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;
3824 struct pmu *pmu = ctx->pmu;
3826 cpuctx = __get_cpu_context(ctx);
3827 if (cpuctx->task_ctx == ctx) {
3828 if (cpuctx->sched_cb_usage)
3829 __perf_pmu_sched_task(cpuctx, true);
3833 perf_ctx_lock(cpuctx, ctx);
3835 * We must check ctx->nr_events while holding ctx->lock, such
3836 * that we serialize against perf_install_in_context().
3838 if (!ctx->nr_events)
3841 perf_pmu_disable(pmu);
3843 * We want to keep the following priority order:
3844 * cpu pinned (that don't need to move), task pinned,
3845 * cpu flexible, task flexible.
3847 * However, if task's ctx is not carrying any pinned
3848 * events, no need to flip the cpuctx's events around.
3850 if (!RB_EMPTY_ROOT(&ctx->pinned_groups.tree))
3851 cpu_ctx_sched_out(cpuctx, EVENT_FLEXIBLE);
3852 perf_event_sched_in(cpuctx, ctx, task);
3854 if (cpuctx->sched_cb_usage && pmu->sched_task)
3855 pmu->sched_task(cpuctx->task_ctx, true);
3857 perf_pmu_enable(pmu);
3860 perf_ctx_unlock(cpuctx, ctx);
3864 * Called from scheduler to add the events of the current task
3865 * with interrupts disabled.
3867 * We restore the event value and then enable it.
3869 * This does not protect us against NMI, but enable()
3870 * sets the enabled bit in the control field of event _before_
3871 * accessing the event control register. If a NMI hits, then it will
3872 * keep the event running.
3874 void __perf_event_task_sched_in(struct task_struct *prev,
3875 struct task_struct *task)
3877 struct perf_event_context *ctx;
3881 * If cgroup events exist on this CPU, then we need to check if we have
3882 * to switch in PMU state; cgroup event are system-wide mode only.
3884 * Since cgroup events are CPU events, we must schedule these in before
3885 * we schedule in the task events.
3887 if (atomic_read(this_cpu_ptr(&perf_cgroup_events)))
3888 perf_cgroup_sched_in(prev, task);
3890 for_each_task_context_nr(ctxn) {
3891 ctx = task->perf_event_ctxp[ctxn];
3895 perf_event_context_sched_in(ctx, task);
3898 if (atomic_read(&nr_switch_events))
3899 perf_event_switch(task, prev, true);
3901 if (__this_cpu_read(perf_sched_cb_usages))
3902 perf_pmu_sched_task(prev, task, true);
3905 static u64 perf_calculate_period(struct perf_event *event, u64 nsec, u64 count)
3907 u64 frequency = event->attr.sample_freq;
3908 u64 sec = NSEC_PER_SEC;
3909 u64 divisor, dividend;
3911 int count_fls, nsec_fls, frequency_fls, sec_fls;
3913 count_fls = fls64(count);
3914 nsec_fls = fls64(nsec);
3915 frequency_fls = fls64(frequency);
3919 * We got @count in @nsec, with a target of sample_freq HZ
3920 * the target period becomes:
3923 * period = -------------------
3924 * @nsec * sample_freq
3929 * Reduce accuracy by one bit such that @a and @b converge
3930 * to a similar magnitude.
3932 #define REDUCE_FLS(a, b) \
3934 if (a##_fls > b##_fls) { \
3944 * Reduce accuracy until either term fits in a u64, then proceed with
3945 * the other, so that finally we can do a u64/u64 division.
3947 while (count_fls + sec_fls > 64 && nsec_fls + frequency_fls > 64) {
3948 REDUCE_FLS(nsec, frequency);
3949 REDUCE_FLS(sec, count);
3952 if (count_fls + sec_fls > 64) {
3953 divisor = nsec * frequency;
3955 while (count_fls + sec_fls > 64) {
3956 REDUCE_FLS(count, sec);
3960 dividend = count * sec;
3962 dividend = count * sec;
3964 while (nsec_fls + frequency_fls > 64) {
3965 REDUCE_FLS(nsec, frequency);
3969 divisor = nsec * frequency;
3975 return div64_u64(dividend, divisor);
3978 static DEFINE_PER_CPU(int, perf_throttled_count);
3979 static DEFINE_PER_CPU(u64, perf_throttled_seq);
3981 static void perf_adjust_period(struct perf_event *event, u64 nsec, u64 count, bool disable)
3983 struct hw_perf_event *hwc = &event->hw;
3984 s64 period, sample_period;
3987 period = perf_calculate_period(event, nsec, count);
3989 delta = (s64)(period - hwc->sample_period);
3990 delta = (delta + 7) / 8; /* low pass filter */
3992 sample_period = hwc->sample_period + delta;
3997 hwc->sample_period = sample_period;
3999 if (local64_read(&hwc->period_left) > 8*sample_period) {
4001 event->pmu->stop(event, PERF_EF_UPDATE);
4003 local64_set(&hwc->period_left, 0);
4006 event->pmu->start(event, PERF_EF_RELOAD);
4011 * combine freq adjustment with unthrottling to avoid two passes over the
4012 * events. At the same time, make sure, having freq events does not change
4013 * the rate of unthrottling as that would introduce bias.
4015 static void perf_adjust_freq_unthr_context(struct perf_event_context *ctx,
4018 struct perf_event *event;
4019 struct hw_perf_event *hwc;
4020 u64 now, period = TICK_NSEC;
4024 * only need to iterate over all events iff:
4025 * - context have events in frequency mode (needs freq adjust)
4026 * - there are events to unthrottle on this cpu
4028 if (!(ctx->nr_freq || needs_unthr))
4031 raw_spin_lock(&ctx->lock);
4032 perf_pmu_disable(ctx->pmu);
4034 list_for_each_entry_rcu(event, &ctx->event_list, event_entry) {
4035 if (event->state != PERF_EVENT_STATE_ACTIVE)
4038 if (!event_filter_match(event))
4041 perf_pmu_disable(event->pmu);
4045 if (hwc->interrupts == MAX_INTERRUPTS) {
4046 hwc->interrupts = 0;
4047 perf_log_throttle(event, 1);
4048 event->pmu->start(event, 0);
4051 if (!event->attr.freq || !event->attr.sample_freq)
4055 * stop the event and update event->count
4057 event->pmu->stop(event, PERF_EF_UPDATE);
4059 now = local64_read(&event->count);
4060 delta = now - hwc->freq_count_stamp;
4061 hwc->freq_count_stamp = now;
4065 * reload only if value has changed
4066 * we have stopped the event so tell that
4067 * to perf_adjust_period() to avoid stopping it
4071 perf_adjust_period(event, period, delta, false);
4073 event->pmu->start(event, delta > 0 ? PERF_EF_RELOAD : 0);
4075 perf_pmu_enable(event->pmu);
4078 perf_pmu_enable(ctx->pmu);
4079 raw_spin_unlock(&ctx->lock);
4083 * Move @event to the tail of the @ctx's elegible events.
4085 static void rotate_ctx(struct perf_event_context *ctx, struct perf_event *event)
4088 * Rotate the first entry last of non-pinned groups. Rotation might be
4089 * disabled by the inheritance code.
4091 if (ctx->rotate_disable)
4094 perf_event_groups_delete(&ctx->flexible_groups, event);
4095 perf_event_groups_insert(&ctx->flexible_groups, event);
4098 /* pick an event from the flexible_groups to rotate */
4099 static inline struct perf_event *
4100 ctx_event_to_rotate(struct perf_event_context *ctx)
4102 struct perf_event *event;
4104 /* pick the first active flexible event */
4105 event = list_first_entry_or_null(&ctx->flexible_active,
4106 struct perf_event, active_list);
4108 /* if no active flexible event, pick the first event */
4110 event = rb_entry_safe(rb_first(&ctx->flexible_groups.tree),
4111 typeof(*event), group_node);
4115 * Unconditionally clear rotate_necessary; if ctx_flexible_sched_in()
4116 * finds there are unschedulable events, it will set it again.
4118 ctx->rotate_necessary = 0;
4123 static bool perf_rotate_context(struct perf_cpu_context *cpuctx)
4125 struct perf_event *cpu_event = NULL, *task_event = NULL;
4126 struct perf_event_context *task_ctx = NULL;
4127 int cpu_rotate, task_rotate;
4130 * Since we run this from IRQ context, nobody can install new
4131 * events, thus the event count values are stable.
4134 cpu_rotate = cpuctx->ctx.rotate_necessary;
4135 task_ctx = cpuctx->task_ctx;
4136 task_rotate = task_ctx ? task_ctx->rotate_necessary : 0;
4138 if (!(cpu_rotate || task_rotate))
4141 perf_ctx_lock(cpuctx, cpuctx->task_ctx);
4142 perf_pmu_disable(cpuctx->ctx.pmu);
4145 task_event = ctx_event_to_rotate(task_ctx);
4147 cpu_event = ctx_event_to_rotate(&cpuctx->ctx);
4150 * As per the order given at ctx_resched() first 'pop' task flexible
4151 * and then, if needed CPU flexible.
4153 if (task_event || (task_ctx && cpu_event))
4154 ctx_sched_out(task_ctx, cpuctx, EVENT_FLEXIBLE);
4156 cpu_ctx_sched_out(cpuctx, EVENT_FLEXIBLE);
4159 rotate_ctx(task_ctx, task_event);
4161 rotate_ctx(&cpuctx->ctx, cpu_event);
4163 perf_event_sched_in(cpuctx, task_ctx, current);
4165 perf_pmu_enable(cpuctx->ctx.pmu);
4166 perf_ctx_unlock(cpuctx, cpuctx->task_ctx);
4171 void perf_event_task_tick(void)
4173 struct list_head *head = this_cpu_ptr(&active_ctx_list);
4174 struct perf_event_context *ctx, *tmp;
4177 lockdep_assert_irqs_disabled();
4179 __this_cpu_inc(perf_throttled_seq);
4180 throttled = __this_cpu_xchg(perf_throttled_count, 0);
4181 tick_dep_clear_cpu(smp_processor_id(), TICK_DEP_BIT_PERF_EVENTS);
4183 list_for_each_entry_safe(ctx, tmp, head, active_ctx_list)
4184 perf_adjust_freq_unthr_context(ctx, throttled);
4187 static int event_enable_on_exec(struct perf_event *event,
4188 struct perf_event_context *ctx)
4190 if (!event->attr.enable_on_exec)
4193 event->attr.enable_on_exec = 0;
4194 if (event->state >= PERF_EVENT_STATE_INACTIVE)
4197 perf_event_set_state(event, PERF_EVENT_STATE_INACTIVE);
4203 * Enable all of a task's events that have been marked enable-on-exec.
4204 * This expects task == current.
4206 static void perf_event_enable_on_exec(int ctxn)
4208 struct perf_event_context *ctx, *clone_ctx = NULL;
4209 enum event_type_t event_type = 0;
4210 struct perf_cpu_context *cpuctx;
4211 struct perf_event *event;
4212 unsigned long flags;
4215 local_irq_save(flags);
4216 ctx = current->perf_event_ctxp[ctxn];
4217 if (!ctx || !ctx->nr_events)
4220 cpuctx = __get_cpu_context(ctx);
4221 perf_ctx_lock(cpuctx, ctx);
4222 ctx_sched_out(ctx, cpuctx, EVENT_TIME);
4223 list_for_each_entry(event, &ctx->event_list, event_entry) {
4224 enabled |= event_enable_on_exec(event, ctx);
4225 event_type |= get_event_type(event);
4229 * Unclone and reschedule this context if we enabled any event.
4232 clone_ctx = unclone_ctx(ctx);
4233 ctx_resched(cpuctx, ctx, event_type);
4235 ctx_sched_in(ctx, cpuctx, EVENT_TIME, current);
4237 perf_ctx_unlock(cpuctx, ctx);
4240 local_irq_restore(flags);
4246 static void perf_remove_from_owner(struct perf_event *event);
4247 static void perf_event_exit_event(struct perf_event *event,
4248 struct perf_event_context *ctx);
4251 * Removes all events from the current task that have been marked
4252 * remove-on-exec, and feeds their values back to parent events.
4254 static void perf_event_remove_on_exec(int ctxn)
4256 struct perf_event_context *ctx, *clone_ctx = NULL;
4257 struct perf_event *event, *next;
4258 LIST_HEAD(free_list);
4259 unsigned long flags;
4260 bool modified = false;
4262 ctx = perf_pin_task_context(current, ctxn);
4266 mutex_lock(&ctx->mutex);
4268 if (WARN_ON_ONCE(ctx->task != current))
4271 list_for_each_entry_safe(event, next, &ctx->event_list, event_entry) {
4272 if (!event->attr.remove_on_exec)
4275 if (!is_kernel_event(event))
4276 perf_remove_from_owner(event);
4280 perf_event_exit_event(event, ctx);
4283 raw_spin_lock_irqsave(&ctx->lock, flags);
4285 clone_ctx = unclone_ctx(ctx);
4287 raw_spin_unlock_irqrestore(&ctx->lock, flags);
4290 mutex_unlock(&ctx->mutex);
4297 struct perf_read_data {
4298 struct perf_event *event;
4303 static int __perf_event_read_cpu(struct perf_event *event, int event_cpu)
4305 u16 local_pkg, event_pkg;
4307 if (event->group_caps & PERF_EV_CAP_READ_ACTIVE_PKG) {
4308 int local_cpu = smp_processor_id();
4310 event_pkg = topology_physical_package_id(event_cpu);
4311 local_pkg = topology_physical_package_id(local_cpu);
4313 if (event_pkg == local_pkg)
4321 * Cross CPU call to read the hardware event
4323 static void __perf_event_read(void *info)
4325 struct perf_read_data *data = info;
4326 struct perf_event *sub, *event = data->event;
4327 struct perf_event_context *ctx = event->ctx;
4328 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
4329 struct pmu *pmu = event->pmu;
4332 * If this is a task context, we need to check whether it is
4333 * the current task context of this cpu. If not it has been
4334 * scheduled out before the smp call arrived. In that case
4335 * event->count would have been updated to a recent sample
4336 * when the event was scheduled out.
4338 if (ctx->task && cpuctx->task_ctx != ctx)
4341 raw_spin_lock(&ctx->lock);
4342 if (ctx->is_active & EVENT_TIME) {
4343 update_context_time(ctx);
4344 update_cgrp_time_from_event(event);
4347 perf_event_update_time(event);
4349 perf_event_update_sibling_time(event);
4351 if (event->state != PERF_EVENT_STATE_ACTIVE)
4360 pmu->start_txn(pmu, PERF_PMU_TXN_READ);
4364 for_each_sibling_event(sub, event) {
4365 if (sub->state == PERF_EVENT_STATE_ACTIVE) {
4367 * Use sibling's PMU rather than @event's since
4368 * sibling could be on different (eg: software) PMU.
4370 sub->pmu->read(sub);
4374 data->ret = pmu->commit_txn(pmu);
4377 raw_spin_unlock(&ctx->lock);
4380 static inline u64 perf_event_count(struct perf_event *event)
4382 return local64_read(&event->count) + atomic64_read(&event->child_count);
4386 * NMI-safe method to read a local event, that is an event that
4388 * - either for the current task, or for this CPU
4389 * - does not have inherit set, for inherited task events
4390 * will not be local and we cannot read them atomically
4391 * - must not have a pmu::count method
4393 int perf_event_read_local(struct perf_event *event, u64 *value,
4394 u64 *enabled, u64 *running)
4396 unsigned long flags;
4400 * Disabling interrupts avoids all counter scheduling (context
4401 * switches, timer based rotation and IPIs).
4403 local_irq_save(flags);
4406 * It must not be an event with inherit set, we cannot read
4407 * all child counters from atomic context.
4409 if (event->attr.inherit) {
4414 /* If this is a per-task event, it must be for current */
4415 if ((event->attach_state & PERF_ATTACH_TASK) &&
4416 event->hw.target != current) {
4421 /* If this is a per-CPU event, it must be for this CPU */
4422 if (!(event->attach_state & PERF_ATTACH_TASK) &&
4423 event->cpu != smp_processor_id()) {
4428 /* If this is a pinned event it must be running on this CPU */
4429 if (event->attr.pinned && event->oncpu != smp_processor_id()) {
4435 * If the event is currently on this CPU, its either a per-task event,
4436 * or local to this CPU. Furthermore it means its ACTIVE (otherwise
4439 if (event->oncpu == smp_processor_id())
4440 event->pmu->read(event);
4442 *value = local64_read(&event->count);
4443 if (enabled || running) {
4444 u64 now = event->shadow_ctx_time + perf_clock();
4445 u64 __enabled, __running;
4447 __perf_update_times(event, now, &__enabled, &__running);
4449 *enabled = __enabled;
4451 *running = __running;
4454 local_irq_restore(flags);
4459 static int perf_event_read(struct perf_event *event, bool group)
4461 enum perf_event_state state = READ_ONCE(event->state);
4462 int event_cpu, ret = 0;
4465 * If event is enabled and currently active on a CPU, update the
4466 * value in the event structure:
4469 if (state == PERF_EVENT_STATE_ACTIVE) {
4470 struct perf_read_data data;
4473 * Orders the ->state and ->oncpu loads such that if we see
4474 * ACTIVE we must also see the right ->oncpu.
4476 * Matches the smp_wmb() from event_sched_in().
4480 event_cpu = READ_ONCE(event->oncpu);
4481 if ((unsigned)event_cpu >= nr_cpu_ids)
4484 data = (struct perf_read_data){
4491 event_cpu = __perf_event_read_cpu(event, event_cpu);
4494 * Purposely ignore the smp_call_function_single() return
4497 * If event_cpu isn't a valid CPU it means the event got
4498 * scheduled out and that will have updated the event count.
4500 * Therefore, either way, we'll have an up-to-date event count
4503 (void)smp_call_function_single(event_cpu, __perf_event_read, &data, 1);
4507 } else if (state == PERF_EVENT_STATE_INACTIVE) {
4508 struct perf_event_context *ctx = event->ctx;
4509 unsigned long flags;
4511 raw_spin_lock_irqsave(&ctx->lock, flags);
4512 state = event->state;
4513 if (state != PERF_EVENT_STATE_INACTIVE) {
4514 raw_spin_unlock_irqrestore(&ctx->lock, flags);
4519 * May read while context is not active (e.g., thread is
4520 * blocked), in that case we cannot update context time
4522 if (ctx->is_active & EVENT_TIME) {
4523 update_context_time(ctx);
4524 update_cgrp_time_from_event(event);
4527 perf_event_update_time(event);
4529 perf_event_update_sibling_time(event);
4530 raw_spin_unlock_irqrestore(&ctx->lock, flags);
4537 * Initialize the perf_event context in a task_struct:
4539 static void __perf_event_init_context(struct perf_event_context *ctx)
4541 raw_spin_lock_init(&ctx->lock);
4542 mutex_init(&ctx->mutex);
4543 INIT_LIST_HEAD(&ctx->active_ctx_list);
4544 perf_event_groups_init(&ctx->pinned_groups);
4545 perf_event_groups_init(&ctx->flexible_groups);
4546 INIT_LIST_HEAD(&ctx->event_list);
4547 INIT_LIST_HEAD(&ctx->pinned_active);
4548 INIT_LIST_HEAD(&ctx->flexible_active);
4549 refcount_set(&ctx->refcount, 1);
4552 static struct perf_event_context *
4553 alloc_perf_context(struct pmu *pmu, struct task_struct *task)
4555 struct perf_event_context *ctx;
4557 ctx = kzalloc(sizeof(struct perf_event_context), GFP_KERNEL);
4561 __perf_event_init_context(ctx);
4563 ctx->task = get_task_struct(task);
4569 static struct task_struct *
4570 find_lively_task_by_vpid(pid_t vpid)
4572 struct task_struct *task;
4578 task = find_task_by_vpid(vpid);
4580 get_task_struct(task);
4584 return ERR_PTR(-ESRCH);
4590 * Returns a matching context with refcount and pincount.
4592 static struct perf_event_context *
4593 find_get_context(struct pmu *pmu, struct task_struct *task,
4594 struct perf_event *event)
4596 struct perf_event_context *ctx, *clone_ctx = NULL;
4597 struct perf_cpu_context *cpuctx;
4598 void *task_ctx_data = NULL;
4599 unsigned long flags;
4601 int cpu = event->cpu;
4604 /* Must be root to operate on a CPU event: */
4605 err = perf_allow_cpu(&event->attr);
4607 return ERR_PTR(err);
4609 cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
4618 ctxn = pmu->task_ctx_nr;
4622 if (event->attach_state & PERF_ATTACH_TASK_DATA) {
4623 task_ctx_data = alloc_task_ctx_data(pmu);
4624 if (!task_ctx_data) {
4631 ctx = perf_lock_task_context(task, ctxn, &flags);
4633 clone_ctx = unclone_ctx(ctx);
4636 if (task_ctx_data && !ctx->task_ctx_data) {
4637 ctx->task_ctx_data = task_ctx_data;
4638 task_ctx_data = NULL;
4640 raw_spin_unlock_irqrestore(&ctx->lock, flags);
4645 ctx = alloc_perf_context(pmu, task);
4650 if (task_ctx_data) {
4651 ctx->task_ctx_data = task_ctx_data;
4652 task_ctx_data = NULL;
4656 mutex_lock(&task->perf_event_mutex);
4658 * If it has already passed perf_event_exit_task().
4659 * we must see PF_EXITING, it takes this mutex too.
4661 if (task->flags & PF_EXITING)
4663 else if (task->perf_event_ctxp[ctxn])
4668 rcu_assign_pointer(task->perf_event_ctxp[ctxn], ctx);
4670 mutex_unlock(&task->perf_event_mutex);
4672 if (unlikely(err)) {
4681 free_task_ctx_data(pmu, task_ctx_data);
4685 free_task_ctx_data(pmu, task_ctx_data);
4686 return ERR_PTR(err);
4689 static void perf_event_free_filter(struct perf_event *event);
4690 static void perf_event_free_bpf_prog(struct perf_event *event);
4692 static void free_event_rcu(struct rcu_head *head)
4694 struct perf_event *event;
4696 event = container_of(head, struct perf_event, rcu_head);
4698 put_pid_ns(event->ns);
4699 perf_event_free_filter(event);
4700 kmem_cache_free(perf_event_cache, event);
4703 static void ring_buffer_attach(struct perf_event *event,
4704 struct perf_buffer *rb);
4706 static void detach_sb_event(struct perf_event *event)
4708 struct pmu_event_list *pel = per_cpu_ptr(&pmu_sb_events, event->cpu);
4710 raw_spin_lock(&pel->lock);
4711 list_del_rcu(&event->sb_list);
4712 raw_spin_unlock(&pel->lock);
4715 static bool is_sb_event(struct perf_event *event)
4717 struct perf_event_attr *attr = &event->attr;
4722 if (event->attach_state & PERF_ATTACH_TASK)
4725 if (attr->mmap || attr->mmap_data || attr->mmap2 ||
4726 attr->comm || attr->comm_exec ||
4727 attr->task || attr->ksymbol ||
4728 attr->context_switch || attr->text_poke ||
4734 static void unaccount_pmu_sb_event(struct perf_event *event)
4736 if (is_sb_event(event))
4737 detach_sb_event(event);
4740 static void unaccount_event_cpu(struct perf_event *event, int cpu)
4745 if (is_cgroup_event(event))
4746 atomic_dec(&per_cpu(perf_cgroup_events, cpu));
4749 #ifdef CONFIG_NO_HZ_FULL
4750 static DEFINE_SPINLOCK(nr_freq_lock);
4753 static void unaccount_freq_event_nohz(void)
4755 #ifdef CONFIG_NO_HZ_FULL
4756 spin_lock(&nr_freq_lock);
4757 if (atomic_dec_and_test(&nr_freq_events))
4758 tick_nohz_dep_clear(TICK_DEP_BIT_PERF_EVENTS);
4759 spin_unlock(&nr_freq_lock);
4763 static void unaccount_freq_event(void)
4765 if (tick_nohz_full_enabled())
4766 unaccount_freq_event_nohz();
4768 atomic_dec(&nr_freq_events);
4771 static void unaccount_event(struct perf_event *event)
4778 if (event->attach_state & (PERF_ATTACH_TASK | PERF_ATTACH_SCHED_CB))
4780 if (event->attr.mmap || event->attr.mmap_data)
4781 atomic_dec(&nr_mmap_events);
4782 if (event->attr.build_id)
4783 atomic_dec(&nr_build_id_events);
4784 if (event->attr.comm)
4785 atomic_dec(&nr_comm_events);
4786 if (event->attr.namespaces)
4787 atomic_dec(&nr_namespaces_events);
4788 if (event->attr.cgroup)
4789 atomic_dec(&nr_cgroup_events);
4790 if (event->attr.task)
4791 atomic_dec(&nr_task_events);
4792 if (event->attr.freq)
4793 unaccount_freq_event();
4794 if (event->attr.context_switch) {
4796 atomic_dec(&nr_switch_events);
4798 if (is_cgroup_event(event))
4800 if (has_branch_stack(event))
4802 if (event->attr.ksymbol)
4803 atomic_dec(&nr_ksymbol_events);
4804 if (event->attr.bpf_event)
4805 atomic_dec(&nr_bpf_events);
4806 if (event->attr.text_poke)
4807 atomic_dec(&nr_text_poke_events);
4810 if (!atomic_add_unless(&perf_sched_count, -1, 1))
4811 schedule_delayed_work(&perf_sched_work, HZ);
4814 unaccount_event_cpu(event, event->cpu);
4816 unaccount_pmu_sb_event(event);
4819 static void perf_sched_delayed(struct work_struct *work)
4821 mutex_lock(&perf_sched_mutex);
4822 if (atomic_dec_and_test(&perf_sched_count))
4823 static_branch_disable(&perf_sched_events);
4824 mutex_unlock(&perf_sched_mutex);
4828 * The following implement mutual exclusion of events on "exclusive" pmus
4829 * (PERF_PMU_CAP_EXCLUSIVE). Such pmus can only have one event scheduled
4830 * at a time, so we disallow creating events that might conflict, namely:
4832 * 1) cpu-wide events in the presence of per-task events,
4833 * 2) per-task events in the presence of cpu-wide events,
4834 * 3) two matching events on the same context.
4836 * The former two cases are handled in the allocation path (perf_event_alloc(),
4837 * _free_event()), the latter -- before the first perf_install_in_context().
4839 static int exclusive_event_init(struct perf_event *event)
4841 struct pmu *pmu = event->pmu;
4843 if (!is_exclusive_pmu(pmu))
4847 * Prevent co-existence of per-task and cpu-wide events on the
4848 * same exclusive pmu.
4850 * Negative pmu::exclusive_cnt means there are cpu-wide
4851 * events on this "exclusive" pmu, positive means there are
4854 * Since this is called in perf_event_alloc() path, event::ctx
4855 * doesn't exist yet; it is, however, safe to use PERF_ATTACH_TASK
4856 * to mean "per-task event", because unlike other attach states it
4857 * never gets cleared.
4859 if (event->attach_state & PERF_ATTACH_TASK) {
4860 if (!atomic_inc_unless_negative(&pmu->exclusive_cnt))
4863 if (!atomic_dec_unless_positive(&pmu->exclusive_cnt))
4870 static void exclusive_event_destroy(struct perf_event *event)
4872 struct pmu *pmu = event->pmu;
4874 if (!is_exclusive_pmu(pmu))
4877 /* see comment in exclusive_event_init() */
4878 if (event->attach_state & PERF_ATTACH_TASK)
4879 atomic_dec(&pmu->exclusive_cnt);
4881 atomic_inc(&pmu->exclusive_cnt);
4884 static bool exclusive_event_match(struct perf_event *e1, struct perf_event *e2)
4886 if ((e1->pmu == e2->pmu) &&
4887 (e1->cpu == e2->cpu ||
4894 static bool exclusive_event_installable(struct perf_event *event,
4895 struct perf_event_context *ctx)
4897 struct perf_event *iter_event;
4898 struct pmu *pmu = event->pmu;
4900 lockdep_assert_held(&ctx->mutex);
4902 if (!is_exclusive_pmu(pmu))
4905 list_for_each_entry(iter_event, &ctx->event_list, event_entry) {
4906 if (exclusive_event_match(iter_event, event))
4913 static void perf_addr_filters_splice(struct perf_event *event,
4914 struct list_head *head);
4916 static void _free_event(struct perf_event *event)
4918 irq_work_sync(&event->pending);
4920 unaccount_event(event);
4922 security_perf_event_free(event);
4926 * Can happen when we close an event with re-directed output.
4928 * Since we have a 0 refcount, perf_mmap_close() will skip
4929 * over us; possibly making our ring_buffer_put() the last.
4931 mutex_lock(&event->mmap_mutex);
4932 ring_buffer_attach(event, NULL);
4933 mutex_unlock(&event->mmap_mutex);
4936 if (is_cgroup_event(event))
4937 perf_detach_cgroup(event);
4939 if (!event->parent) {
4940 if (event->attr.sample_type & PERF_SAMPLE_CALLCHAIN)
4941 put_callchain_buffers();
4944 perf_event_free_bpf_prog(event);
4945 perf_addr_filters_splice(event, NULL);
4946 kfree(event->addr_filter_ranges);
4949 event->destroy(event);
4952 * Must be after ->destroy(), due to uprobe_perf_close() using
4955 if (event->hw.target)
4956 put_task_struct(event->hw.target);
4959 * perf_event_free_task() relies on put_ctx() being 'last', in particular
4960 * all task references must be cleaned up.
4963 put_ctx(event->ctx);
4965 exclusive_event_destroy(event);
4966 module_put(event->pmu->module);
4968 call_rcu(&event->rcu_head, free_event_rcu);
4972 * Used to free events which have a known refcount of 1, such as in error paths
4973 * where the event isn't exposed yet and inherited events.
4975 static void free_event(struct perf_event *event)
4977 if (WARN(atomic_long_cmpxchg(&event->refcount, 1, 0) != 1,
4978 "unexpected event refcount: %ld; ptr=%p\n",
4979 atomic_long_read(&event->refcount), event)) {
4980 /* leak to avoid use-after-free */
4988 * Remove user event from the owner task.
4990 static void perf_remove_from_owner(struct perf_event *event)
4992 struct task_struct *owner;
4996 * Matches the smp_store_release() in perf_event_exit_task(). If we
4997 * observe !owner it means the list deletion is complete and we can
4998 * indeed free this event, otherwise we need to serialize on
4999 * owner->perf_event_mutex.
5001 owner = READ_ONCE(event->owner);
5004 * Since delayed_put_task_struct() also drops the last
5005 * task reference we can safely take a new reference
5006 * while holding the rcu_read_lock().
5008 get_task_struct(owner);
5014 * If we're here through perf_event_exit_task() we're already
5015 * holding ctx->mutex which would be an inversion wrt. the
5016 * normal lock order.
