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-rw-r--r--kernel/perf_event.c5000
1 files changed, 5000 insertions, 0 deletions
diff --git a/kernel/perf_event.c b/kernel/perf_event.c
new file mode 100644
index 0000000..76ac4db
--- /dev/null
+++ b/kernel/perf_event.c
@@ -0,0 +1,5000 @@
+/*
+ * Performance events core code:
+ *
+ * Copyright (C) 2008 Thomas Gleixner <tglx@linutronix.de>
+ * Copyright (C) 2008-2009 Red Hat, Inc., Ingo Molnar
+ * Copyright (C) 2008-2009 Red Hat, Inc., Peter Zijlstra <pzijlstr@redhat.com>
+ * Copyright © 2009 Paul Mackerras, IBM Corp. <paulus@au1.ibm.com>
+ *
+ * For licensing details see kernel-base/COPYING
+ */
+
+#include <linux/fs.h>
+#include <linux/mm.h>
+#include <linux/cpu.h>
+#include <linux/smp.h>
+#include <linux/file.h>
+#include <linux/poll.h>
+#include <linux/sysfs.h>
+#include <linux/dcache.h>
+#include <linux/percpu.h>
+#include <linux/ptrace.h>
+#include <linux/vmstat.h>
+#include <linux/hardirq.h>
+#include <linux/rculist.h>
+#include <linux/uaccess.h>
+#include <linux/syscalls.h>
+#include <linux/anon_inodes.h>
+#include <linux/kernel_stat.h>
+#include <linux/perf_event.h>
+
+#include <asm/irq_regs.h>
+
+/*
+ * Each CPU has a list of per CPU events:
+ */
+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;
+
+static inline bool perf_paranoid_tracepoint_raw(void)
+{
+ return sysctl_perf_event_paranoid > -1;
+}
+
+static inline bool perf_paranoid_cpu(void)
+{
+ return sysctl_perf_event_paranoid > 0;
+}
+
+static inline bool perf_paranoid_kernel(void)
+{
+ return sysctl_perf_event_paranoid > 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 hw_perf_event_setup(int cpu) { barrier(); }
+void __weak hw_perf_event_setup_online(int cpu) { barrier(); }
+
+int __weak
+hw_perf_group_sched_in(struct perf_event *group_leader,
+ struct perf_cpu_context *cpuctx,
+ struct perf_event_context *ctx, int cpu)
+{
+ return 0;
+}
+
+void __weak perf_event_print_debug(void) { }
+
+static DEFINE_PER_CPU(int, perf_disable_count);
+
+void __perf_disable(void)
+{
+ __get_cpu_var(perf_disable_count)++;
+}
+
+bool __perf_enable(void)
+{
+ return !--__get_cpu_var(perf_disable_count);
+}
+
+void perf_disable(void)
+{
+ __perf_disable();
+ hw_perf_disable();
+}
+
+void perf_enable(void)
+{
+ if (__perf_enable())
+ 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.
+ */
+ spin_lock_irqsave(&ctx->lock, *flags);
+ if (ctx != rcu_dereference(task->perf_event_ctxp)) {
+ spin_unlock_irqrestore(&ctx->lock, *flags);
+ goto retry;
+ }
+
+ if (!atomic_inc_not_zero(&ctx->refcount)) {
+ 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;
+ spin_unlock_irqrestore(&ctx->lock, flags);
+ }
+ return ctx;
+}
+
+static void perf_unpin_context(struct perf_event_context *ctx)
+{
+ unsigned long flags;
+
+ spin_lock_irqsave(&ctx->lock, flags);
+ --ctx->pin_count;
+ spin_unlock_irqrestore(&ctx->lock, flags);
+ put_ctx(ctx);
+}
+
+/*
+ * 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)
+{
+ struct perf_event *group_leader = event->group_leader;
+
+ /*
+ * Depending on whether it is a standalone or sibling event,
+ * add it straight to the context's event list, or to the group
+ * leader's sibling list:
+ */
+ if (group_leader == event)
+ list_add_tail(&event->group_entry, &ctx->group_list);
+ else {
+ list_add_tail(&event->group_entry, &group_leader->sibling_list);
+ group_leader->nr_siblings++;
+ }
+
+ list_add_rcu(&event->event_entry, &ctx->event_list);
+ ctx->nr_events++;
+ if (event->attr.inherit_stat)
+ ctx->nr_stat++;
+}
+
+/*
+ * Remove a event from the lists for its context.
+ * Must be called with ctx->mutex and ctx->lock held.
+ */
+static void
+list_del_event(struct perf_event *event, struct perf_event_context *ctx)
+{
+ struct perf_event *sibling, *tmp;
+
+ if (list_empty(&event->group_entry))
+ return;
+ ctx->nr_events--;
+ if (event->attr.inherit_stat)
+ ctx->nr_stat--;
+
+ list_del_init(&event->group_entry);
+ list_del_rcu(&event->event_entry);
+
+ if (event->group_leader != event)
+ event->group_leader->nr_siblings--;
+
+ /*
+ * If this was a group event with sibling events then
+ * upgrade the siblings to singleton events by adding them
+ * to the context list directly:
+ */
+ list_for_each_entry_safe(sibling, tmp, &event->sibling_list, group_entry) {
+
+ list_move_tail(&sibling->group_entry, &ctx->group_list);
+ sibling->group_leader = sibling;
+ }
+}
+
+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;
+
+ 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();
+ 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 sucessful.
+ */
+ 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);
+
+ 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)) {
+ 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);
+ }
+ spin_unlock_irq(&ctx->lock);
+}
+
+static inline u64 perf_clock(void)
+{
+ return cpu_clock(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;
+
+ event->total_time_enabled = ctx->time - 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);
+}
+
+/*
+ * 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;
+
+ 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;
+ }
+
+ 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.
