1 // SPDX-License-Identifier: GPL-2.0
3 * Performance events core code:
5 * Copyright (C) 2008 Thomas Gleixner <tglx@linutronix.de>
6 * Copyright (C) 2008-2011 Red Hat, Inc., Ingo Molnar
7 * Copyright (C) 2008-2011 Red Hat, Inc., Peter Zijlstra
8 * Copyright © 2009 Paul Mackerras, IBM Corp. <paulus@au1.ibm.com>
13 #include <linux/cpu.h>
14 #include <linux/smp.h>
15 #include <linux/idr.h>
16 #include <linux/file.h>
17 #include <linux/poll.h>
18 #include <linux/slab.h>
19 #include <linux/hash.h>
20 #include <linux/tick.h>
21 #include <linux/sysfs.h>
22 #include <linux/dcache.h>
23 #include <linux/percpu.h>
24 #include <linux/ptrace.h>
25 #include <linux/reboot.h>
26 #include <linux/vmstat.h>
27 #include <linux/device.h>
28 #include <linux/export.h>
29 #include <linux/vmalloc.h>
30 #include <linux/hardirq.h>
31 #include <linux/hugetlb.h>
32 #include <linux/rculist.h>
33 #include <linux/uaccess.h>
34 #include <linux/syscalls.h>
35 #include <linux/anon_inodes.h>
36 #include <linux/kernel_stat.h>
37 #include <linux/cgroup.h>
38 #include <linux/perf_event.h>
39 #include <linux/trace_events.h>
40 #include <linux/hw_breakpoint.h>
41 #include <linux/mm_types.h>
42 #include <linux/module.h>
43 #include <linux/mman.h>
44 #include <linux/compat.h>
45 #include <linux/bpf.h>
46 #include <linux/filter.h>
47 #include <linux/namei.h>
48 #include <linux/parser.h>
49 #include <linux/sched/clock.h>
50 #include <linux/sched/mm.h>
51 #include <linux/proc_ns.h>
52 #include <linux/mount.h>
53 #include <linux/min_heap.h>
54 #include <linux/highmem.h>
55 #include <linux/pgtable.h>
56 #include <linux/buildid.h>
60 #include <asm/irq_regs.h>
62 typedef int (*remote_function_f)(void *);
64 struct remote_function_call {
65 struct task_struct *p;
66 remote_function_f func;
71 static void remote_function(void *data)
73 struct remote_function_call *tfc = data;
74 struct task_struct *p = tfc->p;
78 if (task_cpu(p) != smp_processor_id())
82 * Now that we're on right CPU with IRQs disabled, we can test
83 * if we hit the right task without races.
86 tfc->ret = -ESRCH; /* No such (running) process */
91 tfc->ret = tfc->func(tfc->info);
95 * task_function_call - call a function on the cpu on which a task runs
96 * @p: the task to evaluate
97 * @func: the function to be called
98 * @info: the function call argument
100 * Calls the function @func when the task is currently running. This might
101 * be on the current CPU, which just calls the function directly. This will
102 * retry due to any failures in smp_call_function_single(), such as if the
103 * task_cpu() goes offline concurrently.
105 * returns @func return value or -ESRCH or -ENXIO when the process isn't running
108 task_function_call(struct task_struct *p, remote_function_f func, void *info)
110 struct remote_function_call data = {
119 ret = smp_call_function_single(task_cpu(p), remote_function,
134 * cpu_function_call - call a function on the cpu
135 * @cpu: target cpu to queue this function
136 * @func: the function to be called
137 * @info: the function call argument
139 * Calls the function @func on the remote cpu.
141 * returns: @func return value or -ENXIO when the cpu is offline
143 static int cpu_function_call(int cpu, remote_function_f func, void *info)
145 struct remote_function_call data = {
149 .ret = -ENXIO, /* No such CPU */
152 smp_call_function_single(cpu, remote_function, &data, 1);
157 static inline struct perf_cpu_context *
158 __get_cpu_context(struct perf_event_context *ctx)
160 return this_cpu_ptr(ctx->pmu->pmu_cpu_context);
163 static void perf_ctx_lock(struct perf_cpu_context *cpuctx,
164 struct perf_event_context *ctx)
166 raw_spin_lock(&cpuctx->ctx.lock);
168 raw_spin_lock(&ctx->lock);
171 static void perf_ctx_unlock(struct perf_cpu_context *cpuctx,
172 struct perf_event_context *ctx)
175 raw_spin_unlock(&ctx->lock);
176 raw_spin_unlock(&cpuctx->ctx.lock);
179 #define TASK_TOMBSTONE ((void *)-1L)
181 static bool is_kernel_event(struct perf_event *event)
183 return READ_ONCE(event->owner) == TASK_TOMBSTONE;
187 * On task ctx scheduling...
189 * When !ctx->nr_events a task context will not be scheduled. This means
190 * we can disable the scheduler hooks (for performance) without leaving
191 * pending task ctx state.
193 * This however results in two special cases:
195 * - removing the last event from a task ctx; this is relatively straight
196 * forward and is done in __perf_remove_from_context.
198 * - adding the first event to a task ctx; this is tricky because we cannot
199 * rely on ctx->is_active and therefore cannot use event_function_call().
200 * See perf_install_in_context().
202 * If ctx->nr_events, then ctx->is_active and cpuctx->task_ctx are set.
205 typedef void (*event_f)(struct perf_event *, struct perf_cpu_context *,
206 struct perf_event_context *, void *);
208 struct event_function_struct {
209 struct perf_event *event;
214 static int event_function(void *info)
216 struct event_function_struct *efs = info;
217 struct perf_event *event = efs->event;
218 struct perf_event_context *ctx = event->ctx;
219 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
220 struct perf_event_context *task_ctx = cpuctx->task_ctx;
223 lockdep_assert_irqs_disabled();
225 perf_ctx_lock(cpuctx, task_ctx);
227 * Since we do the IPI call without holding ctx->lock things can have
228 * changed, double check we hit the task we set out to hit.
231 if (ctx->task != current) {
237 * We only use event_function_call() on established contexts,
238 * and event_function() is only ever called when active (or
239 * rather, we'll have bailed in task_function_call() or the
240 * above ctx->task != current test), therefore we must have
241 * ctx->is_active here.
243 WARN_ON_ONCE(!ctx->is_active);
245 * And since we have ctx->is_active, cpuctx->task_ctx must
248 WARN_ON_ONCE(task_ctx != ctx);
250 WARN_ON_ONCE(&cpuctx->ctx != ctx);
253 efs->func(event, cpuctx, ctx, efs->data);
255 perf_ctx_unlock(cpuctx, task_ctx);
260 static void event_function_call(struct perf_event *event, event_f func, void *data)
262 struct perf_event_context *ctx = event->ctx;
263 struct task_struct *task = READ_ONCE(ctx->task); /* verified in event_function */
264 struct event_function_struct efs = {
270 if (!event->parent) {
272 * If this is a !child event, we must hold ctx::mutex to
273 * stabilize the event->ctx relation. See
274 * perf_event_ctx_lock().
276 lockdep_assert_held(&ctx->mutex);
280 cpu_function_call(event->cpu, event_function, &efs);
284 if (task == TASK_TOMBSTONE)
288 if (!task_function_call(task, event_function, &efs))
291 raw_spin_lock_irq(&ctx->lock);
293 * Reload the task pointer, it might have been changed by
294 * a concurrent perf_event_context_sched_out().
297 if (task == TASK_TOMBSTONE) {
298 raw_spin_unlock_irq(&ctx->lock);
301 if (ctx->is_active) {
302 raw_spin_unlock_irq(&ctx->lock);
305 func(event, NULL, ctx, data);
306 raw_spin_unlock_irq(&ctx->lock);
310 * Similar to event_function_call() + event_function(), but hard assumes IRQs
311 * are already disabled and we're on the right CPU.
313 static void event_function_local(struct perf_event *event, event_f func, void *data)
315 struct perf_event_context *ctx = event->ctx;
316 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
317 struct task_struct *task = READ_ONCE(ctx->task);
318 struct perf_event_context *task_ctx = NULL;
320 lockdep_assert_irqs_disabled();
323 if (task == TASK_TOMBSTONE)
329 perf_ctx_lock(cpuctx, task_ctx);
332 if (task == TASK_TOMBSTONE)
337 * We must be either inactive or active and the right task,
338 * otherwise we're screwed, since we cannot IPI to somewhere
341 if (ctx->is_active) {
342 if (WARN_ON_ONCE(task != current))
345 if (WARN_ON_ONCE(cpuctx->task_ctx != ctx))
349 WARN_ON_ONCE(&cpuctx->ctx != ctx);
352 func(event, cpuctx, ctx, data);
354 perf_ctx_unlock(cpuctx, task_ctx);
357 #define PERF_FLAG_ALL (PERF_FLAG_FD_NO_GROUP |\
358 PERF_FLAG_FD_OUTPUT |\
359 PERF_FLAG_PID_CGROUP |\
360 PERF_FLAG_FD_CLOEXEC)
363 * branch priv levels that need permission checks
365 #define PERF_SAMPLE_BRANCH_PERM_PLM \
366 (PERF_SAMPLE_BRANCH_KERNEL |\
367 PERF_SAMPLE_BRANCH_HV)
370 EVENT_FLEXIBLE = 0x1,
373 /* see ctx_resched() for details */
375 EVENT_ALL = EVENT_FLEXIBLE | EVENT_PINNED,
379 * perf_sched_events : >0 events exist
380 * perf_cgroup_events: >0 per-cpu cgroup events exist on this cpu
383 static void perf_sched_delayed(struct work_struct *work);
384 DEFINE_STATIC_KEY_FALSE(perf_sched_events);
385 static DECLARE_DELAYED_WORK(perf_sched_work, perf_sched_delayed);
386 static DEFINE_MUTEX(perf_sched_mutex);
387 static atomic_t perf_sched_count;
389 static DEFINE_PER_CPU(atomic_t, perf_cgroup_events);
390 static DEFINE_PER_CPU(int, perf_sched_cb_usages);
391 static DEFINE_PER_CPU(struct pmu_event_list, pmu_sb_events);
393 static atomic_t nr_mmap_events __read_mostly;
394 static atomic_t nr_comm_events __read_mostly;
395 static atomic_t nr_namespaces_events __read_mostly;
396 static atomic_t nr_task_events __read_mostly;
397 static atomic_t nr_freq_events __read_mostly;
398 static atomic_t nr_switch_events __read_mostly;
399 static atomic_t nr_ksymbol_events __read_mostly;
400 static atomic_t nr_bpf_events __read_mostly;
401 static atomic_t nr_cgroup_events __read_mostly;
402 static atomic_t nr_text_poke_events __read_mostly;
403 static atomic_t nr_build_id_events __read_mostly;
405 static LIST_HEAD(pmus);
406 static DEFINE_MUTEX(pmus_lock);
407 static struct srcu_struct pmus_srcu;
408 static cpumask_var_t perf_online_mask;
409 static struct kmem_cache *perf_event_cache;
412 * perf event paranoia level:
413 * -1 - not paranoid at all
414 * 0 - disallow raw tracepoint access for unpriv
415 * 1 - disallow cpu events for unpriv
416 * 2 - disallow kernel profiling for unpriv
418 int sysctl_perf_event_paranoid __read_mostly = 2;
420 /* Minimum for 512 kiB + 1 user control page */
421 int sysctl_perf_event_mlock __read_mostly = 512 + (PAGE_SIZE / 1024); /* 'free' kiB per user */
424 * max perf event sample rate
426 #define DEFAULT_MAX_SAMPLE_RATE 100000
427 #define DEFAULT_SAMPLE_PERIOD_NS (NSEC_PER_SEC / DEFAULT_MAX_SAMPLE_RATE)
428 #define DEFAULT_CPU_TIME_MAX_PERCENT 25
430 int sysctl_perf_event_sample_rate __read_mostly = DEFAULT_MAX_SAMPLE_RATE;
432 static int max_samples_per_tick __read_mostly = DIV_ROUND_UP(DEFAULT_MAX_SAMPLE_RATE, HZ);
433 static int perf_sample_period_ns __read_mostly = DEFAULT_SAMPLE_PERIOD_NS;
435 static int perf_sample_allowed_ns __read_mostly =
436 DEFAULT_SAMPLE_PERIOD_NS * DEFAULT_CPU_TIME_MAX_PERCENT / 100;
438 static void update_perf_cpu_limits(void)
440 u64 tmp = perf_sample_period_ns;
442 tmp *= sysctl_perf_cpu_time_max_percent;
443 tmp = div_u64(tmp, 100);
447 WRITE_ONCE(perf_sample_allowed_ns, tmp);
450 static bool perf_rotate_context(struct perf_cpu_context *cpuctx);
452 int perf_proc_update_handler(struct ctl_table *table, int write,
453 void *buffer, size_t *lenp, loff_t *ppos)
456 int perf_cpu = sysctl_perf_cpu_time_max_percent;
458 * If throttling is disabled don't allow the write:
460 if (write && (perf_cpu == 100 || perf_cpu == 0))
463 ret = proc_dointvec_minmax(table, write, buffer, lenp, ppos);
467 max_samples_per_tick = DIV_ROUND_UP(sysctl_perf_event_sample_rate, HZ);
468 perf_sample_period_ns = NSEC_PER_SEC / sysctl_perf_event_sample_rate;
469 update_perf_cpu_limits();
474 int sysctl_perf_cpu_time_max_percent __read_mostly = DEFAULT_CPU_TIME_MAX_PERCENT;
476 int perf_cpu_time_max_percent_handler(struct ctl_table *table, int write,
477 void *buffer, size_t *lenp, loff_t *ppos)
479 int ret = proc_dointvec_minmax(table, write, buffer, lenp, ppos);
484 if (sysctl_perf_cpu_time_max_percent == 100 ||
485 sysctl_perf_cpu_time_max_percent == 0) {
487 "perf: Dynamic interrupt throttling disabled, can hang your system!\n");
488 WRITE_ONCE(perf_sample_allowed_ns, 0);
490 update_perf_cpu_limits();
497 * perf samples are done in some very critical code paths (NMIs).
498 * If they take too much CPU time, the system can lock up and not
499 * get any real work done. This will drop the sample rate when
500 * we detect that events are taking too long.
502 #define NR_ACCUMULATED_SAMPLES 128
503 static DEFINE_PER_CPU(u64, running_sample_length);
505 static u64 __report_avg;
506 static u64 __report_allowed;
508 static void perf_duration_warn(struct irq_work *w)
510 printk_ratelimited(KERN_INFO
511 "perf: interrupt took too long (%lld > %lld), lowering "
512 "kernel.perf_event_max_sample_rate to %d\n",
513 __report_avg, __report_allowed,
514 sysctl_perf_event_sample_rate);
517 static DEFINE_IRQ_WORK(perf_duration_work, perf_duration_warn);
519 void perf_sample_event_took(u64 sample_len_ns)
521 u64 max_len = READ_ONCE(perf_sample_allowed_ns);
529 /* Decay the counter by 1 average sample. */
530 running_len = __this_cpu_read(running_sample_length);
531 running_len -= running_len/NR_ACCUMULATED_SAMPLES;
532 running_len += sample_len_ns;
533 __this_cpu_write(running_sample_length, running_len);
536 * Note: this will be biased artifically low until we have
537 * seen NR_ACCUMULATED_SAMPLES. Doing it this way keeps us
538 * from having to maintain a count.
540 avg_len = running_len/NR_ACCUMULATED_SAMPLES;
541 if (avg_len <= max_len)
544 __report_avg = avg_len;
545 __report_allowed = max_len;
548 * Compute a throttle threshold 25% below the current duration.
550 avg_len += avg_len / 4;
551 max = (TICK_NSEC / 100) * sysctl_perf_cpu_time_max_percent;
557 WRITE_ONCE(perf_sample_allowed_ns, avg_len);
558 WRITE_ONCE(max_samples_per_tick, max);
560 sysctl_perf_event_sample_rate = max * HZ;
561 perf_sample_period_ns = NSEC_PER_SEC / sysctl_perf_event_sample_rate;
563 if (!irq_work_queue(&perf_duration_work)) {
564 early_printk("perf: interrupt took too long (%lld > %lld), lowering "
565 "kernel.perf_event_max_sample_rate to %d\n",
566 __report_avg, __report_allowed,
567 sysctl_perf_event_sample_rate);
571 static atomic64_t perf_event_id;
573 static void cpu_ctx_sched_out(struct perf_cpu_context *cpuctx,
574 enum event_type_t event_type);
576 static void cpu_ctx_sched_in(struct perf_cpu_context *cpuctx,
577 enum event_type_t event_type);
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);
677 * UP store-release, load-acquire
680 #define __store_release(ptr, val) \
683 WRITE_ONCE(*(ptr), (val)); \
686 #define __load_acquire(ptr) \
688 __unqual_scalar_typeof(*(ptr)) ___p = READ_ONCE(*(ptr)); \
693 #ifdef CONFIG_CGROUP_PERF
696 perf_cgroup_match(struct perf_event *event)
698 struct perf_event_context *ctx = event->ctx;
699 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
701 /* @event doesn't care about cgroup */
705 /* wants specific cgroup scope but @cpuctx isn't associated with any */
710 * Cgroup scoping is recursive. An event enabled for a cgroup is
711 * also enabled for all its descendant cgroups. If @cpuctx's
712 * cgroup is a descendant of @event's (the test covers identity
713 * case), it's a match.
715 return cgroup_is_descendant(cpuctx->cgrp->css.cgroup,
716 event->cgrp->css.cgroup);
719 static inline void perf_detach_cgroup(struct perf_event *event)
721 css_put(&event->cgrp->css);
725 static inline int is_cgroup_event(struct perf_event *event)
727 return event->cgrp != NULL;
730 static inline u64 perf_cgroup_event_time(struct perf_event *event)
732 struct perf_cgroup_info *t;
734 t = per_cpu_ptr(event->cgrp->info, event->cpu);
738 static inline u64 perf_cgroup_event_time_now(struct perf_event *event, u64 now)
740 struct perf_cgroup_info *t;
742 t = per_cpu_ptr(event->cgrp->info, event->cpu);
743 if (!__load_acquire(&t->active))
745 now += READ_ONCE(t->timeoffset);
749 static inline void __update_cgrp_time(struct perf_cgroup_info *info, u64 now, bool adv)
752 info->time += now - info->timestamp;
753 info->timestamp = now;
755 * see update_context_time()
757 WRITE_ONCE(info->timeoffset, info->time - info->timestamp);
760 static inline void update_cgrp_time_from_cpuctx(struct perf_cpu_context *cpuctx, bool final)
762 struct perf_cgroup *cgrp = cpuctx->cgrp;
763 struct cgroup_subsys_state *css;
764 struct perf_cgroup_info *info;
767 u64 now = perf_clock();
769 for (css = &cgrp->css; css; css = css->parent) {
770 cgrp = container_of(css, struct perf_cgroup, css);
771 info = this_cpu_ptr(cgrp->info);
773 __update_cgrp_time(info, now, true);
775 __store_release(&info->active, 0);
780 static inline void update_cgrp_time_from_event(struct perf_event *event)
782 struct perf_cgroup_info *info;
785 * ensure we access cgroup data only when needed and
786 * when we know the cgroup is pinned (css_get)
788 if (!is_cgroup_event(event))
791 info = this_cpu_ptr(event->cgrp->info);
793 * Do not update time when cgroup is not active
796 __update_cgrp_time(info, perf_clock(), true);
800 perf_cgroup_set_timestamp(struct perf_cpu_context *cpuctx)
802 struct perf_event_context *ctx = &cpuctx->ctx;
803 struct perf_cgroup *cgrp = cpuctx->cgrp;
804 struct perf_cgroup_info *info;
805 struct cgroup_subsys_state *css;
808 * ctx->lock held by caller
809 * ensure we do not access cgroup data
810 * unless we have the cgroup pinned (css_get)
815 WARN_ON_ONCE(!ctx->nr_cgroups);
817 for (css = &cgrp->css; css; css = css->parent) {
818 cgrp = container_of(css, struct perf_cgroup, css);
819 info = this_cpu_ptr(cgrp->info);
820 __update_cgrp_time(info, ctx->timestamp, false);
821 __store_release(&info->active, 1);
825 static DEFINE_PER_CPU(struct list_head, cgrp_cpuctx_list);
828 * reschedule events based on the cgroup constraint of task.
830 static void perf_cgroup_switch(struct task_struct *task)
832 struct perf_cgroup *cgrp;
833 struct perf_cpu_context *cpuctx, *tmp;
834 struct list_head *list;
838 * Disable interrupts and preemption to avoid this CPU's
839 * cgrp_cpuctx_entry to change under us.
841 local_irq_save(flags);
843 cgrp = perf_cgroup_from_task(task, NULL);
845 list = this_cpu_ptr(&cgrp_cpuctx_list);
846 list_for_each_entry_safe(cpuctx, tmp, list, cgrp_cpuctx_entry) {
847 WARN_ON_ONCE(cpuctx->ctx.nr_cgroups == 0);
848 if (READ_ONCE(cpuctx->cgrp) == cgrp)
851 perf_ctx_lock(cpuctx, cpuctx->task_ctx);
852 perf_pmu_disable(cpuctx->ctx.pmu);
854 cpu_ctx_sched_out(cpuctx, EVENT_ALL);
856 * must not be done before ctxswout due
857 * to update_cgrp_time_from_cpuctx() in
862 * set cgrp before ctxsw in to allow
863 * perf_cgroup_set_timestamp() in ctx_sched_in()
864 * to not have to pass task around
866 cpu_ctx_sched_in(cpuctx, EVENT_ALL);
868 perf_pmu_enable(cpuctx->ctx.pmu);
869 perf_ctx_unlock(cpuctx, cpuctx->task_ctx);
872 local_irq_restore(flags);
875 static int perf_cgroup_ensure_storage(struct perf_event *event,
876 struct cgroup_subsys_state *css)
878 struct perf_cpu_context *cpuctx;
879 struct perf_event **storage;
880 int cpu, heap_size, ret = 0;
883 * Allow storage to have sufficent space for an iterator for each
884 * possibly nested cgroup plus an iterator for events with no cgroup.
886 for (heap_size = 1; css; css = css->parent)
889 for_each_possible_cpu(cpu) {
890 cpuctx = per_cpu_ptr(event->pmu->pmu_cpu_context, cpu);
891 if (heap_size <= cpuctx->heap_size)
894 storage = kmalloc_node(heap_size * sizeof(struct perf_event *),
895 GFP_KERNEL, cpu_to_node(cpu));
901 raw_spin_lock_irq(&cpuctx->ctx.lock);
902 if (cpuctx->heap_size < heap_size) {
903 swap(cpuctx->heap, storage);
904 if (storage == cpuctx->heap_default)
906 cpuctx->heap_size = heap_size;
908 raw_spin_unlock_irq(&cpuctx->ctx.lock);
916 static inline int perf_cgroup_connect(int fd, struct perf_event *event,
917 struct perf_event_attr *attr,
918 struct perf_event *group_leader)
920 struct perf_cgroup *cgrp;
921 struct cgroup_subsys_state *css;
922 struct fd f = fdget(fd);
928 css = css_tryget_online_from_dir(f.file->f_path.dentry,
929 &perf_event_cgrp_subsys);
935 ret = perf_cgroup_ensure_storage(event, css);
939 cgrp = container_of(css, struct perf_cgroup, css);
943 * all events in a group must monitor
944 * the same cgroup because a task belongs
945 * to only one perf cgroup at a time
947 if (group_leader && group_leader->cgrp != cgrp) {
948 perf_detach_cgroup(event);
957 perf_cgroup_event_enable(struct perf_event *event, struct perf_event_context *ctx)
959 struct perf_cpu_context *cpuctx;
961 if (!is_cgroup_event(event))
965 * Because cgroup events are always per-cpu events,
966 * @ctx == &cpuctx->ctx.
968 cpuctx = container_of(ctx, struct perf_cpu_context, ctx);
970 if (ctx->nr_cgroups++)
973 cpuctx->cgrp = perf_cgroup_from_task(current, ctx);
974 list_add(&cpuctx->cgrp_cpuctx_entry,
975 per_cpu_ptr(&cgrp_cpuctx_list, event->cpu));
979 perf_cgroup_event_disable(struct perf_event *event, struct perf_event_context *ctx)
981 struct perf_cpu_context *cpuctx;
983 if (!is_cgroup_event(event))
987 * Because cgroup events are always per-cpu events,
988 * @ctx == &cpuctx->ctx.
990 cpuctx = container_of(ctx, struct perf_cpu_context, ctx);
992 if (--ctx->nr_cgroups)
996 list_del(&cpuctx->cgrp_cpuctx_entry);
999 #else /* !CONFIG_CGROUP_PERF */
1002 perf_cgroup_match(struct perf_event *event)
1007 static inline void perf_detach_cgroup(struct perf_event *event)
1010 static inline int is_cgroup_event(struct perf_event *event)
1015 static inline void update_cgrp_time_from_event(struct perf_event *event)
1019 static inline void update_cgrp_time_from_cpuctx(struct perf_cpu_context *cpuctx,
1024 static inline int perf_cgroup_connect(pid_t pid, struct perf_event *event,
1025 struct perf_event_attr *attr,
1026 struct perf_event *group_leader)
1032 perf_cgroup_set_timestamp(struct perf_cpu_context *cpuctx)
1036 static inline u64 perf_cgroup_event_time(struct perf_event *event)
1041 static inline u64 perf_cgroup_event_time_now(struct perf_event *event, u64 now)
1047 perf_cgroup_event_enable(struct perf_event *event, struct perf_event_context *ctx)
1052 perf_cgroup_event_disable(struct perf_event *event, struct perf_event_context *ctx)
1056 static void perf_cgroup_switch(struct task_struct *task)
1062 * set default to be dependent on timer tick just
1063 * like original code
1065 #define PERF_CPU_HRTIMER (1000 / HZ)
1067 * function must be called with interrupts disabled
1069 static enum hrtimer_restart perf_mux_hrtimer_handler(struct hrtimer *hr)
1071 struct perf_cpu_context *cpuctx;
1074 lockdep_assert_irqs_disabled();
1076 cpuctx = container_of(hr, struct perf_cpu_context, hrtimer);
1077 rotations = perf_rotate_context(cpuctx);
1079 raw_spin_lock(&cpuctx->hrtimer_lock);
1081 hrtimer_forward_now(hr, cpuctx->hrtimer_interval);
1083 cpuctx->hrtimer_active = 0;
1084 raw_spin_unlock(&cpuctx->hrtimer_lock);
1086 return rotations ? HRTIMER_RESTART : HRTIMER_NORESTART;
1089 static void __perf_mux_hrtimer_init(struct perf_cpu_context *cpuctx, int cpu)
1091 struct hrtimer *timer = &cpuctx->hrtimer;
1092 struct pmu *pmu = cpuctx->ctx.pmu;
1095 /* no multiplexing needed for SW PMU */
1096 if (pmu->task_ctx_nr == perf_sw_context)
1100 * check default is sane, if not set then force to
1101 * default interval (1/tick)
1103 interval = pmu->hrtimer_interval_ms;
1105 interval = pmu->hrtimer_interval_ms = PERF_CPU_HRTIMER;
1107 cpuctx->hrtimer_interval = ns_to_ktime(NSEC_PER_MSEC * interval);
1109 raw_spin_lock_init(&cpuctx->hrtimer_lock);
1110 hrtimer_init(timer, CLOCK_MONOTONIC, HRTIMER_MODE_ABS_PINNED_HARD);
1111 timer->function = perf_mux_hrtimer_handler;
1114 static int perf_mux_hrtimer_restart(struct perf_cpu_context *cpuctx)
1116 struct hrtimer *timer = &cpuctx->hrtimer;
1117 struct pmu *pmu = cpuctx->ctx.pmu;
1118 unsigned long flags;
1120 /* not for SW PMU */
1121 if (pmu->task_ctx_nr == perf_sw_context)
1124 raw_spin_lock_irqsave(&cpuctx->hrtimer_lock, flags);
1125 if (!cpuctx->hrtimer_active) {
1126 cpuctx->hrtimer_active = 1;
1127 hrtimer_forward_now(timer, cpuctx->hrtimer_interval);
1128 hrtimer_start_expires(timer, HRTIMER_MODE_ABS_PINNED_HARD);
1130 raw_spin_unlock_irqrestore(&cpuctx->hrtimer_lock, flags);
1135 void perf_pmu_disable(struct pmu *pmu)
1137 int *count = this_cpu_ptr(pmu->pmu_disable_count);
1139 pmu->pmu_disable(pmu);
1142 void perf_pmu_enable(struct pmu *pmu)
1144 int *count = this_cpu_ptr(pmu->pmu_disable_count);
1146 pmu->pmu_enable(pmu);
1149 static DEFINE_PER_CPU(struct list_head, active_ctx_list);
1152 * perf_event_ctx_activate(), perf_event_ctx_deactivate(), and
1153 * perf_event_task_tick() are fully serialized because they're strictly cpu
1154 * affine and perf_event_ctx{activate,deactivate} are called with IRQs
1155 * disabled, while perf_event_task_tick is called from IRQ context.
1157 static void perf_event_ctx_activate(struct perf_event_context *ctx)
1159 struct list_head *head = this_cpu_ptr(&active_ctx_list);
1161 lockdep_assert_irqs_disabled();
1163 WARN_ON(!list_empty(&ctx->active_ctx_list));
1165 list_add(&ctx->active_ctx_list, head);
1168 static void perf_event_ctx_deactivate(struct perf_event_context *ctx)
1170 lockdep_assert_irqs_disabled();
1172 WARN_ON(list_empty(&ctx->active_ctx_list));
1174 list_del_init(&ctx->active_ctx_list);
1177 static void get_ctx(struct perf_event_context *ctx)
1179 refcount_inc(&ctx->refcount);
1182 static void *alloc_task_ctx_data(struct pmu *pmu)
1184 if (pmu->task_ctx_cache)
1185 return kmem_cache_zalloc(pmu->task_ctx_cache, GFP_KERNEL);
1190 static void free_task_ctx_data(struct pmu *pmu, void *task_ctx_data)
1192 if (pmu->task_ctx_cache && task_ctx_data)
1193 kmem_cache_free(pmu->task_ctx_cache, task_ctx_data);
1196 static void free_ctx(struct rcu_head *head)
1198 struct perf_event_context *ctx;
1200 ctx = container_of(head, struct perf_event_context, rcu_head);
1201 free_task_ctx_data(ctx->pmu, ctx->task_ctx_data);
1205 static void put_ctx(struct perf_event_context *ctx)
1207 if (refcount_dec_and_test(&ctx->refcount)) {
1208 if (ctx->parent_ctx)
1209 put_ctx(ctx->parent_ctx);
1210 if (ctx->task && ctx->task != TASK_TOMBSTONE)
1211 put_task_struct(ctx->task);
1212 call_rcu(&ctx->rcu_head, free_ctx);
1217 * Because of perf_event::ctx migration in sys_perf_event_open::move_group and
1218 * perf_pmu_migrate_context() we need some magic.
1220 * Those places that change perf_event::ctx will hold both
1221 * perf_event_ctx::mutex of the 'old' and 'new' ctx value.
1223 * Lock ordering is by mutex address. There are two other sites where
1224 * perf_event_context::mutex nests and those are:
1226 * - perf_event_exit_task_context() [ child , 0 ]
1227 * perf_event_exit_event()
1228 * put_event() [ parent, 1 ]
1230 * - perf_event_init_context() [ parent, 0 ]
1231 * inherit_task_group()
1234 * perf_event_alloc()
1236 * perf_try_init_event() [ child , 1 ]
1238 * While it appears there is an obvious deadlock here -- the parent and child
1239 * nesting levels are inverted between the two. This is in fact safe because
1240 * life-time rules separate them. That is an exiting task cannot fork, and a
1241 * spawning task cannot (yet) exit.
1243 * But remember that these are parent<->child context relations, and
1244 * migration does not affect children, therefore these two orderings should not
1247 * The change in perf_event::ctx does not affect children (as claimed above)
1248 * because the sys_perf_event_open() case will install a new event and break
1249 * the ctx parent<->child relation, and perf_pmu_migrate_context() is only
1250 * concerned with cpuctx and that doesn't have children.
1252 * The places that change perf_event::ctx will issue:
1254 * perf_remove_from_context();
1255 * synchronize_rcu();
1256 * perf_install_in_context();
1258 * to affect the change. The remove_from_context() + synchronize_rcu() should
1259 * quiesce the event, after which we can install it in the new location. This
1260 * means that only external vectors (perf_fops, prctl) can perturb the event
1261 * while in transit. Therefore all such accessors should also acquire
1262 * perf_event_context::mutex to serialize against this.
1264 * However; because event->ctx can change while we're waiting to acquire
1265 * ctx->mutex we must be careful and use the below perf_event_ctx_lock()
1270 * task_struct::perf_event_mutex
1271 * perf_event_context::mutex
1272 * perf_event::child_mutex;
1273 * perf_event_context::lock
1274 * perf_event::mmap_mutex
1276 * perf_addr_filters_head::lock
1280 * cpuctx->mutex / perf_event_context::mutex
1282 static struct perf_event_context *
1283 perf_event_ctx_lock_nested(struct perf_event *event, int nesting)
1285 struct perf_event_context *ctx;
1289 ctx = READ_ONCE(event->ctx);
1290 if (!refcount_inc_not_zero(&ctx->refcount)) {
1296 mutex_lock_nested(&ctx->mutex, nesting);
1297 if (event->ctx != ctx) {
1298 mutex_unlock(&ctx->mutex);
1306 static inline struct perf_event_context *
1307 perf_event_ctx_lock(struct perf_event *event)
1309 return perf_event_ctx_lock_nested(event, 0);
1312 static void perf_event_ctx_unlock(struct perf_event *event,
1313 struct perf_event_context *ctx)
1315 mutex_unlock(&ctx->mutex);
1320 * This must be done under the ctx->lock, such as to serialize against
1321 * context_equiv(), therefore we cannot call put_ctx() since that might end up
1322 * calling scheduler related locks and ctx->lock nests inside those.
1324 static __must_check struct perf_event_context *
1325 unclone_ctx(struct perf_event_context *ctx)
1327 struct perf_event_context *parent_ctx = ctx->parent_ctx;
1329 lockdep_assert_held(&ctx->lock);
1332 ctx->parent_ctx = NULL;
1338 static u32 perf_event_pid_type(struct perf_event *event, struct task_struct *p,
1343 * only top level events have the pid namespace they were created in
1346 event = event->parent;
1348 nr = __task_pid_nr_ns(p, type, event->ns);
1349 /* avoid -1 if it is idle thread or runs in another ns */
1350 if (!nr && !pid_alive(p))
1355 static u32 perf_event_pid(struct perf_event *event, struct task_struct *p)
1357 return perf_event_pid_type(event, p, PIDTYPE_TGID);
1360 static u32 perf_event_tid(struct perf_event *event, struct task_struct *p)
1362 return perf_event_pid_type(event, p, PIDTYPE_PID);
1366 * If we inherit events we want to return the parent event id
1369 static u64 primary_event_id(struct perf_event *event)
1374 id = event->parent->id;
1380 * Get the perf_event_context for a task and lock it.
1382 * This has to cope with the fact that until it is locked,
1383 * the context could get moved to another task.
1385 static struct perf_event_context *
1386 perf_lock_task_context(struct task_struct *task, int ctxn, unsigned long *flags)
1388 struct perf_event_context *ctx;
1392 * One of the few rules of preemptible RCU is that one cannot do
1393 * rcu_read_unlock() while holding a scheduler (or nested) lock when
1394 * part of the read side critical section was irqs-enabled -- see
1395 * rcu_read_unlock_special().
1397 * Since ctx->lock nests under rq->lock we must ensure the entire read
1398 * side critical section has interrupts disabled.
1400 local_irq_save(*flags);
1402 ctx = rcu_dereference(task->perf_event_ctxp[ctxn]);
1405 * If this context is a clone of another, it might
1406 * get swapped for another underneath us by
1407 * perf_event_task_sched_out, though the
1408 * rcu_read_lock() protects us from any context
1409 * getting freed. Lock the context and check if it
1410 * got swapped before we could get the lock, and retry
1411 * if so. If we locked the right context, then it
1412 * can't get swapped on us any more.
1414 raw_spin_lock(&ctx->lock);
1415 if (ctx != rcu_dereference(task->perf_event_ctxp[ctxn])) {
1416 raw_spin_unlock(&ctx->lock);
1418 local_irq_restore(*flags);
1422 if (ctx->task == TASK_TOMBSTONE ||
1423 !refcount_inc_not_zero(&ctx->refcount)) {
1424 raw_spin_unlock(&ctx->lock);
1427 WARN_ON_ONCE(ctx->task != task);
1432 local_irq_restore(*flags);
1437 * Get the context for a task and increment its pin_count so it
1438 * can't get swapped to another task. This also increments its
1439 * reference count so that the context can't get freed.
1441 static struct perf_event_context *
1442 perf_pin_task_context(struct task_struct *task, int ctxn)
1444 struct perf_event_context *ctx;
1445 unsigned long flags;
1447 ctx = perf_lock_task_context(task, ctxn, &flags);
1450 raw_spin_unlock_irqrestore(&ctx->lock, flags);
1455 static void perf_unpin_context(struct perf_event_context *ctx)
1457 unsigned long flags;
1459 raw_spin_lock_irqsave(&ctx->lock, flags);
1461 raw_spin_unlock_irqrestore(&ctx->lock, flags);
1465 * Update the record of the current time in a context.
1467 static void __update_context_time(struct perf_event_context *ctx, bool adv)
1469 u64 now = perf_clock();
1472 ctx->time += now - ctx->timestamp;
1473 ctx->timestamp = now;
1476 * The above: time' = time + (now - timestamp), can be re-arranged
1477 * into: time` = now + (time - timestamp), which gives a single value
1478 * offset to compute future time without locks on.
1480 * See perf_event_time_now(), which can be used from NMI context where
1481 * it's (obviously) not possible to acquire ctx->lock in order to read
1482 * both the above values in a consistent manner.
1484 WRITE_ONCE(ctx->timeoffset, ctx->time - ctx->timestamp);
1487 static void update_context_time(struct perf_event_context *ctx)
1489 __update_context_time(ctx, true);
1492 static u64 perf_event_time(struct perf_event *event)
1494 struct perf_event_context *ctx = event->ctx;
1499 if (is_cgroup_event(event))
1500 return perf_cgroup_event_time(event);
1505 static u64 perf_event_time_now(struct perf_event *event, u64 now)
1507 struct perf_event_context *ctx = event->ctx;
1512 if (is_cgroup_event(event))
1513 return perf_cgroup_event_time_now(event, now);
1515 if (!(__load_acquire(&ctx->is_active) & EVENT_TIME))
1518 now += READ_ONCE(ctx->timeoffset);
1522 static enum event_type_t get_event_type(struct perf_event *event)
1524 struct perf_event_context *ctx = event->ctx;
1525 enum event_type_t event_type;
1527 lockdep_assert_held(&ctx->lock);
1530 * It's 'group type', really, because if our group leader is
1531 * pinned, so are we.
1533 if (event->group_leader != event)
1534 event = event->group_leader;
1536 event_type = event->attr.pinned ? EVENT_PINNED : EVENT_FLEXIBLE;
1538 event_type |= EVENT_CPU;
1544 * Helper function to initialize event group nodes.
1546 static void init_event_group(struct perf_event *event)
1548 RB_CLEAR_NODE(&event->group_node);
1549 event->group_index = 0;
1553 * Extract pinned or flexible groups from the context
1554 * based on event attrs bits.
1556 static struct perf_event_groups *
1557 get_event_groups(struct perf_event *event, struct perf_event_context *ctx)
1559 if (event->attr.pinned)
1560 return &ctx->pinned_groups;
1562 return &ctx->flexible_groups;
1566 * Helper function to initializes perf_event_group trees.
1568 static void perf_event_groups_init(struct perf_event_groups *groups)
1570 groups->tree = RB_ROOT;
1574 static inline struct cgroup *event_cgroup(const struct perf_event *event)
1576 struct cgroup *cgroup = NULL;
1578 #ifdef CONFIG_CGROUP_PERF
1580 cgroup = event->cgrp->css.cgroup;
1587 * Compare function for event groups;
1589 * Implements complex key that first sorts by CPU and then by virtual index
1590 * which provides ordering when rotating groups for the same CPU.
1592 static __always_inline int
1593 perf_event_groups_cmp(const int left_cpu, const struct cgroup *left_cgroup,
1594 const u64 left_group_index, const struct perf_event *right)
1596 if (left_cpu < right->cpu)
1598 if (left_cpu > right->cpu)
1601 #ifdef CONFIG_CGROUP_PERF
1603 const struct cgroup *right_cgroup = event_cgroup(right);
1605 if (left_cgroup != right_cgroup) {
1608 * Left has no cgroup but right does, no
1609 * cgroups come first.
1613 if (!right_cgroup) {
1615 * Right has no cgroup but left does, no
1616 * cgroups come first.
1620 /* Two dissimilar cgroups, order by id. */
1621 if (cgroup_id(left_cgroup) < cgroup_id(right_cgroup))
1629 if (left_group_index < right->group_index)
1631 if (left_group_index > right->group_index)
1637 #define __node_2_pe(node) \
1638 rb_entry((node), struct perf_event, group_node)
1640 static inline bool __group_less(struct rb_node *a, const struct rb_node *b)
1642 struct perf_event *e = __node_2_pe(a);
1643 return perf_event_groups_cmp(e->cpu, event_cgroup(e), e->group_index,
1644 __node_2_pe(b)) < 0;
1647 struct __group_key {
1649 struct cgroup *cgroup;
1652 static inline int __group_cmp(const void *key, const struct rb_node *node)
1654 const struct __group_key *a = key;
1655 const struct perf_event *b = __node_2_pe(node);
1657 /* partial/subtree match: @cpu, @cgroup; ignore: @group_index */
1658 return perf_event_groups_cmp(a->cpu, a->cgroup, b->group_index, b);
1662 * Insert @event into @groups' tree; using {@event->cpu, ++@groups->index} for
1663 * key (see perf_event_groups_less). This places it last inside the CPU
1667 perf_event_groups_insert(struct perf_event_groups *groups,
1668 struct perf_event *event)
1670 event->group_index = ++groups->index;
1672 rb_add(&event->group_node, &groups->tree, __group_less);
1676 * Helper function to insert event into the pinned or flexible groups.
1679 add_event_to_groups(struct perf_event *event, struct perf_event_context *ctx)
1681 struct perf_event_groups *groups;
1683 groups = get_event_groups(event, ctx);
1684 perf_event_groups_insert(groups, event);
1688 * Delete a group from a tree.
1691 perf_event_groups_delete(struct perf_event_groups *groups,
1692 struct perf_event *event)
1694 WARN_ON_ONCE(RB_EMPTY_NODE(&event->group_node) ||
1695 RB_EMPTY_ROOT(&groups->tree));
1697 rb_erase(&event->group_node, &groups->tree);
1698 init_event_group(event);
1702 * Helper function to delete event from its groups.
1705 del_event_from_groups(struct perf_event *event, struct perf_event_context *ctx)
1707 struct perf_event_groups *groups;
1709 groups = get_event_groups(event, ctx);
1710 perf_event_groups_delete(groups, event);
1714 * Get the leftmost event in the cpu/cgroup subtree.
1716 static struct perf_event *
1717 perf_event_groups_first(struct perf_event_groups *groups, int cpu,
1718 struct cgroup *cgrp)
1720 struct __group_key key = {
1724 struct rb_node *node;
1726 node = rb_find_first(&key, &groups->tree, __group_cmp);
1728 return __node_2_pe(node);
1734 * Like rb_entry_next_safe() for the @cpu subtree.
1736 static struct perf_event *
1737 perf_event_groups_next(struct perf_event *event)
1739 struct __group_key key = {
1741 .cgroup = event_cgroup(event),
1743 struct rb_node *next;
1745 next = rb_next_match(&key, &event->group_node, __group_cmp);
1747 return __node_2_pe(next);
1753 * Iterate through the whole groups tree.
1755 #define perf_event_groups_for_each(event, groups) \
1756 for (event = rb_entry_safe(rb_first(&((groups)->tree)), \
1757 typeof(*event), group_node); event; \
1758 event = rb_entry_safe(rb_next(&event->group_node), \
1759 typeof(*event), group_node))
1762 * Add an event from the lists for its context.