5018 * However we can safely take this lock because its the child
5021 mutex_lock_nested(&owner->perf_event_mutex, SINGLE_DEPTH_NESTING);
5024 * We have to re-check the event->owner field, if it is cleared
5025 * we raced with perf_event_exit_task(), acquiring the mutex
5026 * ensured they're done, and we can proceed with freeing the
5030 list_del_init(&event->owner_entry);
5031 smp_store_release(&event->owner, NULL);
5033 mutex_unlock(&owner->perf_event_mutex);
5034 put_task_struct(owner);
5038 static void put_event(struct perf_event *event)
5040 if (!atomic_long_dec_and_test(&event->refcount))
5047 * Kill an event dead; while event:refcount will preserve the event
5048 * object, it will not preserve its functionality. Once the last 'user'
5049 * gives up the object, we'll destroy the thing.
5051 int perf_event_release_kernel(struct perf_event *event)
5053 struct perf_event_context *ctx = event->ctx;
5054 struct perf_event *child, *tmp;
5055 LIST_HEAD(free_list);
5058 * If we got here through err_file: fput(event_file); we will not have
5059 * attached to a context yet.
5062 WARN_ON_ONCE(event->attach_state &
5063 (PERF_ATTACH_CONTEXT|PERF_ATTACH_GROUP));
5067 if (!is_kernel_event(event))
5068 perf_remove_from_owner(event);
5070 ctx = perf_event_ctx_lock(event);
5071 WARN_ON_ONCE(ctx->parent_ctx);
5072 perf_remove_from_context(event, DETACH_GROUP);
5074 raw_spin_lock_irq(&ctx->lock);
5076 * Mark this event as STATE_DEAD, there is no external reference to it
5079 * Anybody acquiring event->child_mutex after the below loop _must_
5080 * also see this, most importantly inherit_event() which will avoid
5081 * placing more children on the list.
5083 * Thus this guarantees that we will in fact observe and kill _ALL_
5086 event->state = PERF_EVENT_STATE_DEAD;
5087 raw_spin_unlock_irq(&ctx->lock);
5089 perf_event_ctx_unlock(event, ctx);
5092 mutex_lock(&event->child_mutex);
5093 list_for_each_entry(child, &event->child_list, child_list) {
5096 * Cannot change, child events are not migrated, see the
5097 * comment with perf_event_ctx_lock_nested().
5099 ctx = READ_ONCE(child->ctx);
5101 * Since child_mutex nests inside ctx::mutex, we must jump
5102 * through hoops. We start by grabbing a reference on the ctx.
5104 * Since the event cannot get freed while we hold the
5105 * child_mutex, the context must also exist and have a !0
5111 * Now that we have a ctx ref, we can drop child_mutex, and
5112 * acquire ctx::mutex without fear of it going away. Then we
5113 * can re-acquire child_mutex.
5115 mutex_unlock(&event->child_mutex);
5116 mutex_lock(&ctx->mutex);
5117 mutex_lock(&event->child_mutex);
5120 * Now that we hold ctx::mutex and child_mutex, revalidate our
5121 * state, if child is still the first entry, it didn't get freed
5122 * and we can continue doing so.
5124 tmp = list_first_entry_or_null(&event->child_list,
5125 struct perf_event, child_list);
5127 perf_remove_from_context(child, DETACH_GROUP);
5128 list_move(&child->child_list, &free_list);
5130 * This matches the refcount bump in inherit_event();
5131 * this can't be the last reference.
5136 mutex_unlock(&event->child_mutex);
5137 mutex_unlock(&ctx->mutex);
5141 mutex_unlock(&event->child_mutex);
5143 list_for_each_entry_safe(child, tmp, &free_list, child_list) {
5144 void *var = &child->ctx->refcount;
5146 list_del(&child->child_list);
5150 * Wake any perf_event_free_task() waiting for this event to be
5153 smp_mb(); /* pairs with wait_var_event() */
5158 put_event(event); /* Must be the 'last' reference */
5161 EXPORT_SYMBOL_GPL(perf_event_release_kernel);
5164 * Called when the last reference to the file is gone.
5166 static int perf_release(struct inode *inode, struct file *file)
5168 perf_event_release_kernel(file->private_data);
5172 static u64 __perf_event_read_value(struct perf_event *event, u64 *enabled, u64 *running)
5174 struct perf_event *child;
5180 mutex_lock(&event->child_mutex);
5182 (void)perf_event_read(event, false);
5183 total += perf_event_count(event);
5185 *enabled += event->total_time_enabled +
5186 atomic64_read(&event->child_total_time_enabled);
5187 *running += event->total_time_running +
5188 atomic64_read(&event->child_total_time_running);
5190 list_for_each_entry(child, &event->child_list, child_list) {
5191 (void)perf_event_read(child, false);
5192 total += perf_event_count(child);
5193 *enabled += child->total_time_enabled;
5194 *running += child->total_time_running;
5196 mutex_unlock(&event->child_mutex);
5201 u64 perf_event_read_value(struct perf_event *event, u64 *enabled, u64 *running)
5203 struct perf_event_context *ctx;
5206 ctx = perf_event_ctx_lock(event);
5207 count = __perf_event_read_value(event, enabled, running);
5208 perf_event_ctx_unlock(event, ctx);
5212 EXPORT_SYMBOL_GPL(perf_event_read_value);
5214 static int __perf_read_group_add(struct perf_event *leader,
5215 u64 read_format, u64 *values)
5217 struct perf_event_context *ctx = leader->ctx;
5218 struct perf_event *sub;
5219 unsigned long flags;
5220 int n = 1; /* skip @nr */
5223 ret = perf_event_read(leader, true);
5227 raw_spin_lock_irqsave(&ctx->lock, flags);
5230 * Since we co-schedule groups, {enabled,running} times of siblings
5231 * will be identical to those of the leader, so we only publish one
5234 if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED) {
5235 values[n++] += leader->total_time_enabled +
5236 atomic64_read(&leader->child_total_time_enabled);
5239 if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING) {
5240 values[n++] += leader->total_time_running +
5241 atomic64_read(&leader->child_total_time_running);
5245 * Write {count,id} tuples for every sibling.
5247 values[n++] += perf_event_count(leader);
5248 if (read_format & PERF_FORMAT_ID)
5249 values[n++] = primary_event_id(leader);
5251 for_each_sibling_event(sub, leader) {
5252 values[n++] += perf_event_count(sub);
5253 if (read_format & PERF_FORMAT_ID)
5254 values[n++] = primary_event_id(sub);
5257 raw_spin_unlock_irqrestore(&ctx->lock, flags);
5261 static int perf_read_group(struct perf_event *event,
5262 u64 read_format, char __user *buf)
5264 struct perf_event *leader = event->group_leader, *child;
5265 struct perf_event_context *ctx = leader->ctx;
5269 lockdep_assert_held(&ctx->mutex);
5271 values = kzalloc(event->read_size, GFP_KERNEL);
5275 values[0] = 1 + leader->nr_siblings;
5278 * By locking the child_mutex of the leader we effectively
5279 * lock the child list of all siblings.. XXX explain how.
5281 mutex_lock(&leader->child_mutex);
5283 ret = __perf_read_group_add(leader, read_format, values);
5287 list_for_each_entry(child, &leader->child_list, child_list) {
5288 ret = __perf_read_group_add(child, read_format, values);
5293 mutex_unlock(&leader->child_mutex);
5295 ret = event->read_size;
5296 if (copy_to_user(buf, values, event->read_size))
5301 mutex_unlock(&leader->child_mutex);
5307 static int perf_read_one(struct perf_event *event,
5308 u64 read_format, char __user *buf)
5310 u64 enabled, running;
5314 values[n++] = __perf_event_read_value(event, &enabled, &running);
5315 if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED)
5316 values[n++] = enabled;
5317 if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING)
5318 values[n++] = running;
5319 if (read_format & PERF_FORMAT_ID)
5320 values[n++] = primary_event_id(event);
5322 if (copy_to_user(buf, values, n * sizeof(u64)))
5325 return n * sizeof(u64);
5328 static bool is_event_hup(struct perf_event *event)
5332 if (event->state > PERF_EVENT_STATE_EXIT)
5335 mutex_lock(&event->child_mutex);
5336 no_children = list_empty(&event->child_list);
5337 mutex_unlock(&event->child_mutex);
5342 * Read the performance event - simple non blocking version for now
5345 __perf_read(struct perf_event *event, char __user *buf, size_t count)
5347 u64 read_format = event->attr.read_format;
5351 * Return end-of-file for a read on an event that is in
5352 * error state (i.e. because it was pinned but it couldn't be
5353 * scheduled on to the CPU at some point).
5355 if (event->state == PERF_EVENT_STATE_ERROR)
5358 if (count < event->read_size)
5361 WARN_ON_ONCE(event->ctx->parent_ctx);
5362 if (read_format & PERF_FORMAT_GROUP)
5363 ret = perf_read_group(event, read_format, buf);
5365 ret = perf_read_one(event, read_format, buf);
5371 perf_read(struct file *file, char __user *buf, size_t count, loff_t *ppos)
5373 struct perf_event *event = file->private_data;
5374 struct perf_event_context *ctx;
5377 ret = security_perf_event_read(event);
5381 ctx = perf_event_ctx_lock(event);
5382 ret = __perf_read(event, buf, count);
5383 perf_event_ctx_unlock(event, ctx);
5388 static __poll_t perf_poll(struct file *file, poll_table *wait)
5390 struct perf_event *event = file->private_data;
5391 struct perf_buffer *rb;
5392 __poll_t events = EPOLLHUP;
5394 poll_wait(file, &event->waitq, wait);
5396 if (is_event_hup(event))
5400 * Pin the event->rb by taking event->mmap_mutex; otherwise
5401 * perf_event_set_output() can swizzle our rb and make us miss wakeups.
5403 mutex_lock(&event->mmap_mutex);
5406 events = atomic_xchg(&rb->poll, 0);
5407 mutex_unlock(&event->mmap_mutex);
5411 static void _perf_event_reset(struct perf_event *event)
5413 (void)perf_event_read(event, false);
5414 local64_set(&event->count, 0);
5415 perf_event_update_userpage(event);
5418 /* Assume it's not an event with inherit set. */
5419 u64 perf_event_pause(struct perf_event *event, bool reset)
5421 struct perf_event_context *ctx;
5424 ctx = perf_event_ctx_lock(event);
5425 WARN_ON_ONCE(event->attr.inherit);
5426 _perf_event_disable(event);
5427 count = local64_read(&event->count);
5429 local64_set(&event->count, 0);
5430 perf_event_ctx_unlock(event, ctx);
5434 EXPORT_SYMBOL_GPL(perf_event_pause);
5437 * Holding the top-level event's child_mutex means that any
5438 * descendant process that has inherited this event will block
5439 * in perf_event_exit_event() if it goes to exit, thus satisfying the
5440 * task existence requirements of perf_event_enable/disable.
5442 static void perf_event_for_each_child(struct perf_event *event,
5443 void (*func)(struct perf_event *))
5445 struct perf_event *child;
5447 WARN_ON_ONCE(event->ctx->parent_ctx);
5449 mutex_lock(&event->child_mutex);
5451 list_for_each_entry(child, &event->child_list, child_list)
5453 mutex_unlock(&event->child_mutex);
5456 static void perf_event_for_each(struct perf_event *event,
5457 void (*func)(struct perf_event *))
5459 struct perf_event_context *ctx = event->ctx;
5460 struct perf_event *sibling;
5462 lockdep_assert_held(&ctx->mutex);
5464 event = event->group_leader;
5466 perf_event_for_each_child(event, func);
5467 for_each_sibling_event(sibling, event)
5468 perf_event_for_each_child(sibling, func);
5471 static void __perf_event_period(struct perf_event *event,
5472 struct perf_cpu_context *cpuctx,
5473 struct perf_event_context *ctx,
5476 u64 value = *((u64 *)info);
5479 if (event->attr.freq) {
5480 event->attr.sample_freq = value;
5482 event->attr.sample_period = value;
5483 event->hw.sample_period = value;
5486 active = (event->state == PERF_EVENT_STATE_ACTIVE);
5488 perf_pmu_disable(ctx->pmu);
5490 * We could be throttled; unthrottle now to avoid the tick
5491 * trying to unthrottle while we already re-started the event.
5493 if (event->hw.interrupts == MAX_INTERRUPTS) {
5494 event->hw.interrupts = 0;
5495 perf_log_throttle(event, 1);
5497 event->pmu->stop(event, PERF_EF_UPDATE);
5500 local64_set(&event->hw.period_left, 0);
5503 event->pmu->start(event, PERF_EF_RELOAD);
5504 perf_pmu_enable(ctx->pmu);
5508 static int perf_event_check_period(struct perf_event *event, u64 value)
5510 return event->pmu->check_period(event, value);
5513 static int _perf_event_period(struct perf_event *event, u64 value)
5515 if (!is_sampling_event(event))
5521 if (event->attr.freq && value > sysctl_perf_event_sample_rate)
5524 if (perf_event_check_period(event, value))
5527 if (!event->attr.freq && (value & (1ULL << 63)))
5530 event_function_call(event, __perf_event_period, &value);
5535 int perf_event_period(struct perf_event *event, u64 value)
5537 struct perf_event_context *ctx;
5540 ctx = perf_event_ctx_lock(event);
5541 ret = _perf_event_period(event, value);
5542 perf_event_ctx_unlock(event, ctx);
5546 EXPORT_SYMBOL_GPL(perf_event_period);
5548 static const struct file_operations perf_fops;
5550 static inline int perf_fget_light(int fd, struct fd *p)
5552 struct fd f = fdget(fd);
5556 if (f.file->f_op != &perf_fops) {
5564 static int perf_event_set_output(struct perf_event *event,
5565 struct perf_event *output_event);
5566 static int perf_event_set_filter(struct perf_event *event, void __user *arg);
5567 static int perf_event_set_bpf_prog(struct perf_event *event, u32 prog_fd);
5568 static int perf_copy_attr(struct perf_event_attr __user *uattr,
5569 struct perf_event_attr *attr);
5571 static long _perf_ioctl(struct perf_event *event, unsigned int cmd, unsigned long arg)
5573 void (*func)(struct perf_event *);
5577 case PERF_EVENT_IOC_ENABLE:
5578 func = _perf_event_enable;
5580 case PERF_EVENT_IOC_DISABLE:
5581 func = _perf_event_disable;
5583 case PERF_EVENT_IOC_RESET:
5584 func = _perf_event_reset;
5587 case PERF_EVENT_IOC_REFRESH:
5588 return _perf_event_refresh(event, arg);
5590 case PERF_EVENT_IOC_PERIOD:
5594 if (copy_from_user(&value, (u64 __user *)arg, sizeof(value)))
5597 return _perf_event_period(event, value);
5599 case PERF_EVENT_IOC_ID:
5601 u64 id = primary_event_id(event);
5603 if (copy_to_user((void __user *)arg, &id, sizeof(id)))
5608 case PERF_EVENT_IOC_SET_OUTPUT:
5612 struct perf_event *output_event;
5614 ret = perf_fget_light(arg, &output);
5617 output_event = output.file->private_data;
5618 ret = perf_event_set_output(event, output_event);
5621 ret = perf_event_set_output(event, NULL);
5626 case PERF_EVENT_IOC_SET_FILTER:
5627 return perf_event_set_filter(event, (void __user *)arg);
5629 case PERF_EVENT_IOC_SET_BPF:
5630 return perf_event_set_bpf_prog(event, arg);
5632 case PERF_EVENT_IOC_PAUSE_OUTPUT: {
5633 struct perf_buffer *rb;
5636 rb = rcu_dereference(event->rb);
5637 if (!rb || !rb->nr_pages) {
5641 rb_toggle_paused(rb, !!arg);
5646 case PERF_EVENT_IOC_QUERY_BPF:
5647 return perf_event_query_prog_array(event, (void __user *)arg);
5649 case PERF_EVENT_IOC_MODIFY_ATTRIBUTES: {
5650 struct perf_event_attr new_attr;
5651 int err = perf_copy_attr((struct perf_event_attr __user *)arg,
5657 return perf_event_modify_attr(event, &new_attr);
5663 if (flags & PERF_IOC_FLAG_GROUP)
5664 perf_event_for_each(event, func);
5666 perf_event_for_each_child(event, func);
5671 static long perf_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
5673 struct perf_event *event = file->private_data;
5674 struct perf_event_context *ctx;
5677 /* Treat ioctl like writes as it is likely a mutating operation. */
5678 ret = security_perf_event_write(event);
5682 ctx = perf_event_ctx_lock(event);
5683 ret = _perf_ioctl(event, cmd, arg);
5684 perf_event_ctx_unlock(event, ctx);
5689 #ifdef CONFIG_COMPAT
5690 static long perf_compat_ioctl(struct file *file, unsigned int cmd,
5693 switch (_IOC_NR(cmd)) {
5694 case _IOC_NR(PERF_EVENT_IOC_SET_FILTER):
5695 case _IOC_NR(PERF_EVENT_IOC_ID):
5696 case _IOC_NR(PERF_EVENT_IOC_QUERY_BPF):
5697 case _IOC_NR(PERF_EVENT_IOC_MODIFY_ATTRIBUTES):
5698 /* Fix up pointer size (usually 4 -> 8 in 32-on-64-bit case */
5699 if (_IOC_SIZE(cmd) == sizeof(compat_uptr_t)) {
5700 cmd &= ~IOCSIZE_MASK;
5701 cmd |= sizeof(void *) << IOCSIZE_SHIFT;
5705 return perf_ioctl(file, cmd, arg);
5708 # define perf_compat_ioctl NULL
5711 int perf_event_task_enable(void)
5713 struct perf_event_context *ctx;
5714 struct perf_event *event;
5716 mutex_lock(¤t->perf_event_mutex);
5717 list_for_each_entry(event, ¤t->perf_event_list, owner_entry) {
5718 ctx = perf_event_ctx_lock(event);
5719 perf_event_for_each_child(event, _perf_event_enable);
5720 perf_event_ctx_unlock(event, ctx);
5722 mutex_unlock(¤t->perf_event_mutex);
5727 int perf_event_task_disable(void)
5729 struct perf_event_context *ctx;
5730 struct perf_event *event;
5732 mutex_lock(¤t->perf_event_mutex);
5733 list_for_each_entry(event, ¤t->perf_event_list, owner_entry) {
5734 ctx = perf_event_ctx_lock(event);
5735 perf_event_for_each_child(event, _perf_event_disable);
5736 perf_event_ctx_unlock(event, ctx);
5738 mutex_unlock(¤t->perf_event_mutex);
5743 static int perf_event_index(struct perf_event *event)
5745 if (event->hw.state & PERF_HES_STOPPED)
5748 if (event->state != PERF_EVENT_STATE_ACTIVE)
5751 return event->pmu->event_idx(event);
5754 static void calc_timer_values(struct perf_event *event,
5761 *now = perf_clock();
5762 ctx_time = event->shadow_ctx_time + *now;
5763 __perf_update_times(event, ctx_time, enabled, running);
5766 static void perf_event_init_userpage(struct perf_event *event)
5768 struct perf_event_mmap_page *userpg;
5769 struct perf_buffer *rb;
5772 rb = rcu_dereference(event->rb);
5776 userpg = rb->user_page;
5778 /* Allow new userspace to detect that bit 0 is deprecated */
5779 userpg->cap_bit0_is_deprecated = 1;
5780 userpg->size = offsetof(struct perf_event_mmap_page, __reserved);
5781 userpg->data_offset = PAGE_SIZE;
5782 userpg->data_size = perf_data_size(rb);
5788 void __weak arch_perf_update_userpage(
5789 struct perf_event *event, struct perf_event_mmap_page *userpg, u64 now)
5794 * Callers need to ensure there can be no nesting of this function, otherwise
5795 * the seqlock logic goes bad. We can not serialize this because the arch
5796 * code calls this from NMI context.
5798 void perf_event_update_userpage(struct perf_event *event)
5800 struct perf_event_mmap_page *userpg;
5801 struct perf_buffer *rb;
5802 u64 enabled, running, now;
5805 rb = rcu_dereference(event->rb);
5810 * compute total_time_enabled, total_time_running
5811 * based on snapshot values taken when the event
5812 * was last scheduled in.
5814 * we cannot simply called update_context_time()
5815 * because of locking issue as we can be called in
5818 calc_timer_values(event, &now, &enabled, &running);
5820 userpg = rb->user_page;
5822 * Disable preemption to guarantee consistent time stamps are stored to
5828 userpg->index = perf_event_index(event);
5829 userpg->offset = perf_event_count(event);
5831 userpg->offset -= local64_read(&event->hw.prev_count);
5833 userpg->time_enabled = enabled +
5834 atomic64_read(&event->child_total_time_enabled);
5836 userpg->time_running = running +
5837 atomic64_read(&event->child_total_time_running);
5839 arch_perf_update_userpage(event, userpg, now);
5847 EXPORT_SYMBOL_GPL(perf_event_update_userpage);
5849 static vm_fault_t perf_mmap_fault(struct vm_fault *vmf)
5851 struct perf_event *event = vmf->vma->vm_file->private_data;
5852 struct perf_buffer *rb;
5853 vm_fault_t ret = VM_FAULT_SIGBUS;
5855 if (vmf->flags & FAULT_FLAG_MKWRITE) {
5856 if (vmf->pgoff == 0)
5862 rb = rcu_dereference(event->rb);
5866 if (vmf->pgoff && (vmf->flags & FAULT_FLAG_WRITE))
5869 vmf->page = perf_mmap_to_page(rb, vmf->pgoff);
5873 get_page(vmf->page);
5874 vmf->page->mapping = vmf->vma->vm_file->f_mapping;
5875 vmf->page->index = vmf->pgoff;
5884 static void ring_buffer_attach(struct perf_event *event,
5885 struct perf_buffer *rb)
5887 struct perf_buffer *old_rb = NULL;
5888 unsigned long flags;
5892 * Should be impossible, we set this when removing
5893 * event->rb_entry and wait/clear when adding event->rb_entry.
5895 WARN_ON_ONCE(event->rcu_pending);
5898 spin_lock_irqsave(&old_rb->event_lock, flags);
5899 list_del_rcu(&event->rb_entry);
5900 spin_unlock_irqrestore(&old_rb->event_lock, flags);
5902 event->rcu_batches = get_state_synchronize_rcu();
5903 event->rcu_pending = 1;
5907 if (event->rcu_pending) {
5908 cond_synchronize_rcu(event->rcu_batches);
5909 event->rcu_pending = 0;
5912 spin_lock_irqsave(&rb->event_lock, flags);
5913 list_add_rcu(&event->rb_entry, &rb->event_list);
5914 spin_unlock_irqrestore(&rb->event_lock, flags);
5918 * Avoid racing with perf_mmap_close(AUX): stop the event
5919 * before swizzling the event::rb pointer; if it's getting
5920 * unmapped, its aux_mmap_count will be 0 and it won't
5921 * restart. See the comment in __perf_pmu_output_stop().
5923 * Data will inevitably be lost when set_output is done in
5924 * mid-air, but then again, whoever does it like this is
5925 * not in for the data anyway.
5928 perf_event_stop(event, 0);
5930 rcu_assign_pointer(event->rb, rb);
5933 ring_buffer_put(old_rb);
5935 * Since we detached before setting the new rb, so that we
5936 * could attach the new rb, we could have missed a wakeup.
5939 wake_up_all(&event->waitq);
5943 static void ring_buffer_wakeup(struct perf_event *event)
5945 struct perf_buffer *rb;
5948 rb = rcu_dereference(event->rb);
5950 list_for_each_entry_rcu(event, &rb->event_list, rb_entry)
5951 wake_up_all(&event->waitq);
5956 struct perf_buffer *ring_buffer_get(struct perf_event *event)
5958 struct perf_buffer *rb;
5961 rb = rcu_dereference(event->rb);
5963 if (!refcount_inc_not_zero(&rb->refcount))
5971 void ring_buffer_put(struct perf_buffer *rb)
5973 if (!refcount_dec_and_test(&rb->refcount))
5976 WARN_ON_ONCE(!list_empty(&rb->event_list));
5978 call_rcu(&rb->rcu_head, rb_free_rcu);
5981 static void perf_mmap_open(struct vm_area_struct *vma)
5983 struct perf_event *event = vma->vm_file->private_data;
5985 atomic_inc(&event->mmap_count);
5986 atomic_inc(&event->rb->mmap_count);
5989 atomic_inc(&event->rb->aux_mmap_count);
5991 if (event->pmu->event_mapped)
5992 event->pmu->event_mapped(event, vma->vm_mm);
5995 static void perf_pmu_output_stop(struct perf_event *event);
5998 * A buffer can be mmap()ed multiple times; either directly through the same
5999 * event, or through other events by use of perf_event_set_output().
6001 * In order to undo the VM accounting done by perf_mmap() we need to destroy
6002 * the buffer here, where we still have a VM context. This means we need
6003 * to detach all events redirecting to us.
6005 static void perf_mmap_close(struct vm_area_struct *vma)
6007 struct perf_event *event = vma->vm_file->private_data;
6008 struct perf_buffer *rb = ring_buffer_get(event);
6009 struct user_struct *mmap_user = rb->mmap_user;
6010 int mmap_locked = rb->mmap_locked;
6011 unsigned long size = perf_data_size(rb);
6012 bool detach_rest = false;
6014 if (event->pmu->event_unmapped)
6015 event->pmu->event_unmapped(event, vma->vm_mm);
6018 * rb->aux_mmap_count will always drop before rb->mmap_count and
6019 * event->mmap_count, so it is ok to use event->mmap_mutex to
6020 * serialize with perf_mmap here.
6022 if (rb_has_aux(rb) && vma->vm_pgoff == rb->aux_pgoff &&
6023 atomic_dec_and_mutex_lock(&rb->aux_mmap_count, &event->mmap_mutex)) {
6025 * Stop all AUX events that are writing to this buffer,
6026 * so that we can free its AUX pages and corresponding PMU
6027 * data. Note that after rb::aux_mmap_count dropped to zero,
6028 * they won't start any more (see perf_aux_output_begin()).
6030 perf_pmu_output_stop(event);
6032 /* now it's safe to free the pages */
6033 atomic_long_sub(rb->aux_nr_pages - rb->aux_mmap_locked, &mmap_user->locked_vm);
6034 atomic64_sub(rb->aux_mmap_locked, &vma->vm_mm->pinned_vm);
6036 /* this has to be the last one */
6038 WARN_ON_ONCE(refcount_read(&rb->aux_refcount));
6040 mutex_unlock(&event->mmap_mutex);
6043 if (atomic_dec_and_test(&rb->mmap_count))
6046 if (!atomic_dec_and_mutex_lock(&event->mmap_count, &event->mmap_mutex))
6049 ring_buffer_attach(event, NULL);
6050 mutex_unlock(&event->mmap_mutex);
6052 /* If there's still other mmap()s of this buffer, we're done. */
6057 * No other mmap()s, detach from all other events that might redirect
6058 * into the now unreachable buffer. Somewhat complicated by the
6059 * fact that rb::event_lock otherwise nests inside mmap_mutex.
6063 list_for_each_entry_rcu(event, &rb->event_list, rb_entry) {
6064 if (!atomic_long_inc_not_zero(&event->refcount)) {
6066 * This event is en-route to free_event() which will
6067 * detach it and remove it from the list.
6073 mutex_lock(&event->mmap_mutex);
6075 * Check we didn't race with perf_event_set_output() which can
6076 * swizzle the rb from under us while we were waiting to
6077 * acquire mmap_mutex.
6079 * If we find a different rb; ignore this event, a next
6080 * iteration will no longer find it on the list. We have to
6081 * still restart the iteration to make sure we're not now
6082 * iterating the wrong list.
6084 if (event->rb == rb)
6085 ring_buffer_attach(event, NULL);
6087 mutex_unlock(&event->mmap_mutex);
6091 * Restart the iteration; either we're on the wrong list or
6092 * destroyed its integrity by doing a deletion.
6099 * It could be there's still a few 0-ref events on the list; they'll
6100 * get cleaned up by free_event() -- they'll also still have their
6101 * ref on the rb and will free it whenever they are done with it.
6103 * Aside from that, this buffer is 'fully' detached and unmapped,
6104 * undo the VM accounting.
6107 atomic_long_sub((size >> PAGE_SHIFT) + 1 - mmap_locked,
6108 &mmap_user->locked_vm);
6109 atomic64_sub(mmap_locked, &vma->vm_mm->pinned_vm);
6110 free_uid(mmap_user);
6113 ring_buffer_put(rb); /* could be last */
6116 static const struct vm_operations_struct perf_mmap_vmops = {
6117 .open = perf_mmap_open,
6118 .close = perf_mmap_close, /* non mergeable */
6119 .fault = perf_mmap_fault,
6120 .page_mkwrite = perf_mmap_fault,
6123 static int perf_mmap(struct file *file, struct vm_area_struct *vma)
6125 struct perf_event *event = file->private_data;
6126 unsigned long user_locked, user_lock_limit;
6127 struct user_struct *user = current_user();
6128 struct perf_buffer *rb = NULL;
6129 unsigned long locked, lock_limit;
6130 unsigned long vma_size;
6131 unsigned long nr_pages;
6132 long user_extra = 0, extra = 0;
6133 int ret = 0, flags = 0;
6136 * Don't allow mmap() of inherited per-task counters. This would
6137 * create a performance issue due to all children writing to the
6140 if (event->cpu == -1 && event->attr.inherit)
6143 if (!(vma->vm_flags & VM_SHARED))
6146 ret = security_perf_event_read(event);
6150 vma_size = vma->vm_end - vma->vm_start;
6152 if (vma->vm_pgoff == 0) {
6153 nr_pages = (vma_size / PAGE_SIZE) - 1;
6156 * AUX area mapping: if rb->aux_nr_pages != 0, it's already
6157 * mapped, all subsequent mappings should have the same size
6158 * and offset. Must be above the normal perf buffer.
6160 u64 aux_offset, aux_size;
6165 nr_pages = vma_size / PAGE_SIZE;
6167 mutex_lock(&event->mmap_mutex);
6174 aux_offset = READ_ONCE(rb->user_page->aux_offset);
6175 aux_size = READ_ONCE(rb->user_page->aux_size);
6177 if (aux_offset < perf_data_size(rb) + PAGE_SIZE)
6180 if (aux_offset != vma->vm_pgoff << PAGE_SHIFT)
6183 /* already mapped with a different offset */
6184 if (rb_has_aux(rb) && rb->aux_pgoff != vma->vm_pgoff)
6187 if (aux_size != vma_size || aux_size != nr_pages * PAGE_SIZE)
6190 /* already mapped with a different size */
6191 if (rb_has_aux(rb) && rb->aux_nr_pages != nr_pages)
6194 if (!is_power_of_2(nr_pages))
6197 if (!atomic_inc_not_zero(&rb->mmap_count))
6200 if (rb_has_aux(rb)) {
6201 atomic_inc(&rb->aux_mmap_count);
6206 atomic_set(&rb->aux_mmap_count, 1);
6207 user_extra = nr_pages;
6213 * If we have rb pages ensure they're a power-of-two number, so we
6214 * can do bitmasks instead of modulo.
