/* * Performance events core code: * * Copyright (C) 2008 Thomas Gleixner * Copyright (C) 2008-2009 Red Hat, Inc., Ingo Molnar * Copyright (C) 2008-2009 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 /* * Each CPU has a list of per CPU events: */ static DEFINE_PER_CPU(struct perf_cpu_context, perf_cpu_context); int perf_max_events __read_mostly = 1; static int perf_reserved_percpu __read_mostly; static int perf_overcommit __read_mostly = 1; static atomic_t nr_events __read_mostly; static atomic_t nr_mmap_events __read_mostly; static atomic_t nr_comm_events __read_mostly; static atomic_t nr_task_events __read_mostly; /* * 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; int sysctl_perf_event_mlock __read_mostly = 512; /* 'free' kb per user */ /* * max perf event sample rate */ int sysctl_perf_event_sample_rate __read_mostly = 100000; static atomic64_t perf_event_id; /* * Lock for (sysadmin-configurable) event reservations: */ static DEFINE_SPINLOCK(perf_resource_lock); /* * Architecture provided APIs - weak aliases: */ extern __weak const struct pmu *hw_perf_event_init(struct perf_event *event) { return NULL; } void __weak hw_perf_disable(void) { barrier(); } void __weak hw_perf_enable(void) { barrier(); } void __weak perf_event_print_debug(void) { } static DEFINE_PER_CPU(int, perf_disable_count); void perf_disable(void) { if (!__get_cpu_var(perf_disable_count)++) hw_perf_disable(); } void perf_enable(void) { if (!--__get_cpu_var(perf_disable_count)) hw_perf_enable(); } static void get_ctx(struct perf_event_context *ctx) { WARN_ON(!atomic_inc_not_zero(&ctx->refcount)); } static void free_ctx(struct rcu_head *head) { struct perf_event_context *ctx; ctx = container_of(head, struct perf_event_context, rcu_head); kfree(ctx); } 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); call_rcu(&ctx->rcu_head, free_ctx); } } static void unclone_ctx(struct perf_event_context *ctx) { if (ctx->parent_ctx) { put_ctx(ctx->parent_ctx); ctx->parent_ctx = NULL; } } /* * 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, unsigned long *flags) { struct perf_event_context *ctx; rcu_read_lock(); retry: ctx = rcu_dereference(task->perf_event_ctxp); 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)) { raw_spin_unlock_irqrestore(&ctx->lock, *flags); goto retry; } if (!atomic_inc_not_zero(&ctx->refcount)) { raw_spin_unlock_irqrestore(&ctx->lock, *flags); ctx = NULL; } } rcu_read_unlock(); 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) { struct perf_event_context *ctx; unsigned long flags; ctx = perf_lock_task_context(task, &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); put_ctx(ctx); } static inline u64 perf_clock(void) { return cpu_clock(raw_smp_processor_id()); } /* * 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; } /* * Update the total_time_enabled and total_time_running fields for a event. */ 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; 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 = ctx->time; 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); } list_add_rcu(&event->event_entry, &ctx->event_list); ctx->nr_events++; if (event->attr.inherit_stat) ctx->nr_stat++; } static void perf_group_attach(struct perf_event *event) { struct perf_event *group_leader = event->group_leader; WARN_ON_ONCE(event->attach_state & PERF_ATTACH_GROUP); 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++; } /* * 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) { /* * 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; 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--; return; } 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; } } static void event_sched_out(struct perf_event *event, struct perf_cpu_context *cpuctx, struct perf_event_context *ctx) { 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 = ctx->time; event->pmu->disable(event); event->oncpu = -1; if (!is_software_event(event)) cpuctx->active_oncpu--; ctx->nr_active--; 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; if (group_event->state != PERF_EVENT_STATE_ACTIVE) return; 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 (group_event->attr.exclusive) cpuctx->exclusive = 0; } /* * 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 void __perf_event_remove_from_context(void *info) { struct perf_cpu_context *cpuctx = &__get_cpu_var(perf_cpu_context); struct perf_event *event = info; struct perf_event_context *ctx = event->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. */ if (ctx->task && cpuctx->task_ctx != ctx) return; raw_spin_lock(&ctx->lock); /* * Protect the list operation against NMI by disabling the * events on a global level. */ perf_disable(); event_sched_out(event, cpuctx, ctx); list_del_event(event, ctx); if (!ctx->task) { /* * Allow more per task events with respect to the * reservation: */ cpuctx->max_pertask = min(perf_max_events - ctx->nr_events, perf_max_events - perf_reserved_percpu); } perf_enable(); raw_spin_unlock(&ctx->lock); } /* * Remove the event from a task's (or a CPU's) list of events. * * Must be called with ctx->mutex held. * * 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_event_remove_from_context(struct perf_event *event) { struct perf_event_context *ctx = event->ctx; struct task_struct *task = ctx->task; if (!task) { /* * Per cpu events are removed via an smp call and * the removal is always successful. */ smp_call_function_single(event->cpu, __perf_event_remove_from_context, event, 1); return; } retry: task_oncpu_function_call(task, __perf_event_remove_from_context, event); raw_spin_lock_irq(&ctx->lock); /* * If the context is active we need to retry the smp call. */ if (ctx->nr_active && !list_empty(&event->group_entry)) { raw_spin_unlock_irq(&ctx->lock); goto retry; } /* * The lock prevents that this context is scheduled in so we * can remove the event safely, if the call above did not * succeed. */ if (!list_empty(&event->group_entry)) list_del_event(event, ctx); raw_spin_unlock_irq(&ctx->lock); } /* * Cross CPU call to disable a performance event */ static void __perf_event_disable(void *info) { struct perf_event *event = info; struct perf_cpu_context *cpuctx = &__get_cpu_var(perf_cpu_context); struct perf_event_context *ctx = event->ctx; /* * If this is a per-task event, need to check whether this * event's task is the current task on this cpu. */ if (ctx->task && cpuctx->task_ctx != ctx) return; 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_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); } /* * 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 */ smp_call_function_single(event->cpu, __perf_event_disable, event, 1); return; } retry: task_oncpu_function_call(task, __perf_event_disable, event); 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); 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); } static int event_sched_in(struct perf_event *event, struct perf_cpu_context *cpuctx, struct perf_event_context *ctx) { if (event->state <= PERF_EVENT_STATE_OFF) return 0; event->state = PERF_EVENT_STATE_ACTIVE; event->oncpu = smp_processor_id(); /* * The new state must be visible before we turn it on in the hardware: */ smp_wmb(); if (event->pmu->enable(event)) { event->state = PERF_EVENT_STATE_INACTIVE; event->oncpu = -1; return -EAGAIN; } event->tstamp_running += ctx->time - event->tstamp_stopped; if (!is_software_event(event)) cpuctx->active_oncpu++; ctx->nr_active++; 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; const struct pmu *pmu = group_event->pmu; bool txn = false; int ret; if (group_event->state == PERF_EVENT_STATE_OFF) return 0; /* Check if group transaction availabe */ if (pmu->start_txn) txn = true; if (txn) pmu->start_txn(pmu); if (event_sched_in(group_event, cpuctx, ctx)) { if (txn) 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 (!txn) return 0; ret = pmu->commit_txn(pmu); if (!ret) { pmu->cancel_txn(pmu); return 0; } group_error: /* * Groups can be scheduled in as one unit only, so undo any * partial group before returning: */ list_for_each_entry(event, &group_event->sibling_list, group_entry) { if (event == partial_group) break; event_sched_out(event, cpuctx, ctx); } event_sched_out(group_event, cpuctx, ctx); if (txn) 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) { list_add_event(event, ctx); perf_group_attach(event); event->tstamp_enabled = ctx->time; event->tstamp_running = ctx->time; event->tstamp_stopped = ctx->time; } /* * Cross CPU call to install and enable a performance event * * Must be called with ctx->mutex held */ static void __perf_install_in_context(void *info) { struct perf_cpu_context *cpuctx = &__get_cpu_var(perf_cpu_context); struct perf_event *event = info; struct perf_event_context *ctx = event->ctx; struct perf_event *leader = event->group_leader; int err; /* * 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. * Or possibly this is the right context but it isn't * on this cpu because it had no events. */ if (ctx->task && cpuctx->task_ctx != ctx) { if (cpuctx->task_ctx || ctx->task != current) return; cpuctx->task_ctx = ctx; } raw_spin_lock(&ctx->lock); ctx->is_active = 1; update_context_time(ctx); /* * Protect the list operation against NMI by disabling the * events on a global level. NOP for non NMI based events. */ perf_disable(); add_event_to_ctx(event, ctx); if (event->cpu != -1 && event->cpu != smp_processor_id()) goto unlock; /* * Don't put the event on if it is disabled or if * it is in a group and the group isn't on. */ if (event->state != PERF_EVENT_STATE_INACTIVE || (leader != event && leader->state != PERF_EVENT_STATE_ACTIVE)) goto unlock; /* * An exclusive event can't go on if there are already active * hardware