Re: [PATCH v10 09/12] arm64: disable SCS for hypervisor code

Kees Cook
2020-04-06T18:23:47Z

On Mon, Apr 06, 2020 at 09:41:18AM -0700, Sami Tolvanen wrote:
> Disable SCS for code that runs at a different exception level by
> adding __noscs to __hyp_text.
>
> Suggested-by: James Morse <james.morse@arm.com>
> Signed-off-by: Sami Tolvanen <samitolvanen@google.com>

Reviewed-by: Kees Cook <keescook@chromium.org>

-Kees

> Acked-by: Marc Zyngier <maz@kernel.org>
> ---
> arch/arm64/include/asm/kvm_hyp.h | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/arch/arm64/include/asm/kvm_hyp.h b/arch/arm64/include/asm/kvm_hyp.h
> index fe57f60f06a8..875b106c5d98 100644
> --- a/arch/arm64/include/asm/kvm_hyp.h
> +++ b/arch/arm64/include/asm/kvm_hyp.h
> @@ -13,7 +13,7 @@
> #include <asm/kvm_mmu.h>
> #include <asm/sysreg.h>
>
> -#define __hyp_text __section(.hyp.text) notrace
> +#define __hyp_text __section(.hyp.text) notrace __noscs
>
> #define read_sysreg_elx(r,nvh,vh) \
> ({ \
> --
> 2.26.0.292.g33ef6b2f38-goog
>

--
Kees Cook