Re: [PATCH v4 22/29] 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>
---
 arch/arm64/Kconfig | 22 ++++++++++++++++++++++
 1 file changed, 22 insertions(+)

diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig
index 7b11c98b3e84..676ebe4bf9eb 100644
--- a/arch/arm64/Kconfig
+++ b/arch/arm64/Kconfig

@@ -2095,6 +2095,28 @@ 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