Re: [PATCH 1/4] perf arm_spe: Make a function to get the MIDR

[Leo Yan]

On Wed, Apr 01, 2026 at 03:25:49PM +0100, James Clark wrote:
> We'll need the MIDR to dump IMPDEF events in the next commits so extract
> a function for it.
> 
> No functional changes intended.
> 
> Signed-off-by: James Clark <james.clark@xxxxxxxxxx>

Reviewed-by: Leo Yan <leo.yan@xxxxxxx>

> ---
>  tools/perf/util/arm-spe.c | 36 ++++++++++++++++++++++--------------
>  1 file changed, 22 insertions(+), 14 deletions(-)
> 
> diff --git a/tools/perf/util/arm-spe.c b/tools/perf/util/arm-spe.c
> index 70dd9bee47c7..7447b000f9cd 100644
> --- a/tools/perf/util/arm-spe.c
> +++ b/tools/perf/util/arm-spe.c
> @@ -958,14 +958,9 @@ static void arm_spe__synth_memory_level(struct arm_spe_queue *speq,
>  	}
>  }
>  
> -static void arm_spe__synth_ds(struct arm_spe_queue *speq,
> -			      const struct arm_spe_record *record,
> -			      union perf_mem_data_src *data_src)
> +static int arm_spe__get_midr(struct arm_spe *spe, int cpu, u64 *midr)
>  {
> -	struct arm_spe *spe = speq->spe;
> -	u64 *metadata = NULL;
> -	u64 midr;
> -	unsigned int i;
> +	u64 *metadata;
>  
>  	/* Metadata version 1 assumes all CPUs are the same (old behavior) */
>  	if (spe->metadata_ver == 1) {
> @@ -973,15 +968,28 @@ static void arm_spe__synth_ds(struct arm_spe_queue *speq,
>  
>  		pr_warning_once("Old SPE metadata, re-record to improve decode accuracy\n");
>  		cpuid = perf_env__cpuid(perf_session__env(spe->session));
> -		midr = strtol(cpuid, NULL, 16);
> -	} else {
> -		metadata = arm_spe__get_metadata_by_cpu(spe, speq->cpu);
> -		if (!metadata)
> -			return;
> -
> -		midr = metadata[ARM_SPE_CPU_MIDR];
> +		*midr = strtol(cpuid, NULL, 16);
> +		return 0;
>  	}
>  
> +	metadata = arm_spe__get_metadata_by_cpu(spe, cpu);
> +	if (!metadata)
> +		return -EINVAL;
> +
> +	*midr = metadata[ARM_SPE_CPU_MIDR];
> +	return 0;
> +}
> +
> +static void arm_spe__synth_ds(struct arm_spe_queue *speq,
> +			      const struct arm_spe_record *record,
> +			      union perf_mem_data_src *data_src)
> +{
> +	u64 midr;
> +	unsigned int i;
> +
> +	if (arm_spe__get_midr(speq->spe, speq->cpu, &midr))
> +		return;
> +
>  	for (i = 0; i < ARRAY_SIZE(data_source_handles); i++) {
>  		if (is_midr_in_range_list(midr, data_source_handles[i].midr_ranges)) {
>  			return data_source_handles[i].ds_synth(record, data_src);
> 
> -- 
> 2.34.1
> 
>