6216 if (nr_pages != 0 && !is_power_of_2(nr_pages))
6219 if (vma_size != PAGE_SIZE * (1 + nr_pages))
6222 WARN_ON_ONCE(event->ctx->parent_ctx);
6224 mutex_lock(&event->mmap_mutex);
6226 if (event->rb->nr_pages != nr_pages) {
6231 if (!atomic_inc_not_zero(&event->rb->mmap_count)) {
6233 * Raced against perf_mmap_close() through
6234 * perf_event_set_output(). Try again, hope for better
6237 mutex_unlock(&event->mmap_mutex);
6244 user_extra = nr_pages + 1;
6247 user_lock_limit = sysctl_perf_event_mlock >> (PAGE_SHIFT - 10);
6250 * Increase the limit linearly with more CPUs:
6252 user_lock_limit *= num_online_cpus();
6254 user_locked = atomic_long_read(&user->locked_vm);
6257 * sysctl_perf_event_mlock may have changed, so that
6258 * user->locked_vm > user_lock_limit
6260 if (user_locked > user_lock_limit)
6261 user_locked = user_lock_limit;
6262 user_locked += user_extra;
6264 if (user_locked > user_lock_limit) {
6266 * charge locked_vm until it hits user_lock_limit;
6267 * charge the rest from pinned_vm
6269 extra = user_locked - user_lock_limit;
6270 user_extra -= extra;
6273 lock_limit = rlimit(RLIMIT_MEMLOCK);
6274 lock_limit >>= PAGE_SHIFT;
6275 locked = atomic64_read(&vma->vm_mm->pinned_vm) + extra;
6277 if ((locked > lock_limit) && perf_is_paranoid() &&
6278 !capable(CAP_IPC_LOCK)) {
6283 WARN_ON(!rb && event->rb);
6285 if (vma->vm_flags & VM_WRITE)
6286 flags |= RING_BUFFER_WRITABLE;
6289 rb = rb_alloc(nr_pages,
6290 event->attr.watermark ? event->attr.wakeup_watermark : 0,
6298 atomic_set(&rb->mmap_count, 1);
6299 rb->mmap_user = get_current_user();
6300 rb->mmap_locked = extra;
6302 ring_buffer_attach(event, rb);
6304 perf_event_init_userpage(event);
6305 perf_event_update_userpage(event);
6307 ret = rb_alloc_aux(rb, event, vma->vm_pgoff, nr_pages,
6308 event->attr.aux_watermark, flags);
6310 rb->aux_mmap_locked = extra;
6315 atomic_long_add(user_extra, &user->locked_vm);
6316 atomic64_add(extra, &vma->vm_mm->pinned_vm);
6318 atomic_inc(&event->mmap_count);
6320 atomic_dec(&rb->mmap_count);
6323 mutex_unlock(&event->mmap_mutex);
6326 * Since pinned accounting is per vm we cannot allow fork() to copy our
6329 vma->vm_flags |= VM_DONTCOPY | VM_DONTEXPAND | VM_DONTDUMP;
6330 vma->vm_ops = &perf_mmap_vmops;
6332 if (event->pmu->event_mapped)
6333 event->pmu->event_mapped(event, vma->vm_mm);
6338 static int perf_fasync(int fd, struct file *filp, int on)
6340 struct inode *inode = file_inode(filp);
6341 struct perf_event *event = filp->private_data;
6345 retval = fasync_helper(fd, filp, on, &event->fasync);
6346 inode_unlock(inode);
6354 static const struct file_operations perf_fops = {
6355 .llseek = no_llseek,
6356 .release = perf_release,
6359 .unlocked_ioctl = perf_ioctl,
6360 .compat_ioctl = perf_compat_ioctl,
6362 .fasync = perf_fasync,
6368 * If there's data, ensure we set the poll() state and publish everything
6369 * to user-space before waking everybody up.
6372 static inline struct fasync_struct **perf_event_fasync(struct perf_event *event)
6374 /* only the parent has fasync state */
6376 event = event->parent;
6377 return &event->fasync;
6380 void perf_event_wakeup(struct perf_event *event)
6382 ring_buffer_wakeup(event);
6384 if (event->pending_kill) {
6385 kill_fasync(perf_event_fasync(event), SIGIO, event->pending_kill);
6386 event->pending_kill = 0;
6390 static void perf_sigtrap(struct perf_event *event)
6392 struct kernel_siginfo info;
6395 * We'd expect this to only occur if the irq_work is delayed and either
6396 * ctx->task or current has changed in the meantime. This can be the
6397 * case on architectures that do not implement arch_irq_work_raise().
6399 if (WARN_ON_ONCE(event->ctx->task != current))
6403 * perf_pending_event() can race with the task exiting.
6405 if (current->flags & PF_EXITING)
6408 clear_siginfo(&info);
6409 info.si_signo = SIGTRAP;
6410 info.si_code = TRAP_PERF;
6411 info.si_errno = event->attr.type;
6412 info.si_perf = event->attr.sig_data;
6413 info.si_addr = (void __user *)event->pending_addr;
6414 force_sig_info(&info);
6417 static void perf_pending_event_disable(struct perf_event *event)
6419 int cpu = READ_ONCE(event->pending_disable);
6424 if (cpu == smp_processor_id()) {
6425 WRITE_ONCE(event->pending_disable, -1);
6427 if (event->attr.sigtrap) {
6428 perf_sigtrap(event);
6429 atomic_set_release(&event->event_limit, 1); /* rearm event */
6433 perf_event_disable_local(event);
6440 * perf_event_disable_inatomic()
6441 * @pending_disable = CPU-A;
6445 * @pending_disable = -1;
6448 * perf_event_disable_inatomic()
6449 * @pending_disable = CPU-B;
6450 * irq_work_queue(); // FAILS
6453 * perf_pending_event()
6455 * But the event runs on CPU-B and wants disabling there.
6457 irq_work_queue_on(&event->pending, cpu);
6460 static void perf_pending_event(struct irq_work *entry)
6462 struct perf_event *event = container_of(entry, struct perf_event, pending);
6465 rctx = perf_swevent_get_recursion_context();
6467 * If we 'fail' here, that's OK, it means recursion is already disabled
6468 * and we won't recurse 'further'.
6471 perf_pending_event_disable(event);
6473 if (event->pending_wakeup) {
6474 event->pending_wakeup = 0;
6475 perf_event_wakeup(event);
6479 perf_swevent_put_recursion_context(rctx);
6483 * We assume there is only KVM supporting the callbacks.
6484 * Later on, we might change it to a list if there is
6485 * another virtualization implementation supporting the callbacks.
6487 struct perf_guest_info_callbacks *perf_guest_cbs;
6489 int perf_register_guest_info_callbacks(struct perf_guest_info_callbacks *cbs)
6491 perf_guest_cbs = cbs;
6494 EXPORT_SYMBOL_GPL(perf_register_guest_info_callbacks);
6496 int perf_unregister_guest_info_callbacks(struct perf_guest_info_callbacks *cbs)
6498 perf_guest_cbs = NULL;
6501 EXPORT_SYMBOL_GPL(perf_unregister_guest_info_callbacks);
6504 perf_output_sample_regs(struct perf_output_handle *handle,
6505 struct pt_regs *regs, u64 mask)
6508 DECLARE_BITMAP(_mask, 64);
6510 bitmap_from_u64(_mask, mask);
6511 for_each_set_bit(bit, _mask, sizeof(mask) * BITS_PER_BYTE) {
6514 val = perf_reg_value(regs, bit);
6515 perf_output_put(handle, val);
6519 static void perf_sample_regs_user(struct perf_regs *regs_user,
6520 struct pt_regs *regs)
6522 if (user_mode(regs)) {
6523 regs_user->abi = perf_reg_abi(current);
6524 regs_user->regs = regs;
6525 } else if (!(current->flags & PF_KTHREAD)) {
6526 perf_get_regs_user(regs_user, regs);
6528 regs_user->abi = PERF_SAMPLE_REGS_ABI_NONE;
6529 regs_user->regs = NULL;
6533 static void perf_sample_regs_intr(struct perf_regs *regs_intr,
6534 struct pt_regs *regs)
6536 regs_intr->regs = regs;
6537 regs_intr->abi = perf_reg_abi(current);
6542 * Get remaining task size from user stack pointer.
6544 * It'd be better to take stack vma map and limit this more
6545 * precisely, but there's no way to get it safely under interrupt,
6546 * so using TASK_SIZE as limit.
6548 static u64 perf_ustack_task_size(struct pt_regs *regs)
6550 unsigned long addr = perf_user_stack_pointer(regs);
6552 if (!addr || addr >= TASK_SIZE)
6555 return TASK_SIZE - addr;
6559 perf_sample_ustack_size(u16 stack_size, u16 header_size,
6560 struct pt_regs *regs)
6564 /* No regs, no stack pointer, no dump. */
6569 * Check if we fit in with the requested stack size into the:
6571 * If we don't, we limit the size to the TASK_SIZE.
6573 * - remaining sample size
6574 * If we don't, we customize the stack size to
6575 * fit in to the remaining sample size.
6578 task_size = min((u64) USHRT_MAX, perf_ustack_task_size(regs));
6579 stack_size = min(stack_size, (u16) task_size);
6581 /* Current header size plus static size and dynamic size. */
6582 header_size += 2 * sizeof(u64);
6584 /* Do we fit in with the current stack dump size? */
6585 if ((u16) (header_size + stack_size) < header_size) {
6587 * If we overflow the maximum size for the sample,
6588 * we customize the stack dump size to fit in.
6590 stack_size = USHRT_MAX - header_size - sizeof(u64);
6591 stack_size = round_up(stack_size, sizeof(u64));
6598 perf_output_sample_ustack(struct perf_output_handle *handle, u64 dump_size,
6599 struct pt_regs *regs)
6601 /* Case of a kernel thread, nothing to dump */
6604 perf_output_put(handle, size);
6614 * - the size requested by user or the best one we can fit
6615 * in to the sample max size
6617 * - user stack dump data
6619 * - the actual dumped size
6623 perf_output_put(handle, dump_size);
6626 sp = perf_user_stack_pointer(regs);
6627 fs = force_uaccess_begin();
6628 rem = __output_copy_user(handle, (void *) sp, dump_size);
6629 force_uaccess_end(fs);
6630 dyn_size = dump_size - rem;
6632 perf_output_skip(handle, rem);
6635 perf_output_put(handle, dyn_size);
6639 static unsigned long perf_prepare_sample_aux(struct perf_event *event,
6640 struct perf_sample_data *data,
6643 struct perf_event *sampler = event->aux_event;
6644 struct perf_buffer *rb;
6651 if (WARN_ON_ONCE(READ_ONCE(sampler->state) != PERF_EVENT_STATE_ACTIVE))
6654 if (WARN_ON_ONCE(READ_ONCE(sampler->oncpu) != smp_processor_id()))
6657 rb = ring_buffer_get(sampler->parent ? sampler->parent : sampler);
6662 * If this is an NMI hit inside sampling code, don't take
6663 * the sample. See also perf_aux_sample_output().
6665 if (READ_ONCE(rb->aux_in_sampling)) {
6668 size = min_t(size_t, size, perf_aux_size(rb));
6669 data->aux_size = ALIGN(size, sizeof(u64));
6671 ring_buffer_put(rb);
6674 return data->aux_size;
6677 long perf_pmu_snapshot_aux(struct perf_buffer *rb,
6678 struct perf_event *event,
6679 struct perf_output_handle *handle,
6682 unsigned long flags;
6686 * Normal ->start()/->stop() callbacks run in IRQ mode in scheduler
6687 * paths. If we start calling them in NMI context, they may race with
6688 * the IRQ ones, that is, for example, re-starting an event that's just
6689 * been stopped, which is why we're using a separate callback that
6690 * doesn't change the event state.
6692 * IRQs need to be disabled to prevent IPIs from racing with us.
6694 local_irq_save(flags);
6696 * Guard against NMI hits inside the critical section;
6697 * see also perf_prepare_sample_aux().
6699 WRITE_ONCE(rb->aux_in_sampling, 1);
6702 ret = event->pmu->snapshot_aux(event, handle, size);
6705 WRITE_ONCE(rb->aux_in_sampling, 0);
6706 local_irq_restore(flags);
6711 static void perf_aux_sample_output(struct perf_event *event,
6712 struct perf_output_handle *handle,
6713 struct perf_sample_data *data)
6715 struct perf_event *sampler = event->aux_event;
6716 struct perf_buffer *rb;
6720 if (WARN_ON_ONCE(!sampler || !data->aux_size))
6723 rb = ring_buffer_get(sampler->parent ? sampler->parent : sampler);
6727 size = perf_pmu_snapshot_aux(rb, sampler, handle, data->aux_size);
6730 * An error here means that perf_output_copy() failed (returned a
6731 * non-zero surplus that it didn't copy), which in its current
6732 * enlightened implementation is not possible. If that changes, we'd
6735 if (WARN_ON_ONCE(size < 0))
6739 * The pad comes from ALIGN()ing data->aux_size up to u64 in
6740 * perf_prepare_sample_aux(), so should not be more than that.
6742 pad = data->aux_size - size;
6743 if (WARN_ON_ONCE(pad >= sizeof(u64)))
6748 perf_output_copy(handle, &zero, pad);
6752 ring_buffer_put(rb);
6755 static void __perf_event_header__init_id(struct perf_event_header *header,
6756 struct perf_sample_data *data,
6757 struct perf_event *event)
6759 u64 sample_type = event->attr.sample_type;
6761 data->type = sample_type;
6762 header->size += event->id_header_size;
6764 if (sample_type & PERF_SAMPLE_TID) {
6765 /* namespace issues */
6766 data->tid_entry.pid = perf_event_pid(event, current);
6767 data->tid_entry.tid = perf_event_tid(event, current);
6770 if (sample_type & PERF_SAMPLE_TIME)
6771 data->time = perf_event_clock(event);
6773 if (sample_type & (PERF_SAMPLE_ID | PERF_SAMPLE_IDENTIFIER))
6774 data->id = primary_event_id(event);
6776 if (sample_type & PERF_SAMPLE_STREAM_ID)
6777 data->stream_id = event->id;
6779 if (sample_type & PERF_SAMPLE_CPU) {
6780 data->cpu_entry.cpu = raw_smp_processor_id();
6781 data->cpu_entry.reserved = 0;
6785 void perf_event_header__init_id(struct perf_event_header *header,
6786 struct perf_sample_data *data,
6787 struct perf_event *event)
6789 if (event->attr.sample_id_all)
6790 __perf_event_header__init_id(header, data, event);
6793 static void __perf_event__output_id_sample(struct perf_output_handle *handle,
6794 struct perf_sample_data *data)
6796 u64 sample_type = data->type;
6798 if (sample_type & PERF_SAMPLE_TID)
6799 perf_output_put(handle, data->tid_entry);
6801 if (sample_type & PERF_SAMPLE_TIME)
6802 perf_output_put(handle, data->time);
6804 if (sample_type & PERF_SAMPLE_ID)
6805 perf_output_put(handle, data->id);
6807 if (sample_type & PERF_SAMPLE_STREAM_ID)
6808 perf_output_put(handle, data->stream_id);
6810 if (sample_type & PERF_SAMPLE_CPU)
6811 perf_output_put(handle, data->cpu_entry);
6813 if (sample_type & PERF_SAMPLE_IDENTIFIER)
6814 perf_output_put(handle, data->id);
6817 void perf_event__output_id_sample(struct perf_event *event,
6818 struct perf_output_handle *handle,
6819 struct perf_sample_data *sample)
6821 if (event->attr.sample_id_all)
6822 __perf_event__output_id_sample(handle, sample);
6825 static void perf_output_read_one(struct perf_output_handle *handle,
6826 struct perf_event *event,
6827 u64 enabled, u64 running)
6829 u64 read_format = event->attr.read_format;
6833 values[n++] = perf_event_count(event);
6834 if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED) {
6835 values[n++] = enabled +
6836 atomic64_read(&event->child_total_time_enabled);
6838 if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING) {
6839 values[n++] = running +
6840 atomic64_read(&event->child_total_time_running);
6842 if (read_format & PERF_FORMAT_ID)
6843 values[n++] = primary_event_id(event);
6845 __output_copy(handle, values, n * sizeof(u64));
6848 static void perf_output_read_group(struct perf_output_handle *handle,
6849 struct perf_event *event,
6850 u64 enabled, u64 running)
6852 struct perf_event *leader = event->group_leader, *sub;
6853 u64 read_format = event->attr.read_format;
6857 values[n++] = 1 + leader->nr_siblings;
6859 if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED)
6860 values[n++] = enabled;
6862 if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING)
6863 values[n++] = running;
6865 if ((leader != event) &&
6866 (leader->state == PERF_EVENT_STATE_ACTIVE))
6867 leader->pmu->read(leader);
6869 values[n++] = perf_event_count(leader);
6870 if (read_format & PERF_FORMAT_ID)
6871 values[n++] = primary_event_id(leader);
6873 __output_copy(handle, values, n * sizeof(u64));
6875 for_each_sibling_event(sub, leader) {
6878 if ((sub != event) &&
6879 (sub->state == PERF_EVENT_STATE_ACTIVE))
6880 sub->pmu->read(sub);
6882 values[n++] = perf_event_count(sub);
6883 if (read_format & PERF_FORMAT_ID)
6884 values[n++] = primary_event_id(sub);
6886 __output_copy(handle, values, n * sizeof(u64));
6890 #define PERF_FORMAT_TOTAL_TIMES (PERF_FORMAT_TOTAL_TIME_ENABLED|\
6891 PERF_FORMAT_TOTAL_TIME_RUNNING)
6894 * XXX PERF_SAMPLE_READ vs inherited events seems difficult.
6896 * The problem is that its both hard and excessively expensive to iterate the
6897 * child list, not to mention that its impossible to IPI the children running
6898 * on another CPU, from interrupt/NMI context.
6900 static void perf_output_read(struct perf_output_handle *handle,
6901 struct perf_event *event)
6903 u64 enabled = 0, running = 0, now;
6904 u64 read_format = event->attr.read_format;
6907 * compute total_time_enabled, total_time_running
6908 * based on snapshot values taken when the event
6909 * was last scheduled in.
6911 * we cannot simply called update_context_time()
6912 * because of locking issue as we are called in
6915 if (read_format & PERF_FORMAT_TOTAL_TIMES)
6916 calc_timer_values(event, &now, &enabled, &running);
6918 if (event->attr.read_format & PERF_FORMAT_GROUP)
6919 perf_output_read_group(handle, event, enabled, running);
6921 perf_output_read_one(handle, event, enabled, running);
6924 static inline bool perf_sample_save_hw_index(struct perf_event *event)
6926 return event->attr.branch_sample_type & PERF_SAMPLE_BRANCH_HW_INDEX;
6929 void perf_output_sample(struct perf_output_handle *handle,
6930 struct perf_event_header *header,
6931 struct perf_sample_data *data,
6932 struct perf_event *event)
6934 u64 sample_type = data->type;
6936 perf_output_put(handle, *header);
6938 if (sample_type & PERF_SAMPLE_IDENTIFIER)
6939 perf_output_put(handle, data->id);
6941 if (sample_type & PERF_SAMPLE_IP)
6942 perf_output_put(handle, data->ip);
6944 if (sample_type & PERF_SAMPLE_TID)
6945 perf_output_put(handle, data->tid_entry);
6947 if (sample_type & PERF_SAMPLE_TIME)
6948 perf_output_put(handle, data->time);
6950 if (sample_type & PERF_SAMPLE_ADDR)
6951 perf_output_put(handle, data->addr);
6953 if (sample_type & PERF_SAMPLE_ID)
6954 perf_output_put(handle, data->id);
6956 if (sample_type & PERF_SAMPLE_STREAM_ID)
6957 perf_output_put(handle, data->stream_id);
6959 if (sample_type & PERF_SAMPLE_CPU)
6960 perf_output_put(handle, data->cpu_entry);
6962 if (sample_type & PERF_SAMPLE_PERIOD)
6963 perf_output_put(handle, data->period);
6965 if (sample_type & PERF_SAMPLE_READ)
6966 perf_output_read(handle, event);
6968 if (sample_type & PERF_SAMPLE_CALLCHAIN) {
6971 size += data->callchain->nr;
6972 size *= sizeof(u64);
6973 __output_copy(handle, data->callchain, size);
6976 if (sample_type & PERF_SAMPLE_RAW) {
6977 struct perf_raw_record *raw = data->raw;
6980 struct perf_raw_frag *frag = &raw->frag;
6982 perf_output_put(handle, raw->size);
6985 __output_custom(handle, frag->copy,
6986 frag->data, frag->size);
6988 __output_copy(handle, frag->data,
6991 if (perf_raw_frag_last(frag))
6996 __output_skip(handle, NULL, frag->pad);
7002 .size = sizeof(u32),
7005 perf_output_put(handle, raw);
7009 if (sample_type & PERF_SAMPLE_BRANCH_STACK) {
7010 if (data->br_stack) {
7013 size = data->br_stack->nr
7014 * sizeof(struct perf_branch_entry);
7016 perf_output_put(handle, data->br_stack->nr);
7017 if (perf_sample_save_hw_index(event))
7018 perf_output_put(handle, data->br_stack->hw_idx);
7019 perf_output_copy(handle, data->br_stack->entries, size);
7022 * we always store at least the value of nr
7025 perf_output_put(handle, nr);
7029 if (sample_type & PERF_SAMPLE_REGS_USER) {
7030 u64 abi = data->regs_user.abi;
7033 * If there are no regs to dump, notice it through
7034 * first u64 being zero (PERF_SAMPLE_REGS_ABI_NONE).
7036 perf_output_put(handle, abi);
7039 u64 mask = event->attr.sample_regs_user;
7040 perf_output_sample_regs(handle,
7041 data->regs_user.regs,
7046 if (sample_type & PERF_SAMPLE_STACK_USER) {
7047 perf_output_sample_ustack(handle,
7048 data->stack_user_size,
7049 data->regs_user.regs);
7052 if (sample_type & PERF_SAMPLE_WEIGHT_TYPE)
7053 perf_output_put(handle, data->weight.full);
7055 if (sample_type & PERF_SAMPLE_DATA_SRC)
7056 perf_output_put(handle, data->data_src.val);
7058 if (sample_type & PERF_SAMPLE_TRANSACTION)
7059 perf_output_put(handle, data->txn);
7061 if (sample_type & PERF_SAMPLE_REGS_INTR) {
7062 u64 abi = data->regs_intr.abi;
7064 * If there are no regs to dump, notice it through
7065 * first u64 being zero (PERF_SAMPLE_REGS_ABI_NONE).
7067 perf_output_put(handle, abi);
7070 u64 mask = event->attr.sample_regs_intr;
7072 perf_output_sample_regs(handle,
7073 data->regs_intr.regs,
7078 if (sample_type & PERF_SAMPLE_PHYS_ADDR)
7079 perf_output_put(handle, data->phys_addr);
7081 if (sample_type & PERF_SAMPLE_CGROUP)
7082 perf_output_put(handle, data->cgroup);
7084 if (sample_type & PERF_SAMPLE_DATA_PAGE_SIZE)
7085 perf_output_put(handle, data->data_page_size);
7087 if (sample_type & PERF_SAMPLE_CODE_PAGE_SIZE)
7088 perf_output_put(handle, data->code_page_size);
7090 if (sample_type & PERF_SAMPLE_AUX) {
7091 perf_output_put(handle, data->aux_size);
7094 perf_aux_sample_output(event, handle, data);
7097 if (!event->attr.watermark) {
7098 int wakeup_events = event->attr.wakeup_events;
7100 if (wakeup_events) {
7101 struct perf_buffer *rb = handle->rb;
7102 int events = local_inc_return(&rb->events);
7104 if (events >= wakeup_events) {
7105 local_sub(wakeup_events, &rb->events);
7106 local_inc(&rb->wakeup);
7112 static u64 perf_virt_to_phys(u64 virt)
7115 struct page *p = NULL;
7120 if (virt >= TASK_SIZE) {
7121 /* If it's vmalloc()d memory, leave phys_addr as 0 */
7122 if (virt_addr_valid((void *)(uintptr_t)virt) &&
7123 !(virt >= VMALLOC_START && virt < VMALLOC_END))
7124 phys_addr = (u64)virt_to_phys((void *)(uintptr_t)virt);
7127 * Walking the pages tables for user address.
7128 * Interrupts are disabled, so it prevents any tear down
7129 * of the page tables.
7130 * Try IRQ-safe get_user_page_fast_only first.
7131 * If failed, leave phys_addr as 0.
7133 if (current->mm != NULL) {
7134 pagefault_disable();
7135 if (get_user_page_fast_only(virt, 0, &p))
7136 phys_addr = page_to_phys(p) + virt % PAGE_SIZE;
7148 * Return the pagetable size of a given virtual address.
7150 static u64 perf_get_pgtable_size(struct mm_struct *mm, unsigned long addr)
7154 #ifdef CONFIG_HAVE_FAST_GUP
7161 pgdp = pgd_offset(mm, addr);
7162 pgd = READ_ONCE(*pgdp);
7167 return pgd_leaf_size(pgd);
7169 p4dp = p4d_offset_lockless(pgdp, pgd, addr);
7170 p4d = READ_ONCE(*p4dp);
7171 if (!p4d_present(p4d))
7175 return p4d_leaf_size(p4d);
7177 pudp = pud_offset_lockless(p4dp, p4d, addr);
7178 pud = READ_ONCE(*pudp);
7179 if (!pud_present(pud))
7183 return pud_leaf_size(pud);
7185 pmdp = pmd_offset_lockless(pudp, pud, addr);
7186 pmd = READ_ONCE(*pmdp);
7187 if (!pmd_present(pmd))
7191 return pmd_leaf_size(pmd);
7193 ptep = pte_offset_map(&pmd, addr);
7194 pte = ptep_get_lockless(ptep);
7195 if (pte_present(pte))
7196 size = pte_leaf_size(pte);
7198 #endif /* CONFIG_HAVE_FAST_GUP */
7203 static u64 perf_get_page_size(unsigned long addr)
7205 struct mm_struct *mm;
7206 unsigned long flags;
7213 * Software page-table walkers must disable IRQs,
7214 * which prevents any tear down of the page tables.
7216 local_irq_save(flags);
7221 * For kernel threads and the like, use init_mm so that
7222 * we can find kernel memory.
7227 size = perf_get_pgtable_size(mm, addr);
7229 local_irq_restore(flags);
7234 static struct perf_callchain_entry __empty_callchain = { .nr = 0, };
7236 struct perf_callchain_entry *
7237 perf_callchain(struct perf_event *event, struct pt_regs *regs)
7239 bool kernel = !event->attr.exclude_callchain_kernel;
7240 bool user = !event->attr.exclude_callchain_user;
7241 /* Disallow cross-task user callchains. */
7242 bool crosstask = event->ctx->task && event->ctx->task != current;
7243 const u32 max_stack = event->attr.sample_max_stack;
7244 struct perf_callchain_entry *callchain;
7246 if (!kernel && !user)
7247 return &__empty_callchain;
7249 callchain = get_perf_callchain(regs, 0, kernel, user,
7250 max_stack, crosstask, true);
7251 return callchain ?: &__empty_callchain;
7254 void perf_prepare_sample(struct perf_event_header *header,
7255 struct perf_sample_data *data,
7256 struct perf_event *event,
7257 struct pt_regs *regs)
7259 u64 sample_type = event->attr.sample_type;
7261 header->type = PERF_RECORD_SAMPLE;
7262 header->size = sizeof(*header) + event->header_size;
7265 header->misc |= perf_misc_flags(regs);
7267 __perf_event_header__init_id(header, data, event);
7269 if (sample_type & (PERF_SAMPLE_IP | PERF_SAMPLE_CODE_PAGE_SIZE))
7270 data->ip = perf_instruction_pointer(regs);
7272 if (sample_type & PERF_SAMPLE_CALLCHAIN) {
7275 if (!(sample_type & __PERF_SAMPLE_CALLCHAIN_EARLY))
7276 data->callchain = perf_callchain(event, regs);
7278 size += data->callchain->nr;
7280 header->size += size * sizeof(u64);
7283 if (sample_type & PERF_SAMPLE_RAW) {
7284 struct perf_raw_record *raw = data->raw;
7288 struct perf_raw_frag *frag = &raw->frag;
7293 if (perf_raw_frag_last(frag))
7298 size = round_up(sum + sizeof(u32), sizeof(u64));
7299 raw->size = size - sizeof(u32);
7300 frag->pad = raw->size - sum;
7305 header->size += size;
7308 if (sample_type & PERF_SAMPLE_BRANCH_STACK) {
7309 int size = sizeof(u64); /* nr */
7310 if (data->br_stack) {
7311 if (perf_sample_save_hw_index(event))
7312 size += sizeof(u64);
7314 size += data->br_stack->nr
7315 * sizeof(struct perf_branch_entry);
7317 header->size += size;
7320 if (sample_type & (PERF_SAMPLE_REGS_USER | PERF_SAMPLE_STACK_USER))
7321 perf_sample_regs_user(&data->regs_user, regs);
7323 if (sample_type & PERF_SAMPLE_REGS_USER) {
7324 /* regs dump ABI info */
7325 int size = sizeof(u64);
7327 if (data->regs_user.regs) {
7328 u64 mask = event->attr.sample_regs_user;
7329 size += hweight64(mask) * sizeof(u64);
7332 header->size += size;
7335 if (sample_type & PERF_SAMPLE_STACK_USER) {
7337 * Either we need PERF_SAMPLE_STACK_USER bit to be always
7338 * processed as the last one or have additional check added
7339 * in case new sample type is added, because we could eat
7340 * up the rest of the sample size.
7342 u16 stack_size = event->attr.sample_stack_user;
7343 u16 size = sizeof(u64);
7345 stack_size = perf_sample_ustack_size(stack_size, header->size,
7346 data->regs_user.regs);
7349 * If there is something to dump, add space for the dump
7350 * itself and for the field that tells the dynamic size,
7351 * which is how many have been actually dumped.
7354 size += sizeof(u64) + stack_size;
7356 data->stack_user_size = stack_size;
7357 header->size += size;
7360 if (sample_type & PERF_SAMPLE_REGS_INTR) {
7361 /* regs dump ABI info */
7362 int size = sizeof(u64);
7364 perf_sample_regs_intr(&data->regs_intr, regs);
7366 if (data->regs_intr.regs) {
7367 u64 mask = event->attr.sample_regs_intr;
7369 size += hweight64(mask) * sizeof(u64);
7372 header->size += size;
7375 if (sample_type & PERF_SAMPLE_PHYS_ADDR)
7376 data->phys_addr = perf_virt_to_phys(data->addr);
7378 #ifdef CONFIG_CGROUP_PERF
7379 if (sample_type & PERF_SAMPLE_CGROUP) {
7380 struct cgroup *cgrp;
7382 /* protected by RCU */
7383 cgrp = task_css_check(current, perf_event_cgrp_id, 1)->cgroup;
7384 data->cgroup = cgroup_id(cgrp);
7389 * PERF_DATA_PAGE_SIZE requires PERF_SAMPLE_ADDR. If the user doesn't
7390 * require PERF_SAMPLE_ADDR, kernel implicitly retrieve the data->addr,
7391 * but the value will not dump to the userspace.
