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, *tmp;
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_safe(cpuctx, tmp, 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);
2466 * Cgroup events are per-cpu events, and must IPI because of
2469 if (!ctx->is_active && !is_cgroup_event(event)) {
2470 __perf_remove_from_context(event, __get_cpu_context(ctx),
2471 ctx, (void *)flags);
2472 raw_spin_unlock_irq(&ctx->lock);
2475 raw_spin_unlock_irq(&ctx->lock);
2477 event_function_call(event, __perf_remove_from_context, (void *)flags);
2481 * Cross CPU call to disable a performance event
2483 static void __perf_event_disable(struct perf_event *event,
2484 struct perf_cpu_context *cpuctx,
2485 struct perf_event_context *ctx,
2488 if (event->state < PERF_EVENT_STATE_INACTIVE)
2491 if (ctx->is_active & EVENT_TIME) {
2492 update_context_time(ctx);
2493 update_cgrp_time_from_event(event);
2496 if (event == event->group_leader)
2497 group_sched_out(event, cpuctx, ctx);
2499 event_sched_out(event, cpuctx, ctx);
2501 perf_event_set_state(event, PERF_EVENT_STATE_OFF);
2502 perf_cgroup_event_disable(event, ctx);
2508 * If event->ctx is a cloned context, callers must make sure that
2509 * every task struct that event->ctx->task could possibly point to
2510 * remains valid. This condition is satisfied when called through
2511 * perf_event_for_each_child or perf_event_for_each because they
2512 * hold the top-level event's child_mutex, so any descendant that
2513 * goes to exit will block in perf_event_exit_event().
2515 * When called from perf_pending_event it's OK because event->ctx
2516 * is the current context on this CPU and preemption is disabled,
2517 * hence we can't get into perf_event_task_sched_out for this context.
2519 static void _perf_event_disable(struct perf_event *event)
2521 struct perf_event_context *ctx = event->ctx;
2523 raw_spin_lock_irq(&ctx->lock);
2524 if (event->state <= PERF_EVENT_STATE_OFF) {
2525 raw_spin_unlock_irq(&ctx->lock);
2528 raw_spin_unlock_irq(&ctx->lock);
2530 event_function_call(event, __perf_event_disable, NULL);
2533 void perf_event_disable_local(struct perf_event *event)
2535 event_function_local(event, __perf_event_disable, NULL);
2539 * Strictly speaking kernel users cannot create groups and therefore this
2540 * interface does not need the perf_event_ctx_lock() magic.
2542 void perf_event_disable(struct perf_event *event)
2544 struct perf_event_context *ctx;
2546 ctx = perf_event_ctx_lock(event);
2547 _perf_event_disable(event);
2548 perf_event_ctx_unlock(event, ctx);
2550 EXPORT_SYMBOL_GPL(perf_event_disable);
2552 void perf_event_disable_inatomic(struct perf_event *event)
2554 WRITE_ONCE(event->pending_disable, smp_processor_id());
2555 /* can fail, see perf_pending_event_disable() */
2556 irq_work_queue(&event->pending);
2559 #define MAX_INTERRUPTS (~0ULL)
2561 static void perf_log_throttle(struct perf_event *event, int enable);
2562 static void perf_log_itrace_start(struct perf_event *event);
2565 event_sched_in(struct perf_event *event,
2566 struct perf_cpu_context *cpuctx,
2567 struct perf_event_context *ctx)
2571 WARN_ON_ONCE(event->ctx != ctx);
2573 lockdep_assert_held(&ctx->lock);
2575 if (event->state <= PERF_EVENT_STATE_OFF)
2578 WRITE_ONCE(event->oncpu, smp_processor_id());
2580 * Order event::oncpu write to happen before the ACTIVE state is
2581 * visible. This allows perf_event_{stop,read}() to observe the correct
2582 * ->oncpu if it sees ACTIVE.
2585 perf_event_set_state(event, PERF_EVENT_STATE_ACTIVE);
2588 * Unthrottle events, since we scheduled we might have missed several
2589 * ticks already, also for a heavily scheduling task there is little
2590 * guarantee it'll get a tick in a timely manner.
2592 if (unlikely(event->hw.interrupts == MAX_INTERRUPTS)) {
2593 perf_log_throttle(event, 1);
2594 event->hw.interrupts = 0;
2597 perf_pmu_disable(event->pmu);
2599 perf_log_itrace_start(event);
2601 if (event->pmu->add(event, PERF_EF_START)) {
2602 perf_event_set_state(event, PERF_EVENT_STATE_INACTIVE);
2608 if (!is_software_event(event))
2609 cpuctx->active_oncpu++;
2610 if (!ctx->nr_active++)
2611 perf_event_ctx_activate(ctx);
2612 if (event->attr.freq && event->attr.sample_freq)
2615 if (event->attr.exclusive)
2616 cpuctx->exclusive = 1;
2619 perf_pmu_enable(event->pmu);
2625 group_sched_in(struct perf_event *group_event,
2626 struct perf_cpu_context *cpuctx,
2627 struct perf_event_context *ctx)
2629 struct perf_event *event, *partial_group = NULL;
2630 struct pmu *pmu = ctx->pmu;
2632 if (group_event->state == PERF_EVENT_STATE_OFF)
2635 pmu->start_txn(pmu, PERF_PMU_TXN_ADD);
2637 if (event_sched_in(group_event, cpuctx, ctx))
2641 * Schedule in siblings as one group (if any):
2643 for_each_sibling_event(event, group_event) {
2644 if (event_sched_in(event, cpuctx, ctx)) {
2645 partial_group = event;
2650 if (!pmu->commit_txn(pmu))
2655 * Groups can be scheduled in as one unit only, so undo any
2656 * partial group before returning:
2657 * The events up to the failed event are scheduled out normally.
2659 for_each_sibling_event(event, group_event) {
2660 if (event == partial_group)
2663 event_sched_out(event, cpuctx, ctx);
2665 event_sched_out(group_event, cpuctx, ctx);
2668 pmu->cancel_txn(pmu);
2673 * Work out whether we can put this event group on the CPU now.
2675 static int group_can_go_on(struct perf_event *event,
2676 struct perf_cpu_context *cpuctx,
2680 * Groups consisting entirely of software events can always go on.
2682 if (event->group_caps & PERF_EV_CAP_SOFTWARE)
2685 * If an exclusive group is already on, no other hardware
2688 if (cpuctx->exclusive)
2691 * If this group is exclusive and there are already
2692 * events on the CPU, it can't go on.
2694 if (event->attr.exclusive && !list_empty(get_event_list(event)))
2697 * Otherwise, try to add it if all previous groups were able
2703 static void add_event_to_ctx(struct perf_event *event,
2704 struct perf_event_context *ctx)
2706 list_add_event(event, ctx);
2707 perf_group_attach(event);
2710 static void ctx_sched_out(struct perf_event_context *ctx,
2711 struct perf_cpu_context *cpuctx,
2712 enum event_type_t event_type);
2714 ctx_sched_in(struct perf_event_context *ctx,
2715 struct perf_cpu_context *cpuctx,
2716 enum event_type_t event_type,
2717 struct task_struct *task);
2719 static void task_ctx_sched_out(struct perf_cpu_context *cpuctx,
2720 struct perf_event_context *ctx,
2721 enum event_type_t event_type)
2723 if (!cpuctx->task_ctx)
2726 if (WARN_ON_ONCE(ctx != cpuctx->task_ctx))
2729 ctx_sched_out(ctx, cpuctx, event_type);
2732 static void perf_event_sched_in(struct perf_cpu_context *cpuctx,
2733 struct perf_event_context *ctx,
2734 struct task_struct *task)
2736 cpu_ctx_sched_in(cpuctx, EVENT_PINNED, task);
2738 ctx_sched_in(ctx, cpuctx, EVENT_PINNED, task);
2739 cpu_ctx_sched_in(cpuctx, EVENT_FLEXIBLE, task);
2741 ctx_sched_in(ctx, cpuctx, EVENT_FLEXIBLE, task);
2745 * We want to maintain the following priority of scheduling:
2746 * - CPU pinned (EVENT_CPU | EVENT_PINNED)
2747 * - task pinned (EVENT_PINNED)
2748 * - CPU flexible (EVENT_CPU | EVENT_FLEXIBLE)
2749 * - task flexible (EVENT_FLEXIBLE).
2751 * In order to avoid unscheduling and scheduling back in everything every
2752 * time an event is added, only do it for the groups of equal priority and
2755 * This can be called after a batch operation on task events, in which case
2756 * event_type is a bit mask of the types of events involved. For CPU events,
2757 * event_type is only either EVENT_PINNED or EVENT_FLEXIBLE.
2759 static void ctx_resched(struct perf_cpu_context *cpuctx,
2760 struct perf_event_context *task_ctx,
2761 enum event_type_t event_type)
2763 enum event_type_t ctx_event_type;
2764 bool cpu_event = !!(event_type & EVENT_CPU);
2767 * If pinned groups are involved, flexible groups also need to be
2770 if (event_type & EVENT_PINNED)
2771 event_type |= EVENT_FLEXIBLE;
2773 ctx_event_type = event_type & EVENT_ALL;
2775 perf_pmu_disable(cpuctx->ctx.pmu);
2777 task_ctx_sched_out(cpuctx, task_ctx, event_type);
2780 * Decide which cpu ctx groups to schedule out based on the types
2781 * of events that caused rescheduling:
2782 * - EVENT_CPU: schedule out corresponding groups;
2783 * - EVENT_PINNED task events: schedule out EVENT_FLEXIBLE groups;
2784 * - otherwise, do nothing more.
2787 cpu_ctx_sched_out(cpuctx, ctx_event_type);
2788 else if (ctx_event_type & EVENT_PINNED)
2789 cpu_ctx_sched_out(cpuctx, EVENT_FLEXIBLE);
2791 perf_event_sched_in(cpuctx, task_ctx, current);
2792 perf_pmu_enable(cpuctx->ctx.pmu);
2795 void perf_pmu_resched(struct pmu *pmu)
2797 struct perf_cpu_context *cpuctx = this_cpu_ptr(pmu->pmu_cpu_context);
2798 struct perf_event_context *task_ctx = cpuctx->task_ctx;
2800 perf_ctx_lock(cpuctx, task_ctx);
2801 ctx_resched(cpuctx, task_ctx, EVENT_ALL|EVENT_CPU);
2802 perf_ctx_unlock(cpuctx, task_ctx);
2806 * Cross CPU call to install and enable a performance event
2808 * Very similar to remote_function() + event_function() but cannot assume that
2809 * things like ctx->is_active and cpuctx->task_ctx are set.
2811 static int __perf_install_in_context(void *info)
2813 struct perf_event *event = info;
2814 struct perf_event_context *ctx = event->ctx;
2815 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
2816 struct perf_event_context *task_ctx = cpuctx->task_ctx;
2817 bool reprogram = true;
2820 raw_spin_lock(&cpuctx->ctx.lock);
2822 raw_spin_lock(&ctx->lock);
2825 reprogram = (ctx->task == current);
2828 * If the task is running, it must be running on this CPU,
2829 * otherwise we cannot reprogram things.
2831 * If its not running, we don't care, ctx->lock will
2832 * serialize against it becoming runnable.
2834 if (task_curr(ctx->task) && !reprogram) {
2839 WARN_ON_ONCE(reprogram && cpuctx->task_ctx && cpuctx->task_ctx != ctx);
2840 } else if (task_ctx) {
2841 raw_spin_lock(&task_ctx->lock);
2844 #ifdef CONFIG_CGROUP_PERF
2845 if (event->state > PERF_EVENT_STATE_OFF && is_cgroup_event(event)) {
2847 * If the current cgroup doesn't match the event's
2848 * cgroup, we should not try to schedule it.
2850 struct perf_cgroup *cgrp = perf_cgroup_from_task(current, ctx);
2851 reprogram = cgroup_is_descendant(cgrp->css.cgroup,
2852 event->cgrp->css.cgroup);
2857 ctx_sched_out(ctx, cpuctx, EVENT_TIME);
2858 add_event_to_ctx(event, ctx);
2859 ctx_resched(cpuctx, task_ctx, get_event_type(event));
2861 add_event_to_ctx(event, ctx);
2865 perf_ctx_unlock(cpuctx, task_ctx);
2870 static bool exclusive_event_installable(struct perf_event *event,
2871 struct perf_event_context *ctx);
2874 * Attach a performance event to a context.
2876 * Very similar to event_function_call, see comment there.
2879 perf_install_in_context(struct perf_event_context *ctx,
2880 struct perf_event *event,
2883 struct task_struct *task = READ_ONCE(ctx->task);
2885 lockdep_assert_held(&ctx->mutex);
2887 WARN_ON_ONCE(!exclusive_event_installable(event, ctx));
2889 if (event->cpu != -1)
2893 * Ensures that if we can observe event->ctx, both the event and ctx
2894 * will be 'complete'. See perf_iterate_sb_cpu().
2896 smp_store_release(&event->ctx, ctx);
2899 * perf_event_attr::disabled events will not run and can be initialized
2900 * without IPI. Except when this is the first event for the context, in
2901 * that case we need the magic of the IPI to set ctx->is_active.
2902 * Similarly, cgroup events for the context also needs the IPI to
2903 * manipulate the cgrp_cpuctx_list.
2905 * The IOC_ENABLE that is sure to follow the creation of a disabled
2906 * event will issue the IPI and reprogram the hardware.
2908 if (__perf_effective_state(event) == PERF_EVENT_STATE_OFF &&
2909 ctx->nr_events && !is_cgroup_event(event)) {
2910 raw_spin_lock_irq(&ctx->lock);
2911 if (ctx->task == TASK_TOMBSTONE) {
2912 raw_spin_unlock_irq(&ctx->lock);
2915 add_event_to_ctx(event, ctx);
2916 raw_spin_unlock_irq(&ctx->lock);
2921 cpu_function_call(cpu, __perf_install_in_context, event);
2926 * Should not happen, we validate the ctx is still alive before calling.
2928 if (WARN_ON_ONCE(task == TASK_TOMBSTONE))
2932 * Installing events is tricky because we cannot rely on ctx->is_active
2933 * to be set in case this is the nr_events 0 -> 1 transition.
2935 * Instead we use task_curr(), which tells us if the task is running.
2936 * However, since we use task_curr() outside of rq::lock, we can race
2937 * against the actual state. This means the result can be wrong.
2939 * If we get a false positive, we retry, this is harmless.
2941 * If we get a false negative, things are complicated. If we are after
2942 * perf_event_context_sched_in() ctx::lock will serialize us, and the
2943 * value must be correct. If we're before, it doesn't matter since
2944 * perf_event_context_sched_in() will program the counter.
2946 * However, this hinges on the remote context switch having observed
2947 * our task->perf_event_ctxp[] store, such that it will in fact take
2948 * ctx::lock in perf_event_context_sched_in().
2950 * We do this by task_function_call(), if the IPI fails to hit the task
2951 * we know any future context switch of task must see the
2952 * perf_event_ctpx[] store.
2956 * This smp_mb() orders the task->perf_event_ctxp[] store with the
2957 * task_cpu() load, such that if the IPI then does not find the task
2958 * running, a future context switch of that task must observe the
2963 if (!task_function_call(task, __perf_install_in_context, event))
2966 raw_spin_lock_irq(&ctx->lock);
2968 if (WARN_ON_ONCE(task == TASK_TOMBSTONE)) {
2970 * Cannot happen because we already checked above (which also
2971 * cannot happen), and we hold ctx->mutex, which serializes us
2972 * against perf_event_exit_task_context().
2974 raw_spin_unlock_irq(&ctx->lock);
2978 * If the task is not running, ctx->lock will avoid it becoming so,
2979 * thus we can safely install the event.
2981 if (task_curr(task)) {
2982 raw_spin_unlock_irq(&ctx->lock);
2985 add_event_to_ctx(event, ctx);
2986 raw_spin_unlock_irq(&ctx->lock);
2990 * Cross CPU call to enable a performance event
2992 static void __perf_event_enable(struct perf_event *event,
2993 struct perf_cpu_context *cpuctx,
2994 struct perf_event_context *ctx,
2997 struct perf_event *leader = event->group_leader;
2998 struct perf_event_context *task_ctx;
3000 if (event->state >= PERF_EVENT_STATE_INACTIVE ||
3001 event->state <= PERF_EVENT_STATE_ERROR)
3005 ctx_sched_out(ctx, cpuctx, EVENT_TIME);
3007 perf_event_set_state(event, PERF_EVENT_STATE_INACTIVE);
3008 perf_cgroup_event_enable(event, ctx);
3010 if (!ctx->is_active)
3013 if (!event_filter_match(event)) {
3014 ctx_sched_in(ctx, cpuctx, EVENT_TIME, current);
3019 * If the event is in a group and isn't the group leader,
3020 * then don't put it on unless the group is on.
3022 if (leader != event && leader->state != PERF_EVENT_STATE_ACTIVE) {
3023 ctx_sched_in(ctx, cpuctx, EVENT_TIME, current);
3027 task_ctx = cpuctx->task_ctx;
3029 WARN_ON_ONCE(task_ctx != ctx);
3031 ctx_resched(cpuctx, task_ctx, get_event_type(event));
3037 * If event->ctx is a cloned context, callers must make sure that
3038 * every task struct that event->ctx->task could possibly point to
3039 * remains valid. This condition is satisfied when called through
3040 * perf_event_for_each_child or perf_event_for_each as described
3041 * for perf_event_disable.
3043 static void _perf_event_enable(struct perf_event *event)
3045 struct perf_event_context *ctx = event->ctx;
3047 raw_spin_lock_irq(&ctx->lock);
3048 if (event->state >= PERF_EVENT_STATE_INACTIVE ||
3049 event->state < PERF_EVENT_STATE_ERROR) {
3051 raw_spin_unlock_irq(&ctx->lock);
3056 * If the event is in error state, clear that first.
3058 * That way, if we see the event in error state below, we know that it
3059 * has gone back into error state, as distinct from the task having
3060 * been scheduled away before the cross-call arrived.
3062 if (event->state == PERF_EVENT_STATE_ERROR) {
3064 * Detached SIBLING events cannot leave ERROR state.
3066 if (event->event_caps & PERF_EV_CAP_SIBLING &&
3067 event->group_leader == event)
3070 event->state = PERF_EVENT_STATE_OFF;
3072 raw_spin_unlock_irq(&ctx->lock);
3074 event_function_call(event, __perf_event_enable, NULL);
3078 * See perf_event_disable();
3080 void perf_event_enable(struct perf_event *event)
3082 struct perf_event_context *ctx;
3084 ctx = perf_event_ctx_lock(event);
3085 _perf_event_enable(event);
3086 perf_event_ctx_unlock(event, ctx);
3088 EXPORT_SYMBOL_GPL(perf_event_enable);
3090 struct stop_event_data {
3091 struct perf_event *event;
3092 unsigned int restart;
3095 static int __perf_event_stop(void *info)
3097 struct stop_event_data *sd = info;
3098 struct perf_event *event = sd->event;
3100 /* if it's already INACTIVE, do nothing */
3101 if (READ_ONCE(event->state) != PERF_EVENT_STATE_ACTIVE)
3104 /* matches smp_wmb() in event_sched_in() */
3108 * There is a window with interrupts enabled before we get here,
3109 * so we need to check again lest we try to stop another CPU's event.
3111 if (READ_ONCE(event->oncpu) != smp_processor_id())
3114 event->pmu->stop(event, PERF_EF_UPDATE);
3117 * May race with the actual stop (through perf_pmu_output_stop()),
3118 * but it is only used for events with AUX ring buffer, and such
3119 * events will refuse to restart because of rb::aux_mmap_count==0,
3120 * see comments in perf_aux_output_begin().
3122 * Since this is happening on an event-local CPU, no trace is lost
3126 event->pmu->start(event, 0);
3131 static int perf_event_stop(struct perf_event *event, int restart)
3133 struct stop_event_data sd = {
3140 if (READ_ONCE(event->state) != PERF_EVENT_STATE_ACTIVE)
3143 /* matches smp_wmb() in event_sched_in() */
3147 * We only want to restart ACTIVE events, so if the event goes
3148 * inactive here (event->oncpu==-1), there's nothing more to do;
3149 * fall through with ret==-ENXIO.
3151 ret = cpu_function_call(READ_ONCE(event->oncpu),
3152 __perf_event_stop, &sd);
3153 } while (ret == -EAGAIN);
3159 * In order to contain the amount of racy and tricky in the address filter
3160 * configuration management, it is a two part process:
3162 * (p1) when userspace mappings change as a result of (1) or (2) or (3) below,
3163 * we update the addresses of corresponding vmas in
3164 * event::addr_filter_ranges array and bump the event::addr_filters_gen;
3165 * (p2) when an event is scheduled in (pmu::add), it calls
3166 * perf_event_addr_filters_sync() which calls pmu::addr_filters_sync()
3167 * if the generation has changed since the previous call.
3169 * If (p1) happens while the event is active, we restart it to force (p2).
3171 * (1) perf_addr_filters_apply(): adjusting filters' offsets based on
3172 * pre-existing mappings, called once when new filters arrive via SET_FILTER
3174 * (2) perf_addr_filters_adjust(): adjusting filters' offsets based on newly
3175 * registered mapping, called for every new mmap(), with mm::mmap_lock down
3177 * (3) perf_event_addr_filters_exec(): clearing filters' offsets in the process
3180 void perf_event_addr_filters_sync(struct perf_event *event)
3182 struct perf_addr_filters_head *ifh = perf_event_addr_filters(event);
3184 if (!has_addr_filter(event))
3187 raw_spin_lock(&ifh->lock);
3188 if (event->addr_filters_gen != event->hw.addr_filters_gen) {
3189 event->pmu->addr_filters_sync(event);
3190 event->hw.addr_filters_gen = event->addr_filters_gen;
3192 raw_spin_unlock(&ifh->lock);
3194 EXPORT_SYMBOL_GPL(perf_event_addr_filters_sync);
3196 static int _perf_event_refresh(struct perf_event *event, int refresh)
3199 * not supported on inherited events
3201 if (event->attr.inherit || !is_sampling_event(event))
3204 atomic_add(refresh, &event->event_limit);
3205 _perf_event_enable(event);
3211 * See perf_event_disable()
3213 int perf_event_refresh(struct perf_event *event, int refresh)
3215 struct perf_event_context *ctx;
3218 ctx = perf_event_ctx_lock(event);
3219 ret = _perf_event_refresh(event, refresh);
3220 perf_event_ctx_unlock(event, ctx);
3224 EXPORT_SYMBOL_GPL(perf_event_refresh);
3226 static int perf_event_modify_breakpoint(struct perf_event *bp,
3227 struct perf_event_attr *attr)
3231 _perf_event_disable(bp);
3233 err = modify_user_hw_breakpoint_check(bp, attr, true);
3235 if (!bp->attr.disabled)
3236 _perf_event_enable(bp);
3242 * Copy event-type-independent attributes that may be modified.
3244 static void perf_event_modify_copy_attr(struct perf_event_attr *to,
3245 const struct perf_event_attr *from)
3247 to->sig_data = from->sig_data;
3250 static int perf_event_modify_attr(struct perf_event *event,
3251 struct perf_event_attr *attr)
3253 int (*func)(struct perf_event *, struct perf_event_attr *);
3254 struct perf_event *child;
3257 if (event->attr.type != attr->type)
3260 switch (event->attr.type) {
3261 case PERF_TYPE_BREAKPOINT:
3262 func = perf_event_modify_breakpoint;
3265 /* Place holder for future additions. */
3269 WARN_ON_ONCE(event->ctx->parent_ctx);
3271 mutex_lock(&event->child_mutex);
3273 * Event-type-independent attributes must be copied before event-type
3274 * modification, which will validate that final attributes match the
3275 * source attributes after all relevant attributes have been copied.
3277 perf_event_modify_copy_attr(&event->attr, attr);
3278 err = func(event, attr);
3281 list_for_each_entry(child, &event->child_list, child_list) {
3282 perf_event_modify_copy_attr(&child->attr, attr);
3283 err = func(child, attr);
3288 mutex_unlock(&event->child_mutex);
3292 static void ctx_sched_out(struct perf_event_context *ctx,
3293 struct perf_cpu_context *cpuctx,
3294 enum event_type_t event_type)
3296 struct perf_event *event, *tmp;
3297 int is_active = ctx->is_active;
3299 lockdep_assert_held(&ctx->lock);
3301 if (likely(!ctx->nr_events)) {
3303 * See __perf_remove_from_context().
3305 WARN_ON_ONCE(ctx->is_active);
3307 WARN_ON_ONCE(cpuctx->task_ctx);
3312 * Always update time if it was set; not only when it changes.
3313 * Otherwise we can 'forget' to update time for any but the last
3314 * context we sched out. For example:
3316 * ctx_sched_out(.event_type = EVENT_FLEXIBLE)
3317 * ctx_sched_out(.event_type = EVENT_PINNED)
3319 * would only update time for the pinned events.
3321 if (is_active & EVENT_TIME) {
3322 /* update (and stop) ctx time */
3323 update_context_time(ctx);
3324 update_cgrp_time_from_cpuctx(cpuctx, ctx == &cpuctx->ctx);
3326 * CPU-release for the below ->is_active store,
3327 * see __load_acquire() in perf_event_time_now()
3332 ctx->is_active &= ~event_type;
3333 if (!(ctx->is_active & EVENT_ALL))
3337 WARN_ON_ONCE(cpuctx->task_ctx != ctx);
3338 if (!ctx->is_active)
3339 cpuctx->task_ctx = NULL;
3342 is_active ^= ctx->is_active; /* changed bits */
3344 if (!ctx->nr_active || !(is_active & EVENT_ALL))
3347 perf_pmu_disable(ctx->pmu);
3348 if (is_active & EVENT_PINNED) {
3349 list_for_each_entry_safe(event, tmp, &ctx->pinned_active, active_list)
3350 group_sched_out(event, cpuctx, ctx);
3353 if (is_active & EVENT_FLEXIBLE) {
3354 list_for_each_entry_safe(event, tmp, &ctx->flexible_active, active_list)
3355 group_sched_out(event, cpuctx, ctx);
3358 * Since we cleared EVENT_FLEXIBLE, also clear
3359 * rotate_necessary, is will be reset by
3360 * ctx_flexible_sched_in() when needed.
3362 ctx->rotate_necessary = 0;
3364 perf_pmu_enable(ctx->pmu);
3368 * Test whether two contexts are equivalent, i.e. whether they have both been
3369 * cloned from the same version of the same context.
3371 * Equivalence is measured using a generation number in the context that is
3372 * incremented on each modification to it; see unclone_ctx(), list_add_event()
3373 * and list_del_event().
3375 static int context_equiv(struct perf_event_context *ctx1,
3376 struct perf_event_context *ctx2)
3378 lockdep_assert_held(&ctx1->lock);
3379 lockdep_assert_held(&ctx2->lock);
3381 /* Pinning disables the swap optimization */
3382 if (ctx1->pin_count || ctx2->pin_count)
3385 /* If ctx1 is the parent of ctx2 */
3386 if (ctx1 == ctx2->parent_ctx && ctx1->generation == ctx2->parent_gen)
3389 /* If ctx2 is the parent of ctx1 */
3390 if (ctx1->parent_ctx == ctx2 && ctx1->parent_gen == ctx2->generation)
3394 * If ctx1 and ctx2 have the same parent; we flatten the parent
3395 * hierarchy, see perf_event_init_context().
3397 if (ctx1->parent_ctx && ctx1->parent_ctx == ctx2->parent_ctx &&
3398 ctx1->parent_gen == ctx2->parent_gen)
3405 static void __perf_event_sync_stat(struct perf_event *event,
3406 struct perf_event *next_event)
3410 if (!event->attr.inherit_stat)
3414 * Update the event value, we cannot use perf_event_read()
3415 * because we're in the middle of a context switch and have IRQs
3416 * disabled, which upsets smp_call_function_single(), however
3417 * we know the event must be on the current CPU, therefore we
3418 * don't need to use it.
3420 if (event->state == PERF_EVENT_STATE_ACTIVE)
3421 event->pmu->read(event);
3423 perf_event_update_time(event);
3426 * In order to keep per-task stats reliable we need to flip the event
3427 * values when we flip the contexts.
3429 value = local64_read(&next_event->count);
3430 value = local64_xchg(&event->count, value);
3431 local64_set(&next_event->count, value);
3433 swap(event->total_time_enabled, next_event->total_time_enabled);
3434 swap(event->total_time_running, next_event->total_time_running);
3437 * Since we swizzled the values, update the user visible data too.
3439 perf_event_update_userpage(event);
3440 perf_event_update_userpage(next_event);
3443 static void perf_event_sync_stat(struct perf_event_context *ctx,
3444 struct perf_event_context *next_ctx)
3446 struct perf_event *event, *next_event;
3451 update_context_time(ctx);
3453 event = list_first_entry(&ctx->event_list,
3454 struct perf_event, event_entry);
3456 next_event = list_first_entry(&next_ctx->event_list,
3457 struct perf_event, event_entry);
3459 while (&event->event_entry != &ctx->event_list &&
3460 &next_event->event_entry != &next_ctx->event_list) {
3462 __perf_event_sync_stat(event, next_event);
3464 event = list_next_entry(event, event_entry);
3465 next_event = list_next_entry(next_event, event_entry);
3469 static void perf_event_context_sched_out(struct task_struct *task, int ctxn,
3470 struct task_struct *next)
3472 struct perf_event_context *ctx = task->perf_event_ctxp[ctxn];
3473 struct perf_event_context *next_ctx;
3474 struct perf_event_context *parent, *next_parent;
3475 struct perf_cpu_context *cpuctx;
3483 cpuctx = __get_cpu_context(ctx);
3484 if (!cpuctx->task_ctx)
3488 next_ctx = next->perf_event_ctxp[ctxn];
3492 parent = rcu_dereference(ctx->parent_ctx);
3493 next_parent = rcu_dereference(next_ctx->parent_ctx);
3495 /* If neither context have a parent context; they cannot be clones. */
3496 if (!parent && !next_parent)
3499 if (next_parent == ctx || next_ctx == parent || next_parent == parent) {
3501 * Looks like the two contexts are clones, so we might be
3502 * able to optimize the context switch. We lock both
3503 * contexts and check that they are clones under the
3504 * lock (including re-checking that neither has been
3505 * uncloned in the meantime). It doesn't matter which
3506 * order we take the locks because no other cpu could
3507 * be trying to lock both of these tasks.
3509 raw_spin_lock(&ctx->lock);
3510 raw_spin_lock_nested(&next_ctx->lock, SINGLE_DEPTH_NESTING);
3511 if (context_equiv(ctx, next_ctx)) {
3513 WRITE_ONCE(ctx->task, next);
3514 WRITE_ONCE(next_ctx->task, task);
3516 perf_pmu_disable(pmu);
3518 if (cpuctx->sched_cb_usage && pmu->sched_task)
3519 pmu->sched_task(ctx, false);
3522 * PMU specific parts of task perf context can require
3523 * additional synchronization. As an example of such
3524 * synchronization see implementation details of Intel
3525 * LBR call stack data profiling;
3527 if (pmu->swap_task_ctx)
3528 pmu->swap_task_ctx(ctx, next_ctx);
3530 swap(ctx->task_ctx_data, next_ctx->task_ctx_data);
3532 perf_pmu_enable(pmu);
3535 * RCU_INIT_POINTER here is safe because we've not
3536 * modified the ctx and the above modification of
3537 * ctx->task and ctx->task_ctx_data are immaterial
3538 * since those values are always verified under
3539 * ctx->lock which we're now holding.
3541 RCU_INIT_POINTER(task->perf_event_ctxp[ctxn], next_ctx);
3542 RCU_INIT_POINTER(next->perf_event_ctxp[ctxn], ctx);
3546 perf_event_sync_stat(ctx, next_ctx);
3548 raw_spin_unlock(&next_ctx->lock);
3549 raw_spin_unlock(&ctx->lock);
3555 raw_spin_lock(&ctx->lock);
3556 perf_pmu_disable(pmu);
3558 if (cpuctx->sched_cb_usage && pmu->sched_task)
3559 pmu->sched_task(ctx, false);
3560 task_ctx_sched_out(cpuctx, ctx, EVENT_ALL);
3562 perf_pmu_enable(pmu);
3563 raw_spin_unlock(&ctx->lock);
3567 static DEFINE_PER_CPU(struct list_head, sched_cb_list);
3569 void perf_sched_cb_dec(struct pmu *pmu)
3571 struct perf_cpu_context *cpuctx = this_cpu_ptr(pmu->pmu_cpu_context);
3573 this_cpu_dec(perf_sched_cb_usages);
3575 if (!--cpuctx->sched_cb_usage)
3576 list_del(&cpuctx->sched_cb_entry);
3580 void perf_sched_cb_inc(struct pmu *pmu)
3582 struct perf_cpu_context *cpuctx = this_cpu_ptr(pmu->pmu_cpu_context);
3584 if (!cpuctx->sched_cb_usage++)
3585 list_add(&cpuctx->sched_cb_entry, this_cpu_ptr(&sched_cb_list));
3587 this_cpu_inc(perf_sched_cb_usages);
3591 * This function provides the context switch callback to the lower code
3592 * layer. It is invoked ONLY when the context switch callback is enabled.
3594 * This callback is relevant even to per-cpu events; for example multi event
3595 * PEBS requires this to provide PID/TID information. This requires we flush
3596 * all queued PEBS records before we context switch to a new task.
3598 static void __perf_pmu_sched_task(struct perf_cpu_context *cpuctx, bool sched_in)
3602 pmu = cpuctx->ctx.pmu; /* software PMUs will not have sched_task */
3604 if (WARN_ON_ONCE(!pmu->sched_task))
3607 perf_ctx_lock(cpuctx, cpuctx->task_ctx);
3608 perf_pmu_disable(pmu);
3610 pmu->sched_task(cpuctx->task_ctx, sched_in);
3612 perf_pmu_enable(pmu);
3613 perf_ctx_unlock(cpuctx, cpuctx->task_ctx);
3616 static void perf_pmu_sched_task(struct task_struct *prev,
3617 struct task_struct *next,
3620 struct perf_cpu_context *cpuctx;
3625 list_for_each_entry(cpuctx, this_cpu_ptr(&sched_cb_list), sched_cb_entry) {
3626 /* will be handled in perf_event_context_sched_in/out */
3627 if (cpuctx->task_ctx)
3630 __perf_pmu_sched_task(cpuctx, sched_in);
3634 static void perf_event_switch(struct task_struct *task,
3635 struct task_struct *next_prev, bool sched_in);
3637 #define for_each_task_context_nr(ctxn) \
3638 for ((ctxn) = 0; (ctxn) < perf_nr_task_contexts; (ctxn)++)
3641 * Called from scheduler to remove the events of the current task,
3642 * with interrupts disabled.
3644 * We stop each event and update the event value in event->count.
3646 * This does not protect us against NMI, but disable()
3647 * sets the disabled bit in the control field of event _before_
3648 * accessing the event control register. If a NMI hits, then it will
3649 * not restart the event.
3651 void __perf_event_task_sched_out(struct task_struct *task,
3652 struct task_struct *next)
3656 if (__this_cpu_read(perf_sched_cb_usages))
3657 perf_pmu_sched_task(task, next, false);
3659 if (atomic_read(&nr_switch_events))
3660 perf_event_switch(task, next, false);
3662 for_each_task_context_nr(ctxn)
3663 perf_event_context_sched_out(task, ctxn, next);
3666 * if cgroup events exist on this CPU, then we need
3667 * to check if we have to switch out PMU state.