+ */
+static 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);
+
+ 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) {
+ 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;
+ }
+
+ spin_unlock_irq(&ctx->lock);
+}
+
+static int
+event_sched_in(struct perf_event *event,
+ struct perf_cpu_context *cpuctx,
+ struct perf_event_context *ctx,
+ int cpu)
+{
+ if (event->state <= PERF_EVENT_STATE_OFF)
+ return 0;
+
+ event->state = PERF_EVENT_STATE_ACTIVE;
+ event->oncpu = cpu; /* TODO: put 'cpu' into cpuctx->cpu */
+ /*
+ * 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,
+ int cpu)
+{
+ struct perf_event *event, *partial_group;
+ int ret;
+
+ if (group_event->state == PERF_EVENT_STATE_OFF)
+ return 0;
+
+ ret = hw_perf_group_sched_in(group_event, cpuctx, ctx, cpu);
+ if (ret)
+ return ret < 0 ? ret : 0;
+
+ if (event_sched_in(group_event, cpuctx, ctx, cpu))
+ 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, cpu)) {
+ partial_group = event;
+ goto group_error;
+ }
+ }
+
+ 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);
+
+ return -EAGAIN;
+}
+
+/*
+ * Return 1 for a group consisting entirely of software events,
+ * 0 if the group contains any hardware events.
+ */
+static int is_software_only_group(struct perf_event *leader)
+{
+ struct perf_event *event;
+
+ if (!is_software_event(leader))
+ return 0;
+
+ list_for_each_entry(event, &leader->sibling_list, group_entry)
+ if (!is_software_event(event))
+ return 0;
+
+ return 1;
+}
+
+/*
+ * 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 (is_software_only_group(event))
+ 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);
+ 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 cpu = smp_processor_id();
+ 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;
+ }
+
+ 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);
+
+ /*
+ * 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, cpu);
+
+ 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();
+
+ 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 sucessful.
+ */
+ smp_call_function_single(cpu, __perf_install_in_context,
+ event, 1);
+ return;
+ }
+
+retry:
+ task_oncpu_function_call(task, __perf_install_in_context,
+ event);
+
+ spin_lock_irq(&ctx->lock);
+ /*
+ * we need to retry the smp call.
+ */
+ if (ctx->is_active && list_empty(&event->group_entry)) {
+ 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);
+ 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;
+ }
+
+ 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 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,
+ smp_processor_id());
+ else
+ err = event_sched_in(event, cpuctx, ctx,
+ smp_processor_id());
+ 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:
+ 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.
+ */
+static 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;
+ }
+
+ 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:
+ spin_unlock_irq(&ctx->lock);
+ task_oncpu_function_call(task, __perf_event_enable, event);
+
+ 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:
+ 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;
+}
+
+void __perf_event_sched_out(struct perf_event_context *ctx,
+ struct perf_cpu_context *cpuctx)
+{
+ struct perf_event *event;
+
+ 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) {
+ list_for_each_entry(event, &ctx->group_list, group_entry) {
+ if (event != event->group_leader)
+ event_sched_out(event, cpuctx, ctx);
+ else
+ group_sched_out(event, cpuctx, ctx);
+ }
+ }
+ perf_enable();
+ out:
+ 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_read(void *event);
+
+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:
+ __perf_event_read(event);
+ break;
+
+ 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;
+
+ 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, int cpu)
+{
+ struct perf_cpu_context *cpuctx = &per_cpu(perf_cpu_context, cpu);
+ struct perf_event_context *ctx = task->perf_event_ctxp;
+ struct perf_event_context *next_ctx;
+ struct perf_event_context *parent;
+ struct pt_regs *regs;
+ int do_switch = 1;
+
+ regs = task_pt_regs(task);
+ perf_sw_event(PERF_COUNT_SW_CONTEXT_SWITCHES, 1, 1, regs, 0);
+
+ if (likely(!ctx || !cpuctx->task_ctx))
+ return;
+
+ update_context_time(ctx);
+
+ 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.
+ */
+ spin_lock(&ctx->lock);
+ 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);
+ }
+ spin_unlock(&next_ctx->lock);
+ spin_unlock(&ctx->lock);
+ }
+ rcu_read_unlock();
+
+ if (do_switch) {
+ __perf_event_sched_out(ctx, cpuctx);
+ cpuctx->task_ctx = NULL;
+ }
+}
+
+/*
+ * Called with IRQs disabled
+ */
+static void __perf_event_task_sched_out(struct perf_event_context *ctx)
+{
+ 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;
+
+ __perf_event_sched_out(ctx, cpuctx);
+ cpuctx->task_ctx = NULL;
+}
+
+/*
+ * Called with IRQs disabled
+ */
+static void perf_event_cpu_sched_out(struct perf_cpu_context *cpuctx)
+{
+ __perf_event_sched_out(&cpuctx->ctx, cpuctx);
+}
+
+static void
+__perf_event_sched_in(struct perf_event_context *ctx,
+ struct perf_cpu_context *cpuctx, int cpu)
+{
+ struct perf_event *event;
+ int can_add_hw = 1;
+
+ 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.
+ */
+ list_for_each_entry(event, &ctx->group_list, group_entry) {
+ if (event->state <= PERF_EVENT_STATE_OFF ||
+ !event->attr.pinned)
+ continue;
+ if (event->cpu != -1 && event->cpu != cpu)
+ continue;
+
+ if (event != event->group_leader)
+ event_sched_in(event, cpuctx, ctx, cpu);
+ else {
+ if (group_can_go_on(event, cpuctx, 1))
+ group_sched_in(event, cpuctx, ctx, cpu);
+ }
+
+ /*
+ * 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;
+ }
+ }
+
+ list_for_each_entry(event, &ctx->group_list, group_entry) {
+ /*
+ * Ignore events in OFF or ERROR state, and
+ * ignore pinned events since we did them already.
