/* * Performance events core code: * * Copyright (C) 2008 Thomas Gleixner * Copyright (C) 2008-2011 Red Hat, Inc., Ingo Molnar * Copyright (C) 2008-2011 Red Hat, Inc., Peter Zijlstra * Copyright © 2009 Paul Mackerras, IBM Corp. * * For licensing details see kernel-base/COPYING */ #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include "internal.h" #include struct remote_function_call { struct task_struct *p; int (*func)(void *info); void *info; int ret; }; static void remote_function(void *data) { struct remote_function_call *tfc = data; struct task_struct *p = tfc->p; if (p) { tfc->ret = -EAGAIN; if (task_cpu(p) != smp_processor_id() || !task_curr(p)) return; } tfc->ret = tfc->func(tfc->info); } /** * task_function_call - call a function on the cpu on which a task runs * @p: the task to evaluate * @func: the function to be called * @info: the function call argument * * Calls the function @func when the task is currently running. This might * be on the current CPU, which just calls the function directly * * returns: @func return value, or * -ESRCH - when the process isn't running * -EAGAIN - when the process moved away */ static int task_function_call(struct task_struct *p, int (*func) (void *info), void *info) { struct remote_function_call data = { .p = p, .func = func, .info = info, .ret = -ESRCH, /* No such (running) process */ }; if (task_curr(p)) smp_call_function_single(task_cpu(p), remote_function, &data, 1); return data.ret; } /** * cpu_function_call - call a function on the cpu * @func: the function to be called * @info: the function call argument * * Calls the function @func on the remote cpu. * * returns: @func return value or -ENXIO when the cpu is offline */ static int cpu_function_call(int cpu, int (*func) (void *info), void *info) { struct remote_function_call data = { .p = NULL, .func = func, .info = info, .ret = -ENXIO, /* No such CPU */ }; smp_call_function_single(cpu, remote_function, &data, 1); return data.ret; } #define PERF_FLAG_ALL (PERF_FLAG_FD_NO_GROUP |\ PERF_FLAG_FD_OUTPUT |\ PERF_FLAG_PID_CGROUP) /* * branch priv levels that need permission checks */ #define PERF_SAMPLE_BRANCH_PERM_PLM \ (PERF_SAMPLE_BRANCH_KERNEL |\ PERF_SAMPLE_BRANCH_HV) enum event_type_t { EVENT_FLEXIBLE = 0x1, EVENT_PINNED = 0x2, EVENT_ALL = EVENT_FLEXIBLE | EVENT_PINNED, }; /* * perf_sched_events : >0 events exist * perf_cgroup_events: >0 per-cpu cgroup events exist on this cpu */ struct static_key_deferred perf_sched_events __read_mostly; static DEFINE_PER_CPU(atomic_t, perf_cgroup_events); static DEFINE_PER_CPU(atomic_t, perf_branch_stack_events); static atomic_t nr_mmap_events __read_mostly; static atomic_t nr_comm_events __read_mostly; static atomic_t nr_task_events __read_mostly; static LIST_HEAD(pmus); static DEFINE_MUTEX(pmus_lock); static struct srcu_struct pmus_srcu; /* * perf event paranoia level: * -1 - not paranoid at all * 0 - disallow raw tracepoint access for unpriv * 1 - disallow cpu events for unpriv * 2 - disallow kernel profiling for unpriv */ int sysctl_perf_event_paranoid __read_mostly = 1; /* Minimum for 512 kiB + 1 user control page */ int sysctl_perf_event_mlock __read_mostly = 512 + (PAGE_SIZE / 1024); /* 'free' kiB per user */ /* * max perf event sample rate */ #define DEFAULT_MAX_SAMPLE_RATE 100000 #define DEFAULT_SAMPLE_PERIOD_NS (NSEC_PER_SEC / DEFAULT_MAX_SAMPLE_RATE) #define DEFAULT_CPU_TIME_MAX_PERCENT 25 int sysctl_perf_event_sample_rate __read_mostly = DEFAULT_MAX_SAMPLE_RATE; static int max_samples_per_tick __read_mostly = DIV_ROUND_UP(DEFAULT_MAX_SAMPLE_RATE, HZ); static int perf_sample_period_ns __read_mostly = DEFAULT_SAMPLE_PERIOD_NS; static atomic_t perf_sample_allowed_ns __read_mostly = ATOMIC_INIT( DEFAULT_SAMPLE_PERIOD_NS * DEFAULT_CPU_TIME_MAX_PERCENT / 100); void update_perf_cpu_limits(void) { u64 tmp = perf_sample_period_ns; tmp *= sysctl_perf_cpu_time_max_percent; do_div(tmp, 100); atomic_set(&perf_sample_allowed_ns, tmp); } int perf_proc_update_handler(struct ctl_table *table, int write, void __user *buffer, size_t *lenp, loff_t *ppos) { int ret = proc_dointvec_minmax(table, write, buffer, lenp, ppos); if (ret || !write) return ret; max_samples_per_tick = DIV_ROUND_UP(sysctl_perf_event_sample_rate, HZ); perf_sample_period_ns = NSEC_PER_SEC / sysctl_perf_event_sample_rate; update_perf_cpu_limits(); return 0; } int sysctl_perf_cpu_time_max_percent __read_mostly = DEFAULT_CPU_TIME_MAX_PERCENT; int perf_cpu_time_max_percent_handler(struct ctl_table *table, int write, void __user *buffer, size_t *lenp, loff_t *ppos) { int ret = proc_dointvec(table, write, buffer, lenp, ppos); if (ret || !write) return ret; update_perf_cpu_limits(); return 0; } /* * perf samples are done in some very critical code paths (NMIs). * If they take too much CPU time, the system can lock up and not * get any real work done. This will drop the sample rate when * we detect that events are taking too long. */ #define NR_ACCUMULATED_SAMPLES 128 DEFINE_PER_CPU(u64, running_sample_length); void perf_sample_event_took(u64 sample_len_ns) { u64 avg_local_sample_len; u64 local_samples_len; if (atomic_read(&perf_sample_allowed_ns) == 0) return; /* decay the counter by 1 average sample */ local_samples_len = __get_cpu_var(running_sample_length); local_samples_len -= local_samples_len/NR_ACCUMULATED_SAMPLES; local_samples_len += sample_len_ns; __get_cpu_var(running_sample_length) = local_samples_len; /* * note: this will be biased artifically low until we have * seen NR_ACCUMULATED_SAMPLES. Doing it this way keeps us * from having to maintain a count. */ avg_local_sample_len = local_samples_len/NR_ACCUMULATED_SAMPLES; if (avg_local_sample_len <= atomic_read(&perf_sample_allowed_ns)) return; if (max_samples_per_tick <= 1) return; max_samples_per_tick = DIV_ROUND_UP(max_samples_per_tick, 2); sysctl_perf_event_sample_rate = max_samples_per_tick * HZ; perf_sample_period_ns = NSEC_PER_SEC / sysctl_perf_event_sample_rate; printk_ratelimited(KERN_WARNING "perf samples too long (%lld > %d), lowering " "kernel.perf_event_max_sample_rate to %d\n", avg_local_sample_len, atomic_read(&perf_sample_allowed_ns), sysctl_perf_event_sample_rate); update_perf_cpu_limits(); } static atomic64_t perf_event_id; static void cpu_ctx_sched_out(struct perf_cpu_context *cpuctx, enum event_type_t event_type); static void cpu_ctx_sched_in(struct perf_cpu_context *cpuctx, enum event_type_t event_type, struct task_struct *task); static void update_context_time(struct perf_event_context *ctx); static u64 perf_event_time(struct perf_event *event); void __weak perf_event_print_debug(void) { } extern __weak const char *perf_pmu_name(void) { return "pmu"; } static inline u64 perf_clock(void) { return local_clock(); } static inline struct perf_cpu_context * __get_cpu_context(struct perf_event_context *ctx) { return this_cpu_ptr(ctx->pmu->pmu_cpu_context); } static void perf_ctx_lock(struct perf_cpu_context *cpuctx, struct perf_event_context *ctx) { raw_spin_lock(&cpuctx->ctx.lock); if (ctx) raw_spin_lock(&ctx->lock); } static void perf_ctx_unlock(struct perf_cpu_context *cpuctx, struct perf_event_context *ctx) { if (ctx) raw_spin_unlock(&ctx->lock); raw_spin_unlock(&cpuctx->ctx.lock); } #ifdef CONFIG_CGROUP_PERF /* * perf_cgroup_info keeps track of time_enabled for a cgroup. * This is a per-cpu dynamically allocated data structure. */ struct perf_cgroup_info { u64 time; u64 timestamp; }; struct perf_cgroup { struct cgroup_subsys_state css; struct perf_cgroup_info __percpu *info; }; /* * Must ensure cgroup is pinned (css_get) before calling * this function. In other words, we cannot call this function * if there is no cgroup event for the current CPU context. */ static inline struct perf_cgroup * perf_cgroup_from_task(struct task_struct *task) { return container_of(task_subsys_state(task, perf_subsys_id), struct perf_cgroup, css); } static inline bool perf_cgroup_match(struct perf_event *event) { struct perf_event_context *ctx = event->ctx; struct perf_cpu_context *cpuctx = __get_cpu_context(ctx); /* @event doesn't care about cgroup */ if (!event->cgrp) return true; /* wants specific cgroup scope but @cpuctx isn't associated with any */ if (!cpuctx->cgrp) return false; /* * Cgroup scoping is recursive. An event enabled for a cgroup is * also enabled for all its descendant cgroups. If @cpuctx's * cgroup is a descendant of @event's (the test covers identity * case), it's a match. */ return cgroup_is_descendant(cpuctx->cgrp->css.cgroup, event->cgrp->css.cgroup); } static inline bool perf_tryget_cgroup(struct perf_event *event) { return css_tryget(&event->cgrp->css); } static inline void perf_put_cgroup(struct perf_event *event) { css_put(&event->cgrp->css); } static inline void perf_detach_cgroup(struct perf_event *event) { perf_put_cgroup(event); event->cgrp = NULL; } static inline int is_cgroup_event(struct perf_event *event) { return event->cgrp != NULL; } static inline u64 perf_cgroup_event_time(struct perf_event *event) { struct perf_cgroup_info *t; t = per_cpu_ptr(event->cgrp->info, event->cpu); return t->time; } static inline void __update_cgrp_time(struct perf_cgroup *cgrp) { struct perf_cgroup_info *info; u64 now; now = perf_clock(); info = this_cpu_ptr(cgrp->info); info->time += now - info->timestamp; info->timestamp = now; } static inline void update_cgrp_time_from_cpuctx(struct perf_cpu_context *cpuctx) { struct perf_cgroup *cgrp_out = cpuctx->cgrp; if (cgrp_out) __update_cgrp_time(cgrp_out); } static inline void update_cgrp_time_from_event(struct perf_event *event) { struct perf_cgroup *cgrp; /* * ensure we access cgroup data only when needed and * when we know the cgroup is pinned (css_get) */ if (!is_cgroup_event(event)) return; cgrp = perf_cgroup_from_task(current); /* * Do not update time when cgroup is not active */ if (cgrp == event->cgrp) __update_cgrp_time(event->cgrp); } static inline void perf_cgroup_set_timestamp(struct task_struct *task, struct perf_event_context *ctx) { struct perf_cgroup *cgrp; struct perf_cgroup_info *info; /* * ctx->lock held by caller * ensure we do not access cgroup data * unless we have the cgroup pinned (css_get) */ if (!task || !ctx->nr_cgroups) return; cgrp = perf_cgroup_from_task(task); info = this_cpu_ptr(cgrp->info); info->timestamp = ctx->timestamp; } #define PERF_CGROUP_SWOUT 0x1 /* cgroup switch out every event */ #define PERF_CGROUP_SWIN 0x2 /* cgroup switch in events based on task */ /* * reschedule events based on the cgroup constraint of task. * * mode SWOUT : schedule out everything * mode SWIN : schedule in based on cgroup for next */ void perf_cgroup_switch(struct task_struct *task, int mode) { struct perf_cpu_context *cpuctx; struct pmu *pmu; unsigned long flags; /* * disable interrupts to avoid geting nr_cgroup * changes via __perf_event_disable(). Also * avoids preemption. */ local_irq_save(flags); /* * we reschedule only in the presence of cgroup * constrained events. */ rcu_read_lock(); list_for_each_entry_rcu(pmu, &pmus, entry) { cpuctx = this_cpu_ptr(pmu->pmu_cpu_context); if (cpuctx->unique_pmu != pmu) continue; /* ensure we process each cpuctx once */ /* * perf_cgroup_events says at least one * context on this CPU has cgroup events. * * ctx->nr_cgroups reports the number of cgroup * events for a context. */ if (cpuctx->ctx.nr_cgroups > 0) { perf_ctx_lock(cpuctx, cpuctx->task_ctx); perf_pmu_disable(cpuctx->ctx.pmu); if (mode & PERF_CGROUP_SWOUT) { cpu_ctx_sched_out(cpuctx, EVENT_ALL); /* * must not be done before ctxswout due * to event_filter_match() in event_sched_out() */ cpuctx->cgrp = NULL; } if (mode & PERF_CGROUP_SWIN) { WARN_ON_ONCE(cpuctx->cgrp); /* * set cgrp before ctxsw in to allow * event_filter_match() to not have to pass * task around */ cpuctx->cgrp = perf_cgroup_from_task(task); cpu_ctx_sched_in(cpuctx, EVENT_ALL, task); } perf_pmu_enable(cpuctx->ctx.pmu); perf_ctx_unlock(cpuctx, cpuctx->task_ctx); } } rcu_read_unlock(); local_irq_restore(flags); } static inline void perf_cgroup_sched_out(struct task_struct *task, struct task_struct *next) { struct perf_cgroup *cgrp1; struct perf_cgroup *cgrp2 = NULL; /* * we come here when we know perf_cgroup_events > 0 */ cgrp1 = perf_cgroup_from_task(task); /* * next is NULL when called from perf_event_enable_on_exec() * that will systematically cause a cgroup_switch() */ if (next) cgrp2 = perf_cgroup_from_task(next); /* * only schedule out current cgroup events if we know * that we are switching to a different cgroup. Otherwise, * do no touch the cgroup events. */ if (cgrp1 != cgrp2) perf_cgroup_switch(task, PERF_CGROUP_SWOUT); } static inline void perf_cgroup_sched_in(struct task_struct *prev, struct task_struct *task) { struct perf_cgroup *cgrp1; struct perf_cgroup *cgrp2 = NULL; /* * we come here when we know perf_cgroup_events > 0 */ cgrp1 = perf_cgroup_from_task(task); /* prev can never be NULL */ cgrp2 = perf_cgroup_from_task(prev); /* * only need to schedule in cgroup events if we are changing * cgroup during ctxsw. Cgroup events were not scheduled * out of ctxsw out if that was not the case. */ if (cgrp1 != cgrp2) perf_cgroup_switch(task, PERF_CGROUP_SWIN); } static inline int perf_cgroup_connect(int fd, struct perf_event *event, struct perf_event_attr *attr, struct perf_event *group_leader) { struct perf_cgroup *cgrp; struct cgroup_subsys_state *css; struct fd f = fdget(fd); int ret = 0; if (!f.file) return -EBADF; css = cgroup_css_from_dir(f.file, perf_subsys_id); if (IS_ERR(css)) { ret = PTR_ERR(css); goto out; } cgrp = container_of(css, struct perf_cgroup, css); event->cgrp = cgrp; /* must be done before we fput() the file */ if (!perf_tryget_cgroup(event)) { event->cgrp = NULL; ret = -ENOENT; goto out; } /* * all events in a group must monitor * the same cgroup because a task belongs * to only one perf cgroup at a time */ if (group_leader && group_leader->cgrp != cgrp) { perf_detach_cgroup(event); ret = -EINVAL; } out: fdput(f); return ret; } static inline void perf_cgroup_set_shadow_time(struct perf_event *event, u64 now) { struct perf_cgroup_info *t; t = per_cpu_ptr(event->cgrp->info, event->cpu); event->shadow_ctx_time = now - t->timestamp; } static inline void perf_cgroup_defer_enabled(struct perf_event *event) { /* * when the current task's perf cgroup does not match * the event's, we need to remember to call the * perf_mark_enable() function the first time a task with * a matching perf cgroup is scheduled in. */ if (is_cgroup_event(event) && !perf_cgroup_match(event)) event->cgrp_defer_enabled = 1; } static inline void perf_cgroup_mark_enabled(struct perf_event *event, struct perf_event_context *ctx) { struct perf_event *sub; u64 tstamp = perf_event_time(event); if (!event->cgrp_defer_enabled) return; event->cgrp_defer_enabled = 0; event->tstamp_enabled = tstamp - event->total_time_enabled; list_for_each_entry(sub, &event->sibling_list, group_entry) { if (sub->state >= PERF_EVENT_STATE_INACTIVE) { sub->tstamp_enabled = tstamp - sub->total_time_enabled; sub->cgrp_defer_enabled = 0; } } } #else /* !CONFIG_CGROUP_PERF */ static inline bool perf_cgroup_match(struct perf_event *event) { return true; } static inline void perf_detach_cgroup(struct perf_event *event) {} static inline int is_cgroup_event(struct perf_event *event) { return 0; } static inline u64 perf_cgroup_event_cgrp_time(struct perf_event *event) { return 0; } static inline void update_cgrp_time_from_event(struct perf_event *event) { } static inline void update_cgrp_time_from_cpuctx(struct perf_cpu_context *cpuctx) { } static inline void perf_cgroup_sched_out(struct task_struct *task, struct task_struct *next) { } static inline void perf_cgroup_sched_in(struct task_struct *prev, struct task_struct *task) { } static inline int perf_cgroup_connect(pid_t pid, struct perf_event *event, struct perf_event_attr *attr, struct perf_event *group_leader) { return -EINVAL; } static inline void perf_cgroup_set_timestamp(struct task_struct *task, struct perf_event_context *ctx) { } void perf_cgroup_switch(struct task_struct *task, struct task_struct *next) { } static inline void perf_cgroup_set_shadow_time(struct perf_event *event, u64 now) { } static inline u64 perf_cgroup_event_time(struct perf_event *event) { return 0; } static inline void perf_cgroup_defer_enabled(struct perf_event *event) { } static inline void perf_cgroup_mark_enabled(struct perf_event *event, struct perf_event_context *ctx) { } #endif void perf_pmu_disable(struct pmu *pmu) { int *count = this_cpu_ptr(pmu->pmu_disable_count); if (!(*count)++) pmu->pmu_disable(pmu); } void perf_pmu_enable(struct pmu *pmu) { int *count = this_cpu_ptr(pmu->pmu_disable_count); if (!--(*count)) pmu->pmu_enable(pmu); } static DEFINE_PER_CPU(struct list_head, rotation_list); /* * perf_pmu_rotate_start() and perf_rotate_context() are fully serialized * because they're strictly cpu affine and rotate_start is called with IRQs * disabled, while rotate_context is called from IRQ context. */ static void perf_pmu_rotate_start(struct pmu *pmu) { struct perf_cpu_context *cpuctx = this_cpu_ptr(pmu->pmu_cpu_context); struct list_head *head = &__get_cpu_var(rotation_list); WARN_ON(!irqs_disabled()); if (list_empty(&cpuctx->rotation_list)) { int was_empty = list_empty(head); list_add(&cpuctx->rotation_list, head); if (was_empty) tick_nohz_full_kick(); } } static void get_ctx(struct perf_event_context *ctx) { WARN_ON(!atomic_inc_not_zero(&ctx->refcount)); } static void put_ctx(struct perf_event_context *ctx) { if (atomic_dec_and_test(&ctx->refcount)) { if (ctx->parent_ctx) put_ctx(ctx->parent_ctx); if (ctx->task) put_task_struct(ctx->task); kfree_rcu(ctx, rcu_head); } } static void unclone_ctx(struct perf_event_context *ctx) { if (ctx->parent_ctx) { put_ctx(ctx->parent_ctx); ctx->parent_ctx = NULL; } } static u32 perf_event_pid(struct perf_event *event, struct task_struct *p) { /* * only top level events have the pid namespace they were created in */ if (event->parent) event = event->parent; return task_tgid_nr_ns(p, event->ns); } static u32 perf_event_tid(struct perf_event *event, struct task_struct *p) { /* * only top level events have the pid namespace they were created in */ if (event->parent) event = event->parent; return task_pid_nr_ns(p, event->ns); } /* * If we inherit events we want to return the parent event id * to userspace. */ static u64 primary_event_id(struct perf_event *event) { u64 id = event->id; if (event->parent) id = event->parent->id; return id; } /* * Get the perf_event_context for a task and lock it. * This has to cope with with the fact that until it is locked, * the context could get moved to another task. */ static struct perf_event_context * perf_lock_task_context(struct task_struct *task, int ctxn, unsigned long *flags) { struct perf_event_context *ctx; retry: /* * One of the few rules of preemptible RCU is that one cannot do * rcu_read_unlock() while holding a scheduler (or nested) lock when * part of the read side critical section was preemptible -- see * rcu_read_unlock_special(). * * Since ctx->lock nests under rq->lock we must ensure the entire read * side critical section is non-preemptible. */ preempt_disable(); rcu_read_lock(); ctx = rcu_dereference(task->perf_event_ctxp[ctxn]); if (ctx) { /* * If this context is a clone of another, it might * get swapped for another underneath us by * perf_event_task_sched_out, though the * rcu_read_lock() protects us from any context * getting freed. Lock the context and check if it * got swapped before we could get the lock, and retry * if so. If we locked the right context, then it * can't get swapped on us any more. */ raw_spin_lock_irqsave(&ctx->lock, *flags); if (ctx != rcu_dereference(task->perf_event_ctxp[ctxn])) { raw_spin_unlock_irqrestore(&ctx->lock, *flags); rcu_read_unlock(); preempt_enable(); goto retry; } if (!atomic_inc_not_zero(&ctx->refcount)) { raw_spin_unlock_irqrestore(&ctx->lock, *flags); ctx = NULL; } } rcu_read_unlock(); preempt_enable(); return ctx; } /* * Get the context for a task and increment its pin_count so it * can't get swapped to another task. This also increments its * reference count so that the context can't get freed. */ static struct perf_event_context * perf_pin_task_context(struct task_struct *task, int ctxn) { struct perf_event_context *ctx; unsigned long flags; ctx = perf_lock_task_context(task, ctxn, &flags); if (ctx) { ++ctx->pin_count; raw_spin_unlock_irqrestore(&ctx->lock, flags); } return ctx; } static void perf_unpin_context(struct perf_event_context *ctx) { unsigned long flags; raw_spin_lock_irqsave(&ctx->lock, flags); --ctx->pin_count; raw_spin_unlock_irqrestore(&ctx->lock, flags); } /* * Update the record of the current time in a context. */ static void update_context_time(struct perf_event_context *ctx) { u64 now = perf_clock(); ctx->time += now - ctx->timestamp; ctx->timestamp = now; } static u64 perf_event_time(struct perf_event *event) { struct perf_event_context *ctx = event->ctx; if (is_cgroup_event(event)) return perf_cgroup_event_time(event); return ctx ? ctx->time : 0; } /* * Update the total_time_enabled and total_time_running fields for a event. * The caller of this function needs to hold the ctx->lock. */ static void update_event_times(struct perf_event *event) { struct perf_event_context *ctx = event->ctx; u64 run_end; if (event->state < PERF_EVENT_STATE_INACTIVE || event->group_leader->state < PERF_EVENT_STATE_INACTIVE) return; /* * in cgroup mode, time_enabled represents * the time the event was enabled AND active * tasks were in the monitored cgroup. This is * independent of the activity of the context as * there may be a mix of cgroup and non-cgroup events. * * That is why we treat cgroup