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-rw-r--r--kernel/perf_counter.c4861
1 files changed, 0 insertions, 4861 deletions
diff --git a/kernel/perf_counter.c b/kernel/perf_counter.c
deleted file mode 100644
index d7cbc579fc8..00000000000
--- a/kernel/perf_counter.c
+++ /dev/null
@@ -1,4861 +0,0 @@
-/*
- * Performance counter core code
- *
- * Copyright (C) 2008 Thomas Gleixner <tglx@linutronix.de>
- * Copyright (C) 2008-2009 Red Hat, Inc., Ingo Molnar
- * Copyright (C) 2008-2009 Red Hat, Inc., Peter Zijlstra <pzijlstr@redhat.com>
- * Copyright © 2009 Paul Mackerras, IBM Corp. <paulus@au1.ibm.com>
- *
- * For licensing details see kernel-base/COPYING
- */
-
-#include <linux/fs.h>
-#include <linux/mm.h>
-#include <linux/cpu.h>
-#include <linux/smp.h>
-#include <linux/file.h>
-#include <linux/poll.h>
-#include <linux/sysfs.h>
-#include <linux/dcache.h>
-#include <linux/percpu.h>
-#include <linux/ptrace.h>
-#include <linux/vmstat.h>
-#include <linux/hardirq.h>
-#include <linux/rculist.h>
-#include <linux/uaccess.h>
-#include <linux/syscalls.h>
-#include <linux/anon_inodes.h>
-#include <linux/kernel_stat.h>
-#include <linux/perf_counter.h>
-
-#include <asm/irq_regs.h>
-
-/*
- * Each CPU has a list of per CPU counters:
- */
-DEFINE_PER_CPU(struct perf_cpu_context, perf_cpu_context);
-
-int perf_max_counters __read_mostly = 1;
-static int perf_reserved_percpu __read_mostly;
-static int perf_overcommit __read_mostly = 1;
-
-static atomic_t nr_counters __read_mostly;
-static atomic_t nr_mmap_counters __read_mostly;
-static atomic_t nr_comm_counters __read_mostly;
-static atomic_t nr_task_counters __read_mostly;
-
-/*
- * perf counter paranoia level:
- * 0 - not paranoid
- * 1 - disallow cpu counters to unpriv
- * 2 - disallow kernel profiling to unpriv
- */
-int sysctl_perf_counter_paranoid __read_mostly = 1;
-
-static inline bool perf_paranoid_cpu(void)
-{
- return sysctl_perf_counter_paranoid > 0;
-}
-
-static inline bool perf_paranoid_kernel(void)
-{
- return sysctl_perf_counter_paranoid > 1;
-}
-
-int sysctl_perf_counter_mlock __read_mostly = 512; /* 'free' kb per user */
-
-/*
- * max perf counter sample rate
- */
-int sysctl_perf_counter_sample_rate __read_mostly = 100000;
-
-static atomic64_t perf_counter_id;
-
-/*
- * Lock for (sysadmin-configurable) counter reservations:
- */
-static DEFINE_SPINLOCK(perf_resource_lock);
-
-/*
- * Architecture provided APIs - weak aliases:
- */
-extern __weak const struct pmu *hw_perf_counter_init(struct perf_counter *counter)
-{
- return NULL;
-}
-
-void __weak hw_perf_disable(void) { barrier(); }
-void __weak hw_perf_enable(void) { barrier(); }
-
-void __weak hw_perf_counter_setup(int cpu) { barrier(); }
-void __weak hw_perf_counter_setup_online(int cpu) { barrier(); }
-
-int __weak
-hw_perf_group_sched_in(struct perf_counter *group_leader,
- struct perf_cpu_context *cpuctx,
- struct perf_counter_context *ctx, int cpu)
-{
- return 0;
-}
-
-void __weak perf_counter_print_debug(void) { }
-
-static DEFINE_PER_CPU(int, disable_count);
-
-void __perf_disable(void)
-{
- __get_cpu_var(disable_count)++;
-}
-
-bool __perf_enable(void)
-{
- return !--__get_cpu_var(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_counter_context *ctx)
-{
- WARN_ON(!atomic_inc_not_zero(&ctx->refcount));
-}
-
-static void free_ctx(struct rcu_head *head)
-{
- struct perf_counter_context *ctx;
-
- ctx = container_of(head, struct perf_counter_context, rcu_head);
- kfree(ctx);
-}
-
-static void put_ctx(struct perf_counter_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_counter_context *ctx)
-{
- if (ctx->parent_ctx) {
- put_ctx(ctx->parent_ctx);
- ctx->parent_ctx = NULL;
- }
-}
-
-/*
- * If we inherit counters we want to return the parent counter id
- * to userspace.
- */
-static u64 primary_counter_id(struct perf_counter *counter)
-{
- u64 id = counter->id;
-
- if (counter->parent)
- id = counter->parent->id;
-
- return id;
-}
-
-/*
- * Get the perf_counter_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_counter_context *
-perf_lock_task_context(struct task_struct *task, unsigned long *flags)
-{
- struct perf_counter_context *ctx;
-
- rcu_read_lock();
- retry:
- ctx = rcu_dereference(task->perf_counter_ctxp);
- if (ctx) {
- /*
- * If this context is a clone of another, it might
- * get swapped for another underneath us by
- * perf_counter_task_sched_out, though the
- * rcu_read_lock() protects us from any context
- * getting freed. Lock the context and check if it
- * got swapped before we could get the lock, and retry
- * if so. If we locked the right context, then it
- * can't get swapped on us any more.
- */
- spin_lock_irqsave(&ctx->lock, *flags);
- if (ctx != rcu_dereference(task->perf_counter_ctxp)) {
- spin_unlock_irqrestore(&ctx->lock, *flags);
- goto retry;
- }
-
- if (!atomic_inc_not_zero(&ctx->refcount)) {
- spin_unlock_irqrestore(&ctx->lock, *flags);
- ctx = NULL;
- }
- }
- rcu_read_unlock();
- return ctx;
-}
-
-/*
- * Get the context for a task and increment its pin_count so it
- * can't get swapped to another task. This also increments its
- * reference count so that the context can't get freed.
- */
-static struct perf_counter_context *perf_pin_task_context(struct task_struct *task)
-{
- struct perf_counter_context *ctx;
- unsigned long flags;
-
- ctx = perf_lock_task_context(task, &flags);
- if (ctx) {
- ++ctx->pin_count;
- spin_unlock_irqrestore(&ctx->lock, flags);
- }
- return ctx;
-}
-
-static void perf_unpin_context(struct perf_counter_context *ctx)
-{
- unsigned long flags;
-
- spin_lock_irqsave(&ctx->lock, flags);
- --ctx->pin_count;
- spin_unlock_irqrestore(&ctx->lock, flags);
- put_ctx(ctx);
-}
-
-/*
- * Add a counter from the lists for its context.
- * Must be called with ctx->mutex and ctx->lock held.
- */
-static void
-list_add_counter(struct perf_counter *counter, struct perf_counter_context *ctx)
-{
- struct perf_counter *group_leader = counter->group_leader;
-
- /*
- * Depending on whether it is a standalone or sibling counter,
- * add it straight to the context's counter list, or to the group
- * leader's sibling list:
- */
- if (group_leader == counter)
- list_add_tail(&counter->list_entry, &ctx->counter_list);
- else {
- list_add_tail(&counter->list_entry, &group_leader->sibling_list);
- group_leader->nr_siblings++;
- }
-
- list_add_rcu(&counter->event_entry, &ctx->event_list);
- ctx->nr_counters++;
- if (counter->attr.inherit_stat)
- ctx->nr_stat++;
-}
-
-/*
- * Remove a counter from the lists for its context.
- * Must be called with ctx->mutex and ctx->lock held.
- */
-static void
-list_del_counter(struct perf_counter *counter, struct perf_counter_context *ctx)
-{
- struct perf_counter *sibling, *tmp;
-
- if (list_empty(&counter->list_entry))
- return;
- ctx->nr_counters--;
- if (counter->attr.inherit_stat)
- ctx->nr_stat--;
-
- list_del_init(&counter->list_entry);
- list_del_rcu(&counter->event_entry);
-
- if (counter->group_leader != counter)
- counter->group_leader->nr_siblings--;
-
- /*
- * If this was a group counter with sibling counters then
- * upgrade the siblings to singleton counters by adding them
- * to the context list directly:
- */
- list_for_each_entry_safe(sibling, tmp,
- &counter->sibling_list, list_entry) {
-
- list_move_tail(&sibling->list_entry, &ctx->counter_list);
- sibling->group_leader = sibling;
- }
-}
-
-static void
-counter_sched_out(struct perf_counter *counter,
- struct perf_cpu_context *cpuctx,
- struct perf_counter_context *ctx)
-{
- if (counter->state != PERF_COUNTER_STATE_ACTIVE)
- return;
-
- counter->state = PERF_COUNTER_STATE_INACTIVE;
- if (counter->pending_disable) {
- counter->pending_disable = 0;
- counter->state = PERF_COUNTER_STATE_OFF;
- }
- counter->tstamp_stopped = ctx->time;
- counter->pmu->disable(counter);
- counter->oncpu = -1;
-
- if (!is_software_counter(counter))
- cpuctx->active_oncpu--;
- ctx->nr_active--;
- if (counter->attr.exclusive || !cpuctx->active_oncpu)
- cpuctx->exclusive = 0;
-}
-
-static void
-group_sched_out(struct perf_counter *group_counter,
- struct perf_cpu_context *cpuctx,
- struct perf_counter_context *ctx)
-{
- struct perf_counter *counter;
-
- if (group_counter->state != PERF_COUNTER_STATE_ACTIVE)
- return;
-
- counter_sched_out(group_counter, cpuctx, ctx);
-
- /*
- * Schedule out siblings (if any):
- */
- list_for_each_entry(counter, &group_counter->sibling_list, list_entry)
- counter_sched_out(counter, cpuctx, ctx);
-
- if (group_counter->attr.exclusive)
- cpuctx->exclusive = 0;
-}
-
-/*
- * Cross CPU call to remove a performance counter
- *
- * We disable the counter on the hardware level first. After that we
- * remove it from the context list.
- */
-static void __perf_counter_remove_from_context(void *info)
-{
- struct perf_cpu_context *cpuctx = &__get_cpu_var(perf_cpu_context);
- struct perf_counter *counter = info;
- struct perf_counter_context *ctx = counter->ctx;
-
- /*
- * If this is a task context, we need to check whether it is
- * the current task context of this cpu. If not it has been
- * scheduled out before the smp call arrived.
- */
- if (ctx->task && cpuctx->task_ctx != ctx)
- return;
-
- spin_lock(&ctx->lock);
- /*
- * Protect the list operation against NMI by disabling the
- * counters on a global level.
- */
- perf_disable();
-
- counter_sched_out(counter, cpuctx, ctx);
-
- list_del_counter(counter, ctx);
-
- if (!ctx->task) {
- /*
- * Allow more per task counters with respect to the
- * reservation:
- */
- cpuctx->max_pertask =
- min(perf_max_counters - ctx->nr_counters,
- perf_max_counters - perf_reserved_percpu);
- }
-
- perf_enable();
- spin_unlock(&ctx->lock);
-}
-
-
-/*
- * Remove the counter from a task's (or a CPU's) list of counters.
- *
- * Must be called with ctx->mutex held.
- *
- * CPU counters are removed with a smp call. For task counters we only
- * call when the task is on a CPU.
- *
- * If counter->ctx is a cloned context, callers must make sure that
- * every task struct that counter->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_counter_exit_task, it's OK because the
- * context has been detached from its task.
- */
-static void perf_counter_remove_from_context(struct perf_counter *counter)
-{
- struct perf_counter_context *ctx = counter->ctx;
- struct task_struct *task = ctx->task;
-
- if (!task) {
- /*
- * Per cpu counters are removed via an smp call and
- * the removal is always sucessful.
- */
- smp_call_function_single(counter->cpu,
- __perf_counter_remove_from_context,
- counter, 1);
- return;
- }
-
-retry:
- task_oncpu_function_call(task, __perf_counter_remove_from_context,
- counter);
-
- spin_lock_irq(&ctx->lock);
- /*
- * If the context is active we need to retry the smp call.
- */
- if (ctx->nr_active && !list_empty(&counter->list_entry)) {
- spin_unlock_irq(&ctx->lock);
- goto retry;
- }
-
- /*
- * The lock prevents that this context is scheduled in so we
- * can remove the counter safely, if the call above did not
- * succeed.
- */
- if (!list_empty(&counter->list_entry)) {
- list_del_counter(counter, ctx);
- }
- spin_unlock_irq(&ctx->lock);
-}
-
-static inline u64 perf_clock(void)
-{
- return cpu_clock(smp_processor_id());
-}
-
-/*
- * Update the record of the current time in a context.
- */
-static void update_context_time(struct perf_counter_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 counter.
- */
-static void update_counter_times(struct perf_counter *counter)
-{
- struct perf_counter_context *ctx = counter->ctx;
- u64 run_end;
-
- if (counter->state < PERF_COUNTER_STATE_INACTIVE)
- return;
-
- counter->total_time_enabled = ctx->time - counter->tstamp_enabled;
-
- if (counter->state == PERF_COUNTER_STATE_INACTIVE)
- run_end = counter->tstamp_stopped;
- else
- run_end = ctx->time;
-
- counter->total_time_running = run_end - counter->tstamp_running;
-}
-
-/*
- * Update total_time_enabled and total_time_running for all counters in a group.
- */
-static void update_group_times(struct perf_counter *leader)
-{
- struct perf_counter *counter;
-
- update_counter_times(leader);
- list_for_each_entry(counter, &leader->sibling_list, list_entry)
- update_counter_times(counter);
-}
-
-/*
- * Cross CPU call to disable a performance counter
- */
-static void __perf_counter_disable(void *info)
-{
- struct perf_counter *counter = info;
- struct perf_cpu_context *cpuctx = &__get_cpu_var(perf_cpu_context);
- struct perf_counter_context *ctx = counter->ctx;
-
- /*
- * If this is a per-task counter, need to check whether this
- * counter's task is the current task on this cpu.
- */
- if (ctx->task && cpuctx->task_ctx != ctx)
- return;
-
- spin_lock(&ctx->lock);
-
- /*
- * If the counter is on, turn it off.
- * If it is in error state, leave it in error state.
- */
- if (counter->state >= PERF_COUNTER_STATE_INACTIVE) {
- update_context_time(ctx);
- update_counter_times(counter);
- if (counter == counter->group_leader)
- group_sched_out(counter, cpuctx, ctx);
- else
- counter_sched_out(counter, cpuctx, ctx);
- counter->state = PERF_COUNTER_STATE_OFF;
- }
-
- spin_unlock(&ctx->lock);
-}
-
-/*
- * Disable a counter.
- *
- * If counter->ctx is a cloned context, callers must make sure that
- * every task struct that counter->ctx->task could possibly point to
- * remains valid. This condition is satisifed when called through
- * perf_counter_for_each_child or perf_counter_for_each because they
- * hold the top-level counter's child_mutex, so any descendant that
- * goes to exit will block in sync_child_counter.
