maintain the following priority of scheduling:
2742 * - CPU pinned (EVENT_CPU | EVENT_PINNED)
2743 * - task pinned (EVENT_PINNED)
2744 * - CPU flexible (EVENT_CPU | EVENT_FLEXIBLE)
2745 * - task flexible (EVENT_FLEXIBLE).
2747 * In order to avoid unscheduling and scheduling back in everything every
2748 * time an event is added, only do it for the groups of equal priority and
2751 * This can be called after a batch operation on task events, in which case
2752 * event_type is a bit mask of the types of events involved. For CPU events,
2753 * event_type is only either EVENT_PINNED or EVENT_FLEXIBLE.
2755 static void ctx_resched(struct perf_cpu_context *cpuctx,
2756 struct perf_event_context *task_ctx,
2757 enum event_type_t event_type)
2759 enum event_type_t ctx_event_type;
2760 bool cpu_event = !!(event_type & EVENT_CPU);
2763 * If pinned groups are involved, flexible groups also need to be
2766 if (event_type & EVENT_PINNED)
2767 event_type |= EVENT_FLEXIBLE;
2769 ctx_event_type = event_type & EVENT_ALL;
2771 perf_pmu_disable(cpuctx->ctx.pmu);
2773 task_ctx_sched_out(cpuctx, task_ctx, event_type);
2776 * Decide which cpu ctx groups to schedule out based on the types
2777 * of events that caused rescheduling:
2778 * - EVENT_CPU: schedule out corresponding groups;
2779 * - EVENT_PINNED task events: schedule out EVENT_FLEXIBLE groups;
2780 * - otherwise, do nothing more.
2783 cpu_ctx_sched_out(cpuctx, ctx_event_type);
2784 else if (ctx_event_type & EVENT_PINNED)
2785 cpu_ctx_sched_out(cpuctx, EVENT_FLEXIBLE);
2787 perf_event_sched_in(cpuctx, task_ctx, current);
2788 perf_pmu_enable(cpuctx->ctx.pmu);
2791 void perf_pmu_resched(struct pmu *pmu)
2793 struct perf_cpu_context *cpuctx = this_cpu_ptr(pmu->pmu_cpu_context);
2794 struct perf_event_context *task_ctx = cpuctx->task_ctx;
2796 perf_ctx_lock(cpuctx, task_ctx);
2797 ctx_resched(cpuctx, task_ctx, EVENT_ALL|EVENT_CPU);
2798 perf_ctx_unlock(cpuctx, task_ctx);
2802 * Cross CPU call to install and enable a performance event
2804 * Very similar to remote_function() + event_function() but cannot assume that
2805 * things like ctx->is_active and cpuctx->task_ctx are set.
2807 static int __perf_install_in_context(void *info)
2809 struct perf_event *event = info;
2810 struct perf_event_context *ctx = event->ctx;
2811 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
2812 struct perf_event_context *task_ctx = cpuctx->task_ctx;
2813 bool reprogram = true;
2816 raw_spin_lock(&cpuctx->ctx.lock);
2818 raw_spin_lock(&ctx->lock);
2821 reprogram = (ctx->task == current);
2824 * If the task is running, it must be running on this CPU,
2825 * otherwise we cannot reprogram things.
2827 * If its not running, we don't care, ctx->lock will
2828 * serialize against it becoming runnable.
2830 if (task_curr(ctx->task) && !reprogram) {
2835 WARN_ON_ONCE(reprogram && cpuctx->task_ctx && cpuctx->task_ctx != ctx);
2836 } else if (task_ctx) {
2837 raw_spin_lock(&task_ctx->lock);
2840 #ifdef CONFIG_CGROUP_PERF
2841 if (event->state > PERF_EVENT_STATE_OFF && is_cgroup_event(event)) {
2843 * If the current cgroup doesn't match the event's
2844 * cgroup, we should not try to schedule it.
2846 struct perf_cgroup *cgrp = perf_cgroup_from_task(current, ctx);
2847 reprogram = cgroup_is_descendant(cgrp->css.cgroup,
2848 event->cgrp->css.cgroup);
2853 ctx_sched_out(ctx, cpuctx, EVENT_TIME);
2854 add_event_to_ctx(event, ctx);
2855 ctx_resched(cpuctx, task_ctx, get_event_type(event));
2857 add_event_to_ctx(event, ctx);
2861 perf_ctx_unlock(cpuctx, task_ctx);
2866 static bool exclusive_event_installable(struct perf_event *event,
2867 struct perf_event_context *ctx);
2870 * Attach a performance event to a context.
2872 * Very similar to event_function_call, see comment there.
2875 perf_install_in_context(struct perf_event_context *ctx,
2876 struct perf_event *event,
2879 struct task_struct *task = READ_ONCE(ctx->task);
2881 lockdep_assert_held(&ctx->mutex);
2883 WARN_ON_ONCE(!exclusive_event_installable(event, ctx));
2885 if (event->cpu != -1)
2889 * Ensures that if we can observe event->ctx, both the event and ctx
2890 * will be 'complete'. See perf_iterate_sb_cpu().
2892 smp_store_release(&event->ctx, ctx);
2895 * perf_event_attr::disabled events will not run and can be initialized
2896 * without IPI. Except when this is the first event for the context, in
2897 * that case we need the magic of the IPI to set ctx->is_active.
2899 * The IOC_ENABLE that is sure to follow the creation of a disabled
2900 * event will issue the IPI and reprogram the hardware.
2902 if (__perf_effective_state(event) == PERF_EVENT_STATE_OFF && ctx->nr_events) {
2903 raw_spin_lock_irq(&ctx->lock);
2904 if (ctx->task == TASK_TOMBSTONE) {
2905 raw_spin_unlock_irq(&ctx->lock);
2908 add_event_to_ctx(event, ctx);
2909 raw_spin_unlock_irq(&ctx->lock);
2914 cpu_function_call(cpu, __perf_install_in_context, event);
2919 * Should not happen, we validate the ctx is still alive before calling.
2921 if (WARN_ON_ONCE(task == TASK_TOMBSTONE))
2925 * Installing events is tricky because we cannot rely on ctx->is_active
2926 * to be set in case this is the nr_events 0 -> 1 transition.
2928 * Instead we use task_curr(), which tells us if the task is running.
2929 * However, since we use task_curr() outside of rq::lock, we can race
2930 * against the actual state. This means the result can be wrong.
2932 * If we get a false positive, we retry, this is harmless.
2934 * If we get a false negative, things are complicated. If we are after
2935 * perf_event_context_sched_in() ctx::lock will serialize us, and the
2936 * value must be correct. If we're before, it doesn't matter since
2937 * perf_event_context_sched_in() will program the counter.
2939 * However, this hinges on the remote context switch having observed
2940 * our task->perf_event_ctxp[] store, such that it will in fact take
2941 * ctx::lock in perf_event_context_sched_in().
2943 * We do this by task_function_call(), if the IPI fails to hit the task
2944 * we know any future context switch of task must see the
2945 * perf_event_ctpx[] store.
2949 * This smp_mb() orders the task->perf_event_ctxp[] store with the
2950 * task_cpu() load, such that if the IPI then does not find the task
2951 * running, a future context switch of that task must observe the
2956 if (!task_function_call(task, __perf_install_in_context, event))
2959 raw_spin_lock_irq(&ctx->lock);
2961 if (WARN_ON_ONCE(task == TASK_TOMBSTONE)) {
2963 * Cannot happen because we already checked above (which also
2964 * cannot happen), and we hold ctx->mutex, which serializes us
2965 * against perf_event_exit_task_context().
2967 raw_spin_unlock_irq(&ctx->lock);
2971 * If the task is not running, ctx->lock will avoid it becoming so,
2972 * thus we can safely install the event.
2974 if (task_curr(task)) {
2975 raw_spin_unlock_irq(&ctx->lock);
2978 add_event_to_ctx(event, ctx);
2979 raw_spin_unlock_irq(&ctx->lock);
2983 * Cross CPU call to enable a performance event
2985 static void __perf_event_enable(struct perf_event *event,
2986 struct perf_cpu_context *cpuctx,
2987 struct perf_event_context *ctx,
2990 struct perf_event *leader = event->group_leader;
2991 struct perf_event_context *task_ctx;
2993 if (event->state >= PERF_EVENT_STATE_INACTIVE ||
2994 event->state <= PERF_EVENT_STATE_ERROR)
2998 ctx_sched_out(ctx, cpuctx, EVENT_TIME);
3000 perf_event_set_state(event, PERF_EVENT_STATE_INACTIVE);
3001 perf_cgroup_event_enable(event, ctx);
3003 if (!ctx->is_active)
3006 if (!event_filter_match(event)) {
3007 ctx_sched_in(ctx, cpuctx, EVENT_TIME, current);
3012 * If the event is in a group and isn't the group leader,
3013 * then don't put it on unless the group is on.
3015 if (leader != event && leader->state != PERF_EVENT_STATE_ACTIVE) {
3016 ctx_sched_in(ctx, cpuctx, EVENT_TIME, current);
3020 task_ctx = cpuctx->task_ctx;
3022 WARN_ON_ONCE(task_ctx != ctx);
3024 ctx_resched(cpuctx, task_ctx, get_event_type(event));
3030 * If event->ctx is a cloned context, callers must make sure that
3031 * every task struct that event->ctx->task could possibly point to
3032 * remains valid. This condition is satisfied when called through
3033 * perf_event_for_each_child or perf_event_for_each as described
3034 * for perf_event_disable.
3036 static void _perf_event_enable(struct perf_event *event)
3038 struct perf_event_context *ctx = event->ctx;
3040 raw_spin_lock_irq(&ctx->lock);
3041 if (event->state >= PERF_EVENT_STATE_INACTIVE ||
3042 event->state < PERF_EVENT_STATE_ERROR) {
3044 raw_spin_unlock_irq(&ctx->lock);
3049 * If the event is in error state, clear that first.
3051 * That way, if we see the event in error state below, we know that it
3052 * has gone back into error state, as distinct from the task having
3053 * been scheduled away before the cross-call arrived.
3055 if (event->state == PERF_EVENT_STATE_ERROR) {
3057 * Detached SIBLING events cannot leave ERROR state.
3059 if (event->event_caps & PERF_EV_CAP_SIBLING &&
3060 event->group_leader == event)
3063 event->state = PERF_EVENT_STATE_OFF;
3065 raw_spin_unlock_irq(&ctx->lock);
3067 event_function_call(event, __perf_event_enable, NULL);
3071 * See perf_event_disable();
3073 void perf_event_enable(struct perf_event *event)
3075 struct perf_event_context *ctx;
3077 ctx = perf_event_ctx_lock(event);
3078 _perf_event_enable(event);
3079 perf_event_ctx_unlock(event, ctx);
3081 EXPORT_SYMBOL_GPL(perf_event_enable);
3083 struct stop_event_data {
3084 struct perf_event *event;
3085 unsigned int restart;
3088 static int __perf_event_stop(void *info)
3090 struct stop_event_data *sd = info;
3091 struct perf_event *event = sd->event;
3093 /* if it's already INACTIVE, do nothing */
3094 if (READ_ONCE(event->state) != PERF_EVENT_STATE_ACTIVE)
3097 /* matches smp_wmb() in event_sched_in() */
3101 * There is a window with interrupts enabled before we get here,
3102 * so we need to check again lest we try to stop another CPU's event.
3104 if (READ_ONCE(event->oncpu) != smp_processor_id())
3107 event->pmu->stop(event, PERF_EF_UPDATE);
3110 * May race with the actual stop (through perf_pmu_output_stop()),
3111 * but it is only used for events with AUX ring buffer, and such
3112 * events will refuse to restart because of rb::aux_mmap_count==0,
3113 * see comments in perf_aux_output_begin().
3115 * Since this is happening on an event-local CPU, no trace is lost
3119 event->pmu->start(event, 0);
3124 static int perf_event_stop(struct perf_event *event, int restart)
3126 struct stop_event_data sd = {
3133 if (READ_ONCE(event->state) != PERF_EVENT_STATE_ACTIVE)
3136 /* matches smp_wmb() in event_sched_in() */
3140 * We only want to restart ACTIVE events, so if the event goes
3141 * inactive here (event->oncpu==-1), there's nothing more to do;
3142 * fall through with ret==-ENXIO.
3144 ret = cpu_function_call(READ_ONCE(event->oncpu),
3145 __perf_event_stop, &sd);
3146 } while (ret == -EAGAIN);
3152 * In order to contain the amount of racy and tricky in the address filter
3153 * configuration management, it is a two part process:
3155 * (p1) when userspace mappings change as a result of (1) or (2) or (3) below,
3156 * we update the addresses of corresponding vmas in
3157 * event::addr_filter_ranges array and bump the event::addr_filters_gen;
3158 * (p2) when an event is scheduled in (pmu::add), it calls
3159 * perf_event_addr_filters_sync() which calls pmu::addr_filters_sync()
3160 * if the generation has changed since the previous call.
3162 * If (p1) happens while the event is active, we restart it to force (p2).
3164 * (1) perf_addr_filters_apply(): adjusting filters' offsets based on
3165 * pre-existing mappings, called once when new filters arrive via SET_FILTER
3167 * (2) perf_addr_filters_adjust(): adjusting filters' offsets based on newly
3168 * registered mapping, called for every new mmap(), with mm::mmap_lock down
3170 * (3) perf_event_addr_filters_exec(): clearing filters' offsets in the process
3173 void perf_event_addr_filters_sync(struct perf_event *event)
3175 struct perf_addr_filters_head *ifh = perf_event_addr_filters(event);
3177 if (!has_addr_filter(event))
3180 raw_spin_lock(&ifh->lock);
3181 if (event->addr_filters_gen != event->hw.addr_filters_gen) {
3182 event->pmu->addr_filters_sync(event);
3183 event->hw.addr_filters_gen = event->addr_filters_gen;
3185 raw_spin_unlock(&ifh->lock);
3187 EXPORT_SYMBOL_GPL(perf_event_addr_filters_sync);
3189 static int _perf_event_refresh(struct perf_event *event, int refresh)
3192 * not supported on inherited events
3194 if (event->attr.inherit || !is_sampling_event(event))
3197 atomic_add(refresh, &event->event_limit);
3198 _perf_event_enable(event);
3204 * See perf_event_disable()
3206 int perf_event_refresh(struct perf_event *event, int refresh)
3208 struct perf_event_context *ctx;
3211 ctx = perf_event_ctx_lock(event);
3212 ret = _perf_event_refresh(event, refresh);
3213 perf_event_ctx_unlock(event, ctx);
3217 EXPORT_SYMBOL_GPL(perf_event_refresh);
3219 static int perf_event_modify_breakpoint(struct perf_event *bp,
3220 struct perf_event_attr *attr)
3224 _perf_event_disable(bp);
3226 err = modify_user_hw_breakpoint_check(bp, attr, true);
3228 if (!bp->attr.disabled)
3229 _perf_event_enable(bp);
3234 static int perf_event_modify_attr(struct perf_event *event,
3235 struct perf_event_attr *attr)
3237 int (*func)(struct perf_event *, struct perf_event_attr *);
3238 struct perf_event *child;
3241 if (event->attr.type != attr->type)
3244 switch (event->attr.type) {
3245 case PERF_TYPE_BREAKPOINT:
3246 func = perf_event_modify_breakpoint;
3249 /* Place holder for future additions. */
3253 WARN_ON_ONCE(event->ctx->parent_ctx);
3255 mutex_lock(&event->child_mutex);
3256 err = func(event, attr);
3259 list_for_each_entry(child, &event->child_list, child_list) {
3260 err = func(child, attr);
3265 mutex_unlock(&event->child_mutex);
3269 static void ctx_sched_out(struct perf_event_context *ctx,
3270 struct perf_cpu_context *cpuctx,
3271 enum event_type_t event_type)
3273 struct perf_event *event, *tmp;
3274 int is_active = ctx->is_active;
3276 lockdep_assert_held(&ctx->lock);
3278 if (likely(!ctx->nr_events)) {
3280 * See __perf_remove_from_context().
3282 WARN_ON_ONCE(ctx->is_active);
3284 WARN_ON_ONCE(cpuctx->task_ctx);
3289 * Always update time if it was set; not only when it changes.
3290 * Otherwise we can 'forget' to update time for any but the last
3291 * context we sched out. For example:
3293 * ctx_sched_out(.event_type = EVENT_FLEXIBLE)
3294 * ctx_sched_out(.event_type = EVENT_PINNED)
3296 * would only update time for the pinned events.
3298 if (is_active & EVENT_TIME) {
3299 /* update (and stop) ctx time */
3300 update_context_time(ctx);
3301 update_cgrp_time_from_cpuctx(cpuctx, ctx == &cpuctx->ctx);
3303 * CPU-release for the below ->is_active store,
3304 * see __load_acquire() in perf_event_time_now()
3309 ctx->is_active &= ~event_type;
3310 if (!(ctx->is_active & EVENT_ALL))
3314 WARN_ON_ONCE(cpuctx->task_ctx != ctx);
3315 if (!ctx->is_active)
3316 cpuctx->task_ctx = NULL;
3319 is_active ^= ctx->is_active; /* changed bits */
3321 if (!ctx->nr_active || !(is_active & EVENT_ALL))
3324 perf_pmu_disable(ctx->pmu);
3325 if (is_active & EVENT_PINNED) {
3326 list_for_each_entry_safe(event, tmp, &ctx->pinned_active, active_list)
3327 group_sched_out(event, cpuctx, ctx);
3330 if (is_active & EVENT_FLEXIBLE) {
3331 list_for_each_entry_safe(event, tmp, &ctx->flexible_active, active_list)
3332 group_sched_out(event, cpuctx, ctx);
3335 * Since we cleared EVENT_FLEXIBLE, also clear
3336 * rotate_necessary, is will be reset by
3337 * ctx_flexible_sched_in() when needed.
3339 ctx->rotate_necessary = 0;
3341 perf_pmu_enable(ctx->pmu);
3345 * Test whether two contexts are equivalent, i.e. whether they have both been
3346 * cloned from the same version of the same context.
3348 * Equivalence is measured using a generation number in the context that is
3349 * incremented on each modification to it; see unclone_ctx(), list_add_event()
3350 * and list_del_event().
3352 static int context_equiv(struct perf_event_context *ctx1,
3353 struct perf_event_context *ctx2)
3355 lockdep_assert_held(&ctx1->lock);
3356 lockdep_assert_held(&ctx2->lock);
3358 /* Pinning disables the swap optimization */
3359 if (ctx1->pin_count || ctx2->pin_count)
3362 /* If ctx1 is the parent of ctx2 */
3363 if (ctx1 == ctx2->parent_ctx && ctx1->generation == ctx2->parent_gen)
3366 /* If ctx2 is the parent of ctx1 */
3367 if (ctx1->parent_ctx == ctx2 && ctx1->parent_gen == ctx2->generation)
3371 * If ctx1 and ctx2 have the same parent; we flatten the parent
3372 * hierarchy, see perf_event_init_context().
3374 if (ctx1->parent_ctx && ctx1->parent_ctx == ctx2->parent_ctx &&
3375 ctx1->parent_gen == ctx2->parent_gen)
3382 static void __perf_event_sync_stat(struct perf_event *event,
3383 struct perf_event *next_event)
3387 if (!event->attr.inherit_stat)
3391 * Update the event value, we cannot use perf_event_read()
3392 * because we're in the middle of a context switch and have IRQs
3393 * disabled, which upsets smp_call_function_single(), however
3394 * we know the event must be on the current CPU, therefore we
3395 * don't need to use it.
3397 if (event->state == PERF_EVENT_STATE_ACTIVE)
3398 event->pmu->read(event);
3400 perf_event_update_time(event);
3403 * In order to keep per-task stats reliable we need to flip the event
3404 * values when we flip the contexts.
3406 value = local64_read(&next_event->count);
3407 value = local64_xchg(&event->count, value);
3408 local64_set(&next_event->count, value);
3410 swap(event->total_time_enabled, next_event->total_time_enabled);
3411 swap(event->total_time_running, next_event->total_time_running);
3414 * Since we swizzled the values, update the user visible data too.
3416 perf_event_update_userpage(event);
3417 perf_event_update_userpage(next_event);
3420 static void perf_event_sync_stat(struct perf_event_context *ctx,
3421 struct perf_event_context *next_ctx)
3423 struct perf_event *event, *next_event;
3428 update_context_time(ctx);
3430 event = list_first_entry(&ctx->event_list,
3431 struct perf_event, event_entry);
3433 next_event = list_first_entry(&next_ctx->event_list,
3434 struct perf_event, event_entry);
3436 while (&event->event_entry != &ctx->event_list &&
3437 &next_event->event_entry != &next_ctx->event_list) {
3439 __perf_event_sync_stat(event, next_event);
3441 event = list_next_entry(event, event_entry);
3442 next_event = list_next_entry(next_event, event_entry);
3446 static void perf_event_context_sched_out(struct task_struct *task, int ctxn,
3447 struct task_struct *next)
3449 struct perf_event_context *ctx = task->perf_event_ctxp[ctxn];
3450 struct perf_event_context *next_ctx;
3451 struct perf_event_context *parent, *next_parent;
3452 struct perf_cpu_context *cpuctx;
3460 cpuctx = __get_cpu_context(ctx);
3461 if (!cpuctx->task_ctx)
3465 next_ctx = next->perf_event_ctxp[ctxn];
3469 parent = rcu_dereference(ctx->parent_ctx);
3470 next_parent = rcu_dereference(next_ctx->parent_ctx);
3472 /* If neither context have a parent context; they cannot be clones. */
3473 if (!parent && !next_parent)
3476 if (next_parent == ctx || next_ctx == parent || next_parent == parent) {
3478 * Looks like the two contexts are clones, so we might be
3479 * able to optimize the context switch. We lock both
3480 * contexts and check that they are clones under the
3481 * lock (including re-checking that neither has been
3482 * uncloned in the meantime). It doesn't matter which
3483 * order we take the locks because no other cpu could
3484 * be trying to lock both of these tasks.
3486 raw_spin_lock(&ctx->lock);
3487 raw_spin_lock_nested(&next_ctx->lock, SINGLE_DEPTH_NESTING);
3488 if (context_equiv(ctx, next_ctx)) {
3490 WRITE_ONCE(ctx->task, next);
3491 WRITE_ONCE(next_ctx->task, task);
3493 perf_pmu_disable(pmu);
3495 if (cpuctx->sched_cb_usage && pmu->sched_task)
3496 pmu->sched_task(ctx, false);
3499 * PMU specific parts of task perf context can require
3500 * additional synchronization. As an example of such
3501 * synchronization see implementation details of Intel
3502 * LBR call stack data profiling;
3504 if (pmu->swap_task_ctx)
3505 pmu->swap_task_ctx(ctx, next_ctx);
3507 swap(ctx->task_ctx_data, next_ctx->task_ctx_data);
3509 perf_pmu_enable(pmu);
3512 * RCU_INIT_POINTER here is safe because we've not
3513 * modified the ctx and the above modification of
3514 * ctx->task and ctx->task_ctx_data are immaterial
3515 * since those values are always verified under
3516 * ctx->lock which we're now holding.
3518 RCU_INIT_POINTER(task->perf_event_ctxp[ctxn], next_ctx);
3519 RCU_INIT_POINTER(next->perf_event_ctxp[ctxn], ctx);
3523 perf_event_sync_stat(ctx, next_ctx);
3525 raw_spin_unlock(&next_ctx->lock);
3526 raw_spin_unlock(&ctx->lock);
3532 raw_spin_lock(&ctx->lock);
3533 perf_pmu_disable(pmu);
3535 if (cpuctx->sched_cb_usage && pmu->sched_task)
3536 pmu->sched_task(ctx, false);
3537 task_ctx_sched_out(cpuctx, ctx, EVENT_ALL);
3539 perf_pmu_enable(pmu);
3540 raw_spin_unlock(&ctx->lock);
3544 static DEFINE_PER_CPU(struct list_head, sched_cb_list);
3546 void perf_sched_cb_dec(struct pmu *pmu)
3548 struct perf_cpu_context *cpuctx = this_cpu_ptr(pmu->pmu_cpu_context);
3550 this_cpu_dec(perf_sched_cb_usages);
3552 if (!--cpuctx->sched_cb_usage)
3553 list_del(&cpuctx->sched_cb_entry);
3557 void perf_sched_cb_inc(struct pmu *pmu)
3559 struct perf_cpu_context *cpuctx = this_cpu_ptr(pmu->pmu_cpu_context);
3561 if (!cpuctx->sched_cb_usage++)
3562 list_add(&cpuctx->sched_cb_entry, this_cpu_ptr(&sched_cb_list));
3564 this_cpu_inc(perf_sched_cb_usages);
3568 * This function provides the context switch callback to the lower code
3569 * layer. It is invoked ONLY when the context switch callback is enabled.
3571 * This callback is relevant even to per-cpu events; for example multi event
3572 * PEBS requires this to provide PID/TID information. This requires we flush
3573 * all queued PEBS records before we context switch to a new task.
3575 static void __perf_pmu_sched_task(struct perf_cpu_context *cpuctx, bool sched_in)
3579 pmu = cpuctx->ctx.pmu; /* software PMUs will not have sched_task */
3581 if (WARN_ON_ONCE(!pmu->sched_task))
3584 perf_ctx_lock(cpuctx, cpuctx->task_ctx);
3585 perf_pmu_disable(pmu);
3587 pmu->sched_task(cpuctx->task_ctx, sched_in);
3589 perf_pmu_enable(pmu);
3590 perf_ctx_unlock(cpuctx, cpuctx->task_ctx);
3593 static void perf_pmu_sched_task(struct task_struct *prev,
3594 struct task_struct *next,
3597 struct perf_cpu_context *cpuctx;
3602 list_for_each_entry(cpuctx, this_cpu_ptr(&sched_cb_list), sched_cb_entry) {
3603 /* will be handled in perf_event_context_sched_in/out */
3604 if (cpuctx->task_ctx)
3607 __perf_pmu_sched_task(cpuctx, sched_in);
3611 static void perf_event_switch(struct task_struct *task,
3612 struct task_struct *next_prev, bool sched_in);
3614 #define for_each_task_context_nr(ctxn) \
3615 for ((ctxn) = 0; (ctxn) < perf_nr_task_contexts; (ctxn)++)
3618 * Called from scheduler to remove the events of the current task,
3619 * with interrupts disabled.
3621 * We stop each event and update the event value in event->count.
3623 * This does not protect us against NMI, but disable()
3624 * sets the disabled bit in the control field of event _before_
3625 * accessing the event control register. If a NMI hits, then it will
3626 * not restart the event.
3628 void __perf_event_task_sched_out(struct task_struct *task,
3629 struct task_struct *next)
3633 if (__this_cpu_read(perf_sched_cb_usages))
3634 perf_pmu_sched_task(task, next, false);
3636 if (atomic_read(&nr_switch_events))
3637 perf_event_switch(task, next, false);
3639 for_each_task_context_nr(ctxn)
3640 perf_event_context_sched_out(task, ctxn, next);
3643 * if cgroup events exist on this CPU, then we need
3644 * to check if we have to switch out PMU state.
3645 * cgroup event are system-wide mode only
3647 if (atomic_read(this_cpu_ptr(&perf_cgroup_events)))
3648 perf_cgroup_sched_out(task, next);
3652 * Called with IRQs disabled
3654 static void cpu_ctx_sched_out(struct perf_cpu_context *cpuctx,
3655 enum event_type_t event_type)
3657 ctx_sched_out(&cpuctx->ctx, cpuctx, event_type);
3660 static bool perf_less_group_idx(const void *l, const void *r)
3662 const struct perf_event *le = *(const struct perf_event **)l;
3663 const struct perf_event *re = *(const struct perf_event **)r;
3665 return le->group_index < re->group_index;
3668 static void swap_ptr(void *l, void *r)
3670 void **lp = l, **rp = r;
3675 static const struct min_heap_callbacks perf_min_heap = {
3676 .elem_size = sizeof(struct perf_event *),
3677 .less = perf_less_group_idx,
3681 static void __heap_add(struct min_heap *heap, struct perf_event *event)
3683 struct perf_event **itrs = heap->data;
3686 itrs[heap->nr] = event;
3691 static noinline int visit_groups_merge(struct perf_cpu_context *cpuctx,
3692 struct perf_event_groups *groups, int cpu,
3693 int (*func)(struct perf_event *, void *),
3696 #ifdef CONFIG_CGROUP_PERF
3697 struct cgroup_subsys_state *css = NULL;
3699 /* Space for per CPU and/or any CPU event iterators. */
3700 struct perf_event *itrs[2];
3701 struct min_heap event_heap;
3702 struct perf_event **evt;
3706 event_heap = (struct min_heap){
3707 .data = cpuctx->heap,
3709 .size = cpuctx->heap_size,
3712 lockdep_assert_held(&cpuctx->ctx.lock);
3714 #ifdef CONFIG_CGROUP_PERF
3716 css = &cpuctx->cgrp->css;
3719 event_heap = (struct min_heap){
3722 .size = ARRAY_SIZE(itrs),
3724 /* Events not within a CPU context may be on any CPU. */
3725 __heap_add(&event_heap, perf_event_groups_first(groups, -1, NULL));
3727 evt = event_heap.data;
3729 __heap_add(&event_heap, perf_event_groups_first(groups, cpu, NULL));
3731 #ifdef CONFIG_CGROUP_PERF
3732 for (; css; css = css->parent)
3733 __heap_add(&event_heap, perf_event_groups_first(groups, cpu, css->cgroup));
3736 min_heapify_all(&event_heap, &perf_min_heap);
3738 while (event_heap.nr) {
3739 ret = func(*evt, data);
3743 *evt = perf_event_groups_next(*evt);
3745 min_heapify(&event_heap, 0, &perf_min_heap);
3747 min_heap_pop(&event_heap, &perf_min_heap);
3754 * Because the userpage is strictly per-event (there is no concept of context,
3755 * so there cannot be a context indirection), every userpage must be updated
3756 * when context time starts :-(
3758 * IOW, we must not miss EVENT_TIME edges.
3760 static inline bool event_update_userpage(struct perf_event *event)
3762 if (likely(!atomic_read(&event->mmap_count)))
3765 perf_event_update_time(event);
3766 perf_event_update_userpage(event);
3771 static inline void group_update_userpage(struct perf_event *group_event)
3773 struct perf_event *event;
3775 if (!event_update_userpage(group_event))
3778 for_each_sibling_event(event, group_event)
3779 event_update_userpage(event);
3782 static int merge_sched_in(struct perf_event *event, void *data)
3784 struct perf_event_context *ctx = event->ctx;
3785 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
3786 int *can_add_hw = data;
3788 if (event->state <= PERF_EVENT_STATE_OFF)
3791 if (!event_filter_match(event))
3794 if (group_can_go_on(event, cpuctx, *can_add_hw)) {
3795 if (!group_sched_in(event, cpuctx, ctx))
3796 list_add_tail(&event->active_list, get_event_list(event));
3799 if (event->state == PERF_EVENT_STATE_INACTIVE) {
3801 if (event->attr.pinned) {
3802 perf_cgroup_event_disable(event, ctx);
3803 perf_event_set_state(event, PERF_EVENT_STATE_ERROR);
3805 ctx->rotate_necessary = 1;
3806 perf_mux_hrtimer_restart(cpuctx);
3807 group_update_userpage(event);
3815 ctx_pinned_sched_in(struct perf_event_context *ctx,
3816 struct perf_cpu_context *cpuctx)
3820 if (ctx != &cpuctx->ctx)
3823 visit_groups_merge(cpuctx, &ctx->pinned_groups,
3825 merge_sched_in, &can_add_hw);
3829 ctx_flexible_sched_in(struct perf_event_context *ctx,
3830 struct perf_cpu_context *cpuctx)
3834 if (ctx != &cpuctx->ctx)
3837 visit_groups_merge(cpuctx, &ctx->flexible_groups,
3839 merge_sched_in, &can_add_hw);
3843 ctx_sched_in(struct perf_event_context *ctx,
3844 struct perf_cpu_context *cpuctx,
3845 enum event_type_t event_type,
3846 struct task_struct *task)
3848 int is_active = ctx->is_active;
3850 lockdep_assert_held(&ctx->lock);
3852 if (likely(!ctx->nr_events))
3855 if (is_active ^ EVENT_TIME) {
3856 /* start ctx time */
3857 __update_context_time(ctx, false);
3858 perf_cgroup_set_timestamp(task, ctx);
3860 * CPU-release for the below ->is_active store,
3861 * see __load_acquire() in perf_event_time_now()
3866 ctx->is_active |= (event_type | EVENT_TIME);
3869 cpuctx->task_ctx = ctx;
3871 WARN_ON_ONCE(cpuctx->task_ctx != ctx);
3874 is_active ^= ctx->is_active; /* changed bits */
3877 * First go through the list and put on any pinned groups
3878 * in order to give them the best chance of going on.
3880 if (is_active & EVENT_PINNED)
3881 ctx_pinned_sched_in(ctx, cpuctx);
3883 /* Then walk through the lower prio flexible groups */
3884 if (is_active & EVENT_FLEXIBLE)
3885 ctx_flexible_sched_in(ctx, cpuctx);
3888 static void cpu_ctx_sched_in(struct perf_cpu_context *cpuctx,
3889 enum event_type_t event_type,
3890 struct task_struct *task)
3892 struct perf_event_context *ctx = &cpuctx->ctx;
3894 ctx_sched_in(ctx, cpuctx, event_type, task);
3897 static void perf_event_context_sched_in(struct perf_event_context *ctx,
3898 struct task_struct *task)
3900 struct perf_cpu_context *cpuctx;
3903 cpuctx = __get_cpu_context(ctx);
3906 * HACK: for HETEROGENEOUS the task context might have switched to a
3907 * different PMU, force (re)set the context,
3909 pmu = ctx->pmu = cpuctx->ctx.pmu;
3911 if (cpuctx->task_ctx == ctx) {
3912 if (cpuctx->sched_cb_usage)
3913 __perf_pmu_sched_task(cpuctx, true);
3917 perf_ctx_lock(cpuctx, ctx);
3919 * We must check ctx->nr_events while holding ctx->lock, such
3920 * that we serialize against perf_install_in_context().
3922 if (!ctx->nr_events)
3925 perf_pmu_disable(pmu);
3927 * We want to keep the following priority order:
3928 * cpu pinned (that don't need to move), task pinned,
3929 * cpu flexible, task flexible.
3931 * However, if task's ctx is not carrying any pinned
3932 * events, no need to flip the cpuctx's events around.
3934 if (!RB_EMPTY_ROOT(&ctx->pinned_groups.tree))
3935 cpu_ctx_sched_out(cpuctx, EVENT_FLEXIBLE);
3936 perf_event_sched_in(cpuctx, ctx, task);
3938 if (cpuctx->sched_cb_usage && pmu->sched_task)
3939 pmu->sched_task(cpuctx->task_ctx, true);
3941 perf_pmu_enable(pmu);
3944 perf_ctx_unlock(cpuctx, ctx);
3948 * Called from scheduler to add the events of the current task
3949 * with interrupts disabled.
3951 * We restore the event value and then enable it.
3953 * This does not protect us against NMI, but enable()
3954 * sets the enabled bit in the control field of event _before_
3955 * accessing the event control register. If a NMI hits, then it will
3956 * keep the event running.
3958 void __perf_event_task_sched_in(struct task_struct *prev,
3959 struct task_struct *task)
3961 struct perf_event_context *ctx;
3965 * If cgroup events exist on this CPU, then we need to check if we have
3966 * to switch in PMU state; cgroup event are system-wide mode only.