3668 * cgroup event are system-wide mode only
3670 if (atomic_read(this_cpu_ptr(&perf_cgroup_events)))
3671 perf_cgroup_sched_out(task, next);
3675 * Called with IRQs disabled
3677 static void cpu_ctx_sched_out(struct perf_cpu_context *cpuctx,
3678 enum event_type_t event_type)
3680 ctx_sched_out(&cpuctx->ctx, cpuctx, event_type);
3683 static bool perf_less_group_idx(const void *l, const void *r)
3685 const struct perf_event *le = *(const struct perf_event **)l;
3686 const struct perf_event *re = *(const struct perf_event **)r;
3688 return le->group_index < re->group_index;
3691 static void swap_ptr(void *l, void *r)
3693 void **lp = l, **rp = r;
3698 static const struct min_heap_callbacks perf_min_heap = {
3699 .elem_size = sizeof(struct perf_event *),
3700 .less = perf_less_group_idx,
3704 static void __heap_add(struct min_heap *heap, struct perf_event *event)
3706 struct perf_event **itrs = heap->data;
3709 itrs[heap->nr] = event;
3714 static noinline int visit_groups_merge(struct perf_cpu_context *cpuctx,
3715 struct perf_event_groups *groups, int cpu,
3716 int (*func)(struct perf_event *, void *),
3719 #ifdef CONFIG_CGROUP_PERF
3720 struct cgroup_subsys_state *css = NULL;
3722 /* Space for per CPU and/or any CPU event iterators. */
3723 struct perf_event *itrs[2];
3724 struct min_heap event_heap;
3725 struct perf_event **evt;
3729 event_heap = (struct min_heap){
3730 .data = cpuctx->heap,
3732 .size = cpuctx->heap_size,
3735 lockdep_assert_held(&cpuctx->ctx.lock);
3737 #ifdef CONFIG_CGROUP_PERF
3739 css = &cpuctx->cgrp->css;
3742 event_heap = (struct min_heap){
3745 .size = ARRAY_SIZE(itrs),
3747 /* Events not within a CPU context may be on any CPU. */
3748 __heap_add(&event_heap, perf_event_groups_first(groups, -1, NULL));
3750 evt = event_heap.data;
3752 __heap_add(&event_heap, perf_event_groups_first(groups, cpu, NULL));
3754 #ifdef CONFIG_CGROUP_PERF
3755 for (; css; css = css->parent)
3756 __heap_add(&event_heap, perf_event_groups_first(groups, cpu, css->cgroup));
3759 min_heapify_all(&event_heap, &perf_min_heap);
3761 while (event_heap.nr) {
3762 ret = func(*evt, data);
3766 *evt = perf_event_groups_next(*evt);
3768 min_heapify(&event_heap, 0, &perf_min_heap);
3770 min_heap_pop(&event_heap, &perf_min_heap);
3777 * Because the userpage is strictly per-event (there is no concept of context,
3778 * so there cannot be a context indirection), every userpage must be updated
3779 * when context time starts :-(
3781 * IOW, we must not miss EVENT_TIME edges.
3783 static inline bool event_update_userpage(struct perf_event *event)
3785 if (likely(!atomic_read(&event->mmap_count)))
3788 perf_event_update_time(event);
3789 perf_event_update_userpage(event);
3794 static inline void group_update_userpage(struct perf_event *group_event)
3796 struct perf_event *event;
3798 if (!event_update_userpage(group_event))
3801 for_each_sibling_event(event, group_event)
3802 event_update_userpage(event);
3805 static int merge_sched_in(struct perf_event *event, void *data)
3807 struct perf_event_context *ctx = event->ctx;
3808 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
3809 int *can_add_hw = data;
3811 if (event->state <= PERF_EVENT_STATE_OFF)
3814 if (!event_filter_match(event))
3817 if (group_can_go_on(event, cpuctx, *can_add_hw)) {
3818 if (!group_sched_in(event, cpuctx, ctx))
3819 list_add_tail(&event->active_list, get_event_list(event));
3822 if (event->state == PERF_EVENT_STATE_INACTIVE) {
3824 if (event->attr.pinned) {
3825 perf_cgroup_event_disable(event, ctx);
3826 perf_event_set_state(event, PERF_EVENT_STATE_ERROR);
3828 ctx->rotate_necessary = 1;
3829 perf_mux_hrtimer_restart(cpuctx);
3830 group_update_userpage(event);
3838 ctx_pinned_sched_in(struct perf_event_context *ctx,
3839 struct perf_cpu_context *cpuctx)
3843 if (ctx != &cpuctx->ctx)
3846 visit_groups_merge(cpuctx, &ctx->pinned_groups,
3848 merge_sched_in, &can_add_hw);
3852 ctx_flexible_sched_in(struct perf_event_context *ctx,
3853 struct perf_cpu_context *cpuctx)
3857 if (ctx != &cpuctx->ctx)
3860 visit_groups_merge(cpuctx, &ctx->flexible_groups,
3862 merge_sched_in, &can_add_hw);
3866 ctx_sched_in(struct perf_event_context *ctx,
3867 struct perf_cpu_context *cpuctx,
3868 enum event_type_t event_type,
3869 struct task_struct *task)
3871 int is_active = ctx->is_active;
3873 lockdep_assert_held(&ctx->lock);
3875 if (likely(!ctx->nr_events))
3878 if (is_active ^ EVENT_TIME) {
3879 /* start ctx time */
3880 __update_context_time(ctx, false);
3881 perf_cgroup_set_timestamp(task, ctx);
3883 * CPU-release for the below ->is_active store,
3884 * see __load_acquire() in perf_event_time_now()
3889 ctx->is_active |= (event_type | EVENT_TIME);
3892 cpuctx->task_ctx = ctx;
3894 WARN_ON_ONCE(cpuctx->task_ctx != ctx);
3897 is_active ^= ctx->is_active; /* changed bits */
3900 * First go through the list and put on any pinned groups
3901 * in order to give them the best chance of going on.
3903 if (is_active & EVENT_PINNED)
3904 ctx_pinned_sched_in(ctx, cpuctx);
3906 /* Then walk through the lower prio flexible groups */
3907 if (is_active & EVENT_FLEXIBLE)
3908 ctx_flexible_sched_in(ctx, cpuctx);
3911 static void cpu_ctx_sched_in(struct perf_cpu_context *cpuctx,
3912 enum event_type_t event_type,
3913 struct task_struct *task)
3915 struct perf_event_context *ctx = &cpuctx->ctx;
3917 ctx_sched_in(ctx, cpuctx, event_type, task);
3920 static void perf_event_context_sched_in(struct perf_event_context *ctx,
3921 struct task_struct *task)
3923 struct perf_cpu_context *cpuctx;
3926 cpuctx = __get_cpu_context(ctx);
3929 * HACK: for HETEROGENEOUS the task context might have switched to a
3930 * different PMU, force (re)set the context,
3932 pmu = ctx->pmu = cpuctx->ctx.pmu;
3934 if (cpuctx->task_ctx == ctx) {
3935 if (cpuctx->sched_cb_usage)
3936 __perf_pmu_sched_task(cpuctx, true);
3940 perf_ctx_lock(cpuctx, ctx);
3942 * We must check ctx->nr_events while holding ctx->lock, such
3943 * that we serialize against perf_install_in_context().
3945 if (!ctx->nr_events)
3948 perf_pmu_disable(pmu);
3950 * We want to keep the following priority order:
3951 * cpu pinned (that don't need to move), task pinned,
3952 * cpu flexible, task flexible.
3954 * However, if task's ctx is not carrying any pinned
3955 * events, no need to flip the cpuctx's events around.
3957 if (!RB_EMPTY_ROOT(&ctx->pinned_groups.tree))
3958 cpu_ctx_sched_out(cpuctx, EVENT_FLEXIBLE);
3959 perf_event_sched_in(cpuctx, ctx, task);
3961 if (cpuctx->sched_cb_usage && pmu->sched_task)
3962 pmu->sched_task(cpuctx->task_ctx, true);
3964 perf_pmu_enable(pmu);
3967 perf_ctx_unlock(cpuctx, ctx);
3971 * Called from scheduler to add the events of the current task
3972 * with interrupts disabled.
3974 * We restore the event value and then enable it.
3976 * This does not protect us against NMI, but enable()
3977 * sets the enabled bit in the control field of event _before_
3978 * accessing the event control register. If a NMI hits, then it will
3979 * keep the event running.
3981 void __perf_event_task_sched_in(struct task_struct *prev,
3982 struct task_struct *task)
3984 struct perf_event_context *ctx;
3988 * If cgroup events exist on this CPU, then we need to check if we have
3989 * to switch in PMU state; cgroup event are system-wide mode only.
3991 * Since cgroup events are CPU events, we must schedule these in before
3992 * we schedule in the task events.
3994 if (atomic_read(this_cpu_ptr(&perf_cgroup_events)))
3995 perf_cgroup_sched_in(prev, task);
3997 for_each_task_context_nr(ctxn) {
3998 ctx = task->perf_event_ctxp[ctxn];
4002 perf_event_context_sched_in(ctx, task);
4005 if (atomic_read(&nr_switch_events))
4006 perf_event_switch(task, prev, true);
4008 if (__this_cpu_read(perf_sched_cb_usages))
4009 perf_pmu_sched_task(prev, task, true);
4012 static u64 perf_calculate_period(struct perf_event *event, u64 nsec, u64 count)
4014 u64 frequency = event->attr.sample_freq;
4015 u64 sec = NSEC_PER_SEC;
4016 u64 divisor, dividend;
4018 int count_fls, nsec_fls, frequency_fls, sec_fls;
4020 count_fls = fls64(count);
4021 nsec_fls = fls64(nsec);
4022 frequency_fls = fls64(frequency);
4026 * We got @count in @nsec, with a target of sample_freq HZ
4027 * the target period becomes:
4030 * period = -------------------
4031 * @nsec * sample_freq
4036 * Reduce accuracy by one bit such that @a and @b converge
4037 * to a similar magnitude.
4039 #define REDUCE_FLS(a, b) \
4041 if (a##_fls > b##_fls) { \
4051 * Reduce accuracy until either term fits in a u64, then proceed with
4052 * the other, so that finally we can do a u64/u64 division.
4054 while (count_fls + sec_fls > 64 && nsec_fls + frequency_fls > 64) {
4055 REDUCE_FLS(nsec, frequency);
4056 REDUCE_FLS(sec, count);
4059 if (count_fls + sec_fls > 64) {
4060 divisor = nsec * frequency;
4062 while (count_fls + sec_fls > 64) {
4063 REDUCE_FLS(count, sec);
4067 dividend = count * sec;
4069 dividend = count * sec;
4071 while (nsec_fls + frequency_fls > 64) {
4072 REDUCE_FLS(nsec, frequency);
4076 divisor = nsec * frequency;
4082 return div64_u64(dividend, divisor);
4085 static DEFINE_PER_CPU(int, perf_throttled_count);
4086 static DEFINE_PER_CPU(u64, perf_throttled_seq);
4088 static void perf_adjust_period(struct perf_event *event, u64 nsec, u64 count, bool disable)
4090 struct hw_perf_event *hwc = &event->hw;
4091 s64 period, sample_period;
4094 period = perf_calculate_period(event, nsec, count);
4096 delta = (s64)(period - hwc->sample_period);
4097 delta = (delta + 7) / 8; /* low pass filter */
4099 sample_period = hwc->sample_period + delta;
4104 hwc->sample_period = sample_period;
4106 if (local64_read(&hwc->period_left) > 8*sample_period) {
4108 event->pmu->stop(event, PERF_EF_UPDATE);
4110 local64_set(&hwc->period_left, 0);
4113 event->pmu->start(event, PERF_EF_RELOAD);
4118 * combine freq adjustment with unthrottling to avoid two passes over the
4119 * events. At the same time, make sure, having freq events does not change
4120 * the rate of unthrottling as that would introduce bias.
4122 static void perf_adjust_freq_unthr_context(struct perf_event_context *ctx,
4125 struct perf_event *event;
4126 struct hw_perf_event *hwc;
4127 u64 now, period = TICK_NSEC;
4131 * only need to iterate over all events iff:
4132 * - context have events in frequency mode (needs freq adjust)
4133 * - there are events to unthrottle on this cpu
4135 if (!(ctx->nr_freq || needs_unthr))
4138 raw_spin_lock(&ctx->lock);
4139 perf_pmu_disable(ctx->pmu);
4141 list_for_each_entry_rcu(event, &ctx->event_list, event_entry) {
4142 if (event->state != PERF_EVENT_STATE_ACTIVE)
4145 if (!event_filter_match(event))
4148 perf_pmu_disable(event->pmu);
4152 if (hwc->interrupts == MAX_INTERRUPTS) {
4153 hwc->interrupts = 0;
4154 perf_log_throttle(event, 1);
4155 event->pmu->start(event, 0);
4158 if (!event->attr.freq || !event->attr.sample_freq)
4162 * stop the event and update event->count
4164 event->pmu->stop(event, PERF_EF_UPDATE);
4166 now = local64_read(&event->count);
4167 delta = now - hwc->freq_count_stamp;
4168 hwc->freq_count_stamp = now;
4172 * reload only if value has changed
4173 * we have stopped the event so tell that
4174 * to perf_adjust_period() to avoid stopping it
4178 perf_adjust_period(event, period, delta, false);
4180 event->pmu->start(event, delta > 0 ? PERF_EF_RELOAD : 0);
4182 perf_pmu_enable(event->pmu);
4185 perf_pmu_enable(ctx->pmu);
4186 raw_spin_unlock(&ctx->lock);
4190 * Move @event to the tail of the @ctx's elegible events.
4192 static void rotate_ctx(struct perf_event_context *ctx, struct perf_event *event)
4195 * Rotate the first entry last of non-pinned groups. Rotation might be
4196 * disabled by the inheritance code.
4198 if (ctx->rotate_disable)
4201 perf_event_groups_delete(&ctx->flexible_groups, event);
4202 perf_event_groups_insert(&ctx->flexible_groups, event);
4205 /* pick an event from the flexible_groups to rotate */
4206 static inline struct perf_event *
4207 ctx_event_to_rotate(struct perf_event_context *ctx)
4209 struct perf_event *event;
4211 /* pick the first active flexible event */
4212 event = list_first_entry_or_null(&ctx->flexible_active,
4213 struct perf_event, active_list);
4215 /* if no active flexible event, pick the first event */
4217 event = rb_entry_safe(rb_first(&ctx->flexible_groups.tree),
4218 typeof(*event), group_node);
4222 * Unconditionally clear rotate_necessary; if ctx_flexible_sched_in()
4223 * finds there are unschedulable events, it will set it again.
4225 ctx->rotate_necessary = 0;
4230 static bool perf_rotate_context(struct perf_cpu_context *cpuctx)
4232 struct perf_event *cpu_event = NULL, *task_event = NULL;
4233 struct perf_event_context *task_ctx = NULL;
4234 int cpu_rotate, task_rotate;
4237 * Since we run this from IRQ context, nobody can install new
4238 * events, thus the event count values are stable.
4241 cpu_rotate = cpuctx->ctx.rotate_necessary;
4242 task_ctx = cpuctx->task_ctx;
4243 task_rotate = task_ctx ? task_ctx->rotate_necessary : 0;
4245 if (!(cpu_rotate || task_rotate))
4248 perf_ctx_lock(cpuctx, cpuctx->task_ctx);
4249 perf_pmu_disable(cpuctx->ctx.pmu);
4252 task_event = ctx_event_to_rotate(task_ctx);
4254 cpu_event = ctx_event_to_rotate(&cpuctx->ctx);
4257 * As per the order given at ctx_resched() first 'pop' task flexible
4258 * and then, if needed CPU flexible.
4260 if (task_event || (task_ctx && cpu_event))
4261 ctx_sched_out(task_ctx, cpuctx, EVENT_FLEXIBLE);
4263 cpu_ctx_sched_out(cpuctx, EVENT_FLEXIBLE);
4266 rotate_ctx(task_ctx, task_event);
4268 rotate_ctx(&cpuctx->ctx, cpu_event);
4270 perf_event_sched_in(cpuctx, task_ctx, current);
4272 perf_pmu_enable(cpuctx->ctx.pmu);
4273 perf_ctx_unlock(cpuctx, cpuctx->task_ctx);
4278 void perf_event_task_tick(void)
4280 struct list_head *head = this_cpu_ptr(&active_ctx_list);
4281 struct perf_event_context *ctx, *tmp;
4284 lockdep_assert_irqs_disabled();
4286 __this_cpu_inc(perf_throttled_seq);
4287 throttled = __this_cpu_xchg(perf_throttled_count, 0);
4288 tick_dep_clear_cpu(smp_processor_id(), TICK_DEP_BIT_PERF_EVENTS);
4290 list_for_each_entry_safe(ctx, tmp, head, active_ctx_list)
4291 perf_adjust_freq_unthr_context(ctx, throttled);
4294 static int event_enable_on_exec(struct perf_event *event,
4295 struct perf_event_context *ctx)
4297 if (!event->attr.enable_on_exec)
4300 event->attr.enable_on_exec = 0;
4301 if (event->state >= PERF_EVENT_STATE_INACTIVE)
4304 perf_event_set_state(event, PERF_EVENT_STATE_INACTIVE);
4310 * Enable all of a task's events that have been marked enable-on-exec.
4311 * This expects task == current.
4313 static void perf_event_enable_on_exec(int ctxn)
4315 struct perf_event_context *ctx, *clone_ctx = NULL;
4316 enum event_type_t event_type = 0;
4317 struct perf_cpu_context *cpuctx;
4318 struct perf_event *event;
4319 unsigned long flags;
4322 local_irq_save(flags);
4323 ctx = current->perf_event_ctxp[ctxn];
4324 if (!ctx || !ctx->nr_events)
4327 cpuctx = __get_cpu_context(ctx);
4328 perf_ctx_lock(cpuctx, ctx);
4329 ctx_sched_out(ctx, cpuctx, EVENT_TIME);
4330 list_for_each_entry(event, &ctx->event_list, event_entry) {
4331 enabled |= event_enable_on_exec(event, ctx);
4332 event_type |= get_event_type(event);
4336 * Unclone and reschedule this context if we enabled any event.
4339 clone_ctx = unclone_ctx(ctx);
4340 ctx_resched(cpuctx, ctx, event_type);
4342 ctx_sched_in(ctx, cpuctx, EVENT_TIME, current);
4344 perf_ctx_unlock(cpuctx, ctx);
4347 local_irq_restore(flags);
4353 static void perf_remove_from_owner(struct perf_event *event);
4354 static void perf_event_exit_event(struct perf_event *event,
4355 struct perf_event_context *ctx);
4358 * Removes all events from the current task that have been marked
4359 * remove-on-exec, and feeds their values back to parent events.
4361 static void perf_event_remove_on_exec(int ctxn)
4363 struct perf_event_context *ctx, *clone_ctx = NULL;
4364 struct perf_event *event, *next;
4365 LIST_HEAD(free_list);
4366 unsigned long flags;
4367 bool modified = false;
4369 ctx = perf_pin_task_context(current, ctxn);
4373 mutex_lock(&ctx->mutex);
4375 if (WARN_ON_ONCE(ctx->task != current))
4378 list_for_each_entry_safe(event, next, &ctx->event_list, event_entry) {
4379 if (!event->attr.remove_on_exec)
4382 if (!is_kernel_event(event))
4383 perf_remove_from_owner(event);
4387 perf_event_exit_event(event, ctx);
4390 raw_spin_lock_irqsave(&ctx->lock, flags);
4392 clone_ctx = unclone_ctx(ctx);
4394 raw_spin_unlock_irqrestore(&ctx->lock, flags);
4397 mutex_unlock(&ctx->mutex);
4404 struct perf_read_data {
4405 struct perf_event *event;
4410 static int __perf_event_read_cpu(struct perf_event *event, int event_cpu)
4412 u16 local_pkg, event_pkg;
4414 if (event->group_caps & PERF_EV_CAP_READ_ACTIVE_PKG) {
4415 int local_cpu = smp_processor_id();
4417 event_pkg = topology_physical_package_id(event_cpu);
4418 local_pkg = topology_physical_package_id(local_cpu);
4420 if (event_pkg == local_pkg)
4428 * Cross CPU call to read the hardware event
4430 static void __perf_event_read(void *info)
4432 struct perf_read_data *data = info;
4433 struct perf_event *sub, *event = data->event;
4434 struct perf_event_context *ctx = event->ctx;
4435 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
4436 struct pmu *pmu = event->pmu;
4439 * If this is a task context, we need to check whether it is
4440 * the current task context of this cpu. If not it has been
4441 * scheduled out before the smp call arrived. In that case
4442 * event->count would have been updated to a recent sample
4443 * when the event was scheduled out.
4445 if (ctx->task && cpuctx->task_ctx != ctx)
4448 raw_spin_lock(&ctx->lock);
4449 if (ctx->is_active & EVENT_TIME) {
4450 update_context_time(ctx);
4451 update_cgrp_time_from_event(event);
4454 perf_event_update_time(event);
4456 perf_event_update_sibling_time(event);
4458 if (event->state != PERF_EVENT_STATE_ACTIVE)
4467 pmu->start_txn(pmu, PERF_PMU_TXN_READ);
4471 for_each_sibling_event(sub, event) {
4472 if (sub->state == PERF_EVENT_STATE_ACTIVE) {
4474 * Use sibling's PMU rather than @event's since
4475 * sibling could be on different (eg: software) PMU.
4477 sub->pmu->read(sub);
4481 data->ret = pmu->commit_txn(pmu);
4484 raw_spin_unlock(&ctx->lock);
4487 static inline u64 perf_event_count(struct perf_event *event)
4489 return local64_read(&event->count) + atomic64_read(&event->child_count);
4492 static void calc_timer_values(struct perf_event *event,
4499 *now = perf_clock();
4500 ctx_time = perf_event_time_now(event, *now);
4501 __perf_update_times(event, ctx_time, enabled, running);
4505 * NMI-safe method to read a local event, that is an event that
4507 * - either for the current task, or for this CPU
4508 * - does not have inherit set, for inherited task events
4509 * will not be local and we cannot read them atomically
4510 * - must not have a pmu::count method
4512 int perf_event_read_local(struct perf_event *event, u64 *value,
4513 u64 *enabled, u64 *running)
4515 unsigned long flags;
4519 * Disabling interrupts avoids all counter scheduling (context
4520 * switches, timer based rotation and IPIs).
4522 local_irq_save(flags);
4525 * It must not be an event with inherit set, we cannot read
4526 * all child counters from atomic context.
4528 if (event->attr.inherit) {
4533 /* If this is a per-task event, it must be for current */
4534 if ((event->attach_state & PERF_ATTACH_TASK) &&
4535 event->hw.target != current) {
4540 /* If this is a per-CPU event, it must be for this CPU */
4541 if (!(event->attach_state & PERF_ATTACH_TASK) &&
4542 event->cpu != smp_processor_id()) {
4547 /* If this is a pinned event it must be running on this CPU */
4548 if (event->attr.pinned && event->oncpu != smp_processor_id()) {
4554 * If the event is currently on this CPU, its either a per-task event,
4555 * or local to this CPU. Furthermore it means its ACTIVE (otherwise
4558 if (event->oncpu == smp_processor_id())
4559 event->pmu->read(event);
4561 *value = local64_read(&event->count);
4562 if (enabled || running) {
4563 u64 __enabled, __running, __now;;
4565 calc_timer_values(event, &__now, &__enabled, &__running);
4567 *enabled = __enabled;
4569 *running = __running;
4572 local_irq_restore(flags);
4577 static int perf_event_read(struct perf_event *event, bool group)
4579 enum perf_event_state state = READ_ONCE(event->state);
4580 int event_cpu, ret = 0;
4583 * If event is enabled and currently active on a CPU, update the
4584 * value in the event structure:
4587 if (state == PERF_EVENT_STATE_ACTIVE) {
4588 struct perf_read_data data;
4591 * Orders the ->state and ->oncpu loads such that if we see
4592 * ACTIVE we must also see the right ->oncpu.
4594 * Matches the smp_wmb() from event_sched_in().
4598 event_cpu = READ_ONCE(event->oncpu);
4599 if ((unsigned)event_cpu >= nr_cpu_ids)
4602 data = (struct perf_read_data){
4609 event_cpu = __perf_event_read_cpu(event, event_cpu);
4612 * Purposely ignore the smp_call_function_single() return
4615 * If event_cpu isn't a valid CPU it means the event got
4616 * scheduled out and that will have updated the event count.
4618 * Therefore, either way, we'll have an up-to-date event count
4621 (void)smp_call_function_single(event_cpu, __perf_event_read, &data, 1);
4625 } else if (state == PERF_EVENT_STATE_INACTIVE) {
4626 struct perf_event_context *ctx = event->ctx;
4627 unsigned long flags;
4629 raw_spin_lock_irqsave(&ctx->lock, flags);
4630 state = event->state;
4631 if (state != PERF_EVENT_STATE_INACTIVE) {
4632 raw_spin_unlock_irqrestore(&ctx->lock, flags);
4637 * May read while context is not active (e.g., thread is
4638 * blocked), in that case we cannot update context time
4640 if (ctx->is_active & EVENT_TIME) {
4641 update_context_time(ctx);
4642 update_cgrp_time_from_event(event);
4645 perf_event_update_time(event);
4647 perf_event_update_sibling_time(event);
4648 raw_spin_unlock_irqrestore(&ctx->lock, flags);
4655 * Initialize the perf_event context in a task_struct:
4657 static void __perf_event_init_context(struct perf_event_context *ctx)
4659 raw_spin_lock_init(&ctx->lock);
4660 mutex_init(&ctx->mutex);
4661 INIT_LIST_HEAD(&ctx->active_ctx_list);
4662 perf_event_groups_init(&ctx->pinned_groups);
4663 perf_event_groups_init(&ctx->flexible_groups);
4664 INIT_LIST_HEAD(&ctx->event_list);
4665 INIT_LIST_HEAD(&ctx->pinned_active);
4666 INIT_LIST_HEAD(&ctx->flexible_active);
4667 refcount_set(&ctx->refcount, 1);
4670 static struct perf_event_context *
4671 alloc_perf_context(struct pmu *pmu, struct task_struct *task)
4673 struct perf_event_context *ctx;
4675 ctx = kzalloc(sizeof(struct perf_event_context), GFP_KERNEL);
4679 __perf_event_init_context(ctx);
4681 ctx->task = get_task_struct(task);
4687 static struct task_struct *
4688 find_lively_task_by_vpid(pid_t vpid)
4690 struct task_struct *task;
4696 task = find_task_by_vpid(vpid);
4698 get_task_struct(task);
4702 return ERR_PTR(-ESRCH);
4708 * Returns a matching context with refcount and pincount.
4710 static struct perf_event_context *
4711 find_get_context(struct pmu *pmu, struct task_struct *task,
4712 struct perf_event *event)
4714 struct perf_event_context *ctx, *clone_ctx = NULL;
4715 struct perf_cpu_context *cpuctx;
4716 void *task_ctx_data = NULL;
4717 unsigned long flags;
4719 int cpu = event->cpu;
4722 /* Must be root to operate on a CPU event: */
4723 err = perf_allow_cpu(&event->attr);
4725 return ERR_PTR(err);
4727 cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
4730 raw_spin_lock_irqsave(&ctx->lock, flags);
4732 raw_spin_unlock_irqrestore(&ctx->lock, flags);
4738 ctxn = pmu->task_ctx_nr;
4742 if (event->attach_state & PERF_ATTACH_TASK_DATA) {
4743 task_ctx_data = alloc_task_ctx_data(pmu);
4744 if (!task_ctx_data) {
4751 ctx = perf_lock_task_context(task, ctxn, &flags);
4753 clone_ctx = unclone_ctx(ctx);
4756 if (task_ctx_data && !ctx->task_ctx_data) {
4757 ctx->task_ctx_data = task_ctx_data;
4758 task_ctx_data = NULL;
4760 raw_spin_unlock_irqrestore(&ctx->lock, flags);
4765 ctx = alloc_perf_context(pmu, task);
4770 if (task_ctx_data) {
4771 ctx->task_ctx_data = task_ctx_data;
4772 task_ctx_data = NULL;
4776 mutex_lock(&task->perf_event_mutex);
4778 * If it has already passed perf_event_exit_task().
4779 * we must see PF_EXITING, it takes this mutex too.
4781 if (task->flags & PF_EXITING)
4783 else if (task->perf_event_ctxp[ctxn])
4788 rcu_assign_pointer(task->perf_event_ctxp[ctxn], ctx);
4790 mutex_unlock(&task->perf_event_mutex);
4792 if (unlikely(err)) {
4801 free_task_ctx_data(pmu, task_ctx_data);
4805 free_task_ctx_data(pmu, task_ctx_data);
4806 return ERR_PTR(err);
4809 static void perf_event_free_filter(struct perf_event *event);
4811 static void free_event_rcu(struct rcu_head *head)
4813 struct perf_event *event;
4815 event = container_of(head, struct perf_event, rcu_head);
4817 put_pid_ns(event->ns);
4818 perf_event_free_filter(event);
4819 kmem_cache_free(perf_event_cache, event);
4822 static void ring_buffer_attach(struct perf_event *event,
4823 struct perf_buffer *rb);
4825 static void detach_sb_event(struct perf_event *event)
4827 struct pmu_event_list *pel = per_cpu_ptr(&pmu_sb_events, event->cpu);
4829 raw_spin_lock(&pel->lock);
4830 list_del_rcu(&event->sb_list);
4831 raw_spin_unlock(&pel->lock);
4834 static bool is_sb_event(struct perf_event *event)
4836 struct perf_event_attr *attr = &event->attr;
4841 if (event->attach_state & PERF_ATTACH_TASK)
4844 if (attr->mmap || attr->mmap_data || attr->mmap2 ||
4845 attr->comm || attr->comm_exec ||
4846 attr->task || attr->ksymbol ||
4847 attr->context_switch || attr->text_poke ||
4853 static void unaccount_pmu_sb_event(struct perf_event *event)
4855 if (is_sb_event(event))
4856 detach_sb_event(event);
4859 static void unaccount_event_cpu(struct perf_event *event, int cpu)
4864 if (is_cgroup_event(event))
4865 atomic_dec(&per_cpu(perf_cgroup_events, cpu));
4868 #ifdef CONFIG_NO_HZ_FULL
4869 static DEFINE_SPINLOCK(nr_freq_lock);
4872 static void unaccount_freq_event_nohz(void)
4874 #ifdef CONFIG_NO_HZ_FULL
4875 spin_lock(&nr_freq_lock);
4876 if (atomic_dec_and_test(&nr_freq_events))
4877 tick_nohz_dep_clear(TICK_DEP_BIT_PERF_EVENTS);
4878 spin_unlock(&nr_freq_lock);
4882 static void unaccount_freq_event(void)
4884 if (tick_nohz_full_enabled())
4885 unaccount_freq_event_nohz();
4887 atomic_dec(&nr_freq_events);
4890 static void unaccount_event(struct perf_event *event)
4897 if (event->attach_state & (PERF_ATTACH_TASK | PERF_ATTACH_SCHED_CB))
4899 if (event->attr.mmap || event->attr.mmap_data)
4900 atomic_dec(&nr_mmap_events);
4901 if (event->attr.build_id)
4902 atomic_dec(&nr_build_id_events);
4903 if (event->attr.comm)
4904 atomic_dec(&nr_comm_events);
4905 if (event->attr.namespaces)
4906 atomic_dec(&nr_namespaces_events);
4907 if (event->attr.cgroup)
4908 atomic_dec(&nr_cgroup_events);
4909 if (event->attr.task)
4910 atomic_dec(&nr_task_events);
4911 if (event->attr.freq)
4912 unaccount_freq_event();
4913 if (event->attr.context_switch) {
4915 atomic_dec(&nr_switch_events);
4917 if (is_cgroup_event(event))
4919 if (has_branch_stack(event))
4921 if (event->attr.ksymbol)
4922 atomic_dec(&nr_ksymbol_events);
4923 if (event->attr.bpf_event)
4924 atomic_dec(&nr_bpf_events);
4925 if (event->attr.text_poke)
4926 atomic_dec(&nr_text_poke_events);
4929 if (!atomic_add_unless(&perf_sched_count, -1, 1))
4930 schedule_delayed_work(&perf_sched_work, HZ);
4933 unaccount_event_cpu(event, event->cpu);
4935 unaccount_pmu_sb_event(event);
4938 static void perf_sched_delayed(struct work_struct *work)
4940 mutex_lock(&perf_sched_mutex);
4941 if (atomic_dec_and_test(&perf_sched_count))
4942 static_branch_disable(&perf_sched_events);
4943 mutex_unlock(&perf_sched_mutex);
4947 * The following implement mutual exclusion of events on "exclusive" pmus
4948 * (PERF_PMU_CAP_EXCLUSIVE). Such pmus can only have one event scheduled
4949 * at a time, so we disallow creating events that might conflict, namely:
4951 * 1) cpu-wide events in the presence of per-task events,
4952 * 2) per-task events in the presence of cpu-wide events,
4953 * 3) two matching events on the same context.
4955 * The former two cases are handled in the allocation path (perf_event_alloc(),
4956 * _free_event()), the latter -- before the first perf_install_in_context().
4958 static int exclusive_event_init(struct perf_event *event)
4960 struct pmu *pmu = event->pmu;
4962 if (!is_exclusive_pmu(pmu))
4966 * Prevent co-existence of per-task and cpu-wide events on the
4967 * same exclusive pmu.
4969 * Negative pmu::exclusive_cnt means there are cpu-wide
4970 * events on this "exclusive" pmu, positive means there are
4973 * Since this is called in perf_event_alloc() path, event::ctx
4974 * doesn't exist yet; it is, however, safe to use PERF_ATTACH_TASK
4975 * to mean "per-task event", because unlike other attach states it
4976 * never gets cleared.
4978 if (event->attach_state & PERF_ATTACH_TASK) {
4979 if (!atomic_inc_unless_negative(&pmu->exclusive_cnt))
4982 if (!atomic_dec_unless_positive(&pmu->exclusive_cnt))
4989 static void exclusive_event_destroy(struct perf_event *event)
4991 struct pmu *pmu = event->pmu;
4993 if (!is_exclusive_pmu(pmu))
4996 /* see comment in exclusive_event_init() */
4997 if (event->attach_state & PERF_ATTACH_TASK)
4998 atomic_dec(&pmu->exclusive_cnt);
5000 atomic_inc(&pmu->exclusive_cnt);
5003 static bool exclusive_event_match(struct perf_event *e1, struct perf_event *e2)
5005 if ((e1->pmu == e2->pmu) &&
5006 (e1->cpu == e2->cpu ||
5013 static bool exclusive_event_installable(struct perf_event *event,
5014 struct perf_event_context *ctx)
5016 struct perf_event *iter_event;
5017 struct pmu *pmu = event->pmu;
5019 lockdep_assert_held(&ctx->mutex);
5021 if (!is_exclusive_pmu(pmu))
5024 list_for_each_entry(iter_event, &ctx->event_list, event_entry) {
5025 if (exclusive_event_match(iter_event, event))
5032 static void perf_addr_filters_splice(struct perf_event *event,
5033 struct list_head *head);
5035 static void _free_event(struct perf_event *event)
5037 irq_work_sync(&event->pending);
5039 unaccount_event(event);
5041 security_perf_event_free(event);
5045 * Can happen when we close an event with re-directed output.
5047 * Since we have a 0 refcount, perf_mmap_close() will skip
5048 * over us; possibly making our ring_buffer_put() the last.
5050 mutex_lock(&event->mmap_mutex);
5051 ring_buffer_attach(event, NULL);
5052 mutex_unlock(&event->mmap_mutex);
5055 if (is_cgroup_event(event))
5056 perf_detach_cgroup(event);
5058 if (!event->parent) {
5059 if (event->attr.sample_type & PERF_SAMPLE_CALLCHAIN)
5060 put_callchain_buffers();
5063 perf_event_free_bpf_prog(event);
5064 perf_addr_filters_splice(event, NULL);
5065 kfree(event->addr_filter_ranges);
5068 event->destroy(event);
5071 * Must be after ->destroy(), due to uprobe_perf_close() using
5074 if (event->hw.target)
5075 put_task_struct(event->hw.target);
5078 * perf_event_free_task() relies on put_ctx() being 'last', in particular
5079 * all task references must be cleaned up.
5082 put_ctx(event->ctx);
5084 exclusive_event_destroy(event);
5085 module_put(event->pmu->module);
5087 call_rcu(&event->rcu_head, free_event_rcu);
5091 * Used to free events which have a known refcount of 1, such as in error paths
5092 * where the event isn't exposed yet and inherited events.
5094 static void free_event(struct perf_event *event)
5096 if (WARN(atomic_long_cmpxchg(&event->refcount, 1, 0) != 1,
5097 "unexpected event refcount: %ld; ptr=%p\n",
5098 atomic_long_read(&event->refcount), event)) {
5099 /* leak to avoid use-after-free */
5107 * Remove user event from the owner task.
5109 static void perf_remove_from_owner(struct perf_event *event)
5111 struct task_struct *owner;
5115 * Matches the smp_store_release() in perf_event_exit_task(). If we
5116 * observe !owner it means the list deletion is complete and we can
5117 * indeed free this event, otherwise we need to serialize on
5118 * owner->perf_event_mutex.
5120 owner = READ_ONCE(event->owner);
5123 * Since delayed_put_task_struct() also drops the last
5124 * task reference we can safely take a new reference
5125 * while holding the rcu_read_lock().
