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 * @func: the function to be called
136 * @info: the function call argument
138 * Calls the function @func on the remote cpu.
140 * returns: @func return value or -ENXIO when the cpu is offline
142 static int cpu_function_call(int cpu, remote_function_f func, void *info)
144 struct remote_function_call data = {
148 .ret = -ENXIO, /* No such CPU */
151 smp_call_function_single(cpu, remote_function, &data, 1);
156 static inline struct perf_cpu_context *
157 __get_cpu_context(struct perf_event_context *ctx)
159 return this_cpu_ptr(ctx->pmu->pmu_cpu_context);
162 static void perf_ctx_lock(struct perf_cpu_context *cpuctx,
163 struct perf_event_context *ctx)
165 raw_spin_lock(&cpuctx->ctx.lock);
167 raw_spin_lock(&ctx->lock);
170 static void perf_ctx_unlock(struct perf_cpu_context *cpuctx,
171 struct perf_event_context *ctx)
174 raw_spin_unlock(&ctx->lock);
175 raw_spin_unlock(&cpuctx->ctx.lock);
178 #define TASK_TOMBSTONE ((void *)-1L)
180 static bool is_kernel_event(struct perf_event *event)
182 return READ_ONCE(event->owner) == TASK_TOMBSTONE;
186 * On task ctx scheduling...
188 * When !ctx->nr_events a task context will not be scheduled. This means
189 * we can disable the scheduler hooks (for performance) without leaving
190 * pending task ctx state.
192 * This however results in two special cases:
194 * - removing the last event from a task ctx; this is relatively straight
195 * forward and is done in __perf_remove_from_context.
197 * - adding the first event to a task ctx; this is tricky because we cannot
198 * rely on ctx->is_active and therefore cannot use event_function_call().
199 * See perf_install_in_context().
201 * If ctx->nr_events, then ctx->is_active and cpuctx->task_ctx are set.
204 typedef void (*event_f)(struct perf_event *, struct perf_cpu_context *,
205 struct perf_event_context *, void *);
207 struct event_function_struct {
208 struct perf_event *event;
213 static int event_function(void *info)
215 struct event_function_struct *efs = info;
216 struct perf_event *event = efs->event;
217 struct perf_event_context *ctx = event->ctx;
218 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
219 struct perf_event_context *task_ctx = cpuctx->task_ctx;
222 lockdep_assert_irqs_disabled();
224 perf_ctx_lock(cpuctx, task_ctx);
226 * Since we do the IPI call without holding ctx->lock things can have
227 * changed, double check we hit the task we set out to hit.
230 if (ctx->task != current) {
236 * We only use event_function_call() on established contexts,
237 * and event_function() is only ever called when active (or
238 * rather, we'll have bailed in task_function_call() or the
239 * above ctx->task != current test), therefore we must have
240 * ctx->is_active here.
242 WARN_ON_ONCE(!ctx->is_active);
244 * And since we have ctx->is_active, cpuctx->task_ctx must
247 WARN_ON_ONCE(task_ctx != ctx);
249 WARN_ON_ONCE(&cpuctx->ctx != ctx);
252 efs->func(event, cpuctx, ctx, efs->data);
254 perf_ctx_unlock(cpuctx, task_ctx);
259 static void event_function_call(struct perf_event *event, event_f func, void *data)
261 struct perf_event_context *ctx = event->ctx;
262 struct task_struct *task = READ_ONCE(ctx->task); /* verified in event_function */
263 struct event_function_struct efs = {
269 if (!event->parent) {
271 * If this is a !child event, we must hold ctx::mutex to
272 * stabilize the event->ctx relation. See
273 * perf_event_ctx_lock().
275 lockdep_assert_held(&ctx->mutex);
279 cpu_function_call(event->cpu, event_function, &efs);
283 if (task == TASK_TOMBSTONE)
287 if (!task_function_call(task, event_function, &efs))
290 raw_spin_lock_irq(&ctx->lock);
292 * Reload the task pointer, it might have been changed by
293 * a concurrent perf_event_context_sched_out().
296 if (task == TASK_TOMBSTONE) {
297 raw_spin_unlock_irq(&ctx->lock);
300 if (ctx->is_active) {
301 raw_spin_unlock_irq(&ctx->lock);
304 func(event, NULL, ctx, data);
305 raw_spin_unlock_irq(&ctx->lock);
309 * Similar to event_function_call() + event_function(), but hard assumes IRQs
310 * are already disabled and we're on the right CPU.
312 static void event_function_local(struct perf_event *event, event_f func, void *data)
314 struct perf_event_context *ctx = event->ctx;
315 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
316 struct task_struct *task = READ_ONCE(ctx->task);
317 struct perf_event_context *task_ctx = NULL;
319 lockdep_assert_irqs_disabled();
322 if (task == TASK_TOMBSTONE)
328 perf_ctx_lock(cpuctx, task_ctx);
331 if (task == TASK_TOMBSTONE)
336 * We must be either inactive or active and the right task,
337 * otherwise we're screwed, since we cannot IPI to somewhere
340 if (ctx->is_active) {
341 if (WARN_ON_ONCE(task != current))
344 if (WARN_ON_ONCE(cpuctx->task_ctx != ctx))
348 WARN_ON_ONCE(&cpuctx->ctx != ctx);
351 func(event, cpuctx, ctx, data);
353 perf_ctx_unlock(cpuctx, task_ctx);
356 #define PERF_FLAG_ALL (PERF_FLAG_FD_NO_GROUP |\
357 PERF_FLAG_FD_OUTPUT |\
358 PERF_FLAG_PID_CGROUP |\
359 PERF_FLAG_FD_CLOEXEC)
362 * branch priv levels that need permission checks
364 #define PERF_SAMPLE_BRANCH_PERM_PLM \
365 (PERF_SAMPLE_BRANCH_KERNEL |\
366 PERF_SAMPLE_BRANCH_HV)
369 EVENT_FLEXIBLE = 0x1,
372 /* see ctx_resched() for details */
374 EVENT_ALL = EVENT_FLEXIBLE | EVENT_PINNED,
378 * perf_sched_events : >0 events exist
379 * perf_cgroup_events: >0 per-cpu cgroup events exist on this cpu
382 static void perf_sched_delayed(struct work_struct *work);
383 DEFINE_STATIC_KEY_FALSE(perf_sched_events);
384 static DECLARE_DELAYED_WORK(perf_sched_work, perf_sched_delayed);
385 static DEFINE_MUTEX(perf_sched_mutex);
386 static atomic_t perf_sched_count;
388 static DEFINE_PER_CPU(atomic_t, perf_cgroup_events);
389 static DEFINE_PER_CPU(int, perf_sched_cb_usages);
390 static DEFINE_PER_CPU(struct pmu_event_list, pmu_sb_events);
392 static atomic_t nr_mmap_events __read_mostly;
393 static atomic_t nr_comm_events __read_mostly;
394 static atomic_t nr_namespaces_events __read_mostly;
395 static atomic_t nr_task_events __read_mostly;
396 static atomic_t nr_freq_events __read_mostly;
397 static atomic_t nr_switch_events __read_mostly;
398 static atomic_t nr_ksymbol_events __read_mostly;
399 static atomic_t nr_bpf_events __read_mostly;
400 static atomic_t nr_cgroup_events __read_mostly;
401 static atomic_t nr_text_poke_events __read_mostly;
402 static atomic_t nr_build_id_events __read_mostly;
404 static LIST_HEAD(pmus);
405 static DEFINE_MUTEX(pmus_lock);
406 static struct srcu_struct pmus_srcu;
407 static cpumask_var_t perf_online_mask;
408 static struct kmem_cache *perf_event_cache;
411 * perf event paranoia level:
412 * -1 - not paranoid at all
413 * 0 - disallow raw tracepoint access for unpriv
414 * 1 - disallow cpu events for unpriv
415 * 2 - disallow kernel profiling for unpriv
417 int sysctl_perf_event_paranoid __read_mostly = 2;
419 /* Minimum for 512 kiB + 1 user control page */
420 int sysctl_perf_event_mlock __read_mostly = 512 + (PAGE_SIZE / 1024); /* 'free' kiB per user */
423 * max perf event sample rate
425 #define DEFAULT_MAX_SAMPLE_RATE 100000
426 #define DEFAULT_SAMPLE_PERIOD_NS (NSEC_PER_SEC / DEFAULT_MAX_SAMPLE_RATE)
427 #define DEFAULT_CPU_TIME_MAX_PERCENT 25
429 int sysctl_perf_event_sample_rate __read_mostly = DEFAULT_MAX_SAMPLE_RATE;
431 static int max_samples_per_tick __read_mostly = DIV_ROUND_UP(DEFAULT_MAX_SAMPLE_RATE, HZ);
432 static int perf_sample_period_ns __read_mostly = DEFAULT_SAMPLE_PERIOD_NS;
434 static int perf_sample_allowed_ns __read_mostly =
435 DEFAULT_SAMPLE_PERIOD_NS * DEFAULT_CPU_TIME_MAX_PERCENT / 100;
437 static void update_perf_cpu_limits(void)
439 u64 tmp = perf_sample_period_ns;
441 tmp *= sysctl_perf_cpu_time_max_percent;
442 tmp = div_u64(tmp, 100);
446 WRITE_ONCE(perf_sample_allowed_ns, tmp);
449 static bool perf_rotate_context(struct perf_cpu_context *cpuctx);
451 int perf_proc_update_handler(struct ctl_table *table, int write,
452 void *buffer, size_t *lenp, loff_t *ppos)
455 int perf_cpu = sysctl_perf_cpu_time_max_percent;
457 * If throttling is disabled don't allow the write:
459 if (write && (perf_cpu == 100 || perf_cpu == 0))
462 ret = proc_dointvec_minmax(table, write, buffer, lenp, ppos);
466 max_samples_per_tick = DIV_ROUND_UP(sysctl_perf_event_sample_rate, HZ);
467 perf_sample_period_ns = NSEC_PER_SEC / sysctl_perf_event_sample_rate;
468 update_perf_cpu_limits();
473 int sysctl_perf_cpu_time_max_percent __read_mostly = DEFAULT_CPU_TIME_MAX_PERCENT;
475 int perf_cpu_time_max_percent_handler(struct ctl_table *table, int write,
476 void *buffer, size_t *lenp, loff_t *ppos)
478 int ret = proc_dointvec_minmax(table, write, buffer, lenp, ppos);
483 if (sysctl_perf_cpu_time_max_percent == 100 ||
484 sysctl_perf_cpu_time_max_percent == 0) {
486 "perf: Dynamic interrupt throttling disabled, can hang your system!\n");
487 WRITE_ONCE(perf_sample_allowed_ns, 0);
489 update_perf_cpu_limits();
496 * perf samples are done in some very critical code paths (NMIs).
497 * If they take too much CPU time, the system can lock up and not
498 * get any real work done. This will drop the sample rate when
499 * we detect that events are taking too long.
501 #define NR_ACCUMULATED_SAMPLES 128
502 static DEFINE_PER_CPU(u64, running_sample_length);
504 static u64 __report_avg;
505 static u64 __report_allowed;
507 static void perf_duration_warn(struct irq_work *w)
509 printk_ratelimited(KERN_INFO
510 "perf: interrupt took too long (%lld > %lld), lowering "
511 "kernel.perf_event_max_sample_rate to %d\n",
512 __report_avg, __report_allowed,
513 sysctl_perf_event_sample_rate);
516 static DEFINE_IRQ_WORK(perf_duration_work, perf_duration_warn);
518 void perf_sample_event_took(u64 sample_len_ns)
520 u64 max_len = READ_ONCE(perf_sample_allowed_ns);
528 /* Decay the counter by 1 average sample. */
529 running_len = __this_cpu_read(running_sample_length);
530 running_len -= running_len/NR_ACCUMULATED_SAMPLES;
531 running_len += sample_len_ns;
532 __this_cpu_write(running_sample_length, running_len);
535 * Note: this will be biased artifically low until we have
536 * seen NR_ACCUMULATED_SAMPLES. Doing it this way keeps us
537 * from having to maintain a count.
539 avg_len = running_len/NR_ACCUMULATED_SAMPLES;
540 if (avg_len <= max_len)
543 __report_avg = avg_len;
544 __report_allowed = max_len;
547 * Compute a throttle threshold 25% below the current duration.
549 avg_len += avg_len / 4;
550 max = (TICK_NSEC / 100) * sysctl_perf_cpu_time_max_percent;
556 WRITE_ONCE(perf_sample_allowed_ns, avg_len);
557 WRITE_ONCE(max_samples_per_tick, max);
559 sysctl_perf_event_sample_rate = max * HZ;
560 perf_sample_period_ns = NSEC_PER_SEC / sysctl_perf_event_sample_rate;
562 if (!irq_work_queue(&perf_duration_work)) {
563 early_printk("perf: interrupt took too long (%lld > %lld), lowering "
564 "kernel.perf_event_max_sample_rate to %d\n",
565 __report_avg, __report_allowed,
566 sysctl_perf_event_sample_rate);
570 static atomic64_t perf_event_id;
572 static void cpu_ctx_sched_out(struct perf_cpu_context *cpuctx,
573 enum event_type_t event_type);
575 static void cpu_ctx_sched_in(struct perf_cpu_context *cpuctx,
576 enum event_type_t event_type,
577 struct task_struct *task);
579 static void update_context_time(struct perf_event_context *ctx);
580 static u64 perf_event_time(struct perf_event *event);
582 void __weak perf_event_print_debug(void) { }
584 static inline u64 perf_clock(void)
586 return local_clock();
589 static inline u64 perf_event_clock(struct perf_event *event)
591 return event->clock();
595 * State based event timekeeping...
597 * The basic idea is to use event->state to determine which (if any) time
598 * fields to increment with the current delta. This means we only need to
599 * update timestamps when we change state or when they are explicitly requested
602 * Event groups make things a little more complicated, but not terribly so. The
603 * rules for a group are that if the group leader is OFF the entire group is
604 * OFF, irrespecive of what the group member states are. This results in
605 * __perf_effective_state().
607 * A futher ramification is that when a group leader flips between OFF and
608 * !OFF, we need to update all group member times.
611 * NOTE: perf_event_time() is based on the (cgroup) context time, and thus we
612 * need to make sure the relevant context time is updated before we try and
613 * update our timestamps.
616 static __always_inline enum perf_event_state
617 __perf_effective_state(struct perf_event *event)
619 struct perf_event *leader = event->group_leader;
621 if (leader->state <= PERF_EVENT_STATE_OFF)
622 return leader->state;
627 static __always_inline void
628 __perf_update_times(struct perf_event *event, u64 now, u64 *enabled, u64 *running)
630 enum perf_event_state state = __perf_effective_state(event);
631 u64 delta = now - event->tstamp;
633 *enabled = event->total_time_enabled;
634 if (state >= PERF_EVENT_STATE_INACTIVE)
637 *running = event->total_time_running;
638 if (state >= PERF_EVENT_STATE_ACTIVE)
642 static void perf_event_update_time(struct perf_event *event)
644 u64 now = perf_event_time(event);
646 __perf_update_times(event, now, &event->total_time_enabled,
647 &event->total_time_running);
651 static void perf_event_update_sibling_time(struct perf_event *leader)
653 struct perf_event *sibling;
655 for_each_sibling_event(sibling, leader)
656 perf_event_update_time(sibling);
660 perf_event_set_state(struct perf_event *event, enum perf_event_state state)
662 if (event->state == state)
665 perf_event_update_time(event);
667 * If a group leader gets enabled/disabled all its siblings
670 if ((event->state < 0) ^ (state < 0))
671 perf_event_update_sibling_time(event);
673 WRITE_ONCE(event->state, state);
676 #ifdef CONFIG_CGROUP_PERF
679 perf_cgroup_match(struct perf_event *event)
681 struct perf_event_context *ctx = event->ctx;
682 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
684 /* @event doesn't care about cgroup */
688 /* wants specific cgroup scope but @cpuctx isn't associated with any */
693 * Cgroup scoping is recursive. An event enabled for a cgroup is
694 * also enabled for all its descendant cgroups. If @cpuctx's
695 * cgroup is a descendant of @event's (the test covers identity
696 * case), it's a match.
698 return cgroup_is_descendant(cpuctx->cgrp->css.cgroup,
699 event->cgrp->css.cgroup);
702 static inline void perf_detach_cgroup(struct perf_event *event)
704 css_put(&event->cgrp->css);
708 static inline int is_cgroup_event(struct perf_event *event)
710 return event->cgrp != NULL;
713 static inline u64 perf_cgroup_event_time(struct perf_event *event)
715 struct perf_cgroup_info *t;
717 t = per_cpu_ptr(event->cgrp->info, event->cpu);
721 static inline void __update_cgrp_time(struct perf_cgroup *cgrp)
723 struct perf_cgroup_info *info;
728 info = this_cpu_ptr(cgrp->info);
730 info->time += now - info->timestamp;
731 info->timestamp = now;
734 static inline void update_cgrp_time_from_cpuctx(struct perf_cpu_context *cpuctx)
736 struct perf_cgroup *cgrp = cpuctx->cgrp;
737 struct cgroup_subsys_state *css;
740 for (css = &cgrp->css; css; css = css->parent) {
741 cgrp = container_of(css, struct perf_cgroup, css);
742 __update_cgrp_time(cgrp);
747 static inline void update_cgrp_time_from_event(struct perf_event *event)
749 struct perf_cgroup *cgrp;
752 * ensure we access cgroup data only when needed and
753 * when we know the cgroup is pinned (css_get)
755 if (!is_cgroup_event(event))
758 cgrp = perf_cgroup_from_task(current, event->ctx);
760 * Do not update time when cgroup is not active
762 if (cgroup_is_descendant(cgrp->css.cgroup, event->cgrp->css.cgroup))
763 __update_cgrp_time(event->cgrp);
767 perf_cgroup_set_timestamp(struct task_struct *task,
768 struct perf_event_context *ctx)
770 struct perf_cgroup *cgrp;
771 struct perf_cgroup_info *info;
772 struct cgroup_subsys_state *css;
775 * ctx->lock held by caller
776 * ensure we do not access cgroup data
777 * unless we have the cgroup pinned (css_get)
779 if (!task || !ctx->nr_cgroups)
782 cgrp = perf_cgroup_from_task(task, ctx);
784 for (css = &cgrp->css; css; css = css->parent) {
785 cgrp = container_of(css, struct perf_cgroup, css);
786 info = this_cpu_ptr(cgrp->info);
787 info->timestamp = ctx->timestamp;
791 static DEFINE_PER_CPU(struct list_head, cgrp_cpuctx_list);
793 #define PERF_CGROUP_SWOUT 0x1 /* cgroup switch out every event */
794 #define PERF_CGROUP_SWIN 0x2 /* cgroup switch in events based on task */
797 * reschedule events based on the cgroup constraint of task.
799 * mode SWOUT : schedule out everything
800 * mode SWIN : schedule in based on cgroup for next
802 static void perf_cgroup_switch(struct task_struct *task, int mode)
804 struct perf_cpu_context *cpuctx;
805 struct list_head *list;
809 * Disable interrupts and preemption to avoid this CPU's
810 * cgrp_cpuctx_entry to change under us.
812 local_irq_save(flags);
814 list = this_cpu_ptr(&cgrp_cpuctx_list);
815 list_for_each_entry(cpuctx, list, cgrp_cpuctx_entry) {
816 WARN_ON_ONCE(cpuctx->ctx.nr_cgroups == 0);
818 perf_ctx_lock(cpuctx, cpuctx->task_ctx);
819 perf_pmu_disable(cpuctx->ctx.pmu);
821 if (mode & PERF_CGROUP_SWOUT) {
822 cpu_ctx_sched_out(cpuctx, EVENT_ALL);
824 * must not be done before ctxswout due
825 * to event_filter_match() in event_sched_out()
830 if (mode & PERF_CGROUP_SWIN) {
831 WARN_ON_ONCE(cpuctx->cgrp);
833 * set cgrp before ctxsw in to allow
834 * event_filter_match() to not have to pass
836 * we pass the cpuctx->ctx to perf_cgroup_from_task()
837 * because cgorup events are only per-cpu
839 cpuctx->cgrp = perf_cgroup_from_task(task,
841 cpu_ctx_sched_in(cpuctx, EVENT_ALL, task);
843 perf_pmu_enable(cpuctx->ctx.pmu);
844 perf_ctx_unlock(cpuctx, cpuctx->task_ctx);
847 local_irq_restore(flags);
850 static inline void perf_cgroup_sched_out(struct task_struct *task,
851 struct task_struct *next)
853 struct perf_cgroup *cgrp1;
854 struct perf_cgroup *cgrp2 = NULL;
858 * we come here when we know perf_cgroup_events > 0
859 * we do not need to pass the ctx here because we know
860 * we are holding the rcu lock
862 cgrp1 = perf_cgroup_from_task(task, NULL);
863 cgrp2 = perf_cgroup_from_task(next, NULL);
866 * only schedule out current cgroup events if we know
867 * that we are switching to a different cgroup. Otherwise,
868 * do no touch the cgroup events.
871 perf_cgroup_switch(task, PERF_CGROUP_SWOUT);
876 static inline void perf_cgroup_sched_in(struct task_struct *prev,
877 struct task_struct *task)
879 struct perf_cgroup *cgrp1;
880 struct perf_cgroup *cgrp2 = NULL;
884 * we come here when we know perf_cgroup_events > 0
885 * we do not need to pass the ctx here because we know
886 * we are holding the rcu lock
888 cgrp1 = perf_cgroup_from_task(task, NULL);
889 cgrp2 = perf_cgroup_from_task(prev, NULL);
892 * only need to schedule in cgroup events if we are changing
893 * cgroup during ctxsw. Cgroup events were not scheduled
894 * out of ctxsw out if that was not the case.
897 perf_cgroup_switch(task, PERF_CGROUP_SWIN);
902 static int perf_cgroup_ensure_storage(struct perf_event *event,
903 struct cgroup_subsys_state *css)
905 struct perf_cpu_context *cpuctx;
906 struct perf_event **storage;
907 int cpu, heap_size, ret = 0;
910 * Allow storage to have sufficent space for an iterator for each
911 * possibly nested cgroup plus an iterator for events with no cgroup.
913 for (heap_size = 1; css; css = css->parent)
916 for_each_possible_cpu(cpu) {
917 cpuctx = per_cpu_ptr(event->pmu->pmu_cpu_context, cpu);
918 if (heap_size <= cpuctx->heap_size)
921 storage = kmalloc_node(heap_size * sizeof(struct perf_event *),
922 GFP_KERNEL, cpu_to_node(cpu));
928 raw_spin_lock_irq(&cpuctx->ctx.lock);
929 if (cpuctx->heap_size < heap_size) {
930 swap(cpuctx->heap, storage);
931 if (storage == cpuctx->heap_default)
933 cpuctx->heap_size = heap_size;
935 raw_spin_unlock_irq(&cpuctx->ctx.lock);
943 static inline int perf_cgroup_connect(int fd, struct perf_event *event,
944 struct perf_event_attr *attr,
945 struct perf_event *group_leader)
947 struct perf_cgroup *cgrp;
948 struct cgroup_subsys_state *css;
949 struct fd f = fdget(fd);
955 css = css_tryget_online_from_dir(f.file->f_path.dentry,
956 &perf_event_cgrp_subsys);
962 ret = perf_cgroup_ensure_storage(event, css);
966 cgrp = container_of(css, struct perf_cgroup, css);
970 * all events in a group must monitor
971 * the same cgroup because a task belongs
972 * to only one perf cgroup at a time
974 if (group_leader && group_leader->cgrp != cgrp) {
975 perf_detach_cgroup(event);
984 perf_cgroup_set_shadow_time(struct perf_event *event, u64 now)
986 struct perf_cgroup_info *t;
987 t = per_cpu_ptr(event->cgrp->info, event->cpu);
988 event->shadow_ctx_time = now - t->timestamp;
992 perf_cgroup_event_enable(struct perf_event *event, struct perf_event_context *ctx)
994 struct perf_cpu_context *cpuctx;
996 if (!is_cgroup_event(event))
1000 * Because cgroup events are always per-cpu events,
1001 * @ctx == &cpuctx->ctx.
1003 cpuctx = container_of(ctx, struct perf_cpu_context, ctx);
1006 * Since setting cpuctx->cgrp is conditional on the current @cgrp
1007 * matching the event's cgroup, we must do this for every new event,
1008 * because if the first would mismatch, the second would not try again
1009 * and we would leave cpuctx->cgrp unset.
1011 if (ctx->is_active && !cpuctx->cgrp) {
1012 struct perf_cgroup *cgrp = perf_cgroup_from_task(current, ctx);
1014 if (cgroup_is_descendant(cgrp->css.cgroup, event->cgrp->css.cgroup))
1015 cpuctx->cgrp = cgrp;
1018 if (ctx->nr_cgroups++)
1021 list_add(&cpuctx->cgrp_cpuctx_entry,
1022 per_cpu_ptr(&cgrp_cpuctx_list, event->cpu));
1026 perf_cgroup_event_disable(struct perf_event *event, struct perf_event_context *ctx)
1028 struct perf_cpu_context *cpuctx;
1030 if (!is_cgroup_event(event))
1034 * Because cgroup events are always per-cpu events,
1035 * @ctx == &cpuctx->ctx.
1037 cpuctx = container_of(ctx, struct perf_cpu_context, ctx);
1039 if (--ctx->nr_cgroups)
1042 if (ctx->is_active && cpuctx->cgrp)
1043 cpuctx->cgrp = NULL;
1045 list_del(&cpuctx->cgrp_cpuctx_entry);
1048 #else /* !CONFIG_CGROUP_PERF */
1051 perf_cgroup_match(struct perf_event *event)
1056 static inline void perf_detach_cgroup(struct perf_event *event)
1059 static inline int is_cgroup_event(struct perf_event *event)
1064 static inline void update_cgrp_time_from_event(struct perf_event *event)
1068 static inline void update_cgrp_time_from_cpuctx(struct perf_cpu_context *cpuctx)
1072 static inline void perf_cgroup_sched_out(struct task_struct *task,
1073 struct task_struct *next)
1077 static inline void perf_cgroup_sched_in(struct task_struct *prev,
1078 struct task_struct *task)
1082 static inline int perf_cgroup_connect(pid_t pid, struct perf_event *event,
1083 struct perf_event_attr *attr,
1084 struct perf_event *group_leader)
1090 perf_cgroup_set_timestamp(struct task_struct *task,
1091 struct perf_event_context *ctx)
1096 perf_cgroup_switch(struct task_struct *task, struct task_struct *next)
1101 perf_cgroup_set_shadow_time(struct perf_event *event, u64 now)
1105 static inline u64 perf_cgroup_event_time(struct perf_event *event)
1111 perf_cgroup_event_enable(struct perf_event *event, struct perf_event_context *ctx)
1116 perf_cgroup_event_disable(struct perf_event *event, struct perf_event_context *ctx)
1122 * set default to be dependent on timer tick just
1123 * like original code
1125 #define PERF_CPU_HRTIMER (1000 / HZ)
1127 * function must be called with interrupts disabled
1129 static enum hrtimer_restart perf_mux_hrtimer_handler(struct hrtimer *hr)
1131 struct perf_cpu_context *cpuctx;
1134 lockdep_assert_irqs_disabled();
1136 cpuctx = container_of(hr, struct perf_cpu_context, hrtimer);
1137 rotations = perf_rotate_context(cpuctx);
1139 raw_spin_lock(&cpuctx->hrtimer_lock);
1141 hrtimer_forward_now(hr, cpuctx->hrtimer_interval);
1143 cpuctx->hrtimer_active = 0;
1144 raw_spin_unlock(&cpuctx->hrtimer_lock);
1146 return rotations ? HRTIMER_RESTART : HRTIMER_NORESTART;
1149 static void __perf_mux_hrtimer_init(struct perf_cpu_context *cpuctx, int cpu)
1151 struct hrtimer *timer = &cpuctx->hrtimer;
1152 struct pmu *pmu = cpuctx->ctx.pmu;
1155 /* no multiplexing needed for SW PMU */
1156 if (pmu->task_ctx_nr == perf_sw_context)
1160 * check default is sane, if not set then force to
1161 * default interval (1/tick)
1163 interval = pmu->hrtimer_interval_ms;
1165 interval = pmu->hrtimer_interval_ms = PERF_CPU_HRTIMER;
1167 cpuctx->hrtimer_interval = ns_to_ktime(NSEC_PER_MSEC * interval);
1169 raw_spin_lock_init(&cpuctx->hrtimer_lock);
1170 hrtimer_init(timer, CLOCK_MONOTONIC, HRTIMER_MODE_ABS_PINNED_HARD);
1171 timer->function = perf_mux_hrtimer_handler;
1174 static int perf_mux_hrtimer_restart(struct perf_cpu_context *cpuctx)
1176 struct hrtimer *timer = &cpuctx->hrtimer;
1177 struct pmu *pmu = cpuctx->ctx.pmu;
1178 unsigned long flags;
1180 /* not for SW PMU */
1181 if (pmu->task_ctx_nr == perf_sw_context)
1184 raw_spin_lock_irqsave(&cpuctx->hrtimer_lock, flags);
1185 if (!cpuctx->hrtimer_active) {
1186 cpuctx->hrtimer_active = 1;
1187 hrtimer_forward_now(timer, cpuctx->hrtimer_interval);
1188 hrtimer_start_expires(timer, HRTIMER_MODE_ABS_PINNED_HARD);
1190 raw_spin_unlock_irqrestore(&cpuctx->hrtimer_lock, flags);
1195 void perf_pmu_disable(struct pmu *pmu)
1197 int *count = this_cpu_ptr(pmu->pmu_disable_count);
1199 pmu->pmu_disable(pmu);
1202 void perf_pmu_enable(struct pmu *pmu)
1204 int *count = this_cpu_ptr(pmu->pmu_disable_count);
1206 pmu->pmu_enable(pmu);
1209 static DEFINE_PER_CPU(struct list_head, active_ctx_list);
1212 * perf_event_ctx_activate(), perf_event_ctx_deactivate(), and
1213 * perf_event_task_tick() are fully serialized because they're strictly cpu
1214 * affine and perf_event_ctx{activate,deactivate} are called with IRQs
1215 * disabled, while perf_event_task_tick is called from IRQ context.
1217 static void perf_event_ctx_activate(struct perf_event_context *ctx)
1219 struct list_head *head = this_cpu_ptr(&active_ctx_list);
1221 lockdep_assert_irqs_disabled();
1223 WARN_ON(!list_empty(&ctx->active_ctx_list));
1225 list_add(&ctx->active_ctx_list, head);
1228 static void perf_event_ctx_deactivate(struct perf_event_context *ctx)
1230 lockdep_assert_irqs_disabled();
1232 WARN_ON(list_empty(&ctx->active_ctx_list));
1234 list_del_init(&ctx->active_ctx_list);
1237 static void get_ctx(struct perf_event_context *ctx)
1239 refcount_inc(&ctx->refcount);
1242 static void *alloc_task_ctx_data(struct pmu *pmu)
1244 if (pmu->task_ctx_cache)
1245 return kmem_cache_zalloc(pmu->task_ctx_cache, GFP_KERNEL);
1250 static void free_task_ctx_data(struct pmu *pmu, void *task_ctx_data)
1252 if (pmu->task_ctx_cache && task_ctx_data)
1253 kmem_cache_free(pmu->task_ctx_cache, task_ctx_data);
1256 static void free_ctx(struct rcu_head *head)
1258 struct perf_event_context *ctx;
1260 ctx = container_of(head, struct perf_event_context, rcu_head);
1261 free_task_ctx_data(ctx->pmu, ctx->task_ctx_data);
1265 static void put_ctx(struct perf_event_context *ctx)
1267 if (refcount_dec_and_test(&ctx->refcount)) {
1268 if (ctx->parent_ctx)
1269 put_ctx(ctx->parent_ctx);
1270 if (ctx->task && ctx->task != TASK_TOMBSTONE)
1271 put_task_struct(ctx->task);
1272 call_rcu(&ctx->rcu_head, free_ctx);
1277 * Because of perf_event::ctx migration in sys_perf_event_open::move_group and
1278 * perf_pmu_migrate_context() we need some magic.
1280 * Those places that change perf_event::ctx will hold both
1281 * perf_event_ctx::mutex of the 'old' and 'new' ctx value.
1283 * Lock ordering is by mutex address. There are two other sites where
1284 * perf_event_context::mutex nests and those are:
1286 * - perf_event_exit_task_context() [ child , 0 ]
1287 * perf_event_exit_event()
1288 * put_event() [ parent, 1 ]
1290 * - perf_event_init_context() [ parent, 0 ]
1291 * inherit_task_group()
1294 * perf_event_alloc()
1296 * perf_try_init_event() [ child , 1 ]
1298 * While it appears there is an obvious deadlock here -- the parent and child
1299 * nesting levels are inverted between the two. This is in fact safe because
1300 * life-time rules separate them. That is an exiting task cannot fork, and a
1301 * spawning task cannot (yet) exit.
1303 * But remember that these are parent<->child context relations, and
1304 * migration does not affect children, therefore these two orderings should not
1307 * The change in perf_event::ctx does not affect children (as claimed above)
1308 * because the sys_perf_event_open() case will install a new event and break
1309 * the ctx parent<->child relation, and perf_pmu_migrate_context() is only
1310 * concerned with cpuctx and that doesn't have children.
1312 * The places that change perf_event::ctx will issue:
1314 * perf_remove_from_context();
1315 * synchronize_rcu();
1316 * perf_install_in_context();
1318 * to affect the change. The remove_from_context() + synchronize_rcu() should
1319 * quiesce the event, after which we can install it in the new location. This
1320 * means that only external vectors (perf_fops, prctl) can perturb the event
1321 * while in transit. Therefore all such accessors should also acquire
1322 * perf_event_context::mutex to serialize against this.
1324 * However; because event->ctx can change while we're waiting to acquire
1325 * ctx->mutex we must be careful and use the below perf_event_ctx_lock()
1330 * task_struct::perf_event_mutex
1331 * perf_event_context::mutex
1332 * perf_event::child_mutex;
1333 * perf_event_context::lock
1334 * perf_event::mmap_mutex
1336 * perf_addr_filters_head::lock
1340 * cpuctx->mutex / perf_event_context::mutex
1342 static struct perf_event_context *
1343 perf_event_ctx_lock_nested(struct perf_event *event, int nesting)
1345 struct perf_event_context *ctx;
1349 ctx = READ_ONCE(event->ctx);
1350 if (!refcount_inc_not_zero(&ctx->refcount)) {
1356 mutex_lock_nested(&ctx->mutex, nesting);
1357 if (event->ctx != ctx) {
1358 mutex_unlock(&ctx->mutex);
1366 static inline struct perf_event_context *
1367 perf_event_ctx_lock(struct perf_event *event)
1369 return perf_event_ctx_lock_nested(event, 0);
1372 static void perf_event_ctx_unlock(struct perf_event *event,
1373 struct perf_event_context *ctx)
1375 mutex_unlock(&ctx->mutex);
1380 * This must be done under the ctx->lock, such as to serialize against
1381 * context_equiv(), therefore we cannot call put_ctx() since that might end up
1382 * calling scheduler related locks and ctx->lock nests inside those.
1384 static __must_check struct perf_event_context *
1385 unclone_ctx(struct perf_event_context *ctx)
1387 struct perf_event_context *parent_ctx = ctx->parent_ctx;
1389 lockdep_assert_held(&ctx->lock);
1392 ctx->parent_ctx = NULL;
1398 static u32 perf_event_pid_type(struct perf_event *event, struct task_struct *p,
1403 * only top level events have the pid namespace they were created in
1406 event = event->parent;
1408 nr = __task_pid_nr_ns(p, type, event->ns);
1409 /* avoid -1 if it is idle thread or runs in another ns */
1410 if (!nr && !pid_alive(p))
1415 static u32 perf_event_pid(struct perf_event *event, struct task_struct *p)
1417 return perf_event_pid_type(event, p, PIDTYPE_TGID);
1420 static u32 perf_event_tid(struct perf_event *event, struct task_struct *p)
1422 return perf_event_pid_type(event, p, PIDTYPE_PID);
1426 * If we inherit events we want to return the parent event id
1429 static u64 primary_event_id(struct perf_event *event)
1434 id = event->parent->id;
1440 * Get the perf_event_context for a task and lock it.
1442 * This has to cope with the fact that until it is locked,
1443 * the context could get moved to another task.
1445 static struct perf_event_context *
1446 perf_lock_task_context(struct task_struct *task, int ctxn, unsigned long *flags)
1448 struct perf_event_context *ctx;
1452 * One of the few rules of preemptible RCU is that one cannot do
1453 * rcu_read_unlock() while holding a scheduler (or nested) lock when
1454 * part of the read side critical section was irqs-enabled -- see
1455 * rcu_read_unlock_special().
1457 * Since ctx->lock nests under rq->lock we must ensure the entire read
1458 * side critical section has interrupts disabled.
1460 local_irq_save(*flags);
1462 ctx = rcu_dereference(task->perf_event_ctxp[ctxn]);
1465 * If this context is a clone of another, it might
1466 * get swapped for another underneath us by
1467 * perf_event_task_sched_out, though the
1468 * rcu_read_lock() protects us from any context
1469 * getting freed. Lock the context and check if it
1470 * got swapped before we could get the lock, and retry
1471 * if so. If we locked the right context, then it
1472 * can't get swapped on us any more.
1474 raw_spin_lock(&ctx->lock);
1475 if (ctx != rcu_dereference(task->perf_event_ctxp[ctxn])) {
1476 raw_spin_unlock(&ctx->lock);
1478 local_irq_restore(*flags);
1482 if (ctx->task == TASK_TOMBSTONE ||
1483 !refcount_inc_not_zero(&ctx->refcount)) {
1484 raw_spin_unlock(&ctx->lock);
1487 WARN_ON_ONCE(ctx->task != task);
1492 local_irq_restore(*flags);
1497 * Get the context for a task and increment its pin_count so it
1498 * can't get swapped to another task. This also increments its
1499 * reference count so that the context can't get freed.
1501 static struct perf_event_context *
1502 perf_pin_task_context(struct task_struct *task, int ctxn)
1504 struct perf_event_context *ctx;
1505 unsigned long flags;
1507 ctx = perf_lock_task_context(task, ctxn, &flags);
1510 raw_spin_unlock_irqrestore(&ctx->lock, flags);
1515 static void perf_unpin_context(struct perf_event_context *ctx)
1517 unsigned long flags;
1519 raw_spin_lock_irqsave(&ctx->lock, flags);
1521 raw_spin_unlock_irqrestore(&ctx->lock, flags);
1525 * Update the record of the current time in a context.
1527 static void update_context_time(struct perf_event_context *ctx)
1529 u64 now = perf_clock();
1531 ctx->time += now - ctx->timestamp;
1532 ctx->timestamp = now;
1535 static u64 perf_event_time(struct perf_event *event)
1537 struct perf_event_context *ctx = event->ctx;
1539 if (is_cgroup_event(event))
1540 return perf_cgroup_event_time(event);
1542 return ctx ? ctx->time : 0;
1545 static enum event_type_t get_event_type(struct perf_event *event)
1547 struct perf_event_context *ctx = event->ctx;
1548 enum event_type_t event_type;
1550 lockdep_assert_held(&ctx->lock);
1553 * It's 'group type', really, because if our group leader is
1554 * pinned, so are we.
1556 if (event->group_leader != event)
1557 event = event->group_leader;
1559 event_type = event->attr.pinned ? EVENT_PINNED : EVENT_FLEXIBLE;
1561 event_type |= EVENT_CPU;
1567 * Helper function to initialize event group nodes.
1569 static void init_event_group(struct perf_event *event)
1571 RB_CLEAR_NODE(&event->group_node);
1572 event->group_index = 0;
1576 * Extract pinned or flexible groups from the context
1577 * based on event attrs bits.
1579 static struct perf_event_groups *
1580 get_event_groups(struct perf_event *event, struct perf_event_context *ctx)
1582 if (event->attr.pinned)
1583 return &ctx->pinned_groups;
1585 return &ctx->flexible_groups;
1589 * Helper function to initializes perf_event_group trees.
1591 static void perf_event_groups_init(struct perf_event_groups *groups)
1593 groups->tree = RB_ROOT;
1597 static inline struct cgroup *event_cgroup(const struct perf_event *event)
1599 struct cgroup *cgroup = NULL;
1601 #ifdef CONFIG_CGROUP_PERF
1603 cgroup = event->cgrp->css.cgroup;
1610 * Compare function for event groups;
1612 * Implements complex key that first sorts by CPU and then by virtual index
1613 * which provides ordering when rotating groups for the same CPU.
1615 static __always_inline int
1616 perf_event_groups_cmp(const int left_cpu, const struct cgroup *left_cgroup,
1617 const u64 left_group_index, const struct perf_event *right)
1619 if (left_cpu < right->cpu)
1621 if (left_cpu > right->cpu)
1624 #ifdef CONFIG_CGROUP_PERF
1626 const struct cgroup *right_cgroup = event_cgroup(right);
1628 if (left_cgroup != right_cgroup) {
1631 * Left has no cgroup but right does, no
1632 * cgroups come first.
1636 if (!right_cgroup) {
1638 * Right has no cgroup but left does, no
1639 * cgroups come first.
1643 /* Two dissimilar cgroups, order by id. */
1644 if (cgroup_id(left_cgroup) < cgroup_id(right_cgroup))
1652 if (left_group_index < right->group_index)
1654 if (left_group_index > right->group_index)
1660 #define __node_2_pe(node) \
1661 rb_entry((node), struct perf_event, group_node)
1663 static inline bool __group_less(struct rb_node *a, const struct rb_node *b)
1665 struct perf_event *e = __node_2_pe(a);
1666 return perf_event_groups_cmp(e->cpu, event_cgroup(e), e->group_index,
1667 __node_2_pe(b)) < 0;
1670 struct __group_key {
1672 struct cgroup *cgroup;
1675 static inline int __group_cmp(const void *key, const struct rb_node *node)
1677 const struct __group_key *a = key;
1678 const struct perf_event *b = __node_2_pe(node);
1680 /* partial/subtree match: @cpu, @cgroup; ignore: @group_index */
1681 return perf_event_groups_cmp(a->cpu, a->cgroup, b->group_index, b);
1685 * Insert @event into @groups' tree; using {@event->cpu, ++@groups->index} for
1686 * key (see perf_event_groups_less). This places it last inside the CPU
1690 perf_event_groups_insert(struct perf_event_groups *groups,
1691 struct perf_event *event)
1693 event->group_index = ++groups->index;
1695 rb_add(&event->group_node, &groups->tree, __group_less);
1699 * Helper function to insert event into the pinned or flexible groups.
1702 add_event_to_groups(struct perf_event *event, struct perf_event_context *ctx)
1704 struct perf_event_groups *groups;
1706 groups = get_event_groups(event, ctx);
1707 perf_event_groups_insert(groups, event);
1711 * Delete a group from a tree.
1714 perf_event_groups_delete(struct perf_event_groups *groups,
1715 struct perf_event *event)
1717 WARN_ON_ONCE(RB_EMPTY_NODE(&event->group_node) ||
1718 RB_EMPTY_ROOT(&groups->tree));
1720 rb_erase(&event->group_node, &groups->tree);
1721 init_event_group(event);
1725 * Helper function to delete event from its groups.
1728 del_event_from_groups(struct perf_event *event, struct perf_event_context *ctx)
1730 struct perf_event_groups *groups;
1732 groups = get_event_groups(event, ctx);
1733 perf_event_groups_delete(groups, event);
1737 * Get the leftmost event in the cpu/cgroup subtree.
1739 static struct perf_event *
1740 perf_event_groups_first(struct perf_event_groups *groups, int cpu,
1741 struct cgroup *cgrp)
1743 struct __group_key key = {
1747 struct rb_node *node;
1749 node = rb_find_first(&key, &groups->tree, __group_cmp);
1751 return __node_2_pe(node);
1757 * Like rb_entry_next_safe() for the @cpu subtree.