3968 * Since cgroup events are CPU events, we must schedule these in before
3969 * we schedule in the task events.
3971 if (atomic_read(this_cpu_ptr(&perf_cgroup_events)))
3972 perf_cgroup_sched_in(prev, task);
3974 for_each_task_context_nr(ctxn) {
3975 ctx = task->perf_event_ctxp[ctxn];
3979 perf_event_context_sched_in(ctx, task);
3982 if (atomic_read(&nr_switch_events))
3983 perf_event_switch(task, prev, true);
3985 if (__this_cpu_read(perf_sched_cb_usages))
3986 perf_pmu_sched_task(prev, task, true);
3989 static u64 perf_calculate_period(struct perf_event *event, u64 nsec, u64 count)
3991 u64 frequency = event->attr.sample_freq;
3992 u64 sec = NSEC_PER_SEC;
3993 u64 divisor, dividend;
3995 int count_fls, nsec_fls, frequency_fls, sec_fls;
3997 count_fls = fls64(count);
3998 nsec_fls = fls64(nsec);
3999 frequency_fls = fls64(frequency);
4003 * We got @count in @nsec, with a target of sample_freq HZ
4004 * the target period becomes:
4007 * period = -------------------
4008 * @nsec * sample_freq
4013 * Reduce accuracy by one bit such that @a and @b converge
4014 * to a similar magnitude.
4016 #define REDUCE_FLS(a, b) \
4018 if (a##_fls > b##_fls) { \
4028 * Reduce accuracy until either term fits in a u64, then proceed with
4029 * the other, so that finally we can do a u64/u64 division.
4031 while (count_fls + sec_fls > 64 && nsec_fls + frequency_fls > 64) {
4032 REDUCE_FLS(nsec, frequency);
4033 REDUCE_FLS(sec, count);
4036 if (count_fls + sec_fls > 64) {
4037 divisor = nsec * frequency;
4039 while (count_fls + sec_fls > 64) {
4040 REDUCE_FLS(count, sec);
4044 dividend = count * sec;
4046 dividend = count * sec;
4048 while (nsec_fls + frequency_fls > 64) {
4049 REDUCE_FLS(nsec, frequency);
4053 divisor = nsec * frequency;
4059 return div64_u64(dividend, divisor);
4062 static DEFINE_PER_CPU(int, perf_throttled_count);
4063 static DEFINE_PER_CPU(u64, perf_throttled_seq);
4065 static void perf_adjust_period(struct perf_event *event, u64 nsec, u64 count, bool disable)
4067 struct hw_perf_event *hwc = &event->hw;
4068 s64 period, sample_period;
4071 period = perf_calculate_period(event, nsec, count);
4073 delta = (s64)(period - hwc->sample_period);
4074 delta = (delta + 7) / 8; /* low pass filter */
4076 sample_period = hwc->sample_period + delta;
4081 hwc->sample_period = sample_period;
4083 if (local64_read(&hwc->period_left) > 8*sample_period) {
4085 event->pmu->stop(event, PERF_EF_UPDATE);
4087 local64_set(&hwc->period_left, 0);
4090 event->pmu->start(event, PERF_EF_RELOAD);
4095 * combine freq adjustment with unthrottling to avoid two passes over the
4096 * events. At the same time, make sure, having freq events does not change
4097 * the rate of unthrottling as that would introduce bias.
4099 static void perf_adjust_freq_unthr_context(struct perf_event_context *ctx,
4102 struct perf_event *event;
4103 struct hw_perf_event *hwc;
4104 u64 now, period = TICK_NSEC;
4108 * only need to iterate over all events iff:
4109 * - context have events in frequency mode (needs freq adjust)
4110 * - there are events to unthrottle on this cpu
4112 if (!(ctx->nr_freq || needs_unthr))
4115 raw_spin_lock(&ctx->lock);
4116 perf_pmu_disable(ctx->pmu);
4118 list_for_each_entry_rcu(event, &ctx->event_list, event_entry) {
4119 if (event->state != PERF_EVENT_STATE_ACTIVE)
4122 if (!event_filter_match(event))
4125 perf_pmu_disable(event->pmu);
4129 if (hwc->interrupts == MAX_INTERRUPTS) {
4130 hwc->interrupts = 0;
4131 perf_log_throttle(event, 1);
4132 event->pmu->start(event, 0);
4135 if (!event->attr.freq || !event->attr.sample_freq)
4139 * stop the event and update event->count
4141 event->pmu->stop(event, PERF_EF_UPDATE);
4143 now = local64_read(&event->count);
4144 delta = now - hwc->freq_count_stamp;
4145 hwc->freq_count_stamp = now;
4149 * reload only if value has changed
4150 * we have stopped the event so tell that
4151 * to perf_adjust_period() to avoid stopping it
4155 perf_adjust_period(event, period, delta, false);
4157 event->pmu->start(event, delta > 0 ? PERF_EF_RELOAD : 0);
4159 perf_pmu_enable(event->pmu);
4162 perf_pmu_enable(ctx->pmu);
4163 raw_spin_unlock(&ctx->lock);
4167 * Move @event to the tail of the @ctx's elegible events.
4169 static void rotate_ctx(struct perf_event_context *ctx, struct perf_event *event)
4172 * Rotate the first entry last of non-pinned groups. Rotation might be
4173 * disabled by the inheritance code.
4175 if (ctx->rotate_disable)
4178 perf_event_groups_delete(&ctx->flexible_groups, event);
4179 perf_event_groups_insert(&ctx->flexible_groups, event);
4182 /* pick an event from the flexible_groups to rotate */
4183 static inline struct perf_event *
4184 ctx_event_to_rotate(struct perf_event_context *ctx)
4186 struct perf_event *event;
4188 /* pick the first active flexible event */
4189 event = list_first_entry_or_null(&ctx->flexible_active,
4190 struct perf_event, active_list);
4192 /* if no active flexible event, pick the first event */
4194 event = rb_entry_safe(rb_first(&ctx->flexible_groups.tree),
4195 typeof(*event), group_node);
4199 * Unconditionally clear rotate_necessary; if ctx_flexible_sched_in()
4200 * finds there are unschedulable events, it will set it again.
4202 ctx->rotate_necessary = 0;
4207 static bool perf_rotate_context(struct perf_cpu_context *cpuctx)
4209 struct perf_event *cpu_event = NULL, *task_event = NULL;
4210 struct perf_event_context *task_ctx = NULL;
4211 int cpu_rotate, task_rotate;
4214 * Since we run this from IRQ context, nobody can install new
4215 * events, thus the event count values are stable.
4218 cpu_rotate = cpuctx->ctx.rotate_necessary;
4219 task_ctx = cpuctx->task_ctx;
4220 task_rotate = task_ctx ? task_ctx->rotate_necessary : 0;
4222 if (!(cpu_rotate || task_rotate))
4225 perf_ctx_lock(cpuctx, cpuctx->task_ctx);
4226 perf_pmu_disable(cpuctx->ctx.pmu);
4229 task_event = ctx_event_to_rotate(task_ctx);
4231 cpu_event = ctx_event_to_rotate(&cpuctx->ctx);
4234 * As per the order given at ctx_resched() first 'pop' task flexible
4235 * and then, if needed CPU flexible.
4237 if (task_event || (task_ctx && cpu_event))
4238 ctx_sched_out(task_ctx, cpuctx, EVENT_FLEXIBLE);
4240 cpu_ctx_sched_out(cpuctx, EVENT_FLEXIBLE);
4243 rotate_ctx(task_ctx, task_event);
4245 rotate_ctx(&cpuctx->ctx, cpu_event);
4247 perf_event_sched_in(cpuctx, task_ctx, current);
4249 perf_pmu_enable(cpuctx->ctx.pmu);
4250 perf_ctx_unlock(cpuctx, cpuctx->task_ctx);
4255 void perf_event_task_tick(void)
4257 struct list_head *head = this_cpu_ptr(&active_ctx_list);
4258 struct perf_event_context *ctx, *tmp;
4261 lockdep_assert_irqs_disabled();
4263 __this_cpu_inc(perf_throttled_seq);
4264 throttled = __this_cpu_xchg(perf_throttled_count, 0);
4265 tick_dep_clear_cpu(smp_processor_id(), TICK_DEP_BIT_PERF_EVENTS);
4267 list_for_each_entry_safe(ctx, tmp, head, active_ctx_list)
4268 perf_adjust_freq_unthr_context(ctx, throttled);
4271 static int event_enable_on_exec(struct perf_event *event,
4272 struct perf_event_context *ctx)
4274 if (!event->attr.enable_on_exec)
4277 event->attr.enable_on_exec = 0;
4278 if (event->state >= PERF_EVENT_STATE_INACTIVE)
4281 perf_event_set_state(event, PERF_EVENT_STATE_INACTIVE);
4287 * Enable all of a task's events that have been marked enable-on-exec.
4288 * This expects task == current.
4290 static void perf_event_enable_on_exec(int ctxn)
4292 struct perf_event_context *ctx, *clone_ctx = NULL;
4293 enum event_type_t event_type = 0;
4294 struct perf_cpu_context *cpuctx;
4295 struct perf_event *event;
4296 unsigned long flags;
4299 local_irq_save(flags);
4300 ctx = current->perf_event_ctxp[ctxn];
4301 if (!ctx || !ctx->nr_events)
4304 cpuctx = __get_cpu_context(ctx);
4305 perf_ctx_lock(cpuctx, ctx);
4306 ctx_sched_out(ctx, cpuctx, EVENT_TIME);
4307 list_for_each_entry(event, &ctx->event_list, event_entry) {
4308 enabled |= event_enable_on_exec(event, ctx);
4309 event_type |= get_event_type(event);
4313 * Unclone and reschedule this context if we enabled any event.
4316 clone_ctx = unclone_ctx(ctx);
4317 ctx_resched(cpuctx, ctx, event_type);
4319 ctx_sched_in(ctx, cpuctx, EVENT_TIME, current);
4321 perf_ctx_unlock(cpuctx, ctx);
4324 local_irq_restore(flags);
4330 static void perf_remove_from_owner(struct perf_event *event);
4331 static void perf_event_exit_event(struct perf_event *event,
4332 struct perf_event_context *ctx);
4335 * Removes all events from the current task that have been marked
4336 * remove-on-exec, and feeds their values back to parent events.
4338 static void perf_event_remove_on_exec(int ctxn)
4340 struct perf_event_context *ctx, *clone_ctx = NULL;
4341 struct perf_event *event, *next;
4342 LIST_HEAD(free_list);
4343 unsigned long flags;
4344 bool modified = false;
4346 ctx = perf_pin_task_context(current, ctxn);
4350 mutex_lock(&ctx->mutex);
4352 if (WARN_ON_ONCE(ctx->task != current))
4355 list_for_each_entry_safe(event, next, &ctx->event_list, event_entry) {
4356 if (!event->attr.remove_on_exec)
4359 if (!is_kernel_event(event))
4360 perf_remove_from_owner(event);
4364 perf_event_exit_event(event, ctx);
4367 raw_spin_lock_irqsave(&ctx->lock, flags);
4369 clone_ctx = unclone_ctx(ctx);
4371 raw_spin_unlock_irqrestore(&ctx->lock, flags);
4374 mutex_unlock(&ctx->mutex);
4381 struct perf_read_data {
4382 struct perf_event *event;
4387 static int __perf_event_read_cpu(struct perf_event *event, int event_cpu)
4389 u16 local_pkg, event_pkg;
4391 if (event->group_caps & PERF_EV_CAP_READ_ACTIVE_PKG) {
4392 int local_cpu = smp_processor_id();
4394 event_pkg = topology_physical_package_id(event_cpu);
4395 local_pkg = topology_physical_package_id(local_cpu);
4397 if (event_pkg == local_pkg)
4405 * Cross CPU call to read the hardware event
4407 static void __perf_event_read(void *info)
4409 struct perf_read_data *data = info;
4410 struct perf_event *sub, *event = data->event;
4411 struct perf_event_context *ctx = event->ctx;
4412 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
4413 struct pmu *pmu = event->pmu;
4416 * If this is a task context, we need to check whether it is
4417 * the current task context of this cpu. If not it has been
4418 * scheduled out before the smp call arrived. In that case
4419 * event->count would have been updated to a recent sample
4420 * when the event was scheduled out.
4422 if (ctx->task && cpuctx->task_ctx != ctx)
4425 raw_spin_lock(&ctx->lock);
4426 if (ctx->is_active & EVENT_TIME) {
4427 update_context_time(ctx);
4428 update_cgrp_time_from_event(event);
4431 perf_event_update_time(event);
4433 perf_event_update_sibling_time(event);
4435 if (event->state != PERF_EVENT_STATE_ACTIVE)
4444 pmu->start_txn(pmu, PERF_PMU_TXN_READ);
4448 for_each_sibling_event(sub, event) {
4449 if (sub->state == PERF_EVENT_STATE_ACTIVE) {
4451 * Use sibling's PMU rather than @event's since
4452 * sibling could be on different (eg: software) PMU.
4454 sub->pmu->read(sub);
4458 data->ret = pmu->commit_txn(pmu);
4461 raw_spin_unlock(&ctx->lock);
4464 static inline u64 perf_event_count(struct perf_event *event)
4466 return local64_read(&event->count) + atomic64_read(&event->child_count);
4469 static void calc_timer_values(struct perf_event *event,
4476 *now = perf_clock();
4477 ctx_time = perf_event_time_now(event, *now);
4478 __perf_update_times(event, ctx_time, enabled, running);
4482 * NMI-safe method to read a local event, that is an event that
4484 * - either for the current task, or for this CPU
4485 * - does not have inherit set, for inherited task events
4486 * will not be local and we cannot read them atomically
4487 * - must not have a pmu::count method
4489 int perf_event_read_local(struct perf_event *event, u64 *value,
4490 u64 *enabled, u64 *running)
4492 unsigned long flags;
4496 * Disabling interrupts avoids all counter scheduling (context
4497 * switches, timer based rotation and IPIs).
4499 local_irq_save(flags);
4502 * It must not be an event with inherit set, we cannot read
4503 * all child counters from atomic context.
4505 if (event->attr.inherit) {
4510 /* If this is a per-task event, it must be for current */
4511 if ((event->attach_state & PERF_ATTACH_TASK) &&
4512 event->hw.target != current) {
4517 /* If this is a per-CPU event, it must be for this CPU */
4518 if (!(event->attach_state & PERF_ATTACH_TASK) &&
4519 event->cpu != smp_processor_id()) {
4524 /* If this is a pinned event it must be running on this CPU */
4525 if (event->attr.pinned && event->oncpu != smp_processor_id()) {
4531 * If the event is currently on this CPU, its either a per-task event,
4532 * or local to this CPU. Furthermore it means its ACTIVE (otherwise
4535 if (event->oncpu == smp_processor_id())
4536 event->pmu->read(event);
4538 *value = local64_read(&event->count);
4539 if (enabled || running) {
4540 u64 __enabled, __running, __now;;
4542 calc_timer_values(event, &__now, &__enabled, &__running);
4544 *enabled = __enabled;
4546 *running = __running;
4549 local_irq_restore(flags);
4554 static int perf_event_read(struct perf_event *event, bool group)
4556 enum perf_event_state state = READ_ONCE(event->state);
4557 int event_cpu, ret = 0;
4560 * If event is enabled and currently active on a CPU, update the
4561 * value in the event structure:
4564 if (state == PERF_EVENT_STATE_ACTIVE) {
4565 struct perf_read_data data;
4568 * Orders the ->state and ->oncpu loads such that if we see
4569 * ACTIVE we must also see the right ->oncpu.
4571 * Matches the smp_wmb() from event_sched_in().
4575 event_cpu = READ_ONCE(event->oncpu);
4576 if ((unsigned)event_cpu >= nr_cpu_ids)
4579 data = (struct perf_read_data){
4586 event_cpu = __perf_event_read_cpu(event, event_cpu);
4589 * Purposely ignore the smp_call_function_single() return
4592 * If event_cpu isn't a valid CPU it means the event got
4593 * scheduled out and that will have updated the event count.
4595 * Therefore, either way, we'll have an up-to-date event count
4598 (void)smp_call_function_single(event_cpu, __perf_event_read, &data, 1);
4602 } else if (state == PERF_EVENT_STATE_INACTIVE) {
4603 struct perf_event_context *ctx = event->ctx;
4604 unsigned long flags;
4606 raw_spin_lock_irqsave(&ctx->lock, flags);
4607 state = event->state;
4608 if (state != PERF_EVENT_STATE_INACTIVE) {
4609 raw_spin_unlock_irqrestore(&ctx->lock, flags);
4614 * May read while context is not active (e.g., thread is
4615 * blocked), in that case we cannot update context time
4617 if (ctx->is_active & EVENT_TIME) {
4618 update_context_time(ctx);
4619 update_cgrp_time_from_event(event);
4622 perf_event_update_time(event);
4624 perf_event_update_sibling_time(event);
4625 raw_spin_unlock_irqrestore(&ctx->lock, flags);
4632 * Initialize the perf_event context in a task_struct:
4634 static void __perf_event_init_context(struct perf_event_context *ctx)
4636 raw_spin_lock_init(&ctx->lock);
4637 mutex_init(&ctx->mutex);
4638 INIT_LIST_HEAD(&ctx->active_ctx_list);
4639 perf_event_groups_init(&ctx->pinned_groups);
4640 perf_event_groups_init(&ctx->flexible_groups);
4641 INIT_LIST_HEAD(&ctx->event_list);
4642 INIT_LIST_HEAD(&ctx->pinned_active);
4643 INIT_LIST_HEAD(&ctx->flexible_active);
4644 refcount_set(&ctx->refcount, 1);
4647 static struct perf_event_context *
4648 alloc_perf_context(struct pmu *pmu, struct task_struct *task)
4650 struct perf_event_context *ctx;
4652 ctx = kzalloc(sizeof(struct perf_event_context), GFP_KERNEL);
4656 __perf_event_init_context(ctx);
4658 ctx->task = get_task_struct(task);
4664 static struct task_struct *
4665 find_lively_task_by_vpid(pid_t vpid)
4667 struct task_struct *task;
4673 task = find_task_by_vpid(vpid);
4675 get_task_struct(task);
4679 return ERR_PTR(-ESRCH);
4685 * Returns a matching context with refcount and pincount.
4687 static struct perf_event_context *
4688 find_get_context(struct pmu *pmu, struct task_struct *task,
4689 struct perf_event *event)
4691 struct perf_event_context *ctx, *clone_ctx = NULL;
4692 struct perf_cpu_context *cpuctx;
4693 void *task_ctx_data = NULL;
4694 unsigned long flags;
4696 int cpu = event->cpu;
4699 /* Must be root to operate on a CPU event: */
4700 err = perf_allow_cpu(&event->attr);
4702 return ERR_PTR(err);
4704 cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
4707 raw_spin_lock_irqsave(&ctx->lock, flags);
4709 raw_spin_unlock_irqrestore(&ctx->lock, flags);
4715 ctxn = pmu->task_ctx_nr;
4719 if (event->attach_state & PERF_ATTACH_TASK_DATA) {
4720 task_ctx_data = alloc_task_ctx_data(pmu);
4721 if (!task_ctx_data) {
4728 ctx = perf_lock_task_context(task, ctxn, &flags);
4730 clone_ctx = unclone_ctx(ctx);
4733 if (task_ctx_data && !ctx->task_ctx_data) {
4734 ctx->task_ctx_data = task_ctx_data;
4735 task_ctx_data = NULL;
4737 raw_spin_unlock_irqrestore(&ctx->lock, flags);
4742 ctx = alloc_perf_context(pmu, task);
4747 if (task_ctx_data) {
4748 ctx->task_ctx_data = task_ctx_data;
4749 task_ctx_data = NULL;
4753 mutex_lock(&task->perf_event_mutex);
4755 * If it has already passed perf_event_exit_task().
4756 * we must see PF_EXITING, it takes this mutex too.
4758 if (task->flags & PF_EXITING)
4760 else if (task->perf_event_ctxp[ctxn])
4765 rcu_assign_pointer(task->perf_event_ctxp[ctxn], ctx);
4767 mutex_unlock(&task->perf_event_mutex);
4769 if (unlikely(err)) {
4778 free_task_ctx_data(pmu, task_ctx_data);
4782 free_task_ctx_data(pmu, task_ctx_data);
4783 return ERR_PTR(err);
4786 static void perf_event_free_filter(struct perf_event *event);
4788 static void free_event_rcu(struct rcu_head *head)
4790 struct perf_event *event;
4792 event = container_of(head, struct perf_event, rcu_head);
4794 put_pid_ns(event->ns);
4795 perf_event_free_filter(event);
4796 kmem_cache_free(perf_event_cache, event);
4799 static void ring_buffer_attach(struct perf_event *event,
4800 struct perf_buffer *rb);
4802 static void detach_sb_event(struct perf_event *event)
4804 struct pmu_event_list *pel = per_cpu_ptr(&pmu_sb_events, event->cpu);
4806 raw_spin_lock(&pel->lock);
4807 list_del_rcu(&event->sb_list);
4808 raw_spin_unlock(&pel->lock);
4811 static bool is_sb_event(struct perf_event *event)
4813 struct perf_event_attr *attr = &event->attr;
4818 if (event->attach_state & PERF_ATTACH_TASK)
4821 if (attr->mmap || attr->mmap_data || attr->mmap2 ||
4822 attr->comm || attr->comm_exec ||
4823 attr->task || attr->ksymbol ||
4824 attr->context_switch || attr->text_poke ||
4830 static void unaccount_pmu_sb_event(struct perf_event *event)
4832 if (is_sb_event(event))
4833 detach_sb_event(event);
4836 static void unaccount_event_cpu(struct perf_event *event, int cpu)
4841 if (is_cgroup_event(event))
4842 atomic_dec(&per_cpu(perf_cgroup_events, cpu));
4845 #ifdef CONFIG_NO_HZ_FULL
4846 static DEFINE_SPINLOCK(nr_freq_lock);
4849 static void unaccount_freq_event_nohz(void)
4851 #ifdef CONFIG_NO_HZ_FULL
4852 spin_lock(&nr_freq_lock);
4853 if (atomic_dec_and_test(&nr_freq_events))
4854 tick_nohz_dep_clear(TICK_DEP_BIT_PERF_EVENTS);
4855 spin_unlock(&nr_freq_lock);
4859 static void unaccount_freq_event(void)
4861 if (tick_nohz_full_enabled())
4862 unaccount_freq_event_nohz();
4864 atomic_dec(&nr_freq_events);
4867 static void unaccount_event(struct perf_event *event)
4874 if (event->attach_state & (PERF_ATTACH_TASK | PERF_ATTACH_SCHED_CB))
4876 if (event->attr.mmap || event->attr.mmap_data)
4877 atomic_dec(&nr_mmap_events);
4878 if (event->attr.build_id)
4879 atomic_dec(&nr_build_id_events);
4880 if (event->attr.comm)
4881 atomic_dec(&nr_comm_events);
4882 if (event->attr.namespaces)
4883 atomic_dec(&nr_namespaces_events);
4884 if (event->attr.cgroup)
4885 atomic_dec(&nr_cgroup_events);
4886 if (event->attr.task)
4887 atomic_dec(&nr_task_events);
4888 if (event->attr.freq)
4889 unaccount_freq_event();
4890 if (event->attr.context_switch) {
4892 atomic_dec(&nr_switch_events);
4894 if (is_cgroup_event(event))
4896 if (has_branch_stack(event))
4898 if (event->attr.ksymbol)
4899 atomic_dec(&nr_ksymbol_events);
4900 if (event->attr.bpf_event)
4901 atomic_dec(&nr_bpf_events);
4902 if (event->attr.text_poke)
4903 atomic_dec(&nr_text_poke_events);
4906 if (!atomic_add_unless(&perf_sched_count, -1, 1))
4907 schedule_delayed_work(&perf_sched_work, HZ);
4910 unaccount_event_cpu(event, event->cpu);
4912 unaccount_pmu_sb_event(event);
4915 static void perf_sched_delayed(struct work_struct *work)
4917 mutex_lock(&perf_sched_mutex);
4918 if (atomic_dec_and_test(&perf_sched_count))
4919 static_branch_disable(&perf_sched_events);
4920 mutex_unlock(&perf_sched_mutex);
4924 * The following implement mutual exclusion of events on "exclusive" pmus
4925 * (PERF_PMU_CAP_EXCLUSIVE). Such pmus can only have one event scheduled
4926 * at a time, so we disallow creating events that might conflict, namely:
4928 * 1) cpu-wide events in the presence of per-task events,
4929 * 2) per-task events in the presence of cpu-wide events,
4930 * 3) two matching events on the same context.
4932 * The former two cases are handled in the allocation path (perf_event_alloc(),
4933 * _free_event()), the latter -- before the first perf_install_in_context().
4935 static int exclusive_event_init(struct perf_event *event)
4937 struct pmu *pmu = event->pmu;
4939 if (!is_exclusive_pmu(pmu))
4943 * Prevent co-existence of per-task and cpu-wide events on the
4944 * same exclusive pmu.
4946 * Negative pmu::exclusive_cnt means there are cpu-wide
4947 * events on this "exclusive" pmu, positive means there are
4950 * Since this is called in perf_event_alloc() path, event::ctx
4951 * doesn't exist yet; it is, however, safe to use PERF_ATTACH_TASK
4952 * to mean "per-task event", because unlike other attach states it
4953 * never gets cleared.
4955 if (event->attach_state & PERF_ATTACH_TASK) {
4956 if (!atomic_inc_unless_negative(&pmu->exclusive_cnt))
4959 if (!atomic_dec_unless_positive(&pmu->exclusive_cnt))
4966 static void exclusive_event_destroy(struct perf_event *event)
4968 struct pmu *pmu = event->pmu;
4970 if (!is_exclusive_pmu(pmu))
4973 /* see comment in exclusive_event_init() */
4974 if (event->attach_state & PERF_ATTACH_TASK)
4975 atomic_dec(&pmu->exclusive_cnt);
4977 atomic_inc(&pmu->exclusive_cnt);
4980 static bool exclusive_event_match(struct perf_event *e1, struct perf_event *e2)
4982 if ((e1->pmu == e2->pmu) &&
4983 (e1->cpu == e2->cpu ||
4990 static bool exclusive_event_installable(struct perf_event *event,
4991 struct perf_event_context *ctx)
4993 struct perf_event *iter_event;
4994 struct pmu *pmu = event->pmu;
4996 lockdep_assert_held(&ctx->mutex);
4998 if (!is_exclusive_pmu(pmu))
5001 list_for_each_entry(iter_event, &ctx->event_list, event_entry) {
5002 if (exclusive_event_match(iter_event, event))
5009 static void perf_addr_filters_splice(struct perf_event *event,
5010 struct list_head *head);
5012 static void _free_event(struct perf_event *event)
5014 irq_work_sync(&event->pending);
5016 unaccount_event(event);
5018 security_perf_event_free(event);
5022 * Can happen when we close an event with re-directed output.
5024 * Since we have a 0 refcount, perf_mmap_close() will skip
5025 * over us; possibly making our ring_buffer_put() the last.
5027 mutex_lock(&event->mmap_mutex);
5028 ring_buffer_attach(event, NULL);
5029 mutex_unlock(&event->mmap_mutex);
5032 if (is_cgroup_event(event))
5033 perf_detach_cgroup(event);
5035 if (!event->parent) {
5036 if (event->attr.sample_type & PERF_SAMPLE_CALLCHAIN)
5037 put_callchain_buffers();
5040 perf_event_free_bpf_prog(event);
5041 perf_addr_filters_splice(event, NULL);
5042 kfree(event->addr_filter_ranges);
5045 event->destroy(event);
5048 * Must be after ->destroy(), due to uprobe_perf_close() using
5051 if (event->hw.target)
5052 put_task_struct(event->hw.target);
5055 * perf_event_free_task() relies on put_ctx() being 'last', in particular
5056 * all task references must be cleaned up.
5059 put_ctx(event->ctx);
5061 exclusive_event_destroy(event);
5062 module_put(event->pmu->module);
5064 call_rcu(&event->rcu_head, free_event_rcu);
5068 * Used to free events which have a known refcount of 1, such as in error paths
5069 * where the event isn't exposed yet and inherited events.
5071 static void free_event(struct perf_event *event)
5073 if (WARN(atomic_long_cmpxchg(&event->refcount, 1, 0) != 1,
5074 "unexpected event refcount: %ld; ptr=%p\n",
5075 atomic_long_read(&event->refcount), event)) {
5076 /* leak to avoid use-after-free */
5084 * Remove user event from the owner task.
5086 static void perf_remove_from_owner(struct perf_event *event)
5088 struct task_struct *owner;
5092 * Matches the smp_store_release() in perf_event_exit_task(). If we
5093 * observe !owner it means the list deletion is complete and we can
5094 * indeed free this event, otherwise we need to serialize on
5095 * owner->perf_event_mutex.
5097 owner = READ_ONCE(event->owner);
5100 * Since delayed_put_task_struct() also drops the last
5101 * task reference we can safely take a new reference
5102 * while holding the rcu_read_lock().
5104 get_task_struct(owner);
5110 * If we're here through perf_event_exit_task() we're already
5111 * holding ctx->mutex which would be an inversion wrt. the
5112 * normal lock order.
5114 * However we can safely take this lock because its the child
5117 mutex_lock_nested(&owner->perf_event_mutex, SINGLE_DEPTH_NESTING);
5120 * We have to re-check the event->owner field, if it is cleared
5121 * we raced with perf_event_exit_task(), acquiring the mutex
5122 * ensured they're done, and we can proceed with freeing the
5126 list_del_init(&event->owner_entry);
5127 smp_store_release(&event->owner, NULL);
5129 mutex_unlock(&owner->perf_event_mutex);
5130 put_task_struct(owner);
5134 static void put_event(struct perf_event *event)
5136 if (!atomic_long_dec_and_test(&event->refcount))
5143 * Kill an event dead; while event:refcount will preserve the event
5144 * object, it will not preserve its functionality. Once the last 'user'
5145 * gives up the object, we'll destroy the thing.
5147 int perf_event_release_kernel(struct perf_event *event)
5149 struct perf_event_context *ctx = event->ctx;
5150 struct perf_event *child, *tmp;
5151 LIST_HEAD(free_list);
5154 * If we got here through err_file: fput(event_file); we will not have
5155 * attached to a context yet.
5158 WARN_ON_ONCE(event->attach_state &
5159 (PERF_ATTACH_CONTEXT|PERF_ATTACH_GROUP));
5163 if (!is_kernel_event(event))
5164 perf_remove_from_owner(event);
5166 ctx = perf_event_ctx_lock(event);
5167 WARN_ON_ONCE(ctx->parent_ctx);
5168 perf_remove_from_context(event, DETACH_GROUP);
5170 raw_spin_lock_irq(&ctx->lock);
5172 * Mark this event as STATE_DEAD, there is no external reference to it
5175 * Anybody acquiring event->child_mutex after the below loop _must_
5176 * also see this, most importantly inherit_event() which will avoid
5177 * placing more children on the list.
5179 * Thus this guarantees that we will in fact observe and kill _ALL_
5182 event->state = PERF_EVENT_STATE_DEAD;
5183 raw_spin_unlock_irq(&ctx->lock);
5185 perf_event_ctx_unlock(event, ctx);
5188 mutex_lock(&event->child_mutex);
5189 list_for_each_entry(child, &event->child_list, child_list) {
5192 * Cannot change, child events are not migrated, see the
5193 * comment with perf_event_ctx_lock_nested().
5195 ctx = READ_ONCE(child->ctx);
5197 * Since child_mutex nests inside ctx::mutex, we must jump
5198 * through hoops. We start by grabbing a reference on the ctx.
5200 * Since the event cannot get freed while we hold the
5201 * child_mutex, the context must also exist and have a !0
5207 * Now that we have a ctx ref, we can drop child_mutex, and
5208 * acquire ctx::mutex without fear of it going away. Then we
5209 * can re-acquire child_mutex.
5211 mutex_unlock(&event->child_mutex);
5212 mutex_lock(&ctx->mutex);
5213 mutex_lock(&event->child_mutex);
5216 * Now that we hold ctx::mutex and child_mutex, revalidate our
5217 * state, if child is still the first entry, it didn't get freed
5218 * and we can continue doing so.
5220 tmp = list_first_entry_or_null(&event->child_list,
5221 struct perf_event, child_list);
5223 perf_remove_from_context(child, DETACH_GROUP);
5224 list_move(&child->child_list, &free_list);
5226 * This matches the refcount bump in inherit_event();
5227 * this can't be the last reference.
5232 mutex_unlock(&event->child_mutex);
5233 mutex_unlock(&ctx->mutex);
5237 mutex_unlock(&event->child_mutex);
5239 list_for_each_entry_safe(child, tmp, &free_list, child_list) {
5240 void *var = &child->ctx->refcount;
5242 list_del(&child->child_list);
5246 * Wake any perf_event_free_task() waiting for this event to be
5249 smp_mb(); /* pairs with wait_var_event() */
5254 put_event(event); /* Must be the 'last' reference */
5257 EXPORT_SYMBOL_GPL(perf_event_release_kernel);
5260 * Called when the last reference to the file is gone.
5262 static int perf_release(struct inode *inode, struct file *file)
5264 perf_event_release_kernel(file->private_data);
5268 static u64 __perf_event_read_value(struct perf_event *event, u64 *enabled, u64 *running)
5270 struct perf_event *child;
5276 mutex_lock(&event->child_mutex);
5278 (void)perf_event_read(event, false);
5279 total += perf_event_count(event);
5281 *enabled += event->total_time_enabled +
5282 atomic64_read(&event->child_total_time_enabled);
5283 *running += event->total_time_running +
5284 atomic64_read(&event->child_total_time_running);
5286 list_for_each_entry(child, &event->child_list, child_list) {
5287 (void)perf_event_read(child, false);
5288 total += perf_event_count(child);
5289 *enabled += child->total_time_enabled;
5290 *running += child->total_time_running;
5292 mutex_unlock(&event->child_mutex);
5297 u64 perf_event_read_value(struct perf_event *event, u64 *enabled, u64 *running)
5299 struct perf_event_context *ctx;
5302 ctx = perf_event_ctx_lock(event);
5303 count = __perf_event_read_value(event, enabled, running);
5304 perf_event_ctx_unlock(event, ctx);
5308 EXPORT_SYMBOL_GPL(perf_event_read_value);
5310 static int __perf_read_group_add(struct perf_event *leader,
5311 u64 read_format, u64 *values)
5313 struct perf_event_context *ctx = leader->ctx;
5314 struct perf_event *sub;
5315 unsigned long flags;
5316 int n = 1; /* skip @nr */
5319 ret = perf_event_read(leader, true);
5323 raw_spin_lock_irqsave(&ctx->lock, flags);
5326 * Since we co-schedule groups, {enabled,running} times of siblings
5327 * will be identical to those of the leader, so we only publish one
5330 if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED) {
5331 values[n++] += leader->total_time_enabled +
5332 atomic64_read(&leader->child_total_time_enabled);
5335 if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING) {
5336 values[n++] += leader->total_time_running +
5337 atomic64_read(&leader->child_total_time_running);
5341 * Write {count,id} tuples for every sibling.