7393 if (sample_type & PERF_SAMPLE_DATA_PAGE_SIZE)
7394 data->data_page_size = perf_get_page_size(data->addr);
7396 if (sample_type & PERF_SAMPLE_CODE_PAGE_SIZE)
7397 data->code_page_size = perf_get_page_size(data->ip);
7399 if (sample_type & PERF_SAMPLE_AUX) {
7402 header->size += sizeof(u64); /* size */
7405 * Given the 16bit nature of header::size, an AUX sample can
7406 * easily overflow it, what with all the preceding sample bits.
7407 * Make sure this doesn't happen by using up to U16_MAX bytes
7408 * per sample in total (rounded down to 8 byte boundary).
7410 size = min_t(size_t, U16_MAX - header->size,
7411 event->attr.aux_sample_size);
7412 size = rounddown(size, 8);
7413 size = perf_prepare_sample_aux(event, data, size);
7415 WARN_ON_ONCE(size + header->size > U16_MAX);
7416 header->size += size;
7419 * If you're adding more sample types here, you likely need to do
7420 * something about the overflowing header::size, like repurpose the
7421 * lowest 3 bits of size, which should be always zero at the moment.
7422 * This raises a more important question, do we really need 512k sized
7423 * samples and why, so good argumentation is in order for whatever you
7426 WARN_ON_ONCE(header->size & 7);
7429 static __always_inline int
7430 __perf_event_output(struct perf_event *event,
7431 struct perf_sample_data *data,
7432 struct pt_regs *regs,
7433 int (*output_begin)(struct perf_output_handle *,
7434 struct perf_sample_data *,
7435 struct perf_event *,
7438 struct perf_output_handle handle;
7439 struct perf_event_header header;
7442 /* protect the callchain buffers */
7445 perf_prepare_sample(&header, data, event, regs);
7447 err = output_begin(&handle, data, event, header.size);
7451 perf_output_sample(&handle, &header, data, event);
7453 perf_output_end(&handle);
7461 perf_event_output_forward(struct perf_event *event,
7462 struct perf_sample_data *data,
7463 struct pt_regs *regs)
7465 __perf_event_output(event, data, regs, perf_output_begin_forward);
7469 perf_event_output_backward(struct perf_event *event,
7470 struct perf_sample_data *data,
7471 struct pt_regs *regs)
7473 __perf_event_output(event, data, regs, perf_output_begin_backward);
7477 perf_event_output(struct perf_event *event,
7478 struct perf_sample_data *data,
7479 struct pt_regs *regs)
7481 return __perf_event_output(event, data, regs, perf_output_begin);
7488 struct perf_read_event {
7489 struct perf_event_header header;
7496 perf_event_read_event(struct perf_event *event,
7497 struct task_struct *task)
7499 struct perf_output_handle handle;
7500 struct perf_sample_data sample;
7501 struct perf_read_event read_event = {
7503 .type = PERF_RECORD_READ,
7505 .size = sizeof(read_event) + event->read_size,
7507 .pid = perf_event_pid(event, task),
7508 .tid = perf_event_tid(event, task),
7512 perf_event_header__init_id(&read_event.header, &sample, event);
7513 ret = perf_output_begin(&handle, &sample, event, read_event.header.size);
7517 perf_output_put(&handle, read_event);
7518 perf_output_read(&handle, event);
7519 perf_event__output_id_sample(event, &handle, &sample);
7521 perf_output_end(&handle);
7524 typedef void (perf_iterate_f)(struct perf_event *event, void *data);
7527 perf_iterate_ctx(struct perf_event_context *ctx,
7528 perf_iterate_f output,
7529 void *data, bool all)
7531 struct perf_event *event;
7533 list_for_each_entry_rcu(event, &ctx->event_list, event_entry) {
7535 if (event->state < PERF_EVENT_STATE_INACTIVE)
7537 if (!event_filter_match(event))
7541 output(event, data);
7545 static void perf_iterate_sb_cpu(perf_iterate_f output, void *data)
7547 struct pmu_event_list *pel = this_cpu_ptr(&pmu_sb_events);
7548 struct perf_event *event;
7550 list_for_each_entry_rcu(event, &pel->list, sb_list) {
7552 * Skip events that are not fully formed yet; ensure that
7553 * if we observe event->ctx, both event and ctx will be
7554 * complete enough. See perf_install_in_context().
7556 if (!smp_load_acquire(&event->ctx))
7559 if (event->state < PERF_EVENT_STATE_INACTIVE)
7561 if (!event_filter_match(event))
7563 output(event, data);
7568 * Iterate all events that need to receive side-band events.
7570 * For new callers; ensure that account_pmu_sb_event() includes
7571 * your event, otherwise it might not get delivered.
7574 perf_iterate_sb(perf_iterate_f output, void *data,
7575 struct perf_event_context *task_ctx)
7577 struct perf_event_context *ctx;
7584 * If we have task_ctx != NULL we only notify the task context itself.
7585 * The task_ctx is set only for EXIT events before releasing task
7589 perf_iterate_ctx(task_ctx, output, data, false);
7593 perf_iterate_sb_cpu(output, data);
7595 for_each_task_context_nr(ctxn) {
7596 ctx = rcu_dereference(current->perf_event_ctxp[ctxn]);
7598 perf_iterate_ctx(ctx, output, data, false);
7606 * Clear all file-based filters at exec, they'll have to be
7607 * re-instated when/if these objects are mmapped again.
7609 static void perf_event_addr_filters_exec(struct perf_event *event, void *data)
7611 struct perf_addr_filters_head *ifh = perf_event_addr_filters(event);
7612 struct perf_addr_filter *filter;
7613 unsigned int restart = 0, count = 0;
7614 unsigned long flags;
7616 if (!has_addr_filter(event))
7619 raw_spin_lock_irqsave(&ifh->lock, flags);
7620 list_for_each_entry(filter, &ifh->list, entry) {
7621 if (filter->path.dentry) {
7622 event->addr_filter_ranges[count].start = 0;
7623 event->addr_filter_ranges[count].size = 0;
7631 event->addr_filters_gen++;
7632 raw_spin_unlock_irqrestore(&ifh->lock, flags);
7635 perf_event_stop(event, 1);
7638 void perf_event_exec(void)
7640 struct perf_event_context *ctx;
7643 for_each_task_context_nr(ctxn) {
7644 perf_event_enable_on_exec(ctxn);
7645 perf_event_remove_on_exec(ctxn);
7648 ctx = rcu_dereference(current->perf_event_ctxp[ctxn]);
7650 perf_iterate_ctx(ctx, perf_event_addr_filters_exec,
7657 struct remote_output {
7658 struct perf_buffer *rb;
7662 static void __perf_event_output_stop(struct perf_event *event, void *data)
7664 struct perf_event *parent = event->parent;
7665 struct remote_output *ro = data;
7666 struct perf_buffer *rb = ro->rb;
7667 struct stop_event_data sd = {
7671 if (!has_aux(event))
7678 * In case of inheritance, it will be the parent that links to the
7679 * ring-buffer, but it will be the child that's actually using it.
7681 * We are using event::rb to determine if the event should be stopped,
7682 * however this may race with ring_buffer_attach() (through set_output),
7683 * which will make us skip the event that actually needs to be stopped.
7684 * So ring_buffer_attach() has to stop an aux event before re-assigning
7687 if (rcu_dereference(parent->rb) == rb)
7688 ro->err = __perf_event_stop(&sd);
7691 static int __perf_pmu_output_stop(void *info)
7693 struct perf_event *event = info;
7694 struct pmu *pmu = event->ctx->pmu;
7695 struct perf_cpu_context *cpuctx = this_cpu_ptr(pmu->pmu_cpu_context);
7696 struct remote_output ro = {
7701 perf_iterate_ctx(&cpuctx->ctx, __perf_event_output_stop, &ro, false);
7702 if (cpuctx->task_ctx)
7703 perf_iterate_ctx(cpuctx->task_ctx, __perf_event_output_stop,
7710 static void perf_pmu_output_stop(struct perf_event *event)
7712 struct perf_event *iter;
7717 list_for_each_entry_rcu(iter, &event->rb->event_list, rb_entry) {
7719 * For per-CPU events, we need to make sure that neither they
7720 * nor their children are running; for cpu==-1 events it's
7721 * sufficient to stop the event itself if it's active, since
7722 * it can't have children.
7726 cpu = READ_ONCE(iter->oncpu);
7731 err = cpu_function_call(cpu, __perf_pmu_output_stop, event);
7732 if (err == -EAGAIN) {
7741 * task tracking -- fork/exit
7743 * enabled by: attr.comm | attr.mmap | attr.mmap2 | attr.mmap_data | attr.task
7746 struct perf_task_event {
7747 struct task_struct *task;
7748 struct perf_event_context *task_ctx;
7751 struct perf_event_header header;
7761 static int perf_event_task_match(struct perf_event *event)
7763 return event->attr.comm || event->attr.mmap ||
7764 event->attr.mmap2 || event->attr.mmap_data ||
7768 static void perf_event_task_output(struct perf_event *event,
7771 struct perf_task_event *task_event = data;
7772 struct perf_output_handle handle;
7773 struct perf_sample_data sample;
7774 struct task_struct *task = task_event->task;
7775 int ret, size = task_event->event_id.header.size;
7777 if (!perf_event_task_match(event))
7780 perf_event_header__init_id(&task_event->event_id.header, &sample, event);
7782 ret = perf_output_begin(&handle, &sample, event,
7783 task_event->event_id.header.size);
7787 task_event->event_id.pid = perf_event_pid(event, task);
7788 task_event->event_id.tid = perf_event_tid(event, task);
7790 if (task_event->event_id.header.type == PERF_RECORD_EXIT) {
7791 task_event->event_id.ppid = perf_event_pid(event,
7793 task_event->event_id.ptid = perf_event_pid(event,
7795 } else { /* PERF_RECORD_FORK */
7796 task_event->event_id.ppid = perf_event_pid(event, current);
7797 task_event->event_id.ptid = perf_event_tid(event, current);
7800 task_event->event_id.time = perf_event_clock(event);
7802 perf_output_put(&handle, task_event->event_id);
7804 perf_event__output_id_sample(event, &handle, &sample);
7806 perf_output_end(&handle);
7808 task_event->event_id.header.size = size;
7811 static void perf_event_task(struct task_struct *task,
7812 struct perf_event_context *task_ctx,
7815 struct perf_task_event task_event;
7817 if (!atomic_read(&nr_comm_events) &&
7818 !atomic_read(&nr_mmap_events) &&
7819 !atomic_read(&nr_task_events))
7822 task_event = (struct perf_task_event){
7824 .task_ctx = task_ctx,
7827 .type = new ? PERF_RECORD_FORK : PERF_RECORD_EXIT,
7829 .size = sizeof(task_event.event_id),
7839 perf_iterate_sb(perf_event_task_output,
7844 void perf_event_fork(struct task_struct *task)
7846 perf_event_task(task, NULL, 1);
7847 perf_event_namespaces(task);
7854 struct perf_comm_event {
7855 struct task_struct *task;
7860 struct perf_event_header header;
7867 static int perf_event_comm_match(struct perf_event *event)
7869 return event->attr.comm;
7872 static void perf_event_comm_output(struct perf_event *event,
7875 struct perf_comm_event *comm_event = data;
7876 struct perf_output_handle handle;
7877 struct perf_sample_data sample;
7878 int size = comm_event->event_id.header.size;
7881 if (!perf_event_comm_match(event))
7884 perf_event_header__init_id(&comm_event->event_id.header, &sample, event);
7885 ret = perf_output_begin(&handle, &sample, event,
7886 comm_event->event_id.header.size);
7891 comm_event->event_id.pid = perf_event_pid(event, comm_event->task);
7892 comm_event->event_id.tid = perf_event_tid(event, comm_event->task);
7894 perf_output_put(&handle, comm_event->event_id);
7895 __output_copy(&handle, comm_event->comm,
7896 comm_event->comm_size);
7898 perf_event__output_id_sample(event, &handle, &sample);
7900 perf_output_end(&handle);
7902 comm_event->event_id.header.size = size;
7905 static void perf_event_comm_event(struct perf_comm_event *comm_event)
7907 char comm[TASK_COMM_LEN];
7910 memset(comm, 0, sizeof(comm));
7911 strlcpy(comm, comm_event->task->comm, sizeof(comm));
7912 size = ALIGN(strlen(comm)+1, sizeof(u64));
7914 comm_event->comm = comm;
7915 comm_event->comm_size = size;
7917 comm_event->event_id.header.size = sizeof(comm_event->event_id) + size;
7919 perf_iterate_sb(perf_event_comm_output,
7924 void perf_event_comm(struct task_struct *task, bool exec)
7926 struct perf_comm_event comm_event;
7928 if (!atomic_read(&nr_comm_events))
7931 comm_event = (struct perf_comm_event){
7937 .type = PERF_RECORD_COMM,
7938 .misc = exec ? PERF_RECORD_MISC_COMM_EXEC : 0,
7946 perf_event_comm_event(&comm_event);
7950 * namespaces tracking
7953 struct perf_namespaces_event {
7954 struct task_struct *task;
7957 struct perf_event_header header;
7962 struct perf_ns_link_info link_info[NR_NAMESPACES];
7966 static int perf_event_namespaces_match(struct perf_event *event)
7968 return event->attr.namespaces;
7971 static void perf_event_namespaces_output(struct perf_event *event,
7974 struct perf_namespaces_event *namespaces_event = data;
7975 struct perf_output_handle handle;
7976 struct perf_sample_data sample;
7977 u16 header_size = namespaces_event->event_id.header.size;
7980 if (!perf_event_namespaces_match(event))
7983 perf_event_header__init_id(&namespaces_event->event_id.header,
7985 ret = perf_output_begin(&handle, &sample, event,
7986 namespaces_event->event_id.header.size);
7990 namespaces_event->event_id.pid = perf_event_pid(event,
7991 namespaces_event->task);
7992 namespaces_event->event_id.tid = perf_event_tid(event,
7993 namespaces_event->task);
7995 perf_output_put(&handle, namespaces_event->event_id);
7997 perf_event__output_id_sample(event, &handle, &sample);
7999 perf_output_end(&handle);
8001 namespaces_event->event_id.header.size = header_size;
8004 static void perf_fill_ns_link_info(struct perf_ns_link_info *ns_link_info,
8005 struct task_struct *task,
8006 const struct proc_ns_operations *ns_ops)
8008 struct path ns_path;
8009 struct inode *ns_inode;
8012 error = ns_get_path(&ns_path, task, ns_ops);
8014 ns_inode = ns_path.dentry->d_inode;
8015 ns_link_info->dev = new_encode_dev(ns_inode->i_sb->s_dev);
8016 ns_link_info->ino = ns_inode->i_ino;
8021 void perf_event_namespaces(struct task_struct *task)
8023 struct perf_namespaces_event namespaces_event;
8024 struct perf_ns_link_info *ns_link_info;
8026 if (!atomic_read(&nr_namespaces_events))
8029 namespaces_event = (struct perf_namespaces_event){
8033 .type = PERF_RECORD_NAMESPACES,
8035 .size = sizeof(namespaces_event.event_id),
8039 .nr_namespaces = NR_NAMESPACES,
8040 /* .link_info[NR_NAMESPACES] */
8044 ns_link_info = namespaces_event.event_id.link_info;
8046 perf_fill_ns_link_info(&ns_link_info[MNT_NS_INDEX],
8047 task, &mntns_operations);
8049 #ifdef CONFIG_USER_NS
8050 perf_fill_ns_link_info(&ns_link_info[USER_NS_INDEX],
8051 task, &userns_operations);
8053 #ifdef CONFIG_NET_NS
8054 perf_fill_ns_link_info(&ns_link_info[NET_NS_INDEX],
8055 task, &netns_operations);
8057 #ifdef CONFIG_UTS_NS
8058 perf_fill_ns_link_info(&ns_link_info[UTS_NS_INDEX],
8059 task, &utsns_operations);
8061 #ifdef CONFIG_IPC_NS
8062 perf_fill_ns_link_info(&ns_link_info[IPC_NS_INDEX],
8063 task, &ipcns_operations);
8065 #ifdef CONFIG_PID_NS
8066 perf_fill_ns_link_info(&ns_link_info[PID_NS_INDEX],
8067 task, &pidns_operations);
8069 #ifdef CONFIG_CGROUPS
8070 perf_fill_ns_link_info(&ns_link_info[CGROUP_NS_INDEX],
8071 task, &cgroupns_operations);
8074 perf_iterate_sb(perf_event_namespaces_output,
8082 #ifdef CONFIG_CGROUP_PERF
8084 struct perf_cgroup_event {
8088 struct perf_event_header header;
8094 static int perf_event_cgroup_match(struct perf_event *event)
8096 return event->attr.cgroup;
8099 static void perf_event_cgroup_output(struct perf_event *event, void *data)
8101 struct perf_cgroup_event *cgroup_event = data;
8102 struct perf_output_handle handle;
8103 struct perf_sample_data sample;
8104 u16 header_size = cgroup_event->event_id.header.size;
8107 if (!perf_event_cgroup_match(event))
8110 perf_event_header__init_id(&cgroup_event->event_id.header,
8112 ret = perf_output_begin(&handle, &sample, event,
8113 cgroup_event->event_id.header.size);
8117 perf_output_put(&handle, cgroup_event->event_id);
8118 __output_copy(&handle, cgroup_event->path, cgroup_event->path_size);
8120 perf_event__output_id_sample(event, &handle, &sample);
8122 perf_output_end(&handle);
8124 cgroup_event->event_id.header.size = header_size;
8127 static void perf_event_cgroup(struct cgroup *cgrp)
8129 struct perf_cgroup_event cgroup_event;
8130 char path_enomem[16] = "//enomem";
8134 if (!atomic_read(&nr_cgroup_events))
8137 cgroup_event = (struct perf_cgroup_event){
8140 .type = PERF_RECORD_CGROUP,
8142 .size = sizeof(cgroup_event.event_id),
8144 .id = cgroup_id(cgrp),
8148 pathname = kmalloc(PATH_MAX, GFP_KERNEL);
8149 if (pathname == NULL) {
8150 cgroup_event.path = path_enomem;
8152 /* just to be sure to have enough space for alignment */
8153 cgroup_path(cgrp, pathname, PATH_MAX - sizeof(u64));
8154 cgroup_event.path = pathname;
8158 * Since our buffer works in 8 byte units we need to align our string
8159 * size to a multiple of 8. However, we must guarantee the tail end is
8160 * zero'd out to avoid leaking random bits to userspace.
8162 size = strlen(cgroup_event.path) + 1;
8163 while (!IS_ALIGNED(size, sizeof(u64)))
8164 cgroup_event.path[size++] = '\0';
8166 cgroup_event.event_id.header.size += size;
8167 cgroup_event.path_size = size;
8169 perf_iterate_sb(perf_event_cgroup_output,
8182 struct perf_mmap_event {
8183 struct vm_area_struct *vma;
8185 const char *file_name;
8191 u8 build_id[BUILD_ID_SIZE_MAX];
8195 struct perf_event_header header;
8205 static int perf_event_mmap_match(struct perf_event *event,
8208 struct perf_mmap_event *mmap_event = data;
8209 struct vm_area_struct *vma = mmap_event->vma;
8210 int executable = vma->vm_flags & VM_EXEC;
8212 return (!executable && event->attr.mmap_data) ||
8213 (executable && (event->attr.mmap || event->attr.mmap2));
8216 static void perf_event_mmap_output(struct perf_event *event,
8219 struct perf_mmap_event *mmap_event = data;
8220 struct perf_output_handle handle;
8221 struct perf_sample_data sample;
8222 int size = mmap_event->event_id.header.size;
8223 u32 type = mmap_event->event_id.header.type;
8227 if (!perf_event_mmap_match(event, data))
8230 if (event->attr.mmap2) {
8231 mmap_event->event_id.header.type = PERF_RECORD_MMAP2;
8232 mmap_event->event_id.header.size += sizeof(mmap_event->maj);
8233 mmap_event->event_id.header.size += sizeof(mmap_event->min);
8234 mmap_event->event_id.header.size += sizeof(mmap_event->ino);
8235 mmap_event->event_id.header.size += sizeof(mmap_event->ino_generation);
8236 mmap_event->event_id.header.size += sizeof(mmap_event->prot);
8237 mmap_event->event_id.header.size += sizeof(mmap_event->flags);
8240 perf_event_header__init_id(&mmap_event->event_id.header, &sample, event);
8241 ret = perf_output_begin(&handle, &sample, event,
8242 mmap_event->event_id.header.size);
8246 mmap_event->event_id.pid = perf_event_pid(event, current);
8247 mmap_event->event_id.tid = perf_event_tid(event, current);
8249 use_build_id = event->attr.build_id && mmap_event->build_id_size;
8251 if (event->attr.mmap2 && use_build_id)
8252 mmap_event->event_id.header.misc |= PERF_RECORD_MISC_MMAP_BUILD_ID;
8254 perf_output_put(&handle, mmap_event->event_id);
8256 if (event->attr.mmap2) {
8258 u8 size[4] = { (u8) mmap_event->build_id_size, 0, 0, 0 };
8260 __output_copy(&handle, size, 4);
8261 __output_copy(&handle, mmap_event->build_id, BUILD_ID_SIZE_MAX);
8263 perf_output_put(&handle, mmap_event->maj);
8264 perf_output_put(&handle, mmap_event->min);
8265 perf_output_put(&handle, mmap_event->ino);
8266 perf_output_put(&handle, mmap_event->ino_generation);
8268 perf_output_put(&handle, mmap_event->prot);
8269 perf_output_put(&handle, mmap_event->flags);
8272 __output_copy(&handle, mmap_event->file_name,
8273 mmap_event->file_size);
8275 perf_event__output_id_sample(event, &handle, &sample);
8277 perf_output_end(&handle);
8279 mmap_event->event_id.header.size = size;
8280 mmap_event->event_id.header.type = type;
8283 static void perf_event_mmap_event(struct perf_mmap_event *mmap_event)
8285 struct vm_area_struct *vma = mmap_event->vma;
8286 struct file *file = vma->vm_file;
8287 int maj = 0, min = 0;
8288 u64 ino = 0, gen = 0;
8289 u32 prot = 0, flags = 0;
8295 if (vma->vm_flags & VM_READ)
8297 if (vma->vm_flags & VM_WRITE)
8299 if (vma->vm_flags & VM_EXEC)
8302 if (vma->vm_flags & VM_MAYSHARE)
8305 flags = MAP_PRIVATE;
8307 if (vma->vm_flags & VM_DENYWRITE)
8308 flags |= MAP_DENYWRITE;
8309 if (vma->vm_flags & VM_MAYEXEC)
8310 flags |= MAP_EXECUTABLE;
8311 if (vma->vm_flags & VM_LOCKED)
8312 flags |= MAP_LOCKED;
8313 if (is_vm_hugetlb_page(vma))
8314 flags |= MAP_HUGETLB;
8317 struct inode *inode;
8320 buf = kmalloc(PATH_MAX, GFP_KERNEL);
8326 * d_path() works from the end of the rb backwards, so we
8327 * need to add enough zero bytes after the string to handle
8328 * the 64bit alignment we do later.
8330 name = file_path(file, buf, PATH_MAX - sizeof(u64));
8335 inode = file_inode(vma->vm_file);
8336 dev = inode->i_sb->s_dev;
8338 gen = inode->i_generation;
8344 if (vma->vm_ops && vma->vm_ops->name) {
8345 name = (char *) vma->vm_ops->name(vma);
8350 name = (char *)arch_vma_name(vma);
8354 if (vma->vm_start <= vma->vm_mm->start_brk &&
8355 vma->vm_end >= vma->vm_mm->brk) {
8359 if (vma->vm_start <= vma->vm_mm->start_stack &&
8360 vma->vm_end >= vma->vm_mm->start_stack) {
8370 strlcpy(tmp, name, sizeof(tmp));
8374 * Since our buffer works in 8 byte units we need to align our string
8375 * size to a multiple of 8. However, we must guarantee the tail end is
8376 * zero'd out to avoid leaking random bits to userspace.
8378 size = strlen(name)+1;
8379 while (!IS_ALIGNED(size, sizeof(u64)))
8380 name[size++] = '\0';
8382 mmap_event->file_name = name;
8383 mmap_event->file_size = size;
8384 mmap_event->maj = maj;
8385 mmap_event->min = min;
8386 mmap_event->ino = ino;
8387 mmap_event->ino_generation = gen;
8388 mmap_event->prot = prot;
8389 mmap_event->flags = flags;
8391 if (!(vma->vm_flags & VM_EXEC))
8392 mmap_event->event_id.header.misc |= PERF_RECORD_MISC_MMAP_DATA;
8394 mmap_event->event_id.header.size = sizeof(mmap_event->event_id) + size;
8396 if (atomic_read(&nr_build_id_events))
8397 build_id_parse(vma, mmap_event->build_id, &mmap_event->build_id_size);
8399 perf_iterate_sb(perf_event_mmap_output,
8407 * Check whether inode and address range match filter criteria.
