Exemple #1
0
static void bts_event_start(struct perf_event *event, int flags)
{
	struct cpu_hw_events *cpuc = this_cpu_ptr(&cpu_hw_events);
	struct bts_ctx *bts = this_cpu_ptr(&bts_ctx);
	struct bts_buffer *buf;

	buf = perf_aux_output_begin(&bts->handle, event);
	if (!buf)
		goto fail_stop;

	if (bts_buffer_reset(buf, &bts->handle))
		goto fail_end_stop;

	bts->ds_back.bts_buffer_base = cpuc->ds->bts_buffer_base;
	bts->ds_back.bts_absolute_maximum = cpuc->ds->bts_absolute_maximum;
	bts->ds_back.bts_interrupt_threshold = cpuc->ds->bts_interrupt_threshold;

	event->hw.itrace_started = 1;
	event->hw.state = 0;

	__bts_event_start(event);

	return;

fail_end_stop:
	perf_aux_output_end(&bts->handle, 0, false);

fail_stop:
	event->hw.state = PERF_HES_STOPPED;
}
static int bts_event_add(struct perf_event *event, int mode)
{
	struct bts_buffer *buf;
	struct bts_ctx *bts = this_cpu_ptr(&bts_ctx);
	struct cpu_hw_events *cpuc = this_cpu_ptr(&cpu_hw_events);
	struct hw_perf_event *hwc = &event->hw;
	int ret = -EBUSY;

	event->hw.state = PERF_HES_STOPPED;

	if (test_bit(INTEL_PMC_IDX_FIXED_BTS, cpuc->active_mask))
		return -EBUSY;

	if (bts->handle.event)
		return -EBUSY;

	buf = perf_aux_output_begin(&bts->handle, event);
	if (!buf)
		return -EINVAL;

	ret = bts_buffer_reset(buf, &bts->handle);
	if (ret) {
		perf_aux_output_end(&bts->handle, 0, false);
		return ret;
	}

	bts->ds_back.bts_buffer_base = cpuc->ds->bts_buffer_base;
	bts->ds_back.bts_absolute_maximum = cpuc->ds->bts_absolute_maximum;
	bts->ds_back.bts_interrupt_threshold = cpuc->ds->bts_interrupt_threshold;

	if (mode & PERF_EF_START) {
		bts_event_start(event, 0);
		if (hwc->state & PERF_HES_STOPPED) {
			bts_event_del(event, 0);
			return -EBUSY;
		}
	}

	return 0;
}
int intel_bts_interrupt(void)
{
	struct bts_ctx *bts = this_cpu_ptr(&bts_ctx);
	struct perf_event *event = bts->handle.event;
	struct bts_buffer *buf;
	s64 old_head;
	int err;

	if (!event || !bts->started)
		return 0;

	buf = perf_get_aux(&bts->handle);
	/*
	 * Skip snapshot counters: they don't use the interrupt, but
	 * there's no other way of telling, because the pointer will
	 * keep moving
	 */
	if (!buf || buf->snapshot)
		return 0;

	old_head = local_read(&buf->head);
	bts_update(bts);

	/* no new data */
	if (old_head == local_read(&buf->head))
		return 0;

	perf_aux_output_end(&bts->handle, local_xchg(&buf->data_size, 0),
			    !!local_xchg(&buf->lost, 0));

	buf = perf_aux_output_begin(&bts->handle, event);
	if (!buf)
		return 1;

	err = bts_buffer_reset(buf, &bts->handle);
	if (err)
		perf_aux_output_end(&bts->handle, 0, false);

	return 1;
}
Exemple #4
0
int intel_bts_interrupt(void)
{
	struct debug_store *ds = this_cpu_ptr(&cpu_hw_events)->ds;
	struct bts_ctx *bts = this_cpu_ptr(&bts_ctx);
	struct perf_event *event = bts->handle.event;
	struct bts_buffer *buf;
	s64 old_head;
	int err = -ENOSPC, handled = 0;

	/*
	 * The only surefire way of knowing if this NMI is ours is by checking
	 * the write ptr against the PMI threshold.
	 */
	if (ds->bts_index >= ds->bts_interrupt_threshold)
		handled = 1;

	/*
	 * this is wrapped in intel_bts_enable_local/intel_bts_disable_local,
	 * so we can only be INACTIVE or STOPPED
	 */
	if (READ_ONCE(bts->state) == BTS_STATE_STOPPED)
		return handled;

	buf = perf_get_aux(&bts->handle);
	if (!buf)
		return handled;

	/*
	 * Skip snapshot counters: they don't use the interrupt, but
	 * there's no other way of telling, because the pointer will
	 * keep moving
	 */
	if (buf->snapshot)
		return 0;

	old_head = local_read(&buf->head);
	bts_update(bts);

	/* no new data */
	if (old_head == local_read(&buf->head))
		return handled;

	perf_aux_output_end(&bts->handle, local_xchg(&buf->data_size, 0),
			    !!local_xchg(&buf->lost, 0));

	buf = perf_aux_output_begin(&bts->handle, event);
	if (buf)
		err = bts_buffer_reset(buf, &bts->handle);

	if (err) {
		WRITE_ONCE(bts->state, BTS_STATE_STOPPED);

		if (buf) {
			/*
			 * BTS_STATE_STOPPED should be visible before
			 * cleared handle::event
			 */
			barrier();
			perf_aux_output_end(&bts->handle, 0, false);
		}
	}

	return 1;
}