Commit 256e751c authored by Robert Walker's avatar Robert Walker Committed by Arnaldo Carvalho de Melo
Browse files

perf inject: Emit instruction records on ETM trace discontinuity 



There may be discontinuities in the ETM trace stream due to overflows or
ETM configuration for selective trace.  This patch emits an instruction
sample with the pending branch stack when a TRACE ON packet occurs
indicating a discontinuity in the trace data.

A new packet type CS_ETM_TRACE_ON is added, which is emitted by the low
level decoder when a TRACE ON occurs.  The higher level decoder flushes
the branch stack when this packet is emitted.

Signed-off-by: default avatarRobert Walker <robert.walker@arm.com>
Acked-by: default avatarMathieu Poirier <mathieu.poirier@linaro.org>
Cc: coresight@lists.linaro.org
Cc: linux-arm-kernel@lists.infradead.org
Link: http://lkml.kernel.org/r/1518607481-4059-3-git-send-email-robert.walker@arm.com


Signed-off-by: default avatarArnaldo Carvalho de Melo <acme@redhat.com>
parent e573e978

tools/perf/util/cs-etm-decoder/cs-etm-decoder.c

+9 −0
Original line number Diff line number Diff line
@@ -328,7 +328,14 @@ cs_etm_decoder__buffer_range(struct cs_etm_decoder *decoder, 
	}



	return ret;

}



static ocsd_datapath_resp_t

cs_etm_decoder__buffer_trace_on(struct cs_etm_decoder *decoder,

				const uint8_t trace_chan_id)

{

	return cs_etm_decoder__buffer_packet(decoder, trace_chan_id,

					     CS_ETM_TRACE_ON);

}



static ocsd_datapath_resp_t cs_etm_decoder__gen_trace_elem_printer(
@@ -347,6 +354,8 @@ static ocsd_datapath_resp_t cs_etm_decoder__gen_trace_elem_printer( 
		decoder->trace_on = false;

		break;

	case OCSD_GEN_TRC_ELEM_TRACE_ON:

		resp = cs_etm_decoder__buffer_trace_on(decoder,

						       trace_chan_id);

		decoder->trace_on = true;

		break;

	case OCSD_GEN_TRC_ELEM_INSTR_RANGE:

tools/perf/util/cs-etm-decoder/cs-etm-decoder.h

+1 −0
Original line number Diff line number Diff line
@@ -24,6 +24,7 @@ struct cs_etm_buffer { 


enum cs_etm_sample_type {

	CS_ETM_RANGE = 1 << 0,

	CS_ETM_TRACE_ON = 1 << 1,

};



struct cs_etm_packet {

tools/perf/util/cs-etm.c

+57 −23
Original line number Diff line number Diff line
@@ -867,6 +867,7 @@ static int cs_etm__sample(struct cs_etm_queue *etmq) 
	 */

	if (etm->synth_opts.last_branch &&

	    etmq->prev_packet &&

	    etmq->prev_packet->sample_type == CS_ETM_RANGE &&

	    etmq->prev_packet->last_instr_taken_branch)

		cs_etm__update_last_branch_rb(etmq);
@@ -920,6 +921,40 @@ static int cs_etm__sample(struct cs_etm_queue *etmq) 
	return 0;

}



static int cs_etm__flush(struct cs_etm_queue *etmq)

{

	int err = 0;

	struct cs_etm_packet *tmp;



	if (etmq->etm->synth_opts.last_branch &&

	    etmq->prev_packet &&

	    etmq->prev_packet->sample_type == CS_ETM_RANGE) {

		/*

		 * Generate a last branch event for the branches left in the

		 * circular buffer at the end of the trace.

		 *

		 * Use the address of the end of the last reported execution

		 * range

		 */

		u64 addr = cs_etm__last_executed_instr(etmq->prev_packet);



		err = cs_etm__synth_instruction_sample(

			etmq, addr,

			etmq->period_instructions);

		etmq->period_instructions = 0;



		/*

		 * Swap PACKET with PREV_PACKET: PACKET becomes PREV_PACKET for

		 * the next incoming packet.

		 */

		tmp = etmq->packet;

		etmq->packet = etmq->prev_packet;

		etmq->prev_packet = tmp;

	}



	return err;

}



static int cs_etm__run_decoder(struct cs_etm_queue *etmq)

{

	struct cs_etm_auxtrace *etm = etmq->etm;
@@ -971,32 +1006,31 @@ static int cs_etm__run_decoder(struct cs_etm_queue *etmq) 
					 */

					break;



				switch (etmq->packet->sample_type) {

				case CS_ETM_RANGE:

					/*

					 * If the packet contains an instruction

					 * range, generate instruction sequence

					 * events.

					 */

				if (etmq->packet->sample_type & CS_ETM_RANGE)

					err = cs_etm__sample(etmq);

			}

		} while (buffer.len > buffer_used);



					cs_etm__sample(etmq);

					break;

				case CS_ETM_TRACE_ON:

					/*

		 * Generate a last branch event for the branches left in

		 * the circular buffer at the end of the trace.

					 * Discontinuity in trace, flush

					 * previous branch stack

					 */

		if (etm->sample_instructions &&

		    etmq->etm->synth_opts.last_branch) {

			struct branch_stack *bs = etmq->last_branch_rb;

			struct branch_entry *be =

				&bs->entries[etmq->last_branch_pos];



			err = cs_etm__synth_instruction_sample(

				etmq, be->to, etmq->period_instructions);

			if (err)

				return err;

					cs_etm__flush(etmq);

					break;

				default:

					break;

				}

			}

		} while (buffer.len > buffer_used);



		if (err == 0)

			/* Flush any remaining branch stack entries */

			err = cs_etm__flush(etmq);

	}



	return err;

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