Linux-2.6.33.2/kernel/perf_event.c
/*
* Performance events core code:
*
* Copyright (C) 2008 Thomas Gleixner <tglx@linutronix.de>
* Copyright (C) 2008-2009 Red Hat, Inc., Ingo Molnar
* Copyright (C) 2008-2009 Red Hat, Inc., Peter Zijlstra <pzijlstr@redhat.com>
* Copyright © 2009 Paul Mackerras, IBM Corp. <paulus@au1.ibm.com>
*
* For licensing details see kernel-base/COPYING
*/
#include <linux/fs.h>
#include <linux/mm.h>
#include <linux/cpu.h>
#include <linux/smp.h>
#include <linux/file.h>
#include <linux/poll.h>
#include <linux/sysfs.h>
#include <linux/dcache.h>
#include <linux/percpu.h>
#include <linux/ptrace.h>
#include <linux/vmstat.h>
#include <linux/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;
static inline bool perf_paranoid_tracepoint_raw(void)
{
return sysctl_perf_event_paranoid > -1;
}
static inline bool perf_paranoid_cpu(void)
{
return sysctl_perf_event_paranoid > 0;
}
static inline bool perf_paranoid_kernel(void)
{
return sysctl_perf_event_paranoid > 1;
}
int sysctl_perf_event_mlock __read_mostly = 512; /* 'free' kb per user */
/*
* max perf event sample rate
*/
int sysctl_perf_event_sample_rate __read_mostly = 100000;
static atomic64_t perf_event_id;
/*
* Lock for (sysadmin-configurable) event reservations:
*/
static DEFINE_SPINLOCK(perf_resource_lock);
/*
* Architecture provided APIs - weak aliases:
*/
extern __weak const struct pmu *hw_perf_event_init(struct perf_event *event)
{
return NULL;
}
void __weak hw_perf_disable(void) { barrier(); }
void __weak hw_perf_enable(void) { barrier(); }
void __weak hw_perf_event_setup(int cpu) { barrier(); }
void __weak hw_perf_event_setup_online(int cpu) { barrier(); }
int __weak
hw_perf_group_sched_in(struct perf_event *group_leader,
struct perf_cpu_context *cpuctx,
struct perf_event_context *ctx, int cpu)
{
return 0;
}
void __weak perf_event_print_debug(void) { }
static DEFINE_PER_CPU(int, perf_disable_count);
void __perf_disable(void)
{
__get_cpu_var(perf_disable_count)++;
}
bool __perf_enable(void)
{
return !--__get_cpu_var(perf_disable_count);
}
void perf_disable(void)
{
__perf_disable();
hw_perf_disable();
}
void perf_enable(void)
{
if (__perf_enable())
hw_perf_enable();
}
static void get_ctx(struct perf_event_context *ctx)
{
WARN_ON(!atomic_inc_not_zero(&ctx->refcount));
}
static void free_ctx(struct rcu_head *head)
{
struct perf_event_context *ctx;
ctx = container_of(head, struct perf_event_context, rcu_head);
kfree(ctx);
}
static void put_ctx(struct perf_event_context *ctx)
{
if (atomic_dec_and_test(&ctx->refcount)) {
if (ctx->parent_ctx)
put_ctx(ctx->parent_ctx);
if (ctx->task)
put_task_struct(ctx->task);
call_rcu(&ctx->rcu_head, free_ctx);
}
}
static void unclone_ctx(struct perf_event_context *ctx)
{
if (ctx->parent_ctx) {
put_ctx(ctx->parent_ctx);
ctx->parent_ctx = NULL;
}
}
/*
* If we inherit events we want to return the parent event id
* to userspace.
*/
static u64 primary_event_id(struct perf_event *event)
{
u64 id = event->id;
if (event->parent)
id = event->parent->id;
return id;
}
/*
* Get the perf_event_context for a task and lock it.
* This has to cope with with the fact that until it is locked,
* the context could get moved to another task.
*/
static struct perf_event_context *
perf_lock_task_context(struct task_struct *task, unsigned long *flags)
{
struct perf_event_context *ctx;
rcu_read_lock();
retry:
ctx = rcu_dereference(task->perf_event_ctxp);
if (ctx) {
/*
* If this context is a clone of another, it might
* get swapped for another underneath us by
* perf_event_task_sched_out, though the
* rcu_read_lock() protects us from any context
* getting freed. Lock the context and check if it
* got swapped before we could get the lock, and retry
* if so. If we locked the right context, then it
* can't get swapped on us any more.
*/
raw_spin_lock_irqsave(&ctx->lock, *flags);
if (ctx != rcu_dereference(task->perf_event_ctxp)) {
raw_spin_unlock_irqrestore(&ctx->lock, *flags);
goto retry;
}
if (!atomic_inc_not_zero(&ctx->refcount)) {
raw_spin_unlock_irqrestore(&ctx->lock, *flags);
ctx = NULL;
}
}
rcu_read_unlock();
return ctx;
}
/*
* Get the context for a task and increment its pin_count so it
* can't get swapped to another task. This also increments its
* reference count so that the context can't get freed.
*/
static struct perf_event_context *perf_pin_task_context(struct task_struct *task)
{
struct perf_event_context *ctx;
unsigned long flags;
ctx = perf_lock_task_context(task, &flags);
if (ctx) {
++ctx->pin_count;
raw_spin_unlock_irqrestore(&ctx->lock, flags);
}
return ctx;
}
static void perf_unpin_context(struct perf_event_context *ctx)
{
unsigned long flags;
raw_spin_lock_irqsave(&ctx->lock, flags);
--ctx->pin_count;
raw_spin_unlock_irqrestore(&ctx->lock, flags);
put_ctx(ctx);
}
static inline u64 perf_clock(void)
{
return cpu_clock(raw_smp_processor_id());
}
/*
* Update the record of the current time in a context.
*/
static void update_context_time(struct perf_event_context *ctx)
{
u64 now = perf_clock();
ctx->time += now - ctx->timestamp;
ctx->timestamp = now;
}
/*
* Update the total_time_enabled and total_time_running fields for a event.
*/
static void update_event_times(struct perf_event *event)
{
struct perf_event_context *ctx = event->ctx;
u64 run_end;
if (event->state < PERF_EVENT_STATE_INACTIVE ||
event->group_leader->state < PERF_EVENT_STATE_INACTIVE)
return;
if (ctx->is_active)
run_end = ctx->time;
else
run_end = event->tstamp_stopped;
event->total_time_enabled = run_end - event->tstamp_enabled;
if (event->state == PERF_EVENT_STATE_INACTIVE)
run_end = event->tstamp_stopped;
else
run_end = ctx->time;
event->total_time_running = run_end - event->tstamp_running;
}
/*
* Add a event from the lists for its context.
* Must be called with ctx->mutex and ctx->lock held.
*/
static void
list_add_event(struct perf_event *event, struct perf_event_context *ctx)
{
struct perf_event *group_leader = event->group_leader;
/*
* Depending on whether it is a standalone or sibling event,
* add it straight to the context's event list, or to the group
* leader's sibling list:
*/
if (group_leader == event)
list_add_tail(&event->group_entry, &ctx->group_list);
else {
list_add_tail(&event->group_entry, &group_leader->sibling_list);
group_leader->nr_siblings++;
}
list_add_rcu(&event->event_entry, &ctx->event_list);
ctx->nr_events++;
if (event->attr.inherit_stat)
ctx->nr_stat++;
}
/*
* Remove a event from the lists for its context.
* Must be called with ctx->mutex and ctx->lock held.
*/
static void
list_del_event(struct perf_event *event, struct perf_event_context *ctx)
{
struct perf_event *sibling, *tmp;
if (list_empty(&event->group_entry))
return;
ctx->nr_events--;
if (event->attr.inherit_stat)
ctx->nr_stat--;
list_del_init(&event->group_entry);
list_del_rcu(&event->event_entry);
if (event->group_leader != event)
event->group_leader->nr_siblings--;
update_event_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;
/*
* If this was a group event with sibling events then
* upgrade the siblings to singleton events by adding them
* to the context list directly:
*/
list_for_each_entry_safe(sibling, tmp, &event->sibling_list, group_entry) {
list_move_tail(&sibling->group_entry, &ctx->group_list);
sibling->group_leader = sibling;
}
}
static void
event_sched_out(struct perf_event *event,
struct perf_cpu_context *cpuctx,
struct perf_event_context *ctx)
{
if (event->state != PERF_EVENT_STATE_ACTIVE)
return;
event->state = PERF_EVENT_STATE_INACTIVE;
if (event->pending_disable) {
event->pending_disable = 0;
event->state = PERF_EVENT_STATE_OFF;
}
event->tstamp_stopped = ctx->time;
event->pmu->disable(event);
event->oncpu = -1;
if (!is_software_event(event))
cpuctx->active_oncpu--;
ctx->nr_active--;
if (event->attr.exclusive || !cpuctx->active_oncpu)
cpuctx->exclusive = 0;
}
static void
group_sched_out(struct perf_event *group_event,
struct perf_cpu_context *cpuctx,
struct perf_event_context *ctx)
{
struct perf_event *event;
if (group_event->state != PERF_EVENT_STATE_ACTIVE)
return;
event_sched_out(group_event, cpuctx, ctx);
/*
* Schedule out siblings (if any):
*/
list_for_each_entry(event, &group_event->sibling_list, group_entry)
event_sched_out(event, cpuctx, ctx);
if (group_event->attr.exclusive)
cpuctx->exclusive = 0;
}
/*
* Cross CPU call to remove a performance event
*
* We disable the event on the hardware level first. After that we
* remove it from the context list.
*/
static void __perf_event_remove_from_context(void *info)
{
struct perf_cpu_context *cpuctx = &__get_cpu_var(perf_cpu_context);
struct perf_event *event = info;
struct perf_event_context *ctx = event->ctx;
/*
* If this is a task context, we need to check whether it is
* the current task context of this cpu. If not it has been
* scheduled out before the smp call arrived.
*/
if (ctx->task && cpuctx->task_ctx != ctx)
return;
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);
}
/*
* Update total_time_enabled and total_time_running for all events in a group.
*/
static void update_group_times(struct perf_event *leader)
{
struct perf_event *event;
update_event_times(leader);
list_for_each_entry(event, &leader->sibling_list, group_entry)
update_event_times(event);
}
/*
* Cross CPU call to disable a performance event
*/
static void __perf_event_disable(void *info)
{
struct perf_event *event = info;
struct perf_cpu_context *cpuctx = &__get_cpu_var(perf_cpu_context);
struct perf_event_context *ctx = event->ctx;
/*
* If this is a per-task event, need to check whether this
* event's task is the current task on this cpu.
*/
if (ctx->task && cpuctx->task_ctx != ctx)
return;
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,
int cpu)
{
if (event->state <= PERF_EVENT_STATE_OFF)
return 0;
event->state = PERF_EVENT_STATE_ACTIVE;
event->oncpu = cpu; /* TODO: put 'cpu' into cpuctx->cpu */
/*
* The new state must be visible before we turn it on in the hardware:
*/
smp_wmb();
if (event->pmu->enable(event)) {
event->state = PERF_EVENT_STATE_INACTIVE;
event->oncpu = -1;
return -EAGAIN;
}
event->tstamp_running += ctx->time - event->tstamp_stopped;
if (!is_software_event(event))
cpuctx->active_oncpu++;
ctx->nr_active++;
if (event->attr.exclusive)
cpuctx->exclusive = 1;
return 0;
}
static int
group_sched_in(struct perf_event *group_event,
struct perf_cpu_context *cpuctx,
struct perf_event_context *ctx,
int cpu)
{
struct perf_event *event, *partial_group;
int ret;
if (group_event->state == PERF_EVENT_STATE_OFF)
return 0;
ret = hw_perf_group_sched_in(group_event, cpuctx, ctx, cpu);
if (ret)
return ret < 0 ? ret : 0;
if (event_sched_in(group_event, cpuctx, ctx, cpu))
return -EAGAIN;
/*
* Schedule in siblings as one group (if any):
*/
list_for_each_entry(event, &group_event->sibling_list, group_entry) {
if (event_sched_in(event, cpuctx, ctx, cpu)) {
partial_group = event;
goto group_error;
}
}
return 0;
group_error:
/*
* Groups can be scheduled in as one unit only, so undo any
* partial group before returning:
*/
list_for_each_entry(event, &group_event->sibling_list, group_entry) {
if (event == partial_group)
break;
event_sched_out(event, cpuctx, ctx);
}
event_sched_out(group_event, cpuctx, ctx);
return -EAGAIN;
}
/*
* Return 1 for a group consisting entirely of software events,
* 0 if the group contains any hardware events.