5343 values[n++] += perf_event_count(leader);
5344 if (read_format & PERF_FORMAT_ID)
5345 values[n++] = primary_event_id(leader);
5347 for_each_sibling_event(sub, leader) {
5348 values[n++] += perf_event_count(sub);
5349 if (read_format & PERF_FORMAT_ID)
5350 values[n++] = primary_event_id(sub);
5353 raw_spin_unlock_irqrestore(&ctx->lock, flags);
5357 static int perf_read_group(struct perf_event *event,
5358 u64 read_format, char __user *buf)
5360 struct perf_event *leader = event->group_leader, *child;
5361 struct perf_event_context *ctx = leader->ctx;
5365 lockdep_assert_held(&ctx->mutex);
5367 values = kzalloc(event->read_size, GFP_KERNEL);
5371 values[0] = 1 + leader->nr_siblings;
5374 * By locking the child_mutex of the leader we effectively
5375 * lock the child list of all siblings.. XXX explain how.
5377 mutex_lock(&leader->child_mutex);
5379 ret = __perf_read_group_add(leader, read_format, values);
5383 list_for_each_entry(child, &leader->child_list, child_list) {
5384 ret = __perf_read_group_add(child, read_format, values);
5389 mutex_unlock(&leader->child_mutex);
5391 ret = event->read_size;
5392 if (copy_to_user(buf, values, event->read_size))
5397 mutex_unlock(&leader->child_mutex);
5403 static int perf_read_one(struct perf_event *event,
5404 u64 read_format, char __user *buf)
5406 u64 enabled, running;
5410 values[n++] = __perf_event_read_value(event, &enabled, &running);
5411 if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED)
5412 values[n++] = enabled;
5413 if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING)
5414 values[n++] = running;
5415 if (read_format & PERF_FORMAT_ID)
5416 values[n++] = primary_event_id(event);
5418 if (copy_to_user(buf, values, n * sizeof(u64)))
5421 return n * sizeof(u64);
5424 static bool is_event_hup(struct perf_event *event)
5428 if (event->state > PERF_EVENT_STATE_EXIT)
5431 mutex_lock(&event->child_mutex);
5432 no_children = list_empty(&event->child_list);
5433 mutex_unlock(&event->child_mutex);
5438 * Read the performance event - simple non blocking version for now
5441 __perf_read(struct perf_event *event, char __user *buf, size_t count)
5443 u64 read_format = event->attr.read_format;
5447 * Return end-of-file for a read on an event that is in
5448 * error state (i.e. because it was pinned but it couldn't be
5449 * scheduled on to the CPU at some point).
5451 if (event->state == PERF_EVENT_STATE_ERROR)
5454 if (count < event->read_size)
5457 WARN_ON_ONCE(event->ctx->parent_ctx);
5458 if (read_format & PERF_FORMAT_GROUP)
5459 ret = perf_read_group(event, read_format, buf);
5461 ret = perf_read_one(event, read_format, buf);
5467 perf_read(struct file *file, char __user *buf, size_t count, loff_t *ppos)
5469 struct perf_event *event = file->private_data;
5470 struct perf_event_context *ctx;
5473 ret = security_perf_event_read(event);
5477 ctx = perf_event_ctx_lock(event);
5478 ret = __perf_read(event, buf, count);
5479 perf_event_ctx_unlock(event, ctx);
5484 static __poll_t perf_poll(struct file *file, poll_table *wait)
5486 struct perf_event *event = file->private_data;
5487 struct perf_buffer *rb;
5488 __poll_t events = EPOLLHUP;
5490 poll_wait(file, &event->waitq, wait);
5492 if (is_event_hup(event))
5496 * Pin the event->rb by taking event->mmap_mutex; otherwise
5497 * perf_event_set_output() can swizzle our rb and make us miss wakeups.
5499 mutex_lock(&event->mmap_mutex);
5502 events = atomic_xchg(&rb->poll, 0);
5503 mutex_unlock(&event->mmap_mutex);
5507 static void _perf_event_reset(struct perf_event *event)
5509 (void)perf_event_read(event, false);
5510 local64_set(&event->count, 0);
5511 perf_event_update_userpage(event);
5514 /* Assume it's not an event with inherit set. */
5515 u64 perf_event_pause(struct perf_event *event, bool reset)
5517 struct perf_event_context *ctx;
5520 ctx = perf_event_ctx_lock(event);
5521 WARN_ON_ONCE(event->attr.inherit);
5522 _perf_event_disable(event);
5523 count = local64_read(&event->count);
5525 local64_set(&event->count, 0);
5526 perf_event_ctx_unlock(event, ctx);
5530 EXPORT_SYMBOL_GPL(perf_event_pause);
5533 * Holding the top-level event's child_mutex means that any
5534 * descendant process that has inherited this event will block
5535 * in perf_event_exit_event() if it goes to exit, thus satisfying the
5536 * task existence requirements of perf_event_enable/disable.
5538 static void perf_event_for_each_child(struct perf_event *event,
5539 void (*func)(struct perf_event *))
5541 struct perf_event *child;
5543 WARN_ON_ONCE(event->ctx->parent_ctx);
5545 mutex_lock(&event->child_mutex);
5547 list_for_each_entry(child, &event->child_list, child_list)
5549 mutex_unlock(&event->child_mutex);
5552 static void perf_event_for_each(struct perf_event *event,
5553 void (*func)(struct perf_event *))
5555 struct perf_event_context *ctx = event->ctx;
5556 struct perf_event *sibling;
5558 lockdep_assert_held(&ctx->mutex);
5560 event = event->group_leader;
5562 perf_event_for_each_child(event, func);
5563 for_each_sibling_event(sibling, event)
5564 perf_event_for_each_child(sibling, func);
5567 static void __perf_event_period(struct perf_event *event,
5568 struct perf_cpu_context *cpuctx,
5569 struct perf_event_context *ctx,
5572 u64 value = *((u64 *)info);
5575 if (event->attr.freq) {
5576 event->attr.sample_freq = value;
5578 event->attr.sample_period = value;
5579 event->hw.sample_period = value;
5582 active = (event->state == PERF_EVENT_STATE_ACTIVE);
5584 perf_pmu_disable(ctx->pmu);
5586 * We could be throttled; unthrottle now to avoid the tick
5587 * trying to unthrottle while we already re-started the event.
5589 if (event->hw.interrupts == MAX_INTERRUPTS) {
5590 event->hw.interrupts = 0;
5591 perf_log_throttle(event, 1);
5593 event->pmu->stop(event, PERF_EF_UPDATE);
5596 local64_set(&event->hw.period_left, 0);
5599 event->pmu->start(event, PERF_EF_RELOAD);
5600 perf_pmu_enable(ctx->pmu);
5604 static int perf_event_check_period(struct perf_event *event, u64 value)
5606 return event->pmu->check_period(event, value);
5609 static int _perf_event_period(struct perf_event *event, u64 value)
5611 if (!is_sampling_event(event))
5617 if (event->attr.freq && value > sysctl_perf_event_sample_rate)
5620 if (perf_event_check_period(event, value))
5623 if (!event->attr.freq && (value & (1ULL << 63)))
5626 event_function_call(event, __perf_event_period, &value);
5631 int perf_event_period(struct perf_event *event, u64 value)
5633 struct perf_event_context *ctx;
5636 ctx = perf_event_ctx_lock(event);
5637 ret = _perf_event_period(event, value);
5638 perf_event_ctx_unlock(event, ctx);
5642 EXPORT_SYMBOL_GPL(perf_event_period);
5644 static const struct file_operations perf_fops;
5646 static inline int perf_fget_light(int fd, struct fd *p)
5648 struct fd f = fdget(fd);
5652 if (f.file->f_op != &perf_fops) {
5660 static int perf_event_set_output(struct perf_event *event,
5661 struct perf_event *output_event);
5662 static int perf_event_set_filter(struct perf_event *event, void __user *arg);
5663 static int perf_copy_attr(struct perf_event_attr __user *uattr,
5664 struct perf_event_attr *attr);
5666 static long _perf_ioctl(struct perf_event *event, unsigned int cmd, unsigned long arg)
5668 void (*func)(struct perf_event *);
5672 case PERF_EVENT_IOC_ENABLE:
5673 func = _perf_event_enable;
5675 case PERF_EVENT_IOC_DISABLE:
5676 func = _perf_event_disable;
5678 case PERF_EVENT_IOC_RESET:
5679 func = _perf_event_reset;
5682 case PERF_EVENT_IOC_REFRESH:
5683 return _perf_event_refresh(event, arg);
5685 case PERF_EVENT_IOC_PERIOD:
5689 if (copy_from_user(&value, (u64 __user *)arg, sizeof(value)))
5692 return _perf_event_period(event, value);
5694 case PERF_EVENT_IOC_ID:
5696 u64 id = primary_event_id(event);
5698 if (copy_to_user((void __user *)arg, &id, sizeof(id)))
5703 case PERF_EVENT_IOC_SET_OUTPUT:
5707 struct perf_event *output_event;
5709 ret = perf_fget_light(arg, &output);
5712 output_event = output.file->private_data;
5713 ret = perf_event_set_output(event, output_event);
5716 ret = perf_event_set_output(event, NULL);
5721 case PERF_EVENT_IOC_SET_FILTER:
5722 return perf_event_set_filter(event, (void __user *)arg);
5724 case PERF_EVENT_IOC_SET_BPF:
5726 struct bpf_prog *prog;
5729 prog = bpf_prog_get(arg);
5731 return PTR_ERR(prog);
5733 err = perf_event_set_bpf_prog(event, prog, 0);
5742 case PERF_EVENT_IOC_PAUSE_OUTPUT: {
5743 struct perf_buffer *rb;
5746 rb = rcu_dereference(event->rb);
5747 if (!rb || !rb->nr_pages) {
5751 rb_toggle_paused(rb, !!arg);
5756 case PERF_EVENT_IOC_QUERY_BPF:
5757 return perf_event_query_prog_array(event, (void __user *)arg);
5759 case PERF_EVENT_IOC_MODIFY_ATTRIBUTES: {
5760 struct perf_event_attr new_attr;
5761 int err = perf_copy_attr((struct perf_event_attr __user *)arg,
5767 return perf_event_modify_attr(event, &new_attr);
5773 if (flags & PERF_IOC_FLAG_GROUP)
5774 perf_event_for_each(event, func);
5776 perf_event_for_each_child(event, func);
5781 static long perf_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
5783 struct perf_event *event = file->private_data;
5784 struct perf_event_context *ctx;
5787 /* Treat ioctl like writes as it is likely a mutating operation. */
5788 ret = security_perf_event_write(event);
5792 ctx = perf_event_ctx_lock(event);
5793 ret = _perf_ioctl(event, cmd, arg);
5794 perf_event_ctx_unlock(event, ctx);
5799 #ifdef CONFIG_COMPAT
5800 static long perf_compat_ioctl(struct file *file, unsigned int cmd,
5803 switch (_IOC_NR(cmd)) {
5804 case _IOC_NR(PERF_EVENT_IOC_SET_FILTER):
5805 case _IOC_NR(PERF_EVENT_IOC_ID):
5806 case _IOC_NR(PERF_EVENT_IOC_QUERY_BPF):
5807 case _IOC_NR(PERF_EVENT_IOC_MODIFY_ATTRIBUTES):
5808 /* Fix up pointer size (usually 4 -> 8 in 32-on-64-bit case */
5809 if (_IOC_SIZE(cmd) == sizeof(compat_uptr_t)) {
5810 cmd &= ~IOCSIZE_MASK;
5811 cmd |= sizeof(void *) << IOCSIZE_SHIFT;
5815 return perf_ioctl(file, cmd, arg);
5818 # define perf_compat_ioctl NULL
5821 int perf_event_task_enable(void)
5823 struct perf_event_context *ctx;
5824 struct perf_event *event;
5826 mutex_lock(¤t->perf_event_mutex);
5827 list_for_each_entry(event, ¤t->perf_event_list, owner_entry) {
5828 ctx = perf_event_ctx_lock(event);
5829 perf_event_for_each_child(event, _perf_event_enable);
5830 perf_event_ctx_unlock(event, ctx);
5832 mutex_unlock(¤t->perf_event_mutex);
5837 int perf_event_task_disable(void)
5839 struct perf_event_context *ctx;
5840 struct perf_event *event;
5842 mutex_lock(¤t->perf_event_mutex);
5843 list_for_each_entry(event, ¤t->perf_event_list, owner_entry) {
5844 ctx = perf_event_ctx_lock(event);
5845 perf_event_for_each_child(event, _perf_event_disable);
5846 perf_event_ctx_unlock(event, ctx);
5848 mutex_unlock(¤t->perf_event_mutex);
5853 static int perf_event_index(struct perf_event *event)
5855 if (event->hw.state & PERF_HES_STOPPED)
5858 if (event->state != PERF_EVENT_STATE_ACTIVE)
5861 return event->pmu->event_idx(event);
5864 static void perf_event_init_userpage(struct perf_event *event)
5866 struct perf_event_mmap_page *userpg;
5867 struct perf_buffer *rb;
5870 rb = rcu_dereference(event->rb);
5874 userpg = rb->user_page;
5876 /* Allow new userspace to detect that bit 0 is deprecated */
5877 userpg->cap_bit0_is_deprecated = 1;
5878 userpg->size = offsetof(struct perf_event_mmap_page, __reserved);
5879 userpg->data_offset = PAGE_SIZE;
5880 userpg->data_size = perf_data_size(rb);
5886 void __weak arch_perf_update_userpage(
5887 struct perf_event *event, struct perf_event_mmap_page *userpg, u64 now)
5892 * Callers need to ensure there can be no nesting of this function, otherwise
5893 * the seqlock logic goes bad. We can not serialize this because the arch
5894 * code calls this from NMI context.
5896 void perf_event_update_userpage(struct perf_event *event)
5898 struct perf_event_mmap_page *userpg;
5899 struct perf_buffer *rb;
5900 u64 enabled, running, now;
5903 rb = rcu_dereference(event->rb);
5908 * compute total_time_enabled, total_time_running
5909 * based on snapshot values taken when the event
5910 * was last scheduled in.
5912 * we cannot simply called update_context_time()
5913 * because of locking issue as we can be called in
5916 calc_timer_values(event, &now, &enabled, &running);
5918 userpg = rb->user_page;
5920 * Disable preemption to guarantee consistent time stamps are stored to
5926 userpg->index = perf_event_index(event);
5927 userpg->offset = perf_event_count(event);
5929 userpg->offset -= local64_read(&event->hw.prev_count);
5931 userpg->time_enabled = enabled +
5932 atomic64_read(&event->child_total_time_enabled);
5934 userpg->time_running = running +
5935 atomic64_read(&event->child_total_time_running);
5937 arch_perf_update_userpage(event, userpg, now);
5945 EXPORT_SYMBOL_GPL(perf_event_update_userpage);
5947 static vm_fault_t perf_mmap_fault(struct vm_fault *vmf)
5949 struct perf_event *event = vmf->vma->vm_file->private_data;
5950 struct perf_buffer *rb;
5951 vm_fault_t ret = VM_FAULT_SIGBUS;
5953 if (vmf->flags & FAULT_FLAG_MKWRITE) {
5954 if (vmf->pgoff == 0)
5960 rb = rcu_dereference(event->rb);
5964 if (vmf->pgoff && (vmf->flags & FAULT_FLAG_WRITE))
5967 vmf->page = perf_mmap_to_page(rb, vmf->pgoff);
5971 get_page(vmf->page);
5972 vmf->page->mapping = vmf->vma->vm_file->f_mapping;
5973 vmf->page->index = vmf->pgoff;
5982 static void ring_buffer_attach(struct perf_event *event,
5983 struct perf_buffer *rb)
5985 struct perf_buffer *old_rb = NULL;
5986 unsigned long flags;
5990 * Should be impossible, we set this when removing
5991 * event->rb_entry and wait/clear when adding event->rb_entry.
5993 WARN_ON_ONCE(event->rcu_pending);
5996 spin_lock_irqsave(&old_rb->event_lock, flags);
5997 list_del_rcu(&event->rb_entry);
5998 spin_unlock_irqrestore(&old_rb->event_lock, flags);
6000 event->rcu_batches = get_state_synchronize_rcu();
6001 event->rcu_pending = 1;
6005 if (event->rcu_pending) {
6006 cond_synchronize_rcu(event->rcu_batches);
6007 event->rcu_pending = 0;
6010 spin_lock_irqsave(&rb->event_lock, flags);
6011 list_add_rcu(&event->rb_entry, &rb->event_list);
6012 spin_unlock_irqrestore(&rb->event_lock, flags);
6016 * Avoid racing with perf_mmap_close(AUX): stop the event
6017 * before swizzling the event::rb pointer; if it's getting
6018 * unmapped, its aux_mmap_count will be 0 and it won't
6019 * restart. See the comment in __perf_pmu_output_stop().
6021 * Data will inevitably be lost when set_output is done in
6022 * mid-air, but then again, whoever does it like this is
6023 * not in for the data anyway.
6026 perf_event_stop(event, 0);
6028 rcu_assign_pointer(event->rb, rb);
6031 ring_buffer_put(old_rb);
6033 * Since we detached before setting the new rb, so that we
6034 * could attach the new rb, we could have missed a wakeup.
6037 wake_up_all(&event->waitq);
6041 static void ring_buffer_wakeup(struct perf_event *event)
6043 struct perf_buffer *rb;
6046 rb = rcu_dereference(event->rb);
6048 list_for_each_entry_rcu(event, &rb->event_list, rb_entry)
6049 wake_up_all(&event->waitq);
6054 struct perf_buffer *ring_buffer_get(struct perf_event *event)
6056 struct perf_buffer *rb;
6059 rb = rcu_dereference(event->rb);
6061 if (!refcount_inc_not_zero(&rb->refcount))
6069 void ring_buffer_put(struct perf_buffer *rb)
6071 if (!refcount_dec_and_test(&rb->refcount))
6074 WARN_ON_ONCE(!list_empty(&rb->event_list));
6076 call_rcu(&rb->rcu_head, rb_free_rcu);
6079 static void perf_mmap_open(struct vm_area_struct *vma)
6081 struct perf_event *event = vma->vm_file->private_data;
6083 atomic_inc(&event->mmap_count);
6084 atomic_inc(&event->rb->mmap_count);
6087 atomic_inc(&event->rb->aux_mmap_count);
6089 if (event->pmu->event_mapped)
6090 event->pmu->event_mapped(event, vma->vm_mm);
6093 static void perf_pmu_output_stop(struct perf_event *event);
6096 * A buffer can be mmap()ed multiple times; either directly through the same
6097 * event, or through other events by use of perf_event_set_output().
6099 * In order to undo the VM accounting done by perf_mmap() we need to destroy
6100 * the buffer here, where we still have a VM context. This means we need
6101 * to detach all events redirecting to us.
6103 static void perf_mmap_close(struct vm_area_struct *vma)
6105 struct perf_event *event = vma->vm_file->private_data;
6106 struct perf_buffer *rb = ring_buffer_get(event);
6107 struct user_struct *mmap_user = rb->mmap_user;
6108 int mmap_locked = rb->mmap_locked;
6109 unsigned long size = perf_data_size(rb);
6110 bool detach_rest = false;
6112 if (event->pmu->event_unmapped)
6113 event->pmu->event_unmapped(event, vma->vm_mm);
6116 * rb->aux_mmap_count will always drop before rb->mmap_count and
6117 * event->mmap_count, so it is ok to use event->mmap_mutex to
6118 * serialize with perf_mmap here.
6120 if (rb_has_aux(rb) && vma->vm_pgoff == rb->aux_pgoff &&
6121 atomic_dec_and_mutex_lock(&rb->aux_mmap_count, &event->mmap_mutex)) {
6123 * Stop all AUX events that are writing to this buffer,
6124 * so that we can free its AUX pages and corresponding PMU
6125 * data. Note that after rb::aux_mmap_count dropped to zero,
6126 * they won't start any more (see perf_aux_output_begin()).
6128 perf_pmu_output_stop(event);
6130 /* now it's safe to free the pages */
6131 atomic_long_sub(rb->aux_nr_pages - rb->aux_mmap_locked, &mmap_user->locked_vm);
6132 atomic64_sub(rb->aux_mmap_locked, &vma->vm_mm->pinned_vm);
6134 /* this has to be the last one */
6136 WARN_ON_ONCE(refcount_read(&rb->aux_refcount));
6138 mutex_unlock(&event->mmap_mutex);
6141 if (atomic_dec_and_test(&rb->mmap_count))
6144 if (!atomic_dec_and_mutex_lock(&event->mmap_count, &event->mmap_mutex))
6147 ring_buffer_attach(event, NULL);
6148 mutex_unlock(&event->mmap_mutex);
6150 /* If there's still other mmap()s of this buffer, we're done. */
6155 * No other mmap()s, detach from all other events that might redirect
6156 * into the now unreachable buffer. Somewhat complicated by the
6157 * fact that rb::event_lock otherwise nests inside mmap_mutex.
6161 list_for_each_entry_rcu(event, &rb->event_list, rb_entry) {
6162 if (!atomic_long_inc_not_zero(&event->refcount)) {
6164 * This event is en-route to free_event() which will
6165 * detach it and remove it from the list.
6171 mutex_lock(&event->mmap_mutex);
6173 * Check we didn't race with perf_event_set_output() which can
6174 * swizzle the rb from under us while we were waiting to
6175 * acquire mmap_mutex.
6177 * If we find a different rb; ignore this event, a next
6178 * iteration will no longer find it on the list. We have to
6179 * still restart the iteration to make sure we're not now
6180 * iterating the wrong list.
6182 if (event->rb == rb)
6183 ring_buffer_attach(event, NULL);
6185 mutex_unlock(&event->mmap_mutex);
6189 * Restart the iteration; either we're on the wrong list or
6190 * destroyed its integrity by doing a deletion.
6197 * It could be there's still a few 0-ref events on the list; they'll
6198 * get cleaned up by free_event() -- they'll also still have their
6199 * ref on the rb and will free it whenever they are done with it.
6201 * Aside from that, this buffer is 'fully' detached and unmapped,
6202 * undo the VM accounting.
6205 atomic_long_sub((size >> PAGE_SHIFT) + 1 - mmap_locked,
6206 &mmap_user->locked_vm);
6207 atomic64_sub(mmap_locked, &vma->vm_mm->pinned_vm);
6208 free_uid(mmap_user);
6211 ring_buffer_put(rb); /* could be last */
6214 static const struct vm_operations_struct perf_mmap_vmops = {
6215 .open = perf_mmap_open,
6216 .close = perf_mmap_close, /* non mergeable */
6217 .fault = perf_mmap_fault,
6218 .page_mkwrite = perf_mmap_fault,
6221 static int perf_mmap(struct file *file, struct vm_area_struct *vma)
6223 struct perf_event *event = file->private_data;
6224 unsigned long user_locked, user_lock_limit;
6225 struct user_struct *user = current_user();
6226 struct perf_buffer *rb = NULL;
6227 unsigned long locked, lock_limit;
6228 unsigned long vma_size;
6229 unsigned long nr_pages;
6230 long user_extra = 0, extra = 0;
6231 int ret = 0, flags = 0;
6234 * Don't allow mmap() of inherited per-task counters. This would
6235 * create a performance issue due to all children writing to the
6238 if (event->cpu == -1 && event->attr.inherit)
6241 if (!(vma->vm_flags & VM_SHARED))
6244 ret = security_perf_event_read(event);
6248 vma_size = vma->vm_end - vma->vm_start;
6250 if (vma->vm_pgoff == 0) {
6251 nr_pages = (vma_size / PAGE_SIZE) - 1;
6254 * AUX area mapping: if rb->aux_nr_pages != 0, it's already
6255 * mapped, all subsequent mappings should have the same size
6256 * and offset. Must be above the normal perf buffer.
6258 u64 aux_offset, aux_size;
6263 nr_pages = vma_size / PAGE_SIZE;
6265 mutex_lock(&event->mmap_mutex);
6272 aux_offset = READ_ONCE(rb->user_page->aux_offset);
6273 aux_size = READ_ONCE(rb->user_page->aux_size);
6275 if (aux_offset < perf_data_size(rb) + PAGE_SIZE)
6278 if (aux_offset != vma->vm_pgoff << PAGE_SHIFT)
6281 /* already mapped with a different offset */
6282 if (rb_has_aux(rb) && rb->aux_pgoff != vma->vm_pgoff)
6285 if (aux_size != vma_size || aux_size != nr_pages * PAGE_SIZE)
6288 /* already mapped with a different size */
6289 if (rb_has_aux(rb) && rb->aux_nr_pages != nr_pages)
6292 if (!is_power_of_2(nr_pages))
6295 if (!atomic_inc_not_zero(&rb->mmap_count))
6298 if (rb_has_aux(rb)) {
6299 atomic_inc(&rb->aux_mmap_count);
6304 atomic_set(&rb->aux_mmap_count, 1);
6305 user_extra = nr_pages;
6311 * If we have rb pages ensure they're a power-of-two number, so we
6312 * can do bitmasks instead of modulo.
6314 if (nr_pages != 0 && !is_power_of_2(nr_pages))
6317 if (vma_size != PAGE_SIZE * (1 + nr_pages))
6320 WARN_ON_ONCE(event->ctx->parent_ctx);
6322 mutex_lock(&event->mmap_mutex);
6324 if (event->rb->nr_pages != nr_pages) {
6329 if (!atomic_inc_not_zero(&event->rb->mmap_count)) {
6331 * Raced against perf_mmap_close() through
6332 * perf_event_set_output(). Try again, hope for better
6335 mutex_unlock(&event->mmap_mutex);
6342 user_extra = nr_pages + 1;
6345 user_lock_limit = sysctl_perf_event_mlock >> (PAGE_SHIFT - 10);
6348 * Increase the limit linearly with more CPUs:
6350 user_lock_limit *= num_online_cpus();
6352 user_locked = atomic_long_read(&user->locked_vm);
6355 * sysctl_perf_event_mlock may have changed, so that
6356 * user->locked_vm > user_lock_limit
6358 if (user_locked > user_lock_limit)
6359 user_locked = user_lock_limit;
6360 user_locked += user_extra;
6362 if (user_locked > user_lock_limit) {
6364 * charge locked_vm until it hits user_lock_limit;
6365 * charge the rest from pinned_vm
6367 extra = user_locked - user_lock_limit;
6368 user_extra -= extra;
6371 lock_limit = rlimit(RLIMIT_MEMLOCK);
6372 lock_limit >>= PAGE_SHIFT;
6373 locked = atomic64_read(&vma->vm_mm->pinned_vm) + extra;
6375 if ((locked > lock_limit) && perf_is_paranoid() &&
6376 !capable(CAP_IPC_LOCK)) {
6381 WARN_ON(!rb && event->rb);
6383 if (vma->vm_flags & VM_WRITE)
6384 flags |= RING_BUFFER_WRITABLE;
6387 rb = rb_alloc(nr_pages,
6388 event->attr.watermark ? event->attr.wakeup_watermark : 0,
6396 atomic_set(&rb->mmap_count, 1);
6397 rb->mmap_user = get_current_user();
6398 rb->mmap_locked = extra;
6400 ring_buffer_attach(event, rb);
6402 perf_event_update_time(event);
6403 perf_event_init_userpage(event);
6404 perf_event_update_userpage(event);
6406 ret = rb_alloc_aux(rb, event, vma->vm_pgoff, nr_pages,
6407 event->attr.aux_watermark, flags);
6409 rb->aux_mmap_locked = extra;
6414 atomic_long_add(user_extra, &user->locked_vm);
6415 atomic64_add(extra, &vma->vm_mm->pinned_vm);
6417 atomic_inc(&event->mmap_count);
6419 atomic_dec(&rb->mmap_count);
6422 mutex_unlock(&event->mmap_mutex);
6425 * Since pinned accounting is per vm we cannot allow fork() to copy our
6428 vma->vm_flags |= VM_DONTCOPY | VM_DONTEXPAND | VM_DONTDUMP;
6429 vma->vm_ops = &perf_mmap_vmops;
6431 if (event->pmu->event_mapped)
6432 event->pmu->event_mapped(event, vma->vm_mm);
6437 static int perf_fasync(int fd, struct file *filp, int on)
6439 struct inode *inode = file_inode(filp);
6440 struct perf_event *event = filp->private_data;
6444 retval = fasync_helper(fd, filp, on, &event->fasync);
6445 inode_unlock(inode);
6453 static const struct file_operations perf_fops = {
6454 .llseek = no_llseek,
6455 .release = perf_release,
6458 .unlocked_ioctl = perf_ioctl,
6459 .compat_ioctl = perf_compat_ioctl,
6461 .fasync = perf_fasync,
6467 * If there's data, ensure we set the poll() state and publish everything
6468 * to user-space before waking everybody up.
6471 static inline struct fasync_struct **perf_event_fasync(struct perf_event *event)
6473 /* only the parent has fasync state */
6475 event = event->parent;
6476 return &event->fasync;
6479 void perf_event_wakeup(struct perf_event *event)
6481 ring_buffer_wakeup(event);
6483 if (event->pending_kill) {
6484 kill_fasync(perf_event_fasync(event), SIGIO, event->pending_kill);
6485 event->pending_kill = 0;
6489 static void perf_sigtrap(struct perf_event *event)
6492 * We'd expect this to only occur if the irq_work is delayed and either
6493 * ctx->task or current has changed in the meantime. This can be the
6494 * case on architectures that do not implement arch_irq_work_raise().
6496 if (WARN_ON_ONCE(event->ctx->task != current))
6500 * perf_pending_event() can race with the task exiting.
6502 if (current->flags & PF_EXITING)
6505 force_sig_perf((void __user *)event->pending_addr,
6506 event->attr.type, event->attr.sig_data);
6509 static void perf_pending_event_disable(struct perf_event *event)
6511 int cpu = READ_ONCE(event->pending_disable);
6516 if (cpu == smp_processor_id()) {
6517 WRITE_ONCE(event->pending_disable, -1);
6519 if (event->attr.sigtrap) {
6520 perf_sigtrap(event);
6521 atomic_set_release(&event->event_limit, 1); /* rearm event */
6525 perf_event_disable_local(event);
6532 * perf_event_disable_inatomic()
6533 * @pending_disable = CPU-A;
6537 * @pending_disable = -1;
6540 * perf_event_disable_inatomic()
6541 * @pending_disable = CPU-B;
6542 * irq_work_queue(); // FAILS
6545 * perf_pending_event()
6547 * But the event runs on CPU-B and wants disabling there.
6549 irq_work_queue_on(&event->pending, cpu);
6552 static void perf_pending_event(struct irq_work *entry)
6554 struct perf_event *event = container_of(entry, struct perf_event, pending);
6557 rctx = perf_swevent_get_recursion_context();
6559 * If we 'fail' here, that's OK, it means recursion is already disabled
6560 * and we won't recurse 'further'.
6563 perf_pending_event_disable(event);
6565 if (event->pending_wakeup) {
6566 event->pending_wakeup = 0;
6567 perf_event_wakeup(event);
6571 perf_swevent_put_recursion_context(rctx);
6574 #ifdef CONFIG_GUEST_PERF_EVENTS
6575 struct perf_guest_info_callbacks __rcu *perf_guest_cbs;
6577 DEFINE_STATIC_CALL_RET0(__perf_guest_state, *perf_guest_cbs->state);
6578 DEFINE_STATIC_CALL_RET0(__perf_guest_get_ip, *perf_guest_cbs->get_ip);
6579 DEFINE_STATIC_CALL_RET0(__perf_guest_handle_intel_pt_intr, *perf_guest_cbs->handle_intel_pt_intr);
6581 void perf_register_guest_info_callbacks(struct perf_guest_info_callbacks *cbs)
6583 if (WARN_ON_ONCE(rcu_access_pointer(perf_guest_cbs)))
6586 rcu_assign_pointer(perf_guest_cbs, cbs);
6587 static_call_update(__perf_guest_state, cbs->state);
6588 static_call_update(__perf_guest_get_ip, cbs->get_ip);
6590 /* Implementing ->handle_intel_pt_intr is optional. */
6591 if (cbs->handle_intel_pt_intr)
6592 static_call_update(__perf_guest_handle_intel_pt_intr,
6593 cbs->handle_intel_pt_intr);
6595 EXPORT_SYMBOL_GPL(perf_register_guest_info_callbacks);
6597 void perf_unregister_guest_info_callbacks(struct perf_guest_info_callbacks *cbs)
6599 if (WARN_ON_ONCE(rcu_access_pointer(perf_guest_cbs) != cbs))
6602 rcu_assign_pointer(perf_guest_cbs, NULL);
6603 static_call_update(__perf_guest_state, (void *)&__static_call_return0);
6604 static_call_update(__perf_guest_get_ip, (void *)&__static_call_return0);
6605 static_call_update(__perf_guest_handle_intel_pt_intr,
6606 (void *)&__static_call_return0);
6609 EXPORT_SYMBOL_GPL(perf_unregister_guest_info_callbacks);
6613 perf_output_sample_regs(struct perf_output_handle *handle,
6614 struct pt_regs *regs, u64 mask)
6617 DECLARE_BITMAP(_mask, 64);
6619 bitmap_from_u64(_mask, mask);
6620 for_each_set_bit(bit, _mask, sizeof(mask) * BITS_PER_BYTE) {
6623 val = perf_reg_value(regs, bit);
6624 perf_output_put(handle, val);
6628 static void perf_sample_regs_user(struct perf_regs *regs_user,
6629 struct pt_regs *regs)
6631 if (user_mode(regs)) {
6632 regs_user->abi = perf_reg_abi(current);
6633 regs_user->regs = regs;
6634 } else if (!(current->flags & PF_KTHREAD)) {
6635 perf_get_regs_user(regs_user, regs);
6637 regs_user->abi = PERF_SAMPLE_REGS_ABI_NONE;
6638 regs_user->regs = NULL;
6642 static void perf_sample_regs_intr(struct perf_regs *regs_intr,
6643 struct pt_regs *regs)
6645 regs_intr->regs = regs;
6646 regs_intr->abi = perf_reg_abi(current);
6651 * Get remaining task size from user stack pointer.
6653 * It'd be better to take stack vma map and limit this more
6654 * precisely, but there's no way to get it safely under interrupt,
6655 * so using TASK_SIZE as limit.
6657 static u64 perf_ustack_task_size(struct pt_regs *regs)
6659 unsigned long addr = perf_user_stack_pointer(regs);
6661 if (!addr || addr >= TASK_SIZE)
6664 return TASK_SIZE - addr;
6668 perf_sample_ustack_size(u16 stack_size, u16 header_size,
6669 struct pt_regs *regs)
6673 /* No regs, no stack pointer, no dump. */
6678 * Check if we fit in with the requested stack size into the:
6680 * If we don't, we limit the size to the TASK_SIZE.
6682 * - remaining sample size
6683 * If we don't, we customize the stack size to
6684 * fit in to the remaining sample size.
6687 task_size = min((u64) USHRT_MAX, perf_ustack_task_size(regs));
6688 stack_size = min(stack_size, (u16) task_size);
6690 /* Current header size plus static size and dynamic size. */
6691 header_size += 2 * sizeof(u64);
6693 /* Do we fit in with the current stack dump size? */
6694 if ((u16) (header_size + stack_size) < header_size) {
6696 * If we overflow the maximum size for the sample,
6697 * we customize the stack dump size to fit in.