1759 static struct perf_event *
1760 perf_event_groups_next(struct perf_event *event)
1762 struct __group_key key = {
1764 .cgroup = event_cgroup(event),
1766 struct rb_node *next;
1768 next = rb_next_match(&key, &event->group_node, __group_cmp);
1770 return __node_2_pe(next);
1776 * Iterate through the whole groups tree.
1778 #define perf_event_groups_for_each(event, groups) \
1779 for (event = rb_entry_safe(rb_first(&((groups)->tree)), \
1780 typeof(*event), group_node); event; \
1781 event = rb_entry_safe(rb_next(&event->group_node), \
1782 typeof(*event), group_node))
1785 * Add an event from the lists for its context.
1786 * Must be called with ctx->mutex and ctx->lock held.
1789 list_add_event(struct perf_event *event, struct perf_event_context *ctx)
1791 lockdep_assert_held(&ctx->lock);
1793 WARN_ON_ONCE(event->attach_state & PERF_ATTACH_CONTEXT);
1794 event->attach_state |= PERF_ATTACH_CONTEXT;
1796 event->tstamp = perf_event_time(event);
1799 * If we're a stand alone event or group leader, we go to the context
1800 * list, group events are kept attached to the group so that
1801 * perf_group_detach can, at all times, locate all siblings.
1803 if (event->group_leader == event) {
1804 event->group_caps = event->event_caps;
1805 add_event_to_groups(event, ctx);
1808 list_add_rcu(&event->event_entry, &ctx->event_list);
1810 if (event->attr.inherit_stat)
1813 if (event->state > PERF_EVENT_STATE_OFF)
1814 perf_cgroup_event_enable(event, ctx);
1820 * Initialize event state based on the perf_event_attr::disabled.
1822 static inline void perf_event__state_init(struct perf_event *event)
1824 event->state = event->attr.disabled ? PERF_EVENT_STATE_OFF :
1825 PERF_EVENT_STATE_INACTIVE;
1828 static void __perf_event_read_size(struct perf_event *event, int nr_siblings)
1830 int entry = sizeof(u64); /* value */
1834 if (event->attr.read_format & PERF_FORMAT_TOTAL_TIME_ENABLED)
1835 size += sizeof(u64);
1837 if (event->attr.read_format & PERF_FORMAT_TOTAL_TIME_RUNNING)
1838 size += sizeof(u64);
1840 if (event->attr.read_format & PERF_FORMAT_ID)
1841 entry += sizeof(u64);
1843 if (event->attr.read_format & PERF_FORMAT_GROUP) {
1845 size += sizeof(u64);
1849 event->read_size = size;
1852 static void __perf_event_header_size(struct perf_event *event, u64 sample_type)
1854 struct perf_sample_data *data;
1857 if (sample_type & PERF_SAMPLE_IP)
1858 size += sizeof(data->ip);
1860 if (sample_type & PERF_SAMPLE_ADDR)
1861 size += sizeof(data->addr);
1863 if (sample_type & PERF_SAMPLE_PERIOD)
1864 size += sizeof(data->period);
1866 if (sample_type & PERF_SAMPLE_WEIGHT_TYPE)
1867 size += sizeof(data->weight.full);
1869 if (sample_type & PERF_SAMPLE_READ)
1870 size += event->read_size;
1872 if (sample_type & PERF_SAMPLE_DATA_SRC)
1873 size += sizeof(data->data_src.val);
1875 if (sample_type & PERF_SAMPLE_TRANSACTION)
1876 size += sizeof(data->txn);
1878 if (sample_type & PERF_SAMPLE_PHYS_ADDR)
1879 size += sizeof(data->phys_addr);
1881 if (sample_type & PERF_SAMPLE_CGROUP)
1882 size += sizeof(data->cgroup);
1884 if (sample_type & PERF_SAMPLE_DATA_PAGE_SIZE)
1885 size += sizeof(data->data_page_size);
1887 if (sample_type & PERF_SAMPLE_CODE_PAGE_SIZE)
1888 size += sizeof(data->code_page_size);
1890 event->header_size = size;
1894 * Called at perf_event creation and when events are attached/detached from a
1897 static void perf_event__header_size(struct perf_event *event)
1899 __perf_event_read_size(event,
1900 event->group_leader->nr_siblings);
1901 __perf_event_header_size(event, event->attr.sample_type);
1904 static void perf_event__id_header_size(struct perf_event *event)
1906 struct perf_sample_data *data;
1907 u64 sample_type = event->attr.sample_type;
1910 if (sample_type & PERF_SAMPLE_TID)
1911 size += sizeof(data->tid_entry);
1913 if (sample_type & PERF_SAMPLE_TIME)
1914 size += sizeof(data->time);
1916 if (sample_type & PERF_SAMPLE_IDENTIFIER)
1917 size += sizeof(data->id);
1919 if (sample_type & PERF_SAMPLE_ID)
1920 size += sizeof(data->id);
1922 if (sample_type & PERF_SAMPLE_STREAM_ID)
1923 size += sizeof(data->stream_id);
1925 if (sample_type & PERF_SAMPLE_CPU)
1926 size += sizeof(data->cpu_entry);
1928 event->id_header_size = size;
1931 static bool perf_event_validate_size(struct perf_event *event)
1934 * The values computed here will be over-written when we actually
1937 __perf_event_read_size(event, event->group_leader->nr_siblings + 1);
1938 __perf_event_header_size(event, event->attr.sample_type & ~PERF_SAMPLE_READ);
1939 perf_event__id_header_size(event);
1942 * Sum the lot; should not exceed the 64k limit we have on records.
1943 * Conservative limit to allow for callchains and other variable fields.
1945 if (event->read_size + event->header_size +
1946 event->id_header_size + sizeof(struct perf_event_header) >= 16*1024)
1952 static void perf_group_attach(struct perf_event *event)
1954 struct perf_event *group_leader = event->group_leader, *pos;
1956 lockdep_assert_held(&event->ctx->lock);
1959 * We can have double attach due to group movement in perf_event_open.
1961 if (event->attach_state & PERF_ATTACH_GROUP)
1964 event->attach_state |= PERF_ATTACH_GROUP;
1966 if (group_leader == event)
1969 WARN_ON_ONCE(group_leader->ctx != event->ctx);
1971 group_leader->group_caps &= event->event_caps;
1973 list_add_tail(&event->sibling_list, &group_leader->sibling_list);
1974 group_leader->nr_siblings++;
1976 perf_event__header_size(group_leader);
1978 for_each_sibling_event(pos, group_leader)
1979 perf_event__header_size(pos);
1983 * Remove an event from the lists for its context.
1984 * Must be called with ctx->mutex and ctx->lock held.
1987 list_del_event(struct perf_event *event, struct perf_event_context *ctx)
1989 WARN_ON_ONCE(event->ctx != ctx);
1990 lockdep_assert_held(&ctx->lock);
1993 * We can have double detach due to exit/hot-unplug + close.
1995 if (!(event->attach_state & PERF_ATTACH_CONTEXT))
1998 event->attach_state &= ~PERF_ATTACH_CONTEXT;
2001 if (event->attr.inherit_stat)
2004 list_del_rcu(&event->event_entry);
2006 if (event->group_leader == event)
2007 del_event_from_groups(event, ctx);
2010 * If event was in error state, then keep it
2011 * that way, otherwise bogus counts will be
2012 * returned on read(). The only way to get out
2013 * of error state is by explicit re-enabling
2016 if (event->state > PERF_EVENT_STATE_OFF) {
2017 perf_cgroup_event_disable(event, ctx);
2018 perf_event_set_state(event, PERF_EVENT_STATE_OFF);
2025 perf_aux_output_match(struct perf_event *event, struct perf_event *aux_event)
2027 if (!has_aux(aux_event))
2030 if (!event->pmu->aux_output_match)
2033 return event->pmu->aux_output_match(aux_event);
2036 static void put_event(struct perf_event *event);
2037 static void event_sched_out(struct perf_event *event,
2038 struct perf_cpu_context *cpuctx,
2039 struct perf_event_context *ctx);
2041 static void perf_put_aux_event(struct perf_event *event)
2043 struct perf_event_context *ctx = event->ctx;
2044 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
2045 struct perf_event *iter;
2048 * If event uses aux_event tear down the link
2050 if (event->aux_event) {
2051 iter = event->aux_event;
2052 event->aux_event = NULL;
2058 * If the event is an aux_event, tear down all links to
2059 * it from other events.
2061 for_each_sibling_event(iter, event->group_leader) {
2062 if (iter->aux_event != event)
2065 iter->aux_event = NULL;
2069 * If it's ACTIVE, schedule it out and put it into ERROR
2070 * state so that we don't try to schedule it again. Note
2071 * that perf_event_enable() will clear the ERROR status.
2073 event_sched_out(iter, cpuctx, ctx);
2074 perf_event_set_state(event, PERF_EVENT_STATE_ERROR);
2078 static bool perf_need_aux_event(struct perf_event *event)
2080 return !!event->attr.aux_output || !!event->attr.aux_sample_size;
2083 static int perf_get_aux_event(struct perf_event *event,
2084 struct perf_event *group_leader)
2087 * Our group leader must be an aux event if we want to be
2088 * an aux_output. This way, the aux event will precede its
2089 * aux_output events in the group, and therefore will always
2096 * aux_output and aux_sample_size are mutually exclusive.
2098 if (event->attr.aux_output && event->attr.aux_sample_size)
2101 if (event->attr.aux_output &&
2102 !perf_aux_output_match(event, group_leader))
2105 if (event->attr.aux_sample_size && !group_leader->pmu->snapshot_aux)
2108 if (!atomic_long_inc_not_zero(&group_leader->refcount))
2112 * Link aux_outputs to their aux event; this is undone in
2113 * perf_group_detach() by perf_put_aux_event(). When the
2114 * group in torn down, the aux_output events loose their
2115 * link to the aux_event and can't schedule any more.
2117 event->aux_event = group_leader;
2122 static inline struct list_head *get_event_list(struct perf_event *event)
2124 struct perf_event_context *ctx = event->ctx;
2125 return event->attr.pinned ? &ctx->pinned_active : &ctx->flexible_active;
2129 * Events that have PERF_EV_CAP_SIBLING require being part of a group and
2130 * cannot exist on their own, schedule them out and move them into the ERROR
2131 * state. Also see _perf_event_enable(), it will not be able to recover
2134 static inline void perf_remove_sibling_event(struct perf_event *event)
2136 struct perf_event_context *ctx = event->ctx;
2137 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
2139 event_sched_out(event, cpuctx, ctx);
2140 perf_event_set_state(event, PERF_EVENT_STATE_ERROR);
2143 static void perf_group_detach(struct perf_event *event)
2145 struct perf_event *leader = event->group_leader;
2146 struct perf_event *sibling, *tmp;
2147 struct perf_event_context *ctx = event->ctx;
2149 lockdep_assert_held(&ctx->lock);
2152 * We can have double detach due to exit/hot-unplug + close.
2154 if (!(event->attach_state & PERF_ATTACH_GROUP))
2157 event->attach_state &= ~PERF_ATTACH_GROUP;
2159 perf_put_aux_event(event);
2162 * If this is a sibling, remove it from its group.
2164 if (leader != event) {
2165 list_del_init(&event->sibling_list);
2166 event->group_leader->nr_siblings--;
2171 * If this was a group event with sibling events then
2172 * upgrade the siblings to singleton events by adding them
2173 * to whatever list we are on.
2175 list_for_each_entry_safe(sibling, tmp, &event->sibling_list, sibling_list) {
2177 if (sibling->event_caps & PERF_EV_CAP_SIBLING)
2178 perf_remove_sibling_event(sibling);
2180 sibling->group_leader = sibling;
2181 list_del_init(&sibling->sibling_list);
2183 /* Inherit group flags from the previous leader */
2184 sibling->group_caps = event->group_caps;
2186 if (!RB_EMPTY_NODE(&event->group_node)) {
2187 add_event_to_groups(sibling, event->ctx);
2189 if (sibling->state == PERF_EVENT_STATE_ACTIVE)
2190 list_add_tail(&sibling->active_list, get_event_list(sibling));
2193 WARN_ON_ONCE(sibling->ctx != event->ctx);
2197 for_each_sibling_event(tmp, leader)
2198 perf_event__header_size(tmp);
2200 perf_event__header_size(leader);
2203 static void sync_child_event(struct perf_event *child_event);
2205 static void perf_child_detach(struct perf_event *event)
2207 struct perf_event *parent_event = event->parent;
2209 if (!(event->attach_state & PERF_ATTACH_CHILD))
2212 event->attach_state &= ~PERF_ATTACH_CHILD;
2214 if (WARN_ON_ONCE(!parent_event))
2217 lockdep_assert_held(&parent_event->child_mutex);
2219 sync_child_event(event);
2220 list_del_init(&event->child_list);
2223 static bool is_orphaned_event(struct perf_event *event)
2225 return event->state == PERF_EVENT_STATE_DEAD;
2228 static inline int __pmu_filter_match(struct perf_event *event)
2230 struct pmu *pmu = event->pmu;
2231 return pmu->filter_match ? pmu->filter_match(event) : 1;
2235 * Check whether we should attempt to schedule an event group based on
2236 * PMU-specific filtering. An event group can consist of HW and SW events,
2237 * potentially with a SW leader, so we must check all the filters, to
2238 * determine whether a group is schedulable:
2240 static inline int pmu_filter_match(struct perf_event *event)
2242 struct perf_event *sibling;
2244 if (!__pmu_filter_match(event))
2247 for_each_sibling_event(sibling, event) {
2248 if (!__pmu_filter_match(sibling))
2256 event_filter_match(struct perf_event *event)
2258 return (event->cpu == -1 || event->cpu == smp_processor_id()) &&
2259 perf_cgroup_match(event) && pmu_filter_match(event);
2263 event_sched_out(struct perf_event *event,
2264 struct perf_cpu_context *cpuctx,
2265 struct perf_event_context *ctx)
2267 enum perf_event_state state = PERF_EVENT_STATE_INACTIVE;
2269 WARN_ON_ONCE(event->ctx != ctx);
2270 lockdep_assert_held(&ctx->lock);
2272 if (event->state != PERF_EVENT_STATE_ACTIVE)
2276 * Asymmetry; we only schedule events _IN_ through ctx_sched_in(), but
2277 * we can schedule events _OUT_ individually through things like
2278 * __perf_remove_from_context().
2280 list_del_init(&event->active_list);
2282 perf_pmu_disable(event->pmu);
2284 event->pmu->del(event, 0);
2287 if (READ_ONCE(event->pending_disable) >= 0) {
2288 WRITE_ONCE(event->pending_disable, -1);
2289 perf_cgroup_event_disable(event, ctx);
2290 state = PERF_EVENT_STATE_OFF;
2292 perf_event_set_state(event, state);
2294 if (!is_software_event(event))
2295 cpuctx->active_oncpu--;
2296 if (!--ctx->nr_active)
2297 perf_event_ctx_deactivate(ctx);
2298 if (event->attr.freq && event->attr.sample_freq)
2300 if (event->attr.exclusive || !cpuctx->active_oncpu)
2301 cpuctx->exclusive = 0;
2303 perf_pmu_enable(event->pmu);
2307 group_sched_out(struct perf_event *group_event,
2308 struct perf_cpu_context *cpuctx,
2309 struct perf_event_context *ctx)
2311 struct perf_event *event;
2313 if (group_event->state != PERF_EVENT_STATE_ACTIVE)
2316 perf_pmu_disable(ctx->pmu);
2318 event_sched_out(group_event, cpuctx, ctx);
2321 * Schedule out siblings (if any):
2323 for_each_sibling_event(event, group_event)
2324 event_sched_out(event, cpuctx, ctx);
2326 perf_pmu_enable(ctx->pmu);
2329 #define DETACH_GROUP 0x01UL
2330 #define DETACH_CHILD 0x02UL
2333 * Cross CPU call to remove a performance event
2335 * We disable the event on the hardware level first. After that we
2336 * remove it from the context list.
2339 __perf_remove_from_context(struct perf_event *event,
2340 struct perf_cpu_context *cpuctx,
2341 struct perf_event_context *ctx,
2344 unsigned long flags = (unsigned long)info;
2346 if (ctx->is_active & EVENT_TIME) {
2347 update_context_time(ctx);
2348 update_cgrp_time_from_cpuctx(cpuctx);
2351 event_sched_out(event, cpuctx, ctx);
2352 if (flags & DETACH_GROUP)
2353 perf_group_detach(event);
2354 if (flags & DETACH_CHILD)
2355 perf_child_detach(event);
2356 list_del_event(event, ctx);
2358 if (!ctx->nr_events && ctx->is_active) {
2360 ctx->rotate_necessary = 0;
2362 WARN_ON_ONCE(cpuctx->task_ctx != ctx);
2363 cpuctx->task_ctx = NULL;
2369 * Remove the event from a task's (or a CPU's) list of events.
2371 * If event->ctx is a cloned context, callers must make sure that
2372 * every task struct that event->ctx->task could possibly point to
2373 * remains valid. This is OK when called from perf_release since
2374 * that only calls us on the top-level context, which can't be a clone.
2375 * When called from perf_event_exit_task, it's OK because the
2376 * context has been detached from its task.
2378 static void perf_remove_from_context(struct perf_event *event, unsigned long flags)
2380 struct perf_event_context *ctx = event->ctx;
2382 lockdep_assert_held(&ctx->mutex);
2385 * Because of perf_event_exit_task(), perf_remove_from_context() ought
2386 * to work in the face of TASK_TOMBSTONE, unlike every other
2387 * event_function_call() user.
2389 raw_spin_lock_irq(&ctx->lock);
2390 if (!ctx->is_active) {
2391 __perf_remove_from_context(event, __get_cpu_context(ctx),
2392 ctx, (void *)flags);
2393 raw_spin_unlock_irq(&ctx->lock);
2396 raw_spin_unlock_irq(&ctx->lock);
2398 event_function_call(event, __perf_remove_from_context, (void *)flags);
2402 * Cross CPU call to disable a performance event
2404 static void __perf_event_disable(struct perf_event *event,
2405 struct perf_cpu_context *cpuctx,
2406 struct perf_event_context *ctx,
2409 if (event->state < PERF_EVENT_STATE_INACTIVE)
2412 if (ctx->is_active & EVENT_TIME) {
2413 update_context_time(ctx);
2414 update_cgrp_time_from_event(event);
2417 if (event == event->group_leader)
2418 group_sched_out(event, cpuctx, ctx);
2420 event_sched_out(event, cpuctx, ctx);
2422 perf_event_set_state(event, PERF_EVENT_STATE_OFF);
2423 perf_cgroup_event_disable(event, ctx);
2429 * If event->ctx is a cloned context, callers must make sure that
2430 * every task struct that event->ctx->task could possibly point to
2431 * remains valid. This condition is satisfied when called through
2432 * perf_event_for_each_child or perf_event_for_each because they
2433 * hold the top-level event's child_mutex, so any descendant that
2434 * goes to exit will block in perf_event_exit_event().
2436 * When called from perf_pending_event it's OK because event->ctx
2437 * is the current context on this CPU and preemption is disabled,
2438 * hence we can't get into perf_event_task_sched_out for this context.
2440 static void _perf_event_disable(struct perf_event *event)
2442 struct perf_event_context *ctx = event->ctx;
2444 raw_spin_lock_irq(&ctx->lock);
2445 if (event->state <= PERF_EVENT_STATE_OFF) {
2446 raw_spin_unlock_irq(&ctx->lock);
2449 raw_spin_unlock_irq(&ctx->lock);
2451 event_function_call(event, __perf_event_disable, NULL);
2454 void perf_event_disable_local(struct perf_event *event)
2456 event_function_local(event, __perf_event_disable, NULL);
2460 * Strictly speaking kernel users cannot create groups and therefore this
2461 * interface does not need the perf_event_ctx_lock() magic.
2463 void perf_event_disable(struct perf_event *event)
2465 struct perf_event_context *ctx;
2467 ctx = perf_event_ctx_lock(event);
2468 _perf_event_disable(event);
2469 perf_event_ctx_unlock(event, ctx);
2471 EXPORT_SYMBOL_GPL(perf_event_disable);
2473 void perf_event_disable_inatomic(struct perf_event *event)
2475 WRITE_ONCE(event->pending_disable, smp_processor_id());
2476 /* can fail, see perf_pending_event_disable() */
2477 irq_work_queue(&event->pending);
2480 static void perf_set_shadow_time(struct perf_event *event,
2481 struct perf_event_context *ctx)
2484 * use the correct time source for the time snapshot
2486 * We could get by without this by leveraging the
2487 * fact that to get to this function, the caller
2488 * has most likely already called update_context_time()
2489 * and update_cgrp_time_xx() and thus both timestamp
2490 * are identical (or very close). Given that tstamp is,
2491 * already adjusted for cgroup, we could say that:
2492 * tstamp - ctx->timestamp
2494 * tstamp - cgrp->timestamp.
2496 * Then, in perf_output_read(), the calculation would
2497 * work with no changes because:
2498 * - event is guaranteed scheduled in
2499 * - no scheduled out in between
2500 * - thus the timestamp would be the same
2502 * But this is a bit hairy.
2504 * So instead, we have an explicit cgroup call to remain
2505 * within the time source all along. We believe it
2506 * is cleaner and simpler to understand.
2508 if (is_cgroup_event(event))
2509 perf_cgroup_set_shadow_time(event, event->tstamp);
2511 event->shadow_ctx_time = event->tstamp - ctx->timestamp;
2514 #define MAX_INTERRUPTS (~0ULL)
2516 static void perf_log_throttle(struct perf_event *event, int enable);
2517 static void perf_log_itrace_start(struct perf_event *event);
2520 event_sched_in(struct perf_event *event,
2521 struct perf_cpu_context *cpuctx,
2522 struct perf_event_context *ctx)
2526 WARN_ON_ONCE(event->ctx != ctx);
2528 lockdep_assert_held(&ctx->lock);
2530 if (event->state <= PERF_EVENT_STATE_OFF)
2533 WRITE_ONCE(event->oncpu, smp_processor_id());
2535 * Order event::oncpu write to happen before the ACTIVE state is
2536 * visible. This allows perf_event_{stop,read}() to observe the correct
2537 * ->oncpu if it sees ACTIVE.
2540 perf_event_set_state(event, PERF_EVENT_STATE_ACTIVE);
2543 * Unthrottle events, since we scheduled we might have missed several
2544 * ticks already, also for a heavily scheduling task there is little
2545 * guarantee it'll get a tick in a timely manner.
2547 if (unlikely(event->hw.interrupts == MAX_INTERRUPTS)) {
2548 perf_log_throttle(event, 1);
2549 event->hw.interrupts = 0;
2552 perf_pmu_disable(event->pmu);
2554 perf_set_shadow_time(event, ctx);
2556 perf_log_itrace_start(event);
2558 if (event->pmu->add(event, PERF_EF_START)) {
2559 perf_event_set_state(event, PERF_EVENT_STATE_INACTIVE);
2565 if (!is_software_event(event))
2566 cpuctx->active_oncpu++;
2567 if (!ctx->nr_active++)
2568 perf_event_ctx_activate(ctx);
2569 if (event->attr.freq && event->attr.sample_freq)
2572 if (event->attr.exclusive)
2573 cpuctx->exclusive = 1;
2576 perf_pmu_enable(event->pmu);
2582 group_sched_in(struct perf_event *group_event,
2583 struct perf_cpu_context *cpuctx,
2584 struct perf_event_context *ctx)
2586 struct perf_event *event, *partial_group = NULL;
2587 struct pmu *pmu = ctx->pmu;
2589 if (group_event->state == PERF_EVENT_STATE_OFF)
2592 pmu->start_txn(pmu, PERF_PMU_TXN_ADD);
2594 if (event_sched_in(group_event, cpuctx, ctx))
2598 * Schedule in siblings as one group (if any):
2600 for_each_sibling_event(event, group_event) {
2601 if (event_sched_in(event, cpuctx, ctx)) {
2602 partial_group = event;
2607 if (!pmu->commit_txn(pmu))
2612 * Groups can be scheduled in as one unit only, so undo any
2613 * partial group before returning:
2614 * The events up to the failed event are scheduled out normally.
2616 for_each_sibling_event(event, group_event) {
2617 if (event == partial_group)
2620 event_sched_out(event, cpuctx, ctx);
2622 event_sched_out(group_event, cpuctx, ctx);
2625 pmu->cancel_txn(pmu);
2630 * Work out whether we can put this event group on the CPU now.
2632 static int group_can_go_on(struct perf_event *event,
2633 struct perf_cpu_context *cpuctx,
2637 * Groups consisting entirely of software events can always go on.
2639 if (event->group_caps & PERF_EV_CAP_SOFTWARE)
2642 * If an exclusive group is already on, no other hardware
2645 if (cpuctx->exclusive)
2648 * If this group is exclusive and there are already
2649 * events on the CPU, it can't go on.
2651 if (event->attr.exclusive && !list_empty(get_event_list(event)))
2654 * Otherwise, try to add it if all previous groups were able
2660 static void add_event_to_ctx(struct perf_event *event,
2661 struct perf_event_context *ctx)
2663 list_add_event(event, ctx);
2664 perf_group_attach(event);
2667 static void ctx_sched_out(struct perf_event_context *ctx,
2668 struct perf_cpu_context *cpuctx,
2669 enum event_type_t event_type);
2671 ctx_sched_in(struct perf_event_context *ctx,
2672 struct perf_cpu_context *cpuctx,
2673 enum event_type_t event_type,
2674 struct task_struct *task);
2676 static void task_ctx_sched_out(struct perf_cpu_context *cpuctx,
2677 struct perf_event_context *ctx,
2678 enum event_type_t event_type)
2680 if (!cpuctx->task_ctx)
2683 if (WARN_ON_ONCE(ctx != cpuctx->task_ctx))
2686 ctx_sched_out(ctx, cpuctx, event_type);
2689 static void perf_event_sched_in(struct perf_cpu_context *cpuctx,
2690 struct perf_event_context *ctx,
2691 struct task_struct *task)
2693 cpu_ctx_sched_in(cpuctx, EVENT_PINNED, task);
2695 ctx_sched_in(ctx, cpuctx, EVENT_PINNED, task);
2696 cpu_ctx_sched_in(cpuctx, EVENT_FLEXIBLE, task);
2698 ctx_sched_in(ctx, cpuctx, EVENT_FLEXIBLE, task);
2702 * We want to maintain the following priority of scheduling:
2703 * - CPU pinned (EVENT_CPU | EVENT_PINNED)
2704 * - task pinned (EVENT_PINNED)
2705 * - CPU flexible (EVENT_CPU | EVENT_FLEXIBLE)
2706 * - task flexible (EVENT_FLEXIBLE).
2708 * In order to avoid unscheduling and scheduling back in everything every
2709 * time an event is added, only do it for the groups of equal priority and
2712 * This can be called after a batch operation on task events, in which case
2713 * event_type is a bit mask of the types of events involved. For CPU events,
2714 * event_type is only either EVENT_PINNED or EVENT_FLEXIBLE.
2716 static void ctx_resched(struct perf_cpu_context *cpuctx,
2717 struct perf_event_context *task_ctx,
2718 enum event_type_t event_type)
2720 enum event_type_t ctx_event_type;
2721 bool cpu_event = !!(event_type & EVENT_CPU);
2724 * If pinned groups are involved, flexible groups also need to be
2727 if (event_type & EVENT_PINNED)
2728 event_type |= EVENT_FLEXIBLE;
2730 ctx_event_type = event_type & EVENT_ALL;
2732 perf_pmu_disable(cpuctx->ctx.pmu);
2734 task_ctx_sched_out(cpuctx, task_ctx, event_type);
2737 * Decide which cpu ctx groups to schedule out based on the types
2738 * of events that caused rescheduling:
2739 * - EVENT_CPU: schedule out corresponding groups;
2740 * - EVENT_PINNED task events: schedule out EVENT_FLEXIBLE groups;
2741 * - otherwise, do nothing more.
2744 cpu_ctx_sched_out(cpuctx, ctx_event_type);
2745 else if (ctx_event_type & EVENT_PINNED)
2746 cpu_ctx_sched_out(cpuctx, EVENT_FLEXIBLE);
2748 perf_event_sched_in(cpuctx, task_ctx, current);
2749 perf_pmu_enable(cpuctx->ctx.pmu);
2752 void perf_pmu_resched(struct pmu *pmu)
2754 struct perf_cpu_context *cpuctx = this_cpu_ptr(pmu->pmu_cpu_context);
2755 struct perf_event_context *task_ctx = cpuctx->task_ctx;
2757 perf_ctx_lock(cpuctx, task_ctx);
2758 ctx_resched(cpuctx, task_ctx, EVENT_ALL|EVENT_CPU);
2759 perf_ctx_unlock(cpuctx, task_ctx);
2763 * Cross CPU call to install and enable a performance event
2765 * Very similar to remote_function() + event_function() but cannot assume that
2766 * things like ctx->is_active and cpuctx->task_ctx are set.
2768 static int __perf_install_in_context(void *info)
2770 struct perf_event *event = info;
2771 struct perf_event_context *ctx = event->ctx;
2772 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
2773 struct perf_event_context *task_ctx = cpuctx->task_ctx;
2774 bool reprogram = true;
2777 raw_spin_lock(&cpuctx->ctx.lock);
2779 raw_spin_lock(&ctx->lock);
2782 reprogram = (ctx->task == current);
2785 * If the task is running, it must be running on this CPU,
2786 * otherwise we cannot reprogram things.
2788 * If its not running, we don't care, ctx->lock will
2789 * serialize against it becoming runnable.
2791 if (task_curr(ctx->task) && !reprogram) {
2796 WARN_ON_ONCE(reprogram && cpuctx->task_ctx && cpuctx->task_ctx != ctx);
2797 } else if (task_ctx) {
2798 raw_spin_lock(&task_ctx->lock);
2801 #ifdef CONFIG_CGROUP_PERF
2802 if (event->state > PERF_EVENT_STATE_OFF && is_cgroup_event(event)) {
2804 * If the current cgroup doesn't match the event's
2805 * cgroup, we should not try to schedule it.
2807 struct perf_cgroup *cgrp = perf_cgroup_from_task(current, ctx);
2808 reprogram = cgroup_is_descendant(cgrp->css.cgroup,
2809 event->cgrp->css.cgroup);
2814 ctx_sched_out(ctx, cpuctx, EVENT_TIME);
2815 add_event_to_ctx(event, ctx);
2816 ctx_resched(cpuctx, task_ctx, get_event_type(event));
2818 add_event_to_ctx(event, ctx);
2822 perf_ctx_unlock(cpuctx, task_ctx);
2827 static bool exclusive_event_installable(struct perf_event *event,
2828 struct perf_event_context *ctx);
2831 * Attach a performance event to a context.
2833 * Very similar to event_function_call, see comment there.
2836 perf_install_in_context(struct perf_event_context *ctx,
2837 struct perf_event *event,
2840 struct task_struct *task = READ_ONCE(ctx->task);
2842 lockdep_assert_held(&ctx->mutex);
2844 WARN_ON_ONCE(!exclusive_event_installable(event, ctx));
2846 if (event->cpu != -1)
2850 * Ensures that if we can observe event->ctx, both the event and ctx
2851 * will be 'complete'. See perf_iterate_sb_cpu().
2853 smp_store_release(&event->ctx, ctx);
2856 * perf_event_attr::disabled events will not run and can be initialized
2857 * without IPI. Except when this is the first event for the context, in
2858 * that case we need the magic of the IPI to set ctx->is_active.
2860 * The IOC_ENABLE that is sure to follow the creation of a disabled
2861 * event will issue the IPI and reprogram the hardware.
2863 if (__perf_effective_state(event) == PERF_EVENT_STATE_OFF && ctx->nr_events) {
2864 raw_spin_lock_irq(&ctx->lock);
2865 if (ctx->task == TASK_TOMBSTONE) {
2866 raw_spin_unlock_irq(&ctx->lock);
2869 add_event_to_ctx(event, ctx);
2870 raw_spin_unlock_irq(&ctx->lock);
2875 cpu_function_call(cpu, __perf_install_in_context, event);
2880 * Should not happen, we validate the ctx is still alive before calling.
2882 if (WARN_ON_ONCE(task == TASK_TOMBSTONE))
2886 * Installing events is tricky because we cannot rely on ctx->is_active
2887 * to be set in case this is the nr_events 0 -> 1 transition.
2889 * Instead we use task_curr(), which tells us if the task is running.
2890 * However, since we use task_curr() outside of rq::lock, we can race
2891 * against the actual state. This means the result can be wrong.
2893 * If we get a false positive, we retry, this is harmless.
2895 * If we get a false negative, things are complicated. If we are after
2896 * perf_event_context_sched_in() ctx::lock will serialize us, and the
2897 * value must be correct. If we're before, it doesn't matter since
2898 * perf_event_context_sched_in() will program the counter.
2900 * However, this hinges on the remote context switch having observed
2901 * our task->perf_event_ctxp[] store, such that it will in fact take
2902 * ctx::lock in perf_event_context_sched_in().
2904 * We do this by task_function_call(), if the IPI fails to hit the task
2905 * we know any future context switch of task must see the
2906 * perf_event_ctpx[] store.
2910 * This smp_mb() orders the task->perf_event_ctxp[] store with the
2911 * task_cpu() load, such that if the IPI then does not find the task
2912 * running, a future context switch of that task must observe the
2917 if (!task_function_call(task, __perf_install_in_context, event))
2920 raw_spin_lock_irq(&ctx->lock);
2922 if (WARN_ON_ONCE(task == TASK_TOMBSTONE)) {
2924 * Cannot happen because we already checked above (which also
2925 * cannot happen), and we hold ctx->mutex, which serializes us
2926 * against perf_event_exit_task_context().
2928 raw_spin_unlock_irq(&ctx->lock);
2932 * If the task is not running, ctx->lock will avoid it becoming so,
2933 * thus we can safely install the event.
2935 if (task_curr(task)) {
2936 raw_spin_unlock_irq(&ctx->lock);
2939 add_event_to_ctx(event, ctx);
2940 raw_spin_unlock_irq(&ctx->lock);
2944 * Cross CPU call to enable a performance event
2946 static void __perf_event_enable(struct perf_event *event,
2947 struct perf_cpu_context *cpuctx,
2948 struct perf_event_context *ctx,
2951 struct perf_event *leader = event->group_leader;
2952 struct perf_event_context *task_ctx;
2954 if (event->state >= PERF_EVENT_STATE_INACTIVE ||
2955 event->state <= PERF_EVENT_STATE_ERROR)
2959 ctx_sched_out(ctx, cpuctx, EVENT_TIME);
2961 perf_event_set_state(event, PERF_EVENT_STATE_INACTIVE);
2962 perf_cgroup_event_enable(event, ctx);
2964 if (!ctx->is_active)
2967 if (!event_filter_match(event)) {
2968 ctx_sched_in(ctx, cpuctx, EVENT_TIME, current);
2973 * If the event is in a group and isn't the group leader,
2974 * then don't put it on unless the group is on.
2976 if (leader != event && leader->state != PERF_EVENT_STATE_ACTIVE) {
2977 ctx_sched_in(ctx, cpuctx, EVENT_TIME, current);
2981 task_ctx = cpuctx->task_ctx;
2983 WARN_ON_ONCE(task_ctx != ctx);
2985 ctx_resched(cpuctx, task_ctx, get_event_type(event));
2991 * If event->ctx is a cloned context, callers must make sure that
2992 * every task struct that event->ctx->task could possibly point to
2993 * remains valid. This condition is satisfied when called through
2994 * perf_event_for_each_child or perf_event_for_each as described
2995 * for perf_event_disable.
2997 static void _perf_event_enable(struct perf_event *event)
2999 struct perf_event_context *ctx = event->ctx;
3001 raw_spin_lock_irq(&ctx->lock);
3002 if (event->state >= PERF_EVENT_STATE_INACTIVE ||
3003 event->state < PERF_EVENT_STATE_ERROR) {
3005 raw_spin_unlock_irq(&ctx->lock);
3010 * If the event is in error state, clear that first.
3012 * That way, if we see the event in error state below, we know that it
3013 * has gone back into error state, as distinct from the task having
3014 * been scheduled away before the cross-call arrived.
3016 if (event->state == PERF_EVENT_STATE_ERROR) {
3018 * Detached SIBLING events cannot leave ERROR state.
3020 if (event->event_caps & PERF_EV_CAP_SIBLING &&
3021 event->group_leader == event)
3024 event->state = PERF_EVENT_STATE_OFF;
3026 raw_spin_unlock_irq(&ctx->lock);
3028 event_function_call(event, __perf_event_enable, NULL);
3032 * See perf_event_disable();
3034 void perf_event_enable(struct perf_event *event)
3036 struct perf_event_context *ctx;
3038 ctx = perf_event_ctx_lock(event);
3039 _perf_event_enable(event);
3040 perf_event_ctx_unlock(event, ctx);
3042 EXPORT_SYMBOL_GPL(perf_event_enable);
3044 struct stop_event_data {
3045 struct perf_event *event;
3046 unsigned int restart;
3049 static int __perf_event_stop(void *info)
3051 struct stop_event_data *sd = info;
3052 struct perf_event *event = sd->event;
3054 /* if it's already INACTIVE, do nothing */
3055 if (READ_ONCE(event->state) != PERF_EVENT_STATE_ACTIVE)
3058 /* matches smp_wmb() in event_sched_in() */
3062 * There is a window with interrupts enabled before we get here,
3063 * so we need to check again lest we try to stop another CPU's event.
3065 if (READ_ONCE(event->oncpu) != smp_processor_id())
3068 event->pmu->stop(event, PERF_EF_UPDATE);
3071 * May race with the actual stop (through perf_pmu_output_stop()),
3072 * but it is only used for events with AUX ring buffer, and such
3073 * events will refuse to restart because of rb::aux_mmap_count==0,
3074 * see comments in perf_aux_output_begin().
3076 * Since this is happening on an event-local CPU, no trace is lost
3080 event->pmu->start(event, 0);
3085 static int perf_event_stop(struct perf_event *event, int restart)
3087 struct stop_event_data sd = {
3094 if (READ_ONCE(event->state) != PERF_EVENT_STATE_ACTIVE)
3097 /* matches smp_wmb() in event_sched_in() */
3101 * We only want to restart ACTIVE events, so if the event goes
3102 * inactive here (event->oncpu==-1), there's nothing more to do;
3103 * fall through with ret==-ENXIO.
3105 ret = cpu_function_call(READ_ONCE(event->oncpu),
3106 __perf_event_stop, &sd);
3107 } while (ret == -EAGAIN);
3113 * In order to contain the amount of racy and tricky in the address filter
3114 * configuration management, it is a two part process:
3116 * (p1) when userspace mappings change as a result of (1) or (2) or (3) below,
3117 * we update the addresses of corresponding vmas in
3118 * event::addr_filter_ranges array and bump the event::addr_filters_gen;
3119 * (p2) when an event is scheduled in (pmu::add), it calls
3120 * perf_event_addr_filters_sync() which calls pmu::addr_filters_sync()
3121 * if the generation has changed since the previous call.
3123 * If (p1) happens while the event is active, we restart it to force (p2).
3125 * (1) perf_addr_filters_apply(): adjusting filters' offsets based on
3126 * pre-existing mappings, called once when new filters arrive via SET_FILTER
3128 * (2) perf_addr_filters_adjust(): adjusting filters' offsets based on newly
3129 * registered mapping, called for every new mmap(), with mm::mmap_lock down
3131 * (3) perf_event_addr_filters_exec(): clearing filters' offsets in the process
3134 void perf_event_addr_filters_sync(struct perf_event *event)
3136 struct perf_addr_filters_head *ifh = perf_event_addr_filters(event);
3138 if (!has_addr_filter(event))
3141 raw_spin_lock(&ifh->lock);
3142 if (event->addr_filters_gen != event->hw.addr_filters_gen) {
3143 event->pmu->addr_filters_sync(event);
3144 event->hw.addr_filters_gen = event->addr_filters_gen;
3146 raw_spin_unlock(&ifh->lock);
3148 EXPORT_SYMBOL_GPL(perf_event_addr_filters_sync);
3150 static int _perf_event_refresh(struct perf_event *event, int refresh)
3153 * not supported on inherited events
3155 if (event->attr.inherit || !is_sampling_event(event))
3158 atomic_add(refresh, &event->event_limit);
3159 _perf_event_enable(event);
3165 * See perf_event_disable()
3167 int perf_event_refresh(struct perf_event *event, int refresh)
3169 struct perf_event_context *ctx;
3172 ctx = perf_event_ctx_lock(event);
3173 ret = _perf_event_refresh(event, refresh);
3174 perf_event_ctx_unlock(event, ctx);
3178 EXPORT_SYMBOL_GPL(perf_event_refresh);
3180 static int perf_event_modify_breakpoint(struct perf_event *bp,
3181 struct perf_event_attr *attr)
3185 _perf_event_disable(bp);
3187 err = modify_user_hw_breakpoint_check(bp, attr, true);
3189 if (!bp->attr.disabled)
3190 _perf_event_enable(bp);
3195 static int perf_event_modify_attr(struct perf_event *event,
3196 struct perf_event_attr *attr)
3198 int (*func)(struct perf_event *, struct perf_event_attr *);
3199 struct perf_event *child;
3202 if (event->attr.type != attr->type)
3205 switch (event->attr.type) {
3206 case PERF_TYPE_BREAKPOINT:
3207 func = perf_event_modify_breakpoint;
3210 /* Place holder for future additions. */
3214 WARN_ON_ONCE(event->ctx->parent_ctx);
3216 mutex_lock(&event->child_mutex);
3217 err = func(event, attr);
3220 list_for_each_entry(child, &event->child_list, child_list) {
3221 err = func(child, attr);
3226 mutex_unlock(&event->child_mutex);
3230 static void ctx_sched_out(struct perf_event_context *ctx,
3231 struct perf_cpu_context *cpuctx,
3232 enum event_type_t event_type)
3234 struct perf_event *event, *tmp;
3235 int is_active = ctx->is_active;
3237 lockdep_assert_held(&ctx->lock);
3239 if (likely(!ctx->nr_events)) {
3241 * See __perf_remove_from_context().
3243 WARN_ON_ONCE(ctx->is_active);
3245 WARN_ON_ONCE(cpuctx->task_ctx);
3249 ctx->is_active &= ~event_type;
3250 if (!(ctx->is_active & EVENT_ALL))
3254 WARN_ON_ONCE(cpuctx->task_ctx != ctx);
3255 if (!ctx->is_active)
3256 cpuctx->task_ctx = NULL;
3260 * Always update time if it was set; not only when it changes.
3261 * Otherwise we can 'forget' to update time for any but the last
3262 * context we sched out. For example:
3264 * ctx_sched_out(.event_type = EVENT_FLEXIBLE)
3265 * ctx_sched_out(.event_type = EVENT_PINNED)
3267 * would only update time for the pinned events.
3269 if (is_active & EVENT_TIME) {
3270 /* update (and stop) ctx time */
3271 update_context_time(ctx);
3272 update_cgrp_time_from_cpuctx(cpuctx);
3275 is_active ^= ctx->is_active; /* changed bits */
3277 if (!ctx->nr_active || !(is_active & EVENT_ALL))
3280 perf_pmu_disable(ctx->pmu);
3281 if (is_active & EVENT_PINNED) {
3282 list_for_each_entry_safe(event, tmp, &ctx->pinned_active, active_list)
3283 group_sched_out(event, cpuctx, ctx);
3286 if (is_active & EVENT_FLEXIBLE) {
3287 list_for_each_entry_safe(event, tmp, &ctx->flexible_active, active_list)
3288 group_sched_out(event, cpuctx, ctx);
3291 * Since we cleared EVENT_FLEXIBLE, also clear
3292 * rotate_necessary, is will be reset by
3293 * ctx_flexible_sched_in() when needed.