+ */
+ if (event->state <= PERF_EVENT_STATE_OFF ||
+ event->attr.pinned)
+ continue;
+
+ /*
+ * Listen to the 'cpu' scheduling filter constraint
+ * of events:
+ */
+ if (event->cpu != -1 && event->cpu != cpu)
+ continue;
+
+ if (event != event->group_leader) {
+ if (event_sched_in(event, cpuctx, ctx, cpu))
+ can_add_hw = 0;
+ } else {
+ if (group_can_go_on(event, cpuctx, can_add_hw)) {
+ if (group_sched_in(event, cpuctx, ctx, cpu))
+ can_add_hw = 0;
+ }
+ }
+ }
+ perf_enable();
+ out:
+ spin_unlock(&ctx->lock);
+}
+
+/*
+ * 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, int cpu)
+{
+ struct perf_cpu_context *cpuctx = &per_cpu(perf_cpu_context, cpu);
+ struct perf_event_context *ctx = task->perf_event_ctxp;
+
+ if (likely(!ctx))
+ return;
+ if (cpuctx->task_ctx == ctx)
+ return;
+ __perf_event_sched_in(ctx, cpuctx, cpu);
+ cpuctx->task_ctx = ctx;
+}
+
+static void perf_event_cpu_sched_in(struct perf_cpu_context *cpuctx, int cpu)
+{
+ struct perf_event_context *ctx = &cpuctx->ctx;
+
+ __perf_event_sched_in(ctx, cpuctx, cpu);
+}
+
+#define MAX_INTERRUPTS (~0ULL)
+
+static void perf_log_throttle(struct perf_event *event, int enable);
+
+static void perf_adjust_period(struct perf_event *event, u64 events)
+{
+ struct hw_perf_event *hwc = &event->hw;
+ u64 period, sample_period;
+ s64 delta;
+
+ events *= hwc->sample_period;
+ period = div64_u64(events, event->attr.sample_freq);
+
+ 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;
+}
+
+static void perf_ctx_adjust_freq(struct perf_event_context *ctx)
+{
+ struct perf_event *event;
+ struct hw_perf_event *hwc;
+ u64 interrupts, freq;
+
+ spin_lock(&ctx->lock);
+ list_for_each_entry(event, &ctx->group_list, group_entry) {
+ if (event->state != PERF_EVENT_STATE_ACTIVE)
+ continue;
+
+ hwc = &event->hw;
+
+ interrupts = hwc->interrupts;
+ hwc->interrupts = 0;
+
+ /*
+ * unthrottle events on the tick
+ */
+ if (interrupts == MAX_INTERRUPTS) {
+ perf_log_throttle(event, 1);
+ event->pmu->unthrottle(event);
+ interrupts = 2*sysctl_perf_event_sample_rate/HZ;
+ }
+
+ if (!event->attr.freq || !event->attr.sample_freq)
+ continue;
+
+ /*
+ * if the specified freq < HZ then we need to skip ticks
+ */
+ if (event->attr.sample_freq < HZ) {
+ freq = event->attr.sample_freq;
+
+ hwc->freq_count += freq;
+ hwc->freq_interrupts += interrupts;
+
+ if (hwc->freq_count < HZ)
+ continue;
+
+ interrupts = hwc->freq_interrupts;
+ hwc->freq_interrupts = 0;
+ hwc->freq_count -= HZ;
+ } else
+ freq = HZ;
+
+ perf_adjust_period(event, freq * interrupts);
+
+ /*
+ * In order to avoid being stalled by an (accidental) huge
+ * sample period, force reset the sample period if we didn't
+ * get any events in this freq period.
+ */
+ if (!interrupts) {
+ perf_disable();
+ event->pmu->disable(event);
+ atomic64_set(&hwc->period_left, 0);
+ event->pmu->enable(event);
+ perf_enable();
+ }
+ }
+ spin_unlock(&ctx->lock);
+}
+
+/*
+ * Round-robin a context's events:
+ */
+static void rotate_ctx(struct perf_event_context *ctx)
+{
+ struct perf_event *event;
+
+ if (!ctx->nr_events)
+ return;
+
+ spin_lock(&ctx->lock);
+ /*
+ * Rotate the first entry last (works just fine for group events too):
+ */
+ perf_disable();
+ list_for_each_entry(event, &ctx->group_list, group_entry) {
+ list_move_tail(&event->group_entry, &ctx->group_list);
+ break;
+ }
+ perf_enable();
+
+ spin_unlock(&ctx->lock);
+}
+
+void perf_event_task_tick(struct task_struct *curr, int cpu)
+{
+ struct perf_cpu_context *cpuctx;
+ struct perf_event_context *ctx;
+
+ if (!atomic_read(&nr_events))
+ return;
+
+ cpuctx = &per_cpu(perf_cpu_context, cpu);
+ ctx = curr->perf_event_ctxp;
+
+ perf_ctx_adjust_freq(&cpuctx->ctx);
+ if (ctx)
+ perf_ctx_adjust_freq(ctx);
+
+ perf_event_cpu_sched_out(cpuctx);
+ if (ctx)
+ __perf_event_task_sched_out(ctx);
+
+ rotate_ctx(&cpuctx->ctx);
+ if (ctx)
+ rotate_ctx(ctx);
+
+ perf_event_cpu_sched_in(cpuctx, cpu);
+ if (ctx)
+ perf_event_task_sched_in(curr, cpu);
+}
+
+/*
+ * 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;
+
+ local_irq_save(flags);
+ ctx = task->perf_event_ctxp;
+ if (!ctx || !ctx->nr_events)
+ goto out;
+
+ __perf_event_task_sched_out(ctx);
+
+ spin_lock(&ctx->lock);
+
+ list_for_each_entry(event, &ctx->group_list, group_entry) {
+ if (!event->attr.enable_on_exec)
+ continue;
+ event->attr.enable_on_exec = 0;
+ if (event->state >= PERF_EVENT_STATE_INACTIVE)
+ continue;
+ __perf_event_mark_enabled(event, ctx);
+ enabled = 1;
+ }
+
+ /*
+ * Unclone this context if we enabled any event.