6699 stack_size = USHRT_MAX - header_size - sizeof(u64);
6700 stack_size = round_up(stack_size, sizeof(u64));
6707 perf_output_sample_ustack(struct perf_output_handle *handle, u64 dump_size,
6708 struct pt_regs *regs)
6710 /* Case of a kernel thread, nothing to dump */
6713 perf_output_put(handle, size);
6723 * - the size requested by user or the best one we can fit
6724 * in to the sample max size
6726 * - user stack dump data
6728 * - the actual dumped size
6732 perf_output_put(handle, dump_size);
6735 sp = perf_user_stack_pointer(regs);
6736 fs = force_uaccess_begin();
6737 rem = __output_copy_user(handle, (void *) sp, dump_size);
6738 force_uaccess_end(fs);
6739 dyn_size = dump_size - rem;
6741 perf_output_skip(handle, rem);
6744 perf_output_put(handle, dyn_size);
6748 static unsigned long perf_prepare_sample_aux(struct perf_event *event,
6749 struct perf_sample_data *data,
6752 struct perf_event *sampler = event->aux_event;
6753 struct perf_buffer *rb;
6760 if (WARN_ON_ONCE(READ_ONCE(sampler->state) != PERF_EVENT_STATE_ACTIVE))
6763 if (WARN_ON_ONCE(READ_ONCE(sampler->oncpu) != smp_processor_id()))
6766 rb = ring_buffer_get(sampler->parent ? sampler->parent : sampler);
6771 * If this is an NMI hit inside sampling code, don't take
6772 * the sample. See also perf_aux_sample_output().
6774 if (READ_ONCE(rb->aux_in_sampling)) {
6777 size = min_t(size_t, size, perf_aux_size(rb));
6778 data->aux_size = ALIGN(size, sizeof(u64));
6780 ring_buffer_put(rb);
6783 return data->aux_size;
6786 static long perf_pmu_snapshot_aux(struct perf_buffer *rb,
6787 struct perf_event *event,
6788 struct perf_output_handle *handle,
6791 unsigned long flags;
6795 * Normal ->start()/->stop() callbacks run in IRQ mode in scheduler
6796 * paths. If we start calling them in NMI context, they may race with
6797 * the IRQ ones, that is, for example, re-starting an event that's just
6798 * been stopped, which is why we're using a separate callback that
6799 * doesn't change the event state.
6801 * IRQs need to be disabled to prevent IPIs from racing with us.
6803 local_irq_save(flags);
6805 * Guard against NMI hits inside the critical section;
6806 * see also perf_prepare_sample_aux().
6808 WRITE_ONCE(rb->aux_in_sampling, 1);
6811 ret = event->pmu->snapshot_aux(event, handle, size);
6814 WRITE_ONCE(rb->aux_in_sampling, 0);
6815 local_irq_restore(flags);
6820 static void perf_aux_sample_output(struct perf_event *event,
6821 struct perf_output_handle *handle,
6822 struct perf_sample_data *data)
6824 struct perf_event *sampler = event->aux_event;
6825 struct perf_buffer *rb;
6829 if (WARN_ON_ONCE(!sampler || !data->aux_size))
6832 rb = ring_buffer_get(sampler->parent ? sampler->parent : sampler);
6836 size = perf_pmu_snapshot_aux(rb, sampler, handle, data->aux_size);
6839 * An error here means that perf_output_copy() failed (returned a
6840 * non-zero surplus that it didn't copy), which in its current
6841 * enlightened implementation is not possible. If that changes, we'd
6844 if (WARN_ON_ONCE(size < 0))
6848 * The pad comes from ALIGN()ing data->aux_size up to u64 in
6849 * perf_prepare_sample_aux(), so should not be more than that.
6851 pad = data->aux_size - size;
6852 if (WARN_ON_ONCE(pad >= sizeof(u64)))
6857 perf_output_copy(handle, &zero, pad);
6861 ring_buffer_put(rb);
6864 static void __perf_event_header__init_id(struct perf_event_header *header,
6865 struct perf_sample_data *data,
6866 struct perf_event *event)
6868 u64 sample_type = event->attr.sample_type;
6870 data->type = sample_type;
6871 header->size += event->id_header_size;
6873 if (sample_type & PERF_SAMPLE_TID) {
6874 /* namespace issues */
6875 data->tid_entry.pid = perf_event_pid(event, current);
6876 data->tid_entry.tid = perf_event_tid(event, current);
6879 if (sample_type & PERF_SAMPLE_TIME)
6880 data->time = perf_event_clock(event);
6882 if (sample_type & (PERF_SAMPLE_ID | PERF_SAMPLE_IDENTIFIER))
6883 data->id = primary_event_id(event);
6885 if (sample_type & PERF_SAMPLE_STREAM_ID)
6886 data->stream_id = event->id;
6888 if (sample_type & PERF_SAMPLE_CPU) {
6889 data->cpu_entry.cpu = raw_smp_processor_id();
6890 data->cpu_entry.reserved = 0;
6894 void perf_event_header__init_id(struct perf_event_header *header,
6895 struct perf_sample_data *data,
6896 struct perf_event *event)
6898 if (event->attr.sample_id_all)
6899 __perf_event_header__init_id(header, data, event);
6902 static void __perf_event__output_id_sample(struct perf_output_handle *handle,
6903 struct perf_sample_data *data)
6905 u64 sample_type = data->type;
6907 if (sample_type & PERF_SAMPLE_TID)
6908 perf_output_put(handle, data->tid_entry);
6910 if (sample_type & PERF_SAMPLE_TIME)
6911 perf_output_put(handle, data->time);
6913 if (sample_type & PERF_SAMPLE_ID)
6914 perf_output_put(handle, data->id);
6916 if (sample_type & PERF_SAMPLE_STREAM_ID)
6917 perf_output_put(handle, data->stream_id);
6919 if (sample_type & PERF_SAMPLE_CPU)
6920 perf_output_put(handle, data->cpu_entry);
6922 if (sample_type & PERF_SAMPLE_IDENTIFIER)
6923 perf_output_put(handle, data->id);
6926 void perf_event__output_id_sample(struct perf_event *event,
6927 struct perf_output_handle *handle,
6928 struct perf_sample_data *sample)
6930 if (event->attr.sample_id_all)
6931 __perf_event__output_id_sample(handle, sample);
6934 static void perf_output_read_one(struct perf_output_handle *handle,
6935 struct perf_event *event,
6936 u64 enabled, u64 running)
6938 u64 read_format = event->attr.read_format;
6942 values[n++] = perf_event_count(event);
6943 if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED) {
6944 values[n++] = enabled +
6945 atomic64_read(&event->child_total_time_enabled);
6947 if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING) {
6948 values[n++] = running +
6949 atomic64_read(&event->child_total_time_running);
6951 if (read_format & PERF_FORMAT_ID)
6952 values[n++] = primary_event_id(event);
6954 __output_copy(handle, values, n * sizeof(u64));
6957 static void perf_output_read_group(struct perf_output_handle *handle,
6958 struct perf_event *event,
6959 u64 enabled, u64 running)
6961 struct perf_event *leader = event->group_leader, *sub;
6962 u64 read_format = event->attr.read_format;
6966 values[n++] = 1 + leader->nr_siblings;
6968 if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED)
6969 values[n++] = enabled;
6971 if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING)
6972 values[n++] = running;
6974 if ((leader != event) &&
6975 (leader->state == PERF_EVENT_STATE_ACTIVE))
6976 leader->pmu->read(leader);
6978 values[n++] = perf_event_count(leader);
6979 if (read_format & PERF_FORMAT_ID)
6980 values[n++] = primary_event_id(leader);
6982 __output_copy(handle, values, n * sizeof(u64));
6984 for_each_sibling_event(sub, leader) {
6987 if ((sub != event) &&
6988 (sub->state == PERF_EVENT_STATE_ACTIVE))
6989 sub->pmu->read(sub);
6991 values[n++] = perf_event_count(sub);
6992 if (read_format & PERF_FORMAT_ID)
6993 values[n++] = primary_event_id(sub);
6995 __output_copy(handle, values, n * sizeof(u64));
6999 #define PERF_FORMAT_TOTAL_TIMES (PERF_FORMAT_TOTAL_TIME_ENABLED|\
7000 PERF_FORMAT_TOTAL_TIME_RUNNING)
7003 * XXX PERF_SAMPLE_READ vs inherited events seems difficult.
7005 * The problem is that its both hard and excessively expensive to iterate the
7006 * child list, not to mention that its impossible to IPI the children running
7007 * on another CPU, from interrupt/NMI context.
7009 static void perf_output_read(struct perf_output_handle *handle,
7010 struct perf_event *event)
7012 u64 enabled = 0, running = 0, now;
7013 u64 read_format = event->attr.read_format;
7016 * compute total_time_enabled, total_time_running
7017 * based on snapshot values taken when the event
7018 * was last scheduled in.
7020 * we cannot simply called update_context_time()
7021 * because of locking issue as we are called in
7024 if (read_format & PERF_FORMAT_TOTAL_TIMES)
7025 calc_timer_values(event, &now, &enabled, &running);
7027 if (event->attr.read_format & PERF_FORMAT_GROUP)
7028 perf_output_read_group(handle, event, enabled, running);
7030 perf_output_read_one(handle, event, enabled, running);
7033 static inline bool perf_sample_save_hw_index(struct perf_event *event)
7035 return event->attr.branch_sample_type & PERF_SAMPLE_BRANCH_HW_INDEX;
7038 void perf_output_sample(struct perf_output_handle *handle,
7039 struct perf_event_header *header,
7040 struct perf_sample_data *data,
7041 struct perf_event *event)
7043 u64 sample_type = data->type;
7045 perf_output_put(handle, *header);
7047 if (sample_type & PERF_SAMPLE_IDENTIFIER)
7048 perf_output_put(handle, data->id);
7050 if (sample_type & PERF_SAMPLE_IP)
7051 perf_output_put(handle, data->ip);
7053 if (sample_type & PERF_SAMPLE_TID)
7054 perf_output_put(handle, data->tid_entry);
7056 if (sample_type & PERF_SAMPLE_TIME)
7057 perf_output_put(handle, data->time);
7059 if (sample_type & PERF_SAMPLE_ADDR)
7060 perf_output_put(handle, data->addr);
7062 if (sample_type & PERF_SAMPLE_ID)
7063 perf_output_put(handle, data->id);
7065 if (sample_type & PERF_SAMPLE_STREAM_ID)
7066 perf_output_put(handle, data->stream_id);
7068 if (sample_type & PERF_SAMPLE_CPU)
7069 perf_output_put(handle, data->cpu_entry);
7071 if (sample_type & PERF_SAMPLE_PERIOD)
7072 perf_output_put(handle, data->period);
7074 if (sample_type & PERF_SAMPLE_READ)
7075 perf_output_read(handle, event);
7077 if (sample_type & PERF_SAMPLE_CALLCHAIN) {
7080 size += data->callchain->nr;
7081 size *= sizeof(u64);
7082 __output_copy(handle, data->callchain, size);
7085 if (sample_type & PERF_SAMPLE_RAW) {
7086 struct perf_raw_record *raw = data->raw;
7089 struct perf_raw_frag *frag = &raw->frag;
7091 perf_output_put(handle, raw->size);
7094 __output_custom(handle, frag->copy,
7095 frag->data, frag->size);
7097 __output_copy(handle, frag->data,
7100 if (perf_raw_frag_last(frag))
7105 __output_skip(handle, NULL, frag->pad);
7111 .size = sizeof(u32),
7114 perf_output_put(handle, raw);
7118 if (sample_type & PERF_SAMPLE_BRANCH_STACK) {
7119 if (data->br_stack) {
7122 size = data->br_stack->nr
7123 * sizeof(struct perf_branch_entry);
7125 perf_output_put(handle, data->br_stack->nr);
7126 if (perf_sample_save_hw_index(event))
7127 perf_output_put(handle, data->br_stack->hw_idx);
7128 perf_output_copy(handle, data->br_stack->entries, size);
7131 * we always store at least the value of nr
7134 perf_output_put(handle, nr);
7138 if (sample_type & PERF_SAMPLE_REGS_USER) {
7139 u64 abi = data->regs_user.abi;
7142 * If there are no regs to dump, notice it through
7143 * first u64 being zero (PERF_SAMPLE_REGS_ABI_NONE).
7145 perf_output_put(handle, abi);
7148 u64 mask = event->attr.sample_regs_user;
7149 perf_output_sample_regs(handle,
7150 data->regs_user.regs,
7155 if (sample_type & PERF_SAMPLE_STACK_USER) {
7156 perf_output_sample_ustack(handle,
7157 data->stack_user_size,
7158 data->regs_user.regs);
7161 if (sample_type & PERF_SAMPLE_WEIGHT_TYPE)
7162 perf_output_put(handle, data->weight.full);
7164 if (sample_type & PERF_SAMPLE_DATA_SRC)
7165 perf_output_put(handle, data->data_src.val);
7167 if (sample_type & PERF_SAMPLE_TRANSACTION)
7168 perf_output_put(handle, data->txn);
7170 if (sample_type & PERF_SAMPLE_REGS_INTR) {
7171 u64 abi = data->regs_intr.abi;
7173 * If there are no regs to dump, notice it through
7174 * first u64 being zero (PERF_SAMPLE_REGS_ABI_NONE).
7176 perf_output_put(handle, abi);
7179 u64 mask = event->attr.sample_regs_intr;
7181 perf_output_sample_regs(handle,
7182 data->regs_intr.regs,
7187 if (sample_type & PERF_SAMPLE_PHYS_ADDR)
7188 perf_output_put(handle, data->phys_addr);
7190 if (sample_type & PERF_SAMPLE_CGROUP)
7191 perf_output_put(handle, data->cgroup);
7193 if (sample_type & PERF_SAMPLE_DATA_PAGE_SIZE)
7194 perf_output_put(handle, data->data_page_size);
7196 if (sample_type & PERF_SAMPLE_CODE_PAGE_SIZE)
7197 perf_output_put(handle, data->code_page_size);
7199 if (sample_type & PERF_SAMPLE_AUX) {
7200 perf_output_put(handle, data->aux_size);
7203 perf_aux_sample_output(event, handle, data);
7206 if (!event->attr.watermark) {
7207 int wakeup_events = event->attr.wakeup_events;
7209 if (wakeup_events) {
7210 struct perf_buffer *rb = handle->rb;
7211 int events = local_inc_return(&rb->events);
7213 if (events >= wakeup_events) {
7214 local_sub(wakeup_events, &rb->events);
7215 local_inc(&rb->wakeup);
7221 static u64 perf_virt_to_phys(u64 virt)
7228 if (virt >= TASK_SIZE) {
7229 /* If it's vmalloc()d memory, leave phys_addr as 0 */
7230 if (virt_addr_valid((void *)(uintptr_t)virt) &&
7231 !(virt >= VMALLOC_START && virt < VMALLOC_END))
7232 phys_addr = (u64)virt_to_phys((void *)(uintptr_t)virt);
7235 * Walking the pages tables for user address.
7236 * Interrupts are disabled, so it prevents any tear down
7237 * of the page tables.
7238 * Try IRQ-safe get_user_page_fast_only first.
7239 * If failed, leave phys_addr as 0.
7241 if (current->mm != NULL) {
7244 pagefault_disable();
7245 if (get_user_page_fast_only(virt, 0, &p)) {
7246 phys_addr = page_to_phys(p) + virt % PAGE_SIZE;
7257 * Return the pagetable size of a given virtual address.
7259 static u64 perf_get_pgtable_size(struct mm_struct *mm, unsigned long addr)
7263 #ifdef CONFIG_HAVE_FAST_GUP
7270 pgdp = pgd_offset(mm, addr);
7271 pgd = READ_ONCE(*pgdp);
7276 return pgd_leaf_size(pgd);
7278 p4dp = p4d_offset_lockless(pgdp, pgd, addr);
7279 p4d = READ_ONCE(*p4dp);
7280 if (!p4d_present(p4d))
7284 return p4d_leaf_size(p4d);
7286 pudp = pud_offset_lockless(p4dp, p4d, addr);
7287 pud = READ_ONCE(*pudp);
7288 if (!pud_present(pud))
7292 return pud_leaf_size(pud);
7294 pmdp = pmd_offset_lockless(pudp, pud, addr);
7295 pmd = READ_ONCE(*pmdp);
7296 if (!pmd_present(pmd))
7300 return pmd_leaf_size(pmd);
7302 ptep = pte_offset_map(&pmd, addr);
7303 pte = ptep_get_lockless(ptep);
7304 if (pte_present(pte))
7305 size = pte_leaf_size(pte);
7307 #endif /* CONFIG_HAVE_FAST_GUP */
7312 static u64 perf_get_page_size(unsigned long addr)
7314 struct mm_struct *mm;
7315 unsigned long flags;
7322 * Software page-table walkers must disable IRQs,
7323 * which prevents any tear down of the page tables.
7325 local_irq_save(flags);
7330 * For kernel threads and the like, use init_mm so that
7331 * we can find kernel memory.
7336 size = perf_get_pgtable_size(mm, addr);
7338 local_irq_restore(flags);
7343 static struct perf_callchain_entry __empty_callchain = { .nr = 0, };
7345 struct perf_callchain_entry *
7346 perf_callchain(struct perf_event *event, struct pt_regs *regs)
7348 bool kernel = !event->attr.exclude_callchain_kernel;
7349 bool user = !event->attr.exclude_callchain_user;
7350 /* Disallow cross-task user callchains. */
7351 bool crosstask = event->ctx->task && event->ctx->task != current;
7352 const u32 max_stack = event->attr.sample_max_stack;
7353 struct perf_callchain_entry *callchain;
7355 if (!kernel && !user)
7356 return &__empty_callchain;
7358 callchain = get_perf_callchain(regs, 0, kernel, user,
7359 max_stack, crosstask, true);
7360 return callchain ?: &__empty_callchain;
7363 void perf_prepare_sample(struct perf_event_header *header,
7364 struct perf_sample_data *data,
7365 struct perf_event *event,
7366 struct pt_regs *regs)
7368 u64 sample_type = event->attr.sample_type;
7370 header->type = PERF_RECORD_SAMPLE;
7371 header->size = sizeof(*header) + event->header_size;
7374 header->misc |= perf_misc_flags(regs);
7376 __perf_event_header__init_id(header, data, event);
7378 if (sample_type & (PERF_SAMPLE_IP | PERF_SAMPLE_CODE_PAGE_SIZE))
7379 data->ip = perf_instruction_pointer(regs);
7381 if (sample_type & PERF_SAMPLE_CALLCHAIN) {
7384 if (!(sample_type & __PERF_SAMPLE_CALLCHAIN_EARLY))
7385 data->callchain = perf_callchain(event, regs);
7387 size += data->callchain->nr;
7389 header->size += size * sizeof(u64);
7392 if (sample_type & PERF_SAMPLE_RAW) {
7393 struct perf_raw_record *raw = data->raw;
7397 struct perf_raw_frag *frag = &raw->frag;
7402 if (perf_raw_frag_last(frag))
7407 size = round_up(sum + sizeof(u32), sizeof(u64));
7408 raw->size = size - sizeof(u32);
7409 frag->pad = raw->size - sum;
7414 header->size += size;
7417 if (sample_type & PERF_SAMPLE_BRANCH_STACK) {
7418 int size = sizeof(u64); /* nr */
7419 if (data->br_stack) {
7420 if (perf_sample_save_hw_index(event))
7421 size += sizeof(u64);
7423 size += data->br_stack->nr
7424 * sizeof(struct perf_branch_entry);
7426 header->size += size;
7429 if (sample_type & (PERF_SAMPLE_REGS_USER | PERF_SAMPLE_STACK_USER))
7430 perf_sample_regs_user(&data->regs_user, regs);
7432 if (sample_type & PERF_SAMPLE_REGS_USER) {
7433 /* regs dump ABI info */
7434 int size = sizeof(u64);
7436 if (data->regs_user.regs) {
7437 u64 mask = event->attr.sample_regs_user;
7438 size += hweight64(mask) * sizeof(u64);
7441 header->size += size;
7444 if (sample_type & PERF_SAMPLE_STACK_USER) {
7446 * Either we need PERF_SAMPLE_STACK_USER bit to be always
7447 * processed as the last one or have additional check added
7448 * in case new sample type is added, because we could eat
7449 * up the rest of the sample size.
7451 u16 stack_size = event->attr.sample_stack_user;
7452 u16 size = sizeof(u64);
7454 stack_size = perf_sample_ustack_size(stack_size, header->size,
7455 data->regs_user.regs);
7458 * If there is something to dump, add space for the dump
7459 * itself and for the field that tells the dynamic size,
7460 * which is how many have been actually dumped.
7463 size += sizeof(u64) + stack_size;
7465 data->stack_user_size = stack_size;
7466 header->size += size;
7469 if (sample_type & PERF_SAMPLE_REGS_INTR) {
7470 /* regs dump ABI info */
7471 int size = sizeof(u64);
7473 perf_sample_regs_intr(&data->regs_intr, regs);
7475 if (data->regs_intr.regs) {
7476 u64 mask = event->attr.sample_regs_intr;
7478 size += hweight64(mask) * sizeof(u64);
7481 header->size += size;
7484 if (sample_type & PERF_SAMPLE_PHYS_ADDR)
7485 data->phys_addr = perf_virt_to_phys(data->addr);
7487 #ifdef CONFIG_CGROUP_PERF
7488 if (sample_type & PERF_SAMPLE_CGROUP) {
7489 struct cgroup *cgrp;
7491 /* protected by RCU */
7492 cgrp = task_css_check(current, perf_event_cgrp_id, 1)->cgroup;
7493 data->cgroup = cgroup_id(cgrp);
7498 * PERF_DATA_PAGE_SIZE requires PERF_SAMPLE_ADDR. If the user doesn't
7499 * require PERF_SAMPLE_ADDR, kernel implicitly retrieve the data->addr,
7500 * but the value will not dump to the userspace.
7502 if (sample_type & PERF_SAMPLE_DATA_PAGE_SIZE)
7503 data->data_page_size = perf_get_page_size(data->addr);
7505 if (sample_type & PERF_SAMPLE_CODE_PAGE_SIZE)
7506 data->code_page_size = perf_get_page_size(data->ip);
7508 if (sample_type & PERF_SAMPLE_AUX) {
7511 header->size += sizeof(u64); /* size */
7514 * Given the 16bit nature of header::size, an AUX sample can
7515 * easily overflow it, what with all the preceding sample bits.
7516 * Make sure this doesn't happen by using up to U16_MAX bytes
7517 * per sample in total (rounded down to 8 byte boundary).
7519 size = min_t(size_t, U16_MAX - header->size,
7520 event->attr.aux_sample_size);
7521 size = rounddown(size, 8);
7522 size = perf_prepare_sample_aux(event, data, size);
7524 WARN_ON_ONCE(size + header->size > U16_MAX);
7525 header->size += size;
7528 * If you're adding more sample types here, you likely need to do
7529 * something about the overflowing header::size, like repurpose the
7530 * lowest 3 bits of size, which should be always zero at the moment.
7531 * This raises a more important question, do we really need 512k sized
7532 * samples and why, so good argumentation is in order for whatever you
7535 WARN_ON_ONCE(header->size & 7);
7538 static __always_inline int
7539 __perf_event_output(struct perf_event *event,
7540 struct perf_sample_data *data,
7541 struct pt_regs *regs,
7542 int (*output_begin)(struct perf_output_handle *,
7543 struct perf_sample_data *,
7544 struct perf_event *,
7547 struct perf_output_handle handle;
7548 struct perf_event_header header;
7551 /* protect the callchain buffers */
7554 perf_prepare_sample(&header, data, event, regs);
7556 err = output_begin(&handle, data, event, header.size);
7560 perf_output_sample(&handle, &header, data, event);
7562 perf_output_end(&handle);
7570 perf_event_output_forward(struct perf_event *event,
7571 struct perf_sample_data *data,
7572 struct pt_regs *regs)
7574 __perf_event_output(event, data, regs, perf_output_begin_forward);
7578 perf_event_output_backward(struct perf_event *event,
7579 struct perf_sample_data *data,
7580 struct pt_regs *regs)
7582 __perf_event_output(event, data, regs, perf_output_begin_backward);
7586 perf_event_output(struct perf_event *event,
7587 struct perf_sample_data *data,
7588 struct pt_regs *regs)
7590 return __perf_event_output(event, data, regs, perf_output_begin);
7597 struct perf_read_event {
7598 struct perf_event_header header;
7605 perf_event_read_event(struct perf_event *event,
7606 struct task_struct *task)
7608 struct perf_output_handle handle;
7609 struct perf_sample_data sample;
7610 struct perf_read_event read_event = {
7612 .type = PERF_RECORD_READ,
7614 .size = sizeof(read_event) + event->read_size,
7616 .pid = perf_event_pid(event, task),
7617 .tid = perf_event_tid(event, task),
7621 perf_event_header__init_id(&read_event.header, &sample, event);
7622 ret = perf_output_begin(&handle, &sample, event, read_event.header.size);
7626 perf_output_put(&handle, read_event);
7627 perf_output_read(&handle, event);
7628 perf_event__output_id_sample(event, &handle, &sample);
7630 perf_output_end(&handle);
7633 typedef void (perf_iterate_f)(struct perf_event *event, void *data);
7636 perf_iterate_ctx(struct perf_event_context *ctx,
7637 perf_iterate_f output,
7638 void *data, bool all)
7640 struct perf_event *event;
7642 list_for_each_entry_rcu(event, &ctx->event_list, event_entry) {
7644 if (event->state < PERF_EVENT_STATE_INACTIVE)
7646 if (!event_filter_match(event))
7650 output(event, data);
7654 static void perf_iterate_sb_cpu(perf_iterate_f output, void *data)
7656 struct pmu_event_list *pel = this_cpu_ptr(&pmu_sb_events);
7657 struct perf_event *event;
7659 list_for_each_entry_rcu(event, &pel->list, sb_list) {
7661 * Skip events that are not fully formed yet; ensure that
7662 * if we observe event->ctx, both event and ctx will be
7663 * complete enough. See perf_install_in_context().
7665 if (!smp_load_acquire(&event->ctx))
7668 if (event->state < PERF_EVENT_STATE_INACTIVE)
7670 if (!event_filter_match(event))
7672 output(event, data);
7677 * Iterate all events that need to receive side-band events.
7679 * For new callers; ensure that account_pmu_sb_event() includes
7680 * your event, otherwise it might not get delivered.
7683 perf_iterate_sb(perf_iterate_f output, void *data,
7684 struct perf_event_context *task_ctx)
7686 struct perf_event_context *ctx;
7693 * If we have task_ctx != NULL we only notify the task context itself.
7694 * The task_ctx is set only for EXIT events before releasing task
7698 perf_iterate_ctx(task_ctx, output, data, false);
7702 perf_iterate_sb_cpu(output, data);
7704 for_each_task_context_nr(ctxn) {
7705 ctx = rcu_dereference(current->perf_event_ctxp[ctxn]);
7707 perf_iterate_ctx(ctx, output, data, false);
7715 * Clear all file-based filters at exec, they'll have to be
7716 * re-instated when/if these objects are mmapped again.
7718 static void perf_event_addr_filters_exec(struct perf_event *event, void *data)
7720 struct perf_addr_filters_head *ifh = perf_event_addr_filters(event);
7721 struct perf_addr_filter *filter;
7722 unsigned int restart = 0, count = 0;
7723 unsigned long flags;
7725 if (!has_addr_filter(event))
7728 raw_spin_lock_irqsave(&ifh->lock, flags);
7729 list_for_each_entry(filter, &ifh->list, entry) {
7730 if (filter->path.dentry) {
7731 event->addr_filter_ranges[count].start = 0;
7732 event->addr_filter_ranges[count].size = 0;
7740 event->addr_filters_gen++;
7741 raw_spin_unlock_irqrestore(&ifh->lock, flags);
7744 perf_event_stop(event, 1);
7747 void perf_event_exec(void)
7749 struct perf_event_context *ctx;
7752 for_each_task_context_nr(ctxn) {
7753 perf_event_enable_on_exec(ctxn);
7754 perf_event_remove_on_exec(ctxn);
7757 ctx = rcu_dereference(current->perf_event_ctxp[ctxn]);
7759 perf_iterate_ctx(ctx, perf_event_addr_filters_exec,
7766 struct remote_output {
7767 struct perf_buffer *rb;
7771 static void __perf_event_output_stop(struct perf_event *event, void *data)
7773 struct perf_event *parent = event->parent;
7774 struct remote_output *ro = data;
7775 struct perf_buffer *rb = ro->rb;
7776 struct stop_event_data sd = {
7780 if (!has_aux(event))
7787 * In case of inheritance, it will be the parent that links to the
7788 * ring-buffer, but it will be the child that's actually using it.
7790 * We are using event::rb to determine if the event should be stopped,
7791 * however this may race with ring_buffer_attach() (through set_output),
7792 * which will make us skip the event that actually needs to be stopped.
7793 * So ring_buffer_attach() has to stop an aux event before re-assigning
7796 if (rcu_dereference(parent->rb) == rb)
7797 ro->err = __perf_event_stop(&sd);
7800 static int __perf_pmu_output_stop(void *info)
7802 struct perf_event *event = info;
7803 struct pmu *pmu = event->ctx->pmu;
7804 struct perf_cpu_context *cpuctx = this_cpu_ptr(pmu->pmu_cpu_context);
7805 struct remote_output ro = {
7810 perf_iterate_ctx(&cpuctx->ctx, __perf_event_output_stop, &ro, false);
7811 if (cpuctx->task_ctx)
7812 perf_iterate_ctx(cpuctx->task_ctx, __perf_event_output_stop,
7819 static void perf_pmu_output_stop(struct perf_event *event)
7821 struct perf_event *iter;
7826 list_for_each_entry_rcu(iter, &event->rb->event_list, rb_entry) {
7828 * For per-CPU events, we need to make sure that neither they
7829 * nor their children are running; for cpu==-1 events it's
7830 * sufficient to stop the event itself if it's active, since
7831 * it can't have children.
7835 cpu = READ_ONCE(iter->oncpu);
7840 err = cpu_function_call(cpu, __perf_pmu_output_stop, event);
7841 if (err == -EAGAIN) {
7850 * task tracking -- fork/exit
7852 * enabled by: attr.comm | attr.mmap | attr.mmap2 | attr.mmap_data | attr.task
7855 struct perf_task_event {
7856 struct task_struct *task;
7857 struct perf_event_context *task_ctx;
7860 struct perf_event_header header;
7870 static int perf_event_task_match(struct perf_event *event)
7872 return event->attr.comm || event->attr.mmap ||
7873 event->attr.mmap2 || event->attr.mmap_data ||
7877 static void perf_event_task_output(struct perf_event *event,
7880 struct perf_task_event *task_event = data;
7881 struct perf_output_handle handle;
7882 struct perf_sample_data sample;
7883 struct task_struct *task = task_event->task;
7884 int ret, size = task_event->event_id.header.size;
7886 if (!perf_event_task_match(event))
7889 perf_event_header__init_id(&task_event->event_id.header, &sample, event);
7891 ret = perf_output_begin(&handle, &sample, event,
7892 task_event->event_id.header.size);
7896 task_event->event_id.pid = perf_event_pid(event, task);
7897 task_event->event_id.tid = perf_event_tid(event, task);
7899 if (task_event->event_id.header.type == PERF_RECORD_EXIT) {
7900 task_event->event_id.ppid = perf_event_pid(event,
7902 task_event->event_id.ptid = perf_event_pid(event,
7904 } else { /* PERF_RECORD_FORK */
7905 task_event->event_id.ppid = perf_event_pid(event, current);
7906 task_event->event_id.ptid = perf_event_tid(event, current);
7909 task_event->event_id.time = perf_event_clock(event);
7911 perf_output_put(&handle, task_event->event_id);
7913 perf_event__output_id_sample(event, &handle, &sample);
7915 perf_output_end(&handle);
7917 task_event->event_id.header.size = size;
7920 static void perf_event_task(struct task_struct *task,
7921 struct perf_event_context *task_ctx,
7924 struct perf_task_event task_event;
7926 if (!atomic_read(&nr_comm_events) &&
7927 !atomic_read(&nr_mmap_events) &&
7928 !atomic_read(&nr_task_events))
7931 task_event = (struct perf_task_event){
7933 .task_ctx = task_ctx,
7936 .type = new ? PERF_RECORD_FORK : PERF_RECORD_EXIT,
7938 .size = sizeof(task_event.event_id),
7948 perf_iterate_sb(perf_event_task_output,
7953 void perf_event_fork(struct task_struct *task)
7955 perf_event_task(task, NULL, 1);
7956 perf_event_namespaces(task);
7963 struct perf_comm_event {
7964 struct task_struct *task;
7969 struct perf_event_header header;
7976 static int perf_event_comm_match(struct perf_event *event)
7978 return event->attr.comm;
7981 static void perf_event_comm_output(struct perf_event *event,
7984 struct perf_comm_event *comm_event = data;
7985 struct perf_output_handle handle;
7986 struct perf_sample_data sample;
7987 int size = comm_event->event_id.header.size;
7990 if (!perf_event_comm_match(event))
7993 perf_event_header__init_id(&comm_event->event_id.header, &sample, event);
7994 ret = perf_output_begin(&handle, &sample, event,
7995 comm_event->event_id.header.size);
8000 comm_event->event_id.pid = perf_event_pid(event, comm_event->task);
8001 comm_event->event_id.tid = perf_event_tid(event, comm_event->task);
8003 perf_output_put(&handle, comm_event->event_id);
8004 __output_copy(&handle, comm_event->comm,
8005 comm_event->comm_size);
8007 perf_event__output_id_sample(event, &handle, &sample);
8009 perf_output_end(&handle);
8011 comm_event->event_id.header.size = size;
8014 static void perf_event_comm_event(struct perf_comm_event *comm_event)
8016 char comm[TASK_COMM_LEN];
8019 memset(comm, 0, sizeof(comm));
8020 strlcpy(comm, comm_event->task->comm, sizeof(comm));
8021 size = ALIGN(strlen(comm)+1, sizeof(u64));
8023 comm_event->comm = comm;
8024 comm_event->comm_size = size;
8026 comm_event->event_id.header.size = sizeof(comm_event->event_id) + size;
8028 perf_iterate_sb(perf_event_comm_output,
8033 void perf_event_comm(struct task_struct *task, bool exec)
8035 struct perf_comm_event comm_event;
8037 if (!atomic_read(&nr_comm_events))
8040 comm_event = (struct perf_comm_event){
8046 .type = PERF_RECORD_COMM,
8047 .misc = exec ? PERF_RECORD_MISC_COMM_EXEC : 0,
8055 perf_event_comm_event(&comm_event);
8059 * namespaces tracking
8062 struct perf_namespaces_event {
8063 struct task_struct *task;
8066 struct perf_event_header header;
8071 struct perf_ns_link_info link_info[NR_NAMESPACES];
8075 static int perf_event_namespaces_match(struct perf_event *event)
8077 return event->attr.namespaces;
8080 static void perf_event_namespaces_output(struct perf_event *event,
8083 struct perf_namespaces_event *namespaces_event = data;
8084 struct perf_output_handle handle;
8085 struct perf_sample_data sample;
8086 u16 header_size = namespaces_event->event_id.header.size;
8089 if (!perf_event_namespaces_match(event))
8092 perf_event_header__init_id(&namespaces_event->event_id.header,
8094 ret = perf_output_begin(&handle, &sample, event,
8095 namespaces_event->event_id.header.size);
8099 namespaces_event->event_id.pid = perf_event_pid(event,
8100 namespaces_event->task);
8101 namespaces_event->event_id.tid = perf_event_tid(event,
8102 namespaces_event->task);
8104 perf_output_put(&handle, namespaces_event->event_id);
8106 perf_event__output_id_sample(event, &handle, &sample);
8108 perf_output_end(&handle);
8110 namespaces_event->event_id.header.size = header_size;
8113 static void perf_fill_ns_link_info(struct perf_ns_link_info *ns_link_info,
8114 struct task_struct *task,
8115 const struct proc_ns_operations *ns_ops)
8117 struct path ns_path;
8118 struct inode *ns_inode;
8121 error = ns_get_path(&ns_path, task, ns_ops);
8123 ns_inode = ns_path.dentry->d_inode;
8124 ns_link_info->dev = new_encode_dev(ns_inode->i_sb->s_dev);
8125 ns_link_info->ino = ns_inode->i_ino;
8130 void perf_event_namespaces(struct task_struct *task)
8132 struct perf_namespaces_event namespaces_event;
8133 struct perf_ns_link_info *ns_link_info;
8135 if (!atomic_read(&nr_namespaces_events))
8138 namespaces_event = (struct perf_namespaces_event){
8142 .type = PERF_RECORD_NAMESPACES,
8144 .size = sizeof(namespaces_event.event_id),
8148 .nr_namespaces = NR_NAMESPACES,
8149 /* .link_info[NR_NAMESPACES] */
8153 ns_link_info = namespaces_event.event_id.link_info;
8155 perf_fill_ns_link_info(&ns_link_info[MNT_NS_INDEX],
8156 task, &mntns_operations);
8158 #ifdef CONFIG_USER_NS
8159 perf_fill_ns_link_info(&ns_link_info[USER_NS_INDEX],
8160 task, &userns_operations);
8162 #ifdef CONFIG_NET_NS
8163 perf_fill_ns_link_info(&ns_link_info[NET_NS_INDEX],
8164 task, &netns_operations);
8166 #ifdef CONFIG_UTS_NS
8167 perf_fill_ns_link_info(&ns_link_info[UTS_NS_INDEX],
8168 task, &utsns_operations);
8170 #ifdef CONFIG_IPC_NS
8171 perf_fill_ns_link_info(&ns_link_info[IPC_NS_INDEX],
8172 task, &ipcns_operations);
8174 #ifdef CONFIG_PID_NS
8175 perf_fill_ns_link_info(&ns_link_info[PID_NS_INDEX],
8176 task, &pidns_operations);
8178 #ifdef CONFIG_CGROUPS
8179 perf_fill_ns_link_info(&ns_link_info[CGROUP_NS_INDEX],
8180 task, &cgroupns_operations);
8183 perf_iterate_sb(perf_event_namespaces_output,
8191 #ifdef CONFIG_CGROUP_PERF
8193 struct perf_cgroup_event {
8197 struct perf_event_header header;
8203 static int perf_event_cgroup_match(struct perf_event *event)
8205 return event->attr.cgroup;
8208 static void perf_event_cgroup_output(struct perf_event *event, void *data)
8210 struct perf_cgroup_event *cgroup_event = data;
8211 struct perf_output_handle handle;
8212 struct perf_sample_data sample;
8213 u16 header_size = cgroup_event->event_id.header.size;
8216 if (!perf_event_cgroup_match(event))
8219 perf_event_header__init_id(&cgroup_event->event_id.header,
8221 ret = perf_output_begin(&handle, &sample, event,
8222 cgroup_event->event_id.header.size);
8226 perf_output_put(&handle, cgroup_event->event_id);
8227 __output_copy(&handle, cgroup_event->path, cgroup_event->path_size);
8229 perf_event__output_id_sample(event, &handle, &sample);
8231 perf_output_end(&handle);
8233 cgroup_event->event_id.header.size = header_size;
8236 static void perf_event_cgroup(struct cgroup *cgrp)
8238 struct perf_cgroup_event cgroup_event;
8239 char path_enomem[16] = "//enomem";
8243 if (!atomic_read(&nr_cgroup_events))
8246 cgroup_event = (struct perf_cgroup_event){
8249 .type = PERF_RECORD_CGROUP,
8251 .size = sizeof(cgroup_event.event_id),
8253 .id = cgroup_id(cgrp),
8257 pathname = kmalloc(PATH_MAX, GFP_KERNEL);
8258 if (pathname == NULL) {
8259 cgroup_event.path = path_enomem;
8261 /* just to be sure to have enough space for alignment */
8262 cgroup_path(cgrp, pathname, PATH_MAX - sizeof(u64));
8263 cgroup_event.path = pathname;
8267 * Since our buffer works in 8 byte units we need to align our string
8268 * size to a multiple of 8. However, we must guarantee the tail end is
8269 * zero'd out to avoid leaking random bits to userspace.
