Re: [PATCH] arm64: Add KRYO{3,4}XX CPU cores to spectre-v2 safe list

[Will Deacon]

[+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@xxxxxxxxxxxxxx>
> ---
>  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