events, and no hardware event can go on if there * is already an exclusive event on. */ if (!group_can_go_on(event, cpuctx, 1)) err = -EEXIST; else err = event_sched_in(event, cpuctx, ctx); if (err) { /* * This event couldn't go on. If it is in a group * then we have to pull the whole group off. * If the event group is pinned then put it in error state. */ if (leader != event) group_sched_out(leader, cpuctx, ctx); if (leader->attr.pinned) { update_group_times(leader); leader->state = PERF_EVENT_STATE_ERROR; } } if (!err && !ctx->task && cpuctx->max_pertask) cpuctx->max_pertask--; unlock: perf_enable(); raw_spin_unlock(&ctx->lock); } /* * 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. * * Must be called with ctx->mutex held. */ static void perf_install_in_context(struct perf_event_context *ctx, struct perf_event *event, int cpu) { struct task_struct *task = ctx->task; if (!task) { /* * Per cpu events are installed via an smp call and * the install is always successful. */ smp_call_function_single(cpu, __perf_install_in_context, event, 1); return; } retry: task_oncpu_function_call(task, __perf_install_in_context, event); raw_spin_lock_irq(&ctx->lock); /* * we need to retry the smp call. */ if (ctx->is_active && list_empty(&event->group_entry)) { raw_spin_unlock_irq(&ctx->lock); goto retry; } /* * The lock prevents that this context is scheduled in so we * can add the event safely, if it the call above did not * succeed. */ if (list_empty(&event->group_entry)) 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_context *ctx) { struct perf_event *sub; event->state = PERF_EVENT_STATE_INACTIVE; event->tstamp_enabled = ctx->time - event->total_time_enabled; list_for_each_entry(sub, &event->sibling_list, group_entry) if (sub->state >= PERF_EVENT_STATE_INACTIVE) sub->tstamp_enabled = ctx->time - sub->total_time_enabled; } /* * Cross CPU call to enable a performance event */ static void __perf_event_enable(void *info) { struct perf_event *event = info; struct perf_cpu_context *cpuctx = &__get_cpu_var(perf_cpu_context); struct perf_event_context *ctx = event->ctx; struct perf_event *leader = event->group_leader; int err; /* * If this is a per-task event, need to check whether this * event's task is the current task on this cpu. */ if (ctx->task && cpuctx->task_ctx != ctx) { if (cpuctx->task_ctx || ctx->task != current) return; cpuctx->task_ctx = ctx; } raw_spin_lock(&ctx->lock); ctx->is_active = 1; update_context_time(ctx); if (event->state >= PERF_EVENT_STATE_INACTIVE) goto unlock; __perf_event_mark_enabled(event, ctx); if (event->cpu != -1 && event->cpu != smp_processor_id()) 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 { perf_disable(); if (event == leader) err = group_sched_in(event, cpuctx, ctx); else err = event_sched_in(event, cpuctx, ctx); perf_enable(); } 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); } /* * 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 */ smp_call_function_single(event->cpu, __perf_event_enable, event, 1); 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: raw_spin_unlock_irq(&ctx->lock); task_oncpu_function_call(task, __perf_event_enable, event); 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) 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_OFF) __perf_event_mark_enabled(event, ctx); out: raw_spin_unlock_irq(&ctx->lock); } static int perf_event_refresh(struct perf_event *event, int refresh) { /* * not supported on inherited events */ if (event->attr.inherit) return -EINVAL; atomic_add(refresh, &event->event_limit); perf_event_enable(event); return 0; } enum event_type_t { EVENT_FLEXIBLE = 0x1, EVENT_PINNED = 0x2, EVENT_ALL = EVENT_FLEXIBLE | EVENT_PINNED, }; 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; raw_spin_lock(&ctx->lock); ctx->is_active = 0; if (likely(!ctx->nr_events)) goto out; update_context_time(ctx); perf_disable(); if (!ctx->nr_active) goto out_enable; if (event_type & EVENT_PINNED) list_for_each_entry(event, &ctx->pinned_groups, group_entry) group_sched_out(event, cpuctx, ctx); if (event_type & EVENT_FLEXIBLE) list_for_each_entry(event, &ctx->flexible_groups, group_entry) group_sched_out(event, cpuctx, ctx); out_enable: perf_enable(); out: raw_spin_unlock(&ctx->lock); } /* * 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 = atomic64_read(&next_event->count); value = atomic64_xchg(&event->count, value); atomic64_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); } #define list_next_entry(pos, member) \ list_entry(pos->member.next, typeof(*pos), member) 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); } } /* * 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) { struct perf_cpu_context *cpuctx = &__get_cpu_var(perf_cpu_context); struct perf_event_context *ctx = task->perf_event_ctxp; struct perf_event_context *next_ctx; struct perf_event_context *parent; int do_switch = 1; perf_sw_event(PERF_COUNT_SW_CONTEXT_SWITCHES, 1, 1, NULL, 0); if (likely(!ctx || !cpuctx->task_ctx)) return; rcu_read_lock(); parent = rcu_dereference(ctx->parent_ctx); next_ctx = next->perf_event_ctxp; 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 = next_ctx; next->perf_event_ctxp = 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) { ctx_sched_out(ctx, cpuctx, EVENT_ALL); cpuctx->task_ctx = NULL; } } static void task_ctx_sched_out(struct perf_event_context *ctx, enum event_type_t event_type) { struct perf_cpu_context *cpuctx = &__get_cpu_var(perf_cpu_context); if (!cpuctx->task_ctx) return; if (WARN_ON_ONCE(ctx != cpuctx->task_ctx)) return; ctx_sched_out(ctx, cpuctx, event_type); cpuctx->task_ctx = NULL; } /* * Called with IRQs disabled */ static void __perf_event_task_sched_out(struct perf_event_context *ctx) { task_ctx_sched_out(ctx, EVENT_ALL); } /* * 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->cpu != -1 && event->cpu != smp_processor_id()) continue; 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->cpu != -1 && event->cpu != smp_processor_id()) continue; 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) { raw_spin_lock(&ctx->lock); ctx->is_active = 1; if (likely(!ctx->nr_events)) goto out; ctx->timestamp = perf_clock(); perf_disable(); /* * First go through the list and put on any pinned groups * in order to give them the best chance of going on. */ if (event_type & EVENT_PINNED) ctx_pinned_sched_in(ctx, cpuctx); /* Then walk through the lower prio flexible groups */ if (event_type & EVENT_FLEXIBLE) ctx_flexible_sched_in(ctx, cpuctx); perf_enable(); out: raw_spin_unlock(&ctx->lock); } static void cpu_ctx_sched_in(struct perf_cpu_context *cpuctx, enum event_type_t event_type) { struct perf_event_context *ctx = &cpuctx->ctx; ctx_sched_in(ctx, cpuctx, event_type); } static void task_ctx_sched_in(struct task_struct *task, enum event_type_t event_type) { struct perf_cpu_context *cpuctx = &__get_cpu_var(perf_cpu_context); struct perf_event_context *ctx = task->perf_event_ctxp; if (likely(!ctx)) return; if (cpuctx->task_ctx == ctx) return; ctx_sched_in(ctx, cpuctx, event_type); cpuctx->task_ctx = ctx; } /* * 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 *task) { struct perf_cpu_context *cpuctx = &__get_cpu_var(perf_cpu_context); struct perf_event_context *ctx = task->perf_event_ctxp; if (likely(!ctx)) return; if (cpuctx->task_ctx == ctx) return; perf_disable(); /* * 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); ctx_sched_in(ctx, cpuctx, EVENT_PINNED); cpu_ctx_sched_in(cpuctx, EVENT_FLEXIBLE); ctx_sched_in(ctx, cpuctx, EVENT_FLEXIBLE); cpuctx->task_ctx = ctx; perf_enable(); } #define MAX_INTERRUPTS (~0ULL) static void perf_log_throttle(struct perf_event *event, int enable); 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 void perf_event_stop(struct perf_event *event) { if (!event->pmu->stop) return event->pmu->disable(event); return event->pmu->stop(event); } static int perf_event_start(struct perf_event *event) { if (!event->pmu->start) return event->pmu->enable(event); return event->pmu->start(event); } static void perf_adjust_period(struct perf_event *event, u64 nsec, u64 count) { 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 (atomic64_read(&hwc->period_left) > 8*sample_period) { perf_disable(); perf_event_stop(event); atomic64_set(&hwc->period_left, 0); perf_event_start(event); perf_enable(); } } static void perf_ctx_adjust_freq(struct perf_event_context *ctx) { struct perf_event *event; struct hw_perf_event *hwc; u64 interrupts, now; s64 delta; raw_spin_lock(&ctx->lock); list_for_each_entry_rcu(event, &ctx->event_list, event_entry) { if (event->state != PERF_EVENT_STATE_ACTIVE) continue; if (event->cpu != -1 && event->cpu != smp_processor_id()) continue; hwc = &event->hw; interrupts = hwc->interrupts; hwc->interrupts = 0; /* * unthrottle events on the tick */ if (interrupts == MAX_INTERRUPTS) { perf_log_throttle(event, 1); perf_disable(); event->pmu->unthrottle(event); perf_enable(); } if (!event->attr.freq || !event->attr.sample_freq) continue; perf_disable(); event->pmu->read(event); now = atomic64_read(&event->count); delta = now - hwc->freq_count_stamp; hwc->freq_count_stamp = now; if (delta > 0) perf_adjust_period(event, TICK_NSEC, delta); perf_enable(); } raw_spin_unlock(&ctx->lock); } /* * Round-robin a context's events: */ static void rotate_ctx(struct perf_event_context *ctx) { raw_spin_lock(&ctx->lock); /* Rotate the first entry last of non-pinned groups */ list_rotate_left(&ctx->flexible_groups); raw_spin_unlock(&ctx->lock); } void perf_event_task_tick(struct task_struct *curr) { struct perf_cpu_context *cpuctx; struct perf_event_context *ctx; int rotate = 0; if (!atomic_read(&nr_events)) return; cpuctx = &__get_cpu_var(perf_cpu_context); if (cpuctx->ctx.nr_events && cpuctx->ctx.nr_events != cpuctx->ctx.nr_active) rotate = 1; ctx = curr->perf_event_ctxp; if (ctx && ctx->nr_events && ctx->nr_events != ctx->nr_active) rotate = 1; perf_ctx_adjust_freq(&cpuctx->ctx); if (ctx) perf_ctx_adjust_freq(ctx); if (!rotate) return; perf_disable(); cpu_ctx_sched_out(cpuctx, EVENT_FLEXIBLE); if (ctx) task_ctx_sched_out(ctx, EVENT_FLEXIBLE); rotate_ctx(&cpuctx->ctx); if (ctx) rotate_ctx(ctx); cpu_ctx_sched_in(cpuctx, EVENT_FLEXIBLE); if (ctx) task_ctx_sched_in(curr, EVENT_FLEXIBLE); perf_enable(); } 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, ctx); 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 task_struct *task) { struct perf_event_context *ctx; struct perf_event *event; unsigned long flags; int enabled = 0; int ret; local_irq_save(flags); ctx = task->perf_event_ctxp; if (!ctx || !ctx->nr_events) goto out; __perf_event_task_sched_out(ctx); raw_spin_lock(&ctx->lock); list_for_each_entry(event, &ctx->pinned_groups, group_entry) { ret = event_enable_on_exec(event, ctx); if (ret) enabled = 1; } list_for_each_entry(event, &ctx->flexible_groups, group_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); perf_event_task_sched_in(task); out: local_irq_restore(flags); } /* * Cross CPU call to read the hardware event */ static void __perf_event_read(void *info) { struct perf_cpu_context *cpuctx = &__get_cpu_var(perf_cpu_context); struct perf_event *event = info; struct perf_event_context *ctx = event->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); update_context_time(ctx); update_event_times(event); raw_spin_unlock(&ctx->lock); event->pmu->read(event); } 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); update_context_time(ctx); update_event_times(event); raw_spin_unlock_irqrestore(&ctx->lock, flags); } return atomic64_read(&event->count); } /* * Initialize the perf_event context in a task_struct: */ static void __perf_event_init_context(struct perf_event_context *ctx, struct task_struct *task) { 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); ctx->task = task; } static struct perf_event_context *find_get_context(pid_t pid, int cpu) { struct perf_event_context *ctx; struct perf_cpu_context *cpuctx; struct task_struct *task; unsigned long flags; int err; if (pid == -1 && cpu != -1) { /* Must be root to operate on a CPU event: */ if (perf_paranoid_cpu() && !capable(CAP_SYS_ADMIN)) return ERR_PTR(-EACCES); if (cpu < 0 || cpu >= nr_cpumask_bits) return ERR_PTR(-EINVAL); /* * 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(perf_cpu_context, cpu); ctx = &cpuctx->ctx; get_ctx(ctx); return ctx; } rcu_read_lock(); if (!pid) task = current; else task = find_task_by_vpid(pid); if (task) get_task_struct(task); rcu_read_unlock(); if (!task) return ERR_PTR(-ESRCH); /* * Can't attach events to a dying task. */ err = -ESRCH; if (task->flags & PF_EXITING) goto errout; /* Reuse ptrace permission checks for now. */ err = -EACCES; if (!ptrace_may_access(task, PTRACE_MODE_READ)) goto errout; retry: ctx = perf_lock_task_context(task, &flags); if (ctx) { unclone_ctx(ctx); raw_spin_unlock_irqrestore(&ctx->lock, flags); } if (!ctx) { ctx = kzalloc(sizeof(struct perf_event_context), GFP_KERNEL); err = -ENOMEM; if (!ctx) goto errout; __perf_event_init_context(ctx, task); get_ctx(ctx); if (cmpxchg(&task->perf_event_ctxp, NULL, ctx)) { /* * We raced with some other task; use * the context they set. */ kfree(ctx); goto retry; } get_task_struct(task); } put_task_struct(task); return ctx; errout: put_task_struct(task); 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 perf_pending_sync(struct perf_event *event); static void perf_mmap_data_put(struct perf_mmap_data *data); static void free_event(struct perf_event *event) { perf_pending_sync(event); if (!event->parent) { atomic_dec(&nr_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->data) { perf_mmap_data_put(event->data); event->data = NULL; } if (event->destroy) event->destroy(event); 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; /* * Remove from the PMU, can't get re-enabled since we got * here because the last ref went. */ perf_event_disable(event); 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); raw_spin_lock_irq(&ctx->lock); perf_group_detach(event); list_del_event(event, ctx); raw_spin_unlock_irq(&ctx->lock); mutex_unlock(&ctx->mutex); mutex_lock(&event->owner->perf_event_mutex); list_del_init(&event->owner_entry); mutex_unlock(&event->owner->perf_event_mutex); put_task_struct(event->owner); free_event(event); return 0; } EXPORT_SYMBOL_GPL(perf_event_release_kernel); /* * Called when the last reference to the file is gone. */ static int perf_release(struct inode *inode, struct file *file) { struct perf_event *event = file->private_data; file->private_data = NULL; return perf_event_release_kernel(event); } static int 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; return size; } 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 < perf_event_read_size(event)) 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 perf_mmap_data *data; unsigned int events = POLL_HUP; rcu_read_lock(); data = rcu_dereference(event->data); if (data) events = atomic_xchg(&data->poll, 0); rcu_read_unlock(); poll_wait(file, &event->waitq, wait); return events; } static void perf_event_reset(struct perf_event *event) { (void)perf_event_read(event); atomic64_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); func(event); list_for_each_entry(sibling, &event->sibling_list, group_entry) perf_event_for_each_child(event, func); mutex_unlock(&ctx->mutex); } static int perf_event_period(struct perf_event *event, u64 __user *arg) { struct perf_event_context *ctx = event->ctx; unsigned long size; int ret = 0; u64 value; if (!event->attr.sample_period) return -EINVAL; size = copy_from_user(&value, arg, sizeof(value)); if (size != 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 struct perf_event *perf_fget_light(int fd, int *fput_needed) { struct file *file; file = fget_light(fd, fput_needed); if (!file) return ERR_PTR(-EBADF); if (file->f_op != &perf_fops) { fput_light(file, *fput_needed); *fput_needed = 0; return ERR_PTR(-EBADF); } return file->private_data; } 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: { struct perf_event *output_event = NULL; int fput_needed = 0; int ret; if (arg != -1) { output_event = perf_fget_light(arg, &fput_needed); if (IS_ERR(output_event)) return PTR_ERR(output_event); } ret = perf_event_set_output(event, output_event); if (output_event) fput_light(output_event->filp, fput_needed); 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; } 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; } #ifndef PERF_EVENT_INDEX_OFFSET # define PERF_EVENT_INDEX_OFFSET 0 #endif static int perf_event_index(struct perf_event *event) { if (event->state != PERF_EVENT_STATE_ACTIVE) return 0; return event->hw.idx + 1 - PERF_EVENT_INDEX_OFFSET; } /* * 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 perf_mmap_data *data; rcu_read_lock(); data = rcu_dereference(event->data); if (!data) goto unlock; userpg = data->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 = atomic64_read(&event->count); if (event->state == PERF_EVENT_STATE_ACTIVE) userpg->offset -= atomic64_read(&event->hw.prev_count); userpg->time_enabled = event->total_time_enabled + atomic64_read(&event->child_total_time_enabled); userpg->time_running = event->total_time_running + atomic64_read(&event->child_total_time_running); barrier(); ++userpg->lock; preempt_enable(); unlock: rcu_read_unlock(); } #ifndef CONFIG_PERF_USE_VMALLOC /* * Back perf_mmap() with regular GFP_KERNEL-0 pages. */ static struct page * perf_mmap_to_page(struct perf_mmap_data *data, unsigned long pgoff) { if (pgoff > data->nr_pages) return NULL; if (pgoff == 0) return virt_to_page(data->user_page); return virt_to_page(data->data_pages[pgoff - 1]); } static void *perf_mmap_alloc_page(int cpu) { struct page *page; int node; node = (cpu == -1) ? cpu : cpu_to_node(cpu); page = alloc_pages_node(node, GFP_KERNEL | __GFP_ZERO, 0); if (!page) return NULL; return page_address(page); } static struct perf_mmap_data * perf_mmap_data_alloc(struct perf_event *event, int nr_pages) { struct perf_mmap_data *data; unsigned long size; int i; size = sizeof(struct perf_mmap_data); size += nr_pages * sizeof(void *); data = kzalloc(size, GFP_KERNEL); if (!data) goto fail; data->user_page = perf_mmap_alloc_page(event->cpu); if (!data->user_page) goto fail_user_page; for (i = 0; i < nr_pages; i++) { data->data_pages[i] = perf_mmap_alloc_page(event->cpu); if (!data->data_pages[i]) goto fail_data_pages; } data->nr_pages = nr_pages; return data; fail_data_pages: for (i--; i >= 0; i--) free_page((unsigned long)data->data_pages[i]); free_page((unsigned long)data->user_page); fail_user_page: kfree(data); fail: return NULL; } static void perf_mmap_free_page(unsigned long addr) { struct page *page = virt_to_page((void *)addr); page->mapping = NULL; __free_page(page); } static void perf_mmap_data_free(struct perf_mmap_data *data) { int i; perf_mmap_free_page((unsigned long)data->user_page); for (i = 0; i < data->nr_pages; i++) perf_mmap_free_page((unsigned long)data->data_pages[i]); kfree(data); } static inline int page_order(struct perf_mmap_data *data) { return 0; } #else /* * Back perf_mmap() with vmalloc memory. * * Required for architectures that have d-cache aliasing issues. */ static inline int page_order(struct perf_mmap_data *data) { return data->page_order; } static struct page * perf_mmap_to_page(struct perf_mmap_data *data, unsigned long pgoff) { if (pgoff > (1UL << page_order(data))) return NULL; return