+ */
+ if (enabled)
+ unclone_ctx(ctx);
+
+ spin_unlock(&ctx->lock);
+
+ perf_event_task_sched_in(task, smp_processor_id());
+ 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;
+ unsigned long flags;
+
+ /*
+ * 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;
+
+ local_irq_save(flags);
+ if (ctx->is_active)
+ update_context_time(ctx);
+ event->pmu->read(event);
+ update_event_times(event);
+ local_irq_restore(flags);
+}
+
+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) {
+ update_event_times(event);
+ }
+
+ 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)
+{
+ memset(ctx, 0, sizeof(*ctx));
+ spin_lock_init(&ctx->lock);
+ mutex_init(&ctx->mutex);
+ INIT_LIST_HEAD(&ctx->group_list);
+ 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 cpu is not a wildcard then this is a percpu event:
+ */
+ if (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 > num_possible_cpus())
+ 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_isset(cpu, cpu_online_map))
+ 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);
+ spin_unlock_irqrestore(&ctx->lock, flags);
+ }
+
+ if (!ctx) {
+ ctx = kmalloc(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 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);
+ kfree(event);
+}
+
+static void perf_pending_sync(struct perf_event *event);
+
+static void free_event(struct perf_event *event)
+{
+ perf_pending_sync(event);
+
+ if (!event->parent) {
+ atomic_dec(&nr_events);
+ if (event->attr.mmap)
+ 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->output) {
+ fput(event->output->filp);
+ event->output = NULL;
+ }
+
+ if (event->destroy)
+ event->destroy(event);
+
+ put_ctx(event->ctx);
+ call_rcu(&event->rcu_head, free_event_rcu);
+}
+
+/*
+ * 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;
+ struct perf_event_context *ctx = event->ctx;
+
+ file->private_data = NULL;
+
+ WARN_ON_ONCE(ctx->parent_ctx);
+ mutex_lock(&ctx->mutex);
+ perf_event_remove_from_context(event);
+ 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;
+}
+
+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;
+}
+
+static u64 perf_event_read_value(struct perf_event *event)
+{
+ struct perf_event *child;
+ u64 total = 0;
+
+ total += perf_event_read(event);
+ list_for_each_entry(child, &event->child_list, child_list)
+ total += perf_event_read(child);
+
+ return total;
+}
+
+static int perf_event_read_entry(struct perf_event *event,
+ u64 read_format, char __user *buf)
+{
+ int n = 0, count = 0;
+ u64 values[2];
+
+ values[n++] = perf_event_read_value(event);
+ if (read_format & PERF_FORMAT_ID)
+ values[n++] = primary_event_id(event);
+
+ count = n * sizeof(u64);
+
+ if (copy_to_user(buf, values, count))
+ return -EFAULT;
+
+ return count;
+}
+
+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, err = -EFAULT;
+ u64 values[3];
+
+ values[n++] = 1 + leader->nr_siblings;
+ if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED) {
+ values[n++] = leader->total_time_enabled +
+ atomic64_read(&leader->child_total_time_enabled);
+ }
+ if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING) {
+ values[n++] = leader->total_time_running +
+ atomic64_read(&leader->child_total_time_running);
+ }
+
+ size = n * sizeof(u64);
+
+ if (copy_to_user(buf, values, size))
+ return -EFAULT;
+
+ err = perf_event_read_entry(leader, read_format, buf + size);
+ if (err < 0)
+ return err;
+
+ size += err;
+
+ list_for_each_entry(sub, &leader->sibling_list, group_entry) {
+ err = perf_event_read_entry(sub, read_format,
+ buf + size);
+ if (err < 0)
+ return err;
+
+ size += err;
+ }
+
+ return size;
+}
+
+static int perf_event_read_one(struct perf_event *event,
+ u64 read_format, char __user *buf)
+{
+ u64 values[4];
+ int n = 0;
+
+ values[n++] = perf_event_read_value(event);
+ 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);
+
+ 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);
+ mutex_lock(&event->child_mutex);
+ 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);
+ mutex_unlock(&event->child_mutex);
+
+ 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;
+
+ 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:
+ spin_unlock_irq(&ctx->lock);
+
+ return ret;
+}
+
+int perf_event_set_output(struct perf_event *event, int output_fd);
+
+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:
+ return perf_event_set_output(event, 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(&current->perf_event_mutex);
+ list_for_each_entry(event, &current->perf_event_list, owner_entry)
+ perf_event_for_each_child(event, perf_event_enable);
+ mutex_unlock(&current->perf_event_mutex);
+
+ return 0;
+}
+
+int perf_event_task_disable(void)
+{
+ struct perf_event *event;
+
+ mutex_lock(&current->perf_event_mutex);
+ list_for_each_entry(event, &current->perf_event_list, owner_entry)
+ perf_event_for_each_child(event, perf_event_disable);
+ mutex_unlock(&current->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();
+}
+
+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 == 0) {
+ vmf->page = virt_to_page(data->user_page);
+ } else {
+ int nr = vmf->pgoff - 1;
+
+ if ((unsigned)nr > data->nr_pages)
+ goto unlock;
+
+ if (vmf->flags & FAULT_FLAG_WRITE)
+ goto unlock;
+
+ vmf->page = virt_to_page(data->data_pages[nr]);
+ }
+
+ 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 int perf_mmap_data_alloc(struct perf_event *event, int nr_pages)
+{
+ struct perf_mmap_data *data;
+ unsigned long size;
+ int i;
+
+ WARN_ON(atomic_read(&event->mmap_count));
+
+ size = sizeof(struct perf_mmap_data);
+ size += nr_pages * sizeof(void *);
+
+ data = kzalloc(size, GFP_KERNEL);
+ if (!data)
+ goto fail;
+
+ data->user_page = (void *)get_zeroed_page(GFP_KERNEL);
+ if (!data->user_page)
+ goto fail_user_page;
+
+ for (i = 0; i < nr_pages; i++) {
+ data->data_pages[i] = (void *)get_zeroed_page(GFP_KERNEL);
+ if (!data->data_pages[i])
+ goto fail_data_pages;
+ }
+
+ data->nr_pages = nr_pages;
+ atomic_set(&data->lock, -1);
+
+ if (event->attr.watermark) {
+ data->watermark = min_t(long, PAGE_SIZE * nr_pages,
+ event->attr.wakeup_watermark);
+ }
+ if (!data->watermark)
+ data->watermark = max(PAGE_SIZE, PAGE_SIZE * nr_pages / 4);
+
+ rcu_assign_pointer(event->data, data);
+
+ return 0;
+
+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 -ENOMEM;
+}
+
+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 rcu_head *rcu_head)
+{
+ struct perf_mmap_data *data;
+ int i;
+
+ data = container_of(rcu_head, struct perf_mmap_data, rcu_head);
+
+ 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 void perf_mmap_data_free(struct perf_event *event)
+{
+ struct perf_mmap_data *data = event->data;
+
+ WARN_ON(atomic_read(&event->mmap_count));
+
+ rcu_assign_pointer(event->data, NULL);
+ call_rcu(&data->rcu_head, __perf_mmap_data_free);
+}
+
+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;
+
+ WARN_ON_ONCE(event->ctx->parent_ctx);
+ if (atomic_dec_and_mutex_lock(&event->mmap_count, &event->mmap_mutex)) {
+ struct user_struct *user = current_user();
+
+ atomic_long_sub(event->data->nr_pages + 1, &user->locked_vm);
+ vma->vm_mm->locked_vm -= event->data->nr_locked;
+ perf_mmap_data_free(event);
+ mutex_unlock(&event->mmap_mutex);
+ }
+}
+
+static 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;
+ unsigned long vma_size;
+ unsigned long nr_pages;
+ long user_extra, extra;
+ int ret = 0;
+
+ 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->output) {
+ ret = -EINVAL;
+ goto unlock;
+ }
+
+ if (atomic_inc_not_zero(&event->mmap_count)) {
+ if (nr_pages != event->data->nr_pages)
+ 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 = current->signal->rlim[RLIMIT_MEMLOCK].rlim_cur;
+ 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);
+ ret = perf_mmap_data_alloc(event, nr_pages);
+ if (ret)
+ goto unlock;
+
+ atomic_set(&event->mmap_count, 1);
+ atomic_long_add(user_extra, &user->locked_vm);
+ vma->vm_mm->locked_vm += extra;
+ event->data->nr_locked = extra;
+ if (vma->vm_flags & VM_WRITE)
+ event->data->writable = 1;
+
+unlock:
+ 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 = {
+ .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;
+}
+
+/*
+ * 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 = (data->nr_pages << PAGE_SHIFT) - 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);
+}
+
+/*
+ * Curious locking construct.
