Re: [PATCH mm 2/2] Revert "kasan, arm64: don't allow SW_TAGS with ARM64_MTE"

[Marco Elver]

On Wed, 9 Dec 2020 at 19:24, Andrey Konovalov <andreyknvl@xxxxxxxxxx> wrote:
>
> This reverts "kasan, arm64: don't allow SW_TAGS with ARM64_MTE".
>
> In earlier versions on the hardware tag-based KASAN patchset in-kernel
> MTE used to be always enabled when CONFIG_ARM64_MTE is on. This caused
> conflicts with the software tag-based KASAN mode.
>
> This is no logner the case: in-kernel MTE is never enabled unless the
> CONFIG_KASAN_HW_TAGS is enabled, so there are no more conflicts with
> CONFIG_KASAN_SW_TAGS.
>
> Allow CONFIG_KASAN_SW_TAGS to be enabled even when CONFIG_ARM64_MTE is
> enabled.
>
> Signed-off-by: Andrey Konovalov <andreyknvl@xxxxxxxxxx>

Reviewed-by: Marco Elver <elver@xxxxxxxxxx>


> ---
>  arch/arm64/Kconfig | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig
> index 6fefab9041d8..62a7668976a2 100644
> --- a/arch/arm64/Kconfig
> +++ b/arch/arm64/Kconfig
> @@ -135,7 +135,7 @@ config ARM64
>         select HAVE_ARCH_JUMP_LABEL
>         select HAVE_ARCH_JUMP_LABEL_RELATIVE
>         select HAVE_ARCH_KASAN if !(ARM64_16K_PAGES && ARM64_VA_BITS_48)
> -       select HAVE_ARCH_KASAN_SW_TAGS if (HAVE_ARCH_KASAN && !ARM64_MTE)
> +       select HAVE_ARCH_KASAN_SW_TAGS if HAVE_ARCH_KASAN
>         select HAVE_ARCH_KASAN_HW_TAGS if (HAVE_ARCH_KASAN && ARM64_MTE)
>         select HAVE_ARCH_KFENCE
>         select HAVE_ARCH_KGDB
> --
> 2.29.2.576.ga3fc446d84-goog
>