5127 get_task_struct(owner);
5133 * If we're here through perf_event_exit_task() we're already
5134 * holding ctx->mutex which would be an inversion wrt. the
5135 * normal lock order.
5137 * However we can safely take this lock because its the child
5140 mutex_lock_nested(&owner->perf_event_mutex, SINGLE_DEPTH_NESTING);
5143 * We have to re-check the event->owner field, if it is cleared
5144 * we raced with perf_event_exit_task(), acquiring the mutex
5145 * ensured they're done, and we can proceed with freeing the
5149 list_del_init(&event->owner_entry);
5150 smp_store_release(&event->owner, NULL);
5152 mutex_unlock(&owner->perf_event_mutex);
5153 put_task_struct(owner);
5157 static void put_event(struct perf_event *event)
5159 if (!atomic_long_dec_and_test(&event->refcount))
5166 * Kill an event dead; while event:refcount will preserve the event
5167 * object, it will not preserve its functionality. Once the last 'user'
5168 * gives up the object, we'll destroy the thing.
5170 int perf_event_release_kernel(struct perf_event *event)
5172 struct perf_event_context *ctx = event->ctx;
5173 struct perf_event *child, *tmp;
5174 LIST_HEAD(free_list);
5177 * If we got here through err_file: fput(event_file); we will not have
5178 * attached to a context yet.
5181 WARN_ON_ONCE(event->attach_state &
5182 (PERF_ATTACH_CONTEXT|PERF_ATTACH_GROUP));
5186 if (!is_kernel_event(event))
5187 perf_remove_from_owner(event);
5189 ctx = perf_event_ctx_lock(event);
5190 WARN_ON_ONCE(ctx->parent_ctx);
5191 perf_remove_from_context(event, DETACH_GROUP);
5193 raw_spin_lock_irq(&ctx->lock);
5195 * Mark this event as STATE_DEAD, there is no external reference to it
5198 * Anybody acquiring event->child_mutex after the below loop _must_
5199 * also see this, most importantly inherit_event() which will avoid
5200 * placing more children on the list.
5202 * Thus this guarantees that we will in fact observe and kill _ALL_
5205 event->state = PERF_EVENT_STATE_DEAD;
5206 raw_spin_unlock_irq(&ctx->lock);
5208 perf_event_ctx_unlock(event, ctx);
5211 mutex_lock(&event->child_mutex);
5212 list_for_each_entry(child, &event->child_list, child_list) {
5215 * Cannot change, child events are not migrated, see the
5216 * comment with perf_event_ctx_lock_nested().
5218 ctx = READ_ONCE(child->ctx);
5220 * Since child_mutex nests inside ctx::mutex, we must jump
5221 * through hoops. We start by grabbing a reference on the ctx.
5223 * Since the event cannot get freed while we hold the
5224 * child_mutex, the context must also exist and have a !0
5230 * Now that we have a ctx ref, we can drop child_mutex, and
5231 * acquire ctx::mutex without fear of it going away. Then we
5232 * can re-acquire child_mutex.
5234 mutex_unlock(&event->child_mutex);
5235 mutex_lock(&ctx->mutex);
5236 mutex_lock(&event->child_mutex);
5239 * Now that we hold ctx::mutex and child_mutex, revalidate our
5240 * state, if child is still the first entry, it didn't get freed
5241 * and we can continue doing so.
5243 tmp = list_first_entry_or_null(&event->child_list,
5244 struct perf_event, child_list);
5246 perf_remove_from_context(child, DETACH_GROUP);
5247 list_move(&child->child_list, &free_list);
5249 * This matches the refcount bump in inherit_event();
5250 * this can't be the last reference.
5255 mutex_unlock(&event->child_mutex);
5256 mutex_unlock(&ctx->mutex);
5260 mutex_unlock(&event->child_mutex);
5262 list_for_each_entry_safe(child, tmp, &free_list, child_list) {
5263 void *var = &child->ctx->refcount;
5265 list_del(&child->child_list);
5269 * Wake any perf_event_free_task() waiting for this event to be
5272 smp_mb(); /* pairs with wait_var_event() */
5277 put_event(event); /* Must be the 'last' reference */
5280 EXPORT_SYMBOL_GPL(perf_event_release_kernel);
5283 * Called when the last reference to the file is gone.
5285 static int perf_release(struct inode *inode, struct file *file)
5287 perf_event_release_kernel(file->private_data);
5291 static u64 __perf_event_read_value(struct perf_event *event, u64 *enabled, u64 *running)
5293 struct perf_event *child;
5299 mutex_lock(&event->child_mutex);
5301 (void)perf_event_read(event, false);
5302 total += perf_event_count(event);
5304 *enabled += event->total_time_enabled +
5305 atomic64_read(&event->child_total_time_enabled);
5306 *running += event->total_time_running +
5307 atomic64_read(&event->child_total_time_running);
5309 list_for_each_entry(child, &event->child_list, child_list) {
5310 (void)perf_event_read(child, false);
5311 total += perf_event_count(child);
5312 *enabled += child->total_time_enabled;
5313 *running += child->total_time_running;
5315 mutex_unlock(&event->child_mutex);
5320 u64 perf_event_read_value(struct perf_event *event, u64 *enabled, u64 *running)
5322 struct perf_event_context *ctx;
5325 ctx = perf_event_ctx_lock(event);
5326 count = __perf_event_read_value(event, enabled, running);
5327 perf_event_ctx_unlock(event, ctx);
5331 EXPORT_SYMBOL_GPL(perf_event_read_value);
5333 static int __perf_read_group_add(struct perf_event *leader,
5334 u64 read_format, u64 *values)
5336 struct perf_event_context *ctx = leader->ctx;
5337 struct perf_event *sub;
5338 unsigned long flags;
5339 int n = 1; /* skip @nr */
5342 ret = perf_event_read(leader, true);
5346 raw_spin_lock_irqsave(&ctx->lock, flags);
5349 * Since we co-schedule groups, {enabled,running} times of siblings
5350 * will be identical to those of the leader, so we only publish one
5353 if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED) {
5354 values[n++] += leader->total_time_enabled +
5355 atomic64_read(&leader->child_total_time_enabled);
5358 if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING) {
5359 values[n++] += leader->total_time_running +
5360 atomic64_read(&leader->child_total_time_running);
5364 * Write {count,id} tuples for every sibling.
5366 values[n++] += perf_event_count(leader);
5367 if (read_format & PERF_FORMAT_ID)
5368 values[n++] = primary_event_id(leader);
5370 for_each_sibling_event(sub, leader) {
5371 values[n++] += perf_event_count(sub);
5372 if (read_format & PERF_FORMAT_ID)
5373 values[n++] = primary_event_id(sub);
5376 raw_spin_unlock_irqrestore(&ctx->lock, flags);
5380 static int perf_read_group(struct perf_event *event,
5381 u64 read_format, char __user *buf)
5383 struct perf_event *leader = event->group_leader, *child;
5384 struct perf_event_context *ctx = leader->ctx;
5388 lockdep_assert_held(&ctx->mutex);
5390 values = kzalloc(event->read_size, GFP_KERNEL);
5394 values[0] = 1 + leader->nr_siblings;
5397 * By locking the child_mutex of the leader we effectively
5398 * lock the child list of all siblings.. XXX explain how.
5400 mutex_lock(&leader->child_mutex);
5402 ret = __perf_read_group_add(leader, read_format, values);
5406 list_for_each_entry(child, &leader->child_list, child_list) {
5407 ret = __perf_read_group_add(child, read_format, values);
5412 mutex_unlock(&leader->child_mutex);
5414 ret = event->read_size;
5415 if (copy_to_user(buf, values, event->read_size))
5420 mutex_unlock(&leader->child_mutex);
5426 static int perf_read_one(struct perf_event *event,
5427 u64 read_format, char __user *buf)
5429 u64 enabled, running;
5433 values[n++] = __perf_event_read_value(event, &enabled, &running);
5434 if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED)
5435 values[n++] = enabled;
5436 if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING)
5437 values[n++] = running;
5438 if (read_format & PERF_FORMAT_ID)
5439 values[n++] = primary_event_id(event);
5441 if (copy_to_user(buf, values, n * sizeof(u64)))
5444 return n * sizeof(u64);
5447 static bool is_event_hup(struct perf_event *event)
5451 if (event->state > PERF_EVENT_STATE_EXIT)
5454 mutex_lock(&event->child_mutex);
5455 no_children = list_empty(&event->child_list);
5456 mutex_unlock(&event->child_mutex);
5461 * Read the performance event - simple non blocking version for now
5464 __perf_read(struct perf_event *event, char __user *buf, size_t count)
5466 u64 read_format = event->attr.read_format;
5470 * Return end-of-file for a read on an event that is in
5471 * error state (i.e. because it was pinned but it couldn't be
5472 * scheduled on to the CPU at some point).
5474 if (event->state == PERF_EVENT_STATE_ERROR)
5477 if (count < event->read_size)
5480 WARN_ON_ONCE(event->ctx->parent_ctx);
5481 if (read_format & PERF_FORMAT_GROUP)
5482 ret = perf_read_group(event, read_format, buf);
5484 ret = perf_read_one(event, read_format, buf);
5490 perf_read(struct file *file, char __user *buf, size_t count, loff_t *ppos)
5492 struct perf_event *event = file->private_data;
5493 struct perf_event_context *ctx;
5496 ret = security_perf_event_read(event);
5500 ctx = perf_event_ctx_lock(event);
5501 ret = __perf_read(event, buf, count);
5502 perf_event_ctx_unlock(event, ctx);
5507 static __poll_t perf_poll(struct file *file, poll_table *wait)
5509 struct perf_event *event = file->private_data;
5510 struct perf_buffer *rb;
5511 __poll_t events = EPOLLHUP;
5513 poll_wait(file, &event->waitq, wait);
5515 if (is_event_hup(event))
5519 * Pin the event->rb by taking event->mmap_mutex; otherwise
5520 * perf_event_set_output() can swizzle our rb and make us miss wakeups.
5522 mutex_lock(&event->mmap_mutex);
5525 events = atomic_xchg(&rb->poll, 0);
5526 mutex_unlock(&event->mmap_mutex);
5530 static void _perf_event_reset(struct perf_event *event)
5532 (void)perf_event_read(event, false);
5533 local64_set(&event->count, 0);
5534 perf_event_update_userpage(event);
5537 /* Assume it's not an event with inherit set. */
5538 u64 perf_event_pause(struct perf_event *event, bool reset)
5540 struct perf_event_context *ctx;
5543 ctx = perf_event_ctx_lock(event);
5544 WARN_ON_ONCE(event->attr.inherit);
5545 _perf_event_disable(event);
5546 count = local64_read(&event->count);
5548 local64_set(&event->count, 0);
5549 perf_event_ctx_unlock(event, ctx);
5553 EXPORT_SYMBOL_GPL(perf_event_pause);
5556 * Holding the top-level event's child_mutex means that any
5557 * descendant process that has inherited this event will block
5558 * in perf_event_exit_event() if it goes to exit, thus satisfying the
5559 * task existence requirements of perf_event_enable/disable.
5561 static void perf_event_for_each_child(struct perf_event *event,
5562 void (*func)(struct perf_event *))
5564 struct perf_event *child;
5566 WARN_ON_ONCE(event->ctx->parent_ctx);
5568 mutex_lock(&event->child_mutex);
5570 list_for_each_entry(child, &event->child_list, child_list)
5572 mutex_unlock(&event->child_mutex);
5575 static void perf_event_for_each(struct perf_event *event,
5576 void (*func)(struct perf_event *))
5578 struct perf_event_context *ctx = event->ctx;
5579 struct perf_event *sibling;
5581 lockdep_assert_held(&ctx->mutex);
5583 event = event->group_leader;
5585 perf_event_for_each_child(event, func);
5586 for_each_sibling_event(sibling, event)
5587 perf_event_for_each_child(sibling, func);
5590 static void __perf_event_period(struct perf_event *event,
5591 struct perf_cpu_context *cpuctx,
5592 struct perf_event_context *ctx,
5595 u64 value = *((u64 *)info);
5598 if (event->attr.freq) {
5599 event->attr.sample_freq = value;
5601 event->attr.sample_period = value;
5602 event->hw.sample_period = value;
5605 active = (event->state == PERF_EVENT_STATE_ACTIVE);
5607 perf_pmu_disable(ctx->pmu);
5609 * We could be throttled; unthrottle now to avoid the tick
5610 * trying to unthrottle while we already re-started the event.
5612 if (event->hw.interrupts == MAX_INTERRUPTS) {
5613 event->hw.interrupts = 0;
5614 perf_log_throttle(event, 1);
5616 event->pmu->stop(event, PERF_EF_UPDATE);
5619 local64_set(&event->hw.period_left, 0);
5622 event->pmu->start(event, PERF_EF_RELOAD);
5623 perf_pmu_enable(ctx->pmu);
5627 static int perf_event_check_period(struct perf_event *event, u64 value)
5629 return event->pmu->check_period(event, value);
5632 static int _perf_event_period(struct perf_event *event, u64 value)
5634 if (!is_sampling_event(event))
5640 if (event->attr.freq && value > sysctl_perf_event_sample_rate)
5643 if (perf_event_check_period(event, value))
5646 if (!event->attr.freq && (value & (1ULL << 63)))
5649 event_function_call(event, __perf_event_period, &value);
5654 int perf_event_period(struct perf_event *event, u64 value)
5656 struct perf_event_context *ctx;
5659 ctx = perf_event_ctx_lock(event);
5660 ret = _perf_event_period(event, value);
5661 perf_event_ctx_unlock(event, ctx);
5665 EXPORT_SYMBOL_GPL(perf_event_period);
5667 static const struct file_operations perf_fops;
5669 static inline int perf_fget_light(int fd, struct fd *p)
5671 struct fd f = fdget(fd);
5675 if (f.file->f_op != &perf_fops) {
5683 static int perf_event_set_output(struct perf_event *event,
5684 struct perf_event *output_event);
5685 static int perf_event_set_filter(struct perf_event *event, void __user *arg);
5686 static int perf_copy_attr(struct perf_event_attr __user *uattr,
5687 struct perf_event_attr *attr);
5689 static long _perf_ioctl(struct perf_event *event, unsigned int cmd, unsigned long arg)
5691 void (*func)(struct perf_event *);
5695 case PERF_EVENT_IOC_ENABLE:
5696 func = _perf_event_enable;
5698 case PERF_EVENT_IOC_DISABLE:
5699 func = _perf_event_disable;
5701 case PERF_EVENT_IOC_RESET:
5702 func = _perf_event_reset;
5705 case PERF_EVENT_IOC_REFRESH:
5706 return _perf_event_refresh(event, arg);
5708 case PERF_EVENT_IOC_PERIOD:
5712 if (copy_from_user(&value, (u64 __user *)arg, sizeof(value)))
5715 return _perf_event_period(event, value);
5717 case PERF_EVENT_IOC_ID:
5719 u64 id = primary_event_id(event);
5721 if (copy_to_user((void __user *)arg, &id, sizeof(id)))
5726 case PERF_EVENT_IOC_SET_OUTPUT:
5730 struct perf_event *output_event;
5732 ret = perf_fget_light(arg, &output);
5735 output_event = output.file->private_data;
5736 ret = perf_event_set_output(event, output_event);
5739 ret = perf_event_set_output(event, NULL);
5744 case PERF_EVENT_IOC_SET_FILTER:
5745 return perf_event_set_filter(event, (void __user *)arg);
5747 case PERF_EVENT_IOC_SET_BPF:
5749 struct bpf_prog *prog;
5752 prog = bpf_prog_get(arg);
5754 return PTR_ERR(prog);
5756 err = perf_event_set_bpf_prog(event, prog, 0);
5765 case PERF_EVENT_IOC_PAUSE_OUTPUT: {
5766 struct perf_buffer *rb;
5769 rb = rcu_dereference(event->rb);
5770 if (!rb || !rb->nr_pages) {
5774 rb_toggle_paused(rb, !!arg);
5779 case PERF_EVENT_IOC_QUERY_BPF:
5780 return perf_event_query_prog_array(event, (void __user *)arg);
5782 case PERF_EVENT_IOC_MODIFY_ATTRIBUTES: {
5783 struct perf_event_attr new_attr;
5784 int err = perf_copy_attr((struct perf_event_attr __user *)arg,
5790 return perf_event_modify_attr(event, &new_attr);
5796 if (flags & PERF_IOC_FLAG_GROUP)
5797 perf_event_for_each(event, func);
5799 perf_event_for_each_child(event, func);
5804 static long perf_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
5806 struct perf_event *event = file->private_data;
5807 struct perf_event_context *ctx;
5810 /* Treat ioctl like writes as it is likely a mutating operation. */
5811 ret = security_perf_event_write(event);
5815 ctx = perf_event_ctx_lock(event);
5816 ret = _perf_ioctl(event, cmd, arg);
5817 perf_event_ctx_unlock(event, ctx);
5822 #ifdef CONFIG_COMPAT
5823 static long perf_compat_ioctl(struct file *file, unsigned int cmd,
5826 switch (_IOC_NR(cmd)) {
5827 case _IOC_NR(PERF_EVENT_IOC_SET_FILTER):
5828 case _IOC_NR(PERF_EVENT_IOC_ID):
5829 case _IOC_NR(PERF_EVENT_IOC_QUERY_BPF):
5830 case _IOC_NR(PERF_EVENT_IOC_MODIFY_ATTRIBUTES):
5831 /* Fix up pointer size (usually 4 -> 8 in 32-on-64-bit case */
5832 if (_IOC_SIZE(cmd) == sizeof(compat_uptr_t)) {
5833 cmd &= ~IOCSIZE_MASK;
5834 cmd |= sizeof(void *) << IOCSIZE_SHIFT;
5838 return perf_ioctl(file, cmd, arg);
5841 # define perf_compat_ioctl NULL
5844 int perf_event_task_enable(void)
5846 struct perf_event_context *ctx;
5847 struct perf_event *event;
5849 mutex_lock(¤t->perf_event_mutex);
5850 list_for_each_entry(event, ¤t->perf_event_list, owner_entry) {
5851 ctx = perf_event_ctx_lock(event);
5852 perf_event_for_each_child(event, _perf_event_enable);
5853 perf_event_ctx_unlock(event, ctx);
5855 mutex_unlock(¤t->perf_event_mutex);
5860 int perf_event_task_disable(void)
5862 struct perf_event_context *ctx;
5863 struct perf_event *event;
5865 mutex_lock(¤t->perf_event_mutex);
5866 list_for_each_entry(event, ¤t->perf_event_list, owner_entry) {
5867 ctx = perf_event_ctx_lock(event);
5868 perf_event_for_each_child(event, _perf_event_disable);
5869 perf_event_ctx_unlock(event, ctx);
5871 mutex_unlock(¤t->perf_event_mutex);
5876 static int perf_event_index(struct perf_event *event)
5878 if (event->hw.state & PERF_HES_STOPPED)
5881 if (event->state != PERF_EVENT_STATE_ACTIVE)
5884 return event->pmu->event_idx(event);
5887 static void perf_event_init_userpage(struct perf_event *event)
5889 struct perf_event_mmap_page *userpg;
5890 struct perf_buffer *rb;
5893 rb = rcu_dereference(event->rb);
5897 userpg = rb->user_page;
5899 /* Allow new userspace to detect that bit 0 is deprecated */
5900 userpg->cap_bit0_is_deprecated = 1;
5901 userpg->size = offsetof(struct perf_event_mmap_page, __reserved);
5902 userpg->data_offset = PAGE_SIZE;
5903 userpg->data_size = perf_data_size(rb);
5909 void __weak arch_perf_update_userpage(
5910 struct perf_event *event, struct perf_event_mmap_page *userpg, u64 now)
5915 * Callers need to ensure there can be no nesting of this function, otherwise
5916 * the seqlock logic goes bad. We can not serialize this because the arch
5917 * code calls this from NMI context.
5919 void perf_event_update_userpage(struct perf_event *event)
5921 struct perf_event_mmap_page *userpg;
5922 struct perf_buffer *rb;
5923 u64 enabled, running, now;
5926 rb = rcu_dereference(event->rb);
5931 * compute total_time_enabled, total_time_running
5932 * based on snapshot values taken when the event
5933 * was last scheduled in.
5935 * we cannot simply called update_context_time()
5936 * because of locking issue as we can be called in
5939 calc_timer_values(event, &now, &enabled, &running);
5941 userpg = rb->user_page;
5943 * Disable preemption to guarantee consistent time stamps are stored to
5949 userpg->index = perf_event_index(event);
5950 userpg->offset = perf_event_count(event);
5952 userpg->offset -= local64_read(&event->hw.prev_count);
5954 userpg->time_enabled = enabled +
5955 atomic64_read(&event->child_total_time_enabled);
5957 userpg->time_running = running +
5958 atomic64_read(&event->child_total_time_running);
5960 arch_perf_update_userpage(event, userpg, now);
5968 EXPORT_SYMBOL_GPL(perf_event_update_userpage);
5970 static vm_fault_t perf_mmap_fault(struct vm_fault *vmf)
5972 struct perf_event *event = vmf->vma->vm_file->private_data;
5973 struct perf_buffer *rb;
5974 vm_fault_t ret = VM_FAULT_SIGBUS;
5976 if (vmf->flags & FAULT_FLAG_MKWRITE) {
5977 if (vmf->pgoff == 0)
5983 rb = rcu_dereference(event->rb);
5987 if (vmf->pgoff && (vmf->flags & FAULT_FLAG_WRITE))
5990 vmf->page = perf_mmap_to_page(rb, vmf->pgoff);
5994 get_page(vmf->page);
5995 vmf->page->mapping = vmf->vma->vm_file->f_mapping;
5996 vmf->page->index = vmf->pgoff;
6005 static void ring_buffer_attach(struct perf_event *event,
6006 struct perf_buffer *rb)
6008 struct perf_buffer *old_rb = NULL;
6009 unsigned long flags;
6011 WARN_ON_ONCE(event->parent);
6015 * Should be impossible, we set this when removing
6016 * event->rb_entry and wait/clear when adding event->rb_entry.
6018 WARN_ON_ONCE(event->rcu_pending);
6021 spin_lock_irqsave(&old_rb->event_lock, flags);
6022 list_del_rcu(&event->rb_entry);
6023 spin_unlock_irqrestore(&old_rb->event_lock, flags);
6025 event->rcu_batches = get_state_synchronize_rcu();
6026 event->rcu_pending = 1;
6030 if (event->rcu_pending) {
6031 cond_synchronize_rcu(event->rcu_batches);
6032 event->rcu_pending = 0;
6035 spin_lock_irqsave(&rb->event_lock, flags);
6036 list_add_rcu(&event->rb_entry, &rb->event_list);
6037 spin_unlock_irqrestore(&rb->event_lock, flags);
6041 * Avoid racing with perf_mmap_close(AUX): stop the event
6042 * before swizzling the event::rb pointer; if it's getting
6043 * unmapped, its aux_mmap_count will be 0 and it won't
6044 * restart. See the comment in __perf_pmu_output_stop().
6046 * Data will inevitably be lost when set_output is done in
6047 * mid-air, but then again, whoever does it like this is
6048 * not in for the data anyway.
6051 perf_event_stop(event, 0);
6053 rcu_assign_pointer(event->rb, rb);
6056 ring_buffer_put(old_rb);
6058 * Since we detached before setting the new rb, so that we
6059 * could attach the new rb, we could have missed a wakeup.
6062 wake_up_all(&event->waitq);
6066 static void ring_buffer_wakeup(struct perf_event *event)
6068 struct perf_buffer *rb;
6071 event = event->parent;
6074 rb = rcu_dereference(event->rb);
6076 list_for_each_entry_rcu(event, &rb->event_list, rb_entry)
6077 wake_up_all(&event->waitq);
6082 struct perf_buffer *ring_buffer_get(struct perf_event *event)
6084 struct perf_buffer *rb;
6087 event = event->parent;
6090 rb = rcu_dereference(event->rb);
6092 if (!refcount_inc_not_zero(&rb->refcount))
6100 void ring_buffer_put(struct perf_buffer *rb)
6102 if (!refcount_dec_and_test(&rb->refcount))
6105 WARN_ON_ONCE(!list_empty(&rb->event_list));
6107 call_rcu(&rb->rcu_head, rb_free_rcu);
6110 static void perf_mmap_open(struct vm_area_struct *vma)
6112 struct perf_event *event = vma->vm_file->private_data;
6114 atomic_inc(&event->mmap_count);
6115 atomic_inc(&event->rb->mmap_count);
6118 atomic_inc(&event->rb->aux_mmap_count);
6120 if (event->pmu->event_mapped)
6121 event->pmu->event_mapped(event, vma->vm_mm);
6124 static void perf_pmu_output_stop(struct perf_event *event);
6127 * A buffer can be mmap()ed multiple times; either directly through the same
6128 * event, or through other events by use of perf_event_set_output().
6130 * In order to undo the VM accounting done by perf_mmap() we need to destroy
6131 * the buffer here, where we still have a VM context. This means we need
6132 * to detach all events redirecting to us.
6134 static void perf_mmap_close(struct vm_area_struct *vma)
6136 struct perf_event *event = vma->vm_file->private_data;
6137 struct perf_buffer *rb = ring_buffer_get(event);
6138 struct user_struct *mmap_user = rb->mmap_user;
6139 int mmap_locked = rb->mmap_locked;
6140 unsigned long size = perf_data_size(rb);
6141 bool detach_rest = false;
6143 if (event->pmu->event_unmapped)
6144 event->pmu->event_unmapped(event, vma->vm_mm);
6147 * rb->aux_mmap_count will always drop before rb->mmap_count and
6148 * event->mmap_count, so it is ok to use event->mmap_mutex to
6149 * serialize with perf_mmap here.
6151 if (rb_has_aux(rb) && vma->vm_pgoff == rb->aux_pgoff &&
6152 atomic_dec_and_mutex_lock(&rb->aux_mmap_count, &event->mmap_mutex)) {
6154 * Stop all AUX events that are writing to this buffer,
6155 * so that we can free its AUX pages and corresponding PMU
6156 * data. Note that after rb::aux_mmap_count dropped to zero,
6157 * they won't start any more (see perf_aux_output_begin()).
6159 perf_pmu_output_stop(event);
6161 /* now it's safe to free the pages */
6162 atomic_long_sub(rb->aux_nr_pages - rb->aux_mmap_locked, &mmap_user->locked_vm);
6163 atomic64_sub(rb->aux_mmap_locked, &vma->vm_mm->pinned_vm);
6165 /* this has to be the last one */
6167 WARN_ON_ONCE(refcount_read(&rb->aux_refcount));
6169 mutex_unlock(&event->mmap_mutex);
6172 if (atomic_dec_and_test(&rb->mmap_count))
6175 if (!atomic_dec_and_mutex_lock(&event->mmap_count, &event->mmap_mutex))
6178 ring_buffer_attach(event, NULL);
6179 mutex_unlock(&event->mmap_mutex);
6181 /* If there's still other mmap()s of this buffer, we're done. */
6186 * No other mmap()s, detach from all other events that might redirect
6187 * into the now unreachable buffer. Somewhat complicated by the
6188 * fact that rb::event_lock otherwise nests inside mmap_mutex.
6192 list_for_each_entry_rcu(event, &rb->event_list, rb_entry) {
6193 if (!atomic_long_inc_not_zero(&event->refcount)) {
6195 * This event is en-route to free_event() which will
6196 * detach it and remove it from the list.
6202 mutex_lock(&event->mmap_mutex);
6204 * Check we didn't race with perf_event_set_output() which can
6205 * swizzle the rb from under us while we were waiting to
6206 * acquire mmap_mutex.
6208 * If we find a different rb; ignore this event, a next
6209 * iteration will no longer find it on the list. We have to
6210 * still restart the iteration to make sure we're not now
6211 * iterating the wrong list.
6213 if (event->rb == rb)
6214 ring_buffer_attach(event, NULL);
6216 mutex_unlock(&event->mmap_mutex);
6220 * Restart the iteration; either we're on the wrong list or
6221 * destroyed its integrity by doing a deletion.
6228 * It could be there's still a few 0-ref events on the list; they'll
6229 * get cleaned up by free_event() -- they'll also still have their
6230 * ref on the rb and will free it whenever they are done with it.
6232 * Aside from that, this buffer is 'fully' detached and unmapped,
6233 * undo the VM accounting.
6236 atomic_long_sub((size >> PAGE_SHIFT) + 1 - mmap_locked,
6237 &mmap_user->locked_vm);
6238 atomic64_sub(mmap_locked, &vma->vm_mm->pinned_vm);
6239 free_uid(mmap_user);
6242 ring_buffer_put(rb); /* could be last */
6245 static const struct vm_operations_struct perf_mmap_vmops = {
6246 .open = perf_mmap_open,
6247 .close = perf_mmap_close, /* non mergeable */
6248 .fault = perf_mmap_fault,
6249 .page_mkwrite = perf_mmap_fault,
6252 static int perf_mmap(struct file *file, struct vm_area_struct *vma)
6254 struct perf_event *event = file->private_data;
6255 unsigned long user_locked, user_lock_limit;
6256 struct user_struct *user = current_user();
6257 struct perf_buffer *rb = NULL;
6258 unsigned long locked, lock_limit;
6259 unsigned long vma_size;
6260 unsigned long nr_pages;
6261 long user_extra = 0, extra = 0;
6262 int ret = 0, flags = 0;
6265 * Don't allow mmap() of inherited per-task counters. This would
6266 * create a performance issue due to all children writing to the
6269 if (event->cpu == -1 && event->attr.inherit)
6272 if (!(vma->vm_flags & VM_SHARED))
6275 ret = security_perf_event_read(event);
6279 vma_size = vma->vm_end - vma->vm_start;
6281 if (vma->vm_pgoff == 0) {
6282 nr_pages = (vma_size / PAGE_SIZE) - 1;
6285 * AUX area mapping: if rb->aux_nr_pages != 0, it's already
6286 * mapped, all subsequent mappings should have the same size
6287 * and offset. Must be above the normal perf buffer.
6289 u64 aux_offset, aux_size;
6294 nr_pages = vma_size / PAGE_SIZE;
6296 mutex_lock(&event->mmap_mutex);
6303 aux_offset = READ_ONCE(rb->user_page->aux_offset);
6304 aux_size = READ_ONCE(rb->user_page->aux_size);
6306 if (aux_offset < perf_data_size(rb) + PAGE_SIZE)
6309 if (aux_offset != vma->vm_pgoff << PAGE_SHIFT)
6312 /* already mapped with a different offset */
6313 if (rb_has_aux(rb) && rb->aux_pgoff != vma->vm_pgoff)
6316 if (aux_size != vma_size || aux_size != nr_pages * PAGE_SIZE)
6319 /* already mapped with a different size */
6320 if (rb_has_aux(rb) && rb->aux_nr_pages != nr_pages)
6323 if (!is_power_of_2(nr_pages))
6326 if (!atomic_inc_not_zero(&rb->mmap_count))
6329 if (rb_has_aux(rb)) {
6330 atomic_inc(&rb->aux_mmap_count);
6335 atomic_set(&rb->aux_mmap_count, 1);
6336 user_extra = nr_pages;
6342 * If we have rb pages ensure they're a power-of-two number, so we
6343 * can do bitmasks instead of modulo.
6345 if (nr_pages != 0 && !is_power_of_2(nr_pages))
6348 if (vma_size != PAGE_SIZE * (1 + nr_pages))
6351 WARN_ON_ONCE(event->ctx->parent_ctx);
6353 mutex_lock(&event->mmap_mutex);
6355 if (event->rb->nr_pages != nr_pages) {
6360 if (!atomic_inc_not_zero(&event->rb->mmap_count)) {
6362 * Raced against perf_mmap_close() through
6363 * perf_event_set_output(). Try again, hope for better
6366 mutex_unlock(&event->mmap_mutex);
6373 user_extra = nr_pages + 1;
6376 user_lock_limit = sysctl_perf_event_mlock >> (PAGE_SHIFT - 10);
6379 * Increase the limit linearly with more CPUs:
6381 user_lock_limit *= num_online_cpus();
6383 user_locked = atomic_long_read(&user->locked_vm);
6386 * sysctl_perf_event_mlock may have changed, so that
6387 * user->locked_vm > user_lock_limit
6389 if (user_locked > user_lock_limit)
6390 user_locked = user_lock_limit;
6391 user_locked += user_extra;
6393 if (user_locked > user_lock_limit) {
6395 * charge locked_vm until it hits user_lock_limit;
6396 * charge the rest from pinned_vm
6398 extra = user_locked - user_lock_limit;
6399 user_extra -= extra;
6402 lock_limit = rlimit(RLIMIT_MEMLOCK);
6403 lock_limit >>= PAGE_SHIFT;
6404 locked = atomic64_read(&vma->vm_mm->pinned_vm) + extra;
6406 if ((locked > lock_limit) && perf_is_paranoid() &&
6407 !capable(CAP_IPC_LOCK)) {
6412 WARN_ON(!rb && event->rb);
6414 if (vma->vm_flags & VM_WRITE)
6415 flags |= RING_BUFFER_WRITABLE;
6418 rb = rb_alloc(nr_pages,
6419 event->attr.watermark ? event->attr.wakeup_watermark : 0,
6427 atomic_set(&rb->mmap_count, 1);
6428 rb->mmap_user = get_current_user();
6429 rb->mmap_locked = extra;
6431 ring_buffer_attach(event, rb);
6433 perf_event_update_time(event);
6434 perf_event_init_userpage(event);
6435 perf_event_update_userpage(event);
6437 ret = rb_alloc_aux(rb, event, vma->vm_pgoff, nr_pages,
6438 event->attr.aux_watermark, flags);
6440 rb->aux_mmap_locked = extra;
6445 atomic_long_add(user_extra, &user->locked_vm);
6446 atomic64_add(extra, &vma->vm_mm->pinned_vm);
6448 atomic_inc(&event->mmap_count);
6450 atomic_dec(&rb->mmap_count);
6453 mutex_unlock(&event->mmap_mutex);
6456 * Since pinned accounting is per vm we cannot allow fork() to copy our
6459 vma->vm_flags |= VM_DONTCOPY | VM_DONTEXPAND | VM_DONTDUMP;
6460 vma->vm_ops = &perf_mmap_vmops;
6462 if (event->pmu->event_mapped)
6463 event->pmu->event_mapped(event, vma->vm_mm);
6468 static int perf_fasync(int fd, struct file *filp, int on)
6470 struct inode *inode = file_inode(filp);
6471 struct perf_event *event = filp->private_data;
6475 retval = fasync_helper(fd, filp, on, &event->fasync);
6476 inode_unlock(inode);
6484 static const struct file_operations perf_fops = {
6485 .llseek = no_llseek,
6486 .release = perf_release,
6489 .unlocked_ioctl = perf_ioctl,
6490 .compat_ioctl = perf_compat_ioctl,
6492 .fasync = perf_fasync,
6498 * If there's data, ensure we set the poll() state and publish everything
6499 * to user-space before waking everybody up.
6502 static inline struct fasync_struct **perf_event_fasync(struct perf_event *event)
6504 /* only the parent has fasync state */
6506 event = event->parent;
6507 return &event->fasync;
6510 void perf_event_wakeup(struct perf_event *event)
6512 ring_buffer_wakeup(event);
6514 if (event->pending_kill) {
6515 kill_fasync(perf_event_fasync(event), SIGIO, event->pending_kill);
6516 event->pending_kill = 0;
6520 static void perf_sigtrap(struct perf_event *event)
6523 * We'd expect this to only occur if the irq_work is delayed and either
6524 * ctx->task or current has changed in the meantime. This can be the
6525 * case on architectures that do not implement arch_irq_work_raise().
6527 if (WARN_ON_ONCE(event->ctx->task != current))
6531 * perf_pending_event() can race with the task exiting.
6533 if (current->flags & PF_EXITING)
6536 force_sig_perf((void __user *)event->pending_addr,
6537 event->attr.type, event->attr.sig_data);
6540 static void perf_pending_event_disable(struct perf_event *event)
6542 int cpu = READ_ONCE(event->pending_disable);
6547 if (cpu == smp_processor_id()) {
6548 WRITE_ONCE(event->pending_disable, -1);
6550 if (event->attr.sigtrap) {
6551 perf_sigtrap(event);
6552 atomic_set_release(&event->event_limit, 1); /* rearm event */
6556 perf_event_disable_local(event);
6563 * perf_event_disable_inatomic()
6564 * @pending_disable = CPU-A;
6568 * @pending_disable = -1;
6571 * perf_event_disable_inatomic()
6572 * @pending_disable = CPU-B;
6573 * irq_work_queue(); // FAILS
6576 * perf_pending_event()
6578 * But the event runs on CPU-B and wants disabling there.
