From: Vincenzo Frascino Date: Fri, 6 Sep 2019 10:08:29 +0000 (+0100) Subject: arm64: mte: Kconfig entry X-Git-Url: http://git.maquefel.me/?a=commitdiff_plain;h=89b94df9dfb16fe29f9d2085b0a98116dc34d814;p=linux.git arm64: mte: Kconfig entry Add Memory Tagging Extension support to the arm64 kbuild. Signed-off-by: Vincenzo Frascino Co-developed-by: Catalin Marinas Signed-off-by: Catalin Marinas Cc: Will Deacon --- diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig index 6d232837cbeee..e7450fbd0aa7a 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