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.walker@arm.com Acked-by: Mathieu Poirier mathieu.poirier@linaro.org --- 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 | 80 ++++++++++++++++++------- 3 files changed, 67 insertions(+), 23 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 6e595d9..1b0d422 100644 --- a/tools/perf/util/cs-etm.c +++ b/tools/perf/util/cs-etm.c @@ -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;
- /* - * 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;