[PATCH 01/20] perf: Start the massive restructuring

Borislav Petkov
2010-11-04T15:38:52Z

[-- Warning: decoded text below may be mangled, UTF-8 assumed --]
[-- Attachment #1: Type: text/plain; charset=UTF-8, Size: 288281 bytes --]

From: Borislav Petkov <borislav.petkov@amd.com>

mv kernel/perf_event.c -> kernel/events/core.c. From there, all other
sensible splitting can happen.

Signed-off-by: Borislav Petkov <borislav.petkov@amd.com>
---
kernel/Makefile | 5 +-
kernel/events/Makefile | 5 +
kernel/events/core.c | 5895 ++++++++++++++++++++++++++++++++++++++++++++++++
kernel/perf_event.c | 5895 ------------------------------------------------
4 files changed, 5904 insertions(+), 5896 deletions(-)
create mode 100644 kernel/events/Makefile
create mode 100644 kernel/events/core.c
delete mode 100644 kernel/perf_event.c

diff --git a/kernel/Makefile b/kernel/Makefile
index 0b72d1a..5830059 100644
--- a/kernel/Makefile
+++ b/kernel/Makefile
@@ -100,7 +100,10 @@ obj-$(CONFIG_TRACING) += trace/
obj-$(CONFIG_X86_DS) += trace/
obj-$(CONFIG_RING_BUFFER) += trace/
obj-$(CONFIG_SMP) += sched_cpupri.o
-obj-$(CONFIG_PERF_EVENTS) += perf_event.o
+
+# obj-$(CONFIG_PERF_EVENTS) += perf_event.o
+obj-$(CONFIG_PERF_EVENTS) += events/
+
obj-$(CONFIG_HAVE_HW_BREAKPOINT) += hw_breakpoint.o
obj-$(CONFIG_USER_RETURN_NOTIFIER) += user-return-notifier.o
obj-$(CONFIG_PADATA) += padata.o
diff --git a/kernel/events/Makefile b/kernel/events/Makefile
new file mode 100644
index 0000000..5445cbf
--- /dev/null
+++ b/kernel/events/Makefile
@@ -0,0 +1,5 @@
+ifdef CONFIG_FUNCTION_TRACER
+CFLAGS_REMOVE_perf_event.o = -pg
+endif
+
+obj-y += core.o
diff --git a/kernel/events/core.c b/kernel/events/core.c
new file mode 100644
index 0000000..b98bed3
--- /dev/null
+++ b/kernel/events/core.c
@@ -0,0 +1,5895 @@
+/*
+ * 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/slab.h>
+#include <linux/hash.h>
+#include <linux/sysfs.h>
+#include <linux/dcache.h>
+#include <linux/percpu.h>
+#include <linux/ptrace.h>
+#include <linux/vmstat.h>
+#include <linux/vmalloc.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 <linux/ftrace_event.h>
+#include <linux/hw_breakpoint.h>
+
+#include <asm/irq_regs.h>
+
+/*
+ * Each CPU has a list of per CPU events:
+ */
+static DEFINE_PER_CPU(struct perf_cpu_context, perf_cpu_context);
+
+int perf_max_events __read_mostly = 1;
+static int perf_reserved_percpu __read_mostly;
+static int perf_overcommit __read_mostly = 1;
+
+static atomic_t nr_events __read_mostly;
+static atomic_t nr_mmap_events __read_mostly;
+static atomic_t nr_comm_events __read_mostly;
+static atomic_t nr_task_events __read_mostly;
+
+/*
+ * perf event paranoia level:
+ * -1 - not paranoid at all
+ * 0 - disallow raw tracepoint access for unpriv
+ * 1 - disallow cpu events for unpriv
+ * 2 - disallow kernel profiling for unpriv
+ */
+int sysctl_perf_event_paranoid __read_mostly = 1;
+
+int sysctl_perf_event_mlock __read_mostly = 512; /* 'free' kb per user */
+
+/*
+ * max perf event sample rate
+ */
+int sysctl_perf_event_sample_rate __read_mostly = 100000;
+
+static atomic64_t perf_event_id;
+
+/*
+ * Lock for (sysadmin-configurable) event reservations:
+ */
+static DEFINE_SPINLOCK(perf_resource_lock);
+
+/*
+ * Architecture provided APIs - weak aliases:
+ */
+extern __weak const struct pmu *hw_perf_event_init(struct perf_event *event)
+{
+ return NULL;
+}
+
+void __weak hw_perf_disable(void) { barrier(); }
+void __weak hw_perf_enable(void) { barrier(); }
+
+void __weak perf_event_print_debug(void) { }
+
+static DEFINE_PER_CPU(int, perf_disable_count);
+
+void perf_disable(void)
+{
+ if (!__get_cpu_var(perf_disable_count)++)
+ hw_perf_disable();
+}
+
+void perf_enable(void)
+{
+ if (!--__get_cpu_var(perf_disable_count))
+ hw_perf_enable();
+}
+
+static void get_ctx(struct perf_event_context *ctx)
+{
+ WARN_ON(!atomic_inc_not_zero(&ctx->refcount));
+}
+
+static void free_ctx(struct rcu_head *head)
+{
+ struct perf_event_context *ctx;
+
+ ctx = container_of(head, struct perf_event_context, rcu_head);
+ kfree(ctx);
+}
+
+static void put_ctx(struct perf_event_context *ctx)
+{
+ if (atomic_dec_and_test(&ctx->refcount)) {
+ if (ctx->parent_ctx)
+ put_ctx(ctx->parent_ctx);
+ if (ctx->task)
+ put_task_struct(ctx->task);
+ call_rcu(&ctx->rcu_head, free_ctx);
+ }
+}
+
+static void unclone_ctx(struct perf_event_context *ctx)
+{
+ if (ctx->parent_ctx) {
+ put_ctx(ctx->parent_ctx);
+ ctx->parent_ctx = NULL;
+ }
+}
+
+/*
+ * If we inherit events we want to return the parent event id
+ * to userspace.
+ */
+static u64 primary_event_id(struct perf_event *event)
+{
+ u64 id = event->id;
+
+ if (event->parent)
+ id = event->parent->id;
+
+ return id;
+}
+
+/*
+ * Get the perf_event_context for a task and lock it.
+ * This has to cope with with the fact that until it is locked,
+ * the context could get moved to another task.
+ */
+static struct perf_event_context *
+perf_lock_task_context(struct task_struct *task, unsigned long *flags)
+{
+ struct perf_event_context *ctx;
+
+ rcu_read_lock();
+ retry:
+ ctx = rcu_dereference(task->perf_event_ctxp);
+ if (ctx) {
+ /*
+ * If this context is a clone of another, it might
+ * get swapped for another underneath us by
+ * perf_event_task_sched_out, though the
+ * rcu_read_lock() protects us from any context
+ * getting freed. Lock the context and check if it
+ * got swapped before we could get the lock, and retry
+ * if so. If we locked the right context, then it
+ * can't get swapped on us any more.
+ */
+ raw_spin_lock_irqsave(&ctx->lock, *flags);
+ if (ctx != rcu_dereference(task->perf_event_ctxp)) {
+ raw_spin_unlock_irqrestore(&ctx->lock, *flags);
+ goto retry;
+ }
+
+ if (!atomic_inc_not_zero(&ctx->refcount)) {
+ raw_spin_unlock_irqrestore(&ctx->lock, *flags);
+ ctx = NULL;
+ }
+ }
+ rcu_read_unlock();
+ return ctx;
+}
+
+/*
+ * Get the context for a task and increment its pin_count so it
+ * can't get swapped to another task. This also increments its
+ * reference count so that the context can't get freed.
+ */
+static struct perf_event_context *perf_pin_task_context(struct task_struct *task)
+{
+ struct perf_event_context *ctx;
+ unsigned long flags;
+
+ ctx = perf_lock_task_context(task, &flags);
+ if (ctx) {
+ ++ctx->pin_count;
+ raw_spin_unlock_irqrestore(&ctx->lock, flags);
+ }
+ return ctx;
+}
+
+static void perf_unpin_context(struct perf_event_context *ctx)
+{
+ unsigned long flags;
+
+ raw_spin_lock_irqsave(&ctx->lock, flags);
+ --ctx->pin_count;
+ raw_spin_unlock_irqrestore(&ctx->lock, flags);
+ put_ctx(ctx);
+}
+
+static inline u64 perf_clock(void)
+{
+ return local_clock();
+}
+
+/*
+ * Update the record of the current time in a context.
+ */
+static void update_context_time(struct perf_event_context *ctx)
+{
+ u64 now = perf_clock();
+
+ ctx->time += now - ctx->timestamp;
+ ctx->timestamp = now;
+}
+
+/*
+ * Update the total_time_enabled and total_time_running fields for a event.
+ */
+static void update_event_times(struct perf_event *event)
+{
+ struct perf_event_context *ctx = event->ctx;
+ u64 run_end;
+
+ if (event->state < PERF_EVENT_STATE_INACTIVE ||
+ event->group_leader->state < PERF_EVENT_STATE_INACTIVE)
+ return;
+
+ if (ctx->is_active)
+ run_end = ctx->time;
+ else
+ run_end = event->tstamp_stopped;
+
+ event->total_time_enabled = run_end - event->tstamp_enabled;
+
+ if (event->state == PERF_EVENT_STATE_INACTIVE)
+ run_end = event->tstamp_stopped;
+ else
+ run_end = ctx->time;
+
+ event->total_time_running = run_end - event->tstamp_running;
+}
+
+/*
+ * Update total_time_enabled and total_time_running for all events in a group.
+ */
+static void update_group_times(struct perf_event *leader)
+{
+ struct perf_event *event;
+
+ update_event_times(leader);
+ list_for_each_entry(event, &leader->sibling_list, group_entry)
+ update_event_times(event);
+}
+
+static struct list_head *
+ctx_group_list(struct perf_event *event, struct perf_event_context *ctx)
+{
+ if (event->attr.pinned)
+ return &ctx->pinned_groups;
+ else
+ return &ctx->flexible_groups;
+}
+
+/*
+ * Add a event from the lists for its context.
+ * Must be called with ctx->mutex and ctx->lock held.
+ */
+static void
+list_add_event(struct perf_event *event, struct perf_event_context *ctx)
+{
+ WARN_ON_ONCE(event->attach_state & PERF_ATTACH_CONTEXT);
+ event->attach_state |= PERF_ATTACH_CONTEXT;
+
+ /*
+ * If we're a stand alone event or group leader, we go to the context
+ * list, group events are kept attached to the group so that
+ * perf_group_detach can, at all times, locate all siblings.
+ */
+ if (event->group_leader == event) {
+ struct list_head *list;
+
+ if (is_software_event(event))
+ event->group_flags |= PERF_GROUP_SOFTWARE;
+
+ list = ctx_group_list(event, ctx);
+ list_add_tail(&event->group_entry, list);
+ }
+
+ list_add_rcu(&event->event_entry, &ctx->event_list);
+ ctx->nr_events++;
+ if (event->attr.inherit_stat)
+ ctx->nr_stat++;
+}
+
+static void perf_group_attach(struct perf_event *event)
+{
+ struct perf_event *group_leader = event->group_leader;
+
+ WARN_ON_ONCE(event->attach_state & PERF_ATTACH_GROUP);
+ event->attach_state |= PERF_ATTACH_GROUP;
+
+ if (group_leader == event)
+ return;
+
+ if (group_leader->group_flags & PERF_GROUP_SOFTWARE &&
+ !is_software_event(event))
+ group_leader->group_flags &= ~PERF_GROUP_SOFTWARE;
+
+ list_add_tail(&event->group_entry, &group_leader->sibling_list);
+ group_leader->nr_siblings++;
+}
+
+/*
+ * Remove a event from the lists for its context.
+ * Must be called with ctx->mutex and ctx->lock held.
+ */
+static void
+list_del_event(struct perf_event *event, struct perf_event_context *ctx)
+{
+ /*
+ * We can have double detach due to exit/hot-unplug + close.
+ */
+ if (!(event->attach_state & PERF_ATTACH_CONTEXT))
+ return;
+
+ event->attach_state &= ~PERF_ATTACH_CONTEXT;
+
+ ctx->nr_events--;
+ if (event->attr.inherit_stat)
+ ctx->nr_stat--;
+
+ list_del_rcu(&event->event_entry);
+
+ if (event->group_leader == event)
+ list_del_init(&event->group_entry);
+
+ update_group_times(event);
+
+ /*
+ * If event was in error state, then keep it
+ * that way, otherwise bogus counts will be
+ * returned on read(). The only way to get out
+ * of error state is by explicit re-enabling
+ * of the event
+ */
+ if (event->state > PERF_EVENT_STATE_OFF)
+ event->state = PERF_EVENT_STATE_OFF;
+}
+
+static void perf_group_detach(struct perf_event *event)
+{
+ struct perf_event *sibling, *tmp;
+ struct list_head *list = NULL;
+
+ /*
+ * We can have double detach due to exit/hot-unplug + close.
+ */
+ if (!(event->attach_state & PERF_ATTACH_GROUP))
+ return;
+
+ event->attach_state &= ~PERF_ATTACH_GROUP;
+
+ /*
+ * If this is a sibling, remove it from its group.
+ */
+ if (event->group_leader != event) {
+ list_del_init(&event->group_entry);
+ event->group_leader->nr_siblings--;
+ return;
+ }
+
+ if (!list_empty(&event->group_entry))
+ list = &event->group_entry;
+
+ /*
+ * If this was a group event with sibling events then
+ * upgrade the siblings to singleton events by adding them
+ * to whatever list we are on.
+ */
+ list_for_each_entry_safe(sibling, tmp, &event->sibling_list, group_entry) {
+ if (list)
+ list_move_tail(&sibling->group_entry, list);
+ sibling->group_leader = sibling;
+
+ /* Inherit group flags from the previous leader */
+ sibling->group_flags = event->group_flags;
+ }
+}
+
+static inline int
+event_filter_match(struct perf_event *event)
+{
+ return event->cpu == -1 || event->cpu == smp_processor_id();
+}
+
+static void
+event_sched_out(struct perf_event *event,
+ struct perf_cpu_context *cpuctx,
+ struct perf_event_context *ctx)
+{
+ u64 delta;
+ /*
+ * An event which could not be activated because of
+ * filter mismatch still needs to have its timings
+ * maintained, otherwise bogus information is return
+ * via read() for time_enabled, time_running:
+ */
+ if (event->state == PERF_EVENT_STATE_INACTIVE
+ && !event_filter_match(event)) {
+ delta = ctx->time - event->tstamp_stopped;
+ event->tstamp_running += delta;
+ event->tstamp_stopped = ctx->time;
+ }
+
+ 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;
+ int state = group_event->state;
+
+ event_sched_out(group_event, cpuctx, ctx);
+
+ /*
+ * Schedule out siblings (if any):
+ */
+ list_for_each_entry(event, &group_event->sibling_list, group_entry)
+ event_sched_out(event, cpuctx, ctx);
+
+ if (state == PERF_EVENT_STATE_ACTIVE && group_event->attr.exclusive)
+ cpuctx->exclusive = 0;
+}
+
+/*
+ * Cross CPU call to remove a performance event
+ *
+ * We disable the event on the hardware level first. After that we
+ * remove it from the context list.
+ */
+static void __perf_event_remove_from_context(void *info)
+{
+ struct perf_cpu_context *cpuctx = &__get_cpu_var(perf_cpu_context);
+ struct perf_event *event = info;
+ struct perf_event_context *ctx = event->ctx;
+
+ /*
+ * If this is a task context, we need to check whether it is
+ * the current task context of this cpu. If not it has been
+ * scheduled out before the smp call arrived.
+ */
+ if (ctx->task && cpuctx->task_ctx != ctx)
+ return;
+
+ raw_spin_lock(&ctx->lock);
+ /*
+ * Protect the list operation against NMI by disabling the
+ * events on a global level.
+ */
+ perf_disable();
+
+ event_sched_out(event, cpuctx, ctx);
+
+ list_del_event(event, ctx);
+
+ if (!ctx->task) {
+ /*
+ * Allow more per task events with respect to the
+ * reservation:
+ */
+ cpuctx->max_pertask =
+ min(perf_max_events - ctx->nr_events,
+ perf_max_events - perf_reserved_percpu);
+ }
+
+ perf_enable();
+ raw_spin_unlock(&ctx->lock);
+}
+
+
+/*
+ * Remove the event from a task's (or a CPU's) list of events.
+ *
+ * Must be called with ctx->mutex held.
+ *
+ * CPU events are removed with a smp call. For task events we only
+ * call when the task is on a CPU.
+ *
+ * If event->ctx is a cloned context, callers must make sure that
+ * every task struct that event->ctx->task could possibly point to
+ * remains valid. This is OK when called from perf_release since
+ * that only calls us on the top-level context, which can't be a clone.
+ * When called from perf_event_exit_task, it's OK because the
+ * context has been detached from its task.
+ */
+static void perf_event_remove_from_context(struct perf_event *event)
+{
+ struct perf_event_context *ctx = event->ctx;
+ struct task_struct *task = ctx->task;
+
+ if (!task) {
+ /*
+ * Per cpu events are removed via an smp call and
+ * the removal is always successful.
+ */
+ smp_call_function_single(event->cpu,
+ __perf_event_remove_from_context,
+ event, 1);
+ return;
+ }
+
+retry:
+ task_oncpu_function_call(task, __perf_event_remove_from_context,
+ event);
+
+ raw_spin_lock_irq(&ctx->lock);
+ /*
+ * If the context is active we need to retry the smp call.
+ */
+ if (ctx->nr_active && !list_empty(&event->group_entry)) {
+ raw_spin_unlock_irq(&ctx->lock);
+ goto retry;
+ }
+
+ /*
+ * The lock prevents that this context is scheduled in so we
+ * can remove the event safely, if the call above did not
+ * succeed.
+ */
+ if (!list_empty(&event->group_entry))
+ list_del_event(event, ctx);
+ raw_spin_unlock_irq(&ctx->lock);
+}
+
+/*
+ * Cross CPU call to disable a performance event
+ */
+static void __perf_event_disable(void *info)
+{
+ struct perf_event *event = info;
+ struct perf_cpu_context *cpuctx = &__get_cpu_var(perf_cpu_context);
+ struct perf_event_context *ctx = event->ctx;
+
+ /*
+ * If this is a per-task event, need to check whether this
+ * event's task is the current task on this cpu.
+ */
+ if (ctx->task && cpuctx->task_ctx != ctx)
+ return;
+
+ raw_spin_lock(&ctx->lock);
+
+ /*
+ * If the event is on, turn it off.
+ * If it is in error state, leave it in error state.
+ */
+ if (event->state >= PERF_EVENT_STATE_INACTIVE) {
+ update_context_time(ctx);
+ update_group_times(event);
+ if (event == event->group_leader)
+ group_sched_out(event, cpuctx, ctx);
+ else
+ event_sched_out(event, cpuctx, ctx);
+ event->state = PERF_EVENT_STATE_OFF;
+ }
+
+ raw_spin_unlock(&ctx->lock);
+}
+
+/*
+ * Disable a event.
+ *
+ * If event->ctx is a cloned context, callers must make sure that
+ * every task struct that event->ctx->task could possibly point to
+ * remains valid. This condition is satisifed when called through
+ * perf_event_for_each_child or perf_event_for_each because they
+ * hold the top-level event's child_mutex, so any descendant that
+ * goes to exit will block in sync_child_event.
+ * When called from perf_pending_event it's OK because event->ctx
+ * is the current context on this CPU and preemption is disabled,
+ * hence we can't get into perf_event_task_sched_out for this context.
+ */
+void perf_event_disable(struct perf_event *event)
+{
+ struct perf_event_context *ctx = event->ctx;
+ struct task_struct *task = ctx->task;
+
+ if (!task) {
+ /*
+ * Disable the event on the cpu that it's on
+ */
+ smp_call_function_single(event->cpu, __perf_event_disable,
+ event, 1);
+ return;
+ }
+
+ retry:
+ task_oncpu_function_call(task, __perf_event_disable, event);
+
+ raw_spin_lock_irq(&ctx->lock);
+ /*
+ * If the event is still active, we need to retry the cross-call.
+ */
+ if (event->state == PERF_EVENT_STATE_ACTIVE) {
+ raw_spin_unlock_irq(&ctx->lock);
+ goto retry;
+ }
+
+ /*
+ * Since we have the lock this context can't be scheduled
+ * in, so we can change the state safely.
+ */
+ if (event->state == PERF_EVENT_STATE_INACTIVE) {
+ update_group_times(event);
+ event->state = PERF_EVENT_STATE_OFF;
+ }
+
+ raw_spin_unlock_irq(&ctx->lock);
+}
+
+static int
+event_sched_in(struct perf_event *event,
+ struct perf_cpu_context *cpuctx,
+ struct perf_event_context *ctx)
+{
+ if (event->state <= PERF_EVENT_STATE_OFF)
+ return 0;
+
+ event->state = PERF_EVENT_STATE_ACTIVE;
+ event->oncpu = smp_processor_id();
+ /*
+ * The new state must be visible before we turn it on in the hardware:
+ */
+ smp_wmb();
+
+ if (event->pmu->enable(event)) {
+ event->state = PERF_EVENT_STATE_INACTIVE;
+ event->oncpu = -1;
+ return -EAGAIN;
+ }
+
+ event->tstamp_running += ctx->time - event->tstamp_stopped;
+
+ if (!is_software_event(event))
+ cpuctx->active_oncpu++;
+ ctx->nr_active++;
+
+ if (event->attr.exclusive)
+ cpuctx->exclusive = 1;
+
+ return 0;
+}
+
+static int
+group_sched_in(struct perf_event *group_event,
+ struct perf_cpu_context *cpuctx,
+ struct perf_event_context *ctx)
+{
+ struct perf_event *event, *partial_group = NULL;
+ const struct pmu *pmu = group_event->pmu;
+ bool txn = false;
+
+ if (group_event->state == PERF_EVENT_STATE_OFF)
+ return 0;
+
+ /* Check if group transaction availabe */
+ if (pmu->start_txn)
+ txn = true;
+
+ if (txn)
+ pmu->start_txn(pmu);
+
+ if (event_sched_in(group_event, cpuctx, ctx)) {
+ if (txn)
+ pmu->cancel_txn(pmu);
+ return -EAGAIN;
+ }
+
+ /*
+ * Schedule in siblings as one group (if any):
+ */
+ list_for_each_entry(event, &group_event->sibling_list, group_entry) {
+ if (event_sched_in(event, cpuctx, ctx)) {
+ partial_group = event;
+ goto group_error;
+ }
+ }
+
+ if (!txn || !pmu->commit_txn(pmu))
+ return 0;
+
+group_error:
+ /*
+ * Groups can be scheduled in as one unit only, so undo any
+ * partial group before returning:
+ */
+ list_for_each_entry(event, &group_event->sibling_list, group_entry) {
+ if (event == partial_group)
+ break;
+ event_sched_out(event, cpuctx, ctx);
+ }
+ event_sched_out(group_event, cpuctx, ctx);
+
+ if (txn)
+ pmu->cancel_txn(pmu);
+
+ return -EAGAIN;
+}
+
+/*
+ * Work out whether we can put this event group on the CPU now.
+ */
+static int group_can_go_on(struct perf_event *event,
+ struct perf_cpu_context *cpuctx,
+ int can_add_hw)
+{
+ /*
+ * Groups consisting entirely of software events can always go on.
+ */
+ if (event->group_flags & PERF_GROUP_SOFTWARE)
+ return 1;
+ /*
+ * If an exclusive group is already on, no other hardware
+ * events can go on.
+ */
+ if (cpuctx->exclusive)
+ return 0;
+ /*
+ * If this group is exclusive and there are already
+ * events on the CPU, it can't go on.
+ */
+ if (event->attr.exclusive && cpuctx->active_oncpu)
+ return 0;
+ /*
+ * Otherwise, try to add it if all previous groups were able
+ * to go on.
+ */
+ return can_add_hw;
+}
+
+static void add_event_to_ctx(struct perf_event *event,
+ struct perf_event_context *ctx)
+{
+ list_add_event(event, ctx);
+ perf_group_attach(event);
+ event->tstamp_enabled = ctx->time;
+ event->tstamp_running = ctx->time;
+ event->tstamp_stopped = ctx->time;
+}
+
+/*
+ * Cross CPU call to install and enable a performance event
+ *
+ * Must be called with ctx->mutex held
+ */
+static void __perf_install_in_context(void *info)
+{
+ struct perf_cpu_context *cpuctx = &__get_cpu_var(perf_cpu_context);
+ struct perf_event *event = info;
+ struct perf_event_context *ctx = event->ctx;
+ struct perf_event *leader = event->group_leader;
+ int err;
+
+ /*
+ * If this is a task context, we need to check whether it is
+ * the current task context of this cpu. If not it has been
+ * scheduled out before the smp call arrived.
+ * Or possibly this is the right context but it isn't
+ * on this cpu because it had no events.
+ */
+ if (ctx->task && cpuctx->task_ctx != ctx) {
+ if (cpuctx->task_ctx || ctx->task != current)
+ return;
+ cpuctx->task_ctx = ctx;
+ }
+
+ raw_spin_lock(&ctx->lock);
+ ctx->is_active = 1;
+ update_context_time(ctx);
+
+ /*
+ * Protect the list operation against NMI by disabling the
+ * events on a global level. NOP for non NMI based events.
+ */
+ perf_disable();
+
+ add_event_to_ctx(event, ctx);
+
+ if (event->cpu != -1 && event->cpu != smp_processor_id())
+ goto unlock;
+
+ /*
+ * Don't put the event on if it is disabled or if
+ * it is in a group and the group isn't on.
+ */
+ if (event->state != PERF_EVENT_STATE_INACTIVE ||
+ (leader != event && leader->state != PERF_EVENT_STATE_ACTIVE))
+ goto unlock;
+
+ /*
+ * An exclusive event can't go on if there are already active
+ * hardware events, and no hardware event can go on if there
+ * is already an exclusive event on.
+ */
+ if (!group_can_go_on(event, cpuctx, 1))
+ err = -EEXIST;
+ else
+ err = event_sched_in(event, cpuctx, ctx);
+
+ if (err) {
+ /*
+ * This event couldn't go on. If it is in a group
+ * then we have to pull the whole group off.
+ * If the event group is pinned then put it in error state.
+ */
+ if (leader != event)
+ group_sched_out(leader, cpuctx, ctx);
+ if (leader->attr.pinned) {
+ update_group_times(leader);
+ leader->state = PERF_EVENT_STATE_ERROR;
+ }
+ }
+
+ if (!err && !ctx->task && cpuctx->max_pertask)
+ cpuctx->max_pertask--;
+
+ unlock:
+ perf_enable();
+
+ raw_spin_unlock(&ctx->lock);
+}
+
+/*
+ * Attach a performance event to a context
+ *
+ * First we add the event to the list with the hardware enable bit
+ * in event->hw_config cleared.
+ *
+ * If the event is attached to a task which is on a CPU we use a smp
+ * call to enable it in the task context. The task might have been
+ * scheduled away, but we check this in the smp call again.
+ *
+ * Must be called with ctx->mutex held.
+ */
+static void
+perf_install_in_context(struct perf_event_context *ctx,
+ struct perf_event *event,
+ int cpu)
+{
+ struct task_struct *task = ctx->task;
+
+ if (!task) {
+ /*
+ * Per cpu events are installed via an smp call and
+ * the install is always successful.
+ */
+ smp_call_function_single(cpu, __perf_install_in_context,
+ event, 1);
+ return;
+ }
+
+retry:
+ task_oncpu_function_call(task, __perf_install_in_context,
+ event);
+
+ raw_spin_lock_irq(&ctx->lock);
+ /*
+ * we need to retry the smp call.
+ */
+ if (ctx->is_active && list_empty(&event->group_entry)) {
+ raw_spin_unlock_irq(&ctx->lock);
+ goto retry;
+ }
+
+ /*
+ * The lock prevents that this context is scheduled in so we
+ * can add the event safely, if it the call above did not
+ * succeed.
+ */
+ if (list_empty(&event->group_entry))
+ add_event_to_ctx(event, ctx);
+ raw_spin_unlock_irq(&ctx->lock);
+}
+
+/*
+ * Put a event into inactive state and update time fields.
+ * Enabling the leader of a group effectively enables all
+ * the group members that aren't explicitly disabled, so we
+ * have to update their ->tstamp_enabled also.
+ * Note: this works for group members as well as group leaders
+ * since the non-leader members' sibling_lists will be empty.
+ */
+static void __perf_event_mark_enabled(struct perf_event *event,
+ struct perf_event_context *ctx)
+{
+ struct perf_event *sub;
+
+ event->state = PERF_EVENT_STATE_INACTIVE;
+ event->tstamp_enabled = ctx->time - event->total_time_enabled;
+ list_for_each_entry(sub, &event->sibling_list, group_entry)
+ if (sub->state >= PERF_EVENT_STATE_INACTIVE)
+ sub->tstamp_enabled =
+ ctx->time - sub->total_time_enabled;
+}
+
+/*
+ * Cross CPU call to enable a performance event
+ */
+static void __perf_event_enable(void *info)
+{
+ struct perf_event *event = info;
+ struct perf_cpu_context *cpuctx = &__get_cpu_var(perf_cpu_context);
+ struct perf_event_context *ctx = event->ctx;
+ struct perf_event *leader = event->group_leader;
+ int err;
+
+ /*
+ * If this is a per-task event, need to check whether this
+ * event's task is the current task on this cpu.
+ */
+ if (ctx->task && cpuctx->task_ctx != ctx) {
+ if (cpuctx->task_ctx || ctx->task != current)
+ return;
+ cpuctx->task_ctx = ctx;
+ }
+
+ raw_spin_lock(&ctx->lock);
+ ctx->is_active = 1;
+ update_context_time(ctx);
+
+ if (event->state >= PERF_EVENT_STATE_INACTIVE)
+ goto unlock;
+ __perf_event_mark_enabled(event, ctx);
+
+ if (event->cpu != -1 && event->cpu != smp_processor_id())
+ goto unlock;
+
+ /*
+ * If the event is in a group and isn't the group leader,
+ * then don't put it on unless the group is on.
+ */
+ if (leader != event && leader->state != PERF_EVENT_STATE_ACTIVE)
+ goto unlock;
+
+ if (!group_can_go_on(event, cpuctx, 1)) {
+ err = -EEXIST;
+ } else {
+ perf_disable();
+ if (event == leader)
+ err = group_sched_in(event, cpuctx, ctx);
+ else
+ err = event_sched_in(event, cpuctx, ctx);
+ perf_enable();
+ }
+
+ if (err) {
+ /*
+ * If this event can't go on and it's part of a
+ * group, then the whole group has to come off.
+ */
+ if (leader != event)
+ group_sched_out(leader, cpuctx, ctx);
+ if (leader->attr.pinned) {
+ update_group_times(leader);
+ leader->state = PERF_EVENT_STATE_ERROR;
+ }
+ }
+
+ unlock:
+ raw_spin_unlock(&ctx->lock);
+}
+
+/*
+ * Enable a event.
+ *
+ * If event->ctx is a cloned context, callers must make sure that
+ * every task struct that event->ctx->task could possibly point to
+ * remains valid. This condition is satisfied when called through
+ * perf_event_for_each_child or perf_event_for_each as described
+ * for perf_event_disable.
+ */
+void perf_event_enable(struct perf_event *event)
+{
+ struct perf_event_context *ctx = event->ctx;
+ struct task_struct *task = ctx->task;
+
+ if (!task) {
+ /*
+ * Enable the event on the cpu that it's on
+ */
+ smp_call_function_single(event->cpu, __perf_event_enable,
+ event, 1);
+ return;
+ }
+
+ raw_spin_lock_irq(&ctx->lock);
+ if (event->state >= PERF_EVENT_STATE_INACTIVE)
+ goto out;
+
+ /*
+ * If the event is in error state, clear that first.
+ * That way, if we see the event in error state below, we
+ * know that it has gone back into error state, as distinct
+ * from the task having been scheduled away before the
+ * cross-call arrived.
+ */
+ if (event->state == PERF_EVENT_STATE_ERROR)
+ event->state = PERF_EVENT_STATE_OFF;
+
+ retry:
+ raw_spin_unlock_irq(&ctx->lock);
+ task_oncpu_function_call(task, __perf_event_enable, event);
+
+ raw_spin_lock_irq(&ctx->lock);
+
+ /*
+ * If the context is active and the event is still off,
+ * we need to retry the cross-call.
+ */
+ if (ctx->is_active && event->state == PERF_EVENT_STATE_OFF)
+ goto retry;
+
+ /*
+ * Since we have the lock this context can't be scheduled
+ * in, so we can change the state safely.
+ */
+ if (event->state == PERF_EVENT_STATE_OFF)
+ __perf_event_mark_enabled(event, ctx);
+
+ out:
+ raw_spin_unlock_irq(&ctx->lock);
+}
+
+static int perf_event_refresh(struct perf_event *event, int refresh)
+{
+ /*
+ * not supported on inherited events
+ */
+ if (event->attr.inherit)
+ return -EINVAL;
+
+ atomic_add(refresh, &event->event_limit);
+ perf_event_enable(event);
+
+ return 0;
+}
+
+enum event_type_t {
+ EVENT_FLEXIBLE = 0x1,
+ EVENT_PINNED = 0x2,
+ EVENT_ALL = EVENT_FLEXIBLE | EVENT_PINNED,
+};
+
+static void ctx_sched_out(struct perf_event_context *ctx,
+ struct perf_cpu_context *cpuctx,
+ enum event_type_t event_type)
+{
+ struct perf_event *event;
+
+ raw_spin_lock(&ctx->lock);
+ ctx->is_active = 0;
+ if (likely(!ctx->nr_events))
+ goto out;
+ update_context_time(ctx);
+
+ perf_disable();
+ if (!ctx->nr_active)
+ goto out_enable;
+
+ if (event_type & EVENT_PINNED)
+ list_for_each_entry(event, &ctx->pinned_groups, group_entry)
+ group_sched_out(event, cpuctx, ctx);
+
+ if (event_type & EVENT_FLEXIBLE)
+ list_for_each_entry(event, &ctx->flexible_groups, group_entry)
+ group_sched_out(event, cpuctx, ctx);
+
+ out_enable:
+ perf_enable();
+ out:
+ raw_spin_unlock(&ctx->lock);
+}
+
+/*
+ * Test whether two contexts are equivalent, i.e. whether they
+ * have both been cloned from the same version of the same context
+ * and they both have the same number of enabled events.
+ * If the number of enabled events is the same, then the set
+ * of enabled events should be the same, because these are both
+ * inherited contexts, therefore we can't access individual events
+ * in them directly with an fd; we can only enable/disable all
+ * events via prctl, or enable/disable all events in a family
+ * via ioctl, which will have the same effect on both contexts.
+ */
+static int context_equiv(struct perf_event_context *ctx1,
+ struct perf_event_context *ctx2)
+{
+ return ctx1->parent_ctx && ctx1->parent_ctx == ctx2->parent_ctx
+ && ctx1->parent_gen == ctx2->parent_gen
+ && !ctx1->pin_count && !ctx2->pin_count;
+}
+
+static void __perf_event_sync_stat(struct perf_event *event,
+ struct perf_event *next_event)
+{
+ u64 value;
+
+ if (!event->attr.inherit_stat)
+ return;
+
+ /*
+ * Update the event value, we cannot use perf_event_read()
+ * because we're in the middle of a context switch and have IRQs
+ * disabled, which upsets smp_call_function_single(), however
+ * we know the event must be on the current CPU, therefore we
+ * don't need to use it.
+ */
+ switch (event->state) {
+ case PERF_EVENT_STATE_ACTIVE:
+ event->pmu->read(event);
+ /* fall-through */
+
+ case PERF_EVENT_STATE_INACTIVE:
+ update_event_times(event);
+ break;
+
+ default:
+ break;
+ }
+
+ /*
+ * In order to keep per-task stats reliable we need to flip the event
+ * values when we flip the contexts.
+ */
+ value = local64_read(&next_event->count);
+ value = local64_xchg(&event->count, value);
+ local64_set(&next_event->count, value);
+
+ swap(event->total_time_enabled, next_event->total_time_enabled);
+ swap(event->total_time_running, next_event->total_time_running);
+
+ /*
+ * Since we swizzled the values, update the user visible data too.
+ */
+ perf_event_update_userpage(event);
+ perf_event_update_userpage(next_event);
+}
+
+#define list_next_entry(pos, member) \
+ list_entry(pos->member.next, typeof(*pos), member)
+
+static void perf_event_sync_stat(struct perf_event_context *ctx,
+ struct perf_event_context *next_ctx)
+{
+ struct perf_event *event, *next_event;
+
+ if (!ctx->nr_stat)
+ return;
+
+ update_context_time(ctx);
+
+ event = list_first_entry(&ctx->event_list,
+ struct perf_event, event_entry);
+
+ next_event = list_first_entry(&next_ctx->event_list,
+ struct perf_event, event_entry);
+
+ while (&event->event_entry != &ctx->event_list &&
+ &next_event->event_entry != &next_ctx->event_list) {
+
+ __perf_event_sync_stat(event, next_event);
+
+ event = list_next_entry(event, event_entry);
+ next_event = list_next_entry(next_event, event_entry);
+ }
+}
+
+/*
+ * Called from scheduler to remove the events of the current task,
+ * with interrupts disabled.
+ *
+ * We stop each event and update the event value in event->count.
+ *
+ * This does not protect us against NMI, but disable()
+ * sets the disabled bit in the control field of event _before_
+ * accessing the event control register. If a NMI hits, then it will
+ * not restart the event.
+ */
+void perf_event_task_sched_out(struct task_struct *task,
+ struct task_struct *next)
+{
+ struct perf_cpu_context *cpuctx = &__get_cpu_var(perf_cpu_context);
+ struct perf_event_context *ctx = task->perf_event_ctxp;
+ struct perf_event_context *next_ctx;
+ struct perf_event_context *parent;
+ int do_switch = 1;
+
+ perf_sw_event(PERF_COUNT_SW_CONTEXT_SWITCHES, 1, 1, NULL, 0);
+
+ if (likely(!ctx || !cpuctx->task_ctx))
+ return;
+
+ rcu_read_lock();
+ parent = rcu_dereference(ctx->parent_ctx);
+ next_ctx = next->perf_event_ctxp;
+ if (parent && next_ctx &&
+ rcu_dereference(next_ctx->parent_ctx) == parent) {
+ /*
+ * Looks like the two contexts are clones, so we might be
+ * able to optimize the context switch. We lock both
+ * contexts and check that they are clones under the
+ * lock (including re-checking that neither has been
+ * uncloned in the meantime). It doesn't matter which
+ * order we take the locks because no other cpu could
+ * be trying to lock both of these tasks.
+ */
+ raw_spin_lock(&ctx->lock);
+ raw_spin_lock_nested(&next_ctx->lock, SINGLE_DEPTH_NESTING);
+ if (context_equiv(ctx, next_ctx)) {
+ /*
+ * XXX do we need a memory barrier of sorts
+ * wrt to rcu_dereference() of perf_event_ctxp
+ */
+ task->perf_event_ctxp = next_ctx;
+ next->perf_event_ctxp = ctx;
+ ctx->task = next;
+ next_ctx->task = task;
+ do_switch = 0;
+
+ perf_event_sync_stat(ctx, next_ctx);
+ }
+ raw_spin_unlock(&next_ctx->lock);
+ raw_spin_unlock(&ctx->lock);
+ }
+ rcu_read_unlock();
+
+ if (do_switch) {
+ ctx_sched_out(ctx, cpuctx, EVENT_ALL);
+ cpuctx->task_ctx = NULL;
+ }
+}
+
+static void task_ctx_sched_out(struct perf_event_context *ctx,
+ enum event_type_t event_type)
+{
+ struct perf_cpu_context *cpuctx = &__get_cpu_var(perf_cpu_context);
+
+ if (!cpuctx->task_ctx)
+ return;
+
+ if (WARN_ON_ONCE(ctx != cpuctx->task_ctx))
+ return;
+
+ ctx_sched_out(ctx, cpuctx, event_type);
+ cpuctx->task_ctx = NULL;
+}
+
+/*
+ * Called with IRQs disabled
+ */
+static void __perf_event_task_sched_out(struct perf_event_context *ctx)
+{
+ task_ctx_sched_out(ctx, EVENT_ALL);
+}
+
+/*
+ * Called with IRQs disabled
+ */
+static void cpu_ctx_sched_out(struct perf_cpu_context *cpuctx,
+ enum event_type_t event_type)
+{
+ ctx_sched_out(&cpuctx->ctx, cpuctx, event_type);
+}
+
+static void
+ctx_pinned_sched_in(struct perf_event_context *ctx,
+ struct perf_cpu_context *cpuctx)
+{
+ struct perf_event *event;
+
+ list_for_each_entry(event, &ctx->pinned_groups, group_entry) {
+ if (event->state <= PERF_EVENT_STATE_OFF)
+ continue;
+ if (event->cpu != -1 && event->cpu != smp_processor_id())
+ continue;
+
+ if (group_can_go_on(event, cpuctx, 1))
+ group_sched_in(event, cpuctx, ctx);
+
+ /*
+ * If this pinned group hasn't been scheduled,
+ * put it in error state.