vmalloc_to_page((void *)data->user_page + pgoff * PAGE_SIZE); } static void perf_mmap_unmark_page(void *addr) { struct page *page = vmalloc_to_page(addr); page->mapping = NULL; } static void perf_mmap_data_free_work(struct work_struct *work) { struct perf_mmap_data *data; void *base; int i, nr; data = container_of(work, struct perf_mmap_data, work); nr = 1 << page_order(data); base = data->user_page; for (i = 0; i < nr + 1; i++) perf_mmap_unmark_page(base + (i * PAGE_SIZE)); vfree(base); kfree(data); } static void perf_mmap_data_free(struct perf_mmap_data *data) { schedule_work(&data->work); } static struct perf_mmap_data * perf_mmap_data_alloc(struct perf_event *event, int nr_pages) { struct perf_mmap_data *data; unsigned long size; void *all_buf; size = sizeof(struct perf_mmap_data); size += sizeof(void *); data = kzalloc(size, GFP_KERNEL); if (!data) goto fail; INIT_WORK(&data->work, perf_mmap_data_free_work); all_buf = vmalloc_user((nr_pages + 1) * PAGE_SIZE); if (!all_buf) goto fail_all_buf; data->user_page = all_buf; data->data_pages[0] = all_buf + PAGE_SIZE; data->page_order = ilog2(nr_pages); data->nr_pages = 1; return data; fail_all_buf: kfree(data); fail: return NULL; } #endif static unsigned long perf_data_size(struct perf_mmap_data *data) { return data->nr_pages << (PAGE_SHIFT + page_order(data)); } static int perf_mmap_fault(struct vm_area_struct *vma, struct vm_fault *vmf) { struct perf_event *event = vma->vm_file->private_data; struct perf_mmap_data *data; int ret = VM_FAULT_SIGBUS; if (vmf->flags & FAULT_FLAG_MKWRITE) { if (vmf->pgoff == 0) ret = 0; return ret; } rcu_read_lock(); data = rcu_dereference(event->data); if (!data) goto unlock; if (vmf->pgoff && (vmf->flags & FAULT_FLAG_WRITE)) goto unlock; vmf->page = perf_mmap_to_page(data, 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 perf_mmap_data_init(struct perf_event *event, struct perf_mmap_data *data) { long max_size = perf_data_size(data); if (event->attr.watermark) { data->watermark = min_t(long, max_size, event->attr.wakeup_watermark); } if (!data->watermark) data->watermark = max_size / 2; atomic_set(&data->refcount, 1); rcu_assign_pointer(event->data, data); } static void perf_mmap_data_free_rcu(struct rcu_head *rcu_head) { struct perf_mmap_data *data; data = container_of(rcu_head, struct perf_mmap_data, rcu_head); perf_mmap_data_free(data); } static struct perf_mmap_data *perf_mmap_data_get(struct perf_event *event) { struct perf_mmap_data *data; rcu_read_lock(); data = rcu_dereference(event->data); if (data) { if (!atomic_inc_not_zero(&data->refcount)) data = NULL; } rcu_read_unlock(); return data; } static void perf_mmap_data_put(struct perf_mmap_data *data) { if (!atomic_dec_and_test(&data->refcount)) return; call_rcu(&data->rcu_head, perf_mmap_data_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); } static void perf_mmap_close(struct vm_area_struct *vma) { struct perf_event *event = vma->vm_file->private_data; if (atomic_dec_and_mutex_lock(&event->mmap_count, &event->mmap_mutex)) { unsigned long size = perf_data_size(event->data); struct user_struct *user = event->mmap_user; struct perf_mmap_data *data = event->data; atomic_long_sub((size >> PAGE_SHIFT) + 1, &user->locked_vm); vma->vm_mm->locked_vm -= event->mmap_locked; rcu_assign_pointer(event->data, NULL); mutex_unlock(&event->mmap_mutex); perf_mmap_data_put(data); free_uid(user); } } 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 perf_mmap_data *data; unsigned long vma_size; unsigned long nr_pages; long user_extra, extra; int ret = 0; /* * Don't allow mmap() of inherited per-task counters. This would * create a performance issue due to all children writing to the * same buffer. */ 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 data 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); mutex_lock(&event->mmap_mutex); if (event->data) { if (event->data->nr_pages == nr_pages) atomic_inc(&event->data->refcount); else ret = -EINVAL; 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->locked_vm + extra; if ((locked > lock_limit) && perf_paranoid_tracepoint_raw() && !capable(CAP_IPC_LOCK)) { ret = -EPERM; goto unlock; } WARN_ON(event->data); data = perf_mmap_data_alloc(event, nr_pages); if (!data) { ret = -ENOMEM; goto unlock; } perf_mmap_data_init(event, data); if (vma->vm_flags & VM_WRITE) event->data->writable = 1; atomic_long_add(user_extra, &user->locked_vm); event->mmap_locked = extra; event->mmap_user = get_current_user(); vma->vm_mm->locked_vm += event->mmap_locked; unlock: if (!ret) atomic_inc(&event->mmap_count); mutex_unlock(&event->mmap_mutex); vma->vm_flags |= VM_RESERVED; vma->vm_ops = &perf_mmap_vmops; return ret; } static int perf_fasync(int fd, struct file *filp, int on) { struct inode *inode = filp->f_path.dentry->d_inode; 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_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) { wake_up_all(&event->waitq); if (event->pending_kill) { kill_fasync(&event->fasync, SIGIO, event->pending_kill); event->pending_kill = 0; } } /* * Pending wakeups * * Handle the case where we need to wakeup up from NMI (or rq->lock) context. * * The NMI bit means we cannot possibly take locks. Therefore, maintain a * single linked list and use cmpxchg() to add entries lockless. */ static void perf_pending_event(struct perf_pending_entry *entry) { struct perf_event *event = container_of(entry, struct perf_event, pending); if (event->pending_disable) { event->pending_disable = 0; __perf_event_disable(event); } if (event->pending_wakeup) { event->pending_wakeup = 0; perf_event_wakeup(event); } } #define PENDING_TAIL ((struct perf_pending_entry *)-1UL) static DEFINE_PER_CPU(struct perf_pending_entry *, perf_pending_head) = { PENDING_TAIL, }; static void perf_pending_queue(struct perf_pending_entry *entry, void (*func)(struct perf_pending_entry *)) { struct perf_pending_entry **head; if (cmpxchg(&entry->next, NULL, PENDING_TAIL) != NULL) return; entry->func = func; head = &get_cpu_var(perf_pending_head); do { entry->next = *head; } while (cmpxchg(head, entry->next, entry) != entry->next); set_perf_event_pending(); put_cpu_var(perf_pending_head); } static int __perf_pending_run(void) { struct perf_pending_entry *list; int nr = 0; list = xchg(&__get_cpu_var(perf_pending_head), PENDING_TAIL); while (list != PENDING_TAIL) { void (*func)(struct perf_pending_entry *); struct perf_pending_entry *entry = list; list = list->next; func = entry->func; entry->next = NULL; /* * Ensure we observe the unqueue before we issue the wakeup, * so that we won't be waiting forever. * -- see perf_not_pending(). */ smp_wmb(); func(entry); nr++; } return nr; } static inline int perf_not_pending(struct perf_event *event) { /* * If we flush on whatever cpu we run, there is a chance we don't * need to wait. */ get_cpu(); __perf_pending_run(); put_cpu(); /* * Ensure we see the proper queue state before going to sleep * so that we do not miss the wakeup. -- see perf_pending_handle() */ smp_rmb(); return event->pending.next == NULL; } static void perf_pending_sync(struct perf_event *event) { wait_event(event->waitq, perf_not_pending(event)); } void perf_event_do_pending(void) { __perf_pending_run(); } /* * Callchain support -- arch specific */ __weak struct perf_callchain_entry *perf_callchain(struct pt_regs *regs) { return NULL; } __weak void perf_arch_fetch_caller_regs(struct pt_regs *regs, unsigned long ip, int skip) { } /* * 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); /* * Output */ static bool perf_output_space(struct perf_mmap_data *data, unsigned long tail, unsigned long offset, unsigned long head) { unsigned long mask; if (!data->writable) return true; mask = perf_data_size(data) - 1; offset = (offset - tail) & mask; head = (head - tail) & mask; if ((int)(head - offset) < 0) return false; return true; } static void perf_output_wakeup(struct perf_output_handle *handle) { atomic_set(&handle->data->poll, POLL_IN); if (handle->nmi) { handle->event->pending_wakeup = 1; perf_pending_queue(&handle->event->pending, perf_pending_event); } else perf_event_wakeup(handle->event); } /* * We need to ensure a later event_id doesn't publish a head when a former * event isn't done writing. However since we need to deal with NMIs we * cannot fully serialize things. * * We only publish the head (and generate a wakeup) when the outer-most * event completes. */ static void perf_output_get_handle(struct perf_output_handle *handle) { struct perf_mmap_data *data = handle->data; preempt_disable(); local_inc(&data->nest); handle->wakeup = local_read(&data->wakeup); } static void perf_output_put_handle(struct perf_output_handle *handle) { struct perf_mmap_data *data = handle->data; unsigned long head; again: head = local_read(&data->head); /* * IRQ/NMI can happen here, which means we can miss a head update. */ if (!local_dec_and_test(&data->nest)) goto out; /* * Publish the known good head. Rely on the full barrier implied * by atomic_dec_and_test() order the data->head read and this * write. */ data->user_page->data_head = head; /* * Now check if we missed an update, rely on the (compiler) * barrier in atomic_dec_and_test() to re-read data->head. */ if (unlikely(head != local_read(&data->head))) { local_inc(&data->nest); goto again; } if (handle->wakeup != local_read(&data->wakeup)) perf_output_wakeup(handle); out: preempt_enable(); } __always_inline void perf_output_copy(struct perf_output_handle *handle, const void *buf, unsigned int len) { do { unsigned long size = min_t(unsigned long, handle->size, len); memcpy(handle->addr, buf, size); len -= size; handle->addr += size; buf += size; handle->size -= size; if (!handle->size) { struct