8409 static bool perf_addr_filter_match(struct perf_addr_filter *filter,
8410 struct file *file, unsigned long offset,
8413 /* d_inode(NULL) won't be equal to any mapped user-space file */
8414 if (!filter->path.dentry)
8417 if (d_inode(filter->path.dentry) != file_inode(file))
8420 if (filter->offset > offset + size)
8423 if (filter->offset + filter->size < offset)
8429 static bool perf_addr_filter_vma_adjust(struct perf_addr_filter *filter,
8430 struct vm_area_struct *vma,
8431 struct perf_addr_filter_range *fr)
8433 unsigned long vma_size = vma->vm_end - vma->vm_start;
8434 unsigned long off = vma->vm_pgoff << PAGE_SHIFT;
8435 struct file *file = vma->vm_file;
8437 if (!perf_addr_filter_match(filter, file, off, vma_size))
8440 if (filter->offset < off) {
8441 fr->start = vma->vm_start;
8442 fr->size = min(vma_size, filter->size - (off - filter->offset));
8444 fr->start = vma->vm_start + filter->offset - off;
8445 fr->size = min(vma->vm_end - fr->start, filter->size);
8451 static void __perf_addr_filters_adjust(struct perf_event *event, void *data)
8453 struct perf_addr_filters_head *ifh = perf_event_addr_filters(event);
8454 struct vm_area_struct *vma = data;
8455 struct perf_addr_filter *filter;
8456 unsigned int restart = 0, count = 0;
8457 unsigned long flags;
8459 if (!has_addr_filter(event))
8465 raw_spin_lock_irqsave(&ifh->lock, flags);
8466 list_for_each_entry(filter, &ifh->list, entry) {
8467 if (perf_addr_filter_vma_adjust(filter, vma,
8468 &event->addr_filter_ranges[count]))
8475 event->addr_filters_gen++;
8476 raw_spin_unlock_irqrestore(&ifh->lock, flags);
8479 perf_event_stop(event, 1);
8483 * Adjust all task's events' filters to the new vma
8485 static void perf_addr_filters_adjust(struct vm_area_struct *vma)
8487 struct perf_event_context *ctx;
8491 * Data tracing isn't supported yet and as such there is no need
8492 * to keep track of anything that isn't related to executable code:
8494 if (!(vma->vm_flags & VM_EXEC))
8498 for_each_task_context_nr(ctxn) {
8499 ctx = rcu_dereference(current->perf_event_ctxp[ctxn]);
8503 perf_iterate_ctx(ctx, __perf_addr_filters_adjust, vma, true);
8508 void perf_event_mmap(struct vm_area_struct *vma)
8510 struct perf_mmap_event mmap_event;
8512 if (!atomic_read(&nr_mmap_events))
8515 mmap_event = (struct perf_mmap_event){
8521 .type = PERF_RECORD_MMAP,
8522 .misc = PERF_RECORD_MISC_USER,
8527 .start = vma->vm_start,
8528 .len = vma->vm_end - vma->vm_start,
8529 .pgoff = (u64)vma->vm_pgoff << PAGE_SHIFT,
8531 /* .maj (attr_mmap2 only) */
8532 /* .min (attr_mmap2 only) */
8533 /* .ino (attr_mmap2 only) */
8534 /* .ino_generation (attr_mmap2 only) */
8535 /* .prot (attr_mmap2 only) */
8536 /* .flags (attr_mmap2 only) */
8539 perf_addr_filters_adjust(vma);
8540 perf_event_mmap_event(&mmap_event);
8543 void perf_event_aux_event(struct perf_event *event, unsigned long head,
8544 unsigned long size, u64 flags)
8546 struct perf_output_handle handle;
8547 struct perf_sample_data sample;
8548 struct perf_aux_event {
8549 struct perf_event_header header;
8555 .type = PERF_RECORD_AUX,
8557 .size = sizeof(rec),
8565 perf_event_header__init_id(&rec.header, &sample, event);
8566 ret = perf_output_begin(&handle, &sample, event, rec.header.size);
8571 perf_output_put(&handle, rec);
8572 perf_event__output_id_sample(event, &handle, &sample);
8574 perf_output_end(&handle);
8578 * Lost/dropped samples logging
8580 void perf_log_lost_samples(struct perf_event *event, u64 lost)
8582 struct perf_output_handle handle;
8583 struct perf_sample_data sample;
8587 struct perf_event_header header;
8589 } lost_samples_event = {
8591 .type = PERF_RECORD_LOST_SAMPLES,
8593 .size = sizeof(lost_samples_event),
8598 perf_event_header__init_id(&lost_samples_event.header, &sample, event);
8600 ret = perf_output_begin(&handle, &sample, event,
8601 lost_samples_event.header.size);
8605 perf_output_put(&handle, lost_samples_event);
8606 perf_event__output_id_sample(event, &handle, &sample);
8607 perf_output_end(&handle);
8611 * context_switch tracking
8614 struct perf_switch_event {
8615 struct task_struct *task;
8616 struct task_struct *next_prev;
8619 struct perf_event_header header;
8625 static int perf_event_switch_match(struct perf_event *event)
8627 return event->attr.context_switch;
8630 static void perf_event_switch_output(struct perf_event *event, void *data)
8632 struct perf_switch_event *se = data;
8633 struct perf_output_handle handle;
8634 struct perf_sample_data sample;
8637 if (!perf_event_switch_match(event))
8640 /* Only CPU-wide events are allowed to see next/prev pid/tid */
8641 if (event->ctx->task) {
8642 se->event_id.header.type = PERF_RECORD_SWITCH;
8643 se->event_id.header.size = sizeof(se->event_id.header);
8645 se->event_id.header.type = PERF_RECORD_SWITCH_CPU_WIDE;
8646 se->event_id.header.size = sizeof(se->event_id);
8647 se->event_id.next_prev_pid =
8648 perf_event_pid(event, se->next_prev);
8649 se->event_id.next_prev_tid =
8650 perf_event_tid(event, se->next_prev);
8653 perf_event_header__init_id(&se->event_id.header, &sample, event);
8655 ret = perf_output_begin(&handle, &sample, event, se->event_id.header.size);
8659 if (event->ctx->task)
8660 perf_output_put(&handle, se->event_id.header);
8662 perf_output_put(&handle, se->event_id);
8664 perf_event__output_id_sample(event, &handle, &sample);
8666 perf_output_end(&handle);
8669 static void perf_event_switch(struct task_struct *task,
8670 struct task_struct *next_prev, bool sched_in)
8672 struct perf_switch_event switch_event;
8674 /* N.B. caller checks nr_switch_events != 0 */
8676 switch_event = (struct perf_switch_event){
8678 .next_prev = next_prev,
8682 .misc = sched_in ? 0 : PERF_RECORD_MISC_SWITCH_OUT,
8685 /* .next_prev_pid */
8686 /* .next_prev_tid */
8690 if (!sched_in && task->state == TASK_RUNNING)
8691 switch_event.event_id.header.misc |=
8692 PERF_RECORD_MISC_SWITCH_OUT_PREEMPT;
8694 perf_iterate_sb(perf_event_switch_output,
8700 * IRQ throttle logging
8703 static void perf_log_throttle(struct perf_event *event, int enable)
8705 struct perf_output_handle handle;
8706 struct perf_sample_data sample;
8710 struct perf_event_header header;
8714 } throttle_event = {
8716 .type = PERF_RECORD_THROTTLE,
8718 .size = sizeof(throttle_event),
8720 .time = perf_event_clock(event),
8721 .id = primary_event_id(event),
8722 .stream_id = event->id,
8726 throttle_event.header.type = PERF_RECORD_UNTHROTTLE;
8728 perf_event_header__init_id(&throttle_event.header, &sample, event);
8730 ret = perf_output_begin(&handle, &sample, event,
8731 throttle_event.header.size);
8735 perf_output_put(&handle, throttle_event);
8736 perf_event__output_id_sample(event, &handle, &sample);
8737 perf_output_end(&handle);
8741 * ksymbol register/unregister tracking
8744 struct perf_ksymbol_event {
8748 struct perf_event_header header;
8756 static int perf_event_ksymbol_match(struct perf_event *event)
8758 return event->attr.ksymbol;
8761 static void perf_event_ksymbol_output(struct perf_event *event, void *data)
8763 struct perf_ksymbol_event *ksymbol_event = data;
8764 struct perf_output_handle handle;
8765 struct perf_sample_data sample;
8768 if (!perf_event_ksymbol_match(event))
8771 perf_event_header__init_id(&ksymbol_event->event_id.header,
8773 ret = perf_output_begin(&handle, &sample, event,
8774 ksymbol_event->event_id.header.size);
8778 perf_output_put(&handle, ksymbol_event->event_id);
8779 __output_copy(&handle, ksymbol_event->name, ksymbol_event->name_len);
8780 perf_event__output_id_sample(event, &handle, &sample);
8782 perf_output_end(&handle);
8785 void perf_event_ksymbol(u16 ksym_type, u64 addr, u32 len, bool unregister,
8788 struct perf_ksymbol_event ksymbol_event;
8789 char name[KSYM_NAME_LEN];
8793 if (!atomic_read(&nr_ksymbol_events))
8796 if (ksym_type >= PERF_RECORD_KSYMBOL_TYPE_MAX ||
8797 ksym_type == PERF_RECORD_KSYMBOL_TYPE_UNKNOWN)
8800 strlcpy(name, sym, KSYM_NAME_LEN);
8801 name_len = strlen(name) + 1;
8802 while (!IS_ALIGNED(name_len, sizeof(u64)))
8803 name[name_len++] = '\0';
8804 BUILD_BUG_ON(KSYM_NAME_LEN % sizeof(u64));
8807 flags |= PERF_RECORD_KSYMBOL_FLAGS_UNREGISTER;
8809 ksymbol_event = (struct perf_ksymbol_event){
8811 .name_len = name_len,
8814 .type = PERF_RECORD_KSYMBOL,
8815 .size = sizeof(ksymbol_event.event_id) +
8820 .ksym_type = ksym_type,
8825 perf_iterate_sb(perf_event_ksymbol_output, &ksymbol_event, NULL);
8828 WARN_ONCE(1, "%s: Invalid KSYMBOL type 0x%x\n", __func__, ksym_type);
8832 * bpf program load/unload tracking
8835 struct perf_bpf_event {
8836 struct bpf_prog *prog;
8838 struct perf_event_header header;
8842 u8 tag[BPF_TAG_SIZE];
8846 static int perf_event_bpf_match(struct perf_event *event)
8848 return event->attr.bpf_event;
8851 static void perf_event_bpf_output(struct perf_event *event, void *data)
8853 struct perf_bpf_event *bpf_event = data;
8854 struct perf_output_handle handle;
8855 struct perf_sample_data sample;
8858 if (!perf_event_bpf_match(event))
8861 perf_event_header__init_id(&bpf_event->event_id.header,
8863 ret = perf_output_begin(&handle, data, event,
8864 bpf_event->event_id.header.size);
8868 perf_output_put(&handle, bpf_event->event_id);
8869 perf_event__output_id_sample(event, &handle, &sample);
8871 perf_output_end(&handle);
8874 static void perf_event_bpf_emit_ksymbols(struct bpf_prog *prog,
8875 enum perf_bpf_event_type type)
8877 bool unregister = type == PERF_BPF_EVENT_PROG_UNLOAD;
8880 if (prog->aux->func_cnt == 0) {
8881 perf_event_ksymbol(PERF_RECORD_KSYMBOL_TYPE_BPF,
8882 (u64)(unsigned long)prog->bpf_func,
8883 prog->jited_len, unregister,
8884 prog->aux->ksym.name);
8886 for (i = 0; i < prog->aux->func_cnt; i++) {
8887 struct bpf_prog *subprog = prog->aux->func[i];
8890 PERF_RECORD_KSYMBOL_TYPE_BPF,
8891 (u64)(unsigned long)subprog->bpf_func,
8892 subprog->jited_len, unregister,
8893 prog->aux->ksym.name);
8898 void perf_event_bpf_event(struct bpf_prog *prog,
8899 enum perf_bpf_event_type type,
8902 struct perf_bpf_event bpf_event;
8904 if (type <= PERF_BPF_EVENT_UNKNOWN ||
8905 type >= PERF_BPF_EVENT_MAX)
8909 case PERF_BPF_EVENT_PROG_LOAD:
8910 case PERF_BPF_EVENT_PROG_UNLOAD:
8911 if (atomic_read(&nr_ksymbol_events))
8912 perf_event_bpf_emit_ksymbols(prog, type);
8918 if (!atomic_read(&nr_bpf_events))
8921 bpf_event = (struct perf_bpf_event){
8925 .type = PERF_RECORD_BPF_EVENT,
8926 .size = sizeof(bpf_event.event_id),
8930 .id = prog->aux->id,
8934 BUILD_BUG_ON(BPF_TAG_SIZE % sizeof(u64));
8936 memcpy(bpf_event.event_id.tag, prog->tag, BPF_TAG_SIZE);
8937 perf_iterate_sb(perf_event_bpf_output, &bpf_event, NULL);
8940 struct perf_text_poke_event {
8941 const void *old_bytes;
8942 const void *new_bytes;
8948 struct perf_event_header header;
8954 static int perf_event_text_poke_match(struct perf_event *event)
8956 return event->attr.text_poke;
8959 static void perf_event_text_poke_output(struct perf_event *event, void *data)
8961 struct perf_text_poke_event *text_poke_event = data;
8962 struct perf_output_handle handle;
8963 struct perf_sample_data sample;
8967 if (!perf_event_text_poke_match(event))
8970 perf_event_header__init_id(&text_poke_event->event_id.header, &sample, event);
8972 ret = perf_output_begin(&handle, &sample, event,
8973 text_poke_event->event_id.header.size);
8977 perf_output_put(&handle, text_poke_event->event_id);
8978 perf_output_put(&handle, text_poke_event->old_len);
8979 perf_output_put(&handle, text_poke_event->new_len);
8981 __output_copy(&handle, text_poke_event->old_bytes, text_poke_event->old_len);
8982 __output_copy(&handle, text_poke_event->new_bytes, text_poke_event->new_len);
8984 if (text_poke_event->pad)
8985 __output_copy(&handle, &padding, text_poke_event->pad);
8987 perf_event__output_id_sample(event, &handle, &sample);
8989 perf_output_end(&handle);
8992 void perf_event_text_poke(const void *addr, const void *old_bytes,
8993 size_t old_len, const void *new_bytes, size_t new_len)
8995 struct perf_text_poke_event text_poke_event;
8998 if (!atomic_read(&nr_text_poke_events))
9001 tot = sizeof(text_poke_event.old_len) + old_len;
9002 tot += sizeof(text_poke_event.new_len) + new_len;
9003 pad = ALIGN(tot, sizeof(u64)) - tot;
9005 text_poke_event = (struct perf_text_poke_event){
9006 .old_bytes = old_bytes,
9007 .new_bytes = new_bytes,
9013 .type = PERF_RECORD_TEXT_POKE,
9014 .misc = PERF_RECORD_MISC_KERNEL,
9015 .size = sizeof(text_poke_event.event_id) + tot + pad,
9017 .addr = (unsigned long)addr,
9021 perf_iterate_sb(perf_event_text_poke_output, &text_poke_event, NULL);
9024 void perf_event_itrace_started(struct perf_event *event)
9026 event->attach_state |= PERF_ATTACH_ITRACE;
9029 static void perf_log_itrace_start(struct perf_event *event)
9031 struct perf_output_handle handle;
9032 struct perf_sample_data sample;
9033 struct perf_aux_event {
9034 struct perf_event_header header;
9041 event = event->parent;
9043 if (!(event->pmu->capabilities & PERF_PMU_CAP_ITRACE) ||
9044 event->attach_state & PERF_ATTACH_ITRACE)
9047 rec.header.type = PERF_RECORD_ITRACE_START;
9048 rec.header.misc = 0;
9049 rec.header.size = sizeof(rec);
9050 rec.pid = perf_event_pid(event, current);
9051 rec.tid = perf_event_tid(event, current);
9053 perf_event_header__init_id(&rec.header, &sample, event);
9054 ret = perf_output_begin(&handle, &sample, event, rec.header.size);
9059 perf_output_put(&handle, rec);
9060 perf_event__output_id_sample(event, &handle, &sample);
9062 perf_output_end(&handle);
9066 __perf_event_account_interrupt(struct perf_event *event, int throttle)
9068 struct hw_perf_event *hwc = &event->hw;
9072 seq = __this_cpu_read(perf_throttled_seq);
9073 if (seq != hwc->interrupts_seq) {
9074 hwc->interrupts_seq = seq;
9075 hwc->interrupts = 1;
9078 if (unlikely(throttle
9079 && hwc->interrupts >= max_samples_per_tick)) {
9080 __this_cpu_inc(perf_throttled_count);
9081 tick_dep_set_cpu(smp_processor_id(), TICK_DEP_BIT_PERF_EVENTS);
9082 hwc->interrupts = MAX_INTERRUPTS;
9083 perf_log_throttle(event, 0);
9088 if (event->attr.freq) {
9089 u64 now = perf_clock();
9090 s64 delta = now - hwc->freq_time_stamp;
9092 hwc->freq_time_stamp = now;
9094 if (delta > 0 && delta < 2*TICK_NSEC)
9095 perf_adjust_period(event, delta, hwc->last_period, true);
9101 int perf_event_account_interrupt(struct perf_event *event)
9103 return __perf_event_account_interrupt(event, 1);
9107 * Generic event overflow handling, sampling.
9110 static int __perf_event_overflow(struct perf_event *event,
9111 int throttle, struct perf_sample_data *data,
9112 struct pt_regs *regs)
9114 int events = atomic_read(&event->event_limit);
9118 * Non-sampling counters might still use the PMI to fold short
9119 * hardware counters, ignore those.
9121 if (unlikely(!is_sampling_event(event)))
9124 ret = __perf_event_account_interrupt(event, throttle);
9127 * XXX event_limit might not quite work as expected on inherited
9131 event->pending_kill = POLL_IN;
9132 if (events && atomic_dec_and_test(&event->event_limit)) {
9134 event->pending_kill = POLL_HUP;
9135 event->pending_addr = data->addr;
9137 perf_event_disable_inatomic(event);
9140 READ_ONCE(event->overflow_handler)(event, data, regs);
9142 if (*perf_event_fasync(event) && event->pending_kill) {
9143 event->pending_wakeup = 1;
9144 irq_work_queue(&event->pending);
9150 int perf_event_overflow(struct perf_event *event,
9151 struct perf_sample_data *data,
9152 struct pt_regs *regs)
9154 return __perf_event_overflow(event, 1, data, regs);
9158 * Generic software event infrastructure
9161 struct swevent_htable {
9162 struct swevent_hlist *swevent_hlist;
9163 struct mutex hlist_mutex;
9166 /* Recursion avoidance in each contexts */
9167 int recursion[PERF_NR_CONTEXTS];
9170 static DEFINE_PER_CPU(struct swevent_htable, swevent_htable);
9173 * We directly increment event->count and keep a second value in
9174 * event->hw.period_left to count intervals. This period event
9175 * is kept in the range [-sample_period, 0] so that we can use the
9179 u64 perf_swevent_set_period(struct perf_event *event)
9181 struct hw_perf_event *hwc = &event->hw;
9182 u64 period = hwc->last_period;
9186 hwc->last_period = hwc->sample_period;
9189 old = val = local64_read(&hwc->period_left);
9193 nr = div64_u64(period + val, period);
9194 offset = nr * period;
9196 if (local64_cmpxchg(&hwc->period_left, old, val) != old)
9202 static void perf_swevent_overflow(struct perf_event *event, u64 overflow,
9203 struct perf_sample_data *data,
9204 struct pt_regs *regs)
9206 struct hw_perf_event *hwc = &event->hw;
9210 overflow = perf_swevent_set_period(event);
9212 if (hwc->interrupts == MAX_INTERRUPTS)
9215 for (; overflow; overflow--) {
9216 if (__perf_event_overflow(event, throttle,
9219 * We inhibit the overflow from happening when
9220 * hwc->interrupts == MAX_INTERRUPTS.
9228 static void perf_swevent_event(struct perf_event *event, u64 nr,
9229 struct perf_sample_data *data,
9230 struct pt_regs *regs)
9232 struct hw_perf_event *hwc = &event->hw;
9234 local64_add(nr, &event->count);
9239 if (!is_sampling_event(event))
9242 if ((event->attr.sample_type & PERF_SAMPLE_PERIOD) && !event->attr.freq) {
9244 return perf_swevent_overflow(event, 1, data, regs);
9246 data->period = event->hw.last_period;
9248 if (nr == 1 && hwc->sample_period == 1 && !event->attr.freq)
9249 return perf_swevent_overflow(event, 1, data, regs);
9251 if (local64_add_negative(nr, &hwc->period_left))
9254 perf_swevent_overflow(event, 0, data, regs);
9257 static int perf_exclude_event(struct perf_event *event,
9258 struct pt_regs *regs)
9260 if (event->hw.state & PERF_HES_STOPPED)
9264 if (event->attr.exclude_user && user_mode(regs))
9267 if (event->attr.exclude_kernel && !user_mode(regs))
9274 static int perf_swevent_match(struct perf_event *event,
9275 enum perf_type_id type,
9277 struct perf_sample_data *data,
9278 struct pt_regs *regs)
9280 if (event->attr.type != type)
9283 if (event->attr.config != event_id)
9286 if (perf_exclude_event(event, regs))
9292 static inline u64 swevent_hash(u64 type, u32 event_id)
9294 u64 val = event_id | (type << 32);
9296 return hash_64(val, SWEVENT_HLIST_BITS);
9299 static inline struct hlist_head *
9300 __find_swevent_head(struct swevent_hlist *hlist, u64 type, u32 event_id)
9302 u64 hash = swevent_hash(type, event_id);
9304 return &hlist->heads[hash];
9307 /* For the read side: events when they trigger */
9308 static inline struct hlist_head *
9309 find_swevent_head_rcu(struct swevent_htable *swhash, u64 type, u32 event_id)
9311 struct swevent_hlist *hlist;
9313 hlist = rcu_dereference(swhash->swevent_hlist);
9317 return __find_swevent_head(hlist, type, event_id);
9320 /* For the event head insertion and removal in the hlist */
9321 static inline struct hlist_head *
9322 find_swevent_head(struct swevent_htable *swhash, struct perf_event *event)
9324 struct swevent_hlist *hlist;
9325 u32 event_id = event->attr.config;
9326 u64 type = event->attr.type;
9329 * Event scheduling is always serialized against hlist allocation
9330 * and release. Which makes the protected version suitable here.
9331 * The context lock guarantees that.
9333 hlist = rcu_dereference_protected(swhash->swevent_hlist,
9334 lockdep_is_held(&event->ctx->lock));
9338 return __find_swevent_head(hlist, type, event_id);
9341 static void do_perf_sw_event(enum perf_type_id type, u32 event_id,
9343 struct perf_sample_data *data,
9344 struct pt_regs *regs)
9346 struct swevent_htable *swhash = this_cpu_ptr(&swevent_htable);
9347 struct perf_event *event;
9348 struct hlist_head *head;
9351 head = find_swevent_head_rcu(swhash, type, event_id);
9355 hlist_for_each_entry_rcu(event, head, hlist_entry) {
9356 if (perf_swevent_match(event, type, event_id, data, regs))
9357 perf_swevent_event(event, nr, data, regs);
9363 DEFINE_PER_CPU(struct pt_regs, __perf_regs[4]);
9365 int perf_swevent_get_recursion_context(void)
9367 struct swevent_htable *swhash = this_cpu_ptr(&swevent_htable);
9369 return get_recursion_context(swhash->recursion);
9371 EXPORT_SYMBOL_GPL(perf_swevent_get_recursion_context);
9373 void perf_swevent_put_recursion_context(int rctx)
9375 struct swevent_htable *swhash = this_cpu_ptr(&swevent_htable);
9377 put_recursion_context(swhash->recursion, rctx);
9380 void ___perf_sw_event(u32 event_id, u64 nr, struct pt_regs *regs, u64 addr)
9382 struct perf_sample_data data;
9384 if (WARN_ON_ONCE(!regs))
9387 perf_sample_data_init(&data, addr, 0);
9388 do_perf_sw_event(PERF_TYPE_SOFTWARE, event_id, nr, &data, regs);
9391 void __perf_sw_event(u32 event_id, u64 nr, struct pt_regs *regs, u64 addr)
9395 preempt_disable_notrace();
9396 rctx = perf_swevent_get_recursion_context();
9397 if (unlikely(rctx < 0))
9400 ___perf_sw_event(event_id, nr, regs, addr);
9402 perf_swevent_put_recursion_context(rctx);
9404 preempt_enable_notrace();
9407 static void perf_swevent_read(struct perf_event *event)
9411 static int perf_swevent_add(struct perf_event *event, int flags)
9413 struct swevent_htable *swhash = this_cpu_ptr(&swevent_htable);
9414 struct hw_perf_event *hwc = &event->hw;
9415 struct hlist_head *head;
9417 if (is_sampling_event(event)) {
9418 hwc->last_period = hwc->sample_period;
9419 perf_swevent_set_period(event);
9422 hwc->state = !(flags & PERF_EF_START);
9424 head = find_swevent_head(swhash, event);
9425 if (WARN_ON_ONCE(!head))
9428 hlist_add_head_rcu(&event->hlist_entry, head);
9429 perf_event_update_userpage(event);
9434 static void perf_swevent_del(struct perf_event *event, int flags)
9436 hlist_del_rcu(&event->hlist_entry);
9439 static void perf_swevent_start(struct perf_event *event, int flags)
9441 event->hw.state = 0;
9444 static void perf_swevent_stop(struct perf_event *event, int flags)
9446 event->hw.state = PERF_HES_STOPPED;
9449 /* Deref the hlist from the update side */
9450 static inline struct swevent_hlist *
9451 swevent_hlist_deref(struct swevent_htable *swhash)
9453 return rcu_dereference_protected(swhash->swevent_hlist,
9454 lockdep_is_held(&swhash->hlist_mutex));
9457 static void swevent_hlist_release(struct swevent_htable *swhash)
9459 struct swevent_hlist *hlist = swevent_hlist_deref(swhash);
9464 RCU_INIT_POINTER(swhash->swevent_hlist, NULL);
9465 kfree_rcu(hlist, rcu_head);
9468 static void swevent_hlist_put_cpu(int cpu)
9470 struct swevent_htable *swhash = &per_cpu(swevent_htable, cpu);
9472 mutex_lock(&swhash->hlist_mutex);
9474 if (!--swhash->hlist_refcount)
9475 swevent_hlist_release(swhash);
9477 mutex_unlock(&swhash->hlist_mutex);
9480 static void swevent_hlist_put(void)
9484 for_each_possible_cpu(cpu)
9485 swevent_hlist_put_cpu(cpu);
9488 static int swevent_hlist_get_cpu(int cpu)
9490 struct swevent_htable *swhash = &per_cpu(swevent_htable, cpu);
9493 mutex_lock(&swhash->hlist_mutex);
9494 if (!swevent_hlist_deref(swhash) &&
9495 cpumask_test_cpu(cpu, perf_online_mask)) {
9496 struct swevent_hlist *hlist;
9498 hlist = kzalloc(sizeof(*hlist), GFP_KERNEL);
9503 rcu_assign_pointer(swhash->swevent_hlist, hlist);
9505 swhash->hlist_refcount++;
9507 mutex_unlock(&swhash->hlist_mutex);
9512 static int swevent_hlist_get(void)
9514 int err, cpu, failed_cpu;
9516 mutex_lock(&pmus_lock);
9517 for_each_possible_cpu(cpu) {
9518 err = swevent_hlist_get_cpu(cpu);
9524 mutex_unlock(&pmus_lock);
9527 for_each_possible_cpu(cpu) {
9528 if (cpu == failed_cpu)
9530 swevent_hlist_put_cpu(cpu);
9532 mutex_unlock(&pmus_lock);
9536 struct static_key perf_swevent_enabled[PERF_COUNT_SW_MAX];
9538 static void sw_perf_event_destroy(struct perf_event *event)
9540 u64 event_id = event->attr.config;
9542 WARN_ON(event->parent);
9544 static_key_slow_dec(&perf_swevent_enabled[event_id]);
9545 swevent_hlist_put();
9548 static int perf_swevent_init(struct perf_event *event)
9550 u64 event_id = event->attr.config;
9552 if (event->attr.type != PERF_TYPE_SOFTWARE)
9556 * no branch sampling for software events
9558 if (has_branch_stack(event))
9562 case PERF_COUNT_SW_CPU_CLOCK:
9563 case PERF_COUNT_SW_TASK_CLOCK:
9570 if (event_id >= PERF_COUNT_SW_MAX)
9573 if (!event->parent) {
9576 err = swevent_hlist_get();
9580 static_key_slow_inc(&perf_swevent_enabled[event_id]);
9581 event->destroy = sw_perf_event_destroy;
9587 static struct pmu perf_swevent = {
9588 .task_ctx_nr = perf_sw_context,
9590 .capabilities = PERF_PMU_CAP_NO_NMI,
9592 .event_init = perf_swevent_init,
9593 .add = perf_swevent_add,
9594 .del = perf_swevent_del,
9595 .start = perf_swevent_start,
9596 .stop = perf_swevent_stop,
9597 .read = perf_swevent_read,
9600 #ifdef CONFIG_EVENT_TRACING
9602 static int perf_tp_filter_match(struct perf_event *event,
9603 struct perf_sample_data *data)
9605 void *record = data->raw->frag.data;
9607 /* only top level events have filters set */
9609 event = event->parent;
9611 if (likely(!event->filter) || filter_match_preds(event->filter, record))
9616 static int perf_tp_event_match(struct perf_event *event,
9617 struct perf_sample_data *data,
9618 struct pt_regs *regs)
9620 if (event->hw.state & PERF_HES_STOPPED)
9623 * If exclude_kernel, only trace user-space tracepoints (uprobes)
9625 if (event->attr.exclude_kernel && !user_mode(regs))
9628 if (!perf_tp_filter_match(event, data))
9634 void perf_trace_run_bpf_submit(void *raw_data, int size, int rctx,
9635 struct trace_event_call *call, u64 count,
9636 struct pt_regs *regs, struct hlist_head *head,
9637 struct task_struct *task)
9639 if (bpf_prog_array_valid(call)) {
9640 *(struct pt_regs **)raw_data = regs;
9641 if (!trace_call_bpf(call, raw_data) || hlist_empty(head)) {
9642 perf_swevent_put_recursion_context(rctx);
9646 perf_tp_event(call->event.type, count, raw_data, size, regs, head,
9649 EXPORT_SYMBOL_GPL(perf_trace_run_bpf_submit);
9651 void perf_tp_event(u16 event_type, u64 count, void *record, int entry_size,
9652 struct pt_regs *regs, struct hlist_head *head, int rctx,
9653 struct task_struct *task)
9655 struct perf_sample_data data;
9656 struct perf_event *event;
9658 struct perf_raw_record raw = {
9665 perf_sample_data_init(&data, 0, 0);
9668 perf_trace_buf_update(record, event_type);
9670 hlist_for_each_entry_rcu(event, head, hlist_entry) {
9671 if (perf_tp_event_match(event, &data, regs))
9672 perf_swevent_event(event, count, &data, regs);
9676 * If we got specified a target task, also iterate its context and
9677 * deliver this event there too.
9679 if (task && task != current) {
9680 struct perf_event_context *ctx;
9681 struct trace_entry *entry = record;
9684 ctx = rcu_dereference(task->perf_event_ctxp[perf_sw_context]);
9688 list_for_each_entry_rcu(event, &ctx->event_list, event_entry) {
9689 if (event->cpu != smp_processor_id())
9691 if (event->attr.type != PERF_TYPE_TRACEPOINT)
9693 if (event->attr.config != entry->type)
9695 if (perf_tp_event_match(event, &data, regs))
9696 perf_swevent_event(event, count, &data, regs);
9702 perf_swevent_put_recursion_context(rctx);
9704 EXPORT_SYMBOL_GPL(perf_tp_event);
9706 static void tp_perf_event_destroy(struct perf_event *event)
9708 perf_trace_destroy(event);
9711 static int perf_tp_event_init(struct perf_event *event)
9715 if (event->attr.type != PERF_TYPE_TRACEPOINT)
9719 * no branch sampling for tracepoint events
9721 if (has_branch_stack(event))
9724 err = perf_trace_init(event);
9728 event->destroy = tp_perf_event_destroy;
9733 static struct pmu perf_tracepoint = {
9734 .task_ctx_nr = perf_sw_context,
9736 .event_init = perf_tp_event_init,
9737 .add = perf_trace_add,
9738 .del = perf_trace_del,
9739 .start = perf_swevent_start,
9740 .stop = perf_swevent_stop,
9741 .read = perf_swevent_read,
9744 #if defined(CONFIG_KPROBE_EVENTS) || defined(CONFIG_UPROBE_EVENTS)
9746 * Flags in config, used by dynamic PMU kprobe and uprobe
9747 * The flags should match following PMU_FORMAT_ATTR().
9749 * PERF_PROBE_CONFIG_IS_RETPROBE if set, create kretprobe/uretprobe
9750 * if not set, create kprobe/uprobe
9752 * The following values specify a reference counter (or semaphore in the
9753 * terminology of tools like dtrace, systemtap, etc.) Userspace Statically
9754 * Defined Tracepoints (USDT). Currently, we use 40 bit for the offset.
9756 * PERF_UPROBE_REF_CTR_OFFSET_BITS # of bits in config as th offset
9757 * PERF_UPROBE_REF_CTR_OFFSET_SHIFT # of bits to shift left
9759 enum perf_probe_config {
9760 PERF_PROBE_CONFIG_IS_RETPROBE = 1U << 0, /* [k,u]retprobe */
9761 PERF_UPROBE_REF_CTR_OFFSET_BITS = 32,
9762 PERF_UPROBE_REF_CTR_OFFSET_SHIFT = 64 - PERF_UPROBE_REF_CTR_OFFSET_BITS,
9765 PMU_FORMAT_ATTR(retprobe, "config:0");
9768 #ifdef CONFIG_KPROBE_EVENTS
9769 static struct attribute *kprobe_attrs[] = {
9770 &format_attr_retprobe.attr,
9774 static struct attribute_group kprobe_format_group = {
9776 .attrs = kprobe_attrs,
9779 static const struct attribute_group *kprobe_attr_groups[] = {
9780 &kprobe_format_group,
9784 static int perf_kprobe_event_init(struct perf_event *event);
9785 static struct pmu perf_kprobe = {
9786 .task_ctx_nr = perf_sw_context,
9787 .event_init = perf_kprobe_event_init,
9788 .add = perf_trace_add,
9789 .del = perf_trace_del,
9790 .start = perf_swevent_start,
9791 .stop = perf_swevent_stop,
9792 .read = perf_swevent_read,
9793 .attr_groups = kprobe_attr_groups,
9796 static int perf_kprobe_event_init(struct perf_event *event)
9801 if (event->attr.type != perf_kprobe.type)
9804 if (!perfmon_capable())
9808 * no branch sampling for probe events
9810 if (has_branch_stack(event))
9813 is_retprobe = event->attr.config & PERF_PROBE_CONFIG_IS_RETPROBE;
9814 err = perf_kprobe_init(event, is_retprobe);
9818 event->destroy = perf_kprobe_destroy;
9822 #endif /* CONFIG_KPROBE_EVENTS */
9824 #ifdef CONFIG_UPROBE_EVENTS
9825 PMU_FORMAT_ATTR(ref_ctr_offset, "config:32-63");
9827 static struct attribute *uprobe_attrs[] = {
9828 &format_attr_retprobe.attr,
9829 &format_attr_ref_ctr_offset.attr,
9833 static struct attribute_group uprobe_format_group = {
9835 .attrs = uprobe_attrs,
9838 static const struct attribute_group *uprobe_attr_groups[] = {
9839 &uprobe_format_group,
9843 static int perf_uprobe_event_init(struct perf_event *event);
9844 static struct pmu perf_uprobe = {
9845 .task_ctx_nr = perf_sw_context,
9846 .event_init = perf_uprobe_event_init,
9847 .add = perf_trace_add,
9848 .del = perf_trace_del,
9849 .start = perf_swevent_start,
9850 .stop = perf_swevent_stop,
9851 .read = perf_swevent_read,
9852 .attr_groups = uprobe_attr_groups,
9855 static int perf_uprobe_event_init(struct perf_event *event)
9858 unsigned long ref_ctr_offset;
9861 if (event->attr.type != perf_uprobe.type)
9864 if (!perfmon_capable())
9868 * no branch sampling for probe events
9870 if (has_branch_stack(event))
9873 is_retprobe = event->attr.config & PERF_PROBE_CONFIG_IS_RETPROBE;
9874 ref_ctr_offset = event->attr.config >> PERF_UPROBE_REF_CTR_OFFSET_SHIFT;
9875 err = perf_uprobe_init(event, ref_ctr_offset, is_retprobe);
9879 event->destroy = perf_uprobe_destroy;
9883 #endif /* CONFIG_UPROBE_EVENTS */
9885 static inline void perf_tp_register(void)
9887 perf_pmu_register(&perf_tracepoint, "tracepoint", PERF_TYPE_TRACEPOINT);
9888 #ifdef CONFIG_KPROBE_EVENTS
9889 perf_pmu_register(&perf_kprobe, "kprobe", -1);
9891 #ifdef CONFIG_UPROBE_EVENTS
9892 perf_pmu_register(&perf_uprobe, "uprobe", -1);
9896 static void perf_event_free_filter(struct perf_event *event)
9898 ftrace_profile_free_filter(event);
9901 #ifdef CONFIG_BPF_SYSCALL
9902 static void bpf_overflow_handler(struct perf_event *event,
9903 struct perf_sample_data *data,
9904 struct pt_regs *regs)
9906 struct bpf_perf_event_data_kern ctx = {
9912 ctx.regs = perf_arch_bpf_user_pt_regs(regs);
9913 if (unlikely(__this_cpu_inc_return(bpf_prog_active) != 1))
9916 ret = BPF_PROG_RUN(event->prog, &ctx);
9919 __this_cpu_dec(bpf_prog_active);
9923 event->orig_overflow_handler(event, data, regs);
9926 static int perf_event_set_bpf_handler(struct perf_event *event, u32 prog_fd)
9928 struct bpf_prog *prog;
9930 if (event->overflow_handler_context)
9931 /* hw breakpoint or kernel counter */
9937 prog = bpf_prog_get_type(prog_fd, BPF_PROG_TYPE_PERF_EVENT);
9939 return PTR_ERR(prog);
9941 if (event->attr.precise_ip &&
9942 prog->call_get_stack &&
9943 (!(event->attr.sample_type & __PERF_SAMPLE_CALLCHAIN_EARLY) ||
9944 event->attr.exclude_callchain_kernel ||
9945 event->attr.exclude_callchain_user)) {
9947 * On perf_event with precise_ip, calling bpf_get_stack()
9948 * may trigger unwinder warnings and occasional crashes.