6580 irq_work_queue_on(&event->pending, cpu);
6583 static void perf_pending_event(struct irq_work *entry)
6585 struct perf_event *event = container_of(entry, struct perf_event, pending);
6588 rctx = perf_swevent_get_recursion_context();
6590 * If we 'fail' here, that's OK, it means recursion is already disabled
6591 * and we won't recurse 'further'.
6594 perf_pending_event_disable(event);
6596 if (event->pending_wakeup) {
6597 event->pending_wakeup = 0;
6598 perf_event_wakeup(event);
6602 perf_swevent_put_recursion_context(rctx);
6605 #ifdef CONFIG_GUEST_PERF_EVENTS
6606 struct perf_guest_info_callbacks __rcu *perf_guest_cbs;
6608 DEFINE_STATIC_CALL_RET0(__perf_guest_state, *perf_guest_cbs->state);
6609 DEFINE_STATIC_CALL_RET0(__perf_guest_get_ip, *perf_guest_cbs->get_ip);
6610 DEFINE_STATIC_CALL_RET0(__perf_guest_handle_intel_pt_intr, *perf_guest_cbs->handle_intel_pt_intr);
6612 void perf_register_guest_info_callbacks(struct perf_guest_info_callbacks *cbs)
6614 if (WARN_ON_ONCE(rcu_access_pointer(perf_guest_cbs)))
6617 rcu_assign_pointer(perf_guest_cbs, cbs);
6618 static_call_update(__perf_guest_state, cbs->state);
6619 static_call_update(__perf_guest_get_ip, cbs->get_ip);
6621 /* Implementing ->handle_intel_pt_intr is optional. */
6622 if (cbs->handle_intel_pt_intr)
6623 static_call_update(__perf_guest_handle_intel_pt_intr,
6624 cbs->handle_intel_pt_intr);
6626 EXPORT_SYMBOL_GPL(perf_register_guest_info_callbacks);
6628 void perf_unregister_guest_info_callbacks(struct perf_guest_info_callbacks *cbs)
6630 if (WARN_ON_ONCE(rcu_access_pointer(perf_guest_cbs) != cbs))
6633 rcu_assign_pointer(perf_guest_cbs, NULL);
6634 static_call_update(__perf_guest_state, (void *)&__static_call_return0);
6635 static_call_update(__perf_guest_get_ip, (void *)&__static_call_return0);
6636 static_call_update(__perf_guest_handle_intel_pt_intr,
6637 (void *)&__static_call_return0);
6640 EXPORT_SYMBOL_GPL(perf_unregister_guest_info_callbacks);
6644 perf_output_sample_regs(struct perf_output_handle *handle,
6645 struct pt_regs *regs, u64 mask)
6648 DECLARE_BITMAP(_mask, 64);
6650 bitmap_from_u64(_mask, mask);
6651 for_each_set_bit(bit, _mask, sizeof(mask) * BITS_PER_BYTE) {
6654 val = perf_reg_value(regs, bit);
6655 perf_output_put(handle, val);
6659 static void perf_sample_regs_user(struct perf_regs *regs_user,
6660 struct pt_regs *regs)
6662 if (user_mode(regs)) {
6663 regs_user->abi = perf_reg_abi(current);
6664 regs_user->regs = regs;
6665 } else if (!(current->flags & PF_KTHREAD)) {
6666 perf_get_regs_user(regs_user, regs);
6668 regs_user->abi = PERF_SAMPLE_REGS_ABI_NONE;
6669 regs_user->regs = NULL;
6673 static void perf_sample_regs_intr(struct perf_regs *regs_intr,
6674 struct pt_regs *regs)
6676 regs_intr->regs = regs;
6677 regs_intr->abi = perf_reg_abi(current);
6682 * Get remaining task size from user stack pointer.
6684 * It'd be better to take stack vma map and limit this more
6685 * precisely, but there's no way to get it safely under interrupt,
6686 * so using TASK_SIZE as limit.
6688 static u64 perf_ustack_task_size(struct pt_regs *regs)
6690 unsigned long addr = perf_user_stack_pointer(regs);
6692 if (!addr || addr >= TASK_SIZE)
6695 return TASK_SIZE - addr;
6699 perf_sample_ustack_size(u16 stack_size, u16 header_size,
6700 struct pt_regs *regs)
6704 /* No regs, no stack pointer, no dump. */
6709 * Check if we fit in with the requested stack size into the:
6711 * If we don't, we limit the size to the TASK_SIZE.
6713 * - remaining sample size
6714 * If we don't, we customize the stack size to
6715 * fit in to the remaining sample size.
6718 task_size = min((u64) USHRT_MAX, perf_ustack_task_size(regs));
6719 stack_size = min(stack_size, (u16) task_size);
6721 /* Current header size plus static size and dynamic size. */
6722 header_size += 2 * sizeof(u64);
6724 /* Do we fit in with the current stack dump size? */
6725 if ((u16) (header_size + stack_size) < header_size) {
6727 * If we overflow the maximum size for the sample,
6728 * we customize the stack dump size to fit in.
6730 stack_size = USHRT_MAX - header_size - sizeof(u64);
6731 stack_size = round_up(stack_size, sizeof(u64));
6738 perf_output_sample_ustack(struct perf_output_handle *handle, u64 dump_size,
6739 struct pt_regs *regs)
6741 /* Case of a kernel thread, nothing to dump */
6744 perf_output_put(handle, size);
6754 * - the size requested by user or the best one we can fit
6755 * in to the sample max size
6757 * - user stack dump data
6759 * - the actual dumped size
6763 perf_output_put(handle, dump_size);
6766 sp = perf_user_stack_pointer(regs);
6767 fs = force_uaccess_begin();
6768 rem = __output_copy_user(handle, (void *) sp, dump_size);
6769 force_uaccess_end(fs);
6770 dyn_size = dump_size - rem;
6772 perf_output_skip(handle, rem);
6775 perf_output_put(handle, dyn_size);
6779 static unsigned long perf_prepare_sample_aux(struct perf_event *event,
6780 struct perf_sample_data *data,
6783 struct perf_event *sampler = event->aux_event;
6784 struct perf_buffer *rb;
6791 if (WARN_ON_ONCE(READ_ONCE(sampler->state) != PERF_EVENT_STATE_ACTIVE))
6794 if (WARN_ON_ONCE(READ_ONCE(sampler->oncpu) != smp_processor_id()))
6797 rb = ring_buffer_get(sampler);
6802 * If this is an NMI hit inside sampling code, don't take
6803 * the sample. See also perf_aux_sample_output().
6805 if (READ_ONCE(rb->aux_in_sampling)) {
6808 size = min_t(size_t, size, perf_aux_size(rb));
6809 data->aux_size = ALIGN(size, sizeof(u64));
6811 ring_buffer_put(rb);
6814 return data->aux_size;
6817 static long perf_pmu_snapshot_aux(struct perf_buffer *rb,
6818 struct perf_event *event,
6819 struct perf_output_handle *handle,
6822 unsigned long flags;
6826 * Normal ->start()/->stop() callbacks run in IRQ mode in scheduler
6827 * paths. If we start calling them in NMI context, they may race with
6828 * the IRQ ones, that is, for example, re-starting an event that's just
6829 * been stopped, which is why we're using a separate callback that
6830 * doesn't change the event state.
6832 * IRQs need to be disabled to prevent IPIs from racing with us.
6834 local_irq_save(flags);
6836 * Guard against NMI hits inside the critical section;
6837 * see also perf_prepare_sample_aux().
6839 WRITE_ONCE(rb->aux_in_sampling, 1);
6842 ret = event->pmu->snapshot_aux(event, handle, size);
6845 WRITE_ONCE(rb->aux_in_sampling, 0);
6846 local_irq_restore(flags);
6851 static void perf_aux_sample_output(struct perf_event *event,
6852 struct perf_output_handle *handle,
6853 struct perf_sample_data *data)
6855 struct perf_event *sampler = event->aux_event;
6856 struct perf_buffer *rb;
6860 if (WARN_ON_ONCE(!sampler || !data->aux_size))
6863 rb = ring_buffer_get(sampler);
6867 size = perf_pmu_snapshot_aux(rb, sampler, handle, data->aux_size);
6870 * An error here means that perf_output_copy() failed (returned a
6871 * non-zero surplus that it didn't copy), which in its current
6872 * enlightened implementation is not possible. If that changes, we'd
6875 if (WARN_ON_ONCE(size < 0))
6879 * The pad comes from ALIGN()ing data->aux_size up to u64 in
6880 * perf_prepare_sample_aux(), so should not be more than that.
6882 pad = data->aux_size - size;
6883 if (WARN_ON_ONCE(pad >= sizeof(u64)))
6888 perf_output_copy(handle, &zero, pad);
6892 ring_buffer_put(rb);
6895 static void __perf_event_header__init_id(struct perf_event_header *header,
6896 struct perf_sample_data *data,
6897 struct perf_event *event)
6899 u64 sample_type = event->attr.sample_type;
6901 data->type = sample_type;
6902 header->size += event->id_header_size;
6904 if (sample_type & PERF_SAMPLE_TID) {
6905 /* namespace issues */
6906 data->tid_entry.pid = perf_event_pid(event, current);
6907 data->tid_entry.tid = perf_event_tid(event, current);
6910 if (sample_type & PERF_SAMPLE_TIME)
6911 data->time = perf_event_clock(event);
6913 if (sample_type & (PERF_SAMPLE_ID | PERF_SAMPLE_IDENTIFIER))
6914 data->id = primary_event_id(event);
6916 if (sample_type & PERF_SAMPLE_STREAM_ID)
6917 data->stream_id = event->id;
6919 if (sample_type & PERF_SAMPLE_CPU) {
6920 data->cpu_entry.cpu = raw_smp_processor_id();
6921 data->cpu_entry.reserved = 0;
6925 void perf_event_header__init_id(struct perf_event_header *header,
6926 struct perf_sample_data *data,
6927 struct perf_event *event)
6929 if (event->attr.sample_id_all)
6930 __perf_event_header__init_id(header, data, event);
6933 static void __perf_event__output_id_sample(struct perf_output_handle *handle,
6934 struct perf_sample_data *data)
6936 u64 sample_type = data->type;
6938 if (sample_type & PERF_SAMPLE_TID)
6939 perf_output_put(handle, data->tid_entry);
6941 if (sample_type & PERF_SAMPLE_TIME)
6942 perf_output_put(handle, data->time);
6944 if (sample_type & PERF_SAMPLE_ID)
6945 perf_output_put(handle, data->id);
6947 if (sample_type & PERF_SAMPLE_STREAM_ID)
6948 perf_output_put(handle, data->stream_id);
6950 if (sample_type & PERF_SAMPLE_CPU)
6951 perf_output_put(handle, data->cpu_entry);
6953 if (sample_type & PERF_SAMPLE_IDENTIFIER)
6954 perf_output_put(handle, data->id);
6957 void perf_event__output_id_sample(struct perf_event *event,
6958 struct perf_output_handle *handle,
6959 struct perf_sample_data *sample)
6961 if (event->attr.sample_id_all)
6962 __perf_event__output_id_sample(handle, sample);
6965 static void perf_output_read_one(struct perf_output_handle *handle,
6966 struct perf_event *event,
6967 u64 enabled, u64 running)
6969 u64 read_format = event->attr.read_format;
6973 values[n++] = perf_event_count(event);
6974 if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED) {
6975 values[n++] = enabled +
6976 atomic64_read(&event->child_total_time_enabled);
6978 if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING) {
6979 values[n++] = running +
6980 atomic64_read(&event->child_total_time_running);
6982 if (read_format & PERF_FORMAT_ID)
6983 values[n++] = primary_event_id(event);
6985 __output_copy(handle, values, n * sizeof(u64));
6988 static void perf_output_read_group(struct perf_output_handle *handle,
6989 struct perf_event *event,
6990 u64 enabled, u64 running)
6992 struct perf_event *leader = event->group_leader, *sub;
6993 u64 read_format = event->attr.read_format;
6997 values[n++] = 1 + leader->nr_siblings;
6999 if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED)
7000 values[n++] = enabled;
7002 if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING)
7003 values[n++] = running;
7005 if ((leader != event) &&
7006 (leader->state == PERF_EVENT_STATE_ACTIVE))
7007 leader->pmu->read(leader);
7009 values[n++] = perf_event_count(leader);
7010 if (read_format & PERF_FORMAT_ID)
7011 values[n++] = primary_event_id(leader);
7013 __output_copy(handle, values, n * sizeof(u64));
7015 for_each_sibling_event(sub, leader) {
7018 if ((sub != event) &&
7019 (sub->state == PERF_EVENT_STATE_ACTIVE))
7020 sub->pmu->read(sub);
7022 values[n++] = perf_event_count(sub);
7023 if (read_format & PERF_FORMAT_ID)
7024 values[n++] = primary_event_id(sub);
7026 __output_copy(handle, values, n * sizeof(u64));
7030 #define PERF_FORMAT_TOTAL_TIMES (PERF_FORMAT_TOTAL_TIME_ENABLED|\
7031 PERF_FORMAT_TOTAL_TIME_RUNNING)
7034 * XXX PERF_SAMPLE_READ vs inherited events seems difficult.
7036 * The problem is that its both hard and excessively expensive to iterate the
7037 * child list, not to mention that its impossible to IPI the children running
7038 * on another CPU, from interrupt/NMI context.
7040 static void perf_output_read(struct perf_output_handle *handle,
7041 struct perf_event *event)
7043 u64 enabled = 0, running = 0, now;
7044 u64 read_format = event->attr.read_format;
7047 * compute total_time_enabled, total_time_running
7048 * based on snapshot values taken when the event
7049 * was last scheduled in.
7051 * we cannot simply called update_context_time()
7052 * because of locking issue as we are called in
7055 if (read_format & PERF_FORMAT_TOTAL_TIMES)
7056 calc_timer_values(event, &now, &enabled, &running);
7058 if (event->attr.read_format & PERF_FORMAT_GROUP)
7059 perf_output_read_group(handle, event, enabled, running);
7061 perf_output_read_one(handle, event, enabled, running);
7064 static inline bool perf_sample_save_hw_index(struct perf_event *event)
7066 return event->attr.branch_sample_type & PERF_SAMPLE_BRANCH_HW_INDEX;
7069 void perf_output_sample(struct perf_output_handle *handle,
7070 struct perf_event_header *header,
7071 struct perf_sample_data *data,
7072 struct perf_event *event)
7074 u64 sample_type = data->type;
7076 perf_output_put(handle, *header);
7078 if (sample_type & PERF_SAMPLE_IDENTIFIER)
7079 perf_output_put(handle, data->id);
7081 if (sample_type & PERF_SAMPLE_IP)
7082 perf_output_put(handle, data->ip);
7084 if (sample_type & PERF_SAMPLE_TID)
7085 perf_output_put(handle, data->tid_entry);
7087 if (sample_type & PERF_SAMPLE_TIME)
7088 perf_output_put(handle, data->time);
7090 if (sample_type & PERF_SAMPLE_ADDR)
7091 perf_output_put(handle, data->addr);
7093 if (sample_type & PERF_SAMPLE_ID)
7094 perf_output_put(handle, data->id);
7096 if (sample_type & PERF_SAMPLE_STREAM_ID)
7097 perf_output_put(handle, data->stream_id);
7099 if (sample_type & PERF_SAMPLE_CPU)
7100 perf_output_put(handle, data->cpu_entry);
7102 if (sample_type & PERF_SAMPLE_PERIOD)
7103 perf_output_put(handle, data->period);
7105 if (sample_type & PERF_SAMPLE_READ)
7106 perf_output_read(handle, event);
7108 if (sample_type & PERF_SAMPLE_CALLCHAIN) {
7111 size += data->callchain->nr;
7112 size *= sizeof(u64);
7113 __output_copy(handle, data->callchain, size);
7116 if (sample_type & PERF_SAMPLE_RAW) {
7117 struct perf_raw_record *raw = data->raw;
7120 struct perf_raw_frag *frag = &raw->frag;
7122 perf_output_put(handle, raw->size);
7125 __output_custom(handle, frag->copy,
7126 frag->data, frag->size);
7128 __output_copy(handle, frag->data,
7131 if (perf_raw_frag_last(frag))
7136 __output_skip(handle, NULL, frag->pad);
7142 .size = sizeof(u32),
7145 perf_output_put(handle, raw);
7149 if (sample_type & PERF_SAMPLE_BRANCH_STACK) {
7150 if (data->br_stack) {
7153 size = data->br_stack->nr
7154 * sizeof(struct perf_branch_entry);
7156 perf_output_put(handle, data->br_stack->nr);
7157 if (perf_sample_save_hw_index(event))
7158 perf_output_put(handle, data->br_stack->hw_idx);
7159 perf_output_copy(handle, data->br_stack->entries, size);
7162 * we always store at least the value of nr
7165 perf_output_put(handle, nr);
7169 if (sample_type & PERF_SAMPLE_REGS_USER) {
7170 u64 abi = data->regs_user.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_user;
7180 perf_output_sample_regs(handle,
7181 data->regs_user.regs,
7186 if (sample_type & PERF_SAMPLE_STACK_USER) {
7187 perf_output_sample_ustack(handle,
7188 data->stack_user_size,
7189 data->regs_user.regs);
7192 if (sample_type & PERF_SAMPLE_WEIGHT_TYPE)
7193 perf_output_put(handle, data->weight.full);
7195 if (sample_type & PERF_SAMPLE_DATA_SRC)
7196 perf_output_put(handle, data->data_src.val);
7198 if (sample_type & PERF_SAMPLE_TRANSACTION)
7199 perf_output_put(handle, data->txn);
7201 if (sample_type & PERF_SAMPLE_REGS_INTR) {
7202 u64 abi = data->regs_intr.abi;
7204 * If there are no regs to dump, notice it through
7205 * first u64 being zero (PERF_SAMPLE_REGS_ABI_NONE).
7207 perf_output_put(handle, abi);
7210 u64 mask = event->attr.sample_regs_intr;
7212 perf_output_sample_regs(handle,
7213 data->regs_intr.regs,
7218 if (sample_type & PERF_SAMPLE_PHYS_ADDR)
7219 perf_output_put(handle, data->phys_addr);
7221 if (sample_type & PERF_SAMPLE_CGROUP)
7222 perf_output_put(handle, data->cgroup);
7224 if (sample_type & PERF_SAMPLE_DATA_PAGE_SIZE)
7225 perf_output_put(handle, data->data_page_size);
7227 if (sample_type & PERF_SAMPLE_CODE_PAGE_SIZE)
7228 perf_output_put(handle, data->code_page_size);
7230 if (sample_type & PERF_SAMPLE_AUX) {
7231 perf_output_put(handle, data->aux_size);
7234 perf_aux_sample_output(event, handle, data);
7237 if (!event->attr.watermark) {
7238 int wakeup_events = event->attr.wakeup_events;
7240 if (wakeup_events) {
7241 struct perf_buffer *rb = handle->rb;
7242 int events = local_inc_return(&rb->events);
7244 if (events >= wakeup_events) {
7245 local_sub(wakeup_events, &rb->events);
7246 local_inc(&rb->wakeup);
7252 static u64 perf_virt_to_phys(u64 virt)
7259 if (virt >= TASK_SIZE) {
7260 /* If it's vmalloc()d memory, leave phys_addr as 0 */
7261 if (virt_addr_valid((void *)(uintptr_t)virt) &&
7262 !(virt >= VMALLOC_START && virt < VMALLOC_END))
7263 phys_addr = (u64)virt_to_phys((void *)(uintptr_t)virt);
7266 * Walking the pages tables for user address.
7267 * Interrupts are disabled, so it prevents any tear down
7268 * of the page tables.
7269 * Try IRQ-safe get_user_page_fast_only first.
7270 * If failed, leave phys_addr as 0.
7272 if (current->mm != NULL) {
7275 pagefault_disable();
7276 if (get_user_page_fast_only(virt, 0, &p)) {
7277 phys_addr = page_to_phys(p) + virt % PAGE_SIZE;
7288 * Return the pagetable size of a given virtual address.
7290 static u64 perf_get_pgtable_size(struct mm_struct *mm, unsigned long addr)
7294 #ifdef CONFIG_HAVE_FAST_GUP
7301 pgdp = pgd_offset(mm, addr);
7302 pgd = READ_ONCE(*pgdp);
7307 return pgd_leaf_size(pgd);
7309 p4dp = p4d_offset_lockless(pgdp, pgd, addr);
7310 p4d = READ_ONCE(*p4dp);
7311 if (!p4d_present(p4d))
7315 return p4d_leaf_size(p4d);
7317 pudp = pud_offset_lockless(p4dp, p4d, addr);
7318 pud = READ_ONCE(*pudp);
7319 if (!pud_present(pud))
7323 return pud_leaf_size(pud);
7325 pmdp = pmd_offset_lockless(pudp, pud, addr);
7326 pmd = READ_ONCE(*pmdp);
7327 if (!pmd_present(pmd))
7331 return pmd_leaf_size(pmd);
7333 ptep = pte_offset_map(&pmd, addr);
7334 pte = ptep_get_lockless(ptep);
7335 if (pte_present(pte))
7336 size = pte_leaf_size(pte);
7338 #endif /* CONFIG_HAVE_FAST_GUP */
7343 static u64 perf_get_page_size(unsigned long addr)
7345 struct mm_struct *mm;
7346 unsigned long flags;
7353 * Software page-table walkers must disable IRQs,
7354 * which prevents any tear down of the page tables.
7356 local_irq_save(flags);
7361 * For kernel threads and the like, use init_mm so that
7362 * we can find kernel memory.
7367 size = perf_get_pgtable_size(mm, addr);
7369 local_irq_restore(flags);
7374 static struct perf_callchain_entry __empty_callchain = { .nr = 0, };
7376 struct perf_callchain_entry *
7377 perf_callchain(struct perf_event *event, struct pt_regs *regs)
7379 bool kernel = !event->attr.exclude_callchain_kernel;
7380 bool user = !event->attr.exclude_callchain_user;
7381 /* Disallow cross-task user callchains. */
7382 bool crosstask = event->ctx->task && event->ctx->task != current;
7383 const u32 max_stack = event->attr.sample_max_stack;
7384 struct perf_callchain_entry *callchain;
7386 if (!kernel && !user)
7387 return &__empty_callchain;
7389 callchain = get_perf_callchain(regs, 0, kernel, user,
7390 max_stack, crosstask, true);
7391 return callchain ?: &__empty_callchain;
7394 void perf_prepare_sample(struct perf_event_header *header,
7395 struct perf_sample_data *data,
7396 struct perf_event *event,
7397 struct pt_regs *regs)
7399 u64 sample_type = event->attr.sample_type;
7401 header->type = PERF_RECORD_SAMPLE;
7402 header->size = sizeof(*header) + event->header_size;
7405 header->misc |= perf_misc_flags(regs);
7407 __perf_event_header__init_id(header, data, event);
7409 if (sample_type & (PERF_SAMPLE_IP | PERF_SAMPLE_CODE_PAGE_SIZE))
7410 data->ip = perf_instruction_pointer(regs);
7412 if (sample_type & PERF_SAMPLE_CALLCHAIN) {
7415 if (!(sample_type & __PERF_SAMPLE_CALLCHAIN_EARLY))
7416 data->callchain = perf_callchain(event, regs);
7418 size += data->callchain->nr;
7420 header->size += size * sizeof(u64);
7423 if (sample_type & PERF_SAMPLE_RAW) {
7424 struct perf_raw_record *raw = data->raw;
7428 struct perf_raw_frag *frag = &raw->frag;
7433 if (perf_raw_frag_last(frag))
7438 size = round_up(sum + sizeof(u32), sizeof(u64));
7439 raw->size = size - sizeof(u32);
7440 frag->pad = raw->size - sum;
7445 header->size += size;
7448 if (sample_type & PERF_SAMPLE_BRANCH_STACK) {
7449 int size = sizeof(u64); /* nr */
7450 if (data->br_stack) {
7451 if (perf_sample_save_hw_index(event))
7452 size += sizeof(u64);
7454 size += data->br_stack->nr
7455 * sizeof(struct perf_branch_entry);
7457 header->size += size;
7460 if (sample_type & (PERF_SAMPLE_REGS_USER | PERF_SAMPLE_STACK_USER))
7461 perf_sample_regs_user(&data->regs_user, regs);
7463 if (sample_type & PERF_SAMPLE_REGS_USER) {
7464 /* regs dump ABI info */
7465 int size = sizeof(u64);
7467 if (data->regs_user.regs) {
7468 u64 mask = event->attr.sample_regs_user;
7469 size += hweight64(mask) * sizeof(u64);
7472 header->size += size;
7475 if (sample_type & PERF_SAMPLE_STACK_USER) {
7477 * Either we need PERF_SAMPLE_STACK_USER bit to be always
7478 * processed as the last one or have additional check added
7479 * in case new sample type is added, because we could eat
7480 * up the rest of the sample size.
7482 u16 stack_size = event->attr.sample_stack_user;
7483 u16 size = sizeof(u64);
7485 stack_size = perf_sample_ustack_size(stack_size, header->size,
7486 data->regs_user.regs);
7489 * If there is something to dump, add space for the dump
7490 * itself and for the field that tells the dynamic size,
7491 * which is how many have been actually dumped.
7494 size += sizeof(u64) + stack_size;
7496 data->stack_user_size = stack_size;
7497 header->size += size;
7500 if (sample_type & PERF_SAMPLE_REGS_INTR) {
7501 /* regs dump ABI info */
7502 int size = sizeof(u64);
7504 perf_sample_regs_intr(&data->regs_intr, regs);
7506 if (data->regs_intr.regs) {
7507 u64 mask = event->attr.sample_regs_intr;
7509 size += hweight64(mask) * sizeof(u64);
7512 header->size += size;
7515 if (sample_type & PERF_SAMPLE_PHYS_ADDR)
7516 data->phys_addr = perf_virt_to_phys(data->addr);
7518 #ifdef CONFIG_CGROUP_PERF
7519 if (sample_type & PERF_SAMPLE_CGROUP) {
7520 struct cgroup *cgrp;
7522 /* protected by RCU */
7523 cgrp = task_css_check(current, perf_event_cgrp_id, 1)->cgroup;
7524 data->cgroup = cgroup_id(cgrp);
7529 * PERF_DATA_PAGE_SIZE requires PERF_SAMPLE_ADDR. If the user doesn't
7530 * require PERF_SAMPLE_ADDR, kernel implicitly retrieve the data->addr,
7531 * but the value will not dump to the userspace.
7533 if (sample_type & PERF_SAMPLE_DATA_PAGE_SIZE)
7534 data->data_page_size = perf_get_page_size(data->addr);
7536 if (sample_type & PERF_SAMPLE_CODE_PAGE_SIZE)
7537 data->code_page_size = perf_get_page_size(data->ip);
7539 if (sample_type & PERF_SAMPLE_AUX) {
7542 header->size += sizeof(u64); /* size */
7545 * Given the 16bit nature of header::size, an AUX sample can
7546 * easily overflow it, what with all the preceding sample bits.
7547 * Make sure this doesn't happen by using up to U16_MAX bytes
7548 * per sample in total (rounded down to 8 byte boundary).
7550 size = min_t(size_t, U16_MAX - header->size,
7551 event->attr.aux_sample_size);
7552 size = rounddown(size, 8);
7553 size = perf_prepare_sample_aux(event, data, size);
7555 WARN_ON_ONCE(size + header->size > U16_MAX);
7556 header->size += size;
7559 * If you're adding more sample types here, you likely need to do
7560 * something about the overflowing header::size, like repurpose the
7561 * lowest 3 bits of size, which should be always zero at the moment.
7562 * This raises a more important question, do we really need 512k sized
7563 * samples and why, so good argumentation is in order for whatever you
7566 WARN_ON_ONCE(header->size & 7);
7569 static __always_inline int
7570 __perf_event_output(struct perf_event *event,
7571 struct perf_sample_data *data,
7572 struct pt_regs *regs,
7573 int (*output_begin)(struct perf_output_handle *,
7574 struct perf_sample_data *,
7575 struct perf_event *,
7578 struct perf_output_handle handle;
7579 struct perf_event_header header;
7582 /* protect the callchain buffers */
7585 perf_prepare_sample(&header, data, event, regs);
7587 err = output_begin(&handle, data, event, header.size);
7591 perf_output_sample(&handle, &header, data, event);
7593 perf_output_end(&handle);
7601 perf_event_output_forward(struct perf_event *event,
7602 struct perf_sample_data *data,
7603 struct pt_regs *regs)
7605 __perf_event_output(event, data, regs, perf_output_begin_forward);
7609 perf_event_output_backward(struct perf_event *event,
7610 struct perf_sample_data *data,
7611 struct pt_regs *regs)
7613 __perf_event_output(event, data, regs, perf_output_begin_backward);
7617 perf_event_output(struct perf_event *event,
7618 struct perf_sample_data *data,
7619 struct pt_regs *regs)
7621 return __perf_event_output(event, data, regs, perf_output_begin);
7628 struct perf_read_event {
7629 struct perf_event_header header;
7636 perf_event_read_event(struct perf_event *event,
7637 struct task_struct *task)
7639 struct perf_output_handle handle;
7640 struct perf_sample_data sample;
7641 struct perf_read_event read_event = {
7643 .type = PERF_RECORD_READ,
7645 .size = sizeof(read_event) + event->read_size,
7647 .pid = perf_event_pid(event, task),
7648 .tid = perf_event_tid(event, task),
7652 perf_event_header__init_id(&read_event.header, &sample, event);
7653 ret = perf_output_begin(&handle, &sample, event, read_event.header.size);
7657 perf_output_put(&handle, read_event);
7658 perf_output_read(&handle, event);
7659 perf_event__output_id_sample(event, &handle, &sample);
7661 perf_output_end(&handle);
7664 typedef void (perf_iterate_f)(struct perf_event *event, void *data);
7667 perf_iterate_ctx(struct perf_event_context *ctx,
7668 perf_iterate_f output,
7669 void *data, bool all)
7671 struct perf_event *event;
7673 list_for_each_entry_rcu(event, &ctx->event_list, event_entry) {
7675 if (event->state < PERF_EVENT_STATE_INACTIVE)
7677 if (!event_filter_match(event))
7681 output(event, data);
7685 static void perf_iterate_sb_cpu(perf_iterate_f output, void *data)
7687 struct pmu_event_list *pel = this_cpu_ptr(&pmu_sb_events);
7688 struct perf_event *event;
7690 list_for_each_entry_rcu(event, &pel->list, sb_list) {
7692 * Skip events that are not fully formed yet; ensure that
7693 * if we observe event->ctx, both event and ctx will be
7694 * complete enough. See perf_install_in_context().
7696 if (!smp_load_acquire(&event->ctx))
7699 if (event->state < PERF_EVENT_STATE_INACTIVE)
7701 if (!event_filter_match(event))
7703 output(event, data);
7708 * Iterate all events that need to receive side-band events.
7710 * For new callers; ensure that account_pmu_sb_event() includes
7711 * your event, otherwise it might not get delivered.
7714 perf_iterate_sb(perf_iterate_f output, void *data,
7715 struct perf_event_context *task_ctx)
7717 struct perf_event_context *ctx;
7724 * If we have task_ctx != NULL we only notify the task context itself.
7725 * The task_ctx is set only for EXIT events before releasing task
7729 perf_iterate_ctx(task_ctx, output, data, false);
7733 perf_iterate_sb_cpu(output, data);
7735 for_each_task_context_nr(ctxn) {
7736 ctx = rcu_dereference(current->perf_event_ctxp[ctxn]);
7738 perf_iterate_ctx(ctx, output, data, false);
7746 * Clear all file-based filters at exec, they'll have to be
7747 * re-instated when/if these objects are mmapped again.
7749 static void perf_event_addr_filters_exec(struct perf_event *event, void *data)
7751 struct perf_addr_filters_head *ifh = perf_event_addr_filters(event);
7752 struct perf_addr_filter *filter;
7753 unsigned int restart = 0, count = 0;
7754 unsigned long flags;
7756 if (!has_addr_filter(event))
7759 raw_spin_lock_irqsave(&ifh->lock, flags);
7760 list_for_each_entry(filter, &ifh->list, entry) {
7761 if (filter->path.dentry) {
7762 event->addr_filter_ranges[count].start = 0;
7763 event->addr_filter_ranges[count].size = 0;
7771 event->addr_filters_gen++;
7772 raw_spin_unlock_irqrestore(&ifh->lock, flags);
7775 perf_event_stop(event, 1);
7778 void perf_event_exec(void)
7780 struct perf_event_context *ctx;
7783 for_each_task_context_nr(ctxn) {
7784 perf_event_enable_on_exec(ctxn);
7785 perf_event_remove_on_exec(ctxn);
7788 ctx = rcu_dereference(current->perf_event_ctxp[ctxn]);
7790 perf_iterate_ctx(ctx, perf_event_addr_filters_exec,
7797 struct remote_output {
7798 struct perf_buffer *rb;
7802 static void __perf_event_output_stop(struct perf_event *event, void *data)
7804 struct perf_event *parent = event->parent;
7805 struct remote_output *ro = data;
7806 struct perf_buffer *rb = ro->rb;
7807 struct stop_event_data sd = {
7811 if (!has_aux(event))
7818 * In case of inheritance, it will be the parent that links to the
7819 * ring-buffer, but it will be the child that's actually using it.
7821 * We are using event::rb to determine if the event should be stopped,
7822 * however this may race with ring_buffer_attach() (through set_output),
7823 * which will make us skip the event that actually needs to be stopped.
7824 * So ring_buffer_attach() has to stop an aux event before re-assigning
7827 if (rcu_dereference(parent->rb) == rb)
7828 ro->err = __perf_event_stop(&sd);
7831 static int __perf_pmu_output_stop(void *info)
7833 struct perf_event *event = info;
7834 struct pmu *pmu = event->ctx->pmu;
7835 struct perf_cpu_context *cpuctx = this_cpu_ptr(pmu->pmu_cpu_context);
7836 struct remote_output ro = {
7841 perf_iterate_ctx(&cpuctx->ctx, __perf_event_output_stop, &ro, false);
7842 if (cpuctx->task_ctx)
7843 perf_iterate_ctx(cpuctx->task_ctx, __perf_event_output_stop,
7850 static void perf_pmu_output_stop(struct perf_event *event)
7852 struct perf_event *iter;
7857 list_for_each_entry_rcu(iter, &event->rb->event_list, rb_entry) {
7859 * For per-CPU events, we need to make sure that neither they
7860 * nor their children are running; for cpu==-1 events it's
7861 * sufficient to stop the event itself if it's active, since
7862 * it can't have children.
