Commit message: perf: Treat attr.config as u64 in perf_swevent_init()

Trinity discovered that we fail to check all 64 bits of
attr.config passed by user space, resulting to out-of-bounds
access of the perf_swevent_enabled array in
sw_perf_event_destroy().

Introduced in commit b0a873ebb ("perf: Register PMU
implementations").

Signed-off-by: Tommi Rantala <tt.rantala@gmail.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: davej@redhat.com
Cc: Paul Mackerras <paulus@samba.org>
Cc: Arnaldo Carvalho de Melo <acme@ghostprotocols.net>
Link: http://lkml.kernel.org/r/1365882554-30259-1-git-send-email-tt.rantala@gmail.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
CVE: CVE-2013-2094
CWE: CWE-189
Vulnerability description: The perf_swevent_init function in kernel/events/core.c in the Linux kernel before 3.8.9 uses an incorrect integer data type, which allows local users to gain privileges via a crafted perf_event_open system call.

Project: linux
File: core.c

SYSCALL_DEFINE5(perf_event_open,
		struct perf_event_attr __user *, attr_uptr,
		pid_t, pid, int, cpu, int, group_fd, unsigned long, flags)
{
	struct perf_event *group_leader = NULL, *output_event = NULL;
	struct perf_event *event, *sibling;
	struct perf_event_attr attr;
	struct perf_event_context *ctx;
	struct file *event_file = NULL;
	struct fd group = {NULL, 0};
	struct task_struct *task = NULL;
	struct pmu *pmu;
	int event_fd;
	int move_group = 0;
	int err;

	/* for future expandability... */
	if (flags & ~PERF_FLAG_ALL)
		return -EINVAL;

	err = perf_copy_attr(attr_uptr, &attr);
	if (err)
		return err;

	if (!attr.exclude_kernel) {
		if (perf_paranoid_kernel() && !capable(CAP_SYS_ADMIN))
			return -EACCES;
	}

	if (attr.freq) {
		if (attr.sample_freq > sysctl_perf_event_sample_rate)
			return -EINVAL;
	}

	/*
	 * In cgroup mode, the pid argument is used to pass the fd
	 * opened to the cgroup directory in cgroupfs. The cpu argument
	 * designates the cpu on which to monitor threads from that
	 * cgroup.
	 */
	if ((flags & PERF_FLAG_PID_CGROUP) && (pid == -1 || cpu == -1))
		return -EINVAL;

	event_fd = get_unused_fd();
	if (event_fd < 0)
		return event_fd;

	if (group_fd != -1) {
		err = perf_fget_light(group_fd, &group);
		if (err)
			goto err_fd;
		group_leader = group.file->private_data;
		if (flags & PERF_FLAG_FD_OUTPUT)
			output_event = group_leader;
		if (flags & PERF_FLAG_FD_NO_GROUP)
			group_leader = NULL;
	}

	if (pid != -1 && !(flags & PERF_FLAG_PID_CGROUP)) {
		task = find_lively_task_by_vpid(pid);
		if (IS_ERR(task)) {
			err = PTR_ERR(task);
			goto err_group_fd;
		}
	}

	get_online_cpus();

	event = perf_event_alloc(&attr, cpu, task, group_leader, NULL,
				 NULL, NULL);
	if (IS_ERR(event)) {
		err = PTR_ERR(event);
		goto err_task;
	}

	if (flags & PERF_FLAG_PID_CGROUP) {
		err = perf_cgroup_connect(pid, event, &attr, group_leader);
		if (err)
			goto err_alloc;
		/*
		 * one more event:
		 * - that has cgroup constraint on event->cpu
		 * - that may need work on context switch
		 */
		atomic_inc(&per_cpu(perf_cgroup_events, event->cpu));
		static_key_slow_inc(&perf_sched_events.key);
	}

	/*
	 * Special case software events and allow them to be part of
	 * any hardware group.
	 */
	pmu = event->pmu;

	if (group_leader &&
	    (is_software_event(event) != is_software_event(group_leader))) {
		if (is_software_event(event)) {
			/*
			 * If event and group_leader are not both a software
			 * event, and event is, then group leader is not.
			 *
			 * Allow the addition of software events to !software
			 * groups, this is safe because software events never
			 * fail to schedule.
			 */
			pmu = group_leader->pmu;
		} else if (is_software_event(group_leader) &&
			   (group_leader->group_flags & PERF_GROUP_SOFTWARE)) {
			/*
			 * In case the group is a pure software group, and we
			 * try to add a hardware event, move the whole group to
			 * the hardware context.
			 */
			move_group = 1;
		}
	}

	/*
	 * Get the target context (task or percpu):
	 */
	ctx = find_get_context(pmu, task, event->cpu);
	if (IS_ERR(ctx)) {
		err = PTR_ERR(ctx);
		goto err_alloc;
	}

	if (task) {
		put_task_struct(task);
		task = NULL;
	}

	/*
	 * Look up the group leader (we will attach this event to it):
	 */
	if (group_leader) {
		err = -EINVAL;

		/*
		 * Do not allow a recursive hierarchy (this new sibling
		 * becoming part of another group-sibling):
		 */
		if (group_leader->group_leader != group_leader)
			goto err_context;
		/*
		 * Do not allow to attach to a group in a different
		 * task or CPU context:
		 */
		if (move_group) {
			if (group_leader->ctx->type != ctx->type)
				goto err_context;
		} else {
			if (group_leader->ctx != ctx)
				goto err_context;
		}

		/*
		 * Only a group leader can be exclusive or pinned
		 */
		if (attr.exclusive || attr.pinned)
			goto err_context;
	}

	if (output_event) {
		err = perf_event_set_output(event, output_event);
		if (err)
			goto err_context;
	}

	event_file = anon_inode_getfile("[perf_event]", &perf_fops, event, O_RDWR);
	if (IS_ERR(event_file)) {
		err = PTR_ERR(event_file);
		goto err_context;
	}

	if (move_group) {
		struct perf_event_context *gctx = group_leader->ctx;

		mutex_lock(&gctx->mutex);
		perf_remove_from_context(group_leader);

		/*
		 * Removing from the context ends up with disabled
		 * event. What we want here is event in the initial
		 * startup state, ready to be add into new context.
		 */
		perf_event__state_init(group_leader);
		list_for_each_entry(sibling, &group_leader->sibling_list,
				    group_entry) {
			perf_remove_from_context(sibling);
			perf_event__state_init(sibling);
			put_ctx(gctx);
		}
		mutex_unlock(&gctx->mutex);
		put_ctx(gctx);
	}

	WARN_ON_ONCE(ctx->parent_ctx);
	mutex_lock(&ctx->mutex);

	if (move_group) {
		synchronize_rcu();
		perf_install_in_context(ctx, group_leader, event->cpu);
		get_ctx(ctx);
		list_for_each_entry(sibling, &group_leader->sibling_list,
				    group_entry) {
			perf_install_in_context(ctx, sibling, event->cpu);
			get_ctx(ctx);
		}
	}

	perf_install_in_context(ctx, event, event->cpu);
	++ctx->generation;
	perf_unpin_context(ctx);
	mutex_unlock(&ctx->mutex);

	put_online_cpus();

	event->owner = current;

	mutex_lock(&current->perf_event_mutex);
	list_add_tail(&event->owner_entry, &current->perf_event_list);
	mutex_unlock(&current->perf_event_mutex);

	/*
	 * Precalculate sample_data sizes
	 */
	perf_event__header_size(event);
	perf_event__id_header_size(event);

	/*
	 * Drop the reference on the group_event after placing the
	 * new event on the sibling_list. This ensures destruction
	 * of the group leader will find the pointer to itself in
	 * perf_group_detach().
	 */
	fdput(group);
	fd_install(event_fd, event_file);
	return event_fd;

err_context:
	perf_unpin_context(ctx);
	put_ctx(ctx);
err_alloc:
	free_event(event);
err_task:
	put_online_cpus();
	if (task)
		put_task_struct(task);
err_group_fd:
	fdput(group);
err_fd:
	put_unused_fd(event_fd);
	return err;
}

Project: linux
File: core.c

static void __perf_event_mark_enabled(struct perf_event *event)
{
	struct perf_event *sub;
	u64 tstamp = perf_event_time(event);

	event->state = PERF_EVENT_STATE_INACTIVE;
	event->tstamp_enabled = tstamp - event->total_time_enabled;
	list_for_each_entry(sub, &event->sibling_list, group_entry) {
		if (sub->state >= PERF_EVENT_STATE_INACTIVE)
			sub->tstamp_enabled = tstamp - sub->total_time_enabled;
	}
}

Project: linux
File: core.c

static int __perf_event_overflow(struct perf_event *event,
				   int throttle, struct perf_sample_data *data,
				   struct pt_regs *regs)
{
	int events = atomic_read(&event->event_limit);
	struct hw_perf_event *hwc = &event->hw;
	u64 seq;
	int ret = 0;

	/*
	 * Non-sampling counters might still use the PMI to fold short
	 * hardware counters, ignore those.
	 */
	if (unlikely(!is_sampling_event(event)))
		return 0;

	seq = __this_cpu_read(perf_throttled_seq);
	if (seq != hwc->interrupts_seq) {
		hwc->interrupts_seq = seq;
		hwc->interrupts = 1;
	} else {
		hwc->interrupts++;
		if (unlikely(throttle
			     && hwc->interrupts >= max_samples_per_tick)) {
			__this_cpu_inc(perf_throttled_count);
			hwc->interrupts = MAX_INTERRUPTS;
			perf_log_throttle(event, 0);
			ret = 1;
		}
	}

	if (event->attr.freq) {
		u64 now = perf_clock();
		s64 delta = now - hwc->freq_time_stamp;

		hwc->freq_time_stamp = now;

		if (delta > 0 && delta < 2*TICK_NSEC)
			perf_adjust_period(event, delta, hwc->last_period, true);
	}

	/*
	 * XXX event_limit might not quite work as expected on inherited
	 * events
	 */

	event->pending_kill = POLL_IN;
	if (events && atomic_dec_and_test(&event->event_limit)) {
		ret = 1;
		event->pending_kill = POLL_HUP;
		event->pending_disable = 1;
		irq_work_queue(&event->pending);
	}

	if (event->overflow_handler)
		event->overflow_handler(event, data, regs);
	else
		perf_event_output(event, data, regs);

	if (event->fasync && event->pending_kill) {
		event->pending_wakeup = 1;
		irq_work_queue(&event->pending);
	}

	return ret;
}

Project: linux
File: core.c

void __perf_event_task_sched_in(struct task_struct *prev,
				struct task_struct *task)
{
	struct perf_event_context *ctx;
	int ctxn;

	for_each_task_context_nr(ctxn) {
		ctx = task->perf_event_ctxp[ctxn];
		if (likely(!ctx))
			continue;

		perf_event_context_sched_in(ctx, task);
	}
	/*
	 * if cgroup events exist on this CPU, then we need
	 * to check if we have to switch in PMU state.
	 * cgroup event are system-wide mode only
	 */
	if (atomic_read(&__get_cpu_var(perf_cgroup_events)))
		perf_cgroup_sched_in(prev, task);

	/* check for system-wide branch_stack events */
	if (atomic_read(&__get_cpu_var(perf_branch_stack_events)))
		perf_branch_stack_sched_in(prev, task);
}

Project: linux
File: core.c

void __perf_event_task_sched_out(struct task_struct *task,
				 struct task_struct *next)
{
	int ctxn;

	for_each_task_context_nr(ctxn)
		perf_event_context_sched_out(task, ctxn, next);

