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_GROUP) {
1824 size += sizeof(u64);
1828 event->read_size = size;
1831 static void __perf_event_header_size(struct perf_event *event, u64 sample_type)
1833 struct perf_sample_data *data;
1836 if (sample_type & PERF_SAMPLE_IP)
1837 size += sizeof(data->ip);
1839 if (sample_type & PERF_SAMPLE_ADDR)
1840 size += sizeof(data->addr);
1842 if (sample_type & PERF_SAMPLE_PERIOD)
1843 size += sizeof(data->period);
1845 if (sample_type & PERF_SAMPLE_WEIGHT_TYPE)
1846 size += sizeof(data->weight.full);
1848 if (sample_type & PERF_SAMPLE_READ)
1849 size += event->read_size;
1851 if (sample_type & PERF_SAMPLE_DATA_SRC)
1852 size += sizeof(data->data_src.val);
1854 if (sample_type & PERF_SAMPLE_TRANSACTION)
1855 size += sizeof(data->txn);
1857 if (sample_type & PERF_SAMPLE_PHYS_ADDR)
1858 size += sizeof(data->phys_addr);
1860 if (sample_type & PERF_SAMPLE_CGROUP)
1861 size += sizeof(data->cgroup);
1863 if (sample_type & PERF_SAMPLE_DATA_PAGE_SIZE)
1864 size += sizeof(data->data_page_size);
1866 if (sample_type & PERF_SAMPLE_CODE_PAGE_SIZE)
1867 size += sizeof(data->code_page_size);
1869 event->header_size = size;
1873 * Called at perf_event creation and when events are attached/detached from a
1876 static void perf_event__header_size(struct perf_event *event)
1878 __perf_event_read_size(event,
1879 event->group_leader->nr_siblings);
1880 __perf_event_header_size(event, event->attr.sample_type);
1883 static void perf_event__id_header_size(struct perf_event *event)
1885 struct perf_sample_data *data;
1886 u64 sample_type = event->attr.sample_type;
1889 if (sample_type & PERF_SAMPLE_TID)
1890 size += sizeof(data->tid_entry);
1892 if (sample_type & PERF_SAMPLE_TIME)
1893 size += sizeof(data->time);
1895 if (sample_type & PERF_SAMPLE_IDENTIFIER)
1896 size += sizeof(data->id);
1898 if (sample_type & PERF_SAMPLE_ID)
1899 size += sizeof(data->id);
1901 if (sample_type & PERF_SAMPLE_STREAM_ID)
1902 size += sizeof(data->stream_id);
1904 if (sample_type & PERF_SAMPLE_CPU)
1905 size += sizeof(data->cpu_entry);
1907 event->id_header_size = size;
1910 static bool perf_event_validate_size(struct perf_event *event)
1913 * The values computed here will be over-written when we actually
1916 __perf_event_read_size(event, event->group_leader->nr_siblings + 1);
1917 __perf_event_header_size(event, event->attr.sample_type & ~PERF_SAMPLE_READ);
1918 perf_event__id_header_size(event);
1921 * Sum the lot; should not exceed the 64k limit we have on records.
1922 * Conservative limit to allow for callchains and other variable fields.
1924 if (event->read_size + event->header_size +
1925 event->id_header_size + sizeof(struct perf_event_header) >= 16*1024)
1931 static void perf_group_attach(struct perf_event *event)
1933 struct perf_event *group_leader = event->group_leader, *pos;
1935 lockdep_assert_held(&event->ctx->lock);
1938 * We can have double attach due to group movement in perf_event_open.
1940 if (event->attach_state & PERF_ATTACH_GROUP)
1943 event->attach_state |= PERF_ATTACH_GROUP;
1945 if (group_leader == event)
1948 WARN_ON_ONCE(group_leader->ctx != event->ctx);
1950 group_leader->group_caps &= event->event_caps;
1952 list_add_tail(&event->sibling_list, &group_leader->sibling_list);
1953 group_leader->nr_siblings++;
1955 perf_event__header_size(group_leader);
1957 for_each_sibling_event(pos, group_leader)
1958 perf_event__header_size(pos);
1962 * Remove an event from the lists for its context.
1963 * Must be called with ctx->mutex and ctx->lock held.
1966 list_del_event(struct perf_event *event, struct perf_event_context *ctx)
1968 WARN_ON_ONCE(event->ctx != ctx);
1969 lockdep_assert_held(&ctx->lock);
1972 * We can have double detach due to exit/hot-unplug + close.
1974 if (!(event->attach_state & PERF_ATTACH_CONTEXT))
1977 event->attach_state &= ~PERF_ATTACH_CONTEXT;
1980 if (event->hw.flags & PERF_EVENT_FLAG_USER_READ_CNT)
1982 if (event->attr.inherit_stat)
1985 list_del_rcu(&event->event_entry);
1987 if (event->group_leader == event)
1988 del_event_from_groups(event, ctx);
1991 * If event was in error state, then keep it
1992 * that way, otherwise bogus counts will be
1993 * returned on read(). The only way to get out
1994 * of error state is by explicit re-enabling
1997 if (event->state > PERF_EVENT_STATE_OFF) {
1998 perf_cgroup_event_disable(event, ctx);
1999 perf_event_set_state(event, PERF_EVENT_STATE_OFF);
2006 perf_aux_output_match(struct perf_event *event, struct perf_event *aux_event)
2008 if (!has_aux(aux_event))
2011 if (!event->pmu->aux_output_match)
2014 return event->pmu->aux_output_match(aux_event);
2017 static void put_event(struct perf_event *event);
2018 static void event_sched_out(struct perf_event *event,
2019 struct perf_cpu_context *cpuctx,
2020 struct perf_event_context *ctx);
2022 static void perf_put_aux_event(struct perf_event *event)
2024 struct perf_event_context *ctx = event->ctx;
2025 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
2026 struct perf_event *iter;
2029 * If event uses aux_event tear down the link
2031 if (event->aux_event) {
2032 iter = event->aux_event;
2033 event->aux_event = NULL;
2039 * If the event is an aux_event, tear down all links to
2040 * it from other events.
2042 for_each_sibling_event(iter, event->group_leader) {
2043 if (iter->aux_event != event)
2046 iter->aux_event = NULL;
2050 * If it's ACTIVE, schedule it out and put it into ERROR
2051 * state so that we don't try to schedule it again. Note
2052 * that perf_event_enable() will clear the ERROR status.
2054 event_sched_out(iter, cpuctx, ctx);
2055 perf_event_set_state(event, PERF_EVENT_STATE_ERROR);
2059 static bool perf_need_aux_event(struct perf_event *event)
2061 return !!event->attr.aux_output || !!event->attr.aux_sample_size;
2064 static int perf_get_aux_event(struct perf_event *event,
2065 struct perf_event *group_leader)
2068 * Our group leader must be an aux event if we want to be
2069 * an aux_output. This way, the aux event will precede its
2070 * aux_output events in the group, and therefore will always
2077 * aux_output and aux_sample_size are mutually exclusive.
2079 if (event->attr.aux_output && event->attr.aux_sample_size)
2082 if (event->attr.aux_output &&
2083 !perf_aux_output_match(event, group_leader))
2086 if (event->attr.aux_sample_size && !group_leader->pmu->snapshot_aux)
2089 if (!atomic_long_inc_not_zero(&group_leader->refcount))
2093 * Link aux_outputs to their aux event; this is undone in
2094 * perf_group_detach() by perf_put_aux_event(). When the
2095 * group in torn down, the aux_output events loose their
2096 * link to the aux_event and can't schedule any more.
2098 event->aux_event = group_leader;
2103 static inline struct list_head *get_event_list(struct perf_event *event)
2105 struct perf_event_context *ctx = event->ctx;
2106 return event->attr.pinned ? &ctx->pinned_active : &ctx->flexible_active;
2110 * Events that have PERF_EV_CAP_SIBLING require being part of a group and
2111 * cannot exist on their own, schedule them out and move them into the ERROR
2112 * state. Also see _perf_event_enable(), it will not be able to recover
2115 static inline void perf_remove_sibling_event(struct perf_event *event)
2117 struct perf_event_context *ctx = event->ctx;
2118 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
2120 event_sched_out(event, cpuctx, ctx);
2121 perf_event_set_state(event, PERF_EVENT_STATE_ERROR);
2124 static void perf_group_detach(struct perf_event *event)
2126 struct perf_event *leader = event->group_leader;
2127 struct perf_event *sibling, *tmp;
2128 struct perf_event_context *ctx = event->ctx;
2130 lockdep_assert_held(&ctx->lock);
2133 * We can have double detach due to exit/hot-unplug + close.
2135 if (!(event->attach_state & PERF_ATTACH_GROUP))
2138 event->attach_state &= ~PERF_ATTACH_GROUP;
2140 perf_put_aux_event(event);
2143 * If this is a sibling, remove it from its group.
2145 if (leader != event) {
2146 list_del_init(&event->sibling_list);
2147 event->group_leader->nr_siblings--;
2152 * If this was a group event with sibling events then
2153 * upgrade the siblings to singleton events by adding them
2154 * to whatever list we are on.
2156 list_for_each_entry_safe(sibling, tmp, &event->sibling_list, sibling_list) {
2158 if (sibling->event_caps & PERF_EV_CAP_SIBLING)
2159 perf_remove_sibling_event(sibling);
2161 sibling->group_leader = sibling;
2162 list_del_init(&sibling->sibling_list);
2164 /* Inherit group flags from the previous leader */
2165 sibling->group_caps = event->group_caps;
2167 if (!RB_EMPTY_NODE(&event->group_node)) {
2168 add_event_to_groups(sibling, event->ctx);
2170 if (sibling->state == PERF_EVENT_STATE_ACTIVE)
2171 list_add_tail(&sibling->active_list, get_event_list(sibling));
2174 WARN_ON_ONCE(sibling->ctx != event->ctx);
2178 for_each_sibling_event(tmp, leader)
2179 perf_event__header_size(tmp);
2181 perf_event__header_size(leader);
2184 static void sync_child_event(struct perf_event *child_event);
2186 static void perf_child_detach(struct perf_event *event)
2188 struct perf_event *parent_event = event->parent;
2190 if (!(event->attach_state & PERF_ATTACH_CHILD))
2193 event->attach_state &= ~PERF_ATTACH_CHILD;
2195 if (WARN_ON_ONCE(!parent_event))
2198 lockdep_assert_held(&parent_event->child_mutex);
2200 sync_child_event(event);
2201 list_del_init(&event->child_list);
2204 static bool is_orphaned_event(struct perf_event *event)
2206 return event->state == PERF_EVENT_STATE_DEAD;
2209 static inline int __pmu_filter_match(struct perf_event *event)
2211 struct pmu *pmu = event->pmu;
2212 return pmu->filter_match ? pmu->filter_match(event) : 1;
2216 * Check whether we should attempt to schedule an event group based on
2217 * PMU-specific filtering. An event group can consist of HW and SW events,
2218 * potentially with a SW leader, so we must check all the filters, to
2219 * determine whether a group is schedulable:
2221 static inline int pmu_filter_match(struct perf_event *event)
2223 struct perf_event *sibling;
2225 if (!__pmu_filter_match(event))
2228 for_each_sibling_event(sibling, event) {
2229 if (!__pmu_filter_match(sibling))
2237 event_filter_match(struct perf_event *event)
2239 return (event->cpu == -1 || event->cpu == smp_processor_id()) &&
2240 perf_cgroup_match(event) && pmu_filter_match(event);
2244 event_sched_out(struct perf_event *event,
2245 struct perf_cpu_context *cpuctx,
2246 struct perf_event_context *ctx)
2248 enum perf_event_state state = PERF_EVENT_STATE_INACTIVE;
2250 WARN_ON_ONCE(event->ctx != ctx);
2251 lockdep_assert_held(&ctx->lock);
2253 if (event->state != PERF_EVENT_STATE_ACTIVE)
2257 * Asymmetry; we only schedule events _IN_ through ctx_sched_in(), but
2258 * we can schedule events _OUT_ individually through things like
2259 * __perf_remove_from_context().
2261 list_del_init(&event->active_list);
2263 perf_pmu_disable(event->pmu);
2265 event->pmu->del(event, 0);
2268 if (READ_ONCE(event->pending_disable) >= 0) {
2269 WRITE_ONCE(event->pending_disable, -1);
2270 perf_cgroup_event_disable(event, ctx);
2271 state = PERF_EVENT_STATE_OFF;
2273 perf_event_set_state(event, state);
2275 if (!is_software_event(event))
2276 cpuctx->active_oncpu--;
2277 if (!--ctx->nr_active)
2278 perf_event_ctx_deactivate(ctx);
2279 if (event->attr.freq && event->attr.sample_freq)
2281 if (event->attr.exclusive || !cpuctx->active_oncpu)
2282 cpuctx->exclusive = 0;
2284 perf_pmu_enable(event->pmu);
2288 group_sched_out(struct perf_event *group_event,
2289 struct perf_cpu_context *cpuctx,
2290 struct perf_event_context *ctx)
2292 struct perf_event *event;
2294 if (group_event->state != PERF_EVENT_STATE_ACTIVE)
2297 perf_pmu_disable(ctx->pmu);
2299 event_sched_out(group_event, cpuctx, ctx);
2302 * Schedule out siblings (if any):
2304 for_each_sibling_event(event, group_event)
2305 event_sched_out(event, cpuctx, ctx);
2307 perf_pmu_enable(ctx->pmu);
2310 #define DETACH_GROUP 0x01UL
2311 #define DETACH_CHILD 0x02UL
2314 * Cross CPU call to remove a performance event
2316 * We disable the event on the hardware level first. After that we
2317 * remove it from the context list.
2320 __perf_remove_from_context(struct perf_event *event,
2321 struct perf_cpu_context *cpuctx,
2322 struct perf_event_context *ctx,
2325 unsigned long flags = (unsigned long)info;
2327 if (ctx->is_active & EVENT_TIME) {
2328 update_context_time(ctx);
2329 update_cgrp_time_from_cpuctx(cpuctx, false);
2332 event_sched_out(event, cpuctx, ctx);
2333 if (flags & DETACH_GROUP)
2334 perf_group_detach(event);
2335 if (flags & DETACH_CHILD)
2336 perf_child_detach(event);
2337 list_del_event(event, ctx);
2339 if (!ctx->nr_events && ctx->is_active) {
2340 if (ctx == &cpuctx->ctx)
2341 update_cgrp_time_from_cpuctx(cpuctx, true);
2344 ctx->rotate_necessary = 0;
2346 WARN_ON_ONCE(cpuctx->task_ctx != ctx);
2347 cpuctx->task_ctx = NULL;
2353 * Remove the event from a task's (or a CPU's) list of events.
2355 * If event->ctx is a cloned context, callers must make sure that
2356 * every task struct that event->ctx->task could possibly point to
2357 * remains valid. This is OK when called from perf_release since
2358 * that only calls us on the top-level context, which can't be a clone.
2359 * When called from perf_event_exit_task, it's OK because the
2360 * context has been detached from its task.
2362 static void perf_remove_from_context(struct perf_event *event, unsigned long flags)
2364 struct perf_event_context *ctx = event->ctx;
2366 lockdep_assert_held(&ctx->mutex);
2369 * Because of perf_event_exit_task(), perf_remove_from_context() ought
2370 * to work in the face of TASK_TOMBSTONE, unlike every other
2371 * event_function_call() user.
2373 raw_spin_lock_irq(&ctx->lock);
2375 * Cgroup events are per-cpu events, and must IPI because of
2378 if (!ctx->is_active && !is_cgroup_event(event)) {
2379 __perf_remove_from_context(event, __get_cpu_context(ctx),
2380 ctx, (void *)flags);
2381 raw_spin_unlock_irq(&ctx->lock);
2384 raw_spin_unlock_irq(&ctx->lock);
2386 event_function_call(event, __perf_remove_from_context, (void *)flags);
2390 * Cross CPU call to disable a performance event
2392 static void __perf_event_disable(struct perf_event *event,
2393 struct perf_cpu_context *cpuctx,
2394 struct perf_event_context *ctx,
2397 if (event->state < PERF_EVENT_STATE_INACTIVE)
2400 if (ctx->is_active & EVENT_TIME) {
2401 update_context_time(ctx);
2402 update_cgrp_time_from_event(event);
2405 if (event == event->group_leader)
2406 group_sched_out(event, cpuctx, ctx);
2408 event_sched_out(event, cpuctx, ctx);
2410 perf_event_set_state(event, PERF_EVENT_STATE_OFF);
2411 perf_cgroup_event_disable(event, ctx);
2417 * If event->ctx is a cloned context, callers must make sure that
2418 * every task struct that event->ctx->task could possibly point to
2419 * remains valid. This condition is satisfied when called through
2420 * perf_event_for_each_child or perf_event_for_each because they
2421 * hold the top-level event's child_mutex, so any descendant that
2422 * goes to exit will block in perf_event_exit_event().
2424 * When called from perf_pending_event it's OK because event->ctx
2425 * is the current context on this CPU and preemption is disabled,
2426 * hence we can't get into perf_event_task_sched_out for this context.
2428 static void _perf_event_disable(struct perf_event *event)
2430 struct perf_event_context *ctx = event->ctx;
2432 raw_spin_lock_irq(&ctx->lock);
2433 if (event->state <= PERF_EVENT_STATE_OFF) {
2434 raw_spin_unlock_irq(&ctx->lock);
2437 raw_spin_unlock_irq(&ctx->lock);
2439 event_function_call(event, __perf_event_disable, NULL);
2442 void perf_event_disable_local(struct perf_event *event)
2444 event_function_local(event, __perf_event_disable, NULL);
2448 * Strictly speaking kernel users cannot create groups and therefore this
2449 * interface does not need the perf_event_ctx_lock() magic.
2451 void perf_event_disable(struct perf_event *event)
2453 struct perf_event_context *ctx;
2455 ctx = perf_event_ctx_lock(event);
2456 _perf_event_disable(event);
2457 perf_event_ctx_unlock(event, ctx);
2459 EXPORT_SYMBOL_GPL(perf_event_disable);
2461 void perf_event_disable_inatomic(struct perf_event *event)
2463 WRITE_ONCE(event->pending_disable, smp_processor_id());
2464 /* can fail, see perf_pending_event_disable() */
2465 irq_work_queue(&event->pending);
2468 #define MAX_INTERRUPTS (~0ULL)
2470 static void perf_log_throttle(struct perf_event *event, int enable);
2471 static void perf_log_itrace_start(struct perf_event *event);
2474 event_sched_in(struct perf_event *event,
2475 struct perf_cpu_context *cpuctx,
2476 struct perf_event_context *ctx)
2480 WARN_ON_ONCE(event->ctx != ctx);
2482 lockdep_assert_held(&ctx->lock);
2484 if (event->state <= PERF_EVENT_STATE_OFF)
2487 WRITE_ONCE(event->oncpu, smp_processor_id());
2489 * Order event::oncpu write to happen before the ACTIVE state is
2490 * visible. This allows perf_event_{stop,read}() to observe the correct
2491 * ->oncpu if it sees ACTIVE.
2494 perf_event_set_state(event, PERF_EVENT_STATE_ACTIVE);
2497 * Unthrottle events, since we scheduled we might have missed several
2498 * ticks already, also for a heavily scheduling task there is little
2499 * guarantee it'll get a tick in a timely manner.
2501 if (unlikely(event->hw.interrupts == MAX_INTERRUPTS)) {
2502 perf_log_throttle(event, 1);
2503 event->hw.interrupts = 0;
2506 perf_pmu_disable(event->pmu);
2508 perf_log_itrace_start(event);
2510 if (event->pmu->add(event, PERF_EF_START)) {
2511 perf_event_set_state(event, PERF_EVENT_STATE_INACTIVE);
2517 if (!is_software_event(event))
2518 cpuctx->active_oncpu++;
2519 if (!ctx->nr_active++)
2520 perf_event_ctx_activate(ctx);
2521 if (event->attr.freq && event->attr.sample_freq)
2524 if (event->attr.exclusive)
2525 cpuctx->exclusive = 1;
2528 perf_pmu_enable(event->pmu);
2534 group_sched_in(struct perf_event *group_event,
2535 struct perf_cpu_context *cpuctx,
2536 struct perf_event_context *ctx)
2538 struct perf_event *event, *partial_group = NULL;
2539 struct pmu *pmu = ctx->pmu;
2541 if (group_event->state == PERF_EVENT_STATE_OFF)
2544 pmu->start_txn(pmu, PERF_PMU_TXN_ADD);
2546 if (event_sched_in(group_event, cpuctx, ctx))
2550 * Schedule in siblings as one group (if any):
2552 for_each_sibling_event(event, group_event) {
2553 if (event_sched_in(event, cpuctx, ctx)) {
2554 partial_group = event;
2559 if (!pmu->commit_txn(pmu))
2564 * Groups can be scheduled in as one unit only, so undo any
2565 * partial group before returning:
2566 * The events up to the failed event are scheduled out normally.
2568 for_each_sibling_event(event, group_event) {
2569 if (event == partial_group)
2572 event_sched_out(event, cpuctx, ctx);
2574 event_sched_out(group_event, cpuctx, ctx);
2577 pmu->cancel_txn(pmu);
2582 * Work out whether we can put this event group on the CPU now.
2584 static int group_can_go_on(struct perf_event *event,
2585 struct perf_cpu_context *cpuctx,
2589 * Groups consisting entirely of software events can always go on.
2591 if (event->group_caps & PERF_EV_CAP_SOFTWARE)
2594 * If an exclusive group is already on, no other hardware
2597 if (cpuctx->exclusive)
2600 * If this group is exclusive and there are already
2601 * events on the CPU, it can't go on.
2603 if (event->attr.exclusive && !list_empty(get_event_list(event)))
2606 * Otherwise, try to add it if all previous groups were able
2612 static void add_event_to_ctx(struct perf_event *event,
2613 struct perf_event_context *ctx)
2615 list_add_event(event, ctx);
2616 perf_group_attach(event);
2619 static void ctx_sched_out(struct perf_event_context *ctx,
2620 struct perf_cpu_context *cpuctx,
2621 enum event_type_t event_type);
2623 ctx_sched_in(struct perf_event_context *ctx,
2624 struct perf_cpu_context *cpuctx,
2625 enum event_type_t event_type);
2627 static void task_ctx_sched_out(struct perf_cpu_context *cpuctx,
2628 struct perf_event_context *ctx,
2629 enum event_type_t event_type)
2631 if (!cpuctx->task_ctx)
2634 if (WARN_ON_ONCE(ctx != cpuctx->task_ctx))
2637 ctx_sched_out(ctx, cpuctx, event_type);
2640 static void perf_event_sched_in(struct perf_cpu_context *cpuctx,
2641 struct perf_event_context *ctx)
2643 cpu_ctx_sched_in(cpuctx, EVENT_PINNED);
2645 ctx_sched_in(ctx, cpuctx, EVENT_PINNED);
2646 cpu_ctx_sched_in(cpuctx, EVENT_FLEXIBLE);
2648 ctx_sched_in(ctx, cpuctx, EVENT_FLEXIBLE);
2652 * We want to maintain the following priority of scheduling:
2653 * - CPU pinned (EVENT_CPU | EVENT_PINNED)
2654 * - task pinned (EVENT_PINNED)
2655 * - CPU flexible (EVENT_CPU | EVENT_FLEXIBLE)
2656 * - task flexible (EVENT_FLEXIBLE).
2658 * In order to avoid unscheduling and scheduling back in everything every
2659 * time an event is added, only do it for the groups of equal priority and
2662 * This can be called after a batch operation on task events, in which case
2663 * event_type is a bit mask of the types of events involved. For CPU events,
2664 * event_type is only either EVENT_PINNED or EVENT_FLEXIBLE.
2666 static void ctx_resched(struct perf_cpu_context *cpuctx,
2667 struct perf_event_context *task_ctx,
2668 enum event_type_t event_type)
2670 enum event_type_t ctx_event_type;
2671 bool cpu_event = !!(event_type & EVENT_CPU);
2674 * If pinned groups are involved, flexible groups also need to be
2677 if (event_type & EVENT_PINNED)
2678 event_type |= EVENT_FLEXIBLE;
2680 ctx_event_type = event_type & EVENT_ALL;
2682 perf_pmu_disable(cpuctx->ctx.pmu);
2684 task_ctx_sched_out(cpuctx, task_ctx, event_type);
2687 * Decide which cpu ctx groups to schedule out based on the types
2688 * of events that caused rescheduling:
2689 * - EVENT_CPU: schedule out corresponding groups;
2690 * - EVENT_PINNED task events: schedule out EVENT_FLEXIBLE groups;
2691 * - otherwise, do nothing more.
2694 cpu_ctx_sched_out(cpuctx, ctx_event_type);
2695 else if (ctx_event_type & EVENT_PINNED)
2696 cpu_ctx_sched_out(cpuctx, EVENT_FLEXIBLE);
2698 perf_event_sched_in(cpuctx, task_ctx);
2699 perf_pmu_enable(cpuctx->ctx.pmu);
2702 void perf_pmu_resched(struct pmu *pmu)
2704 struct perf_cpu_context *cpuctx = this_cpu_ptr(pmu->pmu_cpu_context);
2705 struct perf_event_context *task_ctx = cpuctx->task_ctx;
2707 perf_ctx_lock(cpuctx, task_ctx);
2708 ctx_resched(cpuctx, task_ctx, EVENT_ALL|EVENT_CPU);
2709 perf_ctx_unlock(cpuctx, task_ctx);
2713 * Cross CPU call to install and enable a performance event
2715 * Very similar to remote_function() + event_function() but cannot assume that
2716 * things like ctx->is_active and cpuctx->task_ctx are set.
2718 static int __perf_install_in_context(void *info)
2720 struct perf_event *event = info;
2721 struct perf_event_context *ctx = event->ctx;
2722 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
2723 struct perf_event_context *task_ctx = cpuctx->task_ctx;
2724 bool reprogram = true;
2727 raw_spin_lock(&cpuctx->ctx.lock);
2729 raw_spin_lock(&ctx->lock);
2732 reprogram = (ctx->task == current);
2735 * If the task is running, it must be running on this CPU,
2736 * otherwise we cannot reprogram things.
2738 * If its not running, we don't care, ctx->lock will
2739 * serialize against it becoming runnable.
2741 if (task_curr(ctx->task) && !reprogram) {
2746 WARN_ON_ONCE(reprogram && cpuctx->task_ctx && cpuctx->task_ctx != ctx);
2747 } else if (task_ctx) {
2748 raw_spin_lock(&task_ctx->lock);
2751 #ifdef CONFIG_CGROUP_PERF
2752 if (event->state > PERF_EVENT_STATE_OFF && is_cgroup_event(event)) {
2754 * If the current cgroup doesn't match the event's
2755 * cgroup, we should not try to schedule it.
2757 struct perf_cgroup *cgrp = perf_cgroup_from_task(current, ctx);
2758 reprogram = cgroup_is_descendant(cgrp->css.cgroup,
2759 event->cgrp->css.cgroup);
2764 ctx_sched_out(ctx, cpuctx, EVENT_TIME);
2765 add_event_to_ctx(event, ctx);
2766 ctx_resched(cpuctx, task_ctx, get_event_type(event));
2768 add_event_to_ctx(event, ctx);
2772 perf_ctx_unlock(cpuctx, task_ctx);
2777 static bool exclusive_event_installable(struct perf_event *event,
2778 struct perf_event_context *ctx);
2781 * Attach a performance event to a context.
2783 * Very similar to event_function_call, see comment there.
2786 perf_install_in_context(struct perf_event_context *ctx,
2787 struct perf_event *event,
2790 struct task_struct *task = READ_ONCE(ctx->task);
2792 lockdep_assert_held(&ctx->mutex);
2794 WARN_ON_ONCE(!exclusive_event_installable(event, ctx));
2796 if (event->cpu != -1)
2800 * Ensures that if we can observe event->ctx, both the event and ctx
2801 * will be 'complete'. See perf_iterate_sb_cpu().
2803 smp_store_release(&event->ctx, ctx);
2806 * perf_event_attr::disabled events will not run and can be initialized
2807 * without IPI. Except when this is the first event for the context, in
2808 * that case we need the magic of the IPI to set ctx->is_active.
2809 * Similarly, cgroup events for the context also needs the IPI to
2810 * manipulate the cgrp_cpuctx_list.
2812 * The IOC_ENABLE that is sure to follow the creation of a disabled
2813 * event will issue the IPI and reprogram the hardware.
2815 if (__perf_effective_state(event) == PERF_EVENT_STATE_OFF &&
2816 ctx->nr_events && !is_cgroup_event(event)) {
2817 raw_spin_lock_irq(&ctx->lock);
2818 if (ctx->task == TASK_TOMBSTONE) {
2819 raw_spin_unlock_irq(&ctx->lock);
2822 add_event_to_ctx(event, ctx);
2823 raw_spin_unlock_irq(&ctx->lock);
2828 cpu_function_call(cpu, __perf_install_in_context, event);
2833 * Should not happen, we validate the ctx is still alive before calling.
2835 if (WARN_ON_ONCE(task == TASK_TOMBSTONE))
2839 * Installing events is tricky because we cannot rely on ctx->is_active
2840 * to be set in case this is the nr_events 0 -> 1 transition.
2842 * Instead we use task_curr(), which tells us if the task is running.
2843 * However, since we use task_curr() outside of rq::lock, we can race
2844 * against the actual state. This means the result can be wrong.
2846 * If we get a false positive, we retry, this is harmless.
2848 * If we get a false negative, things are complicated. If we are after
2849 * perf_event_context_sched_in() ctx::lock will serialize us, and the
2850 * value must be correct. If we're before, it doesn't matter since
2851 * perf_event_context_sched_in() will program the counter.
2853 * However, this hinges on the remote context switch having observed
2854 * our task->perf_event_ctxp[] store, such that it will in fact take
2855 * ctx::lock in perf_event_context_sched_in().
2857 * We do this by task_function_call(), if the IPI fails to hit the task
2858 * we know any future context switch of task must see the
2859 * perf_event_ctpx[] store.
2863 * This smp_mb() orders the task->perf_event_ctxp[] store with the
2864 * task_cpu() load, such that if the IPI then does not find the task
2865 * running, a future context switch of that task must observe the
2870 if (!task_function_call(task, __perf_install_in_context, event))
2873 raw_spin_lock_irq(&ctx->lock);
2875 if (WARN_ON_ONCE(task == TASK_TOMBSTONE)) {
2877 * Cannot happen because we already checked above (which also
2878 * cannot happen), and we hold ctx->mutex, which serializes us
2879 * against perf_event_exit_task_context().
2881 raw_spin_unlock_irq(&ctx->lock);
2885 * If the task is not running, ctx->lock will avoid it becoming so,
2886 * thus we can safely install the event.
2888 if (task_curr(task)) {
2889 raw_spin_unlock_irq(&ctx->lock);
2892 add_event_to_ctx(event, ctx);
2893 raw_spin_unlock_irq(&ctx->lock);
2897 * Cross CPU call to enable a performance event
2899 static void __perf_event_enable(struct perf_event *event,
2900 struct perf_cpu_context *cpuctx,
2901 struct perf_event_context *ctx,
2904 struct perf_event *leader = event->group_leader;
2905 struct perf_event_context *task_ctx;
2907 if (event->state >= PERF_EVENT_STATE_INACTIVE ||
2908 event->state <= PERF_EVENT_STATE_ERROR)
2912 ctx_sched_out(ctx, cpuctx, EVENT_TIME);
2914 perf_event_set_state(event, PERF_EVENT_STATE_INACTIVE);
2915 perf_cgroup_event_enable(event, ctx);
2917 if (!ctx->is_active)
2920 if (!event_filter_match(event)) {
2921 ctx_sched_in(ctx, cpuctx, EVENT_TIME);
2926 * If the event is in a group and isn't the group leader,
2927 * then don't put it on unless the group is on.
2929 if (leader != event && leader->state != PERF_EVENT_STATE_ACTIVE) {
2930 ctx_sched_in(ctx, cpuctx, EVENT_TIME);
2934 task_ctx = cpuctx->task_ctx;
2936 WARN_ON_ONCE(task_ctx != ctx);
2938 ctx_resched(cpuctx, task_ctx, get_event_type(event));
2944 * If event->ctx is a cloned context, callers must make sure that
2945 * every task struct that event->ctx->task could possibly point to
2946 * remains valid. This condition is satisfied when called through
2947 * perf_event_for_each_child or perf_event_for_each as described
2948 * for perf_event_disable.
2950 static void _perf_event_enable(struct perf_event *event)
2952 struct perf_event_context *ctx = event->ctx;
2954 raw_spin_lock_irq(&ctx->lock);
2955 if (event->state >= PERF_EVENT_STATE_INACTIVE ||
2956 event->state < PERF_EVENT_STATE_ERROR) {
2958 raw_spin_unlock_irq(&ctx->lock);
2963 * If the event is in error state, clear that first.
2965 * That way, if we see the event in error state below, we know that it
2966 * has gone back into error state, as distinct from the task having
2967 * been scheduled away before the cross-call arrived.
2969 if (event->state == PERF_EVENT_STATE_ERROR) {
2971 * Detached SIBLING events cannot leave ERROR state.
2973 if (event->event_caps & PERF_EV_CAP_SIBLING &&
2974 event->group_leader == event)
2977 event->state = PERF_EVENT_STATE_OFF;
2979 raw_spin_unlock_irq(&ctx->lock);
2981 event_function_call(event, __perf_event_enable, NULL);
2985 * See perf_event_disable();
2987 void perf_event_enable(struct perf_event *event)
2989 struct perf_event_context *ctx;
2991 ctx = perf_event_ctx_lock(event);
2992 _perf_event_enable(event);
2993 perf_event_ctx_unlock(event, ctx);
2995 EXPORT_SYMBOL_GPL(perf_event_enable);
2997 struct stop_event_data {
2998 struct perf_event *event;
2999 unsigned int restart;
3002 static int __perf_event_stop(void *info)
3004 struct stop_event_data *sd = info;
3005 struct perf_event *event = sd->event;
3007 /* if it's already INACTIVE, do nothing */
3008 if (READ_ONCE(event->state) != PERF_EVENT_STATE_ACTIVE)
3011 /* matches smp_wmb() in event_sched_in() */
3015 * There is a window with interrupts enabled before we get here,
3016 * so we need to check again lest we try to stop another CPU's event.
3018 if (READ_ONCE(event->oncpu) != smp_processor_id())
3021 event->pmu->stop(event, PERF_EF_UPDATE);
3024 * May race with the actual stop (through perf_pmu_output_stop()),
3025 * but it is only used for events with AUX ring buffer, and such
3026 * events will refuse to restart because of rb::aux_mmap_count==0,
3027 * see comments in perf_aux_output_begin().
3029 * Since this is happening on an event-local CPU, no trace is lost
3033 event->pmu->start(event, 0);
3038 static int perf_event_stop(struct perf_event *event, int restart)
3040 struct stop_event_data sd = {
3047 if (READ_ONCE(event->state) != PERF_EVENT_STATE_ACTIVE)
3050 /* matches smp_wmb() in event_sched_in() */
3054 * We only want to restart ACTIVE events, so if the event goes
3055 * inactive here (event->oncpu==-1), there's nothing more to do;
3056 * fall through with ret==-ENXIO.
3058 ret = cpu_function_call(READ_ONCE(event->oncpu),
3059 __perf_event_stop, &sd);
3060 } while (ret == -EAGAIN);
3066 * In order to contain the amount of racy and tricky in the address filter
3067 * configuration management, it is a two part process:
3069 * (p1) when userspace mappings change as a result of (1) or (2) or (3) below,
3070 * we update the addresses of corresponding vmas in
3071 * event::addr_filter_ranges array and bump the event::addr_filters_gen;
3072 * (p2) when an event is scheduled in (pmu::add), it calls
3073 * perf_event_addr_filters_sync() which calls pmu::addr_filters_sync()
3074 * if the generation has changed since the previous call.
3076 * If (p1) happens while the event is active, we restart it to force (p2).
3078 * (1) perf_addr_filters_apply(): adjusting filters' offsets based on
3079 * pre-existing mappings, called once when new filters arrive via SET_FILTER
3081 * (2) perf_addr_filters_adjust(): adjusting filters' offsets based on newly
3082 * registered mapping, called for every new mmap(), with mm::mmap_lock down
3084 * (3) perf_event_addr_filters_exec(): clearing filters' offsets in the process
3087 void perf_event_addr_filters_sync(struct perf_event *event)
3089 struct perf_addr_filters_head *ifh = perf_event_addr_filters(event);
3091 if (!has_addr_filter(event))
3094 raw_spin_lock(&ifh->lock);
3095 if (event->addr_filters_gen != event->hw.addr_filters_gen) {
3096 event->pmu->addr_filters_sync(event);
3097 event->hw.addr_filters_gen = event->addr_filters_gen;
3099 raw_spin_unlock(&ifh->lock);
3101 EXPORT_SYMBOL_GPL(perf_event_addr_filters_sync);
3103 static int _perf_event_refresh(struct perf_event *event, int refresh)
3106 * not supported on inherited events
3108 if (event->attr.inherit || !is_sampling_event(event))
3111 atomic_add(refresh, &event->event_limit);
3112 _perf_event_enable(event);
3118 * See perf_event_disable()
3120 int perf_event_refresh(struct perf_event *event, int refresh)
3122 struct perf_event_context *ctx;
3125 ctx = perf_event_ctx_lock(event);
3126 ret = _perf_event_refresh(event, refresh);
3127 perf_event_ctx_unlock(event, ctx);
3131 EXPORT_SYMBOL_GPL(perf_event_refresh);
3133 static int perf_event_modify_breakpoint(struct perf_event *bp,
3134 struct perf_event_attr *attr)
3138 _perf_event_disable(bp);
3140 err = modify_user_hw_breakpoint_check(bp, attr, true);
3142 if (!bp->attr.disabled)
3143 _perf_event_enable(bp);
3149 * Copy event-type-independent attributes that may be modified.
