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- /*
- * Performance counter core code
- *
- * Copyright(C) 2008 Thomas Gleixner <tglx@linutronix.de>
- * Copyright(C) 2008 Red Hat, Inc., Ingo Molnar
- *
- *
- * 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/ptrace.h>
- #include <linux/percpu.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 <linux/dcache.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_mmap_tracking __read_mostly;
- static atomic_t nr_munmap_tracking __read_mostly;
- static atomic_t nr_comm_tracking __read_mostly;
- int sysctl_perf_counter_priv __read_mostly; /* do we need to be privileged */
- /*
- * Mutex for (sysadmin-configurable) counter reservations:
- */
- static DEFINE_MUTEX(perf_resource_mutex);
- /*
- * Architecture provided APIs - weak aliases:
- */
- extern __weak const struct hw_perf_counter_ops *
- hw_perf_counter_init(struct perf_counter *counter)
- {
- return NULL;
- }
- u64 __weak hw_perf_save_disable(void) { return 0; }
- void __weak hw_perf_restore(u64 ctrl) { barrier(); }
- void __weak hw_perf_counter_setup(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 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 (counter->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);
- }
- static void
- list_del_counter(struct perf_counter *counter, struct perf_counter_context *ctx)
- {
- struct perf_counter *sibling, *tmp;
- 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;
- counter->tstamp_stopped = ctx->time;
- counter->hw_ops->disable(counter);
- counter->oncpu = -1;
- if (!is_software_counter(counter))
- cpuctx->active_oncpu--;
- ctx->nr_active--;
- if (counter->hw_event.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->hw_event.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;
- unsigned long flags;
- u64 perf_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.
- */
- if (ctx->task && cpuctx->task_ctx != ctx)
- return;
- spin_lock_irqsave(&ctx->lock, flags);
- counter_sched_out(counter, cpuctx, ctx);
- counter->task = NULL;
- ctx->nr_counters--;
- /*
- * Protect the list operation against NMI by disabling the
- * counters on a global level. NOP for non NMI based counters.
- */
- perf_flags = hw_perf_save_disable();
- list_del_counter(counter, ctx);
- hw_perf_restore(perf_flags);
- 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);
- }
- spin_unlock_irqrestore(&ctx->lock, flags);
- }
- /*
- * Remove the counter from a task's (or a CPU's) list of counters.
- *
- * Must be called with counter->mutex and ctx->mutex held.
- *
- * CPU counters are removed with a smp call. For task counters we only
- * call when the task is on a CPU.
- */
- 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)) {
- ctx->nr_counters--;
- list_del_counter(counter, ctx);
- counter->task = NULL;
- }
- 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;
- unsigned long flags;
- /*
- * 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_irqsave(&ctx->lock, flags);
- /*
- * 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_irqrestore(&ctx->lock, flags);
- }
- /*
- * Disable a counter.
- */
- 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);
- }
- /*
- * Disable a counter and all its children.
- */
- static void perf_counter_disable_family(struct perf_counter *counter)
- {
- struct perf_counter *child;
- perf_counter_disable(counter);
- /*
- * Lock the mutex to protect the list of children
- */
- mutex_lock(&counter->mutex);
- list_for_each_entry(child, &counter->child_list, child_list)
- perf_counter_disable(child);
- mutex_unlock(&counter->mutex);
- }
- 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->hw_ops->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->hw_event.exclusive)
- cpuctx->exclusive = 1;
- return 0;
- }
- /*
- * 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->hw_event.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);
- ctx->nr_counters++;
- counter->prev_state = PERF_COUNTER_STATE_OFF;
- 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
- */
- 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();
- unsigned long flags;
- u64 perf_flags;
- 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.
- */
- if (ctx->task && cpuctx->task_ctx != ctx)
- return;
- spin_lock_irqsave(&ctx->lock, flags);
- 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_flags = hw_perf_save_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->hw_event.pinned) {
- update_group_times(leader);
- leader->state = PERF_COUNTER_STATE_ERROR;
- }
- }
- if (!err && !ctx->task && cpuctx->max_pertask)
- cpuctx->max_pertask--;
- unlock:
- hw_perf_restore(perf_flags);
- spin_unlock_irqrestore(&ctx->lock, flags);
- }
- /*
- * 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;
- }
- counter->task = task;
- 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;
- unsigned long flags;
- 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)
- return;
- spin_lock_irqsave(&ctx->lock, flags);
- update_context_time(ctx);
- counter->prev_state = counter->state;
- 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
- err = counter_sched_in(counter, cpuctx, ctx,
- smp_processor_id());
- 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->hw_event.pinned) {
- update_group_times(leader);
- leader->state = PERF_COUNTER_STATE_ERROR;
- }
- }
- unlock:
- spin_unlock_irqrestore(&ctx->lock, flags);
- }
- /*
- * Enable a counter.
- */
- 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 void perf_counter_refresh(struct perf_counter *counter, int refresh)
- {
- atomic_add(refresh, &counter->event_limit);
- perf_counter_enable(counter);
- }
- /*
- * Enable a counter and all its children.