	/*
	 * if cgroup events exist on this CPU, then we need
	 * to check if we have to switch out PMU state.
	 * cgroup event are system-wide mode only
	 */
	if (atomic_read(&__get_cpu_var(perf_cgroup_events)))
		perf_cgroup_sched_out(task, next);
}

Project: linux
File: core.c

void __perf_sw_event(u32 event_id, u64 nr, struct pt_regs *regs, u64 addr)
{
	struct perf_sample_data data;
	int rctx;

	preempt_disable_notrace();
	rctx = perf_swevent_get_recursion_context();
	if (rctx < 0)
		return;

	perf_sample_data_init(&data, addr, 0);

	do_perf_sw_event(PERF_TYPE_SOFTWARE, event_id, nr, &data, regs);

	perf_swevent_put_recursion_context(rctx);
	preempt_enable_notrace();
}

Project: linux
File: core.c

void __weak arch_perf_update_userpage(struct perf_event_mmap_page *userpg, u64 now)
{
}

Project: linux
File: core.c

static int cpu_clock_event_init(struct perf_event *event)
{
	if (event->attr.type != PERF_TYPE_SOFTWARE)
		return -ENOENT;

	if (event->attr.config != PERF_COUNT_SW_CPU_CLOCK)
		return -ENOENT;

	/*
	 * no branch sampling for software events
	 */
	if (has_branch_stack(event))
		return -EOPNOTSUPP;

	perf_swevent_init_hrtimer(event);

	return 0;
}

Project: linux
File: core.c

static void do_perf_sw_event(enum perf_type_id type, u32 event_id,
				    u64 nr,
				    struct perf_sample_data *data,
				    struct pt_regs *regs)
{
	struct swevent_htable *swhash = &__get_cpu_var(swevent_htable);
	struct perf_event *event;
	struct hlist_head *head;

	rcu_read_lock();
	head = find_swevent_head_rcu(swhash, type, event_id);
	if (!head)
		goto end;

	hlist_for_each_entry_rcu(event, head, hlist_entry) {
		if (perf_swevent_match(event, type, event_id, data, regs))
			perf_swevent_event(event, nr, data, regs);
	}
end:
	rcu_read_unlock();
}

Project: linux
File: core.c

event_sched_in(struct perf_event *event,
		 struct perf_cpu_context *cpuctx,
		 struct perf_event_context *ctx)
{
	u64 tstamp = perf_event_time(event);

	if (event->state <= PERF_EVENT_STATE_OFF)
		return 0;

	event->state = PERF_EVENT_STATE_ACTIVE;
	event->oncpu = smp_processor_id();

	/*
	 * Unthrottle events, since we scheduled we might have missed several
	 * ticks already, also for a heavily scheduling task there is little
	 * guarantee it'll get a tick in a timely manner.
	 */
	if (unlikely(event->hw.interrupts == MAX_INTERRUPTS)) {
		perf_log_throttle(event, 1);
		event->hw.interrupts = 0;
	}

	/*
	 * The new state must be visible before we turn it on in the hardware:
	 */
	smp_wmb();

	if (event->pmu->add(event, PERF_EF_START)) {
		event->state = PERF_EVENT_STATE_INACTIVE;
		event->oncpu = -1;
		return -EAGAIN;
	}

	event->tstamp_running += tstamp - event->tstamp_stopped;

	perf_set_shadow_time(event, ctx, tstamp);

	if (!is_software_event(event))
		cpuctx->active_oncpu++;
	ctx->nr_active++;
	if (event->attr.freq && event->attr.sample_freq)
		ctx->nr_freq++;

	if (event->attr.exclusive)
		cpuctx->exclusive = 1;

	return 0;
}

Project: linux
File: core.c

event_sched_out(struct perf_event *event,
		  struct perf_cpu_context *cpuctx,
		  struct perf_event_context *ctx)
{
	u64 tstamp = perf_event_time(event);
	u64 delta;
	/*
	 * An event which could not be activated because of
	 * filter mismatch still needs to have its timings
	 * maintained, otherwise bogus information is return
	 * via read() for time_enabled, time_running:
	 */
	if (event->state == PERF_EVENT_STATE_INACTIVE
	    && !event_filter_match(event)) {
		delta = tstamp - event->tstamp_stopped;
		event->tstamp_running += delta;
		event->tstamp_stopped = tstamp;
	}

	if (event->state != PERF_EVENT_STATE_ACTIVE)
		return;

	event->state = PERF_EVENT_STATE_INACTIVE;
	if (event->pending_disable) {
		event->pending_disable = 0;
		event->state = PERF_EVENT_STATE_OFF;
	}
	event->tstamp_stopped = tstamp;
	event->pmu->del(event, 0);
	event->oncpu = -1;

	if (!is_software_event(event))
		cpuctx->active_oncpu--;
	ctx->nr_active--;
	if (event->attr.freq && event->attr.sample_freq)
		ctx->nr_freq--;
	if (event->attr.exclusive || !cpuctx->active_oncpu)
		cpuctx->exclusive = 0;
}

Project: linux
File: core.c

static void free_event(struct perf_event *event)
{
	irq_work_sync(&event->pending);

	if (!event->parent) {
		if (event->attach_state & PERF_ATTACH_TASK)
			static_key_slow_dec_deferred(&perf_sched_events);
		if (event->attr.mmap || event->attr.mmap_data)
			atomic_dec(&nr_mmap_events);
		if (event->attr.comm)
			atomic_dec(&nr_comm_events);
		if (event->attr.task)
			atomic_dec(&nr_task_events);
		if (event->attr.sample_type & PERF_SAMPLE_CALLCHAIN)
			put_callchain_buffers();
		if (is_cgroup_event(event)) {
			atomic_dec(&per_cpu(perf_cgroup_events, event->cpu));
			static_key_slow_dec_deferred(&perf_sched_events);
		}

		if (has_branch_stack(event)) {
			static_key_slow_dec_deferred(&perf_sched_events);
			/* is system-wide event */
			if (!(event->attach_state & PERF_ATTACH_TASK))
				atomic_dec(&per_cpu(perf_branch_stack_events,
						    event->cpu));
		}
	}

	if (event->rb) {
		ring_buffer_put(event->rb);
		event->rb = NULL;
	}

	if (is_cgroup_event(event))
		perf_detach_cgroup(event);

	if (event->destroy)
		event->destroy(event);

	if (event->ctx)
		put_ctx(event->ctx);

	call_rcu(&event->rcu_head, free_event_rcu);
}

Project: linux
File: core.c

inherit_event(struct perf_event *parent_event,
	      struct task_struct *parent,
	      struct perf_event_context *parent_ctx,
	      struct task_struct *child,
	      struct perf_event *group_leader,
	      struct perf_event_context *child_ctx)
{
	struct perf_event *child_event;
	unsigned long flags;

	/*
	 * Instead of creating recursive hierarchies of events,
	 * we link inherited events back to the original parent,
	 * which has a filp for sure, which we use as the reference
	 * count:
	 */
	if (parent_event->parent)
		parent_event = parent_event->parent;

	child_event = perf_event_alloc(&parent_event->attr,
					   parent_event->cpu,
					   child,
					   group_leader, parent_event,
				           NULL, NULL);
	if (IS_ERR(child_event))
		return child_event;

	if (!atomic_long_inc_not_zero(&parent_event->refcount)) {
		free_event(child_event);
		return NULL;
	}

	get_ctx(child_ctx);

	/*
	 * Make the child state follow the state of the parent event,
	 * not its attr.disabled bit.  We hold the parent's mutex,
	 * so we won't race with perf_event_{en, dis}able_family.
	 */
	if (parent_event->state >= PERF_EVENT_STATE_INACTIVE)
		child_event->state = PERF_EVENT_STATE_INACTIVE;
	else
		child_event->state = PERF_EVENT_STATE_OFF;

	if (parent_event->attr.freq) {
		u64 sample_period = parent_event->hw.sample_period;
		struct hw_perf_event *hwc = &child_event->hw;

		hwc->sample_period = sample_period;
		hwc->last_period   = sample_period;

		local64_set(&hwc->period_left, sample_period);
	}

	child_event->ctx = child_ctx;
	child_event->overflow_handler = parent_event->overflow_handler;
	child_event->overflow_handler_context
		= parent_event->overflow_handler_context;

	/*
	 * Precalculate sample_data sizes
	 */
	perf_event__header_size(child_event);
	perf_event__id_header_size(child_event);

	/*
	 * Link it up in the child's context:
	 */
	raw_spin_lock_irqsave(&child_ctx->lock, flags);
	add_event_to_ctx(child_event, child_ctx);
	raw_spin_unlock_irqrestore(&child_ctx->lock, flags);

	/*
	 * Link this into the parent event's child list
	 */
	WARN_ON_ONCE(parent_event->ctx->parent_ctx);
	mutex_lock(&parent_event->child_mutex);
	list_add_tail(&child_event->child_list, &parent_event->child_list);
	mutex_unlock(&parent_event->child_mutex);

	return child_event;
}

Project: linux
File: core.c

list_add_event(struct perf_event *event, struct perf_event_context *ctx)
{
	WARN_ON_ONCE(event->attach_state & PERF_ATTACH_CONTEXT);
	event->attach_state |= PERF_ATTACH_CONTEXT;

	/*
	 * If we're a stand alone event or group leader, we go to the context
	 * list, group events are kept attached to the group so that
	 * perf_group_detach can, at all times, locate all siblings.
	 */
	if (event->group_leader == event) {
		struct list_head *list;

		if (is_software_event(event))
			event->group_flags |= PERF_GROUP_SOFTWARE;

		list = ctx_group_list(event, ctx);
		list_add_tail(&event->group_entry, list);
	}

	if (is_cgroup_event(event))
		ctx->nr_cgroups++;

	if (has_branch_stack(event))
		ctx->nr_branch_stack++;

	list_add_rcu(&event->event_entry, &ctx->event_list);
	if (!ctx->nr_events)
		perf_pmu_rotate_start(ctx->pmu);
	ctx->nr_events++;
	if (event->attr.inherit_stat)
		ctx->nr_stat++;
}

Project: linux
File: core.c

list_del_event(struct perf_event *event, struct perf_event_context *ctx)
{
	struct perf_cpu_context *cpuctx;
	/*
	 * We can have double detach due to exit/hot-unplug + close.
	 */
	if (!(event->attach_state & PERF_ATTACH_CONTEXT))
		return;

	event->attach_state &= ~PERF_ATTACH_CONTEXT;

	if (is_cgroup_event(event)) {
		ctx->nr_cgroups--;
		cpuctx = __get_cpu_context(ctx);
		/*
		 * if there are no more cgroup events
		 * then cler cgrp to avoid stale pointer
		 * in update_cgrp_time_from_cpuctx()
		 */
		if (!ctx->nr_cgroups)
			cpuctx->cgrp = NULL;
	}

	if (has_branch_stack(event))
		ctx->nr_branch_stack--;

	ctx->nr_events--;
	if (event->attr.inherit_stat)
		ctx->nr_stat--;

	list_del_rcu(&event->event_entry);

	if (event->group_leader == event)
		list_del_init(&event->group_entry);

	update_group_times(event);

	/*
	 * If event was in error state, then keep it
	 * that way, otherwise bogus counts will be
	 * returned on read(). The only way to get out
	 * of error state is by explicit re-enabling
	 * of the event
	 */
	if (event->state > PERF_EVENT_STATE_OFF)
		event->state = PERF_EVENT_STATE_OFF;
}

