diff options
| -rw-r--r-- | tools/perf/util/cs-etm.c | 44 |
1 files changed, 44 insertions, 0 deletions
diff --git a/tools/perf/util/cs-etm.c b/tools/perf/util/cs-etm.c index a714b31656ea..8b3f882d6e2f 100644 --- a/tools/perf/util/cs-etm.c +++ b/tools/perf/util/cs-etm.c @@ -1372,6 +1372,20 @@ static int cs_etm__set_sample_flags(struct cs_etm_queue *etmq) if (prev_packet->sample_type == CS_ETM_DISCONTINUITY) prev_packet->flags |= PERF_IP_FLAG_BRANCH | PERF_IP_FLAG_TRACE_BEGIN; + + /* + * If the previous packet is an exception return packet + * and the return address just follows SVC instuction, + * it needs to calibrate the previous packet sample flags + * as PERF_IP_FLAG_SYSCALLRET. + */ + if (prev_packet->flags == (PERF_IP_FLAG_BRANCH | + PERF_IP_FLAG_RETURN | + PERF_IP_FLAG_INTERRUPT) && + cs_etm__is_svc_instr(etmq, packet, packet->start_addr)) + prev_packet->flags = PERF_IP_FLAG_BRANCH | + PERF_IP_FLAG_RETURN | + PERF_IP_FLAG_SYSCALLRET; break; case CS_ETM_DISCONTINUITY: /* @@ -1422,6 +1436,36 @@ static int cs_etm__set_sample_flags(struct cs_etm_queue *etmq) prev_packet->flags = packet->flags; break; case CS_ETM_EXCEPTION_RET: + /* + * When the exception return packet is inserted, since + * exception return packet is not used standalone for + * generating samples and it's affiliation to the previous + * instruction range packet; so set previous range packet + * flags to tell perf it is an exception return branch. + * + * The exception return can be for either system call or + * other exception types; unfortunately the packet doesn't + * contain exception type related info so we cannot decide + * the exception type purely based on exception return packet. + * If we record the exception number from exception packet and + * reuse it for excpetion return packet, this is not reliable + * due the trace can be discontinuity or the interrupt can + * be nested, thus the recorded exception number cannot be + * used for exception return packet for these two cases. + * + * For exception return packet, we only need to distinguish the + * packet is for system call or for other types. Thus the + * decision can be deferred when receive the next packet which + * contains the return address, based on the return address we + * can read out the previous instruction and check if it's a + * system call instruction and then calibrate the sample flag + * as needed. + */ + if (prev_packet->sample_type == CS_ETM_RANGE) + prev_packet->flags = PERF_IP_FLAG_BRANCH | + PERF_IP_FLAG_RETURN | + PERF_IP_FLAG_INTERRUPT; + break; case CS_ETM_EMPTY: default: break; |