events differently * here. */ if (is_cgroup_event(event)) run_end = perf_cgroup_event_time(event); else if (ctx->is_active) run_end = ctx->time; else run_end = event->tstamp_stopped; event->total_time_enabled = run_end - event->tstamp_enabled; if (event->state == PERF_EVENT_STATE_INACTIVE) run_end = event->tstamp_stopped; else run_end = perf_event_time(event); event->total_time_running = run_end - event->tstamp_running; } /* * Update total_time_enabled and total_time_running for all events in a group. */ static void update_group_times(struct perf_event *leader) { struct perf_event *event; update_event_times(leader); list_for_each_entry(event, &leader->sibling_list, group_entry) update_event_times(event); } static struct list_head * ctx_group_list(struct perf_event *event, struct perf_event_context *ctx) { if (event->attr.pinned) return &ctx->pinned_groups; else return &ctx->flexible_groups; } /* * Add a event from the lists for its context. * Must be called with ctx->mutex and ctx->lock held. */ static void list_add_event(struct perf_event *event, struct perf_event_context *ctx) { WARN_ON_ONCE(event->attach_state & PERF_ATTACH_CONTEXT); event->attach_state |= PERF_ATTACH_CONTEXT; /* * If we're a stand alone event or group leader, we go to the context * list, group events are kept attached to the group so that * perf_group_detach can, at all times, locate all siblings. */ if (event->group_leader == event) { struct list_head *list; if (is_software_event(event)) event->group_flags |= PERF_GROUP_SOFTWARE; list = ctx_group_list(event, ctx); list_add_tail(&event->group_entry, list); } if (is_cgroup_event(event)) ctx->nr_cgroups++; if (has_branch_stack(event)) ctx->nr_branch_stack++; list_add_rcu(&event->event_entry, &ctx->event_list); if (!ctx->nr_events) perf_pmu_rotate_start(ctx->pmu); ctx->nr_events++; if (event->attr.inherit_stat) ctx->nr_stat++; } /* * Initialize event state based on the perf_event_attr::disabled. */ static inline void perf_event__state_init(struct perf_event *event) { event->state = event->attr.disabled ? PERF_EVENT_STATE_OFF : PERF_EVENT_STATE_INACTIVE; } /* * Called at perf_event creation and when events are attached/detached from a * group. */ static void perf_event__read_size(struct perf_event *event) { int entry = sizeof(u64); /* value */ int size = 0; int nr = 1; if (event->attr.read_format & PERF_FORMAT_TOTAL_TIME_ENABLED) size += sizeof(u64); if (event->attr.read_format & PERF_FORMAT_TOTAL_TIME_RUNNING) size += sizeof(u64); if (event->attr.read_format & PERF_FORMAT_ID) entry += sizeof(u64); if (event->attr.read_format & PERF_FORMAT_GROUP) { nr += event->group_leader->nr_siblings; size += sizeof(u64); } size += entry * nr; event->read_size = size; } static void perf_event__header_size(struct perf_event *event) { struct perf_sample_data *data; u64 sample_type = event->attr.sample_type; u16 size = 0; perf_event__read_size(event); if (sample_type & PERF_SAMPLE_IP) size += sizeof(data->ip); if (sample_type & PERF_SAMPLE_ADDR) size += sizeof(data->addr); if (sample_type & PERF_SAMPLE_PERIOD) size += sizeof(data->period); if (sample_type & PERF_SAMPLE_WEIGHT) size += sizeof(data->weight); if (sample_type & PERF_SAMPLE_READ) size += event->read_size; if (sample_type & PERF_SAMPLE_DATA_SRC) size += sizeof(data->data_src.val); event->header_size = size; } static void perf_event__id_header_size(struct perf_event *event) { struct perf_sample_data *data; u64 sample_type = event->attr.sample_type; u16 size = 0; if (sample_type & PERF_SAMPLE_TID) size += sizeof(data->tid_entry); if (sample_type & PERF_SAMPLE_TIME) size += sizeof(data->time); if (sample_type & PERF_SAMPLE_ID) size += sizeof(data->id); if (sample_type & PERF_SAMPLE_STREAM_ID) size += sizeof(data->stream_id); if (sample_type & PERF_SAMPLE_CPU) size += sizeof(data->cpu_entry); event->id_header_size = size; } static void perf_group_attach(struct perf_event *event) { struct perf_event *group_leader = event->group_leader, *pos; /* * We can have double attach due to group movement in perf_event_open. */ if (event->attach_state & PERF_ATTACH_GROUP) return; event->attach_state |= PERF_ATTACH_GROUP; if (group_leader == event) return; if (group_leader->group_flags & PERF_GROUP_SOFTWARE && !is_software_event(event)) group_leader->group_flags &= ~PERF_GROUP_SOFTWARE; list_add_tail(&event->group_entry, &group_leader->sibling_list); group_leader->nr_siblings++; perf_event__header_size(group_leader); list_for_each_entry(pos, &group_leader->sibling_list, group_entry) perf_event__header_size(pos); } /* * Remove a event from the lists for its context. * Must be called with ctx->mutex and ctx->lock held. */ static void list_del_event(struct perf_event *event, struct perf_event_context *ctx) { struct perf_cpu_context *cpuctx; /* * We can have double detach due to exit/hot-unplug + close. */ if (!(event->attach_state & PERF_ATTACH_CONTEXT)) return; event->attach_state &= ~PERF_ATTACH_CONTEXT; if (is_cgroup_event(event)) { ctx->nr_cgroups--; cpuctx = __get_cpu_context(ctx); /* * if there are no more cgroup events * then cler cgrp to avoid stale pointer * in update_cgrp_time_from_cpuctx() */ if (!ctx->nr_cgroups) cpuctx->cgrp = NULL; } if (has_branch_stack(event)) ctx->nr_branch_stack--; ctx->nr_events--; if (event->attr.inherit_stat) ctx->nr_stat--; list_del_rcu(&event->event_entry); if (event->group_leader == event) list_del_init(&event->group_entry); update_group_times(event); /* * If event was in error state, then keep it * that way, otherwise bogus counts will be * returned on read(). The only way to get out * of error state is by explicit re-enabling * of the event */ if (event->state > PERF_EVENT_STATE_OFF) event->state = PERF_EVENT_STATE_OFF; } static void perf_group_detach(struct perf_event *event) { struct perf_event *sibling, *tmp; struct list_head *list = NULL; /* * We can have double detach due to exit/hot-unplug + close. */ if (!(event->attach_state & PERF_ATTACH_GROUP)) return; event->attach_state &= ~PERF_ATTACH_GROUP; /* * If this is a sibling, remove it from its group. */ if (event->group_leader != event) { list_del_init(&event->group_entry); event->group_leader->nr_siblings--; goto out; } if (!list_empty(&event->group_entry)) list = &event->group_entry; /* * If this was a group event with sibling events then * upgrade the siblings to singleton events by adding them * to whatever list we are on. */ list_for_each_entry_safe(sibling, tmp, &event->sibling_list, group_entry) { if (list) list_move_tail(&sibling->group_entry, list); sibling->group_leader = sibling; /* Inherit group flags from the previous leader */ sibling->group_flags = event->group_flags; } out: perf_event__header_size(event->group_leader); list_for_each_entry(tmp, &event->group_leader->sibling_list, group_entry) perf_event__header_size(tmp); } static inline int event_filter_match(struct perf_event *event) { return (event->cpu == -1 || event->cpu == smp_processor_id()) && perf_cgroup_match(event); } static void event_sched_out(struct perf_event *event, struct perf_cpu_context *cpuctx, struct perf_event_context *ctx) { u64 tstamp = perf_event_time(event); u64 delta; /* * An event which could not be activated because of * filter mismatch still needs to have its timings * maintained, otherwise bogus information is return * via read() for time_enabled, time_running: */ if (event->state == PERF_EVENT_STATE_INACTIVE && !event_filter_match(event)) { delta = tstamp - event->tstamp_stopped; event->tstamp_running += delta; event->tstamp_stopped = tstamp; } if (event->state != PERF_EVENT_STATE_ACTIVE) return; event->state = PERF_EVENT_STATE_INACTIVE; if (event->pending_disable) { event->pending_disable = 0; event->state = PERF_EVENT_STATE_OFF; } event->tstamp_stopped = tstamp; event->pmu->del(event, 0); event->oncpu = -1; if (!is_software_event(event)) cpuctx->active_oncpu--; ctx->nr_active--; if (event->attr.freq && event->attr.sample_freq) ctx->nr_freq--; if (event->attr.exclusive || !cpuctx->active_oncpu) cpuctx->exclusive = 0; } static void group_sched_out(struct perf_event *group_event, struct perf_cpu_context *cpuctx, struct perf_event_context *ctx) { struct perf_event *event; int state = group_event->state; event_sched_out(group_event, cpuctx, ctx); /* * Schedule out siblings (if any): */ list_for_each_entry(event, &group_event->sibling_list, group_entry) event_sched_out(event, cpuctx, ctx); if (state == PERF_EVENT_STATE_ACTIVE && group_event->attr.exclusive) cpuctx->exclusive = 0; } struct remove_event { struct perf_event *event; bool detach_group; }; /* * Cross CPU call to remove a performance event * * We disable the event on the hardware level first. After that we * remove it from the context list. */ static int __perf_remove_from_context(void *info) { struct remove_event *re = info; struct perf_event *event = re->event; struct perf_event_context *ctx = event->ctx; struct perf_cpu_context *cpuctx = __get_cpu_context(ctx); raw_spin_lock(&ctx->lock); event_sched_out(event, cpuctx, ctx); if (re->detach_group) perf_group_detach(event); list_del_event(event, ctx); if (!ctx->nr_events && cpuctx->task_ctx == ctx) { ctx->is_active = 0; cpuctx->task_ctx = NULL; } raw_spin_unlock(&ctx->lock); return 0; } /* * Remove the event from a task's (or a CPU's) list of events. * * CPU events are removed with a smp call. For task events we only * call when the task is on a CPU. * * If event->ctx is a cloned context, callers must make sure that * every task struct that event->ctx->task could possibly point to * remains valid. This is OK when called from perf_release since * that only calls us on the top-level context, which can't be a clone. * When called from perf_event_exit_task, it's OK because the * context has been detached from its task. */ static void perf_remove_from_context(struct perf_event *event, bool detach_group) { struct perf_event_context *ctx = event->ctx; struct task_struct *task = ctx->task; struct remove_event re = { .event = event, .detach_group = detach_group, }; lockdep_assert_held(&ctx->mutex); if (!task) { /* * Per cpu events are removed via an smp call and * the removal is always successful. */ cpu_function_call(event->cpu, __perf_remove_from_context, &re); return; } retry: if (!task_function_call(task, __perf_remove_from_context, &re)) return; raw_spin_lock_irq(&ctx->lock); /* * If we failed to find a running task, but find the context active now * that we've acquired the ctx->lock, retry. */ if (ctx->is_active) { raw_spin_unlock_irq(&ctx->lock); /* * Reload the task pointer, it might have been changed by * a concurrent perf_event_context_sched_out(). */ task = ctx->task; goto retry; } /* * Since the task isn't running, its safe to remove the event, us * holding the ctx->lock ensures the task won't get scheduled in. */ if (detach_group) perf_group_detach(event); list_del_event(event, ctx); raw_spin_unlock_irq(&ctx->lock); } /* * Cross CPU call to disable a performance event */ int __perf_event_disable(void *info) { struct perf_event *event = info; struct perf_event_context *ctx = event->ctx; struct perf_cpu_context *cpuctx = __get_cpu_context(ctx); /* * If this is a per-task event, need to check whether this * event's task is the current task on this cpu. * * Can trigger due to concurrent perf_event_context_sched_out() * flipping contexts around. */ if (ctx->task && cpuctx->task_ctx != ctx) return -EINVAL; raw_spin_lock(&ctx->lock); /* * If the event is on, turn it off. * If it is in error state, leave it in error state. */ if (event->state >= PERF_EVENT_STATE_INACTIVE) { update_context_time(ctx); update_cgrp_time_from_event(event); update_group_times(event); if (event == event->group_leader) group_sched_out(event, cpuctx, ctx); else event_sched_out(event, cpuctx, ctx); event->state = PERF_EVENT_STATE_OFF; } raw_spin_unlock(&ctx->lock); return 0; } /* * Disable a event. * * If event->ctx is a cloned context, callers must make sure that * every task struct that event->ctx->task could possibly point to * remains valid. This condition is satisifed when called through * perf_event_for_each_child or perf_event_for_each because they * hold the top-level event's child_mutex, so any descendant that * goes to exit will block in sync_child_event. * When called from perf_pending_event it's OK because event->ctx * is the current context on this CPU and preemption is disabled, * hence we can't get into perf_event_task_sched_out for this context. */ void perf_event_disable(struct perf_event *event) { struct perf_event_context *ctx = event->ctx; struct task_struct *task = ctx->task; if (!task) { /* * Disable the event on the cpu that it's on */ cpu_function_call(event->cpu, __perf_event_disable, event); return; } retry: if (!task_function_call(task, __perf_event_disable, event)) return; raw_spin_lock_irq(&ctx->lock); /* * If the event is still active, we need to retry the cross-call. */ if (event->state == PERF_EVENT_STATE_ACTIVE) { raw_spin_unlock_irq(&ctx->lock); /* * Reload the task pointer, it might have been changed by * a concurrent perf_event_context_sched_out(). */ task = ctx->task; goto retry; } /* * Since we have the lock this context can't be scheduled * in, so we can change the state safely. */ if (event->state == PERF_EVENT_STATE_INACTIVE) { update_group_times(event); event->state = PERF_EVENT_STATE_OFF; } raw_spin_unlock_irq(&ctx->lock); } EXPORT_SYMBOL_GPL(perf_event_disable); static void perf_set_shadow_time(struct perf_event *event, struct perf_event_context *ctx, u64 tstamp) { /* * use the correct time source for the time snapshot * * We could get by without this by leveraging the * fact that to get to this function, the caller * has most likely already called update_context_time() * and update_cgrp_time_xx() and thus both timestamp * are identical (or very close). Given that tstamp is, * already adjusted for cgroup, we could say that: * tstamp - ctx->timestamp * is equivalent to * tstamp - cgrp->timestamp. * * Then, in perf_output_read(), the calculation would * work with no changes because: * - event is guaranteed scheduled in * - no scheduled out in between * - thus the timestamp would be the same * * But this is a bit hairy. * * So instead, we have an explicit cgroup call to remain * within the time time source all along. We believe it * is cleaner and simpler to understand. */ if (is_cgroup_event(event)) perf_cgroup_set_shadow_time(event, tstamp); else event->shadow_ctx_time = tstamp - ctx->timestamp; } #define MAX_INTERRUPTS (~0ULL) static void perf_log_throttle(struct perf_event *event, int enable); static int event_sched_in(struct perf_event *event, struct perf_cpu_context *cpuctx, struct perf_event_context *ctx) { u64 tstamp = perf_event_time(event); if (event->state <= PERF_EVENT_STATE_OFF) return 0; event->state = PERF_EVENT_STATE_ACTIVE; event->oncpu = smp_processor_id(); /* * Unthrottle events, since we scheduled we might have missed several * ticks already, also for a heavily scheduling task there is little * guarantee it'll get a tick in a timely manner. */ if (unlikely(event->hw.interrupts == MAX_INTERRUPTS)) { perf_log_throttle(event, 1); event->hw.interrupts = 0; } /* * The new state must be visible before we turn it on in the hardware: */ smp_wmb(); if (event->pmu->add(event, PERF_EF_START)) { event->state = PERF_EVENT_STATE_INACTIVE; event->oncpu = -1; return -EAGAIN; } event->tstamp_running += tstamp - event->tstamp_stopped; perf_set_shadow_time(event, ctx, tstamp); if (!is_software_event(event)) cpuctx->active_oncpu++; ctx->nr_active++; if (event->attr.freq && event->attr.sample_freq) ctx->nr_freq++; if (event->attr.exclusive) cpuctx->exclusive = 1; return 0; } static int group_sched_in(struct perf_event *group_event, struct perf_cpu_context *cpuctx, struct perf_event_context *ctx) { struct perf_event *event, *partial_group = NULL; struct pmu *pmu = group_event->pmu; u64 now = ctx->time; bool simulate = false; if (group_event->state == PERF_EVENT_STATE_OFF) return 0; pmu->start_txn(pmu); if (event_sched_in(group_event, cpuctx, ctx)) { pmu->cancel_txn(pmu); return -EAGAIN; } /* * Schedule in siblings as one group (if any): */ list_for_each_entry(event, &group_event->sibling_list, group_entry) { if (event_sched_in(event, cpuctx, ctx)) { partial_group = event; goto group_error; } } if (!pmu->commit_txn(pmu)) return 0; group_error: /* * Groups can be scheduled in as one unit only, so undo any * partial group before returning: * The events up to the failed event are scheduled out normally, * tstamp_stopped will be updated. * * The failed events and the remaining siblings need to have * their timings updated as if they had gone thru event_sched_in() * and event_sched_out(). This is required to get consistent timings * across the group. This also takes care of the case where the group * could never be scheduled by ensuring tstamp_stopped is set to mark * the time the event was actually stopped, such that time delta * calculation in update_event_times() is correct. */ list_for_each_entry(event, &group_event->sibling_list, group_entry) { if (event == partial_group) simulate = true; if (simulate) { event->tstamp_running += now - event->tstamp_stopped; event->tstamp_stopped = now; } else { event_sched_out(event, cpuctx, ctx); } } event_sched_out(group_event, cpuctx, ctx); pmu->cancel_txn(pmu); return -EAGAIN; } /* * Work out whether we can put this event group on the CPU now. */ static int group_can_go_on(struct perf_event *event, struct perf_cpu_context *cpuctx, int can_add_hw) { /* * Groups consisting entirely of software events can always go on. */ if (event->group_flags & PERF_GROUP_SOFTWARE) return 1; /* * If an exclusive group is already on, no other hardware * events can go on. */ if (cpuctx->exclusive) return 0; /* * If this group is exclusive and there are already * events on the CPU, it can't go on. */ if (event->attr.exclusive && cpuctx->active_oncpu) return 0; /* * Otherwise, try to add it if all previous groups were able * to go on. */ return can_add_hw; } static void add_event_to_ctx(struct perf_event *event, struct perf_event_context *ctx) { u64 tstamp = perf_event_time(event); list_add_event(event, ctx); perf_group_attach(event); event->tstamp_enabled = tstamp; event->tstamp_running = tstamp; event->tstamp_stopped = tstamp; } static void task_ctx_sched_out(struct perf_event_context *ctx); static void ctx_sched_in(struct perf_event_context *ctx, struct perf_cpu_context *cpuctx, enum event_type_t event_type, struct task_struct *task); static void perf_event_sched_in(struct perf_cpu_context *cpuctx, struct perf_event_context *ctx, struct task_struct *task) { cpu_ctx_sched_in(cpuctx, EVENT_PINNED, task); if (ctx) ctx_sched_in(ctx, cpuctx, EVENT_PINNED, task); cpu_ctx_sched_in(cpuctx, EVENT_FLEXIBLE, task); if (ctx) ctx_sched_in(ctx, cpuctx, EVENT_FLEXIBLE, task); } /* * Cross CPU call to install and enable a performance event * * Must be called with ctx->mutex held */ static int __perf_install_in_context(void *info) { struct perf_event *event = info; struct perf_event_context *ctx = event->ctx; struct perf_cpu_context *cpuctx = __get_cpu_context(ctx); struct perf_event_context *task_ctx = cpuctx->task_ctx; struct task_struct *task = current; perf_ctx_lock(cpuctx, task_ctx); perf_pmu_disable(cpuctx->ctx.pmu); /* * If there was an active task_ctx schedule it out. */ if (task_ctx) task_ctx_sched_out(task_ctx); /* * If the context we're installing events in is not the * active task_ctx, flip them. */ if (ctx->task && task_ctx != ctx) { if (task_ctx) raw_spin_unlock(&task_ctx->lock); raw_spin_lock(&ctx->lock); task_ctx = ctx; } if (task_ctx) { cpuctx->task_ctx = task_ctx; task = task_ctx->task; } cpu_ctx_sched_out(cpuctx, EVENT_ALL); update_context_time(ctx); /* * update cgrp time only if current cgrp * matches event->cgrp. Must be done before * calling add_event_to_ctx() */ update_cgrp_time_from_event(event); add_event_to_ctx(event, ctx); /* * Schedule everything back in */ perf_event_sched_in(cpuctx, task_ctx, task); perf_pmu_enable(cpuctx->ctx.pmu); perf_ctx_unlock(cpuctx, task_ctx); return 0; } /* * Attach a performance event to a context * * First we add the event to the list with the hardware enable bit * in event->hw_config cleared. * * If the event is attached to a task which is on a CPU we use a smp * call to enable it in the task context. The task might have been * scheduled away, but we check this in the smp call again. */ static void perf_install_in_context(struct perf_event_context *ctx, struct perf_event *event, int cpu) { struct task_struct *task = ctx->task; lockdep_assert_held(&ctx->mutex); event->ctx = ctx; if (event->cpu != -1) event->cpu = cpu; if (!task) { /* * Per cpu events are installed via an smp call and * the install is always successful. */ cpu_function_call(cpu, __perf_install_in_context, event); return; } retry: if (!task_function_call(task, __perf_install_in_context, event)) return; raw_spin_lock_irq(&ctx->lock); /* * If we failed to find a running task, but find the context active now * that we've acquired the ctx->lock, retry. */ if (ctx->is_active) { raw_spin_unlock_irq(&ctx->lock); /* * Reload the task pointer, it might have been changed by * a concurrent perf_event_context_sched_out(). */ task = ctx->task; goto retry; } /* * Since the task isn't running, its safe to add the event, us holding * the ctx->lock ensures the task won't get scheduled in. */ add_event_to_ctx(event, ctx); raw_spin_unlock_irq(&ctx->lock); } /* * Put a event into inactive state and update time fields. * Enabling the leader of a group effectively enables all * the group members that aren't explicitly disabled, so we * have to update their ->tstamp_enabled