Project: linux
File: core.c

static void perf_adjust_freq_unthr_context(struct perf_event_context *ctx,
					   int needs_unthr)
{
	struct perf_event *event;
	struct hw_perf_event *hwc;
	u64 now, period = TICK_NSEC;
	s64 delta;

	/*
	 * only need to iterate over all events iff:
	 * - context have events in frequency mode (needs freq adjust)
	 * - there are events to unthrottle on this cpu
	 */
	if (!(ctx->nr_freq || needs_unthr))
		return;

	raw_spin_lock(&ctx->lock);
	perf_pmu_disable(ctx->pmu);

	list_for_each_entry_rcu(event, &ctx->event_list, event_entry) {
		if (event->state != PERF_EVENT_STATE_ACTIVE)
			continue;

		if (!event_filter_match(event))
			continue;

		hwc = &event->hw;

		if (needs_unthr && hwc->interrupts == MAX_INTERRUPTS) {
			hwc->interrupts = 0;
			perf_log_throttle(event, 1);
			event->pmu->start(event, 0);
		}

		if (!event->attr.freq || !event->attr.sample_freq)
			continue;

		/*
		 * stop the event and update event->count
		 */
		event->pmu->stop(event, PERF_EF_UPDATE);

		now = local64_read(&event->count);
		delta = now - hwc->freq_count_stamp;
		hwc->freq_count_stamp = now;

		/*
		 * restart the event
		 * reload only if value has changed
		 * we have stopped the event so tell that
		 * to perf_adjust_period() to avoid stopping it
		 * twice.
		 */
		if (delta > 0)
			perf_adjust_period(event, period, delta, false);

		event->pmu->start(event, delta > 0 ? PERF_EF_RELOAD : 0);
	}

	perf_pmu_enable(ctx->pmu);
	raw_spin_unlock(&ctx->lock);
}

Project: linux
File: core.c

static void perf_adjust_period(struct perf_event *event, u64 nsec, u64 count, bool disable)
{
	struct hw_perf_event *hwc = &event->hw;
	s64 period, sample_period;
	s64 delta;

	period = perf_calculate_period(event, nsec, count);

	delta = (s64)(period - hwc->sample_period);
	delta = (delta + 7) / 8; /* low pass filter */

	sample_period = hwc->sample_period + delta;

	if (!sample_period)
		sample_period = 1;

	hwc->sample_period = sample_period;

	if (local64_read(&hwc->period_left) > 8*sample_period) {
		if (disable)
			event->pmu->stop(event, PERF_EF_UPDATE);

		local64_set(&hwc->period_left, 0);

		if (disable)
			event->pmu->start(event, PERF_EF_RELOAD);
	}
}

Project: linux
File: core.c

void perf_bp_event(struct perf_event *bp, void *data)
{
	struct perf_sample_data sample;
	struct pt_regs *regs = data;

	perf_sample_data_init(&sample, bp->attr.bp_addr, 0);

	if (!bp->hw.state && !perf_exclude_event(bp, regs))
		perf_swevent_event(bp, 1, &sample, regs);
}

Project: linux
File: core.c

static void perf_branch_stack_sched_in(struct task_struct *prev,
				       struct task_struct *task)
{
	struct perf_cpu_context *cpuctx;
	struct pmu *pmu;
	unsigned long flags;

	/* no need to flush branch stack if not changing task */
	if (prev == task)
		return;

	local_irq_save(flags);

	rcu_read_lock();

	list_for_each_entry_rcu(pmu, &pmus, entry) {
		cpuctx = this_cpu_ptr(pmu->pmu_cpu_context);

		/*
		 * check if the context has at least one
		 * event using PERF_SAMPLE_BRANCH_STACK
		 */
		if (cpuctx->ctx.nr_branch_stack > 0
		    && pmu->flush_branch_stack) {

			pmu = cpuctx->ctx.pmu;

			perf_ctx_lock(cpuctx, cpuctx->task_ctx);

			perf_pmu_disable(pmu);

			pmu->flush_branch_stack();

			perf_pmu_enable(pmu);

			perf_ctx_unlock(cpuctx, cpuctx->task_ctx);
		}
	}

	rcu_read_unlock();

	local_irq_restore(flags);
}

Project: linux
File: core.c

static void perf_cgroup_attach(struct cgroup *cgrp, struct cgroup_taskset *tset)
{
	struct task_struct *task;

	cgroup_taskset_for_each(task, cgrp, tset)
		task_function_call(task, __perf_cgroup_move, task);
}

Project: linux
File: core.c

static inline int perf_cgroup_connect(int fd, struct perf_event *event,
				      struct perf_event_attr *attr,
				      struct perf_event *group_leader)
{
	struct perf_cgroup *cgrp;
	struct cgroup_subsys_state *css;
	struct fd f = fdget(fd);
	int ret = 0;

	if (!f.file)
		return -EBADF;

	css = cgroup_css_from_dir(f.file, perf_subsys_id);
	if (IS_ERR(css)) {
		ret = PTR_ERR(css);
		goto out;
	}

	cgrp = container_of(css, struct perf_cgroup, css);
	event->cgrp = cgrp;

	/* must be done before we fput() the file */
	if (!perf_tryget_cgroup(event)) {
		event->cgrp = NULL;
		ret = -ENOENT;
		goto out;
	}

	/*
	 * all events in a group must monitor
	 * the same cgroup because a task belongs
	 * to only one perf cgroup at a time
	 */
	if (group_leader && group_leader->cgrp != cgrp) {
		perf_detach_cgroup(event);
		ret = -EINVAL;
	}
out:
	fdput(f);
	return ret;
}

Project: linux
File: core.c

static struct cgroup_subsys_state *perf_cgroup_css_alloc(struct cgroup *cont)
{
	struct perf_cgroup *jc;

	jc = kzalloc(sizeof(*jc), GFP_KERNEL);
	if (!jc)
		return ERR_PTR(-ENOMEM);

	jc->info = alloc_percpu(struct perf_cgroup_info);
	if (!jc->info) {
		kfree(jc);
		return ERR_PTR(-ENOMEM);
	}

	return &jc->css;
}

Project: linux
File: core.c

static void perf_cgroup_css_free(struct cgroup *cont)
{
	struct perf_cgroup *jc;
	jc = container_of(cgroup_subsys_state(cont, perf_subsys_id),
			  struct perf_cgroup, css);
	free_percpu(jc->info);
	kfree(jc);
}

Project: linux
File: core.c

static void perf_cgroup_exit(struct cgroup *cgrp, struct cgroup *old_cgrp,
			     struct task_struct *task)
{
	/*
	 * cgroup_exit() is called in the copy_process() failure path.
	 * Ignore this case since the task hasn't ran yet, this avoids
	 * trying to poke a half freed task state from generic code.
	 */
	if (!(task->flags & PF_EXITING))
		return;

	task_function_call(task, __perf_cgroup_move, task);
}

Project: linux
File: core.c

static inline void perf_cgroup_sched_in(struct task_struct *prev,
					struct task_struct *task)
{
}

Project: linux
File: core.c

static inline void perf_cgroup_sched_out(struct task_struct *task,
					 struct task_struct *next)
{
	struct perf_cgroup *cgrp1;
	struct perf_cgroup *cgrp2 = NULL;

	/*
	 * we come here when we know perf_cgroup_events > 0
	 */
	cgrp1 = perf_cgroup_from_task(task);

	/*
	 * next is NULL when called from perf_event_enable_on_exec()
	 * that will systematically cause a cgroup_switch()
	 */
	if (next)
		cgrp2 = perf_cgroup_from_task(next);

	/*
	 * only schedule out current cgroup events if we know
	 * that we are switching to a different cgroup. Otherwise,
	 * do no touch the cgroup events.
	 */
	if (cgrp1 != cgrp2)
		perf_cgroup_switch(task, PERF_CGROUP_SWOUT);
}

Project: linux
File: core.c

static inline void perf_cgroup_sched_out(struct task_struct *task,
					 struct task_struct *next)
{
}

Project: linux
File: core.c

void perf_cgroup_switch(struct task_struct *task, int mode)
{
	struct perf_cpu_context *cpuctx;
	struct pmu *pmu;
	unsigned long flags;

	/*
	 * disable interrupts to avoid geting nr_cgroup
	 * changes via __perf_event_disable(). Also
	 * avoids preemption.
	 */
	local_irq_save(flags);

	/*
	 * we reschedule only in the presence of cgroup
	 * constrained events.
	 */
	rcu_read_lock();

	list_for_each_entry_rcu(pmu, &pmus, entry) {
		cpuctx = this_cpu_ptr(pmu->pmu_cpu_context);
		if (cpuctx->unique_pmu != pmu)
			continue; /* ensure we process each cpuctx once */

		/*
		 * perf_cgroup_events says at least one
		 * context on this CPU has cgroup events.
		 *
		 * ctx->nr_cgroups reports the number of cgroup
		 * events for a context.
		 */
		if (cpuctx->ctx.nr_cgroups > 0) {
			perf_ctx_lock(cpuctx, cpuctx->task_ctx);
			perf_pmu_disable(cpuctx->ctx.pmu);

			if (mode & PERF_CGROUP_SWOUT) {
				cpu_ctx_sched_out(cpuctx, EVENT_ALL);
				/*
				 * must not be done before ctxswout due
				 * to event_filter_match() in event_sched_out()
				 */
				cpuctx->cgrp = NULL;
			}

			if (mode & PERF_CGROUP_SWIN) {
				WARN_ON_ONCE(cpuctx->cgrp);
				/*
				 * set cgrp before ctxsw in to allow
				 * event_filter_match() to not have to pass
				 * task around
				 */
				cpuctx->cgrp = perf_cgroup_from_task(task);
				cpu_ctx_sched_in(cpuctx, EVENT_ALL, task);
			}
			perf_pmu_enable(cpuctx->ctx.pmu);
			perf_ctx_unlock(cpuctx, cpuctx->task_ctx);
		}
	}

	rcu_read_unlock();

	local_irq_restore(flags);
}

Project: linux
File: core.c

static int perf_copy_attr(struct perf_event_attr __user *uattr,
			  struct perf_event_attr *attr)
{
	u32 size;
	int ret;

	if (!access_ok(VERIFY_WRITE, uattr, PERF_ATTR_SIZE_VER0))
		return -EFAULT;

	/*
	 * zero the full structure, so that a short copy will be nice.
	 */
	memset(attr, 0, sizeof(*attr));

	ret = get_user(size, &uattr->size);
	if (ret)
		return ret;

	if (size > PAGE_SIZE)	/* silly large */
		goto err_size;

	if (!size)		/* abi compat */
		size = PERF_ATTR_SIZE_VER0;

	if (size < PERF_ATTR_SIZE_VER0)
		goto err_size;

	/*
	 * If we're handed a bigger struct than we know of,
	 * ensure all the unknown bits are 0 - i.e. new
	 * user-space does not rely on any kernel feature
	 * extensions we dont know about yet.
	 */
	if (size > sizeof(*attr)) {
		unsigned char __user *addr;
		unsigned char __user *end;
		unsigned char val;

		addr = (void __user *)uattr + sizeof(*attr);
		end  = (void __user *)uattr + size;

		for (; addr < end; addr++) {
			ret = get_user(val, addr);
			if (ret)
				return ret;
			if (val)
				goto err_size;
		}
		size = sizeof(*attr);
	}

	ret = copy_from_user(attr, uattr, size);
	if (ret)
		return -EFAULT;

	if (attr->__reserved_1)
		return -EINVAL;

	if (attr->sample_type & ~(PERF_SAMPLE_MAX-1))
		return -EINVAL;

	if (attr->read_format & ~(PERF_FORMAT_MAX-1))
		return -EINVAL;

	if (attr->sample_type & PERF_SAMPLE_BRANCH_STACK) {
		u64 mask = attr->branch_sample_type;

