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Message-ID: <422d2bce-b764-7894-12ac-d16ee3bdfbba@arm.com>
Date:   Thu, 8 Dec 2022 11:43:49 +0000
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Subject: Re: [PATCH V6 7/7] drivers: perf: arm_pmu: Enable branch stack
 sampling event
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To:     Anshuman Khandual <anshuman.khandual@arm.com>
Cc:     Catalin Marinas <catalin.marinas@arm.com>,
        Will Deacon <will@kernel.org>, Mark Brown <broonie@kernel.org>,
        Rob Herring <robh@kernel.org>, Marc Zyngier <maz@kernel.org>,
        Suzuki Poulose <suzuki.poulose@arm.com>,
        Peter Zijlstra <peterz@infradead.org>,
        Ingo Molnar <mingo@redhat.com>,
        Arnaldo Carvalho de Melo <acme@kernel.org>,
        linux-perf-users@vger.kernel.org,
        linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org,
        mark.rutland@arm.com
References: <20221208084402.863310-1-anshuman.khandual@arm.com>
 <20221208084402.863310-8-anshuman.khandual@arm.com>
From:   James Clark <james.clark@arm.com>
In-Reply-To: <20221208084402.863310-8-anshuman.khandual@arm.com>
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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@arm.com>

> Cc: Catalin Marinas <catalin.marinas@arm.com>
> Cc: Mark Rutland <mark.rutland@arm.com>
> Cc: Will Deacon <will@kernel.org>
> Cc: linux-kernel@vger.kernel.org
> Cc: linux-arm-kernel@lists.infradead.org
> Signed-off-by: Anshuman Khandual <anshuman.khandual@arm.com>
> ---
>  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)