*/
static int is_software_only_group(struct perf_event *leader)
{
struct perf_event *event;
if (!is_software_event(leader))
return 0;
list_for_each_entry(event, &leader->sibling_list, group_entry)
if (!is_software_event(event))
return 0;
return 1;
}
/*
* Work out whether we can put this event group on the CPU now.
*/
static int group_can_go_on(struct perf_event *event,
struct perf_cpu_context *cpuctx,
int can_add_hw)
{
/*
* Groups consisting entirely of software events can always go on.
*/
if (is_software_only_group(event))
return 1;
/*
* If an exclusive group is already on, no other hardware
* events can go on.
*/
if (cpuctx->exclusive)
return 0;
/*
* If this group is exclusive and there are already
* events on the CPU, it can't go on.
*/
if (event->attr.exclusive && cpuctx->active_oncpu)
return 0;
/*
* Otherwise, try to add it if all previous groups were able
* to go on.
*/
return can_add_hw;
}
static void add_event_to_ctx(struct perf_event *event,
struct perf_event_context *ctx)
{
list_add_event(event, ctx);
event->tstamp_enabled = ctx->time;
event->tstamp_running = ctx->time;
event->tstamp_stopped = ctx->time;
}
/*
* Cross CPU call to install and enable a performance event
*
* Must be called with ctx->mutex held
*/
static void __perf_install_in_context(void *info)
{
struct perf_cpu_context *cpuctx = &__get_cpu_var(perf_cpu_context);
struct perf_event *event = info;
struct perf_event_context *ctx = event->ctx;
struct perf_event *leader = event->group_leader;
int cpu = smp_processor_id();
int err;
/*
* If this is a task context, we need to check whether it is
* the current task context of this cpu. If not it has been
* scheduled out before the smp call arrived.
* Or possibly this is the right context but it isn't
* on this cpu because it had no events.
*/
if (ctx->task && cpuctx->task_ctx != ctx) {
if (cpuctx->task_ctx || ctx->task != current)
return;
cpuctx->task_ctx = ctx;
}
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, cpu);
if (err) {
/*
* This event couldn't go on. If it is in a group
* then we have to pull the whole group off.
* If the event group is pinned then put it in error state.
*/
if (leader != event)
group_sched_out(leader, cpuctx, ctx);
if (leader->attr.pinned) {
update_group_times(leader);
leader->state = PERF_EVENT_STATE_ERROR;
}
}
if (!err && !ctx->task && cpuctx->max_pertask)
cpuctx->max_pertask--;
unlock:
perf_enable();
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,
smp_processor_id());
else
err = event_sched_in(event, cpuctx, ctx,
smp_processor_id());
perf_enable();
}
if (err) {
/*
* If this event can't go on and it's part of a
* group, then the whole group has to come off.
*/
if (leader != event)
group_sched_out(leader, cpuctx, ctx);
if (leader->attr.pinned) {
update_group_times(leader);
leader->state = PERF_EVENT_STATE_ERROR;
}
}
unlock:
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;
}
void __perf_event_sched_out(struct perf_event_context *ctx,
struct perf_cpu_context *cpuctx)
{
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) {
list_for_each_entry(event, &ctx->group_list, group_entry)
group_sched_out(event, cpuctx, ctx);
}
perf_enable();
out:
raw_spin_unlock(&ctx->lock);
}
/*
* Test whether two contexts are equivalent, i.e. whether they
* have both been cloned from the same version of the same context
* and they both have the same number of enabled events.
* If the number of enabled events is the same, then the set
* of enabled events should be the same, because these are both
* inherited contexts, therefore we can't access individual events
* in them directly with an fd; we can only enable/disable all
* events via prctl, or enable/disable all events in a family
* via ioctl, which will have the same effect on both contexts.
*/
static int context_equiv(struct perf_event_context *ctx1,
struct perf_event_context *ctx2)
{
return ctx1->parent_ctx && ctx1->parent_ctx == ctx2->parent_ctx
&& ctx1->parent_gen == ctx2->parent_gen
&& !ctx1->pin_count && !ctx2->pin_count;
}
static void __perf_event_sync_stat(struct perf_event *event,
struct perf_event *next_event)
{
u64 value;
if (!event->attr.inherit_stat)
return;
/*
* Update the event value, we cannot use perf_event_read()
* because we're in the middle of a context switch and have IRQs
* disabled, which upsets smp_call_function_single(), however
* we know the event must be on the current CPU, therefore we
* don't need to use it.
*/
switch (event->state) {
case PERF_EVENT_STATE_ACTIVE:
event->pmu->read(event);
/* fall-through */
case PERF_EVENT_STATE_INACTIVE:
update_event_times(event);
break;
default:
break;
}
/*
* In order to keep per-task stats reliable we need to flip the event
* values when we flip the contexts.
*/
value = atomic64_read(&next_event->count);
value = atomic64_xchg(&event->count, value);
atomic64_set(&next_event->count, value);
swap(event->total_time_enabled, next_event->total_time_enabled);
swap(event->total_time_running, next_event->total_time_running);
/*
* Since we swizzled the values, update the user visible data too.
*/
perf_event_update_userpage(event);
perf_event_update_userpage(next_event);
}
#define list_next_entry(pos, member) \
list_entry(pos->member.next, typeof(*pos), member)
static void perf_event_sync_stat(struct perf_event_context *ctx,
struct perf_event_context *next_ctx)
{
struct perf_event *event, *next_event;
if (!ctx->nr_stat)
return;
update_context_time(ctx);
event = list_first_entry(&ctx->event_list,
struct perf_event, event_entry);
next_event = list_first_entry(&next_ctx->event_list,
struct perf_event, event_entry);
while (&event->event_entry != &ctx->event_list &&
&next_event->event_entry != &next_ctx->event_list) {
__perf_event_sync_stat(event, next_event);
event = list_next_entry(event, event_entry);
next_event = list_next_entry(next_event, event_entry);
}
}
/*
* Called from scheduler to remove the events of the current task,
* with interrupts disabled.
*
* We stop each event and update the event value in event->count.
*
* This does not protect us against NMI, but disable()
* sets the disabled bit in the control field of event _before_
* accessing the event control register. If a NMI hits, then it will
* not restart the event.
*/
void perf_event_task_sched_out(struct task_struct *task,
struct task_struct *next, int cpu)
{
struct perf_cpu_context *cpuctx = &per_cpu(perf_cpu_context, cpu);
struct perf_event_context *ctx = task->perf_event_ctxp;
struct perf_event_context *next_ctx;
struct perf_event_context *parent;
struct pt_regs *regs;
int do_switch = 1;
regs = task_pt_regs(task);
perf_sw_event(PERF_COUNT_SW_CONTEXT_SWITCHES, 1, 1, regs, 0);
if (likely(!ctx || !cpuctx->task_ctx))
return;
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) {
__perf_event_sched_out(ctx, cpuctx);
cpuctx->task_ctx = NULL;
}
}
/*
* Called with IRQs disabled
*/
static void __perf_event_task_sched_out(struct perf_event_context *ctx)
{
struct perf_cpu_context *cpuctx = &__get_cpu_var(perf_cpu_context);
if (!cpuctx->task_ctx)
return;
if (WARN_ON_ONCE(ctx != cpuctx->task_ctx))
return;
__perf_event_sched_out(ctx, cpuctx);
cpuctx->task_ctx = NULL;
}
/*
* Called with IRQs disabled
*/
static void perf_event_cpu_sched_out(struct perf_cpu_context *cpuctx)
{
__perf_event_sched_out(&cpuctx->ctx, cpuctx);
}
static void
__perf_event_sched_in(struct perf_event_context *ctx,
struct perf_cpu_context *cpuctx, int cpu)
{
struct perf_event *event;
int can_add_hw = 1;
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.
*/
list_for_each_entry(event, &ctx->group_list, group_entry) {
if (event->state <= PERF_EVENT_STATE_OFF ||
!event->attr.pinned)
continue;
if (event->cpu != -1 && event->cpu != cpu)
continue;
if (group_can_go_on(event, cpuctx, 1))
group_sched_in(event, cpuctx, ctx, cpu);
/*
* If this pinned group hasn't been scheduled,
* put it in error state.
*/
if (event->state == PERF_EVENT_STATE_INACTIVE) {
update_group_times(event);
event->state = PERF_EVENT_STATE_ERROR;
}
}
list_for_each_entry(event, &ctx->group_list, group_entry) {
/*
* Ignore events in OFF or ERROR state, and
* ignore pinned events since we did them already.
*/
if (event->state <= PERF_EVENT_STATE_OFF ||
event->attr.pinned)
continue;
/*
* Listen to the 'cpu' scheduling filter constraint
* of events:
*/
if (event->cpu != -1 && event->cpu != cpu)
continue;
if (group_can_go_on(event, cpuctx, can_add_hw))
if (group_sched_in(event, cpuctx, ctx, cpu))
can_add_hw = 0;
}
perf_enable();
out:
raw_spin_unlock(&ctx->lock);
}
/*
* Called from scheduler to add the events of the current task
* with interrupts disabled.
*
* We restore the event value and then enable it.
*
* This does not protect us against NMI, but enable()
* sets the enabled bit in the control field of event _before_
* accessing the event control register. If a NMI hits, then it will
* keep the event running.
*/
void perf_event_task_sched_in(struct task_struct *task, int cpu)
{
struct perf_cpu_context *cpuctx = &per_cpu(perf_cpu_context, cpu);
struct perf_event_context *ctx = task->perf_event_ctxp;
if (likely(!ctx))
return;
if (cpuctx->task_ctx == ctx)
return;
__perf_event_sched_in(ctx, cpuctx, cpu);
cpuctx->task_ctx = ctx;
}
static void perf_event_cpu_sched_in(struct perf_cpu_context *cpuctx, int cpu)
{
struct perf_event_context *ctx = &cpuctx->ctx;
__perf_event_sched_in(ctx, cpuctx, cpu);
}
#define MAX_INTERRUPTS (~0ULL)
static void perf_log_throttle(struct perf_event *event, int enable);
static 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;
}
return div64_u64(dividend, divisor);
}
static void perf_adjust_period(struct perf_event *event, u64 nsec, u64 count)
{
struct hw_perf_event *hwc = &event->hw;
u64 period, sample_period;
s64 delta;
period = perf_calculate_period(event, nsec, count);
delta = (s64)(period - hwc->sample_period);
delta = (delta + 7) / 8; /* low pass filter */
sample_period = hwc->sample_period + delta;
if (!sample_period)
sample_period = 1;
hwc->sample_period = sample_period;
if (atomic64_read(&hwc->period_left) > 8*sample_period) {
perf_disable();
event->pmu->disable(event);
atomic64_set(&hwc->period_left, 0);
event->pmu->enable(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);
event->pmu->unthrottle(event);
}
if (!event->attr.freq || !event->attr.sample_freq)
continue;
event->pmu->read(event);
now = atomic64_read(&event->count);
delta = now - hwc->freq_count_stamp;
hwc->freq_count_stamp = now;
if (delta > 0)
perf_adjust_period(event, TICK_NSEC, delta);
}
raw_spin_unlock(&ctx->lock);
}
/*
* Round-robin a context's events:
*/
static void rotate_ctx(struct perf_event_context *ctx)
{
struct perf_event *event;
if (!ctx->nr_events)
return;
raw_spin_lock(&ctx->lock);
/*
* Rotate the first entry last (works just fine for group events too):
*/
perf_disable();
list_for_each_entry(event, &ctx->group_list, group_entry) {
list_move_tail(&event->group_entry, &ctx->group_list);
break;
}
perf_enable();
raw_spin_unlock(&ctx->lock);
}
void perf_event_task_tick(struct task_struct *curr, int cpu)
{
struct perf_cpu_context *cpuctx;
struct perf_event_context *ctx;
if (!atomic_read(&nr_events))
return;
cpuctx = &per_cpu(perf_cpu_context, cpu);
ctx = curr->perf_event_ctxp;
perf_ctx_adjust_freq(&cpuctx->ctx);
if (ctx)
perf_ctx_adjust_freq(ctx);
perf_event_cpu_sched_out(cpuctx);
if (ctx)
__perf_event_task_sched_out(ctx);
rotate_ctx(&cpuctx->ctx);
if (ctx)
rotate_ctx(ctx);
perf_event_cpu_sched_in(cpuctx, cpu);
if (ctx)
perf_event_task_sched_in(curr, cpu);
}
/*
* Enable all of a task's events that have been marked enable-on-exec.
* This expects task == current.