3295 ctx->rotate_necessary = 0;
3297 perf_pmu_enable(ctx->pmu);
3301 * Test whether two contexts are equivalent, i.e. whether they have both been
3302 * cloned from the same version of the same context.
3304 * Equivalence is measured using a generation number in the context that is
3305 * incremented on each modification to it; see unclone_ctx(), list_add_event()
3306 * and list_del_event().
3308 static int context_equiv(struct perf_event_context *ctx1,
3309 struct perf_event_context *ctx2)
3311 lockdep_assert_held(&ctx1->lock);
3312 lockdep_assert_held(&ctx2->lock);
3314 /* Pinning disables the swap optimization */
3315 if (ctx1->pin_count || ctx2->pin_count)
3318 /* If ctx1 is the parent of ctx2 */
3319 if (ctx1 == ctx2->parent_ctx && ctx1->generation == ctx2->parent_gen)
3322 /* If ctx2 is the parent of ctx1 */
3323 if (ctx1->parent_ctx == ctx2 && ctx1->parent_gen == ctx2->generation)
3327 * If ctx1 and ctx2 have the same parent; we flatten the parent
3328 * hierarchy, see perf_event_init_context().
3330 if (ctx1->parent_ctx && ctx1->parent_ctx == ctx2->parent_ctx &&
3331 ctx1->parent_gen == ctx2->parent_gen)
3338 static void __perf_event_sync_stat(struct perf_event *event,
3339 struct perf_event *next_event)
3343 if (!event->attr.inherit_stat)
3347 * Update the event value, we cannot use perf_event_read()
3348 * because we're in the middle of a context switch and have IRQs
3349 * disabled, which upsets smp_call_function_single(), however
3350 * we know the event must be on the current CPU, therefore we
3351 * don't need to use it.
3353 if (event->state == PERF_EVENT_STATE_ACTIVE)
3354 event->pmu->read(event);
3356 perf_event_update_time(event);
3359 * In order to keep per-task stats reliable we need to flip the event
3360 * values when we flip the contexts.
3362 value = local64_read(&next_event->count);
3363 value = local64_xchg(&event->count, value);
3364 local64_set(&next_event->count, value);
3366 swap(event->total_time_enabled, next_event->total_time_enabled);
3367 swap(event->total_time_running, next_event->total_time_running);
3370 * Since we swizzled the values, update the user visible data too.
3372 perf_event_update_userpage(event);
3373 perf_event_update_userpage(next_event);
3376 static void perf_event_sync_stat(struct perf_event_context *ctx,
3377 struct perf_event_context *next_ctx)
3379 struct perf_event *event, *next_event;
3384 update_context_time(ctx);
3386 event = list_first_entry(&ctx->event_list,
3387 struct perf_event, event_entry);
3389 next_event = list_first_entry(&next_ctx->event_list,
3390 struct perf_event, event_entry);
3392 while (&event->event_entry != &ctx->event_list &&
3393 &next_event->event_entry != &next_ctx->event_list) {
3395 __perf_event_sync_stat(event, next_event);
3397 event = list_next_entry(event, event_entry);
3398 next_event = list_next_entry(next_event, event_entry);
3402 static void perf_event_context_sched_out(struct task_struct *task, int ctxn,
3403 struct task_struct *next)
3405 struct perf_event_context *ctx = task->perf_event_ctxp[ctxn];
3406 struct perf_event_context *next_ctx;
3407 struct perf_event_context *parent, *next_parent;
3408 struct perf_cpu_context *cpuctx;
3416 cpuctx = __get_cpu_context(ctx);
3417 if (!cpuctx->task_ctx)
3421 next_ctx = next->perf_event_ctxp[ctxn];
3425 parent = rcu_dereference(ctx->parent_ctx);
3426 next_parent = rcu_dereference(next_ctx->parent_ctx);
3428 /* If neither context have a parent context; they cannot be clones. */
3429 if (!parent && !next_parent)
3432 if (next_parent == ctx || next_ctx == parent || next_parent == parent) {
3434 * Looks like the two contexts are clones, so we might be
3435 * able to optimize the context switch. We lock both
3436 * contexts and check that they are clones under the
3437 * lock (including re-checking that neither has been
3438 * uncloned in the meantime). It doesn't matter which
3439 * order we take the locks because no other cpu could
3440 * be trying to lock both of these tasks.
3442 raw_spin_lock(&ctx->lock);
3443 raw_spin_lock_nested(&next_ctx->lock, SINGLE_DEPTH_NESTING);
3444 if (context_equiv(ctx, next_ctx)) {
3446 WRITE_ONCE(ctx->task, next);
3447 WRITE_ONCE(next_ctx->task, task);
3449 perf_pmu_disable(pmu);
3451 if (cpuctx->sched_cb_usage && pmu->sched_task)
3452 pmu->sched_task(ctx, false);
3455 * PMU specific parts of task perf context can require
3456 * additional synchronization. As an example of such
3457 * synchronization see implementation details of Intel
3458 * LBR call stack data profiling;
3460 if (pmu->swap_task_ctx)
3461 pmu->swap_task_ctx(ctx, next_ctx);
3463 swap(ctx->task_ctx_data, next_ctx->task_ctx_data);
3465 perf_pmu_enable(pmu);
3468 * RCU_INIT_POINTER here is safe because we've not
3469 * modified the ctx and the above modification of
3470 * ctx->task and ctx->task_ctx_data are immaterial
3471 * since those values are always verified under
3472 * ctx->lock which we're now holding.
3474 RCU_INIT_POINTER(task->perf_event_ctxp[ctxn], next_ctx);
3475 RCU_INIT_POINTER(next->perf_event_ctxp[ctxn], ctx);
3479 perf_event_sync_stat(ctx, next_ctx);
3481 raw_spin_unlock(&next_ctx->lock);
3482 raw_spin_unlock(&ctx->lock);
3488 raw_spin_lock(&ctx->lock);
3489 perf_pmu_disable(pmu);
3491 if (cpuctx->sched_cb_usage && pmu->sched_task)
3492 pmu->sched_task(ctx, false);
3493 task_ctx_sched_out(cpuctx, ctx, EVENT_ALL);
3495 perf_pmu_enable(pmu);
3496 raw_spin_unlock(&ctx->lock);
3500 static DEFINE_PER_CPU(struct list_head, sched_cb_list);
3502 void perf_sched_cb_dec(struct pmu *pmu)
3504 struct perf_cpu_context *cpuctx = this_cpu_ptr(pmu->pmu_cpu_context);
3506 this_cpu_dec(perf_sched_cb_usages);
3508 if (!--cpuctx->sched_cb_usage)
3509 list_del(&cpuctx->sched_cb_entry);
3513 void perf_sched_cb_inc(struct pmu *pmu)
3515 struct perf_cpu_context *cpuctx = this_cpu_ptr(pmu->pmu_cpu_context);
3517 if (!cpuctx->sched_cb_usage++)
3518 list_add(&cpuctx->sched_cb_entry, this_cpu_ptr(&sched_cb_list));
3520 this_cpu_inc(perf_sched_cb_usages);
3524 * This function provides the context switch callback to the lower code
3525 * layer. It is invoked ONLY when the context switch callback is enabled.
3527 * This callback is relevant even to per-cpu events; for example multi event
3528 * PEBS requires this to provide PID/TID information. This requires we flush
3529 * all queued PEBS records before we context switch to a new task.
3531 static void __perf_pmu_sched_task(struct perf_cpu_context *cpuctx, bool sched_in)
3535 pmu = cpuctx->ctx.pmu; /* software PMUs will not have sched_task */
3537 if (WARN_ON_ONCE(!pmu->sched_task))
3540 perf_ctx_lock(cpuctx, cpuctx->task_ctx);
3541 perf_pmu_disable(pmu);
3543 pmu->sched_task(cpuctx->task_ctx, sched_in);
3545 perf_pmu_enable(pmu);
3546 perf_ctx_unlock(cpuctx, cpuctx->task_ctx);
3549 static void perf_pmu_sched_task(struct task_struct *prev,
3550 struct task_struct *next,
3553 struct perf_cpu_context *cpuctx;
3558 list_for_each_entry(cpuctx, this_cpu_ptr(&sched_cb_list), sched_cb_entry) {
3559 /* will be handled in perf_event_context_sched_in/out */
3560 if (cpuctx->task_ctx)
3563 __perf_pmu_sched_task(cpuctx, sched_in);
3567 static void perf_event_switch(struct task_struct *task,
3568 struct task_struct *next_prev, bool sched_in);
3570 #define for_each_task_context_nr(ctxn) \
3571 for ((ctxn) = 0; (ctxn) < perf_nr_task_contexts; (ctxn)++)
3574 * Called from scheduler to remove the events of the current task,
3575 * with interrupts disabled.
3577 * We stop each event and update the event value in event->count.
3579 * This does not protect us against NMI, but disable()
3580 * sets the disabled bit in the control field of event _before_
3581 * accessing the event control register. If a NMI hits, then it will
3582 * not restart the event.
3584 void __perf_event_task_sched_out(struct task_struct *task,
3585 struct task_struct *next)
3589 if (__this_cpu_read(perf_sched_cb_usages))
3590 perf_pmu_sched_task(task, next, false);
3592 if (atomic_read(&nr_switch_events))
3593 perf_event_switch(task, next, false);
3595 for_each_task_context_nr(ctxn)
3596 perf_event_context_sched_out(task, ctxn, next);
3599 * if cgroup events exist on this CPU, then we need
3600 * to check if we have to switch out PMU state.
3601 * cgroup event are system-wide mode only
3603 if (atomic_read(this_cpu_ptr(&perf_cgroup_events)))
3604 perf_cgroup_sched_out(task, next);
3608 * Called with IRQs disabled
3610 static void cpu_ctx_sched_out(struct perf_cpu_context *cpuctx,
3611 enum event_type_t event_type)
3613 ctx_sched_out(&cpuctx->ctx, cpuctx, event_type);
3616 static bool perf_less_group_idx(const void *l, const void *r)
3618 const struct perf_event *le = *(const struct perf_event **)l;
3619 const struct perf_event *re = *(const struct perf_event **)r;
3621 return le->group_index < re->group_index;
3624 static void swap_ptr(void *l, void *r)
3626 void **lp = l, **rp = r;
3631 static const struct min_heap_callbacks perf_min_heap = {
3632 .elem_size = sizeof(struct perf_event *),
3633 .less = perf_less_group_idx,
3637 static void __heap_add(struct min_heap *heap, struct perf_event *event)
3639 struct perf_event **itrs = heap->data;
3642 itrs[heap->nr] = event;
3647 static noinline int visit_groups_merge(struct perf_cpu_context *cpuctx,
3648 struct perf_event_groups *groups, int cpu,
3649 int (*func)(struct perf_event *, void *),
3652 #ifdef CONFIG_CGROUP_PERF
3653 struct cgroup_subsys_state *css = NULL;
3655 /* Space for per CPU and/or any CPU event iterators. */
3656 struct perf_event *itrs[2];
3657 struct min_heap event_heap;
3658 struct perf_event **evt;
3662 event_heap = (struct min_heap){
3663 .data = cpuctx->heap,
3665 .size = cpuctx->heap_size,
3668 lockdep_assert_held(&cpuctx->ctx.lock);
3670 #ifdef CONFIG_CGROUP_PERF
3672 css = &cpuctx->cgrp->css;
3675 event_heap = (struct min_heap){
3678 .size = ARRAY_SIZE(itrs),
3680 /* Events not within a CPU context may be on any CPU. */
3681 __heap_add(&event_heap, perf_event_groups_first(groups, -1, NULL));
3683 evt = event_heap.data;
3685 __heap_add(&event_heap, perf_event_groups_first(groups, cpu, NULL));
3687 #ifdef CONFIG_CGROUP_PERF
3688 for (; css; css = css->parent)
3689 __heap_add(&event_heap, perf_event_groups_first(groups, cpu, css->cgroup));
3692 min_heapify_all(&event_heap, &perf_min_heap);
3694 while (event_heap.nr) {
3695 ret = func(*evt, data);
3699 *evt = perf_event_groups_next(*evt);
3701 min_heapify(&event_heap, 0, &perf_min_heap);
3703 min_heap_pop(&event_heap, &perf_min_heap);
3709 static int merge_sched_in(struct perf_event *event, void *data)
3711 struct perf_event_context *ctx = event->ctx;
3712 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
3713 int *can_add_hw = data;
3715 if (event->state <= PERF_EVENT_STATE_OFF)
3718 if (!event_filter_match(event))
3721 if (group_can_go_on(event, cpuctx, *can_add_hw)) {
3722 if (!group_sched_in(event, cpuctx, ctx))
3723 list_add_tail(&event->active_list, get_event_list(event));
3726 if (event->state == PERF_EVENT_STATE_INACTIVE) {
3727 if (event->attr.pinned) {
3728 perf_cgroup_event_disable(event, ctx);
3729 perf_event_set_state(event, PERF_EVENT_STATE_ERROR);
3733 ctx->rotate_necessary = 1;
3734 perf_mux_hrtimer_restart(cpuctx);
3741 ctx_pinned_sched_in(struct perf_event_context *ctx,
3742 struct perf_cpu_context *cpuctx)
3746 if (ctx != &cpuctx->ctx)
3749 visit_groups_merge(cpuctx, &ctx->pinned_groups,
3751 merge_sched_in, &can_add_hw);
3755 ctx_flexible_sched_in(struct perf_event_context *ctx,
3756 struct perf_cpu_context *cpuctx)
3760 if (ctx != &cpuctx->ctx)
3763 visit_groups_merge(cpuctx, &ctx->flexible_groups,
3765 merge_sched_in, &can_add_hw);
3769 ctx_sched_in(struct perf_event_context *ctx,
3770 struct perf_cpu_context *cpuctx,
3771 enum event_type_t event_type,
3772 struct task_struct *task)
3774 int is_active = ctx->is_active;
3777 lockdep_assert_held(&ctx->lock);
3779 if (likely(!ctx->nr_events))
3782 ctx->is_active |= (event_type | EVENT_TIME);
3785 cpuctx->task_ctx = ctx;
3787 WARN_ON_ONCE(cpuctx->task_ctx != ctx);
3790 is_active ^= ctx->is_active; /* changed bits */
3792 if (is_active & EVENT_TIME) {
3793 /* start ctx time */
3795 ctx->timestamp = now;
3796 perf_cgroup_set_timestamp(task, ctx);
3800 * First go through the list and put on any pinned groups
3801 * in order to give them the best chance of going on.
3803 if (is_active & EVENT_PINNED)
3804 ctx_pinned_sched_in(ctx, cpuctx);
3806 /* Then walk through the lower prio flexible groups */
3807 if (is_active & EVENT_FLEXIBLE)
3808 ctx_flexible_sched_in(ctx, cpuctx);
3811 static void cpu_ctx_sched_in(struct perf_cpu_context *cpuctx,
3812 enum event_type_t event_type,
3813 struct task_struct *task)
3815 struct perf_event_context *ctx = &cpuctx->ctx;
3817 ctx_sched_in(ctx, cpuctx, event_type, task);
3820 static void perf_event_context_sched_in(struct perf_event_context *ctx,
3821 struct task_struct *task)
3823 struct perf_cpu_context *cpuctx;
3826 cpuctx = __get_cpu_context(ctx);
3829 * HACK: for HETEROGENEOUS the task context might have switched to a
3830 * different PMU, force (re)set the context,
3832 pmu = ctx->pmu = cpuctx->ctx.pmu;
3834 if (cpuctx->task_ctx == ctx) {
3835 if (cpuctx->sched_cb_usage)
3836 __perf_pmu_sched_task(cpuctx, true);
3840 perf_ctx_lock(cpuctx, ctx);
3842 * We must check ctx->nr_events while holding ctx->lock, such
3843 * that we serialize against perf_install_in_context().
3845 if (!ctx->nr_events)
3848 perf_pmu_disable(pmu);
3850 * We want to keep the following priority order:
3851 * cpu pinned (that don't need to move), task pinned,
3852 * cpu flexible, task flexible.
3854 * However, if task's ctx is not carrying any pinned
3855 * events, no need to flip the cpuctx's events around.
3857 if (!RB_EMPTY_ROOT(&ctx->pinned_groups.tree))
3858 cpu_ctx_sched_out(cpuctx, EVENT_FLEXIBLE);
3859 perf_event_sched_in(cpuctx, ctx, task);
3861 if (cpuctx->sched_cb_usage && pmu->sched_task)
3862 pmu->sched_task(cpuctx->task_ctx, true);
3864 perf_pmu_enable(pmu);
3867 perf_ctx_unlock(cpuctx, ctx);
3871 * Called from scheduler to add the events of the current task
3872 * with interrupts disabled.
3874 * We restore the event value and then enable it.
3876 * This does not protect us against NMI, but enable()
3877 * sets the enabled bit in the control field of event _before_
3878 * accessing the event control register. If a NMI hits, then it will
3879 * keep the event running.
3881 void __perf_event_task_sched_in(struct task_struct *prev,
3882 struct task_struct *task)
3884 struct perf_event_context *ctx;
3888 * If cgroup events exist on this CPU, then we need to check if we have
3889 * to switch in PMU state; cgroup event are system-wide mode only.
3891 * Since cgroup events are CPU events, we must schedule these in before
3892 * we schedule in the task events.
3894 if (atomic_read(this_cpu_ptr(&perf_cgroup_events)))
3895 perf_cgroup_sched_in(prev, task);
3897 for_each_task_context_nr(ctxn) {
3898 ctx = task->perf_event_ctxp[ctxn];
3902 perf_event_context_sched_in(ctx, task);
3905 if (atomic_read(&nr_switch_events))
3906 perf_event_switch(task, prev, true);
3908 if (__this_cpu_read(perf_sched_cb_usages))
3909 perf_pmu_sched_task(prev, task, true);
3912 static u64 perf_calculate_period(struct perf_event *event, u64 nsec, u64 count)
3914 u64 frequency = event->attr.sample_freq;
3915 u64 sec = NSEC_PER_SEC;
3916 u64 divisor, dividend;
3918 int count_fls, nsec_fls, frequency_fls, sec_fls;
3920 count_fls = fls64(count);
3921 nsec_fls = fls64(nsec);
3922 frequency_fls = fls64(frequency);
3926 * We got @count in @nsec, with a target of sample_freq HZ
3927 * the target period becomes:
3930 * period = -------------------
3931 * @nsec * sample_freq
3936 * Reduce accuracy by one bit such that @a and @b converge
3937 * to a similar magnitude.
3939 #define REDUCE_FLS(a, b) \
3941 if (a##_fls > b##_fls) { \
3951 * Reduce accuracy until either term fits in a u64, then proceed with
3952 * the other, so that finally we can do a u64/u64 division.
3954 while (count_fls + sec_fls > 64 && nsec_fls + frequency_fls > 64) {
3955 REDUCE_FLS(nsec, frequency);
3956 REDUCE_FLS(sec, count);
3959 if (count_fls + sec_fls > 64) {
3960 divisor = nsec * frequency;
3962 while (count_fls + sec_fls > 64) {
3963 REDUCE_FLS(count, sec);
3967 dividend = count * sec;
3969 dividend = count * sec;
3971 while (nsec_fls + frequency_fls > 64) {
3972 REDUCE_FLS(nsec, frequency);
3976 divisor = nsec * frequency;
3982 return div64_u64(dividend, divisor);
3985 static DEFINE_PER_CPU(int, perf_throttled_count);
3986 static DEFINE_PER_CPU(u64, perf_throttled_seq);
3988 static void perf_adjust_period(struct perf_event *event, u64 nsec, u64 count, bool disable)
3990 struct hw_perf_event *hwc = &event->hw;
3991 s64 period, sample_period;
3994 period = perf_calculate_period(event, nsec, count);
3996 delta = (s64)(period - hwc->sample_period);
3997 delta = (delta + 7) / 8; /* low pass filter */
3999 sample_period = hwc->sample_period + delta;
4004 hwc->sample_period = sample_period;
4006 if (local64_read(&hwc->period_left) > 8*sample_period) {
4008 event->pmu->stop(event, PERF_EF_UPDATE);
4010 local64_set(&hwc->period_left, 0);
4013 event->pmu->start(event, PERF_EF_RELOAD);
4018 * combine freq adjustment with unthrottling to avoid two passes over the
4019 * events. At the same time, make sure, having freq events does not change
4020 * the rate of unthrottling as that would introduce bias.
4022 static void perf_adjust_freq_unthr_context(struct perf_event_context *ctx,
4025 struct perf_event *event;
4026 struct hw_perf_event *hwc;
4027 u64 now, period = TICK_NSEC;
4031 * only need to iterate over all events iff:
4032 * - context have events in frequency mode (needs freq adjust)
4033 * - there are events to unthrottle on this cpu
4035 if (!(ctx->nr_freq || needs_unthr))
4038 raw_spin_lock(&ctx->lock);
4039 perf_pmu_disable(ctx->pmu);
4041 list_for_each_entry_rcu(event, &ctx->event_list, event_entry) {
4042 if (event->state != PERF_EVENT_STATE_ACTIVE)
4045 if (!event_filter_match(event))
4048 perf_pmu_disable(event->pmu);
4052 if (hwc->interrupts == MAX_INTERRUPTS) {
4053 hwc->interrupts = 0;
4054 perf_log_throttle(event, 1);
4055 event->pmu->start(event, 0);
4058 if (!event->attr.freq || !event->attr.sample_freq)
4062 * stop the event and update event->count
4064 event->pmu->stop(event, PERF_EF_UPDATE);
4066 now = local64_read(&event->count);
4067 delta = now - hwc->freq_count_stamp;
4068 hwc->freq_count_stamp = now;
4072 * reload only if value has changed
4073 * we have stopped the event so tell that
4074 * to perf_adjust_period() to avoid stopping it
4078 perf_adjust_period(event, period, delta, false);
4080 event->pmu->start(event, delta > 0 ? PERF_EF_RELOAD : 0);
4082 perf_pmu_enable(event->pmu);
4085 perf_pmu_enable(ctx->pmu);
4086 raw_spin_unlock(&ctx->lock);
4090 * Move @event to the tail of the @ctx's elegible events.
4092 static void rotate_ctx(struct perf_event_context *ctx, struct perf_event *event)
4095 * Rotate the first entry last of non-pinned groups. Rotation might be
4096 * disabled by the inheritance code.
4098 if (ctx->rotate_disable)
4101 perf_event_groups_delete(&ctx->flexible_groups, event);
4102 perf_event_groups_insert(&ctx->flexible_groups, event);
4105 /* pick an event from the flexible_groups to rotate */
4106 static inline struct perf_event *
4107 ctx_event_to_rotate(struct perf_event_context *ctx)
4109 struct perf_event *event;
4111 /* pick the first active flexible event */
4112 event = list_first_entry_or_null(&ctx->flexible_active,
4113 struct perf_event, active_list);
4115 /* if no active flexible event, pick the first event */
4117 event = rb_entry_safe(rb_first(&ctx->flexible_groups.tree),
4118 typeof(*event), group_node);
4122 * Unconditionally clear rotate_necessary; if ctx_flexible_sched_in()
4123 * finds there are unschedulable events, it will set it again.
4125 ctx->rotate_necessary = 0;
4130 static bool perf_rotate_context(struct perf_cpu_context *cpuctx)
4132 struct perf_event *cpu_event = NULL, *task_event = NULL;
4133 struct perf_event_context *task_ctx = NULL;
4134 int cpu_rotate, task_rotate;
4137 * Since we run this from IRQ context, nobody can install new
4138 * events, thus the event count values are stable.
4141 cpu_rotate = cpuctx->ctx.rotate_necessary;
4142 task_ctx = cpuctx->task_ctx;
4143 task_rotate = task_ctx ? task_ctx->rotate_necessary : 0;
4145 if (!(cpu_rotate || task_rotate))
4148 perf_ctx_lock(cpuctx, cpuctx->task_ctx);
4149 perf_pmu_disable(cpuctx->ctx.pmu);
4152 task_event = ctx_event_to_rotate(task_ctx);
4154 cpu_event = ctx_event_to_rotate(&cpuctx->ctx);
4157 * As per the order given at ctx_resched() first 'pop' task flexible
4158 * and then, if needed CPU flexible.
4160 if (task_event || (task_ctx && cpu_event))
4161 ctx_sched_out(task_ctx, cpuctx, EVENT_FLEXIBLE);
4163 cpu_ctx_sched_out(cpuctx, EVENT_FLEXIBLE);
4166 rotate_ctx(task_ctx, task_event);
4168 rotate_ctx(&cpuctx->ctx, cpu_event);
4170 perf_event_sched_in(cpuctx, task_ctx, current);
4172 perf_pmu_enable(cpuctx->ctx.pmu);
4173 perf_ctx_unlock(cpuctx, cpuctx->task_ctx);
4178 void perf_event_task_tick(void)
4180 struct list_head *head = this_cpu_ptr(&active_ctx_list);
4181 struct perf_event_context *ctx, *tmp;
4184 lockdep_assert_irqs_disabled();
4186 __this_cpu_inc(perf_throttled_seq);
4187 throttled = __this_cpu_xchg(perf_throttled_count, 0);
4188 tick_dep_clear_cpu(smp_processor_id(), TICK_DEP_BIT_PERF_EVENTS);
4190 list_for_each_entry_safe(ctx, tmp, head, active_ctx_list)
4191 perf_adjust_freq_unthr_context(ctx, throttled);
4194 static int event_enable_on_exec(struct perf_event *event,
4195 struct perf_event_context *ctx)
4197 if (!event->attr.enable_on_exec)
4200 event->attr.enable_on_exec = 0;
4201 if (event->state >= PERF_EVENT_STATE_INACTIVE)
4204 perf_event_set_state(event, PERF_EVENT_STATE_INACTIVE);
4210 * Enable all of a task's events that have been marked enable-on-exec.
4211 * This expects task == current.
4213 static void perf_event_enable_on_exec(int ctxn)
4215 struct perf_event_context *ctx, *clone_ctx = NULL;
4216 enum event_type_t event_type = 0;
4217 struct perf_cpu_context *cpuctx;
4218 struct perf_event *event;
4219 unsigned long flags;
4222 local_irq_save(flags);
4223 ctx = current->perf_event_ctxp[ctxn];
4224 if (!ctx || !ctx->nr_events)
4227 cpuctx = __get_cpu_context(ctx);
4228 perf_ctx_lock(cpuctx, ctx);
4229 ctx_sched_out(ctx, cpuctx, EVENT_TIME);
4230 list_for_each_entry(event, &ctx->event_list, event_entry) {
4231 enabled |= event_enable_on_exec(event, ctx);
4232 event_type |= get_event_type(event);
4236 * Unclone and reschedule this context if we enabled any event.
4239 clone_ctx = unclone_ctx(ctx);
4240 ctx_resched(cpuctx, ctx, event_type);
4242 ctx_sched_in(ctx, cpuctx, EVENT_TIME, current);
4244 perf_ctx_unlock(cpuctx, ctx);
4247 local_irq_restore(flags);
4253 static void perf_remove_from_owner(struct perf_event *event);
4254 static void perf_event_exit_event(struct perf_event *event,
4255 struct perf_event_context *ctx);
4258 * Removes all events from the current task that have been marked
4259 * remove-on-exec, and feeds their values back to parent events.
4261 static void perf_event_remove_on_exec(int ctxn)
4263 struct perf_event_context *ctx, *clone_ctx = NULL;
4264 struct perf_event *event, *next;
4265 LIST_HEAD(free_list);
4266 unsigned long flags;
4267 bool modified = false;
4269 ctx = perf_pin_task_context(current, ctxn);
4273 mutex_lock(&ctx->mutex);
4275 if (WARN_ON_ONCE(ctx->task != current))
4278 list_for_each_entry_safe(event, next, &ctx->event_list, event_entry) {
4279 if (!event->attr.remove_on_exec)
4282 if (!is_kernel_event(event))
4283 perf_remove_from_owner(event);
4287 perf_event_exit_event(event, ctx);
4290 raw_spin_lock_irqsave(&ctx->lock, flags);
4292 clone_ctx = unclone_ctx(ctx);
4294 raw_spin_unlock_irqrestore(&ctx->lock, flags);
4297 mutex_unlock(&ctx->mutex);
4304 struct perf_read_data {
4305 struct perf_event *event;
4310 static int __perf_event_read_cpu(struct perf_event *event, int event_cpu)
4312 u16 local_pkg, event_pkg;
4314 if (event->group_caps & PERF_EV_CAP_READ_ACTIVE_PKG) {
4315 int local_cpu = smp_processor_id();
4317 event_pkg = topology_physical_package_id(event_cpu);
4318 local_pkg = topology_physical_package_id(local_cpu);
4320 if (event_pkg == local_pkg)
4328 * Cross CPU call to read the hardware event
4330 static void __perf_event_read(void *info)
4332 struct perf_read_data *data = info;
4333 struct perf_event *sub, *event = data->event;
4334 struct perf_event_context *ctx = event->ctx;
4335 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
4336 struct pmu *pmu = event->pmu;
4339 * If this is a task context, we need to check whether it is
4340 * the current task context of this cpu. If not it has been
4341 * scheduled out before the smp call arrived. In that case
4342 * event->count would have been updated to a recent sample
4343 * when the event was scheduled out.
4345 if (ctx->task && cpuctx->task_ctx != ctx)
4348 raw_spin_lock(&ctx->lock);
4349 if (ctx->is_active & EVENT_TIME) {
4350 update_context_time(ctx);
4351 update_cgrp_time_from_event(event);
4354 perf_event_update_time(event);
4356 perf_event_update_sibling_time(event);
4358 if (event->state != PERF_EVENT_STATE_ACTIVE)
4367 pmu->start_txn(pmu, PERF_PMU_TXN_READ);
4371 for_each_sibling_event(sub, event) {
4372 if (sub->state == PERF_EVENT_STATE_ACTIVE) {
4374 * Use sibling's PMU rather than @event's since
4375 * sibling could be on different (eg: software) PMU.
4377 sub->pmu->read(sub);
4381 data->ret = pmu->commit_txn(pmu);
4384 raw_spin_unlock(&ctx->lock);
4387 static inline u64 perf_event_count(struct perf_event *event)
4389 return local64_read(&event->count) + atomic64_read(&event->child_count);
4393 * NMI-safe method to read a local event, that is an event that
4395 * - either for the current task, or for this CPU
4396 * - does not have inherit set, for inherited task events
4397 * will not be local and we cannot read them atomically
4398 * - must not have a pmu::count method
4400 int perf_event_read_local(struct perf_event *event, u64 *value,
4401 u64 *enabled, u64 *running)
4403 unsigned long flags;
4407 * Disabling interrupts avoids all counter scheduling (context
4408 * switches, timer based rotation and IPIs).
4410 local_irq_save(flags);
4413 * It must not be an event with inherit set, we cannot read
4414 * all child counters from atomic context.
4416 if (event->attr.inherit) {
4421 /* If this is a per-task event, it must be for current */
4422 if ((event->attach_state & PERF_ATTACH_TASK) &&
4423 event->hw.target != current) {
4428 /* If this is a per-CPU event, it must be for this CPU */
4429 if (!(event->attach_state & PERF_ATTACH_TASK) &&
4430 event->cpu != smp_processor_id()) {
4435 /* If this is a pinned event it must be running on this CPU */
4436 if (event->attr.pinned && event->oncpu != smp_processor_id()) {
4442 * If the event is currently on this CPU, its either a per-task event,
4443 * or local to this CPU. Furthermore it means its ACTIVE (otherwise
4446 if (event->oncpu == smp_processor_id())
4447 event->pmu->read(event);
4449 *value = local64_read(&event->count);
4450 if (enabled || running) {
4451 u64 now = event->shadow_ctx_time + perf_clock();
4452 u64 __enabled, __running;
4454 __perf_update_times(event, now, &__enabled, &__running);
4456 *enabled = __enabled;
4458 *running = __running;
4461 local_irq_restore(flags);
4466 static int perf_event_read(struct perf_event *event, bool group)
4468 enum perf_event_state state = READ_ONCE(event->state);
4469 int event_cpu, ret = 0;
4472 * If event is enabled and currently active on a CPU, update the
4473 * value in the event structure:
4476 if (state == PERF_EVENT_STATE_ACTIVE) {
4477 struct perf_read_data data;
4480 * Orders the ->state and ->oncpu loads such that if we see
4481 * ACTIVE we must also see the right ->oncpu.
4483 * Matches the smp_wmb() from event_sched_in().
4487 event_cpu = READ_ONCE(event->oncpu);
4488 if ((unsigned)event_cpu >= nr_cpu_ids)
4491 data = (struct perf_read_data){
4498 event_cpu = __perf_event_read_cpu(event, event_cpu);
4501 * Purposely ignore the smp_call_function_single() return
4504 * If event_cpu isn't a valid CPU it means the event got
4505 * scheduled out and that will have updated the event count.
4507 * Therefore, either way, we'll have an up-to-date event count
4510 (void)smp_call_function_single(event_cpu, __perf_event_read, &data, 1);
4514 } else if (state == PERF_EVENT_STATE_INACTIVE) {
4515 struct perf_event_context *ctx = event->ctx;
4516 unsigned long flags;
4518 raw_spin_lock_irqsave(&ctx->lock, flags);
4519 state = event->state;
4520 if (state != PERF_EVENT_STATE_INACTIVE) {
4521 raw_spin_unlock_irqrestore(&ctx->lock, flags);
4526 * May read while context is not active (e.g., thread is
4527 * blocked), in that case we cannot update context time
4529 if (ctx->is_active & EVENT_TIME) {
4530 update_context_time(ctx);
4531 update_cgrp_time_from_event(event);
4534 perf_event_update_time(event);
4536 perf_event_update_sibling_time(event);
4537 raw_spin_unlock_irqrestore(&ctx->lock, flags);
4544 * Initialize the perf_event context in a task_struct:
4546 static void __perf_event_init_context(struct perf_event_context *ctx)
4548 raw_spin_lock_init(&ctx->lock);
4549 mutex_init(&ctx->mutex);
4550 INIT_LIST_HEAD(&ctx->active_ctx_list);
4551 perf_event_groups_init(&ctx->pinned_groups);
4552 perf_event_groups_init(&ctx->flexible_groups);
4553 INIT_LIST_HEAD(&ctx->event_list);
4554 INIT_LIST_HEAD(&ctx->pinned_active);
4555 INIT_LIST_HEAD(&ctx->flexible_active);
4556 refcount_set(&ctx->refcount, 1);
4559 static struct perf_event_context *
4560 alloc_perf_context(struct pmu *pmu, struct task_struct *task)
4562 struct perf_event_context *ctx;
4564 ctx = kzalloc(sizeof(struct perf_event_context), GFP_KERNEL);
4568 __perf_event_init_context(ctx);
4570 ctx->task = get_task_struct(task);
4576 static struct task_struct *
4577 find_lively_task_by_vpid(pid_t vpid)
4579 struct task_struct *task;
4585 task = find_task_by_vpid(vpid);
4587 get_task_struct(task);
4591 return ERR_PTR(-ESRCH);
4597 * Returns a matching context with refcount and pincount.
4599 static struct perf_event_context *
4600 find_get_context(struct pmu *pmu, struct task_struct *task,
4601 struct perf_event *event)
4603 struct perf_event_context *ctx, *clone_ctx = NULL;
4604 struct perf_cpu_context *cpuctx;
4605 void *task_ctx_data = NULL;
4606 unsigned long flags;
4608 int cpu = event->cpu;
4611 /* Must be root to operate on a CPU event: */
4612 err = perf_allow_cpu(&event->attr);
4614 return ERR_PTR(err);
4616 cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
4619 raw_spin_lock_irqsave(&ctx->lock, flags);
4621 raw_spin_unlock_irqrestore(&ctx->lock, flags);
4627 ctxn = pmu->task_ctx_nr;
4631 if (event->attach_state & PERF_ATTACH_TASK_DATA) {
4632 task_ctx_data = alloc_task_ctx_data(pmu);
4633 if (!task_ctx_data) {
4640 ctx = perf_lock_task_context(task, ctxn, &flags);
4642 clone_ctx = unclone_ctx(ctx);
4645 if (task_ctx_data && !ctx->task_ctx_data) {
4646 ctx->task_ctx_data = task_ctx_data;
4647 task_ctx_data = NULL;
4649 raw_spin_unlock_irqrestore(&ctx->lock, flags);
4654 ctx = alloc_perf_context(pmu, task);
4659 if (task_ctx_data) {
4660 ctx->task_ctx_data = task_ctx_data;
4661 task_ctx_data = NULL;
4665 mutex_lock(&task->perf_event_mutex);
4667 * If it has already passed perf_event_exit_task().
4668 * we must see PF_EXITING, it takes this mutex too.
4670 if (task->flags & PF_EXITING)
4672 else if (task->perf_event_ctxp[ctxn])
4677 rcu_assign_pointer(task->perf_event_ctxp[ctxn], ctx);
4679 mutex_unlock(&task->perf_event_mutex);
4681 if (unlikely(err)) {
4690 free_task_ctx_data(pmu, task_ctx_data);
4694 free_task_ctx_data(pmu, task_ctx_data);
4695 return ERR_PTR(err);
4698 static void perf_event_free_filter(struct perf_event *event);
4699 static void perf_event_free_bpf_prog(struct perf_event *event);
4701 static void free_event_rcu(struct rcu_head *head)
4703 struct perf_event *event;
4705 event = container_of(head, struct perf_event, rcu_head);
4707 put_pid_ns(event->ns);
4708 perf_event_free_filter(event);
4709 kmem_cache_free(perf_event_cache, event);
4712 static void ring_buffer_attach(struct perf_event *event,
4713 struct perf_buffer *rb);
4715 static void detach_sb_event(struct perf_event *event)
4717 struct pmu_event_list *pel = per_cpu_ptr(&pmu_sb_events, event->cpu);
4719 raw_spin_lock(&pel->lock);
4720 list_del_rcu(&event->sb_list);
4721 raw_spin_unlock(&pel->lock);
4724 static bool is_sb_event(struct perf_event *event)
4726 struct perf_event_attr *attr = &event->attr;
4731 if (event->attach_state & PERF_ATTACH_TASK)
4734 if (attr->mmap || attr->mmap_data || attr->mmap2 ||
4735 attr->comm || attr->comm_exec ||
4736 attr->task || attr->ksymbol ||
4737 attr->context_switch || attr->text_poke ||
4743 static void unaccount_pmu_sb_event(struct perf_event *event)
4745 if (is_sb_event(event))
4746 detach_sb_event(event);
4749 static void unaccount_event_cpu(struct perf_event *event, int cpu)
4754 if (is_cgroup_event(event))
4755 atomic_dec(&per_cpu(perf_cgroup_events, cpu));
4758 #ifdef CONFIG_NO_HZ_FULL
4759 static DEFINE_SPINLOCK(nr_freq_lock);
4762 static void unaccount_freq_event_nohz(void)
4764 #ifdef CONFIG_NO_HZ_FULL
4765 spin_lock(&nr_freq_lock);
4766 if (atomic_dec_and_test(&nr_freq_events))
4767 tick_nohz_dep_clear(TICK_DEP_BIT_PERF_EVENTS);
4768 spin_unlock(&nr_freq_lock);
4772 static void unaccount_freq_event(void)
4774 if (tick_nohz_full_enabled())
4775 unaccount_freq_event_nohz();
4777 atomic_dec(&nr_freq_events);
4780 static void unaccount_event(struct perf_event *event)
4787 if (event->attach_state & (PERF_ATTACH_TASK | PERF_ATTACH_SCHED_CB))
4789 if (event->attr.mmap || event->attr.mmap_data)
4790 atomic_dec(&nr_mmap_events);
4791 if (event->attr.build_id)
4792 atomic_dec(&nr_build_id_events);
4793 if (event->attr.comm)
4794 atomic_dec(&nr_comm_events);
4795 if (event->attr.namespaces)
4796 atomic_dec(&nr_namespaces_events);
4797 if (event->attr.cgroup)
4798 atomic_dec(&nr_cgroup_events);
4799 if (event->attr.task)
4800 atomic_dec(&nr_task_events);
4801 if (event->attr.freq)
4802 unaccount_freq_event();
4803 if (event->attr.context_switch) {
4805 atomic_dec(&nr_switch_events);
4807 if (is_cgroup_event(event))
4809 if (has_branch_stack(event))
4811 if (event->attr.ksymbol)
4812 atomic_dec(&nr_ksymbol_events);
4813 if (event->attr.bpf_event)
4814 atomic_dec(&nr_bpf_events);
4815 if (event->attr.text_poke)
4816 atomic_dec(&nr_text_poke_events);
4819 if (!atomic_add_unless(&perf_sched_count, -1, 1))
4820 schedule_delayed_work(&perf_sched_work, HZ);
4823 unaccount_event_cpu(event, event->cpu);
4825 unaccount_pmu_sb_event(event);
4828 static void perf_sched_delayed(struct work_struct *work)
4830 mutex_lock(&perf_sched_mutex);
4831 if (atomic_dec_and_test(&perf_sched_count))
4832 static_branch_disable(&perf_sched_events);
4833 mutex_unlock(&perf_sched_mutex);
4837 * The following implement mutual exclusion of events on "exclusive" pmus
4838 * (PERF_PMU_CAP_EXCLUSIVE). Such pmus can only have one event scheduled
4839 * at a time, so we disallow creating events that might conflict, namely:
4841 * 1) cpu-wide events in the presence of per-task events,
4842 * 2) per-task events in the presence of cpu-wide events,
4843 * 3) two matching events on the same context.
4845 * The former two cases are handled in the allocation path (perf_event_alloc(),
4846 * _free_event()), the latter -- before the first perf_install_in_context().
4848 static int exclusive_event_init(struct perf_event *event)
4850 struct pmu *pmu = event->pmu;
4852 if (!is_exclusive_pmu(pmu))
4856 * Prevent co-existence of per-task and cpu-wide events on the
4857 * same exclusive pmu.
4859 * Negative pmu::exclusive_cnt means there are cpu-wide
4860 * events on this "exclusive" pmu, positive means there are
4863 * Since this is called in perf_event_alloc() path, event::ctx
4864 * doesn't exist yet; it is, however, safe to use PERF_ATTACH_TASK
4865 * to mean "per-task event", because unlike other attach states it
4866 * never gets cleared.
4868 if (event->attach_state & PERF_ATTACH_TASK) {
4869 if (!atomic_inc_unless_negative(&pmu->exclusive_cnt))
4872 if (!atomic_dec_unless_positive(&pmu->exclusive_cnt))
4879 static void exclusive_event_destroy(struct perf_event *event)
4881 struct pmu *pmu = event->pmu;
4883 if (!is_exclusive_pmu(pmu))
4886 /* see comment in exclusive_event_init() */
4887 if (event->attach_state & PERF_ATTACH_TASK)
4888 atomic_dec(&pmu->exclusive_cnt);
4890 atomic_inc(&pmu->exclusive_cnt);
4893 static bool exclusive_event_match(struct perf_event *e1, struct perf_event *e2)
4895 if ((e1->pmu == e2->pmu) &&
4896 (e1->cpu == e2->cpu ||
4903 static bool exclusive_event_installable(struct perf_event *event,
4904 struct perf_event_context *ctx)
4906 struct perf_event *iter_event;
4907 struct pmu *pmu = event->pmu;
4909 lockdep_assert_held(&ctx->mutex);
4911 if (!is_exclusive_pmu(pmu))
4914 list_for_each_entry(iter_event, &ctx->event_list, event_entry) {
4915 if (exclusive_event_match(iter_event, event))
4922 static void perf_addr_filters_splice(struct perf_event *event,
4923 struct list_head *head);
4925 static void _free_event(struct perf_event *event)
4927 irq_work_sync(&event->pending);
4929 unaccount_event(event);
4931 security_perf_event_free(event);
4935 * Can happen when we close an event with re-directed output.
