Re: [PATCH V6 7/7] drivers: perf: arm_pmu: Enable branch stack sampling event

[James Clark]

On 08/12/2022 08:44, Anshuman Khandual wrote:
> Now that all the required pieces are already in place, just enable the perf
> branch stack sampling event on supported platforms, removing the gate which
> blocks it unconditionally in armpmu_event_init(). Instead a quick probe can
> be initiated first via arm_pmu_branch_stack_supported().
> 

All the issues from the previous versions seem to be resolved now:

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

> Cc: Catalin Marinas <catalin.marinas@xxxxxxx>
> Cc: Mark Rutland <mark.rutland@xxxxxxx>
> Cc: Will Deacon <will@xxxxxxxxxx>
> Cc: linux-kernel@xxxxxxxxxxxxxxx
> Cc: linux-arm-kernel@xxxxxxxxxxxxxxxxxxx
> Signed-off-by: Anshuman Khandual <anshuman.khandual@xxxxxxx>
> ---
>  drivers/perf/arm_pmu.c | 3 +--
>  1 file changed, 1 insertion(+), 2 deletions(-)
> 
> diff --git a/drivers/perf/arm_pmu.c b/drivers/perf/arm_pmu.c
> index 66880a4bb248..52a93b9bcbda 100644
> --- a/drivers/perf/arm_pmu.c
> +++ b/drivers/perf/arm_pmu.c
> @@ -510,8 +510,7 @@ static int armpmu_event_init(struct perf_event *event)
>  		!cpumask_test_cpu(event->cpu, &armpmu->supported_cpus))
>  		return -ENOENT;
>  
> -	/* does not support taken branch sampling */
> -	if (has_branch_stack(event))
> +	if (has_branch_stack(event) && !arm_pmu_branch_stack_supported(armpmu))
>  		return -EOPNOTSUPP;
>  
>  	if (armpmu->map_event(event) == -ENOENT)