- * When called from perf_pending_counter it's OK because counter->ctx
- * is the current context on this CPU and preemption is disabled,
- * hence we can't get into perf_counter_task_sched_out for this context.
- */
-static void perf_counter_disable(struct perf_counter *counter)
-{
- struct perf_counter_context *ctx = counter->ctx;
- struct task_struct *task = ctx->task;
-
- if (!task) {
- /*
- * Disable the counter on the cpu that it's on
- */
- smp_call_function_single(counter->cpu, __perf_counter_disable,
- counter, 1);
- return;
- }
-
- retry:
- task_oncpu_function_call(task, __perf_counter_disable, counter);
-
- spin_lock_irq(&ctx->lock);
- /*
- * If the counter is still active, we need to retry the cross-call.
- */
- if (counter->state == PERF_COUNTER_STATE_ACTIVE) {
- spin_unlock_irq(&ctx->lock);
- goto retry;
- }
-
- /*
- * Since we have the lock this context can't be scheduled
- * in, so we can change the state safely.
- */
- if (counter->state == PERF_COUNTER_STATE_INACTIVE) {
- update_counter_times(counter);
- counter->state = PERF_COUNTER_STATE_OFF;
- }
-
- spin_unlock_irq(&ctx->lock);
-}
-
-static int
-counter_sched_in(struct perf_counter *counter,
- struct perf_cpu_context *cpuctx,
- struct perf_counter_context *ctx,
- int cpu)
-{
- if (counter->state <= PERF_COUNTER_STATE_OFF)
- return 0;
-
- counter->state = PERF_COUNTER_STATE_ACTIVE;
- counter->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 (counter->pmu->enable(counter)) {
- counter->state = PERF_COUNTER_STATE_INACTIVE;
- counter->oncpu = -1;
- return -EAGAIN;
- }
-
- counter->tstamp_running += ctx->time - counter->tstamp_stopped;
-
- if (!is_software_counter(counter))
- cpuctx->active_oncpu++;
- ctx->nr_active++;
-
- if (counter->attr.exclusive)
- cpuctx->exclusive = 1;
-
- return 0;
-}
-
-static int
-group_sched_in(struct perf_counter *group_counter,
- struct perf_cpu_context *cpuctx,
- struct perf_counter_context *ctx,
- int cpu)
-{
- struct perf_counter *counter, *partial_group;
- int ret;
-
- if (group_counter->state == PERF_COUNTER_STATE_OFF)
- return 0;
-
- ret = hw_perf_group_sched_in(group_counter, cpuctx, ctx, cpu);
- if (ret)
- return ret < 0 ? ret : 0;
-
- if (counter_sched_in(group_counter, cpuctx, ctx, cpu))
- return -EAGAIN;
-
- /*
- * Schedule in siblings as one group (if any):
- */
- list_for_each_entry(counter, &group_counter->sibling_list, list_entry) {
- if (counter_sched_in(counter, cpuctx, ctx, cpu)) {
- partial_group = counter;
- 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(counter, &group_counter->sibling_list, list_entry) {
- if (counter == partial_group)
- break;
- counter_sched_out(counter, cpuctx, ctx);
- }
- counter_sched_out(group_counter, cpuctx, ctx);
-
- return -EAGAIN;
-}
-
-/*
- * Return 1 for a group consisting entirely of software counters,
- * 0 if the group contains any hardware counters.
- */
-static int is_software_only_group(struct perf_counter *leader)
-{
- struct perf_counter *counter;
-
- if (!is_software_counter(leader))
- return 0;
-
- list_for_each_entry(counter, &leader->sibling_list, list_entry)
- if (!is_software_counter(counter))
- return 0;
-
- return 1;
-}
-
-/*
- * Work out whether we can put this counter group on the CPU now.
- */
-static int group_can_go_on(struct perf_counter *counter,
- struct perf_cpu_context *cpuctx,
- int can_add_hw)
-{
- /*
- * Groups consisting entirely of software counters can always go on.
- */
- if (is_software_only_group(counter))
- return 1;
- /*
- * If an exclusive group is already on, no other hardware
- * counters can go on.
- */
- if (cpuctx->exclusive)
- return 0;
- /*
- * If this group is exclusive and there are already
- * counters on the CPU, it can't go on.
- */
- if (counter->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_counter_to_ctx(struct perf_counter *counter,
- struct perf_counter_context *ctx)
-{
- list_add_counter(counter, ctx);
- counter->tstamp_enabled = ctx->time;
- counter->tstamp_running = ctx->time;
- counter->tstamp_stopped = ctx->time;
-}
-
-/*
- * Cross CPU call to install and enable a performance counter
- *
- * 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_counter *counter = info;
- struct perf_counter_context *ctx = counter->ctx;
- struct perf_counter *leader = counter->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 counters.
- */
- if (ctx->task && cpuctx->task_ctx != ctx) {
- if (cpuctx->task_ctx || ctx->task != current)
- return;
- cpuctx->task_ctx = ctx;
- }
-
- spin_lock(&ctx->lock);
- ctx->is_active = 1;
- update_context_time(ctx);
-
- /*
- * Protect the list operation against NMI by disabling the
- * counters on a global level. NOP for non NMI based counters.
- */
- perf_disable();
-
- add_counter_to_ctx(counter, ctx);
-
- /*
- * Don't put the counter on if it is disabled or if
- * it is in a group and the group isn't on.
- */
- if (counter->state != PERF_COUNTER_STATE_INACTIVE ||
- (leader != counter && leader->state != PERF_COUNTER_STATE_ACTIVE))
- goto unlock;
-
- /*
- * An exclusive counter can't go on if there are already active
- * hardware counters, and no hardware counter can go on if there
- * is already an exclusive counter on.
- */
- if (!group_can_go_on(counter, cpuctx, 1))
- err = -EEXIST;
- else
- err = counter_sched_in(counter, cpuctx, ctx, cpu);
-
- if (err) {
- /*
- * This counter couldn't go on. If it is in a group
- * then we have to pull the whole group off.
- * If the counter group is pinned then put it in error state.
- */
- if (leader != counter)
- group_sched_out(leader, cpuctx, ctx);
- if (leader->attr.pinned) {
- update_group_times(leader);
- leader->state = PERF_COUNTER_STATE_ERROR;
- }
- }
-
- if (!err && !ctx->task && cpuctx->max_pertask)
- cpuctx->max_pertask--;
-
- unlock:
- perf_enable();
-
- spin_unlock(&ctx->lock);
-}
-
-/*
- * Attach a performance counter to a context
- *
- * First we add the counter to the list with the hardware enable bit
- * in counter->hw_config cleared.
- *
- * If the counter 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_counter_context *ctx,
- struct perf_counter *counter,
- int cpu)
-{
- struct task_struct *task = ctx->task;
-
- if (!task) {
- /*
- * Per cpu counters are installed via an smp call and
- * the install is always sucessful.
- */
- smp_call_function_single(cpu, __perf_install_in_context,
- counter, 1);
- return;
- }
-
-retry:
- task_oncpu_function_call(task, __perf_install_in_context,
- counter);
-
- spin_lock_irq(&ctx->lock);
- /*
- * we need to retry the smp call.
- */
- if (ctx->is_active && list_empty(&counter->list_entry)) {
- spin_unlock_irq(&ctx->lock);
- goto retry;
- }
-
- /*
- * The lock prevents that this context is scheduled in so we
- * can add the counter safely, if it the call above did not
- * succeed.
- */
- if (list_empty(&counter->list_entry))
- add_counter_to_ctx(counter, ctx);
- spin_unlock_irq(&ctx->lock);
-}
-
-/*
- * Cross CPU call to enable a performance counter
- */
-static void __perf_counter_enable(void *info)
-{
- struct perf_counter *counter = info;
- struct perf_cpu_context *cpuctx = &__get_cpu_var(perf_cpu_context);
- struct perf_counter_context *ctx = counter->ctx;
- struct perf_counter *leader = counter->group_leader;
- int err;
-
- /*
- * If this is a per-task counter, need to check whether this
- * counter's task is the current task on this cpu.
- */
- if (ctx->task && cpuctx->task_ctx != ctx) {
- if (cpuctx->task_ctx || ctx->task != current)
- return;
- cpuctx->task_ctx = ctx;
- }
-
- spin_lock(&ctx->lock);
- ctx->is_active = 1;
- update_context_time(ctx);
-
- if (counter->state >= PERF_COUNTER_STATE_INACTIVE)
- goto unlock;
- counter->state = PERF_COUNTER_STATE_INACTIVE;
- counter->tstamp_enabled = ctx->time - counter->total_time_enabled;
-
- /*
- * If the counter is in a group and isn't the group leader,
- * then don't put it on unless the group is on.
- */
- if (leader != counter && leader->state != PERF_COUNTER_STATE_ACTIVE)
- goto unlock;
-
- if (!group_can_go_on(counter, cpuctx, 1)) {
- err = -EEXIST;
- } else {
- perf_disable();
- if (counter == leader)
- err = group_sched_in(counter, cpuctx, ctx,
- smp_processor_id());
- else
- err = counter_sched_in(counter, cpuctx, ctx,
- smp_processor_id());
- perf_enable();
- }
-
- if (err) {
- /*
- * If this counter can't go on and it's part of a
- * group, then the whole group has to come off.
- */
- if (leader != counter)
- group_sched_out(leader, cpuctx, ctx);
- if (leader->attr.pinned) {
- update_group_times(leader);
- leader->state = PERF_COUNTER_STATE_ERROR;
- }
- }
-
- unlock:
- spin_unlock(&ctx->lock);
-}
-
-/*
- * Enable a counter.
- *
- * If counter->ctx is a cloned context, callers must make sure that
- * every task struct that counter->ctx->task could possibly point to
- * remains valid. This condition is satisfied when called through
- * perf_counter_for_each_child or perf_counter_for_each as described
- * for perf_counter_disable.
- */
-static void perf_counter_enable(struct perf_counter *counter)
-{
- struct perf_counter_context *ctx = counter->ctx;
- struct task_struct *task = ctx->task;
-
- if (!task) {
- /*
- * Enable the counter on the cpu that it's on
- */
- smp_call_function_single(counter->cpu, __perf_counter_enable,
- counter, 1);
- return;
- }
-
- spin_lock_irq(&ctx->lock);
- if (counter->state >= PERF_COUNTER_STATE_INACTIVE)
- goto out;
-
- /*
- * If the counter is in error state, clear that first.
- * That way, if we see the counter 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 (counter->state == PERF_COUNTER_STATE_ERROR)
- counter->state = PERF_COUNTER_STATE_OFF;
-
- retry:
- spin_unlock_irq(&ctx->lock);
- task_oncpu_function_call(task, __perf_counter_enable, counter);
-
- spin_lock_irq(&ctx->lock);
-
- /*
- * If the context is active and the counter is still off,
- * we need to retry the cross-call.
- */
- if (ctx->is_active && counter->state == PERF_COUNTER_STATE_OFF)
- goto retry;
-
- /*
- * Since we have the lock this context can't be scheduled
- * in, so we can change the state safely.
- */
- if (counter->state == PERF_COUNTER_STATE_OFF) {
- counter->state = PERF_COUNTER_STATE_INACTIVE;
- counter->tstamp_enabled =
- ctx->time - counter->total_time_enabled;
- }
- out:
- spin_unlock_irq(&ctx->lock);
-}
-
-static int perf_counter_refresh(struct perf_counter *counter, int refresh)
-{
- /*
- * not supported on inherited counters
- */
- if (counter->attr.inherit)
- return -EINVAL;
-
- atomic_add(refresh, &counter->event_limit);
- perf_counter_enable(counter);
-
- return 0;
-}
-
-void __perf_counter_sched_out(struct perf_counter_context *ctx,
- struct perf_cpu_context *cpuctx)
-{
- struct perf_counter *counter;
-
- spin_lock(&ctx->lock);
- ctx->is_active = 0;
- if (likely(!ctx->nr_counters))
- goto out;
- update_context_time(ctx);
-
- perf_disable();
- if (ctx->nr_active) {
- list_for_each_entry(counter, &ctx->counter_list, list_entry) {
- if (counter != counter->group_leader)
- counter_sched_out(counter, cpuctx, ctx);
- else
- group_sched_out(counter, cpuctx, ctx);
- }
- }
- perf_enable();
- out:
- spin_unlock(&ctx->lock);
-}
-
-/*
- * Test whether two contexts are equivalent, i.e. whether they
- * have both been cloned from the same version of the same context
- * and they both have the same number of enabled counters.
- * If the number of enabled counters is the same, then the set
- * of enabled counters should be the same, because these are both
- * inherited contexts, therefore we can't access individual counters
- * in them directly with an fd; we can only enable/disable all
- * counters via prctl, or enable/disable all counters in a family
- * via ioctl, which will have the same effect on both contexts.
- */
-static int context_equiv(struct perf_counter_context *ctx1,
- struct perf_counter_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_counter_read(void *counter);
-
-static void __perf_counter_sync_stat(struct perf_counter *counter,
- struct perf_counter *next_counter)
-{
- u64 value;
-
- if (!counter->attr.inherit_stat)
- return;
-
- /*
- * Update the counter value, we cannot use perf_counter_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 counter must be on the current CPU, therefore we
- * don't need to use it.
- */
- switch (counter->state) {
- case PERF_COUNTER_STATE_ACTIVE:
- __perf_counter_read(counter);
- break;
-
- case PERF_COUNTER_STATE_INACTIVE:
- update_counter_times(counter);
- break;
-
- default:
- break;
- }
-
- /*
- * In order to keep per-task stats reliable we need to flip the counter
- * values when we flip the contexts.
- */
- value = atomic64_read(&next_counter->count);
- value = atomic64_xchg(&counter->count, value);
- atomic64_set(&next_counter->count, value);
-
- swap(counter->total_time_enabled, next_counter->total_time_enabled);
- swap(counter->total_time_running, next_counter->total_time_running);
-
- /*
- * Since we swizzled the values, update the user visible data too.
- */
- perf_counter_update_userpage(counter);
- perf_counter_update_userpage(next_counter);
-}
-
-#define list_next_entry(pos, member) \
- list_entry(pos->member.next, typeof(*pos), member)
-
-static void perf_counter_sync_stat(struct perf_counter_context *ctx,
- struct perf_counter_context *next_ctx)
-{
- struct perf_counter *counter, *next_counter;
-
- if (!ctx->nr_stat)
- return;
-
- counter = list_first_entry(&ctx->event_list,
- struct perf_counter, event_entry);
-
- next_counter = list_first_entry(&next_ctx->event_list,
- struct perf_counter, event_entry);
-
- while (&counter->event_entry != &ctx->event_list &&
- &next_counter->event_entry != &next_ctx->event_list) {
-
- __perf_counter_sync_stat(counter, next_counter);
-
- counter = list_next_entry(counter, event_entry);
- next_counter = list_next_entry(next_counter, event_entry);
- }
-}
-
-/*
- * Called from scheduler to remove the counters of the current task,
- * with interrupts disabled.
- *
- * We stop each counter and update the counter value in counter->count.
- *
- * This does not protect us against NMI, but disable()
- * sets the disabled bit in the control field of counter _before_
- * accessing the counter control register. If a NMI hits, then it will
- * not restart the counter.