8271 size = strlen(cgroup_event.path) + 1;
8272 while (!IS_ALIGNED(size, sizeof(u64)))
8273 cgroup_event.path[size++] = '\0';
8275 cgroup_event.event_id.header.size += size;
8276 cgroup_event.path_size = size;
8278 perf_iterate_sb(perf_event_cgroup_output,
8291 struct perf_mmap_event {
8292 struct vm_area_struct *vma;
8294 const char *file_name;
8300 u8 build_id[BUILD_ID_SIZE_MAX];
8304 struct perf_event_header header;
8314 static int perf_event_mmap_match(struct perf_event *event,
8317 struct perf_mmap_event *mmap_event = data;
8318 struct vm_area_struct *vma = mmap_event->vma;
8319 int executable = vma->vm_flags & VM_EXEC;
8321 return (!executable && event->attr.mmap_data) ||
8322 (executable && (event->attr.mmap || event->attr.mmap2));
8325 static void perf_event_mmap_output(struct perf_event *event,
8328 struct perf_mmap_event *mmap_event = data;
8329 struct perf_output_handle handle;
8330 struct perf_sample_data sample;
8331 int size = mmap_event->event_id.header.size;
8332 u32 type = mmap_event->event_id.header.type;
8336 if (!perf_event_mmap_match(event, data))
8339 if (event->attr.mmap2) {
8340 mmap_event->event_id.header.type = PERF_RECORD_MMAP2;
8341 mmap_event->event_id.header.size += sizeof(mmap_event->maj);
8342 mmap_event->event_id.header.size += sizeof(mmap_event->min);
8343 mmap_event->event_id.header.size += sizeof(mmap_event->ino);
8344 mmap_event->event_id.header.size += sizeof(mmap_event->ino_generation);
8345 mmap_event->event_id.header.size += sizeof(mmap_event->prot);
8346 mmap_event->event_id.header.size += sizeof(mmap_event->flags);
8349 perf_event_header__init_id(&mmap_event->event_id.header, &sample, event);
8350 ret = perf_output_begin(&handle, &sample, event,
8351 mmap_event->event_id.header.size);
8355 mmap_event->event_id.pid = perf_event_pid(event, current);
8356 mmap_event->event_id.tid = perf_event_tid(event, current);
8358 use_build_id = event->attr.build_id && mmap_event->build_id_size;
8360 if (event->attr.mmap2 && use_build_id)
8361 mmap_event->event_id.header.misc |= PERF_RECORD_MISC_MMAP_BUILD_ID;
8363 perf_output_put(&handle, mmap_event->event_id);
8365 if (event->attr.mmap2) {
8367 u8 size[4] = { (u8) mmap_event->build_id_size, 0, 0, 0 };
8369 __output_copy(&handle, size, 4);
8370 __output_copy(&handle, mmap_event->build_id, BUILD_ID_SIZE_MAX);
8372 perf_output_put(&handle, mmap_event->maj);
8373 perf_output_put(&handle, mmap_event->min);
8374 perf_output_put(&handle, mmap_event->ino);
8375 perf_output_put(&handle, mmap_event->ino_generation);
8377 perf_output_put(&handle, mmap_event->prot);
8378 perf_output_put(&handle, mmap_event->flags);
8381 __output_copy(&handle, mmap_event->file_name,
8382 mmap_event->file_size);
8384 perf_event__output_id_sample(event, &handle, &sample);
8386 perf_output_end(&handle);
8388 mmap_event->event_id.header.size = size;
8389 mmap_event->event_id.header.type = type;
8392 static void perf_event_mmap_event(struct perf_mmap_event *mmap_event)
8394 struct vm_area_struct *vma = mmap_event->vma;
8395 struct file *file = vma->vm_file;
8396 int maj = 0, min = 0;
8397 u64 ino = 0, gen = 0;
8398 u32 prot = 0, flags = 0;
8404 if (vma->vm_flags & VM_READ)
8406 if (vma->vm_flags & VM_WRITE)
8408 if (vma->vm_flags & VM_EXEC)
8411 if (vma->vm_flags & VM_MAYSHARE)
8414 flags = MAP_PRIVATE;
8416 if (vma->vm_flags & VM_LOCKED)
8417 flags |= MAP_LOCKED;
8418 if (is_vm_hugetlb_page(vma))
8419 flags |= MAP_HUGETLB;
8422 struct inode *inode;
8425 buf = kmalloc(PATH_MAX, GFP_KERNEL);
8431 * d_path() works from the end of the rb backwards, so we
8432 * need to add enough zero bytes after the string to handle
8433 * the 64bit alignment we do later.
8435 name = file_path(file, buf, PATH_MAX - sizeof(u64));
8440 inode = file_inode(vma->vm_file);
8441 dev = inode->i_sb->s_dev;
8443 gen = inode->i_generation;
8449 if (vma->vm_ops && vma->vm_ops->name) {
8450 name = (char *) vma->vm_ops->name(vma);
8455 name = (char *)arch_vma_name(vma);
8459 if (vma->vm_start <= vma->vm_mm->start_brk &&
8460 vma->vm_end >= vma->vm_mm->brk) {
8464 if (vma->vm_start <= vma->vm_mm->start_stack &&
8465 vma->vm_end >= vma->vm_mm->start_stack) {
8475 strlcpy(tmp, name, sizeof(tmp));
8479 * Since our buffer works in 8 byte units we need to align our string
8480 * size to a multiple of 8. However, we must guarantee the tail end is
8481 * zero'd out to avoid leaking random bits to userspace.
8483 size = strlen(name)+1;
8484 while (!IS_ALIGNED(size, sizeof(u64)))
8485 name[size++] = '\0';
8487 mmap_event->file_name = name;
8488 mmap_event->file_size = size;
8489 mmap_event->maj = maj;
8490 mmap_event->min = min;
8491 mmap_event->ino = ino;
8492 mmap_event->ino_generation = gen;
8493 mmap_event->prot = prot;
8494 mmap_event->flags = flags;
8496 if (!(vma->vm_flags & VM_EXEC))
8497 mmap_event->event_id.header.misc |= PERF_RECORD_MISC_MMAP_DATA;
8499 mmap_event->event_id.header.size = sizeof(mmap_event->event_id) + size;
8501 if (atomic_read(&nr_build_id_events))
8502 build_id_parse(vma, mmap_event->build_id, &mmap_event->build_id_size);
8504 perf_iterate_sb(perf_event_mmap_output,
8512 * Check whether inode and address range match filter criteria.
8514 static bool perf_addr_filter_match(struct perf_addr_filter *filter,
8515 struct file *file, unsigned long offset,
8518 /* d_inode(NULL) won't be equal to any mapped user-space file */
8519 if (!filter->path.dentry)
8522 if (d_inode(filter->path.dentry) != file_inode(file))
8525 if (filter->offset > offset + size)
8528 if (filter->offset + filter->size < offset)
8534 static bool perf_addr_filter_vma_adjust(struct perf_addr_filter *filter,
8535 struct vm_area_struct *vma,
8536 struct perf_addr_filter_range *fr)
8538 unsigned long vma_size = vma->vm_end - vma->vm_start;
8539 unsigned long off = vma->vm_pgoff << PAGE_SHIFT;
8540 struct file *file = vma->vm_file;
8542 if (!perf_addr_filter_match(filter, file, off, vma_size))
8545 if (filter->offset < off) {
8546 fr->start = vma->vm_start;
8547 fr->size = min(vma_size, filter->size - (off - filter->offset));
8549 fr->start = vma->vm_start + filter->offset - off;
8550 fr->size = min(vma->vm_end - fr->start, filter->size);
8556 static void __perf_addr_filters_adjust(struct perf_event *event, void *data)
8558 struct perf_addr_filters_head *ifh = perf_event_addr_filters(event);
8559 struct vm_area_struct *vma = data;
8560 struct perf_addr_filter *filter;
8561 unsigned int restart = 0, count = 0;
8562 unsigned long flags;
8564 if (!has_addr_filter(event))
8570 raw_spin_lock_irqsave(&ifh->lock, flags);
8571 list_for_each_entry(filter, &ifh->list, entry) {
8572 if (perf_addr_filter_vma_adjust(filter, vma,
8573 &event->addr_filter_ranges[count]))
8580 event->addr_filters_gen++;
8581 raw_spin_unlock_irqrestore(&ifh->lock, flags);
8584 perf_event_stop(event, 1);
8588 * Adjust all task's events' filters to the new vma
8590 static void perf_addr_filters_adjust(struct vm_area_struct *vma)
8592 struct perf_event_context *ctx;
8596 * Data tracing isn't supported yet and as such there is no need
8597 * to keep track of anything that isn't related to executable code:
8599 if (!(vma->vm_flags & VM_EXEC))
8603 for_each_task_context_nr(ctxn) {
8604 ctx = rcu_dereference(current->perf_event_ctxp[ctxn]);
8608 perf_iterate_ctx(ctx, __perf_addr_filters_adjust, vma, true);
8613 void perf_event_mmap(struct vm_area_struct *vma)
8615 struct perf_mmap_event mmap_event;
8617 if (!atomic_read(&nr_mmap_events))
8620 mmap_event = (struct perf_mmap_event){
8626 .type = PERF_RECORD_MMAP,
8627 .misc = PERF_RECORD_MISC_USER,
8632 .start = vma->vm_start,
8633 .len = vma->vm_end - vma->vm_start,
8634 .pgoff = (u64)vma->vm_pgoff << PAGE_SHIFT,
8636 /* .maj (attr_mmap2 only) */
8637 /* .min (attr_mmap2 only) */
8638 /* .ino (attr_mmap2 only) */
8639 /* .ino_generation (attr_mmap2 only) */
8640 /* .prot (attr_mmap2 only) */
8641 /* .flags (attr_mmap2 only) */
8644 perf_addr_filters_adjust(vma);
8645 perf_event_mmap_event(&mmap_event);
8648 void perf_event_aux_event(struct perf_event *event, unsigned long head,
8649 unsigned long size, u64 flags)
8651 struct perf_output_handle handle;
8652 struct perf_sample_data sample;
8653 struct perf_aux_event {
8654 struct perf_event_header header;
8660 .type = PERF_RECORD_AUX,
8662 .size = sizeof(rec),
8670 perf_event_header__init_id(&rec.header, &sample, event);
8671 ret = perf_output_begin(&handle, &sample, event, rec.header.size);
8676 perf_output_put(&handle, rec);
8677 perf_event__output_id_sample(event, &handle, &sample);
8679 perf_output_end(&handle);
8683 * Lost/dropped samples logging
8685 void perf_log_lost_samples(struct perf_event *event, u64 lost)
8687 struct perf_output_handle handle;
8688 struct perf_sample_data sample;
8692 struct perf_event_header header;
8694 } lost_samples_event = {
8696 .type = PERF_RECORD_LOST_SAMPLES,
8698 .size = sizeof(lost_samples_event),
8703 perf_event_header__init_id(&lost_samples_event.header, &sample, event);
8705 ret = perf_output_begin(&handle, &sample, event,
8706 lost_samples_event.header.size);
8710 perf_output_put(&handle, lost_samples_event);
8711 perf_event__output_id_sample(event, &handle, &sample);
8712 perf_output_end(&handle);
8716 * context_switch tracking
8719 struct perf_switch_event {
8720 struct task_struct *task;
8721 struct task_struct *next_prev;
8724 struct perf_event_header header;
8730 static int perf_event_switch_match(struct perf_event *event)
8732 return event->attr.context_switch;
8735 static void perf_event_switch_output(struct perf_event *event, void *data)
8737 struct perf_switch_event *se = data;
8738 struct perf_output_handle handle;
8739 struct perf_sample_data sample;
8742 if (!perf_event_switch_match(event))
8745 /* Only CPU-wide events are allowed to see next/prev pid/tid */
8746 if (event->ctx->task) {
8747 se->event_id.header.type = PERF_RECORD_SWITCH;
8748 se->event_id.header.size = sizeof(se->event_id.header);
8750 se->event_id.header.type = PERF_RECORD_SWITCH_CPU_WIDE;
8751 se->event_id.header.size = sizeof(se->event_id);
8752 se->event_id.next_prev_pid =
8753 perf_event_pid(event, se->next_prev);
8754 se->event_id.next_prev_tid =
8755 perf_event_tid(event, se->next_prev);
8758 perf_event_header__init_id(&se->event_id.header, &sample, event);
8760 ret = perf_output_begin(&handle, &sample, event, se->event_id.header.size);
8764 if (event->ctx->task)
8765 perf_output_put(&handle, se->event_id.header);
8767 perf_output_put(&handle, se->event_id);
8769 perf_event__output_id_sample(event, &handle, &sample);
8771 perf_output_end(&handle);
8774 static void perf_event_switch(struct task_struct *task,
8775 struct task_struct *next_prev, bool sched_in)
8777 struct perf_switch_event switch_event;
8779 /* N.B. caller checks nr_switch_events != 0 */
8781 switch_event = (struct perf_switch_event){
8783 .next_prev = next_prev,
8787 .misc = sched_in ? 0 : PERF_RECORD_MISC_SWITCH_OUT,
8790 /* .next_prev_pid */
8791 /* .next_prev_tid */
8795 if (!sched_in && task->on_rq) {
8796 switch_event.event_id.header.misc |=
8797 PERF_RECORD_MISC_SWITCH_OUT_PREEMPT;
8800 perf_iterate_sb(perf_event_switch_output, &switch_event, NULL);
8804 * IRQ throttle logging
8807 static void perf_log_throttle(struct perf_event *event, int enable)
8809 struct perf_output_handle handle;
8810 struct perf_sample_data sample;
8814 struct perf_event_header header;
8818 } throttle_event = {
8820 .type = PERF_RECORD_THROTTLE,
8822 .size = sizeof(throttle_event),
8824 .time = perf_event_clock(event),
8825 .id = primary_event_id(event),
8826 .stream_id = event->id,
8830 throttle_event.header.type = PERF_RECORD_UNTHROTTLE;
8832 perf_event_header__init_id(&throttle_event.header, &sample, event);
8834 ret = perf_output_begin(&handle, &sample, event,
8835 throttle_event.header.size);
8839 perf_output_put(&handle, throttle_event);
8840 perf_event__output_id_sample(event, &handle, &sample);
8841 perf_output_end(&handle);
8845 * ksymbol register/unregister tracking
8848 struct perf_ksymbol_event {
8852 struct perf_event_header header;
8860 static int perf_event_ksymbol_match(struct perf_event *event)
8862 return event->attr.ksymbol;
8865 static void perf_event_ksymbol_output(struct perf_event *event, void *data)
8867 struct perf_ksymbol_event *ksymbol_event = data;
8868 struct perf_output_handle handle;
8869 struct perf_sample_data sample;
8872 if (!perf_event_ksymbol_match(event))
8875 perf_event_header__init_id(&ksymbol_event->event_id.header,
8877 ret = perf_output_begin(&handle, &sample, event,
8878 ksymbol_event->event_id.header.size);
8882 perf_output_put(&handle, ksymbol_event->event_id);
8883 __output_copy(&handle, ksymbol_event->name, ksymbol_event->name_len);
8884 perf_event__output_id_sample(event, &handle, &sample);
8886 perf_output_end(&handle);
8889 void perf_event_ksymbol(u16 ksym_type, u64 addr, u32 len, bool unregister,
8892 struct perf_ksymbol_event ksymbol_event;
8893 char name[KSYM_NAME_LEN];
8897 if (!atomic_read(&nr_ksymbol_events))
8900 if (ksym_type >= PERF_RECORD_KSYMBOL_TYPE_MAX ||
8901 ksym_type == PERF_RECORD_KSYMBOL_TYPE_UNKNOWN)
8904 strlcpy(name, sym, KSYM_NAME_LEN);
8905 name_len = strlen(name) + 1;
8906 while (!IS_ALIGNED(name_len, sizeof(u64)))
8907 name[name_len++] = '\0';
8908 BUILD_BUG_ON(KSYM_NAME_LEN % sizeof(u64));
8911 flags |= PERF_RECORD_KSYMBOL_FLAGS_UNREGISTER;
8913 ksymbol_event = (struct perf_ksymbol_event){
8915 .name_len = name_len,
8918 .type = PERF_RECORD_KSYMBOL,
8919 .size = sizeof(ksymbol_event.event_id) +
8924 .ksym_type = ksym_type,
8929 perf_iterate_sb(perf_event_ksymbol_output, &ksymbol_event, NULL);
8932 WARN_ONCE(1, "%s: Invalid KSYMBOL type 0x%x\n", __func__, ksym_type);
8936 * bpf program load/unload tracking
8939 struct perf_bpf_event {
8940 struct bpf_prog *prog;
8942 struct perf_event_header header;
8946 u8 tag[BPF_TAG_SIZE];
8950 static int perf_event_bpf_match(struct perf_event *event)
8952 return event->attr.bpf_event;
8955 static void perf_event_bpf_output(struct perf_event *event, void *data)
8957 struct perf_bpf_event *bpf_event = data;
8958 struct perf_output_handle handle;
8959 struct perf_sample_data sample;
8962 if (!perf_event_bpf_match(event))
8965 perf_event_header__init_id(&bpf_event->event_id.header,
8967 ret = perf_output_begin(&handle, data, event,
8968 bpf_event->event_id.header.size);
8972 perf_output_put(&handle, bpf_event->event_id);
8973 perf_event__output_id_sample(event, &handle, &sample);
8975 perf_output_end(&handle);
8978 static void perf_event_bpf_emit_ksymbols(struct bpf_prog *prog,
8979 enum perf_bpf_event_type type)
8981 bool unregister = type == PERF_BPF_EVENT_PROG_UNLOAD;
8984 if (prog->aux->func_cnt == 0) {
8985 perf_event_ksymbol(PERF_RECORD_KSYMBOL_TYPE_BPF,
8986 (u64)(unsigned long)prog->bpf_func,
8987 prog->jited_len, unregister,
8988 prog->aux->ksym.name);
8990 for (i = 0; i < prog->aux->func_cnt; i++) {
8991 struct bpf_prog *subprog = prog->aux->func[i];
8994 PERF_RECORD_KSYMBOL_TYPE_BPF,
8995 (u64)(unsigned long)subprog->bpf_func,
8996 subprog->jited_len, unregister,
8997 prog->aux->ksym.name);
9002 void perf_event_bpf_event(struct bpf_prog *prog,
9003 enum perf_bpf_event_type type,
9006 struct perf_bpf_event bpf_event;
9008 if (type <= PERF_BPF_EVENT_UNKNOWN ||
9009 type >= PERF_BPF_EVENT_MAX)
9013 case PERF_BPF_EVENT_PROG_LOAD:
9014 case PERF_BPF_EVENT_PROG_UNLOAD:
9015 if (atomic_read(&nr_ksymbol_events))
9016 perf_event_bpf_emit_ksymbols(prog, type);
9022 if (!atomic_read(&nr_bpf_events))
9025 bpf_event = (struct perf_bpf_event){
9029 .type = PERF_RECORD_BPF_EVENT,
9030 .size = sizeof(bpf_event.event_id),
9034 .id = prog->aux->id,
9038 BUILD_BUG_ON(BPF_TAG_SIZE % sizeof(u64));
9040 memcpy(bpf_event.event_id.tag, prog->tag, BPF_TAG_SIZE);
9041 perf_iterate_sb(perf_event_bpf_output, &bpf_event, NULL);
9044 struct perf_text_poke_event {
9045 const void *old_bytes;
9046 const void *new_bytes;
9052 struct perf_event_header header;
9058 static int perf_event_text_poke_match(struct perf_event *event)
9060 return event->attr.text_poke;
9063 static void perf_event_text_poke_output(struct perf_event *event, void *data)
9065 struct perf_text_poke_event *text_poke_event = data;
9066 struct perf_output_handle handle;
9067 struct perf_sample_data sample;
9071 if (!perf_event_text_poke_match(event))
9074 perf_event_header__init_id(&text_poke_event->event_id.header, &sample, event);
9076 ret = perf_output_begin(&handle, &sample, event,
9077 text_poke_event->event_id.header.size);
9081 perf_output_put(&handle, text_poke_event->event_id);
9082 perf_output_put(&handle, text_poke_event->old_len);
9083 perf_output_put(&handle, text_poke_event->new_len);
9085 __output_copy(&handle, text_poke_event->old_bytes, text_poke_event->old_len);
9086 __output_copy(&handle, text_poke_event->new_bytes, text_poke_event->new_len);
9088 if (text_poke_event->pad)
9089 __output_copy(&handle, &padding, text_poke_event->pad);
9091 perf_event__output_id_sample(event, &handle, &sample);
9093 perf_output_end(&handle);
9096 void perf_event_text_poke(const void *addr, const void *old_bytes,
9097 size_t old_len, const void *new_bytes, size_t new_len)
9099 struct perf_text_poke_event text_poke_event;
9102 if (!atomic_read(&nr_text_poke_events))
9105 tot = sizeof(text_poke_event.old_len) + old_len;
9106 tot += sizeof(text_poke_event.new_len) + new_len;
9107 pad = ALIGN(tot, sizeof(u64)) - tot;
9109 text_poke_event = (struct perf_text_poke_event){
9110 .old_bytes = old_bytes,
9111 .new_bytes = new_bytes,
9117 .type = PERF_RECORD_TEXT_POKE,
9118 .misc = PERF_RECORD_MISC_KERNEL,
9119 .size = sizeof(text_poke_event.event_id) + tot + pad,
9121 .addr = (unsigned long)addr,
9125 perf_iterate_sb(perf_event_text_poke_output, &text_poke_event, NULL);
9128 void perf_event_itrace_started(struct perf_event *event)
9130 event->attach_state |= PERF_ATTACH_ITRACE;
9133 static void perf_log_itrace_start(struct perf_event *event)
9135 struct perf_output_handle handle;
9136 struct perf_sample_data sample;
9137 struct perf_aux_event {
9138 struct perf_event_header header;
9145 event = event->parent;
9147 if (!(event->pmu->capabilities & PERF_PMU_CAP_ITRACE) ||
9148 event->attach_state & PERF_ATTACH_ITRACE)
9151 rec.header.type = PERF_RECORD_ITRACE_START;
9152 rec.header.misc = 0;
9153 rec.header.size = sizeof(rec);
9154 rec.pid = perf_event_pid(event, current);
9155 rec.tid = perf_event_tid(event, current);
9157 perf_event_header__init_id(&rec.header, &sample, event);
9158 ret = perf_output_begin(&handle, &sample, event, rec.header.size);
9163 perf_output_put(&handle, rec);
9164 perf_event__output_id_sample(event, &handle, &sample);
9166 perf_output_end(&handle);
9169 void perf_report_aux_output_id(struct perf_event *event, u64 hw_id)
9171 struct perf_output_handle handle;
9172 struct perf_sample_data sample;
9173 struct perf_aux_event {
9174 struct perf_event_header header;
9180 event = event->parent;
9182 rec.header.type = PERF_RECORD_AUX_OUTPUT_HW_ID;
9183 rec.header.misc = 0;
9184 rec.header.size = sizeof(rec);
9187 perf_event_header__init_id(&rec.header, &sample, event);
9188 ret = perf_output_begin(&handle, &sample, event, rec.header.size);
9193 perf_output_put(&handle, rec);
9194 perf_event__output_id_sample(event, &handle, &sample);
9196 perf_output_end(&handle);
9200 __perf_event_account_interrupt(struct perf_event *event, int throttle)
9202 struct hw_perf_event *hwc = &event->hw;
9206 seq = __this_cpu_read(perf_throttled_seq);
9207 if (seq != hwc->interrupts_seq) {
9208 hwc->interrupts_seq = seq;
9209 hwc->interrupts = 1;
9212 if (unlikely(throttle
9213 && hwc->interrupts >= max_samples_per_tick)) {
9214 __this_cpu_inc(perf_throttled_count);
9215 tick_dep_set_cpu(smp_processor_id(), TICK_DEP_BIT_PERF_EVENTS);
9216 hwc->interrupts = MAX_INTERRUPTS;
9217 perf_log_throttle(event, 0);
9222 if (event->attr.freq) {
9223 u64 now = perf_clock();
9224 s64 delta = now - hwc->freq_time_stamp;
9226 hwc->freq_time_stamp = now;
9228 if (delta > 0 && delta < 2*TICK_NSEC)
9229 perf_adjust_period(event, delta, hwc->last_period, true);
9235 int perf_event_account_interrupt(struct perf_event *event)
9237 return __perf_event_account_interrupt(event, 1);
9241 * Generic event overflow handling, sampling.
9244 static int __perf_event_overflow(struct perf_event *event,
9245 int throttle, struct perf_sample_data *data,
9246 struct pt_regs *regs)
9248 int events = atomic_read(&event->event_limit);
9252 * Non-sampling counters might still use the PMI to fold short
9253 * hardware counters, ignore those.
9255 if (unlikely(!is_sampling_event(event)))
9258 ret = __perf_event_account_interrupt(event, throttle);
9261 * XXX event_limit might not quite work as expected on inherited
9265 event->pending_kill = POLL_IN;
9266 if (events && atomic_dec_and_test(&event->event_limit)) {
9268 event->pending_kill = POLL_HUP;
9269 event->pending_addr = data->addr;
9271 perf_event_disable_inatomic(event);
9274 READ_ONCE(event->overflow_handler)(event, data, regs);
9276 if (*perf_event_fasync(event) && event->pending_kill) {
9277 event->pending_wakeup = 1;
9278 irq_work_queue(&event->pending);
9284 int perf_event_overflow(struct perf_event *event,
9285 struct perf_sample_data *data,
9286 struct pt_regs *regs)
9288 return __perf_event_overflow(event, 1, data, regs);
9292 * Generic software event infrastructure
9295 struct swevent_htable {
9296 struct swevent_hlist *swevent_hlist;
9297 struct mutex hlist_mutex;
9300 /* Recursion avoidance in each contexts */
9301 int recursion[PERF_NR_CONTEXTS];
9304 static DEFINE_PER_CPU(struct swevent_htable, swevent_htable);
9307 * We directly increment event->count and keep a second value in
9308 * event->hw.period_left to count intervals. This period event
9309 * is kept in the range [-sample_period, 0] so that we can use the
9313 u64 perf_swevent_set_period(struct perf_event *event)
9315 struct hw_perf_event *hwc = &event->hw;
9316 u64 period = hwc->last_period;
9320 hwc->last_period = hwc->sample_period;
9323 old = val = local64_read(&hwc->period_left);
9327 nr = div64_u64(period + val, period);
9328 offset = nr * period;
9330 if (local64_cmpxchg(&hwc->period_left, old, val) != old)
9336 static void perf_swevent_overflow(struct perf_event *event, u64 overflow,
9337 struct perf_sample_data *data,
9338 struct pt_regs *regs)
9340 struct hw_perf_event *hwc = &event->hw;
9344 overflow = perf_swevent_set_period(event);
9346 if (hwc->interrupts == MAX_INTERRUPTS)
9349 for (; overflow; overflow--) {
9350 if (__perf_event_overflow(event, throttle,
9353 * We inhibit the overflow from happening when
9354 * hwc->interrupts == MAX_INTERRUPTS.
9362 static void perf_swevent_event(struct perf_event *event, u64 nr,
9363 struct perf_sample_data *data,
9364 struct pt_regs *regs)
9366 struct hw_perf_event *hwc = &event->hw;
9368 local64_add(nr, &event->count);
9373 if (!is_sampling_event(event))
9376 if ((event->attr.sample_type & PERF_SAMPLE_PERIOD) && !event->attr.freq) {
9378 return perf_swevent_overflow(event, 1, data, regs);
9380 data->period = event->hw.last_period;
9382 if (nr == 1 && hwc->sample_period == 1 && !event->attr.freq)
9383 return perf_swevent_overflow(event, 1, data, regs);
9385 if (local64_add_negative(nr, &hwc->period_left))
9388 perf_swevent_overflow(event, 0, data, regs);
9391 static int perf_exclude_event(struct perf_event *event,
9392 struct pt_regs *regs)
9394 if (event->hw.state & PERF_HES_STOPPED)
9398 if (event->attr.exclude_user && user_mode(regs))
9401 if (event->attr.exclude_kernel && !user_mode(regs))
9408 static int perf_swevent_match(struct perf_event *event,
9409 enum perf_type_id type,
9411 struct perf_sample_data *data,
9412 struct pt_regs *regs)
9414 if (event->attr.type != type)
9417 if (event->attr.config != event_id)
9420 if (perf_exclude_event(event, regs))
9426 static inline u64 swevent_hash(u64 type, u32 event_id)
9428 u64 val = event_id | (type << 32);
9430 return hash_64(val, SWEVENT_HLIST_BITS);
9433 static inline struct hlist_head *
9434 __find_swevent_head(struct swevent_hlist *hlist, u64 type, u32 event_id)
9436 u64 hash = swevent_hash(type, event_id);
9438 return &hlist->heads[hash];
9441 /* For the read side: events when they trigger */
9442 static inline struct hlist_head *
9443 find_swevent_head_rcu(struct swevent_htable *swhash, u64 type, u32 event_id)
9445 struct swevent_hlist *hlist;
9447 hlist = rcu_dereference(swhash->swevent_hlist);
9451 return __find_swevent_head(hlist, type, event_id);
9454 /* For the event head insertion and removal in the hlist */
9455 static inline struct hlist_head *
9456 find_swevent_head(struct swevent_htable *swhash, struct perf_event *event)
9458 struct swevent_hlist *hlist;
9459 u32 event_id = event->attr.config;
9460 u64 type = event->attr.type;
9463 * Event scheduling is always serialized against hlist allocation
9464 * and release. Which makes the protected version suitable here.
9465 * The context lock guarantees that.