*/
static void perf_event_enable_on_exec(struct task_struct *task)
{
struct perf_event_context *ctx;
struct perf_event *event;
unsigned long flags;
int enabled = 0;
local_irq_save(flags);
ctx = task->perf_event_ctxp;
if (!ctx || !ctx->nr_events)
goto out;
__perf_event_task_sched_out(ctx);
raw_spin_lock(&ctx->lock);
list_for_each_entry(event, &ctx->group_list, group_entry) {
if (!event->attr.enable_on_exec)
continue;
event->attr.enable_on_exec = 0;
if (event->state >= PERF_EVENT_STATE_INACTIVE)
continue;
__perf_event_mark_enabled(event, ctx);
enabled = 1;
}
/*
* Unclone this context if we enabled any event.
*/
if (enabled)
unclone_ctx(ctx);
raw_spin_unlock(&ctx->lock);
perf_event_task_sched_in(task, smp_processor_id());
out:
local_irq_restore(flags);
}
/*
* Cross CPU call to read the hardware event
*/
static void __perf_event_read(void *info)
{
struct perf_cpu_context *cpuctx = &__get_cpu_var(perf_cpu_context);
struct perf_event *event = info;
struct perf_event_context *ctx = event->ctx;
/*
* If this is a task context, we need to check whether it is
* the current task context of this cpu. If not it has been
* scheduled out before the smp call arrived. In that case
* event->count would have been updated to a recent sample
* when the event was scheduled out.
*/
if (ctx->task && cpuctx->task_ctx != ctx)
return;
raw_spin_lock(&ctx->lock);
update_context_time(ctx);
update_event_times(event);
raw_spin_unlock(&ctx->lock);
event->pmu->read(event);
}
static u64 perf_event_read(struct perf_event *event)
{
/*
* If event is enabled and currently active on a CPU, update the
* value in the event structure:
*/
if (event->state == PERF_EVENT_STATE_ACTIVE) {
smp_call_function_single(event->oncpu,
__perf_event_read, event, 1);
} else if (event->state == PERF_EVENT_STATE_INACTIVE) {
struct perf_event_context *ctx = event->ctx;
unsigned long flags;
raw_spin_lock_irqsave(&ctx->lock, flags);
update_context_time(ctx);
update_event_times(event);
raw_spin_unlock_irqrestore(&ctx->lock, flags);
}
return atomic64_read(&event->count);
}
/*
* Initialize the perf_event context in a task_struct:
*/
static void
__perf_event_init_context(struct perf_event_context *ctx,
struct task_struct *task)
{
raw_spin_lock_init(&ctx->lock);
mutex_init(&ctx->mutex);
INIT_LIST_HEAD(&ctx->group_list);
INIT_LIST_HEAD(&ctx->event_list);
atomic_set(&ctx->refcount, 1);
ctx->task = task;
}
static struct perf_event_context *find_get_context(pid_t pid, int cpu)
{
struct perf_event_context *ctx;
struct perf_cpu_context *cpuctx;
struct task_struct *task;
unsigned long flags;
int err;
if (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 free_event(struct perf_event *event)
{
perf_pending_sync(event);
if (!event->parent) {
atomic_dec(&nr_events);
if (event->attr.mmap)
atomic_dec(&nr_mmap_events);
if (event->attr.comm)
atomic_dec(&nr_comm_events);
if (event->attr.task)
atomic_dec(&nr_task_events);
}
if (event->output) {
fput(event->output->filp);
event->output = NULL;
}
if (event->destroy)
event->destroy(event);
put_ctx(event->ctx);
call_rcu(&event->rcu_head, free_event_rcu);
}
int perf_event_release_kernel(struct perf_event *event)
{
struct perf_event_context *ctx = event->ctx;
WARN_ON_ONCE(ctx->parent_ctx);
mutex_lock(&ctx->mutex);
perf_event_remove_from_context(event);
mutex_unlock(&ctx->mutex);
mutex_lock(&event->owner->perf_event_mutex);
list_del_init(&event->owner_entry);
mutex_unlock(&event->owner->perf_event_mutex);
put_task_struct(event->owner);
free_event(event);
return 0;
}
EXPORT_SYMBOL_GPL(perf_event_release_kernel);
/*
* Called when the last reference to the file is gone.
*/
static int perf_release(struct inode *inode, struct file *file)
{
struct perf_event *event = file->private_data;
file->private_data = NULL;
return perf_event_release_kernel(event);
}
static int perf_event_read_size(struct perf_event *event)
{
int entry = sizeof(u64); /* value */
int size = 0;
int nr = 1;
if (event->attr.read_format & PERF_FORMAT_TOTAL_TIME_ENABLED)
size += sizeof(u64);
if (event->attr.read_format & PERF_FORMAT_TOTAL_TIME_RUNNING)
size += sizeof(u64);
if (event->attr.read_format & PERF_FORMAT_ID)
entry += sizeof(u64);
if (event->attr.read_format & PERF_FORMAT_GROUP) {
nr += event->group_leader->nr_siblings;
size += sizeof(u64);
}
size += entry * nr;
return size;
}
u64 perf_event_read_value(struct perf_event *event, u64 *enabled, u64 *running)
{
struct perf_event *child;
u64 total = 0;
*enabled = 0;
*running = 0;
mutex_lock(&event->child_mutex);
total += perf_event_read(event);
*enabled += event->total_time_enabled +
atomic64_read(&event->child_total_time_enabled);
*running += event->total_time_running +
atomic64_read(&event->child_total_time_running);
list_for_each_entry(child, &event->child_list, child_list) {
total += perf_event_read(child);
*enabled += child->total_time_enabled;
*running += child->total_time_running;
}
mutex_unlock(&event->child_mutex);
return total;
}
EXPORT_SYMBOL_GPL(perf_event_read_value);
static int perf_event_read_group(struct perf_event *event,
u64 read_format, char __user *buf)
{
struct perf_event *leader = event->group_leader, *sub;
int n = 0, size = 0, ret = -EFAULT;
struct perf_event_context *ctx = leader->ctx;
u64 values[5];
u64 count, enabled, running;
mutex_lock(&ctx->mutex);
count = perf_event_read_value(leader, &enabled, &running);
values[n++] = 1 + leader->nr_siblings;
if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED)
values[n++] = enabled;
if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING)
values[n++] = running;
values[n++] = count;
if (read_format & PERF_FORMAT_ID)
values[n++] = primary_event_id(leader);
size = n * sizeof(u64);
if (copy_to_user(buf, values, size))
goto unlock;
ret = size;
list_for_each_entry(sub, &leader->sibling_list, group_entry) {
n = 0;
values[n++] = perf_event_read_value(sub, &enabled, &running);
if (read_format & PERF_FORMAT_ID)
values[n++] = primary_event_id(sub);
size = n * sizeof(u64);
if (copy_to_user(buf + ret, values, size)) {
ret = -EFAULT;
goto unlock;
}
ret += size;
}
unlock:
mutex_unlock(&ctx->mutex);
return ret;
}
static int perf_event_read_one(struct perf_event *event,
u64 read_format, char __user *buf)
{
u64 enabled, running;
u64 values[4];
int n = 0;
values[n++] = perf_event_read_value(event, &enabled, &running);
if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED)
values[n++] = enabled;
if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING)
values[n++] = running;
if (read_format & PERF_FORMAT_ID)
values[n++] = primary_event_id(event);
if (copy_to_user(buf, values, n * sizeof(u64)))
return -EFAULT;
return n * sizeof(u64);
}
/*
* Read the performance event - simple non blocking version for now
*/
static ssize_t
perf_read_hw(struct perf_event *event, char __user *buf, size_t count)
{
u64 read_format = event->attr.read_format;
int ret;
/*
* Return end-of-file for a read on a event that is in
* error state (i.e. because it was pinned but it couldn't be
* scheduled on to the CPU at some point).
*/
if (event->state == PERF_EVENT_STATE_ERROR)
return 0;
if (count < perf_event_read_size(event))
return -ENOSPC;
WARN_ON_ONCE(event->ctx->parent_ctx);
if (read_format & PERF_FORMAT_GROUP)
ret = perf_event_read_group(event, read_format, buf);
else
ret = perf_event_read_one(event, read_format, buf);
return ret;
}
static ssize_t
perf_read(struct file *file, char __user *buf, size_t count, loff_t *ppos)
{
struct perf_event *event = file->private_data;
return perf_read_hw(event, buf, count);
}
static unsigned int perf_poll(struct file *file, poll_table *wait)
{
struct perf_event *event = file->private_data;
struct perf_mmap_data *data;
unsigned int events = POLL_HUP;
rcu_read_lock();
data = rcu_dereference(event->data);
if (data)
events = atomic_xchg(&data->poll, 0);
rcu_read_unlock();
poll_wait(file, &event->waitq, wait);
return events;
}
static void perf_event_reset(struct perf_event *event)
{
(void)perf_event_read(event);
atomic64_set(&event->count, 0);
perf_event_update_userpage(event);
}
/*
* Holding the top-level event's child_mutex means that any
* descendant process that has inherited this event will block
* in sync_child_event if it goes to exit, thus satisfying the
* task existence requirements of perf_event_enable/disable.
*/
static void perf_event_for_each_child(struct perf_event *event,
void (*func)(struct perf_event *))
{
struct perf_event *child;
WARN_ON_ONCE(event->ctx->parent_ctx);
mutex_lock(&event->child_mutex);
func(event);
list_for_each_entry(child, &event->child_list, child_list)
func(child);
mutex_unlock(&event->child_mutex);
}
static void perf_event_for_each(struct perf_event *event,
void (*func)(struct perf_event *))
{
struct perf_event_context *ctx = event->ctx;
struct perf_event *sibling;
WARN_ON_ONCE(ctx->parent_ctx);
mutex_lock(&ctx->mutex);
event = event->group_leader;
perf_event_for_each_child(event, func);
func(event);
list_for_each_entry(sibling, &event->sibling_list, group_entry)
perf_event_for_each_child(event, func);
mutex_unlock(&ctx->mutex);
}
static int perf_event_period(struct perf_event *event, u64 __user *arg)
{
struct perf_event_context *ctx = event->ctx;
unsigned long size;
int ret = 0;
u64 value;
if (!event->attr.sample_period)
return -EINVAL;
size = copy_from_user(&value, arg, sizeof(value));
if (size != sizeof(value))
return -EFAULT;
if (!value)
return -EINVAL;
raw_spin_lock_irq(&ctx->lock);
if (event->attr.freq) {
if (value > sysctl_perf_event_sample_rate) {
ret = -EINVAL;
goto unlock;
}
event->attr.sample_freq = value;
} else {
event->attr.sample_period = value;
event->hw.sample_period = value;
}
unlock:
raw_spin_unlock_irq(&ctx->lock);
return ret;
}
static int perf_event_set_output(struct perf_event *event, int output_fd);
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:
return perf_event_set_output(event, arg);
case PERF_EVENT_IOC_SET_FILTER:
return perf_event_set_filter(event, (void __user *)arg);
default:
return -ENOTTY;
}
if (flags & PERF_IOC_FLAG_GROUP)
perf_event_for_each(event, func);
else
perf_event_for_each_child(event, func);
return 0;
}
int perf_event_task_enable(void)
{
struct perf_event *event;
mutex_lock(¤t->perf_event_mutex);
list_for_each_entry(event, ¤t->perf_event_list, owner_entry)
perf_event_for_each_child(event, perf_event_enable);
mutex_unlock(¤t->perf_event_mutex);
return 0;
}
int perf_event_task_disable(void)
{
struct perf_event *event;
mutex_lock(¤t->perf_event_mutex);
list_for_each_entry(event, ¤t->perf_event_list, owner_entry)
perf_event_for_each_child(event, perf_event_disable);
mutex_unlock(¤t->perf_event_mutex);
return 0;
}
#ifndef PERF_EVENT_INDEX_OFFSET
# define PERF_EVENT_INDEX_OFFSET 0
#endif
static int perf_event_index(struct perf_event *event)
{
if (event->state != PERF_EVENT_STATE_ACTIVE)
return 0;
return event->hw.idx + 1 - PERF_EVENT_INDEX_OFFSET;
}
/*
* Callers need to ensure there can be no nesting of this function, otherwise
* the seqlock logic goes bad. We can not serialize this because the arch
* code calls this from NMI context.
*/
void perf_event_update_userpage(struct perf_event *event)
{
struct perf_event_mmap_page *userpg;
struct perf_mmap_data *data;
rcu_read_lock();
data = rcu_dereference(event->data);
if (!data)
goto unlock;
userpg = data->user_page;
/*
* Disable preemption so as to not let the corresponding user-space
* spin too long if we get preempted.
*/
preempt_disable();
++userpg->lock;
barrier();
userpg->index = perf_event_index(event);
userpg->offset = atomic64_read(&event->count);
if (event->state == PERF_EVENT_STATE_ACTIVE)
userpg->offset -= atomic64_read(&event->hw.prev_count);
userpg->time_enabled = event->total_time_enabled +
atomic64_read(&event->child_total_time_enabled);
userpg->time_running = event->total_time_running +
atomic64_read(&event->child_total_time_running);
barrier();
++userpg->lock;
preempt_enable();
unlock:
rcu_read_unlock();
}
static unsigned long perf_data_size(struct perf_mmap_data *data)
{
return data->nr_pages << (PAGE_SHIFT + data->data_order);
}
#ifndef CONFIG_PERF_USE_VMALLOC
/*
* Back perf_mmap() with regular GFP_KERNEL-0 pages.
