[PATCH 5.15 076/171] perf intel-pt: Fix some PGE (packet generation enable/control flow packets) usage

Greg Kroah-Hartman
2021-12-13T10:21:21Z

From: Adrian Hunter <adrian.hunter@intel.com>

commit 057ae59f5a1d924511beb1b09f395bdb316cfd03 upstream.

Packet generation enable (PGE) refers to whether control flow (COFI)
packets are being produced.

PGE may be false even when branch-tracing is enabled, due to being
out-of-context, or outside a filter address range. Fix some missing PGE
usage.

Fixes: 7c1b16ba0e26e6 ("perf intel-pt: Add support for decoding FUP/TIP only")
Fixes: 839598176b0554 ("perf intel-pt: Allow decoding with branch tracing disabled")
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/20211210162303.2288710-2-adrian.hunter@intel.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
tools/perf/util/intel-pt-decoder/intel-pt-decoder.c | 7 ++++---
1 file changed, 4 insertions(+), 3 deletions(-)

--- a/tools/perf/util/intel-pt-decoder/intel-pt-decoder.c
+++ b/tools/perf/util/intel-pt-decoder/intel-pt-decoder.c
@@ -2677,6 +2677,7 @@ static int intel_pt_hop_trace(struct int
return HOP_IGNORE;

case INTEL_PT_TIP_PGD:
+ decoder->pge = false;
if (!decoder->packet.count) {
intel_pt_set_nr(decoder);
return HOP_IGNORE;
@@ -2706,7 +2707,7 @@ static int intel_pt_hop_trace(struct int
intel_pt_set_ip(decoder);
if (intel_pt_fup_event(decoder))
return HOP_RETURN;
- if (!decoder->branch_enable)
+ if (!decoder->branch_enable || !decoder->pge)
*no_tip = true;
if (*no_tip) {
decoder->state.type = INTEL_PT_INSTRUCTION;
@@ -2896,7 +2897,7 @@ static bool intel_pt_psb_with_fup(struct
{
struct intel_pt_psb_info data = { .fup = false };

- if (!decoder->branch_enable || !decoder->pge)
+ if (!decoder->branch_enable)
return false;

intel_pt_pkt_lookahead(decoder, intel_pt_psb_lookahead_cb, &data);
@@ -2998,7 +2999,7 @@ next:
break;
}
intel_pt_set_last_ip(decoder);
- if (!decoder->branch_enable) {
+ if (!decoder->branch_enable || !decoder->pge) {
decoder->ip = decoder->last_ip;
if (intel_pt_fup_event(decoder))
return 0;