- */
- static void perf_counter_enable_family(struct perf_counter *counter)
- {
- struct perf_counter *child;
- perf_counter_enable(counter);
- /*
- * Lock the mutex to protect the list of children
- */
- mutex_lock(&counter->mutex);
- list_for_each_entry(child, &counter->child_list, child_list)
- perf_counter_enable(child);
- mutex_unlock(&counter->mutex);
- }
- void __perf_counter_sched_out(struct perf_counter_context *ctx,
- struct perf_cpu_context *cpuctx)
- {
- struct perf_counter *counter;
- u64 flags;
- spin_lock(&ctx->lock);
- ctx->is_active = 0;
- if (likely(!ctx->nr_counters))
- goto out;
- update_context_time(ctx);
- flags = hw_perf_save_disable();
- if (ctx->nr_active) {
- list_for_each_entry(counter, &ctx->counter_list, list_entry)
- group_sched_out(counter, cpuctx, ctx);
- }
- hw_perf_restore(flags);
- out:
- spin_unlock(&ctx->lock);
- }
- /*
- * 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, int cpu)
- {
- struct perf_cpu_context *cpuctx = &per_cpu(perf_cpu_context, cpu);
- struct perf_counter_context *ctx = &task->perf_counter_ctx;
- struct pt_regs *regs;
- if (likely(!cpuctx->task_ctx))
- return;
- update_context_time(ctx);
- regs = task_pt_regs(task);
- perf_swcounter_event(PERF_COUNT_CONTEXT_SWITCHES, 1, 1, regs, 0);
- __perf_counter_sched_out(ctx, cpuctx);
- cpuctx->task_ctx = NULL;
- }
- static void perf_counter_cpu_sched_out(struct perf_cpu_context *cpuctx)
- {
- __perf_counter_sched_out(&cpuctx->ctx, cpuctx);
- }
- 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;
- group_counter->prev_state = group_counter->state;
- 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) {
- counter->prev_state = counter->state;
- 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;
- }
- static void
- __perf_counter_sched_in(struct perf_counter_context *ctx,
- struct perf_cpu_context *cpuctx, int cpu)
- {
- struct perf_counter *counter;
- u64 flags;
- int can_add_hw = 1;
- spin_lock(&ctx->lock);
- ctx->is_active = 1;
- if (likely(!ctx->nr_counters))
- goto out;
- ctx->timestamp = perf_clock();
- flags = hw_perf_save_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->hw_event.pinned)
- continue;
- if (counter->cpu != -1 && counter->cpu != cpu)
- continue;
- 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->hw_event.pinned)
- continue;
- /*
- * Listen to the 'cpu' scheduling filter constraint
- * of counters:
- */
- if (counter->cpu != -1 && counter->cpu != cpu)
- continue;
- if (group_can_go_on(counter, cpuctx, can_add_hw)) {
- if (group_sched_in(counter, cpuctx, ctx, cpu))
- can_add_hw = 0;
- }
- }
- hw_perf_restore(flags);
- 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_ctx;
- __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);
- }
- int perf_counter_task_disable(void)
- {
- struct task_struct *curr = current;
- struct perf_counter_context *ctx = &curr->perf_counter_ctx;
- struct perf_counter *counter;
- unsigned long flags;
- u64 perf_flags;
- int cpu;
- if (likely(!ctx->nr_counters))
- return 0;
- local_irq_save(flags);
- cpu = smp_processor_id();
- perf_counter_task_sched_out(curr, cpu);
- spin_lock(&ctx->lock);
- /*
- * Disable all the counters:
- */
- perf_flags = hw_perf_save_disable();
- list_for_each_entry(counter, &ctx->counter_list, list_entry) {
- if (counter->state != PERF_COUNTER_STATE_ERROR) {
- update_group_times(counter);
- counter->state = PERF_COUNTER_STATE_OFF;
- }
- }
- hw_perf_restore(perf_flags);
- spin_unlock_irqrestore(&ctx->lock, flags);
- return 0;
- }
- int perf_counter_task_enable(void)
- {
- struct task_struct *curr = current;
- struct perf_counter_context *ctx = &curr->perf_counter_ctx;
- struct perf_counter *counter;
- unsigned long flags;
- u64 perf_flags;
- int cpu;
- if (likely(!ctx->nr_counters))
- return 0;
- local_irq_save(flags);
- cpu = smp_processor_id();
- perf_counter_task_sched_out(curr, cpu);
- spin_lock(&ctx->lock);
- /*
- * Disable all the counters:
- */
- perf_flags = hw_perf_save_disable();
- list_for_each_entry(counter, &ctx->counter_list, list_entry) {
- if (counter->state > PERF_COUNTER_STATE_OFF)
- continue;
- counter->state = PERF_COUNTER_STATE_INACTIVE;
- counter->tstamp_enabled =
- ctx->time - counter->total_time_enabled;
- counter->hw_event.disabled = 0;
- }
- hw_perf_restore(perf_flags);
- spin_unlock(&ctx->lock);
- perf_counter_task_sched_in(curr, cpu);
- local_irq_restore(flags);
- return 0;
- }
- /*
- * Round-robin a context's counters:
- */
- static void rotate_ctx(struct perf_counter_context *ctx)
- {
- struct perf_counter *counter;
- u64 perf_flags;
- if (!ctx->nr_counters)
- return;
- spin_lock(&ctx->lock);
- /*
- * Rotate the first entry last (works just fine for group counters too):
- */
- perf_flags = hw_perf_save_disable();
- list_for_each_entry(counter, &ctx->counter_list, list_entry) {
- list_move_tail(&counter->list_entry, &ctx->counter_list);
- break;
- }
- hw_perf_restore(perf_flags);
- spin_unlock(&ctx->lock);
- }
- void perf_counter_task_tick(struct task_struct *curr, int cpu)
- {
- struct perf_cpu_context *cpuctx = &per_cpu(perf_cpu_context, cpu);
- struct perf_counter_context *ctx = &curr->perf_counter_ctx;
- const int rotate_percpu = 0;
- if (rotate_percpu)
- perf_counter_cpu_sched_out(cpuctx);
- perf_counter_task_sched_out(curr, cpu);
- if (rotate_percpu)
- rotate_ctx(&cpuctx->ctx);
- rotate_ctx(ctx);
- if (rotate_percpu)
- perf_counter_cpu_sched_in(cpuctx, cpu);
- perf_counter_task_sched_in(curr, cpu);
- }
- /*
- * Cross CPU call to read the hardware counter
- */
- static void __read(void *info)
- {
- struct perf_counter *counter = info;
- struct perf_counter_context *ctx = counter->ctx;
- unsigned long flags;
- local_irq_save(flags);
- if (ctx->is_active)
- update_context_time(ctx);