+ */
+ if (event->state == PERF_EVENT_STATE_INACTIVE) {
+ update_group_times(event);
+ event->state = PERF_EVENT_STATE_ERROR;
+ }
+ }
+}
+
+static void
+ctx_flexible_sched_in(struct perf_event_context *ctx,
+ struct perf_cpu_context *cpuctx)
+{
+ struct perf_event *event;
+ int can_add_hw = 1;
+
+ list_for_each_entry(event, &ctx->flexible_groups, group_entry) {
+ /* Ignore events in OFF or ERROR state */
+ if (event->state <= PERF_EVENT_STATE_OFF)
+ continue;
+ /*
+ * Listen to the 'cpu' scheduling filter constraint
+ * of events:
+ */
+ if (event->cpu != -1 && event->cpu != smp_processor_id())
+ continue;
+
+ if (group_can_go_on(event, cpuctx, can_add_hw))
+ if (group_sched_in(event, cpuctx, ctx))
+ can_add_hw = 0;
+ }
+}
+
+static void
+ctx_sched_in(struct perf_event_context *ctx,
+ struct perf_cpu_context *cpuctx,
+ enum event_type_t event_type)
+{
+ raw_spin_lock(&ctx->lock);
+ ctx->is_active = 1;
+ if (likely(!ctx->nr_events))
+ goto out;
+
+ ctx->timestamp = perf_clock();
+
+ perf_disable();
+
+ /*
+ * First go through the list and put on any pinned groups
+ * in order to give them the best chance of going on.
+ */
+ if (event_type & EVENT_PINNED)
+ ctx_pinned_sched_in(ctx, cpuctx);
+
+ /* Then walk through the lower prio flexible groups */
+ if (event_type & EVENT_FLEXIBLE)
+ ctx_flexible_sched_in(ctx, cpuctx);
+
+ perf_enable();
+ out:
+ raw_spin_unlock(&ctx->lock);
+}
+
+static void cpu_ctx_sched_in(struct perf_cpu_context *cpuctx,
+ enum event_type_t event_type)
+{
+ struct perf_event_context *ctx = &cpuctx->ctx;
+
+ ctx_sched_in(ctx, cpuctx, event_type);
+}
+
+static void task_ctx_sched_in(struct task_struct *task,
+ enum event_type_t event_type)
+{
+ struct perf_cpu_context *cpuctx = &__get_cpu_var(perf_cpu_context);
+ struct perf_event_context *ctx = task->perf_event_ctxp;
+
+ if (likely(!ctx))
+ return;
+ if (cpuctx->task_ctx == ctx)
+ return;
+ ctx_sched_in(ctx, cpuctx, event_type);
+ cpuctx->task_ctx = ctx;
+}
+/*
+ * Called from scheduler to add the events of the current task
+ * with interrupts disabled.
+ *
+ * We restore the event value and then enable it.
+ *
+ * This does not protect us against NMI, but enable()
+ * sets the enabled bit in the control field of event _before_
+ * accessing the event control register. If a NMI hits, then it will
+ * keep the event running.
+ */
+void perf_event_task_sched_in(struct task_struct *task)
+{
+ struct perf_cpu_context *cpuctx = &__get_cpu_var(perf_cpu_context);
+ struct perf_event_context *ctx = task->perf_event_ctxp;
+
+ if (likely(!ctx))
+ return;
+
+ if (cpuctx->task_ctx == ctx)
+ return;
+
+ perf_disable();
+
+ /*
+ * We want to keep the following priority order:
+ * cpu pinned (that don't need to move), task pinned,
+ * cpu flexible, task flexible.
+ */
+ cpu_ctx_sched_out(cpuctx, EVENT_FLEXIBLE);
+
+ ctx_sched_in(ctx, cpuctx, EVENT_PINNED);
+ cpu_ctx_sched_in(cpuctx, EVENT_FLEXIBLE);
+ ctx_sched_in(ctx, cpuctx, EVENT_FLEXIBLE);
+
+ cpuctx->task_ctx = ctx;
+
+ perf_enable();
+}
+
+#define MAX_INTERRUPTS (~0ULL)
+
+static void perf_log_throttle(struct perf_event *event, int enable);
+
+static u64 perf_calculate_period(struct perf_event *event, u64 nsec, u64 count)
+{
+ u64 frequency = event->attr.sample_freq;
+ u64 sec = NSEC_PER_SEC;
+ u64 divisor, dividend;
+
+ int count_fls, nsec_fls, frequency_fls, sec_fls;
+
+ count_fls = fls64(count);
+ nsec_fls = fls64(nsec);
+ frequency_fls = fls64(frequency);
+ sec_fls = 30;
+
+ /*
+ * We got @count in @nsec, with a target of sample_freq HZ
+ * the target period becomes:
+ *
+ * @count * 10^9
+ * period = -------------------
+ * @nsec * sample_freq
+ *
+ */
+
+ /*
+ * Reduce accuracy by one bit such that @a and @b converge
+ * to a similar magnitude.
+ */
+#define REDUCE_FLS(a, b) \
+do { \
+ if (a##_fls > b##_fls) { \
+ a >>= 1; \
+ a##_fls--; \
+ } else { \
+ b >>= 1; \
+ b##_fls--; \
+ } \
+} while (0)
+
+ /*
+ * Reduce accuracy until either term fits in a u64, then proceed with
+ * the other, so that finally we can do a u64/u64 division.
+ */
+ while (count_fls + sec_fls > 64 && nsec_fls + frequency_fls > 64) {
+ REDUCE_FLS(nsec, frequency);
+ REDUCE_FLS(sec, count);
+ }
+
+ if (count_fls + sec_fls > 64) {
+ divisor = nsec * frequency;
+
+ while (count_fls + sec_fls > 64) {
+ REDUCE_FLS(count, sec);
+ divisor >>= 1;
+ }
+
+ dividend = count * sec;
+ } else {
+ dividend = count * sec;
+
+ while (nsec_fls + frequency_fls > 64) {
+ REDUCE_FLS(nsec, frequency);
+ dividend >>= 1;
+ }
+
+ divisor = nsec * frequency;
+ }
+
+ if (!divisor)
+ return dividend;
+
+ return div64_u64(dividend, divisor);
+}
+
+static void perf_event_stop(struct perf_event *event)
+{
+ if (!event->pmu->stop)
+ return event->pmu->disable(event);
+
+ return event->pmu->stop(event);
+}
+
+static int perf_event_start(struct perf_event *event)
+{
+ if (!event->pmu->start)
+ return event->pmu->enable(event);
+
+ return event->pmu->start(event);
+}
+
+static void perf_adjust_period(struct perf_event *event, u64 nsec, u64 count)
+{
+ struct hw_perf_event *hwc = &event->hw;
+ s64 period, sample_period;
+ s64 delta;
+
+ period = perf_calculate_period(event, nsec, count);
+
+ delta = (s64)(period - hwc->sample_period);
+ delta = (delta + 7) / 8; /* low pass filter */
+
+ sample_period = hwc->sample_period + delta;
+
+ if (!sample_period)
+ sample_period = 1;
+
+ hwc->sample_period = sample_period;
+
+ if (local64_read(&hwc->period_left) > 8*sample_period) {
+ perf_disable();
+ perf_event_stop(event);
+ local64_set(&hwc->period_left, 0);
+ perf_event_start(event);
+ perf_enable();
+ }
+}
+
+static void perf_ctx_adjust_freq(struct perf_event_context *ctx)
+{
+ struct perf_event *event;
+ struct hw_perf_event *hwc;
+ u64 interrupts, now;
+ s64 delta;
+
+ raw_spin_lock(&ctx->lock);
+ list_for_each_entry_rcu(event, &ctx->event_list, event_entry) {
+ if (event->state != PERF_EVENT_STATE_ACTIVE)
+ continue;
+
+ if (event->cpu != -1 && event->cpu != smp_processor_id())
+ continue;
+
+ hwc = &event->hw;
+
+ interrupts = hwc->interrupts;
+ hwc->interrupts = 0;
+
+ /*
+ * unthrottle events on the tick
+ */
+ if (interrupts == MAX_INTERRUPTS) {
+ perf_log_throttle(event, 1);
+ perf_disable();
+ event->pmu->unthrottle(event);
+ perf_enable();
+ }
+
+ if (!event->attr.freq || !event->attr.sample_freq)
+ continue;
+
+ perf_disable();
+ event->pmu->read(event);
+ now = local64_read(&event->count);
+ delta = now - hwc->freq_count_stamp;
+ hwc->freq_count_stamp = now;
+
+ if (delta > 0)
+ perf_adjust_period(event, TICK_NSEC, delta);
+ perf_enable();
+ }
+ raw_spin_unlock(&ctx->lock);
+}
+
+/*
+ * Round-robin a context's events:
+ */
+static void rotate_ctx(struct perf_event_context *ctx)
+{
+ raw_spin_lock(&ctx->lock);
+
+ /* Rotate the first entry last of non-pinned groups */
+ list_rotate_left(&ctx->flexible_groups);
+
+ raw_spin_unlock(&ctx->lock);
+}
+
+void perf_event_task_tick(struct task_struct *curr)
+{
+ struct perf_cpu_context *cpuctx;
+ struct perf_event_context *ctx;
+ int rotate = 0;
+
+ if (!atomic_read(&nr_events))
+ return;
+
+ cpuctx = &__get_cpu_var(perf_cpu_context);
+ if (cpuctx->ctx.nr_events &&
+ cpuctx->ctx.nr_events != cpuctx->ctx.nr_active)
+ rotate = 1;
+
+ ctx = curr->perf_event_ctxp;
+ if (ctx && ctx->nr_events && ctx->nr_events != ctx->nr_active)
+ rotate = 1;
+
+ perf_ctx_adjust_freq(&cpuctx->ctx);
+ if (ctx)
+ perf_ctx_adjust_freq(ctx);
+
+ if (!rotate)
+ return;
+
+ perf_disable();
+ cpu_ctx_sched_out(cpuctx, EVENT_FLEXIBLE);
+ if (ctx)
+ task_ctx_sched_out(ctx, EVENT_FLEXIBLE);
+
+ rotate_ctx(&cpuctx->ctx);
+ if (ctx)
+ rotate_ctx(ctx);
+
+ cpu_ctx_sched_in(cpuctx, EVENT_FLEXIBLE);
+ if (ctx)
+ task_ctx_sched_in(curr, EVENT_FLEXIBLE);
+ perf_enable();
+}
+
+static int event_enable_on_exec(struct perf_event *event,
+ struct perf_event_context *ctx)
+{
+ if (!event->attr.enable_on_exec)
+ return 0;
+
+ event->attr.enable_on_exec = 0;
+ if (event->state >= PERF_EVENT_STATE_INACTIVE)
+ return 0;
+
+ __perf_event_mark_enabled(event, ctx);
+
+ return 1;
+}
+
+/*
+ * Enable all of a task's events that have been marked enable-on-exec.
+ * This expects task == current.
+ */
+static void perf_event_enable_on_exec(struct task_struct *task)
+{
+ struct perf_event_context *ctx;
+ struct perf_event *event;
+ unsigned long flags;
+ int enabled = 0;
+ int ret;
+
+ local_irq_save(flags);
+ ctx = task->perf_event_ctxp;
+ if (!ctx || !ctx->nr_events)
+ goto out;
+
+ __perf_event_task_sched_out(ctx);
+
+ raw_spin_lock(&ctx->lock);
+
+ list_for_each_entry(event, &ctx->pinned_groups, group_entry) {
+ ret = event_enable_on_exec(event, ctx);
+ if (ret)
+ enabled = 1;
+ }
+
+ list_for_each_entry(event, &ctx->flexible_groups, group_entry) {
+ ret = event_enable_on_exec(event, ctx);
+ if (ret)
+ enabled = 1;
+ }
+
+ /*
+ * Unclone this context if we enabled any event.
+ */
+ if (enabled)
+ unclone_ctx(ctx);
+
+ raw_spin_unlock(&ctx->lock);
+
+ perf_event_task_sched_in(task);
+ out:
+ local_irq_restore(flags);
+}
+
+/*
+ * Cross CPU call to read the hardware event
+ */
+static void __perf_event_read(void *info)
+{
+ struct perf_cpu_context *cpuctx = &__get_cpu_var(perf_cpu_context);
+ struct perf_event *event = info;
+ struct perf_event_context *ctx = event->ctx;
+
+ /*
+ * If this is a task context, we need to check whether it is
+ * the current task context of this cpu. If not it has been
+ * scheduled out before the smp call arrived. In that case
+ * event->count would have been updated to a recent sample
+ * when the event was scheduled out.
+ */
+ if (ctx->task && cpuctx->task_ctx != ctx)
+ return;
+
+ raw_spin_lock(&ctx->lock);
+ update_context_time(ctx);
+ update_event_times(event);
+ raw_spin_unlock(&ctx->lock);
+
+ event->pmu->read(event);
+}
+
+static inline u64 perf_event_count(struct perf_event *event)
+{
+ return local64_read(&event->count) + atomic64_read(&event->child_count);
+}
+
+static u64 perf_event_read(struct perf_event *event)
+{
+ /*
+ * If event is enabled and currently active on a CPU, update the
+ * value in the event structure:
+ */
+ if (event->state == PERF_EVENT_STATE_ACTIVE) {
+ smp_call_function_single(event->oncpu,
+ __perf_event_read, event, 1);
+ } else if (event->state == PERF_EVENT_STATE_INACTIVE) {
+ struct perf_event_context *ctx = event->ctx;
+ unsigned long flags;
+
+ raw_spin_lock_irqsave(&ctx->lock, flags);
+ update_context_time(ctx);
+ update_event_times(event);
+ raw_spin_unlock_irqrestore(&ctx->lock, flags);
+ }
+
+ return perf_event_count(event);
+}
+
+/*
+ * Initialize the perf_event context in a task_struct:
+ */
+static void
+__perf_event_init_context(struct perf_event_context *ctx,
+ struct task_struct *task)
+{
+ raw_spin_lock_init(&ctx->lock);
+ mutex_init(&ctx->mutex);
+ INIT_LIST_HEAD(&ctx->pinned_groups);
+ INIT_LIST_HEAD(&ctx->flexible_groups);
+ INIT_LIST_HEAD(&ctx->event_list);
+ atomic_set(&ctx->refcount, 1);
+ ctx->task = task;
+}
+
+static struct perf_event_context *find_get_context(pid_t pid, int cpu)
+{
+ struct perf_event_context *ctx;
+ struct perf_cpu_context *cpuctx;
+ struct task_struct *task;
+ unsigned long flags;
+ int err;
+
+ if (pid == -1 && cpu != -1) {
+ /* Must be root to operate on a CPU event: */
+ if (perf_paranoid_cpu() && !capable(CAP_SYS_ADMIN))
+ return ERR_PTR(-EACCES);
+
+ if (cpu < 0 || cpu >= nr_cpumask_bits)
+ return ERR_PTR(-EINVAL);
+
+ /*
+ * We could be clever and allow to attach a event to an
+ * offline CPU and activate it when the CPU comes up, but
+ * that's for later.
+ */
+ if (!cpu_online(cpu))
+ return ERR_PTR(-ENODEV);
+
+ cpuctx = &per_cpu(perf_cpu_context, cpu);
+ ctx = &cpuctx->ctx;
+ get_ctx(ctx);
+
+ return ctx;
+ }
+
+ rcu_read_lock();
+ if (!pid)
+ task = current;
+ else
+ task = find_task_by_vpid(pid);
+ if (task)
+ get_task_struct(task);
+ rcu_read_unlock();
+
+ if (!task)
+ return ERR_PTR(-ESRCH);
+
+ /*
+ * Can't attach events to a dying task.
+ */
+ err = -ESRCH;
+ if (task->flags & PF_EXITING)
+ goto errout;
+
+ /* Reuse ptrace permission checks for now. */
+ err = -EACCES;
+ if (!ptrace_may_access(task, PTRACE_MODE_READ))
+ goto errout;
+
+ retry:
+ ctx = perf_lock_task_context(task, &flags);
+ if (ctx) {
+ unclone_ctx(ctx);
+ raw_spin_unlock_irqrestore(&ctx->lock, flags);
+ }
+
+ if (!ctx) {
+ ctx = kzalloc(sizeof(struct perf_event_context), GFP_KERNEL);
+ err = -ENOMEM;
+ if (!ctx)
+ goto errout;
+ __perf_event_init_context(ctx, task);
+ get_ctx(ctx);
+ if (cmpxchg(&task->perf_event_ctxp, NULL, ctx)) {
+ /*
+ * We raced with some other task; use
+ * the context they set.
+ */
+ kfree(ctx);
+ goto retry;
+ }
+ get_task_struct(task);
+ }
+
+ put_task_struct(task);
+ return ctx;
+
+ errout:
+ put_task_struct(task);
+ return ERR_PTR(err);
+}
+
+static void perf_event_free_filter(struct perf_event *event);
+
+static void free_event_rcu(struct rcu_head *head)
+{
+ struct perf_event *event;
+
+ event = container_of(head, struct perf_event, rcu_head);
+ if (event->ns)
+ put_pid_ns(event->ns);
+ perf_event_free_filter(event);
+ kfree(event);
+}
+
+static void perf_pending_sync(struct perf_event *event);
+static void perf_buffer_put(struct perf_buffer *buffer);
+
+static void free_event(struct perf_event *event)
+{
+ perf_pending_sync(event);
+
+ if (!event->parent) {
+ atomic_dec(&nr_events);
+ if (event->attr.mmap || event->attr.mmap_data)
+ atomic_dec(&nr_mmap_events);
+ if (event->attr.comm)
+ atomic_dec(&nr_comm_events);
+ if (event->attr.task)
+ atomic_dec(&nr_task_events);
+ }
+
+ if (event->buffer) {
+ perf_buffer_put(event->buffer);
+ event->buffer = NULL;
+ }
+
+ if (event->destroy)
+ event->destroy(event);
+
+ put_ctx(event->ctx);
+ call_rcu(&event->rcu_head, free_event_rcu);
+}
+
+int perf_event_release_kernel(struct perf_event *event)
+{
+ struct perf_event_context *ctx = event->ctx;
+
+ /*
+ * Remove from the PMU, can't get re-enabled since we got
+ * here because the last ref went.
+ */
+ perf_event_disable(event);
+
+ WARN_ON_ONCE(ctx->parent_ctx);
+ /*
+ * There are two ways this annotation is useful:
+ *
+ * 1) there is a lock recursion from perf_event_exit_task
+ * see the comment there.
+ *
+ * 2) there is a lock-inversion with mmap_sem through
+ * perf_event_read_group(), which takes faults while
+ * holding ctx->mutex, however this is called after
+ * the last filedesc died, so there is no possibility
+ * to trigger the AB-BA case.
+ */
+ mutex_lock_nested(&ctx->mutex, SINGLE_DEPTH_NESTING);
+ raw_spin_lock_irq(&ctx->lock);
+ perf_group_detach(event);
+ list_del_event(event, ctx);
+ raw_spin_unlock_irq(&ctx->lock);
+ mutex_unlock(&ctx->mutex);
+
+ mutex_lock(&event->owner->perf_event_mutex);
+ list_del_init(&event->owner_entry);
+ mutex_unlock(&event->owner->perf_event_mutex);
+ put_task_struct(event->owner);
+
+ free_event(event);
+
+ return 0;
+}
+EXPORT_SYMBOL_GPL(perf_event_release_kernel);
+
+/*
+ * Called when the last reference to the file is gone.
+ */
+static int perf_release(struct inode *inode, struct file *file)
+{
+ struct perf_event *event = file->private_data;
+
+ file->private_data = NULL;
+
+ return perf_event_release_kernel(event);
+}
+
+static int perf_event_read_size(struct perf_event *event)
+{
+ int entry = sizeof(u64); /* value */
+ int size = 0;
+ int nr = 1;
+
+ if (event->attr.read_format & PERF_FORMAT_TOTAL_TIME_ENABLED)
+ size += sizeof(u64);
+
+ if (event->attr.read_format & PERF_FORMAT_TOTAL_TIME_RUNNING)
+ size += sizeof(u64);
+
+ if (event->attr.read_format & PERF_FORMAT_ID)
+ entry += sizeof(u64);
+
+ if (event->attr.read_format & PERF_FORMAT_GROUP) {
+ nr += event->group_leader->nr_siblings;
+ size += sizeof(u64);
+ }
+
+ size += entry * nr;
+
+ return size;
+}
+
+u64 perf_event_read_value(struct perf_event *event, u64 *enabled, u64 *running)
+{
+ struct perf_event *child;
+ u64 total = 0;
+
+ *enabled = 0;
+ *running = 0;
+
+ mutex_lock(&event->child_mutex);
+ total += perf_event_read(event);
+ *enabled += event->total_time_enabled +
+ atomic64_read(&event->child_total_time_enabled);
+ *running += event->total_time_running +
+ atomic64_read(&event->child_total_time_running);
+
+ list_for_each_entry(child, &event->child_list, child_list) {
+ total += perf_event_read(child);
+ *enabled += child->total_time_enabled;
+ *running += child->total_time_running;
+ }
+ mutex_unlock(&event->child_mutex);
+
+ return total;
+}
+EXPORT_SYMBOL_GPL(perf_event_read_value);
+
+static int perf_event_read_group(struct perf_event *event,
+ u64 read_format, char __user *buf)
+{
+ struct perf_event *leader = event->group_leader, *sub;
+ int n = 0, size = 0, ret = -EFAULT;
+ struct perf_event_context *ctx = leader->ctx;
+ u64 values[5];
+ u64 count, enabled, running;
+
+ mutex_lock(&ctx->mutex);
+ count = perf_event_read_value(leader, &enabled, &running);
+
+ values[n++] = 1 + leader->nr_siblings;
+ if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED)
+ values[n++] = enabled;
+ if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING)
+ values[n++] = running;
+ values[n++] = count;
+ if (read_format & PERF_FORMAT_ID)
+ values[n++] = primary_event_id(leader);
+
+ size = n * sizeof(u64);
+
+ if (copy_to_user(buf, values, size))
+ goto unlock;
+
+ ret = size;
+
+ list_for_each_entry(sub, &leader->sibling_list, group_entry) {
+ n = 0;
+
+ values[n++] = perf_event_read_value(sub, &enabled, &running);
+ if (read_format & PERF_FORMAT_ID)
+ values[n++] = primary_event_id(sub);
+
+ size = n * sizeof(u64);
+
+ if (copy_to_user(buf + ret, values, size)) {
+ ret = -EFAULT;
+ goto unlock;
+ }
+
+ ret += size;
+ }
+unlock:
+ mutex_unlock(&ctx->mutex);
+
+ return ret;
+}
+
+static int perf_event_read_one(struct perf_event *event,
+ u64 read_format, char __user *buf)
+{
+ u64 enabled, running;
+ u64 values[4];
+ int n = 0;
+
+ values[n++] = perf_event_read_value(event, &enabled, &running);
+ if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED)
+ values[n++] = enabled;
+ if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING)
+ values[n++] = running;
+ if (read_format & PERF_FORMAT_ID)
+ values[n++] = primary_event_id(event);
+
+ if (copy_to_user(buf, values, n * sizeof(u64)))
+ return -EFAULT;
+
+ return n * sizeof(u64);
+}
+
+/*
+ * Read the performance event - simple non blocking version for now
+ */
+static ssize_t
+perf_read_hw(struct perf_event *event, char __user *buf, size_t count)
+{
+ u64 read_format = event->attr.read_format;
+ int ret;
+
+ /*
+ * Return end-of-file for a read on a event that is in
+ * error state (i.e. because it was pinned but it couldn't be
+ * scheduled on to the CPU at some point).
+ */
+ if (event->state == PERF_EVENT_STATE_ERROR)
+ return 0;
+
+ if (count < perf_event_read_size(event))
+ return -ENOSPC;
+
+ WARN_ON_ONCE(event->ctx->parent_ctx);
+ if (read_format & PERF_FORMAT_GROUP)
+ ret = perf_event_read_group(event, read_format, buf);
+ else
+ ret = perf_event_read_one(event, read_format, buf);
+
+ return ret;
+}
+
+static ssize_t
+perf_read(struct file *file, char __user *buf, size_t count, loff_t *ppos)
+{
+ struct perf_event *event = file->private_data;
+
+ return perf_read_hw(event, buf, count);
+}
+
+static unsigned int perf_poll(struct file *file, poll_table *wait)
+{
+ struct perf_event *event = file->private_data;
+ struct perf_buffer *buffer;
+ unsigned int events = POLL_HUP;
+
+ rcu_read_lock();
+ buffer = rcu_dereference(event->buffer);
+ if (buffer)
+ events = atomic_xchg(&buffer->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);
+ local64_set(&event->count, 0);
+ perf_event_update_userpage(event);
+}
+
+/*
+ * Holding the top-level event's child_mutex means that any
+ * descendant process that has inherited this event will block
+ * in sync_child_event if it goes to exit, thus satisfying the
+ * task existence requirements of perf_event_enable/disable.
+ */
+static void perf_event_for_each_child(struct perf_event *event,
+ void (*func)(struct perf_event *))
+{
+ struct perf_event *child;
+
+ WARN_ON_ONCE(event->ctx->parent_ctx);
+ mutex_lock(&event->child_mutex);
+ func(event);
+ list_for_each_entry(child, &event->child_list, child_list)
+ func(child);
+ mutex_unlock(&event->child_mutex);
+}
+
+static void perf_event_for_each(struct perf_event *event,
+ void (*func)(struct perf_event *))
+{
+ struct perf_event_context *ctx = event->ctx;
+ struct perf_event *sibling;
+
+ WARN_ON_ONCE(ctx->parent_ctx);
+ mutex_lock(&ctx->mutex);
+ event = event->group_leader;
+
+ perf_event_for_each_child(event, func);
+ 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;
+ int ret = 0;
+ u64 value;
+
+ if (!event->attr.sample_period)
+ return -EINVAL;
+
+ if (copy_from_user(&value, arg, sizeof(value)))
+ return -EFAULT;
+
+ if (!value)
+ return -EINVAL;
+
+ raw_spin_lock_irq(&ctx->lock);
+ if (event->attr.freq) {
+ if (value > sysctl_perf_event_sample_rate) {
+ ret = -EINVAL;
+ goto unlock;
+ }
+
+ event->attr.sample_freq = value;
+ } else {
+ event->attr.sample_period = value;
+ event->hw.sample_period = value;
+ }
+unlock:
+ raw_spin_unlock_irq(&ctx->lock);
+
+ return ret;
+}
+
+static const struct file_operations perf_fops;
+
+static struct perf_event *perf_fget_light(int fd, int *fput_needed)
+{
+ struct file *file;
+
+ file = fget_light(fd, fput_needed);
+ if (!file)
+ return ERR_PTR(-EBADF);
+
+ if (file->f_op != &perf_fops) {
+ fput_light(file, *fput_needed);
+ *fput_needed = 0;
+ return ERR_PTR(-EBADF);
+ }
+
+ return file->private_data;
+}
+
+static int perf_event_set_output(struct perf_event *event,
+ struct perf_event *output_event);
+static int perf_event_set_filter(struct perf_event *event, void __user *arg);
+
+static long perf_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
+{
+ struct perf_event *event = file->private_data;
+ void (*func)(struct perf_event *);
+ u32 flags = arg;
+
+ switch (cmd) {
+ case PERF_EVENT_IOC_ENABLE:
+ func = perf_event_enable;
+ break;
+ case PERF_EVENT_IOC_DISABLE:
+ func = perf_event_disable;
+ break;
+ case PERF_EVENT_IOC_RESET:
+ func = perf_event_reset;
+ break;
+
+ case PERF_EVENT_IOC_REFRESH:
+ return perf_event_refresh(event, arg);
+
+ case PERF_EVENT_IOC_PERIOD:
+ return perf_event_period(event, (u64 __user *)arg);
+
+ case PERF_EVENT_IOC_SET_OUTPUT:
+ {
+ struct perf_event *output_event = NULL;
+ int fput_needed = 0;
+ int ret;
+
+ if (arg != -1) {
+ output_event = perf_fget_light(arg, &fput_needed);
+ if (IS_ERR(output_event))
+ return PTR_ERR(output_event);
+ }
+
+ ret = perf_event_set_output(event, output_event);
+ if (output_event)
+ fput_light(output_event->filp, fput_needed);
+
+ return ret;
+ }
+
+ case PERF_EVENT_IOC_SET_FILTER:
+ return perf_event_set_filter(event, (void __user *)arg);
+
+ default:
+ return -ENOTTY;
+ }
+
+ if (flags & PERF_IOC_FLAG_GROUP)
+ perf_event_for_each(event, func);
+ else
+ perf_event_for_each_child(event, func);
+
+ return 0;
+}
+
+int perf_event_task_enable(void)
+{
+ struct perf_event *event;
+
+ mutex_lock(&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_buffer *buffer;
+
+ rcu_read_lock();
+ buffer = rcu_dereference(event->buffer);
+ if (!buffer)
+ goto unlock;
+
+ userpg = buffer->user_page;
+
+ /*
+ * Disable preemption so as to not let the corresponding user-space
+ * spin too long if we get preempted.
+ */
+ preempt_disable();
+ ++userpg->lock;
+ barrier();
+ userpg->index = perf_event_index(event);
+ userpg->offset = perf_event_count(event);
+ if (event->state == PERF_EVENT_STATE_ACTIVE)
+ userpg->offset -= local64_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 unsigned long perf_data_size(struct perf_buffer *buffer);
+
+static void
+perf_buffer_init(struct perf_buffer *buffer, long watermark, int flags)
+{
+ long max_size = perf_data_size(buffer);
+
+ if (watermark)
+ buffer->watermark = min(max_size, watermark);
+
+ if (!buffer->watermark)
+ buffer->watermark = max_size / 2;
+
+ if (flags & PERF_BUFFER_WRITABLE)
+ buffer->writable = 1;
+
+ atomic_set(&buffer->refcount, 1);
+}
+
+#ifndef CONFIG_PERF_USE_VMALLOC
+
+/*
+ * Back perf_mmap() with regular GFP_KERNEL-0 pages.
+ */
+
+static struct page *
+perf_mmap_to_page(struct perf_buffer *buffer, unsigned long pgoff)
+{
+ if (pgoff > buffer->nr_pages)
+ return NULL;
+
+ if (pgoff == 0)
+ return virt_to_page(buffer->user_page);
+
+ return virt_to_page(buffer->data_pages[pgoff - 1]);
+}
+
+static void *perf_mmap_alloc_page(int cpu)
+{
+ struct page *page;
+ int node;
+
+ node = (cpu == -1) ? cpu : cpu_to_node(cpu);
+ page = alloc_pages_node(node, GFP_KERNEL | __GFP_ZERO, 0);
+ if (!page)
+ return NULL;
+
+ return page_address(page);
+}
+
+static struct perf_buffer *
+perf_buffer_alloc(int nr_pages, long watermark, int cpu, int flags)
+{
+ struct perf_buffer *buffer;
+ unsigned long size;
+ int i;
+
+ size = sizeof(struct perf_buffer);
+ size += nr_pages * sizeof(void *);
+
+ buffer = kzalloc(size, GFP_KERNEL);
+ if (!buffer)
+ goto fail;
+
+ buffer->user_page = perf_mmap_alloc_page(cpu);
+ if (!buffer->user_page)
+ goto fail_user_page;
+
+ for (i = 0; i < nr_pages; i++) {
+ buffer->data_pages[i] = perf_mmap_alloc_page(cpu);
+ if (!buffer->data_pages[i])
+ goto fail_data_pages;
+ }
+
+ buffer->nr_pages = nr_pages;
+
+ perf_buffer_init(buffer, watermark, flags);
+
+ return buffer;
+
+fail_data_pages:
+ for (i--; i >= 0; i--)
+ free_page((unsigned long)buffer->data_pages[i]);
+
+ free_page((unsigned long)buffer->user_page);
+
+fail_user_page:
+ kfree(buffer);
+
+fail:
+ return NULL;
+}
+
+static void perf_mmap_free_page(unsigned long addr)
+{
+ struct page *page = virt_to_page((void *)addr);
+
+ page->mapping = NULL;
+ __free_page(page);
+}
+
+static void perf_buffer_free(struct perf_buffer *buffer)
+{
+ int i;
+
+ perf_mmap_free_page((unsigned long)buffer->user_page);
+ for (i = 0; i < buffer->nr_pages; i++)
+ perf_mmap_free_page((unsigned long)buffer->data_pages[i]);
+ kfree(buffer);
+}
+
+static inline int page_order(struct perf_buffer *buffer)
+{
+ return 0;
+}
+
+#else
+
+/*
+ * Back perf_mmap() with vmalloc memory.
+ *
+ * Required for architectures that have d-cache aliasing issues.
+ */
+
+static inline int page_order(struct perf_buffer *buffer)
+{
+ return buffer->page_order;
+}
+
+static struct page *
+perf_mmap_to_page(struct perf_buffer *buffer, unsigned long pgoff)
+{
+ if (pgoff > (1UL << page_order(buffer)))
+ return NULL;
+
+ return vmalloc_to_page((void *)buffer->user_page + pgoff * PAGE_SIZE);
+}
+
+static void perf_mmap_unmark_page(void *addr)
+{
+ struct page *page = vmalloc_to_page(addr);
+
+ page->mapping = NULL;
+}
+
+static void perf_buffer_free_work(struct work_struct *work)
+{
+ struct perf_buffer *buffer;
+ void *base;
+ int i, nr;
+
+ buffer = container_of(work, struct perf_buffer, work);
+ nr = 1 << page_order(buffer);
+
+ base = buffer->user_page;
+ for (i = 0; i < nr + 1; i++)
+ perf_mmap_unmark_page(base + (i * PAGE_SIZE));
+
+ vfree(base);
+ kfree(buffer);
+}
+
+static void perf_buffer_free(struct perf_buffer *buffer)
+{
+ schedule_work(&buffer->work);
+}
+
+static struct perf_buffer *
+perf_buffer_alloc(int nr_pages, long watermark, int cpu, int flags)
+{
+ struct perf_buffer *buffer;
+ unsigned long size;
+ void *all_buf;
+
+ size = sizeof(struct perf_buffer);
+ size += sizeof(void *);
+
+ buffer = kzalloc(size, GFP_KERNEL);
+ if (!buffer)
+ goto fail;
+
+ INIT_WORK(&buffer->work, perf_buffer_free_work);
+
+ all_buf = vmalloc_user((nr_pages + 1) * PAGE_SIZE);
+ if (!all_buf)
+ goto fail_all_buf;
+
+ buffer->user_page = all_buf;
+ buffer->data_pages[0] = all_buf + PAGE_SIZE;
+ buffer->page_order = ilog2(nr_pages);
+ buffer->nr_pages = 1;
+
+ perf_buffer_init(buffer, watermark, flags);
+
+ return buffer;
+
+fail_all_buf:
+ kfree(buffer);
+
+fail:
+ return NULL;
+}
+
+#endif
+
+static unsigned long perf_data_size(struct perf_buffer *buffer)
+{
+ return buffer->nr_pages << (PAGE_SHIFT + page_order(buffer));
+}
+
+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_buffer *buffer;
+ int ret = VM_FAULT_SIGBUS;
+
+ if (vmf->flags & FAULT_FLAG_MKWRITE) {
+ if (vmf->pgoff == 0)
+ ret = 0;
+ return ret;
+ }
+
+ rcu_read_lock();
+ buffer = rcu_dereference(event->buffer);
+ if (!buffer)
+ goto unlock;
+
+ if (vmf->pgoff && (vmf->flags & FAULT_FLAG_WRITE))
+ goto unlock;
+
+ vmf->page = perf_mmap_to_page(buffer, vmf->pgoff);
+ if (!vmf->page)
+ goto unlock;
+
+ get_page(vmf->page);
+ vmf->page->mapping = vma->vm_file->f_mapping;
+ vmf->page->index = vmf->pgoff;
+
+ ret = 0;
+unlock:
+ rcu_read_unlock();
+
+ return ret;
+}
+
+static void perf_buffer_free_rcu(struct rcu_head *rcu_head)
+{
+ struct perf_buffer *buffer;
+
+ buffer = container_of(rcu_head, struct perf_buffer, rcu_head);
+ perf_buffer_free(buffer);
+}
+
+static struct perf_buffer *perf_buffer_get(struct perf_event *event)
+{
+ struct perf_buffer *buffer;
+
+ rcu_read_lock();
+ buffer = rcu_dereference(event->buffer);
+ if (buffer) {
+ if (!atomic_inc_not_zero(&buffer->refcount))
+ buffer = NULL;
+ }
+ rcu_read_unlock();
+
+ return buffer;
+}
+
+static void perf_buffer_put(struct perf_buffer *buffer)
+{
+ if (!atomic_dec_and_test(&buffer->refcount))
+ return;
+
+ call_rcu(&buffer->rcu_head, perf_buffer_free_rcu);
+}
+
+static void perf_mmap_open(struct vm_area_struct *vma)
+{
+ struct perf_event *event = vma->vm_file->private_data;
+
+ atomic_inc(&event->mmap_count);
+}
+
+static void perf_mmap_close(struct vm_area_struct *vma)
+{
+ struct perf_event *event = vma->vm_file->private_data;
+
+ if (atomic_dec_and_mutex_lock(&event->mmap_count, &event->mmap_mutex)) {
+ unsigned long size = perf_data_size(event->buffer);
+ struct user_struct *user = event->mmap_user;
+ struct perf_buffer *buffer = event->buffer;
+
+ atomic_long_sub((size >> PAGE_SHIFT) + 1, &user->locked_vm);
+ vma->vm_mm->locked_vm -= event->mmap_locked;
+ rcu_assign_pointer(event->buffer, NULL);
+ mutex_unlock(&event->mmap_mutex);
+
+ perf_buffer_put(buffer);
+ free_uid(user);
+ }
+}
+
+static const struct vm_operations_struct perf_mmap_vmops = {
+ .open = perf_mmap_open,
+ .close = perf_mmap_close,
+ .fault = perf_mmap_fault,
+ .page_mkwrite = perf_mmap_fault,
+};
+
+static int perf_mmap(struct file *file, struct vm_area_struct *vma)
+{
+ struct perf_event *event = file->private_data;
+ unsigned long user_locked, user_lock_limit;
+ struct user_struct *user = current_user();
+ unsigned long locked, lock_limit;
+ struct perf_buffer *buffer;
+ unsigned long vma_size;
+ unsigned long nr_pages;
+ long user_extra, extra;
+ int ret = 0, flags = 0;
+
+ /*
+ * Don't allow mmap() of inherited per-task counters. This would
+ * create a performance issue due to all children writing to the
+ * same buffer.
+ */
+ if (event->cpu == -1 && event->attr.inherit)
+ return -EINVAL;
+
+ if (!(vma->vm_flags & VM_SHARED))
+ return -EINVAL;
+
+ vma_size = vma->vm_end - vma->vm_start;
+ nr_pages = (vma_size / PAGE_SIZE) - 1;
+
+ /*
+ * If we have buffer 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->buffer) {
+ if (event->buffer->nr_pages == nr_pages)
+ atomic_inc(&event->buffer->refcount);
+ else
+ ret = -EINVAL;
+ goto unlock;
+ }
+
+ user_extra = nr_pages + 1;
+ user_lock_limit = sysctl_perf_event_mlock >> (PAGE_SHIFT - 10);
+
+ /*
+ * Increase the limit linearly with more CPUs:
+ */
+ user_lock_limit *= num_online_cpus();
+
+ user_locked = atomic_long_read(&user->locked_vm) + user_extra;
+
+ extra = 0;
+ if (user_locked > user_lock_limit)
+ extra = user_locked - user_lock_limit;
+
+ lock_limit = rlimit(RLIMIT_MEMLOCK);
+ lock_limit >>= PAGE_SHIFT;
+ locked = vma->vm_mm->locked_vm + extra;
+
+ if ((locked > lock_limit) && perf_paranoid_tracepoint_raw() &&
+ !capable(CAP_IPC_LOCK)) {
+ ret = -EPERM;
+ goto unlock;
+ }
+
+ WARN_ON(event->buffer);
+
+ if (vma->vm_flags & VM_WRITE)
+ flags |= PERF_BUFFER_WRITABLE;
+
+ buffer = perf_buffer_alloc(nr_pages, event->attr.wakeup_watermark,
+ event->cpu, flags);
+ if (!buffer) {
+ ret = -ENOMEM;
+ goto unlock;
+ }
+ rcu_assign_pointer(event->buffer, buffer);
+
+ atomic_long_add(user_extra, &user->locked_vm);
+ event->mmap_locked = extra;
+ event->mmap_user = get_current_user();
+ vma->vm_mm->locked_vm += event->mmap_locked;
+
+unlock:
+ if (!ret)
+ atomic_inc(&event->mmap_count);
+ mutex_unlock(&event->mmap_mutex);
+
+ vma->vm_flags |= VM_RESERVED;
+ vma->vm_ops = &perf_mmap_vmops;
+
+ return ret;
+}
+
+static int perf_fasync(int fd, struct file *filp, int on)
+{
+ struct inode *inode = filp->f_path.dentry->d_inode;
+ struct perf_event *event = filp->private_data;
+ int retval;
+
+ mutex_lock(&inode->i_mutex);
+ retval = fasync_helper(fd, filp, on, &event->fasync);
+ mutex_unlock(&inode->i_mutex);
+
+ if (retval < 0)
+ return retval;
+
+ return 0;
+}
+
+static const struct file_operations perf_fops = {
+ .llseek = no_llseek,
+ .release = perf_release,
+ .read = perf_read,
+ .poll = perf_poll,
+ .unlocked_ioctl = perf_ioctl,
+ .compat_ioctl = perf_ioctl,
+ .mmap = perf_mmap,
+ .fasync = perf_fasync,
+};
+
+/*
+ * Perf event wakeup
+ *
+ * If there's data, ensure we set the poll() state and publish everything
+ * to user-space before waking everybody up.
