Re: [PATCH 1/2] perf inject: correct recording of branch address and destination

On Tue, May 23, 2017 at 09:09:30AM -0500, Sebastian Pop wrote:

ARM ETM traces contain packets of executed instructions. The addresses recorded in the trace correspond to the beginning and one instruction past the end of the block of executed instructions. In order to record the address and destination of executed branches, keep track of two packets: the jump occurs from the last executed instruction of the previous packet to the address of the first instruction in the current packet.

Signed-off-by: Sebastian Pop s.pop@samsung.com Signed-off-by: Brian Rzycki b.rzycki@samsung.com

---

tools/perf/util/cs-etm-decoder/cs-etm-decoder.c | 12 ++++ tools/perf/util/cs-etm-decoder/cs-etm-decoder.h | 1 + tools/perf/util/cs-etm.c | 91 +++++++++++++++++-------- 3 files changed, 75 insertions(+), 29 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 b4cbf4c..6164bfe 100644 --- a/tools/perf/util/cs-etm-decoder/cs-etm-decoder.c +++ b/tools/perf/util/cs-etm-decoder/cs-etm-decoder.c @@ -143,6 +143,18 @@ static int cs_etm_decoder__buffer_packet(struct cs_etm_decoder *decoder, decoder->packet_buffer[et].sample_type = sample_type; decoder->packet_buffer[et].start_addr = elem->st_addr; decoder->packet_buffer[et].end_addr = elem->en_addr;

• switch (elem->last_i_type) {
• case OCSD_INSTR_BR:
• case OCSD_INSTR_BR_INDIRECT:

• decoder->packet_buffer[et].last_instruction_is_branch = true;
  

• break;
  

• case OCSD_INSTR_OTHER:
• case OCSD_INSTR_ISB:
• case OCSD_INSTR_DSB_DMB:
• default:

• decoder->packet_buffer[et].last_instruction_is_branch = false;
  

• break;
  

• } decoder->packet_buffer[et].exc = false; decoder->packet_buffer[et].exc_ret = false; decoder->packet_buffer[et].cpu = *((int*)inode->priv);

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 d15a288..4fd5a9b 100644 --- a/tools/perf/util/cs-etm-decoder/cs-etm-decoder.h +++ b/tools/perf/util/cs-etm-decoder/cs-etm-decoder.h @@ -49,6 +49,7 @@ struct cs_etm_packet { enum cs_etm_sample_type sample_type; uint64_t start_addr; uint64_t end_addr;

• bool last_instruction_is_branch; bool exc; bool exc_ret; int cpu;

diff --git a/tools/perf/util/cs-etm.c b/tools/perf/util/cs-etm.c index 8270203..c99b728 100644 --- a/tools/perf/util/cs-etm.c +++ b/tools/perf/util/cs-etm.c @@ -104,6 +104,10 @@ struct cs_etm_queue { * inserted. */ size_t last_branch_pos;

• /*

• * A pointer to the last and current decoded packets.
  

• */
  

• struct cs_etm_packet *prev_packet, *packet;

}; static int cs_etm__get_trace(struct cs_etm_buffer *buff, struct cs_etm_queue *etmq); @@ -226,6 +230,8 @@ static void cs_etm__free_queue(void *priv) zfree(&etmq->event_buf); zfree(&etmq->last_branch); zfree(&etmq->last_branch_rb);

• zfree(&etmq->prev_packet);
• zfree(&etmq->packet); zfree(&etmq->chain); free(etmq);

} @@ -392,6 +398,7 @@ static struct cs_etm_queue *cs_etm__alloc_queue(struct cs_etm_auxtrace *etm, if (etm->synth_opts.last_branch) { size_t sz = sizeof(struct branch_stack);

• size_t szp = sizeof(struct cs_etm_packet);
  

sz += etm->synth_opts.last_branch_sz * sizeof(struct branch_entry); @@ -401,6 +408,12 @@ static struct cs_etm_queue *cs_etm__alloc_queue(struct cs_etm_auxtrace *etm, etmq->last_branch_rb = zalloc(sz); if (!etmq->last_branch_rb) goto out_free;

• etmq->prev_packet = zalloc(szp);
  

• if (!etmq->prev_packet)
  

• 	goto out_free;
  

• etmq->packet = zalloc(szp);
  

• if (!etmq->packet)
  

• 	goto out_free;
  

  }

etmq->event_buf = malloc(PERF_SAMPLE_MAX_SIZE); @@ -451,6 +464,8 @@ static struct cs_etm_queue *cs_etm__alloc_queue(struct cs_etm_auxtrace *etm, zfree(&etmq->event_buf); zfree(&etmq->last_branch); zfree(&etmq->last_branch_rb);

• zfree(&etmq->prev_packet);
• zfree(&etmq->packet); zfree(&etmq->chain); free(etmq); return NULL;

@@ -594,8 +609,7 @@ static inline void cs_etm__reset_last_branch_rb(struct cs_etm_queue *etmq) etmq->last_branch_rb->nr = 0; } -static void cs_etm__update_last_branch_rb(struct cs_etm_queue *etmq,