perf_mmap_data *data = handle->data; handle->page++; handle->page &= data->nr_pages - 1; handle->addr = data->data_pages[handle->page]; handle->size = PAGE_SIZE << page_order(data); } } while (len); } int perf_output_begin(struct perf_output_handle *handle, struct perf_event *event, unsigned int size, int nmi, int sample) { struct perf_mmap_data *data; unsigned long tail, offset, head; int have_lost; struct { struct perf_event_header header; u64 id; u64 lost; } lost_event; rcu_read_lock(); /* * For inherited events we send all the output towards the parent. */ if (event->parent) event = event->parent; data = rcu_dereference(event->data); if (!data) goto out; handle->data = data; handle->event = event; handle->nmi = nmi; handle->sample = sample; if (!data->nr_pages) goto out; have_lost = local_read(&data->lost); if (have_lost) size += sizeof(lost_event); perf_output_get_handle(handle); do { /* * Userspace could choose to issue a mb() before updating the * tail pointer. So that all reads will be completed before the * write is issued. */ tail = ACCESS_ONCE(data->user_page->data_tail); smp_rmb(); offset = head = local_read(&data->head); head += size; if (unlikely(!perf_output_space(data, tail, offset, head))) goto fail; } while (local_cmpxchg(&data->head, offset, head) != offset); if (head - local_read(&data->wakeup) > data->watermark) local_add(data->watermark, &data->wakeup); handle->page = offset >> (PAGE_SHIFT + page_order(data)); handle->page &= data->nr_pages - 1; handle->size = offset & ((PAGE_SIZE << page_order(data)) - 1); handle->addr = data->data_pages[handle->page]; handle->addr += handle->size; handle->size = (PAGE_SIZE << page_order(data)) - handle->size; if (have_lost) { lost_event.header.type = PERF_RECORD_LOST; lost_event.header.misc = 0; lost_event.header.size = sizeof(lost_event); lost_event.id = event->id; lost_event.lost = local_xchg(&data->lost, 0); perf_output_put(handle, lost_event); } return 0; fail: local_inc(&data->lost); perf_output_put_handle(handle); out: rcu_read_unlock(); return -ENOSPC; } void perf_output_end(struct perf_output_handle *handle) { struct perf_event *event = handle->event; struct perf_mmap_data *data = handle->data; int wakeup_events = event->attr.wakeup_events; if (handle->sample && wakeup_events) { int events = local_inc_return(&data->events); if (events >= wakeup_events) { local_sub(wakeup_events, &data->events); local_inc(&data->wakeup); } } perf_output_put_handle(handle); rcu_read_unlock(); } 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); } static void perf_output_read_one(struct perf_output_handle *handle, struct perf_event *event) { u64 read_format = event->attr.read_format; u64 values[4]; int n = 0; values[n++] = atomic64_read(&event->count); if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED) { values[n++] = event->total_time_enabled + atomic64_read(&event->child_total_time_enabled); } if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING) { values[n++] = event->total_time_running + atomic64_read(&event->child_total_time_running); } if (read_format & PERF_FORMAT_ID) values[n++] = primary_event_id(event); perf_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) { 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++] = leader->total_time_enabled; if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING) values[n++] = leader->total_time_running; if (leader != event) leader->pmu->read(leader); values[n++] = atomic64_read(&leader->count); if (read_format & PERF_FORMAT_ID) values[n++] = primary_event_id(leader); perf_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++] = atomic64_read(&sub->count); if (read_format & PERF_FORMAT_ID) values[n++] = primary_event_id(sub); perf_output_copy(handle, values, n * sizeof(u64)); } } static void perf_output_read(struct perf_output_handle *handle, struct perf_event *event) { if (event->attr.read_format & PERF_FORMAT_GROUP) perf_output_read_group(handle, event); else perf_output_read_one(handle, event); } 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); perf_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); perf_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); } } } 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; data->type = sample_type; header->type = PERF_RECORD_SAMPLE; header->size = sizeof(*header); header->misc = 0; header->misc |= perf_misc_flags(regs); if (sample_type & PERF_SAMPLE_IP) { data->ip = perf_instruction_pointer(regs); header->size += sizeof(data->ip); } 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); header->size += sizeof(data->tid_entry); } if (sample_type & PERF_SAMPLE_TIME) { data->time = perf_clock(); header->size += sizeof(data->time); } if (sample_type & PERF_SAMPLE_ADDR) header->size += sizeof(data->addr); if (sample_type & PERF_SAMPLE_ID) { data->id = primary_event_id(event); header->size += sizeof(data->id); } if (sample_type & PERF_SAMPLE_STREAM_ID) { data->stream_id = event->id; header->size += sizeof(data->stream_id); } if (sample_type & PERF_SAMPLE_CPU) { data->cpu_entry.cpu = raw_smp_processor_id(); data->cpu_entry.reserved = 0; header->size += sizeof(data->cpu_entry); } if (sample_type & PERF_SAMPLE_PERIOD) header->size += sizeof(data->period); if (sample_type & PERF_SAMPLE_READ) header->size += perf_event_read_size(event); if (sample_type & PERF_SAMPLE_CALLCHAIN) { int size = 1; data->callchain = perf_callchain(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; } } static void perf_event_output(struct perf_event *event, int nmi, struct perf_sample_data *data, struct pt_regs *regs) { struct perf_output_handle handle; struct perf_event_header header; perf_prepare_sample(&header, data, event, regs); if (perf_output_begin(&handle, event, header.size, nmi, 1)) return; perf_output_sample(&handle, &header, data, event); perf_output_end(&handle); } /* * 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_read_event read_event = { .header = { .type = PERF_RECORD_READ, .misc = 0, .size = sizeof(read_event) + perf_event_read_size(event), }, .pid = perf_event_pid(event, task), .tid = perf_event_tid(event, task), }; int ret; ret = perf_output_begin(&handle, event, read_event.header.size, 0, 0); if (ret) return; perf_output_put(&handle, read_event); perf_output_read(&handle, event); perf_output_end(&handle); } /* * 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, struct perf_task_event *task_event) { struct perf_output_handle handle; struct task_struct *task = task_event->task; int size, ret; size = task_event->event_id.header.size; ret = perf_output_begin(&handle, event, size, 0, 0); if (ret) return; 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_output_end(&handle); } static int perf_event_task_match(struct perf_event *event) { if (event->state < PERF_EVENT_STATE_INACTIVE) return 0; if (event->cpu != -1 && event->cpu != smp_processor_id()) return 0; if (event->attr.comm || event->attr.mmap || event->attr.mmap_data || event->attr.task) return 1; return 0; } static void perf_event_task_ctx(struct perf_event_context *ctx, struct perf_task_event *task_event) { struct perf_event *event; list_for_each_entry_rcu(event, &ctx->event_list, event_entry) { if (perf_event_task_match(event)) perf_event_task_output(event, task_event); } } static void perf_event_task_event(struct perf_task_event *task_event) { struct perf_cpu_context *cpuctx; struct perf_event_context *ctx = task_event->task_ctx; rcu_read_lock(); cpuctx = &get_cpu_var(perf_cpu_context); perf_event_task_ctx(&cpuctx->ctx, task_event); if (!ctx) ctx = rcu_dereference(current->perf_event_ctxp); if (ctx) perf_event_task_ctx(ctx, task_event); put_cpu_var(perf_cpu_context); rcu_read_unlock(); } 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_task_event(&task_event); } 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, struct perf_comm_event *comm_event) { struct perf_output_handle handle; int size = comm_event->event_id.header.size; int ret = perf_output_begin(&handle, event, size, 0, 0); if (ret) return; 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); perf_output_copy(&handle, comm_event->comm, comm_event->comm_size); perf_output_end(&handle); } static int perf_event_comm_match(struct perf_event *event) { if (event->state < PERF_EVENT_STATE_INACTIVE) return 0; if (event->cpu != -1 && event->cpu != smp_processor_id()) return 0; if (event->attr.comm) return 1; return 0; } static void perf_event_comm_ctx(struct perf_event_context *ctx, struct perf_comm_event *comm_event) { struct perf_event *event; list_for_each_entry_rcu(event, &ctx->event_list, event_entry) { if (perf_event_comm_match(event)) perf_event_comm_output(event, comm_event); } } static void perf_event_comm_event(struct perf_comm_event *comm_event) { struct perf_cpu_context *cpuctx; struct perf_event_context *ctx; unsigned int size; char comm[TASK_COMM_LEN]; 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; rcu_read_lock(); cpuctx = &get_cpu_var(perf_cpu_context); perf_event_comm_ctx(&cpuctx->ctx, comm_event); ctx = rcu_dereference(current->perf_event_ctxp); if (ctx) perf_event_comm_ctx(ctx, comm_event); put_cpu_var(perf_cpu_context); rcu_read_unlock(); } void perf_event_comm(struct task_struct *task) { struct perf_comm_event comm_event; if (task->perf_event_ctxp) perf_event_enable_on_exec(task); 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, struct perf_mmap_event *mmap_event) { struct perf_output_handle handle; int size = mmap_event->event_id.header.size; int ret = perf_output_begin(&handle, event, size, 0, 0); if (ret) return; 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); perf_output_copy(&handle, mmap_event->file_name, mmap_event->file_size); perf_output_end(&handle); } static