*/
static struct page *
perf_mmap_to_page(struct perf_mmap_data *data, unsigned long pgoff)
{
if (pgoff > data->nr_pages)
return NULL;
if (pgoff == 0)
return virt_to_page(data->user_page);
return virt_to_page(data->data_pages[pgoff - 1]);
}
static struct perf_mmap_data *
perf_mmap_data_alloc(struct perf_event *event, int nr_pages)
{
struct perf_mmap_data *data;
unsigned long size;
int i;
WARN_ON(atomic_read(&event->mmap_count));
size = sizeof(struct perf_mmap_data);
size += nr_pages * sizeof(void *);
data = kzalloc(size, GFP_KERNEL);
if (!data)
goto fail;
data->user_page = (void *)get_zeroed_page(GFP_KERNEL);
if (!data->user_page)
goto fail_user_page;
for (i = 0; i < nr_pages; i++) {
data->data_pages[i] = (void *)get_zeroed_page(GFP_KERNEL);
if (!data->data_pages[i])
goto fail_data_pages;
}
data->data_order = 0;
data->nr_pages = nr_pages;
return data;
fail_data_pages:
for (i--; i >= 0; i--)
free_page((unsigned long)data->data_pages[i]);
free_page((unsigned long)data->user_page);
fail_user_page:
kfree(data);
fail:
return NULL;
}
static void perf_mmap_free_page(unsigned long addr)
{
struct page *page = virt_to_page((void *)addr);
page->mapping = NULL;
__free_page(page);
}
static void perf_mmap_data_free(struct perf_mmap_data *data)
{
int i;
perf_mmap_free_page((unsigned long)data->user_page);
for (i = 0; i < data->nr_pages; i++)
perf_mmap_free_page((unsigned long)data->data_pages[i]);
kfree(data);
}
#else
/*
* Back perf_mmap() with vmalloc memory.
*
* Required for architectures that have d-cache aliasing issues.
*/
static struct page *
perf_mmap_to_page(struct perf_mmap_data *data, unsigned long pgoff)
{
if (pgoff > (1UL << data->data_order))
return NULL;
return vmalloc_to_page((void *)data->user_page + pgoff * PAGE_SIZE);
}
static void perf_mmap_unmark_page(void *addr)
{
struct page *page = vmalloc_to_page(addr);
page->mapping = NULL;
}
static void perf_mmap_data_free_work(struct work_struct *work)
{
struct perf_mmap_data *data;
void *base;
int i, nr;
data = container_of(work, struct perf_mmap_data, work);
nr = 1 << data->data_order;
base = data->user_page;
for (i = 0; i < nr + 1; i++)
perf_mmap_unmark_page(base + (i * PAGE_SIZE));
vfree(base);
kfree(data);
}
static void perf_mmap_data_free(struct perf_mmap_data *data)
{
schedule_work(&data->work);
}
static struct perf_mmap_data *
perf_mmap_data_alloc(struct perf_event *event, int nr_pages)
{
struct perf_mmap_data *data;
unsigned long size;
void *all_buf;
WARN_ON(atomic_read(&event->mmap_count));
size = sizeof(struct perf_mmap_data);
size += sizeof(void *);
data = kzalloc(size, GFP_KERNEL);
if (!data)
goto fail;
INIT_WORK(&data->work, perf_mmap_data_free_work);
all_buf = vmalloc_user((nr_pages + 1) * PAGE_SIZE);
if (!all_buf)
goto fail_all_buf;
data->user_page = all_buf;
data->data_pages[0] = all_buf + PAGE_SIZE;
data->data_order = ilog2(nr_pages);
data->nr_pages = 1;
return data;
fail_all_buf:
kfree(data);
fail:
return NULL;
}
#endif
static int perf_mmap_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
{
struct perf_event *event = vma->vm_file->private_data;
struct perf_mmap_data *data;
int ret = VM_FAULT_SIGBUS;
if (vmf->flags & FAULT_FLAG_MKWRITE) {
if (vmf->pgoff == 0)
ret = 0;
return ret;
}
rcu_read_lock();
data = rcu_dereference(event->data);
if (!data)
goto unlock;
if (vmf->pgoff && (vmf->flags & FAULT_FLAG_WRITE))
goto unlock;
vmf->page = perf_mmap_to_page(data, vmf->pgoff);
if (!vmf->page)
goto unlock;
get_page(vmf->page);
vmf->page->mapping = vma->vm_file->f_mapping;
vmf->page->index = vmf->pgoff;
ret = 0;
unlock:
rcu_read_unlock();
return ret;
}
static void
perf_mmap_data_init(struct perf_event *event, struct perf_mmap_data *data)
{
long max_size = perf_data_size(data);
atomic_set(&data->lock, -1);
if (event->attr.watermark) {
data->watermark = min_t(long, max_size,
event->attr.wakeup_watermark);
}
if (!data->watermark)
data->watermark = max_size / 2;
rcu_assign_pointer(event->data, data);
}
static void perf_mmap_data_free_rcu(struct rcu_head *rcu_head)
{
struct perf_mmap_data *data;
data = container_of(rcu_head, struct perf_mmap_data, rcu_head);
perf_mmap_data_free(data);
}
static void perf_mmap_data_release(struct perf_event *event)
{
struct perf_mmap_data *data = event->data;
WARN_ON(atomic_read(&event->mmap_count));
rcu_assign_pointer(event->data, NULL);
call_rcu(&data->rcu_head, perf_mmap_data_free_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;
WARN_ON_ONCE(event->ctx->parent_ctx);
if (atomic_dec_and_mutex_lock(&event->mmap_count, &event->mmap_mutex)) {
unsigned long size = perf_data_size(event->data);
struct user_struct *user = current_user();
atomic_long_sub((size >> PAGE_SHIFT) + 1, &user->locked_vm);
vma->vm_mm->locked_vm -= event->data->nr_locked;
perf_mmap_data_release(event);
mutex_unlock(&event->mmap_mutex);
}
}
static const struct vm_operations_struct perf_mmap_vmops = {
.open = perf_mmap_open,
.close = perf_mmap_close,
.fault = perf_mmap_fault,
.page_mkwrite = perf_mmap_fault,
};
static int perf_mmap(struct file *file, struct vm_area_struct *vma)
{
struct perf_event *event = file->private_data;
unsigned long user_locked, user_lock_limit;
struct user_struct *user = current_user();
unsigned long locked, lock_limit;
struct perf_mmap_data *data;
unsigned long vma_size;
unsigned long nr_pages;
long user_extra, extra;
int ret = 0;
if (!(vma->vm_flags & VM_SHARED))
return -EINVAL;
vma_size = vma->vm_end - vma->vm_start;
nr_pages = (vma_size / PAGE_SIZE) - 1;
/*
* If we have data pages ensure they're a power-of-two number, so we
* can do bitmasks instead of modulo.
*/
if (nr_pages != 0 && !is_power_of_2(nr_pages))
return -EINVAL;
if (vma_size != PAGE_SIZE * (1 + nr_pages))
return -EINVAL;
if (vma->vm_pgoff != 0)
return -EINVAL;
WARN_ON_ONCE(event->ctx->parent_ctx);
mutex_lock(&event->mmap_mutex);
if (event->output) {
ret = -EINVAL;
goto unlock;
}
if (atomic_inc_not_zero(&event->mmap_count)) {
if (nr_pages != event->data->nr_pages)
ret = -EINVAL;
goto unlock;
}
user_extra = nr_pages + 1;
user_lock_limit = sysctl_perf_event_mlock >> (PAGE_SHIFT - 10);
/*
* Increase the limit linearly with more CPUs:
*/
user_lock_limit *= num_online_cpus();
user_locked = atomic_long_read(&user->locked_vm) + user_extra;
extra = 0;
if (user_locked > user_lock_limit)
extra = user_locked - user_lock_limit;
lock_limit = current->signal->rlim[RLIMIT_MEMLOCK].rlim_cur;
lock_limit >>= PAGE_SHIFT;
locked = vma->vm_mm->locked_vm + extra;
if ((locked > lock_limit) && perf_paranoid_tracepoint_raw() &&
!capable(CAP_IPC_LOCK)) {
ret = -EPERM;
goto unlock;
}
WARN_ON(event->data);
data = perf_mmap_data_alloc(event, nr_pages);
ret = -ENOMEM;
if (!data)
goto unlock;
ret = 0;
perf_mmap_data_init(event, data);
atomic_set(&event->mmap_count, 1);
atomic_long_add(user_extra, &user->locked_vm);
vma->vm_mm->locked_vm += extra;
event->data->nr_locked = extra;
if (vma->vm_flags & VM_WRITE)
event->data->writable = 1;
unlock:
mutex_unlock(&event->mmap_mutex);
vma->vm_flags |= VM_RESERVED;
vma->vm_ops = &perf_mmap_vmops;
return ret;
}
static int perf_fasync(int fd, struct file *filp, int on)
{
struct inode *inode = filp->f_path.dentry->d_inode;
struct perf_event *event = filp->private_data;
int retval;
mutex_lock(&inode->i_mutex);
retval = fasync_helper(fd, filp, on, &event->fasync);
mutex_unlock(&inode->i_mutex);
if (retval < 0)
return retval;
return 0;
}
static const struct file_operations perf_fops = {
.release = perf_release,
.read = perf_read,
.poll = perf_poll,
.unlocked_ioctl = perf_ioctl,
.compat_ioctl = perf_ioctl,
.mmap = perf_mmap,
.fasync = perf_fasync,
};
/*
* Perf event wakeup
*
* If there's data, ensure we set the poll() state and publish everything
* to user-space before waking everybody up.
*/
void perf_event_wakeup(struct perf_event *event)
{
wake_up_all(&event->waitq);
if (event->pending_kill) {
kill_fasync(&event->fasync, SIGIO, event->pending_kill);
event->pending_kill = 0;
}
}
/*
* Pending wakeups
*
* Handle the case where we need to wakeup up from NMI (or rq->lock) context.
*
* The NMI bit means we cannot possibly take locks. Therefore, maintain a
* single linked list and use cmpxchg() to add entries lockless.
*/
static void perf_pending_event(struct perf_pending_entry *entry)
{
struct perf_event *event = container_of(entry,
struct perf_event, pending);
if (event->pending_disable) {
event->pending_disable = 0;
__perf_event_disable(event);
}
if (event->pending_wakeup) {
event->pending_wakeup = 0;
perf_event_wakeup(event);
}
}
#define PENDING_TAIL ((struct perf_pending_entry *)-1UL)
static DEFINE_PER_CPU(struct perf_pending_entry *, perf_pending_head) = {
PENDING_TAIL,
};
static void perf_pending_queue(struct perf_pending_entry *entry,
void (*func)(struct perf_pending_entry *))
{
struct perf_pending_entry **head;
if (cmpxchg(&entry->next, NULL, PENDING_TAIL) != NULL)
return;
entry->func = func;
head = &get_cpu_var(perf_pending_head);
do {
entry->next = *head;
} while (cmpxchg(head, entry->next, entry) != entry->next);
set_perf_event_pending();
put_cpu_var(perf_pending_head);
}
static int __perf_pending_run(void)
{
struct perf_pending_entry *list;
int nr = 0;
list = xchg(&__get_cpu_var(perf_pending_head), PENDING_TAIL);
while (list != PENDING_TAIL) {
void (*func)(struct perf_pending_entry *);
struct perf_pending_entry *entry = list;
list = list->next;
func = entry->func;
entry->next = NULL;
/*
* Ensure we observe the unqueue before we issue the wakeup,
* so that we won't be waiting forever.
* -- see perf_not_pending().
*/
smp_wmb();
func(entry);
nr++;
}
return nr;
}
static inline int perf_not_pending(struct perf_event *event)
{
/*
* If we flush on whatever cpu we run, there is a chance we don't
* need to wait.