		/* only using defined bits */
		if (mask & ~(PERF_SAMPLE_BRANCH_MAX-1))
			return -EINVAL;

		/* at least one branch bit must be set */
		if (!(mask & ~PERF_SAMPLE_BRANCH_PLM_ALL))
			return -EINVAL;

		/* kernel level capture: check permissions */
		if ((mask & PERF_SAMPLE_BRANCH_PERM_PLM)
		    && perf_paranoid_kernel() && !capable(CAP_SYS_ADMIN))
			return -EACCES;

		/* propagate priv level, when not set for branch */
		if (!(mask & PERF_SAMPLE_BRANCH_PLM_ALL)) {

			/* exclude_kernel checked on syscall entry */
			if (!attr->exclude_kernel)
				mask |= PERF_SAMPLE_BRANCH_KERNEL;

			if (!attr->exclude_user)
				mask |= PERF_SAMPLE_BRANCH_USER;

			if (!attr->exclude_hv)
				mask |= PERF_SAMPLE_BRANCH_HV;
			/*
			 * adjust user setting (for HW filter setup)
			 */
			attr->branch_sample_type = mask;
		}
	}

	if (attr->sample_type & PERF_SAMPLE_REGS_USER) {
		ret = perf_reg_validate(attr->sample_regs_user);
		if (ret)
			return ret;
	}

	if (attr->sample_type & PERF_SAMPLE_STACK_USER) {
		if (!arch_perf_have_user_stack_dump())
			return -ENOSYS;

		/*
		 * We have __u32 type for the size, but so far
		 * we can only use __u16 as maximum due to the
		 * __u16 sample size limit.
		 */
		if (attr->sample_stack_user >= USHRT_MAX)
			ret = -EINVAL;
		else if (!IS_ALIGNED(attr->sample_stack_user, sizeof(u64)))
			ret = -EINVAL;
	}

out:
	return ret;

err_size:
	put_user(sizeof(*attr), &uattr->size);
	ret = -E2BIG;
	goto out;
}

Project: linux
File: core.c

static inline void perf_event__state_init(struct perf_event *event)
{
	event->state = event->attr.disabled ? PERF_EVENT_STATE_OFF :
					      PERF_EVENT_STATE_INACTIVE;
}

Project: linux
File: core.c

perf_event_alloc(struct perf_event_attr *attr, int cpu,
		 struct task_struct *task,
		 struct perf_event *group_leader,
		 struct perf_event *parent_event,
		 perf_overflow_handler_t overflow_handler,
		 void *context)
{
	struct pmu *pmu;
	struct perf_event *event;
	struct hw_perf_event *hwc;
	long err;

	if ((unsigned)cpu >= nr_cpu_ids) {
		if (!task || cpu != -1)
			return ERR_PTR(-EINVAL);
	}

	event = kzalloc(sizeof(*event), GFP_KERNEL);
	if (!event)
		return ERR_PTR(-ENOMEM);

	/*
	 * Single events are their own group leaders, with an
	 * empty sibling list:
	 */
	if (!group_leader)
		group_leader = event;

	mutex_init(&event->child_mutex);
	INIT_LIST_HEAD(&event->child_list);

	INIT_LIST_HEAD(&event->group_entry);
	INIT_LIST_HEAD(&event->event_entry);
	INIT_LIST_HEAD(&event->sibling_list);
	INIT_LIST_HEAD(&event->rb_entry);

	init_waitqueue_head(&event->waitq);
	init_irq_work(&event->pending, perf_pending_event);

	mutex_init(&event->mmap_mutex);

	atomic_long_set(&event->refcount, 1);
	event->cpu		= cpu;
	event->attr		= *attr;
	event->group_leader	= group_leader;
	event->pmu		= NULL;
	event->oncpu		= -1;

	event->parent		= parent_event;

	event->ns		= get_pid_ns(task_active_pid_ns(current));
	event->id		= atomic64_inc_return(&perf_event_id);

	event->state		= PERF_EVENT_STATE_INACTIVE;

	if (task) {
		event->attach_state = PERF_ATTACH_TASK;

		if (attr->type == PERF_TYPE_TRACEPOINT)
			event->hw.tp_target = task;
#ifdef CONFIG_HAVE_HW_BREAKPOINT
		/*
		 * hw_breakpoint is a bit difficult here..
		 */
		else if (attr->type == PERF_TYPE_BREAKPOINT)
			event->hw.bp_target = task;
#endif
	}

	if (!overflow_handler && parent_event) {
		overflow_handler = parent_event->overflow_handler;
		context = parent_event->overflow_handler_context;
	}

	event->overflow_handler	= overflow_handler;
	event->overflow_handler_context = context;

	perf_event__state_init(event);

	pmu = NULL;

	hwc = &event->hw;
	hwc->sample_period = attr->sample_period;
	if (attr->freq && attr->sample_freq)
		hwc->sample_period = 1;
	hwc->last_period = hwc->sample_period;

	local64_set(&hwc->period_left, hwc->sample_period);

	/*
	 * we currently do not support PERF_FORMAT_GROUP on inherited events
	 */
	if (attr->inherit && (attr->read_format & PERF_FORMAT_GROUP))
		goto done;

	pmu = perf_init_event(event);

done:
	err = 0;
	if (!pmu)
		err = -EINVAL;
	else if (IS_ERR(pmu))
		err = PTR_ERR(pmu);

	if (err) {
		if (event->ns)
			put_pid_ns(event->ns);
		kfree(event);
		return ERR_PTR(err);
	}

	if (!event->parent) {
		if (event->attach_state & PERF_ATTACH_TASK)
			static_key_slow_inc(&perf_sched_events.key);
		if (event->attr.mmap || event->attr.mmap_data)
			atomic_inc(&nr_mmap_events);
		if (event->attr.comm)
			atomic_inc(&nr_comm_events);
		if (event->attr.task)
			atomic_inc(&nr_task_events);
		if (event->attr.sample_type & PERF_SAMPLE_CALLCHAIN) {
			err = get_callchain_buffers();
			if (err) {
				free_event(event);
				return ERR_PTR(err);
			}
		}
		if (has_branch_stack(event)) {
			static_key_slow_inc(&perf_sched_events.key);
			if (!(event->attach_state & PERF_ATTACH_TASK))
				atomic_inc(&per_cpu(perf_branch_stack_events,
						    event->cpu));
		}
	}

	return event;
}

Project: linux
File: core.c

static void perf_event_comm_event(struct perf_comm_event *comm_event)
{
	struct perf_cpu_context *cpuctx;
	struct perf_event_context *ctx;
	char comm[TASK_COMM_LEN];
	unsigned int size;
	struct pmu *pmu;
	int ctxn;

	memset(comm, 0, sizeof(comm));
	strlcpy(comm, comm_event->task->comm, sizeof(comm));
	size = ALIGN(strlen(comm)+1, sizeof(u64));

	comm_event->comm = comm;
	comm_event->comm_size = size;

	comm_event->event_id.header.size = sizeof(comm_event->event_id) + size;
	rcu_read_lock();
	list_for_each_entry_rcu(pmu, &pmus, entry) {
		cpuctx = get_cpu_ptr(pmu->pmu_cpu_context);
		if (cpuctx->unique_pmu != pmu)
			goto next;
		perf_event_comm_ctx(&cpuctx->ctx, comm_event);

		ctxn = pmu->task_ctx_nr;
		if (ctxn < 0)
			goto next;

		ctx = rcu_dereference(current->perf_event_ctxp[ctxn]);
		if (ctx)
			perf_event_comm_ctx(ctx, comm_event);
next:
		put_cpu_ptr(pmu->pmu_cpu_context);
	}
	rcu_read_unlock();
}

Project: linux
File: core.c

static void perf_event_comm_output(struct perf_event *event,
				     struct perf_comm_event *comm_event)
{
	struct perf_output_handle handle;
	struct perf_sample_data sample;
	int size = comm_event->event_id.header.size;
	int ret;

	perf_event_header__init_id(&comm_event->event_id.header, &sample, event);
	ret = perf_output_begin(&handle, event,
				comm_event->event_id.header.size);

	if (ret)
		goto out;

	comm_event->event_id.pid = perf_event_pid(event, comm_event->task);
	comm_event->event_id.tid = perf_event_tid(event, comm_event->task);

	perf_output_put(&handle, comm_event->event_id);
	__output_copy(&handle, comm_event->comm,
				   comm_event->comm_size);

	perf_event__output_id_sample(event, &handle, &sample);

	perf_output_end(&handle);
out:
	comm_event->event_id.header.size = size;
}

Project: linux
File: core.c

static void perf_event_context_sched_in(struct perf_event_context *ctx,
					struct task_struct *task)
{
	struct perf_cpu_context *cpuctx;

	cpuctx = __get_cpu_context(ctx);
	if (cpuctx->task_ctx == ctx)
		return;

	perf_ctx_lock(cpuctx, ctx);
	perf_pmu_disable(ctx->pmu);
	/*
	 * We want to keep the following priority order:
	 * cpu pinned (that don't need to move), task pinned,
	 * cpu flexible, task flexible.
	 */
	cpu_ctx_sched_out(cpuctx, EVENT_FLEXIBLE);

	if (ctx->nr_events)
		cpuctx->task_ctx = ctx;

	perf_event_sched_in(cpuctx, cpuctx->task_ctx, task);

	perf_pmu_enable(ctx->pmu);
	perf_ctx_unlock(cpuctx, ctx);

	/*
	 * Since these rotations are per-cpu, we need to ensure the
	 * cpu-context we got scheduled on is actually rotating.
	 */
	perf_pmu_rotate_start(ctx->pmu);
}

Project: linux
File: core.c

perf_event_create_kernel_counter(struct perf_event_attr *attr, int cpu,
				 struct task_struct *task,
				 perf_overflow_handler_t overflow_handler,
				 void *context)
{
	struct perf_event_context *ctx;
	struct perf_event *event;
	int err;

	/*
	 * Get the target context (task or percpu):
	 */

	event = perf_event_alloc(attr, cpu, task, NULL, NULL,
				 overflow_handler, context);
	if (IS_ERR(event)) {
		err = PTR_ERR(event);
		goto err;
	}

	ctx = find_get_context(event->pmu, task, cpu);
	if (IS_ERR(ctx)) {
		err = PTR_ERR(ctx);
		goto err_free;
	}

	WARN_ON_ONCE(ctx->parent_ctx);
	mutex_lock(&ctx->mutex);
	perf_install_in_context(ctx, event, cpu);
	++ctx->generation;
	perf_unpin_context(ctx);
	mutex_unlock(&ctx->mutex);

	return event;

err_free:
	free_event(event);
err:
	return ERR_PTR(err);
}

Project: linux
File: core.c

static void perf_event_enable_on_exec(struct perf_event_context *ctx)
{
	struct perf_event *event;
	unsigned long flags;
	int enabled = 0;
	int ret;

	local_irq_save(flags);
	if (!ctx || !ctx->nr_events)
		goto out;