- counter->hw_ops->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,
- __read, counter, 1);
- } else if (counter->state == PERF_COUNTER_STATE_INACTIVE) {
- update_counter_times(counter);
- }
- return atomic64_read(&counter->count);
- }
- static void put_context(struct perf_counter_context *ctx)
- {
- if (ctx->task)
- put_task_struct(ctx->task);
- }
- static struct perf_counter_context *find_get_context(pid_t pid, int cpu)
- {
- struct perf_cpu_context *cpuctx;
- struct perf_counter_context *ctx;
- struct task_struct *task;
- /*
- * 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 (sysctl_perf_counter_priv && !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;
- 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);
- ctx = &task->perf_counter_ctx;
- ctx->task = task;
- /* Reuse ptrace permission checks for now. */
- if (!ptrace_may_access(task, PTRACE_MODE_READ)) {
- put_context(ctx);
- return ERR_PTR(-EACCES);
- }
- return ctx;
- }
- static void free_counter_rcu(struct rcu_head *head)
- {
- struct perf_counter *counter;
- counter = container_of(head, struct perf_counter, rcu_head);
- 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->hw_event.mmap)
- atomic_dec(&nr_mmap_tracking);
- if (counter->hw_event.munmap)
- atomic_dec(&nr_munmap_tracking);
- if (counter->hw_event.comm)
- atomic_dec(&nr_comm_tracking);
- if (counter->destroy)
- counter->destroy(counter);
- 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;
- mutex_lock(&ctx->mutex);
- mutex_lock(&counter->mutex);
- perf_counter_remove_from_context(counter);
- mutex_unlock(&counter->mutex);
- mutex_unlock(&ctx->mutex);
- free_counter(counter);
- put_context(ctx);
- return 0;
- }
- /*
- * 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 values[3];
- int n;
- /*
- * 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;
- mutex_lock(&counter->mutex);
- values[0] = perf_counter_read(counter);
- n = 1;
- if (counter->hw_event.read_format & PERF_FORMAT_TOTAL_TIME_ENABLED)
- values[n++] = counter->total_time_enabled +
- atomic64_read(&counter->child_total_time_enabled);
- if (counter->hw_event.read_format & PERF_FORMAT_TOTAL_TIME_RUNNING)
- values[n++] = counter->total_time_running +
- atomic64_read(&counter->child_total_time_running);
- mutex_unlock(&counter->mutex);
- if (count < n * sizeof(u64))
- return -EINVAL;
- count = n * sizeof(u64);
- if (copy_to_user(buf, values, count))
- return -EFAULT;
- return count;
- }
- 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;
- rcu_read_lock();
- data = rcu_dereference(counter->data);
- if (data)
- events = atomic_xchg(&data->wakeup, 0);
- else
- events = POLL_HUP;
- rcu_read_unlock();
- poll_wait(file, &counter->waitq, wait);
- return events;
- }
- static long perf_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
- {
- struct perf_counter *counter = file->private_data;
- int err = 0;
- switch (cmd) {
- case PERF_COUNTER_IOC_ENABLE:
- perf_counter_enable_family(counter);
- break;
- case PERF_COUNTER_IOC_DISABLE:
- perf_counter_disable_family(counter);
- break;
- case PERF_COUNTER_IOC_REFRESH:
- perf_counter_refresh(counter, arg);
- break;
- default:
- err = -ENOTTY;
- }
- return err;
- }
- /*
- * 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_mmap_data *data;
- struct perf_counter_mmap_page *userpg;
- 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 = counter->hw.idx;
- userpg->offset = atomic64_read(&counter->count);
- if (counter->state == PERF_COUNTER_STATE_ACTIVE)
- userpg->offset -= atomic64_read(&counter->hw.prev_count);
- 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;
- 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;
- vmf->page = virt_to_page(data->data_pages[nr]);
- }
- get_page(vmf->page);
- 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;
- 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_data_free(struct rcu_head *rcu_head)
- {
- struct perf_mmap_data *data = container_of(rcu_head,
- struct perf_mmap_data, rcu_head);
- int i;
- free_page((unsigned long)data->user_page);
- for (i = 0; i < data->nr_pages; i++)
- 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;
- if (atomic_dec_and_mutex_lock(&counter->mmap_count,
- &counter->mmap_mutex)) {
- vma->vm_mm->locked_vm -= counter->data->nr_pages + 1;
- 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,
- };
- static int perf_mmap(struct file *file, struct vm_area_struct *vma)
- {
- struct perf_counter *counter = file->private_data;
- unsigned long vma_size;
- unsigned long nr_pages;
- unsigned long locked, lock_limit;
- int ret = 0;
- if (!(vma->vm_flags & VM_SHARED) || (vma->vm_flags & VM_WRITE))
- 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;
- mutex_lock(&counter->mmap_mutex);
- if (atomic_inc_not_zero(&counter->mmap_count)) {
- if (nr_pages != counter->data->nr_pages)
- ret = -EINVAL;
- goto unlock;
- }
- locked = vma->vm_mm->locked_vm;
- locked += nr_pages + 1;
- lock_limit = current->signal->rlim[RLIMIT_MEMLOCK].rlim_cur;
- lock_limit >>= PAGE_SHIFT;
- 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);
- vma->vm_mm->locked_vm += nr_pages + 1;
- unlock:
- mutex_unlock(&counter->mmap_mutex);
- vma->vm_flags &= ~VM_MAYWRITE;
- 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 perf_counter *counter = filp->private_data;
- struct inode *inode = filp->f_path.dentry->d_inode;
- 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)
- {
- struct perf_mmap_data *data;
- rcu_read_lock();
- data = rcu_dereference(counter->data);
- if (data) {
- atomic_set(&data->wakeup, POLL_IN);
- /*
- * Ensure all data writes are issued before updating the
- * user-space data head information. The matching rmb()
- * will be in userspace after reading this value.
