[v10,26/40] arm64: Add Kconfig for Guarded Control Stack (GCS)

Commit Message

Mark Brown Aug. 1, 2024, 12:06 p.m. UTC

Provide a Kconfig option allowing the user to select if GCS support is
built into the kernel.

Reviewed-by: Thiago Jung Bauermann <[e-mail]>
Signed-off-by: Mark Brown <[e-mail]>
---
 arch/arm64/Kconfig | 20 ++++++++++++++++++++
 1 file changed, 20 insertions(+)

Comments

Catalin Marinas Aug. 21, 2024, 5:58 p.m. UTC | #1

On Thu, Aug 01, 2024 at 01:06:53PM +0100, Mark Brown wrote:
> Provide a Kconfig option allowing the user to select if GCS support is
> built into the kernel.
> 
> Reviewed-by: Thiago Jung Bauermann <[e-mail]>
> Signed-off-by: Mark Brown <[e-mail]>

Reviewed-by: Catalin Marinas <[e-mail]>

Patch

diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig
index b3fc891f1544..83e27857bc6a 100644
--- a/arch/arm64/Kconfig
+++ b/arch/arm64/Kconfig
@@ -2127,6 +2127,26 @@  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