	/*
	 * We must ctxsw out cgroup events to avoid conflict
	 * when invoking perf_task_event_sched_in() later on
	 * in this function. Otherwise we end up trying to
	 * ctxswin cgroup events which are already scheduled
	 * in.
	 */
	perf_cgroup_sched_out(current, NULL);

	raw_spin_lock(&ctx->lock);
	task_ctx_sched_out(ctx);

	list_for_each_entry(event, &ctx->event_list, event_entry) {
		ret = event_enable_on_exec(event, ctx);
		if (ret)
			enabled = 1;
	}

	/*
	 * Unclone this context if we enabled any event.
	 */
	if (enabled)
		unclone_ctx(ctx);

	raw_spin_unlock(&ctx->lock);

	/*
	 * Also calls ctxswin for cgroup events, if any:
	 */
	perf_event_context_sched_in(ctx, ctx->task);
out:
	local_irq_restore(flags);
}

Project: linux
File: core.c

static void perf_event_exit_task_context(struct task_struct *child, int ctxn)
{
	struct perf_event *child_event, *tmp;
	struct perf_event_context *child_ctx;
	unsigned long flags;

	if (likely(!child->perf_event_ctxp[ctxn])) {
		perf_event_task(child, NULL, 0);
		return;
	}

	local_irq_save(flags);
	/*
	 * We can't reschedule here because interrupts are disabled,
	 * and either child is current or it is a task that can't be
	 * scheduled, so we are now safe from rescheduling changing
	 * our context.
	 */
	child_ctx = rcu_dereference_raw(child->perf_event_ctxp[ctxn]);

	/*
	 * Take the context lock here so that if find_get_context is
	 * reading child->perf_event_ctxp, we wait until it has
	 * incremented the context's refcount before we do put_ctx below.
	 */
	raw_spin_lock(&child_ctx->lock);
	task_ctx_sched_out(child_ctx);
	child->perf_event_ctxp[ctxn] = NULL;
	/*
	 * If this context is a clone; unclone it so it can't get
	 * swapped to another process while we're removing all
	 * the events from it.
	 */
	unclone_ctx(child_ctx);
	update_context_time(child_ctx);
	raw_spin_unlock_irqrestore(&child_ctx->lock, flags);

	/*
	 * Report the task dead after unscheduling the events so that we
	 * won't get any samples after PERF_RECORD_EXIT. We can however still
	 * get a few PERF_RECORD_READ events.
	 */
	perf_event_task(child, child_ctx, 0);

	/*
	 * We can recurse on the same lock type through:
	 *
	 *   __perf_event_exit_task()
	 *     sync_child_event()
	 *       put_event()
	 *         mutex_lock(&ctx->mutex)
	 *
	 * But since its the parent context it won't be the same instance.
	 */
	mutex_lock(&child_ctx->mutex);

again:
	list_for_each_entry_safe(child_event, tmp, &child_ctx->pinned_groups,
				 group_entry)
		__perf_event_exit_task(child_event, child_ctx, child);

	list_for_each_entry_safe(child_event, tmp, &child_ctx->flexible_groups,
				 group_entry)
		__perf_event_exit_task(child_event, child_ctx, child);

	/*
	 * If the last event was a group event, it will have appended all
	 * its siblings to the list, but we obtained 'tmp' before that which
	 * will still point to the list head terminating the iteration.
	 */
	if (!list_empty(&child_ctx->pinned_groups) ||
	    !list_empty(&child_ctx->flexible_groups))
		goto again;

	mutex_unlock(&child_ctx->mutex);

	put_ctx(child_ctx);
}

Project: linux
File: core.c

static int perf_event_idx_default(struct perf_event *event)
{
	return event->hw.idx + 1;
}

Project: linux
File: core.c

static int perf_event_index(struct perf_event *event)
{
	if (event->hw.state & PERF_HES_STOPPED)
		return 0;

	if (event->state != PERF_EVENT_STATE_ACTIVE)
		return 0;

	return event->pmu->event_idx(event);
}

Project: linux
File: core.c

void __init perf_event_init(void)
{
	int ret;

	idr_init(&pmu_idr);

	perf_event_init_all_cpus();
	init_srcu_struct(&pmus_srcu);
	perf_pmu_register(&perf_swevent, "software", PERF_TYPE_SOFTWARE);
	perf_pmu_register(&perf_cpu_clock, NULL, -1);
	perf_pmu_register(&perf_task_clock, NULL, -1);
	perf_tp_register();
	perf_cpu_notifier(perf_cpu_notify);
	register_reboot_notifier(&perf_reboot_notifier);

	ret = init_hw_breakpoint();
	WARN(ret, "hw_breakpoint initialization failed with: %d", ret);

	/* do not patch jump label more than once per second */
	jump_label_rate_limit(&perf_sched_events, HZ);

	/*
	 * Build time assertion that we keep the data_head at the intended
	 * location.  IOW, validation we got the __reserved[] size right.
	 */
	BUILD_BUG_ON((offsetof(struct perf_event_mmap_page, data_head))
		     != 1024);
}

Project: linux
File: core.c

static void perf_event_mmap_output(struct perf_event *event,
				     struct perf_mmap_event *mmap_event)
{
	struct perf_output_handle handle;
	struct perf_sample_data sample;
	int size = mmap_event->event_id.header.size;
	int ret;

	perf_event_header__init_id(&mmap_event->event_id.header, &sample, event);
	ret = perf_output_begin(&handle, event,
				mmap_event->event_id.header.size);
	if (ret)
		goto out;

	mmap_event->event_id.pid = perf_event_pid(event, current);
	mmap_event->event_id.tid = perf_event_tid(event, current);

	perf_output_put(&handle, mmap_event->event_id);
	__output_copy(&handle, mmap_event->file_name,
				   mmap_event->file_size);

	perf_event__output_id_sample(event, &handle, &sample);

	perf_output_end(&handle);
out:
	mmap_event->event_id.header.size = size;
}

Project: linux
File: core.c

static void perf_event_output(struct perf_event *event,
				struct perf_sample_data *data,
				struct pt_regs *regs)
{
	struct perf_output_handle handle;
	struct perf_event_header header;

	/* protect the callchain buffers */
	rcu_read_lock();

	perf_prepare_sample(&header, data, event, regs);

	if (perf_output_begin(&handle, event, header.size))
		goto exit;

	perf_output_sample(&handle, &header, data, event);

	perf_output_end(&handle);

exit:
	rcu_read_unlock();
}

Project: linux
File: core.c

int perf_event_overflow(struct perf_event *event,
			  struct perf_sample_data *data,
			  struct pt_regs *regs)
{
	return __perf_event_overflow(event, 1, data, regs);
}

Project: linux
File: core.c

perf_event_read_event(struct perf_event *event,
			struct task_struct *task)
{
	struct perf_output_handle handle;
	struct perf_sample_data sample;
	struct perf_read_event read_event = {
		.header = {
			.type = PERF_RECORD_READ,
			.misc = 0,
			.size = sizeof(read_event) + event->read_size,
		},
		.pid = perf_event_pid(event, task),
		.tid = perf_event_tid(event, task),
	};
	int ret;

	perf_event_header__init_id(&read_event.header, &sample, event);
	ret = perf_output_begin(&handle, event, read_event.header.size);
	if (ret)
		return;

	perf_output_put(&handle, read_event);
	perf_output_read(&handle, event);
	perf_event__output_id_sample(event, &handle, &sample);

	perf_output_end(&handle);
}

Project: linux
File: core.c

perf_event_set_output(struct perf_event *event, struct perf_event *output_event)
{
	struct ring_buffer *rb = NULL, *old_rb = NULL;
	int ret = -EINVAL;

	if (!output_event)
		goto set;

	/* don't allow circular references */
	if (event == output_event)
		goto out;

	/*
	 * Don't allow cross-cpu buffers
	 */
	if (output_event->cpu != event->cpu)
		goto out;

	/*
	 * If its not a per-cpu rb, it must be the same task.
	 */
	if (output_event->cpu == -1 && output_event->ctx != event->ctx)
		goto out;

set:
	mutex_lock(&event->mmap_mutex);
	/* Can't redirect output if we've got an active mmap() */
	if (atomic_read(&event->mmap_count))
		goto unlock;

	if (output_event) {
		/* get the rb we want to redirect to */
		rb = ring_buffer_get(output_event);
		if (!rb)
			goto unlock;
	}

	old_rb = event->rb;
	rcu_assign_pointer(event->rb, rb);
	if (old_rb)
		ring_buffer_detach(event, old_rb);
	ret = 0;
unlock:
	mutex_unlock(&event->mmap_mutex);

	if (old_rb)
		ring_buffer_put(old_rb);
out:
	return ret;
}

Project: linux
File: core.c

void perf_event_task_tick(void)
{
	struct list_head *head = &__get_cpu_var(rotation_list);
	struct perf_cpu_context *cpuctx, *tmp;
	struct perf_event_context *ctx;
	int throttled;

	WARN_ON(!irqs_disabled());

	__this_cpu_inc(perf_throttled_seq);
	throttled = __this_cpu_xchg(perf_throttled_count, 0);

	list_for_each_entry_safe(cpuctx, tmp, head, rotation_list) {
		ctx = &cpuctx->ctx;
		perf_adjust_freq_unthr_context(ctx, throttled);

		ctx = cpuctx->task_ctx;
		if (ctx)
			perf_adjust_freq_unthr_context(ctx, throttled);

		if (cpuctx->jiffies_interval == 1 ||
				!(jiffies % cpuctx->jiffies_interval))
			perf_rotate_context(cpuctx);
	}
}

Project: linux
File: core.c

void perf_event_update_userpage(struct perf_event *event)
{
	struct perf_event_mmap_page *userpg;
	struct ring_buffer *rb;
	u64 enabled, running, now;

	rcu_read_lock();
	/*
	 * compute total_time_enabled, total_time_running
	 * based on snapshot values taken when the event
	 * was last scheduled in.
	 *
	 * we cannot simply called update_context_time()
	 * because of locking issue as we can be called in
	 * NMI context
	 */
	calc_timer_values(event, &now, &enabled, &running);
	rb = rcu_dereference(event->rb);
	if (!rb)
		goto unlock;

	userpg = rb->user_page;

	/*
	 * Disable preemption so as to not let the corresponding user-space
	 * spin too long if we get preempted.
	 */
	preempt_disable();
	++userpg->lock;
	barrier();
	userpg->index = perf_event_index(event);
	userpg->offset = perf_event_count(event);
	if (userpg->index)
		userpg->offset -= local64_read(&event->hw.prev_count);

	userpg->time_enabled = enabled +
			atomic64_read(&event->child_total_time_enabled);

	userpg->time_running = running +
			atomic64_read(&event->child_total_time_running);

	arch_perf_update_userpage(userpg, now);

	barrier();
	++userpg->lock;
	preempt_enable();
unlock:
	rcu_read_unlock();
}

Project: linux
File: core.c

void perf_event_wakeup(struct perf_event *event)
{
	ring_buffer_wakeup(event);

	if (event->pending_kill) {
		kill_fasync(&event->fasync, SIGIO, event->pending_kill);
		event->pending_kill = 0;
	}
}

