Re: [PATCH v4 30/39] arm64: kasan: Enable TBI EL1

[Catalin Marinas]

On Fri, Oct 02, 2020 at 01:10:31AM +0200, Andrey Konovalov wrote:
> From: Vincenzo Frascino <vincenzo.frascino@xxxxxxx>
> 
> Hardware tag-based KASAN relies on Memory Tagging Extension (MTE) that is
> built on top of the Top Byte Ignore (TBI) feature.
> 
> Enable in-kernel TBI when CONFIG_KASAN_HW_TAGS is turned on by enabling
> the TCR_TBI1 bit in proc.S.
> 
> Signed-off-by: Vincenzo Frascino <vincenzo.frascino@xxxxxxx>
> Co-developed-by: Andrey Konovalov <andreyknvl@xxxxxxxxxx>
> Signed-off-by: Andrey Konovalov <andreyknvl@xxxxxxxxxx>
> ---
> Change-Id: I91944903bc9c9c9044f0d50e74bcd6b9971d21ff
> ---
>  arch/arm64/mm/proc.S | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/arch/arm64/mm/proc.S b/arch/arm64/mm/proc.S
> index 6c1a6621d769..7c3304fb15d9 100644
> --- a/arch/arm64/mm/proc.S
> +++ b/arch/arm64/mm/proc.S
> @@ -46,7 +46,7 @@
>  #endif
>  
>  #ifdef CONFIG_KASAN_HW_TAGS
> -#define TCR_KASAN_HW_FLAGS SYS_TCR_EL1_TCMA1
> +#define TCR_KASAN_HW_FLAGS SYS_TCR_EL1_TCMA1 | TCR_TBI1
>  #else
>  #define TCR_KASAN_HW_FLAGS 0
>  #endif

Please merge this patch with the one one introducing TCR_KASAN_HW_FLAGS,
no need to have both around. You can add my Reviewed-by on that one.

-- 
Catalin