- */
-void perf_counter_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_counter_context *ctx = task->perf_counter_ctxp;
- struct perf_counter_context *next_ctx;
- struct perf_counter_context *parent;
- struct pt_regs *regs;
- int do_switch = 1;
-
- regs = task_pt_regs(task);
- perf_swcounter_event(PERF_COUNT_SW_CONTEXT_SWITCHES, 1, 1, regs, 0);
-
- if (likely(!ctx || !cpuctx->task_ctx))
- return;
-
- update_context_time(ctx);
-
- rcu_read_lock();
- parent = rcu_dereference(ctx->parent_ctx);
- next_ctx = next->perf_counter_ctxp;
- if (parent && next_ctx &&
- rcu_dereference(next_ctx->parent_ctx) == parent) {
- /*
- * Looks like the two contexts are clones, so we might be
- * able to optimize the context switch. We lock both
- * contexts and check that they are clones under the
- * lock (including re-checking that neither has been
- * uncloned in the meantime). It doesn't matter which
- * order we take the locks because no other cpu could
- * be trying to lock both of these tasks.
- */
- spin_lock(&ctx->lock);
- spin_lock_nested(&next_ctx->lock, SINGLE_DEPTH_NESTING);
- if (context_equiv(ctx, next_ctx)) {
- /*
- * XXX do we need a memory barrier of sorts
- * wrt to rcu_dereference() of perf_counter_ctxp
- */
- task->perf_counter_ctxp = next_ctx;
- next->perf_counter_ctxp = ctx;
- ctx->task = next;
- next_ctx->task = task;
- do_switch = 0;
-
- perf_counter_sync_stat(ctx, next_ctx);
- }
- spin_unlock(&next_ctx->lock);
- spin_unlock(&ctx->lock);
- }
- rcu_read_unlock();
-
- if (do_switch) {
- __perf_counter_sched_out(ctx, cpuctx);
- cpuctx->task_ctx = NULL;
- }
-}
-
-/*
- * Called with IRQs disabled
- */
-static void __perf_counter_task_sched_out(struct perf_counter_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_counter_sched_out(ctx, cpuctx);
- cpuctx->task_ctx = NULL;
-}
-
-/*
- * Called with IRQs disabled
- */
-static void perf_counter_cpu_sched_out(struct perf_cpu_context *cpuctx)
-{
- __perf_counter_sched_out(&cpuctx->ctx, cpuctx);
-}
-
-static void
-__perf_counter_sched_in(struct perf_counter_context *ctx,
- struct perf_cpu_context *cpuctx, int cpu)
-{
- struct perf_counter *counter;
- int can_add_hw = 1;
-
- spin_lock(&ctx->lock);
- ctx->is_active = 1;
- if (likely(!ctx->nr_counters))
- 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(counter, &ctx->counter_list, list_entry) {
- if (counter->state <= PERF_COUNTER_STATE_OFF ||
- !counter->attr.pinned)
- continue;
- if (counter->cpu != -1 && counter->cpu != cpu)
- continue;
-
- if (counter != counter->group_leader)
- counter_sched_in(counter, cpuctx, ctx, cpu);
- else {
- if (group_can_go_on(counter, cpuctx, 1))
- group_sched_in(counter, cpuctx, ctx, cpu);
- }
-
- /*
- * If this pinned group hasn't been scheduled,
- * put it in error state.
- */
- if (counter->state == PERF_COUNTER_STATE_INACTIVE) {
- update_group_times(counter);
- counter->state = PERF_COUNTER_STATE_ERROR;
- }
- }
-
- list_for_each_entry(counter, &ctx->counter_list, list_entry) {
- /*
- * Ignore counters in OFF or ERROR state, and
- * ignore pinned counters since we did them already.
- */
- if (counter->state <= PERF_COUNTER_STATE_OFF ||
- counter->attr.pinned)
- continue;
-
- /*
- * Listen to the 'cpu' scheduling filter constraint
- * of counters:
- */
- if (counter->cpu != -1 && counter->cpu != cpu)
- continue;
-
- if (counter != counter->group_leader) {
- if (counter_sched_in(counter, cpuctx, ctx, cpu))
- can_add_hw = 0;
- } else {
- if (group_can_go_on(counter, cpuctx, can_add_hw)) {
- if (group_sched_in(counter, cpuctx, ctx, cpu))
- can_add_hw = 0;
- }
- }
- }
- perf_enable();
- out:
- spin_unlock(&ctx->lock);
-}
-
-/*
- * Called from scheduler to add the counters of the current task
- * with interrupts disabled.
- *
- * We restore the counter value and then enable it.
- *
- * This does not protect us against NMI, but enable()
- * sets the enabled bit in the control field of counter _before_
- * accessing the counter control register. If a NMI hits, then it will
- * keep the counter running.
- */
-void perf_counter_task_sched_in(struct task_struct *task, int cpu)
-{
- struct perf_cpu_context *cpuctx = &per_cpu(perf_cpu_context, cpu);
- struct perf_counter_context *ctx = task->perf_counter_ctxp;
-
- if (likely(!ctx))
- return;
- if (cpuctx->task_ctx == ctx)
- return;
- __perf_counter_sched_in(ctx, cpuctx, cpu);
- cpuctx->task_ctx = ctx;
-}
-
-static void perf_counter_cpu_sched_in(struct perf_cpu_context *cpuctx, int cpu)
-{
- struct perf_counter_context *ctx = &cpuctx->ctx;
-
- __perf_counter_sched_in(ctx, cpuctx, cpu);
-}
-
-#define MAX_INTERRUPTS (~0ULL)
-
-static void perf_log_throttle(struct perf_counter *counter, int enable);
-
-static void perf_adjust_period(struct perf_counter *counter, u64 events)
-{
- struct hw_perf_counter *hwc = &counter->hw;
- u64 period, sample_period;
- s64 delta;
-
- events *= hwc->sample_period;
- period = div64_u64(events, counter->attr.sample_freq);
-
- delta = (s64)(period - hwc->sample_period);
- delta = (delta + 7) / 8; /* low pass filter */
-
- sample_period = hwc->sample_period + delta;
-
- if (!sample_period)
- sample_period = 1;
-
- hwc->sample_period = sample_period;
-}
-
-static void perf_ctx_adjust_freq(struct perf_counter_context *ctx)
-{
- struct perf_counter *counter;
- struct hw_perf_counter *hwc;
- u64 interrupts, freq;
-
- spin_lock(&ctx->lock);
- list_for_each_entry(counter, &ctx->counter_list, list_entry) {
- if (counter->state != PERF_COUNTER_STATE_ACTIVE)
- continue;
-
- hwc = &counter->hw;
-
- interrupts = hwc->interrupts;
- hwc->interrupts = 0;
-
- /*
- * unthrottle counters on the tick
- */
- if (interrupts == MAX_INTERRUPTS) {
- perf_log_throttle(counter, 1);
- counter->pmu->unthrottle(counter);
- interrupts = 2*sysctl_perf_counter_sample_rate/HZ;
- }
-
- if (!counter->attr.freq || !counter->attr.sample_freq)
- continue;
-
- /*
- * if the specified freq < HZ then we need to skip ticks
- */
- if (counter->attr.sample_freq < HZ) {
- freq = counter->attr.sample_freq;
-
- hwc->freq_count += freq;
- hwc->freq_interrupts += interrupts;
-
- if (hwc->freq_count < HZ)
- continue;
-
- interrupts = hwc->freq_interrupts;
- hwc->freq_interrupts = 0;
- hwc->freq_count -= HZ;
- } else
- freq = HZ;
-
- perf_adjust_period(counter, freq * interrupts);
-
- /*
- * In order to avoid being stalled by an (accidental) huge
- * sample period, force reset the sample period if we didn't
- * get any events in this freq period.
- */
- if (!interrupts) {
- perf_disable();
- counter->pmu->disable(counter);
- atomic64_set(&hwc->period_left, 0);
- counter->pmu->enable(counter);
- perf_enable();
- }
- }
- spin_unlock(&ctx->lock);
-}
-
-/*
- * Round-robin a context's counters:
- */
-static void rotate_ctx(struct perf_counter_context *ctx)
-{
- struct perf_counter *counter;
-
- if (!ctx->nr_counters)
- return;
-
- spin_lock(&ctx->lock);
- /*
- * Rotate the first entry last (works just fine for group counters too):
- */
- perf_disable();
- list_for_each_entry(counter, &ctx->counter_list, list_entry) {
- list_move_tail(&counter->list_entry, &ctx->counter_list);
- break;
- }
- perf_enable();
-
- spin_unlock(&ctx->lock);
-}
-
-void perf_counter_task_tick(struct task_struct *curr, int cpu)
-{
- struct perf_cpu_context *cpuctx;
- struct perf_counter_context *ctx;
-
- if (!atomic_read(&nr_counters))
- return;
-
- cpuctx = &per_cpu(perf_cpu_context, cpu);
- ctx = curr->perf_counter_ctxp;
-
- perf_ctx_adjust_freq(&cpuctx->ctx);
- if (ctx)
- perf_ctx_adjust_freq(ctx);
-
- perf_counter_cpu_sched_out(cpuctx);
- if (ctx)
- __perf_counter_task_sched_out(ctx);
-
- rotate_ctx(&cpuctx->ctx);
- if (ctx)
- rotate_ctx(ctx);
-
- perf_counter_cpu_sched_in(cpuctx, cpu);
- if (ctx)
- perf_counter_task_sched_in(curr, cpu);
-}
-
-/*
- * Enable all of a task's counters that have been marked enable-on-exec.
- * This expects task == current.
- */
-static void perf_counter_enable_on_exec(struct task_struct *task)
-{
- struct perf_counter_context *ctx;
- struct perf_counter *counter;
- unsigned long flags;
- int enabled = 0;
-
- local_irq_save(flags);
- ctx = task->perf_counter_ctxp;
- if (!ctx || !ctx->nr_counters)
- goto out;
-
- __perf_counter_task_sched_out(ctx);
-
- spin_lock(&ctx->lock);
-
- list_for_each_entry(counter, &ctx->counter_list, list_entry) {
- if (!counter->attr.enable_on_exec)
- continue;
- counter->attr.enable_on_exec = 0;
- if (counter->state >= PERF_COUNTER_STATE_INACTIVE)
- continue;
- counter->state = PERF_COUNTER_STATE_INACTIVE;
- counter->tstamp_enabled =
- ctx->time - counter->total_time_enabled;
- enabled = 1;
- }
-
- /*
- * Unclone this context if we enabled any counter.
- */
- if (enabled)
- unclone_ctx(ctx);
-
- spin_unlock(&ctx->lock);
-
- perf_counter_task_sched_in(task, smp_processor_id());
- out:
- local_irq_restore(flags);
-}
-
-/*
- * Cross CPU call to read the hardware counter
- */
-static void __perf_counter_read(void *info)
-{
- struct perf_cpu_context *cpuctx = &__get_cpu_var(perf_cpu_context);
- struct perf_counter *counter = info;
- struct perf_counter_context *ctx = counter->ctx;
- unsigned long flags;
-
- /*
- * If this is a task context, we need to check whether it is
- * the current task context of this cpu. If not it has been
- * scheduled out before the smp call arrived. In that case
- * counter->count would have been updated to a recent sample
- * when the counter was scheduled out.
- */
- if (ctx->task && cpuctx->task_ctx != ctx)
- return;
-
- local_irq_save(flags);
- if (ctx->is_active)
- update_context_time(ctx);
- counter->pmu->read(counter);
- update_counter_times(counter);
- local_irq_restore(flags);
-}
-
-static u64 perf_counter_read(struct perf_counter *counter)
-{
- /*
- * If counter is enabled and currently active on a CPU, update the
- * value in the counter structure:
- */
- if (counter->state == PERF_COUNTER_STATE_ACTIVE) {
- smp_call_function_single(counter->oncpu,
- __perf_counter_read, counter, 1);
- } else if (counter->state == PERF_COUNTER_STATE_INACTIVE) {
- update_counter_times(counter);
- }
-
- return atomic64_read(&counter->count);
-}
-
-/*
- * Initialize the perf_counter context in a task_struct:
- */
-static void
-__perf_counter_init_context(struct perf_counter_context *ctx,
- struct task_struct *task)
-{
- memset(ctx, 0, sizeof(*ctx));
- spin_lock_init(&ctx->lock);
- mutex_init(&ctx->mutex);
- INIT_LIST_HEAD(&ctx->counter_list);
- INIT_LIST_HEAD(&ctx->event_list);
- atomic_set(&ctx->refcount, 1);
- ctx->task = task;
-}
-
-static struct perf_counter_context *find_get_context(pid_t pid, int cpu)
-{
- struct perf_counter_context *ctx;
- struct perf_cpu_context *cpuctx;
- struct task_struct *task;
- unsigned long flags;
- int err;
-
- /*
- * If cpu is not a wildcard then this is a percpu counter:
- */
- if (cpu != -1) {
- /* Must be root to operate on a CPU counter: */
- if (perf_paranoid_cpu() && !capable(CAP_SYS_ADMIN))
- return ERR_PTR(-EACCES);
-
- if (cpu < 0 || cpu > num_possible_cpus())
- return ERR_PTR(-EINVAL);
-
- /*
- * We could be clever and allow to attach a counter to an
- * offline CPU and activate it when the CPU comes up, but
- * that's for later.
- */
- if (!cpu_isset(cpu, cpu_online_map))
- return ERR_PTR(-ENODEV);
-
- cpuctx = &per_cpu(perf_cpu_context, cpu);
- ctx = &cpuctx->ctx;
- get_ctx(ctx);
-
- return ctx;
- }
-
- rcu_read_lock();
- if (!pid)
- task = current;
- else
- task = find_task_by_vpid(pid);
- if (task)
- get_task_struct(task);
- rcu_read_unlock();
-
- if (!task)
- return ERR_PTR(-ESRCH);
-
- /*
- * Can't attach counters to a dying task.
- */
- err = -ESRCH;
- if (task->flags & PF_EXITING)
- goto errout;
-
- /* Reuse ptrace permission checks for now. */
- err = -EACCES;
- if (!ptrace_may_access(task, PTRACE_MODE_READ))
- goto errout;
-
- retry:
- ctx = perf_lock_task_context(task, &flags);
- if (ctx) {
- unclone_ctx(ctx);
- spin_unlock_irqrestore(&ctx->lock, flags);
- }
-
- if (!ctx) {
- ctx = kmalloc(sizeof(struct perf_counter_context), GFP_KERNEL);
- err = -ENOMEM;
- if (!ctx)
- goto errout;
- __perf_counter_init_context(ctx, task);
- get_ctx(ctx);
- if (cmpxchg(&task->perf_counter_ctxp, NULL, ctx)) {
- /*
- * We raced with some other task; use
- * the context they set.