also. * Note: this works for group members as well as group leaders * since the non-leader members' sibling_lists will be empty. */ static void __perf_event_mark_enabled(struct perf_event *event) { struct perf_event *sub; u64 tstamp = perf_event_time(event); event->state = PERF_EVENT_STATE_INACTIVE; event->tstamp_enabled = tstamp - event->total_time_enabled; list_for_each_entry(sub, &event->sibling_list, group_entry) { if (sub->state >= PERF_EVENT_STATE_INACTIVE) sub->tstamp_enabled = tstamp - sub->total_time_enabled; } } /* * Cross CPU call to enable a performance event */ static int __perf_event_enable(void *info) { struct perf_event *event = info; struct perf_event_context *ctx = event->ctx; struct perf_event *leader = event->group_leader; struct perf_cpu_context *cpuctx = __get_cpu_context(ctx); int err; /* * There's a time window between 'ctx->is_active' check * in perf_event_enable function and this place having: * - IRQs on * - ctx->lock unlocked * * where the task could be killed and 'ctx' deactivated * by perf_event_exit_task. */ if (!ctx->is_active) return -EINVAL; raw_spin_lock(&ctx->lock); update_context_time(ctx); if (event->state >= PERF_EVENT_STATE_INACTIVE) goto unlock; /* * set current task's cgroup time reference point */ perf_cgroup_set_timestamp(current, ctx); __perf_event_mark_enabled(event); if (!event_filter_match(event)) { if (is_cgroup_event(event)) perf_cgroup_defer_enabled(event); goto unlock; } /* * If the event is in a group and isn't the group leader, * then don't put it on unless the group is on. */ if (leader != event && leader->state != PERF_EVENT_STATE_ACTIVE) goto unlock; if (!group_can_go_on(event, cpuctx, 1)) { err = -EEXIST; } else { if (event == leader) err = group_sched_in(event, cpuctx, ctx); else err = event_sched_in(event, cpuctx, ctx); } if (err) { /* * If this event can't go on and it's part of a * group, then the whole group has to come off. */ if (leader != event) group_sched_out(leader, cpuctx, ctx); if (leader->attr.pinned) { update_group_times(leader); leader->state = PERF_EVENT_STATE_ERROR; } } unlock: raw_spin_unlock(&ctx->lock); return 0; } /* * Enable a event. * * If event->ctx is a cloned context, callers must make sure that * every task struct that event->ctx->task could possibly point to * remains valid. This condition is satisfied when called through * perf_event_for_each_child or perf_event_for_each as described * for perf_event_disable. */ void perf_event_enable(struct perf_event *event) { struct perf_event_context *ctx = event->ctx; struct task_struct *task = ctx->task; if (!task) { /* * Enable the event on the cpu that it's on */ cpu_function_call(event->cpu, __perf_event_enable, event); return; } raw_spin_lock_irq(&ctx->lock); if (event->state >= PERF_EVENT_STATE_INACTIVE) goto out; /* * If the event is in error state, clear that first. * That way, if we see the event in error state below, we * know that it has gone back into error state, as distinct * from the task having been scheduled away before the * cross-call arrived. */ if (event->state == PERF_EVENT_STATE_ERROR) event->state = PERF_EVENT_STATE_OFF; retry: if (!ctx->is_active) { __perf_event_mark_enabled(event); goto out; } raw_spin_unlock_irq(&ctx->lock); if (!task_function_call(task, __perf_event_enable, event)) return; raw_spin_lock_irq(&ctx->lock); /* * If the context is active and the event is still off, * we need to retry the cross-call. */ if (ctx->is_active && event->state == PERF_EVENT_STATE_OFF) { /* * task could have been flipped by a concurrent * perf_event_context_sched_out() */ task = ctx->task; goto retry; } out: raw_spin_unlock_irq(&ctx->lock); } EXPORT_SYMBOL_GPL(perf_event_enable); int perf_event_refresh(struct perf_event *event, int refresh) { /* * not supported on inherited events */ if (event->attr.inherit || !is_sampling_event(event)) return -EINVAL; atomic_add(refresh, &event->event_limit); perf_event_enable(event); return 0; } EXPORT_SYMBOL_GPL(perf_event_refresh); static void ctx_sched_out(struct perf_event_context *ctx, struct perf_cpu_context *cpuctx, enum event_type_t event_type) { struct perf_event *event; int is_active = ctx->is_active; ctx->is_active &= ~event_type; if (likely(!ctx->nr_events)) return; update_context_time(ctx); update_cgrp_time_from_cpuctx(cpuctx); if (!ctx->nr_active) return; perf_pmu_disable(ctx->pmu); if ((is_active & EVENT_PINNED) && (event_type & EVENT_PINNED)) { list_for_each_entry(event, &ctx->pinned_groups, group_entry) group_sched_out(event, cpuctx, ctx); } if ((is_active & EVENT_FLEXIBLE) && (event_type & EVENT_FLEXIBLE)) { list_for_each_entry(event, &ctx->flexible_groups, group_entry) group_sched_out(event, cpuctx, ctx); } perf_pmu_enable(ctx->pmu); } /* * Test whether two contexts are equivalent, i.e. whether they * have both been cloned from the same version of the same context * and they both have the same number of enabled events. * If the number of enabled events is the same, then the set * of enabled events should be the same, because these are both * inherited contexts, therefore we can't access individual events * in them directly with an fd; we can only enable/disable all * events via prctl, or enable/disable all events in a family * via ioctl, which will have the same effect on both contexts. */ static int context_equiv(struct perf_event_context *ctx1, struct perf_event_context *ctx2) { return ctx1->parent_ctx && ctx1->parent_ctx == ctx2->parent_ctx && ctx1->parent_gen == ctx2->parent_gen && !ctx1->pin_count && !ctx2->pin_count; } static void __perf_event_sync_stat(struct perf_event *event, struct perf_event *next_event) { u64 value; if (!event->attr.inherit_stat) return; /* * Update the event value, we cannot use perf_event_read() * because we're in the middle of a context switch and have IRQs * disabled, which upsets smp_call_function_single(), however * we know the event must be on the current CPU, therefore we * don't need to use it. */ switch (event->state) { case PERF_EVENT_STATE_ACTIVE: event->pmu->read(event); /* fall-through */ case PERF_EVENT_STATE_INACTIVE: update_event_times(event); break; default: break; } /* * In order to keep per-task stats reliable we need to flip the event * values when we flip the contexts. */ value = local64_read(&next_event->count); value = local64_xchg(&event->count, value); local64_set(&next_event->count, value); swap(event->total_time_enabled, next_event->total_time_enabled); swap(event->total_time_running, next_event->total_time_running); /* * Since we swizzled the values, update the user visible data too. */ perf_event_update_userpage(event); perf_event_update_userpage(next_event); } static void perf_event_sync_stat(struct perf_event_context *ctx, struct perf_event_context *next_ctx) { struct perf_event *event, *next_event; if (!ctx->nr_stat) return; update_context_time(ctx); event = list_first_entry(&ctx->event_list, struct perf_event, event_entry); next_event = list_first_entry(&next_ctx->event_list, struct perf_event, event_entry); while (&event->event_entry != &ctx->event_list && &next_event->event_entry != &next_ctx->event_list) { __perf_event_sync_stat(event, next_event); event = list_next_entry(event, event_entry); next_event = list_next_entry(next_event, event_entry); } } static void perf_event_context_sched_out(struct task_struct *task, int ctxn, struct task_struct *next) { struct perf_event_context *ctx = task->perf_event_ctxp[ctxn]; struct perf_event_context *next_ctx; struct perf_event_context *parent; struct perf_cpu_context *cpuctx; int do_switch = 1; if (likely(!ctx)) return; cpuctx = __get_cpu_context(ctx); if (!cpuctx->task_ctx) return; rcu_read_lock(); parent = rcu_dereference(ctx->parent_ctx); next_ctx = next->perf_event_ctxp[ctxn]; if (parent && next_ctx && rcu_dereference(next_ctx->parent_ctx) == parent) { /* * Looks like the two contexts are clones, so we might be * able to optimize the context switch. We lock both * contexts and check that they are clones under the * lock (including re-checking that neither has been * uncloned in the meantime). It doesn't matter which * order we take the locks because no other cpu could * be trying to lock both of these tasks. */ raw_spin_lock(&ctx->lock); raw_spin_lock_nested(&next_ctx->lock, SINGLE_DEPTH_NESTING); if (context_equiv(ctx, next_ctx)) { /* * XXX do we need a memory barrier of sorts * wrt to rcu_dereference() of perf_event_ctxp */ task->perf_event_ctxp[ctxn] = next_ctx; next->perf_event_ctxp[ctxn] = ctx; ctx->task = next; next_ctx->task = task; do_switch = 0; perf_event_sync_stat(ctx, next_ctx); } raw_spin_unlock(&next_ctx->lock); raw_spin_unlock(&ctx->lock); } rcu_read_unlock(); if (do_switch) { raw_spin_lock(&ctx->lock); ctx_sched_out(ctx, cpuctx, EVENT_ALL); cpuctx->task_ctx = NULL; raw_spin_unlock(&ctx->lock); } } #define for_each_task_context_nr(ctxn) \ for ((ctxn) = 0; (ctxn) < perf_nr_task_contexts; (ctxn)++) /* * Called from scheduler to remove the events of the current task, * with interrupts disabled. * * We stop each event and update the event value in event->count. * * This does not protect us against NMI, but disable() * sets the disabled bit in the control field of event _before_ * accessing the event control register. If a NMI hits, then it will * not restart the event. */ void __perf_event_task_sched_out(struct task_struct *task, struct task_struct *next) { int ctxn; for_each_task_context_nr(ctxn) perf_event_context_sched_out(task, ctxn, next); /* * if cgroup events exist on this CPU, then we need * to check if we have to switch out PMU state. * cgroup event are system-wide mode only */ if (atomic_read(&__get_cpu_var(perf_cgroup_events))) perf_cgroup_sched_out(task, next); } static void task_ctx_sched_out(struct perf_event_context *ctx) { struct perf_cpu_context *cpuctx = __get_cpu_context(ctx); if (!cpuctx->task_ctx) return; if (WARN_ON_ONCE(ctx != cpuctx->task_ctx)) return; ctx_sched_out(ctx, cpuctx, EVENT_ALL); cpuctx->task_ctx = NULL; } /* * Called with IRQs disabled */ static void cpu_ctx_sched_out(struct perf_cpu_context *cpuctx, enum event_type_t event_type) { ctx_sched_out(&cpuctx->ctx, cpuctx, event_type); } static void ctx_pinned_sched_in(struct perf_event_context *ctx, struct perf_cpu_context *cpuctx) { struct perf_event *event; list_for_each_entry(event, &ctx->pinned_groups, group_entry) { if (event->state <= PERF_EVENT_STATE_OFF) continue; if (!event_filter_match(event)) continue; /* may need to reset tstamp_enabled */ if (is_cgroup_event(event)) perf_cgroup_mark_enabled(event, ctx); if (group_can_go_on(event, cpuctx, 1)) group_sched_in(event, cpuctx, ctx); /* * If this pinned group hasn't been scheduled, * put it in error state. */ if (event->state == PERF_EVENT_STATE_INACTIVE) { update_group_times(event); event->state = PERF_EVENT_STATE_ERROR; } } } static void ctx_flexible_sched_in(struct perf_event_context *ctx, struct perf_cpu_context *cpuctx) { struct perf_event *event; int can_add_hw = 1; list_for_each_entry(event, &ctx->flexible_groups, group_entry) { /* Ignore events in OFF or ERROR state */ if (event->state <= PERF_EVENT_STATE_OFF) continue; /* * Listen to the 'cpu' scheduling filter constraint * of events: */ if (!event_filter_match(event)) continue; /* may need to reset tstamp_enabled */ if (is_cgroup_event(event)) perf_cgroup_mark_enabled(event, ctx); if (group_can_go_on(event, cpuctx, can_add_hw)) { if (group_sched_in(event, cpuctx, ctx)) can_add_hw = 0; } } } static void ctx_sched_in(struct perf_event_context *ctx, struct perf_cpu_context *cpuctx, enum event_type_t event_type, struct task_struct *task) { u64 now; int is_active = ctx->is_active; ctx->is_active |= event_type; if (likely(!ctx->nr_events)) return; now = perf_clock(); ctx->timestamp = now; perf_cgroup_set_timestamp(task, ctx); /* * First go through the list and put on any pinned groups * in order to give them the best chance of going on. */ if (!(is_active & EVENT_PINNED) && (event_type & EVENT_PINNED)) ctx_pinned_sched_in(ctx, cpuctx); /* Then walk through the lower prio flexible groups */ if (!(is_active & EVENT_FLEXIBLE) && (event_type & EVENT_FLEXIBLE)) ctx_flexible_sched_in(ctx, cpuctx); } static void cpu_ctx_sched_in(struct perf_cpu_context *cpuctx, enum event_type_t event_type, struct task_struct *task) { struct perf_event_context *ctx = &cpuctx->ctx; ctx_sched_in(ctx, cpuctx, event_type, task); } static void perf_event_context_sched_in(struct perf_event_context *ctx, struct task_struct *task) { struct perf_cpu_context *cpuctx; cpuctx = __get_cpu_context(ctx); if (cpuctx->task_ctx == ctx) return; perf_ctx_lock(cpuctx, ctx); perf_pmu_disable(ctx->pmu); /* * We want to keep the following priority order: * cpu pinned (that don't need to move), task pinned, * cpu flexible, task flexible. */ cpu_ctx_sched_out(cpuctx, EVENT_FLEXIBLE); if (ctx->nr_events) cpuctx->task_ctx = ctx; perf_event_sched_in(cpuctx, cpuctx->task_ctx, task); perf_pmu_enable(ctx->pmu); perf_ctx_unlock(cpuctx, ctx); /* * Since these rotations are per-cpu, we need to ensure the * cpu-context we got scheduled on is actually rotating. */ perf_pmu_rotate_start(ctx->pmu); } /* * When sampling the branck stack in system-wide, it may be necessary * to flush the stack on context switch. This happens when the branch * stack does not tag its entries with the pid of the current task. * Otherwise it becomes impossible to associate a branch entry with a * task. This ambiguity is more likely to appear when the branch stack * supports priv level filtering and the user sets it to monitor only * at the user level (which could be a useful measurement in system-wide * mode). In that case, the risk is high of having a branch stack with * branch from multiple tasks. Flushing may mean dropping the existing * entries or stashing them somewhere in the PMU specific code layer. * * This function provides the context switch callback to the lower code * layer. It is invoked ONLY when there is at least one system-wide context * with at least one active event using taken branch sampling. */ static void perf_branch_stack_sched_in(struct task_struct *prev, struct task_struct *task) { struct perf_cpu_context *cpuctx; struct pmu *pmu; unsigned long flags; /* no need to flush branch stack if not changing task */ if (prev == task) return; local_irq_save(flags); rcu_read_lock(); list_for_each_entry_rcu(pmu, &pmus, entry) { cpuctx = this_cpu_ptr(pmu->pmu_cpu_context); /* * check if the context has at least one * event using PERF_SAMPLE_BRANCH_STACK */ if (cpuctx->ctx.nr_branch_stack > 0 && pmu->flush_branch_stack) { pmu = cpuctx->ctx.pmu; perf_ctx_lock(cpuctx, cpuctx->task_ctx); perf_pmu_disable(pmu); pmu->flush_branch_stack(); perf_pmu_enable(pmu); perf_ctx_unlock(cpuctx, cpuctx->task_ctx); } } rcu_read_unlock(); local_irq_restore(flags); } /* * Called from scheduler to add the events of the current task * with interrupts disabled. * * We restore the event value and then enable it. * * This does not protect us against NMI, but enable() * sets the enabled bit in the control field of event _before_ * accessing the event control register. If a NMI hits, then it will * keep the event running. */ void __perf_event_task_sched_in(struct task_struct *prev, struct task_struct *task) { struct perf_event_context *ctx; int ctxn; for_each_task_context_nr(ctxn) { ctx = task->perf_event_ctxp[ctxn]; if (likely(!ctx)) continue; perf_event_context_sched_in(ctx, task); } /* * if cgroup events exist on this CPU, then we need * to check if we have to switch in PMU state. * cgroup event are system-wide mode only */ if (atomic_read(&__get_cpu_var(perf_cgroup_events))) perf_cgroup_sched_in(prev, task); /* check for system-wide branch_stack events */ if (atomic_read(&__get_cpu_var(perf_branch_stack_events))) perf_branch_stack_sched_in(prev, task); } static u64 perf_calculate_period(struct perf_event *event, u64 nsec, u64 count) { u64 frequency = event->attr.sample_freq; u64 sec = NSEC_PER_SEC; u64 divisor, dividend; int count_fls, nsec_fls, frequency_fls, sec_fls; count_fls = fls64(count); nsec_fls = fls64(nsec); frequency_fls = fls64(frequency); sec_fls = 30; /* * We got @count in @nsec, with a target of sample_freq HZ * the target period becomes: * * @count * 10^9 * period = ------------------- * @nsec * sample_freq * */ /* * Reduce accuracy by one bit such that @a and @b converge * to a similar magnitude. */ #define REDUCE_FLS(a, b) \ do { \ if (a##_fls > b##_fls) { \ a >>= 1; \ a##_fls--; \ } else { \ b >>= 1; \ b##_fls--; \ } \ } while (0) /* * Reduce accuracy until either term fits in a u64, then proceed with * the other, so that finally we can do a u64/u64 division. */ while (count_fls + sec_fls > 64 && nsec_fls + frequency_fls > 64) { REDUCE_FLS(nsec, frequency); REDUCE_FLS(sec, count); } if (count_fls + sec_fls > 64) { divisor = nsec * frequency; while (count_fls + sec_fls > 64) { REDUCE_FLS(count, sec); divisor >>= 1; } dividend = count * sec; } else { dividend = count * sec; while (nsec_fls + frequency_fls > 64) { REDUCE_FLS(nsec, frequency); dividend >>= 1; } divisor = nsec * frequency; } if (!divisor) return dividend; return div64_u64(dividend, divisor); } static DEFINE_PER_CPU(int, perf_throttled_count); static DEFINE_PER_CPU(u64, perf_throttled_seq); static void perf_adjust_period(struct perf_event *event, u64 nsec, u64 count, bool disable) { struct hw_perf_event *hwc = &event->hw; s64 period, sample_period; s64 delta; period = perf_calculate_period(event, nsec, count); delta = (s64)(period - hwc->sample_period); delta = (delta + 7) / 8; /* low pass filter */ sample_period = hwc->sample_period + delta; if (!sample_period) sample_period = 1; hwc->sample_period = sample_period; if (local64_read(&hwc->period_left) > 8*sample_period) { if (disable) event->pmu->stop(event, PERF_EF_UPDATE); local64_set(&hwc->period_left, 0); if (disable) event->pmu->start(event, PERF_EF_RELOAD); } } /* * combine freq adjustment with unthrottling to avoid two passes over the * events. At the same time, make sure, having freq events does not change * the rate of unthrottling as that would introduce bias. */ static void perf_adjust_freq_unthr_context(struct perf_event_context *ctx, int needs_unthr) { struct perf_event *event; struct hw_perf_event *hwc; u64 now, period = TICK_NSEC; s64 delta; /* * only need to iterate over all events iff: * - context have events in frequency mode (needs freq adjust) * - there are events to unthrottle on this cpu */ if (!(ctx->nr_freq || needs_unthr)) return; raw_spin_lock(&ctx->lock); perf_pmu_disable(ctx->pmu); list_for_each_entry_rcu(event, &ctx->event_list, event_entry) { if (event->state != PERF_EVENT_STATE_ACTIVE) continue; if (!event_filter_match(event)) continue; hwc = &event->hw; if (needs_unthr && hwc->interrupts == MAX_INTERRUPTS) { hwc->interrupts = 0; perf_log_throttle(event, 1); event->pmu->start(event, 0); } if (!event->attr.freq || !event->attr.sample_freq) continue; /* * stop the event and update event->count */ event->pmu->stop(event, PERF_EF_UPDATE); now = local64_read(&event->count); delta = now - hwc->freq_count_stamp; hwc->freq_count_stamp = now; /* * restart the event * reload only if value has changed * we have stopped the event so tell that * to perf_adjust_period() to avoid stopping it * twice. */ if (delta > 0) perf_adjust_period(event, period, delta, false); event->pmu->start(event, delta > 0 ? PERF_EF_RELOAD : 0); } perf_pmu_enable(ctx->pmu); raw_spin_unlock(&ctx->lock); } /* * Round-robin a context's events: */ static void rotate_ctx(struct perf_event_context *ctx) { /* * Rotate the first entry last of non-pinned groups. Rotation might be * disabled by the inheritance code. */ if (!ctx->rotate_disable) list_rotate_left(&ctx->flexible_groups); } /* * perf_pmu_rotate_start() and perf_rotate_context() are fully serialized * because they're strictly cpu affine and rotate_start is called with IRQs * disabled, while rotate_context is called from IRQ context. */ static void perf_rotate_context(struct perf_cpu_context *cpuctx) { struct perf_event_context *ctx = NULL; int rotate = 0, remove = 1; if (cpuctx->ctx.nr_events) { remove = 0; if (cpuctx->ctx.nr_events != cpuctx->ctx.nr_active) rotate = 1; } ctx = cpuctx->task_ctx; if (ctx && ctx->nr_events) { remove = 0; if (ctx->nr_events != ctx->nr_active) rotate = 1; } if (!rotate) goto done; perf_ctx_lock(cpuctx, cpuctx->task_ctx); perf_pmu_disable(cpuctx->ctx.pmu); cpu_ctx_sched_out(cpuctx, EVENT_FLEXIBLE); if (ctx) ctx_sched_out(ctx, cpuctx, EVENT_FLEXIBLE); rotate_ctx(&cpuctx->ctx); if (ctx) rotate_ctx(ctx); perf_event_sched_in(cpuctx, ctx, current); perf_pmu_enable(cpuctx->ctx.pmu); perf_ctx_unlock(cpuctx, cpuctx->task_ctx); done: if (remove) list_del_init(&cpuctx->rotation_list); } #ifdef CONFIG_NO_HZ_FULL bool perf_event_can_stop_tick(void) { if (list_empty(&__get_cpu_var(rotation_list))) return true; else return false; } #endif void perf_event_task_tick(void) { struct list_head *head = &__get_cpu_var(rotation_list); struct perf_cpu_context *cpuctx, *tmp; struct perf_event_context *ctx; int throttled; WARN_ON(!irqs_disabled()); __this_cpu_inc(perf_throttled_seq); throttled = __this_cpu_xchg(perf_throttled_count, 0); list_for_each_entry_safe(cpuctx, tmp, head, rotation_list) { ctx = &cpuctx->ctx; perf_adjust_freq_unthr_context(ctx, throttled); ctx = cpuctx->task_ctx; if (ctx) perf_adjust_freq_unthr_context(ctx, throttled); if (cpuctx->jiffies_interval == 1 || !