Re: [PATCH 7/7] perf arm-spe: Don't hard code config attribute

Leo Yan
2025-12-02T12:28:43Z

On Mon, Dec 01, 2025 at 04:41:10PM +0000, Coresight ML wrote:
> Use the config attribute that's published by the driver instead of
> hard coding "attr.config".
>
> Signed-off-by: James Clark <james.clark@linaro.org>
> ---
> tools/perf/arch/arm64/util/arm-spe.c | 15 ++++++++-------
> 1 file changed, 8 insertions(+), 7 deletions(-)
>
> diff --git a/tools/perf/arch/arm64/util/arm-spe.c b/tools/perf/arch/arm64/util/arm-spe.c
> index d5ec1408d0ae..6c3dc97fde30 100644
> --- a/tools/perf/arch/arm64/util/arm-spe.c
> +++ b/tools/perf/arch/arm64/util/arm-spe.c
> @@ -256,7 +256,7 @@ static __u64 arm_spe_pmu__sample_period(const struct perf_pmu *arm_spe_pmu)
>
> static void arm_spe_setup_evsel(struct evsel *evsel, struct perf_cpu_map *cpus)
> {
> - u64 bit;
> + u64 pa_enable_bit;
>
> evsel->core.attr.freq = 0;
> evsel->core.attr.sample_period = arm_spe_pmu__sample_period(evsel->pmu);
> @@ -288,9 +288,10 @@ static void arm_spe_setup_evsel(struct evsel *evsel, struct perf_cpu_map *cpus)
> * inform that the resulting output's SPE samples contain physical addresses
> * where applicable.
> */
> - bit = perf_pmu__format_bits(evsel->pmu, "pa_enable");
> - if (evsel->core.attr.config & bit)
> - evsel__set_sample_bit(evsel, PHYS_ADDR);
> +
> + if (!evsel__get_config_val(evsel->pmu, evsel, "pa_enable", &pa_enable_bit))
> + if (pa_enable_bit)
> + evsel__set_sample_bit(evsel, PHYS_ADDR);

Hmm... I am a bit concerned for the evsel__get_config_val() usage
throughout the series.

evsel__get_config_val() returns a whole config value rather than the
bit field specified by the format name. If other bits (but not the
"pa_enable" bit) are set in the same config set, would it wrongly set
the PHYS_ADDR sample bit?

Seems to me, for reading specific format, perf_pmu__format_bits() is
more suitable than evsel__get_config_val().

Thanks,
Leo