*/
get_cpu();
__perf_pending_run();
put_cpu();
/*
* Ensure we see the proper queue state before going to sleep
* so that we do not miss the wakeup. -- see perf_pending_handle()
*/
smp_rmb();
return event->pending.next == NULL;
}
static void perf_pending_sync(struct perf_event *event)
{
wait_event(event->waitq, perf_not_pending(event));
}
void perf_event_do_pending(void)
{
__perf_pending_run();
}
/*
* Callchain support -- arch specific
*/
__weak struct perf_callchain_entry *perf_callchain(struct pt_regs *regs)
{
return NULL;
}
/*
* Output
*/
static bool perf_output_space(struct perf_mmap_data *data, unsigned long tail,
unsigned long offset, unsigned long head)
{
unsigned long mask;
if (!data->writable)
return true;
mask = perf_data_size(data) - 1;
offset = (offset - tail) & mask;
head = (head - tail) & mask;
if ((int)(head - offset) < 0)
return false;
return true;
}
static void perf_output_wakeup(struct perf_output_handle *handle)
{
atomic_set(&handle->data->poll, POLL_IN);
if (handle->nmi) {
handle->event->pending_wakeup = 1;
perf_pending_queue(&handle->event->pending,
perf_pending_event);
} else
perf_event_wakeup(handle->event);
}
/*
* Curious locking construct.
*
* We need to ensure a later event_id doesn't publish a head when a former
* event_id isn't done writing. However since we need to deal with NMIs we
* cannot fully serialize things.
*
* What we do is serialize between CPUs so we only have to deal with NMI
* nesting on a single CPU.
*
* We only publish the head (and generate a wakeup) when the outer-most
* event_id completes.
*/
static void perf_output_lock(struct perf_output_handle *handle)
{
struct perf_mmap_data *data = handle->data;
int cur, cpu = get_cpu();
handle->locked = 0;
for (;;) {
cur = atomic_cmpxchg(&data->lock, -1, cpu);
if (cur == -1) {
handle->locked = 1;
break;
}
if (cur == cpu)
break;
cpu_relax();
}
}
static void perf_output_unlock(struct perf_output_handle *handle)
{
struct perf_mmap_data *data = handle->data;
unsigned long head;
int cpu;
data->done_head = data->head;
if (!handle->locked)
goto out;
again:
/*
* The xchg implies a full barrier that ensures all writes are done
* before we publish the new head, matched by a rmb() in userspace when
* reading this position.
*/
while ((head = atomic_long_xchg(&data->done_head, 0)))
data->user_page->data_head = head;
/*
* NMI can happen here, which means we can miss a done_head update.
*/
cpu = atomic_xchg(&data->lock, -1);
WARN_ON_ONCE(cpu != smp_processor_id());
/*
* Therefore we have to validate we did not indeed do so.
*/
if (unlikely(atomic_long_read(&data->done_head))) {
/*
* Since we had it locked, we can lock it again.
*/
while (atomic_cmpxchg(&data->lock, -1, cpu) != -1)
cpu_relax();
goto again;
}
if (atomic_xchg(&data->wakeup, 0))
perf_output_wakeup(handle);
out:
put_cpu();
}
void perf_output_copy(struct perf_output_handle *handle,
const void *buf, unsigned int len)
{
unsigned int pages_mask;
unsigned long offset;
unsigned int size;
void **pages;
offset = handle->offset;
pages_mask = handle->data->nr_pages - 1;
pages = handle->data->data_pages;
do {
unsigned long page_offset;
unsigned long page_size;
int nr;
nr = (offset >> PAGE_SHIFT) & pages_mask;
page_size = 1UL << (handle->data->data_order + PAGE_SHIFT);
page_offset = offset & (page_size - 1);
size = min_t(unsigned int, page_size - page_offset, len);
memcpy(pages[nr] + page_offset, buf, size);
len -= size;
buf += size;
offset += size;
} while (len);
handle->offset = offset;
/*
* Check we didn't copy past our reservation window, taking the
* possible unsigned int wrap into account.
*/
WARN_ON_ONCE(((long)(handle->head - handle->offset)) < 0);
}
int perf_output_begin(struct perf_output_handle *handle,
struct perf_event *event, unsigned int size,
int nmi, int sample)
{
struct perf_event *output_event;
struct perf_mmap_data *data;
unsigned long tail, offset, head;
int have_lost;
struct {
struct perf_event_header header;
u64 id;
u64 lost;
} lost_event;
rcu_read_lock();
/*
* For inherited events we send all the output towards the parent.
*/
if (event->parent)
event = event->parent;
output_event = rcu_dereference(event->output);
if (output_event)
event = output_event;
data = rcu_dereference(event->data);
if (!data)
goto out;
handle->data = data;
handle->event = event;
handle->nmi = nmi;
handle->sample = sample;
if (!data->nr_pages)
goto fail;
have_lost = atomic_read(&data->lost);
if (have_lost)
size += sizeof(lost_event);
perf_output_lock(handle);
do {
/*
* Userspace could choose to issue a mb() before updating the
* tail pointer. So that all reads will be completed before the
* write is issued.
*/
tail = ACCESS_ONCE(data->user_page->data_tail);
smp_rmb();
offset = head = atomic_long_read(&data->head);
head += size;
if (unlikely(!perf_output_space(data, tail, offset, head)))
goto fail;
} while (atomic_long_cmpxchg(&data->head, offset, head) != offset);
handle->offset = offset;
handle->head = head;
if (head - tail > data->watermark)
atomic_set(&data->wakeup, 1);
if (have_lost) {
lost_event.header.type = PERF_RECORD_LOST;
lost_event.header.misc = 0;
lost_event.header.size = sizeof(lost_event);
lost_event.id = event->id;
lost_event.lost = atomic_xchg(&data->lost, 0);
perf_output_put(handle, lost_event);
}
return 0;
fail:
atomic_inc(&data->lost);
perf_output_unlock(handle);
out:
rcu_read_unlock();
return -ENOSPC;
}
void perf_output_end(struct perf_output_handle *handle)
{
struct perf_event *event = handle->event;
struct perf_mmap_data *data = handle->data;
int wakeup_events = event->attr.wakeup_events;
if (handle->sample && wakeup_events) {
int events = atomic_inc_return(&data->events);
if (events >= wakeup_events) {
atomic_sub(wakeup_events, &data->events);
atomic_set(&data->wakeup, 1);
}
}
perf_output_unlock(handle);
rcu_read_unlock();
}
static u32 perf_event_pid(struct perf_event *event, struct task_struct *p)
{
/*
* only top level events have the pid namespace they were created in
*/
if (event->parent)
event = event->parent;
return task_tgid_nr_ns(p, event->ns);
}
static u32 perf_event_tid(struct perf_event *event, struct task_struct *p)
{
/*
* only top level events have the pid namespace they were created in
*/
if (event->parent)
event = event->parent;
return task_pid_nr_ns(p, event->ns);
}
static void perf_output_read_one(struct perf_output_handle *handle,
struct perf_event *event)
{
u64 read_format = event->attr.read_format;
u64 values[4];
int n = 0;
values[n++] = atomic64_read(&event->count);
if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED) {
values[n++] = event->total_time_enabled +
atomic64_read(&event->child_total_time_enabled);
}
if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING) {
values[n++] = event->total_time_running +
atomic64_read(&event->child_total_time_running);
}
if (read_format & PERF_FORMAT_ID)
values[n++] = primary_event_id(event);
perf_output_copy(handle, values, n * sizeof(u64));
}
/*
* XXX PERF_FORMAT_GROUP vs inherited events seems difficult.
*/
static void perf_output_read_group(struct perf_output_handle *handle,
struct perf_event *event)
{
struct perf_event *leader = event->group_leader, *sub;
u64 read_format = event->attr.read_format;
u64 values[5];
int n = 0;
values[n++] = 1 + leader->nr_siblings;
if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED)
values[n++] = leader->total_time_enabled;
if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING)
values[n++] = leader->total_time_running;
if (leader != event)
leader->pmu->read(leader);
values[n++] = atomic64_read(&leader->count);
if (read_format & PERF_FORMAT_ID)
values[n++] = primary_event_id(leader);
perf_output_copy(handle, values, n * sizeof(u64));
list_for_each_entry(sub, &leader->sibling_list, group_entry) {
n = 0;
if (sub != event)
sub->pmu->read(sub);
values[n++] = atomic64_read(&sub->count);
if (read_format & PERF_FORMAT_ID)
values[n++] = primary_event_id(sub);
perf_output_copy(handle, values, n * sizeof(u64));
}
}
static void perf_output_read(struct perf_output_handle *handle,
struct perf_event *event)
{
if (event->attr.read_format & PERF_FORMAT_GROUP)
perf_output_read_group(handle, event);
else
perf_output_read_one(handle, event);
}
void perf_output_sample(struct perf_output_handle *handle,
struct perf_event_header *header,
struct perf_sample_data *data,
struct perf_event *event)
{
u64 sample_type = data->type;
perf_output_put(handle, *header);
if (sample_type & PERF_SAMPLE_IP)
perf_output_put(handle, data->ip);
if (sample_type & PERF_SAMPLE_TID)
perf_output_put(handle, data->tid_entry);
if (sample_type & PERF_SAMPLE_TIME)
perf_output_put(handle, data->time);
if (sample_type & PERF_SAMPLE_ADDR)
perf_output_put(handle, data->addr);
if (sample_type & PERF_SAMPLE_ID)
perf_output_put(handle, data->id);
if (sample_type & PERF_SAMPLE_STREAM_ID)
perf_output_put(handle, data->stream_id);
if (sample_type & PERF_SAMPLE_CPU)
perf_output_put(handle, data->cpu_entry);
if (sample_type & PERF_SAMPLE_PERIOD)
perf_output_put(handle, data->period);
if (sample_type & PERF_SAMPLE_READ)
perf_output_read(handle, event);
if (sample_type & PERF_SAMPLE_CALLCHAIN) {
if (data->callchain) {
int size = 1;
if (data->callchain)
size += data->callchain->nr;
size *= sizeof(u64);
perf_output_copy(handle, data->callchain, size);
} else {
u64 nr = 0;
perf_output_put(handle, nr);
}
}
if (sample_type & PERF_SAMPLE_RAW) {
if (data->raw) {
perf_output_put(handle, data->raw->size);
perf_output_copy(handle, data->raw->data,
data->raw->size);
} else {
struct {
u32 size;
u32 data;
} raw = {
.size = sizeof(u32),
.data = 0,
};
perf_output_put(handle, raw);
}
}
}
void perf_prepare_sample(struct perf_event_header *header,
struct perf_sample_data *data,
struct perf_event *event,
struct pt_regs *regs)
{
u64 sample_type = event->attr.sample_type;
data->type = sample_type;
header->type = PERF_RECORD_SAMPLE;
header->size = sizeof(*header);
header->misc = 0;
header->misc |= perf_misc_flags(regs);
if (sample_type & PERF_SAMPLE_IP) {
data->ip = perf_instruction_pointer(regs);
header->size += sizeof(data->ip);
}
if (sample_type & PERF_SAMPLE_TID) {
/* namespace issues */
data->tid_entry.pid = perf_event_pid(event, current);
data->tid_entry.tid = perf_event_tid(event, current);
header->size += sizeof(data->tid_entry);
}
if (sample_type & PERF_SAMPLE_TIME) {
data->time = perf_clock();
header->size += sizeof(data->time);
}
if (sample_type & PERF_SAMPLE_ADDR)
header->size += sizeof(data->addr);
if (sample_type & PERF_SAMPLE_ID) {
data->id = primary_event_id(event);
header->size += sizeof(data->id);
}
if (sample_type & PERF_SAMPLE_STREAM_ID) {
data->stream_id = event->id;
header->size += sizeof(data->stream_id);
}
if (sample_type & PERF_SAMPLE_CPU) {
data->cpu_entry.cpu = raw_smp_processor_id();
data->cpu_entry.reserved = 0;
header->size += sizeof(data->cpu_entry);
}
if (sample_type & PERF_SAMPLE_PERIOD)
header->size += sizeof(data->period);
if (sample_type & PERF_SAMPLE_READ)
header->size += perf_event_read_size(event);
if (sample_type & PERF_SAMPLE_CALLCHAIN) {
int size = 1;
data->callchain = perf_callchain(regs);
if (data->callchain)
size += data->callchain->nr;
header->size += size * sizeof(u64);
}
if (sample_type & PERF_SAMPLE_RAW) {
int size = sizeof(u32);
if (data->raw)
size += data->raw->size;
else
size += sizeof(u32);
WARN_ON_ONCE(size & (sizeof(u64)-1));
header->size += size;
}
}
static void perf_event_output(struct perf_event *event, int nmi,
struct perf_sample_data *data,
struct pt_regs *regs)
{
struct perf_output_handle handle;
struct perf_event_header header;
perf_prepare_sample(&header, data, event, regs);
if (perf_output_begin(&handle, event, header.size, nmi, 1))
return;
perf_output_sample(&handle, &header, data, event);
perf_output_end(&handle);
}
/*
* read event_id
*/
struct perf_read_event {
struct perf_event_header header;
u32 pid;
u32 tid;
};
static void
perf_event_read_event(struct perf_event *event,
struct task_struct *task)
{
struct perf_output_handle handle;
struct perf_read_event read_event = {
.header = {
.type = PERF_RECORD_READ,
.misc = 0,
.size = sizeof(read_event) + perf_event_read_size(event),
},
.pid = perf_event_pid(event, task),
.tid = perf_event_tid(event, task),
};
int ret;
ret = perf_output_begin(&handle, event, read_event.header.size, 0, 0);
if (ret)
return;
perf_output_put(&handle, read_event);
perf_output_read(&handle, event);
perf_output_end(&handle);
}
/*
* task tracking -- fork/exit
*
* enabled by: attr.comm | attr.mmap | attr.task
*/
struct perf_task_event {
struct task_struct *task;
struct perf_event_context *task_ctx;
struct {
struct perf_event_header header;
u32 pid;
u32 ppid;
u32 tid;
u32 ptid;
u64 time;
} event_id;
};
static void perf_event_task_output(struct perf_event *event,
struct perf_task_event *task_event)
{
struct perf_output_handle handle;
int size;
struct task_struct *task = task_event->task;
int ret;
size = task_event->event_id.header.size;
ret = perf_output_begin(&handle, event, size, 0, 0);
if (ret)
return;
task_event->event_id.pid = perf_event_pid(event, task);
task_event->event_id.ppid = perf_event_pid(event, current);
task_event->event_id.tid = perf_event_tid(event, task);
task_event->event_id.ptid = perf_event_tid(event, current);
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.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)
{
if (event->state < PERF_EVENT_STATE_INACTIVE)
return 0;
if (event->cpu != -1 && event->cpu != smp_processor_id())
return 0;
if (event->attr.mmap)
return 1;
return 0;
}
static void perf_event_mmap_ctx(struct perf_event_context *ctx,
struct perf_mmap_event *mmap_event)
{
struct perf_event *event;
list_for_each_entry_rcu(event, &ctx->event_list, event_entry) {
if (perf_event_mmap_match(event, mmap_event))
perf_event_mmap_output(event, mmap_event);
}
}
static void perf_event_mmap_event(struct perf_mmap_event *mmap_event)
{
struct perf_cpu_context *cpuctx;
struct perf_event_context *ctx;
struct vm_area_struct *vma = mmap_event->vma;
struct file *file = vma->vm_file;
unsigned int size;
char tmp[16];
char *buf = NULL;
const char *name;
memset(tmp, 0, sizeof(tmp));
if (file) {
/*
* d_path works from the end of the buffer backwards, so we
* need to add enough zero bytes after the string to handle
* the 64bit alignment we do later.