9949 * bpf_get_[stack|stackid] works around this issue by using
9950 * callchain attached to perf_sample_data. If the
9951 * perf_event does not full (kernel and user) callchain
9952 * attached to perf_sample_data, do not allow attaching BPF
9953 * program that calls bpf_get_[stack|stackid].
9960 event->orig_overflow_handler = READ_ONCE(event->overflow_handler);
9961 WRITE_ONCE(event->overflow_handler, bpf_overflow_handler);
9965 static void perf_event_free_bpf_handler(struct perf_event *event)
9967 struct bpf_prog *prog = event->prog;
9972 WRITE_ONCE(event->overflow_handler, event->orig_overflow_handler);
9977 static int perf_event_set_bpf_handler(struct perf_event *event, u32 prog_fd)
9981 static void perf_event_free_bpf_handler(struct perf_event *event)
9987 * returns true if the event is a tracepoint, or a kprobe/upprobe created
9988 * with perf_event_open()
9990 static inline bool perf_event_is_tracing(struct perf_event *event)
9992 if (event->pmu == &perf_tracepoint)
9994 #ifdef CONFIG_KPROBE_EVENTS
9995 if (event->pmu == &perf_kprobe)
9998 #ifdef CONFIG_UPROBE_EVENTS
9999 if (event->pmu == &perf_uprobe)
10005 static int perf_event_set_bpf_prog(struct perf_event *event, u32 prog_fd)
10007 bool is_kprobe, is_tracepoint, is_syscall_tp;
10008 struct bpf_prog *prog;
10011 if (!perf_event_is_tracing(event))
10012 return perf_event_set_bpf_handler(event, prog_fd);
10014 is_kprobe = event->tp_event->flags & TRACE_EVENT_FL_UKPROBE;
10015 is_tracepoint = event->tp_event->flags & TRACE_EVENT_FL_TRACEPOINT;
10016 is_syscall_tp = is_syscall_trace_event(event->tp_event);
10017 if (!is_kprobe && !is_tracepoint && !is_syscall_tp)
10018 /* bpf programs can only be attached to u/kprobe or tracepoint */
10021 prog = bpf_prog_get(prog_fd);
10023 return PTR_ERR(prog);
10025 if ((is_kprobe && prog->type != BPF_PROG_TYPE_KPROBE) ||
10026 (is_tracepoint && prog->type != BPF_PROG_TYPE_TRACEPOINT) ||
10027 (is_syscall_tp && prog->type != BPF_PROG_TYPE_TRACEPOINT)) {
10028 /* valid fd, but invalid bpf program type */
10029 bpf_prog_put(prog);
10033 /* Kprobe override only works for kprobes, not uprobes. */
10034 if (prog->kprobe_override &&
10035 !(event->tp_event->flags & TRACE_EVENT_FL_KPROBE)) {
10036 bpf_prog_put(prog);
10040 if (is_tracepoint || is_syscall_tp) {
10041 int off = trace_event_get_offsets(event->tp_event);
10043 if (prog->aux->max_ctx_offset > off) {
10044 bpf_prog_put(prog);
10049 ret = perf_event_attach_bpf_prog(event, prog);
10051 bpf_prog_put(prog);
10055 static void perf_event_free_bpf_prog(struct perf_event *event)
10057 if (!perf_event_is_tracing(event)) {
10058 perf_event_free_bpf_handler(event);
10061 perf_event_detach_bpf_prog(event);
10066 static inline void perf_tp_register(void)
10070 static void perf_event_free_filter(struct perf_event *event)
10074 static int perf_event_set_bpf_prog(struct perf_event *event, u32 prog_fd)
10079 static void perf_event_free_bpf_prog(struct perf_event *event)
10082 #endif /* CONFIG_EVENT_TRACING */
10084 #ifdef CONFIG_HAVE_HW_BREAKPOINT
10085 void perf_bp_event(struct perf_event *bp, void *data)
10087 struct perf_sample_data sample;
10088 struct pt_regs *regs = data;
10090 perf_sample_data_init(&sample, bp->attr.bp_addr, 0);
10092 if (!bp->hw.state && !perf_exclude_event(bp, regs))
10093 perf_swevent_event(bp, 1, &sample, regs);
10098 * Allocate a new address filter
10100 static struct perf_addr_filter *
10101 perf_addr_filter_new(struct perf_event *event, struct list_head *filters)
10103 int node = cpu_to_node(event->cpu == -1 ? 0 : event->cpu);
10104 struct perf_addr_filter *filter;
10106 filter = kzalloc_node(sizeof(*filter), GFP_KERNEL, node);
10110 INIT_LIST_HEAD(&filter->entry);
10111 list_add_tail(&filter->entry, filters);
10116 static void free_filters_list(struct list_head *filters)
10118 struct perf_addr_filter *filter, *iter;
10120 list_for_each_entry_safe(filter, iter, filters, entry) {
10121 path_put(&filter->path);
10122 list_del(&filter->entry);
10128 * Free existing address filters and optionally install new ones
10130 static void perf_addr_filters_splice(struct perf_event *event,
10131 struct list_head *head)
10133 unsigned long flags;
10136 if (!has_addr_filter(event))
10139 /* don't bother with children, they don't have their own filters */
10143 raw_spin_lock_irqsave(&event->addr_filters.lock, flags);
10145 list_splice_init(&event->addr_filters.list, &list);
10147 list_splice(head, &event->addr_filters.list);
10149 raw_spin_unlock_irqrestore(&event->addr_filters.lock, flags);
10151 free_filters_list(&list);
10155 * Scan through mm's vmas and see if one of them matches the
10156 * @filter; if so, adjust filter's address range.
10157 * Called with mm::mmap_lock down for reading.
10159 static void perf_addr_filter_apply(struct perf_addr_filter *filter,
10160 struct mm_struct *mm,
10161 struct perf_addr_filter_range *fr)
10163 struct vm_area_struct *vma;
10165 for (vma = mm->mmap; vma; vma = vma->vm_next) {
10169 if (perf_addr_filter_vma_adjust(filter, vma, fr))
10175 * Update event's address range filters based on the
10176 * task's existing mappings, if any.
10178 static void perf_event_addr_filters_apply(struct perf_event *event)
10180 struct perf_addr_filters_head *ifh = perf_event_addr_filters(event);
10181 struct task_struct *task = READ_ONCE(event->ctx->task);
10182 struct perf_addr_filter *filter;
10183 struct mm_struct *mm = NULL;
10184 unsigned int count = 0;
10185 unsigned long flags;
10188 * We may observe TASK_TOMBSTONE, which means that the event tear-down
10189 * will stop on the parent's child_mutex that our caller is also holding
10191 if (task == TASK_TOMBSTONE)
10194 if (ifh->nr_file_filters) {
10195 mm = get_task_mm(event->ctx->task);
10199 mmap_read_lock(mm);
10202 raw_spin_lock_irqsave(&ifh->lock, flags);
10203 list_for_each_entry(filter, &ifh->list, entry) {
10204 if (filter->path.dentry) {
10206 * Adjust base offset if the filter is associated to a
10207 * binary that needs to be mapped:
10209 event->addr_filter_ranges[count].start = 0;
10210 event->addr_filter_ranges[count].size = 0;
10212 perf_addr_filter_apply(filter, mm, &event->addr_filter_ranges[count]);
10214 event->addr_filter_ranges[count].start = filter->offset;
10215 event->addr_filter_ranges[count].size = filter->size;
10221 event->addr_filters_gen++;
10222 raw_spin_unlock_irqrestore(&ifh->lock, flags);
10224 if (ifh->nr_file_filters) {
10225 mmap_read_unlock(mm);
10231 perf_event_stop(event, 1);
10235 * Address range filtering: limiting the data to certain
10236 * instruction address ranges. Filters are ioctl()ed to us from
10237 * userspace as ascii strings.
10239 * Filter string format:
10241 * ACTION RANGE_SPEC
10242 * where ACTION is one of the
10243 * * "filter": limit the trace to this region
10244 * * "start": start tracing from this address
10245 * * "stop": stop tracing at this address/region;
10247 * * for kernel addresses: <start address>[/<size>]
10248 * * for object files: <start address>[/<size>]@</path/to/object/file>
10250 * if <size> is not specified or is zero, the range is treated as a single
10251 * address; not valid for ACTION=="filter".
10265 IF_STATE_ACTION = 0,
10270 static const match_table_t if_tokens = {
10271 { IF_ACT_FILTER, "filter" },
10272 { IF_ACT_START, "start" },
10273 { IF_ACT_STOP, "stop" },
10274 { IF_SRC_FILE, "%u/%u@%s" },
10275 { IF_SRC_KERNEL, "%u/%u" },
10276 { IF_SRC_FILEADDR, "%u@%s" },
10277 { IF_SRC_KERNELADDR, "%u" },
10278 { IF_ACT_NONE, NULL },
10282 * Address filter string parser
10285 perf_event_parse_addr_filter(struct perf_event *event, char *fstr,
10286 struct list_head *filters)
10288 struct perf_addr_filter *filter = NULL;
10289 char *start, *orig, *filename = NULL;
10290 substring_t args[MAX_OPT_ARGS];
10291 int state = IF_STATE_ACTION, token;
10292 unsigned int kernel = 0;
10295 orig = fstr = kstrdup(fstr, GFP_KERNEL);
10299 while ((start = strsep(&fstr, " ,\n")) != NULL) {
10300 static const enum perf_addr_filter_action_t actions[] = {
10301 [IF_ACT_FILTER] = PERF_ADDR_FILTER_ACTION_FILTER,
10302 [IF_ACT_START] = PERF_ADDR_FILTER_ACTION_START,
10303 [IF_ACT_STOP] = PERF_ADDR_FILTER_ACTION_STOP,
10310 /* filter definition begins */
10311 if (state == IF_STATE_ACTION) {
10312 filter = perf_addr_filter_new(event, filters);
10317 token = match_token(start, if_tokens, args);
10319 case IF_ACT_FILTER:
10322 if (state != IF_STATE_ACTION)
10325 filter->action = actions[token];
10326 state = IF_STATE_SOURCE;
10329 case IF_SRC_KERNELADDR:
10330 case IF_SRC_KERNEL:
10334 case IF_SRC_FILEADDR:
10336 if (state != IF_STATE_SOURCE)
10340 ret = kstrtoul(args[0].from, 0, &filter->offset);
10344 if (token == IF_SRC_KERNEL || token == IF_SRC_FILE) {
10346 ret = kstrtoul(args[1].from, 0, &filter->size);
10351 if (token == IF_SRC_FILE || token == IF_SRC_FILEADDR) {
10352 int fpos = token == IF_SRC_FILE ? 2 : 1;
10355 filename = match_strdup(&args[fpos]);
10362 state = IF_STATE_END;
10370 * Filter definition is fully parsed, validate and install it.
10371 * Make sure that it doesn't contradict itself or the event's
10374 if (state == IF_STATE_END) {
10376 if (kernel && event->attr.exclude_kernel)
10380 * ACTION "filter" must have a non-zero length region
10383 if (filter->action == PERF_ADDR_FILTER_ACTION_FILTER &&
10392 * For now, we only support file-based filters
10393 * in per-task events; doing so for CPU-wide
10394 * events requires additional context switching
10395 * trickery, since same object code will be
10396 * mapped at different virtual addresses in
10397 * different processes.
10400 if (!event->ctx->task)
10403 /* look up the path and grab its inode */
10404 ret = kern_path(filename, LOOKUP_FOLLOW,
10410 if (!filter->path.dentry ||
10411 !S_ISREG(d_inode(filter->path.dentry)
10415 event->addr_filters.nr_file_filters++;
10418 /* ready to consume more filters */
10419 state = IF_STATE_ACTION;
10424 if (state != IF_STATE_ACTION)
10434 free_filters_list(filters);
10441 perf_event_set_addr_filter(struct perf_event *event, char *filter_str)
10443 LIST_HEAD(filters);
10447 * Since this is called in perf_ioctl() path, we're already holding
10450 lockdep_assert_held(&event->ctx->mutex);
10452 if (WARN_ON_ONCE(event->parent))
10455 ret = perf_event_parse_addr_filter(event, filter_str, &filters);
10457 goto fail_clear_files;
10459 ret = event->pmu->addr_filters_validate(&filters);
10461 goto fail_free_filters;
10463 /* remove existing filters, if any */
10464 perf_addr_filters_splice(event, &filters);
10466 /* install new filters */
10467 perf_event_for_each_child(event, perf_event_addr_filters_apply);
10472 free_filters_list(&filters);
10475 event->addr_filters.nr_file_filters = 0;
10480 static int perf_event_set_filter(struct perf_event *event, void __user *arg)
10485 filter_str = strndup_user(arg, PAGE_SIZE);
10486 if (IS_ERR(filter_str))
10487 return PTR_ERR(filter_str);
10489 #ifdef CONFIG_EVENT_TRACING
10490 if (perf_event_is_tracing(event)) {
10491 struct perf_event_context *ctx = event->ctx;
10494 * Beware, here be dragons!!
10496 * the tracepoint muck will deadlock against ctx->mutex, but
10497 * the tracepoint stuff does not actually need it. So
10498 * temporarily drop ctx->mutex. As per perf_event_ctx_lock() we
10499 * already have a reference on ctx.
10501 * This can result in event getting moved to a different ctx,
10502 * but that does not affect the tracepoint state.
10504 mutex_unlock(&ctx->mutex);
10505 ret = ftrace_profile_set_filter(event, event->attr.config, filter_str);
10506 mutex_lock(&ctx->mutex);
10509 if (has_addr_filter(event))
10510 ret = perf_event_set_addr_filter(event, filter_str);
10517 * hrtimer based swevent callback
10520 static enum hrtimer_restart perf_swevent_hrtimer(struct hrtimer *hrtimer)
10522 enum hrtimer_restart ret = HRTIMER_RESTART;
10523 struct perf_sample_data data;
10524 struct pt_regs *regs;
10525 struct perf_event *event;
10528 event = container_of(hrtimer, struct perf_event, hw.hrtimer);
10530 if (event->state != PERF_EVENT_STATE_ACTIVE)
10531 return HRTIMER_NORESTART;
10533 event->pmu->read(event);
10535 perf_sample_data_init(&data, 0, event->hw.last_period);
10536 regs = get_irq_regs();
10538 if (regs && !perf_exclude_event(event, regs)) {
10539 if (!(event->attr.exclude_idle && is_idle_task(current)))
10540 if (__perf_event_overflow(event, 1, &data, regs))
10541 ret = HRTIMER_NORESTART;
10544 period = max_t(u64, 10000, event->hw.sample_period);
10545 hrtimer_forward_now(hrtimer, ns_to_ktime(period));
10550 static void perf_swevent_start_hrtimer(struct perf_event *event)
10552 struct hw_perf_event *hwc = &event->hw;
10555 if (!is_sampling_event(event))
10558 period = local64_read(&hwc->period_left);
10563 local64_set(&hwc->period_left, 0);
10565 period = max_t(u64, 10000, hwc->sample_period);
10567 hrtimer_start(&hwc->hrtimer, ns_to_ktime(period),
10568 HRTIMER_MODE_REL_PINNED_HARD);
10571 static void perf_swevent_cancel_hrtimer(struct perf_event *event)
10573 struct hw_perf_event *hwc = &event->hw;
10575 if (is_sampling_event(event)) {
10576 ktime_t remaining = hrtimer_get_remaining(&hwc->hrtimer);
10577 local64_set(&hwc->period_left, ktime_to_ns(remaining));
10579 hrtimer_cancel(&hwc->hrtimer);
10583 static void perf_swevent_init_hrtimer(struct perf_event *event)
10585 struct hw_perf_event *hwc = &event->hw;
10587 if (!is_sampling_event(event))
10590 hrtimer_init(&hwc->hrtimer, CLOCK_MONOTONIC, HRTIMER_MODE_REL_HARD);
10591 hwc->hrtimer.function = perf_swevent_hrtimer;
10594 * Since hrtimers have a fixed rate, we can do a static freq->period
10595 * mapping and avoid the whole period adjust feedback stuff.
10597 if (event->attr.freq) {
10598 long freq = event->attr.sample_freq;
10600 event->attr.sample_period = NSEC_PER_SEC / freq;
10601 hwc->sample_period = event->attr.sample_period;
10602 local64_set(&hwc->period_left, hwc->sample_period);
10603 hwc->last_period = hwc->sample_period;
10604 event->attr.freq = 0;
10609 * Software event: cpu wall time clock
10612 static void cpu_clock_event_update(struct perf_event *event)
10617 now = local_clock();
10618 prev = local64_xchg(&event->hw.prev_count, now);
10619 local64_add(now - prev, &event->count);
10622 static void cpu_clock_event_start(struct perf_event *event, int flags)
10624 local64_set(&event->hw.prev_count, local_clock());
10625 perf_swevent_start_hrtimer(event);
10628 static void cpu_clock_event_stop(struct perf_event *event, int flags)
10630 perf_swevent_cancel_hrtimer(event);
10631 cpu_clock_event_update(event);
10634 static int cpu_clock_event_add(struct perf_event *event, int flags)
10636 if (flags & PERF_EF_START)
10637 cpu_clock_event_start(event, flags);
10638 perf_event_update_userpage(event);
10643 static void cpu_clock_event_del(struct perf_event *event, int flags)
10645 cpu_clock_event_stop(event, flags);
10648 static void cpu_clock_event_read(struct perf_event *event)
10650 cpu_clock_event_update(event);
10653 static int cpu_clock_event_init(struct perf_event *event)
10655 if (event->attr.type != PERF_TYPE_SOFTWARE)
10658 if (event->attr.config != PERF_COUNT_SW_CPU_CLOCK)
10662 * no branch sampling for software events
10664 if (has_branch_stack(event))
10665 return -EOPNOTSUPP;
10667 perf_swevent_init_hrtimer(event);
10672 static struct pmu perf_cpu_clock = {
10673 .task_ctx_nr = perf_sw_context,
10675 .capabilities = PERF_PMU_CAP_NO_NMI,
10677 .event_init = cpu_clock_event_init,
10678 .add = cpu_clock_event_add,
10679 .del = cpu_clock_event_del,
10680 .start = cpu_clock_event_start,
10681 .stop = cpu_clock_event_stop,
10682 .read = cpu_clock_event_read,
10686 * Software event: task time clock
10689 static void task_clock_event_update(struct perf_event *event, u64 now)
10694 prev = local64_xchg(&event->hw.prev_count, now);
10695 delta = now - prev;
10696 local64_add(delta, &event->count);
10699 static void task_clock_event_start(struct perf_event *event, int flags)
10701 local64_set(&event->hw.prev_count, event->ctx->time);
10702 perf_swevent_start_hrtimer(event);
10705 static void task_clock_event_stop(struct perf_event *event, int flags)
10707 perf_swevent_cancel_hrtimer(event);
10708 task_clock_event_update(event, event->ctx->time);
10711 static int task_clock_event_add(struct perf_event *event, int flags)
10713 if (flags & PERF_EF_START)
10714 task_clock_event_start(event, flags);
10715 perf_event_update_userpage(event);
10720 static void task_clock_event_del(struct perf_event *event, int flags)
10722 task_clock_event_stop(event, PERF_EF_UPDATE);
10725 static void task_clock_event_read(struct perf_event *event)
10727 u64 now = perf_clock();
10728 u64 delta = now - event->ctx->timestamp;
10729 u64 time = event->ctx->time + delta;
10731 task_clock_event_update(event, time);
10734 static int task_clock_event_init(struct perf_event *event)
10736 if (event->attr.type != PERF_TYPE_SOFTWARE)
10739 if (event->attr.config != PERF_COUNT_SW_TASK_CLOCK)
10743 * no branch sampling for software events
10745 if (has_branch_stack(event))
10746 return -EOPNOTSUPP;
10748 perf_swevent_init_hrtimer(event);
10753 static struct pmu perf_task_clock = {
10754 .task_ctx_nr = perf_sw_context,
10756 .capabilities = PERF_PMU_CAP_NO_NMI,
10758 .event_init = task_clock_event_init,
10759 .add = task_clock_event_add,
10760 .del = task_clock_event_del,
10761 .start = task_clock_event_start,
10762 .stop = task_clock_event_stop,
10763 .read = task_clock_event_read,
10766 static void perf_pmu_nop_void(struct pmu *pmu)
10770 static void perf_pmu_nop_txn(struct pmu *pmu, unsigned int flags)
10774 static int perf_pmu_nop_int(struct pmu *pmu)
10779 static int perf_event_nop_int(struct perf_event *event, u64 value)
10784 static DEFINE_PER_CPU(unsigned int, nop_txn_flags);
10786 static void perf_pmu_start_txn(struct pmu *pmu, unsigned int flags)
10788 __this_cpu_write(nop_txn_flags, flags);
10790 if (flags & ~PERF_PMU_TXN_ADD)
10793 perf_pmu_disable(pmu);
10796 static int perf_pmu_commit_txn(struct pmu *pmu)
10798 unsigned int flags = __this_cpu_read(nop_txn_flags);
10800 __this_cpu_write(nop_txn_flags, 0);
10802 if (flags & ~PERF_PMU_TXN_ADD)
10805 perf_pmu_enable(pmu);
10809 static void perf_pmu_cancel_txn(struct pmu *pmu)
10811 unsigned int flags = __this_cpu_read(nop_txn_flags);
10813 __this_cpu_write(nop_txn_flags, 0);
10815 if (flags & ~PERF_PMU_TXN_ADD)
10818 perf_pmu_enable(pmu);
10821 static int perf_event_idx_default(struct perf_event *event)
10827 * Ensures all contexts with the same task_ctx_nr have the same
10828 * pmu_cpu_context too.
10830 static struct perf_cpu_context __percpu *find_pmu_context(int ctxn)
10837 list_for_each_entry(pmu, &pmus, entry) {
10838 if (pmu->task_ctx_nr == ctxn)
10839 return pmu->pmu_cpu_context;
10845 static void free_pmu_context(struct pmu *pmu)
10848 * Static contexts such as perf_sw_context have a global lifetime
10849 * and may be shared between different PMUs. Avoid freeing them
10850 * when a single PMU is going away.
10852 if (pmu->task_ctx_nr > perf_invalid_context)
10855 free_percpu(pmu->pmu_cpu_context);
10859 * Let userspace know that this PMU supports address range filtering:
10861 static ssize_t nr_addr_filters_show(struct device *dev,
10862 struct device_attribute *attr,
10865 struct pmu *pmu = dev_get_drvdata(dev);
10867 return snprintf(page, PAGE_SIZE - 1, "%d\n", pmu->nr_addr_filters);
10869 DEVICE_ATTR_RO(nr_addr_filters);
10871 static struct idr pmu_idr;
10874 type_show(struct device *dev, struct device_attribute *attr, char *page)
10876 struct pmu *pmu = dev_get_drvdata(dev);
10878 return snprintf(page, PAGE_SIZE-1, "%d\n", pmu->type);
10880 static DEVICE_ATTR_RO(type);
10883 perf_event_mux_interval_ms_show(struct device *dev,
10884 struct device_attribute *attr,
10887 struct pmu *pmu = dev_get_drvdata(dev);
10889 return snprintf(page, PAGE_SIZE-1, "%d\n", pmu->hrtimer_interval_ms);
10892 static DEFINE_MUTEX(mux_interval_mutex);
10895 perf_event_mux_interval_ms_store(struct device *dev,
10896 struct device_attribute *attr,
10897 const char *buf, size_t count)
10899 struct pmu *pmu = dev_get_drvdata(dev);
10900 int timer, cpu, ret;
10902 ret = kstrtoint(buf, 0, &timer);
10909 /* same value, noting to do */
10910 if (timer == pmu->hrtimer_interval_ms)
10913 mutex_lock(&mux_interval_mutex);
10914 pmu->hrtimer_interval_ms = timer;
10916 /* update all cpuctx for this PMU */
10918 for_each_online_cpu(cpu) {
10919 struct perf_cpu_context *cpuctx;
10920 cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
10921 cpuctx->hrtimer_interval = ns_to_ktime(NSEC_PER_MSEC * timer);
10923 cpu_function_call(cpu,
10924 (remote_function_f)perf_mux_hrtimer_restart, cpuctx);
10926 cpus_read_unlock();
10927 mutex_unlock(&mux_interval_mutex);
10931 static DEVICE_ATTR_RW(perf_event_mux_interval_ms);
10933 static struct attribute *pmu_dev_attrs[] = {
10934 &dev_attr_type.attr,
10935 &dev_attr_perf_event_mux_interval_ms.attr,
10938 ATTRIBUTE_GROUPS(pmu_dev);
10940 static int pmu_bus_running;
10941 static struct bus_type pmu_bus = {
10942 .name = "event_source",
10943 .dev_groups = pmu_dev_groups,
10946 static void pmu_dev_release(struct device *dev)
10951 static int pmu_dev_alloc(struct pmu *pmu)
10955 pmu->dev = kzalloc(sizeof(struct device), GFP_KERNEL);
10959 pmu->dev->groups = pmu->attr_groups;
10960 device_initialize(pmu->dev);
10961 ret = dev_set_name(pmu->dev, "%s", pmu->name);
10965 dev_set_drvdata(pmu->dev, pmu);
10966 pmu->dev->bus = &pmu_bus;
10967 pmu->dev->release = pmu_dev_release;
10968 ret = device_add(pmu->dev);
10972 /* For PMUs with address filters, throw in an extra attribute: */
10973 if (pmu->nr_addr_filters)
10974 ret = device_create_file(pmu->dev, &dev_attr_nr_addr_filters);
10979 if (pmu->attr_update)
10980 ret = sysfs_update_groups(&pmu->dev->kobj, pmu->attr_update);
10989 device_del(pmu->dev);
10992 put_device(pmu->dev);
10996 static struct lock_class_key cpuctx_mutex;
10997 static struct lock_class_key cpuctx_lock;
10999 int perf_pmu_register(struct pmu *pmu, const char *name, int type)
11001 int cpu, ret, max = PERF_TYPE_MAX;
11003 mutex_lock(&pmus_lock);
11005 pmu->pmu_disable_count = alloc_percpu(int);
11006 if (!pmu->pmu_disable_count)
11014 if (type != PERF_TYPE_SOFTWARE) {
11018 ret = idr_alloc(&pmu_idr, pmu, max, 0, GFP_KERNEL);
11022 WARN_ON(type >= 0 && ret != type);
11028 if (pmu_bus_running) {
11029 ret = pmu_dev_alloc(pmu);
11035 if (pmu->task_ctx_nr == perf_hw_context) {
11036 static int hw_context_taken = 0;
11039 * Other than systems with heterogeneous CPUs, it never makes
11040 * sense for two PMUs to share perf_hw_context. PMUs which are
11041 * uncore must use perf_invalid_context.
11043 if (WARN_ON_ONCE(hw_context_taken &&
11044 !(pmu->capabilities & PERF_PMU_CAP_HETEROGENEOUS_CPUS)))
11045 pmu->task_ctx_nr = perf_invalid_context;
11047 hw_context_taken = 1;
11050 pmu->pmu_cpu_context = find_pmu_context(pmu->task_ctx_nr);
11051 if (pmu->pmu_cpu_context)
11052 goto got_cpu_context;
11055 pmu->pmu_cpu_context = alloc_percpu(struct perf_cpu_context);
11056 if (!pmu->pmu_cpu_context)
11059 for_each_possible_cpu(cpu) {
11060 struct perf_cpu_context *cpuctx;
11062 cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
11063 __perf_event_init_context(&cpuctx->ctx);
11064 lockdep_set_class(&cpuctx->ctx.mutex, &cpuctx_mutex);
11065 lockdep_set_class(&cpuctx->ctx.lock, &cpuctx_lock);
11066 cpuctx->ctx.pmu = pmu;
11067 cpuctx->online = cpumask_test_cpu(cpu, perf_online_mask);
11069 __perf_mux_hrtimer_init(cpuctx, cpu);
11071 cpuctx->heap_size = ARRAY_SIZE(cpuctx->heap_default);
11072 cpuctx->heap = cpuctx->heap_default;
11076 if (!pmu->start_txn) {
11077 if (pmu->pmu_enable) {
11079 * If we have pmu_enable/pmu_disable calls, install
11080 * transaction stubs that use that to try and batch
11081 * hardware accesses.