(jiffies % cpuctx->jiffies_interval)) perf_rotate_context(cpuctx); } } static int event_enable_on_exec(struct perf_event *event, struct perf_event_context *ctx) { if (!event->attr.enable_on_exec) return 0; event->attr.enable_on_exec = 0; if (event->state >= PERF_EVENT_STATE_INACTIVE) return 0; __perf_event_mark_enabled(event); return 1; } /* * Enable all of a task's events that have been marked enable-on-exec. * This expects task == current. */ static void perf_event_enable_on_exec(struct perf_event_context *ctx) { struct perf_event *event; unsigned long flags; int enabled = 0; int ret; local_irq_save(flags); if (!ctx || !ctx->nr_events) goto out; /* * We must ctxsw out cgroup events to avoid conflict * when invoking perf_task_event_sched_in() later on * in this function. Otherwise we end up trying to * ctxswin cgroup events which are already scheduled * in. */ perf_cgroup_sched_out(current, NULL); raw_spin_lock(&ctx->lock); task_ctx_sched_out(ctx); list_for_each_entry(event, &ctx->event_list, event_entry) { ret = event_enable_on_exec(event, ctx); if (ret) enabled = 1; } /* * Unclone this context if we enabled any event. */ if (enabled) unclone_ctx(ctx); raw_spin_unlock(&ctx->lock); /* * Also calls ctxswin for cgroup events, if any: */ perf_event_context_sched_in(ctx, ctx->task); out: local_irq_restore(flags); } /* * Cross CPU call to read the hardware event */ static void __perf_event_read(void *info) { struct perf_event *event = info; struct perf_event_context *ctx = event->ctx; struct perf_cpu_context *cpuctx = __get_cpu_context(ctx); /* * If this is a task context, we need to check whether it is * the current task context of this cpu. If not it has been * scheduled out before the smp call arrived. In that case * event->count would have been updated to a recent sample * when the event was scheduled out. */ if (ctx->task && cpuctx->task_ctx != ctx) return; raw_spin_lock(&ctx->lock); if (ctx->is_active) { update_context_time(ctx); update_cgrp_time_from_event(event); } update_event_times(event); if (event->state == PERF_EVENT_STATE_ACTIVE) event->pmu->read(event); raw_spin_unlock(&ctx->lock); } static inline u64 perf_event_count(struct perf_event *event) { return local64_read(&event->count) + atomic64_read(&event->child_count); } static u64 perf_event_read(struct perf_event *event) { /* * If event is enabled and currently active on a CPU, update the * value in the event structure: */ if (event->state == PERF_EVENT_STATE_ACTIVE) { smp_call_function_single(event->oncpu, __perf_event_read, event, 1); } else if (event->state == PERF_EVENT_STATE_INACTIVE) { struct perf_event_context *ctx = event->ctx; unsigned long flags; raw_spin_lock_irqsave(&ctx->lock, flags); /* * may read while context is not active * (e.g., thread is blocked), in that case * we cannot update context time */ if (ctx->is_active) { update_context_time(ctx); update_cgrp_time_from_event(event); } update_event_times(event); raw_spin_unlock_irqrestore(&ctx->lock, flags); } return perf_event_count(event); } /* * Initialize the perf_event context in a task_struct: */ static void __perf_event_init_context(struct perf_event_context *ctx) { raw_spin_lock_init(&ctx->lock); mutex_init(&ctx->mutex); INIT_LIST_HEAD(&ctx->pinned_groups); INIT_LIST_HEAD(&ctx->flexible_groups); INIT_LIST_HEAD(&ctx->event_list); atomic_set(&ctx->refcount, 1); } static struct perf_event_context * alloc_perf_context(struct pmu *pmu, struct task_struct *task) { struct perf_event_context *ctx; ctx = kzalloc(sizeof(struct perf_event_context), GFP_KERNEL); if (!ctx) return NULL; __perf_event_init_context(ctx); if (task) { ctx->task = task; get_task_struct(task); } ctx->pmu = pmu; return ctx; } static struct task_struct * find_lively_task_by_vpid(pid_t vpid) { struct task_struct *task; int err; rcu_read_lock(); if (!vpid) task = current; else task = find_task_by_vpid(vpid); if (task) get_task_struct(task); rcu_read_unlock(); if (!task) return ERR_PTR(-ESRCH); /* Reuse ptrace permission checks for now. */ err = -EACCES; if (!ptrace_may_access(task, PTRACE_MODE_READ)) goto errout; return task; errout: put_task_struct(task); return ERR_PTR(err); } /* * Returns a matching context with refcount and pincount. */ static struct perf_event_context * find_get_context(struct pmu *pmu, struct task_struct *task, int cpu) { struct perf_event_context *ctx; struct perf_cpu_context *cpuctx; unsigned long flags; int ctxn, err; if (!task) { /* Must be root to operate on a CPU event: */ if (perf_paranoid_cpu() && !capable(CAP_SYS_ADMIN)) return ERR_PTR(-EACCES); /* * We could be clever and allow to attach a event to an * offline CPU and activate it when the CPU comes up, but * that's for later. */ if (!cpu_online(cpu)) return ERR_PTR(-ENODEV); cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu); ctx = &cpuctx->ctx; get_ctx(ctx); ++ctx->pin_count; return ctx; } err = -EINVAL; ctxn = pmu->task_ctx_nr; if (ctxn < 0) goto errout; retry: ctx = perf_lock_task_context(task, ctxn, &flags); if (ctx) { unclone_ctx(ctx); ++ctx->pin_count; raw_spin_unlock_irqrestore(&ctx->lock, flags); } else { ctx = alloc_perf_context(pmu, task); err = -ENOMEM; if (!ctx) goto errout; err = 0; mutex_lock(&task->perf_event_mutex); /* * If it has already passed perf_event_exit_task(). * we must see PF_EXITING, it takes this mutex too. */ if (task->flags & PF_EXITING) err = -ESRCH; else if (task->perf_event_ctxp[ctxn]) err = -EAGAIN; else { get_ctx(ctx); ++ctx->pin_count; rcu_assign_pointer(task->perf_event_ctxp[ctxn], ctx); } mutex_unlock(&task->perf_event_mutex); if (unlikely(err)) { put_ctx(ctx); if (err == -EAGAIN) goto retry; goto errout; } } return ctx; errout: return ERR_PTR(err); } static void perf_event_free_filter(struct perf_event *event); static void free_event_rcu(struct rcu_head *head) { struct perf_event *event; event = container_of(head, struct perf_event, rcu_head); if (event->ns) put_pid_ns(event->ns); perf_event_free_filter(event); kfree(event); } static void ring_buffer_put(struct ring_buffer *rb); static void ring_buffer_detach(struct perf_event *event, struct ring_buffer *rb); static void free_event(struct perf_event *event) { irq_work_sync(&event->pending); if (!event->parent) { if (event->attach_state & PERF_ATTACH_TASK) static_key_slow_dec_deferred(&perf_sched_events); if (event->attr.mmap || event->attr.mmap_data) atomic_dec(&nr_mmap_events); if (event->attr.comm) atomic_dec(&nr_comm_events); if (event->attr.task) atomic_dec(&nr_task_events); if (event->attr.sample_type & PERF_SAMPLE_CALLCHAIN) put_callchain_buffers(); if (is_cgroup_event(event)) { atomic_dec(&per_cpu(perf_cgroup_events, event->cpu)); static_key_slow_dec_deferred(&perf_sched_events); } if (has_branch_stack(event)) { static_key_slow_dec_deferred(&perf_sched_events); /* is system-wide event */ if (!(event->attach_state & PERF_ATTACH_TASK)) { atomic_dec(&per_cpu(perf_branch_stack_events, event->cpu)); } } } if (event->rb) { struct ring_buffer *rb; /* * Can happen when we close an event with re-directed output. * * Since we have a 0 refcount, perf_mmap_close() will skip * over us; possibly making our ring_buffer_put() the last. */ mutex_lock(&event->mmap_mutex); rb = event->rb; if (rb) { rcu_assign_pointer(event->rb, NULL); ring_buffer_detach(event, rb); ring_buffer_put(rb); /* could be last */ } mutex_unlock(&event->mmap_mutex); } if (is_cgroup_event(event)) perf_detach_cgroup(event); if (event->destroy) event->destroy(event); if (event->ctx) put_ctx(event->ctx); call_rcu(&event->rcu_head, free_event_rcu); } int perf_event_release_kernel(struct perf_event *event) { struct perf_event_context *ctx = event->ctx; WARN_ON_ONCE(ctx->parent_ctx); /* * There are two ways this annotation is useful: * * 1) there is a lock recursion from perf_event_exit_task * see the comment there. * * 2) there is a lock-inversion with mmap_sem through * perf_event_read_group(), which takes faults while * holding ctx->mutex, however this is called after * the last filedesc died, so there is no possibility * to trigger the AB-BA case. */ mutex_lock_nested(&ctx->mutex, SINGLE_DEPTH_NESTING); perf_remove_from_context(event, true); mutex_unlock(&ctx->mutex); free_event(event); return 0; } EXPORT_SYMBOL_GPL(perf_event_release_kernel); /* * Called when the last reference to the file is gone. */ static void put_event(struct perf_event *event) { struct task_struct *owner; if (!atomic_long_dec_and_test(&event->refcount)) return; rcu_read_lock(); owner = ACCESS_ONCE(event->owner); /* * Matches the smp_wmb() in perf_event_exit_task(). If we observe * !owner it means the list deletion is complete and we can indeed * free this event, otherwise we need to serialize on * owner->perf_event_mutex. */ smp_read_barrier_depends(); if (owner) { /* * Since delayed_put_task_struct() also drops the last * task reference we can safely take a new reference * while holding the rcu_read_lock(). */ get_task_struct(owner); } rcu_read_unlock(); if (owner) { mutex_lock(&owner->perf_event_mutex); /* * We have to re-check the event->owner field, if it is cleared * we raced with perf_event_exit_task(), acquiring the mutex * ensured they're done, and we can proceed with freeing the * event. */ if (event->owner) list_del_init(&event->owner_entry); mutex_unlock(&owner->perf_event_mutex); put_task_struct(owner); } perf_event_release_kernel(event); } static int perf_release(struct inode *inode, struct file *file) { put_event(file->private_data); return 0; } u64 perf_event_read_value(struct perf_event *event, u64 *enabled, u64 *running) { struct perf_event *child; u64 total = 0; *enabled = 0; *running = 0; mutex_lock(&event->child_mutex); total += perf_event_read(event); *enabled += event->total_time_enabled + atomic64_read(&event->child_total_time_enabled); *running += event->total_time_running + atomic64_read(&event->child_total_time_running); list_for_each_entry(child, &event->child_list, child_list) { total += perf_event_read(child); *enabled += child->total_time_enabled; *running += child->total_time_running; } mutex_unlock(&event->child_mutex); return total; } EXPORT_SYMBOL_GPL(perf_event_read_value); static int perf_event_read_group(struct perf_event *event, u64 read_format, char __user *buf) { struct perf_event *leader = event->group_leader, *sub; int n = 0, size = 0, ret = -EFAULT; struct perf_event_context *ctx = leader->ctx; u64 values[5]; u64 count, enabled, running; mutex_lock(&ctx->mutex); count = perf_event_read_value(leader, &enabled, &running); values[n++] = 1 + leader->nr_siblings; if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED) values[n++] = enabled; if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING) values[n++] = running; values[n++] = count; if (read_format & PERF_FORMAT_ID) values[n++] = primary_event_id(leader); size = n * sizeof(u64); if (copy_to_user(buf, values, size)) goto unlock; ret = size; list_for_each_entry(sub, &leader->sibling_list, group_entry) { n = 0; values[n++] = perf_event_read_value(sub, &enabled, &running); if (read_format & PERF_FORMAT_ID) values[n++] = primary_event_id(sub); size = n * sizeof(u64); if (copy_to_user(buf + ret, values, size)) { ret = -EFAULT; goto unlock; } ret += size; } unlock: mutex_unlock(&ctx->mutex); return ret; } static int perf_event_read_one(struct perf_event *event, u64 read_format, char __user *buf) { u64 enabled, running; u64 values[4]; int n = 0; values[n++] = perf_event_read_value(event, &enabled, &running); if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED) values[n++] = enabled; if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING) values[n++] = running; if (read_format & PERF_FORMAT_ID) values[n++] = primary_event_id(event); if (copy_to_user(buf, values, n * sizeof(u64))) return -EFAULT; return n * sizeof(u64); } /* * Read the performance event - simple non blocking version for now */ static ssize_t perf_read_hw(struct perf_event *event, char __user *buf, size_t count) { u64 read_format = event->attr.read_format; int ret; /* * Return end-of-file for a read on a event that is in * error state (i.e. because it was pinned but it couldn't be * scheduled on to the CPU at some point). */ if (event->state == PERF_EVENT_STATE_ERROR) return 0; if (count < event->read_size) return -ENOSPC; WARN_ON_ONCE(event->ctx->parent_ctx); if (read_format & PERF_FORMAT_GROUP) ret = perf_event_read_group(event, read_format, buf); else ret = perf_event_read_one(event, read_format, buf); return ret; } static ssize_t perf_read(struct file *file, char __user *buf, size_t count, loff_t *ppos) { struct perf_event *event = file->private_data; return perf_read_hw(event, buf, count); } static unsigned int perf_poll(struct file *file, poll_table *wait) { struct perf_event *event = file->private_data; struct ring_buffer *rb; unsigned int events = POLL_HUP; /* * Pin the event->rb by taking event->mmap_mutex; otherwise * perf_event_set_output() can swizzle our rb and make us miss wakeups. */ mutex_lock(&event->mmap_mutex); rb = event->rb; if (rb) events = atomic_xchg(&rb->poll, 0); mutex_unlock(&event->mmap_mutex); poll_wait(file, &event->waitq, wait); return events; } static void perf_event_reset(struct perf_event *event) { (void)perf_event_read(event); local64_set(&event->count, 0); perf_event_update_userpage(event); } /* * Holding the top-level event's child_mutex means that any * descendant process that has inherited this event will block * in sync_child_event if it goes to exit, thus satisfying the * task existence requirements of perf_event_enable/disable. */ static void perf_event_for_each_child(struct perf_event *event, void (*func)(struct perf_event *)) { struct perf_event *child; WARN_ON_ONCE(event->ctx->parent_ctx); mutex_lock(&event->child_mutex); func(event); list_for_each_entry(child, &event->child_list, child_list) func(child); mutex_unlock(&event->child_mutex); } static void perf_event_for_each(struct perf_event *event, void (*func)(struct perf_event *)) { struct perf_event_context *ctx = event->ctx; struct perf_event *sibling; WARN_ON_ONCE(ctx->parent_ctx); mutex_lock(&ctx->mutex); event = event->group_leader; perf_event_for_each_child(event, func); list_for_each_entry(sibling, &event->sibling_list, group_entry) perf_event_for_each_child(sibling, func); mutex_unlock(&ctx->mutex); } static int perf_event_period(struct perf_event *event, u64 __user *arg) { struct perf_event_context *ctx = event->ctx; int ret = 0; u64 value; if (!is_sampling_event(event)) return -EINVAL; if (copy_from_user(&value, arg, sizeof(value))) return -EFAULT; if (!value) return -EINVAL; raw_spin_lock_irq(&ctx->lock); if (event->attr.freq) { if (value > sysctl_perf_event_sample_rate) { ret = -EINVAL; goto unlock; } event->attr.sample_freq = value; } else { event->attr.sample_period = value; event->hw.sample_period = value; } unlock: raw_spin_unlock_irq(&ctx->lock); return ret; } static const struct file_operations perf_fops; static inline int perf_fget_light(int fd, struct fd *p) { struct fd f = fdget(fd); if (!f.file) return -EBADF; if (f.file->f_op != &perf_fops) { fdput(f); return -EBADF; } *p = f; return 0; } static int perf_event_set_output(struct perf_event *event, struct perf_event *output_event); static int perf_event_set_filter(struct perf_event *event, void __user *arg); static long perf_ioctl(struct file *file, unsigned int cmd, unsigned long arg) { struct perf_event *event = file->private_data; void (*func)(struct perf_event *); u32 flags = arg; switch (cmd) { case PERF_EVENT_IOC_ENABLE: func = perf_event_enable; break; case PERF_EVENT_IOC_DISABLE: func = perf_event_disable; break; case PERF_EVENT_IOC_RESET: func = perf_event_reset; break; case PERF_EVENT_IOC_REFRESH: return perf_event_refresh(event, arg); case PERF_EVENT_IOC_PERIOD: return perf_event_period(event, (u64 __user *)arg); case PERF_EVENT_IOC_SET_OUTPUT: { int ret; if (arg != -1) { struct perf_event *output_event; struct fd output; ret = perf_fget_light(arg, &output); if (ret) return ret; output_event = output.file->private_data; ret = perf_event_set_output(event, output_event); fdput(output); } else { ret = perf_event_set_output(event, NULL); } return ret; } case PERF_EVENT_IOC_SET_FILTER: return perf_event_set_filter(event, (void __user *)arg); default: return -ENOTTY; } if (flags & PERF_IOC_FLAG_GROUP) perf_event_for_each(event, func); else perf_event_for_each_child(event, func); return 0; } #ifdef CONFIG_COMPAT static long perf_compat_ioctl(struct file *file, unsigned int cmd, unsigned long arg) { switch (_IOC_NR(cmd)) { case _IOC_NR(PERF_EVENT_IOC_SET_FILTER): /* Fix up pointer size (usually 4 -> 8 in 32-on-64-bit case */ if (_IOC_SIZE(cmd) == sizeof(compat_uptr_t)) { cmd &= ~IOCSIZE_MASK; cmd |= sizeof(void *) << IOCSIZE_SHIFT; } break; } return perf_ioctl(file, cmd, arg); } #else # define perf_compat_ioctl NULL #endif int perf_event_task_enable(void) { struct perf_event *event; mutex_lock(¤t->perf_event_mutex); list_for_each_entry(event, ¤t->perf_event_list, owner_entry) perf_event_for_each_child(event, perf_event_enable); mutex_unlock(¤t->perf_event_mutex); return 0; } int perf_event_task_disable(void) { struct perf_event *event; mutex_lock(¤t->perf_event_mutex); list_for_each_entry(event, ¤t->perf_event_list, owner_entry) perf_event_for_each_child(event, perf_event_disable); mutex_unlock(¤t->perf_event_mutex); return 0; } static int perf_event_index(struct perf_event *event) { if (event->hw.state & PERF_HES_STOPPED) return 0; if (event->state != PERF_EVENT_STATE_ACTIVE) return 0; return event->pmu->event_idx(event); } static void calc_timer_values(struct perf_event *event, u64 *now, u64 *enabled, u64 *running) { u64 ctx_time; *now = perf_clock(); ctx_time = event->shadow_ctx_time + *now; *enabled = ctx_time - event->tstamp_enabled; *running = ctx_time - event->tstamp_running; } void __weak arch_perf_update_userpage(struct perf_event_mmap_page *userpg, u64 now) { } /* * Callers need to ensure there can be no nesting of this function, otherwise * the seqlock logic goes bad. We can not serialize this because the arch * code calls this from NMI context. */ void perf_event_update_userpage(struct perf_event *event) { struct perf_event_mmap_page *userpg; struct ring_buffer *rb; u64 enabled, running, now; rcu_read_lock(); /* * compute total_time_enabled, total_time_running * based on snapshot values taken when the event * was last scheduled in. * * we cannot simply called update_context_time() * because of locking issue as we can be called in * NMI context */ calc_timer_values(event, &now, &enabled, &running); rb = rcu_dereference(event->rb); if (!rb) goto unlock; userpg = rb->user_page; /* * Disable preemption so as to not let the corresponding user-space * spin too long if we get preempted. */ preempt_disable(); ++userpg->lock; barrier(); userpg->index = perf_event_index(event); userpg->offset = perf_event_count(event); if (userpg->index) userpg->offset -= local64_read(&event->hw.prev_count); userpg->time_enabled = enabled + atomic64_read(&event->child_total_time_enabled); userpg->time_running = running + atomic64_read(&event->child_total_time_running); arch_perf_update_userpage(userpg, now); barrier(); ++userpg->lock; preempt_enable(); unlock: rcu_read_unlock(); } static int perf_mmap_fault(struct vm_area_struct *vma, struct vm_fault *vmf) { struct perf_event *event = vma->vm_file->private_data; struct ring_buffer *rb; int ret = VM_FAULT_SIGBUS; if (vmf->flags & FAULT_FLAG_MKWRITE) { if (vmf->pgoff == 0) ret = 0; return ret; } rcu_read_lock(); rb = rcu_dereference(event->rb); if (!rb) goto unlock; if (vmf->pgoff && (vmf->flags & FAULT_FLAG_WRITE)) goto unlock; vmf->page = perf_mmap_to_page(rb, vmf->pgoff); if (!vmf->page) goto unlock; get_page(vmf->page); vmf->page->mapping = vma->vm_file->f_mapping; vmf->page->index = vmf->pgoff; ret = 0; unlock: rcu_read_unlock(); return ret; } static void ring_buffer_attach(struct perf_event *event, struct ring_buffer *rb) { unsigned long flags; if (!list_empty(&event->rb_entry)) return; spin_lock_irqsave(&rb->event_lock, flags); if (list_empty(&event->rb_entry)) list_add(&event->rb_entry, &rb->event_list); spin_unlock_irqrestore(&rb->event_lock, flags); } static void ring_buffer_detach(struct perf_event *event, struct ring_buffer *rb) { unsigned long flags; if (list_empty(&event->rb_entry)) return; spin_lock_irqsave(&rb->event_lock, flags); list_del_init(&event->rb_entry); wake_up_all(&event->waitq); spin_unlock_irqrestore(&rb->event_lock, flags); } static void ring_buffer_wakeup(struct perf_event *event) { struct ring_buffer *rb; rcu_read_lock(); rb = rcu_dereference(event->rb); if (rb) { list_for_each_entry_rcu(event, &rb->event_list, rb_entry) wake_up_all(&event->waitq); } rcu_read_unlock(); } static void rb_free_rcu(struct rcu_head *rcu_head) { struct ring_buffer *rb; rb = container_of(rcu_head, struct ring_buffer, rcu_head); rb_free(rb); } static struct ring_buffer *ring_buffer_get(struct perf_event *event) { struct ring_buffer *rb; rcu_read_lock(); rb = rcu_dereference(event->rb); if (rb) { if (!atomic_inc_not_zero(&rb->refcount)) rb = NULL; } rcu_read_unlock(); return rb; } static void ring_buffer_put(struct ring_buffer *rb) { if (!atomic_dec_and_test(&rb->refcount)) return; WARN_ON_ONCE(!list_empty(&rb->event_list)); call_rcu(&rb->rcu_head, rb_free_rcu); } static void perf_mmap_open(struct vm_area_struct *vma) { struct perf_event *event = vma->vm_file->private_data; atomic_inc(&event->mmap_count); atomic_inc(&event->rb->mmap_count); } /* * A buffer can be mmap()ed multiple times; either directly through the same * event, or through other events by use of perf_event_set_output(). * * In order to undo the VM accounting done by perf_mmap() we need to destroy * the buffer here, where we still have a VM context. This means we need * to detach all events redirecting to us. */ static void perf_mmap_close(struct vm_area_struct *vma) { struct perf_event *event = vma->vm_file->private_data; struct ring_buffer *rb = event->rb; struct user_struct *mmap_user = rb->mmap_user; int mmap_locked = rb->mmap_locked; unsigned long size = perf_data_size(rb); atomic_dec(&rb->mmap_count); if (!atomic_dec_and_mutex_lock(&event->mmap_count, &event->mmap_mutex)) return; /* Detach current event from the buffer. */ rcu_assign_pointer(event->rb, NULL); ring_buffer_detach(event, rb); mutex_unlock(&event->mmap_mutex); /* If there's still other mmap()s of this buffer, we're done. */ if (atomic_read(&rb->mmap_count)) { ring_buffer_put(rb); /* can't be last */ return; } /* * No other mmap()s, detach from all other events that might redirect * into the now unreachable buffer. Somewhat complicated by the * fact that rb::event_lock otherwise nests inside mmap_mutex. */ again: rcu_read_lock(); list_for_each_entry_rcu(event, &rb->event_list, rb_entry) { if (!atomic_long_inc_not_zero(&event->refcount)) { /* * This event is en-route to free_event() which will * detach it and remove it from the list. */ continue; } rcu_read_unlock(); mutex_lock(&event->mmap_mutex); /* * Check we didn't race with perf_event_set_output() which can * swizzle the rb from under us while we were waiting to * acquire mmap_mutex. * * If we find a different rb; ignore this event, a next * iteration will no longer find it on the list. We have to * still restart the iteration to make sure we're not now * iterating the wrong list. */ if (event->rb == rb) { rcu_assign_pointer(event->rb, NULL); ring_buffer_detach(event, rb); ring_buffer_put(rb); /* can't be last, we still have one */ } mutex_unlock(&event->mmap_mutex); put_event(event); /* * Restart the iteration; either we're on the wrong list or * destroyed its integrity by doing a deletion. */ goto again; } rcu_read_unlock(); /* * It could be there's still a few 0-ref events on the list; they'll * get cleaned up by free_event() -- they'll also still have their * ref on the rb and will free it whenever they are done with it. * * Aside from that, this buffer is 'fully' detached and unmapped, * undo the VM accounting. */ atomic_long_sub((size >> PAGE_SHIFT) + 1, &mmap_user->locked_vm); vma->vm_mm->pinned_vm -= mmap_locked; free_uid(mmap_user); ring_buffer_put(rb); /* could be last */ } static const struct vm_operations_struct perf_mmap_vmops = { .open = perf_mmap_open, .close = perf_mmap_close, .fault = perf_mmap_fault, .page_mkwrite = perf_mmap_fault, }; static int perf_mmap(struct file *file, struct vm_area_struct *vma) { struct perf_event *event = file->private_data; unsigned long user_locked, user_lock_limit; struct user_struct *user = current_user(); unsigned long locked, lock_limit; struct ring_buffer *rb; unsigned long vma_size; unsigned long nr_pages; long user_extra, extra; int ret = 0, flags = 0; /* * Don't allow mmap() of inherited per-task counters. This would * create a performance issue due to all children writing to the * same rb. */ if (event->cpu == -1 && event->attr.inherit) return -EINVAL; if (!