+ */
+
+void perf_event_wakeup(struct perf_event *event)
+{
+ wake_up_all(&event->waitq);
+
+ if (event->pending_kill) {
+ kill_fasync(&event->fasync, SIGIO, event->pending_kill);
+ event->pending_kill = 0;
+ }
+}
+
+/*
+ * Pending wakeups
+ *
+ * Handle the case where we need to wakeup up from NMI (or rq->lock) context.
+ *
+ * The NMI bit means we cannot possibly take locks. Therefore, maintain a
+ * single linked list and use cmpxchg() to add entries lockless.
+ */
+
+static void perf_pending_event(struct perf_pending_entry *entry)
+{
+ struct perf_event *event = container_of(entry,
+ struct perf_event, pending);
+
+ if (event->pending_disable) {
+ event->pending_disable = 0;
+ __perf_event_disable(event);
+ }
+
+ if (event->pending_wakeup) {
+ event->pending_wakeup = 0;
+ perf_event_wakeup(event);
+ }
+}
+
+#define PENDING_TAIL ((struct perf_pending_entry *)-1UL)
+
+static DEFINE_PER_CPU(struct perf_pending_entry *, perf_pending_head) = {
+ PENDING_TAIL,
+};
+
+static void perf_pending_queue(struct perf_pending_entry *entry,
+ void (*func)(struct perf_pending_entry *))
+{
+ struct perf_pending_entry **head;
+
+ if (cmpxchg(&entry->next, NULL, PENDING_TAIL) != NULL)
+ return;
+
+ entry->func = func;
+
+ head = &get_cpu_var(perf_pending_head);
+
+ do {
+ entry->next = *head;
+ } while (cmpxchg(head, entry->next, entry) != entry->next);
+
+ set_perf_event_pending();
+
+ put_cpu_var(perf_pending_head);
+}
+
+static int __perf_pending_run(void)
+{
+ struct perf_pending_entry *list;
+ int nr = 0;
+
+ list = xchg(&__get_cpu_var(perf_pending_head), PENDING_TAIL);
+ while (list != PENDING_TAIL) {
+ void (*func)(struct perf_pending_entry *);
+ struct perf_pending_entry *entry = list;
+
+ list = list->next;
+
+ func = entry->func;
+ entry->next = NULL;
+ /*
+ * Ensure we observe the unqueue before we issue the wakeup,
+ * so that we won't be waiting forever.
+ * -- see perf_not_pending().
+ */
+ smp_wmb();
+
+ func(entry);
+ nr++;
+ }
+
+ return nr;
+}
+
+static inline int perf_not_pending(struct perf_event *event)
+{
+ /*
+ * If we flush on whatever cpu we run, there is a chance we don't
+ * need to wait.
+ */
+ get_cpu();
+ __perf_pending_run();
+ put_cpu();
+
+ /*
+ * Ensure we see the proper queue state before going to sleep
+ * so that we do not miss the wakeup. -- see perf_pending_handle()
+ */
+ smp_rmb();
+ return event->pending.next == NULL;
+}
+
+static void perf_pending_sync(struct perf_event *event)
+{
+ wait_event(event->waitq, perf_not_pending(event));
+}
+
+void perf_event_do_pending(void)
+{
+ __perf_pending_run();
+}
+
+/*
+ * Callchain support -- arch specific
+ */
+
+__weak struct perf_callchain_entry *perf_callchain(struct pt_regs *regs)
+{
+ return NULL;
+}
+
+
+/*
+ * We assume there is only KVM supporting the callbacks.
+ * Later on, we might change it to a list if there is
+ * another virtualization implementation supporting the callbacks.
+ */
+struct perf_guest_info_callbacks *perf_guest_cbs;
+
+int perf_register_guest_info_callbacks(struct perf_guest_info_callbacks *cbs)
+{
+ perf_guest_cbs = cbs;
+ return 0;
+}
+EXPORT_SYMBOL_GPL(perf_register_guest_info_callbacks);
+
+int perf_unregister_guest_info_callbacks(struct perf_guest_info_callbacks *cbs)
+{
+ perf_guest_cbs = NULL;
+ return 0;
+}
+EXPORT_SYMBOL_GPL(perf_unregister_guest_info_callbacks);
+
+/*
+ * Output
+ */
+static bool perf_output_space(struct perf_buffer *buffer, unsigned long tail,
+ unsigned long offset, unsigned long head)
+{
+ unsigned long mask;
+
+ if (!buffer->writable)
+ return true;
+
+ mask = perf_data_size(buffer) - 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->buffer->poll, POLL_IN);
+
+ if (handle->nmi) {
+ handle->event->pending_wakeup = 1;
+ perf_pending_queue(&handle->event->pending,
+ perf_pending_event);
+ } else
+ perf_event_wakeup(handle->event);
+}
+
+/*
+ * We need to ensure a later event_id doesn't publish a head when a former
+ * event isn't done writing. However since we need to deal with NMIs we
+ * cannot fully serialize things.
+ *
+ * We only publish the head (and generate a wakeup) when the outer-most
+ * event completes.
+ */
+static void perf_output_get_handle(struct perf_output_handle *handle)
+{
+ struct perf_buffer *buffer = handle->buffer;
+
+ preempt_disable();
+ local_inc(&buffer->nest);
+ handle->wakeup = local_read(&buffer->wakeup);
+}
+
+static void perf_output_put_handle(struct perf_output_handle *handle)
+{
+ struct perf_buffer *buffer = handle->buffer;
+ unsigned long head;
+
+again:
+ head = local_read(&buffer->head);
+
+ /*
+ * IRQ/NMI can happen here, which means we can miss a head update.
+ */
+
+ if (!local_dec_and_test(&buffer->nest))
+ goto out;
+
+ /*
+ * Publish the known good head. Rely on the full barrier implied
+ * by atomic_dec_and_test() order the buffer->head read and this
+ * write.
+ */
+ buffer->user_page->data_head = head;
+
+ /*
+ * Now check if we missed an update, rely on the (compiler)
+ * barrier in atomic_dec_and_test() to re-read buffer->head.
+ */
+ if (unlikely(head != local_read(&buffer->head))) {
+ local_inc(&buffer->nest);
+ goto again;
+ }
+
+ if (handle->wakeup != local_read(&buffer->wakeup))
+ perf_output_wakeup(handle);
+
+ out:
+ preempt_enable();
+}
+
+__always_inline void perf_output_copy(struct perf_output_handle *handle,
+ const void *buf, unsigned int len)
+{
+ do {
+ unsigned long size = min_t(unsigned long, handle->size, len);
+
+ memcpy(handle->addr, buf, size);
+
+ len -= size;
+ handle->addr += size;
+ buf += size;
+ handle->size -= size;
+ if (!handle->size) {
+ struct perf_buffer *buffer = handle->buffer;
+
+ handle->page++;
+ handle->page &= buffer->nr_pages - 1;
+ handle->addr = buffer->data_pages[handle->page];
+ handle->size = PAGE_SIZE << page_order(buffer);
+ }
+ } while (len);
+}
+
+int perf_output_begin(struct perf_output_handle *handle,
+ struct perf_event *event, unsigned int size,
+ int nmi, int sample)
+{
+ struct perf_buffer *buffer;
+ 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;
+
+ buffer = rcu_dereference(event->buffer);
+ if (!buffer)
+ goto out;
+
+ handle->buffer = buffer;
+ handle->event = event;
+ handle->nmi = nmi;
+ handle->sample = sample;
+
+ if (!buffer->nr_pages)
+ goto out;
+
+ have_lost = local_read(&buffer->lost);
+ if (have_lost)
+ size += sizeof(lost_event);
+
+ perf_output_get_handle(handle);
+
+ do {
+ /*
+ * Userspace could choose to issue a mb() before updating the
+ * tail pointer. So that all reads will be completed before the
+ * write is issued.
+ */
+ tail = ACCESS_ONCE(buffer->user_page->data_tail);
+ smp_rmb();
+ offset = head = local_read(&buffer->head);
+ head += size;
+ if (unlikely(!perf_output_space(buffer, tail, offset, head)))
+ goto fail;
+ } while (local_cmpxchg(&buffer->head, offset, head) != offset);
+
+ if (head - local_read(&buffer->wakeup) > buffer->watermark)
+ local_add(buffer->watermark, &buffer->wakeup);
+
+ handle->page = offset >> (PAGE_SHIFT + page_order(buffer));
+ handle->page &= buffer->nr_pages - 1;
+ handle->size = offset & ((PAGE_SIZE << page_order(buffer)) - 1);
+ handle->addr = buffer->data_pages[handle->page];
+ handle->addr += handle->size;
+ handle->size = (PAGE_SIZE << page_order(buffer)) - handle->size;
+
+ if (have_lost) {
+ lost_event.header.type = PERF_RECORD_LOST;
+ lost_event.header.misc = 0;
+ lost_event.header.size = sizeof(lost_event);
+ lost_event.id = event->id;
+ lost_event.lost = local_xchg(&buffer->lost, 0);
+
+ perf_output_put(handle, lost_event);
+ }
+
+ return 0;
+
+fail:
+ local_inc(&buffer->lost);
+ perf_output_put_handle(handle);
+out:
+ rcu_read_unlock();
+
+ return -ENOSPC;
+}
+
+void perf_output_end(struct perf_output_handle *handle)
+{
+ struct perf_event *event = handle->event;
+ struct perf_buffer *buffer = handle->buffer;
+
+ int wakeup_events = event->attr.wakeup_events;
+
+ if (handle->sample && wakeup_events) {
+ int events = local_inc_return(&buffer->events);
+ if (events >= wakeup_events) {
+ local_sub(wakeup_events, &buffer->events);
+ local_inc(&buffer->wakeup);
+ }
+ }
+
+ perf_output_put_handle(handle);
+ rcu_read_unlock();
+}
+
+static u32 perf_event_pid(struct perf_event *event, struct task_struct *p)
+{
+ /*
+ * only top level events have the pid namespace they were created in
+ */
+ if (event->parent)
+ event = event->parent;
+
+ return task_tgid_nr_ns(p, event->ns);
+}
+
+static u32 perf_event_tid(struct perf_event *event, struct task_struct *p)
+{
+ /*
+ * only top level events have the pid namespace they were created in
+ */
+ if (event->parent)
+ event = event->parent;
+
+ return task_pid_nr_ns(p, event->ns);
+}
+
+static void perf_output_read_one(struct perf_output_handle *handle,
+ struct perf_event *event)
+{
+ u64 read_format = event->attr.read_format;
+ u64 values[4];
+ int n = 0;
+
+ values[n++] = perf_event_count(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);
+
+ 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++] = perf_event_count(leader);
+ 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++] = perf_event_count(sub);
+ if (read_format & PERF_FORMAT_ID)
+ values[n++] = primary_event_id(sub);
+
+ perf_output_copy(handle, values, n * sizeof(u64));
+ }
+}
+
+static void perf_output_read(struct perf_output_handle *handle,
+ struct perf_event *event)
+{
+ if (event->attr.read_format & PERF_FORMAT_GROUP)
+ perf_output_read_group(handle, event);
+ else
+ perf_output_read_one(handle, event);
+}
+
+void perf_output_sample(struct perf_output_handle *handle,
+ struct perf_event_header *header,
+ struct perf_sample_data *data,
+ struct perf_event *event)
+{
+ u64 sample_type = data->type;
+
+ perf_output_put(handle, *header);
+
+ if (sample_type & PERF_SAMPLE_IP)
+ perf_output_put(handle, data->ip);
+
+ if (sample_type & PERF_SAMPLE_TID)
+ perf_output_put(handle, data->tid_entry);
+
+ if (sample_type & PERF_SAMPLE_TIME)
+ perf_output_put(handle, data->time);
+
+ if (sample_type & PERF_SAMPLE_ADDR)
+ perf_output_put(handle, data->addr);
+
+ if (sample_type & PERF_SAMPLE_ID)
+ perf_output_put(handle, data->id);
+
+ if (sample_type & PERF_SAMPLE_STREAM_ID)
+ perf_output_put(handle, data->stream_id);
+
+ if (sample_type & PERF_SAMPLE_CPU)
+ perf_output_put(handle, data->cpu_entry);
+
+ if (sample_type & PERF_SAMPLE_PERIOD)
+ perf_output_put(handle, data->period);
+
+ if (sample_type & PERF_SAMPLE_READ)
+ perf_output_read(handle, event);
+
+ if (sample_type & PERF_SAMPLE_CALLCHAIN) {
+ if (data->callchain) {
+ int size = 1;
+
+ if (data->callchain)
+ size += data->callchain->nr;
+
+ size *= sizeof(u64);
+
+ perf_output_copy(handle, data->callchain, size);
+ } else {
+ u64 nr = 0;
+ perf_output_put(handle, nr);
+ }
+ }
+
+ if (sample_type & PERF_SAMPLE_RAW) {
+ if (data->raw) {
+ perf_output_put(handle, data->raw->size);
+ perf_output_copy(handle, data->raw->data,
+ data->raw->size);
+ } else {
+ struct {
+ u32 size;
+ u32 data;
+ } raw = {
+ .size = sizeof(u32),
+ .data = 0,
+ };
+ perf_output_put(handle, raw);
+ }
+ }
+}
+
+void perf_prepare_sample(struct perf_event_header *header,
+ struct perf_sample_data *data,
+ struct perf_event *event,
+ struct pt_regs *regs)
+{
+ u64 sample_type = event->attr.sample_type;
+
+ data->type = sample_type;
+
+ header->type = PERF_RECORD_SAMPLE;
+ header->size = sizeof(*header);
+
+ header->misc = 0;
+ header->misc |= perf_misc_flags(regs);
+
+ if (sample_type & PERF_SAMPLE_IP) {
+ data->ip = perf_instruction_pointer(regs);
+
+ header->size += sizeof(data->ip);
+ }
+
+ if (sample_type & PERF_SAMPLE_TID) {
+ /* namespace issues */
+ data->tid_entry.pid = perf_event_pid(event, current);
+ data->tid_entry.tid = perf_event_tid(event, current);
+
+ header->size += sizeof(data->tid_entry);
+ }
+
+ if (sample_type & PERF_SAMPLE_TIME) {
+ data->time = perf_clock();
+
+ header->size += sizeof(data->time);
+ }
+
+ if (sample_type & PERF_SAMPLE_ADDR)
+ header->size += sizeof(data->addr);
+
+ if (sample_type & PERF_SAMPLE_ID) {
+ data->id = primary_event_id(event);
+
+ header->size += sizeof(data->id);
+ }
+
+ if (sample_type & PERF_SAMPLE_STREAM_ID) {
+ data->stream_id = event->id;
+
+ header->size += sizeof(data->stream_id);
+ }
+
+ if (sample_type & PERF_SAMPLE_CPU) {
+ data->cpu_entry.cpu = raw_smp_processor_id();
+ data->cpu_entry.reserved = 0;
+
+ header->size += sizeof(data->cpu_entry);
+ }
+
+ if (sample_type & PERF_SAMPLE_PERIOD)
+ header->size += sizeof(data->period);
+
+ if (sample_type & PERF_SAMPLE_READ)
+ header->size += perf_event_read_size(event);
+
+ if (sample_type & PERF_SAMPLE_CALLCHAIN) {
+ int size = 1;
+
+ data->callchain = perf_callchain(regs);
+
+ if (data->callchain)
+ size += data->callchain->nr;
+
+ header->size += size * sizeof(u64);
+ }
+
+ if (sample_type & PERF_SAMPLE_RAW) {
+ int size = sizeof(u32);
+
+ if (data->raw)
+ size += data->raw->size;
+ else
+ size += sizeof(u32);
+
+ WARN_ON_ONCE(size & (sizeof(u64)-1));
+ header->size += size;
+ }
+}
+
+static void perf_event_output(struct perf_event *event, int nmi,
+ struct perf_sample_data *data,
+ struct pt_regs *regs)
+{
+ struct perf_output_handle handle;
+ struct perf_event_header header;
+
+ perf_prepare_sample(&header, data, event, regs);
+
+ if (perf_output_begin(&handle, event, header.size, nmi, 1))
+ return;
+
+ perf_output_sample(&handle, &header, data, event);
+
+ perf_output_end(&handle);
+}
+
+/*
+ * read event_id
+ */
+
+struct perf_read_event {
+ struct perf_event_header header;
+
+ u32 pid;
+ u32 tid;
+};
+
+static void
+perf_event_read_event(struct perf_event *event,
+ struct task_struct *task)
+{
+ struct perf_output_handle handle;
+ struct perf_read_event read_event = {
+ .header = {
+ .type = PERF_RECORD_READ,
+ .misc = 0,
+ .size = sizeof(read_event) + perf_event_read_size(event),
+ },
+ .pid = perf_event_pid(event, task),
+ .tid = perf_event_tid(event, task),
+ };
+ int ret;
+
+ ret = perf_output_begin(&handle, event, read_event.header.size, 0, 0);
+ if (ret)
+ return;
+
+ perf_output_put(&handle, read_event);
+ perf_output_read(&handle, event);
+
+ perf_output_end(&handle);
+}
+
+/*
+ * task tracking -- fork/exit
+ *
+ * enabled by: attr.comm | attr.mmap | attr.mmap_data | attr.task
+ */
+
+struct perf_task_event {
+ struct task_struct *task;
+ struct perf_event_context *task_ctx;
+
+ struct {
+ struct perf_event_header header;
+
+ u32 pid;
+ u32 ppid;
+ u32 tid;
+ u32 ptid;
+ u64 time;
+ } event_id;
+};
+
+static void perf_event_task_output(struct perf_event *event,
+ struct perf_task_event *task_event)
+{
+ struct perf_output_handle handle;
+ struct task_struct *task = task_event->task;
+ int size, ret;
+
+ size = task_event->event_id.header.size;
+ ret = perf_output_begin(&handle, event, size, 0, 0);
+
+ if (ret)
+ return;
+
+ task_event->event_id.pid = perf_event_pid(event, task);
+ task_event->event_id.ppid = perf_event_pid(event, current);
+
+ task_event->event_id.tid = perf_event_tid(event, task);
+ task_event->event_id.ptid = perf_event_tid(event, current);
+
+ perf_output_put(&handle, task_event->event_id);
+
+ perf_output_end(&handle);
+}
+
+static int perf_event_task_match(struct perf_event *event)
+{
+ if (event->state < PERF_EVENT_STATE_INACTIVE)
+ return 0;
+
+ if (event->cpu != -1 && event->cpu != smp_processor_id())
+ return 0;
+
+ if (event->attr.comm || event->attr.mmap ||
+ event->attr.mmap_data || event->attr.task)
+ return 1;
+
+ return 0;
+}
+
+static void perf_event_task_ctx(struct perf_event_context *ctx,
+ struct perf_task_event *task_event)
+{
+ struct perf_event *event;
+
+ list_for_each_entry_rcu(event, &ctx->event_list, event_entry) {
+ if (perf_event_task_match(event))
+ perf_event_task_output(event, task_event);
+ }
+}
+
+static void perf_event_task_event(struct perf_task_event *task_event)
+{
+ struct perf_cpu_context *cpuctx;
+ struct perf_event_context *ctx = task_event->task_ctx;
+
+ rcu_read_lock();
+ cpuctx = &get_cpu_var(perf_cpu_context);
+ perf_event_task_ctx(&cpuctx->ctx, task_event);
+ if (!ctx)
+ ctx = rcu_dereference(current->perf_event_ctxp);
+ if (ctx)
+ perf_event_task_ctx(ctx, task_event);
+ put_cpu_var(perf_cpu_context);
+ rcu_read_unlock();
+}
+
+static void perf_event_task(struct task_struct *task,
+ struct perf_event_context *task_ctx,
+ int new)
+{
+ struct perf_task_event task_event;
+
+ if (!atomic_read(&nr_comm_events) &&
+ !atomic_read(&nr_mmap_events) &&
+ !atomic_read(&nr_task_events))
+ return;
+
+ task_event = (struct perf_task_event){
+ .task = task,
+ .task_ctx = task_ctx,
+ .event_id = {
+ .header = {
+ .type = new ? PERF_RECORD_FORK : PERF_RECORD_EXIT,
+ .misc = 0,
+ .size = sizeof(task_event.event_id),
+ },
+ /* .pid */
+ /* .ppid */
+ /* .tid */
+ /* .ptid */
+ .time = perf_clock(),
+ },
+ };
+
+ perf_event_task_event(&task_event);
+}
+
+void perf_event_fork(struct task_struct *task)
+{
+ perf_event_task(task, NULL, 1);
+}
+
+/*
+ * comm tracking
+ */
+
+struct perf_comm_event {
+ struct task_struct *task;
+ char *comm;
+ int comm_size;
+
+ struct {
+ struct perf_event_header header;
+
+ u32 pid;
+ u32 tid;
+ } event_id;
+};
+
+static void perf_event_comm_output(struct perf_event *event,
+ struct perf_comm_event *comm_event)
+{
+ struct perf_output_handle handle;
+ int size = comm_event->event_id.header.size;
+ int ret = perf_output_begin(&handle, event, size, 0, 0);
+
+ if (ret)
+ return;
+
+ comm_event->event_id.pid = perf_event_pid(event, comm_event->task);
+ comm_event->event_id.tid = perf_event_tid(event, comm_event->task);
+
+ perf_output_put(&handle, comm_event->event_id);
+ perf_output_copy(&handle, comm_event->comm,
+ comm_event->comm_size);
+ perf_output_end(&handle);
+}
+
+static int perf_event_comm_match(struct perf_event *event)
+{
+ if (event->state < PERF_EVENT_STATE_INACTIVE)
+ return 0;
+
+ if (event->cpu != -1 && event->cpu != smp_processor_id())
+ return 0;
+
+ if (event->attr.comm)
+ return 1;
+
+ return 0;
+}
+
+static void perf_event_comm_ctx(struct perf_event_context *ctx,
+ struct perf_comm_event *comm_event)
+{
+ struct perf_event *event;
+
+ list_for_each_entry_rcu(event, &ctx->event_list, event_entry) {
+ if (perf_event_comm_match(event))
+ perf_event_comm_output(event, comm_event);
+ }
+}
+
+static void perf_event_comm_event(struct perf_comm_event *comm_event)
+{
+ struct perf_cpu_context *cpuctx;
+ struct perf_event_context *ctx;
+ unsigned int size;
+ char comm[TASK_COMM_LEN];
+
+ memset(comm, 0, sizeof(comm));
+ strlcpy(comm, comm_event->task->comm, sizeof(comm));
+ size = ALIGN(strlen(comm)+1, sizeof(u64));
+
+ comm_event->comm = comm;
+ comm_event->comm_size = size;
+
+ comm_event->event_id.header.size = sizeof(comm_event->event_id) + size;
+
+ rcu_read_lock();
+ cpuctx = &get_cpu_var(perf_cpu_context);
+ perf_event_comm_ctx(&cpuctx->ctx, comm_event);
+ ctx = rcu_dereference(current->perf_event_ctxp);
+ if (ctx)
+ perf_event_comm_ctx(ctx, comm_event);
+ put_cpu_var(perf_cpu_context);
+ rcu_read_unlock();
+}
+
+void perf_event_comm(struct task_struct *task)
+{
+ struct perf_comm_event comm_event;
+
+ if (task->perf_event_ctxp)
+ perf_event_enable_on_exec(task);
+
+ if (!atomic_read(&nr_comm_events))
+ return;
+
+ comm_event = (struct perf_comm_event){
+ .task = task,
+ /* .comm */
+ /* .comm_size */
+ .event_id = {
+ .header = {
+ .type = PERF_RECORD_COMM,
+ .misc = 0,
+ /* .size */
+ },
+ /* .pid */
+ /* .tid */
+ },
+ };
+
+ perf_event_comm_event(&comm_event);
+}
+
+/*
+ * mmap tracking
+ */
+
+struct perf_mmap_event {
+ struct vm_area_struct *vma;
+
+ const char *file_name;
+ int file_size;
+
+ struct {
+ struct perf_event_header header;
+
+ u32 pid;
+ u32 tid;
+ u64 start;
+ u64 len;
+ u64 pgoff;
+ } event_id;
+};
+
+static void perf_event_mmap_output(struct perf_event *event,
+ struct perf_mmap_event *mmap_event)
+{
+ struct perf_output_handle handle;
+ int size = mmap_event->event_id.header.size;
+ int ret = perf_output_begin(&handle, event, size, 0, 0);
+
+ if (ret)
+ return;
+
+ mmap_event->event_id.pid = perf_event_pid(event, current);
+ mmap_event->event_id.tid = perf_event_tid(event, current);
+
+ perf_output_put(&handle, mmap_event->event_id);
+ perf_output_copy(&handle, mmap_event->file_name,
+ mmap_event->file_size);
+ perf_output_end(&handle);
+}
+
+static int perf_event_mmap_match(struct perf_event *event,
+ struct perf_mmap_event *mmap_event,
+ int executable)
+{
+ if (event->state < PERF_EVENT_STATE_INACTIVE)
+ return 0;
+
+ if (event->cpu != -1 && event->cpu != smp_processor_id())
+ return 0;
+
+ if ((!executable && event->attr.mmap_data) ||
+ (executable && event->attr.mmap))
+ return 1;
+
+ return 0;
+}
+
+static void perf_event_mmap_ctx(struct perf_event_context *ctx,
+ struct perf_mmap_event *mmap_event,
+ int executable)
+{
+ struct perf_event *event;
+
+ list_for_each_entry_rcu(event, &ctx->event_list, event_entry) {
+ if (perf_event_mmap_match(event, mmap_event, executable))
+ perf_event_mmap_output(event, mmap_event);
+ }
+}
+
+static void perf_event_mmap_event(struct perf_mmap_event *mmap_event)
+{
+ struct perf_cpu_context *cpuctx;
+ struct perf_event_context *ctx;
+ struct vm_area_struct *vma = mmap_event->vma;
+ struct file *file = vma->vm_file;
+ unsigned int size;
+ char tmp[16];
+ char *buf = NULL;
+ const char *name;
+
+ memset(tmp, 0, sizeof(tmp));
+
+ if (file) {
+ /*
+ * d_path works from the end of the buffer backwards, so we
+ * need to add enough zero bytes after the string to handle
+ * the 64bit alignment we do later.
+ */
+ buf = kzalloc(PATH_MAX + sizeof(u64), GFP_KERNEL);
+ if (!buf) {
+ name = strncpy(tmp, "//enomem", sizeof(tmp));
+ goto got_name;
+ }
+ name = d_path(&file->f_path, buf, PATH_MAX);
+ if (IS_ERR(name)) {
+ name = strncpy(tmp, "//toolong", sizeof(tmp));
+ goto got_name;
+ }
+ } else {
+ if (arch_vma_name(mmap_event->vma)) {
+ name = strncpy(tmp, arch_vma_name(mmap_event->vma),
+ sizeof(tmp));
+ goto got_name;
+ }
+
+ if (!vma->vm_mm) {
+ name = strncpy(tmp, "[vdso]", sizeof(tmp));
+ goto got_name;
+ } else if (vma->vm_start <= vma->vm_mm->start_brk &&
+ vma->vm_end >= vma->vm_mm->brk) {
+ name = strncpy(tmp, "[heap]", sizeof(tmp));
+ goto got_name;
+ } else if (vma->vm_start <= vma->vm_mm->start_stack &&
+ vma->vm_end >= vma->vm_mm->start_stack) {
+ name = strncpy(tmp, "[stack]", sizeof(tmp));
+ goto got_name;
+ }
+
+ name = strncpy(tmp, "//anon", sizeof(tmp));
+ goto got_name;
+ }
+
+got_name:
+ size = ALIGN(strlen(name)+1, sizeof(u64));
+
+ mmap_event->file_name = name;
+ mmap_event->file_size = size;
+
+ mmap_event->event_id.header.size = sizeof(mmap_event->event_id) + size;
+
+ rcu_read_lock();
+ cpuctx = &get_cpu_var(perf_cpu_context);
+ perf_event_mmap_ctx(&cpuctx->ctx, mmap_event, vma->vm_flags & VM_EXEC);
+ ctx = rcu_dereference(current->perf_event_ctxp);
+ if (ctx)
+ perf_event_mmap_ctx(ctx, mmap_event, vma->vm_flags & VM_EXEC);
+ put_cpu_var(perf_cpu_context);
+ rcu_read_unlock();
+
+ kfree(buf);
+}
+
+void perf_event_mmap(struct vm_area_struct *vma)
+{
+ struct perf_mmap_event mmap_event;
+
+ if (!atomic_read(&nr_mmap_events))
+ return;
+
+ mmap_event = (struct perf_mmap_event){
+ .vma = vma,
+ /* .file_name */
+ /* .file_size */
+ .event_id = {
+ .header = {
+ .type = PERF_RECORD_MMAP,
+ .misc = PERF_RECORD_MISC_USER,
+ /* .size */
+ },
+ /* .pid */
+ /* .tid */
+ .start = vma->vm_start,
+ .len = vma->vm_end - vma->vm_start,
+ .pgoff = (u64)vma->vm_pgoff << PAGE_SHIFT,
+ },
+ };
+
+ perf_event_mmap_event(&mmap_event);
+}
+
+/*
+ * IRQ throttle logging
+ */
+
+static void perf_log_throttle(struct perf_event *event, int enable)
+{
+ struct perf_output_handle handle;
+ int ret;
+
+ struct {
+ struct perf_event_header header;
+ u64 time;
+ u64 id;
+ u64 stream_id;
+ } throttle_event = {
+ .header = {
+ .type = PERF_RECORD_THROTTLE,
+ .misc = 0,
+ .size = sizeof(throttle_event),
+ },
+ .time = perf_clock(),
+ .id = primary_event_id(event),
+ .stream_id = event->id,
+ };
+
+ if (enable)
+ throttle_event.header.type = PERF_RECORD_UNTHROTTLE;
+
+ ret = perf_output_begin(&handle, event, sizeof(throttle_event), 1, 0);
+ if (ret)
+ return;
+
+ perf_output_put(&handle, throttle_event);
+ perf_output_end(&handle);
+}
+
+/*
+ * Generic event overflow handling, sampling.
+ */
+
+static int __perf_event_overflow(struct perf_event *event, int nmi,
+ int throttle, struct perf_sample_data *data,
+ struct pt_regs *regs)
+{
+ int events = atomic_read(&event->event_limit);
+ struct hw_perf_event *hwc = &event->hw;
+ int ret = 0;
+
+ throttle = (throttle && event->pmu->unthrottle != NULL);
+
+ if (!throttle) {
+ hwc->interrupts++;
+ } else {
+ if (hwc->interrupts != MAX_INTERRUPTS) {
+ hwc->interrupts++;
+ if (HZ * hwc->interrupts >
+ (u64)sysctl_perf_event_sample_rate) {
+ hwc->interrupts = MAX_INTERRUPTS;
+ perf_log_throttle(event, 0);
+ ret = 1;
+ }
+ } else {
+ /*
+ * Keep re-disabling events even though on the previous
+ * pass we disabled it - just in case we raced with a
+ * sched-in and the event got enabled again:
+ */
+ ret = 1;
+ }
+ }
+
+ if (event->attr.freq) {
+ u64 now = perf_clock();
+ s64 delta = now - hwc->freq_time_stamp;
+
+ hwc->freq_time_stamp = now;
+
+ if (delta > 0 && delta < 2*TICK_NSEC)
+ perf_adjust_period(event, delta, hwc->last_period);
+ }
+
+ /*
+ * XXX event_limit might not quite work as expected on inherited
+ * events
+ */
+
+ event->pending_kill = POLL_IN;
+ if (events && atomic_dec_and_test(&event->event_limit)) {
+ ret = 1;
+ event->pending_kill = POLL_HUP;
+ if (nmi) {
+ event->pending_disable = 1;
+ perf_pending_queue(&event->pending,
+ perf_pending_event);
+ } else
+ perf_event_disable(event);
+ }
+
+ if (event->overflow_handler)
+ event->overflow_handler(event, nmi, data, regs);
+ else
+ perf_event_output(event, nmi, data, regs);
+
+ return ret;
+}
+
+int perf_event_overflow(struct perf_event *event, int nmi,
+ struct perf_sample_data *data,
+ struct pt_regs *regs)
+{
+ return __perf_event_overflow(event, nmi, 1, data, regs);
+}
+
+/*
+ * Generic software event infrastructure
+ */
+
+/*
+ * We directly increment event->count and keep a second value in
+ * event->hw.period_left to count intervals. This period event
+ * is kept in the range [-sample_period, 0] so that we can use the
+ * sign as trigger.
+ */
+
+static u64 perf_swevent_set_period(struct perf_event *event)
+{
+ struct hw_perf_event *hwc = &event->hw;
+ u64 period = hwc->last_period;
+ u64 nr, offset;
+ s64 old, val;
+
+ hwc->last_period = hwc->sample_period;
+
+again:
+ old = val = local64_read(&hwc->period_left);
+ if (val < 0)
+ return 0;
+
+ nr = div64_u64(period + val, period);
+ offset = nr * period;
+ val -= offset;
+ if (local64_cmpxchg(&hwc->period_left, old, val) != old)
+ goto again;
+
+ return nr;
+}
+
+static void perf_swevent_overflow(struct perf_event *event, u64 overflow,
+ int nmi, struct perf_sample_data *data,
+ struct pt_regs *regs)
+{
+ struct hw_perf_event *hwc = &event->hw;
+ int throttle = 0;
+
+ data->period = event->hw.last_period;
+ if (!overflow)
+ overflow = perf_swevent_set_period(event);
+
+ if (hwc->interrupts == MAX_INTERRUPTS)
+ return;
+
+ for (; overflow; overflow--) {
+ if (__perf_event_overflow(event, nmi, throttle,
+ data, regs)) {
+ /*
+ * We inhibit the overflow from happening when
+ * hwc->interrupts == MAX_INTERRUPTS.
+ */
+ break;
+ }
+ throttle = 1;
+ }
+}
+
+static void perf_swevent_add(struct perf_event *event, u64 nr,
+ int nmi, struct perf_sample_data *data,
+ struct pt_regs *regs)
+{
+ struct hw_perf_event *hwc = &event->hw;
+
+ local64_add(nr, &event->count);
+
+ if (!regs)
+ return;
+
+ if (!hwc->sample_period)
+ return;
+
+ if (nr == 1 && hwc->sample_period == 1 && !event->attr.freq)
+ return perf_swevent_overflow(event, 1, nmi, data, regs);
+
+ if (local64_add_negative(nr, &hwc->period_left))
+ return;
+
+ perf_swevent_overflow(event, 0, nmi, data, regs);
+}
+
+static int perf_exclude_event(struct perf_event *event,
+ struct pt_regs *regs)
+{
+ if (regs) {
+ if (event->attr.exclude_user && user_mode(regs))
+ return 1;
+
+ if (event->attr.exclude_kernel && !user_mode(regs))
+ return 1;
+ }
+
+ return 0;
+}
+
+static int perf_swevent_match(struct perf_event *event,
+ enum perf_type_id type,
+ u32 event_id,
+ struct perf_sample_data *data,
+ struct pt_regs *regs)
+{
+ if (event->attr.type != type)
+ return 0;
+
+ if (event->attr.config != event_id)
+ return 0;
+
+ if (perf_exclude_event(event, regs))
+ return 0;
+
+ return 1;
+}
+
+static inline u64 swevent_hash(u64 type, u32 event_id)
+{
+ u64 val = event_id | (type << 32);
+
+ return hash_64(val, SWEVENT_HLIST_BITS);
+}
+
+static inline struct hlist_head *
+__find_swevent_head(struct swevent_hlist *hlist, u64 type, u32 event_id)
+{
+ u64 hash = swevent_hash(type, event_id);
+
+ return &hlist->heads[hash];
+}
+
+/* For the read side: events when they trigger */
+static inline struct hlist_head *
+find_swevent_head_rcu(struct perf_cpu_context *ctx, u64 type, u32 event_id)
+{
+ struct swevent_hlist *hlist;
+
+ hlist = rcu_dereference(ctx->swevent_hlist);
+ if (!hlist)
+ return NULL;
+
+ return __find_swevent_head(hlist, type, event_id);
+}
+
+/* For the event head insertion and removal in the hlist */
+static inline struct hlist_head *
+find_swevent_head(struct perf_cpu_context *ctx, struct perf_event *event)
+{
+ struct swevent_hlist *hlist;
+ u32 event_id = event->attr.config;
+ u64 type = event->attr.type;
+
+ /*
+ * Event scheduling is always serialized against hlist allocation
+ * and release. Which makes the protected version suitable here.
+ * The context lock guarantees that.