3151 static void perf_event_modify_copy_attr(struct perf_event_attr *to,
3152 const struct perf_event_attr *from)
3154 to->sig_data = from->sig_data;
3157 static int perf_event_modify_attr(struct perf_event *event,
3158 struct perf_event_attr *attr)
3160 int (*func)(struct perf_event *, struct perf_event_attr *);
3161 struct perf_event *child;
3164 if (event->attr.type != attr->type)
3167 switch (event->attr.type) {
3168 case PERF_TYPE_BREAKPOINT:
3169 func = perf_event_modify_breakpoint;
3172 /* Place holder for future additions. */
3176 WARN_ON_ONCE(event->ctx->parent_ctx);
3178 mutex_lock(&event->child_mutex);
3180 * Event-type-independent attributes must be copied before event-type
3181 * modification, which will validate that final attributes match the
3182 * source attributes after all relevant attributes have been copied.
3184 perf_event_modify_copy_attr(&event->attr, attr);
3185 err = func(event, attr);
3188 list_for_each_entry(child, &event->child_list, child_list) {
3189 perf_event_modify_copy_attr(&child->attr, attr);
3190 err = func(child, attr);
3195 mutex_unlock(&event->child_mutex);
3199 static void ctx_sched_out(struct perf_event_context *ctx,
3200 struct perf_cpu_context *cpuctx,
3201 enum event_type_t event_type)
3203 struct perf_event *event, *tmp;
3204 int is_active = ctx->is_active;
3206 lockdep_assert_held(&ctx->lock);
3208 if (likely(!ctx->nr_events)) {
3210 * See __perf_remove_from_context().
3212 WARN_ON_ONCE(ctx->is_active);
3214 WARN_ON_ONCE(cpuctx->task_ctx);
3219 * Always update time if it was set; not only when it changes.
3220 * Otherwise we can 'forget' to update time for any but the last
3221 * context we sched out. For example:
3223 * ctx_sched_out(.event_type = EVENT_FLEXIBLE)
3224 * ctx_sched_out(.event_type = EVENT_PINNED)
3226 * would only update time for the pinned events.
3228 if (is_active & EVENT_TIME) {
3229 /* update (and stop) ctx time */
3230 update_context_time(ctx);
3231 update_cgrp_time_from_cpuctx(cpuctx, ctx == &cpuctx->ctx);
3233 * CPU-release for the below ->is_active store,
3234 * see __load_acquire() in perf_event_time_now()
3239 ctx->is_active &= ~event_type;
3240 if (!(ctx->is_active & EVENT_ALL))
3244 WARN_ON_ONCE(cpuctx->task_ctx != ctx);
3245 if (!ctx->is_active)
3246 cpuctx->task_ctx = NULL;
3249 is_active ^= ctx->is_active; /* changed bits */
3251 if (!ctx->nr_active || !(is_active & EVENT_ALL))
3254 perf_pmu_disable(ctx->pmu);
3255 if (is_active & EVENT_PINNED) {
3256 list_for_each_entry_safe(event, tmp, &ctx->pinned_active, active_list)
3257 group_sched_out(event, cpuctx, ctx);
3260 if (is_active & EVENT_FLEXIBLE) {
3261 list_for_each_entry_safe(event, tmp, &ctx->flexible_active, active_list)
3262 group_sched_out(event, cpuctx, ctx);
3265 * Since we cleared EVENT_FLEXIBLE, also clear
3266 * rotate_necessary, is will be reset by
3267 * ctx_flexible_sched_in() when needed.
3269 ctx->rotate_necessary = 0;
3271 perf_pmu_enable(ctx->pmu);
3275 * Test whether two contexts are equivalent, i.e. whether they have both been
3276 * cloned from the same version of the same context.
3278 * Equivalence is measured using a generation number in the context that is
3279 * incremented on each modification to it; see unclone_ctx(), list_add_event()
3280 * and list_del_event().
3282 static int context_equiv(struct perf_event_context *ctx1,
3283 struct perf_event_context *ctx2)
3285 lockdep_assert_held(&ctx1->lock);
3286 lockdep_assert_held(&ctx2->lock);
3288 /* Pinning disables the swap optimization */
3289 if (ctx1->pin_count || ctx2->pin_count)
3292 /* If ctx1 is the parent of ctx2 */
3293 if (ctx1 == ctx2->parent_ctx && ctx1->generation == ctx2->parent_gen)
3296 /* If ctx2 is the parent of ctx1 */
3297 if (ctx1->parent_ctx == ctx2 && ctx1->parent_gen == ctx2->generation)
3301 * If ctx1 and ctx2 have the same parent; we flatten the parent
3302 * hierarchy, see perf_event_init_context().
3304 if (ctx1->parent_ctx && ctx1->parent_ctx == ctx2->parent_ctx &&
3305 ctx1->parent_gen == ctx2->parent_gen)
3312 static void __perf_event_sync_stat(struct perf_event *event,
3313 struct perf_event *next_event)
3317 if (!event->attr.inherit_stat)
3321 * Update the event value, we cannot use perf_event_read()
3322 * because we're in the middle of a context switch and have IRQs
3323 * disabled, which upsets smp_call_function_single(), however
3324 * we know the event must be on the current CPU, therefore we
3325 * don't need to use it.
3327 if (event->state == PERF_EVENT_STATE_ACTIVE)
3328 event->pmu->read(event);
3330 perf_event_update_time(event);
3333 * In order to keep per-task stats reliable we need to flip the event
3334 * values when we flip the contexts.
3336 value = local64_read(&next_event->count);
3337 value = local64_xchg(&event->count, value);
3338 local64_set(&next_event->count, value);
3340 swap(event->total_time_enabled, next_event->total_time_enabled);
3341 swap(event->total_time_running, next_event->total_time_running);
3344 * Since we swizzled the values, update the user visible data too.
3346 perf_event_update_userpage(event);
3347 perf_event_update_userpage(next_event);
3350 static void perf_event_sync_stat(struct perf_event_context *ctx,
3351 struct perf_event_context *next_ctx)
3353 struct perf_event *event, *next_event;
3358 update_context_time(ctx);
3360 event = list_first_entry(&ctx->event_list,
3361 struct perf_event, event_entry);
3363 next_event = list_first_entry(&next_ctx->event_list,
3364 struct perf_event, event_entry);
3366 while (&event->event_entry != &ctx->event_list &&
3367 &next_event->event_entry != &next_ctx->event_list) {
3369 __perf_event_sync_stat(event, next_event);
3371 event = list_next_entry(event, event_entry);
3372 next_event = list_next_entry(next_event, event_entry);
3376 static void perf_event_context_sched_out(struct task_struct *task, int ctxn,
3377 struct task_struct *next)
3379 struct perf_event_context *ctx = task->perf_event_ctxp[ctxn];
3380 struct perf_event_context *next_ctx;
3381 struct perf_event_context *parent, *next_parent;
3382 struct perf_cpu_context *cpuctx;
3390 cpuctx = __get_cpu_context(ctx);
3391 if (!cpuctx->task_ctx)
3395 next_ctx = next->perf_event_ctxp[ctxn];
3399 parent = rcu_dereference(ctx->parent_ctx);
3400 next_parent = rcu_dereference(next_ctx->parent_ctx);
3402 /* If neither context have a parent context; they cannot be clones. */
3403 if (!parent && !next_parent)
3406 if (next_parent == ctx || next_ctx == parent || next_parent == parent) {
3408 * Looks like the two contexts are clones, so we might be
3409 * able to optimize the context switch. We lock both
3410 * contexts and check that they are clones under the
3411 * lock (including re-checking that neither has been
3412 * uncloned in the meantime). It doesn't matter which
3413 * order we take the locks because no other cpu could
3414 * be trying to lock both of these tasks.
3416 raw_spin_lock(&ctx->lock);
3417 raw_spin_lock_nested(&next_ctx->lock, SINGLE_DEPTH_NESTING);
3418 if (context_equiv(ctx, next_ctx)) {
3420 WRITE_ONCE(ctx->task, next);
3421 WRITE_ONCE(next_ctx->task, task);
3423 perf_pmu_disable(pmu);
3425 if (cpuctx->sched_cb_usage && pmu->sched_task)
3426 pmu->sched_task(ctx, false);
3429 * PMU specific parts of task perf context can require
3430 * additional synchronization. As an example of such
3431 * synchronization see implementation details of Intel
3432 * LBR call stack data profiling;
3434 if (pmu->swap_task_ctx)
3435 pmu->swap_task_ctx(ctx, next_ctx);
3437 swap(ctx->task_ctx_data, next_ctx->task_ctx_data);
3439 perf_pmu_enable(pmu);
3442 * RCU_INIT_POINTER here is safe because we've not
3443 * modified the ctx and the above modification of
3444 * ctx->task and ctx->task_ctx_data are immaterial
3445 * since those values are always verified under
3446 * ctx->lock which we're now holding.
3448 RCU_INIT_POINTER(task->perf_event_ctxp[ctxn], next_ctx);
3449 RCU_INIT_POINTER(next->perf_event_ctxp[ctxn], ctx);
3453 perf_event_sync_stat(ctx, next_ctx);
3455 raw_spin_unlock(&next_ctx->lock);
3456 raw_spin_unlock(&ctx->lock);
3462 raw_spin_lock(&ctx->lock);
3463 perf_pmu_disable(pmu);
3465 if (cpuctx->sched_cb_usage && pmu->sched_task)
3466 pmu->sched_task(ctx, false);
3467 task_ctx_sched_out(cpuctx, ctx, EVENT_ALL);
3469 perf_pmu_enable(pmu);
3470 raw_spin_unlock(&ctx->lock);
3474 static DEFINE_PER_CPU(struct list_head, sched_cb_list);
3476 void perf_sched_cb_dec(struct pmu *pmu)
3478 struct perf_cpu_context *cpuctx = this_cpu_ptr(pmu->pmu_cpu_context);
3480 this_cpu_dec(perf_sched_cb_usages);
3482 if (!--cpuctx->sched_cb_usage)
3483 list_del(&cpuctx->sched_cb_entry);
3487 void perf_sched_cb_inc(struct pmu *pmu)
3489 struct perf_cpu_context *cpuctx = this_cpu_ptr(pmu->pmu_cpu_context);
3491 if (!cpuctx->sched_cb_usage++)
3492 list_add(&cpuctx->sched_cb_entry, this_cpu_ptr(&sched_cb_list));
3494 this_cpu_inc(perf_sched_cb_usages);
3498 * This function provides the context switch callback to the lower code
3499 * layer. It is invoked ONLY when the context switch callback is enabled.
3501 * This callback is relevant even to per-cpu events; for example multi event
3502 * PEBS requires this to provide PID/TID information. This requires we flush
3503 * all queued PEBS records before we context switch to a new task.
3505 static void __perf_pmu_sched_task(struct perf_cpu_context *cpuctx, bool sched_in)
3509 pmu = cpuctx->ctx.pmu; /* software PMUs will not have sched_task */
3511 if (WARN_ON_ONCE(!pmu->sched_task))
3514 perf_ctx_lock(cpuctx, cpuctx->task_ctx);
3515 perf_pmu_disable(pmu);
3517 pmu->sched_task(cpuctx->task_ctx, sched_in);
3519 perf_pmu_enable(pmu);
3520 perf_ctx_unlock(cpuctx, cpuctx->task_ctx);
3523 static void perf_pmu_sched_task(struct task_struct *prev,
3524 struct task_struct *next,
3527 struct perf_cpu_context *cpuctx;
3532 list_for_each_entry(cpuctx, this_cpu_ptr(&sched_cb_list), sched_cb_entry) {
3533 /* will be handled in perf_event_context_sched_in/out */
3534 if (cpuctx->task_ctx)
3537 __perf_pmu_sched_task(cpuctx, sched_in);
3541 static void perf_event_switch(struct task_struct *task,
3542 struct task_struct *next_prev, bool sched_in);
3544 #define for_each_task_context_nr(ctxn) \
3545 for ((ctxn) = 0; (ctxn) < perf_nr_task_contexts; (ctxn)++)
3548 * Called from scheduler to remove the events of the current task,
3549 * with interrupts disabled.
3551 * We stop each event and update the event value in event->count.
3553 * This does not protect us against NMI, but disable()
3554 * sets the disabled bit in the control field of event _before_
3555 * accessing the event control register. If a NMI hits, then it will
3556 * not restart the event.
3558 void __perf_event_task_sched_out(struct task_struct *task,
3559 struct task_struct *next)
3563 if (__this_cpu_read(perf_sched_cb_usages))
3564 perf_pmu_sched_task(task, next, false);
3566 if (atomic_read(&nr_switch_events))
3567 perf_event_switch(task, next, false);
3569 for_each_task_context_nr(ctxn)
3570 perf_event_context_sched_out(task, ctxn, next);
3573 * if cgroup events exist on this CPU, then we need
3574 * to check if we have to switch out PMU state.
3575 * cgroup event are system-wide mode only
3577 if (atomic_read(this_cpu_ptr(&perf_cgroup_events)))
3578 perf_cgroup_switch(next);
3582 * Called with IRQs disabled
3584 static void cpu_ctx_sched_out(struct perf_cpu_context *cpuctx,
3585 enum event_type_t event_type)
3587 ctx_sched_out(&cpuctx->ctx, cpuctx, event_type);
3590 static bool perf_less_group_idx(const void *l, const void *r)
3592 const struct perf_event *le = *(const struct perf_event **)l;
3593 const struct perf_event *re = *(const struct perf_event **)r;
3595 return le->group_index < re->group_index;
3598 static void swap_ptr(void *l, void *r)
3600 void **lp = l, **rp = r;
3605 static const struct min_heap_callbacks perf_min_heap = {
3606 .elem_size = sizeof(struct perf_event *),
3607 .less = perf_less_group_idx,
3611 static void __heap_add(struct min_heap *heap, struct perf_event *event)
3613 struct perf_event **itrs = heap->data;
3616 itrs[heap->nr] = event;
3621 static noinline int visit_groups_merge(struct perf_cpu_context *cpuctx,
3622 struct perf_event_groups *groups, int cpu,
3623 int (*func)(struct perf_event *, void *),
3626 #ifdef CONFIG_CGROUP_PERF
3627 struct cgroup_subsys_state *css = NULL;
3629 /* Space for per CPU and/or any CPU event iterators. */
3630 struct perf_event *itrs[2];
3631 struct min_heap event_heap;
3632 struct perf_event **evt;
3636 event_heap = (struct min_heap){
3637 .data = cpuctx->heap,
3639 .size = cpuctx->heap_size,
3642 lockdep_assert_held(&cpuctx->ctx.lock);
3644 #ifdef CONFIG_CGROUP_PERF
3646 css = &cpuctx->cgrp->css;
3649 event_heap = (struct min_heap){
3652 .size = ARRAY_SIZE(itrs),
3654 /* Events not within a CPU context may be on any CPU. */
3655 __heap_add(&event_heap, perf_event_groups_first(groups, -1, NULL));
3657 evt = event_heap.data;
3659 __heap_add(&event_heap, perf_event_groups_first(groups, cpu, NULL));
3661 #ifdef CONFIG_CGROUP_PERF
3662 for (; css; css = css->parent)
3663 __heap_add(&event_heap, perf_event_groups_first(groups, cpu, css->cgroup));
3666 min_heapify_all(&event_heap, &perf_min_heap);
3668 while (event_heap.nr) {
3669 ret = func(*evt, data);
3673 *evt = perf_event_groups_next(*evt);
3675 min_heapify(&event_heap, 0, &perf_min_heap);
3677 min_heap_pop(&event_heap, &perf_min_heap);
3684 * Because the userpage is strictly per-event (there is no concept of context,
3685 * so there cannot be a context indirection), every userpage must be updated
3686 * when context time starts :-(
3688 * IOW, we must not miss EVENT_TIME edges.
3690 static inline bool event_update_userpage(struct perf_event *event)
3692 if (likely(!atomic_read(&event->mmap_count)))
3695 perf_event_update_time(event);
3696 perf_event_update_userpage(event);
3701 static inline void group_update_userpage(struct perf_event *group_event)
3703 struct perf_event *event;
3705 if (!event_update_userpage(group_event))
3708 for_each_sibling_event(event, group_event)
3709 event_update_userpage(event);
3712 static int merge_sched_in(struct perf_event *event, void *data)
3714 struct perf_event_context *ctx = event->ctx;
3715 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
3716 int *can_add_hw = data;
3718 if (event->state <= PERF_EVENT_STATE_OFF)
3721 if (!event_filter_match(event))
3724 if (group_can_go_on(event, cpuctx, *can_add_hw)) {
3725 if (!group_sched_in(event, cpuctx, ctx))
3726 list_add_tail(&event->active_list, get_event_list(event));
3729 if (event->state == PERF_EVENT_STATE_INACTIVE) {
3731 if (event->attr.pinned) {
3732 perf_cgroup_event_disable(event, ctx);
3733 perf_event_set_state(event, PERF_EVENT_STATE_ERROR);
3735 ctx->rotate_necessary = 1;
3736 perf_mux_hrtimer_restart(cpuctx);
3737 group_update_userpage(event);
3745 ctx_pinned_sched_in(struct perf_event_context *ctx,
3746 struct perf_cpu_context *cpuctx)
3750 if (ctx != &cpuctx->ctx)
3753 visit_groups_merge(cpuctx, &ctx->pinned_groups,
3755 merge_sched_in, &can_add_hw);
3759 ctx_flexible_sched_in(struct perf_event_context *ctx,
3760 struct perf_cpu_context *cpuctx)
3764 if (ctx != &cpuctx->ctx)
3767 visit_groups_merge(cpuctx, &ctx->flexible_groups,
3769 merge_sched_in, &can_add_hw);
3773 ctx_sched_in(struct perf_event_context *ctx,
3774 struct perf_cpu_context *cpuctx,
3775 enum event_type_t event_type)
3777 int is_active = ctx->is_active;
3779 lockdep_assert_held(&ctx->lock);
3781 if (likely(!ctx->nr_events))
3784 if (is_active ^ EVENT_TIME) {
3785 /* start ctx time */
3786 __update_context_time(ctx, false);
3787 perf_cgroup_set_timestamp(cpuctx);
3789 * CPU-release for the below ->is_active store,
3790 * see __load_acquire() in perf_event_time_now()
3795 ctx->is_active |= (event_type | EVENT_TIME);
3798 cpuctx->task_ctx = ctx;
3800 WARN_ON_ONCE(cpuctx->task_ctx != ctx);
3803 is_active ^= ctx->is_active; /* changed bits */
3806 * First go through the list and put on any pinned groups
3807 * in order to give them the best chance of going on.
3809 if (is_active & EVENT_PINNED)
3810 ctx_pinned_sched_in(ctx, cpuctx);
3812 /* Then walk through the lower prio flexible groups */
3813 if (is_active & EVENT_FLEXIBLE)
3814 ctx_flexible_sched_in(ctx, cpuctx);
3817 static void cpu_ctx_sched_in(struct perf_cpu_context *cpuctx,
3818 enum event_type_t event_type)
3820 struct perf_event_context *ctx = &cpuctx->ctx;
3822 ctx_sched_in(ctx, cpuctx, event_type);
3825 static void perf_event_context_sched_in(struct perf_event_context *ctx,
3826 struct task_struct *task)
3828 struct perf_cpu_context *cpuctx;
3831 cpuctx = __get_cpu_context(ctx);
3834 * HACK: for HETEROGENEOUS the task context might have switched to a
3835 * different PMU, force (re)set the context,
3837 pmu = ctx->pmu = cpuctx->ctx.pmu;
3839 if (cpuctx->task_ctx == ctx) {
3840 if (cpuctx->sched_cb_usage)
3841 __perf_pmu_sched_task(cpuctx, true);
3845 perf_ctx_lock(cpuctx, ctx);
3847 * We must check ctx->nr_events while holding ctx->lock, such
3848 * that we serialize against perf_install_in_context().
3850 if (!ctx->nr_events)
3853 perf_pmu_disable(pmu);
3855 * We want to keep the following priority order:
3856 * cpu pinned (that don't need to move), task pinned,
3857 * cpu flexible, task flexible.
3859 * However, if task's ctx is not carrying any pinned
3860 * events, no need to flip the cpuctx's events around.
3862 if (!RB_EMPTY_ROOT(&ctx->pinned_groups.tree))
3863 cpu_ctx_sched_out(cpuctx, EVENT_FLEXIBLE);
3864 perf_event_sched_in(cpuctx, ctx);
3866 if (cpuctx->sched_cb_usage && pmu->sched_task)
3867 pmu->sched_task(cpuctx->task_ctx, true);
3869 perf_pmu_enable(pmu);
3872 perf_ctx_unlock(cpuctx, ctx);
3876 * Called from scheduler to add the events of the current task
3877 * with interrupts disabled.
3879 * We restore the event value and then enable it.
3881 * This does not protect us against NMI, but enable()
3882 * sets the enabled bit in the control field of event _before_
3883 * accessing the event control register. If a NMI hits, then it will
3884 * keep the event running.
3886 void __perf_event_task_sched_in(struct task_struct *prev,
3887 struct task_struct *task)
3889 struct perf_event_context *ctx;
3892 for_each_task_context_nr(ctxn) {
3893 ctx = task->perf_event_ctxp[ctxn];
3897 perf_event_context_sched_in(ctx, task);
3900 if (atomic_read(&nr_switch_events))
3901 perf_event_switch(task, prev, true);
3903 if (__this_cpu_read(perf_sched_cb_usages))
3904 perf_pmu_sched_task(prev, task, true);
3907 static u64 perf_calculate_period(struct perf_event *event, u64 nsec, u64 count)
3909 u64 frequency = event->attr.sample_freq;
3910 u64 sec = NSEC_PER_SEC;
3911 u64 divisor, dividend;
3913 int count_fls, nsec_fls, frequency_fls, sec_fls;
3915 count_fls = fls64(count);
3916 nsec_fls = fls64(nsec);
3917 frequency_fls = fls64(frequency);
3921 * We got @count in @nsec, with a target of sample_freq HZ
3922 * the target period becomes:
3925 * period = -------------------
3926 * @nsec * sample_freq
3931 * Reduce accuracy by one bit such that @a and @b converge
3932 * to a similar magnitude.
3934 #define REDUCE_FLS(a, b) \
3936 if (a##_fls > b##_fls) { \
3946 * Reduce accuracy until either term fits in a u64, then proceed with
3947 * the other, so that finally we can do a u64/u64 division.
3949 while (count_fls + sec_fls > 64 && nsec_fls + frequency_fls > 64) {
3950 REDUCE_FLS(nsec, frequency);
3951 REDUCE_FLS(sec, count);
3954 if (count_fls + sec_fls > 64) {
3955 divisor = nsec * frequency;
3957 while (count_fls + sec_fls > 64) {
3958 REDUCE_FLS(count, sec);
3962 dividend = count * sec;
3964 dividend = count * sec;
3966 while (nsec_fls + frequency_fls > 64) {
3967 REDUCE_FLS(nsec, frequency);
3971 divisor = nsec * frequency;
3977 return div64_u64(dividend, divisor);
3980 static DEFINE_PER_CPU(int, perf_throttled_count);
3981 static DEFINE_PER_CPU(u64, perf_throttled_seq);
3983 static void perf_adjust_period(struct perf_event *event, u64 nsec, u64 count, bool disable)
3985 struct hw_perf_event *hwc = &event->hw;
3986 s64 period, sample_period;
3989 period = perf_calculate_period(event, nsec, count);
3991 delta = (s64)(period - hwc->sample_period);
3992 delta = (delta + 7) / 8; /* low pass filter */
3994 sample_period = hwc->sample_period + delta;
3999 hwc->sample_period = sample_period;
4001 if (local64_read(&hwc->period_left) > 8*sample_period) {
4003 event->pmu->stop(event, PERF_EF_UPDATE);
4005 local64_set(&hwc->period_left, 0);
4008 event->pmu->start(event, PERF_EF_RELOAD);
4013 * combine freq adjustment with unthrottling to avoid two passes over the
4014 * events. At the same time, make sure, having freq events does not change
4015 * the rate of unthrottling as that would introduce bias.
4017 static void perf_adjust_freq_unthr_context(struct perf_event_context *ctx,
4020 struct perf_event *event;
4021 struct hw_perf_event *hwc;
4022 u64 now, period = TICK_NSEC;
4026 * only need to iterate over all events iff:
4027 * - context have events in frequency mode (needs freq adjust)
4028 * - there are events to unthrottle on this cpu
4030 if (!(ctx->nr_freq || needs_unthr))
4033 raw_spin_lock(&ctx->lock);
4034 perf_pmu_disable(ctx->pmu);
4036 list_for_each_entry_rcu(event, &ctx->event_list, event_entry) {
4037 if (event->state != PERF_EVENT_STATE_ACTIVE)
4040 if (!event_filter_match(event))
4043 perf_pmu_disable(event->pmu);
4047 if (hwc->interrupts == MAX_INTERRUPTS) {
4048 hwc->interrupts = 0;
4049 perf_log_throttle(event, 1);
4050 event->pmu->start(event, 0);
4053 if (!event->attr.freq || !event->attr.sample_freq)
4057 * stop the event and update event->count
4059 event->pmu->stop(event, PERF_EF_UPDATE);
4061 now = local64_read(&event->count);
4062 delta = now - hwc->freq_count_stamp;
4063 hwc->freq_count_stamp = now;
4067 * reload only if value has changed
4068 * we have stopped the event so tell that
4069 * to perf_adjust_period() to avoid stopping it
4073 perf_adjust_period(event, period, delta, false);
4075 event->pmu->start(event, delta > 0 ? PERF_EF_RELOAD : 0);
4077 perf_pmu_enable(event->pmu);
4080 perf_pmu_enable(ctx->pmu);
4081 raw_spin_unlock(&ctx->lock);
4085 * Move @event to the tail of the @ctx's elegible events.
4087 static void rotate_ctx(struct perf_event_context *ctx, struct perf_event *event)
4090 * Rotate the first entry last of non-pinned groups. Rotation might be
4091 * disabled by the inheritance code.
4093 if (ctx->rotate_disable)
4096 perf_event_groups_delete(&ctx->flexible_groups, event);
4097 perf_event_groups_insert(&ctx->flexible_groups, event);
4100 /* pick an event from the flexible_groups to rotate */
4101 static inline struct perf_event *
4102 ctx_event_to_rotate(struct perf_event_context *ctx)
4104 struct perf_event *event;
4106 /* pick the first active flexible event */
4107 event = list_first_entry_or_null(&ctx->flexible_active,
4108 struct perf_event, active_list);
4110 /* if no active flexible event, pick the first event */
4112 event = rb_entry_safe(rb_first(&ctx->flexible_groups.tree),
4113 typeof(*event), group_node);
4117 * Unconditionally clear rotate_necessary; if ctx_flexible_sched_in()
4118 * finds there are unschedulable events, it will set it again.
4120 ctx->rotate_necessary = 0;
4125 static bool perf_rotate_context(struct perf_cpu_context *cpuctx)
4127 struct perf_event *cpu_event = NULL, *task_event = NULL;
4128 struct perf_event_context *task_ctx = NULL;
4129 int cpu_rotate, task_rotate;
4132 * Since we run this from IRQ context, nobody can install new
4133 * events, thus the event count values are stable.
4136 cpu_rotate = cpuctx->ctx.rotate_necessary;
4137 task_ctx = cpuctx->task_ctx;
4138 task_rotate = task_ctx ? task_ctx->rotate_necessary : 0;
4140 if (!(cpu_rotate || task_rotate))
4143 perf_ctx_lock(cpuctx, cpuctx->task_ctx);
4144 perf_pmu_disable(cpuctx->ctx.pmu);
4147 task_event = ctx_event_to_rotate(task_ctx);
4149 cpu_event = ctx_event_to_rotate(&cpuctx->ctx);
4152 * As per the order given at ctx_resched() first 'pop' task flexible
4153 * and then, if needed CPU flexible.
4155 if (task_event || (task_ctx && cpu_event))
4156 ctx_sched_out(task_ctx, cpuctx, EVENT_FLEXIBLE);
4158 cpu_ctx_sched_out(cpuctx, EVENT_FLEXIBLE);
4161 rotate_ctx(task_ctx, task_event);
4163 rotate_ctx(&cpuctx->ctx, cpu_event);
4165 perf_event_sched_in(cpuctx, task_ctx);
4167 perf_pmu_enable(cpuctx->ctx.pmu);
4168 perf_ctx_unlock(cpuctx, cpuctx->task_ctx);
4173 void perf_event_task_tick(void)
4175 struct list_head *head = this_cpu_ptr(&active_ctx_list);
4176 struct perf_event_context *ctx, *tmp;
4179 lockdep_assert_irqs_disabled();
4181 __this_cpu_inc(perf_throttled_seq);
4182 throttled = __this_cpu_xchg(perf_throttled_count, 0);
4183 tick_dep_clear_cpu(smp_processor_id(), TICK_DEP_BIT_PERF_EVENTS);
4185 list_for_each_entry_safe(ctx, tmp, head, active_ctx_list)
4186 perf_adjust_freq_unthr_context(ctx, throttled);
4189 static int event_enable_on_exec(struct perf_event *event,
4190 struct perf_event_context *ctx)
4192 if (!event->attr.enable_on_exec)
4195 event->attr.enable_on_exec = 0;
4196 if (event->state >= PERF_EVENT_STATE_INACTIVE)
4199 perf_event_set_state(event, PERF_EVENT_STATE_INACTIVE);
4205 * Enable all of a task's events that have been marked enable-on-exec.
4206 * This expects task == current.
4208 static void perf_event_enable_on_exec(int ctxn)
4210 struct perf_event_context *ctx, *clone_ctx = NULL;
4211 enum event_type_t event_type = 0;
4212 struct perf_cpu_context *cpuctx;
4213 struct perf_event *event;
4214 unsigned long flags;
4217 local_irq_save(flags);
4218 ctx = current->perf_event_ctxp[ctxn];
4219 if (!ctx || !ctx->nr_events)
4222 cpuctx = __get_cpu_context(ctx);
4223 perf_ctx_lock(cpuctx, ctx);
4224 ctx_sched_out(ctx, cpuctx, EVENT_TIME);
4225 list_for_each_entry(event, &ctx->event_list, event_entry) {
4226 enabled |= event_enable_on_exec(event, ctx);
4227 event_type |= get_event_type(event);
4231 * Unclone and reschedule this context if we enabled any event.
4234 clone_ctx = unclone_ctx(ctx);
4235 ctx_resched(cpuctx, ctx, event_type);
4237 ctx_sched_in(ctx, cpuctx, EVENT_TIME);
4239 perf_ctx_unlock(cpuctx, ctx);
4242 local_irq_restore(flags);
4248 static void perf_remove_from_owner(struct perf_event *event);
4249 static void perf_event_exit_event(struct perf_event *event,
4250 struct perf_event_context *ctx);
4253 * Removes all events from the current task that have been marked
4254 * remove-on-exec, and feeds their values back to parent events.
4256 static void perf_event_remove_on_exec(int ctxn)
4258 struct perf_event_context *ctx, *clone_ctx = NULL;
4259 struct perf_event *event, *next;
4260 unsigned long flags;
4261 bool modified = false;
4263 ctx = perf_pin_task_context(current, ctxn);
4267 mutex_lock(&ctx->mutex);
4269 if (WARN_ON_ONCE(ctx->task != current))
4272 list_for_each_entry_safe(event, next, &ctx->event_list, event_entry) {
4273 if (!event->attr.remove_on_exec)
4276 if (!is_kernel_event(event))
4277 perf_remove_from_owner(event);
4281 perf_event_exit_event(event, ctx);
4284 raw_spin_lock_irqsave(&ctx->lock, flags);
4286 clone_ctx = unclone_ctx(ctx);
4288 raw_spin_unlock_irqrestore(&ctx->lock, flags);
4291 mutex_unlock(&ctx->mutex);
4298 struct perf_read_data {
4299 struct perf_event *event;
4304 static int __perf_event_read_cpu(struct perf_event *event, int event_cpu)
4306 u16 local_pkg, event_pkg;
4308 if (event->group_caps & PERF_EV_CAP_READ_ACTIVE_PKG) {
4309 int local_cpu = smp_processor_id();
4311 event_pkg = topology_physical_package_id(event_cpu);
4312 local_pkg = topology_physical_package_id(local_cpu);
4314 if (event_pkg == local_pkg)
4322 * Cross CPU call to read the hardware event
4324 static void __perf_event_read(void *info)
4326 struct perf_read_data *data = info;
4327 struct perf_event *sub, *event = data->event;
4328 struct perf_event_context *ctx = event->ctx;
4329 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
4330 struct pmu *pmu = event->pmu;
4333 * If this is a task context, we need to check whether it is
4334 * the current task context of this cpu. If not it has been
4335 * scheduled out before the smp call arrived. In that case
4336 * event->count would have been updated to a recent sample
4337 * when the event was scheduled out.
4339 if (ctx->task && cpuctx->task_ctx != ctx)
4342 raw_spin_lock(&ctx->lock);
4343 if (ctx->is_active & EVENT_TIME) {
4344 update_context_time(ctx);
4345 update_cgrp_time_from_event(event);
4348 perf_event_update_time(event);
4350 perf_event_update_sibling_time(event);
4352 if (event->state != PERF_EVENT_STATE_ACTIVE)
4361 pmu->start_txn(pmu, PERF_PMU_TXN_READ);
4365 for_each_sibling_event(sub, event) {
4366 if (sub->state == PERF_EVENT_STATE_ACTIVE) {
4368 * Use sibling's PMU rather than @event's since
4369 * sibling could be on different (eg: software) PMU.
4371 sub->pmu->read(sub);
4375 data->ret = pmu->commit_txn(pmu);
4378 raw_spin_unlock(&ctx->lock);
4381 static inline u64 perf_event_count(struct perf_event *event)
4383 return local64_read(&event->count) + atomic64_read(&event->child_count);
4386 static void calc_timer_values(struct perf_event *event,
4393 *now = perf_clock();
4394 ctx_time = perf_event_time_now(event, *now);
4395 __perf_update_times(event, ctx_time, enabled, running);
4399 * NMI-safe method to read a local event, that is an event that
4401 * - either for the current task, or for this CPU
4402 * - does not have inherit set, for inherited task events
4403 * will not be local and we cannot read them atomically
4404 * - must not have a pmu::count method
4406 int perf_event_read_local(struct perf_event *event, u64 *value,
4407 u64 *enabled, u64 *running)
4409 unsigned long flags;
4413 * Disabling interrupts avoids all counter scheduling (context
4414 * switches, timer based rotation and IPIs).
4416 local_irq_save(flags);
4419 * It must not be an event with inherit set, we cannot read
4420 * all child counters from atomic context.
4422 if (event->attr.inherit) {
4427 /* If this is a per-task event, it must be for current */
4428 if ((event->attach_state & PERF_ATTACH_TASK) &&
4429 event->hw.target != current) {
4434 /* If this is a per-CPU event, it must be for this CPU */
4435 if (!(event->attach_state & PERF_ATTACH_TASK) &&
4436 event->cpu != smp_processor_id()) {
4441 /* If this is a pinned event it must be running on this CPU */
4442 if (event->attr.pinned && event->oncpu != smp_processor_id()) {
4448 * If the event is currently on this CPU, its either a per-task event,
4449 * or local to this CPU. Furthermore it means its ACTIVE (otherwise
4452 if (event->oncpu == smp_processor_id())
4453 event->pmu->read(event);
4455 *value = local64_read(&event->count);
4456 if (enabled || running) {
4457 u64 __enabled, __running, __now;;
4459 calc_timer_values(event, &__now, &__enabled, &__running);
4461 *enabled = __enabled;
4463 *running = __running;
4466 local_irq_restore(flags);
4471 static int perf_event_read(struct perf_event *event, bool group)
4473 enum perf_event_state state = READ_ONCE(event->state);
4474 int event_cpu, ret = 0;
4477 * If event is enabled and currently active on a CPU, update the
4478 * value in the event structure:
4481 if (state == PERF_EVENT_STATE_ACTIVE) {
4482 struct perf_read_data data;
4485 * Orders the ->state and ->oncpu loads such that if we see
4486 * ACTIVE we must also see the right ->oncpu.
4488 * Matches the smp_wmb() from event_sched_in().
4492 event_cpu = READ_ONCE(event->oncpu);
4493 if ((unsigned)event_cpu >= nr_cpu_ids)
4496 data = (struct perf_read_data){
4503 event_cpu = __perf_event_read_cpu(event, event_cpu);
4506 * Purposely ignore the smp_call_function_single() return
4509 * If event_cpu isn't a valid CPU it means the event got
4510 * scheduled out and that will have updated the event count.
4512 * Therefore, either way, we'll have an up-to-date event count
4515 (void)smp_call_function_single(event_cpu, __perf_event_read, &data, 1);
4519 } else if (state == PERF_EVENT_STATE_INACTIVE) {
4520 struct perf_event_context *ctx = event->ctx;
4521 unsigned long flags;
4523 raw_spin_lock_irqsave(&ctx->lock, flags);
4524 state = event->state;
4525 if (state != PERF_EVENT_STATE_INACTIVE) {
4526 raw_spin_unlock_irqrestore(&ctx->lock, flags);
4531 * May read while context is not active (e.g., thread is
4532 * blocked), in that case we cannot update context time
4534 if (ctx->is_active & EVENT_TIME) {
4535 update_context_time(ctx);
4536 update_cgrp_time_from_event(event);
4539 perf_event_update_time(event);
4541 perf_event_update_sibling_time(event);
4542 raw_spin_unlock_irqrestore(&ctx->lock, flags);
4549 * Initialize the perf_event context in a task_struct:
4551 static void __perf_event_init_context(struct perf_event_context *ctx)
4553 raw_spin_lock_init(&ctx->lock);
4554 mutex_init(&ctx->mutex);
4555 INIT_LIST_HEAD(&ctx->active_ctx_list);
4556 perf_event_groups_init(&ctx->pinned_groups);
4557 perf_event_groups_init(&ctx->flexible_groups);
4558 INIT_LIST_HEAD(&ctx->event_list);
4559 INIT_LIST_HEAD(&ctx->pinned_active);
4560 INIT_LIST_HEAD(&ctx->flexible_active);
4561 refcount_set(&ctx->refcount, 1);
4564 static struct perf_event_context *
4565 alloc_perf_context(struct pmu *pmu, struct task_struct *task)
4567 struct perf_event_context *ctx;
4569 ctx = kzalloc(sizeof(struct perf_event_context), GFP_KERNEL);
4573 __perf_event_init_context(ctx);
4575 ctx->task = get_task_struct(task);
4581 static struct task_struct *
4582 find_lively_task_by_vpid(pid_t vpid)
4584 struct task_struct *task;
4590 task = find_task_by_vpid(vpid);
4592 get_task_struct(task);
4596 return ERR_PTR(-ESRCH);
4602 * Returns a matching context with refcount and pincount.