+ *
+ * We need to ensure a later event_id doesn't publish a head when a former
+ * event_id isn't done writing. However since we need to deal with NMIs we
+ * cannot fully serialize things.
+ *
+ * What we do is serialize between CPUs so we only have to deal with NMI
+ * nesting on a single CPU.
+ *
+ * We only publish the head (and generate a wakeup) when the outer-most
+ * event_id completes.
+ */
+static void perf_output_lock(struct perf_output_handle *handle)
+{
+ struct perf_mmap_data *data = handle->data;
+ int cpu;
+
+ handle->locked = 0;
+
+ local_irq_save(handle->flags);
+ cpu = smp_processor_id();
+
+ if (in_nmi() && atomic_read(&data->lock) == cpu)
+ return;
+
+ while (atomic_cmpxchg(&data->lock, -1, cpu) != -1)
+ cpu_relax();
+
+ handle->locked = 1;
+}
+
+static void perf_output_unlock(struct perf_output_handle *handle)
+{
+ struct perf_mmap_data *data = handle->data;
+ unsigned long head;
+ int cpu;
+
+ data->done_head = data->head;
+
+ if (!handle->locked)
+ goto out;
+
+again:
+ /*
+ * The xchg implies a full barrier that ensures all writes are done
+ * before we publish the new head, matched by a rmb() in userspace when
+ * reading this position.
+ */
+ while ((head = atomic_long_xchg(&data->done_head, 0)))
+ data->user_page->data_head = head;
+
+ /*
+ * NMI can happen here, which means we can miss a done_head update.
+ */
+
+ cpu = atomic_xchg(&data->lock, -1);
+ WARN_ON_ONCE(cpu != smp_processor_id());
+
+ /*
+ * Therefore we have to validate we did not indeed do so.
+ */
+ if (unlikely(atomic_long_read(&data->done_head))) {
+ /*
+ * Since we had it locked, we can lock it again.
+ */
+ while (atomic_cmpxchg(&data->lock, -1, cpu) != -1)
+ cpu_relax();
+
+ goto again;
+ }
+
+ if (atomic_xchg(&data->wakeup, 0))
+ perf_output_wakeup(handle);
+out:
+ local_irq_restore(handle->flags);
+}
+
+void perf_output_copy(struct perf_output_handle *handle,
+ const void *buf, unsigned int len)
+{
+ unsigned int pages_mask;
+ unsigned int offset;
+ unsigned int size;
+ void **pages;
+
+ offset = handle->offset;
+ pages_mask = handle->data->nr_pages - 1;
+ pages = handle->data->data_pages;
+
+ do {
+ unsigned int page_offset;
+ int nr;
+
+ nr = (offset >> PAGE_SHIFT) & pages_mask;
+ page_offset = offset & (PAGE_SIZE - 1);
+ size = min_t(unsigned int, PAGE_SIZE - page_offset, len);
+
+ memcpy(pages[nr] + page_offset, buf, size);
+
+ len -= size;
+ buf += size;
+ offset += size;
+ } while (len);
+
+ handle->offset = offset;
+
+ /*
+ * Check we didn't copy past our reservation window, taking the
+ * possible unsigned int wrap into account.