+ */
+ hlist = rcu_dereference_protected(ctx->swevent_hlist,
+ lockdep_is_held(&event->ctx->lock));
+ if (!hlist)
+ return NULL;
+
+ return __find_swevent_head(hlist, type, event_id);
+}
+
+static void do_perf_sw_event(enum perf_type_id type, u32 event_id,
+ u64 nr, int nmi,
+ struct perf_sample_data *data,
+ struct pt_regs *regs)
+{
+ struct perf_cpu_context *cpuctx;
+ struct perf_event *event;
+ struct hlist_node *node;
+ struct hlist_head *head;
+
+ cpuctx = &__get_cpu_var(perf_cpu_context);
+
+ rcu_read_lock();
+
+ head = find_swevent_head_rcu(cpuctx, type, event_id);
+
+ if (!head)
+ goto end;
+
+ hlist_for_each_entry_rcu(event, node, head, hlist_entry) {
+ if (perf_swevent_match(event, type, event_id, data, regs))
+ perf_swevent_add(event, nr, nmi, data, regs);
+ }
+end:
+ rcu_read_unlock();
+}
+
+int perf_swevent_get_recursion_context(void)
+{
+ struct perf_cpu_context *cpuctx = &__get_cpu_var(perf_cpu_context);
+ int rctx;
+
+ if (in_nmi())
+ rctx = 3;
+ else if (in_irq())
+ rctx = 2;
+ else if (in_softirq())
+ rctx = 1;
+ else
+ rctx = 0;
+
+ if (cpuctx->recursion[rctx])
+ return -1;
+
+ cpuctx->recursion[rctx]++;
+ barrier();
+
+ return rctx;
+}
+EXPORT_SYMBOL_GPL(perf_swevent_get_recursion_context);
+
+void inline perf_swevent_put_recursion_context(int rctx)
+{
+ struct perf_cpu_context *cpuctx = &__get_cpu_var(perf_cpu_context);
+ barrier();
+ cpuctx->recursion[rctx]--;
+}
+
+void __perf_sw_event(u32 event_id, u64 nr, int nmi,
+ struct pt_regs *regs, u64 addr)
+{
+ struct perf_sample_data data;
+ int rctx;
+
+ preempt_disable_notrace();
+ rctx = perf_swevent_get_recursion_context();
+ if (rctx < 0)
+ return;
+
+ perf_sample_data_init(&data, addr);
+
+ do_perf_sw_event(PERF_TYPE_SOFTWARE, event_id, nr, nmi, &data, regs);
+
+ perf_swevent_put_recursion_context(rctx);
+ preempt_enable_notrace();
+}
+
+static void perf_swevent_read(struct perf_event *event)
+{
+}
+
+static int perf_swevent_enable(struct perf_event *event)
+{
+ struct hw_perf_event *hwc = &event->hw;
+ struct perf_cpu_context *cpuctx;
+ struct hlist_head *head;
+
+ cpuctx = &__get_cpu_var(perf_cpu_context);
+
+ if (hwc->sample_period) {
+ hwc->last_period = hwc->sample_period;
+ perf_swevent_set_period(event);
+ }
+
+ head = find_swevent_head(cpuctx, event);
+ if (WARN_ON_ONCE(!head))
+ return -EINVAL;
+
+ hlist_add_head_rcu(&event->hlist_entry, head);
+
+ return 0;
+}
+
+static void perf_swevent_disable(struct perf_event *event)
+{
+ hlist_del_rcu(&event->hlist_entry);
+}
+
+static void perf_swevent_void(struct perf_event *event)
+{
+}
+
+static int perf_swevent_int(struct perf_event *event)
+{
+ return 0;
+}
+
+static const struct pmu perf_ops_generic = {
+ .enable = perf_swevent_enable,
+ .disable = perf_swevent_disable,
+ .start = perf_swevent_int,
+ .stop = perf_swevent_void,
+ .read = perf_swevent_read,
+ .unthrottle = perf_swevent_void, /* hwc->interrupts already reset */
+};
+
+/*
+ * hrtimer based swevent callback
+ */
+
+static enum hrtimer_restart perf_swevent_hrtimer(struct hrtimer *hrtimer)
+{
+ enum hrtimer_restart ret = HRTIMER_RESTART;
+ struct perf_sample_data data;
+ struct pt_regs *regs;
+ struct perf_event *event;
+ u64 period;
+
+ event = container_of(hrtimer, struct perf_event, hw.hrtimer);
+ event->pmu->read(event);
+
+ perf_sample_data_init(&data, 0);
+ data.period = event->hw.last_period;
+ regs = get_irq_regs();
+
+ if (regs && !perf_exclude_event(event, regs)) {
+ if (!(event->attr.exclude_idle && current->pid == 0))
+ if (perf_event_overflow(event, 0, &data, regs))
+ ret = HRTIMER_NORESTART;
+ }
+
+ period = max_t(u64, 10000, event->hw.sample_period);
+ hrtimer_forward_now(hrtimer, ns_to_ktime(period));
+
+ return ret;
+}
+
+static void perf_swevent_start_hrtimer(struct perf_event *event)
+{
+ struct hw_perf_event *hwc = &event->hw;
+
+ hrtimer_init(&hwc->hrtimer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
+ hwc->hrtimer.function = perf_swevent_hrtimer;
+ if (hwc->sample_period) {
+ u64 period;
+
+ if (hwc->remaining) {
+ if (hwc->remaining < 0)
+ period = 10000;
+ else
+ period = hwc->remaining;
+ hwc->remaining = 0;
+ } else {
+ period = max_t(u64, 10000, hwc->sample_period);
+ }
+ __hrtimer_start_range_ns(&hwc->hrtimer,
+ ns_to_ktime(period), 0,
+ HRTIMER_MODE_REL, 0);
+ }
+}
+
+static void perf_swevent_cancel_hrtimer(struct perf_event *event)
+{
+ struct hw_perf_event *hwc = &event->hw;
+
+ if (hwc->sample_period) {
+ ktime_t remaining = hrtimer_get_remaining(&hwc->hrtimer);
+ hwc->remaining = ktime_to_ns(remaining);
+
+ hrtimer_cancel(&hwc->hrtimer);
+ }
+}
+
+/*
+ * Software event: cpu wall time clock
+ */
+
+static void cpu_clock_perf_event_update(struct perf_event *event)
+{
+ int cpu = raw_smp_processor_id();
+ s64 prev;
+ u64 now;
+
+ now = cpu_clock(cpu);
+ prev = local64_xchg(&event->hw.prev_count, now);
+ local64_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();
+
+ local64_set(&hwc->prev_count, cpu_clock(cpu));
+ perf_swevent_start_hrtimer(event);
+
+ return 0;
+}
+
+static void cpu_clock_perf_event_disable(struct perf_event *event)
+{
+ perf_swevent_cancel_hrtimer(event);
+ cpu_clock_perf_event_update(event);
+}
+
+static void cpu_clock_perf_event_read(struct perf_event *event)
+{
+ cpu_clock_perf_event_update(event);
+}
+
+static const struct pmu perf_ops_cpu_clock = {
+ .enable = cpu_clock_perf_event_enable,
+ .disable = cpu_clock_perf_event_disable,
+ .read = cpu_clock_perf_event_read,
+};
+
+/*
+ * Software event: task time clock
+ */
+
+static void task_clock_perf_event_update(struct perf_event *event, u64 now)
+{
+ u64 prev;
+ s64 delta;
+
+ prev = local64_xchg(&event->hw.prev_count, now);
+ delta = now - prev;
+ local64_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;
+
+ local64_set(&hwc->prev_count, now);
+
+ perf_swevent_start_hrtimer(event);
+
+ return 0;
+}
+
+static void task_clock_perf_event_disable(struct perf_event *event)
+{
+ perf_swevent_cancel_hrtimer(event);
+ task_clock_perf_event_update(event, event->ctx->time);
+
+}
+
+static void task_clock_perf_event_read(struct perf_event *event)
+{
+ u64 time;
+
+ if (!in_nmi()) {
+ update_context_time(event->ctx);
+ time = event->ctx->time;
+ } else {
+ u64 now = perf_clock();
+ u64 delta = now - event->ctx->timestamp;
+ time = event->ctx->time + delta;
+ }
+
+ task_clock_perf_event_update(event, time);
+}
+
+static const struct pmu perf_ops_task_clock = {
+ .enable = task_clock_perf_event_enable,
+ .disable = task_clock_perf_event_disable,
+ .read = task_clock_perf_event_read,
+};
+
+/* Deref the hlist from the update side */
+static inline struct swevent_hlist *
+swevent_hlist_deref(struct perf_cpu_context *cpuctx)
+{
+ return rcu_dereference_protected(cpuctx->swevent_hlist,
+ lockdep_is_held(&cpuctx->hlist_mutex));
+}
+
+static void swevent_hlist_release_rcu(struct rcu_head *rcu_head)
+{
+ struct swevent_hlist *hlist;
+
+ hlist = container_of(rcu_head, struct swevent_hlist, rcu_head);
+ kfree(hlist);
+}
+
+static void swevent_hlist_release(struct perf_cpu_context *cpuctx)
+{
+ struct swevent_hlist *hlist = swevent_hlist_deref(cpuctx);
+
+ if (!hlist)
+ return;
+
+ rcu_assign_pointer(cpuctx->swevent_hlist, NULL);
+ call_rcu(&hlist->rcu_head, swevent_hlist_release_rcu);
+}
+
+static void swevent_hlist_put_cpu(struct perf_event *event, int cpu)
+{
+ struct perf_cpu_context *cpuctx = &per_cpu(perf_cpu_context, cpu);
+
+ mutex_lock(&cpuctx->hlist_mutex);
+
+ if (!--cpuctx->hlist_refcount)
+ swevent_hlist_release(cpuctx);
+
+ mutex_unlock(&cpuctx->hlist_mutex);
+}
+
+static void swevent_hlist_put(struct perf_event *event)
+{
+ int cpu;
+
+ if (event->cpu != -1) {
+ swevent_hlist_put_cpu(event, event->cpu);
+ return;
+ }
+
+ for_each_possible_cpu(cpu)
+ swevent_hlist_put_cpu(event, cpu);
+}
+
+static int swevent_hlist_get_cpu(struct perf_event *event, int cpu)
+{
+ struct perf_cpu_context *cpuctx = &per_cpu(perf_cpu_context, cpu);
+ int err = 0;
+
+ mutex_lock(&cpuctx->hlist_mutex);
+
+ if (!swevent_hlist_deref(cpuctx) && cpu_online(cpu)) {
+ struct swevent_hlist *hlist;
+
+ hlist = kzalloc(sizeof(*hlist), GFP_KERNEL);
+ if (!hlist) {
+ err = -ENOMEM;
+ goto exit;
+ }
+ rcu_assign_pointer(cpuctx->swevent_hlist, hlist);
+ }
+ cpuctx->hlist_refcount++;
+ exit:
+ mutex_unlock(&cpuctx->hlist_mutex);
+
+ return err;
+}
+
+static int swevent_hlist_get(struct perf_event *event)
+{
+ int err;
+ int cpu, failed_cpu;
+
+ if (event->cpu != -1)
+ return swevent_hlist_get_cpu(event, event->cpu);
+
+ get_online_cpus();
+ for_each_possible_cpu(cpu) {
+ err = swevent_hlist_get_cpu(event, cpu);
+ if (err) {
+ failed_cpu = cpu;
+ goto fail;
+ }
+ }
+ put_online_cpus();
+
+ return 0;
+ fail:
+ for_each_possible_cpu(cpu) {
+ if (cpu == failed_cpu)
+ break;
+ swevent_hlist_put_cpu(event, cpu);
+ }
+
+ put_online_cpus();
+ return err;
+}
+
+#ifdef CONFIG_EVENT_TRACING
+
+static const struct pmu perf_ops_tracepoint = {
+ .enable = perf_trace_enable,
+ .disable = perf_trace_disable,
+ .start = perf_swevent_int,
+ .stop = perf_swevent_void,
+ .read = perf_swevent_read,
+ .unthrottle = perf_swevent_void,
+};
+
+static int perf_tp_filter_match(struct perf_event *event,
+ struct perf_sample_data *data)
+{
+ void *record = data->raw->data;
+
+ if (likely(!event->filter) || filter_match_preds(event->filter, record))
+ return 1;
+ return 0;
+}
+
+static int perf_tp_event_match(struct perf_event *event,
+ struct perf_sample_data *data,
+ struct pt_regs *regs)
+{
+ /*
+ * All tracepoints are from kernel-space.
+ */
+ if (event->attr.exclude_kernel)
+ return 0;
+
+ if (!perf_tp_filter_match(event, data))
+ return 0;
+
+ return 1;
+}
+
+void perf_tp_event(u64 addr, u64 count, void *record, int entry_size,
+ struct pt_regs *regs, struct hlist_head *head, int rctx)
+{
+ struct perf_sample_data data;
+ struct perf_event *event;
+ struct hlist_node *node;
+
+ struct perf_raw_record raw = {
+ .size = entry_size,
+ .data = record,
+ };
+
+ perf_sample_data_init(&data, addr);
+ data.raw = &raw;
+
+ hlist_for_each_entry_rcu(event, node, head, hlist_entry) {
+ if (perf_tp_event_match(event, &data, regs))
+ perf_swevent_add(event, count, 1, &data, regs);
+ }
+
+ perf_swevent_put_recursion_context(rctx);
+}
+EXPORT_SYMBOL_GPL(perf_tp_event);
+
+static void tp_perf_event_destroy(struct perf_event *event)
+{
+ perf_trace_destroy(event);
+}
+
+static const struct pmu *tp_perf_event_init(struct perf_event *event)
+{
+ int err;
+
+ /*
+ * Raw tracepoint data is a severe data leak, only allow root to
+ * have these.
+ */
+ if ((event->attr.sample_type & PERF_SAMPLE_RAW) &&
+ perf_paranoid_tracepoint_raw() &&
+ !capable(CAP_SYS_ADMIN))
+ return ERR_PTR(-EPERM);
+
+ err = perf_trace_init(event);
+ if (err)
+ return NULL;
+
+ event->destroy = tp_perf_event_destroy;
+
+ return &perf_ops_tracepoint;
+}
+
+static int perf_event_set_filter(struct perf_event *event, void __user *arg)
+{
+ char *filter_str;
+ int ret;
+
+ if (event->attr.type != PERF_TYPE_TRACEPOINT)
+ return -EINVAL;
+
+ filter_str = strndup_user(arg, PAGE_SIZE);
+ if (IS_ERR(filter_str))
+ return PTR_ERR(filter_str);
+
+ ret = ftrace_profile_set_filter(event, event->attr.config, filter_str);
+
+ kfree(filter_str);
+ return ret;
+}
+
+static void perf_event_free_filter(struct perf_event *event)
+{
+ ftrace_profile_free_filter(event);
+}
+
+#else
+
+static const struct pmu *tp_perf_event_init(struct perf_event *event)
+{
+ return NULL;
+}
+
+static int perf_event_set_filter(struct perf_event *event, void __user *arg)
+{
+ return -ENOENT;
+}
+
+static void perf_event_free_filter(struct perf_event *event)
+{
+}
+
+#endif /* CONFIG_EVENT_TRACING */
+
+#ifdef CONFIG_HAVE_HW_BREAKPOINT
+static void bp_perf_event_destroy(struct perf_event *event)
+{
+ release_bp_slot(event);
+}
+
+static const struct pmu *bp_perf_event_init(struct perf_event *bp)
+{
+ int err;
+
+ err = register_perf_hw_breakpoint(bp);
+ if (err)
+ return ERR_PTR(err);
+
+ bp->destroy = bp_perf_event_destroy;
+
+ return &perf_ops_bp;
+}
+
+void perf_bp_event(struct perf_event *bp, void *data)
+{
+ struct perf_sample_data sample;
+ struct pt_regs *regs = data;
+
+ perf_sample_data_init(&sample, bp->attr.bp_addr);
+
+ if (!perf_exclude_event(bp, regs))
+ perf_swevent_add(bp, 1, 1, &sample, regs);
+}
+#else
+static const struct pmu *bp_perf_event_init(struct perf_event *bp)
+{
+ return NULL;
+}
+
+void perf_bp_event(struct perf_event *bp, void *regs)
+{
+}
+#endif
+
+atomic_t perf_swevent_enabled[PERF_COUNT_SW_MAX];
+
+static void sw_perf_event_destroy(struct perf_event *event)
+{
+ u64 event_id = event->attr.config;
+
+ WARN_ON(event->parent);
+
+ atomic_dec(&perf_swevent_enabled[event_id]);
+ swevent_hlist_put(event);
+}
+
+static const struct pmu *sw_perf_event_init(struct perf_event *event)
+{
+ const struct pmu *pmu = NULL;
+ u64 event_id = event->attr.config;
+
+ /*
+ * Software events (currently) can't in general distinguish
+ * between user, kernel and hypervisor events.
+ * However, context switches and cpu migrations are considered
+ * to be kernel events, and page faults are never hypervisor
+ * events.
+ */
+ switch (event_id) {
+ case PERF_COUNT_SW_CPU_CLOCK:
+ pmu = &perf_ops_cpu_clock;
+
+ break;
+ case PERF_COUNT_SW_TASK_CLOCK:
+ /*
+ * If the user instantiates this as a per-cpu event,
+ * use the cpu_clock event instead.
+ */
+ if (event->ctx->task)
+ pmu = &perf_ops_task_clock;
+ else
+ pmu = &perf_ops_cpu_clock;
+
+ break;
+ case PERF_COUNT_SW_PAGE_FAULTS:
+ case PERF_COUNT_SW_PAGE_FAULTS_MIN:
+ case PERF_COUNT_SW_PAGE_FAULTS_MAJ:
+ case PERF_COUNT_SW_CONTEXT_SWITCHES:
+ case PERF_COUNT_SW_CPU_MIGRATIONS:
+ case PERF_COUNT_SW_ALIGNMENT_FAULTS:
+ case PERF_COUNT_SW_EMULATION_FAULTS:
+ if (!event->parent) {
+ int err;
+
+ err = swevent_hlist_get(event);
+ if (err)
+ return ERR_PTR(err);
+
+ atomic_inc(&perf_swevent_enabled[event_id]);
+ event->destroy = sw_perf_event_destroy;
+ }
+ pmu = &perf_ops_generic;
+ break;
+ }
+
+ return pmu;
+}
+
+/*
+ * Allocate and initialize a event structure
+ */
+static struct perf_event *
+perf_event_alloc(struct perf_event_attr *attr,
+ int cpu,
+ struct perf_event_context *ctx,
+ struct perf_event *group_leader,
+ struct perf_event *parent_event,
+ perf_overflow_handler_t overflow_handler,
+ gfp_t gfpflags)
+{
+ const struct pmu *pmu;
+ struct perf_event *event;
+ struct hw_perf_event *hwc;
+ long err;
+
+ event = kzalloc(sizeof(*event), gfpflags);
+ if (!event)
+ return ERR_PTR(-ENOMEM);
+
+ /*
+ * Single events are their own group leaders, with an
+ * empty sibling list:
+ */
+ if (!group_leader)
+ group_leader = event;
+
+ mutex_init(&event->child_mutex);
+ INIT_LIST_HEAD(&event->child_list);
+
+ INIT_LIST_HEAD(&event->group_entry);
+ INIT_LIST_HEAD(&event->event_entry);
+ INIT_LIST_HEAD(&event->sibling_list);
+ init_waitqueue_head(&event->waitq);
+
+ mutex_init(&event->mmap_mutex);
+
+ event->cpu = cpu;
+ event->attr = *attr;
+ event->group_leader = group_leader;
+ event->pmu = NULL;
+ event->ctx = ctx;
+ event->oncpu = -1;
+
+ event->parent = parent_event;
+
+ event->ns = get_pid_ns(current->nsproxy->pid_ns);
+ event->id = atomic64_inc_return(&perf_event_id);
+
+ event->state = PERF_EVENT_STATE_INACTIVE;
+
+ if (!overflow_handler && parent_event)
+ overflow_handler = parent_event->overflow_handler;
+
+ event->overflow_handler = overflow_handler;
+
+ if (attr->disabled)
+ event->state = PERF_EVENT_STATE_OFF;
+
+ pmu = NULL;
+
+ hwc = &event->hw;
+ hwc->sample_period = attr->sample_period;
+ if (attr->freq && attr->sample_freq)
+ hwc->sample_period = 1;
+ hwc->last_period = hwc->sample_period;
+
+ local64_set(&hwc->period_left, hwc->sample_period);
+
+ /*
+ * we currently do not support PERF_FORMAT_GROUP on inherited events
+ */
+ if (attr->inherit && (attr->read_format & PERF_FORMAT_GROUP))
+ goto done;
+
+ switch (attr->type) {
+ case PERF_TYPE_RAW:
+ case PERF_TYPE_HARDWARE:
+ case PERF_TYPE_HW_CACHE:
+ pmu = hw_perf_event_init(event);
+ break;
+
+ case PERF_TYPE_SOFTWARE:
+ pmu = sw_perf_event_init(event);
+ break;
+
+ case PERF_TYPE_TRACEPOINT:
+ pmu = tp_perf_event_init(event);
+ break;
+
+ case PERF_TYPE_BREAKPOINT:
+ pmu = bp_perf_event_init(event);
+ break;
+
+
+ default:
+ break;
+ }
+done:
+ err = 0;
+ if (!pmu)
+ err = -EINVAL;
+ else if (IS_ERR(pmu))
+ err = PTR_ERR(pmu);
+
+ if (err) {
+ if (event->ns)
+ put_pid_ns(event->ns);
+ kfree(event);
+ return ERR_PTR(err);
+ }
+
+ event->pmu = pmu;
+
+ if (!event->parent) {
+ atomic_inc(&nr_events);
+ if (event->attr.mmap || event->attr.mmap_data)
+ atomic_inc(&nr_mmap_events);
+ if (event->attr.comm)
+ atomic_inc(&nr_comm_events);
+ if (event->attr.task)
+ atomic_inc(&nr_task_events);
+ }
+
+ return event;
+}
+
+static int perf_copy_attr(struct perf_event_attr __user *uattr,
+ struct perf_event_attr *attr)
+{
+ u32 size;
+ int ret;
+
+ if (!access_ok(VERIFY_WRITE, uattr, PERF_ATTR_SIZE_VER0))
+ return -EFAULT;
+
+ /*
+ * zero the full structure, so that a short copy will be nice.
+ */
+ memset(attr, 0, sizeof(*attr));
+
+ ret = get_user(size, &uattr->size);
+ if (ret)
+ return ret;
+
+ if (size > PAGE_SIZE) /* silly large */
+ goto err_size;
+
+ if (!size) /* abi compat */
+ size = PERF_ATTR_SIZE_VER0;
+
+ if (size < PERF_ATTR_SIZE_VER0)
+ goto err_size;
+
+ /*
+ * If we're handed a bigger struct than we know of,
+ * ensure all the unknown bits are 0 - i.e. new
+ * user-space does not rely on any kernel feature
+ * extensions we dont know about yet.
+ */
+ if (size > sizeof(*attr)) {
+ unsigned char __user *addr;
+ unsigned char __user *end;
+ unsigned char val;
+
+ addr = (void __user *)uattr + sizeof(*attr);
+ end = (void __user *)uattr + size;
+
+ for (; addr < end; addr++) {
+ ret = get_user(val, addr);
+ if (ret)
+ return ret;
+ if (val)
+ goto err_size;
+ }
+ size = sizeof(*attr);
+ }
+
+ ret = copy_from_user(attr, uattr, size);
+ if (ret)
+ return -EFAULT;
+
+ /*
+ * If the type exists, the corresponding creation will verify
+ * the attr->config.
+ */
+ if (attr->type >= PERF_TYPE_MAX)
+ return -EINVAL;
+
+ if (attr->__reserved_1)
+ return -EINVAL;
+
+ if (attr->sample_type & ~(PERF_SAMPLE_MAX-1))
+ return -EINVAL;
+
+ if (attr->read_format & ~(PERF_FORMAT_MAX-1))
+ return -EINVAL;
+
+out:
+ return ret;
+
+err_size:
+ put_user(sizeof(*attr), &uattr->size);
+ ret = -E2BIG;
+ goto out;
+}
+
+static int
+perf_event_set_output(struct perf_event *event, struct perf_event *output_event)
+{
+ struct perf_buffer *buffer = NULL, *old_buffer = NULL;
+ int ret = -EINVAL;
+
+ if (!output_event)
+ goto set;
+
+ /* don't allow circular references */
+ if (event == output_event)
+ goto out;
+
+ /*
+ * Don't allow cross-cpu buffers
+ */
+ if (output_event->cpu != event->cpu)
+ goto out;
+
+ /*
+ * If its not a per-cpu buffer, it must be the same task.
+ */
+ if (output_event->cpu == -1 && output_event->ctx != event->ctx)
+ goto out;
+
+set:
+ mutex_lock(&event->mmap_mutex);
+ /* Can't redirect output if we've got an active mmap() */
+ if (atomic_read(&event->mmap_count))
+ goto unlock;
+
+ if (output_event) {
+ /* get the buffer we want to redirect to */
+ buffer = perf_buffer_get(output_event);
+ if (!buffer)
+ goto unlock;
+ }
+
+ old_buffer = event->buffer;
+ rcu_assign_pointer(event->buffer, buffer);
+ ret = 0;
+unlock:
+ mutex_unlock(&event->mmap_mutex);
+
+ if (old_buffer)
+ perf_buffer_put(old_buffer);
+out:
+ return ret;
+}
+
+/**
+ * sys_perf_event_open - open a performance event, associate it to a task/cpu
+ *
+ * @attr_uptr: event_id type attributes for monitoring/sampling
+ * @pid: target pid
+ * @cpu: target cpu
+ * @group_fd: group leader event fd
+ */
+SYSCALL_DEFINE5(perf_event_open,
+ struct perf_event_attr __user *, attr_uptr,
+ pid_t, pid, int, cpu, int, group_fd, unsigned long, flags)
+{
+ struct perf_event *event, *group_leader = NULL, *output_event = NULL;
+ struct perf_event_attr attr;
+ struct perf_event_context *ctx;
+ struct file *event_file = NULL;
+ struct file *group_file = NULL;
+ int event_fd;
+ int fput_needed = 0;
+ int err;
+
+ /* for future expandability... */
+ if (flags & ~(PERF_FLAG_FD_NO_GROUP | PERF_FLAG_FD_OUTPUT))
+ return -EINVAL;
+
+ err = perf_copy_attr(attr_uptr, &attr);
+ if (err)
+ return err;
+
+ if (!attr.exclude_kernel) {
+ if (perf_paranoid_kernel() && !capable(CAP_SYS_ADMIN))
+ return -EACCES;
+ }
+
+ if (attr.freq) {
+ if (attr.sample_freq > sysctl_perf_event_sample_rate)
+ return -EINVAL;
+ }
+
+ event_fd = get_unused_fd_flags(O_RDWR);
+ if (event_fd < 0)
+ return event_fd;
+
+ /*
+ * Get the target context (task or percpu):
+ */
+ ctx = find_get_context(pid, cpu);
+ if (IS_ERR(ctx)) {
+ err = PTR_ERR(ctx);
+ goto err_fd;
+ }
+
+ if (group_fd != -1) {
+ group_leader = perf_fget_light(group_fd, &fput_needed);
+ if (IS_ERR(group_leader)) {
+ err = PTR_ERR(group_leader);
+ goto err_put_context;
+ }
+ group_file = group_leader->filp;
+ if (flags & PERF_FLAG_FD_OUTPUT)
+ output_event = group_leader;
+ if (flags & PERF_FLAG_FD_NO_GROUP)
+ group_leader = NULL;
+ }
+
+ /*
+ * Look up the group leader (we will attach this event to it):
+ */
+ if (group_leader) {
+ err = -EINVAL;
+
+ /*
+ * Do not allow a recursive hierarchy (this new sibling
+ * becoming part of another group-sibling):
+ */
+ if (group_leader->group_leader != group_leader)
+ goto err_put_context;
+ /*
+ * Do not allow to attach to a group in a different
+ * task or CPU context:
+ */
+ if (group_leader->ctx != ctx)
+ goto err_put_context;
+ /*
+ * Only a group leader can be exclusive or pinned
+ */
+ if (attr.exclusive || attr.pinned)
+ goto err_put_context;
+ }
+
+ event = perf_event_alloc(&attr, cpu, ctx, group_leader,
+ NULL, NULL, GFP_KERNEL);
+ if (IS_ERR(event)) {
+ err = PTR_ERR(event);
+ goto err_put_context;
+ }
+
+ if (output_event) {
+ err = perf_event_set_output(event, output_event);
+ if (err)
+ goto err_free_put_context;
+ }
+
+ event_file = anon_inode_getfile("[perf_event]", &perf_fops, event, O_RDWR);
+ if (IS_ERR(event_file)) {
+ err = PTR_ERR(event_file);
+ goto err_free_put_context;
+ }
+
+ event->filp = event_file;
+ WARN_ON_ONCE(ctx->parent_ctx);
+ mutex_lock(&ctx->mutex);
+ perf_install_in_context(ctx, event, cpu);
+ ++ctx->generation;
+ mutex_unlock(&ctx->mutex);
+
+ event->owner = current;
+ get_task_struct(current);
+ mutex_lock(&current->perf_event_mutex);
+ list_add_tail(&event->owner_entry, &current->perf_event_list);
+ mutex_unlock(&current->perf_event_mutex);
+
+ /*
+ * Drop the reference on the group_event after placing the
+ * new event on the sibling_list. This ensures destruction
+ * of the group leader will find the pointer to itself in
+ * perf_group_detach().
+ */
+ fput_light(group_file, fput_needed);
+ fd_install(event_fd, event_file);
+ return event_fd;
+
+err_free_put_context:
+ free_event(event);
+err_put_context:
+ fput_light(group_file, fput_needed);
+ put_ctx(ctx);
+err_fd:
+ put_unused_fd(event_fd);
+ return err;
+}
+
+/**
+ * perf_event_create_kernel_counter
+ *
+ * @attr: attributes of the counter to create
+ * @cpu: cpu in which the counter is bound
+ * @pid: task to profile
+ */
+struct perf_event *
+perf_event_create_kernel_counter(struct perf_event_attr *attr, int cpu,
+ pid_t pid,
+ perf_overflow_handler_t overflow_handler)
+{
+ struct perf_event *event;
+ struct perf_event_context *ctx;
+ int err;
+
+ /*
+ * Get the target context (task or percpu):
+ */
+
+ ctx = find_get_context(pid, cpu);
+ if (IS_ERR(ctx)) {
+ err = PTR_ERR(ctx);
+ goto err_exit;
+ }
+
+ event = perf_event_alloc(attr, cpu, ctx, NULL,
+ NULL, overflow_handler, GFP_KERNEL);
+ if (IS_ERR(event)) {
+ err = PTR_ERR(event);
+ goto err_put_context;
+ }
+
+ event->filp = NULL;
+ WARN_ON_ONCE(ctx->parent_ctx);
+ mutex_lock(&ctx->mutex);
+ perf_install_in_context(ctx, event, cpu);
+ ++ctx->generation;
+ mutex_unlock(&ctx->mutex);
+
+ event->owner = current;
+ get_task_struct(current);
+ mutex_lock(&current->perf_event_mutex);
+ list_add_tail(&event->owner_entry, &current->perf_event_list);
+ mutex_unlock(&current->perf_event_mutex);
+
+ return event;
+
+ err_put_context:
+ put_ctx(ctx);
+ err_exit:
+ return ERR_PTR(err);
+}
+EXPORT_SYMBOL_GPL(perf_event_create_kernel_counter);
+
+/*
+ * inherit a event from parent task to child task:
+ */
+static struct perf_event *
+inherit_event(struct perf_event *parent_event,
+ struct task_struct *parent,
+ struct perf_event_context *parent_ctx,
+ struct task_struct *child,
+ struct perf_event *group_leader,
+ struct perf_event_context *child_ctx)
+{
+ struct perf_event *child_event;
+
+ /*
+ * Instead of creating recursive hierarchies of events,
+ * we link inherited events back to the original parent,
+ * which has a filp for sure, which we use as the reference
+ * count:
+ */
+ if (parent_event->parent)
+ parent_event = parent_event->parent;
+
+ child_event = perf_event_alloc(&parent_event->attr,
+ parent_event->cpu, child_ctx,
+ group_leader, parent_event,
+ NULL, GFP_KERNEL);
+ if (IS_ERR(child_event))
+ return child_event;
+ get_ctx(child_ctx);
+
+ /*
+ * Make the child state follow the state of the parent event,
+ * not its attr.disabled bit. We hold the parent's mutex,
+ * so we won't race with perf_event_{en, dis}able_family.
+ */
+ if (parent_event->state >= PERF_EVENT_STATE_INACTIVE)
+ child_event->state = PERF_EVENT_STATE_INACTIVE;
+ else
+ child_event->state = PERF_EVENT_STATE_OFF;
+
+ if (parent_event->attr.freq) {
+ u64 sample_period = parent_event->hw.sample_period;
+ struct hw_perf_event *hwc = &child_event->hw;
+
+ hwc->sample_period = sample_period;
+ hwc->last_period = sample_period;
+
+ local64_set(&hwc->period_left, sample_period);
+ }
+
+ child_event->overflow_handler = parent_event->overflow_handler;
+
+ /*
+ * Link it up in the child's context:
+ */
+ add_event_to_ctx(child_event, child_ctx);
+
+ /*
+ * Get a reference to the parent filp - we will fput it
+ * when the child event exits. This is safe to do because
+ * we are in the parent and we know that the filp still
+ * exists and has a nonzero count:
+ */
+ atomic_long_inc(&parent_event->filp->f_count);
+
+ /*
+ * Link this into the parent event's child list
+ */
+ WARN_ON_ONCE(parent_event->ctx->parent_ctx);
+ mutex_lock(&parent_event->child_mutex);
+ list_add_tail(&child_event->child_list, &parent_event->child_list);
+ mutex_unlock(&parent_event->child_mutex);
+
+ return child_event;
+}
+
+static int inherit_group(struct perf_event *parent_event,
+ struct task_struct *parent,
+ struct perf_event_context *parent_ctx,
+ struct task_struct *child,
+ struct perf_event_context *child_ctx)
+{
+ struct perf_event *leader;
+ struct perf_event *sub;
+ struct perf_event *child_ctr;
+
+ leader = inherit_event(parent_event, parent, parent_ctx,
+ child, NULL, child_ctx);
+ if (IS_ERR(leader))
+ return PTR_ERR(leader);
+ list_for_each_entry(sub, &parent_event->sibling_list, group_entry) {
+ child_ctr = inherit_event(sub, parent, parent_ctx,
+ child, leader, child_ctx);
+ if (IS_ERR(child_ctr))
+ return PTR_ERR(child_ctr);
+ }
+ return 0;
+}
+
+static void sync_child_event(struct perf_event *child_event,
+ struct task_struct *child)
+{
+ struct perf_event *parent_event = child_event->parent;
+ u64 child_val;
+
+ if (child_event->attr.inherit_stat)
+ perf_event_read_event(child_event, child);
+
+ child_val = perf_event_count(child_event);
+
+ /*
+ * Add back the child's count to the parent's count:
+ */
+ atomic64_add(child_val, &parent_event->child_count);
+ atomic64_add(child_event->total_time_enabled,
+ &parent_event->child_total_time_enabled);
+ atomic64_add(child_event->total_time_running,
+ &parent_event->child_total_time_running);
+
+ /*
+ * Remove this event from the parent's list
+ */
+ WARN_ON_ONCE(parent_event->ctx->parent_ctx);
+ mutex_lock(&parent_event->child_mutex);
+ list_del_init(&child_event->child_list);
+ mutex_unlock(&parent_event->child_mutex);
+
+ /*
+ * Release the parent event, if this was the last
+ * reference to it.
+ */
+ fput(parent_event->filp);
+}
+
+static void
+__perf_event_exit_task(struct perf_event *child_event,
+ struct perf_event_context *child_ctx,
+ struct task_struct *child)
+{
+ struct perf_event *parent_event;
+
+ perf_event_remove_from_context(child_event);
+
+ parent_event = child_event->parent;
+ /*
+ * It can happen that parent exits first, and has events
+ * that are still around due to the child reference. These
+ * events need to be zapped - but otherwise linger.
+ */
+ if (parent_event) {
+ sync_child_event(child_event, child);
+ free_event(child_event);
+ }
+}
+
+/*
+ * When a child task exits, feed back event values to parent events.
+ */
+void perf_event_exit_task(struct task_struct *child)
+{
+ struct perf_event *child_event, *tmp;
+ struct perf_event_context *child_ctx;
+ unsigned long flags;
+
+ if (likely(!child->perf_event_ctxp)) {
+ perf_event_task(child, NULL, 0);
+ return;
+ }
+
+ local_irq_save(flags);
+ /*
+ * We can't reschedule here because interrupts are disabled,
+ * and either child is current or it is a task that can't be
+ * scheduled, so we are now safe from rescheduling changing
+ * our context.
+ */
+ child_ctx = child->perf_event_ctxp;
+ __perf_event_task_sched_out(child_ctx);
+
+ /*
+ * Take the context lock here so that if find_get_context is
+ * reading child->perf_event_ctxp, we wait until it has
+ * incremented the context's refcount before we do put_ctx below.
+ */
+ raw_spin_lock(&child_ctx->lock);
+ child->perf_event_ctxp = NULL;
+ /*
+ * If this context is a clone; unclone it so it can't get
+ * swapped to another process while we're removing all
+ * the events from it.
+ */
+ unclone_ctx(child_ctx);
+ update_context_time(child_ctx);
+ raw_spin_unlock_irqrestore(&child_ctx->lock, flags);
+
+ /*
+ * Report the task dead after unscheduling the events so that we
+ * won't get any samples after PERF_RECORD_EXIT. We can however still
+ * get a few PERF_RECORD_READ events.
+ */
+ perf_event_task(child, child_ctx, 0);
+
+ /*
+ * We can recurse on the same lock type through:
+ *
+ * __perf_event_exit_task()
+ * sync_child_event()
+ * fput(parent_event->filp)
+ * perf_release()
+ * mutex_lock(&ctx->mutex)
+ *
+ * But since its the parent context it won't be the same instance.
+ */
+ mutex_lock(&child_ctx->mutex);
+
+again:
+ list_for_each_entry_safe(child_event, tmp, &child_ctx->pinned_groups,
+ group_entry)
+ __perf_event_exit_task(child_event, child_ctx, child);
+
+ list_for_each_entry_safe(child_event, tmp, &child_ctx->flexible_groups,
+ group_entry)
+ __perf_event_exit_task(child_event, child_ctx, child);
+
+ /*
+ * If the last event was a group event, it will have appended all
+ * its siblings to the list, but we obtained 'tmp' before that which
+ * will still point to the list head terminating the iteration.
+ */
+ if (!list_empty(&child_ctx->pinned_groups) ||
+ !list_empty(&child_ctx->flexible_groups))
+ goto again;
+
+ mutex_unlock(&child_ctx->mutex);
+
+ put_ctx(child_ctx);
+}
+
+static void perf_free_event(struct perf_event *event,
+ struct perf_event_context *ctx)
+{
+ struct perf_event *parent = event->parent;
+
+ if (WARN_ON_ONCE(!parent))
+ return;
+
+ mutex_lock(&parent->child_mutex);
+ list_del_init(&event->child_list);
+ mutex_unlock(&parent->child_mutex);
+
+ fput(parent->filp);
+
+ perf_group_detach(event);
+ list_del_event(event, ctx);
+ free_event(event);
+}
+
+/*
+ * free an unexposed, unused context as created by inheritance by
+ * init_task below, used by fork() in case of fail.
+ */
+void perf_event_free_task(struct task_struct *task)
+{
+ struct perf_event_context *ctx = task->perf_event_ctxp;
+ struct perf_event *event, *tmp;
+
+ if (!ctx)
+ return;
+
+ mutex_lock(&ctx->mutex);
+again:
+ list_for_each_entry_safe(event, tmp, &ctx->pinned_groups, group_entry)
+ perf_free_event(event, ctx);
+
+ list_for_each_entry_safe(event, tmp, &ctx->flexible_groups,
+ group_entry)
+ perf_free_event(event, ctx);
+
+ if (!list_empty(&ctx->pinned_groups) ||
+ !list_empty(&ctx->flexible_groups))
+ goto again;
+
+ mutex_unlock(&ctx->mutex);
+
+ put_ctx(ctx);
+}
+
+static int
+inherit_task_group(struct perf_event *event, struct task_struct *parent,
+ struct perf_event_context *parent_ctx,
+ struct task_struct *child,
+ int *inherited_all)
+{
+ int ret;
+ struct perf_event_context *child_ctx = child->perf_event_ctxp;
+
+ if (!event->attr.inherit) {
+ *inherited_all = 0;
+ return 0;
+ }
+
+ if (!child_ctx) {
+ /*
+ * This is executed from the parent task context, so
+ * inherit events that have been marked for cloning.
+ * First allocate and initialize a context for the
+ * child.
+ */
+
+ child_ctx = kzalloc(sizeof(struct perf_event_context),
+ GFP_KERNEL);
+ if (!child_ctx)
+ return -ENOMEM;
+
+ __perf_event_init_context(child_ctx, child);
+ child->perf_event_ctxp = child_ctx;
+ get_task_struct(child);
+ }
+
+ ret = inherit_group(event, parent, parent_ctx,
+ child, child_ctx);
+
+ if (ret)
+ *inherited_all = 0;
+
+ return ret;
+}
+
+
+/*
+ * Initialize the perf_event context in task_struct
+ */
+int perf_event_init_task(struct task_struct *child)
+{
+ struct perf_event_context *child_ctx, *parent_ctx;
+ struct perf_event_context *cloned_ctx;
+ struct perf_event *event;
+ struct task_struct *parent = current;
+ int inherited_all = 1;
+ int ret = 0;
+
+ child->perf_event_ctxp = NULL;
+
+ mutex_init(&child->perf_event_mutex);
+ INIT_LIST_HEAD(&child->perf_event_list);
+
+ if (likely(!parent->perf_event_ctxp))
+ return 0;
+
+ /*
+ * If the parent's context is a clone, pin it so it won't get
+ * swapped under us.
+ */
+ parent_ctx = perf_pin_task_context(parent);
+
+ /*
+ * No need to check if parent_ctx != NULL here; since we saw
+ * it non-NULL earlier, the only reason for it to become NULL
+ * is if we exit, and since we're currently in the middle of
+ * a fork we can't be exiting at the same time.
+ */
+
+ /*
+ * Lock the parent list. No need to lock the child - not PID
+ * hashed yet and not running, so nobody can access it.
+ */
+ mutex_lock(&parent_ctx->mutex);
+
+ /*
+ * We dont have to disable NMIs - we are only looking at
+ * the list, not manipulating it:
+ */
+ list_for_each_entry(event, &parent_ctx->pinned_groups, group_entry) {
+ ret = inherit_task_group(event, parent, parent_ctx, child,
+ &inherited_all);
+ if (ret)
+ break;
+ }
+
+ list_for_each_entry(event, &parent_ctx->flexible_groups, group_entry) {
+ ret = inherit_task_group(event, parent, parent_ctx, child,
+ &inherited_all);
+ if (ret)
+ break;
+ }
+
+ child_ctx = child->perf_event_ctxp;
+
+ if (child_ctx && inherited_all) {
+ /*
+ * Mark the child context as a clone of the parent
+ * context, or of whatever the parent is a clone of.
+ * Note that if the parent is a clone, it could get
+ * uncloned at any point, but that doesn't matter
+ * because the list of events and the generation
+ * count can't have changed since we took the mutex.
