linux-kernel - [PATCH 1/7] perf intel-pt: Fix some PGE usage

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Date:   Fri, 10 Dec 2021 18:22:57 +0200
From:   Adrian Hunter <adrian.hunter@...el.com>
To:     Arnaldo Carvalho de Melo <acme@...nel.org>
Cc:     Jiri Olsa <jolsa@...hat.com>, linux-kernel@...r.kernel.org
Subject: [PATCH 1/7] perf intel-pt: Fix some PGE usage

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: 839598176b0554 ("perf intel-pt: Allow decoding with branch tracing disabled")
Fixes: 7c1b16ba0e26e6 ("perf intel-pt: Add support for decoding FUP/TIP only")
Cc: stable@...r.kernel.org # v5.15+
Signed-off-by: Adrian Hunter <adrian.hunter@...el.com>
---
 tools/perf/util/intel-pt-decoder/intel-pt-decoder.c | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/tools/perf/util/intel-pt-decoder/intel-pt-decoder.c b/tools/perf/util/intel-pt-decoder/intel-pt-decoder.c
index 5f83937bf8f3..6f6f163161a9 100644
--- a/tools/perf/util/intel-pt-decoder/intel-pt-decoder.c
+++ b/tools/perf/util/intel-pt-decoder/intel-pt-decoder.c
@@ -2678,6 +2678,7 @@ static int intel_pt_hop_trace(struct intel_pt_decoder *decoder, bool *no_tip, in
 		return HOP_IGNORE;
 
 	case INTEL_PT_TIP_PGD:
+		decoder->pge = false;
 		if (!decoder->packet.count) {
 			intel_pt_set_nr(decoder);
 			return HOP_IGNORE;
@@ -2707,7 +2708,7 @@ static int intel_pt_hop_trace(struct intel_pt_decoder *decoder, bool *no_tip, in
 		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;
@@ -2897,7 +2898,7 @@ static bool intel_pt_psb_with_fup(struct intel_pt_decoder *decoder, int *err)
 {
 	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);
@@ -2999,7 +3000,7 @@ static int intel_pt_walk_trace(struct intel_pt_decoder *decoder)
 				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;
-- 
2.25.1