4604 static struct perf_event_context *
4605 find_get_context(struct pmu *pmu, struct task_struct *task,
4606 struct perf_event *event)
4608 struct perf_event_context *ctx, *clone_ctx = NULL;
4609 struct perf_cpu_context *cpuctx;
4610 void *task_ctx_data = NULL;
4611 unsigned long flags;
4613 int cpu = event->cpu;
4616 /* Must be root to operate on a CPU event: */
4617 err = perf_allow_cpu(&event->attr);
4619 return ERR_PTR(err);
4621 cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
4624 raw_spin_lock_irqsave(&ctx->lock, flags);
4626 raw_spin_unlock_irqrestore(&ctx->lock, flags);
4632 ctxn = pmu->task_ctx_nr;
4636 if (event->attach_state & PERF_ATTACH_TASK_DATA) {
4637 task_ctx_data = alloc_task_ctx_data(pmu);
4638 if (!task_ctx_data) {
4645 ctx = perf_lock_task_context(task, ctxn, &flags);
4647 clone_ctx = unclone_ctx(ctx);
4650 if (task_ctx_data && !ctx->task_ctx_data) {
4651 ctx->task_ctx_data = task_ctx_data;
4652 task_ctx_data = NULL;
4654 raw_spin_unlock_irqrestore(&ctx->lock, flags);
4659 ctx = alloc_perf_context(pmu, task);
4664 if (task_ctx_data) {
4665 ctx->task_ctx_data = task_ctx_data;
4666 task_ctx_data = NULL;
4670 mutex_lock(&task->perf_event_mutex);
4672 * If it has already passed perf_event_exit_task().
4673 * we must see PF_EXITING, it takes this mutex too.
4675 if (task->flags & PF_EXITING)
4677 else if (task->perf_event_ctxp[ctxn])
4682 rcu_assign_pointer(task->perf_event_ctxp[ctxn], ctx);
4684 mutex_unlock(&task->perf_event_mutex);
4686 if (unlikely(err)) {
4695 free_task_ctx_data(pmu, task_ctx_data);
4699 free_task_ctx_data(pmu, task_ctx_data);
4700 return ERR_PTR(err);
4703 static void perf_event_free_filter(struct perf_event *event);
4705 static void free_event_rcu(struct rcu_head *head)
4707 struct perf_event *event;
4709 event = container_of(head, struct perf_event, rcu_head);
4711 put_pid_ns(event->ns);
4712 perf_event_free_filter(event);
4713 kmem_cache_free(perf_event_cache, event);
4716 static void ring_buffer_attach(struct perf_event *event,
4717 struct perf_buffer *rb);
4719 static void detach_sb_event(struct perf_event *event)
4721 struct pmu_event_list *pel = per_cpu_ptr(&pmu_sb_events, event->cpu);
4723 raw_spin_lock(&pel->lock);
4724 list_del_rcu(&event->sb_list);
4725 raw_spin_unlock(&pel->lock);
4728 static bool is_sb_event(struct perf_event *event)
4730 struct perf_event_attr *attr = &event->attr;
4735 if (event->attach_state & PERF_ATTACH_TASK)
4738 if (attr->mmap || attr->mmap_data || attr->mmap2 ||
4739 attr->comm || attr->comm_exec ||
4740 attr->task || attr->ksymbol ||
4741 attr->context_switch || attr->text_poke ||
4747 static void unaccount_pmu_sb_event(struct perf_event *event)
4749 if (is_sb_event(event))
4750 detach_sb_event(event);
4753 static void unaccount_event_cpu(struct perf_event *event, int cpu)
4758 if (is_cgroup_event(event))
4759 atomic_dec(&per_cpu(perf_cgroup_events, cpu));
4762 #ifdef CONFIG_NO_HZ_FULL
4763 static DEFINE_SPINLOCK(nr_freq_lock);
4766 static void unaccount_freq_event_nohz(void)
4768 #ifdef CONFIG_NO_HZ_FULL
4769 spin_lock(&nr_freq_lock);
4770 if (atomic_dec_and_test(&nr_freq_events))
4771 tick_nohz_dep_clear(TICK_DEP_BIT_PERF_EVENTS);
4772 spin_unlock(&nr_freq_lock);
4776 static void unaccount_freq_event(void)
4778 if (tick_nohz_full_enabled())
4779 unaccount_freq_event_nohz();
4781 atomic_dec(&nr_freq_events);
4784 static void unaccount_event(struct perf_event *event)
4791 if (event->attach_state & (PERF_ATTACH_TASK | PERF_ATTACH_SCHED_CB))
4793 if (event->attr.mmap || event->attr.mmap_data)
4794 atomic_dec(&nr_mmap_events);
4795 if (event->attr.build_id)
4796 atomic_dec(&nr_build_id_events);
4797 if (event->attr.comm)
4798 atomic_dec(&nr_comm_events);
4799 if (event->attr.namespaces)
4800 atomic_dec(&nr_namespaces_events);
4801 if (event->attr.cgroup)
4802 atomic_dec(&nr_cgroup_events);
4803 if (event->attr.task)
4804 atomic_dec(&nr_task_events);
4805 if (event->attr.freq)
4806 unaccount_freq_event();
4807 if (event->attr.context_switch) {
4809 atomic_dec(&nr_switch_events);
4811 if (is_cgroup_event(event))
4813 if (has_branch_stack(event))
4815 if (event->attr.ksymbol)
4816 atomic_dec(&nr_ksymbol_events);
4817 if (event->attr.bpf_event)
4818 atomic_dec(&nr_bpf_events);
4819 if (event->attr.text_poke)
4820 atomic_dec(&nr_text_poke_events);
4823 if (!atomic_add_unless(&perf_sched_count, -1, 1))
4824 schedule_delayed_work(&perf_sched_work, HZ);
4827 unaccount_event_cpu(event, event->cpu);
4829 unaccount_pmu_sb_event(event);
4832 static void perf_sched_delayed(struct work_struct *work)
4834 mutex_lock(&perf_sched_mutex);
4835 if (atomic_dec_and_test(&perf_sched_count))
4836 static_branch_disable(&perf_sched_events);
4837 mutex_unlock(&perf_sched_mutex);
4841 * The following implement mutual exclusion of events on "exclusive" pmus
4842 * (PERF_PMU_CAP_EXCLUSIVE). Such pmus can only have one event scheduled
4843 * at a time, so we disallow creating events that might conflict, namely:
4845 * 1) cpu-wide events in the presence of per-task events,
4846 * 2) per-task events in the presence of cpu-wide events,
4847 * 3) two matching events on the same context.
4849 * The former two cases are handled in the allocation path (perf_event_alloc(),
4850 * _free_event()), the latter -- before the first perf_install_in_context().
4852 static int exclusive_event_init(struct perf_event *event)
4854 struct pmu *pmu = event->pmu;
4856 if (!is_exclusive_pmu(pmu))
4860 * Prevent co-existence of per-task and cpu-wide events on the
4861 * same exclusive pmu.
4863 * Negative pmu::exclusive_cnt means there are cpu-wide
4864 * events on this "exclusive" pmu, positive means there are
4867 * Since this is called in perf_event_alloc() path, event::ctx
4868 * doesn't exist yet; it is, however, safe to use PERF_ATTACH_TASK
4869 * to mean "per-task event", because unlike other attach states it
4870 * never gets cleared.
4872 if (event->attach_state & PERF_ATTACH_TASK) {
4873 if (!atomic_inc_unless_negative(&pmu->exclusive_cnt))
4876 if (!atomic_dec_unless_positive(&pmu->exclusive_cnt))
4883 static void exclusive_event_destroy(struct perf_event *event)
4885 struct pmu *pmu = event->pmu;
4887 if (!is_exclusive_pmu(pmu))
4890 /* see comment in exclusive_event_init() */
4891 if (event->attach_state & PERF_ATTACH_TASK)
4892 atomic_dec(&pmu->exclusive_cnt);
4894 atomic_inc(&pmu->exclusive_cnt);
4897 static bool exclusive_event_match(struct perf_event *e1, struct perf_event *e2)
4899 if ((e1->pmu == e2->pmu) &&
4900 (e1->cpu == e2->cpu ||
4907 static bool exclusive_event_installable(struct perf_event *event,
4908 struct perf_event_context *ctx)
4910 struct perf_event *iter_event;
4911 struct pmu *pmu = event->pmu;
4913 lockdep_assert_held(&ctx->mutex);
4915 if (!is_exclusive_pmu(pmu))
4918 list_for_each_entry(iter_event, &ctx->event_list, event_entry) {
4919 if (exclusive_event_match(iter_event, event))
4926 static void perf_addr_filters_splice(struct perf_event *event,
4927 struct list_head *head);
4929 static void _free_event(struct perf_event *event)
4931 irq_work_sync(&event->pending);
4933 unaccount_event(event);
4935 security_perf_event_free(event);
4939 * Can happen when we close an event with re-directed output.
4941 * Since we have a 0 refcount, perf_mmap_close() will skip
4942 * over us; possibly making our ring_buffer_put() the last.
4944 mutex_lock(&event->mmap_mutex);
4945 ring_buffer_attach(event, NULL);
4946 mutex_unlock(&event->mmap_mutex);
4949 if (is_cgroup_event(event))
4950 perf_detach_cgroup(event);
4952 if (!event->parent) {
4953 if (event->attr.sample_type & PERF_SAMPLE_CALLCHAIN)
4954 put_callchain_buffers();
4957 perf_event_free_bpf_prog(event);
4958 perf_addr_filters_splice(event, NULL);
4959 kfree(event->addr_filter_ranges);
4962 event->destroy(event);
4965 * Must be after ->destroy(), due to uprobe_perf_close() using
4968 if (event->hw.target)
4969 put_task_struct(event->hw.target);
4972 * perf_event_free_task() relies on put_ctx() being 'last', in particular
4973 * all task references must be cleaned up.
4976 put_ctx(event->ctx);
4978 exclusive_event_destroy(event);
4979 module_put(event->pmu->module);
4981 call_rcu(&event->rcu_head, free_event_rcu);
4985 * Used to free events which have a known refcount of 1, such as in error paths
4986 * where the event isn't exposed yet and inherited events.
4988 static void free_event(struct perf_event *event)
4990 if (WARN(atomic_long_cmpxchg(&event->refcount, 1, 0) != 1,
4991 "unexpected event refcount: %ld; ptr=%p\n",
4992 atomic_long_read(&event->refcount), event)) {
4993 /* leak to avoid use-after-free */
5001 * Remove user event from the owner task.
5003 static void perf_remove_from_owner(struct perf_event *event)
5005 struct task_struct *owner;
5009 * Matches the smp_store_release() in perf_event_exit_task(). If we
5010 * observe !owner it means the list deletion is complete and we can
5011 * indeed free this event, otherwise we need to serialize on
5012 * owner->perf_event_mutex.
5014 owner = READ_ONCE(event->owner);
5017 * Since delayed_put_task_struct() also drops the last
5018 * task reference we can safely take a new reference
5019 * while holding the rcu_read_lock().
5021 get_task_struct(owner);
5027 * If we're here through perf_event_exit_task() we're already
5028 * holding ctx->mutex which would be an inversion wrt. the
5029 * normal lock order.
5031 * However we can safely take this lock because its the child
5034 mutex_lock_nested(&owner->perf_event_mutex, SINGLE_DEPTH_NESTING);
5037 * We have to re-check the event->owner field, if it is cleared
5038 * we raced with perf_event_exit_task(), acquiring the mutex
5039 * ensured they're done, and we can proceed with freeing the
5043 list_del_init(&event->owner_entry);
5044 smp_store_release(&event->owner, NULL);
5046 mutex_unlock(&owner->perf_event_mutex);
5047 put_task_struct(owner);
5051 static void put_event(struct perf_event *event)
5053 if (!atomic_long_dec_and_test(&event->refcount))
5060 * Kill an event dead; while event:refcount will preserve the event
5061 * object, it will not preserve its functionality. Once the last 'user'
5062 * gives up the object, we'll destroy the thing.
5064 int perf_event_release_kernel(struct perf_event *event)
5066 struct perf_event_context *ctx = event->ctx;
5067 struct perf_event *child, *tmp;
5068 LIST_HEAD(free_list);
5071 * If we got here through err_file: fput(event_file); we will not have
5072 * attached to a context yet.
5075 WARN_ON_ONCE(event->attach_state &
5076 (PERF_ATTACH_CONTEXT|PERF_ATTACH_GROUP));
5080 if (!is_kernel_event(event))
5081 perf_remove_from_owner(event);
5083 ctx = perf_event_ctx_lock(event);
5084 WARN_ON_ONCE(ctx->parent_ctx);
5085 perf_remove_from_context(event, DETACH_GROUP);
5087 raw_spin_lock_irq(&ctx->lock);
5089 * Mark this event as STATE_DEAD, there is no external reference to it
5092 * Anybody acquiring event->child_mutex after the below loop _must_
5093 * also see this, most importantly inherit_event() which will avoid
5094 * placing more children on the list.
5096 * Thus this guarantees that we will in fact observe and kill _ALL_
5099 event->state = PERF_EVENT_STATE_DEAD;
5100 raw_spin_unlock_irq(&ctx->lock);
5102 perf_event_ctx_unlock(event, ctx);
5105 mutex_lock(&event->child_mutex);
5106 list_for_each_entry(child, &event->child_list, child_list) {
5109 * Cannot change, child events are not migrated, see the
5110 * comment with perf_event_ctx_lock_nested().
5112 ctx = READ_ONCE(child->ctx);
5114 * Since child_mutex nests inside ctx::mutex, we must jump
5115 * through hoops. We start by grabbing a reference on the ctx.
5117 * Since the event cannot get freed while we hold the
5118 * child_mutex, the context must also exist and have a !0
5124 * Now that we have a ctx ref, we can drop child_mutex, and
5125 * acquire ctx::mutex without fear of it going away. Then we
5126 * can re-acquire child_mutex.
5128 mutex_unlock(&event->child_mutex);
5129 mutex_lock(&ctx->mutex);
5130 mutex_lock(&event->child_mutex);
5133 * Now that we hold ctx::mutex and child_mutex, revalidate our
5134 * state, if child is still the first entry, it didn't get freed
5135 * and we can continue doing so.
5137 tmp = list_first_entry_or_null(&event->child_list,
5138 struct perf_event, child_list);
5140 perf_remove_from_context(child, DETACH_GROUP);
5141 list_move(&child->child_list, &free_list);
5143 * This matches the refcount bump in inherit_event();
5144 * this can't be the last reference.
5149 mutex_unlock(&event->child_mutex);
5150 mutex_unlock(&ctx->mutex);
5154 mutex_unlock(&event->child_mutex);
5156 list_for_each_entry_safe(child, tmp, &free_list, child_list) {
5157 void *var = &child->ctx->refcount;
5159 list_del(&child->child_list);
5163 * Wake any perf_event_free_task() waiting for this event to be
5166 smp_mb(); /* pairs with wait_var_event() */
5171 put_event(event); /* Must be the 'last' reference */
5174 EXPORT_SYMBOL_GPL(perf_event_release_kernel);
5177 * Called when the last reference to the file is gone.
5179 static int perf_release(struct inode *inode, struct file *file)
5181 perf_event_release_kernel(file->private_data);
5185 static u64 __perf_event_read_value(struct perf_event *event, u64 *enabled, u64 *running)
5187 struct perf_event *child;
5193 mutex_lock(&event->child_mutex);
5195 (void)perf_event_read(event, false);
5196 total += perf_event_count(event);
5198 *enabled += event->total_time_enabled +
5199 atomic64_read(&event->child_total_time_enabled);
5200 *running += event->total_time_running +
5201 atomic64_read(&event->child_total_time_running);
5203 list_for_each_entry(child, &event->child_list, child_list) {
5204 (void)perf_event_read(child, false);
5205 total += perf_event_count(child);
5206 *enabled += child->total_time_enabled;
5207 *running += child->total_time_running;
5209 mutex_unlock(&event->child_mutex);
5214 u64 perf_event_read_value(struct perf_event *event, u64 *enabled, u64 *running)
5216 struct perf_event_context *ctx;
5219 ctx = perf_event_ctx_lock(event);
5220 count = __perf_event_read_value(event, enabled, running);
5221 perf_event_ctx_unlock(event, ctx);
5225 EXPORT_SYMBOL_GPL(perf_event_read_value);
5227 static int __perf_read_group_add(struct perf_event *leader,
5228 u64 read_format, u64 *values)
5230 struct perf_event_context *ctx = leader->ctx;
5231 struct perf_event *sub;
5232 unsigned long flags;
5233 int n = 1; /* skip @nr */
5236 ret = perf_event_read(leader, true);
5240 raw_spin_lock_irqsave(&ctx->lock, flags);
5243 * Since we co-schedule groups, {enabled,running} times of siblings
5244 * will be identical to those of the leader, so we only publish one
5247 if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED) {
5248 values[n++] += leader->total_time_enabled +
5249 atomic64_read(&leader->child_total_time_enabled);
5252 if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING) {
5253 values[n++] += leader->total_time_running +
5254 atomic64_read(&leader->child_total_time_running);
5258 * Write {count,id} tuples for every sibling.
5260 values[n++] += perf_event_count(leader);
5261 if (read_format & PERF_FORMAT_ID)
5262 values[n++] = primary_event_id(leader);
5264 for_each_sibling_event(sub, leader) {
5265 values[n++] += perf_event_count(sub);
5266 if (read_format & PERF_FORMAT_ID)
5267 values[n++] = primary_event_id(sub);
5270 raw_spin_unlock_irqrestore(&ctx->lock, flags);
5274 static int perf_read_group(struct perf_event *event,
5275 u64 read_format, char __user *buf)
5277 struct perf_event *leader = event->group_leader, *child;
5278 struct perf_event_context *ctx = leader->ctx;
5282 lockdep_assert_held(&ctx->mutex);
5284 values = kzalloc(event->read_size, GFP_KERNEL);
5288 values[0] = 1 + leader->nr_siblings;
5291 * By locking the child_mutex of the leader we effectively
5292 * lock the child list of all siblings.. XXX explain how.
5294 mutex_lock(&leader->child_mutex);
5296 ret = __perf_read_group_add(leader, read_format, values);
5300 list_for_each_entry(child, &leader->child_list, child_list) {
5301 ret = __perf_read_group_add(child, read_format, values);
5306 mutex_unlock(&leader->child_mutex);
5308 ret = event->read_size;
5309 if (copy_to_user(buf, values, event->read_size))
5314 mutex_unlock(&leader->child_mutex);
5320 static int perf_read_one(struct perf_event *event,
5321 u64 read_format, char __user *buf)
5323 u64 enabled, running;
5327 values[n++] = __perf_event_read_value(event, &enabled, &running);
5328 if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED)
5329 values[n++] = enabled;
5330 if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING)
5331 values[n++] = running;
5332 if (read_format & PERF_FORMAT_ID)
5333 values[n++] = primary_event_id(event);
5335 if (copy_to_user(buf, values, n * sizeof(u64)))
5338 return n * sizeof(u64);
5341 static bool is_event_hup(struct perf_event *event)
5345 if (event->state > PERF_EVENT_STATE_EXIT)
5348 mutex_lock(&event->child_mutex);
5349 no_children = list_empty(&event->child_list);
5350 mutex_unlock(&event->child_mutex);
5355 * Read the performance event - simple non blocking version for now
5358 __perf_read(struct perf_event *event, char __user *buf, size_t count)
5360 u64 read_format = event->attr.read_format;
5364 * Return end-of-file for a read on an event that is in
5365 * error state (i.e. because it was pinned but it couldn't be
5366 * scheduled on to the CPU at some point).
5368 if (event->state == PERF_EVENT_STATE_ERROR)
5371 if (count < event->read_size)
5374 WARN_ON_ONCE(event->ctx->parent_ctx);
5375 if (read_format & PERF_FORMAT_GROUP)
5376 ret = perf_read_group(event, read_format, buf);
5378 ret = perf_read_one(event, read_format, buf);
5384 perf_read(struct file *file, char __user *buf, size_t count, loff_t *ppos)
5386 struct perf_event *event = file->private_data;
5387 struct perf_event_context *ctx;
5390 ret = security_perf_event_read(event);
5394 ctx = perf_event_ctx_lock(event);
5395 ret = __perf_read(event, buf, count);
5396 perf_event_ctx_unlock(event, ctx);
5401 static __poll_t perf_poll(struct file *file, poll_table *wait)
5403 struct perf_event *event = file->private_data;
5404 struct perf_buffer *rb;
5405 __poll_t events = EPOLLHUP;
5407 poll_wait(file, &event->waitq, wait);
5409 if (is_event_hup(event))
5413 * Pin the event->rb by taking event->mmap_mutex; otherwise
5414 * perf_event_set_output() can swizzle our rb and make us miss wakeups.
5416 mutex_lock(&event->mmap_mutex);
5419 events = atomic_xchg(&rb->poll, 0);
5420 mutex_unlock(&event->mmap_mutex);
5424 static void _perf_event_reset(struct perf_event *event)
5426 (void)perf_event_read(event, false);
5427 local64_set(&event->count, 0);
5428 perf_event_update_userpage(event);
5431 /* Assume it's not an event with inherit set. */
5432 u64 perf_event_pause(struct perf_event *event, bool reset)
5434 struct perf_event_context *ctx;
5437 ctx = perf_event_ctx_lock(event);
5438 WARN_ON_ONCE(event->attr.inherit);
5439 _perf_event_disable(event);
5440 count = local64_read(&event->count);
5442 local64_set(&event->count, 0);
5443 perf_event_ctx_unlock(event, ctx);
5447 EXPORT_SYMBOL_GPL(perf_event_pause);
5450 * Holding the top-level event's child_mutex means that any
5451 * descendant process that has inherited this event will block
5452 * in perf_event_exit_event() if it goes to exit, thus satisfying the
5453 * task existence requirements of perf_event_enable/disable.
5455 static void perf_event_for_each_child(struct perf_event *event,
5456 void (*func)(struct perf_event *))
5458 struct perf_event *child;
5460 WARN_ON_ONCE(event->ctx->parent_ctx);
5462 mutex_lock(&event->child_mutex);
5464 list_for_each_entry(child, &event->child_list, child_list)
5466 mutex_unlock(&event->child_mutex);
5469 static void perf_event_for_each(struct perf_event *event,
5470 void (*func)(struct perf_event *))
5472 struct perf_event_context *ctx = event->ctx;
5473 struct perf_event *sibling;
5475 lockdep_assert_held(&ctx->mutex);
5477 event = event->group_leader;
5479 perf_event_for_each_child(event, func);
5480 for_each_sibling_event(sibling, event)
5481 perf_event_for_each_child(sibling, func);
5484 static void __perf_event_period(struct perf_event *event,
5485 struct perf_cpu_context *cpuctx,
5486 struct perf_event_context *ctx,
5489 u64 value = *((u64 *)info);
5492 if (event->attr.freq) {
5493 event->attr.sample_freq = value;
5495 event->attr.sample_period = value;
5496 event->hw.sample_period = value;
5499 active = (event->state == PERF_EVENT_STATE_ACTIVE);
5501 perf_pmu_disable(ctx->pmu);
5503 * We could be throttled; unthrottle now to avoid the tick
5504 * trying to unthrottle while we already re-started the event.
5506 if (event->hw.interrupts == MAX_INTERRUPTS) {
5507 event->hw.interrupts = 0;
5508 perf_log_throttle(event, 1);
5510 event->pmu->stop(event, PERF_EF_UPDATE);
5513 local64_set(&event->hw.period_left, 0);
5516 event->pmu->start(event, PERF_EF_RELOAD);
5517 perf_pmu_enable(ctx->pmu);
5521 static int perf_event_check_period(struct perf_event *event, u64 value)
5523 return event->pmu->check_period(event, value);
5526 static int _perf_event_period(struct perf_event *event, u64 value)
5528 if (!is_sampling_event(event))
5534 if (event->attr.freq && value > sysctl_perf_event_sample_rate)
5537 if (perf_event_check_period(event, value))
5540 if (!event->attr.freq && (value & (1ULL << 63)))
5543 event_function_call(event, __perf_event_period, &value);
5548 int perf_event_period(struct perf_event *event, u64 value)
5550 struct perf_event_context *ctx;
5553 ctx = perf_event_ctx_lock(event);
5554 ret = _perf_event_period(event, value);
5555 perf_event_ctx_unlock(event, ctx);
5559 EXPORT_SYMBOL_GPL(perf_event_period);
5561 static const struct file_operations perf_fops;
5563 static inline int perf_fget_light(int fd, struct fd *p)
5565 struct fd f = fdget(fd);
5569 if (f.file->f_op != &perf_fops) {
5577 static int perf_event_set_output(struct perf_event *event,
5578 struct perf_event *output_event);
5579 static int perf_event_set_filter(struct perf_event *event, void __user *arg);
5580 static int perf_copy_attr(struct perf_event_attr __user *uattr,
5581 struct perf_event_attr *attr);
5583 static long _perf_ioctl(struct perf_event *event, unsigned int cmd, unsigned long arg)
5585 void (*func)(struct perf_event *);
5589 case PERF_EVENT_IOC_ENABLE:
5590 func = _perf_event_enable;
5592 case PERF_EVENT_IOC_DISABLE:
5593 func = _perf_event_disable;
5595 case PERF_EVENT_IOC_RESET:
5596 func = _perf_event_reset;
5599 case PERF_EVENT_IOC_REFRESH:
5600 return _perf_event_refresh(event, arg);
5602 case PERF_EVENT_IOC_PERIOD:
5606 if (copy_from_user(&value, (u64 __user *)arg, sizeof(value)))
5609 return _perf_event_period(event, value);
5611 case PERF_EVENT_IOC_ID:
5613 u64 id = primary_event_id(event);
5615 if (copy_to_user((void __user *)arg, &id, sizeof(id)))
5620 case PERF_EVENT_IOC_SET_OUTPUT:
5624 struct perf_event *output_event;
5626 ret = perf_fget_light(arg, &output);
5629 output_event = output.file->private_data;
5630 ret = perf_event_set_output(event, output_event);
5633 ret = perf_event_set_output(event, NULL);
5638 case PERF_EVENT_IOC_SET_FILTER:
5639 return perf_event_set_filter(event, (void __user *)arg);
5641 case PERF_EVENT_IOC_SET_BPF:
5643 struct bpf_prog *prog;
5646 prog = bpf_prog_get(arg);
5648 return PTR_ERR(prog);
5650 err = perf_event_set_bpf_prog(event, prog, 0);
5659 case PERF_EVENT_IOC_PAUSE_OUTPUT: {
5660 struct perf_buffer *rb;
5663 rb = rcu_dereference(event->rb);
5664 if (!rb || !rb->nr_pages) {
5668 rb_toggle_paused(rb, !!arg);
5673 case PERF_EVENT_IOC_QUERY_BPF:
5674 return perf_event_query_prog_array(event, (void __user *)arg);
5676 case PERF_EVENT_IOC_MODIFY_ATTRIBUTES: {
5677 struct perf_event_attr new_attr;
5678 int err = perf_copy_attr((struct perf_event_attr __user *)arg,
5684 return perf_event_modify_attr(event, &new_attr);
5690 if (flags & PERF_IOC_FLAG_GROUP)
5691 perf_event_for_each(event, func);
5693 perf_event_for_each_child(event, func);
5698 static long perf_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
5700 struct perf_event *event = file->private_data;
5701 struct perf_event_context *ctx;
5704 /* Treat ioctl like writes as it is likely a mutating operation. */
5705 ret = security_perf_event_write(event);
5709 ctx = perf_event_ctx_lock(event);
5710 ret = _perf_ioctl(event, cmd, arg);
5711 perf_event_ctx_unlock(event, ctx);
5716 #ifdef CONFIG_COMPAT
5717 static long perf_compat_ioctl(struct file *file, unsigned int cmd,
5720 switch (_IOC_NR(cmd)) {
5721 case _IOC_NR(PERF_EVENT_IOC_SET_FILTER):
5722 case _IOC_NR(PERF_EVENT_IOC_ID):
5723 case _IOC_NR(PERF_EVENT_IOC_QUERY_BPF):
5724 case _IOC_NR(PERF_EVENT_IOC_MODIFY_ATTRIBUTES):
5725 /* Fix up pointer size (usually 4 -> 8 in 32-on-64-bit case */
5726 if (_IOC_SIZE(cmd) == sizeof(compat_uptr_t)) {
5727 cmd &= ~IOCSIZE_MASK;
5728 cmd |= sizeof(void *) << IOCSIZE_SHIFT;
5732 return perf_ioctl(file, cmd, arg);
5735 # define perf_compat_ioctl NULL
5738 int perf_event_task_enable(void)
5740 struct perf_event_context *ctx;
5741 struct perf_event *event;
5743 mutex_lock(¤t->perf_event_mutex);
5744 list_for_each_entry(event, ¤t->perf_event_list, owner_entry) {
5745 ctx = perf_event_ctx_lock(event);
5746 perf_event_for_each_child(event, _perf_event_enable);
5747 perf_event_ctx_unlock(event, ctx);
5749 mutex_unlock(¤t->perf_event_mutex);
5754 int perf_event_task_disable(void)
5756 struct perf_event_context *ctx;
5757 struct perf_event *event;
5759 mutex_lock(¤t->perf_event_mutex);
5760 list_for_each_entry(event, ¤t->perf_event_list, owner_entry) {
5761 ctx = perf_event_ctx_lock(event);
5762 perf_event_for_each_child(event, _perf_event_disable);
5763 perf_event_ctx_unlock(event, ctx);
5765 mutex_unlock(¤t->perf_event_mutex);
5770 static int perf_event_index(struct perf_event *event)
5772 if (event->hw.state & PERF_HES_STOPPED)
5775 if (event->state != PERF_EVENT_STATE_ACTIVE)
5778 return event->pmu->event_idx(event);
5781 static void perf_event_init_userpage(struct perf_event *event)
5783 struct perf_event_mmap_page *userpg;
5784 struct perf_buffer *rb;
5787 rb = rcu_dereference(event->rb);
5791 userpg = rb->user_page;
5793 /* Allow new userspace to detect that bit 0 is deprecated */
5794 userpg->cap_bit0_is_deprecated = 1;
5795 userpg->size = offsetof(struct perf_event_mmap_page, __reserved);
5796 userpg->data_offset = PAGE_SIZE;
5797 userpg->data_size = perf_data_size(rb);
5803 void __weak arch_perf_update_userpage(
5804 struct perf_event *event, struct perf_event_mmap_page *userpg, u64 now)
5809 * Callers need to ensure there can be no nesting of this function, otherwise
5810 * the seqlock logic goes bad. We can not serialize this because the arch
5811 * code calls this from NMI context.
5813 void perf_event_update_userpage(struct perf_event *event)
5815 struct perf_event_mmap_page *userpg;
5816 struct perf_buffer *rb;
5817 u64 enabled, running, now;
5820 rb = rcu_dereference(event->rb);
5825 * compute total_time_enabled, total_time_running
5826 * based on snapshot values taken when the event
5827 * was last scheduled in.
5829 * we cannot simply called update_context_time()
5830 * because of locking issue as we can be called in
5833 calc_timer_values(event, &now, &enabled, &running);
5835 userpg = rb->user_page;
5837 * Disable preemption to guarantee consistent time stamps are stored to
5843 userpg->index = perf_event_index(event);
5844 userpg->offset = perf_event_count(event);
5846 userpg->offset -= local64_read(&event->hw.prev_count);
5848 userpg->time_enabled = enabled +
5849 atomic64_read(&event->child_total_time_enabled);
5851 userpg->time_running = running +
5852 atomic64_read(&event->child_total_time_running);
5854 arch_perf_update_userpage(event, userpg, now);
5862 EXPORT_SYMBOL_GPL(perf_event_update_userpage);
5864 static vm_fault_t perf_mmap_fault(struct vm_fault *vmf)
5866 struct perf_event *event = vmf->vma->vm_file->private_data;
5867 struct perf_buffer *rb;
5868 vm_fault_t ret = VM_FAULT_SIGBUS;
5870 if (vmf->flags & FAULT_FLAG_MKWRITE) {
5871 if (vmf->pgoff == 0)
5877 rb = rcu_dereference(event->rb);
5881 if (vmf->pgoff && (vmf->flags & FAULT_FLAG_WRITE))
5884 vmf->page = perf_mmap_to_page(rb, vmf->pgoff);
5888 get_page(vmf->page);
5889 vmf->page->mapping = vmf->vma->vm_file->f_mapping;
5890 vmf->page->index = vmf->pgoff;
5899 static void ring_buffer_attach(struct perf_event *event,
5900 struct perf_buffer *rb)
5902 struct perf_buffer *old_rb = NULL;
5903 unsigned long flags;
5905 WARN_ON_ONCE(event->parent);
5909 * Should be impossible, we set this when removing
5910 * event->rb_entry and wait/clear when adding event->rb_entry.
5912 WARN_ON_ONCE(event->rcu_pending);
5915 spin_lock_irqsave(&old_rb->event_lock, flags);
5916 list_del_rcu(&event->rb_entry);
5917 spin_unlock_irqrestore(&old_rb->event_lock, flags);
5919 event->rcu_batches = get_state_synchronize_rcu();
5920 event->rcu_pending = 1;
5924 if (event->rcu_pending) {
5925 cond_synchronize_rcu(event->rcu_batches);
5926 event->rcu_pending = 0;
5929 spin_lock_irqsave(&rb->event_lock, flags);
5930 list_add_rcu(&event->rb_entry, &rb->event_list);
5931 spin_unlock_irqrestore(&rb->event_lock, flags);
5935 * Avoid racing with perf_mmap_close(AUX): stop the event
5936 * before swizzling the event::rb pointer; if it's getting
5937 * unmapped, its aux_mmap_count will be 0 and it won't
5938 * restart. See the comment in __perf_pmu_output_stop().
5940 * Data will inevitably be lost when set_output is done in
5941 * mid-air, but then again, whoever does it like this is
5942 * not in for the data anyway.
5945 perf_event_stop(event, 0);
5947 rcu_assign_pointer(event->rb, rb);
5950 ring_buffer_put(old_rb);
5952 * Since we detached before setting the new rb, so that we
5953 * could attach the new rb, we could have missed a wakeup.
5956 wake_up_all(&event->waitq);
5960 static void ring_buffer_wakeup(struct perf_event *event)
5962 struct perf_buffer *rb;
5965 event = event->parent;
5968 rb = rcu_dereference(event->rb);
5970 list_for_each_entry_rcu(event, &rb->event_list, rb_entry)
5971 wake_up_all(&event->waitq);
5976 struct perf_buffer *ring_buffer_get(struct perf_event *event)
5978 struct perf_buffer *rb;
5981 event = event->parent;
5984 rb = rcu_dereference(event->rb);
5986 if (!refcount_inc_not_zero(&rb->refcount))
5994 void ring_buffer_put(struct perf_buffer *rb)
5996 if (!refcount_dec_and_test(&rb->refcount))
5999 WARN_ON_ONCE(!list_empty(&rb->event_list));
6001 call_rcu(&rb->rcu_head, rb_free_rcu);
6004 static void perf_mmap_open(struct vm_area_struct *vma)
6006 struct perf_event *event = vma->vm_file->private_data;
6008 atomic_inc(&event->mmap_count);
6009 atomic_inc(&event->rb->mmap_count);
6012 atomic_inc(&event->rb->aux_mmap_count);
6014 if (event->pmu->event_mapped)
6015 event->pmu->event_mapped(event, vma->vm_mm);
6018 static void perf_pmu_output_stop(struct perf_event *event);
6021 * A buffer can be mmap()ed multiple times; either directly through the same
6022 * event, or through other events by use of perf_event_set_output().
6024 * In order to undo the VM accounting done by perf_mmap() we need to destroy
6025 * the buffer here, where we still have a VM context. This means we need
6026 * to detach all events redirecting to us.
6028 static void perf_mmap_close(struct vm_area_struct *vma)
6030 struct perf_event *event = vma->vm_file->private_data;
6031 struct perf_buffer *rb = ring_buffer_get(event);
6032 struct user_struct *mmap_user = rb->mmap_user;
6033 int mmap_locked = rb->mmap_locked;
6034 unsigned long size = perf_data_size(rb);
6035 bool detach_rest = false;
6037 if (event->pmu->event_unmapped)
6038 event->pmu->event_unmapped(event, vma->vm_mm);
6041 * rb->aux_mmap_count will always drop before rb->mmap_count and
6042 * event->mmap_count, so it is ok to use event->mmap_mutex to
6043 * serialize with perf_mmap here.
6045 if (rb_has_aux(rb) && vma->vm_pgoff == rb->aux_pgoff &&
6046 atomic_dec_and_mutex_lock(&rb->aux_mmap_count, &event->mmap_mutex)) {
6048 * Stop all AUX events that are writing to this buffer,
6049 * so that we can free its AUX pages and corresponding PMU
6050 * data. Note that after rb::aux_mmap_count dropped to zero,
6051 * they won't start any more (see perf_aux_output_begin()).
6053 perf_pmu_output_stop(event);
6055 /* now it's safe to free the pages */
6056 atomic_long_sub(rb->aux_nr_pages - rb->aux_mmap_locked, &mmap_user->locked_vm);
6057 atomic64_sub(rb->aux_mmap_locked, &vma->vm_mm->pinned_vm);
6059 /* this has to be the last one */
6061 WARN_ON_ONCE(refcount_read(&rb->aux_refcount));
6063 mutex_unlock(&event->mmap_mutex);
6066 if (atomic_dec_and_test(&rb->mmap_count))
6069 if (!atomic_dec_and_mutex_lock(&event->mmap_count, &event->mmap_mutex))
6072 ring_buffer_attach(event, NULL);
6073 mutex_unlock(&event->mmap_mutex);
6075 /* If there's still other mmap()s of this buffer, we're done. */
6080 * No other mmap()s, detach from all other events that might redirect
6081 * into the now unreachable buffer. Somewhat complicated by the
6082 * fact that rb::event_lock otherwise nests inside mmap_mutex.
6086 list_for_each_entry_rcu(event, &rb->event_list, rb_entry) {
6087 if (!atomic_long_inc_not_zero(&event->refcount)) {
6089 * This event is en-route to free_event() which will
6090 * detach it and remove it from the list.
