From: Adrian Hunter adrian.hunter@intel.com
commit c79ee2b2160909889df67c8801352d3e69d43a1a upstream.
An overflow (OVF packet) is treated as an error because it represents a loss of trace data, but there is no loss of synchronization, so the packet state should be INTEL_PT_STATE_IN_SYNC not INTEL_PT_STATE_ERR_RESYNC.
To support that, some additional variables must be reset, and the FUP packet that may follow OVF is treated as an FUP event.
Fixes: f4aa081949e7b6 ("perf tools: Add Intel PT decoder") Signed-off-by: Adrian Hunter adrian.hunter@intel.com Cc: Jiri Olsa jolsa@redhat.com Cc: stable@vger.kernel.org # v5.15+ Link: https://lore.kernel.org/r/20211210162303.2288710-5-adrian.hunter@intel.com Signed-off-by: Arnaldo Carvalho de Melo acme@redhat.com [Adrian: Backport to v5.10] Signed-off-by: Adrian Hunter adrian.hunter@intel.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- tools/perf/util/intel-pt-decoder/intel-pt-decoder.c | 32 +++++++++++++++++--- 1 file changed, 28 insertions(+), 4 deletions(-)
--- a/tools/perf/util/intel-pt-decoder/intel-pt-decoder.c +++ b/tools/perf/util/intel-pt-decoder/intel-pt-decoder.c @@ -1158,6 +1158,20 @@ static bool intel_pt_fup_event(struct in decoder->state.type |= INTEL_PT_BLK_ITEMS; ret = true; } + if (decoder->overflow) { + decoder->overflow = false; + if (!ret && !decoder->pge) { + if (decoder->hop) { + decoder->state.type = 0; + decoder->pkt_state = INTEL_PT_STATE_RESAMPLE; + } + decoder->pge = true; + decoder->state.type |= INTEL_PT_BRANCH | INTEL_PT_TRACE_BEGIN; + decoder->state.from_ip = 0; + decoder->state.to_ip = decoder->ip; + return true; + } + } if (ret) { decoder->state.from_ip = decoder->ip; decoder->state.to_ip = 0; @@ -1480,7 +1494,16 @@ static int intel_pt_overflow(struct inte intel_pt_log("ERROR: Buffer overflow\n"); intel_pt_clear_tx_flags(decoder); decoder->timestamp_insn_cnt = 0; - decoder->pkt_state = INTEL_PT_STATE_ERR_RESYNC; + decoder->pkt_state = INTEL_PT_STATE_IN_SYNC; + decoder->state.from_ip = decoder->ip; + decoder->ip = 0; + decoder->pge = false; + decoder->set_fup_tx_flags = false; + decoder->set_fup_ptw = false; + decoder->set_fup_mwait = false; + decoder->set_fup_pwre = false; + decoder->set_fup_exstop = false; + decoder->set_fup_bep = false; decoder->overflow = true; return -EOVERFLOW; } @@ -2083,6 +2106,7 @@ next:
case INTEL_PT_TIP_PGE: { decoder->pge = true; + decoder->overflow = false; intel_pt_mtc_cyc_cnt_pge(decoder); if (decoder->packet.count == 0) { intel_pt_log_at("Skipping zero TIP.PGE", @@ -2596,10 +2620,10 @@ static int intel_pt_sync_ip(struct intel decoder->set_fup_pwre = false; decoder->set_fup_exstop = false; decoder->set_fup_bep = false; + decoder->overflow = false;
if (!decoder->branch_enable) { decoder->pkt_state = INTEL_PT_STATE_IN_SYNC; - decoder->overflow = false; decoder->state.type = 0; /* Do not have a sample */ return 0; } @@ -2614,7 +2638,6 @@ static int intel_pt_sync_ip(struct intel decoder->pkt_state = INTEL_PT_STATE_RESAMPLE; else decoder->pkt_state = INTEL_PT_STATE_IN_SYNC; - decoder->overflow = false;
decoder->state.from_ip = 0; decoder->state.to_ip = decoder->ip; @@ -2823,7 +2846,8 @@ const struct intel_pt_state *intel_pt_de
if (err) { decoder->state.err = intel_pt_ext_err(err); - decoder->state.from_ip = decoder->ip; + if (err != -EOVERFLOW) + decoder->state.from_ip = decoder->ip; intel_pt_update_sample_time(decoder); decoder->sample_tot_cyc_cnt = decoder->tot_cyc_cnt; } else {