1763 * Must be called with ctx->mutex and ctx->lock held.
1766 list_add_event(struct perf_event *event, struct perf_event_context *ctx)
1768 lockdep_assert_held(&ctx->lock);
1770 WARN_ON_ONCE(event->attach_state & PERF_ATTACH_CONTEXT);
1771 event->attach_state |= PERF_ATTACH_CONTEXT;
1773 event->tstamp = perf_event_time(event);
1776 * If we're a stand alone event or group leader, we go to the context
1777 * list, group events are kept attached to the group so that
1778 * perf_group_detach can, at all times, locate all siblings.
1780 if (event->group_leader == event) {
1781 event->group_caps = event->event_caps;
1782 add_event_to_groups(event, ctx);
1785 list_add_rcu(&event->event_entry, &ctx->event_list);
1787 if (event->hw.flags & PERF_EVENT_FLAG_USER_READ_CNT)
1789 if (event->attr.inherit_stat)
1792 if (event->state > PERF_EVENT_STATE_OFF)
1793 perf_cgroup_event_enable(event, ctx);
1799 * Initialize event state based on the perf_event_attr::disabled.
1801 static inline void perf_event__state_init(struct perf_event *event)
1803 event->state = event->attr.disabled ? PERF_EVENT_STATE_OFF :
1804 PERF_EVENT_STATE_INACTIVE;
1807 static void __perf_event_read_size(struct perf_event *event, int nr_siblings)
1809 int entry = sizeof(u64); /* value */
1813 if (event->attr.read_format & PERF_FORMAT_TOTAL_TIME_ENABLED)
1814 size += sizeof(u64);
1816 if (event->attr.read_format & PERF_FORMAT_TOTAL_TIME_RUNNING)
1817 size += sizeof(u64);
1819 if (event->attr.read_format & PERF_FORMAT_ID)
1820 entry += sizeof(u64);
1822 if (event->attr.read_format & PERF_FORMAT_LOST)
1823 entry += sizeof(u64);
1825 if (event->attr.read_format & PERF_FORMAT_GROUP) {
1827 size += sizeof(u64);
1831 event->read_size = size;
1834 static void __perf_event_header_size(struct perf_event *event, u64 sample_type)
1836 struct perf_sample_data *data;
1839 if (sample_type & PERF_SAMPLE_IP)
1840 size += sizeof(data->ip);
1842 if (sample_type & PERF_SAMPLE_ADDR)
1843 size += sizeof(data->addr);
1845 if (sample_type & PERF_SAMPLE_PERIOD)
1846 size += sizeof(data->period);
1848 if (sample_type & PERF_SAMPLE_WEIGHT_TYPE)
1849 size += sizeof(data->weight.full);
1851 if (sample_type & PERF_SAMPLE_READ)
1852 size += event->read_size;
1854 if (sample_type & PERF_SAMPLE_DATA_SRC)
1855 size += sizeof(data->data_src.val);
1857 if (sample_type & PERF_SAMPLE_TRANSACTION)
1858 size += sizeof(data->txn);
1860 if (sample_type & PERF_SAMPLE_PHYS_ADDR)
1861 size += sizeof(data->phys_addr);
1863 if (sample_type & PERF_SAMPLE_CGROUP)
1864 size += sizeof(data->cgroup);
1866 if (sample_type & PERF_SAMPLE_DATA_PAGE_SIZE)
1867 size += sizeof(data->data_page_size);
1869 if (sample_type & PERF_SAMPLE_CODE_PAGE_SIZE)
1870 size += sizeof(data->code_page_size);
1872 event->header_size = size;
1876 * Called at perf_event creation and when events are attached/detached from a
1879 static void perf_event__header_size(struct perf_event *event)
1881 __perf_event_read_size(event,
1882 event->group_leader->nr_siblings);
1883 __perf_event_header_size(event, event->attr.sample_type);
1886 static void perf_event__id_header_size(struct perf_event *event)
1888 struct perf_sample_data *data;
1889 u64 sample_type = event->attr.sample_type;
1892 if (sample_type & PERF_SAMPLE_TID)
1893 size += sizeof(data->tid_entry);
1895 if (sample_type & PERF_SAMPLE_TIME)
1896 size += sizeof(data->time);
1898 if (sample_type & PERF_SAMPLE_IDENTIFIER)
1899 size += sizeof(data->id);
1901 if (sample_type & PERF_SAMPLE_ID)
1902 size += sizeof(data->id);
1904 if (sample_type & PERF_SAMPLE_STREAM_ID)
1905 size += sizeof(data->stream_id);
1907 if (sample_type & PERF_SAMPLE_CPU)
1908 size += sizeof(data->cpu_entry);
1910 event->id_header_size = size;
1913 static bool perf_event_validate_size(struct perf_event *event)
1916 * The values computed here will be over-written when we actually
1919 __perf_event_read_size(event, event->group_leader->nr_siblings + 1);
1920 __perf_event_header_size(event, event->attr.sample_type & ~PERF_SAMPLE_READ);
1921 perf_event__id_header_size(event);
1924 * Sum the lot; should not exceed the 64k limit we have on records.
1925 * Conservative limit to allow for callchains and other variable fields.
1927 if (event->read_size + event->header_size +
1928 event->id_header_size + sizeof(struct perf_event_header) >= 16*1024)
1934 static void perf_group_attach(struct perf_event *event)
1936 struct perf_event *group_leader = event->group_leader, *pos;
1938 lockdep_assert_held(&event->ctx->lock);
1941 * We can have double attach due to group movement in perf_event_open.
1943 if (event->attach_state & PERF_ATTACH_GROUP)
1946 event->attach_state |= PERF_ATTACH_GROUP;
1948 if (group_leader == event)
1951 WARN_ON_ONCE(group_leader->ctx != event->ctx);
1953 group_leader->group_caps &= event->event_caps;
1955 list_add_tail(&event->sibling_list, &group_leader->sibling_list);
1956 group_leader->nr_siblings++;
1958 perf_event__header_size(group_leader);
1960 for_each_sibling_event(pos, group_leader)
1961 perf_event__header_size(pos);
1965 * Remove an event from the lists for its context.
1966 * Must be called with ctx->mutex and ctx->lock held.
1969 list_del_event(struct perf_event *event, struct perf_event_context *ctx)
1971 WARN_ON_ONCE(event->ctx != ctx);
1972 lockdep_assert_held(&ctx->lock);
1975 * We can have double detach due to exit/hot-unplug + close.
1977 if (!(event->attach_state & PERF_ATTACH_CONTEXT))
1980 event->attach_state &= ~PERF_ATTACH_CONTEXT;
1983 if (event->hw.flags & PERF_EVENT_FLAG_USER_READ_CNT)
1985 if (event->attr.inherit_stat)
1988 list_del_rcu(&event->event_entry);
1990 if (event->group_leader == event)
1991 del_event_from_groups(event, ctx);
1994 * If event was in error state, then keep it
1995 * that way, otherwise bogus counts will be
1996 * returned on read(). The only way to get out
1997 * of error state is by explicit re-enabling
2000 if (event->state > PERF_EVENT_STATE_OFF) {
2001 perf_cgroup_event_disable(event, ctx);
2002 perf_event_set_state(event, PERF_EVENT_STATE_OFF);
2009 perf_aux_output_match(struct perf_event *event, struct perf_event *aux_event)
2011 if (!has_aux(aux_event))
2014 if (!event->pmu->aux_output_match)
2017 return event->pmu->aux_output_match(aux_event);
2020 static void put_event(struct perf_event *event);
2021 static void event_sched_out(struct perf_event *event,
2022 struct perf_cpu_context *cpuctx,
2023 struct perf_event_context *ctx);
2025 static void perf_put_aux_event(struct perf_event *event)
2027 struct perf_event_context *ctx = event->ctx;
2028 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
2029 struct perf_event *iter;
2032 * If event uses aux_event tear down the link
2034 if (event->aux_event) {
2035 iter = event->aux_event;
2036 event->aux_event = NULL;
2042 * If the event is an aux_event, tear down all links to
2043 * it from other events.
2045 for_each_sibling_event(iter, event->group_leader) {
2046 if (iter->aux_event != event)
2049 iter->aux_event = NULL;
2053 * If it's ACTIVE, schedule it out and put it into ERROR
2054 * state so that we don't try to schedule it again. Note
2055 * that perf_event_enable() will clear the ERROR status.
2057 event_sched_out(iter, cpuctx, ctx);
2058 perf_event_set_state(event, PERF_EVENT_STATE_ERROR);
2062 static bool perf_need_aux_event(struct perf_event *event)
2064 return !!event->attr.aux_output || !!event->attr.aux_sample_size;
2067 static int perf_get_aux_event(struct perf_event *event,
2068 struct perf_event *group_leader)
2071 * Our group leader must be an aux event if we want to be
2072 * an aux_output. This way, the aux event will precede its
2073 * aux_output events in the group, and therefore will always
2080 * aux_output and aux_sample_size are mutually exclusive.
2082 if (event->attr.aux_output && event->attr.aux_sample_size)
2085 if (event->attr.aux_output &&
2086 !perf_aux_output_match(event, group_leader))
2089 if (event->attr.aux_sample_size && !group_leader->pmu->snapshot_aux)
2092 if (!atomic_long_inc_not_zero(&group_leader->refcount))
2096 * Link aux_outputs to their aux event; this is undone in
2097 * perf_group_detach() by perf_put_aux_event(). When the
2098 * group in torn down, the aux_output events loose their
2099 * link to the aux_event and can't schedule any more.
2101 event->aux_event = group_leader;
2106 static inline struct list_head *get_event_list(struct perf_event *event)
2108 struct perf_event_context *ctx = event->ctx;
2109 return event->attr.pinned ? &ctx->pinned_active : &ctx->flexible_active;
2113 * Events that have PERF_EV_CAP_SIBLING require being part of a group and
2114 * cannot exist on their own, schedule them out and move them into the ERROR
2115 * state. Also see _perf_event_enable(), it will not be able to recover
2118 static inline void perf_remove_sibling_event(struct perf_event *event)
2120 struct perf_event_context *ctx = event->ctx;
2121 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
2123 event_sched_out(event, cpuctx, ctx);
2124 perf_event_set_state(event, PERF_EVENT_STATE_ERROR);
2127 static void perf_group_detach(struct perf_event *event)
2129 struct perf_event *leader = event->group_leader;
2130 struct perf_event *sibling, *tmp;
2131 struct perf_event_context *ctx = event->ctx;
2133 lockdep_assert_held(&ctx->lock);
2136 * We can have double detach due to exit/hot-unplug + close.
2138 if (!(event->attach_state & PERF_ATTACH_GROUP))
2141 event->attach_state &= ~PERF_ATTACH_GROUP;
2143 perf_put_aux_event(event);
2146 * If this is a sibling, remove it from its group.
2148 if (leader != event) {
2149 list_del_init(&event->sibling_list);
2150 event->group_leader->nr_siblings--;
2155 * If this was a group event with sibling events then
2156 * upgrade the siblings to singleton events by adding them
2157 * to whatever list we are on.
2159 list_for_each_entry_safe(sibling, tmp, &event->sibling_list, sibling_list) {
2161 if (sibling->event_caps & PERF_EV_CAP_SIBLING)
2162 perf_remove_sibling_event(sibling);
2164 sibling->group_leader = sibling;
2165 list_del_init(&sibling->sibling_list);
2167 /* Inherit group flags from the previous leader */
2168 sibling->group_caps = event->group_caps;
2170 if (!RB_EMPTY_NODE(&event->group_node)) {
2171 add_event_to_groups(sibling, event->ctx);
2173 if (sibling->state == PERF_EVENT_STATE_ACTIVE)
2174 list_add_tail(&sibling->active_list, get_event_list(sibling));
2177 WARN_ON_ONCE(sibling->ctx != event->ctx);
2181 for_each_sibling_event(tmp, leader)
2182 perf_event__header_size(tmp);
2184 perf_event__header_size(leader);
2187 static void sync_child_event(struct perf_event *child_event);
2189 static void perf_child_detach(struct perf_event *event)
2191 struct perf_event *parent_event = event->parent;
2193 if (!(event->attach_state & PERF_ATTACH_CHILD))
2196 event->attach_state &= ~PERF_ATTACH_CHILD;
2198 if (WARN_ON_ONCE(!parent_event))
2201 lockdep_assert_held(&parent_event->child_mutex);
2203 sync_child_event(event);
2204 list_del_init(&event->child_list);
2207 static bool is_orphaned_event(struct perf_event *event)
2209 return event->state == PERF_EVENT_STATE_DEAD;
2212 static inline int __pmu_filter_match(struct perf_event *event)
2214 struct pmu *pmu = event->pmu;
2215 return pmu->filter_match ? pmu->filter_match(event) : 1;
2219 * Check whether we should attempt to schedule an event group based on
2220 * PMU-specific filtering. An event group can consist of HW and SW events,
2221 * potentially with a SW leader, so we must check all the filters, to
2222 * determine whether a group is schedulable:
2224 static inline int pmu_filter_match(struct perf_event *event)
2226 struct perf_event *sibling;
2228 if (!__pmu_filter_match(event))
2231 for_each_sibling_event(sibling, event) {
2232 if (!__pmu_filter_match(sibling))
2240 event_filter_match(struct perf_event *event)
2242 return (event->cpu == -1 || event->cpu == smp_processor_id()) &&
2243 perf_cgroup_match(event) && pmu_filter_match(event);
2247 event_sched_out(struct perf_event *event,
2248 struct perf_cpu_context *cpuctx,
2249 struct perf_event_context *ctx)
2251 enum perf_event_state state = PERF_EVENT_STATE_INACTIVE;
2253 WARN_ON_ONCE(event->ctx != ctx);
2254 lockdep_assert_held(&ctx->lock);
2256 if (event->state != PERF_EVENT_STATE_ACTIVE)
2260 * Asymmetry; we only schedule events _IN_ through ctx_sched_in(), but
2261 * we can schedule events _OUT_ individually through things like
2262 * __perf_remove_from_context().
2264 list_del_init(&event->active_list);
2266 perf_pmu_disable(event->pmu);
2268 event->pmu->del(event, 0);
2271 if (READ_ONCE(event->pending_disable) >= 0) {
2272 WRITE_ONCE(event->pending_disable, -1);
2273 perf_cgroup_event_disable(event, ctx);
2274 state = PERF_EVENT_STATE_OFF;
2276 perf_event_set_state(event, state);
2278 if (!is_software_event(event))
2279 cpuctx->active_oncpu--;
2280 if (!--ctx->nr_active)
2281 perf_event_ctx_deactivate(ctx);
2282 if (event->attr.freq && event->attr.sample_freq)
2284 if (event->attr.exclusive || !cpuctx->active_oncpu)
2285 cpuctx->exclusive = 0;
2287 perf_pmu_enable(event->pmu);
2291 group_sched_out(struct perf_event *group_event,
2292 struct perf_cpu_context *cpuctx,
2293 struct perf_event_context *ctx)
2295 struct perf_event *event;
2297 if (group_event->state != PERF_EVENT_STATE_ACTIVE)
2300 perf_pmu_disable(ctx->pmu);
2302 event_sched_out(group_event, cpuctx, ctx);
2305 * Schedule out siblings (if any):
2307 for_each_sibling_event(event, group_event)
2308 event_sched_out(event, cpuctx, ctx);
2310 perf_pmu_enable(ctx->pmu);
2313 #define DETACH_GROUP 0x01UL
2314 #define DETACH_CHILD 0x02UL
2317 * Cross CPU call to remove a performance event
2319 * We disable the event on the hardware level first. After that we
2320 * remove it from the context list.
2323 __perf_remove_from_context(struct perf_event *event,
2324 struct perf_cpu_context *cpuctx,
2325 struct perf_event_context *ctx,
2328 unsigned long flags = (unsigned long)info;
2330 if (ctx->is_active & EVENT_TIME) {
2331 update_context_time(ctx);
2332 update_cgrp_time_from_cpuctx(cpuctx, false);
2335 event_sched_out(event, cpuctx, ctx);
2336 if (flags & DETACH_GROUP)
2337 perf_group_detach(event);
2338 if (flags & DETACH_CHILD)
2339 perf_child_detach(event);
2340 list_del_event(event, ctx);
2342 if (!ctx->nr_events && ctx->is_active) {
2343 if (ctx == &cpuctx->ctx)
2344 update_cgrp_time_from_cpuctx(cpuctx, true);
2347 ctx->rotate_necessary = 0;
2349 WARN_ON_ONCE(cpuctx->task_ctx != ctx);
2350 cpuctx->task_ctx = NULL;
2356 * Remove the event from a task's (or a CPU's) list of events.
2358 * If event->ctx is a cloned context, callers must make sure that
2359 * every task struct that event->ctx->task could possibly point to
2360 * remains valid. This is OK when called from perf_release since
2361 * that only calls us on the top-level context, which can't be a clone.
2362 * When called from perf_event_exit_task, it's OK because the
2363 * context has been detached from its task.
2365 static void perf_remove_from_context(struct perf_event *event, unsigned long flags)
2367 struct perf_event_context *ctx = event->ctx;
2369 lockdep_assert_held(&ctx->mutex);
2372 * Because of perf_event_exit_task(), perf_remove_from_context() ought
2373 * to work in the face of TASK_TOMBSTONE, unlike every other
2374 * event_function_call() user.
2376 raw_spin_lock_irq(&ctx->lock);
2378 * Cgroup events are per-cpu events, and must IPI because of
2381 if (!ctx->is_active && !is_cgroup_event(event)) {
2382 __perf_remove_from_context(event, __get_cpu_context(ctx),
2383 ctx, (void *)flags);
2384 raw_spin_unlock_irq(&ctx->lock);
2387 raw_spin_unlock_irq(&ctx->lock);
2389 event_function_call(event, __perf_remove_from_context, (void *)flags);
2393 * Cross CPU call to disable a performance event
2395 static void __perf_event_disable(struct perf_event *event,
2396 struct perf_cpu_context *cpuctx,
2397 struct perf_event_context *ctx,
2400 if (event->state < PERF_EVENT_STATE_INACTIVE)
2403 if (ctx->is_active & EVENT_TIME) {
2404 update_context_time(ctx);
2405 update_cgrp_time_from_event(event);
2408 if (event == event->group_leader)
2409 group_sched_out(event, cpuctx, ctx);
2411 event_sched_out(event, cpuctx, ctx);
2413 perf_event_set_state(event, PERF_EVENT_STATE_OFF);
2414 perf_cgroup_event_disable(event, ctx);
2420 * If event->ctx is a cloned context, callers must make sure that
2421 * every task struct that event->ctx->task could possibly point to
2422 * remains valid. This condition is satisfied when called through
2423 * perf_event_for_each_child or perf_event_for_each because they
2424 * hold the top-level event's child_mutex, so any descendant that
2425 * goes to exit will block in perf_event_exit_event().
2427 * When called from perf_pending_event it's OK because event->ctx
2428 * is the current context on this CPU and preemption is disabled,
2429 * hence we can't get into perf_event_task_sched_out for this context.
2431 static void _perf_event_disable(struct perf_event *event)
2433 struct perf_event_context *ctx = event->ctx;
2435 raw_spin_lock_irq(&ctx->lock);
2436 if (event->state <= PERF_EVENT_STATE_OFF) {
2437 raw_spin_unlock_irq(&ctx->lock);
2440 raw_spin_unlock_irq(&ctx->lock);
2442 event_function_call(event, __perf_event_disable, NULL);
2445 void perf_event_disable_local(struct perf_event *event)
2447 event_function_local(event, __perf_event_disable, NULL);
2451 * Strictly speaking kernel users cannot create groups and therefore this
2452 * interface does not need the perf_event_ctx_lock() magic.
2454 void perf_event_disable(struct perf_event *event)
2456 struct perf_event_context *ctx;
2458 ctx = perf_event_ctx_lock(event);
2459 _perf_event_disable(event);
2460 perf_event_ctx_unlock(event, ctx);
2462 EXPORT_SYMBOL_GPL(perf_event_disable);
2464 void perf_event_disable_inatomic(struct perf_event *event)
2466 WRITE_ONCE(event->pending_disable, smp_processor_id());
2467 /* can fail, see perf_pending_event_disable() */
2468 irq_work_queue(&event->pending);
2471 #define MAX_INTERRUPTS (~0ULL)
2473 static void perf_log_throttle(struct perf_event *event, int enable);
2474 static void perf_log_itrace_start(struct perf_event *event);
2477 event_sched_in(struct perf_event *event,
2478 struct perf_cpu_context *cpuctx,
2479 struct perf_event_context *ctx)
2483 WARN_ON_ONCE(event->ctx != ctx);
2485 lockdep_assert_held(&ctx->lock);
2487 if (event->state <= PERF_EVENT_STATE_OFF)
2490 WRITE_ONCE(event->oncpu, smp_processor_id());
2492 * Order event::oncpu write to happen before the ACTIVE state is
2493 * visible. This allows perf_event_{stop,read}() to observe the correct
2494 * ->oncpu if it sees ACTIVE.
2497 perf_event_set_state(event, PERF_EVENT_STATE_ACTIVE);
2500 * Unthrottle events, since we scheduled we might have missed several
2501 * ticks already, also for a heavily scheduling task there is little
2502 * guarantee it'll get a tick in a timely manner.
2504 if (unlikely(event->hw.interrupts == MAX_INTERRUPTS)) {
2505 perf_log_throttle(event, 1);
2506 event->hw.interrupts = 0;
2509 perf_pmu_disable(event->pmu);
2511 perf_log_itrace_start(event);
2513 if (event->pmu->add(event, PERF_EF_START)) {
2514 perf_event_set_state(event, PERF_EVENT_STATE_INACTIVE);
2520 if (!is_software_event(event))
2521 cpuctx->active_oncpu++;
2522 if (!ctx->nr_active++)
2523 perf_event_ctx_activate(ctx);
2524 if (event->attr.freq && event->attr.sample_freq)
2527 if (event->attr.exclusive)
2528 cpuctx->exclusive = 1;
2531 perf_pmu_enable(event->pmu);
2537 group_sched_in(struct perf_event *group_event,
2538 struct perf_cpu_context *cpuctx,
2539 struct perf_event_context *ctx)
2541 struct perf_event *event, *partial_group = NULL;
2542 struct pmu *pmu = ctx->pmu;
2544 if (group_event->state == PERF_EVENT_STATE_OFF)
2547 pmu->start_txn(pmu, PERF_PMU_TXN_ADD);
2549 if (event_sched_in(group_event, cpuctx, ctx))
2553 * Schedule in siblings as one group (if any):
2555 for_each_sibling_event(event, group_event) {
2556 if (event_sched_in(event, cpuctx, ctx)) {
2557 partial_group = event;
2562 if (!pmu->commit_txn(pmu))
2567 * Groups can be scheduled in as one unit only, so undo any
2568 * partial group before returning:
2569 * The events up to the failed event are scheduled out normally.
2571 for_each_sibling_event(event, group_event) {
2572 if (event == partial_group)
2575 event_sched_out(event, cpuctx, ctx);
2577 event_sched_out(group_event, cpuctx, ctx);
2580 pmu->cancel_txn(pmu);
2585 * Work out whether we can put this event group on the CPU now.
2587 static int group_can_go_on(struct perf_event *event,
2588 struct perf_cpu_context *cpuctx,
2592 * Groups consisting entirely of software events can always go on.
2594 if (event->group_caps & PERF_EV_CAP_SOFTWARE)
2597 * If an exclusive group is already on, no other hardware
2600 if (cpuctx->exclusive)
2603 * If this group is exclusive and there are already
2604 * events on the CPU, it can't go on.
2606 if (event->attr.exclusive && !list_empty(get_event_list(event)))
2609 * Otherwise, try to add it if all previous groups were able
2615 static void add_event_to_ctx(struct perf_event *event,
2616 struct perf_event_context *ctx)
2618 list_add_event(event, ctx);
2619 perf_group_attach(event);
2622 static void ctx_sched_out(struct perf_event_context *ctx,
2623 struct perf_cpu_context *cpuctx,
2624 enum event_type_t event_type);
2626 ctx_sched_in(struct perf_event_context *ctx,
2627 struct perf_cpu_context *cpuctx,
2628 enum event_type_t event_type);
2630 static void task_ctx_sched_out(struct perf_cpu_context *cpuctx,
2631 struct perf_event_context *ctx,
2632 enum event_type_t event_type)
2634 if (!cpuctx->task_ctx)
2637 if (WARN_ON_ONCE(ctx != cpuctx->task_ctx))
2640 ctx_sched_out(ctx, cpuctx, event_type);
2643 static void perf_event_sched_in(struct perf_cpu_context *cpuctx,
2644 struct perf_event_context *ctx)
2646 cpu_ctx_sched_in(cpuctx, EVENT_PINNED);
2648 ctx_sched_in(ctx, cpuctx, EVENT_PINNED);
2649 cpu_ctx_sched_in(cpuctx, EVENT_FLEXIBLE);
2651 ctx_sched_in(ctx, cpuctx, EVENT_FLEXIBLE);
2655 * We want to maintain the following priority of scheduling:
2656 * - CPU pinned (EVENT_CPU | EVENT_PINNED)
2657 * - task pinned (EVENT_PINNED)
2658 * - CPU flexible (EVENT_CPU | EVENT_FLEXIBLE)
2659 * - task flexible (EVENT_FLEXIBLE).
2661 * In order to avoid unscheduling and scheduling back in everything every
2662 * time an event is added, only do it for the groups of equal priority and
2665 * This can be called after a batch operation on task events, in which case
2666 * event_type is a bit mask of the types of events involved. For CPU events,
2667 * event_type is only either EVENT_PINNED or EVENT_FLEXIBLE.
2669 static void ctx_resched(struct perf_cpu_context *cpuctx,
2670 struct perf_event_context *task_ctx,
2671 enum event_type_t event_type)
2673 enum event_type_t ctx_event_type;
2674 bool cpu_event = !!(event_type & EVENT_CPU);
2677 * If pinned groups are involved, flexible groups also need to be
2680 if (event_type & EVENT_PINNED)
2681 event_type |= EVENT_FLEXIBLE;
2683 ctx_event_type = event_type & EVENT_ALL;
2685 perf_pmu_disable(cpuctx->ctx.pmu);
2687 task_ctx_sched_out(cpuctx, task_ctx, event_type);
2690 * Decide which cpu ctx groups to schedule out based on the types
2691 * of events that caused rescheduling:
2692 * - EVENT_CPU: schedule out corresponding groups;
2693 * - EVENT_PINNED task events: schedule out EVENT_FLEXIBLE groups;
2694 * - otherwise, do nothing more.
2697 cpu_ctx_sched_out(cpuctx, ctx_event_type);
2698 else if (ctx_event_type & EVENT_PINNED)
2699 cpu_ctx_sched_out(cpuctx, EVENT_FLEXIBLE);
2701 perf_event_sched_in(cpuctx, task_ctx);
2702 perf_pmu_enable(cpuctx->ctx.pmu);
2705 void perf_pmu_resched(struct pmu *pmu)
2707 struct perf_cpu_context *cpuctx = this_cpu_ptr(pmu->pmu_cpu_context);
2708 struct perf_event_context *task_ctx = cpuctx->task_ctx;
2710 perf_ctx_lock(cpuctx, task_ctx);
2711 ctx_resched(cpuctx, task_ctx, EVENT_ALL|EVENT_CPU);
2712 perf_ctx_unlock(cpuctx, task_ctx);
2716 * Cross CPU call to install and enable a performance event
2718 * Very similar to remote_function() + event_function() but cannot assume that
2719 * things like ctx->is_active and cpuctx->task_ctx are set.
2721 static int __perf_install_in_context(void *info)
2723 struct perf_event *event = info;
2724 struct perf_event_context *ctx = event->ctx;
2725 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
2726 struct perf_event_context *task_ctx = cpuctx->task_ctx;
2727 bool reprogram = true;
2730 raw_spin_lock(&cpuctx->ctx.lock);
2732 raw_spin_lock(&ctx->lock);
2735 reprogram = (ctx->task == current);
2738 * If the task is running, it must be running on this CPU,
2739 * otherwise we cannot reprogram things.
2741 * If its not running, we don't care, ctx->lock will
2742 * serialize against it becoming runnable.
2744 if (task_curr(ctx->task) && !reprogram) {
2749 WARN_ON_ONCE(reprogram && cpuctx->task_ctx && cpuctx->task_ctx != ctx);
2750 } else if (task_ctx) {
2751 raw_spin_lock(&task_ctx->lock);
2754 #ifdef CONFIG_CGROUP_PERF
2755 if (event->state > PERF_EVENT_STATE_OFF && is_cgroup_event(event)) {
2757 * If the current cgroup doesn't match the event's
2758 * cgroup, we should not try to schedule it.
2760 struct perf_cgroup *cgrp = perf_cgroup_from_task(current, ctx);
2761 reprogram = cgroup_is_descendant(cgrp->css.cgroup,
2762 event->cgrp->css.cgroup);
2767 ctx_sched_out(ctx, cpuctx, EVENT_TIME);
2768 add_event_to_ctx(event, ctx);
2769 ctx_resched(cpuctx, task_ctx, get_event_type(event));
2771 add_event_to_ctx(event, ctx);
2775 perf_ctx_unlock(cpuctx, task_ctx);
2780 static bool exclusive_event_installable(struct perf_event *event,
2781 struct perf_event_context *ctx);
2784 * Attach a performance event to a context.
2786 * Very similar to event_function_call, see comment there.
2789 perf_install_in_context(struct perf_event_context *ctx,
2790 struct perf_event *event,
2793 struct task_struct *task = READ_ONCE(ctx->task);
2795 lockdep_assert_held(&ctx->mutex);
2797 WARN_ON_ONCE(!exclusive_event_installable(event, ctx));
2799 if (event->cpu != -1)
2803 * Ensures that if we can observe event->ctx, both the event and ctx
2804 * will be 'complete'. See perf_iterate_sb_cpu().
2806 smp_store_release(&event->ctx, ctx);
2809 * perf_event_attr::disabled events will not run and can be initialized
2810 * without IPI. Except when this is the first event for the context, in
2811 * that case we need the magic of the IPI to set ctx->is_active.
2812 * Similarly, cgroup events for the context also needs the IPI to
2813 * manipulate the cgrp_cpuctx_list.
2815 * The IOC_ENABLE that is sure to follow the creation of a disabled
2816 * event will issue the IPI and reprogram the hardware.
2818 if (__perf_effective_state(event) == PERF_EVENT_STATE_OFF &&
2819 ctx->nr_events && !is_cgroup_event(event)) {
2820 raw_spin_lock_irq(&ctx->lock);
2821 if (ctx->task == TASK_TOMBSTONE) {
2822 raw_spin_unlock_irq(&ctx->lock);
2825 add_event_to_ctx(event, ctx);
2826 raw_spin_unlock_irq(&ctx->lock);
2831 cpu_function_call(cpu, __perf_install_in_context, event);
2836 * Should not happen, we validate the ctx is still alive before calling.
2838 if (WARN_ON_ONCE(task == TASK_TOMBSTONE))
2842 * Installing events is tricky because we cannot rely on ctx->is_active
2843 * to be set in case this is the nr_events 0 -> 1 transition.
2845 * Instead we use task_curr(), which tells us if the task is running.
2846 * However, since we use task_curr() outside of rq::lock, we can race
2847 * against the actual state. This means the result can be wrong.
2849 * If we get a false positive, we retry, this is harmless.
2851 * If we get a false negative, things are complicated. If we are after
2852 * perf_event_context_sched_in() ctx::lock will serialize us, and the
2853 * value must be correct. If we're before, it doesn't matter since
2854 * perf_event_context_sched_in() will program the counter.
2856 * However, this hinges on the remote context switch having observed
2857 * our task->perf_event_ctxp[] store, such that it will in fact take
2858 * ctx::lock in perf_event_context_sched_in().
2860 * We do this by task_function_call(), if the IPI fails to hit the task
2861 * we know any future context switch of task must see the
2862 * perf_event_ctpx[] store.
2866 * This smp_mb() orders the task->perf_event_ctxp[] store with the
2867 * task_cpu() load, such that if the IPI then does not find the task
2868 * running, a future context switch of that task must observe the
2873 if (!task_function_call(task, __perf_install_in_context, event))
2876 raw_spin_lock_irq(&ctx->lock);
2878 if (WARN_ON_ONCE(task == TASK_TOMBSTONE)) {
2880 * Cannot happen because we already checked above (which also
2881 * cannot happen), and we hold ctx->mutex, which serializes us
2882 * against perf_event_exit_task_context().
2884 raw_spin_unlock_irq(&ctx->lock);
2888 * If the task is not running, ctx->lock will avoid it becoming so,
2889 * thus we can safely install the event.
2891 if (task_curr(task)) {
2892 raw_spin_unlock_irq(&ctx->lock);
2895 add_event_to_ctx(event, ctx);
2896 raw_spin_unlock_irq(&ctx->lock);
2900 * Cross CPU call to enable a performance event
2902 static void __perf_event_enable(struct perf_event *event,
2903 struct perf_cpu_context *cpuctx,
2904 struct perf_event_context *ctx,
2907 struct perf_event *leader = event->group_leader;
2908 struct perf_event_context *task_ctx;
2910 if (event->state >= PERF_EVENT_STATE_INACTIVE ||
2911 event->state <= PERF_EVENT_STATE_ERROR)
2915 ctx_sched_out(ctx, cpuctx, EVENT_TIME);
2917 perf_event_set_state(event, PERF_EVENT_STATE_INACTIVE);
2918 perf_cgroup_event_enable(event, ctx);
2920 if (!ctx->is_active)
2923 if (!event_filter_match(event)) {
2924 ctx_sched_in(ctx, cpuctx, EVENT_TIME);
2929 * If the event is in a group and isn't the group leader,
2930 * then don't put it on unless the group is on.
2932 if (leader != event && leader->state != PERF_EVENT_STATE_ACTIVE) {
2933 ctx_sched_in(ctx, cpuctx, EVENT_TIME);
2937 task_ctx = cpuctx->task_ctx;
2939 WARN_ON_ONCE(task_ctx != ctx);
2941 ctx_resched(cpuctx, task_ctx, get_event_type(event));
2947 * If event->ctx is a cloned context, callers must make sure that
2948 * every task struct that event->ctx->task could possibly point to
2949 * remains valid. This condition is satisfied when called through
2950 * perf_event_for_each_child or perf_event_for_each as described
2951 * for perf_event_disable.
2953 static void _perf_event_enable(struct perf_event *event)
2955 struct perf_event_context *ctx = event->ctx;
2957 raw_spin_lock_irq(&ctx->lock);
2958 if (event->state >= PERF_EVENT_STATE_INACTIVE ||
2959 event->state < PERF_EVENT_STATE_ERROR) {
2961 raw_spin_unlock_irq(&ctx->lock);
2966 * If the event is in error state, clear that first.
2968 * That way, if we see the event in error state below, we know that it
2969 * has gone back into error state, as distinct from the task having
2970 * been scheduled away before the cross-call arrived.
2972 if (event->state == PERF_EVENT_STATE_ERROR) {
2974 * Detached SIBLING events cannot leave ERROR state.
2976 if (event->event_caps & PERF_EV_CAP_SIBLING &&
2977 event->group_leader == event)
2980 event->state = PERF_EVENT_STATE_OFF;
2982 raw_spin_unlock_irq(&ctx->lock);
2984 event_function_call(event, __perf_event_enable, NULL);
2988 * See perf_event_disable();
2990 void perf_event_enable(struct perf_event *event)
2992 struct perf_event_context *ctx;
2994 ctx = perf_event_ctx_lock(event);
2995 _perf_event_enable(event);
2996 perf_event_ctx_unlock(event, ctx);
2998 EXPORT_SYMBOL_GPL(perf_event_enable);
3000 struct stop_event_data {
3001 struct perf_event *event;
3002 unsigned int restart;
3005 static int __perf_event_stop(void *info)
3007 struct stop_event_data *sd = info;
3008 struct perf_event *event = sd->event;
3010 /* if it's already INACTIVE, do nothing */
3011 if (READ_ONCE(event->state) != PERF_EVENT_STATE_ACTIVE)
3014 /* matches smp_wmb() in event_sched_in() */
3018 * There is a window with interrupts enabled before we get here,
3019 * so we need to check again lest we try to stop another CPU's event.
3021 if (READ_ONCE(event->oncpu) != smp_processor_id())
3024 event->pmu->stop(event, PERF_EF_UPDATE);
3027 * May race with the actual stop (through perf_pmu_output_stop()),
3028 * but it is only used for events with AUX ring buffer, and such
3029 * events will refuse to restart because of rb::aux_mmap_count==0,
3030 * see comments in perf_aux_output_begin().
3032 * Since this is happening on an event-local CPU, no trace is lost
3036 event->pmu->start(event, 0);
3041 static int perf_event_stop(struct perf_event *event, int restart)
3043 struct stop_event_data sd = {
3050 if (READ_ONCE(event->state) != PERF_EVENT_STATE_ACTIVE)
3053 /* matches smp_wmb() in event_sched_in() */
3057 * We only want to restart ACTIVE events, so if the event goes
3058 * inactive here (event->oncpu==-1), there's nothing more to do;
3059 * fall through with ret==-ENXIO.
3061 ret = cpu_function_call(READ_ONCE(event->oncpu),
3062 __perf_event_stop, &sd);
3063 } while (ret == -EAGAIN);
3069 * In order to contain the amount of racy and tricky in the address filter
3070 * configuration management, it is a two part process:
3072 * (p1) when userspace mappings change as a result of (1) or (2) or (3) below,
3073 * we update the addresses of corresponding vmas in
3074 * event::addr_filter_ranges array and bump the event::addr_filters_gen;
3075 * (p2) when an event is scheduled in (pmu::add), it calls
3076 * perf_event_addr_filters_sync() which calls pmu::addr_filters_sync()
3077 * if the generation has changed since the previous call.
3079 * If (p1) happens while the event is active, we restart it to force (p2).
3081 * (1) perf_addr_filters_apply(): adjusting filters' offsets based on
3082 * pre-existing mappings, called once when new filters arrive via SET_FILTER
3084 * (2) perf_addr_filters_adjust(): adjusting filters' offsets based on newly
3085 * registered mapping, called for every new mmap(), with mm::mmap_lock down
3087 * (3) perf_event_addr_filters_exec(): clearing filters' offsets in the process
3090 void perf_event_addr_filters_sync(struct perf_event *event)
3092 struct perf_addr_filters_head *ifh = perf_event_addr_filters(event);
3094 if (!has_addr_filter(event))
3097 raw_spin_lock(&ifh->lock);
3098 if (event->addr_filters_gen != event->hw.addr_filters_gen) {
3099 event->pmu->addr_filters_sync(event);
3100 event->hw.addr_filters_gen = event->addr_filters_gen;
3102 raw_spin_unlock(&ifh->lock);
3104 EXPORT_SYMBOL_GPL(perf_event_addr_filters_sync);
3106 static int _perf_event_refresh(struct perf_event *event, int refresh)
3109 * not supported on inherited events
3111 if (event->attr.inherit || !is_sampling_event(event))
3114 atomic_add(refresh, &event->event_limit);
3115 _perf_event_enable(event);
3121 * See perf_event_disable()
3123 int perf_event_refresh(struct perf_event *event, int refresh)
3125 struct perf_event_context *ctx;
3128 ctx = perf_event_ctx_lock(event);
3129 ret = _perf_event_refresh(event, refresh);
3130 perf_event_ctx_unlock(event, ctx);
3134 EXPORT_SYMBOL_GPL(perf_event_refresh);
3136 static int perf_event_modify_breakpoint(struct perf_event *bp,
3137 struct perf_event_attr *attr)
3141 _perf_event_disable(bp);
3143 err = modify_user_hw_breakpoint_check(bp, attr, true);
3145 if (!bp->attr.disabled)
3146 _perf_event_enable(bp);
3152 * Copy event-type-independent attributes that may be modified.
3154 static void perf_event_modify_copy_attr(struct perf_event_attr *to,
3155 const struct perf_event_attr *from)
3157 to->sig_data = from->sig_data;
3160 static int perf_event_modify_attr(struct perf_event *event,
3161 struct perf_event_attr *attr)
3163 int (*func)(struct perf_event *, struct perf_event_attr *);
3164 struct perf_event *child;
3167 if (event->attr.type != attr->type)
3170 switch (event->attr.type) {
3171 case PERF_TYPE_BREAKPOINT:
3172 func = perf_event_modify_breakpoint;
3175 /* Place holder for future additions. */
3179 WARN_ON_ONCE(event->ctx->parent_ctx);
3181 mutex_lock(&event->child_mutex);
3183 * Event-type-independent attributes must be copied before event-type
3184 * modification, which will validate that final attributes match the
3185 * source attributes after all relevant attributes have been copied.
3187 perf_event_modify_copy_attr(&event->attr, attr);
3188 err = func(event, attr);
3191 list_for_each_entry(child, &event->child_list, child_list) {
3192 perf_event_modify_copy_attr(&child->attr, attr);
3193 err = func(child, attr);
3198 mutex_unlock(&event->child_mutex);
3202 static void ctx_sched_out(struct perf_event_context *ctx,
3203 struct perf_cpu_context *cpuctx,
3204 enum event_type_t event_type)
3206 struct perf_event *event, *tmp;
3207 int is_active = ctx->is_active;
3209 lockdep_assert_held(&ctx->lock);
3211 if (likely(!ctx->nr_events)) {
3213 * See __perf_remove_from_context().
3215 WARN_ON_ONCE(ctx->is_active);
3217 WARN_ON_ONCE(cpuctx->task_ctx);
3222 * Always update time if it was set; not only when it changes.
3223 * Otherwise we can 'forget' to update time for any but the last
3224 * context we sched out. For example:
3226 * ctx_sched_out(.event_type = EVENT_FLEXIBLE)
3227 * ctx_sched_out(.event_type = EVENT_PINNED)
3229 * would only update time for the pinned events.
3231 if (is_active & EVENT_TIME) {
3232 /* update (and stop) ctx time */
3233 update_context_time(ctx);
3234 update_cgrp_time_from_cpuctx(cpuctx, ctx == &cpuctx->ctx);
3236 * CPU-release for the below ->is_active store,
3237 * see __load_acquire() in perf_event_time_now()
3242 ctx->is_active &= ~event_type;
3243 if (!(ctx->is_active & EVENT_ALL))
3247 WARN_ON_ONCE(cpuctx->task_ctx != ctx);
3248 if (!ctx->is_active)
3249 cpuctx->task_ctx = NULL;
3252 is_active ^= ctx->is_active; /* changed bits */
3254 if (!ctx->nr_active || !(is_active & EVENT_ALL))
3257 perf_pmu_disable(ctx->pmu);
3258 if (is_active & EVENT_PINNED) {
3259 list_for_each_entry_safe(event, tmp, &ctx->pinned_active, active_list)
3260 group_sched_out(event, cpuctx, ctx);
3263 if (is_active & EVENT_FLEXIBLE) {
3264 list_for_each_entry_safe(event, tmp, &ctx->flexible_active, active_list)
3265 group_sched_out(event, cpuctx, ctx);
3268 * Since we cleared EVENT_FLEXIBLE, also clear
3269 * rotate_necessary, is will be reset by
3270 * ctx_flexible_sched_in() when needed.
3272 ctx->rotate_necessary = 0;
3274 perf_pmu_enable(ctx->pmu);
3278 * Test whether two contexts are equivalent, i.e. whether they have both been
3279 * cloned from the same version of the same context.
3281 * Equivalence is measured using a generation number in the context that is
3282 * incremented on each modification to it; see unclone_ctx(), list_add_event()
3283 * and list_del_event().
3285 static int context_equiv(struct perf_event_context *ctx1,
3286 struct perf_event_context *ctx2)
3288 lockdep_assert_held(&ctx1->lock);
3289 lockdep_assert_held(&ctx2->lock);
3291 /* Pinning disables the swap optimization */
3292 if (ctx1->pin_count || ctx2->pin_count)
3295 /* If ctx1 is the parent of ctx2 */
3296 if (ctx1 == ctx2->parent_ctx && ctx1->generation == ctx2->parent_gen)
3299 /* If ctx2 is the parent of ctx1 */
3300 if (ctx1->parent_ctx == ctx2 && ctx1->parent_gen == ctx2->generation)
3304 * If ctx1 and ctx2 have the same parent; we flatten the parent
3305 * hierarchy, see perf_event_init_context().
