[PATCH 11/12] perf arm_spe: Set HITM flag

[James Clark]

On 13/06/2025 4:53 pm, Leo Yan wrote:
> Since FEAT_SPEv1p4, Arm SPE provides extra two 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 at linaro.org>

> Signed-off-by: Leo Yan <leo.yan at arm.com>
> ---
>   tools/perf/util/arm-spe-decoder/arm-spe-decoder.h |  2 ++
>   tools/perf/util/arm-spe.c                         | 26 +++++++++++++++++++++--
>   2 files changed, 26 insertions(+), 2 deletions(-)
> 
> 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 90c76928c7bf1b35cec538abdb0e88d6083fe81b..a2b48b0c87712f232587023eeaa66a9b83aed382 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_FETCH		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 8e93b0d151a98714d0c5e5f6ceec386a2aa63ad0..8a889f727f9cd5351b4ca027935112eddd16ea6c 100644
> --- a/tools/perf/util/arm-spe.c
> +++ b/tools/perf/util/arm-spe.c
> @@ -903,9 +903,12 @@ 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)
> @@ -916,6 +919,25 @@ 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_EVENTS] & 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;
>   }
> @@ -971,7 +993,7 @@ static u64 arm_spe__synth_data_source(struct arm_spe_queue *speq,
>   		return 0;
>   
>   	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;
>