int perf_event_mmap_match(struct perf_event *event, struct perf_mmap_event *mmap_event, int executable) { if (event->state < PERF_EVENT_STATE_INACTIVE) return 0; if (event->cpu != -1 && event->cpu != smp_processor_id()) return 0; if ((!executable && event->attr.mmap_data) || (executable && event->attr.mmap)) return 1; return 0; } static void perf_event_mmap_ctx(struct perf_event_context *ctx, struct perf_mmap_event *mmap_event, int executable) { struct perf_event *event; list_for_each_entry_rcu(event, &ctx->event_list, event_entry) { if (perf_event_mmap_match(event, mmap_event, executable)) perf_event_mmap_output(event, mmap_event); } } static void perf_event_mmap_event(struct perf_mmap_event *mmap_event) { struct perf_cpu_context *cpuctx; struct perf_event_context *ctx; 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 buffer 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)); 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; mmap_event->event_id.header.size = sizeof(mmap_event->event_id) + size; rcu_read_lock(); cpuctx = &get_cpu_var(perf_cpu_context); perf_event_mmap_ctx(&cpuctx->ctx, mmap_event, vma->vm_flags & VM_EXEC); ctx = rcu_dereference(current->perf_event_ctxp); if (ctx) perf_event_mmap_ctx(ctx, mmap_event, vma->vm_flags & VM_EXEC); put_cpu_var(perf_cpu_context); rcu_read_unlock(); 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; 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; ret = perf_output_begin(&handle, event, sizeof(throttle_event), 1, 0); if (ret) return; perf_output_put(&handle, throttle_event); perf_output_end(&handle); } /* * Generic event overflow handling, sampling. */ static int __perf_event_overflow(struct perf_event *event, int nmi, 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; int ret = 0; throttle = (throttle && event->pmu->unthrottle != NULL); if (!throttle) { hwc->interrupts++; } else { if (hwc->interrupts != MAX_INTERRUPTS) { hwc->interrupts++; if (HZ * hwc->interrupts > (u64)sysctl_perf_event_sample_rate) { hwc->interrupts = MAX_INTERRUPTS; perf_log_throttle(event, 0); ret = 1; } } else { /* * Keep re-disabling events even though on the previous * pass we disabled it - just in case we raced with a * sched-in and the event got enabled again: */ 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); } /* * 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; if (nmi) { event->pending_disable = 1; perf_pending_queue(&event->pending, perf_pending_event); } else perf_event_disable(event); } if (event->overflow_handler) event->overflow_handler(event, nmi, data, regs); else perf_event_output(event, nmi, data, regs); return ret; } int perf_event_overflow(struct perf_event *event, int nmi, struct perf_sample_data *data, struct pt_regs *regs) { return __perf_event_overflow(event, nmi, 1, data, regs); } /* * Generic software event infrastructure */ /* * 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 = atomic64_read(&hwc->period_left); if (val < 0) return 0; nr = div64_u64(period + val, period); offset = nr * period; val -= offset; if (atomic64_cmpxchg(&hwc->period_left, old, val) != old) goto again; return nr; } static void perf_swevent_overflow(struct perf_event *event, u64 overflow, int nmi, struct perf_sample_data *data, struct pt_regs *regs) { struct hw_perf_event *hwc = &event->hw; int throttle = 0; data->period = event->hw.last_period; if (!overflow) overflow = perf_swevent_set_period(event); if (hwc->interrupts == MAX_INTERRUPTS) return; for (; overflow; overflow--) { if (__perf_event_overflow(event, nmi, throttle, data, regs)) { /* * We inhibit the overflow from happening when * hwc->interrupts == MAX_INTERRUPTS. */ break; } throttle = 1; } } static void perf_swevent_add(struct perf_event *event, u64 nr, int nmi, struct perf_sample_data *data, struct pt_regs *regs) { struct hw_perf_event *hwc = &event->hw; atomic64_add(nr, &event->count); if (!regs) return; if (!hwc->sample_period) return; if (nr == 1 && hwc->sample_period == 1 && !event->attr.freq) return perf_swevent_overflow(event, 1, nmi, data, regs); if (atomic64_add_negative(nr, &hwc->period_left)) return; perf_swevent_overflow(event, 0, nmi, data, regs); } static int perf_exclude_event(struct perf_event *event, struct pt_regs *regs) { 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 perf_cpu_context *ctx, u64 type, u32 event_id) { struct swevent_hlist *hlist; hlist = rcu_dereference(ctx->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 perf_cpu_context *ctx, 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(ctx->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, int nmi, struct perf_sample_data *data, struct pt_regs *regs) { struct perf_cpu_context *cpuctx; struct perf_event *event; struct hlist_node *node; struct hlist_head *head; cpuctx = &__get_cpu_var(perf_cpu_context); rcu_read_lock(); head = find_swevent_head_rcu(cpuctx, type, event_id); if (!head) goto end; hlist_for_each_entry_rcu(event, node, head, hlist_entry) { if (perf_swevent_match(event, type, event_id, data, regs)) perf_swevent_add(event, nr, nmi, data, regs); } end: rcu_read_unlock(); } int perf_swevent_get_recursion_context(void) { struct perf_cpu_context *cpuctx = &__get_cpu_var(perf_cpu_context); int rctx; if (in_nmi()) rctx = 3; else if (in_irq()) rctx = 2; else if (in_softirq()) rctx = 1; else rctx = 0; if (cpuctx->recursion[rctx]) return -1; cpuctx->recursion[rctx]++; barrier(); return rctx; } EXPORT_SYMBOL_GPL(perf_swevent_get_recursion_context); void inline perf_swevent_put_recursion_context(int rctx) { struct perf_cpu_context *cpuctx = &__get_cpu_var(perf_cpu_context); barrier(); cpuctx->recursion[rctx]--; } void __perf_sw_event(u32 event_id, u64 nr, int nmi, 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); do_perf_sw_event(PERF_TYPE_SOFTWARE, event_id, nr, nmi, &data, regs); perf_swevent_put_recursion_context(rctx); preempt_enable_notrace(); } static void perf_swevent_read(struct perf_event *event) { } static int perf_swevent_enable(struct perf_event *event) { struct hw_perf_event *hwc = &event->hw; struct perf_cpu_context *cpuctx; struct hlist_head *head; cpuctx = &__get_cpu_var(perf_cpu_context); if (hwc->sample_period) { hwc->last_period = hwc->sample_period; perf_swevent_set_period(event); } head = find_swevent_head(cpuctx, event); if (WARN_ON_ONCE(!head)) return -EINVAL; hlist_add_head_rcu(&event->hlist_entry, head); return 0; } static void perf_swevent_disable(struct perf_event *event) { hlist_del_rcu(&event->hlist_entry); } static void perf_swevent_void(struct perf_event *event) { } static int perf_swevent_int(struct perf_event *event) { return 0; } static const struct pmu perf_ops_generic = { .enable = perf_swevent_enable, .disable = perf_swevent_disable, .start = perf_swevent_int, .stop = perf_swevent_void, .read = perf_swevent_read, .unthrottle = perf_swevent_void, /* hwc->interrupts already reset */ }; /* * 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); event->pmu->read(event); perf_sample_data_init(&data, 0); data.period = event->hw.last_period; regs = get_irq_regs(); if (regs && !perf_exclude_event(event, regs)) { if (!(event->attr.exclude_idle && current->pid == 0)) if (perf_event_overflow(event, 0, &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; hrtimer_init(&hwc->hrtimer, CLOCK_MONOTONIC, HRTIMER_MODE_REL); hwc->hrtimer.function = perf_swevent_hrtimer; if (hwc->sample_period) { u64 period; if (hwc->remaining) { if (hwc->remaining < 0) period = 10000; else period = hwc->remaining; hwc->remaining = 0; } else { period = max_t(u64, 10000, hwc->sample_period); } __hrtimer_start_range_ns(&hwc->hrtimer, ns_to_ktime(period), 0, HRTIMER_MODE_REL, 0); } } static void perf_swevent_cancel_hrtimer(struct perf_event *event) { struct hw_perf_event *hwc = &event->hw; if (hwc->sample_period) { ktime_t remaining = hrtimer_get_remaining(&hwc->hrtimer); hwc->remaining = ktime_to_ns(remaining); hrtimer_cancel(&hwc->hrtimer); } } /* * Software event: cpu wall time clock */ static void cpu_clock_perf_event_update(struct perf_event *event) { int cpu = raw_smp_processor_id(); s64 prev; u64 now; now = cpu_clock(cpu); prev = atomic64_xchg(&event->hw.prev_count, now); atomic64_add(now - prev, &event->count); } static int cpu_clock_perf_event_enable(struct perf_event *event) { struct hw_perf_event *hwc = &event->hw; int cpu = raw_smp_processor_id(); atomic64_set(&hwc->prev_count, cpu_clock(cpu)); perf_swevent_start_hrtimer(event); return 0; } static void cpu_clock_perf_event_disable(struct perf_event *event) { perf_swevent_cancel_hrtimer(event); cpu_clock_perf_event_update(event); } static void cpu_clock_perf_event_read(struct perf_event *event) { cpu_clock_perf_event_update(event); } static const struct pmu perf_ops_cpu_clock = { .enable = cpu_clock_perf_event_enable, .disable = cpu_clock_perf_event_disable, .read = cpu_clock_perf_event_read, }; /* * Software event: task time clock */ static void task_clock_perf_event_update(struct perf_event *event, u64 now) { u64 prev; s64 delta; prev = atomic64_xchg(&event->hw.prev_count, now); delta = now - prev; atomic64_add(delta, &event->count); } static int task_clock_perf_event_enable(struct perf_event *event) { struct hw_perf_event *hwc = &event->hw; u64 now; now = event->ctx->time; atomic64_set(&hwc->prev_count, now); perf_swevent_start_hrtimer(event); return 0; } static void task_clock_perf_event_disable(struct perf_event *event) { perf_swevent_cancel_hrtimer(event); task_clock_perf_event_update(event, event->ctx->time); } static void task_clock_perf_event_read(struct perf_event *event) { u64 time; if (!in_nmi()) { update_context_time(event->ctx); time = event->ctx->time; } else { u64 now = perf_clock(); u64 delta = now - event->ctx->timestamp; time = event->ctx->time + delta; } task_clock_perf_event_update(event, time); } static const struct pmu perf_ops_task_clock = { .enable = task_clock_perf_event_enable, .disable = task_clock_perf_event_disable, .read = task_clock_perf_event_read, }; /* Deref the hlist from the update side */ static inline struct swevent_hlist * swevent_hlist_deref(struct perf_cpu_context *cpuctx) { return rcu_dereference_protected(cpuctx->swevent_hlist, lockdep_is_held(&cpuctx->hlist_mutex)); } static void swevent_hlist_release_rcu(struct rcu_head *rcu_head) { struct swevent_hlist *hlist; hlist = container_of(rcu_head, struct swevent_hlist, rcu_head); kfree(hlist); } static void swevent_hlist_release(struct perf_cpu_context *cpuctx) { struct swevent_hlist *hlist = swevent_hlist_deref(cpuctx); if (!hlist) return; rcu_assign_pointer(cpuctx->swevent_hlist, NULL); call_rcu(&hlist->rcu_head, swevent_hlist_release_rcu); } static void swevent_hlist_put_cpu(struct perf_event *event, int cpu) { struct perf_cpu_context *cpuctx = &per_cpu(perf_cpu_context, cpu); mutex_lock(&cpuctx->hlist_mutex); if (!