Donate to e Foundation | Murena handsets with /e/OS | Own a part of Murena! Learn more

Commit f952eace authored by Adrian Hunter's avatar Adrian Hunter Committed by Arnaldo Carvalho de Melo
Browse files

perf intel-pt: Ensure never to set 'last_ip' when packet 'count' is zero 



Intel PT uses IP compression based on the last IP. For decoding purposes,
'last IP' is not updated when a branch target has been suppressed, which is
indicated by IPBytes == 0. IPBytes is stored in the packet 'count', so
ensure never to set 'last_ip' when packet 'count' is zero.

Signed-off-by: default avatarAdrian Hunter <adrian.hunter@intel.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: stable@vger.kernel.org
Link: http://lkml.kernel.org/r/1495786658-18063-7-git-send-email-adrian.hunter@intel.com


Signed-off-by: default avatarArnaldo Carvalho de Melo <acme@redhat.com>
parent ee14ac0e

tools/perf/util/intel-pt-decoder/intel-pt-decoder.c

+5 −3
Original line number Diff line number Diff line
@@ -1470,6 +1470,7 @@ static int intel_pt_walk_psbend(struct intel_pt_decoder *decoder) 


		case INTEL_PT_FUP:

			decoder->pge = true;

			if (decoder->packet.count)

				intel_pt_set_last_ip(decoder);

			break;
@@ -1756,8 +1757,9 @@ static int intel_pt_walk_trace(struct intel_pt_decoder *decoder) 


static inline bool intel_pt_have_ip(struct intel_pt_decoder *decoder)

{

	return decoder->have_last_ip || decoder->packet.count == 0 ||

	       decoder->packet.count == 3 || decoder->packet.count == 6;

	return decoder->packet.count &&

	       (decoder->have_last_ip || decoder->packet.count == 3 ||

		decoder->packet.count == 6);

}



/* Walk PSB+ packets to get in sync. */