- */
- smp_wmb();
- data->user_page->data_head = atomic_read(&data->head);
- }
- rcu_read_unlock();
- 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 int offset;
- unsigned int head;
- int wakeup;
- int nmi;
- int overflow;
- };
- static inline void __perf_output_wakeup(struct perf_output_handle *handle)
- {
- if (handle->nmi) {
- handle->counter->pending_wakeup = 1;
- perf_pending_queue(&handle->counter->pending,
- perf_pending_counter);
- } else
- perf_counter_wakeup(handle->counter);
- }
- static int perf_output_begin(struct perf_output_handle *handle,
- struct perf_counter *counter, unsigned int size,
- int nmi, int overflow)
- {
- struct perf_mmap_data *data;
- unsigned int offset, head;
- rcu_read_lock();
- data = rcu_dereference(counter->data);
- if (!data)
- goto out;
- handle->counter = counter;
- handle->nmi = nmi;
- handle->overflow = overflow;
- if (!data->nr_pages)
- goto fail;
- do {
- offset = head = atomic_read(&data->head);
- head += size;
- } while (atomic_cmpxchg(&data->head, offset, head) != offset);
- handle->data = data;
- handle->offset = offset;
- handle->head = head;
- handle->wakeup = (offset >> PAGE_SHIFT) != (head >> PAGE_SHIFT);
- return 0;
- fail:
- __perf_output_wakeup(handle);
- out:
- rcu_read_unlock();
- return -ENOSPC;
- }
- static void perf_output_copy(struct perf_output_handle *handle,
- 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;
- WARN_ON_ONCE(handle->offset > handle->head);
- }
- #define perf_output_put(handle, x) \
- perf_output_copy((handle), &(x), sizeof(x))
- static void perf_output_end(struct perf_output_handle *handle)
- {
- int wakeup_events = handle->counter->hw_event.wakeup_events;
- if (handle->overflow && wakeup_events) {
- int events = atomic_inc_return(&handle->data->events);
- if (events >= wakeup_events) {
- atomic_sub(wakeup_events, &handle->data->events);
- __perf_output_wakeup(handle);
- }
- } else if (handle->wakeup)
- __perf_output_wakeup(handle);
- rcu_read_unlock();
- }
- static void perf_counter_output(struct perf_counter *counter,
- int nmi, struct pt_regs *regs, u64 addr)
- {
- int ret;
- u64 record_type = counter->hw_event.record_type;
- struct perf_output_handle handle;
- struct perf_event_header header;
- u64 ip;
- struct {
- u32 pid, tid;
- } tid_entry;
- struct {
- u64 event;
- u64 counter;
- } group_entry;
- struct perf_callchain_entry *callchain = NULL;
- int callchain_size = 0;
- u64 time;
- header.type = 0;
- header.size = sizeof(header);
- header.misc = PERF_EVENT_MISC_OVERFLOW;
- header.misc |= user_mode(regs) ?
- PERF_EVENT_MISC_USER : PERF_EVENT_MISC_KERNEL;
- if (record_type & PERF_RECORD_IP) {
- ip = instruction_pointer(regs);
- header.type |= PERF_RECORD_IP;
- header.size += sizeof(ip);
- }
- if (record_type & PERF_RECORD_TID) {
- /* namespace issues */
- tid_entry.pid = current->group_leader->pid;
- tid_entry.tid = current->pid;
- header.type |= PERF_RECORD_TID;
- header.size += sizeof(tid_entry);
- }
- if (record_type & PERF_RECORD_TIME) {
- /*
- * Maybe do better on x86 and provide cpu_clock_nmi()
- */
- time = sched_clock();
- header.type |= PERF_RECORD_TIME;
- header.size += sizeof(u64);
- }
- if (record_type & PERF_RECORD_ADDR) {
- header.type |= PERF_RECORD_ADDR;
- header.size += sizeof(u64);
- }
- if (record_type & PERF_RECORD_GROUP) {
- header.type |= PERF_RECORD_GROUP;
- header.size += sizeof(u64) +
- counter->nr_siblings * sizeof(group_entry);
- }
- if (record_type & PERF_RECORD_CALLCHAIN) {
- callchain = perf_callchain(regs);
- if (callchain) {
- callchain_size = (1 + callchain->nr) * sizeof(u64);
- header.type |= PERF_RECORD_CALLCHAIN;
- header.size += callchain_size;
- }
- }
- ret = perf_output_begin(&handle, counter, header.size, nmi, 1);
- if (ret)
- return;
- perf_output_put(&handle, header);
- if (record_type & PERF_RECORD_IP)
- perf_output_put(&handle, ip);
- if (record_type & PERF_RECORD_TID)
- perf_output_put(&handle, tid_entry);
- if (record_type & PERF_RECORD_TIME)
- perf_output_put(&handle, time);
- if (record_type & PERF_RECORD_ADDR)
- perf_output_put(&handle, addr);
- if (record_type & PERF_RECORD_GROUP) {
- struct perf_counter *leader, *sub;
- u64 nr = counter->nr_siblings;
- perf_output_put(&handle, nr);
- leader = counter->group_leader;
- list_for_each_entry(sub, &leader->sibling_list, list_entry) {
- if (sub != counter)
- sub->hw_ops->read(sub);
- group_entry.event = sub->hw_event.config;
- group_entry.counter = atomic64_read(&sub->count);
- perf_output_put(&handle, group_entry);
- }
- }
- if (callchain)
- perf_output_copy(&handle, callchain, callchain_size);
- perf_output_end(&handle);
- }
- /*
- * 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;
- 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,
- struct perf_comm_event *comm_event)
- {
- if (counter->hw_event.comm &&
- comm_event->event.header.type == PERF_EVENT_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, comm_event))
- 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;
- unsigned int size;