4937 * Since we have a 0 refcount, perf_mmap_close() will skip
4938 * over us; possibly making our ring_buffer_put() the last.
4940 mutex_lock(&event->mmap_mutex);
4941 ring_buffer_attach(event, NULL);
4942 mutex_unlock(&event->mmap_mutex);
4945 if (is_cgroup_event(event))
4946 perf_detach_cgroup(event);
4948 if (!event->parent) {
4949 if (event->attr.sample_type & PERF_SAMPLE_CALLCHAIN)
4950 put_callchain_buffers();
4953 perf_event_free_bpf_prog(event);
4954 perf_addr_filters_splice(event, NULL);
4955 kfree(event->addr_filter_ranges);
4958 event->destroy(event);
4961 * Must be after ->destroy(), due to uprobe_perf_close() using
4964 if (event->hw.target)
4965 put_task_struct(event->hw.target);
4968 * perf_event_free_task() relies on put_ctx() being 'last', in particular
4969 * all task references must be cleaned up.
4972 put_ctx(event->ctx);
4974 exclusive_event_destroy(event);
4975 module_put(event->pmu->module);
4977 call_rcu(&event->rcu_head, free_event_rcu);
4981 * Used to free events which have a known refcount of 1, such as in error paths
4982 * where the event isn't exposed yet and inherited events.
4984 static void free_event(struct perf_event *event)
4986 if (WARN(atomic_long_cmpxchg(&event->refcount, 1, 0) != 1,
4987 "unexpected event refcount: %ld; ptr=%p\n",
4988 atomic_long_read(&event->refcount), event)) {
4989 /* leak to avoid use-after-free */
4997 * Remove user event from the owner task.
4999 static void perf_remove_from_owner(struct perf_event *event)
5001 struct task_struct *owner;
5005 * Matches the smp_store_release() in perf_event_exit_task(). If we
5006 * observe !owner it means the list deletion is complete and we can
5007 * indeed free this event, otherwise we need to serialize on
5008 * owner->perf_event_mutex.
5010 owner = READ_ONCE(event->owner);
5013 * Since delayed_put_task_struct() also drops the last
5014 * task reference we can safely take a new reference
5015 * while holding the rcu_read_lock().
5017 get_task_struct(owner);
5023 * If we're here through perf_event_exit_task() we're already
5024 * holding ctx->mutex which would be an inversion wrt. the
5025 * normal lock order.
5027 * However we can safely take this lock because its the child
5030 mutex_lock_nested(&owner->perf_event_mutex, SINGLE_DEPTH_NESTING);
5033 * We have to re-check the event->owner field, if it is cleared
5034 * we raced with perf_event_exit_task(), acquiring the mutex
5035 * ensured they're done, and we can proceed with freeing the
5039 list_del_init(&event->owner_entry);
5040 smp_store_release(&event->owner, NULL);
5042 mutex_unlock(&owner->perf_event_mutex);
5043 put_task_struct(owner);
5047 static void put_event(struct perf_event *event)
5049 if (!atomic_long_dec_and_test(&event->refcount))
5056 * Kill an event dead; while event:refcount will preserve the event
5057 * object, it will not preserve its functionality. Once the last 'user'
5058 * gives up the object, we'll destroy the thing.
5060 int perf_event_release_kernel(struct perf_event *event)
5062 struct perf_event_context *ctx = event->ctx;
5063 struct perf_event *child, *tmp;
5064 LIST_HEAD(free_list);
5067 * If we got here through err_file: fput(event_file); we will not have
5068 * attached to a context yet.
5071 WARN_ON_ONCE(event->attach_state &
5072 (PERF_ATTACH_CONTEXT|PERF_ATTACH_GROUP));
5076 if (!is_kernel_event(event))
5077 perf_remove_from_owner(event);
5079 ctx = perf_event_ctx_lock(event);
5080 WARN_ON_ONCE(ctx->parent_ctx);
5081 perf_remove_from_context(event, DETACH_GROUP);
5083 raw_spin_lock_irq(&ctx->lock);
5085 * Mark this event as STATE_DEAD, there is no external reference to it
5088 * Anybody acquiring event->child_mutex after the below loop _must_
5089 * also see this, most importantly inherit_event() which will avoid
5090 * placing more children on the list.
5092 * Thus this guarantees that we will in fact observe and kill _ALL_
5095 event->state = PERF_EVENT_STATE_DEAD;
5096 raw_spin_unlock_irq(&ctx->lock);
5098 perf_event_ctx_unlock(event, ctx);
5101 mutex_lock(&event->child_mutex);
5102 list_for_each_entry(child, &event->child_list, child_list) {
5105 * Cannot change, child events are not migrated, see the
5106 * comment with perf_event_ctx_lock_nested().
5108 ctx = READ_ONCE(child->ctx);
5110 * Since child_mutex nests inside ctx::mutex, we must jump
5111 * through hoops. We start by grabbing a reference on the ctx.
5113 * Since the event cannot get freed while we hold the
5114 * child_mutex, the context must also exist and have a !0
5120 * Now that we have a ctx ref, we can drop child_mutex, and
5121 * acquire ctx::mutex without fear of it going away. Then we
5122 * can re-acquire child_mutex.
5124 mutex_unlock(&event->child_mutex);
5125 mutex_lock(&ctx->mutex);
5126 mutex_lock(&event->child_mutex);
5129 * Now that we hold ctx::mutex and child_mutex, revalidate our
5130 * state, if child is still the first entry, it didn't get freed
5131 * and we can continue doing so.
5133 tmp = list_first_entry_or_null(&event->child_list,
5134 struct perf_event, child_list);
5136 perf_remove_from_context(child, DETACH_GROUP);
5137 list_move(&child->child_list, &free_list);
5139 * This matches the refcount bump in inherit_event();
5140 * this can't be the last reference.
5145 mutex_unlock(&event->child_mutex);
5146 mutex_unlock(&ctx->mutex);
5150 mutex_unlock(&event->child_mutex);
5152 list_for_each_entry_safe(child, tmp, &free_list, child_list) {
5153 void *var = &child->ctx->refcount;
5155 list_del(&child->child_list);
5159 * Wake any perf_event_free_task() waiting for this event to be
5162 smp_mb(); /* pairs with wait_var_event() */
5167 put_event(event); /* Must be the 'last' reference */
5170 EXPORT_SYMBOL_GPL(perf_event_release_kernel);
5173 * Called when the last reference to the file is gone.
5175 static int perf_release(struct inode *inode, struct file *file)
5177 perf_event_release_kernel(file->private_data);
5181 static u64 __perf_event_read_value(struct perf_event *event, u64 *enabled, u64 *running)
5183 struct perf_event *child;
5189 mutex_lock(&event->child_mutex);
5191 (void)perf_event_read(event, false);
5192 total += perf_event_count(event);
5194 *enabled += event->total_time_enabled +
5195 atomic64_read(&event->child_total_time_enabled);
5196 *running += event->total_time_running +
5197 atomic64_read(&event->child_total_time_running);
5199 list_for_each_entry(child, &event->child_list, child_list) {
5200 (void)perf_event_read(child, false);
5201 total += perf_event_count(child);
5202 *enabled += child->total_time_enabled;
5203 *running += child->total_time_running;
5205 mutex_unlock(&event->child_mutex);
5210 u64 perf_event_read_value(struct perf_event *event, u64 *enabled, u64 *running)
5212 struct perf_event_context *ctx;
5215 ctx = perf_event_ctx_lock(event);
5216 count = __perf_event_read_value(event, enabled, running);
5217 perf_event_ctx_unlock(event, ctx);
5221 EXPORT_SYMBOL_GPL(perf_event_read_value);
5223 static int __perf_read_group_add(struct perf_event *leader,
5224 u64 read_format, u64 *values)
5226 struct perf_event_context *ctx = leader->ctx;
5227 struct perf_event *sub;
5228 unsigned long flags;
5229 int n = 1; /* skip @nr */
5232 ret = perf_event_read(leader, true);
5236 raw_spin_lock_irqsave(&ctx->lock, flags);
5239 * Since we co-schedule groups, {enabled,running} times of siblings
5240 * will be identical to those of the leader, so we only publish one
5243 if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED) {
5244 values[n++] += leader->total_time_enabled +
5245 atomic64_read(&leader->child_total_time_enabled);
5248 if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING) {
5249 values[n++] += leader->total_time_running +
5250 atomic64_read(&leader->child_total_time_running);
5254 * Write {count,id} tuples for every sibling.
5256 values[n++] += perf_event_count(leader);
5257 if (read_format & PERF_FORMAT_ID)
5258 values[n++] = primary_event_id(leader);
5260 for_each_sibling_event(sub, leader) {
5261 values[n++] += perf_event_count(sub);
5262 if (read_format & PERF_FORMAT_ID)
5263 values[n++] = primary_event_id(sub);
5266 raw_spin_unlock_irqrestore(&ctx->lock, flags);
5270 static int perf_read_group(struct perf_event *event,
5271 u64 read_format, char __user *buf)
5273 struct perf_event *leader = event->group_leader, *child;
5274 struct perf_event_context *ctx = leader->ctx;
5278 lockdep_assert_held(&ctx->mutex);
5280 values = kzalloc(event->read_size, GFP_KERNEL);
5284 values[0] = 1 + leader->nr_siblings;
5287 * By locking the child_mutex of the leader we effectively
5288 * lock the child list of all siblings.. XXX explain how.
5290 mutex_lock(&leader->child_mutex);
5292 ret = __perf_read_group_add(leader, read_format, values);
5296 list_for_each_entry(child, &leader->child_list, child_list) {
5297 ret = __perf_read_group_add(child, read_format, values);
5302 mutex_unlock(&leader->child_mutex);
5304 ret = event->read_size;
5305 if (copy_to_user(buf, values, event->read_size))
5310 mutex_unlock(&leader->child_mutex);
5316 static int perf_read_one(struct perf_event *event,
5317 u64 read_format, char __user *buf)
5319 u64 enabled, running;
5323 values[n++] = __perf_event_read_value(event, &enabled, &running);
5324 if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED)
5325 values[n++] = enabled;
5326 if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING)
5327 values[n++] = running;
5328 if (read_format & PERF_FORMAT_ID)
5329 values[n++] = primary_event_id(event);
5331 if (copy_to_user(buf, values, n * sizeof(u64)))
5334 return n * sizeof(u64);
5337 static bool is_event_hup(struct perf_event *event)
5341 if (event->state > PERF_EVENT_STATE_EXIT)
5344 mutex_lock(&event->child_mutex);
5345 no_children = list_empty(&event->child_list);
5346 mutex_unlock(&event->child_mutex);
5351 * Read the performance event - simple non blocking version for now
5354 __perf_read(struct perf_event *event, char __user *buf, size_t count)
5356 u64 read_format = event->attr.read_format;
5360 * Return end-of-file for a read on an event that is in
5361 * error state (i.e. because it was pinned but it couldn't be
5362 * scheduled on to the CPU at some point).
5364 if (event->state == PERF_EVENT_STATE_ERROR)
5367 if (count < event->read_size)
5370 WARN_ON_ONCE(event->ctx->parent_ctx);
5371 if (read_format & PERF_FORMAT_GROUP)
5372 ret = perf_read_group(event, read_format, buf);
5374 ret = perf_read_one(event, read_format, buf);
5380 perf_read(struct file *file, char __user *buf, size_t count, loff_t *ppos)
5382 struct perf_event *event = file->private_data;
5383 struct perf_event_context *ctx;
5386 ret = security_perf_event_read(event);
5390 ctx = perf_event_ctx_lock(event);
5391 ret = __perf_read(event, buf, count);
5392 perf_event_ctx_unlock(event, ctx);
5397 static __poll_t perf_poll(struct file *file, poll_table *wait)
5399 struct perf_event *event = file->private_data;
5400 struct perf_buffer *rb;
5401 __poll_t events = EPOLLHUP;
5403 poll_wait(file, &event->waitq, wait);
5405 if (is_event_hup(event))
5409 * Pin the event->rb by taking event->mmap_mutex; otherwise
5410 * perf_event_set_output() can swizzle our rb and make us miss wakeups.
5412 mutex_lock(&event->mmap_mutex);
5415 events = atomic_xchg(&rb->poll, 0);
5416 mutex_unlock(&event->mmap_mutex);
5420 static void _perf_event_reset(struct perf_event *event)
5422 (void)perf_event_read(event, false);
5423 local64_set(&event->count, 0);
5424 perf_event_update_userpage(event);
5427 /* Assume it's not an event with inherit set. */
5428 u64 perf_event_pause(struct perf_event *event, bool reset)
5430 struct perf_event_context *ctx;
5433 ctx = perf_event_ctx_lock(event);
5434 WARN_ON_ONCE(event->attr.inherit);
5435 _perf_event_disable(event);
5436 count = local64_read(&event->count);
5438 local64_set(&event->count, 0);
5439 perf_event_ctx_unlock(event, ctx);
5443 EXPORT_SYMBOL_GPL(perf_event_pause);
5446 * Holding the top-level event's child_mutex means that any
5447 * descendant process that has inherited this event will block
5448 * in perf_event_exit_event() if it goes to exit, thus satisfying the
5449 * task existence requirements of perf_event_enable/disable.
5451 static void perf_event_for_each_child(struct perf_event *event,
5452 void (*func)(struct perf_event *))
5454 struct perf_event *child;
5456 WARN_ON_ONCE(event->ctx->parent_ctx);
5458 mutex_lock(&event->child_mutex);
5460 list_for_each_entry(child, &event->child_list, child_list)
5462 mutex_unlock(&event->child_mutex);
5465 static void perf_event_for_each(struct perf_event *event,
5466 void (*func)(struct perf_event *))
5468 struct perf_event_context *ctx = event->ctx;
5469 struct perf_event *sibling;
5471 lockdep_assert_held(&ctx->mutex);
5473 event = event->group_leader;
5475 perf_event_for_each_child(event, func);
5476 for_each_sibling_event(sibling, event)
5477 perf_event_for_each_child(sibling, func);
5480 static void __perf_event_period(struct perf_event *event,
5481 struct perf_cpu_context *cpuctx,
5482 struct perf_event_context *ctx,
5485 u64 value = *((u64 *)info);
5488 if (event->attr.freq) {
5489 event->attr.sample_freq = value;
5491 event->attr.sample_period = value;
5492 event->hw.sample_period = value;
5495 active = (event->state == PERF_EVENT_STATE_ACTIVE);
5497 perf_pmu_disable(ctx->pmu);
5499 * We could be throttled; unthrottle now to avoid the tick
5500 * trying to unthrottle while we already re-started the event.
5502 if (event->hw.interrupts == MAX_INTERRUPTS) {
5503 event->hw.interrupts = 0;
5504 perf_log_throttle(event, 1);
5506 event->pmu->stop(event, PERF_EF_UPDATE);
5509 local64_set(&event->hw.period_left, 0);
5512 event->pmu->start(event, PERF_EF_RELOAD);
5513 perf_pmu_enable(ctx->pmu);
5517 static int perf_event_check_period(struct perf_event *event, u64 value)
5519 return event->pmu->check_period(event, value);
5522 static int _perf_event_period(struct perf_event *event, u64 value)
5524 if (!is_sampling_event(event))
5530 if (event->attr.freq && value > sysctl_perf_event_sample_rate)
5533 if (perf_event_check_period(event, value))
5536 if (!event->attr.freq && (value & (1ULL << 63)))
5539 event_function_call(event, __perf_event_period, &value);
5544 int perf_event_period(struct perf_event *event, u64 value)
5546 struct perf_event_context *ctx;
5549 ctx = perf_event_ctx_lock(event);
5550 ret = _perf_event_period(event, value);
5551 perf_event_ctx_unlock(event, ctx);
5555 EXPORT_SYMBOL_GPL(perf_event_period);
5557 static const struct file_operations perf_fops;
5559 static inline int perf_fget_light(int fd, struct fd *p)
5561 struct fd f = fdget(fd);
5565 if (f.file->f_op != &perf_fops) {
5573 static int perf_event_set_output(struct perf_event *event,
5574 struct perf_event *output_event);
5575 static int perf_event_set_filter(struct perf_event *event, void __user *arg);
5576 static int perf_event_set_bpf_prog(struct perf_event *event, u32 prog_fd);
5577 static int perf_copy_attr(struct perf_event_attr __user *uattr,
5578 struct perf_event_attr *attr);
5580 static long _perf_ioctl(struct perf_event *event, unsigned int cmd, unsigned long arg)
5582 void (*func)(struct perf_event *);
5586 case PERF_EVENT_IOC_ENABLE:
5587 func = _perf_event_enable;
5589 case PERF_EVENT_IOC_DISABLE:
5590 func = _perf_event_disable;
5592 case PERF_EVENT_IOC_RESET:
5593 func = _perf_event_reset;
5596 case PERF_EVENT_IOC_REFRESH:
5597 return _perf_event_refresh(event, arg);
5599 case PERF_EVENT_IOC_PERIOD:
5603 if (copy_from_user(&value, (u64 __user *)arg, sizeof(value)))
5606 return _perf_event_period(event, value);
5608 case PERF_EVENT_IOC_ID:
5610 u64 id = primary_event_id(event);
5612 if (copy_to_user((void __user *)arg, &id, sizeof(id)))
5617 case PERF_EVENT_IOC_SET_OUTPUT:
5621 struct perf_event *output_event;
5623 ret = perf_fget_light(arg, &output);
5626 output_event = output.file->private_data;
5627 ret = perf_event_set_output(event, output_event);
5630 ret = perf_event_set_output(event, NULL);
5635 case PERF_EVENT_IOC_SET_FILTER:
5636 return perf_event_set_filter(event, (void __user *)arg);
5638 case PERF_EVENT_IOC_SET_BPF:
5639 return perf_event_set_bpf_prog(event, arg);
5641 case PERF_EVENT_IOC_PAUSE_OUTPUT: {
5642 struct perf_buffer *rb;
5645 rb = rcu_dereference(event->rb);
5646 if (!rb || !rb->nr_pages) {
5650 rb_toggle_paused(rb, !!arg);
5655 case PERF_EVENT_IOC_QUERY_BPF:
5656 return perf_event_query_prog_array(event, (void __user *)arg);
5658 case PERF_EVENT_IOC_MODIFY_ATTRIBUTES: {
5659 struct perf_event_attr new_attr;
5660 int err = perf_copy_attr((struct perf_event_attr __user *)arg,
5666 return perf_event_modify_attr(event, &new_attr);
5672 if (flags & PERF_IOC_FLAG_GROUP)
5673 perf_event_for_each(event, func);
5675 perf_event_for_each_child(event, func);
5680 static long perf_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
5682 struct perf_event *event = file->private_data;
5683 struct perf_event_context *ctx;
5686 /* Treat ioctl like writes as it is likely a mutating operation. */
5687 ret = security_perf_event_write(event);
5691 ctx = perf_event_ctx_lock(event);
5692 ret = _perf_ioctl(event, cmd, arg);
5693 perf_event_ctx_unlock(event, ctx);
5698 #ifdef CONFIG_COMPAT
5699 static long perf_compat_ioctl(struct file *file, unsigned int cmd,
5702 switch (_IOC_NR(cmd)) {
5703 case _IOC_NR(PERF_EVENT_IOC_SET_FILTER):
5704 case _IOC_NR(PERF_EVENT_IOC_ID):
5705 case _IOC_NR(PERF_EVENT_IOC_QUERY_BPF):
5706 case _IOC_NR(PERF_EVENT_IOC_MODIFY_ATTRIBUTES):
5707 /* Fix up pointer size (usually 4 -> 8 in 32-on-64-bit case */
5708 if (_IOC_SIZE(cmd) == sizeof(compat_uptr_t)) {
5709 cmd &= ~IOCSIZE_MASK;
5710 cmd |= sizeof(void *) << IOCSIZE_SHIFT;
5714 return perf_ioctl(file, cmd, arg);
5717 # define perf_compat_ioctl NULL
5720 int perf_event_task_enable(void)
5722 struct perf_event_context *ctx;
5723 struct perf_event *event;
5725 mutex_lock(¤t->perf_event_mutex);
5726 list_for_each_entry(event, ¤t->perf_event_list, owner_entry) {
5727 ctx = perf_event_ctx_lock(event);
5728 perf_event_for_each_child(event, _perf_event_enable);
5729 perf_event_ctx_unlock(event, ctx);
5731 mutex_unlock(¤t->perf_event_mutex);
5736 int perf_event_task_disable(void)
5738 struct perf_event_context *ctx;
5739 struct perf_event *event;
5741 mutex_lock(¤t->perf_event_mutex);
5742 list_for_each_entry(event, ¤t->perf_event_list, owner_entry) {
5743 ctx = perf_event_ctx_lock(event);
5744 perf_event_for_each_child(event, _perf_event_disable);
5745 perf_event_ctx_unlock(event, ctx);
5747 mutex_unlock(¤t->perf_event_mutex);
5752 static int perf_event_index(struct perf_event *event)
5754 if (event->hw.state & PERF_HES_STOPPED)
5757 if (event->state != PERF_EVENT_STATE_ACTIVE)
5760 return event->pmu->event_idx(event);
5763 static void calc_timer_values(struct perf_event *event,
5770 *now = perf_clock();
5771 ctx_time = event->shadow_ctx_time + *now;
5772 __perf_update_times(event, ctx_time, enabled, running);
5775 static void perf_event_init_userpage(struct perf_event *event)
5777 struct perf_event_mmap_page *userpg;
5778 struct perf_buffer *rb;
5781 rb = rcu_dereference(event->rb);
5785 userpg = rb->user_page;
5787 /* Allow new userspace to detect that bit 0 is deprecated */
5788 userpg->cap_bit0_is_deprecated = 1;
5789 userpg->size = offsetof(struct perf_event_mmap_page, __reserved);
5790 userpg->data_offset = PAGE_SIZE;
5791 userpg->data_size = perf_data_size(rb);
5797 void __weak arch_perf_update_userpage(
5798 struct perf_event *event, struct perf_event_mmap_page *userpg, u64 now)
5803 * Callers need to ensure there can be no nesting of this function, otherwise
5804 * the seqlock logic goes bad. We can not serialize this because the arch
5805 * code calls this from NMI context.
5807 void perf_event_update_userpage(struct perf_event *event)
5809 struct perf_event_mmap_page *userpg;
5810 struct perf_buffer *rb;
5811 u64 enabled, running, now;
5814 rb = rcu_dereference(event->rb);
5819 * compute total_time_enabled, total_time_running
5820 * based on snapshot values taken when the event
5821 * was last scheduled in.
5823 * we cannot simply called update_context_time()
5824 * because of locking issue as we can be called in
5827 calc_timer_values(event, &now, &enabled, &running);
5829 userpg = rb->user_page;
5831 * Disable preemption to guarantee consistent time stamps are stored to
5837 userpg->index = perf_event_index(event);
5838 userpg->offset = perf_event_count(event);
5840 userpg->offset -= local64_read(&event->hw.prev_count);
5842 userpg->time_enabled = enabled +
5843 atomic64_read(&event->child_total_time_enabled);
5845 userpg->time_running = running +
5846 atomic64_read(&event->child_total_time_running);
5848 arch_perf_update_userpage(event, userpg, now);
5856 EXPORT_SYMBOL_GPL(perf_event_update_userpage);
5858 static vm_fault_t perf_mmap_fault(struct vm_fault *vmf)
5860 struct perf_event *event = vmf->vma->vm_file->private_data;
5861 struct perf_buffer *rb;
5862 vm_fault_t ret = VM_FAULT_SIGBUS;
5864 if (vmf->flags & FAULT_FLAG_MKWRITE) {
5865 if (vmf->pgoff == 0)
5871 rb = rcu_dereference(event->rb);
5875 if (vmf->pgoff && (vmf->flags & FAULT_FLAG_WRITE))
5878 vmf->page = perf_mmap_to_page(rb, vmf->pgoff);
5882 get_page(vmf->page);
5883 vmf->page->mapping = vmf->vma->vm_file->f_mapping;
5884 vmf->page->index = vmf->pgoff;
5893 static void ring_buffer_attach(struct perf_event *event,
5894 struct perf_buffer *rb)
5896 struct perf_buffer *old_rb = NULL;
5897 unsigned long flags;
5901 * Should be impossible, we set this when removing
5902 * event->rb_entry and wait/clear when adding event->rb_entry.
5904 WARN_ON_ONCE(event->rcu_pending);
5907 spin_lock_irqsave(&old_rb->event_lock, flags);
5908 list_del_rcu(&event->rb_entry);
5909 spin_unlock_irqrestore(&old_rb->event_lock, flags);
5911 event->rcu_batches = get_state_synchronize_rcu();
5912 event->rcu_pending = 1;
5916 if (event->rcu_pending) {
5917 cond_synchronize_rcu(event->rcu_batches);
5918 event->rcu_pending = 0;
5921 spin_lock_irqsave(&rb->event_lock, flags);
5922 list_add_rcu(&event->rb_entry, &rb->event_list);
5923 spin_unlock_irqrestore(&rb->event_lock, flags);
5927 * Avoid racing with perf_mmap_close(AUX): stop the event
5928 * before swizzling the event::rb pointer; if it's getting
5929 * unmapped, its aux_mmap_count will be 0 and it won't
5930 * restart. See the comment in __perf_pmu_output_stop().
5932 * Data will inevitably be lost when set_output is done in
5933 * mid-air, but then again, whoever does it like this is
5934 * not in for the data anyway.
5937 perf_event_stop(event, 0);
5939 rcu_assign_pointer(event->rb, rb);
5942 ring_buffer_put(old_rb);
5944 * Since we detached before setting the new rb, so that we
5945 * could attach the new rb, we could have missed a wakeup.
5948 wake_up_all(&event->waitq);
5952 static void ring_buffer_wakeup(struct perf_event *event)
5954 struct perf_buffer *rb;
5957 rb = rcu_dereference(event->rb);
5959 list_for_each_entry_rcu(event, &rb->event_list, rb_entry)
5960 wake_up_all(&event->waitq);
5965 struct perf_buffer *ring_buffer_get(struct perf_event *event)
5967 struct perf_buffer *rb;
5970 rb = rcu_dereference(event->rb);
5972 if (!refcount_inc_not_zero(&rb->refcount))
5980 void ring_buffer_put(struct perf_buffer *rb)
5982 if (!refcount_dec_and_test(&rb->refcount))
5985 WARN_ON_ONCE(!list_empty(&rb->event_list));
5987 call_rcu(&rb->rcu_head, rb_free_rcu);
5990 static void perf_mmap_open(struct vm_area_struct *vma)
5992 struct perf_event *event = vma->vm_file->private_data;
5994 atomic_inc(&event->mmap_count);
5995 atomic_inc(&event->rb->mmap_count);
5998 atomic_inc(&event->rb->aux_mmap_count);
6000 if (event->pmu->event_mapped)
6001 event->pmu->event_mapped(event, vma->vm_mm);
6004 static void perf_pmu_output_stop(struct perf_event *event);
6007 * A buffer can be mmap()ed multiple times; either directly through the same
6008 * event, or through other events by use of perf_event_set_output().
6010 * In order to undo the VM accounting done by perf_mmap() we need to destroy
6011 * the buffer here, where we still have a VM context. This means we need
6012 * to detach all events redirecting to us.
6014 static void perf_mmap_close(struct vm_area_struct *vma)
6016 struct perf_event *event = vma->vm_file->private_data;
6017 struct perf_buffer *rb = ring_buffer_get(event);
6018 struct user_struct *mmap_user = rb->mmap_user;
6019 int mmap_locked = rb->mmap_locked;
6020 unsigned long size = perf_data_size(rb);
6021 bool detach_rest = false;
6023 if (event->pmu->event_unmapped)
6024 event->pmu->event_unmapped(event, vma->vm_mm);
6027 * rb->aux_mmap_count will always drop before rb->mmap_count and
6028 * event->mmap_count, so it is ok to use event->mmap_mutex to
6029 * serialize with perf_mmap here.
6031 if (rb_has_aux(rb) && vma->vm_pgoff == rb->aux_pgoff &&
6032 atomic_dec_and_mutex_lock(&rb->aux_mmap_count, &event->mmap_mutex)) {
6034 * Stop all AUX events that are writing to this buffer,
6035 * so that we can free its AUX pages and corresponding PMU
6036 * data. Note that after rb::aux_mmap_count dropped to zero,
6037 * they won't start any more (see perf_aux_output_begin()).
6039 perf_pmu_output_stop(event);
6041 /* now it's safe to free the pages */
6042 atomic_long_sub(rb->aux_nr_pages - rb->aux_mmap_locked, &mmap_user->locked_vm);
6043 atomic64_sub(rb->aux_mmap_locked, &vma->vm_mm->pinned_vm);
6045 /* this has to be the last one */
6047 WARN_ON_ONCE(refcount_read(&rb->aux_refcount));
6049 mutex_unlock(&event->mmap_mutex);
6052 if (atomic_dec_and_test(&rb->mmap_count))
6055 if (!atomic_dec_and_mutex_lock(&event->mmap_count, &event->mmap_mutex))
6058 ring_buffer_attach(event, NULL);
6059 mutex_unlock(&event->mmap_mutex);
6061 /* If there's still other mmap()s of this buffer, we're done. */
6066 * No other mmap()s, detach from all other events that might redirect
6067 * into the now unreachable buffer. Somewhat complicated by the
6068 * fact that rb::event_lock otherwise nests inside mmap_mutex.
6072 list_for_each_entry_rcu(event, &rb->event_list, rb_entry) {
6073 if (!atomic_long_inc_not_zero(&event->refcount)) {
6075 * This event is en-route to free_event() which will
6076 * detach it and remove it from the list.
6082 mutex_lock(&event->mmap_mutex);
6084 * Check we didn't race with perf_event_set_output() which can
6085 * swizzle the rb from under us while we were waiting to
6086 * acquire mmap_mutex.
6088 * If we find a different rb; ignore this event, a next
6089 * iteration will no longer find it on the list. We have to
6090 * still restart the iteration to make sure we're not now
6091 * iterating the wrong list.
6093 if (event->rb == rb)
6094 ring_buffer_attach(event, NULL);
6096 mutex_unlock(&event->mmap_mutex);
6100 * Restart the iteration; either we're on the wrong list or
6101 * destroyed its integrity by doing a deletion.
6108 * It could be there's still a few 0-ref events on the list; they'll
6109 * get cleaned up by free_event() -- they'll also still have their
6110 * ref on the rb and will free it whenever they are done with it.
6112 * Aside from that, this buffer is 'fully' detached and unmapped,
6113 * undo the VM accounting.
6116 atomic_long_sub((size >> PAGE_SHIFT) + 1 - mmap_locked,
6117 &mmap_user->locked_vm);
6118 atomic64_sub(mmap_locked, &vma->vm_mm->pinned_vm);
6119 free_uid(mmap_user);
6122 ring_buffer_put(rb); /* could be last */
6125 static const struct vm_operations_struct perf_mmap_vmops = {
6126 .open = perf_mmap_open,
6127 .close = perf_mmap_close, /* non mergeable */
6128 .fault = perf_mmap_fault,
6129 .page_mkwrite = perf_mmap_fault,
6132 static int perf_mmap(struct file *file, struct vm_area_struct *vma)
6134 struct perf_event *event = file->private_data;
6135 unsigned long user_locked, user_lock_limit;
6136 struct user_struct *user = current_user();
6137 struct perf_buffer *rb = NULL;
6138 unsigned long locked, lock_limit;
6139 unsigned long vma_size;
6140 unsigned long nr_pages;
6141 long user_extra = 0, extra = 0;
6142 int ret = 0, flags = 0;
6145 * Don't allow mmap() of inherited per-task counters. This would
6146 * create a performance issue due to all children writing to the
6149 if (event->cpu == -1 && event->attr.inherit)
6152 if (!(vma->vm_flags & VM_SHARED))
6155 ret = security_perf_event_read(event);
6159 vma_size = vma->vm_end - vma->vm_start;
6161 if (vma->vm_pgoff == 0) {
6162 nr_pages = (vma_size / PAGE_SIZE) - 1;
6165 * AUX area mapping: if rb->aux_nr_pages != 0, it's already
6166 * mapped, all subsequent mappings should have the same size
6167 * and offset. Must be above the normal perf buffer.
6169 u64 aux_offset, aux_size;
6174 nr_pages = vma_size / PAGE_SIZE;
6176 mutex_lock(&event->mmap_mutex);
6183 aux_offset = READ_ONCE(rb->user_page->aux_offset);
6184 aux_size = READ_ONCE(rb->user_page->aux_size);
6186 if (aux_offset < perf_data_size(rb) + PAGE_SIZE)
6189 if (aux_offset != vma->vm_pgoff << PAGE_SHIFT)
6192 /* already mapped with a different offset */
6193 if (rb_has_aux(rb) && rb->aux_pgoff != vma->vm_pgoff)
6196 if (aux_size != vma_size || aux_size != nr_pages * PAGE_SIZE)
6199 /* already mapped with a different size */
6200 if (rb_has_aux(rb) && rb->aux_nr_pages != nr_pages)
6203 if (!is_power_of_2(nr_pages))
6206 if (!atomic_inc_not_zero(&rb->mmap_count))
6209 if (rb_has_aux(rb)) {
6210 atomic_inc(&rb->aux_mmap_count);
6215 atomic_set(&rb->aux_mmap_count, 1);
6216 user_extra = nr_pages;
6222 * If we have rb pages ensure they're a power-of-two number, so we
6223 * can do bitmasks instead of modulo.
6225 if (nr_pages != 0 && !is_power_of_2(nr_pages))
6228 if (vma_size != PAGE_SIZE * (1 + nr_pages))
6231 WARN_ON_ONCE(event->ctx->parent_ctx);
6233 mutex_lock(&event->mmap_mutex);
6235 if (event->rb->nr_pages != nr_pages) {
6240 if (!atomic_inc_not_zero(&event->rb->mmap_count)) {
6242 * Raced against perf_mmap_close() through
6243 * perf_event_set_output(). Try again, hope for better
6246 mutex_unlock(&event->mmap_mutex);
6253 user_extra = nr_pages + 1;
6256 user_lock_limit = sysctl_perf_event_mlock >> (PAGE_SHIFT - 10);
6259 * Increase the limit linearly with more CPUs:
6261 user_lock_limit *= num_online_cpus();
6263 user_locked = atomic_long_read(&user->locked_vm);
6266 * sysctl_perf_event_mlock may have changed, so that
6267 * user->locked_vm > user_lock_limit
6269 if (user_locked > user_lock_limit)
6270 user_locked = user_lock_limit;
6271 user_locked += user_extra;
6273 if (user_locked > user_lock_limit) {
6275 * charge locked_vm until it hits user_lock_limit;
6276 * charge the rest from pinned_vm
6278 extra = user_locked - user_lock_limit;
6279 user_extra -= extra;
6282 lock_limit = rlimit(RLIMIT_MEMLOCK);
6283 lock_limit >>= PAGE_SHIFT;
6284 locked = atomic64_read(&vma->vm_mm->pinned_vm) + extra;
6286 if ((locked > lock_limit) && perf_is_paranoid() &&
6287 !capable(CAP_IPC_LOCK)) {
6292 WARN_ON(!rb && event->rb);
6294 if (vma->vm_flags & VM_WRITE)
6295 flags |= RING_BUFFER_WRITABLE;
6298 rb = rb_alloc(nr_pages,
6299 event->attr.watermark ? event->attr.wakeup_watermark : 0,
6307 atomic_set(&rb->mmap_count, 1);
6308 rb->mmap_user = get_current_user();
6309 rb->mmap_locked = extra;
6311 ring_buffer_attach(event, rb);
6313 perf_event_init_userpage(event);
6314 perf_event_update_userpage(event);
6316 ret = rb_alloc_aux(rb, event, vma->vm_pgoff, nr_pages,
6317 event->attr.aux_watermark, flags);
6319 rb->aux_mmap_locked = extra;
6324 atomic_long_add(user_extra, &user->locked_vm);
6325 atomic64_add(extra, &vma->vm_mm->pinned_vm);
6327 atomic_inc(&event->mmap_count);
6329 atomic_dec(&rb->mmap_count);
6332 mutex_unlock(&event->mmap_mutex);
6335 * Since pinned accounting is per vm we cannot allow fork() to copy our
6338 vma->vm_flags |= VM_DONTCOPY | VM_DONTEXPAND | VM_DONTDUMP;
6339 vma->vm_ops = &perf_mmap_vmops;
6341 if (event->pmu->event_mapped)
6342 event->pmu->event_mapped(event, vma->vm_mm);
6347 static int perf_fasync(int fd, struct file *filp, int on)
6349 struct inode *inode = file_inode(filp);
6350 struct perf_event *event = filp->private_data;
6354 retval = fasync_helper(fd, filp, on, &event->fasync);
6355 inode_unlock(inode);
6363 static const struct file_operations perf_fops = {
6364 .llseek = no_llseek,
6365 .release = perf_release,
6368 .unlocked_ioctl = perf_ioctl,
6369 .compat_ioctl = perf_compat_ioctl,
6371 .fasync = perf_fasync,
6377 * If there's data, ensure we set the poll() state and publish everything
6378 * to user-space before waking everybody up.
6381 static inline struct fasync_struct **perf_event_fasync(struct perf_event *event)
6383 /* only the parent has fasync state */
6385 event = event->parent;
6386 return &event->fasync;
6389 void perf_event_wakeup(struct perf_event *event)
6391 ring_buffer_wakeup(event);
6393 if (event->pending_kill) {
6394 kill_fasync(perf_event_fasync(event), SIGIO, event->pending_kill);
6395 event->pending_kill = 0;
6399 static void perf_sigtrap(struct perf_event *event)
6402 * We'd expect this to only occur if the irq_work is delayed and either
6403 * ctx->task or current has changed in the meantime. This can be the
6404 * case on architectures that do not implement arch_irq_work_raise().
6406 if (WARN_ON_ONCE(event->ctx->task != current))
6410 * perf_pending_event() can race with the task exiting.
6412 if (current->flags & PF_EXITING)
6415 force_sig_perf((void __user *)event->pending_addr,
6416 event->attr.type, event->attr.sig_data);
6419 static void perf_pending_event_disable(struct perf_event *event)
6421 int cpu = READ_ONCE(event->pending_disable);
6426 if (cpu == smp_processor_id()) {
6427 WRITE_ONCE(event->pending_disable, -1);
6429 if (event->attr.sigtrap) {
6430 perf_sigtrap(event);
6431 atomic_set_release(&event->event_limit, 1); /* rearm event */
6435 perf_event_disable_local(event);
6442 * perf_event_disable_inatomic()
6443 * @pending_disable = CPU-A;
6447 * @pending_disable = -1;
6450 * perf_event_disable_inatomic()
6451 * @pending_disable = CPU-B;
6452 * irq_work_queue(); // FAILS
6455 * perf_pending_event()
6457 * But the event runs on CPU-B and wants disabling there.
6459 irq_work_queue_on(&event->pending, cpu);
6462 static void perf_pending_event(struct irq_work *entry)
6464 struct perf_event *event = container_of(entry, struct perf_event, pending);
6467 rctx = perf_swevent_get_recursion_context();
6469 * If we 'fail' here, that's OK, it means recursion is already disabled
6470 * and we won't recurse 'further'.
6473 perf_pending_event_disable(event);
6475 if (event->pending_wakeup) {
6476 event->pending_wakeup = 0;
6477 perf_event_wakeup(event);
6481 perf_swevent_put_recursion_context(rctx);
6485 * We assume there is only KVM supporting the callbacks.
6486 * Later on, we might change it to a list if there is
6487 * another virtualization implementation supporting the callbacks.
6489 struct perf_guest_info_callbacks *perf_guest_cbs;
6491 int perf_register_guest_info_callbacks(struct perf_guest_info_callbacks *cbs)
6493 perf_guest_cbs = cbs;
6496 EXPORT_SYMBOL_GPL(perf_register_guest_info_callbacks);
6498 int perf_unregister_guest_info_callbacks(struct perf_guest_info_callbacks *cbs)
6500 perf_guest_cbs = NULL;
6503 EXPORT_SYMBOL_GPL(perf_unregister_guest_info_callbacks);
6506 perf_output_sample_regs(struct perf_output_handle *handle,
6507 struct pt_regs *regs, u64 mask)
6510 DECLARE_BITMAP(_mask, 64);
6512 bitmap_from_u64(_mask, mask);
6513 for_each_set_bit(bit, _mask, sizeof(mask) * BITS_PER_BYTE) {
6516 val = perf_reg_value(regs, bit);
6517 perf_output_put(handle, val);
6521 static void perf_sample_regs_user(struct perf_regs *regs_user,
6522 struct pt_regs *regs)
6524 if (user_mode(regs)) {
6525 regs_user->abi = perf_reg_abi(current);
6526 regs_user->regs = regs;
6527 } else if (!(current->flags & PF_KTHREAD)) {
6528 perf_get_regs_user(regs_user, regs);
6530 regs_user->abi = PERF_SAMPLE_REGS_ABI_NONE;
6531 regs_user->regs = NULL;
6535 static void perf_sample_regs_intr(struct perf_regs *regs_intr,
6536 struct pt_regs *regs)
6538 regs_intr->regs = regs;
6539 regs_intr->abi = perf_reg_abi(current);
6544 * Get remaining task size from user stack pointer.
6546 * It'd be better to take stack vma map and limit this more
6547 * precisely, but there's no way to get it safely under interrupt,
6548 * so using TASK_SIZE as limit.
6550 static u64 perf_ustack_task_size(struct pt_regs *regs)
6552 unsigned long addr = perf_user_stack_pointer(regs);
6554 if (!addr || addr >= TASK_SIZE)
6557 return TASK_SIZE - addr;
6561 perf_sample_ustack_size(u16 stack_size, u16 header_size,
6562 struct pt_regs *regs)
6566 /* No regs, no stack pointer, no dump. */
6571 * Check if we fit in with the requested stack size into the:
6573 * If we don't, we limit the size to the TASK_SIZE.
6575 * - remaining sample size
6576 * If we don't, we customize the stack size to
6577 * fit in to the remaining sample size.
6580 task_size = min((u64) USHRT_MAX, perf_ustack_task_size(regs));
6581 stack_size = min(stack_size, (u16) task_size);
6583 /* Current header size plus static size and dynamic size. */
6584 header_size += 2 * sizeof(u64);
6586 /* Do we fit in with the current stack dump size? */
6587 if ((u16) (header_size + stack_size) < header_size) {
6589 * If we overflow the maximum size for the sample,
6590 * we customize the stack dump size to fit in.
6592 stack_size = USHRT_MAX - header_size - sizeof(u64);
6593 stack_size = round_up(stack_size, sizeof(u64));
6600 perf_output_sample_ustack(struct perf_output_handle *handle, u64 dump_size,
6601 struct pt_regs *regs)
6603 /* Case of a kernel thread, nothing to dump */
6606 perf_output_put(handle, size);
6616 * - the size requested by user or the best one we can fit
6617 * in to the sample max size
6619 * - user stack dump data
6621 * - the actual dumped size
6625 perf_output_put(handle, dump_size);
6628 sp = perf_user_stack_pointer(regs);
6629 fs = force_uaccess_begin();
6630 rem = __output_copy_user(handle, (void *) sp, dump_size);
6631 force_uaccess_end(fs);
6632 dyn_size = dump_size - rem;
6634 perf_output_skip(handle, rem);
6637 perf_output_put(handle, dyn_size);
6641 static unsigned long perf_prepare_sample_aux(struct perf_event *event,
6642 struct perf_sample_data *data,
6645 struct perf_event *sampler = event->aux_event;
6646 struct perf_buffer *rb;
6653 if (WARN_ON_ONCE(READ_ONCE(sampler->state) != PERF_EVENT_STATE_ACTIVE))
6656 if (WARN_ON_ONCE(READ_ONCE(sampler->oncpu) != smp_processor_id()))
6659 rb = ring_buffer_get(sampler->parent ? sampler->parent : sampler);
6664 * If this is an NMI hit inside sampling code, don't take
6665 * the sample. See also perf_aux_sample_output().