(vma->vm_flags & VM_SHARED)) return -EINVAL; vma_size = vma->vm_end - vma->vm_start; nr_pages = (vma_size / PAGE_SIZE) - 1; /* * If we have rb pages ensure they're a power-of-two number, so we * can do bitmasks instead of modulo. */ if (nr_pages != 0 && !is_power_of_2(nr_pages)) return -EINVAL; if (vma_size != PAGE_SIZE * (1 + nr_pages)) return -EINVAL; if (vma->vm_pgoff != 0) return -EINVAL; WARN_ON_ONCE(event->ctx->parent_ctx); again: mutex_lock(&event->mmap_mutex); if (event->rb) { if (event->rb->nr_pages != nr_pages) { ret = -EINVAL; goto unlock; } if (!atomic_inc_not_zero(&event->rb->mmap_count)) { /* * Raced against perf_mmap_close() through * perf_event_set_output(). Try again, hope for better * luck. */ mutex_unlock(&event->mmap_mutex); goto again; } goto unlock; } user_extra = nr_pages + 1; user_lock_limit = sysctl_perf_event_mlock >> (PAGE_SHIFT - 10); /* * Increase the limit linearly with more CPUs: */ user_lock_limit *= num_online_cpus(); user_locked = atomic_long_read(&user->locked_vm) + user_extra; extra = 0; if (user_locked > user_lock_limit) extra = user_locked - user_lock_limit; lock_limit = rlimit(RLIMIT_MEMLOCK); lock_limit >>= PAGE_SHIFT; locked = vma->vm_mm->pinned_vm + extra; if ((locked > lock_limit) && perf_paranoid_tracepoint_raw() && !capable(CAP_IPC_LOCK)) { ret = -EPERM; goto unlock; } WARN_ON(event->rb); if (vma->vm_flags & VM_WRITE) flags |= RING_BUFFER_WRITABLE; rb = rb_alloc(nr_pages, event->attr.watermark ? event->attr.wakeup_watermark : 0, event->cpu, flags); if (!rb) { ret = -ENOMEM; goto unlock; } atomic_set(&rb->mmap_count, 1); rb->mmap_locked = extra; rb->mmap_user = get_current_user(); atomic_long_add(user_extra, &user->locked_vm); vma->vm_mm->pinned_vm += extra; ring_buffer_attach(event, rb); rcu_assign_pointer(event->rb, rb); perf_event_update_userpage(event); unlock: if (!ret) atomic_inc(&event->mmap_count); mutex_unlock(&event->mmap_mutex); /* * Since pinned accounting is per vm we cannot allow fork() to copy our * vma. */ vma->vm_flags |= VM_DONTCOPY | VM_DONTEXPAND | VM_DONTDUMP; vma->vm_ops = &perf_mmap_vmops; return ret; } static int perf_fasync(int fd, struct file *filp, int on) { struct inode *inode = file_inode(filp); struct perf_event *event = filp->private_data; int retval; mutex_lock(&inode->i_mutex); retval = fasync_helper(fd, filp, on, &event->fasync); mutex_unlock(&inode->i_mutex); if (retval < 0) return retval; return 0; } static const struct file_operations perf_fops = { .llseek = no_llseek, .release = perf_release, .read = perf_read, .poll = perf_poll, .unlocked_ioctl = perf_ioctl, .compat_ioctl = perf_compat_ioctl, .mmap = perf_mmap, .fasync = perf_fasync, }; /* * Perf event wakeup * * If there's data, ensure we set the poll() state and publish everything * to user-space before waking everybody up. */ void perf_event_wakeup(struct perf_event *event) { ring_buffer_wakeup(event); if (event->pending_kill) { kill_fasync(&event->fasync, SIGIO, event->pending_kill); event->pending_kill = 0; } } static void perf_pending_event(struct irq_work *entry) { struct perf_event *event = container_of(entry, struct perf_event, pending); int rctx; rctx = perf_swevent_get_recursion_context(); /* * If we 'fail' here, that's OK, it means recursion is already disabled * and we won't recurse 'further'. */ if (event->pending_disable) { event->pending_disable = 0; __perf_event_disable(event); } if (event->pending_wakeup) { event->pending_wakeup = 0; perf_event_wakeup(event); } if (rctx >= 0) perf_swevent_put_recursion_context(rctx); } /* * We assume there is only KVM supporting the callbacks. * Later on, we might change it to a list if there is * another virtualization implementation supporting the callbacks. */ struct perf_guest_info_callbacks *perf_guest_cbs; int perf_register_guest_info_callbacks(struct perf_guest_info_callbacks *cbs) { perf_guest_cbs = cbs; return 0; } EXPORT_SYMBOL_GPL(perf_register_guest_info_callbacks); int perf_unregister_guest_info_callbacks(struct perf_guest_info_callbacks *cbs) { perf_guest_cbs = NULL; return 0; } EXPORT_SYMBOL_GPL(perf_unregister_guest_info_callbacks); static void perf_output_sample_regs(struct perf_output_handle *handle, struct pt_regs *regs, u64 mask) { int bit; for_each_set_bit(bit, (const unsigned long *) &mask, sizeof(mask) * BITS_PER_BYTE) { u64 val; val = perf_reg_value(regs, bit); perf_output_put(handle, val); } } static void perf_sample_regs_user(struct perf_regs_user *regs_user, struct pt_regs *regs) { if (!user_mode(regs)) { if (current->mm) regs = task_pt_regs(current); else regs = NULL; } if (regs) { regs_user->regs = regs; regs_user->abi = perf_reg_abi(current); } } /* * Get remaining task size from user stack pointer. * * It'd be better to take stack vma map and limit this more * precisly, but there's no way to get it safely under interrupt, * so using TASK_SIZE as limit. */ static u64 perf_ustack_task_size(struct pt_regs *regs) { unsigned long addr = perf_user_stack_pointer(regs); if (!addr || addr >= TASK_SIZE) return 0; return TASK_SIZE - addr; } static u16 perf_sample_ustack_size(u16 stack_size, u16 header_size, struct pt_regs *regs) { u64 task_size; /* No regs, no stack pointer, no dump. */ if (!regs) return 0; /* * Check if we fit in with the requested stack size into the: * - TASK_SIZE * If we don't, we limit the size to the TASK_SIZE. * * - remaining sample size * If we don't, we customize the stack size to * fit in to the remaining sample size. */ task_size = min((u64) USHRT_MAX, perf_ustack_task_size(regs)); stack_size = min(stack_size, (u16) task_size); /* Current header size plus static size and dynamic size. */ header_size += 2 * sizeof(u64); /* Do we fit in with the current stack dump size? */ if ((u16) (header_size + stack_size) < header_size) { /* * If we overflow the maximum size for the sample, * we customize the stack dump size to fit in. */ stack_size = USHRT_MAX - header_size - sizeof(u64); stack_size = round_up(stack_size, sizeof(u64)); } return stack_size; } static void perf_output_sample_ustack(struct perf_output_handle *handle, u64 dump_size, struct pt_regs *regs) { /* Case of a kernel thread, nothing to dump */ if (!regs) { u64 size = 0; perf_output_put(handle, size); } else { unsigned long sp; unsigned int rem; u64 dyn_size; /* * We dump: * static size * - the size requested by user or the best one we can fit * in to the sample max size * data * - user stack dump data * dynamic size * - the actual dumped size */ /* Static size. */ perf_output_put(handle, dump_size); /* Data. */ sp = perf_user_stack_pointer(regs); rem = __output_copy_user(handle, (void *) sp, dump_size); dyn_size = dump_size - rem; perf_output_skip(handle, rem); /* Dynamic size. */ perf_output_put(handle, dyn_size); } } static void __perf_event_header__init_id(struct perf_event_header *header, struct perf_sample_data *data, struct perf_event *event) { u64 sample_type = event->attr.sample_type; data->type = sample_type; header->size += event->id_header_size; if (sample_type & PERF_SAMPLE_TID) { /* namespace issues */ data->tid_entry.pid = perf_event_pid(event, current); data->tid_entry.tid = perf_event_tid(event, current); } if (sample_type & PERF_SAMPLE_TIME) data->time = perf_clock(); if (sample_type & PERF_SAMPLE_ID) data->id = primary_event_id(event); if (sample_type & PERF_SAMPLE_STREAM_ID) data->stream_id = event->id; if (sample_type & PERF_SAMPLE_CPU) { data->cpu_entry.cpu = raw_smp_processor_id(); data->cpu_entry.reserved = 0; } } void perf_event_header__init_id(struct perf_event_header *header, struct perf_sample_data *data, struct perf_event *event) { if (event->attr.sample_id_all) __perf_event_header__init_id(header, data, event); } static void __perf_event__output_id_sample(struct perf_output_handle *handle, struct perf_sample_data *data) { u64 sample_type = data->type; if (sample_type & PERF_SAMPLE_TID) perf_output_put(handle, data->tid_entry); if (sample_type & PERF_SAMPLE_TIME) perf_output_put(handle, data->time); if (sample_type & PERF_SAMPLE_ID) perf_output_put(handle, data->id); if (sample_type & PERF_SAMPLE_STREAM_ID) perf_output_put(handle, data->stream_id); if (sample_type & PERF_SAMPLE_CPU) perf_output_put(handle, data->cpu_entry); } void perf_event__output_id_sample(struct perf_event *event, struct perf_output_handle *handle, struct perf_sample_data *sample) { if (event->attr.sample_id_all) __perf_event__output_id_sample(handle, sample); } static void perf_output_read_one(struct perf_output_handle *handle, struct perf_event *event, u64 enabled, u64 running) { u64 read_format = event->attr.read_format; u64 values[4]; int n = 0; values[n++] = perf_event_count(event); if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED) { values[n++] = enabled + atomic64_read(&event->child_total_time_enabled); } if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING) { values[n++] = running + atomic64_read(&event->child_total_time_running); } if (read_format & PERF_FORMAT_ID) values[n++] = primary_event_id(event); __output_copy(handle, values, n * sizeof(u64)); } /* * XXX PERF_FORMAT_GROUP vs inherited events seems difficult. */ static void perf_output_read_group(struct perf_output_handle *handle, struct perf_event *event, u64 enabled, u64 running) { struct perf_event *leader = event->group_leader, *sub; u64 read_format = event->attr.read_format; u64 values[5]; int n = 0; values[n++] = 1 + leader->nr_siblings; if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED) values[n++] = enabled; if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING) values[n++] = running; if (leader != event) leader->pmu->read(leader); values[n++] = perf_event_count(leader); if (read_format & PERF_FORMAT_ID) values[n++] = primary_event_id(leader); __output_copy(handle, values, n * sizeof(u64)); list_for_each_entry(sub, &leader->sibling_list, group_entry) { n = 0; if (sub != event) sub->pmu->read(sub); values[n++] = perf_event_count(sub); if (read_format & PERF_FORMAT_ID) values[n++] = primary_event_id(sub); __output_copy(handle, values, n * sizeof(u64)); } } #define PERF_FORMAT_TOTAL_TIMES (PERF_FORMAT_TOTAL_TIME_ENABLED|\ PERF_FORMAT_TOTAL_TIME_RUNNING) static void perf_output_read(struct perf_output_handle *handle, struct perf_event *event) { u64 enabled = 0, running = 0, now; u64 read_format = event->attr.read_format; /* * compute total_time_enabled, total_time_running * based on snapshot values taken when the event * was last scheduled in. * * we cannot simply called update_context_time() * because of locking issue as we are called in * NMI context */ if (read_format & PERF_FORMAT_TOTAL_TIMES) calc_timer_values(event, &now, &enabled, &running); if (event->attr.read_format & PERF_FORMAT_GROUP) perf_output_read_group(handle, event, enabled, running); else perf_output_read_one(handle, event, enabled, running); } void perf_output_sample(struct perf_output_handle *handle, struct perf_event_header *header, struct perf_sample_data *data, struct perf_event *event) { u64 sample_type = data->type; perf_output_put(handle, *header); if (sample_type & PERF_SAMPLE_IP) perf_output_put(handle, data->ip); if (sample_type & PERF_SAMPLE_TID) perf_output_put(handle, data->tid_entry); if (sample_type & PERF_SAMPLE_TIME) perf_output_put(handle, data->time); if (sample_type & PERF_SAMPLE_ADDR) perf_output_put(handle, data->addr); if (sample_type & PERF_SAMPLE_ID) perf_output_put(handle, data->id); if (sample_type & PERF_SAMPLE_STREAM_ID) perf_output_put(handle, data->stream_id); if (sample_type & PERF_SAMPLE_CPU) perf_output_put(handle, data->cpu_entry); if (sample_type & PERF_SAMPLE_PERIOD) perf_output_put(handle, data->period); if (sample_type & PERF_SAMPLE_READ) perf_output_read(handle, event); if (sample_type & PERF_SAMPLE_CALLCHAIN) { if (data->callchain) { int size = 1; if (data->callchain) size += data->callchain->nr; size *= sizeof(u64); __output_copy(handle, data->callchain, size); } else { u64 nr = 0; perf_output_put(handle, nr); } } if (sample_type & PERF_SAMPLE_RAW) { if (data->raw) { perf_output_put(handle, data->raw->size); __output_copy(handle, data->raw->data, data->raw->size); } else { struct { u32 size; u32 data; } raw = { .size = sizeof(u32), .data = 0, }; perf_output_put(handle, raw); } } if (!event->attr.watermark) { int wakeup_events = event->attr.wakeup_events; if (wakeup_events) { struct ring_buffer *rb = handle->rb; int events = local_inc_return(&rb->events); if (events >= wakeup_events) { local_sub(wakeup_events, &rb->events); local_inc(&rb->wakeup); } } } if (sample_type & PERF_SAMPLE_BRANCH_STACK) { if (data->br_stack) { size_t size; size = data->br_stack->nr * sizeof(struct perf_branch_entry); perf_output_put(handle, data->br_stack->nr); perf_output_copy(handle, data->br_stack->entries, size); } else { /* * we always store at least the value of nr */ u64 nr = 0; perf_output_put(handle, nr); } } if (sample_type & PERF_SAMPLE_REGS_USER) { u64 abi = data->regs_user.abi; /* * If there are no regs to dump, notice it through * first u64 being zero (PERF_SAMPLE_REGS_ABI_NONE). */ perf_output_put(handle, abi); if (abi) { u64 mask = event->attr.sample_regs_user; perf_output_sample_regs(handle, data->regs_user.regs, mask); } } if (sample_type & PERF_SAMPLE_STACK_USER) perf_output_sample_ustack(handle, data->stack_user_size, data->regs_user.regs); if (sample_type & PERF_SAMPLE_WEIGHT) perf_output_put(handle, data->weight); if (sample_type & PERF_SAMPLE_DATA_SRC) perf_output_put(handle, data->data_src.val); } void perf_prepare_sample(struct perf_event_header *header, struct perf_sample_data *data, struct perf_event *event, struct pt_regs *regs) { u64 sample_type = event->attr.sample_type; header->type = PERF_RECORD_SAMPLE; header->size = sizeof(*header) + event->header_size; header->misc = 0; header->misc |= perf_misc_flags(regs); __perf_event_header__init_id(header, data, event); if (sample_type & PERF_SAMPLE_IP) data->ip = perf_instruction_pointer(regs); if (sample_type & PERF_SAMPLE_CALLCHAIN) { int size = 1; data->callchain = perf_callchain(event, regs); if (data->callchain) size += data->callchain->nr; header->size += size * sizeof(u64); } if (sample_type & PERF_SAMPLE_RAW) { int size = sizeof(u32); if (data->raw) size += data->raw->size; else size += sizeof(u32); WARN_ON_ONCE(size & (sizeof(u64)-1)); header->size += size; } if (sample_type & PERF_SAMPLE_BRANCH_STACK) { int size = sizeof(u64); /* nr */ if (data->br_stack) { size += data->br_stack->nr * sizeof(struct perf_branch_entry); } header->size += size; } if (sample_type & PERF_SAMPLE_REGS_USER) { /* regs dump ABI info */ int size = sizeof(u64); perf_sample_regs_user(&data->regs_user, regs); if (data->regs_user.regs) { u64 mask = event->attr.sample_regs_user; size += hweight64(mask) * sizeof(u64); } header->size += size; } if (sample_type & PERF_SAMPLE_STACK_USER) { /* * Either we need PERF_SAMPLE_STACK_USER bit to be allways * processed as the last one or have additional check added * in case new sample type is added, because we could eat * up the rest of the sample size. */ struct perf_regs_user *uregs = &data->regs_user; u16 stack_size = event->attr.sample_stack_user; u16 size = sizeof(u64); if (!uregs->abi) perf_sample_regs_user(uregs, regs); stack_size = perf_sample_ustack_size(stack_size, header->size, uregs->regs); /* * If there is something to dump, add space for the dump * itself and for the field that tells the dynamic size, * which is how many have been actually dumped. */ if (stack_size) size += sizeof(u64) + stack_size; data->stack_user_size = stack_size; header->size += size; } } static void perf_event_output(struct perf_event *event, struct perf_sample_data *data, struct pt_regs *regs) { struct perf_output_handle handle; struct perf_event_header header; /* protect the callchain buffers */ rcu_read_lock(); perf_prepare_sample(&header, data, event, regs); if (perf_output_begin(&handle, event, header.size)) goto exit; perf_output_sample(&handle, &header, data, event); perf_output_end(&handle); exit: rcu_read_unlock(); } /* * read event_id */ struct perf_read_event { struct perf_event_header header; u32 pid; u32 tid; }; static void perf_event_read_event(struct perf_event *event, struct task_struct *task) { struct perf_output_handle handle; struct perf_sample_data sample; struct perf_read_event read_event = { .header = { .type = PERF_RECORD_READ, .misc = 0, .size = sizeof(read_event) + event->read_size, }, .pid = perf_event_pid(event, task), .tid = perf_event_tid(event, task), }; int ret; perf_event_header__init_id(&read_event.header, &sample, event); ret = perf_output_begin(&handle, event, read_event.header.size); if (ret) return; perf_output_put(&handle, read_event); perf_output_read(&handle, event); perf_event__output_id_sample(event, &handle, &sample); perf_output_end(&handle); } typedef int (perf_event_aux_match_cb)(struct perf_event *event, void *data); typedef void (perf_event_aux_output_cb)(struct perf_event *event, void *data); static void perf_event_aux_ctx(struct perf_event_context *ctx, perf_event_aux_match_cb match, perf_event_aux_output_cb output, void *data) { struct perf_event *event; list_for_each_entry_rcu(event, &ctx->event_list, event_entry) { if (event->state < PERF_EVENT_STATE_INACTIVE) continue; if (!event_filter_match(event)) continue; if (match(event, data)) output(event, data); } } static void perf_event_aux(perf_event_aux_match_cb match, perf_event_aux_output_cb output, void *data, struct perf_event_context *task_ctx) { struct perf_cpu_context *cpuctx; struct perf_event_context *ctx; struct pmu *pmu; int ctxn; rcu_read_lock(); list_for_each_entry_rcu(pmu, &pmus, entry) { cpuctx = get_cpu_ptr(pmu->pmu_cpu_context); if (cpuctx->unique_pmu != pmu) goto next; perf_event_aux_ctx(&cpuctx->ctx, match, output, data); if (task_ctx) goto next; ctxn = pmu->task_ctx_nr; if (ctxn < 0) goto next; ctx = rcu_dereference(current->perf_event_ctxp[ctxn]); if (ctx) perf_event_aux_ctx(ctx, match, output, data); next: put_cpu_ptr(pmu->pmu_cpu_context); } if (task_ctx) { preempt_disable(); perf_event_aux_ctx(task_ctx, match, output, data); preempt_enable(); } rcu_read_unlock(); } /* * task tracking -- fork/exit * * enabled by: attr.comm | attr.mmap | attr.mmap_data | attr.task */ struct perf_task_event { struct task_struct *task; struct perf_event_context *task_ctx; struct { struct perf_event_header header; u32 pid; u32 ppid; u32 tid; u32 ptid; u64 time; } event_id; }; static void perf_event_task_output(struct perf_event *event, void *data) { struct perf_task_event *task_event = data; struct perf_output_handle handle; struct perf_sample_data sample; struct task_struct *task = task_event->task; int ret, size = task_event->event_id.header.size; perf_event_header__init_id(&task_event->event_id.header, &sample, event); ret = perf_output_begin(&handle, event, task_event->event_id.header.size); if (ret) goto out; task_event->event_id.pid = perf_event_pid(event, task); task_event->event_id.ppid = perf_event_pid(event, current); task_event->event_id.tid = perf_event_tid(event, task); task_event->event_id.ptid = perf_event_tid(event, current); perf_output_put(&handle, task_event->event_id); perf_event__output_id_sample(event, &handle, &sample); perf_output_end(&handle); out: task_event->event_id.header.size = size; } static int perf_event_task_match(struct perf_event *event, void *data __maybe_unused) { return event->attr.comm || event->attr.mmap || event->attr.mmap_data || event->attr.task; } static void perf_event_task(struct task_struct *task, struct perf_event_context *task_ctx, int new) { struct perf_task_event task_event; if (!atomic_read(&nr_comm_events) && !atomic_read(&nr_mmap_events) && !atomic_read(&nr_task_events)) return; task_event = (struct perf_task_event){ .task = task, .task_ctx = task_ctx, .event_id = { .header = { .type = new ? PERF_RECORD_FORK : PERF_RECORD_EXIT, .misc = 0, .size = sizeof(task_event.event_id), }, /* .pid */ /* .ppid */ /* .tid */ /* .ptid */ .time = perf_clock(), }, }; perf_event_aux(perf_event_task_match, perf_event_task_output, &task_event, task_ctx); } void perf_event_fork(struct task_struct *task) { perf_event_task(task, NULL, 1); } /* * comm tracking */ struct perf_comm_event { struct task_struct *task; char *comm; int comm_size; struct { struct perf_event_header header; u32 pid; u32 tid; } event_id; }; static void perf_event_comm_output(struct perf_event *event, void *data) { struct perf_comm_event *comm_event = data; struct perf_output_handle handle; struct perf_sample_data sample; int size = comm_event->event_id.header.size; int ret; perf_event_header__init_id(&comm_event->event_id.header, &sample, event); ret = perf_output_begin(&handle, event, comm_event->event_id.header.size); if (ret) goto out; comm_event->event_id.pid = perf_event_pid(event, comm_event->task); comm_event->event_id.tid = perf_event_tid(event, comm_event->task); perf_output_put(&handle, comm_event->event_id); __output_copy(&handle, comm_event->comm, comm_event->comm_size); perf_event__output_id_sample(event, &handle, &sample); perf_output_end(&handle); out: comm_event->event_id.header.size = size; } static int perf_event_comm_match(struct perf_event *event, void *data __maybe_unused) { return event->attr.comm; } static void perf_event_comm_event(struct perf_comm_event *comm_event) { char comm[TASK_COMM_LEN]; unsigned int size; memset(comm, 0, sizeof(comm)); strlcpy(comm, comm_event->task->comm, sizeof(comm)); size = ALIGN(strlen(comm)+1, sizeof(u64)); comm_event->comm = comm; comm_event->comm_size = size; comm_event->event_id.header.size = sizeof(comm_event->event_id) + size; perf_event_aux(perf_event_comm_match, perf_event_comm_output, comm_event, NULL); } void perf_event_comm(struct task_struct *task) { struct perf_comm_event comm_event; struct perf_event_context *ctx; int ctxn; rcu_read_lock(); for_each_task_context_nr(ctxn) { ctx = task->perf_event_ctxp[ctxn]; if (!ctx) continue; perf_event_enable_on_exec(ctx); } rcu_read_unlock(); if (!atomic_read(&nr_comm_events)) return; comm_event = (struct perf_comm_event){ .task = task, /* .comm */ /* .comm_size */ .event_id = { .header = { .type = PERF_RECORD_COMM, .misc = 0, /* .size */ }, /* .pid */ /* .tid */ }, }; perf_event_comm_event(&comm_event); } /* * mmap tracking */ struct perf_mmap_event { struct vm_area_struct *vma; const char *file_name; int file_size; struct { struct perf_event_header header; u32 pid; u32 tid; u64 start; u64 len; u64 pgoff; } event_id; }; static void perf_event_mmap_output(struct perf_event *event, void *data) { struct perf_mmap_event *mmap_event = data; struct perf_output_handle handle; struct perf_sample_data sample; int size = mmap_event->event_id.header.size; int ret; perf_event_header__init_id(&mmap_event->event_id.header, &sample, event); ret = perf_output_begin(&handle, event, mmap_event->event_id.header.size); if (ret) goto out; mmap_event->event_id.pid = perf_event_pid(event, current); mmap_event->event_id.tid = perf_event_tid(event, current); perf_output_put(&handle, mmap_event->event_id); __output_copy(&handle, mmap_event->file_name, mmap_event->file_size); perf_event__output_id_sample(event, &handle, &sample); perf_output_end(&handle); out: mmap_event->event_id.header.size = size; } static int perf_event_mmap_match(struct perf_event *event, void *data) { struct perf_mmap_event *mmap_event = data; struct vm_area_struct *vma = mmap_event->vma; int executable = vma->vm_flags & VM_EXEC; return (!executable && event->attr.mmap_data) || (executable && event->attr.mmap); } static void perf_event_mmap_event(struct perf_mmap_event *mmap_event) { struct vm_area_struct *vma = mmap_event->vma; struct file *file = vma->vm_file; unsigned int size; char tmp[16]; char *buf = NULL; const char *name; memset(tmp, 0, sizeof(tmp)); if (file) { /* * d_path works from the end of the rb backwards, so we * need to add enough zero bytes after the string to handle * the 64bit alignment we do later. */ buf = kzalloc(PATH_MAX + sizeof(u64), GFP_KERNEL); if (!buf) { name = strncpy(tmp, "//enomem", sizeof(tmp)); goto got_name; } name = d_path(&file->f_path, buf, PATH_MAX); if (IS_ERR(name)) { name = strncpy(tmp, "//toolong", sizeof(tmp)); goto got_name; } } else { if (arch_vma_name(mmap_event->vma)) { name = strncpy(tmp, arch_vma_name(mmap_event->vma), sizeof(tmp) - 1); tmp[sizeof(tmp) - 1] = '\0'; goto got_name; } if (!vma->vm_mm) { name = strncpy(tmp, "[vdso]", sizeof(tmp)); goto got_name; } else if (vma->vm_start <= vma->vm_mm->start_brk && vma->vm_end >= vma->vm_mm->brk) { name = strncpy(tmp, "[heap]", sizeof(tmp)); goto got_name; } else if (vma->vm_start <= vma->vm_mm->start_stack && vma->vm_end >= vma->vm_mm->start_stack) { name = strncpy(tmp, "[stack]", sizeof(tmp)); goto got_name; } name = strncpy(tmp, "//anon", sizeof(tmp)); goto got_name; } got_name: size = ALIGN(strlen(name)+1, sizeof(u64)); mmap_event->file_name = name; mmap_event->file_size = size; if (!(vma->vm_flags & VM_EXEC)) mmap_event->event_id.header.misc |= PERF_RECORD_MISC_MMAP_DATA; mmap_event->event_id.header.size = sizeof(mmap_event->event_id) + size; perf_event_aux(perf_event_mmap_match, perf_event_mmap_output, mmap_event, NULL); kfree(buf); } void perf_event_mmap(struct vm_area_struct *vma) { struct perf_mmap_event mmap_event; if (!atomic_read(&nr_mmap_events)) return; mmap_event = (struct perf_mmap_event){ .vma = vma, /* .file_name */ /* .file_size */ .event_id = { .header = { .type = PERF_RECORD_MMAP, .misc = PERF_RECORD_MISC_USER, /* .size */ }, /* .pid */ /* .tid */ .start = vma->vm_start, .len = vma->vm_end - vma->vm_start, .pgoff = (u64)vma->vm_pgoff << PAGE_SHIFT, }, }; perf_event_mmap_event(&mmap_event); } /* * IRQ throttle logging */ static void perf_log_throttle(struct perf_event *event, int enable) { struct perf_output_handle handle; struct perf_sample_data sample; int ret; struct { struct perf_event_header header; u64 time; u64 id; u64 stream_id; } throttle_event = { .header = { .type = PERF_RECORD_THROTTLE, .misc = 0, .size = sizeof(throttle_event), }, .time = perf_clock(), .id = primary_event_id(event), .stream_id = event->id, }; if (enable) throttle_event.header.type = PERF_RECORD_UNTHROTTLE; perf_event_header__init_id(&throttle_event.header, &sample, event); ret = perf_output_begin(&handle, event, throttle_event.header.size); if (ret) return; perf_output_put(&handle, throttle_event); perf_event__output_id_sample(event, &handle, &sample); perf_output_end(&handle); } /* * Generic event overflow handling, sampling. */ static int __perf_event_overflow(struct perf_event *event, int throttle, struct perf_sample_data *data, struct pt_regs *regs) { int events = atomic_read(&event->event_limit); struct hw_perf_event *hwc = &event->hw; u64 seq; int ret = 0; /* * Non-sampling counters might still use the PMI to fold short * hardware counters, ignore those. */ if (unlikely(!is_sampling_event(event))) return 0; seq = __this_cpu_read(perf_throttled_seq); if (seq != hwc->interrupts_seq) { hwc->interrupts_seq = seq; hwc->interrupts = 1; } else { hwc->interrupts++; if (unlikely(throttle && hwc->interrupts >= max_samples_per_tick)) { __this_cpu_inc(perf_throttled_count); hwc->interrupts = MAX_INTERRUPTS; perf_log_throttle(event, 0); ret = 1; } } if (event->attr.freq) { u64 now = perf_clock(); s64 delta = now - hwc->freq_time_stamp; hwc->freq_time_stamp = now; if (delta > 0 && delta < 2*TICK_NSEC) perf_adjust_period(event, delta, hwc->last_period, true); } /* * XXX event_limit might not quite work as expected on inherited * events */ event->pending_kill = POLL_IN; if (events && atomic_dec_and_test(&event->event_limit)) { ret = 1; event->pending_kill = POLL_HUP; event->pending_disable = 1; irq_work_queue(&event->pending); } if (event->overflow_handler) event->overflow_handler(event, data, regs); else perf_event_output(event, data, regs); if (event->fasync && event->pending_kill) { event->pending_wakeup = 1; irq_work_queue(&event->pending); } return ret; } int perf_event_overflow(struct perf_event *event, struct perf_sample_data *data, struct pt_regs *regs) { return __perf_event_overflow(event, 1, data, regs); } /* * Generic software event infrastructure */ struct swevent_htable { struct swevent_hlist *swevent_hlist; struct mutex hlist_mutex; int hlist_refcount; /* Recursion avoidance in each contexts */ int recursion[PERF_NR_CONTEXTS]; /* Keeps track of cpu being initialized/exited */ bool online; }; static DEFINE_PER_CPU(struct swevent_htable, swevent_htable); /* * We directly increment event->count and keep a second value in * event->hw.period_left to count intervals. This period event * is kept in the range [-sample_period, 0] so that we can use the * sign as trigger. */ static u64 perf_swevent_set_period(struct perf_event *event) { struct hw_perf_event *hwc = &event->hw; u64 period = hwc->last_period; u64 nr, offset; s64 old, val; hwc->last_period = hwc->sample_period; again: old = val = local64_read(&hwc->period_left); if (val < 0) return 0; nr = div64_u64(period + val, period); offset = nr * period; val -= offset; if (local64_cmpxchg(&hwc->period_left, old, val) != old) goto again; return nr; } static void perf_swevent_overflow(struct perf_event *event, u64 overflow, struct perf_sample_data *data, struct pt_regs *regs) { struct hw_perf_event *hwc = &event->hw; int throttle = 0; if (!overflow) overflow = perf_swevent_set_period(event); if (hwc->interrupts == MAX_INTERRUPTS) return; for (; overflow; overflow--) { if (__perf_event_overflow(event, throttle, data, regs)) { /* * We inhibit the overflow from happening when * hwc->interrupts == MAX_INTERRUPTS. */ break; } throttle = 1; } } static void perf_swevent_event(struct perf_event *event, u64 nr, struct perf_sample_data *data, struct pt_regs *regs) { struct hw_perf_event *hwc = &event->hw; local64_add(nr, &event->count); if (!regs) return; if (!is_sampling_event(event)) return; if ((event->attr.sample_type & PERF_SAMPLE_PERIOD) && !event->attr.freq) { data->period = nr; return perf_swevent_overflow(event, 1, data, regs); } else data->period = event->hw.last_period; if (nr == 1 && hwc->sample_period == 1 && !event->attr.freq) return perf_swevent_overflow(event, 1, data, regs); if (local64_add_negative(nr, &hwc->period_left)) return; perf_swevent_overflow(event, 0, data, regs); } static int perf_exclude_event(struct perf_event *event, struct pt_regs *regs) { if (event->hw.state & PERF_HES_STOPPED) return 1; if (regs) { if (event->attr.exclude_user && user_mode(regs)) return 1; if (event->attr.exclude_kernel && !user_mode(regs)) return 1; } return 0; } static int perf_swevent_match(struct perf_event *event, enum perf_type_id type, u32 event_id, struct perf_sample_data *data, struct pt_regs *regs) { if (event->attr.type != type) return 0; if (event->attr.config != event_id) return 0; if (perf_exclude_event(event, regs)) return 0; return 1; } static inline u64 swevent_hash(u64 type, u32 event_id) { u64 val = event_id | (type << 32); return hash_64(val, SWEVENT_HLIST_BITS); } static inline struct hlist_head * __find_swevent_head(struct swevent_hlist *hlist, u64 type, u32 event_id) { u64 hash = swevent_hash(type, event_id); return &hlist->heads[hash]; } /* For the read side: events when they trigger */ static inline struct hlist_head * find_swevent_head_rcu(struct swevent_htable *swhash, u64 type, u32 event_id) { struct swevent_hlist *hlist; hlist = rcu_dereference(swhash->swevent_hlist); if (!hlist) return NULL; return __find_swevent_head(hlist, type, event_id); } /* For the event head insertion and removal in the hlist */ static inline struct hlist_head * find_swevent_head(struct swevent_htable *swhash, struct perf_event *event) { struct swevent_hlist *hlist; u32 event_id = event->attr.config; u64 type = event->attr.type; /* * Event scheduling is always serialized against hlist allocation * and release. Which makes the protected version suitable here. * The context lock guarantees that. */ hlist = rcu_dereference_protected(swhash->swevent_hlist, lockdep_is_held(&event->ctx->lock)); if (!hlist) return NULL; return __find_swevent_head(hlist, type, event_id); } static void do_perf_sw_event(enum perf_type_id type, u32 event_id, u64 nr, struct perf_sample_data *data, struct pt_regs *regs) { struct swevent_htable *swhash = &__get_cpu_var(swevent_htable); struct perf_event *event; struct hlist_head *head; rcu_read_lock(); head = find_swevent_head_rcu(swhash, type, event_id); if (!head) goto end; hlist_for_each_entry_rcu(event, head, hlist_entry) { if (perf_swevent_match(event, type, event_id, data, regs)) perf_swevent_event(event, nr, data, regs); } end: rcu_read_unlock(); } int perf_swevent_get_recursion_context(void) { struct swevent_htable *swhash = &__get_cpu_var(swevent_htable); return get_recursion_context(swhash->recursion); } EXPORT_SYMBOL_GPL(perf_swevent_get_recursion_context); inline void perf_swevent_put_recursion_context(int rctx) { struct swevent_htable *swhash = &__get_cpu_var(swevent_htable); put_recursion_context(swhash->recursion, rctx); } void __perf_sw_event(u32 event_id, u64 nr, struct pt_regs *regs, u64 addr) { struct perf_sample_data data; int rctx; preempt_disable_notrace(); rctx = perf_swevent_get_recursion_context(); if (rctx < 0) return; perf_sample_data_init(&data, addr, 0); do_perf_sw_event(PERF_TYPE_SOFTWARE, event_id, nr, &data, regs); perf_swevent_put_recursion_context(rctx); preempt_enable_notrace(); } static void perf_swevent_read(struct perf_event *event) { } static int perf_swevent_add(struct perf_event *event, int flags) { struct swevent_htable *swhash = &__get_cpu_var(swevent_htable); struct hw_perf_event *hwc = &event->hw; struct hlist_head *head; if (is_sampling_event(event)) { hwc->last_period = hwc->sample_period; perf_swevent_set_period(event); } hwc->state = !(flags & PERF_EF_START); head = find_swevent_head(swhash, event); if (!head) { /* * We can race with cpu hotplug code. Do not * WARN if the cpu just got unplugged. */ WARN_ON_ONCE(swhash->online); return -EINVAL; } hlist_add_head_rcu(&event->hlist_entry, head); return 0; } static void perf_swevent_del(struct perf_event *event, int flags) { hlist_del_rcu(&event->hlist_entry); } static void perf_swevent_start(struct perf_event *event, int flags) { event->hw.state = 0; } static void perf_swevent_stop(struct perf_event *event, int flags) { event->hw.state = PERF_HES_STOPPED; } /* Deref the hlist from the update side */ static inline struct swevent_hlist * swevent_hlist_deref(struct swevent_htable *swhash) { return rcu_dereference_protected(swhash->swevent_hlist, lockdep_is_held(&swhash->hlist_mutex)); } static void swevent_hlist_release(struct swevent_htable *swhash) { struct swevent_hlist *hlist = swevent_hlist_deref(swhash); if (!hlist) return; rcu_assign_pointer(swhash->swevent_hlist, NULL); kfree_rcu(hlist, rcu_head); } static void swevent_hlist_put_cpu(struct perf_event *event, int cpu) { struct swevent_htable *swhash = &per_cpu(swevent_htable, cpu); mutex_lock(&swhash->hlist_mutex); if (!--swhash->hlist_refcount) swevent_hlist_release(swhash); mutex_unlock(&swhash->hlist_mutex); } static void swevent_hlist_put(struct perf_event *event) { int cpu; if (event->cpu != -1) { swevent_hlist_put_cpu(event, event->cpu); return; } for_each_possible_cpu(cpu) swevent_hlist_put_cpu(event, cpu); } static int swevent_hlist_get_cpu(struct perf_event *event, int cpu) { struct swevent_htable *swhash = &per_cpu(swevent_htable, cpu); int err = 0; mutex_lock(&swhash->hlist_mutex); if (!swevent_hlist_deref(swhash) && cpu_online(cpu)) { struct swevent_hlist *hlist; hlist = kzalloc(sizeof(*hlist), GFP_KERNEL); if (!hlist) { err = -ENOMEM; goto exit; } rcu_assign_pointer(swhash->swevent_hlist, hlist); } swhash->hlist_refcount++; exit: mutex_unlock(&swhash->hlist_mutex); return err; } static int swevent_hlist_get(struct perf_event *event) { int err; int cpu, failed_cpu; if (event->cpu != -1) return swevent_hlist_get_cpu(event, event->cpu); get_online_cpus(); for_each_possible_cpu(cpu) { err = swevent_hlist_get_cpu(event, cpu); if (err) { failed_cpu = cpu; goto fail; } } put_online_cpus(); return 0; fail: for_each_possible_cpu(cpu) { if (cpu == failed_cpu) break; swevent_hlist_put_cpu(event, cpu); } put_online_cpus(); return err; } struct static_key perf_swevent_enabled[PERF_COUNT_SW_MAX]; static void sw_perf_event_destroy(struct perf_event *event) { u64 event_id = event->attr.config; WARN_ON(event->parent); static_key_slow_dec(&perf_swevent_enabled[event_id]); swevent_hlist_put(event); } static int perf_swevent_init(struct perf_event *event) { u64 event_id = event->attr.config; if (event->attr.type != PERF_TYPE_SOFTWARE) return -ENOENT; /* * no branch sampling for software events */ if (has_branch_stack(event)) return -EOPNOTSUPP; switch (event_id) { case PERF_COUNT_SW_CPU_CLOCK: case PERF_COUNT_SW_TASK_CLOCK: return -ENOENT; default: break; } if (event_id >= PERF_COUNT_SW_MAX) return -ENOENT; if (!event->parent) { int err; err = swevent_hlist_get(event); if (err) return err; static_key_slow_inc(&perf_swevent_enabled[event_id]); event->destroy = sw_perf_event_destroy; } return 0; } static int perf_swevent_event_idx(struct perf_event *event) { return 0; } static struct pmu perf_swevent = { .task_ctx_nr = perf_sw_context, .event_init = perf_swevent_init, .add = perf_swevent_add, .del = perf_swevent_del, .start = perf_swevent_start, .stop = perf_swevent_stop, .read = perf_swevent_read, .event_idx = perf_swevent_event_idx, }; #ifdef CONFIG_EVENT_TRACING static int perf_tp_filter_match(struct perf_event *event, struct perf_sample_data *data) { void *record = data->raw->data; if (likely(!event->filter) || filter_match_preds(event->filter, record)) return 1; return 0; } static int perf_tp_event_match(struct perf_event *event, struct perf_sample_data *data, struct pt_regs *regs) { if (event->hw.state & PERF_HES_STOPPED) return 0; /* * All tracepoints are from kernel-space. */ if (event->attr.exclude_kernel) return 0; if (!perf_tp_filter_match(event, data)) return 0; return 1; } void perf_tp_event(u64 addr, u64 count, void *record, int entry_size, struct pt_regs *regs, struct hlist_head *head, int rctx, struct task_struct *task) { struct perf_sample_data data; struct perf_event *event; struct perf_raw_record raw = { .size = entry_size, .data = record, }; perf_sample_data_init(&data, addr, 0); data.raw = &raw; hlist_for_each_entry_rcu(event, head, hlist_entry) { if (perf_tp_event_match(event, &data, regs)) perf_swevent_event(event, count, &data, regs); } /* * If we got specified a target task, also iterate its context and * deliver this event there too. */ if (task && task != current) { struct perf_event_context *ctx; struct trace_entry *entry = record; rcu_read_lock(); ctx = rcu_dereference(task->perf_event_ctxp[perf_sw_context]); if (!ctx) goto unlock; list_for_each_entry_rcu(event, &ctx->event_list, event_entry) { if (event->attr.type != PERF_TYPE_TRACEPOINT) continue; if (event->attr.config != entry->type) continue; if (perf_tp_event_match(event, &data, regs)) perf_swevent_event(event, count, &data, regs); } unlock: rcu_read_unlock(); } perf_swevent_put_recursion_context(rctx); } EXPORT_SYMBOL_GPL(perf_tp_event); static void tp_perf_event_destroy(struct perf_event *event) { perf_trace_destroy(event); } static int perf_tp_event_init(struct perf_event *event) { int err; if (event->attr.type != PERF_TYPE_TRACEPOINT) return -ENOENT; /* * no branch sampling for tracepoint events */ if (has_branch_stack(event)) return -EOPNOTSUPP; err = perf_trace_init(event); if (err) return err; event->destroy = tp_perf_event_destroy; return 0; } static struct pmu perf_tracepoint = { .task_ctx_nr = perf_sw_context, .event_init = perf_tp_event_init, .add = perf_trace_add, .del = perf_trace_del, .start = perf_swevent_start, .stop = perf_swevent_stop, .read = perf_swevent_read, .event_idx = perf_swevent_event_idx, }; static inline void perf_tp_register(void) { perf_pmu_register(&perf_tracepoint, "tracepoint", PERF_TYPE_TRACEPOINT); } static int perf_event_set_filter(struct perf_event *event, void __user *arg) { char *filter_str; int ret; if (event->attr.type != PERF_TYPE_TRACEPOINT) return -EINVAL; filter_str = strndup_user(arg, PAGE_SIZE); if (IS_ERR(filter_str)) return PTR_ERR(filter_str); ret = ftrace_profile_set_filter(event, event->attr.config, filter_str); kfree(filter_str); return ret; } static void perf_event_free_filter(struct perf_event *event) { ftrace_profile_free_filter(event); } #else static inline void perf_tp_register(void) { } static int perf_event_set_filter(struct perf_event *event, void __user *arg) { return -ENOENT; } static void perf_event_free_filter(struct perf_event *event) { } #endif /* CONFIG_EVENT_TRACING */ #ifdef CONFIG_HAVE_HW_BREAKPOINT void perf_bp_event(struct perf_event *bp, void *data) { struct perf_sample_data sample; struct pt_regs *regs = data; perf_sample_data_init(&sample, bp->attr.bp_addr, 0); if (!bp->hw.state && !perf_exclude_event(bp, regs)) perf_swevent_event(bp, 1, &sample, regs); } #endif /* * hrtimer based swevent callback */ static enum hrtimer_restart perf_swevent_hrtimer(struct hrtimer *hrtimer) { enum hrtimer_restart ret = HRTIMER_RESTART; struct perf_sample_data data; struct pt_regs *regs; struct perf_event *event; u64 period; event = container_of(hrtimer, struct perf_event, hw.hrtimer); if (event->state != PERF_EVENT_STATE_ACTIVE) return HRTIMER_NORESTART; event->pmu->read(event); perf_sample_data_init(&data, 0, event->hw.last_period); regs = get_irq_regs(); if (regs && !perf_exclude_event(event, regs)) { if (!