7866 cpu = READ_ONCE(iter->oncpu);
7871 err = cpu_function_call(cpu, __perf_pmu_output_stop, event);
7872 if (err == -EAGAIN) {
7881 * task tracking -- fork/exit
7883 * enabled by: attr.comm | attr.mmap | attr.mmap2 | attr.mmap_data | attr.task
7886 struct perf_task_event {
7887 struct task_struct *task;
7888 struct perf_event_context *task_ctx;
7891 struct perf_event_header header;
7901 static int perf_event_task_match(struct perf_event *event)
7903 return event->attr.comm || event->attr.mmap ||
7904 event->attr.mmap2 || event->attr.mmap_data ||
7908 static void perf_event_task_output(struct perf_event *event,
7911 struct perf_task_event *task_event = data;
7912 struct perf_output_handle handle;
7913 struct perf_sample_data sample;
7914 struct task_struct *task = task_event->task;
7915 int ret, size = task_event->event_id.header.size;
7917 if (!perf_event_task_match(event))
7920 perf_event_header__init_id(&task_event->event_id.header, &sample, event);
7922 ret = perf_output_begin(&handle, &sample, event,
7923 task_event->event_id.header.size);
7927 task_event->event_id.pid = perf_event_pid(event, task);
7928 task_event->event_id.tid = perf_event_tid(event, task);
7930 if (task_event->event_id.header.type == PERF_RECORD_EXIT) {
7931 task_event->event_id.ppid = perf_event_pid(event,
7933 task_event->event_id.ptid = perf_event_pid(event,
7935 } else { /* PERF_RECORD_FORK */
7936 task_event->event_id.ppid = perf_event_pid(event, current);
7937 task_event->event_id.ptid = perf_event_tid(event, current);
7940 task_event->event_id.time = perf_event_clock(event);
7942 perf_output_put(&handle, task_event->event_id);
7944 perf_event__output_id_sample(event, &handle, &sample);
7946 perf_output_end(&handle);
7948 task_event->event_id.header.size = size;
7951 static void perf_event_task(struct task_struct *task,
7952 struct perf_event_context *task_ctx,
7955 struct perf_task_event task_event;
7957 if (!atomic_read(&nr_comm_events) &&
7958 !atomic_read(&nr_mmap_events) &&
7959 !atomic_read(&nr_task_events))
7962 task_event = (struct perf_task_event){
7964 .task_ctx = task_ctx,
7967 .type = new ? PERF_RECORD_FORK : PERF_RECORD_EXIT,
7969 .size = sizeof(task_event.event_id),
7979 perf_iterate_sb(perf_event_task_output,
7984 void perf_event_fork(struct task_struct *task)
7986 perf_event_task(task, NULL, 1);
7987 perf_event_namespaces(task);
7994 struct perf_comm_event {
7995 struct task_struct *task;
8000 struct perf_event_header header;
8007 static int perf_event_comm_match(struct perf_event *event)
8009 return event->attr.comm;
8012 static void perf_event_comm_output(struct perf_event *event,
8015 struct perf_comm_event *comm_event = data;
8016 struct perf_output_handle handle;
8017 struct perf_sample_data sample;
8018 int size = comm_event->event_id.header.size;
8021 if (!perf_event_comm_match(event))
8024 perf_event_header__init_id(&comm_event->event_id.header, &sample, event);
8025 ret = perf_output_begin(&handle, &sample, event,
8026 comm_event->event_id.header.size);
8031 comm_event->event_id.pid = perf_event_pid(event, comm_event->task);
8032 comm_event->event_id.tid = perf_event_tid(event, comm_event->task);
8034 perf_output_put(&handle, comm_event->event_id);
8035 __output_copy(&handle, comm_event->comm,
8036 comm_event->comm_size);
8038 perf_event__output_id_sample(event, &handle, &sample);
8040 perf_output_end(&handle);
8042 comm_event->event_id.header.size = size;
8045 static void perf_event_comm_event(struct perf_comm_event *comm_event)
8047 char comm[TASK_COMM_LEN];
8050 memset(comm, 0, sizeof(comm));
8051 strlcpy(comm, comm_event->task->comm, sizeof(comm));
8052 size = ALIGN(strlen(comm)+1, sizeof(u64));
8054 comm_event->comm = comm;
8055 comm_event->comm_size = size;
8057 comm_event->event_id.header.size = sizeof(comm_event->event_id) + size;
8059 perf_iterate_sb(perf_event_comm_output,
8064 void perf_event_comm(struct task_struct *task, bool exec)
8066 struct perf_comm_event comm_event;
8068 if (!atomic_read(&nr_comm_events))
8071 comm_event = (struct perf_comm_event){
8077 .type = PERF_RECORD_COMM,
8078 .misc = exec ? PERF_RECORD_MISC_COMM_EXEC : 0,
8086 perf_event_comm_event(&comm_event);
8090 * namespaces tracking
8093 struct perf_namespaces_event {
8094 struct task_struct *task;
8097 struct perf_event_header header;
8102 struct perf_ns_link_info link_info[NR_NAMESPACES];
8106 static int perf_event_namespaces_match(struct perf_event *event)
8108 return event->attr.namespaces;
8111 static void perf_event_namespaces_output(struct perf_event *event,
8114 struct perf_namespaces_event *namespaces_event = data;
8115 struct perf_output_handle handle;
8116 struct perf_sample_data sample;
8117 u16 header_size = namespaces_event->event_id.header.size;
8120 if (!perf_event_namespaces_match(event))
8123 perf_event_header__init_id(&namespaces_event->event_id.header,
8125 ret = perf_output_begin(&handle, &sample, event,
8126 namespaces_event->event_id.header.size);
8130 namespaces_event->event_id.pid = perf_event_pid(event,
8131 namespaces_event->task);
8132 namespaces_event->event_id.tid = perf_event_tid(event,
8133 namespaces_event->task);
8135 perf_output_put(&handle, namespaces_event->event_id);
8137 perf_event__output_id_sample(event, &handle, &sample);
8139 perf_output_end(&handle);
8141 namespaces_event->event_id.header.size = header_size;
8144 static void perf_fill_ns_link_info(struct perf_ns_link_info *ns_link_info,
8145 struct task_struct *task,
8146 const struct proc_ns_operations *ns_ops)
8148 struct path ns_path;
8149 struct inode *ns_inode;
8152 error = ns_get_path(&ns_path, task, ns_ops);
8154 ns_inode = ns_path.dentry->d_inode;
8155 ns_link_info->dev = new_encode_dev(ns_inode->i_sb->s_dev);
8156 ns_link_info->ino = ns_inode->i_ino;
8161 void perf_event_namespaces(struct task_struct *task)
8163 struct perf_namespaces_event namespaces_event;
8164 struct perf_ns_link_info *ns_link_info;
8166 if (!atomic_read(&nr_namespaces_events))
8169 namespaces_event = (struct perf_namespaces_event){
8173 .type = PERF_RECORD_NAMESPACES,
8175 .size = sizeof(namespaces_event.event_id),
8179 .nr_namespaces = NR_NAMESPACES,
8180 /* .link_info[NR_NAMESPACES] */
8184 ns_link_info = namespaces_event.event_id.link_info;
8186 perf_fill_ns_link_info(&ns_link_info[MNT_NS_INDEX],
8187 task, &mntns_operations);
8189 #ifdef CONFIG_USER_NS
8190 perf_fill_ns_link_info(&ns_link_info[USER_NS_INDEX],
8191 task, &userns_operations);
8193 #ifdef CONFIG_NET_NS
8194 perf_fill_ns_link_info(&ns_link_info[NET_NS_INDEX],
8195 task, &netns_operations);
8197 #ifdef CONFIG_UTS_NS
8198 perf_fill_ns_link_info(&ns_link_info[UTS_NS_INDEX],
8199 task, &utsns_operations);
8201 #ifdef CONFIG_IPC_NS
8202 perf_fill_ns_link_info(&ns_link_info[IPC_NS_INDEX],
8203 task, &ipcns_operations);
8205 #ifdef CONFIG_PID_NS
8206 perf_fill_ns_link_info(&ns_link_info[PID_NS_INDEX],
8207 task, &pidns_operations);
8209 #ifdef CONFIG_CGROUPS
8210 perf_fill_ns_link_info(&ns_link_info[CGROUP_NS_INDEX],
8211 task, &cgroupns_operations);
8214 perf_iterate_sb(perf_event_namespaces_output,
8222 #ifdef CONFIG_CGROUP_PERF
8224 struct perf_cgroup_event {
8228 struct perf_event_header header;
8234 static int perf_event_cgroup_match(struct perf_event *event)
8236 return event->attr.cgroup;
8239 static void perf_event_cgroup_output(struct perf_event *event, void *data)
8241 struct perf_cgroup_event *cgroup_event = data;
8242 struct perf_output_handle handle;
8243 struct perf_sample_data sample;
8244 u16 header_size = cgroup_event->event_id.header.size;
8247 if (!perf_event_cgroup_match(event))
8250 perf_event_header__init_id(&cgroup_event->event_id.header,
8252 ret = perf_output_begin(&handle, &sample, event,
8253 cgroup_event->event_id.header.size);
8257 perf_output_put(&handle, cgroup_event->event_id);
8258 __output_copy(&handle, cgroup_event->path, cgroup_event->path_size);
8260 perf_event__output_id_sample(event, &handle, &sample);
8262 perf_output_end(&handle);
8264 cgroup_event->event_id.header.size = header_size;
8267 static void perf_event_cgroup(struct cgroup *cgrp)
8269 struct perf_cgroup_event cgroup_event;
8270 char path_enomem[16] = "//enomem";
8274 if (!atomic_read(&nr_cgroup_events))
8277 cgroup_event = (struct perf_cgroup_event){
8280 .type = PERF_RECORD_CGROUP,
8282 .size = sizeof(cgroup_event.event_id),
8284 .id = cgroup_id(cgrp),
8288 pathname = kmalloc(PATH_MAX, GFP_KERNEL);
8289 if (pathname == NULL) {
8290 cgroup_event.path = path_enomem;
8292 /* just to be sure to have enough space for alignment */
8293 cgroup_path(cgrp, pathname, PATH_MAX - sizeof(u64));
8294 cgroup_event.path = pathname;
8298 * Since our buffer works in 8 byte units we need to align our string
8299 * size to a multiple of 8. However, we must guarantee the tail end is
8300 * zero'd out to avoid leaking random bits to userspace.
8302 size = strlen(cgroup_event.path) + 1;
8303 while (!IS_ALIGNED(size, sizeof(u64)))
8304 cgroup_event.path[size++] = '\0';
8306 cgroup_event.event_id.header.size += size;
8307 cgroup_event.path_size = size;
8309 perf_iterate_sb(perf_event_cgroup_output,
8322 struct perf_mmap_event {
8323 struct vm_area_struct *vma;
8325 const char *file_name;
8331 u8 build_id[BUILD_ID_SIZE_MAX];
8335 struct perf_event_header header;
8345 static int perf_event_mmap_match(struct perf_event *event,
8348 struct perf_mmap_event *mmap_event = data;
8349 struct vm_area_struct *vma = mmap_event->vma;
8350 int executable = vma->vm_flags & VM_EXEC;
8352 return (!executable && event->attr.mmap_data) ||
8353 (executable && (event->attr.mmap || event->attr.mmap2));
8356 static void perf_event_mmap_output(struct perf_event *event,
8359 struct perf_mmap_event *mmap_event = data;
8360 struct perf_output_handle handle;
8361 struct perf_sample_data sample;
8362 int size = mmap_event->event_id.header.size;
8363 u32 type = mmap_event->event_id.header.type;
8367 if (!perf_event_mmap_match(event, data))
8370 if (event->attr.mmap2) {
8371 mmap_event->event_id.header.type = PERF_RECORD_MMAP2;
8372 mmap_event->event_id.header.size += sizeof(mmap_event->maj);
8373 mmap_event->event_id.header.size += sizeof(mmap_event->min);
8374 mmap_event->event_id.header.size += sizeof(mmap_event->ino);
8375 mmap_event->event_id.header.size += sizeof(mmap_event->ino_generation);
8376 mmap_event->event_id.header.size += sizeof(mmap_event->prot);
8377 mmap_event->event_id.header.size += sizeof(mmap_event->flags);
8380 perf_event_header__init_id(&mmap_event->event_id.header, &sample, event);
8381 ret = perf_output_begin(&handle, &sample, event,
8382 mmap_event->event_id.header.size);
8386 mmap_event->event_id.pid = perf_event_pid(event, current);
8387 mmap_event->event_id.tid = perf_event_tid(event, current);
8389 use_build_id = event->attr.build_id && mmap_event->build_id_size;
8391 if (event->attr.mmap2 && use_build_id)
8392 mmap_event->event_id.header.misc |= PERF_RECORD_MISC_MMAP_BUILD_ID;
8394 perf_output_put(&handle, mmap_event->event_id);
8396 if (event->attr.mmap2) {
8398 u8 size[4] = { (u8) mmap_event->build_id_size, 0, 0, 0 };
8400 __output_copy(&handle, size, 4);
8401 __output_copy(&handle, mmap_event->build_id, BUILD_ID_SIZE_MAX);
8403 perf_output_put(&handle, mmap_event->maj);
8404 perf_output_put(&handle, mmap_event->min);
8405 perf_output_put(&handle, mmap_event->ino);
8406 perf_output_put(&handle, mmap_event->ino_generation);
8408 perf_output_put(&handle, mmap_event->prot);
8409 perf_output_put(&handle, mmap_event->flags);
8412 __output_copy(&handle, mmap_event->file_name,
8413 mmap_event->file_size);
8415 perf_event__output_id_sample(event, &handle, &sample);
8417 perf_output_end(&handle);
8419 mmap_event->event_id.header.size = size;
8420 mmap_event->event_id.header.type = type;
8423 static void perf_event_mmap_event(struct perf_mmap_event *mmap_event)
8425 struct vm_area_struct *vma = mmap_event->vma;
8426 struct file *file = vma->vm_file;
8427 int maj = 0, min = 0;
8428 u64 ino = 0, gen = 0;
8429 u32 prot = 0, flags = 0;
8435 if (vma->vm_flags & VM_READ)
8437 if (vma->vm_flags & VM_WRITE)
8439 if (vma->vm_flags & VM_EXEC)
8442 if (vma->vm_flags & VM_MAYSHARE)
8445 flags = MAP_PRIVATE;
8447 if (vma->vm_flags & VM_LOCKED)
8448 flags |= MAP_LOCKED;
8449 if (is_vm_hugetlb_page(vma))
8450 flags |= MAP_HUGETLB;
8453 struct inode *inode;
8456 buf = kmalloc(PATH_MAX, GFP_KERNEL);
8462 * d_path() works from the end of the rb backwards, so we
8463 * need to add enough zero bytes after the string to handle
8464 * the 64bit alignment we do later.
8466 name = file_path(file, buf, PATH_MAX - sizeof(u64));
8471 inode = file_inode(vma->vm_file);
8472 dev = inode->i_sb->s_dev;
8474 gen = inode->i_generation;
8480 if (vma->vm_ops && vma->vm_ops->name) {
8481 name = (char *) vma->vm_ops->name(vma);
8486 name = (char *)arch_vma_name(vma);
8490 if (vma->vm_start <= vma->vm_mm->start_brk &&
8491 vma->vm_end >= vma->vm_mm->brk) {
8495 if (vma->vm_start <= vma->vm_mm->start_stack &&
8496 vma->vm_end >= vma->vm_mm->start_stack) {
8506 strlcpy(tmp, name, sizeof(tmp));
8510 * Since our buffer works in 8 byte units we need to align our string
8511 * size to a multiple of 8. However, we must guarantee the tail end is
8512 * zero'd out to avoid leaking random bits to userspace.
8514 size = strlen(name)+1;
8515 while (!IS_ALIGNED(size, sizeof(u64)))
8516 name[size++] = '\0';
8518 mmap_event->file_name = name;
8519 mmap_event->file_size = size;
8520 mmap_event->maj = maj;
8521 mmap_event->min = min;
8522 mmap_event->ino = ino;
8523 mmap_event->ino_generation = gen;
8524 mmap_event->prot = prot;
8525 mmap_event->flags = flags;
8527 if (!(vma->vm_flags & VM_EXEC))
8528 mmap_event->event_id.header.misc |= PERF_RECORD_MISC_MMAP_DATA;
8530 mmap_event->event_id.header.size = sizeof(mmap_event->event_id) + size;
8532 if (atomic_read(&nr_build_id_events))
8533 build_id_parse(vma, mmap_event->build_id, &mmap_event->build_id_size);
8535 perf_iterate_sb(perf_event_mmap_output,
8543 * Check whether inode and address range match filter criteria.
8545 static bool perf_addr_filter_match(struct perf_addr_filter *filter,
8546 struct file *file, unsigned long offset,
8549 /* d_inode(NULL) won't be equal to any mapped user-space file */
8550 if (!filter->path.dentry)
8553 if (d_inode(filter->path.dentry) != file_inode(file))
8556 if (filter->offset > offset + size)
8559 if (filter->offset + filter->size < offset)
8565 static bool perf_addr_filter_vma_adjust(struct perf_addr_filter *filter,
8566 struct vm_area_struct *vma,
8567 struct perf_addr_filter_range *fr)
8569 unsigned long vma_size = vma->vm_end - vma->vm_start;
8570 unsigned long off = vma->vm_pgoff << PAGE_SHIFT;
8571 struct file *file = vma->vm_file;
8573 if (!perf_addr_filter_match(filter, file, off, vma_size))
8576 if (filter->offset < off) {
8577 fr->start = vma->vm_start;
8578 fr->size = min(vma_size, filter->size - (off - filter->offset));
8580 fr->start = vma->vm_start + filter->offset - off;
8581 fr->size = min(vma->vm_end - fr->start, filter->size);
8587 static void __perf_addr_filters_adjust(struct perf_event *event, void *data)
8589 struct perf_addr_filters_head *ifh = perf_event_addr_filters(event);
8590 struct vm_area_struct *vma = data;
8591 struct perf_addr_filter *filter;
8592 unsigned int restart = 0, count = 0;
8593 unsigned long flags;
8595 if (!has_addr_filter(event))
8601 raw_spin_lock_irqsave(&ifh->lock, flags);
8602 list_for_each_entry(filter, &ifh->list, entry) {
8603 if (perf_addr_filter_vma_adjust(filter, vma,
8604 &event->addr_filter_ranges[count]))
8611 event->addr_filters_gen++;
8612 raw_spin_unlock_irqrestore(&ifh->lock, flags);
8615 perf_event_stop(event, 1);
8619 * Adjust all task's events' filters to the new vma
8621 static void perf_addr_filters_adjust(struct vm_area_struct *vma)
8623 struct perf_event_context *ctx;
8627 * Data tracing isn't supported yet and as such there is no need
8628 * to keep track of anything that isn't related to executable code:
8630 if (!(vma->vm_flags & VM_EXEC))
8634 for_each_task_context_nr(ctxn) {
8635 ctx = rcu_dereference(current->perf_event_ctxp[ctxn]);
8639 perf_iterate_ctx(ctx, __perf_addr_filters_adjust, vma, true);
8644 void perf_event_mmap(struct vm_area_struct *vma)
8646 struct perf_mmap_event mmap_event;
8648 if (!atomic_read(&nr_mmap_events))
8651 mmap_event = (struct perf_mmap_event){
8657 .type = PERF_RECORD_MMAP,
8658 .misc = PERF_RECORD_MISC_USER,
8663 .start = vma->vm_start,
8664 .len = vma->vm_end - vma->vm_start,
8665 .pgoff = (u64)vma->vm_pgoff << PAGE_SHIFT,
8667 /* .maj (attr_mmap2 only) */
8668 /* .min (attr_mmap2 only) */
8669 /* .ino (attr_mmap2 only) */
8670 /* .ino_generation (attr_mmap2 only) */
8671 /* .prot (attr_mmap2 only) */
8672 /* .flags (attr_mmap2 only) */
8675 perf_addr_filters_adjust(vma);
8676 perf_event_mmap_event(&mmap_event);
8679 void perf_event_aux_event(struct perf_event *event, unsigned long head,
8680 unsigned long size, u64 flags)
8682 struct perf_output_handle handle;
8683 struct perf_sample_data sample;
8684 struct perf_aux_event {
8685 struct perf_event_header header;
8691 .type = PERF_RECORD_AUX,
8693 .size = sizeof(rec),
8701 perf_event_header__init_id(&rec.header, &sample, event);
8702 ret = perf_output_begin(&handle, &sample, event, rec.header.size);
8707 perf_output_put(&handle, rec);
8708 perf_event__output_id_sample(event, &handle, &sample);
8710 perf_output_end(&handle);
8714 * Lost/dropped samples logging
8716 void perf_log_lost_samples(struct perf_event *event, u64 lost)
8718 struct perf_output_handle handle;
8719 struct perf_sample_data sample;
8723 struct perf_event_header header;
8725 } lost_samples_event = {
8727 .type = PERF_RECORD_LOST_SAMPLES,
8729 .size = sizeof(lost_samples_event),
8734 perf_event_header__init_id(&lost_samples_event.header, &sample, event);
8736 ret = perf_output_begin(&handle, &sample, event,
8737 lost_samples_event.header.size);
8741 perf_output_put(&handle, lost_samples_event);
8742 perf_event__output_id_sample(event, &handle, &sample);
8743 perf_output_end(&handle);
8747 * context_switch tracking
8750 struct perf_switch_event {
8751 struct task_struct *task;
8752 struct task_struct *next_prev;
8755 struct perf_event_header header;
8761 static int perf_event_switch_match(struct perf_event *event)
8763 return event->attr.context_switch;
8766 static void perf_event_switch_output(struct perf_event *event, void *data)
8768 struct perf_switch_event *se = data;
8769 struct perf_output_handle handle;
8770 struct perf_sample_data sample;
8773 if (!perf_event_switch_match(event))
8776 /* Only CPU-wide events are allowed to see next/prev pid/tid */
8777 if (event->ctx->task) {
8778 se->event_id.header.type = PERF_RECORD_SWITCH;
8779 se->event_id.header.size = sizeof(se->event_id.header);
8781 se->event_id.header.type = PERF_RECORD_SWITCH_CPU_WIDE;
8782 se->event_id.header.size = sizeof(se->event_id);
8783 se->event_id.next_prev_pid =
8784 perf_event_pid(event, se->next_prev);
8785 se->event_id.next_prev_tid =
8786 perf_event_tid(event, se->next_prev);
8789 perf_event_header__init_id(&se->event_id.header, &sample, event);
8791 ret = perf_output_begin(&handle, &sample, event, se->event_id.header.size);
8795 if (event->ctx->task)
8796 perf_output_put(&handle, se->event_id.header);
8798 perf_output_put(&handle, se->event_id);
8800 perf_event__output_id_sample(event, &handle, &sample);
8802 perf_output_end(&handle);
8805 static void perf_event_switch(struct task_struct *task,
8806 struct task_struct *next_prev, bool sched_in)
8808 struct perf_switch_event switch_event;
8810 /* N.B. caller checks nr_switch_events != 0 */
8812 switch_event = (struct perf_switch_event){
8814 .next_prev = next_prev,
8818 .misc = sched_in ? 0 : PERF_RECORD_MISC_SWITCH_OUT,
8821 /* .next_prev_pid */
8822 /* .next_prev_tid */
8826 if (!sched_in && task->on_rq) {
8827 switch_event.event_id.header.misc |=
8828 PERF_RECORD_MISC_SWITCH_OUT_PREEMPT;
8831 perf_iterate_sb(perf_event_switch_output, &switch_event, NULL);
8835 * IRQ throttle logging
8838 static void perf_log_throttle(struct perf_event *event, int enable)
8840 struct perf_output_handle handle;
8841 struct perf_sample_data sample;
8845 struct perf_event_header header;
8849 } throttle_event = {
8851 .type = PERF_RECORD_THROTTLE,
8853 .size = sizeof(throttle_event),
8855 .time = perf_event_clock(event),
8856 .id = primary_event_id(event),
8857 .stream_id = event->id,
8861 throttle_event.header.type = PERF_RECORD_UNTHROTTLE;
8863 perf_event_header__init_id(&throttle_event.header, &sample, event);
8865 ret = perf_output_begin(&handle, &sample, event,
8866 throttle_event.header.size);
8870 perf_output_put(&handle, throttle_event);
8871 perf_event__output_id_sample(event, &handle, &sample);
8872 perf_output_end(&handle);
8876 * ksymbol register/unregister tracking
8879 struct perf_ksymbol_event {
8883 struct perf_event_header header;
8891 static int perf_event_ksymbol_match(struct perf_event *event)
8893 return event->attr.ksymbol;
8896 static void perf_event_ksymbol_output(struct perf_event *event, void *data)
8898 struct perf_ksymbol_event *ksymbol_event = data;
8899 struct perf_output_handle handle;
8900 struct perf_sample_data sample;
8903 if (!perf_event_ksymbol_match(event))
8906 perf_event_header__init_id(&ksymbol_event->event_id.header,
8908 ret = perf_output_begin(&handle, &sample, event,
8909 ksymbol_event->event_id.header.size);
8913 perf_output_put(&handle, ksymbol_event->event_id);
8914 __output_copy(&handle, ksymbol_event->name, ksymbol_event->name_len);
8915 perf_event__output_id_sample(event, &handle, &sample);
8917 perf_output_end(&handle);
8920 void perf_event_ksymbol(u16 ksym_type, u64 addr, u32 len, bool unregister,
8923 struct perf_ksymbol_event ksymbol_event;
8924 char name[KSYM_NAME_LEN];
8928 if (!atomic_read(&nr_ksymbol_events))
8931 if (ksym_type >= PERF_RECORD_KSYMBOL_TYPE_MAX ||
8932 ksym_type == PERF_RECORD_KSYMBOL_TYPE_UNKNOWN)
8935 strlcpy(name, sym, KSYM_NAME_LEN);
8936 name_len = strlen(name) + 1;
8937 while (!IS_ALIGNED(name_len, sizeof(u64)))
8938 name[name_len++] = '\0';
8939 BUILD_BUG_ON(KSYM_NAME_LEN % sizeof(u64));
8942 flags |= PERF_RECORD_KSYMBOL_FLAGS_UNREGISTER;
8944 ksymbol_event = (struct perf_ksymbol_event){
8946 .name_len = name_len,
8949 .type = PERF_RECORD_KSYMBOL,
8950 .size = sizeof(ksymbol_event.event_id) +
8955 .ksym_type = ksym_type,
8960 perf_iterate_sb(perf_event_ksymbol_output, &ksymbol_event, NULL);
8963 WARN_ONCE(1, "%s: Invalid KSYMBOL type 0x%x\n", __func__, ksym_type);
8967 * bpf program load/unload tracking
8970 struct perf_bpf_event {
8971 struct bpf_prog *prog;
8973 struct perf_event_header header;
8977 u8 tag[BPF_TAG_SIZE];
8981 static int perf_event_bpf_match(struct perf_event *event)
8983 return event->attr.bpf_event;
8986 static void perf_event_bpf_output(struct perf_event *event, void *data)
8988 struct perf_bpf_event *bpf_event = data;
8989 struct perf_output_handle handle;
8990 struct perf_sample_data sample;
8993 if (!perf_event_bpf_match(event))
8996 perf_event_header__init_id(&bpf_event->event_id.header,
8998 ret = perf_output_begin(&handle, data, event,
8999 bpf_event->event_id.header.size);
9003 perf_output_put(&handle, bpf_event->event_id);
9004 perf_event__output_id_sample(event, &handle, &sample);
9006 perf_output_end(&handle);
9009 static void perf_event_bpf_emit_ksymbols(struct bpf_prog *prog,
9010 enum perf_bpf_event_type type)
9012 bool unregister = type == PERF_BPF_EVENT_PROG_UNLOAD;
9015 if (prog->aux->func_cnt == 0) {
9016 perf_event_ksymbol(PERF_RECORD_KSYMBOL_TYPE_BPF,
9017 (u64)(unsigned long)prog->bpf_func,
9018 prog->jited_len, unregister,
9019 prog->aux->ksym.name);
9021 for (i = 0; i < prog->aux->func_cnt; i++) {
9022 struct bpf_prog *subprog = prog->aux->func[i];
9025 PERF_RECORD_KSYMBOL_TYPE_BPF,
9026 (u64)(unsigned long)subprog->bpf_func,
9027 subprog->jited_len, unregister,
9028 prog->aux->ksym.name);
9033 void perf_event_bpf_event(struct bpf_prog *prog,
9034 enum perf_bpf_event_type type,
9037 struct perf_bpf_event bpf_event;
9039 if (type <= PERF_BPF_EVENT_UNKNOWN ||
9040 type >= PERF_BPF_EVENT_MAX)
9044 case PERF_BPF_EVENT_PROG_LOAD:
9045 case PERF_BPF_EVENT_PROG_UNLOAD:
9046 if (atomic_read(&nr_ksymbol_events))
9047 perf_event_bpf_emit_ksymbols(prog, type);
9053 if (!atomic_read(&nr_bpf_events))
9056 bpf_event = (struct perf_bpf_event){
9060 .type = PERF_RECORD_BPF_EVENT,
9061 .size = sizeof(bpf_event.event_id),
9065 .id = prog->aux->id,
9069 BUILD_BUG_ON(BPF_TAG_SIZE % sizeof(u64));
9071 memcpy(bpf_event.event_id.tag, prog->tag, BPF_TAG_SIZE);
9072 perf_iterate_sb(perf_event_bpf_output, &bpf_event, NULL);
9075 struct perf_text_poke_event {
9076 const void *old_bytes;
9077 const void *new_bytes;
9083 struct perf_event_header header;
9089 static int perf_event_text_poke_match(struct perf_event *event)
9091 return event->attr.text_poke;
9094 static void perf_event_text_poke_output(struct perf_event *event, void *data)
9096 struct perf_text_poke_event *text_poke_event = data;
9097 struct perf_output_handle handle;
9098 struct perf_sample_data sample;
9102 if (!perf_event_text_poke_match(event))
9105 perf_event_header__init_id(&text_poke_event->event_id.header, &sample, event);
9107 ret = perf_output_begin(&handle, &sample, event,
9108 text_poke_event->event_id.header.size);
9112 perf_output_put(&handle, text_poke_event->event_id);
9113 perf_output_put(&handle, text_poke_event->old_len);
9114 perf_output_put(&handle, text_poke_event->new_len);
9116 __output_copy(&handle, text_poke_event->old_bytes, text_poke_event->old_len);
9117 __output_copy(&handle, text_poke_event->new_bytes, text_poke_event->new_len);
9119 if (text_poke_event->pad)
9120 __output_copy(&handle, &padding, text_poke_event->pad);
9122 perf_event__output_id_sample(event, &handle, &sample);
9124 perf_output_end(&handle);
9127 void perf_event_text_poke(const void *addr, const void *old_bytes,
9128 size_t old_len, const void *new_bytes, size_t new_len)
9130 struct perf_text_poke_event text_poke_event;
9133 if (!atomic_read(&nr_text_poke_events))
9136 tot = sizeof(text_poke_event.old_len) + old_len;
9137 tot += sizeof(text_poke_event.new_len) + new_len;
9138 pad = ALIGN(tot, sizeof(u64)) - tot;
9140 text_poke_event = (struct perf_text_poke_event){
9141 .old_bytes = old_bytes,
9142 .new_bytes = new_bytes,
9148 .type = PERF_RECORD_TEXT_POKE,
9149 .misc = PERF_RECORD_MISC_KERNEL,
9150 .size = sizeof(text_poke_event.event_id) + tot + pad,
9152 .addr = (unsigned long)addr,
9156 perf_iterate_sb(perf_event_text_poke_output, &text_poke_event, NULL);
9159 void perf_event_itrace_started(struct perf_event *event)
9161 event->attach_state |= PERF_ATTACH_ITRACE;
9164 static void perf_log_itrace_start(struct perf_event *event)
9166 struct perf_output_handle handle;
9167 struct perf_sample_data sample;
9168 struct perf_aux_event {
9169 struct perf_event_header header;
9176 event = event->parent;
9178 if (!(event->pmu->capabilities & PERF_PMU_CAP_ITRACE) ||
9179 event->attach_state & PERF_ATTACH_ITRACE)
9182 rec.header.type = PERF_RECORD_ITRACE_START;
9183 rec.header.misc = 0;
9184 rec.header.size = sizeof(rec);
9185 rec.pid = perf_event_pid(event, current);
9186 rec.tid = perf_event_tid(event, current);
9188 perf_event_header__init_id(&rec.header, &sample, event);
9189 ret = perf_output_begin(&handle, &sample, event, rec.header.size);
9194 perf_output_put(&handle, rec);
9195 perf_event__output_id_sample(event, &handle, &sample);
9197 perf_output_end(&handle);
9200 void perf_report_aux_output_id(struct perf_event *event, u64 hw_id)
9202 struct perf_output_handle handle;
9203 struct perf_sample_data sample;
9204 struct perf_aux_event {
9205 struct perf_event_header header;
9211 event = event->parent;
9213 rec.header.type = PERF_RECORD_AUX_OUTPUT_HW_ID;
9214 rec.header.misc = 0;
9215 rec.header.size = sizeof(rec);
9218 perf_event_header__init_id(&rec.header, &sample, event);
9219 ret = perf_output_begin(&handle, &sample, event, rec.header.size);
9224 perf_output_put(&handle, rec);
9225 perf_event__output_id_sample(event, &handle, &sample);
9227 perf_output_end(&handle);
9231 __perf_event_account_interrupt(struct perf_event *event, int throttle)
9233 struct hw_perf_event *hwc = &event->hw;
9237 seq = __this_cpu_read(perf_throttled_seq);
9238 if (seq != hwc->interrupts_seq) {
9239 hwc->interrupts_seq = seq;
9240 hwc->interrupts = 1;
9243 if (unlikely(throttle
9244 && hwc->interrupts >= max_samples_per_tick)) {
9245 __this_cpu_inc(perf_throttled_count);
9246 tick_dep_set_cpu(smp_processor_id(), TICK_DEP_BIT_PERF_EVENTS);
9247 hwc->interrupts = MAX_INTERRUPTS;
9248 perf_log_throttle(event, 0);
9253 if (event->attr.freq) {
9254 u64 now = perf_clock();
9255 s64 delta = now - hwc->freq_time_stamp;
9257 hwc->freq_time_stamp = now;
9259 if (delta > 0 && delta < 2*TICK_NSEC)
9260 perf_adjust_period(event, delta, hwc->last_period, true);
9266 int perf_event_account_interrupt(struct perf_event *event)
9268 return __perf_event_account_interrupt(event, 1);
9272 * Generic event overflow handling, sampling.
9275 static int __perf_event_overflow(struct perf_event *event,
9276 int throttle, struct perf_sample_data *data,
9277 struct pt_regs *regs)
9279 int events = atomic_read(&event->event_limit);
9283 * Non-sampling counters might still use the PMI to fold short
9284 * hardware counters, ignore those.
9286 if (unlikely(!is_sampling_event(event)))
9289 ret = __perf_event_account_interrupt(event, throttle);
9292 * XXX event_limit might not quite work as expected on inherited
9296 event->pending_kill = POLL_IN;
9297 if (events && atomic_dec_and_test(&event->event_limit)) {
9299 event->pending_kill = POLL_HUP;
9300 event->pending_addr = data->addr;
9302 perf_event_disable_inatomic(event);
9305 READ_ONCE(event->overflow_handler)(event, data, regs);
9307 if (*perf_event_fasync(event) && event->pending_kill) {
9308 event->pending_wakeup = 1;
9309 irq_work_queue(&event->pending);
9315 int perf_event_overflow(struct perf_event *event,
9316 struct perf_sample_data *data,
9317 struct pt_regs *regs)
9319 return __perf_event_overflow(event, 1, data, regs);
9323 * Generic software event infrastructure
9326 struct swevent_htable {
9327 struct swevent_hlist *swevent_hlist;
9328 struct mutex hlist_mutex;
9331 /* Recursion avoidance in each contexts */
9332 int recursion[PERF_NR_CONTEXTS];
9335 static DEFINE_PER_CPU(struct swevent_htable, swevent_htable);
9338 * We directly increment event->count and keep a second value in
9339 * event->hw.period_left to count intervals. This period event
9340 * is kept in the range [-sample_period, 0] so that we can use the
9344 u64 perf_swevent_set_period(struct perf_event *event)
9346 struct hw_perf_event *hwc = &event->hw;
9347 u64 period = hwc->last_period;
9351 hwc->last_period = hwc->sample_period;
9354 old = val = local64_read(&hwc->period_left);
9358 nr = div64_u64(period + val, period);
9359 offset = nr * period;
9361 if (local64_cmpxchg(&hwc->period_left, old, val) != old)
9367 static void perf_swevent_overflow(struct perf_event *event, u64 overflow,
9368 struct perf_sample_data *data,
9369 struct pt_regs *regs)
9371 struct hw_perf_event *hwc = &event->hw;
9375 overflow = perf_swevent_set_period(event);
9377 if (hwc->interrupts == MAX_INTERRUPTS)
9380 for (; overflow; overflow--) {
9381 if (__perf_event_overflow(event, throttle,
9384 * We inhibit the overflow from happening when
9385 * hwc->interrupts == MAX_INTERRUPTS.