3307 if (ctx1->parent_ctx && ctx1->parent_ctx == ctx2->parent_ctx &&
3308 ctx1->parent_gen == ctx2->parent_gen)
3315 static void __perf_event_sync_stat(struct perf_event *event,
3316 struct perf_event *next_event)
3320 if (!event->attr.inherit_stat)
3324 * Update the event value, we cannot use perf_event_read()
3325 * because we're in the middle of a context switch and have IRQs
3326 * disabled, which upsets smp_call_function_single(), however
3327 * we know the event must be on the current CPU, therefore we
3328 * don't need to use it.
3330 if (event->state == PERF_EVENT_STATE_ACTIVE)
3331 event->pmu->read(event);
3333 perf_event_update_time(event);
3336 * In order to keep per-task stats reliable we need to flip the event
3337 * values when we flip the contexts.
3339 value = local64_read(&next_event->count);
3340 value = local64_xchg(&event->count, value);
3341 local64_set(&next_event->count, value);
3343 swap(event->total_time_enabled, next_event->total_time_enabled);
3344 swap(event->total_time_running, next_event->total_time_running);
3347 * Since we swizzled the values, update the user visible data too.
3349 perf_event_update_userpage(event);
3350 perf_event_update_userpage(next_event);
3353 static void perf_event_sync_stat(struct perf_event_context *ctx,
3354 struct perf_event_context *next_ctx)
3356 struct perf_event *event, *next_event;
3361 update_context_time(ctx);
3363 event = list_first_entry(&ctx->event_list,
3364 struct perf_event, event_entry);
3366 next_event = list_first_entry(&next_ctx->event_list,
3367 struct perf_event, event_entry);
3369 while (&event->event_entry != &ctx->event_list &&
3370 &next_event->event_entry != &next_ctx->event_list) {
3372 __perf_event_sync_stat(event, next_event);
3374 event = list_next_entry(event, event_entry);
3375 next_event = list_next_entry(next_event, event_entry);
3379 static void perf_event_context_sched_out(struct task_struct *task, int ctxn,
3380 struct task_struct *next)
3382 struct perf_event_context *ctx = task->perf_event_ctxp[ctxn];
3383 struct perf_event_context *next_ctx;
3384 struct perf_event_context *parent, *next_parent;
3385 struct perf_cpu_context *cpuctx;
3393 cpuctx = __get_cpu_context(ctx);
3394 if (!cpuctx->task_ctx)
3398 next_ctx = next->perf_event_ctxp[ctxn];
3402 parent = rcu_dereference(ctx->parent_ctx);
3403 next_parent = rcu_dereference(next_ctx->parent_ctx);
3405 /* If neither context have a parent context; they cannot be clones. */
3406 if (!parent && !next_parent)
3409 if (next_parent == ctx || next_ctx == parent || next_parent == parent) {
3411 * Looks like the two contexts are clones, so we might be
3412 * able to optimize the context switch. We lock both
3413 * contexts and check that they are clones under the
3414 * lock (including re-checking that neither has been
3415 * uncloned in the meantime). It doesn't matter which
3416 * order we take the locks because no other cpu could
3417 * be trying to lock both of these tasks.
3419 raw_spin_lock(&ctx->lock);
3420 raw_spin_lock_nested(&next_ctx->lock, SINGLE_DEPTH_NESTING);
3421 if (context_equiv(ctx, next_ctx)) {
3423 WRITE_ONCE(ctx->task, next);
3424 WRITE_ONCE(next_ctx->task, task);
3426 perf_pmu_disable(pmu);
3428 if (cpuctx->sched_cb_usage && pmu->sched_task)
3429 pmu->sched_task(ctx, false);
3432 * PMU specific parts of task perf context can require
3433 * additional synchronization. As an example of such
3434 * synchronization see implementation details of Intel
3435 * LBR call stack data profiling;
3437 if (pmu->swap_task_ctx)
3438 pmu->swap_task_ctx(ctx, next_ctx);
3440 swap(ctx->task_ctx_data, next_ctx->task_ctx_data);
3442 perf_pmu_enable(pmu);
3445 * RCU_INIT_POINTER here is safe because we've not
3446 * modified the ctx and the above modification of
3447 * ctx->task and ctx->task_ctx_data are immaterial
3448 * since those values are always verified under
3449 * ctx->lock which we're now holding.
3451 RCU_INIT_POINTER(task->perf_event_ctxp[ctxn], next_ctx);
3452 RCU_INIT_POINTER(next->perf_event_ctxp[ctxn], ctx);
3456 perf_event_sync_stat(ctx, next_ctx);
3458 raw_spin_unlock(&next_ctx->lock);
3459 raw_spin_unlock(&ctx->lock);
3465 raw_spin_lock(&ctx->lock);
3466 perf_pmu_disable(pmu);
3468 if (cpuctx->sched_cb_usage && pmu->sched_task)
3469 pmu->sched_task(ctx, false);
3470 task_ctx_sched_out(cpuctx, ctx, EVENT_ALL);
3472 perf_pmu_enable(pmu);
3473 raw_spin_unlock(&ctx->lock);
3477 static DEFINE_PER_CPU(struct list_head, sched_cb_list);
3479 void perf_sched_cb_dec(struct pmu *pmu)
3481 struct perf_cpu_context *cpuctx = this_cpu_ptr(pmu->pmu_cpu_context);
3483 this_cpu_dec(perf_sched_cb_usages);
3485 if (!--cpuctx->sched_cb_usage)
3486 list_del(&cpuctx->sched_cb_entry);
3490 void perf_sched_cb_inc(struct pmu *pmu)
3492 struct perf_cpu_context *cpuctx = this_cpu_ptr(pmu->pmu_cpu_context);
3494 if (!cpuctx->sched_cb_usage++)
3495 list_add(&cpuctx->sched_cb_entry, this_cpu_ptr(&sched_cb_list));
3497 this_cpu_inc(perf_sched_cb_usages);
3501 * This function provides the context switch callback to the lower code
3502 * layer. It is invoked ONLY when the context switch callback is enabled.
3504 * This callback is relevant even to per-cpu events; for example multi event
3505 * PEBS requires this to provide PID/TID information. This requires we flush
3506 * all queued PEBS records before we context switch to a new task.
3508 static void __perf_pmu_sched_task(struct perf_cpu_context *cpuctx, bool sched_in)
3512 pmu = cpuctx->ctx.pmu; /* software PMUs will not have sched_task */
3514 if (WARN_ON_ONCE(!pmu->sched_task))
3517 perf_ctx_lock(cpuctx, cpuctx->task_ctx);
3518 perf_pmu_disable(pmu);
3520 pmu->sched_task(cpuctx->task_ctx, sched_in);
3522 perf_pmu_enable(pmu);
3523 perf_ctx_unlock(cpuctx, cpuctx->task_ctx);
3526 static void perf_pmu_sched_task(struct task_struct *prev,
3527 struct task_struct *next,
3530 struct perf_cpu_context *cpuctx;
3535 list_for_each_entry(cpuctx, this_cpu_ptr(&sched_cb_list), sched_cb_entry) {
3536 /* will be handled in perf_event_context_sched_in/out */
3537 if (cpuctx->task_ctx)
3540 __perf_pmu_sched_task(cpuctx, sched_in);
3544 static void perf_event_switch(struct task_struct *task,
3545 struct task_struct *next_prev, bool sched_in);
3547 #define for_each_task_context_nr(ctxn) \
3548 for ((ctxn) = 0; (ctxn) < perf_nr_task_contexts; (ctxn)++)
3551 * Called from scheduler to remove the events of the current task,
3552 * with interrupts disabled.
3554 * We stop each event and update the event value in event->count.
3556 * This does not protect us against NMI, but disable()
3557 * sets the disabled bit in the control field of event _before_
3558 * accessing the event control register. If a NMI hits, then it will
3559 * not restart the event.
3561 void __perf_event_task_sched_out(struct task_struct *task,
3562 struct task_struct *next)
3566 if (__this_cpu_read(perf_sched_cb_usages))
3567 perf_pmu_sched_task(task, next, false);
3569 if (atomic_read(&nr_switch_events))
3570 perf_event_switch(task, next, false);
3572 for_each_task_context_nr(ctxn)
3573 perf_event_context_sched_out(task, ctxn, next);
3576 * if cgroup events exist on this CPU, then we need
3577 * to check if we have to switch out PMU state.
3578 * cgroup event are system-wide mode only
3580 if (atomic_read(this_cpu_ptr(&perf_cgroup_events)))
3581 perf_cgroup_switch(next);
3585 * Called with IRQs disabled
3587 static void cpu_ctx_sched_out(struct perf_cpu_context *cpuctx,
3588 enum event_type_t event_type)
3590 ctx_sched_out(&cpuctx->ctx, cpuctx, event_type);
3593 static bool perf_less_group_idx(const void *l, const void *r)
3595 const struct perf_event *le = *(const struct perf_event **)l;
3596 const struct perf_event *re = *(const struct perf_event **)r;
3598 return le->group_index < re->group_index;
3601 static void swap_ptr(void *l, void *r)
3603 void **lp = l, **rp = r;
3608 static const struct min_heap_callbacks perf_min_heap = {
3609 .elem_size = sizeof(struct perf_event *),
3610 .less = perf_less_group_idx,
3614 static void __heap_add(struct min_heap *heap, struct perf_event *event)
3616 struct perf_event **itrs = heap->data;
3619 itrs[heap->nr] = event;
3624 static noinline int visit_groups_merge(struct perf_cpu_context *cpuctx,
3625 struct perf_event_groups *groups, int cpu,
3626 int (*func)(struct perf_event *, void *),
3629 #ifdef CONFIG_CGROUP_PERF
3630 struct cgroup_subsys_state *css = NULL;
3632 /* Space for per CPU and/or any CPU event iterators. */
3633 struct perf_event *itrs[2];
3634 struct min_heap event_heap;
3635 struct perf_event **evt;
3639 event_heap = (struct min_heap){
3640 .data = cpuctx->heap,
3642 .size = cpuctx->heap_size,
3645 lockdep_assert_held(&cpuctx->ctx.lock);
3647 #ifdef CONFIG_CGROUP_PERF
3649 css = &cpuctx->cgrp->css;
3652 event_heap = (struct min_heap){
3655 .size = ARRAY_SIZE(itrs),
3657 /* Events not within a CPU context may be on any CPU. */
3658 __heap_add(&event_heap, perf_event_groups_first(groups, -1, NULL));
3660 evt = event_heap.data;
3662 __heap_add(&event_heap, perf_event_groups_first(groups, cpu, NULL));
3664 #ifdef CONFIG_CGROUP_PERF
3665 for (; css; css = css->parent)
3666 __heap_add(&event_heap, perf_event_groups_first(groups, cpu, css->cgroup));
3669 min_heapify_all(&event_heap, &perf_min_heap);
3671 while (event_heap.nr) {
3672 ret = func(*evt, data);
3676 *evt = perf_event_groups_next(*evt);
3678 min_heapify(&event_heap, 0, &perf_min_heap);
3680 min_heap_pop(&event_heap, &perf_min_heap);
3687 * Because the userpage is strictly per-event (there is no concept of context,
3688 * so there cannot be a context indirection), every userpage must be updated
3689 * when context time starts :-(
3691 * IOW, we must not miss EVENT_TIME edges.
3693 static inline bool event_update_userpage(struct perf_event *event)
3695 if (likely(!atomic_read(&event->mmap_count)))
3698 perf_event_update_time(event);
3699 perf_event_update_userpage(event);
3704 static inline void group_update_userpage(struct perf_event *group_event)
3706 struct perf_event *event;
3708 if (!event_update_userpage(group_event))
3711 for_each_sibling_event(event, group_event)
3712 event_update_userpage(event);
3715 static int merge_sched_in(struct perf_event *event, void *data)
3717 struct perf_event_context *ctx = event->ctx;
3718 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
3719 int *can_add_hw = data;
3721 if (event->state <= PERF_EVENT_STATE_OFF)
3724 if (!event_filter_match(event))
3727 if (group_can_go_on(event, cpuctx, *can_add_hw)) {
3728 if (!group_sched_in(event, cpuctx, ctx))
3729 list_add_tail(&event->active_list, get_event_list(event));
3732 if (event->state == PERF_EVENT_STATE_INACTIVE) {
3734 if (event->attr.pinned) {
3735 perf_cgroup_event_disable(event, ctx);
3736 perf_event_set_state(event, PERF_EVENT_STATE_ERROR);
3738 ctx->rotate_necessary = 1;
3739 perf_mux_hrtimer_restart(cpuctx);
3740 group_update_userpage(event);
3748 ctx_pinned_sched_in(struct perf_event_context *ctx,
3749 struct perf_cpu_context *cpuctx)
3753 if (ctx != &cpuctx->ctx)
3756 visit_groups_merge(cpuctx, &ctx->pinned_groups,
3758 merge_sched_in, &can_add_hw);
3762 ctx_flexible_sched_in(struct perf_event_context *ctx,
3763 struct perf_cpu_context *cpuctx)
3767 if (ctx != &cpuctx->ctx)
3770 visit_groups_merge(cpuctx, &ctx->flexible_groups,
3772 merge_sched_in, &can_add_hw);
3776 ctx_sched_in(struct perf_event_context *ctx,
3777 struct perf_cpu_context *cpuctx,
3778 enum event_type_t event_type)
3780 int is_active = ctx->is_active;
3782 lockdep_assert_held(&ctx->lock);
3784 if (likely(!ctx->nr_events))
3787 if (is_active ^ EVENT_TIME) {
3788 /* start ctx time */
3789 __update_context_time(ctx, false);
3790 perf_cgroup_set_timestamp(cpuctx);
3792 * CPU-release for the below ->is_active store,
3793 * see __load_acquire() in perf_event_time_now()
3798 ctx->is_active |= (event_type | EVENT_TIME);
3801 cpuctx->task_ctx = ctx;
3803 WARN_ON_ONCE(cpuctx->task_ctx != ctx);
3806 is_active ^= ctx->is_active; /* changed bits */
3809 * First go through the list and put on any pinned groups
3810 * in order to give them the best chance of going on.
3812 if (is_active & EVENT_PINNED)
3813 ctx_pinned_sched_in(ctx, cpuctx);
3815 /* Then walk through the lower prio flexible groups */
3816 if (is_active & EVENT_FLEXIBLE)
3817 ctx_flexible_sched_in(ctx, cpuctx);
3820 static void cpu_ctx_sched_in(struct perf_cpu_context *cpuctx,
3821 enum event_type_t event_type)
3823 struct perf_event_context *ctx = &cpuctx->ctx;
3825 ctx_sched_in(ctx, cpuctx, event_type);
3828 static void perf_event_context_sched_in(struct perf_event_context *ctx,
3829 struct task_struct *task)
3831 struct perf_cpu_context *cpuctx;
3834 cpuctx = __get_cpu_context(ctx);
3837 * HACK: for HETEROGENEOUS the task context might have switched to a
3838 * different PMU, force (re)set the context,
3840 pmu = ctx->pmu = cpuctx->ctx.pmu;
3842 if (cpuctx->task_ctx == ctx) {
3843 if (cpuctx->sched_cb_usage)
3844 __perf_pmu_sched_task(cpuctx, true);
3848 perf_ctx_lock(cpuctx, ctx);
3850 * We must check ctx->nr_events while holding ctx->lock, such
3851 * that we serialize against perf_install_in_context().
3853 if (!ctx->nr_events)
3856 perf_pmu_disable(pmu);
3858 * We want to keep the following priority order:
3859 * cpu pinned (that don't need to move), task pinned,
3860 * cpu flexible, task flexible.
3862 * However, if task's ctx is not carrying any pinned
3863 * events, no need to flip the cpuctx's events around.
3865 if (!RB_EMPTY_ROOT(&ctx->pinned_groups.tree))
3866 cpu_ctx_sched_out(cpuctx, EVENT_FLEXIBLE);
3867 perf_event_sched_in(cpuctx, ctx);
3869 if (cpuctx->sched_cb_usage && pmu->sched_task)
3870 pmu->sched_task(cpuctx->task_ctx, true);
3872 perf_pmu_enable(pmu);
3875 perf_ctx_unlock(cpuctx, ctx);
3879 * Called from scheduler to add the events of the current task
3880 * with interrupts disabled.
3882 * We restore the event value and then enable it.
3884 * This does not protect us against NMI, but enable()
3885 * sets the enabled bit in the control field of event _before_
3886 * accessing the event control register. If a NMI hits, then it will
3887 * keep the event running.
3889 void __perf_event_task_sched_in(struct task_struct *prev,
3890 struct task_struct *task)
3892 struct perf_event_context *ctx;
3895 for_each_task_context_nr(ctxn) {
3896 ctx = task->perf_event_ctxp[ctxn];
3900 perf_event_context_sched_in(ctx, task);
3903 if (atomic_read(&nr_switch_events))
3904 perf_event_switch(task, prev, true);
3906 if (__this_cpu_read(perf_sched_cb_usages))
3907 perf_pmu_sched_task(prev, task, true);
3910 static u64 perf_calculate_period(struct perf_event *event, u64 nsec, u64 count)
3912 u64 frequency = event->attr.sample_freq;
3913 u64 sec = NSEC_PER_SEC;
3914 u64 divisor, dividend;
3916 int count_fls, nsec_fls, frequency_fls, sec_fls;
3918 count_fls = fls64(count);
3919 nsec_fls = fls64(nsec);
3920 frequency_fls = fls64(frequency);
3924 * We got @count in @nsec, with a target of sample_freq HZ
3925 * the target period becomes:
3928 * period = -------------------
3929 * @nsec * sample_freq
3934 * Reduce accuracy by one bit such that @a and @b converge
3935 * to a similar magnitude.
3937 #define REDUCE_FLS(a, b) \
3939 if (a##_fls > b##_fls) { \
3949 * Reduce accuracy until either term fits in a u64, then proceed with
3950 * the other, so that finally we can do a u64/u64 division.
3952 while (count_fls + sec_fls > 64 && nsec_fls + frequency_fls > 64) {
3953 REDUCE_FLS(nsec, frequency);
3954 REDUCE_FLS(sec, count);
3957 if (count_fls + sec_fls > 64) {
3958 divisor = nsec * frequency;
3960 while (count_fls + sec_fls > 64) {
3961 REDUCE_FLS(count, sec);
3965 dividend = count * sec;
3967 dividend = count * sec;
3969 while (nsec_fls + frequency_fls > 64) {
3970 REDUCE_FLS(nsec, frequency);
3974 divisor = nsec * frequency;
3980 return div64_u64(dividend, divisor);
3983 static DEFINE_PER_CPU(int, perf_throttled_count);
3984 static DEFINE_PER_CPU(u64, perf_throttled_seq);
3986 static void perf_adjust_period(struct perf_event *event, u64 nsec, u64 count, bool disable)
3988 struct hw_perf_event *hwc = &event->hw;
3989 s64 period, sample_period;
3992 period = perf_calculate_period(event, nsec, count);
3994 delta = (s64)(period - hwc->sample_period);
3995 delta = (delta + 7) / 8; /* low pass filter */
3997 sample_period = hwc->sample_period + delta;
4002 hwc->sample_period = sample_period;
4004 if (local64_read(&hwc->period_left) > 8*sample_period) {
4006 event->pmu->stop(event, PERF_EF_UPDATE);
4008 local64_set(&hwc->period_left, 0);
4011 event->pmu->start(event, PERF_EF_RELOAD);
4016 * combine freq adjustment with unthrottling to avoid two passes over the
4017 * events. At the same time, make sure, having freq events does not change
4018 * the rate of unthrottling as that would introduce bias.
4020 static void perf_adjust_freq_unthr_context(struct perf_event_context *ctx,
4023 struct perf_event *event;
4024 struct hw_perf_event *hwc;
4025 u64 now, period = TICK_NSEC;
4029 * only need to iterate over all events iff:
4030 * - context have events in frequency mode (needs freq adjust)
4031 * - there are events to unthrottle on this cpu
4033 if (!(ctx->nr_freq || needs_unthr))
4036 raw_spin_lock(&ctx->lock);
4037 perf_pmu_disable(ctx->pmu);
4039 list_for_each_entry_rcu(event, &ctx->event_list, event_entry) {
4040 if (event->state != PERF_EVENT_STATE_ACTIVE)
4043 if (!event_filter_match(event))
4046 perf_pmu_disable(event->pmu);
4050 if (hwc->interrupts == MAX_INTERRUPTS) {
4051 hwc->interrupts = 0;
4052 perf_log_throttle(event, 1);
4053 event->pmu->start(event, 0);
4056 if (!event->attr.freq || !event->attr.sample_freq)
4060 * stop the event and update event->count
4062 event->pmu->stop(event, PERF_EF_UPDATE);
4064 now = local64_read(&event->count);
4065 delta = now - hwc->freq_count_stamp;
4066 hwc->freq_count_stamp = now;
4070 * reload only if value has changed
4071 * we have stopped the event so tell that
4072 * to perf_adjust_period() to avoid stopping it
4076 perf_adjust_period(event, period, delta, false);
4078 event->pmu->start(event, delta > 0 ? PERF_EF_RELOAD : 0);
4080 perf_pmu_enable(event->pmu);
4083 perf_pmu_enable(ctx->pmu);
4084 raw_spin_unlock(&ctx->lock);
4088 * Move @event to the tail of the @ctx's elegible events.
4090 static void rotate_ctx(struct perf_event_context *ctx, struct perf_event *event)
4093 * Rotate the first entry last of non-pinned groups. Rotation might be
4094 * disabled by the inheritance code.
4096 if (ctx->rotate_disable)
4099 perf_event_groups_delete(&ctx->flexible_groups, event);
4100 perf_event_groups_insert(&ctx->flexible_groups, event);
4103 /* pick an event from the flexible_groups to rotate */
4104 static inline struct perf_event *
4105 ctx_event_to_rotate(struct perf_event_context *ctx)
4107 struct perf_event *event;
4109 /* pick the first active flexible event */
4110 event = list_first_entry_or_null(&ctx->flexible_active,
4111 struct perf_event, active_list);
4113 /* if no active flexible event, pick the first event */
4115 event = rb_entry_safe(rb_first(&ctx->flexible_groups.tree),
4116 typeof(*event), group_node);
4120 * Unconditionally clear rotate_necessary; if ctx_flexible_sched_in()
4121 * finds there are unschedulable events, it will set it again.
4123 ctx->rotate_necessary = 0;
4128 static bool perf_rotate_context(struct perf_cpu_context *cpuctx)
4130 struct perf_event *cpu_event = NULL, *task_event = NULL;
4131 struct perf_event_context *task_ctx = NULL;
4132 int cpu_rotate, task_rotate;
4135 * Since we run this from IRQ context, nobody can install new
4136 * events, thus the event count values are stable.
4139 cpu_rotate = cpuctx->ctx.rotate_necessary;
4140 task_ctx = cpuctx->task_ctx;
4141 task_rotate = task_ctx ? task_ctx->rotate_necessary : 0;
4143 if (!(cpu_rotate || task_rotate))
4146 perf_ctx_lock(cpuctx, cpuctx->task_ctx);
4147 perf_pmu_disable(cpuctx->ctx.pmu);
4150 task_event = ctx_event_to_rotate(task_ctx);
4152 cpu_event = ctx_event_to_rotate(&cpuctx->ctx);
4155 * As per the order given at ctx_resched() first 'pop' task flexible
4156 * and then, if needed CPU flexible.
4158 if (task_event || (task_ctx && cpu_event))
4159 ctx_sched_out(task_ctx, cpuctx, EVENT_FLEXIBLE);
4161 cpu_ctx_sched_out(cpuctx, EVENT_FLEXIBLE);
4164 rotate_ctx(task_ctx, task_event);
4166 rotate_ctx(&cpuctx->ctx, cpu_event);
4168 perf_event_sched_in(cpuctx, task_ctx);
4170 perf_pmu_enable(cpuctx->ctx.pmu);
4171 perf_ctx_unlock(cpuctx, cpuctx->task_ctx);
4176 void perf_event_task_tick(void)
4178 struct list_head *head = this_cpu_ptr(&active_ctx_list);
4179 struct perf_event_context *ctx, *tmp;
4182 lockdep_assert_irqs_disabled();
4184 __this_cpu_inc(perf_throttled_seq);
4185 throttled = __this_cpu_xchg(perf_throttled_count, 0);
4186 tick_dep_clear_cpu(smp_processor_id(), TICK_DEP_BIT_PERF_EVENTS);
4188 list_for_each_entry_safe(ctx, tmp, head, active_ctx_list)
4189 perf_adjust_freq_unthr_context(ctx, throttled);
4192 static int event_enable_on_exec(struct perf_event *event,
4193 struct perf_event_context *ctx)
4195 if (!event->attr.enable_on_exec)
4198 event->attr.enable_on_exec = 0;
4199 if (event->state >= PERF_EVENT_STATE_INACTIVE)
4202 perf_event_set_state(event, PERF_EVENT_STATE_INACTIVE);
4208 * Enable all of a task's events that have been marked enable-on-exec.
4209 * This expects task == current.
4211 static void perf_event_enable_on_exec(int ctxn)
4213 struct perf_event_context *ctx, *clone_ctx = NULL;
4214 enum event_type_t event_type = 0;
4215 struct perf_cpu_context *cpuctx;
4216 struct perf_event *event;
4217 unsigned long flags;
4220 local_irq_save(flags);
4221 ctx = current->perf_event_ctxp[ctxn];
4222 if (!ctx || !ctx->nr_events)
4225 cpuctx = __get_cpu_context(ctx);
4226 perf_ctx_lock(cpuctx, ctx);
4227 ctx_sched_out(ctx, cpuctx, EVENT_TIME);
4228 list_for_each_entry(event, &ctx->event_list, event_entry) {
4229 enabled |= event_enable_on_exec(event, ctx);
4230 event_type |= get_event_type(event);
4234 * Unclone and reschedule this context if we enabled any event.
4237 clone_ctx = unclone_ctx(ctx);
4238 ctx_resched(cpuctx, ctx, event_type);
4240 ctx_sched_in(ctx, cpuctx, EVENT_TIME);
4242 perf_ctx_unlock(cpuctx, ctx);
4245 local_irq_restore(flags);
4251 static void perf_remove_from_owner(struct perf_event *event);
4252 static void perf_event_exit_event(struct perf_event *event,
4253 struct perf_event_context *ctx);
4256 * Removes all events from the current task that have been marked
4257 * remove-on-exec, and feeds their values back to parent events.
4259 static void perf_event_remove_on_exec(int ctxn)
4261 struct perf_event_context *ctx, *clone_ctx = NULL;
4262 struct perf_event *event, *next;
4263 unsigned long flags;
4264 bool modified = false;
4266 ctx = perf_pin_task_context(current, ctxn);
4270 mutex_lock(&ctx->mutex);
4272 if (WARN_ON_ONCE(ctx->task != current))
4275 list_for_each_entry_safe(event, next, &ctx->event_list, event_entry) {
4276 if (!event->attr.remove_on_exec)
4279 if (!is_kernel_event(event))
4280 perf_remove_from_owner(event);
4284 perf_event_exit_event(event, ctx);
4287 raw_spin_lock_irqsave(&ctx->lock, flags);
4289 clone_ctx = unclone_ctx(ctx);
4291 raw_spin_unlock_irqrestore(&ctx->lock, flags);
4294 mutex_unlock(&ctx->mutex);
4301 struct perf_read_data {
4302 struct perf_event *event;
4307 static int __perf_event_read_cpu(struct perf_event *event, int event_cpu)
4309 u16 local_pkg, event_pkg;
4311 if (event->group_caps & PERF_EV_CAP_READ_ACTIVE_PKG) {
4312 int local_cpu = smp_processor_id();
4314 event_pkg = topology_physical_package_id(event_cpu);
4315 local_pkg = topology_physical_package_id(local_cpu);
4317 if (event_pkg == local_pkg)
4325 * Cross CPU call to read the hardware event
4327 static void __perf_event_read(void *info)
4329 struct perf_read_data *data = info;
4330 struct perf_event *sub, *event = data->event;
4331 struct perf_event_context *ctx = event->ctx;
4332 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
4333 struct pmu *pmu = event->pmu;
4336 * If this is a task context, we need to check whether it is
4337 * the current task context of this cpu. If not it has been
4338 * scheduled out before the smp call arrived. In that case
4339 * event->count would have been updated to a recent sample
4340 * when the event was scheduled out.
4342 if (ctx->task && cpuctx->task_ctx != ctx)
4345 raw_spin_lock(&ctx->lock);
4346 if (ctx->is_active & EVENT_TIME) {
4347 update_context_time(ctx);
4348 update_cgrp_time_from_event(event);
4351 perf_event_update_time(event);
4353 perf_event_update_sibling_time(event);
4355 if (event->state != PERF_EVENT_STATE_ACTIVE)
4364 pmu->start_txn(pmu, PERF_PMU_TXN_READ);
4368 for_each_sibling_event(sub, event) {
4369 if (sub->state == PERF_EVENT_STATE_ACTIVE) {
4371 * Use sibling's PMU rather than @event's since
4372 * sibling could be on different (eg: software) PMU.
4374 sub->pmu->read(sub);
4378 data->ret = pmu->commit_txn(pmu);
4381 raw_spin_unlock(&ctx->lock);
4384 static inline u64 perf_event_count(struct perf_event *event)
4386 return local64_read(&event->count) + atomic64_read(&event->child_count);
4389 static void calc_timer_values(struct perf_event *event,
4396 *now = perf_clock();
4397 ctx_time = perf_event_time_now(event, *now);
4398 __perf_update_times(event, ctx_time, enabled, running);
4402 * NMI-safe method to read a local event, that is an event that
4404 * - either for the current task, or for this CPU
4405 * - does not have inherit set, for inherited task events
4406 * will not be local and we cannot read them atomically
4407 * - must not have a pmu::count method
4409 int perf_event_read_local(struct perf_event *event, u64 *value,
4410 u64 *enabled, u64 *running)
4412 unsigned long flags;
4416 * Disabling interrupts avoids all counter scheduling (context
4417 * switches, timer based rotation and IPIs).
4419 local_irq_save(flags);
4422 * It must not be an event with inherit set, we cannot read
4423 * all child counters from atomic context.
4425 if (event->attr.inherit) {
4430 /* If this is a per-task event, it must be for current */
4431 if ((event->attach_state & PERF_ATTACH_TASK) &&
4432 event->hw.target != current) {
4437 /* If this is a per-CPU event, it must be for this CPU */
4438 if (!(event->attach_state & PERF_ATTACH_TASK) &&
4439 event->cpu != smp_processor_id()) {
4444 /* If this is a pinned event it must be running on this CPU */
4445 if (event->attr.pinned && event->oncpu != smp_processor_id()) {
4451 * If the event is currently on this CPU, its either a per-task event,
4452 * or local to this CPU. Furthermore it means its ACTIVE (otherwise
4455 if (event->oncpu == smp_processor_id())
4456 event->pmu->read(event);
4458 *value = local64_read(&event->count);
4459 if (enabled || running) {
4460 u64 __enabled, __running, __now;;
4462 calc_timer_values(event, &__now, &__enabled, &__running);
4464 *enabled = __enabled;
4466 *running = __running;
4469 local_irq_restore(flags);
4474 static int perf_event_read(struct perf_event *event, bool group)
4476 enum perf_event_state state = READ_ONCE(event->state);
4477 int event_cpu, ret = 0;
4480 * If event is enabled and currently active on a CPU, update the
4481 * value in the event structure:
4484 if (state == PERF_EVENT_STATE_ACTIVE) {
4485 struct perf_read_data data;
4488 * Orders the ->state and ->oncpu loads such that if we see
4489 * ACTIVE we must also see the right ->oncpu.
4491 * Matches the smp_wmb() from event_sched_in().
4495 event_cpu = READ_ONCE(event->oncpu);
4496 if ((unsigned)event_cpu >= nr_cpu_ids)
4499 data = (struct perf_read_data){
4506 event_cpu = __perf_event_read_cpu(event, event_cpu);
4509 * Purposely ignore the smp_call_function_single() return
4512 * If event_cpu isn't a valid CPU it means the event got
4513 * scheduled out and that will have updated the event count.
4515 * Therefore, either way, we'll have an up-to-date event count
4518 (void)smp_call_function_single(event_cpu, __perf_event_read, &data, 1);
4522 } else if (state == PERF_EVENT_STATE_INACTIVE) {
4523 struct perf_event_context *ctx = event->ctx;
4524 unsigned long flags;
4526 raw_spin_lock_irqsave(&ctx->lock, flags);
4527 state = event->state;
4528 if (state != PERF_EVENT_STATE_INACTIVE) {
4529 raw_spin_unlock_irqrestore(&ctx->lock, flags);
4534 * May read while context is not active (e.g., thread is
4535 * blocked), in that case we cannot update context time
4537 if (ctx->is_active & EVENT_TIME) {
4538 update_context_time(ctx);
4539 update_cgrp_time_from_event(event);
4542 perf_event_update_time(event);
4544 perf_event_update_sibling_time(event);
4545 raw_spin_unlock_irqrestore(&ctx->lock, flags);
4552 * Initialize the perf_event context in a task_struct:
4554 static void __perf_event_init_context(struct perf_event_context *ctx)
4556 raw_spin_lock_init(&ctx->lock);
4557 mutex_init(&ctx->mutex);
4558 INIT_LIST_HEAD(&ctx->active_ctx_list);
4559 perf_event_groups_init(&ctx->pinned_groups);
4560 perf_event_groups_init(&ctx->flexible_groups);
4561 INIT_LIST_HEAD(&ctx->event_list);
4562 INIT_LIST_HEAD(&ctx->pinned_active);
4563 INIT_LIST_HEAD(&ctx->flexible_active);
4564 refcount_set(&ctx->refcount, 1);
4567 static struct perf_event_context *
4568 alloc_perf_context(struct pmu *pmu, struct task_struct *task)
4570 struct perf_event_context *ctx;
4572 ctx = kzalloc(sizeof(struct perf_event_context), GFP_KERNEL);
4576 __perf_event_init_context(ctx);
4578 ctx->task = get_task_struct(task);
4584 static struct task_struct *
4585 find_lively_task_by_vpid(pid_t vpid)
4587 struct task_struct *task;
4593 task = find_task_by_vpid(vpid);
4595 get_task_struct(task);
4599 return ERR_PTR(-ESRCH);
4605 * Returns a matching context with refcount and pincount.
4607 static struct perf_event_context *
4608 find_get_context(struct pmu *pmu, struct task_struct *task,
4609 struct perf_event *event)
4611 struct perf_event_context *ctx, *clone_ctx = NULL;
4612 struct perf_cpu_context *cpuctx;
4613 void *task_ctx_data = NULL;
4614 unsigned long flags;
4616 int cpu = event->cpu;
4619 /* Must be root to operate on a CPU event: */
4620 err = perf_allow_cpu(&event->attr);
4622 return ERR_PTR(err);
4624 cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
4627 raw_spin_lock_irqsave(&ctx->lock, flags);
4629 raw_spin_unlock_irqrestore(&ctx->lock, flags);
4635 ctxn = pmu->task_ctx_nr;
4639 if (event->attach_state & PERF_ATTACH_TASK_DATA) {
4640 task_ctx_data = alloc_task_ctx_data(pmu);
4641 if (!task_ctx_data) {
4648 ctx = perf_lock_task_context(task, ctxn, &flags);
4650 clone_ctx = unclone_ctx(ctx);
4653 if (task_ctx_data && !ctx->task_ctx_data) {
4654 ctx->task_ctx_data = task_ctx_data;
4655 task_ctx_data = NULL;
4657 raw_spin_unlock_irqrestore(&ctx->lock, flags);
4662 ctx = alloc_perf_context(pmu, task);
4667 if (task_ctx_data) {
4668 ctx->task_ctx_data = task_ctx_data;
4669 task_ctx_data = NULL;
4673 mutex_lock(&task->perf_event_mutex);
4675 * If it has already passed perf_event_exit_task().
4676 * we must see PF_EXITING, it takes this mutex too.
4678 if (task->flags & PF_EXITING)
4680 else if (task->perf_event_ctxp[ctxn])
4685 rcu_assign_pointer(task->perf_event_ctxp[ctxn], ctx);
4687 mutex_unlock(&task->perf_event_mutex);
4689 if (unlikely(err)) {
4698 free_task_ctx_data(pmu, task_ctx_data);
4702 free_task_ctx_data(pmu, task_ctx_data);
4703 return ERR_PTR(err);
4706 static void perf_event_free_filter(struct perf_event *event);
4708 static void free_event_rcu(struct rcu_head *head)
4710 struct perf_event *event;
4712 event = container_of(head, struct perf_event, rcu_head);
4714 put_pid_ns(event->ns);
4715 perf_event_free_filter(event);
4716 kmem_cache_free(perf_event_cache, event);
4719 static void ring_buffer_attach(struct perf_event *event,
4720 struct perf_buffer *rb);
4722 static void detach_sb_event(struct perf_event *event)
4724 struct pmu_event_list *pel = per_cpu_ptr(&pmu_sb_events, event->cpu);
4726 raw_spin_lock(&pel->lock);
4727 list_del_rcu(&event->sb_list);
4728 raw_spin_unlock(&pel->lock);
4731 static bool is_sb_event(struct perf_event *event)
4733 struct perf_event_attr *attr = &event->attr;
4738 if (event->attach_state & PERF_ATTACH_TASK)
4741 if (attr->mmap || attr->mmap_data || attr->mmap2 ||
4742 attr->comm || attr->comm_exec ||
4743 attr->task || attr->ksymbol ||
4744 attr->context_switch || attr->text_poke ||
4750 static void unaccount_pmu_sb_event(struct perf_event *event)
4752 if (is_sb_event(event))
4753 detach_sb_event(event);
4756 static void unaccount_event_cpu(struct perf_event *event, int cpu)
4761 if (is_cgroup_event(event))
4762 atomic_dec(&per_cpu(perf_cgroup_events, cpu));
4765 #ifdef CONFIG_NO_HZ_FULL
4766 static DEFINE_SPINLOCK(nr_freq_lock);
4769 static void unaccount_freq_event_nohz(void)
4771 #ifdef CONFIG_NO_HZ_FULL
4772 spin_lock(&nr_freq_lock);
4773 if (atomic_dec_and_test(&nr_freq_events))
4774 tick_nohz_dep_clear(TICK_DEP_BIT_PERF_EVENTS);
4775 spin_unlock(&nr_freq_lock);
4779 static void unaccount_freq_event(void)
4781 if (tick_nohz_full_enabled())
4782 unaccount_freq_event_nohz();
4784 atomic_dec(&nr_freq_events);
4787 static void unaccount_event(struct perf_event *event)
4794 if (event->attach_state & (PERF_ATTACH_TASK | PERF_ATTACH_SCHED_CB))
4796 if (event->attr.mmap || event->attr.mmap_data)
4797 atomic_dec(&nr_mmap_events);
4798 if (event->attr.build_id)
4799 atomic_dec(&nr_build_id_events);
4800 if (event->attr.comm)
4801 atomic_dec(&nr_comm_events);
4802 if (event->attr.namespaces)
4803 atomic_dec(&nr_namespaces_events);
4804 if (event->attr.cgroup)
4805 atomic_dec(&nr_cgroup_events);
4806 if (event->attr.task)
4807 atomic_dec(&nr_task_events);
4808 if (event->attr.freq)
4809 unaccount_freq_event();
4810 if (event->attr.context_switch) {
4812 atomic_dec(&nr_switch_events);
4814 if (is_cgroup_event(event))
4816 if (has_branch_stack(event))
4818 if (event->attr.ksymbol)
4819 atomic_dec(&nr_ksymbol_events);
4820 if (event->attr.bpf_event)
4821 atomic_dec(&nr_bpf_events);
4822 if (event->attr.text_poke)
4823 atomic_dec(&nr_text_poke_events);
4826 if (!atomic_add_unless(&perf_sched_count, -1, 1))
4827 schedule_delayed_work(&perf_sched_work, HZ);
4830 unaccount_event_cpu(event, event->cpu);
4832 unaccount_pmu_sb_event(event);
4835 static void perf_sched_delayed(struct work_struct *work)
4837 mutex_lock(&perf_sched_mutex);
4838 if (atomic_dec_and_test(&perf_sched_count))
4839 static_branch_disable(&perf_sched_events);
4840 mutex_unlock(&perf_sched_mutex);
4844 * The following implement mutual exclusion of events on "exclusive" pmus
4845 * (PERF_PMU_CAP_EXCLUSIVE). Such pmus can only have one event scheduled
4846 * at a time, so we disallow creating events that might conflict, namely:
4848 * 1) cpu-wide events in the presence of per-task events,
4849 * 2) per-task events in the presence of cpu-wide events,
4850 * 3) two matching events on the same context.
4852 * The former two cases are handled in the allocation path (perf_event_alloc(),
4853 * _free_event()), the latter -- before the first perf_install_in_context().
4855 static int exclusive_event_init(struct perf_event *event)
4857 struct pmu *pmu = event->pmu;
4859 if (!is_exclusive_pmu(pmu))
4863 * Prevent co-existence of per-task and cpu-wide events on the
4864 * same exclusive pmu.
4866 * Negative pmu::exclusive_cnt means there are cpu-wide
4867 * events on this "exclusive" pmu, positive means there are
4870 * Since this is called in perf_event_alloc() path, event::ctx
4871 * doesn't exist yet; it is, however, safe to use PERF_ATTACH_TASK
4872 * to mean "per-task event", because unlike other attach states it
4873 * never gets cleared.
4875 if (event->attach_state & PERF_ATTACH_TASK) {
4876 if (!atomic_inc_unless_negative(&pmu->exclusive_cnt))
4879 if (!atomic_dec_unless_positive(&pmu->exclusive_cnt))
4886 static void exclusive_event_destroy(struct perf_event *event)
4888 struct pmu *pmu = event->pmu;
4890 if (!is_exclusive_pmu(pmu))
4893 /* see comment in exclusive_event_init() */
4894 if (event->attach_state & PERF_ATTACH_TASK)
4895 atomic_dec(&pmu->exclusive_cnt);
4897 atomic_inc(&pmu->exclusive_cnt);
4900 static bool exclusive_event_match(struct perf_event *e1, struct perf_event *e2)
4902 if ((e1->pmu == e2->pmu) &&
4903 (e1->cpu == e2->cpu ||
4910 static bool exclusive_event_installable(struct perf_event *event,
4911 struct perf_event_context *ctx)
4913 struct perf_event *iter_event;
4914 struct pmu *pmu = event->pmu;
4916 lockdep_assert_held(&ctx->mutex);
4918 if (!is_exclusive_pmu(pmu))
4921 list_for_each_entry(iter_event, &ctx->event_list, event_entry) {
4922 if (exclusive_event_match(iter_event, event))
4929 static void perf_addr_filters_splice(struct perf_event *event,
4930 struct list_head *head);
4932 static void _free_event(struct perf_event *event)
4934 irq_work_sync(&event->pending);
4936 unaccount_event(event);
4938 security_perf_event_free(event);
4942 * Can happen when we close an event with re-directed output.
4944 * Since we have a 0 refcount, perf_mmap_close() will skip
4945 * over us; possibly making our ring_buffer_put() the last.
4947 mutex_lock(&event->mmap_mutex);
4948 ring_buffer_attach(event, NULL);
4949 mutex_unlock(&event->mmap_mutex);
4952 if (is_cgroup_event(event))
4953 perf_detach_cgroup(event);
4955 if (!event->parent) {
4956 if (event->attr.sample_type & PERF_SAMPLE_CALLCHAIN)
4957 put_callchain_buffers();
4960 perf_event_free_bpf_prog(event);
4961 perf_addr_filters_splice(event, NULL);
4962 kfree(event->addr_filter_ranges);
4965 event->destroy(event);
4968 * Must be after ->destroy(), due to uprobe_perf_close() using
4971 if (event->hw.target)
4972 put_task_struct(event->hw.target);
4975 * perf_event_free_task() relies on put_ctx() being 'last', in particular
4976 * all task references must be cleaned up.