+ */
+ cloned_ctx = rcu_dereference(parent_ctx->parent_ctx);
+ if (cloned_ctx) {
+ child_ctx->parent_ctx = cloned_ctx;
+ child_ctx->parent_gen = parent_ctx->parent_gen;
+ } else {
+ child_ctx->parent_ctx = parent_ctx;
+ child_ctx->parent_gen = parent_ctx->generation;
+ }
+ get_ctx(child_ctx->parent_ctx);
+ }
+
+ mutex_unlock(&parent_ctx->mutex);
+
+ perf_unpin_context(parent_ctx);
+
+ return ret;
+}
+
+static void __init perf_event_init_all_cpus(void)
+{
+ int cpu;
+ struct perf_cpu_context *cpuctx;
+
+ for_each_possible_cpu(cpu) {
+ cpuctx = &per_cpu(perf_cpu_context, cpu);
+ mutex_init(&cpuctx->hlist_mutex);
+ __perf_event_init_context(&cpuctx->ctx, NULL);
+ }
+}
+
+static void __cpuinit perf_event_init_cpu(int cpu)
+{
+ struct perf_cpu_context *cpuctx;
+
+ cpuctx = &per_cpu(perf_cpu_context, cpu);
+
+ spin_lock(&perf_resource_lock);
+ cpuctx->max_pertask = perf_max_events - perf_reserved_percpu;
+ spin_unlock(&perf_resource_lock);
+
+ mutex_lock(&cpuctx->hlist_mutex);
+ if (cpuctx->hlist_refcount > 0) {
+ struct swevent_hlist *hlist;
+
+ hlist = kzalloc(sizeof(*hlist), GFP_KERNEL);
+ WARN_ON_ONCE(!hlist);
+ rcu_assign_pointer(cpuctx->swevent_hlist, hlist);
+ }
+ mutex_unlock(&cpuctx->hlist_mutex);
+}
+
+#ifdef CONFIG_HOTPLUG_CPU
+static void __perf_event_exit_cpu(void *info)
+{
+ struct perf_cpu_context *cpuctx = &__get_cpu_var(perf_cpu_context);
+ struct perf_event_context *ctx = &cpuctx->ctx;
+ struct perf_event *event, *tmp;
+
+ list_for_each_entry_safe(event, tmp, &ctx->pinned_groups, group_entry)
+ __perf_event_remove_from_context(event);
+ list_for_each_entry_safe(event, tmp, &ctx->flexible_groups, group_entry)
+ __perf_event_remove_from_context(event);
+}
+static void perf_event_exit_cpu(int cpu)
+{
+ struct perf_cpu_context *cpuctx = &per_cpu(perf_cpu_context, cpu);
+ struct perf_event_context *ctx = &cpuctx->ctx;
+
+ mutex_lock(&cpuctx->hlist_mutex);
+ swevent_hlist_release(cpuctx);
+ mutex_unlock(&cpuctx->hlist_mutex);
+
+ mutex_lock(&ctx->mutex);
+ smp_call_function_single(cpu, __perf_event_exit_cpu, NULL, 1);
+ mutex_unlock(&ctx->mutex);
+}
+#else
+static inline void perf_event_exit_cpu(int cpu) { }
+#endif
+
+static int __cpuinit
+perf_cpu_notify(struct notifier_block *self, unsigned long action, void *hcpu)
+{
+ unsigned int cpu = (long)hcpu;
+
+ switch (action & ~CPU_TASKS_FROZEN) {
+
+ case CPU_UP_PREPARE:
+ case CPU_DOWN_FAILED:
+ perf_event_init_cpu(cpu);
+ break;
+
+ case CPU_UP_CANCELED:
+ case CPU_DOWN_PREPARE:
+ perf_event_exit_cpu(cpu);
+ break;
+
+ default:
+ break;
+ }
+
+ return NOTIFY_OK;
+}
+
+/*
+ * This has to have a higher priority than migration_notifier in sched.c.
+ */
+static struct notifier_block __cpuinitdata perf_cpu_nb = {
+ .notifier_call = perf_cpu_notify,
+ .priority = 20,
+};
+
+void __init perf_event_init(void)
+{
+ perf_event_init_all_cpus();
+ perf_cpu_notify(&perf_cpu_nb, (unsigned long)CPU_UP_PREPARE,
+ (void *)(long)smp_processor_id());
+ perf_cpu_notify(&perf_cpu_nb, (unsigned long)CPU_ONLINE,
+ (void *)(long)smp_processor_id());
+ register_cpu_notifier(&perf_cpu_nb);
+}
+
+static ssize_t perf_show_reserve_percpu(struct sysdev_class *class,
+ struct sysdev_class_attribute *attr,
+ char *buf)
+{
+ return sprintf(buf, "%d\n", perf_reserved_percpu);
+}
+
+static ssize_t
+perf_set_reserve_percpu(struct sysdev_class *class,
+ struct sysdev_class_attribute *attr,
+ const char *buf,
+ size_t count)
+{
+ struct perf_cpu_context *cpuctx;
+ unsigned long val;
+ int err, cpu, mpt;
+
+ err = strict_strtoul(buf, 10, &val);
+ if (err)
+ return err;
+ if (val > perf_max_events)
+ return -EINVAL;
+
+ spin_lock(&perf_resource_lock);
+ perf_reserved_percpu = val;
+ for_each_online_cpu(cpu) {
+ cpuctx = &per_cpu(perf_cpu_context, cpu);
+ raw_spin_lock_irq(&cpuctx->ctx.lock);
+ mpt = min(perf_max_events - cpuctx->ctx.nr_events,
+ perf_max_events - perf_reserved_percpu);
+ cpuctx->max_pertask = mpt;
+ raw_spin_unlock_irq(&cpuctx->ctx.lock);
+ }
+ spin_unlock(&perf_resource_lock);
+
+ return count;
+}
+
+static ssize_t perf_show_overcommit(struct sysdev_class *class,
+ struct sysdev_class_attribute *attr,
+ char *buf)
+{
+ return sprintf(buf, "%d\n", perf_overcommit);
+}
+
+static ssize_t
+perf_set_overcommit(struct sysdev_class *class,
+ struct sysdev_class_attribute *attr,
+ const char *buf, size_t count)
+{
+ unsigned long val;
+ int err;
+
+ err = strict_strtoul(buf, 10, &val);
+ if (err)
+ return err;
+ if (val > 1)
+ return -EINVAL;
+
+ spin_lock(&perf_resource_lock);
+ perf_overcommit = val;
+ spin_unlock(&perf_resource_lock);
+
+ return count;
+}
+
+static SYSDEV_CLASS_ATTR(
+ reserve_percpu,
+ 0644,
+ perf_show_reserve_percpu,
+ perf_set_reserve_percpu
+ );
+
+static SYSDEV_CLASS_ATTR(
+ overcommit,
+ 0644,
+ perf_show_overcommit,
+ perf_set_overcommit
+ );
+
+static struct attribute *perfclass_attrs[] = {
+ &attr_reserve_percpu.attr,
+ &attr_overcommit.attr,
+ NULL
+};
+
+static struct attribute_group perfclass_attr_group = {
+ .attrs = perfclass_attrs,
+ .name = "perf_events",
+};
+
+static int __init perf_event_sysfs_init(void)
+{
+ return sysfs_create_group(&cpu_sysdev_class.kset.kobj,
+ &perfclass_attr_group);
+}
+device_initcall(perf_event_sysfs_init);
diff --git a/kernel/perf_event.c b/kernel/perf_event.c
deleted file mode 100644
index b98bed3..0000000
--- a/kernel/perf_event.c
+++ /dev/null
@@ -1,5895 +0,0 @@
-/*
- * 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/slab.h>
-#include <linux/hash.h>
-#include <linux/sysfs.h>
-#include <linux/dcache.h>
-#include <linux/percpu.h>
-#include <linux/ptrace.h>
-#include <linux/vmstat.h>
-#include <linux/vmalloc.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 <linux/ftrace_event.h>
-#include <linux/hw_breakpoint.h>
-
-#include <asm/irq_regs.h>
-
-/*
- * Each CPU has a list of per CPU events:
- */
-static DEFINE_PER_CPU(struct perf_cpu_context, perf_cpu_context);
-
-int perf_max_events __read_mostly = 1;
-static int perf_reserved_percpu __read_mostly;
-static int perf_overcommit __read_mostly = 1;
-
-static atomic_t nr_events __read_mostly;
-static atomic_t nr_mmap_events __read_mostly;
-static atomic_t nr_comm_events __read_mostly;
-static atomic_t nr_task_events __read_mostly;
-
-/*
- * perf event paranoia level:
- * -1 - not paranoid at all
- * 0 - disallow raw tracepoint access for unpriv
- * 1 - disallow cpu events for unpriv
- * 2 - disallow kernel profiling for unpriv
- */
-int sysctl_perf_event_paranoid __read_mostly = 1;
-
-int sysctl_perf_event_mlock __read_mostly = 512; /* 'free' kb per user */
-
-/*
- * max perf event sample rate
- */
-int sysctl_perf_event_sample_rate __read_mostly = 100000;
-
-static atomic64_t perf_event_id;
-
-/*
- * Lock for (sysadmin-configurable) event reservations:
- */
-static DEFINE_SPINLOCK(perf_resource_lock);
-
-/*
- * Architecture provided APIs - weak aliases:
- */
-extern __weak const struct pmu *hw_perf_event_init(struct perf_event *event)
-{
- return NULL;
-}
-
-void __weak hw_perf_disable(void) { barrier(); }
-void __weak hw_perf_enable(void) { barrier(); }
-
-void __weak perf_event_print_debug(void) { }
-
-static DEFINE_PER_CPU(int, perf_disable_count);
-
-void perf_disable(void)
-{
- if (!__get_cpu_var(perf_disable_count)++)
- hw_perf_disable();
-}
-
-void perf_enable(void)
-{
- if (!--__get_cpu_var(perf_disable_count))
- hw_perf_enable();
-}
-
-static void get_ctx(struct perf_event_context *ctx)
-{
- WARN_ON(!atomic_inc_not_zero(&ctx->refcount));
-}
-
-static void free_ctx(struct rcu_head *head)
-{
- struct perf_event_context *ctx;
-
- ctx = container_of(head, struct perf_event_context, rcu_head);
- kfree(ctx);
-}
-
-static void put_ctx(struct perf_event_context *ctx)
-{
- if (atomic_dec_and_test(&ctx->refcount)) {
- if (ctx->parent_ctx)
- put_ctx(ctx->parent_ctx);
- if (ctx->task)
- put_task_struct(ctx->task);
- call_rcu(&ctx->rcu_head, free_ctx);
- }
-}
-
-static void unclone_ctx(struct perf_event_context *ctx)
-{
- if (ctx->parent_ctx) {
- put_ctx(ctx->parent_ctx);
- ctx->parent_ctx = NULL;
- }
-}
-
-/*
- * If we inherit events we want to return the parent event id
- * to userspace.
- */
-static u64 primary_event_id(struct perf_event *event)
-{
- u64 id = event->id;
-
- if (event->parent)
- id = event->parent->id;
-
- return id;
-}
-
-/*
- * Get the perf_event_context for a task and lock it.
- * This has to cope with with the fact that until it is locked,
- * the context could get moved to another task.
- */
-static struct perf_event_context *
-perf_lock_task_context(struct task_struct *task, unsigned long *flags)
-{
- struct perf_event_context *ctx;
-
- rcu_read_lock();
- retry:
- ctx = rcu_dereference(task->perf_event_ctxp);
- if (ctx) {
- /*
- * If this context is a clone of another, it might
- * get swapped for another underneath us by
- * perf_event_task_sched_out, though the
- * rcu_read_lock() protects us from any context
- * getting freed. Lock the context and check if it
- * got swapped before we could get the lock, and retry
- * if so. If we locked the right context, then it
- * can't get swapped on us any more.
- */
- raw_spin_lock_irqsave(&ctx->lock, *flags);
- if (ctx != rcu_dereference(task->perf_event_ctxp)) {
- raw_spin_unlock_irqrestore(&ctx->lock, *flags);
- goto retry;
- }
-
- if (!atomic_inc_not_zero(&ctx->refcount)) {
- raw_spin_unlock_irqrestore(&ctx->lock, *flags);
- ctx = NULL;
- }
- }
- rcu_read_unlock();
- return ctx;
-}
-
-/*
- * Get the context for a task and increment its pin_count so it
- * can't get swapped to another task. This also increments its
- * reference count so that the context can't get freed.
- */
-static struct perf_event_context *perf_pin_task_context(struct task_struct *task)
-{
- struct perf_event_context *ctx;
- unsigned long flags;
-
- ctx = perf_lock_task_context(task, &flags);
- if (ctx) {
- ++ctx->pin_count;
- raw_spin_unlock_irqrestore(&ctx->lock, flags);
- }
- return ctx;
-}
-
-static void perf_unpin_context(struct perf_event_context *ctx)
-{
- unsigned long flags;
-
- raw_spin_lock_irqsave(&ctx->lock, flags);
- --ctx->pin_count;
- raw_spin_unlock_irqrestore(&ctx->lock, flags);
- put_ctx(ctx);
-}
-
-static inline u64 perf_clock(void)
-{
- return local_clock();
-}
-
-/*
- * Update the record of the current time in a context.
- */
-static void update_context_time(struct perf_event_context *ctx)
-{
- u64 now = perf_clock();
-
- ctx->time += now - ctx->timestamp;
- ctx->timestamp = now;
-}
-
-/*
- * Update the total_time_enabled and total_time_running fields for a event.
- */
-static void update_event_times(struct perf_event *event)
-{
- struct perf_event_context *ctx = event->ctx;
- u64 run_end;
-
- if (event->state < PERF_EVENT_STATE_INACTIVE ||
- event->group_leader->state < PERF_EVENT_STATE_INACTIVE)
- return;
-
- if (ctx->is_active)
- run_end = ctx->time;
- else
- run_end = event->tstamp_stopped;
-
- event->total_time_enabled = run_end - event->tstamp_enabled;
-
- if (event->state == PERF_EVENT_STATE_INACTIVE)
- run_end = event->tstamp_stopped;
- else
- run_end = ctx->time;
-
- event->total_time_running = run_end - event->tstamp_running;
-}
-
-/*
- * Update total_time_enabled and total_time_running for all events in a group.
- */
-static void update_group_times(struct perf_event *leader)
-{
- struct perf_event *event;
-
- update_event_times(leader);
- list_for_each_entry(event, &leader->sibling_list, group_entry)
- update_event_times(event);
-}
-
-static struct list_head *
-ctx_group_list(struct perf_event *event, struct perf_event_context *ctx)
-{
- if (event->attr.pinned)
- return &ctx->pinned_groups;
- else
- return &ctx->flexible_groups;
-}
-
-/*
- * Add a event from the lists for its context.
- * Must be called with ctx->mutex and ctx->lock held.
- */
-static void
-list_add_event(struct perf_event *event, struct perf_event_context *ctx)
-{
- WARN_ON_ONCE(event->attach_state & PERF_ATTACH_CONTEXT);
- event->attach_state |= PERF_ATTACH_CONTEXT;
-
- /*
- * If we're a stand alone event or group leader, we go to the context
- * list, group events are kept attached to the group so that
- * perf_group_detach can, at all times, locate all siblings.
- */
- if (event->group_leader == event) {
- struct list_head *list;
-
- if (is_software_event(event))
- event->group_flags |= PERF_GROUP_SOFTWARE;
-
- list = ctx_group_list(event, ctx);
- list_add_tail(&event->group_entry, list);
- }
-
- list_add_rcu(&event->event_entry, &ctx->event_list);
- ctx->nr_events++;
- if (event->attr.inherit_stat)
- ctx->nr_stat++;
-}
-
-static void perf_group_attach(struct perf_event *event)
-{
- struct perf_event *group_leader = event->group_leader;
-
- WARN_ON_ONCE(event->attach_state & PERF_ATTACH_GROUP);
- event->attach_state |= PERF_ATTACH_GROUP;
-
- if (group_leader == event)
- return;
-
- if (group_leader->group_flags & PERF_GROUP_SOFTWARE &&
- !is_software_event(event))
- group_leader->group_flags &= ~PERF_GROUP_SOFTWARE;
-
- list_add_tail(&event->group_entry, &group_leader->sibling_list);
- group_leader->nr_siblings++;
-}
-
-/*
- * Remove a event from the lists for its context.
- * Must be called with ctx->mutex and ctx->lock held.
- */
-static void
-list_del_event(struct perf_event *event, struct perf_event_context *ctx)
-{
- /*
- * We can have double detach due to exit/hot-unplug + close.
- */
- if (!(event->attach_state & PERF_ATTACH_CONTEXT))
- return;
-
- event->attach_state &= ~PERF_ATTACH_CONTEXT;
-
- ctx->nr_events--;
- if (event->attr.inherit_stat)
- ctx->nr_stat--;
-
- list_del_rcu(&event->event_entry);
-
- if (event->group_leader == event)
- list_del_init(&event->group_entry);
-
- update_group_times(event);
-
- /*
- * If event was in error state, then keep it
- * that way, otherwise bogus counts will be
- * returned on read(). The only way to get out
- * of error state is by explicit re-enabling
- * of the event
- */
- if (event->state > PERF_EVENT_STATE_OFF)
- event->state = PERF_EVENT_STATE_OFF;
-}
-
-static void perf_group_detach(struct perf_event *event)
-{
- struct perf_event *sibling, *tmp;
- struct list_head *list = NULL;
-
- /*
- * We can have double detach due to exit/hot-unplug + close.
- */
- if (!(event->attach_state & PERF_ATTACH_GROUP))
- return;
-
- event->attach_state &= ~PERF_ATTACH_GROUP;
-
- /*
- * If this is a sibling, remove it from its group.
- */
- if (event->group_leader != event) {
- list_del_init(&event->group_entry);
- event->group_leader->nr_siblings--;
- return;
- }
-
- if (!list_empty(&event->group_entry))
- list = &event->group_entry;
-
- /*
- * If this was a group event with sibling events then
- * upgrade the siblings to singleton events by adding them
- * to whatever list we are on.
- */
- list_for_each_entry_safe(sibling, tmp, &event->sibling_list, group_entry) {
- if (list)
- list_move_tail(&sibling->group_entry, list);
- sibling->group_leader = sibling;
-
- /* Inherit group flags from the previous leader */
- sibling->group_flags = event->group_flags;
- }
-}
-
-static inline int
-event_filter_match(struct perf_event *event)
-{
- return event->cpu == -1 || event->cpu == smp_processor_id();
-}
-
-static void
-event_sched_out(struct perf_event *event,
- struct perf_cpu_context *cpuctx,
- struct perf_event_context *ctx)
-{
- u64 delta;
- /*
- * An event which could not be activated because of
- * filter mismatch still needs to have its timings
- * maintained, otherwise bogus information is return
- * via read() for time_enabled, time_running:
- */
- if (event->state == PERF_EVENT_STATE_INACTIVE
- && !event_filter_match(event)) {
- delta = ctx->time - event->tstamp_stopped;
- event->tstamp_running += delta;
- event->tstamp_stopped = ctx->time;
- }
-
- 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;
- int state = group_event->state;
-
- event_sched_out(group_event, cpuctx, ctx);
-
- /*
- * Schedule out siblings (if any):
- */
- list_for_each_entry(event, &group_event->sibling_list, group_entry)
- event_sched_out(event, cpuctx, ctx);
-
- if (state == PERF_EVENT_STATE_ACTIVE && group_event->attr.exclusive)
- cpuctx->exclusive = 0;
-}
-
-/*
- * Cross CPU call to remove a performance event
- *
- * We disable the event on the hardware level first. After that we
- * remove it from the context list.
- */
-static void __perf_event_remove_from_context(void *info)
-{
- struct perf_cpu_context *cpuctx = &__get_cpu_var(perf_cpu_context);
- struct perf_event *event = info;
- struct perf_event_context *ctx = event->ctx;
-
- /*
- * If this is a task context, we need to check whether it is
- * the current task context of this cpu. If not it has been
- * scheduled out before the smp call arrived.
- */
- if (ctx->task && cpuctx->task_ctx != ctx)
- return;
-
- raw_spin_lock(&ctx->lock);
- /*
- * Protect the list operation against NMI by disabling the
- * events on a global level.
- */
- perf_disable();
-
- event_sched_out(event, cpuctx, ctx);
-
- list_del_event(event, ctx);
-
- if (!ctx->task) {
- /*
- * Allow more per task events with respect to the
- * reservation:
- */
- cpuctx->max_pertask =
- min(perf_max_events - ctx->nr_events,
- perf_max_events - perf_reserved_percpu);
- }
-
- perf_enable();
- raw_spin_unlock(&ctx->lock);
-}
-
-
-/*
- * Remove the event from a task's (or a CPU's) list of events.
- *
- * Must be called with ctx->mutex held.
- *
- * CPU events are removed with a smp call. For task events we only
- * call when the task is on a CPU.
- *
- * If event->ctx is a cloned context, callers must make sure that
- * every task struct that event->ctx->task could possibly point to
- * remains valid. This is OK when called from perf_release since
- * that only calls us on the top-level context, which can't be a clone.
- * When called from perf_event_exit_task, it's OK because the
- * context has been detached from its task.
- */
-static void perf_event_remove_from_context(struct perf_event *event)
-{
- struct perf_event_context *ctx = event->ctx;
- struct task_struct *task = ctx->task;
-
- if (!task) {
- /*
- * Per cpu events are removed via an smp call and
- * the removal is always successful.
- */
- smp_call_function_single(event->cpu,
- __perf_event_remove_from_context,
- event, 1);
- return;
- }
-
-retry:
- task_oncpu_function_call(task, __perf_event_remove_from_context,
- event);
-
- raw_spin_lock_irq(&ctx->lock);
- /*
- * If the context is active we need to retry the smp call.
- */
- if (ctx->nr_active && !list_empty(&event->group_entry)) {
- raw_spin_unlock_irq(&ctx->lock);
- goto retry;
- }
-
- /*
- * The lock prevents that this context is scheduled in so we
- * can remove the event safely, if the call above did not
- * succeed.
- */
- if (!list_empty(&event->group_entry))
- list_del_event(event, ctx);
- raw_spin_unlock_irq(&ctx->lock);
-}
-
-/*
- * Cross CPU call to disable a performance event
- */
-static void __perf_event_disable(void *info)
-{
- struct perf_event *event = info;
- struct perf_cpu_context *cpuctx = &__get_cpu_var(perf_cpu_context);
- struct perf_event_context *ctx = event->ctx;
-
- /*
- * If this is a per-task event, need to check whether this
- * event's task is the current task on this cpu.
- */
- if (ctx->task && cpuctx->task_ctx != ctx)
- return;
-
- raw_spin_lock(&ctx->lock);
-
- /*
- * If the event is on, turn it off.
- * If it is in error state, leave it in error state.
- */
- if (event->state >= PERF_EVENT_STATE_INACTIVE) {
- update_context_time(ctx);
- update_group_times(event);
- if (event == event->group_leader)
- group_sched_out(event, cpuctx, ctx);
- else
- event_sched_out(event, cpuctx, ctx);
- event->state = PERF_EVENT_STATE_OFF;
- }
-
- raw_spin_unlock(&ctx->lock);
-}
-
-/*
- * Disable a event.
- *
- * If event->ctx is a cloned context, callers must make sure that
- * every task struct that event->ctx->task could possibly point to
- * remains valid. This condition is satisifed when called through
- * perf_event_for_each_child or perf_event_for_each because they
- * hold the top-level event's child_mutex, so any descendant that
- * goes to exit will block in sync_child_event.
- * When called from perf_pending_event it's OK because event->ctx
- * is the current context on this CPU and preemption is disabled,
- * hence we can't get into perf_event_task_sched_out for this context.
- */
-void perf_event_disable(struct perf_event *event)
-{
- struct perf_event_context *ctx = event->ctx;
- struct task_struct *task = ctx->task;
-
- if (!task) {
- /*
- * Disable the event on the cpu that it's on
- */
- smp_call_function_single(event->cpu, __perf_event_disable,
- event, 1);
- return;
- }
-
- retry:
- task_oncpu_function_call(task, __perf_event_disable, event);
-
- raw_spin_lock_irq(&ctx->lock);
- /*
- * If the event is still active, we need to retry the cross-call.
- */
- if (event->state == PERF_EVENT_STATE_ACTIVE) {
- raw_spin_unlock_irq(&ctx->lock);
- goto retry;
- }
-
- /*
- * Since we have the lock this context can't be scheduled
- * in, so we can change the state safely.
- */
- if (event->state == PERF_EVENT_STATE_INACTIVE) {
- update_group_times(event);
- event->state = PERF_EVENT_STATE_OFF;
- }
-
- raw_spin_unlock_irq(&ctx->lock);
-}
-
-static int
-event_sched_in(struct perf_event *event,
- struct perf_cpu_context *cpuctx,
- struct perf_event_context *ctx)
-{
- if (event->state <= PERF_EVENT_STATE_OFF)
- return 0;
-
- event->state = PERF_EVENT_STATE_ACTIVE;
- event->oncpu = smp_processor_id();
- /*
- * The new state must be visible before we turn it on in the hardware:
- */
- smp_wmb();
-
- if (event->pmu->enable(event)) {
- event->state = PERF_EVENT_STATE_INACTIVE;
- event->oncpu = -1;
- return -EAGAIN;
- }
-
- event->tstamp_running += ctx->time - event->tstamp_stopped;
-
- if (!is_software_event(event))
- cpuctx->active_oncpu++;
- ctx->nr_active++;
-
- if (event->attr.exclusive)
- cpuctx->exclusive = 1;
-
- return 0;
-}
-
-static int
-group_sched_in(struct perf_event *group_event,
- struct perf_cpu_context *cpuctx,
- struct perf_event_context *ctx)
-{
- struct perf_event *event, *partial_group = NULL;
- const struct pmu *pmu = group_event->pmu;
- bool txn = false;
-
- if (group_event->state == PERF_EVENT_STATE_OFF)
- return 0;
-
- /* Check if group transaction availabe */
- if (pmu->start_txn)
- txn = true;
-
- if (txn)
- pmu->start_txn(pmu);
-
- if (event_sched_in(group_event, cpuctx, ctx)) {
- if (txn)
- pmu->cancel_txn(pmu);
- return -EAGAIN;
- }
-
- /*
- * Schedule in siblings as one group (if any):
- */
- list_for_each_entry(event, &group_event->sibling_list, group_entry) {
- if (event_sched_in(event, cpuctx, ctx)) {
- partial_group = event;
- goto group_error;
- }
- }
-
- if (!txn || !pmu->commit_txn(pmu))
- return 0;
-
-group_error:
- /*
- * Groups can be scheduled in as one unit only, so undo any
- * partial group before returning:
- */
- list_for_each_entry(event, &group_event->sibling_list, group_entry) {
- if (event == partial_group)
- break;
- event_sched_out(event, cpuctx, ctx);
- }
- event_sched_out(group_event, cpuctx, ctx);
-
- if (txn)
- pmu->cancel_txn(pmu);
-
- return -EAGAIN;
-}
-
-/*
- * Work out whether we can put this event group on the CPU now.
- */
-static int group_can_go_on(struct perf_event *event,
- struct perf_cpu_context *cpuctx,
- int can_add_hw)
-{
- /*
- * Groups consisting entirely of software events can always go on.
- */
- if (event->group_flags & PERF_GROUP_SOFTWARE)
- return 1;
- /*
- * If an exclusive group is already on, no other hardware
- * events can go on.
- */
- if (cpuctx->exclusive)
- return 0;
- /*
- * If this group is exclusive and there are already
- * events on the CPU, it can't go on.
- */
- if (event->attr.exclusive && cpuctx->active_oncpu)
- return 0;
- /*
- * Otherwise, try to add it if all previous groups were able
- * to go on.
- */
- return can_add_hw;
-}
-
-static void add_event_to_ctx(struct perf_event *event,
- struct perf_event_context *ctx)
-{
- list_add_event(event, ctx);
- perf_group_attach(event);
- event->tstamp_enabled = ctx->time;
- event->tstamp_running = ctx->time;
- event->tstamp_stopped = ctx->time;
-}
-
-/*
- * Cross CPU call to install and enable a performance event
- *
- * Must be called with ctx->mutex held
- */
-static void __perf_install_in_context(void *info)
-{
- struct perf_cpu_context *cpuctx = &__get_cpu_var(perf_cpu_context);
- struct perf_event *event = info;
- struct perf_event_context *ctx = event->ctx;
- struct perf_event *leader = event->group_leader;
- int err;
-
- /*
- * If this is a task context, we need to check whether it is
- * the current task context of this cpu. If not it has been
- * scheduled out before the smp call arrived.
- * Or possibly this is the right context but it isn't
- * on this cpu because it had no events.
- */
- if (ctx->task && cpuctx->task_ctx != ctx) {
- if (cpuctx->task_ctx || ctx->task != current)
- return;
- cpuctx->task_ctx = ctx;
- }
-
- raw_spin_lock(&ctx->lock);
- ctx->is_active = 1;
- update_context_time(ctx);
-
- /*
- * Protect the list operation against NMI by disabling the
- * events on a global level. NOP for non NMI based events.
- */
- perf_disable();
-
- add_event_to_ctx(event, ctx);
-
- if (event->cpu != -1 && event->cpu != smp_processor_id())
- goto unlock;
-
- /*
- * Don't put the event on if it is disabled or if
- * it is in a group and the group isn't on.
- */
- if (event->state != PERF_EVENT_STATE_INACTIVE ||
- (leader != event && leader->state != PERF_EVENT_STATE_ACTIVE))
- goto unlock;
-
- /*
- * An exclusive event can't go on if there are already active
- * hardware events, and no hardware event can go on if there
- * is already an exclusive event on.
- */
- if (!group_can_go_on(event, cpuctx, 1))
- err = -EEXIST;
- else
- err = event_sched_in(event, cpuctx, ctx);
-
- if (err) {
- /*
- * This event couldn't go on. If it is in a group
- * then we have to pull the whole group off.
- * If the event group is pinned then put it in error state.
- */
- if (leader != event)
- group_sched_out(leader, cpuctx, ctx);
- if (leader->attr.pinned) {
- update_group_times(leader);
- leader->state = PERF_EVENT_STATE_ERROR;
- }
- }
-
- if (!err && !ctx->task && cpuctx->max_pertask)
- cpuctx->max_pertask--;
-
- unlock:
- perf_enable();
-
- raw_spin_unlock(&ctx->lock);
-}
-
-/*
- * Attach a performance event to a context
- *
- * First we add the event to the list with the hardware enable bit
- * in event->hw_config cleared.
- *
- * If the event is attached to a task which is on a CPU we use a smp
- * call to enable it in the task context. The task might have been
- * scheduled away, but we check this in the smp call again.
- *
- * Must be called with ctx->mutex held.
- */
-static void
-perf_install_in_context(struct perf_event_context *ctx,
- struct perf_event *event,
- int cpu)
-{
- struct task_struct *task = ctx->task;
-
- if (!task) {
- /*
- * Per cpu events are installed via an smp call and
- * the install is always successful.
- */
- smp_call_function_single(cpu, __perf_install_in_context,
- event, 1);
- return;
- }
-
-retry:
- task_oncpu_function_call(task, __perf_install_in_context,
- event);
-
- raw_spin_lock_irq(&ctx->lock);
- /*
- * we need to retry the smp call.
- */
- if (ctx->is_active && list_empty(&event->group_entry)) {
- raw_spin_unlock_irq(&ctx->lock);
- goto retry;
- }
-
- /*
- * The lock prevents that this context is scheduled in so we
- * can add the event safely, if it the call above did not
- * succeed.
- */
- if (list_empty(&event->group_entry))
- add_event_to_ctx(event, ctx);
- raw_spin_unlock_irq(&ctx->lock);
-}
-
-/*
- * Put a event into inactive state and update time fields.
- * Enabling the leader of a group effectively enables all
- * the group members that aren't explicitly disabled, so we
- * have to update their ->tstamp_enabled also.
- * Note: this works for group members as well as group leaders
- * since the non-leader members' sibling_lists will be empty.
- */
-static void __perf_event_mark_enabled(struct perf_event *event,
- struct perf_event_context *ctx)
-{
- struct perf_event *sub;
-
- event->state = PERF_EVENT_STATE_INACTIVE;
- event->tstamp_enabled = ctx->time - event->total_time_enabled;
- list_for_each_entry(sub, &event->sibling_list, group_entry)
- if (sub->state >= PERF_EVENT_STATE_INACTIVE)
- sub->tstamp_enabled =
- ctx->time - sub->total_time_enabled;
-}
-
-/*
- * Cross CPU call to enable a performance event
- */
-static void __perf_event_enable(void *info)
-{
- struct perf_event *event = info;
- struct perf_cpu_context *cpuctx = &__get_cpu_var(perf_cpu_context);
- struct perf_event_context *ctx = event->ctx;
- struct perf_event *leader = event->group_leader;
- int err;
-
- /*
- * If this is a per-task event, need to check whether this
- * event's task is the current task on this cpu.
- */
- if (ctx->task && cpuctx->task_ctx != ctx) {
- if (cpuctx->task_ctx || ctx->task != current)
- return;
- cpuctx->task_ctx = ctx;
- }
-
- raw_spin_lock(&ctx->lock);
- ctx->is_active = 1;
- update_context_time(ctx);
-
- if (event->state >= PERF_EVENT_STATE_INACTIVE)
- goto unlock;
- __perf_event_mark_enabled(event, ctx);
-
- if (event->cpu != -1 && event->cpu != smp_processor_id())
- goto unlock;
-
- /*
- * If the event is in a group and isn't the group leader,
- * then don't put it on unless the group is on.
- */
- if (leader != event && leader->state != PERF_EVENT_STATE_ACTIVE)
- goto unlock;
-
- if (!group_can_go_on(event, cpuctx, 1)) {
- err = -EEXIST;
- } else {
- perf_disable();
- if (event == leader)
- err = group_sched_in(event, cpuctx, ctx);
- else
- err = event_sched_in(event, cpuctx, ctx);
- perf_enable();
- }
-
- if (err) {
- /*
- * If this event can't go on and it's part of a
- * group, then the whole group has to come off.
- */
- if (leader != event)
- group_sched_out(leader, cpuctx, ctx);
- if (leader->attr.pinned) {
- update_group_times(leader);
- leader->state = PERF_EVENT_STATE_ERROR;
- }
- }
-
- unlock:
- raw_spin_unlock(&ctx->lock);
-}
-
-/*
- * Enable a event.
- *
- * If event->ctx is a cloned context, callers must make sure that
- * every task struct that event->ctx->task could possibly point to
- * remains valid. This condition is satisfied when called through
- * perf_event_for_each_child or perf_event_for_each as described
- * for perf_event_disable.
- */
-void perf_event_enable(struct perf_event *event)
-{
- struct perf_event_context *ctx = event->ctx;
- struct task_struct *task = ctx->task;
-
- if (!task) {
- /*
- * Enable the event on the cpu that it's on
- */
- smp_call_function_single(event->cpu, __perf_event_enable,
- event, 1);
- return;
- }
-
- raw_spin_lock_irq(&ctx->lock);
- if (event->state >= PERF_EVENT_STATE_INACTIVE)
- goto out;
-
- /*
- * If the event is in error state, clear that first.
- * That way, if we see the event in error state below, we
- * know that it has gone back into error state, as distinct
- * from the task having been scheduled away before the
- * cross-call arrived.
- */
- if (event->state == PERF_EVENT_STATE_ERROR)
- event->state = PERF_EVENT_STATE_OFF;
-
- retry:
- raw_spin_unlock_irq(&ctx->lock);
- task_oncpu_function_call(task, __perf_event_enable, event);
-
- raw_spin_lock_irq(&ctx->lock);
-
- /*
- * If the context is active and the event is still off,
- * we need to retry the cross-call.
- */
- if (ctx->is_active && event->state == PERF_EVENT_STATE_OFF)
- goto retry;
-
- /*
- * Since we have the lock this context can't be scheduled
- * in, so we can change the state safely.
- */
- if (event->state == PERF_EVENT_STATE_OFF)
- __perf_event_mark_enabled(event, ctx);
-
- out:
- raw_spin_unlock_irq(&ctx->lock);
-}
-
-static int perf_event_refresh(struct perf_event *event, int refresh)
-{
- /*
- * not supported on inherited events
- */
- if (event->attr.inherit)
- return -EINVAL;
-
- atomic_add(refresh, &event->event_limit);
- perf_event_enable(event);
-
- return 0;
-}
-
-enum event_type_t {
- EVENT_FLEXIBLE = 0x1,
- EVENT_PINNED = 0x2,
- EVENT_ALL = EVENT_FLEXIBLE | EVENT_PINNED,
-};
-
-static void ctx_sched_out(struct perf_event_context *ctx,
- struct perf_cpu_context *cpuctx,
- enum event_type_t event_type)
-{
- struct perf_event *event;
-
- raw_spin_lock(&ctx->lock);
- ctx->is_active = 0;
- if (likely(!ctx->nr_events))
- goto out;
- update_context_time(ctx);
-
- perf_disable();
- if (!ctx->nr_active)
- goto out_enable;
-
- if (event_type & EVENT_PINNED)
- list_for_each_entry(event, &ctx->pinned_groups, group_entry)
- group_sched_out(event, cpuctx, ctx);
-
- if (event_type & EVENT_FLEXIBLE)
- list_for_each_entry(event, &ctx->flexible_groups, group_entry)
- group_sched_out(event, cpuctx, ctx);
-
- out_enable:
- perf_enable();
- out:
- raw_spin_unlock(&ctx->lock);
-}
-
-/*
- * Test whether two contexts are equivalent, i.e. whether they
- * have both been cloned from the same version of the same context
- * and they both have the same number of enabled events.
- * If the number of enabled events is the same, then the set
- * of enabled events should be the same, because these are both
- * inherited contexts, therefore we can't access individual events
- * in them directly with an fd; we can only enable/disable all
- * events via prctl, or enable/disable all events in a family
- * via ioctl, which will have the same effect on both contexts.
- */
-static int context_equiv(struct perf_event_context *ctx1,
- struct perf_event_context *ctx2)
-{
- return ctx1->parent_ctx && ctx1->parent_ctx == ctx2->parent_ctx
- && ctx1->parent_gen == ctx2->parent_gen
- && !ctx1->pin_count && !ctx2->pin_count;
-}
-
-static void __perf_event_sync_stat(struct perf_event *event,
- struct perf_event *next_event)
-{
- u64 value;
-
- if (!event->attr.inherit_stat)
- return;
-
- /*
- * Update the event value, we cannot use perf_event_read()
- * because we're in the middle of a context switch and have IRQs
- * disabled, which upsets smp_call_function_single(), however
- * we know the event must be on the current CPU, therefore we
- * don't need to use it.
- */
- switch (event->state) {
- case PERF_EVENT_STATE_ACTIVE:
- event->pmu->read(event);
- /* fall-through */
-
- case PERF_EVENT_STATE_INACTIVE:
- update_event_times(event);
- break;
-
- default:
- break;
- }
-
- /*
- * In order to keep per-task stats reliable we need to flip the event
- * values when we flip the contexts.
- */
- value = local64_read(&next_event->count);
- value = local64_xchg(&event->count, value);
- local64_set(&next_event->count, value);
-
- swap(event->total_time_enabled, next_event->total_time_enabled);
- swap(event->total_time_running, next_event->total_time_running);
-
- /*
- * Since we swizzled the values, update the user visible data too.
- */
- perf_event_update_userpage(event);
- perf_event_update_userpage(next_event);
-}
-
-#define list_next_entry(pos, member) \
- list_entry(pos->member.next, typeof(*pos), member)
-
-static void perf_event_sync_stat(struct perf_event_context *ctx,
- struct perf_event_context *next_ctx)
-{
- struct perf_event *event, *next_event;
-
- if (!ctx->nr_stat)
- return;
-
- update_context_time(ctx);
-
- event = list_first_entry(&ctx->event_list,
- struct perf_event, event_entry);
-
- next_event = list_first_entry(&next_ctx->event_list,
- struct perf_event, event_entry);
-
- while (&event->event_entry != &ctx->event_list &&
- &next_event->event_entry != &next_ctx->event_list) {
-
- __perf_event_sync_stat(event, next_event);
-
- event = list_next_entry(event, event_entry);
- next_event = list_next_entry(next_event, event_entry);
- }
-}
-
-/*
- * Called from scheduler to remove the events of the current task,
- * with interrupts disabled.
- *
- * We stop each event and update the event value in event->count.
- *
- * This does not protect us against NMI, but disable()
- * sets the disabled bit in the control field of event _before_
- * accessing the event control register. If a NMI hits, then it will
- * not restart the event.
- */
-void perf_event_task_sched_out(struct task_struct *task,
- struct task_struct *next)
-{
- struct perf_cpu_context *cpuctx = &__get_cpu_var(perf_cpu_context);
- struct perf_event_context *ctx = task->perf_event_ctxp;
- struct perf_event_context *next_ctx;
- struct perf_event_context *parent;
- int do_switch = 1;
-
- perf_sw_event(PERF_COUNT_SW_CONTEXT_SWITCHES, 1, 1, NULL, 0);
-
- if (likely(!ctx || !cpuctx->task_ctx))
- return;
-
- rcu_read_lock();
- parent = rcu_dereference(ctx->parent_ctx);
- next_ctx = next->perf_event_ctxp;
- if (parent && next_ctx &&
- rcu_dereference(next_ctx->parent_ctx) == parent) {
- /*
- * Looks like the two contexts are clones, so we might be
- * able to optimize the context switch. We lock both
- * contexts and check that they are clones under the
- * lock (including re-checking that neither has been
- * uncloned in the meantime). It doesn't matter which
- * order we take the locks because no other cpu could
- * be trying to lock both of these tasks.
