linux-kernel - [PATCH 1/2] perf cs-etm: Support sample flags 'insn' and 'insnlen'

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Message-Id: <20190815082854.18191-1-leo.yan@linaro.org>
Date:   Thu, 15 Aug 2019 16:28:54 +0800
From:   Leo Yan <leo.yan@...aro.org>
To:     Arnaldo Carvalho de Melo <acme@...nel.org>,
        Alexander Shishkin <alexander.shishkin@...ux.intel.com>,
        Jiri Olsa <jolsa@...hat.com>,
        Namhyung Kim <namhyung@...nel.org>,
        Mathieu Poirier <mathieu.poirier@...aro.org>,
        Suzuki K Poulose <suzuki.poulose@....com>,
        linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org
Cc:     Leo Yan <leo.yan@...aro.org>, Mike Leach <mike.leach@...aro.org>,
        Robert Walker <robert.walker@....com>,
        coresight@...ts.linaro.org
Subject: [PATCH 1/2] perf cs-etm: Support sample flags 'insn' and 'insnlen'

The synthetic branch and instruction samples are missed to set
instruction related info, thus perf tool fails to display samples with
flags '-F,+insn,+insnlen'.

CoreSight trace decoder has provided sufficient information to decide
the instruction size based on the isa type: A64/A32 instruction are
32-bit size, but one exception is the T32 instruction size, which might
be 32-bit or 16-bit.

This patch handles for these cases and it reads the instruction values
from DSO file; thus can support flags '-F,+insn,+insnlen'.

Before:

  # perf script -F,insn,insnlen,ip,sym
                0 [unknown] ilen: 0
     ffff97174044 _start ilen: 0
     ffff97174938 _dl_start ilen: 0
     ffff97174938 _dl_start ilen: 0
     ffff97174938 _dl_start ilen: 0
     ffff97174938 _dl_start ilen: 0
     ffff97174938 _dl_start ilen: 0
     ffff97174938 _dl_start ilen: 0
     ffff97174938 _dl_start ilen: 0
     ffff97174938 _dl_start ilen: 0

  [...]

After:

  # perf script -F,insn,insnlen,ip,sym
                0 [unknown] ilen: 0
     ffff97174044 _start ilen: 4 insn: 2f 02 00 94
     ffff97174938 _dl_start ilen: 4 insn: c1 ff ff 54
     ffff97174938 _dl_start ilen: 4 insn: c1 ff ff 54
     ffff97174938 _dl_start ilen: 4 insn: c1 ff ff 54
     ffff97174938 _dl_start ilen: 4 insn: c1 ff ff 54
     ffff97174938 _dl_start ilen: 4 insn: c1 ff ff 54
     ffff97174938 _dl_start ilen: 4 insn: c1 ff ff 54
     ffff97174938 _dl_start ilen: 4 insn: c1 ff ff 54
     ffff97174938 _dl_start ilen: 4 insn: c1 ff ff 54

  [...]

Cc: Mathieu Poirier <mathieu.poirier@...aro.org>
Cc: Suzuki Poulouse <suzuki.poulose@....com>
Cc: Mike Leach <mike.leach@...aro.org>
Cc: Robert Walker <robert.walker@....com>
Cc: coresight@...ts.linaro.org
Cc: linux-arm-kernel@...ts.infradead.org
Signed-off-by: Leo Yan <leo.yan@...aro.org>
---
 tools/perf/util/cs-etm.c | 35 ++++++++++++++++++++++++++++++++++-
 1 file changed, 34 insertions(+), 1 deletion(-)

diff --git a/tools/perf/util/cs-etm.c b/tools/perf/util/cs-etm.c
index ed6f7fd5b90b..b3a5daaf1a8f 100644
--- a/tools/perf/util/cs-etm.c
+++ b/tools/perf/util/cs-etm.c
@@ -1076,6 +1076,35 @@ bool cs_etm__etmq_is_timeless(struct cs_etm_queue *etmq)
 	return !!etmq->etm->timeless_decoding;
 }
 
+static void cs_etm__copy_insn(struct cs_etm_queue *etmq,
+			      u64 trace_chan_id,
+			      const struct cs_etm_packet *packet,
+			      struct perf_sample *sample)
+{
+	/*
+	 * It's pointless to read instructions for the CS_ETM_DISCONTINUITY
+	 * packet, so directly bail out with 'insn_len' = 0.
+	 */
+	if (packet->sample_type == CS_ETM_DISCONTINUITY) {
+		sample->insn_len = 0;
+		return;
+	}
+
+	/*
+	 * T32 instruction size might be 32-bit or 16-bit, decide by calling
+	 * cs_etm__t32_instr_size().
+	 */
+	if (packet->isa == CS_ETM_ISA_T32)
+		sample->insn_len = cs_etm__t32_instr_size(etmq, trace_chan_id,
+							  sample->ip);
+	/* Otherwise, A64 and A32 instruction size are always 32-bit. */
+	else
+		sample->insn_len = 4;
+
+	cs_etm__mem_access(etmq, trace_chan_id, sample->ip,
+			   sample->insn_len, (void *)sample->insn);
+}
+
 static int cs_etm__synth_instruction_sample(struct cs_etm_queue *etmq,
 					    struct cs_etm_traceid_queue *tidq,
 					    u64 addr, u64 period)
@@ -1097,9 +1126,10 @@ static int cs_etm__synth_instruction_sample(struct cs_etm_queue *etmq,
 	sample.period = period;
 	sample.cpu = tidq->packet->cpu;
 	sample.flags = tidq->prev_packet->flags;
-	sample.insn_len = 1;
 	sample.cpumode = event->sample.header.misc;
 
+	cs_etm__copy_insn(etmq, tidq->trace_chan_id, tidq->packet, &sample);
+
 	if (etm->synth_opts.last_branch) {
 		cs_etm__copy_last_branch_rb(etmq, tidq);
 		sample.branch_stack = tidq->last_branch;
@@ -1159,6 +1189,9 @@ static int cs_etm__synth_branch_sample(struct cs_etm_queue *etmq,
 	sample.flags = tidq->prev_packet->flags;
 	sample.cpumode = event->sample.header.misc;
 
+	cs_etm__copy_insn(etmq, tidq->trace_chan_id, tidq->prev_packet,
+			  &sample);
+
 	/*
 	 * perf report cannot handle events without a branch stack
 	 */
-- 
2.17.1