6667 if (READ_ONCE(rb->aux_in_sampling)) {
6670 size = min_t(size_t, size, perf_aux_size(rb));
6671 data->aux_size = ALIGN(size, sizeof(u64));
6673 ring_buffer_put(rb);
6676 return data->aux_size;
6679 long perf_pmu_snapshot_aux(struct perf_buffer *rb,
6680 struct perf_event *event,
6681 struct perf_output_handle *handle,
6684 unsigned long flags;
6688 * Normal ->start()/->stop() callbacks run in IRQ mode in scheduler
6689 * paths. If we start calling them in NMI context, they may race with
6690 * the IRQ ones, that is, for example, re-starting an event that's just
6691 * been stopped, which is why we're using a separate callback that
6692 * doesn't change the event state.
6694 * IRQs need to be disabled to prevent IPIs from racing with us.
6696 local_irq_save(flags);
6698 * Guard against NMI hits inside the critical section;
6699 * see also perf_prepare_sample_aux().
6701 WRITE_ONCE(rb->aux_in_sampling, 1);
6704 ret = event->pmu->snapshot_aux(event, handle, size);
6707 WRITE_ONCE(rb->aux_in_sampling, 0);
6708 local_irq_restore(flags);
6713 static void perf_aux_sample_output(struct perf_event *event,
6714 struct perf_output_handle *handle,
6715 struct perf_sample_data *data)
6717 struct perf_event *sampler = event->aux_event;
6718 struct perf_buffer *rb;
6722 if (WARN_ON_ONCE(!sampler || !data->aux_size))
6725 rb = ring_buffer_get(sampler->parent ? sampler->parent : sampler);
6729 size = perf_pmu_snapshot_aux(rb, sampler, handle, data->aux_size);
6732 * An error here means that perf_output_copy() failed (returned a
6733 * non-zero surplus that it didn't copy), which in its current
6734 * enlightened implementation is not possible. If that changes, we'd
6737 if (WARN_ON_ONCE(size < 0))
6741 * The pad comes from ALIGN()ing data->aux_size up to u64 in
6742 * perf_prepare_sample_aux(), so should not be more than that.
6744 pad = data->aux_size - size;
6745 if (WARN_ON_ONCE(pad >= sizeof(u64)))
6750 perf_output_copy(handle, &zero, pad);
6754 ring_buffer_put(rb);
6757 static void __perf_event_header__init_id(struct perf_event_header *header,
6758 struct perf_sample_data *data,
6759 struct perf_event *event)
6761 u64 sample_type = event->attr.sample_type;
6763 data->type = sample_type;
6764 header->size += event->id_header_size;
6766 if (sample_type & PERF_SAMPLE_TID) {
6767 /* namespace issues */
6768 data->tid_entry.pid = perf_event_pid(event, current);
6769 data->tid_entry.tid = perf_event_tid(event, current);
6772 if (sample_type & PERF_SAMPLE_TIME)
6773 data->time = perf_event_clock(event);
6775 if (sample_type & (PERF_SAMPLE_ID | PERF_SAMPLE_IDENTIFIER))
6776 data->id = primary_event_id(event);
6778 if (sample_type & PERF_SAMPLE_STREAM_ID)
6779 data->stream_id = event->id;
6781 if (sample_type & PERF_SAMPLE_CPU) {
6782 data->cpu_entry.cpu = raw_smp_processor_id();
6783 data->cpu_entry.reserved = 0;
6787 void perf_event_header__init_id(struct perf_event_header *header,
6788 struct perf_sample_data *data,
6789 struct perf_event *event)
6791 if (event->attr.sample_id_all)
6792 __perf_event_header__init_id(header, data, event);
6795 static void __perf_event__output_id_sample(struct perf_output_handle *handle,
6796 struct perf_sample_data *data)
6798 u64 sample_type = data->type;
6800 if (sample_type & PERF_SAMPLE_TID)
6801 perf_output_put(handle, data->tid_entry);
6803 if (sample_type & PERF_SAMPLE_TIME)
6804 perf_output_put(handle, data->time);
6806 if (sample_type & PERF_SAMPLE_ID)
6807 perf_output_put(handle, data->id);
6809 if (sample_type & PERF_SAMPLE_STREAM_ID)
6810 perf_output_put(handle, data->stream_id);
6812 if (sample_type & PERF_SAMPLE_CPU)
6813 perf_output_put(handle, data->cpu_entry);
6815 if (sample_type & PERF_SAMPLE_IDENTIFIER)
6816 perf_output_put(handle, data->id);
6819 void perf_event__output_id_sample(struct perf_event *event,
6820 struct perf_output_handle *handle,
6821 struct perf_sample_data *sample)
6823 if (event->attr.sample_id_all)
6824 __perf_event__output_id_sample(handle, sample);
6827 static void perf_output_read_one(struct perf_output_handle *handle,
6828 struct perf_event *event,
6829 u64 enabled, u64 running)
6831 u64 read_format = event->attr.read_format;
6835 values[n++] = perf_event_count(event);
6836 if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED) {
6837 values[n++] = enabled +
6838 atomic64_read(&event->child_total_time_enabled);
6840 if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING) {
6841 values[n++] = running +
6842 atomic64_read(&event->child_total_time_running);
6844 if (read_format & PERF_FORMAT_ID)
6845 values[n++] = primary_event_id(event);
6847 __output_copy(handle, values, n * sizeof(u64));
6850 static void perf_output_read_group(struct perf_output_handle *handle,
6851 struct perf_event *event,
6852 u64 enabled, u64 running)
6854 struct perf_event *leader = event->group_leader, *sub;
6855 u64 read_format = event->attr.read_format;
6859 values[n++] = 1 + leader->nr_siblings;
6861 if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED)
6862 values[n++] = enabled;
6864 if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING)
6865 values[n++] = running;
6867 if ((leader != event) &&
6868 (leader->state == PERF_EVENT_STATE_ACTIVE))
6869 leader->pmu->read(leader);
6871 values[n++] = perf_event_count(leader);
6872 if (read_format & PERF_FORMAT_ID)
6873 values[n++] = primary_event_id(leader);
6875 __output_copy(handle, values, n * sizeof(u64));
6877 for_each_sibling_event(sub, leader) {
6880 if ((sub != event) &&
6881 (sub->state == PERF_EVENT_STATE_ACTIVE))
6882 sub->pmu->read(sub);
6884 values[n++] = perf_event_count(sub);
6885 if (read_format & PERF_FORMAT_ID)
6886 values[n++] = primary_event_id(sub);
6888 __output_copy(handle, values, n * sizeof(u64));
6892 #define PERF_FORMAT_TOTAL_TIMES (PERF_FORMAT_TOTAL_TIME_ENABLED|\
6893 PERF_FORMAT_TOTAL_TIME_RUNNING)
6896 * XXX PERF_SAMPLE_READ vs inherited events seems difficult.
6898 * The problem is that its both hard and excessively expensive to iterate the
6899 * child list, not to mention that its impossible to IPI the children running
6900 * on another CPU, from interrupt/NMI context.
6902 static void perf_output_read(struct perf_output_handle *handle,
6903 struct perf_event *event)
6905 u64 enabled = 0, running = 0, now;
6906 u64 read_format = event->attr.read_format;
6909 * compute total_time_enabled, total_time_running
6910 * based on snapshot values taken when the event
6911 * was last scheduled in.
6913 * we cannot simply called update_context_time()
6914 * because of locking issue as we are called in
6917 if (read_format & PERF_FORMAT_TOTAL_TIMES)
6918 calc_timer_values(event, &now, &enabled, &running);
6920 if (event->attr.read_format & PERF_FORMAT_GROUP)
6921 perf_output_read_group(handle, event, enabled, running);
6923 perf_output_read_one(handle, event, enabled, running);
6926 static inline bool perf_sample_save_hw_index(struct perf_event *event)
6928 return event->attr.branch_sample_type & PERF_SAMPLE_BRANCH_HW_INDEX;
6931 void perf_output_sample(struct perf_output_handle *handle,
6932 struct perf_event_header *header,
6933 struct perf_sample_data *data,
6934 struct perf_event *event)
6936 u64 sample_type = data->type;
6938 perf_output_put(handle, *header);
6940 if (sample_type & PERF_SAMPLE_IDENTIFIER)
6941 perf_output_put(handle, data->id);
6943 if (sample_type & PERF_SAMPLE_IP)
6944 perf_output_put(handle, data->ip);
6946 if (sample_type & PERF_SAMPLE_TID)
6947 perf_output_put(handle, data->tid_entry);
6949 if (sample_type & PERF_SAMPLE_TIME)
6950 perf_output_put(handle, data->time);
6952 if (sample_type & PERF_SAMPLE_ADDR)
6953 perf_output_put(handle, data->addr);
6955 if (sample_type & PERF_SAMPLE_ID)
6956 perf_output_put(handle, data->id);
6958 if (sample_type & PERF_SAMPLE_STREAM_ID)
6959 perf_output_put(handle, data->stream_id);
6961 if (sample_type & PERF_SAMPLE_CPU)
6962 perf_output_put(handle, data->cpu_entry);
6964 if (sample_type & PERF_SAMPLE_PERIOD)
6965 perf_output_put(handle, data->period);
6967 if (sample_type & PERF_SAMPLE_READ)
6968 perf_output_read(handle, event);
6970 if (sample_type & PERF_SAMPLE_CALLCHAIN) {
6973 size += data->callchain->nr;
6974 size *= sizeof(u64);
6975 __output_copy(handle, data->callchain, size);
6978 if (sample_type & PERF_SAMPLE_RAW) {
6979 struct perf_raw_record *raw = data->raw;
6982 struct perf_raw_frag *frag = &raw->frag;
6984 perf_output_put(handle, raw->size);
6987 __output_custom(handle, frag->copy,
6988 frag->data, frag->size);
6990 __output_copy(handle, frag->data,
6993 if (perf_raw_frag_last(frag))
6998 __output_skip(handle, NULL, frag->pad);
7004 .size = sizeof(u32),
7007 perf_output_put(handle, raw);
7011 if (sample_type & PERF_SAMPLE_BRANCH_STACK) {
7012 if (data->br_stack) {
7015 size = data->br_stack->nr
7016 * sizeof(struct perf_branch_entry);
7018 perf_output_put(handle, data->br_stack->nr);
7019 if (perf_sample_save_hw_index(event))
7020 perf_output_put(handle, data->br_stack->hw_idx);
7021 perf_output_copy(handle, data->br_stack->entries, size);
7024 * we always store at least the value of nr
7027 perf_output_put(handle, nr);
7031 if (sample_type & PERF_SAMPLE_REGS_USER) {
7032 u64 abi = data->regs_user.abi;
7035 * If there are no regs to dump, notice it through
7036 * first u64 being zero (PERF_SAMPLE_REGS_ABI_NONE).
7038 perf_output_put(handle, abi);
7041 u64 mask = event->attr.sample_regs_user;
7042 perf_output_sample_regs(handle,
7043 data->regs_user.regs,
7048 if (sample_type & PERF_SAMPLE_STACK_USER) {
7049 perf_output_sample_ustack(handle,
7050 data->stack_user_size,
7051 data->regs_user.regs);
7054 if (sample_type & PERF_SAMPLE_WEIGHT_TYPE)
7055 perf_output_put(handle, data->weight.full);
7057 if (sample_type & PERF_SAMPLE_DATA_SRC)
7058 perf_output_put(handle, data->data_src.val);
7060 if (sample_type & PERF_SAMPLE_TRANSACTION)
7061 perf_output_put(handle, data->txn);
7063 if (sample_type & PERF_SAMPLE_REGS_INTR) {
7064 u64 abi = data->regs_intr.abi;
7066 * If there are no regs to dump, notice it through
7067 * first u64 being zero (PERF_SAMPLE_REGS_ABI_NONE).
7069 perf_output_put(handle, abi);
7072 u64 mask = event->attr.sample_regs_intr;
7074 perf_output_sample_regs(handle,
7075 data->regs_intr.regs,
7080 if (sample_type & PERF_SAMPLE_PHYS_ADDR)
7081 perf_output_put(handle, data->phys_addr);
7083 if (sample_type & PERF_SAMPLE_CGROUP)
7084 perf_output_put(handle, data->cgroup);
7086 if (sample_type & PERF_SAMPLE_DATA_PAGE_SIZE)
7087 perf_output_put(handle, data->data_page_size);
7089 if (sample_type & PERF_SAMPLE_CODE_PAGE_SIZE)
7090 perf_output_put(handle, data->code_page_size);
7092 if (sample_type & PERF_SAMPLE_AUX) {
7093 perf_output_put(handle, data->aux_size);
7096 perf_aux_sample_output(event, handle, data);
7099 if (!event->attr.watermark) {
7100 int wakeup_events = event->attr.wakeup_events;
7102 if (wakeup_events) {
7103 struct perf_buffer *rb = handle->rb;
7104 int events = local_inc_return(&rb->events);
7106 if (events >= wakeup_events) {
7107 local_sub(wakeup_events, &rb->events);
7108 local_inc(&rb->wakeup);
7114 static u64 perf_virt_to_phys(u64 virt)
7117 struct page *p = NULL;
7122 if (virt >= TASK_SIZE) {
7123 /* If it's vmalloc()d memory, leave phys_addr as 0 */
7124 if (virt_addr_valid((void *)(uintptr_t)virt) &&
7125 !(virt >= VMALLOC_START && virt < VMALLOC_END))
7126 phys_addr = (u64)virt_to_phys((void *)(uintptr_t)virt);
7129 * Walking the pages tables for user address.
7130 * Interrupts are disabled, so it prevents any tear down
7131 * of the page tables.
7132 * Try IRQ-safe get_user_page_fast_only first.
7133 * If failed, leave phys_addr as 0.
7135 if (current->mm != NULL) {
7136 pagefault_disable();
7137 if (get_user_page_fast_only(virt, 0, &p))
7138 phys_addr = page_to_phys(p) + virt % PAGE_SIZE;
7150 * Return the pagetable size of a given virtual address.
7152 static u64 perf_get_pgtable_size(struct mm_struct *mm, unsigned long addr)
7156 #ifdef CONFIG_HAVE_FAST_GUP
7163 pgdp = pgd_offset(mm, addr);
7164 pgd = READ_ONCE(*pgdp);
7169 return pgd_leaf_size(pgd);
7171 p4dp = p4d_offset_lockless(pgdp, pgd, addr);
7172 p4d = READ_ONCE(*p4dp);
7173 if (!p4d_present(p4d))
7177 return p4d_leaf_size(p4d);
7179 pudp = pud_offset_lockless(p4dp, p4d, addr);
7180 pud = READ_ONCE(*pudp);
7181 if (!pud_present(pud))
7185 return pud_leaf_size(pud);
7187 pmdp = pmd_offset_lockless(pudp, pud, addr);
7188 pmd = READ_ONCE(*pmdp);
7189 if (!pmd_present(pmd))
7193 return pmd_leaf_size(pmd);
7195 ptep = pte_offset_map(&pmd, addr);
7196 pte = ptep_get_lockless(ptep);
7197 if (pte_present(pte))
7198 size = pte_leaf_size(pte);
7200 #endif /* CONFIG_HAVE_FAST_GUP */
7205 static u64 perf_get_page_size(unsigned long addr)
7207 struct mm_struct *mm;
7208 unsigned long flags;
7215 * Software page-table walkers must disable IRQs,
7216 * which prevents any tear down of the page tables.
7218 local_irq_save(flags);
7223 * For kernel threads and the like, use init_mm so that
7224 * we can find kernel memory.
7229 size = perf_get_pgtable_size(mm, addr);
7231 local_irq_restore(flags);
7236 static struct perf_callchain_entry __empty_callchain = { .nr = 0, };
7238 struct perf_callchain_entry *
7239 perf_callchain(struct perf_event *event, struct pt_regs *regs)
7241 bool kernel = !event->attr.exclude_callchain_kernel;
7242 bool user = !event->attr.exclude_callchain_user;
7243 /* Disallow cross-task user callchains. */
7244 bool crosstask = event->ctx->task && event->ctx->task != current;
7245 const u32 max_stack = event->attr.sample_max_stack;
7246 struct perf_callchain_entry *callchain;
7248 if (!kernel && !user)
7249 return &__empty_callchain;
7251 callchain = get_perf_callchain(regs, 0, kernel, user,
7252 max_stack, crosstask, true);
7253 return callchain ?: &__empty_callchain;
7256 void perf_prepare_sample(struct perf_event_header *header,
7257 struct perf_sample_data *data,
7258 struct perf_event *event,
7259 struct pt_regs *regs)
7261 u64 sample_type = event->attr.sample_type;
7263 header->type = PERF_RECORD_SAMPLE;
7264 header->size = sizeof(*header) + event->header_size;
7267 header->misc |= perf_misc_flags(regs);
7269 __perf_event_header__init_id(header, data, event);
7271 if (sample_type & (PERF_SAMPLE_IP | PERF_SAMPLE_CODE_PAGE_SIZE))
7272 data->ip = perf_instruction_pointer(regs);
7274 if (sample_type & PERF_SAMPLE_CALLCHAIN) {
7277 if (!(sample_type & __PERF_SAMPLE_CALLCHAIN_EARLY))
7278 data->callchain = perf_callchain(event, regs);
7280 size += data->callchain->nr;
7282 header->size += size * sizeof(u64);
7285 if (sample_type & PERF_SAMPLE_RAW) {
7286 struct perf_raw_record *raw = data->raw;
7290 struct perf_raw_frag *frag = &raw->frag;
7295 if (perf_raw_frag_last(frag))
7300 size = round_up(sum + sizeof(u32), sizeof(u64));
7301 raw->size = size - sizeof(u32);
7302 frag->pad = raw->size - sum;
7307 header->size += size;
7310 if (sample_type & PERF_SAMPLE_BRANCH_STACK) {
7311 int size = sizeof(u64); /* nr */
7312 if (data->br_stack) {
7313 if (perf_sample_save_hw_index(event))
7314 size += sizeof(u64);
7316 size += data->br_stack->nr
7317 * sizeof(struct perf_branch_entry);
7319 header->size += size;
7322 if (sample_type & (PERF_SAMPLE_REGS_USER | PERF_SAMPLE_STACK_USER))
7323 perf_sample_regs_user(&data->regs_user, regs);
7325 if (sample_type & PERF_SAMPLE_REGS_USER) {
7326 /* regs dump ABI info */
7327 int size = sizeof(u64);
7329 if (data->regs_user.regs) {
7330 u64 mask = event->attr.sample_regs_user;
7331 size += hweight64(mask) * sizeof(u64);
7334 header->size += size;
7337 if (sample_type & PERF_SAMPLE_STACK_USER) {
7339 * Either we need PERF_SAMPLE_STACK_USER bit to be always
7340 * processed as the last one or have additional check added
7341 * in case new sample type is added, because we could eat
7342 * up the rest of the sample size.
7344 u16 stack_size = event->attr.sample_stack_user;
7345 u16 size = sizeof(u64);
7347 stack_size = perf_sample_ustack_size(stack_size, header->size,
7348 data->regs_user.regs);
7351 * If there is something to dump, add space for the dump
7352 * itself and for the field that tells the dynamic size,
7353 * which is how many have been actually dumped.
7356 size += sizeof(u64) + stack_size;
7358 data->stack_user_size = stack_size;
7359 header->size += size;
7362 if (sample_type & PERF_SAMPLE_REGS_INTR) {
7363 /* regs dump ABI info */
7364 int size = sizeof(u64);
7366 perf_sample_regs_intr(&data->regs_intr, regs);
7368 if (data->regs_intr.regs) {
7369 u64 mask = event->attr.sample_regs_intr;
7371 size += hweight64(mask) * sizeof(u64);
7374 header->size += size;
7377 if (sample_type & PERF_SAMPLE_PHYS_ADDR)
7378 data->phys_addr = perf_virt_to_phys(data->addr);
7380 #ifdef CONFIG_CGROUP_PERF
7381 if (sample_type & PERF_SAMPLE_CGROUP) {
7382 struct cgroup *cgrp;
7384 /* protected by RCU */
7385 cgrp = task_css_check(current, perf_event_cgrp_id, 1)->cgroup;
7386 data->cgroup = cgroup_id(cgrp);
7391 * PERF_DATA_PAGE_SIZE requires PERF_SAMPLE_ADDR. If the user doesn't
7392 * require PERF_SAMPLE_ADDR, kernel implicitly retrieve the data->addr,
7393 * but the value will not dump to the userspace.
7395 if (sample_type & PERF_SAMPLE_DATA_PAGE_SIZE)
7396 data->data_page_size = perf_get_page_size(data->addr);
7398 if (sample_type & PERF_SAMPLE_CODE_PAGE_SIZE)
7399 data->code_page_size = perf_get_page_size(data->ip);
7401 if (sample_type & PERF_SAMPLE_AUX) {
7404 header->size += sizeof(u64); /* size */
7407 * Given the 16bit nature of header::size, an AUX sample can
7408 * easily overflow it, what with all the preceding sample bits.
7409 * Make sure this doesn't happen by using up to U16_MAX bytes
7410 * per sample in total (rounded down to 8 byte boundary).
7412 size = min_t(size_t, U16_MAX - header->size,
7413 event->attr.aux_sample_size);
7414 size = rounddown(size, 8);
7415 size = perf_prepare_sample_aux(event, data, size);
7417 WARN_ON_ONCE(size + header->size > U16_MAX);
7418 header->size += size;
7421 * If you're adding more sample types here, you likely need to do
7422 * something about the overflowing header::size, like repurpose the
7423 * lowest 3 bits of size, which should be always zero at the moment.
7424 * This raises a more important question, do we really need 512k sized
7425 * samples and why, so good argumentation is in order for whatever you
7428 WARN_ON_ONCE(header->size & 7);
7431 static __always_inline int
7432 __perf_event_output(struct perf_event *event,
7433 struct perf_sample_data *data,
7434 struct pt_regs *regs,
7435 int (*output_begin)(struct perf_output_handle *,
7436 struct perf_sample_data *,
7437 struct perf_event *,
7440 struct perf_output_handle handle;
7441 struct perf_event_header header;
7444 /* protect the callchain buffers */
7447 perf_prepare_sample(&header, data, event, regs);
7449 err = output_begin(&handle, data, event, header.size);
7453 perf_output_sample(&handle, &header, data, event);
7455 perf_output_end(&handle);
7463 perf_event_output_forward(struct perf_event *event,
7464 struct perf_sample_data *data,
7465 struct pt_regs *regs)
7467 __perf_event_output(event, data, regs, perf_output_begin_forward);
7471 perf_event_output_backward(struct perf_event *event,
7472 struct perf_sample_data *data,
7473 struct pt_regs *regs)
7475 __perf_event_output(event, data, regs, perf_output_begin_backward);
7479 perf_event_output(struct perf_event *event,
7480 struct perf_sample_data *data,
7481 struct pt_regs *regs)
7483 return __perf_event_output(event, data, regs, perf_output_begin);
7490 struct perf_read_event {
7491 struct perf_event_header header;
7498 perf_event_read_event(struct perf_event *event,
7499 struct task_struct *task)
7501 struct perf_output_handle handle;
7502 struct perf_sample_data sample;
7503 struct perf_read_event read_event = {
7505 .type = PERF_RECORD_READ,
7507 .size = sizeof(read_event) + event->read_size,
7509 .pid = perf_event_pid(event, task),
7510 .tid = perf_event_tid(event, task),
7514 perf_event_header__init_id(&read_event.header, &sample, event);
7515 ret = perf_output_begin(&handle, &sample, event, read_event.header.size);
7519 perf_output_put(&handle, read_event);
7520 perf_output_read(&handle, event);
7521 perf_event__output_id_sample(event, &handle, &sample);
7523 perf_output_end(&handle);
7526 typedef void (perf_iterate_f)(struct perf_event *event, void *data);
7529 perf_iterate_ctx(struct perf_event_context *ctx,
7530 perf_iterate_f output,
7531 void *data, bool all)
7533 struct perf_event *event;
7535 list_for_each_entry_rcu(event, &ctx->event_list, event_entry) {
7537 if (event->state < PERF_EVENT_STATE_INACTIVE)
7539 if (!event_filter_match(event))
7543 output(event, data);
7547 static void perf_iterate_sb_cpu(perf_iterate_f output, void *data)
7549 struct pmu_event_list *pel = this_cpu_ptr(&pmu_sb_events);
7550 struct perf_event *event;
7552 list_for_each_entry_rcu(event, &pel->list, sb_list) {
7554 * Skip events that are not fully formed yet; ensure that
7555 * if we observe event->ctx, both event and ctx will be
7556 * complete enough. See perf_install_in_context().
7558 if (!smp_load_acquire(&event->ctx))
7561 if (event->state < PERF_EVENT_STATE_INACTIVE)
7563 if (!event_filter_match(event))
7565 output(event, data);
7570 * Iterate all events that need to receive side-band events.
7572 * For new callers; ensure that account_pmu_sb_event() includes
7573 * your event, otherwise it might not get delivered.
7576 perf_iterate_sb(perf_iterate_f output, void *data,
7577 struct perf_event_context *task_ctx)
7579 struct perf_event_context *ctx;
7586 * If we have task_ctx != NULL we only notify the task context itself.
7587 * The task_ctx is set only for EXIT events before releasing task
7591 perf_iterate_ctx(task_ctx, output, data, false);
7595 perf_iterate_sb_cpu(output, data);
7597 for_each_task_context_nr(ctxn) {
7598 ctx = rcu_dereference(current->perf_event_ctxp[ctxn]);
7600 perf_iterate_ctx(ctx, output, data, false);
7608 * Clear all file-based filters at exec, they'll have to be
7609 * re-instated when/if these objects are mmapped again.
7611 static void perf_event_addr_filters_exec(struct perf_event *event, void *data)
7613 struct perf_addr_filters_head *ifh = perf_event_addr_filters(event);
7614 struct perf_addr_filter *filter;
7615 unsigned int restart = 0, count = 0;
7616 unsigned long flags;
7618 if (!has_addr_filter(event))
7621 raw_spin_lock_irqsave(&ifh->lock, flags);
7622 list_for_each_entry(filter, &ifh->list, entry) {
7623 if (filter->path.dentry) {
7624 event->addr_filter_ranges[count].start = 0;
7625 event->addr_filter_ranges[count].size = 0;
7633 event->addr_filters_gen++;
7634 raw_spin_unlock_irqrestore(&ifh->lock, flags);
7637 perf_event_stop(event, 1);
7640 void perf_event_exec(void)
7642 struct perf_event_context *ctx;
7645 for_each_task_context_nr(ctxn) {
7646 perf_event_enable_on_exec(ctxn);
7647 perf_event_remove_on_exec(ctxn);
7650 ctx = rcu_dereference(current->perf_event_ctxp[ctxn]);
7652 perf_iterate_ctx(ctx, perf_event_addr_filters_exec,
7659 struct remote_output {
7660 struct perf_buffer *rb;
7664 static void __perf_event_output_stop(struct perf_event *event, void *data)
7666 struct perf_event *parent = event->parent;
7667 struct remote_output *ro = data;
7668 struct perf_buffer *rb = ro->rb;
7669 struct stop_event_data sd = {
7673 if (!has_aux(event))
7680 * In case of inheritance, it will be the parent that links to the
7681 * ring-buffer, but it will be the child that's actually using it.
7683 * We are using event::rb to determine if the event should be stopped,
7684 * however this may race with ring_buffer_attach() (through set_output),
7685 * which will make us skip the event that actually needs to be stopped.
7686 * So ring_buffer_attach() has to stop an aux event before re-assigning
7689 if (rcu_dereference(parent->rb) == rb)
7690 ro->err = __perf_event_stop(&sd);
7693 static int __perf_pmu_output_stop(void *info)
7695 struct perf_event *event = info;
7696 struct pmu *pmu = event->ctx->pmu;
7697 struct perf_cpu_context *cpuctx = this_cpu_ptr(pmu->pmu_cpu_context);
7698 struct remote_output ro = {
7703 perf_iterate_ctx(&cpuctx->ctx, __perf_event_output_stop, &ro, false);
7704 if (cpuctx->task_ctx)
7705 perf_iterate_ctx(cpuctx->task_ctx, __perf_event_output_stop,
7712 static void perf_pmu_output_stop(struct perf_event *event)
7714 struct perf_event *iter;
7719 list_for_each_entry_rcu(iter, &event->rb->event_list, rb_entry) {
7721 * For per-CPU events, we need to make sure that neither they
7722 * nor their children are running; for cpu==-1 events it's
7723 * sufficient to stop the event itself if it's active, since
7724 * it can't have children.
7728 cpu = READ_ONCE(iter->oncpu);
7733 err = cpu_function_call(cpu, __perf_pmu_output_stop, event);
7734 if (err == -EAGAIN) {
7743 * task tracking -- fork/exit
7745 * enabled by: attr.comm | attr.mmap | attr.mmap2 | attr.mmap_data | attr.task
7748 struct perf_task_event {
7749 struct task_struct *task;
7750 struct perf_event_context *task_ctx;
7753 struct perf_event_header header;
7763 static int perf_event_task_match(struct perf_event *event)
7765 return event->attr.comm || event->attr.mmap ||
7766 event->attr.mmap2 || event->attr.mmap_data ||
7770 static void perf_event_task_output(struct perf_event *event,
7773 struct perf_task_event *task_event = data;
7774 struct perf_output_handle handle;
7775 struct perf_sample_data sample;
7776 struct task_struct *task = task_event->task;
7777 int ret, size = task_event->event_id.header.size;
7779 if (!perf_event_task_match(event))
7782 perf_event_header__init_id(&task_event->event_id.header, &sample, event);
7784 ret = perf_output_begin(&handle, &sample, event,
7785 task_event->event_id.header.size);
7789 task_event->event_id.pid = perf_event_pid(event, task);
7790 task_event->event_id.tid = perf_event_tid(event, task);
7792 if (task_event->event_id.header.type == PERF_RECORD_EXIT) {
7793 task_event->event_id.ppid = perf_event_pid(event,
7795 task_event->event_id.ptid = perf_event_pid(event,
7797 } else { /* PERF_RECORD_FORK */
7798 task_event->event_id.ppid = perf_event_pid(event, current);
7799 task_event->event_id.ptid = perf_event_tid(event, current);
7802 task_event->event_id.time = perf_event_clock(event);
7804 perf_output_put(&handle, task_event->event_id);
7806 perf_event__output_id_sample(event, &handle, &sample);
7808 perf_output_end(&handle);
7810 task_event->event_id.header.size = size;
7813 static void perf_event_task(struct task_struct *task,
7814 struct perf_event_context *task_ctx,
7817 struct perf_task_event task_event;
7819 if (!atomic_read(&nr_comm_events) &&
7820 !atomic_read(&nr_mmap_events) &&
7821 !atomic_read(&nr_task_events))
7824 task_event = (struct perf_task_event){
7826 .task_ctx = task_ctx,
7829 .type = new ? PERF_RECORD_FORK : PERF_RECORD_EXIT,
7831 .size = sizeof(task_event.event_id),
7841 perf_iterate_sb(perf_event_task_output,
7846 void perf_event_fork(struct task_struct *task)
7848 perf_event_task(task, NULL, 1);
7849 perf_event_namespaces(task);
7856 struct perf_comm_event {
7857 struct task_struct *task;
7862 struct perf_event_header header;
7869 static int perf_event_comm_match(struct perf_event *event)
7871 return event->attr.comm;
7874 static void perf_event_comm_output(struct perf_event *event,
7877 struct perf_comm_event *comm_event = data;
7878 struct perf_output_handle handle;
7879 struct perf_sample_data sample;
7880 int size = comm_event->event_id.header.size;
7883 if (!perf_event_comm_match(event))
7886 perf_event_header__init_id(&comm_event->event_id.header, &sample, event);
7887 ret = perf_output_begin(&handle, &sample, event,
7888 comm_event->event_id.header.size);
7893 comm_event->event_id.pid = perf_event_pid(event, comm_event->task);
7894 comm_event->event_id.tid = perf_event_tid(event, comm_event->task);
7896 perf_output_put(&handle, comm_event->event_id);
7897 __output_copy(&handle, comm_event->comm,
7898 comm_event->comm_size);
7900 perf_event__output_id_sample(event, &handle, &sample);
7902 perf_output_end(&handle);
7904 comm_event->event_id.header.size = size;
7907 static void perf_event_comm_event(struct perf_comm_event *comm_event)
7909 char comm[TASK_COMM_LEN];
7912 memset(comm, 0, sizeof(comm));
7913 strlcpy(comm, comm_event->task->comm, sizeof(comm));
7914 size = ALIGN(strlen(comm)+1, sizeof(u64));
7916 comm_event->comm = comm;
7917 comm_event->comm_size = size;
7919 comm_event->event_id.header.size = sizeof(comm_event->event_id) + size;
7921 perf_iterate_sb(perf_event_comm_output,
7926 void perf_event_comm(struct task_struct *task, bool exec)
7928 struct perf_comm_event comm_event;
7930 if (!atomic_read(&nr_comm_events))
7933 comm_event = (struct perf_comm_event){
7939 .type = PERF_RECORD_COMM,
7940 .misc = exec ? PERF_RECORD_MISC_COMM_EXEC : 0,
7948 perf_event_comm_event(&comm_event);
7952 * namespaces tracking
7955 struct perf_namespaces_event {
7956 struct task_struct *task;
7959 struct perf_event_header header;
7964 struct perf_ns_link_info link_info[NR_NAMESPACES];
7968 static int perf_event_namespaces_match(struct perf_event *event)
7970 return event->attr.namespaces;
7973 static void perf_event_namespaces_output(struct perf_event *event,
7976 struct perf_namespaces_event *namespaces_event = data;
7977 struct perf_output_handle handle;
7978 struct perf_sample_data sample;
7979 u16 header_size = namespaces_event->event_id.header.size;
7982 if (!perf_event_namespaces_match(event))
7985 perf_event_header__init_id(&namespaces_event->event_id.header,
7987 ret = perf_output_begin(&handle, &sample, event,
7988 namespaces_event->event_id.header.size);
7992 namespaces_event->event_id.pid = perf_event_pid(event,
7993 namespaces_event->task);
7994 namespaces_event->event_id.tid = perf_event_tid(event,
7995 namespaces_event->task);
7997 perf_output_put(&handle, namespaces_event->event_id);
7999 perf_event__output_id_sample(event, &handle, &sample);
8001 perf_output_end(&handle);
8003 namespaces_event->event_id.header.size = header_size;
8006 static void perf_fill_ns_link_info(struct perf_ns_link_info *ns_link_info,
8007 struct task_struct *task,
8008 const struct proc_ns_operations *ns_ops)
8010 struct path ns_path;
8011 struct inode *ns_inode;
8014 error = ns_get_path(&ns_path, task, ns_ops);
8016 ns_inode = ns_path.dentry->d_inode;
8017 ns_link_info->dev = new_encode_dev(ns_inode->i_sb->s_dev);
8018 ns_link_info->ino = ns_inode->i_ino;
8023 void perf_event_namespaces(struct task_struct *task)
8025 struct perf_namespaces_event namespaces_event;
8026 struct perf_ns_link_info *ns_link_info;
8028 if (!atomic_read(&nr_namespaces_events))
8031 namespaces_event = (struct perf_namespaces_event){
8035 .type = PERF_RECORD_NAMESPACES,
8037 .size = sizeof(namespaces_event.event_id),
8041 .nr_namespaces = NR_NAMESPACES,
8042 /* .link_info[NR_NAMESPACES] */
8046 ns_link_info = namespaces_event.event_id.link_info;
8048 perf_fill_ns_link_info(&ns_link_info[MNT_NS_INDEX],
8049 task, &mntns_operations);
8051 #ifdef CONFIG_USER_NS
8052 perf_fill_ns_link_info(&ns_link_info[USER_NS_INDEX],
8053 task, &userns_operations);
8055 #ifdef CONFIG_NET_NS
8056 perf_fill_ns_link_info(&ns_link_info[NET_NS_INDEX],
8057 task, &netns_operations);
8059 #ifdef CONFIG_UTS_NS
8060 perf_fill_ns_link_info(&ns_link_info[UTS_NS_INDEX],
8061 task, &utsns_operations);
8063 #ifdef CONFIG_IPC_NS
8064 perf_fill_ns_link_info(&ns_link_info[IPC_NS_INDEX],
8065 task, &ipcns_operations);
8067 #ifdef CONFIG_PID_NS
8068 perf_fill_ns_link_info(&ns_link_info[PID_NS_INDEX],
8069 task, &pidns_operations);
8071 #ifdef CONFIG_CGROUPS
8072 perf_fill_ns_link_info(&ns_link_info[CGROUP_NS_INDEX],
8073 task, &cgroupns_operations);
8076 perf_iterate_sb(perf_event_namespaces_output,
8084 #ifdef CONFIG_CGROUP_PERF
8086 struct perf_cgroup_event {
8090 struct perf_event_header header;
8096 static int perf_event_cgroup_match(struct perf_event *event)
8098 return event->attr.cgroup;
8101 static void perf_event_cgroup_output(struct perf_event *event, void *data)
8103 struct perf_cgroup_event *cgroup_event = data;
8104 struct perf_output_handle handle;
8105 struct perf_sample_data sample;
8106 u16 header_size = cgroup_event->event_id.header.size;
8109 if (!perf_event_cgroup_match(event))
8112 perf_event_header__init_id(&cgroup_event->event_id.header,
8114 ret = perf_output_begin(&handle, &sample, event,
8115 cgroup_event->event_id.header.size);
8119 perf_output_put(&handle, cgroup_event->event_id);
8120 __output_copy(&handle, cgroup_event->path, cgroup_event->path_size);
8122 perf_event__output_id_sample(event, &handle, &sample);
8124 perf_output_end(&handle);
8126 cgroup_event->event_id.header.size = header_size;
8129 static void perf_event_cgroup(struct cgroup *cgrp)
8131 struct perf_cgroup_event cgroup_event;
8132 char path_enomem[16] = "//enomem";
8136 if (!atomic_read(&nr_cgroup_events))
8139 cgroup_event = (struct perf_cgroup_event){
8142 .type = PERF_RECORD_CGROUP,
8144 .size = sizeof(cgroup_event.event_id),
8146 .id = cgroup_id(cgrp),
8150 pathname = kmalloc(PATH_MAX, GFP_KERNEL);
8151 if (pathname == NULL) {
8152 cgroup_event.path = path_enomem;
8154 /* just to be sure to have enough space for alignment */
8155 cgroup_path(cgrp, pathname, PATH_MAX - sizeof(u64));
8156 cgroup_event.path = pathname;
8160 * Since our buffer works in 8 byte units we need to align our string
8161 * size to a multiple of 8. However, we must guarantee the tail end is
8162 * zero'd out to avoid leaking random bits to userspace.
8164 size = strlen(cgroup_event.path) + 1;
8165 while (!IS_ALIGNED(size, sizeof(u64)))
8166 cgroup_event.path[size++] = '\0';
8168 cgroup_event.event_id.header.size += size;
8169 cgroup_event.path_size = size;
8171 perf_iterate_sb(perf_event_cgroup_output,
8184 struct perf_mmap_event {
8185 struct vm_area_struct *vma;
8187 const char *file_name;
8193 u8 build_id[BUILD_ID_SIZE_MAX];
8197 struct perf_event_header header;
8207 static int perf_event_mmap_match(struct perf_event *event,
8210 struct perf_mmap_event *mmap_event = data;
8211 struct vm_area_struct *vma = mmap_event->vma;
8212 int executable = vma->vm_flags & VM_EXEC;
8214 return (!executable && event->attr.mmap_data) ||
8215 (executable && (event->attr.mmap || event->attr.mmap2));
8218 static void perf_event_mmap_output(struct perf_event *event,
8221 struct perf_mmap_event *mmap_event = data;
8222 struct perf_output_handle handle;
8223 struct perf_sample_data sample;
8224 int size = mmap_event->event_id.header.size;
8225 u32 type = mmap_event->event_id.header.type;
8229 if (!perf_event_mmap_match(event, data))
8232 if (event->attr.mmap2) {
8233 mmap_event->event_id.header.type = PERF_RECORD_MMAP2;
8234 mmap_event->event_id.header.size += sizeof(mmap_event->maj);
8235 mmap_event->event_id.header.size += sizeof(mmap_event->min);
8236 mmap_event->event_id.header.size += sizeof(mmap_event->ino);
8237 mmap_event->event_id.header.size += sizeof(mmap_event->ino_generation);
8238 mmap_event->event_id.header.size += sizeof(mmap_event->prot);
8239 mmap_event->event_id.header.size += sizeof(mmap_event->flags);
8242 perf_event_header__init_id(&mmap_event->event_id.header, &sample, event);
8243 ret = perf_output_begin(&handle, &sample, event,
8244 mmap_event->event_id.header.size);
8248 mmap_event->event_id.pid = perf_event_pid(event, current);
8249 mmap_event->event_id.tid = perf_event_tid(event, current);
8251 use_build_id = event->attr.build_id && mmap_event->build_id_size;
8253 if (event->attr.mmap2 && use_build_id)
8254 mmap_event->event_id.header.misc |= PERF_RECORD_MISC_MMAP_BUILD_ID;
8256 perf_output_put(&handle, mmap_event->event_id);
8258 if (event->attr.mmap2) {
8260 u8 size[4] = { (u8) mmap_event->build_id_size, 0, 0, 0 };
8262 __output_copy(&handle, size, 4);
8263 __output_copy(&handle, mmap_event->build_id, BUILD_ID_SIZE_MAX);
8265 perf_output_put(&handle, mmap_event->maj);
8266 perf_output_put(&handle, mmap_event->min);
8267 perf_output_put(&handle, mmap_event->ino);
8268 perf_output_put(&handle, mmap_event->ino_generation);
8270 perf_output_put(&handle, mmap_event->prot);
8271 perf_output_put(&handle, mmap_event->flags);
8274 __output_copy(&handle, mmap_event->file_name,
8275 mmap_event->file_size);
8277 perf_event__output_id_sample(event, &handle, &sample);
8279 perf_output_end(&handle);
8281 mmap_event->event_id.header.size = size;
8282 mmap_event->event_id.header.type = type;
8285 static void perf_event_mmap_event(struct perf_mmap_event *mmap_event)
8287 struct vm_area_struct *vma = mmap_event->vma;
8288 struct file *file = vma->vm_file;
8289 int maj = 0, min = 0;
8290 u64 ino = 0, gen = 0;
8291 u32 prot = 0, flags = 0;
8297 if (vma->vm_flags & VM_READ)
8299 if (vma->vm_flags & VM_WRITE)
8301 if (vma->vm_flags & VM_EXEC)
8304 if (vma->vm_flags & VM_MAYSHARE)
8307 flags = MAP_PRIVATE;
8309 if (vma->vm_flags & VM_DENYWRITE)
8310 flags |= MAP_DENYWRITE;
8311 if (vma->vm_flags & VM_MAYEXEC)
8312 flags |= MAP_EXECUTABLE;
8313 if (vma->vm_flags & VM_LOCKED)
8314 flags |= MAP_LOCKED;
8315 if (is_vm_hugetlb_page(vma))
8316 flags |= MAP_HUGETLB;
8319 struct inode *inode;
8322 buf = kmalloc(PATH_MAX, GFP_KERNEL);
8328 * d_path() works from the end of the rb backwards, so we
8329 * need to add enough zero bytes after the string to handle
8330 * the 64bit alignment we do later.
