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Subject: Re: [PATCH 7/8] arm64/perf: Add BRBE driver
To:     Anshuman Khandual <anshuman.khandual@arm.com>,
        linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org,
        peterz@infradead.org, acme@kernel.org, mark.rutland@arm.com,
        will@kernel.org
Cc:     Catalin Marinas <catalin.marinas@arm.com>,
        James Clark <james.clark@arm.com>,
        Rob Herring <robh@kernel.org>, Marc Zyngier <maz@kernel.org>,
        Ingo Molnar <mingo@redhat.com>,
        linux-perf-users@vger.kernel.org
References: <20220613100119.684673-1-anshuman.khandual@arm.com>
 <20220613100119.684673-8-anshuman.khandual@arm.com>
From:   German Gomez <german.gomez@arm.com>
Message-ID: <f84187d1-b7eb-e25e-090a-d09532f15594@arm.com>
Date:   Mon, 13 Jun 2022 13:16:19 +0100
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Hi Anshuman, thanks for the update,

As I mentioned offline, I have a perf test that I've been using for the
branch records and filters. I'll let you know the result using this set.

On 13/06/2022 11:01, Anshuman Khandual wrote:
> [...]
>
> +
> +static int brbe_fetch_perf_priv(u64 brbinf)
> +{
> +       int brbe_el = brbe_fetch_el(brbinf);
> +
> +       switch (brbe_el) {
> +       case BRBINF_EL_EL0:
> +               return PERF_BR_PRIV_USER;
> +       case BRBINF_EL_EL1:
> +               return PERF_BR_PRIV_KERNEL;
> +       case BRBINF_EL_EL2:
> +               if (is_kernel_in_hyp_mode())
> +                       return PERF_BR_PRIV_KERNEL;
> +               return PERF_BR_PRIV_HV;
> +       default:
> +               pr_warn("unknown branch privilege captured\n");
> +               return -1;

This looks like it should return PERF_BR_PRIV_UNKNOWN.

Thanks,
German

> +       }
> +}
> +
> +static void capture_brbe_flags(struct pmu_hw_events *cpuc, struct perf_event *event,
> +			       u64 brbinf, int idx)
> +{
>
> [...]
>
> +
> +	if (branch_sample_priv(event)) {
> +		/*
> +		 * All these information (i.e branch privilege level) are not
> +		 * available for source only branch records.
> +		 */
> +		if (type != BRBINF_VALID_SOURCE)
> +			cpuc->brbe_entries[idx].priv = brbe_fetch_perf_priv(brbinf);
> +	}
> +}
> +
>
> [...]