*/
buf = kzalloc(PATH_MAX + sizeof(u64), GFP_KERNEL);
if (!buf) {
name = strncpy(tmp, "//enomem", sizeof(tmp));
goto got_name;
}
name = d_path(&file->f_path, buf, PATH_MAX);
if (IS_ERR(name)) {
name = strncpy(tmp, "//toolong", sizeof(tmp));
goto got_name;
}
} else {
if (arch_vma_name(mmap_event->vma)) {
name = strncpy(tmp, arch_vma_name(mmap_event->vma),
sizeof(tmp));
goto got_name;
}
if (!vma->vm_mm) {
name = strncpy(tmp, "[vdso]", sizeof(tmp));
goto got_name;
}
name = strncpy(tmp, "//anon", sizeof(tmp));
goto got_name;
}
got_name:
size = ALIGN(strlen(name)+1, sizeof(u64));
mmap_event->file_name = name;
mmap_event->file_size = size;
mmap_event->event_id.header.size = sizeof(mmap_event->event_id) + size;
rcu_read_lock();
cpuctx = &get_cpu_var(perf_cpu_context);
perf_event_mmap_ctx(&cpuctx->ctx, mmap_event);
ctx = rcu_dereference(current->perf_event_ctxp);
if (ctx)
perf_event_mmap_ctx(ctx, mmap_event);
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 = 0,
/* .size */
},
/* .pid */
/* .tid */
.start = vma->vm_start,
.len = vma->vm_end - vma->vm_start,
.pgoff = vma->vm_pgoff,
},
};
perf_event_mmap_event(&mmap_event);
}
/*
* IRQ throttle logging
*/
static void perf_log_throttle(struct perf_event *event, int enable)
{
struct perf_output_handle handle;
int ret;
struct {
struct perf_event_header header;
u64 time;
u64 id;
u64 stream_id;
} throttle_event = {
.header = {
.type = PERF_RECORD_THROTTLE,
.misc = 0,
.size = sizeof(throttle_event),
},
.time = perf_clock(),
.id = primary_event_id(event),
.stream_id = event->id,
};
if (enable)
throttle_event.header.type = PERF_RECORD_UNTHROTTLE;
ret = perf_output_begin(&handle, event, sizeof(throttle_event), 1, 0);
if (ret)
return;
perf_output_put(&handle, throttle_event);
perf_output_end(&handle);
}
/*
* Generic event overflow handling, sampling.
*/
static int __perf_event_overflow(struct perf_event *event, int nmi,
int throttle, struct perf_sample_data *data,
struct pt_regs *regs)
{
int events = atomic_read(&event->event_limit);
struct hw_perf_event *hwc = &event->hw;
int ret = 0;
throttle = (throttle && event->pmu->unthrottle != NULL);
if (!throttle) {
hwc->interrupts++;
} else {
if (hwc->interrupts != MAX_INTERRUPTS) {
hwc->interrupts++;
if (HZ * hwc->interrupts >
(u64)sysctl_perf_event_sample_rate) {
hwc->interrupts = MAX_INTERRUPTS;
perf_log_throttle(event, 0);
ret = 1;
}
} else {
/*
* Keep re-disabling events even though on the previous
* pass we disabled it - just in case we raced with a
* sched-in and the event got enabled again:
*/
ret = 1;
}
}
if (event->attr.freq) {
u64 now = perf_clock();
s64 delta = now - hwc->freq_time_stamp;
hwc->freq_time_stamp = now;
if (delta > 0 && delta < 2*TICK_NSEC)
perf_adjust_period(event, delta, hwc->last_period);
}
/*
* XXX event_limit might not quite work as expected on inherited
* events
*/
event->pending_kill = POLL_IN;
if (events && atomic_dec_and_test(&event->event_limit)) {
ret = 1;
event->pending_kill = POLL_HUP;
if (nmi) {
event->pending_disable = 1;
perf_pending_queue(&event->pending,
perf_pending_event);
} else
perf_event_disable(event);
}
if (event->overflow_handler)
event->overflow_handler(event, nmi, data, regs);
else
perf_event_output(event, nmi, data, regs);
return ret;
}
int perf_event_overflow(struct perf_event *event, int nmi,
struct perf_sample_data *data,
struct pt_regs *regs)
{
return __perf_event_overflow(event, nmi, 1, data, regs);
}
/*
* Generic software event infrastructure
*/
/*
* We directly increment event->count and keep a second value in
* event->hw.period_left to count intervals. This period event
* is kept in the range [-sample_period, 0] so that we can use the
* sign as trigger.
*/
static u64 perf_swevent_set_period(struct perf_event *event)
{
struct hw_perf_event *hwc = &event->hw;
u64 period = hwc->last_period;
u64 nr, offset;
s64 old, val;
hwc->last_period = hwc->sample_period;
again:
old = val = atomic64_read(&hwc->period_left);
if (val < 0)
return 0;
nr = div64_u64(period + val, period);
offset = nr * period;
val -= offset;
if (atomic64_cmpxchg(&hwc->period_left, old, val) != old)
goto again;
return nr;
}
static void perf_swevent_overflow(struct perf_event *event, u64 overflow,
int nmi, struct perf_sample_data *data,
struct pt_regs *regs)
{
struct hw_perf_event *hwc = &event->hw;
int throttle = 0;
data->period = event->hw.last_period;
if (!overflow)
overflow = perf_swevent_set_period(event);
if (hwc->interrupts == MAX_INTERRUPTS)
return;
for (; overflow; overflow--) {
if (__perf_event_overflow(event, nmi, throttle,
data, regs)) {
/*
* We inhibit the overflow from happening when
* hwc->interrupts == MAX_INTERRUPTS.
*/
break;
}
throttle = 1;
}
}
static void perf_swevent_unthrottle(struct perf_event *event)
{
/*
* Nothing to do, we already reset hwc->interrupts.
*/
}
static void perf_swevent_add(struct perf_event *event, u64 nr,
int nmi, struct perf_sample_data *data,
struct pt_regs *regs)
{
struct hw_perf_event *hwc = &event->hw;
atomic64_add(nr, &event->count);
if (!regs)
return;
if (!hwc->sample_period)
return;
if (nr == 1 && hwc->sample_period == 1 && !event->attr.freq)
return perf_swevent_overflow(event, 1, nmi, data, regs);
if (atomic64_add_negative(nr, &hwc->period_left))
return;
perf_swevent_overflow(event, 0, nmi, data, regs);
}
static int perf_swevent_is_counting(struct perf_event *event)
{
/*
* The event is active, we're good!
*/
if (event->state == PERF_EVENT_STATE_ACTIVE)
return 1;
/*
* The event is off/error, not counting.
*/
if (event->state != PERF_EVENT_STATE_INACTIVE)
return 0;
/*
* The event is inactive, if the context is active
* we're part of a group that didn't make it on the 'pmu',
* not counting.
*/
if (event->ctx->is_active)
return 0;
/*
* We're inactive and the context is too, this means the
* task is scheduled out, we're counting events that happen
* to us, like migration events.
*/
return 1;
}
static int perf_tp_event_match(struct perf_event *event,
struct perf_sample_data *data);
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->cpu != -1 && event->cpu != smp_processor_id())
return 0;
if (!perf_swevent_is_counting(event))
return 0;
if (event->attr.type != type)
return 0;
if (event->attr.config != event_id)
return 0;
if (perf_exclude_event(event, regs))
return 0;
if (event->attr.type == PERF_TYPE_TRACEPOINT &&
!perf_tp_event_match(event, data))
return 0;
return 1;
}
static void perf_swevent_ctx_event(struct perf_event_context *ctx,
enum perf_type_id type,
u32 event_id, u64 nr, int nmi,
struct perf_sample_data *data,
struct pt_regs *regs)
{
struct perf_event *event;
list_for_each_entry_rcu(event, &ctx->event_list, event_entry) {
if (perf_swevent_match(event, type, event_id, data, regs))
perf_swevent_add(event, nr, nmi, data, regs);
}
}
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]) {
put_cpu_var(perf_cpu_context);
return -1;
}
cpuctx->recursion[rctx]++;
barrier();
return rctx;
}
EXPORT_SYMBOL_GPL(perf_swevent_get_recursion_context);
void perf_swevent_put_recursion_context(int rctx)
{
struct perf_cpu_context *cpuctx = &__get_cpu_var(perf_cpu_context);
barrier();
cpuctx->recursion[rctx]--;
put_cpu_var(perf_cpu_context);
}
EXPORT_SYMBOL_GPL(perf_swevent_put_recursion_context);
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_context *ctx;
cpuctx = &__get_cpu_var(perf_cpu_context);
rcu_read_lock();
perf_swevent_ctx_event(&cpuctx->ctx, type, event_id,
nr, nmi, data, regs);
/*
* doesn't really matter which of the child contexts the
* events ends up in.
*/
ctx = rcu_dereference(current->perf_event_ctxp);
if (ctx)
perf_swevent_ctx_event(ctx, type, event_id, nr, nmi, data, regs);
rcu_read_unlock();
}
void __perf_sw_event(u32 event_id, u64 nr, int nmi,
struct pt_regs *regs, u64 addr)
{
struct perf_sample_data data;
int rctx;
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);
}
static void perf_swevent_read(struct perf_event *event)
{
}
static int perf_swevent_enable(struct perf_event *event)
{
struct hw_perf_event *hwc = &event->hw;
if (hwc->sample_period) {
hwc->last_period = hwc->sample_period;
perf_swevent_set_period(event);
}
return 0;
}
static void perf_swevent_disable(struct perf_event *event)
{
}
static const struct pmu perf_ops_generic = {
.enable = perf_swevent_enable,
.disable = perf_swevent_disable,
.read = perf_swevent_read,
.unthrottle = perf_swevent_unthrottle,
};
/*
* hrtimer based swevent callback
*/
static enum hrtimer_restart perf_swevent_hrtimer(struct hrtimer *hrtimer)
{
enum hrtimer_restart ret = HRTIMER_RESTART;
struct perf_sample_data data;
struct pt_regs *regs;
struct perf_event *event;
u64 period;
event = container_of(hrtimer, struct perf_event, hw.hrtimer);
event->pmu->read(event);
perf_sample_data_init(&data, 0);
data.period = event->hw.last_period;
regs = get_irq_regs();
/*
* In case we exclude kernel IPs or are somehow not in interrupt
* context, provide the next best thing, the user IP.