9467 hlist = rcu_dereference_protected(swhash->swevent_hlist,
9468 lockdep_is_held(&event->ctx->lock));
9472 return __find_swevent_head(hlist, type, event_id);
9475 static void do_perf_sw_event(enum perf_type_id type, u32 event_id,
9477 struct perf_sample_data *data,
9478 struct pt_regs *regs)
9480 struct swevent_htable *swhash = this_cpu_ptr(&swevent_htable);
9481 struct perf_event *event;
9482 struct hlist_head *head;
9485 head = find_swevent_head_rcu(swhash, type, event_id);
9489 hlist_for_each_entry_rcu(event, head, hlist_entry) {
9490 if (perf_swevent_match(event, type, event_id, data, regs))
9491 perf_swevent_event(event, nr, data, regs);
9497 DEFINE_PER_CPU(struct pt_regs, __perf_regs[4]);
9499 int perf_swevent_get_recursion_context(void)
9501 struct swevent_htable *swhash = this_cpu_ptr(&swevent_htable);
9503 return get_recursion_context(swhash->recursion);
9505 EXPORT_SYMBOL_GPL(perf_swevent_get_recursion_context);
9507 void perf_swevent_put_recursion_context(int rctx)
9509 struct swevent_htable *swhash = this_cpu_ptr(&swevent_htable);
9511 put_recursion_context(swhash->recursion, rctx);
9514 void ___perf_sw_event(u32 event_id, u64 nr, struct pt_regs *regs, u64 addr)
9516 struct perf_sample_data data;
9518 if (WARN_ON_ONCE(!regs))
9521 perf_sample_data_init(&data, addr, 0);
9522 do_perf_sw_event(PERF_TYPE_SOFTWARE, event_id, nr, &data, regs);
9525 void __perf_sw_event(u32 event_id, u64 nr, struct pt_regs *regs, u64 addr)
9529 preempt_disable_notrace();
9530 rctx = perf_swevent_get_recursion_context();
9531 if (unlikely(rctx < 0))
9534 ___perf_sw_event(event_id, nr, regs, addr);
9536 perf_swevent_put_recursion_context(rctx);
9538 preempt_enable_notrace();
9541 static void perf_swevent_read(struct perf_event *event)
9545 static int perf_swevent_add(struct perf_event *event, int flags)
9547 struct swevent_htable *swhash = this_cpu_ptr(&swevent_htable);
9548 struct hw_perf_event *hwc = &event->hw;
9549 struct hlist_head *head;
9551 if (is_sampling_event(event)) {
9552 hwc->last_period = hwc->sample_period;
9553 perf_swevent_set_period(event);
9556 hwc->state = !(flags & PERF_EF_START);
9558 head = find_swevent_head(swhash, event);
9559 if (WARN_ON_ONCE(!head))
9562 hlist_add_head_rcu(&event->hlist_entry, head);
9563 perf_event_update_userpage(event);
9568 static void perf_swevent_del(struct perf_event *event, int flags)
9570 hlist_del_rcu(&event->hlist_entry);
9573 static void perf_swevent_start(struct perf_event *event, int flags)
9575 event->hw.state = 0;
9578 static void perf_swevent_stop(struct perf_event *event, int flags)
9580 event->hw.state = PERF_HES_STOPPED;
9583 /* Deref the hlist from the update side */
9584 static inline struct swevent_hlist *
9585 swevent_hlist_deref(struct swevent_htable *swhash)
9587 return rcu_dereference_protected(swhash->swevent_hlist,
9588 lockdep_is_held(&swhash->hlist_mutex));
9591 static void swevent_hlist_release(struct swevent_htable *swhash)
9593 struct swevent_hlist *hlist = swevent_hlist_deref(swhash);
9598 RCU_INIT_POINTER(swhash->swevent_hlist, NULL);
9599 kfree_rcu(hlist, rcu_head);
9602 static void swevent_hlist_put_cpu(int cpu)
9604 struct swevent_htable *swhash = &per_cpu(swevent_htable, cpu);
9606 mutex_lock(&swhash->hlist_mutex);
9608 if (!--swhash->hlist_refcount)
9609 swevent_hlist_release(swhash);
9611 mutex_unlock(&swhash->hlist_mutex);
9614 static void swevent_hlist_put(void)
9618 for_each_possible_cpu(cpu)
9619 swevent_hlist_put_cpu(cpu);
9622 static int swevent_hlist_get_cpu(int cpu)
9624 struct swevent_htable *swhash = &per_cpu(swevent_htable, cpu);
9627 mutex_lock(&swhash->hlist_mutex);
9628 if (!swevent_hlist_deref(swhash) &&
9629 cpumask_test_cpu(cpu, perf_online_mask)) {
9630 struct swevent_hlist *hlist;
9632 hlist = kzalloc(sizeof(*hlist), GFP_KERNEL);
9637 rcu_assign_pointer(swhash->swevent_hlist, hlist);
9639 swhash->hlist_refcount++;
9641 mutex_unlock(&swhash->hlist_mutex);
9646 static int swevent_hlist_get(void)
9648 int err, cpu, failed_cpu;
9650 mutex_lock(&pmus_lock);
9651 for_each_possible_cpu(cpu) {
9652 err = swevent_hlist_get_cpu(cpu);
9658 mutex_unlock(&pmus_lock);
9661 for_each_possible_cpu(cpu) {
9662 if (cpu == failed_cpu)
9664 swevent_hlist_put_cpu(cpu);
9666 mutex_unlock(&pmus_lock);
9670 struct static_key perf_swevent_enabled[PERF_COUNT_SW_MAX];
9672 static void sw_perf_event_destroy(struct perf_event *event)
9674 u64 event_id = event->attr.config;
9676 WARN_ON(event->parent);
9678 static_key_slow_dec(&perf_swevent_enabled[event_id]);
9679 swevent_hlist_put();
9682 static int perf_swevent_init(struct perf_event *event)
9684 u64 event_id = event->attr.config;
9686 if (event->attr.type != PERF_TYPE_SOFTWARE)
9690 * no branch sampling for software events
9692 if (has_branch_stack(event))
9696 case PERF_COUNT_SW_CPU_CLOCK:
9697 case PERF_COUNT_SW_TASK_CLOCK:
9704 if (event_id >= PERF_COUNT_SW_MAX)
9707 if (!event->parent) {
9710 err = swevent_hlist_get();
9714 static_key_slow_inc(&perf_swevent_enabled[event_id]);
9715 event->destroy = sw_perf_event_destroy;
9721 static struct pmu perf_swevent = {
9722 .task_ctx_nr = perf_sw_context,
9724 .capabilities = PERF_PMU_CAP_NO_NMI,
9726 .event_init = perf_swevent_init,
9727 .add = perf_swevent_add,
9728 .del = perf_swevent_del,
9729 .start = perf_swevent_start,
9730 .stop = perf_swevent_stop,
9731 .read = perf_swevent_read,
9734 #ifdef CONFIG_EVENT_TRACING
9736 static int perf_tp_filter_match(struct perf_event *event,
9737 struct perf_sample_data *data)
9739 void *record = data->raw->frag.data;
9741 /* only top level events have filters set */
9743 event = event->parent;
9745 if (likely(!event->filter) || filter_match_preds(event->filter, record))
9750 static int perf_tp_event_match(struct perf_event *event,
9751 struct perf_sample_data *data,
9752 struct pt_regs *regs)
9754 if (event->hw.state & PERF_HES_STOPPED)
9757 * If exclude_kernel, only trace user-space tracepoints (uprobes)
9759 if (event->attr.exclude_kernel && !user_mode(regs))
9762 if (!perf_tp_filter_match(event, data))
9768 void perf_trace_run_bpf_submit(void *raw_data, int size, int rctx,
9769 struct trace_event_call *call, u64 count,
9770 struct pt_regs *regs, struct hlist_head *head,
9771 struct task_struct *task)
9773 if (bpf_prog_array_valid(call)) {
9774 *(struct pt_regs **)raw_data = regs;
9775 if (!trace_call_bpf(call, raw_data) || hlist_empty(head)) {
9776 perf_swevent_put_recursion_context(rctx);
9780 perf_tp_event(call->event.type, count, raw_data, size, regs, head,
9783 EXPORT_SYMBOL_GPL(perf_trace_run_bpf_submit);
9785 void perf_tp_event(u16 event_type, u64 count, void *record, int entry_size,
9786 struct pt_regs *regs, struct hlist_head *head, int rctx,
9787 struct task_struct *task)
9789 struct perf_sample_data data;
9790 struct perf_event *event;
9792 struct perf_raw_record raw = {
9799 perf_sample_data_init(&data, 0, 0);
9802 perf_trace_buf_update(record, event_type);
9804 hlist_for_each_entry_rcu(event, head, hlist_entry) {
9805 if (perf_tp_event_match(event, &data, regs))
9806 perf_swevent_event(event, count, &data, regs);
9810 * If we got specified a target task, also iterate its context and
9811 * deliver this event there too.
9813 if (task && task != current) {
9814 struct perf_event_context *ctx;
9815 struct trace_entry *entry = record;
9818 ctx = rcu_dereference(task->perf_event_ctxp[perf_sw_context]);
9822 list_for_each_entry_rcu(event, &ctx->event_list, event_entry) {
9823 if (event->cpu != smp_processor_id())
9825 if (event->attr.type != PERF_TYPE_TRACEPOINT)
9827 if (event->attr.config != entry->type)
9829 /* Cannot deliver synchronous signal to other task. */
9830 if (event->attr.sigtrap)
9832 if (perf_tp_event_match(event, &data, regs))
9833 perf_swevent_event(event, count, &data, regs);
9839 perf_swevent_put_recursion_context(rctx);
9841 EXPORT_SYMBOL_GPL(perf_tp_event);
9843 static void tp_perf_event_destroy(struct perf_event *event)
9845 perf_trace_destroy(event);
9848 static int perf_tp_event_init(struct perf_event *event)
9852 if (event->attr.type != PERF_TYPE_TRACEPOINT)
9856 * no branch sampling for tracepoint events
9858 if (has_branch_stack(event))
9861 err = perf_trace_init(event);
9865 event->destroy = tp_perf_event_destroy;
9870 static struct pmu perf_tracepoint = {
9871 .task_ctx_nr = perf_sw_context,
9873 .event_init = perf_tp_event_init,
9874 .add = perf_trace_add,
9875 .del = perf_trace_del,
9876 .start = perf_swevent_start,
9877 .stop = perf_swevent_stop,
9878 .read = perf_swevent_read,
9881 #if defined(CONFIG_KPROBE_EVENTS) || defined(CONFIG_UPROBE_EVENTS)
9883 * Flags in config, used by dynamic PMU kprobe and uprobe
9884 * The flags should match following PMU_FORMAT_ATTR().
9886 * PERF_PROBE_CONFIG_IS_RETPROBE if set, create kretprobe/uretprobe
9887 * if not set, create kprobe/uprobe
9889 * The following values specify a reference counter (or semaphore in the
9890 * terminology of tools like dtrace, systemtap, etc.) Userspace Statically
9891 * Defined Tracepoints (USDT). Currently, we use 40 bit for the offset.
9893 * PERF_UPROBE_REF_CTR_OFFSET_BITS # of bits in config as th offset
9894 * PERF_UPROBE_REF_CTR_OFFSET_SHIFT # of bits to shift left
9896 enum perf_probe_config {
9897 PERF_PROBE_CONFIG_IS_RETPROBE = 1U << 0, /* [k,u]retprobe */
9898 PERF_UPROBE_REF_CTR_OFFSET_BITS = 32,
9899 PERF_UPROBE_REF_CTR_OFFSET_SHIFT = 64 - PERF_UPROBE_REF_CTR_OFFSET_BITS,
9902 PMU_FORMAT_ATTR(retprobe, "config:0");
9905 #ifdef CONFIG_KPROBE_EVENTS
9906 static struct attribute *kprobe_attrs[] = {
9907 &format_attr_retprobe.attr,
9911 static struct attribute_group kprobe_format_group = {
9913 .attrs = kprobe_attrs,
9916 static const struct attribute_group *kprobe_attr_groups[] = {
9917 &kprobe_format_group,
9921 static int perf_kprobe_event_init(struct perf_event *event);
9922 static struct pmu perf_kprobe = {
9923 .task_ctx_nr = perf_sw_context,
9924 .event_init = perf_kprobe_event_init,
9925 .add = perf_trace_add,
9926 .del = perf_trace_del,
9927 .start = perf_swevent_start,
9928 .stop = perf_swevent_stop,
9929 .read = perf_swevent_read,
9930 .attr_groups = kprobe_attr_groups,
9933 static int perf_kprobe_event_init(struct perf_event *event)
9938 if (event->attr.type != perf_kprobe.type)
9941 if (!perfmon_capable())
9945 * no branch sampling for probe events
9947 if (has_branch_stack(event))
9950 is_retprobe = event->attr.config & PERF_PROBE_CONFIG_IS_RETPROBE;
9951 err = perf_kprobe_init(event, is_retprobe);
9955 event->destroy = perf_kprobe_destroy;
9959 #endif /* CONFIG_KPROBE_EVENTS */
9961 #ifdef CONFIG_UPROBE_EVENTS
9962 PMU_FORMAT_ATTR(ref_ctr_offset, "config:32-63");
9964 static struct attribute *uprobe_attrs[] = {
9965 &format_attr_retprobe.attr,
9966 &format_attr_ref_ctr_offset.attr,
9970 static struct attribute_group uprobe_format_group = {
9972 .attrs = uprobe_attrs,
9975 static const struct attribute_group *uprobe_attr_groups[] = {
9976 &uprobe_format_group,
9980 static int perf_uprobe_event_init(struct perf_event *event);
9981 static struct pmu perf_uprobe = {
9982 .task_ctx_nr = perf_sw_context,
9983 .event_init = perf_uprobe_event_init,
9984 .add = perf_trace_add,
9985 .del = perf_trace_del,
9986 .start = perf_swevent_start,
9987 .stop = perf_swevent_stop,
9988 .read = perf_swevent_read,
9989 .attr_groups = uprobe_attr_groups,
9992 static int perf_uprobe_event_init(struct perf_event *event)
9995 unsigned long ref_ctr_offset;
9998 if (event->attr.type != perf_uprobe.type)
10001 if (!perfmon_capable())
10005 * no branch sampling for probe events
10007 if (has_branch_stack(event))
10008 return -EOPNOTSUPP;
10010 is_retprobe = event->attr.config & PERF_PROBE_CONFIG_IS_RETPROBE;
10011 ref_ctr_offset = event->attr.config >> PERF_UPROBE_REF_CTR_OFFSET_SHIFT;
10012 err = perf_uprobe_init(event, ref_ctr_offset, is_retprobe);
10016 event->destroy = perf_uprobe_destroy;
10020 #endif /* CONFIG_UPROBE_EVENTS */
10022 static inline void perf_tp_register(void)
10024 perf_pmu_register(&perf_tracepoint, "tracepoint", PERF_TYPE_TRACEPOINT);
10025 #ifdef CONFIG_KPROBE_EVENTS
10026 perf_pmu_register(&perf_kprobe, "kprobe", -1);
10028 #ifdef CONFIG_UPROBE_EVENTS
10029 perf_pmu_register(&perf_uprobe, "uprobe", -1);
10033 static void perf_event_free_filter(struct perf_event *event)
10035 ftrace_profile_free_filter(event);
10038 #ifdef CONFIG_BPF_SYSCALL
10039 static void bpf_overflow_handler(struct perf_event *event,
10040 struct perf_sample_data *data,
10041 struct pt_regs *regs)
10043 struct bpf_perf_event_data_kern ctx = {
10047 struct bpf_prog *prog;
10050 ctx.regs = perf_arch_bpf_user_pt_regs(regs);
10051 if (unlikely(__this_cpu_inc_return(bpf_prog_active) != 1))
10054 prog = READ_ONCE(event->prog);
10056 ret = bpf_prog_run(prog, &ctx);
10059 __this_cpu_dec(bpf_prog_active);
10063 event->orig_overflow_handler(event, data, regs);
10066 static int perf_event_set_bpf_handler(struct perf_event *event,
10067 struct bpf_prog *prog,
10070 if (event->overflow_handler_context)
10071 /* hw breakpoint or kernel counter */
10077 if (prog->type != BPF_PROG_TYPE_PERF_EVENT)
10080 if (event->attr.precise_ip &&
10081 prog->call_get_stack &&
10082 (!(event->attr.sample_type & __PERF_SAMPLE_CALLCHAIN_EARLY) ||
10083 event->attr.exclude_callchain_kernel ||
10084 event->attr.exclude_callchain_user)) {
10086 * On perf_event with precise_ip, calling bpf_get_stack()
10087 * may trigger unwinder warnings and occasional crashes.
10088 * bpf_get_[stack|stackid] works around this issue by using
10089 * callchain attached to perf_sample_data. If the
10090 * perf_event does not full (kernel and user) callchain
10091 * attached to perf_sample_data, do not allow attaching BPF
10092 * program that calls bpf_get_[stack|stackid].
10097 event->prog = prog;
10098 event->bpf_cookie = bpf_cookie;
10099 event->orig_overflow_handler = READ_ONCE(event->overflow_handler);
10100 WRITE_ONCE(event->overflow_handler, bpf_overflow_handler);
10104 static void perf_event_free_bpf_handler(struct perf_event *event)
10106 struct bpf_prog *prog = event->prog;
10111 WRITE_ONCE(event->overflow_handler, event->orig_overflow_handler);
10112 event->prog = NULL;
10113 bpf_prog_put(prog);
10116 static int perf_event_set_bpf_handler(struct perf_event *event,
10117 struct bpf_prog *prog,
10120 return -EOPNOTSUPP;
10122 static void perf_event_free_bpf_handler(struct perf_event *event)
10128 * returns true if the event is a tracepoint, or a kprobe/upprobe created
10129 * with perf_event_open()
10131 static inline bool perf_event_is_tracing(struct perf_event *event)
10133 if (event->pmu == &perf_tracepoint)
10135 #ifdef CONFIG_KPROBE_EVENTS
10136 if (event->pmu == &perf_kprobe)
10139 #ifdef CONFIG_UPROBE_EVENTS
10140 if (event->pmu == &perf_uprobe)
10146 int perf_event_set_bpf_prog(struct perf_event *event, struct bpf_prog *prog,
10149 bool is_kprobe, is_tracepoint, is_syscall_tp;
10151 if (!perf_event_is_tracing(event))
10152 return perf_event_set_bpf_handler(event, prog, bpf_cookie);
10154 is_kprobe = event->tp_event->flags & TRACE_EVENT_FL_UKPROBE;
10155 is_tracepoint = event->tp_event->flags & TRACE_EVENT_FL_TRACEPOINT;
10156 is_syscall_tp = is_syscall_trace_event(event->tp_event);
10157 if (!is_kprobe && !is_tracepoint && !is_syscall_tp)
10158 /* bpf programs can only be attached to u/kprobe or tracepoint */
10161 if ((is_kprobe && prog->type != BPF_PROG_TYPE_KPROBE) ||
10162 (is_tracepoint && prog->type != BPF_PROG_TYPE_TRACEPOINT) ||
10163 (is_syscall_tp && prog->type != BPF_PROG_TYPE_TRACEPOINT))
10166 /* Kprobe override only works for kprobes, not uprobes. */
10167 if (prog->kprobe_override &&
10168 !(event->tp_event->flags & TRACE_EVENT_FL_KPROBE))
10171 if (is_tracepoint || is_syscall_tp) {
10172 int off = trace_event_get_offsets(event->tp_event);
10174 if (prog->aux->max_ctx_offset > off)
10178 return perf_event_attach_bpf_prog(event, prog, bpf_cookie);
10181 void perf_event_free_bpf_prog(struct perf_event *event)
10183 if (!perf_event_is_tracing(event)) {
10184 perf_event_free_bpf_handler(event);
10187 perf_event_detach_bpf_prog(event);
10192 static inline void perf_tp_register(void)
10196 static void perf_event_free_filter(struct perf_event *event)
10200 int perf_event_set_bpf_prog(struct perf_event *event, struct bpf_prog *prog,
10206 void perf_event_free_bpf_prog(struct perf_event *event)
10209 #endif /* CONFIG_EVENT_TRACING */
10211 #ifdef CONFIG_HAVE_HW_BREAKPOINT
10212 void perf_bp_event(struct perf_event *bp, void *data)
10214 struct perf_sample_data sample;
10215 struct pt_regs *regs = data;
10217 perf_sample_data_init(&sample, bp->attr.bp_addr, 0);
10219 if (!bp->hw.state && !perf_exclude_event(bp, regs))
10220 perf_swevent_event(bp, 1, &sample, regs);
10225 * Allocate a new address filter
10227 static struct perf_addr_filter *
10228 perf_addr_filter_new(struct perf_event *event, struct list_head *filters)
10230 int node = cpu_to_node(event->cpu == -1 ? 0 : event->cpu);
10231 struct perf_addr_filter *filter;
10233 filter = kzalloc_node(sizeof(*filter), GFP_KERNEL, node);
10237 INIT_LIST_HEAD(&filter->entry);
10238 list_add_tail(&filter->entry, filters);
10243 static void free_filters_list(struct list_head *filters)
10245 struct perf_addr_filter *filter, *iter;
10247 list_for_each_entry_safe(filter, iter, filters, entry) {
10248 path_put(&filter->path);
10249 list_del(&filter->entry);
10255 * Free existing address filters and optionally install new ones
10257 static void perf_addr_filters_splice(struct perf_event *event,
10258 struct list_head *head)
10260 unsigned long flags;
10263 if (!has_addr_filter(event))
10266 /* don't bother with children, they don't have their own filters */
10270 raw_spin_lock_irqsave(&event->addr_filters.lock, flags);
10272 list_splice_init(&event->addr_filters.list, &list);
10274 list_splice(head, &event->addr_filters.list);
10276 raw_spin_unlock_irqrestore(&event->addr_filters.lock, flags);
10278 free_filters_list(&list);
10282 * Scan through mm's vmas and see if one of them matches the
10283 * @filter; if so, adjust filter's address range.
10284 * Called with mm::mmap_lock down for reading.
10286 static void perf_addr_filter_apply(struct perf_addr_filter *filter,
10287 struct mm_struct *mm,
10288 struct perf_addr_filter_range *fr)
10290 struct vm_area_struct *vma;
10292 for (vma = mm->mmap; vma; vma = vma->vm_next) {
10296 if (perf_addr_filter_vma_adjust(filter, vma, fr))
10302 * Update event's address range filters based on the
10303 * task's existing mappings, if any.
10305 static void perf_event_addr_filters_apply(struct perf_event *event)
10307 struct perf_addr_filters_head *ifh = perf_event_addr_filters(event);
10308 struct task_struct *task = READ_ONCE(event->ctx->task);
10309 struct perf_addr_filter *filter;
10310 struct mm_struct *mm = NULL;
10311 unsigned int count = 0;
10312 unsigned long flags;
10315 * We may observe TASK_TOMBSTONE, which means that the event tear-down
10316 * will stop on the parent's child_mutex that our caller is also holding
10318 if (task == TASK_TOMBSTONE)
10321 if (ifh->nr_file_filters) {
10322 mm = get_task_mm(task);
10326 mmap_read_lock(mm);
10329 raw_spin_lock_irqsave(&ifh->lock, flags);
10330 list_for_each_entry(filter, &ifh->list, entry) {
10331 if (filter->path.dentry) {
10333 * Adjust base offset if the filter is associated to a
10334 * binary that needs to be mapped:
10336 event->addr_filter_ranges[count].start = 0;
10337 event->addr_filter_ranges[count].size = 0;
10339 perf_addr_filter_apply(filter, mm, &event->addr_filter_ranges[count]);
10341 event->addr_filter_ranges[count].start = filter->offset;
10342 event->addr_filter_ranges[count].size = filter->size;
10348 event->addr_filters_gen++;
10349 raw_spin_unlock_irqrestore(&ifh->lock, flags);
10351 if (ifh->nr_file_filters) {
10352 mmap_read_unlock(mm);
10358 perf_event_stop(event, 1);
10362 * Address range filtering: limiting the data to certain
10363 * instruction address ranges. Filters are ioctl()ed to us from
10364 * userspace as ascii strings.
10366 * Filter string format:
10368 * ACTION RANGE_SPEC
10369 * where ACTION is one of the
10370 * * "filter": limit the trace to this region
10371 * * "start": start tracing from this address
10372 * * "stop": stop tracing at this address/region;
10374 * * for kernel addresses: <start address>[/<size>]
10375 * * for object files: <start address>[/<size>]@</path/to/object/file>
10377 * if <size> is not specified or is zero, the range is treated as a single
10378 * address; not valid for ACTION=="filter".
10392 IF_STATE_ACTION = 0,
10397 static const match_table_t if_tokens = {
10398 { IF_ACT_FILTER, "filter" },
10399 { IF_ACT_START, "start" },
10400 { IF_ACT_STOP, "stop" },
10401 { IF_SRC_FILE, "%u/%u@%s" },
10402 { IF_SRC_KERNEL, "%u/%u" },
10403 { IF_SRC_FILEADDR, "%u@%s" },
10404 { IF_SRC_KERNELADDR, "%u" },
10405 { IF_ACT_NONE, NULL },
10409 * Address filter string parser
10412 perf_event_parse_addr_filter(struct perf_event *event, char *fstr,
10413 struct list_head *filters)
10415 struct perf_addr_filter *filter = NULL;
10416 char *start, *orig, *filename = NULL;
10417 substring_t args[MAX_OPT_ARGS];
10418 int state = IF_STATE_ACTION, token;
10419 unsigned int kernel = 0;
10422 orig = fstr = kstrdup(fstr, GFP_KERNEL);
10426 while ((start = strsep(&fstr, " ,\n")) != NULL) {
10427 static const enum perf_addr_filter_action_t actions[] = {
10428 [IF_ACT_FILTER] = PERF_ADDR_FILTER_ACTION_FILTER,
10429 [IF_ACT_START] = PERF_ADDR_FILTER_ACTION_START,
10430 [IF_ACT_STOP] = PERF_ADDR_FILTER_ACTION_STOP,
10437 /* filter definition begins */
10438 if (state == IF_STATE_ACTION) {
10439 filter = perf_addr_filter_new(event, filters);
10444 token = match_token(start, if_tokens, args);
10446 case IF_ACT_FILTER:
10449 if (state != IF_STATE_ACTION)
10452 filter->action = actions[token];
10453 state = IF_STATE_SOURCE;
10456 case IF_SRC_KERNELADDR:
10457 case IF_SRC_KERNEL:
10461 case IF_SRC_FILEADDR:
10463 if (state != IF_STATE_SOURCE)
10467 ret = kstrtoul(args[0].from, 0, &filter->offset);
10471 if (token == IF_SRC_KERNEL || token == IF_SRC_FILE) {
10473 ret = kstrtoul(args[1].from, 0, &filter->size);
10478 if (token == IF_SRC_FILE || token == IF_SRC_FILEADDR) {
10479 int fpos = token == IF_SRC_FILE ? 2 : 1;
10482 filename = match_strdup(&args[fpos]);
10489 state = IF_STATE_END;
10497 * Filter definition is fully parsed, validate and install it.
10498 * Make sure that it doesn't contradict itself or the event's
10501 if (state == IF_STATE_END) {
10503 if (kernel && event->attr.exclude_kernel)
10507 * ACTION "filter" must have a non-zero length region
10510 if (filter->action == PERF_ADDR_FILTER_ACTION_FILTER &&
10519 * For now, we only support file-based filters
10520 * in per-task events; doing so for CPU-wide
10521 * events requires additional context switching
10522 * trickery, since same object code will be
10523 * mapped at different virtual addresses in
10524 * different processes.
10527 if (!event->ctx->task)
10530 /* look up the path and grab its inode */
10531 ret = kern_path(filename, LOOKUP_FOLLOW,
10537 if (!filter->path.dentry ||
10538 !S_ISREG(d_inode(filter->path.dentry)
10542 event->addr_filters.nr_file_filters++;
10545 /* ready to consume more filters */
10546 state = IF_STATE_ACTION;
10551 if (state != IF_STATE_ACTION)
10561 free_filters_list(filters);
10568 perf_event_set_addr_filter(struct perf_event *event, char *filter_str)
10570 LIST_HEAD(filters);
10574 * Since this is called in perf_ioctl() path, we're already holding
10577 lockdep_assert_held(&event->ctx->mutex);
10579 if (WARN_ON_ONCE(event->parent))
10582 ret = perf_event_parse_addr_filter(event, filter_str, &filters);
10584 goto fail_clear_files;
10586 ret = event->pmu->addr_filters_validate(&filters);
10588 goto fail_free_filters;
10590 /* remove existing filters, if any */
10591 perf_addr_filters_splice(event, &filters);
10593 /* install new filters */
10594 perf_event_for_each_child(event, perf_event_addr_filters_apply);
10599 free_filters_list(&filters);
10602 event->addr_filters.nr_file_filters = 0;
10607 static int perf_event_set_filter(struct perf_event *event, void __user *arg)
10612 filter_str = strndup_user(arg, PAGE_SIZE);
10613 if (IS_ERR(filter_str))
10614 return PTR_ERR(filter_str);
10616 #ifdef CONFIG_EVENT_TRACING
10617 if (perf_event_is_tracing(event)) {
10618 struct perf_event_context *ctx = event->ctx;
10621 * Beware, here be dragons!!
10623 * the tracepoint muck will deadlock against ctx->mutex, but
10624 * the tracepoint stuff does not actually need it. So
10625 * temporarily drop ctx->mutex. As per perf_event_ctx_lock() we
10626 * already have a reference on ctx.
10628 * This can result in event getting moved to a different ctx,
10629 * but that does not affect the tracepoint state.
10631 mutex_unlock(&ctx->mutex);
10632 ret = ftrace_profile_set_filter(event, event->attr.config, filter_str);
10633 mutex_lock(&ctx->mutex);
10636 if (has_addr_filter(event))
10637 ret = perf_event_set_addr_filter(event, filter_str);
10644 * hrtimer based swevent callback
10647 static enum hrtimer_restart perf_swevent_hrtimer(struct hrtimer *hrtimer)
10649 enum hrtimer_restart ret = HRTIMER_RESTART;
10650 struct perf_sample_data data;
10651 struct pt_regs *regs;
10652 struct perf_event *event;
10655 event = container_of(hrtimer, struct perf_event, hw.hrtimer);
10657 if (event->state != PERF_EVENT_STATE_ACTIVE)
10658 return HRTIMER_NORESTART;
10660 event->pmu->read(event);
10662 perf_sample_data_init(&data, 0, event->hw.last_period);
10663 regs = get_irq_regs();
10665 if (regs && !perf_exclude_event(event, regs)) {
10666 if (!(event->attr.exclude_idle && is_idle_task(current)))
10667 if (__perf_event_overflow(event, 1, &data, regs))
10668 ret = HRTIMER_NORESTART;
10671 period = max_t(u64, 10000, event->hw.sample_period);
10672 hrtimer_forward_now(hrtimer, ns_to_ktime(period));
10677 static void perf_swevent_start_hrtimer(struct perf_event *event)
10679 struct hw_perf_event *hwc = &event->hw;
10682 if (!is_sampling_event(event))
10685 period = local64_read(&hwc->period_left);
10690 local64_set(&hwc->period_left, 0);
10692 period = max_t(u64, 10000, hwc->sample_period);
10694 hrtimer_start(&hwc->hrtimer, ns_to_ktime(period),
10695 HRTIMER_MODE_REL_PINNED_HARD);
10698 static void perf_swevent_cancel_hrtimer(struct perf_event *event)
10700 struct hw_perf_event *hwc = &event->hw;
10702 if (is_sampling_event(event)) {
10703 ktime_t remaining = hrtimer_get_remaining(&hwc->hrtimer);
10704 local64_set(&hwc->period_left, ktime_to_ns(remaining));
10706 hrtimer_cancel(&hwc->hrtimer);
10710 static void perf_swevent_init_hrtimer(struct perf_event *event)
10712 struct hw_perf_event *hwc = &event->hw;
10714 if (!is_sampling_event(event))
10717 hrtimer_init(&hwc->hrtimer, CLOCK_MONOTONIC, HRTIMER_MODE_REL_HARD);
10718 hwc->hrtimer.function = perf_swevent_hrtimer;
10721 * Since hrtimers have a fixed rate, we can do a static freq->period
10722 * mapping and avoid the whole period adjust feedback stuff.
10724 if (event->attr.freq) {
10725 long freq = event->attr.sample_freq;
10727 event->attr.sample_period = NSEC_PER_SEC / freq;
10728 hwc->sample_period = event->attr.sample_period;
10729 local64_set(&hwc->period_left, hwc->sample_period);
10730 hwc->last_period = hwc->sample_period;
10731 event->attr.freq = 0;
10736 * Software event: cpu wall time clock
10739 static void cpu_clock_event_update(struct perf_event *event)
10744 now = local_clock();
10745 prev = local64_xchg(&event->hw.prev_count, now);
10746 local64_add(now - prev, &event->count);
10749 static void cpu_clock_event_start(struct perf_event *event, int flags)
10751 local64_set(&event->hw.prev_count, local_clock());
10752 perf_swevent_start_hrtimer(event);
10755 static void cpu_clock_event_stop(struct perf_event *event, int flags)
10757 perf_swevent_cancel_hrtimer(event);
10758 cpu_clock_event_update(event);
10761 static int cpu_clock_event_add(struct perf_event *event, int flags)
10763 if (flags & PERF_EF_START)
10764 cpu_clock_event_start(event, flags);
10765 perf_event_update_userpage(event);
10770 static void cpu_clock_event_del(struct perf_event *event, int flags)
10772 cpu_clock_event_stop(event, flags);
10775 static void cpu_clock_event_read(struct perf_event *event)
10777 cpu_clock_event_update(event);
10780 static int cpu_clock_event_init(struct perf_event *event)
10782 if (event->attr.type != PERF_TYPE_SOFTWARE)
10785 if (event->attr.config != PERF_COUNT_SW_CPU_CLOCK)
10789 * no branch sampling for software events
10791 if (has_branch_stack(event))
10792 return -EOPNOTSUPP;
10794 perf_swevent_init_hrtimer(event);
10799 static struct pmu perf_cpu_clock = {
10800 .task_ctx_nr = perf_sw_context,
10802 .capabilities = PERF_PMU_CAP_NO_NMI,
10804 .event_init = cpu_clock_event_init,
10805 .add = cpu_clock_event_add,
10806 .del = cpu_clock_event_del,
10807 .start = cpu_clock_event_start,
10808 .stop = cpu_clock_event_stop,
10809 .read = cpu_clock_event_read,
10813 * Software event: task time clock
10816 static void task_clock_event_update(struct perf_event *event, u64 now)
10821 prev = local64_xchg(&event->hw.prev_count, now);
10822 delta = now - prev;
10823 local64_add(delta, &event->count);
10826 static void task_clock_event_start(struct perf_event *event, int flags)
10828 local64_set(&event->hw.prev_count, event->ctx->time);
10829 perf_swevent_start_hrtimer(event);
10832 static void task_clock_event_stop(struct perf_event *event, int flags)
10834 perf_swevent_cancel_hrtimer(event);
10835 task_clock_event_update(event, event->ctx->time);
10838 static int task_clock_event_add(struct perf_event *event, int flags)
10840 if (flags & PERF_EF_START)
10841 task_clock_event_start(event, flags);
10842 perf_event_update_userpage(event);
10847 static void task_clock_event_del(struct perf_event *event, int flags)
10849 task_clock_event_stop(event, PERF_EF_UPDATE);
10852 static void task_clock_event_read(struct perf_event *event)
10854 u64 now = perf_clock();
10855 u64 delta = now - event->ctx->timestamp;
10856 u64 time = event->ctx->time + delta;
10858 task_clock_event_update(event, time);
10861 static int task_clock_event_init(struct perf_event *event)
10863 if (event->attr.type != PERF_TYPE_SOFTWARE)
10866 if (event->attr.config != PERF_COUNT_SW_TASK_CLOCK)
10870 * no branch sampling for software events
10872 if (has_branch_stack(event))
10873 return -EOPNOTSUPP;
10875 perf_swevent_init_hrtimer(event);
10880 static struct pmu perf_task_clock = {
10881 .task_ctx_nr = perf_sw_context,
10883 .capabilities = PERF_PMU_CAP_NO_NMI,
10885 .event_init = task_clock_event_init,
10886 .add = task_clock_event_add,
10887 .del = task_clock_event_del,
10888 .start = task_clock_event_start,
10889 .stop = task_clock_event_stop,
10890 .read = task_clock_event_read,
10893 static void perf_pmu_nop_void(struct pmu *pmu)
10897 static void perf_pmu_nop_txn(struct pmu *pmu, unsigned int flags)
10901 static int perf_pmu_nop_int(struct pmu *pmu)
10906 static int perf_event_nop_int(struct perf_event *event, u64 value)
10911 static DEFINE_PER_CPU(unsigned int, nop_txn_flags);
10913 static void perf_pmu_start_txn(struct pmu *pmu, unsigned int flags)
10915 __this_cpu_write(nop_txn_flags, flags);
10917 if (flags & ~PERF_PMU_TXN_ADD)
10920 perf_pmu_disable(pmu);
10923 static int perf_pmu_commit_txn(struct pmu *pmu)
10925 unsigned int flags = __this_cpu_read(nop_txn_flags);
10927 __this_cpu_write(nop_txn_flags, 0);
10929 if (flags & ~PERF_PMU_TXN_ADD)
10932 perf_pmu_enable(pmu);
10936 static void perf_pmu_cancel_txn(struct pmu *pmu)
10938 unsigned int flags = __this_cpu_read(nop_txn_flags);
10940 __this_cpu_write(nop_txn_flags, 0);
10942 if (flags & ~PERF_PMU_TXN_ADD)
10945 perf_pmu_enable(pmu);
10948 static int perf_event_idx_default(struct perf_event *event)
10954 * Ensures all contexts with the same task_ctx_nr have the same
10955 * pmu_cpu_context too.