(event->attr.exclude_idle && is_idle_task(current))) if (__perf_event_overflow(event, 1, &data, regs)) ret = HRTIMER_NORESTART; } period = max_t(u64, 10000, event->hw.sample_period); hrtimer_forward_now(hrtimer, ns_to_ktime(period)); return ret; } static void perf_swevent_start_hrtimer(struct perf_event *event) { struct hw_perf_event *hwc = &event->hw; s64 period; if (!is_sampling_event(event)) return; period = local64_read(&hwc->period_left); if (period) { if (period < 0) period = 10000; local64_set(&hwc->period_left, 0); } else { period = max_t(u64, 10000, hwc->sample_period); } __hrtimer_start_range_ns(&hwc->hrtimer, ns_to_ktime(period), 0, HRTIMER_MODE_REL_PINNED, 0); } static void perf_swevent_cancel_hrtimer(struct perf_event *event) { struct hw_perf_event *hwc = &event->hw; if (is_sampling_event(event)) { ktime_t remaining = hrtimer_get_remaining(&hwc->hrtimer); local64_set(&hwc->period_left, ktime_to_ns(remaining)); hrtimer_cancel(&hwc->hrtimer); } } static void perf_swevent_init_hrtimer(struct perf_event *event) { struct hw_perf_event *hwc = &event->hw; if (!is_sampling_event(event)) return; hrtimer_init(&hwc->hrtimer, CLOCK_MONOTONIC, HRTIMER_MODE_REL); hwc->hrtimer.function = perf_swevent_hrtimer; /* * Since hrtimers have a fixed rate, we can do a static freq->period * mapping and avoid the whole period adjust feedback stuff. */ if (event->attr.freq) { long freq = event->attr.sample_freq; event->attr.sample_period = NSEC_PER_SEC / freq; hwc->sample_period = event->attr.sample_period; local64_set(&hwc->period_left, hwc->sample_period); hwc->last_period = hwc->sample_period; event->attr.freq = 0; } } /* * Software event: cpu wall time clock */ static void cpu_clock_event_update(struct perf_event *event) { s64 prev; u64 now; now = local_clock(); prev = local64_xchg(&event->hw.prev_count, now); local64_add(now - prev, &event->count); } static void cpu_clock_event_start(struct perf_event *event, int flags) { local64_set(&event->hw.prev_count, local_clock()); perf_swevent_start_hrtimer(event); } static void cpu_clock_event_stop(struct perf_event *event, int flags) { perf_swevent_cancel_hrtimer(event); cpu_clock_event_update(event); } static int cpu_clock_event_add(struct perf_event *event, int flags) { if (flags & PERF_EF_START) cpu_clock_event_start(event, flags); return 0; } static void cpu_clock_event_del(struct perf_event *event, int flags) { cpu_clock_event_stop(event, flags); } static void cpu_clock_event_read(struct perf_event *event) { cpu_clock_event_update(event); } static int cpu_clock_event_init(struct perf_event *event) { if (event->attr.type != PERF_TYPE_SOFTWARE) return -ENOENT; if (event->attr.config != PERF_COUNT_SW_CPU_CLOCK) return -ENOENT; /* * no branch sampling for software events */ if (has_branch_stack(event)) return -EOPNOTSUPP; perf_swevent_init_hrtimer(event); return 0; } static struct pmu perf_cpu_clock = { .task_ctx_nr = perf_sw_context, .event_init = cpu_clock_event_init, .add = cpu_clock_event_add, .del = cpu_clock_event_del, .start = cpu_clock_event_start, .stop = cpu_clock_event_stop, .read = cpu_clock_event_read, .event_idx = perf_swevent_event_idx, }; /* * Software event: task time clock */ static void task_clock_event_update(struct perf_event *event, u64 now) { u64 prev; s64 delta; prev = local64_xchg(&event->hw.prev_count, now); delta = now - prev; local64_add(delta, &event->count); } static void task_clock_event_start(struct perf_event *event, int flags) { local64_set(&event->hw.prev_count, event->ctx->time); perf_swevent_start_hrtimer(event); } static void task_clock_event_stop(struct perf_event *event, int flags) { perf_swevent_cancel_hrtimer(event); task_clock_event_update(event, event->ctx->time); } static int task_clock_event_add(struct perf_event *event, int flags) { if (flags & PERF_EF_START) task_clock_event_start(event, flags); return 0; } static void task_clock_event_del(struct perf_event *event, int flags) { task_clock_event_stop(event, PERF_EF_UPDATE); } static void task_clock_event_read(struct perf_event *event) { u64 now = perf_clock(); u64 delta = now - event->ctx->timestamp; u64 time = event->ctx->time + delta; task_clock_event_update(event, time); } static int task_clock_event_init(struct perf_event *event) { if (event->attr.type != PERF_TYPE_SOFTWARE) return -ENOENT; if (event->attr.config != PERF_COUNT_SW_TASK_CLOCK) return -ENOENT; /* * no branch sampling for software events */ if (has_branch_stack(event)) return -EOPNOTSUPP; perf_swevent_init_hrtimer(event); return 0; } static struct pmu perf_task_clock = { .task_ctx_nr = perf_sw_context, .event_init = task_clock_event_init, .add = task_clock_event_add, .del = task_clock_event_del, .start = task_clock_event_start, .stop = task_clock_event_stop, .read = task_clock_event_read, .event_idx = perf_swevent_event_idx, }; static void perf_pmu_nop_void(struct pmu *pmu) { } static int perf_pmu_nop_int(struct pmu *pmu) { return 0; } static void perf_pmu_start_txn(struct pmu *pmu) { perf_pmu_disable(pmu); } static int perf_pmu_commit_txn(struct pmu *pmu) { perf_pmu_enable(pmu); return 0; } static void perf_pmu_cancel_txn(struct pmu *pmu) { perf_pmu_enable(pmu); } static int perf_event_idx_default(struct perf_event *event) { return event->hw.idx + 1; } /* * Ensures all contexts with the same task_ctx_nr have the same * pmu_cpu_context too. */ static void *find_pmu_context(int ctxn) { struct pmu *pmu; if (ctxn < 0) return NULL; list_for_each_entry(pmu, &pmus, entry) { if (pmu->task_ctx_nr == ctxn) return pmu->pmu_cpu_context; } return NULL; } static void update_pmu_context(struct pmu *pmu, struct pmu *old_pmu) { int cpu; for_each_possible_cpu(cpu) { struct perf_cpu_context *cpuctx; cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu); if (cpuctx->unique_pmu == old_pmu) cpuctx->unique_pmu = pmu; } } static void free_pmu_context(struct pmu *pmu) { struct pmu *i; mutex_lock(&pmus_lock); /* * Like a real lame refcount. */ list_for_each_entry(i, &pmus, entry) { if (i->pmu_cpu_context == pmu->pmu_cpu_context) { update_pmu_context(i, pmu); goto out; } } free_percpu(pmu->pmu_cpu_context); out: mutex_unlock(&pmus_lock); } static struct idr pmu_idr; static ssize_t type_show(struct device *dev, struct device_attribute *attr, char *page) { struct pmu *pmu = dev_get_drvdata(dev); return snprintf(page, PAGE_SIZE-1, "%d\n", pmu->type); } static struct device_attribute pmu_dev_attrs[] = { __ATTR_RO(type), __ATTR_NULL, }; static int pmu_bus_running; static struct bus_type pmu_bus = { .name = "event_source", .dev_attrs = pmu_dev_attrs, }; static void pmu_dev_release(struct device *dev) { kfree(dev); } static int pmu_dev_alloc(struct pmu *pmu) { int ret = -ENOMEM; pmu->dev = kzalloc(sizeof(struct device), GFP_KERNEL); if (!pmu->dev) goto out; pmu->dev->groups = pmu->attr_groups; device_initialize(pmu->dev); ret = dev_set_name(pmu->dev, "%s", pmu->name); if (ret) goto free_dev; dev_set_drvdata(pmu->dev, pmu); pmu->dev->bus = &pmu_bus; pmu->dev->release = pmu_dev_release; ret = device_add(pmu->dev); if (ret) goto free_dev; out: return ret; free_dev: put_device(pmu->dev); goto out; } static struct lock_class_key cpuctx_mutex; static struct lock_class_key cpuctx_lock; int perf_pmu_register(struct pmu *pmu, char *name, int type) { int cpu, ret; mutex_lock(&pmus_lock); ret = -ENOMEM; pmu->pmu_disable_count = alloc_percpu(int); if (!pmu->pmu_disable_count) goto unlock; pmu->type = -1; if (!name) goto skip_type; pmu->name = name; if (type < 0) { type = idr_alloc(&pmu_idr, pmu, PERF_TYPE_MAX, 0, GFP_KERNEL); if (type < 0) { ret = type; goto free_pdc; } } pmu->type = type; if (pmu_bus_running) { ret = pmu_dev_alloc(pmu); if (ret) goto free_idr; } skip_type: pmu->pmu_cpu_context = find_pmu_context(pmu->task_ctx_nr); if (pmu->pmu_cpu_context) goto got_cpu_context; ret = -ENOMEM; pmu->pmu_cpu_context = alloc_percpu(struct perf_cpu_context); if (!pmu->pmu_cpu_context) goto free_dev; for_each_possible_cpu(cpu) { struct perf_cpu_context *cpuctx; cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu); __perf_event_init_context(&cpuctx->ctx); lockdep_set_class(&cpuctx->ctx.mutex, &cpuctx_mutex); lockdep_set_class(&cpuctx->ctx.lock, &cpuctx_lock); cpuctx->ctx.type = cpu_context; cpuctx->ctx.pmu = pmu; cpuctx->jiffies_interval = 1; INIT_LIST_HEAD(&cpuctx->rotation_list); cpuctx->unique_pmu = pmu; } got_cpu_context: if (!pmu->start_txn) { if (pmu->pmu_enable) { /* * If we have pmu_enable/pmu_disable calls, install * transaction stubs that use that to try and batch * hardware accesses. */ pmu->start_txn = perf_pmu_start_txn; pmu->commit_txn = perf_pmu_commit_txn; pmu->cancel_txn = perf_pmu_cancel_txn; } else { pmu->start_txn = perf_pmu_nop_void; pmu->commit_txn = perf_pmu_nop_int; pmu->cancel_txn = perf_pmu_nop_void; } } if (!pmu->pmu_enable) { pmu->pmu_enable = perf_pmu_nop_void; pmu->pmu_disable = perf_pmu_nop_void; } if (!pmu->event_idx) pmu->event_idx = perf_event_idx_default; list_add_rcu(&pmu->entry, &pmus); ret = 0; unlock: mutex_unlock(&pmus_lock); return ret; free_dev: device_del(pmu->dev); put_device(pmu->dev); free_idr: if (pmu->type >= PERF_TYPE_MAX) idr_remove(&pmu_idr, pmu->type); free_pdc: free_percpu(pmu->pmu_disable_count); goto unlock; } void perf_pmu_unregister(struct pmu *pmu) { mutex_lock(&pmus_lock); list_del_rcu(&pmu->entry); mutex_unlock(&pmus_lock); /* * We dereference the pmu list under both SRCU and regular RCU, so * synchronize against both of those. */ synchronize_srcu(&pmus_srcu); synchronize_rcu(); free_percpu(pmu->pmu_disable_count); if (pmu->type >= PERF_TYPE_MAX) idr_remove(&pmu_idr, pmu->type); device_del(pmu->dev); put_device(pmu->dev); free_pmu_context(pmu); } struct pmu *perf_init_event(struct perf_event *event) { struct pmu *pmu = NULL; int idx; int ret; idx = srcu_read_lock(&pmus_srcu); rcu_read_lock(); pmu = idr_find(&pmu_idr, event->attr.type); rcu_read_unlock(); if (pmu) { event->pmu = pmu; ret = pmu->event_init(event); if (ret) pmu = ERR_PTR(ret); goto unlock; } list_for_each_entry_rcu(pmu, &pmus, entry) { event->pmu = pmu; ret = pmu->event_init(event); if (!ret) goto unlock; if (ret != -ENOENT) { pmu = ERR_PTR(ret); goto unlock; } } pmu = ERR_PTR(-ENOENT); unlock: srcu_read_unlock(&pmus_srcu, idx); return pmu; } /* * Allocate and initialize a event structure */ static struct perf_event * perf_event_alloc(struct perf_event_attr *attr, int cpu, struct task_struct *task, struct perf_event *group_leader, struct perf_event *parent_event, perf_overflow_handler_t overflow_handler, void *context) { struct pmu *pmu; struct perf_event *event; struct hw_perf_event *hwc; long err; if ((unsigned)cpu >= nr_cpu_ids) { if (!task || cpu != -1) return ERR_PTR(-EINVAL); } event = kzalloc(sizeof(*event), GFP_KERNEL); if (!event) return ERR_PTR(-ENOMEM); /* * Single events are their own group leaders, with an * empty sibling list: */ if (!group_leader) group_leader = event; mutex_init(&event->child_mutex); INIT_LIST_HEAD(&event->child_list); INIT_LIST_HEAD(&event->group_entry); INIT_LIST_HEAD(&event->event_entry); INIT_LIST_HEAD(&event->sibling_list); INIT_LIST_HEAD(&event->rb_entry); init_waitqueue_head(&event->waitq); init_irq_work(&event->pending, perf_pending_event); mutex_init(&event->mmap_mutex); atomic_long_set(&event->refcount, 1); event->cpu = cpu; event->attr = *attr; event->group_leader = group_leader; event->pmu = NULL; event->oncpu = -1; event->parent = parent_event; event->ns = get_pid_ns(task_active_pid_ns(current)); event->id = atomic64_inc_return(&perf_event_id); event->state = PERF_EVENT_STATE_INACTIVE; if (task) { event->attach_state = PERF_ATTACH_TASK; if (attr->type == PERF_TYPE_TRACEPOINT) event->hw.tp_target = task; #ifdef CONFIG_HAVE_HW_BREAKPOINT /* * hw_breakpoint is a bit difficult here.. */ else if (attr->type == PERF_TYPE_BREAKPOINT) event->hw.bp_target = task; #endif } if (!overflow_handler && parent_event) { overflow_handler = parent_event->overflow_handler; context = parent_event->overflow_handler_context; } event->overflow_handler = overflow_handler; event->overflow_handler_context = context; perf_event__state_init(event); pmu = NULL; hwc = &event->hw; hwc->sample_period = attr->sample_period; if (attr->freq && attr->sample_freq) hwc->sample_period = 1; hwc->last_period = hwc->sample_period; local64_set(&hwc->period_left, hwc->sample_period); /* * we currently do not support PERF_FORMAT_GROUP on inherited events */ if (attr->inherit && (attr->read_format & PERF_FORMAT_GROUP)) goto done; pmu = perf_init_event(event); done: err = 0; if (!pmu) err = -EINVAL; else if (IS_ERR(pmu)) err = PTR_ERR(pmu); if (err) { if (event->ns) put_pid_ns(event->ns); kfree(event); return ERR_PTR(err); } if (!event->parent) { if (event->attach_state & PERF_ATTACH_TASK) static_key_slow_inc(&perf_sched_events.key); if (event->attr.mmap || event->attr.mmap_data) atomic_inc(&nr_mmap_events); if (event->attr.comm) atomic_inc(&nr_comm_events); if (event->attr.task) atomic_inc(&nr_task_events); if (event->attr.sample_type & PERF_SAMPLE_CALLCHAIN) { err = get_callchain_buffers(); if (err) { free_event(event); return ERR_PTR(err); } } if (has_branch_stack(event)) { static_key_slow_inc(&perf_sched_events.key); if (!(event->attach_state & PERF_ATTACH_TASK)) atomic_inc(&per_cpu(perf_branch_stack_events, event->cpu)); } } return event; } static int perf_copy_attr(struct perf_event_attr __user *uattr, struct perf_event_attr *attr) { u32 size; int ret; if (!access_ok(VERIFY_WRITE, uattr, PERF_ATTR_SIZE_VER0)) return -EFAULT; /* * zero the full structure, so that a short copy will be nice. */ memset(attr, 0, sizeof(*attr)); ret = get_user(size, &uattr->size); if (ret) return ret; if (size > PAGE_SIZE) /* silly large */ goto err_size; if (!size) /* abi compat */ size = PERF_ATTR_SIZE_VER0; if (size < PERF_ATTR_SIZE_VER0) goto err_size; /* * If we're handed a bigger struct than we know of, * ensure all the unknown bits are 0 - i.e. new * user-space does not rely on any kernel feature * extensions we dont know about yet. */ if (size > sizeof(*attr)) { unsigned char __user *addr; unsigned char __user *end; unsigned char val; addr = (void __user *)uattr + sizeof(*attr); end = (void __user *)uattr + size; for (; addr < end; addr++) { ret = get_user(val, addr); if (ret) return ret; if (val) goto err_size; } size = sizeof(*attr); } ret = copy_from_user(attr, uattr, size); if (ret) return -EFAULT; if (attr->__reserved_1) return -EINVAL; if (attr->sample_type & ~(PERF_SAMPLE_MAX-1)) return -EINVAL; if (attr->read_format & ~(PERF_FORMAT_MAX-1)) return -EINVAL; if (attr->sample_type & PERF_SAMPLE_BRANCH_STACK) { u64 mask = attr->branch_sample_type; /* only using defined bits */ if (mask & ~(PERF_SAMPLE_BRANCH_MAX-1)) return -EINVAL; /* at least one branch bit must be set */ if (!(mask & ~PERF_SAMPLE_BRANCH_PLM_ALL)) return -EINVAL; /* kernel level capture: check permissions */ if ((mask & PERF_SAMPLE_BRANCH_PERM_PLM) && perf_paranoid_kernel() && !capable(CAP_SYS_ADMIN)) return -EACCES; /* propagate priv level, when not set for branch */ if (!(mask & PERF_SAMPLE_BRANCH_PLM_ALL)) { /* exclude_kernel checked on syscall entry */ if (!attr->exclude_kernel) mask |= PERF_SAMPLE_BRANCH_KERNEL; if (!attr->exclude_user) mask |= PERF_SAMPLE_BRANCH_USER; if (!attr->exclude_hv) mask |= PERF_SAMPLE_BRANCH_HV; /* * adjust user setting (for HW filter setup) */ attr->branch_sample_type = mask; } } if (attr->sample_type & PERF_SAMPLE_REGS_USER) { ret = perf_reg_validate(attr->sample_regs_user); if (ret) return ret; } if (attr->sample_type & PERF_SAMPLE_STACK_USER) { if (!arch_perf_have_user_stack_dump()) return -ENOSYS; /* * We have __u32 type for the size, but so far * we can only use __u16 as maximum due to the * __u16 sample size limit. */ if (attr->sample_stack_user >= USHRT_MAX) ret = -EINVAL; else if (!IS_ALIGNED(attr->sample_stack_user, sizeof(u64))) ret = -EINVAL; } out: return ret; err_size: put_user(sizeof(*attr), &uattr->size); ret = -E2BIG; goto out; } static int perf_event_set_output(struct perf_event *event, struct perf_event *output_event) { struct ring_buffer *rb = NULL, *old_rb = NULL; int ret = -EINVAL; if (!output_event) goto set; /* don't allow circular references */ if (event == output_event) goto out; /* * Don't allow cross-cpu buffers */ if (output_event->cpu != event->cpu) goto out; /* * If its not a per-cpu rb, it must be the same task. */ if (output_event->cpu == -1 && output_event->ctx != event->ctx) goto out; set: mutex_lock(&event->mmap_mutex); /* Can't redirect output if we've got an active mmap() */ if (atomic_read(&event->mmap_count)) goto unlock; old_rb = event->rb; if (output_event) { /* get the rb we want to redirect to */ rb = ring_buffer_get(output_event); if (!rb) goto unlock; } if (old_rb) ring_buffer_detach(event, old_rb); if (rb) ring_buffer_attach(event, rb); rcu_assign_pointer(event->rb, rb); if (old_rb) { ring_buffer_put(old_rb); /* * Since we detached before setting the new rb, so that we * could attach the new rb, we could have missed a wakeup. * Provide it now. */ wake_up_all(&event->waitq); } ret = 0; unlock: mutex_unlock(&event->mmap_mutex); out: return ret; } /** * sys_perf_event_open - open a performance event, associate it to a task/cpu * * @attr_uptr: event_id type attributes for monitoring/sampling * @pid: target pid * @cpu: target cpu * @group_fd: group leader event fd */ SYSCALL_DEFINE5(perf_event_open, struct perf_event_attr __user *, attr_uptr, pid_t, pid, int, cpu, int, group_fd, unsigned long, flags) { struct perf_event *group_leader = NULL, *output_event = NULL; struct perf_event *event, *sibling; struct perf_event_attr attr; struct perf_event_context *ctx; struct file *event_file = NULL; struct fd group = {NULL, 0}; struct task_struct *task = NULL; struct pmu *pmu; int event_fd; int move_group = 0; int err; /* for future expandability... */ if (flags & ~PERF_FLAG_ALL) return -EINVAL; err = perf_copy_attr(attr_uptr, &attr); if (err) return err; if (!attr.exclude_kernel) { if (perf_paranoid_kernel() && !capable(CAP_SYS_ADMIN)) return -EACCES; } if (attr.freq) { if (attr.sample_freq > sysctl_perf_event_sample_rate) return -EINVAL; } else { if (attr.sample_period & (1ULL << 63)) return -EINVAL; } /* * In cgroup mode, the pid argument is used to pass the fd * opened to the cgroup directory in cgroupfs. The cpu argument * designates the cpu on which to monitor threads from that * cgroup. */ if ((flags & PERF_FLAG_PID_CGROUP) && (pid == -1 || cpu == -1)) return -EINVAL; event_fd = get_unused_fd(); if (event_fd < 0) return event_fd; if (group_fd != -1) { err = perf_fget_light(group_fd, &group); if (err) goto err_fd; group_leader = group.file->private_data; if (flags & PERF_FLAG_FD_OUTPUT) output_event = group_leader; if (flags & PERF_FLAG_FD_NO_GROUP) group_leader = NULL; } if (pid != -1 && !