*/
if ((event->attr.exclude_kernel || !regs) &&
!event->attr.exclude_user)
regs = task_pt_regs(current);
if (regs) {
if (!(event->attr.exclude_idle && current->pid == 0))
if (perf_event_overflow(event, 0, &data, regs))
ret = HRTIMER_NORESTART;
}
period = max_t(u64, 10000, event->hw.sample_period);
hrtimer_forward_now(hrtimer, ns_to_ktime(period));
return ret;
}
static void perf_swevent_start_hrtimer(struct perf_event *event)
{
struct hw_perf_event *hwc = &event->hw;
hrtimer_init(&hwc->hrtimer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
hwc->hrtimer.function = perf_swevent_hrtimer;
if (hwc->sample_period) {
u64 period;
if (hwc->remaining) {
if (hwc->remaining < 0)
period = 10000;
else
period = hwc->remaining;
hwc->remaining = 0;
} else {
period = max_t(u64, 10000, hwc->sample_period);
}
__hrtimer_start_range_ns(&hwc->hrtimer,
ns_to_ktime(period), 0,
HRTIMER_MODE_REL, 0);
}
}
static void perf_swevent_cancel_hrtimer(struct perf_event *event)
{
struct hw_perf_event *hwc = &event->hw;
if (hwc->sample_period) {
ktime_t remaining = hrtimer_get_remaining(&hwc->hrtimer);
hwc->remaining = ktime_to_ns(remaining);
hrtimer_cancel(&hwc->hrtimer);
}
}
/*
* Software event: cpu wall time clock
*/
static void cpu_clock_perf_event_update(struct perf_event *event)
{
int cpu = raw_smp_processor_id();
s64 prev;
u64 now;
now = cpu_clock(cpu);
prev = atomic64_xchg(&event->hw.prev_count, now);
atomic64_add(now - prev, &event->count);
}
static int cpu_clock_perf_event_enable(struct perf_event *event)
{
struct hw_perf_event *hwc = &event->hw;
int cpu = raw_smp_processor_id();
atomic64_set(&hwc->prev_count, cpu_clock(cpu));
perf_swevent_start_hrtimer(event);
return 0;
}
static void cpu_clock_perf_event_disable(struct perf_event *event)
{
perf_swevent_cancel_hrtimer(event);
cpu_clock_perf_event_update(event);
}
static void cpu_clock_perf_event_read(struct perf_event *event)
{
cpu_clock_perf_event_update(event);
}
static const struct pmu perf_ops_cpu_clock = {
.enable = cpu_clock_perf_event_enable,
.disable = cpu_clock_perf_event_disable,
.read = cpu_clock_perf_event_read,
};
/*
* Software event: task time clock
*/
static void task_clock_perf_event_update(struct perf_event *event, u64 now)
{
u64 prev;
s64 delta;
prev = atomic64_xchg(&event->hw.prev_count, now);
delta = now - prev;
atomic64_add(delta, &event->count);
}
static int task_clock_perf_event_enable(struct perf_event *event)
{
struct hw_perf_event *hwc = &event->hw;
u64 now;
now = event->ctx->time;
atomic64_set(&hwc->prev_count, now);
perf_swevent_start_hrtimer(event);
return 0;
}
static void task_clock_perf_event_disable(struct perf_event *event)
{
perf_swevent_cancel_hrtimer(event);
task_clock_perf_event_update(event, event->ctx->time);
}
static void task_clock_perf_event_read(struct perf_event *event)
{
u64 time;
if (!in_nmi()) {
update_context_time(event->ctx);
time = event->ctx->time;
} else {
u64 now = perf_clock();
u64 delta = now - event->ctx->timestamp;
time = event->ctx->time + delta;
}
task_clock_perf_event_update(event, time);
}
static const struct pmu perf_ops_task_clock = {
.enable = task_clock_perf_event_enable,
.disable = task_clock_perf_event_disable,
.read = task_clock_perf_event_read,
};
#ifdef CONFIG_EVENT_PROFILE
void perf_tp_event(int event_id, u64 addr, u64 count, void *record,
int entry_size)
{
struct pt_regs *regs = get_irq_regs();
struct perf_sample_data data;
struct perf_raw_record raw = {
.size = entry_size,
.data = record,
};
perf_sample_data_init(&data, addr);
data.raw = &raw;
if (!regs)
regs = task_pt_regs(current);
/* Trace events already protected against recursion */
do_perf_sw_event(PERF_TYPE_TRACEPOINT, event_id, count, 1,
&data, regs);
}
EXPORT_SYMBOL_GPL(perf_tp_event);
static int perf_tp_event_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 void tp_perf_event_destroy(struct perf_event *event)
{
ftrace_profile_disable(event->attr.config);
}
static const struct pmu *tp_perf_event_init(struct perf_event *event)
{
/*
* Raw tracepoint data is a severe data leak, only allow root to
* have these.
*/
if ((event->attr.sample_type & PERF_SAMPLE_RAW) &&
perf_paranoid_tracepoint_raw() &&
!capable(CAP_SYS_ADMIN))
return ERR_PTR(-EPERM);
if (ftrace_profile_enable(event->attr.config))
return NULL;
event->destroy = tp_perf_event_destroy;
return &perf_ops_generic;
}
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 int perf_tp_event_match(struct perf_event *event,
struct perf_sample_data *data)
{
return 1;
}
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_PROFILE */
#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]);
}
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) {
atomic_inc(&perf_swevent_enabled[event_id]);
event->destroy = sw_perf_event_destroy;
}
pmu = &perf_ops_generic;
break;
}
return pmu;
}
/*
* Allocate and initialize a event structure
*/
static struct perf_event *
perf_event_alloc(struct perf_event_attr *attr,
int cpu,
struct perf_event_context *ctx,
struct perf_event *group_leader,
struct perf_event *parent_event,
perf_overflow_handler_t overflow_handler,
gfp_t gfpflags)
{
const struct pmu *pmu;
struct perf_event *event;
struct hw_perf_event *hwc;
long err;
event = kzalloc(sizeof(*event), gfpflags);
if (!event)
return ERR_PTR(-ENOMEM);
/*
* Single events are their own group leaders, with an
* empty sibling list:
*/
if (!group_leader)
group_leader = event;
mutex_init(&event->child_mutex);
INIT_LIST_HEAD(&event->child_list);
INIT_LIST_HEAD(&event->group_entry);
INIT_LIST_HEAD(&event->event_entry);
INIT_LIST_HEAD(&event->sibling_list);
init_waitqueue_head(&event->waitq);
mutex_init(&event->mmap_mutex);
event->cpu = cpu;
event->attr = *attr;
event->group_leader = group_leader;
event->pmu = NULL;
event->ctx = ctx;
event->oncpu = -1;
event->parent = parent_event;
event->ns = get_pid_ns(current->nsproxy->pid_ns);
event->id = atomic64_inc_return(&perf_event_id);
event->state = PERF_EVENT_STATE_INACTIVE;
if (!overflow_handler && parent_event)
overflow_handler = parent_event->overflow_handler;
event->overflow_handler = overflow_handler;
if (attr->disabled)
event->state = PERF_EVENT_STATE_OFF;
pmu = NULL;
hwc = &event->hw;
hwc->sample_period = attr->sample_period;
if (attr->freq && attr->sample_freq)
hwc->sample_period = 1;
hwc->last_period = hwc->sample_period;
atomic64_set(&hwc->period_left, hwc->sample_period);
/*
* we currently do not support PERF_FORMAT_GROUP on inherited events
*/
if (attr->inherit && (attr->read_format & PERF_FORMAT_GROUP))
goto done;
switch (attr->type) {
case PERF_TYPE_RAW:
case PERF_TYPE_HARDWARE:
case PERF_TYPE_HW_CACHE:
pmu = hw_perf_event_init(event);
break;
case PERF_TYPE_SOFTWARE:
pmu = sw_perf_event_init(event);
break;
case PERF_TYPE_TRACEPOINT:
pmu = tp_perf_event_init(event);
break;
case PERF_TYPE_BREAKPOINT:
pmu = bp_perf_event_init(event);
break;
default:
break;
}
done:
err = 0;
if (!pmu)
err = -EINVAL;
else if (IS_ERR(pmu))
err = PTR_ERR(pmu);
if (err) {
if (event->ns)
put_pid_ns(event->ns);
kfree(event);
return ERR_PTR(err);
}
event->pmu = pmu;
if (!event->parent) {
atomic_inc(&nr_events);
if (event->attr.mmap)
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, int output_fd)
{
struct perf_event *output_event = NULL;
struct file *output_file = NULL;
struct perf_event *old_output;
int fput_needed = 0;
int ret = -EINVAL;
if (!output_fd)
goto set;
output_file = fget_light(output_fd, &fput_needed);
if (!output_file)
return -EBADF;
if (output_file->f_op != &perf_fops)
goto out;
output_event = output_file->private_data;
/* Don't chain output fds */
if (output_event->output)
goto out;
/* Don't set an output fd when we already have an output channel */
if (event->data)
goto out;
atomic_long_inc(&output_file->f_count);
set:
mutex_lock(&event->mmap_mutex);
old_output = event->output;
rcu_assign_pointer(event->output, output_event);
mutex_unlock(&event->mmap_mutex);
if (old_output) {
/*
* we need to make sure no existing perf_output_*()
* is still referencing this event.
*/
synchronize_rcu();
fput(old_output->filp);
}
ret = 0;
out:
fput_light(output_file, fput_needed);
return ret;
}
/**
* sys_perf_event_open - open a performance event, associate it to a task/cpu
*
* @attr_uptr: event_id type attributes for monitoring/sampling
* @pid: target pid
* @cpu: target cpu
* @group_fd: group leader event fd
*/
SYSCALL_DEFINE5(perf_event_open,
struct perf_event_attr __user *, attr_uptr,
pid_t, pid, int, cpu, int, group_fd, unsigned long, flags)
{
struct perf_event *event, *group_leader;
struct perf_event_attr attr;
struct perf_event_context *ctx;
struct file *event_file = NULL;
struct file *group_file = NULL;
int fput_needed = 0;
int fput_needed2 = 0;
int err;
/* for future expandability... */
if (flags & ~(PERF_FLAG_FD_NO_GROUP | PERF_FLAG_FD_OUTPUT))
return -EINVAL;
err = perf_copy_attr(attr_uptr, &attr);
if (err)
return err;
if (!attr.exclude_kernel) {
if (perf_paranoid_kernel() && !capable(CAP_SYS_ADMIN))
return -EACCES;
}
if (attr.freq) {
if (attr.sample_freq > sysctl_perf_event_sample_rate)
return -EINVAL;
}
/*
* Get the target context (task or percpu):
*/
ctx = find_get_context(pid, cpu);
if (IS_ERR(ctx))
return PTR_ERR(ctx);
/*
* Look up the group leader (we will attach this event to it):
*/
group_leader = NULL;
if (group_fd != -1 && !(flags & PERF_FLAG_FD_NO_GROUP)) {
err = -EINVAL;
group_file = fget_light(group_fd, &fput_needed);
if (!group_file)
goto err_put_context;
if (group_file->f_op != &perf_fops)
goto err_put_context;
group_leader = group_file->private_data;
/*
* Do not allow a recursive hierarchy (this new sibling
* becoming part of another group-sibling):
*/
if (group_leader->group_leader != group_leader)
goto err_put_context;
/*
* Do not allow to attach to a group in a different
* task or CPU context:
*/
if (group_leader->ctx != ctx)
goto err_put_context;
/*
* Only a group leader can be exclusive or pinned
*/
if (attr.exclusive || attr.pinned)
goto err_put_context;
}
event = perf_event_alloc(&attr, cpu, ctx, group_leader,
NULL, NULL, GFP_KERNEL);
err = PTR_ERR(event);
if (IS_ERR(event))
goto err_put_context;
err = anon_inode_getfd("[perf_event]", &perf_fops, event, O_RDWR);
if (err < 0)
goto err_free_put_context;
event_file = fget_light(err, &fput_needed2);
if (!event_file)
goto err_free_put_context;
if (flags & PERF_FLAG_FD_OUTPUT) {
err = perf_event_set_output(event, group_fd);
if (err)
goto err_fput_free_put_context;
}
event->filp = event_file;
WARN_ON_ONCE(ctx->parent_ctx);
mutex_lock(&ctx->mutex);
perf_install_in_context(ctx, event, cpu);
++ctx->generation;
mutex_unlock(&ctx->mutex);
event->owner = current;
get_task_struct(current);
mutex_lock(¤t->perf_event_mutex);
list_add_tail(&event->owner_entry, ¤t->perf_event_list);
mutex_unlock(¤t->perf_event_mutex);
err_fput_free_put_context:
fput_light(event_file, fput_needed2);
err_free_put_context:
if (err < 0)
kfree(event);
err_put_context:
if (err < 0)
put_ctx(ctx);
fput_light(group_file, fput_needed);
return err;
}
/**
* perf_event_create_kernel_counter
*
* @attr: attributes of the counter to create
* @cpu: cpu in which the counter is bound
* @pid: task to profile
*/
struct perf_event *
perf_event_create_kernel_counter(struct perf_event_attr *attr, int cpu,
pid_t pid,
perf_overflow_handler_t overflow_handler)
{
struct perf_event *event;
struct perf_event_context *ctx;
int err;
/*
* Get the target context (task or percpu):
*/
ctx = find_get_context(pid, cpu);
if (IS_ERR(ctx)) {
err = PTR_ERR(ctx);
goto err_exit;
}
event = perf_event_alloc(attr, cpu, ctx, NULL,
NULL, overflow_handler, GFP_KERNEL);
if (IS_ERR(event)) {
err = PTR_ERR(event);
goto err_put_context;
}
event->filp = NULL;
WARN_ON_ONCE(ctx->parent_ctx);
mutex_lock(&ctx->mutex);
perf_install_in_context(ctx, event, cpu);
++ctx->generation;
mutex_unlock(&ctx->mutex);
event->owner = current;
get_task_struct(current);
mutex_lock(¤t->perf_event_mutex);
list_add_tail(&event->owner_entry, ¤t->perf_event_list);
mutex_unlock(¤t->perf_event_mutex);
return event;
err_put_context:
put_ctx(ctx);
err_exit:
return ERR_PTR(err);
}
EXPORT_SYMBOL_GPL(perf_event_create_kernel_counter);
/*
* inherit a event from parent task to child task:
*/
static struct perf_event *
inherit_event(struct perf_event *parent_event,
struct task_struct *parent,
struct perf_event_context *parent_ctx,
struct task_struct *child,
struct perf_event *group_leader,
struct perf_event_context *child_ctx)
{
struct perf_event *child_event;
/*
* Instead of creating recursive hierarchies of events,
* we link inherited events back to the original parent,
* which has a filp for sure, which we use as the reference
* count:
*/
if (parent_event->parent)
parent_event = parent_event->parent;
child_event = perf_event_alloc(&parent_event->attr,
parent_event->cpu, child_ctx,
group_leader, parent_event,
NULL, GFP_KERNEL);
if (IS_ERR(child_event))
return child_event;
get_ctx(child_ctx);
/*
* Make the child state follow the state of the parent event,
* not its attr.disabled bit. We hold the parent's mutex,
* so we won't race with perf_event_{en, dis}able_family.