- */
- raw_spin_lock(&ctx->lock);
- raw_spin_lock_nested(&next_ctx->lock, SINGLE_DEPTH_NESTING);
- if (context_equiv(ctx, next_ctx)) {
- /*
- * XXX do we need a memory barrier of sorts
- * wrt to rcu_dereference() of perf_event_ctxp
- */
- task->perf_event_ctxp = next_ctx;
- next->perf_event_ctxp = ctx;
- ctx->task = next;
- next_ctx->task = task;
- do_switch = 0;
-
- perf_event_sync_stat(ctx, next_ctx);
- }
- raw_spin_unlock(&next_ctx->lock);
- raw_spin_unlock(&ctx->lock);
- }
- rcu_read_unlock();
-
- if (do_switch) {
- ctx_sched_out(ctx, cpuctx, EVENT_ALL);
- cpuctx->task_ctx = NULL;
- }
-}
-
-static void task_ctx_sched_out(struct perf_event_context *ctx,
- enum event_type_t event_type)
-{
- struct perf_cpu_context *cpuctx = &__get_cpu_var(perf_cpu_context);
-
- if (!cpuctx->task_ctx)
- return;
-
- if (WARN_ON_ONCE(ctx != cpuctx->task_ctx))
- return;
-
- ctx_sched_out(ctx, cpuctx, event_type);
- cpuctx->task_ctx = NULL;
-}
-
-/*
- * Called with IRQs disabled
- */
-static void __perf_event_task_sched_out(struct perf_event_context *ctx)
-{
- task_ctx_sched_out(ctx, EVENT_ALL);
-}
-
-/*
- * Called with IRQs disabled
- */
-static void cpu_ctx_sched_out(struct perf_cpu_context *cpuctx,
- enum event_type_t event_type)
-{
- ctx_sched_out(&cpuctx->ctx, cpuctx, event_type);
-}
-
-static void
-ctx_pinned_sched_in(struct perf_event_context *ctx,
- struct perf_cpu_context *cpuctx)
-{
- struct perf_event *event;
-
- list_for_each_entry(event, &ctx->pinned_groups, group_entry) {
- if (event->state <= PERF_EVENT_STATE_OFF)
- continue;
- if (event->cpu != -1 && event->cpu != smp_processor_id())
- continue;
-
- if (group_can_go_on(event, cpuctx, 1))
- group_sched_in(event, cpuctx, ctx);
-
- /*
- * If this pinned group hasn't been scheduled,
- * put it in error state.
- */
- if (event->state == PERF_EVENT_STATE_INACTIVE) {
- update_group_times(event);
- event->state = PERF_EVENT_STATE_ERROR;
- }
- }
-}
-
-static void
-ctx_flexible_sched_in(struct perf_event_context *ctx,
- struct perf_cpu_context *cpuctx)
-{
- struct perf_event *event;
- int can_add_hw = 1;
-
- list_for_each_entry(event, &ctx->flexible_groups, group_entry) {
- /* Ignore events in OFF or ERROR state */
- if (event->state <= PERF_EVENT_STATE_OFF)
- continue;
- /*
- * Listen to the 'cpu' scheduling filter constraint
- * of events:
- */
- if (event->cpu != -1 && event->cpu != smp_processor_id())
- continue;
-
- if (group_can_go_on(event, cpuctx, can_add_hw))
- if (group_sched_in(event, cpuctx, ctx))
- can_add_hw = 0;
- }
-}
-
-static void
-ctx_sched_in(struct perf_event_context *ctx,
- struct perf_cpu_context *cpuctx,
- enum event_type_t event_type)
-{
- raw_spin_lock(&ctx->lock);
- ctx->is_active = 1;
- if (likely(!ctx->nr_events))
- goto out;
-
- ctx->timestamp = perf_clock();
-
- perf_disable();
-
- /*
- * First go through the list and put on any pinned groups
- * in order to give them the best chance of going on.
- */
- if (event_type & EVENT_PINNED)
- ctx_pinned_sched_in(ctx, cpuctx);
-
- /* Then walk through the lower prio flexible groups */
- if (event_type & EVENT_FLEXIBLE)
- ctx_flexible_sched_in(ctx, cpuctx);
-
- perf_enable();
- out:
- raw_spin_unlock(&ctx->lock);
-}
-
-static void cpu_ctx_sched_in(struct perf_cpu_context *cpuctx,
- enum event_type_t event_type)
-{
- struct perf_event_context *ctx = &cpuctx->ctx;
-
- ctx_sched_in(ctx, cpuctx, event_type);
-}
-
-static void task_ctx_sched_in(struct task_struct *task,
- enum event_type_t event_type)
-{
- struct perf_cpu_context *cpuctx = &__get_cpu_var(perf_cpu_context);
- struct perf_event_context *ctx = task->perf_event_ctxp;
-
- if (likely(!ctx))
- return;
- if (cpuctx->task_ctx == ctx)
- return;
- ctx_sched_in(ctx, cpuctx, event_type);
- cpuctx->task_ctx = ctx;
-}
-/*
- * Called from scheduler to add the events of the current task
- * with interrupts disabled.
- *
- * We restore the event value and then enable it.
- *
- * This does not protect us against NMI, but enable()
- * sets the enabled bit in the control field of event _before_
- * accessing the event control register. If a NMI hits, then it will
- * keep the event running.
- */
-void perf_event_task_sched_in(struct task_struct *task)
-{
- struct perf_cpu_context *cpuctx = &__get_cpu_var(perf_cpu_context);
- struct perf_event_context *ctx = task->perf_event_ctxp;
-
- if (likely(!ctx))
- return;
-
- if (cpuctx->task_ctx == ctx)
- return;
-
- perf_disable();
-
- /*
- * We want to keep the following priority order:
- * cpu pinned (that don't need to move), task pinned,
- * cpu flexible, task flexible.
- */
- cpu_ctx_sched_out(cpuctx, EVENT_FLEXIBLE);
-
- ctx_sched_in(ctx, cpuctx, EVENT_PINNED);
- cpu_ctx_sched_in(cpuctx, EVENT_FLEXIBLE);
- ctx_sched_in(ctx, cpuctx, EVENT_FLEXIBLE);
-
- cpuctx->task_ctx = ctx;
-
- perf_enable();
-}
-
-#define MAX_INTERRUPTS (~0ULL)
-
-static void perf_log_throttle(struct perf_event *event, int enable);
-
-static u64 perf_calculate_period(struct perf_event *event, u64 nsec, u64 count)
-{
- u64 frequency = event->attr.sample_freq;
- u64 sec = NSEC_PER_SEC;
- u64 divisor, dividend;
-
- int count_fls, nsec_fls, frequency_fls, sec_fls;
-
- count_fls = fls64(count);
- nsec_fls = fls64(nsec);
- frequency_fls = fls64(frequency);
- sec_fls = 30;
-
- /*
- * We got @count in @nsec, with a target of sample_freq HZ
- * the target period becomes:
- *
- * @count * 10^9
- * period = -------------------
- * @nsec * sample_freq
- *
- */
-
- /*
- * Reduce accuracy by one bit such that @a and @b converge
- * to a similar magnitude.
- */
-#define REDUCE_FLS(a, b) \
-do { \
- if (a##_fls > b##_fls) { \
- a >>= 1; \
- a##_fls--; \
- } else { \
- b >>= 1; \
- b##_fls--; \
- } \
-} while (0)
-
- /*
- * Reduce accuracy until either term fits in a u64, then proceed with
- * the other, so that finally we can do a u64/u64 division.
- */
- while (count_fls + sec_fls > 64 && nsec_fls + frequency_fls > 64) {
- REDUCE_FLS(nsec, frequency);
- REDUCE_FLS(sec, count);
- }
-
- if (count_fls + sec_fls > 64) {
- divisor = nsec * frequency;
-
- while (count_fls + sec_fls > 64) {
- REDUCE_FLS(count, sec);
- divisor >>= 1;
- }
-
- dividend = count * sec;
- } else {
- dividend = count * sec;
-
- while (nsec_fls + frequency_fls > 64) {
- REDUCE_FLS(nsec, frequency);
- dividend >>= 1;
- }
-
- divisor = nsec * frequency;
- }
-
- if (!divisor)
- return dividend;
-
- return div64_u64(dividend, divisor);
-}
-
-static void perf_event_stop(struct perf_event *event)
-{
- if (!event->pmu->stop)
- return event->pmu->disable(event);
-
- return event->pmu->stop(event);
-}
-
-static int perf_event_start(struct perf_event *event)
-{
- if (!event->pmu->start)
- return event->pmu->enable(event);
-
- return event->pmu->start(event);
-}
-
-static void perf_adjust_period(struct perf_event *event, u64 nsec, u64 count)
-{
- struct hw_perf_event *hwc = &event->hw;
- s64 period, sample_period;
- s64 delta;
-
- period = perf_calculate_period(event, nsec, count);
-
- delta = (s64)(period - hwc->sample_period);
- delta = (delta + 7) / 8; /* low pass filter */
-
- sample_period = hwc->sample_period + delta;
-
- if (!sample_period)
- sample_period = 1;
-
- hwc->sample_period = sample_period;
-
- if (local64_read(&hwc->period_left) > 8*sample_period) {
- perf_disable();
- perf_event_stop(event);
- local64_set(&hwc->period_left, 0);
- perf_event_start(event);
- perf_enable();
- }
-}
-
-static void perf_ctx_adjust_freq(struct perf_event_context *ctx)
-{
- struct perf_event *event;
- struct hw_perf_event *hwc;
- u64 interrupts, now;
- s64 delta;
-
- raw_spin_lock(&ctx->lock);
- list_for_each_entry_rcu(event, &ctx->event_list, event_entry) {
- if (event->state != PERF_EVENT_STATE_ACTIVE)
- continue;
-
- if (event->cpu != -1 && event->cpu != smp_processor_id())
- continue;
-
- hwc = &event->hw;
-
- interrupts = hwc->interrupts;
- hwc->interrupts = 0;
-
- /*
- * unthrottle events on the tick
- */
- if (interrupts == MAX_INTERRUPTS) {
- perf_log_throttle(event, 1);
- perf_disable();
- event->pmu->unthrottle(event);
- perf_enable();
- }
-
- if (!event->attr.freq || !event->attr.sample_freq)
- continue;
-
- perf_disable();
- event->pmu->read(event);
- now = local64_read(&event->count);
- delta = now - hwc->freq_count_stamp;
- hwc->freq_count_stamp = now;
-
- if (delta > 0)
- perf_adjust_period(event, TICK_NSEC, delta);
- perf_enable();
- }
- raw_spin_unlock(&ctx->lock);
-}
-
-/*
- * Round-robin a context's events:
- */
-static void rotate_ctx(struct perf_event_context *ctx)
-{
- raw_spin_lock(&ctx->lock);
-
- /* Rotate the first entry last of non-pinned groups */
- list_rotate_left(&ctx->flexible_groups);
-
- raw_spin_unlock(&ctx->lock);
-}
-
-void perf_event_task_tick(struct task_struct *curr)
-{
- struct perf_cpu_context *cpuctx;
- struct perf_event_context *ctx;
- int rotate = 0;
-
- if (!atomic_read(&nr_events))
- return;
-
- cpuctx = &__get_cpu_var(perf_cpu_context);
- if (cpuctx->ctx.nr_events &&
- cpuctx->ctx.nr_events != cpuctx->ctx.nr_active)
- rotate = 1;
-
- ctx = curr->perf_event_ctxp;
- if (ctx && ctx->nr_events && ctx->nr_events != ctx->nr_active)
- rotate = 1;
-
- perf_ctx_adjust_freq(&cpuctx->ctx);
- if (ctx)
- perf_ctx_adjust_freq(ctx);
-
- if (!rotate)
- return;
-
- perf_disable();
- cpu_ctx_sched_out(cpuctx, EVENT_FLEXIBLE);
- if (ctx)
- task_ctx_sched_out(ctx, EVENT_FLEXIBLE);
-
- rotate_ctx(&cpuctx->ctx);
- if (ctx)
- rotate_ctx(ctx);
-
- cpu_ctx_sched_in(cpuctx, EVENT_FLEXIBLE);
- if (ctx)
- task_ctx_sched_in(curr, EVENT_FLEXIBLE);
- perf_enable();
-}
-
-static int event_enable_on_exec(struct perf_event *event,
- struct perf_event_context *ctx)
-{
- if (!event->attr.enable_on_exec)
- return 0;
-
- event->attr.enable_on_exec = 0;
- if (event->state >= PERF_EVENT_STATE_INACTIVE)
- return 0;
-
- __perf_event_mark_enabled(event, ctx);
-
- return 1;
-}
-
-/*
- * Enable all of a task's events that have been marked enable-on-exec.
- * This expects task == current.
- */
-static void perf_event_enable_on_exec(struct task_struct *task)
-{
- struct perf_event_context *ctx;
- struct perf_event *event;
- unsigned long flags;
- int enabled = 0;
- int ret;
-
- local_irq_save(flags);
- ctx = task->perf_event_ctxp;
- if (!ctx || !ctx->nr_events)
- goto out;
-
- __perf_event_task_sched_out(ctx);
-
- raw_spin_lock(&ctx->lock);
-
- list_for_each_entry(event, &ctx->pinned_groups, group_entry) {
- ret = event_enable_on_exec(event, ctx);
- if (ret)
- enabled = 1;
- }
-
- list_for_each_entry(event, &ctx->flexible_groups, group_entry) {
- ret = event_enable_on_exec(event, ctx);
- if (ret)
- enabled = 1;
- }
-
- /*
- * Unclone this context if we enabled any event.
- */
- if (enabled)
- unclone_ctx(ctx);
-
- raw_spin_unlock(&ctx->lock);
-
- perf_event_task_sched_in(task);
- out:
- local_irq_restore(flags);
-}
-
-/*
- * Cross CPU call to read the hardware event
- */
-static void __perf_event_read(void *info)
-{
- struct perf_cpu_context *cpuctx = &__get_cpu_var(perf_cpu_context);
- struct perf_event *event = info;
- struct perf_event_context *ctx = event->ctx;
-
- /*
- * If this is a task context, we need to check whether it is
- * the current task context of this cpu. If not it has been
- * scheduled out before the smp call arrived. In that case
- * event->count would have been updated to a recent sample
- * when the event was scheduled out.
- */
- if (ctx->task && cpuctx->task_ctx != ctx)
- return;
-
- raw_spin_lock(&ctx->lock);
- update_context_time(ctx);
- update_event_times(event);
- raw_spin_unlock(&ctx->lock);
-
- event->pmu->read(event);
-}
-
-static inline u64 perf_event_count(struct perf_event *event)
-{
- return local64_read(&event->count) + atomic64_read(&event->child_count);
-}
-
-static u64 perf_event_read(struct perf_event *event)
-{
- /*
- * If event is enabled and currently active on a CPU, update the
- * value in the event structure:
- */
- if (event->state == PERF_EVENT_STATE_ACTIVE) {
- smp_call_function_single(event->oncpu,
- __perf_event_read, event, 1);
- } else if (event->state == PERF_EVENT_STATE_INACTIVE) {
- struct perf_event_context *ctx = event->ctx;
- unsigned long flags;
-
- raw_spin_lock_irqsave(&ctx->lock, flags);
- update_context_time(ctx);
- update_event_times(event);
- raw_spin_unlock_irqrestore(&ctx->lock, flags);
- }
-
- return perf_event_count(event);
-}
-
-/*
- * Initialize the perf_event context in a task_struct:
- */
-static void
-__perf_event_init_context(struct perf_event_context *ctx,
- struct task_struct *task)
-{
- raw_spin_lock_init(&ctx->lock);
- mutex_init(&ctx->mutex);
- INIT_LIST_HEAD(&ctx->pinned_groups);
- INIT_LIST_HEAD(&ctx->flexible_groups);
- INIT_LIST_HEAD(&ctx->event_list);
- atomic_set(&ctx->refcount, 1);
- ctx->task = task;
-}
-
-static struct perf_event_context *find_get_context(pid_t pid, int cpu)
-{
- struct perf_event_context *ctx;
- struct perf_cpu_context *cpuctx;
- struct task_struct *task;
- unsigned long flags;
- int err;
-
- if (pid == -1 && cpu != -1) {
- /* Must be root to operate on a CPU event: */
- if (perf_paranoid_cpu() && !capable(CAP_SYS_ADMIN))
- return ERR_PTR(-EACCES);
-
- if (cpu < 0 || cpu >= nr_cpumask_bits)
- return ERR_PTR(-EINVAL);
-
- /*
- * We could be clever and allow to attach a event to an
- * offline CPU and activate it when the CPU comes up, but
- * that's for later.
- */
- if (!cpu_online(cpu))
- return ERR_PTR(-ENODEV);
-
- cpuctx = &per_cpu(perf_cpu_context, cpu);
- ctx = &cpuctx->ctx;
- get_ctx(ctx);
-
- return ctx;
- }
-
- rcu_read_lock();
- if (!pid)
- task = current;
- else
- task = find_task_by_vpid(pid);
- if (task)
- get_task_struct(task);
- rcu_read_unlock();
-
- if (!task)
- return ERR_PTR(-ESRCH);
-
- /*
- * Can't attach events to a dying task.
- */
- err = -ESRCH;
- if (task->flags & PF_EXITING)
- goto errout;
-
- /* Reuse ptrace permission checks for now. */
- err = -EACCES;
- if (!ptrace_may_access(task, PTRACE_MODE_READ))
- goto errout;
-
- retry:
- ctx = perf_lock_task_context(task, &flags);
- if (ctx) {
- unclone_ctx(ctx);
- raw_spin_unlock_irqrestore(&ctx->lock, flags);
- }
-
- if (!ctx) {
- ctx = kzalloc(sizeof(struct perf_event_context), GFP_KERNEL);
- err = -ENOMEM;
- if (!ctx)
- goto errout;
- __perf_event_init_context(ctx, task);
- get_ctx(ctx);
- if (cmpxchg(&task->perf_event_ctxp, NULL, ctx)) {
- /*
- * We raced with some other task; use
- * the context they set.
- */
- kfree(ctx);
- goto retry;
- }
- get_task_struct(task);
- }
-
- put_task_struct(task);
- return ctx;
-
- errout:
- put_task_struct(task);
- return ERR_PTR(err);
-}
-
-static void perf_event_free_filter(struct perf_event *event);
-
-static void free_event_rcu(struct rcu_head *head)
-{
- struct perf_event *event;
-
- event = container_of(head, struct perf_event, rcu_head);
- if (event->ns)
- put_pid_ns(event->ns);
- perf_event_free_filter(event);
- kfree(event);
-}
-
-static void perf_pending_sync(struct perf_event *event);
-static void perf_buffer_put(struct perf_buffer *buffer);
-
-static void free_event(struct perf_event *event)
-{
- perf_pending_sync(event);
-
- if (!event->parent) {
- atomic_dec(&nr_events);
- if (event->attr.mmap || event->attr.mmap_data)
- atomic_dec(&nr_mmap_events);
- if (event->attr.comm)
- atomic_dec(&nr_comm_events);
- if (event->attr.task)
- atomic_dec(&nr_task_events);
- }
-
- if (event->buffer) {
- perf_buffer_put(event->buffer);
- event->buffer = NULL;
- }
-
- if (event->destroy)
- event->destroy(event);
-
- put_ctx(event->ctx);
- call_rcu(&event->rcu_head, free_event_rcu);
-}
-
-int perf_event_release_kernel(struct perf_event *event)
-{
- struct perf_event_context *ctx = event->ctx;
-
- /*
- * Remove from the PMU, can't get re-enabled since we got
- * here because the last ref went.
- */
- perf_event_disable(event);
-
- WARN_ON_ONCE(ctx->parent_ctx);
- /*
- * There are two ways this annotation is useful:
- *
- * 1) there is a lock recursion from perf_event_exit_task
- * see the comment there.
- *
- * 2) there is a lock-inversion with mmap_sem through
- * perf_event_read_group(), which takes faults while
- * holding ctx->mutex, however this is called after
- * the last filedesc died, so there is no possibility
- * to trigger the AB-BA case.
- */
- mutex_lock_nested(&ctx->mutex, SINGLE_DEPTH_NESTING);
- raw_spin_lock_irq(&ctx->lock);
- perf_group_detach(event);
- list_del_event(event, ctx);
- raw_spin_unlock_irq(&ctx->lock);
- mutex_unlock(&ctx->mutex);
-
- mutex_lock(&event->owner->perf_event_mutex);
- list_del_init(&event->owner_entry);
- mutex_unlock(&event->owner->perf_event_mutex);
- put_task_struct(event->owner);
-
- free_event(event);
-
- return 0;
-}
-EXPORT_SYMBOL_GPL(perf_event_release_kernel);
-
-/*
- * Called when the last reference to the file is gone.
- */
-static int perf_release(struct inode *inode, struct file *file)
-{
- struct perf_event *event = file->private_data;
-
- file->private_data = NULL;
-
- return perf_event_release_kernel(event);
-}
-
-static int perf_event_read_size(struct perf_event *event)
-{
- int entry = sizeof(u64); /* value */
- int size = 0;
- int nr = 1;
-
- if (event->attr.read_format & PERF_FORMAT_TOTAL_TIME_ENABLED)
- size += sizeof(u64);
-
- if (event->attr.read_format & PERF_FORMAT_TOTAL_TIME_RUNNING)
- size += sizeof(u64);
-
- if (event->attr.read_format & PERF_FORMAT_ID)
- entry += sizeof(u64);
-
- if (event->attr.read_format & PERF_FORMAT_GROUP) {
- nr += event->group_leader->nr_siblings;
- size += sizeof(u64);
- }
-
- size += entry * nr;
-
- return size;
-}
-
-u64 perf_event_read_value(struct perf_event *event, u64 *enabled, u64 *running)
-{
- struct perf_event *child;
- u64 total = 0;
-
- *enabled = 0;
- *running = 0;
-
- mutex_lock(&event->child_mutex);
- total += perf_event_read(event);
- *enabled += event->total_time_enabled +
- atomic64_read(&event->child_total_time_enabled);
- *running += event->total_time_running +
- atomic64_read(&event->child_total_time_running);
-
- list_for_each_entry(child, &event->child_list, child_list) {
- total += perf_event_read(child);
- *enabled += child->total_time_enabled;
- *running += child->total_time_running;
- }
- mutex_unlock(&event->child_mutex);
-
- return total;
-}
-EXPORT_SYMBOL_GPL(perf_event_read_value);
-
-static int perf_event_read_group(struct perf_event *event,
- u64 read_format, char __user *buf)
-{
- struct perf_event *leader = event->group_leader, *sub;
- int n = 0, size = 0, ret = -EFAULT;
- struct perf_event_context *ctx = leader->ctx;
- u64 values[5];
- u64 count, enabled, running;
-
- mutex_lock(&ctx->mutex);
- count = perf_event_read_value(leader, &enabled, &running);
-
- values[n++] = 1 + leader->nr_siblings;
- if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED)
- values[n++] = enabled;
- if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING)
- values[n++] = running;
- values[n++] = count;
- if (read_format & PERF_FORMAT_ID)
- values[n++] = primary_event_id(leader);
-
- size = n * sizeof(u64);
-
- if (copy_to_user(buf, values, size))
- goto unlock;
-
- ret = size;
-
- list_for_each_entry(sub, &leader->sibling_list, group_entry) {
- n = 0;
-
- values[n++] = perf_event_read_value(sub, &enabled, &running);
- if (read_format & PERF_FORMAT_ID)
- values[n++] = primary_event_id(sub);
-
- size = n * sizeof(u64);
-
- if (copy_to_user(buf + ret, values, size)) {
- ret = -EFAULT;
- goto unlock;
- }
-
- ret += size;
- }
-unlock:
- mutex_unlock(&ctx->mutex);
-
- return ret;
-}
-
-static int perf_event_read_one(struct perf_event *event,
- u64 read_format, char __user *buf)
-{
- u64 enabled, running;
- u64 values[4];
- int n = 0;
-
- values[n++] = perf_event_read_value(event, &enabled, &running);
- if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED)
- values[n++] = enabled;
- if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING)
- values[n++] = running;
- if (read_format & PERF_FORMAT_ID)
- values[n++] = primary_event_id(event);
-
- if (copy_to_user(buf, values, n * sizeof(u64)))
- return -EFAULT;
-
- return n * sizeof(u64);
-}
-
-/*
- * Read the performance event - simple non blocking version for now
- */
-static ssize_t
-perf_read_hw(struct perf_event *event, char __user *buf, size_t count)
-{
- u64 read_format = event->attr.read_format;
- int ret;
-
- /*
- * Return end-of-file for a read on a event that is in
- * error state (i.e. because it was pinned but it couldn't be
- * scheduled on to the CPU at some point).
- */
- if (event->state == PERF_EVENT_STATE_ERROR)
- return 0;
-
- if (count < perf_event_read_size(event))
- return -ENOSPC;
-
- WARN_ON_ONCE(event->ctx->parent_ctx);
- if (read_format & PERF_FORMAT_GROUP)
- ret = perf_event_read_group(event, read_format, buf);
- else
- ret = perf_event_read_one(event, read_format, buf);
-
- return ret;
-}
-
-static ssize_t
-perf_read(struct file *file, char __user *buf, size_t count, loff_t *ppos)
-{
- struct perf_event *event = file->private_data;
-
- return perf_read_hw(event, buf, count);
-}
-
-static unsigned int perf_poll(struct file *file, poll_table *wait)
-{
- struct perf_event *event = file->private_data;
- struct perf_buffer *buffer;
- unsigned int events = POLL_HUP;
-
- rcu_read_lock();
- buffer = rcu_dereference(event->buffer);
- if (buffer)
- events = atomic_xchg(&buffer->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);
- local64_set(&event->count, 0);
- perf_event_update_userpage(event);
-}
-
-/*
- * Holding the top-level event's child_mutex means that any
- * descendant process that has inherited this event will block
- * in sync_child_event if it goes to exit, thus satisfying the
- * task existence requirements of perf_event_enable/disable.
- */
-static void perf_event_for_each_child(struct perf_event *event,
- void (*func)(struct perf_event *))
-{
- struct perf_event *child;
-
- WARN_ON_ONCE(event->ctx->parent_ctx);
- mutex_lock(&event->child_mutex);
- func(event);
- list_for_each_entry(child, &event->child_list, child_list)
- func(child);
- mutex_unlock(&event->child_mutex);
-}
-
-static void perf_event_for_each(struct perf_event *event,
- void (*func)(struct perf_event *))
-{
- struct perf_event_context *ctx = event->ctx;
- struct perf_event *sibling;
-
- WARN_ON_ONCE(ctx->parent_ctx);
- mutex_lock(&ctx->mutex);
- event = event->group_leader;
-
- perf_event_for_each_child(event, func);
- 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;
- int ret = 0;
- u64 value;
-
- if (!event->attr.sample_period)
- return -EINVAL;
-
- if (copy_from_user(&value, arg, sizeof(value)))
- return -EFAULT;
-
- if (!value)
- return -EINVAL;
-
- raw_spin_lock_irq(&ctx->lock);
- if (event->attr.freq) {
- if (value > sysctl_perf_event_sample_rate) {
- ret = -EINVAL;
- goto unlock;
- }
-
- event->attr.sample_freq = value;
- } else {
- event->attr.sample_period = value;
- event->hw.sample_period = value;
- }
-unlock:
- raw_spin_unlock_irq(&ctx->lock);
-
- return ret;
-}
-
-static const struct file_operations perf_fops;
-
-static struct perf_event *perf_fget_light(int fd, int *fput_needed)
-{
- struct file *file;
-
- file = fget_light(fd, fput_needed);
- if (!file)
- return ERR_PTR(-EBADF);
-
- if (file->f_op != &perf_fops) {
- fput_light(file, *fput_needed);
- *fput_needed = 0;
- return ERR_PTR(-EBADF);
- }
-
- return file->private_data;
-}
-
-static int perf_event_set_output(struct perf_event *event,
- struct perf_event *output_event);
-static int perf_event_set_filter(struct perf_event *event, void __user *arg);
-
-static long perf_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
-{
- struct perf_event *event = file->private_data;
- void (*func)(struct perf_event *);
- u32 flags = arg;
-
- switch (cmd) {
- case PERF_EVENT_IOC_ENABLE:
- func = perf_event_enable;
- break;
- case PERF_EVENT_IOC_DISABLE:
- func = perf_event_disable;
- break;
- case PERF_EVENT_IOC_RESET:
- func = perf_event_reset;
- break;
-
- case PERF_EVENT_IOC_REFRESH:
- return perf_event_refresh(event, arg);
-
- case PERF_EVENT_IOC_PERIOD:
- return perf_event_period(event, (u64 __user *)arg);
-
- case PERF_EVENT_IOC_SET_OUTPUT:
- {
- struct perf_event *output_event = NULL;
- int fput_needed = 0;
- int ret;
-
- if (arg != -1) {
- output_event = perf_fget_light(arg, &fput_needed);
- if (IS_ERR(output_event))
- return PTR_ERR(output_event);
- }
-
- ret = perf_event_set_output(event, output_event);
- if (output_event)
- fput_light(output_event->filp, fput_needed);
-
- return ret;
- }
-
- case PERF_EVENT_IOC_SET_FILTER:
- return perf_event_set_filter(event, (void __user *)arg);
-
- default:
- return -ENOTTY;
- }
-
- if (flags & PERF_IOC_FLAG_GROUP)
- perf_event_for_each(event, func);
- else
- perf_event_for_each_child(event, func);
-
- return 0;
-}
-
-int perf_event_task_enable(void)
-{
- struct perf_event *event;
-
- mutex_lock(&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_buffer *buffer;
-
- rcu_read_lock();
- buffer = rcu_dereference(event->buffer);
- if (!buffer)
- goto unlock;
-
- userpg = buffer->user_page;
-
- /*
- * Disable preemption so as to not let the corresponding user-space
- * spin too long if we get preempted.
- */
- preempt_disable();
- ++userpg->lock;
- barrier();
- userpg->index = perf_event_index(event);
- userpg->offset = perf_event_count(event);
- if (event->state == PERF_EVENT_STATE_ACTIVE)
- userpg->offset -= local64_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 unsigned long perf_data_size(struct perf_buffer *buffer);
-
-static void
-perf_buffer_init(struct perf_buffer *buffer, long watermark, int flags)
-{
- long max_size = perf_data_size(buffer);
-
- if (watermark)
- buffer->watermark = min(max_size, watermark);
-
- if (!buffer->watermark)
- buffer->watermark = max_size / 2;
-
- if (flags & PERF_BUFFER_WRITABLE)
- buffer->writable = 1;
-
- atomic_set(&buffer->refcount, 1);
-}
-
-#ifndef CONFIG_PERF_USE_VMALLOC
-
-/*
- * Back perf_mmap() with regular GFP_KERNEL-0 pages.
- */
-
-static struct page *
-perf_mmap_to_page(struct perf_buffer *buffer, unsigned long pgoff)
-{
- if (pgoff > buffer->nr_pages)
- return NULL;
-
- if (pgoff == 0)
- return virt_to_page(buffer->user_page);
-
- return virt_to_page(buffer->data_pages[pgoff - 1]);
-}
-
-static void *perf_mmap_alloc_page(int cpu)
-{
- struct page *page;
- int node;
-
- node = (cpu == -1) ? cpu : cpu_to_node(cpu);
- page = alloc_pages_node(node, GFP_KERNEL | __GFP_ZERO, 0);
- if (!page)
- return NULL;
-
- return page_address(page);
-}
-
-static struct perf_buffer *
-perf_buffer_alloc(int nr_pages, long watermark, int cpu, int flags)
-{
- struct perf_buffer *buffer;
- unsigned long size;
- int i;
-
- size = sizeof(struct perf_buffer);
- size += nr_pages * sizeof(void *);
-
- buffer = kzalloc(size, GFP_KERNEL);
- if (!buffer)
- goto fail;
-
- buffer->user_page = perf_mmap_alloc_page(cpu);
- if (!buffer->user_page)
- goto fail_user_page;
-
- for (i = 0; i < nr_pages; i++) {
- buffer->data_pages[i] = perf_mmap_alloc_page(cpu);
- if (!buffer->data_pages[i])
- goto fail_data_pages;
- }
-
- buffer->nr_pages = nr_pages;
-
- perf_buffer_init(buffer, watermark, flags);
-
- return buffer;
-
-fail_data_pages:
- for (i--; i >= 0; i--)
- free_page((unsigned long)buffer->data_pages[i]);
-
- free_page((unsigned long)buffer->user_page);
-
-fail_user_page:
- kfree(buffer);
-
-fail:
- return NULL;
-}
-
-static void perf_mmap_free_page(unsigned long addr)
-{
- struct page *page = virt_to_page((void *)addr);
-
- page->mapping = NULL;
- __free_page(page);
-}
-
-static void perf_buffer_free(struct perf_buffer *buffer)
-{
- int i;
-
- perf_mmap_free_page((unsigned long)buffer->user_page);
- for (i = 0; i < buffer->nr_pages; i++)
- perf_mmap_free_page((unsigned long)buffer->data_pages[i]);
- kfree(buffer);
-}
-
-static inline int page_order(struct perf_buffer *buffer)
-{
- return 0;
-}
-
-#else
-
-/*
- * Back perf_mmap() with vmalloc memory.
- *
- * Required for architectures that have d-cache aliasing issues.
- */
-
-static inline int page_order(struct perf_buffer *buffer)
-{
- return buffer->page_order;
-}
-
-static struct page *
-perf_mmap_to_page(struct perf_buffer *buffer, unsigned long pgoff)
-{
- if (pgoff > (1UL << page_order(buffer)))
- return NULL;
-
- return vmalloc_to_page((void *)buffer->user_page + pgoff * PAGE_SIZE);
-}
-
-static void perf_mmap_unmark_page(void *addr)
-{
- struct page *page = vmalloc_to_page(addr);
-
- page->mapping = NULL;
-}
-
-static void perf_buffer_free_work(struct work_struct *work)
-{
- struct perf_buffer *buffer;
- void *base;
- int i, nr;
-
- buffer = container_of(work, struct perf_buffer, work);
- nr = 1 << page_order(buffer);
-
- base = buffer->user_page;
- for (i = 0; i < nr + 1; i++)
- perf_mmap_unmark_page(base + (i * PAGE_SIZE));
-
- vfree(base);
- kfree(buffer);
-}
-
-static void perf_buffer_free(struct perf_buffer *buffer)
-{
- schedule_work(&buffer->work);
-}
-
-static struct perf_buffer *
-perf_buffer_alloc(int nr_pages, long watermark, int cpu, int flags)
-{
- struct perf_buffer *buffer;
- unsigned long size;
- void *all_buf;
-
- size = sizeof(struct perf_buffer);
- size += sizeof(void *);
-
- buffer = kzalloc(size, GFP_KERNEL);
- if (!buffer)
- goto fail;
-
- INIT_WORK(&buffer->work, perf_buffer_free_work);
-
- all_buf = vmalloc_user((nr_pages + 1) * PAGE_SIZE);
- if (!all_buf)
- goto fail_all_buf;
-
- buffer->user_page = all_buf;
- buffer->data_pages[0] = all_buf + PAGE_SIZE;
- buffer->page_order = ilog2(nr_pages);
- buffer->nr_pages = 1;
-
- perf_buffer_init(buffer, watermark, flags);
-
- return buffer;
-
-fail_all_buf:
- kfree(buffer);
-
-fail:
- return NULL;
-}
-
-#endif
-
-static unsigned long perf_data_size(struct perf_buffer *buffer)
-{
- return buffer->nr_pages << (PAGE_SHIFT + page_order(buffer));
-}
-
-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_buffer *buffer;
- int ret = VM_FAULT_SIGBUS;
-
- if (vmf->flags & FAULT_FLAG_MKWRITE) {
- if (vmf->pgoff == 0)
- ret = 0;
- return ret;
- }
-
- rcu_read_lock();
- buffer = rcu_dereference(event->buffer);
- if (!buffer)
- goto unlock;
-
- if (vmf->pgoff && (vmf->flags & FAULT_FLAG_WRITE))
- goto unlock;
-
- vmf->page = perf_mmap_to_page(buffer, vmf->pgoff);
- if (!vmf->page)
- goto unlock;
-
- get_page(vmf->page);
- vmf->page->mapping = vma->vm_file->f_mapping;
- vmf->page->index = vmf->pgoff;
-
- ret = 0;
-unlock:
- rcu_read_unlock();
-
- return ret;
-}
-
-static void perf_buffer_free_rcu(struct rcu_head *rcu_head)
-{
- struct perf_buffer *buffer;
-
- buffer = container_of(rcu_head, struct perf_buffer, rcu_head);
- perf_buffer_free(buffer);
-}
-
-static struct perf_buffer *perf_buffer_get(struct perf_event *event)
-{
- struct perf_buffer *buffer;
-
- rcu_read_lock();
- buffer = rcu_dereference(event->buffer);
- if (buffer) {
- if (!atomic_inc_not_zero(&buffer->refcount))
- buffer = NULL;
- }
- rcu_read_unlock();
-
- return buffer;
-}
-
-static void perf_buffer_put(struct perf_buffer *buffer)
-{
- if (!atomic_dec_and_test(&buffer->refcount))
- return;
-
- call_rcu(&buffer->rcu_head, perf_buffer_free_rcu);
-}
-
-static void perf_mmap_open(struct vm_area_struct *vma)
-{
- struct perf_event *event = vma->vm_file->private_data;
-
- atomic_inc(&event->mmap_count);
-}
-
-static void perf_mmap_close(struct vm_area_struct *vma)
-{
- struct perf_event *event = vma->vm_file->private_data;
-
- if (atomic_dec_and_mutex_lock(&event->mmap_count, &event->mmap_mutex)) {
- unsigned long size = perf_data_size(event->buffer);
- struct user_struct *user = event->mmap_user;
- struct perf_buffer *buffer = event->buffer;
-
- atomic_long_sub((size >> PAGE_SHIFT) + 1, &user->locked_vm);
- vma->vm_mm->locked_vm -= event->mmap_locked;
- rcu_assign_pointer(event->buffer, NULL);
- mutex_unlock(&event->mmap_mutex);
-
- perf_buffer_put(buffer);
- free_uid(user);
- }
-}
-
-static const struct vm_operations_struct perf_mmap_vmops = {
- .open = perf_mmap_open,
- .close = perf_mmap_close,
- .fault = perf_mmap_fault,
- .page_mkwrite = perf_mmap_fault,
-};
-
-static int perf_mmap(struct file *file, struct vm_area_struct *vma)
-{
- struct perf_event *event = file->private_data;
- unsigned long user_locked, user_lock_limit;
- struct user_struct *user = current_user();
- unsigned long locked, lock_limit;
- struct perf_buffer *buffer;
- unsigned long vma_size;
- unsigned long nr_pages;
- long user_extra, extra;
- int ret = 0, flags = 0;
-
- /*
- * Don't allow mmap() of inherited per-task counters. This would
- * create a performance issue due to all children writing to the
- * same buffer.
- */
- if (event->cpu == -1 && event->attr.inherit)
- return -EINVAL;
-
- if (!(vma->vm_flags & VM_SHARED))
- return -EINVAL;
-
- vma_size = vma->vm_end - vma->vm_start;
- nr_pages = (vma_size / PAGE_SIZE) - 1;
-
- /*
- * If we have buffer 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->buffer) {
- if (event->buffer->nr_pages == nr_pages)
- atomic_inc(&event->buffer->refcount);
- else
- ret = -EINVAL;
- goto unlock;
- }
-
- user_extra = nr_pages + 1;
- user_lock_limit = sysctl_perf_event_mlock >> (PAGE_SHIFT - 10);
-
- /*
- * Increase the limit linearly with more CPUs:
- */
- user_lock_limit *= num_online_cpus();
-
- user_locked = atomic_long_read(&user->locked_vm) + user_extra;
-
- extra = 0;
- if (user_locked > user_lock_limit)
- extra = user_locked - user_lock_limit;
-
- lock_limit = rlimit(RLIMIT_MEMLOCK);
- lock_limit >>= PAGE_SHIFT;
- locked = vma->vm_mm->locked_vm + extra;
-
- if ((locked > lock_limit) && perf_paranoid_tracepoint_raw() &&
- !capable(CAP_IPC_LOCK)) {
- ret = -EPERM;
- goto unlock;
- }
-
- WARN_ON(event->buffer);
-
- if (vma->vm_flags & VM_WRITE)
- flags |= PERF_BUFFER_WRITABLE;
-
- buffer = perf_buffer_alloc(nr_pages, event->attr.wakeup_watermark,
- event->cpu, flags);
- if (!buffer) {
- ret = -ENOMEM;
- goto unlock;
- }
- rcu_assign_pointer(event->buffer, buffer);
-
- atomic_long_add(user_extra, &user->locked_vm);
- event->mmap_locked = extra;
- event->mmap_user = get_current_user();
- vma->vm_mm->locked_vm += event->mmap_locked;
-
-unlock:
- if (!ret)
- atomic_inc(&event->mmap_count);
- mutex_unlock(&event->mmap_mutex);
-
- vma->vm_flags |= VM_RESERVED;
- vma->vm_ops = &perf_mmap_vmops;
-
- return ret;
-}
-
-static int perf_fasync(int fd, struct file *filp, int on)
-{
- struct inode *inode = filp->f_path.dentry->d_inode;
- struct perf_event *event = filp->private_data;
- int retval;
-
- mutex_lock(&inode->i_mutex);
- retval = fasync_helper(fd, filp, on, &event->fasync);
- mutex_unlock(&inode->i_mutex);
-
- if (retval < 0)
- return retval;
-
- return 0;
-}
-
-static const struct file_operations perf_fops = {
- .llseek = no_llseek,
- .release = perf_release,
- .read = perf_read,
- .poll = perf_poll,
- .unlocked_ioctl = perf_ioctl,
- .compat_ioctl = perf_ioctl,
- .mmap = perf_mmap,
- .fasync = perf_fasync,
-};
-
-/*
- * Perf event wakeup
- *
- * If there's data, ensure we set the poll() state and publish everything
- * to user-space before waking everybody up.
- */
-
-void perf_event_wakeup(struct perf_event *event)
-{
- wake_up_all(&event->waitq);
-
- if (event->pending_kill) {
- kill_fasync(&event->fasync, SIGIO, event->pending_kill);
- event->pending_kill = 0;
- }
-}
-
-/*
- * Pending wakeups
- *
- * Handle the case where we need to wakeup up from NMI (or rq->lock) context.
