From: Vincenzo Frascino <vincenzo.frascino@xxxxxxx>
Add Memory Tagging Extension support to the arm64 kbuild.
Signed-off-by: Vincenzo Frascino <vincenzo.frascino@xxxxxxx>
Co-developed-by: Catalin Marinas <catalin.marinas@xxxxxxx>
Signed-off-by: Catalin Marinas <catalin.marinas@xxxxxxx>
Cc: Will Deacon <will@xxxxxxxxxx>
---
Notes:
v9:
- Slight improvement on the ARM64_AS_HAS_MTE comment.
v7:
- Binutils gained initial support for MTE in 2.32.0. However, a late
architecture addition (LDGM/STGM) is only supported in the newer
2.32.x and 2.33 versions. Change the AS_HAS_MTE option to also check
for stgm in addition to .arch armv8.5-a+memtag.
v6:
- Remove select ARCH_USES_PG_ARCH_2, no longer defined.
v5:
- Remove duplicate ARMv8.5 menu entry.
v4:
- select ARCH_USES_PG_ARCH_2.
- remove ARCH_NO_SWAP.
- default y.
arch/arm64/Kconfig | 33 +++++++++++++++++++++++++++++++++
1 file changed, 33 insertions(+)
diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig
index 6d232837cbee..e7450fbd0aa7 100644
--- a/arch/arm64/Kconfig
+++ b/arch/arm64/Kconfig
@@ -1664,6 +1664,39 @@ config ARCH_RANDOM
provides a high bandwidth, cryptographically secure
hardware random number generator.
+config ARM64_AS_HAS_MTE
+ # Initial support for MTE went in binutils 2.32.0, checked with
+ # ".arch armv8.5-a+memtag" below. However, this was incomplete
+ # as a late addition to the final architecture spec (LDGM/STGM)
+ # is only supported in the newer 2.32.x and 2.33 binutils
+ # versions, hence the extra "stgm" instruction check below.
+ def_bool $(as-instr,.arch armv8.5-a+memtag\nstgm xzr$(comma)[x0])
+
+config ARM64_MTE
+ bool "Memory Tagging Extension support"
+ default y
+ depends on ARM64_AS_HAS_MTE && ARM64_TAGGED_ADDR_ABI
+ select ARCH_USES_HIGH_VMA_FLAGS
+ 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
