[PATCH 21/22] arm64: mte: Kconfig entry

[Catalin Marinas <catalin.marinas@arm.com>]

From: Vincenzo Frascino <vincenzo.frascino@arm.com>

Add Memory Tagging Extension support to the arm64 kbuild.

Signed-off-by: Vincenzo Frascino <vincenzo.frascino@arm.com>
Co-developed-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
---
 arch/arm64/Kconfig | 32 ++++++++++++++++++++++++++++++++
 1 file changed, 32 insertions(+)

diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig
index b1b4476ddb83..9a119c402bde 100644
--- a/arch/arm64/Kconfig
+++ b/arch/arm64/Kconfig
@@ -1484,6 +1484,38 @@ config ARM64_PTR_AUTH
 
 endmenu
 
+menu "ARMv8.5 architectural features"
+
+config ARM64_AS_HAS_MTE
+	def_bool $(as-instr,.arch armv8.5-a+memtag)
+
+config ARM64_MTE
+	bool "Memory Tagging Extension support"
+	depends on ARM64_AS_HAS_MTE && ARM64_TAGGED_ADDR_ABI
+	select ARCH_USES_HIGH_VMA_FLAGS
+	select ARCH_NO_SWAP
+	help
+	  Memory Tagging (part of the ARMv8.5 Extensions) provides
+	  architectural support for run-time, always-on detection of
+	  various classes of memory error to aid with software debugging
+	  to eliminate vulnerabilities arising from memory-unsafe
+	  languages.
+
+	  This option enables the support for the Memory Tagging
+	  Extension at EL0 (i.e. for userspace).
+
+	  Selecting this option allows the feature to be detected at
+	  runtime. Any secondary CPU not implementing this feature will
+	  not be allowed a late bring-up.
+
+	  Userspace binaries that want to use this feature must
+	  explicitly opt in. The mechanism for the userspace is
+	  described in:
+
+	  Documentation/arm64/memory-tagging-extension.rst.
+
+endmenu
+
 config ARM64_SVE
 	bool "ARM Scalable Vector Extension support"
 	default y