- *
- * The NMI bit means we cannot possibly take locks. Therefore, maintain a
- * single linked list and use cmpxchg() to add entries lockless.
- */
-
-static void perf_pending_event(struct perf_pending_entry *entry)
-{
- struct perf_event *event = container_of(entry,
- struct perf_event, pending);
-
- if (event->pending_disable) {
- event->pending_disable = 0;
- __perf_event_disable(event);
- }
-
- if (event->pending_wakeup) {
- event->pending_wakeup = 0;
- perf_event_wakeup(event);
- }
-}
-
-#define PENDING_TAIL ((struct perf_pending_entry *)-1UL)
-
-static DEFINE_PER_CPU(struct perf_pending_entry *, perf_pending_head) = {
- PENDING_TAIL,
-};
-
-static void perf_pending_queue(struct perf_pending_entry *entry,
- void (*func)(struct perf_pending_entry *))
-{
- struct perf_pending_entry **head;
-
- if (cmpxchg(&entry->next, NULL, PENDING_TAIL) != NULL)
- return;
-
- entry->func = func;
-
- head = &get_cpu_var(perf_pending_head);
-
- do {
- entry->next = *head;
- } while (cmpxchg(head, entry->next, entry) != entry->next);
-
- set_perf_event_pending();
-
- put_cpu_var(perf_pending_head);
-}
-
-static int __perf_pending_run(void)
-{
- struct perf_pending_entry *list;
- int nr = 0;
-
- list = xchg(&__get_cpu_var(perf_pending_head), PENDING_TAIL);
- while (list != PENDING_TAIL) {
- void (*func)(struct perf_pending_entry *);
- struct perf_pending_entry *entry = list;
-
- list = list->next;
-
- func = entry->func;
- entry->next = NULL;
- /*
- * Ensure we observe the unqueue before we issue the wakeup,
- * so that we won't be waiting forever.
- * -- see perf_not_pending().
- */
- smp_wmb();
-
- func(entry);
- nr++;
- }
-
- return nr;
-}
-
-static inline int perf_not_pending(struct perf_event *event)
-{
- /*
- * If we flush on whatever cpu we run, there is a chance we don't
- * need to wait.
- */
- get_cpu();
- __perf_pending_run();
- put_cpu();
-
- /*
- * Ensure we see the proper queue state before going to sleep
- * so that we do not miss the wakeup. -- see perf_pending_handle()
- */
- smp_rmb();
- return event->pending.next == NULL;
-}
-
-static void perf_pending_sync(struct perf_event *event)
-{
- wait_event(event->waitq, perf_not_pending(event));
-}
-
-void perf_event_do_pending(void)
-{
- __perf_pending_run();
-}
-
-/*
- * Callchain support -- arch specific
- */
-
-__weak struct perf_callchain_entry *perf_callchain(struct pt_regs *regs)
-{
- return NULL;
-}
-
-
-/*
- * We assume there is only KVM supporting the callbacks.
- * Later on, we might change it to a list if there is
- * another virtualization implementation supporting the callbacks.
- */
-struct perf_guest_info_callbacks *perf_guest_cbs;
-
-int perf_register_guest_info_callbacks(struct perf_guest_info_callbacks *cbs)
-{
- perf_guest_cbs = cbs;
- return 0;
-}
-EXPORT_SYMBOL_GPL(perf_register_guest_info_callbacks);
-
-int perf_unregister_guest_info_callbacks(struct perf_guest_info_callbacks *cbs)
-{
- perf_guest_cbs = NULL;
- return 0;
-}
-EXPORT_SYMBOL_GPL(perf_unregister_guest_info_callbacks);
-
-/*
- * Output
- */
-static bool perf_output_space(struct perf_buffer *buffer, unsigned long tail,
- unsigned long offset, unsigned long head)
-{
- unsigned long mask;
-
- if (!buffer->writable)
- return true;
-
- mask = perf_data_size(buffer) - 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->buffer->poll, POLL_IN);
-
- if (handle->nmi) {
- handle->event->pending_wakeup = 1;
- perf_pending_queue(&handle->event->pending,
- perf_pending_event);
- } else
- perf_event_wakeup(handle->event);
-}
-
-/*
- * We need to ensure a later event_id doesn't publish a head when a former
- * event isn't done writing. However since we need to deal with NMIs we
- * cannot fully serialize things.
- *
- * We only publish the head (and generate a wakeup) when the outer-most
- * event completes.
- */
-static void perf_output_get_handle(struct perf_output_handle *handle)
-{
- struct perf_buffer *buffer = handle->buffer;
-
- preempt_disable();
- local_inc(&buffer->nest);
- handle->wakeup = local_read(&buffer->wakeup);
-}
-
-static void perf_output_put_handle(struct perf_output_handle *handle)
-{
- struct perf_buffer *buffer = handle->buffer;
- unsigned long head;
-
-again:
- head = local_read(&buffer->head);
-
- /*
- * IRQ/NMI can happen here, which means we can miss a head update.
- */
-
- if (!local_dec_and_test(&buffer->nest))
- goto out;
-
- /*
- * Publish the known good head. Rely on the full barrier implied
- * by atomic_dec_and_test() order the buffer->head read and this
- * write.
- */
- buffer->user_page->data_head = head;
-
- /*
- * Now check if we missed an update, rely on the (compiler)
- * barrier in atomic_dec_and_test() to re-read buffer->head.
- */
- if (unlikely(head != local_read(&buffer->head))) {
- local_inc(&buffer->nest);
- goto again;
- }
-
- if (handle->wakeup != local_read(&buffer->wakeup))
- perf_output_wakeup(handle);
-
- out:
- preempt_enable();
-}
-
-__always_inline void perf_output_copy(struct perf_output_handle *handle,
- const void *buf, unsigned int len)
-{
- do {
- unsigned long size = min_t(unsigned long, handle->size, len);
-
- memcpy(handle->addr, buf, size);
-
- len -= size;
- handle->addr += size;
- buf += size;
- handle->size -= size;
- if (!handle->size) {
- struct perf_buffer *buffer = handle->buffer;
-
- handle->page++;
- handle->page &= buffer->nr_pages - 1;
- handle->addr = buffer->data_pages[handle->page];
- handle->size = PAGE_SIZE << page_order(buffer);
- }
- } while (len);
-}
-
-int perf_output_begin(struct perf_output_handle *handle,
- struct perf_event *event, unsigned int size,
- int nmi, int sample)
-{
- struct perf_buffer *buffer;
- 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;
-
- buffer = rcu_dereference(event->buffer);
- if (!buffer)
- goto out;
-
- handle->buffer = buffer;
- handle->event = event;
- handle->nmi = nmi;
- handle->sample = sample;
-
- if (!buffer->nr_pages)
- goto out;
-
- have_lost = local_read(&buffer->lost);
- if (have_lost)
- size += sizeof(lost_event);
-
- perf_output_get_handle(handle);
-
- do {
- /*
- * Userspace could choose to issue a mb() before updating the
- * tail pointer. So that all reads will be completed before the
- * write is issued.
- */
- tail = ACCESS_ONCE(buffer->user_page->data_tail);
- smp_rmb();
- offset = head = local_read(&buffer->head);
- head += size;
- if (unlikely(!perf_output_space(buffer, tail, offset, head)))
- goto fail;
- } while (local_cmpxchg(&buffer->head, offset, head) != offset);
-
- if (head - local_read(&buffer->wakeup) > buffer->watermark)
- local_add(buffer->watermark, &buffer->wakeup);
-
- handle->page = offset >> (PAGE_SHIFT + page_order(buffer));
- handle->page &= buffer->nr_pages - 1;
- handle->size = offset & ((PAGE_SIZE << page_order(buffer)) - 1);
- handle->addr = buffer->data_pages[handle->page];
- handle->addr += handle->size;
- handle->size = (PAGE_SIZE << page_order(buffer)) - handle->size;
-
- if (have_lost) {
- lost_event.header.type = PERF_RECORD_LOST;
- lost_event.header.misc = 0;
- lost_event.header.size = sizeof(lost_event);
- lost_event.id = event->id;
- lost_event.lost = local_xchg(&buffer->lost, 0);
-
- perf_output_put(handle, lost_event);
- }
-
- return 0;
-
-fail:
- local_inc(&buffer->lost);
- perf_output_put_handle(handle);
-out:
- rcu_read_unlock();
-
- return -ENOSPC;
-}
-
-void perf_output_end(struct perf_output_handle *handle)
-{
- struct perf_event *event = handle->event;
- struct perf_buffer *buffer = handle->buffer;
-
- int wakeup_events = event->attr.wakeup_events;
-
- if (handle->sample && wakeup_events) {
- int events = local_inc_return(&buffer->events);
- if (events >= wakeup_events) {
- local_sub(wakeup_events, &buffer->events);
- local_inc(&buffer->wakeup);
- }
- }
-
- perf_output_put_handle(handle);
- rcu_read_unlock();
-}
-
-static u32 perf_event_pid(struct perf_event *event, struct task_struct *p)
-{
- /*
- * only top level events have the pid namespace they were created in
- */
- if (event->parent)
- event = event->parent;
-
- return task_tgid_nr_ns(p, event->ns);
-}
-
-static u32 perf_event_tid(struct perf_event *event, struct task_struct *p)
-{
- /*
- * only top level events have the pid namespace they were created in
- */
- if (event->parent)
- event = event->parent;
-
- return task_pid_nr_ns(p, event->ns);
-}
-
-static void perf_output_read_one(struct perf_output_handle *handle,
- struct perf_event *event)
-{
- u64 read_format = event->attr.read_format;
- u64 values[4];
- int n = 0;
-
- values[n++] = perf_event_count(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);
-
- 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++] = perf_event_count(leader);
- 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++] = perf_event_count(sub);
- if (read_format & PERF_FORMAT_ID)
- values[n++] = primary_event_id(sub);
-
- perf_output_copy(handle, values, n * sizeof(u64));
- }
-}
-
-static void perf_output_read(struct perf_output_handle *handle,
- struct perf_event *event)
-{
- if (event->attr.read_format & PERF_FORMAT_GROUP)
- perf_output_read_group(handle, event);
- else
- perf_output_read_one(handle, event);
-}
-
-void perf_output_sample(struct perf_output_handle *handle,
- struct perf_event_header *header,
- struct perf_sample_data *data,
- struct perf_event *event)
-{
- u64 sample_type = data->type;
-
- perf_output_put(handle, *header);
-
- if (sample_type & PERF_SAMPLE_IP)
- perf_output_put(handle, data->ip);
-
- if (sample_type & PERF_SAMPLE_TID)
- perf_output_put(handle, data->tid_entry);
-
- if (sample_type & PERF_SAMPLE_TIME)
- perf_output_put(handle, data->time);
-
- if (sample_type & PERF_SAMPLE_ADDR)
- perf_output_put(handle, data->addr);
-
- if (sample_type & PERF_SAMPLE_ID)
- perf_output_put(handle, data->id);
-
- if (sample_type & PERF_SAMPLE_STREAM_ID)
- perf_output_put(handle, data->stream_id);
-
- if (sample_type & PERF_SAMPLE_CPU)
- perf_output_put(handle, data->cpu_entry);
-
- if (sample_type & PERF_SAMPLE_PERIOD)
- perf_output_put(handle, data->period);
-
- if (sample_type & PERF_SAMPLE_READ)
- perf_output_read(handle, event);
-
- if (sample_type & PERF_SAMPLE_CALLCHAIN) {
- if (data->callchain) {
- int size = 1;
-
- if (data->callchain)
- size += data->callchain->nr;
-
- size *= sizeof(u64);
-
- perf_output_copy(handle, data->callchain, size);
- } else {
- u64 nr = 0;
- perf_output_put(handle, nr);
- }
- }
-
- if (sample_type & PERF_SAMPLE_RAW) {
- if (data->raw) {
- perf_output_put(handle, data->raw->size);
- perf_output_copy(handle, data->raw->data,
- data->raw->size);
- } else {
- struct {
- u32 size;
- u32 data;
- } raw = {
- .size = sizeof(u32),
- .data = 0,
- };
- perf_output_put(handle, raw);
- }
- }
-}
-
-void perf_prepare_sample(struct perf_event_header *header,
- struct perf_sample_data *data,
- struct perf_event *event,
- struct pt_regs *regs)
-{
- u64 sample_type = event->attr.sample_type;
-
- data->type = sample_type;
-
- header->type = PERF_RECORD_SAMPLE;
- header->size = sizeof(*header);
-
- header->misc = 0;
- header->misc |= perf_misc_flags(regs);
-
- if (sample_type & PERF_SAMPLE_IP) {
- data->ip = perf_instruction_pointer(regs);
-
- header->size += sizeof(data->ip);
- }
-
- if (sample_type & PERF_SAMPLE_TID) {
- /* namespace issues */
- data->tid_entry.pid = perf_event_pid(event, current);
- data->tid_entry.tid = perf_event_tid(event, current);
-
- header->size += sizeof(data->tid_entry);
- }
-
- if (sample_type & PERF_SAMPLE_TIME) {
- data->time = perf_clock();
-
- header->size += sizeof(data->time);
- }
-
- if (sample_type & PERF_SAMPLE_ADDR)
- header->size += sizeof(data->addr);
-
- if (sample_type & PERF_SAMPLE_ID) {
- data->id = primary_event_id(event);
-
- header->size += sizeof(data->id);
- }
-
- if (sample_type & PERF_SAMPLE_STREAM_ID) {
- data->stream_id = event->id;
-
- header->size += sizeof(data->stream_id);
- }
-
- if (sample_type & PERF_SAMPLE_CPU) {
- data->cpu_entry.cpu = raw_smp_processor_id();
- data->cpu_entry.reserved = 0;
-
- header->size += sizeof(data->cpu_entry);
- }
-
- if (sample_type & PERF_SAMPLE_PERIOD)
- header->size += sizeof(data->period);
-
- if (sample_type & PERF_SAMPLE_READ)
- header->size += perf_event_read_size(event);
-
- if (sample_type & PERF_SAMPLE_CALLCHAIN) {
- int size = 1;
-
- data->callchain = perf_callchain(regs);
-
- if (data->callchain)
- size += data->callchain->nr;
-
- header->size += size * sizeof(u64);
- }
-
- if (sample_type & PERF_SAMPLE_RAW) {
- int size = sizeof(u32);
-
- if (data->raw)
- size += data->raw->size;
- else
- size += sizeof(u32);
-
- WARN_ON_ONCE(size & (sizeof(u64)-1));
- header->size += size;
- }
-}
-
-static void perf_event_output(struct perf_event *event, int nmi,
- struct perf_sample_data *data,
- struct pt_regs *regs)
-{
- struct perf_output_handle handle;
- struct perf_event_header header;
-
- perf_prepare_sample(&header, data, event, regs);
-
- if (perf_output_begin(&handle, event, header.size, nmi, 1))
- return;
-
- perf_output_sample(&handle, &header, data, event);
-
- perf_output_end(&handle);
-}
-
-/*
- * read event_id
- */
-
-struct perf_read_event {
- struct perf_event_header header;
-
- u32 pid;
- u32 tid;
-};
-
-static void
-perf_event_read_event(struct perf_event *event,
- struct task_struct *task)
-{
- struct perf_output_handle handle;
- struct perf_read_event read_event = {
- .header = {
- .type = PERF_RECORD_READ,
- .misc = 0,
- .size = sizeof(read_event) + perf_event_read_size(event),
- },
- .pid = perf_event_pid(event, task),
- .tid = perf_event_tid(event, task),
- };
- int ret;
-
- ret = perf_output_begin(&handle, event, read_event.header.size, 0, 0);
- if (ret)
- return;
-
- perf_output_put(&handle, read_event);
- perf_output_read(&handle, event);
-
- perf_output_end(&handle);
-}
-
-/*
- * task tracking -- fork/exit
- *
- * enabled by: attr.comm | attr.mmap | attr.mmap_data | attr.task
- */
-
-struct perf_task_event {
- struct task_struct *task;
- struct perf_event_context *task_ctx;
-
- struct {
- struct perf_event_header header;
-
- u32 pid;
- u32 ppid;
- u32 tid;
- u32 ptid;
- u64 time;
- } event_id;
-};
-
-static void perf_event_task_output(struct perf_event *event,
- struct perf_task_event *task_event)
-{
- struct perf_output_handle handle;
- struct task_struct *task = task_event->task;
- int size, ret;
-
- size = task_event->event_id.header.size;
- ret = perf_output_begin(&handle, event, size, 0, 0);
-
- if (ret)
- return;
-
- task_event->event_id.pid = perf_event_pid(event, task);
- task_event->event_id.ppid = perf_event_pid(event, current);
-
- task_event->event_id.tid = perf_event_tid(event, task);
- task_event->event_id.ptid = perf_event_tid(event, current);
-
- perf_output_put(&handle, task_event->event_id);
-
- perf_output_end(&handle);
-}
-
-static int perf_event_task_match(struct perf_event *event)
-{
- if (event->state < PERF_EVENT_STATE_INACTIVE)
- return 0;
-
- if (event->cpu != -1 && event->cpu != smp_processor_id())
- return 0;
-
- if (event->attr.comm || event->attr.mmap ||
- event->attr.mmap_data || event->attr.task)
- return 1;
-
- return 0;
-}
-
-static void perf_event_task_ctx(struct perf_event_context *ctx,
- struct perf_task_event *task_event)
-{
- struct perf_event *event;
-
- list_for_each_entry_rcu(event, &ctx->event_list, event_entry) {
- if (perf_event_task_match(event))
- perf_event_task_output(event, task_event);
- }
-}
-
-static void perf_event_task_event(struct perf_task_event *task_event)
-{
- struct perf_cpu_context *cpuctx;
- struct perf_event_context *ctx = task_event->task_ctx;
-
- rcu_read_lock();
- cpuctx = &get_cpu_var(perf_cpu_context);
- perf_event_task_ctx(&cpuctx->ctx, task_event);
- if (!ctx)
- ctx = rcu_dereference(current->perf_event_ctxp);
- if (ctx)
- perf_event_task_ctx(ctx, task_event);
- put_cpu_var(perf_cpu_context);
- rcu_read_unlock();
-}
-
-static void perf_event_task(struct task_struct *task,
- struct perf_event_context *task_ctx,
- int new)
-{
- struct perf_task_event task_event;
-
- if (!atomic_read(&nr_comm_events) &&
- !atomic_read(&nr_mmap_events) &&
- !atomic_read(&nr_task_events))
- return;
-
- task_event = (struct perf_task_event){
- .task = task,
- .task_ctx = task_ctx,
- .event_id = {
- .header = {
- .type = new ? PERF_RECORD_FORK : PERF_RECORD_EXIT,
- .misc = 0,
- .size = sizeof(task_event.event_id),
- },
- /* .pid */
- /* .ppid */
- /* .tid */
- /* .ptid */
- .time = perf_clock(),
- },
- };
-
- perf_event_task_event(&task_event);
-}
-
-void perf_event_fork(struct task_struct *task)
-{
- perf_event_task(task, NULL, 1);
-}
-
-/*
- * comm tracking
- */
-
-struct perf_comm_event {
- struct task_struct *task;
- char *comm;
- int comm_size;
-
- struct {
- struct perf_event_header header;
-
- u32 pid;
- u32 tid;
- } event_id;
-};
-
-static void perf_event_comm_output(struct perf_event *event,
- struct perf_comm_event *comm_event)
-{
- struct perf_output_handle handle;
- int size = comm_event->event_id.header.size;
- int ret = perf_output_begin(&handle, event, size, 0, 0);
-
- if (ret)
- return;
-
- comm_event->event_id.pid = perf_event_pid(event, comm_event->task);
- comm_event->event_id.tid = perf_event_tid(event, comm_event->task);
-
- perf_output_put(&handle, comm_event->event_id);
- perf_output_copy(&handle, comm_event->comm,
- comm_event->comm_size);
- perf_output_end(&handle);
-}
-
-static int perf_event_comm_match(struct perf_event *event)
-{
- if (event->state < PERF_EVENT_STATE_INACTIVE)
- return 0;
-
- if (event->cpu != -1 && event->cpu != smp_processor_id())
- return 0;
-
- if (event->attr.comm)
- return 1;
-
- return 0;
-}
-
-static void perf_event_comm_ctx(struct perf_event_context *ctx,
- struct perf_comm_event *comm_event)
-{
- struct perf_event *event;
-
- list_for_each_entry_rcu(event, &ctx->event_list, event_entry) {
- if (perf_event_comm_match(event))
- perf_event_comm_output(event, comm_event);
- }
-}
-
-static void perf_event_comm_event(struct perf_comm_event *comm_event)
-{
- struct perf_cpu_context *cpuctx;
- struct perf_event_context *ctx;
- unsigned int size;
- char comm[TASK_COMM_LEN];
-
- memset(comm, 0, sizeof(comm));
- strlcpy(comm, comm_event->task->comm, sizeof(comm));
- size = ALIGN(strlen(comm)+1, sizeof(u64));
-
- comm_event->comm = comm;
- comm_event->comm_size = size;
-
- comm_event->event_id.header.size = sizeof(comm_event->event_id) + size;
-
- rcu_read_lock();
- cpuctx = &get_cpu_var(perf_cpu_context);
- perf_event_comm_ctx(&cpuctx->ctx, comm_event);
- ctx = rcu_dereference(current->perf_event_ctxp);
- if (ctx)
- perf_event_comm_ctx(ctx, comm_event);
- put_cpu_var(perf_cpu_context);
- rcu_read_unlock();
-}
-
-void perf_event_comm(struct task_struct *task)
-{
- struct perf_comm_event comm_event;
-
- if (task->perf_event_ctxp)
- perf_event_enable_on_exec(task);
-
- if (!atomic_read(&nr_comm_events))
- return;
-
- comm_event = (struct perf_comm_event){
- .task = task,
- /* .comm */
- /* .comm_size */
- .event_id = {
- .header = {
- .type = PERF_RECORD_COMM,
- .misc = 0,
- /* .size */
- },
- /* .pid */
- /* .tid */
- },
- };
-
- perf_event_comm_event(&comm_event);
-}
-
-/*
- * mmap tracking
- */
-
-struct perf_mmap_event {
- struct vm_area_struct *vma;
-
- const char *file_name;
- int file_size;
-
- struct {
- struct perf_event_header header;
-
- u32 pid;
- u32 tid;
- u64 start;
- u64 len;
- u64 pgoff;
- } event_id;
-};
-
-static void perf_event_mmap_output(struct perf_event *event,
- struct perf_mmap_event *mmap_event)
-{
- struct perf_output_handle handle;
- int size = mmap_event->event_id.header.size;
- int ret = perf_output_begin(&handle, event, size, 0, 0);
-
- if (ret)
- return;
-
- mmap_event->event_id.pid = perf_event_pid(event, current);
- mmap_event->event_id.tid = perf_event_tid(event, current);
-
- perf_output_put(&handle, mmap_event->event_id);
- perf_output_copy(&handle, mmap_event->file_name,
- mmap_event->file_size);
- perf_output_end(&handle);
-}
-
-static int perf_event_mmap_match(struct perf_event *event,
- struct perf_mmap_event *mmap_event,
- int executable)
-{
- if (event->state < PERF_EVENT_STATE_INACTIVE)
- return 0;
-
- if (event->cpu != -1 && event->cpu != smp_processor_id())
- return 0;
-
- if ((!executable && event->attr.mmap_data) ||
- (executable && event->attr.mmap))
- return 1;
-
- return 0;
-}
-
-static void perf_event_mmap_ctx(struct perf_event_context *ctx,
- struct perf_mmap_event *mmap_event,
- int executable)
-{
- struct perf_event *event;
-
- list_for_each_entry_rcu(event, &ctx->event_list, event_entry) {
- if (perf_event_mmap_match(event, mmap_event, executable))
- perf_event_mmap_output(event, mmap_event);
- }
-}
-
-static void perf_event_mmap_event(struct perf_mmap_event *mmap_event)
-{
- struct perf_cpu_context *cpuctx;
- struct perf_event_context *ctx;
- struct vm_area_struct *vma = mmap_event->vma;
- struct file *file = vma->vm_file;
- unsigned int size;
- char tmp[16];
- char *buf = NULL;
- const char *name;
-
- memset(tmp, 0, sizeof(tmp));
-
- if (file) {
- /*
- * d_path works from the end of the buffer backwards, so we
- * need to add enough zero bytes after the string to handle
- * the 64bit alignment we do later.
- */
- buf = kzalloc(PATH_MAX + sizeof(u64), GFP_KERNEL);
- if (!buf) {
- name = strncpy(tmp, "//enomem", sizeof(tmp));
- goto got_name;
- }
- name = d_path(&file->f_path, buf, PATH_MAX);
- if (IS_ERR(name)) {
- name = strncpy(tmp, "//toolong", sizeof(tmp));
- goto got_name;
- }
- } else {
- if (arch_vma_name(mmap_event->vma)) {
- name = strncpy(tmp, arch_vma_name(mmap_event->vma),
- sizeof(tmp));
- goto got_name;
- }
-
- if (!vma->vm_mm) {
- name = strncpy(tmp, "[vdso]", sizeof(tmp));
- goto got_name;
- } else if (vma->vm_start <= vma->vm_mm->start_brk &&
- vma->vm_end >= vma->vm_mm->brk) {
- name = strncpy(tmp, "[heap]", sizeof(tmp));
- goto got_name;
- } else if (vma->vm_start <= vma->vm_mm->start_stack &&
- vma->vm_end >= vma->vm_mm->start_stack) {
- name = strncpy(tmp, "[stack]", sizeof(tmp));
- goto got_name;
- }
-
- name = strncpy(tmp, "//anon", sizeof(tmp));
- goto got_name;
- }
-
-got_name:
- size = ALIGN(strlen(name)+1, sizeof(u64));
-
- mmap_event->file_name = name;
- mmap_event->file_size = size;
-
- mmap_event->event_id.header.size = sizeof(mmap_event->event_id) + size;
-
- rcu_read_lock();
- cpuctx = &get_cpu_var(perf_cpu_context);
- perf_event_mmap_ctx(&cpuctx->ctx, mmap_event, vma->vm_flags & VM_EXEC);
- ctx = rcu_dereference(current->perf_event_ctxp);
- if (ctx)
- perf_event_mmap_ctx(ctx, mmap_event, vma->vm_flags & VM_EXEC);
- put_cpu_var(perf_cpu_context);
- rcu_read_unlock();
-
- kfree(buf);
-}
-
-void perf_event_mmap(struct vm_area_struct *vma)
-{
- struct perf_mmap_event mmap_event;
-
- if (!atomic_read(&nr_mmap_events))
- return;
-
- mmap_event = (struct perf_mmap_event){
- .vma = vma,
- /* .file_name */
- /* .file_size */
- .event_id = {
- .header = {
- .type = PERF_RECORD_MMAP,
- .misc = PERF_RECORD_MISC_USER,
- /* .size */
- },
- /* .pid */
- /* .tid */
- .start = vma->vm_start,
- .len = vma->vm_end - vma->vm_start,
- .pgoff = (u64)vma->vm_pgoff << PAGE_SHIFT,
- },
- };
-
- perf_event_mmap_event(&mmap_event);
-}
-
-/*
- * IRQ throttle logging
- */
-
-static void perf_log_throttle(struct perf_event *event, int enable)
-{
- struct perf_output_handle handle;
- int ret;
-
- struct {
- struct perf_event_header header;
- u64 time;
- u64 id;
- u64 stream_id;
- } throttle_event = {
- .header = {
- .type = PERF_RECORD_THROTTLE,
- .misc = 0,
- .size = sizeof(throttle_event),
- },
- .time = perf_clock(),
- .id = primary_event_id(event),
- .stream_id = event->id,
- };
-
- if (enable)
- throttle_event.header.type = PERF_RECORD_UNTHROTTLE;
-
- ret = perf_output_begin(&handle, event, sizeof(throttle_event), 1, 0);
- if (ret)
- return;
-
- perf_output_put(&handle, throttle_event);
- perf_output_end(&handle);
-}
-
-/*
- * Generic event overflow handling, sampling.
- */
-
-static int __perf_event_overflow(struct perf_event *event, int nmi,
- int throttle, struct perf_sample_data *data,
- struct pt_regs *regs)
-{
- int events = atomic_read(&event->event_limit);
- struct hw_perf_event *hwc = &event->hw;
- int ret = 0;
-
- throttle = (throttle && event->pmu->unthrottle != NULL);
-
- if (!throttle) {
- hwc->interrupts++;
- } else {
- if (hwc->interrupts != MAX_INTERRUPTS) {
- hwc->interrupts++;
- if (HZ * hwc->interrupts >
- (u64)sysctl_perf_event_sample_rate) {
- hwc->interrupts = MAX_INTERRUPTS;
- perf_log_throttle(event, 0);
- ret = 1;
- }
- } else {
- /*
- * Keep re-disabling events even though on the previous
- * pass we disabled it - just in case we raced with a
- * sched-in and the event got enabled again:
- */
- ret = 1;
- }
- }
-
- if (event->attr.freq) {
- u64 now = perf_clock();
- s64 delta = now - hwc->freq_time_stamp;
-
- hwc->freq_time_stamp = now;
-
- if (delta > 0 && delta < 2*TICK_NSEC)
- perf_adjust_period(event, delta, hwc->last_period);
- }
-
- /*
- * XXX event_limit might not quite work as expected on inherited
- * events
- */
-
- event->pending_kill = POLL_IN;
- if (events && atomic_dec_and_test(&event->event_limit)) {
- ret = 1;
- event->pending_kill = POLL_HUP;
- if (nmi) {
- event->pending_disable = 1;
- perf_pending_queue(&event->pending,
- perf_pending_event);
- } else
- perf_event_disable(event);
- }
-
- if (event->overflow_handler)
- event->overflow_handler(event, nmi, data, regs);
- else
- perf_event_output(event, nmi, data, regs);
-
- return ret;
-}
-
-int perf_event_overflow(struct perf_event *event, int nmi,
- struct perf_sample_data *data,
- struct pt_regs *regs)
-{
- return __perf_event_overflow(event, nmi, 1, data, regs);
-}
-
-/*
- * Generic software event infrastructure
- */
-
-/*
- * We directly increment event->count and keep a second value in
- * event->hw.period_left to count intervals. This period event
- * is kept in the range [-sample_period, 0] so that we can use the
- * sign as trigger.
- */
-
-static u64 perf_swevent_set_period(struct perf_event *event)
-{
- struct hw_perf_event *hwc = &event->hw;
- u64 period = hwc->last_period;
- u64 nr, offset;
- s64 old, val;
-
- hwc->last_period = hwc->sample_period;
-
-again:
- old = val = local64_read(&hwc->period_left);
- if (val < 0)
- return 0;
-
- nr = div64_u64(period + val, period);
- offset = nr * period;
- val -= offset;
- if (local64_cmpxchg(&hwc->period_left, old, val) != old)
- goto again;
-
- return nr;
-}
-
-static void perf_swevent_overflow(struct perf_event *event, u64 overflow,
- int nmi, struct perf_sample_data *data,
- struct pt_regs *regs)
-{
- struct hw_perf_event *hwc = &event->hw;
- int throttle = 0;
-
- data->period = event->hw.last_period;
- if (!overflow)
- overflow = perf_swevent_set_period(event);
-
- if (hwc->interrupts == MAX_INTERRUPTS)
- return;
-
- for (; overflow; overflow--) {
- if (__perf_event_overflow(event, nmi, throttle,
- data, regs)) {
- /*
- * We inhibit the overflow from happening when
- * hwc->interrupts == MAX_INTERRUPTS.
- */
- break;
- }
- throttle = 1;
- }
-}
-
-static void perf_swevent_add(struct perf_event *event, u64 nr,
- int nmi, struct perf_sample_data *data,
- struct pt_regs *regs)
-{
- struct hw_perf_event *hwc = &event->hw;
-
- local64_add(nr, &event->count);
-
- if (!regs)
- return;
-
- if (!hwc->sample_period)
- return;
-
- if (nr == 1 && hwc->sample_period == 1 && !event->attr.freq)
- return perf_swevent_overflow(event, 1, nmi, data, regs);
-
- if (local64_add_negative(nr, &hwc->period_left))
- return;
-
- perf_swevent_overflow(event, 0, nmi, data, regs);
-}
-
-static int perf_exclude_event(struct perf_event *event,
- struct pt_regs *regs)
-{
- if (regs) {
- if (event->attr.exclude_user && user_mode(regs))
- return 1;
-
- if (event->attr.exclude_kernel && !user_mode(regs))
- return 1;
- }
-
- return 0;
-}
-
-static int perf_swevent_match(struct perf_event *event,
- enum perf_type_id type,
- u32 event_id,
- struct perf_sample_data *data,
- struct pt_regs *regs)
-{
- if (event->attr.type != type)
- return 0;
-
- if (event->attr.config != event_id)
- return 0;
-
- if (perf_exclude_event(event, regs))
- return 0;
-
- return 1;
-}
-
-static inline u64 swevent_hash(u64 type, u32 event_id)
-{
- u64 val = event_id | (type << 32);
-
- return hash_64(val, SWEVENT_HLIST_BITS);
-}
-
-static inline struct hlist_head *
-__find_swevent_head(struct swevent_hlist *hlist, u64 type, u32 event_id)
-{
- u64 hash = swevent_hash(type, event_id);
-
- return &hlist->heads[hash];
-}
-
-/* For the read side: events when they trigger */
-static inline struct hlist_head *
-find_swevent_head_rcu(struct perf_cpu_context *ctx, u64 type, u32 event_id)
-{
- struct swevent_hlist *hlist;
-
- hlist = rcu_dereference(ctx->swevent_hlist);
- if (!hlist)
- return NULL;
-
- return __find_swevent_head(hlist, type, event_id);
-}
-
-/* For the event head insertion and removal in the hlist */
-static inline struct hlist_head *
-find_swevent_head(struct perf_cpu_context *ctx, struct perf_event *event)
-{
- struct swevent_hlist *hlist;
- u32 event_id = event->attr.config;
- u64 type = event->attr.type;
-
- /*
- * Event scheduling is always serialized against hlist allocation
- * and release. Which makes the protected version suitable here.
- * The context lock guarantees that.
- */
- hlist = rcu_dereference_protected(ctx->swevent_hlist,
- lockdep_is_held(&event->ctx->lock));
- if (!hlist)
- return NULL;
-
- return __find_swevent_head(hlist, type, event_id);
-}
-
-static void do_perf_sw_event(enum perf_type_id type, u32 event_id,
- u64 nr, int nmi,
- struct perf_sample_data *data,
- struct pt_regs *regs)
-{
- struct perf_cpu_context *cpuctx;
- struct perf_event *event;
- struct hlist_node *node;
- struct hlist_head *head;
-
- cpuctx = &__get_cpu_var(perf_cpu_context);
-
- rcu_read_lock();
-
- head = find_swevent_head_rcu(cpuctx, type, event_id);
-
- if (!head)
- goto end;
-
- hlist_for_each_entry_rcu(event, node, head, hlist_entry) {
- if (perf_swevent_match(event, type, event_id, data, regs))
- perf_swevent_add(event, nr, nmi, data, regs);
- }
-end:
- rcu_read_unlock();
-}
-
-int perf_swevent_get_recursion_context(void)
-{
- struct perf_cpu_context *cpuctx = &__get_cpu_var(perf_cpu_context);
- int rctx;
-
- if (in_nmi())
- rctx = 3;
- else if (in_irq())
- rctx = 2;
- else if (in_softirq())
- rctx = 1;
- else
- rctx = 0;
-
- if (cpuctx->recursion[rctx])
- return -1;
-
- cpuctx->recursion[rctx]++;
- barrier();
-
- return rctx;
-}
-EXPORT_SYMBOL_GPL(perf_swevent_get_recursion_context);
-
-void inline perf_swevent_put_recursion_context(int rctx)
-{
- struct perf_cpu_context *cpuctx = &__get_cpu_var(perf_cpu_context);
- barrier();
- cpuctx->recursion[rctx]--;
-}
-
-void __perf_sw_event(u32 event_id, u64 nr, int nmi,
- struct pt_regs *regs, u64 addr)
-{
- struct perf_sample_data data;
- int rctx;
-
- preempt_disable_notrace();
- rctx = perf_swevent_get_recursion_context();
- if (rctx < 0)
- return;
-
- perf_sample_data_init(&data, addr);
-
- do_perf_sw_event(PERF_TYPE_SOFTWARE, event_id, nr, nmi, &data, regs);
-
- perf_swevent_put_recursion_context(rctx);
- preempt_enable_notrace();
-}
-
-static void perf_swevent_read(struct perf_event *event)
-{
-}
-
-static int perf_swevent_enable(struct perf_event *event)
-{
- struct hw_perf_event *hwc = &event->hw;
- struct perf_cpu_context *cpuctx;
- struct hlist_head *head;
-
- cpuctx = &__get_cpu_var(perf_cpu_context);
-
- if (hwc->sample_period) {
- hwc->last_period = hwc->sample_period;
- perf_swevent_set_period(event);
- }
-
- head = find_swevent_head(cpuctx, event);
- if (WARN_ON_ONCE(!head))
- return -EINVAL;
-
- hlist_add_head_rcu(&event->hlist_entry, head);
-
- return 0;
-}
-
-static void perf_swevent_disable(struct perf_event *event)
-{
- hlist_del_rcu(&event->hlist_entry);
-}
-
-static void perf_swevent_void(struct perf_event *event)
-{
-}
-
-static int perf_swevent_int(struct perf_event *event)
-{
- return 0;
-}
-
-static const struct pmu perf_ops_generic = {
- .enable = perf_swevent_enable,
- .disable = perf_swevent_disable,
- .start = perf_swevent_int,
- .stop = perf_swevent_void,
- .read = perf_swevent_read,
- .unthrottle = perf_swevent_void, /* hwc->interrupts already reset */
-};
-
-/*
- * hrtimer based swevent callback
- */
-
-static enum hrtimer_restart perf_swevent_hrtimer(struct hrtimer *hrtimer)
-{
- enum hrtimer_restart ret = HRTIMER_RESTART;
- struct perf_sample_data data;
- struct pt_regs *regs;
- struct perf_event *event;
- u64 period;
-
- event = container_of(hrtimer, struct perf_event, hw.hrtimer);
- event->pmu->read(event);
-
- perf_sample_data_init(&data, 0);
- data.period = event->hw.last_period;
- regs = get_irq_regs();
-
- if (regs && !perf_exclude_event(event, regs)) {
- if (!(event->attr.exclude_idle && current->pid == 0))
- if (perf_event_overflow(event, 0, &data, regs))
- ret = HRTIMER_NORESTART;
- }
-
- period = max_t(u64, 10000, event->hw.sample_period);
- hrtimer_forward_now(hrtimer, ns_to_ktime(period));
-
- return ret;
-}
-
-static void perf_swevent_start_hrtimer(struct perf_event *event)
-{
- struct hw_perf_event *hwc = &event->hw;
-
- hrtimer_init(&hwc->hrtimer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
- hwc->hrtimer.function = perf_swevent_hrtimer;
- if (hwc->sample_period) {
- u64 period;
-
- if (hwc->remaining) {
- if (hwc->remaining < 0)
- period = 10000;
- else
- period = hwc->remaining;
- hwc->remaining = 0;
- } else {
- period = max_t(u64, 10000, hwc->sample_period);
- }
- __hrtimer_start_range_ns(&hwc->hrtimer,
- ns_to_ktime(period), 0,
- HRTIMER_MODE_REL, 0);
- }
-}
-
-static void perf_swevent_cancel_hrtimer(struct perf_event *event)
-{
- struct hw_perf_event *hwc = &event->hw;
-
- if (hwc->sample_period) {
- ktime_t remaining = hrtimer_get_remaining(&hwc->hrtimer);
- hwc->remaining = ktime_to_ns(remaining);
-
- hrtimer_cancel(&hwc->hrtimer);
- }
-}
-
-/*
- * Software event: cpu wall time clock
- */
-
-static void cpu_clock_perf_event_update(struct perf_event *event)
-{
- int cpu = raw_smp_processor_id();
- s64 prev;
- u64 now;
-
- now = cpu_clock(cpu);
- prev = local64_xchg(&event->hw.prev_count, now);
- local64_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();
-
- local64_set(&hwc->prev_count, cpu_clock(cpu));
- perf_swevent_start_hrtimer(event);
-
- return 0;
-}
-
-static void cpu_clock_perf_event_disable(struct perf_event *event)
-{
- perf_swevent_cancel_hrtimer(event);
- cpu_clock_perf_event_update(event);
-}
-
-static void cpu_clock_perf_event_read(struct perf_event *event)
-{
- cpu_clock_perf_event_update(event);
-}
-
-static const struct pmu perf_ops_cpu_clock = {
- .enable = cpu_clock_perf_event_enable,
- .disable = cpu_clock_perf_event_disable,
- .read = cpu_clock_perf_event_read,
-};
-
-/*
- * Software event: task time clock
- */
-
-static void task_clock_perf_event_update(struct perf_event *event, u64 now)
-{
- u64 prev;
- s64 delta;
-
- prev = local64_xchg(&event->hw.prev_count, now);
- delta = now - prev;
- local64_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;
-
- local64_set(&hwc->prev_count, now);
-
- perf_swevent_start_hrtimer(event);
-
- return 0;
-}
-
-static void task_clock_perf_event_disable(struct perf_event *event)
-{
- perf_swevent_cancel_hrtimer(event);
- task_clock_perf_event_update(event, event->ctx->time);
-
-}
-
-static void task_clock_perf_event_read(struct perf_event *event)
-{
- u64 time;
-
- if (!in_nmi()) {
- update_context_time(event->ctx);
- time = event->ctx->time;
- } else {
- u64 now = perf_clock();
- u64 delta = now - event->ctx->timestamp;
- time = event->ctx->time + delta;
- }
-
- task_clock_perf_event_update(event, time);
-}
-
-static const struct pmu perf_ops_task_clock = {
- .enable = task_clock_perf_event_enable,
- .disable = task_clock_perf_event_disable,
- .read = task_clock_perf_event_read,
-};
-
-/* Deref the hlist from the update side */
-static inline struct swevent_hlist *
-swevent_hlist_deref(struct perf_cpu_context *cpuctx)
-{
- return rcu_dereference_protected(cpuctx->swevent_hlist,
- lockdep_is_held(&cpuctx->hlist_mutex));
-}
-
-static void swevent_hlist_release_rcu(struct rcu_head *rcu_head)
-{
- struct swevent_hlist *hlist;
-
- hlist = container_of(rcu_head, struct swevent_hlist, rcu_head);
- kfree(hlist);
-}
-
-static void swevent_hlist_release(struct perf_cpu_context *cpuctx)
-{
- struct swevent_hlist *hlist = swevent_hlist_deref(cpuctx);
-
- if (!hlist)
- return;
-
- rcu_assign_pointer(cpuctx->swevent_hlist, NULL);
- call_rcu(&hlist->rcu_head, swevent_hlist_release_rcu);
-}
-
-static void swevent_hlist_put_cpu(struct perf_event *event, int cpu)
-{
- struct perf_cpu_context *cpuctx = &per_cpu(perf_cpu_context, cpu);
-
- mutex_lock(&cpuctx->hlist_mutex);
-
- if (!--cpuctx->hlist_refcount)
- swevent_hlist_release(cpuctx);
-
- mutex_unlock(&cpuctx->hlist_mutex);
-}
-
-static void swevent_hlist_put(struct perf_event *event)
-{
- int cpu;
-
- if (event->cpu != -1) {
- swevent_hlist_put_cpu(event, event->cpu);
- return;
- }
-
- for_each_possible_cpu(cpu)
- swevent_hlist_put_cpu(event, cpu);
-}
-
-static int swevent_hlist_get_cpu(struct perf_event *event, int cpu)
-{
- struct perf_cpu_context *cpuctx = &per_cpu(perf_cpu_context, cpu);
- int err = 0;
-
- mutex_lock(&cpuctx->hlist_mutex);
-
- if (!swevent_hlist_deref(cpuctx) && cpu_online(cpu)) {
- struct swevent_hlist *hlist;
-
- hlist = kzalloc(sizeof(*hlist), GFP_KERNEL);
- if (!hlist) {
- err = -ENOMEM;
- goto exit;
- }
- rcu_assign_pointer(cpuctx->swevent_hlist, hlist);
- }
- cpuctx->hlist_refcount++;
- exit:
- mutex_unlock(&cpuctx->hlist_mutex);
-
- return err;
-}
-
-static int swevent_hlist_get(struct perf_event *event)
-{
- int err;
- int cpu, failed_cpu;
-
- if (event->cpu != -1)
- return swevent_hlist_get_cpu(event, event->cpu);
-
- get_online_cpus();
- for_each_possible_cpu(cpu) {
- err = swevent_hlist_get_cpu(event, cpu);
- if (err) {
- failed_cpu = cpu;
- goto fail;
- }
- }
- put_online_cpus();
-
- return 0;
- fail:
- for_each_possible_cpu(cpu) {
- if (cpu == failed_cpu)
- break;
- swevent_hlist_put_cpu(event, cpu);
- }
-
- put_online_cpus();
- return err;
-}
-
-#ifdef CONFIG_EVENT_TRACING
-
-static const struct pmu perf_ops_tracepoint = {
- .enable = perf_trace_enable,
- .disable = perf_trace_disable,
- .start = perf_swevent_int,
- .stop = perf_swevent_void,
- .read = perf_swevent_read,
- .unthrottle = perf_swevent_void,
-};
-
-static int perf_tp_filter_match(struct perf_event *event,
- struct perf_sample_data *data)
-{
- void *record = data->raw->data;
-
- if (likely(!event->filter) || filter_match_preds(event->filter, record))
- return 1;
- return 0;
-}
-
-static int perf_tp_event_match(struct perf_event *event,
- struct perf_sample_data *data,
- struct pt_regs *regs)
-{
- /*
- * All tracepoints are from kernel-space.