• 			  struct cs_etm_packet *packet)
  

+static void cs_etm__update_last_branch_rb(struct cs_etm_queue *etmq) { struct branch_stack *bs = etmq->last_branch_rb; struct branch_entry *be; @@ -611,10 +625,16 @@ static void cs_etm__update_last_branch_rb(struct cs_etm_queue *etmq, etmq->last_branch_pos -= 1;

• be = &bs->entries[etmq->last_branch_pos];
• be->from = packet->start_addr;
• be->to = packet->end_addr;
• /* No support for mispredict */

• be = &bs->entries[etmq->last_branch_pos];
• /*

• * The FROM address needs to be the instruction before the end of the
  

• * packet at END_ADDR: substract from END_ADDR the size of the last
  

• * instruction: 4 bytes.
  

• */
  

...and checkpatch complains about 'substract' being mispelled.

Thanks, Mathieu

• be->from = etmq->prev_packet->end_addr - 4;
• be->to = etmq->packet->start_addr;
• /* No support for mispredict. */ be->flags.mispred = 0; be->flags.predicted = 1;

@@ -721,13 +741,13 @@ static struct cs_etm_cache_entry *cs_etm__cache_lookup(struct dso *dso, } #endif -static int cs_etm__synth_instruction_sample(struct cs_etm_queue *etmq,

•                                       struct cs_etm_packet *packet)
  

+static int cs_etm__synth_instruction_sample(struct cs_etm_queue *etmq) { int ret = 0; struct cs_etm_auxtrace *etm = etmq->etm; union perf_event *event = etmq->event_buf; struct perf_sample sample = {.ip = 0,};

• struct cs_etm_packet *packet = etmq->packet; uint64_t start_addr = packet->start_addr; uint64_t end_addr = packet->end_addr;

@@ -941,17 +961,18 @@ static int cs_etm__synth_events(struct cs_etm_auxtrace *etm, static int cs_etm__sample(struct cs_etm_queue *etmq, int *cpu) {

•    //const struct cs_etm_state *state = etmq->state;
  

•    struct cs_etm_packet packet;
  

•    //struct cs_etm_auxtrace *etm = etmq->etm;
  

•    int err;
  

• struct cs_etm_auxtrace *etm = etmq->etm;
• struct cs_etm_packet *tmp;
• int err = cs_etm_decoder__get_packet(etmq->decoder, etmq->packet);

•    err = cs_etm_decoder__get_packet(etmq->decoder,&packet);
  

•    // if there is no sample, it returns err = -1, no real error
  

• /*

• * If there is no sample, it returns err = -1, no real error.
  

• */
  

  if (err) return err;

• if (etmq->etm->synth_opts.last_branch) {

• *cpu = packet.cpu;
  

• if (etm->synth_opts.last_branch) {

• *cpu = etmq->packet->cpu;
  

/* * FIXME: as the trace sampling does not work for now, (for @@ -961,17 +982,30 @@ static int cs_etm__sample(struct cs_etm_queue *etmq, int *cpu) * should be rewritten as "if reached sampling period". */ if (etmq->last_branch_rb->nr ==

•     etmq->etm->synth_opts.last_branch_sz) {
  

• 	err = cs_etm__synth_instruction_sample(etmq, &packet);
  

•     etm->synth_opts.last_branch_sz) {
  

• 	err = cs_etm__synth_instruction_sample(etmq);
  if (err)
  	return err;
  

  }

• cs_etm__update_last_branch_rb(etmq, &packet);
  

• } else if (packet.sample_type & CS_ETM_RANGE) {

•            err = cs_etm__synth_instruction_sample(etmq,&packet);
  

•            if (err)
  

•                    return err;
  

•    }
  

• /*
  

•  * Record a branch when the last instruction in PREV_PACKET is a
  

•  * branch.
  

•  */
  

• if (etmq->prev_packet->last_instruction_is_branch)
  

• 	cs_etm__update_last_branch_rb(etmq);
  

• /*
  

•  * 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;
  

• } else if (etmq->packet->sample_type & CS_ETM_RANGE) {

• err = cs_etm__synth_instruction_sample(etmq);
  

• if (err)
  

• 	return err;
  

• } return 0;

} @@ -1016,15 +1050,14 @@ static int cs_etm__run_decoder(struct cs_etm_queue *etmq, u64 *timestamp) * buffer at the end of the trace. */ if (etmq->etm->synth_opts.last_branch) {

• struct cs_etm_packet packet;
  

  struct branch_stack *bs = etmq->last_branch_rb; struct branch_entry *be = &bs->entries[etmq->last_branch_pos];

• packet.cpu = cpu;
  

• packet.start_addr = be->from;
  

• packet.end_addr = be->to;
  

• etmq->packet->cpu = cpu;
  

• etmq->packet->start_addr = be->to;
  

• etmq->packet->end_addr = be->to + 4;
  

• err = cs_etm__synth_instruction_sample(etmq, &packet);
  

• err = cs_etm__synth_instruction_sample(etmq);
  

  if (err) return err; }

-- 2.7.4