- char *comm = comm_event->task->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);
- perf_counter_comm_ctx(¤t->perf_counter_ctx, comm_event);
- }
- void perf_counter_comm(struct task_struct *task)
- {
- struct perf_comm_event comm_event;
- if (!atomic_read(&nr_comm_tracking))
- return;
-
- comm_event = (struct perf_comm_event){
- .task = task,
- .event = {
- .header = { .type = PERF_EVENT_COMM, },
- .pid = task->group_leader->pid,
- .tid = task->pid,
- },
- };
- perf_counter_comm_event(&comm_event);
- }
- /*
- * mmap tracking
- */
- struct perf_mmap_event {
- struct file *file;
- 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;
- 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->hw_event.mmap &&
- mmap_event->event.header.type == PERF_EVENT_MMAP)
- return 1;
- if (counter->hw_event.munmap &&
- mmap_event->event.header.type == PERF_EVENT_MUNMAP)
- 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 file *file = mmap_event->file;
- unsigned int size;
- char tmp[16];
- char *buf = NULL;
- char *name;
- if (file) {
- buf = kzalloc(PATH_MAX, GFP_KERNEL);
- if (!buf) {
- name = strncpy(tmp, "//enomem", sizeof(tmp));
- goto got_name;
- }
- name = dentry_path(file->f_dentry, buf, PATH_MAX);
- if (IS_ERR(name)) {
- name = strncpy(tmp, "//toolong", sizeof(tmp));
- goto got_name;
- }
- } else {
- 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);
- perf_counter_mmap_ctx(¤t->perf_counter_ctx, mmap_event);
- kfree(buf);
- }
- void perf_counter_mmap(unsigned long addr, unsigned long len,
- unsigned long pgoff, struct file *file)
- {
- struct perf_mmap_event mmap_event;
- if (!atomic_read(&nr_mmap_tracking))
- return;
- mmap_event = (struct perf_mmap_event){
- .file = file,
- .event = {
- .header = { .type = PERF_EVENT_MMAP, },
- .pid = current->group_leader->pid,
- .tid = current->pid,
- .start = addr,
- .len = len,
- .pgoff = pgoff,
- },
- };
- perf_counter_mmap_event(&mmap_event);
- }
- void perf_counter_munmap(unsigned long addr, unsigned long len,
- unsigned long pgoff, struct file *file)
- {
- struct perf_mmap_event mmap_event;
- if (!atomic_read(&nr_munmap_tracking))
- return;
- mmap_event = (struct perf_mmap_event){
- .file = file,
- .event = {
- .header = { .type = PERF_EVENT_MUNMAP, },
- .pid = current->group_leader->pid,
- .tid = current->pid,
- .start = addr,
- .len = len,
- .pgoff = pgoff,
- },
- };
- perf_counter_mmap_event(&mmap_event);
- }
- /*
- * Generic counter overflow handling.
- */
- int perf_counter_overflow(struct perf_counter *counter,
- int nmi, struct pt_regs *regs, u64 addr)
- {
- int events = atomic_read(&counter->event_limit);
- int ret = 0;
- 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, regs, addr);
- return ret;
- }
- /*
- * Generic software counter infrastructure
- */
- static void perf_swcounter_update(struct perf_counter *counter)
- {
- struct hw_perf_counter *hwc = &counter->hw;
- u64 prev, now;
- s64 delta;
- again:
- prev = atomic64_read(&hwc->prev_count);
- now = atomic64_read(&hwc->count);
- if (atomic64_cmpxchg(&hwc->prev_count, prev, now) != prev)
- goto again;
- delta = now - prev;
- atomic64_add(delta, &counter->count);
- atomic64_sub(delta, &hwc->period_left);
- }
- static void perf_swcounter_set_period(struct perf_counter *counter)
- {
- struct hw_perf_counter *hwc = &counter->hw;
- s64 left = atomic64_read(&hwc->period_left);
- s64 period = hwc->irq_period;
- if (unlikely(left <= -period)) {
- left = period;
- atomic64_set(&hwc->period_left, left);
- }
- if (unlikely(left <= 0)) {
- left += period;
- atomic64_add(period, &hwc->period_left);
- }
- atomic64_set(&hwc->prev_count, -left);
- atomic64_set(&hwc->count, -left);
- }
- static enum hrtimer_restart perf_swcounter_hrtimer(struct hrtimer *hrtimer)
- {
- enum hrtimer_restart ret = HRTIMER_RESTART;
- struct perf_counter *counter;
- struct pt_regs *regs;
- counter = container_of(hrtimer, struct perf_counter, hw.hrtimer);
- counter->hw_ops->read(counter);
- 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->hw_event.exclude_kernel || !regs) &&
- !counter->hw_event.exclude_user)
- regs = task_pt_regs(current);
- if (regs) {
- if (perf_counter_overflow(counter, 0, regs, 0))
- ret = HRTIMER_NORESTART;
- }
- hrtimer_forward_now(hrtimer, ns_to_ktime(counter->hw.irq_period));
- return ret;
- }
- static void perf_swcounter_overflow(struct perf_counter *counter,
- int nmi, struct pt_regs *regs, u64 addr)
- {
- perf_swcounter_update(counter);
- perf_swcounter_set_period(counter);
- if (perf_counter_overflow(counter, nmi, regs, addr))
- /* soft-disable the counter */
- ;
- }
- static int perf_swcounter_match(struct perf_counter *counter,
- enum perf_event_types type,
- u32 event, struct pt_regs *regs)
- {
- if (counter->state != PERF_COUNTER_STATE_ACTIVE)
- return 0;
- if (perf_event_raw(&counter->hw_event))
- return 0;
- if (perf_event_type(&counter->hw_event) != type)
- return 0;
- if (perf_event_id(&counter->hw_event) != event)
- return 0;
- if (counter->hw_event.exclude_user && user_mode(regs))
- return 0;