- */
- kfree(ctx);
- goto retry;
- }
- get_task_struct(task);
- }
-
- put_task_struct(task);
- return ctx;
-
- errout:
- put_task_struct(task);
- return ERR_PTR(err);
-}
-
-static void free_counter_rcu(struct rcu_head *head)
-{
- struct perf_counter *counter;
-
- counter = container_of(head, struct perf_counter, rcu_head);
- if (counter->ns)
- put_pid_ns(counter->ns);
- kfree(counter);
-}
-
-static void perf_pending_sync(struct perf_counter *counter);
-
-static void free_counter(struct perf_counter *counter)
-{
- perf_pending_sync(counter);
-
- if (!counter->parent) {
- atomic_dec(&nr_counters);
- if (counter->attr.mmap)
- atomic_dec(&nr_mmap_counters);
- if (counter->attr.comm)
- atomic_dec(&nr_comm_counters);
- if (counter->attr.task)
- atomic_dec(&nr_task_counters);
- }
-
- if (counter->destroy)
- counter->destroy(counter);
-
- put_ctx(counter->ctx);
- call_rcu(&counter->rcu_head, free_counter_rcu);
-}
-
-/*
- * Called when the last reference to the file is gone.
- */
-static int perf_release(struct inode *inode, struct file *file)
-{
- struct perf_counter *counter = file->private_data;
- struct perf_counter_context *ctx = counter->ctx;
-
- file->private_data = NULL;
-
- WARN_ON_ONCE(ctx->parent_ctx);
- mutex_lock(&ctx->mutex);
- perf_counter_remove_from_context(counter);
- mutex_unlock(&ctx->mutex);
-
- mutex_lock(&counter->owner->perf_counter_mutex);
- list_del_init(&counter->owner_entry);
- mutex_unlock(&counter->owner->perf_counter_mutex);
- put_task_struct(counter->owner);
-
- free_counter(counter);
-
- return 0;
-}
-
-static int perf_counter_read_size(struct perf_counter *counter)
-{
- int entry = sizeof(u64); /* value */
- int size = 0;
- int nr = 1;
-
- if (counter->attr.read_format & PERF_FORMAT_TOTAL_TIME_ENABLED)
- size += sizeof(u64);
-
- if (counter->attr.read_format & PERF_FORMAT_TOTAL_TIME_RUNNING)
- size += sizeof(u64);
-
- if (counter->attr.read_format & PERF_FORMAT_ID)
- entry += sizeof(u64);
-
- if (counter->attr.read_format & PERF_FORMAT_GROUP) {
- nr += counter->group_leader->nr_siblings;
- size += sizeof(u64);
- }
-
- size += entry * nr;
-
- return size;
-}
-
-static u64 perf_counter_read_value(struct perf_counter *counter)
-{
- struct perf_counter *child;
- u64 total = 0;
-
- total += perf_counter_read(counter);
- list_for_each_entry(child, &counter->child_list, child_list)
- total += perf_counter_read(child);
-
- return total;
-}
-
-static int perf_counter_read_entry(struct perf_counter *counter,
- u64 read_format, char __user *buf)
-{
- int n = 0, count = 0;
- u64 values[2];
-
- values[n++] = perf_counter_read_value(counter);
- if (read_format & PERF_FORMAT_ID)
- values[n++] = primary_counter_id(counter);
-
- count = n * sizeof(u64);
-
- if (copy_to_user(buf, values, count))
- return -EFAULT;
-
- return count;
-}
-
-static int perf_counter_read_group(struct perf_counter *counter,
- u64 read_format, char __user *buf)
-{
- struct perf_counter *leader = counter->group_leader, *sub;
- int n = 0, size = 0, err = -EFAULT;
- u64 values[3];
-
- values[n++] = 1 + leader->nr_siblings;
- if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED) {
- values[n++] = leader->total_time_enabled +
- atomic64_read(&leader->child_total_time_enabled);
- }
- if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING) {
- values[n++] = leader->total_time_running +
- atomic64_read(&leader->child_total_time_running);
- }
-
- size = n * sizeof(u64);
-
- if (copy_to_user(buf, values, size))
- return -EFAULT;
-
- err = perf_counter_read_entry(leader, read_format, buf + size);
- if (err < 0)
- return err;
-
- size += err;
-
- list_for_each_entry(sub, &leader->sibling_list, list_entry) {
- err = perf_counter_read_entry(sub, read_format,
- buf + size);
- if (err < 0)
- return err;
-
- size += err;
- }
-
- return size;
-}
-
-static int perf_counter_read_one(struct perf_counter *counter,
- u64 read_format, char __user *buf)
-{
- u64 values[4];
- int n = 0;
-
- values[n++] = perf_counter_read_value(counter);
- if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED) {
- values[n++] = counter->total_time_enabled +
- atomic64_read(&counter->child_total_time_enabled);
- }
- if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING) {
- values[n++] = counter->total_time_running +
- atomic64_read(&counter->child_total_time_running);
- }
- if (read_format & PERF_FORMAT_ID)
- values[n++] = primary_counter_id(counter);
-
- if (copy_to_user(buf, values, n * sizeof(u64)))
- return -EFAULT;
-
- return n * sizeof(u64);
-}
-
-/*
- * Read the performance counter - simple non blocking version for now
- */
-static ssize_t
-perf_read_hw(struct perf_counter *counter, char __user *buf, size_t count)
-{
- u64 read_format = counter->attr.read_format;
- int ret;
-
- /*
- * Return end-of-file for a read on a counter 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 (counter->state == PERF_COUNTER_STATE_ERROR)
- return 0;
-
- if (count < perf_counter_read_size(counter))
- return -ENOSPC;
-
- WARN_ON_ONCE(counter->ctx->parent_ctx);
- mutex_lock(&counter->child_mutex);
- if (read_format & PERF_FORMAT_GROUP)
- ret = perf_counter_read_group(counter, read_format, buf);
- else
- ret = perf_counter_read_one(counter, read_format, buf);
- mutex_unlock(&counter->child_mutex);
-
- return ret;
-}
-
-static ssize_t
-perf_read(struct file *file, char __user *buf, size_t count, loff_t *ppos)
-{
- struct perf_counter *counter = file->private_data;
-
- return perf_read_hw(counter, buf, count);
-}
-
-static unsigned int perf_poll(struct file *file, poll_table *wait)
-{
- struct perf_counter *counter = file->private_data;
- struct perf_mmap_data *data;
- unsigned int events = POLL_HUP;
-
- rcu_read_lock();
- data = rcu_dereference(counter->data);
- if (data)
- events = atomic_xchg(&data->poll, 0);
- rcu_read_unlock();
-
- poll_wait(file, &counter->waitq, wait);
-
- return events;
-}
-
-static void perf_counter_reset(struct perf_counter *counter)
-{
- (void)perf_counter_read(counter);
- atomic64_set(&counter->count, 0);
- perf_counter_update_userpage(counter);
-}
-
-/*
- * Holding the top-level counter's child_mutex means that any
- * descendant process that has inherited this counter will block
- * in sync_child_counter if it goes to exit, thus satisfying the
- * task existence requirements of perf_counter_enable/disable.
- */
-static void perf_counter_for_each_child(struct perf_counter *counter,
- void (*func)(struct perf_counter *))
-{
- struct perf_counter *child;
-
- WARN_ON_ONCE(counter->ctx->parent_ctx);
- mutex_lock(&counter->child_mutex);
- func(counter);
- list_for_each_entry(child, &counter->child_list, child_list)
- func(child);
- mutex_unlock(&counter->child_mutex);
-}
-
-static void perf_counter_for_each(struct perf_counter *counter,
- void (*func)(struct perf_counter *))
-{
- struct perf_counter_context *ctx = counter->ctx;
- struct perf_counter *sibling;
-
- WARN_ON_ONCE(ctx->parent_ctx);
- mutex_lock(&ctx->mutex);
- counter = counter->group_leader;
-
- perf_counter_for_each_child(counter, func);
- func(counter);
- list_for_each_entry(sibling, &counter->sibling_list, list_entry)
- perf_counter_for_each_child(counter, func);
- mutex_unlock(&ctx->mutex);
-}
-
-static int perf_counter_period(struct perf_counter *counter, u64 __user *arg)
-{
- struct perf_counter_context *ctx = counter->ctx;
- unsigned long size;
- int ret = 0;
- u64 value;
-
- if (!counter->attr.sample_period)
- return -EINVAL;
-
- size = copy_from_user(&value, arg, sizeof(value));
- if (size != sizeof(value))
- return -EFAULT;
-
- if (!value)
- return -EINVAL;
-
- spin_lock_irq(&ctx->lock);
- if (counter->attr.freq) {
- if (value > sysctl_perf_counter_sample_rate) {
- ret = -EINVAL;
- goto unlock;
- }
-
- counter->attr.sample_freq = value;
- } else {
- counter->attr.sample_period = value;
- counter->hw.sample_period = value;
- }
-unlock:
- spin_unlock_irq(&ctx->lock);
-
- return ret;
-}
-
-static long perf_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
-{
- struct perf_counter *counter = file->private_data;
- void (*func)(struct perf_counter *);
- u32 flags = arg;
-
- switch (cmd) {
- case PERF_COUNTER_IOC_ENABLE:
- func = perf_counter_enable;
- break;
- case PERF_COUNTER_IOC_DISABLE:
- func = perf_counter_disable;
- break;
- case PERF_COUNTER_IOC_RESET:
- func = perf_counter_reset;
- break;
-
- case PERF_COUNTER_IOC_REFRESH:
- return perf_counter_refresh(counter, arg);
-
- case PERF_COUNTER_IOC_PERIOD:
- return perf_counter_period(counter, (u64 __user *)arg);
-
- default:
- return -ENOTTY;
- }
-
- if (flags & PERF_IOC_FLAG_GROUP)
- perf_counter_for_each(counter, func);
- else
- perf_counter_for_each_child(counter, func);
-
- return 0;
-}
-
-int perf_counter_task_enable(void)
-{
- struct perf_counter *counter;
-
- mutex_lock(&current->perf_counter_mutex);
- list_for_each_entry(counter, &current->perf_counter_list, owner_entry)
- perf_counter_for_each_child(counter, perf_counter_enable);
- mutex_unlock(&current->perf_counter_mutex);
-
- return 0;
-}
-
-int perf_counter_task_disable(void)
-{
- struct perf_counter *counter;
-
- mutex_lock(&current->perf_counter_mutex);
- list_for_each_entry(counter, &current->perf_counter_list, owner_entry)
- perf_counter_for_each_child(counter, perf_counter_disable);
- mutex_unlock(&current->perf_counter_mutex);
-
- return 0;
-}
-
-#ifndef PERF_COUNTER_INDEX_OFFSET
-# define PERF_COUNTER_INDEX_OFFSET 0
-#endif
-
-static int perf_counter_index(struct perf_counter *counter)
-{
- if (counter->state != PERF_COUNTER_STATE_ACTIVE)
- return 0;
-
- return counter->hw.idx + 1 - PERF_COUNTER_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_counter_update_userpage(struct perf_counter *counter)
-{
- struct perf_counter_mmap_page *userpg;
- struct perf_mmap_data *data;
-
- rcu_read_lock();
- data = rcu_dereference(counter->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_counter_index(counter);
- userpg->offset = atomic64_read(&counter->count);
- if (counter->state == PERF_COUNTER_STATE_ACTIVE)
- userpg->offset -= atomic64_read(&counter->hw.prev_count);
-
- userpg->time_enabled = counter->total_time_enabled +
- atomic64_read(&counter->child_total_time_enabled);
-
- userpg->time_running = counter->total_time_running +
- atomic64_read(&counter->child_total_time_running);
-
- barrier();
- ++userpg->lock;
- preempt_enable();
-unlock:
- rcu_read_unlock();
-}
-
-static int perf_mmap_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
-{
- struct perf_counter *counter = 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(counter->data);
- if (!data)
- goto unlock;
-
- if (vmf->pgoff == 0) {
- vmf->page = virt_to_page(data->user_page);
- } else {
- int nr = vmf->pgoff - 1;
-
- if ((unsigned)nr > data->nr_pages)
- goto unlock;
-
- if (vmf->flags & FAULT_FLAG_WRITE)
- goto unlock;
-
- vmf->page = virt_to_page(data->data_pages[nr]);
- }
-
- get_page(vmf->page);
- vmf->page->mapping = vma->vm_file->f_mapping;
- vmf->page->index = vmf->pgoff;
-
- ret = 0;
-unlock:
- rcu_read_unlock();
-
- return ret;
-}
-
-static int perf_mmap_data_alloc(struct perf_counter *counter, int nr_pages)
-{
- struct perf_mmap_data *data;
- unsigned long size;
- int i;
-
- WARN_ON(atomic_read(&counter->mmap_count));
-
- size = sizeof(struct perf_mmap_data);
- size += nr_pages * sizeof(void *);
-
- data = kzalloc(size, GFP_KERNEL);
- if (!data)
- goto fail;
-
- data->user_page = (void *)get_zeroed_page(GFP_KERNEL);
- if (!data->user_page)
- goto fail_user_page;
-
- for (i = 0; i < nr_pages; i++) {
- data->data_pages[i] = (void *)get_zeroed_page(GFP_KERNEL);
- if (!data->data_pages[i])
- goto fail_data_pages;
- }
-
- data->nr_pages = nr_pages;
- atomic_set(&data->lock, -1);
-
- rcu_assign_pointer(counter->data, data);
-
- return 0;
-
-fail_data_pages:
- for (i--; i >= 0; i--)
- free_page((unsigned long)data->data_pages[i]);
-
- free_page((unsigned long)data->user_page);
-
-fail_user_page:
- kfree(data);
-
-fail:
- return -ENOMEM;
-}
-
-static void perf_mmap_free_page(unsigned long addr)
-{
- struct page *page = virt_to_page((void *)addr);
-
- page->mapping = NULL;
- __free_page(page);
-}
-
-static void __perf_mmap_data_free(struct rcu_head *rcu_head)
-{
- struct perf_mmap_data *data;
- int i;
-
- data = container_of(rcu_head, struct perf_mmap_data, rcu_head);
-
- perf_mmap_free_page((unsigned long)data->user_page);
- for (i = 0; i < data->nr_pages; i++)
- perf_mmap_free_page((unsigned long)data->data_pages[i]);
-
- kfree(data);
-}
-
-static void perf_mmap_data_free(struct perf_counter *counter)
-{
- struct perf_mmap_data *data = counter->data;
-
- WARN_ON(atomic_read(&counter->mmap_count));
-
- rcu_assign_pointer(counter->data, NULL);
- call_rcu(&data->rcu_head, __perf_mmap_data_free);
-}
-
-static void perf_mmap_open(struct vm_area_struct *vma)
-{
- struct perf_counter *counter = vma->vm_file->private_data;
-
- atomic_inc(&counter->mmap_count);
-}
-
-static void perf_mmap_close(struct vm_area_struct *vma)
-{
- struct perf_counter *counter = vma->vm_file->private_data;
-
- WARN_ON_ONCE(counter->ctx->parent_ctx);
- if (atomic_dec_and_mutex_lock(&counter->mmap_count, &counter->mmap_mutex)) {
- struct user_struct *user = current_user();
-
- atomic_long_sub(counter->data->nr_pages + 1, &user->locked_vm);
- vma->vm_mm->locked_vm -= counter->data->nr_locked;
- perf_mmap_data_free(counter);
- mutex_unlock(&counter->mmap_mutex);
- }
-}
-
-static struct vm_operations_struct perf_mmap_vmops = {
- .open = perf_mmap_open,
- .close = perf_mmap_close,
- .fault = perf_mmap_fault,
- .page_mkwrite = perf_mmap_fault,
-};
-
-static int perf_mmap(struct file *file, struct vm_area_struct *vma)
-{
- struct perf_counter *counter = file->private_data;
- unsigned long user_locked, user_lock_limit;
- struct user_struct *user = current_user();
- unsigned long locked, lock_limit;
- unsigned long vma_size;
- unsigned long nr_pages;
- long user_extra, extra;
- int ret = 0;
-
- if (!(vma->vm_flags & VM_SHARED))
- return -EINVAL;
-
- vma_size = vma->vm_end - vma->vm_start;
- nr_pages = (vma_size / PAGE_SIZE) - 1;
-
- /*
- * If we have data pages ensure they're a power-of-two number, so we
- * can do bitmasks instead of modulo.