10957 static struct perf_cpu_context __percpu *find_pmu_context(int ctxn)
10964 list_for_each_entry(pmu, &pmus, entry) {
10965 if (pmu->task_ctx_nr == ctxn)
10966 return pmu->pmu_cpu_context;
10972 static void free_pmu_context(struct pmu *pmu)
10975 * Static contexts such as perf_sw_context have a global lifetime
10976 * and may be shared between different PMUs. Avoid freeing them
10977 * when a single PMU is going away.
10979 if (pmu->task_ctx_nr > perf_invalid_context)
10982 free_percpu(pmu->pmu_cpu_context);
10986 * Let userspace know that this PMU supports address range filtering:
10988 static ssize_t nr_addr_filters_show(struct device *dev,
10989 struct device_attribute *attr,
10992 struct pmu *pmu = dev_get_drvdata(dev);
10994 return snprintf(page, PAGE_SIZE - 1, "%d\n", pmu->nr_addr_filters);
10996 DEVICE_ATTR_RO(nr_addr_filters);
10998 static struct idr pmu_idr;
11001 type_show(struct device *dev, struct device_attribute *attr, char *page)
11003 struct pmu *pmu = dev_get_drvdata(dev);
11005 return snprintf(page, PAGE_SIZE-1, "%d\n", pmu->type);
11007 static DEVICE_ATTR_RO(type);
11010 perf_event_mux_interval_ms_show(struct device *dev,
11011 struct device_attribute *attr,
11014 struct pmu *pmu = dev_get_drvdata(dev);
11016 return snprintf(page, PAGE_SIZE-1, "%d\n", pmu->hrtimer_interval_ms);
11019 static DEFINE_MUTEX(mux_interval_mutex);
11022 perf_event_mux_interval_ms_store(struct device *dev,
11023 struct device_attribute *attr,
11024 const char *buf, size_t count)
11026 struct pmu *pmu = dev_get_drvdata(dev);
11027 int timer, cpu, ret;
11029 ret = kstrtoint(buf, 0, &timer);
11036 /* same value, noting to do */
11037 if (timer == pmu->hrtimer_interval_ms)
11040 mutex_lock(&mux_interval_mutex);
11041 pmu->hrtimer_interval_ms = timer;
11043 /* update all cpuctx for this PMU */
11045 for_each_online_cpu(cpu) {
11046 struct perf_cpu_context *cpuctx;
11047 cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
11048 cpuctx->hrtimer_interval = ns_to_ktime(NSEC_PER_MSEC * timer);
11050 cpu_function_call(cpu,
11051 (remote_function_f)perf_mux_hrtimer_restart, cpuctx);
11053 cpus_read_unlock();
11054 mutex_unlock(&mux_interval_mutex);
11058 static DEVICE_ATTR_RW(perf_event_mux_interval_ms);
11060 static struct attribute *pmu_dev_attrs[] = {
11061 &dev_attr_type.attr,
11062 &dev_attr_perf_event_mux_interval_ms.attr,
11065 ATTRIBUTE_GROUPS(pmu_dev);
11067 static int pmu_bus_running;
11068 static struct bus_type pmu_bus = {
11069 .name = "event_source",
11070 .dev_groups = pmu_dev_groups,
11073 static void pmu_dev_release(struct device *dev)
11078 static int pmu_dev_alloc(struct pmu *pmu)
11082 pmu->dev = kzalloc(sizeof(struct device), GFP_KERNEL);
11086 pmu->dev->groups = pmu->attr_groups;
11087 device_initialize(pmu->dev);
11088 ret = dev_set_name(pmu->dev, "%s", pmu->name);
11092 dev_set_drvdata(pmu->dev, pmu);
11093 pmu->dev->bus = &pmu_bus;
11094 pmu->dev->release = pmu_dev_release;
11095 ret = device_add(pmu->dev);
11099 /* For PMUs with address filters, throw in an extra attribute: */
11100 if (pmu->nr_addr_filters)
11101 ret = device_create_file(pmu->dev, &dev_attr_nr_addr_filters);
11106 if (pmu->attr_update)
11107 ret = sysfs_update_groups(&pmu->dev->kobj, pmu->attr_update);
11116 device_del(pmu->dev);
11119 put_device(pmu->dev);
11123 static struct lock_class_key cpuctx_mutex;
11124 static struct lock_class_key cpuctx_lock;
11126 int perf_pmu_register(struct pmu *pmu, const char *name, int type)
11128 int cpu, ret, max = PERF_TYPE_MAX;
11130 mutex_lock(&pmus_lock);
11132 pmu->pmu_disable_count = alloc_percpu(int);
11133 if (!pmu->pmu_disable_count)
11141 if (type != PERF_TYPE_SOFTWARE) {
11145 ret = idr_alloc(&pmu_idr, pmu, max, 0, GFP_KERNEL);
11149 WARN_ON(type >= 0 && ret != type);
11155 if (pmu_bus_running) {
11156 ret = pmu_dev_alloc(pmu);
11162 if (pmu->task_ctx_nr == perf_hw_context) {
11163 static int hw_context_taken = 0;
11166 * Other than systems with heterogeneous CPUs, it never makes
11167 * sense for two PMUs to share perf_hw_context. PMUs which are
11168 * uncore must use perf_invalid_context.
11170 if (WARN_ON_ONCE(hw_context_taken &&
11171 !(pmu->capabilities & PERF_PMU_CAP_HETEROGENEOUS_CPUS)))
11172 pmu->task_ctx_nr = perf_invalid_context;
11174 hw_context_taken = 1;
11177 pmu->pmu_cpu_context = find_pmu_context(pmu->task_ctx_nr);
11178 if (pmu->pmu_cpu_context)
11179 goto got_cpu_context;
11182 pmu->pmu_cpu_context = alloc_percpu(struct perf_cpu_context);
11183 if (!pmu->pmu_cpu_context)
11186 for_each_possible_cpu(cpu) {
11187 struct perf_cpu_context *cpuctx;
11189 cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
11190 __perf_event_init_context(&cpuctx->ctx);
11191 lockdep_set_class(&cpuctx->ctx.mutex, &cpuctx_mutex);
11192 lockdep_set_class(&cpuctx->ctx.lock, &cpuctx_lock);
11193 cpuctx->ctx.pmu = pmu;
11194 cpuctx->online = cpumask_test_cpu(cpu, perf_online_mask);
11196 __perf_mux_hrtimer_init(cpuctx, cpu);
11198 cpuctx->heap_size = ARRAY_SIZE(cpuctx->heap_default);
11199 cpuctx->heap = cpuctx->heap_default;
11203 if (!pmu->start_txn) {
11204 if (pmu->pmu_enable) {
11206 * If we have pmu_enable/pmu_disable calls, install
11207 * transaction stubs that use that to try and batch
11208 * hardware accesses.
11210 pmu->start_txn = perf_pmu_start_txn;
11211 pmu->commit_txn = perf_pmu_commit_txn;
11212 pmu->cancel_txn = perf_pmu_cancel_txn;
11214 pmu->start_txn = perf_pmu_nop_txn;
11215 pmu->commit_txn = perf_pmu_nop_int;
11216 pmu->cancel_txn = perf_pmu_nop_void;
11220 if (!pmu->pmu_enable) {
11221 pmu->pmu_enable = perf_pmu_nop_void;
11222 pmu->pmu_disable = perf_pmu_nop_void;
11225 if (!pmu->check_period)
11226 pmu->check_period = perf_event_nop_int;
11228 if (!pmu->event_idx)
11229 pmu->event_idx = perf_event_idx_default;
11232 * Ensure the TYPE_SOFTWARE PMUs are at the head of the list,
11233 * since these cannot be in the IDR. This way the linear search
11234 * is fast, provided a valid software event is provided.
11236 if (type == PERF_TYPE_SOFTWARE || !name)
11237 list_add_rcu(&pmu->entry, &pmus);
11239 list_add_tail_rcu(&pmu->entry, &pmus);
11241 atomic_set(&pmu->exclusive_cnt, 0);
11244 mutex_unlock(&pmus_lock);
11249 device_del(pmu->dev);
11250 put_device(pmu->dev);
11253 if (pmu->type != PERF_TYPE_SOFTWARE)
11254 idr_remove(&pmu_idr, pmu->type);
11257 free_percpu(pmu->pmu_disable_count);
11260 EXPORT_SYMBOL_GPL(perf_pmu_register);
11262 void perf_pmu_unregister(struct pmu *pmu)
11264 mutex_lock(&pmus_lock);
11265 list_del_rcu(&pmu->entry);
11268 * We dereference the pmu list under both SRCU and regular RCU, so
11269 * synchronize against both of those.
11271 synchronize_srcu(&pmus_srcu);
11274 free_percpu(pmu->pmu_disable_count);
11275 if (pmu->type != PERF_TYPE_SOFTWARE)
11276 idr_remove(&pmu_idr, pmu->type);
11277 if (pmu_bus_running) {
11278 if (pmu->nr_addr_filters)
11279 device_remove_file(pmu->dev, &dev_attr_nr_addr_filters);
11280 device_del(pmu->dev);
11281 put_device(pmu->dev);
11283 free_pmu_context(pmu);
11284 mutex_unlock(&pmus_lock);
11286 EXPORT_SYMBOL_GPL(perf_pmu_unregister);
11288 static inline bool has_extended_regs(struct perf_event *event)
11290 return (event->attr.sample_regs_user & PERF_REG_EXTENDED_MASK) ||
11291 (event->attr.sample_regs_intr & PERF_REG_EXTENDED_MASK);
11294 static int perf_try_init_event(struct pmu *pmu, struct perf_event *event)
11296 struct perf_event_context *ctx = NULL;
11299 if (!try_module_get(pmu->module))
11303 * A number of pmu->event_init() methods iterate the sibling_list to,
11304 * for example, validate if the group fits on the PMU. Therefore,
11305 * if this is a sibling event, acquire the ctx->mutex to protect
11306 * the sibling_list.
11308 if (event->group_leader != event && pmu->task_ctx_nr != perf_sw_context) {
11310 * This ctx->mutex can nest when we're called through
11311 * inheritance. See the perf_event_ctx_lock_nested() comment.
11313 ctx = perf_event_ctx_lock_nested(event->group_leader,
11314 SINGLE_DEPTH_NESTING);
11319 ret = pmu->event_init(event);
11322 perf_event_ctx_unlock(event->group_leader, ctx);
11325 if (!(pmu->capabilities & PERF_PMU_CAP_EXTENDED_REGS) &&
11326 has_extended_regs(event))
11329 if (pmu->capabilities & PERF_PMU_CAP_NO_EXCLUDE &&
11330 event_has_any_exclude_flag(event))
11333 if (ret && event->destroy)
11334 event->destroy(event);
11338 module_put(pmu->module);
11343 static struct pmu *perf_init_event(struct perf_event *event)
11345 bool extended_type = false;
11346 int idx, type, ret;
11349 idx = srcu_read_lock(&pmus_srcu);
11351 /* Try parent's PMU first: */
11352 if (event->parent && event->parent->pmu) {
11353 pmu = event->parent->pmu;
11354 ret = perf_try_init_event(pmu, event);
11360 * PERF_TYPE_HARDWARE and PERF_TYPE_HW_CACHE
11361 * are often aliases for PERF_TYPE_RAW.
11363 type = event->attr.type;
11364 if (type == PERF_TYPE_HARDWARE || type == PERF_TYPE_HW_CACHE) {
11365 type = event->attr.config >> PERF_PMU_TYPE_SHIFT;
11367 type = PERF_TYPE_RAW;
11369 extended_type = true;
11370 event->attr.config &= PERF_HW_EVENT_MASK;
11376 pmu = idr_find(&pmu_idr, type);
11379 if (event->attr.type != type && type != PERF_TYPE_RAW &&
11380 !(pmu->capabilities & PERF_PMU_CAP_EXTENDED_HW_TYPE))
11383 ret = perf_try_init_event(pmu, event);
11384 if (ret == -ENOENT && event->attr.type != type && !extended_type) {
11385 type = event->attr.type;
11390 pmu = ERR_PTR(ret);
11395 list_for_each_entry_rcu(pmu, &pmus, entry, lockdep_is_held(&pmus_srcu)) {
11396 ret = perf_try_init_event(pmu, event);
11400 if (ret != -ENOENT) {
11401 pmu = ERR_PTR(ret);
11406 pmu = ERR_PTR(-ENOENT);
11408 srcu_read_unlock(&pmus_srcu, idx);
11413 static void attach_sb_event(struct perf_event *event)
11415 struct pmu_event_list *pel = per_cpu_ptr(&pmu_sb_events, event->cpu);
11417 raw_spin_lock(&pel->lock);
11418 list_add_rcu(&event->sb_list, &pel->list);
11419 raw_spin_unlock(&pel->lock);
11423 * We keep a list of all !task (and therefore per-cpu) events
11424 * that need to receive side-band records.
11426 * This avoids having to scan all the various PMU per-cpu contexts
11427 * looking for them.
11429 static void account_pmu_sb_event(struct perf_event *event)
11431 if (is_sb_event(event))
11432 attach_sb_event(event);
11435 static void account_event_cpu(struct perf_event *event, int cpu)
11440 if (is_cgroup_event(event))
11441 atomic_inc(&per_cpu(perf_cgroup_events, cpu));
11444 /* Freq events need the tick to stay alive (see perf_event_task_tick). */
11445 static void account_freq_event_nohz(void)
11447 #ifdef CONFIG_NO_HZ_FULL
11448 /* Lock so we don't race with concurrent unaccount */
11449 spin_lock(&nr_freq_lock);
11450 if (atomic_inc_return(&nr_freq_events) == 1)
11451 tick_nohz_dep_set(TICK_DEP_BIT_PERF_EVENTS);
11452 spin_unlock(&nr_freq_lock);
11456 static void account_freq_event(void)
11458 if (tick_nohz_full_enabled())
11459 account_freq_event_nohz();
11461 atomic_inc(&nr_freq_events);
11465 static void account_event(struct perf_event *event)
11472 if (event->attach_state & (PERF_ATTACH_TASK | PERF_ATTACH_SCHED_CB))
11474 if (event->attr.mmap || event->attr.mmap_data)
11475 atomic_inc(&nr_mmap_events);
11476 if (event->attr.build_id)
11477 atomic_inc(&nr_build_id_events);
11478 if (event->attr.comm)
11479 atomic_inc(&nr_comm_events);
11480 if (event->attr.namespaces)
11481 atomic_inc(&nr_namespaces_events);
11482 if (event->attr.cgroup)
11483 atomic_inc(&nr_cgroup_events);
11484 if (event->attr.task)
11485 atomic_inc(&nr_task_events);
11486 if (event->attr.freq)
11487 account_freq_event();
11488 if (event->attr.context_switch) {
11489 atomic_inc(&nr_switch_events);
11492 if (has_branch_stack(event))
11494 if (is_cgroup_event(event))
11496 if (event->attr.ksymbol)
11497 atomic_inc(&nr_ksymbol_events);
11498 if (event->attr.bpf_event)
11499 atomic_inc(&nr_bpf_events);
11500 if (event->attr.text_poke)
11501 atomic_inc(&nr_text_poke_events);
11505 * We need the mutex here because static_branch_enable()
11506 * must complete *before* the perf_sched_count increment
11509 if (atomic_inc_not_zero(&perf_sched_count))
11512 mutex_lock(&perf_sched_mutex);
11513 if (!atomic_read(&perf_sched_count)) {
11514 static_branch_enable(&perf_sched_events);
11516 * Guarantee that all CPUs observe they key change and
11517 * call the perf scheduling hooks before proceeding to
11518 * install events that need them.
11523 * Now that we have waited for the sync_sched(), allow further
11524 * increments to by-pass the mutex.
11526 atomic_inc(&perf_sched_count);
11527 mutex_unlock(&perf_sched_mutex);
11531 account_event_cpu(event, event->cpu);
11533 account_pmu_sb_event(event);
11537 * Allocate and initialize an event structure
11539 static struct perf_event *
11540 perf_event_alloc(struct perf_event_attr *attr, int cpu,
11541 struct task_struct *task,
11542 struct perf_event *group_leader,
11543 struct perf_event *parent_event,
11544 perf_overflow_handler_t overflow_handler,
11545 void *context, int cgroup_fd)
11548 struct perf_event *event;
11549 struct hw_perf_event *hwc;
11550 long err = -EINVAL;
11553 if ((unsigned)cpu >= nr_cpu_ids) {
11554 if (!task || cpu != -1)
11555 return ERR_PTR(-EINVAL);
11557 if (attr->sigtrap && !task) {
11558 /* Requires a task: avoid signalling random tasks. */
11559 return ERR_PTR(-EINVAL);
11562 node = (cpu >= 0) ? cpu_to_node(cpu) : -1;
11563 event = kmem_cache_alloc_node(perf_event_cache, GFP_KERNEL | __GFP_ZERO,
11566 return ERR_PTR(-ENOMEM);
11569 * Single events are their own group leaders, with an
11570 * empty sibling list:
11573 group_leader = event;
11575 mutex_init(&event->child_mutex);
11576 INIT_LIST_HEAD(&event->child_list);
11578 INIT_LIST_HEAD(&event->event_entry);
11579 INIT_LIST_HEAD(&event->sibling_list);
11580 INIT_LIST_HEAD(&event->active_list);
11581 init_event_group(event);
11582 INIT_LIST_HEAD(&event->rb_entry);
11583 INIT_LIST_HEAD(&event->active_entry);
11584 INIT_LIST_HEAD(&event->addr_filters.list);
11585 INIT_HLIST_NODE(&event->hlist_entry);
11588 init_waitqueue_head(&event->waitq);
11589 event->pending_disable = -1;
11590 init_irq_work(&event->pending, perf_pending_event);
11592 mutex_init(&event->mmap_mutex);
11593 raw_spin_lock_init(&event->addr_filters.lock);
11595 atomic_long_set(&event->refcount, 1);
11597 event->attr = *attr;
11598 event->group_leader = group_leader;
11602 event->parent = parent_event;
11604 event->ns = get_pid_ns(task_active_pid_ns(current));
11605 event->id = atomic64_inc_return(&perf_event_id);
11607 event->state = PERF_EVENT_STATE_INACTIVE;
11609 if (event->attr.sigtrap)
11610 atomic_set(&event->event_limit, 1);
11613 event->attach_state = PERF_ATTACH_TASK;
11615 * XXX pmu::event_init needs to know what task to account to
11616 * and we cannot use the ctx information because we need the
11617 * pmu before we get a ctx.
11619 event->hw.target = get_task_struct(task);
11622 event->clock = &local_clock;
11624 event->clock = parent_event->clock;
11626 if (!overflow_handler && parent_event) {
11627 overflow_handler = parent_event->overflow_handler;
11628 context = parent_event->overflow_handler_context;
11629 #if defined(CONFIG_BPF_SYSCALL) && defined(CONFIG_EVENT_TRACING)
11630 if (overflow_handler == bpf_overflow_handler) {
11631 struct bpf_prog *prog = parent_event->prog;
11633 bpf_prog_inc(prog);
11634 event->prog = prog;
11635 event->orig_overflow_handler =
11636 parent_event->orig_overflow_handler;
11641 if (overflow_handler) {
11642 event->overflow_handler = overflow_handler;
11643 event->overflow_handler_context = context;
11644 } else if (is_write_backward(event)){
11645 event->overflow_handler = perf_event_output_backward;
11646 event->overflow_handler_context = NULL;
11648 event->overflow_handler = perf_event_output_forward;
11649 event->overflow_handler_context = NULL;
11652 perf_event__state_init(event);
11657 hwc->sample_period = attr->sample_period;
11658 if (attr->freq && attr->sample_freq)
11659 hwc->sample_period = 1;
11660 hwc->last_period = hwc->sample_period;
11662 local64_set(&hwc->period_left, hwc->sample_period);
11665 * We currently do not support PERF_SAMPLE_READ on inherited events.
11666 * See perf_output_read().
11668 if (attr->inherit && (attr->sample_type & PERF_SAMPLE_READ))
11671 if (!has_branch_stack(event))
11672 event->attr.branch_sample_type = 0;
11674 pmu = perf_init_event(event);
11676 err = PTR_ERR(pmu);
11681 * Disallow uncore-cgroup events, they don't make sense as the cgroup will
11682 * be different on other CPUs in the uncore mask.
11684 if (pmu->task_ctx_nr == perf_invalid_context && cgroup_fd != -1) {
11689 if (event->attr.aux_output &&
11690 !(pmu->capabilities & PERF_PMU_CAP_AUX_OUTPUT)) {
11695 if (cgroup_fd != -1) {
11696 err = perf_cgroup_connect(cgroup_fd, event, attr, group_leader);
11701 err = exclusive_event_init(event);
11705 if (has_addr_filter(event)) {
11706 event->addr_filter_ranges = kcalloc(pmu->nr_addr_filters,
11707 sizeof(struct perf_addr_filter_range),
11709 if (!event->addr_filter_ranges) {
11715 * Clone the parent's vma offsets: they are valid until exec()
11716 * even if the mm is not shared with the parent.
11718 if (event->parent) {
11719 struct perf_addr_filters_head *ifh = perf_event_addr_filters(event);
11721 raw_spin_lock_irq(&ifh->lock);
11722 memcpy(event->addr_filter_ranges,
11723 event->parent->addr_filter_ranges,
11724 pmu->nr_addr_filters * sizeof(struct perf_addr_filter_range));
11725 raw_spin_unlock_irq(&ifh->lock);
11728 /* force hw sync on the address filters */
11729 event->addr_filters_gen = 1;
11732 if (!event->parent) {
11733 if (event->attr.sample_type & PERF_SAMPLE_CALLCHAIN) {
11734 err = get_callchain_buffers(attr->sample_max_stack);
11736 goto err_addr_filters;
11740 err = security_perf_event_alloc(event);
11742 goto err_callchain_buffer;
11744 /* symmetric to unaccount_event() in _free_event() */
11745 account_event(event);
11749 err_callchain_buffer:
11750 if (!event->parent) {
11751 if (event->attr.sample_type & PERF_SAMPLE_CALLCHAIN)
11752 put_callchain_buffers();
11755 kfree(event->addr_filter_ranges);
11758 exclusive_event_destroy(event);
11761 if (is_cgroup_event(event))
11762 perf_detach_cgroup(event);
11763 if (event->destroy)
11764 event->destroy(event);
11765 module_put(pmu->module);
11768 put_pid_ns(event->ns);
11769 if (event->hw.target)
11770 put_task_struct(event->hw.target);
11771 kmem_cache_free(perf_event_cache, event);
11773 return ERR_PTR(err);
11776 static int perf_copy_attr(struct perf_event_attr __user *uattr,
11777 struct perf_event_attr *attr)
11782 /* Zero the full structure, so that a short copy will be nice. */
11783 memset(attr, 0, sizeof(*attr));
11785 ret = get_user(size, &uattr->size);
11789 /* ABI compatibility quirk: */
11791 size = PERF_ATTR_SIZE_VER0;
11792 if (size < PERF_ATTR_SIZE_VER0 || size > PAGE_SIZE)
11795 ret = copy_struct_from_user(attr, sizeof(*attr), uattr, size);
11804 if (attr->__reserved_1 || attr->__reserved_2 || attr->__reserved_3)
11807 if (attr->sample_type & ~(PERF_SAMPLE_MAX-1))
11810 if (attr->read_format & ~(PERF_FORMAT_MAX-1))
11813 if (attr->sample_type & PERF_SAMPLE_BRANCH_STACK) {
11814 u64 mask = attr->branch_sample_type;
11816 /* only using defined bits */
11817 if (mask & ~(PERF_SAMPLE_BRANCH_MAX-1))
11820 /* at least one branch bit must be set */
11821 if (!(mask & ~PERF_SAMPLE_BRANCH_PLM_ALL))
11824 /* propagate priv level, when not set for branch */
11825 if (!(mask & PERF_SAMPLE_BRANCH_PLM_ALL)) {
11827 /* exclude_kernel checked on syscall entry */
11828 if (!attr->exclude_kernel)
11829 mask |= PERF_SAMPLE_BRANCH_KERNEL;
11831 if (!attr->exclude_user)
11832 mask |= PERF_SAMPLE_BRANCH_USER;
11834 if (!attr->exclude_hv)
11835 mask |= PERF_SAMPLE_BRANCH_HV;
11837 * adjust user setting (for HW filter setup)
11839 attr->branch_sample_type = mask;
11841 /* privileged levels capture (kernel, hv): check permissions */
11842 if (mask & PERF_SAMPLE_BRANCH_PERM_PLM) {
11843 ret = perf_allow_kernel(attr);
11849 if (attr->sample_type & PERF_SAMPLE_REGS_USER) {
11850 ret = perf_reg_validate(attr->sample_regs_user);
11855 if (attr->sample_type & PERF_SAMPLE_STACK_USER) {
11856 if (!arch_perf_have_user_stack_dump())
11860 * We have __u32 type for the size, but so far
11861 * we can only use __u16 as maximum due to the
11862 * __u16 sample size limit.
11864 if (attr->sample_stack_user >= USHRT_MAX)
11866 else if (!IS_ALIGNED(attr->sample_stack_user, sizeof(u64)))
11870 if (!attr->sample_max_stack)
11871 attr->sample_max_stack = sysctl_perf_event_max_stack;
11873 if (attr->sample_type & PERF_SAMPLE_REGS_INTR)
11874 ret = perf_reg_validate(attr->sample_regs_intr);
11876 #ifndef CONFIG_CGROUP_PERF
11877 if (attr->sample_type & PERF_SAMPLE_CGROUP)
11880 if ((attr->sample_type & PERF_SAMPLE_WEIGHT) &&
11881 (attr->sample_type & PERF_SAMPLE_WEIGHT_STRUCT))
11884 if (!attr->inherit && attr->inherit_thread)
11887 if (attr->remove_on_exec && attr->enable_on_exec)
11890 if (attr->sigtrap && !attr->remove_on_exec)
11897 put_user(sizeof(*attr), &uattr->size);
11903 perf_event_set_output(struct perf_event *event, struct perf_event *output_event)
11905 struct perf_buffer *rb = NULL;
11911 /* don't allow circular references */
11912 if (event == output_event)
11916 * Don't allow cross-cpu buffers
11918 if (output_event->cpu != event->cpu)
11922 * If its not a per-cpu rb, it must be the same task.
11924 if (output_event->cpu == -1 && output_event->ctx != event->ctx)
11928 * Mixing clocks in the same buffer is trouble you don't need.
11930 if (output_event->clock != event->clock)
11934 * Either writing ring buffer from beginning or from end.
11935 * Mixing is not allowed.
11937 if (is_write_backward(output_event) != is_write_backward(event))
11941 * If both events generate aux data, they must be on the same PMU
11943 if (has_aux(event) && has_aux(output_event) &&
11944 event->pmu != output_event->pmu)
11948 mutex_lock(&event->mmap_mutex);
11949 /* Can't redirect output if we've got an active mmap() */
11950 if (atomic_read(&event->mmap_count))
11953 if (output_event) {
11954 /* get the rb we want to redirect to */
11955 rb = ring_buffer_get(output_event);
11960 ring_buffer_attach(event, rb);
11964 mutex_unlock(&event->mmap_mutex);
11970 static void mutex_lock_double(struct mutex *a, struct mutex *b)
11976 mutex_lock_nested(b, SINGLE_DEPTH_NESTING);
11979 static int perf_event_set_clock(struct perf_event *event, clockid_t clk_id)
11981 bool nmi_safe = false;
11984 case CLOCK_MONOTONIC:
11985 event->clock = &ktime_get_mono_fast_ns;
11989 case CLOCK_MONOTONIC_RAW:
11990 event->clock = &ktime_get_raw_fast_ns;
11994 case CLOCK_REALTIME:
11995 event->clock = &ktime_get_real_ns;
11998 case CLOCK_BOOTTIME:
11999 event->clock = &ktime_get_boottime_ns;
12003 event->clock = &ktime_get_clocktai_ns;
12010 if (!nmi_safe && !(event->pmu->capabilities & PERF_PMU_CAP_NO_NMI))
12017 * Variation on perf_event_ctx_lock_nested(), except we take two context
12020 static struct perf_event_context *
12021 __perf_event_ctx_lock_double(struct perf_event *group_leader,
12022 struct perf_event_context *ctx)
12024 struct perf_event_context *gctx;
12028 gctx = READ_ONCE(group_leader->ctx);
12029 if (!refcount_inc_not_zero(&gctx->refcount)) {
12035 mutex_lock_double(&gctx->mutex, &ctx->mutex);
12037 if (group_leader->ctx != gctx) {
12038 mutex_unlock(&ctx->mutex);
12039 mutex_unlock(&gctx->mutex);
12048 perf_check_permission(struct perf_event_attr *attr, struct task_struct *task)
12050 unsigned int ptrace_mode = PTRACE_MODE_READ_REALCREDS;
12051 bool is_capable = perfmon_capable();
12053 if (attr->sigtrap) {
12055 * perf_event_attr::sigtrap sends signals to the other task.
12056 * Require the current task to also have CAP_KILL.
12059 is_capable &= ns_capable(__task_cred(task)->user_ns, CAP_KILL);
12063 * If the required capabilities aren't available, checks for
12064 * ptrace permissions: upgrade to ATTACH, since sending signals
12065 * can effectively change the target task.
12067 ptrace_mode = PTRACE_MODE_ATTACH_REALCREDS;
12071 * Preserve ptrace permission check for backwards compatibility. The
12072 * ptrace check also includes checks that the current task and other
12073 * task have matching uids, and is therefore not done here explicitly.
12075 return is_capable || ptrace_may_access(task, ptrace_mode);
12079 * sys_perf_event_open - open a performance event, associate it to a task/cpu
12081 * @attr_uptr: event_id type attributes for monitoring/sampling
12084 * @group_fd: group leader event fd
12085 * @flags: perf event open flags
12087 SYSCALL_DEFINE5(perf_event_open,
12088 struct perf_event_attr __user *, attr_uptr,
12089 pid_t, pid, int, cpu, int, group_fd, unsigned long, flags)
12091 struct perf_event *group_leader = NULL, *output_event = NULL;
12092 struct perf_event *event, *sibling;
12093 struct perf_event_attr attr;
12094 struct perf_event_context *ctx, *gctx;
12095 struct file *event_file = NULL;
12096 struct fd group = {NULL, 0};
12097 struct task_struct *task = NULL;
12100 int move_group = 0;
12102 int f_flags = O_RDWR;
12103 int cgroup_fd = -1;
12105 /* for future expandability... */
12106 if (flags & ~PERF_FLAG_ALL)
12109 /* Do we allow access to perf_event_open(2) ? */
12110 err = security_perf_event_open(&attr, PERF_SECURITY_OPEN);
12114 err = perf_copy_attr(attr_uptr, &attr);
12118 if (!attr.exclude_kernel) {
12119 err = perf_allow_kernel(&attr);
12124 if (attr.namespaces) {
12125 if (!perfmon_capable())
12130 if (attr.sample_freq > sysctl_perf_event_sample_rate)
12133 if (attr.sample_period & (1ULL << 63))
12137 /* Only privileged users can get physical addresses */
12138 if ((attr.sample_type & PERF_SAMPLE_PHYS_ADDR)) {
12139 err = perf_allow_kernel(&attr);
12144 /* REGS_INTR can leak data, lockdown must prevent this */
12145 if (attr.sample_type & PERF_SAMPLE_REGS_INTR) {
12146 err = security_locked_down(LOCKDOWN_PERF);
12152 * In cgroup mode, the pid argument is used to pass the fd
12153 * opened to the cgroup directory in cgroupfs. The cpu argument
12154 * designates the cpu on which to monitor threads from that
12157 if ((flags & PERF_FLAG_PID_CGROUP) && (pid == -1 || cpu == -1))
12160 if (flags & PERF_FLAG_FD_CLOEXEC)
12161 f_flags |= O_CLOEXEC;
12163 event_fd = get_unused_fd_flags(f_flags);
12167 if (group_fd != -1) {
12168 err = perf_fget_light(group_fd, &group);
12171 group_leader = group.file->private_data;
12172 if (flags & PERF_FLAG_FD_OUTPUT)
12173 output_event = group_leader;
12174 if (flags & PERF_FLAG_FD_NO_GROUP)
12175 group_leader = NULL;
12178 if (pid != -1 && !(flags & PERF_FLAG_PID_CGROUP)) {
12179 task = find_lively_task_by_vpid(pid);
12180 if (IS_ERR(task)) {
12181 err = PTR_ERR(task);
12186 if (task && group_leader &&
12187 group_leader->attr.inherit != attr.inherit) {
12192 if (flags & PERF_FLAG_PID_CGROUP)
12195 event = perf_event_alloc(&attr, cpu, task, group_leader, NULL,
12196 NULL, NULL, cgroup_fd);
12197 if (IS_ERR(event)) {
12198 err = PTR_ERR(event);
12202 if (is_sampling_event(event)) {
12203 if (event->pmu->capabilities & PERF_PMU_CAP_NO_INTERRUPT) {
12210 * Special case software events and allow them to be part of
12211 * any hardware group.
12215 if (attr.use_clockid) {
12216 err = perf_event_set_clock(event, attr.clockid);
12221 if (pmu->task_ctx_nr == perf_sw_context)
12222 event->event_caps |= PERF_EV_CAP_SOFTWARE;
12224 if (group_leader) {
12225 if (is_software_event(event) &&
12226 !in_software_context(group_leader)) {
12228 * If the event is a sw event, but the group_leader
12229 * is on hw context.
12231 * Allow the addition of software events to hw
12232 * groups, this is safe because software events
12233 * never fail to schedule.
12235 pmu = group_leader->ctx->pmu;
12236 } else if (!is_software_event(event) &&
12237 is_software_event(group_leader) &&
12238 (group_leader->group_caps & PERF_EV_CAP_SOFTWARE)) {
12240 * In case the group is a pure software group, and we
12241 * try to add a hardware event, move the whole group to
12242 * the hardware context.
12249 * Get the target context (task or percpu):
12251 ctx = find_get_context(pmu, task, event);
12253 err = PTR_ERR(ctx);
12258 * Look up the group leader (we will attach this event to it):
12260 if (group_leader) {
12264 * Do not allow a recursive hierarchy (this new sibling
12265 * becoming part of another group-sibling):
12267 if (group_leader->group_leader != group_leader)
12270 /* All events in a group should have the same clock */
12271 if (group_leader->clock != event->clock)
12275 * Make sure we're both events for the same CPU;
12276 * grouping events for different CPUs is broken; since
12277 * you can never concurrently schedule them anyhow.