4979 put_ctx(event->ctx);
4981 exclusive_event_destroy(event);
4982 module_put(event->pmu->module);
4984 call_rcu(&event->rcu_head, free_event_rcu);
4988 * Used to free events which have a known refcount of 1, such as in error paths
4989 * where the event isn't exposed yet and inherited events.
4991 static void free_event(struct perf_event *event)
4993 if (WARN(atomic_long_cmpxchg(&event->refcount, 1, 0) != 1,
4994 "unexpected event refcount: %ld; ptr=%p\n",
4995 atomic_long_read(&event->refcount), event)) {
4996 /* leak to avoid use-after-free */
5004 * Remove user event from the owner task.
5006 static void perf_remove_from_owner(struct perf_event *event)
5008 struct task_struct *owner;
5012 * Matches the smp_store_release() in perf_event_exit_task(). If we
5013 * observe !owner it means the list deletion is complete and we can
5014 * indeed free this event, otherwise we need to serialize on
5015 * owner->perf_event_mutex.
5017 owner = READ_ONCE(event->owner);
5020 * Since delayed_put_task_struct() also drops the last
5021 * task reference we can safely take a new reference
5022 * while holding the rcu_read_lock().
5024 get_task_struct(owner);
5030 * If we're here through perf_event_exit_task() we're already
5031 * holding ctx->mutex which would be an inversion wrt. the
5032 * normal lock order.
5034 * However we can safely take this lock because its the child
5037 mutex_lock_nested(&owner->perf_event_mutex, SINGLE_DEPTH_NESTING);
5040 * We have to re-check the event->owner field, if it is cleared
5041 * we raced with perf_event_exit_task(), acquiring the mutex
5042 * ensured they're done, and we can proceed with freeing the
5046 list_del_init(&event->owner_entry);
5047 smp_store_release(&event->owner, NULL);
5049 mutex_unlock(&owner->perf_event_mutex);
5050 put_task_struct(owner);
5054 static void put_event(struct perf_event *event)
5056 if (!atomic_long_dec_and_test(&event->refcount))
5063 * Kill an event dead; while event:refcount will preserve the event
5064 * object, it will not preserve its functionality. Once the last 'user'
5065 * gives up the object, we'll destroy the thing.
5067 int perf_event_release_kernel(struct perf_event *event)
5069 struct perf_event_context *ctx = event->ctx;
5070 struct perf_event *child, *tmp;
5071 LIST_HEAD(free_list);
5074 * If we got here through err_file: fput(event_file); we will not have
5075 * attached to a context yet.
5078 WARN_ON_ONCE(event->attach_state &
5079 (PERF_ATTACH_CONTEXT|PERF_ATTACH_GROUP));
5083 if (!is_kernel_event(event))
5084 perf_remove_from_owner(event);
5086 ctx = perf_event_ctx_lock(event);
5087 WARN_ON_ONCE(ctx->parent_ctx);
5088 perf_remove_from_context(event, DETACH_GROUP);
5090 raw_spin_lock_irq(&ctx->lock);
5092 * Mark this event as STATE_DEAD, there is no external reference to it
5095 * Anybody acquiring event->child_mutex after the below loop _must_
5096 * also see this, most importantly inherit_event() which will avoid
5097 * placing more children on the list.
5099 * Thus this guarantees that we will in fact observe and kill _ALL_
5102 event->state = PERF_EVENT_STATE_DEAD;
5103 raw_spin_unlock_irq(&ctx->lock);
5105 perf_event_ctx_unlock(event, ctx);
5108 mutex_lock(&event->child_mutex);
5109 list_for_each_entry(child, &event->child_list, child_list) {
5112 * Cannot change, child events are not migrated, see the
5113 * comment with perf_event_ctx_lock_nested().
5115 ctx = READ_ONCE(child->ctx);
5117 * Since child_mutex nests inside ctx::mutex, we must jump
5118 * through hoops. We start by grabbing a reference on the ctx.
5120 * Since the event cannot get freed while we hold the
5121 * child_mutex, the context must also exist and have a !0
5127 * Now that we have a ctx ref, we can drop child_mutex, and
5128 * acquire ctx::mutex without fear of it going away. Then we
5129 * can re-acquire child_mutex.
5131 mutex_unlock(&event->child_mutex);
5132 mutex_lock(&ctx->mutex);
5133 mutex_lock(&event->child_mutex);
5136 * Now that we hold ctx::mutex and child_mutex, revalidate our
5137 * state, if child is still the first entry, it didn't get freed
5138 * and we can continue doing so.
5140 tmp = list_first_entry_or_null(&event->child_list,
5141 struct perf_event, child_list);
5143 perf_remove_from_context(child, DETACH_GROUP);
5144 list_move(&child->child_list, &free_list);
5146 * This matches the refcount bump in inherit_event();
5147 * this can't be the last reference.
5152 mutex_unlock(&event->child_mutex);
5153 mutex_unlock(&ctx->mutex);
5157 mutex_unlock(&event->child_mutex);
5159 list_for_each_entry_safe(child, tmp, &free_list, child_list) {
5160 void *var = &child->ctx->refcount;
5162 list_del(&child->child_list);
5166 * Wake any perf_event_free_task() waiting for this event to be
5169 smp_mb(); /* pairs with wait_var_event() */
5174 put_event(event); /* Must be the 'last' reference */
5177 EXPORT_SYMBOL_GPL(perf_event_release_kernel);
5180 * Called when the last reference to the file is gone.
5182 static int perf_release(struct inode *inode, struct file *file)
5184 perf_event_release_kernel(file->private_data);
5188 static u64 __perf_event_read_value(struct perf_event *event, u64 *enabled, u64 *running)
5190 struct perf_event *child;
5196 mutex_lock(&event->child_mutex);
5198 (void)perf_event_read(event, false);
5199 total += perf_event_count(event);
5201 *enabled += event->total_time_enabled +
5202 atomic64_read(&event->child_total_time_enabled);
5203 *running += event->total_time_running +
5204 atomic64_read(&event->child_total_time_running);
5206 list_for_each_entry(child, &event->child_list, child_list) {
5207 (void)perf_event_read(child, false);
5208 total += perf_event_count(child);
5209 *enabled += child->total_time_enabled;
5210 *running += child->total_time_running;
5212 mutex_unlock(&event->child_mutex);
5217 u64 perf_event_read_value(struct perf_event *event, u64 *enabled, u64 *running)
5219 struct perf_event_context *ctx;
5222 ctx = perf_event_ctx_lock(event);
5223 count = __perf_event_read_value(event, enabled, running);
5224 perf_event_ctx_unlock(event, ctx);
5228 EXPORT_SYMBOL_GPL(perf_event_read_value);
5230 static int __perf_read_group_add(struct perf_event *leader,
5231 u64 read_format, u64 *values)
5233 struct perf_event_context *ctx = leader->ctx;
5234 struct perf_event *sub;
5235 unsigned long flags;
5236 int n = 1; /* skip @nr */
5239 ret = perf_event_read(leader, true);
5243 raw_spin_lock_irqsave(&ctx->lock, flags);
5246 * Since we co-schedule groups, {enabled,running} times of siblings
5247 * will be identical to those of the leader, so we only publish one
5250 if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED) {
5251 values[n++] += leader->total_time_enabled +
5252 atomic64_read(&leader->child_total_time_enabled);
5255 if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING) {
5256 values[n++] += leader->total_time_running +
5257 atomic64_read(&leader->child_total_time_running);
5261 * Write {count,id} tuples for every sibling.
5263 values[n++] += perf_event_count(leader);
5264 if (read_format & PERF_FORMAT_ID)
5265 values[n++] = primary_event_id(leader);
5266 if (read_format & PERF_FORMAT_LOST)
5267 values[n++] = atomic64_read(&leader->lost_samples);
5269 for_each_sibling_event(sub, leader) {
5270 values[n++] += perf_event_count(sub);
5271 if (read_format & PERF_FORMAT_ID)
5272 values[n++] = primary_event_id(sub);
5273 if (read_format & PERF_FORMAT_LOST)
5274 values[n++] = atomic64_read(&sub->lost_samples);
5277 raw_spin_unlock_irqrestore(&ctx->lock, flags);
5281 static int perf_read_group(struct perf_event *event,
5282 u64 read_format, char __user *buf)
5284 struct perf_event *leader = event->group_leader, *child;
5285 struct perf_event_context *ctx = leader->ctx;
5289 lockdep_assert_held(&ctx->mutex);
5291 values = kzalloc(event->read_size, GFP_KERNEL);
5295 values[0] = 1 + leader->nr_siblings;
5298 * By locking the child_mutex of the leader we effectively
5299 * lock the child list of all siblings.. XXX explain how.
5301 mutex_lock(&leader->child_mutex);
5303 ret = __perf_read_group_add(leader, read_format, values);
5307 list_for_each_entry(child, &leader->child_list, child_list) {
5308 ret = __perf_read_group_add(child, read_format, values);
5313 mutex_unlock(&leader->child_mutex);
5315 ret = event->read_size;
5316 if (copy_to_user(buf, values, event->read_size))
5321 mutex_unlock(&leader->child_mutex);
5327 static int perf_read_one(struct perf_event *event,
5328 u64 read_format, char __user *buf)
5330 u64 enabled, running;
5334 values[n++] = __perf_event_read_value(event, &enabled, &running);
5335 if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED)
5336 values[n++] = enabled;
5337 if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING)
5338 values[n++] = running;
5339 if (read_format & PERF_FORMAT_ID)
5340 values[n++] = primary_event_id(event);
5341 if (read_format & PERF_FORMAT_LOST)
5342 values[n++] = atomic64_read(&event->lost_samples);
5344 if (copy_to_user(buf, values, n * sizeof(u64)))
5347 return n * sizeof(u64);
5350 static bool is_event_hup(struct perf_event *event)
5354 if (event->state > PERF_EVENT_STATE_EXIT)
5357 mutex_lock(&event->child_mutex);
5358 no_children = list_empty(&event->child_list);
5359 mutex_unlock(&event->child_mutex);
5364 * Read the performance event - simple non blocking version for now
5367 __perf_read(struct perf_event *event, char __user *buf, size_t count)
5369 u64 read_format = event->attr.read_format;
5373 * Return end-of-file for a read on an event that is in
5374 * error state (i.e. because it was pinned but it couldn't be
5375 * scheduled on to the CPU at some point).
5377 if (event->state == PERF_EVENT_STATE_ERROR)
5380 if (count < event->read_size)
5383 WARN_ON_ONCE(event->ctx->parent_ctx);
5384 if (read_format & PERF_FORMAT_GROUP)
5385 ret = perf_read_group(event, read_format, buf);
5387 ret = perf_read_one(event, read_format, buf);
5393 perf_read(struct file *file, char __user *buf, size_t count, loff_t *ppos)
5395 struct perf_event *event = file->private_data;
5396 struct perf_event_context *ctx;
5399 ret = security_perf_event_read(event);
5403 ctx = perf_event_ctx_lock(event);
5404 ret = __perf_read(event, buf, count);
5405 perf_event_ctx_unlock(event, ctx);
5410 static __poll_t perf_poll(struct file *file, poll_table *wait)
5412 struct perf_event *event = file->private_data;
5413 struct perf_buffer *rb;
5414 __poll_t events = EPOLLHUP;
5416 poll_wait(file, &event->waitq, wait);
5418 if (is_event_hup(event))
5422 * Pin the event->rb by taking event->mmap_mutex; otherwise
5423 * perf_event_set_output() can swizzle our rb and make us miss wakeups.
5425 mutex_lock(&event->mmap_mutex);
5428 events = atomic_xchg(&rb->poll, 0);
5429 mutex_unlock(&event->mmap_mutex);
5433 static void _perf_event_reset(struct perf_event *event)
5435 (void)perf_event_read(event, false);
5436 local64_set(&event->count, 0);
5437 perf_event_update_userpage(event);
5440 /* Assume it's not an event with inherit set. */
5441 u64 perf_event_pause(struct perf_event *event, bool reset)
5443 struct perf_event_context *ctx;
5446 ctx = perf_event_ctx_lock(event);
5447 WARN_ON_ONCE(event->attr.inherit);
5448 _perf_event_disable(event);
5449 count = local64_read(&event->count);
5451 local64_set(&event->count, 0);
5452 perf_event_ctx_unlock(event, ctx);
5456 EXPORT_SYMBOL_GPL(perf_event_pause);
5459 * Holding the top-level event's child_mutex means that any
5460 * descendant process that has inherited this event will block
5461 * in perf_event_exit_event() if it goes to exit, thus satisfying the
5462 * task existence requirements of perf_event_enable/disable.
5464 static void perf_event_for_each_child(struct perf_event *event,
5465 void (*func)(struct perf_event *))
5467 struct perf_event *child;
5469 WARN_ON_ONCE(event->ctx->parent_ctx);
5471 mutex_lock(&event->child_mutex);
5473 list_for_each_entry(child, &event->child_list, child_list)
5475 mutex_unlock(&event->child_mutex);
5478 static void perf_event_for_each(struct perf_event *event,
5479 void (*func)(struct perf_event *))
5481 struct perf_event_context *ctx = event->ctx;
5482 struct perf_event *sibling;
5484 lockdep_assert_held(&ctx->mutex);
5486 event = event->group_leader;
5488 perf_event_for_each_child(event, func);
5489 for_each_sibling_event(sibling, event)
5490 perf_event_for_each_child(sibling, func);
5493 static void __perf_event_period(struct perf_event *event,
5494 struct perf_cpu_context *cpuctx,
5495 struct perf_event_context *ctx,
5498 u64 value = *((u64 *)info);
5501 if (event->attr.freq) {
5502 event->attr.sample_freq = value;
5504 event->attr.sample_period = value;
5505 event->hw.sample_period = value;
5508 active = (event->state == PERF_EVENT_STATE_ACTIVE);
5510 perf_pmu_disable(ctx->pmu);
5512 * We could be throttled; unthrottle now to avoid the tick
5513 * trying to unthrottle while we already re-started the event.
5515 if (event->hw.interrupts == MAX_INTERRUPTS) {
5516 event->hw.interrupts = 0;
5517 perf_log_throttle(event, 1);
5519 event->pmu->stop(event, PERF_EF_UPDATE);
5522 local64_set(&event->hw.period_left, 0);
5525 event->pmu->start(event, PERF_EF_RELOAD);
5526 perf_pmu_enable(ctx->pmu);
5530 static int perf_event_check_period(struct perf_event *event, u64 value)
5532 return event->pmu->check_period(event, value);
5535 static int _perf_event_period(struct perf_event *event, u64 value)
5537 if (!is_sampling_event(event))
5543 if (event->attr.freq && value > sysctl_perf_event_sample_rate)
5546 if (perf_event_check_period(event, value))
5549 if (!event->attr.freq && (value & (1ULL << 63)))
5552 event_function_call(event, __perf_event_period, &value);
5557 int perf_event_period(struct perf_event *event, u64 value)
5559 struct perf_event_context *ctx;
5562 ctx = perf_event_ctx_lock(event);
5563 ret = _perf_event_period(event, value);
5564 perf_event_ctx_unlock(event, ctx);
5568 EXPORT_SYMBOL_GPL(perf_event_period);
5570 static const struct file_operations perf_fops;
5572 static inline int perf_fget_light(int fd, struct fd *p)
5574 struct fd f = fdget(fd);
5578 if (f.file->f_op != &perf_fops) {
5586 static int perf_event_set_output(struct perf_event *event,
5587 struct perf_event *output_event);
5588 static int perf_event_set_filter(struct perf_event *event, void __user *arg);
5589 static int perf_copy_attr(struct perf_event_attr __user *uattr,
5590 struct perf_event_attr *attr);
5592 static long _perf_ioctl(struct perf_event *event, unsigned int cmd, unsigned long arg)
5594 void (*func)(struct perf_event *);
5598 case PERF_EVENT_IOC_ENABLE:
5599 func = _perf_event_enable;
5601 case PERF_EVENT_IOC_DISABLE:
5602 func = _perf_event_disable;
5604 case PERF_EVENT_IOC_RESET:
5605 func = _perf_event_reset;
5608 case PERF_EVENT_IOC_REFRESH:
5609 return _perf_event_refresh(event, arg);
5611 case PERF_EVENT_IOC_PERIOD:
5615 if (copy_from_user(&value, (u64 __user *)arg, sizeof(value)))
5618 return _perf_event_period(event, value);
5620 case PERF_EVENT_IOC_ID:
5622 u64 id = primary_event_id(event);
5624 if (copy_to_user((void __user *)arg, &id, sizeof(id)))
5629 case PERF_EVENT_IOC_SET_OUTPUT:
5633 struct perf_event *output_event;
5635 ret = perf_fget_light(arg, &output);
5638 output_event = output.file->private_data;
5639 ret = perf_event_set_output(event, output_event);
5642 ret = perf_event_set_output(event, NULL);
5647 case PERF_EVENT_IOC_SET_FILTER:
5648 return perf_event_set_filter(event, (void __user *)arg);
5650 case PERF_EVENT_IOC_SET_BPF:
5652 struct bpf_prog *prog;
5655 prog = bpf_prog_get(arg);
5657 return PTR_ERR(prog);
5659 err = perf_event_set_bpf_prog(event, prog, 0);
5668 case PERF_EVENT_IOC_PAUSE_OUTPUT: {
5669 struct perf_buffer *rb;
5672 rb = rcu_dereference(event->rb);
5673 if (!rb || !rb->nr_pages) {
5677 rb_toggle_paused(rb, !!arg);
5682 case PERF_EVENT_IOC_QUERY_BPF:
5683 return perf_event_query_prog_array(event, (void __user *)arg);
5685 case PERF_EVENT_IOC_MODIFY_ATTRIBUTES: {
5686 struct perf_event_attr new_attr;
5687 int err = perf_copy_attr((struct perf_event_attr __user *)arg,
5693 return perf_event_modify_attr(event, &new_attr);
5699 if (flags & PERF_IOC_FLAG_GROUP)
5700 perf_event_for_each(event, func);
5702 perf_event_for_each_child(event, func);
5707 static long perf_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
5709 struct perf_event *event = file->private_data;
5710 struct perf_event_context *ctx;
5713 /* Treat ioctl like writes as it is likely a mutating operation. */
5714 ret = security_perf_event_write(event);
5718 ctx = perf_event_ctx_lock(event);
5719 ret = _perf_ioctl(event, cmd, arg);
5720 perf_event_ctx_unlock(event, ctx);
5725 #ifdef CONFIG_COMPAT
5726 static long perf_compat_ioctl(struct file *file, unsigned int cmd,
5729 switch (_IOC_NR(cmd)) {
5730 case _IOC_NR(PERF_EVENT_IOC_SET_FILTER):
5731 case _IOC_NR(PERF_EVENT_IOC_ID):
5732 case _IOC_NR(PERF_EVENT_IOC_QUERY_BPF):
5733 case _IOC_NR(PERF_EVENT_IOC_MODIFY_ATTRIBUTES):
5734 /* Fix up pointer size (usually 4 -> 8 in 32-on-64-bit case */
5735 if (_IOC_SIZE(cmd) == sizeof(compat_uptr_t)) {
5736 cmd &= ~IOCSIZE_MASK;
5737 cmd |= sizeof(void *) << IOCSIZE_SHIFT;
5741 return perf_ioctl(file, cmd, arg);
5744 # define perf_compat_ioctl NULL
5747 int perf_event_task_enable(void)
5749 struct perf_event_context *ctx;
5750 struct perf_event *event;
5752 mutex_lock(¤t->perf_event_mutex);
5753 list_for_each_entry(event, ¤t->perf_event_list, owner_entry) {
5754 ctx = perf_event_ctx_lock(event);
5755 perf_event_for_each_child(event, _perf_event_enable);
5756 perf_event_ctx_unlock(event, ctx);
5758 mutex_unlock(¤t->perf_event_mutex);
5763 int perf_event_task_disable(void)
5765 struct perf_event_context *ctx;
5766 struct perf_event *event;
5768 mutex_lock(¤t->perf_event_mutex);
5769 list_for_each_entry(event, ¤t->perf_event_list, owner_entry) {
5770 ctx = perf_event_ctx_lock(event);
5771 perf_event_for_each_child(event, _perf_event_disable);
5772 perf_event_ctx_unlock(event, ctx);
5774 mutex_unlock(¤t->perf_event_mutex);
5779 static int perf_event_index(struct perf_event *event)
5781 if (event->hw.state & PERF_HES_STOPPED)
5784 if (event->state != PERF_EVENT_STATE_ACTIVE)
5787 return event->pmu->event_idx(event);
5790 static void perf_event_init_userpage(struct perf_event *event)
5792 struct perf_event_mmap_page *userpg;
5793 struct perf_buffer *rb;
5796 rb = rcu_dereference(event->rb);
5800 userpg = rb->user_page;
5802 /* Allow new userspace to detect that bit 0 is deprecated */
5803 userpg->cap_bit0_is_deprecated = 1;
5804 userpg->size = offsetof(struct perf_event_mmap_page, __reserved);
5805 userpg->data_offset = PAGE_SIZE;
5806 userpg->data_size = perf_data_size(rb);
5812 void __weak arch_perf_update_userpage(
5813 struct perf_event *event, struct perf_event_mmap_page *userpg, u64 now)
5818 * Callers need to ensure there can be no nesting of this function, otherwise
5819 * the seqlock logic goes bad. We can not serialize this because the arch
5820 * code calls this from NMI context.
5822 void perf_event_update_userpage(struct perf_event *event)
5824 struct perf_event_mmap_page *userpg;
5825 struct perf_buffer *rb;
5826 u64 enabled, running, now;
5829 rb = rcu_dereference(event->rb);
5834 * compute total_time_enabled, total_time_running
5835 * based on snapshot values taken when the event
5836 * was last scheduled in.
5838 * we cannot simply called update_context_time()
5839 * because of locking issue as we can be called in
5842 calc_timer_values(event, &now, &enabled, &running);
5844 userpg = rb->user_page;
5846 * Disable preemption to guarantee consistent time stamps are stored to
5852 userpg->index = perf_event_index(event);
5853 userpg->offset = perf_event_count(event);
5855 userpg->offset -= local64_read(&event->hw.prev_count);
5857 userpg->time_enabled = enabled +
5858 atomic64_read(&event->child_total_time_enabled);
5860 userpg->time_running = running +
5861 atomic64_read(&event->child_total_time_running);
5863 arch_perf_update_userpage(event, userpg, now);
5871 EXPORT_SYMBOL_GPL(perf_event_update_userpage);
5873 static vm_fault_t perf_mmap_fault(struct vm_fault *vmf)
5875 struct perf_event *event = vmf->vma->vm_file->private_data;
5876 struct perf_buffer *rb;
5877 vm_fault_t ret = VM_FAULT_SIGBUS;
5879 if (vmf->flags & FAULT_FLAG_MKWRITE) {
5880 if (vmf->pgoff == 0)
5886 rb = rcu_dereference(event->rb);
5890 if (vmf->pgoff && (vmf->flags & FAULT_FLAG_WRITE))
5893 vmf->page = perf_mmap_to_page(rb, vmf->pgoff);
5897 get_page(vmf->page);
5898 vmf->page->mapping = vmf->vma->vm_file->f_mapping;
5899 vmf->page->index = vmf->pgoff;
5908 static void ring_buffer_attach(struct perf_event *event,
5909 struct perf_buffer *rb)
5911 struct perf_buffer *old_rb = NULL;
5912 unsigned long flags;
5914 WARN_ON_ONCE(event->parent);
5918 * Should be impossible, we set this when removing
5919 * event->rb_entry and wait/clear when adding event->rb_entry.
5921 WARN_ON_ONCE(event->rcu_pending);
5924 spin_lock_irqsave(&old_rb->event_lock, flags);
5925 list_del_rcu(&event->rb_entry);
5926 spin_unlock_irqrestore(&old_rb->event_lock, flags);
5928 event->rcu_batches = get_state_synchronize_rcu();
5929 event->rcu_pending = 1;
5933 if (event->rcu_pending) {
5934 cond_synchronize_rcu(event->rcu_batches);
5935 event->rcu_pending = 0;
5938 spin_lock_irqsave(&rb->event_lock, flags);
5939 list_add_rcu(&event->rb_entry, &rb->event_list);
5940 spin_unlock_irqrestore(&rb->event_lock, flags);
5944 * Avoid racing with perf_mmap_close(AUX): stop the event
5945 * before swizzling the event::rb pointer; if it's getting
5946 * unmapped, its aux_mmap_count will be 0 and it won't
5947 * restart. See the comment in __perf_pmu_output_stop().
5949 * Data will inevitably be lost when set_output is done in
5950 * mid-air, but then again, whoever does it like this is
5951 * not in for the data anyway.
5954 perf_event_stop(event, 0);
5956 rcu_assign_pointer(event->rb, rb);
5959 ring_buffer_put(old_rb);
5961 * Since we detached before setting the new rb, so that we
5962 * could attach the new rb, we could have missed a wakeup.
5965 wake_up_all(&event->waitq);
5969 static void ring_buffer_wakeup(struct perf_event *event)
5971 struct perf_buffer *rb;
5974 event = event->parent;
5977 rb = rcu_dereference(event->rb);
5979 list_for_each_entry_rcu(event, &rb->event_list, rb_entry)
5980 wake_up_all(&event->waitq);
5985 struct perf_buffer *ring_buffer_get(struct perf_event *event)
5987 struct perf_buffer *rb;
5990 event = event->parent;
5993 rb = rcu_dereference(event->rb);
5995 if (!refcount_inc_not_zero(&rb->refcount))
6003 void ring_buffer_put(struct perf_buffer *rb)
6005 if (!refcount_dec_and_test(&rb->refcount))
6008 WARN_ON_ONCE(!list_empty(&rb->event_list));
6010 call_rcu(&rb->rcu_head, rb_free_rcu);
6013 static void perf_mmap_open(struct vm_area_struct *vma)
6015 struct perf_event *event = vma->vm_file->private_data;
6017 atomic_inc(&event->mmap_count);
6018 atomic_inc(&event->rb->mmap_count);
6021 atomic_inc(&event->rb->aux_mmap_count);
6023 if (event->pmu->event_mapped)
6024 event->pmu->event_mapped(event, vma->vm_mm);
6027 static void perf_pmu_output_stop(struct perf_event *event);
6030 * A buffer can be mmap()ed multiple times; either directly through the same
6031 * event, or through other events by use of perf_event_set_output().
6033 * In order to undo the VM accounting done by perf_mmap() we need to destroy
6034 * the buffer here, where we still have a VM context. This means we need
6035 * to detach all events redirecting to us.
6037 static void perf_mmap_close(struct vm_area_struct *vma)
6039 struct perf_event *event = vma->vm_file->private_data;
6040 struct perf_buffer *rb = ring_buffer_get(event);
6041 struct user_struct *mmap_user = rb->mmap_user;
6042 int mmap_locked = rb->mmap_locked;
6043 unsigned long size = perf_data_size(rb);
6044 bool detach_rest = false;
6046 if (event->pmu->event_unmapped)
6047 event->pmu->event_unmapped(event, vma->vm_mm);
6050 * rb->aux_mmap_count will always drop before rb->mmap_count and
6051 * event->mmap_count, so it is ok to use event->mmap_mutex to
6052 * serialize with perf_mmap here.
6054 if (rb_has_aux(rb) && vma->vm_pgoff == rb->aux_pgoff &&
6055 atomic_dec_and_mutex_lock(&rb->aux_mmap_count, &event->mmap_mutex)) {
6057 * Stop all AUX events that are writing to this buffer,
6058 * so that we can free its AUX pages and corresponding PMU
6059 * data. Note that after rb::aux_mmap_count dropped to zero,
6060 * they won't start any more (see perf_aux_output_begin()).
6062 perf_pmu_output_stop(event);
6064 /* now it's safe to free the pages */
6065 atomic_long_sub(rb->aux_nr_pages - rb->aux_mmap_locked, &mmap_user->locked_vm);
6066 atomic64_sub(rb->aux_mmap_locked, &vma->vm_mm->pinned_vm);
6068 /* this has to be the last one */
6070 WARN_ON_ONCE(refcount_read(&rb->aux_refcount));
6072 mutex_unlock(&event->mmap_mutex);
6075 if (atomic_dec_and_test(&rb->mmap_count))
6078 if (!atomic_dec_and_mutex_lock(&event->mmap_count, &event->mmap_mutex))
6081 ring_buffer_attach(event, NULL);
6082 mutex_unlock(&event->mmap_mutex);
6084 /* If there's still other mmap()s of this buffer, we're done. */
6089 * No other mmap()s, detach from all other events that might redirect
6090 * into the now unreachable buffer. Somewhat complicated by the
6091 * fact that rb::event_lock otherwise nests inside mmap_mutex.
6095 list_for_each_entry_rcu(event, &rb->event_list, rb_entry) {
6096 if (!atomic_long_inc_not_zero(&event->refcount)) {
6098 * This event is en-route to free_event() which will
6099 * detach it and remove it from the list.
6105 mutex_lock(&event->mmap_mutex);
6107 * Check we didn't race with perf_event_set_output() which can
6108 * swizzle the rb from under us while we were waiting to
6109 * acquire mmap_mutex.
6111 * If we find a different rb; ignore this event, a next
6112 * iteration will no longer find it on the list. We have to
6113 * still restart the iteration to make sure we're not now
6114 * iterating the wrong list.
6116 if (event->rb == rb)
6117 ring_buffer_attach(event, NULL);
6119 mutex_unlock(&event->mmap_mutex);
6123 * Restart the iteration; either we're on the wrong list or
6124 * destroyed its integrity by doing a deletion.
6131 * It could be there's still a few 0-ref events on the list; they'll
6132 * get cleaned up by free_event() -- they'll also still have their
6133 * ref on the rb and will free it whenever they are done with it.
6135 * Aside from that, this buffer is 'fully' detached and unmapped,
6136 * undo the VM accounting.
6139 atomic_long_sub((size >> PAGE_SHIFT) + 1 - mmap_locked,
6140 &mmap_user->locked_vm);
6141 atomic64_sub(mmap_locked, &vma->vm_mm->pinned_vm);
6142 free_uid(mmap_user);
6145 ring_buffer_put(rb); /* could be last */
6148 static const struct vm_operations_struct perf_mmap_vmops = {
6149 .open = perf_mmap_open,
6150 .close = perf_mmap_close, /* non mergeable */
6151 .fault = perf_mmap_fault,
6152 .page_mkwrite = perf_mmap_fault,
6155 static int perf_mmap(struct file *file, struct vm_area_struct *vma)
6157 struct perf_event *event = file->private_data;
6158 unsigned long user_locked, user_lock_limit;
6159 struct user_struct *user = current_user();
6160 struct perf_buffer *rb = NULL;
6161 unsigned long locked, lock_limit;
6162 unsigned long vma_size;
6163 unsigned long nr_pages;
6164 long user_extra = 0, extra = 0;
6165 int ret = 0, flags = 0;
6168 * Don't allow mmap() of inherited per-task counters. This would
6169 * create a performance issue due to all children writing to the
6172 if (event->cpu == -1 && event->attr.inherit)
6175 if (!(vma->vm_flags & VM_SHARED))
6178 ret = security_perf_event_read(event);
6182 vma_size = vma->vm_end - vma->vm_start;
6184 if (vma->vm_pgoff == 0) {
6185 nr_pages = (vma_size / PAGE_SIZE) - 1;
6188 * AUX area mapping: if rb->aux_nr_pages != 0, it's already
6189 * mapped, all subsequent mappings should have the same size
6190 * and offset. Must be above the normal perf buffer.
6192 u64 aux_offset, aux_size;
6197 nr_pages = vma_size / PAGE_SIZE;
6199 mutex_lock(&event->mmap_mutex);
6206 aux_offset = READ_ONCE(rb->user_page->aux_offset);
6207 aux_size = READ_ONCE(rb->user_page->aux_size);
6209 if (aux_offset < perf_data_size(rb) + PAGE_SIZE)
6212 if (aux_offset != vma->vm_pgoff << PAGE_SHIFT)
6215 /* already mapped with a different offset */
6216 if (rb_has_aux(rb) && rb->aux_pgoff != vma->vm_pgoff)
6219 if (aux_size != vma_size || aux_size != nr_pages * PAGE_SIZE)
6222 /* already mapped with a different size */
6223 if (rb_has_aux(rb) && rb->aux_nr_pages != nr_pages)
6226 if (!is_power_of_2(nr_pages))
6229 if (!atomic_inc_not_zero(&rb->mmap_count))
6232 if (rb_has_aux(rb)) {
6233 atomic_inc(&rb->aux_mmap_count);
6238 atomic_set(&rb->aux_mmap_count, 1);
6239 user_extra = nr_pages;
6245 * If we have rb pages ensure they're a power-of-two number, so we
6246 * can do bitmasks instead of modulo.
6248 if (nr_pages != 0 && !is_power_of_2(nr_pages))
6251 if (vma_size != PAGE_SIZE * (1 + nr_pages))
6254 WARN_ON_ONCE(event->ctx->parent_ctx);
6256 mutex_lock(&event->mmap_mutex);
6258 if (data_page_nr(event->rb) != nr_pages) {
6263 if (!atomic_inc_not_zero(&event->rb->mmap_count)) {
6265 * Raced against perf_mmap_close(); remove the
6266 * event and try again.
6268 ring_buffer_attach(event, NULL);
6269 mutex_unlock(&event->mmap_mutex);
6276 user_extra = nr_pages + 1;
6279 user_lock_limit = sysctl_perf_event_mlock >> (PAGE_SHIFT - 10);
6282 * Increase the limit linearly with more CPUs:
6284 user_lock_limit *= num_online_cpus();
6286 user_locked = atomic_long_read(&user->locked_vm);
6289 * sysctl_perf_event_mlock may have changed, so that
6290 * user->locked_vm > user_lock_limit
6292 if (user_locked > user_lock_limit)
6293 user_locked = user_lock_limit;
6294 user_locked += user_extra;
6296 if (user_locked > user_lock_limit) {
6298 * charge locked_vm until it hits user_lock_limit;
6299 * charge the rest from pinned_vm
6301 extra = user_locked - user_lock_limit;
6302 user_extra -= extra;
6305 lock_limit = rlimit(RLIMIT_MEMLOCK);
6306 lock_limit >>= PAGE_SHIFT;
6307 locked = atomic64_read(&vma->vm_mm->pinned_vm) + extra;
6309 if ((locked > lock_limit) && perf_is_paranoid() &&
6310 !capable(CAP_IPC_LOCK)) {
6315 WARN_ON(!rb && event->rb);
6317 if (vma->vm_flags & VM_WRITE)
6318 flags |= RING_BUFFER_WRITABLE;
6321 rb = rb_alloc(nr_pages,
6322 event->attr.watermark ? event->attr.wakeup_watermark : 0,
6330 atomic_set(&rb->mmap_count, 1);
6331 rb->mmap_user = get_current_user();
6332 rb->mmap_locked = extra;
6334 ring_buffer_attach(event, rb);
6336 perf_event_update_time(event);
6337 perf_event_init_userpage(event);
6338 perf_event_update_userpage(event);
6340 ret = rb_alloc_aux(rb, event, vma->vm_pgoff, nr_pages,
6341 event->attr.aux_watermark, flags);
6343 rb->aux_mmap_locked = extra;
6348 atomic_long_add(user_extra, &user->locked_vm);
6349 atomic64_add(extra, &vma->vm_mm->pinned_vm);
6351 atomic_inc(&event->mmap_count);
6353 atomic_dec(&rb->mmap_count);
6356 mutex_unlock(&event->mmap_mutex);
6359 * Since pinned accounting is per vm we cannot allow fork() to copy our
6362 vma->vm_flags |= VM_DONTCOPY | VM_DONTEXPAND | VM_DONTDUMP;
6363 vma->vm_ops = &perf_mmap_vmops;
6365 if (event->pmu->event_mapped)
6366 event->pmu->event_mapped(event, vma->vm_mm);
6371 static int perf_fasync(int fd, struct file *filp, int on)
6373 struct inode *inode = file_inode(filp);
6374 struct perf_event *event = filp->private_data;
6378 retval = fasync_helper(fd, filp, on, &event->fasync);
6379 inode_unlock(inode);
6387 static const struct file_operations perf_fops = {
6388 .llseek = no_llseek,
6389 .release = perf_release,
6392 .unlocked_ioctl = perf_ioctl,
6393 .compat_ioctl = perf_compat_ioctl,
6395 .fasync = perf_fasync,
6401 * If there's data, ensure we set the poll() state and publish everything
6402 * to user-space before waking everybody up.
6405 static inline struct fasync_struct **perf_event_fasync(struct perf_event *event)
6407 /* only the parent has fasync state */
6409 event = event->parent;
6410 return &event->fasync;
6413 void perf_event_wakeup(struct perf_event *event)
6415 ring_buffer_wakeup(event);
6417 if (event->pending_kill) {
6418 kill_fasync(perf_event_fasync(event), SIGIO, event->pending_kill);
6419 event->pending_kill = 0;
6423 static void perf_sigtrap(struct perf_event *event)
6426 * We'd expect this to only occur if the irq_work is delayed and either
6427 * ctx->task or current has changed in the meantime. This can be the
6428 * case on architectures that do not implement arch_irq_work_raise().
6430 if (WARN_ON_ONCE(event->ctx->task != current))
6434 * perf_pending_event() can race with the task exiting.
6436 if (current->flags & PF_EXITING)
6439 send_sig_perf((void __user *)event->pending_addr,
6440 event->attr.type, event->attr.sig_data);
6443 static void perf_pending_event_disable(struct perf_event *event)
6445 int cpu = READ_ONCE(event->pending_disable);
6450 if (cpu == smp_processor_id()) {
6451 WRITE_ONCE(event->pending_disable, -1);
6453 if (event->attr.sigtrap) {
6454 perf_sigtrap(event);
6455 atomic_set_release(&event->event_limit, 1); /* rearm event */
6459 perf_event_disable_local(event);
6466 * perf_event_disable_inatomic()
6467 * @pending_disable = CPU-A;
6471 * @pending_disable = -1;
6474 * perf_event_disable_inatomic()
6475 * @pending_disable = CPU-B;
6476 * irq_work_queue(); // FAILS
6479 * perf_pending_event()
6481 * But the event runs on CPU-B and wants disabling there.
6483 irq_work_queue_on(&event->pending, cpu);
6486 static void perf_pending_event(struct irq_work *entry)
6488 struct perf_event *event = container_of(entry, struct perf_event, pending);
6491 rctx = perf_swevent_get_recursion_context();
6493 * If we 'fail' here, that's OK, it means recursion is already disabled
6494 * and we won't recurse 'further'.
6497 perf_pending_event_disable(event);
6499 if (event->pending_wakeup) {
6500 event->pending_wakeup = 0;
6501 perf_event_wakeup(event);
6505 perf_swevent_put_recursion_context(rctx);
6508 #ifdef CONFIG_GUEST_PERF_EVENTS
6509 struct perf_guest_info_callbacks __rcu *perf_guest_cbs;
6511 DEFINE_STATIC_CALL_RET0(__perf_guest_state, *perf_guest_cbs->state);
6512 DEFINE_STATIC_CALL_RET0(__perf_guest_get_ip, *perf_guest_cbs->get_ip);
6513 DEFINE_STATIC_CALL_RET0(__perf_guest_handle_intel_pt_intr, *perf_guest_cbs->handle_intel_pt_intr);
6515 void perf_register_guest_info_callbacks(struct perf_guest_info_callbacks *cbs)
6517 if (WARN_ON_ONCE(rcu_access_pointer(perf_guest_cbs)))
6520 rcu_assign_pointer(perf_guest_cbs, cbs);
6521 static_call_update(__perf_guest_state, cbs->state);
6522 static_call_update(__perf_guest_get_ip, cbs->get_ip);
6524 /* Implementing ->handle_intel_pt_intr is optional. */
6525 if (cbs->handle_intel_pt_intr)
6526 static_call_update(__perf_guest_handle_intel_pt_intr,
6527 cbs->handle_intel_pt_intr);
6529 EXPORT_SYMBOL_GPL(perf_register_guest_info_callbacks);
6531 void perf_unregister_guest_info_callbacks(struct perf_guest_info_callbacks *cbs)
6533 if (WARN_ON_ONCE(rcu_access_pointer(perf_guest_cbs) != cbs))
6536 rcu_assign_pointer(perf_guest_cbs, NULL);
6537 static_call_update(__perf_guest_state, (void *)&__static_call_return0);
6538 static_call_update(__perf_guest_get_ip, (void *)&__static_call_return0);
6539 static_call_update(__perf_guest_handle_intel_pt_intr,
6540 (void *)&__static_call_return0);
6543 EXPORT_SYMBOL_GPL(perf_unregister_guest_info_callbacks);
6547 perf_output_sample_regs(struct perf_output_handle *handle,
6548 struct pt_regs *regs, u64 mask)
6551 DECLARE_BITMAP(_mask, 64);
6553 bitmap_from_u64(_mask, mask);
6554 for_each_set_bit(bit, _mask, sizeof(mask) * BITS_PER_BYTE) {
6557 val = perf_reg_value(regs, bit);
6558 perf_output_put(handle, val);
6562 static void perf_sample_regs_user(struct perf_regs *regs_user,
6563 struct pt_regs *regs)
6565 if (user_mode(regs)) {
6566 regs_user->abi = perf_reg_abi(current);
6567 regs_user->regs = regs;
6568 } else if (!(current->flags & PF_KTHREAD)) {
6569 perf_get_regs_user(regs_user, regs);
6571 regs_user->abi = PERF_SAMPLE_REGS_ABI_NONE;
6572 regs_user->regs = NULL;
6576 static void perf_sample_regs_intr(struct perf_regs *regs_intr,
6577 struct pt_regs *regs)
6579 regs_intr->regs = regs;
6580 regs_intr->abi = perf_reg_abi(current);
6585 * Get remaining task size from user stack pointer.
6587 * It'd be better to take stack vma map and limit this more
6588 * precisely, but there's no way to get it safely under interrupt,
6589 * so using TASK_SIZE as limit.
6591 static u64 perf_ustack_task_size(struct pt_regs *regs)
6593 unsigned long addr = perf_user_stack_pointer(regs);
6595 if (!addr || addr >= TASK_SIZE)
6598 return TASK_SIZE - addr;
6602 perf_sample_ustack_size(u16 stack_size, u16 header_size,
6603 struct pt_regs *regs)
6607 /* No regs, no stack pointer, no dump. */
6612 * Check if we fit in with the requested stack size into the:
6614 * If we don't, we limit the size to the TASK_SIZE.
6616 * - remaining sample size
6617 * If we don't, we customize the stack size to
6618 * fit in to the remaining sample size.
6621 task_size = min((u64) USHRT_MAX, perf_ustack_task_size(regs));
6622 stack_size = min(stack_size, (u16) task_size);
6624 /* Current header size plus static size and dynamic size. */
6625 header_size += 2 * sizeof(u64);
6627 /* Do we fit in with the current stack dump size? */
6628 if ((u16) (header_size + stack_size) < header_size) {
6630 * If we overflow the maximum size for the sample,
6631 * we customize the stack dump size to fit in.
6633 stack_size = USHRT_MAX - header_size - sizeof(u64);
6634 stack_size = round_up(stack_size, sizeof(u64));
6641 perf_output_sample_ustack(struct perf_output_handle *handle, u64 dump_size,
6642 struct pt_regs *regs)
6644 /* Case of a kernel thread, nothing to dump */
6647 perf_output_put(handle, size);
6656 * - the size requested by user or the best one we can fit
6657 * in to the sample max size
6659 * - user stack dump data
6661 * - the actual dumped size
6665 perf_output_put(handle, dump_size);
6668 sp = perf_user_stack_pointer(regs);
6669 rem = __output_copy_user(handle, (void *) sp, dump_size);
6670 dyn_size = dump_size - rem;
6672 perf_output_skip(handle, rem);
6675 perf_output_put(handle, dyn_size);
6679 static unsigned long perf_prepare_sample_aux(struct perf_event *event,
6680 struct perf_sample_data *data,
6683 struct perf_event *sampler = event->aux_event;
6684 struct perf_buffer *rb;
6691 if (WARN_ON_ONCE(READ_ONCE(sampler->state) != PERF_EVENT_STATE_ACTIVE))
6694 if (WARN_ON_ONCE(READ_ONCE(sampler->oncpu) != smp_processor_id()))
6697 rb = ring_buffer_get(sampler);
6702 * If this is an NMI hit inside sampling code, don't take
6703 * the sample. See also perf_aux_sample_output().