6096 mutex_lock(&event->mmap_mutex);
6098 * Check we didn't race with perf_event_set_output() which can
6099 * swizzle the rb from under us while we were waiting to
6100 * acquire mmap_mutex.
6102 * If we find a different rb; ignore this event, a next
6103 * iteration will no longer find it on the list. We have to
6104 * still restart the iteration to make sure we're not now
6105 * iterating the wrong list.
6107 if (event->rb == rb)
6108 ring_buffer_attach(event, NULL);
6110 mutex_unlock(&event->mmap_mutex);
6114 * Restart the iteration; either we're on the wrong list or
6115 * destroyed its integrity by doing a deletion.
6122 * It could be there's still a few 0-ref events on the list; they'll
6123 * get cleaned up by free_event() -- they'll also still have their
6124 * ref on the rb and will free it whenever they are done with it.
6126 * Aside from that, this buffer is 'fully' detached and unmapped,
6127 * undo the VM accounting.
6130 atomic_long_sub((size >> PAGE_SHIFT) + 1 - mmap_locked,
6131 &mmap_user->locked_vm);
6132 atomic64_sub(mmap_locked, &vma->vm_mm->pinned_vm);
6133 free_uid(mmap_user);
6136 ring_buffer_put(rb); /* could be last */
6139 static const struct vm_operations_struct perf_mmap_vmops = {
6140 .open = perf_mmap_open,
6141 .close = perf_mmap_close, /* non mergeable */
6142 .fault = perf_mmap_fault,
6143 .page_mkwrite = perf_mmap_fault,
6146 static int perf_mmap(struct file *file, struct vm_area_struct *vma)
6148 struct perf_event *event = file->private_data;
6149 unsigned long user_locked, user_lock_limit;
6150 struct user_struct *user = current_user();
6151 struct perf_buffer *rb = NULL;
6152 unsigned long locked, lock_limit;
6153 unsigned long vma_size;
6154 unsigned long nr_pages;
6155 long user_extra = 0, extra = 0;
6156 int ret = 0, flags = 0;
6159 * Don't allow mmap() of inherited per-task counters. This would
6160 * create a performance issue due to all children writing to the
6163 if (event->cpu == -1 && event->attr.inherit)
6166 if (!(vma->vm_flags & VM_SHARED))
6169 ret = security_perf_event_read(event);
6173 vma_size = vma->vm_end - vma->vm_start;
6175 if (vma->vm_pgoff == 0) {
6176 nr_pages = (vma_size / PAGE_SIZE) - 1;
6179 * AUX area mapping: if rb->aux_nr_pages != 0, it's already
6180 * mapped, all subsequent mappings should have the same size
6181 * and offset. Must be above the normal perf buffer.
6183 u64 aux_offset, aux_size;
6188 nr_pages = vma_size / PAGE_SIZE;
6190 mutex_lock(&event->mmap_mutex);
6197 aux_offset = READ_ONCE(rb->user_page->aux_offset);
6198 aux_size = READ_ONCE(rb->user_page->aux_size);
6200 if (aux_offset < perf_data_size(rb) + PAGE_SIZE)
6203 if (aux_offset != vma->vm_pgoff << PAGE_SHIFT)
6206 /* already mapped with a different offset */
6207 if (rb_has_aux(rb) && rb->aux_pgoff != vma->vm_pgoff)
6210 if (aux_size != vma_size || aux_size != nr_pages * PAGE_SIZE)
6213 /* already mapped with a different size */
6214 if (rb_has_aux(rb) && rb->aux_nr_pages != nr_pages)
6217 if (!is_power_of_2(nr_pages))
6220 if (!atomic_inc_not_zero(&rb->mmap_count))
6223 if (rb_has_aux(rb)) {
6224 atomic_inc(&rb->aux_mmap_count);
6229 atomic_set(&rb->aux_mmap_count, 1);
6230 user_extra = nr_pages;
6236 * If we have rb pages ensure they're a power-of-two number, so we
6237 * can do bitmasks instead of modulo.
6239 if (nr_pages != 0 && !is_power_of_2(nr_pages))
6242 if (vma_size != PAGE_SIZE * (1 + nr_pages))
6245 WARN_ON_ONCE(event->ctx->parent_ctx);
6247 mutex_lock(&event->mmap_mutex);
6249 if (data_page_nr(event->rb) != nr_pages) {
6254 if (!atomic_inc_not_zero(&event->rb->mmap_count)) {
6256 * Raced against perf_mmap_close() through
6257 * perf_event_set_output(). Try again, hope for better
6260 mutex_unlock(&event->mmap_mutex);
6267 user_extra = nr_pages + 1;
6270 user_lock_limit = sysctl_perf_event_mlock >> (PAGE_SHIFT - 10);
6273 * Increase the limit linearly with more CPUs:
6275 user_lock_limit *= num_online_cpus();
6277 user_locked = atomic_long_read(&user->locked_vm);
6280 * sysctl_perf_event_mlock may have changed, so that
6281 * user->locked_vm > user_lock_limit
6283 if (user_locked > user_lock_limit)
6284 user_locked = user_lock_limit;
6285 user_locked += user_extra;
6287 if (user_locked > user_lock_limit) {
6289 * charge locked_vm until it hits user_lock_limit;
6290 * charge the rest from pinned_vm
6292 extra = user_locked - user_lock_limit;
6293 user_extra -= extra;
6296 lock_limit = rlimit(RLIMIT_MEMLOCK);
6297 lock_limit >>= PAGE_SHIFT;
6298 locked = atomic64_read(&vma->vm_mm->pinned_vm) + extra;
6300 if ((locked > lock_limit) && perf_is_paranoid() &&
6301 !capable(CAP_IPC_LOCK)) {
6306 WARN_ON(!rb && event->rb);
6308 if (vma->vm_flags & VM_WRITE)
6309 flags |= RING_BUFFER_WRITABLE;
6312 rb = rb_alloc(nr_pages,
6313 event->attr.watermark ? event->attr.wakeup_watermark : 0,
6321 atomic_set(&rb->mmap_count, 1);
6322 rb->mmap_user = get_current_user();
6323 rb->mmap_locked = extra;
6325 ring_buffer_attach(event, rb);
6327 perf_event_update_time(event);
6328 perf_event_init_userpage(event);
6329 perf_event_update_userpage(event);
6331 ret = rb_alloc_aux(rb, event, vma->vm_pgoff, nr_pages,
6332 event->attr.aux_watermark, flags);
6334 rb->aux_mmap_locked = extra;
6339 atomic_long_add(user_extra, &user->locked_vm);
6340 atomic64_add(extra, &vma->vm_mm->pinned_vm);
6342 atomic_inc(&event->mmap_count);
6344 atomic_dec(&rb->mmap_count);
6347 mutex_unlock(&event->mmap_mutex);
6350 * Since pinned accounting is per vm we cannot allow fork() to copy our
6353 vma->vm_flags |= VM_DONTCOPY | VM_DONTEXPAND | VM_DONTDUMP;
6354 vma->vm_ops = &perf_mmap_vmops;
6356 if (event->pmu->event_mapped)
6357 event->pmu->event_mapped(event, vma->vm_mm);
6362 static int perf_fasync(int fd, struct file *filp, int on)
6364 struct inode *inode = file_inode(filp);
6365 struct perf_event *event = filp->private_data;
6369 retval = fasync_helper(fd, filp, on, &event->fasync);
6370 inode_unlock(inode);
6378 static const struct file_operations perf_fops = {
6379 .llseek = no_llseek,
6380 .release = perf_release,
6383 .unlocked_ioctl = perf_ioctl,
6384 .compat_ioctl = perf_compat_ioctl,
6386 .fasync = perf_fasync,
6392 * If there's data, ensure we set the poll() state and publish everything
6393 * to user-space before waking everybody up.
6396 static inline struct fasync_struct **perf_event_fasync(struct perf_event *event)
6398 /* only the parent has fasync state */
6400 event = event->parent;
6401 return &event->fasync;
6404 void perf_event_wakeup(struct perf_event *event)
6406 ring_buffer_wakeup(event);
6408 if (event->pending_kill) {
6409 kill_fasync(perf_event_fasync(event), SIGIO, event->pending_kill);
6410 event->pending_kill = 0;
6414 static void perf_sigtrap(struct perf_event *event)
6417 * We'd expect this to only occur if the irq_work is delayed and either
6418 * ctx->task or current has changed in the meantime. This can be the
6419 * case on architectures that do not implement arch_irq_work_raise().
6421 if (WARN_ON_ONCE(event->ctx->task != current))
6425 * perf_pending_event() can race with the task exiting.
6427 if (current->flags & PF_EXITING)
6430 send_sig_perf((void __user *)event->pending_addr,
6431 event->attr.type, event->attr.sig_data);
6434 static void perf_pending_event_disable(struct perf_event *event)
6436 int cpu = READ_ONCE(event->pending_disable);
6441 if (cpu == smp_processor_id()) {
6442 WRITE_ONCE(event->pending_disable, -1);
6444 if (event->attr.sigtrap) {
6445 perf_sigtrap(event);
6446 atomic_set_release(&event->event_limit, 1); /* rearm event */
6450 perf_event_disable_local(event);
6457 * perf_event_disable_inatomic()
6458 * @pending_disable = CPU-A;
6462 * @pending_disable = -1;
6465 * perf_event_disable_inatomic()
6466 * @pending_disable = CPU-B;
6467 * irq_work_queue(); // FAILS
6470 * perf_pending_event()
6472 * But the event runs on CPU-B and wants disabling there.
6474 irq_work_queue_on(&event->pending, cpu);
6477 static void perf_pending_event(struct irq_work *entry)
6479 struct perf_event *event = container_of(entry, struct perf_event, pending);
6482 rctx = perf_swevent_get_recursion_context();
6484 * If we 'fail' here, that's OK, it means recursion is already disabled
6485 * and we won't recurse 'further'.
6488 perf_pending_event_disable(event);
6490 if (event->pending_wakeup) {
6491 event->pending_wakeup = 0;
6492 perf_event_wakeup(event);
6496 perf_swevent_put_recursion_context(rctx);
6499 #ifdef CONFIG_GUEST_PERF_EVENTS
6500 struct perf_guest_info_callbacks __rcu *perf_guest_cbs;
6502 DEFINE_STATIC_CALL_RET0(__perf_guest_state, *perf_guest_cbs->state);
6503 DEFINE_STATIC_CALL_RET0(__perf_guest_get_ip, *perf_guest_cbs->get_ip);
6504 DEFINE_STATIC_CALL_RET0(__perf_guest_handle_intel_pt_intr, *perf_guest_cbs->handle_intel_pt_intr);
6506 void perf_register_guest_info_callbacks(struct perf_guest_info_callbacks *cbs)
6508 if (WARN_ON_ONCE(rcu_access_pointer(perf_guest_cbs)))
6511 rcu_assign_pointer(perf_guest_cbs, cbs);
6512 static_call_update(__perf_guest_state, cbs->state);
6513 static_call_update(__perf_guest_get_ip, cbs->get_ip);
6515 /* Implementing ->handle_intel_pt_intr is optional. */
6516 if (cbs->handle_intel_pt_intr)
6517 static_call_update(__perf_guest_handle_intel_pt_intr,
6518 cbs->handle_intel_pt_intr);
6520 EXPORT_SYMBOL_GPL(perf_register_guest_info_callbacks);
6522 void perf_unregister_guest_info_callbacks(struct perf_guest_info_callbacks *cbs)
6524 if (WARN_ON_ONCE(rcu_access_pointer(perf_guest_cbs) != cbs))
6527 rcu_assign_pointer(perf_guest_cbs, NULL);
6528 static_call_update(__perf_guest_state, (void *)&__static_call_return0);
6529 static_call_update(__perf_guest_get_ip, (void *)&__static_call_return0);
6530 static_call_update(__perf_guest_handle_intel_pt_intr,
6531 (void *)&__static_call_return0);
6534 EXPORT_SYMBOL_GPL(perf_unregister_guest_info_callbacks);
6538 perf_output_sample_regs(struct perf_output_handle *handle,
6539 struct pt_regs *regs, u64 mask)
6542 DECLARE_BITMAP(_mask, 64);
6544 bitmap_from_u64(_mask, mask);
6545 for_each_set_bit(bit, _mask, sizeof(mask) * BITS_PER_BYTE) {
6548 val = perf_reg_value(regs, bit);
6549 perf_output_put(handle, val);
6553 static void perf_sample_regs_user(struct perf_regs *regs_user,
6554 struct pt_regs *regs)
6556 if (user_mode(regs)) {
6557 regs_user->abi = perf_reg_abi(current);
6558 regs_user->regs = regs;
6559 } else if (!(current->flags & PF_KTHREAD)) {
6560 perf_get_regs_user(regs_user, regs);
6562 regs_user->abi = PERF_SAMPLE_REGS_ABI_NONE;
6563 regs_user->regs = NULL;
6567 static void perf_sample_regs_intr(struct perf_regs *regs_intr,
6568 struct pt_regs *regs)
6570 regs_intr->regs = regs;
6571 regs_intr->abi = perf_reg_abi(current);
6576 * Get remaining task size from user stack pointer.
6578 * It'd be better to take stack vma map and limit this more
6579 * precisely, but there's no way to get it safely under interrupt,
6580 * so using TASK_SIZE as limit.
6582 static u64 perf_ustack_task_size(struct pt_regs *regs)
6584 unsigned long addr = perf_user_stack_pointer(regs);
6586 if (!addr || addr >= TASK_SIZE)
6589 return TASK_SIZE - addr;
6593 perf_sample_ustack_size(u16 stack_size, u16 header_size,
6594 struct pt_regs *regs)
6598 /* No regs, no stack pointer, no dump. */
6603 * Check if we fit in with the requested stack size into the:
6605 * If we don't, we limit the size to the TASK_SIZE.
6607 * - remaining sample size
6608 * If we don't, we customize the stack size to
6609 * fit in to the remaining sample size.
6612 task_size = min((u64) USHRT_MAX, perf_ustack_task_size(regs));
6613 stack_size = min(stack_size, (u16) task_size);
6615 /* Current header size plus static size and dynamic size. */
6616 header_size += 2 * sizeof(u64);
6618 /* Do we fit in with the current stack dump size? */
6619 if ((u16) (header_size + stack_size) < header_size) {
6621 * If we overflow the maximum size for the sample,
6622 * we customize the stack dump size to fit in.
6624 stack_size = USHRT_MAX - header_size - sizeof(u64);
6625 stack_size = round_up(stack_size, sizeof(u64));
6632 perf_output_sample_ustack(struct perf_output_handle *handle, u64 dump_size,
6633 struct pt_regs *regs)
6635 /* Case of a kernel thread, nothing to dump */
6638 perf_output_put(handle, size);
6647 * - the size requested by user or the best one we can fit
6648 * in to the sample max size
6650 * - user stack dump data
6652 * - the actual dumped size
6656 perf_output_put(handle, dump_size);
6659 sp = perf_user_stack_pointer(regs);
6660 rem = __output_copy_user(handle, (void *) sp, dump_size);
6661 dyn_size = dump_size - rem;
6663 perf_output_skip(handle, rem);
6666 perf_output_put(handle, dyn_size);
6670 static unsigned long perf_prepare_sample_aux(struct perf_event *event,
6671 struct perf_sample_data *data,
6674 struct perf_event *sampler = event->aux_event;
6675 struct perf_buffer *rb;
6682 if (WARN_ON_ONCE(READ_ONCE(sampler->state) != PERF_EVENT_STATE_ACTIVE))
6685 if (WARN_ON_ONCE(READ_ONCE(sampler->oncpu) != smp_processor_id()))
6688 rb = ring_buffer_get(sampler);
6693 * If this is an NMI hit inside sampling code, don't take
6694 * the sample. See also perf_aux_sample_output().
6696 if (READ_ONCE(rb->aux_in_sampling)) {
6699 size = min_t(size_t, size, perf_aux_size(rb));
6700 data->aux_size = ALIGN(size, sizeof(u64));
6702 ring_buffer_put(rb);
6705 return data->aux_size;
6708 static long perf_pmu_snapshot_aux(struct perf_buffer *rb,
6709 struct perf_event *event,
6710 struct perf_output_handle *handle,
6713 unsigned long flags;
6717 * Normal ->start()/->stop() callbacks run in IRQ mode in scheduler
6718 * paths. If we start calling them in NMI context, they may race with
6719 * the IRQ ones, that is, for example, re-starting an event that's just
6720 * been stopped, which is why we're using a separate callback that
6721 * doesn't change the event state.
6723 * IRQs need to be disabled to prevent IPIs from racing with us.
6725 local_irq_save(flags);
6727 * Guard against NMI hits inside the critical section;
6728 * see also perf_prepare_sample_aux().
6730 WRITE_ONCE(rb->aux_in_sampling, 1);
6733 ret = event->pmu->snapshot_aux(event, handle, size);
6736 WRITE_ONCE(rb->aux_in_sampling, 0);
6737 local_irq_restore(flags);
6742 static void perf_aux_sample_output(struct perf_event *event,
6743 struct perf_output_handle *handle,
6744 struct perf_sample_data *data)
6746 struct perf_event *sampler = event->aux_event;
6747 struct perf_buffer *rb;
6751 if (WARN_ON_ONCE(!sampler || !data->aux_size))
6754 rb = ring_buffer_get(sampler);
6758 size = perf_pmu_snapshot_aux(rb, sampler, handle, data->aux_size);
6761 * An error here means that perf_output_copy() failed (returned a
6762 * non-zero surplus that it didn't copy), which in its current
6763 * enlightened implementation is not possible. If that changes, we'd
6766 if (WARN_ON_ONCE(size < 0))
6770 * The pad comes from ALIGN()ing data->aux_size up to u64 in
6771 * perf_prepare_sample_aux(), so should not be more than that.
6773 pad = data->aux_size - size;
6774 if (WARN_ON_ONCE(pad >= sizeof(u64)))
6779 perf_output_copy(handle, &zero, pad);
6783 ring_buffer_put(rb);
6786 static void __perf_event_header__init_id(struct perf_event_header *header,
6787 struct perf_sample_data *data,
6788 struct perf_event *event)
6790 u64 sample_type = event->attr.sample_type;
6792 data->type = sample_type;
6793 header->size += event->id_header_size;
6795 if (sample_type & PERF_SAMPLE_TID) {
6796 /* namespace issues */
6797 data->tid_entry.pid = perf_event_pid(event, current);
6798 data->tid_entry.tid = perf_event_tid(event, current);
6801 if (sample_type & PERF_SAMPLE_TIME)
6802 data->time = perf_event_clock(event);
6804 if (sample_type & (PERF_SAMPLE_ID | PERF_SAMPLE_IDENTIFIER))
6805 data->id = primary_event_id(event);
6807 if (sample_type & PERF_SAMPLE_STREAM_ID)
6808 data->stream_id = event->id;
6810 if (sample_type & PERF_SAMPLE_CPU) {
6811 data->cpu_entry.cpu = raw_smp_processor_id();
6812 data->cpu_entry.reserved = 0;
6816 void perf_event_header__init_id(struct perf_event_header *header,
6817 struct perf_sample_data *data,
6818 struct perf_event *event)
6820 if (event->attr.sample_id_all)
6821 __perf_event_header__init_id(header, data, event);
6824 static void __perf_event__output_id_sample(struct perf_output_handle *handle,
6825 struct perf_sample_data *data)
6827 u64 sample_type = data->type;
6829 if (sample_type & PERF_SAMPLE_TID)
6830 perf_output_put(handle, data->tid_entry);
6832 if (sample_type & PERF_SAMPLE_TIME)
6833 perf_output_put(handle, data->time);
6835 if (sample_type & PERF_SAMPLE_ID)
6836 perf_output_put(handle, data->id);
6838 if (sample_type & PERF_SAMPLE_STREAM_ID)
6839 perf_output_put(handle, data->stream_id);
6841 if (sample_type & PERF_SAMPLE_CPU)
6842 perf_output_put(handle, data->cpu_entry);
6844 if (sample_type & PERF_SAMPLE_IDENTIFIER)
6845 perf_output_put(handle, data->id);
6848 void perf_event__output_id_sample(struct perf_event *event,
6849 struct perf_output_handle *handle,
6850 struct perf_sample_data *sample)
6852 if (event->attr.sample_id_all)
6853 __perf_event__output_id_sample(handle, sample);
6856 static void perf_output_read_one(struct perf_output_handle *handle,
6857 struct perf_event *event,
6858 u64 enabled, u64 running)
6860 u64 read_format = event->attr.read_format;
6864 values[n++] = perf_event_count(event);
6865 if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED) {
6866 values[n++] = enabled +
6867 atomic64_read(&event->child_total_time_enabled);
6869 if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING) {
6870 values[n++] = running +
6871 atomic64_read(&event->child_total_time_running);
6873 if (read_format & PERF_FORMAT_ID)
6874 values[n++] = primary_event_id(event);
6876 __output_copy(handle, values, n * sizeof(u64));
6879 static void perf_output_read_group(struct perf_output_handle *handle,
6880 struct perf_event *event,
6881 u64 enabled, u64 running)
6883 struct perf_event *leader = event->group_leader, *sub;
6884 u64 read_format = event->attr.read_format;
6888 values[n++] = 1 + leader->nr_siblings;
6890 if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED)
6891 values[n++] = enabled;
6893 if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING)
6894 values[n++] = running;
6896 if ((leader != event) &&
6897 (leader->state == PERF_EVENT_STATE_ACTIVE))
6898 leader->pmu->read(leader);
6900 values[n++] = perf_event_count(leader);
6901 if (read_format & PERF_FORMAT_ID)
6902 values[n++] = primary_event_id(leader);
6904 __output_copy(handle, values, n * sizeof(u64));
6906 for_each_sibling_event(sub, leader) {
6909 if ((sub != event) &&
6910 (sub->state == PERF_EVENT_STATE_ACTIVE))
6911 sub->pmu->read(sub);
6913 values[n++] = perf_event_count(sub);
6914 if (read_format & PERF_FORMAT_ID)
6915 values[n++] = primary_event_id(sub);
6917 __output_copy(handle, values, n * sizeof(u64));
6921 #define PERF_FORMAT_TOTAL_TIMES (PERF_FORMAT_TOTAL_TIME_ENABLED|\
6922 PERF_FORMAT_TOTAL_TIME_RUNNING)
6925 * XXX PERF_SAMPLE_READ vs inherited events seems difficult.
6927 * The problem is that its both hard and excessively expensive to iterate the
6928 * child list, not to mention that its impossible to IPI the children running
6929 * on another CPU, from interrupt/NMI context.
6931 static void perf_output_read(struct perf_output_handle *handle,
6932 struct perf_event *event)
6934 u64 enabled = 0, running = 0, now;
6935 u64 read_format = event->attr.read_format;
6938 * compute total_time_enabled, total_time_running
6939 * based on snapshot values taken when the event
6940 * was last scheduled in.
6942 * we cannot simply called update_context_time()
6943 * because of locking issue as we are called in
6946 if (read_format & PERF_FORMAT_TOTAL_TIMES)
6947 calc_timer_values(event, &now, &enabled, &running);
6949 if (event->attr.read_format & PERF_FORMAT_GROUP)
6950 perf_output_read_group(handle, event, enabled, running);
6952 perf_output_read_one(handle, event, enabled, running);
6955 static inline bool perf_sample_save_hw_index(struct perf_event *event)
6957 return event->attr.branch_sample_type & PERF_SAMPLE_BRANCH_HW_INDEX;
6960 void perf_output_sample(struct perf_output_handle *handle,
6961 struct perf_event_header *header,
6962 struct perf_sample_data *data,
6963 struct perf_event *event)
6965 u64 sample_type = data->type;
6967 perf_output_put(handle, *header);
6969 if (sample_type & PERF_SAMPLE_IDENTIFIER)
6970 perf_output_put(handle, data->id);
6972 if (sample_type & PERF_SAMPLE_IP)
6973 perf_output_put(handle, data->ip);
6975 if (sample_type & PERF_SAMPLE_TID)
6976 perf_output_put(handle, data->tid_entry);
6978 if (sample_type & PERF_SAMPLE_TIME)
6979 perf_output_put(handle, data->time);
6981 if (sample_type & PERF_SAMPLE_ADDR)
6982 perf_output_put(handle, data->addr);
6984 if (sample_type & PERF_SAMPLE_ID)
6985 perf_output_put(handle, data->id);
6987 if (sample_type & PERF_SAMPLE_STREAM_ID)
6988 perf_output_put(handle, data->stream_id);
6990 if (sample_type & PERF_SAMPLE_CPU)
6991 perf_output_put(handle, data->cpu_entry);
6993 if (sample_type & PERF_SAMPLE_PERIOD)
6994 perf_output_put(handle, data->period);
6996 if (sample_type & PERF_SAMPLE_READ)
6997 perf_output_read(handle, event);
6999 if (sample_type & PERF_SAMPLE_CALLCHAIN) {
7002 size += data->callchain->nr;
7003 size *= sizeof(u64);
7004 __output_copy(handle, data->callchain, size);
7007 if (sample_type & PERF_SAMPLE_RAW) {
7008 struct perf_raw_record *raw = data->raw;
7011 struct perf_raw_frag *frag = &raw->frag;
7013 perf_output_put(handle, raw->size);
7016 __output_custom(handle, frag->copy,
7017 frag->data, frag->size);
7019 __output_copy(handle, frag->data,
7022 if (perf_raw_frag_last(frag))
7027 __output_skip(handle, NULL, frag->pad);
7033 .size = sizeof(u32),
7036 perf_output_put(handle, raw);
7040 if (sample_type & PERF_SAMPLE_BRANCH_STACK) {
7041 if (data->br_stack) {
7044 size = data->br_stack->nr
7045 * sizeof(struct perf_branch_entry);
7047 perf_output_put(handle, data->br_stack->nr);
7048 if (perf_sample_save_hw_index(event))
7049 perf_output_put(handle, data->br_stack->hw_idx);
7050 perf_output_copy(handle, data->br_stack->entries, size);
7053 * we always store at least the value of nr
7056 perf_output_put(handle, nr);
7060 if (sample_type & PERF_SAMPLE_REGS_USER) {
7061 u64 abi = data->regs_user.abi;
7064 * If there are no regs to dump, notice it through
7065 * first u64 being zero (PERF_SAMPLE_REGS_ABI_NONE).
7067 perf_output_put(handle, abi);
7070 u64 mask = event->attr.sample_regs_user;
7071 perf_output_sample_regs(handle,
7072 data->regs_user.regs,
7077 if (sample_type & PERF_SAMPLE_STACK_USER) {
7078 perf_output_sample_ustack(handle,
7079 data->stack_user_size,
7080 data->regs_user.regs);
7083 if (sample_type & PERF_SAMPLE_WEIGHT_TYPE)
7084 perf_output_put(handle, data->weight.full);
7086 if (sample_type & PERF_SAMPLE_DATA_SRC)
7087 perf_output_put(handle, data->data_src.val);
7089 if (sample_type & PERF_SAMPLE_TRANSACTION)
7090 perf_output_put(handle, data->txn);
7092 if (sample_type & PERF_SAMPLE_REGS_INTR) {
7093 u64 abi = data->regs_intr.abi;
7095 * If there are no regs to dump, notice it through
7096 * first u64 being zero (PERF_SAMPLE_REGS_ABI_NONE).
7098 perf_output_put(handle, abi);
7101 u64 mask = event->attr.sample_regs_intr;
7103 perf_output_sample_regs(handle,
7104 data->regs_intr.regs,
7109 if (sample_type & PERF_SAMPLE_PHYS_ADDR)
7110 perf_output_put(handle, data->phys_addr);
7112 if (sample_type & PERF_SAMPLE_CGROUP)
7113 perf_output_put(handle, data->cgroup);
7115 if (sample_type & PERF_SAMPLE_DATA_PAGE_SIZE)
7116 perf_output_put(handle, data->data_page_size);
7118 if (sample_type & PERF_SAMPLE_CODE_PAGE_SIZE)
7119 perf_output_put(handle, data->code_page_size);
7121 if (sample_type & PERF_SAMPLE_AUX) {
7122 perf_output_put(handle, data->aux_size);
7125 perf_aux_sample_output(event, handle, data);
7128 if (!event->attr.watermark) {
7129 int wakeup_events = event->attr.wakeup_events;
7131 if (wakeup_events) {
7132 struct perf_buffer *rb = handle->rb;
7133 int events = local_inc_return(&rb->events);
7135 if (events >= wakeup_events) {
7136 local_sub(wakeup_events, &rb->events);
7137 local_inc(&rb->wakeup);
7143 static u64 perf_virt_to_phys(u64 virt)
7150 if (virt >= TASK_SIZE) {
7151 /* If it's vmalloc()d memory, leave phys_addr as 0 */
7152 if (virt_addr_valid((void *)(uintptr_t)virt) &&
7153 !(virt >= VMALLOC_START && virt < VMALLOC_END))
7154 phys_addr = (u64)virt_to_phys((void *)(uintptr_t)virt);
7157 * Walking the pages tables for user address.
7158 * Interrupts are disabled, so it prevents any tear down
7159 * of the page tables.
7160 * Try IRQ-safe get_user_page_fast_only first.
7161 * If failed, leave phys_addr as 0.
7163 if (current->mm != NULL) {
7166 pagefault_disable();
7167 if (get_user_page_fast_only(virt, 0, &p)) {
7168 phys_addr = page_to_phys(p) + virt % PAGE_SIZE;
7179 * Return the pagetable size of a given virtual address.
7181 static u64 perf_get_pgtable_size(struct mm_struct *mm, unsigned long addr)
7185 #ifdef CONFIG_HAVE_FAST_GUP
7192 pgdp = pgd_offset(mm, addr);
7193 pgd = READ_ONCE(*pgdp);
7198 return pgd_leaf_size(pgd);
7200 p4dp = p4d_offset_lockless(pgdp, pgd, addr);
7201 p4d = READ_ONCE(*p4dp);
7202 if (!p4d_present(p4d))
7206 return p4d_leaf_size(p4d);
7208 pudp = pud_offset_lockless(p4dp, p4d, addr);
7209 pud = READ_ONCE(*pudp);
7210 if (!pud_present(pud))
7214 return pud_leaf_size(pud);
7216 pmdp = pmd_offset_lockless(pudp, pud, addr);
7217 pmd = READ_ONCE(*pmdp);
7218 if (!pmd_present(pmd))
7222 return pmd_leaf_size(pmd);
7224 ptep = pte_offset_map(&pmd, addr);
7225 pte = ptep_get_lockless(ptep);
7226 if (pte_present(pte))
7227 size = pte_leaf_size(pte);
7229 #endif /* CONFIG_HAVE_FAST_GUP */
7234 static u64 perf_get_page_size(unsigned long addr)
7236 struct mm_struct *mm;
7237 unsigned long flags;
7244 * Software page-table walkers must disable IRQs,
7245 * which prevents any tear down of the page tables.
7247 local_irq_save(flags);
7252 * For kernel threads and the like, use init_mm so that
7253 * we can find kernel memory.
7258 size = perf_get_pgtable_size(mm, addr);
7260 local_irq_restore(flags);
7265 static struct perf_callchain_entry __empty_callchain = { .nr = 0, };
7267 struct perf_callchain_entry *
7268 perf_callchain(struct perf_event *event, struct pt_regs *regs)
7270 bool kernel = !event->attr.exclude_callchain_kernel;
7271 bool user = !event->attr.exclude_callchain_user;
7272 /* Disallow cross-task user callchains. */
7273 bool crosstask = event->ctx->task && event->ctx->task != current;
7274 const u32 max_stack = event->attr.sample_max_stack;
7275 struct perf_callchain_entry *callchain;
7277 if (!kernel && !user)
7278 return &__empty_callchain;
7280 callchain = get_perf_callchain(regs, 0, kernel, user,
7281 max_stack, crosstask, true);
7282 return callchain ?: &__empty_callchain;
7285 void perf_prepare_sample(struct perf_event_header *header,
7286 struct perf_sample_data *data,
7287 struct perf_event *event,
7288 struct pt_regs *regs)
7290 u64 sample_type = event->attr.sample_type;
7292 header->type = PERF_RECORD_SAMPLE;
7293 header->size = sizeof(*header) + event->header_size;
7296 header->misc |= perf_misc_flags(regs);
7298 __perf_event_header__init_id(header, data, event);
7300 if (sample_type & (PERF_SAMPLE_IP | PERF_SAMPLE_CODE_PAGE_SIZE))
7301 data->ip = perf_instruction_pointer(regs);
7303 if (sample_type & PERF_SAMPLE_CALLCHAIN) {
7306 if (!(sample_type & __PERF_SAMPLE_CALLCHAIN_EARLY))
7307 data->callchain = perf_callchain(event, regs);
7309 size += data->callchain->nr;
7311 header->size += size * sizeof(u64);
7314 if (sample_type & PERF_SAMPLE_RAW) {
7315 struct perf_raw_record *raw = data->raw;
7319 struct perf_raw_frag *frag = &raw->frag;
7324 if (perf_raw_frag_last(frag))
7329 size = round_up(sum + sizeof(u32), sizeof(u64));
7330 raw->size = size - sizeof(u32);
7331 frag->pad = raw->size - sum;
7336 header->size += size;
7339 if (sample_type & PERF_SAMPLE_BRANCH_STACK) {
7340 int size = sizeof(u64); /* nr */
7341 if (data->br_stack) {
7342 if (perf_sample_save_hw_index(event))
7343 size += sizeof(u64);
7345 size += data->br_stack->nr
7346 * sizeof(struct perf_branch_entry);
7348 header->size += size;
7351 if (sample_type & (PERF_SAMPLE_REGS_USER | PERF_SAMPLE_STACK_USER))
7352 perf_sample_regs_user(&data->regs_user, regs);
7354 if (sample_type & PERF_SAMPLE_REGS_USER) {
7355 /* regs dump ABI info */
7356 int size = sizeof(u64);
7358 if (data->regs_user.regs) {
7359 u64 mask = event->attr.sample_regs_user;
7360 size += hweight64(mask) * sizeof(u64);
7363 header->size += size;
7366 if (sample_type & PERF_SAMPLE_STACK_USER) {
7368 * Either we need PERF_SAMPLE_STACK_USER bit to be always
7369 * processed as the last one or have additional check added
7370 * in case new sample type is added, because we could eat
7371 * up the rest of the sample size.
7373 u16 stack_size = event->attr.sample_stack_user;
7374 u16 size = sizeof(u64);
7376 stack_size = perf_sample_ustack_size(stack_size, header->size,
7377 data->regs_user.regs);
7380 * If there is something to dump, add space for the dump
7381 * itself and for the field that tells the dynamic size,
7382 * which is how many have been actually dumped.
7385 size += sizeof(u64) + stack_size;
7387 data->stack_user_size = stack_size;
7388 header->size += size;
7391 if (sample_type & PERF_SAMPLE_REGS_INTR) {
7392 /* regs dump ABI info */
7393 int size = sizeof(u64);
7395 perf_sample_regs_intr(&data->regs_intr, regs);
7397 if (data->regs_intr.regs) {
7398 u64 mask = event->attr.sample_regs_intr;
7400 size += hweight64(mask) * sizeof(u64);
7403 header->size += size;
7406 if (sample_type & PERF_SAMPLE_PHYS_ADDR)
7407 data->phys_addr = perf_virt_to_phys(data->addr);
7409 #ifdef CONFIG_CGROUP_PERF
7410 if (sample_type & PERF_SAMPLE_CGROUP) {
7411 struct cgroup *cgrp;
7413 /* protected by RCU */
7414 cgrp = task_css_check(current, perf_event_cgrp_id, 1)->cgroup;
7415 data->cgroup = cgroup_id(cgrp);
7420 * PERF_DATA_PAGE_SIZE requires PERF_SAMPLE_ADDR. If the user doesn't
7421 * require PERF_SAMPLE_ADDR, kernel implicitly retrieve the data->addr,
7422 * but the value will not dump to the userspace.
7424 if (sample_type & PERF_SAMPLE_DATA_PAGE_SIZE)
7425 data->data_page_size = perf_get_page_size(data->addr);
7427 if (sample_type & PERF_SAMPLE_CODE_PAGE_SIZE)
7428 data->code_page_size = perf_get_page_size(data->ip);
7430 if (sample_type & PERF_SAMPLE_AUX) {
7433 header->size += sizeof(u64); /* size */
7436 * Given the 16bit nature of header::size, an AUX sample can
7437 * easily overflow it, what with all the preceding sample bits.
7438 * Make sure this doesn't happen by using up to U16_MAX bytes
7439 * per sample in total (rounded down to 8 byte boundary).
7441 size = min_t(size_t, U16_MAX - header->size,
7442 event->attr.aux_sample_size);
7443 size = rounddown(size, 8);
7444 size = perf_prepare_sample_aux(event, data, size);
7446 WARN_ON_ONCE(size + header->size > U16_MAX);
7447 header->size += size;
7450 * If you're adding more sample types here, you likely need to do
7451 * something about the overflowing header::size, like repurpose the
7452 * lowest 3 bits of size, which should be always zero at the moment.