Project: linux
File: core.c

static int perf_fasync(int fd, struct file *filp, int on)
{
	struct inode *inode = file_inode(filp);
	struct perf_event *event = filp->private_data;
	int retval;

	mutex_lock(&inode->i_mutex);
	retval = fasync_helper(fd, filp, on, &event->fasync);
	mutex_unlock(&inode->i_mutex);

	if (retval < 0)
		return retval;

	return 0;
}

Project: linux
File: core.c

static void perf_free_event(struct perf_event *event,
			    struct perf_event_context *ctx)
{
	struct perf_event *parent = event->parent;

	if (WARN_ON_ONCE(!parent))
		return;

	mutex_lock(&parent->child_mutex);
	list_del_init(&event->child_list);
	mutex_unlock(&parent->child_mutex);

	put_event(parent);

	perf_group_detach(event);
	list_del_event(event, ctx);
	free_event(event);
}

Project: linux
File: core.c

struct pmu *perf_init_event(struct perf_event *event)
{
	struct pmu *pmu = NULL;
	int idx;
	int ret;

	idx = srcu_read_lock(&pmus_srcu);

	rcu_read_lock();
	pmu = idr_find(&pmu_idr, event->attr.type);
	rcu_read_unlock();
	if (pmu) {
		event->pmu = pmu;
		ret = pmu->event_init(event);
		if (ret)
			pmu = ERR_PTR(ret);
		goto unlock;
	}

	list_for_each_entry_rcu(pmu, &pmus, entry) {
		event->pmu = pmu;
		ret = pmu->event_init(event);
		if (!ret)
			goto unlock;

		if (ret != -ENOENT) {
			pmu = ERR_PTR(ret);
			goto unlock;
		}
	}
	pmu = ERR_PTR(-ENOENT);
unlock:
	srcu_read_unlock(&pmus_srcu, idx);

	return pmu;
}

Project: linux
File: core.c

perf_install_in_context(struct perf_event_context *ctx,
			struct perf_event *event,
			int cpu)
{
	struct task_struct *task = ctx->task;

	lockdep_assert_held(&ctx->mutex);

	event->ctx = ctx;
	if (event->cpu != -1)
		event->cpu = cpu;

	if (!task) {
		/*
		 * Per cpu events are installed via an smp call and
		 * the install is always successful.
		 */
		cpu_function_call(cpu, __perf_install_in_context, event);
		return;
	}

retry:
	if (!task_function_call(task, __perf_install_in_context, event))
		return;

	raw_spin_lock_irq(&ctx->lock);
	/*
	 * If we failed to find a running task, but find the context active now
	 * that we've acquired the ctx->lock, retry.
	 */
	if (ctx->is_active) {
		raw_spin_unlock_irq(&ctx->lock);
		goto retry;
	}

	/*
	 * Since the task isn't running, its safe to add the event, us holding
	 * the ctx->lock ensures the task won't get scheduled in.
	 */
	add_event_to_ctx(event, ctx);
	raw_spin_unlock_irq(&ctx->lock);
}

Project: linux
File: core.c

static int perf_mmap(struct file *file, struct vm_area_struct *vma)
{
	struct perf_event *event = file->private_data;
	unsigned long user_locked, user_lock_limit;
	struct user_struct *user = current_user();
	unsigned long locked, lock_limit;
	struct ring_buffer *rb;
	unsigned long vma_size;
	unsigned long nr_pages;
	long user_extra, extra;
	int ret = 0, flags = 0;

	/*
	 * Don't allow mmap() of inherited per-task counters. This would
	 * create a performance issue due to all children writing to the
	 * same rb.
	 */
	if (event->cpu == -1 && event->attr.inherit)
		return -EINVAL;

	if (!(vma->vm_flags & VM_SHARED))
		return -EINVAL;

	vma_size = vma->vm_end - vma->vm_start;
	nr_pages = (vma_size / PAGE_SIZE) - 1;

	/*
	 * If we have rb pages ensure they're a power-of-two number, so we
	 * can do bitmasks instead of modulo.
	 */
	if (nr_pages != 0 && !is_power_of_2(nr_pages))
		return -EINVAL;

	if (vma_size != PAGE_SIZE * (1 + nr_pages))
		return -EINVAL;

	if (vma->vm_pgoff != 0)
		return -EINVAL;

	WARN_ON_ONCE(event->ctx->parent_ctx);
	mutex_lock(&event->mmap_mutex);
	if (event->rb) {
		if (event->rb->nr_pages == nr_pages)
			atomic_inc(&event->rb->refcount);
		else
			ret = -EINVAL;
		goto unlock;
	}

	user_extra = nr_pages + 1;
	user_lock_limit = sysctl_perf_event_mlock >> (PAGE_SHIFT - 10);

	/*
	 * Increase the limit linearly with more CPUs:
	 */
	user_lock_limit *= num_online_cpus();

	user_locked = atomic_long_read(&user->locked_vm) + user_extra;

	extra = 0;
	if (user_locked > user_lock_limit)
		extra = user_locked - user_lock_limit;

	lock_limit = rlimit(RLIMIT_MEMLOCK);
	lock_limit >>= PAGE_SHIFT;
	locked = vma->vm_mm->pinned_vm + extra;

	if ((locked > lock_limit) && perf_paranoid_tracepoint_raw() &&
		!capable(CAP_IPC_LOCK)) {
		ret = -EPERM;
		goto unlock;
	}

	WARN_ON(event->rb);

	if (vma->vm_flags & VM_WRITE)
		flags |= RING_BUFFER_WRITABLE;

	rb = rb_alloc(nr_pages, 
		event->attr.watermark ? event->attr.wakeup_watermark : 0,
		event->cpu, flags);

	if (!rb) {
		ret = -ENOMEM;
		goto unlock;
	}
	rcu_assign_pointer(event->rb, rb);

	atomic_long_add(user_extra, &user->locked_vm);
	event->mmap_locked = extra;
	event->mmap_user = get_current_user();
	vma->vm_mm->pinned_vm += event->mmap_locked;

	perf_event_update_userpage(event);

unlock:
	if (!ret)
		atomic_inc(&event->mmap_count);
	mutex_unlock(&event->mmap_mutex);

	vma->vm_flags |= VM_DONTEXPAND | VM_DONTDUMP;
	vma->vm_ops = &perf_mmap_vmops;

	return ret;
}

Project: linux
File: core.c

static void perf_mmap_close(struct vm_area_struct *vma)
{
	struct perf_event *event = vma->vm_file->private_data;

	if (atomic_dec_and_mutex_lock(&event->mmap_count, &event->mmap_mutex)) {
		unsigned long size = perf_data_size(event->rb);
		struct user_struct *user = event->mmap_user;
		struct ring_buffer *rb = event->rb;

		atomic_long_sub((size >> PAGE_SHIFT) + 1, &user->locked_vm);
		vma->vm_mm->pinned_vm -= event->mmap_locked;
		rcu_assign_pointer(event->rb, NULL);
		ring_buffer_detach(event, rb);
		mutex_unlock(&event->mmap_mutex);

		ring_buffer_put(rb);
		free_uid(user);
	}
}

Project: linux
File: core.c

static void perf_output_read(struct perf_output_handle *handle,
			     struct perf_event *event)
{
	u64 enabled = 0, running = 0, now;
	u64 read_format = event->attr.read_format;

	/*
	 * compute total_time_enabled, total_time_running
	 * based on snapshot values taken when the event
	 * was last scheduled in.
	 *
	 * we cannot simply called update_context_time()
	 * because of locking issue as we are called in
	 * NMI context
	 */
	if (read_format & PERF_FORMAT_TOTAL_TIMES)
		calc_timer_values(event, &now, &enabled, &running);

	if (event->attr.read_format & PERF_FORMAT_GROUP)
		perf_output_read_group(handle, event, enabled, running);
	else
		perf_output_read_one(handle, event, enabled, running);
}

Project: linux
File: core.c

void perf_output_sample(struct perf_output_handle *handle,
			struct perf_event_header *header,
			struct perf_sample_data *data,
			struct perf_event *event)
{
	u64 sample_type = data->type;

	perf_output_put(handle, *header);

	if (sample_type & PERF_SAMPLE_IP)
		perf_output_put(handle, data->ip);

	if (sample_type & PERF_SAMPLE_TID)
		perf_output_put(handle, data->tid_entry);

	if (sample_type & PERF_SAMPLE_TIME)
		perf_output_put(handle, data->time);

	if (sample_type & PERF_SAMPLE_ADDR)
		perf_output_put(handle, data->addr);

	if (sample_type & PERF_SAMPLE_ID)
		perf_output_put(handle, data->id);

	if (sample_type & PERF_SAMPLE_STREAM_ID)
		perf_output_put(handle, data->stream_id);

	if (sample_type & PERF_SAMPLE_CPU)
		perf_output_put(handle, data->cpu_entry);

	if (sample_type & PERF_SAMPLE_PERIOD)
		perf_output_put(handle, data->period);

	if (sample_type & PERF_SAMPLE_READ)
		perf_output_read(handle, event);

	if (sample_type & PERF_SAMPLE_CALLCHAIN) {
		if (data->callchain) {
			int size = 1;

			if (data->callchain)
				size += data->callchain->nr;

			size *= sizeof(u64);

			__output_copy(handle, data->callchain, size);
		} else {
			u64 nr = 0;
			perf_output_put(handle, nr);
		}
	}

	if (sample_type & PERF_SAMPLE_RAW) {
		if (data->raw) {
			perf_output_put(handle, data->raw->size);
			__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);
		}
	}

	if (!event->attr.watermark) {
		int wakeup_events = event->attr.wakeup_events;

		if (wakeup_events) {
			struct ring_buffer *rb = handle->rb;
			int events = local_inc_return(&rb->events);

			if (events >= wakeup_events) {
				local_sub(wakeup_events, &rb->events);
				local_inc(&rb->wakeup);
			}
		}
	}

	if (sample_type & PERF_SAMPLE_BRANCH_STACK) {
		if (data->br_stack) {
			size_t size;

			size = data->br_stack->nr
			     * sizeof(struct perf_branch_entry);

			perf_output_put(handle, data->br_stack->nr);
			perf_output_copy(handle, data->br_stack->entries, size);
		} else {
			/*
			 * we always store at least the value of nr
			 */
			u64 nr = 0;
			perf_output_put(handle, nr);
		}
	}

	if (sample_type & PERF_SAMPLE_REGS_USER) {
		u64 abi = data->regs_user.abi;

		/*
		 * If there are no regs to dump, notice it through
		 * first u64 being zero (PERF_SAMPLE_REGS_ABI_NONE).
		 */
		perf_output_put(handle, abi);

		if (abi) {
			u64 mask = event->attr.sample_regs_user;
			perf_output_sample_regs(handle,
						data->regs_user.regs,
						mask);
		}
	}

	if (sample_type & PERF_SAMPLE_STACK_USER)
		perf_output_sample_ustack(handle,
					  data->stack_user_size,
					  data->regs_user.regs);
}

Project: linux
File: core.c

perf_output_sample_regs(struct perf_output_handle *handle,
			struct pt_regs *regs, u64 mask)
{
	int bit;

	for_each_set_bit(bit, (const unsigned long *) &mask,
			 sizeof(mask) * BITS_PER_BYTE) {
		u64 val;

		val = perf_reg_value(regs, bit);
		perf_output_put(handle, val);
	}
}

Project: linux
File: core.c

perf_output_sample_ustack(struct perf_output_handle *handle, u64 dump_size,
			  struct pt_regs *regs)
{
	/* Case of a kernel thread, nothing to dump */
	if (!regs) {
		u64 size = 0;
		perf_output_put(handle, size);
	} else {
		unsigned long sp;
		unsigned int rem;
		u64 dyn_size;

		/*
		 * We dump:
		 * static size
		 *   - the size requested by user or the best one we can fit
		 *     in to the sample max size
		 * data
		 *   - user stack dump data
		 * dynamic size
		 *   - the actual dumped size
		 */

		/* Static size. */
		perf_output_put(handle, dump_size);