12279 if (group_leader->cpu != event->cpu)
12283 * Make sure we're both on the same task, or both
12286 if (group_leader->ctx->task != ctx->task)
12290 * Do not allow to attach to a group in a different task
12291 * or CPU context. If we're moving SW events, we'll fix
12292 * this up later, so allow that.
12294 if (!move_group && group_leader->ctx != ctx)
12298 * Only a group leader can be exclusive or pinned
12300 if (attr.exclusive || attr.pinned)
12304 if (output_event) {
12305 err = perf_event_set_output(event, output_event);
12310 event_file = anon_inode_getfile("[perf_event]", &perf_fops, event,
12312 if (IS_ERR(event_file)) {
12313 err = PTR_ERR(event_file);
12319 err = down_read_interruptible(&task->signal->exec_update_lock);
12324 * We must hold exec_update_lock across this and any potential
12325 * perf_install_in_context() call for this new event to
12326 * serialize against exec() altering our credentials (and the
12327 * perf_event_exit_task() that could imply).
12330 if (!perf_check_permission(&attr, task))
12335 gctx = __perf_event_ctx_lock_double(group_leader, ctx);
12337 if (gctx->task == TASK_TOMBSTONE) {
12343 * Check if we raced against another sys_perf_event_open() call
12344 * moving the software group underneath us.
12346 if (!(group_leader->group_caps & PERF_EV_CAP_SOFTWARE)) {
12348 * If someone moved the group out from under us, check
12349 * if this new event wound up on the same ctx, if so
12350 * its the regular !move_group case, otherwise fail.
12356 perf_event_ctx_unlock(group_leader, gctx);
12362 * Failure to create exclusive events returns -EBUSY.
12365 if (!exclusive_event_installable(group_leader, ctx))
12368 for_each_sibling_event(sibling, group_leader) {
12369 if (!exclusive_event_installable(sibling, ctx))
12373 mutex_lock(&ctx->mutex);
12376 if (ctx->task == TASK_TOMBSTONE) {
12381 if (!perf_event_validate_size(event)) {
12388 * Check if the @cpu we're creating an event for is online.
12390 * We use the perf_cpu_context::ctx::mutex to serialize against
12391 * the hotplug notifiers. See perf_event_{init,exit}_cpu().
12393 struct perf_cpu_context *cpuctx =
12394 container_of(ctx, struct perf_cpu_context, ctx);
12396 if (!cpuctx->online) {
12402 if (perf_need_aux_event(event) && !perf_get_aux_event(event, group_leader)) {
12408 * Must be under the same ctx::mutex as perf_install_in_context(),
12409 * because we need to serialize with concurrent event creation.
12411 if (!exclusive_event_installable(event, ctx)) {
12416 WARN_ON_ONCE(ctx->parent_ctx);
12419 * This is the point on no return; we cannot fail hereafter. This is
12420 * where we start modifying current state.
12425 * See perf_event_ctx_lock() for comments on the details
12426 * of swizzling perf_event::ctx.
12428 perf_remove_from_context(group_leader, 0);
12431 for_each_sibling_event(sibling, group_leader) {
12432 perf_remove_from_context(sibling, 0);
12437 * Wait for everybody to stop referencing the events through
12438 * the old lists, before installing it on new lists.
12443 * Install the group siblings before the group leader.
12445 * Because a group leader will try and install the entire group
12446 * (through the sibling list, which is still in-tact), we can
12447 * end up with siblings installed in the wrong context.
12449 * By installing siblings first we NO-OP because they're not
12450 * reachable through the group lists.
12452 for_each_sibling_event(sibling, group_leader) {
12453 perf_event__state_init(sibling);
12454 perf_install_in_context(ctx, sibling, sibling->cpu);
12459 * Removing from the context ends up with disabled
12460 * event. What we want here is event in the initial
12461 * startup state, ready to be add into new context.
12463 perf_event__state_init(group_leader);
12464 perf_install_in_context(ctx, group_leader, group_leader->cpu);
12469 * Precalculate sample_data sizes; do while holding ctx::mutex such
12470 * that we're serialized against further additions and before
12471 * perf_install_in_context() which is the point the event is active and
12472 * can use these values.
12474 perf_event__header_size(event);
12475 perf_event__id_header_size(event);
12477 event->owner = current;
12479 perf_install_in_context(ctx, event, event->cpu);
12480 perf_unpin_context(ctx);
12483 perf_event_ctx_unlock(group_leader, gctx);
12484 mutex_unlock(&ctx->mutex);
12487 up_read(&task->signal->exec_update_lock);
12488 put_task_struct(task);
12491 mutex_lock(¤t->perf_event_mutex);
12492 list_add_tail(&event->owner_entry, ¤t->perf_event_list);
12493 mutex_unlock(¤t->perf_event_mutex);
12496 * Drop the reference on the group_event after placing the
12497 * new event on the sibling_list. This ensures destruction
12498 * of the group leader will find the pointer to itself in
12499 * perf_group_detach().
12502 fd_install(event_fd, event_file);
12507 perf_event_ctx_unlock(group_leader, gctx);
12508 mutex_unlock(&ctx->mutex);
12511 up_read(&task->signal->exec_update_lock);
12515 perf_unpin_context(ctx);
12519 * If event_file is set, the fput() above will have called ->release()
12520 * and that will take care of freeing the event.
12526 put_task_struct(task);
12530 put_unused_fd(event_fd);
12535 * perf_event_create_kernel_counter
12537 * @attr: attributes of the counter to create
12538 * @cpu: cpu in which the counter is bound
12539 * @task: task to profile (NULL for percpu)
12540 * @overflow_handler: callback to trigger when we hit the event
12541 * @context: context data could be used in overflow_handler callback
12543 struct perf_event *
12544 perf_event_create_kernel_counter(struct perf_event_attr *attr, int cpu,
12545 struct task_struct *task,
12546 perf_overflow_handler_t overflow_handler,
12549 struct perf_event_context *ctx;
12550 struct perf_event *event;
12554 * Grouping is not supported for kernel events, neither is 'AUX',
12555 * make sure the caller's intentions are adjusted.
12557 if (attr->aux_output)
12558 return ERR_PTR(-EINVAL);
12560 event = perf_event_alloc(attr, cpu, task, NULL, NULL,
12561 overflow_handler, context, -1);
12562 if (IS_ERR(event)) {
12563 err = PTR_ERR(event);
12567 /* Mark owner so we could distinguish it from user events. */
12568 event->owner = TASK_TOMBSTONE;
12571 * Get the target context (task or percpu):
12573 ctx = find_get_context(event->pmu, task, event);
12575 err = PTR_ERR(ctx);
12579 WARN_ON_ONCE(ctx->parent_ctx);
12580 mutex_lock(&ctx->mutex);
12581 if (ctx->task == TASK_TOMBSTONE) {
12588 * Check if the @cpu we're creating an event for is online.
12590 * We use the perf_cpu_context::ctx::mutex to serialize against
12591 * the hotplug notifiers. See perf_event_{init,exit}_cpu().
12593 struct perf_cpu_context *cpuctx =
12594 container_of(ctx, struct perf_cpu_context, ctx);
12595 if (!cpuctx->online) {
12601 if (!exclusive_event_installable(event, ctx)) {
12606 perf_install_in_context(ctx, event, event->cpu);
12607 perf_unpin_context(ctx);
12608 mutex_unlock(&ctx->mutex);
12613 mutex_unlock(&ctx->mutex);
12614 perf_unpin_context(ctx);
12619 return ERR_PTR(err);
12621 EXPORT_SYMBOL_GPL(perf_event_create_kernel_counter);
12623 void perf_pmu_migrate_context(struct pmu *pmu, int src_cpu, int dst_cpu)
12625 struct perf_event_context *src_ctx;
12626 struct perf_event_context *dst_ctx;
12627 struct perf_event *event, *tmp;
12630 src_ctx = &per_cpu_ptr(pmu->pmu_cpu_context, src_cpu)->ctx;
12631 dst_ctx = &per_cpu_ptr(pmu->pmu_cpu_context, dst_cpu)->ctx;
12634 * See perf_event_ctx_lock() for comments on the details
12635 * of swizzling perf_event::ctx.
12637 mutex_lock_double(&src_ctx->mutex, &dst_ctx->mutex);
12638 list_for_each_entry_safe(event, tmp, &src_ctx->event_list,
12640 perf_remove_from_context(event, 0);
12641 unaccount_event_cpu(event, src_cpu);
12643 list_add(&event->migrate_entry, &events);
12647 * Wait for the events to quiesce before re-instating them.
12652 * Re-instate events in 2 passes.
12654 * Skip over group leaders and only install siblings on this first
12655 * pass, siblings will not get enabled without a leader, however a
12656 * leader will enable its siblings, even if those are still on the old
12659 list_for_each_entry_safe(event, tmp, &events, migrate_entry) {
12660 if (event->group_leader == event)
12663 list_del(&event->migrate_entry);
12664 if (event->state >= PERF_EVENT_STATE_OFF)
12665 event->state = PERF_EVENT_STATE_INACTIVE;
12666 account_event_cpu(event, dst_cpu);
12667 perf_install_in_context(dst_ctx, event, dst_cpu);
12672 * Once all the siblings are setup properly, install the group leaders
12675 list_for_each_entry_safe(event, tmp, &events, migrate_entry) {
12676 list_del(&event->migrate_entry);
12677 if (event->state >= PERF_EVENT_STATE_OFF)
12678 event->state = PERF_EVENT_STATE_INACTIVE;
12679 account_event_cpu(event, dst_cpu);
12680 perf_install_in_context(dst_ctx, event, dst_cpu);
12683 mutex_unlock(&dst_ctx->mutex);
12684 mutex_unlock(&src_ctx->mutex);
12686 EXPORT_SYMBOL_GPL(perf_pmu_migrate_context);
12688 static void sync_child_event(struct perf_event *child_event)
12690 struct perf_event *parent_event = child_event->parent;
12693 if (child_event->attr.inherit_stat) {
12694 struct task_struct *task = child_event->ctx->task;
12696 if (task && task != TASK_TOMBSTONE)
12697 perf_event_read_event(child_event, task);
12700 child_val = perf_event_count(child_event);
12703 * Add back the child's count to the parent's count:
12705 atomic64_add(child_val, &parent_event->child_count);
12706 atomic64_add(child_event->total_time_enabled,
12707 &parent_event->child_total_time_enabled);
12708 atomic64_add(child_event->total_time_running,
12709 &parent_event->child_total_time_running);
12713 perf_event_exit_event(struct perf_event *event, struct perf_event_context *ctx)
12715 struct perf_event *parent_event = event->parent;
12716 unsigned long detach_flags = 0;
12718 if (parent_event) {
12720 * Do not destroy the 'original' grouping; because of the
12721 * context switch optimization the original events could've
12722 * ended up in a random child task.
12724 * If we were to destroy the original group, all group related
12725 * operations would cease to function properly after this
12726 * random child dies.
12728 * Do destroy all inherited groups, we don't care about those
12729 * and being thorough is better.
12731 detach_flags = DETACH_GROUP | DETACH_CHILD;
12732 mutex_lock(&parent_event->child_mutex);
12735 perf_remove_from_context(event, detach_flags);
12737 raw_spin_lock_irq(&ctx->lock);
12738 if (event->state > PERF_EVENT_STATE_EXIT)
12739 perf_event_set_state(event, PERF_EVENT_STATE_EXIT);
12740 raw_spin_unlock_irq(&ctx->lock);
12743 * Child events can be freed.
12745 if (parent_event) {
12746 mutex_unlock(&parent_event->child_mutex);
12748 * Kick perf_poll() for is_event_hup();
12750 perf_event_wakeup(parent_event);
12752 put_event(parent_event);
12757 * Parent events are governed by their filedesc, retain them.
12759 perf_event_wakeup(event);
12762 static void perf_event_exit_task_context(struct task_struct *child, int ctxn)
12764 struct perf_event_context *child_ctx, *clone_ctx = NULL;
12765 struct perf_event *child_event, *next;
12767 WARN_ON_ONCE(child != current);
12769 child_ctx = perf_pin_task_context(child, ctxn);
12774 * In order to reduce the amount of tricky in ctx tear-down, we hold
12775 * ctx::mutex over the entire thing. This serializes against almost
12776 * everything that wants to access the ctx.
12778 * The exception is sys_perf_event_open() /
12779 * perf_event_create_kernel_count() which does find_get_context()
12780 * without ctx::mutex (it cannot because of the move_group double mutex
12781 * lock thing). See the comments in perf_install_in_context().
12783 mutex_lock(&child_ctx->mutex);
12786 * In a single ctx::lock section, de-schedule the events and detach the
12787 * context from the task such that we cannot ever get it scheduled back
12790 raw_spin_lock_irq(&child_ctx->lock);
12791 task_ctx_sched_out(__get_cpu_context(child_ctx), child_ctx, EVENT_ALL);
12794 * Now that the context is inactive, destroy the task <-> ctx relation
12795 * and mark the context dead.
12797 RCU_INIT_POINTER(child->perf_event_ctxp[ctxn], NULL);
12798 put_ctx(child_ctx); /* cannot be last */
12799 WRITE_ONCE(child_ctx->task, TASK_TOMBSTONE);
12800 put_task_struct(current); /* cannot be last */
12802 clone_ctx = unclone_ctx(child_ctx);
12803 raw_spin_unlock_irq(&child_ctx->lock);
12806 put_ctx(clone_ctx);
12809 * Report the task dead after unscheduling the events so that we
12810 * won't get any samples after PERF_RECORD_EXIT. We can however still
12811 * get a few PERF_RECORD_READ events.
12813 perf_event_task(child, child_ctx, 0);
12815 list_for_each_entry_safe(child_event, next, &child_ctx->event_list, event_entry)
12816 perf_event_exit_event(child_event, child_ctx);
12818 mutex_unlock(&child_ctx->mutex);
12820 put_ctx(child_ctx);
12824 * When a child task exits, feed back event values to parent events.
12826 * Can be called with exec_update_lock held when called from
12827 * setup_new_exec().
12829 void perf_event_exit_task(struct task_struct *child)
12831 struct perf_event *event, *tmp;
12834 mutex_lock(&child->perf_event_mutex);
12835 list_for_each_entry_safe(event, tmp, &child->perf_event_list,
12837 list_del_init(&event->owner_entry);
12840 * Ensure the list deletion is visible before we clear
12841 * the owner, closes a race against perf_release() where
12842 * we need to serialize on the owner->perf_event_mutex.
12844 smp_store_release(&event->owner, NULL);
12846 mutex_unlock(&child->perf_event_mutex);
12848 for_each_task_context_nr(ctxn)
12849 perf_event_exit_task_context(child, ctxn);
12852 * The perf_event_exit_task_context calls perf_event_task
12853 * with child's task_ctx, which generates EXIT events for
12854 * child contexts and sets child->perf_event_ctxp[] to NULL.
12855 * At this point we need to send EXIT events to cpu contexts.
12857 perf_event_task(child, NULL, 0);
12860 static void perf_free_event(struct perf_event *event,
12861 struct perf_event_context *ctx)
12863 struct perf_event *parent = event->parent;
12865 if (WARN_ON_ONCE(!parent))
12868 mutex_lock(&parent->child_mutex);
12869 list_del_init(&event->child_list);
12870 mutex_unlock(&parent->child_mutex);
12874 raw_spin_lock_irq(&ctx->lock);
12875 perf_group_detach(event);
12876 list_del_event(event, ctx);
12877 raw_spin_unlock_irq(&ctx->lock);
12882 * Free a context as created by inheritance by perf_event_init_task() below,
12883 * used by fork() in case of fail.
12885 * Even though the task has never lived, the context and events have been
12886 * exposed through the child_list, so we must take care tearing it all down.
12888 void perf_event_free_task(struct task_struct *task)
12890 struct perf_event_context *ctx;
12891 struct perf_event *event, *tmp;
12894 for_each_task_context_nr(ctxn) {
12895 ctx = task->perf_event_ctxp[ctxn];
12899 mutex_lock(&ctx->mutex);
12900 raw_spin_lock_irq(&ctx->lock);
12902 * Destroy the task <-> ctx relation and mark the context dead.
12904 * This is important because even though the task hasn't been
12905 * exposed yet the context has been (through child_list).
12907 RCU_INIT_POINTER(task->perf_event_ctxp[ctxn], NULL);
12908 WRITE_ONCE(ctx->task, TASK_TOMBSTONE);
12909 put_task_struct(task); /* cannot be last */
12910 raw_spin_unlock_irq(&ctx->lock);
12912 list_for_each_entry_safe(event, tmp, &ctx->event_list, event_entry)
12913 perf_free_event(event, ctx);
12915 mutex_unlock(&ctx->mutex);
12918 * perf_event_release_kernel() could've stolen some of our
12919 * child events and still have them on its free_list. In that
12920 * case we must wait for these events to have been freed (in
12921 * particular all their references to this task must've been
12924 * Without this copy_process() will unconditionally free this
12925 * task (irrespective of its reference count) and
12926 * _free_event()'s put_task_struct(event->hw.target) will be a
12929 * Wait for all events to drop their context reference.
12931 wait_var_event(&ctx->refcount, refcount_read(&ctx->refcount) == 1);
12932 put_ctx(ctx); /* must be last */
12936 void perf_event_delayed_put(struct task_struct *task)
12940 for_each_task_context_nr(ctxn)
12941 WARN_ON_ONCE(task->perf_event_ctxp[ctxn]);
12944 struct file *perf_event_get(unsigned int fd)
12946 struct file *file = fget(fd);
12948 return ERR_PTR(-EBADF);
12950 if (file->f_op != &perf_fops) {
12952 return ERR_PTR(-EBADF);
12958 const struct perf_event *perf_get_event(struct file *file)
12960 if (file->f_op != &perf_fops)
12961 return ERR_PTR(-EINVAL);
12963 return file->private_data;
12966 const struct perf_event_attr *perf_event_attrs(struct perf_event *event)
12969 return ERR_PTR(-EINVAL);
12971 return &event->attr;
12975 * Inherit an event from parent task to child task.
12978 * - valid pointer on success
12979 * - NULL for orphaned events
12980 * - IS_ERR() on error
12982 static struct perf_event *
12983 inherit_event(struct perf_event *parent_event,
12984 struct task_struct *parent,
12985 struct perf_event_context *parent_ctx,
12986 struct task_struct *child,
12987 struct perf_event *group_leader,
12988 struct perf_event_context *child_ctx)
12990 enum perf_event_state parent_state = parent_event->state;
12991 struct perf_event *child_event;
12992 unsigned long flags;
12995 * Instead of creating recursive hierarchies of events,
12996 * we link inherited events back to the original parent,
12997 * which has a filp for sure, which we use as the reference
13000 if (parent_event->parent)
13001 parent_event = parent_event->parent;
13003 child_event = perf_event_alloc(&parent_event->attr,
13006 group_leader, parent_event,
13008 if (IS_ERR(child_event))
13009 return child_event;
13012 if ((child_event->attach_state & PERF_ATTACH_TASK_DATA) &&
13013 !child_ctx->task_ctx_data) {
13014 struct pmu *pmu = child_event->pmu;
13016 child_ctx->task_ctx_data = alloc_task_ctx_data(pmu);
13017 if (!child_ctx->task_ctx_data) {
13018 free_event(child_event);
13019 return ERR_PTR(-ENOMEM);
13024 * is_orphaned_event() and list_add_tail(&parent_event->child_list)
13025 * must be under the same lock in order to serialize against
13026 * perf_event_release_kernel(), such that either we must observe
13027 * is_orphaned_event() or they will observe us on the child_list.
13029 mutex_lock(&parent_event->child_mutex);
13030 if (is_orphaned_event(parent_event) ||
13031 !atomic_long_inc_not_zero(&parent_event->refcount)) {
13032 mutex_unlock(&parent_event->child_mutex);
13033 /* task_ctx_data is freed with child_ctx */
13034 free_event(child_event);
13038 get_ctx(child_ctx);
13041 * Make the child state follow the state of the parent event,
13042 * not its attr.disabled bit. We hold the parent's mutex,
13043 * so we won't race with perf_event_{en, dis}able_family.
13045 if (parent_state >= PERF_EVENT_STATE_INACTIVE)
13046 child_event->state = PERF_EVENT_STATE_INACTIVE;
13048 child_event->state = PERF_EVENT_STATE_OFF;
13050 if (parent_event->attr.freq) {
13051 u64 sample_period = parent_event->hw.sample_period;
13052 struct hw_perf_event *hwc = &child_event->hw;
13054 hwc->sample_period = sample_period;
13055 hwc->last_period = sample_period;
13057 local64_set(&hwc->period_left, sample_period);
13060 child_event->ctx = child_ctx;
13061 child_event->overflow_handler = parent_event->overflow_handler;
13062 child_event->overflow_handler_context
13063 = parent_event->overflow_handler_context;
13066 * Precalculate sample_data sizes
13068 perf_event__header_size(child_event);
13069 perf_event__id_header_size(child_event);
13072 * Link it up in the child's context:
13074 raw_spin_lock_irqsave(&child_ctx->lock, flags);
13075 add_event_to_ctx(child_event, child_ctx);
13076 child_event->attach_state |= PERF_ATTACH_CHILD;
13077 raw_spin_unlock_irqrestore(&child_ctx->lock, flags);
13080 * Link this into the parent event's child list
13082 list_add_tail(&child_event->child_list, &parent_event->child_list);
13083 mutex_unlock(&parent_event->child_mutex);
13085 return child_event;
13089 * Inherits an event group.
13091 * This will quietly suppress orphaned events; !inherit_event() is not an error.
13092 * This matches with perf_event_release_kernel() removing all child events.
13098 static int inherit_group(struct perf_event *parent_event,
13099 struct task_struct *parent,
13100 struct perf_event_context *parent_ctx,
13101 struct task_struct *child,
13102 struct perf_event_context *child_ctx)
13104 struct perf_event *leader;
13105 struct perf_event *sub;
13106 struct perf_event *child_ctr;
13108 leader = inherit_event(parent_event, parent, parent_ctx,
13109 child, NULL, child_ctx);
13110 if (IS_ERR(leader))
13111 return PTR_ERR(leader);
13113 * @leader can be NULL here because of is_orphaned_event(). In this
13114 * case inherit_event() will create individual events, similar to what
13115 * perf_group_detach() would do anyway.
13117 for_each_sibling_event(sub, parent_event) {
13118 child_ctr = inherit_event(sub, parent, parent_ctx,
13119 child, leader, child_ctx);
13120 if (IS_ERR(child_ctr))
13121 return PTR_ERR(child_ctr);
13123 if (sub->aux_event == parent_event && child_ctr &&
13124 !perf_get_aux_event(child_ctr, leader))
13131 * Creates the child task context and tries to inherit the event-group.
13133 * Clears @inherited_all on !attr.inherited or error. Note that we'll leave
13134 * inherited_all set when we 'fail' to inherit an orphaned event; this is
13135 * consistent with perf_event_release_kernel() removing all child events.
13142 inherit_task_group(struct perf_event *event, struct task_struct *parent,
13143 struct perf_event_context *parent_ctx,
13144 struct task_struct *child, int ctxn,
13145 u64 clone_flags, int *inherited_all)
13148 struct perf_event_context *child_ctx;
13150 if (!event->attr.inherit ||
13151 (event->attr.inherit_thread && !(clone_flags & CLONE_THREAD)) ||
13152 /* Do not inherit if sigtrap and signal handlers were cleared. */
13153 (event->attr.sigtrap && (clone_flags & CLONE_CLEAR_SIGHAND))) {
13154 *inherited_all = 0;
13158 child_ctx = child->perf_event_ctxp[ctxn];
13161 * This is executed from the parent task context, so
13162 * inherit events that have been marked for cloning.
13163 * First allocate and initialize a context for the
13166 child_ctx = alloc_perf_context(parent_ctx->pmu, child);
13170 child->perf_event_ctxp[ctxn] = child_ctx;
13173 ret = inherit_group(event, parent, parent_ctx,
13177 *inherited_all = 0;
13183 * Initialize the perf_event context in task_struct
13185 static int perf_event_init_context(struct task_struct *child, int ctxn,
13188 struct perf_event_context *child_ctx, *parent_ctx;
13189 struct perf_event_context *cloned_ctx;
13190 struct perf_event *event;
13191 struct task_struct *parent = current;
13192 int inherited_all = 1;
13193 unsigned long flags;
13196 if (likely(!parent->perf_event_ctxp[ctxn]))
13200 * If the parent's context is a clone, pin it so it won't get
13201 * swapped under us.
13203 parent_ctx = perf_pin_task_context(parent, ctxn);
13208 * No need to check if parent_ctx != NULL here; since we saw
13209 * it non-NULL earlier, the only reason for it to become NULL
13210 * is if we exit, and since we're currently in the middle of
13211 * a fork we can't be exiting at the same time.
13215 * Lock the parent list. No need to lock the child - not PID
13216 * hashed yet and not running, so nobody can access it.
13218 mutex_lock(&parent_ctx->mutex);
13221 * We dont have to disable NMIs - we are only looking at
13222 * the list, not manipulating it:
13224 perf_event_groups_for_each(event, &parent_ctx->pinned_groups) {
13225 ret = inherit_task_group(event, parent, parent_ctx,
13226 child, ctxn, clone_flags,
13233 * We can't hold ctx->lock when iterating the ->flexible_group list due
13234 * to allocations, but we need to prevent rotation because
13235 * rotate_ctx() will change the list from interrupt context.
13237 raw_spin_lock_irqsave(&parent_ctx->lock, flags);
13238 parent_ctx->rotate_disable = 1;
13239 raw_spin_unlock_irqrestore(&parent_ctx->lock, flags);
13241 perf_event_groups_for_each(event, &parent_ctx->flexible_groups) {
13242 ret = inherit_task_group(event, parent, parent_ctx,
13243 child, ctxn, clone_flags,
13249 raw_spin_lock_irqsave(&parent_ctx->lock, flags);
13250 parent_ctx->rotate_disable = 0;
13252 child_ctx = child->perf_event_ctxp[ctxn];
13254 if (child_ctx && inherited_all) {
13256 * Mark the child context as a clone of the parent
13257 * context, or of whatever the parent is a clone of.
13259 * Note that if the parent is a clone, the holding of
13260 * parent_ctx->lock avoids it from being uncloned.
13262 cloned_ctx = parent_ctx->parent_ctx;
13264 child_ctx->parent_ctx = cloned_ctx;
13265 child_ctx->parent_gen = parent_ctx->parent_gen;
13267 child_ctx->parent_ctx = parent_ctx;
13268 child_ctx->parent_gen = parent_ctx->generation;
13270 get_ctx(child_ctx->parent_ctx);
13273 raw_spin_unlock_irqrestore(&parent_ctx->lock, flags);
13275 mutex_unlock(&parent_ctx->mutex);
13277 perf_unpin_context(parent_ctx);
13278 put_ctx(parent_ctx);
13284 * Initialize the perf_event context in task_struct
13286 int perf_event_init_task(struct task_struct *child, u64 clone_flags)
13290 memset(child->perf_event_ctxp, 0, sizeof(child->perf_event_ctxp));
13291 mutex_init(&child->perf_event_mutex);
13292 INIT_LIST_HEAD(&child->perf_event_list);
13294 for_each_task_context_nr(ctxn) {
13295 ret = perf_event_init_context(child, ctxn, clone_flags);
13297 perf_event_free_task(child);
13305 static void __init perf_event_init_all_cpus(void)
13307 struct swevent_htable *swhash;
13310 zalloc_cpumask_var(&perf_online_mask, GFP_KERNEL);
13312 for_each_possible_cpu(cpu) {
13313 swhash = &per_cpu(swevent_htable, cpu);
13314 mutex_init(&swhash->hlist_mutex);
13315 INIT_LIST_HEAD(&per_cpu(active_ctx_list, cpu));
13317 INIT_LIST_HEAD(&per_cpu(pmu_sb_events.list, cpu));
13318 raw_spin_lock_init(&per_cpu(pmu_sb_events.lock, cpu));
13320 #ifdef CONFIG_CGROUP_PERF
13321 INIT_LIST_HEAD(&per_cpu(cgrp_cpuctx_list, cpu));
13323 INIT_LIST_HEAD(&per_cpu(sched_cb_list, cpu));
13327 static void perf_swevent_init_cpu(unsigned int cpu)
13329 struct swevent_htable *swhash = &per_cpu(swevent_htable, cpu);
13331 mutex_lock(&swhash->hlist_mutex);
13332 if (swhash->hlist_refcount > 0 && !swevent_hlist_deref(swhash)) {
13333 struct swevent_hlist *hlist;
13335 hlist = kzalloc_node(sizeof(*hlist), GFP_KERNEL, cpu_to_node(cpu));
13337 rcu_assign_pointer(swhash->swevent_hlist, hlist);
13339 mutex_unlock(&swhash->hlist_mutex);
13342 #if defined CONFIG_HOTPLUG_CPU || defined CONFIG_KEXEC_CORE
13343 static void __perf_event_exit_context(void *__info)
13345 struct perf_event_context *ctx = __info;
13346 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
13347 struct perf_event *event;
13349 raw_spin_lock(&ctx->lock);
13350 ctx_sched_out(ctx, cpuctx, EVENT_TIME);
13351 list_for_each_entry(event, &ctx->event_list, event_entry)
13352 __perf_remove_from_context(event, cpuctx, ctx, (void *)DETACH_GROUP);
13353 raw_spin_unlock(&ctx->lock);
13356 static void perf_event_exit_cpu_context(int cpu)
13358 struct perf_cpu_context *cpuctx;
13359 struct perf_event_context *ctx;
13362 mutex_lock(&pmus_lock);
13363 list_for_each_entry(pmu, &pmus, entry) {
13364 cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
13365 ctx = &cpuctx->ctx;
13367 mutex_lock(&ctx->mutex);
13368 smp_call_function_single(cpu, __perf_event_exit_context, ctx, 1);
13369 cpuctx->online = 0;
13370 mutex_unlock(&ctx->mutex);
13372 cpumask_clear_cpu(cpu, perf_online_mask);
13373 mutex_unlock(&pmus_lock);
13377 static void perf_event_exit_cpu_context(int cpu) { }
13381 int perf_event_init_cpu(unsigned int cpu)
13383 struct perf_cpu_context *cpuctx;
13384 struct perf_event_context *ctx;
13387 perf_swevent_init_cpu(cpu);
13389 mutex_lock(&pmus_lock);
13390 cpumask_set_cpu(cpu, perf_online_mask);
13391 list_for_each_entry(pmu, &pmus, entry) {
13392 cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
13393 ctx = &cpuctx->ctx;
13395 mutex_lock(&ctx->mutex);
13396 cpuctx->online = 1;
13397 mutex_unlock(&ctx->mutex);
13399 mutex_unlock(&pmus_lock);
13404 int perf_event_exit_cpu(unsigned int cpu)
13406 perf_event_exit_cpu_context(cpu);
13411 perf_reboot(struct notifier_block *notifier, unsigned long val, void *v)
13415 for_each_online_cpu(cpu)
13416 perf_event_exit_cpu(cpu);
13422 * Run the perf reboot notifier at the very last possible moment so that
13423 * the generic watchdog code runs as long as possible.
13425 static struct notifier_block perf_reboot_notifier = {
13426 .notifier_call = perf_reboot,
13427 .priority = INT_MIN,
13430 void __init perf_event_init(void)
13434 idr_init(&pmu_idr);
13436 perf_event_init_all_cpus();
13437 init_srcu_struct(&pmus_srcu);
13438 perf_pmu_register(&perf_swevent, "software", PERF_TYPE_SOFTWARE);
13439 perf_pmu_register(&perf_cpu_clock, NULL, -1);
13440 perf_pmu_register(&perf_task_clock, NULL, -1);
13441 perf_tp_register();
13442 perf_event_init_cpu(smp_processor_id());
13443 register_reboot_notifier(&perf_reboot_notifier);
13445 ret = init_hw_breakpoint();
13446 WARN(ret, "hw_breakpoint initialization failed with: %d", ret);
13448 perf_event_cache = KMEM_CACHE(perf_event, SLAB_PANIC);
13451 * Build time assertion that we keep the data_head at the intended
13452 * location. IOW, validation we got the __reserved[] size right.
13454 BUILD_BUG_ON((offsetof(struct perf_event_mmap_page, data_head))
13458 ssize_t perf_event_sysfs_show(struct device *dev, struct device_attribute *attr,
13461 struct perf_pmu_events_attr *pmu_attr =
13462 container_of(attr, struct perf_pmu_events_attr, attr);
13464 if (pmu_attr->event_str)
13465 return sprintf(page, "%s\n", pmu_attr->event_str);
13469 EXPORT_SYMBOL_GPL(perf_event_sysfs_show);
13471 static int __init perf_event_sysfs_init(void)
13476 mutex_lock(&pmus_lock);
13478 ret = bus_register(&pmu_bus);
13482 list_for_each_entry(pmu, &pmus, entry) {
13483 if (!pmu->name || pmu->type < 0)
13486 ret = pmu_dev_alloc(pmu);
13487 WARN(ret, "Failed to register pmu: %s, reason %d\n", pmu->name, ret);
13489 pmu_bus_running = 1;
13493 mutex_unlock(&pmus_lock);
13497 device_initcall(perf_event_sysfs_init);
13499 #ifdef CONFIG_CGROUP_PERF
13500 static struct cgroup_subsys_state *
13501 perf_cgroup_css_alloc(struct cgroup_subsys_state *parent_css)
13503 struct perf_cgroup *jc;
13505 jc = kzalloc(sizeof(*jc), GFP_KERNEL);
13507 return ERR_PTR(-ENOMEM);
13509 jc->info = alloc_percpu(struct perf_cgroup_info);
13512 return ERR_PTR(-ENOMEM);
13518 static void perf_cgroup_css_free(struct cgroup_subsys_state *css)
13520 struct perf_cgroup *jc = container_of(css, struct perf_cgroup, css);
13522 free_percpu(jc->info);
13526 static int perf_cgroup_css_online(struct cgroup_subsys_state *css)
13528 perf_event_cgroup(css->cgroup);
13532 static int __perf_cgroup_move(void *info)
13534 struct task_struct *task = info;
13536 perf_cgroup_switch(task, PERF_CGROUP_SWOUT | PERF_CGROUP_SWIN);
13541 static void perf_cgroup_attach(struct cgroup_taskset *tset)
13543 struct task_struct *task;
13544 struct cgroup_subsys_state *css;
13546 cgroup_taskset_for_each(task, css, tset)
13547 task_function_call(task, __perf_cgroup_move, task);
13550 struct cgroup_subsys perf_event_cgrp_subsys = {
13551 .css_alloc = perf_cgroup_css_alloc,
13552 .css_free = perf_cgroup_css_free,
13553 .css_online = perf_cgroup_css_online,
13554 .attach = perf_cgroup_attach,
13556 * Implicitly enable on dfl hierarchy so that perf events can
13557 * always be filtered by cgroup2 path as long as perf_event
13558 * controller is not mounted on a legacy hierarchy.
13560 .implicit_on_dfl = true,
13563 #endif /* CONFIG_CGROUP_PERF */
13565 DEFINE_STATIC_CALL_RET0(perf_snapshot_branch_stack, perf_snapshot_branch_stack_t);