6705 if (READ_ONCE(rb->aux_in_sampling)) {
6708 size = min_t(size_t, size, perf_aux_size(rb));
6709 data->aux_size = ALIGN(size, sizeof(u64));
6711 ring_buffer_put(rb);
6714 return data->aux_size;
6717 static long perf_pmu_snapshot_aux(struct perf_buffer *rb,
6718 struct perf_event *event,
6719 struct perf_output_handle *handle,
6722 unsigned long flags;
6726 * Normal ->start()/->stop() callbacks run in IRQ mode in scheduler
6727 * paths. If we start calling them in NMI context, they may race with
6728 * the IRQ ones, that is, for example, re-starting an event that's just
6729 * been stopped, which is why we're using a separate callback that
6730 * doesn't change the event state.
6732 * IRQs need to be disabled to prevent IPIs from racing with us.
6734 local_irq_save(flags);
6736 * Guard against NMI hits inside the critical section;
6737 * see also perf_prepare_sample_aux().
6739 WRITE_ONCE(rb->aux_in_sampling, 1);
6742 ret = event->pmu->snapshot_aux(event, handle, size);
6745 WRITE_ONCE(rb->aux_in_sampling, 0);
6746 local_irq_restore(flags);
6751 static void perf_aux_sample_output(struct perf_event *event,
6752 struct perf_output_handle *handle,
6753 struct perf_sample_data *data)
6755 struct perf_event *sampler = event->aux_event;
6756 struct perf_buffer *rb;
6760 if (WARN_ON_ONCE(!sampler || !data->aux_size))
6763 rb = ring_buffer_get(sampler);
6767 size = perf_pmu_snapshot_aux(rb, sampler, handle, data->aux_size);
6770 * An error here means that perf_output_copy() failed (returned a
6771 * non-zero surplus that it didn't copy), which in its current
6772 * enlightened implementation is not possible. If that changes, we'd
6775 if (WARN_ON_ONCE(size < 0))
6779 * The pad comes from ALIGN()ing data->aux_size up to u64 in
6780 * perf_prepare_sample_aux(), so should not be more than that.
6782 pad = data->aux_size - size;
6783 if (WARN_ON_ONCE(pad >= sizeof(u64)))
6788 perf_output_copy(handle, &zero, pad);
6792 ring_buffer_put(rb);
6795 static void __perf_event_header__init_id(struct perf_event_header *header,
6796 struct perf_sample_data *data,
6797 struct perf_event *event)
6799 u64 sample_type = event->attr.sample_type;
6801 data->type = sample_type;
6802 header->size += event->id_header_size;
6804 if (sample_type & PERF_SAMPLE_TID) {
6805 /* namespace issues */
6806 data->tid_entry.pid = perf_event_pid(event, current);
6807 data->tid_entry.tid = perf_event_tid(event, current);
6810 if (sample_type & PERF_SAMPLE_TIME)
6811 data->time = perf_event_clock(event);
6813 if (sample_type & (PERF_SAMPLE_ID | PERF_SAMPLE_IDENTIFIER))
6814 data->id = primary_event_id(event);
6816 if (sample_type & PERF_SAMPLE_STREAM_ID)
6817 data->stream_id = event->id;
6819 if (sample_type & PERF_SAMPLE_CPU) {
6820 data->cpu_entry.cpu = raw_smp_processor_id();
6821 data->cpu_entry.reserved = 0;
6825 void perf_event_header__init_id(struct perf_event_header *header,
6826 struct perf_sample_data *data,
6827 struct perf_event *event)
6829 if (event->attr.sample_id_all)
6830 __perf_event_header__init_id(header, data, event);
6833 static void __perf_event__output_id_sample(struct perf_output_handle *handle,
6834 struct perf_sample_data *data)
6836 u64 sample_type = data->type;
6838 if (sample_type & PERF_SAMPLE_TID)
6839 perf_output_put(handle, data->tid_entry);
6841 if (sample_type & PERF_SAMPLE_TIME)
6842 perf_output_put(handle, data->time);
6844 if (sample_type & PERF_SAMPLE_ID)
6845 perf_output_put(handle, data->id);
6847 if (sample_type & PERF_SAMPLE_STREAM_ID)
6848 perf_output_put(handle, data->stream_id);
6850 if (sample_type & PERF_SAMPLE_CPU)
6851 perf_output_put(handle, data->cpu_entry);
6853 if (sample_type & PERF_SAMPLE_IDENTIFIER)
6854 perf_output_put(handle, data->id);
6857 void perf_event__output_id_sample(struct perf_event *event,
6858 struct perf_output_handle *handle,
6859 struct perf_sample_data *sample)
6861 if (event->attr.sample_id_all)
6862 __perf_event__output_id_sample(handle, sample);
6865 static void perf_output_read_one(struct perf_output_handle *handle,
6866 struct perf_event *event,
6867 u64 enabled, u64 running)
6869 u64 read_format = event->attr.read_format;
6873 values[n++] = perf_event_count(event);
6874 if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED) {
6875 values[n++] = enabled +
6876 atomic64_read(&event->child_total_time_enabled);
6878 if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING) {
6879 values[n++] = running +
6880 atomic64_read(&event->child_total_time_running);
6882 if (read_format & PERF_FORMAT_ID)
6883 values[n++] = primary_event_id(event);
6884 if (read_format & PERF_FORMAT_LOST)
6885 values[n++] = atomic64_read(&event->lost_samples);
6887 __output_copy(handle, values, n * sizeof(u64));
6890 static void perf_output_read_group(struct perf_output_handle *handle,
6891 struct perf_event *event,
6892 u64 enabled, u64 running)
6894 struct perf_event *leader = event->group_leader, *sub;
6895 u64 read_format = event->attr.read_format;
6899 values[n++] = 1 + leader->nr_siblings;
6901 if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED)
6902 values[n++] = enabled;
6904 if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING)
6905 values[n++] = running;
6907 if ((leader != event) &&
6908 (leader->state == PERF_EVENT_STATE_ACTIVE))
6909 leader->pmu->read(leader);
6911 values[n++] = perf_event_count(leader);
6912 if (read_format & PERF_FORMAT_ID)
6913 values[n++] = primary_event_id(leader);
6914 if (read_format & PERF_FORMAT_LOST)
6915 values[n++] = atomic64_read(&leader->lost_samples);
6917 __output_copy(handle, values, n * sizeof(u64));
6919 for_each_sibling_event(sub, leader) {
6922 if ((sub != event) &&
6923 (sub->state == PERF_EVENT_STATE_ACTIVE))
6924 sub->pmu->read(sub);
6926 values[n++] = perf_event_count(sub);
6927 if (read_format & PERF_FORMAT_ID)
6928 values[n++] = primary_event_id(sub);
6929 if (read_format & PERF_FORMAT_LOST)
6930 values[n++] = atomic64_read(&sub->lost_samples);
6932 __output_copy(handle, values, n * sizeof(u64));
6936 #define PERF_FORMAT_TOTAL_TIMES (PERF_FORMAT_TOTAL_TIME_ENABLED|\
6937 PERF_FORMAT_TOTAL_TIME_RUNNING)
6940 * XXX PERF_SAMPLE_READ vs inherited events seems difficult.
6942 * The problem is that its both hard and excessively expensive to iterate the
6943 * child list, not to mention that its impossible to IPI the children running
6944 * on another CPU, from interrupt/NMI context.
6946 static void perf_output_read(struct perf_output_handle *handle,
6947 struct perf_event *event)
6949 u64 enabled = 0, running = 0, now;
6950 u64 read_format = event->attr.read_format;
6953 * compute total_time_enabled, total_time_running
6954 * based on snapshot values taken when the event
6955 * was last scheduled in.
6957 * we cannot simply called update_context_time()
6958 * because of locking issue as we are called in
6961 if (read_format & PERF_FORMAT_TOTAL_TIMES)
6962 calc_timer_values(event, &now, &enabled, &running);
6964 if (event->attr.read_format & PERF_FORMAT_GROUP)
6965 perf_output_read_group(handle, event, enabled, running);
6967 perf_output_read_one(handle, event, enabled, running);
6970 static inline bool perf_sample_save_hw_index(struct perf_event *event)
6972 return event->attr.branch_sample_type & PERF_SAMPLE_BRANCH_HW_INDEX;
6975 void perf_output_sample(struct perf_output_handle *handle,
6976 struct perf_event_header *header,
6977 struct perf_sample_data *data,
6978 struct perf_event *event)
6980 u64 sample_type = data->type;
6982 perf_output_put(handle, *header);
6984 if (sample_type & PERF_SAMPLE_IDENTIFIER)
6985 perf_output_put(handle, data->id);
6987 if (sample_type & PERF_SAMPLE_IP)
6988 perf_output_put(handle, data->ip);
6990 if (sample_type & PERF_SAMPLE_TID)
6991 perf_output_put(handle, data->tid_entry);
6993 if (sample_type & PERF_SAMPLE_TIME)
6994 perf_output_put(handle, data->time);
6996 if (sample_type & PERF_SAMPLE_ADDR)
6997 perf_output_put(handle, data->addr);
6999 if (sample_type & PERF_SAMPLE_ID)
7000 perf_output_put(handle, data->id);
7002 if (sample_type & PERF_SAMPLE_STREAM_ID)
7003 perf_output_put(handle, data->stream_id);
7005 if (sample_type & PERF_SAMPLE_CPU)
7006 perf_output_put(handle, data->cpu_entry);
7008 if (sample_type & PERF_SAMPLE_PERIOD)
7009 perf_output_put(handle, data->period);
7011 if (sample_type & PERF_SAMPLE_READ)
7012 perf_output_read(handle, event);
7014 if (sample_type & PERF_SAMPLE_CALLCHAIN) {
7017 size += data->callchain->nr;
7018 size *= sizeof(u64);
7019 __output_copy(handle, data->callchain, size);
7022 if (sample_type & PERF_SAMPLE_RAW) {
7023 struct perf_raw_record *raw = data->raw;
7026 struct perf_raw_frag *frag = &raw->frag;
7028 perf_output_put(handle, raw->size);
7031 __output_custom(handle, frag->copy,
7032 frag->data, frag->size);
7034 __output_copy(handle, frag->data,
7037 if (perf_raw_frag_last(frag))
7042 __output_skip(handle, NULL, frag->pad);
7048 .size = sizeof(u32),
7051 perf_output_put(handle, raw);
7055 if (sample_type & PERF_SAMPLE_BRANCH_STACK) {
7056 if (data->br_stack) {
7059 size = data->br_stack->nr
7060 * sizeof(struct perf_branch_entry);
7062 perf_output_put(handle, data->br_stack->nr);
7063 if (perf_sample_save_hw_index(event))
7064 perf_output_put(handle, data->br_stack->hw_idx);
7065 perf_output_copy(handle, data->br_stack->entries, size);
7068 * we always store at least the value of nr
7071 perf_output_put(handle, nr);
7075 if (sample_type & PERF_SAMPLE_REGS_USER) {
7076 u64 abi = data->regs_user.abi;
7079 * If there are no regs to dump, notice it through
7080 * first u64 being zero (PERF_SAMPLE_REGS_ABI_NONE).
7082 perf_output_put(handle, abi);
7085 u64 mask = event->attr.sample_regs_user;
7086 perf_output_sample_regs(handle,
7087 data->regs_user.regs,
7092 if (sample_type & PERF_SAMPLE_STACK_USER) {
7093 perf_output_sample_ustack(handle,
7094 data->stack_user_size,
7095 data->regs_user.regs);
7098 if (sample_type & PERF_SAMPLE_WEIGHT_TYPE)
7099 perf_output_put(handle, data->weight.full);
7101 if (sample_type & PERF_SAMPLE_DATA_SRC)
7102 perf_output_put(handle, data->data_src.val);
7104 if (sample_type & PERF_SAMPLE_TRANSACTION)
7105 perf_output_put(handle, data->txn);
7107 if (sample_type & PERF_SAMPLE_REGS_INTR) {
7108 u64 abi = data->regs_intr.abi;
7110 * If there are no regs to dump, notice it through
7111 * first u64 being zero (PERF_SAMPLE_REGS_ABI_NONE).
7113 perf_output_put(handle, abi);
7116 u64 mask = event->attr.sample_regs_intr;
7118 perf_output_sample_regs(handle,
7119 data->regs_intr.regs,
7124 if (sample_type & PERF_SAMPLE_PHYS_ADDR)
7125 perf_output_put(handle, data->phys_addr);
7127 if (sample_type & PERF_SAMPLE_CGROUP)
7128 perf_output_put(handle, data->cgroup);
7130 if (sample_type & PERF_SAMPLE_DATA_PAGE_SIZE)
7131 perf_output_put(handle, data->data_page_size);
7133 if (sample_type & PERF_SAMPLE_CODE_PAGE_SIZE)
7134 perf_output_put(handle, data->code_page_size);
7136 if (sample_type & PERF_SAMPLE_AUX) {
7137 perf_output_put(handle, data->aux_size);
7140 perf_aux_sample_output(event, handle, data);
7143 if (!event->attr.watermark) {
7144 int wakeup_events = event->attr.wakeup_events;
7146 if (wakeup_events) {
7147 struct perf_buffer *rb = handle->rb;
7148 int events = local_inc_return(&rb->events);
7150 if (events >= wakeup_events) {
7151 local_sub(wakeup_events, &rb->events);
7152 local_inc(&rb->wakeup);
7158 static u64 perf_virt_to_phys(u64 virt)
7165 if (virt >= TASK_SIZE) {
7166 /* If it's vmalloc()d memory, leave phys_addr as 0 */
7167 if (virt_addr_valid((void *)(uintptr_t)virt) &&
7168 !(virt >= VMALLOC_START && virt < VMALLOC_END))
7169 phys_addr = (u64)virt_to_phys((void *)(uintptr_t)virt);
7172 * Walking the pages tables for user address.
7173 * Interrupts are disabled, so it prevents any tear down
7174 * of the page tables.
7175 * Try IRQ-safe get_user_page_fast_only first.
7176 * If failed, leave phys_addr as 0.
7178 if (current->mm != NULL) {
7181 pagefault_disable();
7182 if (get_user_page_fast_only(virt, 0, &p)) {
7183 phys_addr = page_to_phys(p) + virt % PAGE_SIZE;
7194 * Return the pagetable size of a given virtual address.
7196 static u64 perf_get_pgtable_size(struct mm_struct *mm, unsigned long addr)
7200 #ifdef CONFIG_HAVE_FAST_GUP
7207 pgdp = pgd_offset(mm, addr);
7208 pgd = READ_ONCE(*pgdp);
7213 return pgd_leaf_size(pgd);
7215 p4dp = p4d_offset_lockless(pgdp, pgd, addr);
7216 p4d = READ_ONCE(*p4dp);
7217 if (!p4d_present(p4d))
7221 return p4d_leaf_size(p4d);
7223 pudp = pud_offset_lockless(p4dp, p4d, addr);
7224 pud = READ_ONCE(*pudp);
7225 if (!pud_present(pud))
7229 return pud_leaf_size(pud);
7231 pmdp = pmd_offset_lockless(pudp, pud, addr);
7232 pmd = READ_ONCE(*pmdp);
7233 if (!pmd_present(pmd))
7237 return pmd_leaf_size(pmd);
7239 ptep = pte_offset_map(&pmd, addr);
7240 pte = ptep_get_lockless(ptep);
7241 if (pte_present(pte))
7242 size = pte_leaf_size(pte);
7244 #endif /* CONFIG_HAVE_FAST_GUP */
7249 static u64 perf_get_page_size(unsigned long addr)
7251 struct mm_struct *mm;
7252 unsigned long flags;
7259 * Software page-table walkers must disable IRQs,
7260 * which prevents any tear down of the page tables.
7262 local_irq_save(flags);
7267 * For kernel threads and the like, use init_mm so that
7268 * we can find kernel memory.
7273 size = perf_get_pgtable_size(mm, addr);
7275 local_irq_restore(flags);
7280 static struct perf_callchain_entry __empty_callchain = { .nr = 0, };
7282 struct perf_callchain_entry *
7283 perf_callchain(struct perf_event *event, struct pt_regs *regs)
7285 bool kernel = !event->attr.exclude_callchain_kernel;
7286 bool user = !event->attr.exclude_callchain_user;
7287 /* Disallow cross-task user callchains. */
7288 bool crosstask = event->ctx->task && event->ctx->task != current;
7289 const u32 max_stack = event->attr.sample_max_stack;
7290 struct perf_callchain_entry *callchain;
7292 if (!kernel && !user)
7293 return &__empty_callchain;
7295 callchain = get_perf_callchain(regs, 0, kernel, user,
7296 max_stack, crosstask, true);
7297 return callchain ?: &__empty_callchain;
7300 void perf_prepare_sample(struct perf_event_header *header,
7301 struct perf_sample_data *data,
7302 struct perf_event *event,
7303 struct pt_regs *regs)
7305 u64 sample_type = event->attr.sample_type;
7307 header->type = PERF_RECORD_SAMPLE;
7308 header->size = sizeof(*header) + event->header_size;
7311 header->misc |= perf_misc_flags(regs);
7313 __perf_event_header__init_id(header, data, event);
7315 if (sample_type & (PERF_SAMPLE_IP | PERF_SAMPLE_CODE_PAGE_SIZE))
7316 data->ip = perf_instruction_pointer(regs);
7318 if (sample_type & PERF_SAMPLE_CALLCHAIN) {
7321 if (!(sample_type & __PERF_SAMPLE_CALLCHAIN_EARLY))
7322 data->callchain = perf_callchain(event, regs);
7324 size += data->callchain->nr;
7326 header->size += size * sizeof(u64);
7329 if (sample_type & PERF_SAMPLE_RAW) {
7330 struct perf_raw_record *raw = data->raw;
7334 struct perf_raw_frag *frag = &raw->frag;
7339 if (perf_raw_frag_last(frag))
7344 size = round_up(sum + sizeof(u32), sizeof(u64));
7345 raw->size = size - sizeof(u32);
7346 frag->pad = raw->size - sum;
7351 header->size += size;
7354 if (sample_type & PERF_SAMPLE_BRANCH_STACK) {
7355 int size = sizeof(u64); /* nr */
7356 if (data->br_stack) {
7357 if (perf_sample_save_hw_index(event))
7358 size += sizeof(u64);
7360 size += data->br_stack->nr
7361 * sizeof(struct perf_branch_entry);
7363 header->size += size;
7366 if (sample_type & (PERF_SAMPLE_REGS_USER | PERF_SAMPLE_STACK_USER))
7367 perf_sample_regs_user(&data->regs_user, regs);
7369 if (sample_type & PERF_SAMPLE_REGS_USER) {
7370 /* regs dump ABI info */
7371 int size = sizeof(u64);
7373 if (data->regs_user.regs) {
7374 u64 mask = event->attr.sample_regs_user;
7375 size += hweight64(mask) * sizeof(u64);
7378 header->size += size;
7381 if (sample_type & PERF_SAMPLE_STACK_USER) {
7383 * Either we need PERF_SAMPLE_STACK_USER bit to be always
7384 * processed as the last one or have additional check added
7385 * in case new sample type is added, because we could eat
7386 * up the rest of the sample size.
7388 u16 stack_size = event->attr.sample_stack_user;
7389 u16 size = sizeof(u64);
7391 stack_size = perf_sample_ustack_size(stack_size, header->size,
7392 data->regs_user.regs);
7395 * If there is something to dump, add space for the dump
7396 * itself and for the field that tells the dynamic size,
7397 * which is how many have been actually dumped.
7400 size += sizeof(u64) + stack_size;
7402 data->stack_user_size = stack_size;
7403 header->size += size;
7406 if (sample_type & PERF_SAMPLE_REGS_INTR) {
7407 /* regs dump ABI info */
7408 int size = sizeof(u64);
7410 perf_sample_regs_intr(&data->regs_intr, regs);
7412 if (data->regs_intr.regs) {
7413 u64 mask = event->attr.sample_regs_intr;
7415 size += hweight64(mask) * sizeof(u64);
7418 header->size += size;
7421 if (sample_type & PERF_SAMPLE_PHYS_ADDR)
7422 data->phys_addr = perf_virt_to_phys(data->addr);
7424 #ifdef CONFIG_CGROUP_PERF
7425 if (sample_type & PERF_SAMPLE_CGROUP) {
7426 struct cgroup *cgrp;
7428 /* protected by RCU */
7429 cgrp = task_css_check(current, perf_event_cgrp_id, 1)->cgroup;
7430 data->cgroup = cgroup_id(cgrp);
7435 * PERF_DATA_PAGE_SIZE requires PERF_SAMPLE_ADDR. If the user doesn't
7436 * require PERF_SAMPLE_ADDR, kernel implicitly retrieve the data->addr,
7437 * but the value will not dump to the userspace.
7439 if (sample_type & PERF_SAMPLE_DATA_PAGE_SIZE)
7440 data->data_page_size = perf_get_page_size(data->addr);
7442 if (sample_type & PERF_SAMPLE_CODE_PAGE_SIZE)
7443 data->code_page_size = perf_get_page_size(data->ip);
7445 if (sample_type & PERF_SAMPLE_AUX) {
7448 header->size += sizeof(u64); /* size */
7451 * Given the 16bit nature of header::size, an AUX sample can
7452 * easily overflow it, what with all the preceding sample bits.
7453 * Make sure this doesn't happen by using up to U16_MAX bytes
7454 * per sample in total (rounded down to 8 byte boundary).
7456 size = min_t(size_t, U16_MAX - header->size,
7457 event->attr.aux_sample_size);
7458 size = rounddown(size, 8);
7459 size = perf_prepare_sample_aux(event, data, size);
7461 WARN_ON_ONCE(size + header->size > U16_MAX);
7462 header->size += size;
7465 * If you're adding more sample types here, you likely need to do
7466 * something about the overflowing header::size, like repurpose the
7467 * lowest 3 bits of size, which should be always zero at the moment.
7468 * This raises a more important question, do we really need 512k sized
7469 * samples and why, so good argumentation is in order for whatever you
7472 WARN_ON_ONCE(header->size & 7);
7475 static __always_inline int
7476 __perf_event_output(struct perf_event *event,
7477 struct perf_sample_data *data,
7478 struct pt_regs *regs,
7479 int (*output_begin)(struct perf_output_handle *,
7480 struct perf_sample_data *,
7481 struct perf_event *,
7484 struct perf_output_handle handle;
7485 struct perf_event_header header;
7488 /* protect the callchain buffers */
7491 perf_prepare_sample(&header, data, event, regs);
7493 err = output_begin(&handle, data, event, header.size);
7497 perf_output_sample(&handle, &header, data, event);
7499 perf_output_end(&handle);
7507 perf_event_output_forward(struct perf_event *event,
7508 struct perf_sample_data *data,
7509 struct pt_regs *regs)
7511 __perf_event_output(event, data, regs, perf_output_begin_forward);
7515 perf_event_output_backward(struct perf_event *event,
7516 struct perf_sample_data *data,
7517 struct pt_regs *regs)
7519 __perf_event_output(event, data, regs, perf_output_begin_backward);
7523 perf_event_output(struct perf_event *event,
7524 struct perf_sample_data *data,
7525 struct pt_regs *regs)
7527 return __perf_event_output(event, data, regs, perf_output_begin);
7534 struct perf_read_event {
7535 struct perf_event_header header;
7542 perf_event_read_event(struct perf_event *event,
7543 struct task_struct *task)
7545 struct perf_output_handle handle;
7546 struct perf_sample_data sample;
7547 struct perf_read_event read_event = {
7549 .type = PERF_RECORD_READ,
7551 .size = sizeof(read_event) + event->read_size,
7553 .pid = perf_event_pid(event, task),
7554 .tid = perf_event_tid(event, task),
7558 perf_event_header__init_id(&read_event.header, &sample, event);
7559 ret = perf_output_begin(&handle, &sample, event, read_event.header.size);
7563 perf_output_put(&handle, read_event);
7564 perf_output_read(&handle, event);
7565 perf_event__output_id_sample(event, &handle, &sample);
7567 perf_output_end(&handle);
7570 typedef void (perf_iterate_f)(struct perf_event *event, void *data);
7573 perf_iterate_ctx(struct perf_event_context *ctx,
7574 perf_iterate_f output,
7575 void *data, bool all)
7577 struct perf_event *event;
7579 list_for_each_entry_rcu(event, &ctx->event_list, event_entry) {
7581 if (event->state < PERF_EVENT_STATE_INACTIVE)
7583 if (!event_filter_match(event))
7587 output(event, data);
7591 static void perf_iterate_sb_cpu(perf_iterate_f output, void *data)
7593 struct pmu_event_list *pel = this_cpu_ptr(&pmu_sb_events);
7594 struct perf_event *event;
7596 list_for_each_entry_rcu(event, &pel->list, sb_list) {
7598 * Skip events that are not fully formed yet; ensure that
7599 * if we observe event->ctx, both event and ctx will be
7600 * complete enough. See perf_install_in_context().
7602 if (!smp_load_acquire(&event->ctx))
7605 if (event->state < PERF_EVENT_STATE_INACTIVE)
7607 if (!event_filter_match(event))
7609 output(event, data);
7614 * Iterate all events that need to receive side-band events.
7616 * For new callers; ensure that account_pmu_sb_event() includes
7617 * your event, otherwise it might not get delivered.
7620 perf_iterate_sb(perf_iterate_f output, void *data,
7621 struct perf_event_context *task_ctx)
7623 struct perf_event_context *ctx;
7630 * If we have task_ctx != NULL we only notify the task context itself.
7631 * The task_ctx is set only for EXIT events before releasing task
7635 perf_iterate_ctx(task_ctx, output, data, false);
7639 perf_iterate_sb_cpu(output, data);
7641 for_each_task_context_nr(ctxn) {
7642 ctx = rcu_dereference(current->perf_event_ctxp[ctxn]);
7644 perf_iterate_ctx(ctx, output, data, false);
7652 * Clear all file-based filters at exec, they'll have to be
7653 * re-instated when/if these objects are mmapped again.
7655 static void perf_event_addr_filters_exec(struct perf_event *event, void *data)
7657 struct perf_addr_filters_head *ifh = perf_event_addr_filters(event);
7658 struct perf_addr_filter *filter;
7659 unsigned int restart = 0, count = 0;
7660 unsigned long flags;
7662 if (!has_addr_filter(event))
7665 raw_spin_lock_irqsave(&ifh->lock, flags);
7666 list_for_each_entry(filter, &ifh->list, entry) {
7667 if (filter->path.dentry) {
7668 event->addr_filter_ranges[count].start = 0;
7669 event->addr_filter_ranges[count].size = 0;
7677 event->addr_filters_gen++;
7678 raw_spin_unlock_irqrestore(&ifh->lock, flags);
7681 perf_event_stop(event, 1);
7684 void perf_event_exec(void)
7686 struct perf_event_context *ctx;
7689 for_each_task_context_nr(ctxn) {
7690 perf_event_enable_on_exec(ctxn);
7691 perf_event_remove_on_exec(ctxn);
7694 ctx = rcu_dereference(current->perf_event_ctxp[ctxn]);
7696 perf_iterate_ctx(ctx, perf_event_addr_filters_exec,
7703 struct remote_output {
7704 struct perf_buffer *rb;
7708 static void __perf_event_output_stop(struct perf_event *event, void *data)
7710 struct perf_event *parent = event->parent;
7711 struct remote_output *ro = data;
7712 struct perf_buffer *rb = ro->rb;
7713 struct stop_event_data sd = {
7717 if (!has_aux(event))
7724 * In case of inheritance, it will be the parent that links to the
7725 * ring-buffer, but it will be the child that's actually using it.
7727 * We are using event::rb to determine if the event should be stopped,
7728 * however this may race with ring_buffer_attach() (through set_output),
7729 * which will make us skip the event that actually needs to be stopped.
7730 * So ring_buffer_attach() has to stop an aux event before re-assigning
7733 if (rcu_dereference(parent->rb) == rb)
7734 ro->err = __perf_event_stop(&sd);
7737 static int __perf_pmu_output_stop(void *info)
7739 struct perf_event *event = info;
7740 struct pmu *pmu = event->ctx->pmu;
7741 struct perf_cpu_context *cpuctx = this_cpu_ptr(pmu->pmu_cpu_context);
7742 struct remote_output ro = {
7747 perf_iterate_ctx(&cpuctx->ctx, __perf_event_output_stop, &ro, false);
7748 if (cpuctx->task_ctx)
7749 perf_iterate_ctx(cpuctx->task_ctx, __perf_event_output_stop,
7756 static void perf_pmu_output_stop(struct perf_event *event)
7758 struct perf_event *iter;
7763 list_for_each_entry_rcu(iter, &event->rb->event_list, rb_entry) {
7765 * For per-CPU events, we need to make sure that neither they
7766 * nor their children are running; for cpu==-1 events it's
7767 * sufficient to stop the event itself if it's active, since
7768 * it can't have children.
7772 cpu = READ_ONCE(iter->oncpu);
7777 err = cpu_function_call(cpu, __perf_pmu_output_stop, event);
7778 if (err == -EAGAIN) {
7787 * task tracking -- fork/exit
7789 * enabled by: attr.comm | attr.mmap | attr.mmap2 | attr.mmap_data | attr.task
7792 struct perf_task_event {
7793 struct task_struct *task;
7794 struct perf_event_context *task_ctx;
7797 struct perf_event_header header;
7807 static int perf_event_task_match(struct perf_event *event)
7809 return event->attr.comm || event->attr.mmap ||
7810 event->attr.mmap2 || event->attr.mmap_data ||
7814 static void perf_event_task_output(struct perf_event *event,
7817 struct perf_task_event *task_event = data;
7818 struct perf_output_handle handle;
7819 struct perf_sample_data sample;
7820 struct task_struct *task = task_event->task;
7821 int ret, size = task_event->event_id.header.size;
7823 if (!perf_event_task_match(event))
7826 perf_event_header__init_id(&task_event->event_id.header, &sample, event);
7828 ret = perf_output_begin(&handle, &sample, event,
7829 task_event->event_id.header.size);
7833 task_event->event_id.pid = perf_event_pid(event, task);
7834 task_event->event_id.tid = perf_event_tid(event, task);
7836 if (task_event->event_id.header.type == PERF_RECORD_EXIT) {
7837 task_event->event_id.ppid = perf_event_pid(event,
7839 task_event->event_id.ptid = perf_event_pid(event,
7841 } else { /* PERF_RECORD_FORK */
7842 task_event->event_id.ppid = perf_event_pid(event, current);
7843 task_event->event_id.ptid = perf_event_tid(event, current);
7846 task_event->event_id.time = perf_event_clock(event);
7848 perf_output_put(&handle, task_event->event_id);
7850 perf_event__output_id_sample(event, &handle, &sample);
7852 perf_output_end(&handle);
7854 task_event->event_id.header.size = size;
7857 static void perf_event_task(struct task_struct *task,
7858 struct perf_event_context *task_ctx,
7861 struct perf_task_event task_event;
7863 if (!atomic_read(&nr_comm_events) &&
7864 !atomic_read(&nr_mmap_events) &&
7865 !atomic_read(&nr_task_events))
7868 task_event = (struct perf_task_event){
7870 .task_ctx = task_ctx,
7873 .type = new ? PERF_RECORD_FORK : PERF_RECORD_EXIT,
7875 .size = sizeof(task_event.event_id),
7885 perf_iterate_sb(perf_event_task_output,
7890 void perf_event_fork(struct task_struct *task)
7892 perf_event_task(task, NULL, 1);
7893 perf_event_namespaces(task);
7900 struct perf_comm_event {
7901 struct task_struct *task;
7906 struct perf_event_header header;
7913 static int perf_event_comm_match(struct perf_event *event)
7915 return event->attr.comm;
7918 static void perf_event_comm_output(struct perf_event *event,
7921 struct perf_comm_event *comm_event = data;
7922 struct perf_output_handle handle;
7923 struct perf_sample_data sample;
7924 int size = comm_event->event_id.header.size;
7927 if (!perf_event_comm_match(event))
7930 perf_event_header__init_id(&comm_event->event_id.header, &sample, event);
7931 ret = perf_output_begin(&handle, &sample, event,
7932 comm_event->event_id.header.size);
7937 comm_event->event_id.pid = perf_event_pid(event, comm_event->task);
7938 comm_event->event_id.tid = perf_event_tid(event, comm_event->task);
7940 perf_output_put(&handle, comm_event->event_id);
7941 __output_copy(&handle, comm_event->comm,
7942 comm_event->comm_size);
7944 perf_event__output_id_sample(event, &handle, &sample);
7946 perf_output_end(&handle);
7948 comm_event->event_id.header.size = size;
7951 static void perf_event_comm_event(struct perf_comm_event *comm_event)
7953 char comm[TASK_COMM_LEN];
7956 memset(comm, 0, sizeof(comm));
7957 strlcpy(comm, comm_event->task->comm, sizeof(comm));
7958 size = ALIGN(strlen(comm)+1, sizeof(u64));
7960 comm_event->comm = comm;
7961 comm_event->comm_size = size;
7963 comm_event->event_id.header.size = sizeof(comm_event->event_id) + size;
7965 perf_iterate_sb(perf_event_comm_output,
7970 void perf_event_comm(struct task_struct *task, bool exec)
7972 struct perf_comm_event comm_event;
7974 if (!atomic_read(&nr_comm_events))
7977 comm_event = (struct perf_comm_event){
7983 .type = PERF_RECORD_COMM,
7984 .misc = exec ? PERF_RECORD_MISC_COMM_EXEC : 0,
7992 perf_event_comm_event(&comm_event);
7996 * namespaces tracking
7999 struct perf_namespaces_event {
8000 struct task_struct *task;
8003 struct perf_event_header header;
8008 struct perf_ns_link_info link_info[NR_NAMESPACES];
8012 static int perf_event_namespaces_match(struct perf_event *event)
8014 return event->attr.namespaces;
8017 static void perf_event_namespaces_output(struct perf_event *event,
8020 struct perf_namespaces_event *namespaces_event = data;
8021 struct perf_output_handle handle;
8022 struct perf_sample_data sample;
8023 u16 header_size = namespaces_event->event_id.header.size;
8026 if (!perf_event_namespaces_match(event))
8029 perf_event_header__init_id(&namespaces_event->event_id.header,
8031 ret = perf_output_begin(&handle, &sample, event,
8032 namespaces_event->event_id.header.size);
8036 namespaces_event->event_id.pid = perf_event_pid(event,
8037 namespaces_event->task);
8038 namespaces_event->event_id.tid = perf_event_tid(event,
8039 namespaces_event->task);
8041 perf_output_put(&handle, namespaces_event->event_id);
8043 perf_event__output_id_sample(event, &handle, &sample);
8045 perf_output_end(&handle);
8047 namespaces_event->event_id.header.size = header_size;
8050 static void perf_fill_ns_link_info(struct perf_ns_link_info *ns_link_info,
8051 struct task_struct *task,
8052 const struct proc_ns_operations *ns_ops)
8054 struct path ns_path;
8055 struct inode *ns_inode;
8058 error = ns_get_path(&ns_path, task, ns_ops);
8060 ns_inode = ns_path.dentry->d_inode;
8061 ns_link_info->dev = new_encode_dev(ns_inode->i_sb->s_dev);
8062 ns_link_info->ino = ns_inode->i_ino;
8067 void perf_event_namespaces(struct task_struct *task)
8069 struct perf_namespaces_event namespaces_event;
8070 struct perf_ns_link_info *ns_link_info;
8072 if (!atomic_read(&nr_namespaces_events))
8075 namespaces_event = (struct perf_namespaces_event){
8079 .type = PERF_RECORD_NAMESPACES,
8081 .size = sizeof(namespaces_event.event_id),
8085 .nr_namespaces = NR_NAMESPACES,
8086 /* .link_info[NR_NAMESPACES] */
8090 ns_link_info = namespaces_event.event_id.link_info;
8092 perf_fill_ns_link_info(&ns_link_info[MNT_NS_INDEX],
8093 task, &mntns_operations);
8095 #ifdef CONFIG_USER_NS
8096 perf_fill_ns_link_info(&ns_link_info[USER_NS_INDEX],
8097 task, &userns_operations);
8099 #ifdef CONFIG_NET_NS
8100 perf_fill_ns_link_info(&ns_link_info[NET_NS_INDEX],
8101 task, &netns_operations);
8103 #ifdef CONFIG_UTS_NS
8104 perf_fill_ns_link_info(&ns_link_info[UTS_NS_INDEX],
8105 task, &utsns_operations);
8107 #ifdef CONFIG_IPC_NS
8108 perf_fill_ns_link_info(&ns_link_info[IPC_NS_INDEX],
8109 task, &ipcns_operations);
8111 #ifdef CONFIG_PID_NS
8112 perf_fill_ns_link_info(&ns_link_info[PID_NS_INDEX],
8113 task, &pidns_operations);
8115 #ifdef CONFIG_CGROUPS
8116 perf_fill_ns_link_info(&ns_link_info[CGROUP_NS_INDEX],
8117 task, &cgroupns_operations);
8120 perf_iterate_sb(perf_event_namespaces_output,
8128 #ifdef CONFIG_CGROUP_PERF
8130 struct perf_cgroup_event {
8134 struct perf_event_header header;
8140 static int perf_event_cgroup_match(struct perf_event *event)
8142 return event->attr.cgroup;
8145 static void perf_event_cgroup_output(struct perf_event *event, void *data)
8147 struct perf_cgroup_event *cgroup_event = data;
8148 struct perf_output_handle handle;
8149 struct perf_sample_data sample;
8150 u16 header_size = cgroup_event->event_id.header.size;
8153 if (!perf_event_cgroup_match(event))
8156 perf_event_header__init_id(&cgroup_event->event_id.header,
8158 ret = perf_output_begin(&handle, &sample, event,
8159 cgroup_event->event_id.header.size);
8163 perf_output_put(&handle, cgroup_event->event_id);
8164 __output_copy(&handle, cgroup_event->path, cgroup_event->path_size);
8166 perf_event__output_id_sample(event, &handle, &sample);
8168 perf_output_end(&handle);
8170 cgroup_event->event_id.header.size = header_size;
8173 static void perf_event_cgroup(struct cgroup *cgrp)
8175 struct perf_cgroup_event cgroup_event;
8176 char path_enomem[16] = "//enomem";
8180 if (!atomic_read(&nr_cgroup_events))
8183 cgroup_event = (struct perf_cgroup_event){
8186 .type = PERF_RECORD_CGROUP,
8188 .size = sizeof(cgroup_event.event_id),
8190 .id = cgroup_id(cgrp),
8194 pathname = kmalloc(PATH_MAX, GFP_KERNEL);
8195 if (pathname == NULL) {
8196 cgroup_event.path = path_enomem;
8198 /* just to be sure to have enough space for alignment */
8199 cgroup_path(cgrp, pathname, PATH_MAX - sizeof(u64));
8200 cgroup_event.path = pathname;
8204 * Since our buffer works in 8 byte units we need to align our string
8205 * size to a multiple of 8. However, we must guarantee the tail end is
8206 * zero'd out to avoid leaking random bits to userspace.
8208 size = strlen(cgroup_event.path) + 1;
8209 while (!IS_ALIGNED(size, sizeof(u64)))
8210 cgroup_event.path[size++] = '\0';
8212 cgroup_event.event_id.header.size += size;
8213 cgroup_event.path_size = size;
8215 perf_iterate_sb(perf_event_cgroup_output,
8228 struct perf_mmap_event {
8229 struct vm_area_struct *vma;
8231 const char *file_name;
8237 u8 build_id[BUILD_ID_SIZE_MAX];
8241 struct perf_event_header header;
8251 static int perf_event_mmap_match(struct perf_event *event,
8254 struct perf_mmap_event *mmap_event = data;
8255 struct vm_area_struct *vma = mmap_event->vma;
8256 int executable = vma->vm_flags & VM_EXEC;
8258 return (!executable && event->attr.mmap_data) ||
8259 (executable && (event->attr.mmap || event->attr.mmap2));
8262 static void perf_event_mmap_output(struct perf_event *event,
8265 struct perf_mmap_event *mmap_event = data;
8266 struct perf_output_handle handle;
8267 struct perf_sample_data sample;
8268 int size = mmap_event->event_id.header.size;
8269 u32 type = mmap_event->event_id.header.type;
8273 if (!perf_event_mmap_match(event, data))
8276 if (event->attr.mmap2) {
8277 mmap_event->event_id.header.type = PERF_RECORD_MMAP2;
8278 mmap_event->event_id.header.size += sizeof(mmap_event->maj);
8279 mmap_event->event_id.header.size += sizeof(mmap_event->min);
8280 mmap_event->event_id.header.size += sizeof(mmap_event->ino);
8281 mmap_event->event_id.header.size += sizeof(mmap_event->ino_generation);
8282 mmap_event->event_id.header.size += sizeof(mmap_event->prot);
8283 mmap_event->event_id.header.size += sizeof(mmap_event->flags);
8286 perf_event_header__init_id(&mmap_event->event_id.header, &sample, event);
8287 ret = perf_output_begin(&handle, &sample, event,
8288 mmap_event->event_id.header.size);
8292 mmap_event->event_id.pid = perf_event_pid(event, current);
8293 mmap_event->event_id.tid = perf_event_tid(event, current);
8295 use_build_id = event->attr.build_id && mmap_event->build_id_size;
8297 if (event->attr.mmap2 && use_build_id)
8298 mmap_event->event_id.header.misc |= PERF_RECORD_MISC_MMAP_BUILD_ID;
8300 perf_output_put(&handle, mmap_event->event_id);
8302 if (event->attr.mmap2) {
8304 u8 size[4] = { (u8) mmap_event->build_id_size, 0, 0, 0 };
8306 __output_copy(&handle, size, 4);
8307 __output_copy(&handle, mmap_event->build_id, BUILD_ID_SIZE_MAX);
8309 perf_output_put(&handle, mmap_event->maj);
8310 perf_output_put(&handle, mmap_event->min);
8311 perf_output_put(&handle, mmap_event->ino);
8312 perf_output_put(&handle, mmap_event->ino_generation);
8314 perf_output_put(&handle, mmap_event->prot);
8315 perf_output_put(&handle, mmap_event->flags);
8318 __output_copy(&handle, mmap_event->file_name,
8319 mmap_event->file_size);
8321 perf_event__output_id_sample(event, &handle, &sample);
8323 perf_output_end(&handle);
8325 mmap_event->event_id.header.size = size;
8326 mmap_event->event_id.header.type = type;
8329 static void perf_event_mmap_event(struct perf_mmap_event *mmap_event)
8331 struct vm_area_struct *vma = mmap_event->vma;
8332 struct file *file = vma->vm_file;
8333 int maj = 0, min = 0;
8334 u64 ino = 0, gen = 0;
8335 u32 prot = 0, flags = 0;
8341 if (vma->vm_flags & VM_READ)
8343 if (vma->vm_flags & VM_WRITE)
8345 if (vma->vm_flags & VM_EXEC)
8348 if (vma->vm_flags & VM_MAYSHARE)
8351 flags = MAP_PRIVATE;
8353 if (vma->vm_flags & VM_LOCKED)
8354 flags |= MAP_LOCKED;
8355 if (is_vm_hugetlb_page(vma))
8356 flags |= MAP_HUGETLB;
8359 struct inode *inode;
8362 buf = kmalloc(PATH_MAX, GFP_KERNEL);
8368 * d_path() works from the end of the rb backwards, so we
8369 * need to add enough zero bytes after the string to handle
8370 * the 64bit alignment we do later.
8372 name = file_path(file, buf, PATH_MAX - sizeof(u64));
8377 inode = file_inode(vma->vm_file);
8378 dev = inode->i_sb->s_dev;
8380 gen = inode->i_generation;
8386 if (vma->vm_ops && vma->vm_ops->name) {
8387 name = (char *) vma->vm_ops->name(vma);
8392 name = (char *)arch_vma_name(vma);
8396 if (vma->vm_start <= vma->vm_mm->start_brk &&
8397 vma->vm_end >= vma->vm_mm->brk) {
8401 if (vma->vm_start <= vma->vm_mm->start_stack &&
8402 vma->vm_end >= vma->vm_mm->start_stack) {
8412 strlcpy(tmp, name, sizeof(tmp));
8416 * Since our buffer works in 8 byte units we need to align our string
8417 * size to a multiple of 8. However, we must guarantee the tail end is
8418 * zero'd out to avoid leaking random bits to userspace.
