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: Robert Walker <robert.wal...@arm.com>
---
tools/perf/util/cs-etm-decoder/cs-etm-decoder.c | 9 +++
tools/perf/util/cs-etm-decoder/cs-etm-decoder.h | 1 +
tools/perf/util/cs-etm.c | 84 +++++++++++++++++--------
3 files changed, 69 insertions(+), 25 deletions(-)
diff --git a/tools/perf/util/cs-etm-decoder/cs-etm-decoder.c
b/tools/perf/util/cs-etm-decoder/cs-etm-decoder.c
index 8ff69df..640af88 100644
--- a/tools/perf/util/cs-etm-decoder/cs-etm-decoder.c
+++ b/tools/perf/util/cs-etm-decoder/cs-etm-decoder.c
@@ -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:
diff --git a/tools/perf/util/cs-etm-decoder/cs-etm-decoder.h
b/tools/perf/util/cs-etm-decoder/cs-etm-decoder.h
index a4fdd28..743f5f4 100644
--- a/tools/perf/util/cs-etm-decoder/cs-etm-decoder.h
+++ b/tools/perf/util/cs-etm-decoder/cs-etm-decoder.h
@@ -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 {
diff --git a/tools/perf/util/cs-etm.c b/tools/perf/util/cs-etm.c
index 6777246..a8d07bd 100644
--- a/tools/perf/util/cs-etm.c
+++ b/tools/perf/util/cs-etm.c
@@ -866,6 +866,8 @@ static int cs_etm__sample(struct cs_etm_queue *etmq)
* PREV_PACKET is a branch.
*/
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);
@@ -918,6 +920,40 @@ 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;
@@ -946,20 +982,19 @@ static int cs_etm__run_decoder(struct cs_etm_queue *etmq)
/* Run trace decoder until buffer consumed or end of trace */
do {
processed = 0;
-
err = cs_etm_decoder__process_data_block(
etmq->decoder,
etmq->offset,
&buffer.buf[buffer_used],
buffer.len - buffer_used,
&processed);
-
if (err)
return err;
etmq->offset += processed;
buffer_used += processed;
+ /* Process each packet in this chunk */
while (1) {
err = cs_etm_decoder__get_packet(etmq->decoder,
etmq->packet);
@@ -970,32 +1005,31 @@ static int cs_etm__run_decoder(struct cs_etm_queue *etmq)
*/
break;
- /*
- * If the packet contains an instruction
- * range, generate instruction sequence
- * events.
- */
- if (etmq->packet->sample_type & CS_ETM_RANGE)
- err = cs_etm__sample(etmq);
+ switch (etmq->packet->sample_type) {
+ case CS_ETM_RANGE:
+ /*
+ * If the packet contains an instruction
+ * range, generate instruction sequence
+ * events.
+ */
+ cs_etm__sample(etmq);
+ break;
+ case CS_ETM_TRACE_ON:
+ /*
+ * Discontinuity in trace, flush
+ * previous branch stack
+ */
+ cs_etm__flush(etmq);
+ break;
+ default:
+ break;
+ }
}
} while (buffer.len > buffer_used);
- /*
- * Generate a last branch event for the branches left in
- * the circular buffer at the end of the trace.
- */
- 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;
- }
-
+ if (err == 0)
+ /* Flush any remaining branch stack entries */
+ err = cs_etm__flush(etmq);
}
return err;
--
2.7.4