*/
if (parent_event->state >= PERF_EVENT_STATE_INACTIVE)
child_event->state = PERF_EVENT_STATE_INACTIVE;
else
child_event->state = PERF_EVENT_STATE_OFF;
if (parent_event->attr.freq)
child_event->hw.sample_period = parent_event->hw.sample_period;
child_event->overflow_handler = parent_event->overflow_handler;
/*
* Link it up in the child's context:
*/
add_event_to_ctx(child_event, child_ctx);
/*
* Get a reference to the parent filp - we will fput it
* when the child event exits. This is safe to do because
* we are in the parent and we know that the filp still
* exists and has a nonzero count:
*/
atomic_long_inc(&parent_event->filp->f_count);
/*
* Link this into the parent event's child list
*/
WARN_ON_ONCE(parent_event->ctx->parent_ctx);
mutex_lock(&parent_event->child_mutex);
list_add_tail(&child_event->child_list, &parent_event->child_list);
mutex_unlock(&parent_event->child_mutex);
return child_event;
}
static int inherit_group(struct perf_event *parent_event,
struct task_struct *parent,
struct perf_event_context *parent_ctx,
struct task_struct *child,
struct perf_event_context *child_ctx)
{
struct perf_event *leader;
struct perf_event *sub;
struct perf_event *child_ctr;
leader = inherit_event(parent_event, parent, parent_ctx,
child, NULL, child_ctx);
if (IS_ERR(leader))
return PTR_ERR(leader);
list_for_each_entry(sub, &parent_event->sibling_list, group_entry) {
child_ctr = inherit_event(sub, parent, parent_ctx,
child, leader, child_ctx);
if (IS_ERR(child_ctr))
return PTR_ERR(child_ctr);
}
return 0;
}
static void sync_child_event(struct perf_event *child_event,
struct task_struct *child)
{
struct perf_event *parent_event = child_event->parent;
u64 child_val;
if (child_event->attr.inherit_stat)
perf_event_read_event(child_event, child);
child_val = atomic64_read(&child_event->count);
/*
* Add back the child's count to the parent's count:
*/
atomic64_add(child_val, &parent_event->count);
atomic64_add(child_event->total_time_enabled,
&parent_event->child_total_time_enabled);
atomic64_add(child_event->total_time_running,
&parent_event->child_total_time_running);
/*
* Remove this event from the parent's list
*/
WARN_ON_ONCE(parent_event->ctx->parent_ctx);
mutex_lock(&parent_event->child_mutex);
list_del_init(&child_event->child_list);
mutex_unlock(&parent_event->child_mutex);
/*
* Release the parent event, if this was the last
* reference to it.
*/
fput(parent_event->filp);
}
static void
__perf_event_exit_task(struct perf_event *child_event,
struct perf_event_context *child_ctx,
struct task_struct *child)
{
struct perf_event *parent_event;
perf_event_remove_from_context(child_event);
parent_event = child_event->parent;
/*
* It can happen that parent exits first, and has events
* that are still around due to the child reference. These
* events need to be zapped - but otherwise linger.
*/
if (parent_event) {
sync_child_event(child_event, child);
free_event(child_event);
}
}
/*
* When a child task exits, feed back event values to parent events.
*/
void perf_event_exit_task(struct task_struct *child)
{
struct perf_event *child_event, *tmp;
struct perf_event_context *child_ctx;
unsigned long flags;
if (likely(!child->perf_event_ctxp)) {
perf_event_task(child, NULL, 0);
return;
}
local_irq_save(flags);
/*
* We can't reschedule here because interrupts are disabled,
* and either child is current or it is a task that can't be
* scheduled, so we are now safe from rescheduling changing
* our context.
*/
child_ctx = child->perf_event_ctxp;
__perf_event_task_sched_out(child_ctx);
/*
* Take the context lock here so that if find_get_context is
* reading child->perf_event_ctxp, we wait until it has
* incremented the context's refcount before we do put_ctx below.
*/
raw_spin_lock(&child_ctx->lock);
child->perf_event_ctxp = NULL;
/*
* If this context is a clone; unclone it so it can't get
* swapped to another process while we're removing all
* the events from it.
*/
unclone_ctx(child_ctx);
update_context_time(child_ctx);
raw_spin_unlock_irqrestore(&child_ctx->lock, flags);
/*
* Report the task dead after unscheduling the events so that we
* won't get any samples after PERF_RECORD_EXIT. We can however still
* get a few PERF_RECORD_READ events.
*/
perf_event_task(child, child_ctx, 0);
/*
* We can recurse on the same lock type through:
*
* __perf_event_exit_task()
* sync_child_event()
* fput(parent_event->filp)
* perf_release()
* mutex_lock(&ctx->mutex)
*
* But since its the parent context it won't be the same instance.
*/
mutex_lock_nested(&child_ctx->mutex, SINGLE_DEPTH_NESTING);
again:
list_for_each_entry_safe(child_event, tmp, &child_ctx->group_list,
group_entry)
__perf_event_exit_task(child_event, child_ctx, child);
/*
* If the last event was a group event, it will have appended all
* its siblings to the list, but we obtained 'tmp' before that which
* will still point to the list head terminating the iteration.
*/
if (!list_empty(&child_ctx->group_list))
goto again;
mutex_unlock(&child_ctx->mutex);
put_ctx(child_ctx);
}
/*
* free an unexposed, unused context as created by inheritance by
* init_task below, used by fork() in case of fail.
*/
void perf_event_free_task(struct task_struct *task)
{
struct perf_event_context *ctx = task->perf_event_ctxp;
struct perf_event *event, *tmp;
if (!ctx)
return;
mutex_lock(&ctx->mutex);
again:
list_for_each_entry_safe(event, tmp, &ctx->group_list, group_entry) {
struct perf_event *parent = event->parent;
if (WARN_ON_ONCE(!parent))
continue;
mutex_lock(&parent->child_mutex);
list_del_init(&event->child_list);
mutex_unlock(&parent->child_mutex);
fput(parent->filp);
list_del_event(event, ctx);
free_event(event);
}
if (!list_empty(&ctx->group_list))
goto again;
mutex_unlock(&ctx->mutex);
put_ctx(ctx);
}
/*
* Initialize the perf_event context in task_struct
*/
int perf_event_init_task(struct task_struct *child)
{
struct perf_event_context *child_ctx = NULL, *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->group_list, group_entry) {
if (!event->attr.inherit) {
inherited_all = 0;
continue;
}
if (!child->perf_event_ctxp) {
/*
* 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) {
ret = -ENOMEM;
break;
}
__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;
break;
}
}
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);
__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);
hw_perf_event_setup(cpu);
}
#ifdef CONFIG_HOTPLUG_CPU
static void __perf_event_exit_cpu(void *info)
{
struct perf_cpu_context *cpuctx = &__get_cpu_var(perf_cpu_context);
struct perf_event_context *ctx = &cpuctx->ctx;
struct perf_event *event, *tmp;
list_for_each_entry_safe(event, tmp, &ctx->group_list, group_entry)
__perf_event_remove_from_context(event);
}
static void perf_event_exit_cpu(int cpu)
{
struct perf_cpu_context *cpuctx = &per_cpu(perf_cpu_context, cpu);
struct perf_event_context *ctx = &cpuctx->ctx;
mutex_lock(&ctx->mutex);
smp_call_function_single(cpu, __perf_event_exit_cpu, NULL, 1);
mutex_unlock(&ctx->mutex);
}
#else
static inline void perf_event_exit_cpu(int cpu) { }
#endif
static int __cpuinit
perf_cpu_notify(struct notifier_block *self, unsigned long action, void *hcpu)
{
unsigned int cpu = (long)hcpu;
switch (action) {
case CPU_UP_PREPARE:
case CPU_UP_PREPARE_FROZEN:
perf_event_init_cpu(cpu);
break;
case CPU_ONLINE:
case CPU_ONLINE_FROZEN:
hw_perf_event_setup_online(cpu);
break;
case CPU_DOWN_PREPARE:
case CPU_DOWN_PREPARE_FROZEN:
perf_event_exit_cpu(cpu);
break;
default:
break;
}
return NOTIFY_OK;
}
/*
* This has to have a higher priority than migration_notifier in sched.c.
*/
static struct notifier_block __cpuinitdata perf_cpu_nb = {
.notifier_call = perf_cpu_notify,
.priority = 20,
};
void __init perf_event_init(void)
{
perf_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, char *buf)
{
return sprintf(buf, "%d\n", perf_reserved_percpu);
}
static ssize_t
perf_set_reserve_percpu(struct sysdev_class *class,
const char *buf,
size_t count)
{
struct perf_cpu_context *cpuctx;
unsigned long val;
int err, cpu, mpt;
err = strict_strtoul(buf, 10, &val);
if (err)
return err;
if (val > perf_max_events)
return -EINVAL;
spin_lock(&perf_resource_lock);
perf_reserved_percpu = val;
for_each_online_cpu(cpu) {
cpuctx = &per_cpu(perf_cpu_context, cpu);
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, char *buf)
{
return sprintf(buf, "%d\n", perf_overcommit);
}
static ssize_t
perf_set_overcommit(struct sysdev_class *class, const char *buf, size_t count)
{
unsigned long val;
int err;
err = strict_strtoul(buf, 10, &val);
if (err)
return err;
if (val > 1)
return -EINVAL;
spin_lock(&perf_resource_lock);
perf_overcommit = val;
spin_unlock(&perf_resource_lock);
return count;
}
static SYSDEV_CLASS_ATTR(
reserve_percpu,
0644,
perf_show_reserve_percpu,
perf_set_reserve_percpu
);
static SYSDEV_CLASS_ATTR(
overcommit,
0644,
perf_show_overcommit,
perf_set_overcommit
);
static struct attribute *perfclass_attrs[] = {
&attr_reserve_percpu.attr,
&attr_overcommit.attr,
NULL
};
static struct attribute_group perfclass_attr_group = {
.attrs = perfclass_attrs,
.name = "perf_events",
};
static int __init perf_event_sysfs_init(void)
{
return sysfs_create_group(&cpu_sysdev_class.kset.kobj,
&perfclass_attr_group);
}
device_initcall(perf_event_sysfs_init);