9393 static void perf_swevent_event(struct perf_event *event, u64 nr,
9394 struct perf_sample_data *data,
9395 struct pt_regs *regs)
9397 struct hw_perf_event *hwc = &event->hw;
9399 local64_add(nr, &event->count);
9404 if (!is_sampling_event(event))
9407 if ((event->attr.sample_type & PERF_SAMPLE_PERIOD) && !event->attr.freq) {
9409 return perf_swevent_overflow(event, 1, data, regs);
9411 data->period = event->hw.last_period;
9413 if (nr == 1 && hwc->sample_period == 1 && !event->attr.freq)
9414 return perf_swevent_overflow(event, 1, data, regs);
9416 if (local64_add_negative(nr, &hwc->period_left))
9419 perf_swevent_overflow(event, 0, data, regs);
9422 static int perf_exclude_event(struct perf_event *event,
9423 struct pt_regs *regs)
9425 if (event->hw.state & PERF_HES_STOPPED)
9429 if (event->attr.exclude_user && user_mode(regs))
9432 if (event->attr.exclude_kernel && !user_mode(regs))
9439 static int perf_swevent_match(struct perf_event *event,
9440 enum perf_type_id type,
9442 struct perf_sample_data *data,
9443 struct pt_regs *regs)
9445 if (event->attr.type != type)
9448 if (event->attr.config != event_id)
9451 if (perf_exclude_event(event, regs))
9457 static inline u64 swevent_hash(u64 type, u32 event_id)
9459 u64 val = event_id | (type << 32);
9461 return hash_64(val, SWEVENT_HLIST_BITS);
9464 static inline struct hlist_head *
9465 __find_swevent_head(struct swevent_hlist *hlist, u64 type, u32 event_id)
9467 u64 hash = swevent_hash(type, event_id);
9469 return &hlist->heads[hash];
9472 /* For the read side: events when they trigger */
9473 static inline struct hlist_head *
9474 find_swevent_head_rcu(struct swevent_htable *swhash, u64 type, u32 event_id)
9476 struct swevent_hlist *hlist;
9478 hlist = rcu_dereference(swhash->swevent_hlist);
9482 return __find_swevent_head(hlist, type, event_id);
9485 /* For the event head insertion and removal in the hlist */
9486 static inline struct hlist_head *
9487 find_swevent_head(struct swevent_htable *swhash, struct perf_event *event)
9489 struct swevent_hlist *hlist;
9490 u32 event_id = event->attr.config;
9491 u64 type = event->attr.type;
9494 * Event scheduling is always serialized against hlist allocation
9495 * and release. Which makes the protected version suitable here.
9496 * The context lock guarantees that.
9498 hlist = rcu_dereference_protected(swhash->swevent_hlist,
9499 lockdep_is_held(&event->ctx->lock));
9503 return __find_swevent_head(hlist, type, event_id);
9506 static void do_perf_sw_event(enum perf_type_id type, u32 event_id,
9508 struct perf_sample_data *data,
9509 struct pt_regs *regs)
9511 struct swevent_htable *swhash = this_cpu_ptr(&swevent_htable);
9512 struct perf_event *event;
9513 struct hlist_head *head;
9516 head = find_swevent_head_rcu(swhash, type, event_id);
9520 hlist_for_each_entry_rcu(event, head, hlist_entry) {
9521 if (perf_swevent_match(event, type, event_id, data, regs))
9522 perf_swevent_event(event, nr, data, regs);
9528 DEFINE_PER_CPU(struct pt_regs, __perf_regs[4]);
9530 int perf_swevent_get_recursion_context(void)
9532 struct swevent_htable *swhash = this_cpu_ptr(&swevent_htable);
9534 return get_recursion_context(swhash->recursion);
9536 EXPORT_SYMBOL_GPL(perf_swevent_get_recursion_context);
9538 void perf_swevent_put_recursion_context(int rctx)
9540 struct swevent_htable *swhash = this_cpu_ptr(&swevent_htable);
9542 put_recursion_context(swhash->recursion, rctx);
9545 void ___perf_sw_event(u32 event_id, u64 nr, struct pt_regs *regs, u64 addr)
9547 struct perf_sample_data data;
9549 if (WARN_ON_ONCE(!regs))
9552 perf_sample_data_init(&data, addr, 0);
9553 do_perf_sw_event(PERF_TYPE_SOFTWARE, event_id, nr, &data, regs);
9556 void __perf_sw_event(u32 event_id, u64 nr, struct pt_regs *regs, u64 addr)
9560 preempt_disable_notrace();
9561 rctx = perf_swevent_get_recursion_context();
9562 if (unlikely(rctx < 0))
9565 ___perf_sw_event(event_id, nr, regs, addr);
9567 perf_swevent_put_recursion_context(rctx);
9569 preempt_enable_notrace();
9572 static void perf_swevent_read(struct perf_event *event)
9576 static int perf_swevent_add(struct perf_event *event, int flags)
9578 struct swevent_htable *swhash = this_cpu_ptr(&swevent_htable);
9579 struct hw_perf_event *hwc = &event->hw;
9580 struct hlist_head *head;
9582 if (is_sampling_event(event)) {
9583 hwc->last_period = hwc->sample_period;
9584 perf_swevent_set_period(event);
9587 hwc->state = !(flags & PERF_EF_START);
9589 head = find_swevent_head(swhash, event);
9590 if (WARN_ON_ONCE(!head))
9593 hlist_add_head_rcu(&event->hlist_entry, head);
9594 perf_event_update_userpage(event);
9599 static void perf_swevent_del(struct perf_event *event, int flags)
9601 hlist_del_rcu(&event->hlist_entry);
9604 static void perf_swevent_start(struct perf_event *event, int flags)
9606 event->hw.state = 0;
9609 static void perf_swevent_stop(struct perf_event *event, int flags)
9611 event->hw.state = PERF_HES_STOPPED;
9614 /* Deref the hlist from the update side */
9615 static inline struct swevent_hlist *
9616 swevent_hlist_deref(struct swevent_htable *swhash)
9618 return rcu_dereference_protected(swhash->swevent_hlist,
9619 lockdep_is_held(&swhash->hlist_mutex));
9622 static void swevent_hlist_release(struct swevent_htable *swhash)
9624 struct swevent_hlist *hlist = swevent_hlist_deref(swhash);
9629 RCU_INIT_POINTER(swhash->swevent_hlist, NULL);
9630 kfree_rcu(hlist, rcu_head);
9633 static void swevent_hlist_put_cpu(int cpu)
9635 struct swevent_htable *swhash = &per_cpu(swevent_htable, cpu);
9637 mutex_lock(&swhash->hlist_mutex);
9639 if (!--swhash->hlist_refcount)
9640 swevent_hlist_release(swhash);
9642 mutex_unlock(&swhash->hlist_mutex);
9645 static void swevent_hlist_put(void)
9649 for_each_possible_cpu(cpu)
9650 swevent_hlist_put_cpu(cpu);
9653 static int swevent_hlist_get_cpu(int cpu)
9655 struct swevent_htable *swhash = &per_cpu(swevent_htable, cpu);
9658 mutex_lock(&swhash->hlist_mutex);
9659 if (!swevent_hlist_deref(swhash) &&
9660 cpumask_test_cpu(cpu, perf_online_mask)) {
9661 struct swevent_hlist *hlist;
9663 hlist = kzalloc(sizeof(*hlist), GFP_KERNEL);
9668 rcu_assign_pointer(swhash->swevent_hlist, hlist);
9670 swhash->hlist_refcount++;
9672 mutex_unlock(&swhash->hlist_mutex);
9677 static int swevent_hlist_get(void)
9679 int err, cpu, failed_cpu;
9681 mutex_lock(&pmus_lock);
9682 for_each_possible_cpu(cpu) {
9683 err = swevent_hlist_get_cpu(cpu);
9689 mutex_unlock(&pmus_lock);
9692 for_each_possible_cpu(cpu) {
9693 if (cpu == failed_cpu)
9695 swevent_hlist_put_cpu(cpu);
9697 mutex_unlock(&pmus_lock);
9701 struct static_key perf_swevent_enabled[PERF_COUNT_SW_MAX];
9703 static void sw_perf_event_destroy(struct perf_event *event)
9705 u64 event_id = event->attr.config;
9707 WARN_ON(event->parent);
9709 static_key_slow_dec(&perf_swevent_enabled[event_id]);
9710 swevent_hlist_put();
9713 static int perf_swevent_init(struct perf_event *event)
9715 u64 event_id = event->attr.config;
9717 if (event->attr.type != PERF_TYPE_SOFTWARE)
9721 * no branch sampling for software events
9723 if (has_branch_stack(event))
9727 case PERF_COUNT_SW_CPU_CLOCK:
9728 case PERF_COUNT_SW_TASK_CLOCK:
9735 if (event_id >= PERF_COUNT_SW_MAX)
9738 if (!event->parent) {
9741 err = swevent_hlist_get();
9745 static_key_slow_inc(&perf_swevent_enabled[event_id]);
9746 event->destroy = sw_perf_event_destroy;
9752 static struct pmu perf_swevent = {
9753 .task_ctx_nr = perf_sw_context,
9755 .capabilities = PERF_PMU_CAP_NO_NMI,
9757 .event_init = perf_swevent_init,
9758 .add = perf_swevent_add,
9759 .del = perf_swevent_del,
9760 .start = perf_swevent_start,
9761 .stop = perf_swevent_stop,
9762 .read = perf_swevent_read,
9765 #ifdef CONFIG_EVENT_TRACING
9767 static int perf_tp_filter_match(struct perf_event *event,
9768 struct perf_sample_data *data)
9770 void *record = data->raw->frag.data;
9772 /* only top level events have filters set */
9774 event = event->parent;
9776 if (likely(!event->filter) || filter_match_preds(event->filter, record))
9781 static int perf_tp_event_match(struct perf_event *event,
9782 struct perf_sample_data *data,
9783 struct pt_regs *regs)
9785 if (event->hw.state & PERF_HES_STOPPED)
9788 * If exclude_kernel, only trace user-space tracepoints (uprobes)
9790 if (event->attr.exclude_kernel && !user_mode(regs))
9793 if (!perf_tp_filter_match(event, data))
9799 void perf_trace_run_bpf_submit(void *raw_data, int size, int rctx,
9800 struct trace_event_call *call, u64 count,
9801 struct pt_regs *regs, struct hlist_head *head,
9802 struct task_struct *task)
9804 if (bpf_prog_array_valid(call)) {
9805 *(struct pt_regs **)raw_data = regs;
9806 if (!trace_call_bpf(call, raw_data) || hlist_empty(head)) {
9807 perf_swevent_put_recursion_context(rctx);
9811 perf_tp_event(call->event.type, count, raw_data, size, regs, head,
9814 EXPORT_SYMBOL_GPL(perf_trace_run_bpf_submit);
9816 void perf_tp_event(u16 event_type, u64 count, void *record, int entry_size,
9817 struct pt_regs *regs, struct hlist_head *head, int rctx,
9818 struct task_struct *task)
9820 struct perf_sample_data data;
9821 struct perf_event *event;
9823 struct perf_raw_record raw = {
9830 perf_sample_data_init(&data, 0, 0);
9833 perf_trace_buf_update(record, event_type);
9835 hlist_for_each_entry_rcu(event, head, hlist_entry) {
9836 if (perf_tp_event_match(event, &data, regs))
9837 perf_swevent_event(event, count, &data, regs);
9841 * If we got specified a target task, also iterate its context and
9842 * deliver this event there too.
9844 if (task && task != current) {
9845 struct perf_event_context *ctx;
9846 struct trace_entry *entry = record;
9849 ctx = rcu_dereference(task->perf_event_ctxp[perf_sw_context]);
9853 list_for_each_entry_rcu(event, &ctx->event_list, event_entry) {
9854 if (event->cpu != smp_processor_id())
9856 if (event->attr.type != PERF_TYPE_TRACEPOINT)
9858 if (event->attr.config != entry->type)
9860 /* Cannot deliver synchronous signal to other task. */
9861 if (event->attr.sigtrap)
9863 if (perf_tp_event_match(event, &data, regs))
9864 perf_swevent_event(event, count, &data, regs);
9870 perf_swevent_put_recursion_context(rctx);
9872 EXPORT_SYMBOL_GPL(perf_tp_event);
9874 static void tp_perf_event_destroy(struct perf_event *event)
9876 perf_trace_destroy(event);
9879 static int perf_tp_event_init(struct perf_event *event)
9883 if (event->attr.type != PERF_TYPE_TRACEPOINT)
9887 * no branch sampling for tracepoint events
9889 if (has_branch_stack(event))
9892 err = perf_trace_init(event);
9896 event->destroy = tp_perf_event_destroy;
9901 static struct pmu perf_tracepoint = {
9902 .task_ctx_nr = perf_sw_context,
9904 .event_init = perf_tp_event_init,
9905 .add = perf_trace_add,
9906 .del = perf_trace_del,
9907 .start = perf_swevent_start,
9908 .stop = perf_swevent_stop,
9909 .read = perf_swevent_read,
9912 #if defined(CONFIG_KPROBE_EVENTS) || defined(CONFIG_UPROBE_EVENTS)
9914 * Flags in config, used by dynamic PMU kprobe and uprobe
9915 * The flags should match following PMU_FORMAT_ATTR().
9917 * PERF_PROBE_CONFIG_IS_RETPROBE if set, create kretprobe/uretprobe
9918 * if not set, create kprobe/uprobe
9920 * The following values specify a reference counter (or semaphore in the
9921 * terminology of tools like dtrace, systemtap, etc.) Userspace Statically
9922 * Defined Tracepoints (USDT). Currently, we use 40 bit for the offset.
9924 * PERF_UPROBE_REF_CTR_OFFSET_BITS # of bits in config as th offset
9925 * PERF_UPROBE_REF_CTR_OFFSET_SHIFT # of bits to shift left
9927 enum perf_probe_config {
9928 PERF_PROBE_CONFIG_IS_RETPROBE = 1U << 0, /* [k,u]retprobe */
9929 PERF_UPROBE_REF_CTR_OFFSET_BITS = 32,
9930 PERF_UPROBE_REF_CTR_OFFSET_SHIFT = 64 - PERF_UPROBE_REF_CTR_OFFSET_BITS,
9933 PMU_FORMAT_ATTR(retprobe, "config:0");
9936 #ifdef CONFIG_KPROBE_EVENTS
9937 static struct attribute *kprobe_attrs[] = {
9938 &format_attr_retprobe.attr,
9942 static struct attribute_group kprobe_format_group = {
9944 .attrs = kprobe_attrs,
9947 static const struct attribute_group *kprobe_attr_groups[] = {
9948 &kprobe_format_group,
9952 static int perf_kprobe_event_init(struct perf_event *event);
9953 static struct pmu perf_kprobe = {
9954 .task_ctx_nr = perf_sw_context,
9955 .event_init = perf_kprobe_event_init,
9956 .add = perf_trace_add,
9957 .del = perf_trace_del,
9958 .start = perf_swevent_start,
9959 .stop = perf_swevent_stop,
9960 .read = perf_swevent_read,
9961 .attr_groups = kprobe_attr_groups,
9964 static int perf_kprobe_event_init(struct perf_event *event)
9969 if (event->attr.type != perf_kprobe.type)
9972 if (!perfmon_capable())
9976 * no branch sampling for probe events
9978 if (has_branch_stack(event))
9981 is_retprobe = event->attr.config & PERF_PROBE_CONFIG_IS_RETPROBE;
9982 err = perf_kprobe_init(event, is_retprobe);
9986 event->destroy = perf_kprobe_destroy;
9990 #endif /* CONFIG_KPROBE_EVENTS */
9992 #ifdef CONFIG_UPROBE_EVENTS
9993 PMU_FORMAT_ATTR(ref_ctr_offset, "config:32-63");
9995 static struct attribute *uprobe_attrs[] = {
9996 &format_attr_retprobe.attr,
9997 &format_attr_ref_ctr_offset.attr,
10001 static struct attribute_group uprobe_format_group = {
10003 .attrs = uprobe_attrs,
10006 static const struct attribute_group *uprobe_attr_groups[] = {
10007 &uprobe_format_group,
10011 static int perf_uprobe_event_init(struct perf_event *event);
10012 static struct pmu perf_uprobe = {
10013 .task_ctx_nr = perf_sw_context,
10014 .event_init = perf_uprobe_event_init,
10015 .add = perf_trace_add,
10016 .del = perf_trace_del,
10017 .start = perf_swevent_start,
10018 .stop = perf_swevent_stop,
10019 .read = perf_swevent_read,
10020 .attr_groups = uprobe_attr_groups,
10023 static int perf_uprobe_event_init(struct perf_event *event)
10026 unsigned long ref_ctr_offset;
10029 if (event->attr.type != perf_uprobe.type)
10032 if (!perfmon_capable())
10036 * no branch sampling for probe events
10038 if (has_branch_stack(event))
10039 return -EOPNOTSUPP;
10041 is_retprobe = event->attr.config & PERF_PROBE_CONFIG_IS_RETPROBE;
10042 ref_ctr_offset = event->attr.config >> PERF_UPROBE_REF_CTR_OFFSET_SHIFT;
10043 err = perf_uprobe_init(event, ref_ctr_offset, is_retprobe);
10047 event->destroy = perf_uprobe_destroy;
10051 #endif /* CONFIG_UPROBE_EVENTS */
10053 static inline void perf_tp_register(void)
10055 perf_pmu_register(&perf_tracepoint, "tracepoint", PERF_TYPE_TRACEPOINT);
10056 #ifdef CONFIG_KPROBE_EVENTS
10057 perf_pmu_register(&perf_kprobe, "kprobe", -1);
10059 #ifdef CONFIG_UPROBE_EVENTS
10060 perf_pmu_register(&perf_uprobe, "uprobe", -1);
10064 static void perf_event_free_filter(struct perf_event *event)
10066 ftrace_profile_free_filter(event);
10069 #ifdef CONFIG_BPF_SYSCALL
10070 static void bpf_overflow_handler(struct perf_event *event,
10071 struct perf_sample_data *data,
10072 struct pt_regs *regs)
10074 struct bpf_perf_event_data_kern ctx = {
10078 struct bpf_prog *prog;
10081 ctx.regs = perf_arch_bpf_user_pt_regs(regs);
10082 if (unlikely(__this_cpu_inc_return(bpf_prog_active) != 1))
10085 prog = READ_ONCE(event->prog);
10087 ret = bpf_prog_run(prog, &ctx);
10090 __this_cpu_dec(bpf_prog_active);
10094 event->orig_overflow_handler(event, data, regs);
10097 static int perf_event_set_bpf_handler(struct perf_event *event,
10098 struct bpf_prog *prog,
10101 if (event->overflow_handler_context)
10102 /* hw breakpoint or kernel counter */
10108 if (prog->type != BPF_PROG_TYPE_PERF_EVENT)
10111 if (event->attr.precise_ip &&
10112 prog->call_get_stack &&
10113 (!(event->attr.sample_type & __PERF_SAMPLE_CALLCHAIN_EARLY) ||
10114 event->attr.exclude_callchain_kernel ||
10115 event->attr.exclude_callchain_user)) {
10117 * On perf_event with precise_ip, calling bpf_get_stack()
10118 * may trigger unwinder warnings and occasional crashes.
10119 * bpf_get_[stack|stackid] works around this issue by using
10120 * callchain attached to perf_sample_data. If the
10121 * perf_event does not full (kernel and user) callchain
10122 * attached to perf_sample_data, do not allow attaching BPF
10123 * program that calls bpf_get_[stack|stackid].
10128 event->prog = prog;
10129 event->bpf_cookie = bpf_cookie;
10130 event->orig_overflow_handler = READ_ONCE(event->overflow_handler);
10131 WRITE_ONCE(event->overflow_handler, bpf_overflow_handler);
10135 static void perf_event_free_bpf_handler(struct perf_event *event)
10137 struct bpf_prog *prog = event->prog;
10142 WRITE_ONCE(event->overflow_handler, event->orig_overflow_handler);
10143 event->prog = NULL;
10144 bpf_prog_put(prog);
10147 static int perf_event_set_bpf_handler(struct perf_event *event,
10148 struct bpf_prog *prog,
10151 return -EOPNOTSUPP;
10153 static void perf_event_free_bpf_handler(struct perf_event *event)
10159 * returns true if the event is a tracepoint, or a kprobe/upprobe created
10160 * with perf_event_open()
10162 static inline bool perf_event_is_tracing(struct perf_event *event)
10164 if (event->pmu == &perf_tracepoint)
10166 #ifdef CONFIG_KPROBE_EVENTS
10167 if (event->pmu == &perf_kprobe)
10170 #ifdef CONFIG_UPROBE_EVENTS
10171 if (event->pmu == &perf_uprobe)
10177 int perf_event_set_bpf_prog(struct perf_event *event, struct bpf_prog *prog,
10180 bool is_kprobe, is_tracepoint, is_syscall_tp;
10182 if (!perf_event_is_tracing(event))
10183 return perf_event_set_bpf_handler(event, prog, bpf_cookie);
10185 is_kprobe = event->tp_event->flags & TRACE_EVENT_FL_UKPROBE;
10186 is_tracepoint = event->tp_event->flags & TRACE_EVENT_FL_TRACEPOINT;
10187 is_syscall_tp = is_syscall_trace_event(event->tp_event);
10188 if (!is_kprobe && !is_tracepoint && !is_syscall_tp)
10189 /* bpf programs can only be attached to u/kprobe or tracepoint */
10192 if ((is_kprobe && prog->type != BPF_PROG_TYPE_KPROBE) ||
10193 (is_tracepoint && prog->type != BPF_PROG_TYPE_TRACEPOINT) ||
10194 (is_syscall_tp && prog->type != BPF_PROG_TYPE_TRACEPOINT))
10197 /* Kprobe override only works for kprobes, not uprobes. */
10198 if (prog->kprobe_override &&
10199 !(event->tp_event->flags & TRACE_EVENT_FL_KPROBE))
10202 if (is_tracepoint || is_syscall_tp) {
10203 int off = trace_event_get_offsets(event->tp_event);
10205 if (prog->aux->max_ctx_offset > off)
10209 return perf_event_attach_bpf_prog(event, prog, bpf_cookie);
10212 void perf_event_free_bpf_prog(struct perf_event *event)
10214 if (!perf_event_is_tracing(event)) {
10215 perf_event_free_bpf_handler(event);
10218 perf_event_detach_bpf_prog(event);
10223 static inline void perf_tp_register(void)
10227 static void perf_event_free_filter(struct perf_event *event)
10231 int perf_event_set_bpf_prog(struct perf_event *event, struct bpf_prog *prog,
10237 void perf_event_free_bpf_prog(struct perf_event *event)
10240 #endif /* CONFIG_EVENT_TRACING */
10242 #ifdef CONFIG_HAVE_HW_BREAKPOINT
10243 void perf_bp_event(struct perf_event *bp, void *data)
10245 struct perf_sample_data sample;
10246 struct pt_regs *regs = data;
10248 perf_sample_data_init(&sample, bp->attr.bp_addr, 0);
10250 if (!bp->hw.state && !perf_exclude_event(bp, regs))
10251 perf_swevent_event(bp, 1, &sample, regs);
10256 * Allocate a new address filter
10258 static struct perf_addr_filter *
10259 perf_addr_filter_new(struct perf_event *event, struct list_head *filters)
10261 int node = cpu_to_node(event->cpu == -1 ? 0 : event->cpu);
10262 struct perf_addr_filter *filter;
10264 filter = kzalloc_node(sizeof(*filter), GFP_KERNEL, node);
10268 INIT_LIST_HEAD(&filter->entry);
10269 list_add_tail(&filter->entry, filters);
10274 static void free_filters_list(struct list_head *filters)
10276 struct perf_addr_filter *filter, *iter;
10278 list_for_each_entry_safe(filter, iter, filters, entry) {
10279 path_put(&filter->path);
10280 list_del(&filter->entry);
10286 * Free existing address filters and optionally install new ones
10288 static void perf_addr_filters_splice(struct perf_event *event,
10289 struct list_head *head)
10291 unsigned long flags;
10294 if (!has_addr_filter(event))
10297 /* don't bother with children, they don't have their own filters */
10301 raw_spin_lock_irqsave(&event->addr_filters.lock, flags);
10303 list_splice_init(&event->addr_filters.list, &list);
10305 list_splice(head, &event->addr_filters.list);
10307 raw_spin_unlock_irqrestore(&event->addr_filters.lock, flags);
10309 free_filters_list(&list);
10313 * Scan through mm's vmas and see if one of them matches the
10314 * @filter; if so, adjust filter's address range.
10315 * Called with mm::mmap_lock down for reading.
10317 static void perf_addr_filter_apply(struct perf_addr_filter *filter,
10318 struct mm_struct *mm,
10319 struct perf_addr_filter_range *fr)
10321 struct vm_area_struct *vma;
10323 for (vma = mm->mmap; vma; vma = vma->vm_next) {
10327 if (perf_addr_filter_vma_adjust(filter, vma, fr))
10333 * Update event's address range filters based on the
10334 * task's existing mappings, if any.
10336 static void perf_event_addr_filters_apply(struct perf_event *event)
10338 struct perf_addr_filters_head *ifh = perf_event_addr_filters(event);
10339 struct task_struct *task = READ_ONCE(event->ctx->task);
10340 struct perf_addr_filter *filter;
10341 struct mm_struct *mm = NULL;
10342 unsigned int count = 0;
10343 unsigned long flags;
10346 * We may observe TASK_TOMBSTONE, which means that the event tear-down
10347 * will stop on the parent's child_mutex that our caller is also holding
10349 if (task == TASK_TOMBSTONE)
10352 if (ifh->nr_file_filters) {
10353 mm = get_task_mm(task);
10357 mmap_read_lock(mm);
10360 raw_spin_lock_irqsave(&ifh->lock, flags);
10361 list_for_each_entry(filter, &ifh->list, entry) {
10362 if (filter->path.dentry) {
10364 * Adjust base offset if the filter is associated to a
10365 * binary that needs to be mapped:
10367 event->addr_filter_ranges[count].start = 0;
10368 event->addr_filter_ranges[count].size = 0;
10370 perf_addr_filter_apply(filter, mm, &event->addr_filter_ranges[count]);
10372 event->addr_filter_ranges[count].start = filter->offset;
10373 event->addr_filter_ranges[count].size = filter->size;
10379 event->addr_filters_gen++;
10380 raw_spin_unlock_irqrestore(&ifh->lock, flags);
10382 if (ifh->nr_file_filters) {
10383 mmap_read_unlock(mm);
10389 perf_event_stop(event, 1);
10393 * Address range filtering: limiting the data to certain
10394 * instruction address ranges. Filters are ioctl()ed to us from
10395 * userspace as ascii strings.
10397 * Filter string format:
10399 * ACTION RANGE_SPEC
10400 * where ACTION is one of the
10401 * * "filter": limit the trace to this region
10402 * * "start": start tracing from this address
10403 * * "stop": stop tracing at this address/region;
10405 * * for kernel addresses: <start address>[/<size>]
10406 * * for object files: <start address>[/<size>]@</path/to/object/file>
10408 * if <size> is not specified or is zero, the range is treated as a single
10409 * address; not valid for ACTION=="filter".
10423 IF_STATE_ACTION = 0,
10428 static const match_table_t if_tokens = {
10429 { IF_ACT_FILTER, "filter" },
10430 { IF_ACT_START, "start" },
10431 { IF_ACT_STOP, "stop" },
10432 { IF_SRC_FILE, "%u/%u@%s" },
10433 { IF_SRC_KERNEL, "%u/%u" },
10434 { IF_SRC_FILEADDR, "%u@%s" },
10435 { IF_SRC_KERNELADDR, "%u" },
10436 { IF_ACT_NONE, NULL },
10440 * Address filter string parser
10443 perf_event_parse_addr_filter(struct perf_event *event, char *fstr,
10444 struct list_head *filters)
10446 struct perf_addr_filter *filter = NULL;
10447 char *start, *orig, *filename = NULL;
10448 substring_t args[MAX_OPT_ARGS];
10449 int state = IF_STATE_ACTION, token;
10450 unsigned int kernel = 0;
10453 orig = fstr = kstrdup(fstr, GFP_KERNEL);
10457 while ((start = strsep(&fstr, " ,\n")) != NULL) {
10458 static const enum perf_addr_filter_action_t actions[] = {
10459 [IF_ACT_FILTER] = PERF_ADDR_FILTER_ACTION_FILTER,
10460 [IF_ACT_START] = PERF_ADDR_FILTER_ACTION_START,
10461 [IF_ACT_STOP] = PERF_ADDR_FILTER_ACTION_STOP,
10468 /* filter definition begins */
10469 if (state == IF_STATE_ACTION) {
10470 filter = perf_addr_filter_new(event, filters);
10475 token = match_token(start, if_tokens, args);
10477 case IF_ACT_FILTER:
10480 if (state != IF_STATE_ACTION)
10483 filter->action = actions[token];
10484 state = IF_STATE_SOURCE;
10487 case IF_SRC_KERNELADDR:
10488 case IF_SRC_KERNEL:
10492 case IF_SRC_FILEADDR:
10494 if (state != IF_STATE_SOURCE)
10498 ret = kstrtoul(args[0].from, 0, &filter->offset);
10502 if (token == IF_SRC_KERNEL || token == IF_SRC_FILE) {
10504 ret = kstrtoul(args[1].from, 0, &filter->size);
10509 if (token == IF_SRC_FILE || token == IF_SRC_FILEADDR) {
10510 int fpos = token == IF_SRC_FILE ? 2 : 1;
10513 filename = match_strdup(&args[fpos]);
10520 state = IF_STATE_END;
10528 * Filter definition is fully parsed, validate and install it.
10529 * Make sure that it doesn't contradict itself or the event's
10532 if (state == IF_STATE_END) {
10534 if (kernel && event->attr.exclude_kernel)
10538 * ACTION "filter" must have a non-zero length region
10541 if (filter->action == PERF_ADDR_FILTER_ACTION_FILTER &&
10550 * For now, we only support file-based filters
10551 * in per-task events; doing so for CPU-wide
10552 * events requires additional context switching
10553 * trickery, since same object code will be
10554 * mapped at different virtual addresses in
10555 * different processes.
10558 if (!event->ctx->task)
10561 /* look up the path and grab its inode */
10562 ret = kern_path(filename, LOOKUP_FOLLOW,
10568 if (!filter->path.dentry ||
10569 !S_ISREG(d_inode(filter->path.dentry)
10573 event->addr_filters.nr_file_filters++;
10576 /* ready to consume more filters */
10577 state = IF_STATE_ACTION;
10582 if (state != IF_STATE_ACTION)
10592 free_filters_list(filters);
10599 perf_event_set_addr_filter(struct perf_event *event, char *filter_str)
10601 LIST_HEAD(filters);
10605 * Since this is called in perf_ioctl() path, we're already holding
10608 lockdep_assert_held(&event->ctx->mutex);
10610 if (WARN_ON_ONCE(event->parent))
10613 ret = perf_event_parse_addr_filter(event, filter_str, &filters);
10615 goto fail_clear_files;
10617 ret = event->pmu->addr_filters_validate(&filters);
10619 goto fail_free_filters;
10621 /* remove existing filters, if any */
10622 perf_addr_filters_splice(event, &filters);
10624 /* install new filters */
10625 perf_event_for_each_child(event, perf_event_addr_filters_apply);
10630 free_filters_list(&filters);
10633 event->addr_filters.nr_file_filters = 0;
10638 static int perf_event_set_filter(struct perf_event *event, void __user *arg)
10643 filter_str = strndup_user(arg, PAGE_SIZE);
10644 if (IS_ERR(filter_str))
10645 return PTR_ERR(filter_str);
10647 #ifdef CONFIG_EVENT_TRACING
10648 if (perf_event_is_tracing(event)) {
10649 struct perf_event_context *ctx = event->ctx;
10652 * Beware, here be dragons!!
10654 * the tracepoint muck will deadlock against ctx->mutex, but
10655 * the tracepoint stuff does not actually need it. So
10656 * temporarily drop ctx->mutex. As per perf_event_ctx_lock() we
10657 * already have a reference on ctx.
10659 * This can result in event getting moved to a different ctx,
10660 * but that does not affect the tracepoint state.
10662 mutex_unlock(&ctx->mutex);
10663 ret = ftrace_profile_set_filter(event, event->attr.config, filter_str);
10664 mutex_lock(&ctx->mutex);
10667 if (has_addr_filter(event))
10668 ret = perf_event_set_addr_filter(event, filter_str);
10675 * hrtimer based swevent callback
10678 static enum hrtimer_restart perf_swevent_hrtimer(struct hrtimer *hrtimer)
10680 enum hrtimer_restart ret = HRTIMER_RESTART;
10681 struct perf_sample_data data;
10682 struct pt_regs *regs;
10683 struct perf_event *event;
10686 event = container_of(hrtimer, struct perf_event, hw.hrtimer);
10688 if (event->state != PERF_EVENT_STATE_ACTIVE)
10689 return HRTIMER_NORESTART;
10691 event->pmu->read(event);
10693 perf_sample_data_init(&data, 0, event->hw.last_period);
10694 regs = get_irq_regs();
10696 if (regs && !perf_exclude_event(event, regs)) {
10697 if (!(event->attr.exclude_idle && is_idle_task(current)))
10698 if (__perf_event_overflow(event, 1, &data, regs))
10699 ret = HRTIMER_NORESTART;
10702 period = max_t(u64, 10000, event->hw.sample_period);
10703 hrtimer_forward_now(hrtimer, ns_to_ktime(period));
10708 static void perf_swevent_start_hrtimer(struct perf_event *event)
10710 struct hw_perf_event *hwc = &event->hw;
10713 if (!is_sampling_event(event))
10716 period = local64_read(&hwc->period_left);
10721 local64_set(&hwc->period_left, 0);
10723 period = max_t(u64, 10000, hwc->sample_period);
10725 hrtimer_start(&hwc->hrtimer, ns_to_ktime(period),
10726 HRTIMER_MODE_REL_PINNED_HARD);
10729 static void perf_swevent_cancel_hrtimer(struct perf_event *event)
10731 struct hw_perf_event *hwc = &event->hw;
10733 if (is_sampling_event(event)) {
10734 ktime_t remaining = hrtimer_get_remaining(&hwc->hrtimer);
10735 local64_set(&hwc->period_left, ktime_to_ns(remaining));
10737 hrtimer_cancel(&hwc->hrtimer);
10741 static void perf_swevent_init_hrtimer(struct perf_event *event)
10743 struct hw_perf_event *hwc = &event->hw;
10745 if (!is_sampling_event(event))
10748 hrtimer_init(&hwc->hrtimer, CLOCK_MONOTONIC, HRTIMER_MODE_REL_HARD);
10749 hwc->hrtimer.function = perf_swevent_hrtimer;
10752 * Since hrtimers have a fixed rate, we can do a static freq->period
10753 * mapping and avoid the whole period adjust feedback stuff.
