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SubjectRe: [PATCH v2 7/8] drivers/perf: arm_pmu: Handle 47 bit counters
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On 01/12/2021 22.49, Marc Zyngier wrote:
> The current ARM PMU framework can only deal with 32 or 64bit counters.
> Teach it about a 47bit flavour.
>
> Yes, this is odd.
>
> Signed-off-by: Marc Zyngier <maz@kernel.org>
> ---
> drivers/perf/arm_pmu.c | 2 ++
> include/linux/perf/arm_pmu.h | 2 ++
> 2 files changed, 4 insertions(+)
>
> diff --git a/drivers/perf/arm_pmu.c b/drivers/perf/arm_pmu.c
> index 295cc7952d0e..0a9ed1a061ac 100644
> --- a/drivers/perf/arm_pmu.c
> +++ b/drivers/perf/arm_pmu.c
> @@ -109,6 +109,8 @@ static inline u64 arm_pmu_event_max_period(struct perf_event *event)
> {
> if (event->hw.flags & ARMPMU_EVT_64BIT)
> return GENMASK_ULL(63, 0);
> + else if (event->hw.flags & ARMPMU_EVT_47BIT)
> + return GENMASK_ULL(46, 0);
> else
> return GENMASK_ULL(31, 0);
> }
> diff --git a/include/linux/perf/arm_pmu.h b/include/linux/perf/arm_pmu.h
> index 2512e2f9cd4e..0407a38b470a 100644
> --- a/include/linux/perf/arm_pmu.h
> +++ b/include/linux/perf/arm_pmu.h
> @@ -26,6 +26,8 @@
> */
> /* Event uses a 64bit counter */
> #define ARMPMU_EVT_64BIT 1
> +/* Event uses a 47bit counter */
> +#define ARMPMU_EVT_47BIT 2
>
> #define HW_OP_UNSUPPORTED 0xFFFF
> #define C(_x) PERF_COUNT_HW_CACHE_##_x
>

Reviewed-by: Hector Martin <marcan@marcan.st>

--
Hector Martin (marcan@marcan.st)
Public Key: https://mrcn.st/pub

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