From: Leo Yan <leo.yan@arm.com>
Date: Fri, 12 Sep 2025 15:42:18 +0000 (+0100)
Subject: perf arm_spe: Set HITM flag
X-Git-Url: https://www.infradead.org/git/?a=commitdiff_plain;h=d510568970f38539eff41e6fe4ef76809f1b184c;p=users%2Fhch%2Fmisc.git

perf arm_spe: Set HITM flag

Since FEAT_SPEv1p4, Arm SPE provides two extra events: "Cache data
modified" and "Data snooped".

Set the snoop mode as:

- If both the "Cache data modified" event and the "Data snooped" event
  are set, which indicates a load operation that snooped from a outside
  cache and hit a modified copy, set the HITM flag to inspect false
  sharing.

- If the snooped event bit is not set, and the snooped event has been
  supported by the hardware, set as NONE mode (no snoop operation).

- If the snooped event bit is not set, and the event is not supported or
  absent the events info in the meta data, set as NA mode (not
  available).

Don't set any mode for only "Cache data modified" event, as it hits a
local modified copy.

Reviewed-by: James Clark <james.clark@linaro.org>
Signed-off-by: Leo Yan <leo.yan@arm.com>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Ali Saidi <alisaidi@amazon.com>
Cc: German Gomez <german.gomez@arm.com>
Cc: Ian Rogers <irogers@google.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Will Deacon <will@kernel.org>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
---

diff --git a/tools/perf/util/arm-spe-decoder/arm-spe-decoder.h b/tools/perf/util/arm-spe-decoder/arm-spe-decoder.h
index 3afa8703b21d..fbb57f805237 100644
--- a/tools/perf/util/arm-spe-decoder/arm-spe-decoder.h
+++ b/tools/perf/util/arm-spe-decoder/arm-spe-decoder.h
@@ -28,6 +28,8 @@
 #define ARM_SPE_L2D_ACCESS		BIT(EV_L2D_ACCESS)
 #define ARM_SPE_L2D_MISS		BIT(EV_L2D_MISS)
 #define ARM_SPE_RECENTLY_FETCHED	BIT(EV_RECENTLY_FETCHED)
+#define ARM_SPE_DATA_SNOOPED		BIT(EV_DATA_SNOOPED)
+#define ARM_SPE_HITM			BIT(EV_CACHE_DATA_MODIFIED)
 
 enum arm_spe_op_type {
 	/* First level operation type */
diff --git a/tools/perf/util/arm-spe.c b/tools/perf/util/arm-spe.c
index 58f80b5c0ab9..08cb493c3265 100644
--- a/tools/perf/util/arm-spe.c
+++ b/tools/perf/util/arm-spe.c
@@ -894,9 +894,12 @@ static void arm_spe__synth_st_memory_level(const struct arm_spe_record *record,
 	}
 }
 
-static void arm_spe__synth_memory_level(const struct arm_spe_record *record,
+static void arm_spe__synth_memory_level(struct arm_spe_queue *speq,
+					const struct arm_spe_record *record,
 					union perf_mem_data_src *data_src)
 {
+	struct arm_spe *spe = speq->spe;
+
 	if (data_src->mem_op == PERF_MEM_OP_LOAD)
 		arm_spe__synth_ld_memory_level(record, data_src);
 	if (data_src->mem_op == PERF_MEM_OP_STORE)
@@ -907,6 +910,25 @@ static void arm_spe__synth_memory_level(const struct arm_spe_record *record,
 		data_src->mem_lvl_num = PERF_MEM_LVLNUM_NA;
 	}
 
+	if (record->type & ARM_SPE_DATA_SNOOPED) {
+		if (record->type & ARM_SPE_HITM)
+			data_src->mem_snoop = PERF_MEM_SNOOP_HITM;
+		else
+			data_src->mem_snoop = PERF_MEM_SNOOP_HIT;
+	} else {
+		u64 *metadata = arm_spe__get_metadata_by_cpu(spe, speq->cpu);
+
+		/*
+		 * Set NA ("Not available") mode if no meta data or the
+		 * SNOOPED event is not supported.
+		 */
+		if (!metadata ||
+		    !(metadata[ARM_SPE_CAP_EVENT_FILTER] & ARM_SPE_DATA_SNOOPED))
+			data_src->mem_snoop = PERF_MEM_SNOOP_NA;
+		else
+			data_src->mem_snoop = PERF_MEM_SNOOP_NONE;
+	}
+
 	if (record->type & ARM_SPE_REMOTE_ACCESS)
 		data_src->mem_remote = PERF_MEM_REMOTE_REMOTE;
 }
@@ -963,7 +985,7 @@ arm_spe__synth_data_source(struct arm_spe_queue *speq,
 		return data_src;
 
 	if (!arm_spe__synth_ds(speq, record, &data_src))
-		arm_spe__synth_memory_level(record, &data_src);
+		arm_spe__synth_memory_level(speq, record, &data_src);
 
 	if (record->type & (ARM_SPE_TLB_ACCESS | ARM_SPE_TLB_MISS)) {
 		data_src.mem_dtlb = PERF_MEM_TLB_WK;