- if (counter->hw_event.exclude_kernel && !user_mode(regs))
- return 0;
- return 1;
- }
- static void perf_swcounter_add(struct perf_counter *counter, u64 nr,
- int nmi, struct pt_regs *regs, u64 addr)
- {
- int neg = atomic64_add_negative(nr, &counter->hw.count);
- if (counter->hw.irq_period && !neg)
- perf_swcounter_overflow(counter, nmi, regs, addr);
- }
- static void perf_swcounter_ctx_event(struct perf_counter_context *ctx,
- enum perf_event_types type, u32 event,
- u64 nr, int nmi, struct pt_regs *regs,
- u64 addr)
- {
- 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, regs))
- perf_swcounter_add(counter, nr, nmi, regs, addr);
- }
- 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 __perf_swcounter_event(enum perf_event_types type, u32 event,
- u64 nr, int nmi, struct pt_regs *regs,
- u64 addr)
- {
- struct perf_cpu_context *cpuctx = &get_cpu_var(perf_cpu_context);
- int *recursion = perf_swcounter_recursion_context(cpuctx);
- if (*recursion)
- goto out;
- (*recursion)++;
- barrier();
- perf_swcounter_ctx_event(&cpuctx->ctx, type, event,
- nr, nmi, regs, addr);
- if (cpuctx->task_ctx) {
- perf_swcounter_ctx_event(cpuctx->task_ctx, type, event,
- nr, nmi, regs, addr);
- }
- 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)
- {
- __perf_swcounter_event(PERF_TYPE_SOFTWARE, event, nr, nmi, regs, addr);
- }
- static void perf_swcounter_read(struct perf_counter *counter)
- {
- perf_swcounter_update(counter);
- }
- static int perf_swcounter_enable(struct perf_counter *counter)
- {
- perf_swcounter_set_period(counter);
- return 0;
- }
- static void perf_swcounter_disable(struct perf_counter *counter)
- {
- perf_swcounter_update(counter);
- }
- static const struct hw_perf_counter_ops perf_ops_generic = {
- .enable = perf_swcounter_enable,
- .disable = perf_swcounter_disable,
- .read = perf_swcounter_read,
- };
- /*
- * 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->irq_period) {
- __hrtimer_start_range_ns(&hwc->hrtimer,
- ns_to_ktime(hwc->irq_period), 0,
- HRTIMER_MODE_REL, 0);
- }
- return 0;
- }
- static void cpu_clock_perf_counter_disable(struct perf_counter *counter)
- {
- 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 hw_perf_counter_ops 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->irq_period) {
- __hrtimer_start_range_ns(&hwc->hrtimer,
- ns_to_ktime(hwc->irq_period), 0,
- HRTIMER_MODE_REL, 0);
- }
- return 0;
- }
- static void task_clock_perf_counter_disable(struct perf_counter *counter)
- {
- 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 hw_perf_counter_ops perf_ops_task_clock = {
- .enable = task_clock_perf_counter_enable,
- .disable = task_clock_perf_counter_disable,
- .read = task_clock_perf_counter_read,
- };
- /*
- * Software counter: cpu migrations
- */
- static inline u64 get_cpu_migrations(struct perf_counter *counter)
- {
- struct task_struct *curr = counter->ctx->task;
- if (curr)
- return curr->se.nr_migrations;
- return cpu_nr_migrations(smp_processor_id());
- }
- static void cpu_migrations_perf_counter_update(struct perf_counter *counter)
- {
- u64 prev, now;
- s64 delta;
- prev = atomic64_read(&counter->hw.prev_count);
- now = get_cpu_migrations(counter);
- atomic64_set(&counter->hw.prev_count, now);
- delta = now - prev;
- atomic64_add(delta, &counter->count);
- }
- static void cpu_migrations_perf_counter_read(struct perf_counter *counter)
- {
- cpu_migrations_perf_counter_update(counter);
- }
- static int cpu_migrations_perf_counter_enable(struct perf_counter *counter)
- {
- if (counter->prev_state <= PERF_COUNTER_STATE_OFF)
- atomic64_set(&counter->hw.prev_count,
- get_cpu_migrations(counter));
- return 0;
- }
- static void cpu_migrations_perf_counter_disable(struct perf_counter *counter)
- {
- cpu_migrations_perf_counter_update(counter);
- }
- static const struct hw_perf_counter_ops perf_ops_cpu_migrations = {
- .enable = cpu_migrations_perf_counter_enable,
- .disable = cpu_migrations_perf_counter_disable,
- .read = cpu_migrations_perf_counter_read,
- };
- #ifdef CONFIG_EVENT_PROFILE
- void perf_tpcounter_event(int event_id)
- {
- struct pt_regs *regs = get_irq_regs();
- if (!regs)
- regs = task_pt_regs(current);
- __perf_swcounter_event(PERF_TYPE_TRACEPOINT, event_id, 1, 1, regs, 0);
- }
- 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(perf_event_id(&counter->hw_event));
- }
- static const struct hw_perf_counter_ops *
- tp_perf_counter_init(struct perf_counter *counter)
- {
- int event_id = perf_event_id(&counter->hw_event);
- int ret;
- ret = ftrace_profile_enable(event_id);
- if (ret)
- return NULL;
- counter->destroy = tp_perf_counter_destroy;
- counter->hw.irq_period = counter->hw_event.irq_period;
- return &perf_ops_generic;
- }
- #else
- static const struct hw_perf_counter_ops *
- tp_perf_counter_init(struct perf_counter *counter)
- {
- return NULL;
- }
- #endif
- static const struct hw_perf_counter_ops *
- sw_perf_counter_init(struct perf_counter *counter)
- {
- struct perf_counter_hw_event *hw_event = &counter->hw_event;