8420 size = strlen(name)+1;
8421 while (!IS_ALIGNED(size, sizeof(u64)))
8422 name[size++] = '\0';
8424 mmap_event->file_name = name;
8425 mmap_event->file_size = size;
8426 mmap_event->maj = maj;
8427 mmap_event->min = min;
8428 mmap_event->ino = ino;
8429 mmap_event->ino_generation = gen;
8430 mmap_event->prot = prot;
8431 mmap_event->flags = flags;
8433 if (!(vma->vm_flags & VM_EXEC))
8434 mmap_event->event_id.header.misc |= PERF_RECORD_MISC_MMAP_DATA;
8436 mmap_event->event_id.header.size = sizeof(mmap_event->event_id) + size;
8438 if (atomic_read(&nr_build_id_events))
8439 build_id_parse(vma, mmap_event->build_id, &mmap_event->build_id_size);
8441 perf_iterate_sb(perf_event_mmap_output,
8449 * Check whether inode and address range match filter criteria.
8451 static bool perf_addr_filter_match(struct perf_addr_filter *filter,
8452 struct file *file, unsigned long offset,
8455 /* d_inode(NULL) won't be equal to any mapped user-space file */
8456 if (!filter->path.dentry)
8459 if (d_inode(filter->path.dentry) != file_inode(file))
8462 if (filter->offset > offset + size)
8465 if (filter->offset + filter->size < offset)
8471 static bool perf_addr_filter_vma_adjust(struct perf_addr_filter *filter,
8472 struct vm_area_struct *vma,
8473 struct perf_addr_filter_range *fr)
8475 unsigned long vma_size = vma->vm_end - vma->vm_start;
8476 unsigned long off = vma->vm_pgoff << PAGE_SHIFT;
8477 struct file *file = vma->vm_file;
8479 if (!perf_addr_filter_match(filter, file, off, vma_size))
8482 if (filter->offset < off) {
8483 fr->start = vma->vm_start;
8484 fr->size = min(vma_size, filter->size - (off - filter->offset));
8486 fr->start = vma->vm_start + filter->offset - off;
8487 fr->size = min(vma->vm_end - fr->start, filter->size);
8493 static void __perf_addr_filters_adjust(struct perf_event *event, void *data)
8495 struct perf_addr_filters_head *ifh = perf_event_addr_filters(event);
8496 struct vm_area_struct *vma = data;
8497 struct perf_addr_filter *filter;
8498 unsigned int restart = 0, count = 0;
8499 unsigned long flags;
8501 if (!has_addr_filter(event))
8507 raw_spin_lock_irqsave(&ifh->lock, flags);
8508 list_for_each_entry(filter, &ifh->list, entry) {
8509 if (perf_addr_filter_vma_adjust(filter, vma,
8510 &event->addr_filter_ranges[count]))
8517 event->addr_filters_gen++;
8518 raw_spin_unlock_irqrestore(&ifh->lock, flags);
8521 perf_event_stop(event, 1);
8525 * Adjust all task's events' filters to the new vma
8527 static void perf_addr_filters_adjust(struct vm_area_struct *vma)
8529 struct perf_event_context *ctx;
8533 * Data tracing isn't supported yet and as such there is no need
8534 * to keep track of anything that isn't related to executable code:
8536 if (!(vma->vm_flags & VM_EXEC))
8540 for_each_task_context_nr(ctxn) {
8541 ctx = rcu_dereference(current->perf_event_ctxp[ctxn]);
8545 perf_iterate_ctx(ctx, __perf_addr_filters_adjust, vma, true);
8550 void perf_event_mmap(struct vm_area_struct *vma)
8552 struct perf_mmap_event mmap_event;
8554 if (!atomic_read(&nr_mmap_events))
8557 mmap_event = (struct perf_mmap_event){
8563 .type = PERF_RECORD_MMAP,
8564 .misc = PERF_RECORD_MISC_USER,
8569 .start = vma->vm_start,
8570 .len = vma->vm_end - vma->vm_start,
8571 .pgoff = (u64)vma->vm_pgoff << PAGE_SHIFT,
8573 /* .maj (attr_mmap2 only) */
8574 /* .min (attr_mmap2 only) */
8575 /* .ino (attr_mmap2 only) */
8576 /* .ino_generation (attr_mmap2 only) */
8577 /* .prot (attr_mmap2 only) */
8578 /* .flags (attr_mmap2 only) */
8581 perf_addr_filters_adjust(vma);
8582 perf_event_mmap_event(&mmap_event);
8585 void perf_event_aux_event(struct perf_event *event, unsigned long head,
8586 unsigned long size, u64 flags)
8588 struct perf_output_handle handle;
8589 struct perf_sample_data sample;
8590 struct perf_aux_event {
8591 struct perf_event_header header;
8597 .type = PERF_RECORD_AUX,
8599 .size = sizeof(rec),
8607 perf_event_header__init_id(&rec.header, &sample, event);
8608 ret = perf_output_begin(&handle, &sample, event, rec.header.size);
8613 perf_output_put(&handle, rec);
8614 perf_event__output_id_sample(event, &handle, &sample);
8616 perf_output_end(&handle);
8620 * Lost/dropped samples logging
8622 void perf_log_lost_samples(struct perf_event *event, u64 lost)
8624 struct perf_output_handle handle;
8625 struct perf_sample_data sample;
8629 struct perf_event_header header;
8631 } lost_samples_event = {
8633 .type = PERF_RECORD_LOST_SAMPLES,
8635 .size = sizeof(lost_samples_event),
8640 perf_event_header__init_id(&lost_samples_event.header, &sample, event);
8642 ret = perf_output_begin(&handle, &sample, event,
8643 lost_samples_event.header.size);
8647 perf_output_put(&handle, lost_samples_event);
8648 perf_event__output_id_sample(event, &handle, &sample);
8649 perf_output_end(&handle);
8653 * context_switch tracking
8656 struct perf_switch_event {
8657 struct task_struct *task;
8658 struct task_struct *next_prev;
8661 struct perf_event_header header;
8667 static int perf_event_switch_match(struct perf_event *event)
8669 return event->attr.context_switch;
8672 static void perf_event_switch_output(struct perf_event *event, void *data)
8674 struct perf_switch_event *se = data;
8675 struct perf_output_handle handle;
8676 struct perf_sample_data sample;
8679 if (!perf_event_switch_match(event))
8682 /* Only CPU-wide events are allowed to see next/prev pid/tid */
8683 if (event->ctx->task) {
8684 se->event_id.header.type = PERF_RECORD_SWITCH;
8685 se->event_id.header.size = sizeof(se->event_id.header);
8687 se->event_id.header.type = PERF_RECORD_SWITCH_CPU_WIDE;
8688 se->event_id.header.size = sizeof(se->event_id);
8689 se->event_id.next_prev_pid =
8690 perf_event_pid(event, se->next_prev);
8691 se->event_id.next_prev_tid =
8692 perf_event_tid(event, se->next_prev);
8695 perf_event_header__init_id(&se->event_id.header, &sample, event);
8697 ret = perf_output_begin(&handle, &sample, event, se->event_id.header.size);
8701 if (event->ctx->task)
8702 perf_output_put(&handle, se->event_id.header);
8704 perf_output_put(&handle, se->event_id);
8706 perf_event__output_id_sample(event, &handle, &sample);
8708 perf_output_end(&handle);
8711 static void perf_event_switch(struct task_struct *task,
8712 struct task_struct *next_prev, bool sched_in)
8714 struct perf_switch_event switch_event;
8716 /* N.B. caller checks nr_switch_events != 0 */
8718 switch_event = (struct perf_switch_event){
8720 .next_prev = next_prev,
8724 .misc = sched_in ? 0 : PERF_RECORD_MISC_SWITCH_OUT,
8727 /* .next_prev_pid */
8728 /* .next_prev_tid */
8732 if (!sched_in && task->on_rq) {
8733 switch_event.event_id.header.misc |=
8734 PERF_RECORD_MISC_SWITCH_OUT_PREEMPT;
8737 perf_iterate_sb(perf_event_switch_output, &switch_event, NULL);
8741 * IRQ throttle logging
8744 static void perf_log_throttle(struct perf_event *event, int enable)
8746 struct perf_output_handle handle;
8747 struct perf_sample_data sample;
8751 struct perf_event_header header;
8755 } throttle_event = {
8757 .type = PERF_RECORD_THROTTLE,
8759 .size = sizeof(throttle_event),
8761 .time = perf_event_clock(event),
8762 .id = primary_event_id(event),
8763 .stream_id = event->id,
8767 throttle_event.header.type = PERF_RECORD_UNTHROTTLE;
8769 perf_event_header__init_id(&throttle_event.header, &sample, event);
8771 ret = perf_output_begin(&handle, &sample, event,
8772 throttle_event.header.size);
8776 perf_output_put(&handle, throttle_event);
8777 perf_event__output_id_sample(event, &handle, &sample);
8778 perf_output_end(&handle);
8782 * ksymbol register/unregister tracking
8785 struct perf_ksymbol_event {
8789 struct perf_event_header header;
8797 static int perf_event_ksymbol_match(struct perf_event *event)
8799 return event->attr.ksymbol;
8802 static void perf_event_ksymbol_output(struct perf_event *event, void *data)
8804 struct perf_ksymbol_event *ksymbol_event = data;
8805 struct perf_output_handle handle;
8806 struct perf_sample_data sample;
8809 if (!perf_event_ksymbol_match(event))
8812 perf_event_header__init_id(&ksymbol_event->event_id.header,
8814 ret = perf_output_begin(&handle, &sample, event,
8815 ksymbol_event->event_id.header.size);
8819 perf_output_put(&handle, ksymbol_event->event_id);
8820 __output_copy(&handle, ksymbol_event->name, ksymbol_event->name_len);
8821 perf_event__output_id_sample(event, &handle, &sample);
8823 perf_output_end(&handle);
8826 void perf_event_ksymbol(u16 ksym_type, u64 addr, u32 len, bool unregister,
8829 struct perf_ksymbol_event ksymbol_event;
8830 char name[KSYM_NAME_LEN];
8834 if (!atomic_read(&nr_ksymbol_events))
8837 if (ksym_type >= PERF_RECORD_KSYMBOL_TYPE_MAX ||
8838 ksym_type == PERF_RECORD_KSYMBOL_TYPE_UNKNOWN)
8841 strlcpy(name, sym, KSYM_NAME_LEN);
8842 name_len = strlen(name) + 1;
8843 while (!IS_ALIGNED(name_len, sizeof(u64)))
8844 name[name_len++] = '\0';
8845 BUILD_BUG_ON(KSYM_NAME_LEN % sizeof(u64));
8848 flags |= PERF_RECORD_KSYMBOL_FLAGS_UNREGISTER;
8850 ksymbol_event = (struct perf_ksymbol_event){
8852 .name_len = name_len,
8855 .type = PERF_RECORD_KSYMBOL,
8856 .size = sizeof(ksymbol_event.event_id) +
8861 .ksym_type = ksym_type,
8866 perf_iterate_sb(perf_event_ksymbol_output, &ksymbol_event, NULL);
8869 WARN_ONCE(1, "%s: Invalid KSYMBOL type 0x%x\n", __func__, ksym_type);
8873 * bpf program load/unload tracking
8876 struct perf_bpf_event {
8877 struct bpf_prog *prog;
8879 struct perf_event_header header;
8883 u8 tag[BPF_TAG_SIZE];
8887 static int perf_event_bpf_match(struct perf_event *event)
8889 return event->attr.bpf_event;
8892 static void perf_event_bpf_output(struct perf_event *event, void *data)
8894 struct perf_bpf_event *bpf_event = data;
8895 struct perf_output_handle handle;
8896 struct perf_sample_data sample;
8899 if (!perf_event_bpf_match(event))
8902 perf_event_header__init_id(&bpf_event->event_id.header,
8904 ret = perf_output_begin(&handle, data, event,
8905 bpf_event->event_id.header.size);
8909 perf_output_put(&handle, bpf_event->event_id);
8910 perf_event__output_id_sample(event, &handle, &sample);
8912 perf_output_end(&handle);
8915 static void perf_event_bpf_emit_ksymbols(struct bpf_prog *prog,
8916 enum perf_bpf_event_type type)
8918 bool unregister = type == PERF_BPF_EVENT_PROG_UNLOAD;
8921 if (prog->aux->func_cnt == 0) {
8922 perf_event_ksymbol(PERF_RECORD_KSYMBOL_TYPE_BPF,
8923 (u64)(unsigned long)prog->bpf_func,
8924 prog->jited_len, unregister,
8925 prog->aux->ksym.name);
8927 for (i = 0; i < prog->aux->func_cnt; i++) {
8928 struct bpf_prog *subprog = prog->aux->func[i];
8931 PERF_RECORD_KSYMBOL_TYPE_BPF,
8932 (u64)(unsigned long)subprog->bpf_func,
8933 subprog->jited_len, unregister,
8934 prog->aux->ksym.name);
8939 void perf_event_bpf_event(struct bpf_prog *prog,
8940 enum perf_bpf_event_type type,
8943 struct perf_bpf_event bpf_event;
8945 if (type <= PERF_BPF_EVENT_UNKNOWN ||
8946 type >= PERF_BPF_EVENT_MAX)
8950 case PERF_BPF_EVENT_PROG_LOAD:
8951 case PERF_BPF_EVENT_PROG_UNLOAD:
8952 if (atomic_read(&nr_ksymbol_events))
8953 perf_event_bpf_emit_ksymbols(prog, type);
8959 if (!atomic_read(&nr_bpf_events))
8962 bpf_event = (struct perf_bpf_event){
8966 .type = PERF_RECORD_BPF_EVENT,
8967 .size = sizeof(bpf_event.event_id),
8971 .id = prog->aux->id,
8975 BUILD_BUG_ON(BPF_TAG_SIZE % sizeof(u64));
8977 memcpy(bpf_event.event_id.tag, prog->tag, BPF_TAG_SIZE);
8978 perf_iterate_sb(perf_event_bpf_output, &bpf_event, NULL);
8981 struct perf_text_poke_event {
8982 const void *old_bytes;
8983 const void *new_bytes;
8989 struct perf_event_header header;
8995 static int perf_event_text_poke_match(struct perf_event *event)
8997 return event->attr.text_poke;
9000 static void perf_event_text_poke_output(struct perf_event *event, void *data)
9002 struct perf_text_poke_event *text_poke_event = data;
9003 struct perf_output_handle handle;
9004 struct perf_sample_data sample;
9008 if (!perf_event_text_poke_match(event))
9011 perf_event_header__init_id(&text_poke_event->event_id.header, &sample, event);
9013 ret = perf_output_begin(&handle, &sample, event,
9014 text_poke_event->event_id.header.size);
9018 perf_output_put(&handle, text_poke_event->event_id);
9019 perf_output_put(&handle, text_poke_event->old_len);
9020 perf_output_put(&handle, text_poke_event->new_len);
9022 __output_copy(&handle, text_poke_event->old_bytes, text_poke_event->old_len);
9023 __output_copy(&handle, text_poke_event->new_bytes, text_poke_event->new_len);
9025 if (text_poke_event->pad)
9026 __output_copy(&handle, &padding, text_poke_event->pad);
9028 perf_event__output_id_sample(event, &handle, &sample);
9030 perf_output_end(&handle);
9033 void perf_event_text_poke(const void *addr, const void *old_bytes,
9034 size_t old_len, const void *new_bytes, size_t new_len)
9036 struct perf_text_poke_event text_poke_event;
9039 if (!atomic_read(&nr_text_poke_events))
9042 tot = sizeof(text_poke_event.old_len) + old_len;
9043 tot += sizeof(text_poke_event.new_len) + new_len;
9044 pad = ALIGN(tot, sizeof(u64)) - tot;
9046 text_poke_event = (struct perf_text_poke_event){
9047 .old_bytes = old_bytes,
9048 .new_bytes = new_bytes,
9054 .type = PERF_RECORD_TEXT_POKE,
9055 .misc = PERF_RECORD_MISC_KERNEL,
9056 .size = sizeof(text_poke_event.event_id) + tot + pad,
9058 .addr = (unsigned long)addr,
9062 perf_iterate_sb(perf_event_text_poke_output, &text_poke_event, NULL);
9065 void perf_event_itrace_started(struct perf_event *event)
9067 event->attach_state |= PERF_ATTACH_ITRACE;
9070 static void perf_log_itrace_start(struct perf_event *event)
9072 struct perf_output_handle handle;
9073 struct perf_sample_data sample;
9074 struct perf_aux_event {
9075 struct perf_event_header header;
9082 event = event->parent;
9084 if (!(event->pmu->capabilities & PERF_PMU_CAP_ITRACE) ||
9085 event->attach_state & PERF_ATTACH_ITRACE)
9088 rec.header.type = PERF_RECORD_ITRACE_START;
9089 rec.header.misc = 0;
9090 rec.header.size = sizeof(rec);
9091 rec.pid = perf_event_pid(event, current);
9092 rec.tid = perf_event_tid(event, current);
9094 perf_event_header__init_id(&rec.header, &sample, event);
9095 ret = perf_output_begin(&handle, &sample, event, rec.header.size);
9100 perf_output_put(&handle, rec);
9101 perf_event__output_id_sample(event, &handle, &sample);
9103 perf_output_end(&handle);
9106 void perf_report_aux_output_id(struct perf_event *event, u64 hw_id)
9108 struct perf_output_handle handle;
9109 struct perf_sample_data sample;
9110 struct perf_aux_event {
9111 struct perf_event_header header;
9117 event = event->parent;
9119 rec.header.type = PERF_RECORD_AUX_OUTPUT_HW_ID;
9120 rec.header.misc = 0;
9121 rec.header.size = sizeof(rec);
9124 perf_event_header__init_id(&rec.header, &sample, event);
9125 ret = perf_output_begin(&handle, &sample, event, rec.header.size);
9130 perf_output_put(&handle, rec);
9131 perf_event__output_id_sample(event, &handle, &sample);
9133 perf_output_end(&handle);
9137 __perf_event_account_interrupt(struct perf_event *event, int throttle)
9139 struct hw_perf_event *hwc = &event->hw;
9143 seq = __this_cpu_read(perf_throttled_seq);
9144 if (seq != hwc->interrupts_seq) {
9145 hwc->interrupts_seq = seq;
9146 hwc->interrupts = 1;
9149 if (unlikely(throttle
9150 && hwc->interrupts >= max_samples_per_tick)) {
9151 __this_cpu_inc(perf_throttled_count);
9152 tick_dep_set_cpu(smp_processor_id(), TICK_DEP_BIT_PERF_EVENTS);
9153 hwc->interrupts = MAX_INTERRUPTS;
9154 perf_log_throttle(event, 0);
9159 if (event->attr.freq) {
9160 u64 now = perf_clock();
9161 s64 delta = now - hwc->freq_time_stamp;
9163 hwc->freq_time_stamp = now;
9165 if (delta > 0 && delta < 2*TICK_NSEC)
9166 perf_adjust_period(event, delta, hwc->last_period, true);
9172 int perf_event_account_interrupt(struct perf_event *event)
9174 return __perf_event_account_interrupt(event, 1);
9178 * Generic event overflow handling, sampling.
9181 static int __perf_event_overflow(struct perf_event *event,
9182 int throttle, struct perf_sample_data *data,
9183 struct pt_regs *regs)
9185 int events = atomic_read(&event->event_limit);
9189 * Non-sampling counters might still use the PMI to fold short
9190 * hardware counters, ignore those.
9192 if (unlikely(!is_sampling_event(event)))
9195 ret = __perf_event_account_interrupt(event, throttle);
9198 * XXX event_limit might not quite work as expected on inherited
9202 event->pending_kill = POLL_IN;
9203 if (events && atomic_dec_and_test(&event->event_limit)) {
9205 event->pending_kill = POLL_HUP;
9206 event->pending_addr = data->addr;
9208 perf_event_disable_inatomic(event);
9211 READ_ONCE(event->overflow_handler)(event, data, regs);
9213 if (*perf_event_fasync(event) && event->pending_kill) {
9214 event->pending_wakeup = 1;
9215 irq_work_queue(&event->pending);
9221 int perf_event_overflow(struct perf_event *event,
9222 struct perf_sample_data *data,
9223 struct pt_regs *regs)
9225 return __perf_event_overflow(event, 1, data, regs);
9229 * Generic software event infrastructure
9232 struct swevent_htable {
9233 struct swevent_hlist *swevent_hlist;
9234 struct mutex hlist_mutex;
9237 /* Recursion avoidance in each contexts */
9238 int recursion[PERF_NR_CONTEXTS];
9241 static DEFINE_PER_CPU(struct swevent_htable, swevent_htable);
9244 * We directly increment event->count and keep a second value in
9245 * event->hw.period_left to count intervals. This period event
9246 * is kept in the range [-sample_period, 0] so that we can use the
9250 u64 perf_swevent_set_period(struct perf_event *event)
9252 struct hw_perf_event *hwc = &event->hw;
9253 u64 period = hwc->last_period;
9257 hwc->last_period = hwc->sample_period;
9260 old = val = local64_read(&hwc->period_left);
9264 nr = div64_u64(period + val, period);
9265 offset = nr * period;
9267 if (local64_cmpxchg(&hwc->period_left, old, val) != old)
9273 static void perf_swevent_overflow(struct perf_event *event, u64 overflow,
9274 struct perf_sample_data *data,
9275 struct pt_regs *regs)
9277 struct hw_perf_event *hwc = &event->hw;
9281 overflow = perf_swevent_set_period(event);
9283 if (hwc->interrupts == MAX_INTERRUPTS)
9286 for (; overflow; overflow--) {
9287 if (__perf_event_overflow(event, throttle,
9290 * We inhibit the overflow from happening when
9291 * hwc->interrupts == MAX_INTERRUPTS.
9299 static void perf_swevent_event(struct perf_event *event, u64 nr,
9300 struct perf_sample_data *data,
9301 struct pt_regs *regs)
9303 struct hw_perf_event *hwc = &event->hw;
9305 local64_add(nr, &event->count);
9310 if (!is_sampling_event(event))
9313 if ((event->attr.sample_type & PERF_SAMPLE_PERIOD) && !event->attr.freq) {
9315 return perf_swevent_overflow(event, 1, data, regs);
9317 data->period = event->hw.last_period;
9319 if (nr == 1 && hwc->sample_period == 1 && !event->attr.freq)
9320 return perf_swevent_overflow(event, 1, data, regs);
9322 if (local64_add_negative(nr, &hwc->period_left))
9325 perf_swevent_overflow(event, 0, data, regs);
9328 static int perf_exclude_event(struct perf_event *event,
9329 struct pt_regs *regs)
9331 if (event->hw.state & PERF_HES_STOPPED)
9335 if (event->attr.exclude_user && user_mode(regs))
9338 if (event->attr.exclude_kernel && !user_mode(regs))
9345 static int perf_swevent_match(struct perf_event *event,
9346 enum perf_type_id type,
9348 struct perf_sample_data *data,
9349 struct pt_regs *regs)
9351 if (event->attr.type != type)
9354 if (event->attr.config != event_id)
9357 if (perf_exclude_event(event, regs))
9363 static inline u64 swevent_hash(u64 type, u32 event_id)
9365 u64 val = event_id | (type << 32);
9367 return hash_64(val, SWEVENT_HLIST_BITS);
9370 static inline struct hlist_head *
9371 __find_swevent_head(struct swevent_hlist *hlist, u64 type, u32 event_id)
9373 u64 hash = swevent_hash(type, event_id);
9375 return &hlist->heads[hash];
9378 /* For the read side: events when they trigger */
9379 static inline struct hlist_head *
9380 find_swevent_head_rcu(struct swevent_htable *swhash, u64 type, u32 event_id)
9382 struct swevent_hlist *hlist;
9384 hlist = rcu_dereference(swhash->swevent_hlist);
9388 return __find_swevent_head(hlist, type, event_id);
9391 /* For the event head insertion and removal in the hlist */
9392 static inline struct hlist_head *
9393 find_swevent_head(struct swevent_htable *swhash, struct perf_event *event)
9395 struct swevent_hlist *hlist;
9396 u32 event_id = event->attr.config;
9397 u64 type = event->attr.type;
9400 * Event scheduling is always serialized against hlist allocation
9401 * and release. Which makes the protected version suitable here.
9402 * The context lock guarantees that.
9404 hlist = rcu_dereference_protected(swhash->swevent_hlist,
9405 lockdep_is_held(&event->ctx->lock));
9409 return __find_swevent_head(hlist, type, event_id);
9412 static void do_perf_sw_event(enum perf_type_id type, u32 event_id,
9414 struct perf_sample_data *data,
9415 struct pt_regs *regs)
9417 struct swevent_htable *swhash = this_cpu_ptr(&swevent_htable);
9418 struct perf_event *event;
9419 struct hlist_head *head;
9422 head = find_swevent_head_rcu(swhash, type, event_id);
9426 hlist_for_each_entry_rcu(event, head, hlist_entry) {
9427 if (perf_swevent_match(event, type, event_id, data, regs))
9428 perf_swevent_event(event, nr, data, regs);
9434 DEFINE_PER_CPU(struct pt_regs, __perf_regs[4]);
9436 int perf_swevent_get_recursion_context(void)
9438 struct swevent_htable *swhash = this_cpu_ptr(&swevent_htable);
9440 return get_recursion_context(swhash->recursion);
9442 EXPORT_SYMBOL_GPL(perf_swevent_get_recursion_context);
9444 void perf_swevent_put_recursion_context(int rctx)
9446 struct swevent_htable *swhash = this_cpu_ptr(&swevent_htable);
9448 put_recursion_context(swhash->recursion, rctx);
9451 void ___perf_sw_event(u32 event_id, u64 nr, struct pt_regs *regs, u64 addr)
9453 struct perf_sample_data data;
9455 if (WARN_ON_ONCE(!regs))
9458 perf_sample_data_init(&data, addr, 0);
9459 do_perf_sw_event(PERF_TYPE_SOFTWARE, event_id, nr, &data, regs);
9462 void __perf_sw_event(u32 event_id, u64 nr, struct pt_regs *regs, u64 addr)
9466 preempt_disable_notrace();
9467 rctx = perf_swevent_get_recursion_context();
9468 if (unlikely(rctx < 0))
9471 ___perf_sw_event(event_id, nr, regs, addr);
9473 perf_swevent_put_recursion_context(rctx);
9475 preempt_enable_notrace();
9478 static void perf_swevent_read(struct perf_event *event)
9482 static int perf_swevent_add(struct perf_event *event, int flags)
9484 struct swevent_htable *swhash = this_cpu_ptr(&swevent_htable);
9485 struct hw_perf_event *hwc = &event->hw;
9486 struct hlist_head *head;
9488 if (is_sampling_event(event)) {
9489 hwc->last_period = hwc->sample_period;
9490 perf_swevent_set_period(event);
9493 hwc->state = !(flags & PERF_EF_START);
9495 head = find_swevent_head(swhash, event);
9496 if (WARN_ON_ONCE(!head))
9499 hlist_add_head_rcu(&event->hlist_entry, head);
9500 perf_event_update_userpage(event);
9505 static void perf_swevent_del(struct perf_event *event, int flags)
9507 hlist_del_rcu(&event->hlist_entry);
9510 static void perf_swevent_start(struct perf_event *event, int flags)
9512 event->hw.state = 0;
9515 static void perf_swevent_stop(struct perf_event *event, int flags)
9517 event->hw.state = PERF_HES_STOPPED;
9520 /* Deref the hlist from the update side */
9521 static inline struct swevent_hlist *
9522 swevent_hlist_deref(struct swevent_htable *swhash)
9524 return rcu_dereference_protected(swhash->swevent_hlist,
9525 lockdep_is_held(&swhash->hlist_mutex));
9528 static void swevent_hlist_release(struct swevent_htable *swhash)
9530 struct swevent_hlist *hlist = swevent_hlist_deref(swhash);
9535 RCU_INIT_POINTER(swhash->swevent_hlist, NULL);
9536 kfree_rcu(hlist, rcu_head);
9539 static void swevent_hlist_put_cpu(int cpu)
9541 struct swevent_htable *swhash = &per_cpu(swevent_htable, cpu);
9543 mutex_lock(&swhash->hlist_mutex);
9545 if (!--swhash->hlist_refcount)
9546 swevent_hlist_release(swhash);
9548 mutex_unlock(&swhash->hlist_mutex);
9551 static void swevent_hlist_put(void)
9555 for_each_possible_cpu(cpu)
9556 swevent_hlist_put_cpu(cpu);
9559 static int swevent_hlist_get_cpu(int cpu)
9561 struct swevent_htable *swhash = &per_cpu(swevent_htable, cpu);
9564 mutex_lock(&swhash->hlist_mutex);
9565 if (!swevent_hlist_deref(swhash) &&
9566 cpumask_test_cpu(cpu, perf_online_mask)) {
9567 struct swevent_hlist *hlist;
9569 hlist = kzalloc(sizeof(*hlist), GFP_KERNEL);
9574 rcu_assign_pointer(swhash->swevent_hlist, hlist);
9576 swhash->hlist_refcount++;
9578 mutex_unlock(&swhash->hlist_mutex);
9583 static int swevent_hlist_get(void)
9585 int err, cpu, failed_cpu;
9587 mutex_lock(&pmus_lock);
9588 for_each_possible_cpu(cpu) {
9589 err = swevent_hlist_get_cpu(cpu);
9595 mutex_unlock(&pmus_lock);
9598 for_each_possible_cpu(cpu) {
9599 if (cpu == failed_cpu)
9601 swevent_hlist_put_cpu(cpu);
9603 mutex_unlock(&pmus_lock);
9607 struct static_key perf_swevent_enabled[PERF_COUNT_SW_MAX];
9609 static void sw_perf_event_destroy(struct perf_event *event)
9611 u64 event_id = event->attr.config;
9613 WARN_ON(event->parent);
9615 static_key_slow_dec(&perf_swevent_enabled[event_id]);
9616 swevent_hlist_put();
9619 static int perf_swevent_init(struct perf_event *event)
9621 u64 event_id = event->attr.config;
9623 if (event->attr.type != PERF_TYPE_SOFTWARE)
9627 * no branch sampling for software events
9629 if (has_branch_stack(event))
9633 case PERF_COUNT_SW_CPU_CLOCK:
9634 case PERF_COUNT_SW_TASK_CLOCK:
9641 if (event_id >= PERF_COUNT_SW_MAX)
9644 if (!event->parent) {
9647 err = swevent_hlist_get();
9651 static_key_slow_inc(&perf_swevent_enabled[event_id]);
9652 event->destroy = sw_perf_event_destroy;
9658 static struct pmu perf_swevent = {
9659 .task_ctx_nr = perf_sw_context,
9661 .capabilities = PERF_PMU_CAP_NO_NMI,
9663 .event_init = perf_swevent_init,
9664 .add = perf_swevent_add,
9665 .del = perf_swevent_del,
9666 .start = perf_swevent_start,
9667 .stop = perf_swevent_stop,
9668 .read = perf_swevent_read,
9671 #ifdef CONFIG_EVENT_TRACING
9673 static int perf_tp_filter_match(struct perf_event *event,
9674 struct perf_sample_data *data)
9676 void *record = data->raw->frag.data;
9678 /* only top level events have filters set */
9680 event = event->parent;
9682 if (likely(!event->filter) || filter_match_preds(event->filter, record))
9687 static int perf_tp_event_match(struct perf_event *event,
9688 struct perf_sample_data *data,
9689 struct pt_regs *regs)
9691 if (event->hw.state & PERF_HES_STOPPED)
9694 * If exclude_kernel, only trace user-space tracepoints (uprobes)
9696 if (event->attr.exclude_kernel && !user_mode(regs))
9699 if (!perf_tp_filter_match(event, data))
9705 void perf_trace_run_bpf_submit(void *raw_data, int size, int rctx,
9706 struct trace_event_call *call, u64 count,
9707 struct pt_regs *regs, struct hlist_head *head,
9708 struct task_struct *task)
9710 if (bpf_prog_array_valid(call)) {
9711 *(struct pt_regs **)raw_data = regs;
9712 if (!trace_call_bpf(call, raw_data) || hlist_empty(head)) {
9713 perf_swevent_put_recursion_context(rctx);
9717 perf_tp_event(call->event.type, count, raw_data, size, regs, head,
9720 EXPORT_SYMBOL_GPL(perf_trace_run_bpf_submit);
9722 void perf_tp_event(u16 event_type, u64 count, void *record, int entry_size,
9723 struct pt_regs *regs, struct hlist_head *head, int rctx,
9724 struct task_struct *task)
9726 struct perf_sample_data data;
9727 struct perf_event *event;
9729 struct perf_raw_record raw = {
9736 perf_sample_data_init(&data, 0, 0);
9739 perf_trace_buf_update(record, event_type);
9741 hlist_for_each_entry_rcu(event, head, hlist_entry) {
9742 if (perf_tp_event_match(event, &data, regs))
9743 perf_swevent_event(event, count, &data, regs);
9747 * If we got specified a target task, also iterate its context and
9748 * deliver this event there too.
9750 if (task && task != current) {
9751 struct perf_event_context *ctx;
9752 struct trace_entry *entry = record;
9755 ctx = rcu_dereference(task->perf_event_ctxp[perf_sw_context]);
9759 list_for_each_entry_rcu(event, &ctx->event_list, event_entry) {
9760 if (event->cpu != smp_processor_id())
9762 if (event->attr.type != PERF_TYPE_TRACEPOINT)
9764 if (event->attr.config != entry->type)
9766 /* Cannot deliver synchronous signal to other task. */
9767 if (event->attr.sigtrap)
9769 if (perf_tp_event_match(event, &data, regs))
9770 perf_swevent_event(event, count, &data, regs);
9776 perf_swevent_put_recursion_context(rctx);
9778 EXPORT_SYMBOL_GPL(perf_tp_event);
9780 static void tp_perf_event_destroy(struct perf_event *event)
9782 perf_trace_destroy(event);
9785 static int perf_tp_event_init(struct perf_event *event)
9789 if (event->attr.type != PERF_TYPE_TRACEPOINT)
9793 * no branch sampling for tracepoint events
9795 if (has_branch_stack(event))
9798 err = perf_trace_init(event);
9802 event->destroy = tp_perf_event_destroy;
9807 static struct pmu perf_tracepoint = {
9808 .task_ctx_nr = perf_sw_context,
9810 .event_init = perf_tp_event_init,
9811 .add = perf_trace_add,
9812 .del = perf_trace_del,
9813 .start = perf_swevent_start,
9814 .stop = perf_swevent_stop,
9815 .read = perf_swevent_read,
9818 #if defined(CONFIG_KPROBE_EVENTS) || defined(CONFIG_UPROBE_EVENTS)
9820 * Flags in config, used by dynamic PMU kprobe and uprobe
9821 * The flags should match following PMU_FORMAT_ATTR().
9823 * PERF_PROBE_CONFIG_IS_RETPROBE if set, create kretprobe/uretprobe
9824 * if not set, create kprobe/uprobe
9826 * The following values specify a reference counter (or semaphore in the
9827 * terminology of tools like dtrace, systemtap, etc.) Userspace Statically
9828 * Defined Tracepoints (USDT). Currently, we use 40 bit for the offset.
9830 * PERF_UPROBE_REF_CTR_OFFSET_BITS # of bits in config as th offset
9831 * PERF_UPROBE_REF_CTR_OFFSET_SHIFT # of bits to shift left
9833 enum perf_probe_config {
9834 PERF_PROBE_CONFIG_IS_RETPROBE = 1U << 0, /* [k,u]retprobe */
9835 PERF_UPROBE_REF_CTR_OFFSET_BITS = 32,
9836 PERF_UPROBE_REF_CTR_OFFSET_SHIFT = 64 - PERF_UPROBE_REF_CTR_OFFSET_BITS,
9839 PMU_FORMAT_ATTR(retprobe, "config:0");
9842 #ifdef CONFIG_KPROBE_EVENTS
9843 static struct attribute *kprobe_attrs[] = {
9844 &format_attr_retprobe.attr,
9848 static struct attribute_group kprobe_format_group = {
9850 .attrs = kprobe_attrs,
9853 static const struct attribute_group *kprobe_attr_groups[] = {
9854 &kprobe_format_group,
9858 static int perf_kprobe_event_init(struct perf_event *event);
9859 static struct pmu perf_kprobe = {
9860 .task_ctx_nr = perf_sw_context,
9861 .event_init = perf_kprobe_event_init,
9862 .add = perf_trace_add,
9863 .del = perf_trace_del,
9864 .start = perf_swevent_start,
9865 .stop = perf_swevent_stop,
9866 .read = perf_swevent_read,
9867 .attr_groups = kprobe_attr_groups,
9870 static int perf_kprobe_event_init(struct perf_event *event)
9875 if (event->attr.type != perf_kprobe.type)
9878 if (!perfmon_capable())
9882 * no branch sampling for probe events
9884 if (has_branch_stack(event))
9887 is_retprobe = event->attr.config & PERF_PROBE_CONFIG_IS_RETPROBE;
9888 err = perf_kprobe_init(event, is_retprobe);
9892 event->destroy = perf_kprobe_destroy;
9896 #endif /* CONFIG_KPROBE_EVENTS */
9898 #ifdef CONFIG_UPROBE_EVENTS
9899 PMU_FORMAT_ATTR(ref_ctr_offset, "config:32-63");
9901 static struct attribute *uprobe_attrs[] = {
9902 &format_attr_retprobe.attr,
9903 &format_attr_ref_ctr_offset.attr,
9907 static struct attribute_group uprobe_format_group = {
9909 .attrs = uprobe_attrs,
9912 static const struct attribute_group *uprobe_attr_groups[] = {
9913 &uprobe_format_group,
9917 static int perf_uprobe_event_init(struct perf_event *event);
9918 static struct pmu perf_uprobe = {
9919 .task_ctx_nr = perf_sw_context,
9920 .event_init = perf_uprobe_event_init,
9921 .add = perf_trace_add,
9922 .del = perf_trace_del,
9923 .start = perf_swevent_start,
9924 .stop = perf_swevent_stop,
9925 .read = perf_swevent_read,
9926 .attr_groups = uprobe_attr_groups,
9929 static int perf_uprobe_event_init(struct perf_event *event)
9932 unsigned long ref_ctr_offset;
9935 if (event->attr.type != perf_uprobe.type)
9938 if (!perfmon_capable())
9942 * no branch sampling for probe events
9944 if (has_branch_stack(event))
9947 is_retprobe = event->attr.config & PERF_PROBE_CONFIG_IS_RETPROBE;
9948 ref_ctr_offset = event->attr.config >> PERF_UPROBE_REF_CTR_OFFSET_SHIFT;
9949 err = perf_uprobe_init(event, ref_ctr_offset, is_retprobe);
9953 event->destroy = perf_uprobe_destroy;
9957 #endif /* CONFIG_UPROBE_EVENTS */
9959 static inline void perf_tp_register(void)
9961 perf_pmu_register(&perf_tracepoint, "tracepoint", PERF_TYPE_TRACEPOINT);
9962 #ifdef CONFIG_KPROBE_EVENTS
9963 perf_pmu_register(&perf_kprobe, "kprobe", -1);
9965 #ifdef CONFIG_UPROBE_EVENTS
9966 perf_pmu_register(&perf_uprobe, "uprobe", -1);
9970 static void perf_event_free_filter(struct perf_event *event)
9972 ftrace_profile_free_filter(event);
9975 #ifdef CONFIG_BPF_SYSCALL
9976 static void bpf_overflow_handler(struct perf_event *event,
9977 struct perf_sample_data *data,
9978 struct pt_regs *regs)
9980 struct bpf_perf_event_data_kern ctx = {
9984 struct bpf_prog *prog;
9987 ctx.regs = perf_arch_bpf_user_pt_regs(regs);
9988 if (unlikely(__this_cpu_inc_return(bpf_prog_active) != 1))
9991 prog = READ_ONCE(event->prog);
9993 ret = bpf_prog_run(prog, &ctx);
9996 __this_cpu_dec(bpf_prog_active);
10000 event->orig_overflow_handler(event, data, regs);
10003 static int perf_event_set_bpf_handler(struct perf_event *event,
10004 struct bpf_prog *prog,
10007 if (event->overflow_handler_context)
10008 /* hw breakpoint or kernel counter */
10014 if (prog->type != BPF_PROG_TYPE_PERF_EVENT)
10017 if (event->attr.precise_ip &&
10018 prog->call_get_stack &&
10019 (!(event->attr.sample_type & __PERF_SAMPLE_CALLCHAIN_EARLY) ||
10020 event->attr.exclude_callchain_kernel ||
10021 event->attr.exclude_callchain_user)) {
10023 * On perf_event with precise_ip, calling bpf_get_stack()
10024 * may trigger unwinder warnings and occasional crashes.
10025 * bpf_get_[stack|stackid] works around this issue by using
10026 * callchain attached to perf_sample_data. If the
10027 * perf_event does not full (kernel and user) callchain
10028 * attached to perf_sample_data, do not allow attaching BPF
10029 * program that calls bpf_get_[stack|stackid].
10034 event->prog = prog;
10035 event->bpf_cookie = bpf_cookie;
10036 event->orig_overflow_handler = READ_ONCE(event->overflow_handler);
10037 WRITE_ONCE(event->overflow_handler, bpf_overflow_handler);
10041 static void perf_event_free_bpf_handler(struct perf_event *event)
10043 struct bpf_prog *prog = event->prog;
10048 WRITE_ONCE(event->overflow_handler, event->orig_overflow_handler);
10049 event->prog = NULL;
10050 bpf_prog_put(prog);
10053 static int perf_event_set_bpf_handler(struct perf_event *event,
10054 struct bpf_prog *prog,
10057 return -EOPNOTSUPP;
10059 static void perf_event_free_bpf_handler(struct perf_event *event)
10065 * returns true if the event is a tracepoint, or a kprobe/upprobe created
10066 * with perf_event_open()
10068 static inline bool perf_event_is_tracing(struct perf_event *event)
10070 if (event->pmu == &perf_tracepoint)
10072 #ifdef CONFIG_KPROBE_EVENTS
10073 if (event->pmu == &perf_kprobe)
10076 #ifdef CONFIG_UPROBE_EVENTS
10077 if (event->pmu == &perf_uprobe)
10083 int perf_event_set_bpf_prog(struct perf_event *event, struct bpf_prog *prog,
10086 bool is_kprobe, is_tracepoint, is_syscall_tp;
10088 if (!perf_event_is_tracing(event))
10089 return perf_event_set_bpf_handler(event, prog, bpf_cookie);
10091 is_kprobe = event->tp_event->flags & TRACE_EVENT_FL_UKPROBE;
10092 is_tracepoint = event->tp_event->flags & TRACE_EVENT_FL_TRACEPOINT;
10093 is_syscall_tp = is_syscall_trace_event(event->tp_event);
10094 if (!is_kprobe && !is_tracepoint && !is_syscall_tp)
10095 /* bpf programs can only be attached to u/kprobe or tracepoint */
10098 if ((is_kprobe && prog->type != BPF_PROG_TYPE_KPROBE) ||
10099 (is_tracepoint && prog->type != BPF_PROG_TYPE_TRACEPOINT) ||
10100 (is_syscall_tp && prog->type != BPF_PROG_TYPE_TRACEPOINT))
10103 /* Kprobe override only works for kprobes, not uprobes. */
10104 if (prog->kprobe_override &&
10105 !(event->tp_event->flags & TRACE_EVENT_FL_KPROBE))
10108 if (is_tracepoint || is_syscall_tp) {
10109 int off = trace_event_get_offsets(event->tp_event);
10111 if (prog->aux->max_ctx_offset > off)
10115 return perf_event_attach_bpf_prog(event, prog, bpf_cookie);
10118 void perf_event_free_bpf_prog(struct perf_event *event)
10120 if (!perf_event_is_tracing(event)) {
10121 perf_event_free_bpf_handler(event);
10124 perf_event_detach_bpf_prog(event);
10129 static inline void perf_tp_register(void)
10133 static void perf_event_free_filter(struct perf_event *event)
10137 int perf_event_set_bpf_prog(struct perf_event *event, struct bpf_prog *prog,
10143 void perf_event_free_bpf_prog(struct perf_event *event)
10146 #endif /* CONFIG_EVENT_TRACING */
10148 #ifdef CONFIG_HAVE_HW_BREAKPOINT
10149 void perf_bp_event(struct perf_event *bp, void *data)
10151 struct perf_sample_data sample;
10152 struct pt_regs *regs = data;
10154 perf_sample_data_init(&sample, bp->attr.bp_addr, 0);
10156 if (!bp->hw.state && !perf_exclude_event(bp, regs))
10157 perf_swevent_event(bp, 1, &sample, regs);
10162 * Allocate a new address filter
10164 static struct perf_addr_filter *
10165 perf_addr_filter_new(struct perf_event *event, struct list_head *filters)
10167 int node = cpu_to_node(event->cpu == -1 ? 0 : event->cpu);
10168 struct perf_addr_filter *filter;
10170 filter = kzalloc_node(sizeof(*filter), GFP_KERNEL, node);
10174 INIT_LIST_HEAD(&filter->entry);
10175 list_add_tail(&filter->entry, filters);
10180 static void free_filters_list(struct list_head *filters)
10182 struct perf_addr_filter *filter, *iter;
10184 list_for_each_entry_safe(filter, iter, filters, entry) {
10185 path_put(&filter->path);
10186 list_del(&filter->entry);
10192 * Free existing address filters and optionally install new ones
10194 static void perf_addr_filters_splice(struct perf_event *event,
10195 struct list_head *head)
10197 unsigned long flags;
10200 if (!has_addr_filter(event))
10203 /* don't bother with children, they don't have their own filters */
10207 raw_spin_lock_irqsave(&event->addr_filters.lock, flags);
10209 list_splice_init(&event->addr_filters.list, &list);
10211 list_splice(head, &event->addr_filters.list);
10213 raw_spin_unlock_irqrestore(&event->addr_filters.lock, flags);
10215 free_filters_list(&list);
10219 * Scan through mm's vmas and see if one of them matches the
10220 * @filter; if so, adjust filter's address range.