8332 name = file_path(file, buf, PATH_MAX - sizeof(u64));
8337 inode = file_inode(vma->vm_file);
8338 dev = inode->i_sb->s_dev;
8340 gen = inode->i_generation;
8346 if (vma->vm_ops && vma->vm_ops->name) {
8347 name = (char *) vma->vm_ops->name(vma);
8352 name = (char *)arch_vma_name(vma);
8356 if (vma->vm_start <= vma->vm_mm->start_brk &&
8357 vma->vm_end >= vma->vm_mm->brk) {
8361 if (vma->vm_start <= vma->vm_mm->start_stack &&
8362 vma->vm_end >= vma->vm_mm->start_stack) {
8372 strlcpy(tmp, name, sizeof(tmp));
8376 * Since our buffer works in 8 byte units we need to align our string
8377 * size to a multiple of 8. However, we must guarantee the tail end is
8378 * zero'd out to avoid leaking random bits to userspace.
8380 size = strlen(name)+1;
8381 while (!IS_ALIGNED(size, sizeof(u64)))
8382 name[size++] = '\0';
8384 mmap_event->file_name = name;
8385 mmap_event->file_size = size;
8386 mmap_event->maj = maj;
8387 mmap_event->min = min;
8388 mmap_event->ino = ino;
8389 mmap_event->ino_generation = gen;
8390 mmap_event->prot = prot;
8391 mmap_event->flags = flags;
8393 if (!(vma->vm_flags & VM_EXEC))
8394 mmap_event->event_id.header.misc |= PERF_RECORD_MISC_MMAP_DATA;
8396 mmap_event->event_id.header.size = sizeof(mmap_event->event_id) + size;
8398 if (atomic_read(&nr_build_id_events))
8399 build_id_parse(vma, mmap_event->build_id, &mmap_event->build_id_size);
8401 perf_iterate_sb(perf_event_mmap_output,
8409 * Check whether inode and address range match filter criteria.
8411 static bool perf_addr_filter_match(struct perf_addr_filter *filter,
8412 struct file *file, unsigned long offset,
8415 /* d_inode(NULL) won't be equal to any mapped user-space file */
8416 if (!filter->path.dentry)
8419 if (d_inode(filter->path.dentry) != file_inode(file))
8422 if (filter->offset > offset + size)
8425 if (filter->offset + filter->size < offset)
8431 static bool perf_addr_filter_vma_adjust(struct perf_addr_filter *filter,
8432 struct vm_area_struct *vma,
8433 struct perf_addr_filter_range *fr)
8435 unsigned long vma_size = vma->vm_end - vma->vm_start;
8436 unsigned long off = vma->vm_pgoff << PAGE_SHIFT;
8437 struct file *file = vma->vm_file;
8439 if (!perf_addr_filter_match(filter, file, off, vma_size))
8442 if (filter->offset < off) {
8443 fr->start = vma->vm_start;
8444 fr->size = min(vma_size, filter->size - (off - filter->offset));
8446 fr->start = vma->vm_start + filter->offset - off;
8447 fr->size = min(vma->vm_end - fr->start, filter->size);
8453 static void __perf_addr_filters_adjust(struct perf_event *event, void *data)
8455 struct perf_addr_filters_head *ifh = perf_event_addr_filters(event);
8456 struct vm_area_struct *vma = data;
8457 struct perf_addr_filter *filter;
8458 unsigned int restart = 0, count = 0;
8459 unsigned long flags;
8461 if (!has_addr_filter(event))
8467 raw_spin_lock_irqsave(&ifh->lock, flags);
8468 list_for_each_entry(filter, &ifh->list, entry) {
8469 if (perf_addr_filter_vma_adjust(filter, vma,
8470 &event->addr_filter_ranges[count]))
8477 event->addr_filters_gen++;
8478 raw_spin_unlock_irqrestore(&ifh->lock, flags);
8481 perf_event_stop(event, 1);
8485 * Adjust all task's events' filters to the new vma
8487 static void perf_addr_filters_adjust(struct vm_area_struct *vma)
8489 struct perf_event_context *ctx;
8493 * Data tracing isn't supported yet and as such there is no need
8494 * to keep track of anything that isn't related to executable code:
8496 if (!(vma->vm_flags & VM_EXEC))
8500 for_each_task_context_nr(ctxn) {
8501 ctx = rcu_dereference(current->perf_event_ctxp[ctxn]);
8505 perf_iterate_ctx(ctx, __perf_addr_filters_adjust, vma, true);
8510 void perf_event_mmap(struct vm_area_struct *vma)
8512 struct perf_mmap_event mmap_event;
8514 if (!atomic_read(&nr_mmap_events))
8517 mmap_event = (struct perf_mmap_event){
8523 .type = PERF_RECORD_MMAP,
8524 .misc = PERF_RECORD_MISC_USER,
8529 .start = vma->vm_start,
8530 .len = vma->vm_end - vma->vm_start,
8531 .pgoff = (u64)vma->vm_pgoff << PAGE_SHIFT,
8533 /* .maj (attr_mmap2 only) */
8534 /* .min (attr_mmap2 only) */
8535 /* .ino (attr_mmap2 only) */
8536 /* .ino_generation (attr_mmap2 only) */
8537 /* .prot (attr_mmap2 only) */
8538 /* .flags (attr_mmap2 only) */
8541 perf_addr_filters_adjust(vma);
8542 perf_event_mmap_event(&mmap_event);
8545 void perf_event_aux_event(struct perf_event *event, unsigned long head,
8546 unsigned long size, u64 flags)
8548 struct perf_output_handle handle;
8549 struct perf_sample_data sample;
8550 struct perf_aux_event {
8551 struct perf_event_header header;
8557 .type = PERF_RECORD_AUX,
8559 .size = sizeof(rec),
8567 perf_event_header__init_id(&rec.header, &sample, event);
8568 ret = perf_output_begin(&handle, &sample, event, rec.header.size);
8573 perf_output_put(&handle, rec);
8574 perf_event__output_id_sample(event, &handle, &sample);
8576 perf_output_end(&handle);
8580 * Lost/dropped samples logging
8582 void perf_log_lost_samples(struct perf_event *event, u64 lost)
8584 struct perf_output_handle handle;
8585 struct perf_sample_data sample;
8589 struct perf_event_header header;
8591 } lost_samples_event = {
8593 .type = PERF_RECORD_LOST_SAMPLES,
8595 .size = sizeof(lost_samples_event),
8600 perf_event_header__init_id(&lost_samples_event.header, &sample, event);
8602 ret = perf_output_begin(&handle, &sample, event,
8603 lost_samples_event.header.size);
8607 perf_output_put(&handle, lost_samples_event);
8608 perf_event__output_id_sample(event, &handle, &sample);
8609 perf_output_end(&handle);
8613 * context_switch tracking
8616 struct perf_switch_event {
8617 struct task_struct *task;
8618 struct task_struct *next_prev;
8621 struct perf_event_header header;
8627 static int perf_event_switch_match(struct perf_event *event)
8629 return event->attr.context_switch;
8632 static void perf_event_switch_output(struct perf_event *event, void *data)
8634 struct perf_switch_event *se = data;
8635 struct perf_output_handle handle;
8636 struct perf_sample_data sample;
8639 if (!perf_event_switch_match(event))
8642 /* Only CPU-wide events are allowed to see next/prev pid/tid */
8643 if (event->ctx->task) {
8644 se->event_id.header.type = PERF_RECORD_SWITCH;
8645 se->event_id.header.size = sizeof(se->event_id.header);
8647 se->event_id.header.type = PERF_RECORD_SWITCH_CPU_WIDE;
8648 se->event_id.header.size = sizeof(se->event_id);
8649 se->event_id.next_prev_pid =
8650 perf_event_pid(event, se->next_prev);
8651 se->event_id.next_prev_tid =
8652 perf_event_tid(event, se->next_prev);
8655 perf_event_header__init_id(&se->event_id.header, &sample, event);
8657 ret = perf_output_begin(&handle, &sample, event, se->event_id.header.size);
8661 if (event->ctx->task)
8662 perf_output_put(&handle, se->event_id.header);
8664 perf_output_put(&handle, se->event_id);
8666 perf_event__output_id_sample(event, &handle, &sample);
8668 perf_output_end(&handle);
8671 static void perf_event_switch(struct task_struct *task,
8672 struct task_struct *next_prev, bool sched_in)
8674 struct perf_switch_event switch_event;
8676 /* N.B. caller checks nr_switch_events != 0 */
8678 switch_event = (struct perf_switch_event){
8680 .next_prev = next_prev,
8684 .misc = sched_in ? 0 : PERF_RECORD_MISC_SWITCH_OUT,
8687 /* .next_prev_pid */
8688 /* .next_prev_tid */
8692 if (!sched_in && task->state == TASK_RUNNING)
8693 switch_event.event_id.header.misc |=
8694 PERF_RECORD_MISC_SWITCH_OUT_PREEMPT;
8696 perf_iterate_sb(perf_event_switch_output,
8702 * IRQ throttle logging
8705 static void perf_log_throttle(struct perf_event *event, int enable)
8707 struct perf_output_handle handle;
8708 struct perf_sample_data sample;
8712 struct perf_event_header header;
8716 } throttle_event = {
8718 .type = PERF_RECORD_THROTTLE,
8720 .size = sizeof(throttle_event),
8722 .time = perf_event_clock(event),
8723 .id = primary_event_id(event),
8724 .stream_id = event->id,
8728 throttle_event.header.type = PERF_RECORD_UNTHROTTLE;
8730 perf_event_header__init_id(&throttle_event.header, &sample, event);
8732 ret = perf_output_begin(&handle, &sample, event,
8733 throttle_event.header.size);
8737 perf_output_put(&handle, throttle_event);
8738 perf_event__output_id_sample(event, &handle, &sample);
8739 perf_output_end(&handle);
8743 * ksymbol register/unregister tracking
8746 struct perf_ksymbol_event {
8750 struct perf_event_header header;
8758 static int perf_event_ksymbol_match(struct perf_event *event)
8760 return event->attr.ksymbol;
8763 static void perf_event_ksymbol_output(struct perf_event *event, void *data)
8765 struct perf_ksymbol_event *ksymbol_event = data;
8766 struct perf_output_handle handle;
8767 struct perf_sample_data sample;
8770 if (!perf_event_ksymbol_match(event))
8773 perf_event_header__init_id(&ksymbol_event->event_id.header,
8775 ret = perf_output_begin(&handle, &sample, event,
8776 ksymbol_event->event_id.header.size);
8780 perf_output_put(&handle, ksymbol_event->event_id);
8781 __output_copy(&handle, ksymbol_event->name, ksymbol_event->name_len);
8782 perf_event__output_id_sample(event, &handle, &sample);
8784 perf_output_end(&handle);
8787 void perf_event_ksymbol(u16 ksym_type, u64 addr, u32 len, bool unregister,
8790 struct perf_ksymbol_event ksymbol_event;
8791 char name[KSYM_NAME_LEN];
8795 if (!atomic_read(&nr_ksymbol_events))
8798 if (ksym_type >= PERF_RECORD_KSYMBOL_TYPE_MAX ||
8799 ksym_type == PERF_RECORD_KSYMBOL_TYPE_UNKNOWN)
8802 strlcpy(name, sym, KSYM_NAME_LEN);
8803 name_len = strlen(name) + 1;
8804 while (!IS_ALIGNED(name_len, sizeof(u64)))
8805 name[name_len++] = '\0';
8806 BUILD_BUG_ON(KSYM_NAME_LEN % sizeof(u64));
8809 flags |= PERF_RECORD_KSYMBOL_FLAGS_UNREGISTER;
8811 ksymbol_event = (struct perf_ksymbol_event){
8813 .name_len = name_len,
8816 .type = PERF_RECORD_KSYMBOL,
8817 .size = sizeof(ksymbol_event.event_id) +
8822 .ksym_type = ksym_type,
8827 perf_iterate_sb(perf_event_ksymbol_output, &ksymbol_event, NULL);
8830 WARN_ONCE(1, "%s: Invalid KSYMBOL type 0x%x\n", __func__, ksym_type);
8834 * bpf program load/unload tracking
8837 struct perf_bpf_event {
8838 struct bpf_prog *prog;
8840 struct perf_event_header header;
8844 u8 tag[BPF_TAG_SIZE];
8848 static int perf_event_bpf_match(struct perf_event *event)
8850 return event->attr.bpf_event;
8853 static void perf_event_bpf_output(struct perf_event *event, void *data)
8855 struct perf_bpf_event *bpf_event = data;
8856 struct perf_output_handle handle;
8857 struct perf_sample_data sample;
8860 if (!perf_event_bpf_match(event))
8863 perf_event_header__init_id(&bpf_event->event_id.header,
8865 ret = perf_output_begin(&handle, data, event,
8866 bpf_event->event_id.header.size);
8870 perf_output_put(&handle, bpf_event->event_id);
8871 perf_event__output_id_sample(event, &handle, &sample);
8873 perf_output_end(&handle);
8876 static void perf_event_bpf_emit_ksymbols(struct bpf_prog *prog,
8877 enum perf_bpf_event_type type)
8879 bool unregister = type == PERF_BPF_EVENT_PROG_UNLOAD;
8882 if (prog->aux->func_cnt == 0) {
8883 perf_event_ksymbol(PERF_RECORD_KSYMBOL_TYPE_BPF,
8884 (u64)(unsigned long)prog->bpf_func,
8885 prog->jited_len, unregister,
8886 prog->aux->ksym.name);
8888 for (i = 0; i < prog->aux->func_cnt; i++) {
8889 struct bpf_prog *subprog = prog->aux->func[i];
8892 PERF_RECORD_KSYMBOL_TYPE_BPF,
8893 (u64)(unsigned long)subprog->bpf_func,
8894 subprog->jited_len, unregister,
8895 prog->aux->ksym.name);
8900 void perf_event_bpf_event(struct bpf_prog *prog,
8901 enum perf_bpf_event_type type,
8904 struct perf_bpf_event bpf_event;
8906 if (type <= PERF_BPF_EVENT_UNKNOWN ||
8907 type >= PERF_BPF_EVENT_MAX)
8911 case PERF_BPF_EVENT_PROG_LOAD:
8912 case PERF_BPF_EVENT_PROG_UNLOAD:
8913 if (atomic_read(&nr_ksymbol_events))
8914 perf_event_bpf_emit_ksymbols(prog, type);
8920 if (!atomic_read(&nr_bpf_events))
8923 bpf_event = (struct perf_bpf_event){
8927 .type = PERF_RECORD_BPF_EVENT,
8928 .size = sizeof(bpf_event.event_id),
8932 .id = prog->aux->id,
8936 BUILD_BUG_ON(BPF_TAG_SIZE % sizeof(u64));
8938 memcpy(bpf_event.event_id.tag, prog->tag, BPF_TAG_SIZE);
8939 perf_iterate_sb(perf_event_bpf_output, &bpf_event, NULL);
8942 struct perf_text_poke_event {
8943 const void *old_bytes;
8944 const void *new_bytes;
8950 struct perf_event_header header;
8956 static int perf_event_text_poke_match(struct perf_event *event)
8958 return event->attr.text_poke;
8961 static void perf_event_text_poke_output(struct perf_event *event, void *data)
8963 struct perf_text_poke_event *text_poke_event = data;
8964 struct perf_output_handle handle;
8965 struct perf_sample_data sample;
8969 if (!perf_event_text_poke_match(event))
8972 perf_event_header__init_id(&text_poke_event->event_id.header, &sample, event);
8974 ret = perf_output_begin(&handle, &sample, event,
8975 text_poke_event->event_id.header.size);
8979 perf_output_put(&handle, text_poke_event->event_id);
8980 perf_output_put(&handle, text_poke_event->old_len);
8981 perf_output_put(&handle, text_poke_event->new_len);
8983 __output_copy(&handle, text_poke_event->old_bytes, text_poke_event->old_len);
8984 __output_copy(&handle, text_poke_event->new_bytes, text_poke_event->new_len);
8986 if (text_poke_event->pad)
8987 __output_copy(&handle, &padding, text_poke_event->pad);
8989 perf_event__output_id_sample(event, &handle, &sample);
8991 perf_output_end(&handle);
8994 void perf_event_text_poke(const void *addr, const void *old_bytes,
8995 size_t old_len, const void *new_bytes, size_t new_len)
8997 struct perf_text_poke_event text_poke_event;
9000 if (!atomic_read(&nr_text_poke_events))
9003 tot = sizeof(text_poke_event.old_len) + old_len;
9004 tot += sizeof(text_poke_event.new_len) + new_len;
9005 pad = ALIGN(tot, sizeof(u64)) - tot;
9007 text_poke_event = (struct perf_text_poke_event){
9008 .old_bytes = old_bytes,
9009 .new_bytes = new_bytes,
9015 .type = PERF_RECORD_TEXT_POKE,
9016 .misc = PERF_RECORD_MISC_KERNEL,
9017 .size = sizeof(text_poke_event.event_id) + tot + pad,
9019 .addr = (unsigned long)addr,
9023 perf_iterate_sb(perf_event_text_poke_output, &text_poke_event, NULL);
9026 void perf_event_itrace_started(struct perf_event *event)
9028 event->attach_state |= PERF_ATTACH_ITRACE;
9031 static void perf_log_itrace_start(struct perf_event *event)
9033 struct perf_output_handle handle;
9034 struct perf_sample_data sample;
9035 struct perf_aux_event {
9036 struct perf_event_header header;
9043 event = event->parent;
9045 if (!(event->pmu->capabilities & PERF_PMU_CAP_ITRACE) ||
9046 event->attach_state & PERF_ATTACH_ITRACE)
9049 rec.header.type = PERF_RECORD_ITRACE_START;
9050 rec.header.misc = 0;
9051 rec.header.size = sizeof(rec);
9052 rec.pid = perf_event_pid(event, current);
9053 rec.tid = perf_event_tid(event, current);
9055 perf_event_header__init_id(&rec.header, &sample, event);
9056 ret = perf_output_begin(&handle, &sample, event, rec.header.size);
9061 perf_output_put(&handle, rec);
9062 perf_event__output_id_sample(event, &handle, &sample);
9064 perf_output_end(&handle);
9068 __perf_event_account_interrupt(struct perf_event *event, int throttle)
9070 struct hw_perf_event *hwc = &event->hw;
9074 seq = __this_cpu_read(perf_throttled_seq);
9075 if (seq != hwc->interrupts_seq) {
9076 hwc->interrupts_seq = seq;
9077 hwc->interrupts = 1;
9080 if (unlikely(throttle
9081 && hwc->interrupts >= max_samples_per_tick)) {
9082 __this_cpu_inc(perf_throttled_count);
9083 tick_dep_set_cpu(smp_processor_id(), TICK_DEP_BIT_PERF_EVENTS);
9084 hwc->interrupts = MAX_INTERRUPTS;
9085 perf_log_throttle(event, 0);
9090 if (event->attr.freq) {
9091 u64 now = perf_clock();
9092 s64 delta = now - hwc->freq_time_stamp;
9094 hwc->freq_time_stamp = now;
9096 if (delta > 0 && delta < 2*TICK_NSEC)
9097 perf_adjust_period(event, delta, hwc->last_period, true);
9103 int perf_event_account_interrupt(struct perf_event *event)
9105 return __perf_event_account_interrupt(event, 1);
9109 * Generic event overflow handling, sampling.
9112 static int __perf_event_overflow(struct perf_event *event,
9113 int throttle, struct perf_sample_data *data,
9114 struct pt_regs *regs)
9116 int events = atomic_read(&event->event_limit);
9120 * Non-sampling counters might still use the PMI to fold short
9121 * hardware counters, ignore those.
9123 if (unlikely(!is_sampling_event(event)))
9126 ret = __perf_event_account_interrupt(event, throttle);
9129 * XXX event_limit might not quite work as expected on inherited
9133 event->pending_kill = POLL_IN;
9134 if (events && atomic_dec_and_test(&event->event_limit)) {
9136 event->pending_kill = POLL_HUP;
9137 event->pending_addr = data->addr;
9139 perf_event_disable_inatomic(event);
9142 READ_ONCE(event->overflow_handler)(event, data, regs);
9144 if (*perf_event_fasync(event) && event->pending_kill) {
9145 event->pending_wakeup = 1;
9146 irq_work_queue(&event->pending);
9152 int perf_event_overflow(struct perf_event *event,
9153 struct perf_sample_data *data,
9154 struct pt_regs *regs)
9156 return __perf_event_overflow(event, 1, data, regs);
9160 * Generic software event infrastructure
9163 struct swevent_htable {
9164 struct swevent_hlist *swevent_hlist;
9165 struct mutex hlist_mutex;
9168 /* Recursion avoidance in each contexts */
9169 int recursion[PERF_NR_CONTEXTS];
9172 static DEFINE_PER_CPU(struct swevent_htable, swevent_htable);
9175 * We directly increment event->count and keep a second value in
9176 * event->hw.period_left to count intervals. This period event
9177 * is kept in the range [-sample_period, 0] so that we can use the
9181 u64 perf_swevent_set_period(struct perf_event *event)
9183 struct hw_perf_event *hwc = &event->hw;
9184 u64 period = hwc->last_period;
9188 hwc->last_period = hwc->sample_period;
9191 old = val = local64_read(&hwc->period_left);
9195 nr = div64_u64(period + val, period);
9196 offset = nr * period;
9198 if (local64_cmpxchg(&hwc->period_left, old, val) != old)
9204 static void perf_swevent_overflow(struct perf_event *event, u64 overflow,
9205 struct perf_sample_data *data,
9206 struct pt_regs *regs)
9208 struct hw_perf_event *hwc = &event->hw;
9212 overflow = perf_swevent_set_period(event);
9214 if (hwc->interrupts == MAX_INTERRUPTS)
9217 for (; overflow; overflow--) {
9218 if (__perf_event_overflow(event, throttle,
9221 * We inhibit the overflow from happening when
9222 * hwc->interrupts == MAX_INTERRUPTS.
9230 static void perf_swevent_event(struct perf_event *event, u64 nr,
9231 struct perf_sample_data *data,
9232 struct pt_regs *regs)
9234 struct hw_perf_event *hwc = &event->hw;
9236 local64_add(nr, &event->count);
9241 if (!is_sampling_event(event))
9244 if ((event->attr.sample_type & PERF_SAMPLE_PERIOD) && !event->attr.freq) {
9246 return perf_swevent_overflow(event, 1, data, regs);
9248 data->period = event->hw.last_period;
9250 if (nr == 1 && hwc->sample_period == 1 && !event->attr.freq)
9251 return perf_swevent_overflow(event, 1, data, regs);
9253 if (local64_add_negative(nr, &hwc->period_left))
9256 perf_swevent_overflow(event, 0, data, regs);
9259 static int perf_exclude_event(struct perf_event *event,
9260 struct pt_regs *regs)
9262 if (event->hw.state & PERF_HES_STOPPED)
9266 if (event->attr.exclude_user && user_mode(regs))
9269 if (event->attr.exclude_kernel && !user_mode(regs))
9276 static int perf_swevent_match(struct perf_event *event,
9277 enum perf_type_id type,
9279 struct perf_sample_data *data,
9280 struct pt_regs *regs)
9282 if (event->attr.type != type)
9285 if (event->attr.config != event_id)
9288 if (perf_exclude_event(event, regs))
9294 static inline u64 swevent_hash(u64 type, u32 event_id)
9296 u64 val = event_id | (type << 32);
9298 return hash_64(val, SWEVENT_HLIST_BITS);
9301 static inline struct hlist_head *
9302 __find_swevent_head(struct swevent_hlist *hlist, u64 type, u32 event_id)
9304 u64 hash = swevent_hash(type, event_id);
9306 return &hlist->heads[hash];
9309 /* For the read side: events when they trigger */
9310 static inline struct hlist_head *
9311 find_swevent_head_rcu(struct swevent_htable *swhash, u64 type, u32 event_id)
9313 struct swevent_hlist *hlist;
9315 hlist = rcu_dereference(swhash->swevent_hlist);
9319 return __find_swevent_head(hlist, type, event_id);
9322 /* For the event head insertion and removal in the hlist */
9323 static inline struct hlist_head *
9324 find_swevent_head(struct swevent_htable *swhash, struct perf_event *event)
9326 struct swevent_hlist *hlist;
9327 u32 event_id = event->attr.config;
9328 u64 type = event->attr.type;
9331 * Event scheduling is always serialized against hlist allocation
9332 * and release. Which makes the protected version suitable here.
9333 * The context lock guarantees that.
9335 hlist = rcu_dereference_protected(swhash->swevent_hlist,
9336 lockdep_is_held(&event->ctx->lock));
9340 return __find_swevent_head(hlist, type, event_id);
9343 static void do_perf_sw_event(enum perf_type_id type, u32 event_id,
9345 struct perf_sample_data *data,
9346 struct pt_regs *regs)
9348 struct swevent_htable *swhash = this_cpu_ptr(&swevent_htable);
9349 struct perf_event *event;
9350 struct hlist_head *head;
9353 head = find_swevent_head_rcu(swhash, type, event_id);
9357 hlist_for_each_entry_rcu(event, head, hlist_entry) {
9358 if (perf_swevent_match(event, type, event_id, data, regs))
9359 perf_swevent_event(event, nr, data, regs);
9365 DEFINE_PER_CPU(struct pt_regs, __perf_regs[4]);
9367 int perf_swevent_get_recursion_context(void)
9369 struct swevent_htable *swhash = this_cpu_ptr(&swevent_htable);
9371 return get_recursion_context(swhash->recursion);
9373 EXPORT_SYMBOL_GPL(perf_swevent_get_recursion_context);
9375 void perf_swevent_put_recursion_context(int rctx)
9377 struct swevent_htable *swhash = this_cpu_ptr(&swevent_htable);
9379 put_recursion_context(swhash->recursion, rctx);
9382 void ___perf_sw_event(u32 event_id, u64 nr, struct pt_regs *regs, u64 addr)
9384 struct perf_sample_data data;
9386 if (WARN_ON_ONCE(!regs))
9389 perf_sample_data_init(&data, addr, 0);
9390 do_perf_sw_event(PERF_TYPE_SOFTWARE, event_id, nr, &data, regs);
9393 void __perf_sw_event(u32 event_id, u64 nr, struct pt_regs *regs, u64 addr)
9397 preempt_disable_notrace();
9398 rctx = perf_swevent_get_recursion_context();
9399 if (unlikely(rctx < 0))
9402 ___perf_sw_event(event_id, nr, regs, addr);
9404 perf_swevent_put_recursion_context(rctx);
9406 preempt_enable_notrace();
9409 static void perf_swevent_read(struct perf_event *event)
9413 static int perf_swevent_add(struct perf_event *event, int flags)
9415 struct swevent_htable *swhash = this_cpu_ptr(&swevent_htable);
9416 struct hw_perf_event *hwc = &event->hw;
9417 struct hlist_head *head;
9419 if (is_sampling_event(event)) {
9420 hwc->last_period = hwc->sample_period;
9421 perf_swevent_set_period(event);
9424 hwc->state = !(flags & PERF_EF_START);
9426 head = find_swevent_head(swhash, event);
9427 if (WARN_ON_ONCE(!head))
9430 hlist_add_head_rcu(&event->hlist_entry, head);
9431 perf_event_update_userpage(event);
9436 static void perf_swevent_del(struct perf_event *event, int flags)
9438 hlist_del_rcu(&event->hlist_entry);
9441 static void perf_swevent_start(struct perf_event *event, int flags)
9443 event->hw.state = 0;
9446 static void perf_swevent_stop(struct perf_event *event, int flags)
9448 event->hw.state = PERF_HES_STOPPED;
9451 /* Deref the hlist from the update side */
9452 static inline struct swevent_hlist *
9453 swevent_hlist_deref(struct swevent_htable *swhash)
9455 return rcu_dereference_protected(swhash->swevent_hlist,
9456 lockdep_is_held(&swhash->hlist_mutex));
9459 static void swevent_hlist_release(struct swevent_htable *swhash)
9461 struct swevent_hlist *hlist = swevent_hlist_deref(swhash);
9466 RCU_INIT_POINTER(swhash->swevent_hlist, NULL);
9467 kfree_rcu(hlist, rcu_head);
9470 static void swevent_hlist_put_cpu(int cpu)
9472 struct swevent_htable *swhash = &per_cpu(swevent_htable, cpu);
9474 mutex_lock(&swhash->hlist_mutex);
9476 if (!--swhash->hlist_refcount)
9477 swevent_hlist_release(swhash);
9479 mutex_unlock(&swhash->hlist_mutex);
9482 static void swevent_hlist_put(void)
9486 for_each_possible_cpu(cpu)
9487 swevent_hlist_put_cpu(cpu);
9490 static int swevent_hlist_get_cpu(int cpu)
9492 struct swevent_htable *swhash = &per_cpu(swevent_htable, cpu);
9495 mutex_lock(&swhash->hlist_mutex);
9496 if (!swevent_hlist_deref(swhash) &&
9497 cpumask_test_cpu(cpu, perf_online_mask)) {
9498 struct swevent_hlist *hlist;
9500 hlist = kzalloc(sizeof(*hlist), GFP_KERNEL);
9505 rcu_assign_pointer(swhash->swevent_hlist, hlist);
9507 swhash->hlist_refcount++;
9509 mutex_unlock(&swhash->hlist_mutex);
9514 static int swevent_hlist_get(void)
9516 int err, cpu, failed_cpu;
9518 mutex_lock(&pmus_lock);
9519 for_each_possible_cpu(cpu) {
9520 err = swevent_hlist_get_cpu(cpu);
9526 mutex_unlock(&pmus_lock);
9529 for_each_possible_cpu(cpu) {
9530 if (cpu == failed_cpu)
9532 swevent_hlist_put_cpu(cpu);
9534 mutex_unlock(&pmus_lock);
9538 struct static_key perf_swevent_enabled[PERF_COUNT_SW_MAX];
9540 static void sw_perf_event_destroy(struct perf_event *event)
9542 u64 event_id = event->attr.config;
9544 WARN_ON(event->parent);
9546 static_key_slow_dec(&perf_swevent_enabled[event_id]);
9547 swevent_hlist_put();
9550 static int perf_swevent_init(struct perf_event *event)
9552 u64 event_id = event->attr.config;
9554 if (event->attr.type != PERF_TYPE_SOFTWARE)
9558 * no branch sampling for software events
9560 if (has_branch_stack(event))
9564 case PERF_COUNT_SW_CPU_CLOCK:
9565 case PERF_COUNT_SW_TASK_CLOCK:
9572 if (event_id >= PERF_COUNT_SW_MAX)
9575 if (!event->parent) {
9578 err = swevent_hlist_get();
9582 static_key_slow_inc(&perf_swevent_enabled[event_id]);
9583 event->destroy = sw_perf_event_destroy;
9589 static struct pmu perf_swevent = {
9590 .task_ctx_nr = perf_sw_context,
9592 .capabilities = PERF_PMU_CAP_NO_NMI,
9594 .event_init = perf_swevent_init,
9595 .add = perf_swevent_add,
9596 .del = perf_swevent_del,
9597 .start = perf_swevent_start,
9598 .stop = perf_swevent_stop,
9599 .read = perf_swevent_read,
9602 #ifdef CONFIG_EVENT_TRACING
9604 static int perf_tp_filter_match(struct perf_event *event,
9605 struct perf_sample_data *data)
9607 void *record = data->raw->frag.data;
9609 /* only top level events have filters set */
9611 event = event->parent;
9613 if (likely(!event->filter) || filter_match_preds(event->filter, record))
9618 static int perf_tp_event_match(struct perf_event *event,
9619 struct perf_sample_data *data,
9620 struct pt_regs *regs)
9622 if (event->hw.state & PERF_HES_STOPPED)
9625 * If exclude_kernel, only trace user-space tracepoints (uprobes)
9627 if (event->attr.exclude_kernel && !user_mode(regs))
9630 if (!perf_tp_filter_match(event, data))
9636 void perf_trace_run_bpf_submit(void *raw_data, int size, int rctx,
9637 struct trace_event_call *call, u64 count,
9638 struct pt_regs *regs, struct hlist_head *head,
9639 struct task_struct *task)
9641 if (bpf_prog_array_valid(call)) {
9642 *(struct pt_regs **)raw_data = regs;
9643 if (!trace_call_bpf(call, raw_data) || hlist_empty(head)) {
9644 perf_swevent_put_recursion_context(rctx);
9648 perf_tp_event(call->event.type, count, raw_data, size, regs, head,
9651 EXPORT_SYMBOL_GPL(perf_trace_run_bpf_submit);
9653 void perf_tp_event(u16 event_type, u64 count, void *record, int entry_size,
9654 struct pt_regs *regs, struct hlist_head *head, int rctx,
9655 struct task_struct *task)
9657 struct perf_sample_data data;
9658 struct perf_event *event;
9660 struct perf_raw_record raw = {
9667 perf_sample_data_init(&data, 0, 0);
9670 perf_trace_buf_update(record, event_type);
9672 hlist_for_each_entry_rcu(event, head, hlist_entry) {
9673 if (perf_tp_event_match(event, &data, regs))
9674 perf_swevent_event(event, count, &data, regs);
9678 * If we got specified a target task, also iterate its context and
9679 * deliver this event there too.
9681 if (task && task != current) {
9682 struct perf_event_context *ctx;
9683 struct trace_entry *entry = record;
9686 ctx = rcu_dereference(task->perf_event_ctxp[perf_sw_context]);
9690 list_for_each_entry_rcu(event, &ctx->event_list, event_entry) {
9691 if (event->cpu != smp_processor_id())
9693 if (event->attr.type != PERF_TYPE_TRACEPOINT)
9695 if (event->attr.config != entry->type)
9697 if (perf_tp_event_match(event, &data, regs))
9698 perf_swevent_event(event, count, &data, regs);
9704 perf_swevent_put_recursion_context(rctx);
9706 EXPORT_SYMBOL_GPL(perf_tp_event);
9708 static void tp_perf_event_destroy(struct perf_event *event)
9710 perf_trace_destroy(event);
9713 static int perf_tp_event_init(struct perf_event *event)
9717 if (event->attr.type != PERF_TYPE_TRACEPOINT)
9721 * no branch sampling for tracepoint events
9723 if (has_branch_stack(event))
9726 err = perf_trace_init(event);
9730 event->destroy = tp_perf_event_destroy;
9735 static struct pmu perf_tracepoint = {
9736 .task_ctx_nr = perf_sw_context,
9738 .event_init = perf_tp_event_init,
9739 .add = perf_trace_add,
9740 .del = perf_trace_del,
9741 .start = perf_swevent_start,
9742 .stop = perf_swevent_stop,
9743 .read = perf_swevent_read,
9746 #if defined(CONFIG_KPROBE_EVENTS) || defined(CONFIG_UPROBE_EVENTS)
9748 * Flags in config, used by dynamic PMU kprobe and uprobe
9749 * The flags should match following PMU_FORMAT_ATTR().
9751 * PERF_PROBE_CONFIG_IS_RETPROBE if set, create kretprobe/uretprobe
9752 * if not set, create kprobe/uprobe
9754 * The following values specify a reference counter (or semaphore in the
9755 * terminology of tools like dtrace, systemtap, etc.) Userspace Statically
9756 * Defined Tracepoints (USDT). Currently, we use 40 bit for the offset.
9758 * PERF_UPROBE_REF_CTR_OFFSET_BITS # of bits in config as th offset
9759 * PERF_UPROBE_REF_CTR_OFFSET_SHIFT # of bits to shift left
9761 enum perf_probe_config {
9762 PERF_PROBE_CONFIG_IS_RETPROBE = 1U << 0, /* [k,u]retprobe */
9763 PERF_UPROBE_REF_CTR_OFFSET_BITS = 32,
9764 PERF_UPROBE_REF_CTR_OFFSET_SHIFT = 64 - PERF_UPROBE_REF_CTR_OFFSET_BITS,
9767 PMU_FORMAT_ATTR(retprobe, "config:0");
9770 #ifdef CONFIG_KPROBE_EVENTS
9771 static struct attribute *kprobe_attrs[] = {
9772 &format_attr_retprobe.attr,
9776 static struct attribute_group kprobe_format_group = {
9778 .attrs = kprobe_attrs,
9781 static const struct attribute_group *kprobe_attr_groups[] = {
9782 &kprobe_format_group,
9786 static int perf_kprobe_event_init(struct perf_event *event);
9787 static struct pmu perf_kprobe = {
9788 .task_ctx_nr = perf_sw_context,
9789 .event_init = perf_kprobe_event_init,
9790 .add = perf_trace_add,
9791 .del = perf_trace_del,
9792 .start = perf_swevent_start,
9793 .stop = perf_swevent_stop,
9794 .read = perf_swevent_read,
9795 .attr_groups = kprobe_attr_groups,
9798 static int perf_kprobe_event_init(struct perf_event *event)
9803 if (event->attr.type != perf_kprobe.type)
9806 if (!perfmon_capable())
9810 * no branch sampling for probe events
9812 if (has_branch_stack(event))
9815 is_retprobe = event->attr.config & PERF_PROBE_CONFIG_IS_RETPROBE;
9816 err = perf_kprobe_init(event, is_retprobe);
9820 event->destroy = perf_kprobe_destroy;
9824 #endif /* CONFIG_KPROBE_EVENTS */
9826 #ifdef CONFIG_UPROBE_EVENTS
9827 PMU_FORMAT_ATTR(ref_ctr_offset, "config:32-63");
9829 static struct attribute *uprobe_attrs[] = {
9830 &format_attr_retprobe.attr,
9831 &format_attr_ref_ctr_offset.attr,
9835 static struct attribute_group uprobe_format_group = {
9837 .attrs = uprobe_attrs,
9840 static const struct attribute_group *uprobe_attr_groups[] = {
9841 &uprobe_format_group,
9845 static int perf_uprobe_event_init(struct perf_event *event);
9846 static struct pmu perf_uprobe = {
9847 .task_ctx_nr = perf_sw_context,
9848 .event_init = perf_uprobe_event_init,
9849 .add = perf_trace_add,
9850 .del = perf_trace_del,
9851 .start = perf_swevent_start,
9852 .stop = perf_swevent_stop,
9853 .read = perf_swevent_read,
9854 .attr_groups = uprobe_attr_groups,
9857 static int perf_uprobe_event_init(struct perf_event *event)
9860 unsigned long ref_ctr_offset;
9863 if (event->attr.type != perf_uprobe.type)
9866 if (!perfmon_capable())
9870 * no branch sampling for probe events
9872 if (has_branch_stack(event))
9875 is_retprobe = event->attr.config & PERF_PROBE_CONFIG_IS_RETPROBE;
9876 ref_ctr_offset = event->attr.config >> PERF_UPROBE_REF_CTR_OFFSET_SHIFT;
9877 err = perf_uprobe_init(event, ref_ctr_offset, is_retprobe);
9881 event->destroy = perf_uprobe_destroy;
9885 #endif /* CONFIG_UPROBE_EVENTS */
9887 static inline void perf_tp_register(void)
9889 perf_pmu_register(&perf_tracepoint, "tracepoint", PERF_TYPE_TRACEPOINT);
9890 #ifdef CONFIG_KPROBE_EVENTS
9891 perf_pmu_register(&perf_kprobe, "kprobe", -1);
9893 #ifdef CONFIG_UPROBE_EVENTS
9894 perf_pmu_register(&perf_uprobe, "uprobe", -1);
9898 static void perf_event_free_filter(struct perf_event *event)
9900 ftrace_profile_free_filter(event);
9903 #ifdef CONFIG_BPF_SYSCALL
9904 static void bpf_overflow_handler(struct perf_event *event,
9905 struct perf_sample_data *data,
9906 struct pt_regs *regs)
9908 struct bpf_perf_event_data_kern ctx = {
9914 ctx.regs = perf_arch_bpf_user_pt_regs(regs);
9915 if (unlikely(__this_cpu_inc_return(bpf_prog_active) != 1))
9918 ret = BPF_PROG_RUN(event->prog, &ctx);
9921 __this_cpu_dec(bpf_prog_active);
9925 event->orig_overflow_handler(event, data, regs);
9928 static int perf_event_set_bpf_handler(struct perf_event *event, u32 prog_fd)
9930 struct bpf_prog *prog;
9932 if (event->overflow_handler_context)
9933 /* hw breakpoint or kernel counter */
9939 prog = bpf_prog_get_type(prog_fd, BPF_PROG_TYPE_PERF_EVENT);
9941 return PTR_ERR(prog);
9943 if (event->attr.precise_ip &&
9944 prog->call_get_stack &&
9945 (!(event->attr.sample_type & __PERF_SAMPLE_CALLCHAIN_EARLY) ||
9946 event->attr.exclude_callchain_kernel ||
9947 event->attr.exclude_callchain_user)) {
9949 * On perf_event with precise_ip, calling bpf_get_stack()
9950 * may trigger unwinder warnings and occasional crashes.
9951 * bpf_get_[stack|stackid] works around this issue by using
9952 * callchain attached to perf_sample_data. If the
9953 * perf_event does not full (kernel and user) callchain
9954 * attached to perf_sample_data, do not allow attaching BPF
9955 * program that calls bpf_get_[stack|stackid].
9962 event->orig_overflow_handler = READ_ONCE(event->overflow_handler);
9963 WRITE_ONCE(event->overflow_handler, bpf_overflow_handler);
9967 static void perf_event_free_bpf_handler(struct perf_event *event)
9969 struct bpf_prog *prog = event->prog;
9974 WRITE_ONCE(event->overflow_handler, event->orig_overflow_handler);
9979 static int perf_event_set_bpf_handler(struct perf_event *event, u32 prog_fd)
9983 static void perf_event_free_bpf_handler(struct perf_event *event)
9989 * returns true if the event is a tracepoint, or a kprobe/upprobe created
9990 * with perf_event_open()
9992 static inline bool perf_event_is_tracing(struct perf_event *event)
9994 if (event->pmu == &perf_tracepoint)
9996 #ifdef CONFIG_KPROBE_EVENTS
9997 if (event->pmu == &perf_kprobe)
10000 #ifdef CONFIG_UPROBE_EVENTS
10001 if (event->pmu == &perf_uprobe)
10007 static int perf_event_set_bpf_prog(struct perf_event *event, u32 prog_fd)
10009 bool is_kprobe, is_tracepoint, is_syscall_tp;
10010 struct bpf_prog *prog;
10013 if (!perf_event_is_tracing(event))
10014 return perf_event_set_bpf_handler(event, prog_fd);
10016 is_kprobe = event->tp_event->flags & TRACE_EVENT_FL_UKPROBE;
10017 is_tracepoint = event->tp_event->flags & TRACE_EVENT_FL_TRACEPOINT;
10018 is_syscall_tp = is_syscall_trace_event(event->tp_event);
10019 if (!is_kprobe && !is_tracepoint && !is_syscall_tp)
10020 /* bpf programs can only be attached to u/kprobe or tracepoint */
10023 prog = bpf_prog_get(prog_fd);
10025 return PTR_ERR(prog);
10027 if ((is_kprobe && prog->type != BPF_PROG_TYPE_KPROBE) ||
10028 (is_tracepoint && prog->type != BPF_PROG_TYPE_TRACEPOINT) ||
10029 (is_syscall_tp && prog->type != BPF_PROG_TYPE_TRACEPOINT)) {
10030 /* valid fd, but invalid bpf program type */
10031 bpf_prog_put(prog);
10035 /* Kprobe override only works for kprobes, not uprobes. */
10036 if (prog->kprobe_override &&
10037 !(event->tp_event->flags & TRACE_EVENT_FL_KPROBE)) {
10038 bpf_prog_put(prog);
10042 if (is_tracepoint || is_syscall_tp) {
10043 int off = trace_event_get_offsets(event->tp_event);
10045 if (prog->aux->max_ctx_offset > off) {
10046 bpf_prog_put(prog);
10051 ret = perf_event_attach_bpf_prog(event, prog);
10053 bpf_prog_put(prog);
10057 static void perf_event_free_bpf_prog(struct perf_event *event)
10059 if (!perf_event_is_tracing(event)) {
10060 perf_event_free_bpf_handler(event);
10063 perf_event_detach_bpf_prog(event);
10068 static inline void perf_tp_register(void)
10072 static void perf_event_free_filter(struct perf_event *event)
10076 static int perf_event_set_bpf_prog(struct perf_event *event, u32 prog_fd)
10081 static void perf_event_free_bpf_prog(struct perf_event *event)
10084 #endif /* CONFIG_EVENT_TRACING */
10086 #ifdef CONFIG_HAVE_HW_BREAKPOINT
10087 void perf_bp_event(struct perf_event *bp, void *data)
10089 struct perf_sample_data sample;
10090 struct pt_regs *regs = data;
10092 perf_sample_data_init(&sample, bp->attr.bp_addr, 0);
10094 if (!bp->hw.state && !perf_exclude_event(bp, regs))
10095 perf_swevent_event(bp, 1, &sample, regs);
10100 * Allocate a new address filter
10102 static struct perf_addr_filter *
10103 perf_addr_filter_new(struct perf_event *event, struct list_head *filters)
10105 int node = cpu_to_node(event->cpu == -1 ? 0 : event->cpu);
10106 struct perf_addr_filter *filter;
10108 filter = kzalloc_node(sizeof(*filter), GFP_KERNEL, node);
10112 INIT_LIST_HEAD(&filter->entry);
10113 list_add_tail(&filter->entry, filters);
10118 static void free_filters_list(struct list_head *filters)
10120 struct perf_addr_filter *filter, *iter;
10122 list_for_each_entry_safe(filter, iter, filters, entry) {
10123 path_put(&filter->path);
10124 list_del(&filter->entry);
10130 * Free existing address filters and optionally install new ones
10132 static void perf_addr_filters_splice(struct perf_event *event,
10133 struct list_head *head)
10135 unsigned long flags;
10138 if (!has_addr_filter(event))
10141 /* don't bother with children, they don't have their own filters */
10145 raw_spin_lock_irqsave(&event->addr_filters.lock, flags);
10147 list_splice_init(&event->addr_filters.list, &list);
10149 list_splice(head, &event->addr_filters.list);
10151 raw_spin_unlock_irqrestore(&event->addr_filters.lock, flags);
10153 free_filters_list(&list);
10157 * Scan through mm's vmas and see if one of them matches the
10158 * @filter; if so, adjust filter's address range.