- const struct hw_perf_counter_ops *hw_ops = NULL;
- struct hw_perf_counter *hwc = &counter->hw;
- /*
- * 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 (perf_event_id(&counter->hw_event)) {
- case PERF_COUNT_CPU_CLOCK:
- hw_ops = &perf_ops_cpu_clock;
- if (hw_event->irq_period && hw_event->irq_period < 10000)
- hw_event->irq_period = 10000;
- break;
- case PERF_COUNT_TASK_CLOCK:
- /*
- * If the user instantiates this as a per-cpu counter,
- * use the cpu_clock counter instead.
- */
- if (counter->ctx->task)
- hw_ops = &perf_ops_task_clock;
- else
- hw_ops = &perf_ops_cpu_clock;
- if (hw_event->irq_period && hw_event->irq_period < 10000)
- hw_event->irq_period = 10000;
- break;
- case PERF_COUNT_PAGE_FAULTS:
- case PERF_COUNT_PAGE_FAULTS_MIN:
- case PERF_COUNT_PAGE_FAULTS_MAJ:
- case PERF_COUNT_CONTEXT_SWITCHES:
- hw_ops = &perf_ops_generic;
- break;
- case PERF_COUNT_CPU_MIGRATIONS:
- if (!counter->hw_event.exclude_kernel)
- hw_ops = &perf_ops_cpu_migrations;
- break;
- }
- if (hw_ops)
- hwc->irq_period = hw_event->irq_period;
- return hw_ops;
- }
- /*
- * Allocate and initialize a counter structure
- */
- static struct perf_counter *
- perf_counter_alloc(struct perf_counter_hw_event *hw_event,
- int cpu,
- struct perf_counter_context *ctx,
- struct perf_counter *group_leader,
- gfp_t gfpflags)
- {
- const struct hw_perf_counter_ops *hw_ops;
- struct perf_counter *counter;
- 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->mutex);
- 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);
- INIT_LIST_HEAD(&counter->child_list);
- counter->cpu = cpu;
- counter->hw_event = *hw_event;
- counter->group_leader = group_leader;
- counter->hw_ops = NULL;
- counter->ctx = ctx;
- counter->state = PERF_COUNTER_STATE_INACTIVE;
- if (hw_event->disabled)
- counter->state = PERF_COUNTER_STATE_OFF;
- hw_ops = NULL;
- if (perf_event_raw(hw_event)) {
- hw_ops = hw_perf_counter_init(counter);
- goto done;
- }
- switch (perf_event_type(hw_event)) {
- case PERF_TYPE_HARDWARE:
- hw_ops = hw_perf_counter_init(counter);
- break;
- case PERF_TYPE_SOFTWARE:
- hw_ops = sw_perf_counter_init(counter);
- break;
- case PERF_TYPE_TRACEPOINT:
- hw_ops = tp_perf_counter_init(counter);
- break;
- }
- done:
- err = 0;
- if (!hw_ops)
- err = -EINVAL;
- else if (IS_ERR(hw_ops))
- err = PTR_ERR(hw_ops);
- if (err) {
- kfree(counter);
- return ERR_PTR(err);
- }
- counter->hw_ops = hw_ops;
- if (counter->hw_event.mmap)
- atomic_inc(&nr_mmap_tracking);
- if (counter->hw_event.munmap)
- atomic_inc(&nr_munmap_tracking);
- if (counter->hw_event.comm)
- atomic_inc(&nr_comm_tracking);
- return counter;
- }
- /**
- * sys_perf_counter_open - open a performance counter, associate it to a task/cpu
- *
- * @hw_event_uptr: event type attributes for monitoring/sampling
- * @pid: target pid
- * @cpu: target cpu
- * @group_fd: group leader counter fd
- */
- SYSCALL_DEFINE5(perf_counter_open,
- const struct perf_counter_hw_event __user *, hw_event_uptr,
- pid_t, pid, int, cpu, int, group_fd, unsigned long, flags)
- {
- struct perf_counter *counter, *group_leader;
- struct perf_counter_hw_event hw_event;
- 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;
- if (copy_from_user(&hw_event, hw_event_uptr, sizeof(hw_event)) != 0)
- return -EFAULT;
- /*
- * 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 (hw_event.exclusive || hw_event.pinned)
- goto err_put_context;
- }
- counter = perf_counter_alloc(&hw_event, cpu, ctx, group_leader,
- 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;
- mutex_lock(&ctx->mutex);
- perf_install_in_context(ctx, counter, cpu);
- mutex_unlock(&ctx->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_context(ctx);
- goto out_fput;
- }
- /*
- * 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);
- ctx->task = task;
- }
- /*
- * 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->hw_event,
- parent_counter->cpu, child_ctx,
- group_leader, GFP_KERNEL);
- if (IS_ERR(child_counter))
- return child_counter;
- /*
- * Link it up in the child's context:
- */
- child_counter->task = child;
- add_counter_to_ctx(child_counter, child_ctx);
- child_counter->parent = parent_counter;
- /*
- * inherit into child's child as well:
- */
- child_counter->hw_event.inherit = 1;
- /*
- * 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
- */
- mutex_lock(&parent_counter->mutex);
- list_add_tail(&child_counter->child_list, &parent_counter->child_list);
- /*
- * Make the child state follow the state of the parent counter,
- * not its hw_event.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;
- mutex_unlock(&parent_counter->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 perf_counter *parent_counter)
- {
- u64 parent_val, child_val;
- parent_val = atomic64_read(&parent_counter->count);
- 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
- */
- mutex_lock(&parent_counter->mutex);
- list_del_init(&child_counter->child_list);
- mutex_unlock(&parent_counter->mutex);
- /*
- * Release the parent counter, if this was the last
- * reference to it.