11083 pmu->start_txn = perf_pmu_start_txn;
11084 pmu->commit_txn = perf_pmu_commit_txn;
11085 pmu->cancel_txn = perf_pmu_cancel_txn;
11087 pmu->start_txn = perf_pmu_nop_txn;
11088 pmu->commit_txn = perf_pmu_nop_int;
11089 pmu->cancel_txn = perf_pmu_nop_void;
11093 if (!pmu->pmu_enable) {
11094 pmu->pmu_enable = perf_pmu_nop_void;
11095 pmu->pmu_disable = perf_pmu_nop_void;
11098 if (!pmu->check_period)
11099 pmu->check_period = perf_event_nop_int;
11101 if (!pmu->event_idx)
11102 pmu->event_idx = perf_event_idx_default;
11105 * Ensure the TYPE_SOFTWARE PMUs are at the head of the list,
11106 * since these cannot be in the IDR. This way the linear search
11107 * is fast, provided a valid software event is provided.
11109 if (type == PERF_TYPE_SOFTWARE || !name)
11110 list_add_rcu(&pmu->entry, &pmus);
11112 list_add_tail_rcu(&pmu->entry, &pmus);
11114 atomic_set(&pmu->exclusive_cnt, 0);
11117 mutex_unlock(&pmus_lock);
11122 device_del(pmu->dev);
11123 put_device(pmu->dev);
11126 if (pmu->type != PERF_TYPE_SOFTWARE)
11127 idr_remove(&pmu_idr, pmu->type);
11130 free_percpu(pmu->pmu_disable_count);
11133 EXPORT_SYMBOL_GPL(perf_pmu_register);
11135 void perf_pmu_unregister(struct pmu *pmu)
11137 mutex_lock(&pmus_lock);
11138 list_del_rcu(&pmu->entry);
11141 * We dereference the pmu list under both SRCU and regular RCU, so
11142 * synchronize against both of those.
11144 synchronize_srcu(&pmus_srcu);
11147 free_percpu(pmu->pmu_disable_count);
11148 if (pmu->type != PERF_TYPE_SOFTWARE)
11149 idr_remove(&pmu_idr, pmu->type);
11150 if (pmu_bus_running) {
11151 if (pmu->nr_addr_filters)
11152 device_remove_file(pmu->dev, &dev_attr_nr_addr_filters);
11153 device_del(pmu->dev);
11154 put_device(pmu->dev);
11156 free_pmu_context(pmu);
11157 mutex_unlock(&pmus_lock);
11159 EXPORT_SYMBOL_GPL(perf_pmu_unregister);
11161 static inline bool has_extended_regs(struct perf_event *event)
11163 return (event->attr.sample_regs_user & PERF_REG_EXTENDED_MASK) ||
11164 (event->attr.sample_regs_intr & PERF_REG_EXTENDED_MASK);
11167 static int perf_try_init_event(struct pmu *pmu, struct perf_event *event)
11169 struct perf_event_context *ctx = NULL;
11172 if (!try_module_get(pmu->module))
11176 * A number of pmu->event_init() methods iterate the sibling_list to,
11177 * for example, validate if the group fits on the PMU. Therefore,
11178 * if this is a sibling event, acquire the ctx->mutex to protect
11179 * the sibling_list.
11181 if (event->group_leader != event && pmu->task_ctx_nr != perf_sw_context) {
11183 * This ctx->mutex can nest when we're called through
11184 * inheritance. See the perf_event_ctx_lock_nested() comment.
11186 ctx = perf_event_ctx_lock_nested(event->group_leader,
11187 SINGLE_DEPTH_NESTING);
11192 ret = pmu->event_init(event);
11195 perf_event_ctx_unlock(event->group_leader, ctx);
11198 if (!(pmu->capabilities & PERF_PMU_CAP_EXTENDED_REGS) &&
11199 has_extended_regs(event))
11202 if (pmu->capabilities & PERF_PMU_CAP_NO_EXCLUDE &&
11203 event_has_any_exclude_flag(event))
11206 if (ret && event->destroy)
11207 event->destroy(event);
11211 module_put(pmu->module);
11216 static struct pmu *perf_init_event(struct perf_event *event)
11218 bool extended_type = false;
11219 int idx, type, ret;
11222 idx = srcu_read_lock(&pmus_srcu);
11224 /* Try parent's PMU first: */
11225 if (event->parent && event->parent->pmu) {
11226 pmu = event->parent->pmu;
11227 ret = perf_try_init_event(pmu, event);
11233 * PERF_TYPE_HARDWARE and PERF_TYPE_HW_CACHE
11234 * are often aliases for PERF_TYPE_RAW.
11236 type = event->attr.type;
11237 if (type == PERF_TYPE_HARDWARE || type == PERF_TYPE_HW_CACHE) {
11238 type = event->attr.config >> PERF_PMU_TYPE_SHIFT;
11240 type = PERF_TYPE_RAW;
11242 extended_type = true;
11243 event->attr.config &= PERF_HW_EVENT_MASK;
11249 pmu = idr_find(&pmu_idr, type);
11252 if (event->attr.type != type && type != PERF_TYPE_RAW &&
11253 !(pmu->capabilities & PERF_PMU_CAP_EXTENDED_HW_TYPE))
11256 ret = perf_try_init_event(pmu, event);
11257 if (ret == -ENOENT && event->attr.type != type && !extended_type) {
11258 type = event->attr.type;
11263 pmu = ERR_PTR(ret);
11268 list_for_each_entry_rcu(pmu, &pmus, entry, lockdep_is_held(&pmus_srcu)) {
11269 ret = perf_try_init_event(pmu, event);
11273 if (ret != -ENOENT) {
11274 pmu = ERR_PTR(ret);
11279 pmu = ERR_PTR(-ENOENT);
11281 srcu_read_unlock(&pmus_srcu, idx);
11286 static void attach_sb_event(struct perf_event *event)
11288 struct pmu_event_list *pel = per_cpu_ptr(&pmu_sb_events, event->cpu);
11290 raw_spin_lock(&pel->lock);
11291 list_add_rcu(&event->sb_list, &pel->list);
11292 raw_spin_unlock(&pel->lock);
11296 * We keep a list of all !task (and therefore per-cpu) events
11297 * that need to receive side-band records.
11299 * This avoids having to scan all the various PMU per-cpu contexts
11300 * looking for them.
11302 static void account_pmu_sb_event(struct perf_event *event)
11304 if (is_sb_event(event))
11305 attach_sb_event(event);
11308 static void account_event_cpu(struct perf_event *event, int cpu)
11313 if (is_cgroup_event(event))
11314 atomic_inc(&per_cpu(perf_cgroup_events, cpu));
11317 /* Freq events need the tick to stay alive (see perf_event_task_tick). */
11318 static void account_freq_event_nohz(void)
11320 #ifdef CONFIG_NO_HZ_FULL
11321 /* Lock so we don't race with concurrent unaccount */
11322 spin_lock(&nr_freq_lock);
11323 if (atomic_inc_return(&nr_freq_events) == 1)
11324 tick_nohz_dep_set(TICK_DEP_BIT_PERF_EVENTS);
11325 spin_unlock(&nr_freq_lock);
11329 static void account_freq_event(void)
11331 if (tick_nohz_full_enabled())
11332 account_freq_event_nohz();
11334 atomic_inc(&nr_freq_events);
11338 static void account_event(struct perf_event *event)
11345 if (event->attach_state & (PERF_ATTACH_TASK | PERF_ATTACH_SCHED_CB))
11347 if (event->attr.mmap || event->attr.mmap_data)
11348 atomic_inc(&nr_mmap_events);
11349 if (event->attr.build_id)
11350 atomic_inc(&nr_build_id_events);
11351 if (event->attr.comm)
11352 atomic_inc(&nr_comm_events);
11353 if (event->attr.namespaces)
11354 atomic_inc(&nr_namespaces_events);
11355 if (event->attr.cgroup)
11356 atomic_inc(&nr_cgroup_events);
11357 if (event->attr.task)
11358 atomic_inc(&nr_task_events);
11359 if (event->attr.freq)
11360 account_freq_event();
11361 if (event->attr.context_switch) {
11362 atomic_inc(&nr_switch_events);
11365 if (has_branch_stack(event))
11367 if (is_cgroup_event(event))
11369 if (event->attr.ksymbol)
11370 atomic_inc(&nr_ksymbol_events);
11371 if (event->attr.bpf_event)
11372 atomic_inc(&nr_bpf_events);
11373 if (event->attr.text_poke)
11374 atomic_inc(&nr_text_poke_events);
11378 * We need the mutex here because static_branch_enable()
11379 * must complete *before* the perf_sched_count increment
11382 if (atomic_inc_not_zero(&perf_sched_count))
11385 mutex_lock(&perf_sched_mutex);
11386 if (!atomic_read(&perf_sched_count)) {
11387 static_branch_enable(&perf_sched_events);
11389 * Guarantee that all CPUs observe they key change and
11390 * call the perf scheduling hooks before proceeding to
11391 * install events that need them.
11396 * Now that we have waited for the sync_sched(), allow further
11397 * increments to by-pass the mutex.
11399 atomic_inc(&perf_sched_count);
11400 mutex_unlock(&perf_sched_mutex);
11404 account_event_cpu(event, event->cpu);
11406 account_pmu_sb_event(event);
11410 * Allocate and initialize an event structure
11412 static struct perf_event *
11413 perf_event_alloc(struct perf_event_attr *attr, int cpu,
11414 struct task_struct *task,
11415 struct perf_event *group_leader,
11416 struct perf_event *parent_event,
11417 perf_overflow_handler_t overflow_handler,
11418 void *context, int cgroup_fd)
11421 struct perf_event *event;
11422 struct hw_perf_event *hwc;
11423 long err = -EINVAL;
11426 if ((unsigned)cpu >= nr_cpu_ids) {
11427 if (!task || cpu != -1)
11428 return ERR_PTR(-EINVAL);
11430 if (attr->sigtrap && !task) {
11431 /* Requires a task: avoid signalling random tasks. */
11432 return ERR_PTR(-EINVAL);
11435 node = (cpu >= 0) ? cpu_to_node(cpu) : -1;
11436 event = kmem_cache_alloc_node(perf_event_cache, GFP_KERNEL | __GFP_ZERO,
11439 return ERR_PTR(-ENOMEM);
11442 * Single events are their own group leaders, with an
11443 * empty sibling list:
11446 group_leader = event;
11448 mutex_init(&event->child_mutex);
11449 INIT_LIST_HEAD(&event->child_list);
11451 INIT_LIST_HEAD(&event->event_entry);
11452 INIT_LIST_HEAD(&event->sibling_list);
11453 INIT_LIST_HEAD(&event->active_list);
11454 init_event_group(event);
11455 INIT_LIST_HEAD(&event->rb_entry);
11456 INIT_LIST_HEAD(&event->active_entry);
11457 INIT_LIST_HEAD(&event->addr_filters.list);
11458 INIT_HLIST_NODE(&event->hlist_entry);
11461 init_waitqueue_head(&event->waitq);
11462 event->pending_disable = -1;
11463 init_irq_work(&event->pending, perf_pending_event);
11465 mutex_init(&event->mmap_mutex);
11466 raw_spin_lock_init(&event->addr_filters.lock);
11468 atomic_long_set(&event->refcount, 1);
11470 event->attr = *attr;
11471 event->group_leader = group_leader;
11475 event->parent = parent_event;
11477 event->ns = get_pid_ns(task_active_pid_ns(current));
11478 event->id = atomic64_inc_return(&perf_event_id);
11480 event->state = PERF_EVENT_STATE_INACTIVE;
11482 if (event->attr.sigtrap)
11483 atomic_set(&event->event_limit, 1);
11486 event->attach_state = PERF_ATTACH_TASK;
11488 * XXX pmu::event_init needs to know what task to account to
11489 * and we cannot use the ctx information because we need the
11490 * pmu before we get a ctx.
11492 event->hw.target = get_task_struct(task);
11495 event->clock = &local_clock;
11497 event->clock = parent_event->clock;
11499 if (!overflow_handler && parent_event) {
11500 overflow_handler = parent_event->overflow_handler;
11501 context = parent_event->overflow_handler_context;
11502 #if defined(CONFIG_BPF_SYSCALL) && defined(CONFIG_EVENT_TRACING)
11503 if (overflow_handler == bpf_overflow_handler) {
11504 struct bpf_prog *prog = parent_event->prog;
11506 bpf_prog_inc(prog);
11507 event->prog = prog;
11508 event->orig_overflow_handler =
11509 parent_event->orig_overflow_handler;
11514 if (overflow_handler) {
11515 event->overflow_handler = overflow_handler;
11516 event->overflow_handler_context = context;
11517 } else if (is_write_backward(event)){
11518 event->overflow_handler = perf_event_output_backward;
11519 event->overflow_handler_context = NULL;
11521 event->overflow_handler = perf_event_output_forward;
11522 event->overflow_handler_context = NULL;
11525 perf_event__state_init(event);
11530 hwc->sample_period = attr->sample_period;
11531 if (attr->freq && attr->sample_freq)
11532 hwc->sample_period = 1;
11533 hwc->last_period = hwc->sample_period;
11535 local64_set(&hwc->period_left, hwc->sample_period);
11538 * We currently do not support PERF_SAMPLE_READ on inherited events.
11539 * See perf_output_read().
11541 if (attr->inherit && (attr->sample_type & PERF_SAMPLE_READ))
11544 if (!has_branch_stack(event))
11545 event->attr.branch_sample_type = 0;
11547 pmu = perf_init_event(event);
11549 err = PTR_ERR(pmu);
11554 * Disallow uncore-cgroup events, they don't make sense as the cgroup will
11555 * be different on other CPUs in the uncore mask.
11557 if (pmu->task_ctx_nr == perf_invalid_context && cgroup_fd != -1) {
11562 if (event->attr.aux_output &&
11563 !(pmu->capabilities & PERF_PMU_CAP_AUX_OUTPUT)) {
11568 if (cgroup_fd != -1) {
11569 err = perf_cgroup_connect(cgroup_fd, event, attr, group_leader);
11574 err = exclusive_event_init(event);
11578 if (has_addr_filter(event)) {
11579 event->addr_filter_ranges = kcalloc(pmu->nr_addr_filters,
11580 sizeof(struct perf_addr_filter_range),
11582 if (!event->addr_filter_ranges) {
11588 * Clone the parent's vma offsets: they are valid until exec()
11589 * even if the mm is not shared with the parent.
11591 if (event->parent) {
11592 struct perf_addr_filters_head *ifh = perf_event_addr_filters(event);
11594 raw_spin_lock_irq(&ifh->lock);
11595 memcpy(event->addr_filter_ranges,
11596 event->parent->addr_filter_ranges,
11597 pmu->nr_addr_filters * sizeof(struct perf_addr_filter_range));
11598 raw_spin_unlock_irq(&ifh->lock);
11601 /* force hw sync on the address filters */
11602 event->addr_filters_gen = 1;
11605 if (!event->parent) {
11606 if (event->attr.sample_type & PERF_SAMPLE_CALLCHAIN) {
11607 err = get_callchain_buffers(attr->sample_max_stack);
11609 goto err_addr_filters;
11613 err = security_perf_event_alloc(event);
11615 goto err_callchain_buffer;
11617 /* symmetric to unaccount_event() in _free_event() */
11618 account_event(event);
11622 err_callchain_buffer:
11623 if (!event->parent) {
11624 if (event->attr.sample_type & PERF_SAMPLE_CALLCHAIN)
11625 put_callchain_buffers();
11628 kfree(event->addr_filter_ranges);
11631 exclusive_event_destroy(event);
11634 if (is_cgroup_event(event))
11635 perf_detach_cgroup(event);
11636 if (event->destroy)
11637 event->destroy(event);
11638 module_put(pmu->module);
11641 put_pid_ns(event->ns);
11642 if (event->hw.target)
11643 put_task_struct(event->hw.target);
11644 kmem_cache_free(perf_event_cache, event);
11646 return ERR_PTR(err);
11649 static int perf_copy_attr(struct perf_event_attr __user *uattr,
11650 struct perf_event_attr *attr)
11655 /* Zero the full structure, so that a short copy will be nice. */
11656 memset(attr, 0, sizeof(*attr));
11658 ret = get_user(size, &uattr->size);
11662 /* ABI compatibility quirk: */
11664 size = PERF_ATTR_SIZE_VER0;
11665 if (size < PERF_ATTR_SIZE_VER0 || size > PAGE_SIZE)
11668 ret = copy_struct_from_user(attr, sizeof(*attr), uattr, size);
11677 if (attr->__reserved_1 || attr->__reserved_2 || attr->__reserved_3)
11680 if (attr->sample_type & ~(PERF_SAMPLE_MAX-1))
11683 if (attr->read_format & ~(PERF_FORMAT_MAX-1))
11686 if (attr->sample_type & PERF_SAMPLE_BRANCH_STACK) {
11687 u64 mask = attr->branch_sample_type;
11689 /* only using defined bits */
11690 if (mask & ~(PERF_SAMPLE_BRANCH_MAX-1))
11693 /* at least one branch bit must be set */
11694 if (!(mask & ~PERF_SAMPLE_BRANCH_PLM_ALL))
11697 /* propagate priv level, when not set for branch */
11698 if (!(mask & PERF_SAMPLE_BRANCH_PLM_ALL)) {
11700 /* exclude_kernel checked on syscall entry */
11701 if (!attr->exclude_kernel)
11702 mask |= PERF_SAMPLE_BRANCH_KERNEL;
11704 if (!attr->exclude_user)
11705 mask |= PERF_SAMPLE_BRANCH_USER;
11707 if (!attr->exclude_hv)
11708 mask |= PERF_SAMPLE_BRANCH_HV;
11710 * adjust user setting (for HW filter setup)
11712 attr->branch_sample_type = mask;
11714 /* privileged levels capture (kernel, hv): check permissions */
11715 if (mask & PERF_SAMPLE_BRANCH_PERM_PLM) {
11716 ret = perf_allow_kernel(attr);
11722 if (attr->sample_type & PERF_SAMPLE_REGS_USER) {
11723 ret = perf_reg_validate(attr->sample_regs_user);
11728 if (attr->sample_type & PERF_SAMPLE_STACK_USER) {
11729 if (!arch_perf_have_user_stack_dump())
11733 * We have __u32 type for the size, but so far
11734 * we can only use __u16 as maximum due to the
11735 * __u16 sample size limit.
11737 if (attr->sample_stack_user >= USHRT_MAX)
11739 else if (!IS_ALIGNED(attr->sample_stack_user, sizeof(u64)))
11743 if (!attr->sample_max_stack)
11744 attr->sample_max_stack = sysctl_perf_event_max_stack;
11746 if (attr->sample_type & PERF_SAMPLE_REGS_INTR)
11747 ret = perf_reg_validate(attr->sample_regs_intr);
11749 #ifndef CONFIG_CGROUP_PERF
11750 if (attr->sample_type & PERF_SAMPLE_CGROUP)
11753 if ((attr->sample_type & PERF_SAMPLE_WEIGHT) &&
11754 (attr->sample_type & PERF_SAMPLE_WEIGHT_STRUCT))
11757 if (!attr->inherit && attr->inherit_thread)
11760 if (attr->remove_on_exec && attr->enable_on_exec)
11763 if (attr->sigtrap && !attr->remove_on_exec)
11770 put_user(sizeof(*attr), &uattr->size);
11776 perf_event_set_output(struct perf_event *event, struct perf_event *output_event)
11778 struct perf_buffer *rb = NULL;
11784 /* don't allow circular references */
11785 if (event == output_event)
11789 * Don't allow cross-cpu buffers
11791 if (output_event->cpu != event->cpu)
11795 * If its not a per-cpu rb, it must be the same task.
11797 if (output_event->cpu == -1 && output_event->ctx != event->ctx)
11801 * Mixing clocks in the same buffer is trouble you don't need.
11803 if (output_event->clock != event->clock)
11807 * Either writing ring buffer from beginning or from end.
11808 * Mixing is not allowed.
11810 if (is_write_backward(output_event) != is_write_backward(event))
11814 * If both events generate aux data, they must be on the same PMU
11816 if (has_aux(event) && has_aux(output_event) &&
11817 event->pmu != output_event->pmu)
11821 mutex_lock(&event->mmap_mutex);
11822 /* Can't redirect output if we've got an active mmap() */
11823 if (atomic_read(&event->mmap_count))
11826 if (output_event) {
11827 /* get the rb we want to redirect to */
11828 rb = ring_buffer_get(output_event);
11833 ring_buffer_attach(event, rb);
11837 mutex_unlock(&event->mmap_mutex);
11843 static void mutex_lock_double(struct mutex *a, struct mutex *b)
11849 mutex_lock_nested(b, SINGLE_DEPTH_NESTING);
11852 static int perf_event_set_clock(struct perf_event *event, clockid_t clk_id)
11854 bool nmi_safe = false;
11857 case CLOCK_MONOTONIC:
11858 event->clock = &ktime_get_mono_fast_ns;
11862 case CLOCK_MONOTONIC_RAW:
11863 event->clock = &ktime_get_raw_fast_ns;
11867 case CLOCK_REALTIME:
11868 event->clock = &ktime_get_real_ns;
11871 case CLOCK_BOOTTIME:
11872 event->clock = &ktime_get_boottime_ns;
11876 event->clock = &ktime_get_clocktai_ns;
11883 if (!nmi_safe && !(event->pmu->capabilities & PERF_PMU_CAP_NO_NMI))
11890 * Variation on perf_event_ctx_lock_nested(), except we take two context
11893 static struct perf_event_context *
11894 __perf_event_ctx_lock_double(struct perf_event *group_leader,
11895 struct perf_event_context *ctx)
11897 struct perf_event_context *gctx;
11901 gctx = READ_ONCE(group_leader->ctx);
11902 if (!refcount_inc_not_zero(&gctx->refcount)) {
11908 mutex_lock_double(&gctx->mutex, &ctx->mutex);
11910 if (group_leader->ctx != gctx) {
11911 mutex_unlock(&ctx->mutex);
11912 mutex_unlock(&gctx->mutex);
11921 * sys_perf_event_open - open a performance event, associate it to a task/cpu
11923 * @attr_uptr: event_id type attributes for monitoring/sampling
11926 * @group_fd: group leader event fd
11928 SYSCALL_DEFINE5(perf_event_open,
11929 struct perf_event_attr __user *, attr_uptr,
11930 pid_t, pid, int, cpu, int, group_fd, unsigned long, flags)
11932 struct perf_event *group_leader = NULL, *output_event = NULL;
11933 struct perf_event *event, *sibling;
11934 struct perf_event_attr attr;
11935 struct perf_event_context *ctx, *gctx;
11936 struct file *event_file = NULL;
11937 struct fd group = {NULL, 0};
11938 struct task_struct *task = NULL;
11941 int move_group = 0;
11943 int f_flags = O_RDWR;
11944 int cgroup_fd = -1;
11946 /* for future expandability... */
11947 if (flags & ~PERF_FLAG_ALL)
11950 /* Do we allow access to perf_event_open(2) ? */
11951 err = security_perf_event_open(&attr, PERF_SECURITY_OPEN);
11955 err = perf_copy_attr(attr_uptr, &attr);
11959 if (!attr.exclude_kernel) {
11960 err = perf_allow_kernel(&attr);
11965 if (attr.namespaces) {
11966 if (!perfmon_capable())
11971 if (attr.sample_freq > sysctl_perf_event_sample_rate)
11974 if (attr.sample_period & (1ULL << 63))
11978 /* Only privileged users can get physical addresses */
11979 if ((attr.sample_type & PERF_SAMPLE_PHYS_ADDR)) {
11980 err = perf_allow_kernel(&attr);
11985 /* REGS_INTR can leak data, lockdown must prevent this */
11986 if (attr.sample_type & PERF_SAMPLE_REGS_INTR) {
11987 err = security_locked_down(LOCKDOWN_PERF);
11993 * In cgroup mode, the pid argument is used to pass the fd
11994 * opened to the cgroup directory in cgroupfs. The cpu argument
11995 * designates the cpu on which to monitor threads from that
11998 if ((flags & PERF_FLAG_PID_CGROUP) && (pid == -1 || cpu == -1))
12001 if (flags & PERF_FLAG_FD_CLOEXEC)
12002 f_flags |= O_CLOEXEC;
12004 event_fd = get_unused_fd_flags(f_flags);
12008 if (group_fd != -1) {
12009 err = perf_fget_light(group_fd, &group);
12012 group_leader = group.file->private_data;
12013 if (flags & PERF_FLAG_FD_OUTPUT)
12014 output_event = group_leader;
12015 if (flags & PERF_FLAG_FD_NO_GROUP)
12016 group_leader = NULL;
12019 if (pid != -1 && !(flags & PERF_FLAG_PID_CGROUP)) {
12020 task = find_lively_task_by_vpid(pid);
12021 if (IS_ERR(task)) {
12022 err = PTR_ERR(task);
12027 if (task && group_leader &&
12028 group_leader->attr.inherit != attr.inherit) {
12033 if (flags & PERF_FLAG_PID_CGROUP)
12036 event = perf_event_alloc(&attr, cpu, task, group_leader, NULL,
12037 NULL, NULL, cgroup_fd);
12038 if (IS_ERR(event)) {
12039 err = PTR_ERR(event);
12043 if (is_sampling_event(event)) {
12044 if (event->pmu->capabilities & PERF_PMU_CAP_NO_INTERRUPT) {
12051 * Special case software events and allow them to be part of
12052 * any hardware group.
12056 if (attr.use_clockid) {
12057 err = perf_event_set_clock(event, attr.clockid);
12062 if (pmu->task_ctx_nr == perf_sw_context)
12063 event->event_caps |= PERF_EV_CAP_SOFTWARE;
12065 if (group_leader) {
12066 if (is_software_event(event) &&
12067 !in_software_context(group_leader)) {
12069 * If the event is a sw event, but the group_leader
12070 * is on hw context.
12072 * Allow the addition of software events to hw
12073 * groups, this is safe because software events
12074 * never fail to schedule.
12076 pmu = group_leader->ctx->pmu;
12077 } else if (!is_software_event(event) &&
12078 is_software_event(group_leader) &&
12079 (group_leader->group_caps & PERF_EV_CAP_SOFTWARE)) {
12081 * In case the group is a pure software group, and we
12082 * try to add a hardware event, move the whole group to
12083 * the hardware context.
12090 * Get the target context (task or percpu):
12092 ctx = find_get_context(pmu, task, event);
12094 err = PTR_ERR(ctx);
12099 * Look up the group leader (we will attach this event to it):
12101 if (group_leader) {
12105 * Do not allow a recursive hierarchy (this new sibling
12106 * becoming part of another group-sibling):
12108 if (group_leader->group_leader != group_leader)
12111 /* All events in a group should have the same clock */
12112 if (group_leader->clock != event->clock)
12116 * Make sure we're both events for the same CPU;
12117 * grouping events for different CPUs is broken; since
12118 * you can never concurrently schedule them anyhow.
12120 if (group_leader->cpu != event->cpu)
12124 * Make sure we're both on the same task, or both
12127 if (group_leader->ctx->task != ctx->task)
12131 * Do not allow to attach to a group in a different task
12132 * or CPU context. If we're moving SW events, we'll fix
12133 * this up later, so allow that.
12135 if (!move_group && group_leader->ctx != ctx)
12139 * Only a group leader can be exclusive or pinned
12141 if (attr.exclusive || attr.pinned)
12145 if (output_event) {
12146 err = perf_event_set_output(event, output_event);
12151 event_file = anon_inode_getfile("[perf_event]", &perf_fops, event,
12153 if (IS_ERR(event_file)) {
12154 err = PTR_ERR(event_file);
12160 err = down_read_interruptible(&task->signal->exec_update_lock);
12165 * Preserve ptrace permission check for backwards compatibility.
12167 * We must hold exec_update_lock across this and any potential
12168 * perf_install_in_context() call for this new event to
12169 * serialize against exec() altering our credentials (and the
12170 * perf_event_exit_task() that could imply).
12173 if (!perfmon_capable() && !ptrace_may_access(task, PTRACE_MODE_READ_REALCREDS))
12178 gctx = __perf_event_ctx_lock_double(group_leader, ctx);
12180 if (gctx->task == TASK_TOMBSTONE) {
12186 * Check if we raced against another sys_perf_event_open() call
12187 * moving the software group underneath us.
12189 if (!(group_leader->group_caps & PERF_EV_CAP_SOFTWARE)) {
12191 * If someone moved the group out from under us, check
12192 * if this new event wound up on the same ctx, if so
12193 * its the regular !move_group case, otherwise fail.
12199 perf_event_ctx_unlock(group_leader, gctx);
12205 * Failure to create exclusive events returns -EBUSY.
12208 if (!exclusive_event_installable(group_leader, ctx))
12211 for_each_sibling_event(sibling, group_leader) {
12212 if (!exclusive_event_installable(sibling, ctx))
12216 mutex_lock(&ctx->mutex);
12219 if (ctx->task == TASK_TOMBSTONE) {
12224 if (!perf_event_validate_size(event)) {
12231 * Check if the @cpu we're creating an event for is online.
12233 * We use the perf_cpu_context::ctx::mutex to serialize against
12234 * the hotplug notifiers. See perf_event_{init,exit}_cpu().
12236 struct perf_cpu_context *cpuctx =
12237 container_of(ctx, struct perf_cpu_context, ctx);
12239 if (!cpuctx->online) {
12245 if (perf_need_aux_event(event) && !perf_get_aux_event(event, group_leader)) {
12251 * Must be under the same ctx::mutex as perf_install_in_context(),
12252 * because we need to serialize with concurrent event creation.
12254 if (!exclusive_event_installable(event, ctx)) {
12259 WARN_ON_ONCE(ctx->parent_ctx);
12262 * This is the point on no return; we cannot fail hereafter. This is
12263 * where we start modifying current state.
12268 * See perf_event_ctx_lock() for comments on the details
12269 * of swizzling perf_event::ctx.
12271 perf_remove_from_context(group_leader, 0);
12274 for_each_sibling_event(sibling, group_leader) {
12275 perf_remove_from_context(sibling, 0);
12280 * Wait for everybody to stop referencing the events through
12281 * the old lists, before installing it on new lists.
12286 * Install the group siblings before the group leader.
12288 * Because a group leader will try and install the entire group
12289 * (through the sibling list, which is still in-tact), we can
12290 * end up with siblings installed in the wrong context.
12292 * By installing siblings first we NO-OP because they're not
12293 * reachable through the group lists.
12295 for_each_sibling_event(sibling, group_leader) {
12296 perf_event__state_init(sibling);
12297 perf_install_in_context(ctx, sibling, sibling->cpu);
12302 * Removing from the context ends up with disabled
12303 * event. What we want here is event in the initial
12304 * startup state, ready to be add into new context.
12306 perf_event__state_init(group_leader);
12307 perf_install_in_context(ctx, group_leader, group_leader->cpu);
12312 * Precalculate sample_data sizes; do while holding ctx::mutex such
12313 * that we're serialized against further additions and before
12314 * perf_install_in_context() which is the point the event is active and
12315 * can use these values.
