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

Leo Yan
2019-08-15T08:30:25Z

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@linaro.org>
Cc: Suzuki Poulouse <suzuki.poulose@arm.com>
Cc: Mike Leach <mike.leach@linaro.org>
Cc: Robert Walker <robert.walker@arm.com>
Cc: coresight@lists.linaro.org
Cc: linux-arm-kernel@lists.infradead.org
Signed-off-by: Leo Yan <leo.yan@linaro.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