7453 * This raises a more important question, do we really need 512k sized
7454 * samples and why, so good argumentation is in order for whatever you
7457 WARN_ON_ONCE(header->size & 7);
7460 static __always_inline int
7461 __perf_event_output(struct perf_event *event,
7462 struct perf_sample_data *data,
7463 struct pt_regs *regs,
7464 int (*output_begin)(struct perf_output_handle *,
7465 struct perf_sample_data *,
7466 struct perf_event *,
7469 struct perf_output_handle handle;
7470 struct perf_event_header header;
7473 /* protect the callchain buffers */
7476 perf_prepare_sample(&header, data, event, regs);
7478 err = output_begin(&handle, data, event, header.size);
7482 perf_output_sample(&handle, &header, data, event);
7484 perf_output_end(&handle);
7492 perf_event_output_forward(struct perf_event *event,
7493 struct perf_sample_data *data,
7494 struct pt_regs *regs)
7496 __perf_event_output(event, data, regs, perf_output_begin_forward);
7500 perf_event_output_backward(struct perf_event *event,
7501 struct perf_sample_data *data,
7502 struct pt_regs *regs)
7504 __perf_event_output(event, data, regs, perf_output_begin_backward);
7508 perf_event_output(struct perf_event *event,
7509 struct perf_sample_data *data,
7510 struct pt_regs *regs)
7512 return __perf_event_output(event, data, regs, perf_output_begin);
7519 struct perf_read_event {
7520 struct perf_event_header header;
7527 perf_event_read_event(struct perf_event *event,
7528 struct task_struct *task)
7530 struct perf_output_handle handle;
7531 struct perf_sample_data sample;
7532 struct perf_read_event read_event = {
7534 .type = PERF_RECORD_READ,
7536 .size = sizeof(read_event) + event->read_size,
7538 .pid = perf_event_pid(event, task),
7539 .tid = perf_event_tid(event, task),
7543 perf_event_header__init_id(&read_event.header, &sample, event);
7544 ret = perf_output_begin(&handle, &sample, event, read_event.header.size);
7548 perf_output_put(&handle, read_event);
7549 perf_output_read(&handle, event);
7550 perf_event__output_id_sample(event, &handle, &sample);
7552 perf_output_end(&handle);
7555 typedef void (perf_iterate_f)(struct perf_event *event, void *data);
7558 perf_iterate_ctx(struct perf_event_context *ctx,
7559 perf_iterate_f output,
7560 void *data, bool all)
7562 struct perf_event *event;
7564 list_for_each_entry_rcu(event, &ctx->event_list, event_entry) {
7566 if (event->state < PERF_EVENT_STATE_INACTIVE)
7568 if (!event_filter_match(event))
7572 output(event, data);
7576 static void perf_iterate_sb_cpu(perf_iterate_f output, void *data)
7578 struct pmu_event_list *pel = this_cpu_ptr(&pmu_sb_events);
7579 struct perf_event *event;
7581 list_for_each_entry_rcu(event, &pel->list, sb_list) {
7583 * Skip events that are not fully formed yet; ensure that
7584 * if we observe event->ctx, both event and ctx will be
7585 * complete enough. See perf_install_in_context().
7587 if (!smp_load_acquire(&event->ctx))
7590 if (event->state < PERF_EVENT_STATE_INACTIVE)
7592 if (!event_filter_match(event))
7594 output(event, data);
7599 * Iterate all events that need to receive side-band events.
7601 * For new callers; ensure that account_pmu_sb_event() includes
7602 * your event, otherwise it might not get delivered.
7605 perf_iterate_sb(perf_iterate_f output, void *data,
7606 struct perf_event_context *task_ctx)
7608 struct perf_event_context *ctx;
7615 * If we have task_ctx != NULL we only notify the task context itself.
7616 * The task_ctx is set only for EXIT events before releasing task
7620 perf_iterate_ctx(task_ctx, output, data, false);
7624 perf_iterate_sb_cpu(output, data);
7626 for_each_task_context_nr(ctxn) {
7627 ctx = rcu_dereference(current->perf_event_ctxp[ctxn]);
7629 perf_iterate_ctx(ctx, output, data, false);
7637 * Clear all file-based filters at exec, they'll have to be
7638 * re-instated when/if these objects are mmapped again.
7640 static void perf_event_addr_filters_exec(struct perf_event *event, void *data)
7642 struct perf_addr_filters_head *ifh = perf_event_addr_filters(event);
7643 struct perf_addr_filter *filter;
7644 unsigned int restart = 0, count = 0;
7645 unsigned long flags;
7647 if (!has_addr_filter(event))
7650 raw_spin_lock_irqsave(&ifh->lock, flags);
7651 list_for_each_entry(filter, &ifh->list, entry) {
7652 if (filter->path.dentry) {
7653 event->addr_filter_ranges[count].start = 0;
7654 event->addr_filter_ranges[count].size = 0;
7662 event->addr_filters_gen++;
7663 raw_spin_unlock_irqrestore(&ifh->lock, flags);
7666 perf_event_stop(event, 1);
7669 void perf_event_exec(void)
7671 struct perf_event_context *ctx;
7674 for_each_task_context_nr(ctxn) {
7675 perf_event_enable_on_exec(ctxn);
7676 perf_event_remove_on_exec(ctxn);
7679 ctx = rcu_dereference(current->perf_event_ctxp[ctxn]);
7681 perf_iterate_ctx(ctx, perf_event_addr_filters_exec,
7688 struct remote_output {
7689 struct perf_buffer *rb;
7693 static void __perf_event_output_stop(struct perf_event *event, void *data)
7695 struct perf_event *parent = event->parent;
7696 struct remote_output *ro = data;
7697 struct perf_buffer *rb = ro->rb;
7698 struct stop_event_data sd = {
7702 if (!has_aux(event))
7709 * In case of inheritance, it will be the parent that links to the
7710 * ring-buffer, but it will be the child that's actually using it.
7712 * We are using event::rb to determine if the event should be stopped,
7713 * however this may race with ring_buffer_attach() (through set_output),
7714 * which will make us skip the event that actually needs to be stopped.
7715 * So ring_buffer_attach() has to stop an aux event before re-assigning
7718 if (rcu_dereference(parent->rb) == rb)
7719 ro->err = __perf_event_stop(&sd);
7722 static int __perf_pmu_output_stop(void *info)
7724 struct perf_event *event = info;
7725 struct pmu *pmu = event->ctx->pmu;
7726 struct perf_cpu_context *cpuctx = this_cpu_ptr(pmu->pmu_cpu_context);
7727 struct remote_output ro = {
7732 perf_iterate_ctx(&cpuctx->ctx, __perf_event_output_stop, &ro, false);
7733 if (cpuctx->task_ctx)
7734 perf_iterate_ctx(cpuctx->task_ctx, __perf_event_output_stop,
7741 static void perf_pmu_output_stop(struct perf_event *event)
7743 struct perf_event *iter;
7748 list_for_each_entry_rcu(iter, &event->rb->event_list, rb_entry) {
7750 * For per-CPU events, we need to make sure that neither they
7751 * nor their children are running; for cpu==-1 events it's
7752 * sufficient to stop the event itself if it's active, since
7753 * it can't have children.
7757 cpu = READ_ONCE(iter->oncpu);
7762 err = cpu_function_call(cpu, __perf_pmu_output_stop, event);
7763 if (err == -EAGAIN) {
7772 * task tracking -- fork/exit
7774 * enabled by: attr.comm | attr.mmap | attr.mmap2 | attr.mmap_data | attr.task
7777 struct perf_task_event {
7778 struct task_struct *task;
7779 struct perf_event_context *task_ctx;
7782 struct perf_event_header header;
7792 static int perf_event_task_match(struct perf_event *event)
7794 return event->attr.comm || event->attr.mmap ||
7795 event->attr.mmap2 || event->attr.mmap_data ||
7799 static void perf_event_task_output(struct perf_event *event,
7802 struct perf_task_event *task_event = data;
7803 struct perf_output_handle handle;
7804 struct perf_sample_data sample;
7805 struct task_struct *task = task_event->task;
7806 int ret, size = task_event->event_id.header.size;
7808 if (!perf_event_task_match(event))
7811 perf_event_header__init_id(&task_event->event_id.header, &sample, event);
7813 ret = perf_output_begin(&handle, &sample, event,
7814 task_event->event_id.header.size);
7818 task_event->event_id.pid = perf_event_pid(event, task);
7819 task_event->event_id.tid = perf_event_tid(event, task);
7821 if (task_event->event_id.header.type == PERF_RECORD_EXIT) {
7822 task_event->event_id.ppid = perf_event_pid(event,
7824 task_event->event_id.ptid = perf_event_pid(event,
7826 } else { /* PERF_RECORD_FORK */
7827 task_event->event_id.ppid = perf_event_pid(event, current);
7828 task_event->event_id.ptid = perf_event_tid(event, current);
7831 task_event->event_id.time = perf_event_clock(event);
7833 perf_output_put(&handle, task_event->event_id);
7835 perf_event__output_id_sample(event, &handle, &sample);
7837 perf_output_end(&handle);
7839 task_event->event_id.header.size = size;
7842 static void perf_event_task(struct task_struct *task,
7843 struct perf_event_context *task_ctx,
7846 struct perf_task_event task_event;
7848 if (!atomic_read(&nr_comm_events) &&
7849 !atomic_read(&nr_mmap_events) &&
7850 !atomic_read(&nr_task_events))
7853 task_event = (struct perf_task_event){
7855 .task_ctx = task_ctx,
7858 .type = new ? PERF_RECORD_FORK : PERF_RECORD_EXIT,
7860 .size = sizeof(task_event.event_id),
7870 perf_iterate_sb(perf_event_task_output,
7875 void perf_event_fork(struct task_struct *task)
7877 perf_event_task(task, NULL, 1);
7878 perf_event_namespaces(task);
7885 struct perf_comm_event {
7886 struct task_struct *task;
7891 struct perf_event_header header;
7898 static int perf_event_comm_match(struct perf_event *event)
7900 return event->attr.comm;
7903 static void perf_event_comm_output(struct perf_event *event,
7906 struct perf_comm_event *comm_event = data;
7907 struct perf_output_handle handle;
7908 struct perf_sample_data sample;
7909 int size = comm_event->event_id.header.size;
7912 if (!perf_event_comm_match(event))
7915 perf_event_header__init_id(&comm_event->event_id.header, &sample, event);
7916 ret = perf_output_begin(&handle, &sample, event,
7917 comm_event->event_id.header.size);
7922 comm_event->event_id.pid = perf_event_pid(event, comm_event->task);
7923 comm_event->event_id.tid = perf_event_tid(event, comm_event->task);
7925 perf_output_put(&handle, comm_event->event_id);
7926 __output_copy(&handle, comm_event->comm,
7927 comm_event->comm_size);
7929 perf_event__output_id_sample(event, &handle, &sample);
7931 perf_output_end(&handle);
7933 comm_event->event_id.header.size = size;
7936 static void perf_event_comm_event(struct perf_comm_event *comm_event)
7938 char comm[TASK_COMM_LEN];
7941 memset(comm, 0, sizeof(comm));
7942 strlcpy(comm, comm_event->task->comm, sizeof(comm));
7943 size = ALIGN(strlen(comm)+1, sizeof(u64));
7945 comm_event->comm = comm;
7946 comm_event->comm_size = size;
7948 comm_event->event_id.header.size = sizeof(comm_event->event_id) + size;
7950 perf_iterate_sb(perf_event_comm_output,
7955 void perf_event_comm(struct task_struct *task, bool exec)
7957 struct perf_comm_event comm_event;
7959 if (!atomic_read(&nr_comm_events))
7962 comm_event = (struct perf_comm_event){
7968 .type = PERF_RECORD_COMM,
7969 .misc = exec ? PERF_RECORD_MISC_COMM_EXEC : 0,
7977 perf_event_comm_event(&comm_event);
7981 * namespaces tracking
7984 struct perf_namespaces_event {
7985 struct task_struct *task;
7988 struct perf_event_header header;
7993 struct perf_ns_link_info link_info[NR_NAMESPACES];
7997 static int perf_event_namespaces_match(struct perf_event *event)
7999 return event->attr.namespaces;
8002 static void perf_event_namespaces_output(struct perf_event *event,
8005 struct perf_namespaces_event *namespaces_event = data;
8006 struct perf_output_handle handle;
8007 struct perf_sample_data sample;
8008 u16 header_size = namespaces_event->event_id.header.size;
8011 if (!perf_event_namespaces_match(event))
8014 perf_event_header__init_id(&namespaces_event->event_id.header,
8016 ret = perf_output_begin(&handle, &sample, event,
8017 namespaces_event->event_id.header.size);
8021 namespaces_event->event_id.pid = perf_event_pid(event,
8022 namespaces_event->task);
8023 namespaces_event->event_id.tid = perf_event_tid(event,
8024 namespaces_event->task);
8026 perf_output_put(&handle, namespaces_event->event_id);
8028 perf_event__output_id_sample(event, &handle, &sample);
8030 perf_output_end(&handle);
8032 namespaces_event->event_id.header.size = header_size;
8035 static void perf_fill_ns_link_info(struct perf_ns_link_info *ns_link_info,
8036 struct task_struct *task,
8037 const struct proc_ns_operations *ns_ops)
8039 struct path ns_path;
8040 struct inode *ns_inode;
8043 error = ns_get_path(&ns_path, task, ns_ops);
8045 ns_inode = ns_path.dentry->d_inode;
8046 ns_link_info->dev = new_encode_dev(ns_inode->i_sb->s_dev);
8047 ns_link_info->ino = ns_inode->i_ino;
8052 void perf_event_namespaces(struct task_struct *task)
8054 struct perf_namespaces_event namespaces_event;
8055 struct perf_ns_link_info *ns_link_info;
8057 if (!atomic_read(&nr_namespaces_events))
8060 namespaces_event = (struct perf_namespaces_event){
8064 .type = PERF_RECORD_NAMESPACES,
8066 .size = sizeof(namespaces_event.event_id),
8070 .nr_namespaces = NR_NAMESPACES,
8071 /* .link_info[NR_NAMESPACES] */
8075 ns_link_info = namespaces_event.event_id.link_info;
8077 perf_fill_ns_link_info(&ns_link_info[MNT_NS_INDEX],
8078 task, &mntns_operations);
8080 #ifdef CONFIG_USER_NS
8081 perf_fill_ns_link_info(&ns_link_info[USER_NS_INDEX],
8082 task, &userns_operations);
8084 #ifdef CONFIG_NET_NS
8085 perf_fill_ns_link_info(&ns_link_info[NET_NS_INDEX],
8086 task, &netns_operations);
8088 #ifdef CONFIG_UTS_NS
8089 perf_fill_ns_link_info(&ns_link_info[UTS_NS_INDEX],
8090 task, &utsns_operations);
8092 #ifdef CONFIG_IPC_NS
8093 perf_fill_ns_link_info(&ns_link_info[IPC_NS_INDEX],
8094 task, &ipcns_operations);
8096 #ifdef CONFIG_PID_NS
8097 perf_fill_ns_link_info(&ns_link_info[PID_NS_INDEX],
8098 task, &pidns_operations);
8100 #ifdef CONFIG_CGROUPS
8101 perf_fill_ns_link_info(&ns_link_info[CGROUP_NS_INDEX],
8102 task, &cgroupns_operations);
8105 perf_iterate_sb(perf_event_namespaces_output,
8113 #ifdef CONFIG_CGROUP_PERF
8115 struct perf_cgroup_event {
8119 struct perf_event_header header;
8125 static int perf_event_cgroup_match(struct perf_event *event)
8127 return event->attr.cgroup;
8130 static void perf_event_cgroup_output(struct perf_event *event, void *data)
8132 struct perf_cgroup_event *cgroup_event = data;
8133 struct perf_output_handle handle;
8134 struct perf_sample_data sample;
8135 u16 header_size = cgroup_event->event_id.header.size;
8138 if (!perf_event_cgroup_match(event))
8141 perf_event_header__init_id(&cgroup_event->event_id.header,
8143 ret = perf_output_begin(&handle, &sample, event,
8144 cgroup_event->event_id.header.size);
8148 perf_output_put(&handle, cgroup_event->event_id);
8149 __output_copy(&handle, cgroup_event->path, cgroup_event->path_size);
8151 perf_event__output_id_sample(event, &handle, &sample);
8153 perf_output_end(&handle);
8155 cgroup_event->event_id.header.size = header_size;
8158 static void perf_event_cgroup(struct cgroup *cgrp)
8160 struct perf_cgroup_event cgroup_event;
8161 char path_enomem[16] = "//enomem";
8165 if (!atomic_read(&nr_cgroup_events))
8168 cgroup_event = (struct perf_cgroup_event){
8171 .type = PERF_RECORD_CGROUP,
8173 .size = sizeof(cgroup_event.event_id),
8175 .id = cgroup_id(cgrp),
8179 pathname = kmalloc(PATH_MAX, GFP_KERNEL);
8180 if (pathname == NULL) {
8181 cgroup_event.path = path_enomem;
8183 /* just to be sure to have enough space for alignment */
8184 cgroup_path(cgrp, pathname, PATH_MAX - sizeof(u64));
8185 cgroup_event.path = pathname;
8189 * Since our buffer works in 8 byte units we need to align our string
8190 * size to a multiple of 8. However, we must guarantee the tail end is
8191 * zero'd out to avoid leaking random bits to userspace.
8193 size = strlen(cgroup_event.path) + 1;
8194 while (!IS_ALIGNED(size, sizeof(u64)))
8195 cgroup_event.path[size++] = '\0';
8197 cgroup_event.event_id.header.size += size;
8198 cgroup_event.path_size = size;
8200 perf_iterate_sb(perf_event_cgroup_output,
8213 struct perf_mmap_event {
8214 struct vm_area_struct *vma;
8216 const char *file_name;
8222 u8 build_id[BUILD_ID_SIZE_MAX];
8226 struct perf_event_header header;
8236 static int perf_event_mmap_match(struct perf_event *event,
8239 struct perf_mmap_event *mmap_event = data;
8240 struct vm_area_struct *vma = mmap_event->vma;
8241 int executable = vma->vm_flags & VM_EXEC;
8243 return (!executable && event->attr.mmap_data) ||
8244 (executable && (event->attr.mmap || event->attr.mmap2));
8247 static void perf_event_mmap_output(struct perf_event *event,
8250 struct perf_mmap_event *mmap_event = data;
8251 struct perf_output_handle handle;
8252 struct perf_sample_data sample;
8253 int size = mmap_event->event_id.header.size;
8254 u32 type = mmap_event->event_id.header.type;
8258 if (!perf_event_mmap_match(event, data))
8261 if (event->attr.mmap2) {
8262 mmap_event->event_id.header.type = PERF_RECORD_MMAP2;
8263 mmap_event->event_id.header.size += sizeof(mmap_event->maj);
8264 mmap_event->event_id.header.size += sizeof(mmap_event->min);
8265 mmap_event->event_id.header.size += sizeof(mmap_event->ino);
8266 mmap_event->event_id.header.size += sizeof(mmap_event->ino_generation);
8267 mmap_event->event_id.header.size += sizeof(mmap_event->prot);
8268 mmap_event->event_id.header.size += sizeof(mmap_event->flags);
8271 perf_event_header__init_id(&mmap_event->event_id.header, &sample, event);
8272 ret = perf_output_begin(&handle, &sample, event,
8273 mmap_event->event_id.header.size);
8277 mmap_event->event_id.pid = perf_event_pid(event, current);
8278 mmap_event->event_id.tid = perf_event_tid(event, current);
8280 use_build_id = event->attr.build_id && mmap_event->build_id_size;
8282 if (event->attr.mmap2 && use_build_id)
8283 mmap_event->event_id.header.misc |= PERF_RECORD_MISC_MMAP_BUILD_ID;
8285 perf_output_put(&handle, mmap_event->event_id);
8287 if (event->attr.mmap2) {
8289 u8 size[4] = { (u8) mmap_event->build_id_size, 0, 0, 0 };
8291 __output_copy(&handle, size, 4);
8292 __output_copy(&handle, mmap_event->build_id, BUILD_ID_SIZE_MAX);
8294 perf_output_put(&handle, mmap_event->maj);
8295 perf_output_put(&handle, mmap_event->min);
8296 perf_output_put(&handle, mmap_event->ino);
8297 perf_output_put(&handle, mmap_event->ino_generation);
8299 perf_output_put(&handle, mmap_event->prot);
8300 perf_output_put(&handle, mmap_event->flags);
8303 __output_copy(&handle, mmap_event->file_name,
8304 mmap_event->file_size);
8306 perf_event__output_id_sample(event, &handle, &sample);
8308 perf_output_end(&handle);
8310 mmap_event->event_id.header.size = size;
8311 mmap_event->event_id.header.type = type;
8314 static void perf_event_mmap_event(struct perf_mmap_event *mmap_event)
8316 struct vm_area_struct *vma = mmap_event->vma;
8317 struct file *file = vma->vm_file;
8318 int maj = 0, min = 0;
8319 u64 ino = 0, gen = 0;
8320 u32 prot = 0, flags = 0;
8326 if (vma->vm_flags & VM_READ)
8328 if (vma->vm_flags & VM_WRITE)
8330 if (vma->vm_flags & VM_EXEC)
8333 if (vma->vm_flags & VM_MAYSHARE)
8336 flags = MAP_PRIVATE;
8338 if (vma->vm_flags & VM_LOCKED)
8339 flags |= MAP_LOCKED;
8340 if (is_vm_hugetlb_page(vma))
8341 flags |= MAP_HUGETLB;
8344 struct inode *inode;
8347 buf = kmalloc(PATH_MAX, GFP_KERNEL);
8353 * d_path() works from the end of the rb backwards, so we
8354 * need to add enough zero bytes after the string to handle
8355 * the 64bit alignment we do later.
8357 name = file_path(file, buf, PATH_MAX - sizeof(u64));
8362 inode = file_inode(vma->vm_file);
8363 dev = inode->i_sb->s_dev;
8365 gen = inode->i_generation;
8371 if (vma->vm_ops && vma->vm_ops->name) {
8372 name = (char *) vma->vm_ops->name(vma);
8377 name = (char *)arch_vma_name(vma);
8381 if (vma->vm_start <= vma->vm_mm->start_brk &&
8382 vma->vm_end >= vma->vm_mm->brk) {
8386 if (vma->vm_start <= vma->vm_mm->start_stack &&
8387 vma->vm_end >= vma->vm_mm->start_stack) {
8397 strlcpy(tmp, name, sizeof(tmp));
8401 * Since our buffer works in 8 byte units we need to align our string
8402 * size to a multiple of 8. However, we must guarantee the tail end is
8403 * zero'd out to avoid leaking random bits to userspace.
8405 size = strlen(name)+1;
8406 while (!IS_ALIGNED(size, sizeof(u64)))
8407 name[size++] = '\0';
8409 mmap_event->file_name = name;
8410 mmap_event->file_size = size;
8411 mmap_event->maj = maj;
8412 mmap_event->min = min;
8413 mmap_event->ino = ino;
8414 mmap_event->ino_generation = gen;
8415 mmap_event->prot = prot;
8416 mmap_event->flags = flags;
8418 if (!(vma->vm_flags & VM_EXEC))
8419 mmap_event->event_id.header.misc |= PERF_RECORD_MISC_MMAP_DATA;
8421 mmap_event->event_id.header.size = sizeof(mmap_event->event_id) + size;
8423 if (atomic_read(&nr_build_id_events))
8424 build_id_parse(vma, mmap_event->build_id, &mmap_event->build_id_size);
8426 perf_iterate_sb(perf_event_mmap_output,
8434 * Check whether inode and address range match filter criteria.
8436 static bool perf_addr_filter_match(struct perf_addr_filter *filter,
8437 struct file *file, unsigned long offset,
8440 /* d_inode(NULL) won't be equal to any mapped user-space file */
8441 if (!filter->path.dentry)
8444 if (d_inode(filter->path.dentry) != file_inode(file))
8447 if (filter->offset > offset + size)
8450 if (filter->offset + filter->size < offset)
8456 static bool perf_addr_filter_vma_adjust(struct perf_addr_filter *filter,
8457 struct vm_area_struct *vma,
8458 struct perf_addr_filter_range *fr)
8460 unsigned long vma_size = vma->vm_end - vma->vm_start;
8461 unsigned long off = vma->vm_pgoff << PAGE_SHIFT;
8462 struct file *file = vma->vm_file;
8464 if (!perf_addr_filter_match(filter, file, off, vma_size))
8467 if (filter->offset < off) {
8468 fr->start = vma->vm_start;
8469 fr->size = min(vma_size, filter->size - (off - filter->offset));
8471 fr->start = vma->vm_start + filter->offset - off;
8472 fr->size = min(vma->vm_end - fr->start, filter->size);
8478 static void __perf_addr_filters_adjust(struct perf_event *event, void *data)
8480 struct perf_addr_filters_head *ifh = perf_event_addr_filters(event);
8481 struct vm_area_struct *vma = data;
8482 struct perf_addr_filter *filter;
8483 unsigned int restart = 0, count = 0;
8484 unsigned long flags;
8486 if (!has_addr_filter(event))
8492 raw_spin_lock_irqsave(&ifh->lock, flags);
8493 list_for_each_entry(filter, &ifh->list, entry) {
8494 if (perf_addr_filter_vma_adjust(filter, vma,
8495 &event->addr_filter_ranges[count]))
8502 event->addr_filters_gen++;
8503 raw_spin_unlock_irqrestore(&ifh->lock, flags);
8506 perf_event_stop(event, 1);
8510 * Adjust all task's events' filters to the new vma
8512 static void perf_addr_filters_adjust(struct vm_area_struct *vma)
8514 struct perf_event_context *ctx;
8518 * Data tracing isn't supported yet and as such there is no need
8519 * to keep track of anything that isn't related to executable code:
8521 if (!(vma->vm_flags & VM_EXEC))
8525 for_each_task_context_nr(ctxn) {
8526 ctx = rcu_dereference(current->perf_event_ctxp[ctxn]);
8530 perf_iterate_ctx(ctx, __perf_addr_filters_adjust, vma, true);
8535 void perf_event_mmap(struct vm_area_struct *vma)
8537 struct perf_mmap_event mmap_event;
8539 if (!atomic_read(&nr_mmap_events))
8542 mmap_event = (struct perf_mmap_event){
8548 .type = PERF_RECORD_MMAP,
8549 .misc = PERF_RECORD_MISC_USER,
8554 .start = vma->vm_start,
8555 .len = vma->vm_end - vma->vm_start,
8556 .pgoff = (u64)vma->vm_pgoff << PAGE_SHIFT,
8558 /* .maj (attr_mmap2 only) */
8559 /* .min (attr_mmap2 only) */
8560 /* .ino (attr_mmap2 only) */
8561 /* .ino_generation (attr_mmap2 only) */
8562 /* .prot (attr_mmap2 only) */
8563 /* .flags (attr_mmap2 only) */
8566 perf_addr_filters_adjust(vma);
8567 perf_event_mmap_event(&mmap_event);
8570 void perf_event_aux_event(struct perf_event *event, unsigned long head,
8571 unsigned long size, u64 flags)
8573 struct perf_output_handle handle;
8574 struct perf_sample_data sample;
8575 struct perf_aux_event {
8576 struct perf_event_header header;
8582 .type = PERF_RECORD_AUX,
8584 .size = sizeof(rec),
8592 perf_event_header__init_id(&rec.header, &sample, event);
8593 ret = perf_output_begin(&handle, &sample, event, rec.header.size);
8598 perf_output_put(&handle, rec);
8599 perf_event__output_id_sample(event, &handle, &sample);
8601 perf_output_end(&handle);
8605 * Lost/dropped samples logging
8607 void perf_log_lost_samples(struct perf_event *event, u64 lost)
8609 struct perf_output_handle handle;
8610 struct perf_sample_data sample;
8614 struct perf_event_header header;
8616 } lost_samples_event = {
8618 .type = PERF_RECORD_LOST_SAMPLES,
8620 .size = sizeof(lost_samples_event),
8625 perf_event_header__init_id(&lost_samples_event.header, &sample, event);
8627 ret = perf_output_begin(&handle, &sample, event,
8628 lost_samples_event.header.size);
8632 perf_output_put(&handle, lost_samples_event);
8633 perf_event__output_id_sample(event, &handle, &sample);
8634 perf_output_end(&handle);
8638 * context_switch tracking
8641 struct perf_switch_event {
8642 struct task_struct *task;
8643 struct task_struct *next_prev;
8646 struct perf_event_header header;
8652 static int perf_event_switch_match(struct perf_event *event)
8654 return event->attr.context_switch;
8657 static void perf_event_switch_output(struct perf_event *event, void *data)
8659 struct perf_switch_event *se = data;
8660 struct perf_output_handle handle;
8661 struct perf_sample_data sample;
8664 if (!perf_event_switch_match(event))
8667 /* Only CPU-wide events are allowed to see next/prev pid/tid */
8668 if (event->ctx->task) {
8669 se->event_id.header.type = PERF_RECORD_SWITCH;
8670 se->event_id.header.size = sizeof(se->event_id.header);
8672 se->event_id.header.type = PERF_RECORD_SWITCH_CPU_WIDE;
8673 se->event_id.header.size = sizeof(se->event_id);
8674 se->event_id.next_prev_pid =
8675 perf_event_pid(event, se->next_prev);
8676 se->event_id.next_prev_tid =
8677 perf_event_tid(event, se->next_prev);
8680 perf_event_header__init_id(&se->event_id.header, &sample, event);
8682 ret = perf_output_begin(&handle, &sample, event, se->event_id.header.size);
8686 if (event->ctx->task)
8687 perf_output_put(&handle, se->event_id.header);
8689 perf_output_put(&handle, se->event_id);
8691 perf_event__output_id_sample(event, &handle, &sample);
8693 perf_output_end(&handle);
8696 static void perf_event_switch(struct task_struct *task,
8697 struct task_struct *next_prev, bool sched_in)
8699 struct perf_switch_event switch_event;
8701 /* N.B. caller checks nr_switch_events != 0 */
8703 switch_event = (struct perf_switch_event){
8705 .next_prev = next_prev,
8709 .misc = sched_in ? 0 : PERF_RECORD_MISC_SWITCH_OUT,
8712 /* .next_prev_pid */
8713 /* .next_prev_tid */
8717 if (!sched_in && task->on_rq) {
8718 switch_event.event_id.header.misc |=
8719 PERF_RECORD_MISC_SWITCH_OUT_PREEMPT;
8722 perf_iterate_sb(perf_event_switch_output, &switch_event, NULL);
8726 * IRQ throttle logging
8729 static void perf_log_throttle(struct perf_event *event, int enable)
8731 struct perf_output_handle handle;
8732 struct perf_sample_data sample;
8736 struct perf_event_header header;
8740 } throttle_event = {
8742 .type = PERF_RECORD_THROTTLE,
8744 .size = sizeof(throttle_event),
8746 .time = perf_event_clock(event),
8747 .id = primary_event_id(event),
8748 .stream_id = event->id,
8752 throttle_event.header.type = PERF_RECORD_UNTHROTTLE;
8754 perf_event_header__init_id(&throttle_event.header, &sample, event);
8756 ret = perf_output_begin(&handle, &sample, event,
8757 throttle_event.header.size);
8761 perf_output_put(&handle, throttle_event);
8762 perf_event__output_id_sample(event, &handle, &sample);
8763 perf_output_end(&handle);
8767 * ksymbol register/unregister tracking
8770 struct perf_ksymbol_event {
8774 struct perf_event_header header;
8782 static int perf_event_ksymbol_match(struct perf_event *event)
8784 return event->attr.ksymbol;
8787 static void perf_event_ksymbol_output(struct perf_event *event, void *data)
8789 struct perf_ksymbol_event *ksymbol_event = data;
8790 struct perf_output_handle handle;
8791 struct perf_sample_data sample;
8794 if (!perf_event_ksymbol_match(event))
8797 perf_event_header__init_id(&ksymbol_event->event_id.header,
8799 ret = perf_output_begin(&handle, &sample, event,
8800 ksymbol_event->event_id.header.size);
8804 perf_output_put(&handle, ksymbol_event->event_id);
8805 __output_copy(&handle, ksymbol_event->name, ksymbol_event->name_len);
8806 perf_event__output_id_sample(event, &handle, &sample);
8808 perf_output_end(&handle);
8811 void perf_event_ksymbol(u16 ksym_type, u64 addr, u32 len, bool unregister,
8814 struct perf_ksymbol_event ksymbol_event;
8815 char name[KSYM_NAME_LEN];
8819 if (!atomic_read(&nr_ksymbol_events))
8822 if (ksym_type >= PERF_RECORD_KSYMBOL_TYPE_MAX ||
8823 ksym_type == PERF_RECORD_KSYMBOL_TYPE_UNKNOWN)
8826 strlcpy(name, sym, KSYM_NAME_LEN);
8827 name_len = strlen(name) + 1;
8828 while (!IS_ALIGNED(name_len, sizeof(u64)))
8829 name[name_len++] = '\0';
8830 BUILD_BUG_ON(KSYM_NAME_LEN % sizeof(u64));
8833 flags |= PERF_RECORD_KSYMBOL_FLAGS_UNREGISTER;
8835 ksymbol_event = (struct perf_ksymbol_event){
8837 .name_len = name_len,
8840 .type = PERF_RECORD_KSYMBOL,
8841 .size = sizeof(ksymbol_event.event_id) +
8846 .ksym_type = ksym_type,
8851 perf_iterate_sb(perf_event_ksymbol_output, &ksymbol_event, NULL);
8854 WARN_ONCE(1, "%s: Invalid KSYMBOL type 0x%x\n", __func__, ksym_type);
8858 * bpf program load/unload tracking
8861 struct perf_bpf_event {
8862 struct bpf_prog *prog;
8864 struct perf_event_header header;
8868 u8 tag[BPF_TAG_SIZE];
8872 static int perf_event_bpf_match(struct perf_event *event)
8874 return event->attr.bpf_event;
8877 static void perf_event_bpf_output(struct perf_event *event, void *data)
8879 struct perf_bpf_event *bpf_event = data;
8880 struct perf_output_handle handle;
8881 struct perf_sample_data sample;
8884 if (!perf_event_bpf_match(event))
8887 perf_event_header__init_id(&bpf_event->event_id.header,
8889 ret = perf_output_begin(&handle, data, event,
8890 bpf_event->event_id.header.size);
8894 perf_output_put(&handle, bpf_event->event_id);
8895 perf_event__output_id_sample(event, &handle, &sample);
8897 perf_output_end(&handle);
8900 static void perf_event_bpf_emit_ksymbols(struct bpf_prog *prog,
8901 enum perf_bpf_event_type type)
8903 bool unregister = type == PERF_BPF_EVENT_PROG_UNLOAD;
8906 if (prog->aux->func_cnt == 0) {
8907 perf_event_ksymbol(PERF_RECORD_KSYMBOL_TYPE_BPF,
8908 (u64)(unsigned long)prog->bpf_func,
8909 prog->jited_len, unregister,
8910 prog->aux->ksym.name);
8912 for (i = 0; i < prog->aux->func_cnt; i++) {
8913 struct bpf_prog *subprog = prog->aux->func[i];
8916 PERF_RECORD_KSYMBOL_TYPE_BPF,
8917 (u64)(unsigned long)subprog->bpf_func,
8918 subprog->jited_len, unregister,
8919 prog->aux->ksym.name);
8924 void perf_event_bpf_event(struct bpf_prog *prog,
8925 enum perf_bpf_event_type type,
8928 struct perf_bpf_event bpf_event;
8930 if (type <= PERF_BPF_EVENT_UNKNOWN ||
8931 type >= PERF_BPF_EVENT_MAX)
8935 case PERF_BPF_EVENT_PROG_LOAD:
8936 case PERF_BPF_EVENT_PROG_UNLOAD:
8937 if (atomic_read(&nr_ksymbol_events))
8938 perf_event_bpf_emit_ksymbols(prog, type);
8944 if (!atomic_read(&nr_bpf_events))
8947 bpf_event = (struct perf_bpf_event){
8951 .type = PERF_RECORD_BPF_EVENT,
8952 .size = sizeof(bpf_event.event_id),
8956 .id = prog->aux->id,
8960 BUILD_BUG_ON(BPF_TAG_SIZE % sizeof(u64));
8962 memcpy(bpf_event.event_id.tag, prog->tag, BPF_TAG_SIZE);
8963 perf_iterate_sb(perf_event_bpf_output, &bpf_event, NULL);
8966 struct perf_text_poke_event {
8967 const void *old_bytes;
8968 const void *new_bytes;
8974 struct perf_event_header header;
8980 static int perf_event_text_poke_match(struct perf_event *event)
8982 return event->attr.text_poke;
8985 static void perf_event_text_poke_output(struct perf_event *event, void *data)
8987 struct perf_text_poke_event *text_poke_event = data;
8988 struct perf_output_handle handle;
8989 struct perf_sample_data sample;
8993 if (!perf_event_text_poke_match(event))
8996 perf_event_header__init_id(&text_poke_event->event_id.header, &sample, event);
8998 ret = perf_output_begin(&handle, &sample, event,
8999 text_poke_event->event_id.header.size);
9003 perf_output_put(&handle, text_poke_event->event_id);
9004 perf_output_put(&handle, text_poke_event->old_len);
9005 perf_output_put(&handle, text_poke_event->new_len);
9007 __output_copy(&handle, text_poke_event->old_bytes, text_poke_event->old_len);
9008 __output_copy(&handle, text_poke_event->new_bytes, text_poke_event->new_len);
9010 if (text_poke_event->pad)
9011 __output_copy(&handle, &padding, text_poke_event->pad);
9013 perf_event__output_id_sample(event, &handle, &sample);
9015 perf_output_end(&handle);
9018 void perf_event_text_poke(const void *addr, const void *old_bytes,
9019 size_t old_len, const void *new_bytes, size_t new_len)
9021 struct perf_text_poke_event text_poke_event;
9024 if (!atomic_read(&nr_text_poke_events))
9027 tot = sizeof(text_poke_event.old_len) + old_len;
9028 tot += sizeof(text_poke_event.new_len) + new_len;
9029 pad = ALIGN(tot, sizeof(u64)) - tot;
9031 text_poke_event = (struct perf_text_poke_event){
9032 .old_bytes = old_bytes,
9033 .new_bytes = new_bytes,
9039 .type = PERF_RECORD_TEXT_POKE,
9040 .misc = PERF_RECORD_MISC_KERNEL,
9041 .size = sizeof(text_poke_event.event_id) + tot + pad,
9043 .addr = (unsigned long)addr,
9047 perf_iterate_sb(perf_event_text_poke_output, &text_poke_event, NULL);
9050 void perf_event_itrace_started(struct perf_event *event)
9052 event->attach_state |= PERF_ATTACH_ITRACE;
9055 static void perf_log_itrace_start(struct perf_event *event)
9057 struct perf_output_handle handle;
9058 struct perf_sample_data sample;
9059 struct perf_aux_event {
9060 struct perf_event_header header;
9067 event = event->parent;
9069 if (!(event->pmu->capabilities & PERF_PMU_CAP_ITRACE) ||
9070 event->attach_state & PERF_ATTACH_ITRACE)
9073 rec.header.type = PERF_RECORD_ITRACE_START;
9074 rec.header.misc = 0;
9075 rec.header.size = sizeof(rec);
9076 rec.pid = perf_event_pid(event, current);
9077 rec.tid = perf_event_tid(event, current);
9079 perf_event_header__init_id(&rec.header, &sample, event);
9080 ret = perf_output_begin(&handle, &sample, event, rec.header.size);
9085 perf_output_put(&handle, rec);
9086 perf_event__output_id_sample(event, &handle, &sample);
9088 perf_output_end(&handle);
9091 void perf_report_aux_output_id(struct perf_event *event, u64 hw_id)
9093 struct perf_output_handle handle;
9094 struct perf_sample_data sample;
9095 struct perf_aux_event {
9096 struct perf_event_header header;
9102 event = event->parent;
9104 rec.header.type = PERF_RECORD_AUX_OUTPUT_HW_ID;
9105 rec.header.misc = 0;
9106 rec.header.size = sizeof(rec);
9109 perf_event_header__init_id(&rec.header, &sample, event);
9110 ret = perf_output_begin(&handle, &sample, event, rec.header.size);
9115 perf_output_put(&handle, rec);
9116 perf_event__output_id_sample(event, &handle, &sample);
9118 perf_output_end(&handle);
9122 __perf_event_account_interrupt(struct perf_event *event, int throttle)
9124 struct hw_perf_event *hwc = &event->hw;
9128 seq = __this_cpu_read(perf_throttled_seq);
9129 if (seq != hwc->interrupts_seq) {
9130 hwc->interrupts_seq = seq;
9131 hwc->interrupts = 1;
9134 if (unlikely(throttle
9135 && hwc->interrupts >= max_samples_per_tick)) {
9136 __this_cpu_inc(perf_throttled_count);
9137 tick_dep_set_cpu(smp_processor_id(), TICK_DEP_BIT_PERF_EVENTS);
9138 hwc->interrupts = MAX_INTERRUPTS;
9139 perf_log_throttle(event, 0);
9144 if (event->attr.freq) {
9145 u64 now = perf_clock();
9146 s64 delta = now - hwc->freq_time_stamp;
9148 hwc->freq_time_stamp = now;
9150 if (delta > 0 && delta < 2*TICK_NSEC)
9151 perf_adjust_period(event, delta, hwc->last_period, true);
9157 int perf_event_account_interrupt(struct perf_event *event)
9159 return __perf_event_account_interrupt(event, 1);
9163 * Generic event overflow handling, sampling.