+ */
+ WARN_ON_ONCE(((long)(handle->head - handle->offset)) < 0);
+}
+
+int perf_output_begin(struct perf_output_handle *handle,
+ struct perf_event *event, unsigned int size,
+ int nmi, int sample)
+{
+ struct perf_event *output_event;
+ 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;
+
+ output_event = rcu_dereference(event->output);
+ if (output_event)
+ event = output_event;
+
+ 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 fail;
+
+ have_lost = atomic_read(&data->lost);
+ if (have_lost)
+ size += sizeof(lost_event);
+
+ perf_output_lock(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 = atomic_long_read(&data->head);
+ head += size;
+ if (unlikely(!perf_output_space(data, tail, offset, head)))
+ goto fail;
+ } while (atomic_long_cmpxchg(&data->head, offset, head) != offset);
+
+ handle->offset = offset;
+ handle->head = head;
+
+ if (head - tail > data->watermark)
+ atomic_set(&data->wakeup, 1);
+
+ 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 = atomic_xchg(&data->lost, 0);
+
+ perf_output_put(handle, lost_event);
+ }
+
+ return 0;
+
+fail:
+ atomic_inc(&data->lost);
+ perf_output_unlock(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 = atomic_inc_return(&data->events);
+ if (events >= wakeup_events) {
+ atomic_sub(wakeup_events, &data->events);
+ atomic_set(&data->wakeup, 1);
+ }
+ }
+
+ perf_output_unlock(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.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;
+ int size;
+ struct task_struct *task = task_event->task;
+ int 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);
+
+ task_event->event_id.time = perf_clock();
+
+ perf_output_put(&handle, task_event->event_id);
+
+ perf_output_end(&handle);
+}
+
+static int perf_event_task_match(struct perf_event *event)
+{
+ if (event->attr.comm || event->attr.mmap || 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;
+
+ if (system_state != SYSTEM_RUNNING || list_empty(&ctx->event_list))
+ return;
+
+ rcu_read_lock();
+ list_for_each_entry_rcu(event, &ctx->event_list, event_entry) {
+ if (perf_event_task_match(event))
+ perf_event_task_output(event, task_event);
+ }
+ rcu_read_unlock();
+}
+
+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;
+
+ cpuctx = &get_cpu_var(perf_cpu_context);
+ perf_event_task_ctx(&cpuctx->ctx, task_event);
+ put_cpu_var(perf_cpu_context);
+
+ rcu_read_lock();
+ if (!ctx)
+ ctx = rcu_dereference(task_event->task->perf_event_ctxp);
+ if (ctx)
+ perf_event_task_ctx(ctx, task_event);
+ 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 */
+ },
+ };
+
+ 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->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;
+
+ if (system_state != SYSTEM_RUNNING || list_empty(&ctx->event_list))
+ return;
+
+ rcu_read_lock();
+ list_for_each_entry_rcu(event, &ctx->event_list, event_entry) {
+ if (perf_event_comm_match(event))
+ perf_event_comm_output(event, comm_event);
+ }
+ rcu_read_unlock();
+}
+
+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));
+ strncpy(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;
+
+ cpuctx = &get_cpu_var(perf_cpu_context);
+ perf_event_comm_ctx(&cpuctx->ctx, comm_event);
+ put_cpu_var(perf_cpu_context);
+
+ rcu_read_lock();
+ /*
+ * doesn't really matter which of the child contexts the
+ * events ends up in.
+ */
+ ctx = rcu_dereference(current->perf_event_ctxp);
+ if (ctx)
+ perf_event_comm_ctx(ctx, comm_event);
+ 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)
+{
+ if (event->attr.mmap)
+ return 1;
+
+ return 0;
+}
+
+static void perf_event_mmap_ctx(struct perf_event_context *ctx,
+ struct perf_mmap_event *mmap_event)
+{
+ struct perf_event *event;
+
+ if (system_state != SYSTEM_RUNNING || list_empty(&ctx->event_list))
+ return;
+
+ rcu_read_lock();
+ list_for_each_entry_rcu(event, &ctx->event_list, event_entry) {
+ if (perf_event_mmap_match(event, mmap_event))
+ perf_event_mmap_output(event, mmap_event);
+ }
+ rcu_read_unlock();
+}
+
+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;
+ }
+
+ 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;
+
+ cpuctx = &get_cpu_var(perf_cpu_context);
+ perf_event_mmap_ctx(&cpuctx->ctx, mmap_event);
+ put_cpu_var(perf_cpu_context);
+
+ rcu_read_lock();
+ /*
+ * doesn't really matter which of the child contexts the
+ * events ends up in.
+ */
+ ctx = rcu_dereference(current->perf_event_ctxp);
+ if (ctx)
+ perf_event_mmap_ctx(ctx, mmap_event);
+ 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 = 0,
+ /* .size */
+ },
+ /* .pid */
+ /* .tid */
+ .start = vma->vm_start,
+ .len = vma->vm_end - vma->vm_start,
+ .pgoff = vma->vm_pgoff,
+ },
+ };
+
+ 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_stamp;
+
+ hwc->freq_stamp = now;
+
+ if (delta > 0 && delta < TICK_NSEC)
+ perf_adjust_period(event, NSEC_PER_SEC / (int)delta);
+ }
+
+ /*
+ * 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);
+ }
+
+ 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,
+ int nmi, struct perf_sample_data *data,
+ struct pt_regs *regs)
+{
+ struct hw_perf_event *hwc = &event->hw;
+ int throttle = 0;
+ u64 overflow;
+
+ data->period = event->hw.last_period;
+ 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_unthrottle(struct perf_event *event)
+{
+ /*
+ * Nothing to do, we already reset hwc->interrupts.
+ */
+}
+
+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 (!hwc->sample_period)
+ return;
+
+ if (!regs)
+ return;
+
+ if (!atomic64_add_negative(nr, &hwc->period_left))
+ perf_swevent_overflow(event, nmi, data, regs);
+}
+
+static int perf_swevent_is_counting(struct perf_event *event)
+{
+ /*
+ * The event is active, we're good!
+ */
+ if (event->state == PERF_EVENT_STATE_ACTIVE)
+ return 1;
+
+ /*
+ * The event is off/error, not counting.
+ */
+ if (event->state != PERF_EVENT_STATE_INACTIVE)
+ return 0;
+
+ /*
+ * The event is inactive, if the context is active
+ * we're part of a group that didn't make it on the 'pmu',
+ * not counting.
+ */
+ if (event->ctx->is_active)
+ return 0;
+
+ /*
+ * We're inactive and the context is too, this means the
+ * task is scheduled out, we're counting events that happen
+ * to us, like migration events.