- */
- if (nr_pages != 0 && !is_power_of_2(nr_pages))
- return -EINVAL;
-
- if (vma_size != PAGE_SIZE * (1 + nr_pages))
- return -EINVAL;
-
- if (vma->vm_pgoff != 0)
- return -EINVAL;
-
- WARN_ON_ONCE(counter->ctx->parent_ctx);
- mutex_lock(&counter->mmap_mutex);
- if (atomic_inc_not_zero(&counter->mmap_count)) {
- if (nr_pages != counter->data->nr_pages)
- ret = -EINVAL;
- goto unlock;
- }
-
- user_extra = nr_pages + 1;
- user_lock_limit = sysctl_perf_counter_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) && !capable(CAP_IPC_LOCK)) {
- ret = -EPERM;
- goto unlock;
- }
-
- WARN_ON(counter->data);
- ret = perf_mmap_data_alloc(counter, nr_pages);
- if (ret)
- goto unlock;
-
- atomic_set(&counter->mmap_count, 1);
- atomic_long_add(user_extra, &user->locked_vm);
- vma->vm_mm->locked_vm += extra;
- counter->data->nr_locked = extra;
- if (vma->vm_flags & VM_WRITE)
- counter->data->writable = 1;
-
-unlock:
- mutex_unlock(&counter->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_counter *counter = filp->private_data;
- int retval;
-
- mutex_lock(&inode->i_mutex);
- retval = fasync_helper(fd, filp, on, &counter->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 counter wakeup
- *
- * If there's data, ensure we set the poll() state and publish everything
- * to user-space before waking everybody up.
- */
-
-void perf_counter_wakeup(struct perf_counter *counter)
-{
- wake_up_all(&counter->waitq);
-
- if (counter->pending_kill) {
- kill_fasync(&counter->fasync, SIGIO, counter->pending_kill);
- counter->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_counter(struct perf_pending_entry *entry)
-{
- struct perf_counter *counter = container_of(entry,
- struct perf_counter, pending);
-
- if (counter->pending_disable) {
- counter->pending_disable = 0;
- __perf_counter_disable(counter);
- }
-
- if (counter->pending_wakeup) {
- counter->pending_wakeup = 0;
- perf_counter_wakeup(counter);
- }
-}
-
-#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_counter_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_counter *counter)
-{
- /*
- * 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 counter->pending.next == NULL;
-}
-
-static void perf_pending_sync(struct perf_counter *counter)
-{
- wait_event(counter->waitq, perf_not_pending(counter));
-}
-
-void perf_counter_do_pending(void)
-{
- __perf_pending_run();
-}
-
-/*
- * Callchain support -- arch specific
- */
-
-__weak struct perf_callchain_entry *perf_callchain(struct pt_regs *regs)
-{
- return NULL;
-}
-
-/*
- * Output
- */
-
-struct perf_output_handle {
- struct perf_counter *counter;
- struct perf_mmap_data *data;
- unsigned long head;
- unsigned long offset;
- int nmi;
- int sample;
- int locked;
- unsigned long flags;
-};
-
-static bool perf_output_space(struct perf_mmap_data *data,
- unsigned int offset, unsigned int head)
-{
- unsigned long tail;
- unsigned long mask;
-
- if (!data->writable)
- return true;
-
- mask = (data->nr_pages << PAGE_SHIFT) - 1;
- /*
- * 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 = (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->counter->pending_wakeup = 1;
- perf_pending_queue(&handle->counter->pending,
- perf_pending_counter);
- } else
- perf_counter_wakeup(handle->counter);
-}
-
-/*
- * Curious locking construct.
- *
- * We need to ensure a later event doesn't publish a head when a former
- * event isn't done writing. However since we need to deal with NMIs we
- * cannot fully serialize things.
- *
- * 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 completes.
- */
-static void perf_output_lock(struct perf_output_handle *handle)
-{
- struct perf_mmap_data *data = handle->data;
- int cpu;
-
- handle->locked = 0;
-
- local_irq_save(handle->flags);
- cpu = smp_processor_id();
-
- if (in_nmi() && atomic_read(&data->lock) == cpu)
- return;
-
- while (atomic_cmpxchg(&data->lock, -1, cpu) != -1)
- cpu_relax();
-
- handle->locked = 1;
-}
-
-static void perf_output_unlock(struct perf_output_handle *handle)
-{
- struct perf_mmap_data *data = handle->data;
- unsigned long head;
- int cpu;
-
- data->done_head = data->head;
-
- if (!handle->locked)
- goto out;
-
-again:
- /*
- * The xchg implies a full barrier that ensures all writes are done
- * before we publish the new head, matched by a rmb() in userspace when
- * reading this position.
- */
- while ((head = atomic_long_xchg(&data->done_head, 0)))
- data->user_page->data_head = head;
-
- /*
- * NMI can happen here, which means we can miss a done_head update.
- */
-
- cpu = atomic_xchg(&data->lock, -1);
- WARN_ON_ONCE(cpu != smp_processor_id());
-
- /*
- * Therefore we have to validate we did not indeed do so.
- */
- if (unlikely(atomic_long_read(&data->done_head))) {
- /*
- * Since we had it locked, we can lock it again.
- */
- while (atomic_cmpxchg(&data->lock, -1, cpu) != -1)
- cpu_relax();
-
- goto again;
- }
-
- if (atomic_xchg(&data->wakeup, 0))
- perf_output_wakeup(handle);
-out:
- local_irq_restore(handle->flags);
-}
-
-static void perf_output_copy(struct perf_output_handle *handle,
- const void *buf, unsigned int len)
-{
- unsigned int pages_mask;
- unsigned int offset;
- unsigned int size;
- void **pages;
-
- offset = handle->offset;
- pages_mask = handle->data->nr_pages - 1;
- pages = handle->data->data_pages;
-
- do {
- unsigned int page_offset;
- int nr;
-
- nr = (offset >> PAGE_SHIFT) & pages_mask;
- page_offset = offset & (PAGE_SIZE - 1);
- size = min_t(unsigned int, PAGE_SIZE - page_offset, len);
-
- memcpy(pages[nr] + page_offset, buf, size);
-
- len -= size;
- buf += size;
- offset += size;
- } while (len);
-
- handle->offset = offset;
-
- /*
- * Check we didn't copy past our reservation window, taking the
- * possible unsigned int wrap into account.
- */
- WARN_ON_ONCE(((long)(handle->head - handle->offset)) < 0);
-}
-
-#define perf_output_put(handle, x) \
- perf_output_copy((handle), &(x), sizeof(x))
-
-static int perf_output_begin(struct perf_output_handle *handle,
- struct perf_counter *counter, unsigned int size,
- int nmi, int sample)
-{
- struct perf_mmap_data *data;
- unsigned int offset, head;
- int have_lost;
- struct {
- struct perf_event_header header;
- u64 id;
- u64 lost;
- } lost_event;
-
- /*
- * For inherited counters we send all the output towards the parent.
- */
- if (counter->parent)
- counter = counter->parent;
-
- rcu_read_lock();
- data = rcu_dereference(counter->data);
- if (!data)
- goto out;
-
- handle->data = data;
- handle->counter = counter;
- 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 {
- offset = head = atomic_long_read(&data->head);
- head += size;
- if (unlikely(!perf_output_space(data, offset, head)))
- goto fail;
- } while (atomic_long_cmpxchg(&data->head, offset, head) != offset);
-
- handle->offset = offset;
- handle->head = head;
-
- if ((offset >> PAGE_SHIFT) != (head >> PAGE_SHIFT))
- atomic_set(&data->wakeup, 1);
-
- if (have_lost) {
- lost_event.header.type = PERF_EVENT_LOST;
- lost_event.header.misc = 0;
- lost_event.header.size = sizeof(lost_event);
- lost_event.id = counter->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;
-}
-
-static void perf_output_end(struct perf_output_handle *handle)
-{
- struct perf_counter *counter = handle->counter;
- struct perf_mmap_data *data = handle->data;
-
- int wakeup_events = counter->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_counter_pid(struct perf_counter *counter, struct task_struct *p)
-{
- /*
- * only top level counters have the pid namespace they were created in
- */
- if (counter->parent)
- counter = counter->parent;
-
- return task_tgid_nr_ns(p, counter->ns);
-}
-
-static u32 perf_counter_tid(struct perf_counter *counter, struct task_struct *p)
-{
- /*
- * only top level counters have the pid namespace they were created in
- */
- if (counter->parent)
- counter = counter->parent;
-
- return task_pid_nr_ns(p, counter->ns);
-}
-
-static void perf_output_read_one(struct perf_output_handle *handle,
- struct perf_counter *counter)
-{
- u64 read_format = counter->attr.read_format;
- u64 values[4];
- int n = 0;
-
- values[n++] = atomic64_read(&counter->count);
- if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED) {
- values[n++] = counter->total_time_enabled +
- atomic64_read(&counter->child_total_time_enabled);
- }
- if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING) {
- values[n++] = counter->total_time_running +
- atomic64_read(&counter->child_total_time_running);
- }
- if (read_format & PERF_FORMAT_ID)
- values[n++] = primary_counter_id(counter);
-
- perf_output_copy(handle, values, n * sizeof(u64));
-}
-
-/*
- * XXX PERF_FORMAT_GROUP vs inherited counters seems difficult.
- */
-static void perf_output_read_group(struct perf_output_handle *handle,
- struct perf_counter *counter)
-{
- struct perf_counter *leader = counter->group_leader, *sub;
- u64 read_format = counter->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 != counter)
- leader->pmu->read(leader);
-
- values[n++] = atomic64_read(&leader->count);
- if (read_format & PERF_FORMAT_ID)
- values[n++] = primary_counter_id(leader);
-
- perf_output_copy(handle, values, n * sizeof(u64));
-
- list_for_each_entry(sub, &leader->sibling_list, list_entry) {
- n = 0;
-
- if (sub != counter)
- sub->pmu->read(sub);
-
- values[n++] = atomic64_read(&sub->count);
- if (read_format & PERF_FORMAT_ID)
- values[n++] = primary_counter_id(sub);
-
- perf_output_copy(handle, values, n * sizeof(u64));
- }
-}
-
-static void perf_output_read(struct perf_output_handle *handle,
- struct perf_counter *counter)
-{
- if (counter->attr.read_format & PERF_FORMAT_GROUP)
- perf_output_read_group(handle, counter);
- else
- perf_output_read_one(handle, counter);
-}
-
-void perf_counter_output(struct perf_counter *counter, int nmi,
- struct perf_sample_data *data)
-{
- int ret;
- u64 sample_type = counter->attr.sample_type;
- struct perf_output_handle handle;
- struct perf_event_header header;
- u64 ip;
- struct {
- u32 pid, tid;
- } tid_entry;
- struct perf_callchain_entry *callchain = NULL;
- int callchain_size = 0;
- u64 time;
- struct {
- u32 cpu, reserved;
- } cpu_entry;
-
- header.type = PERF_EVENT_SAMPLE;
- header.size = sizeof(header);
-
- header.misc = 0;
- header.misc |= perf_misc_flags(data->regs);
-
- if (sample_type & PERF_SAMPLE_IP) {
- ip = perf_instruction_pointer(data->regs);
- header.size += sizeof(ip);
- }
-
- if (sample_type & PERF_SAMPLE_TID) {
- /* namespace issues */
- tid_entry.pid = perf_counter_pid(counter, current);
- tid_entry.tid = perf_counter_tid(counter, current);
-
- header.size += sizeof(tid_entry);
- }
-
- if (sample_type & PERF_SAMPLE_TIME) {
- /*
- * Maybe do better on x86 and provide cpu_clock_nmi()
- */
- time = sched_clock();
-
- header.size += sizeof(u64);
- }
-
- if (sample_type & PERF_SAMPLE_ADDR)
- header.size += sizeof(u64);
-
- if (sample_type & PERF_SAMPLE_ID)
- header.size += sizeof(u64);
-
- if (sample_type & PERF_SAMPLE_STREAM_ID)
- header.size += sizeof(u64);
-
- if (sample_type & PERF_SAMPLE_CPU) {
- header.size += sizeof(cpu_entry);
-
- cpu_entry.cpu = raw_smp_processor_id();
- cpu_entry.reserved = 0;
- }
-
- if (sample_type & PERF_SAMPLE_PERIOD)
- header.size += sizeof(u64);
-
- if (sample_type & PERF_SAMPLE_READ)
- header.size += perf_counter_read_size(counter);
-
- if (sample_type & PERF_SAMPLE_CALLCHAIN) {
- callchain = perf_callchain(data->regs);
-
- if (callchain) {
- callchain_size = (1 + callchain->nr) * sizeof(u64);
- header.size += callchain_size;
- } else
- header.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;
- }
-
- ret = perf_output_begin(&handle, counter, header.size, nmi, 1);
- if (ret)
- return;
-
- perf_output_put(&handle, header);
-
- if (sample_type & PERF_SAMPLE_IP)
- perf_output_put(&handle, ip);
-
- if (sample_type & PERF_SAMPLE_TID)
- perf_output_put(&handle, tid_entry);
-
- if (sample_type & PERF_SAMPLE_TIME)
- perf_output_put(&handle, time);
-
- if (sample_type & PERF_SAMPLE_ADDR)
- perf_output_put(&handle, data->addr);
-
- if (sample_type & PERF_SAMPLE_ID) {
- u64 id = primary_counter_id(counter);
-
- perf_output_put(&handle, id);
- }
-
- if (sample_type & PERF_SAMPLE_STREAM_ID)
- perf_output_put(&handle, counter->id);
-
- if (sample_type & PERF_SAMPLE_CPU)
- perf_output_put(&handle, cpu_entry);
-
- if (sample_type & PERF_SAMPLE_PERIOD)
- perf_output_put(&handle, data->period);
-
- if (sample_type & PERF_SAMPLE_READ)
- perf_output_read(&handle, counter);
-
- if (sample_type & PERF_SAMPLE_CALLCHAIN) {
- if (callchain)
- perf_output_copy(&handle, callchain, 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);
- }
- }
-
- perf_output_end(&handle);
-}
-
-/*
- * read event
- */
-
-struct perf_read_event {
- struct perf_event_header header;
-
- u32 pid;
- u32 tid;
-};
-
-static void
-perf_counter_read_event(struct perf_counter *counter,
- struct task_struct *task)
-{
- struct perf_output_handle handle;
- struct perf_read_event event = {
- .header = {
- .type = PERF_EVENT_READ,
- .misc = 0,
- .size = sizeof(event) + perf_counter_read_size(counter),
- },
- .pid = perf_counter_pid(counter, task),
- .tid = perf_counter_tid(counter, task),
- };
- int ret;
-
- ret = perf_output_begin(&handle, counter, event.header.size, 0, 0);
- if (ret)
- return;
-
- perf_output_put(&handle, event);