		/* Data. */
		sp = perf_user_stack_pointer(regs);
		rem = __output_copy_user(handle, (void *) sp, dump_size);
		dyn_size = dump_size - rem;

		perf_output_skip(handle, rem);

		/* Dynamic size. */
		perf_output_put(handle, dyn_size);
	}
}

Project: linux
File: core.c

void perf_pmu_migrate_context(struct pmu *pmu, int src_cpu, int dst_cpu)
{
	struct perf_event_context *src_ctx;
	struct perf_event_context *dst_ctx;
	struct perf_event *event, *tmp;
	LIST_HEAD(events);

	src_ctx = &per_cpu_ptr(pmu->pmu_cpu_context, src_cpu)->ctx;
	dst_ctx = &per_cpu_ptr(pmu->pmu_cpu_context, dst_cpu)->ctx;

	mutex_lock(&src_ctx->mutex);
	list_for_each_entry_safe(event, tmp, &src_ctx->event_list,
				 event_entry) {
		perf_remove_from_context(event);
		put_ctx(src_ctx);
		list_add(&event->event_entry, &events);
	}
	mutex_unlock(&src_ctx->mutex);

	synchronize_rcu();

	mutex_lock(&dst_ctx->mutex);
	list_for_each_entry_safe(event, tmp, &events, event_entry) {
		list_del(&event->event_entry);
		if (event->state >= PERF_EVENT_STATE_OFF)
			event->state = PERF_EVENT_STATE_INACTIVE;
		perf_install_in_context(dst_ctx, event, dst_cpu);
		get_ctx(dst_ctx);
	}
	mutex_unlock(&dst_ctx->mutex);
}

Project: linux
File: core.c

int perf_pmu_register(struct pmu *pmu, char *name, int type)
{
	int cpu, ret;

	mutex_lock(&pmus_lock);
	ret = -ENOMEM;
	pmu->pmu_disable_count = alloc_percpu(int);
	if (!pmu->pmu_disable_count)
		goto unlock;

	pmu->type = -1;
	if (!name)
		goto skip_type;
	pmu->name = name;

	if (type < 0) {
		type = idr_alloc(&pmu_idr, pmu, PERF_TYPE_MAX, 0, GFP_KERNEL);
		if (type < 0) {
			ret = type;
			goto free_pdc;
		}
	}
	pmu->type = type;

	if (pmu_bus_running) {
		ret = pmu_dev_alloc(pmu);
		if (ret)
			goto free_idr;
	}

skip_type:
	pmu->pmu_cpu_context = find_pmu_context(pmu->task_ctx_nr);
	if (pmu->pmu_cpu_context)
		goto got_cpu_context;

	ret = -ENOMEM;
	pmu->pmu_cpu_context = alloc_percpu(struct perf_cpu_context);
	if (!pmu->pmu_cpu_context)
		goto free_dev;

	for_each_possible_cpu(cpu) {
		struct perf_cpu_context *cpuctx;

		cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
		__perf_event_init_context(&cpuctx->ctx);
		lockdep_set_class(&cpuctx->ctx.mutex, &cpuctx_mutex);
		lockdep_set_class(&cpuctx->ctx.lock, &cpuctx_lock);
		cpuctx->ctx.type = cpu_context;
		cpuctx->ctx.pmu = pmu;
		cpuctx->jiffies_interval = 1;
		INIT_LIST_HEAD(&cpuctx->rotation_list);
		cpuctx->unique_pmu = pmu;
	}

got_cpu_context:
	if (!pmu->start_txn) {
		if (pmu->pmu_enable) {
			/*
			 * If we have pmu_enable/pmu_disable calls, install
			 * transaction stubs that use that to try and batch
			 * hardware accesses.
			 */
			pmu->start_txn  = perf_pmu_start_txn;
			pmu->commit_txn = perf_pmu_commit_txn;
			pmu->cancel_txn = perf_pmu_cancel_txn;
		} else {
			pmu->start_txn  = perf_pmu_nop_void;
			pmu->commit_txn = perf_pmu_nop_int;
			pmu->cancel_txn = perf_pmu_nop_void;
		}
	}

	if (!pmu->pmu_enable) {
		pmu->pmu_enable  = perf_pmu_nop_void;
		pmu->pmu_disable = perf_pmu_nop_void;
	}

	if (!pmu->event_idx)
		pmu->event_idx = perf_event_idx_default;

	list_add_rcu(&pmu->entry, &pmus);
	ret = 0;
unlock:
	mutex_unlock(&pmus_lock);

	return ret;

free_dev:
	device_del(pmu->dev);
	put_device(pmu->dev);

free_idr:
	if (pmu->type >= PERF_TYPE_MAX)
		idr_remove(&pmu_idr, pmu->type);

free_pdc:
	free_percpu(pmu->pmu_disable_count);
	goto unlock;
}

Project: linux
File: core.c

static unsigned int perf_poll(struct file *file, poll_table *wait)
{
	struct perf_event *event = file->private_data;
	struct ring_buffer *rb;
	unsigned int events = POLL_HUP;

	/*
	 * Race between perf_event_set_output() and perf_poll(): perf_poll()
	 * grabs the rb reference but perf_event_set_output() overrides it.
	 * Here is the timeline for two threads T1, T2:
	 * t0: T1, rb = rcu_dereference(event->rb)
	 * t1: T2, old_rb = event->rb
	 * t2: T2, event->rb = new rb
	 * t3: T2, ring_buffer_detach(old_rb)
	 * t4: T1, ring_buffer_attach(rb1)
	 * t5: T1, poll_wait(event->waitq)
	 *
	 * To avoid this problem, we grab mmap_mutex in perf_poll()
	 * thereby ensuring that the assignment of the new ring buffer
	 * and the detachment of the old buffer appear atomic to perf_poll()
	 */
	mutex_lock(&event->mmap_mutex);

	rcu_read_lock();
	rb = rcu_dereference(event->rb);
	if (rb) {
		ring_buffer_attach(event, rb);
		events = atomic_xchg(&rb->poll, 0);
	}
	rcu_read_unlock();

	mutex_unlock(&event->mmap_mutex);

	poll_wait(file, &event->waitq, wait);

	return events;
}

Project: linux
File: core.c

void perf_prepare_sample(struct perf_event_header *header,
			 struct perf_sample_data *data,
			 struct perf_event *event,
			 struct pt_regs *regs)
{
	u64 sample_type = event->attr.sample_type;

	header->type = PERF_RECORD_SAMPLE;
	header->size = sizeof(*header) + event->header_size;

	header->misc = 0;
	header->misc |= perf_misc_flags(regs);

	__perf_event_header__init_id(header, data, event);

	if (sample_type & PERF_SAMPLE_IP)
		data->ip = perf_instruction_pointer(regs);

	if (sample_type & PERF_SAMPLE_CALLCHAIN) {
		int size = 1;

		data->callchain = perf_callchain(event, regs);

		if (data->callchain)
			size += data->callchain->nr;

		header->size += size * sizeof(u64);
	}

	if (sample_type & PERF_SAMPLE_RAW) {
		int size = sizeof(u32);

		if (data->raw)
			size += data->raw->size;
		else
			size += sizeof(u32);

		WARN_ON_ONCE(size & (sizeof(u64)-1));
		header->size += size;
	}

	if (sample_type & PERF_SAMPLE_BRANCH_STACK) {
		int size = sizeof(u64); /* nr */
		if (data->br_stack) {
			size += data->br_stack->nr
			      * sizeof(struct perf_branch_entry);
		}
		header->size += size;
	}

	if (sample_type & PERF_SAMPLE_REGS_USER) {
		/* regs dump ABI info */
		int size = sizeof(u64);

		perf_sample_regs_user(&data->regs_user, regs);

		if (data->regs_user.regs) {
			u64 mask = event->attr.sample_regs_user;
			size += hweight64(mask) * sizeof(u64);
		}

		header->size += size;
	}

	if (sample_type & PERF_SAMPLE_STACK_USER) {
		/*
		 * Either we need PERF_SAMPLE_STACK_USER bit to be allways
		 * processed as the last one or have additional check added
		 * in case new sample type is added, because we could eat
		 * up the rest of the sample size.
		 */
		struct perf_regs_user *uregs = &data->regs_user;
		u16 stack_size = event->attr.sample_stack_user;
		u16 size = sizeof(u64);

		if (!uregs->abi)
			perf_sample_regs_user(uregs, regs);

		stack_size = perf_sample_ustack_size(stack_size, header->size,
						     uregs->regs);

		/*
		 * If there is something to dump, add space for the dump
		 * itself and for the field that tells the dynamic size,
		 * which is how many have been actually dumped.
		 */
		if (stack_size)
			size += sizeof(u64) + stack_size;

		data->stack_user_size = stack_size;
		header->size += size;
	}
}

Project: linux
File: core.c

static int perf_release(struct inode *inode, struct file *file)
{
	put_event(file->private_data);
	return 0;
}

Project: linux
File: core.c

static void perf_rotate_context(struct perf_cpu_context *cpuctx)
{
	struct perf_event_context *ctx = NULL;
	int rotate = 0, remove = 1;

	if (cpuctx->ctx.nr_events) {
		remove = 0;
		if (cpuctx->ctx.nr_events != cpuctx->ctx.nr_active)
			rotate = 1;
	}

	ctx = cpuctx->task_ctx;
	if (ctx && ctx->nr_events) {
		remove = 0;
		if (ctx->nr_events != ctx->nr_active)
			rotate = 1;
	}

	if (!rotate)
		goto done;

	perf_ctx_lock(cpuctx, cpuctx->task_ctx);
	perf_pmu_disable(cpuctx->ctx.pmu);

	cpu_ctx_sched_out(cpuctx, EVENT_FLEXIBLE);
	if (ctx)
		ctx_sched_out(ctx, cpuctx, EVENT_FLEXIBLE);

	rotate_ctx(&cpuctx->ctx);
	if (ctx)
		rotate_ctx(ctx);

	perf_event_sched_in(cpuctx, ctx, current);

	perf_pmu_enable(cpuctx->ctx.pmu);
	perf_ctx_unlock(cpuctx, cpuctx->task_ctx);
done:
	if (remove)
		list_del_init(&cpuctx->rotation_list);
}

Project: linux
File: core.c

static void perf_sample_regs_user(struct perf_regs_user *regs_user,
				  struct pt_regs *regs)
{
	if (!user_mode(regs)) {
		if (current->mm)
			regs = task_pt_regs(current);
		else
			regs = NULL;
	}

	if (regs) {
		regs_user->regs = regs;
		regs_user->abi  = perf_reg_abi(current);
	}
}

Project: linux
File: core.c

perf_sample_ustack_size(u16 stack_size, u16 header_size,
			struct pt_regs *regs)
{
	u64 task_size;

	/* No regs, no stack pointer, no dump. */
	if (!regs)
		return 0;

	/*
	 * Check if we fit in with the requested stack size into the:
	 * - TASK_SIZE
	 *   If we don't, we limit the size to the TASK_SIZE.
	 *
	 * - remaining sample size
	 *   If we don't, we customize the stack size to
	 *   fit in to the remaining sample size.
	 */

	task_size  = min((u64) USHRT_MAX, perf_ustack_task_size(regs));
	stack_size = min(stack_size, (u16) task_size);

	/* Current header size plus static size and dynamic size. */
	header_size += 2 * sizeof(u64);

