[PATCH 2/6] arm64: errata: Add QCOM_KRYO_2XX_GOLD to the spectre_bhb_firmware_mitigated_list

[Dmitry Baryshkov]

On Mon, Dec 09, 2024 at 09:43:12AM -0800, Douglas Anderson wrote:
> Qualcomm Kryo 200-series Gold cores appear to have a derivative of an
> ARM Cortex A73 in them. Since A73 needs Spectre mitigation then the
> Kyro 200-series Gold cores also should need Spectre mitigation.
> 
> Signed-off-by: Douglas Anderson <dianders at chromium.org>
> ---
> I don't really have any good way to test this patch but it seems
> likely it's needed. If nothing else the claim is that that Qualcomm
> Kyro 280 CPU is vulnerable [1] but I don't see any mitigations in the
> kernel for it.
> 
> NOTE: presumably this patch won't actually do much on its own because
> (I believe) it requires a firmware update to go with it.

Why? is_spectre_bhb_fw_affected() returns true if (cpu in list OR fw
mitigated)

> 
> [1] https://spectreattack.com/spectre.pdf
> 
>  arch/arm64/kernel/proton-pack.c | 1 +
>  1 file changed, 1 insertion(+)
> 
> diff --git a/arch/arm64/kernel/proton-pack.c b/arch/arm64/kernel/proton-pack.c
> index e149efadff20..0437be7c83bc 100644
> --- a/arch/arm64/kernel/proton-pack.c
> +++ b/arch/arm64/kernel/proton-pack.c
> @@ -925,6 +925,7 @@ static bool is_spectre_bhb_fw_affected(int scope)
>  	static const struct midr_range spectre_bhb_firmware_mitigated_list[] = {
>  		MIDR_ALL_VERSIONS(MIDR_CORTEX_A73),
>  		MIDR_ALL_VERSIONS(MIDR_CORTEX_A75),
> +		MIDR_ALL_VERSIONS(MIDR_QCOM_KRYO_2XX_GOLD),
>  		{},
>  	};
>  	bool cpu_in_list = is_midr_in_range_list(read_cpuid_id(),
> -- 
> 2.47.0.338.g60cca15819-goog
> 

-- 
With best wishes
Dmitry