Re: [PATCH 26/35] arm64: Add Kconfig for Guarded Control Stack (GCS)

[Jonathan Cameron]

On Sun, 16 Jul 2023 22:51:22 +0100
Mark Brown <broonie@xxxxxxxxxx> wrote:

> Provide a Kconfig option allowing the user to select if GCS support is
> built into the kernel.
> 
> Signed-off-by: Mark Brown <broonie@xxxxxxxxxx>
> ---
>  arch/arm64/Kconfig | 19 +++++++++++++++++++
>  1 file changed, 19 insertions(+)
> 
> diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig
> index 7856c3a3e35a..e1aeeda13c52 100644
> --- a/arch/arm64/Kconfig
> +++ b/arch/arm64/Kconfig
> @@ -2091,6 +2091,25 @@ config ARM64_EPAN
>  	  if the cpu does not implement the feature.
>  endmenu # "ARMv8.7 architectural features"
>  
> +menu "v9.4 architectural features"
> +
> +config ARM64_GCS
> +	bool "Enable support for Guarded Control Stack (GCS)"
> +	default y
> +	select ARCH_USES_HIGH_VMA_FLAGS
> +	help
> +	  Guarded Control Stack (GCS) provides support for a separate
> +	  stack with restricted access which contains only return
> +	  addresses.  This can be used to harden against some attacks
> +	  by comparing return address used by the program with what is
> +	  stored in the GCS, and may also be used to efficiently obtain
> +	  the call stack for applications such as profiling.
> +
> +	  The feature is detected at runtime, and will remain disabled
> +	  if the system does not implement the feature.
> +
> +endmenu # "2022 archiectural features"

Inconsistent naming and spelling mistake.

> +
>  config ARM64_SVE
>  	bool "ARM Scalable Vector Extension support"
>  	default y
>