diff mbox series

[v11,27/39] arm64: Add Kconfig for Guarded Control Stack (GCS)

Message ID 20240822-arm64-gcs-v11-27-41b81947ecb5@kernel.org (mailing list archive)
State Superseded
Headers show
Series arm64/gcs: Provide support for GCS in userspace | expand

Checks

Context Check Description
conchuod/vmtest-fixes-PR fail merge-conflict

Commit Message

Mark Brown Aug. 22, 2024, 1:15 a.m. UTC 
Provide a Kconfig option allowing the user to select if GCS support is
built into the kernel.

Reviewed-by: Thiago Jung Bauermann <thiago.bauermann@linaro.org>
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Mark Brown <broonie@kernel.org>
---
 arch/arm64/Kconfig | 20 ++++++++++++++++++++
 1 file changed, 20 insertions(+)

Comments

Catalin Marinas Aug. 23, 2024, 9:48 a.m. UTC | #1 
On Thu, Aug 22, 2024 at 02:15:30AM +0100, Mark Brown wrote:
> diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig
> index a2f8ff354ca6..772f9ba99fe8 100644
> --- a/arch/arm64/Kconfig
> +++ b/arch/arm64/Kconfig
> @@ -2137,6 +2137,26 @@ 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_HAS_USER_SHADOW_STACK
> +	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 # "v9.4 architectural features"

BTW, as Mark R spotted we'd also need to handle uprobes. Since that's
off in defconfig, I think it can be done separately on top of this
series. In the meantime, we could make this dependent on !UPROBES.
diff mbox series

Patch

diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig
index a2f8ff354ca6..772f9ba99fe8 100644
--- a/arch/arm64/Kconfig
+++ b/arch/arm64/Kconfig
@@ -2137,6 +2137,26 @@  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_HAS_USER_SHADOW_STACK
+	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 # "v9.4 architectural features"
+
 config ARM64_SVE
 	bool "ARM Scalable Vector Extension support"
 	default y