(flags & PERF_FLAG_PID_CGROUP)) { task = find_lively_task_by_vpid(pid); if (IS_ERR(task)) { err = PTR_ERR(task); goto err_group_fd; } } get_online_cpus(); event = perf_event_alloc(&attr, cpu, task, group_leader, NULL, NULL, NULL); if (IS_ERR(event)) { err = PTR_ERR(event); goto err_task; } if (flags & PERF_FLAG_PID_CGROUP) { err = perf_cgroup_connect(pid, event, &attr, group_leader); if (err) goto err_alloc; /* * one more event: * - that has cgroup constraint on event->cpu * - that may need work on context switch */ atomic_inc(&per_cpu(perf_cgroup_events, event->cpu)); static_key_slow_inc(&perf_sched_events.key); } /* * Special case software events and allow them to be part of * any hardware group. */ pmu = event->pmu; if (group_leader && (is_software_event(event) != is_software_event(group_leader))) { if (is_software_event(event)) { /* * If event and group_leader are not both a software * event, and event is, then group leader is not. * * Allow the addition of software events to !software * groups, this is safe because software events never * fail to schedule. */ pmu = group_leader->pmu; } else if (is_software_event(group_leader) && (group_leader->group_flags & PERF_GROUP_SOFTWARE)) { /* * In case the group is a pure software group, and we * try to add a hardware event, move the whole group to * the hardware context. */ move_group = 1; } } /* * Get the target context (task or percpu): */ ctx = find_get_context(pmu, task, event->cpu); if (IS_ERR(ctx)) { err = PTR_ERR(ctx); goto err_alloc; } if (task) { put_task_struct(task); task = NULL; } /* * Look up the group leader (we will attach this event to it): */ if (group_leader) { err = -EINVAL; /* * Do not allow a recursive hierarchy (this new sibling * becoming part of another group-sibling): */ if (group_leader->group_leader != group_leader) goto err_context; /* * Do not allow to attach to a group in a different * task or CPU context: */ if (move_group) { if (group_leader->ctx->type != ctx->type) goto err_context; } else { if (group_leader->ctx != ctx) goto err_context; } /* * Only a group leader can be exclusive or pinned */ if (attr.exclusive || attr.pinned) goto err_context; } if (output_event) { err = perf_event_set_output(event, output_event); if (err) goto err_context; } event_file = anon_inode_getfile("[perf_event]", &perf_fops, event, O_RDWR); if (IS_ERR(event_file)) { err = PTR_ERR(event_file); goto err_context; } if (move_group) { struct perf_event_context *gctx = group_leader->ctx; mutex_lock(&gctx->mutex); perf_remove_from_context(group_leader, false); /* * Removing from the context ends up with disabled * event. What we want here is event in the initial * startup state, ready to be add into new context. */ perf_event__state_init(group_leader); list_for_each_entry(sibling, &group_leader->sibling_list, group_entry) { perf_remove_from_context(sibling, false); perf_event__state_init(sibling); put_ctx(gctx); } mutex_unlock(&gctx->mutex); put_ctx(gctx); } WARN_ON_ONCE(ctx->parent_ctx); mutex_lock(&ctx->mutex); if (move_group) { synchronize_rcu(); perf_install_in_context(ctx, group_leader, group_leader->cpu); get_ctx(ctx); list_for_each_entry(sibling, &group_leader->sibling_list, group_entry) { perf_install_in_context(ctx, sibling, sibling->cpu); get_ctx(ctx); } } perf_install_in_context(ctx, event, event->cpu); ++ctx->generation; perf_unpin_context(ctx); mutex_unlock(&ctx->mutex); put_online_cpus(); event->owner = current; mutex_lock(¤t->perf_event_mutex); list_add_tail(&event->owner_entry, ¤t->perf_event_list); mutex_unlock(¤t->perf_event_mutex); /* * Precalculate sample_data sizes */ perf_event__header_size(event); perf_event__id_header_size(event); /* * Drop the reference on the group_event after placing the * new event on the sibling_list. This ensures destruction * of the group leader will find the pointer to itself in * perf_group_detach(). */ fdput(group); fd_install(event_fd, event_file); return event_fd; err_context: perf_unpin_context(ctx); put_ctx(ctx); err_alloc: free_event(event); err_task: put_online_cpus(); if (task) put_task_struct(task); err_group_fd: fdput(group); err_fd: put_unused_fd(event_fd); return err; } /** * perf_event_create_kernel_counter * * @attr: attributes of the counter to create * @cpu: cpu in which the counter is bound * @task: task to profile (NULL for percpu) */ struct perf_event * perf_event_create_kernel_counter(struct perf_event_attr *attr, int cpu, struct task_struct *task, perf_overflow_handler_t overflow_handler, void *context) { struct perf_event_context *ctx; struct perf_event *event; int err; /* * Get the target context (task or percpu): */ event = perf_event_alloc(attr, cpu, task, NULL, NULL, overflow_handler, context); if (IS_ERR(event)) { err = PTR_ERR(event); goto err; } ctx = find_get_context(event->pmu, task, cpu); if (IS_ERR(ctx)) { err = PTR_ERR(ctx); goto err_free; } WARN_ON_ONCE(ctx->parent_ctx); mutex_lock(&ctx->mutex); perf_install_in_context(ctx, event, cpu); ++ctx->generation; perf_unpin_context(ctx); mutex_unlock(&ctx->mutex); return event; err_free: free_event(event); err: return ERR_PTR(err); } EXPORT_SYMBOL_GPL(perf_event_create_kernel_counter); void perf_pmu_migrate_context(struct pmu *pmu, int src_cpu, int dst_cpu) { struct perf_event_context *src_ctx; struct perf_event_context *dst_ctx; struct perf_event *event, *tmp; LIST_HEAD(events); src_ctx = &per_cpu_ptr(pmu->pmu_cpu_context, src_cpu)->ctx; dst_ctx = &per_cpu_ptr(pmu->pmu_cpu_context, dst_cpu)->ctx; mutex_lock(&src_ctx->mutex); list_for_each_entry_safe(event, tmp, &src_ctx->event_list, event_entry) { perf_remove_from_context(event, false); put_ctx(src_ctx); list_add(&event->event_entry, &events); } mutex_unlock(&src_ctx->mutex); synchronize_rcu(); mutex_lock(&dst_ctx->mutex); list_for_each_entry_safe(event, tmp, &events, event_entry) { list_del(&event->event_entry); if (event->state >= PERF_EVENT_STATE_OFF) event->state = PERF_EVENT_STATE_INACTIVE; perf_install_in_context(dst_ctx, event, dst_cpu); get_ctx(dst_ctx); } mutex_unlock(&dst_ctx->mutex); } EXPORT_SYMBOL_GPL(perf_pmu_migrate_context); static void sync_child_event(struct perf_event *child_event, struct task_struct *child) { struct perf_event *parent_event = child_event->parent; u64 child_val; if (child_event->attr.inherit_stat) perf_event_read_event(child_event, child); child_val = perf_event_count(child_event); /* * Add back the child's count to the parent's count: */ atomic64_add(child_val, &parent_event->child_count); atomic64_add(child_event->total_time_enabled, &parent_event->child_total_time_enabled); atomic64_add(child_event->total_time_running, &parent_event->child_total_time_running); /* * Remove this event from the parent's list */ WARN_ON_ONCE(parent_event->ctx->parent_ctx); mutex_lock(&parent_event->child_mutex); list_del_init(&child_event->child_list); mutex_unlock(&parent_event->child_mutex); /* * Release the parent event, if this was the last * reference to it. */ put_event(parent_event); } static void __perf_event_exit_task(struct perf_event *child_event, struct perf_event_context *child_ctx, struct task_struct *child) { perf_remove_from_context(child_event, !!child_event->parent); /* * It can happen that the parent exits first, and has events * that are still around due to the child reference. These * events need to be zapped. */ if (child_event->parent) { sync_child_event(child_event, child); free_event(child_event); } } static void perf_event_exit_task_context(struct task_struct *child, int ctxn) { struct perf_event *child_event, *tmp; struct perf_event_context *child_ctx; unsigned long flags; if (likely(!child->perf_event_ctxp[ctxn])) { perf_event_task(child, NULL, 0); return; } local_irq_save(flags); /* * We can't reschedule here because interrupts are disabled, * and either child is current or it is a task that can't be * scheduled, so we are now safe from rescheduling changing * our context. */ child_ctx = rcu_dereference_raw(child->perf_event_ctxp[ctxn]); /* * Take the context lock here so that if find_get_context is * reading child->perf_event_ctxp, we wait until it has * incremented the context's refcount before we do put_ctx below. */ raw_spin_lock(&child_ctx->lock); task_ctx_sched_out(child_ctx); child->perf_event_ctxp[ctxn] = NULL; /* * If this context is a clone; unclone it so it can't get * swapped to another process while we're removing all * the events from it. */ unclone_ctx(child_ctx); update_context_time(child_ctx); raw_spin_unlock_irqrestore(&child_ctx->lock, flags); /* * Report the task dead after unscheduling the events so that we * won't get any samples after PERF_RECORD_EXIT. We can however still * get a few PERF_RECORD_READ events. */ perf_event_task(child, child_ctx, 0); /* * We can recurse on the same lock type through: * * __perf_event_exit_task() * sync_child_event() * put_event() * mutex_lock(&ctx->mutex) * * But since its the parent context it won't be the same instance. */ mutex_lock(&child_ctx->mutex); again: list_for_each_entry_safe(child_event, tmp, &child_ctx->pinned_groups, group_entry) __perf_event_exit_task(child_event, child_ctx, child); list_for_each_entry_safe(child_event, tmp, &child_ctx->flexible_groups, group_entry) __perf_event_exit_task(child_event, child_ctx, child); /* * If the last event was a group event, it will have appended all * its siblings to the list, but we obtained 'tmp' before that which * will still point to the list head terminating the iteration. */ if (!list_empty(&child_ctx->pinned_groups) || !list_empty(&child_ctx->flexible_groups)) goto again; mutex_unlock(&child_ctx->mutex); put_ctx(child_ctx); } /* * When a child task exits, feed back event values to parent events. */ void perf_event_exit_task(struct task_struct *child) { struct perf_event *event, *tmp; int ctxn; mutex_lock(&child->perf_event_mutex); list_for_each_entry_safe(event, tmp, &child->perf_event_list, owner_entry) { list_del_init(&event->owner_entry); /* * Ensure the list deletion is visible before we clear * the owner, closes a race against perf_release() where * we need to serialize on the owner->perf_event_mutex. */ smp_wmb(); event->owner = NULL; } mutex_unlock(&child->perf_event_mutex); for_each_task_context_nr(ctxn) perf_event_exit_task_context(child, ctxn); } static void perf_free_event(struct perf_event *event, struct perf_event_context *ctx) { struct perf_event *parent = event->parent; if (WARN_ON_ONCE(!parent)) return; mutex_lock(&parent->child_mutex); list_del_init(&event->child_list); mutex_unlock(&parent->child_mutex); put_event(parent); perf_group_detach(event); list_del_event(event, ctx); free_event(event); } /* * free an unexposed, unused context as created by inheritance by * perf_event_init_task below, used by fork() in case of fail. */ void perf_event_free_task(struct task_struct *task) { struct perf_event_context *ctx; struct perf_event *event, *tmp; int ctxn; for_each_task_context_nr(ctxn) { ctx = task->perf_event_ctxp[ctxn]; if (!ctx) continue; mutex_lock(&ctx->mutex); again: list_for_each_entry_safe(event, tmp, &ctx->pinned_groups, group_entry) perf_free_event(event, ctx); list_for_each_entry_safe(event, tmp, &ctx->flexible_groups, group_entry) perf_free_event(event, ctx); if (!list_empty(&ctx->pinned_groups) || !list_empty(&ctx->flexible_groups)) goto again; mutex_unlock(&ctx->mutex); put_ctx(ctx); } } void perf_event_delayed_put(struct task_struct *task) { int ctxn; for_each_task_context_nr(ctxn) WARN_ON_ONCE(task->perf_event_ctxp[ctxn]); } /* * inherit a event from parent task to child task: */ static struct perf_event * inherit_event(struct perf_event *parent_event, struct task_struct *parent, struct perf_event_context *parent_ctx, struct task_struct *child, struct perf_event *group_leader, struct perf_event_context *child_ctx) { struct perf_event *child_event; unsigned long flags; /* * Instead of creating recursive hierarchies of events, * we link inherited events back to the original parent, * which has a filp for sure, which we use as the reference * count: */ if (parent_event->parent) parent_event = parent_event->parent; child_event = perf_event_alloc(&parent_event->attr, parent_event->cpu, child, group_leader, parent_event, NULL, NULL); if (IS_ERR(child_event)) return child_event; if (!atomic_long_inc_not_zero(&parent_event->refcount)) { free_event(child_event); return NULL; } get_ctx(child_ctx); /* * Make the child state follow the state of the parent event, * not its attr.disabled bit. We hold the parent's mutex, * so we won't race with perf_event_{en, dis}able_family. */ if (parent_event->state >= PERF_EVENT_STATE_INACTIVE) child_event->state = PERF_EVENT_STATE_INACTIVE; else child_event->state = PERF_EVENT_STATE_OFF; if (parent_event->attr.freq) { u64 sample_period = parent_event->hw.sample_period; struct hw_perf_event *hwc = &child_event->hw; hwc->sample_period = sample_period; hwc->last_period = sample_period; local64_set(&hwc->period_left, sample_period); } child_event->ctx = child_ctx; child_event->overflow_handler = parent_event->overflow_handler; child_event->overflow_handler_context = parent_event->overflow_handler_context; /* * Precalculate sample_data sizes */ perf_event__header_size(child_event); perf_event__id_header_size(child_event); /* * Link it up in the child's context: */ raw_spin_lock_irqsave(&child_ctx->lock, flags); add_event_to_ctx(child_event, child_ctx); raw_spin_unlock_irqrestore(&child_ctx->lock, flags); /* * Link this into the parent event's child list */ WARN_ON_ONCE(parent_event->ctx->parent_ctx); mutex_lock(&parent_event->child_mutex); list_add_tail(&child_event->child_list, &parent_event->child_list); mutex_unlock(&parent_event->child_mutex); return child_event; } static int inherit_group(struct perf_event *parent_event, struct task_struct *parent, struct perf_event_context *parent_ctx, struct task_struct *child, struct perf_event_context *child_ctx) { struct perf_event *leader; struct perf_event *sub; struct perf_event *child_ctr; leader = inherit_event(parent_event, parent, parent_ctx, child, NULL, child_ctx); if (IS_ERR(leader)) return PTR_ERR(leader); list_for_each_entry(sub, &parent_event->sibling_list, group_entry) { child_ctr = inherit_event(sub, parent, parent_ctx, child, leader, child_ctx); if (IS_ERR(child_ctr)) return PTR_ERR(child_ctr); } return 0; } static int inherit_task_group(struct perf_event *event, struct task_struct *parent, struct perf_event_context *parent_ctx, struct task_struct *child, int ctxn, int *inherited_all) { int ret; struct perf_event_context *child_ctx; if (!event->attr.inherit) { *inherited_all = 0; return 0; } child_ctx = child->perf_event_ctxp[ctxn]; if (!child_ctx) { /* * This is executed from the parent task context, so * inherit events that have been marked for cloning. * First allocate and initialize a context for the * child. */ child_ctx = alloc_perf_context(parent_ctx->pmu, child); if (!child_ctx) return -ENOMEM; child->perf_event_ctxp[ctxn] = child_ctx; } ret = inherit_group(event, parent, parent_ctx, child, child_ctx); if (ret) *inherited_all = 0; return ret; } /* * Initialize the perf_event context in task_struct */ int perf_event_init_context(struct task_struct *child, int ctxn) { struct perf_event_context *child_ctx, *parent_ctx; struct perf_event_context *cloned_ctx; struct perf_event *event; struct task_struct *parent = current; int inherited_all = 1; unsigned long flags; int ret = 0; if (likely(!parent->perf_event_ctxp[ctxn])) return 0; /* * If the parent's context is a clone, pin it so it won't get * swapped under us. */ parent_ctx = perf_pin_task_context(parent, ctxn); /* * No need to check if parent_ctx != NULL here; since we saw * it non-NULL earlier, the only reason for it to become NULL * is if we exit, and since we're currently in the middle of * a fork we can't be exiting at the same time. */ /* * Lock the parent list. No need to lock the child - not PID * hashed yet and not running, so nobody can access it. */ mutex_lock(&parent_ctx->mutex); /* * We dont have to disable NMIs - we are only looking at * the list, not manipulating it: */ list_for_each_entry(event, &parent_ctx->pinned_groups, group_entry) { ret = inherit_task_group(event, parent, parent_ctx, child, ctxn, &inherited_all); if (ret) break; } /* * We can't hold ctx->lock when iterating the ->flexible_group list due * to allocations, but we need to prevent rotation because * rotate_ctx() will change the list from interrupt context. */ raw_spin_lock_irqsave(&parent_ctx->lock, flags); parent_ctx->rotate_disable = 1; raw_spin_unlock_irqrestore(&parent_ctx->lock, flags); list_for_each_entry(event, &parent_ctx->flexible_groups, group_entry) { ret = inherit_task_group(event, parent, parent_ctx, child, ctxn, &inherited_all); if (ret) break; } raw_spin_lock_irqsave(&parent_ctx->lock, flags); parent_ctx->rotate_disable = 0; child_ctx = child->perf_event_ctxp[ctxn]; if (child_ctx && inherited_all) { /* * Mark the child context as a clone of the parent * context, or of whatever the parent is a clone of. * * Note that if the parent is a clone, the holding of * parent_ctx->lock avoids it from being uncloned. */ cloned_ctx = parent_ctx->parent_ctx; if (cloned_ctx) { child_ctx->parent_ctx = cloned_ctx; child_ctx->parent_gen = parent_ctx->parent_gen; } else { child_ctx->parent_ctx = parent_ctx; child_ctx->parent_gen = parent_ctx->generation; } get_ctx(child_ctx->parent_ctx); } raw_spin_unlock_irqrestore(&parent_ctx->lock, flags); mutex_unlock(&parent_ctx->mutex); perf_unpin_context(parent_ctx); put_ctx(parent_ctx); return ret; } /* * Initialize the perf_event context in task_struct */ int perf_event_init_task(struct task_struct *child) { int ctxn, ret; memset(child->perf_event_ctxp, 0, sizeof(child->perf_event_ctxp)); mutex_init(&child->perf_event_mutex); INIT_LIST_HEAD(&child->perf_event_list); for_each_task_context_nr(ctxn) { ret = perf_event_init_context(child, ctxn); if (ret) { perf_event_free_task(child); return ret; } } return 0; } static void __init perf_event_init_all_cpus(void) { struct swevent_htable *swhash; int cpu; for_each_possible_cpu(cpu) { swhash = &per_cpu(swevent_htable, cpu); mutex_init(&swhash->hlist_mutex); INIT_LIST_HEAD(&per_cpu(rotation_list, cpu)); } } static void __cpuinit perf_event_init_cpu(int cpu) { struct swevent_htable *swhash = &per_cpu(swevent_htable, cpu); mutex_lock(&swhash->hlist_mutex); swhash->online = true; if (swhash->hlist_refcount > 0) { struct swevent_hlist *hlist; hlist = kzalloc_node(sizeof(*hlist), GFP_KERNEL, cpu_to_node(cpu)); WARN_ON(!hlist); rcu_assign_pointer(swhash->swevent_hlist, hlist); } mutex_unlock(&swhash->hlist_mutex); } #if defined CONFIG_HOTPLUG_CPU || defined CONFIG_KEXEC static void perf_pmu_rotate_stop(struct pmu *pmu) { struct perf_cpu_context *cpuctx = this_cpu_ptr(pmu->pmu_cpu_context); WARN_ON(!irqs_disabled()); list_del_init(&cpuctx->rotation_list); } static void __perf_event_exit_context(void *__info) { struct remove_event re = { .detach_group = false }; struct perf_event_context *ctx = __info; perf_pmu_rotate_stop(ctx->pmu); rcu_read_lock(); list_for_each_entry_rcu(re.event, &ctx->event_list, event_entry) __perf_remove_from_context(&re); rcu_read_unlock(); } static void perf_event_exit_cpu_context(int cpu) { struct perf_event_context *ctx; struct pmu *pmu; int idx; idx = srcu_read_lock(&pmus_srcu); list_for_each_entry_rcu(pmu, &pmus, entry) { ctx = &per_cpu_ptr(pmu->pmu_cpu_context, cpu)->ctx; mutex_lock(&ctx->mutex); smp_call_function_single(cpu, __perf_event_exit_context, ctx, 1); mutex_unlock(&ctx->mutex); } srcu_read_unlock(&pmus_srcu, idx); } static void perf_event_exit_cpu(int cpu) { struct swevent_htable *swhash = &per_cpu(swevent_htable, cpu); perf_event_exit_cpu_context(cpu); mutex_lock(&swhash->hlist_mutex); swhash->online = false; swevent_hlist_release(swhash); mutex_unlock(&swhash->hlist_mutex); } #else static inline void perf_event_exit_cpu(int cpu) { } #endif static int perf_reboot(struct notifier_block *notifier, unsigned long val, void *v) { int cpu; for_each_online_cpu(cpu) perf_event_exit_cpu(cpu); return NOTIFY_OK; } /* * Run the perf reboot notifier at the very last possible moment so that * the generic watchdog code runs as long as possible. */ static struct notifier_block perf_reboot_notifier = { .notifier_call = perf_reboot, .priority = INT_MIN, }; static int __cpuinit perf_cpu_notify(struct notifier_block *self, unsigned long action, void *hcpu) { unsigned int cpu = (long)hcpu; switch (action & ~CPU_TASKS_FROZEN) { case CPU_UP_PREPARE: case CPU_DOWN_FAILED: perf_event_init_cpu(cpu); break; case CPU_UP_CANCELED: case CPU_DOWN_PREPARE: perf_event_exit_cpu(cpu); break; default: break; } return NOTIFY_OK; } void __init perf_event_init(void) { int ret; idr_init(&pmu_idr); perf_event_init_all_cpus(); init_srcu_struct(&pmus_srcu); perf_pmu_register(&perf_swevent, "software", PERF_TYPE_SOFTWARE); perf_pmu_register(&perf_cpu_clock, NULL, -1); perf_pmu_register(&perf_task_clock, NULL, -1); perf_tp_register(); perf_cpu_notifier(perf_cpu_notify); register_reboot_notifier(&perf_reboot_notifier); ret = init_hw_breakpoint(); WARN(ret, "hw_breakpoint initialization failed with: %d", ret); /* do not patch jump label more than once per second */ jump_label_rate_limit(&perf_sched_events, HZ); /* * Build time assertion that we keep the data_head at the intended * location. IOW, validation we got the __reserved[] size right. */ BUILD_BUG_ON((offsetof(struct perf_event_mmap_page, data_head)) != 1024); } static int __init perf_event_sysfs_init(void) { struct pmu *pmu; int ret; mutex_lock(&pmus_lock); ret = bus_register(&pmu_bus); if (ret) goto unlock; list_for_each_entry(pmu, &pmus, entry) { if (!pmu->name || pmu->type < 0) continue; ret = pmu_dev_alloc(pmu); WARN(ret, "Failed to register pmu: %s, reason %d\n", pmu->name, ret); } pmu_bus_running = 1; ret = 0; unlock: mutex_unlock(&pmus_lock); return ret; } device_initcall(perf_event_sysfs_init); #ifdef CONFIG_CGROUP_PERF static struct cgroup_subsys_state *perf_cgroup_css_alloc(struct cgroup *cont) { struct perf_cgroup *jc; jc = kzalloc(sizeof(*jc), GFP_KERNEL); if (!jc) return ERR_PTR(-ENOMEM); jc->info = alloc_percpu(struct perf_cgroup_info); if (!jc->info) { kfree(jc); return ERR_PTR(-ENOMEM); } return &jc->css; } static void perf_cgroup_css_free(struct cgroup *cont) { struct perf_cgroup *jc; jc = container_of(cgroup_subsys_state(cont, perf_subsys_id), struct perf_cgroup, css); free_percpu(jc->info); kfree(jc); } static int __perf_cgroup_move(void *info) { struct task_struct *task = info; perf_cgroup_switch(task, PERF_CGROUP_SWOUT | PERF_CGROUP_SWIN); return 0; } static void perf_cgroup_attach(struct cgroup *cgrp, struct cgroup_taskset *tset) { struct task_struct *task; cgroup_taskset_for_each(task, cgrp, tset) task_function_call(task, __perf_cgroup_move, task); } static void perf_cgroup_exit(struct cgroup *cgrp, struct cgroup *old_cgrp, struct task_struct *task) { /* * cgroup_exit() is called in the copy_process() failure path. * Ignore this case since the task hasn't ran yet, this avoids * trying to poke a half freed task state from generic code. */ if (!(task->flags & PF_EXITING)) return; task_function_call(task, __perf_cgroup_move, task); } struct cgroup_subsys perf_subsys = { .name = "perf_event", .subsys_id = perf_subsys_id, .css_alloc = perf_cgroup_css_alloc, .css_free = perf_cgroup_css_free, .exit = perf_cgroup_exit, .attach = perf_cgroup_attach, }; #endif /* CONFIG_CGROUP_PERF */