10159 * Called with mm::mmap_lock down for reading.
10161 static void perf_addr_filter_apply(struct perf_addr_filter *filter,
10162 struct mm_struct *mm,
10163 struct perf_addr_filter_range *fr)
10165 struct vm_area_struct *vma;
10167 for (vma = mm->mmap; vma; vma = vma->vm_next) {
10171 if (perf_addr_filter_vma_adjust(filter, vma, fr))
10177 * Update event's address range filters based on the
10178 * task's existing mappings, if any.
10180 static void perf_event_addr_filters_apply(struct perf_event *event)
10182 struct perf_addr_filters_head *ifh = perf_event_addr_filters(event);
10183 struct task_struct *task = READ_ONCE(event->ctx->task);
10184 struct perf_addr_filter *filter;
10185 struct mm_struct *mm = NULL;
10186 unsigned int count = 0;
10187 unsigned long flags;
10190 * We may observe TASK_TOMBSTONE, which means that the event tear-down
10191 * will stop on the parent's child_mutex that our caller is also holding
10193 if (task == TASK_TOMBSTONE)
10196 if (ifh->nr_file_filters) {
10197 mm = get_task_mm(event->ctx->task);
10201 mmap_read_lock(mm);
10204 raw_spin_lock_irqsave(&ifh->lock, flags);
10205 list_for_each_entry(filter, &ifh->list, entry) {
10206 if (filter->path.dentry) {
10208 * Adjust base offset if the filter is associated to a
10209 * binary that needs to be mapped:
10211 event->addr_filter_ranges[count].start = 0;
10212 event->addr_filter_ranges[count].size = 0;
10214 perf_addr_filter_apply(filter, mm, &event->addr_filter_ranges[count]);
10216 event->addr_filter_ranges[count].start = filter->offset;
10217 event->addr_filter_ranges[count].size = filter->size;
10223 event->addr_filters_gen++;
10224 raw_spin_unlock_irqrestore(&ifh->lock, flags);
10226 if (ifh->nr_file_filters) {
10227 mmap_read_unlock(mm);
10233 perf_event_stop(event, 1);
10237 * Address range filtering: limiting the data to certain
10238 * instruction address ranges. Filters are ioctl()ed to us from
10239 * userspace as ascii strings.
10241 * Filter string format:
10243 * ACTION RANGE_SPEC
10244 * where ACTION is one of the
10245 * * "filter": limit the trace to this region
10246 * * "start": start tracing from this address
10247 * * "stop": stop tracing at this address/region;
10249 * * for kernel addresses: <start address>[/<size>]
10250 * * for object files: <start address>[/<size>]@</path/to/object/file>
10252 * if <size> is not specified or is zero, the range is treated as a single
10253 * address; not valid for ACTION=="filter".
10267 IF_STATE_ACTION = 0,
10272 static const match_table_t if_tokens = {
10273 { IF_ACT_FILTER, "filter" },
10274 { IF_ACT_START, "start" },
10275 { IF_ACT_STOP, "stop" },
10276 { IF_SRC_FILE, "%u/%u@%s" },
10277 { IF_SRC_KERNEL, "%u/%u" },
10278 { IF_SRC_FILEADDR, "%u@%s" },
10279 { IF_SRC_KERNELADDR, "%u" },
10280 { IF_ACT_NONE, NULL },
10284 * Address filter string parser
10287 perf_event_parse_addr_filter(struct perf_event *event, char *fstr,
10288 struct list_head *filters)
10290 struct perf_addr_filter *filter = NULL;
10291 char *start, *orig, *filename = NULL;
10292 substring_t args[MAX_OPT_ARGS];
10293 int state = IF_STATE_ACTION, token;
10294 unsigned int kernel = 0;
10297 orig = fstr = kstrdup(fstr, GFP_KERNEL);
10301 while ((start = strsep(&fstr, " ,\n")) != NULL) {
10302 static const enum perf_addr_filter_action_t actions[] = {
10303 [IF_ACT_FILTER] = PERF_ADDR_FILTER_ACTION_FILTER,
10304 [IF_ACT_START] = PERF_ADDR_FILTER_ACTION_START,
10305 [IF_ACT_STOP] = PERF_ADDR_FILTER_ACTION_STOP,
10312 /* filter definition begins */
10313 if (state == IF_STATE_ACTION) {
10314 filter = perf_addr_filter_new(event, filters);
10319 token = match_token(start, if_tokens, args);
10321 case IF_ACT_FILTER:
10324 if (state != IF_STATE_ACTION)
10327 filter->action = actions[token];
10328 state = IF_STATE_SOURCE;
10331 case IF_SRC_KERNELADDR:
10332 case IF_SRC_KERNEL:
10336 case IF_SRC_FILEADDR:
10338 if (state != IF_STATE_SOURCE)
10342 ret = kstrtoul(args[0].from, 0, &filter->offset);
10346 if (token == IF_SRC_KERNEL || token == IF_SRC_FILE) {
10348 ret = kstrtoul(args[1].from, 0, &filter->size);
10353 if (token == IF_SRC_FILE || token == IF_SRC_FILEADDR) {
10354 int fpos = token == IF_SRC_FILE ? 2 : 1;
10357 filename = match_strdup(&args[fpos]);
10364 state = IF_STATE_END;
10372 * Filter definition is fully parsed, validate and install it.
10373 * Make sure that it doesn't contradict itself or the event's
10376 if (state == IF_STATE_END) {
10378 if (kernel && event->attr.exclude_kernel)
10382 * ACTION "filter" must have a non-zero length region
10385 if (filter->action == PERF_ADDR_FILTER_ACTION_FILTER &&
10394 * For now, we only support file-based filters
10395 * in per-task events; doing so for CPU-wide
10396 * events requires additional context switching
10397 * trickery, since same object code will be
10398 * mapped at different virtual addresses in
10399 * different processes.
10402 if (!event->ctx->task)
10405 /* look up the path and grab its inode */
10406 ret = kern_path(filename, LOOKUP_FOLLOW,
10412 if (!filter->path.dentry ||
10413 !S_ISREG(d_inode(filter->path.dentry)
10417 event->addr_filters.nr_file_filters++;
10420 /* ready to consume more filters */
10421 state = IF_STATE_ACTION;
10426 if (state != IF_STATE_ACTION)
10436 free_filters_list(filters);
10443 perf_event_set_addr_filter(struct perf_event *event, char *filter_str)
10445 LIST_HEAD(filters);
10449 * Since this is called in perf_ioctl() path, we're already holding
10452 lockdep_assert_held(&event->ctx->mutex);
10454 if (WARN_ON_ONCE(event->parent))
10457 ret = perf_event_parse_addr_filter(event, filter_str, &filters);
10459 goto fail_clear_files;
10461 ret = event->pmu->addr_filters_validate(&filters);
10463 goto fail_free_filters;
10465 /* remove existing filters, if any */
10466 perf_addr_filters_splice(event, &filters);
10468 /* install new filters */
10469 perf_event_for_each_child(event, perf_event_addr_filters_apply);
10474 free_filters_list(&filters);
10477 event->addr_filters.nr_file_filters = 0;
10482 static int perf_event_set_filter(struct perf_event *event, void __user *arg)
10487 filter_str = strndup_user(arg, PAGE_SIZE);
10488 if (IS_ERR(filter_str))
10489 return PTR_ERR(filter_str);
10491 #ifdef CONFIG_EVENT_TRACING
10492 if (perf_event_is_tracing(event)) {
10493 struct perf_event_context *ctx = event->ctx;
10496 * Beware, here be dragons!!
10498 * the tracepoint muck will deadlock against ctx->mutex, but
10499 * the tracepoint stuff does not actually need it. So
10500 * temporarily drop ctx->mutex. As per perf_event_ctx_lock() we
10501 * already have a reference on ctx.
10503 * This can result in event getting moved to a different ctx,
10504 * but that does not affect the tracepoint state.
10506 mutex_unlock(&ctx->mutex);
10507 ret = ftrace_profile_set_filter(event, event->attr.config, filter_str);
10508 mutex_lock(&ctx->mutex);
10511 if (has_addr_filter(event))
10512 ret = perf_event_set_addr_filter(event, filter_str);
10519 * hrtimer based swevent callback
10522 static enum hrtimer_restart perf_swevent_hrtimer(struct hrtimer *hrtimer)
10524 enum hrtimer_restart ret = HRTIMER_RESTART;
10525 struct perf_sample_data data;
10526 struct pt_regs *regs;
10527 struct perf_event *event;
10530 event = container_of(hrtimer, struct perf_event, hw.hrtimer);
10532 if (event->state != PERF_EVENT_STATE_ACTIVE)
10533 return HRTIMER_NORESTART;
10535 event->pmu->read(event);
10537 perf_sample_data_init(&data, 0, event->hw.last_period);
10538 regs = get_irq_regs();
10540 if (regs && !perf_exclude_event(event, regs)) {
10541 if (!(event->attr.exclude_idle && is_idle_task(current)))
10542 if (__perf_event_overflow(event, 1, &data, regs))
10543 ret = HRTIMER_NORESTART;
10546 period = max_t(u64, 10000, event->hw.sample_period);
10547 hrtimer_forward_now(hrtimer, ns_to_ktime(period));
10552 static void perf_swevent_start_hrtimer(struct perf_event *event)
10554 struct hw_perf_event *hwc = &event->hw;
10557 if (!is_sampling_event(event))
10560 period = local64_read(&hwc->period_left);
10565 local64_set(&hwc->period_left, 0);
10567 period = max_t(u64, 10000, hwc->sample_period);
10569 hrtimer_start(&hwc->hrtimer, ns_to_ktime(period),
10570 HRTIMER_MODE_REL_PINNED_HARD);
10573 static void perf_swevent_cancel_hrtimer(struct perf_event *event)
10575 struct hw_perf_event *hwc = &event->hw;
10577 if (is_sampling_event(event)) {
10578 ktime_t remaining = hrtimer_get_remaining(&hwc->hrtimer);
10579 local64_set(&hwc->period_left, ktime_to_ns(remaining));
10581 hrtimer_cancel(&hwc->hrtimer);
10585 static void perf_swevent_init_hrtimer(struct perf_event *event)
10587 struct hw_perf_event *hwc = &event->hw;
10589 if (!is_sampling_event(event))
10592 hrtimer_init(&hwc->hrtimer, CLOCK_MONOTONIC, HRTIMER_MODE_REL_HARD);
10593 hwc->hrtimer.function = perf_swevent_hrtimer;
10596 * Since hrtimers have a fixed rate, we can do a static freq->period
10597 * mapping and avoid the whole period adjust feedback stuff.
10599 if (event->attr.freq) {
10600 long freq = event->attr.sample_freq;
10602 event->attr.sample_period = NSEC_PER_SEC / freq;
10603 hwc->sample_period = event->attr.sample_period;
10604 local64_set(&hwc->period_left, hwc->sample_period);
10605 hwc->last_period = hwc->sample_period;
10606 event->attr.freq = 0;
10611 * Software event: cpu wall time clock
10614 static void cpu_clock_event_update(struct perf_event *event)
10619 now = local_clock();
10620 prev = local64_xchg(&event->hw.prev_count, now);
10621 local64_add(now - prev, &event->count);
10624 static void cpu_clock_event_start(struct perf_event *event, int flags)
10626 local64_set(&event->hw.prev_count, local_clock());
10627 perf_swevent_start_hrtimer(event);
10630 static void cpu_clock_event_stop(struct perf_event *event, int flags)
10632 perf_swevent_cancel_hrtimer(event);
10633 cpu_clock_event_update(event);
10636 static int cpu_clock_event_add(struct perf_event *event, int flags)
10638 if (flags & PERF_EF_START)
10639 cpu_clock_event_start(event, flags);
10640 perf_event_update_userpage(event);
10645 static void cpu_clock_event_del(struct perf_event *event, int flags)
10647 cpu_clock_event_stop(event, flags);
10650 static void cpu_clock_event_read(struct perf_event *event)
10652 cpu_clock_event_update(event);
10655 static int cpu_clock_event_init(struct perf_event *event)
10657 if (event->attr.type != PERF_TYPE_SOFTWARE)
10660 if (event->attr.config != PERF_COUNT_SW_CPU_CLOCK)
10664 * no branch sampling for software events
10666 if (has_branch_stack(event))
10667 return -EOPNOTSUPP;
10669 perf_swevent_init_hrtimer(event);
10674 static struct pmu perf_cpu_clock = {
10675 .task_ctx_nr = perf_sw_context,
10677 .capabilities = PERF_PMU_CAP_NO_NMI,
10679 .event_init = cpu_clock_event_init,
10680 .add = cpu_clock_event_add,
10681 .del = cpu_clock_event_del,
10682 .start = cpu_clock_event_start,
10683 .stop = cpu_clock_event_stop,
10684 .read = cpu_clock_event_read,
10688 * Software event: task time clock
10691 static void task_clock_event_update(struct perf_event *event, u64 now)
10696 prev = local64_xchg(&event->hw.prev_count, now);
10697 delta = now - prev;
10698 local64_add(delta, &event->count);
10701 static void task_clock_event_start(struct perf_event *event, int flags)
10703 local64_set(&event->hw.prev_count, event->ctx->time);
10704 perf_swevent_start_hrtimer(event);
10707 static void task_clock_event_stop(struct perf_event *event, int flags)
10709 perf_swevent_cancel_hrtimer(event);
10710 task_clock_event_update(event, event->ctx->time);
10713 static int task_clock_event_add(struct perf_event *event, int flags)
10715 if (flags & PERF_EF_START)
10716 task_clock_event_start(event, flags);
10717 perf_event_update_userpage(event);
10722 static void task_clock_event_del(struct perf_event *event, int flags)
10724 task_clock_event_stop(event, PERF_EF_UPDATE);
10727 static void task_clock_event_read(struct perf_event *event)
10729 u64 now = perf_clock();
10730 u64 delta = now - event->ctx->timestamp;
10731 u64 time = event->ctx->time + delta;
10733 task_clock_event_update(event, time);
10736 static int task_clock_event_init(struct perf_event *event)
10738 if (event->attr.type != PERF_TYPE_SOFTWARE)
10741 if (event->attr.config != PERF_COUNT_SW_TASK_CLOCK)
10745 * no branch sampling for software events
10747 if (has_branch_stack(event))
10748 return -EOPNOTSUPP;
10750 perf_swevent_init_hrtimer(event);
10755 static struct pmu perf_task_clock = {
10756 .task_ctx_nr = perf_sw_context,
10758 .capabilities = PERF_PMU_CAP_NO_NMI,
10760 .event_init = task_clock_event_init,
10761 .add = task_clock_event_add,
10762 .del = task_clock_event_del,
10763 .start = task_clock_event_start,
10764 .stop = task_clock_event_stop,
10765 .read = task_clock_event_read,
10768 static void perf_pmu_nop_void(struct pmu *pmu)
10772 static void perf_pmu_nop_txn(struct pmu *pmu, unsigned int flags)
10776 static int perf_pmu_nop_int(struct pmu *pmu)
10781 static int perf_event_nop_int(struct perf_event *event, u64 value)
10786 static DEFINE_PER_CPU(unsigned int, nop_txn_flags);
10788 static void perf_pmu_start_txn(struct pmu *pmu, unsigned int flags)
10790 __this_cpu_write(nop_txn_flags, flags);
10792 if (flags & ~PERF_PMU_TXN_ADD)
10795 perf_pmu_disable(pmu);
10798 static int perf_pmu_commit_txn(struct pmu *pmu)
10800 unsigned int flags = __this_cpu_read(nop_txn_flags);
10802 __this_cpu_write(nop_txn_flags, 0);
10804 if (flags & ~PERF_PMU_TXN_ADD)
10807 perf_pmu_enable(pmu);
10811 static void perf_pmu_cancel_txn(struct pmu *pmu)
10813 unsigned int flags = __this_cpu_read(nop_txn_flags);
10815 __this_cpu_write(nop_txn_flags, 0);
10817 if (flags & ~PERF_PMU_TXN_ADD)
10820 perf_pmu_enable(pmu);
10823 static int perf_event_idx_default(struct perf_event *event)
10829 * Ensures all contexts with the same task_ctx_nr have the same
10830 * pmu_cpu_context too.
10832 static struct perf_cpu_context __percpu *find_pmu_context(int ctxn)
10839 list_for_each_entry(pmu, &pmus, entry) {
10840 if (pmu->task_ctx_nr == ctxn)
10841 return pmu->pmu_cpu_context;
10847 static void free_pmu_context(struct pmu *pmu)
10850 * Static contexts such as perf_sw_context have a global lifetime
10851 * and may be shared between different PMUs. Avoid freeing them
10852 * when a single PMU is going away.
10854 if (pmu->task_ctx_nr > perf_invalid_context)
10857 free_percpu(pmu->pmu_cpu_context);
10861 * Let userspace know that this PMU supports address range filtering:
10863 static ssize_t nr_addr_filters_show(struct device *dev,
10864 struct device_attribute *attr,
10867 struct pmu *pmu = dev_get_drvdata(dev);
10869 return snprintf(page, PAGE_SIZE - 1, "%d\n", pmu->nr_addr_filters);
10871 DEVICE_ATTR_RO(nr_addr_filters);
10873 static struct idr pmu_idr;
10876 type_show(struct device *dev, struct device_attribute *attr, char *page)
10878 struct pmu *pmu = dev_get_drvdata(dev);
10880 return snprintf(page, PAGE_SIZE-1, "%d\n", pmu->type);
10882 static DEVICE_ATTR_RO(type);
10885 perf_event_mux_interval_ms_show(struct device *dev,
10886 struct device_attribute *attr,
10889 struct pmu *pmu = dev_get_drvdata(dev);
10891 return snprintf(page, PAGE_SIZE-1, "%d\n", pmu->hrtimer_interval_ms);
10894 static DEFINE_MUTEX(mux_interval_mutex);
10897 perf_event_mux_interval_ms_store(struct device *dev,
10898 struct device_attribute *attr,
10899 const char *buf, size_t count)
10901 struct pmu *pmu = dev_get_drvdata(dev);
10902 int timer, cpu, ret;
10904 ret = kstrtoint(buf, 0, &timer);
10911 /* same value, noting to do */
10912 if (timer == pmu->hrtimer_interval_ms)
10915 mutex_lock(&mux_interval_mutex);
10916 pmu->hrtimer_interval_ms = timer;
10918 /* update all cpuctx for this PMU */
10920 for_each_online_cpu(cpu) {
10921 struct perf_cpu_context *cpuctx;
10922 cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
10923 cpuctx->hrtimer_interval = ns_to_ktime(NSEC_PER_MSEC * timer);
10925 cpu_function_call(cpu,
10926 (remote_function_f)perf_mux_hrtimer_restart, cpuctx);
10928 cpus_read_unlock();
10929 mutex_unlock(&mux_interval_mutex);
10933 static DEVICE_ATTR_RW(perf_event_mux_interval_ms);
10935 static struct attribute *pmu_dev_attrs[] = {
10936 &dev_attr_type.attr,
10937 &dev_attr_perf_event_mux_interval_ms.attr,
10940 ATTRIBUTE_GROUPS(pmu_dev);
10942 static int pmu_bus_running;
10943 static struct bus_type pmu_bus = {
10944 .name = "event_source",
10945 .dev_groups = pmu_dev_groups,
10948 static void pmu_dev_release(struct device *dev)
10953 static int pmu_dev_alloc(struct pmu *pmu)
10957 pmu->dev = kzalloc(sizeof(struct device), GFP_KERNEL);
10961 pmu->dev->groups = pmu->attr_groups;
10962 device_initialize(pmu->dev);
10963 ret = dev_set_name(pmu->dev, "%s", pmu->name);
10967 dev_set_drvdata(pmu->dev, pmu);
10968 pmu->dev->bus = &pmu_bus;
10969 pmu->dev->release = pmu_dev_release;
10970 ret = device_add(pmu->dev);
10974 /* For PMUs with address filters, throw in an extra attribute: */
10975 if (pmu->nr_addr_filters)
10976 ret = device_create_file(pmu->dev, &dev_attr_nr_addr_filters);
10981 if (pmu->attr_update)
10982 ret = sysfs_update_groups(&pmu->dev->kobj, pmu->attr_update);
10991 device_del(pmu->dev);
10994 put_device(pmu->dev);
10998 static struct lock_class_key cpuctx_mutex;
10999 static struct lock_class_key cpuctx_lock;
11001 int perf_pmu_register(struct pmu *pmu, const char *name, int type)
11003 int cpu, ret, max = PERF_TYPE_MAX;
11005 mutex_lock(&pmus_lock);
11007 pmu->pmu_disable_count = alloc_percpu(int);
11008 if (!pmu->pmu_disable_count)
11016 if (type != PERF_TYPE_SOFTWARE) {
11020 ret = idr_alloc(&pmu_idr, pmu, max, 0, GFP_KERNEL);
11024 WARN_ON(type >= 0 && ret != type);
11030 if (pmu_bus_running) {
11031 ret = pmu_dev_alloc(pmu);
11037 if (pmu->task_ctx_nr == perf_hw_context) {
11038 static int hw_context_taken = 0;
11041 * Other than systems with heterogeneous CPUs, it never makes
11042 * sense for two PMUs to share perf_hw_context. PMUs which are
11043 * uncore must use perf_invalid_context.
11045 if (WARN_ON_ONCE(hw_context_taken &&
11046 !(pmu->capabilities & PERF_PMU_CAP_HETEROGENEOUS_CPUS)))
11047 pmu->task_ctx_nr = perf_invalid_context;
11049 hw_context_taken = 1;
11052 pmu->pmu_cpu_context = find_pmu_context(pmu->task_ctx_nr);
11053 if (pmu->pmu_cpu_context)
11054 goto got_cpu_context;
11057 pmu->pmu_cpu_context = alloc_percpu(struct perf_cpu_context);
11058 if (!pmu->pmu_cpu_context)
11061 for_each_possible_cpu(cpu) {
11062 struct perf_cpu_context *cpuctx;
11064 cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
11065 __perf_event_init_context(&cpuctx->ctx);
11066 lockdep_set_class(&cpuctx->ctx.mutex, &cpuctx_mutex);
11067 lockdep_set_class(&cpuctx->ctx.lock, &cpuctx_lock);
11068 cpuctx->ctx.pmu = pmu;
11069 cpuctx->online = cpumask_test_cpu(cpu, perf_online_mask);
11071 __perf_mux_hrtimer_init(cpuctx, cpu);
11073 cpuctx->heap_size = ARRAY_SIZE(cpuctx->heap_default);
11074 cpuctx->heap = cpuctx->heap_default;
11078 if (!pmu->start_txn) {
11079 if (pmu->pmu_enable) {
11081 * If we have pmu_enable/pmu_disable calls, install
11082 * transaction stubs that use that to try and batch
11083 * hardware accesses.
11085 pmu->start_txn = perf_pmu_start_txn;
11086 pmu->commit_txn = perf_pmu_commit_txn;
11087 pmu->cancel_txn = perf_pmu_cancel_txn;
11089 pmu->start_txn = perf_pmu_nop_txn;
11090 pmu->commit_txn = perf_pmu_nop_int;
11091 pmu->cancel_txn = perf_pmu_nop_void;
11095 if (!pmu->pmu_enable) {
11096 pmu->pmu_enable = perf_pmu_nop_void;
11097 pmu->pmu_disable = perf_pmu_nop_void;
11100 if (!pmu->check_period)
11101 pmu->check_period = perf_event_nop_int;
11103 if (!pmu->event_idx)
11104 pmu->event_idx = perf_event_idx_default;
11107 * Ensure the TYPE_SOFTWARE PMUs are at the head of the list,
11108 * since these cannot be in the IDR. This way the linear search
11109 * is fast, provided a valid software event is provided.
11111 if (type == PERF_TYPE_SOFTWARE || !name)
11112 list_add_rcu(&pmu->entry, &pmus);
11114 list_add_tail_rcu(&pmu->entry, &pmus);
11116 atomic_set(&pmu->exclusive_cnt, 0);
11119 mutex_unlock(&pmus_lock);
11124 device_del(pmu->dev);
11125 put_device(pmu->dev);
11128 if (pmu->type != PERF_TYPE_SOFTWARE)
11129 idr_remove(&pmu_idr, pmu->type);
11132 free_percpu(pmu->pmu_disable_count);
11135 EXPORT_SYMBOL_GPL(perf_pmu_register);
11137 void perf_pmu_unregister(struct pmu *pmu)
11139 mutex_lock(&pmus_lock);
11140 list_del_rcu(&pmu->entry);
11143 * We dereference the pmu list under both SRCU and regular RCU, so
11144 * synchronize against both of those.
11146 synchronize_srcu(&pmus_srcu);
11149 free_percpu(pmu->pmu_disable_count);
11150 if (pmu->type != PERF_TYPE_SOFTWARE)
11151 idr_remove(&pmu_idr, pmu->type);
11152 if (pmu_bus_running) {
11153 if (pmu->nr_addr_filters)
11154 device_remove_file(pmu->dev, &dev_attr_nr_addr_filters);
11155 device_del(pmu->dev);
11156 put_device(pmu->dev);
11158 free_pmu_context(pmu);
11159 mutex_unlock(&pmus_lock);
11161 EXPORT_SYMBOL_GPL(perf_pmu_unregister);
11163 static inline bool has_extended_regs(struct perf_event *event)
11165 return (event->attr.sample_regs_user & PERF_REG_EXTENDED_MASK) ||
11166 (event->attr.sample_regs_intr & PERF_REG_EXTENDED_MASK);
11169 static int perf_try_init_event(struct pmu *pmu, struct perf_event *event)
11171 struct perf_event_context *ctx = NULL;
11174 if (!try_module_get(pmu->module))
11178 * A number of pmu->event_init() methods iterate the sibling_list to,
11179 * for example, validate if the group fits on the PMU. Therefore,
11180 * if this is a sibling event, acquire the ctx->mutex to protect
11181 * the sibling_list.
11183 if (event->group_leader != event && pmu->task_ctx_nr != perf_sw_context) {
11185 * This ctx->mutex can nest when we're called through
11186 * inheritance. See the perf_event_ctx_lock_nested() comment.
11188 ctx = perf_event_ctx_lock_nested(event->group_leader,
11189 SINGLE_DEPTH_NESTING);
11194 ret = pmu->event_init(event);
11197 perf_event_ctx_unlock(event->group_leader, ctx);
11200 if (!(pmu->capabilities & PERF_PMU_CAP_EXTENDED_REGS) &&
11201 has_extended_regs(event))
11204 if (pmu->capabilities & PERF_PMU_CAP_NO_EXCLUDE &&
11205 event_has_any_exclude_flag(event))
11208 if (ret && event->destroy)
11209 event->destroy(event);
11213 module_put(pmu->module);
11218 static struct pmu *perf_init_event(struct perf_event *event)
11220 bool extended_type = false;
11221 int idx, type, ret;
11224 idx = srcu_read_lock(&pmus_srcu);
11226 /* Try parent's PMU first: */
11227 if (event->parent && event->parent->pmu) {
11228 pmu = event->parent->pmu;
11229 ret = perf_try_init_event(pmu, event);
11235 * PERF_TYPE_HARDWARE and PERF_TYPE_HW_CACHE
11236 * are often aliases for PERF_TYPE_RAW.
11238 type = event->attr.type;
11239 if (type == PERF_TYPE_HARDWARE || type == PERF_TYPE_HW_CACHE) {
11240 type = event->attr.config >> PERF_PMU_TYPE_SHIFT;
11242 type = PERF_TYPE_RAW;
11244 extended_type = true;
11245 event->attr.config &= PERF_HW_EVENT_MASK;
11251 pmu = idr_find(&pmu_idr, type);
11254 if (event->attr.type != type && type != PERF_TYPE_RAW &&
11255 !(pmu->capabilities & PERF_PMU_CAP_EXTENDED_HW_TYPE))
11258 ret = perf_try_init_event(pmu, event);
11259 if (ret == -ENOENT && event->attr.type != type && !extended_type) {
11260 type = event->attr.type;
11265 pmu = ERR_PTR(ret);
11270 list_for_each_entry_rcu(pmu, &pmus, entry, lockdep_is_held(&pmus_srcu)) {
11271 ret = perf_try_init_event(pmu, event);
11275 if (ret != -ENOENT) {
11276 pmu = ERR_PTR(ret);
11281 pmu = ERR_PTR(-ENOENT);
11283 srcu_read_unlock(&pmus_srcu, idx);
11288 static void attach_sb_event(struct perf_event *event)
11290 struct pmu_event_list *pel = per_cpu_ptr(&pmu_sb_events, event->cpu);
11292 raw_spin_lock(&pel->lock);
11293 list_add_rcu(&event->sb_list, &pel->list);
11294 raw_spin_unlock(&pel->lock);
11298 * We keep a list of all !task (and therefore per-cpu) events
11299 * that need to receive side-band records.
11301 * This avoids having to scan all the various PMU per-cpu contexts
11302 * looking for them.
11304 static void account_pmu_sb_event(struct perf_event *event)
11306 if (is_sb_event(event))
11307 attach_sb_event(event);
11310 static void account_event_cpu(struct perf_event *event, int cpu)
11315 if (is_cgroup_event(event))
11316 atomic_inc(&per_cpu(perf_cgroup_events, cpu));
11319 /* Freq events need the tick to stay alive (see perf_event_task_tick). */
11320 static void account_freq_event_nohz(void)
11322 #ifdef CONFIG_NO_HZ_FULL
11323 /* Lock so we don't race with concurrent unaccount */
11324 spin_lock(&nr_freq_lock);
11325 if (atomic_inc_return(&nr_freq_events) == 1)
11326 tick_nohz_dep_set(TICK_DEP_BIT_PERF_EVENTS);
11327 spin_unlock(&nr_freq_lock);
11331 static void account_freq_event(void)
11333 if (tick_nohz_full_enabled())
11334 account_freq_event_nohz();
11336 atomic_inc(&nr_freq_events);
11340 static void account_event(struct perf_event *event)
11347 if (event->attach_state & (PERF_ATTACH_TASK | PERF_ATTACH_SCHED_CB))
11349 if (event->attr.mmap || event->attr.mmap_data)
11350 atomic_inc(&nr_mmap_events);
11351 if (event->attr.build_id)
11352 atomic_inc(&nr_build_id_events);
11353 if (event->attr.comm)
11354 atomic_inc(&nr_comm_events);
11355 if (event->attr.namespaces)
11356 atomic_inc(&nr_namespaces_events);
11357 if (event->attr.cgroup)
11358 atomic_inc(&nr_cgroup_events);
11359 if (event->attr.task)
11360 atomic_inc(&nr_task_events);
11361 if (event->attr.freq)
11362 account_freq_event();
11363 if (event->attr.context_switch) {
11364 atomic_inc(&nr_switch_events);
11367 if (has_branch_stack(event))
11369 if (is_cgroup_event(event))
11371 if (event->attr.ksymbol)
11372 atomic_inc(&nr_ksymbol_events);
11373 if (event->attr.bpf_event)
11374 atomic_inc(&nr_bpf_events);
11375 if (event->attr.text_poke)
11376 atomic_inc(&nr_text_poke_events);
11380 * We need the mutex here because static_branch_enable()
11381 * must complete *before* the perf_sched_count increment
11384 if (atomic_inc_not_zero(&perf_sched_count))
11387 mutex_lock(&perf_sched_mutex);
11388 if (!atomic_read(&perf_sched_count)) {
11389 static_branch_enable(&perf_sched_events);
11391 * Guarantee that all CPUs observe they key change and
11392 * call the perf scheduling hooks before proceeding to
11393 * install events that need them.
11398 * Now that we have waited for the sync_sched(), allow further
11399 * increments to by-pass the mutex.
11401 atomic_inc(&perf_sched_count);
11402 mutex_unlock(&perf_sched_mutex);
11406 account_event_cpu(event, event->cpu);
11408 account_pmu_sb_event(event);
11412 * Allocate and initialize an event structure
11414 static struct perf_event *
11415 perf_event_alloc(struct perf_event_attr *attr, int cpu,
11416 struct task_struct *task,
11417 struct perf_event *group_leader,
11418 struct perf_event *parent_event,
11419 perf_overflow_handler_t overflow_handler,
11420 void *context, int cgroup_fd)
11423 struct perf_event *event;
11424 struct hw_perf_event *hwc;
11425 long err = -EINVAL;
11428 if ((unsigned)cpu >= nr_cpu_ids) {
11429 if (!task || cpu != -1)
11430 return ERR_PTR(-EINVAL);
11432 if (attr->sigtrap && !task) {
11433 /* Requires a task: avoid signalling random tasks. */
11434 return ERR_PTR(-EINVAL);
11437 node = (cpu >= 0) ? cpu_to_node(cpu) : -1;
11438 event = kmem_cache_alloc_node(perf_event_cache, GFP_KERNEL | __GFP_ZERO,
11441 return ERR_PTR(-ENOMEM);
11444 * Single events are their own group leaders, with an
11445 * empty sibling list:
11448 group_leader = event;
11450 mutex_init(&event->child_mutex);
11451 INIT_LIST_HEAD(&event->child_list);
11453 INIT_LIST_HEAD(&event->event_entry);
11454 INIT_LIST_HEAD(&event->sibling_list);
11455 INIT_LIST_HEAD(&event->active_list);
11456 init_event_group(event);
11457 INIT_LIST_HEAD(&event->rb_entry);
11458 INIT_LIST_HEAD(&event->active_entry);
11459 INIT_LIST_HEAD(&event->addr_filters.list);
11460 INIT_HLIST_NODE(&event->hlist_entry);
11463 init_waitqueue_head(&event->waitq);
11464 event->pending_disable = -1;
11465 init_irq_work(&event->pending, perf_pending_event);
11467 mutex_init(&event->mmap_mutex);
11468 raw_spin_lock_init(&event->addr_filters.lock);
11470 atomic_long_set(&event->refcount, 1);
11472 event->attr = *attr;
11473 event->group_leader = group_leader;
11477 event->parent = parent_event;
11479 event->ns = get_pid_ns(task_active_pid_ns(current));
11480 event->id = atomic64_inc_return(&perf_event_id);
11482 event->state = PERF_EVENT_STATE_INACTIVE;
11484 if (event->attr.sigtrap)
11485 atomic_set(&event->event_limit, 1);
11488 event->attach_state = PERF_ATTACH_TASK;
11490 * XXX pmu::event_init needs to know what task to account to
11491 * and we cannot use the ctx information because we need the
11492 * pmu before we get a ctx.
11494 event->hw.target = get_task_struct(task);
11497 event->clock = &local_clock;
11499 event->clock = parent_event->clock;
11501 if (!overflow_handler && parent_event) {
11502 overflow_handler = parent_event->overflow_handler;
11503 context = parent_event->overflow_handler_context;
11504 #if defined(CONFIG_BPF_SYSCALL) && defined(CONFIG_EVENT_TRACING)
11505 if (overflow_handler == bpf_overflow_handler) {
11506 struct bpf_prog *prog = parent_event->prog;
11508 bpf_prog_inc(prog);
11509 event->prog = prog;
11510 event->orig_overflow_handler =
11511 parent_event->orig_overflow_handler;
11516 if (overflow_handler) {
11517 event->overflow_handler = overflow_handler;
11518 event->overflow_handler_context = context;
11519 } else if (is_write_backward(event)){
11520 event->overflow_handler = perf_event_output_backward;
11521 event->overflow_handler_context = NULL;
11523 event->overflow_handler = perf_event_output_forward;
11524 event->overflow_handler_context = NULL;
11527 perf_event__state_init(event);
11532 hwc->sample_period = attr->sample_period;
11533 if (attr->freq && attr->sample_freq)
11534 hwc->sample_period = 1;
11535 hwc->last_period = hwc->sample_period;
11537 local64_set(&hwc->period_left, hwc->sample_period);
11540 * We currently do not support PERF_SAMPLE_READ on inherited events.
11541 * See perf_output_read().
11543 if (attr->inherit && (attr->sample_type & PERF_SAMPLE_READ))
11546 if (!has_branch_stack(event))
11547 event->attr.branch_sample_type = 0;
11549 pmu = perf_init_event(event);
11551 err = PTR_ERR(pmu);
11556 * Disallow uncore-cgroup events, they don't make sense as the cgroup will
11557 * be different on other CPUs in the uncore mask.
11559 if (pmu->task_ctx_nr == perf_invalid_context && cgroup_fd != -1) {
11564 if (event->attr.aux_output &&
11565 !(pmu->capabilities & PERF_PMU_CAP_AUX_OUTPUT)) {
11570 if (cgroup_fd != -1) {
11571 err = perf_cgroup_connect(cgroup_fd, event, attr, group_leader);
11576 err = exclusive_event_init(event);
11580 if (has_addr_filter(event)) {
11581 event->addr_filter_ranges = kcalloc(pmu->nr_addr_filters,
11582 sizeof(struct perf_addr_filter_range),
11584 if (!event->addr_filter_ranges) {
11590 * Clone the parent's vma offsets: they are valid until exec()
11591 * even if the mm is not shared with the parent.
11593 if (event->parent) {
11594 struct perf_addr_filters_head *ifh = perf_event_addr_filters(event);
11596 raw_spin_lock_irq(&ifh->lock);
11597 memcpy(event->addr_filter_ranges,
11598 event->parent->addr_filter_ranges,
11599 pmu->nr_addr_filters * sizeof(struct perf_addr_filter_range));
11600 raw_spin_unlock_irq(&ifh->lock);
11603 /* force hw sync on the address filters */
11604 event->addr_filters_gen = 1;
11607 if (!event->parent) {
11608 if (event->attr.sample_type & PERF_SAMPLE_CALLCHAIN) {
11609 err = get_callchain_buffers(attr->sample_max_stack);
11611 goto err_addr_filters;
11615 err = security_perf_event_alloc(event);
11617 goto err_callchain_buffer;
11619 /* symmetric to unaccount_event() in _free_event() */
11620 account_event(event);
11624 err_callchain_buffer:
11625 if (!event->parent) {
11626 if (event->attr.sample_type & PERF_SAMPLE_CALLCHAIN)
11627 put_callchain_buffers();
11630 kfree(event->addr_filter_ranges);
11633 exclusive_event_destroy(event);
11636 if (is_cgroup_event(event))
11637 perf_detach_cgroup(event);
11638 if (event->destroy)
11639 event->destroy(event);
11640 module_put(pmu->module);
11643 put_pid_ns(event->ns);
11644 if (event->hw.target)
11645 put_task_struct(event->hw.target);
11646 kmem_cache_free(perf_event_cache, event);
11648 return ERR_PTR(err);
11651 static int perf_copy_attr(struct perf_event_attr __user *uattr,
11652 struct perf_event_attr *attr)
11657 /* Zero the full structure, so that a short copy will be nice. */
11658 memset(attr, 0, sizeof(*attr));
11660 ret = get_user(size, &uattr->size);
11664 /* ABI compatibility quirk: */
11666 size = PERF_ATTR_SIZE_VER0;
11667 if (size < PERF_ATTR_SIZE_VER0 || size > PAGE_SIZE)
11670 ret = copy_struct_from_user(attr, sizeof(*attr), uattr, size);
11679 if (attr->__reserved_1 || attr->__reserved_2 || attr->__reserved_3)
11682 if (attr->sample_type & ~(PERF_SAMPLE_MAX-1))
11685 if (attr->read_format & ~(PERF_FORMAT_MAX-1))
11688 if (attr->sample_type & PERF_SAMPLE_BRANCH_STACK) {
11689 u64 mask = attr->branch_sample_type;
11691 /* only using defined bits */
11692 if (mask & ~(PERF_SAMPLE_BRANCH_MAX-1))
11695 /* at least one branch bit must be set */
11696 if (!(mask & ~PERF_SAMPLE_BRANCH_PLM_ALL))
11699 /* propagate priv level, when not set for branch */
11700 if (!(mask & PERF_SAMPLE_BRANCH_PLM_ALL)) {
11702 /* exclude_kernel checked on syscall entry */
11703 if (!attr->exclude_kernel)
11704 mask |= PERF_SAMPLE_BRANCH_KERNEL;
11706 if (!attr->exclude_user)
11707 mask |= PERF_SAMPLE_BRANCH_USER;
11709 if (!attr->exclude_hv)
11710 mask |= PERF_SAMPLE_BRANCH_HV;
11712 * adjust user setting (for HW filter setup)
11714 attr->branch_sample_type = mask;
11716 /* privileged levels capture (kernel, hv): check permissions */
11717 if (mask & PERF_SAMPLE_BRANCH_PERM_PLM) {
11718 ret = perf_allow_kernel(attr);
11724 if (attr->sample_type & PERF_SAMPLE_REGS_USER) {
11725 ret = perf_reg_validate(attr->sample_regs_user);
11730 if (attr->sample_type & PERF_SAMPLE_STACK_USER) {
11731 if (!arch_perf_have_user_stack_dump())
11735 * We have __u32 type for the size, but so far
11736 * we can only use __u16 as maximum due to the
11737 * __u16 sample size limit.