9166 static int __perf_event_overflow(struct perf_event *event,
9167 int throttle, struct perf_sample_data *data,
9168 struct pt_regs *regs)
9170 int events = atomic_read(&event->event_limit);
9174 * Non-sampling counters might still use the PMI to fold short
9175 * hardware counters, ignore those.
9177 if (unlikely(!is_sampling_event(event)))
9180 ret = __perf_event_account_interrupt(event, throttle);
9183 * XXX event_limit might not quite work as expected on inherited
9187 event->pending_kill = POLL_IN;
9188 if (events && atomic_dec_and_test(&event->event_limit)) {
9190 event->pending_kill = POLL_HUP;
9191 event->pending_addr = data->addr;
9193 perf_event_disable_inatomic(event);
9196 READ_ONCE(event->overflow_handler)(event, data, regs);
9198 if (*perf_event_fasync(event) && event->pending_kill) {
9199 event->pending_wakeup = 1;
9200 irq_work_queue(&event->pending);
9206 int perf_event_overflow(struct perf_event *event,
9207 struct perf_sample_data *data,
9208 struct pt_regs *regs)
9210 return __perf_event_overflow(event, 1, data, regs);
9214 * Generic software event infrastructure
9217 struct swevent_htable {
9218 struct swevent_hlist *swevent_hlist;
9219 struct mutex hlist_mutex;
9222 /* Recursion avoidance in each contexts */
9223 int recursion[PERF_NR_CONTEXTS];
9226 static DEFINE_PER_CPU(struct swevent_htable, swevent_htable);
9229 * We directly increment event->count and keep a second value in
9230 * event->hw.period_left to count intervals. This period event
9231 * is kept in the range [-sample_period, 0] so that we can use the
9235 u64 perf_swevent_set_period(struct perf_event *event)
9237 struct hw_perf_event *hwc = &event->hw;
9238 u64 period = hwc->last_period;
9242 hwc->last_period = hwc->sample_period;
9245 old = val = local64_read(&hwc->period_left);
9249 nr = div64_u64(period + val, period);
9250 offset = nr * period;
9252 if (local64_cmpxchg(&hwc->period_left, old, val) != old)
9258 static void perf_swevent_overflow(struct perf_event *event, u64 overflow,
9259 struct perf_sample_data *data,
9260 struct pt_regs *regs)
9262 struct hw_perf_event *hwc = &event->hw;
9266 overflow = perf_swevent_set_period(event);
9268 if (hwc->interrupts == MAX_INTERRUPTS)
9271 for (; overflow; overflow--) {
9272 if (__perf_event_overflow(event, throttle,
9275 * We inhibit the overflow from happening when
9276 * hwc->interrupts == MAX_INTERRUPTS.
9284 static void perf_swevent_event(struct perf_event *event, u64 nr,
9285 struct perf_sample_data *data,
9286 struct pt_regs *regs)
9288 struct hw_perf_event *hwc = &event->hw;
9290 local64_add(nr, &event->count);
9295 if (!is_sampling_event(event))
9298 if ((event->attr.sample_type & PERF_SAMPLE_PERIOD) && !event->attr.freq) {
9300 return perf_swevent_overflow(event, 1, data, regs);
9302 data->period = event->hw.last_period;
9304 if (nr == 1 && hwc->sample_period == 1 && !event->attr.freq)
9305 return perf_swevent_overflow(event, 1, data, regs);
9307 if (local64_add_negative(nr, &hwc->period_left))
9310 perf_swevent_overflow(event, 0, data, regs);
9313 static int perf_exclude_event(struct perf_event *event,
9314 struct pt_regs *regs)
9316 if (event->hw.state & PERF_HES_STOPPED)
9320 if (event->attr.exclude_user && user_mode(regs))
9323 if (event->attr.exclude_kernel && !user_mode(regs))
9330 static int perf_swevent_match(struct perf_event *event,
9331 enum perf_type_id type,
9333 struct perf_sample_data *data,
9334 struct pt_regs *regs)
9336 if (event->attr.type != type)
9339 if (event->attr.config != event_id)
9342 if (perf_exclude_event(event, regs))
9348 static inline u64 swevent_hash(u64 type, u32 event_id)
9350 u64 val = event_id | (type << 32);
9352 return hash_64(val, SWEVENT_HLIST_BITS);
9355 static inline struct hlist_head *
9356 __find_swevent_head(struct swevent_hlist *hlist, u64 type, u32 event_id)
9358 u64 hash = swevent_hash(type, event_id);
9360 return &hlist->heads[hash];
9363 /* For the read side: events when they trigger */
9364 static inline struct hlist_head *
9365 find_swevent_head_rcu(struct swevent_htable *swhash, u64 type, u32 event_id)
9367 struct swevent_hlist *hlist;
9369 hlist = rcu_dereference(swhash->swevent_hlist);
9373 return __find_swevent_head(hlist, type, event_id);
9376 /* For the event head insertion and removal in the hlist */
9377 static inline struct hlist_head *
9378 find_swevent_head(struct swevent_htable *swhash, struct perf_event *event)
9380 struct swevent_hlist *hlist;
9381 u32 event_id = event->attr.config;
9382 u64 type = event->attr.type;
9385 * Event scheduling is always serialized against hlist allocation
9386 * and release. Which makes the protected version suitable here.
9387 * The context lock guarantees that.
9389 hlist = rcu_dereference_protected(swhash->swevent_hlist,
9390 lockdep_is_held(&event->ctx->lock));
9394 return __find_swevent_head(hlist, type, event_id);
9397 static void do_perf_sw_event(enum perf_type_id type, u32 event_id,
9399 struct perf_sample_data *data,
9400 struct pt_regs *regs)
9402 struct swevent_htable *swhash = this_cpu_ptr(&swevent_htable);
9403 struct perf_event *event;
9404 struct hlist_head *head;
9407 head = find_swevent_head_rcu(swhash, type, event_id);
9411 hlist_for_each_entry_rcu(event, head, hlist_entry) {
9412 if (perf_swevent_match(event, type, event_id, data, regs))
9413 perf_swevent_event(event, nr, data, regs);
9419 DEFINE_PER_CPU(struct pt_regs, __perf_regs[4]);
9421 int perf_swevent_get_recursion_context(void)
9423 struct swevent_htable *swhash = this_cpu_ptr(&swevent_htable);
9425 return get_recursion_context(swhash->recursion);
9427 EXPORT_SYMBOL_GPL(perf_swevent_get_recursion_context);
9429 void perf_swevent_put_recursion_context(int rctx)
9431 struct swevent_htable *swhash = this_cpu_ptr(&swevent_htable);
9433 put_recursion_context(swhash->recursion, rctx);
9436 void ___perf_sw_event(u32 event_id, u64 nr, struct pt_regs *regs, u64 addr)
9438 struct perf_sample_data data;
9440 if (WARN_ON_ONCE(!regs))
9443 perf_sample_data_init(&data, addr, 0);
9444 do_perf_sw_event(PERF_TYPE_SOFTWARE, event_id, nr, &data, regs);
9447 void __perf_sw_event(u32 event_id, u64 nr, struct pt_regs *regs, u64 addr)
9451 preempt_disable_notrace();
9452 rctx = perf_swevent_get_recursion_context();
9453 if (unlikely(rctx < 0))
9456 ___perf_sw_event(event_id, nr, regs, addr);
9458 perf_swevent_put_recursion_context(rctx);
9460 preempt_enable_notrace();
9463 static void perf_swevent_read(struct perf_event *event)
9467 static int perf_swevent_add(struct perf_event *event, int flags)
9469 struct swevent_htable *swhash = this_cpu_ptr(&swevent_htable);
9470 struct hw_perf_event *hwc = &event->hw;
9471 struct hlist_head *head;
9473 if (is_sampling_event(event)) {
9474 hwc->last_period = hwc->sample_period;
9475 perf_swevent_set_period(event);
9478 hwc->state = !(flags & PERF_EF_START);
9480 head = find_swevent_head(swhash, event);
9481 if (WARN_ON_ONCE(!head))
9484 hlist_add_head_rcu(&event->hlist_entry, head);
9485 perf_event_update_userpage(event);
9490 static void perf_swevent_del(struct perf_event *event, int flags)
9492 hlist_del_rcu(&event->hlist_entry);
9495 static void perf_swevent_start(struct perf_event *event, int flags)
9497 event->hw.state = 0;
9500 static void perf_swevent_stop(struct perf_event *event, int flags)
9502 event->hw.state = PERF_HES_STOPPED;
9505 /* Deref the hlist from the update side */
9506 static inline struct swevent_hlist *
9507 swevent_hlist_deref(struct swevent_htable *swhash)
9509 return rcu_dereference_protected(swhash->swevent_hlist,
9510 lockdep_is_held(&swhash->hlist_mutex));
9513 static void swevent_hlist_release(struct swevent_htable *swhash)
9515 struct swevent_hlist *hlist = swevent_hlist_deref(swhash);
9520 RCU_INIT_POINTER(swhash->swevent_hlist, NULL);
9521 kfree_rcu(hlist, rcu_head);
9524 static void swevent_hlist_put_cpu(int cpu)
9526 struct swevent_htable *swhash = &per_cpu(swevent_htable, cpu);
9528 mutex_lock(&swhash->hlist_mutex);
9530 if (!--swhash->hlist_refcount)
9531 swevent_hlist_release(swhash);
9533 mutex_unlock(&swhash->hlist_mutex);
9536 static void swevent_hlist_put(void)
9540 for_each_possible_cpu(cpu)
9541 swevent_hlist_put_cpu(cpu);
9544 static int swevent_hlist_get_cpu(int cpu)
9546 struct swevent_htable *swhash = &per_cpu(swevent_htable, cpu);
9549 mutex_lock(&swhash->hlist_mutex);
9550 if (!swevent_hlist_deref(swhash) &&
9551 cpumask_test_cpu(cpu, perf_online_mask)) {
9552 struct swevent_hlist *hlist;
9554 hlist = kzalloc(sizeof(*hlist), GFP_KERNEL);
9559 rcu_assign_pointer(swhash->swevent_hlist, hlist);
9561 swhash->hlist_refcount++;
9563 mutex_unlock(&swhash->hlist_mutex);
9568 static int swevent_hlist_get(void)
9570 int err, cpu, failed_cpu;
9572 mutex_lock(&pmus_lock);
9573 for_each_possible_cpu(cpu) {
9574 err = swevent_hlist_get_cpu(cpu);
9580 mutex_unlock(&pmus_lock);
9583 for_each_possible_cpu(cpu) {
9584 if (cpu == failed_cpu)
9586 swevent_hlist_put_cpu(cpu);
9588 mutex_unlock(&pmus_lock);
9592 struct static_key perf_swevent_enabled[PERF_COUNT_SW_MAX];
9594 static void sw_perf_event_destroy(struct perf_event *event)
9596 u64 event_id = event->attr.config;
9598 WARN_ON(event->parent);
9600 static_key_slow_dec(&perf_swevent_enabled[event_id]);
9601 swevent_hlist_put();
9604 static int perf_swevent_init(struct perf_event *event)
9606 u64 event_id = event->attr.config;
9608 if (event->attr.type != PERF_TYPE_SOFTWARE)
9612 * no branch sampling for software events
9614 if (has_branch_stack(event))
9618 case PERF_COUNT_SW_CPU_CLOCK:
9619 case PERF_COUNT_SW_TASK_CLOCK:
9626 if (event_id >= PERF_COUNT_SW_MAX)
9629 if (!event->parent) {
9632 err = swevent_hlist_get();
9636 static_key_slow_inc(&perf_swevent_enabled[event_id]);
9637 event->destroy = sw_perf_event_destroy;
9643 static struct pmu perf_swevent = {
9644 .task_ctx_nr = perf_sw_context,
9646 .capabilities = PERF_PMU_CAP_NO_NMI,
9648 .event_init = perf_swevent_init,
9649 .add = perf_swevent_add,
9650 .del = perf_swevent_del,
9651 .start = perf_swevent_start,
9652 .stop = perf_swevent_stop,
9653 .read = perf_swevent_read,
9656 #ifdef CONFIG_EVENT_TRACING
9658 static int perf_tp_filter_match(struct perf_event *event,
9659 struct perf_sample_data *data)
9661 void *record = data->raw->frag.data;
9663 /* only top level events have filters set */
9665 event = event->parent;
9667 if (likely(!event->filter) || filter_match_preds(event->filter, record))
9672 static int perf_tp_event_match(struct perf_event *event,
9673 struct perf_sample_data *data,
9674 struct pt_regs *regs)
9676 if (event->hw.state & PERF_HES_STOPPED)
9679 * If exclude_kernel, only trace user-space tracepoints (uprobes)
9681 if (event->attr.exclude_kernel && !user_mode(regs))
9684 if (!perf_tp_filter_match(event, data))
9690 void perf_trace_run_bpf_submit(void *raw_data, int size, int rctx,
9691 struct trace_event_call *call, u64 count,
9692 struct pt_regs *regs, struct hlist_head *head,
9693 struct task_struct *task)
9695 if (bpf_prog_array_valid(call)) {
9696 *(struct pt_regs **)raw_data = regs;
9697 if (!trace_call_bpf(call, raw_data) || hlist_empty(head)) {
9698 perf_swevent_put_recursion_context(rctx);
9702 perf_tp_event(call->event.type, count, raw_data, size, regs, head,
9705 EXPORT_SYMBOL_GPL(perf_trace_run_bpf_submit);
9707 void perf_tp_event(u16 event_type, u64 count, void *record, int entry_size,
9708 struct pt_regs *regs, struct hlist_head *head, int rctx,
9709 struct task_struct *task)
9711 struct perf_sample_data data;
9712 struct perf_event *event;
9714 struct perf_raw_record raw = {
9721 perf_sample_data_init(&data, 0, 0);
9724 perf_trace_buf_update(record, event_type);
9726 hlist_for_each_entry_rcu(event, head, hlist_entry) {
9727 if (perf_tp_event_match(event, &data, regs))
9728 perf_swevent_event(event, count, &data, regs);
9732 * If we got specified a target task, also iterate its context and
9733 * deliver this event there too.
9735 if (task && task != current) {
9736 struct perf_event_context *ctx;
9737 struct trace_entry *entry = record;
9740 ctx = rcu_dereference(task->perf_event_ctxp[perf_sw_context]);
9744 list_for_each_entry_rcu(event, &ctx->event_list, event_entry) {
9745 if (event->cpu != smp_processor_id())
9747 if (event->attr.type != PERF_TYPE_TRACEPOINT)
9749 if (event->attr.config != entry->type)
9751 /* Cannot deliver synchronous signal to other task. */
9752 if (event->attr.sigtrap)
9754 if (perf_tp_event_match(event, &data, regs))
9755 perf_swevent_event(event, count, &data, regs);
9761 perf_swevent_put_recursion_context(rctx);
9763 EXPORT_SYMBOL_GPL(perf_tp_event);
9765 static void tp_perf_event_destroy(struct perf_event *event)
9767 perf_trace_destroy(event);
9770 static int perf_tp_event_init(struct perf_event *event)
9774 if (event->attr.type != PERF_TYPE_TRACEPOINT)
9778 * no branch sampling for tracepoint events
9780 if (has_branch_stack(event))
9783 err = perf_trace_init(event);
9787 event->destroy = tp_perf_event_destroy;
9792 static struct pmu perf_tracepoint = {
9793 .task_ctx_nr = perf_sw_context,
9795 .event_init = perf_tp_event_init,
9796 .add = perf_trace_add,
9797 .del = perf_trace_del,
9798 .start = perf_swevent_start,
9799 .stop = perf_swevent_stop,
9800 .read = perf_swevent_read,
9803 #if defined(CONFIG_KPROBE_EVENTS) || defined(CONFIG_UPROBE_EVENTS)
9805 * Flags in config, used by dynamic PMU kprobe and uprobe
9806 * The flags should match following PMU_FORMAT_ATTR().
9808 * PERF_PROBE_CONFIG_IS_RETPROBE if set, create kretprobe/uretprobe
9809 * if not set, create kprobe/uprobe
9811 * The following values specify a reference counter (or semaphore in the
9812 * terminology of tools like dtrace, systemtap, etc.) Userspace Statically
9813 * Defined Tracepoints (USDT). Currently, we use 40 bit for the offset.
9815 * PERF_UPROBE_REF_CTR_OFFSET_BITS # of bits in config as th offset
9816 * PERF_UPROBE_REF_CTR_OFFSET_SHIFT # of bits to shift left
9818 enum perf_probe_config {
9819 PERF_PROBE_CONFIG_IS_RETPROBE = 1U << 0, /* [k,u]retprobe */
9820 PERF_UPROBE_REF_CTR_OFFSET_BITS = 32,
9821 PERF_UPROBE_REF_CTR_OFFSET_SHIFT = 64 - PERF_UPROBE_REF_CTR_OFFSET_BITS,
9824 PMU_FORMAT_ATTR(retprobe, "config:0");
9827 #ifdef CONFIG_KPROBE_EVENTS
9828 static struct attribute *kprobe_attrs[] = {
9829 &format_attr_retprobe.attr,
9833 static struct attribute_group kprobe_format_group = {
9835 .attrs = kprobe_attrs,
9838 static const struct attribute_group *kprobe_attr_groups[] = {
9839 &kprobe_format_group,
9843 static int perf_kprobe_event_init(struct perf_event *event);
9844 static struct pmu perf_kprobe = {
9845 .task_ctx_nr = perf_sw_context,
9846 .event_init = perf_kprobe_event_init,
9847 .add = perf_trace_add,
9848 .del = perf_trace_del,
9849 .start = perf_swevent_start,
9850 .stop = perf_swevent_stop,
9851 .read = perf_swevent_read,
9852 .attr_groups = kprobe_attr_groups,
9855 static int perf_kprobe_event_init(struct perf_event *event)
9860 if (event->attr.type != perf_kprobe.type)
9863 if (!perfmon_capable())
9867 * no branch sampling for probe events
9869 if (has_branch_stack(event))
9872 is_retprobe = event->attr.config & PERF_PROBE_CONFIG_IS_RETPROBE;
9873 err = perf_kprobe_init(event, is_retprobe);
9877 event->destroy = perf_kprobe_destroy;
9881 #endif /* CONFIG_KPROBE_EVENTS */
9883 #ifdef CONFIG_UPROBE_EVENTS
9884 PMU_FORMAT_ATTR(ref_ctr_offset, "config:32-63");
9886 static struct attribute *uprobe_attrs[] = {
9887 &format_attr_retprobe.attr,
9888 &format_attr_ref_ctr_offset.attr,
9892 static struct attribute_group uprobe_format_group = {
9894 .attrs = uprobe_attrs,
9897 static const struct attribute_group *uprobe_attr_groups[] = {
9898 &uprobe_format_group,
9902 static int perf_uprobe_event_init(struct perf_event *event);
9903 static struct pmu perf_uprobe = {
9904 .task_ctx_nr = perf_sw_context,
9905 .event_init = perf_uprobe_event_init,
9906 .add = perf_trace_add,
9907 .del = perf_trace_del,
9908 .start = perf_swevent_start,
9909 .stop = perf_swevent_stop,
9910 .read = perf_swevent_read,
9911 .attr_groups = uprobe_attr_groups,
9914 static int perf_uprobe_event_init(struct perf_event *event)
9917 unsigned long ref_ctr_offset;
9920 if (event->attr.type != perf_uprobe.type)
9923 if (!perfmon_capable())
9927 * no branch sampling for probe events
9929 if (has_branch_stack(event))
9932 is_retprobe = event->attr.config & PERF_PROBE_CONFIG_IS_RETPROBE;
9933 ref_ctr_offset = event->attr.config >> PERF_UPROBE_REF_CTR_OFFSET_SHIFT;
9934 err = perf_uprobe_init(event, ref_ctr_offset, is_retprobe);
9938 event->destroy = perf_uprobe_destroy;
9942 #endif /* CONFIG_UPROBE_EVENTS */
9944 static inline void perf_tp_register(void)
9946 perf_pmu_register(&perf_tracepoint, "tracepoint", PERF_TYPE_TRACEPOINT);
9947 #ifdef CONFIG_KPROBE_EVENTS
9948 perf_pmu_register(&perf_kprobe, "kprobe", -1);
9950 #ifdef CONFIG_UPROBE_EVENTS
9951 perf_pmu_register(&perf_uprobe, "uprobe", -1);
9955 static void perf_event_free_filter(struct perf_event *event)
9957 ftrace_profile_free_filter(event);
9960 #ifdef CONFIG_BPF_SYSCALL
9961 static void bpf_overflow_handler(struct perf_event *event,
9962 struct perf_sample_data *data,
9963 struct pt_regs *regs)
9965 struct bpf_perf_event_data_kern ctx = {
9969 struct bpf_prog *prog;
9972 ctx.regs = perf_arch_bpf_user_pt_regs(regs);
9973 if (unlikely(__this_cpu_inc_return(bpf_prog_active) != 1))
9976 prog = READ_ONCE(event->prog);
9978 ret = bpf_prog_run(prog, &ctx);
9981 __this_cpu_dec(bpf_prog_active);
9985 event->orig_overflow_handler(event, data, regs);
9988 static int perf_event_set_bpf_handler(struct perf_event *event,
9989 struct bpf_prog *prog,
9992 if (event->overflow_handler_context)
9993 /* hw breakpoint or kernel counter */
9999 if (prog->type != BPF_PROG_TYPE_PERF_EVENT)
10002 if (event->attr.precise_ip &&
10003 prog->call_get_stack &&
10004 (!(event->attr.sample_type & __PERF_SAMPLE_CALLCHAIN_EARLY) ||
10005 event->attr.exclude_callchain_kernel ||
10006 event->attr.exclude_callchain_user)) {
10008 * On perf_event with precise_ip, calling bpf_get_stack()
10009 * may trigger unwinder warnings and occasional crashes.
10010 * bpf_get_[stack|stackid] works around this issue by using
10011 * callchain attached to perf_sample_data. If the
10012 * perf_event does not full (kernel and user) callchain
10013 * attached to perf_sample_data, do not allow attaching BPF
10014 * program that calls bpf_get_[stack|stackid].
10019 event->prog = prog;
10020 event->bpf_cookie = bpf_cookie;
10021 event->orig_overflow_handler = READ_ONCE(event->overflow_handler);
10022 WRITE_ONCE(event->overflow_handler, bpf_overflow_handler);
10026 static void perf_event_free_bpf_handler(struct perf_event *event)
10028 struct bpf_prog *prog = event->prog;
10033 WRITE_ONCE(event->overflow_handler, event->orig_overflow_handler);
10034 event->prog = NULL;
10035 bpf_prog_put(prog);
10038 static int perf_event_set_bpf_handler(struct perf_event *event,
10039 struct bpf_prog *prog,
10042 return -EOPNOTSUPP;
10044 static void perf_event_free_bpf_handler(struct perf_event *event)
10050 * returns true if the event is a tracepoint, or a kprobe/upprobe created
10051 * with perf_event_open()
10053 static inline bool perf_event_is_tracing(struct perf_event *event)
10055 if (event->pmu == &perf_tracepoint)
10057 #ifdef CONFIG_KPROBE_EVENTS
10058 if (event->pmu == &perf_kprobe)
10061 #ifdef CONFIG_UPROBE_EVENTS
10062 if (event->pmu == &perf_uprobe)
10068 int perf_event_set_bpf_prog(struct perf_event *event, struct bpf_prog *prog,
10071 bool is_kprobe, is_tracepoint, is_syscall_tp;
10073 if (!perf_event_is_tracing(event))
10074 return perf_event_set_bpf_handler(event, prog, bpf_cookie);
10076 is_kprobe = event->tp_event->flags & TRACE_EVENT_FL_UKPROBE;
10077 is_tracepoint = event->tp_event->flags & TRACE_EVENT_FL_TRACEPOINT;
10078 is_syscall_tp = is_syscall_trace_event(event->tp_event);
10079 if (!is_kprobe && !is_tracepoint && !is_syscall_tp)
10080 /* bpf programs can only be attached to u/kprobe or tracepoint */
10083 if ((is_kprobe && prog->type != BPF_PROG_TYPE_KPROBE) ||
10084 (is_tracepoint && prog->type != BPF_PROG_TYPE_TRACEPOINT) ||
10085 (is_syscall_tp && prog->type != BPF_PROG_TYPE_TRACEPOINT))
10088 /* Kprobe override only works for kprobes, not uprobes. */
10089 if (prog->kprobe_override &&
10090 !(event->tp_event->flags & TRACE_EVENT_FL_KPROBE))
10093 if (is_tracepoint || is_syscall_tp) {
10094 int off = trace_event_get_offsets(event->tp_event);
10096 if (prog->aux->max_ctx_offset > off)
10100 return perf_event_attach_bpf_prog(event, prog, bpf_cookie);
10103 void perf_event_free_bpf_prog(struct perf_event *event)
10105 if (!perf_event_is_tracing(event)) {
10106 perf_event_free_bpf_handler(event);
10109 perf_event_detach_bpf_prog(event);
10114 static inline void perf_tp_register(void)
10118 static void perf_event_free_filter(struct perf_event *event)
10122 int perf_event_set_bpf_prog(struct perf_event *event, struct bpf_prog *prog,
10128 void perf_event_free_bpf_prog(struct perf_event *event)
10131 #endif /* CONFIG_EVENT_TRACING */
10133 #ifdef CONFIG_HAVE_HW_BREAKPOINT
10134 void perf_bp_event(struct perf_event *bp, void *data)
10136 struct perf_sample_data sample;
10137 struct pt_regs *regs = data;
10139 perf_sample_data_init(&sample, bp->attr.bp_addr, 0);
10141 if (!bp->hw.state && !perf_exclude_event(bp, regs))
10142 perf_swevent_event(bp, 1, &sample, regs);
10147 * Allocate a new address filter
10149 static struct perf_addr_filter *
10150 perf_addr_filter_new(struct perf_event *event, struct list_head *filters)
10152 int node = cpu_to_node(event->cpu == -1 ? 0 : event->cpu);
10153 struct perf_addr_filter *filter;
10155 filter = kzalloc_node(sizeof(*filter), GFP_KERNEL, node);
10159 INIT_LIST_HEAD(&filter->entry);
10160 list_add_tail(&filter->entry, filters);
10165 static void free_filters_list(struct list_head *filters)
10167 struct perf_addr_filter *filter, *iter;
10169 list_for_each_entry_safe(filter, iter, filters, entry) {
10170 path_put(&filter->path);
10171 list_del(&filter->entry);
10177 * Free existing address filters and optionally install new ones
10179 static void perf_addr_filters_splice(struct perf_event *event,
10180 struct list_head *head)
10182 unsigned long flags;
10185 if (!has_addr_filter(event))
10188 /* don't bother with children, they don't have their own filters */
10192 raw_spin_lock_irqsave(&event->addr_filters.lock, flags);
10194 list_splice_init(&event->addr_filters.list, &list);
10196 list_splice(head, &event->addr_filters.list);
10198 raw_spin_unlock_irqrestore(&event->addr_filters.lock, flags);
10200 free_filters_list(&list);
10204 * Scan through mm's vmas and see if one of them matches the
10205 * @filter; if so, adjust filter's address range.
10206 * Called with mm::mmap_lock down for reading.
10208 static void perf_addr_filter_apply(struct perf_addr_filter *filter,
10209 struct mm_struct *mm,
10210 struct perf_addr_filter_range *fr)
10212 struct vm_area_struct *vma;
10214 for (vma = mm->mmap; vma; vma = vma->vm_next) {
10218 if (perf_addr_filter_vma_adjust(filter, vma, fr))
10224 * Update event's address range filters based on the
10225 * task's existing mappings, if any.
10227 static void perf_event_addr_filters_apply(struct perf_event *event)
10229 struct perf_addr_filters_head *ifh = perf_event_addr_filters(event);
10230 struct task_struct *task = READ_ONCE(event->ctx->task);
10231 struct perf_addr_filter *filter;
10232 struct mm_struct *mm = NULL;
10233 unsigned int count = 0;
10234 unsigned long flags;
10237 * We may observe TASK_TOMBSTONE, which means that the event tear-down
10238 * will stop on the parent's child_mutex that our caller is also holding
10240 if (task == TASK_TOMBSTONE)
10243 if (ifh->nr_file_filters) {
10244 mm = get_task_mm(task);
10248 mmap_read_lock(mm);
10251 raw_spin_lock_irqsave(&ifh->lock, flags);
10252 list_for_each_entry(filter, &ifh->list, entry) {
10253 if (filter->path.dentry) {
10255 * Adjust base offset if the filter is associated to a
10256 * binary that needs to be mapped:
10258 event->addr_filter_ranges[count].start = 0;
10259 event->addr_filter_ranges[count].size = 0;
10261 perf_addr_filter_apply(filter, mm, &event->addr_filter_ranges[count]);
10263 event->addr_filter_ranges[count].start = filter->offset;
10264 event->addr_filter_ranges[count].size = filter->size;
10270 event->addr_filters_gen++;
10271 raw_spin_unlock_irqrestore(&ifh->lock, flags);
10273 if (ifh->nr_file_filters) {
10274 mmap_read_unlock(mm);
10280 perf_event_stop(event, 1);
10284 * Address range filtering: limiting the data to certain
10285 * instruction address ranges. Filters are ioctl()ed to us from
10286 * userspace as ascii strings.
10288 * Filter string format:
10290 * ACTION RANGE_SPEC
10291 * where ACTION is one of the
10292 * * "filter": limit the trace to this region
10293 * * "start": start tracing from this address
10294 * * "stop": stop tracing at this address/region;
10296 * * for kernel addresses: <start address>[/<size>]
10297 * * for object files: <start address>[/<size>]@</path/to/object/file>
10299 * if <size> is not specified or is zero, the range is treated as a single
10300 * address; not valid for ACTION=="filter".
10314 IF_STATE_ACTION = 0,
10319 static const match_table_t if_tokens = {
10320 { IF_ACT_FILTER, "filter" },
10321 { IF_ACT_START, "start" },
10322 { IF_ACT_STOP, "stop" },
10323 { IF_SRC_FILE, "%u/%u@%s" },
10324 { IF_SRC_KERNEL, "%u/%u" },
10325 { IF_SRC_FILEADDR, "%u@%s" },
10326 { IF_SRC_KERNELADDR, "%u" },
10327 { IF_ACT_NONE, NULL },
10331 * Address filter string parser
10334 perf_event_parse_addr_filter(struct perf_event *event, char *fstr,
10335 struct list_head *filters)
10337 struct perf_addr_filter *filter = NULL;
10338 char *start, *orig, *filename = NULL;
10339 substring_t args[MAX_OPT_ARGS];
10340 int state = IF_STATE_ACTION, token;
10341 unsigned int kernel = 0;
10344 orig = fstr = kstrdup(fstr, GFP_KERNEL);
10348 while ((start = strsep(&fstr, " ,\n")) != NULL) {
10349 static const enum perf_addr_filter_action_t actions[] = {
10350 [IF_ACT_FILTER] = PERF_ADDR_FILTER_ACTION_FILTER,
10351 [IF_ACT_START] = PERF_ADDR_FILTER_ACTION_START,
10352 [IF_ACT_STOP] = PERF_ADDR_FILTER_ACTION_STOP,
10359 /* filter definition begins */
10360 if (state == IF_STATE_ACTION) {
10361 filter = perf_addr_filter_new(event, filters);
10366 token = match_token(start, if_tokens, args);
10368 case IF_ACT_FILTER:
10371 if (state != IF_STATE_ACTION)
10374 filter->action = actions[token];
10375 state = IF_STATE_SOURCE;
10378 case IF_SRC_KERNELADDR:
10379 case IF_SRC_KERNEL:
10383 case IF_SRC_FILEADDR:
10385 if (state != IF_STATE_SOURCE)
10389 ret = kstrtoul(args[0].from, 0, &filter->offset);
10393 if (token == IF_SRC_KERNEL || token == IF_SRC_FILE) {
10395 ret = kstrtoul(args[1].from, 0, &filter->size);
10400 if (token == IF_SRC_FILE || token == IF_SRC_FILEADDR) {
10401 int fpos = token == IF_SRC_FILE ? 2 : 1;
10404 filename = match_strdup(&args[fpos]);
10411 state = IF_STATE_END;
10419 * Filter definition is fully parsed, validate and install it.
10420 * Make sure that it doesn't contradict itself or the event's
10423 if (state == IF_STATE_END) {
10427 * ACTION "filter" must have a non-zero length region
10430 if (filter->action == PERF_ADDR_FILTER_ACTION_FILTER &&
10439 * For now, we only support file-based filters
10440 * in per-task events; doing so for CPU-wide
10441 * events requires additional context switching
10442 * trickery, since same object code will be
10443 * mapped at different virtual addresses in
10444 * different processes.
10447 if (!event->ctx->task)
10450 /* look up the path and grab its inode */
10451 ret = kern_path(filename, LOOKUP_FOLLOW,
10457 if (!filter->path.dentry ||
10458 !S_ISREG(d_inode(filter->path.dentry)
10462 event->addr_filters.nr_file_filters++;
10465 /* ready to consume more filters */
10468 state = IF_STATE_ACTION;
10474 if (state != IF_STATE_ACTION)
10484 free_filters_list(filters);
10491 perf_event_set_addr_filter(struct perf_event *event, char *filter_str)
10493 LIST_HEAD(filters);
10497 * Since this is called in perf_ioctl() path, we're already holding
10500 lockdep_assert_held(&event->ctx->mutex);
10502 if (WARN_ON_ONCE(event->parent))
10505 ret = perf_event_parse_addr_filter(event, filter_str, &filters);
10507 goto fail_clear_files;
10509 ret = event->pmu->addr_filters_validate(&filters);
10511 goto fail_free_filters;
10513 /* remove existing filters, if any */
10514 perf_addr_filters_splice(event, &filters);
10516 /* install new filters */
10517 perf_event_for_each_child(event, perf_event_addr_filters_apply);
10522 free_filters_list(&filters);
10525 event->addr_filters.nr_file_filters = 0;
10530 static int perf_event_set_filter(struct perf_event *event, void __user *arg)
10535 filter_str = strndup_user(arg, PAGE_SIZE);
10536 if (IS_ERR(filter_str))
10537 return PTR_ERR(filter_str);
10539 #ifdef CONFIG_EVENT_TRACING
10540 if (perf_event_is_tracing(event)) {
10541 struct perf_event_context *ctx = event->ctx;
10544 * Beware, here be dragons!!
10546 * the tracepoint muck will deadlock against ctx->mutex, but
10547 * the tracepoint stuff does not actually need it. So
10548 * temporarily drop ctx->mutex. As per perf_event_ctx_lock() we
10549 * already have a reference on ctx.
10551 * This can result in event getting moved to a different ctx,
10552 * but that does not affect the tracepoint state.
10554 mutex_unlock(&ctx->mutex);
10555 ret = ftrace_profile_set_filter(event, event->attr.config, filter_str);
10556 mutex_lock(&ctx->mutex);
10559 if (has_addr_filter(event))
10560 ret = perf_event_set_addr_filter(event, filter_str);
10567 * hrtimer based swevent callback
10570 static enum hrtimer_restart perf_swevent_hrtimer(struct hrtimer *hrtimer)
10572 enum hrtimer_restart ret = HRTIMER_RESTART;
10573 struct perf_sample_data data;
10574 struct pt_regs *regs;
10575 struct perf_event *event;
10578 event = container_of(hrtimer, struct perf_event, hw.hrtimer);
10580 if (event->state != PERF_EVENT_STATE_ACTIVE)
10581 return HRTIMER_NORESTART;
10583 event->pmu->read(event);
10585 perf_sample_data_init(&data, 0, event->hw.last_period);
10586 regs = get_irq_regs();
10588 if (regs && !perf_exclude_event(event, regs)) {
10589 if (!(event->attr.exclude_idle && is_idle_task(current)))
10590 if (__perf_event_overflow(event, 1, &data, regs))
10591 ret = HRTIMER_NORESTART;
10594 period = max_t(u64, 10000, event->hw.sample_period);
10595 hrtimer_forward_now(hrtimer, ns_to_ktime(period));
10600 static void perf_swevent_start_hrtimer(struct perf_event *event)
10602 struct hw_perf_event *hwc = &event->hw;
10605 if (!is_sampling_event(event))
10608 period = local64_read(&hwc->period_left);
10613 local64_set(&hwc->period_left, 0);
10615 period = max_t(u64, 10000, hwc->sample_period);
10617 hrtimer_start(&hwc->hrtimer, ns_to_ktime(period),
10618 HRTIMER_MODE_REL_PINNED_HARD);
10621 static void perf_swevent_cancel_hrtimer(struct perf_event *event)
10623 struct hw_perf_event *hwc = &event->hw;
10625 if (is_sampling_event(event)) {
10626 ktime_t remaining = hrtimer_get_remaining(&hwc->hrtimer);
10627 local64_set(&hwc->period_left, ktime_to_ns(remaining));
10629 hrtimer_cancel(&hwc->hrtimer);
10633 static void perf_swevent_init_hrtimer(struct perf_event *event)
10635 struct hw_perf_event *hwc = &event->hw;
10637 if (!is_sampling_event(event))
10640 hrtimer_init(&hwc->hrtimer, CLOCK_MONOTONIC, HRTIMER_MODE_REL_HARD);
10641 hwc->hrtimer.function = perf_swevent_hrtimer;
10644 * Since hrtimers have a fixed rate, we can do a static freq->period
10645 * mapping and avoid the whole period adjust feedback stuff.