- */
- if (event->attr.exclude_kernel)
- return 0;
-
- if (!perf_tp_filter_match(event, data))
- return 0;
-
- return 1;
-}
-
-void perf_tp_event(u64 addr, u64 count, void *record, int entry_size,
- struct pt_regs *regs, struct hlist_head *head, int rctx)
-{
- struct perf_sample_data data;
- struct perf_event *event;
- struct hlist_node *node;
-
- struct perf_raw_record raw = {
- .size = entry_size,
- .data = record,
- };
-
- perf_sample_data_init(&data, addr);
- data.raw = &raw;
-
- hlist_for_each_entry_rcu(event, node, head, hlist_entry) {
- if (perf_tp_event_match(event, &data, regs))
- perf_swevent_add(event, count, 1, &data, regs);
- }
-
- perf_swevent_put_recursion_context(rctx);
-}
-EXPORT_SYMBOL_GPL(perf_tp_event);
-
-static void tp_perf_event_destroy(struct perf_event *event)
-{
- perf_trace_destroy(event);
-}
-
-static const struct pmu *tp_perf_event_init(struct perf_event *event)
-{
- int err;
-
- /*
- * Raw tracepoint data is a severe data leak, only allow root to
- * have these.
- */
- if ((event->attr.sample_type & PERF_SAMPLE_RAW) &&
- perf_paranoid_tracepoint_raw() &&
- !capable(CAP_SYS_ADMIN))
- return ERR_PTR(-EPERM);
-
- err = perf_trace_init(event);
- if (err)
- return NULL;
-
- event->destroy = tp_perf_event_destroy;
-
- return &perf_ops_tracepoint;
-}
-
-static int perf_event_set_filter(struct perf_event *event, void __user *arg)
-{
- char *filter_str;
- int ret;
-
- if (event->attr.type != PERF_TYPE_TRACEPOINT)
- return -EINVAL;
-
- filter_str = strndup_user(arg, PAGE_SIZE);
- if (IS_ERR(filter_str))
- return PTR_ERR(filter_str);
-
- ret = ftrace_profile_set_filter(event, event->attr.config, filter_str);
-
- kfree(filter_str);
- return ret;
-}
-
-static void perf_event_free_filter(struct perf_event *event)
-{
- ftrace_profile_free_filter(event);
-}
-
-#else
-
-static const struct pmu *tp_perf_event_init(struct perf_event *event)
-{
- return NULL;
-}
-
-static int perf_event_set_filter(struct perf_event *event, void __user *arg)
-{
- return -ENOENT;
-}
-
-static void perf_event_free_filter(struct perf_event *event)
-{
-}
-
-#endif /* CONFIG_EVENT_TRACING */
-
-#ifdef CONFIG_HAVE_HW_BREAKPOINT
-static void bp_perf_event_destroy(struct perf_event *event)
-{
- release_bp_slot(event);
-}
-
-static const struct pmu *bp_perf_event_init(struct perf_event *bp)
-{
- int err;
-
- err = register_perf_hw_breakpoint(bp);
- if (err)
- return ERR_PTR(err);
-
- bp->destroy = bp_perf_event_destroy;
-
- return &perf_ops_bp;
-}
-
-void perf_bp_event(struct perf_event *bp, void *data)
-{
- struct perf_sample_data sample;
- struct pt_regs *regs = data;
-
- perf_sample_data_init(&sample, bp->attr.bp_addr);
-
- if (!perf_exclude_event(bp, regs))
- perf_swevent_add(bp, 1, 1, &sample, regs);
-}
-#else
-static const struct pmu *bp_perf_event_init(struct perf_event *bp)
-{
- return NULL;
-}
-
-void perf_bp_event(struct perf_event *bp, void *regs)
-{
-}
-#endif
-
-atomic_t perf_swevent_enabled[PERF_COUNT_SW_MAX];
-
-static void sw_perf_event_destroy(struct perf_event *event)
-{
- u64 event_id = event->attr.config;
-
- WARN_ON(event->parent);
-
- atomic_dec(&perf_swevent_enabled[event_id]);
- swevent_hlist_put(event);
-}
-
-static const struct pmu *sw_perf_event_init(struct perf_event *event)
-{
- const struct pmu *pmu = NULL;
- u64 event_id = event->attr.config;
-
- /*
- * Software events (currently) can't in general distinguish
- * between user, kernel and hypervisor events.
- * However, context switches and cpu migrations are considered
- * to be kernel events, and page faults are never hypervisor
- * events.
- */
- switch (event_id) {
- case PERF_COUNT_SW_CPU_CLOCK:
- pmu = &perf_ops_cpu_clock;
-
- break;
- case PERF_COUNT_SW_TASK_CLOCK:
- /*
- * If the user instantiates this as a per-cpu event,
- * use the cpu_clock event instead.
- */
- if (event->ctx->task)
- pmu = &perf_ops_task_clock;
- else
- pmu = &perf_ops_cpu_clock;
-
- break;
- case PERF_COUNT_SW_PAGE_FAULTS:
- case PERF_COUNT_SW_PAGE_FAULTS_MIN:
- case PERF_COUNT_SW_PAGE_FAULTS_MAJ:
- case PERF_COUNT_SW_CONTEXT_SWITCHES:
- case PERF_COUNT_SW_CPU_MIGRATIONS:
- case PERF_COUNT_SW_ALIGNMENT_FAULTS:
- case PERF_COUNT_SW_EMULATION_FAULTS:
- if (!event->parent) {
- int err;
-
- err = swevent_hlist_get(event);
- if (err)
- return ERR_PTR(err);
-
- atomic_inc(&perf_swevent_enabled[event_id]);
- event->destroy = sw_perf_event_destroy;
- }
- pmu = &perf_ops_generic;
- break;
- }
-
- return pmu;
-}
-
-/*
- * Allocate and initialize a event structure
- */
-static struct perf_event *
-perf_event_alloc(struct perf_event_attr *attr,
- int cpu,
- struct perf_event_context *ctx,
- struct perf_event *group_leader,
- struct perf_event *parent_event,
- perf_overflow_handler_t overflow_handler,
- gfp_t gfpflags)
-{
- const struct pmu *pmu;
- struct perf_event *event;
- struct hw_perf_event *hwc;
- long err;
-
- event = kzalloc(sizeof(*event), gfpflags);
- if (!event)
- return ERR_PTR(-ENOMEM);
-
- /*
- * Single events are their own group leaders, with an
- * empty sibling list:
- */
- if (!group_leader)
- group_leader = event;
-
- mutex_init(&event->child_mutex);
- INIT_LIST_HEAD(&event->child_list);
-
- INIT_LIST_HEAD(&event->group_entry);
- INIT_LIST_HEAD(&event->event_entry);
- INIT_LIST_HEAD(&event->sibling_list);
- init_waitqueue_head(&event->waitq);
-
- mutex_init(&event->mmap_mutex);
-
- event->cpu = cpu;
- event->attr = *attr;
- event->group_leader = group_leader;
- event->pmu = NULL;
- event->ctx = ctx;
- event->oncpu = -1;
-
- event->parent = parent_event;
-
- event->ns = get_pid_ns(current->nsproxy->pid_ns);
- event->id = atomic64_inc_return(&perf_event_id);
-
- event->state = PERF_EVENT_STATE_INACTIVE;
-
- if (!overflow_handler && parent_event)
- overflow_handler = parent_event->overflow_handler;
-
- event->overflow_handler = overflow_handler;
-
- if (attr->disabled)
- event->state = PERF_EVENT_STATE_OFF;
-
- pmu = NULL;
-
- hwc = &event->hw;
- hwc->sample_period = attr->sample_period;
- if (attr->freq && attr->sample_freq)
- hwc->sample_period = 1;
- hwc->last_period = hwc->sample_period;
-
- local64_set(&hwc->period_left, hwc->sample_period);
-
- /*
- * we currently do not support PERF_FORMAT_GROUP on inherited events
- */
- if (attr->inherit && (attr->read_format & PERF_FORMAT_GROUP))
- goto done;
-
- switch (attr->type) {
- case PERF_TYPE_RAW:
- case PERF_TYPE_HARDWARE:
- case PERF_TYPE_HW_CACHE:
- pmu = hw_perf_event_init(event);
- break;
-
- case PERF_TYPE_SOFTWARE:
- pmu = sw_perf_event_init(event);
- break;
-
- case PERF_TYPE_TRACEPOINT:
- pmu = tp_perf_event_init(event);
- break;
-
- case PERF_TYPE_BREAKPOINT:
- pmu = bp_perf_event_init(event);
- break;
-
-
- default:
- break;
- }
-done:
- err = 0;
- if (!pmu)
- err = -EINVAL;
- else if (IS_ERR(pmu))
- err = PTR_ERR(pmu);
-
- if (err) {
- if (event->ns)
- put_pid_ns(event->ns);
- kfree(event);
- return ERR_PTR(err);
- }
-
- event->pmu = pmu;
-
- if (!event->parent) {
- atomic_inc(&nr_events);
- if (event->attr.mmap || event->attr.mmap_data)
- atomic_inc(&nr_mmap_events);
- if (event->attr.comm)
- atomic_inc(&nr_comm_events);
- if (event->attr.task)
- atomic_inc(&nr_task_events);
- }
-
- return event;
-}
-
-static int perf_copy_attr(struct perf_event_attr __user *uattr,
- struct perf_event_attr *attr)
-{
- u32 size;
- int ret;
-
- if (!access_ok(VERIFY_WRITE, uattr, PERF_ATTR_SIZE_VER0))
- return -EFAULT;
-
- /*
- * zero the full structure, so that a short copy will be nice.
- */
- memset(attr, 0, sizeof(*attr));
-
- ret = get_user(size, &uattr->size);
- if (ret)
- return ret;
-
- if (size > PAGE_SIZE) /* silly large */
- goto err_size;
-
- if (!size) /* abi compat */
- size = PERF_ATTR_SIZE_VER0;
-
- if (size < PERF_ATTR_SIZE_VER0)
- goto err_size;
-
- /*
- * If we're handed a bigger struct than we know of,
- * ensure all the unknown bits are 0 - i.e. new
- * user-space does not rely on any kernel feature
- * extensions we dont know about yet.
- */
- if (size > sizeof(*attr)) {
- unsigned char __user *addr;
- unsigned char __user *end;
- unsigned char val;
-
- addr = (void __user *)uattr + sizeof(*attr);
- end = (void __user *)uattr + size;
-
- for (; addr < end; addr++) {
- ret = get_user(val, addr);
- if (ret)
- return ret;
- if (val)
- goto err_size;
- }
- size = sizeof(*attr);
- }
-
- ret = copy_from_user(attr, uattr, size);
- if (ret)
- return -EFAULT;
-
- /*
- * If the type exists, the corresponding creation will verify
- * the attr->config.
- */
- if (attr->type >= PERF_TYPE_MAX)
- return -EINVAL;
-
- if (attr->__reserved_1)
- return -EINVAL;
-
- if (attr->sample_type & ~(PERF_SAMPLE_MAX-1))
- return -EINVAL;
-
- if (attr->read_format & ~(PERF_FORMAT_MAX-1))
- return -EINVAL;
-
-out:
- return ret;
-
-err_size:
- put_user(sizeof(*attr), &uattr->size);
- ret = -E2BIG;
- goto out;
-}
-
-static int
-perf_event_set_output(struct perf_event *event, struct perf_event *output_event)
-{
- struct perf_buffer *buffer = NULL, *old_buffer = NULL;
- int ret = -EINVAL;
-
- if (!output_event)
- goto set;
-
- /* don't allow circular references */
- if (event == output_event)
- goto out;
-
- /*
- * Don't allow cross-cpu buffers
- */
- if (output_event->cpu != event->cpu)
- goto out;
-
- /*
- * If its not a per-cpu buffer, it must be the same task.
- */
- if (output_event->cpu == -1 && output_event->ctx != event->ctx)
- goto out;
-
-set:
- mutex_lock(&event->mmap_mutex);
- /* Can't redirect output if we've got an active mmap() */
- if (atomic_read(&event->mmap_count))
- goto unlock;
-
- if (output_event) {
- /* get the buffer we want to redirect to */
- buffer = perf_buffer_get(output_event);
- if (!buffer)
- goto unlock;
- }
-
- old_buffer = event->buffer;
- rcu_assign_pointer(event->buffer, buffer);
- ret = 0;
-unlock:
- mutex_unlock(&event->mmap_mutex);
-
- if (old_buffer)
- perf_buffer_put(old_buffer);
-out:
- return ret;
-}
-
-/**
- * sys_perf_event_open - open a performance event, associate it to a task/cpu
- *
- * @attr_uptr: event_id type attributes for monitoring/sampling
- * @pid: target pid
- * @cpu: target cpu
- * @group_fd: group leader event fd
- */
-SYSCALL_DEFINE5(perf_event_open,
- struct perf_event_attr __user *, attr_uptr,
- pid_t, pid, int, cpu, int, group_fd, unsigned long, flags)
-{
- struct perf_event *event, *group_leader = NULL, *output_event = NULL;
- struct perf_event_attr attr;
- struct perf_event_context *ctx;
- struct file *event_file = NULL;
- struct file *group_file = NULL;
- int event_fd;
- int fput_needed = 0;
- int err;
-
- /* for future expandability... */
- if (flags & ~(PERF_FLAG_FD_NO_GROUP | PERF_FLAG_FD_OUTPUT))
- return -EINVAL;
-
- err = perf_copy_attr(attr_uptr, &attr);
- if (err)
- return err;
-
- if (!attr.exclude_kernel) {
- if (perf_paranoid_kernel() && !capable(CAP_SYS_ADMIN))
- return -EACCES;
- }
-
- if (attr.freq) {
- if (attr.sample_freq > sysctl_perf_event_sample_rate)
- return -EINVAL;
- }
-
- event_fd = get_unused_fd_flags(O_RDWR);
- if (event_fd < 0)
- return event_fd;
-
- /*
- * Get the target context (task or percpu):
- */
- ctx = find_get_context(pid, cpu);
- if (IS_ERR(ctx)) {
- err = PTR_ERR(ctx);
- goto err_fd;
- }
-
- if (group_fd != -1) {
- group_leader = perf_fget_light(group_fd, &fput_needed);
- if (IS_ERR(group_leader)) {
- err = PTR_ERR(group_leader);
- goto err_put_context;
- }
- group_file = group_leader->filp;
- if (flags & PERF_FLAG_FD_OUTPUT)
- output_event = group_leader;
- if (flags & PERF_FLAG_FD_NO_GROUP)
- group_leader = NULL;
- }
-
- /*
- * Look up the group leader (we will attach this event to it):
- */
- if (group_leader) {
- err = -EINVAL;
-
- /*
- * Do not allow a recursive hierarchy (this new sibling
- * becoming part of another group-sibling):
- */
- if (group_leader->group_leader != group_leader)
- goto err_put_context;
- /*
- * Do not allow to attach to a group in a different
- * task or CPU context:
- */
- if (group_leader->ctx != ctx)
- goto err_put_context;
- /*
- * Only a group leader can be exclusive or pinned
- */
- if (attr.exclusive || attr.pinned)
- goto err_put_context;
- }
-
- event = perf_event_alloc(&attr, cpu, ctx, group_leader,
- NULL, NULL, GFP_KERNEL);
- if (IS_ERR(event)) {
- err = PTR_ERR(event);
- goto err_put_context;
- }
-
- if (output_event) {
- err = perf_event_set_output(event, output_event);
- if (err)
- goto err_free_put_context;
- }
-
- event_file = anon_inode_getfile("[perf_event]", &perf_fops, event, O_RDWR);
- if (IS_ERR(event_file)) {
- err = PTR_ERR(event_file);
- goto err_free_put_context;
- }
-
- event->filp = event_file;
- WARN_ON_ONCE(ctx->parent_ctx);
- mutex_lock(&ctx->mutex);
- perf_install_in_context(ctx, event, cpu);
- ++ctx->generation;
- mutex_unlock(&ctx->mutex);
-
- event->owner = current;
- get_task_struct(current);
- mutex_lock(&current->perf_event_mutex);
- list_add_tail(&event->owner_entry, &current->perf_event_list);
- mutex_unlock(&current->perf_event_mutex);
-
- /*
- * Drop the reference on the group_event after placing the
- * new event on the sibling_list. This ensures destruction
- * of the group leader will find the pointer to itself in
- * perf_group_detach().
- */
- fput_light(group_file, fput_needed);
- fd_install(event_fd, event_file);
- return event_fd;
-
-err_free_put_context:
- free_event(event);
-err_put_context:
- fput_light(group_file, fput_needed);
- put_ctx(ctx);
-err_fd:
- put_unused_fd(event_fd);
- return err;
-}
-
-/**
- * perf_event_create_kernel_counter
- *
- * @attr: attributes of the counter to create
- * @cpu: cpu in which the counter is bound
- * @pid: task to profile
- */
-struct perf_event *
-perf_event_create_kernel_counter(struct perf_event_attr *attr, int cpu,
- pid_t pid,
- perf_overflow_handler_t overflow_handler)
-{
- struct perf_event *event;
- struct perf_event_context *ctx;
- int err;
-
- /*
- * Get the target context (task or percpu):
- */
-
- ctx = find_get_context(pid, cpu);
- if (IS_ERR(ctx)) {
- err = PTR_ERR(ctx);
- goto err_exit;
- }
-
- event = perf_event_alloc(attr, cpu, ctx, NULL,
- NULL, overflow_handler, GFP_KERNEL);
- if (IS_ERR(event)) {
- err = PTR_ERR(event);
- goto err_put_context;
- }
-
- event->filp = NULL;
- WARN_ON_ONCE(ctx->parent_ctx);
- mutex_lock(&ctx->mutex);
- perf_install_in_context(ctx, event, cpu);
- ++ctx->generation;
- mutex_unlock(&ctx->mutex);
-
- event->owner = current;
- get_task_struct(current);
- mutex_lock(&current->perf_event_mutex);
- list_add_tail(&event->owner_entry, &current->perf_event_list);
- mutex_unlock(&current->perf_event_mutex);
-
- return event;
-
- err_put_context:
- put_ctx(ctx);
- err_exit:
- return ERR_PTR(err);
-}
-EXPORT_SYMBOL_GPL(perf_event_create_kernel_counter);
-
-/*
- * inherit a event from parent task to child task:
- */
-static struct perf_event *
-inherit_event(struct perf_event *parent_event,
- struct task_struct *parent,
- struct perf_event_context *parent_ctx,
- struct task_struct *child,
- struct perf_event *group_leader,
- struct perf_event_context *child_ctx)
-{
- struct perf_event *child_event;
-
- /*
- * Instead of creating recursive hierarchies of events,
- * we link inherited events back to the original parent,
- * which has a filp for sure, which we use as the reference
- * count:
- */
- if (parent_event->parent)
- parent_event = parent_event->parent;
-
- child_event = perf_event_alloc(&parent_event->attr,
- parent_event->cpu, child_ctx,
- group_leader, parent_event,
- NULL, GFP_KERNEL);
- if (IS_ERR(child_event))
- return child_event;
- get_ctx(child_ctx);
-
- /*
- * Make the child state follow the state of the parent event,
- * not its attr.disabled bit. We hold the parent's mutex,
- * so we won't race with perf_event_{en, dis}able_family.
- */
- if (parent_event->state >= PERF_EVENT_STATE_INACTIVE)
- child_event->state = PERF_EVENT_STATE_INACTIVE;
- else
- child_event->state = PERF_EVENT_STATE_OFF;
-
- if (parent_event->attr.freq) {
- u64 sample_period = parent_event->hw.sample_period;
- struct hw_perf_event *hwc = &child_event->hw;
-
- hwc->sample_period = sample_period;
- hwc->last_period = sample_period;
-
- local64_set(&hwc->period_left, sample_period);
- }
-
- child_event->overflow_handler = parent_event->overflow_handler;
-
- /*
- * Link it up in the child's context:
- */
- add_event_to_ctx(child_event, child_ctx);
-
- /*
- * Get a reference to the parent filp - we will fput it
- * when the child event exits. This is safe to do because
- * we are in the parent and we know that the filp still
- * exists and has a nonzero count:
- */
- atomic_long_inc(&parent_event->filp->f_count);
-
- /*
- * Link this into the parent event's child list
- */
- WARN_ON_ONCE(parent_event->ctx->parent_ctx);
- mutex_lock(&parent_event->child_mutex);
- list_add_tail(&child_event->child_list, &parent_event->child_list);
- mutex_unlock(&parent_event->child_mutex);
-
- return child_event;
-}
-
-static int inherit_group(struct perf_event *parent_event,
- struct task_struct *parent,
- struct perf_event_context *parent_ctx,
- struct task_struct *child,
- struct perf_event_context *child_ctx)
-{
- struct perf_event *leader;
- struct perf_event *sub;
- struct perf_event *child_ctr;
-
- leader = inherit_event(parent_event, parent, parent_ctx,
- child, NULL, child_ctx);
- if (IS_ERR(leader))
- return PTR_ERR(leader);
- list_for_each_entry(sub, &parent_event->sibling_list, group_entry) {
- child_ctr = inherit_event(sub, parent, parent_ctx,
- child, leader, child_ctx);
- if (IS_ERR(child_ctr))
- return PTR_ERR(child_ctr);
- }
- return 0;
-}
-
-static void sync_child_event(struct perf_event *child_event,
- struct task_struct *child)
-{
- struct perf_event *parent_event = child_event->parent;
- u64 child_val;
-
- if (child_event->attr.inherit_stat)
- perf_event_read_event(child_event, child);
-
- child_val = perf_event_count(child_event);
-
- /*
- * Add back the child's count to the parent's count:
- */
- atomic64_add(child_val, &parent_event->child_count);
- atomic64_add(child_event->total_time_enabled,
- &parent_event->child_total_time_enabled);
- atomic64_add(child_event->total_time_running,
- &parent_event->child_total_time_running);
-
- /*
- * Remove this event from the parent's list
- */
- WARN_ON_ONCE(parent_event->ctx->parent_ctx);
- mutex_lock(&parent_event->child_mutex);
- list_del_init(&child_event->child_list);
- mutex_unlock(&parent_event->child_mutex);
-
- /*
- * Release the parent event, if this was the last
- * reference to it.
- */
- fput(parent_event->filp);
-}
-
-static void
-__perf_event_exit_task(struct perf_event *child_event,
- struct perf_event_context *child_ctx,
- struct task_struct *child)
-{
- struct perf_event *parent_event;
-
- perf_event_remove_from_context(child_event);
-
- parent_event = child_event->parent;
- /*
- * It can happen that parent exits first, and has events
- * that are still around due to the child reference. These
- * events need to be zapped - but otherwise linger.
- */
- if (parent_event) {
- sync_child_event(child_event, child);
- free_event(child_event);
- }
-}
-
-/*
- * When a child task exits, feed back event values to parent events.
- */
-void perf_event_exit_task(struct task_struct *child)
-{
- struct perf_event *child_event, *tmp;
- struct perf_event_context *child_ctx;
- unsigned long flags;
-
- if (likely(!child->perf_event_ctxp)) {
- perf_event_task(child, NULL, 0);
- return;
- }
-
- local_irq_save(flags);
- /*
- * We can't reschedule here because interrupts are disabled,
- * and either child is current or it is a task that can't be
- * scheduled, so we are now safe from rescheduling changing
- * our context.
- */
- child_ctx = child->perf_event_ctxp;
- __perf_event_task_sched_out(child_ctx);
-
- /*
- * Take the context lock here so that if find_get_context is
- * reading child->perf_event_ctxp, we wait until it has
- * incremented the context's refcount before we do put_ctx below.
- */
- raw_spin_lock(&child_ctx->lock);
- child->perf_event_ctxp = NULL;
- /*
- * If this context is a clone; unclone it so it can't get
- * swapped to another process while we're removing all
- * the events from it.
- */
- unclone_ctx(child_ctx);
- update_context_time(child_ctx);
- raw_spin_unlock_irqrestore(&child_ctx->lock, flags);
-
- /*
- * Report the task dead after unscheduling the events so that we
- * won't get any samples after PERF_RECORD_EXIT. We can however still
- * get a few PERF_RECORD_READ events.
- */
- perf_event_task(child, child_ctx, 0);
-
- /*
- * We can recurse on the same lock type through:
- *
- * __perf_event_exit_task()
- * sync_child_event()
- * fput(parent_event->filp)
- * perf_release()
- * mutex_lock(&ctx->mutex)
- *
- * But since its the parent context it won't be the same instance.
- */
- mutex_lock(&child_ctx->mutex);
-
-again:
- list_for_each_entry_safe(child_event, tmp, &child_ctx->pinned_groups,
- group_entry)
- __perf_event_exit_task(child_event, child_ctx, child);
-
- list_for_each_entry_safe(child_event, tmp, &child_ctx->flexible_groups,
- group_entry)
- __perf_event_exit_task(child_event, child_ctx, child);
-
- /*
- * If the last event was a group event, it will have appended all
- * its siblings to the list, but we obtained 'tmp' before that which
- * will still point to the list head terminating the iteration.
- */
- if (!list_empty(&child_ctx->pinned_groups) ||
- !list_empty(&child_ctx->flexible_groups))
- goto again;
-
- mutex_unlock(&child_ctx->mutex);
-
- put_ctx(child_ctx);
-}
-
-static void perf_free_event(struct perf_event *event,
- struct perf_event_context *ctx)
-{
- struct perf_event *parent = event->parent;
-
- if (WARN_ON_ONCE(!parent))
- return;
-
- mutex_lock(&parent->child_mutex);
- list_del_init(&event->child_list);
- mutex_unlock(&parent->child_mutex);
-
- fput(parent->filp);
-
- perf_group_detach(event);
- list_del_event(event, ctx);
- free_event(event);
-}
-
-/*
- * free an unexposed, unused context as created by inheritance by
- * init_task below, used by fork() in case of fail.
- */
-void perf_event_free_task(struct task_struct *task)
-{
- struct perf_event_context *ctx = task->perf_event_ctxp;
- struct perf_event *event, *tmp;
-
- if (!ctx)
- return;
-
- mutex_lock(&ctx->mutex);
-again:
- list_for_each_entry_safe(event, tmp, &ctx->pinned_groups, group_entry)
- perf_free_event(event, ctx);
-
- list_for_each_entry_safe(event, tmp, &ctx->flexible_groups,
- group_entry)
- perf_free_event(event, ctx);
-
- if (!list_empty(&ctx->pinned_groups) ||
- !list_empty(&ctx->flexible_groups))
- goto again;
-
- mutex_unlock(&ctx->mutex);
-
- put_ctx(ctx);
-}
-
-static int
-inherit_task_group(struct perf_event *event, struct task_struct *parent,
- struct perf_event_context *parent_ctx,
- struct task_struct *child,
- int *inherited_all)
-{
- int ret;
- struct perf_event_context *child_ctx = child->perf_event_ctxp;
-
- if (!event->attr.inherit) {
- *inherited_all = 0;
- return 0;
- }
-
- if (!child_ctx) {
- /*
- * This is executed from the parent task context, so
- * inherit events that have been marked for cloning.
- * First allocate and initialize a context for the
- * child.
- */
-
- child_ctx = kzalloc(sizeof(struct perf_event_context),
- GFP_KERNEL);
- if (!child_ctx)
- return -ENOMEM;
-
- __perf_event_init_context(child_ctx, child);
- child->perf_event_ctxp = child_ctx;
- get_task_struct(child);
- }
-
- ret = inherit_group(event, parent, parent_ctx,
- child, child_ctx);
-
- if (ret)
- *inherited_all = 0;
-
- return ret;
-}
-
-
-/*
- * Initialize the perf_event context in task_struct
- */
-int perf_event_init_task(struct task_struct *child)
-{
- struct perf_event_context *child_ctx, *parent_ctx;
- struct perf_event_context *cloned_ctx;
- struct perf_event *event;
- struct task_struct *parent = current;
- int inherited_all = 1;
- int ret = 0;
-
- child->perf_event_ctxp = NULL;
-
- mutex_init(&child->perf_event_mutex);
- INIT_LIST_HEAD(&child->perf_event_list);
-
- if (likely(!parent->perf_event_ctxp))
- return 0;
-
- /*
- * If the parent's context is a clone, pin it so it won't get
- * swapped under us.
- */
- parent_ctx = perf_pin_task_context(parent);
-
- /*
- * No need to check if parent_ctx != NULL here; since we saw
- * it non-NULL earlier, the only reason for it to become NULL
- * is if we exit, and since we're currently in the middle of
- * a fork we can't be exiting at the same time.
- */
-
- /*
- * Lock the parent list. No need to lock the child - not PID
- * hashed yet and not running, so nobody can access it.
- */
- mutex_lock(&parent_ctx->mutex);
-
- /*
- * We dont have to disable NMIs - we are only looking at
- * the list, not manipulating it:
- */
- list_for_each_entry(event, &parent_ctx->pinned_groups, group_entry) {
- ret = inherit_task_group(event, parent, parent_ctx, child,
- &inherited_all);
- if (ret)
- break;
- }
-
- list_for_each_entry(event, &parent_ctx->flexible_groups, group_entry) {
- ret = inherit_task_group(event, parent, parent_ctx, child,
- &inherited_all);
- if (ret)
- break;
- }
-
- child_ctx = child->perf_event_ctxp;
-
- if (child_ctx && inherited_all) {
- /*
- * Mark the child context as a clone of the parent
- * context, or of whatever the parent is a clone of.
- * Note that if the parent is a clone, it could get
- * uncloned at any point, but that doesn't matter
- * because the list of events and the generation
- * count can't have changed since we took the mutex.
- */
- cloned_ctx = rcu_dereference(parent_ctx->parent_ctx);
- if (cloned_ctx) {
- child_ctx->parent_ctx = cloned_ctx;
- child_ctx->parent_gen = parent_ctx->parent_gen;
- } else {
- child_ctx->parent_ctx = parent_ctx;
- child_ctx->parent_gen = parent_ctx->generation;
- }
- get_ctx(child_ctx->parent_ctx);
- }
-
- mutex_unlock(&parent_ctx->mutex);
-
- perf_unpin_context(parent_ctx);
-
- return ret;
-}
-
-static void __init perf_event_init_all_cpus(void)
-{
- int cpu;
- struct perf_cpu_context *cpuctx;
-
- for_each_possible_cpu(cpu) {
- cpuctx = &per_cpu(perf_cpu_context, cpu);
- mutex_init(&cpuctx->hlist_mutex);
- __perf_event_init_context(&cpuctx->ctx, NULL);
- }
-}
-
-static void __cpuinit perf_event_init_cpu(int cpu)
-{
- struct perf_cpu_context *cpuctx;
-
- cpuctx = &per_cpu(perf_cpu_context, cpu);
-
- spin_lock(&perf_resource_lock);
- cpuctx->max_pertask = perf_max_events - perf_reserved_percpu;
- spin_unlock(&perf_resource_lock);
-
- mutex_lock(&cpuctx->hlist_mutex);
- if (cpuctx->hlist_refcount > 0) {
- struct swevent_hlist *hlist;
-
- hlist = kzalloc(sizeof(*hlist), GFP_KERNEL);
- WARN_ON_ONCE(!hlist);
- rcu_assign_pointer(cpuctx->swevent_hlist, hlist);
- }
- mutex_unlock(&cpuctx->hlist_mutex);
-}
-
-#ifdef CONFIG_HOTPLUG_CPU
-static void __perf_event_exit_cpu(void *info)
-{
- struct perf_cpu_context *cpuctx = &__get_cpu_var(perf_cpu_context);
- struct perf_event_context *ctx = &cpuctx->ctx;
- struct perf_event *event, *tmp;
-
- list_for_each_entry_safe(event, tmp, &ctx->pinned_groups, group_entry)
- __perf_event_remove_from_context(event);
- list_for_each_entry_safe(event, tmp, &ctx->flexible_groups, group_entry)
- __perf_event_remove_from_context(event);
-}
-static void perf_event_exit_cpu(int cpu)
-{
- struct perf_cpu_context *cpuctx = &per_cpu(perf_cpu_context, cpu);
- struct perf_event_context *ctx = &cpuctx->ctx;
-
- mutex_lock(&cpuctx->hlist_mutex);
- swevent_hlist_release(cpuctx);
- mutex_unlock(&cpuctx->hlist_mutex);
-
- mutex_lock(&ctx->mutex);
- smp_call_function_single(cpu, __perf_event_exit_cpu, NULL, 1);
- mutex_unlock(&ctx->mutex);
-}
-#else
-static inline void perf_event_exit_cpu(int cpu) { }
-#endif
-
-static int __cpuinit
-perf_cpu_notify(struct notifier_block *self, unsigned long action, void *hcpu)
-{
- unsigned int cpu = (long)hcpu;
-
- switch (action & ~CPU_TASKS_FROZEN) {
-
- case CPU_UP_PREPARE:
- case CPU_DOWN_FAILED:
- perf_event_init_cpu(cpu);
- break;
-
- case CPU_UP_CANCELED:
- case CPU_DOWN_PREPARE:
- perf_event_exit_cpu(cpu);
- break;
-
- default:
- break;
- }
-
- return NOTIFY_OK;
-}
-
-/*
- * This has to have a higher priority than migration_notifier in sched.c.
- */
-static struct notifier_block __cpuinitdata perf_cpu_nb = {
- .notifier_call = perf_cpu_notify,
- .priority = 20,
-};
-
-void __init perf_event_init(void)
-{
- perf_event_init_all_cpus();
- perf_cpu_notify(&perf_cpu_nb, (unsigned long)CPU_UP_PREPARE,
- (void *)(long)smp_processor_id());
- perf_cpu_notify(&perf_cpu_nb, (unsigned long)CPU_ONLINE,
- (void *)(long)smp_processor_id());
- register_cpu_notifier(&perf_cpu_nb);
-}
-
-static ssize_t perf_show_reserve_percpu(struct sysdev_class *class,
- struct sysdev_class_attribute *attr,
- char *buf)
-{
- return sprintf(buf, "%d\n", perf_reserved_percpu);
-}
-
-static ssize_t
-perf_set_reserve_percpu(struct sysdev_class *class,
- struct sysdev_class_attribute *attr,
- const char *buf,
- size_t count)
-{
- struct perf_cpu_context *cpuctx;
- unsigned long val;
- int err, cpu, mpt;
-
- err = strict_strtoul(buf, 10, &val);
- if (err)
- return err;
- if (val > perf_max_events)
- return -EINVAL;
-
- spin_lock(&perf_resource_lock);
- perf_reserved_percpu = val;
- for_each_online_cpu(cpu) {
- cpuctx = &per_cpu(perf_cpu_context, cpu);
- raw_spin_lock_irq(&cpuctx->ctx.lock);
- mpt = min(perf_max_events - cpuctx->ctx.nr_events,
- perf_max_events - perf_reserved_percpu);
- cpuctx->max_pertask = mpt;
- raw_spin_unlock_irq(&cpuctx->ctx.lock);
- }
- spin_unlock(&perf_resource_lock);
-
- return count;
-}
-
-static ssize_t perf_show_overcommit(struct sysdev_class *class,
- struct sysdev_class_attribute *attr,
- char *buf)
-{
- return sprintf(buf, "%d\n", perf_overcommit);
-}
-
-static ssize_t
-perf_set_overcommit(struct sysdev_class *class,
- struct sysdev_class_attribute *attr,
- const char *buf, size_t count)
-{
- unsigned long val;
- int err;
-
- err = strict_strtoul(buf, 10, &val);
- if (err)
- return err;
- if (val > 1)
- return -EINVAL;
-
- spin_lock(&perf_resource_lock);
- perf_overcommit = val;
- spin_unlock(&perf_resource_lock);
-
- return count;
-}
-
-static SYSDEV_CLASS_ATTR(
- reserve_percpu,
- 0644,
- perf_show_reserve_percpu,
- perf_set_reserve_percpu
- );
-
-static SYSDEV_CLASS_ATTR(
- overcommit,
- 0644,
- perf_show_overcommit,
- perf_set_overcommit
- );
-
-static struct attribute *perfclass_attrs[] = {
- &attr_reserve_percpu.attr,
- &attr_overcommit.attr,
- NULL
-};
-
-static struct attribute_group perfclass_attr_group = {
- .attrs = perfclass_attrs,
- .name = "perf_events",
-};
-
-static int __init perf_event_sysfs_init(void)
-{
- return sysfs_create_group(&cpu_sysdev_class.kset.kobj,
- &perfclass_attr_group);
-}
-device_initcall(perf_event_sysfs_init);
--
1.7.3.1