11739 if (attr->sample_stack_user >= USHRT_MAX)
11741 else if (!IS_ALIGNED(attr->sample_stack_user, sizeof(u64)))
11745 if (!attr->sample_max_stack)
11746 attr->sample_max_stack = sysctl_perf_event_max_stack;
11748 if (attr->sample_type & PERF_SAMPLE_REGS_INTR)
11749 ret = perf_reg_validate(attr->sample_regs_intr);
11751 #ifndef CONFIG_CGROUP_PERF
11752 if (attr->sample_type & PERF_SAMPLE_CGROUP)
11755 if ((attr->sample_type & PERF_SAMPLE_WEIGHT) &&
11756 (attr->sample_type & PERF_SAMPLE_WEIGHT_STRUCT))
11759 if (!attr->inherit && attr->inherit_thread)
11762 if (attr->remove_on_exec && attr->enable_on_exec)
11765 if (attr->sigtrap && !attr->remove_on_exec)
11772 put_user(sizeof(*attr), &uattr->size);
11778 perf_event_set_output(struct perf_event *event, struct perf_event *output_event)
11780 struct perf_buffer *rb = NULL;
11786 /* don't allow circular references */
11787 if (event == output_event)
11791 * Don't allow cross-cpu buffers
11793 if (output_event->cpu != event->cpu)
11797 * If its not a per-cpu rb, it must be the same task.
11799 if (output_event->cpu == -1 && output_event->ctx != event->ctx)
11803 * Mixing clocks in the same buffer is trouble you don't need.
11805 if (output_event->clock != event->clock)
11809 * Either writing ring buffer from beginning or from end.
11810 * Mixing is not allowed.
11812 if (is_write_backward(output_event) != is_write_backward(event))
11816 * If both events generate aux data, they must be on the same PMU
11818 if (has_aux(event) && has_aux(output_event) &&
11819 event->pmu != output_event->pmu)
11823 mutex_lock(&event->mmap_mutex);
11824 /* Can't redirect output if we've got an active mmap() */
11825 if (atomic_read(&event->mmap_count))
11828 if (output_event) {
11829 /* get the rb we want to redirect to */
11830 rb = ring_buffer_get(output_event);
11835 ring_buffer_attach(event, rb);
11839 mutex_unlock(&event->mmap_mutex);
11845 static void mutex_lock_double(struct mutex *a, struct mutex *b)
11851 mutex_lock_nested(b, SINGLE_DEPTH_NESTING);
11854 static int perf_event_set_clock(struct perf_event *event, clockid_t clk_id)
11856 bool nmi_safe = false;
11859 case CLOCK_MONOTONIC:
11860 event->clock = &ktime_get_mono_fast_ns;
11864 case CLOCK_MONOTONIC_RAW:
11865 event->clock = &ktime_get_raw_fast_ns;
11869 case CLOCK_REALTIME:
11870 event->clock = &ktime_get_real_ns;
11873 case CLOCK_BOOTTIME:
11874 event->clock = &ktime_get_boottime_ns;
11878 event->clock = &ktime_get_clocktai_ns;
11885 if (!nmi_safe && !(event->pmu->capabilities & PERF_PMU_CAP_NO_NMI))
11892 * Variation on perf_event_ctx_lock_nested(), except we take two context
11895 static struct perf_event_context *
11896 __perf_event_ctx_lock_double(struct perf_event *group_leader,
11897 struct perf_event_context *ctx)
11899 struct perf_event_context *gctx;
11903 gctx = READ_ONCE(group_leader->ctx);
11904 if (!refcount_inc_not_zero(&gctx->refcount)) {
11910 mutex_lock_double(&gctx->mutex, &ctx->mutex);
11912 if (group_leader->ctx != gctx) {
11913 mutex_unlock(&ctx->mutex);
11914 mutex_unlock(&gctx->mutex);
11923 * sys_perf_event_open - open a performance event, associate it to a task/cpu
11925 * @attr_uptr: event_id type attributes for monitoring/sampling
11928 * @group_fd: group leader event fd
11930 SYSCALL_DEFINE5(perf_event_open,
11931 struct perf_event_attr __user *, attr_uptr,
11932 pid_t, pid, int, cpu, int, group_fd, unsigned long, flags)
11934 struct perf_event *group_leader = NULL, *output_event = NULL;
11935 struct perf_event *event, *sibling;
11936 struct perf_event_attr attr;
11937 struct perf_event_context *ctx, *gctx;
11938 struct file *event_file = NULL;
11939 struct fd group = {NULL, 0};
11940 struct task_struct *task = NULL;
11943 int move_group = 0;
11945 int f_flags = O_RDWR;
11946 int cgroup_fd = -1;
11948 /* for future expandability... */
11949 if (flags & ~PERF_FLAG_ALL)
11952 /* Do we allow access to perf_event_open(2) ? */
11953 err = security_perf_event_open(&attr, PERF_SECURITY_OPEN);
11957 err = perf_copy_attr(attr_uptr, &attr);
11961 if (!attr.exclude_kernel) {
11962 err = perf_allow_kernel(&attr);
11967 if (attr.namespaces) {
11968 if (!perfmon_capable())
11973 if (attr.sample_freq > sysctl_perf_event_sample_rate)
11976 if (attr.sample_period & (1ULL << 63))
11980 /* Only privileged users can get physical addresses */
11981 if ((attr.sample_type & PERF_SAMPLE_PHYS_ADDR)) {
11982 err = perf_allow_kernel(&attr);
11987 /* REGS_INTR can leak data, lockdown must prevent this */
11988 if (attr.sample_type & PERF_SAMPLE_REGS_INTR) {
11989 err = security_locked_down(LOCKDOWN_PERF);
11995 * In cgroup mode, the pid argument is used to pass the fd
11996 * opened to the cgroup directory in cgroupfs. The cpu argument
11997 * designates the cpu on which to monitor threads from that
12000 if ((flags & PERF_FLAG_PID_CGROUP) && (pid == -1 || cpu == -1))
12003 if (flags & PERF_FLAG_FD_CLOEXEC)
12004 f_flags |= O_CLOEXEC;
12006 event_fd = get_unused_fd_flags(f_flags);
12010 if (group_fd != -1) {
12011 err = perf_fget_light(group_fd, &group);
12014 group_leader = group.file->private_data;
12015 if (flags & PERF_FLAG_FD_OUTPUT)
12016 output_event = group_leader;
12017 if (flags & PERF_FLAG_FD_NO_GROUP)
12018 group_leader = NULL;
12021 if (pid != -1 && !(flags & PERF_FLAG_PID_CGROUP)) {
12022 task = find_lively_task_by_vpid(pid);
12023 if (IS_ERR(task)) {
12024 err = PTR_ERR(task);
12029 if (task && group_leader &&
12030 group_leader->attr.inherit != attr.inherit) {
12035 if (flags & PERF_FLAG_PID_CGROUP)
12038 event = perf_event_alloc(&attr, cpu, task, group_leader, NULL,
12039 NULL, NULL, cgroup_fd);
12040 if (IS_ERR(event)) {
12041 err = PTR_ERR(event);
12045 if (is_sampling_event(event)) {
12046 if (event->pmu->capabilities & PERF_PMU_CAP_NO_INTERRUPT) {
12053 * Special case software events and allow them to be part of
12054 * any hardware group.
12058 if (attr.use_clockid) {
12059 err = perf_event_set_clock(event, attr.clockid);
12064 if (pmu->task_ctx_nr == perf_sw_context)
12065 event->event_caps |= PERF_EV_CAP_SOFTWARE;
12067 if (group_leader) {
12068 if (is_software_event(event) &&
12069 !in_software_context(group_leader)) {
12071 * If the event is a sw event, but the group_leader
12072 * is on hw context.
12074 * Allow the addition of software events to hw
12075 * groups, this is safe because software events
12076 * never fail to schedule.
12078 pmu = group_leader->ctx->pmu;
12079 } else if (!is_software_event(event) &&
12080 is_software_event(group_leader) &&
12081 (group_leader->group_caps & PERF_EV_CAP_SOFTWARE)) {
12083 * In case the group is a pure software group, and we
12084 * try to add a hardware event, move the whole group to
12085 * the hardware context.
12092 * Get the target context (task or percpu):
12094 ctx = find_get_context(pmu, task, event);
12096 err = PTR_ERR(ctx);
12101 * Look up the group leader (we will attach this event to it):
12103 if (group_leader) {
12107 * Do not allow a recursive hierarchy (this new sibling
12108 * becoming part of another group-sibling):
12110 if (group_leader->group_leader != group_leader)
12113 /* All events in a group should have the same clock */
12114 if (group_leader->clock != event->clock)
12118 * Make sure we're both events for the same CPU;
12119 * grouping events for different CPUs is broken; since
12120 * you can never concurrently schedule them anyhow.
12122 if (group_leader->cpu != event->cpu)
12126 * Make sure we're both on the same task, or both
12129 if (group_leader->ctx->task != ctx->task)
12133 * Do not allow to attach to a group in a different task
12134 * or CPU context. If we're moving SW events, we'll fix
12135 * this up later, so allow that.
12137 if (!move_group && group_leader->ctx != ctx)
12141 * Only a group leader can be exclusive or pinned
12143 if (attr.exclusive || attr.pinned)
12147 if (output_event) {
12148 err = perf_event_set_output(event, output_event);
12153 event_file = anon_inode_getfile("[perf_event]", &perf_fops, event,
12155 if (IS_ERR(event_file)) {
12156 err = PTR_ERR(event_file);
12162 unsigned int ptrace_mode = PTRACE_MODE_READ_REALCREDS;
12165 err = down_read_interruptible(&task->signal->exec_update_lock);
12169 is_capable = perfmon_capable();
12170 if (attr.sigtrap) {
12172 * perf_event_attr::sigtrap sends signals to the other
12173 * task. Require the current task to also have
12177 is_capable &= ns_capable(__task_cred(task)->user_ns, CAP_KILL);
12181 * If the required capabilities aren't available, checks
12182 * for ptrace permissions: upgrade to ATTACH, since
12183 * sending signals can effectively change the target
12186 ptrace_mode = PTRACE_MODE_ATTACH_REALCREDS;
12190 * Preserve ptrace permission check for backwards compatibility.
12192 * We must hold exec_update_lock across this and any potential
12193 * perf_install_in_context() call for this new event to
12194 * serialize against exec() altering our credentials (and the
12195 * perf_event_exit_task() that could imply).
12198 if (!is_capable && !ptrace_may_access(task, ptrace_mode))
12203 gctx = __perf_event_ctx_lock_double(group_leader, ctx);
12205 if (gctx->task == TASK_TOMBSTONE) {
12211 * Check if we raced against another sys_perf_event_open() call
12212 * moving the software group underneath us.
12214 if (!(group_leader->group_caps & PERF_EV_CAP_SOFTWARE)) {
12216 * If someone moved the group out from under us, check
12217 * if this new event wound up on the same ctx, if so
12218 * its the regular !move_group case, otherwise fail.
12224 perf_event_ctx_unlock(group_leader, gctx);
12230 * Failure to create exclusive events returns -EBUSY.
12233 if (!exclusive_event_installable(group_leader, ctx))
12236 for_each_sibling_event(sibling, group_leader) {
12237 if (!exclusive_event_installable(sibling, ctx))
12241 mutex_lock(&ctx->mutex);
12244 if (ctx->task == TASK_TOMBSTONE) {
12249 if (!perf_event_validate_size(event)) {
12256 * Check if the @cpu we're creating an event for is online.
12258 * We use the perf_cpu_context::ctx::mutex to serialize against
12259 * the hotplug notifiers. See perf_event_{init,exit}_cpu().
12261 struct perf_cpu_context *cpuctx =
12262 container_of(ctx, struct perf_cpu_context, ctx);
12264 if (!cpuctx->online) {
12270 if (perf_need_aux_event(event) && !perf_get_aux_event(event, group_leader)) {
12276 * Must be under the same ctx::mutex as perf_install_in_context(),
12277 * because we need to serialize with concurrent event creation.
12279 if (!exclusive_event_installable(event, ctx)) {
12284 WARN_ON_ONCE(ctx->parent_ctx);
12287 * This is the point on no return; we cannot fail hereafter. This is
12288 * where we start modifying current state.
12293 * See perf_event_ctx_lock() for comments on the details
12294 * of swizzling perf_event::ctx.
12296 perf_remove_from_context(group_leader, 0);
12299 for_each_sibling_event(sibling, group_leader) {
12300 perf_remove_from_context(sibling, 0);
12305 * Wait for everybody to stop referencing the events through
12306 * the old lists, before installing it on new lists.
12311 * Install the group siblings before the group leader.
12313 * Because a group leader will try and install the entire group
12314 * (through the sibling list, which is still in-tact), we can
12315 * end up with siblings installed in the wrong context.
12317 * By installing siblings first we NO-OP because they're not
12318 * reachable through the group lists.
12320 for_each_sibling_event(sibling, group_leader) {
12321 perf_event__state_init(sibling);
12322 perf_install_in_context(ctx, sibling, sibling->cpu);
12327 * Removing from the context ends up with disabled
12328 * event. What we want here is event in the initial
12329 * startup state, ready to be add into new context.
12331 perf_event__state_init(group_leader);
12332 perf_install_in_context(ctx, group_leader, group_leader->cpu);
12337 * Precalculate sample_data sizes; do while holding ctx::mutex such
12338 * that we're serialized against further additions and before
12339 * perf_install_in_context() which is the point the event is active and
12340 * can use these values.
12342 perf_event__header_size(event);
12343 perf_event__id_header_size(event);
12345 event->owner = current;
12347 perf_install_in_context(ctx, event, event->cpu);
12348 perf_unpin_context(ctx);
12351 perf_event_ctx_unlock(group_leader, gctx);
12352 mutex_unlock(&ctx->mutex);
12355 up_read(&task->signal->exec_update_lock);
12356 put_task_struct(task);
12359 mutex_lock(¤t->perf_event_mutex);
12360 list_add_tail(&event->owner_entry, ¤t->perf_event_list);
12361 mutex_unlock(¤t->perf_event_mutex);
12364 * Drop the reference on the group_event after placing the
12365 * new event on the sibling_list. This ensures destruction
12366 * of the group leader will find the pointer to itself in
12367 * perf_group_detach().
12370 fd_install(event_fd, event_file);
12375 perf_event_ctx_unlock(group_leader, gctx);
12376 mutex_unlock(&ctx->mutex);
12379 up_read(&task->signal->exec_update_lock);
12383 perf_unpin_context(ctx);
12387 * If event_file is set, the fput() above will have called ->release()
12388 * and that will take care of freeing the event.
12394 put_task_struct(task);
12398 put_unused_fd(event_fd);
12403 * perf_event_create_kernel_counter
12405 * @attr: attributes of the counter to create
12406 * @cpu: cpu in which the counter is bound
12407 * @task: task to profile (NULL for percpu)
12409 struct perf_event *
12410 perf_event_create_kernel_counter(struct perf_event_attr *attr, int cpu,
12411 struct task_struct *task,
12412 perf_overflow_handler_t overflow_handler,
12415 struct perf_event_context *ctx;
12416 struct perf_event *event;
12420 * Grouping is not supported for kernel events, neither is 'AUX',
12421 * make sure the caller's intentions are adjusted.
12423 if (attr->aux_output)
12424 return ERR_PTR(-EINVAL);
12426 event = perf_event_alloc(attr, cpu, task, NULL, NULL,
12427 overflow_handler, context, -1);
12428 if (IS_ERR(event)) {
12429 err = PTR_ERR(event);
12433 /* Mark owner so we could distinguish it from user events. */
12434 event->owner = TASK_TOMBSTONE;
12437 * Get the target context (task or percpu):
12439 ctx = find_get_context(event->pmu, task, event);
12441 err = PTR_ERR(ctx);
12445 WARN_ON_ONCE(ctx->parent_ctx);
12446 mutex_lock(&ctx->mutex);
12447 if (ctx->task == TASK_TOMBSTONE) {
12454 * Check if the @cpu we're creating an event for is online.
12456 * We use the perf_cpu_context::ctx::mutex to serialize against
12457 * the hotplug notifiers. See perf_event_{init,exit}_cpu().
12459 struct perf_cpu_context *cpuctx =
12460 container_of(ctx, struct perf_cpu_context, ctx);
12461 if (!cpuctx->online) {
12467 if (!exclusive_event_installable(event, ctx)) {
12472 perf_install_in_context(ctx, event, event->cpu);
12473 perf_unpin_context(ctx);
12474 mutex_unlock(&ctx->mutex);
12479 mutex_unlock(&ctx->mutex);
12480 perf_unpin_context(ctx);
12485 return ERR_PTR(err);
12487 EXPORT_SYMBOL_GPL(perf_event_create_kernel_counter);
12489 void perf_pmu_migrate_context(struct pmu *pmu, int src_cpu, int dst_cpu)
12491 struct perf_event_context *src_ctx;
12492 struct perf_event_context *dst_ctx;
12493 struct perf_event *event, *tmp;
12496 src_ctx = &per_cpu_ptr(pmu->pmu_cpu_context, src_cpu)->ctx;
12497 dst_ctx = &per_cpu_ptr(pmu->pmu_cpu_context, dst_cpu)->ctx;
12500 * See perf_event_ctx_lock() for comments on the details
12501 * of swizzling perf_event::ctx.
12503 mutex_lock_double(&src_ctx->mutex, &dst_ctx->mutex);
12504 list_for_each_entry_safe(event, tmp, &src_ctx->event_list,
12506 perf_remove_from_context(event, 0);
12507 unaccount_event_cpu(event, src_cpu);
12509 list_add(&event->migrate_entry, &events);
12513 * Wait for the events to quiesce before re-instating them.
12518 * Re-instate events in 2 passes.
12520 * Skip over group leaders and only install siblings on this first
12521 * pass, siblings will not get enabled without a leader, however a
12522 * leader will enable its siblings, even if those are still on the old
12525 list_for_each_entry_safe(event, tmp, &events, migrate_entry) {
12526 if (event->group_leader == event)
12529 list_del(&event->migrate_entry);
12530 if (event->state >= PERF_EVENT_STATE_OFF)
12531 event->state = PERF_EVENT_STATE_INACTIVE;
12532 account_event_cpu(event, dst_cpu);
12533 perf_install_in_context(dst_ctx, event, dst_cpu);
12538 * Once all the siblings are setup properly, install the group leaders
12541 list_for_each_entry_safe(event, tmp, &events, migrate_entry) {
12542 list_del(&event->migrate_entry);
12543 if (event->state >= PERF_EVENT_STATE_OFF)
12544 event->state = PERF_EVENT_STATE_INACTIVE;
12545 account_event_cpu(event, dst_cpu);
12546 perf_install_in_context(dst_ctx, event, dst_cpu);
12549 mutex_unlock(&dst_ctx->mutex);
12550 mutex_unlock(&src_ctx->mutex);
12552 EXPORT_SYMBOL_GPL(perf_pmu_migrate_context);
12554 static void sync_child_event(struct perf_event *child_event)
12556 struct perf_event *parent_event = child_event->parent;
12559 if (child_event->attr.inherit_stat) {
12560 struct task_struct *task = child_event->ctx->task;
12562 if (task && task != TASK_TOMBSTONE)
12563 perf_event_read_event(child_event, task);
12566 child_val = perf_event_count(child_event);
12569 * Add back the child's count to the parent's count:
12571 atomic64_add(child_val, &parent_event->child_count);
12572 atomic64_add(child_event->total_time_enabled,
12573 &parent_event->child_total_time_enabled);
12574 atomic64_add(child_event->total_time_running,
12575 &parent_event->child_total_time_running);
12579 perf_event_exit_event(struct perf_event *event, struct perf_event_context *ctx)
12581 struct perf_event *parent_event = event->parent;
12582 unsigned long detach_flags = 0;
12584 if (parent_event) {
12586 * Do not destroy the 'original' grouping; because of the
12587 * context switch optimization the original events could've
12588 * ended up in a random child task.
12590 * If we were to destroy the original group, all group related
12591 * operations would cease to function properly after this
12592 * random child dies.
12594 * Do destroy all inherited groups, we don't care about those
12595 * and being thorough is better.
12597 detach_flags = DETACH_GROUP | DETACH_CHILD;
12598 mutex_lock(&parent_event->child_mutex);
12601 perf_remove_from_context(event, detach_flags);
12603 raw_spin_lock_irq(&ctx->lock);
12604 if (event->state > PERF_EVENT_STATE_EXIT)
12605 perf_event_set_state(event, PERF_EVENT_STATE_EXIT);
12606 raw_spin_unlock_irq(&ctx->lock);
12609 * Child events can be freed.
12611 if (parent_event) {
12612 mutex_unlock(&parent_event->child_mutex);
12614 * Kick perf_poll() for is_event_hup();
12616 perf_event_wakeup(parent_event);
12618 put_event(parent_event);
12623 * Parent events are governed by their filedesc, retain them.
12625 perf_event_wakeup(event);
12628 static void perf_event_exit_task_context(struct task_struct *child, int ctxn)
12630 struct perf_event_context *child_ctx, *clone_ctx = NULL;
12631 struct perf_event *child_event, *next;
12633 WARN_ON_ONCE(child != current);
12635 child_ctx = perf_pin_task_context(child, ctxn);
12640 * In order to reduce the amount of tricky in ctx tear-down, we hold
12641 * ctx::mutex over the entire thing. This serializes against almost
12642 * everything that wants to access the ctx.
12644 * The exception is sys_perf_event_open() /
12645 * perf_event_create_kernel_count() which does find_get_context()
12646 * without ctx::mutex (it cannot because of the move_group double mutex
12647 * lock thing). See the comments in perf_install_in_context().
12649 mutex_lock(&child_ctx->mutex);
12652 * In a single ctx::lock section, de-schedule the events and detach the
12653 * context from the task such that we cannot ever get it scheduled back
12656 raw_spin_lock_irq(&child_ctx->lock);
12657 task_ctx_sched_out(__get_cpu_context(child_ctx), child_ctx, EVENT_ALL);
12660 * Now that the context is inactive, destroy the task <-> ctx relation
12661 * and mark the context dead.
12663 RCU_INIT_POINTER(child->perf_event_ctxp[ctxn], NULL);
12664 put_ctx(child_ctx); /* cannot be last */
12665 WRITE_ONCE(child_ctx->task, TASK_TOMBSTONE);
12666 put_task_struct(current); /* cannot be last */
12668 clone_ctx = unclone_ctx(child_ctx);
12669 raw_spin_unlock_irq(&child_ctx->lock);
12672 put_ctx(clone_ctx);
12675 * Report the task dead after unscheduling the events so that we
12676 * won't get any samples after PERF_RECORD_EXIT. We can however still
12677 * get a few PERF_RECORD_READ events.
12679 perf_event_task(child, child_ctx, 0);
12681 list_for_each_entry_safe(child_event, next, &child_ctx->event_list, event_entry)
12682 perf_event_exit_event(child_event, child_ctx);
12684 mutex_unlock(&child_ctx->mutex);
12686 put_ctx(child_ctx);
12690 * When a child task exits, feed back event values to parent events.
12692 * Can be called with exec_update_lock held when called from
12693 * setup_new_exec().
12695 void perf_event_exit_task(struct task_struct *child)
12697 struct perf_event *event, *tmp;
12700 mutex_lock(&child->perf_event_mutex);
12701 list_for_each_entry_safe(event, tmp, &child->perf_event_list,
12703 list_del_init(&event->owner_entry);
12706 * Ensure the list deletion is visible before we clear
12707 * the owner, closes a race against perf_release() where
12708 * we need to serialize on the owner->perf_event_mutex.
12710 smp_store_release(&event->owner, NULL);
12712 mutex_unlock(&child->perf_event_mutex);
12714 for_each_task_context_nr(ctxn)
12715 perf_event_exit_task_context(child, ctxn);
12718 * The perf_event_exit_task_context calls perf_event_task
12719 * with child's task_ctx, which generates EXIT events for
12720 * child contexts and sets child->perf_event_ctxp[] to NULL.
12721 * At this point we need to send EXIT events to cpu contexts.
12723 perf_event_task(child, NULL, 0);
12726 static void perf_free_event(struct perf_event *event,
12727 struct perf_event_context *ctx)
12729 struct perf_event *parent = event->parent;
12731 if (WARN_ON_ONCE(!parent))
12734 mutex_lock(&parent->child_mutex);
12735 list_del_init(&event->child_list);
12736 mutex_unlock(&parent->child_mutex);
12740 raw_spin_lock_irq(&ctx->lock);
12741 perf_group_detach(event);
12742 list_del_event(event, ctx);
12743 raw_spin_unlock_irq(&ctx->lock);
12748 * Free a context as created by inheritance by perf_event_init_task() below,
12749 * used by fork() in case of fail.
12751 * Even though the task has never lived, the context and events have been
12752 * exposed through the child_list, so we must take care tearing it all down.
12754 void perf_event_free_task(struct task_struct *task)
12756 struct perf_event_context *ctx;
12757 struct perf_event *event, *tmp;
12760 for_each_task_context_nr(ctxn) {
12761 ctx = task->perf_event_ctxp[ctxn];
12765 mutex_lock(&ctx->mutex);
12766 raw_spin_lock_irq(&ctx->lock);
12768 * Destroy the task <-> ctx relation and mark the context dead.
12770 * This is important because even though the task hasn't been
12771 * exposed yet the context has been (through child_list).
12773 RCU_INIT_POINTER(task->perf_event_ctxp[ctxn], NULL);
12774 WRITE_ONCE(ctx->task, TASK_TOMBSTONE);
12775 put_task_struct(task); /* cannot be last */
12776 raw_spin_unlock_irq(&ctx->lock);
12778 list_for_each_entry_safe(event, tmp, &ctx->event_list, event_entry)
12779 perf_free_event(event, ctx);
12781 mutex_unlock(&ctx->mutex);
12784 * perf_event_release_kernel() could've stolen some of our
12785 * child events and still have them on its free_list. In that
12786 * case we must wait for these events to have been freed (in
12787 * particular all their references to this task must've been
12790 * Without this copy_process() will unconditionally free this
12791 * task (irrespective of its reference count) and
12792 * _free_event()'s put_task_struct(event->hw.target) will be a
12795 * Wait for all events to drop their context reference.
12797 wait_var_event(&ctx->refcount, refcount_read(&ctx->refcount) == 1);
12798 put_ctx(ctx); /* must be last */
12802 void perf_event_delayed_put(struct task_struct *task)
12806 for_each_task_context_nr(ctxn)
12807 WARN_ON_ONCE(task->perf_event_ctxp[ctxn]);
12810 struct file *perf_event_get(unsigned int fd)
12812 struct file *file = fget(fd);
12814 return ERR_PTR(-EBADF);
12816 if (file->f_op != &perf_fops) {
12818 return ERR_PTR(-EBADF);
12824 const struct perf_event *perf_get_event(struct file *file)
12826 if (file->f_op != &perf_fops)
12827 return ERR_PTR(-EINVAL);
12829 return file->private_data;
12832 const struct perf_event_attr *perf_event_attrs(struct perf_event *event)
12835 return ERR_PTR(-EINVAL);
12837 return &event->attr;
12841 * Inherit an event from parent task to child task.
12844 * - valid pointer on success
12845 * - NULL for orphaned events
12846 * - IS_ERR() on error
12848 static struct perf_event *
12849 inherit_event(struct perf_event *parent_event,
12850 struct task_struct *parent,
12851 struct perf_event_context *parent_ctx,
12852 struct task_struct *child,
12853 struct perf_event *group_leader,
12854 struct perf_event_context *child_ctx)
12856 enum perf_event_state parent_state = parent_event->state;
12857 struct perf_event *child_event;
12858 unsigned long flags;
12861 * Instead of creating recursive hierarchies of events,
12862 * we link inherited events back to the original parent,
12863 * which has a filp for sure, which we use as the reference
12866 if (parent_event->parent)
12867 parent_event = parent_event->parent;
12869 child_event = perf_event_alloc(&parent_event->attr,
12872 group_leader, parent_event,
12874 if (IS_ERR(child_event))
12875 return child_event;
12878 if ((child_event->attach_state & PERF_ATTACH_TASK_DATA) &&
12879 !child_ctx->task_ctx_data) {
12880 struct pmu *pmu = child_event->pmu;
12882 child_ctx->task_ctx_data = alloc_task_ctx_data(pmu);
12883 if (!child_ctx->task_ctx_data) {
12884 free_event(child_event);
12885 return ERR_PTR(-ENOMEM);
12890 * is_orphaned_event() and list_add_tail(&parent_event->child_list)
12891 * must be under the same lock in order to serialize against
12892 * perf_event_release_kernel(), such that either we must observe
12893 * is_orphaned_event() or they will observe us on the child_list.
12895 mutex_lock(&parent_event->child_mutex);
12896 if (is_orphaned_event(parent_event) ||
12897 !atomic_long_inc_not_zero(&parent_event->refcount)) {
12898 mutex_unlock(&parent_event->child_mutex);
12899 /* task_ctx_data is freed with child_ctx */
12900 free_event(child_event);
12904 get_ctx(child_ctx);
12907 * Make the child state follow the state of the parent event,
12908 * not its attr.disabled bit. We hold the parent's mutex,
12909 * so we won't race with perf_event_{en, dis}able_family.
12911 if (parent_state >= PERF_EVENT_STATE_INACTIVE)
12912 child_event->state = PERF_EVENT_STATE_INACTIVE;
12914 child_event->state = PERF_EVENT_STATE_OFF;
12916 if (parent_event->attr.freq) {
12917 u64 sample_period = parent_event->hw.sample_period;
12918 struct hw_perf_event *hwc = &child_event->hw;
12920 hwc->sample_period = sample_period;
12921 hwc->last_period = sample_period;
12923 local64_set(&hwc->period_left, sample_period);
12926 child_event->ctx = child_ctx;
12927 child_event->overflow_handler = parent_event->overflow_handler;
12928 child_event->overflow_handler_context
12929 = parent_event->overflow_handler_context;
12932 * Precalculate sample_data sizes
12934 perf_event__header_size(child_event);
12935 perf_event__id_header_size(child_event);
12938 * Link it up in the child's context:
12940 raw_spin_lock_irqsave(&child_ctx->lock, flags);
12941 add_event_to_ctx(child_event, child_ctx);
12942 child_event->attach_state |= PERF_ATTACH_CHILD;
12943 raw_spin_unlock_irqrestore(&child_ctx->lock, flags);
12946 * Link this into the parent event's child list
12948 list_add_tail(&child_event->child_list, &parent_event->child_list);
12949 mutex_unlock(&parent_event->child_mutex);
12951 return child_event;
12955 * Inherits an event group.
12957 * This will quietly suppress orphaned events; !inherit_event() is not an error.
12958 * This matches with perf_event_release_kernel() removing all child events.
12964 static int inherit_group(struct perf_event *parent_event,
12965 struct task_struct *parent,
12966 struct perf_event_context *parent_ctx,
12967 struct task_struct *child,
12968 struct perf_event_context *child_ctx)
12970 struct perf_event *leader;
12971 struct perf_event *sub;
12972 struct perf_event *child_ctr;
12974 leader = inherit_event(parent_event, parent, parent_ctx,
12975 child, NULL, child_ctx);
12976 if (IS_ERR(leader))
12977 return PTR_ERR(leader);
12979 * @leader can be NULL here because of is_orphaned_event(). In this
12980 * case inherit_event() will create individual events, similar to what
12981 * perf_group_detach() would do anyway.
12983 for_each_sibling_event(sub, parent_event) {
12984 child_ctr = inherit_event(sub, parent, parent_ctx,
12985 child, leader, child_ctx);
12986 if (IS_ERR(child_ctr))
12987 return PTR_ERR(child_ctr);
12989 if (sub->aux_event == parent_event && child_ctr &&
12990 !perf_get_aux_event(child_ctr, leader))
12997 * Creates the child task context and tries to inherit the event-group.
12999 * Clears @inherited_all on !attr.inherited or error. Note that we'll leave
13000 * inherited_all set when we 'fail' to inherit an orphaned event; this is
13001 * consistent with perf_event_release_kernel() removing all child events.
13008 inherit_task_group(struct perf_event *event, struct task_struct *parent,
13009 struct perf_event_context *parent_ctx,
13010 struct task_struct *child, int ctxn,
13011 u64 clone_flags, int *inherited_all)
13014 struct perf_event_context *child_ctx;
13016 if (!event->attr.inherit ||
13017 (event->attr.inherit_thread && !(clone_flags & CLONE_THREAD)) ||
13018 /* Do not inherit if sigtrap and signal handlers were cleared. */
13019 (event->attr.sigtrap && (clone_flags & CLONE_CLEAR_SIGHAND))) {
13020 *inherited_all = 0;
13024 child_ctx = child->perf_event_ctxp[ctxn];
13027 * This is executed from the parent task context, so
13028 * inherit events that have been marked for cloning.
13029 * First allocate and initialize a context for the
13032 child_ctx = alloc_perf_context(parent_ctx->pmu, child);
13036 child->perf_event_ctxp[ctxn] = child_ctx;
13039 ret = inherit_group(event, parent, parent_ctx,
13043 *inherited_all = 0;
13049 * Initialize the perf_event context in task_struct
13051 static int perf_event_init_context(struct task_struct *child, int ctxn,
13054 struct perf_event_context *child_ctx, *parent_ctx;
13055 struct perf_event_context *cloned_ctx;
13056 struct perf_event *event;
13057 struct task_struct *parent = current;
13058 int inherited_all = 1;
13059 unsigned long flags;
13062 if (likely(!parent->perf_event_ctxp[ctxn]))
13066 * If the parent's context is a clone, pin it so it won't get
13067 * swapped under us.
13069 parent_ctx = perf_pin_task_context(parent, ctxn);
13074 * No need to check if parent_ctx != NULL here; since we saw
13075 * it non-NULL earlier, the only reason for it to become NULL
13076 * is if we exit, and since we're currently in the middle of
13077 * a fork we can't be exiting at the same time.
13081 * Lock the parent list. No need to lock the child - not PID
13082 * hashed yet and not running, so nobody can access it.
13084 mutex_lock(&parent_ctx->mutex);
13087 * We dont have to disable NMIs - we are only looking at
13088 * the list, not manipulating it:
13090 perf_event_groups_for_each(event, &parent_ctx->pinned_groups) {
13091 ret = inherit_task_group(event, parent, parent_ctx,
13092 child, ctxn, clone_flags,
13099 * We can't hold ctx->lock when iterating the ->flexible_group list due
13100 * to allocations, but we need to prevent rotation because
13101 * rotate_ctx() will change the list from interrupt context.
13103 raw_spin_lock_irqsave(&parent_ctx->lock, flags);
13104 parent_ctx->rotate_disable = 1;
13105 raw_spin_unlock_irqrestore(&parent_ctx->lock, flags);
13107 perf_event_groups_for_each(event, &parent_ctx->flexible_groups) {
13108 ret = inherit_task_group(event, parent, parent_ctx,
13109 child, ctxn, clone_flags,
13115 raw_spin_lock_irqsave(&parent_ctx->lock, flags);
13116 parent_ctx->rotate_disable = 0;
13118 child_ctx = child->perf_event_ctxp[ctxn];
13120 if (child_ctx && inherited_all) {
13122 * Mark the child context as a clone of the parent
13123 * context, or of whatever the parent is a clone of.
13125 * Note that if the parent is a clone, the holding of
13126 * parent_ctx->lock avoids it from being uncloned.
13128 cloned_ctx = parent_ctx->parent_ctx;
13130 child_ctx->parent_ctx = cloned_ctx;
13131 child_ctx->parent_gen = parent_ctx->parent_gen;
13133 child_ctx->parent_ctx = parent_ctx;
13134 child_ctx->parent_gen = parent_ctx->generation;
13136 get_ctx(child_ctx->parent_ctx);
13139 raw_spin_unlock_irqrestore(&parent_ctx->lock, flags);
13141 mutex_unlock(&parent_ctx->mutex);
13143 perf_unpin_context(parent_ctx);
13144 put_ctx(parent_ctx);
13150 * Initialize the perf_event context in task_struct
13152 int perf_event_init_task(struct task_struct *child, u64 clone_flags)
13156 memset(child->perf_event_ctxp, 0, sizeof(child->perf_event_ctxp));
13157 mutex_init(&child->perf_event_mutex);
13158 INIT_LIST_HEAD(&child->perf_event_list);
13160 for_each_task_context_nr(ctxn) {
13161 ret = perf_event_init_context(child, ctxn, clone_flags);
13163 perf_event_free_task(child);
13171 static void __init perf_event_init_all_cpus(void)
13173 struct swevent_htable *swhash;
13176 zalloc_cpumask_var(&perf_online_mask, GFP_KERNEL);
13178 for_each_possible_cpu(cpu) {
13179 swhash = &per_cpu(swevent_htable, cpu);
13180 mutex_init(&swhash->hlist_mutex);
13181 INIT_LIST_HEAD(&per_cpu(active_ctx_list, cpu));
13183 INIT_LIST_HEAD(&per_cpu(pmu_sb_events.list, cpu));
13184 raw_spin_lock_init(&per_cpu(pmu_sb_events.lock, cpu));
13186 #ifdef CONFIG_CGROUP_PERF
13187 INIT_LIST_HEAD(&per_cpu(cgrp_cpuctx_list, cpu));
13189 INIT_LIST_HEAD(&per_cpu(sched_cb_list, cpu));
13193 static void perf_swevent_init_cpu(unsigned int cpu)
13195 struct swevent_htable *swhash = &per_cpu(swevent_htable, cpu);
13197 mutex_lock(&swhash->hlist_mutex);
13198 if (swhash->hlist_refcount > 0 && !swevent_hlist_deref(swhash)) {
13199 struct swevent_hlist *hlist;
13201 hlist = kzalloc_node(sizeof(*hlist), GFP_KERNEL, cpu_to_node(cpu));
13203 rcu_assign_pointer(swhash->swevent_hlist, hlist);
13205 mutex_unlock(&swhash->hlist_mutex);
13208 #if defined CONFIG_HOTPLUG_CPU || defined CONFIG_KEXEC_CORE
13209 static void __perf_event_exit_context(void *__info)
13211 struct perf_event_context *ctx = __info;
13212 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
13213 struct perf_event *event;
13215 raw_spin_lock(&ctx->lock);
13216 ctx_sched_out(ctx, cpuctx, EVENT_TIME);
13217 list_for_each_entry(event, &ctx->event_list, event_entry)
13218 __perf_remove_from_context(event, cpuctx, ctx, (void *)DETACH_GROUP);
13219 raw_spin_unlock(&ctx->lock);
13222 static void perf_event_exit_cpu_context(int cpu)
13224 struct perf_cpu_context *cpuctx;
13225 struct perf_event_context *ctx;
13228 mutex_lock(&pmus_lock);
13229 list_for_each_entry(pmu, &pmus, entry) {
13230 cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
13231 ctx = &cpuctx->ctx;
13233 mutex_lock(&ctx->mutex);
13234 smp_call_function_single(cpu, __perf_event_exit_context, ctx, 1);
13235 cpuctx->online = 0;
13236 mutex_unlock(&ctx->mutex);
13238 cpumask_clear_cpu(cpu, perf_online_mask);
13239 mutex_unlock(&pmus_lock);
13243 static void perf_event_exit_cpu_context(int cpu) { }
13247 int perf_event_init_cpu(unsigned int cpu)
13249 struct perf_cpu_context *cpuctx;
13250 struct perf_event_context *ctx;
13253 perf_swevent_init_cpu(cpu);
13255 mutex_lock(&pmus_lock);
13256 cpumask_set_cpu(cpu, perf_online_mask);
13257 list_for_each_entry(pmu, &pmus, entry) {
13258 cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
13259 ctx = &cpuctx->ctx;
13261 mutex_lock(&ctx->mutex);
13262 cpuctx->online = 1;
13263 mutex_unlock(&ctx->mutex);
13265 mutex_unlock(&pmus_lock);
13270 int perf_event_exit_cpu(unsigned int cpu)
13272 perf_event_exit_cpu_context(cpu);
13277 perf_reboot(struct notifier_block *notifier, unsigned long val, void *v)
13281 for_each_online_cpu(cpu)
13282 perf_event_exit_cpu(cpu);
13288 * Run the perf reboot notifier at the very last possible moment so that
13289 * the generic watchdog code runs as long as possible.
13291 static struct notifier_block perf_reboot_notifier = {
13292 .notifier_call = perf_reboot,
13293 .priority = INT_MIN,
13296 void __init perf_event_init(void)
13300 idr_init(&pmu_idr);
13302 perf_event_init_all_cpus();
13303 init_srcu_struct(&pmus_srcu);
13304 perf_pmu_register(&perf_swevent, "software", PERF_TYPE_SOFTWARE);
13305 perf_pmu_register(&perf_cpu_clock, NULL, -1);
13306 perf_pmu_register(&perf_task_clock, NULL, -1);
13307 perf_tp_register();
13308 perf_event_init_cpu(smp_processor_id());
13309 register_reboot_notifier(&perf_reboot_notifier);
13311 ret = init_hw_breakpoint();
13312 WARN(ret, "hw_breakpoint initialization failed with: %d", ret);
13314 perf_event_cache = KMEM_CACHE(perf_event, SLAB_PANIC);
13317 * Build time assertion that we keep the data_head at the intended
13318 * location. IOW, validation we got the __reserved[] size right.
13320 BUILD_BUG_ON((offsetof(struct perf_event_mmap_page, data_head))
13324 ssize_t perf_event_sysfs_show(struct device *dev, struct device_attribute *attr,
13327 struct perf_pmu_events_attr *pmu_attr =
13328 container_of(attr, struct perf_pmu_events_attr, attr);
13330 if (pmu_attr->event_str)
13331 return sprintf(page, "%s\n", pmu_attr->event_str);
13335 EXPORT_SYMBOL_GPL(perf_event_sysfs_show);
13337 static int __init perf_event_sysfs_init(void)
13342 mutex_lock(&pmus_lock);
13344 ret = bus_register(&pmu_bus);
13348 list_for_each_entry(pmu, &pmus, entry) {
13349 if (!pmu->name || pmu->type < 0)
13352 ret = pmu_dev_alloc(pmu);
13353 WARN(ret, "Failed to register pmu: %s, reason %d\n", pmu->name, ret);
13355 pmu_bus_running = 1;
13359 mutex_unlock(&pmus_lock);
13363 device_initcall(perf_event_sysfs_init);
13365 #ifdef CONFIG_CGROUP_PERF
13366 static struct cgroup_subsys_state *
13367 perf_cgroup_css_alloc(struct cgroup_subsys_state *parent_css)
13369 struct perf_cgroup *jc;
13371 jc = kzalloc(sizeof(*jc), GFP_KERNEL);
13373 return ERR_PTR(-ENOMEM);
13375 jc->info = alloc_percpu(struct perf_cgroup_info);
13378 return ERR_PTR(-ENOMEM);
13384 static void perf_cgroup_css_free(struct cgroup_subsys_state *css)
13386 struct perf_cgroup *jc = container_of(css, struct perf_cgroup, css);
13388 free_percpu(jc->info);
13392 static int perf_cgroup_css_online(struct cgroup_subsys_state *css)
13394 perf_event_cgroup(css->cgroup);
13398 static int __perf_cgroup_move(void *info)
13400 struct task_struct *task = info;
13402 perf_cgroup_switch(task, PERF_CGROUP_SWOUT | PERF_CGROUP_SWIN);
13407 static void perf_cgroup_attach(struct cgroup_taskset *tset)
13409 struct task_struct *task;
13410 struct cgroup_subsys_state *css;
13412 cgroup_taskset_for_each(task, css, tset)
13413 task_function_call(task, __perf_cgroup_move, task);
13416 struct cgroup_subsys perf_event_cgrp_subsys = {
13417 .css_alloc = perf_cgroup_css_alloc,
13418 .css_free = perf_cgroup_css_free,
13419 .css_online = perf_cgroup_css_online,
13420 .attach = perf_cgroup_attach,
13422 * Implicitly enable on dfl hierarchy so that perf events can
13423 * always be filtered by cgroup2 path as long as perf_event
13424 * controller is not mounted on a legacy hierarchy.
13426 .implicit_on_dfl = true,
13429 #endif /* CONFIG_CGROUP_PERF */