10647 if (event->attr.freq) {
10648 long freq = event->attr.sample_freq;
10650 event->attr.sample_period = NSEC_PER_SEC / freq;
10651 hwc->sample_period = event->attr.sample_period;
10652 local64_set(&hwc->period_left, hwc->sample_period);
10653 hwc->last_period = hwc->sample_period;
10654 event->attr.freq = 0;
10659 * Software event: cpu wall time clock
10662 static void cpu_clock_event_update(struct perf_event *event)
10667 now = local_clock();
10668 prev = local64_xchg(&event->hw.prev_count, now);
10669 local64_add(now - prev, &event->count);
10672 static void cpu_clock_event_start(struct perf_event *event, int flags)
10674 local64_set(&event->hw.prev_count, local_clock());
10675 perf_swevent_start_hrtimer(event);
10678 static void cpu_clock_event_stop(struct perf_event *event, int flags)
10680 perf_swevent_cancel_hrtimer(event);
10681 cpu_clock_event_update(event);
10684 static int cpu_clock_event_add(struct perf_event *event, int flags)
10686 if (flags & PERF_EF_START)
10687 cpu_clock_event_start(event, flags);
10688 perf_event_update_userpage(event);
10693 static void cpu_clock_event_del(struct perf_event *event, int flags)
10695 cpu_clock_event_stop(event, flags);
10698 static void cpu_clock_event_read(struct perf_event *event)
10700 cpu_clock_event_update(event);
10703 static int cpu_clock_event_init(struct perf_event *event)
10705 if (event->attr.type != PERF_TYPE_SOFTWARE)
10708 if (event->attr.config != PERF_COUNT_SW_CPU_CLOCK)
10712 * no branch sampling for software events
10714 if (has_branch_stack(event))
10715 return -EOPNOTSUPP;
10717 perf_swevent_init_hrtimer(event);
10722 static struct pmu perf_cpu_clock = {
10723 .task_ctx_nr = perf_sw_context,
10725 .capabilities = PERF_PMU_CAP_NO_NMI,
10727 .event_init = cpu_clock_event_init,
10728 .add = cpu_clock_event_add,
10729 .del = cpu_clock_event_del,
10730 .start = cpu_clock_event_start,
10731 .stop = cpu_clock_event_stop,
10732 .read = cpu_clock_event_read,
10736 * Software event: task time clock
10739 static void task_clock_event_update(struct perf_event *event, u64 now)
10744 prev = local64_xchg(&event->hw.prev_count, now);
10745 delta = now - prev;
10746 local64_add(delta, &event->count);
10749 static void task_clock_event_start(struct perf_event *event, int flags)
10751 local64_set(&event->hw.prev_count, event->ctx->time);
10752 perf_swevent_start_hrtimer(event);
10755 static void task_clock_event_stop(struct perf_event *event, int flags)
10757 perf_swevent_cancel_hrtimer(event);
10758 task_clock_event_update(event, event->ctx->time);
10761 static int task_clock_event_add(struct perf_event *event, int flags)
10763 if (flags & PERF_EF_START)
10764 task_clock_event_start(event, flags);
10765 perf_event_update_userpage(event);
10770 static void task_clock_event_del(struct perf_event *event, int flags)
10772 task_clock_event_stop(event, PERF_EF_UPDATE);
10775 static void task_clock_event_read(struct perf_event *event)
10777 u64 now = perf_clock();
10778 u64 delta = now - event->ctx->timestamp;
10779 u64 time = event->ctx->time + delta;
10781 task_clock_event_update(event, time);
10784 static int task_clock_event_init(struct perf_event *event)
10786 if (event->attr.type != PERF_TYPE_SOFTWARE)
10789 if (event->attr.config != PERF_COUNT_SW_TASK_CLOCK)
10793 * no branch sampling for software events
10795 if (has_branch_stack(event))
10796 return -EOPNOTSUPP;
10798 perf_swevent_init_hrtimer(event);
10803 static struct pmu perf_task_clock = {
10804 .task_ctx_nr = perf_sw_context,
10806 .capabilities = PERF_PMU_CAP_NO_NMI,
10808 .event_init = task_clock_event_init,
10809 .add = task_clock_event_add,
10810 .del = task_clock_event_del,
10811 .start = task_clock_event_start,
10812 .stop = task_clock_event_stop,
10813 .read = task_clock_event_read,
10816 static void perf_pmu_nop_void(struct pmu *pmu)
10820 static void perf_pmu_nop_txn(struct pmu *pmu, unsigned int flags)
10824 static int perf_pmu_nop_int(struct pmu *pmu)
10829 static int perf_event_nop_int(struct perf_event *event, u64 value)
10834 static DEFINE_PER_CPU(unsigned int, nop_txn_flags);
10836 static void perf_pmu_start_txn(struct pmu *pmu, unsigned int flags)
10838 __this_cpu_write(nop_txn_flags, flags);
10840 if (flags & ~PERF_PMU_TXN_ADD)
10843 perf_pmu_disable(pmu);
10846 static int perf_pmu_commit_txn(struct pmu *pmu)
10848 unsigned int flags = __this_cpu_read(nop_txn_flags);
10850 __this_cpu_write(nop_txn_flags, 0);
10852 if (flags & ~PERF_PMU_TXN_ADD)
10855 perf_pmu_enable(pmu);
10859 static void perf_pmu_cancel_txn(struct pmu *pmu)
10861 unsigned int flags = __this_cpu_read(nop_txn_flags);
10863 __this_cpu_write(nop_txn_flags, 0);
10865 if (flags & ~PERF_PMU_TXN_ADD)
10868 perf_pmu_enable(pmu);
10871 static int perf_event_idx_default(struct perf_event *event)
10877 * Ensures all contexts with the same task_ctx_nr have the same
10878 * pmu_cpu_context too.
10880 static struct perf_cpu_context __percpu *find_pmu_context(int ctxn)
10887 list_for_each_entry(pmu, &pmus, entry) {
10888 if (pmu->task_ctx_nr == ctxn)
10889 return pmu->pmu_cpu_context;
10895 static void free_pmu_context(struct pmu *pmu)
10898 * Static contexts such as perf_sw_context have a global lifetime
10899 * and may be shared between different PMUs. Avoid freeing them
10900 * when a single PMU is going away.
10902 if (pmu->task_ctx_nr > perf_invalid_context)
10905 free_percpu(pmu->pmu_cpu_context);
10909 * Let userspace know that this PMU supports address range filtering:
10911 static ssize_t nr_addr_filters_show(struct device *dev,
10912 struct device_attribute *attr,
10915 struct pmu *pmu = dev_get_drvdata(dev);
10917 return snprintf(page, PAGE_SIZE - 1, "%d\n", pmu->nr_addr_filters);
10919 DEVICE_ATTR_RO(nr_addr_filters);
10921 static struct idr pmu_idr;
10924 type_show(struct device *dev, struct device_attribute *attr, char *page)
10926 struct pmu *pmu = dev_get_drvdata(dev);
10928 return snprintf(page, PAGE_SIZE-1, "%d\n", pmu->type);
10930 static DEVICE_ATTR_RO(type);
10933 perf_event_mux_interval_ms_show(struct device *dev,
10934 struct device_attribute *attr,
10937 struct pmu *pmu = dev_get_drvdata(dev);
10939 return snprintf(page, PAGE_SIZE-1, "%d\n", pmu->hrtimer_interval_ms);
10942 static DEFINE_MUTEX(mux_interval_mutex);
10945 perf_event_mux_interval_ms_store(struct device *dev,
10946 struct device_attribute *attr,
10947 const char *buf, size_t count)
10949 struct pmu *pmu = dev_get_drvdata(dev);
10950 int timer, cpu, ret;
10952 ret = kstrtoint(buf, 0, &timer);
10959 /* same value, noting to do */
10960 if (timer == pmu->hrtimer_interval_ms)
10963 mutex_lock(&mux_interval_mutex);
10964 pmu->hrtimer_interval_ms = timer;
10966 /* update all cpuctx for this PMU */
10968 for_each_online_cpu(cpu) {
10969 struct perf_cpu_context *cpuctx;
10970 cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
10971 cpuctx->hrtimer_interval = ns_to_ktime(NSEC_PER_MSEC * timer);
10973 cpu_function_call(cpu,
10974 (remote_function_f)perf_mux_hrtimer_restart, cpuctx);
10976 cpus_read_unlock();
10977 mutex_unlock(&mux_interval_mutex);
10981 static DEVICE_ATTR_RW(perf_event_mux_interval_ms);
10983 static struct attribute *pmu_dev_attrs[] = {
10984 &dev_attr_type.attr,
10985 &dev_attr_perf_event_mux_interval_ms.attr,
10988 ATTRIBUTE_GROUPS(pmu_dev);
10990 static int pmu_bus_running;
10991 static struct bus_type pmu_bus = {
10992 .name = "event_source",
10993 .dev_groups = pmu_dev_groups,
10996 static void pmu_dev_release(struct device *dev)
11001 static int pmu_dev_alloc(struct pmu *pmu)
11005 pmu->dev = kzalloc(sizeof(struct device), GFP_KERNEL);
11009 pmu->dev->groups = pmu->attr_groups;
11010 device_initialize(pmu->dev);
11011 ret = dev_set_name(pmu->dev, "%s", pmu->name);
11015 dev_set_drvdata(pmu->dev, pmu);
11016 pmu->dev->bus = &pmu_bus;
11017 pmu->dev->release = pmu_dev_release;
11018 ret = device_add(pmu->dev);
11022 /* For PMUs with address filters, throw in an extra attribute: */
11023 if (pmu->nr_addr_filters)
11024 ret = device_create_file(pmu->dev, &dev_attr_nr_addr_filters);
11029 if (pmu->attr_update)
11030 ret = sysfs_update_groups(&pmu->dev->kobj, pmu->attr_update);
11039 device_del(pmu->dev);
11042 put_device(pmu->dev);
11046 static struct lock_class_key cpuctx_mutex;
11047 static struct lock_class_key cpuctx_lock;
11049 int perf_pmu_register(struct pmu *pmu, const char *name, int type)
11051 int cpu, ret, max = PERF_TYPE_MAX;
11053 mutex_lock(&pmus_lock);
11055 pmu->pmu_disable_count = alloc_percpu(int);
11056 if (!pmu->pmu_disable_count)
11064 if (type != PERF_TYPE_SOFTWARE) {
11068 ret = idr_alloc(&pmu_idr, pmu, max, 0, GFP_KERNEL);
11072 WARN_ON(type >= 0 && ret != type);
11078 if (pmu_bus_running) {
11079 ret = pmu_dev_alloc(pmu);
11085 if (pmu->task_ctx_nr == perf_hw_context) {
11086 static int hw_context_taken = 0;
11089 * Other than systems with heterogeneous CPUs, it never makes
11090 * sense for two PMUs to share perf_hw_context. PMUs which are
11091 * uncore must use perf_invalid_context.
11093 if (WARN_ON_ONCE(hw_context_taken &&
11094 !(pmu->capabilities & PERF_PMU_CAP_HETEROGENEOUS_CPUS)))
11095 pmu->task_ctx_nr = perf_invalid_context;
11097 hw_context_taken = 1;
11100 pmu->pmu_cpu_context = find_pmu_context(pmu->task_ctx_nr);
11101 if (pmu->pmu_cpu_context)
11102 goto got_cpu_context;
11105 pmu->pmu_cpu_context = alloc_percpu(struct perf_cpu_context);
11106 if (!pmu->pmu_cpu_context)
11109 for_each_possible_cpu(cpu) {
11110 struct perf_cpu_context *cpuctx;
11112 cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
11113 __perf_event_init_context(&cpuctx->ctx);
11114 lockdep_set_class(&cpuctx->ctx.mutex, &cpuctx_mutex);
11115 lockdep_set_class(&cpuctx->ctx.lock, &cpuctx_lock);
11116 cpuctx->ctx.pmu = pmu;
11117 cpuctx->online = cpumask_test_cpu(cpu, perf_online_mask);
11119 __perf_mux_hrtimer_init(cpuctx, cpu);
11121 cpuctx->heap_size = ARRAY_SIZE(cpuctx->heap_default);
11122 cpuctx->heap = cpuctx->heap_default;
11126 if (!pmu->start_txn) {
11127 if (pmu->pmu_enable) {
11129 * If we have pmu_enable/pmu_disable calls, install
11130 * transaction stubs that use that to try and batch
11131 * hardware accesses.
11133 pmu->start_txn = perf_pmu_start_txn;
11134 pmu->commit_txn = perf_pmu_commit_txn;
11135 pmu->cancel_txn = perf_pmu_cancel_txn;
11137 pmu->start_txn = perf_pmu_nop_txn;
11138 pmu->commit_txn = perf_pmu_nop_int;
11139 pmu->cancel_txn = perf_pmu_nop_void;
11143 if (!pmu->pmu_enable) {
11144 pmu->pmu_enable = perf_pmu_nop_void;
11145 pmu->pmu_disable = perf_pmu_nop_void;
11148 if (!pmu->check_period)
11149 pmu->check_period = perf_event_nop_int;
11151 if (!pmu->event_idx)
11152 pmu->event_idx = perf_event_idx_default;
11155 * Ensure the TYPE_SOFTWARE PMUs are at the head of the list,
11156 * since these cannot be in the IDR. This way the linear search
11157 * is fast, provided a valid software event is provided.
11159 if (type == PERF_TYPE_SOFTWARE || !name)
11160 list_add_rcu(&pmu->entry, &pmus);
11162 list_add_tail_rcu(&pmu->entry, &pmus);
11164 atomic_set(&pmu->exclusive_cnt, 0);
11167 mutex_unlock(&pmus_lock);
11172 device_del(pmu->dev);
11173 put_device(pmu->dev);
11176 if (pmu->type != PERF_TYPE_SOFTWARE)
11177 idr_remove(&pmu_idr, pmu->type);
11180 free_percpu(pmu->pmu_disable_count);
11183 EXPORT_SYMBOL_GPL(perf_pmu_register);
11185 void perf_pmu_unregister(struct pmu *pmu)
11187 mutex_lock(&pmus_lock);
11188 list_del_rcu(&pmu->entry);
11191 * We dereference the pmu list under both SRCU and regular RCU, so
11192 * synchronize against both of those.
11194 synchronize_srcu(&pmus_srcu);
11197 free_percpu(pmu->pmu_disable_count);
11198 if (pmu->type != PERF_TYPE_SOFTWARE)
11199 idr_remove(&pmu_idr, pmu->type);
11200 if (pmu_bus_running) {
11201 if (pmu->nr_addr_filters)
11202 device_remove_file(pmu->dev, &dev_attr_nr_addr_filters);
11203 device_del(pmu->dev);
11204 put_device(pmu->dev);
11206 free_pmu_context(pmu);
11207 mutex_unlock(&pmus_lock);
11209 EXPORT_SYMBOL_GPL(perf_pmu_unregister);
11211 static inline bool has_extended_regs(struct perf_event *event)
11213 return (event->attr.sample_regs_user & PERF_REG_EXTENDED_MASK) ||
11214 (event->attr.sample_regs_intr & PERF_REG_EXTENDED_MASK);
11217 static int perf_try_init_event(struct pmu *pmu, struct perf_event *event)
11219 struct perf_event_context *ctx = NULL;
11222 if (!try_module_get(pmu->module))
11226 * A number of pmu->event_init() methods iterate the sibling_list to,
11227 * for example, validate if the group fits on the PMU. Therefore,
11228 * if this is a sibling event, acquire the ctx->mutex to protect
11229 * the sibling_list.
11231 if (event->group_leader != event && pmu->task_ctx_nr != perf_sw_context) {
11233 * This ctx->mutex can nest when we're called through
11234 * inheritance. See the perf_event_ctx_lock_nested() comment.
11236 ctx = perf_event_ctx_lock_nested(event->group_leader,
11237 SINGLE_DEPTH_NESTING);
11242 ret = pmu->event_init(event);
11245 perf_event_ctx_unlock(event->group_leader, ctx);
11248 if (!(pmu->capabilities & PERF_PMU_CAP_EXTENDED_REGS) &&
11249 has_extended_regs(event))
11252 if (pmu->capabilities & PERF_PMU_CAP_NO_EXCLUDE &&
11253 event_has_any_exclude_flag(event))
11256 if (ret && event->destroy)
11257 event->destroy(event);
11261 module_put(pmu->module);
11266 static struct pmu *perf_init_event(struct perf_event *event)
11268 bool extended_type = false;
11269 int idx, type, ret;
11272 idx = srcu_read_lock(&pmus_srcu);
11274 /* Try parent's PMU first: */
11275 if (event->parent && event->parent->pmu) {
11276 pmu = event->parent->pmu;
11277 ret = perf_try_init_event(pmu, event);
11283 * PERF_TYPE_HARDWARE and PERF_TYPE_HW_CACHE
11284 * are often aliases for PERF_TYPE_RAW.
11286 type = event->attr.type;
11287 if (type == PERF_TYPE_HARDWARE || type == PERF_TYPE_HW_CACHE) {
11288 type = event->attr.config >> PERF_PMU_TYPE_SHIFT;
11290 type = PERF_TYPE_RAW;
11292 extended_type = true;
11293 event->attr.config &= PERF_HW_EVENT_MASK;
11299 pmu = idr_find(&pmu_idr, type);
11302 if (event->attr.type != type && type != PERF_TYPE_RAW &&
11303 !(pmu->capabilities & PERF_PMU_CAP_EXTENDED_HW_TYPE))
11306 ret = perf_try_init_event(pmu, event);
11307 if (ret == -ENOENT && event->attr.type != type && !extended_type) {
11308 type = event->attr.type;
11313 pmu = ERR_PTR(ret);
11318 list_for_each_entry_rcu(pmu, &pmus, entry, lockdep_is_held(&pmus_srcu)) {
11319 ret = perf_try_init_event(pmu, event);
11323 if (ret != -ENOENT) {
11324 pmu = ERR_PTR(ret);
11329 pmu = ERR_PTR(-ENOENT);
11331 srcu_read_unlock(&pmus_srcu, idx);
11336 static void attach_sb_event(struct perf_event *event)
11338 struct pmu_event_list *pel = per_cpu_ptr(&pmu_sb_events, event->cpu);
11340 raw_spin_lock(&pel->lock);
11341 list_add_rcu(&event->sb_list, &pel->list);
11342 raw_spin_unlock(&pel->lock);
11346 * We keep a list of all !task (and therefore per-cpu) events
11347 * that need to receive side-band records.
11349 * This avoids having to scan all the various PMU per-cpu contexts
11350 * looking for them.
11352 static void account_pmu_sb_event(struct perf_event *event)
11354 if (is_sb_event(event))
11355 attach_sb_event(event);
11358 static void account_event_cpu(struct perf_event *event, int cpu)
11363 if (is_cgroup_event(event))
11364 atomic_inc(&per_cpu(perf_cgroup_events, cpu));
11367 /* Freq events need the tick to stay alive (see perf_event_task_tick). */
11368 static void account_freq_event_nohz(void)
11370 #ifdef CONFIG_NO_HZ_FULL
11371 /* Lock so we don't race with concurrent unaccount */
11372 spin_lock(&nr_freq_lock);
11373 if (atomic_inc_return(&nr_freq_events) == 1)
11374 tick_nohz_dep_set(TICK_DEP_BIT_PERF_EVENTS);
11375 spin_unlock(&nr_freq_lock);
11379 static void account_freq_event(void)
11381 if (tick_nohz_full_enabled())
11382 account_freq_event_nohz();
11384 atomic_inc(&nr_freq_events);
11388 static void account_event(struct perf_event *event)
11395 if (event->attach_state & (PERF_ATTACH_TASK | PERF_ATTACH_SCHED_CB))
11397 if (event->attr.mmap || event->attr.mmap_data)
11398 atomic_inc(&nr_mmap_events);
11399 if (event->attr.build_id)
11400 atomic_inc(&nr_build_id_events);
11401 if (event->attr.comm)
11402 atomic_inc(&nr_comm_events);
11403 if (event->attr.namespaces)
11404 atomic_inc(&nr_namespaces_events);
11405 if (event->attr.cgroup)
11406 atomic_inc(&nr_cgroup_events);
11407 if (event->attr.task)
11408 atomic_inc(&nr_task_events);
11409 if (event->attr.freq)
11410 account_freq_event();
11411 if (event->attr.context_switch) {
11412 atomic_inc(&nr_switch_events);
11415 if (has_branch_stack(event))
11417 if (is_cgroup_event(event))
11419 if (event->attr.ksymbol)
11420 atomic_inc(&nr_ksymbol_events);
11421 if (event->attr.bpf_event)
11422 atomic_inc(&nr_bpf_events);
11423 if (event->attr.text_poke)
11424 atomic_inc(&nr_text_poke_events);
11428 * We need the mutex here because static_branch_enable()
11429 * must complete *before* the perf_sched_count increment
11432 if (atomic_inc_not_zero(&perf_sched_count))
11435 mutex_lock(&perf_sched_mutex);
11436 if (!atomic_read(&perf_sched_count)) {
11437 static_branch_enable(&perf_sched_events);
11439 * Guarantee that all CPUs observe they key change and
11440 * call the perf scheduling hooks before proceeding to
11441 * install events that need them.
11446 * Now that we have waited for the sync_sched(), allow further
11447 * increments to by-pass the mutex.
11449 atomic_inc(&perf_sched_count);
11450 mutex_unlock(&perf_sched_mutex);
11454 account_event_cpu(event, event->cpu);
11456 account_pmu_sb_event(event);
11460 * Allocate and initialize an event structure
11462 static struct perf_event *
11463 perf_event_alloc(struct perf_event_attr *attr, int cpu,
11464 struct task_struct *task,
11465 struct perf_event *group_leader,
11466 struct perf_event *parent_event,
11467 perf_overflow_handler_t overflow_handler,
11468 void *context, int cgroup_fd)
11471 struct perf_event *event;
11472 struct hw_perf_event *hwc;
11473 long err = -EINVAL;
11476 if ((unsigned)cpu >= nr_cpu_ids) {
11477 if (!task || cpu != -1)
11478 return ERR_PTR(-EINVAL);
11480 if (attr->sigtrap && !task) {
11481 /* Requires a task: avoid signalling random tasks. */
11482 return ERR_PTR(-EINVAL);
11485 node = (cpu >= 0) ? cpu_to_node(cpu) : -1;
11486 event = kmem_cache_alloc_node(perf_event_cache, GFP_KERNEL | __GFP_ZERO,
11489 return ERR_PTR(-ENOMEM);
11492 * Single events are their own group leaders, with an
11493 * empty sibling list:
11496 group_leader = event;
11498 mutex_init(&event->child_mutex);
11499 INIT_LIST_HEAD(&event->child_list);
11501 INIT_LIST_HEAD(&event->event_entry);
11502 INIT_LIST_HEAD(&event->sibling_list);
11503 INIT_LIST_HEAD(&event->active_list);
11504 init_event_group(event);
11505 INIT_LIST_HEAD(&event->rb_entry);
11506 INIT_LIST_HEAD(&event->active_entry);
11507 INIT_LIST_HEAD(&event->addr_filters.list);
11508 INIT_HLIST_NODE(&event->hlist_entry);
11511 init_waitqueue_head(&event->waitq);
11512 event->pending_disable = -1;
11513 init_irq_work(&event->pending, perf_pending_event);
11515 mutex_init(&event->mmap_mutex);
11516 raw_spin_lock_init(&event->addr_filters.lock);
11518 atomic_long_set(&event->refcount, 1);
11520 event->attr = *attr;
11521 event->group_leader = group_leader;
11525 event->parent = parent_event;
11527 event->ns = get_pid_ns(task_active_pid_ns(current));
11528 event->id = atomic64_inc_return(&perf_event_id);
11530 event->state = PERF_EVENT_STATE_INACTIVE;
11533 event->event_caps = parent_event->event_caps;
11535 if (event->attr.sigtrap)
11536 atomic_set(&event->event_limit, 1);
11539 event->attach_state = PERF_ATTACH_TASK;
11541 * XXX pmu::event_init needs to know what task to account to
11542 * and we cannot use the ctx information because we need the
11543 * pmu before we get a ctx.
11545 event->hw.target = get_task_struct(task);
11548 event->clock = &local_clock;
11550 event->clock = parent_event->clock;
11552 if (!overflow_handler && parent_event) {
11553 overflow_handler = parent_event->overflow_handler;
11554 context = parent_event->overflow_handler_context;
11555 #if defined(CONFIG_BPF_SYSCALL) && defined(CONFIG_EVENT_TRACING)
11556 if (overflow_handler == bpf_overflow_handler) {
11557 struct bpf_prog *prog = parent_event->prog;
11559 bpf_prog_inc(prog);
11560 event->prog = prog;
11561 event->orig_overflow_handler =
11562 parent_event->orig_overflow_handler;
11567 if (overflow_handler) {
11568 event->overflow_handler = overflow_handler;
11569 event->overflow_handler_context = context;
11570 } else if (is_write_backward(event)){
11571 event->overflow_handler = perf_event_output_backward;
11572 event->overflow_handler_context = NULL;
11574 event->overflow_handler = perf_event_output_forward;
11575 event->overflow_handler_context = NULL;
11578 perf_event__state_init(event);
11583 hwc->sample_period = attr->sample_period;
11584 if (attr->freq && attr->sample_freq)
11585 hwc->sample_period = 1;
11586 hwc->last_period = hwc->sample_period;
11588 local64_set(&hwc->period_left, hwc->sample_period);
11591 * We currently do not support PERF_SAMPLE_READ on inherited events.
11592 * See perf_output_read().
11594 if (attr->inherit && (attr->sample_type & PERF_SAMPLE_READ))
11597 if (!has_branch_stack(event))
11598 event->attr.branch_sample_type = 0;
11600 pmu = perf_init_event(event);
11602 err = PTR_ERR(pmu);
11607 * Disallow uncore-cgroup events, they don't make sense as the cgroup will
11608 * be different on other CPUs in the uncore mask.
11610 if (pmu->task_ctx_nr == perf_invalid_context && cgroup_fd != -1) {
11615 if (event->attr.aux_output &&
11616 !(pmu->capabilities & PERF_PMU_CAP_AUX_OUTPUT)) {
11621 if (cgroup_fd != -1) {
11622 err = perf_cgroup_connect(cgroup_fd, event, attr, group_leader);
11627 err = exclusive_event_init(event);
11631 if (has_addr_filter(event)) {
11632 event->addr_filter_ranges = kcalloc(pmu->nr_addr_filters,
11633 sizeof(struct perf_addr_filter_range),
11635 if (!event->addr_filter_ranges) {
11641 * Clone the parent's vma offsets: they are valid until exec()
11642 * even if the mm is not shared with the parent.
11644 if (event->parent) {
11645 struct perf_addr_filters_head *ifh = perf_event_addr_filters(event);
11647 raw_spin_lock_irq(&ifh->lock);
11648 memcpy(event->addr_filter_ranges,
11649 event->parent->addr_filter_ranges,
11650 pmu->nr_addr_filters * sizeof(struct perf_addr_filter_range));
11651 raw_spin_unlock_irq(&ifh->lock);
11654 /* force hw sync on the address filters */
11655 event->addr_filters_gen = 1;
11658 if (!event->parent) {
11659 if (event->attr.sample_type & PERF_SAMPLE_CALLCHAIN) {
11660 err = get_callchain_buffers(attr->sample_max_stack);
11662 goto err_addr_filters;
11666 err = security_perf_event_alloc(event);
11668 goto err_callchain_buffer;
11670 /* symmetric to unaccount_event() in _free_event() */
11671 account_event(event);
11675 err_callchain_buffer:
11676 if (!event->parent) {
11677 if (event->attr.sample_type & PERF_SAMPLE_CALLCHAIN)
11678 put_callchain_buffers();
11681 kfree(event->addr_filter_ranges);
11684 exclusive_event_destroy(event);
11687 if (is_cgroup_event(event))
11688 perf_detach_cgroup(event);
11689 if (event->destroy)
11690 event->destroy(event);
11691 module_put(pmu->module);
11694 put_pid_ns(event->ns);
11695 if (event->hw.target)
11696 put_task_struct(event->hw.target);
11697 kmem_cache_free(perf_event_cache, event);
11699 return ERR_PTR(err);
11702 static int perf_copy_attr(struct perf_event_attr __user *uattr,
11703 struct perf_event_attr *attr)
11708 /* Zero the full structure, so that a short copy will be nice. */
11709 memset(attr, 0, sizeof(*attr));
11711 ret = get_user(size, &uattr->size);
11715 /* ABI compatibility quirk: */
11717 size = PERF_ATTR_SIZE_VER0;
11718 if (size < PERF_ATTR_SIZE_VER0 || size > PAGE_SIZE)
11721 ret = copy_struct_from_user(attr, sizeof(*attr), uattr, size);
11730 if (attr->__reserved_1 || attr->__reserved_2 || attr->__reserved_3)
11733 if (attr->sample_type & ~(PERF_SAMPLE_MAX-1))
11736 if (attr->read_format & ~(PERF_FORMAT_MAX-1))
11739 if (attr->sample_type & PERF_SAMPLE_BRANCH_STACK) {
11740 u64 mask = attr->branch_sample_type;
11742 /* only using defined bits */
11743 if (mask & ~(PERF_SAMPLE_BRANCH_MAX-1))
11746 /* at least one branch bit must be set */
11747 if (!(mask & ~PERF_SAMPLE_BRANCH_PLM_ALL))
11750 /* propagate priv level, when not set for branch */
11751 if (!(mask & PERF_SAMPLE_BRANCH_PLM_ALL)) {
11753 /* exclude_kernel checked on syscall entry */
11754 if (!attr->exclude_kernel)
11755 mask |= PERF_SAMPLE_BRANCH_KERNEL;
11757 if (!attr->exclude_user)
11758 mask |= PERF_SAMPLE_BRANCH_USER;
11760 if (!attr->exclude_hv)
11761 mask |= PERF_SAMPLE_BRANCH_HV;
11763 * adjust user setting (for HW filter setup)
11765 attr->branch_sample_type = mask;
11767 /* privileged levels capture (kernel, hv): check permissions */
11768 if (mask & PERF_SAMPLE_BRANCH_PERM_PLM) {
11769 ret = perf_allow_kernel(attr);
11775 if (attr->sample_type & PERF_SAMPLE_REGS_USER) {
11776 ret = perf_reg_validate(attr->sample_regs_user);
11781 if (attr->sample_type & PERF_SAMPLE_STACK_USER) {
11782 if (!arch_perf_have_user_stack_dump())
11786 * We have __u32 type for the size, but so far
11787 * we can only use __u16 as maximum due to the
11788 * __u16 sample size limit.
11790 if (attr->sample_stack_user >= USHRT_MAX)
11792 else if (!IS_ALIGNED(attr->sample_stack_user, sizeof(u64)))
11796 if (!attr->sample_max_stack)
11797 attr->sample_max_stack = sysctl_perf_event_max_stack;
11799 if (attr->sample_type & PERF_SAMPLE_REGS_INTR)
11800 ret = perf_reg_validate(attr->sample_regs_intr);
11802 #ifndef CONFIG_CGROUP_PERF
11803 if (attr->sample_type & PERF_SAMPLE_CGROUP)
11806 if ((attr->sample_type & PERF_SAMPLE_WEIGHT) &&
11807 (attr->sample_type & PERF_SAMPLE_WEIGHT_STRUCT))
11810 if (!attr->inherit && attr->inherit_thread)
11813 if (attr->remove_on_exec && attr->enable_on_exec)
11816 if (attr->sigtrap && !attr->remove_on_exec)
11823 put_user(sizeof(*attr), &uattr->size);
11829 perf_event_set_output(struct perf_event *event, struct perf_event *output_event)
11831 struct perf_buffer *rb = NULL;
11837 /* don't allow circular references */
11838 if (event == output_event)
11842 * Don't allow cross-cpu buffers
11844 if (output_event->cpu != event->cpu)
11848 * If its not a per-cpu rb, it must be the same task.
11850 if (output_event->cpu == -1 && output_event->ctx != event->ctx)
11854 * Mixing clocks in the same buffer is trouble you don't need.
11856 if (output_event->clock != event->clock)
11860 * Either writing ring buffer from beginning or from end.
11861 * Mixing is not allowed.
11863 if (is_write_backward(output_event) != is_write_backward(event))
11867 * If both events generate aux data, they must be on the same PMU
11869 if (has_aux(event) && has_aux(output_event) &&
11870 event->pmu != output_event->pmu)
11874 mutex_lock(&event->mmap_mutex);
11875 /* Can't redirect output if we've got an active mmap() */
11876 if (atomic_read(&event->mmap_count))
11879 if (output_event) {
11880 /* get the rb we want to redirect to */
11881 rb = ring_buffer_get(output_event);
11886 ring_buffer_attach(event, rb);
11890 mutex_unlock(&event->mmap_mutex);
11896 static void mutex_lock_double(struct mutex *a, struct mutex *b)
11902 mutex_lock_nested(b, SINGLE_DEPTH_NESTING);
11905 static int perf_event_set_clock(struct perf_event *event, clockid_t clk_id)
11907 bool nmi_safe = false;
11910 case CLOCK_MONOTONIC:
11911 event->clock = &ktime_get_mono_fast_ns;
11915 case CLOCK_MONOTONIC_RAW:
11916 event->clock = &ktime_get_raw_fast_ns;
11920 case CLOCK_REALTIME:
11921 event->clock = &ktime_get_real_ns;
11924 case CLOCK_BOOTTIME:
11925 event->clock = &ktime_get_boottime_ns;
11929 event->clock = &ktime_get_clocktai_ns;
11936 if (!nmi_safe && !(event->pmu->capabilities & PERF_PMU_CAP_NO_NMI))
11943 * Variation on perf_event_ctx_lock_nested(), except we take two context
11946 static struct perf_event_context *
11947 __perf_event_ctx_lock_double(struct perf_event *group_leader,
11948 struct perf_event_context *ctx)
11950 struct perf_event_context *gctx;
11954 gctx = READ_ONCE(group_leader->ctx);
11955 if (!refcount_inc_not_zero(&gctx->refcount)) {
11961 mutex_lock_double(&gctx->mutex, &ctx->mutex);
11963 if (group_leader->ctx != gctx) {
11964 mutex_unlock(&ctx->mutex);
11965 mutex_unlock(&gctx->mutex);
11974 perf_check_permission(struct perf_event_attr *attr, struct task_struct *task)
11976 unsigned int ptrace_mode = PTRACE_MODE_READ_REALCREDS;
11977 bool is_capable = perfmon_capable();
11979 if (attr->sigtrap) {
11981 * perf_event_attr::sigtrap sends signals to the other task.
11982 * Require the current task to also have CAP_KILL.
11985 is_capable &= ns_capable(__task_cred(task)->user_ns, CAP_KILL);
11989 * If the required capabilities aren't available, checks for
11990 * ptrace permissions: upgrade to ATTACH, since sending signals
11991 * can effectively change the target task.
11993 ptrace_mode = PTRACE_MODE_ATTACH_REALCREDS;
11997 * Preserve ptrace permission check for backwards compatibility. The
11998 * ptrace check also includes checks that the current task and other
11999 * task have matching uids, and is therefore not done here explicitly.
12001 return is_capable || ptrace_may_access(task, ptrace_mode);
12005 * sys_perf_event_open - open a performance event, associate it to a task/cpu
12007 * @attr_uptr: event_id type attributes for monitoring/sampling
12010 * @group_fd: group leader event fd
12011 * @flags: perf event open flags
12013 SYSCALL_DEFINE5(perf_event_open,
12014 struct perf_event_attr __user *, attr_uptr,
12015 pid_t, pid, int, cpu, int, group_fd, unsigned long, flags)
12017 struct perf_event *group_leader = NULL, *output_event = NULL;
12018 struct perf_event *event, *sibling;
12019 struct perf_event_attr attr;
12020 struct perf_event_context *ctx, *gctx;
12021 struct file *event_file = NULL;
12022 struct fd group = {NULL, 0};
12023 struct task_struct *task = NULL;
12026 int move_group = 0;
12028 int f_flags = O_RDWR;
12029 int cgroup_fd = -1;
12031 /* for future expandability... */
12032 if (flags & ~PERF_FLAG_ALL)
12035 /* Do we allow access to perf_event_open(2) ? */
12036 err = security_perf_event_open(&attr, PERF_SECURITY_OPEN);
12040 err = perf_copy_attr(attr_uptr, &attr);
12044 if (!attr.exclude_kernel) {
12045 err = perf_allow_kernel(&attr);
12050 if (attr.namespaces) {
12051 if (!perfmon_capable())
12056 if (attr.sample_freq > sysctl_perf_event_sample_rate)
12059 if (attr.sample_period & (1ULL << 63))
12063 /* Only privileged users can get physical addresses */
12064 if ((attr.sample_type & PERF_SAMPLE_PHYS_ADDR)) {
12065 err = perf_allow_kernel(&attr);
12070 /* REGS_INTR can leak data, lockdown must prevent this */
12071 if (attr.sample_type & PERF_SAMPLE_REGS_INTR) {
12072 err = security_locked_down(LOCKDOWN_PERF);
12078 * In cgroup mode, the pid argument is used to pass the fd
12079 * opened to the cgroup directory in cgroupfs. The cpu argument
12080 * designates the cpu on which to monitor threads from that
12083 if ((flags & PERF_FLAG_PID_CGROUP) && (pid == -1 || cpu == -1))
12086 if (flags & PERF_FLAG_FD_CLOEXEC)
12087 f_flags |= O_CLOEXEC;
12089 event_fd = get_unused_fd_flags(f_flags);
12093 if (group_fd != -1) {
12094 err = perf_fget_light(group_fd, &group);
12097 group_leader = group.file->private_data;
12098 if (flags & PERF_FLAG_FD_OUTPUT)
12099 output_event = group_leader;
12100 if (flags & PERF_FLAG_FD_NO_GROUP)
12101 group_leader = NULL;
12104 if (pid != -1 && !(flags & PERF_FLAG_PID_CGROUP)) {
12105 task = find_lively_task_by_vpid(pid);
12106 if (IS_ERR(task)) {
12107 err = PTR_ERR(task);
12112 if (task && group_leader &&
12113 group_leader->attr.inherit != attr.inherit) {
12118 if (flags & PERF_FLAG_PID_CGROUP)
12121 event = perf_event_alloc(&attr, cpu, task, group_leader, NULL,
12122 NULL, NULL, cgroup_fd);
12123 if (IS_ERR(event)) {
12124 err = PTR_ERR(event);
12128 if (is_sampling_event(event)) {
12129 if (event->pmu->capabilities & PERF_PMU_CAP_NO_INTERRUPT) {
12136 * Special case software events and allow them to be part of
12137 * any hardware group.