	/* Do we fit in with the current stack dump size? */
	if ((u16) (header_size + stack_size) < header_size) {
		/*
		 * If we overflow the maximum size for the sample,
		 * we customize the stack dump size to fit in.
		 */
		stack_size = USHRT_MAX - header_size - sizeof(u64);
		stack_size = round_up(stack_size, sizeof(u64));
	}

	return stack_size;
}

Project: linux
File: core.c

static void perf_swevent_event(struct perf_event *event, u64 nr,
			       struct perf_sample_data *data,
			       struct pt_regs *regs)
{
	struct hw_perf_event *hwc = &event->hw;

	local64_add(nr, &event->count);

	if (!regs)
		return;

	if (!is_sampling_event(event))
		return;

	if ((event->attr.sample_type & PERF_SAMPLE_PERIOD) && !event->attr.freq) {
		data->period = nr;
		return perf_swevent_overflow(event, 1, data, regs);
	} else
		data->period = event->hw.last_period;

	if (nr == 1 && hwc->sample_period == 1 && !event->attr.freq)
		return perf_swevent_overflow(event, 1, data, regs);

	if (local64_add_negative(nr, &hwc->period_left))
		return;

	perf_swevent_overflow(event, 0, data, regs);
}

Project: linux
File: core.c

static int perf_swevent_event_idx(struct perf_event *event)
{
	return 0;
}

Project: linux
File: core.c

static enum hrtimer_restart perf_swevent_hrtimer(struct hrtimer *hrtimer)
{
	enum hrtimer_restart ret = HRTIMER_RESTART;
	struct perf_sample_data data;
	struct pt_regs *regs;
	struct perf_event *event;
	u64 period;

	event = container_of(hrtimer, struct perf_event, hw.hrtimer);

	if (event->state != PERF_EVENT_STATE_ACTIVE)
		return HRTIMER_NORESTART;

	event->pmu->read(event);

	perf_sample_data_init(&data, 0, event->hw.last_period);
	regs = get_irq_regs();

	if (regs && !perf_exclude_event(event, regs)) {
		if (!(event->attr.exclude_idle && is_idle_task(current)))
			if (__perf_event_overflow(event, 1, &data, regs))
				ret = HRTIMER_NORESTART;
	}

	period = max_t(u64, 10000, event->hw.sample_period);
	hrtimer_forward_now(hrtimer, ns_to_ktime(period));

	return ret;
}

Project: linux
File: core.c

static void perf_swevent_init_hrtimer(struct perf_event *event)
{
	struct hw_perf_event *hwc = &event->hw;

	if (!is_sampling_event(event))
		return;

	hrtimer_init(&hwc->hrtimer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
	hwc->hrtimer.function = perf_swevent_hrtimer;

	/*
	 * Since hrtimers have a fixed rate, we can do a static freq->period
	 * mapping and avoid the whole period adjust feedback stuff.
	 */
	if (event->attr.freq) {
		long freq = event->attr.sample_freq;

		event->attr.sample_period = NSEC_PER_SEC / freq;
		hwc->sample_period = event->attr.sample_period;
		local64_set(&hwc->period_left, hwc->sample_period);
		hwc->last_period = hwc->sample_period;
		event->attr.freq = 0;
	}
}

Project: linux
File: core.c

static void perf_swevent_overflow(struct perf_event *event, u64 overflow,
				    struct perf_sample_data *data,
				    struct pt_regs *regs)
{
	struct hw_perf_event *hwc = &event->hw;
	int throttle = 0;

	if (!overflow)
		overflow = perf_swevent_set_period(event);

	if (hwc->interrupts == MAX_INTERRUPTS)
		return;

	for (; overflow; overflow--) {
		if (__perf_event_overflow(event, throttle,
					    data, regs)) {
			/*
			 * We inhibit the overflow from happening when
			 * hwc->interrupts == MAX_INTERRUPTS.
			 */
			break;
		}
		throttle = 1;
	}
}

Project: linux
File: core.c

void perf_tp_event(u64 addr, u64 count, void *record, int entry_size,
		   struct pt_regs *regs, struct hlist_head *head, int rctx,
		   struct task_struct *task)
{
	struct perf_sample_data data;
	struct perf_event *event;

	struct perf_raw_record raw = {
		.size = entry_size,
		.data = record,
	};

	perf_sample_data_init(&data, addr, 0);
	data.raw = &raw;

	hlist_for_each_entry_rcu(event, head, hlist_entry) {
		if (perf_tp_event_match(event, &data, regs))
			perf_swevent_event(event, count, &data, regs);
	}

	/*
	 * If we got specified a target task, also iterate its context and
	 * deliver this event there too.
	 */
	if (task && task != current) {
		struct perf_event_context *ctx;
		struct trace_entry *entry = record;

		rcu_read_lock();
		ctx = rcu_dereference(task->perf_event_ctxp[perf_sw_context]);
		if (!ctx)
			goto unlock;

		list_for_each_entry_rcu(event, &ctx->event_list, event_entry) {
			if (event->attr.type != PERF_TYPE_TRACEPOINT)
				continue;
			if (event->attr.config != entry->type)
				continue;
			if (perf_tp_event_match(event, &data, regs))
				perf_swevent_event(event, count, &data, regs);
		}
unlock:
		rcu_read_unlock();
	}

	perf_swevent_put_recursion_context(rctx);
}

Project: linux
File: core.c

static int perf_tp_event_init(struct perf_event *event)
{
	int err;

	if (event->attr.type != PERF_TYPE_TRACEPOINT)
		return -ENOENT;

	/*
	 * no branch sampling for tracepoint events
	 */
	if (has_branch_stack(event))
		return -EOPNOTSUPP;

	err = perf_trace_init(event);
	if (err)
		return err;

	event->destroy = tp_perf_event_destroy;

	return 0;
}

Project: linux
File: core.c

static inline bool perf_tryget_cgroup(struct perf_event *event)
{
	return css_tryget(&event->cgrp->css);
}

Project: linux
File: core.c

static u64 perf_ustack_task_size(struct pt_regs *regs)
{
	unsigned long addr = perf_user_stack_pointer(regs);

	if (!addr || addr >= TASK_SIZE)
		return 0;

	return TASK_SIZE - addr;
}

Project: linux
File: core.c

static int pmu_dev_alloc(struct pmu *pmu)
{
	int ret = -ENOMEM;

	pmu->dev = kzalloc(sizeof(struct device), GFP_KERNEL);
	if (!pmu->dev)
		goto out;

	pmu->dev->groups = pmu->attr_groups;
	device_initialize(pmu->dev);
	ret = dev_set_name(pmu->dev, "%s", pmu->name);
	if (ret)
		goto free_dev;

	dev_set_drvdata(pmu->dev, pmu);
	pmu->dev->bus = &pmu_bus;
	pmu->dev->release = pmu_dev_release;
	ret = device_add(pmu->dev);
	if (ret)
		goto free_dev;

out:
	return ret;

free_dev:
	put_device(pmu->dev);
	goto out;
}

Project: linux
File: core.c

static void put_event(struct perf_event *event)
{
	struct task_struct *owner;

	if (!atomic_long_dec_and_test(&event->refcount))
		return;

	rcu_read_lock();
	owner = ACCESS_ONCE(event->owner);
	/*
	 * Matches the smp_wmb() in perf_event_exit_task(). If we observe
	 * !owner it means the list deletion is complete and we can indeed
	 * free this event, otherwise we need to serialize on
	 * owner->perf_event_mutex.
	 */
	smp_read_barrier_depends();
	if (owner) {
		/*
		 * Since delayed_put_task_struct() also drops the last
		 * task reference we can safely take a new reference
		 * while holding the rcu_read_lock().
		 */
		get_task_struct(owner);
	}
	rcu_read_unlock();

	if (owner) {
		mutex_lock(&owner->perf_event_mutex);
		/*
		 * We have to re-check the event->owner field, if it is cleared
		 * we raced with perf_event_exit_task(), acquiring the mutex
		 * ensured they're done, and we can proceed with freeing the
		 * event.
		 */
		if (event->owner)
			list_del_init(&event->owner_entry);
		mutex_unlock(&owner->perf_event_mutex);
		put_task_struct(owner);
	}

	perf_event_release_kernel(event);
}

Project: linux
File: core.c

static void ring_buffer_attach(struct perf_event *event,
			       struct ring_buffer *rb)
{
	unsigned long flags;

	if (!list_empty(&event->rb_entry))
		return;

	spin_lock_irqsave(&rb->event_lock, flags);
	if (!list_empty(&event->rb_entry))
		goto unlock;

	list_add(&event->rb_entry, &rb->event_list);
unlock:
	spin_unlock_irqrestore(&rb->event_lock, flags);
}

Project: linux
File: core.c

static void ring_buffer_put(struct ring_buffer *rb)
{
	struct perf_event *event, *n;
	unsigned long flags;

	if (!atomic_dec_and_test(&rb->refcount))
		return;

	spin_lock_irqsave(&rb->event_lock, flags);
	list_for_each_entry_safe(event, n, &rb->event_list, rb_entry) {
		list_del_init(&event->rb_entry);
		wake_up_all(&event->waitq);
	}
	spin_unlock_irqrestore(&rb->event_lock, flags);

	call_rcu(&rb->rcu_head, rb_free_rcu);
}

Project: linux
File: core.c

static void ring_buffer_wakeup(struct perf_event *event)
{
	struct ring_buffer *rb;

	rcu_read_lock();
	rb = rcu_dereference(event->rb);
	if (!rb)
		goto unlock;

	list_for_each_entry_rcu(event, &rb->event_list, rb_entry)
		wake_up_all(&event->waitq);

unlock:
	rcu_read_unlock();
}

Project: linux
File: core.c

static void sw_perf_event_destroy(struct perf_event *event)
{
	u64 event_id = event->attr.config;

	WARN_ON(event->parent);

	static_key_slow_dec(&perf_swevent_enabled[event_id]);
	swevent_hlist_put(event);
}

Project: linux
File: core.c

static void sync_child_event(struct perf_event *child_event,
			       struct task_struct *child)
{
	struct perf_event *parent_event = child_event->parent;
	u64 child_val;

	if (child_event->attr.inherit_stat)
		perf_event_read_event(child_event, child);

	child_val = perf_event_count(child_event);

	/*
	 * Add back the child's count to the parent's count:
	 */
	atomic64_add(child_val, &parent_event->child_count);
	atomic64_add(child_event->total_time_enabled,
		     &parent_event->child_total_time_enabled);
	atomic64_add(child_event->total_time_running,
		     &parent_event->child_total_time_running);

	/*
	 * Remove this event from the parent's list
	 */
	WARN_ON_ONCE(parent_event->ctx->parent_ctx);
	mutex_lock(&parent_event->child_mutex);
	list_del_init(&child_event->child_list);
	mutex_unlock(&parent_event->child_mutex);

	/*
	 * Release the parent event, if this was the last
	 * reference to it.
	 */
	put_event(parent_event);
}

Project: linux
File: core.c

static int task_clock_event_init(struct perf_event *event)
{
	if (event->attr.type != PERF_TYPE_SOFTWARE)
		return -ENOENT;

	if (event->attr.config != PERF_COUNT_SW_TASK_CLOCK)
		return -ENOENT;

	/*
	 * no branch sampling for software events
	 */
	if (has_branch_stack(event))
		return -EOPNOTSUPP;

	perf_swevent_init_hrtimer(event);

	return 0;
}

Project: linux
File: core.c

static void update_pmu_context(struct pmu *pmu, struct pmu *old_pmu)
{
	int cpu;

	for_each_possible_cpu(cpu) {
		struct perf_cpu_context *cpuctx;

		cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);

		if (cpuctx->unique_pmu == old_pmu)
			cpuctx->unique_pmu = pmu;
	}
}