- perf_output_read(&handle, counter);
-
- 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_counter_context *task_ctx;
-
- struct {
- struct perf_event_header header;
-
- u32 pid;
- u32 ppid;
- u32 tid;
- u32 ptid;
- } event;
-};
-
-static void perf_counter_task_output(struct perf_counter *counter,
- struct perf_task_event *task_event)
-{
- struct perf_output_handle handle;
- int size = task_event->event.header.size;
- struct task_struct *task = task_event->task;
- int ret = perf_output_begin(&handle, counter, size, 0, 0);
-
- if (ret)
- return;
-
- task_event->event.pid = perf_counter_pid(counter, task);
- task_event->event.ppid = perf_counter_pid(counter, current);
-
- task_event->event.tid = perf_counter_tid(counter, task);
- task_event->event.ptid = perf_counter_tid(counter, current);
-
- perf_output_put(&handle, task_event->event);
- perf_output_end(&handle);
-}
-
-static int perf_counter_task_match(struct perf_counter *counter)
-{
- if (counter->attr.comm || counter->attr.mmap || counter->attr.task)
- return 1;
-
- return 0;
-}
-
-static void perf_counter_task_ctx(struct perf_counter_context *ctx,
- struct perf_task_event *task_event)
-{
- struct perf_counter *counter;
-
- if (system_state != SYSTEM_RUNNING || list_empty(&ctx->event_list))
- return;
-
- rcu_read_lock();
- list_for_each_entry_rcu(counter, &ctx->event_list, event_entry) {
- if (perf_counter_task_match(counter))
- perf_counter_task_output(counter, task_event);
- }
- rcu_read_unlock();
-}
-
-static void perf_counter_task_event(struct perf_task_event *task_event)
-{
- struct perf_cpu_context *cpuctx;
- struct perf_counter_context *ctx = task_event->task_ctx;
-
- cpuctx = &get_cpu_var(perf_cpu_context);
- perf_counter_task_ctx(&cpuctx->ctx, task_event);
- put_cpu_var(perf_cpu_context);
-
- rcu_read_lock();
- if (!ctx)
- ctx = rcu_dereference(task_event->task->perf_counter_ctxp);
- if (ctx)
- perf_counter_task_ctx(ctx, task_event);
- rcu_read_unlock();
-}
-
-static void perf_counter_task(struct task_struct *task,
- struct perf_counter_context *task_ctx,
- int new)
-{
- struct perf_task_event task_event;
-
- if (!atomic_read(&nr_comm_counters) &&
- !atomic_read(&nr_mmap_counters) &&
- !atomic_read(&nr_task_counters))
- return;
-
- task_event = (struct perf_task_event){
- .task = task,
- .task_ctx = task_ctx,
- .event = {
- .header = {
- .type = new ? PERF_EVENT_FORK : PERF_EVENT_EXIT,
- .misc = 0,
- .size = sizeof(task_event.event),
- },
- /* .pid */
- /* .ppid */
- /* .tid */
- /* .ptid */
- },
- };
-
- perf_counter_task_event(&task_event);
-}
-
-void perf_counter_fork(struct task_struct *task)
-{
- perf_counter_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;
-};
-
-static void perf_counter_comm_output(struct perf_counter *counter,
- struct perf_comm_event *comm_event)
-{
- struct perf_output_handle handle;
- int size = comm_event->event.header.size;
- int ret = perf_output_begin(&handle, counter, size, 0, 0);
-
- if (ret)
- return;
-
- comm_event->event.pid = perf_counter_pid(counter, comm_event->task);
- comm_event->event.tid = perf_counter_tid(counter, comm_event->task);
-
- perf_output_put(&handle, comm_event->event);
- perf_output_copy(&handle, comm_event->comm,
- comm_event->comm_size);
- perf_output_end(&handle);
-}
-
-static int perf_counter_comm_match(struct perf_counter *counter)
-{
- if (counter->attr.comm)
- return 1;
-
- return 0;
-}
-
-static void perf_counter_comm_ctx(struct perf_counter_context *ctx,
- struct perf_comm_event *comm_event)
-{
- struct perf_counter *counter;
-
- if (system_state != SYSTEM_RUNNING || list_empty(&ctx->event_list))
- return;
-
- rcu_read_lock();
- list_for_each_entry_rcu(counter, &ctx->event_list, event_entry) {
- if (perf_counter_comm_match(counter))
- perf_counter_comm_output(counter, comm_event);
- }
- rcu_read_unlock();
-}
-
-static void perf_counter_comm_event(struct perf_comm_event *comm_event)
-{
- struct perf_cpu_context *cpuctx;
- struct perf_counter_context *ctx;
- unsigned int size;
- char comm[TASK_COMM_LEN];
-
- memset(comm, 0, sizeof(comm));
- strncpy(comm, comm_event->task->comm, sizeof(comm));
- size = ALIGN(strlen(comm)+1, sizeof(u64));
-
- comm_event->comm = comm;
- comm_event->comm_size = size;
-
- comm_event->event.header.size = sizeof(comm_event->event) + size;
-
- cpuctx = &get_cpu_var(perf_cpu_context);
- perf_counter_comm_ctx(&cpuctx->ctx, comm_event);
- put_cpu_var(perf_cpu_context);
-
- rcu_read_lock();
- /*
- * doesn't really matter which of the child contexts the
- * events ends up in.
- */
- ctx = rcu_dereference(current->perf_counter_ctxp);
- if (ctx)
- perf_counter_comm_ctx(ctx, comm_event);
- rcu_read_unlock();
-}
-
-void perf_counter_comm(struct task_struct *task)
-{
- struct perf_comm_event comm_event;
-
- if (task->perf_counter_ctxp)
- perf_counter_enable_on_exec(task);
-
- if (!atomic_read(&nr_comm_counters))
- return;
-
- comm_event = (struct perf_comm_event){
- .task = task,
- /* .comm */
- /* .comm_size */
- .event = {
- .header = {
- .type = PERF_EVENT_COMM,
- .misc = 0,
- /* .size */
- },
- /* .pid */
- /* .tid */
- },
- };
-
- perf_counter_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;
-};
-
-static void perf_counter_mmap_output(struct perf_counter *counter,
- struct perf_mmap_event *mmap_event)
-{
- struct perf_output_handle handle;
- int size = mmap_event->event.header.size;
- int ret = perf_output_begin(&handle, counter, size, 0, 0);
-
- if (ret)
- return;
-
- mmap_event->event.pid = perf_counter_pid(counter, current);
- mmap_event->event.tid = perf_counter_tid(counter, current);
-
- perf_output_put(&handle, mmap_event->event);
- perf_output_copy(&handle, mmap_event->file_name,
- mmap_event->file_size);
- perf_output_end(&handle);
-}
-
-static int perf_counter_mmap_match(struct perf_counter *counter,
- struct perf_mmap_event *mmap_event)
-{
- if (counter->attr.mmap)
- return 1;
-
- return 0;
-}
-
-static void perf_counter_mmap_ctx(struct perf_counter_context *ctx,
- struct perf_mmap_event *mmap_event)
-{
- struct perf_counter *counter;
-
- if (system_state != SYSTEM_RUNNING || list_empty(&ctx->event_list))
- return;
-
- rcu_read_lock();
- list_for_each_entry_rcu(counter, &ctx->event_list, event_entry) {
- if (perf_counter_mmap_match(counter, mmap_event))
- perf_counter_mmap_output(counter, mmap_event);
- }
- rcu_read_unlock();
-}
-
-static void perf_counter_mmap_event(struct perf_mmap_event *mmap_event)
-{
- struct perf_cpu_context *cpuctx;
- struct perf_counter_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.header.size = sizeof(mmap_event->event) + size;
-
- cpuctx = &get_cpu_var(perf_cpu_context);
- perf_counter_mmap_ctx(&cpuctx->ctx, mmap_event);
- put_cpu_var(perf_cpu_context);
-
- rcu_read_lock();
- /*
- * doesn't really matter which of the child contexts the
- * events ends up in.
- */
- ctx = rcu_dereference(current->perf_counter_ctxp);
- if (ctx)
- perf_counter_mmap_ctx(ctx, mmap_event);
- rcu_read_unlock();
-
- kfree(buf);
-}
-
-void __perf_counter_mmap(struct vm_area_struct *vma)
-{
- struct perf_mmap_event mmap_event;
-
- if (!atomic_read(&nr_mmap_counters))
- return;
-
- mmap_event = (struct perf_mmap_event){
- .vma = vma,
- /* .file_name */
- /* .file_size */
- .event = {
- .header = {
- .type = PERF_EVENT_MMAP,
- .misc = 0,
- /* .size */
- },
- /* .pid */
- /* .tid */
- .start = vma->vm_start,
- .len = vma->vm_end - vma->vm_start,
- .pgoff = vma->vm_pgoff,
- },
- };
-
- perf_counter_mmap_event(&mmap_event);
-}
-
-/*
- * IRQ throttle logging
- */
-
-static void perf_log_throttle(struct perf_counter *counter, 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_EVENT_THROTTLE,
- .misc = 0,
- .size = sizeof(throttle_event),
- },
- .time = sched_clock(),
- .id = primary_counter_id(counter),
- .stream_id = counter->id,
- };
-
- if (enable)
- throttle_event.header.type = PERF_EVENT_UNTHROTTLE;
-
- ret = perf_output_begin(&handle, counter, sizeof(throttle_event), 1, 0);
- if (ret)
- return;
-
- perf_output_put(&handle, throttle_event);
- perf_output_end(&handle);
-}
-
-/*
- * Generic counter overflow handling, sampling.
- */
-
-int perf_counter_overflow(struct perf_counter *counter, int nmi,
- struct perf_sample_data *data)
-{
- int events = atomic_read(&counter->event_limit);
- int throttle = counter->pmu->unthrottle != NULL;
- struct hw_perf_counter *hwc = &counter->hw;
- int ret = 0;
-
- if (!throttle) {
- hwc->interrupts++;
- } else {
- if (hwc->interrupts != MAX_INTERRUPTS) {
- hwc->interrupts++;
- if (HZ * hwc->interrupts >
- (u64)sysctl_perf_counter_sample_rate) {
- hwc->interrupts = MAX_INTERRUPTS;
- perf_log_throttle(counter, 0);
- ret = 1;
- }
- } else {
- /*
- * Keep re-disabling counters even though on the previous
- * pass we disabled it - just in case we raced with a
- * sched-in and the counter got enabled again:
- */
- ret = 1;
- }
- }
-
- if (counter->attr.freq) {
- u64 now = sched_clock();
- s64 delta = now - hwc->freq_stamp;
-
- hwc->freq_stamp = now;
-
- if (delta > 0 && delta < TICK_NSEC)
- perf_adjust_period(counter, NSEC_PER_SEC / (int)delta);
- }
-
- /*
- * XXX event_limit might not quite work as expected on inherited
- * counters
- */
-
- counter->pending_kill = POLL_IN;
- if (events && atomic_dec_and_test(&counter->event_limit)) {
- ret = 1;
- counter->pending_kill = POLL_HUP;
- if (nmi) {
- counter->pending_disable = 1;
- perf_pending_queue(&counter->pending,
- perf_pending_counter);
- } else
- perf_counter_disable(counter);
- }
-
- perf_counter_output(counter, nmi, data);
- return ret;
-}
-
-/*
- * Generic software counter infrastructure
- */
-
-/*
- * We directly increment counter->count and keep a second value in
- * counter->hw.period_left to count intervals. This period counter
- * is kept in the range [-sample_period, 0] so that we can use the
- * sign as trigger.
- */
-
-static u64 perf_swcounter_set_period(struct perf_counter *counter)
-{
- struct hw_perf_counter *hwc = &counter->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_swcounter_overflow(struct perf_counter *counter,
- int nmi, struct perf_sample_data *data)
-{
- struct hw_perf_counter *hwc = &counter->hw;
- u64 overflow;
-
- data->period = counter->hw.last_period;
- overflow = perf_swcounter_set_period(counter);
-
- if (hwc->interrupts == MAX_INTERRUPTS)
- return;
-
- for (; overflow; overflow--) {
- if (perf_counter_overflow(counter, nmi, data)) {
- /*
- * We inhibit the overflow from happening when
- * hwc->interrupts == MAX_INTERRUPTS.
- */
- break;
- }
- }
-}
-
-static void perf_swcounter_unthrottle(struct perf_counter *counter)
-{
- /*
- * Nothing to do, we already reset hwc->interrupts.
- */
-}
-
-static void perf_swcounter_add(struct perf_counter *counter, u64 nr,
- int nmi, struct perf_sample_data *data)
-{
- struct hw_perf_counter *hwc = &counter->hw;
-
- atomic64_add(nr, &counter->count);
-
- if (!hwc->sample_period)
- return;
-
- if (!data->regs)
- return;
-
- if (!atomic64_add_negative(nr, &hwc->period_left))
- perf_swcounter_overflow(counter, nmi, data);
-}
-
-static int perf_swcounter_is_counting(struct perf_counter *counter)
-{
- /*
- * The counter is active, we're good!
- */
- if (counter->state == PERF_COUNTER_STATE_ACTIVE)
- return 1;
-
- /*
- * The counter is off/error, not counting.
- */
- if (counter->state != PERF_COUNTER_STATE_INACTIVE)
- return 0;
-
- /*
- * The counter is inactive, if the context is active
- * we're part of a group that didn't make it on the 'pmu',
- * not counting.
- */
- if (counter->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_swcounter_match(struct perf_counter *counter,
- enum perf_type_id type,
- u32 event, struct pt_regs *regs)
-{
- if (!perf_swcounter_is_counting(counter))
- return 0;
-
- if (counter->attr.type != type)
- return 0;
- if (counter->attr.config != event)
- return 0;
-
- if (regs) {
- if (counter->attr.exclude_user && user_mode(regs))
- return 0;
-
- if (counter->attr.exclude_kernel && !user_mode(regs))
- return 0;
- }
-
- return 1;
-}
-
-static void perf_swcounter_ctx_event(struct perf_counter_context *ctx,
- enum perf_type_id type,
- u32 event, u64 nr, int nmi,
- struct perf_sample_data *data)
-{
- struct perf_counter *counter;
-
- if (system_state != SYSTEM_RUNNING || list_empty(&ctx->event_list))
- return;
-
- rcu_read_lock();
- list_for_each_entry_rcu(counter, &ctx->event_list, event_entry) {
- if (perf_swcounter_match(counter, type, event, data->regs))
- perf_swcounter_add(counter, nr, nmi, data);
- }
- rcu_read_unlock();
-}
-
-static int *perf_swcounter_recursion_context(struct perf_cpu_context *cpuctx)
-{
- if (in_nmi())
- return &cpuctx->recursion[3];
-
- if (in_irq())
- return &cpuctx->recursion[2];
-
- if (in_softirq())
- return &cpuctx->recursion[1];
-
- return &cpuctx->recursion[0];
-}
-
-static void do_perf_swcounter_event(enum perf_type_id type, u32 event,
- u64 nr, int nmi,
- struct perf_sample_data *data)
-{
- struct perf_cpu_context *cpuctx = &get_cpu_var(perf_cpu_context);
- int *recursion = perf_swcounter_recursion_context(cpuctx);
- struct perf_counter_context *ctx;
-
- if (*recursion)
- goto out;
-
- (*recursion)++;
- barrier();
-
- perf_swcounter_ctx_event(&cpuctx->ctx, type, event,
- nr, nmi, data);
- rcu_read_lock();
- /*
- * doesn't really matter which of the child contexts the
- * events ends up in.