- */
- fput(parent_counter->filp);
- }
- static void
- __perf_counter_exit_task(struct task_struct *child,
- struct perf_counter *child_counter,
- struct perf_counter_context *child_ctx)
- {
- struct perf_counter *parent_counter;
- struct perf_counter *sub, *tmp;
- /*
- * If we do not self-reap then we have to wait for the
- * child task to unschedule (it will happen for sure),
- * so that its counter is at its final count. (This
- * condition triggers rarely - child tasks usually get
- * off their CPU before the parent has a chance to
- * get this far into the reaping action)
- */
- if (child != current) {
- wait_task_inactive(child, 0);
- list_del_init(&child_counter->list_entry);
- update_counter_times(child_counter);
- } else {
- struct perf_cpu_context *cpuctx;
- unsigned long flags;
- u64 perf_flags;
- /*
- * Disable and unlink this counter.
- *
- * Be careful about zapping the list - IRQ/NMI context
- * could still be processing it:
- */
- local_irq_save(flags);
- perf_flags = hw_perf_save_disable();
- cpuctx = &__get_cpu_var(perf_cpu_context);
- group_sched_out(child_counter, cpuctx, child_ctx);
- update_counter_times(child_counter);
- list_del_init(&child_counter->list_entry);
- child_ctx->nr_counters--;
- hw_perf_restore(perf_flags);
- local_irq_restore(flags);
- }
- 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, parent_counter);
- list_for_each_entry_safe(sub, tmp, &child_counter->sibling_list,
- list_entry) {
- if (sub->parent) {
- sync_child_counter(sub, sub->parent);
- free_counter(sub);
- }
- }
- free_counter(child_counter);
- }
- }
- /*
- * When a child task exits, feed back counter values to parent counters.
- *
- * Note: we may be running in child context, but the PID is not hashed
- * anymore so new counters will not be added.
- */
- void perf_counter_exit_task(struct task_struct *child)
- {
- struct perf_counter *child_counter, *tmp;
- struct perf_counter_context *child_ctx;
- child_ctx = &child->perf_counter_ctx;
- if (likely(!child_ctx->nr_counters))
- return;
- list_for_each_entry_safe(child_counter, tmp, &child_ctx->counter_list,
- list_entry)
- __perf_counter_exit_task(child, child_counter, child_ctx);
- }
- /*
- * Initialize the perf_counter context in task_struct
- */
- void perf_counter_init_task(struct task_struct *child)
- {
- struct perf_counter_context *child_ctx, *parent_ctx;
- struct perf_counter *counter;
- struct task_struct *parent = current;
- child_ctx = &child->perf_counter_ctx;
- parent_ctx = &parent->perf_counter_ctx;
- __perf_counter_init_context(child_ctx, child);
- /*
- * This is executed from the parent task context, so inherit
- * counters that have been marked for cloning:
- */
- if (likely(!parent_ctx->nr_counters))
- return;
- /*
- * 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(counter, &parent_ctx->counter_list, list_entry) {
- if (!counter->hw_event.inherit)
- continue;
- if (inherit_group(counter, parent,
- parent_ctx, child, child_ctx))
- break;
- }
- mutex_unlock(&parent_ctx->mutex);
- }
- 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);
- mutex_lock(&perf_resource_mutex);
- cpuctx->max_pertask = perf_max_counters - perf_reserved_percpu;
- mutex_unlock(&perf_resource_mutex);
- 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_DOWN_PREPARE:
- case CPU_DOWN_PREPARE_FROZEN:
- perf_counter_exit_cpu(cpu);
- break;
- default:
- break;
- }
- return NOTIFY_OK;
- }
- static struct notifier_block __cpuinitdata perf_cpu_nb = {
- .notifier_call = perf_cpu_notify,
- };
- static int __init perf_counter_init(void)
- {
- perf_cpu_notify(&perf_cpu_nb, (unsigned long)CPU_UP_PREPARE,
- (void *)(long)smp_processor_id());
- register_cpu_notifier(&perf_cpu_nb);
- return 0;
- }
- early_initcall(perf_counter_init);
- 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;
- mutex_lock(&perf_resource_mutex);
- 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);
- }
- mutex_unlock(&perf_resource_mutex);
- 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;
- mutex_lock(&perf_resource_mutex);
- perf_overcommit = val;
- mutex_unlock(&perf_resource_mutex);
- 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);
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