--cpuctx->hlist_refcount) swevent_hlist_release(cpuctx); mutex_unlock(&cpuctx->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 perf_cpu_context *cpuctx = &per_cpu(perf_cpu_context, cpu); int err = 0; mutex_lock(&cpuctx->hlist_mutex); if (!swevent_hlist_deref(cpuctx) && cpu_online(cpu)) { struct swevent_hlist *hlist; hlist = kzalloc(sizeof(*hlist), GFP_KERNEL); if (!hlist) { err = -ENOMEM; goto exit; } rcu_assign_pointer(cpuctx->swevent_hlist, hlist); } cpuctx->hlist_refcount++; exit: mutex_unlock(&cpuctx->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; } #ifdef CONFIG_EVENT_TRACING static const struct pmu perf_ops_tracepoint = { .enable = perf_trace_enable, .disable = perf_trace_disable, .start = perf_swevent_int, .stop = perf_swevent_void, .read = perf_swevent_read, .unthrottle = perf_swevent_void, }; 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) { /* * 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 perf_sample_data data; struct perf_event *event; struct hlist_node *node; struct perf_raw_record raw = { .size = entry_size, .data = record, }; perf_sample_data_init(&data, addr); data.raw = &raw; hlist_for_each_entry_rcu(event, node, head, hlist_entry) { if (perf_tp_event_match(event, &data, regs)) perf_swevent_add(event, count, 1, &data, regs); } 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 const struct pmu *tp_perf_event_init(struct perf_event *event) { int err; /* * Raw tracepoint data is a severe data leak, only allow root to * have these. */ if ((event->attr.sample_type & PERF_SAMPLE_RAW) && perf_paranoid_tracepoint_raw() && !capable(CAP_SYS_ADMIN)) return ERR_PTR(-EPERM); err = perf_trace_init(event); if (err) return NULL; event->destroy = tp_perf_event_destroy; return &perf_ops_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 const struct pmu *tp_perf_event_init(struct perf_event *event) { return NULL; } 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 static void bp_perf_event_destroy(struct perf_event *event) { release_bp_slot(event); } static const struct pmu *bp_perf_event_init(struct perf_event *bp) { int err; err = register_perf_hw_breakpoint(bp); if (err) return ERR_PTR(err); bp->destroy = bp_perf_event_destroy; return &perf_ops_bp; } 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); if (!perf_exclude_event(bp, regs)) perf_swevent_add(bp, 1, 1, &sample, regs); } #else static const struct pmu *bp_perf_event_init(struct perf_event *bp) { return NULL; } void perf_bp_event(struct perf_event *bp, void *regs) { } #endif atomic_t 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); atomic_dec(&perf_swevent_enabled[event_id]); swevent_hlist_put(event); } static const struct pmu *sw_perf_event_init(struct perf_event *event) { const struct pmu *pmu = NULL; u64 event_id = event->attr.config; /* * Software events (currently) can't in general distinguish * between user, kernel and hypervisor events. * However, context switches and cpu migrations are considered * to be kernel events, and page faults are never hypervisor * events. */ switch (event_id) { case PERF_COUNT_SW_CPU_CLOCK: pmu = &perf_ops_cpu_clock; break; case PERF_COUNT_SW_TASK_CLOCK: /* * If the user instantiates this as a per-cpu event, * use the cpu_clock event instead. */ if (event->ctx->task) pmu = &perf_ops_task_clock; else pmu = &perf_ops_cpu_clock; break; case PERF_COUNT_SW_PAGE_FAULTS: case PERF_COUNT_SW_PAGE_FAULTS_MIN: case PERF_COUNT_SW_PAGE_FAULTS_MAJ: case PERF_COUNT_SW_CONTEXT_SWITCHES: case PERF_COUNT_SW_CPU_MIGRATIONS: case PERF_COUNT_SW_ALIGNMENT_FAULTS: case PERF_COUNT_SW_EMULATION_FAULTS: if (!event->parent) { int err; err = swevent_hlist_get(event); if (err) return ERR_PTR(err); atomic_inc(&perf_swevent_enabled[event_id]); event->destroy = sw_perf_event_destroy; } pmu = &perf_ops_generic; break; } return pmu; } /* * Allocate and initialize a event structure */ static struct perf_event * perf_event_alloc(struct perf_event_attr *attr, int cpu, struct perf_event_context *ctx, struct perf_event *group_leader, struct perf_event *parent_event, perf_overflow_handler_t overflow_handler, gfp_t gfpflags) { const struct pmu *pmu; struct perf_event *event; struct hw_perf_event *hwc; long err; event = kzalloc(sizeof(*event), gfpflags); 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_waitqueue_head(&event->waitq); mutex_init(&event->mmap_mutex); event->cpu = cpu; event->attr = *attr; event->group_leader = group_leader; event->pmu = NULL; event->ctx = ctx; event->oncpu = -1; event->parent = parent_event; event->ns = get_pid_ns(current->nsproxy->pid_ns); event->id = atomic64_inc_return(&perf_event_id); event->state = PERF_EVENT_STATE_INACTIVE; if (!overflow_handler && parent_event) overflow_handler = parent_event->overflow_handler; event->overflow_handler = overflow_handler; if (attr->disabled) event->state = PERF_EVENT_STATE_OFF; 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; atomic64_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; switch (attr->type) { case PERF_TYPE_RAW: case PERF_TYPE_HARDWARE: case PERF_TYPE_HW_CACHE: pmu = hw_perf_event_init(event); break; case PERF_TYPE_SOFTWARE: pmu = sw_perf_event_init(event); break; case PERF_TYPE_TRACEPOINT: pmu = tp_perf_event_init(event); break; case PERF_TYPE_BREAKPOINT: pmu = bp_perf_event_init(event); break; default: break; } 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); } event->pmu = pmu; if (!event->parent) { atomic_inc(&nr_events); 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); } 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 the type exists, the corresponding creation will verify * the attr->config. */ if (attr->type >= PERF_TYPE_MAX) return -EINVAL; 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; 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 perf_mmap_data *data = NULL, *old_data = 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 buffer, 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; if (output_event) { /* get the buffer we want to redirect to */ data = perf_mmap_data_get(output_event); if (!data) goto unlock; } old_data = event->data; rcu_assign_pointer(event->data, data); ret = 0; unlock: mutex_unlock(&event->mmap_mutex); if (old_data) perf_mmap_data_put(old_data); 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 *event, *group_leader = NULL, *output_event = NULL; struct perf_event_attr attr; struct perf_event_context *ctx; struct file *event_file = NULL; struct file *group_file = NULL; int event_fd; int fput_needed = 0; int err; /* for future expandability... */ if (flags & ~(PERF_FLAG_FD_NO_GROUP | PERF_FLAG_FD_OUTPUT)) 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; } event_fd = get_unused_fd_flags(O_RDWR); if (event_fd < 0) return event_fd; /* * Get the target context (task or percpu): */ ctx = find_get_context(pid, cpu); if (IS_ERR(ctx)) { err = PTR_ERR(ctx); goto err_fd; } if (group_fd != -1) { group_leader = perf_fget_light(group_fd, &fput_needed); if (IS_ERR(group_leader)) { err = PTR_ERR(group_leader); goto err_put_context; } group_file = group_leader->filp; if (flags & PERF_FLAG_FD_OUTPUT) output_event = group_leader; if (flags & PERF_FLAG_FD_NO_GROUP) group_leader = 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_put_context; /* * Do not allow to attach to a group in a different * task or CPU context: */ if (group_leader->ctx != ctx) goto err_put_context; /* * Only a group leader can be exclusive or pinned */ if (attr.exclusive || attr.pinned) goto err_put_context; } event = perf_event_alloc(&attr, cpu, ctx, group_leader, NULL, NULL, GFP_KERNEL); if (IS_ERR(event)) { err = PTR_ERR(event); goto err_put_context; } if (output_event) { err = perf_event_set_output(event, output_event); if (err) goto err_free_put_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_free_put_context; } event->filp = event_file; WARN_ON_ONCE(ctx->parent_ctx); mutex_lock(&ctx->mutex); perf_install_in_context(ctx, event, cpu); ++ctx->generation; mutex_unlock(&ctx->mutex); event->owner = current; get_task_struct(current); mutex_lock(¤t->perf_event_mutex); list_add_tail(&event->owner_entry, ¤t->perf_event_list); mutex_unlock(¤t->perf_event_mutex); /* * 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(). */ fput_light(group_file, fput_needed); fd_install(event_fd, event_file); return event_fd; err_free_put_context: free_event(event); err_put_context: fput_light(group_file, fput_needed); put_ctx(ctx); 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 * @pid: task to profile */ struct perf_event * perf_event_create_kernel_counter(struct perf_event_attr *attr, int cpu, pid_t pid, perf_overflow_handler_t overflow_handler) { struct perf_event *event; struct perf_event_context *ctx; int err; /* * Get the target context (task or percpu): */ ctx = find_get_context(pid, cpu); if (IS_ERR(ctx)) { err = PTR_ERR(ctx); goto err_exit; } event = perf_event_alloc(attr, cpu, ctx, NULL, NULL, overflow_handler, GFP_KERNEL); if (IS_ERR(event)) { err = PTR_ERR(event); goto err_put_context; } event->filp = NULL; WARN_ON_ONCE(ctx->parent_ctx); mutex_lock(&ctx->mutex); perf_install_in_context(ctx, event, cpu); ++ctx->generation; mutex_unlock(&ctx->mutex); event->owner = current; get_task_struct(current); mutex_lock(¤t->perf_event_mutex); list_add_tail(&event->owner_entry, ¤t->perf_event_list); mutex_unlock(¤t->perf_event_mutex); return event; err_put_context: put_ctx(ctx); err_exit: return ERR_PTR(err); } EXPORT_SYMBOL_GPL(perf_event_create_kernel_counter); /* * 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; /* * 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_ctx, group_leader, parent_event, NULL, GFP_KERNEL); if (IS_ERR(child_event)) return child_event; 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; atomic64_set(&hwc->period_left, sample_period); } child_event->overflow_handler = parent_event->overflow_handler; /* * Link it up in the child's context: */ add_event_to_ctx(child_event, child_ctx); /* * Get a reference to the parent filp - we will fput it * when the child event exits. This is safe to do because * we are in the parent and we know that the filp still * exists and has a nonzero count: */ atomic_long_inc(&parent_event->filp->f_count); /* * 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 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 = atomic64_read(&child_event->count); /* * Add back the child's count to the parent's count: */ atomic64_add(child_val, &parent_event->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. */ fput(parent_event->filp); } static void __perf_event_exit_task(struct perf_event *child_event, struct perf_event_context *child_ctx, struct task_struct *child) { struct perf_event *parent_event; perf_event_remove_from_context(child_event); parent_event = child_event->parent; /* * It can happen that parent exits first, and has events * that are still around due to the child reference. These * events need to be zapped - but otherwise linger. */ if (parent_event) { sync_child_event(child_event, child); free_event(child_event); } } /* * When a child task exits, feed back event values to parent events. */ void perf_event_exit_task(struct task_struct *child) { struct perf_event *child_event, *tmp; struct perf_event_context *child_ctx; unsigned long flags; if (likely(!child->perf_event_ctxp)) { 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 = child->perf_event_ctxp; __perf_event_task_sched_out(child_ctx); /* * 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); child->perf_event_ctxp = 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() * fput(parent_event->filp) * perf_release() * 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); } 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); fput(parent->filp); perf_group_detach(event); list_del_event(event, ctx); free_event(event); } /* * free an unexposed, unused context as created by inheritance by * init_task below, used by fork() in case of fail. */ void perf_event_free_task(struct task_struct *task) { struct perf_event_context *ctx = task->perf_event_ctxp; struct perf_event *event, *tmp; if (!ctx) return; 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); } static int inherit_task_group(struct perf_event *event, struct task_struct *parent, struct perf_event_context *parent_ctx, struct task_struct *child, int *inherited_all) { int ret; struct perf_event_context *child_ctx = child->perf_event_ctxp; if (!event->attr.inherit) { *inherited_all = 0; return 0; } 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 = kzalloc(sizeof(struct perf_event_context), GFP_KERNEL); if (!child_ctx) return -ENOMEM; __perf_event_init_context(child_ctx, child); child->perf_event_ctxp = child_ctx; get_task_struct(child); } 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_task(struct task_struct *child) { 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; int ret = 0; child->perf_event_ctxp = NULL; mutex_init(&child->perf_event_mutex); INIT_LIST_HEAD(&child->perf_event_list); if (likely(!parent->perf_event_ctxp)) 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); /* * 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, &inherited_all); if (ret) break; } list_for_each_entry(event, &parent_ctx->flexible_groups, group_entry) { ret = inherit_task_group(event, parent, parent_ctx, child, &inherited_all); if (ret) break; } child_ctx = child->perf_event_ctxp; 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, it could get * uncloned at any point, but that doesn't matter * because the list of events and the generation * count can't have changed since we took the mutex. */ cloned_ctx = rcu_dereference(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); } mutex_unlock(&parent_ctx->mutex); perf_unpin_context(parent_ctx); return ret; } static void __init perf_event_init_all_cpus(void) { int cpu; struct perf_cpu_context *cpuctx; for_each_possible_cpu(cpu) { cpuctx = &per_cpu(perf_cpu_context, cpu); mutex_init(&cpuctx->hlist_mutex); __perf_event_init_context(&cpuctx->ctx, NULL); } } static void __cpuinit perf_event_init_cpu(int cpu) { struct perf_cpu_context *cpuctx; cpuctx = &per_cpu(perf_cpu_context, cpu); spin_lock(&perf_resource_lock); cpuctx->max_pertask = perf_max_events - perf_reserved_percpu; spin_unlock(&perf_resource_lock); mutex_lock(&cpuctx->hlist_mutex); if (cpuctx->hlist_refcount > 0) { struct swevent_hlist *hlist; hlist = kzalloc(sizeof(*hlist), GFP_KERNEL); WARN_ON_ONCE(!hlist); rcu_assign_pointer(cpuctx->swevent_hlist, hlist); } mutex_unlock(&cpuctx->hlist_mutex); } #ifdef CONFIG_HOTPLUG_CPU static void __perf_event_exit_cpu(void *info) { struct perf_cpu_context *cpuctx = &__get_cpu_var(perf_cpu_context); struct perf_event_context *ctx = &cpuctx->ctx; struct perf_event *event, *tmp; list_for_each_entry_safe(event, tmp, &ctx->pinned_groups, group_entry) __perf_event_remove_from_context(event); list_for_each_entry_safe(event, tmp, &ctx->flexible_groups, group_entry) __perf_event_remove_from_context(event); } static void perf_event_exit_cpu(int cpu) { struct perf_cpu_context *cpuctx = &per_cpu(perf_cpu_context, cpu); struct perf_event_context *ctx = &cpuctx->ctx; mutex_lock(&cpuctx->hlist_mutex); swevent_hlist_release(cpuctx); mutex_unlock(&cpuctx->hlist_mutex); mutex_lock(&ctx->mutex); smp_call_function_single(cpu, __perf_event_exit_cpu, NULL, 1); mutex_unlock(&ctx->mutex); } #else static inline void perf_event_exit_cpu(int cpu) { } #endif static int __cpuinit perf_cpu_notify(struct notifier_block *self, unsigned long action, void *hcpu) { unsigned int cpu = (long)hcpu; switch (action) { case CPU_UP_PREPARE: case CPU_UP_PREPARE_FROZEN: perf_event_init_cpu(cpu); break; case CPU_DOWN_PREPARE: case CPU_DOWN_PREPARE_FROZEN: perf_event_exit_cpu(cpu); break; default: break; } return NOTIFY_OK; } /* * This has to have a higher priority than migration_notifier in sched.c. */ static struct notifier_block __cpuinitdata perf_cpu_nb = { .notifier_call = perf_cpu_notify, .priority = 20, }; void __init perf_event_init(void) { perf_event_init_all_cpus(); perf_cpu_notify(&perf_cpu_nb, (unsigned long)CPU_UP_PREPARE, (void *)(long)smp_processor_id()); perf_cpu_notify(&perf_cpu_nb, (unsigned long)CPU_ONLINE, (void *)(long)smp_processor_id()); register_cpu_notifier(&perf_cpu_nb); } static ssize_t perf_show_reserve_percpu(struct sysdev_class *class, struct sysdev_class_attribute *attr, char *buf) { return sprintf(buf, "%d\n", perf_reserved_percpu); } static ssize_t perf_set_reserve_percpu(struct sysdev_class *class, struct sysdev_class_attribute *attr, const char *buf, size_t count) { struct perf_cpu_context *cpuctx; unsigned long val; int err, cpu, mpt; err = strict_strtoul(buf, 10, &val); if (err) return err; if (val > perf_max_events) return -EINVAL; spin_lock(&perf_resource_lock); perf_reserved_percpu = val; for_each_online_cpu(cpu) { cpuctx = &per_cpu(perf_cpu_context, cpu); raw_spin_lock_irq(&cpuctx->ctx.lock); mpt = min(perf_max_events - cpuctx->ctx.nr_events, perf_max_events - perf_reserved_percpu); cpuctx->max_pertask = mpt; raw_spin_unlock_irq(&cpuctx->ctx.lock); } spin_unlock(&perf_resource_lock); return count; } static ssize_t perf_show_overcommit(struct sysdev_class *class, struct sysdev_class_attribute *attr, char *buf) { return sprintf(buf, "%d\n", perf_overcommit); } static ssize_t perf_set_overcommit(struct sysdev_class *class, struct sysdev_class_attribute *attr, const char *buf, size_t count) { unsigned long val; int err; err = strict_strtoul(buf, 10, &val); if (err) return err; if (val > 1) return -EINVAL; spin_lock(&perf_resource_lock); perf_overcommit = val; spin_unlock(&perf_resource_lock); return count; } static SYSDEV_CLASS_ATTR( reserve_percpu, 0644, perf_show_reserve_percpu, perf_set_reserve_percpu ); static SYSDEV_CLASS_ATTR( overcommit, 0644, perf_show_overcommit, perf_set_overcommit ); static struct attribute *perfclass_attrs[] = { &attr_reserve_percpu.attr, &attr_overcommit.attr, NULL }; static struct attribute_group perfclass_attr_group = { .attrs = perfclass_attrs, .name = "perf_events", }; static int __init perf_event_sysfs_init(void) { return sysfs_create_group(&cpu_sysdev_class.kset.kobj, &perfclass_attr_group); } device_initcall(perf_event_sysfs_init);