10755 if (event->attr.freq) {
10756 long freq = event->attr.sample_freq;
10758 event->attr.sample_period = NSEC_PER_SEC / freq;
10759 hwc->sample_period = event->attr.sample_period;
10760 local64_set(&hwc->period_left, hwc->sample_period);
10761 hwc->last_period = hwc->sample_period;
10762 event->attr.freq = 0;
10767 * Software event: cpu wall time clock
10770 static void cpu_clock_event_update(struct perf_event *event)
10775 now = local_clock();
10776 prev = local64_xchg(&event->hw.prev_count, now);
10777 local64_add(now - prev, &event->count);
10780 static void cpu_clock_event_start(struct perf_event *event, int flags)
10782 local64_set(&event->hw.prev_count, local_clock());
10783 perf_swevent_start_hrtimer(event);
10786 static void cpu_clock_event_stop(struct perf_event *event, int flags)
10788 perf_swevent_cancel_hrtimer(event);
10789 cpu_clock_event_update(event);
10792 static int cpu_clock_event_add(struct perf_event *event, int flags)
10794 if (flags & PERF_EF_START)
10795 cpu_clock_event_start(event, flags);
10796 perf_event_update_userpage(event);
10801 static void cpu_clock_event_del(struct perf_event *event, int flags)
10803 cpu_clock_event_stop(event, flags);
10806 static void cpu_clock_event_read(struct perf_event *event)
10808 cpu_clock_event_update(event);
10811 static int cpu_clock_event_init(struct perf_event *event)
10813 if (event->attr.type != PERF_TYPE_SOFTWARE)
10816 if (event->attr.config != PERF_COUNT_SW_CPU_CLOCK)
10820 * no branch sampling for software events
10822 if (has_branch_stack(event))
10823 return -EOPNOTSUPP;
10825 perf_swevent_init_hrtimer(event);
10830 static struct pmu perf_cpu_clock = {
10831 .task_ctx_nr = perf_sw_context,
10833 .capabilities = PERF_PMU_CAP_NO_NMI,
10835 .event_init = cpu_clock_event_init,
10836 .add = cpu_clock_event_add,
10837 .del = cpu_clock_event_del,
10838 .start = cpu_clock_event_start,
10839 .stop = cpu_clock_event_stop,
10840 .read = cpu_clock_event_read,
10844 * Software event: task time clock
10847 static void task_clock_event_update(struct perf_event *event, u64 now)
10852 prev = local64_xchg(&event->hw.prev_count, now);
10853 delta = now - prev;
10854 local64_add(delta, &event->count);
10857 static void task_clock_event_start(struct perf_event *event, int flags)
10859 local64_set(&event->hw.prev_count, event->ctx->time);
10860 perf_swevent_start_hrtimer(event);
10863 static void task_clock_event_stop(struct perf_event *event, int flags)
10865 perf_swevent_cancel_hrtimer(event);
10866 task_clock_event_update(event, event->ctx->time);
10869 static int task_clock_event_add(struct perf_event *event, int flags)
10871 if (flags & PERF_EF_START)
10872 task_clock_event_start(event, flags);
10873 perf_event_update_userpage(event);
10878 static void task_clock_event_del(struct perf_event *event, int flags)
10880 task_clock_event_stop(event, PERF_EF_UPDATE);
10883 static void task_clock_event_read(struct perf_event *event)
10885 u64 now = perf_clock();
10886 u64 delta = now - event->ctx->timestamp;
10887 u64 time = event->ctx->time + delta;
10889 task_clock_event_update(event, time);
10892 static int task_clock_event_init(struct perf_event *event)
10894 if (event->attr.type != PERF_TYPE_SOFTWARE)
10897 if (event->attr.config != PERF_COUNT_SW_TASK_CLOCK)
10901 * no branch sampling for software events
10903 if (has_branch_stack(event))
10904 return -EOPNOTSUPP;
10906 perf_swevent_init_hrtimer(event);
10911 static struct pmu perf_task_clock = {
10912 .task_ctx_nr = perf_sw_context,
10914 .capabilities = PERF_PMU_CAP_NO_NMI,
10916 .event_init = task_clock_event_init,
10917 .add = task_clock_event_add,
10918 .del = task_clock_event_del,
10919 .start = task_clock_event_start,
10920 .stop = task_clock_event_stop,
10921 .read = task_clock_event_read,
10924 static void perf_pmu_nop_void(struct pmu *pmu)
10928 static void perf_pmu_nop_txn(struct pmu *pmu, unsigned int flags)
10932 static int perf_pmu_nop_int(struct pmu *pmu)
10937 static int perf_event_nop_int(struct perf_event *event, u64 value)
10942 static DEFINE_PER_CPU(unsigned int, nop_txn_flags);
10944 static void perf_pmu_start_txn(struct pmu *pmu, unsigned int flags)
10946 __this_cpu_write(nop_txn_flags, flags);
10948 if (flags & ~PERF_PMU_TXN_ADD)
10951 perf_pmu_disable(pmu);
10954 static int perf_pmu_commit_txn(struct pmu *pmu)
10956 unsigned int flags = __this_cpu_read(nop_txn_flags);
10958 __this_cpu_write(nop_txn_flags, 0);
10960 if (flags & ~PERF_PMU_TXN_ADD)
10963 perf_pmu_enable(pmu);
10967 static void perf_pmu_cancel_txn(struct pmu *pmu)
10969 unsigned int flags = __this_cpu_read(nop_txn_flags);
10971 __this_cpu_write(nop_txn_flags, 0);
10973 if (flags & ~PERF_PMU_TXN_ADD)
10976 perf_pmu_enable(pmu);
10979 static int perf_event_idx_default(struct perf_event *event)
10985 * Ensures all contexts with the same task_ctx_nr have the same
10986 * pmu_cpu_context too.
10988 static struct perf_cpu_context __percpu *find_pmu_context(int ctxn)
10995 list_for_each_entry(pmu, &pmus, entry) {
10996 if (pmu->task_ctx_nr == ctxn)
10997 return pmu->pmu_cpu_context;
11003 static void free_pmu_context(struct pmu *pmu)
11006 * Static contexts such as perf_sw_context have a global lifetime
11007 * and may be shared between different PMUs. Avoid freeing them
11008 * when a single PMU is going away.
11010 if (pmu->task_ctx_nr > perf_invalid_context)
11013 free_percpu(pmu->pmu_cpu_context);
11017 * Let userspace know that this PMU supports address range filtering:
11019 static ssize_t nr_addr_filters_show(struct device *dev,
11020 struct device_attribute *attr,
11023 struct pmu *pmu = dev_get_drvdata(dev);
11025 return snprintf(page, PAGE_SIZE - 1, "%d\n", pmu->nr_addr_filters);
11027 DEVICE_ATTR_RO(nr_addr_filters);
11029 static struct idr pmu_idr;
11032 type_show(struct device *dev, struct device_attribute *attr, char *page)
11034 struct pmu *pmu = dev_get_drvdata(dev);
11036 return snprintf(page, PAGE_SIZE-1, "%d\n", pmu->type);
11038 static DEVICE_ATTR_RO(type);
11041 perf_event_mux_interval_ms_show(struct device *dev,
11042 struct device_attribute *attr,
11045 struct pmu *pmu = dev_get_drvdata(dev);
11047 return snprintf(page, PAGE_SIZE-1, "%d\n", pmu->hrtimer_interval_ms);
11050 static DEFINE_MUTEX(mux_interval_mutex);
11053 perf_event_mux_interval_ms_store(struct device *dev,
11054 struct device_attribute *attr,
11055 const char *buf, size_t count)
11057 struct pmu *pmu = dev_get_drvdata(dev);
11058 int timer, cpu, ret;
11060 ret = kstrtoint(buf, 0, &timer);
11067 /* same value, noting to do */
11068 if (timer == pmu->hrtimer_interval_ms)
11071 mutex_lock(&mux_interval_mutex);
11072 pmu->hrtimer_interval_ms = timer;
11074 /* update all cpuctx for this PMU */
11076 for_each_online_cpu(cpu) {
11077 struct perf_cpu_context *cpuctx;
11078 cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
11079 cpuctx->hrtimer_interval = ns_to_ktime(NSEC_PER_MSEC * timer);
11081 cpu_function_call(cpu,
11082 (remote_function_f)perf_mux_hrtimer_restart, cpuctx);
11084 cpus_read_unlock();
11085 mutex_unlock(&mux_interval_mutex);
11089 static DEVICE_ATTR_RW(perf_event_mux_interval_ms);
11091 static struct attribute *pmu_dev_attrs[] = {
11092 &dev_attr_type.attr,
11093 &dev_attr_perf_event_mux_interval_ms.attr,
11096 ATTRIBUTE_GROUPS(pmu_dev);
11098 static int pmu_bus_running;
11099 static struct bus_type pmu_bus = {
11100 .name = "event_source",
11101 .dev_groups = pmu_dev_groups,
11104 static void pmu_dev_release(struct device *dev)
11109 static int pmu_dev_alloc(struct pmu *pmu)
11113 pmu->dev = kzalloc(sizeof(struct device), GFP_KERNEL);
11117 pmu->dev->groups = pmu->attr_groups;
11118 device_initialize(pmu->dev);
11119 ret = dev_set_name(pmu->dev, "%s", pmu->name);
11123 dev_set_drvdata(pmu->dev, pmu);
11124 pmu->dev->bus = &pmu_bus;
11125 pmu->dev->release = pmu_dev_release;
11126 ret = device_add(pmu->dev);
11130 /* For PMUs with address filters, throw in an extra attribute: */
11131 if (pmu->nr_addr_filters)
11132 ret = device_create_file(pmu->dev, &dev_attr_nr_addr_filters);
11137 if (pmu->attr_update)
11138 ret = sysfs_update_groups(&pmu->dev->kobj, pmu->attr_update);
11147 device_del(pmu->dev);
11150 put_device(pmu->dev);
11154 static struct lock_class_key cpuctx_mutex;
11155 static struct lock_class_key cpuctx_lock;
11157 int perf_pmu_register(struct pmu *pmu, const char *name, int type)
11159 int cpu, ret, max = PERF_TYPE_MAX;
11161 mutex_lock(&pmus_lock);
11163 pmu->pmu_disable_count = alloc_percpu(int);
11164 if (!pmu->pmu_disable_count)
11172 if (type != PERF_TYPE_SOFTWARE) {
11176 ret = idr_alloc(&pmu_idr, pmu, max, 0, GFP_KERNEL);
11180 WARN_ON(type >= 0 && ret != type);
11186 if (pmu_bus_running) {
11187 ret = pmu_dev_alloc(pmu);
11193 if (pmu->task_ctx_nr == perf_hw_context) {
11194 static int hw_context_taken = 0;
11197 * Other than systems with heterogeneous CPUs, it never makes
11198 * sense for two PMUs to share perf_hw_context. PMUs which are
11199 * uncore must use perf_invalid_context.
11201 if (WARN_ON_ONCE(hw_context_taken &&
11202 !(pmu->capabilities & PERF_PMU_CAP_HETEROGENEOUS_CPUS)))
11203 pmu->task_ctx_nr = perf_invalid_context;
11205 hw_context_taken = 1;
11208 pmu->pmu_cpu_context = find_pmu_context(pmu->task_ctx_nr);
11209 if (pmu->pmu_cpu_context)
11210 goto got_cpu_context;
11213 pmu->pmu_cpu_context = alloc_percpu(struct perf_cpu_context);
11214 if (!pmu->pmu_cpu_context)
11217 for_each_possible_cpu(cpu) {
11218 struct perf_cpu_context *cpuctx;
11220 cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
11221 __perf_event_init_context(&cpuctx->ctx);
11222 lockdep_set_class(&cpuctx->ctx.mutex, &cpuctx_mutex);
11223 lockdep_set_class(&cpuctx->ctx.lock, &cpuctx_lock);
11224 cpuctx->ctx.pmu = pmu;
11225 cpuctx->online = cpumask_test_cpu(cpu, perf_online_mask);
11227 __perf_mux_hrtimer_init(cpuctx, cpu);
11229 cpuctx->heap_size = ARRAY_SIZE(cpuctx->heap_default);
11230 cpuctx->heap = cpuctx->heap_default;
11234 if (!pmu->start_txn) {
11235 if (pmu->pmu_enable) {
11237 * If we have pmu_enable/pmu_disable calls, install
11238 * transaction stubs that use that to try and batch
11239 * hardware accesses.
11241 pmu->start_txn = perf_pmu_start_txn;
11242 pmu->commit_txn = perf_pmu_commit_txn;
11243 pmu->cancel_txn = perf_pmu_cancel_txn;
11245 pmu->start_txn = perf_pmu_nop_txn;
11246 pmu->commit_txn = perf_pmu_nop_int;
11247 pmu->cancel_txn = perf_pmu_nop_void;
11251 if (!pmu->pmu_enable) {
11252 pmu->pmu_enable = perf_pmu_nop_void;
11253 pmu->pmu_disable = perf_pmu_nop_void;
11256 if (!pmu->check_period)
11257 pmu->check_period = perf_event_nop_int;
11259 if (!pmu->event_idx)
11260 pmu->event_idx = perf_event_idx_default;
11263 * Ensure the TYPE_SOFTWARE PMUs are at the head of the list,
11264 * since these cannot be in the IDR. This way the linear search
11265 * is fast, provided a valid software event is provided.
11267 if (type == PERF_TYPE_SOFTWARE || !name)
11268 list_add_rcu(&pmu->entry, &pmus);
11270 list_add_tail_rcu(&pmu->entry, &pmus);
11272 atomic_set(&pmu->exclusive_cnt, 0);
11275 mutex_unlock(&pmus_lock);
11280 device_del(pmu->dev);
11281 put_device(pmu->dev);
11284 if (pmu->type != PERF_TYPE_SOFTWARE)
11285 idr_remove(&pmu_idr, pmu->type);
11288 free_percpu(pmu->pmu_disable_count);
11291 EXPORT_SYMBOL_GPL(perf_pmu_register);
11293 void perf_pmu_unregister(struct pmu *pmu)
11295 mutex_lock(&pmus_lock);
11296 list_del_rcu(&pmu->entry);
11299 * We dereference the pmu list under both SRCU and regular RCU, so
11300 * synchronize against both of those.
11302 synchronize_srcu(&pmus_srcu);
11305 free_percpu(pmu->pmu_disable_count);
11306 if (pmu->type != PERF_TYPE_SOFTWARE)
11307 idr_remove(&pmu_idr, pmu->type);
11308 if (pmu_bus_running) {
11309 if (pmu->nr_addr_filters)
11310 device_remove_file(pmu->dev, &dev_attr_nr_addr_filters);
11311 device_del(pmu->dev);
11312 put_device(pmu->dev);
11314 free_pmu_context(pmu);
11315 mutex_unlock(&pmus_lock);
11317 EXPORT_SYMBOL_GPL(perf_pmu_unregister);
11319 static inline bool has_extended_regs(struct perf_event *event)
11321 return (event->attr.sample_regs_user & PERF_REG_EXTENDED_MASK) ||
11322 (event->attr.sample_regs_intr & PERF_REG_EXTENDED_MASK);
11325 static int perf_try_init_event(struct pmu *pmu, struct perf_event *event)
11327 struct perf_event_context *ctx = NULL;
11330 if (!try_module_get(pmu->module))
11334 * A number of pmu->event_init() methods iterate the sibling_list to,
11335 * for example, validate if the group fits on the PMU. Therefore,
11336 * if this is a sibling event, acquire the ctx->mutex to protect
11337 * the sibling_list.
11339 if (event->group_leader != event && pmu->task_ctx_nr != perf_sw_context) {
11341 * This ctx->mutex can nest when we're called through
11342 * inheritance. See the perf_event_ctx_lock_nested() comment.
11344 ctx = perf_event_ctx_lock_nested(event->group_leader,
11345 SINGLE_DEPTH_NESTING);
11350 ret = pmu->event_init(event);
11353 perf_event_ctx_unlock(event->group_leader, ctx);
11356 if (!(pmu->capabilities & PERF_PMU_CAP_EXTENDED_REGS) &&
11357 has_extended_regs(event))
11360 if (pmu->capabilities & PERF_PMU_CAP_NO_EXCLUDE &&
11361 event_has_any_exclude_flag(event))
11364 if (ret && event->destroy)
11365 event->destroy(event);
11369 module_put(pmu->module);
11374 static struct pmu *perf_init_event(struct perf_event *event)
11376 bool extended_type = false;
11377 int idx, type, ret;
11380 idx = srcu_read_lock(&pmus_srcu);
11382 /* Try parent's PMU first: */
11383 if (event->parent && event->parent->pmu) {
11384 pmu = event->parent->pmu;
11385 ret = perf_try_init_event(pmu, event);
11391 * PERF_TYPE_HARDWARE and PERF_TYPE_HW_CACHE
11392 * are often aliases for PERF_TYPE_RAW.
11394 type = event->attr.type;
11395 if (type == PERF_TYPE_HARDWARE || type == PERF_TYPE_HW_CACHE) {
11396 type = event->attr.config >> PERF_PMU_TYPE_SHIFT;
11398 type = PERF_TYPE_RAW;
11400 extended_type = true;
11401 event->attr.config &= PERF_HW_EVENT_MASK;
11407 pmu = idr_find(&pmu_idr, type);
11410 if (event->attr.type != type && type != PERF_TYPE_RAW &&
11411 !(pmu->capabilities & PERF_PMU_CAP_EXTENDED_HW_TYPE))
11414 ret = perf_try_init_event(pmu, event);
11415 if (ret == -ENOENT && event->attr.type != type && !extended_type) {
11416 type = event->attr.type;
11421 pmu = ERR_PTR(ret);
11426 list_for_each_entry_rcu(pmu, &pmus, entry, lockdep_is_held(&pmus_srcu)) {
11427 ret = perf_try_init_event(pmu, event);
11431 if (ret != -ENOENT) {
11432 pmu = ERR_PTR(ret);
11437 pmu = ERR_PTR(-ENOENT);
11439 srcu_read_unlock(&pmus_srcu, idx);
11444 static void attach_sb_event(struct perf_event *event)
11446 struct pmu_event_list *pel = per_cpu_ptr(&pmu_sb_events, event->cpu);
11448 raw_spin_lock(&pel->lock);
11449 list_add_rcu(&event->sb_list, &pel->list);
11450 raw_spin_unlock(&pel->lock);
11454 * We keep a list of all !task (and therefore per-cpu) events
11455 * that need to receive side-band records.
11457 * This avoids having to scan all the various PMU per-cpu contexts
11458 * looking for them.
11460 static void account_pmu_sb_event(struct perf_event *event)
11462 if (is_sb_event(event))
11463 attach_sb_event(event);
11466 static void account_event_cpu(struct perf_event *event, int cpu)
11471 if (is_cgroup_event(event))
11472 atomic_inc(&per_cpu(perf_cgroup_events, cpu));
11475 /* Freq events need the tick to stay alive (see perf_event_task_tick). */
11476 static void account_freq_event_nohz(void)
11478 #ifdef CONFIG_NO_HZ_FULL
11479 /* Lock so we don't race with concurrent unaccount */
11480 spin_lock(&nr_freq_lock);
11481 if (atomic_inc_return(&nr_freq_events) == 1)
11482 tick_nohz_dep_set(TICK_DEP_BIT_PERF_EVENTS);
11483 spin_unlock(&nr_freq_lock);
11487 static void account_freq_event(void)
11489 if (tick_nohz_full_enabled())
11490 account_freq_event_nohz();
11492 atomic_inc(&nr_freq_events);
11496 static void account_event(struct perf_event *event)
11503 if (event->attach_state & (PERF_ATTACH_TASK | PERF_ATTACH_SCHED_CB))
11505 if (event->attr.mmap || event->attr.mmap_data)
11506 atomic_inc(&nr_mmap_events);
11507 if (event->attr.build_id)
11508 atomic_inc(&nr_build_id_events);
11509 if (event->attr.comm)
11510 atomic_inc(&nr_comm_events);
11511 if (event->attr.namespaces)
11512 atomic_inc(&nr_namespaces_events);
11513 if (event->attr.cgroup)
11514 atomic_inc(&nr_cgroup_events);
11515 if (event->attr.task)
11516 atomic_inc(&nr_task_events);
11517 if (event->attr.freq)
11518 account_freq_event();
11519 if (event->attr.context_switch) {
11520 atomic_inc(&nr_switch_events);
11523 if (has_branch_stack(event))
11525 if (is_cgroup_event(event))
11527 if (event->attr.ksymbol)
11528 atomic_inc(&nr_ksymbol_events);
11529 if (event->attr.bpf_event)
11530 atomic_inc(&nr_bpf_events);
11531 if (event->attr.text_poke)
11532 atomic_inc(&nr_text_poke_events);
11536 * We need the mutex here because static_branch_enable()
11537 * must complete *before* the perf_sched_count increment
11540 if (atomic_inc_not_zero(&perf_sched_count))
11543 mutex_lock(&perf_sched_mutex);
11544 if (!atomic_read(&perf_sched_count)) {
11545 static_branch_enable(&perf_sched_events);
11547 * Guarantee that all CPUs observe they key change and
11548 * call the perf scheduling hooks before proceeding to
11549 * install events that need them.
11554 * Now that we have waited for the sync_sched(), allow further
11555 * increments to by-pass the mutex.
11557 atomic_inc(&perf_sched_count);
11558 mutex_unlock(&perf_sched_mutex);
11562 account_event_cpu(event, event->cpu);
11564 account_pmu_sb_event(event);
11568 * Allocate and initialize an event structure
11570 static struct perf_event *
11571 perf_event_alloc(struct perf_event_attr *attr, int cpu,
11572 struct task_struct *task,
11573 struct perf_event *group_leader,
11574 struct perf_event *parent_event,
11575 perf_overflow_handler_t overflow_handler,
11576 void *context, int cgroup_fd)
11579 struct perf_event *event;
11580 struct hw_perf_event *hwc;
11581 long err = -EINVAL;
11584 if ((unsigned)cpu >= nr_cpu_ids) {
11585 if (!task || cpu != -1)
11586 return ERR_PTR(-EINVAL);
11588 if (attr->sigtrap && !task) {
11589 /* Requires a task: avoid signalling random tasks. */
11590 return ERR_PTR(-EINVAL);
11593 node = (cpu >= 0) ? cpu_to_node(cpu) : -1;
11594 event = kmem_cache_alloc_node(perf_event_cache, GFP_KERNEL | __GFP_ZERO,
11597 return ERR_PTR(-ENOMEM);
11600 * Single events are their own group leaders, with an
11601 * empty sibling list:
11604 group_leader = event;
11606 mutex_init(&event->child_mutex);
11607 INIT_LIST_HEAD(&event->child_list);
11609 INIT_LIST_HEAD(&event->event_entry);
11610 INIT_LIST_HEAD(&event->sibling_list);
11611 INIT_LIST_HEAD(&event->active_list);
11612 init_event_group(event);
11613 INIT_LIST_HEAD(&event->rb_entry);
11614 INIT_LIST_HEAD(&event->active_entry);
11615 INIT_LIST_HEAD(&event->addr_filters.list);
11616 INIT_HLIST_NODE(&event->hlist_entry);
11619 init_waitqueue_head(&event->waitq);
11620 event->pending_disable = -1;
11621 init_irq_work(&event->pending, perf_pending_event);
11623 mutex_init(&event->mmap_mutex);
11624 raw_spin_lock_init(&event->addr_filters.lock);
11626 atomic_long_set(&event->refcount, 1);
11628 event->attr = *attr;
11629 event->group_leader = group_leader;
11633 event->parent = parent_event;
11635 event->ns = get_pid_ns(task_active_pid_ns(current));
11636 event->id = atomic64_inc_return(&perf_event_id);
11638 event->state = PERF_EVENT_STATE_INACTIVE;
11640 if (event->attr.sigtrap)
11641 atomic_set(&event->event_limit, 1);
11644 event->attach_state = PERF_ATTACH_TASK;
11646 * XXX pmu::event_init needs to know what task to account to
11647 * and we cannot use the ctx information because we need the
11648 * pmu before we get a ctx.
11650 event->hw.target = get_task_struct(task);
11653 event->clock = &local_clock;
11655 event->clock = parent_event->clock;
11657 if (!overflow_handler && parent_event) {
11658 overflow_handler = parent_event->overflow_handler;
11659 context = parent_event->overflow_handler_context;
11660 #if defined(CONFIG_BPF_SYSCALL) && defined(CONFIG_EVENT_TRACING)
11661 if (overflow_handler == bpf_overflow_handler) {
11662 struct bpf_prog *prog = parent_event->prog;
11664 bpf_prog_inc(prog);
11665 event->prog = prog;
11666 event->orig_overflow_handler =
11667 parent_event->orig_overflow_handler;
11672 if (overflow_handler) {
11673 event->overflow_handler = overflow_handler;
11674 event->overflow_handler_context = context;
11675 } else if (is_write_backward(event)){
11676 event->overflow_handler = perf_event_output_backward;
11677 event->overflow_handler_context = NULL;
11679 event->overflow_handler = perf_event_output_forward;
11680 event->overflow_handler_context = NULL;
11683 perf_event__state_init(event);
11688 hwc->sample_period = attr->sample_period;
11689 if (attr->freq && attr->sample_freq)
11690 hwc->sample_period = 1;
11691 hwc->last_period = hwc->sample_period;
11693 local64_set(&hwc->period_left, hwc->sample_period);
11696 * We currently do not support PERF_SAMPLE_READ on inherited events.
11697 * See perf_output_read().
11699 if (attr->inherit && (attr->sample_type & PERF_SAMPLE_READ))
11702 if (!has_branch_stack(event))
11703 event->attr.branch_sample_type = 0;
11705 pmu = perf_init_event(event);
11707 err = PTR_ERR(pmu);
11712 * Disallow uncore-cgroup events, they don't make sense as the cgroup will
11713 * be different on other CPUs in the uncore mask.
11715 if (pmu->task_ctx_nr == perf_invalid_context && cgroup_fd != -1) {
11720 if (event->attr.aux_output &&
11721 !(pmu->capabilities & PERF_PMU_CAP_AUX_OUTPUT)) {
11726 if (cgroup_fd != -1) {
11727 err = perf_cgroup_connect(cgroup_fd, event, attr, group_leader);
11732 err = exclusive_event_init(event);
11736 if (has_addr_filter(event)) {
11737 event->addr_filter_ranges = kcalloc(pmu->nr_addr_filters,
11738 sizeof(struct perf_addr_filter_range),
11740 if (!event->addr_filter_ranges) {
11746 * Clone the parent's vma offsets: they are valid until exec()
11747 * even if the mm is not shared with the parent.
11749 if (event->parent) {
11750 struct perf_addr_filters_head *ifh = perf_event_addr_filters(event);
11752 raw_spin_lock_irq(&ifh->lock);
11753 memcpy(event->addr_filter_ranges,
11754 event->parent->addr_filter_ranges,
11755 pmu->nr_addr_filters * sizeof(struct perf_addr_filter_range));
11756 raw_spin_unlock_irq(&ifh->lock);
11759 /* force hw sync on the address filters */
11760 event->addr_filters_gen = 1;
11763 if (!event->parent) {
11764 if (event->attr.sample_type & PERF_SAMPLE_CALLCHAIN) {
11765 err = get_callchain_buffers(attr->sample_max_stack);
11767 goto err_addr_filters;
11771 err = security_perf_event_alloc(event);
11773 goto err_callchain_buffer;
11775 /* symmetric to unaccount_event() in _free_event() */
11776 account_event(event);
11780 err_callchain_buffer:
11781 if (!event->parent) {
11782 if (event->attr.sample_type & PERF_SAMPLE_CALLCHAIN)
11783 put_callchain_buffers();
11786 kfree(event->addr_filter_ranges);
11789 exclusive_event_destroy(event);
11792 if (is_cgroup_event(event))
11793 perf_detach_cgroup(event);
11794 if (event->destroy)
11795 event->destroy(event);
11796 module_put(pmu->module);
11799 put_pid_ns(event->ns);
11800 if (event->hw.target)
11801 put_task_struct(event->hw.target);
11802 kmem_cache_free(perf_event_cache, event);
11804 return ERR_PTR(err);
11807 static int perf_copy_attr(struct perf_event_attr __user *uattr,
11808 struct perf_event_attr *attr)
11813 /* Zero the full structure, so that a short copy will be nice. */
11814 memset(attr, 0, sizeof(*attr));
11816 ret = get_user(size, &uattr->size);
11820 /* ABI compatibility quirk: */
11822 size = PERF_ATTR_SIZE_VER0;
11823 if (size < PERF_ATTR_SIZE_VER0 || size > PAGE_SIZE)
11826 ret = copy_struct_from_user(attr, sizeof(*attr), uattr, size);
11835 if (attr->__reserved_1 || attr->__reserved_2 || attr->__reserved_3)
11838 if (attr->sample_type & ~(PERF_SAMPLE_MAX-1))
11841 if (attr->read_format & ~(PERF_FORMAT_MAX-1))
11844 if (attr->sample_type & PERF_SAMPLE_BRANCH_STACK) {
11845 u64 mask = attr->branch_sample_type;
11847 /* only using defined bits */
11848 if (mask & ~(PERF_SAMPLE_BRANCH_MAX-1))
11851 /* at least one branch bit must be set */
11852 if (!(mask & ~PERF_SAMPLE_BRANCH_PLM_ALL))
11855 /* propagate priv level, when not set for branch */
11856 if (!(mask & PERF_SAMPLE_BRANCH_PLM_ALL)) {
11858 /* exclude_kernel checked on syscall entry */
11859 if (!attr->exclude_kernel)
11860 mask |= PERF_SAMPLE_BRANCH_KERNEL;
11862 if (!attr->exclude_user)
11863 mask |= PERF_SAMPLE_BRANCH_USER;
11865 if (!attr->exclude_hv)
11866 mask |= PERF_SAMPLE_BRANCH_HV;
11868 * adjust user setting (for HW filter setup)
11870 attr->branch_sample_type = mask;
11872 /* privileged levels capture (kernel, hv): check permissions */
11873 if (mask & PERF_SAMPLE_BRANCH_PERM_PLM) {
11874 ret = perf_allow_kernel(attr);
11880 if (attr->sample_type & PERF_SAMPLE_REGS_USER) {
11881 ret = perf_reg_validate(attr->sample_regs_user);
11886 if (attr->sample_type & PERF_SAMPLE_STACK_USER) {
11887 if (!arch_perf_have_user_stack_dump())
11891 * We have __u32 type for the size, but so far
11892 * we can only use __u16 as maximum due to the
11893 * __u16 sample size limit.
11895 if (attr->sample_stack_user >= USHRT_MAX)
11897 else if (!IS_ALIGNED(attr->sample_stack_user, sizeof(u64)))
11901 if (!attr->sample_max_stack)
11902 attr->sample_max_stack = sysctl_perf_event_max_stack;
11904 if (attr->sample_type & PERF_SAMPLE_REGS_INTR)
11905 ret = perf_reg_validate(attr->sample_regs_intr);
11907 #ifndef CONFIG_CGROUP_PERF
11908 if (attr->sample_type & PERF_SAMPLE_CGROUP)
11911 if ((attr->sample_type & PERF_SAMPLE_WEIGHT) &&
11912 (attr->sample_type & PERF_SAMPLE_WEIGHT_STRUCT))
11915 if (!attr->inherit && attr->inherit_thread)
11918 if (attr->remove_on_exec && attr->enable_on_exec)
11921 if (attr->sigtrap && !attr->remove_on_exec)
11928 put_user(sizeof(*attr), &uattr->size);
11934 perf_event_set_output(struct perf_event *event, struct perf_event *output_event)
11936 struct perf_buffer *rb = NULL;
11942 /* don't allow circular references */
11943 if (event == output_event)
11947 * Don't allow cross-cpu buffers
11949 if (output_event->cpu != event->cpu)
11953 * If its not a per-cpu rb, it must be the same task.
11955 if (output_event->cpu == -1 && output_event->ctx != event->ctx)
11959 * Mixing clocks in the same buffer is trouble you don't need.
11961 if (output_event->clock != event->clock)
11965 * Either writing ring buffer from beginning or from end.
11966 * Mixing is not allowed.
11968 if (is_write_backward(output_event) != is_write_backward(event))
11972 * If both events generate aux data, they must be on the same PMU
11974 if (has_aux(event) && has_aux(output_event) &&
11975 event->pmu != output_event->pmu)
11979 mutex_lock(&event->mmap_mutex);
11980 /* Can't redirect output if we've got an active mmap() */
11981 if (atomic_read(&event->mmap_count))
11984 if (output_event) {
11985 /* get the rb we want to redirect to */
11986 rb = ring_buffer_get(output_event);
11991 ring_buffer_attach(event, rb);
11995 mutex_unlock(&event->mmap_mutex);
12001 static void mutex_lock_double(struct mutex *a, struct mutex *b)
12007 mutex_lock_nested(b, SINGLE_DEPTH_NESTING);
12010 static int perf_event_set_clock(struct perf_event *event, clockid_t clk_id)
12012 bool nmi_safe = false;
12015 case CLOCK_MONOTONIC:
12016 event->clock = &ktime_get_mono_fast_ns;
12020 case CLOCK_MONOTONIC_RAW:
12021 event->clock = &ktime_get_raw_fast_ns;
12025 case CLOCK_REALTIME:
12026 event->clock = &ktime_get_real_ns;
12029 case CLOCK_BOOTTIME:
12030 event->clock = &ktime_get_boottime_ns;
12034 event->clock = &ktime_get_clocktai_ns;
12041 if (!nmi_safe && !(event->pmu->capabilities & PERF_PMU_CAP_NO_NMI))
12048 * Variation on perf_event_ctx_lock_nested(), except we take two context
12051 static struct perf_event_context *
12052 __perf_event_ctx_lock_double(struct perf_event *group_leader,
12053 struct perf_event_context *ctx)
12055 struct perf_event_context *gctx;
12059 gctx = READ_ONCE(group_leader->ctx);
12060 if (!refcount_inc_not_zero(&gctx->refcount)) {
12066 mutex_lock_double(&gctx->mutex, &ctx->mutex);
12068 if (group_leader->ctx != gctx) {
12069 mutex_unlock(&ctx->mutex);
12070 mutex_unlock(&gctx->mutex);
12079 perf_check_permission(struct perf_event_attr *attr, struct task_struct *task)
12081 unsigned int ptrace_mode = PTRACE_MODE_READ_REALCREDS;
12082 bool is_capable = perfmon_capable();
12084 if (attr->sigtrap) {
12086 * perf_event_attr::sigtrap sends signals to the other task.
12087 * Require the current task to also have CAP_KILL.
12090 is_capable &= ns_capable(__task_cred(task)->user_ns, CAP_KILL);
12094 * If the required capabilities aren't available, checks for
12095 * ptrace permissions: upgrade to ATTACH, since sending signals
12096 * can effectively change the target task.
12098 ptrace_mode = PTRACE_MODE_ATTACH_REALCREDS;
12102 * Preserve ptrace permission check for backwards compatibility. The
12103 * ptrace check also includes checks that the current task and other
12104 * task have matching uids, and is therefore not done here explicitly.
12106 return is_capable || ptrace_may_access(task, ptrace_mode);
12110 * sys_perf_event_open - open a performance event, associate it to a task/cpu
12112 * @attr_uptr: event_id type attributes for monitoring/sampling
12115 * @group_fd: group leader event fd
12116 * @flags: perf event open flags
12118 SYSCALL_DEFINE5(perf_event_open,
12119 struct perf_event_attr __user *, attr_uptr,
12120 pid_t, pid, int, cpu, int, group_fd, unsigned long, flags)
12122 struct perf_event *group_leader = NULL, *output_event = NULL;
12123 struct perf_event *event, *sibling;
12124 struct perf_event_attr attr;
12125 struct perf_event_context *ctx, *gctx;
12126 struct file *event_file = NULL;
12127 struct fd group = {NULL, 0};
12128 struct task_struct *task = NULL;
12131 int move_group = 0;
12133 int f_flags = O_RDWR;
12134 int cgroup_fd = -1;
12136 /* for future expandability... */
12137 if (flags & ~PERF_FLAG_ALL)
12140 /* Do we allow access to perf_event_open(2) ? */
12141 err = security_perf_event_open(&attr, PERF_SECURITY_OPEN);
12145 err = perf_copy_attr(attr_uptr, &attr);
12149 if (!attr.exclude_kernel) {
12150 err = perf_allow_kernel(&attr);
12155 if (attr.namespaces) {
12156 if (!perfmon_capable())
12161 if (attr.sample_freq > sysctl_perf_event_sample_rate)
12164 if (attr.sample_period & (1ULL << 63))
12168 /* Only privileged users can get physical addresses */
12169 if ((attr.sample_type & PERF_SAMPLE_PHYS_ADDR)) {
12170 err = perf_allow_kernel(&attr);
12175 /* REGS_INTR can leak data, lockdown must prevent this */
12176 if (attr.sample_type & PERF_SAMPLE_REGS_INTR) {
12177 err = security_locked_down(LOCKDOWN_PERF);
12183 * In cgroup mode, the pid argument is used to pass the fd
12184 * opened to the cgroup directory in cgroupfs. The cpu argument
12185 * designates the cpu on which to monitor threads from that
12188 if ((flags & PERF_FLAG_PID_CGROUP) && (pid == -1 || cpu == -1))
12191 if (flags & PERF_FLAG_FD_CLOEXEC)
12192 f_flags |= O_CLOEXEC;
12194 event_fd = get_unused_fd_flags(f_flags);
12198 if (group_fd != -1) {
12199 err = perf_fget_light(group_fd, &group);
12202 group_leader = group.file->private_data;
12203 if (flags & PERF_FLAG_FD_OUTPUT)
12204 output_event = group_leader;
12205 if (flags & PERF_FLAG_FD_NO_GROUP)
12206 group_leader = NULL;
12209 if (pid != -1 && !(flags & PERF_FLAG_PID_CGROUP)) {
12210 task = find_lively_task_by_vpid(pid);
12211 if (IS_ERR(task)) {
12212 err = PTR_ERR(task);
12217 if (task && group_leader &&
12218 group_leader->attr.inherit != attr.inherit) {
12223 if (flags & PERF_FLAG_PID_CGROUP)
12226 event = perf_event_alloc(&attr, cpu, task, group_leader, NULL,
12227 NULL, NULL, cgroup_fd);
12228 if (IS_ERR(event)) {
12229 err = PTR_ERR(event);
12233 if (is_sampling_event(event)) {
12234 if (event->pmu->capabilities & PERF_PMU_CAP_NO_INTERRUPT) {
12241 * Special case software events and allow them to be part of
12242 * any hardware group.
