arm64: add Permission Overlay Extension Kconfig

Now that support for POE and Protection Keys has been implemented, add a
config to allow users to actually enable it.

Signed-off-by: Joey Gouly <joey.gouly@arm.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will@kernel.org>
Reviewed-by: Anshuman Khandual <anshuman.khandual@arm.com>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Link: https://lore.kernel.org/r/20240822151113.1479789-24-joey.gouly@arm.com
Signed-off-by: Will Deacon <will@kernel.org>

diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig
index a2f8ff354ca670af50e44c790c6c201b63aa0ddb..35dfc627532861cb65e9d40f719d0facac3fdfd4 100644 (file)
--- a/arch/arm64/Kconfig
+++ b/arch/arm64/Kconfig
@@ -2137,6 +2137,29 @@ config ARM64_EPAN
          if the cpu does not implement the feature.
 endmenu # "ARMv8.7 architectural features"
 
+menu "ARMv8.9 architectural features"
+
+config ARM64_POE
+       prompt "Permission Overlay Extension"
+       def_bool y
+       select ARCH_USES_HIGH_VMA_FLAGS
+       select ARCH_HAS_PKEYS
+       help
+         The Permission Overlay Extension is used to implement Memory
+         Protection Keys. Memory Protection Keys provides a mechanism for
+         enforcing page-based protections, but without requiring modification
+         of the page tables when an application changes protection domains.
+
+         For details, see Documentation/core-api/protection-keys.rst
+
+         If unsure, say y.
+
+config ARCH_PKEY_BITS
+       int
+       default 3
+
+endmenu # "ARMv8.9 architectural features"
+
 config ARM64_SVE
        bool "ARM Scalable Vector Extension support"
        default y