- */
- ctx = rcu_dereference(current->perf_counter_ctxp);
- if (ctx)
- perf_swcounter_ctx_event(ctx, type, event, nr, nmi, data);
- rcu_read_unlock();
-
- barrier();
- (*recursion)--;
-
-out:
- put_cpu_var(perf_cpu_context);
-}
-
-void __perf_swcounter_event(u32 event, u64 nr, int nmi,
- struct pt_regs *regs, u64 addr)
-{
- struct perf_sample_data data = {
- .regs = regs,
- .addr = addr,
- };
-
- do_perf_swcounter_event(PERF_TYPE_SOFTWARE, event, nr, nmi, &data);
-}
-
-static void perf_swcounter_read(struct perf_counter *counter)
-{
-}
-
-static int perf_swcounter_enable(struct perf_counter *counter)
-{
- struct hw_perf_counter *hwc = &counter->hw;
-
- if (hwc->sample_period) {
- hwc->last_period = hwc->sample_period;
- perf_swcounter_set_period(counter);
- }
- return 0;
-}
-
-static void perf_swcounter_disable(struct perf_counter *counter)
-{
-}
-
-static const struct pmu perf_ops_generic = {
- .enable = perf_swcounter_enable,
- .disable = perf_swcounter_disable,
- .read = perf_swcounter_read,
- .unthrottle = perf_swcounter_unthrottle,
-};
-
-/*
- * hrtimer based swcounter callback
- */
-
-static enum hrtimer_restart perf_swcounter_hrtimer(struct hrtimer *hrtimer)
-{
- enum hrtimer_restart ret = HRTIMER_RESTART;
- struct perf_sample_data data;
- struct perf_counter *counter;
- u64 period;
-
- counter = container_of(hrtimer, struct perf_counter, hw.hrtimer);
- counter->pmu->read(counter);
-
- data.addr = 0;
- data.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 ((counter->attr.exclude_kernel || !data.regs) &&
- !counter->attr.exclude_user)
- data.regs = task_pt_regs(current);
-
- if (data.regs) {
- if (perf_counter_overflow(counter, 0, &data))
- ret = HRTIMER_NORESTART;
- }
-
- period = max_t(u64, 10000, counter->hw.sample_period);
- hrtimer_forward_now(hrtimer, ns_to_ktime(period));
-
- return ret;
-}
-
-/*
- * Software counter: cpu wall time clock
- */
-
-static void cpu_clock_perf_counter_update(struct perf_counter *counter)
-{
- int cpu = raw_smp_processor_id();
- s64 prev;
- u64 now;
-
- now = cpu_clock(cpu);
- prev = atomic64_read(&counter->hw.prev_count);
- atomic64_set(&counter->hw.prev_count, now);
- atomic64_add(now - prev, &counter->count);
-}
-
-static int cpu_clock_perf_counter_enable(struct perf_counter *counter)
-{
- struct hw_perf_counter *hwc = &counter->hw;
- int cpu = raw_smp_processor_id();
-
- atomic64_set(&hwc->prev_count, cpu_clock(cpu));
- hrtimer_init(&hwc->hrtimer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
- hwc->hrtimer.function = perf_swcounter_hrtimer;
- if (hwc->sample_period) {
- u64 period = max_t(u64, 10000, hwc->sample_period);
- __hrtimer_start_range_ns(&hwc->hrtimer,
- ns_to_ktime(period), 0,
- HRTIMER_MODE_REL, 0);
- }
-
- return 0;
-}
-
-static void cpu_clock_perf_counter_disable(struct perf_counter *counter)
-{
- if (counter->hw.sample_period)
- hrtimer_cancel(&counter->hw.hrtimer);
- cpu_clock_perf_counter_update(counter);
-}
-
-static void cpu_clock_perf_counter_read(struct perf_counter *counter)
-{
- cpu_clock_perf_counter_update(counter);
-}
-
-static const struct pmu perf_ops_cpu_clock = {
- .enable = cpu_clock_perf_counter_enable,
- .disable = cpu_clock_perf_counter_disable,
- .read = cpu_clock_perf_counter_read,
-};
-
-/*
- * Software counter: task time clock
- */
-
-static void task_clock_perf_counter_update(struct perf_counter *counter, u64 now)
-{
- u64 prev;
- s64 delta;
-
- prev = atomic64_xchg(&counter->hw.prev_count, now);
- delta = now - prev;
- atomic64_add(delta, &counter->count);
-}
-
-static int task_clock_perf_counter_enable(struct perf_counter *counter)
-{
- struct hw_perf_counter *hwc = &counter->hw;
- u64 now;
-
- now = counter->ctx->time;
-
- atomic64_set(&hwc->prev_count, now);
- hrtimer_init(&hwc->hrtimer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
- hwc->hrtimer.function = perf_swcounter_hrtimer;
- if (hwc->sample_period) {
- u64 period = max_t(u64, 10000, hwc->sample_period);
- __hrtimer_start_range_ns(&hwc->hrtimer,
- ns_to_ktime(period), 0,
- HRTIMER_MODE_REL, 0);
- }
-
- return 0;
-}
-
-static void task_clock_perf_counter_disable(struct perf_counter *counter)
-{
- if (counter->hw.sample_period)
- hrtimer_cancel(&counter->hw.hrtimer);
- task_clock_perf_counter_update(counter, counter->ctx->time);
-
-}
-
-static void task_clock_perf_counter_read(struct perf_counter *counter)
-{
- u64 time;
-
- if (!in_nmi()) {
- update_context_time(counter->ctx);
- time = counter->ctx->time;
- } else {
- u64 now = perf_clock();
- u64 delta = now - counter->ctx->timestamp;
- time = counter->ctx->time + delta;
- }
-
- task_clock_perf_counter_update(counter, time);
-}
-
-static const struct pmu perf_ops_task_clock = {
- .enable = task_clock_perf_counter_enable,
- .disable = task_clock_perf_counter_disable,
- .read = task_clock_perf_counter_read,
-};
-
-#ifdef CONFIG_EVENT_PROFILE
-void perf_tpcounter_event(int event_id, u64 addr, u64 count, void *record,
- int entry_size)
-{
- struct perf_raw_record raw = {
- .size = entry_size,
- .data = record,
- };
-
- struct perf_sample_data data = {
- .regs = get_irq_regs(),
- .addr = addr,
- .raw = &raw,
- };
-
- if (!data.regs)
- data.regs = task_pt_regs(current);
-
- do_perf_swcounter_event(PERF_TYPE_TRACEPOINT, event_id, count, 1, &data);
-}
-EXPORT_SYMBOL_GPL(perf_tpcounter_event);
-
-extern int ftrace_profile_enable(int);
-extern void ftrace_profile_disable(int);
-
-static void tp_perf_counter_destroy(struct perf_counter *counter)
-{
- ftrace_profile_disable(counter->attr.config);
-}
-
-static const struct pmu *tp_perf_counter_init(struct perf_counter *counter)
-{
- /*
- * Raw tracepoint data is a severe data leak, only allow root to
- * have these.
- */
- if ((counter->attr.sample_type & PERF_SAMPLE_RAW) &&
- !capable(CAP_SYS_ADMIN))
- return ERR_PTR(-EPERM);
-
- if (ftrace_profile_enable(counter->attr.config))
- return NULL;
-
- counter->destroy = tp_perf_counter_destroy;
-
- return &perf_ops_generic;
-}
-#else
-static const struct pmu *tp_perf_counter_init(struct perf_counter *counter)
-{
- return NULL;
-}
-#endif
-
-atomic_t perf_swcounter_enabled[PERF_COUNT_SW_MAX];
-
-static void sw_perf_counter_destroy(struct perf_counter *counter)
-{
- u64 event = counter->attr.config;
-
- WARN_ON(counter->parent);
-
- atomic_dec(&perf_swcounter_enabled[event]);
-}
-
-static const struct pmu *sw_perf_counter_init(struct perf_counter *counter)
-{
- const struct pmu *pmu = NULL;
- u64 event = counter->attr.config;
-
- /*
- * Software counters (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) {
- 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 counter,
- * use the cpu_clock counter instead.
- */
- if (counter->ctx->task)
- pmu = &perf_ops_task_clock;
- else
- pmu = &perf_ops_cpu_clock;
-
- break;
- case PERF_COUNT_SW_PAGE_FAULTS:
- case PERF_COUNT_SW_PAGE_FAULTS_MIN:
- case PERF_COUNT_SW_PAGE_FAULTS_MAJ:
- case PERF_COUNT_SW_CONTEXT_SWITCHES:
- case PERF_COUNT_SW_CPU_MIGRATIONS:
- if (!counter->parent) {
- atomic_inc(&perf_swcounter_enabled[event]);
- counter->destroy = sw_perf_counter_destroy;
- }
- pmu = &perf_ops_generic;
- break;
- }
-
- return pmu;
-}
-
-/*
- * Allocate and initialize a counter structure
- */
-static struct perf_counter *
-perf_counter_alloc(struct perf_counter_attr *attr,
- int cpu,
- struct perf_counter_context *ctx,
- struct perf_counter *group_leader,
- struct perf_counter *parent_counter,
- gfp_t gfpflags)
-{
- const struct pmu *pmu;
- struct perf_counter *counter;
- struct hw_perf_counter *hwc;
- long err;
-
- counter = kzalloc(sizeof(*counter), gfpflags);
- if (!counter)
- return ERR_PTR(-ENOMEM);
-
- /*
- * Single counters are their own group leaders, with an
- * empty sibling list:
- */
- if (!group_leader)
- group_leader = counter;
-
- mutex_init(&counter->child_mutex);
- INIT_LIST_HEAD(&counter->child_list);
-
- INIT_LIST_HEAD(&counter->list_entry);
- INIT_LIST_HEAD(&counter->event_entry);
- INIT_LIST_HEAD(&counter->sibling_list);
- init_waitqueue_head(&counter->waitq);
-
- mutex_init(&counter->mmap_mutex);
-
- counter->cpu = cpu;
- counter->attr = *attr;
- counter->group_leader = group_leader;
- counter->pmu = NULL;
- counter->ctx = ctx;
- counter->oncpu = -1;
-
- counter->parent = parent_counter;
-
- counter->ns = get_pid_ns(current->nsproxy->pid_ns);
- counter->id = atomic64_inc_return(&perf_counter_id);
-
- counter->state = PERF_COUNTER_STATE_INACTIVE;
-
- if (attr->disabled)
- counter->state = PERF_COUNTER_STATE_OFF;
-
- pmu = NULL;
-
- hwc = &counter->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 counters
- */
- 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_counter_init(counter);
- break;
-
- case PERF_TYPE_SOFTWARE:
- pmu = sw_perf_counter_init(counter);
- break;
-
- case PERF_TYPE_TRACEPOINT:
- pmu = tp_perf_counter_init(counter);
- break;
-
- default:
- break;
- }
-done:
- err = 0;
- if (!pmu)
- err = -EINVAL;
- else if (IS_ERR(pmu))
- err = PTR_ERR(pmu);
-
- if (err) {
- if (counter->ns)
- put_pid_ns(counter->ns);
- kfree(counter);
- return ERR_PTR(err);
- }
-
- counter->pmu = pmu;
-
- if (!counter->parent) {
- atomic_inc(&nr_counters);
- if (counter->attr.mmap)
- atomic_inc(&nr_mmap_counters);
- if (counter->attr.comm)
- atomic_inc(&nr_comm_counters);
- if (counter->attr.task)
- atomic_inc(&nr_task_counters);
- }
-
- return counter;
-}
-
-static int perf_copy_attr(struct perf_counter_attr __user *uattr,
- struct perf_counter_attr *attr)
-{
- int ret;
- u32 size;
-
- 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.
- */
- if (size > sizeof(*attr)) {
- unsigned long val;
- unsigned long __user *addr;
- unsigned long __user *end;
-
- addr = PTR_ALIGN((void __user *)uattr + sizeof(*attr),
- sizeof(unsigned long));
- end = PTR_ALIGN((void __user *)uattr + size,
- sizeof(unsigned long));
-
- for (; addr < end; addr += sizeof(unsigned long)) {
- ret = get_user(val, addr);
- if (ret)
- return ret;
- if (val)
- goto err_size;
- }
- }
-
- ret = copy_from_user(attr, uattr, size);
- if (ret)
- return -EFAULT;
-
- /*
- * If the type exists, the corresponding creation will verify
- * the attr->config.
- */
- if (attr->type >= PERF_TYPE_MAX)
- return -EINVAL;
-
- if (attr->__reserved_1 || attr->__reserved_2 || attr->__reserved_3)
- return -EINVAL;
-
- if (attr->sample_type & ~(PERF_SAMPLE_MAX-1))
- return -EINVAL;
-
- if (attr->read_format & ~(PERF_FORMAT_MAX-1))
- return -EINVAL;
-
-out:
- return ret;
-
-err_size:
- put_user(sizeof(*attr), &uattr->size);
- ret = -E2BIG;
- goto out;
-}
-
-/**
- * sys_perf_counter_open - open a performance counter, associate it to a task/cpu
- *
- * @attr_uptr: event type attributes for monitoring/sampling
- * @pid: target pid
- * @cpu: target cpu
- * @group_fd: group leader counter fd
- */
-SYSCALL_DEFINE5(perf_counter_open,
- struct perf_counter_attr __user *, attr_uptr,
- pid_t, pid, int, cpu, int, group_fd, unsigned long, flags)
-{
- struct perf_counter *counter, *group_leader;
- struct perf_counter_attr attr;
- struct perf_counter_context *ctx;
- struct file *counter_file = NULL;
- struct file *group_file = NULL;
- int fput_needed = 0;
- int fput_needed2 = 0;
- int ret;
-
- /* for future expandability... */
- if (flags)
- return -EINVAL;
-
- ret = perf_copy_attr(attr_uptr, &attr);
- if (ret)
- return ret;
-
- if (!attr.exclude_kernel) {
- if (perf_paranoid_kernel() && !capable(CAP_SYS_ADMIN))
- return -EACCES;
- }
-
- if (attr.freq) {
- if (attr.sample_freq > sysctl_perf_counter_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 counter to it):
- */
- group_leader = NULL;
- if (group_fd != -1) {
- ret = -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;
- }
-
- counter = perf_counter_alloc(&attr, cpu, ctx, group_leader,
- NULL, GFP_KERNEL);
- ret = PTR_ERR(counter);
- if (IS_ERR(counter))
- goto err_put_context;
-
- ret = anon_inode_getfd("[perf_counter]", &perf_fops, counter, 0);
- if (ret < 0)
- goto err_free_put_context;
-
- counter_file = fget_light(ret, &fput_needed2);
- if (!counter_file)
- goto err_free_put_context;
-
- counter->filp = counter_file;
- WARN_ON_ONCE(ctx->parent_ctx);
- mutex_lock(&ctx->mutex);
- perf_install_in_context(ctx, counter, cpu);
- ++ctx->generation;
- mutex_unlock(&ctx->mutex);
-
- counter->owner = current;
- get_task_struct(current);
- mutex_lock(&current->perf_counter_mutex);
- list_add_tail(&counter->owner_entry, &current->perf_counter_list);
- mutex_unlock(&current->perf_counter_mutex);
-
- fput_light(counter_file, fput_needed2);
-
-out_fput:
- fput_light(group_file, fput_needed);
-
- return ret;
-
-err_free_put_context:
- kfree(counter);
-
-err_put_context:
- put_ctx(ctx);
-
- goto out_fput;
-}
-
-/*
- * inherit a counter from parent task to child task:
- */
-static struct perf_counter *
-inherit_counter(struct perf_counter *parent_counter,
- struct task_struct *parent,
- struct perf_counter_context *parent_ctx,
- struct task_struct *child,
- struct perf_counter *group_leader,
- struct perf_counter_context *child_ctx)
-{
- struct perf_counter *child_counter;
-
- /*
- * Instead of creating recursive hierarchies of counters,
- * we link inherited counters back to the original parent,
- * which has a filp for sure, which we use as the reference
- * count:
- */
- if (parent_counter->parent)
- parent_counter = parent_counter->parent;
-
- child_counter = perf_counter_alloc(&parent_counter->attr,
- parent_counter->cpu, child_ctx,
- group_leader, parent_counter,
- GFP_KERNEL);
- if (IS_ERR(child_counter))
- return child_counter;
- get_ctx(child_ctx);
-
- /*
- * Make the child state follow the state of the parent counter,
- * not its attr.disabled bit. We hold the parent's mutex,
- * so we won't race with perf_counter_{en, dis}able_family.