12141 if (attr.use_clockid) {
12142 err = perf_event_set_clock(event, attr.clockid);
12147 if (pmu->task_ctx_nr == perf_sw_context)
12148 event->event_caps |= PERF_EV_CAP_SOFTWARE;
12150 if (group_leader) {
12151 if (is_software_event(event) &&
12152 !in_software_context(group_leader)) {
12154 * If the event is a sw event, but the group_leader
12155 * is on hw context.
12157 * Allow the addition of software events to hw
12158 * groups, this is safe because software events
12159 * never fail to schedule.
12161 pmu = group_leader->ctx->pmu;
12162 } else if (!is_software_event(event) &&
12163 is_software_event(group_leader) &&
12164 (group_leader->group_caps & PERF_EV_CAP_SOFTWARE)) {
12166 * In case the group is a pure software group, and we
12167 * try to add a hardware event, move the whole group to
12168 * the hardware context.
12175 * Get the target context (task or percpu):
12177 ctx = find_get_context(pmu, task, event);
12179 err = PTR_ERR(ctx);
12184 * Look up the group leader (we will attach this event to it):
12186 if (group_leader) {
12190 * Do not allow a recursive hierarchy (this new sibling
12191 * becoming part of another group-sibling):
12193 if (group_leader->group_leader != group_leader)
12196 /* All events in a group should have the same clock */
12197 if (group_leader->clock != event->clock)
12201 * Make sure we're both events for the same CPU;
12202 * grouping events for different CPUs is broken; since
12203 * you can never concurrently schedule them anyhow.
12205 if (group_leader->cpu != event->cpu)
12209 * Make sure we're both on the same task, or both
12212 if (group_leader->ctx->task != ctx->task)
12216 * Do not allow to attach to a group in a different task
12217 * or CPU context. If we're moving SW events, we'll fix
12218 * this up later, so allow that.
12220 * Racy, not holding group_leader->ctx->mutex, see comment with
12221 * perf_event_ctx_lock().
12223 if (!move_group && group_leader->ctx != ctx)
12227 * Only a group leader can be exclusive or pinned
12229 if (attr.exclusive || attr.pinned)
12233 if (output_event) {
12234 err = perf_event_set_output(event, output_event);
12239 event_file = anon_inode_getfile("[perf_event]", &perf_fops, event,
12241 if (IS_ERR(event_file)) {
12242 err = PTR_ERR(event_file);
12248 err = down_read_interruptible(&task->signal->exec_update_lock);
12253 * We must hold exec_update_lock across this and any potential
12254 * perf_install_in_context() call for this new event to
12255 * serialize against exec() altering our credentials (and the
12256 * perf_event_exit_task() that could imply).
12259 if (!perf_check_permission(&attr, task))
12264 gctx = __perf_event_ctx_lock_double(group_leader, ctx);
12266 if (gctx->task == TASK_TOMBSTONE) {
12272 * Check if we raced against another sys_perf_event_open() call
12273 * moving the software group underneath us.
12275 if (!(group_leader->group_caps & PERF_EV_CAP_SOFTWARE)) {
12277 * If someone moved the group out from under us, check
12278 * if this new event wound up on the same ctx, if so
12279 * its the regular !move_group case, otherwise fail.
12285 perf_event_ctx_unlock(group_leader, gctx);
12287 goto not_move_group;
12292 * Failure to create exclusive events returns -EBUSY.
12295 if (!exclusive_event_installable(group_leader, ctx))
12298 for_each_sibling_event(sibling, group_leader) {
12299 if (!exclusive_event_installable(sibling, ctx))
12303 mutex_lock(&ctx->mutex);
12306 * Now that we hold ctx->lock, (re)validate group_leader->ctx == ctx,
12307 * see the group_leader && !move_group test earlier.
12309 if (group_leader && group_leader->ctx != ctx) {
12316 if (ctx->task == TASK_TOMBSTONE) {
12321 if (!perf_event_validate_size(event)) {
12328 * Check if the @cpu we're creating an event for is online.
12330 * We use the perf_cpu_context::ctx::mutex to serialize against
12331 * the hotplug notifiers. See perf_event_{init,exit}_cpu().
12333 struct perf_cpu_context *cpuctx =
12334 container_of(ctx, struct perf_cpu_context, ctx);
12336 if (!cpuctx->online) {
12342 if (perf_need_aux_event(event) && !perf_get_aux_event(event, group_leader)) {
12348 * Must be under the same ctx::mutex as perf_install_in_context(),
12349 * because we need to serialize with concurrent event creation.
12351 if (!exclusive_event_installable(event, ctx)) {
12356 WARN_ON_ONCE(ctx->parent_ctx);
12359 * This is the point on no return; we cannot fail hereafter. This is
12360 * where we start modifying current state.
12365 * See perf_event_ctx_lock() for comments on the details
12366 * of swizzling perf_event::ctx.
12368 perf_remove_from_context(group_leader, 0);
12371 for_each_sibling_event(sibling, group_leader) {
12372 perf_remove_from_context(sibling, 0);
12377 * Wait for everybody to stop referencing the events through
12378 * the old lists, before installing it on new lists.
12383 * Install the group siblings before the group leader.
12385 * Because a group leader will try and install the entire group
12386 * (through the sibling list, which is still in-tact), we can
12387 * end up with siblings installed in the wrong context.
12389 * By installing siblings first we NO-OP because they're not
12390 * reachable through the group lists.
12392 for_each_sibling_event(sibling, group_leader) {
12393 perf_event__state_init(sibling);
12394 perf_install_in_context(ctx, sibling, sibling->cpu);
12399 * Removing from the context ends up with disabled
12400 * event. What we want here is event in the initial
12401 * startup state, ready to be add into new context.
12403 perf_event__state_init(group_leader);
12404 perf_install_in_context(ctx, group_leader, group_leader->cpu);
12409 * Precalculate sample_data sizes; do while holding ctx::mutex such
12410 * that we're serialized against further additions and before
12411 * perf_install_in_context() which is the point the event is active and
12412 * can use these values.
12414 perf_event__header_size(event);
12415 perf_event__id_header_size(event);
12417 event->owner = current;
12419 perf_install_in_context(ctx, event, event->cpu);
12420 perf_unpin_context(ctx);
12423 perf_event_ctx_unlock(group_leader, gctx);
12424 mutex_unlock(&ctx->mutex);
12427 up_read(&task->signal->exec_update_lock);
12428 put_task_struct(task);
12431 mutex_lock(¤t->perf_event_mutex);
12432 list_add_tail(&event->owner_entry, ¤t->perf_event_list);
12433 mutex_unlock(¤t->perf_event_mutex);
12436 * Drop the reference on the group_event after placing the
12437 * new event on the sibling_list. This ensures destruction
12438 * of the group leader will find the pointer to itself in
12439 * perf_group_detach().
12442 fd_install(event_fd, event_file);
12447 perf_event_ctx_unlock(group_leader, gctx);
12448 mutex_unlock(&ctx->mutex);
12451 up_read(&task->signal->exec_update_lock);
12455 perf_unpin_context(ctx);
12459 * If event_file is set, the fput() above will have called ->release()
12460 * and that will take care of freeing the event.
12466 put_task_struct(task);
12470 put_unused_fd(event_fd);
12475 * perf_event_create_kernel_counter
12477 * @attr: attributes of the counter to create
12478 * @cpu: cpu in which the counter is bound
12479 * @task: task to profile (NULL for percpu)
12480 * @overflow_handler: callback to trigger when we hit the event
12481 * @context: context data could be used in overflow_handler callback
12483 struct perf_event *
12484 perf_event_create_kernel_counter(struct perf_event_attr *attr, int cpu,
12485 struct task_struct *task,
12486 perf_overflow_handler_t overflow_handler,
12489 struct perf_event_context *ctx;
12490 struct perf_event *event;
12494 * Grouping is not supported for kernel events, neither is 'AUX',
12495 * make sure the caller's intentions are adjusted.
12497 if (attr->aux_output)
12498 return ERR_PTR(-EINVAL);
12500 event = perf_event_alloc(attr, cpu, task, NULL, NULL,
12501 overflow_handler, context, -1);
12502 if (IS_ERR(event)) {
12503 err = PTR_ERR(event);
12507 /* Mark owner so we could distinguish it from user events. */
12508 event->owner = TASK_TOMBSTONE;
12511 * Get the target context (task or percpu):
12513 ctx = find_get_context(event->pmu, task, event);
12515 err = PTR_ERR(ctx);
12519 WARN_ON_ONCE(ctx->parent_ctx);
12520 mutex_lock(&ctx->mutex);
12521 if (ctx->task == TASK_TOMBSTONE) {
12528 * Check if the @cpu we're creating an event for is online.
12530 * We use the perf_cpu_context::ctx::mutex to serialize against
12531 * the hotplug notifiers. See perf_event_{init,exit}_cpu().
12533 struct perf_cpu_context *cpuctx =
12534 container_of(ctx, struct perf_cpu_context, ctx);
12535 if (!cpuctx->online) {
12541 if (!exclusive_event_installable(event, ctx)) {
12546 perf_install_in_context(ctx, event, event->cpu);
12547 perf_unpin_context(ctx);
12548 mutex_unlock(&ctx->mutex);
12553 mutex_unlock(&ctx->mutex);
12554 perf_unpin_context(ctx);
12559 return ERR_PTR(err);
12561 EXPORT_SYMBOL_GPL(perf_event_create_kernel_counter);
12563 void perf_pmu_migrate_context(struct pmu *pmu, int src_cpu, int dst_cpu)
12565 struct perf_event_context *src_ctx;
12566 struct perf_event_context *dst_ctx;
12567 struct perf_event *event, *tmp;
12570 src_ctx = &per_cpu_ptr(pmu->pmu_cpu_context, src_cpu)->ctx;
12571 dst_ctx = &per_cpu_ptr(pmu->pmu_cpu_context, dst_cpu)->ctx;
12574 * See perf_event_ctx_lock() for comments on the details
12575 * of swizzling perf_event::ctx.
12577 mutex_lock_double(&src_ctx->mutex, &dst_ctx->mutex);
12578 list_for_each_entry_safe(event, tmp, &src_ctx->event_list,
12580 perf_remove_from_context(event, 0);
12581 unaccount_event_cpu(event, src_cpu);
12583 list_add(&event->migrate_entry, &events);
12587 * Wait for the events to quiesce before re-instating them.
12592 * Re-instate events in 2 passes.
12594 * Skip over group leaders and only install siblings on this first
12595 * pass, siblings will not get enabled without a leader, however a
12596 * leader will enable its siblings, even if those are still on the old
12599 list_for_each_entry_safe(event, tmp, &events, migrate_entry) {
12600 if (event->group_leader == event)
12603 list_del(&event->migrate_entry);
12604 if (event->state >= PERF_EVENT_STATE_OFF)
12605 event->state = PERF_EVENT_STATE_INACTIVE;
12606 account_event_cpu(event, dst_cpu);
12607 perf_install_in_context(dst_ctx, event, dst_cpu);
12612 * Once all the siblings are setup properly, install the group leaders
12615 list_for_each_entry_safe(event, tmp, &events, migrate_entry) {
12616 list_del(&event->migrate_entry);
12617 if (event->state >= PERF_EVENT_STATE_OFF)
12618 event->state = PERF_EVENT_STATE_INACTIVE;
12619 account_event_cpu(event, dst_cpu);
12620 perf_install_in_context(dst_ctx, event, dst_cpu);
12623 mutex_unlock(&dst_ctx->mutex);
12624 mutex_unlock(&src_ctx->mutex);
12626 EXPORT_SYMBOL_GPL(perf_pmu_migrate_context);
12628 static void sync_child_event(struct perf_event *child_event)
12630 struct perf_event *parent_event = child_event->parent;
12633 if (child_event->attr.inherit_stat) {
12634 struct task_struct *task = child_event->ctx->task;
12636 if (task && task != TASK_TOMBSTONE)
12637 perf_event_read_event(child_event, task);
12640 child_val = perf_event_count(child_event);
12643 * Add back the child's count to the parent's count:
12645 atomic64_add(child_val, &parent_event->child_count);
12646 atomic64_add(child_event->total_time_enabled,
12647 &parent_event->child_total_time_enabled);
12648 atomic64_add(child_event->total_time_running,
12649 &parent_event->child_total_time_running);
12653 perf_event_exit_event(struct perf_event *event, struct perf_event_context *ctx)
12655 struct perf_event *parent_event = event->parent;
12656 unsigned long detach_flags = 0;
12658 if (parent_event) {
12660 * Do not destroy the 'original' grouping; because of the
12661 * context switch optimization the original events could've
12662 * ended up in a random child task.
12664 * If we were to destroy the original group, all group related
12665 * operations would cease to function properly after this
12666 * random child dies.
12668 * Do destroy all inherited groups, we don't care about those
12669 * and being thorough is better.
12671 detach_flags = DETACH_GROUP | DETACH_CHILD;
12672 mutex_lock(&parent_event->child_mutex);
12675 perf_remove_from_context(event, detach_flags);
12677 raw_spin_lock_irq(&ctx->lock);
12678 if (event->state > PERF_EVENT_STATE_EXIT)
12679 perf_event_set_state(event, PERF_EVENT_STATE_EXIT);
12680 raw_spin_unlock_irq(&ctx->lock);
12683 * Child events can be freed.
12685 if (parent_event) {
12686 mutex_unlock(&parent_event->child_mutex);
12688 * Kick perf_poll() for is_event_hup();
12690 perf_event_wakeup(parent_event);
12692 put_event(parent_event);
12697 * Parent events are governed by their filedesc, retain them.
12699 perf_event_wakeup(event);
12702 static void perf_event_exit_task_context(struct task_struct *child, int ctxn)
12704 struct perf_event_context *child_ctx, *clone_ctx = NULL;
12705 struct perf_event *child_event, *next;
12707 WARN_ON_ONCE(child != current);
12709 child_ctx = perf_pin_task_context(child, ctxn);
12714 * In order to reduce the amount of tricky in ctx tear-down, we hold
12715 * ctx::mutex over the entire thing. This serializes against almost
12716 * everything that wants to access the ctx.
12718 * The exception is sys_perf_event_open() /
12719 * perf_event_create_kernel_count() which does find_get_context()
12720 * without ctx::mutex (it cannot because of the move_group double mutex
12721 * lock thing). See the comments in perf_install_in_context().
12723 mutex_lock(&child_ctx->mutex);
12726 * In a single ctx::lock section, de-schedule the events and detach the
12727 * context from the task such that we cannot ever get it scheduled back
12730 raw_spin_lock_irq(&child_ctx->lock);
12731 task_ctx_sched_out(__get_cpu_context(child_ctx), child_ctx, EVENT_ALL);
12734 * Now that the context is inactive, destroy the task <-> ctx relation
12735 * and mark the context dead.
12737 RCU_INIT_POINTER(child->perf_event_ctxp[ctxn], NULL);
12738 put_ctx(child_ctx); /* cannot be last */
12739 WRITE_ONCE(child_ctx->task, TASK_TOMBSTONE);
12740 put_task_struct(current); /* cannot be last */
12742 clone_ctx = unclone_ctx(child_ctx);
12743 raw_spin_unlock_irq(&child_ctx->lock);
12746 put_ctx(clone_ctx);
12749 * Report the task dead after unscheduling the events so that we
12750 * won't get any samples after PERF_RECORD_EXIT. We can however still
12751 * get a few PERF_RECORD_READ events.
12753 perf_event_task(child, child_ctx, 0);
12755 list_for_each_entry_safe(child_event, next, &child_ctx->event_list, event_entry)
12756 perf_event_exit_event(child_event, child_ctx);
12758 mutex_unlock(&child_ctx->mutex);
12760 put_ctx(child_ctx);
12764 * When a child task exits, feed back event values to parent events.
12766 * Can be called with exec_update_lock held when called from
12767 * setup_new_exec().
12769 void perf_event_exit_task(struct task_struct *child)
12771 struct perf_event *event, *tmp;
12774 mutex_lock(&child->perf_event_mutex);
12775 list_for_each_entry_safe(event, tmp, &child->perf_event_list,
12777 list_del_init(&event->owner_entry);
12780 * Ensure the list deletion is visible before we clear
12781 * the owner, closes a race against perf_release() where
12782 * we need to serialize on the owner->perf_event_mutex.
12784 smp_store_release(&event->owner, NULL);
12786 mutex_unlock(&child->perf_event_mutex);
12788 for_each_task_context_nr(ctxn)
12789 perf_event_exit_task_context(child, ctxn);
12792 * The perf_event_exit_task_context calls perf_event_task
12793 * with child's task_ctx, which generates EXIT events for
12794 * child contexts and sets child->perf_event_ctxp[] to NULL.
12795 * At this point we need to send EXIT events to cpu contexts.
12797 perf_event_task(child, NULL, 0);
12800 static void perf_free_event(struct perf_event *event,
12801 struct perf_event_context *ctx)
12803 struct perf_event *parent = event->parent;
12805 if (WARN_ON_ONCE(!parent))
12808 mutex_lock(&parent->child_mutex);
12809 list_del_init(&event->child_list);
12810 mutex_unlock(&parent->child_mutex);
12814 raw_spin_lock_irq(&ctx->lock);
12815 perf_group_detach(event);
12816 list_del_event(event, ctx);
12817 raw_spin_unlock_irq(&ctx->lock);
12822 * Free a context as created by inheritance by perf_event_init_task() below,
12823 * used by fork() in case of fail.
12825 * Even though the task has never lived, the context and events have been
12826 * exposed through the child_list, so we must take care tearing it all down.
12828 void perf_event_free_task(struct task_struct *task)
12830 struct perf_event_context *ctx;
12831 struct perf_event *event, *tmp;
12834 for_each_task_context_nr(ctxn) {
12835 ctx = task->perf_event_ctxp[ctxn];
12839 mutex_lock(&ctx->mutex);
12840 raw_spin_lock_irq(&ctx->lock);
12842 * Destroy the task <-> ctx relation and mark the context dead.
12844 * This is important because even though the task hasn't been
12845 * exposed yet the context has been (through child_list).
12847 RCU_INIT_POINTER(task->perf_event_ctxp[ctxn], NULL);
12848 WRITE_ONCE(ctx->task, TASK_TOMBSTONE);
12849 put_task_struct(task); /* cannot be last */
12850 raw_spin_unlock_irq(&ctx->lock);
12852 list_for_each_entry_safe(event, tmp, &ctx->event_list, event_entry)
12853 perf_free_event(event, ctx);
12855 mutex_unlock(&ctx->mutex);
12858 * perf_event_release_kernel() could've stolen some of our
12859 * child events and still have them on its free_list. In that
12860 * case we must wait for these events to have been freed (in
12861 * particular all their references to this task must've been
12864 * Without this copy_process() will unconditionally free this
12865 * task (irrespective of its reference count) and
12866 * _free_event()'s put_task_struct(event->hw.target) will be a
12869 * Wait for all events to drop their context reference.
12871 wait_var_event(&ctx->refcount, refcount_read(&ctx->refcount) == 1);
12872 put_ctx(ctx); /* must be last */
12876 void perf_event_delayed_put(struct task_struct *task)
12880 for_each_task_context_nr(ctxn)
12881 WARN_ON_ONCE(task->perf_event_ctxp[ctxn]);
12884 struct file *perf_event_get(unsigned int fd)
12886 struct file *file = fget(fd);
12888 return ERR_PTR(-EBADF);
12890 if (file->f_op != &perf_fops) {
12892 return ERR_PTR(-EBADF);
12898 const struct perf_event *perf_get_event(struct file *file)
12900 if (file->f_op != &perf_fops)
12901 return ERR_PTR(-EINVAL);
12903 return file->private_data;
12906 const struct perf_event_attr *perf_event_attrs(struct perf_event *event)
12909 return ERR_PTR(-EINVAL);
12911 return &event->attr;
12915 * Inherit an event from parent task to child task.
12918 * - valid pointer on success
12919 * - NULL for orphaned events
12920 * - IS_ERR() on error
12922 static struct perf_event *
12923 inherit_event(struct perf_event *parent_event,
12924 struct task_struct *parent,
12925 struct perf_event_context *parent_ctx,
12926 struct task_struct *child,
12927 struct perf_event *group_leader,
12928 struct perf_event_context *child_ctx)
12930 enum perf_event_state parent_state = parent_event->state;
12931 struct perf_event *child_event;
12932 unsigned long flags;
12935 * Instead of creating recursive hierarchies of events,
12936 * we link inherited events back to the original parent,
12937 * which has a filp for sure, which we use as the reference
12940 if (parent_event->parent)
12941 parent_event = parent_event->parent;
12943 child_event = perf_event_alloc(&parent_event->attr,
12946 group_leader, parent_event,
12948 if (IS_ERR(child_event))
12949 return child_event;
12952 if ((child_event->attach_state & PERF_ATTACH_TASK_DATA) &&
12953 !child_ctx->task_ctx_data) {
12954 struct pmu *pmu = child_event->pmu;
12956 child_ctx->task_ctx_data = alloc_task_ctx_data(pmu);
12957 if (!child_ctx->task_ctx_data) {
12958 free_event(child_event);
12959 return ERR_PTR(-ENOMEM);
12964 * is_orphaned_event() and list_add_tail(&parent_event->child_list)
12965 * must be under the same lock in order to serialize against
12966 * perf_event_release_kernel(), such that either we must observe
12967 * is_orphaned_event() or they will observe us on the child_list.
12969 mutex_lock(&parent_event->child_mutex);
12970 if (is_orphaned_event(parent_event) ||
12971 !atomic_long_inc_not_zero(&parent_event->refcount)) {
12972 mutex_unlock(&parent_event->child_mutex);
12973 /* task_ctx_data is freed with child_ctx */
12974 free_event(child_event);
12978 get_ctx(child_ctx);
12981 * Make the child state follow the state of the parent event,
12982 * not its attr.disabled bit. We hold the parent's mutex,
12983 * so we won't race with perf_event_{en, dis}able_family.
12985 if (parent_state >= PERF_EVENT_STATE_INACTIVE)
12986 child_event->state = PERF_EVENT_STATE_INACTIVE;
12988 child_event->state = PERF_EVENT_STATE_OFF;
12990 if (parent_event->attr.freq) {
12991 u64 sample_period = parent_event->hw.sample_period;
12992 struct hw_perf_event *hwc = &child_event->hw;
12994 hwc->sample_period = sample_period;
12995 hwc->last_period = sample_period;
12997 local64_set(&hwc->period_left, sample_period);
13000 child_event->ctx = child_ctx;
13001 child_event->overflow_handler = parent_event->overflow_handler;
13002 child_event->overflow_handler_context
13003 = parent_event->overflow_handler_context;
13006 * Precalculate sample_data sizes
13008 perf_event__header_size(child_event);
13009 perf_event__id_header_size(child_event);
13012 * Link it up in the child's context:
13014 raw_spin_lock_irqsave(&child_ctx->lock, flags);
13015 add_event_to_ctx(child_event, child_ctx);
13016 child_event->attach_state |= PERF_ATTACH_CHILD;
13017 raw_spin_unlock_irqrestore(&child_ctx->lock, flags);
13020 * Link this into the parent event's child list
13022 list_add_tail(&child_event->child_list, &parent_event->child_list);
13023 mutex_unlock(&parent_event->child_mutex);
13025 return child_event;
13029 * Inherits an event group.
13031 * This will quietly suppress orphaned events; !inherit_event() is not an error.
13032 * This matches with perf_event_release_kernel() removing all child events.
13038 static int inherit_group(struct perf_event *parent_event,
13039 struct task_struct *parent,
13040 struct perf_event_context *parent_ctx,
13041 struct task_struct *child,
13042 struct perf_event_context *child_ctx)
13044 struct perf_event *leader;
13045 struct perf_event *sub;
13046 struct perf_event *child_ctr;
13048 leader = inherit_event(parent_event, parent, parent_ctx,
13049 child, NULL, child_ctx);
13050 if (IS_ERR(leader))
13051 return PTR_ERR(leader);
13053 * @leader can be NULL here because of is_orphaned_event(). In this
13054 * case inherit_event() will create individual events, similar to what
13055 * perf_group_detach() would do anyway.
13057 for_each_sibling_event(sub, parent_event) {
13058 child_ctr = inherit_event(sub, parent, parent_ctx,
13059 child, leader, child_ctx);
13060 if (IS_ERR(child_ctr))
13061 return PTR_ERR(child_ctr);
13063 if (sub->aux_event == parent_event && child_ctr &&
13064 !perf_get_aux_event(child_ctr, leader))
13071 * Creates the child task context and tries to inherit the event-group.
13073 * Clears @inherited_all on !attr.inherited or error. Note that we'll leave
13074 * inherited_all set when we 'fail' to inherit an orphaned event; this is
13075 * consistent with perf_event_release_kernel() removing all child events.
13082 inherit_task_group(struct perf_event *event, struct task_struct *parent,
13083 struct perf_event_context *parent_ctx,
13084 struct task_struct *child, int ctxn,
13085 u64 clone_flags, int *inherited_all)
13088 struct perf_event_context *child_ctx;
13090 if (!event->attr.inherit ||
13091 (event->attr.inherit_thread && !(clone_flags & CLONE_THREAD)) ||
13092 /* Do not inherit if sigtrap and signal handlers were cleared. */
13093 (event->attr.sigtrap && (clone_flags & CLONE_CLEAR_SIGHAND))) {
13094 *inherited_all = 0;
13098 child_ctx = child->perf_event_ctxp[ctxn];
13101 * This is executed from the parent task context, so
13102 * inherit events that have been marked for cloning.
13103 * First allocate and initialize a context for the
13106 child_ctx = alloc_perf_context(parent_ctx->pmu, child);
13110 child->perf_event_ctxp[ctxn] = child_ctx;
13113 ret = inherit_group(event, parent, parent_ctx,
13117 *inherited_all = 0;
13123 * Initialize the perf_event context in task_struct
13125 static int perf_event_init_context(struct task_struct *child, int ctxn,
13128 struct perf_event_context *child_ctx, *parent_ctx;
13129 struct perf_event_context *cloned_ctx;
13130 struct perf_event *event;
13131 struct task_struct *parent = current;
13132 int inherited_all = 1;
13133 unsigned long flags;
13136 if (likely(!parent->perf_event_ctxp[ctxn]))
13140 * If the parent's context is a clone, pin it so it won't get
13141 * swapped under us.
13143 parent_ctx = perf_pin_task_context(parent, ctxn);
13148 * No need to check if parent_ctx != NULL here; since we saw
13149 * it non-NULL earlier, the only reason for it to become NULL
13150 * is if we exit, and since we're currently in the middle of
13151 * a fork we can't be exiting at the same time.
13155 * Lock the parent list. No need to lock the child - not PID
13156 * hashed yet and not running, so nobody can access it.
13158 mutex_lock(&parent_ctx->mutex);
13161 * We dont have to disable NMIs - we are only looking at
13162 * the list, not manipulating it:
13164 perf_event_groups_for_each(event, &parent_ctx->pinned_groups) {
13165 ret = inherit_task_group(event, parent, parent_ctx,
13166 child, ctxn, clone_flags,
13173 * We can't hold ctx->lock when iterating the ->flexible_group list due
13174 * to allocations, but we need to prevent rotation because
13175 * rotate_ctx() will change the list from interrupt context.
13177 raw_spin_lock_irqsave(&parent_ctx->lock, flags);
13178 parent_ctx->rotate_disable = 1;
13179 raw_spin_unlock_irqrestore(&parent_ctx->lock, flags);
13181 perf_event_groups_for_each(event, &parent_ctx->flexible_groups) {
13182 ret = inherit_task_group(event, parent, parent_ctx,
13183 child, ctxn, clone_flags,
13189 raw_spin_lock_irqsave(&parent_ctx->lock, flags);
13190 parent_ctx->rotate_disable = 0;
13192 child_ctx = child->perf_event_ctxp[ctxn];
13194 if (child_ctx && inherited_all) {
13196 * Mark the child context as a clone of the parent
13197 * context, or of whatever the parent is a clone of.
13199 * Note that if the parent is a clone, the holding of
13200 * parent_ctx->lock avoids it from being uncloned.
13202 cloned_ctx = parent_ctx->parent_ctx;
13204 child_ctx->parent_ctx = cloned_ctx;
13205 child_ctx->parent_gen = parent_ctx->parent_gen;
13207 child_ctx->parent_ctx = parent_ctx;
13208 child_ctx->parent_gen = parent_ctx->generation;
13210 get_ctx(child_ctx->parent_ctx);
13213 raw_spin_unlock_irqrestore(&parent_ctx->lock, flags);
13215 mutex_unlock(&parent_ctx->mutex);
13217 perf_unpin_context(parent_ctx);
13218 put_ctx(parent_ctx);
13224 * Initialize the perf_event context in task_struct
13226 int perf_event_init_task(struct task_struct *child, u64 clone_flags)
13230 memset(child->perf_event_ctxp, 0, sizeof(child->perf_event_ctxp));
13231 mutex_init(&child->perf_event_mutex);
13232 INIT_LIST_HEAD(&child->perf_event_list);
13234 for_each_task_context_nr(ctxn) {
13235 ret = perf_event_init_context(child, ctxn, clone_flags);
13237 perf_event_free_task(child);
13245 static void __init perf_event_init_all_cpus(void)
13247 struct swevent_htable *swhash;
13250 zalloc_cpumask_var(&perf_online_mask, GFP_KERNEL);
13252 for_each_possible_cpu(cpu) {
13253 swhash = &per_cpu(swevent_htable, cpu);
13254 mutex_init(&swhash->hlist_mutex);
13255 INIT_LIST_HEAD(&per_cpu(active_ctx_list, cpu));
13257 INIT_LIST_HEAD(&per_cpu(pmu_sb_events.list, cpu));
13258 raw_spin_lock_init(&per_cpu(pmu_sb_events.lock, cpu));
13260 #ifdef CONFIG_CGROUP_PERF
13261 INIT_LIST_HEAD(&per_cpu(cgrp_cpuctx_list, cpu));
13263 INIT_LIST_HEAD(&per_cpu(sched_cb_list, cpu));
13267 static void perf_swevent_init_cpu(unsigned int cpu)
13269 struct swevent_htable *swhash = &per_cpu(swevent_htable, cpu);
13271 mutex_lock(&swhash->hlist_mutex);
13272 if (swhash->hlist_refcount > 0 && !swevent_hlist_deref(swhash)) {
13273 struct swevent_hlist *hlist;
13275 hlist = kzalloc_node(sizeof(*hlist), GFP_KERNEL, cpu_to_node(cpu));
13277 rcu_assign_pointer(swhash->swevent_hlist, hlist);
13279 mutex_unlock(&swhash->hlist_mutex);
13282 #if defined CONFIG_HOTPLUG_CPU || defined CONFIG_KEXEC_CORE
13283 static void __perf_event_exit_context(void *__info)
13285 struct perf_event_context *ctx = __info;
13286 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
13287 struct perf_event *event;
13289 raw_spin_lock(&ctx->lock);
13290 ctx_sched_out(ctx, cpuctx, EVENT_TIME);
13291 list_for_each_entry(event, &ctx->event_list, event_entry)
13292 __perf_remove_from_context(event, cpuctx, ctx, (void *)DETACH_GROUP);
13293 raw_spin_unlock(&ctx->lock);
13296 static void perf_event_exit_cpu_context(int cpu)
13298 struct perf_cpu_context *cpuctx;
13299 struct perf_event_context *ctx;
13302 mutex_lock(&pmus_lock);
13303 list_for_each_entry(pmu, &pmus, entry) {
13304 cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
13305 ctx = &cpuctx->ctx;
13307 mutex_lock(&ctx->mutex);
13308 smp_call_function_single(cpu, __perf_event_exit_context, ctx, 1);
13309 cpuctx->online = 0;
13310 mutex_unlock(&ctx->mutex);
13312 cpumask_clear_cpu(cpu, perf_online_mask);
13313 mutex_unlock(&pmus_lock);
13317 static void perf_event_exit_cpu_context(int cpu) { }
13321 int perf_event_init_cpu(unsigned int cpu)
13323 struct perf_cpu_context *cpuctx;
13324 struct perf_event_context *ctx;
13327 perf_swevent_init_cpu(cpu);
13329 mutex_lock(&pmus_lock);
13330 cpumask_set_cpu(cpu, perf_online_mask);
13331 list_for_each_entry(pmu, &pmus, entry) {
13332 cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
13333 ctx = &cpuctx->ctx;
13335 mutex_lock(&ctx->mutex);
13336 cpuctx->online = 1;
13337 mutex_unlock(&ctx->mutex);
13339 mutex_unlock(&pmus_lock);
13344 int perf_event_exit_cpu(unsigned int cpu)
13346 perf_event_exit_cpu_context(cpu);
13351 perf_reboot(struct notifier_block *notifier, unsigned long val, void *v)
13355 for_each_online_cpu(cpu)
13356 perf_event_exit_cpu(cpu);
13362 * Run the perf reboot notifier at the very last possible moment so that
13363 * the generic watchdog code runs as long as possible.
13365 static struct notifier_block perf_reboot_notifier = {
13366 .notifier_call = perf_reboot,
13367 .priority = INT_MIN,
13370 void __init perf_event_init(void)
13374 idr_init(&pmu_idr);
13376 perf_event_init_all_cpus();
13377 init_srcu_struct(&pmus_srcu);
13378 perf_pmu_register(&perf_swevent, "software", PERF_TYPE_SOFTWARE);
13379 perf_pmu_register(&perf_cpu_clock, NULL, -1);
13380 perf_pmu_register(&perf_task_clock, NULL, -1);
13381 perf_tp_register();
13382 perf_event_init_cpu(smp_processor_id());
13383 register_reboot_notifier(&perf_reboot_notifier);
13385 ret = init_hw_breakpoint();
13386 WARN(ret, "hw_breakpoint initialization failed with: %d", ret);
13388 perf_event_cache = KMEM_CACHE(perf_event, SLAB_PANIC);
13391 * Build time assertion that we keep the data_head at the intended
13392 * location. IOW, validation we got the __reserved[] size right.
13394 BUILD_BUG_ON((offsetof(struct perf_event_mmap_page, data_head))
13398 ssize_t perf_event_sysfs_show(struct device *dev, struct device_attribute *attr,
13401 struct perf_pmu_events_attr *pmu_attr =
13402 container_of(attr, struct perf_pmu_events_attr, attr);
13404 if (pmu_attr->event_str)
13405 return sprintf(page, "%s\n", pmu_attr->event_str);
13409 EXPORT_SYMBOL_GPL(perf_event_sysfs_show);
13411 static int __init perf_event_sysfs_init(void)
13416 mutex_lock(&pmus_lock);
13418 ret = bus_register(&pmu_bus);
13422 list_for_each_entry(pmu, &pmus, entry) {
13423 if (!pmu->name || pmu->type < 0)
13426 ret = pmu_dev_alloc(pmu);
13427 WARN(ret, "Failed to register pmu: %s, reason %d\n", pmu->name, ret);
13429 pmu_bus_running = 1;
13433 mutex_unlock(&pmus_lock);
13437 device_initcall(perf_event_sysfs_init);
13439 #ifdef CONFIG_CGROUP_PERF
13440 static struct cgroup_subsys_state *
13441 perf_cgroup_css_alloc(struct cgroup_subsys_state *parent_css)
13443 struct perf_cgroup *jc;
13445 jc = kzalloc(sizeof(*jc), GFP_KERNEL);
13447 return ERR_PTR(-ENOMEM);
13449 jc->info = alloc_percpu(struct perf_cgroup_info);
13452 return ERR_PTR(-ENOMEM);
13458 static void perf_cgroup_css_free(struct cgroup_subsys_state *css)
13460 struct perf_cgroup *jc = container_of(css, struct perf_cgroup, css);
13462 free_percpu(jc->info);
13466 static int perf_cgroup_css_online(struct cgroup_subsys_state *css)
13468 perf_event_cgroup(css->cgroup);
13472 static int __perf_cgroup_move(void *info)
13474 struct task_struct *task = info;
13476 perf_cgroup_switch(task);
13481 static void perf_cgroup_attach(struct cgroup_taskset *tset)
13483 struct task_struct *task;
13484 struct cgroup_subsys_state *css;
13486 cgroup_taskset_for_each(task, css, tset)
13487 task_function_call(task, __perf_cgroup_move, task);
13490 struct cgroup_subsys perf_event_cgrp_subsys = {
13491 .css_alloc = perf_cgroup_css_alloc,
13492 .css_free = perf_cgroup_css_free,
13493 .css_online = perf_cgroup_css_online,
13494 .attach = perf_cgroup_attach,
13496 * Implicitly enable on dfl hierarchy so that perf events can
13497 * always be filtered by cgroup2 path as long as perf_event
13498 * controller is not mounted on a legacy hierarchy.
13500 .implicit_on_dfl = true,
13503 #endif /* CONFIG_CGROUP_PERF */
13505 DEFINE_STATIC_CALL_RET0(perf_snapshot_branch_stack, perf_snapshot_branch_stack_t);