+ */
+ return 1;
+}
+
+static int perf_swevent_match(struct perf_event *event,
+ enum perf_type_id type,
+ u32 event_id, struct pt_regs *regs)
+{
+ if (!perf_swevent_is_counting(event))
+ return 0;
+
+ if (event->attr.type != type)
+ return 0;
+ if (event->attr.config != event_id)
+ return 0;
+
+ if (regs) {
+ if (event->attr.exclude_user && user_mode(regs))
+ return 0;
+
+ if (event->attr.exclude_kernel && !user_mode(regs))
+ return 0;
+ }
+
+ return 1;
+}
+
+static void perf_swevent_ctx_event(struct perf_event_context *ctx,
+ enum perf_type_id type,
+ u32 event_id, u64 nr, int nmi,
+ struct perf_sample_data *data,
+ struct pt_regs *regs)
+{
+ struct perf_event *event;
+
+ if (system_state != SYSTEM_RUNNING || list_empty(&ctx->event_list))
+ return;
+
+ rcu_read_lock();
+ list_for_each_entry_rcu(event, &ctx->event_list, event_entry) {
+ if (perf_swevent_match(event, type, event_id, regs))
+ perf_swevent_add(event, nr, nmi, data, regs);
+ }
+ rcu_read_unlock();
+}
+
+static int *perf_swevent_recursion_context(struct perf_cpu_context *cpuctx)
+{
+ if (in_nmi())
+ return &cpuctx->recursion[3];
+
+ if (in_irq())
+ return &cpuctx->recursion[2];
+
+ if (in_softirq())
+ return &cpuctx->recursion[1];
+
+ return &cpuctx->recursion[0];
+}
+
+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 = &get_cpu_var(perf_cpu_context);
+ int *recursion = perf_swevent_recursion_context(cpuctx);
+ struct perf_event_context *ctx;
+
+ if (*recursion)
+ goto out;
+
+ (*recursion)++;
+ barrier();
+
+ perf_swevent_ctx_event(&cpuctx->ctx, type, event_id,
+ nr, nmi, data, regs);
+ rcu_read_lock();
+ /*
+ * doesn't really matter which of the child contexts the
+ * events ends up in.
+ */
+ ctx = rcu_dereference(current->perf_event_ctxp);
+ if (ctx)
+ perf_swevent_ctx_event(ctx, type, event_id, nr, nmi, data, regs);
+ rcu_read_unlock();
+
+ barrier();
+ (*recursion)--;
+
+out:
+ put_cpu_var(perf_cpu_context);
+}
+
+void __perf_sw_event(u32 event_id, u64 nr, int nmi,
+ struct pt_regs *regs, u64 addr)
+{
+ struct perf_sample_data data = {
+ .addr = addr,
+ };
+
+ do_perf_sw_event(PERF_TYPE_SOFTWARE, event_id, nr, nmi,
+ &data, regs);
+}
+
+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;
+
+ if (hwc->sample_period) {
+ hwc->last_period = hwc->sample_period;
+ perf_swevent_set_period(event);
+ }
+ return 0;
+}
+
+static void perf_swevent_disable(struct perf_event *event)
+{
+}
+
+static const struct pmu perf_ops_generic = {
+ .enable = perf_swevent_enable,
+ .disable = perf_swevent_disable,
+ .read = perf_swevent_read,
+ .unthrottle = perf_swevent_unthrottle,
+};
+
+/*
+ * 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);
+
+ data.addr = 0;
+ regs = get_irq_regs();
+ /*
+ * In case we exclude kernel IPs or are somehow not in interrupt
+ * context, provide the next best thing, the user IP.
+ */
+ if ((event->attr.exclude_kernel || !regs) &&
+ !event->attr.exclude_user)
+ regs = task_pt_regs(current);
+
+ if (regs) {
+ 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;
+}
+
+/*
+ * 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_read(&event->hw.prev_count);
+ atomic64_set(&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));
+ hrtimer_init(&hwc->hrtimer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
+ hwc->hrtimer.function = perf_swevent_hrtimer;
+ if (hwc->sample_period) {
+ u64 period = max_t(u64, 10000, hwc->sample_period);
+ __hrtimer_start_range_ns(&hwc->hrtimer,
+ ns_to_ktime(period), 0,
+ HRTIMER_MODE_REL, 0);
+ }
+
+ return 0;
+}
+
+static void cpu_clock_perf_event_disable(struct perf_event *event)
+{
+ if (event->hw.sample_period)
+ hrtimer_cancel(&event->hw.hrtimer);
+ 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);
+ hrtimer_init(&hwc->hrtimer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
+ hwc->hrtimer.function = perf_swevent_hrtimer;
+ if (hwc->sample_period) {
+ u64 period = max_t(u64, 10000, hwc->sample_period);
+ __hrtimer_start_range_ns(&hwc->hrtimer,
+ ns_to_ktime(period), 0,
+ HRTIMER_MODE_REL, 0);
+ }
+
+ return 0;
+}
+
+static void task_clock_perf_event_disable(struct perf_event *event)
+{
+ if (event->hw.sample_period)
+ hrtimer_cancel(&event->hw.hrtimer);
+ 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,
+};
+
+#ifdef CONFIG_EVENT_PROFILE
+void perf_tp_event(int event_id, u64 addr, u64 count, void *record,
+ int entry_size)
+{
+ struct perf_raw_record raw = {
+ .size = entry_size,
+ .data = record,
+ };
+
+ struct perf_sample_data data = {
+ .addr = addr,
+ .raw = &raw,
+ };
+
+ struct pt_regs *regs = get_irq_regs();
+
+ if (!regs)
+ regs = task_pt_regs(current);
+
+ do_perf_sw_event(PERF_TYPE_TRACEPOINT, event_id, count, 1,
+ &data, regs);
+}
+EXPORT_SYMBOL_GPL(perf_tp_event);
+
+extern int ftrace_profile_enable(int);
+extern void ftrace_profile_disable(int);
+
+static void tp_perf_event_destroy(struct perf_event *event)
+{
+ ftrace_profile_disable(event->attr.config);
+}
+
+static const struct pmu *tp_perf_event_init(struct perf_event *event)
+{
+ /*
+ * 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);
+
+ if (ftrace_profile_enable(event->attr.config))
+ return NULL;
+
+ event->destroy = tp_perf_event_destroy;
+
+ return &perf_ops_generic;
+}
+#else
+static const struct pmu *tp_perf_event_init(struct perf_event *event)
+{
+ return NULL;
+}
+#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]);
+}
+
+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:
+ if (!event->parent) {
+ 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,
+ 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 (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;
+
+ 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)
+ 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 || attr->__reserved_2 || attr->__reserved_3)
+ 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;
+}
+
+int perf_event_set_output(struct perf_event *event, int output_fd)
+{
+ struct perf_event *output_event = NULL;
+ struct file *output_file = NULL;
+ struct perf_event *old_output;
+ int fput_needed = 0;
+ int ret = -EINVAL;
+
+ if (!output_fd)
+ goto set;
+
+ output_file = fget_light(output_fd, &fput_needed);
+ if (!output_file)
+ return -EBADF;
+
+ if (output_file->f_op != &perf_fops)
+ goto out;
+
+ output_event = output_file->private_data;
+
+ /* Don't chain output fds */
+ if (output_event->output)
+ goto out;
+
+ /* Don't set an output fd when we already have an output channel */
+ if (event->data)
+ goto out;
+
+ atomic_long_inc(&output_file->f_count);
+
+set:
+ mutex_lock(&event->mmap_mutex);
+ old_output = event->output;
+ rcu_assign_pointer(event->output, output_event);
+ mutex_unlock(&event->mmap_mutex);
+
+ if (old_output) {
+ /*
+ * we need to make sure no existing perf_output_*()
+ * is still referencing this event.