10221 * Called with mm::mmap_lock down for reading.
10223 static void perf_addr_filter_apply(struct perf_addr_filter *filter,
10224 struct mm_struct *mm,
10225 struct perf_addr_filter_range *fr)
10227 struct vm_area_struct *vma;
10229 for (vma = mm->mmap; vma; vma = vma->vm_next) {
10233 if (perf_addr_filter_vma_adjust(filter, vma, fr))
10239 * Update event's address range filters based on the
10240 * task's existing mappings, if any.
10242 static void perf_event_addr_filters_apply(struct perf_event *event)
10244 struct perf_addr_filters_head *ifh = perf_event_addr_filters(event);
10245 struct task_struct *task = READ_ONCE(event->ctx->task);
10246 struct perf_addr_filter *filter;
10247 struct mm_struct *mm = NULL;
10248 unsigned int count = 0;
10249 unsigned long flags;
10252 * We may observe TASK_TOMBSTONE, which means that the event tear-down
10253 * will stop on the parent's child_mutex that our caller is also holding
10255 if (task == TASK_TOMBSTONE)
10258 if (ifh->nr_file_filters) {
10259 mm = get_task_mm(task);
10263 mmap_read_lock(mm);
10266 raw_spin_lock_irqsave(&ifh->lock, flags);
10267 list_for_each_entry(filter, &ifh->list, entry) {
10268 if (filter->path.dentry) {
10270 * Adjust base offset if the filter is associated to a
10271 * binary that needs to be mapped:
10273 event->addr_filter_ranges[count].start = 0;
10274 event->addr_filter_ranges[count].size = 0;
10276 perf_addr_filter_apply(filter, mm, &event->addr_filter_ranges[count]);
10278 event->addr_filter_ranges[count].start = filter->offset;
10279 event->addr_filter_ranges[count].size = filter->size;
10285 event->addr_filters_gen++;
10286 raw_spin_unlock_irqrestore(&ifh->lock, flags);
10288 if (ifh->nr_file_filters) {
10289 mmap_read_unlock(mm);
10295 perf_event_stop(event, 1);
10299 * Address range filtering: limiting the data to certain
10300 * instruction address ranges. Filters are ioctl()ed to us from
10301 * userspace as ascii strings.
10303 * Filter string format:
10305 * ACTION RANGE_SPEC
10306 * where ACTION is one of the
10307 * * "filter": limit the trace to this region
10308 * * "start": start tracing from this address
10309 * * "stop": stop tracing at this address/region;
10311 * * for kernel addresses: <start address>[/<size>]
10312 * * for object files: <start address>[/<size>]@</path/to/object/file>
10314 * if <size> is not specified or is zero, the range is treated as a single
10315 * address; not valid for ACTION=="filter".
10329 IF_STATE_ACTION = 0,
10334 static const match_table_t if_tokens = {
10335 { IF_ACT_FILTER, "filter" },
10336 { IF_ACT_START, "start" },
10337 { IF_ACT_STOP, "stop" },
10338 { IF_SRC_FILE, "%u/%u@%s" },
10339 { IF_SRC_KERNEL, "%u/%u" },
10340 { IF_SRC_FILEADDR, "%u@%s" },
10341 { IF_SRC_KERNELADDR, "%u" },
10342 { IF_ACT_NONE, NULL },
10346 * Address filter string parser
10349 perf_event_parse_addr_filter(struct perf_event *event, char *fstr,
10350 struct list_head *filters)
10352 struct perf_addr_filter *filter = NULL;
10353 char *start, *orig, *filename = NULL;
10354 substring_t args[MAX_OPT_ARGS];
10355 int state = IF_STATE_ACTION, token;
10356 unsigned int kernel = 0;
10359 orig = fstr = kstrdup(fstr, GFP_KERNEL);
10363 while ((start = strsep(&fstr, " ,\n")) != NULL) {
10364 static const enum perf_addr_filter_action_t actions[] = {
10365 [IF_ACT_FILTER] = PERF_ADDR_FILTER_ACTION_FILTER,
10366 [IF_ACT_START] = PERF_ADDR_FILTER_ACTION_START,
10367 [IF_ACT_STOP] = PERF_ADDR_FILTER_ACTION_STOP,
10374 /* filter definition begins */
10375 if (state == IF_STATE_ACTION) {
10376 filter = perf_addr_filter_new(event, filters);
10381 token = match_token(start, if_tokens, args);
10383 case IF_ACT_FILTER:
10386 if (state != IF_STATE_ACTION)
10389 filter->action = actions[token];
10390 state = IF_STATE_SOURCE;
10393 case IF_SRC_KERNELADDR:
10394 case IF_SRC_KERNEL:
10398 case IF_SRC_FILEADDR:
10400 if (state != IF_STATE_SOURCE)
10404 ret = kstrtoul(args[0].from, 0, &filter->offset);
10408 if (token == IF_SRC_KERNEL || token == IF_SRC_FILE) {
10410 ret = kstrtoul(args[1].from, 0, &filter->size);
10415 if (token == IF_SRC_FILE || token == IF_SRC_FILEADDR) {
10416 int fpos = token == IF_SRC_FILE ? 2 : 1;
10419 filename = match_strdup(&args[fpos]);
10426 state = IF_STATE_END;
10434 * Filter definition is fully parsed, validate and install it.
10435 * Make sure that it doesn't contradict itself or the event's
10438 if (state == IF_STATE_END) {
10442 * ACTION "filter" must have a non-zero length region
10445 if (filter->action == PERF_ADDR_FILTER_ACTION_FILTER &&
10454 * For now, we only support file-based filters
10455 * in per-task events; doing so for CPU-wide
10456 * events requires additional context switching
10457 * trickery, since same object code will be
10458 * mapped at different virtual addresses in
10459 * different processes.
10462 if (!event->ctx->task)
10465 /* look up the path and grab its inode */
10466 ret = kern_path(filename, LOOKUP_FOLLOW,
10472 if (!filter->path.dentry ||
10473 !S_ISREG(d_inode(filter->path.dentry)
10477 event->addr_filters.nr_file_filters++;
10480 /* ready to consume more filters */
10483 state = IF_STATE_ACTION;
10489 if (state != IF_STATE_ACTION)
10499 free_filters_list(filters);
10506 perf_event_set_addr_filter(struct perf_event *event, char *filter_str)
10508 LIST_HEAD(filters);
10512 * Since this is called in perf_ioctl() path, we're already holding
10515 lockdep_assert_held(&event->ctx->mutex);
10517 if (WARN_ON_ONCE(event->parent))
10520 ret = perf_event_parse_addr_filter(event, filter_str, &filters);
10522 goto fail_clear_files;
10524 ret = event->pmu->addr_filters_validate(&filters);
10526 goto fail_free_filters;
10528 /* remove existing filters, if any */
10529 perf_addr_filters_splice(event, &filters);
10531 /* install new filters */
10532 perf_event_for_each_child(event, perf_event_addr_filters_apply);
10537 free_filters_list(&filters);
10540 event->addr_filters.nr_file_filters = 0;
10545 static int perf_event_set_filter(struct perf_event *event, void __user *arg)
10550 filter_str = strndup_user(arg, PAGE_SIZE);
10551 if (IS_ERR(filter_str))
10552 return PTR_ERR(filter_str);
10554 #ifdef CONFIG_EVENT_TRACING
10555 if (perf_event_is_tracing(event)) {
10556 struct perf_event_context *ctx = event->ctx;
10559 * Beware, here be dragons!!
10561 * the tracepoint muck will deadlock against ctx->mutex, but
10562 * the tracepoint stuff does not actually need it. So
10563 * temporarily drop ctx->mutex. As per perf_event_ctx_lock() we
10564 * already have a reference on ctx.
10566 * This can result in event getting moved to a different ctx,
10567 * but that does not affect the tracepoint state.
10569 mutex_unlock(&ctx->mutex);
10570 ret = ftrace_profile_set_filter(event, event->attr.config, filter_str);
10571 mutex_lock(&ctx->mutex);
10574 if (has_addr_filter(event))
10575 ret = perf_event_set_addr_filter(event, filter_str);
10582 * hrtimer based swevent callback
10585 static enum hrtimer_restart perf_swevent_hrtimer(struct hrtimer *hrtimer)
10587 enum hrtimer_restart ret = HRTIMER_RESTART;
10588 struct perf_sample_data data;
10589 struct pt_regs *regs;
10590 struct perf_event *event;
10593 event = container_of(hrtimer, struct perf_event, hw.hrtimer);
10595 if (event->state != PERF_EVENT_STATE_ACTIVE)
10596 return HRTIMER_NORESTART;
10598 event->pmu->read(event);
10600 perf_sample_data_init(&data, 0, event->hw.last_period);
10601 regs = get_irq_regs();
10603 if (regs && !perf_exclude_event(event, regs)) {
10604 if (!(event->attr.exclude_idle && is_idle_task(current)))
10605 if (__perf_event_overflow(event, 1, &data, regs))
10606 ret = HRTIMER_NORESTART;
10609 period = max_t(u64, 10000, event->hw.sample_period);
10610 hrtimer_forward_now(hrtimer, ns_to_ktime(period));
10615 static void perf_swevent_start_hrtimer(struct perf_event *event)
10617 struct hw_perf_event *hwc = &event->hw;
10620 if (!is_sampling_event(event))
10623 period = local64_read(&hwc->period_left);
10628 local64_set(&hwc->period_left, 0);
10630 period = max_t(u64, 10000, hwc->sample_period);
10632 hrtimer_start(&hwc->hrtimer, ns_to_ktime(period),
10633 HRTIMER_MODE_REL_PINNED_HARD);
10636 static void perf_swevent_cancel_hrtimer(struct perf_event *event)
10638 struct hw_perf_event *hwc = &event->hw;
10640 if (is_sampling_event(event)) {
10641 ktime_t remaining = hrtimer_get_remaining(&hwc->hrtimer);
10642 local64_set(&hwc->period_left, ktime_to_ns(remaining));
10644 hrtimer_cancel(&hwc->hrtimer);
10648 static void perf_swevent_init_hrtimer(struct perf_event *event)
10650 struct hw_perf_event *hwc = &event->hw;
10652 if (!is_sampling_event(event))
10655 hrtimer_init(&hwc->hrtimer, CLOCK_MONOTONIC, HRTIMER_MODE_REL_HARD);
10656 hwc->hrtimer.function = perf_swevent_hrtimer;
10659 * Since hrtimers have a fixed rate, we can do a static freq->period
10660 * mapping and avoid the whole period adjust feedback stuff.
10662 if (event->attr.freq) {
10663 long freq = event->attr.sample_freq;
10665 event->attr.sample_period = NSEC_PER_SEC / freq;
10666 hwc->sample_period = event->attr.sample_period;
10667 local64_set(&hwc->period_left, hwc->sample_period);
10668 hwc->last_period = hwc->sample_period;
10669 event->attr.freq = 0;
10674 * Software event: cpu wall time clock
10677 static void cpu_clock_event_update(struct perf_event *event)
10682 now = local_clock();
10683 prev = local64_xchg(&event->hw.prev_count, now);
10684 local64_add(now - prev, &event->count);
10687 static void cpu_clock_event_start(struct perf_event *event, int flags)
10689 local64_set(&event->hw.prev_count, local_clock());
10690 perf_swevent_start_hrtimer(event);
10693 static void cpu_clock_event_stop(struct perf_event *event, int flags)
10695 perf_swevent_cancel_hrtimer(event);
10696 cpu_clock_event_update(event);
10699 static int cpu_clock_event_add(struct perf_event *event, int flags)
10701 if (flags & PERF_EF_START)
10702 cpu_clock_event_start(event, flags);
10703 perf_event_update_userpage(event);
10708 static void cpu_clock_event_del(struct perf_event *event, int flags)
10710 cpu_clock_event_stop(event, flags);
10713 static void cpu_clock_event_read(struct perf_event *event)
10715 cpu_clock_event_update(event);
10718 static int cpu_clock_event_init(struct perf_event *event)
10720 if (event->attr.type != PERF_TYPE_SOFTWARE)
10723 if (event->attr.config != PERF_COUNT_SW_CPU_CLOCK)
10727 * no branch sampling for software events
10729 if (has_branch_stack(event))
10730 return -EOPNOTSUPP;
10732 perf_swevent_init_hrtimer(event);
10737 static struct pmu perf_cpu_clock = {
10738 .task_ctx_nr = perf_sw_context,
10740 .capabilities = PERF_PMU_CAP_NO_NMI,
10742 .event_init = cpu_clock_event_init,
10743 .add = cpu_clock_event_add,
10744 .del = cpu_clock_event_del,
10745 .start = cpu_clock_event_start,
10746 .stop = cpu_clock_event_stop,
10747 .read = cpu_clock_event_read,
10751 * Software event: task time clock
10754 static void task_clock_event_update(struct perf_event *event, u64 now)
10759 prev = local64_xchg(&event->hw.prev_count, now);
10760 delta = now - prev;
10761 local64_add(delta, &event->count);
10764 static void task_clock_event_start(struct perf_event *event, int flags)
10766 local64_set(&event->hw.prev_count, event->ctx->time);
10767 perf_swevent_start_hrtimer(event);
10770 static void task_clock_event_stop(struct perf_event *event, int flags)
10772 perf_swevent_cancel_hrtimer(event);
10773 task_clock_event_update(event, event->ctx->time);
10776 static int task_clock_event_add(struct perf_event *event, int flags)
10778 if (flags & PERF_EF_START)
10779 task_clock_event_start(event, flags);
10780 perf_event_update_userpage(event);
10785 static void task_clock_event_del(struct perf_event *event, int flags)
10787 task_clock_event_stop(event, PERF_EF_UPDATE);
10790 static void task_clock_event_read(struct perf_event *event)
10792 u64 now = perf_clock();
10793 u64 delta = now - event->ctx->timestamp;
10794 u64 time = event->ctx->time + delta;
10796 task_clock_event_update(event, time);
10799 static int task_clock_event_init(struct perf_event *event)
10801 if (event->attr.type != PERF_TYPE_SOFTWARE)
10804 if (event->attr.config != PERF_COUNT_SW_TASK_CLOCK)
10808 * no branch sampling for software events
10810 if (has_branch_stack(event))
10811 return -EOPNOTSUPP;
10813 perf_swevent_init_hrtimer(event);
10818 static struct pmu perf_task_clock = {
10819 .task_ctx_nr = perf_sw_context,
10821 .capabilities = PERF_PMU_CAP_NO_NMI,
10823 .event_init = task_clock_event_init,
10824 .add = task_clock_event_add,
10825 .del = task_clock_event_del,
10826 .start = task_clock_event_start,
10827 .stop = task_clock_event_stop,
10828 .read = task_clock_event_read,
10831 static void perf_pmu_nop_void(struct pmu *pmu)
10835 static void perf_pmu_nop_txn(struct pmu *pmu, unsigned int flags)
10839 static int perf_pmu_nop_int(struct pmu *pmu)
10844 static int perf_event_nop_int(struct perf_event *event, u64 value)
10849 static DEFINE_PER_CPU(unsigned int, nop_txn_flags);
10851 static void perf_pmu_start_txn(struct pmu *pmu, unsigned int flags)
10853 __this_cpu_write(nop_txn_flags, flags);
10855 if (flags & ~PERF_PMU_TXN_ADD)
10858 perf_pmu_disable(pmu);
10861 static int perf_pmu_commit_txn(struct pmu *pmu)
10863 unsigned int flags = __this_cpu_read(nop_txn_flags);
10865 __this_cpu_write(nop_txn_flags, 0);
10867 if (flags & ~PERF_PMU_TXN_ADD)
10870 perf_pmu_enable(pmu);
10874 static void perf_pmu_cancel_txn(struct pmu *pmu)
10876 unsigned int flags = __this_cpu_read(nop_txn_flags);
10878 __this_cpu_write(nop_txn_flags, 0);
10880 if (flags & ~PERF_PMU_TXN_ADD)
10883 perf_pmu_enable(pmu);
10886 static int perf_event_idx_default(struct perf_event *event)
10892 * Ensures all contexts with the same task_ctx_nr have the same
10893 * pmu_cpu_context too.
10895 static struct perf_cpu_context __percpu *find_pmu_context(int ctxn)
10902 list_for_each_entry(pmu, &pmus, entry) {
10903 if (pmu->task_ctx_nr == ctxn)
10904 return pmu->pmu_cpu_context;
10910 static void free_pmu_context(struct pmu *pmu)
10913 * Static contexts such as perf_sw_context have a global lifetime
10914 * and may be shared between different PMUs. Avoid freeing them
10915 * when a single PMU is going away.
10917 if (pmu->task_ctx_nr > perf_invalid_context)
10920 free_percpu(pmu->pmu_cpu_context);
10924 * Let userspace know that this PMU supports address range filtering:
10926 static ssize_t nr_addr_filters_show(struct device *dev,
10927 struct device_attribute *attr,
10930 struct pmu *pmu = dev_get_drvdata(dev);
10932 return snprintf(page, PAGE_SIZE - 1, "%d\n", pmu->nr_addr_filters);
10934 DEVICE_ATTR_RO(nr_addr_filters);
10936 static struct idr pmu_idr;
10939 type_show(struct device *dev, struct device_attribute *attr, char *page)
10941 struct pmu *pmu = dev_get_drvdata(dev);
10943 return snprintf(page, PAGE_SIZE-1, "%d\n", pmu->type);
10945 static DEVICE_ATTR_RO(type);
10948 perf_event_mux_interval_ms_show(struct device *dev,
10949 struct device_attribute *attr,
10952 struct pmu *pmu = dev_get_drvdata(dev);
10954 return snprintf(page, PAGE_SIZE-1, "%d\n", pmu->hrtimer_interval_ms);
10957 static DEFINE_MUTEX(mux_interval_mutex);
10960 perf_event_mux_interval_ms_store(struct device *dev,
10961 struct device_attribute *attr,
10962 const char *buf, size_t count)
10964 struct pmu *pmu = dev_get_drvdata(dev);
10965 int timer, cpu, ret;
10967 ret = kstrtoint(buf, 0, &timer);
10974 /* same value, noting to do */
10975 if (timer == pmu->hrtimer_interval_ms)
10978 mutex_lock(&mux_interval_mutex);
10979 pmu->hrtimer_interval_ms = timer;
10981 /* update all cpuctx for this PMU */
10983 for_each_online_cpu(cpu) {
10984 struct perf_cpu_context *cpuctx;
10985 cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
10986 cpuctx->hrtimer_interval = ns_to_ktime(NSEC_PER_MSEC * timer);
10988 cpu_function_call(cpu,
10989 (remote_function_f)perf_mux_hrtimer_restart, cpuctx);
10991 cpus_read_unlock();
10992 mutex_unlock(&mux_interval_mutex);
10996 static DEVICE_ATTR_RW(perf_event_mux_interval_ms);
10998 static struct attribute *pmu_dev_attrs[] = {
10999 &dev_attr_type.attr,
11000 &dev_attr_perf_event_mux_interval_ms.attr,
11003 ATTRIBUTE_GROUPS(pmu_dev);
11005 static int pmu_bus_running;
11006 static struct bus_type pmu_bus = {
11007 .name = "event_source",
11008 .dev_groups = pmu_dev_groups,
11011 static void pmu_dev_release(struct device *dev)
11016 static int pmu_dev_alloc(struct pmu *pmu)
11020 pmu->dev = kzalloc(sizeof(struct device), GFP_KERNEL);
11024 pmu->dev->groups = pmu->attr_groups;
11025 device_initialize(pmu->dev);
11026 ret = dev_set_name(pmu->dev, "%s", pmu->name);
11030 dev_set_drvdata(pmu->dev, pmu);
11031 pmu->dev->bus = &pmu_bus;
11032 pmu->dev->release = pmu_dev_release;
11033 ret = device_add(pmu->dev);
11037 /* For PMUs with address filters, throw in an extra attribute: */
11038 if (pmu->nr_addr_filters)
11039 ret = device_create_file(pmu->dev, &dev_attr_nr_addr_filters);
11044 if (pmu->attr_update)
11045 ret = sysfs_update_groups(&pmu->dev->kobj, pmu->attr_update);
11054 device_del(pmu->dev);
11057 put_device(pmu->dev);
11061 static struct lock_class_key cpuctx_mutex;
11062 static struct lock_class_key cpuctx_lock;
11064 int perf_pmu_register(struct pmu *pmu, const char *name, int type)
11066 int cpu, ret, max = PERF_TYPE_MAX;
11068 mutex_lock(&pmus_lock);
11070 pmu->pmu_disable_count = alloc_percpu(int);
11071 if (!pmu->pmu_disable_count)
11079 if (type != PERF_TYPE_SOFTWARE) {
11083 ret = idr_alloc(&pmu_idr, pmu, max, 0, GFP_KERNEL);
11087 WARN_ON(type >= 0 && ret != type);
11093 if (pmu_bus_running) {
11094 ret = pmu_dev_alloc(pmu);
11100 if (pmu->task_ctx_nr == perf_hw_context) {
11101 static int hw_context_taken = 0;
11104 * Other than systems with heterogeneous CPUs, it never makes
11105 * sense for two PMUs to share perf_hw_context. PMUs which are
11106 * uncore must use perf_invalid_context.
11108 if (WARN_ON_ONCE(hw_context_taken &&
11109 !(pmu->capabilities & PERF_PMU_CAP_HETEROGENEOUS_CPUS)))
11110 pmu->task_ctx_nr = perf_invalid_context;
11112 hw_context_taken = 1;
11115 pmu->pmu_cpu_context = find_pmu_context(pmu->task_ctx_nr);
11116 if (pmu->pmu_cpu_context)
11117 goto got_cpu_context;
11120 pmu->pmu_cpu_context = alloc_percpu(struct perf_cpu_context);
11121 if (!pmu->pmu_cpu_context)
11124 for_each_possible_cpu(cpu) {
11125 struct perf_cpu_context *cpuctx;
11127 cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
11128 __perf_event_init_context(&cpuctx->ctx);
11129 lockdep_set_class(&cpuctx->ctx.mutex, &cpuctx_mutex);
11130 lockdep_set_class(&cpuctx->ctx.lock, &cpuctx_lock);
11131 cpuctx->ctx.pmu = pmu;
11132 cpuctx->online = cpumask_test_cpu(cpu, perf_online_mask);
11134 __perf_mux_hrtimer_init(cpuctx, cpu);
11136 cpuctx->heap_size = ARRAY_SIZE(cpuctx->heap_default);
11137 cpuctx->heap = cpuctx->heap_default;
11141 if (!pmu->start_txn) {
11142 if (pmu->pmu_enable) {
11144 * If we have pmu_enable/pmu_disable calls, install
11145 * transaction stubs that use that to try and batch
11146 * hardware accesses.
11148 pmu->start_txn = perf_pmu_start_txn;
11149 pmu->commit_txn = perf_pmu_commit_txn;
11150 pmu->cancel_txn = perf_pmu_cancel_txn;
11152 pmu->start_txn = perf_pmu_nop_txn;
11153 pmu->commit_txn = perf_pmu_nop_int;
11154 pmu->cancel_txn = perf_pmu_nop_void;
11158 if (!pmu->pmu_enable) {
11159 pmu->pmu_enable = perf_pmu_nop_void;
11160 pmu->pmu_disable = perf_pmu_nop_void;
11163 if (!pmu->check_period)
11164 pmu->check_period = perf_event_nop_int;
11166 if (!pmu->event_idx)
11167 pmu->event_idx = perf_event_idx_default;
11170 * Ensure the TYPE_SOFTWARE PMUs are at the head of the list,
11171 * since these cannot be in the IDR. This way the linear search
11172 * is fast, provided a valid software event is provided.
11174 if (type == PERF_TYPE_SOFTWARE || !name)
11175 list_add_rcu(&pmu->entry, &pmus);
11177 list_add_tail_rcu(&pmu->entry, &pmus);
11179 atomic_set(&pmu->exclusive_cnt, 0);
11182 mutex_unlock(&pmus_lock);
11187 device_del(pmu->dev);
11188 put_device(pmu->dev);
11191 if (pmu->type != PERF_TYPE_SOFTWARE)
11192 idr_remove(&pmu_idr, pmu->type);
11195 free_percpu(pmu->pmu_disable_count);
11198 EXPORT_SYMBOL_GPL(perf_pmu_register);
11200 void perf_pmu_unregister(struct pmu *pmu)
11202 mutex_lock(&pmus_lock);
11203 list_del_rcu(&pmu->entry);
11206 * We dereference the pmu list under both SRCU and regular RCU, so
11207 * synchronize against both of those.
11209 synchronize_srcu(&pmus_srcu);
11212 free_percpu(pmu->pmu_disable_count);
11213 if (pmu->type != PERF_TYPE_SOFTWARE)
11214 idr_remove(&pmu_idr, pmu->type);
11215 if (pmu_bus_running) {
11216 if (pmu->nr_addr_filters)
11217 device_remove_file(pmu->dev, &dev_attr_nr_addr_filters);
11218 device_del(pmu->dev);
11219 put_device(pmu->dev);
11221 free_pmu_context(pmu);
11222 mutex_unlock(&pmus_lock);
11224 EXPORT_SYMBOL_GPL(perf_pmu_unregister);
11226 static inline bool has_extended_regs(struct perf_event *event)
11228 return (event->attr.sample_regs_user & PERF_REG_EXTENDED_MASK) ||
11229 (event->attr.sample_regs_intr & PERF_REG_EXTENDED_MASK);
11232 static int perf_try_init_event(struct pmu *pmu, struct perf_event *event)
11234 struct perf_event_context *ctx = NULL;
11237 if (!try_module_get(pmu->module))
11241 * A number of pmu->event_init() methods iterate the sibling_list to,
11242 * for example, validate if the group fits on the PMU. Therefore,
11243 * if this is a sibling event, acquire the ctx->mutex to protect
11244 * the sibling_list.
11246 if (event->group_leader != event && pmu->task_ctx_nr != perf_sw_context) {
11248 * This ctx->mutex can nest when we're called through
11249 * inheritance. See the perf_event_ctx_lock_nested() comment.
11251 ctx = perf_event_ctx_lock_nested(event->group_leader,
11252 SINGLE_DEPTH_NESTING);
11257 ret = pmu->event_init(event);
11260 perf_event_ctx_unlock(event->group_leader, ctx);
11263 if (!(pmu->capabilities & PERF_PMU_CAP_EXTENDED_REGS) &&
11264 has_extended_regs(event))
11267 if (pmu->capabilities & PERF_PMU_CAP_NO_EXCLUDE &&
11268 event_has_any_exclude_flag(event))
11271 if (ret && event->destroy)
11272 event->destroy(event);
11276 module_put(pmu->module);
11281 static struct pmu *perf_init_event(struct perf_event *event)
11283 bool extended_type = false;
11284 int idx, type, ret;
11287 idx = srcu_read_lock(&pmus_srcu);
11289 /* Try parent's PMU first: */
11290 if (event->parent && event->parent->pmu) {
11291 pmu = event->parent->pmu;
11292 ret = perf_try_init_event(pmu, event);
11298 * PERF_TYPE_HARDWARE and PERF_TYPE_HW_CACHE
11299 * are often aliases for PERF_TYPE_RAW.
11301 type = event->attr.type;
11302 if (type == PERF_TYPE_HARDWARE || type == PERF_TYPE_HW_CACHE) {
11303 type = event->attr.config >> PERF_PMU_TYPE_SHIFT;
11305 type = PERF_TYPE_RAW;
11307 extended_type = true;
11308 event->attr.config &= PERF_HW_EVENT_MASK;
11314 pmu = idr_find(&pmu_idr, type);
11317 if (event->attr.type != type && type != PERF_TYPE_RAW &&
11318 !(pmu->capabilities & PERF_PMU_CAP_EXTENDED_HW_TYPE))
11321 ret = perf_try_init_event(pmu, event);
11322 if (ret == -ENOENT && event->attr.type != type && !extended_type) {
11323 type = event->attr.type;
11328 pmu = ERR_PTR(ret);
11333 list_for_each_entry_rcu(pmu, &pmus, entry, lockdep_is_held(&pmus_srcu)) {
11334 ret = perf_try_init_event(pmu, event);
11338 if (ret != -ENOENT) {
11339 pmu = ERR_PTR(ret);
11344 pmu = ERR_PTR(-ENOENT);
11346 srcu_read_unlock(&pmus_srcu, idx);
11351 static void attach_sb_event(struct perf_event *event)
11353 struct pmu_event_list *pel = per_cpu_ptr(&pmu_sb_events, event->cpu);
11355 raw_spin_lock(&pel->lock);
11356 list_add_rcu(&event->sb_list, &pel->list);
11357 raw_spin_unlock(&pel->lock);
11361 * We keep a list of all !task (and therefore per-cpu) events
11362 * that need to receive side-band records.
11364 * This avoids having to scan all the various PMU per-cpu contexts
11365 * looking for them.
11367 static void account_pmu_sb_event(struct perf_event *event)
11369 if (is_sb_event(event))
11370 attach_sb_event(event);
11373 static void account_event_cpu(struct perf_event *event, int cpu)
11378 if (is_cgroup_event(event))
11379 atomic_inc(&per_cpu(perf_cgroup_events, cpu));
11382 /* Freq events need the tick to stay alive (see perf_event_task_tick). */
11383 static void account_freq_event_nohz(void)
11385 #ifdef CONFIG_NO_HZ_FULL
11386 /* Lock so we don't race with concurrent unaccount */
11387 spin_lock(&nr_freq_lock);
11388 if (atomic_inc_return(&nr_freq_events) == 1)
11389 tick_nohz_dep_set(TICK_DEP_BIT_PERF_EVENTS);
11390 spin_unlock(&nr_freq_lock);
11394 static void account_freq_event(void)
11396 if (tick_nohz_full_enabled())
11397 account_freq_event_nohz();
11399 atomic_inc(&nr_freq_events);
11403 static void account_event(struct perf_event *event)
11410 if (event->attach_state & (PERF_ATTACH_TASK | PERF_ATTACH_SCHED_CB))
11412 if (event->attr.mmap || event->attr.mmap_data)
11413 atomic_inc(&nr_mmap_events);
11414 if (event->attr.build_id)
11415 atomic_inc(&nr_build_id_events);
11416 if (event->attr.comm)
11417 atomic_inc(&nr_comm_events);
11418 if (event->attr.namespaces)
11419 atomic_inc(&nr_namespaces_events);
11420 if (event->attr.cgroup)
11421 atomic_inc(&nr_cgroup_events);
11422 if (event->attr.task)
11423 atomic_inc(&nr_task_events);
11424 if (event->attr.freq)
11425 account_freq_event();
11426 if (event->attr.context_switch) {
11427 atomic_inc(&nr_switch_events);
11430 if (has_branch_stack(event))
11432 if (is_cgroup_event(event))
11434 if (event->attr.ksymbol)
11435 atomic_inc(&nr_ksymbol_events);
11436 if (event->attr.bpf_event)
11437 atomic_inc(&nr_bpf_events);
11438 if (event->attr.text_poke)
11439 atomic_inc(&nr_text_poke_events);
11443 * We need the mutex here because static_branch_enable()
11444 * must complete *before* the perf_sched_count increment
11447 if (atomic_inc_not_zero(&perf_sched_count))
11450 mutex_lock(&perf_sched_mutex);
11451 if (!atomic_read(&perf_sched_count)) {
11452 static_branch_enable(&perf_sched_events);
11454 * Guarantee that all CPUs observe they key change and
11455 * call the perf scheduling hooks before proceeding to
11456 * install events that need them.
11461 * Now that we have waited for the sync_sched(), allow further
11462 * increments to by-pass the mutex.
11464 atomic_inc(&perf_sched_count);
11465 mutex_unlock(&perf_sched_mutex);
11469 account_event_cpu(event, event->cpu);
11471 account_pmu_sb_event(event);
11475 * Allocate and initialize an event structure
11477 static struct perf_event *
11478 perf_event_alloc(struct perf_event_attr *attr, int cpu,
11479 struct task_struct *task,
11480 struct perf_event *group_leader,
11481 struct perf_event *parent_event,
11482 perf_overflow_handler_t overflow_handler,
11483 void *context, int cgroup_fd)
11486 struct perf_event *event;
11487 struct hw_perf_event *hwc;
11488 long err = -EINVAL;
11491 if ((unsigned)cpu >= nr_cpu_ids) {
11492 if (!task || cpu != -1)
11493 return ERR_PTR(-EINVAL);
11495 if (attr->sigtrap && !task) {
11496 /* Requires a task: avoid signalling random tasks. */
11497 return ERR_PTR(-EINVAL);
11500 node = (cpu >= 0) ? cpu_to_node(cpu) : -1;
11501 event = kmem_cache_alloc_node(perf_event_cache, GFP_KERNEL | __GFP_ZERO,
11504 return ERR_PTR(-ENOMEM);
11507 * Single events are their own group leaders, with an
11508 * empty sibling list:
11511 group_leader = event;
11513 mutex_init(&event->child_mutex);
11514 INIT_LIST_HEAD(&event->child_list);
11516 INIT_LIST_HEAD(&event->event_entry);
11517 INIT_LIST_HEAD(&event->sibling_list);
11518 INIT_LIST_HEAD(&event->active_list);
11519 init_event_group(event);
11520 INIT_LIST_HEAD(&event->rb_entry);
11521 INIT_LIST_HEAD(&event->active_entry);
11522 INIT_LIST_HEAD(&event->addr_filters.list);
11523 INIT_HLIST_NODE(&event->hlist_entry);
11526 init_waitqueue_head(&event->waitq);
11527 event->pending_disable = -1;
11528 init_irq_work(&event->pending, perf_pending_event);
11530 mutex_init(&event->mmap_mutex);
11531 raw_spin_lock_init(&event->addr_filters.lock);
11533 atomic_long_set(&event->refcount, 1);
11535 event->attr = *attr;
11536 event->group_leader = group_leader;
11540 event->parent = parent_event;
11542 event->ns = get_pid_ns(task_active_pid_ns(current));
11543 event->id = atomic64_inc_return(&perf_event_id);
11545 event->state = PERF_EVENT_STATE_INACTIVE;
11548 event->event_caps = parent_event->event_caps;
11550 if (event->attr.sigtrap)
11551 atomic_set(&event->event_limit, 1);
11554 event->attach_state = PERF_ATTACH_TASK;
11556 * XXX pmu::event_init needs to know what task to account to
11557 * and we cannot use the ctx information because we need the
11558 * pmu before we get a ctx.
11560 event->hw.target = get_task_struct(task);
11563 event->clock = &local_clock;
11565 event->clock = parent_event->clock;
11567 if (!overflow_handler && parent_event) {
11568 overflow_handler = parent_event->overflow_handler;
11569 context = parent_event->overflow_handler_context;
11570 #if defined(CONFIG_BPF_SYSCALL) && defined(CONFIG_EVENT_TRACING)
11571 if (overflow_handler == bpf_overflow_handler) {
11572 struct bpf_prog *prog = parent_event->prog;
11574 bpf_prog_inc(prog);
11575 event->prog = prog;
11576 event->orig_overflow_handler =
11577 parent_event->orig_overflow_handler;
11582 if (overflow_handler) {
11583 event->overflow_handler = overflow_handler;
11584 event->overflow_handler_context = context;
11585 } else if (is_write_backward(event)){
11586 event->overflow_handler = perf_event_output_backward;
11587 event->overflow_handler_context = NULL;
11589 event->overflow_handler = perf_event_output_forward;
11590 event->overflow_handler_context = NULL;
11593 perf_event__state_init(event);
11598 hwc->sample_period = attr->sample_period;
11599 if (attr->freq && attr->sample_freq)
11600 hwc->sample_period = 1;
11601 hwc->last_period = hwc->sample_period;
11603 local64_set(&hwc->period_left, hwc->sample_period);
11606 * We currently do not support PERF_SAMPLE_READ on inherited events.
11607 * See perf_output_read().
11609 if (attr->inherit && (attr->sample_type & PERF_SAMPLE_READ))
11612 if (!has_branch_stack(event))
11613 event->attr.branch_sample_type = 0;
11615 pmu = perf_init_event(event);
11617 err = PTR_ERR(pmu);
11622 * Disallow uncore-cgroup events, they don't make sense as the cgroup will
11623 * be different on other CPUs in the uncore mask.
11625 if (pmu->task_ctx_nr == perf_invalid_context && cgroup_fd != -1) {
11630 if (event->attr.aux_output &&
11631 !(pmu->capabilities & PERF_PMU_CAP_AUX_OUTPUT)) {
11636 if (cgroup_fd != -1) {
11637 err = perf_cgroup_connect(cgroup_fd, event, attr, group_leader);
11642 err = exclusive_event_init(event);
11646 if (has_addr_filter(event)) {
11647 event->addr_filter_ranges = kcalloc(pmu->nr_addr_filters,
11648 sizeof(struct perf_addr_filter_range),
11650 if (!event->addr_filter_ranges) {
11656 * Clone the parent's vma offsets: they are valid until exec()
11657 * even if the mm is not shared with the parent.
11659 if (event->parent) {
11660 struct perf_addr_filters_head *ifh = perf_event_addr_filters(event);
11662 raw_spin_lock_irq(&ifh->lock);
11663 memcpy(event->addr_filter_ranges,
11664 event->parent->addr_filter_ranges,
11665 pmu->nr_addr_filters * sizeof(struct perf_addr_filter_range));
11666 raw_spin_unlock_irq(&ifh->lock);
11669 /* force hw sync on the address filters */
11670 event->addr_filters_gen = 1;
11673 if (!event->parent) {
11674 if (event->attr.sample_type & PERF_SAMPLE_CALLCHAIN) {
11675 err = get_callchain_buffers(attr->sample_max_stack);
11677 goto err_addr_filters;
11681 err = security_perf_event_alloc(event);
11683 goto err_callchain_buffer;
11685 /* symmetric to unaccount_event() in _free_event() */
11686 account_event(event);
11690 err_callchain_buffer:
11691 if (!event->parent) {
11692 if (event->attr.sample_type & PERF_SAMPLE_CALLCHAIN)
11693 put_callchain_buffers();
11696 kfree(event->addr_filter_ranges);
11699 exclusive_event_destroy(event);
11702 if (is_cgroup_event(event))
11703 perf_detach_cgroup(event);
11704 if (event->destroy)
11705 event->destroy(event);
11706 module_put(pmu->module);
11709 put_pid_ns(event->ns);
11710 if (event->hw.target)
11711 put_task_struct(event->hw.target);
11712 kmem_cache_free(perf_event_cache, event);
11714 return ERR_PTR(err);
11717 static int perf_copy_attr(struct perf_event_attr __user *uattr,
11718 struct perf_event_attr *attr)
11723 /* Zero the full structure, so that a short copy will be nice. */
11724 memset(attr, 0, sizeof(*attr));
11726 ret = get_user(size, &uattr->size);
11730 /* ABI compatibility quirk: */
11732 size = PERF_ATTR_SIZE_VER0;
11733 if (size < PERF_ATTR_SIZE_VER0 || size > PAGE_SIZE)
11736 ret = copy_struct_from_user(attr, sizeof(*attr), uattr, size);
11745 if (attr->__reserved_1 || attr->__reserved_2 || attr->__reserved_3)
11748 if (attr->sample_type & ~(PERF_SAMPLE_MAX-1))
11751 if (attr->read_format & ~(PERF_FORMAT_MAX-1))
11754 if (attr->sample_type & PERF_SAMPLE_BRANCH_STACK) {
11755 u64 mask = attr->branch_sample_type;
11757 /* only using defined bits */
11758 if (mask & ~(PERF_SAMPLE_BRANCH_MAX-1))
11761 /* at least one branch bit must be set */
11762 if (!(mask & ~PERF_SAMPLE_BRANCH_PLM_ALL))
11765 /* propagate priv level, when not set for branch */
11766 if (!(mask & PERF_SAMPLE_BRANCH_PLM_ALL)) {
11768 /* exclude_kernel checked on syscall entry */
11769 if (!attr->exclude_kernel)
11770 mask |= PERF_SAMPLE_BRANCH_KERNEL;
11772 if (!attr->exclude_user)
11773 mask |= PERF_SAMPLE_BRANCH_USER;
11775 if (!attr->exclude_hv)
11776 mask |= PERF_SAMPLE_BRANCH_HV;
11778 * adjust user setting (for HW filter setup)
11780 attr->branch_sample_type = mask;
11782 /* privileged levels capture (kernel, hv): check permissions */
11783 if (mask & PERF_SAMPLE_BRANCH_PERM_PLM) {
11784 ret = perf_allow_kernel(attr);
11790 if (attr->sample_type & PERF_SAMPLE_REGS_USER) {
11791 ret = perf_reg_validate(attr->sample_regs_user);
11796 if (attr->sample_type & PERF_SAMPLE_STACK_USER) {
11797 if (!arch_perf_have_user_stack_dump())
11801 * We have __u32 type for the size, but so far
11802 * we can only use __u16 as maximum due to the
11803 * __u16 sample size limit.
11805 if (attr->sample_stack_user >= USHRT_MAX)
11807 else if (!IS_ALIGNED(attr->sample_stack_user, sizeof(u64)))
11811 if (!attr->sample_max_stack)
11812 attr->sample_max_stack = sysctl_perf_event_max_stack;
11814 if (attr->sample_type & PERF_SAMPLE_REGS_INTR)
11815 ret = perf_reg_validate(attr->sample_regs_intr);
11817 #ifndef CONFIG_CGROUP_PERF
11818 if (attr->sample_type & PERF_SAMPLE_CGROUP)
11821 if ((attr->sample_type & PERF_SAMPLE_WEIGHT) &&
11822 (attr->sample_type & PERF_SAMPLE_WEIGHT_STRUCT))
11825 if (!attr->inherit && attr->inherit_thread)
11828 if (attr->remove_on_exec && attr->enable_on_exec)
11831 if (attr->sigtrap && !attr->remove_on_exec)
11838 put_user(sizeof(*attr), &uattr->size);
11843 static void mutex_lock_double(struct mutex *a, struct mutex *b)
11849 mutex_lock_nested(b, SINGLE_DEPTH_NESTING);
11853 perf_event_set_output(struct perf_event *event, struct perf_event *output_event)
11855 struct perf_buffer *rb = NULL;
11858 if (!output_event) {
11859 mutex_lock(&event->mmap_mutex);
11863 /* don't allow circular references */
11864 if (event == output_event)
11868 * Don't allow cross-cpu buffers
11870 if (output_event->cpu != event->cpu)
11874 * If its not a per-cpu rb, it must be the same task.
