perf/x86/intel/pt: Add sampling support

	if (!nr_pages)

		return NULL;

	/*

	 * Only support AUX sampling in snapshot mode, where we don't

	 * generate NMIs.

	 */

	if (event->attr.aux_sample_size && !snapshot)

		return NULL;

	if (cpu == -1)

		cpu = raw_smp_processor_id();

	node = cpu_to_node(cpu);

	}

}

static long pt_event_snapshot_aux(struct perf_event *event,

				  struct perf_output_handle *handle,

				  unsigned long size)

{

	struct pt *pt = this_cpu_ptr(&pt_ctx);

	struct pt_buffer *buf = perf_get_aux(&pt->handle);

	unsigned long from = 0, to;

	long ret;

	if (WARN_ON_ONCE(!buf))

		return 0;

	/*

	 * Sampling is only allowed on snapshot events;

	 * see pt_buffer_setup_aux().

	 */

	if (WARN_ON_ONCE(!buf->snapshot))

		return 0;

	/*

	 * Here, handle_nmi tells us if the tracing is on

	 */

	if (READ_ONCE(pt->handle_nmi))

		pt_config_stop(event);

	pt_read_offset(buf);

	pt_update_head(pt);

	to = local_read(&buf->data_size);

	if (to < size)

		from = buf->nr_pages << PAGE_SHIFT;

	from += to - size;

	ret = perf_output_copy_aux(&pt->handle, handle, from, to);

	/*

	 * If the tracing was on when we turned up, restart it.

	 * Compiler barrier not needed as we couldn't have been

	 * preempted by anything that touches pt->handle_nmi.

	 */

	if (pt->handle_nmi)

		pt_config_start(event);

	return ret;

}

static void pt_event_del(struct perf_event *event, int mode)

{

	pt_event_stop(event, PERF_EF_UPDATE);

	pt_pmu.pmu.del			 = pt_event_del;

	pt_pmu.pmu.start		 = pt_event_start;

	pt_pmu.pmu.stop			 = pt_event_stop;

	pt_pmu.pmu.snapshot_aux		 = pt_event_snapshot_aux;

	pt_pmu.pmu.read			 = pt_event_read;

	pt_pmu.pmu.setup_aux		 = pt_buffer_setup_aux;

	pt_pmu.pmu.free_aux		 = pt_buffer_free_aux;