- */
- if (parent_counter->state >= PERF_COUNTER_STATE_INACTIVE)
- child_counter->state = PERF_COUNTER_STATE_INACTIVE;
- else
- child_counter->state = PERF_COUNTER_STATE_OFF;
-
- if (parent_counter->attr.freq)
- child_counter->hw.sample_period = parent_counter->hw.sample_period;
-
- /*
- * Link it up in the child's context:
- */
- add_counter_to_ctx(child_counter, child_ctx);
-
- /*
- * Get a reference to the parent filp - we will fput it
- * when the child counter 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_counter->filp->f_count);
-
- /*
- * Link this into the parent counter's child list
- */
- WARN_ON_ONCE(parent_counter->ctx->parent_ctx);
- mutex_lock(&parent_counter->child_mutex);
- list_add_tail(&child_counter->child_list, &parent_counter->child_list);
- mutex_unlock(&parent_counter->child_mutex);
-
- return child_counter;
-}
-
-static int inherit_group(struct perf_counter *parent_counter,
- struct task_struct *parent,
- struct perf_counter_context *parent_ctx,
- struct task_struct *child,
- struct perf_counter_context *child_ctx)
-{
- struct perf_counter *leader;
- struct perf_counter *sub;
- struct perf_counter *child_ctr;
-
- leader = inherit_counter(parent_counter, parent, parent_ctx,
- child, NULL, child_ctx);
- if (IS_ERR(leader))
- return PTR_ERR(leader);
- list_for_each_entry(sub, &parent_counter->sibling_list, list_entry) {
- child_ctr = inherit_counter(sub, parent, parent_ctx,
- child, leader, child_ctx);
- if (IS_ERR(child_ctr))
- return PTR_ERR(child_ctr);
- }
- return 0;
-}
-
-static void sync_child_counter(struct perf_counter *child_counter,
- struct task_struct *child)
-{
- struct perf_counter *parent_counter = child_counter->parent;
- u64 child_val;
-
- if (child_counter->attr.inherit_stat)
- perf_counter_read_event(child_counter, child);
-
- child_val = atomic64_read(&child_counter->count);
-
- /*
- * Add back the child's count to the parent's count:
- */
- atomic64_add(child_val, &parent_counter->count);
- atomic64_add(child_counter->total_time_enabled,
- &parent_counter->child_total_time_enabled);
- atomic64_add(child_counter->total_time_running,
- &parent_counter->child_total_time_running);
-
- /*
- * Remove this counter from the parent's list
- */
- WARN_ON_ONCE(parent_counter->ctx->parent_ctx);
- mutex_lock(&parent_counter->child_mutex);
- list_del_init(&child_counter->child_list);
- mutex_unlock(&parent_counter->child_mutex);
-
- /*
- * Release the parent counter, if this was the last
- * reference to it.
- */
- fput(parent_counter->filp);
-}
-
-static void
-__perf_counter_exit_task(struct perf_counter *child_counter,
- struct perf_counter_context *child_ctx,
- struct task_struct *child)
-{
- struct perf_counter *parent_counter;
-
- update_counter_times(child_counter);
- perf_counter_remove_from_context(child_counter);
-
- parent_counter = child_counter->parent;
- /*
- * It can happen that parent exits first, and has counters
- * that are still around due to the child reference. These
- * counters need to be zapped - but otherwise linger.
- */
- if (parent_counter) {
- sync_child_counter(child_counter, child);
- free_counter(child_counter);
- }
-}
-
-/*
- * When a child task exits, feed back counter values to parent counters.
- */
-void perf_counter_exit_task(struct task_struct *child)
-{
- struct perf_counter *child_counter, *tmp;
- struct perf_counter_context *child_ctx;
- unsigned long flags;
-
- if (likely(!child->perf_counter_ctxp)) {
- perf_counter_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_counter_ctxp;
- __perf_counter_task_sched_out(child_ctx);
-
- /*
- * Take the context lock here so that if find_get_context is
- * reading child->perf_counter_ctxp, we wait until it has
- * incremented the context's refcount before we do put_ctx below.
- */
- spin_lock(&child_ctx->lock);
- child->perf_counter_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 counters from it.
- */
- unclone_ctx(child_ctx);
- spin_unlock_irqrestore(&child_ctx->lock, flags);
-
- /*
- * Report the task dead after unscheduling the counters so that we
- * won't get any samples after PERF_EVENT_EXIT. We can however still
- * get a few PERF_EVENT_READ events.
- */
- perf_counter_task(child, child_ctx, 0);
-
- /*
- * We can recurse on the same lock type through:
- *
- * __perf_counter_exit_task()
- * sync_child_counter()
- * fput(parent_counter->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_counter, tmp, &child_ctx->counter_list,
- list_entry)
- __perf_counter_exit_task(child_counter, child_ctx, child);
-
- /*
- * If the last counter was a group counter, 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->counter_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_counter_free_task(struct task_struct *task)
-{
- struct perf_counter_context *ctx = task->perf_counter_ctxp;
- struct perf_counter *counter, *tmp;
-
- if (!ctx)
- return;
-
- mutex_lock(&ctx->mutex);
-again:
- list_for_each_entry_safe(counter, tmp, &ctx->counter_list, list_entry) {
- struct perf_counter *parent = counter->parent;
-
- if (WARN_ON_ONCE(!parent))
- continue;
-
- mutex_lock(&parent->child_mutex);
- list_del_init(&counter->child_list);
- mutex_unlock(&parent->child_mutex);
-
- fput(parent->filp);
-
- list_del_counter(counter, ctx);
- free_counter(counter);
- }
-
- if (!list_empty(&ctx->counter_list))
- goto again;
-
- mutex_unlock(&ctx->mutex);
-
- put_ctx(ctx);
-}
-
-/*
- * Initialize the perf_counter context in task_struct
- */
-int perf_counter_init_task(struct task_struct *child)
-{
- struct perf_counter_context *child_ctx, *parent_ctx;
- struct perf_counter_context *cloned_ctx;
- struct perf_counter *counter;
- struct task_struct *parent = current;
- int inherited_all = 1;
- int ret = 0;
-
- child->perf_counter_ctxp = NULL;
-
- mutex_init(&child->perf_counter_mutex);
- INIT_LIST_HEAD(&child->perf_counter_list);
-
- if (likely(!parent->perf_counter_ctxp))
- return 0;
-
- /*
- * This is executed from the parent task context, so inherit
- * counters that have been marked for cloning.
- * First allocate and initialize a context for the child.
- */
-
- child_ctx = kmalloc(sizeof(struct perf_counter_context), GFP_KERNEL);
- if (!child_ctx)
- return -ENOMEM;
-
- __perf_counter_init_context(child_ctx, child);
- child->perf_counter_ctxp = child_ctx;
- get_task_struct(child);
-
- /*
- * If the parent's context is a clone, pin it so it won't get
- * swapped under us.
- */
- parent_ctx = perf_pin_task_context(parent);
-
- /*
- * No need to check if parent_ctx != NULL here; since we saw
- * it non-NULL earlier, the only reason for it to become NULL
- * is if we exit, and since we're currently in the middle of
- * a fork we can't be exiting at the same time.
- */
-
- /*
- * Lock the parent list. No need to lock the child - not PID
- * hashed yet and not running, so nobody can access it.
- */
- mutex_lock(&parent_ctx->mutex);
-
- /*
- * We dont have to disable NMIs - we are only looking at
- * the list, not manipulating it:
- */
- list_for_each_entry_rcu(counter, &parent_ctx->event_list, event_entry) {
- if (counter != counter->group_leader)
- continue;
-
- if (!counter->attr.inherit) {
- inherited_all = 0;
- continue;
- }
-
- ret = inherit_group(counter, parent, parent_ctx,
- child, child_ctx);
- if (ret) {
- inherited_all = 0;
- break;
- }
- }
-
- if (inherited_all) {
- /*
- * Mark the child context as a clone of the parent
- * context, or of whatever the parent is a clone of.
- * Note that if the parent is a clone, it could get
- * uncloned at any point, but that doesn't matter
- * because the list of counters and the generation
- * count can't have changed since we took the mutex.
- */
- cloned_ctx = rcu_dereference(parent_ctx->parent_ctx);
- if (cloned_ctx) {
- child_ctx->parent_ctx = cloned_ctx;
- child_ctx->parent_gen = parent_ctx->parent_gen;
- } else {
- child_ctx->parent_ctx = parent_ctx;
- child_ctx->parent_gen = parent_ctx->generation;
- }
- get_ctx(child_ctx->parent_ctx);
- }
-
- mutex_unlock(&parent_ctx->mutex);
-
- perf_unpin_context(parent_ctx);
-
- return ret;
-}
-
-static void __cpuinit perf_counter_init_cpu(int cpu)
-{
- struct perf_cpu_context *cpuctx;
-
- cpuctx = &per_cpu(perf_cpu_context, cpu);
- __perf_counter_init_context(&cpuctx->ctx, NULL);
-
- spin_lock(&perf_resource_lock);
- cpuctx->max_pertask = perf_max_counters - perf_reserved_percpu;
- spin_unlock(&perf_resource_lock);
-
- hw_perf_counter_setup(cpu);
-}
-
-#ifdef CONFIG_HOTPLUG_CPU
-static void __perf_counter_exit_cpu(void *info)
-{
- struct perf_cpu_context *cpuctx = &__get_cpu_var(perf_cpu_context);
- struct perf_counter_context *ctx = &cpuctx->ctx;
- struct perf_counter *counter, *tmp;
-
- list_for_each_entry_safe(counter, tmp, &ctx->counter_list, list_entry)
- __perf_counter_remove_from_context(counter);
-}
-static void perf_counter_exit_cpu(int cpu)
-{
- struct perf_cpu_context *cpuctx = &per_cpu(perf_cpu_context, cpu);
- struct perf_counter_context *ctx = &cpuctx->ctx;
-
- mutex_lock(&ctx->mutex);
- smp_call_function_single(cpu, __perf_counter_exit_cpu, NULL, 1);
- mutex_unlock(&ctx->mutex);
-}
-#else
-static inline void perf_counter_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_counter_init_cpu(cpu);
- break;
-
- case CPU_ONLINE:
- case CPU_ONLINE_FROZEN:
- hw_perf_counter_setup_online(cpu);
- break;
-
- case CPU_DOWN_PREPARE:
- case CPU_DOWN_PREPARE_FROZEN:
- perf_counter_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_counter_init(void)
-{
- perf_cpu_notify(&perf_cpu_nb, (unsigned long)CPU_UP_PREPARE,
- (void *)(long)smp_processor_id());
- perf_cpu_notify(&perf_cpu_nb, (unsigned long)CPU_ONLINE,
- (void *)(long)smp_processor_id());
- register_cpu_notifier(&perf_cpu_nb);
-}
-
-static ssize_t perf_show_reserve_percpu(struct sysdev_class *class, char *buf)
-{
- return sprintf(buf, "%d\n", perf_reserved_percpu);
-}
-
-static ssize_t
-perf_set_reserve_percpu(struct sysdev_class *class,
- const char *buf,
- size_t count)
-{
- struct perf_cpu_context *cpuctx;
- unsigned long val;
- int err, cpu, mpt;
-
- err = strict_strtoul(buf, 10, &val);
- if (err)
- return err;
- if (val > perf_max_counters)
- return -EINVAL;
-
- spin_lock(&perf_resource_lock);
- perf_reserved_percpu = val;
- for_each_online_cpu(cpu) {
- cpuctx = &per_cpu(perf_cpu_context, cpu);
- spin_lock_irq(&cpuctx->ctx.lock);
- mpt = min(perf_max_counters - cpuctx->ctx.nr_counters,
- perf_max_counters - perf_reserved_percpu);
- cpuctx->max_pertask = mpt;
- spin_unlock_irq(&cpuctx->ctx.lock);
- }
- spin_unlock(&perf_resource_lock);
-
- return count;
-}
-
-static ssize_t perf_show_overcommit(struct sysdev_class *class, char *buf)
-{
- return sprintf(buf, "%d\n", perf_overcommit);
-}
-
-static ssize_t
-perf_set_overcommit(struct sysdev_class *class, const char *buf, size_t count)
-{
- unsigned long val;
- int err;
-
- err = strict_strtoul(buf, 10, &val);
- if (err)
- return err;
- if (val > 1)
- return -EINVAL;
-
- spin_lock(&perf_resource_lock);
- perf_overcommit = val;
- spin_unlock(&perf_resource_lock);
-
- return count;
-}
-
-static SYSDEV_CLASS_ATTR(
- reserve_percpu,
- 0644,
- perf_show_reserve_percpu,
- perf_set_reserve_percpu
- );
-
-static SYSDEV_CLASS_ATTR(
- overcommit,
- 0644,
- perf_show_overcommit,
- perf_set_overcommit
- );
-
-static struct attribute *perfclass_attrs[] = {
- &attr_reserve_percpu.attr,
- &attr_overcommit.attr,
- NULL
-};
-
-static struct attribute_group perfclass_attr_group = {
- .attrs = perfclass_attrs,
- .name = "perf_counters",
-};
-
-static int __init perf_counter_sysfs_init(void)
-{
- return sysfs_create_group(&cpu_sysdev_class.kset.kobj,
- &perfclass_attr_group);
-}
-device_initcall(perf_counter_sysfs_init);