11876 if (output_event->cpu == -1 && output_event->ctx != event->ctx)
11880 * Mixing clocks in the same buffer is trouble you don't need.
11882 if (output_event->clock != event->clock)
11886 * Either writing ring buffer from beginning or from end.
11887 * Mixing is not allowed.
11889 if (is_write_backward(output_event) != is_write_backward(event))
11893 * If both events generate aux data, they must be on the same PMU
11895 if (has_aux(event) && has_aux(output_event) &&
11896 event->pmu != output_event->pmu)
11900 * Hold both mmap_mutex to serialize against perf_mmap_close(). Since
11901 * output_event is already on rb->event_list, and the list iteration
11902 * restarts after every removal, it is guaranteed this new event is
11903 * observed *OR* if output_event is already removed, it's guaranteed we
11904 * observe !rb->mmap_count.
11906 mutex_lock_double(&event->mmap_mutex, &output_event->mmap_mutex);
11908 /* Can't redirect output if we've got an active mmap() */
11909 if (atomic_read(&event->mmap_count))
11912 if (output_event) {
11913 /* get the rb we want to redirect to */
11914 rb = ring_buffer_get(output_event);
11918 /* did we race against perf_mmap_close() */
11919 if (!atomic_read(&rb->mmap_count)) {
11920 ring_buffer_put(rb);
11925 ring_buffer_attach(event, rb);
11929 mutex_unlock(&event->mmap_mutex);
11931 mutex_unlock(&output_event->mmap_mutex);
11937 static int perf_event_set_clock(struct perf_event *event, clockid_t clk_id)
11939 bool nmi_safe = false;
11942 case CLOCK_MONOTONIC:
11943 event->clock = &ktime_get_mono_fast_ns;
11947 case CLOCK_MONOTONIC_RAW:
11948 event->clock = &ktime_get_raw_fast_ns;
11952 case CLOCK_REALTIME:
11953 event->clock = &ktime_get_real_ns;
11956 case CLOCK_BOOTTIME:
11957 event->clock = &ktime_get_boottime_ns;
11961 event->clock = &ktime_get_clocktai_ns;
11968 if (!nmi_safe && !(event->pmu->capabilities & PERF_PMU_CAP_NO_NMI))
11975 * Variation on perf_event_ctx_lock_nested(), except we take two context
11978 static struct perf_event_context *
11979 __perf_event_ctx_lock_double(struct perf_event *group_leader,
11980 struct perf_event_context *ctx)
11982 struct perf_event_context *gctx;
11986 gctx = READ_ONCE(group_leader->ctx);
11987 if (!refcount_inc_not_zero(&gctx->refcount)) {
11993 mutex_lock_double(&gctx->mutex, &ctx->mutex);
11995 if (group_leader->ctx != gctx) {
11996 mutex_unlock(&ctx->mutex);
11997 mutex_unlock(&gctx->mutex);
12006 perf_check_permission(struct perf_event_attr *attr, struct task_struct *task)
12008 unsigned int ptrace_mode = PTRACE_MODE_READ_REALCREDS;
12009 bool is_capable = perfmon_capable();
12011 if (attr->sigtrap) {
12013 * perf_event_attr::sigtrap sends signals to the other task.
12014 * Require the current task to also have CAP_KILL.
12017 is_capable &= ns_capable(__task_cred(task)->user_ns, CAP_KILL);
12021 * If the required capabilities aren't available, checks for
12022 * ptrace permissions: upgrade to ATTACH, since sending signals
12023 * can effectively change the target task.
12025 ptrace_mode = PTRACE_MODE_ATTACH_REALCREDS;
12029 * Preserve ptrace permission check for backwards compatibility. The
12030 * ptrace check also includes checks that the current task and other
12031 * task have matching uids, and is therefore not done here explicitly.
12033 return is_capable || ptrace_may_access(task, ptrace_mode);
12037 * sys_perf_event_open - open a performance event, associate it to a task/cpu
12039 * @attr_uptr: event_id type attributes for monitoring/sampling
12042 * @group_fd: group leader event fd
12043 * @flags: perf event open flags
12045 SYSCALL_DEFINE5(perf_event_open,
12046 struct perf_event_attr __user *, attr_uptr,
12047 pid_t, pid, int, cpu, int, group_fd, unsigned long, flags)
12049 struct perf_event *group_leader = NULL, *output_event = NULL;
12050 struct perf_event *event, *sibling;
12051 struct perf_event_attr attr;
12052 struct perf_event_context *ctx, *gctx;
12053 struct file *event_file = NULL;
12054 struct fd group = {NULL, 0};
12055 struct task_struct *task = NULL;
12058 int move_group = 0;
12060 int f_flags = O_RDWR;
12061 int cgroup_fd = -1;
12063 /* for future expandability... */
12064 if (flags & ~PERF_FLAG_ALL)
12067 /* Do we allow access to perf_event_open(2) ? */
12068 err = security_perf_event_open(&attr, PERF_SECURITY_OPEN);
12072 err = perf_copy_attr(attr_uptr, &attr);
12076 if (!attr.exclude_kernel) {
12077 err = perf_allow_kernel(&attr);
12082 if (attr.namespaces) {
12083 if (!perfmon_capable())
12088 if (attr.sample_freq > sysctl_perf_event_sample_rate)
12091 if (attr.sample_period & (1ULL << 63))
12095 /* Only privileged users can get physical addresses */
12096 if ((attr.sample_type & PERF_SAMPLE_PHYS_ADDR)) {
12097 err = perf_allow_kernel(&attr);
12102 /* REGS_INTR can leak data, lockdown must prevent this */
12103 if (attr.sample_type & PERF_SAMPLE_REGS_INTR) {
12104 err = security_locked_down(LOCKDOWN_PERF);
12110 * In cgroup mode, the pid argument is used to pass the fd
12111 * opened to the cgroup directory in cgroupfs. The cpu argument
12112 * designates the cpu on which to monitor threads from that
12115 if ((flags & PERF_FLAG_PID_CGROUP) && (pid == -1 || cpu == -1))
12118 if (flags & PERF_FLAG_FD_CLOEXEC)
12119 f_flags |= O_CLOEXEC;
12121 event_fd = get_unused_fd_flags(f_flags);
12125 if (group_fd != -1) {
12126 err = perf_fget_light(group_fd, &group);
12129 group_leader = group.file->private_data;
12130 if (flags & PERF_FLAG_FD_OUTPUT)
12131 output_event = group_leader;
12132 if (flags & PERF_FLAG_FD_NO_GROUP)
12133 group_leader = NULL;
12136 if (pid != -1 && !(flags & PERF_FLAG_PID_CGROUP)) {
12137 task = find_lively_task_by_vpid(pid);
12138 if (IS_ERR(task)) {
12139 err = PTR_ERR(task);
12144 if (task && group_leader &&
12145 group_leader->attr.inherit != attr.inherit) {
12150 if (flags & PERF_FLAG_PID_CGROUP)
12153 event = perf_event_alloc(&attr, cpu, task, group_leader, NULL,
12154 NULL, NULL, cgroup_fd);
12155 if (IS_ERR(event)) {
12156 err = PTR_ERR(event);
12160 if (is_sampling_event(event)) {
12161 if (event->pmu->capabilities & PERF_PMU_CAP_NO_INTERRUPT) {
12168 * Special case software events and allow them to be part of
12169 * any hardware group.
12173 if (attr.use_clockid) {
12174 err = perf_event_set_clock(event, attr.clockid);
12179 if (pmu->task_ctx_nr == perf_sw_context)
12180 event->event_caps |= PERF_EV_CAP_SOFTWARE;
12182 if (group_leader) {
12183 if (is_software_event(event) &&
12184 !in_software_context(group_leader)) {
12186 * If the event is a sw event, but the group_leader
12187 * is on hw context.
12189 * Allow the addition of software events to hw
12190 * groups, this is safe because software events
12191 * never fail to schedule.
12193 pmu = group_leader->ctx->pmu;
12194 } else if (!is_software_event(event) &&
12195 is_software_event(group_leader) &&
12196 (group_leader->group_caps & PERF_EV_CAP_SOFTWARE)) {
12198 * In case the group is a pure software group, and we
12199 * try to add a hardware event, move the whole group to
12200 * the hardware context.
12207 * Get the target context (task or percpu):
12209 ctx = find_get_context(pmu, task, event);
12211 err = PTR_ERR(ctx);
12216 * Look up the group leader (we will attach this event to it):
12218 if (group_leader) {
12222 * Do not allow a recursive hierarchy (this new sibling
12223 * becoming part of another group-sibling):
12225 if (group_leader->group_leader != group_leader)
12228 /* All events in a group should have the same clock */
12229 if (group_leader->clock != event->clock)
12233 * Make sure we're both events for the same CPU;
12234 * grouping events for different CPUs is broken; since
12235 * you can never concurrently schedule them anyhow.
12237 if (group_leader->cpu != event->cpu)
12241 * Make sure we're both on the same task, or both
12244 if (group_leader->ctx->task != ctx->task)
12248 * Do not allow to attach to a group in a different task
12249 * or CPU context. If we're moving SW events, we'll fix
12250 * this up later, so allow that.
12252 * Racy, not holding group_leader->ctx->mutex, see comment with
12253 * perf_event_ctx_lock().
12255 if (!move_group && group_leader->ctx != ctx)
12259 * Only a group leader can be exclusive or pinned
12261 if (attr.exclusive || attr.pinned)
12265 if (output_event) {
12266 err = perf_event_set_output(event, output_event);
12271 event_file = anon_inode_getfile("[perf_event]", &perf_fops, event,
12273 if (IS_ERR(event_file)) {
12274 err = PTR_ERR(event_file);
12280 err = down_read_interruptible(&task->signal->exec_update_lock);
12285 * We must hold exec_update_lock across this and any potential
12286 * perf_install_in_context() call for this new event to
12287 * serialize against exec() altering our credentials (and the
12288 * perf_event_exit_task() that could imply).
12291 if (!perf_check_permission(&attr, task))
12296 gctx = __perf_event_ctx_lock_double(group_leader, ctx);
12298 if (gctx->task == TASK_TOMBSTONE) {
12304 * Check if we raced against another sys_perf_event_open() call
12305 * moving the software group underneath us.
12307 if (!(group_leader->group_caps & PERF_EV_CAP_SOFTWARE)) {
12309 * If someone moved the group out from under us, check
12310 * if this new event wound up on the same ctx, if so
12311 * its the regular !move_group case, otherwise fail.
12317 perf_event_ctx_unlock(group_leader, gctx);
12319 goto not_move_group;
12324 * Failure to create exclusive events returns -EBUSY.
12327 if (!exclusive_event_installable(group_leader, ctx))
12330 for_each_sibling_event(sibling, group_leader) {
12331 if (!exclusive_event_installable(sibling, ctx))
12335 mutex_lock(&ctx->mutex);
12338 * Now that we hold ctx->lock, (re)validate group_leader->ctx == ctx,
12339 * see the group_leader && !move_group test earlier.
12341 if (group_leader && group_leader->ctx != ctx) {
12348 if (ctx->task == TASK_TOMBSTONE) {
12353 if (!perf_event_validate_size(event)) {
12360 * Check if the @cpu we're creating an event for is online.
12362 * We use the perf_cpu_context::ctx::mutex to serialize against
12363 * the hotplug notifiers. See perf_event_{init,exit}_cpu().
12365 struct perf_cpu_context *cpuctx =
12366 container_of(ctx, struct perf_cpu_context, ctx);
12368 if (!cpuctx->online) {
12374 if (perf_need_aux_event(event) && !perf_get_aux_event(event, group_leader)) {
12380 * Must be under the same ctx::mutex as perf_install_in_context(),
12381 * because we need to serialize with concurrent event creation.
12383 if (!exclusive_event_installable(event, ctx)) {
12388 WARN_ON_ONCE(ctx->parent_ctx);
12391 * This is the point on no return; we cannot fail hereafter. This is
12392 * where we start modifying current state.
12397 * See perf_event_ctx_lock() for comments on the details
12398 * of swizzling perf_event::ctx.
12400 perf_remove_from_context(group_leader, 0);
12403 for_each_sibling_event(sibling, group_leader) {
12404 perf_remove_from_context(sibling, 0);
12409 * Wait for everybody to stop referencing the events through
12410 * the old lists, before installing it on new lists.
12415 * Install the group siblings before the group leader.
12417 * Because a group leader will try and install the entire group
12418 * (through the sibling list, which is still in-tact), we can
12419 * end up with siblings installed in the wrong context.
12421 * By installing siblings first we NO-OP because they're not
12422 * reachable through the group lists.
12424 for_each_sibling_event(sibling, group_leader) {
12425 perf_event__state_init(sibling);
12426 perf_install_in_context(ctx, sibling, sibling->cpu);
12431 * Removing from the context ends up with disabled
12432 * event. What we want here is event in the initial
12433 * startup state, ready to be add into new context.
12435 perf_event__state_init(group_leader);
12436 perf_install_in_context(ctx, group_leader, group_leader->cpu);
12441 * Precalculate sample_data sizes; do while holding ctx::mutex such
12442 * that we're serialized against further additions and before
12443 * perf_install_in_context() which is the point the event is active and
12444 * can use these values.
12446 perf_event__header_size(event);
12447 perf_event__id_header_size(event);
12449 event->owner = current;
12451 perf_install_in_context(ctx, event, event->cpu);
12452 perf_unpin_context(ctx);
12455 perf_event_ctx_unlock(group_leader, gctx);
12456 mutex_unlock(&ctx->mutex);
12459 up_read(&task->signal->exec_update_lock);
12460 put_task_struct(task);
12463 mutex_lock(¤t->perf_event_mutex);
12464 list_add_tail(&event->owner_entry, ¤t->perf_event_list);
12465 mutex_unlock(¤t->perf_event_mutex);
12468 * Drop the reference on the group_event after placing the
12469 * new event on the sibling_list. This ensures destruction
12470 * of the group leader will find the pointer to itself in
12471 * perf_group_detach().
12474 fd_install(event_fd, event_file);
12479 perf_event_ctx_unlock(group_leader, gctx);
12480 mutex_unlock(&ctx->mutex);
12483 up_read(&task->signal->exec_update_lock);
12487 perf_unpin_context(ctx);
12491 * If event_file is set, the fput() above will have called ->release()
12492 * and that will take care of freeing the event.
12498 put_task_struct(task);
12502 put_unused_fd(event_fd);
12507 * perf_event_create_kernel_counter
12509 * @attr: attributes of the counter to create
12510 * @cpu: cpu in which the counter is bound
12511 * @task: task to profile (NULL for percpu)
12512 * @overflow_handler: callback to trigger when we hit the event
12513 * @context: context data could be used in overflow_handler callback
12515 struct perf_event *
12516 perf_event_create_kernel_counter(struct perf_event_attr *attr, int cpu,
12517 struct task_struct *task,
12518 perf_overflow_handler_t overflow_handler,
12521 struct perf_event_context *ctx;
12522 struct perf_event *event;
12526 * Grouping is not supported for kernel events, neither is 'AUX',
12527 * make sure the caller's intentions are adjusted.
12529 if (attr->aux_output)
12530 return ERR_PTR(-EINVAL);
12532 event = perf_event_alloc(attr, cpu, task, NULL, NULL,
12533 overflow_handler, context, -1);
12534 if (IS_ERR(event)) {
12535 err = PTR_ERR(event);
12539 /* Mark owner so we could distinguish it from user events. */
12540 event->owner = TASK_TOMBSTONE;
12543 * Get the target context (task or percpu):
12545 ctx = find_get_context(event->pmu, task, event);
12547 err = PTR_ERR(ctx);
12551 WARN_ON_ONCE(ctx->parent_ctx);
12552 mutex_lock(&ctx->mutex);
12553 if (ctx->task == TASK_TOMBSTONE) {
12560 * Check if the @cpu we're creating an event for is online.
12562 * We use the perf_cpu_context::ctx::mutex to serialize against
12563 * the hotplug notifiers. See perf_event_{init,exit}_cpu().
12565 struct perf_cpu_context *cpuctx =
12566 container_of(ctx, struct perf_cpu_context, ctx);
12567 if (!cpuctx->online) {
12573 if (!exclusive_event_installable(event, ctx)) {
12578 perf_install_in_context(ctx, event, event->cpu);
12579 perf_unpin_context(ctx);
12580 mutex_unlock(&ctx->mutex);
12585 mutex_unlock(&ctx->mutex);
12586 perf_unpin_context(ctx);
12591 return ERR_PTR(err);
12593 EXPORT_SYMBOL_GPL(perf_event_create_kernel_counter);
12595 void perf_pmu_migrate_context(struct pmu *pmu, int src_cpu, int dst_cpu)
12597 struct perf_event_context *src_ctx;
12598 struct perf_event_context *dst_ctx;
12599 struct perf_event *event, *tmp;
12602 src_ctx = &per_cpu_ptr(pmu->pmu_cpu_context, src_cpu)->ctx;
12603 dst_ctx = &per_cpu_ptr(pmu->pmu_cpu_context, dst_cpu)->ctx;
12606 * See perf_event_ctx_lock() for comments on the details
12607 * of swizzling perf_event::ctx.
12609 mutex_lock_double(&src_ctx->mutex, &dst_ctx->mutex);
12610 list_for_each_entry_safe(event, tmp, &src_ctx->event_list,
12612 perf_remove_from_context(event, 0);
12613 unaccount_event_cpu(event, src_cpu);
12615 list_add(&event->migrate_entry, &events);
12619 * Wait for the events to quiesce before re-instating them.
12624 * Re-instate events in 2 passes.
12626 * Skip over group leaders and only install siblings on this first
12627 * pass, siblings will not get enabled without a leader, however a
12628 * leader will enable its siblings, even if those are still on the old
12631 list_for_each_entry_safe(event, tmp, &events, migrate_entry) {
12632 if (event->group_leader == event)
12635 list_del(&event->migrate_entry);
12636 if (event->state >= PERF_EVENT_STATE_OFF)
12637 event->state = PERF_EVENT_STATE_INACTIVE;
12638 account_event_cpu(event, dst_cpu);
12639 perf_install_in_context(dst_ctx, event, dst_cpu);
12644 * Once all the siblings are setup properly, install the group leaders
12647 list_for_each_entry_safe(event, tmp, &events, migrate_entry) {
12648 list_del(&event->migrate_entry);
12649 if (event->state >= PERF_EVENT_STATE_OFF)
12650 event->state = PERF_EVENT_STATE_INACTIVE;
12651 account_event_cpu(event, dst_cpu);
12652 perf_install_in_context(dst_ctx, event, dst_cpu);
12655 mutex_unlock(&dst_ctx->mutex);
12656 mutex_unlock(&src_ctx->mutex);
12658 EXPORT_SYMBOL_GPL(perf_pmu_migrate_context);
12660 static void sync_child_event(struct perf_event *child_event)
12662 struct perf_event *parent_event = child_event->parent;
12665 if (child_event->attr.inherit_stat) {
12666 struct task_struct *task = child_event->ctx->task;
12668 if (task && task != TASK_TOMBSTONE)
12669 perf_event_read_event(child_event, task);
12672 child_val = perf_event_count(child_event);
12675 * Add back the child's count to the parent's count:
12677 atomic64_add(child_val, &parent_event->child_count);
12678 atomic64_add(child_event->total_time_enabled,
12679 &parent_event->child_total_time_enabled);
12680 atomic64_add(child_event->total_time_running,
12681 &parent_event->child_total_time_running);
12685 perf_event_exit_event(struct perf_event *event, struct perf_event_context *ctx)
12687 struct perf_event *parent_event = event->parent;
12688 unsigned long detach_flags = 0;
12690 if (parent_event) {
12692 * Do not destroy the 'original' grouping; because of the
12693 * context switch optimization the original events could've
12694 * ended up in a random child task.
12696 * If we were to destroy the original group, all group related
12697 * operations would cease to function properly after this
12698 * random child dies.
12700 * Do destroy all inherited groups, we don't care about those
12701 * and being thorough is better.
12703 detach_flags = DETACH_GROUP | DETACH_CHILD;
12704 mutex_lock(&parent_event->child_mutex);
12707 perf_remove_from_context(event, detach_flags);
12709 raw_spin_lock_irq(&ctx->lock);
12710 if (event->state > PERF_EVENT_STATE_EXIT)
12711 perf_event_set_state(event, PERF_EVENT_STATE_EXIT);
12712 raw_spin_unlock_irq(&ctx->lock);
12715 * Child events can be freed.
12717 if (parent_event) {
12718 mutex_unlock(&parent_event->child_mutex);
12720 * Kick perf_poll() for is_event_hup();
12722 perf_event_wakeup(parent_event);
12724 put_event(parent_event);
12729 * Parent events are governed by their filedesc, retain them.
12731 perf_event_wakeup(event);
12734 static void perf_event_exit_task_context(struct task_struct *child, int ctxn)
12736 struct perf_event_context *child_ctx, *clone_ctx = NULL;
12737 struct perf_event *child_event, *next;
12739 WARN_ON_ONCE(child != current);
12741 child_ctx = perf_pin_task_context(child, ctxn);
12746 * In order to reduce the amount of tricky in ctx tear-down, we hold
12747 * ctx::mutex over the entire thing. This serializes against almost
12748 * everything that wants to access the ctx.
12750 * The exception is sys_perf_event_open() /
12751 * perf_event_create_kernel_count() which does find_get_context()
12752 * without ctx::mutex (it cannot because of the move_group double mutex
12753 * lock thing). See the comments in perf_install_in_context().
12755 mutex_lock(&child_ctx->mutex);
12758 * In a single ctx::lock section, de-schedule the events and detach the
12759 * context from the task such that we cannot ever get it scheduled back
12762 raw_spin_lock_irq(&child_ctx->lock);
12763 task_ctx_sched_out(__get_cpu_context(child_ctx), child_ctx, EVENT_ALL);
12766 * Now that the context is inactive, destroy the task <-> ctx relation
12767 * and mark the context dead.
12769 RCU_INIT_POINTER(child->perf_event_ctxp[ctxn], NULL);
12770 put_ctx(child_ctx); /* cannot be last */
12771 WRITE_ONCE(child_ctx->task, TASK_TOMBSTONE);
12772 put_task_struct(current); /* cannot be last */
12774 clone_ctx = unclone_ctx(child_ctx);
12775 raw_spin_unlock_irq(&child_ctx->lock);
12778 put_ctx(clone_ctx);
12781 * Report the task dead after unscheduling the events so that we
12782 * won't get any samples after PERF_RECORD_EXIT. We can however still
12783 * get a few PERF_RECORD_READ events.
12785 perf_event_task(child, child_ctx, 0);
12787 list_for_each_entry_safe(child_event, next, &child_ctx->event_list, event_entry)
12788 perf_event_exit_event(child_event, child_ctx);
12790 mutex_unlock(&child_ctx->mutex);
12792 put_ctx(child_ctx);
12796 * When a child task exits, feed back event values to parent events.
12798 * Can be called with exec_update_lock held when called from
12799 * setup_new_exec().
12801 void perf_event_exit_task(struct task_struct *child)
12803 struct perf_event *event, *tmp;
12806 mutex_lock(&child->perf_event_mutex);
12807 list_for_each_entry_safe(event, tmp, &child->perf_event_list,
12809 list_del_init(&event->owner_entry);
12812 * Ensure the list deletion is visible before we clear
12813 * the owner, closes a race against perf_release() where
12814 * we need to serialize on the owner->perf_event_mutex.
12816 smp_store_release(&event->owner, NULL);
12818 mutex_unlock(&child->perf_event_mutex);
12820 for_each_task_context_nr(ctxn)
12821 perf_event_exit_task_context(child, ctxn);
12824 * The perf_event_exit_task_context calls perf_event_task
12825 * with child's task_ctx, which generates EXIT events for
12826 * child contexts and sets child->perf_event_ctxp[] to NULL.
12827 * At this point we need to send EXIT events to cpu contexts.
12829 perf_event_task(child, NULL, 0);
12832 static void perf_free_event(struct perf_event *event,
12833 struct perf_event_context *ctx)
12835 struct perf_event *parent = event->parent;
12837 if (WARN_ON_ONCE(!parent))
12840 mutex_lock(&parent->child_mutex);
12841 list_del_init(&event->child_list);
12842 mutex_unlock(&parent->child_mutex);
12846 raw_spin_lock_irq(&ctx->lock);
12847 perf_group_detach(event);
12848 list_del_event(event, ctx);
12849 raw_spin_unlock_irq(&ctx->lock);
12854 * Free a context as created by inheritance by perf_event_init_task() below,
12855 * used by fork() in case of fail.
12857 * Even though the task has never lived, the context and events have been
12858 * exposed through the child_list, so we must take care tearing it all down.
12860 void perf_event_free_task(struct task_struct *task)
12862 struct perf_event_context *ctx;
12863 struct perf_event *event, *tmp;
12866 for_each_task_context_nr(ctxn) {
12867 ctx = task->perf_event_ctxp[ctxn];
12871 mutex_lock(&ctx->mutex);
12872 raw_spin_lock_irq(&ctx->lock);
12874 * Destroy the task <-> ctx relation and mark the context dead.
12876 * This is important because even though the task hasn't been
12877 * exposed yet the context has been (through child_list).
12879 RCU_INIT_POINTER(task->perf_event_ctxp[ctxn], NULL);
12880 WRITE_ONCE(ctx->task, TASK_TOMBSTONE);
12881 put_task_struct(task); /* cannot be last */
12882 raw_spin_unlock_irq(&ctx->lock);
12884 list_for_each_entry_safe(event, tmp, &ctx->event_list, event_entry)
12885 perf_free_event(event, ctx);
12887 mutex_unlock(&ctx->mutex);
12890 * perf_event_release_kernel() could've stolen some of our
12891 * child events and still have them on its free_list. In that
12892 * case we must wait for these events to have been freed (in
12893 * particular all their references to this task must've been
12896 * Without this copy_process() will unconditionally free this
12897 * task (irrespective of its reference count) and
12898 * _free_event()'s put_task_struct(event->hw.target) will be a
12901 * Wait for all events to drop their context reference.
12903 wait_var_event(&ctx->refcount, refcount_read(&ctx->refcount) == 1);
12904 put_ctx(ctx); /* must be last */
12908 void perf_event_delayed_put(struct task_struct *task)
12912 for_each_task_context_nr(ctxn)
12913 WARN_ON_ONCE(task->perf_event_ctxp[ctxn]);
12916 struct file *perf_event_get(unsigned int fd)
12918 struct file *file = fget(fd);
12920 return ERR_PTR(-EBADF);
12922 if (file->f_op != &perf_fops) {
12924 return ERR_PTR(-EBADF);
12930 const struct perf_event *perf_get_event(struct file *file)
12932 if (file->f_op != &perf_fops)
12933 return ERR_PTR(-EINVAL);
12935 return file->private_data;
12938 const struct perf_event_attr *perf_event_attrs(struct perf_event *event)
12941 return ERR_PTR(-EINVAL);
12943 return &event->attr;
12947 * Inherit an event from parent task to child task.
12950 * - valid pointer on success
12951 * - NULL for orphaned events
12952 * - IS_ERR() on error
12954 static struct perf_event *
12955 inherit_event(struct perf_event *parent_event,
12956 struct task_struct *parent,
12957 struct perf_event_context *parent_ctx,
12958 struct task_struct *child,
12959 struct perf_event *group_leader,
12960 struct perf_event_context *child_ctx)
12962 enum perf_event_state parent_state = parent_event->state;
12963 struct perf_event *child_event;
12964 unsigned long flags;
12967 * Instead of creating recursive hierarchies of events,
12968 * we link inherited events back to the original parent,
12969 * which has a filp for sure, which we use as the reference
12972 if (parent_event->parent)
12973 parent_event = parent_event->parent;
12975 child_event = perf_event_alloc(&parent_event->attr,
12978 group_leader, parent_event,
12980 if (IS_ERR(child_event))
12981 return child_event;
12984 if ((child_event->attach_state & PERF_ATTACH_TASK_DATA) &&
12985 !child_ctx->task_ctx_data) {
12986 struct pmu *pmu = child_event->pmu;
12988 child_ctx->task_ctx_data = alloc_task_ctx_data(pmu);
12989 if (!child_ctx->task_ctx_data) {
12990 free_event(child_event);
12991 return ERR_PTR(-ENOMEM);
12996 * is_orphaned_event() and list_add_tail(&parent_event->child_list)
12997 * must be under the same lock in order to serialize against
12998 * perf_event_release_kernel(), such that either we must observe
12999 * is_orphaned_event() or they will observe us on the child_list.
13001 mutex_lock(&parent_event->child_mutex);
13002 if (is_orphaned_event(parent_event) ||
13003 !atomic_long_inc_not_zero(&parent_event->refcount)) {
13004 mutex_unlock(&parent_event->child_mutex);
13005 /* task_ctx_data is freed with child_ctx */
13006 free_event(child_event);
13010 get_ctx(child_ctx);
13013 * Make the child state follow the state of the parent event,
13014 * not its attr.disabled bit. We hold the parent's mutex,
13015 * so we won't race with perf_event_{en, dis}able_family.
13017 if (parent_state >= PERF_EVENT_STATE_INACTIVE)
13018 child_event->state = PERF_EVENT_STATE_INACTIVE;
13020 child_event->state = PERF_EVENT_STATE_OFF;
13022 if (parent_event->attr.freq) {
13023 u64 sample_period = parent_event->hw.sample_period;
13024 struct hw_perf_event *hwc = &child_event->hw;
13026 hwc->sample_period = sample_period;
13027 hwc->last_period = sample_period;
13029 local64_set(&hwc->period_left, sample_period);
13032 child_event->ctx = child_ctx;
13033 child_event->overflow_handler = parent_event->overflow_handler;
13034 child_event->overflow_handler_context
13035 = parent_event->overflow_handler_context;
13038 * Precalculate sample_data sizes
13040 perf_event__header_size(child_event);
13041 perf_event__id_header_size(child_event);
13044 * Link it up in the child's context:
13046 raw_spin_lock_irqsave(&child_ctx->lock, flags);
13047 add_event_to_ctx(child_event, child_ctx);
13048 child_event->attach_state |= PERF_ATTACH_CHILD;
13049 raw_spin_unlock_irqrestore(&child_ctx->lock, flags);
13052 * Link this into the parent event's child list
13054 list_add_tail(&child_event->child_list, &parent_event->child_list);
13055 mutex_unlock(&parent_event->child_mutex);
13057 return child_event;
13061 * Inherits an event group.
13063 * This will quietly suppress orphaned events; !inherit_event() is not an error.
13064 * This matches with perf_event_release_kernel() removing all child events.
13070 static int inherit_group(struct perf_event *parent_event,
13071 struct task_struct *parent,
13072 struct perf_event_context *parent_ctx,
13073 struct task_struct *child,
13074 struct perf_event_context *child_ctx)
13076 struct perf_event *leader;
13077 struct perf_event *sub;
13078 struct perf_event *child_ctr;
13080 leader = inherit_event(parent_event, parent, parent_ctx,
13081 child, NULL, child_ctx);
13082 if (IS_ERR(leader))
13083 return PTR_ERR(leader);
13085 * @leader can be NULL here because of is_orphaned_event(). In this
13086 * case inherit_event() will create individual events, similar to what
13087 * perf_group_detach() would do anyway.
13089 for_each_sibling_event(sub, parent_event) {
13090 child_ctr = inherit_event(sub, parent, parent_ctx,
13091 child, leader, child_ctx);
13092 if (IS_ERR(child_ctr))
13093 return PTR_ERR(child_ctr);
13095 if (sub->aux_event == parent_event && child_ctr &&
13096 !perf_get_aux_event(child_ctr, leader))
13103 * Creates the child task context and tries to inherit the event-group.
13105 * Clears @inherited_all on !attr.inherited or error. Note that we'll leave
13106 * inherited_all set when we 'fail' to inherit an orphaned event; this is
13107 * consistent with perf_event_release_kernel() removing all child events.
13114 inherit_task_group(struct perf_event *event, struct task_struct *parent,
13115 struct perf_event_context *parent_ctx,
13116 struct task_struct *child, int ctxn,
13117 u64 clone_flags, int *inherited_all)
13120 struct perf_event_context *child_ctx;
13122 if (!event->attr.inherit ||
13123 (event->attr.inherit_thread && !(clone_flags & CLONE_THREAD)) ||
13124 /* Do not inherit if sigtrap and signal handlers were cleared. */
13125 (event->attr.sigtrap && (clone_flags & CLONE_CLEAR_SIGHAND))) {
13126 *inherited_all = 0;
13130 child_ctx = child->perf_event_ctxp[ctxn];
13133 * This is executed from the parent task context, so
13134 * inherit events that have been marked for cloning.
13135 * First allocate and initialize a context for the
13138 child_ctx = alloc_perf_context(parent_ctx->pmu, child);
13142 child->perf_event_ctxp[ctxn] = child_ctx;
13145 ret = inherit_group(event, parent, parent_ctx,
13149 *inherited_all = 0;
13155 * Initialize the perf_event context in task_struct
13157 static int perf_event_init_context(struct task_struct *child, int ctxn,
13160 struct perf_event_context *child_ctx, *parent_ctx;
13161 struct perf_event_context *cloned_ctx;
13162 struct perf_event *event;
13163 struct task_struct *parent = current;
13164 int inherited_all = 1;
13165 unsigned long flags;
13168 if (likely(!parent->perf_event_ctxp[ctxn]))
13172 * If the parent's context is a clone, pin it so it won't get
13173 * swapped under us.
13175 parent_ctx = perf_pin_task_context(parent, ctxn);
13180 * No need to check if parent_ctx != NULL here; since we saw
13181 * it non-NULL earlier, the only reason for it to become NULL
13182 * is if we exit, and since we're currently in the middle of
13183 * a fork we can't be exiting at the same time.
13187 * Lock the parent list. No need to lock the child - not PID
13188 * hashed yet and not running, so nobody can access it.
13190 mutex_lock(&parent_ctx->mutex);
13193 * We dont have to disable NMIs - we are only looking at
13194 * the list, not manipulating it:
13196 perf_event_groups_for_each(event, &parent_ctx->pinned_groups) {
13197 ret = inherit_task_group(event, parent, parent_ctx,
13198 child, ctxn, clone_flags,
13205 * We can't hold ctx->lock when iterating the ->flexible_group list due
13206 * to allocations, but we need to prevent rotation because
13207 * rotate_ctx() will change the list from interrupt context.
13209 raw_spin_lock_irqsave(&parent_ctx->lock, flags);
13210 parent_ctx->rotate_disable = 1;
13211 raw_spin_unlock_irqrestore(&parent_ctx->lock, flags);
13213 perf_event_groups_for_each(event, &parent_ctx->flexible_groups) {
13214 ret = inherit_task_group(event, parent, parent_ctx,
13215 child, ctxn, clone_flags,
13221 raw_spin_lock_irqsave(&parent_ctx->lock, flags);
13222 parent_ctx->rotate_disable = 0;
13224 child_ctx = child->perf_event_ctxp[ctxn];
13226 if (child_ctx && inherited_all) {
13228 * Mark the child context as a clone of the parent
13229 * context, or of whatever the parent is a clone of.
13231 * Note that if the parent is a clone, the holding of
13232 * parent_ctx->lock avoids it from being uncloned.
13234 cloned_ctx = parent_ctx->parent_ctx;
13236 child_ctx->parent_ctx = cloned_ctx;
13237 child_ctx->parent_gen = parent_ctx->parent_gen;
13239 child_ctx->parent_ctx = parent_ctx;
13240 child_ctx->parent_gen = parent_ctx->generation;
13242 get_ctx(child_ctx->parent_ctx);
13245 raw_spin_unlock_irqrestore(&parent_ctx->lock, flags);
13247 mutex_unlock(&parent_ctx->mutex);
13249 perf_unpin_context(parent_ctx);
13250 put_ctx(parent_ctx);
13256 * Initialize the perf_event context in task_struct
13258 int perf_event_init_task(struct task_struct *child, u64 clone_flags)
13262 memset(child->perf_event_ctxp, 0, sizeof(child->perf_event_ctxp));
13263 mutex_init(&child->perf_event_mutex);
13264 INIT_LIST_HEAD(&child->perf_event_list);
13266 for_each_task_context_nr(ctxn) {
13267 ret = perf_event_init_context(child, ctxn, clone_flags);
13269 perf_event_free_task(child);
13277 static void __init perf_event_init_all_cpus(void)
13279 struct swevent_htable *swhash;
13282 zalloc_cpumask_var(&perf_online_mask, GFP_KERNEL);
13284 for_each_possible_cpu(cpu) {
13285 swhash = &per_cpu(swevent_htable, cpu);
13286 mutex_init(&swhash->hlist_mutex);
13287 INIT_LIST_HEAD(&per_cpu(active_ctx_list, cpu));
13289 INIT_LIST_HEAD(&per_cpu(pmu_sb_events.list, cpu));
13290 raw_spin_lock_init(&per_cpu(pmu_sb_events.lock, cpu));
13292 #ifdef CONFIG_CGROUP_PERF
13293 INIT_LIST_HEAD(&per_cpu(cgrp_cpuctx_list, cpu));
13295 INIT_LIST_HEAD(&per_cpu(sched_cb_list, cpu));
13299 static void perf_swevent_init_cpu(unsigned int cpu)
13301 struct swevent_htable *swhash = &per_cpu(swevent_htable, cpu);
13303 mutex_lock(&swhash->hlist_mutex);
13304 if (swhash->hlist_refcount > 0 && !swevent_hlist_deref(swhash)) {
13305 struct swevent_hlist *hlist;
13307 hlist = kzalloc_node(sizeof(*hlist), GFP_KERNEL, cpu_to_node(cpu));
13309 rcu_assign_pointer(swhash->swevent_hlist, hlist);
13311 mutex_unlock(&swhash->hlist_mutex);
13314 #if defined CONFIG_HOTPLUG_CPU || defined CONFIG_KEXEC_CORE
13315 static void __perf_event_exit_context(void *__info)
13317 struct perf_event_context *ctx = __info;
13318 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
13319 struct perf_event *event;
13321 raw_spin_lock(&ctx->lock);
13322 ctx_sched_out(ctx, cpuctx, EVENT_TIME);
13323 list_for_each_entry(event, &ctx->event_list, event_entry)
13324 __perf_remove_from_context(event, cpuctx, ctx, (void *)DETACH_GROUP);
13325 raw_spin_unlock(&ctx->lock);
13328 static void perf_event_exit_cpu_context(int cpu)
13330 struct perf_cpu_context *cpuctx;
13331 struct perf_event_context *ctx;
13334 mutex_lock(&pmus_lock);
13335 list_for_each_entry(pmu, &pmus, entry) {
13336 cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
13337 ctx = &cpuctx->ctx;
13339 mutex_lock(&ctx->mutex);
13340 smp_call_function_single(cpu, __perf_event_exit_context, ctx, 1);
13341 cpuctx->online = 0;
13342 mutex_unlock(&ctx->mutex);
13344 cpumask_clear_cpu(cpu, perf_online_mask);
13345 mutex_unlock(&pmus_lock);
13349 static void perf_event_exit_cpu_context(int cpu) { }
13353 int perf_event_init_cpu(unsigned int cpu)
13355 struct perf_cpu_context *cpuctx;
13356 struct perf_event_context *ctx;
13359 perf_swevent_init_cpu(cpu);
13361 mutex_lock(&pmus_lock);
13362 cpumask_set_cpu(cpu, perf_online_mask);
13363 list_for_each_entry(pmu, &pmus, entry) {
13364 cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
13365 ctx = &cpuctx->ctx;
13367 mutex_lock(&ctx->mutex);
13368 cpuctx->online = 1;
13369 mutex_unlock(&ctx->mutex);
13371 mutex_unlock(&pmus_lock);
13376 int perf_event_exit_cpu(unsigned int cpu)
13378 perf_event_exit_cpu_context(cpu);
13383 perf_reboot(struct notifier_block *notifier, unsigned long val, void *v)
13387 for_each_online_cpu(cpu)
13388 perf_event_exit_cpu(cpu);
13394 * Run the perf reboot notifier at the very last possible moment so that
13395 * the generic watchdog code runs as long as possible.
13397 static struct notifier_block perf_reboot_notifier = {
13398 .notifier_call = perf_reboot,
13399 .priority = INT_MIN,
13402 void __init perf_event_init(void)
13406 idr_init(&pmu_idr);
13408 perf_event_init_all_cpus();
13409 init_srcu_struct(&pmus_srcu);
13410 perf_pmu_register(&perf_swevent, "software", PERF_TYPE_SOFTWARE);
13411 perf_pmu_register(&perf_cpu_clock, NULL, -1);
13412 perf_pmu_register(&perf_task_clock, NULL, -1);
13413 perf_tp_register();
13414 perf_event_init_cpu(smp_processor_id());
13415 register_reboot_notifier(&perf_reboot_notifier);
13417 ret = init_hw_breakpoint();
13418 WARN(ret, "hw_breakpoint initialization failed with: %d", ret);
13420 perf_event_cache = KMEM_CACHE(perf_event, SLAB_PANIC);
13423 * Build time assertion that we keep the data_head at the intended
13424 * location. IOW, validation we got the __reserved[] size right.
13426 BUILD_BUG_ON((offsetof(struct perf_event_mmap_page, data_head))
13430 ssize_t perf_event_sysfs_show(struct device *dev, struct device_attribute *attr,
13433 struct perf_pmu_events_attr *pmu_attr =
13434 container_of(attr, struct perf_pmu_events_attr, attr);
13436 if (pmu_attr->event_str)
13437 return sprintf(page, "%s\n", pmu_attr->event_str);
13441 EXPORT_SYMBOL_GPL(perf_event_sysfs_show);
13443 static int __init perf_event_sysfs_init(void)
13448 mutex_lock(&pmus_lock);
13450 ret = bus_register(&pmu_bus);
13454 list_for_each_entry(pmu, &pmus, entry) {
13455 if (!pmu->name || pmu->type < 0)
13458 ret = pmu_dev_alloc(pmu);
13459 WARN(ret, "Failed to register pmu: %s, reason %d\n", pmu->name, ret);
13461 pmu_bus_running = 1;
13465 mutex_unlock(&pmus_lock);
13469 device_initcall(perf_event_sysfs_init);
13471 #ifdef CONFIG_CGROUP_PERF
13472 static struct cgroup_subsys_state *
13473 perf_cgroup_css_alloc(struct cgroup_subsys_state *parent_css)
13475 struct perf_cgroup *jc;
13477 jc = kzalloc(sizeof(*jc), GFP_KERNEL);
13479 return ERR_PTR(-ENOMEM);
13481 jc->info = alloc_percpu(struct perf_cgroup_info);
13484 return ERR_PTR(-ENOMEM);
13490 static void perf_cgroup_css_free(struct cgroup_subsys_state *css)
13492 struct perf_cgroup *jc = container_of(css, struct perf_cgroup, css);
13494 free_percpu(jc->info);
13498 static int perf_cgroup_css_online(struct cgroup_subsys_state *css)
13500 perf_event_cgroup(css->cgroup);
13504 static int __perf_cgroup_move(void *info)
13506 struct task_struct *task = info;
13508 perf_cgroup_switch(task);
13513 static void perf_cgroup_attach(struct cgroup_taskset *tset)
13515 struct task_struct *task;
13516 struct cgroup_subsys_state *css;
13518 cgroup_taskset_for_each(task, css, tset)
13519 task_function_call(task, __perf_cgroup_move, task);
13522 struct cgroup_subsys perf_event_cgrp_subsys = {
13523 .css_alloc = perf_cgroup_css_alloc,
13524 .css_free = perf_cgroup_css_free,
13525 .css_online = perf_cgroup_css_online,
13526 .attach = perf_cgroup_attach,
13528 * Implicitly enable on dfl hierarchy so that perf events can
13529 * always be filtered by cgroup2 path as long as perf_event
13530 * controller is not mounted on a legacy hierarchy.
13532 .implicit_on_dfl = true,
13535 #endif /* CONFIG_CGROUP_PERF */
13537 DEFINE_STATIC_CALL_RET0(perf_snapshot_branch_stack, perf_snapshot_branch_stack_t);