+ */
+ synchronize_rcu();
+ fput(old_output->filp);
+ }
+
+ ret = 0;
+out:
+ fput_light(output_file, fput_needed);
+ 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;
+ struct perf_event_attr attr;
+ struct perf_event_context *ctx;
+ struct file *event_file = NULL;
+ struct file *group_file = NULL;
+ int fput_needed = 0;
+ int fput_needed2 = 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;
+ }
+
+ /*
+ * Get the target context (task or percpu):
+ */
+ ctx = find_get_context(pid, cpu);
+ if (IS_ERR(ctx))
+ return PTR_ERR(ctx);
+
+ /*
+ * Look up the group leader (we will attach this event to it):
+ */
+ group_leader = NULL;
+ if (group_fd != -1 && !(flags & PERF_FLAG_FD_NO_GROUP)) {
+ err = -EINVAL;
+ group_file = fget_light(group_fd, &fput_needed);
+ if (!group_file)
+ goto err_put_context;
+ if (group_file->f_op != &perf_fops)
+ goto err_put_context;
+
+ group_leader = group_file->private_data;
+ /*
+ * 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, GFP_KERNEL);
+ err = PTR_ERR(event);
+ if (IS_ERR(event))
+ goto err_put_context;
+
+ err = anon_inode_getfd("[perf_event]", &perf_fops, event, 0);
+ if (err < 0)
+ goto err_free_put_context;
+
+ event_file = fget_light(err, &fput_needed2);
+ if (!event_file)
+ goto err_free_put_context;
+
+ if (flags & PERF_FLAG_FD_OUTPUT) {
+ err = perf_event_set_output(event, group_fd);
+ if (err)
+ goto err_fput_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(&current->perf_event_mutex);
+ list_add_tail(&event->owner_entry, &current->perf_event_list);
+ mutex_unlock(&current->perf_event_mutex);
+
+err_fput_free_put_context:
+ fput_light(event_file, fput_needed2);
+
+err_free_put_context:
+ if (err < 0)
+ kfree(event);
+
+err_put_context:
+ if (err < 0)
+ put_ctx(ctx);
+
+ fput_light(group_file, fput_needed);
+
+ return err;
+}
+
+/*
+ * 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,
+ 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)
+ child_event->hw.sample_period = parent_event->hw.sample_period;
+
+ /*
+ * 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;
+
+ update_event_times(child_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.
+ */
+ 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);
+ 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_nested(&child_ctx->mutex, SINGLE_DEPTH_NESTING);
+
+again:
+ list_for_each_entry_safe(child_event, tmp, &child_ctx->group_list,
+ 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->group_list))
+ goto again;
+
+ mutex_unlock(&child_ctx->mutex);
+
+ put_ctx(child_ctx);
+}
+
+/*
+ * 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->group_list, group_entry) {
+ struct perf_event *parent = event->parent;
+
+ if (WARN_ON_ONCE(!parent))
+ continue;
+
+ mutex_lock(&parent->child_mutex);
+ list_del_init(&event->child_list);
+ mutex_unlock(&parent->child_mutex);
+
+ fput(parent->filp);
+
+ list_del_event(event, ctx);
+ free_event(event);
+ }
+
+ if (!list_empty(&ctx->group_list))
+ goto again;
+
+ mutex_unlock(&ctx->mutex);
+
+ put_ctx(ctx);
+}
+
+/*
+ * 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;
+
+ /*
+ * 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 = kmalloc(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);
+
+ /*
+ * 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_rcu(event, &parent_ctx->event_list, event_entry) {
+ if (event != event->group_leader)
+ continue;
+
+ if (!event->attr.inherit) {
+ inherited_all = 0;
+ continue;
+ }
+
+ ret = inherit_group(event, parent, parent_ctx,
+ child, child_ctx);
+ if (ret) {
+ inherited_all = 0;
+ break;
+ }
+ }
+
+ if (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 __cpuinit perf_event_init_cpu(int cpu)
+{
+ struct perf_cpu_context *cpuctx;
+
+ cpuctx = &per_cpu(perf_cpu_context, cpu);
+ __perf_event_init_context(&cpuctx->ctx, NULL);
+
+ spin_lock(&perf_resource_lock);
+ cpuctx->max_pertask = perf_max_events - perf_reserved_percpu;
+ spin_unlock(&perf_resource_lock);
+
+ hw_perf_event_setup(cpu);
+}
+
+#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->group_list, 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(&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_ONLINE:
+ case CPU_ONLINE_FROZEN:
+ hw_perf_event_setup_online(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_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, char *buf)
+{
+ return sprintf(buf, "%d\n", perf_reserved_percpu);
+}
+
+static ssize_t
+perf_set_reserve_percpu(struct sysdev_class *class,
+ 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);
+ 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;
+ spin_unlock_irq(&cpuctx->ctx.lock);
+ }
+ spin_unlock(&perf_resource_lock);
+
+ return count;
+}
+
+static ssize_t perf_show_overcommit(struct sysdev_class *class, char *buf)
+{
+ return sprintf(buf, "%d\n", perf_overcommit);
+}
+
+static ssize_t
+perf_set_overcommit(struct sysdev_class *class, 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);
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