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

Leo Yan
2026-04-02T08:55:29Z

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@linaro.org>

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

> ---
> 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
>
>