12317 perf_event__header_size(event);
12318 perf_event__id_header_size(event);
12320 event->owner = current;
12322 perf_install_in_context(ctx, event, event->cpu);
12323 perf_unpin_context(ctx);
12326 perf_event_ctx_unlock(group_leader, gctx);
12327 mutex_unlock(&ctx->mutex);
12330 up_read(&task->signal->exec_update_lock);
12331 put_task_struct(task);
12334 mutex_lock(¤t->perf_event_mutex);
12335 list_add_tail(&event->owner_entry, ¤t->perf_event_list);
12336 mutex_unlock(¤t->perf_event_mutex);
12339 * Drop the reference on the group_event after placing the
12340 * new event on the sibling_list. This ensures destruction
12341 * of the group leader will find the pointer to itself in
12342 * perf_group_detach().
12345 fd_install(event_fd, event_file);
12350 perf_event_ctx_unlock(group_leader, gctx);
12351 mutex_unlock(&ctx->mutex);
12354 up_read(&task->signal->exec_update_lock);
12358 perf_unpin_context(ctx);
12362 * If event_file is set, the fput() above will have called ->release()
12363 * and that will take care of freeing the event.
12369 put_task_struct(task);
12373 put_unused_fd(event_fd);
12378 * perf_event_create_kernel_counter
12380 * @attr: attributes of the counter to create
12381 * @cpu: cpu in which the counter is bound
12382 * @task: task to profile (NULL for percpu)
12384 struct perf_event *
12385 perf_event_create_kernel_counter(struct perf_event_attr *attr, int cpu,
12386 struct task_struct *task,
12387 perf_overflow_handler_t overflow_handler,
12390 struct perf_event_context *ctx;
12391 struct perf_event *event;
12395 * Grouping is not supported for kernel events, neither is 'AUX',
12396 * make sure the caller's intentions are adjusted.
12398 if (attr->aux_output)
12399 return ERR_PTR(-EINVAL);
12401 event = perf_event_alloc(attr, cpu, task, NULL, NULL,
12402 overflow_handler, context, -1);
12403 if (IS_ERR(event)) {
12404 err = PTR_ERR(event);
12408 /* Mark owner so we could distinguish it from user events. */
12409 event->owner = TASK_TOMBSTONE;
12412 * Get the target context (task or percpu):
12414 ctx = find_get_context(event->pmu, task, event);
12416 err = PTR_ERR(ctx);
12420 WARN_ON_ONCE(ctx->parent_ctx);
12421 mutex_lock(&ctx->mutex);
12422 if (ctx->task == TASK_TOMBSTONE) {
12429 * Check if the @cpu we're creating an event for is online.
12431 * We use the perf_cpu_context::ctx::mutex to serialize against
12432 * the hotplug notifiers. See perf_event_{init,exit}_cpu().
12434 struct perf_cpu_context *cpuctx =
12435 container_of(ctx, struct perf_cpu_context, ctx);
12436 if (!cpuctx->online) {
12442 if (!exclusive_event_installable(event, ctx)) {
12447 perf_install_in_context(ctx, event, event->cpu);
12448 perf_unpin_context(ctx);
12449 mutex_unlock(&ctx->mutex);
12454 mutex_unlock(&ctx->mutex);
12455 perf_unpin_context(ctx);
12460 return ERR_PTR(err);
12462 EXPORT_SYMBOL_GPL(perf_event_create_kernel_counter);
12464 void perf_pmu_migrate_context(struct pmu *pmu, int src_cpu, int dst_cpu)
12466 struct perf_event_context *src_ctx;
12467 struct perf_event_context *dst_ctx;
12468 struct perf_event *event, *tmp;
12471 src_ctx = &per_cpu_ptr(pmu->pmu_cpu_context, src_cpu)->ctx;
12472 dst_ctx = &per_cpu_ptr(pmu->pmu_cpu_context, dst_cpu)->ctx;
12475 * See perf_event_ctx_lock() for comments on the details
12476 * of swizzling perf_event::ctx.
12478 mutex_lock_double(&src_ctx->mutex, &dst_ctx->mutex);
12479 list_for_each_entry_safe(event, tmp, &src_ctx->event_list,
12481 perf_remove_from_context(event, 0);
12482 unaccount_event_cpu(event, src_cpu);
12484 list_add(&event->migrate_entry, &events);
12488 * Wait for the events to quiesce before re-instating them.
12493 * Re-instate events in 2 passes.
12495 * Skip over group leaders and only install siblings on this first
12496 * pass, siblings will not get enabled without a leader, however a
12497 * leader will enable its siblings, even if those are still on the old
12500 list_for_each_entry_safe(event, tmp, &events, migrate_entry) {
12501 if (event->group_leader == event)
12504 list_del(&event->migrate_entry);
12505 if (event->state >= PERF_EVENT_STATE_OFF)
12506 event->state = PERF_EVENT_STATE_INACTIVE;
12507 account_event_cpu(event, dst_cpu);
12508 perf_install_in_context(dst_ctx, event, dst_cpu);
12513 * Once all the siblings are setup properly, install the group leaders
12516 list_for_each_entry_safe(event, tmp, &events, migrate_entry) {
12517 list_del(&event->migrate_entry);
12518 if (event->state >= PERF_EVENT_STATE_OFF)
12519 event->state = PERF_EVENT_STATE_INACTIVE;
12520 account_event_cpu(event, dst_cpu);
12521 perf_install_in_context(dst_ctx, event, dst_cpu);
12524 mutex_unlock(&dst_ctx->mutex);
12525 mutex_unlock(&src_ctx->mutex);
12527 EXPORT_SYMBOL_GPL(perf_pmu_migrate_context);
12529 static void sync_child_event(struct perf_event *child_event)
12531 struct perf_event *parent_event = child_event->parent;
12534 if (child_event->attr.inherit_stat) {
12535 struct task_struct *task = child_event->ctx->task;
12537 if (task && task != TASK_TOMBSTONE)
12538 perf_event_read_event(child_event, task);
12541 child_val = perf_event_count(child_event);
12544 * Add back the child's count to the parent's count:
12546 atomic64_add(child_val, &parent_event->child_count);
12547 atomic64_add(child_event->total_time_enabled,
12548 &parent_event->child_total_time_enabled);
12549 atomic64_add(child_event->total_time_running,
12550 &parent_event->child_total_time_running);
12554 perf_event_exit_event(struct perf_event *event, struct perf_event_context *ctx)
12556 struct perf_event *parent_event = event->parent;
12557 unsigned long detach_flags = 0;
12559 if (parent_event) {
12561 * Do not destroy the 'original' grouping; because of the
12562 * context switch optimization the original events could've
12563 * ended up in a random child task.
12565 * If we were to destroy the original group, all group related
12566 * operations would cease to function properly after this
12567 * random child dies.
12569 * Do destroy all inherited groups, we don't care about those
12570 * and being thorough is better.
12572 detach_flags = DETACH_GROUP | DETACH_CHILD;
12573 mutex_lock(&parent_event->child_mutex);
12576 perf_remove_from_context(event, detach_flags);
12578 raw_spin_lock_irq(&ctx->lock);
12579 if (event->state > PERF_EVENT_STATE_EXIT)
12580 perf_event_set_state(event, PERF_EVENT_STATE_EXIT);
12581 raw_spin_unlock_irq(&ctx->lock);
12584 * Child events can be freed.
12586 if (parent_event) {
12587 mutex_unlock(&parent_event->child_mutex);
12589 * Kick perf_poll() for is_event_hup();
12591 perf_event_wakeup(parent_event);
12593 put_event(parent_event);
12598 * Parent events are governed by their filedesc, retain them.
12600 perf_event_wakeup(event);
12603 static void perf_event_exit_task_context(struct task_struct *child, int ctxn)
12605 struct perf_event_context *child_ctx, *clone_ctx = NULL;
12606 struct perf_event *child_event, *next;
12608 WARN_ON_ONCE(child != current);
12610 child_ctx = perf_pin_task_context(child, ctxn);
12615 * In order to reduce the amount of tricky in ctx tear-down, we hold
12616 * ctx::mutex over the entire thing. This serializes against almost
12617 * everything that wants to access the ctx.
12619 * The exception is sys_perf_event_open() /
12620 * perf_event_create_kernel_count() which does find_get_context()
12621 * without ctx::mutex (it cannot because of the move_group double mutex
12622 * lock thing). See the comments in perf_install_in_context().
12624 mutex_lock(&child_ctx->mutex);
12627 * In a single ctx::lock section, de-schedule the events and detach the
12628 * context from the task such that we cannot ever get it scheduled back
12631 raw_spin_lock_irq(&child_ctx->lock);
12632 task_ctx_sched_out(__get_cpu_context(child_ctx), child_ctx, EVENT_ALL);
12635 * Now that the context is inactive, destroy the task <-> ctx relation
12636 * and mark the context dead.
12638 RCU_INIT_POINTER(child->perf_event_ctxp[ctxn], NULL);
12639 put_ctx(child_ctx); /* cannot be last */
12640 WRITE_ONCE(child_ctx->task, TASK_TOMBSTONE);
12641 put_task_struct(current); /* cannot be last */
12643 clone_ctx = unclone_ctx(child_ctx);
12644 raw_spin_unlock_irq(&child_ctx->lock);
12647 put_ctx(clone_ctx);
12650 * Report the task dead after unscheduling the events so that we
12651 * won't get any samples after PERF_RECORD_EXIT. We can however still
12652 * get a few PERF_RECORD_READ events.
12654 perf_event_task(child, child_ctx, 0);
12656 list_for_each_entry_safe(child_event, next, &child_ctx->event_list, event_entry)
12657 perf_event_exit_event(child_event, child_ctx);
12659 mutex_unlock(&child_ctx->mutex);
12661 put_ctx(child_ctx);
12665 * When a child task exits, feed back event values to parent events.
12667 * Can be called with exec_update_lock held when called from
12668 * setup_new_exec().
12670 void perf_event_exit_task(struct task_struct *child)
12672 struct perf_event *event, *tmp;
12675 mutex_lock(&child->perf_event_mutex);
12676 list_for_each_entry_safe(event, tmp, &child->perf_event_list,
12678 list_del_init(&event->owner_entry);
12681 * Ensure the list deletion is visible before we clear
12682 * the owner, closes a race against perf_release() where
12683 * we need to serialize on the owner->perf_event_mutex.
12685 smp_store_release(&event->owner, NULL);
12687 mutex_unlock(&child->perf_event_mutex);
12689 for_each_task_context_nr(ctxn)
12690 perf_event_exit_task_context(child, ctxn);
12693 * The perf_event_exit_task_context calls perf_event_task
12694 * with child's task_ctx, which generates EXIT events for
12695 * child contexts and sets child->perf_event_ctxp[] to NULL.
12696 * At this point we need to send EXIT events to cpu contexts.
12698 perf_event_task(child, NULL, 0);
12701 static void perf_free_event(struct perf_event *event,
12702 struct perf_event_context *ctx)
12704 struct perf_event *parent = event->parent;
12706 if (WARN_ON_ONCE(!parent))
12709 mutex_lock(&parent->child_mutex);
12710 list_del_init(&event->child_list);
12711 mutex_unlock(&parent->child_mutex);
12715 raw_spin_lock_irq(&ctx->lock);
12716 perf_group_detach(event);
12717 list_del_event(event, ctx);
12718 raw_spin_unlock_irq(&ctx->lock);
12723 * Free a context as created by inheritance by perf_event_init_task() below,
12724 * used by fork() in case of fail.
12726 * Even though the task has never lived, the context and events have been
12727 * exposed through the child_list, so we must take care tearing it all down.
12729 void perf_event_free_task(struct task_struct *task)
12731 struct perf_event_context *ctx;
12732 struct perf_event *event, *tmp;
12735 for_each_task_context_nr(ctxn) {
12736 ctx = task->perf_event_ctxp[ctxn];
12740 mutex_lock(&ctx->mutex);
12741 raw_spin_lock_irq(&ctx->lock);
12743 * Destroy the task <-> ctx relation and mark the context dead.
12745 * This is important because even though the task hasn't been
12746 * exposed yet the context has been (through child_list).
12748 RCU_INIT_POINTER(task->perf_event_ctxp[ctxn], NULL);
12749 WRITE_ONCE(ctx->task, TASK_TOMBSTONE);
12750 put_task_struct(task); /* cannot be last */
12751 raw_spin_unlock_irq(&ctx->lock);
12753 list_for_each_entry_safe(event, tmp, &ctx->event_list, event_entry)
12754 perf_free_event(event, ctx);
12756 mutex_unlock(&ctx->mutex);
12759 * perf_event_release_kernel() could've stolen some of our
12760 * child events and still have them on its free_list. In that
12761 * case we must wait for these events to have been freed (in
12762 * particular all their references to this task must've been
12765 * Without this copy_process() will unconditionally free this
12766 * task (irrespective of its reference count) and
12767 * _free_event()'s put_task_struct(event->hw.target) will be a
12770 * Wait for all events to drop their context reference.
12772 wait_var_event(&ctx->refcount, refcount_read(&ctx->refcount) == 1);
12773 put_ctx(ctx); /* must be last */
12777 void perf_event_delayed_put(struct task_struct *task)
12781 for_each_task_context_nr(ctxn)
12782 WARN_ON_ONCE(task->perf_event_ctxp[ctxn]);
12785 struct file *perf_event_get(unsigned int fd)
12787 struct file *file = fget(fd);
12789 return ERR_PTR(-EBADF);
12791 if (file->f_op != &perf_fops) {
12793 return ERR_PTR(-EBADF);
12799 const struct perf_event *perf_get_event(struct file *file)
12801 if (file->f_op != &perf_fops)
12802 return ERR_PTR(-EINVAL);
12804 return file->private_data;
12807 const struct perf_event_attr *perf_event_attrs(struct perf_event *event)
12810 return ERR_PTR(-EINVAL);
12812 return &event->attr;
12816 * Inherit an event from parent task to child task.
12819 * - valid pointer on success
12820 * - NULL for orphaned events
12821 * - IS_ERR() on error
12823 static struct perf_event *
12824 inherit_event(struct perf_event *parent_event,
12825 struct task_struct *parent,
12826 struct perf_event_context *parent_ctx,
12827 struct task_struct *child,
12828 struct perf_event *group_leader,
12829 struct perf_event_context *child_ctx)
12831 enum perf_event_state parent_state = parent_event->state;
12832 struct perf_event *child_event;
12833 unsigned long flags;
12836 * Instead of creating recursive hierarchies of events,
12837 * we link inherited events back to the original parent,
12838 * which has a filp for sure, which we use as the reference
12841 if (parent_event->parent)
12842 parent_event = parent_event->parent;
12844 child_event = perf_event_alloc(&parent_event->attr,
12847 group_leader, parent_event,
12849 if (IS_ERR(child_event))
12850 return child_event;
12853 if ((child_event->attach_state & PERF_ATTACH_TASK_DATA) &&
12854 !child_ctx->task_ctx_data) {
12855 struct pmu *pmu = child_event->pmu;
12857 child_ctx->task_ctx_data = alloc_task_ctx_data(pmu);
12858 if (!child_ctx->task_ctx_data) {
12859 free_event(child_event);
12860 return ERR_PTR(-ENOMEM);
12865 * is_orphaned_event() and list_add_tail(&parent_event->child_list)
12866 * must be under the same lock in order to serialize against
12867 * perf_event_release_kernel(), such that either we must observe
12868 * is_orphaned_event() or they will observe us on the child_list.
12870 mutex_lock(&parent_event->child_mutex);
12871 if (is_orphaned_event(parent_event) ||
12872 !atomic_long_inc_not_zero(&parent_event->refcount)) {
12873 mutex_unlock(&parent_event->child_mutex);
12874 /* task_ctx_data is freed with child_ctx */
12875 free_event(child_event);
12879 get_ctx(child_ctx);
12882 * Make the child state follow the state of the parent event,
12883 * not its attr.disabled bit. We hold the parent's mutex,
12884 * so we won't race with perf_event_{en, dis}able_family.
12886 if (parent_state >= PERF_EVENT_STATE_INACTIVE)
12887 child_event->state = PERF_EVENT_STATE_INACTIVE;
12889 child_event->state = PERF_EVENT_STATE_OFF;
12891 if (parent_event->attr.freq) {
12892 u64 sample_period = parent_event->hw.sample_period;
12893 struct hw_perf_event *hwc = &child_event->hw;
12895 hwc->sample_period = sample_period;
12896 hwc->last_period = sample_period;
12898 local64_set(&hwc->period_left, sample_period);
12901 child_event->ctx = child_ctx;
12902 child_event->overflow_handler = parent_event->overflow_handler;
12903 child_event->overflow_handler_context
12904 = parent_event->overflow_handler_context;
12907 * Precalculate sample_data sizes
12909 perf_event__header_size(child_event);
12910 perf_event__id_header_size(child_event);
12913 * Link it up in the child's context:
12915 raw_spin_lock_irqsave(&child_ctx->lock, flags);
12916 add_event_to_ctx(child_event, child_ctx);
12917 child_event->attach_state |= PERF_ATTACH_CHILD;
12918 raw_spin_unlock_irqrestore(&child_ctx->lock, flags);
12921 * Link this into the parent event's child list
12923 list_add_tail(&child_event->child_list, &parent_event->child_list);
12924 mutex_unlock(&parent_event->child_mutex);
12926 return child_event;
12930 * Inherits an event group.
12932 * This will quietly suppress orphaned events; !inherit_event() is not an error.
12933 * This matches with perf_event_release_kernel() removing all child events.
12939 static int inherit_group(struct perf_event *parent_event,
12940 struct task_struct *parent,
12941 struct perf_event_context *parent_ctx,
12942 struct task_struct *child,
12943 struct perf_event_context *child_ctx)
12945 struct perf_event *leader;
12946 struct perf_event *sub;
12947 struct perf_event *child_ctr;
12949 leader = inherit_event(parent_event, parent, parent_ctx,
12950 child, NULL, child_ctx);
12951 if (IS_ERR(leader))
12952 return PTR_ERR(leader);
12954 * @leader can be NULL here because of is_orphaned_event(). In this
12955 * case inherit_event() will create individual events, similar to what
12956 * perf_group_detach() would do anyway.
12958 for_each_sibling_event(sub, parent_event) {
12959 child_ctr = inherit_event(sub, parent, parent_ctx,
12960 child, leader, child_ctx);
12961 if (IS_ERR(child_ctr))
12962 return PTR_ERR(child_ctr);
12964 if (sub->aux_event == parent_event && child_ctr &&
12965 !perf_get_aux_event(child_ctr, leader))
12972 * Creates the child task context and tries to inherit the event-group.
12974 * Clears @inherited_all on !attr.inherited or error. Note that we'll leave
12975 * inherited_all set when we 'fail' to inherit an orphaned event; this is
12976 * consistent with perf_event_release_kernel() removing all child events.
12983 inherit_task_group(struct perf_event *event, struct task_struct *parent,
12984 struct perf_event_context *parent_ctx,
12985 struct task_struct *child, int ctxn,
12986 u64 clone_flags, int *inherited_all)
12989 struct perf_event_context *child_ctx;
12991 if (!event->attr.inherit ||
12992 (event->attr.inherit_thread && !(clone_flags & CLONE_THREAD)) ||
12993 /* Do not inherit if sigtrap and signal handlers were cleared. */
12994 (event->attr.sigtrap && (clone_flags & CLONE_CLEAR_SIGHAND))) {
12995 *inherited_all = 0;
12999 child_ctx = child->perf_event_ctxp[ctxn];
13002 * This is executed from the parent task context, so
13003 * inherit events that have been marked for cloning.
13004 * First allocate and initialize a context for the
13007 child_ctx = alloc_perf_context(parent_ctx->pmu, child);
13011 child->perf_event_ctxp[ctxn] = child_ctx;
13014 ret = inherit_group(event, parent, parent_ctx,
13018 *inherited_all = 0;
13024 * Initialize the perf_event context in task_struct
13026 static int perf_event_init_context(struct task_struct *child, int ctxn,
13029 struct perf_event_context *child_ctx, *parent_ctx;
13030 struct perf_event_context *cloned_ctx;
13031 struct perf_event *event;
13032 struct task_struct *parent = current;
13033 int inherited_all = 1;
13034 unsigned long flags;
13037 if (likely(!parent->perf_event_ctxp[ctxn]))
13041 * If the parent's context is a clone, pin it so it won't get
13042 * swapped under us.
13044 parent_ctx = perf_pin_task_context(parent, ctxn);
13049 * No need to check if parent_ctx != NULL here; since we saw
13050 * it non-NULL earlier, the only reason for it to become NULL
13051 * is if we exit, and since we're currently in the middle of
13052 * a fork we can't be exiting at the same time.
13056 * Lock the parent list. No need to lock the child - not PID
13057 * hashed yet and not running, so nobody can access it.
13059 mutex_lock(&parent_ctx->mutex);
13062 * We dont have to disable NMIs - we are only looking at
13063 * the list, not manipulating it:
13065 perf_event_groups_for_each(event, &parent_ctx->pinned_groups) {
13066 ret = inherit_task_group(event, parent, parent_ctx,
13067 child, ctxn, clone_flags,
13074 * We can't hold ctx->lock when iterating the ->flexible_group list due
13075 * to allocations, but we need to prevent rotation because
13076 * rotate_ctx() will change the list from interrupt context.
13078 raw_spin_lock_irqsave(&parent_ctx->lock, flags);
13079 parent_ctx->rotate_disable = 1;
13080 raw_spin_unlock_irqrestore(&parent_ctx->lock, flags);
13082 perf_event_groups_for_each(event, &parent_ctx->flexible_groups) {
13083 ret = inherit_task_group(event, parent, parent_ctx,
13084 child, ctxn, clone_flags,
13090 raw_spin_lock_irqsave(&parent_ctx->lock, flags);
13091 parent_ctx->rotate_disable = 0;
13093 child_ctx = child->perf_event_ctxp[ctxn];
13095 if (child_ctx && inherited_all) {
13097 * Mark the child context as a clone of the parent
13098 * context, or of whatever the parent is a clone of.
13100 * Note that if the parent is a clone, the holding of
13101 * parent_ctx->lock avoids it from being uncloned.
13103 cloned_ctx = parent_ctx->parent_ctx;
13105 child_ctx->parent_ctx = cloned_ctx;
13106 child_ctx->parent_gen = parent_ctx->parent_gen;
13108 child_ctx->parent_ctx = parent_ctx;
13109 child_ctx->parent_gen = parent_ctx->generation;
13111 get_ctx(child_ctx->parent_ctx);
13114 raw_spin_unlock_irqrestore(&parent_ctx->lock, flags);
13116 mutex_unlock(&parent_ctx->mutex);
13118 perf_unpin_context(parent_ctx);
13119 put_ctx(parent_ctx);
13125 * Initialize the perf_event context in task_struct
13127 int perf_event_init_task(struct task_struct *child, u64 clone_flags)
13131 memset(child->perf_event_ctxp, 0, sizeof(child->perf_event_ctxp));
13132 mutex_init(&child->perf_event_mutex);
13133 INIT_LIST_HEAD(&child->perf_event_list);
13135 for_each_task_context_nr(ctxn) {
13136 ret = perf_event_init_context(child, ctxn, clone_flags);
13138 perf_event_free_task(child);
13146 static void __init perf_event_init_all_cpus(void)
13148 struct swevent_htable *swhash;
13151 zalloc_cpumask_var(&perf_online_mask, GFP_KERNEL);
13153 for_each_possible_cpu(cpu) {
13154 swhash = &per_cpu(swevent_htable, cpu);
13155 mutex_init(&swhash->hlist_mutex);
13156 INIT_LIST_HEAD(&per_cpu(active_ctx_list, cpu));
13158 INIT_LIST_HEAD(&per_cpu(pmu_sb_events.list, cpu));
13159 raw_spin_lock_init(&per_cpu(pmu_sb_events.lock, cpu));
13161 #ifdef CONFIG_CGROUP_PERF
13162 INIT_LIST_HEAD(&per_cpu(cgrp_cpuctx_list, cpu));
13164 INIT_LIST_HEAD(&per_cpu(sched_cb_list, cpu));
13168 static void perf_swevent_init_cpu(unsigned int cpu)
13170 struct swevent_htable *swhash = &per_cpu(swevent_htable, cpu);
13172 mutex_lock(&swhash->hlist_mutex);
13173 if (swhash->hlist_refcount > 0 && !swevent_hlist_deref(swhash)) {
13174 struct swevent_hlist *hlist;
13176 hlist = kzalloc_node(sizeof(*hlist), GFP_KERNEL, cpu_to_node(cpu));
13178 rcu_assign_pointer(swhash->swevent_hlist, hlist);
13180 mutex_unlock(&swhash->hlist_mutex);
13183 #if defined CONFIG_HOTPLUG_CPU || defined CONFIG_KEXEC_CORE
13184 static void __perf_event_exit_context(void *__info)
13186 struct perf_event_context *ctx = __info;
13187 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
13188 struct perf_event *event;
13190 raw_spin_lock(&ctx->lock);
13191 ctx_sched_out(ctx, cpuctx, EVENT_TIME);
13192 list_for_each_entry(event, &ctx->event_list, event_entry)
13193 __perf_remove_from_context(event, cpuctx, ctx, (void *)DETACH_GROUP);
13194 raw_spin_unlock(&ctx->lock);
13197 static void perf_event_exit_cpu_context(int cpu)
13199 struct perf_cpu_context *cpuctx;
13200 struct perf_event_context *ctx;
13203 mutex_lock(&pmus_lock);
13204 list_for_each_entry(pmu, &pmus, entry) {
13205 cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
13206 ctx = &cpuctx->ctx;
13208 mutex_lock(&ctx->mutex);
13209 smp_call_function_single(cpu, __perf_event_exit_context, ctx, 1);
13210 cpuctx->online = 0;
13211 mutex_unlock(&ctx->mutex);
13213 cpumask_clear_cpu(cpu, perf_online_mask);
13214 mutex_unlock(&pmus_lock);
13218 static void perf_event_exit_cpu_context(int cpu) { }
13222 int perf_event_init_cpu(unsigned int cpu)
13224 struct perf_cpu_context *cpuctx;
13225 struct perf_event_context *ctx;
13228 perf_swevent_init_cpu(cpu);
13230 mutex_lock(&pmus_lock);
13231 cpumask_set_cpu(cpu, perf_online_mask);
13232 list_for_each_entry(pmu, &pmus, entry) {
13233 cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
13234 ctx = &cpuctx->ctx;
13236 mutex_lock(&ctx->mutex);
13237 cpuctx->online = 1;
13238 mutex_unlock(&ctx->mutex);
13240 mutex_unlock(&pmus_lock);
13245 int perf_event_exit_cpu(unsigned int cpu)
13247 perf_event_exit_cpu_context(cpu);
13252 perf_reboot(struct notifier_block *notifier, unsigned long val, void *v)
13256 for_each_online_cpu(cpu)
13257 perf_event_exit_cpu(cpu);
13263 * Run the perf reboot notifier at the very last possible moment so that
13264 * the generic watchdog code runs as long as possible.
13266 static struct notifier_block perf_reboot_notifier = {
13267 .notifier_call = perf_reboot,
13268 .priority = INT_MIN,
13271 void __init perf_event_init(void)
13275 idr_init(&pmu_idr);
13277 perf_event_init_all_cpus();
13278 init_srcu_struct(&pmus_srcu);
13279 perf_pmu_register(&perf_swevent, "software", PERF_TYPE_SOFTWARE);
13280 perf_pmu_register(&perf_cpu_clock, NULL, -1);
13281 perf_pmu_register(&perf_task_clock, NULL, -1);
13282 perf_tp_register();
13283 perf_event_init_cpu(smp_processor_id());
13284 register_reboot_notifier(&perf_reboot_notifier);
13286 ret = init_hw_breakpoint();
13287 WARN(ret, "hw_breakpoint initialization failed with: %d", ret);
13289 perf_event_cache = KMEM_CACHE(perf_event, SLAB_PANIC);
13292 * Build time assertion that we keep the data_head at the intended
13293 * location. IOW, validation we got the __reserved[] size right.
13295 BUILD_BUG_ON((offsetof(struct perf_event_mmap_page, data_head))
13299 ssize_t perf_event_sysfs_show(struct device *dev, struct device_attribute *attr,
13302 struct perf_pmu_events_attr *pmu_attr =
13303 container_of(attr, struct perf_pmu_events_attr, attr);
13305 if (pmu_attr->event_str)
13306 return sprintf(page, "%s\n", pmu_attr->event_str);
13310 EXPORT_SYMBOL_GPL(perf_event_sysfs_show);
13312 static int __init perf_event_sysfs_init(void)
13317 mutex_lock(&pmus_lock);
13319 ret = bus_register(&pmu_bus);
13323 list_for_each_entry(pmu, &pmus, entry) {
13324 if (!pmu->name || pmu->type < 0)
13327 ret = pmu_dev_alloc(pmu);
13328 WARN(ret, "Failed to register pmu: %s, reason %d\n", pmu->name, ret);
13330 pmu_bus_running = 1;
13334 mutex_unlock(&pmus_lock);
13338 device_initcall(perf_event_sysfs_init);
13340 #ifdef CONFIG_CGROUP_PERF
13341 static struct cgroup_subsys_state *
13342 perf_cgroup_css_alloc(struct cgroup_subsys_state *parent_css)
13344 struct perf_cgroup *jc;
13346 jc = kzalloc(sizeof(*jc), GFP_KERNEL);
13348 return ERR_PTR(-ENOMEM);
13350 jc->info = alloc_percpu(struct perf_cgroup_info);
13353 return ERR_PTR(-ENOMEM);
13359 static void perf_cgroup_css_free(struct cgroup_subsys_state *css)
13361 struct perf_cgroup *jc = container_of(css, struct perf_cgroup, css);
13363 free_percpu(jc->info);
13367 static int perf_cgroup_css_online(struct cgroup_subsys_state *css)
13369 perf_event_cgroup(css->cgroup);
13373 static int __perf_cgroup_move(void *info)
13375 struct task_struct *task = info;
13377 perf_cgroup_switch(task, PERF_CGROUP_SWOUT | PERF_CGROUP_SWIN);
13382 static void perf_cgroup_attach(struct cgroup_taskset *tset)
13384 struct task_struct *task;
13385 struct cgroup_subsys_state *css;
13387 cgroup_taskset_for_each(task, css, tset)
13388 task_function_call(task, __perf_cgroup_move, task);
13391 struct cgroup_subsys perf_event_cgrp_subsys = {
13392 .css_alloc = perf_cgroup_css_alloc,
13393 .css_free = perf_cgroup_css_free,
13394 .css_online = perf_cgroup_css_online,
13395 .attach = perf_cgroup_attach,
13397 * Implicitly enable on dfl hierarchy so that perf events can
13398 * always be filtered by cgroup2 path as long as perf_event
13399 * controller is not mounted on a legacy hierarchy.
13401 .implicit_on_dfl = true,
13404 #endif /* CONFIG_CGROUP_PERF */