Re: [PATCH V2 3/4] arm64/perf: Assert all platform event flags are within PERF_EVENT_FLAG_ARCH

[James Clark]

On 05/09/2022 06:42, Anshuman Khandual wrote:
> Ensure all platform specific event flags are within PERF_EVENT_FLAG_ARCH.
> 
> Cc: Will Deacon <will@xxxxxxxxxx>
> Cc: Catalin Marinas <catalin.marinas@xxxxxxx>
> Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
> Cc: Ingo Molnar <mingo@xxxxxxxxxx>
> Cc: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
> Cc: Mark Rutland <mark.rutland@xxxxxxx>
> Cc: Alexander Shishkin <alexander.shishkin@xxxxxxxxxxxxxxx>
> Cc: Jiri Olsa <jolsa@xxxxxxxxxx>
> Cc: Namhyung Kim <namhyung@xxxxxxxxxx>
> Cc: linux-arm-kernel@xxxxxxxxxxxxxxxxxxx
> Cc: linux-perf-users@xxxxxxxxxxxxxxx
> Cc: linux-kernel@xxxxxxxxxxxxxxx
> Signed-off-by: Anshuman Khandual <anshuman.khandual@xxxxxxx>
> ---
>  drivers/perf/arm_spe_pmu.c   | 4 +++-
>  include/linux/perf/arm_pmu.h | 9 +++++----
>  2 files changed, 8 insertions(+), 5 deletions(-)
> 
> diff --git a/drivers/perf/arm_spe_pmu.c b/drivers/perf/arm_spe_pmu.c
> index b65a7d9640e1..db8a0a841062 100644
> --- a/drivers/perf/arm_spe_pmu.c
> +++ b/drivers/perf/arm_spe_pmu.c
> @@ -44,7 +44,9 @@
>   * This allows us to perform the check, i.e, perfmon_capable(),
>   * in the context of the event owner, once, during the event_init().
>   */
> -#define SPE_PMU_HW_FLAGS_CX			BIT(0)
> +#define SPE_PMU_HW_FLAGS_CX			0x00001
> +
> +static_assert((PERF_EVENT_FLAG_ARCH & SPE_PMU_HW_FLAGS_CX) == SPE_PMU_HW_FLAGS_CX);
>  
>  static void set_spe_event_has_cx(struct perf_event *event)
>  {
> diff --git a/include/linux/perf/arm_pmu.h b/include/linux/perf/arm_pmu.h
> index 0407a38b470a..0356cb6a215d 100644
> --- a/include/linux/perf/arm_pmu.h
> +++ b/include/linux/perf/arm_pmu.h
> @@ -24,10 +24,11 @@
>  /*
>   * ARM PMU hw_event flags
>   */
> -/* Event uses a 64bit counter */
> -#define ARMPMU_EVT_64BIT		1
> -/* Event uses a 47bit counter */
> -#define ARMPMU_EVT_47BIT		2
> +#define ARMPMU_EVT_64BIT		0x00001 /* Event uses a 64bit counter */
> +#define ARMPMU_EVT_47BIT		0x00002 /* Event uses a 47bit counter */
> +

Minor nit:

I don't think changing the definitions to hex adds anything except more
noise in the git blame.

Either way, for the whole set:

Reviewed-by: James Clark <james.clark@xxxxxxx>

> +static_assert((PERF_EVENT_FLAG_ARCH & ARMPMU_EVT_64BIT) == ARMPMU_EVT_64BIT);
> +static_assert((PERF_EVENT_FLAG_ARCH & ARMPMU_EVT_47BIT) == ARMPMU_EVT_47BIT);
>  
>  #define HW_OP_UNSUPPORTED		0xFFFF
>  #define C(_x)				PERF_COUNT_HW_CACHE_##_x