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Date:   Thu, 16 Jan 2020 15:32:38 +0000
From:   Will Deacon <will@kernel.org>
To:     Sai Prakash Ranjan <saiprakash.ranjan@codeaurora.org>,
        jhugo@codeaurora.org
Cc:     Catalin Marinas <catalin.marinas@arm.com>,
        Marc Zyngier <maz@kernel.org>,
        Andre Przywara <andre.przywara@arm.com>,
        Mark Rutland <mark.rutland@arm.com>,
        linux-kernel@vger.kernel.org, linux-arm-msm@vger.kernel.org,
        linux-arm-kernel@lists.infradead.org,
        Douglas Anderson <dianders@chromium.org>,
        Stephen Boyd <swboyd@chromium.org>,
        Bjorn Andersson <bjorn.andersson@linaro.org>,
        Matthias Kaehlcke <mka@chromium.org>,
        James Morse <james.morse@arm.com>
Subject: Re: [PATCH] arm64: Add KRYO{3,4}XX CPU cores to spectre-v2 safe list
Message-ID: <20200116153235.GA18909@willie-the-truck>
References: <20200116141912.15465-1-saiprakash.ranjan@codeaurora.org>
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[+Jeffrey]

On Thu, Jan 16, 2020 at 07:49:12PM +0530, Sai Prakash Ranjan wrote:
> KRYO3XX silver CPU cores and KRYO4XX silver, gold CPU cores
> are not affected by Spectre variant 2. Add them to spectre_v2
> safe list to correct ARM_SMCCC_ARCH_WORKAROUND_1 warning and
> vulnerability sysfs value.
> 
> Signed-off-by: Sai Prakash Ranjan <saiprakash.ranjan@codeaurora.org>
> ---
>  arch/arm64/include/asm/cputype.h | 6 ++++++
>  arch/arm64/kernel/cpu_errata.c   | 3 +++
>  2 files changed, 9 insertions(+)
> 
> diff --git a/arch/arm64/include/asm/cputype.h b/arch/arm64/include/asm/cputype.h
> index aca07c2f6e6e..7219cddeba66 100644
> --- a/arch/arm64/include/asm/cputype.h
> +++ b/arch/arm64/include/asm/cputype.h
> @@ -85,6 +85,9 @@
>  #define QCOM_CPU_PART_FALKOR_V1		0x800
>  #define QCOM_CPU_PART_FALKOR		0xC00
>  #define QCOM_CPU_PART_KRYO		0x200
> +#define QCOM_CPU_PART_KRYO_3XX_SILVER	0x803
> +#define QCOM_CPU_PART_KRYO_4XX_GOLD	0x804
> +#define QCOM_CPU_PART_KRYO_4XX_SILVER	0x805

Jeffrey is the only person I know who understands the CPU naming here, so
I've added him in case this needs either renaming or extending to cover
other CPUs. I wouldn't be at all surprised if we need a function call
rather than a bunch of table entries...

That said, the internet claims that KRYO4XX gold is based on Cortex-A76,
and so CSV2 should be set...

Will