12246 if (attr.use_clockid) {
12247 err = perf_event_set_clock(event, attr.clockid);
12252 if (pmu->task_ctx_nr == perf_sw_context)
12253 event->event_caps |= PERF_EV_CAP_SOFTWARE;
12255 if (group_leader) {
12256 if (is_software_event(event) &&
12257 !in_software_context(group_leader)) {
12259 * If the event is a sw event, but the group_leader
12260 * is on hw context.
12262 * Allow the addition of software events to hw
12263 * groups, this is safe because software events
12264 * never fail to schedule.
12266 pmu = group_leader->ctx->pmu;
12267 } else if (!is_software_event(event) &&
12268 is_software_event(group_leader) &&
12269 (group_leader->group_caps & PERF_EV_CAP_SOFTWARE)) {
12271 * In case the group is a pure software group, and we
12272 * try to add a hardware event, move the whole group to
12273 * the hardware context.
12280 * Get the target context (task or percpu):
12282 ctx = find_get_context(pmu, task, event);
12284 err = PTR_ERR(ctx);
12289 * Look up the group leader (we will attach this event to it):
12291 if (group_leader) {
12295 * Do not allow a recursive hierarchy (this new sibling
12296 * becoming part of another group-sibling):
12298 if (group_leader->group_leader != group_leader)
12301 /* All events in a group should have the same clock */
12302 if (group_leader->clock != event->clock)
12306 * Make sure we're both events for the same CPU;
12307 * grouping events for different CPUs is broken; since
12308 * you can never concurrently schedule them anyhow.
12310 if (group_leader->cpu != event->cpu)
12314 * Make sure we're both on the same task, or both
12317 if (group_leader->ctx->task != ctx->task)
12321 * Do not allow to attach to a group in a different task
12322 * or CPU context. If we're moving SW events, we'll fix
12323 * this up later, so allow that.
12325 if (!move_group && group_leader->ctx != ctx)
12329 * Only a group leader can be exclusive or pinned
12331 if (attr.exclusive || attr.pinned)
12335 if (output_event) {
12336 err = perf_event_set_output(event, output_event);
12341 event_file = anon_inode_getfile("[perf_event]", &perf_fops, event,
12343 if (IS_ERR(event_file)) {
12344 err = PTR_ERR(event_file);
12350 err = down_read_interruptible(&task->signal->exec_update_lock);
12355 * We must hold exec_update_lock across this and any potential
12356 * perf_install_in_context() call for this new event to
12357 * serialize against exec() altering our credentials (and the
12358 * perf_event_exit_task() that could imply).
12361 if (!perf_check_permission(&attr, task))
12366 gctx = __perf_event_ctx_lock_double(group_leader, ctx);
12368 if (gctx->task == TASK_TOMBSTONE) {
12374 * Check if we raced against another sys_perf_event_open() call
12375 * moving the software group underneath us.
12377 if (!(group_leader->group_caps & PERF_EV_CAP_SOFTWARE)) {
12379 * If someone moved the group out from under us, check
12380 * if this new event wound up on the same ctx, if so
12381 * its the regular !move_group case, otherwise fail.
12387 perf_event_ctx_unlock(group_leader, gctx);
12393 * Failure to create exclusive events returns -EBUSY.
12396 if (!exclusive_event_installable(group_leader, ctx))
12399 for_each_sibling_event(sibling, group_leader) {
12400 if (!exclusive_event_installable(sibling, ctx))
12404 mutex_lock(&ctx->mutex);
12407 if (ctx->task == TASK_TOMBSTONE) {
12412 if (!perf_event_validate_size(event)) {
12419 * Check if the @cpu we're creating an event for is online.
12421 * We use the perf_cpu_context::ctx::mutex to serialize against
12422 * the hotplug notifiers. See perf_event_{init,exit}_cpu().
12424 struct perf_cpu_context *cpuctx =
12425 container_of(ctx, struct perf_cpu_context, ctx);
12427 if (!cpuctx->online) {
12433 if (perf_need_aux_event(event) && !perf_get_aux_event(event, group_leader)) {
12439 * Must be under the same ctx::mutex as perf_install_in_context(),
12440 * because we need to serialize with concurrent event creation.
12442 if (!exclusive_event_installable(event, ctx)) {
12447 WARN_ON_ONCE(ctx->parent_ctx);
12450 * This is the point on no return; we cannot fail hereafter. This is
12451 * where we start modifying current state.
12456 * See perf_event_ctx_lock() for comments on the details
12457 * of swizzling perf_event::ctx.
12459 perf_remove_from_context(group_leader, 0);
12462 for_each_sibling_event(sibling, group_leader) {
12463 perf_remove_from_context(sibling, 0);
12468 * Wait for everybody to stop referencing the events through
12469 * the old lists, before installing it on new lists.
12474 * Install the group siblings before the group leader.
12476 * Because a group leader will try and install the entire group
12477 * (through the sibling list, which is still in-tact), we can
12478 * end up with siblings installed in the wrong context.
12480 * By installing siblings first we NO-OP because they're not
12481 * reachable through the group lists.
12483 for_each_sibling_event(sibling, group_leader) {
12484 perf_event__state_init(sibling);
12485 perf_install_in_context(ctx, sibling, sibling->cpu);
12490 * Removing from the context ends up with disabled
12491 * event. What we want here is event in the initial
12492 * startup state, ready to be add into new context.
12494 perf_event__state_init(group_leader);
12495 perf_install_in_context(ctx, group_leader, group_leader->cpu);
12500 * Precalculate sample_data sizes; do while holding ctx::mutex such
12501 * that we're serialized against further additions and before
12502 * perf_install_in_context() which is the point the event is active and
12503 * can use these values.
12505 perf_event__header_size(event);
12506 perf_event__id_header_size(event);
12508 event->owner = current;
12510 perf_install_in_context(ctx, event, event->cpu);
12511 perf_unpin_context(ctx);
12514 perf_event_ctx_unlock(group_leader, gctx);
12515 mutex_unlock(&ctx->mutex);
12518 up_read(&task->signal->exec_update_lock);
12519 put_task_struct(task);
12522 mutex_lock(¤t->perf_event_mutex);
12523 list_add_tail(&event->owner_entry, ¤t->perf_event_list);
12524 mutex_unlock(¤t->perf_event_mutex);
12527 * Drop the reference on the group_event after placing the
12528 * new event on the sibling_list. This ensures destruction
12529 * of the group leader will find the pointer to itself in
12530 * perf_group_detach().
12533 fd_install(event_fd, event_file);
12538 perf_event_ctx_unlock(group_leader, gctx);
12539 mutex_unlock(&ctx->mutex);
12542 up_read(&task->signal->exec_update_lock);
12546 perf_unpin_context(ctx);
12550 * If event_file is set, the fput() above will have called ->release()
12551 * and that will take care of freeing the event.
12557 put_task_struct(task);
12561 put_unused_fd(event_fd);
12566 * perf_event_create_kernel_counter
12568 * @attr: attributes of the counter to create
12569 * @cpu: cpu in which the counter is bound
12570 * @task: task to profile (NULL for percpu)
12571 * @overflow_handler: callback to trigger when we hit the event
12572 * @context: context data could be used in overflow_handler callback
12574 struct perf_event *
12575 perf_event_create_kernel_counter(struct perf_event_attr *attr, int cpu,
12576 struct task_struct *task,
12577 perf_overflow_handler_t overflow_handler,
12580 struct perf_event_context *ctx;
12581 struct perf_event *event;
12585 * Grouping is not supported for kernel events, neither is 'AUX',
12586 * make sure the caller's intentions are adjusted.
12588 if (attr->aux_output)
12589 return ERR_PTR(-EINVAL);
12591 event = perf_event_alloc(attr, cpu, task, NULL, NULL,
12592 overflow_handler, context, -1);
12593 if (IS_ERR(event)) {
12594 err = PTR_ERR(event);
12598 /* Mark owner so we could distinguish it from user events. */
12599 event->owner = TASK_TOMBSTONE;
12602 * Get the target context (task or percpu):
12604 ctx = find_get_context(event->pmu, task, event);
12606 err = PTR_ERR(ctx);
12610 WARN_ON_ONCE(ctx->parent_ctx);
12611 mutex_lock(&ctx->mutex);
12612 if (ctx->task == TASK_TOMBSTONE) {
12619 * Check if the @cpu we're creating an event for is online.
12621 * We use the perf_cpu_context::ctx::mutex to serialize against
12622 * the hotplug notifiers. See perf_event_{init,exit}_cpu().
12624 struct perf_cpu_context *cpuctx =
12625 container_of(ctx, struct perf_cpu_context, ctx);
12626 if (!cpuctx->online) {
12632 if (!exclusive_event_installable(event, ctx)) {
12637 perf_install_in_context(ctx, event, event->cpu);
12638 perf_unpin_context(ctx);
12639 mutex_unlock(&ctx->mutex);
12644 mutex_unlock(&ctx->mutex);
12645 perf_unpin_context(ctx);
12650 return ERR_PTR(err);
12652 EXPORT_SYMBOL_GPL(perf_event_create_kernel_counter);
12654 void perf_pmu_migrate_context(struct pmu *pmu, int src_cpu, int dst_cpu)
12656 struct perf_event_context *src_ctx;
12657 struct perf_event_context *dst_ctx;
12658 struct perf_event *event, *tmp;
12661 src_ctx = &per_cpu_ptr(pmu->pmu_cpu_context, src_cpu)->ctx;
12662 dst_ctx = &per_cpu_ptr(pmu->pmu_cpu_context, dst_cpu)->ctx;
12665 * See perf_event_ctx_lock() for comments on the details
12666 * of swizzling perf_event::ctx.
12668 mutex_lock_double(&src_ctx->mutex, &dst_ctx->mutex);
12669 list_for_each_entry_safe(event, tmp, &src_ctx->event_list,
12671 perf_remove_from_context(event, 0);
12672 unaccount_event_cpu(event, src_cpu);
12674 list_add(&event->migrate_entry, &events);
12678 * Wait for the events to quiesce before re-instating them.
12683 * Re-instate events in 2 passes.
12685 * Skip over group leaders and only install siblings on this first
12686 * pass, siblings will not get enabled without a leader, however a
12687 * leader will enable its siblings, even if those are still on the old
12690 list_for_each_entry_safe(event, tmp, &events, migrate_entry) {
12691 if (event->group_leader == event)
12694 list_del(&event->migrate_entry);
12695 if (event->state >= PERF_EVENT_STATE_OFF)
12696 event->state = PERF_EVENT_STATE_INACTIVE;
12697 account_event_cpu(event, dst_cpu);
12698 perf_install_in_context(dst_ctx, event, dst_cpu);
12703 * Once all the siblings are setup properly, install the group leaders
12706 list_for_each_entry_safe(event, tmp, &events, migrate_entry) {
12707 list_del(&event->migrate_entry);
12708 if (event->state >= PERF_EVENT_STATE_OFF)
12709 event->state = PERF_EVENT_STATE_INACTIVE;
12710 account_event_cpu(event, dst_cpu);
12711 perf_install_in_context(dst_ctx, event, dst_cpu);
12714 mutex_unlock(&dst_ctx->mutex);
12715 mutex_unlock(&src_ctx->mutex);
12717 EXPORT_SYMBOL_GPL(perf_pmu_migrate_context);
12719 static void sync_child_event(struct perf_event *child_event)
12721 struct perf_event *parent_event = child_event->parent;
12724 if (child_event->attr.inherit_stat) {
12725 struct task_struct *task = child_event->ctx->task;
12727 if (task && task != TASK_TOMBSTONE)
12728 perf_event_read_event(child_event, task);
12731 child_val = perf_event_count(child_event);
12734 * Add back the child's count to the parent's count:
12736 atomic64_add(child_val, &parent_event->child_count);
12737 atomic64_add(child_event->total_time_enabled,
12738 &parent_event->child_total_time_enabled);
12739 atomic64_add(child_event->total_time_running,
12740 &parent_event->child_total_time_running);
12744 perf_event_exit_event(struct perf_event *event, struct perf_event_context *ctx)
12746 struct perf_event *parent_event = event->parent;
12747 unsigned long detach_flags = 0;
12749 if (parent_event) {
12751 * Do not destroy the 'original' grouping; because of the
12752 * context switch optimization the original events could've
12753 * ended up in a random child task.
12755 * If we were to destroy the original group, all group related
12756 * operations would cease to function properly after this
12757 * random child dies.
12759 * Do destroy all inherited groups, we don't care about those
12760 * and being thorough is better.
12762 detach_flags = DETACH_GROUP | DETACH_CHILD;
12763 mutex_lock(&parent_event->child_mutex);
12766 perf_remove_from_context(event, detach_flags);
12768 raw_spin_lock_irq(&ctx->lock);
12769 if (event->state > PERF_EVENT_STATE_EXIT)
12770 perf_event_set_state(event, PERF_EVENT_STATE_EXIT);
12771 raw_spin_unlock_irq(&ctx->lock);
12774 * Child events can be freed.
12776 if (parent_event) {
12777 mutex_unlock(&parent_event->child_mutex);
12779 * Kick perf_poll() for is_event_hup();
12781 perf_event_wakeup(parent_event);
12783 put_event(parent_event);
12788 * Parent events are governed by their filedesc, retain them.
12790 perf_event_wakeup(event);
12793 static void perf_event_exit_task_context(struct task_struct *child, int ctxn)
12795 struct perf_event_context *child_ctx, *clone_ctx = NULL;
12796 struct perf_event *child_event, *next;
12798 WARN_ON_ONCE(child != current);
12800 child_ctx = perf_pin_task_context(child, ctxn);
12805 * In order to reduce the amount of tricky in ctx tear-down, we hold
12806 * ctx::mutex over the entire thing. This serializes against almost
12807 * everything that wants to access the ctx.
12809 * The exception is sys_perf_event_open() /
12810 * perf_event_create_kernel_count() which does find_get_context()
12811 * without ctx::mutex (it cannot because of the move_group double mutex
12812 * lock thing). See the comments in perf_install_in_context().
12814 mutex_lock(&child_ctx->mutex);
12817 * In a single ctx::lock section, de-schedule the events and detach the
12818 * context from the task such that we cannot ever get it scheduled back
12821 raw_spin_lock_irq(&child_ctx->lock);
12822 task_ctx_sched_out(__get_cpu_context(child_ctx), child_ctx, EVENT_ALL);
12825 * Now that the context is inactive, destroy the task <-> ctx relation
12826 * and mark the context dead.
12828 RCU_INIT_POINTER(child->perf_event_ctxp[ctxn], NULL);
12829 put_ctx(child_ctx); /* cannot be last */
12830 WRITE_ONCE(child_ctx->task, TASK_TOMBSTONE);
12831 put_task_struct(current); /* cannot be last */
12833 clone_ctx = unclone_ctx(child_ctx);
12834 raw_spin_unlock_irq(&child_ctx->lock);
12837 put_ctx(clone_ctx);
12840 * Report the task dead after unscheduling the events so that we
12841 * won't get any samples after PERF_RECORD_EXIT. We can however still
12842 * get a few PERF_RECORD_READ events.
12844 perf_event_task(child, child_ctx, 0);
12846 list_for_each_entry_safe(child_event, next, &child_ctx->event_list, event_entry)
12847 perf_event_exit_event(child_event, child_ctx);
12849 mutex_unlock(&child_ctx->mutex);
12851 put_ctx(child_ctx);
12855 * When a child task exits, feed back event values to parent events.
12857 * Can be called with exec_update_lock held when called from
12858 * setup_new_exec().
12860 void perf_event_exit_task(struct task_struct *child)
12862 struct perf_event *event, *tmp;
12865 mutex_lock(&child->perf_event_mutex);
12866 list_for_each_entry_safe(event, tmp, &child->perf_event_list,
12868 list_del_init(&event->owner_entry);
12871 * Ensure the list deletion is visible before we clear
12872 * the owner, closes a race against perf_release() where
12873 * we need to serialize on the owner->perf_event_mutex.
12875 smp_store_release(&event->owner, NULL);
12877 mutex_unlock(&child->perf_event_mutex);
12879 for_each_task_context_nr(ctxn)
12880 perf_event_exit_task_context(child, ctxn);
12883 * The perf_event_exit_task_context calls perf_event_task
12884 * with child's task_ctx, which generates EXIT events for
12885 * child contexts and sets child->perf_event_ctxp[] to NULL.
12886 * At this point we need to send EXIT events to cpu contexts.
12888 perf_event_task(child, NULL, 0);
12891 static void perf_free_event(struct perf_event *event,
12892 struct perf_event_context *ctx)
12894 struct perf_event *parent = event->parent;
12896 if (WARN_ON_ONCE(!parent))
12899 mutex_lock(&parent->child_mutex);
12900 list_del_init(&event->child_list);
12901 mutex_unlock(&parent->child_mutex);
12905 raw_spin_lock_irq(&ctx->lock);
12906 perf_group_detach(event);
12907 list_del_event(event, ctx);
12908 raw_spin_unlock_irq(&ctx->lock);
12913 * Free a context as created by inheritance by perf_event_init_task() below,
12914 * used by fork() in case of fail.
12916 * Even though the task has never lived, the context and events have been
12917 * exposed through the child_list, so we must take care tearing it all down.
12919 void perf_event_free_task(struct task_struct *task)
12921 struct perf_event_context *ctx;
12922 struct perf_event *event, *tmp;
12925 for_each_task_context_nr(ctxn) {
12926 ctx = task->perf_event_ctxp[ctxn];
12930 mutex_lock(&ctx->mutex);
12931 raw_spin_lock_irq(&ctx->lock);
12933 * Destroy the task <-> ctx relation and mark the context dead.
12935 * This is important because even though the task hasn't been
12936 * exposed yet the context has been (through child_list).
12938 RCU_INIT_POINTER(task->perf_event_ctxp[ctxn], NULL);
12939 WRITE_ONCE(ctx->task, TASK_TOMBSTONE);
12940 put_task_struct(task); /* cannot be last */
12941 raw_spin_unlock_irq(&ctx->lock);
12943 list_for_each_entry_safe(event, tmp, &ctx->event_list, event_entry)
12944 perf_free_event(event, ctx);
12946 mutex_unlock(&ctx->mutex);
12949 * perf_event_release_kernel() could've stolen some of our
12950 * child events and still have them on its free_list. In that
12951 * case we must wait for these events to have been freed (in
12952 * particular all their references to this task must've been
12955 * Without this copy_process() will unconditionally free this
12956 * task (irrespective of its reference count) and
12957 * _free_event()'s put_task_struct(event->hw.target) will be a
12960 * Wait for all events to drop their context reference.
12962 wait_var_event(&ctx->refcount, refcount_read(&ctx->refcount) == 1);
12963 put_ctx(ctx); /* must be last */
12967 void perf_event_delayed_put(struct task_struct *task)
12971 for_each_task_context_nr(ctxn)
12972 WARN_ON_ONCE(task->perf_event_ctxp[ctxn]);
12975 struct file *perf_event_get(unsigned int fd)
12977 struct file *file = fget(fd);
12979 return ERR_PTR(-EBADF);
12981 if (file->f_op != &perf_fops) {
12983 return ERR_PTR(-EBADF);
12989 const struct perf_event *perf_get_event(struct file *file)
12991 if (file->f_op != &perf_fops)
12992 return ERR_PTR(-EINVAL);
12994 return file->private_data;
12997 const struct perf_event_attr *perf_event_attrs(struct perf_event *event)
13000 return ERR_PTR(-EINVAL);
13002 return &event->attr;
13006 * Inherit an event from parent task to child task.
13009 * - valid pointer on success
13010 * - NULL for orphaned events
13011 * - IS_ERR() on error
13013 static struct perf_event *
13014 inherit_event(struct perf_event *parent_event,
13015 struct task_struct *parent,
13016 struct perf_event_context *parent_ctx,
13017 struct task_struct *child,
13018 struct perf_event *group_leader,
13019 struct perf_event_context *child_ctx)
13021 enum perf_event_state parent_state = parent_event->state;
13022 struct perf_event *child_event;
13023 unsigned long flags;
13026 * Instead of creating recursive hierarchies of events,
13027 * we link inherited events back to the original parent,
13028 * which has a filp for sure, which we use as the reference
13031 if (parent_event->parent)
13032 parent_event = parent_event->parent;
13034 child_event = perf_event_alloc(&parent_event->attr,
13037 group_leader, parent_event,
13039 if (IS_ERR(child_event))
13040 return child_event;
13043 if ((child_event->attach_state & PERF_ATTACH_TASK_DATA) &&
13044 !child_ctx->task_ctx_data) {
13045 struct pmu *pmu = child_event->pmu;
13047 child_ctx->task_ctx_data = alloc_task_ctx_data(pmu);
13048 if (!child_ctx->task_ctx_data) {
13049 free_event(child_event);
13050 return ERR_PTR(-ENOMEM);
13055 * is_orphaned_event() and list_add_tail(&parent_event->child_list)
13056 * must be under the same lock in order to serialize against
13057 * perf_event_release_kernel(), such that either we must observe
13058 * is_orphaned_event() or they will observe us on the child_list.
13060 mutex_lock(&parent_event->child_mutex);
13061 if (is_orphaned_event(parent_event) ||
13062 !atomic_long_inc_not_zero(&parent_event->refcount)) {
13063 mutex_unlock(&parent_event->child_mutex);
13064 /* task_ctx_data is freed with child_ctx */
13065 free_event(child_event);
13069 get_ctx(child_ctx);
13072 * Make the child state follow the state of the parent event,
13073 * not its attr.disabled bit. We hold the parent's mutex,
13074 * so we won't race with perf_event_{en, dis}able_family.
13076 if (parent_state >= PERF_EVENT_STATE_INACTIVE)
13077 child_event->state = PERF_EVENT_STATE_INACTIVE;
13079 child_event->state = PERF_EVENT_STATE_OFF;
13081 if (parent_event->attr.freq) {
13082 u64 sample_period = parent_event->hw.sample_period;
13083 struct hw_perf_event *hwc = &child_event->hw;
13085 hwc->sample_period = sample_period;
13086 hwc->last_period = sample_period;
13088 local64_set(&hwc->period_left, sample_period);
13091 child_event->ctx = child_ctx;
13092 child_event->overflow_handler = parent_event->overflow_handler;
13093 child_event->overflow_handler_context
13094 = parent_event->overflow_handler_context;
13097 * Precalculate sample_data sizes
13099 perf_event__header_size(child_event);
13100 perf_event__id_header_size(child_event);
13103 * Link it up in the child's context:
13105 raw_spin_lock_irqsave(&child_ctx->lock, flags);
13106 add_event_to_ctx(child_event, child_ctx);
13107 child_event->attach_state |= PERF_ATTACH_CHILD;
13108 raw_spin_unlock_irqrestore(&child_ctx->lock, flags);
13111 * Link this into the parent event's child list
13113 list_add_tail(&child_event->child_list, &parent_event->child_list);
13114 mutex_unlock(&parent_event->child_mutex);
13116 return child_event;
13120 * Inherits an event group.
13122 * This will quietly suppress orphaned events; !inherit_event() is not an error.
13123 * This matches with perf_event_release_kernel() removing all child events.
13129 static int inherit_group(struct perf_event *parent_event,
13130 struct task_struct *parent,
13131 struct perf_event_context *parent_ctx,
13132 struct task_struct *child,
13133 struct perf_event_context *child_ctx)
13135 struct perf_event *leader;
13136 struct perf_event *sub;
13137 struct perf_event *child_ctr;
13139 leader = inherit_event(parent_event, parent, parent_ctx,
13140 child, NULL, child_ctx);
13141 if (IS_ERR(leader))
13142 return PTR_ERR(leader);
13144 * @leader can be NULL here because of is_orphaned_event(). In this
13145 * case inherit_event() will create individual events, similar to what
13146 * perf_group_detach() would do anyway.
13148 for_each_sibling_event(sub, parent_event) {
13149 child_ctr = inherit_event(sub, parent, parent_ctx,
13150 child, leader, child_ctx);
13151 if (IS_ERR(child_ctr))
13152 return PTR_ERR(child_ctr);
13154 if (sub->aux_event == parent_event && child_ctr &&
13155 !perf_get_aux_event(child_ctr, leader))
13162 * Creates the child task context and tries to inherit the event-group.
13164 * Clears @inherited_all on !attr.inherited or error. Note that we'll leave
13165 * inherited_all set when we 'fail' to inherit an orphaned event; this is
13166 * consistent with perf_event_release_kernel() removing all child events.
13173 inherit_task_group(struct perf_event *event, struct task_struct *parent,
13174 struct perf_event_context *parent_ctx,
13175 struct task_struct *child, int ctxn,
13176 u64 clone_flags, int *inherited_all)
13179 struct perf_event_context *child_ctx;
13181 if (!event->attr.inherit ||
13182 (event->attr.inherit_thread && !(clone_flags & CLONE_THREAD)) ||
13183 /* Do not inherit if sigtrap and signal handlers were cleared. */
13184 (event->attr.sigtrap && (clone_flags & CLONE_CLEAR_SIGHAND))) {
13185 *inherited_all = 0;
13189 child_ctx = child->perf_event_ctxp[ctxn];
13192 * This is executed from the parent task context, so
13193 * inherit events that have been marked for cloning.
13194 * First allocate and initialize a context for the
13197 child_ctx = alloc_perf_context(parent_ctx->pmu, child);
13201 child->perf_event_ctxp[ctxn] = child_ctx;
13204 ret = inherit_group(event, parent, parent_ctx,
13208 *inherited_all = 0;
13214 * Initialize the perf_event context in task_struct
13216 static int perf_event_init_context(struct task_struct *child, int ctxn,
13219 struct perf_event_context *child_ctx, *parent_ctx;
13220 struct perf_event_context *cloned_ctx;
13221 struct perf_event *event;
13222 struct task_struct *parent = current;
13223 int inherited_all = 1;
13224 unsigned long flags;
13227 if (likely(!parent->perf_event_ctxp[ctxn]))
13231 * If the parent's context is a clone, pin it so it won't get
13232 * swapped under us.
13234 parent_ctx = perf_pin_task_context(parent, ctxn);
13239 * No need to check if parent_ctx != NULL here; since we saw
13240 * it non-NULL earlier, the only reason for it to become NULL
13241 * is if we exit, and since we're currently in the middle of
13242 * a fork we can't be exiting at the same time.
13246 * Lock the parent list. No need to lock the child - not PID
13247 * hashed yet and not running, so nobody can access it.
13249 mutex_lock(&parent_ctx->mutex);
13252 * We dont have to disable NMIs - we are only looking at
13253 * the list, not manipulating it:
13255 perf_event_groups_for_each(event, &parent_ctx->pinned_groups) {
13256 ret = inherit_task_group(event, parent, parent_ctx,
13257 child, ctxn, clone_flags,
13264 * We can't hold ctx->lock when iterating the ->flexible_group list due
13265 * to allocations, but we need to prevent rotation because
13266 * rotate_ctx() will change the list from interrupt context.
13268 raw_spin_lock_irqsave(&parent_ctx->lock, flags);
13269 parent_ctx->rotate_disable = 1;
13270 raw_spin_unlock_irqrestore(&parent_ctx->lock, flags);
13272 perf_event_groups_for_each(event, &parent_ctx->flexible_groups) {
13273 ret = inherit_task_group(event, parent, parent_ctx,
13274 child, ctxn, clone_flags,
13280 raw_spin_lock_irqsave(&parent_ctx->lock, flags);
13281 parent_ctx->rotate_disable = 0;
13283 child_ctx = child->perf_event_ctxp[ctxn];
13285 if (child_ctx && inherited_all) {
13287 * Mark the child context as a clone of the parent
13288 * context, or of whatever the parent is a clone of.
13290 * Note that if the parent is a clone, the holding of
13291 * parent_ctx->lock avoids it from being uncloned.
13293 cloned_ctx = parent_ctx->parent_ctx;
13295 child_ctx->parent_ctx = cloned_ctx;
13296 child_ctx->parent_gen = parent_ctx->parent_gen;
13298 child_ctx->parent_ctx = parent_ctx;
13299 child_ctx->parent_gen = parent_ctx->generation;
13301 get_ctx(child_ctx->parent_ctx);
13304 raw_spin_unlock_irqrestore(&parent_ctx->lock, flags);
13306 mutex_unlock(&parent_ctx->mutex);
13308 perf_unpin_context(parent_ctx);
13309 put_ctx(parent_ctx);
13315 * Initialize the perf_event context in task_struct
13317 int perf_event_init_task(struct task_struct *child, u64 clone_flags)
13321 memset(child->perf_event_ctxp, 0, sizeof(child->perf_event_ctxp));
13322 mutex_init(&child->perf_event_mutex);
13323 INIT_LIST_HEAD(&child->perf_event_list);
13325 for_each_task_context_nr(ctxn) {
13326 ret = perf_event_init_context(child, ctxn, clone_flags);
13328 perf_event_free_task(child);
13336 static void __init perf_event_init_all_cpus(void)
13338 struct swevent_htable *swhash;
13341 zalloc_cpumask_var(&perf_online_mask, GFP_KERNEL);
13343 for_each_possible_cpu(cpu) {
13344 swhash = &per_cpu(swevent_htable, cpu);
13345 mutex_init(&swhash->hlist_mutex);
13346 INIT_LIST_HEAD(&per_cpu(active_ctx_list, cpu));
13348 INIT_LIST_HEAD(&per_cpu(pmu_sb_events.list, cpu));
13349 raw_spin_lock_init(&per_cpu(pmu_sb_events.lock, cpu));
13351 #ifdef CONFIG_CGROUP_PERF
13352 INIT_LIST_HEAD(&per_cpu(cgrp_cpuctx_list, cpu));
13354 INIT_LIST_HEAD(&per_cpu(sched_cb_list, cpu));
13358 static void perf_swevent_init_cpu(unsigned int cpu)
13360 struct swevent_htable *swhash = &per_cpu(swevent_htable, cpu);
13362 mutex_lock(&swhash->hlist_mutex);
13363 if (swhash->hlist_refcount > 0 && !swevent_hlist_deref(swhash)) {
13364 struct swevent_hlist *hlist;
13366 hlist = kzalloc_node(sizeof(*hlist), GFP_KERNEL, cpu_to_node(cpu));
13368 rcu_assign_pointer(swhash->swevent_hlist, hlist);
13370 mutex_unlock(&swhash->hlist_mutex);
13373 #if defined CONFIG_HOTPLUG_CPU || defined CONFIG_KEXEC_CORE
13374 static void __perf_event_exit_context(void *__info)
13376 struct perf_event_context *ctx = __info;
13377 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
13378 struct perf_event *event;
13380 raw_spin_lock(&ctx->lock);
13381 ctx_sched_out(ctx, cpuctx, EVENT_TIME);
13382 list_for_each_entry(event, &ctx->event_list, event_entry)
13383 __perf_remove_from_context(event, cpuctx, ctx, (void *)DETACH_GROUP);
13384 raw_spin_unlock(&ctx->lock);
13387 static void perf_event_exit_cpu_context(int cpu)
13389 struct perf_cpu_context *cpuctx;
13390 struct perf_event_context *ctx;
13393 mutex_lock(&pmus_lock);
13394 list_for_each_entry(pmu, &pmus, entry) {
13395 cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
13396 ctx = &cpuctx->ctx;
13398 mutex_lock(&ctx->mutex);
13399 smp_call_function_single(cpu, __perf_event_exit_context, ctx, 1);
13400 cpuctx->online = 0;
13401 mutex_unlock(&ctx->mutex);
13403 cpumask_clear_cpu(cpu, perf_online_mask);
13404 mutex_unlock(&pmus_lock);
13408 static void perf_event_exit_cpu_context(int cpu) { }
13412 int perf_event_init_cpu(unsigned int cpu)
13414 struct perf_cpu_context *cpuctx;
13415 struct perf_event_context *ctx;
13418 perf_swevent_init_cpu(cpu);
13420 mutex_lock(&pmus_lock);
13421 cpumask_set_cpu(cpu, perf_online_mask);
13422 list_for_each_entry(pmu, &pmus, entry) {
13423 cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
13424 ctx = &cpuctx->ctx;
13426 mutex_lock(&ctx->mutex);
13427 cpuctx->online = 1;
13428 mutex_unlock(&ctx->mutex);
13430 mutex_unlock(&pmus_lock);
13435 int perf_event_exit_cpu(unsigned int cpu)
13437 perf_event_exit_cpu_context(cpu);
13442 perf_reboot(struct notifier_block *notifier, unsigned long val, void *v)
13446 for_each_online_cpu(cpu)
13447 perf_event_exit_cpu(cpu);
13453 * Run the perf reboot notifier at the very last possible moment so that
13454 * the generic watchdog code runs as long as possible.
13456 static struct notifier_block perf_reboot_notifier = {
13457 .notifier_call = perf_reboot,
13458 .priority = INT_MIN,
13461 void __init perf_event_init(void)
13465 idr_init(&pmu_idr);
13467 perf_event_init_all_cpus();
13468 init_srcu_struct(&pmus_srcu);
13469 perf_pmu_register(&perf_swevent, "software", PERF_TYPE_SOFTWARE);
13470 perf_pmu_register(&perf_cpu_clock, NULL, -1);
13471 perf_pmu_register(&perf_task_clock, NULL, -1);
13472 perf_tp_register();
13473 perf_event_init_cpu(smp_processor_id());
13474 register_reboot_notifier(&perf_reboot_notifier);
13476 ret = init_hw_breakpoint();
13477 WARN(ret, "hw_breakpoint initialization failed with: %d", ret);
13479 perf_event_cache = KMEM_CACHE(perf_event, SLAB_PANIC);
13482 * Build time assertion that we keep the data_head at the intended
13483 * location. IOW, validation we got the __reserved[] size right.
13485 BUILD_BUG_ON((offsetof(struct perf_event_mmap_page, data_head))
13489 ssize_t perf_event_sysfs_show(struct device *dev, struct device_attribute *attr,
13492 struct perf_pmu_events_attr *pmu_attr =
13493 container_of(attr, struct perf_pmu_events_attr, attr);
13495 if (pmu_attr->event_str)
13496 return sprintf(page, "%s\n", pmu_attr->event_str);
13500 EXPORT_SYMBOL_GPL(perf_event_sysfs_show);
13502 static int __init perf_event_sysfs_init(void)
13507 mutex_lock(&pmus_lock);
13509 ret = bus_register(&pmu_bus);
13513 list_for_each_entry(pmu, &pmus, entry) {
13514 if (!pmu->name || pmu->type < 0)
13517 ret = pmu_dev_alloc(pmu);
13518 WARN(ret, "Failed to register pmu: %s, reason %d\n", pmu->name, ret);
13520 pmu_bus_running = 1;
13524 mutex_unlock(&pmus_lock);
13528 device_initcall(perf_event_sysfs_init);
13530 #ifdef CONFIG_CGROUP_PERF
13531 static struct cgroup_subsys_state *
13532 perf_cgroup_css_alloc(struct cgroup_subsys_state *parent_css)
13534 struct perf_cgroup *jc;
13536 jc = kzalloc(sizeof(*jc), GFP_KERNEL);
13538 return ERR_PTR(-ENOMEM);
13540 jc->info = alloc_percpu(struct perf_cgroup_info);
13543 return ERR_PTR(-ENOMEM);
13549 static void perf_cgroup_css_free(struct cgroup_subsys_state *css)
13551 struct perf_cgroup *jc = container_of(css, struct perf_cgroup, css);
13553 free_percpu(jc->info);
13557 static int perf_cgroup_css_online(struct cgroup_subsys_state *css)
13559 perf_event_cgroup(css->cgroup);
13563 static int __perf_cgroup_move(void *info)
13565 struct task_struct *task = info;
13567 perf_cgroup_switch(task, PERF_CGROUP_SWOUT | PERF_CGROUP_SWIN);
13572 static void perf_cgroup_attach(struct cgroup_taskset *tset)
13574 struct task_struct *task;
13575 struct cgroup_subsys_state *css;
13577 cgroup_taskset_for_each(task, css, tset)
13578 task_function_call(task, __perf_cgroup_move, task);
13581 struct cgroup_subsys perf_event_cgrp_subsys = {
13582 .css_alloc = perf_cgroup_css_alloc,
13583 .css_free = perf_cgroup_css_free,
13584 .css_online = perf_cgroup_css_online,
13585 .attach = perf_cgroup_attach,
13587 * Implicitly enable on dfl hierarchy so that perf events can
13588 * always be filtered by cgroup2 path as long as perf_event
13589 * controller is not mounted on a legacy hierarchy.
13591 .implicit_on_dfl = true,
13594 #endif /* CONFIG_CGROUP_PERF */
13596 DEFINE_STATIC_CALL_RET0(perf_snapshot_branch_stack, perf_snapshot_branch_stack_t);