linux-kernel - [PATCH v1 4/4] perf cs-etm: Add support sample flags

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Date:   Sun, 28 Oct 2018 20:34:55 +0800
From:   Leo Yan <leo.yan@...aro.org>
To:     Arnaldo Carvalho de Melo <acme@...nel.org>,
        Mathieu Poirier <mathieu.poirier@...aro.org>,
        Alexander Shishkin <alexander.shishkin@...ux.intel.com>,
        Jiri Olsa <jolsa@...hat.com>,
        Namhyung Kim <namhyung@...nel.org>,
        linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org,
        Coresight ML <coresight@...ts.linaro.org>,
        Mike Leach <mike.leach@...aro.org>,
        Robert Walker <robert.walker@....com>,
        Al Grant <Al.Grant@....com>
Cc:     Leo Yan <leo.yan@...aro.org>
Subject: [PATCH v1 4/4] perf cs-etm: Add support sample flags

We have prepared the flags in the packet structure, so need to copy
the related value into sample structure thus perf tool can facilitate
sample flags.

The PREV_PACKET contains the branch instruction flags and PACKET
actually contains the flags for next branch instruction.  So this patch
is to set sample flags with 'etmq->prev_packet->flags'.

This patch includes two fixing up: if there has TRACE_ON packet in the
middle of instruction packets, the TRACE_ON packet indicates the trace
is discontinuous, so append the flag PERF_IP_FLAG_TRACE_END to the
previous packet; if the coming packet is exception packet or exception
return packet, also update the previous packet for exception specific
flags.

Signed-off-by: Leo Yan <leo.yan@...aro.org>
---
 tools/perf/util/cs-etm.c | 18 +++++++++++++++---
 1 file changed, 15 insertions(+), 3 deletions(-)

diff --git a/tools/perf/util/cs-etm.c b/tools/perf/util/cs-etm.c
index 00a95d7..7e36dcf 100644
--- a/tools/perf/util/cs-etm.c
+++ b/tools/perf/util/cs-etm.c
@@ -655,7 +655,7 @@ static int cs_etm__synth_instruction_sample(struct cs_etm_queue *etmq,
 	sample.stream_id = etmq->etm->instructions_id;
 	sample.period = period;
 	sample.cpu = etmq->packet->cpu;
-	sample.flags = 0;
+	sample.flags = etmq->prev_packet->flags;
 	sample.insn_len = 1;
 	sample.cpumode = event->header.misc;
 
@@ -711,7 +711,7 @@ static int cs_etm__synth_branch_sample(struct cs_etm_queue *etmq)
 	sample.stream_id = etmq->etm->branches_id;
 	sample.period = 1;
 	sample.cpu = etmq->packet->cpu;
-	sample.flags = 0;
+	sample.flags = etmq->prev_packet->flags;
 	sample.cpumode = PERF_RECORD_MISC_USER;
 
 	/*
@@ -945,9 +945,13 @@ static int cs_etm__exception(struct cs_etm_queue *etmq)
 	 * The exception packet includes the dummy address values, so don't
 	 * swap PACKET with PREV_PACKET.  This keeps PREV_PACKET to be useful
 	 * for generating instruction and branch samples.
+	 *
+	 * Also update flags so can tell perf it is exception related.
 	 */
-	if (etmq->prev_packet->sample_type == CS_ETM_RANGE)
+	if (etmq->prev_packet->sample_type == CS_ETM_RANGE) {
 		etmq->prev_packet->last_instr_taken_branch = true;
+		etmq->prev_packet->flags = etmq->packet->flags;
+	}
 
 	return 0;
 }
@@ -965,6 +969,14 @@ static int cs_etm__flush(struct cs_etm_queue *etmq)
 	if (etmq->prev_packet->sample_type == CS_ETM_EMPTY)
 		goto swap_packet;
 
+	/*
+	 * The start tracing packet is in the middle of instruction range
+	 * packets, this means the trace is discontinuous; so need to set
+	 * the previous packet flag to PERF_IP_FLAG_TRACE_END.
+	 */
+	if (etmq->prev_packet->sample_type == CS_ETM_RANGE)
+		etmq->prev_packet->flags |= PERF_IP_FLAG_TRACE_END;
+
 	if (etmq->etm->synth_opts.last_branch &&
 	    etmq->prev_packet->sample_type == CS_ETM_RANGE) {
 		/*
-- 
2.7.4